Choked flow mechanism of HFC-134a flowing through short-tube orifices

Energy Technology Data Exchange (ETDEWEB)

Nilpueng, Kitti; Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab (FUTURE), Department of Mechanical Engineering, King Mongkut' s University of Technology Thonburi, Bangmod, Bangkok (Thailand)

2011-02-15

This paper is a continuation of the author's previous work. New experimental data on the occurrence of choked flow phenomenon and mass flow rate of HFC-134a inside short-tube orifices under choked flow condition are presented. Short-tube orifices diameters ranging from 0.406 mm to 0.686 mm with lengths ranging from 1 mm to 3 mm which can be applied to a miniature vapour-compression refrigeration system are examined. The experimental results indicated that the occurrence of choked flow phenomena inside short-tube orifices is different from that obtained from short-tube orifice diameters of greater than 1 mm, which are typically used in air-conditioner. The beginning of choked flow is dependent on the downstream pressure, degree of subcooling, and length-to-diameter ratio. Under choked flow condition, the mass flow rate is greatly varied with the short-tube orifice dimension, but it is slightly affected by the operating conditions. A correlation of mass flow rate through short-tube orifices is proposed in terms of the dimensionless parameters. The predicted results show good agreement with experimental data with a mean deviation of 4.69%. (author) transfer coefficient was also proposed. (author)

HFC-152a and HFC-134a emission estimates and characterization of CFCs, CFC replacements, and other halogenated solvents measured during the 2008 ARCTAS campaign (CARB phase over the South Coast Air Basin of California

Directory of Open Access Journals (Sweden)

B. Barletta

2011-03-01

Full Text Available This work presents results from the NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS study. Whole air samples were obtained on board research flights that flew over California during June 2008 and analyzed for selected volatile organic compounds, including several halogenated species. Samples collected over the South Coast Air Basin of California (SoCAB, which includes much of Los Angeles (LA County, were compared with samples from inflow air masses over the Pacific Ocean. The levels of many halocarbon species were enhanced significantly over the SoCAB, including compounds regulated by the Montreal Protocol and subsequent amendments. Emissions estimates of HFC-152a (1,1-difluoroethane, CH₃CHF₂; 0.82 ± 0.11 Gg and HFC-134a (1,1,1,2-tetrafluoroethane, CH₂FCF₃; 1.16 ± 0.22 Gg in LA County for 2008 were obtained using the observed HFC:carbon monoxide (CO enhancement ratio. Emission rates also were calculated for the SoCAB (1.60 ± 0.22 Gg yr⁻¹ for HFC-152a and 2.12 ± 0.28 Gg yr⁻¹ for HFC-134a and then extrapolated to the United States (32 ± 4 Gg yr⁻¹ for HFC-152a and 43 ± 6 Gg yr⁻¹ for HFC-134a using population data. In addition, emission rates of the two HFCs in LA County and SoCAB were calculated by a second method that utilizes air quality modeling. Emissions estimates obtained using both methods differ by less than 25% for the LA County and less than 45% for the SoCAB.

Investigation into the conditions under which HFC134a may become flammable.

CSIR Research Space (South Africa)

Kramers, AP

2002-01-01

Full Text Available or approaching 180°C would be associated with an onset of catastrophic conditions such as plant room fires and total mechanical failure of equipment. It is suggested in that the guidelines listed in Section 5.2, pertaining to abnormal plant conditions... /lubricant mixtures can become explosive. The work must therefore consider both normal and abnormal operating conditions to which HFC134a may be exposed to empower machine operators, mine maintenance personnel and contractors to take preventative...

Emissions of CO2, CO, NOx, HC, PM, HFC-134a, N2O and CH4 from the global light duty vehicle fleet

Directory of Open Access Journals (Sweden)

Timothy J. Wallington

2008-04-01

Full Text Available Vehicles emit carbon dioxide (CO2, carbon monoxide (CO, nitrogen oxides (NOx, hydrocarbons (HC, particulate matter (PM, hydrofluorocarbon 134a (HFC-134a, methane (CH4, and nitrous oxide (N2O. An understanding of these emissions is needed in discussions of climate change and local air pollution issues. To facilitate such discussions an overview of past, present, and likely future emissions from light duty vehicles is presented. Emission control technologies have reduced the emissions of CO, VOCs, PM, HFC-134a, CH4, and N2O from modern vehicles to very low levels.

Critical heat flux experimental facility using Freon R-134a fluid

Energy Technology Data Exchange (ETDEWEB)

Hong, Sung Deok; Chung, C. H.; Kim, B. D. [Korea Atomic Energy Research Institute, Taejeon (Korea)

2000-02-01

A CHF experimental loop using Freon R-134a as a working fluid has been designed and built to facilitate modeling of high pressure/temperature water CHF experiments. This loop was designed to operate at 4 MPa, 100 deg C with the maximum flow rate of 2.5 kg/s. The detailed technical specification and operating procedure of the loop are described together with comments on the performance and limitations of the loop. A series of CHF experiment was carried out in a vertical round tube and the fluid-to-fluid modeling techniques are applied for it's validity for the high temperature/pressure reactor conditions. The experimental range covered all the application ranges of CHF correlations developed for both PWR and PHWR. 28 refs., 9 figs., 5 tabs. (Author)

US emissions of HFC-134a derived for 2008-2012 from an extensive flask-air sampling network

NARCIS (Netherlands)

Hu, Lei; Montzka, Stephen A.; Miller, John B.; Andrews, Aryln E.; Lehman, Scott J.; Miller, Benjamin R.; Thoning, Kirk; Sweeney, Colm; Chen, Huilin; Godwin, David S.; Masarie, Kenneth; Bruhwiler, Lori; Fischer, Marc L.; Biraud, Sebastien C.; Torn, Margaret S.; Mountain, Marikate; Nehrkorn, Thomas; Eluszkiewicz, Janusz; Miller, Scot; Draxler, Roland R.; Stein, Ariel F.; Hall, Bradley D.; Elkins, James W.; Tans, Pieter P.

2015-01-01

U.S. national and regional emissions of HFC-134a are derived for 2008-2012 based on atmospheric observations from ground and aircraft sites across the U.S. and a newly developed regional inverse model. Synthetic data experiments were first conducted to optimize the model assimilation design and to

Inventory and mitigation opportunities for HFC-134a emissions from nonprofessional automotive service

Science.gov (United States)

Zhan, Tao; Potts, Winston; Collins, John F.; Austin, Jeff

2014-12-01

Many vehicle owners in the United States recharge their vehicles' air conditioning systems with small containers of hydrofluorocarbon-134a (HFC-134a, CH2FCF3), at a frequency estimated to be once every year on average. Such nonprofessional service produces immediate emissions of this potent greenhouse gas during service and from the residual heel in partially used containers. The nonprofessional operations are also associated with increased delayed refrigerant emissions that occur because owners are less likely to repair leaks than professional technicians. In California, an estimated 1.3 million nonprofessional service operations performed each year generate 0.27 ± 0.07 million metric ton CO2 equivalent (MMTCO2e) of immediate emissions and 0.54 ± 0.08 MMTCO2e of delayed emissions, using a Global Warming Potential of 1300 for HFC-134a. The immediate emissions can be largely mitigated by a regulation that requires self-sealing valves and improved labeling instructions on the containers, a deposit-return-recycling program for the containers, and a consumer education program. If 95% of the used containers were to be returned by consumers for recycling of the container heel, the annual immediate emissions would be reduced by 0.26 ± 0.07 MMTCO2e. In the United States, an estimated 24 million nonprofessional service operations are performed each year, generating 5.1 ± 1.4 MMTCO2e of immediate emissions and 10.4 ± 1.5 MMTCO2e of delayed emissions. Mitigation measures equivalent to the California regulation would reduce nationwide immediate emissions by 4.9 ± 1.4 MMTCO2e, if 95% of the used cans were returned for recycling. These business-as-usual emissions and mitigation potentials are projected to stay approximately constant until around 2022, and remain at significant levels into the 2030s.

Heat transfer during condensation of HFC-134a and R-404A inside of a horizontal smooth and micro-fin tube

Energy Technology Data Exchange (ETDEWEB)

Sapali, S N [Govt. College of Engineering, Department of Mechanical Engineering, Shivaji Nagar, Pune, Maharashtra 411 005 (India); Patil, Pradeep A [AISSMS College of Engineering, Pune University, Mechanical Engineering Department, Kennedy Road, Near R.T.O., Pune, Maharashtra 411 001 (India)

2010-11-15

In recent small and medium capacity refrigeration systems, the condenser tubes are provided with micro-fins from inside. The vapour refrigerant at the compressor outlet and the condenser inlet is in superheat state. As it advances in the condenser it is in two phases and at the outlet it is in sub cooled liquid. The heat transfer coefficient (HTC) during condensation of HFC-134a and R-404A in a smooth (8.56 mm ID) and micro-fin tubes (8.96 mm ID) are experimentally investigated. Different from previous studies, the present experiments are performed for various condensing temperatures, with superheating and sub cooling and using hermetically sealed compressor. The test runs are done at average saturated condensing temperatures ranging from 35 C to 60 C. The mass fluxes are between 90 and 800 kg m{sup -2} s{sup -1}. The experimental results indicate that the average HTC increases with mass flux but decreases with increasing condensing temperature for both smooth and micro-fin tubes. The average condensation HTCs of HFC-134a and R-404A for the micro-fin tubes were 1.5-2.5 and 1.3-2 times larger than that in smooth tube respectively. The HTCs for R-404A are less than that of HFC-134a. New correlations based on the data gathered during the experimentation for predicting condensation HTCs are proposed for wide range of operating conditions. (author)

An experimental investigation on the substitution of HFC134a with HFO1234YF in a domestic refrigerator

International Nuclear Information System (INIS)

Aprea, Ciro; Greco, Adriana; Maiorino, Angelo

2016-01-01

Highlights: • An experimental comparison between R134A and HFO1234YF is presented. • A domestic refrigerator made to work with R134A is analysed. • The annual energy consumptions of the device are reported. • The energy saving achievable after the drop-in is evaluated. - Abstract: The latest international regulations on the reduction of greenhouse gases are strongly redesigning the scenario of use of refrigerants, gradually eliminating the possibility of employing the HFCs. Among all sectors of refrigeration, one of the most affected by these restrictions is the domestic refrigeration. Although for it have been suggested some solutions, such as the construction of household refrigerator operating with the hydrocarbons, there remains the need to find a substitute for HFC134a. In particular, the substitution may involve both existing machines and already in operation, which cannot be loaded with hydrocarbons, and new devices. With the aim of finding a simple implementation solution, in the present work, it is reported an experimental investigation carried out on a domestic refrigerator designed and built to operate with HFC134a and for which a drop-in with HFO1234yf has been realised. The experimentation has been addressed so as to highlight the behaviour of the system as a result of the drop-in, with a particular interest in the energy performance variation. A slight energy saving has been recorded with HFO1234yf, and an improving of the cooling capacity has been noticed.

Viscosity measurements and correlations of binary mixtures: 1,1,1,2-tetrafluoroethane (HFC-134a)+tetraethylene glycol dimethylether (TEGDME)

DEFF Research Database (Denmark)

Monsalvo, Matias Alfonso; Baylaucq, A.; Reghem, P.

2005-01-01

.15-373.15 K. The measurements have been carried out with a failing body viscometer for four molar fractions x(1) =(0.28, 0.44, 0.63 and 0.88). The density values of this system were interpolated from previous results obtained at the laboratory. All of the available viscosity data, including pure HFC-134a...

HFO1234ze(E) And HFC134a Flow Boiling Inside a 4mm Horizontal Smooth Tube

OpenAIRE

Longo, Giovanni A.; Mancin, Simone; Righetti, Giulia; Zilio, Claudio

2016-01-01

Nowadays, the substitution of HFC134a with low GWP refrigerants is one of the most important challenge for refrigeration and air conditioning. The possible substitutes include natural refrigerants, such as HC600 (Butane) and HC600a (Isobutane), and also synthetic refrigerants, such as HFO1234yf and HFO1234ze(E). The HC refrigerants exhibit very low GWP, 3 and 4 HC600a and HC600 respectively, good thermodynamic and transport properties, and pressure and volumetric performance very similar to H...

Water plasma generation under atmospheric pressure for HFC destruction

International Nuclear Information System (INIS)

Watanabe, Takayuki; Tsuru, Taira

2008-01-01

The purpose of this paper is to investigate the decomposition process of hydrofluoroethylene (HFC-134a) by water plasmas. The water plasma was generated by DC arc discharge with a cathode of hafnium embedded into a copper rod and a nozzle-type copper anode. The advantage of the water plasma torch is the generation of 100%-water plasma by DC discharge. The distinctive steam generation leads to the portable light-weight plasma generation system that does not require the gas supply unit, as well as the high energy efficiency owing to the nonnecessity of the additional water-cooling. HFC-134a was injected into the water plasma jet to decompose it in the reaction tube. Neutralization vessel was combined to the reaction tube to absorb F 2 and HF generated from the HFC-134a decomposition. The decomposition was performed with changing the feed rate of HFC-134a up to 185 mmol/min. The decomposition efficiency of 99.9% can be obtained up to 0.43 mmol/kJ of the ratio of HFC-134a feed rate to the arc power, hence the maximum feed rate was estimated to be 160 g/h at 1 kW of the arc power

Performance Analysis of a Centrifugal Compressor for HFC-134a with aviation of Diffuser Vane Angle

International Nuclear Information System (INIS)

Park, Han Young; Chung, Jin Taek; Shin, You Hwan; Lee, Yoon Pyo; Kim, Kwang Ho; Cho, Yong Hun; Kim, Jong Seong

2007-01-01

Numerical simulation on the two-stage centrifugal compressor with Low Solidity Vaned Diffuser (LSVD) for HFC-134a turbo-chiller was performed using a commercial code. The comparative study with experimental results from other compressor was also investigated to testify the simulation schemes. The numerical analysis was separately simulated for each stage of the compressor and the effect of impeller-diffuser flow interaction was considered. Setting angle of the diffuser vane changed in the range of 15 .deg. and the effects on its variation were discussed in detail including the flow analysis in the passage of the compressor. The vane setting angle obtained from the preliminary design was slightly adjusted to the optimal value by the performance enhancement in terms of pressure recovery and flow characteristics

Performance and energy saving analysis of a refrigerator using hydrocarbon mixture (HC-R134a) as working fluid

Science.gov (United States)

Mohtar, M. N.; Nasution, H.; Aziz, A. A.

2015-12-01

The use of hydrocarbon mixture as a working fluid in a refrigerator system is rarely explored. Almost all domestic refrigerators use hydroflourocarbon R134a (HFC-R134a) as refrigerants. In this study, hydrocarbon gas (HC-R134a) is used as the alternative refrigerant to replace HFC-R134a. It has a composition of R290 (56%), R600a (54.39%) and additive (0.1%wt) blended for the trials. The experiments were conducted with 105 g and 52.5 g refrigerant mass charge, subjected to internal heat load of 0, 1, 2, 3 and 4 kg respectively. The study investigates the coefficient of performance of the refrigerator (COPR) and energy consumption. The results show that the use of HC-R134a as the replaceable refrigerant can save energy ranging from 2.04% to 7.09%, as compared to the conventional HFC-R134a refrigerant. Naturally, the COPR improvement and temperature distribution using HC-R134a are much better than HFC-R134a

Power Optimization of Organic Rankine-cycle System with Low-Temperature Heat Source Using HFC-134a

Energy Technology Data Exchange (ETDEWEB)

Baik, Young Jin; Kim, Min Sung; Chang, Ki Chang; Lee, Young Soo; Ra, Ho Sang [Korea Institute of Energy Research, Daejeon (Korea, Republic of)

2011-01-15

In this study, an organic Rankine-cycle system using HFC-134a, which is a power cycle corresponding to a low temperature heat source, such as that for geothermal power generation, was investigated from the view point of power optimization. In contrast to conventional approaches, the heat transfer and pressure drop characteristics of the working fluid within the heat exchangers were taken into account by using a discretized heat exchanger model. The inlet flow rates and temperatures of both the heat source and the heat sink were fixed. The total heat transfer area was fixed, whereas the heat-exchanger areas of the evaporator and the condenser were allocated to maximize the power output. The power was optimized on the basis of three design parameters. The optimal combination of parameters that can maximize power output was determined on the basis of the results of the study. The results also indicate that the evaporation process has to be optimized to increase the power output.

CFC and HFC recycling equipments: Test performances

International Nuclear Information System (INIS)

Picini, P.; Caropreso, G.; Cicoli, G.; Posarelli, M.

1996-12-01

Actual regulatory conditions about ozone layer depleting chemicals set problems on their disposal and on the management of plants still using illegal CFCs. Anyway fluids that will replace CFCs (i.e. HFCs) will not be allowed to be spread into the atmosphere, due to their high costs and to the greenhouse effect. A viable solution would be the recovery, purification and recycle of contaminated fluids. ENEA (National Agency for New Technology, Energy and the Environment), in cooperation with ICF (Industria Componenti Frigoriferi) Company leader in the field of air refrigerating and conditioning, patented a device able to extract, to clean and to recycle CFC 12 and HFC 134a in the refrigerating systems. This paper presents experimental data from the qualification tests on a device performing the above mentioned operations regarding systems that use HFC 134a as process fluid

Operation of Resistive Plate Chamber Detectors with a New Environmentally Friendly Freon

CERN Document Server

Lewis, Helen Elizabeth

2014-01-01

RPC particle gas detectors at CERN provide a vital element to the physics experiments carried out on the LHC. While their current operation and working gas mixtures are successful, environ- mental and economic factors force a revision of the mixture, specifically the eventual replacement of the current Freon gas R134-a with a newer, less environmentally harmful formulation, namely R1234-yf. The methods and results presented here outline the detector response to the introduction of the new Freon and its behavior under various mixtures. The electronegativity and hence impact on RPC parameters was investigated. It was found that the new Freon gas is indeed electroneg- ative, and suppresses the RPC signal. The mixture was modified to include Argon to increase ionization, and the final results of the operation of the RPC were satisfactory. Further work to refine the mixture for future implementation is necessary.

Evaporation of refrigerant HFC 407C on plain tubes or at an improved surface; Evaporation du refrigerant HFC 407C sur des tubes lisses ou a surface amelioree

Energy Technology Data Exchange (ETDEWEB)

Zuercher, O.; Favrat, D.; Thome, J. R.; Kattan, N.; Nidegger, E. [Ecole polytechnique federale, Lab. d` energetique industrielle, Lausanne (Switzerland)

1996-11-15

The substitution of CFC refrigerants in refrigeration systems, heat pumps and organic Rankine cycles for heat recovery, requires good methods for predicting heat transfer of substitute fluids. The measurements in the LENI test facility (concentric tubes with water flowing in a counter-current flow) with HFC 407C, HFC 134a, HCFC 123, HFC 404a and HFC/HCFC 402A provide a new data bank for new refrigerants, and allow a coherent comparison with old refrigerants CFC 11, CFC 12, CFC/HCFC 502 and with existing correlations. The existing correlations were found to be inadequate. Because of this work, an improved flow pattern map and flow boiling model were developed, which resulted in a substantial progress in the accurate predict of heat transfer in plain, horizontal tubes for refrigerants without oil. The Kattan et al. correlation was programmed to calculate and compare predicted heat transfer coefficients to the new HFC 407C test data. The flow pattern map proposed by Kattan et al. was also programmed and compared to flow regimes observed for HFC 407C. It predicted the HFC 407C flow pattern data quite accurately. The original objective of the HFC 407C measurements was the validation of the Kattan et al. correlation applied to a zeotropic refrigerant blend. Local flow boiling heat transfer coefficients were measured for HFC 407C evaporating inside a microfin and a plain tube. In addition, microfin heat transfer augmentation relative to a plain tube was investigated. The presence of oil in the evaporator had a complex effect on heat transfer coefficients. Local flow boiling heat transfer coefficients were measured for refrigerant HFC 407C ester oil mixtures (Mobil EAL Arctic 68). A new thermodynamic approach for modeling mixtures of zeotropic refrigerant blends and lubricating oils was also developed. (author) figs., tabs., 14 refs.

Global emissions of the hydrofluorocarbons (HFCs) HFC-365mfc, HFC-245fa, HFC-227ea, and HFC-236fa based on atmospheric observations

Science.gov (United States)

Vollmer, M. K.; Miller, B. R.; Rigby, M. L.; Reimann, S.; Muhle, J.; Agage, Soge, Snu Members, Kopri Members

2010-12-01

We report on the atmospheric measurements and global emissions of the hydrofluorocarbons (HFCs) HFC-365mfc (CH3CH2CF2CF3, 1,1,1,3,3-pentafluorobutane), HFC-245fa (CHF2CH2CF3, 1,1,1,3,3-pentafluoropropane), HFC-227ea (CF3CHFCF3, 1,1,1,2,3,3,3-heptafluoropropane), and HFC-236fa (CF3CH2CF3, 1,1,1,3,3,3-hexafluoropropane). These measurements are from in-situ observations at stations of AGAGE (Advanced Global Atmospheric Gases Experiment) and SOGE (System for Observations of Halogenated Greenhouse Gases in Europe), and from the Korean station Gosan. We also report on flask sample measurements from the Antarctic stations King Sejong and Troll, and extend our records back to the 1970s using archived air samples of both hemispheres. All data are used in a global 12-box 2-dimensional atmospheric transport model to derive global abundances and emission estimates. All four HFCs have strongly increased in the atmosphere in recent years with growth rates at nearly 10 %, resulting in dry air mole fractions at the end of 2009 of 0.49 ppt for HFC-365mfc, 1.00 ppt for HFC-245fa, and 0.51 ppt for HFC-227ea. HFC-236fa, for which we report the first atmospheric measurements, is less abundant and has grown to 0.069 ppt at the end of 2009. Our model results show rapidly growing emissions of HFC-365mfc and HFC-245fa after 2002 but surprisingly these have now started to decline to globally 2.7 kt/yr (HFC-365mfc) and 6.1 kt/yr (HFC-245fa). On the other hand HFC-227ea and HFC-236fa show uninterrupted growth in their emissions of 2.5 kt/yr and 0.2 kt/yr at the end of 2009.

Atmospheric histories and global emissions of the anthropogenic hydrofluorocarbons HFC-365mfc, HFC-245fa, HFC-227ea, and HFC-236fa

Science.gov (United States)

Vollmer, Martin K.; Miller, Benjamin R.; Rigby, Matthew; Reimann, Stefan; Mühle, Jens; Krummel, Paul B.; O'Doherty, Simon; Kim, Jooil; Rhee, Tae Siek; Weiss, Ray F.; Fraser, Paul J.; Simmonds, Peter G.; Salameh, Peter K.; Harth, Christina M.; Wang, Ray H. J.; Steele, L. Paul; Young, Dickon; Lunder, Chris R.; Hermansen, Ove; Ivy, Diane; Arnold, Tim; Schmidbauer, Norbert; Kim, Kyung-Ryul; Greally, Brian R.; Hill, Matthias; Leist, Michael; Wenger, Angelina; Prinn, Ronald G.

2011-04-01

We report on ground-based atmospheric measurements and emission estimates of the four anthropogenic hydrofluorocarbons (HFCs) HFC-365mfc (CH3CF2CH2CF3, 1,1,1,3,3-pentafluorobutane), HFC-245fa (CHF2CH2CF3, 1,1,1,3,3-pentafluoropropane), HFC-227ea (CF3CHFCF3, 1,1,1,2,3,3,3-heptafluoropropane), and HFC-236fa (CF3CH2CF3, 1,1,1,3,3,3-hexafluoropropane). In situ measurements are from the global monitoring sites of the Advanced Global Atmospheric Gases Experiment (AGAGE), the System for Observations of Halogenated Greenhouse Gases in Europe (SOGE), and Gosan (South Korea). We include the first halocarbon flask sample measurements from the Antarctic research stations King Sejong and Troll. We also present measurements of archived air samples from both hemispheres back to the 1970s. We use a two-dimensional atmospheric transport model to simulate global atmospheric abundances and to estimate global emissions. HFC-365mfc and HFC-245fa first appeared in the atmosphere only ˜1 decade ago; they have grown rapidly to globally averaged dry air mole fractions of 0.53 ppt (in parts per trillion, 10-12) and 1.1 ppt, respectively, by the end of 2010. In contrast, HFC-227ea first appeared in the global atmosphere in the 1980s and has since grown to ˜0.58 ppt. We report the first measurements of HFC-236fa in the atmosphere. This long-lived compound was present in the atmosphere at only 0.074 ppt in 2010. All four substances exhibit yearly growth rates of >8% yr-1 at the end of 2010. We find rapidly increasing emissions for the foam-blowing compounds HFC-365mfc and HFC-245fa starting in ˜2002. After peaking in 2006 (HFC-365mfc: 3.2 kt yr-1, HFC-245fa: 6.5 kt yr-1), emissions began to decline. Our results for these two compounds suggest that recent estimates from long-term projections (to the late 21st century) have strongly overestimated emissions for the early years of the projections (˜2005-2010). Global HFC-227ea and HFC-236fa emissions have grown to average values of 2.4 kt yr-1

Two-phase flow characteristics of HFC and HCFC fluid

International Nuclear Information System (INIS)

Ueno, T.; Matsuda, K.; Kusakabe, T.

1998-01-01

Some two-phase flow characteristics of HFC and HCFC fluid have been investigated experimentally. Fluids used in this experiment are HCFC22 (hereinafter called 'R22'), HCFC123 (hereinafter called 'R123') and Mixture of HFC fluid (hereinafter called 'R407C'). The fluid R407C are mixture of HFC32, HFC134a and HFC125, and their concentrations are 23wt%, 52wt% and 25wt%, respectively. This paper presents main flow parameters such as void fraction, interfacial velocities, bubble diameter distribution and pressure drop multiplier, which can characterize flow behavior. The void fractions and interfacial velocities were measured at some local positions in the single pipe using the bi-optical probe(hereinafter called 'BOP'). The procedure to calculate the void fraction from the void signals obtained by BOP were adopted the so-called slice method. The effects of slice levels on the void fraction were discussed taking into account bubble diameter. The new correlation of slice level as the function of void fraction has been proposed. The area-averaged void fractions obtained from BOP's void signals using new correlation were compared with void fractions obtained from pressure drops. The area-averaged interfacial velocities were also compared with the superficial gas velocities. It was concluded that the accuracy of BOP measurements are 5% for void fraction and less than 8.5% for interfacial velocity

Identification of volatiles by headspace gas chromatography with simultaneous flame ionization and mass spectrometric detection.

Science.gov (United States)

Tiscione, Nicholas B; Yeatman, Dustin Tate; Shan, Xiaoqin; Kahl, Joseph H

2013-10-01

Volatiles are frequently abused as inhalants. The methods used for identification are generally nonspecific if analyzed concurrently with ethanol or require an additional analytical procedure that employs mass spectrometry. A previously published technique utilizing a capillary flow technology splitter to simultaneously quantitate and confirm ethyl alcohol by flame ionization and mass spectrometric detection after headspace sampling and gas chromatographic separation was evaluated for the detection of inhalants. Methanol, isopropanol, acetone, acetaldehyde, toluene, methyl ethyl ketone, isoamyl alcohol, isobutyl alcohol, n-butyl alcohol, 1,1-difluoroethane, 1,1,1-trifluoroethane, 1,1,1,2-tetrafluoroethane (Norflurane, HFC-134a), chloroethane, trichlorofluoromethane (Freon®-11), dichlorodifluoromethane (Freon®-12), dichlorofluoromethane (Freon®-21), chlorodifluoromethane (Freon®-22) and 1,2-dichlorotetrafluoroethane (Freon®-114) were validated for qualitative identification by this method. The validation for qualitative identification included evaluation of matrix effects, sensitivity, carryover, specificity, repeatability and ruggedness/robustness.

Modelling of fluid flow through short tube orifices under metastable conditions: A new numerical validation approach for evaluating the mass flow rate with refrigerant mixtures (HFC-407C and HFC-410A)

International Nuclear Information System (INIS)

García-Valladares, O.; Santoyo, E.

2014-01-01

In a previous work, one-dimensional numerical modelling of fluid-flow inside short tube orifices was performed, and successfully validated against a wide range of mass flow rate measurements reported for the refrigerant HFC-134a. Governing equations of continuity, momentum, energy and entropy were solved for describing the fluid flow under a wide variety of thermodynamic transitions (e.g., subcooled liquid region, metastable liquid region, metastable two-phase region and equilibrium two-phase region), including sudden contraction and enlargement. In this new study, a comprehensive comparison analysis between numerical simulation data and experimental measurements obtained for HFC-407C and HFC-410A refrigerants (N o  = 241) to extend the applicability of the same mathematical model was carried out. Using a widespread statistical analysis, based on weighted linear regressions with an outlier detection/rejection module at 95% of confidence level, the prediction performance of the mathematical model was again assessed. Linear regressions between predicted mass flow rate data and experimental measurements were computed, and used them as a statistical comparison criterion. A statistical comparison between predicted simulation results and mass flow rate experimental data are reported. Average deviation errors of ±11.1% (for the refrigerant HFC-407C) and ±7.3% (for refrigerant HFC-410A) were found between numerical model and experimental data. These results demonstrate a new and robust application of the model to predict reliably the mass flow rate through short tube orifices under metastable conditions, which enable this tool to be reliably used for the design of short tube orifices. - Highlights: •A modelling for evaluating short tube orifice was developed for refrigerant mixtures. •The numerical model applied considered metastable regions and choke flow. •The model was validated against experimental data for HFC-407C and HFC-410A. •Statistical analysis based

Sudden death involving inhalation of 1,1-difluoroethane (HFC-152a) with spray cleaner: three case reports.

Science.gov (United States)

Sakai, Kentaro; Maruyama-Maebashi, Kyoko; Takatsu, Akihiro; Fukui, Kenji; Nagai, Tomonori; Aoyagi, Miwako; Ochiai, Eriko; Iwadate, Kimiharu

2011-03-20

Spray cleaner is a cleaning product containing compressed 1,1-difluoroethane (HFC-152a) to blow dust off electric devices and other sensitive equipment; however, it is also inhaled to induce euphoria. This report describes three cases of death involving HFC-152a inhalation with spray cleaner under different circumstances. In case 1, death was during inhalation for euphoria with which led to having frostbite. In case 2, death may have been associated with suicidal intention. Case 3 was also considered an accidental autoerotic death. In all three cases, HFC-152a was detected at 99.2-136.2mg/l in blood samples, 94.5-191.9 mg/l in urine samples and 3.6-18.4 mg in the gastric contents according to gas chromatography with flame ionization detection. To prevent death associated with HFC-152a inhalation from spray cleaner, the danger of the sudden death should be announced to people, given the ready availability of commercial products containing HFC-152a. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Vapor Explosions with Subcooled Freon

International Nuclear Information System (INIS)

Henry, R.E.; Fauske, Hans K.; McUmber, L.M.

1976-01-01

Explosive vapor formation accompanied by destructive shock waves, can be produced when two liquids, at much different temperatures, are brought into intimate contact. A proposed analytical model states that the interface temperature upon contact between the two liquid systems, gust be greater than or equal to the spontaneous nucleation temperature of that liquid-liquid system and that the thermal boundary layer must be sufficiently developed to support a critical size cavity. For time scales greater than 10-12 sec, the interface temperature upon contact of two semi-infinite masses, with constant thermal properties, can be related to the initial liquid temperatures. The spontaneous nucleation behavior at the interface can either be heterogeneous or homogeneous in nature. In either case, the critical size cavities, which initiate the vaporization process, are produced by local density fluctuations within the cold liquid. For homogeneous conditions, the two liquids present a well-wetted system and the vapor embryos are produced entirely within the cold liquid. For heterogeneous conditions, which result from poor, or imperfect wetting, at the liquid-liquid interface, the critical sized cavities are created at the interface at somewhat lower temperatures. A sequence of experiments, using Freon-22 and water, Freon-22 and mineral oil, and Freon-12 and mineral oil have been performed to test this spontaneous nucleation premise. For Freon-22 at its normal boiling point, the interface temperature of the water must be at least 77 deg. C before the interface temperature equals or exceeds the minimum homogeneous nucleation value of 54 deg. C and 84 deg. C before the interface temperature equals 60 deg. C where the homogeneous nucleation rate becomes truly explosive. The Freon-water test demonstrated explosive interactions for water temperatures considerably lower than this value and this was attributed to the heterogeneous nucleation characteristics of that particular system

High-aspect-ratio HfC nanobelts accompanied by HfC nanowires: Synthesis, characterization and field emission properties

Energy Technology Data Exchange (ETDEWEB)

Tian, Song, E-mail: tiansong22@126.com [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China); School of Materials Science and Engineering, Chongqing Jiaotong University, Chongqing 400074 (China); Zhang, Yulei; Ren, Jincui; Qiang, Xinfa; Zhang, Shouyang [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China); Li, Hejun, E-mail: lihejun@nwpu.edu.cn [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China)

2017-04-30

Highlights: • HfC naobelts accompanied by HfC nanowires were synthesized by a catalytic CVD method. • HfC nanobelts as a novel structure of HfC ceramic are reported for the first time. • HfC nanobelts have 100–200 μm in lengths and reach up to 10 μm in widths. • The synthesized product is promising field nanoemitters. - Abstract: As a key refractory carbide, hafnium carbide (HfC) is commonly used as structural materials while the field emission (FE) application of HfC in the field of vacuum microelectronics is almost the only one for functional material purposes. Based on its outstanding physical and chemical characteristics, HfC is identified as a potential candidate with satisfactory mechanical properties and long-term and/or high-temperature FE stability for future applications in high-performance field emitters. However, the development of HfC in various FE applications is hindered because it is not facile to fabricate large-scale low-dimensional HfC field nanoemitters. Herein, High-aspect-ratio HfC nanobelts accompanied by HfC nanowires were synthesized on a large scale by a traditional and simple catalytic chemical vapor deposition (CVD) method. Classical vapor–liquid–solid (VLS) theory was employed to explain the growth of the HfC nanowires and nanobelts along axial direction. The thin HfO{sub 2} shell and thin C layer surrounding the nanostructures might give rise to the diameter fluctuation of HfC nanowires and the width increase of HfC nanobelts in lateral direction. Field emission results show that the high-aspect-ratio HfC nanobelts accompanied by the nanowires are promising field nanoemitters, which exhibit excellent field emission properties with a fairly low turn-on field of ∼1.5 V μm{sup −1} and a low current fluctuation less than ∼10%. This suggests that HfC ceramics with high-aspect-ratio nanostructures are ideal cathode material for various field emission applications.

ANALISIS PERBANDINGAN EVAPORATOR KULKAS (LEMARI ES DENGAN MENGUNAKAN REFRIGERANT R-22 DAN R-134A

Directory of Open Access Journals (Sweden)

Imam Faozan

2017-03-01

Full Text Available Tulisan ini bertujuan untuk mengetahui komponen mesin refrigerasi khususnya pembahasan evaporator. Dalam penelitian ini digunakan lemari pendingin (kulkas sederhana untuk pengawetan dan pendinginan bahan makanan dalam rumah tangga. Untuk refrigerant yang digunakan adalah Refrigerant Freon  R – 22 dan  Freon R - 134a sebagai perbandingan dan untuk mengetahui performance evaporator ( COP pada mesin refrigerasi untuk rumah tangga. Lemari pendingin yang dianalisa berukuran tinggi  = 1 m, panjang  = 0,55 m  dan lebar 0,5 m. Temperatur evaporasi = -5°C dan temperature kondensasi = 40°C.

Modified Peng-Robinson Equation of State for Pure and Mixture Refrigerants with R-32,R-125 and R-134a

Science.gov (United States)

Ll, Jin; Sato, Haruki; Watanabe, Koichi

On the basis of critically-evaluated thermodynamic property data among those recently published, a new Peng-Robinson equation of state for the HFC refrigerants,R-32,R-125 and R-134a,has be end eveloped so as to represent the VLE properties in the vapor-liquid coexisting phase at temperatures 223K-323K. In accord with a challenge to correlate the binary and/or ternary interatction parameters as functions of temperature, we have also applied the present modified Peng-Robinson equation of state to the promising alternative HFC refrigerant mixtures, i.e., R-32/125,R-32/134a and R-32/125/134a systems. The developed equation of state improves significantly its effectiveness for practical engineering property calculations at refrigerantion and air-conditioning industries in comparison with conventional Peng-Robinson equation.

High pressure freon decontamination of remote equipment

International Nuclear Information System (INIS)

Wilson, C.E.

1987-01-01

A series of decontamination tests using high pressure FREON 113 was conducted in the 200 Area of the Hanford site. The intent of these tests was to evaluate the effectiveness of FREON 113 in decontamination of manipulator components, tools, and equipment items contaminated with mixed fission products. The test results indicated that high pressure FREON 113 is very effective in removing fissile material from a variety of objects and can reduce both the quantity and the volume of the radioactive waste material presently being buried

Exergetic and thermodynamic comparison of R12 and R134a as vapour compression refrigeration working fluids

Energy Technology Data Exchange (ETDEWEB)

De Rossi, Filippo; Mastrullo, Rita; Mazzei, Pietro [Naples Univ. (Italy)

1993-05-01

A software package for both the computation of thermodynamic properties and the analysis of the usual vapour compression plant schemes is a useful tool for air conditioning and refrigeration researchers and manufacturers. At present, it could make an important contribution to the search for CFC substitutes; in fact, comparisons between two or more working fluids could be accomplished more easily. A program created by the authors is presented by means of some demonstrative diagrams referring to a comparison between the ''ozone killer'' R12 and its substitute R134a. An R134a exergy-enthalpy chart is also provided. (Author)

Volume reduction and material recirculation by freon decontamination

International Nuclear Information System (INIS)

Berners, O.; Buhmann, D.; Yamashita, Y.; Yoshiaki, M.

1989-01-01

This paper discusses the use of freon in a large variety of decontamination in the nuclear and non-nuclear fields. As far as the contamination is loose or smerable, surfaces of nearly all materials can be decontaminated. Freon is electrically non-conductive, chemically neutral and has a low surface tension. So it is capable of creeping under the contaminant and loosening or dissolving it. Used freon can be collected, cleaned and recirculated. Its cleaning can be done easily by evaporation at its lower vapor point of about 48 degrees C (104 degrees F). Good decontamination results could be achieved, expensive materials, tools and equipment could be recirculated. Big volumes of materials could get separated from their contaminants, which is the real radioactive waste. Freon decontamination is an effective, overall economical and approved technology to volume reduction and material recirculation

Future emissions and atmospheric fate of HFC-1234yf from mobile air conditioners in Europe.

Science.gov (United States)

Henne, Stephan; Shallcross, Dudley E; Reimann, Stefan; Xiao, Ping; Brunner, Dominik; O'Doherty, Simon; Buchmann, Brigitte

2012-02-07

HFC-1234yf (2,3,3,3-tetrafluoropropene) is under discussion for replacing HFC-134a (1,1,1,2-tetrafluoroethane) as a cooling agent in mobile air conditioners (MACs) in the European vehicle fleet. Some HFC-1234yf will be released into the atmosphere, where it is almost completely transformed to the persistent trifluoroacetic acid (TFA). Future emissions of HFC-1234yf after a complete conversion of the European vehicle fleet were assessed. Taking current day leakage rates and predicted vehicle numbers for the year 2020 into account, European total HFC-1234yf emissions from MACs were predicted to range between 11.0 and 19.2 Gg yr(-1). Resulting TFA deposition rates and rainwater concentrations over Europe were assessed with two Lagrangian chemistry transport models. Mean European summer-time TFA mixing ratios of about 0.15 ppt (high emission scenario) will surpass previously measured levels in background air in Germany and Switzerland by more than a factor of 10. Mean deposition rates (wet + dry) of TFA were estimated to be 0.65-0.76 kg km(-2) yr(-1), with a maxium of ∼2.0 kg km(-2) yr(-1) occurring in Northern Italy. About 30-40% of the European HFC-1234yf emissions were deposited as TFA within Europe, while the remaining fraction was exported toward the Atlantic Ocean, Central Asia, Northern, and Tropical Africa. Largest annual mean TFA concentrations in rainwater were simulated over the Mediterranean and Northern Africa, reaching up to 2500 ng L(-1), while maxima over the continent of about 2000 ng L(-1) occurred in the Czech Republic and Southern Germany. These highest annual mean concentrations are at least 60 times lower than previously determined to be a safe level for the most sensitive aquatic life-forms. Rainwater concentrations during individual rain events would still be 1 order of magnitude lower than the no effect level. To verify these results future occasional sampling of TFA in the atmospheric environment should be considered. If future HFC-1234yf

Venezuelan contribution to the ozone layer preservation

Energy Technology Data Exchange (ETDEWEB)

Pereira, M.H.; Coltters, R.; Damian, A. [Universidad La Urbina, Caracas (Venezuela). Escuela de Ingenieria Mecanica

1995-12-31

There are two ways to solve the problem of the ozone layer destruction in the upper atmosphere by the harmful chlorine which comes from CFC refrigerants and from aerosols. The first one is to replace the old equipment by new ones which work with non-contaminant refrigerants and the second solution is to establish a conversion program according to the Montreal Protocol and the Vienna Convention. According to this, some Venezuelan Companies are beginning to replace the car`s air conditioning equipment, and others like CVG-SIDOR are making an accelerated program for its central air conditioning system. Another company, C.A. Metro de Caracas, has made a progressive program for the replacement of Freon R-11 and R-12 for HFC 123 and HFC-134a respectively. The results indicate that the most economical solution is to replace these refrigerants instead of replacing the equipment completely.

Survey of the energy use rationalization freon decomposition technology (public use); Energy shiyo gorika freon bunkai gijutsu chosa. (kokaiyo)

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-03-01

The paper made a research survey of a technology to decompose the recovered CFC (specified freon) in which energy efficiency is high and no hazardous materials such as dioxin are generated. As to the technology to decompose specified freon, the high frequency plasma method, the cement kiln method and the combustion method are at the stage of the demonstration test and close to the commercialization. The catalyst method has finished the basic test and is at the stage of a pilot plant. Besides, there are the supercritical water decomposition method, the ultraviolet decomposition method, etc., but they are at the stage of the fundamental research. Mechanisms of the dioxin generation and the suppression of dioxin generation in case of incinerating waste mixed with halide have been made clear. In the fundamental test, conditions were obtained under which the freon decomposition rate of more than 99.99% is attained by the combustion of a mixture of industrial waste and freon using the combustion method, and measures for reduction in hazardous materials such as dioxin were expected to be taken. In the catalyst method, the result obtained was the decomposition rate of more than 99.99% and the catalyst life of more than 1000 years, and its practicality was confirmed. 43 refs., 97 figs., 29 tabs.

HFC-23 (CHF3 emission trend response to HCFC-22 (CHClF2 production and recent HFC-23 emission abatement measures

Directory of Open Access Journals (Sweden)

R. G. Prinn

2010-08-01

Full Text Available HFC-23 (also known as CHF3, fluoroform or trifluoromethane is a potent greenhouse gas (GHG, with a global warming potential (GWP of 14 800 for a 100-year time horizon. It is an unavoidable by-product of HCFC-22 (CHClF2, chlorodifluoromethane production. HCFC-22, an ozone depleting substance (ODS, is used extensively in commercial refrigeration and air conditioning, in the extruded polystyrene (XPS foam industries (dispersive applications and also as a feedstock in fluoropolymer manufacture (a non-dispersive use. Aside from small markets in specialty uses, HFC-23 has historically been considered a waste gas that was, and often still is, simply vented to the atmosphere. Efforts have been made in the past two decades to reduce HFC-23 emissions, including destruction (incineration in facilities in developing countries under the United Nations Framework Convention on Climate Change's (UNFCCC Clean Development Mechanism (CDM, and by process optimization and/or voluntary incineration by most producers in developed countries. We present observations of lower-tropospheric mole fractions of HFC-23 measured by "Medusa" GC/MSD instruments from ambient air sampled in situ at the Advanced Global Atmospheric Gases Experiment (AGAGE network of five remote sites (2007–2009 and in Cape Grim air archive (CGAA samples (1978–2009 from Tasmania, Australia. These observations are used with the AGAGE 2-D atmospheric 12-box model and an inverse method to produce model mole fractions and a "top-down" HFC-23 emission history. The model 2009 annual mean global lower-tropospheric background abundance is 22.6 (±0.2 pmol mol−1. The derived HFC-23 emissions show a "plateau" during 1997–2003, followed by a rapid ~50% increase to a peak of 15.0 (+1.3/−1.2 Gg/yr in 2006. Following this peak, emissions of HFC-23 declined rapidly to 8.6 (+0.9/−1.0 Gg/yr in 2009, the lowest annual emission of the past 15 years. We derive a 1990–2008 "bottom-up" HFC-23 emission history

Component-wise exergy and energy analysis of vapor compression refrigeration system using mixture of R134a and LPG as refrigerant

Science.gov (United States)

Gill, Jatinder; Singh, Jagdev

2017-11-01

In this work, the experimental examination was carried out using a mixture of R134a and LPG refrigerant (consisting of R134a and LPG in a proportion of 28:72 by weight) as a replacement for R134a in a vapor compression refrigeration system. Exergy and energy tests were carried out at different evaporator and condenser temperatures with controlled environmental conditions. The results showed that the exergy destruction in the compressor, condenser, evaporator, and a capillary tube of the R134a / LPG refrigeration system was found lower by approximately 11.13-3.41%, 2.24-3.43%, 12.02-13.47% and 1.54-5.61% respectively. The compressor exhibits the highest level of destruction, accompanied by a condenser, an evaporator and a capillary tube in refrigeration systems. The refrigeration capacity, COP and power consumption of the compressor of the R134a /LPG refrigeration system were detected higher and lower compared to the R134a refrigeration system by about 7.04-11.41%, 15.1-17.82%, and 3.83-8.08% respectively. Also, the miscibility of R134a and LPG blend with mineral oil discovered good. The R134a and LPG refrigerant mixture proposed in this study perform superior to R134a from component-wise exergy and energy analyses under similar experimental conditions.

Component-wise exergy and energy analysis of vapor compression refrigeration system using mixture of R134a and LPG as refrigerant

Science.gov (United States)

Gill, Jatinder; Singh, Jagdev

2018-05-01

In this work, the experimental examination was carried out using a mixture of R134a and LPG refrigerant (consisting of R134a and LPG in a proportion of 28:72 by weight) as a replacement for R134a in a vapor compression refrigeration system. Exergy and energy tests were carried out at different evaporator and condenser temperatures with controlled environmental conditions. The results showed that the exergy destruction in the compressor, condenser, evaporator, and a capillary tube of the R134a / LPG refrigeration system was found lower by approximately 11.13-3.41%, 2.24-3.43%, 12.02-13.47% and 1.54-5.61% respectively. The compressor exhibits the highest level of destruction, accompanied by a condenser, an evaporator and a capillary tube in refrigeration systems. The refrigeration capacity, COP and power consumption of the compressor of the R134a /LPG refrigeration system were detected higher and lower compared to the R134a refrigeration system by about 7.04-11.41%, 15.1-17.82%, and 3.83-8.08% respectively. Also, the miscibility of R134a and LPG blend with mineral oil discovered good. The R134a and LPG refrigerant mixture proposed in this study perform superior to R134a from component-wise exergy and energy analyses under similar experimental conditions.

Gas-Chromatographic Determination Of Water In Freon PCA

Science.gov (United States)

Melton, Donald M.

1994-01-01

Gas-chromatographic apparatus measures small concentrations of water in specimens of Freon PCA. Testing by use of apparatus faster and provides greater protection against accidental contamination of specimens by water in testing environment. Automated for unattended operation. Also used to measure water contents of materials, other than Freon PCA. Innovation extended to development of purgeable sampling accessory for gas chromatographs.

Performance analysis of the electric vehicle air conditioner by replacing hydrocarbon refrigerant

Science.gov (United States)

Santoso, Budi; Tjahjana, D. D. D. P.

2017-01-01

The thermal comfort in passenger cabins needs an automotive air-conditioning system. The electric vehicle air conditioner system is driven by an electric compressor which includes a compressor and an electric motor. Almost air-conditioning system uses CFC-12, CFC-22 and HFC-134a as refrigerant. However, CFC-12 and CFC-22 will damage the ozone layer. The extreme huge global warming potentials (GWP) values of CFC-12, CFC-22, and HFC-134a represent the serious greenhouse effect of Earth. This article shows new experimental measurements and analysis by using a mixture of HC-134 to replace HFC-134a. The result is a refrigerating effect, the coefficient of performance and energy factor increase along with cooling capacity, both for HFC-134a and HC-134. The refrigerating effect of HC-134 is almost twice higher than HFC-134a. The coefficient of performance value of HC-134 is also 36.42% greater than HFC-134a. Then, the energy factor value of HC-134 is 3.78% greater than HFC-134a.

Development of a Centrifugal Technique for the Microbial Bioburden Analysis of Freon (CFC-11)

Science.gov (United States)

Benardini, James N.; Koukol, Robert C.; Kazarians, Gayane A.; Morales, Fabian

2013-01-01

NASA Procedural Requirement 8020.12C entitled "Planetary Protection Provisions for Robotic Extraterrestrial Missions" states that the source-specific encapsulated microbial density for encapsulated organisms (div(0)) in nonmetallic materials ranges from 1-30 spores/cubic cm. The standard laboratory procedure, NASA Standard Procedures for the Microbial Examination of Space Hardware, NHB 5340.1B, does not provide any direction into the methodologies to understand the bioburden within such a fluid as CFC-11 (Freon). This general specification value for the Freon would be applicable to the Freon charged within the Mars Science Laboratory fs (MSL fs) Heat Rejection System. Due to the large volume required to fill this system, MSL could not afford to conservatively allocate 55.8% of the total spore budget of the entire laboratory system (rover, descent stage, cruise stage, and aeroshell) of 5.00 X 10(exp 5) spores at launch. A novel filtration approach was developed to analyze the Freon employing a 50 kDa molecular weight cutoff (MCO) filter, followed by 0.22-micron pore-size filter to establish a calculated microbial bioburden.

Cooling performance of R510A in domestic water purifiers

International Nuclear Information System (INIS)

Park, Ki Jung; Lee, Yo Han; Jung, Dong Soo

2010-01-01

Cooling performance of R510A is examined both numerically and experimentally in an effort to replace HFC134a in the refrigeration system of domestic water purifiers. Although the use of HFC134a is currently dominant, it is being phased out in Europe and most developed countries due to its high potential contribution to global warming. To solve this problem, cycle simulation and experimental measurements are conducted with a new refrigerant mixture of 88%RE170/12%R600a using actual domestic water purifiers. This mixture has been recently numbered and listed as R510A by ASHRAE. Test results show that, due to the small internal volume of the refrigeration system of the domestic water purifiers, system performance with R510A is greatly influenced by the amount of charge. With the optimum charge amount of 20 to 21 g, approximately 50% that of HFC134a, the energy consumption of R510A is 22.3% lower than that of HFC134a. The compressor discharge temperature of R510A is 3.7 .deg. C lower than that of HFC134a at the optimum charge. Overall, R510A, a new, long term, and environmentally safe refrigerant, is a good alternative for HFC134a. Furthermore, it requires only minor changes in the refrigeration system of the domestic water purifiers

Evaluation of high pressure Freon decontamination. I. Preliminary tests

International Nuclear Information System (INIS)

Rankin, W.N.

1983-01-01

High-pressure Freon blasting techniques are being evaluated for applications involving the removal of non-adherent radioactive particulate contamination at SRP. Very little waste is generated by this technique because the used Freon can be easily distilled and reused. One of the principle advantages of this technique is that decontaminated electrical equipment can be returned to service immediately without drying, unlike high-pressure water blasting techniques. Preliminary scoutin tests evaluating high-pressure Freon blasting for decontamination at SRP were carried out at Quadrex Co., Oak Ridge, TN, October 12 and 13. DWPF-type contamination (raw sludge plus volatiles) and separations area-type contamination (diluted boiling point (47.6 0 C) allow it to rapidly separate from higher boiling contaminants via distillation with filtration to remove particulate material, and distillation with condensation, the solvent may be recovered for indefinite reuse while reducing the radioactive waste to a minimum. 3 references, 5 figures, 6 tables

High-pressure viscosity behavior of x 1,1,1,2-tetrafluoroethane (HFC-134a)+(1-x) triethylene glycol dimethylether (TriEGDME) mixtures: Measurements and modeling

DEFF Research Database (Denmark)

Monsalvo, Matias Alfonso; Baylaucq, A.; Cisneros, Sergio

2006-01-01

fractions x(HFC) = 0.3427 and 0.5940 (a total of 100 experimental values). Since lubricants and refrigerants are in two different thermodynamic states at atmospheric pressure and ambient temperature, an especially designed falling-body viscometer has been used to perform the measurements. The data obtained...... with a physical and theoretical background, such as the hard-sphere scheme, the free-volume model, and the friction theory....

On scaling laws for modelling the steam/water flow in a 'Dodewaard' fuel-assembly using Freon-12

International Nuclear Information System (INIS)

Graaf, R. van de; Mudde, R.F.; Hagen, T.H.J.J. van der.

1991-09-01

To stimulate the steam/water flow behaviour in a fuel assembly as present in the boiling water reactor at Dodewaard, Freon-12 is used as a modelling fluid. Scaling criteria are elaborated using dimensional analysis as a fluid-to-fluid modelling technique. When scaling is emphasized on void-fraction distribution and flow-regime transitions it is found that an approximately half-scale geometry for the Freon-model should be used. Together with the low latent heat of vaporization of Freon-12 this reduces the total required heat input significantly to be only 2% of the required heat input in a 'Dodewaard' fuel-assembly. Finally, working pressure (and saturation temperature) can also be brought to a convenient level. (author). 16 refs., 11 figs., 1 tab

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

Science.gov (United States)

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%).

THERMODYNAMIC PROPERTIES OF SELECTED HFC REFRIGERANTS

Science.gov (United States)

Hydrofluorocarbon (HFC) refrigerants are possible alternatives to replace ozone-depleting chlorofluorocarbon and hydrochlorofluorocarbon (HCFC) refrigerants. The flammability of a proposed new refrigerant is a major consideration in assessing its utility for a particular applicat...

Reactions of the radical cations of aliphatic aldehydes in freon matrices

International Nuclear Information System (INIS)

Belevskij, V.N.; Belopushkin, S.I.; Feldman, V.I.

1985-01-01

ESR spectra of γ-irradiated solutions of acetic and propionic aldehydes in freon-11 and freon-113 affected by aldehyde concentration, temperature, and the action of light were studied. It is shown that the radical cations are converted into neutral radicals, and the cations CHsub(3)CHsub(2)CHOsup(+). are converted to RCO and CHsub(3)CHCHO due to ion-molecular reactions of proton transfer of hydrogen atom transfer. (author)

The large contribution of projected HFC emissions to future climate forcing.

Science.gov (United States)

Velders, Guus J M; Fahey, David W; Daniel, John S; McFarland, Mack; Andersen, Stephen O

2009-07-07

The consumption and emissions of hydrofluorocarbons (HFCs) are projected to increase substantially in the coming decades in response to regulation of ozone depleting gases under the Montreal Protocol. The projected increases result primarily from sustained growth in demand for refrigeration, air-conditioning (AC) and insulating foam products in developing countries assuming no new regulation of HFC consumption or emissions. New HFC scenarios are presented based on current hydrochlorofluorocarbon (HCFC) consumption in leading applications, patterns of replacements of HCFCs by HFCs in developed countries, and gross domestic product (GDP) growth. Global HFC emissions significantly exceed previous estimates after 2025 with developing country emissions as much as 800% greater than in developed countries in 2050. Global HFC emissions in 2050 are equivalent to 9-19% (CO(2)-eq. basis) of projected global CO(2) emissions in business-as-usual scenarios and contribute a radiative forcing equivalent to that from 6-13 years of CO(2) emissions near 2050. This percentage increases to 28-45% compared with projected CO(2) emissions in a 450-ppm CO(2) stabilization scenario. In a hypothetical scenario based on a global cap followed by 4% annual reductions in consumption, HFC radiative forcing is shown to peak and begin to decline before 2050.

Experimental investigation of HFC407C/HC290/HC600a mixture in a window air conditioner

International Nuclear Information System (INIS)

Jabaraj, D.B.; Avinash, P.; Lal, D. Mohan; Renganarayan, S.

2006-01-01

HCFC22, one of the widely used refrigerants in window air conditioners must be phased out soon as per the Montreal protocol. Presently, HFC407C is considered as a potential drop in substitute for HCFC22, but retrofitting HCFC22 systems with HFC407C with polyol ester oil (POE) is a major issue as HFC407C is immiscible with mineral oil. The miscibility issue of HFC407C with mineral oil was overcome with the addition of a HC blend to it. The above technoeconomic feasibility issues to retrofit the existing HCFC22 systems with an ozone friendly refrigerant and retain the energy efficiency of the system are challenges in the air conditioning sector. In this present work, an experimental analysis has been conducted in a window air conditioner retrofitted with eco-friendly refrigerant mixtures of HFC407C/HC290/HC600a without changing the mineral oil. Its performance, as well as energy consumption, was compared with the conventional one. It is observed that the mixtures demand lengthening of the condenser in order to maintain the discharge pressure within acceptable limits. This also resulted in better heat transfer at the condenser. Therefore, in this study, the condenser tube length was increased by 19% to suit the mixtures as compared to HCFC22. Compared to HCFC22, the refrigeration capacity of the new mixture was 9.54-12.76% higher than that of HCFC22, while the actual COP was found to be 11.91-13.24% higher than that of HCFC22. The overall performance has proved that the HFC407C/HC blend refrigerant mixture could be an eco-friendly substitute to phase out HCFC22

Experimental study of the structure of vapor phase during boiling of R134a on heat exchange surfaces of heat pump

Science.gov (United States)

Ustinov, D. A.; Sukhikh, A. A.; Sidenkov, D. V.; Ustinov, V. A.

2017-10-01

The heat supply by means of heat pumps is considered now as a rational method of local heating which can lead to economy of primary fuel. At use of low-potential heat, for example, the heat of a ground (5 … 18 °C) or ground waters (8 … 10°C) only small depressing of temperature of these sources (on 3 … 5°C) is possible that demands application of heat exchangers with intensified heatmass transfer surfaces. In thermal laboratory of TOT department the 200 W experimental installation has been developed for research of process of boiling of freon R134a. The principle of action of the installation consists in realisation of reverse thermodynamic cycle and consecutive natural measurement of characteristics of elements of surfaces of heat exchangers of real installations at boiling points of freon from-10°C to +10°C and condensing temperatures from 15°C to 50 °C. The evaporator casing has optical windows for control of process of boiling of freon on ribbed on technology of distorting cut tubes. Temperature measurement in characteristic points of a cycle is provided by copper-constantan thermocouples which by means of ADT are connected to the computer that allows treat results of measurements in a real time mode. The structure of a two-phase flow investigated by means of the optical procedure based on laser technique.

Burnout and intensification of heat transfer in a four-red bundle in freon-12 and water flows

International Nuclear Information System (INIS)

Perepelitsa, N.I.; Pomet'ko, R.S.; Sapankevich, A.P.

1979-01-01

Results of experimental investigation of burnout and intensification of heat transfer in a four-rod bundle in freon-12 and water flows are presented. Experiments are carried out at mass rates of 1000-2500 kg/(m 2 xc), pressures of 6.86-12.74 MPa, coolant temperatures at the channel entry of 240-300 deg C for water and pressures of 1.06-2.46 MPa, temperatures of 20-65 deg C for freon. Pressure at the channel exit, coolant expense and temperature at the channel entry were kept constant during experiments. Burnout was attained by smooth increase of electric power and was fixed by indexes of thermal pairs placed in tubes. The comparison of experimental results for freon-12 and water showed that regularities of burnout arising and dependence of critical heat flux (critical power) on regime parameters are qualitatively similar. The experiments showed that dynamics of burnout development for bundles with standard lattices and with lattice-turbulators is essentially different. In the first case burnout starting was accompanied by sharp change of heat transfer surface temperature. In the second case under similar conditions surface temperature increased smoothly in strict correspondance with conducted power. Data evaluation coefficient of freon-12 burnout is specified to water

Analysis and test of a breadboard cryogenic hydrogen/Freon heat exchanger

Science.gov (United States)

Desjardins, L. F.; Hooper, J.

1973-01-01

System studies required to verify a tube-in-tube cryogenic heat exchanger as optimum for the space shuttle mission are described. Design of the optimum configuration, which could be fabricated from commercially available hardware, is discussed. Finally, testing of the proposed configuration with supercritical hydrogen and Freon 21 is discussed and results are compared with thermal and dynamic analysis.

Hydrofluorocarbon (HFC) Scenarios, Climate Effects and the Montreal Protocol

Science.gov (United States)

Velders, G. J. M.; Fahey, D. W.; Daniel, J. S.

2016-12-01

The Montreal Protocol has reduced the use of ozone-depleting substances by more than 95% from its peak levels in the 1980s. As a direct result the use of hydrofluorocarbons (HFCs) as substitute compounds has increased significantly. National regulations to limit HFC use have been adopted recently in the European Union, Japan and USA, and four proposals have been submitted to amend the Montreal Protocol to substantially reduce growth in HFC use. The Parties of the Montreal Protocol have discussed these proposals during their meetings in 2016. The effects of the national regulations and Montreal Protocol amendment proposals on climate forcings and surface temperatures will be presented. Global scenarios of HFC emissions reach 4.0-5.3 GtCO2-eq yr-1 in 2050, which corresponds to a projected growth from 2015 to 2050 which is 9% to 29% of that for CO2 over the same time period. In 2050, in percent of global HFC emissions, China ( 30%), India and the rest of Asia ( 25%), Middle East and northern Africa ( 10%), and USA ( 10%) are the principal source regions; and refrigeration and stationary air conditioning are the major use sectors. Calculated baseline emissions are reduced by 90% in 2050 by implementing the North America Montreal Protocol amendment proposal. This corresponds to a reduction in surface temperature attributed to HFCs from 0.1 oC to 0.04 oC in 2050 and from 0.3-0.4 oC to 0.02 oC in 2100.

Flow film boiling heat transfer in water and Freon-113

International Nuclear Information System (INIS)

Liu, Qiusheng; Shiotsu, Masahiro; Sakurai, Akira

2002-01-01

Experimental apparatus and method for film boiling heat transfer measurement on a horizontal cylinder in forced flow of water and Freon-113 under pressurized and subcooled conditions were developed. The experiments of film boiling heat transfer from single horizontal cylinders with diameters ranging from 0.7 to 5 mm in saturated and subcooled water and Freon-113 flowing upward perpendicular to the cylinders were carried out for the flow velocities ranging from 0 to 1 m/s under system pressures ranging from 100 to 500 kPa. Liquid subcoolings ranged from 0 to 50 K, and the cylinder surface superheats were raised up to 800 K for water and 400 K for Freon-113. The film boiling heat transfer coefficients obtained were depended on surface superheats, flow velocities, liquid subcoolings, system pressures and cylinder diameters. The effects of these parameters were systematically investigated under wider ranges of experimental conditions. It was found that the heat transfer coefficients are higher for higher flow velocities, subcoolings, system pressures, and for smaller cylinder diameters. The observation results of film boiling phenomena were obtained by a high-speed video camera. A new correlation for subcooled flow film boiling heat transfer was derived by modifying authors' correlation for saturated flow film boiling heat transfer with authors' experimental data under wide subcooled conditions. (author)

Analytical computation of thermodynamic performance parameters of actual vapour compression refrigeration system with R22, R32, R134a, R152a, R290 and R1270

Directory of Open Access Journals (Sweden)

Vali Shaik Sharmas

2018-01-01

Full Text Available The present work focuses on analytical computation of thermodynamic performance of actual vapour compression refrigeration system by using six pure refrigerants. The refrigerants are namely R22, R32, R134a, R152a, R290 and R1270 respectively. A MATLAB code is developed to compute the thermodynamic performance parameters of actual vapour compression system such as refrigeration effect, compressor work, COP, power per ton of refrigeration, compressor discharge temperature and volumetric refrigeration capacity at condensing and evaporating temperatures of 54.4oC and 7.2oC respectively. Analytical results exhibited that COP of both R32 and R134a are 15.95% and 11.71% higher among the six investigated refrigerants. However R32 and R134a cannot be replaced directly into R22 system. This is due to their higher compressor discharge temperature and poor volumetric capacity respectively. The discharge temperature of both R1270 and R290 are lower than R22 by 20-26oC. Volumetric refrigeration capacity of R1270 (3197 kJ/m3 is very close to that of volumetric capacity of R22 (3251 kJ/m3. Both R1270 and R290 shows good miscibility with R22 mineral oil. Overall R1270 would be a suitable ecofriendly refrigerant to replace R22 from the stand point of ODP, GWP, volumetric capacity, discharge temperature and miscibility with mineral oil although its COP is lower.

Results of a photographic study of subcooled forced-convection boiling of high-pressure water and Freon-12

International Nuclear Information System (INIS)

Macbeth, R.V.; Wood, R.W.

1980-06-01

The use of a 'Freon' to model high-pressure boiling water has been employed successfully in a number of applications. A prerequisite in modelling is that a well tried and proven basis for the modelling exists. This is not entirely the situation with subcooled boiling however, since past work had tended to concentrate on bulk boiling conditions. Since many of the questions that arise in the design of subcooled boiling systems are concerned with two-phase flow structure, it was decided to place emphasis on attempting to match photographs of subcooled two-phase conditions in high-pressure water (at 55.2 and 82.7 bar) with those of Freon-12 at the corresponding pressures (8.13 and 12.75 bar). A special test-section was constructed giving visual access to a vapour forming region and to an unheated region into which vapour bubbles were drawn by the flow of subcooled liquid. The photographs obtained show that close similarity of two-phase flow structure exists in water and in Freon at corresponding conditions as determined by a previously established modelling procedure. (U.K.)

Comparative study during condensation of R152 a and R134 a with presence of non-condensable gas inside a vertical tube

Science.gov (United States)

Charef, Adil; Feddaoui, M'barek; Najim, Monssif; Meftah, Hicham

2018-04-01

A computational study of the liquid film condensation from vapour-gas mixtures of HFC refrigerants inside a vertical tube is performed. The external wall of the tube is subjected to constant temperature. The model uses an implicit finite difference method to solve the governing equations for the liquid film and gas flow together including the boundary and interfacial matching conditions. Parametric computations were realised to examine the effects of inlet Reynolds number, tube length, and inlet temperature of the gas mixtures on the condensation mechanism. A comparative study between the results obtained for studied R152 a and R134 a with presence of non-condensable gas is made. The predicted results indicate that the condensation of R152 a-air corresponds to a higher accumulated condensation m c d and local heat transfer coefficient h T when compared to R134 a-air in the same conditions. Increasing the inlet Reynolds number or the tube length improve the condensation. Additionally, lower non-condensable gas in R152 a - a i r substantially enhances the heat and mass exchanges.

EXPERIMENTAL PERFORMANCE OF R134a AND R152a USING MICROCHANNEL CONDENSER

OpenAIRE

Bhatkar, V. W.

2018-01-01

An experimental performance study on vapour compression refrigeration system with R134a and drop in substitute R152a with aluminium microchannel condenser was carried out for condensation temperature of 48°C while evaporation temperature varied from -10 to 15°C. Refrigerant charge of R152a was reduced by 40% over R134a with the microchannel condenser. Performance parameters like work input to the compressor, coefficient of performance, refrigerating capacity, condenser capacity and the produc...

HFC404A vaporisation inside a Brazed Plate Heat Exchanger (BPHE): Comparison with the possible long-term low GWP substitutes HC290 (Propane) and HC1270 (Propylene)

International Nuclear Information System (INIS)

Longo, Giovanni A.; Mancin, Simone; Righetti, Giulia; Zilio, Claudio

2016-01-01

Highlights: • This paper investigates HFC404A vaporisation inside a BPHE. • HC290 and HC1270 exhibit heat transfer coefficients similar to HFC404A. • HC290 and HC1270 exhibit frictional pressure drops higher than HFC404A. • The experimental measurements are complemented with an IR thermography analysis. - Abstract: This paper presents the heat transfer coefficients and the pressure drops measured during HFC404A vaporisation inside a commercial BPHE and the comparison of this data with previous measurements carried out during HC290 (Propane) and HC1270 (Propylene) vaporisation inside the same BPHE and similar operating condition in order to assess the capability of HydroCarbon refrigerants as long-term low GWP substitutes for HFC404A in commercial and industrial refrigeration. Propane and Propylene exhibit boiling heat transfer coefficient very similar and frictional pressure drops higher than to those of HFC404A, therefore, taking into account also their good thermodynamic properties, they seems to be very promising as long-term low GWP substitutes for HFC404A. The HFC404A boiling heat transfer coefficients were also compared with a new model for refrigerant boiling inside BPHE (Longo et al., 2015): the mean absolute percentage deviation between calculated and experimental data is 6.0%. The heat transfer measurements were also complemented with an IR thermography analysis for a better understanding of refrigerant vaporisation heat transfer regime inside a BPHE.

A molecular orbital study on the oxidative decomposition of HFC-32

International Nuclear Information System (INIS)

Mochizuki, Yuji

1999-03-01

A series of ab initio molecular orbital calculations, in which Hartree-Fock, second-order Moeller-Plesset perturbation, density functional (B3LYP and BHandHLYP) levels of theory were used, was performed on the elementary reactions related to the oxidative decomposition of HFC-32 (CH 2 F 2 ) by hydroxyl (OH) radicals in a supercritical water condition (so-called SCWO). The whole process is written as CH 2 F 2 + 4OH → CO 2 + 2H 2 O + 2HF and consists of (1) H abstraction by OH to form H 2 O, (2) OH coupling to C-center, and (3) HF leaving to form C=O bond. Molecular geometries were optimized at each level of theory. The HF leaving was found to be the rate-determining step, but its barrier height was lowered by the reactive solvation with an extra H 2 O. Calculations implied that the SCWO of HFC-32 can proceed efficiently. (author)

Freon Rig design for performing to heat transfer experiments for nuclear reactors fuel bundles

International Nuclear Information System (INIS)

Flores, L.F.V.

1981-01-01

The main features of a Freon Rig design for performing to heat transfer experiments for PWR and BWR fuel bundles, are presented. The project is based on a Freon Rig pressurized at 30 bar with a flow rate up to 80 m 3 /h. The maximum power fed to test sections is of about 420 KW D.C. The rig was designed to use scaling techniques wich would enable a fluid of low latente heat to be used in place of water, thereby reducing the cost of testes. (Author) [pt

New Regional and Global HFC Projections and Effects of National Regulations and Montreal Protocol Amendment Proposals

Science.gov (United States)

Velders, G. J. M.

2015-12-01

Hydrofluorocarbons (HFCs) are used as substitutes for ozone-depleting substances that are being phased out globally under Montreal Protocol regulations. New global scenarios of HFC emissions reach 4.0-5.3 GtCO2-eq yr-1 in 2050, which corresponds to a projected growth from 2015 to 2050 which is 9% to 29% of that for CO2 over the same time period. New baseline scenarios are formulated for 10 HFC compounds, 11 geographic regions, and 13 use categories. These projections are the first to comprehensively assess production and consumption of individual HFCs in multiple use sectors and geographic regions with emission estimates constrained by atmospheric observations. In 2050, in percent of global HFC emissions, China (~30%), India and the rest of Asia (~25%), Middle East and northern Africa (~10%), and USA (~10%) are the principal source regions; and refrigeration and stationary air conditioning are the major use sectors. National regulations to limit HFC use have been adopted recently in the European Union, Japan and USA, and four proposals have been submitted in 2015 to amend the Montreal Protocol to substantially reduce growth in HFC use. Calculated baseline emissions are reduced by 90% in 2050 by implementing the North America Montreal Protocol amendment proposal. Global adoption of technologies required to meet national regulations would be sufficient to reduce 2050 baseline HFC consumption by more than 50% of that achieved with the North America proposal for most developed and developing countries. The new HFC scenarios and effects of national regulations and Montreal Protocol amendment proposals will be presented.

HFC perspectives in air-conditioning and refrigeration; Perspectives HFC en A/C et refrigeration

Energy Technology Data Exchange (ETDEWEB)

Fauvarque, P [ELF Atochem, Centre d` Application de Lavallois, 92 (France)

1998-12-31

This paper is a series of transparencies dealing with the development of substitutes for the replacement of the R-22 refrigerant in air-conditioning systems (R-134a, R-407C, R-410A), and in industrial refrigeration systems of agriculture and food industry (R-134a and R-404A). (J.S.)

HFC perspectives in air-conditioning and refrigeration; Perspectives HFC en A/C et refrigeration

Energy Technology Data Exchange (ETDEWEB)

Fauvarque, P. [ELF Atochem, Centre d`Application de Lavallois, 92 (France)

1997-12-31

This paper is a series of transparencies dealing with the development of substitutes for the replacement of the R-22 refrigerant in air-conditioning systems (R-134a, R-407C, R-410A), and in industrial refrigeration systems of agriculture and food industry (R-134a and R-404A). (J.S.)

Substituting HCFC-22 for HFC-410A: an environmental impact trade-off between the ozone depletion and climate change regimes

Science.gov (United States)

Wang, Z.; Fang, X.; Zhang, J.

2015-12-01

After the phase-out of hydrochlorofluorocarbons (HCFCs) as ozone-depleting substances pursuant to the requirements of the Montreal Protocol, hydrofluorocarbons (HFCs) are worldwide used as substitutes although the bulk of them are potent greenhouse gases (GHGs). Therefore, the alternation may bring side effect on global climate change. The trade-off of its environmental impacts between the ozone depletion and climate change regimes necessitates a quantification of the past and future consumption and emissions of both the original HCFCs and their alternative HFCs. Now a dilemma arise in China's RAC industry that HCFC-22, which has an ozone-depleting potential (ODP) of 0.055, has been replaced by HFC-410A, which is a blended potent GHG from respective 50% HFC-32 and HFC-125 with a global warming potential (GWP) of 1923.5. Here, we present our results of estimates of consumption and emissions of HCFC-22 and HFC-410A from 1994 to 2050. Historic emissions of HCFC-22 contributed to global total HCFCs by 4.0% (3.0%-5.6%) ODP-weighted. Projection under a baseline scenario shows future accumulative emissions of HFC-410A make up 5.9%-11.0% of global GWP-weighted HFCs emissions, and its annual contribution to national overall CO2 emissions can be 5.5% in 2050. This makes HCFC-22 and HFC-410A emissions of significant importance in ozone depletion and climate change regimes. Two mitigation scenarios were set to assess the mitigation performance under the North America Proposal and an accelerated schedule. In practice of international environmental agreement, "alternative to alternative" should be developed to avoid regrettable alternations.

Measurements of Sheath Temperature Profiles in Bruce LVRF Bundles Under Post-Dryout Heat Transfer Conditions in Freon

International Nuclear Information System (INIS)

Guo, Y.; Bullock, D.E.; Pioro, I.L.; Martin, J.

2006-01-01

An experimental program has been completed to study the behaviour of sheath wall temperatures in the Bruce Power Station Low Void Reactivity Fuel (shortened hereafter to Bruce LVRF) bundles under post-dryout (PDO) heat-transfer conditions. The experiment was conducted with an electrically heated simulator of a string of nine Bruce LVRF bundles, installed in the MR-3 Freon heat transfer loop at the Chalk River Laboratories (CRL), Atomic Energy of Canada Limited (AECL). The loop used Freon R-134a as a coolant to simulate typical flow conditions in CANDU R nuclear power stations. The simulator had an axially uniform heat flux profile. Two radial heat flux profiles were tested: a fresh Bruce LVRF profile and a fresh natural uranium (NU) profile. For a given set of flow conditions, the channel power was set above the critical power to achieve dryout, while heater-element wall temperatures were recorded at various overpower levels using sliding thermocouples. The maximum experimental overpower achieved was 64%. For the conditions tested, the results showed that initial dryout occurred at an inner-ring element at low flows and an outer-ring element facing internal subchannels at high flows. Dry-patches (regions of dryout) spread with increasing channel power; maximum wall temperatures were observed at the downstream end of the simulator, and immediately upstream of the mid-bundle spacer plane. In general, maximum wall temperatures were observed at the outer-ring elements facing the internal subchannels. The maximum water-equivalent temperature obtained in the test, at an overpower level of 64%, was significantly below the acceptable maximum temperature, indicating that the integrity of the Bruce LVRF will be maintained at PDO conditions. Therefore, the Bruce LVRF exhibits good PDO heat transfer performance. (authors)

Observations of 1,1-difluoroethane (HFC-152a) at AGAGE and SOGE monitoring stations in 1994-2004 and derived global and regional emission estimates

Science.gov (United States)

Greally, B. R.; Manning, A. J.; Reimann, S.; McCulloch, A.; Huang, J.; Dunse, B. L.; Simmonds, P. G.; Prinn, R. G.; Fraser, P. J.; Cunnold, D. M.; O'Doherty, S.; Porter, L. W.; Stemmler, K.; Vollmer, M. K.; Lunder, C. R.; Schmidbauer, N.; Hermansen, O.; Arduini, J.; Salameh, P. K.; Krummel, P. B.; Wang, R. H. J.; Folini, D.; Weiss, R. F.; Maione, M.; Nickless, G.; Stordal, F.; Derwent, R. G.

2007-03-01

Ground-based in situ measurements of 1,1-difluoroethane (HFC-152a, CH3CHF2) which is regulated under the Kyoto Protocol are reported under the auspices of the AGAGE (Advanced Global Atmospheric Gases Experiment) and SOGE (System of Observation of halogenated Greenhouse gases in Europe) programs. Observations of HFC-152a at five locations (four European and one Australian) over a 10 year period were recorded. The annual average growth rate of HFC-152a in the midlatitude Northern Hemisphere has risen from 0.11 ppt/yr to 0.6 ppt/yr from 1994 to 2004. The Southern Hemisphere annual average growth rate has risen from 0.09 ppt/yr to 0.4 ppt/yr from 1998 to 2004. The 2004 average mixing ratio for HFC-152a was 5.0 ppt and 1.8 ppt in the Northern and Southern hemispheres, respectively. The annual cycle observed for this species in both hemispheres is approximately consistent with measured annual cycles at the same locations in other gases which are destroyed by OH. Yearly global emissions of HFC-152a from 1994 to 2004 are derived using the global mean HFC-152a observations and a 12-box 2-D model. The global emission of HFC-152a has risen from 7 Kt/yr to 28 Kt/yr from 1995 to 2004. On the basis of observations of above-baseline elevations in the HFC-152a record and a consumption model, regional emission estimates for Europe and Australia are calculated, indicating accelerating emissions from Europe since 2000. The overall European emission in 2004 ranges from 1.5 to 4.0 Kt/year, 5-15% of global emissions for 1,1-difluoroethane, while the Australian contribution is negligible at 5-10 tonnes/year, <0.05% of global emissions.

The behaviour of a hybrid compressor and ejector refrigeration system with refrigerants 134a and 142b

Energy Technology Data Exchange (ETDEWEB)

Hernandez, J.I.; Best, R.; Estrada, C.A. [UNAM, Morelos (Mexico). Centro de Investigacion en Energia; Dorantes, R.J. [UAM Azcapotzalco, Reynosa Tamaulipas (Mexico). Dpto. de Energia

2004-09-01

A complete theoretical analysis on the thermodynamic behaviour of a HYbrid Compressor and Ejector Refrigeration System - HYCERS - is carried out. An ejector under optimum performance is employed. Two working fluids were selected: refrigerant 142b (HCFC 142b) which has shown very good characteristics in air conditioning applications of ejector systems and refrigerant 134a (HFC134a) which is widely used in refrigeration applications and readily available in most countries. The variation of the generator and condenser temperatures as well as the intercooler pressure were considered for an evaporator temperature of 10{sup o}C and a unitary cooling capacity of 1 kW. The ideal efficiency, the enthalpy-based coefficient of performance, the exergy efficiency and the supplied energy ratio are obtained. With this information, at a moderate condenser and generator temperature of 30 and 85{sup o}C, respectively, the HYCERS working with R134a had the best operation with a highest coefficient of performance of 0.48 and an exergy efficiency of 0.25. On the other hand, if a higher condenser temperature is imposed, the HYCERS with 142b had its best performance at a higher generator temperature. In selecting a working fluid the ejector subsystem behaviour is determinant in system performance. If a working fluid is badly selected, despite having high entrainment ratios, the system will not function properly. Therefore, the methodology here defined becomes an effective tool for selecting adequate working fluids and optimum system design conditions. Also, the employment of a unitary cooling load allows system scaling at any capacity as it increases linearly. (author)

Future atmospheric abundances and climate forcings from scenarios of global and regional hydrofluorocarbon (HFC) emissions

Science.gov (United States)

Velders, Guus J. M.; Fahey, David W.; Daniel, John S.; Andersen, Stephen O.; McFarland, Mack

2015-12-01

Hydrofluorocarbons (HFCs) are manufactured for use as substitutes for ozone-depleting substances that are being phased out globally under Montreal Protocol regulations. While HFCs do not deplete ozone, many are potent greenhouse gases that contribute to climate change. Here, new global scenarios show that baseline emissions of HFCs could reach 4.0-5.3 GtCO2-eq yr-1 in 2050. The new baseline (or business-as-usual) scenarios are formulated for 10 HFC compounds, 11 geographic regions, and 13 use categories. The scenarios rely on detailed data reported by countries to the United Nations; projections of gross domestic product and population; and recent observations of HFC atmospheric abundances. In the baseline scenarios, by 2050 China (31%), India and the rest of Asia (23%), the Middle East and northern Africa (11%), and the USA (10%) are the principal source regions for global HFC emissions; and refrigeration (40-58%) and stationary air conditioning (21-40%) are the major use sectors. The corresponding radiative forcing could reach 0.22-0.25 W m-2 in 2050, which would be 12-24% of the increase from business-as-usual CO2 emissions from 2015 to 2050. National regulations to limit HFC use have already been adopted in the European Union, Japan and USA, and proposals have been submitted to amend the Montreal Protocol to substantially reduce growth in HFC use. Calculated baseline emissions are reduced by 90% in 2050 by implementing the North America Montreal Protocol amendment proposal. Global adoption of technologies required to meet national regulations would be sufficient to reduce 2050 baseline HFC consumption by more than 50% of that achieved with the North America proposal for most developed and developing countries.

Gas engine driven freon-free heat supply system complying with multiple fuels (eco-energy city project)

Energy Technology Data Exchange (ETDEWEB)

Yagyu, Sumio; Maekawa, Koich; Sugawara, Koich; Hayashida, Masaru; Fujishima, Ichiro; Fukuyama, Yuji; Morikawa, Tomoyuki; Yamato, Tadao; Obata, Norio [Advanced Technology Lab., Kubota Corp., Amagasaki, Hyogo (Japan)

1999-07-01

This paper describes recent results at Kubota to develop a gas engine driven freon-free heat supply system. Utilizing a gas mixture which consists of CO and H{sub 2} supplied from a broad area energy utilization network, the system produces four heat sources (263 K, 280 K, 318 K, and 353 K) for air-conditioning, hot water supply, and refrigeration in a single system. It also conforms to fuel systems that utilize methane and hydrogen. This multi-functional heat supply system is composed of an efficient gas engine (methanol gas engine) and a freon-free heat pump (heat-assisted Stirling heat pump). The heat-assisted Stirling heat pump is mainly driven by engine shaft power and is partially assisted by thermal power provided by engine exhaust heat. By proportioning the two energy sources to match the characteristics of the driving engine, the heat pump is supplied with the maximum share of the original energy fueling the engine. Developing the system will establish freon-free thermal utilization system technology that satisfies both wide heat demands and various fuel systems. (orig.)

Compatibility of manufacturing process fluids with HFC refrigerants and ester lubricants. First draft of final report of part one and quarterly report of part two, January 3, 1994--November 30, 1994

Energy Technology Data Exchange (ETDEWEB)

Cavestri, R.C. [Imagination Resources, Inc., Dublin, OH (United States)

1994-11-01

Included in this report is a compiled partial list of presently used processing materials in the air-conditioning and refrigeration industry and the manufacturers, intended uses, and applications of each. Also listed are the processing materials that have received final acceptance for this contracted study. An analytical methodology discussion is presented, including the final decision and the limitations of said methodology, as well as how to establish a level of confidence in observed immiscible material components in two 32 ISO VG polyolesters: (1) Mobil EAL Arctic 32; and (2) ICI Emkarate RL32H; both with HFC 134a refrigerant solutions.

Action mechanism of hydrogen gas on deposition of HfC coating using HfCl{sub 4}-CH{sub 4}-H{sub 2}-Ar system

Energy Technology Data Exchange (ETDEWEB)

Wang, Yalei, E-mail: yaleipm@csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, 410083 (China); School of Metallurgy and Environment, Central South University, Changsha, 410083 (China); Li, Zehao [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, 410083 (China); Xiong, Xiang, E-mail: xiongx@csu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, 410083 (China); Li, Xiaobin [School of Metallurgy and Environment, Central South University, Changsha, 410083 (China); Chen, Zhaoke; Sun, Wei [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, 410083 (China)

2016-12-30

Highlights: • HfC coatings were deposited on C/C composites by LPCVD using HfCl4-CH4-H2-Ar system. • Action mechanism of H2 on structure and growth behavior of HfC coating was studied. • Increased H2 concentration leads to transformation in growth mechanism of coating. - Abstract: Hafnium carbide coatings were deposited on carbon/carbon composites by low pressure chemical vapor deposition using HfCl{sub 4}-CH{sub 4}-H{sub 2}-Ar system. The microstructure, mechanical and ablation resistance performance of HfC coatings deposited with various H{sub 2} concentrations were investigated. The effect of hydrogen gas on the deposition of HfC coating was also discussed. Results show that all of the deposited coatings are composed of single cubic HfC phase, the hydrogen gas acted as a crucial role in determining the preferred orientation, microstructure and growth behavior of HfC coatings. During the deposition process, the gas phase supersaturation of the reaction species can be controlled by adjusting the hydrogen gas concentration. When deposited with low hydrogen gas concentration, the coating growth was dominated by the nucleation of HfC, which results in the particle-stacked structure of HfC coating. Otherwise, the coating growth was dominated by the crystal growth at high hydrogen gas concentration, which leads to the column-arranged structure of HfC coating. Under the ablation environment, the coating C2 exhibits better configurational stability and ablation resistance. The coating structure has a significant influence on the mechanical and ablation resistance properties of HfC coating.

EVALUASI PENGELOLAAN REFRIGERAN CFC, DAN HFC DENGAN MESIN 3R DAN UJI UNJUK KERJA MESIN PENDINGIN STUDI KASUS PADA BENGKEL AC MOBIL DI DENPASAR - BALI

Directory of Open Access Journals (Sweden)

I MADE RASTA

2015-06-01

Full Text Available CFC refrigerant has been known to be one of causes of ozone layer diminishing and HFC is one of green house gases contributing to global warming through the leak and synthetic refrigerant waste to environment. As a response to the ozone layer diminishment on stratosphere, UNEP, in 1981, through a negotiating process of international stages of development reserve the ozone layer through Wina Convention legalized in March 1985. It was then followed up with Montreal Protocol in September 1987 consisting supervision rules on producing, consuming, and treading ozone damaging materials. The government of Indonesia had ratified the convention through President Decree Number 23 Year 1999. The ozone layer reservation program implementation in Indonesia is facilitated by KLH. Governor of Bali issued Decree Number 523/04-B/HK/2010 on membership restructuring of ozone layer reservation and ozone damaging materials control team work in province of Bali. This research was done in 27 car AC service companies or workshop, which received grant of 3R engine in Denpasar, Bali. The research was dominantly focused on monitoring and evaluation, that is how car AC service company or workshop manage CFC/ R-12 and HFC/R-134a refrigerant at service time using 3R engine that refrigerant does not escape to atmostphere. Cooling machine work procedure test (COP was conducted in laboratory. Research result showed that car AC service company or workshop could manage CFC/ R-12 and HFC /R-l 34a eefctively ( 88,3%. The cooling engine work procedure using CFC /R-12 as the result of 3R engine recovery and recycel resulted in 2,435 while pure CFC/R-12 resulted in 2,54. There were differences in cooling engine work procedure to the use of pure CFC/R-12 refrigerant with that resulted by 3R engine with avarage difference 0,089 or 3,53%.

40 CFR Appendix D to Subpart B of... - SAE J2810 Standard for Recovery Only Equipment for HFC-134a Refrigerant

Science.gov (United States)

2010-07-01

... removed from, motor vehicle air-conditioning systems. 1. Scope The purpose of this SAE Standard is to... 700 Standard or allow for recycling of the recovered refrigerant to SAE J2788 specifications by using... (R-134a) Recovery/Recycling Equipment and Recovery/Recycling/Recharging for Mobile Air-Conditioning...

Evaporation of new refrigerants on tube with improved surfaces. Final report. Appendices: A, B, C, D, E and F; Evaporation de nouveaux refrigerants sur des tubes a surface amelioree. Rapport final. Annexes: A, B, C, D, E et F

Energy Technology Data Exchange (ETDEWEB)

Kattan, N.; Favrat, D.; Thome, J. R.; Nidegger, E.; Zuercher, O. [Ecole Polytechnique Federale, Lab. d` Energetique Industrielle (LENI), Lausanne (Switzerland)

1995-07-15

The substitution of old refrigerants in refrigeration systems, heat pumps and organic Rankine cycles for heat recovery, request a good knowledge of heat transfer properties of substitute fluids. The test measurements in LENI test facility (concentric tubes with water flowing in a counter-current flow) with new refrigerants like HFC134a, HCFC123, R-402A, have established a new data bank with new refrigerants, a comparison with old refrigerants like CFC11, CFC12 CFC/HCFC502 and with existent correlations. Correlations were programmed to calculate and compare heat transfer coefficient during the tests. To develop a new correlation based on flow regimes, a high speed Sony video tape camera is used to observe and identify flow patterns. Important images are captured, digitalized, stored for later analysis and sent to a color plotter. Several flow pattern maps were programmed and compared to flow regimes observed on the test rig. Local flow boiling heat transfer coefficients were measured for HFC134a and HCFC123 evaporating inside a microfin tube. In addition, microheat transfer augmentation relative to plain tube test data was investigated. The presence of oil in the evaporator has an effect on heat transfer coefficient. Local flow boiling heat transfer coefficients were measured for refrigerant HFC134a-oil ester (Mobil EAL Arctic 68). A new thermodynamic approach for modeling mixtures of refrigerants and lubricating oils is developed. A very high accuracy, straight vibrating tube type of density flowmeter is used to measure oil concentrations of flowing HFC134a-oil mixtures. (author) figs., tabs., refs.

40 CFR Appendix E to Subpart B of... - The Standard for Automotive Refrigerant Recycling Equipment Intended for Use With Both CFC-12 and...

Science.gov (United States)

2010-07-01

... Refrigerant Recycling Equipment Intended for Use With Both CFC-12 and HFC-134a E Appendix E to Subpart B of... Appendix E to Subpart B of Part 82—The Standard for Automotive Refrigerant Recycling Equipment Intended for... Intended for Use With Both CFC-12 and HFC-134a Foreword The purpose of this standard is to establish...

Study of thermodynamic properties of HFC refrigerant mixtures for Loretz-cycled niew generation air-conditioning equipment; Lorentz cycle ka shinsedai kucho kikiyo HFC kei kongo reibai no netsu rikigaku seishitsu ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

Watanabe, K; Sato, H [Keio University, Tokyo (Japan). Faculty of Science and Technology

1997-02-01

This paper describes thermodynamic properties of HFC refrigerant mixtures for Lorentz-cycled new generation air-conditioning equipment. Equipment has been completed for simultaneous measurement of density and vapor-liquid equilibrium property, accurate measurement of latent heat of vaporization, and accurate measurement of specific heat at constant pressure in liquid phase. Final adjustment and preliminary measurements are currently conducted. Through analytical investigation using actually measured data of thermodynamic properties of HFC refrigerant mixtures, five state equations were obtained, i.e., modified Peng-Robinson state equation which can reproduce the vapor-liquid equilibrium property of refrigerant mixtures, modified Patel-Teja state equation, Helmholtz function type state equation which is applicable in the whole fluid region of refrigerant mixtures, and so on. An evaluation test equipment has been fabricated as a trial for Lorentz-cycled air-conditioning equipments using HFC refrigerant mixtures, and demonstration test is conducted to confirm the validity. 9 refs., 5 figs.

A comparison between burn-out data for 19-rod cluster test-sections cooled by Freon-12 at 155 lb/in2 (abs), and by water at 1000 lb/in2 in vertical upflow

International Nuclear Information System (INIS)

Stevens, G.F.; Wood, R.W.

1966-01-01

Previous experiments on the Winfrith Freon Rig have produced scaling factors which relate these Freon experiments to the corresponding experiments in water with an accuracy of about 10%. It has also been found that the Freon rig is accurate, economical and easy to use. The scaling factors so obtained have now been tested against data for 19-rod clusters which had previously been tested at Columbia University. This report presents the results of the rod cluster tests in which comparison is made between Freon-12 and water for three test-sections which differ in the means of spacing the individual rods. All the test-sections were heated uniformly with respect to length, but had a radial flux depression of nominally 0.70/1.0. The results provide strong evidence that the scaling factor method using Freon-12 at 155 lb/in 2 (abs) is a useful technique for predicting the behaviour at burn-out of complicated test-sections cooled by boiling water at 1000 lb/in 2 with only one-eighteenth of the power required for the water experiment. In particular, the Freon tests reproduce closely the relative burn-out powers previously measured in water. It has also been found that repeated rebuilding of a nominally unchanged cluster from the same components can produce burn-out powers differing by ± 6%. This new result illustrates the power and value of the Freon technique. (author)

Recent increases in the atmospheric growth rate and emissions of HFC-23 (CHF3) and the link to HCFC-22 (CHClF2) production

Science.gov (United States)

Simmonds, Peter G.; Rigby, Matthew; McCulloch, Archie; Vollmer, Martin K.; Henne, Stephan; Mühle, Jens; O'Doherty, Simon; Manning, Alistair J.; Krummel, Paul B.; Fraser, Paul J.; Young, Dickon; Weiss, Ray F.; Salameh, Peter K.; Harth, Christina M.; Reimann, Stefan; Trudinger, Cathy M.; Steele, L. Paul; Wang, Ray H. J.; Ivy, Diane J.; Prinn, Ronald G.; Mitrevski, Blagoj; Etheridge, David M.

2018-03-01

High frequency measurements of trifluoromethane (HFC-23, CHF3), a potent hydrofluorocarbon greenhouse gas, largely emitted to the atmosphere as a by-product of the production of the hydrochlorofluorocarbon HCFC-22 (CHClF2), at five core stations of the Advanced Global Atmospheric Gases Experiment (AGAGE) network, combined with measurements on firn air, old Northern Hemisphere air samples and Cape Grim Air Archive (CGAA) air samples, are used to explore the current and historic changes in the atmospheric abundance of HFC-23. These measurements are used in combination with the AGAGE 2-D atmospheric 12-box model and a Bayesian inversion methodology to determine model atmospheric mole fractions and the history of global HFC-23 emissions. The global modelled annual mole fraction of HFC-23 in the background atmosphere was 28.9 ± 0.6 pmol mol-1 at the end of 2016, representing a 28 % increase from 22.6 ± 0.4 pmol mol-1 in 2009. Over the same time frame, the modelled mole fraction of HCFC-22 increased by 19 % from 199 ± 2 to 237 ± 2 pmol mol-1. However, unlike HFC-23, the annual average HCFC-22 growth rate slowed from 2009 to 2016 at an annual average rate of -0.5 pmol mol-1 yr-2. This slowing atmospheric growth is consistent with HCFC-22 moving from dispersive (high fractional emissions) to feedstock (low fractional emissions) uses, with HFC-23 emissions remaining as a consequence of incomplete mitigation from all HCFC-22 production.Our results demonstrate that, following a minimum in HFC-23 global emissions in 2009 of 9.6 ± 0.6, emissions increased to a maximum in 2014 of 14.5 ± 0.6 Gg yr-1 and then declined to 12.7 ± 0.6 Gg yr-1 (157 Mt CO2 eq. yr-1) in 2016. The 2009 emissions minimum is consistent with estimates based on national reports and is likely a response to the implementation of the Clean Development Mechanism (CDM) to mitigate HFC-23 emissions by incineration in developing (non-Annex 1) countries under the Kyoto Protocol. Our derived cumulative

Radiation polymerization of tetrafluoroethylene in freon-22

International Nuclear Information System (INIS)

Schnautz, N.G.; Thompson, J.C.

1979-02-01

The radiation-induced solution-polymerization of tetrafluoroethylene in Freon-22 has been investigated over a temperature range of - 62 degrees celcius to 0 degrees celcius. The rate of polymerization for the in-source process was found to be directly propertional to monomer concentration and an activation energy of only 7,66 kj/mole was calculated. The number-average molecular mass of the product PTFE ranged from 2X10 4 to 6X10 4 and was relatively independent of the usual reaction parameters. The rate of postpolymerization was also found to be directly proportional to monomer concentration. The postpolyerization process did not result in any enchancement of the initial PTFE molecular mass [af

New use of ammonia in heat pumps; Nouvelle utilisation de l`ammoniac en pompe a chaleur

Energy Technology Data Exchange (ETDEWEB)

Hivet, B.; Ducruet, C. [Electricite de France, 77 - Moret sur Loing (France). Direction des Etudes et Recherches

1996-12-31

According to simple thermodynamic criteria and to pollution regulations, ammonia and HFC 134a are the only refrigerating fluids that can be used in heat pumps. Ammonia is particularly performing at high condensation temperatures. However, its use has become possible thanks to the use of industrial refrigerating compressors with a maximum operation pressure of 40 bars. Test results confirm the interesting thermal performances of this fluid. A comparison with the HFC 134a refrigerant indicates that ammonia leads to equal or better coefficients of performance for higher volume powers. Two applications taken in the agriculture and food industries are presented. (J.S.)

Global and regional emissions estimates of 1,1-difluoroethane (HFC-152a, CH3CHF2) from in situ and air archive observations

Science.gov (United States)

Simmonds, P. G.; Rigby, M.; Manning, A. J.; Lunt, M. F.; O'Doherty, S.; McCulloch, A.; Fraser, P. J.; Henne, S.; Vollmer, M. K.; Mühle, J.; Weiss, R. F.; Salameh, P. K.; Young, D.; Reimann, S.; Wenger, A.; Arnold, T.; Harth, C. M.; Krummel, P. B.; Steele, L. P.; Dunse, B. L.; Miller, B. R.; Lunder, C. R.; Hermansen, O.; Schmidbauer, N.; Saito, T.; Yokouchi, Y.; Park, S.; Li, S.; Yao, B.; Zhou, L. X.; Arduini, J.; Maione, M.; Wang, R. H. J.; Ivy, D.; Prinn, R. G.

2016-01-01

High frequency, in situ observations from 11 globally distributed sites for the period 1994-2014 and archived air measurements dating from 1978 onward have been used to determine the global growth rate of 1,1-difluoroethane (HFC-152a, CH3CHF2). These observations have been combined with a range of atmospheric transport models to derive global emission estimates in a top-down approach. HFC-152a is a greenhouse gas with a short atmospheric lifetime of about 1.5 years. Since it does not contain chlorine or bromine, HFC-152a makes no direct contribution to the destruction of stratospheric ozone and is therefore used as a substitute for the ozone depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). The concentration of HFC-152a has grown substantially since the first direct measurements in 1994, reaching a maximum annual global growth rate of 0.84 ± 0.05 ppt yr-1 in 2006, implying a substantial increase in emissions up to 2006. However, since 2007, the annual rate of growth has slowed to 0.38 ± 0.04 ppt yr-1 in 2010 with a further decline to an annual average rate of growth in 2013-2014 of -0.06 ± 0.05 ppt yr-1. The annual average Northern Hemisphere (NH) mole fraction in 1994 was 1.2 ppt rising to an annual average mole fraction of 10.1 ppt in 2014. Average annual mole fractions in the Southern Hemisphere (SH) in 1998 and 2014 were 0.84 and 4.5 ppt, respectively. We estimate global emissions of HFC-152a have risen from 7.3 ± 5.6 Gg yr-1 in 1994 to a maximum of 54.4 ± 17.1 Gg yr-1 in 2011, declining to 52.5 ± 20.1 Gg yr-1 in 2014 or 7.2 ± 2.8 Tg-CO2 eq yr-1. Analysis of mole fraction enhancements above regional background atmospheric levels suggests substantial emissions from North America, Asia, and Europe. Global HFC emissions (so called "bottom up" emissions) reported by the United Nations Framework Convention on Climate Change (UNFCCC) are based on cumulative national emission data reported to the UNFCCC, which in turn are based on

Recent increases in the atmospheric growth rate and emissions of HFC-23 (CHF3 and the link to HCFC-22 (CHClF2 production

Directory of Open Access Journals (Sweden)

P. G. Simmonds

2018-03-01

Full Text Available High frequency measurements of trifluoromethane (HFC-23, CHF3, a potent hydrofluorocarbon greenhouse gas, largely emitted to the atmosphere as a by-product of the production of the hydrochlorofluorocarbon HCFC-22 (CHClF2, at five core stations of the Advanced Global Atmospheric Gases Experiment (AGAGE network, combined with measurements on firn air, old Northern Hemisphere air samples and Cape Grim Air Archive (CGAA air samples, are used to explore the current and historic changes in the atmospheric abundance of HFC-23. These measurements are used in combination with the AGAGE 2-D atmospheric 12-box model and a Bayesian inversion methodology to determine model atmospheric mole fractions and the history of global HFC-23 emissions. The global modelled annual mole fraction of HFC-23 in the background atmosphere was 28.9 ± 0.6 pmol mol−1 at the end of 2016, representing a 28 % increase from 22.6 ± 0.4 pmol mol−1 in 2009. Over the same time frame, the modelled mole fraction of HCFC-22 increased by 19 % from 199 ± 2 to 237 ± 2 pmol mol−1. However, unlike HFC-23, the annual average HCFC-22 growth rate slowed from 2009 to 2016 at an annual average rate of −0.5 pmol mol−1 yr−2. This slowing atmospheric growth is consistent with HCFC-22 moving from dispersive (high fractional emissions to feedstock (low fractional emissions uses, with HFC-23 emissions remaining as a consequence of incomplete mitigation from all HCFC-22 production.Our results demonstrate that, following a minimum in HFC-23 global emissions in 2009 of 9.6 ± 0.6, emissions increased to a maximum in 2014 of 14.5 ± 0.6 Gg yr−1 and then declined to 12.7 ± 0.6 Gg yr−1 (157 Mt CO2 eq. yr−1 in 2016. The 2009 emissions minimum is consistent with estimates based on national reports and is likely a response to the implementation of the Clean Development Mechanism (CDM to mitigate HFC-23 emissions by

HEAT TRANSFER EVALUATION OF HFC-236FA IN CONDENSATION AND EVAPORATION

Science.gov (United States)

The report gives results of an evaluation of the shell-side heat transfer performance of hydrofluorocarbon (HFC)-236fa, which is considered to be a potential substitute for chlorofluorocarbon (CFC)-114 in Navy shipboard chillers, for both conventional finned [1024- and 1575-fpm (...

Burnout experiments in freon 12 using different types of orifices to simulate the core grids

International Nuclear Information System (INIS)

Ladeira, L.; Katsaounis, A.; Orlowski, R.; Fulfs, H.; Hofmann, K.

1978-01-01

This paper will report on burnout experiments carried out in freon 12 mainly at steady state and further at mass flow or power transient conditions with annular test sections axially uniformly heating either the inside or both the inside and outside rod. The runs are performed without orifice and using three different types of orifices simulating the reactor spacer grid. An important influence of the flow restriction on burnout position and value is measured. Furthermore, the comparison between the burnout correlations W2, W3, B and W2 and GE and experimental results from the literature using simple test section geometries in water and freon 12 demonstrate, that the accuracy is more or less comparable for both fluids. (orig.) [de

Preparation of HfC single crystals by a floating zone technique

International Nuclear Information System (INIS)

Otani, S.; Tanaka, T.

1981-01-01

HfC single crystals have been prepared using a floating zone technique by controlling the compositions of the initial molten zone and the feed rod. The obtained crystal rods were 6 cm long and 0.9 cm in diameter. The various parts of the crystal rods have nearly constant compositions (C/Hf(ZR) = 0.956-0.977), and do not contain any free carbon. The impurities in the crystal, evaporation product, and starting material were examined by fluorescence X-ray spectroscopy. The refining effect due to evaporation was discussed. (orig.)

MODELING AND DESIGN STUDY USING HFC-236EA AS AN ALTERNATIVE REFRIGERANT IN A CENTRIFUGAL COMPRESSOR

Science.gov (United States)

The report gives results of an investigation of the operation of a centrifugal compressor--part of a chlorofluorocarbon (CFC)-114 chiller installation--with the new refrigerant hydrofluorocarbon (HFC)-236ea, a proposed alternative to CFC-114. A large set of CFC-236ea operating da...

Analysis of a combined Rankine-vapour-compression refrigeration cycle

International Nuclear Information System (INIS)

Aphornratana, Satha; Sriveerakul, Thanarath

2010-01-01

This paper describes a theoretical analysis of a heat-powered refrigeration cycle, a combined Rankine-vapour-compression refrigeration cycle. This refrigeration cycle combines an Organic Rankine Cycle and a vapour-compression cycle. The cycle can be powered by low grade thermal energy as low as 60 deg. C and can produce cooling temperature as low as -10 deg. C. In the analysis, two combined Rankine-vapour-compression refrigeration cycles were investigated: the system with R22 and the system with R134a. Calculated COP values between 0.1 and 0.6 of both the systems were found.

Global and regional emissions estimates of 1,1-difluoroethane (HFC-152a, CH3CHF2 from in situ and air archive observations

Directory of Open Access Journals (Sweden)

P. G. Simmonds

2016-01-01

Full Text Available High frequency, in situ observations from 11 globally distributed sites for the period 1994–2014 and archived air measurements dating from 1978 onward have been used to determine the global growth rate of 1,1-difluoroethane (HFC-152a, CH3CHF2. These observations have been combined with a range of atmospheric transport models to derive global emission estimates in a top-down approach. HFC-152a is a greenhouse gas with a short atmospheric lifetime of about 1.5 years. Since it does not contain chlorine or bromine, HFC-152a makes no direct contribution to the destruction of stratospheric ozone and is therefore used as a substitute for the ozone depleting chlorofluorocarbons (CFCs and hydrochlorofluorocarbons (HCFCs. The concentration of HFC-152a has grown substantially since the first direct measurements in 1994, reaching a maximum annual global growth rate of 0.84 ± 0.05 ppt yr−1 in 2006, implying a substantial increase in emissions up to 2006. However, since 2007, the annual rate of growth has slowed to 0.38 ± 0.04 ppt yr−1 in 2010 with a further decline to an annual average rate of growth in 2013–2014 of −0.06 ± 0.05 ppt yr−1. The annual average Northern Hemisphere (NH mole fraction in 1994 was 1.2 ppt rising to an annual average mole fraction of 10.1 ppt in 2014. Average annual mole fractions in the Southern Hemisphere (SH in 1998 and 2014 were 0.84 and 4.5 ppt, respectively. We estimate global emissions of HFC-152a have risen from 7.3 ± 5.6 Gg yr−1 in 1994 to a maximum of 54.4 ± 17.1 Gg yr−1 in 2011, declining to 52.5 ± 20.1 Gg yr−1 in 2014 or 7.2 ± 2.8 Tg-CO2 eq yr−1. Analysis of mole fraction enhancements above regional background atmospheric levels suggests substantial emissions from North America, Asia, and Europe. Global HFC emissions (so called “bottom up” emissions reported by the United Nations Framework Convention on Climate Change (UNFCCC

Evaporation of new refrigerants on tubes with improved surfaces; Evaporation de nouveaux refrigerants sur des tubes a surface amelioree

Energy Technology Data Exchange (ETDEWEB)

Kattan, N.; Favrat, D.; Thome, J. R.; Nidegger, E.; Zuercher, O. [Ecole Polytechnique Federale, Lab. d` Energetique Industrielle (LENI), Lausanne (Switzerland)

1995-07-15

The substitution of old refrigerants in refrigeration systems, heat pumps and organic Rankine cycles for heat recovery, request a good knowledge of heat transfer properties of substitute fluids. The test measurements in LENI test facility (concentric tubes with water flowing in a counter-current flow) with new refrigerants like HFC134a, HCFC123, R-404A, R-402A, have established a new data bank with new refrigerants, a comparison with old refrigerants like CFC11, CFC12 CFC/HCFC502 and with existent correlations. Correlations were programmed to calculate and compare heat transfer coefficient during the tests. To develop a new correlation based on flow regimes, a high speed Sony video tape camera is used to observe and identify flow patterns. Important images are captured, digitalized, stored for later analysis and sent to a color plotter. Several flow pattern maps were programmed and compared to flow regimes observed on the test rig. Local flow boiling heat transfer coefficients were measured for HFC134a and HCFC123 evaporating inside a microfin tube. In addition, microfin heat transfer augmentation relative to plain tube test data was investigated. The presence of oil in the evaporator has an effect on heat transfer coefficient. Local flow boiling heat transfer coefficients were measured for refrigerant HFC134a-oil ester (Mobil EAL Arctic 68). A new thermodynamic approach for modeling mixtures of refrigerants and lubricating oils is developed. A very high accuracy, straight vibrating tube type of density flowmeter is used to measure oil concentrations of flowing HFC134a-oil mixtures. (author) 28 figs., 25 refs.

Cardiotoxicity of Freon among refrigeration services workers: comparative cross-sectional study

Science.gov (United States)

2009-01-01

Background Freon includes a number of gaseous, colorless chlorofluorocarbons. Although freon is generally considered to be a fluorocarbon of relatively low toxicity; significantly detrimental effects may occur upon over exposure. The purpose of the present study is to investigate whether occupational exposure to fluorocarbons can induce arterial hypertension, myocardial ischemia, cardiac arrhythmias, elevated levels of plasma lipids and renal dysfunction. Methods This comparative cross-sectional study was conducted at the cardiology clinic of the Suez Canal Authority Hospital (Egypt). The study included 23 apparently healthy male workers at the refrigeration services workshop who were exposed to fluorocarbons (FC 12 and FC 22) and 23 likewise apparently healthy male workers (unexposed), the control group. All the participants were interviewed using a pre-composed questionnaire and were subjected to a clinical examination and relevant laboratory investigations. Results There were no significant statistical differences between the groups studied regarding symptoms suggesting arterial hypertension and renal affection, although a significantly higher percentage of the studied refrigeration services workers had symptoms of arrhythmias. None of the workers had symptoms suggesting coronary artery disease. Clinical examination revealed that the refrigeration services workers had a significantly higher mean pulse rate compared to the controls, though no significant statistical differences were found in arterial blood pressure measurements between the two study groups. Exercise stress testing of the workers studied revealed normal heart reaction to the increased need for oxygen, while sinus tachycardia was detected in all the participants. The results of Holter monitoring revealed significant differences within subject and group regarding the number of abnormal beats detected throughout the day of monitoring (p < 0.001). There were no significant differences detected in the

Reproductive and developmental toxicity of hydrofluorocarbons used as refrigerants.

Science.gov (United States)

Ema, Makoto; Naya, Masato; Yoshida, Kikuo; Nagaosa, Ryuichi

2010-04-01

The present paper summarizes data on the reproductive and developmental toxicity of hydrofluorocarbons (HFCs), including pentafluoroethane (HFC-125), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,1-trifluoroethane (HFC-143a), 1,1-difluoroethane (HFC-152a), difluoromethane (HFC-32) and 1,1,1,3,3-pentafluoropropane (HFC-245fa), used as refrigerants, published in openly available scientific literature. No developmental toxicity of HFC-125 was found even at 50,000 ppm in rats or rabbits. Although HFC-134a exhibited no dominant lethal effect or reproductive toxicity in rats, it caused low body weight in pre- and postnatal offspring and slightly retarded skeletal ossification in fetuses at 50,000 ppm in rats. No maternal or developmental toxicity was noted after exposure to HFC-143a even at 40,000 ppm in rats or rabbits or HFC-152a even at 50,000 ppm in rats. HFC-32 is slightly maternally and developmentally toxic at 50,000 ppm in rats, but not in rabbits. HFC-245fa caused decreases in maternal body weight and food consumption at 10,000 and 50,000 ppm and fetal weight at 50 000ppm. No evidence of teratogenicity for these HFCs was noted in rats or rabbits. There is limited information about the reproductive toxicity of these HFCs. Animal studies remain necessary for risk assessments of chemicals because it is difficult to find alternative methods to determine the toxic effects of chemicals. It is required to reduce emissions of organic vapors containing HFCs to reduce the risk of exposure. Copyright 2009 Elsevier Inc. All rights reserved.

FY 2000 report on the survey of the freon recovery/treatment technology for construction use heat insulating materials; 2000 nendo chosa hokokusho. Kenchiku yo dannetsuzai furon kaishu shori gijutsu chosa

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-03-01

An investigational study was made of the quantity of the specified freon remaining in the construction use heat insulating material, the rational method for the recovery/treatment, etc. As to the standardization of the method to analyze the remaining freon quantity, the tube furnace - GC method and the MS method were proposed, and the basic items that can be developed to JIS (Japanese Industrial Standard) were standardized. In the estimation of the remaining freon quantity, the actual state of the use of heat insulating materials was surveyed from the statistics on the start of construction work, survey of the heat insulating area in actual buildings and listening to heat insulation workers/cold store construction companies, etc. Further, the remaining quantity was analyzed of samples collected from various buildings nationwide and by years of completion. As a result, it was found out that, even in samples before 1995, HCFC is used in about 10% and that, in case of limiting to the specified freon (CFC), the freon remaining quantity was more than 1-4 wt% even after a lapse of 30 years. The paper arranged subjects on the freon recovery/treatment in each stage of the life cycle and the required conditions for technology/equipment. (NEDO)

FY1995 study of thermodynamic properties of HFC refrigerant mixtures for Lorentz-cycled new generation air-conditioning equipments; 1995 nendo Lorentz cycle ka shinsedai kucho kikiyo HFC kei kongo reibai no netsurikigaku seishitsu ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

A hydrochlorofluorocarbon (HCFC) refrigerant, R-22, is currently being used almost exclusively as a refrigerant for conventional air-conditioning equipments. Since HCFCs are expected to be banned shortly, it is considered a crucial issue to support R and D of the air-conditioning system Lorentz-cycled with hydrofluorocarbon (HFC) refrigerants mixtures. In the present research project, therefore, it is aimed to reveal some of the essential thermodynamic properties of HFC refrigerant mixtures systematically. On the basis of a series of achievements for the last several years by the present research coordinator and his group regarding thermodynamic properties of single-component and blended HFC refrigerants, we have conducted following three major research programs rather systematically on which no challenges have ever been reported worldwide. Throughout a series of experimental as well as analytical researches performed so as to meet the objectives mentioned above, some novel knowledge and valuable outcomes could be obtained in the present study. (1) Precise measurements of vapor-liquid equilibrium properties with simultaneous determination of densities, latent heats of vaporization, and isobaric specific heat capacities in liquid phase. (2) Analytical studies to establish thermodynamic property modeling. (3) Feasibility study of evaluating the Lorentz-cycled performance. (NEDO)

Zero-ODP Refrigerants for Low Tonnage Centrifugal Chiller Systems

National Research Council Canada - National Science Library

Gui, Fulin

1996-01-01

..., HFC-236cb, HFC-236fa, HFC-245cb, and HFC-254cb, for centrifugal chiller applications. We took into account the thermodynamic properties of the refrigerant and aerodynamic properties of the impeller compression process to this evaluation...

Performance comparison of a refrigerator system using R134a and hydrocarbon refrigerant (HCR134a) with different expansion devices

Science.gov (United States)

Aziz, A.; Izzudin; Mainil, A. K.

2017-09-01

The objective of this study is to compare the performance of refrigerator system using working fluid between R134a refrigerant and HCR134a as hydrocarbon refrigerant for substitution of R134a. The use of capillary tube (CT) 1.5 m with HCR134a showed that slightly better COP than among the others, due to the lower pressure of condenser, conversely thermostatic expansion valve (TEV) showed that better COP than among the others with R134a. COP of CT 1.25 m and CT 1.5 m using HCR134a increase about 42.89% and 18.09% compared to R134a, where the electric current of refrigerator system decrease about 11.63% and 10.98%. However, the COP of HCR134a with CT 2.7 m and TEV were obtained lower than R134a about 16.2% and 17.06% and the use of electric current is higher than R134a about 12.98% and 16.5%. The use of HCR134a provides a higher refrigeration effect than R134a about 66.71%-88.27% for various types of expansion devices. The results confirmed that HCR134a could be an alternative refrigerant for replacement of R134a refrigerant.

A quantitative comparison between burn-out data for water at 1000 lb/in2 and Freon 12 at 155 lb/in2 (abs) uniformly heated round tubes, vertical upflow

International Nuclear Information System (INIS)

Stevens, G.F.; Kirby, G.J.

1964-07-01

An earlier report presented the results of an experimental investigation into forced convection burn-out in Freon 12 (Arcton 12) at 155 lb/in 2 (abs) flowing vertically upwards in uniformly heated round tubes. This work was carried out as part of a programme devised to explore the possibility of developing model techniques for studies of two-phase flow and burn-out in high pressure water. The Freon 12 burn-out data was shown to exhibit qualitative similarity with data for water at 1000 Ib/in 2 , and to bring to light a number of details previously concealed by experimental scatter and inadequate coverage. The object of this paper is to present the results of a quantitative comparison of the Freon 12 data and the available water data, and to discuss the implications of this on the possibility of developing model techniques in the study of burn-out. (author)

Transformations of the radical cations of 1,3-dienes, 1,4-dienes, and cyclopentene as studied by ESR technique in irradiated frozen freon matrices and by spin trapping technique in liquid phase

International Nuclear Information System (INIS)

Shchapin, I.Yu.; Belevskij, V.N.

1996-01-01

Transformations of cation-radicals of 1,3- and 1,4-pentadienes, 2,3-dimethylbutadienes and cyclopentene, formed by X-ray irradiation at 77 K, are studied in the freon-11 and 113 matrices. It is shown that cation-radicals of 1,3-pentadienes in the CFCl 3 matrix at 77 K are regrouped in cyclopentene cation-radicals. There is no such a regrouping in the freon-113 matrix. The 1,4-pentadiene radicals have plane structure in the CFCl 3 matrix and are transformed into pentadienyl radicals in the freon-113 matrix. The cation radicals of dimethylbutadiene in the freon-113 matrix are transformed into end allyl radicals. The cation-radicals of cyclopentene in the freon-113 matrix are transformed at 110 K in cyclic allyl radicals. The radicals formation mechanism is in good agreement with the data, obtained during studies on liquid hydrocarbons, X-irradiated at 293 K in the presence of spin trap of 2.4.6-tri-tert-butylnitrosobenzene

Global and regional emissions estimates of 1,1-difluoroethane (HFC-152a, CH[subscript 3]CHF[subscript 2]) from in situ and air archive observations

OpenAIRE

Prinn, Ronald G.

2015-01-01

High frequency, in situ observations from 11 globally distributed sites for the period 1994–2014 and archived air measurements dating from 1978 onward have been used to determine the global growth rate of 1,1-difluoroethane (HFC-152a, CH[subscript 3]CHF[subscript 2]). These observations have been combined with a range of atmospheric transport models to derive global emission estimates in a top-down approach. HFC-152a is a greenhouse gas with a short atmospheric lifetime of about 1.5 years. Si...

An experimental evaluation of the greenhouse effect in the substitution of R134a with CO2

International Nuclear Information System (INIS)

Aprea, C.; Greco, A.; Maiorino, A.

2012-01-01

This paper addresses the problem of R314a substitution with a natural refrigerant fluid. Attention is devoted to the evaluation of the environmental impact, in terms of greenhouse effect. R134a and R744 (CO 2 ) are compared to one another. The hydrofluorocarbon R134a has a large direct warming impact (GWP), whereas the R744 contribution is negligible. The greenhouse effect is determined by the experimental evaluation of the TEWI index (Total Equivalent Warming Impact) that takes into account both direct and indirect contributions to global warming. This paper compares a commercial R134a refrigeration plant and a prototype R744 system working in a trans-critical cycle. The experimental results clearly show that the latter has a larger TEWI than the system operating with R134a. The indirect contribution to global warming provided by R744 is always greater than that of R134a. This contribution prevails in most cases. Only few operating conditions corresponding to a refrigerating plant working as a classical split system benefits, in terms of greenhouse effect, of the substitution of R134a with R744. -- Highlights: ► A comparison between a classical vapour compression plant and a trans-critical cycle. ► Evaluation of the greenhouse effect in R134a substitution with R744. ► Evaluation of direct and indirect contribution to global warming. ► Minimization of the global warming impact of a R744 transcritical cycle.

Characterization of RPC operation with new environmental friendly mixtures for LHC application and beyond

International Nuclear Information System (INIS)

Guida, R.; Capeans, M.; Mandelli, B.

2016-01-01

The large muon trigger systems based on Resistive Plate Chambers (RPC) at the LHC experiments are currently operated with R134a based mixture. Unfortunately R134a is considered a greenhouse gas with high impact on the enviroment and therefore will be subject to regulations aiming in strongly reducing the available quantity on the market. The immediat effects might be instability on the price and incertitude in the product availability. Alternative gases (HFO-1234yf and HFO-1234ze) have been already identified by industry for specific applications as replacement of R134a. Moreover, HFCs similar to the R134a but with lower global warming potential (GWP) are already available (HFC-245fa, HFC-32, HFC-152a). The present contribution describes the results obtained with RPCs operated with new enviromemtal friendly gases. A particular attention has been addressed to the possibility of maintening the current operation conditions (i.e. currently used applied voltage and front-end electronics) in order to be able to use a new mixture for RPC systems even where the common infrastructure (i.e. high voltage and detector components) cannot be replaced for operation at higher applied voltages.

HfC plasma coating of C/C composites

International Nuclear Information System (INIS)

Boncoeur, M.; Schnedecker, G.; Lulewicz, J.D.

1992-01-01

The surface properties of C/C composites such as hardness and corrosion or erosion resistance can be modified by a ceramic coating applied by plasma torch. The technique of plasma spraying in controlled temperature and atmosphere, that was developed and patented by the CEA, makes it possible to apply coatings to the majority of metals and ceramics without affecting the characteristics of the composite. An example of hard deposit of HfC on a C/C composite is described. The characteristics of the deposit and of the bonding with the C/C composite were studied before and after a heat treatment under vacuum for 2 hours at 1000 C. 2 refs

Photoionization and dissociative photoionization study of HFC-152a using synchrotron radiation

International Nuclear Information System (INIS)

Huang Chaoqun; Wei Lixia; Yang Bin; Yang Rui; Wang Sisheng; Shan Xiaobin; Qi Fei; Zhang Yunwu; Sheng Liusi; Hao Liqing; Zhou Shikang; Wang Zhenya

2006-01-01

Photoionization and dissociative photoionization of HFC-152a have been studied using synchrotron radiation and a reflection time-of-flight mass spectrometry (RTOF-MS). The ionization energy of parent molecule (11.94 ± 0.04 eV) and appearance potentials of various fragment ions have been determined by measuring their photoionization efficiency curves. Energies, symmetry point groups and ground electronic states of neutrals and cations of parent and its fragments have been calculated using GAUSSIAN-03 program with the G3 method. According to the theoretical and experimental results, some dissociation channels and their dissociation energies of CH 3 CHF 2 + have been analyzed. (authors)

HEAT TRANSFER EVALUATION OF HFC-236EA AND CFC-114 IN CONDENSATION AND EVAPORATION

Science.gov (United States)

The report gives results of a heat transfer evaluation of the refrigerants hexafluoropropane (HFC-236ea) and 1,1,2,2-dichloro-tetrafluoroethane (CFC-114). (NOTE: With the mandatory phase-out of chlorofluorocarbons (CFCs), as dictated by the Montreal Protocol and Clean Air Act Ame...

(Vapour + liquid) equilibria of the {1,1-difluoroethane (HFC-152a) + n-butane (HC-600)} system

International Nuclear Information System (INIS)

Im, Jihoon; Lee, Gangwon; Lee, Yong-Jin; Kim, Hwayong

2007-01-01

Binary (vapour + liquid) equilibrium data were obtained for the {1,1-difluoroethane (HFC-152a) + n-butane (HC-600)} system at temperatures from 313.15 K to 363.15 K. These experiments were carried out with a circulating-type apparatus with on-line gas chromatography. The experimental data were correlated well by Peng-Robinson equation of state using the Wong-Sandler mixing rules. This system shows positive azeotropic phase behaviour

Disk-based compression of data from genome sequencing.

Science.gov (United States)

Grabowski, Szymon; Deorowicz, Sebastian; Roguski, Łukasz

2015-05-01

High-coverage sequencing data have significant, yet hard to exploit, redundancy. Most FASTQ compressors cannot efficiently compress the DNA stream of large datasets, since the redundancy between overlapping reads cannot be easily captured in the (relatively small) main memory. More interesting solutions for this problem are disk based, where the better of these two, from Cox et al. (2012), is based on the Burrows-Wheeler transform (BWT) and achieves 0.518 bits per base for a 134.0 Gbp human genome sequencing collection with almost 45-fold coverage. We propose overlapping reads compression with minimizers, a compression algorithm dedicated to sequencing reads (DNA only). Our method makes use of a conceptually simple and easily parallelizable idea of minimizers, to obtain 0.317 bits per base as the compression ratio, allowing to fit the 134.0 Gbp dataset into only 5.31 GB of space. http://sun.aei.polsl.pl/orcom under a free license. sebastian.deorowicz@polsl.pl Supplementary data are available at Bioinformatics online. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

A fundamental equation of state for 1,1-difluoroethane (HFC-152a)

Science.gov (United States)

Tillner-Roth, R.

1995-01-01

A fundamental equation ofstale for HFC-152a ( 1,1-dilluorocthane) is presented covering temperatures between the triple-point temperature ( 154.56 K) and 435 K for pressures up to 311 M Pa. The equation is based on reliable ( p, g, T) data in the range mentioned above. These are generally represented within ±0.1 % of density. Furthermore. experimental values of the vapor pressure, the saturated liquid density, and some isobaric heat capacities in the liquid were included during the correlation process. The new equation of state is compared with experimental data and also with the equation of state developed by Tamatsu et al. Differences between the two equations of state generally result from using different experimental input data. It is shown that the new equation of state allows an accurate calculation of various thermodynamic properties for most technical applications.

ESTUDO TERMODINÂMICO DA APLICAÇÃO DE HIDROCARBONETOS EM SISTEMA DE REFRIGERAÇÃO

Directory of Open Access Journals (Sweden)

Jucélio Gomes da Silva

2010-11-01

Full Text Available Os esforços de pesquisa e desenvolvimento na área de Refrigeração e Ar-Condicionado aplicados ao uso de fluidos refrigerantes naturais não esta associada somente à necessidade de preservação do meio-ambiente em si, mas também apresenta grande importância na necessidade latente do aumento da eficiência energética dos equipamentos. Neste sentido, o presente trabalho trata da avaliação termodinâmica da aplicação de fluidos refrigerantes hidrocarbonetos em um sistema de refrigeração residencial que utiliza o HFC134a como fluido de trabalho. Uma análise teórico-computacional foi desenvolvida para o R134a, propano (R290 e as misturas selecionadas (R290/R600a 60%/40%, R290/R600a/R134a 40%/30%/30% e R600a/R290-GLP 70%/30% no ciclo de refrigeração padrão ASHRAE, utilizando as propriedades termodinâmicas e termofísicas fornecidas pelo software REFPROP 6.0. Os resultados das simulações computacionais foram comparados entre os fluidos para indicação da melhor alternativa ao HFC134a. Neste sentido, pôde-se observar que os hidrocarbonetos reduzem os níveis de pressão no condensador e evaporador, além de menores trabalhos de compressão serem necessários no sistema devido às propriedades termofísicas privilegiadas destes fluidos. A utilização destes fluidos também proporciona uma menor temperatura de descarga do compressor, incrementando a vida útil deste componente de alto valor do sistema.

Critical heat flux and post-critical heat flux performance of a 6-m, 37-element fully segmented bundle cooled by Freon-12

International Nuclear Information System (INIS)

Nickerson, J.R.

1982-05-01

A 6-m, 37-element, electrically heated bundle with full end plate simulation, cooled by Freon-12, has been tested for CHF (critical heat flux) and post-CHF conditions in the MR-3 Freon loop. The bundle was tested in a horizontal attitude and had a uniform axial heat flux distribution and radial heat flux depression. A total of 110 CHF points have been collected over the following range of water equivalent conditions: exit pressure 8.27 - 11.03 MPa, mass flux 1.38 - 8.14 Mg.m -2 .s -1 , inlet subcooling 0 - 500 kJ.kg -1 , outlet quality 10% - 37%. The data have been correlated on both a systems and local conditions basis over a limited mass flux range to within 2.8% rms. Significant CHF increases over smooth bundle results have been observed along with significant CHF improvement over a two end plate bundle simulation in the lower mass flux ranges. A satisfactory axial drypatch spreading correlation has been determined and extensive drypatch wall superheat mapping has been performed

Energy and exergy analyses of a bi-evaporator compression/ejection refrigeration cycle

International Nuclear Information System (INIS)

Geng, Lihong; Liu, Huadong; Wei, Xinli; Hou, Zhonglan; Wang, Zhenzhen

2016-01-01

Highlights: • A bi-evaporator compression/ejection refrigeration cycle was studied experimentally. • Experiments were operated at the same external conditions and cooling capacities. • COP improvement was 16.94–30.59% higher than that of the conventional system. • The exergy efficiency of the R134a cycle was improved by 7.57–28.29%. - Abstract: Aiming to reduce the throttling loss in the vapor compression refrigeration cycle, a bi-evaporator compression/ejection refrigeration cycle (BCERC) using an ejector as the expansion device was experimentally investigated with R134a refrigerant. The effects of the compressor frequency and the operating conditions on the coefficient of performance (COP) and the amount of exergy destruction of each component were studied. The results were compared with that of the conventional vapor compression refrigeration cycle under the same external operating conditions and cooling capacities. Results showed that the refrigeration cycle with an ejector as the expansion device exhibited lower irreversibility for each component and total system in comparison with the conventional vapor compression refrigeration cycle. The COP and the exergy efficiency of the BCERC were higher than that of the conventional system. The COP and exergy efficiency improvements became more significant as the condenser water temperature increased, the evaporator water temperature decreased and the compressor frequency increased. In the BCERC with a constant frequency compressor, the COP and the exergy efficiency could be improved by 16.94–30.59%, 7.57–28.29%, respectively. The COP and the exergy efficiency of the BCERC with a variable frequency compressor could increase by around 32.64% and 23.32%, respectively.

The coulometric electron capture detector and its application to the selected freons in water and air. Part of a coordinated programme on the analysis of organic compounds by electron capture gas chromatography

International Nuclear Information System (INIS)

Lasa, J.

1981-01-01

In developing the use of Freon-11 and Freon-12 as environmental tracers in aeronomy, oceanography and hydrology electron capture gas chromatography was used to measure the concentration changes. A detector in the coulometric mode was designed and operated as a solute switch. The detection limit was in the order of 0.2x10 -12 g for a modified head space method in handling aqueous samples. Theoretical analysis of the detector design and the effects of factors including pulsing period, flowrates of carrier gas and the radioactivity of the detector source were discussed and confirmed experimentally

Transmission design in a multimode HFC network

Science.gov (United States)

Cambron, G. Keith

1996-11-01

Contemporary hybrid fiber coaxial (HFC) networks are capable of supporting a wide range of services including traditional analog video, telephony, digital video, and data services. Each service has unique performance or service requirements. This contribution examines transmission design for one such network. Pacific Bell's advanced communications network (ACN). The design methodology begins with a set of end to end service quality objectives. Network impairments, such as noise, distortion and delay, are allocated across the network elements using a set of standard network models. These models are a representative set of the actual field designs and bound the network operating parameters. Network components, headend equipment, and customer premises equipment are specified analytically or characterized empirically in relationship to the chosen impairment set. The component parameters are then included in analytical models to estimate overall network performance. In addition to the forward path transmission considerations examined by traditional coaxial network designers, other dimensions including power consumption, traffic demand, and message latency are taken into account. Analytical models are used to estimate the effects of multiple modulation schemes within the unified network. The variability introduced by on demand services such as telephony and interactive digital services changes the base computational domain from deterministic models to stochastic ones. These models are then used to set operating parameters at measurable points throughout the network for proof of performance prior to turn up, and for ongoing performance monitoring. For closure, empirical results are compared with model projections as a way of verifying and improving the predictive models.

Burnout experiments in freon 12 using different types of orifices to simulate the core grids - comparision between measured and predicted burnout values

International Nuclear Information System (INIS)

Katsaounis, A.; Orlowski, R.; Fulfs, H.; Hofmann, K.; Ladeira, L.C.D.

1978-06-01

This paper will report on burnout experiments carried out in freon 12 mainly at steady state and further at mass flow or power transient conditions with annular test sections axially uniformly heating either the inside or both the inside and outside rod. The runs are performed without orifice and using three different types of orifices simulating the reactor spacer grid. An important influence of the flow restriction on burnout position and value is measured. Furthermore, the comparison between the burnout correlations W2, W3, BandW2 and GE and experimental results from the literature using simple test section geometries in water and freon 12 demonstrate, that the accuracy is more or less comparable for both fluids

Emission estimates of HCFCs and HFCs in California from the 2010 CalNex study

Science.gov (United States)

Barletta, Barbara; Carreras-Sospedra, Marc; Cohan, Alex; Nissenson, Paul; Dabdub, Donald; Meinardi, Simone; Atlas, Elliot; Lueb, Rich; Holloway, John S.; Ryerson, Thomas B.; Pederson, James; VanCuren, Richard A.; Blake, Donald R.

2013-02-01

The CalNex 2010 (California Research at the Nexus of Air Quality and Climate Change) study was designed to evaluate the chemical composition of air masses over key source regions in California. During May to June 2010, air samples were collected on board a National Oceanic and Atmospheric Administration (NOAA) WP-3D aircraft over the South Coast Air Basin of California (SoCAB) and the Central Valley (CV). This paper analyzes six effective greenhouse gases—chlorodifluoromethane (HCFC-22), 1,1-dichloro-1-fluoroethane (HCFC-141b), 1-chloro-1,1-difluoroethane (HCFC-142b), 2-chloro-1,1,1,2-tetrafluoroethane (HCFC-124), 1,1,1,2-tetrafluoroethane (HFC-134a), and 1,1-difluoroethane (HFC-152a)—providing the most comprehensive characterization of chlorofluorocarbon (CFC) replacement compound emissions in California. Concentrations of measured HCFCs and HFCs are enhanced greatly throughout the SoCAB and CV, with highest levels observed in the SoCAB: 310 ± 92 pptv for HCFC-22, 30.7 ± 18.6 pptv for HCFC-141b, 22.9 ± 2.0 pptv for HCFC-142b, 4.86 ± 2.56 pptv for HCFC-124, 109 ± 46.4 pptv for HFC-134a, and 91.2 ± 63.9 pptv for HFC-152a. Annual emission rates are estimated for all six compounds in the SoCAB using the measured halocarbon to carbon monoxide (CO) mixing ratios and CO emissions inventories. Emission rates of 3.05 ± 0.70 Gg for HCFC-22, 0.27 ± 0.07 Gg for HCFC-141b, 0.06 ± 0.01 Gg for HCFC-142b, 0.11 ± 0.03 Gg for HCFC-124, 1.89 ± 0.43 Gg for HFC-134a, and 1.94 ± 0.45 Gg for HFC-152b for the year 2010 are calculated for the SoCAB. These emissions are extrapolated from the SoCAB region to the state of California using population data. Results from this study provide a baseline emission rate that will help future studies determine if HCFC and HFC mitigation strategies are successful.

Burnout in the boiling of water and freon-113 on tubes with annular fins

International Nuclear Information System (INIS)

Rubin, I.R.; Pul'kin, I.N.; Roizen, L.I.

1986-01-01

This paper presents the results of numerical calculations of burnout heat flux associated with the boiling of Freon-113 and water on an annular fin of constant thickness which have been approximated by simple analytical relations. These are used to calculate the critical burnout parameters of tubes with an annular fin assembly. The calculated data may be used for the analysis of tubes with an annular fin assembly over a wide range of variation of the thermophysical properties of the material and geometrical parameters of the fin assembly

National technical report (Matsushita Electric Industrial Company), Vol. 41, No. 3, June 1995. Special issue on environmental technologies

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-06-01

;Contents: Preface to Special Issue on Environmental Technologies; Total System for Recycling and Optimal Treatment of Waste Home Electric Appliances; Material Reduction Design Using Computer Aided Engineering; Rewritable Thermal Recording Sheet; Reusable Taping System; Estimating Method for Disassembly of Home Appliances; Thermal Design Technique to Reduce Furnace Running Cost to Half; Study of Air Conditioner Using HFC Refrigerant Blend; High-Efficiency Compact Rotary Compressor Using New Refrigerant HFC 134a for Automotive Air Conditioner; Simulation for Refrigerators Using HFC 134a; Zero-ODP (Ozone Depletion Potential) Rigid Insulation Foams for Refrigerators; Heat Energy of Industrial Waste Combustion Gas Utilization System; Exhaust Gas Denitrification System for Car Road Tunnels and Underground Parking Areas; Apparatus for Regenerating Diesel Particulate Filter Using Microwave; Analysis of Advanced Treatment System of Heavy Metals in Waste Water; Ventilating and Air-Conditioning System for Energy-Saving Houses; Garbage Disposer; and Anti-Microbial Resin and Applications to Products in Harmony with Living Environment.

The effect of diameter on vertical and horizontal flow boiling crisis in a tube cooled by Freon-12

International Nuclear Information System (INIS)

Merilo, M.; Ahmad, S.Y.

1979-03-01

The influence of test section orientation and diameter on flow boiling crisis occurring in tubes has been studied experimentally using Freon-12 as a coolant. At low mass flux the critical heat flux (CHF) was lower in horizontal flow than in vertical. As either the liquid or vapour velocity, or both, were increased the vertical and horizontal CHF results converged. Above a mass flux of 4 Mg.m -2 .s -1 the results were essentially identical. The effect of tube diameter on boiling crisis in general depends crucially on the parameters which are maintained constant when the comparison is made. (author)

HEAT TRANSFER EVALUATION OF HFC-236EA WITH HIGH PERFORMANCE ENHANCED TUBES IN CONDENSATION AND EVAPORATION

Science.gov (United States)

The report gives results of an evaluation of the heat transfer performance of pure hydrofluorocarbon (HFC)-236ea for high performance enhanced tubes which had not been previously used in Navy shipboard chillers. Shell-side heat transfer coefficient data are presented for condensa...

Non azeotrope mixing refrigerating fluids condensation outside of an horizontal tubes stack; Condensation de melanges non azeotropes de fluides frigorigenes a l'exterieur d'un faisceau de tubes horizontaux

Energy Technology Data Exchange (ETDEWEB)

Signe, J.Ch.

1999-04-16

The development of non-azeotrope mixing, as regular refrigerating fluids substitute, calls in question the experience for the design of refrigerating and cooling machinery. Studies to better understand these fluids behaviour are necessary. The aim of this thesis is the knowledge enlargement on the pure fluids and non azeotrope mixing condensation, outside of a tubes stack, and to simulate the heat transfers. The tubes stack is a condenser, type TEMA X often used in refrigerating machinery. The binary mixing HFC 134a-HFC23, allows a large sliding scale. (A.L.B.)

On-site study of HCFC-22 substitution for HFC non-azeotropic blends (R417A, R422D) on a water chiller of a centralized HVAC system

Energy Technology Data Exchange (ETDEWEB)

Torrella, E.; Larumbe, J.A. [Polytechnic University of Valencia, Dep. of Applied Thermodynamics, Camino de Vera 14, E-46022 Valencia (Spain); Cabello, R.; Sanchez, D.; Llopis, R. [Jaume I University, Dep. of Mechanical Engineering and Construction, Campus de Riu Sec s/n, E-12071 Castellon (Spain)

2010-09-15

The European Regulation no 2037/2000 has banned manufacturing HCFC refrigerants from January 1st 2010, although its use is allowed up to 2015 if the fluids come from a recycling process. This situation creates the need for developing new working fluids to replace the HCFC in the refrigeration plants now in operation. Among all the HCFCs the R22 is the most widely used in a wide range of applications, especially in air conditioning. This work presents an on-site experimental study of the R22 replacement by two possible substitutes, the HFC-417A and the HFC-422D, in a water chiller in which the energy performance was evaluated. This chiller is part of the centralized HVAC system of a lecture room building at the Jaume I University of Castellon, Spain. This communication compares and analyses main operation parameters of the chiller when operating with each refrigerant in real conditions. (author)

Depicting mass flow rate of R134a /LPG refrigerant through straight and helical coiled adiabatic capillary tubes of vapor compression refrigeration system using artificial neural network approach

Science.gov (United States)

Gill, Jatinder; Singh, Jagdev

2018-07-01

In this work, an experimental investigation is carried out with R134a and LPG refrigerant mixture for depicting mass flow rate through straight and helical coil adiabatic capillary tubes in a vapor compression refrigeration system. Various experiments were conducted under steady-state conditions, by changing capillary tube length, inner diameter, coil diameter and degree of subcooling. The results showed that mass flow rate through helical coil capillary tube was found lower than straight capillary tube by about 5-16%. Dimensionless correlation and Artificial Neural Network (ANN) models were developed to predict mass flow rate. It was found that dimensionless correlation and ANN model predictions agreed well with experimental results and brought out an absolute fraction of variance of 0.961 and 0.988, root mean square error of 0.489 and 0.275 and mean absolute percentage error of 4.75% and 2.31% respectively. The results suggested that ANN model shows better statistical prediction than dimensionless correlation model.

High-global warming potential F-gas emissions in California: comparison of ambient-based versus inventory-based emission estimates, and implications of refined estimates.

Science.gov (United States)

Gallagher, Glenn; Zhan, Tao; Hsu, Ying-Kuang; Gupta, Pamela; Pederson, James; Croes, Bart; Blake, Donald R; Barletta, Barbara; Meinardi, Simone; Ashford, Paul; Vetter, Arnie; Saba, Sabine; Slim, Rayan; Palandre, Lionel; Clodic, Denis; Mathis, Pamela; Wagner, Mark; Forgie, Julia; Dwyer, Harry; Wolf, Katy

2014-01-21

To provide information for greenhouse gas reduction policies, the California Air Resources Board (CARB) inventories annual emissions of high-global-warming potential (GWP) fluorinated gases, the fastest growing sector of greenhouse gas (GHG) emissions globally. Baseline 2008 F-gas emissions estimates for selected chlorofluorocarbons (CFC-12), hydrochlorofluorocarbons (HCFC-22), and hydrofluorocarbons (HFC-134a) made with an inventory-based methodology were compared to emissions estimates made by ambient-based measurements. Significant discrepancies were found, with the inventory-based emissions methodology resulting in a systematic 42% under-estimation of CFC-12 emissions from older refrigeration equipment and older vehicles, and a systematic 114% overestimation of emissions for HFC-134a, a refrigerant substitute for phased-out CFCs. Initial, inventory-based estimates for all F-gas emissions had assumed that equipment is no longer in service once it reaches its average lifetime of use. Revised emission estimates using improved models for equipment age at end-of-life, inventories, and leak rates specific to California resulted in F-gas emissions estimates in closer agreement to ambient-based measurements. The discrepancies between inventory-based estimates and ambient-based measurements were reduced from -42% to -6% for CFC-12, and from +114% to +9% for HFC-134a.

A binary mixture operated heat pump

International Nuclear Information System (INIS)

Hihara, E.; Saito, T.

1991-01-01

This paper evaluates the performance of possible binary mixtures as working fluids in high- temperature heat pump applications. The binary mixtures, which are potential alternatives of fully halogenated hydrocarbons, include HCFC142b/HCFC22, HFC152a/HCFC22, HFC134a/HCFC22. The performance of the mixtures is estimated by a thermodynamic model and a practical model in which the heat transfer is considered in heat exchangers. One of the advantages of binary mixtures is a higher coefficient of performance, which is caused by the small temperature difference between the heat-sink/-source fluid and the refrigerant. The mixture HCFC142b/HCFC22 is promising from the stand point of thermodynamic performance

Emissions of halocarbons from mobile vehicle air conditioning system in Hong Kong.

Science.gov (United States)

Yan, H H; Guo, H; Ou, J M

2014-08-15

During the implementation of Montreal Protocol, emission inventories of halocarbons in different sectors at regional scale are fundamental to the formulation of relevant management strategy and inspection of the implementation efficiency. This study investigated the emission profile of halocarbons used in the mobile vehicle air conditioning system, the leading sector of refrigeration industry in terms of the refrigerant bank, market and emission, in the Hong Kong Special Administrative Region, using a bottom-up approach developed by 2006 IPCC Good Practice Guidance. The results showed that emissions of CFC-12 peaked at 53 tons ODP (Ozone Depletion Potential) in 1992 and then gradually diminished, whereas HFC-134a presented an increasing emission trend since 1990s and the emissions of HFC-134a reached 65,000 tons CO2-equivelant (CO2-eq) by the end of 2011. Uncertainty analysis revealed relatively high levels of uncertainties for special-purpose vehicles and government vehicles. Moreover, greenhouse gas (GHG) abatements under different scenarios indicated that potential emission reduction of HFC-134a ranged from 4.1 to 8.4 × 10(5)tons CO2-eq. The findings in this study advance our knowledge of halocarbon emissions from mobile vehicle air conditioning system in Hong Kong. Copyright © 2014 Elsevier B.V. All rights reserved.

The optimum intermediate pressure of two-stages vapor compression refrigeration cycle for Air-Conditioning unit

Science.gov (United States)

Ambarita, H.; Sihombing, H. V.

2018-03-01

Vapor compression cycle is mainly employed as a refrigeration cycle in the Air-Conditioning (AC) unit. In order to save energy, the Coefficient of Performance (COP) of the need to be improved. One of the potential solutions is to modify the system into multi-stages vapor compression cycle. The suitable intermediate pressure between the high and low pressures is one of the design issues. The present work deals with the investigation of an optimum intermediate pressure of two-stages vapor compression refrigeration cycle. Typical vapor compression cycle that is used in AC unit is taken into consideration. The used refrigerants are R134a. The governing equations have been developed for the systems. An inhouse program has been developed to solve the problem. COP, mass flow rate of the refrigerant and compressor power as a function of intermediate pressure are plotted. It was shown that there exists an optimum intermediate pressure for maximum COP. For refrigerant R134a, the proposed correlations need to be revised.

Energy and exergy analysis of LPG (liquefied petroleum gas) as a drop in replacement for R134a in domestic refrigerators

International Nuclear Information System (INIS)

El-Morsi, Mohamed

2015-01-01

This study presents a comparison of energetic and exergetic performance of a vapour compression refrigeration system using pure HC (hydrocarbon) refrigerants. In this study, three different pure HCs propane (R290), butane (R600) and commercial LPG (liquefied petroleum gas) are used in the theoretical analysis. R134a is also used in the analysis as a reference refrigerant. The evaporator temperature ranges from −30 to 0 °C while the condenser ranges from 30 to 50 °C. MATLAB software is used for solving the thermodynamic equations, while the thermo-physical properties are calculated using REFPROP software. The results show that R600 has the highest COP c and exergetic efficiency, while LPG has the lowest. When compared to R134a, the COP c for R134a is higher than that for LPG by 10%. Also, the exergetic efficiency is higher by 5%. However, LPG has the advantage of being not expensive, available in large amounts and zero ozone depletion potential and low global warming potential. - Highlights: • The results show that R600 has the highest COP c & exergy efficiency, and the lowest irreversibility. • LPG has the lowest COP c & exergy efficiency, and the highest irreversibility. • Compared to R134a, LPG has a lower COP c and exergy efficiency by an average of 10% and 5%, respectively

Evaluation of stratospheric age of air from CF4, C2F6, C3F8, CHF3, HFC-125, HFC-227ea and SF6; implications for the calculations of halocarbon lifetimes, fractional release factors and ozone depletion potentials

Science.gov (United States)

Leedham Elvidge, Emma; Bönisch, Harald; Brenninkmeijer, Carl A. M.; Engel, Andreas; Fraser, Paul J.; Gallacher, Eileen; Langenfelds, Ray; Mühle, Jens; Oram, David E.; Ray, Eric A.; Ridley, Anna R.; Röckmann, Thomas; Sturges, William T.; Weiss, Ray F.; Laube, Johannes C.

2018-03-01

In a changing climate, potential stratospheric circulation changes require long-term monitoring. Stratospheric trace gas measurements are often used as a proxy for stratospheric circulation changes via the mean age of air values derived from them. In this study, we investigated five potential age of air tracers - the perfluorocarbons CF4, C2F6 and C3F8 and the hydrofluorocarbons CHF3 (HFC-23) and HFC-125 - and compare them to the traditional tracer SF6 and a (relatively) shorter-lived species, HFC-227ea. A detailed uncertainty analysis was performed on mean ages derived from these new tracers to allow us to confidently compare their efficacy as age tracers to the existing tracer, SF6. Our results showed that uncertainties associated with the mean age derived from these new age tracers are similar to those derived from SF6, suggesting that these alternative compounds are suitable in this respect for use as age tracers. Independent verification of the suitability of these age tracers is provided by a comparison between samples analysed at the University of East Anglia and the Scripps Institution of Oceanography. All five tracers give younger mean ages than SF6, a discrepancy that increases with increasing mean age. Our findings qualitatively support recent work that suggests that the stratospheric lifetime of SF6 is significantly less than the previous estimate of 3200 years. The impact of these younger mean ages on three policy-relevant parameters - stratospheric lifetimes, fractional release factors (FRFs) and ozone depletion potentials - is investigated in combination with a recently improved methodology to calculate FRFs. Updates to previous estimations for these parameters are provided.

Effect of orientation on critical heat flux in a 3-rod bundle cooled by Freon-12

International Nuclear Information System (INIS)

Dimmick, G.R.

1979-06-01

Critical heat flux measurements have been made in a segmented 3-rod test section cooled by Freon-12. Three test section orientations were used: vertical, inclined at 11 deg to the vertical, and horizontal. It was found that at flows of less than 2.5 Mg.m -2 .s -1 the transverse gravity force on the inclined and horizontal orientations reduced the magnitude of the critical heat flux and also changed the location of initial dryout when compared to the vertical data. To account for the effect of orientation during correlation of the data, the Reynolds number was modified to include a transverse gravity term. The minimum standard deviation for the data from the three orientations combined was 3.4 percent and less than 3.7 percent for the three orientations separately. (author)

The performance of solar heat pump with non-freon refrigerant CF{sub 3}CH{sub 2}F(R-134a) for school classroom heating [II

Energy Technology Data Exchange (ETDEWEB)

Sun, K.H.; Jung, H.C. [Kyung Hee University, Seoul (Korea, Republic of); Kim, K.S. [Daebul University (Korea, Republic of)

1997-03-01

The goal of this paper is to measure and compare the performance of solar heat pump for school classroom heating. To accomplish the goal, solar heat pump with aluminum roll bond type evaporator and indoor heat exchanger(condenser) was built and fully instrumented with thermocouples and pressure transducers etc. The test results showed that the COP and capacity of R-134a(CF{sub 3}CH{sub 2}F) were higher than those of R-12(CF{sub 2}Cl{sub 2}). The solar heat pump system for room heating was designed to show the best efficiency that the room temperature make 18{approx}20{sup o} C and 23{approx}25{sup o} C in Seoul during November, December, and January. (author) 12 refs., 4 figs., 2 tabs.

Technical–economic analysis of including wind farms and HFC to solve hybrid TNEM–RPM problem in the deregulated environment

International Nuclear Information System (INIS)

Shayeghi, H.; Hashemi, Y.

2014-01-01

Highlights: • Capability of wind farms is contributed in the problem of hybrid TNEM–RPM. • Inclusion of HFC as a novel and versatile device to implement hybrid TNEM–RPM. • INSGA-II optimization and FDM method is applied to specify the best solution. • Simulation study is conducted on the real power system of Iran. - Abstract: This paper addresses a mathematical model for solving transmission network expansion management (TNEM) associated with reactive power management (RPM) in the presence of double-fed induction generator (DFIG) variable speed wind turbine and hybrid flow controller (HFC). According to this plan, the reactive power capability of DFIG wind turbine is gained and the constraints of deliverable power are derived for each operation point. Strong control capability of the HFC with controlling bus voltage and line power flow offers a great potential for solving many of the problems facing electric utilities. For a precise steady-state analysis of HFC, the injection model is considered which it is an adaptive model in steady-state analysis. The main goals of the proposed management strategy are to minimize investment cost, real power loss cost in transmission lines and voltage deviation and maximize voltage stability index and social benefit at the same time. A three-stage scheme has been developed for solving hybrid TNEM–RPM problem. In the beginning of the plan, it is assumed that all the reactive demands are acquired from local sources and an optimal transmission plan is specified. After transmission lines are constructed, in the second step, reactive power sources will be allocated to weak buses. In order to assess reliability of the system, EENS criterion is used. Due to multi-objective nature of the proposed management method, an improved non-dominated sorting genetic algorithm-II (INSGA-II) style is applied for an optimization procedure. Also, a decision making method based on fuzzy decision making (FDM) is used for finding the best

Dimension reduction for compressible viscous fluids

Czech Academy of Sciences Publication Activity Database

Bella, P.; Feireisl, Eduard; Novotný, A.

2014-01-01

Roč. 134, č. 1 (2014), s. 111-121 ISSN 0167-8019 R&D Projects: GA ČR GA13-00522S Institutional support: RVO:67985840 Keywords : compressible Navier-Stokes system * dimension reduction * thin rod Subject RIV: BA - General Mathematics Impact factor: 1.047, year: 2014 http://link.springer.com/article/10.1007%2Fs10440-014-9872-5

Performance characteristics of low global warming potential R134a alternative refrigerants in ejector-expansion refrigeration system

Directory of Open Access Journals (Sweden)

Mishra Shubham

2016-12-01

Full Text Available Performance assessment of ejector-expansion vapor compression refrigeration system with eco-friendly R134a alternative refrigerants (R152a, R1234yf, R600a, R600, R290, R161, R32, and propylene is presented for air-conditioning application. Ejector has been modeled by considering experimental data based correlations of component efficiencies to take care of all irreversibilities. Ejector area ratio has been optimized based on maximum coefficient of performance (COP for typical air-conditioner operating temperatures. Selected refrigerants have been compared based on area ratio, pressure lift ratio, entrainment ratio, COP, COP improvement and volumetric cooling capacity. Effects of normal boiling point and critical point on the performances have been studied as well. Using ejector as an expansion device, maximum improvement in COP is noted in R1234yf (10.1%, which reduces the COP deviation with R134a (4.5% less in basic cycle and 2.5% less in ejector cycle. Hence, R1234yf seems to be best alternative for ejector expansion system due to its mild flammability and comparable volumetric capacity and cooling COP. refrigerant R161 is superior to R134a in terms of both COP and volumetric cooling capacity, although may be restricted for low capacity application due to its flammability.

Performance characteristics of low global warming potential R134a alternative refrigerants in ejector-expansion refrigeration system

Science.gov (United States)

Mishra, Shubham; Sarkar, Jahar

2016-12-01

Performance assessment of ejector-expansion vapor compression refrigeration system with eco-friendly R134a alternative refrigerants (R152a, R1234yf, R600a, R600, R290, R161, R32, and propylene) is presented for air-conditioning application. Ejector has been modeled by considering experimental data based correlations of component efficiencies to take care of all irreversibilities. Ejector area ratio has been optimized based on maximum coefficient of performance (COP) for typical air-conditioner operating temperatures. Selected refrigerants have been compared based on area ratio, pressure lift ratio, entrainment ratio, COP, COP improvement and volumetric cooling capacity. Effects of normal boiling point and critical point on the performances have been studied as well. Using ejector as an expansion device, maximum improvement in COP is noted in R1234yf (10.1%), which reduces the COP deviation with R134a (4.5% less in basic cycle and 2.5% less in ejector cycle). Hence, R1234yf seems to be best alternative for ejector expansion system due to its mild flammability and comparable volumetric capacity and cooling COP. refrigerant R161 is superior to R134a in terms of both COP and volumetric cooling capacity, although may be restricted for low capacity application due to its flammability.

Atmospheric observations for quantifying emissions of point-source synthetic greenhouse gases (CF4, NF3 and HFC-23)

Science.gov (United States)

Arnold, Tim; Manning, Alistair J.; Li, Shanlan; Kim, Jooil; Park, Sunyoung; Fraser, Paul J.; Mitrevski, Blagoj; Steele, L. Paul; Krummel, Paul B.; Mühle, Jens; Weiss, Ray F.

2016-04-01

The fluorinated species carbon tetrafluoride (CF4; PFC-14), nitrogen trifluoride (NF3) and trifluoromethane (CHF3; HFC-23) are potent greenhouse gases with 100-year global warming potentials of 6,630, 16,100 and 12,400, respectively. Unlike the majority of CFC-replacement compounds that are emitted from fugitive and mobile emission sources, these gases are largely emitted from large single point sources - semiconductor manufacturing facilities (all three), aluminium smelting plants (CF4) and chlorodifluoromethane factories (HFC-23). In this work we show the potential for atmospheric measurements to understand regional sources of these gases and to highlight emission 'hotspots'. We target our analysis on measurements from two Advanced Global Atmospheric Gases Experiment (AGAGE) long term monitoring sites that are particularly sensitive to regional emissions of these gases: Gosan on Jeju Island in the Republic of Korea and Cape Grim on Tasmania in Australia. These sites measure CF4, NF3 and HFC-23 alongside a suite of greenhouse and stratospheric ozone depleting gases every two hours using automated in situ gas-chromatography mass-spectrometry instrumentation. We couple each measurement to an analysis of air history using the regional atmospheric transport model NAME (Numerical Atmospheric dispersion Modelling Environment) driven by 3D meteorology from the Met Office's Unified Model, and use a Bayesian inverse method (InTEM - Inversion Technique for Emission Modelling) to calculate yearly emission changes over a decade (2005-2015) at high spatial resolution. At present these gases make a small contribution to global radiative forcing, however, given that their impact could rise significantly and that point sources of such gases can be mitigated, atmospheric monitoring could be an important tool for aiding emissions reduction policy.

40 CFR Appendix F to Subpart B of... - Standard for Recover-Only Equipment That Extracts a Single, Specific Refrigerant Other Than CFC...

Science.gov (United States)

2010-07-01

... does not recycle, any single, specific automotive refrigerant other than CFC-12 or HFC-134a, including... or equivalent new product specifications before reuse in a mobile air-conditioning system.” The... capable of ensuring removal of refrigerant from the system being serviced by reducing the system pressure...

Achievement report on development of global warming prevention related technologies in fiscal 1998. Development of HFC-23 destruction technology; 1998 nendo chikyu ondanka boshi kanren gijutsu kaihatsu seika hokokusho. HFC-23 hakai gijutsu no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-01-01

HFC-23 is produced as a by-product during HCFC-22 manufacturing (produced at by-production rate of about 2%, whereas the reaction control has limitation in reducing the production). This is one of the substances subjected to the greenhouse effect gas reduction in the climate change framework treaty. This paper describes the achievements in 1998 on developing the HFC-23 destruction technology. High-temperature pyrolysis decomposes the substance into HF and CO2, which are given absorption treatment by water and alkali to make them harmless, and are recovered finally as calcium fluoride. An equipment having the treatment capability of 195 kg/h was constructed. Design was made on a facility capable of treating fluorine containing waste water at 3 t/h at maximum. Utilities consumed in a factory (industrial water, acids for neutralization, and alkali) are used effectively to identify the effect of reducing the treatment cost. Discussions were given from the safety aspect on facilities to prevent leakage of fluorine containing waste water being a harmful substance. Fabrication was executed on a full-size treatment testing equipment that can utilize the utilities in the factory effectively, and trial equipment operation was performed to arrange the system prepared toward the future tests and researches. (NEDO)

Investigation of R-134a as a modeling fluid for supercritical water

International Nuclear Information System (INIS)

Jouvin, J.C.; Pioro, I.

2014-01-01

The objective of this paper is to investigate the feasibility of using Refrigerant-134a (R-134a) as a potential modeling fluid by comparing the thermophysical properties with those of water. Operating conditions of SuperCritical Water-cooled Reactors (SCWRs) are scaled into those of R-134a, in order to provide proper SCWR-equivalent conditions. The thermophysical properties for R-134a are obtained from NIST REFPROP software. The results indicate that the thermophysical properties of R-134a undergo significant changes within the critical and pseudocritical regions similar to that of supercritical water. An investigation into the pseudocritical region of R-134a was also conducted. (author)

The R-134a energy efficiency problem

International Nuclear Information System (INIS)

Behrens, N.; Dekleva, T.W.; Hartley, J.G.; Murphy, F.T.; Powell, R.L.

1990-01-01

This paper examines the controversy over the relative energy efficiencies of R-134a and R-12, from a theoretical thermodynamic perspective. In this regard, the authors have used an in-house process flowsheeting program which allows to simulate the complete thermodynamic cycle, and investigate the effects of superheat and subcooling. Special attention is given to the suitable basis for comparing the energy efficiencies of different refrigerants calculated from thermodynamic data. Modelling experiments demonstrate the relative extent to which R-12 and R-134a respond differently to superheat and subcooling. With appropriate superheat and subcooling taken into consideration, such as applied in standard practice in the home appliance industry, R-134a can provide COP values essentially equivalent to that of R-12

Final Project Closeout Report for Sprint Hydrogen Fuel Cell (HFC) Deployment Project in California, Gulf Coast and Eastern Seaboard Markets

Energy Technology Data Exchange (ETDEWEB)

Kenny, Kevin [Sprint, Reston, VA (United States); Bradley, Dwayne [Burns & McDonnell, Kansas City, MO (United States)

2015-09-01

Sprint is one of the telecommunications industry leaders in the deployment of hydrogen fuel cell (HFC) systems to provide backup power for their mission critical wireless network facilities. With several hundred fuel cells commissioned in California, states in the gulf coast region, and along the upper eastern seaboard. A strong incentive for advancing the integration of fuel cells into the Sprint network came through the award of a Department of Energy (DOE) grant focused on Market Transformation activities for project (EE0000486). This grant was funded by the 2009 American Recovery and Reinvestment Act (ARRA). The funding provided by DOE ($7.295M) was allocated to support the installation of 260 new HFC systems, equipped with an on-site refillable Medium Pressure Hydrogen Storage Solution (MPHSS), as well as for the conversion of 21 low pressure hydrogen systems to the MPHSS, in hopes of reducing barriers to market acceptance.

Examination of transient characteristics of two-phase natural circulation within a Freon-113 boiling/condensation loop

International Nuclear Information System (INIS)

Tanimoto, K.; Ishii, M.

1998-01-01

Transient characteristics of two-phase natural circulation within a Freon-113 loop with a large condenser have been examined mainly focused on the flashing phenomenon. General behavior was described and parametric studies were performed. The items observed were the period and duration of flashing, peak flow rate, amount of flow carryover per flashing, lowest-peak liquid level within the condenser, and the peak void distribution in the riser section. The parameters considered were the heater power input, valve friction at the heater inlet (simulating the loopwise friction), condenser cooling, degree of subcooling at the heater inlet, and the heat loss to the surroundings. As a whole, the heater power input, valve friction, and the rate of condenser cooling played important roles in flashing while the other effects being marginal. In general, the flow appeared to be more unstable with the larger condensing surface which causes the condensation-induced flashing. (orig.)

22 CFR 134.25 - Settlement.

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2010-04-01

... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Settlement. 134.25 Section 134.25 Foreign... Considering Applications § 134.25 Settlement. The applicant and the Department of State may agree on a proposed settlement of the award before final action on the application, either in connection with a...

6 CFR 13.4 - Investigation.

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2010-01-01

... 6 Domestic Security 1 2010-01-01 2010-01-01 false Investigation. 13.4 Section 13.4 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY PROGRAM FRAUD CIVIL REMEDIES § 13.4 Investigation. (a) If an Investigating Official concludes that a subpoena pursuant to the Authority conferred by...

13 CFR 134.213 - Discovery.

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2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Discovery. 134.213 Section 134.213... OFFICE OF HEARINGS AND APPEALS Rules of Practice for Most Cases § 134.213 Discovery. (a) Motion. A party may obtain discovery only upon motion, and for good cause shown. (b) Forms. The forms of discovery...

Stabilization study on a wet-granule tableting method for a compression-sensitive benzodiazepine receptor agonist.

Science.gov (United States)

Fujita, Megumi; Himi, Satoshi; Iwata, Motokazu

2010-03-01

SX-3228, 6-benzyl-3-(5-methoxy-1,3,4-oxadiazol-2-yl)-5,6,7,8-tetrahydro-1,6-naphthyridin-2(1H)-one, is a newly-synthesized benzodiazepine receptor agonist intended to be developed as a tablet preparation. This compound, however, becomes chemically unstable due to decreased crystallinity when it undergoes mechanical treatments such as grinding and compression. A wet-granule tableting method, where wet granules are compressed before being dried, was therefore investigated as it has the advantage of producing tablets of sufficient hardness at quite low compression pressures. The results of the stability testing showed that the drug substance was chemically considerably more stable in wet-granule compression tablets compared to conventional tablets. Furthermore, the drug substance was found to be relatively chemically stable in wet-granule compression tablets even when high compression pressure was used and the effect of this pressure was small. After investigating the reason for this excellent stability, it became evident that near-isotropic pressure was exerted on the crystals of the drug substance because almost all the empty spaces in the tablets were occupied with water during the wet-granule compression process. Decreases in crystallinity of the drug substance were thus small, making the drug substance chemically stable in the wet-granule compression tablets. We believe that this novel approach could be useful for many other compounds that are destabilized by mechanical treatments.

AN EXPERIMENTAL STUDY ON A VAPOR COMPRESSION REFRIGERATION CYCLE BY ADDING INTERNAL HEAT EXCHANGER

Directory of Open Access Journals (Sweden)

Muhammad Asmail Eleiwi

2013-05-01

Full Text Available Thispaper presents practical study to improve the indication COP of a vaporcompression refrigeration cycle in instrumented automobile air conditioner bydesigning internal heat exchanger and installing it in the vapor compressionrefrigeration cycle.  Two cases of  vapor compression refrigeration cycle were takenin this paper:  the first case is thatthe vapor compression refrigeration cycle without internal heat exchanger andin  the second case the vapor compressionrefrigeration cycle with heat exchanger ; in these two cases, the temperatureat each point of  a vapor compressionrefrigeration cycle, the low and the high pressure ,the indoor temperature andthe outdoor temperature were measured at each time at compressor speed 1450 rpmand 2900 rpm for each blower speed 1, blower speed 2 and blower speed 3.Therefrigerant fluid was used in the vapor compression refrigeration cycle withoutIHE and with IHE is R134a..

13 CFR 134.217 - Settlement.

Science.gov (United States)

2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Settlement. 134.217 Section 134... BEFORE THE OFFICE OF HEARINGS AND APPEALS Rules of Practice for Most Cases § 134.217 Settlement. At any... have settled the case, and may file with such motion a copy of the settlement agreement. If the Judge...

Abundance and sources of atmospheric halocarbons in the Eastern Mediterranean

Science.gov (United States)

Schoenenberger, Fabian; Henne, Stephan; Hill, Matthias; Vollmer, Martin K.; Kouvarakis, Giorgos; Mihalopoulos, Nikolaos; O'Doherty, Simon; Maione, Michela; Emmenegger, Lukas; Peter, Thomas; Reimann, Stefan

2018-03-01

A wide range of anthropogenic halocarbons is released to the atmosphere, contributing to stratospheric ozone depletion and global warming. Using measurements of atmospheric abundances for the estimation of halocarbon emissions on the global and regional scale has become an important top-down tool for emission validation in the recent past, but many populated and developing areas of the world are only poorly covered by the existing atmospheric halocarbon measurement network. Here we present 6 months of continuous halocarbon observations from Finokalia on the island of Crete in the Eastern Mediterranean. The gases measured are the hydrofluorocarbons (HFCs), HFC-134a (CH2FCF3), HFC-125 (CHF2CF3), HFC-152a (CH3CHF2) and HFC-143a (CH3CF3) and the hydrochlorofluorocarbons (HCFCs), HCFC-22 (CHClF2) and HCFC-142b (CH3CClF2). The Eastern Mediterranean is home to 250 million inhabitants, consisting of a number of developed and developing countries, for which different emission regulations exist under the Kyoto and Montreal protocols. Regional emissions of halocarbons were estimated with Lagrangian atmospheric transport simulations and a Bayesian inverse modeling system, using measurements at Finokalia in conjunction with those from Advanced Global Atmospheric Gases Experiment (AGAGE) sites at Mace Head (Ireland), Jungfraujoch (Switzerland) and Monte Cimone (Italy). Measured peak mole fractions at Finokalia showed generally smaller amplitudes for HFCs than at the European AGAGE sites except for periodic peaks of HFC-152a, indicating strong upwind sources. Higher peak mole fractions were observed for HCFCs, suggesting continued emissions from nearby developing regions such as Egypt and the Middle East. For 2013, the Eastern Mediterranean inverse emission estimates for the four analyzed HFCs and the two HCFCs were 13.9 (11.3-19.3) and 9.5 (6.8-15.1) Tg CO2eq yr-1, respectively. These emissions contributed 16.8 % (13.6-23.3 %) and 53.2 % (38.1-84.2 %) to the total inversion

Comparison of the Effect of New Spice Freon Extracts Towards Ground Spices and Antioxidants for Improving the Quality of Bulgarian-Type Dry-Cured Sausage

Directory of Open Access Journals (Sweden)

Balev Dessislav Kostadinov

2017-03-01

Full Text Available Ground spices are a source of hazards for dry-fermented meat products. Since dry-cured sausages are not subjected to heat treatment, there is a high risk of microbial cross-contamination and physical impurities. The aim of this study was to determine effects of the replacement of 3 g/kg of ground black pepper (Piper nigrum L., and cumin (Cuminum cyminum with their aliquots of new freon extracts, and compare them with the effect of 0.2 g/kg antioxidant addition (taxifolin extract from Siberian larch (Larix sibirica Ledeb, rosemary (Rosmarinus officinalis L. extract, and butylated hydroxytoluene on sensory properties, color stability, proximate composition, free amino nitrogen and pH of Bulgarian-type dry-cured „Sudjuk“ sausages. The replacement of natural ground spices with aliquots of their extracts improved sensory properties and stabilized the color characteristics of the final product during 30 days of storage at 0–4°C. The addition of 0.2 g/kg rosemary extract was as effective as the addition of freon extracts on the overall assessment to the 14th day of the experiment. It was determined that the addition of antioxidants or spice extracts had no significant effect on proximate composition, pH, and free amino nitrogen accumulation of the “Sudjuk”. The addition of 0.2 g/kg, taxifolin or rosemary extracts and butylated hydroxytoluene was not so efficient in improving the sensory properties and color stabilization in comparison to the new freon spice extracts. The examined spice extracts can be successfully used to improve the quality of “Sudjuk” sausages.

Construction of a Lyapunov functional for 1D-viscous compressible barotropic fluid equations admitting vacua

Czech Academy of Sciences Publication Activity Database

Penel, P.; Straškraba, Ivan

2010-01-01

Roč. 134, č. 3 (2010), s. 278-294 ISSN 0007-4497 R&D Projects: GA ČR GA201/08/0012 Institutional research plan: CEZ:AV0Z10190503 Keywords : compressible fluid * Navier-Stokes equations * asymptotic behavior Subject RIV: BA - General Mathematics Impact factor: 0.722, year: 2010 http://www.sciencedirect.com/science/article/pii/S0007449709000153

An investigation into the effects of a cosine axial heat flux distribution on burnout in a 12ft long annulus using Freon-12

International Nuclear Information System (INIS)

Stevens, G.F.; Wood, R.W.; Pryzbylski, J.

1968-09-01

Burnout results are given for an annular test section 12ft long and having an inner heated rod 0.625 in diameter, and an outer unheated tube of 0.825in bore. In one case the rod was uniformly heated and in the other case the rod was given a symmetrical chopped cosine heat flux profile. The Freon data is shown to compare well with equivalent water data using an established scaling technique; this applied both to burnout power and to burnout position. The comparison is made at pressures of 1000 psia and 750 psia water equivalent and the same scaling factors are shown to work at both pressures. (author)

13 CFR 134.402 - Appeal petition.

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2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Appeal petition. 134.402 Section 134.402 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION RULES OF PROCEDURE GOVERNING... § 134.402 Appeal petition. In addition to the requirements of § 134.203, an appeal petition must state...

13 CFR 134.310 - Discovery.

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2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Discovery. 134.310 Section 134.310 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION RULES OF PROCEDURE GOVERNING CASES BEFORE THE... Designations § 134.310 Discovery. Discovery will not be permitted in appeals from size determinations or NAICS...

19 CFR 134.34 - Certain repacked articles.

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2010-04-01

... 19 Customs Duties 1 2010-04-01 2010-04-01 false Certain repacked articles. 134.34 Section 134.34... TREASURY COUNTRY OF ORIGIN MARKING Exceptions to Marking Requirements § 134.34 Certain repacked articles. (a) Exception for repacked articles. An exception under § 134.32(d) may be authorized in the...

24 CFR 13.4 - Reports.

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2010-04-01

... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Reports. 13.4 Section 13.4 Housing... PENALTY MAIL IN THE LOCATION AND RECOVERY OF MISSING CHILDREN § 13.4 Reports. HUD shall compile and submit... report on its experience in implementing S. 1195 Official Mail Use in the Location and Recovery of...

13 CFR 134.203 - The petition.

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2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false The petition. 134.203 Section 134... BEFORE THE OFFICE OF HEARINGS AND APPEALS Rules of Practice for Most Cases § 134.203 The petition. (a) A petition must contain the following: (1) The basis of OHA's jurisdiction; (2) A copy of the SBA...

19 CFR 134.53 - Examination packages.

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2010-04-01

... 19 Customs Duties 1 2010-04-01 2010-04-01 false Examination packages. 134.53 Section 134.53... TREASURY COUNTRY OF ORIGIN MARKING Articles Found Not Legally Marked § 134.53 Examination packages. (a) Site of marking—(1) Customs custody. Articles (or containers) in examination packages may be marked by...

Hydrochlorofluorocarbon and hydrofluorocarbon emissions in East Asia determined by inverse modeling

Directory of Open Access Journals (Sweden)

A. Stohl

2010-04-01

Full Text Available The emissions of three hydrochlorofluorocarbons, HCFC-22 (CHClF₂, HCFC-141b (CH₃CCl₂F and HCFC-142b (CH₃CClF₂ and three hydrofluorocarbons, HFC-23 (CHF₃, HFC-134a (CH₂FCF₃ and HFC-152a (CH₃CHF₂ from four East Asian countries and the Taiwan region for the year 2008 are determined by inverse modeling. The inverse modeling is based on in-situ measurements of these halocarbons at the Japanese stations Cape Ochi-ishi and Hateruma, the Chinese station Shangdianzi and the South Korean station Gosan. For every station and every 3 h, 20-day backward calculations were made with the Lagrangian particle dispersion model FLEXPART. The model output, the measurement data, bottom-up emission information and corresponding uncertainties were fed into an inversion algorithm to determine the regional emission fluxes. The model captures the observed variation of halocarbon mixing ratios very well for the two Japanese stations but has difficulties explaining the large observed variability at Shangdianzi, which is partly caused by small-scale transport from Beijing that is not adequately captured by the model. Based on HFC-23 measurements, the inversion algorithm could successfully identify the locations of factories known to produce HCFC-22 and emit HFC-23 as an unintentional byproduct. This lends substantial credibility to the inversion method. We report national emissions for China, North Korea, South Korea and Japan, as well as emissions for the Taiwan region. Halocarbon emissions in China are much larger than the emissions in the other countries together and contribute a substantial fraction to the global emissions. Our estimates of Chinese emissions for the year 2008 are 65.3±6.6 kt/yr for HCFC-22 (17% of global emissions extrapolated from Montzka et al., 2009, 12.1±1.6 kt/yr for HCFC-141b (22%, 7.3±0.7 kt/yr for HCFC-142b (17%, 6.2±0.7 kt/yr for HFC

Kinetic and spectroscopic characterization of the E134A- and E134D-altered dapE-encoded N-succinyl-L,L-diaminopimelic acid desuccinylase from Haemophilus influenzae.

Science.gov (United States)

Davis, Ryan; Bienvenue, David; Swierczek, Sabina I; Gilner, Danuta M; Rajagopal, Lakshman; Bennett, Brian; Holz, Richard C

2006-03-01

Glutamate-134 (E134) is proposed to act as the general acid/base during the hydrolysis reaction catalyzed by the dapE-encoded N-succinyl-L,L-diaminopimelic acid desuccinylase (DapE) from Haemophilus influenzae. To date, no direct evidence has been reported for the role of E134 during catalytic turnover by DapE. In order to elucidate the catalytic role of E134, altered DapE enzymes were prepared in which E134 was substituted with an alanine and an aspartate residue. The Michaelis constant (K (m)) does not change upon substitution with aspartate but the rate of the reaction changes drastically in the following order: glutamate (100% activity), aspartate (0.09%), and alanine (0%). Examination of the pH dependence of the kinetic constants k (cat) and K (m) for E134D-DapE revealed ionizations at pH 6.4, 7.4, and approximately 9.7. Isothermal titration calorimetry experiments revealed a significant weakening in metal K (d) values of E134D-DapE. D134 and A134 perturb the second divalent metal binding site significantly more than the first, but both altered enzymes can still bind two divalent metal ions. Structural perturbations of the dinuclear active site of DapE were also examined for two E134-substituted forms, namely E134D-DapE and E134A-DapE, by UV-vis and electron paramagnetic resonance (EPR) spectroscopy. UV-vis spectroscopy of Co(II)-substituted E134D-DapE and E134A-DapE did not reveal any significant changes in the electronic absorption spectra, suggesting that both Co(II) ions in E134D-DapE and E134A-DapE reside in distorted trigonal bipyramidal coordination geometries. EPR spectra of [Co_(E134D-DapE)] and [Co_(E1341A-DapE] are similar to those observed for [CoCo(DapE)] and somewhat similar to the spectrum of [Co(H(2)O)(6)](2+) which typically exhibit E/D values of approximately 0.1. Computer simulation returned an axial g-tensor with g ((x,y))=2.24 and E/D=0.07; g ( z ) was only poorly determined, but was estimated as 2.5-2.6. Upon the addition of a second Co

Abundance and sources of atmospheric halocarbons in the Eastern Mediterranean

Directory of Open Access Journals (Sweden)

F. Schoenenberger

2018-03-01

Full Text Available A wide range of anthropogenic halocarbons is released to the atmosphere, contributing to stratospheric ozone depletion and global warming. Using measurements of atmospheric abundances for the estimation of halocarbon emissions on the global and regional scale has become an important top-down tool for emission validation in the recent past, but many populated and developing areas of the world are only poorly covered by the existing atmospheric halocarbon measurement network. Here we present 6 months of continuous halocarbon observations from Finokalia on the island of Crete in the Eastern Mediterranean. The gases measured are the hydrofluorocarbons (HFCs, HFC-134a (CH2FCF3, HFC-125 (CHF2CF3, HFC-152a (CH3CHF2 and HFC-143a (CH3CF3 and the hydrochlorofluorocarbons (HCFCs, HCFC-22 (CHClF2 and HCFC-142b (CH3CClF2. The Eastern Mediterranean is home to 250 million inhabitants, consisting of a number of developed and developing countries, for which different emission regulations exist under the Kyoto and Montreal protocols. Regional emissions of halocarbons were estimated with Lagrangian atmospheric transport simulations and a Bayesian inverse modeling system, using measurements at Finokalia in conjunction with those from Advanced Global Atmospheric Gases Experiment (AGAGE sites at Mace Head (Ireland, Jungfraujoch (Switzerland and Monte Cimone (Italy. Measured peak mole fractions at Finokalia showed generally smaller amplitudes for HFCs than at the European AGAGE sites except for periodic peaks of HFC-152a, indicating strong upwind sources. Higher peak mole fractions were observed for HCFCs, suggesting continued emissions from nearby developing regions such as Egypt and the Middle East. For 2013, the Eastern Mediterranean inverse emission estimates for the four analyzed HFCs and the two HCFCs were 13.9 (11.3–19.3 and 9.5 (6.8–15.1 Tg CO2eq yr−1, respectively. These emissions contributed 16.8 % (13.6–23.3 % and 53.2 % (38.1–84.2�

miR-134: A Human Cancer Suppressor?

Directory of Open Access Journals (Sweden)

Jing-Yu Pan

2017-03-01

Full Text Available MicroRNAs (miRNAs are small noncoding RNAs approximately 20–25 nt in length, which play crucial roles through directly binding to corresponding 3′ UTR of targeted mRNAs. It has been reported that miRNAs are involved in numerous of diseases, including cancers. Recently, miR-134 has been identified to dysregulate in handles of human cancers, such as lung cancer, glioma, breast cancer, colorectal cancer, and so on. Increasing evidence indicates that miR-134 is essential for human carcinoma and participates in tumor cell proliferation, apoptosis, invasion and metastasis, drug resistance, as well as cancer diagnosis, treatment, and prognosis. Nevertheless, its roles in human cancer are still ambiguous, and its mechanisms are sophisticated as well, referring to a variety of targets and signal pathways, such as STAT5B, KRAS, MAPK/ERK signal pathway, Notch pathway, etc. Herein, we review the crucial roles of miR-134 in scores of human cancers via analyzing latest investigations, which might provide evidence for cancer diagnose, treatment, prognosis, or further investigations.

Experimental Performance Investigation of New Low-GWP Refrigerants for Use in Two-Phase Evaporative Cooling of Electronics

OpenAIRE

Nicolette-Baker, Alexis; Garr, Elizabeth; Sathe, Abhijit; O'Shaughnessey, Steve

2014-01-01

With growing global warning concerns on the current breed of HFC refrigerants, a search for more environmentally-friendly fluids has already begun. Potential alternatives to replace R134a should have significantly lower global warming potential (GWP), operate at similar system pressures, and maintain all other advantages of R134a (non-flammability, dielectric properties, etc.). This study investigates four possible alternatives that have been identified by AHRI in its Low-GWP Alternative Refr...

Emissions of halocarbons from mobile vehicle air conditioning system in Hong Kong

Energy Technology Data Exchange (ETDEWEB)

Yan, H.H.; Guo, H., E-mail: ceguohai@polyu.edu.hk; Ou, J.M.

2014-08-15

Highlights: • Halocarbon emissions from MVACS were characterized using bottom up approach. • Quantification of emission inventory was revealed using AUV Tools. • Potential emission reduction was estimated under 3 possible mitigation scenarios. • The results are useful for the policy makers to formulate and implement future phase-out schedule. - Abstract: During the implementation of Montreal Protocol, emission inventories of halocarbons in different sectors at regional scale are fundamental to the formulation of relevant management strategy and inspection of the implementation efficiency. This study investigated the emission profile of halocarbons used in the mobile vehicle air conditioning system, the leading sector of refrigeration industry in terms of the refrigerant bank, market and emission, in the Hong Kong Special Administrative Region, using a bottom-up approach developed by 2006 IPCC Good Practice Guidance. The results showed that emissions of CFC-12 peaked at 53 tons ODP (Ozone Depletion Potential) in 1992 and then gradually diminished, whereas HFC-134a presented an increasing emission trend since 1990s and the emissions of HFC-134a reached 65,000 tons CO{sub 2}-equivelant (CO{sub 2}-eq) by the end of 2011. Uncertainty analysis revealed relatively high levels of uncertainties for special-purpose vehicles and government vehicles. Moreover, greenhouse gas (GHG) abatements under different scenarios indicated that potential emission reduction of HFC-134a ranged from 4.1 to 8.4 × 10{sup 5} tons CO{sub 2}-eq. The findings in this study advance our knowledge of halocarbon emissions from mobile vehicle air conditioning system in Hong Kong.

Emissions of halocarbons from mobile vehicle air conditioning system in Hong Kong

International Nuclear Information System (INIS)

Yan, H.H.; Guo, H.; Ou, J.M.

2014-01-01

Highlights: • Halocarbon emissions from MVACS were characterized using bottom up approach. • Quantification of emission inventory was revealed using AUV Tools. • Potential emission reduction was estimated under 3 possible mitigation scenarios. • The results are useful for the policy makers to formulate and implement future phase-out schedule. - Abstract: During the implementation of Montreal Protocol, emission inventories of halocarbons in different sectors at regional scale are fundamental to the formulation of relevant management strategy and inspection of the implementation efficiency. This study investigated the emission profile of halocarbons used in the mobile vehicle air conditioning system, the leading sector of refrigeration industry in terms of the refrigerant bank, market and emission, in the Hong Kong Special Administrative Region, using a bottom-up approach developed by 2006 IPCC Good Practice Guidance. The results showed that emissions of CFC-12 peaked at 53 tons ODP (Ozone Depletion Potential) in 1992 and then gradually diminished, whereas HFC-134a presented an increasing emission trend since 1990s and the emissions of HFC-134a reached 65,000 tons CO 2 -equivelant (CO 2 -eq) by the end of 2011. Uncertainty analysis revealed relatively high levels of uncertainties for special-purpose vehicles and government vehicles. Moreover, greenhouse gas (GHG) abatements under different scenarios indicated that potential emission reduction of HFC-134a ranged from 4.1 to 8.4 × 10 5 tons CO 2 -eq. The findings in this study advance our knowledge of halocarbon emissions from mobile vehicle air conditioning system in Hong Kong

Behaviour of 134Cs in the aquatic ecosystems

International Nuclear Information System (INIS)

Xu Yinliang; Chen Chuanqun

1992-07-01

The diminution of 134 Cs in the aquatic phases and the absorption of 134 Cs by aquatic lives observe the exponential expression. i.e. Y Ae be . The relationships between the enrichment factor of 134 Cs(K) and the time(t) in the aquatic lives can be represented by a linear equation, K A + Bt. The value of K in the Alternanthera philoxeroides was about 560. That can be used for monitoring and purifying the water phase contaminated by 134 Cs. Fish can absorb 134 Cs from water phase and store it in liver and kidney. The specific activity of 134 Cs in fish flesh was low but the percentage of radioactivity was high that was about 30% of total radioactivity in the fish. River mud can strongly absorb 134 Cs and reduce the absorption by aquatic lives. It is a good adsorbent and purifying agent with low cost for treatment of 134 Cs. The K + can prevent aquatic lives from absorbing Cs + because of antagonistic function

Dicty_cDB: CHI134 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available CH (Link to library) CHI134 (Link to dictyBase) - - - Contig-U11723-1 CHI134P (Link... to Original site) CHI134F 581 CHI134Z 736 CHI134P 1297 - - Show CHI134 Library CH (Link to library) Clone ID CHI134 (Link to dict...yBase) Atlas ID - NBRP ID - dictyBase ID - Link to Contig Contig-U11723-1 Original site URL http://dict...gl*kta*g*IIMESNKSSSHGDVSTSPSFLNNHHQFNNGGDIIPKKKKNRIMHVG SYEVGKTLGNGTFGKVKLGTNICTK...PVIEAPKTRRMSLDSR MLNGDQQSLVEKNQHMASPRTSKGIFKXSTTTTKSPEKTIIELKRSLEESGLFTKKKGPY LXLCFDEDNSVKFQIEIVKICNLDLTGIQLKRLSGDTWKYKDICT

Behavior of cesium-134 in the tea tree

International Nuclear Information System (INIS)

Xu Yinliang; Chen Kaixuan; Chen Chuangqun

1996-01-01

The radioactivity changes of 134 Cs in the aged and the young leaves followed an exponential regression function after spraying 134 Cs in the tea trees. Contamination by spraying 134 Cs greatly harmed tea tree and by irrigating or mixing 134 Cs with soil resulted in a potential endangerment. The concentrating ability of tea leaves for 134 CS was very low and K value was 0.02. After the fresh tea leaves were processed to dry tea, the content of 134 Cs decreased by about 13.3%. When the tea leaves were soaked in hot water, the extraction ratio was around 83.6%

13 CFR 134.409 - Decision on appeal.

Science.gov (United States)

2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Decision on appeal. 134.409 Section 134.409 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION RULES OF PROCEDURE GOVERNING... § 134.409 Decision on appeal. (a) A decision of the Administrative Law Judge under this subpart is the...

Ultimate refrigerating conditions, behavior turning and a thermodynamic analysis for absorption–compression hybrid refrigeration cycle

International Nuclear Information System (INIS)

Zheng Danxing; Meng Xuelin

2012-01-01

Highlights: ► Two novel fundamental concepts of the absorption refrigeration cycle were proposed. ► The interaction mechanism of compressor pressure increasing with other key-parameters was investigated. ► A set of optimal operating condition of hybrid refrigeration cycle was found. ► A simulation and investigation for R134a-DMF hybrid refrigeration cycle was performed. - Abstract: The absorption–compression hybrid refrigeration cycle has been considered as an effective approach to reduce the mechanical work consumption by using low-grade heat, such as solar energy. This work aims at studying the thermodynamic mechanism of the hybrid refrigeration cycle. Two fundamental concepts have been proposed, which are the ultimate refrigerating temperature (or the ultimate temperature lift) and the behavior turning. On the basis of that, the interaction mechanism of compressor pressure increasing with other key-parameters and the impact of compressor pressure increasing on the cycle performance have been investigated. The key-parameters include the concentration difference, the circulation ratio of working fluid, etc. The work points out that the hybrid refrigeration cycle performance varies with the change of compressor outlet pressure and depends on which one achieves dominance in the hybrid refrigeration cycle, the absorption sub-system or the compression sub-system. The behavior turning point during parameters changing corresponds to a maximum value of the heat powered coefficient of performance. In this case, the hybrid refrigeration cycle performance is optimal because the low-grade heat utilization is the most effective. In addition, to validate the theoretical analysis, a solar hybrid refrigeration cycle with R134a–DMF as working pair was simulated. The Peng–Robinson equation of state was adopted to calculate thermophysical properties when the reliability assessment of the prediction models on the available literature data of R134a–DMF system had been

Composition shift in liquid-recirculation refrigerating systems: an experimental investigation for the pure fluid R134a and the mixture R32/134a

Energy Technology Data Exchange (ETDEWEB)

Giuliani, G.; Marchesi Donati, F.; Polonara, F. [Ancona Univ. (Italy). Dip. di Energetica; Hewitt, N.J. [University of Ulster at Coleraine, Northern Ireland (United Kingdom). NICERT

1999-09-01

The ability of zeotropic mixtures with a remarkable temperature glide to operate in liquid-recirculation systems is investigated and the results of an experimental comparison between the performances of the pure fluid R134a and the zeotropic mixture R32/134a (25/75% by mass) are presented. R134a performs slightly better in the liquid-recirculation mode than in the traditional dry-expansion mode; on the other hand, liquid-recirculation configuration has a detrimental effect on the zeotropic mixture's performance. The reason for this detrimental effect is the mixture component separation which occurs at the liquid/vapor separator. The effect of this separation is investigated using gas chromatograph analysis.

19 CFR 134.14 - Articles usually combined.

Science.gov (United States)

2010-04-01

... 19 Customs Duties 1 2010-04-01 2010-04-01 false Articles usually combined. 134.14 Section 134.14... TREASURY COUNTRY OF ORIGIN MARKING Articles Subject to Marking § 134.14 Articles usually combined. (a) Articles combined before delivery to purchaser. When an imported article is of a kind which is usually...

Pitot survey of exhaust flow field of a 2-D scramjet nozzle at Mach 6 with air or freon and argon used for exhaust simulation

Science.gov (United States)

Monta, William J.

1992-01-01

A pitot-rake survey of the simulated exhaust of a half-span scramjet nozzle model was conducted in the Langley 20-Inch Mach 6 Tunnel to provide an additional data set for computational fluid dynamics (CFD) code comparisons. A wind-tunnel model was tested with a 26-tube pitot rake that could be manually positioned along the mid-semispan plane of the model. The model configuration had an external expansion surface of 20 degrees and an internal cowl expansion of 12 degrees; tests were also performed with a flow fence. Tests were conducted at a free-stream Reynolds number of approximately 6.5 x 10(exp 6) per foot and a model angle of attack of -0.75 degrees. The two exhaust gas mediums that were tested were air and a Freon 12-argon mixture. Each medium was tested at two jet total pressures at approximately 28 and 14 psia. This document presents the flow-field survey results in graphical as well as tabular form, and several observations concerning the results are discussed. The surveys reveal the major expected flow-field characteristics for each test configuration. For a 50-percent freon 12 and 50-percent argon mixture by volume (Fr-Ar), the exhaust jet pressures were slightly higher than those for air. The addition of a flow fence slightly raised the pitot pressure for the Fr-Ar mixture, but it produced little change for air. For the Fr-Ar exhaust, the plume was larger and the region between the shock wave and plume was smaller.

13 CFR 134.715 - Can a Judge reconsider his decision?

Science.gov (United States)

2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Can a Judge reconsider his decision? 134.715 Section 134.715 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION RULES OF....715 Can a Judge reconsider his decision? (a) The Judge may reconsider an appeal decision within 20...

12 CFR 13.4 - Recommendations to customers.

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Recommendations to customers. 13.4 Section 13.4... PRACTICES § 13.4 Recommendations to customers. In recommending to a customer the purchase, sale or exchange... reasonable grounds for believing that the recommendation is suitable for the customer upon the basis of the...

Calculated trends and the atmospheric abundance of 1,1,1,2-tetrafluoroethane, 1,1-dichloro-1-fluoroethane, and 1-chloro-1,1-difluoroethane using automated in-situ gas chromatography-mass spectrometry measurements recorded at Mace Head, Ireland, from October 1994 to March 1997

Science.gov (United States)

Simmonds, P. G.; O'Doherty, S.; Huang, J.; Prinn, R.; Derwent, R. G.; Ryall, D.; Nickless, G.; Cunnold, D.

1998-01-01

The first in-situ measurements by automated gas chromatograph-mass spectrometer are reported for 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1-dichloro-1-fluoroethane, (HCFC-141b), and 1-chloro-1,1-difluoroethane, (HCFC-142b). These compounds are steadily replacing the chlorofluorocarbons (CFCs) as refrigerants, foam-blowing agents, and solvents. The concentrations of all three compounds are shown to be rapidly increasing in the atmosphere, with 134a increasing at a rate of 2.05±0.02 ppt yr-1 over the 30 months of observations. Similarly, 141b and 142b increased at rates of 2.49±0.03 and 1.24±0.02 ppt yr-1, respectively, over the same period. The concentrations recorded at the atmospheric research station at Mace Head, Ireland, on January 1, 1996, the midpoint of the time series, were 3.67 ppt (134a), 7.38 ppt (141b), and 8.78 ppt (142b). From these observations we optimally estimate the HCFC and HFC emissions using a 12-box global model and OH concentrations derived from global 1,1,1-trichloroethane (CCl3CH3) measurements. Comparing two methods of estimating emissions with independent industry estimates shows satisfactory agreement for 134a and 141b, while for 142b, industry estimates are less than half those required to explain our observations.

The NCSU [North Carolina State Univ.] freon PWR [pressurized water reactor] loop

International Nuclear Information System (INIS)

Caves, J.R.; Doster, J.M.; Miller, G.D.; Wehring, B.W.; Turinsky, P.J.

1989-01-01

The nuclear engineering department at North Carolina State University has designed and constructed an operating scale model of a pressurized water reactor (PWR) nuclear steam supply system (NSSS). This facility will be used for education, training, and research. The loop uses electric heaters to simulate the reactor core and Freon as the primary and secondary coolant. Viewing ports at various locations in the loop allow the students to visualize flow regimes in normal and off-normal operating conditions. The objective of the design effort was to scale the thermal-hydraulic characteristics of a two-loop Westinghouse NSSS. Provisions have been made for the simulation of various abnormal occurrences. The model is instrumented in much the same manner as the actual NSSS. Current research projects using the loop include the development of adaptive expert systems to monitor the performance of the facility, diagnose mechanical faults, and to make recommendations to operators for mitigation of accidents. This involves having thermal-hydraulics and core-physics simulators running faster than real time on a mini-supercomputer, with operating parameters updated by communication with the data acquisition and control computer. Further opportunities for research will be investigated as they arise

Effects of synthetic oil in a compression refrigeration system using R410A. Part II: quality of heat transfer and pressure losses within the heat exchangers

Energy Technology Data Exchange (ETDEWEB)

Lottin, O.; Guillemet, P. [Ecole Polytechnique de l' Universite de Nantes (France). Laboratoire de Thermocinetique; Lebreton, J-M. [Electricite de France, Moret sur Loing (France)

2003-11-01

The consequences of the oil rejected by the compressor of a vapour-compression refrigeration system on the operation of the evaporator and condenser are analysed. The modelled prototype uses the mixture of HFC R410A and a synthetic polyolester (POE) oil. The rise of the amount of lubricant circulating in the system leads to a progressive change in the behaviour of the mixture of refrigerant and oil that, for the higher oil mass fraction, evolves like a zeotropic mixture. One also observes that the presence of lubricant is generally associated with a fall of the performances of the heat exchangers, except however in the evaporator where an optimum is observed when the quantity of oil is equal to 0.1% of the total mass of the mixture. Some conclusions are drawn about the choice of correlations for the calculation of the refrigerant side heat transfer coefficient in a plate evaporator. (author)

Journal of Earth System Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

An integrated assessment of emissions of some important refrigerant ozone depleting substances (ODSs) (CFC-11, CFC-12, HCFC-141b and HFC-134a) and their contributed ozone depletion potentials (ODPs) and global warming potentials (GWPs) have been made in the megacity Lahore (Pakistan) for the periodfrom ...

FY 1999 survey report on the survey to grasp new technologies for destruction of freons, etc. in Japan; 1999 nendo Nippon no atarashii freon nado hakai gijutsu no haaku chosa hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

At the end of 1995, a total abolition of the production of the specified freons (CFC) was achieved. In future, it will be important to proceed with the appropriate recovery/destruction of the CFC, etc. which has been used so far, not only for the protection of ozone layer, but for the prevention of global warming. For the international study of facilities (technology) for destruction CFC, etc., the Technical Assessment Committee (TAC) was installed for destruction technology of ozone layer depletion substances (ODS) under the United Nations Environment Programme (UNEP), and the destruction efficiency (DE) of ODS was set up. In Japan, more than 30 facilities are already handling the destruction of CFC on a commercial basis. The number is expected to increase by the promotion of protection of ozone layer and prevention of global warming. This survey indicated quantitatively and qualitatively based on the TAC DE what the facilities for destruction of CFC should be which were considered of domestic laws in Japan, and was made a guide for existing facilities and ones to be newly installed. (NEDO)

Potential energy and dipole moment surfaces for HF@C60: Prediction of spectral and electric response properties

Science.gov (United States)

Kalugina, Yulia N.; Roy, Pierre-Nicholas

2017-12-01

We present a five-dimensional potential energy surface (PES) for the HF@C60 system computed at the DF-LMP2/cc-pVTZ level of theory. We also calculated a five-dimensional dipole moment surface (DMS) based on DFT(PBE0)/cc-pVTZ calculations. The HF and C60 molecules are considered rigid with bond length rHF = 0.9255 Å (gas phase ground rovibrational state geometry). The C60 geometry is of Ih symmetry. The ab initio points were fitted to obtain a PES in terms of bipolar spherical harmonics. The minimum of the PES corresponds to a geometry where the center of mass of HF is located 0.11 Å away from the center of the cage with an interaction energy of -6.929 kcal/mol. The DMS was also represented in terms of bipolar spherical harmonics. The PES was used to calculate the rotation-translation bound states of HF@C60, and good agreement was found relative to the available experimental data [A. Krachmalnicoff et al., Nat. Chem. 8, 953 (2016)] except for the splitting of the first rotational excitation levels. We propose an empirical adjustment to the PES in order to account for the experimentally observed symmetry breaking. The form of that effective PES is additive. We also propose an effective Hamiltonian with an adjusted rotational constant in order to quantitatively reproduce the experimental results including the splitting of the first rotational state. We use our models to compute the molecular volume polarizability of HF confined by C60 and obtain good agreement with experiment.

29 CFR 2570.134 - Consequences of default.

Science.gov (United States)

2010-07-01

... 29 Labor 9 2010-07-01 2010-07-01 false Consequences of default. 2570.134 Section 2570.134 Labor Regulations Relating to Labor (Continued) EMPLOYEE BENEFITS SECURITY ADMINISTRATION, DEPARTMENT OF LABOR... ERISA Section 502(c)(7) § 2570.134 Consequences of default. For 502(c)(7) civil penalty proceedings...

49 CFR 195.134 - CPM leak detection.

Science.gov (United States)

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false CPM leak detection. 195.134 Section 195.134... PIPELINE Design Requirements § 195.134 CPM leak detection. This section applies to each hazardous liquid... computational pipeline monitoring (CPM) leak detection system and each replaced component of an existing CPM...

Uptake and disposition of 1,1-difluoroethane (HFC-152a) in humans.

Science.gov (United States)

Ernstgård, Lena; Sjögren, Bengt; Dekant, Wolfgang; Schmidt, Tobias; Johanson, Gunnar

2012-02-25

The aim of this study was to determine the toxicokinetics of inhaled 1,1-difluoroethane (HFC-152a) in humans. Healthy volunteers were exposed to 0, 200 or 1000 ppm 1,1-difluoroethane for 2h at light exercise in an exposure chamber. Capillary blood, urine and exhaled air were sampled up to 22 h post-exposure and analyzed for 1,1-difluoroethane. Fluoride and other potential metabolites were analyzed in urine. Symptoms of irritation and central nervous system effects were rated and inflammatory markers were analyzed in blood. Within a few minutes of exposure to 200 and 1000 ppm, 1,1-difluoroethane increased rapidly in blood and reached average levels of 7.4 and 34.3 μM, respectively. The post-exposure decreases in blood were fast and parallel to those in exhaled air. The observed time courses in blood and breath agreed well with those obtained with the PBPK model. The PBPK simulations indicate a net uptake during exposure to 1000 ppm of 6.6 mmol (6.7%) which corresponds to the amount exhaled post-exposure. About 20 μmol excess fluoride (0.013% of inhaled 1,1-difluoroethane on a molar basis) was excreted in urine after exposure to 1000 ppm, compared to control. No fluorine-containing metabolites were detected in urine. Symptom ratings and changes in inflammatory markers revealed no exposure-related effects. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Recycling of tailings from Korea Molybdenum Corporation as admixture for high-fluidity concrete.

Science.gov (United States)

Jung, Moon Young; Choi, Yun Wang; Jeong, Jae Gwon

2011-01-01

The main objective of this study is to develop an eco-friendly and a large recycling technique of flotation Tailings from korea (TK) from metal mines as construction materials such as admixtures for high-fluidity concrete (HFC). TK used in this study was obtained from the Korea Molybdenum Corporation in operation. TK was used as the alternative material to adjust flowability and viscosity of HFC in the form of powder agent which enables adjustment of concrete compressive strength. In this study, we have performed concrete rheological tests and concrete flowability tests to obtain the quality characteristics of TK for using as the admixture in producing HFC. The results indicated that the adequate mix ratio of cement to TK should be 8:2 (vol%). It is more effective to use the TK as admixture to control flowability, viscosity and strength of HFC than the normal concrete. It was found that TK could be recycled construction materials in bulk such as admixture for HFC, in terms of the economic and eco-friendly aspects.

Effect of the structured packing height on efficiency of freons mixture separation in a large-scale model of distillation column

Directory of Open Access Journals (Sweden)

Pavlenko Aleksandr

2017-01-01

Full Text Available Results of experimental studies of heat-and-mass transfer and hydrodynamic processes at distillation on a regular packing are presented. The mixture of freons R114–R21 at the pressure of 0.3 MPa was used as a working mixture. The mixture was separated on the Mellapak 350Y structured packing with the diameter of 0.9 m under the conditions of complete reflux (L/V = 1 at different packing heights. A specially designed liquid distributor with a possibility to change the density and pattern of drip points was used to irrigate the packing. The experimental data on the efficiency of mixture separation (height of transfer unit HTU and distribution of the local flow rate density over the column cross-section were compared. It is shown that an increase in the height of the structured packing from 2.1 m to 4.0 m leads to a significant decrease in the efficiency of mixture separation in the distillation column.

13 CFR 134.709 - When will a Judge dismiss an appeal?

Science.gov (United States)

2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false When will a Judge dismiss an appeal? 134.709 Section 134.709 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION RULES OF PROCEDURE GOVERNING CASES BEFORE THE OFFICE OF HEARINGS AND APPEALS Rules of Practice for Appeals From Women...

The 134Cs uptake by sunflower (Helianthus anuus, Less) cultivated on soil contaminated with 134Cs

International Nuclear Information System (INIS)

Poppy Intan Tjahaja; Putu Sukmabuana

2008-01-01

One of the methods for remediation of contaminated environment is phytoremediation techniques, i.e. the environmental remediation using plants. In this research the bioavailability of sunflower plant (Helianthus anuus, Less) in radiocaesium uptake from soil was studied for being considered as a phytoremediator later. Sunflower plants were cultivated on soil contaminated with 134 Cs with the concentrations of 29,3 kBq/kg ; 117,2 kBq/kg ; 557 kBq/kg for 45 days. As control the sunflowers were also cultivated on non contaminated soil. Observation was carried out every 5 days by sampling 3 plants and soils. The plant and soil samples were dried using infra red lamp for 24 hours, and then counted using gamma spectrometer. The counting results i.e. 134 Cs concentration on soil and plant parts were then analyzed to obtain transfer factor (TF) values. The highest TF values was reached on 26 th day, i.e. 0,87; 1,89 ; 2,82 for initial soil 134 Cs concentrations of 29,3 Bq/g ; 117,2 Bq/g ; 557 Bq/g, respectively. The TF values obtained expressed the capability of plants to accumulate 134 Cs from soils. The observation to the plants growth showed that the plants grew normally on the 134 Cs contaminated soil until the concentration of 557 Bq/g. The sunflower can be considered to be phytoremediator of andosol soil contaminated with Cs radionuclides. (author)

Oxidation behavior of TiC, ZrC, and HfC dispersed in oxide matrices

International Nuclear Information System (INIS)

Arun, R.; Subramanian, M.; Mehrotra, G.M.

1990-01-01

The oxidation behavior of hot pressed TiC-Al 2 O 3 , TiC-ZrO 2 , ZrC-ZrO 2 , and HfC-HfO 2 composites has been investigated at 1273 K. The oxidation of TiC, ZrC, and HfC in hot-pressed composites containing ZrO 2 and HfO 2 has been found to be extremely rapid. The kinetics of oxidation of TiC and a 90 wt% TiC-Al 2 O 3 composite appear to be faster compared to that of pure TiC. X-ray diffraction results for hot-pressed ZrC-HfO 2 and HfC-HfO 2 composites indicate partial stabilization of tetragonal ZrO 2 and HfO 2 phases in these composites

Construction of 1,3,4-Oxadiazole and 1,3,4-Thiadiazole Library with a High Level of Skeletal Diversity Based on Branching Diversity-Oriented Synthesis on Solid-Phase Supports.

Science.gov (United States)

Ha, Ji-Eun; Yang, Seung-Ju; Gong, Young-Dae

2018-02-12

An efficient solid-phase synthetic route for the construction of 1,3,4-oxadiazole and 1,3,4-thiadiazole libraries based on branching diversity-oriented synthesis (DOS) has been developed in this study. The core skeleton resins, 1,3,4-oxadiazole and 1,3,4-thiadiazole, were obtained through desulfurative and dehydrative cyclizations of thiosemicarbazide resin, respectively. Various functional groups have been introduced to the core skeleton resins, such as aryl, amine, amide, urea, thiourea, and an amino acid. Most of the libraries were purified by simple trituration without extraction or column chromatography after cleavage of the products from the solid-supported resin. As a result, we obtained high yields of pure 1,3,4-oxadiazole and 1,3,4-thiadiazole derivatives (total numbers = 128). Finally, we confirmed the drug-like properties of our library by calculation of physicochemical properties, displays of the skeletal diversities of the library in 3D-space, and occupation of a broad range of areas by their functional groups.

Heat-pump cool storage in a clathrate of freon

Science.gov (United States)

Tomlinson, J. J.

Presented are the analytical description and assessment of a unique heat pump/storage system in which the conventional evaporator of the vapor compression cycle is replaced by a highly efficient direct contract crystallizer. The thermal storage technique requires the formation of a refrigerant gas hydrate (a clathrate) and exploits an enthalpy of reaction comparable to the heat of fusion of ice. Additional system operational benefits include cool storage at the favorable temperatures of 4 to 7 C (40 to 45 F), and highly efficient heat transfer ates afforded by he direct contact mechanism. In addition, the experimental approach underway at ORNL to study such a system is discussed.

Adsorbate shape selectivity: Separation of the HF/134a azeotrope over carbogenic molecular sieve

Energy Technology Data Exchange (ETDEWEB)

Hong, A.; Mariwala, R.K.; Kane, M.S.; Foley, H.C. [Univ. of Delaware, Nework, DE (United States)

1995-03-01

Experimental evidence is provided for adsorptive shape selectivity in the separation of the azeotrope between HF and 1,1,1,2-tetrafluoroethane (134a) over pyrolyzed poly(furfuryl alcohol)-derived carbogenic molecular sieve (PPFA-CMS). The separation can be accomplished over coconut charcoal or Carbosieve G on the basis of the differences in the extent of equilibrium adsorption of HF and 134a. On these adsorbents 134a is more strongly bound than HF, thus it elutes much more slowly from the bed. The heat of adsorption for 134a in the vicinity of 200 C on Carbosieve G is {approximately}8.8 kcal/mol. In contrast, when the same azeotropic mixture is separated over PPFA-CMS prepared at 500 C, 134a is not adsorbed. As a result 134a elutes from the bed first, followed by HF. The reversal is brought about by the narrower pore size and pore size distribution of the PPFA-CMS versus that for Carbosieve G. Thus the separation over PPFA-CMS is an example of adsorbate shape selectivity and represents a limiting case of kinetic separation.

Measurement limits to 134Cs concentration in soil

International Nuclear Information System (INIS)

Ahn, J.K.; Kim, J.S.; Lee, H.M.; Kim, H.; Kim, T.H.; Park, J.N.; Kang, Y.S.; Lee, H.S.; Kim, S.J.; Park, J.Y.; Ryu, S.Y.; Kim, H.-Ch.; Kang, W.G.; Kim, S.K.

2011-01-01

We investigate the caesium concentrations in soils in mountain areas near Gori nuclear power plant in Korea, focusing on the measurement limits to the 134 Cs. In order to lower the minimum detectable amount (MDA) of activity for the 134 Cs, we have used the ammonium molybdophosphate (AMP) precipitation method to get rid of the 40 K existing in natural radioactivity, which reduces the MDA activity about 10 times smaller than those without the AMP precipitation method. The MDA results for the 134 Cs were found to be in the range between 0.015 and 0.044 Bq/kg-dry weight. In order to diminish the background, we also have measured a part of the soil samples in Yangyang, a small town in the east coast of Korea. However, it turns out that in order to detect the 134 Cs in the samples the MDA should be reduced to the level of mBq/kg-dry weight. - Highlights: → We study the caesium concentrations in soils in mountain areas near Gori NPT in Korea. → We use the AMP precipitation method to lower the minimum detectable amount (MDA) of activity for the 134 Cs. → The results of the MDA for the 134 Cs turn out to be in the range between 0.015 and 0.044. → In order to detect the 134 Cs in the samples, the MDA should be reduced to the level of mBq/kg-dry weight.

Dual-Mode Gas Sensor Composed of a Silicon Nanoribbon Field Effect Transistor and a Bulk Acoustic Wave Resonator: A Case Study in Freons

Directory of Open Access Journals (Sweden)

Ye Chang

2018-01-01

Full Text Available In this paper, we develop a novel dual-mode gas sensor system which comprises a silicon nanoribbon field effect transistor (Si-NR FET and a film bulk acoustic resonator (FBAR. We investigate their sensing characteristics using polar and nonpolar organic compounds, and demonstrate that polarity has a significant effect on the response of the Si-NR FET sensor, and only a minor effect on the FBAR sensor. In this dual-mode system, qualitative discrimination can be achieved by analyzing polarity with the Si-NR FET and quantitative concentration information can be obtained using a polymer-coated FBAR with a detection limit at the ppm level. The complementary performance of the sensing elements provides higher analytical efficiency. Additionally, a dual mixture of two types of freons (CFC-113 and HCFC-141b is further analyzed with the dual-mode gas sensor. Owing to the small size and complementary metal-oxide semiconductor (CMOS-compatibility of the system, the dual-mode gas sensor shows potential as a portable integrated sensing system for the analysis of gas mixtures in the future.

13 CFR 134.404 - Decision by Administrative Law Judge.

Science.gov (United States)

2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Decision by Administrative Law Judge. 134.404 Section 134.404 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION RULES OF... 8(a) Program § 134.404 Decision by Administrative Law Judge. Appeal proceedings brought under this...

29 CFR 1915.134 - Abrasive wheels.

Science.gov (United States)

2010-07-01

... 29 Labor 7 2010-07-01 2010-07-01 false Abrasive wheels. 1915.134 Section 1915.134 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... wheels shall fit freely on the spindle and shall not be forced on. The spindle nut shall be tightened...

Burnout experiments with 6 x 6, 8 x 8 and 7 x 7 rod bundle test sections using freon as model fluid

International Nuclear Information System (INIS)

Fulfs, H.; Katsaounis, A.; Minden, C.v.

1976-01-01

This paper reports on burnout experiments at staedy state condition using Freon12 as model fluid. The experiments were carried out with three test sections with 6 x 6, 8 x 8 and 7 x 7 rod bundles. The axial flux distribution of the rods is either constant or reactor like. The transformed measured points using STEVENS and BOURE scaling factors to equivalent water conditions respectively, were compared to the burnout correlation W3 using the reactor layout program DYNAMIT. The DYNAMIT code is a thermohydraulic lay-out reactor program without consideration of mixing flow between the subchannels. (orig.) [de

Heat transfer performance during condensation of R-134a inside helicoidal tubes

International Nuclear Information System (INIS)

Al-Hajeri, M.H.; Koluib, A.M.; Mosaad, M.; Al-Kulaib, S.

2007-01-01

This paper reports an experimental investigation of condensation heat transfer and pressure drop of an ozone friendly refrigerant, R-134a, inside a helical tube for climatic conditioning of hot regions. This study concerns the condensation of R-134a flowing through annular helical tubes with different operating refrigerant saturated temperatures. The average pressure drop is measured and compared with data from relevant literature. The measurements of R-134a were performed on mass flow flux ranges from 50 to 680 kg/m 2 s. The study provides experimental data that could be used for the design and development of more efficient condensers for refrigeration and air conditioning (A/C) systems working with the same refrigerant

Effect of Pelletized Coconut Fibre on the Compressive Strength of Foamed Concrete

Directory of Open Access Journals (Sweden)

Mohd Jaini Zainorizuan

2016-01-01

Full Text Available Foamed concrete is a controlled low density ranging from 400kg/m3 to 1800kg/m3, and hence suitable for the construction of buildings and infrastructures. The uniqueness of foamed concrete is does not use aggregates in order to retain low density. Foamed concrete contains only cement, sand, water and foam agent. Therefore, the consumption of cement is higher in producing a good quality and strength of foamed concrete. Without the present of aggregates, the compressive strength of foamed concrete can only achieve as high as 15MPa. Therefore, this study aims to introduce the pelletized coconut fibre aggregate to reduce the consumption of cement but able to enhance the compressive strength. In the experimental study, forty-five (45 cube samples of foamed concrete with density 1600kg/m3 were prepared with different volume fractions of pelletized coconut fibre aggregate. All cube samples were tested using the compression test to obtain compressive strength. The results showed that the compressive strength of foamed concrete containing 5%, 10%, 15% and 20% of pelletized coconut fibre aggregate are 9.6MPa, 11.4MPa, 14.6MPa and 13.4MPa respectively. It is in fact higher than the controlled foamed concrete that only achieves 9MPa. It is found that the pelletized coconut fibre aggregate indicates a good potential to enhance the compressive strength of foamed concrete.

Experimental determination of Henry's law constants of difluoromethane (HFC-32 and the salting-out effects in aqueous salt solutions relevant to seawater

Directory of Open Access Journals (Sweden)

S. Kutsuna

2017-06-01

Full Text Available Gas-to-water equilibrium coefficients, KeqS (in M atm−1, of difluoromethane (CH2F2, a hydrofluorocarbon refrigerant (HFC-32, in aqueous salt solutions relevant to seawater were determined over a temperature (T range from 276 to 313 K and a salinity (S range up to 51 ‰ by means of an inert-gas stripping method. From the van't Hoff equation, the KeqS value in water, which corresponds to the Henry's law constant (KH, at 298 K was determined to be 0.065 M atm−1. The salinity dependence of KeqS (the salting-out effect, ln(KH∕KeqS, did not obey the Sechenov equation but was proportional to S0. 5. Overall, the KeqS(T value was expressed by ln(KeqS(T  =  −49.71 + (77.70 − 0.134  ×  S0. 5  ×  (100∕T + 19.14  ×  ln(T∕100. By using this equation in a lower-tropospheric semi-hemisphere (30–90 °S of the Advanced Global Atmospheric Gases Experiment (AGAGE 12-box model, we estimated that 1 to 4 % of the atmospheric burden of CH2F2 resided in the ocean mixed layer and that this percentage was at least 4 % in the winter; dissolution of CH2F2 in the ocean may partially influence estimates of CH2F2 emissions from long-term observational data of atmospheric CH2F2 concentrations.

Environmental Assessment for Construction of a 20-Slip Boat Dock Structure MacDill AFB, Florida

Science.gov (United States)

2008-01-01

practice CAA Clean Air Act CCA chromated copper arsenate CEQ Council on Environmental Quality CES Civil Engineering Squadron CEV Environmental...newspaper advertisement in the April 10, 2007 edition of the Tampa Tribune announcing the availability of the Draft EA for public review at the John F...chlorine, freon, paints, thinners, oils, lubricants, compressed gases, pesticides, herbicides, nitrates, and chromates . A detailed tracking and accounting

Experimental Study of Flow Boiling Heat Transfer in a Horizontal Microfin Tube

OpenAIRE

Yu, Jian; Koyama, Shigeru; Momoki, Satoru

1995-01-01

An experimental study on flow boiling heat transfer in a horizontal microfin tube is conducted with pure refrigerants HFC134a, HCFC123 and HCFC22 using a water-heated double-tube type test section. The test microfin tube is a copper tube having the following dimensions: 8.37mm mean inside diameter, 0.168mm fin height, 60fin number and 18 degree of helix angle. The local heat transfer coefficients for both counter and parallel flows are measured in a range of heat flux of 1 to 93W/m^2, mass ve...

Hybrid compression/absorption type heat utilization system (eco-energy city project)

Energy Technology Data Exchange (ETDEWEB)

Karimata, T.; Susami, S.; Ogawa, Y. [Research and Development Dept., EBARA Corp., Kanagawa pref. (Japan)

1999-07-01

This research is intended to develop a 'hybrid compression/absorption type heat utilization system' by combining an absorption process with a compression process in one circulation cycle. This system can produce chilling heat for ice thermal storage by utilizing low-temperature waste heat (lower than 100 C) which is impossible to treat with a conventional absorption chiller. It means that this system will be able to solve the problem of a timing mismatch between waste heat and heat demand. The working fluid used in this proposed system should be suitable for producing ice, be safe, and not damage the ozone layer. In this project, new working fluids were searched as substitutes for the existing H{sub 2}O/LiBr or NH{sub 3}/H{sub 2}O. The interim results of this project in 1997, a testing unit using NH{sub 3}/H{sub 2}O was built for demonstration of the system and evaluation of its characteristics, and R134a/E181 was found to be one of the good working fluid for this system. The COP (ratio of energy of ice produced to electric power provided) of this system using R134a/E181 is expected to achieve 5.5 by computer simulation. The testing unit with this working fluid was built recently and prepared for the tests to confirm the result of the simulation. (orig.)

Direct and indirect contamination of tree crops with Cs-134

International Nuclear Information System (INIS)

Skarlou, V.; Nobeli, C.; Anoussis, J.; Arapis, G.; Haidouti, C.

1996-01-01

A long term glasshouse pot experiment was established in 1994 to study the transfer factors of Cs-134 from soil to olive and orange trees for which no relevant data are available. A calcareous-heavy textured and an acid-light textured soil were used in this experiment. Results from two year's experimentation are considered in this study. The ability of the studied plant species for Cs-134 root uptake seems to be significantly influenced by soil type. The contamination of both tree species grown on calcareous and heavy soil was very low and did not change much with the time. On the contrary, trees grown on acid and light soil showed much higher Cs-134 concentration (up to 34 times for orange and 23 for olive trees) which significantly increased with the time. Both olive and orange trees showed a similar behaviour in the studied soils. Effort was also made to study the long term consequences of the direct contamination in a field experiment where an olive tree was contaminated by dry deposition with Cs-134. Six months after contamination 5 % of the Cs-134 deposited on the leaves was measured in the first olive production. However, very small quantities (= 0.5 %) of the olive Cs-134 was detected in the unprocessed olive oil. The following year 15 % of the Cs-134 remained in the leaves while extremely low quantities of Cs-134 were detected in either olives or olive oil. (author)

Transient Increased Calcium and Calcitriol Requirements After Discontinuation of Human Synthetic Parathyroid Hormone 1-34 (hPTH 1-34) Replacement Therapy in Hypoparathyroidism.

Science.gov (United States)

Gafni, Rachel I; Guthrie, Lori C; Kelly, Marilyn H; Brillante, Beth A; Christie, C Michele; Reynolds, James C; Yovetich, Nancy A; James, Robert; Collins, Michael T

2015-11-01

Synthetic human PTH 1-34 (hPTH 1-34) replacement therapy in hypoparathyroidism maintains eucalcemia and converts quiescent bone to high-turnover bone. However, the skeletal and metabolic effects of drug discontinuation have not been reported. Nine subjects with hypoparathyroidism received subcutaneous injections of hPTH 1-34 two to three times daily for 19.8 to 61.3 months and then transitioned back to calcium and calcitriol. Biochemistries and bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) were assessed at baseline, while on treatment, and at follow-up 3 to 12 months after drug discontinuation. Two subjects developed hypocalcemia when hPTH 1-34 was abruptly discontinued. Thus, to avoid hypocalcemia, subjects were slowly weaned from hPTH 1-34 over several weeks. When hPTH 1-34 was stopped, subjects were requiring two to three times pretreatment doses of calcitriol and calcium to maintain blood calcium levels. Doses were gradually reduced over many weeks until calcium levels were stable on doses similar to baseline. Bone-specific alkaline phosphatase (BSAP), N-telopeptide (NTX), and osteocalcin (OC) increased significantly with hPTH 1-34; at follow-up, BSAP and NTX had returned to baseline while OC was still slightly elevated. During treatment, BMD was unchanged at the hip and lateral spine but declined at the anterior-posterior (AP) spine, radius, and total body. During weaning, BMD increased, with the hip and lateral spine exceeding pre-hPTH 1-34 values and the whole body returning to baseline. AP spine was increased non-significantly compared to baseline at follow-up. hPTH 1-34 must be gradually weaned in hypoparathyroid patients with high doses of oral medications given to avoid hypocalcemia. The transient increased requirements accompanied by increased BMD after long-term hPTH 1-34 therapy suggest a reversal of the expanded remodeling space favoring bone formation as the skeleton returns to a low-turnover state, reminiscent of the hungry

Implementation of R134a Thermophysical Properties for MARS Application

Energy Technology Data Exchange (ETDEWEB)

Son, Gyu Min; Bang, In Cheol [UNIST, Ulsan (Korea, Republic of)

2016-05-15

MARS requires 3 files for analysis: executable MARS file, input, and thermodynamic property file (tpf) for target fluids like light water or heavy water. Most experiments and scenarios were interested in behavior of water so original tpfs were sufficient enough for analysis. As MARS application became wider, needs for other fluid properties rose since MARS do not have extra function to interpret foreign materials that does not have tpf. One way of solving this problem is to generate external tpf file and if successfully implemented, this methodology could widen the application of MARS to other fields of engineering. Thus, this study aims for tpf generation of R134a. The reasons for its selection is because R134a is currently used in refrigerator and frequently used in flow boiling experiment related with heat transfer coefficient and CHF measurement. Generation methods of tpf were discussed. Conventional tpfh2o utilized Gibbs function to calculate the properties. However, since that method could not be applied to other fluids, fitting equation with temperature and pressure variables were applied from R134a property database. Direct implementation of theses equations simplified the structure of main program.

The absorption and distribution of Cesium-134 in rice-soil system

International Nuclear Information System (INIS)

Xu Yinliang; Chen Chuanqun; Chen Bin; Sun Zhiming

1991-01-01

Dynamics of absorption of 134 Cs by rice shows that absorption rate is the fastest at boot stage; absorption capacities of 134 Cs in soils are different with the different physical-chemical properties of soils; absorption amounts vary with the time of irrigating 134 Cs; the closer the irrigation time to mature stage is, the more the absorption amount of 134 Cs in rice will be; the more the irrigating times are, and the higher the radioactivity of 134 Cs in irrigating water is, the more the absorption amount in rice will be. After brown rice is polished, contamination of 134 Cs can be decreased by 22.6-45.6%. The order of specific activity in rice is: bran > root > straw > husk > polished rice. Percentage activity of straw, brown rice, root and husk is 51.4%, 28.4%, 11.8% and 8.4% respectively. The migration of 134 Cs is very slow in soil and 95.1% of 134 Cs is concentrated in surface soil (0-2.5 cm). The distribution ratio of 134 Cs in the rice and soil is 6.1%:93.9%. Potassium ion can inhibit the absorption of 134 Cs by rice. There is an exponential function between the concentration of potassium ion and specific activity of 134 Cs in rice

Fiscal 1997 survey report on the trend of global warming protection measures of substituting freons; 1997 nendo chosa hokokusho (daitai freon no chikyu ondanka taisaku doko ni kansuru chosa hokokusho)

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-03-01

The trend survey was conducted of global warming protection measures by participation in international conferences, scientific society meetings and lecture meetings, and by literature surveys. We participated in the international conference on ozonosphere protection measures. In the 9th meeting of the nations which concluded the Montreal Protocol, the strengthening of restrictions on methyl bromide was decided on. In the UNEP solvent technology selection conference and the OORG conference of the World Bank, reports were made on substituting solvents in Japan, activities supporting developing countries, and the developmental trend of urethane use foaming agent. In the international conference on ozonosphere protection measures, introduced were the present status of Japan`s ODA for developing countries and examples of success of the substitution in the solvent field. The paper included nine reports on CFC destruction technology related literature made public in the past one year. The paper also introduced a comparative study of de-HCFC substituting technology at U.S. Oak Ridge National Laboratory, U.S. EPA`s prediction of emission of fluorine 3 gas, the predicted value of HFC emission and trial calculation of contributing rate in all greenhouse gases by IIR, Green Peace and Elf Atochem, and NOAA`s measured data on SF6 in the atmosphere. 49 refs., 46 figs., 26 tabs.

13 CFR 134.209 - Requirement of signature.

Science.gov (United States)

2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Requirement of signature. 134.209 Section 134.209 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION RULES OF PROCEDURE GOVERNING... of signature. Every written submission to OHA, other than evidence, must be signed by the party...

13 CFR 134.702 - Who may appeal?

Science.gov (United States)

2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Who may appeal? 134.702 Section 134.702 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION RULES OF PROCEDURE GOVERNING CASES BEFORE THE OFFICE OF HEARINGS AND APPEALS Rules of Practice for Appeals From Women-Owned Small...

DNABIT Compress - Genome compression algorithm.

Science.gov (United States)

Rajarajeswari, Pothuraju; Apparao, Allam

2011-01-22

Data compression is concerned with how information is organized in data. Efficient storage means removal of redundancy from the data being stored in the DNA molecule. Data compression algorithms remove redundancy and are used to understand biologically important molecules. We present a compression algorithm, "DNABIT Compress" for DNA sequences based on a novel algorithm of assigning binary bits for smaller segments of DNA bases to compress both repetitive and non repetitive DNA sequence. Our proposed algorithm achieves the best compression ratio for DNA sequences for larger genome. Significantly better compression results show that "DNABIT Compress" algorithm is the best among the remaining compression algorithms. While achieving the best compression ratios for DNA sequences (Genomes),our new DNABIT Compress algorithm significantly improves the running time of all previous DNA compression programs. Assigning binary bits (Unique BIT CODE) for (Exact Repeats, Reverse Repeats) fragments of DNA sequence is also a unique concept introduced in this algorithm for the first time in DNA compression. This proposed new algorithm could achieve the best compression ratio as much as 1.58 bits/bases where the existing best methods could not achieve a ratio less than 1.72 bits/bases.

Cooling performance and energy saving of a compression-absorption refrigeration system assisted by geothermal energy

International Nuclear Information System (INIS)

Kairouani, L.; Nehdi, E.

2006-01-01

The objectives of this paper are to develop a novel combined refrigeration system, and to discuss the thermodynamic analysis of the cycle and the feasibility of its practical development. The aim of this work was to study the possibility of using geothermal energy to supply vapour absorption system cascaded with conventional compression system. Three working fluids (R717, R22, and R134a) are selected for the conventional compression system and the ammonia-water pair for the absorption system. The geothermal temperature source in the range 343-349 K supplies a generator operating at 335 K. Results show that the COP of a combined system is significantly higher than that of a single stage refrigeration system. It is found that the COP can be improved by 37-54%, compared with the conventional cycle, under the same operating conditions, that is an evaporation temperature at 263 K and a condensation temperature of 308 K. For industrial refrigeration, the proposed system constitutes an alternative solution for reducing energy consumption and greenhouse gas emissions

42 CFR 84.134 - Respirator containers; minimum requirements.

Science.gov (United States)

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Respirator containers; minimum requirements. 84.134... Respirators § 84.134 Respirator containers; minimum requirements. Supplied-air respirators shall be equipped with a substantial, durable container bearing markings which show the applicant's name, the type and...

9 CFR 3.134-3.135 - [Reserved

Science.gov (United States)

2010-01-01

... Warmblooded Animals Other Than Dogs, Cats, Rabbits, Hamsters, Guinea Pigs, Nonhuman Primates, and Marine... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false [Reserved] 3.134-3.135 Section 3.134-3.135 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...

134Cs emission probabilities determination by gamma spectrometry

Science.gov (United States)

de Almeida, M. C. M.; Poledna, R.; Delgado, J. U.; Silva, R. L.; Araujo, M. T. F.; da Silva, C. J.

2018-03-01

The National Laboratory for Ionizing Radiation Metrology (LNMRI/IRD/CNEN) of Rio de Janeiro performed primary and secondary standardization of different radionuclides reaching satisfactory uncertainties. A solution of 134Cs radionuclide was purchased from commercial supplier to emission probabilities determination of some of its energies. 134Cs is a beta gamma emitter with 754 days of half-life. This radionuclide is used as standard in environmental, water and food control. It is also important to germanium detector calibration. The gamma emission probabilities (Pγ) were determined mainly for some energies of the 134Cs by efficiency curve method and the Pγ absolute uncertainties obtained were below 1% (k=1).

22 CFR 134.30 - Payment of award.

Science.gov (United States)

2010-04-01

... will pay the amount awarded to the applicant within 60 days, unless judicial review of the award or of... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Payment of award. 134.30 Section 134.30 Foreign Relations DEPARTMENT OF STATE MISCELLANEOUS EQUAL ACCESS TO JUSTICE ACT; IMPLEMENTATION Procedures for...

40 CFR 86.134-96 - Running loss test.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Running loss test. 86.134-96 Section... Heavy-Duty Vehicles; Test Procedures § 86.134-96 Running loss test. (a) Overview. Gasoline- and methanol-fueled vehicles are to be tested for running loss emissions during simulated high-temperature urban...

International research into chlorofluorocarbon (CFC) alternatives

Energy Technology Data Exchange (ETDEWEB)

Marseille, T.J.; Shankle, D.L.; Thurman, A.G.

1992-05-01

Selected researchers from 21 countries were queried through questionnaires about their current and planned research activities. The results of the survey show that the majority of research being conducted by the respondents is devoted to investigating the hydrogenated fluorocarbon HFC-134a as a replacement for CFC-12 in refrigeration applications. The main issue with this alternative is identifying compatible lubricants that do not reduce its effectiveness.

An examination of the influence of spacers on burnout in an annulus cooled by the upflow of Freon-12

International Nuclear Information System (INIS)

Ilic, V.

1975-04-01

To evaluate the spacer influence on burnout, tests were carried out in Freon-12 at 1.04 MPa (abs.) test section inlet pressure with an internally heated annulus 2743 mm long by 14.4 mm heater diameter, the outer tube (shroud) having a bore of 22.1 mm. The inner rod (heater) was located centrally to the shroud by spacers and their configuration was changed for each test. Comparison of the results with those obtained with a test section having no spacers indicated that spacers can increase burnout power up to 75 per cent, decrease it, or show no effect at all, depending on the combination of the inlet temperature and mass velocity. If the spacers were streamlined, removed from the upstream portion of the heater or relocated farther upstream from the downstream end of the heater, there was a considerably reduced effect on the test section performance. (author)

41 CFR 105-53.134 - Office of Administration.

Science.gov (United States)

2010-07-01

... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Office of Administration. 105-53.134 Section 105-53.134 Public Contracts and Property Management Federal Property Management... Associate Administrator for Administration, participates in the executive leadership of the agency...

EXPERIMENTAL INVESTIGATION OF R-134a AND R-600a ...

African Journals Online (AJOL)

Preet khandelwal

performance of blends of two existing refrigerant, R-134a and R-600a, blended together at ratios of 11%/89%, ... blending ratios, estimated GWPs ≤ 150 using Ali's model. .... series are less flammable among other HCs and its .... Figure 2: Variation of Evaporator Temperature with Time at an Ambient Temperature of 37oC.

Thermoeconomic optimization of subcooled and superheated vapor compression refrigeration cycle

International Nuclear Information System (INIS)

Selbas, Resat; Kizilkan, Onder; Sencan, Arzu

2006-01-01

An exergy-based thermoeconomic optimization application is applied to a subcooled and superheated vapor compression refrigeration system. The advantage of using the exergy method of thermoeconomic optimization is that various elements of the system-i.e., condenser, evaporator, subcooling and superheating heat exchangers-can be optimized on their own. The application consists of determining the optimum heat exchanger areas with the corresponding optimum subcooling and superheating temperatures. A cost function is specified for the optimum conditions. All calculations are made for three refrigerants: R22, R134a, and R407c. Thermodynamic properties of refrigerants are formulated using the Artificial Neural Network methodology

DNABIT Compress – Genome compression algorithm

Science.gov (United States)

Rajarajeswari, Pothuraju; Apparao, Allam

2011-01-01

Data compression is concerned with how information is organized in data. Efficient storage means removal of redundancy from the data being stored in the DNA molecule. Data compression algorithms remove redundancy and are used to understand biologically important molecules. We present a compression algorithm, “DNABIT Compress” for DNA sequences based on a novel algorithm of assigning binary bits for smaller segments of DNA bases to compress both repetitive and non repetitive DNA sequence. Our proposed algorithm achieves the best compression ratio for DNA sequences for larger genome. Significantly better compression results show that “DNABIT Compress” algorithm is the best among the remaining compression algorithms. While achieving the best compression ratios for DNA sequences (Genomes),our new DNABIT Compress algorithm significantly improves the running time of all previous DNA compression programs. Assigning binary bits (Unique BIT CODE) for (Exact Repeats, Reverse Repeats) fragments of DNA sequence is also a unique concept introduced in this algorithm for the first time in DNA compression. This proposed new algorithm could achieve the best compression ratio as much as 1.58 bits/bases where the existing best methods could not achieve a ratio less than 1.72 bits/bases. PMID:21383923

Experimental study on void fraction of two-phase flow inside a micro-fin tube

OpenAIRE

Koyama, Shigeru; Chen, Yongchang; Kitano, Ryuji; Kuwahara, Ken

2001-01-01

In this paper the void fraction and flow pattern of the two-phase flow in a micro-fin tube were investigated experimentally for a pure refrigerant HFC134a. The experiment was carried out at a pressure range of 0.6 and 1.2MPa with mass velocities of 90 and 180kg/m^2 s, in which the vapor quality varied from 0 to 1. The void fraction was measured by means of simultaneously closing valves of both sides of the test tube at adiabatic condition. Experimental results for the micro-fin tube were comp...

19 CFR 134.43 - Methods of marking specific articles.

Science.gov (United States)

2010-04-01

... 19 Customs Duties 1 2010-04-01 2010-04-01 false Methods of marking specific articles. 134.43...; DEPARTMENT OF THE TREASURY COUNTRY OF ORIGIN MARKING Method and Location of Marking Imported Articles § 134.43 Methods of marking specific articles. (a) Marking previously required by certain provisions of the...

Assessment of propane/commercial butane mixtures as possible alternatives to R134a in domestic refrigerators

International Nuclear Information System (INIS)

Fatouh, M.; El Kafafy, M.

2006-01-01

The possibility of using hydrocarbon mixtures as working fluids to replace R134a in domestic refrigerators has been evaluated through a simulation analysis in the present work. The performance characteristics of domestic refrigerators were predicted over a wide range of evaporation temperatures (-35 to -10 o C) and condensation temperatures (40-60 deg. C) for various working fluids such as R134a, propane, commercial butane and propane/iso-butane/n-butane mixtures with various propane mass fractions. The performance characteristics of the considered domestic refrigerator were identified by the coefficient of performance (COP), volumetric cooling capacity, cooling capacity, condenser capacity, input power to compressor, discharge temperature, pressure ratio and refrigerant mass flow rate. The results showed that pure propane could not be used as a drop in replacement for R134a in domestic refrigerators because of its high operating pressures and low COP. Commercial butane yields many desirable characteristics but requires a compressor change. The coefficient of performance of the domestic refrigerator using a ternary hydrocarbon mixture with propane mass fractions from 0.5 to 0.7 is higher than that of R134a. Comparison among the considered working fluids confirmed that the average refrigerant mass flow rate of the propoane/commercial butane mixture is 50% lower than that of R134a. Also, the results indicated that R134a and the propoane/commercial butane mixture with 60% propane mass concentration have approximately the same values of saturation pressure, compressor discharge temperature, condenser heat load, input power, cooling capacity and volumetric cooling capacity. However, the pressure ratio of the hydrocarbon mixture with 60% propane is lower than that of R134a by about 11.1%. Finally, the reported results confirmed that the propane/iso-butane/n-butane mixture with 60% propane is the best drop in replacement for R134a in domestic refrigerators under normal

MicroRNA-134 regulates poliovirus replication by IRES targeting

OpenAIRE

Bakre, Abhijeet A.; Shim, Byoung-Shik; Tripp, Ralph A.

2017-01-01

Global poliovirus eradication efforts include high vaccination coverage with live oral polio vaccine (OPV), surveillance for acute flaccid paralysis, and OPV “mop-up” campaigns. An important objective involves host-directed strategies to reduce PV replication to diminish viral shedding in OPV recipients. In this study, we show that microRNA-134-5p (miR-134) can regulate Sabin-1 replication but not Sabin-2 or Sabin-3 via direct interaction with the PV 5′UTR. Hypochromicity data showed miR-134 ...

134Cs in heather seed plants grown with and without mycorrhiza

International Nuclear Information System (INIS)

Strandberg, M.; Johansson, M.

1988-01-01

Experiments were carried out to determine differences between mycorrhized and non-mycorrhized seed plants of heather, Calluna vulgaris(L)Hull, as regards the uptake of 134 Cs. In most treatments heather with mycorrhiza had a significantly higher transfer of 134 Cs to the shoots than heather without mycorrhiza. As an average the concentration of 134 Cs was 18% higher in the mycorrhized plants than in the non-mycorrhized. Application of 10 kg K/ha reduced the concentration of 134 Cs in shoots of heather by 49% as an average. Because of improved growth in the potassium fertilized pots the reduction viewed on the basis of the area was only 33%. Nitrogen application does not significantly influence the concentration of 134 Cs in shoots of heather regardless of mycorrhizal status. (Copyright (c) 1988 Elsevier Science B.V., Amsterdam. All rights reserved.)

19 CFR 134.54 - Articles released from Customs custody.

Science.gov (United States)

2010-04-01

... 19 Customs Duties 1 2010-04-01 2010-04-01 false Articles released from Customs custody. 134.54...; DEPARTMENT OF THE TREASURY COUNTRY OF ORIGIN MARKING Articles Found Not Legally Marked § 134.54 Articles... value of the articles not properly marked or redelivered. (b) Failure to petition for relief. A written...

The impact of chest compression rates on quality of chest compressions - a manikin study.

Science.gov (United States)

Field, Richard A; Soar, Jasmeet; Davies, Robin P; Akhtar, Naheed; Perkins, Gavin D

2012-03-01

Chest compressions are often performed at a variable rate during cardiopulmonary resuscitation (CPR). The effect of compression rate on other chest compression quality variables (compression depth, duty-cycle, leaning, performance decay over time) is unknown. This randomised controlled cross-over manikin study examined the effect of different compression rates on the other chest compression quality variables. Twenty healthcare professionals performed 2 min of continuous compressions on an instrumented manikin at rates of 80, 100, 120, 140 and 160 min(-1) in a random order. An electronic metronome was used to guide compression rate. Compression data were analysed by repeated measures ANOVA and are presented as mean (SD). Non-parametric data was analysed by Friedman test. At faster compression rates there were significant improvements in the number of compressions delivered (160(2) at 80 min(-1) vs. 312(13) compressions at 160 min(-1), P<0.001); and compression duty-cycle (43(6)% at 80 min(-1) vs. 50(7)% at 160 min(-1), P<0.001). This was at the cost of a significant reduction in compression depth (39.5(10)mm at 80 min(-1) vs. 34.5(11)mm at 160 min(-1), P<0.001); and earlier decay in compression quality (median decay point 120 s at 80 min(-1) vs. 40s at 160 min(-1), P<0.001). Additionally not all participants achieved the target rate (100% at 80 min(-1) vs. 70% at 160 min(-1)). Rates above 120 min(-1) had the greatest impact on reducing chest compression quality. For Guidelines 2005 trained rescuers, a chest compression rate of 100-120 min(-1) for 2 min is feasible whilst maintaining adequate chest compression quality in terms of depth, duty-cycle, leaning, and decay in compression performance. Further studies are needed to assess the impact of the Guidelines 2010 recommendation for deeper and faster chest compressions. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

{sup 134}Cs emission probabilities determination by gamma spectrometry

Energy Technology Data Exchange (ETDEWEB)

Almeida, M.C.M. de, E-mail: candida@cnen.gov.br [Comissão Nacional de Energia Nuclear (DINOR/CNEN), Riode Janeiro, RJ (Brazil); Poledna, R.; Delgado, J.U.; Silva, R.L.; Araujo, M.T.; Silva, C.J. da [Instituto de Radioproteção e Dosimetria (LNMRI/IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

2017-07-01

The National Laboratory for Ionizing Radiation Metrology (LNMRI/IRD/CNEN) of Rio de Janeiro performed primary and secondary standardization of different radionuclides reaching satisfactory uncertainties. A solution of {sup 134}Cs radionuclide was purchased from commercial supplier to emission probabilities determination of some of its energies. {sup 134}Cs is a beta gamma emitter with 754 days of half-life. This radionuclide is used as standard in environmental, water and food control. It is also important to germanium detector calibration.The gamma emission probabilities (Pγ) were determined mainly for some energies of the {sup 134}Cs by efficiency curve method and the Pγ absolute uncertainties obtained were below 1% (k=1). (author)

R134a Flow Boiling Analysis with Modified Thermodynamic Property File of MARS Code

Energy Technology Data Exchange (ETDEWEB)

Son, Gyumin; Bang, In Cheol [UNIST, Ulsan (Korea, Republic of)

2016-10-15

Previous study showed application of RELAP5 code to solar energy facility with molten salt (60% NaNO3 and 40% KNO3) as working fluid. Based on external experimental correlations, thermodynamic properties of molten salt were evaluated as a function of pressure and temperature and those equations were used to generate tpf. To validate external tpf, experimental values were compared with RELAP5 analysis. In nuclear field, utilization of other fluid is also important since many thermal-hydraulic experiments used various fluids such as FC-72, R123, and R134a. Theses refrigerants have been used to simulate the high pressure environment of nuclear power plants due to their low boiling point, and density ratio between vapor and liquid. Thus, this study aims for tpf generation of R134a and verification by analyzing real case. R134a is selected as a fluid to be implemented and analyzed because it is currently used in refrigerator and frequently used in flow boiling experiment related with heat transfer coefficient and CHF measurement. R134a property file were generated with fitted equation using temperature and pressure as variables, originated from external data source. For validation, flow boiling experiment case were made into simplified input. Analysis with tpfr134a showed that application of Gnielinksi correlation could enhance single phase flow accuracy. Large error of HTC from two phase analysis requires parameter study. Future work aims for more specified experimental case comparison and correlation enhancement for two phase analysis.

13 CFR 134.405 - Jurisdiction.

Science.gov (United States)

2010-01-01

... Jurisdiction. (a) The Administrative Law Judge selected to preside over an appeal shall decline to accept... disadvantage, economic disadvantage, ownership or control; (2) The appeal is untimely filed under § 134.202 or... before a court of competent jurisdiction over such matters. (b) Once the Administrative Law Judge accepts...

40 CFR 81.134 - Austin-Waco Intrastate Air Quality Control Region.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Austin-Waco Intrastate Air Quality Control Region. 81.134 Section 81.134 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Quality Control Regions § 81.134 Austin-Waco Intrastate Air Quality Control Region. The Austin-Waco...

A Novel Application of Thermoelectric Modules in an HVAC System Under Cold Climate Operation

Science.gov (United States)

Okuma, Toru; Radermacher, Reinhard; Hwang, Yunho

2012-06-01

A vapor compression cycle (VCC) with integrated thermoelectric (TE) modules to boost the heating capacity of the system in an energy-efficient way, especially for cold climate operation, is suggested in this paper. While a baseline heat pump (HP) cycle absorbs heat from a source through an evaporator, the proposed system utilizes TE modules as an intermediate (or third) stage of an otherwise two-stage vapor compression system with a vapor injection compressor. This increases the overall system efficiency and augments the system capacity through the high coefficient of performance (COP) of the TE for small temperature lift conditions. To demonstrate the concept, a prototype refrigerant-to-solid (TE) heat exchanger, consisting of TE modules and microchannel flat tubes, was designed and fabricated so that the whole system could realize an additional 1 kW of heating capacity compared with the baseline system. The TE heat exchanger was integrated into a residential HP unit that uses R-410A as a refrigerant, and the system was tested in a laboratory under the severe condition of -17.8°C, in order to investigate the capacity improvement and the overall COP. Finally, an application of this technique in an automotive heating, ventilating, and air-conditioning system with HFC134a working fluid has been studied for the purpose of providing supplemental heating for electric vehicles and hybrid electric vehicles by establishing a detailed simulation model of a HP system with the TE heat exchanger. Both the laboratory test and the calculation study show that a VCC with integrated TE modules has both reasonable efficiency and increased heating capacity.

24 CFR 17.134 - Procedures for salary offset: when deductions may begin.

Science.gov (United States)

2010-04-01

... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Procedures for salary offset: when deductions may begin. 17.134 Section 17.134 Housing and Urban Development Office of the Secretary, Department... Government Salary Offset Provisions § 17.134 Procedures for salary offset: when deductions may begin. (a...

Radiogenotoxicological effect of signal nuclide 134Cs on somatic and germ cells

Institute of Scientific and Technical Information of China (English)

ZhuShou－Peng; XiaFen; 等

1997-01-01

Chromosome at aberation rates in bone marrow cells and micronucleus formation in bone marrow polychromatic erythrocytes both rise with increase in radioactivities of 134Cs,and can be fitted to power functions of radioactivities of 134Cs.In spermatogonia 134Cs mainly induced chromatid breakage,and abnormalities in sperm can also be experessed as power functions of radioactivities of 134 Cs.

Predicting heat transfer in long, R-134a filled thermosyphons

NARCIS (Netherlands)

Grooten, M.H.M.; Geld, van der C.W.M.

2008-01-01

When traditional air-to-air cooling is too voluminous, heat exchangers with long thermosyphons offer a good alternative. Experiments with a single thermosyphon with a large length-to-diameter ratio (188) and filled with R-134a are presented and analyzed. Saturation temperatures, filling ratios, and

The impact of chest compression rates on quality of chest compressions : a manikin study

OpenAIRE

Field, Richard A.; Soar, Jasmeet; Davies, Robin P.; Akhtar, Naheed; Perkins, Gavin D.

2012-01-01

Purpose\\ud Chest compressions are often performed at a variable rate during cardiopulmonary resuscitation (CPR). The effect of compression rate on other chest compression quality variables (compression depth, duty-cycle, leaning, performance decay over time) is unknown. This randomised controlled cross-over manikin study examined the effect of different compression rates on the other chest compression quality variables.\\ud Methods\\ud Twenty healthcare professionals performed two minutes of co...

Correlation of MR tomographic findings and microvascular decompression treatment of the neurovascular compressions of the cranial nerves

International Nuclear Information System (INIS)

Liu Zengsheng; Chen Xiangmin; Sun Yiyan; Fang Ming; Wang Ping; Guan Yong; Sun Miao

2010-01-01

Objective: To explore the correlation of the operation effects of the miorovascular decompression (MVD) and the findings on magnetic resonance tomographie angiography (MRTA) in patients of neurovascular compression of the cranial nerves. Methods: Two hundred and twenty three patients treated with the microvascular decompression were analyzed retrospectively. They were grouped and graded according to the vessel compression on the cranial nerves. The compression were grouped as none, moderate and severe, and the operation effects were graded as I (complete relief), II (partial relief) and III ( no relief). The operation effects grades were correlated according to the compression groups by Kruskal-Wallis test and the operation effects between each two of the groups were compared using Nemenyi test. P 2 =16.84 and P<0.05. The mean rank of the non-compression, the moderate and the severe group was 134.21,102.37 and 110.4, respectively. The difference of the mean ranks between the non-compression group and the moderate group was 31.84, and between the non-compression and the severe group was 24.17, respectively, where P<0.05 both. Conclusions: There was close relationship between the findings on magnetic resonance tomographic angiography and the operation effects of the MVD. The operation effects of patients with moderate and severe vessel compression were much better than the non-compression group. MRTA is helpful for MVD surgical indication and its prognosis. (authors)

[Lens luxation in dogs: a retrospective study of 134 dogs (2000-2011)].

Science.gov (United States)

Betschart; Hässig; Spiess

2014-03-01

This retrospective study evaluated cases of lens luxation in dogs that were documented at the University of Zurich Veterinary Teaching Hospital between 2000 and 2011. A total 134 dogs were included in the study. This population of dogs with lens luxation represents 0.41 % of all dogs presented to the Zurich Veterinary Teaching Hospital (32'523) and 3.02 % of all dogs presented to the ophthalmology service during the same time period. The 134 dogs represented over 40 different breeds, including mixed breeds. 63 of the dogs were male, 71 were female. The 134 dogs were divided in primary lens luxation (86 of the 134 dogs, 64 %) and secondary lens luxation (48 dogs, 36 %). The most frequent causes for secondary lens luxation were glaucoma (58 %), cataract (19 %) and trauma (17 %). This study shows the predisposition for primary lens luxations in terrier breeds, Chinese Crested dogs, Pinscher and Spitz. In contrast, Siberian Huskies, Basset Hounds, Bearded Collies, Cairn Terriers, mixed breed dogs, Bolonka Zwetna, Boston Terriers, Borzoi, Doberman, Eurasian, Leonberg, Luzerner Niederlaufhund and Weimaraner suffered significantly more often from secondary lens luxation. There was no sex predilection for primary or secondary lens luxation. Dogs with primary lens luxation were on average 7.39 ± 3.02 years old, which is significantly younger than the dogs with secondary lens luxation (9.12 ± 3.38 years). Dogs with primary lens luxation showed a significantly higher rate of a bilateral development than those with secondary lens luxation (85.5 % of the dogs with primary lens luxation and only 14.5 % of the dogs with secondary lens luxation showed it in both their eyes).

MicroRNA hsa-miR-134 is a circulating biomarker for mesial temporal lobe epilepsy.

Directory of Open Access Journals (Sweden)

Simoni H Avansini

Full Text Available Epilepsy is misdiagnosed in up to 25% of patients, leading to serious and long-lasting consequences. Recently, circulating microRNAs have emerged as potential biomarkers in a number of clinical scenarios. The purpose of this study was to identify and to validate circulating microRNAs that could be used as biomarkers in the diagnosis of epilepsy. Quantitative real-time PCR was used to measure plasma levels of three candidate microRNAs in two phases of study: an initial discovery phase with 14 patients with mesial temporal lobe epilepsy (MTLE, 13 with focal cortical dysplasia (FCD and 16 controls; and a validation cohort constituted of an independent cohort of 65 patients with MTLE and 83 controls. We found hsa-miR-134 downregulated in patients with MTLE (p = 0.018 but not in patients with FCD, when compared to controls. Furthermore, hsa-miR-134 expression could be used to discriminate MTLE patients with an area under the curve (AUC of 0.75. To further assess the robustness of hsa-miR-134 as a biomarker for MTLE, we studied an independent cohort of 65 patients with MTLE, 27 of whom MTLE patients were responsive to pharmacotherapy, and 38 patients were pharmacoresistant and 83 controls. We confirmed that hsa-miR-134 was significantly downregulated in the plasma of patients with MTLE when compared with controls (p < 0.001. In addition, hsa-miR-134 identified patients with MTLE regardless of their response to pharmacotherapy or the presence of MRI signs of hippocampal sclerosis. We revealed that decreased expression of hsa-miR-134 could be a potential non-invasive biomarker to support the diagnosis of patients with MTLE.

Dimensioning of flanged heat exchangers using the CYRANO software: pure refrigerants and mixtures; Dimensionnement des batteries a ailettes a l`aide du logiciel CYRANO: frigorigenes purs et melanges

Energy Technology Data Exchange (ETDEWEB)

Bensafi, A; Borg, S [CETIAT, Centre Technique des Industries Aerauliques et Thermiques, 69 - Villeurbanne (France)

1998-12-31

A software for the dimensioning and simulation of flanged heat exchangers is presented. This software divides the exchanger into pipe sections in which local values of physical properties of fluids and thermal exchange coefficients are used, and for which individual thermal-hydraulic performances are determined. CYRANO can be used for condensers, evaporators and monophase exchanges, with refrigerants like water, R22, R134a and R32/R125/R134a mixtures. The software can be used also in the case of specified complex circuits, equipped with smooth or grooved pipes and with smooth continuous, corrugated or slatted flanges with non-homogeneous air temperature and velocity distributions. The validation of CYRANO was performed on 7 exchangers with and without humidity condensation on the flanges. Comparisons with test results show that the average of errors in exchanged powers is of about 5%, and of about 30% in the case of internal pressure drops. Some simulations of exchangers with HFC mixtures are also presented. (J.S.) 34 refs.

Dimensioning of flanged heat exchangers using the CYRANO software: pure refrigerants and mixtures; Dimensionnement des batteries a ailettes a l`aide du logiciel CYRANO: frigorigenes purs et melanges

Energy Technology Data Exchange (ETDEWEB)

Bensafi, A.; Borg, S. [CETIAT, Centre Technique des Industries Aerauliques et Thermiques, 69 - Villeurbanne (France)

1997-12-31

A software for the dimensioning and simulation of flanged heat exchangers is presented. This software divides the exchanger into pipe sections in which local values of physical properties of fluids and thermal exchange coefficients are used, and for which individual thermal-hydraulic performances are determined. CYRANO can be used for condensers, evaporators and monophase exchanges, with refrigerants like water, R22, R134a and R32/R125/R134a mixtures. The software can be used also in the case of specified complex circuits, equipped with smooth or grooved pipes and with smooth continuous, corrugated or slatted flanges with non-homogeneous air temperature and velocity distributions. The validation of CYRANO was performed on 7 exchangers with and without humidity condensation on the flanges. Comparisons with test results show that the average of errors in exchanged powers is of about 5%, and of about 30% in the case of internal pressure drops. Some simulations of exchangers with HFC mixtures are also presented. (J.S.) 34 refs.

13 CFR 134.218 - Judges.

Science.gov (United States)

2010-01-01

... Administrative Law Judge. The AA/OHA will assign all other cases before OHA to either an Administrative Law Judge... Business Credit and Assistance SMALL BUSINESS ADMINISTRATION RULES OF PROCEDURE GOVERNING CASES BEFORE THE OFFICE OF HEARINGS AND APPEALS Rules of Practice for Most Cases § 134.218 Judges. (a) Assignment. The AA...

32 CFR 13.4 - Duties and responsibilities of the defense.

Science.gov (United States)

2010-07-01

... COMMISSIONS RESPONSIBILITIES OF THE CHIEF DEFENSE COUNSEL, DETAILED DEFENSE COUNSEL, AND CIVILIAN DEFENSE COUNSEL § 13.4 Duties and responsibilities of the defense. (a) Regular duties. The Defense shall perform... 32 National Defense 1 2010-07-01 2010-07-01 false Duties and responsibilities of the defense. 13.4...

Thermofluidic compression effects to achieve combustion in a low-compression scramjet engine

Science.gov (United States)

Moura, A. F.; Wheatley, V.; Jahn, I.

2017-12-01

The compression provided by a scramjet inlet is an important parameter in its design. It must be low enough to limit thermal and structural loads and stagnation pressure losses, but high enough to provide the conditions favourable for combustion. Inlets are typically designed to achieve sufficient compression without accounting for the fluidic, and subsequently thermal, compression provided by the fuel injection, which can enable robust combustion in a low-compression engine. This is investigated using Reynolds-averaged Navier-Stokes numerical simulations of a simplified scramjet engine designed to have insufficient compression to auto-ignite fuel in the absence of thermofluidic compression. The engine was designed with a wide rectangular combustor and a single centrally located injector, in order to reduce three-dimensional effects of the walls on the fuel plume. By varying the injected mass flow rate of hydrogen fuel (equivalence ratios of 0.22, 0.17, and 0.13), it is demonstrated that higher equivalence ratios lead to earlier ignition and more rapid combustion, even though mean conditions in the combustor change by no more than 5% for pressure and 3% for temperature with higher equivalence ratio. By supplementing the lower equivalence ratio with helium to achieve a higher mass flow rate, it is confirmed that these benefits are primarily due to the local compression provided by the extra injected mass. Investigation of the conditions around the fuel plume indicated two connected mechanisms. The higher mass flow rate for higher equivalence ratios generated a stronger injector bow shock that compresses the free-stream gas, increasing OH radical production and promoting ignition. This was observed both in the higher equivalence ratio case and in the case with helium. This earlier ignition led to increased temperature and pressure downstream and, consequently, stronger combustion. The heat release from combustion provided thermal compression in the combustor, further

Plant uptake of 134Cs in relation to soil properties and time

International Nuclear Information System (INIS)

Massas, I.; Skarlou, V.; Haidouti, C.

2002-01-01

134 Cs uptake by sunflower and soybean plants grown on seven different soils and its relation to soil properties were studied in a greenhouse pot experiment. Soil in each pot was contaminated by dripping the 134 Cs in layers, and sunflower and soybean plants were grown for three and two successive periods, respectively. 134 Cs plant uptake was expressed as the transfer factor (TF) (Bq kg -1 plant/Bq kg -1 soil) and as the daily plant uptake (flux) (Bq pot -1 day -1 ) taking into account biomass production and growth time. For the studied soils and for both plants, no consistent trend of TFs with time was observed. The use of fluxes, in general, provided less variable results than TFs and stronger functional relationships. A negative power functional relationship between exchangeable potassium plus ammonium cations expressed as a percentage of cation exchange capacity of each soil and 134 Cs fluxes was found for the sunflower plants. A similar but weaker relationship was observed for soybean plants. The significant correlation between sunflower and soybean TFs and fluxes, as well as the almost identical highest/lowest 134 Cs flux ratios, in the studied soils, indicated a similar effect of soil characteristics on 134 Cs uptake by both plants. In all the studied soils, sunflower 134 Cs TFs and fluxes were significantly higher than the respective soybean values, while no significant difference was observed in potassium content and daily potassium plant uptake (flux) of the two plants

A simple method for the deconvolution of 134 Cs/137 Cs peaks in gamma-ray scintillation spectrometry

International Nuclear Information System (INIS)

Darko, E.O.; Osae, E.K.; Schandorf, C.

1998-01-01

A simple method for the deconvolution of 134 Cs / 137 Cs peaks in a given mixture of 134 Cs and 137 Cs using Nal(TI) gamma-ray scintillation spectrometry is described. In this method the 795 keV energy of 134 Cs is used as a reference peak to calculate the activity of the 137 Cs directly from the measured peaks. Certified reference materials were measured using the method and compared with a high resolution gamma-ray spectrometry measurements. The results showed good agreement with the certified values. The method is very simple and does not need any complicated mathematics and computer programme to de- convolute the overlapping 604.7 keV and 661.6 keV peaks of 134 Cs and 137 Cs respectively. (author). 14 refs.; 1 tab., 2 figs

13 CFR 134.713 - When is the record closed?

Science.gov (United States)

2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false When is the record closed? 134.713 Section 134.713 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION RULES OF PROCEDURE GOVERNING CASES BEFORE THE OFFICE OF HEARINGS AND APPEALS Rules of Practice for Appeals From Women-Owned Small...

A Compressive Superresolution Display

KAUST Repository

Heide, Felix; Gregson, James; Wetzstein, Gordon; Raskar, Ramesh; Heidrich, Wolfgang

2014-01-01

In this paper, we introduce a new compressive display architecture for superresolution image presentation that exploits co-design of the optical device configuration and compressive computation. Our display allows for superresolution, HDR, or glasses-free 3D presentation.

A Compressive Superresolution Display

KAUST Repository

Heide, Felix

2014-06-22

In this paper, we introduce a new compressive display architecture for superresolution image presentation that exploits co-design of the optical device configuration and compressive computation. Our display allows for superresolution, HDR, or glasses-free 3D presentation.

R-134a (1,1,1,2-Tetrafluoroethane) Inhalation Induced Reactive Airways Dysfunction Syndrome.

Science.gov (United States)

Doshi, Viral; Kham, Nang; Kulkarni, Shreedhar; Kapitan, Kent; Henkle, Joseph; White, Peter

2016-01-01

R-134a (1,1,1,2-tetrafluoroethane) is widely used as a refrigerant and as an aerosol propellant. Inhalation of R-134a can lead to asphyxia, transient confusion, and cardiac arrhythmias. We report a case of reactive airways dysfunction syndrome secondary to R-134a inhalation. A 60-year-old nonsmoking man without a history of lung disease was exposed to an air conditioner refrigerant spill while performing repairs beneath a school bus. Afterward, he experienced worsening shortness of breath with minimal exertion, a productive cough, and wheezing. He was also hypoxic. He was admitted to the hospital for further evaluation. Spirometry showed airflow obstruction with an FEV1 1.97 L (45% predicted). His respiratory status improved with bronchodilators and oral steroids. A repeat spirometry 2 weeks later showed improvement with an FEV1 2.5 L (60% predicted). Six months after the incident, his symptoms had improved, but he was still having shortness of breath on exertion and occasional cough.

Activity standardization of 134Cs and 137Cs

International Nuclear Information System (INIS)

Sochorová, Jana; Auerbach, Pavel

2014-01-01

The paper presents the results from a primary standardization of 137 Cs using two independent methods – efficiency tracing using PC-NaI coincidence and the TDCR method. The nuclides 60 Co and 134 Cs were used as the tracers. Primary standardization of the 134 Cs is also discussed. The efficiency extrapolation was carried out by measuring samples of varying mass and using the wet extrapolation method. The results obtained are in good agreement; the differences did not exceed 0.5%. The advantages, pitfalls and also possibilities for improvement of the procedures are discussed

42 CFR 410.134 - Provider qualifications.

Science.gov (United States)

2010-10-01

... after December 22, 2000: (a) Holds a bachelor's or higher degree granted by a regionally accredited college or university in the United States (or an equivalent foreign degree) with completion of the... PROGRAM SUPPLEMENTARY MEDICAL INSURANCE (SMI) BENEFITS Medical Nutrition Therapy § 410.134 Provider...

{sup 134}Cs in heather seed plants grown with and without mycorrhiza

Energy Technology Data Exchange (ETDEWEB)

Strandberg, M. [Risoe National Laboratory, DK-4000 Roskilde (Denmark); Johansson, M. [Department of Mycology, Botanical Institute, University of Copenhagen, Oester Farimagsgade 2D, DK-1353 Copenhagen K. (Denmark)

1988-08-01

Experiments were carried out to determine differences between mycorrhized and non-mycorrhized seed plants of heather, Calluna vulgaris(L)Hull, as regards the uptake of {sup 134}Cs. In most treatments heather with mycorrhiza had a significantly higher transfer of {sup 134}Cs to the shoots than heather without mycorrhiza. As an average the concentration of {sup 134}Cs was 18% higher in the mycorrhized plants than in the non-mycorrhized. Application of 10 kg K/ha reduced the concentration of {sup 134}Cs in shoots of heather by 49% as an average. Because of improved growth in the potassium fertilized pots the reduction viewed on the basis of the area was only 33%. Nitrogen application does not significantly influence the concentration of {sup 134}Cs in shoots of heather regardless of mycorrhizal status. (Copyright (c) 1988 Elsevier Science B.V., Amsterdam. All rights reserved.)

Release and attenuation of fluorocarbons in landfills

DEFF Research Database (Denmark)

Kjeldsen, Peter; Scheutz, Charlotte

2003-01-01

Several halocarbons with very high global warming and ozone depleting potentials have been used as blowing agent for insulation foam in refrigerators and freezers. Many appliances are shredded after the end of their useful life. Release experiments carried out in the laboratory on insulation foam...... blown with CFC-11, HCFC-141b, HFC- 134a, and HFC-245fa revealed that most of the blowing agent is not released to the atmosphere during a six-week period following the shredding process. The fraction which is released in the six-week period is highly dependent on how fine the foam is shredded....... The residual blowing agent remaining after the six-week period may be very slowly released if the integrity of the foam particles with respect to diffusional properties is kept after disposal of the foam waste in landfills. Laboratory experiments simulating attenuation processes in the landfilled waste...

Preservation of renal blood flow by the antioxidant EUK-134 in LPS-treated pigs.

Science.gov (United States)

Magder, Sheldon; Parthenis, Dimitrios G; Ghouleh, Imad Al

2015-03-25

Sepsis is associated with an increase in reactive oxygen species (ROS), however, the precise role of ROS in the septic process remains unknown. We hypothesized that treatment with EUK-134 (manganese-3-methoxy N,N'-bis(salicyclidene)ethylene-diamine chloride), a compound with superoxide dismutase and catalase activity, attenuates the vascular manifestations of sepsis in vivo. Pigs were instrumented to measure cardiac output and blood flow in renal, superior mesenteric and femoral arteries, and portal vein. Animals were treated with saline (control), lipopolysaccharide (LPS; 10 µg·kg-1·h-1), EUK-134, or EUK-134 plus LPS. Results show that an LPS-induced increase in pulmonary artery pressure (PAP) as well as a trend towards lower blood pressure (BP) were both attenuated by EUK-134. Renal blood flow decreased with LPS whereas superior mesenteric, portal and femoral flows did not change. Importantly, EUK-134 decreased the LPS-induced fall in renal blood flow and this was associated with a corresponding decrease in LPS-induced protein nitrotyrosinylation in the kidney. PO2, pH, base excess and systemic vascular resistance fell with LPS and were unaltered by EUK-134. EUK-134 also had no effect on LPS-associated increase in CO. Interestingly, EUK-134 alone resulted in higher CO, BP, PAP, mean circulatory filling pressure, and portal flow than controls. Taken together, these data support a protective role for EUK-134 in the renal circulation in sepsis.

Mining and global environmental challenges

Energy Technology Data Exchange (ETDEWEB)

Greeff, J C; Bailey-McEwan, M [Chamber of Mines of South Africa, Johannesburg (South Africa)

1992-04-01

At least half of South Africa's gold production is presently dependent on CFC11 an CFC12 as refrigerants in water chilling machines used in cooling the underground workings. The South African Government will ratify the revised Montreal Protocol on substances that deplete the ozone layer which will mean CFCs will have to be phased out probably by 1997. HFC134 or HFC22 are possible replacements for CFC but present costs of converting machines are high. The article goes on to discuss the contribution of CFCs and CO{sub 2} to global warming and model simulations and predictions of climate change. Likely effects of growing concern about global warming on the coal mining industry are the possible limitations on the use of coal and the increased need for clean coal technology. 12 refs., 5 figs., 3 tabs.

A novel Carnot-based cycle for ocean thermal energy conversion

International Nuclear Information System (INIS)

Semmari, Hamza; Stitou, Driss; Mauran, Sylvain

2012-01-01

A thermodynamic engine cycle can be implemented by exploiting the temperature difference existing between the warm surface seawater and cold deep seawater. It employs a working fluid that evaporates by warm seawater, produces work in an expander device, such as a gas turbine and finally condenses by cold deep seawater. A new Carnot-based cycle for OTEC applications, called CAPILI cycle is presented. In this new engine cycle, work is produced by the movement of an inert liquid through a hydraulic turbine. This inert liquid characterized by a very low saturation pressure and immiscibility with the working fluid, acts as a liquid piston that moves alternately between two insulated cylinders. The insulated cylinders are connected alternately to an evaporator and a condenser, each of them operates at different pressure and temperature levels. A performance study which consists in a steady state energy balance is realised first to select the most suitable working fluid for this specific application. It was found that the best fluid is the HFC refrigerant R134a. A dynamic modelling based on the concept of equivalent Gibbs system is carried out to appreciate the dynamic behaviour and the performances of this new thermal conversion process. -- Highlights: ► A novel Carnot-based cycle operating with a liquid piston is investigated for OTEC application. ► The most suitable working fluid giving the best performances is found to be the HFC R134a. ► The performances of this new thermal process are evaluated using a dynamic modelling. ► A thermal efficiency of 1.9% can be obtained by exploiting seawater temperature difference of 20 °C. ► A net cycle efficiency of 1.2% is achieved considering a net to gross power production ratio of 61%.

DNABIT Compress – Genome compression algorithm

OpenAIRE

Rajarajeswari, Pothuraju; Apparao, Allam

2011-01-01

Data compression is concerned with how information is organized in data. Efficient storage means removal of redundancy from the data being stored in the DNA molecule. Data compression algorithms remove redundancy and are used to understand biologically important molecules. We present a compression algorithm, “DNABIT Compress” for DNA sequences based on a novel algorithm of assigning binary bits for smaller segments of DNA bases to compress both repetitive and non repetitive DNA sequence. Our ...

An experimental comparison between forced convection burn-out in freon 12 flowing vertically upwards through uniformly and non-uniformly heated round tubes

International Nuclear Information System (INIS)

Stevens, G.F.; Elliott, D.F.; Wood, R.W.

1965-05-01

Some correlations of forced convection burn-out data are based on the approximate linearity of the relationship between burn-out heat flux and the channel-averaged quality at the burn-out point. These correlations perform satisfactorily on data obtained from uniformly heated configurations. Therefore the further inference is sometimes made that the burn-out heat flux is uniquely related to the quality, and that the burn-out in non-uniformly heated configurations can be calculated from measurements made with uniform heating. This report presents burn-out data for Freon 12 flowing vertically upwards through both uniformly and non-uniformly heated round tubes. This data shows that the quality at burn-out does depend on the heat flux profile, and that the inference mentioned above is not justified. (author)

Intermittent Administration of Parathyroid Hormone [1-34] Prevents Particle-Induced Periprosthetic Osteolysis in a Rat Model.

Directory of Open Access Journals (Sweden)

Fanggang Bi

Full Text Available We examined whether intermittent administration of parathyroid hormone [1-34] (PTH[1-34]; 60 μg/kg/day can prevent the negative effects of titanium (Ti particles on implant fixation and periprosthetic osteolysis in a rat model. Eighteen adult male rats (12 weeks old, bones still growing received intramedullary Ti implants in their bilateral femurs; 6 rats from the blank group received vehicle injections, and 12 rats from the control group and PTH treatment group received Ti particle injections at the time of operation and intra-articular injections 2 and 4 weeks postoperatively. Six of the rats that received Ti particles from the PTH group also received PTH[1-34] treatment. Six weeks postoperatively, all specimens were collected for assessment by X-ray, micro-CT, biomechanical, scanning electron microscopy (SEM, and dynamic histomorphometry. A lower BMD, BV/TV, Tb.N, maximal fixation strength, and mineral apposition rate were observed in the control group compared to the blank group, demonstrating that a periprosthetic osteolysis model had been successfully established. Administration of PTH[1-34] significantly increased the bone mineral density of the distal femur, BV/TV, Tb.N, Tb.Th, Tb.Sp, Con.D, SMI, and maximal fixation strength in the PTH group compared to that in the control group. SEM revealed higher bone-implant contact, thicker lamellar bone, and larger trabecular bone area in the PTH group than in the control group. A higher mineral apposition rate was observed in the PTH group compared to both the blank and control groups. These findings imply that intermittent administration of PTH[1-34] prevents periprosthetic osteolysis by promoting bone formation. The effects of PTH[1-34] were evaluated at a suprapharmacological dosage to the human equivalent in rats; therefore, additional studies are required to demonstrate its therapeutic potential in periprosthetic osteolysis.

Surface Tension and p−ρ−T Data for 1,1,1,3,3-Pentafluorobutane (HFC-365mfc) and 1,1,1,2,2,3,3-Heptafluoro-3-methoxy-propane (HFE-347mcc)

Czech Academy of Sciences Publication Activity Database

Klomfar, Jaroslav; Součková, Monika; Pátek, Jaroslav

2013-01-01

Roč. 58, č. 8 (2013), s. 2316-2325 ISSN 0021-9568 R&D Projects: GA ČR GA101/09/0010 Institutional support: RVO:61388998 Keywords : surface tension * density * HFC-365mfc * HFE-347mcc Subject RIV: BJ - Thermodynamics Impact factor: 2.045, year: 2013

13 CFR 134.407 - Evidence beyond the record and discovery.

Science.gov (United States)

2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Evidence beyond the record and discovery. 134.407 Section 134.407 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION RULES OF..., the Administrative Law Judge may not admit evidence beyond the written administrative record nor...

The accumulation of 134Cs in heart and skeletal muscle of healthy and dystrophic hamsters

International Nuclear Information System (INIS)

Szentkuti, L.; Breitrueck, H.; Giese, W.

1976-01-01

he accumulation of cesium-134 in heart and skeletal muscle of healthy and dystrophic hamsters was compared. It was lower in dystrophic hamsters than in normal ones after only a single dose of cesium-134. The 134 Cs-concentrations of heart and 'red' skeletal muscle were different between normal and dystrophic hamsters. When the isotope had equilibrated in the animals differences in 134 Cs-accumulation in muscle tissue between normal and dystrophic hamsters were even more obvious. The faster elimination of cesium-134 from the body as affected by muscular dystrophy was due to a reduction of 134 Cs-accumulation in muscle tissue. The reduced ability of damaged muscles to accumulate Cs-ions offers the possibility to use Cs-isotopes in diagnosis of skeletal muscle dystrophy. (author)

19 CFR 122.134 - When airline does not have in-bond liquor storeroom.

Science.gov (United States)

2010-04-01

... 19 Customs Duties 1 2010-04-01 2010-04-01 false When airline does not have in-bond liquor storeroom. 122.134 Section 122.134 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY AIR COMMERCE REGULATIONS Aircraft Liquor Kits § 122.134 When airline does not have in-bond liquor storeroom. (a...

Evaluation of a new image compression technique

International Nuclear Information System (INIS)

Algra, P.R.; Kroon, H.M.; Noordveld, R.B.; DeValk, J.P.J.; Seeley, G.W.; Westerink, P.H.

1988-01-01

The authors present the evaluation of a new image compression technique, subband coding using vector quantization, on 44 CT examinations of the upper abdomen. Three independent radiologists reviewed the original images and compressed versions. The compression ratios used were 16:1 and 20:1. Receiver operating characteristic analysis showed no difference in the diagnostic contents between originals and their compressed versions. Subjective visibility of anatomic structures was equal. Except for a few 20:1 compressed images, the observers could not distinguish compressed versions from original images. They conclude that subband coding using vector quantization is a valuable method for data compression in CT scans of the abdomen

Microscopic structure of liquid 1-1-1-2-tetrafluoroethane (R134a) from Monte Carlo simulation.

Science.gov (United States)

Do, Hainam; Wheatley, Richard J; Hirst, Jonathan D

2010-10-28

1-1-1-2-tetrafluoroethane (R134a) is one of the most commonly used refrigerants. Its thermophysical properties are important for evaluating the performance of refrigeration cycles. These can be obtained via computer simulation, with an insight into the microscopic structure of the liquid, which is not accessible to experiment. In this paper, vapour-liquid equilibrium properties of R134a and its liquid microscopic structure are investigated using coupled-decoupled configurational-bias Monte Carlo simulation in the Gibbs ensemble, with a recent potential [J. Phys. Chem. B 2009, 113, 178]. We find that the simulations agree well with the experimental data, except at the vicinity of the critical region. Liquid R134a packs like liquid argon, with a coordination number in the first solvation shell of 12 at 260 K. The nearest neighbours prefer to be localized in three different spaces around the central molecule, in such a manner that the dipole moments are in a parallel alignment. Analysis of the pair interaction energy shows clear association of R134a molecules, but no evidence for C-HF type hydrogen bonding is found. The above findings should be of relevance to a broad range of fluoroalkanes.

27 CFR 17.134 - Determination of unfitness for beverage purposes.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Determination of unfitness for beverage purposes. 17.134 Section 17.134 Alcohol, Tobacco Products and Firearms ALCOHOL AND... an alcoholic concentration of 15% and tasted. Sale or use for beverage purposes is indicative of...

An investigation of critical heat fluxes in vertical tubes internally cooled by Freon-12. Part I - Critical heat flux experiments with axially uniform and non-uniform heating and comparisons of data with selected correlations

International Nuclear Information System (INIS)

Green, W.J.; Stevens, J.R.

1981-08-01

Experiments have been performed using vertical heated tubes, cooled internally by Freon-12, to determine critical heat fluxes (CHFs) for both a uniformly heated section and an exit region with a separately controlled power supply. Heated lengths of the main separately were 2870 mm (8.48 and 16.76 mm tube bores) and 3700 mm (for 21.34 mm tube bore); heated length of the exit section was 230 mm. Coolant pressures, exit qualities and mass fluxes were in the range 0.9 to 1.3 MPa, 0.19 to 0.86, and 380 to 2800 kg m -2 s -1 , respectively. The data have been compared with published empirical correlations specifically formulated to predict CHFs in Freon-cooled, vertical tubes; relevant published CHF data have also been compared with these correlations. These comparisons show that, even over the ranges of conditions for which the correlations were developed, predicted values are only accurate to within +-20 per cent. Moreover, as mass fluxes increase above 3500 kg m -2 s -1 , the modified Groeneveld correlation becomes increasingly inadequate, and the Bertoletti and modified Bertoletti correlations under-predict CHF values by increasing amounts. At mass fluxes below 750 kg m -2 s -1 the Bertoletti correlations exhibit increasing inaccuracy with a decrease in mass flux. For non-uniform heating, the correlations are at variance with the experimental data

Elucidation of the critical epitope of an anti-EGFR monoclonal antibody EMab-134.

Science.gov (United States)

Kaneko, Mika K; Yamada, Shinji; Itai, Shunsuke; Chang, Yao-Wen; Nakamura, Takuro; Yanaka, Miyuki; Kato, Yukinari

2018-07-01

The epidermal growth factor receptor (EGFR) is a type-1 transmembrane receptor tyrosine kinase, which activates the downstream signaling cascades in many tumors, such as oral and lung cancers. We previously developed EMab-134, a novel anti-EGFR monoclonal antibody (mAb), which reacts with endogenous EGFR-expressing cancer cell lines and normal cells independent of glycosylation in Western blotting, flow cytometry, and immunohistochemical analysis. EMab-134 showed very high sensitivity (94.7%) to oral squamous cell carcinomas in immunohistochemical analysis. In this study, we performed enzyme-linked immunosorbent assay (ELISA), flow cytometry, and immunohistochemical analysis to determine the epitope of EMab-134. A blocking peptide (375-394 amino acids of EGFR) neutralized the EMab-134 reaction against oral cancer cells in flow cytometry and immunohistochemistry. The minimum epitope of EMab-134 was found to be the 377- RGDSFTHTPP -386 sequence. Our findings can be applied for the production of more functional anti-EGFR mAbs that in turn can be used for antitumor treatments.

10 CFR 60.134 - Design of seals for shafts and boreholes.

Science.gov (United States)

2010-01-01

... 10 Energy 2 2010-01-01 2010-01-01 false Design of seals for shafts and boreholes. 60.134 Section....134 Design of seals for shafts and boreholes. (a) General design criterion. Seals for shafts and... closure. (b) Selection of materials and placement methods. Materials and placement methods for seals shall...

13 CFR 134.708 - What is the standard of review?

Science.gov (United States)

2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false What is the standard of review? 134.708 Section 134.708 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION RULES OF PROCEDURE GOVERNING CASES BEFORE THE OFFICE OF HEARINGS AND APPEALS Rules of Practice for Appeals From Women...

Effect of Deinococcus radiodurans on uptake of 134Cs by Brassica oleracea

International Nuclear Information System (INIS)

Zhu Cong; Guo Jiangfeng

2008-01-01

Deinococcus radiodurans was inoculated into the soil which was spiked with 134 Cs to investigate its effect on chemical speciation of 134 Cs. The relationship between chemical speciation of 134 Cs and its absorbtion capacity by cabbage (Brassica oleracea) in the presence of D. radiodurans was also investigated. The results showed that an increase of 28.64%-38.17 % in content of 134 Cs in residual phase was observed with presence of D. radiodurans in comparison with the aseptic control. The amounts of radiocesium uptaken by cabbage were about 12100Bq/g under aseptic conditions, however, which were about 8500Bq/g with the presence of D. radiodurans. The proportion of 134 Cs taken up by cabbage decreased about 29% in comparison with the aseptic control. The chemical speciation could be influenced by D. radiodurans so that its uptake by plants could be reduced. (authors)

Test Report #33: Compressor Calorimeter Test of R-410A Alternative: R-32/R-134a Mixture Using a Scroll Compressor

Energy Technology Data Exchange (ETDEWEB)

Shrestha, Som [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sharma, Vishaldeep [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Abdelaziz, Omar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2014-02-18

This report investigates the tested performance of lower - GWP candidate refrigerant, 94.07 wt% R - 32 + 5.93 wt % R - 134 a mixture (hereafter referred to as R - 32/134a), as an alternative to baseline refrigerant R - 410 A using a 36,000 Btu/hr compressor calorimeter located at the Heat Exchanger Advanced Testing Facility at Oak Ridge National Laboratory . These tests were conducted during May and August 2013. R - 410A is a near - azeotropic blend of R - 32 and R - 125 with 0.5/0.5 mass fraction and has a GWP 100 of 2100. R - 32 and R - 134a are pure refrigerants and have GWP 100 of 716 and 1370 1, respectively. Based on the GWP 100 values of pure refrigerants and their mass fraction in the blend, GWP 100 of R - 32/134a, which is under development by National Refrigerant, is 755. This report compares various performance parameters, such as cooling capacity, compressor power, refrigerant mass flow rate, EER, isentropic efficiency and discharge temperature of the alternative refrigerant to that of R - 410 A.

33 CFR 162.134 - Connecting waters from Lake Huron to Lake Erie; traffic rules.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Connecting waters from Lake Huron to Lake Erie; traffic rules. 162.134 Section 162.134 Navigation and Navigable Waters COAST GUARD... REGULATIONS § 162.134 Connecting waters from Lake Huron to Lake Erie; traffic rules. (a) Detroit River. The...

Vapor-liquid critical surface of ternary difluoromethane + pentafluoroethane + 1,1,1,2-tetrafluoroethane (R-32/125/134a) mixtures

Energy Technology Data Exchange (ETDEWEB)

Higashi, Y.

1999-09-01

The plane of vapor-liquid criticality for ternary refrigerant mixtures of difluoromethane (R-32) + pentafluoroethane (R-125) + 1,1,1,2-tetrafluoroethane (R-134a) was determined from data on the vapor-liquid coexistence curve near the mixture critical points. The composition (mass percentage) of the mixtures studied were 23% R-32 + 25% R-125 + 52% R-134a (R-407C). 25% R-32 + 15% R-125 + 60% R-134a (R-407E), and 20% R-32 + 40% R-125 + 40% R-134a (R-407A). The critical temperature of each mixture was determined by observation of the disappearance of the meniscus. The critical density of each mixture was determined on the basis of meniscus disappearance level and the intensity of the critical opalescence. The uncertainties of the temperature, density, and composition measurements are estimated as {+-}10mK, {+-}5kg{center_dot}m{sup {minus}3}, and {+-}0.05%, respectively. In addition, predictive methods for the critical parameters of R-32/125/134a mixtures are discussed.

Comparative data compression techniques and multi-compression results

International Nuclear Information System (INIS)

Hasan, M R; Ibrahimy, M I; Motakabber, S M A; Ferdaus, M M; Khan, M N H

2013-01-01

Data compression is very necessary in business data processing, because of the cost savings that it offers and the large volume of data manipulated in many business applications. It is a method or system for transmitting a digital image (i.e., an array of pixels) from a digital data source to a digital data receiver. More the size of the data be smaller, it provides better transmission speed and saves time. In this communication, we always want to transmit data efficiently and noise freely. This paper will provide some compression techniques for lossless text type data compression and comparative result of multiple and single compression, that will help to find out better compression output and to develop compression algorithms

A statistical–mechanical view on source coding: physical compression and data compression

International Nuclear Information System (INIS)

Merhav, Neri

2011-01-01

We draw a certain analogy between the classical information-theoretic problem of lossy data compression (source coding) of memoryless information sources and the statistical–mechanical behavior of a certain model of a chain of connected particles (e.g. a polymer) that is subjected to a contracting force. The free energy difference pertaining to such a contraction turns out to be proportional to the rate-distortion function in the analogous data compression model, and the contracting force is proportional to the derivative of this function. Beyond the fact that this analogy may be interesting in its own right, it may provide a physical perspective on the behavior of optimum schemes for lossy data compression (and perhaps also an information-theoretic perspective on certain physical system models). Moreover, it triggers the derivation of lossy compression performance for systems with memory, using analysis tools and insights from statistical mechanics

Studies in boiling heat transfer in two phase flow through tube arrays: nucleate boiling heat transfer coefficient and maximum heat flux as a function of velocity and quality of Freon-113

International Nuclear Information System (INIS)

Rahmani, R.

1983-01-01

The nucleate boiling heat-transfer coefficient and the maximum heat flux were studied experimentally as functions of velocity, quality and heater diameter for single-phase flow, and two-phase flow of Freon-113 (trichlorotrifluorethane). Results show: (1) peak heat flux: over 300 measured peak heat flux data from two 0.875-in. and four 0.625-in.-diameter heaters indicated that: (a) for pool boiling, single-phase and two-phase forced convection boiling the only parameter (among hysteresis, rate of power increase, aging, presence and proximity of unheated rods) that has a statistically significant effect on the peak heat flux is the velocity. (b) In the velocity range (0 0 position or the point of impact of the incident fluid) and the top (180 0 position) of the test element, respectively

Sulfur Bridged Multidentate Ligands Based on (Bipyridyl-(Bi-1,3,4-Thiadiazolyl Conjugates

Directory of Open Access Journals (Sweden)

M. Teresa Clasadonte

2003-03-01

Full Text Available The synthesis of a series of mixed (bipyridyl/(bi1,3,4-thiadiazolyl ligands, derived from the condensation of 2-mercapto-5-methylthio-1,3,4-thiadiazole or 5-mercapto-5'-methylthio-2,2'-bi-1,3,4-thiadiazole with 2,6-bis(chloromethylpyridine or 6,6’-bis(chloromethyl-2,2’-bipyridine (compounds L1–L4, and of 2,5-dimercapto-1,3,4-thiadiazole or 5,5'-dimercapto-2,2'-di-1,3,4-thiadiazole with picolyl chloride hydrochloride or 6-chloromethyl-6'-methyl-2,2'-bipyridine (compounds L5–L8 in the presence of triethylamine is described. All new compounds have been characterized by FAB (+ spectrometry and NMR spectroscopy. 13C-NMR spectra are crucial to firmly establish the thiol structure of the title ligands.

Indirect phase transition of TiC, ZrC, and HfC crystal structures

Energy Technology Data Exchange (ETDEWEB)

Abavare, Eric K.K.; Dodoo, Samuel N.A. [Department of Physics, Kwame Nkrumah University of Science and Technology, Kumasi (Ghana); Uchida, Kazuyuki; Oshiyama, Atsushi [Department of Applied Physics, The University of Tokyo, Hongo, Tokyo (Japan); Nkurumah-Buandoh, George K.; Yaya, Abu [Department of Physics, University of Ghana, Legon (Ghana)

2016-06-15

We have performed first-principles calculations to analyze the electronic structures, static, and dynamical structural stabilities of the pressure-induced phase transformation of refractory compounds (transition-metal carbides) from NaCl-type (B1) to CsCl-type (B2) via zinc-blende phase using the plane-wave pseudopotential approach in the framework of the generalized gradient approximation (GGA) for the exchange and correlation functional. The ground-state properties, equilibrium lattice constant, bulk moduli, and band structures are determined for the stoichiometry of the compounds and compared with known experimental and theoretical values. We find that the phase-transition pressure for the indirect phase transition from B1→B2 via zinc-blende structure is about 17-fold for TiC, 12-fold for both ZrC and HfC, respectively, when compared with the direct phase transition. Calculated phonon instability exists for the CsCl-B2 phase, which can prevent the structures from forming and contrary to the zinc-blende and the NaCl-B1 phases. The band dispersion and electronic density of states for B1 and B2 crystal phases were explored and found to indicate metallic character in contrast with the zinc-blende phase, which has a pseudogap opening in the bandgap region suggesting a semiconducting property and also a frequency gap in the phonon spectrum. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Elucidation of the critical epitope of an anti-EGFR monoclonal antibody EMab-134

Directory of Open Access Journals (Sweden)

Mika K. Kaneko

2018-07-01

Full Text Available The epidermal growth factor receptor (EGFR is a type-1 transmembrane receptor tyrosine kinase, which activates the downstream signaling cascades in many tumors, such as oral and lung cancers. We previously developed EMab-134, a novel anti-EGFR monoclonal antibody (mAb, which reacts with endogenous EGFR-expressing cancer cell lines and normal cells independent of glycosylation in Western blotting, flow cytometry, and immunohistochemical analysis. EMab-134 showed very high sensitivity (94.7% to oral squamous cell carcinomas in immunohistochemical analysis. In this study, we performed enzyme-linked immunosorbent assay (ELISA, flow cytometry, and immunohistochemical analysis to determine the epitope of EMab-134. A blocking peptide (375–394 amino acids of EGFR neutralized the EMab-134 reaction against oral cancer cells in flow cytometry and immunohistochemistry. The minimum epitope of EMab-134 was found to be the 377-RGDSFTHTPP−386 sequence. Our findings can be applied for the production of more functional anti-EGFR mAbs that in turn can be used for antitumor treatments.

Transfer factors of 134Cs for olive and orange trees grown on different soils

International Nuclear Information System (INIS)

Skarlou, V.; Nobeli, C.; Anoussis, J.; Haidouti, C.; Papanicolaou, E.

1999-01-01

Transfer factors (TF) of 134 Cs to olive and citrus trees grown on two different soils, were determined for a 3-year greenhouse experiment. Two-year-old trees were transplanted with their entire rootball into large pots containing the contaminated soil (110 kg pot -1 ). The soil was transferred to each pot in layers on the top of which 134 Cs as CsCl was dripped (18.5 MBq pot -1 ). For both evergreen trees, soil type significantly influenced radiocaesium transfer. 134 Cs concentration was lower for the calcareous-heavy soil than for the acid-light soil. Transfer factors of orange trees were higher than those of olive trees in the acid-light soil. Although a significant amount of 134 Cs was measured in olives grown on the acid-light soil, no 134 Cs was detected in the unprocessed olive oil when an oil fraction (5% f.w.) was extracted. On the contrary the edible part of the oranges showed the highest 134 Cs concentration of all plant parts. The relationship between 134 Cs uptake and potassium content in the different plant compartments was also studied when selected trees were cut down. The potassium concentration in the plants was not significantly different between the trees growing in the two types of soil in spite of the big differences in the 134 Cs uptake in the two soils. TF values and potassium content in the different plant compartments of each tree were highly correlated. For both crops transfer factors as well as potassium content were the highest in the developing plant parts (new leaves and branches, flowers). The transfer factors of 134 Cs for the studied trees are in the same order of magnitude as the values of annual crops grown under similar conditions. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Munc13-4 Is a Rab11-binding Protein That Regulates Rab11-positive Vesicle Trafficking and Docking at the Plasma Membrane.

Science.gov (United States)

Johnson, Jennifer L; He, Jing; Ramadass, Mahalakshmi; Pestonjamasp, Kersi; Kiosses, William B; Zhang, Jinzhong; Catz, Sergio D

2016-02-12

The small GTPase Rab11 and its effectors control trafficking of recycling endosomes, receptor replenishment and the up-regulation of adhesion and adaptor molecules at the plasma membrane. Despite recent advances in the understanding of Rab11-regulated mechanisms, the final steps mediating docking and fusion of Rab11-positive vesicles at the plasma membrane are not fully understood. Munc13-4 is a docking factor proposed to regulate fusion through interactions with SNAREs. In hematopoietic cells, including neutrophils, Munc13-4 regulates exocytosis in a Rab27a-dependent manner, but its possible regulation of other GTPases has not been explored in detail. Here, we show that Munc13-4 binds to Rab11 and regulates the trafficking of Rab11-containing vesicles. Using a novel Time-resolved Fluorescence Resonance Energy Transfer (TR-FRET) assay, we demonstrate that Munc13-4 binds to Rab11a but not to dominant negative Rab11a. Immunoprecipitation analysis confirmed the specificity of the interaction between Munc13-4 and Rab11, and super-resolution microscopy studies support the interaction of endogenous Munc13-4 with Rab11 at the single molecule level in neutrophils. Vesicular dynamic analysis shows the common spatio-temporal distribution of Munc13-4 and Rab11, while expression of a calcium binding-deficient mutant of Munc13-4 significantly affected Rab11 trafficking. Munc13-4-deficient neutrophils showed normal endocytosis, but the trafficking, up-regulation, and retention of Rab11-positive vesicles at the plasma membrane was significantly impaired. This correlated with deficient NADPH oxidase activation at the plasma membrane in response to Rab11 interference. Our data demonstrate that Munc13-4 is a Rab11-binding partner that regulates the final steps of Rab11-positive vesicle docking at the plasma membrane. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Induction of a shorter compression phase is correlated with a deeper chest compression during metronome-guided cardiopulmonary resuscitation: a manikin study.

Science.gov (United States)

Chung, Tae Nyoung; Bae, Jinkun; Kim, Eui Chung; Cho, Yun Kyung; You, Je Sung; Choi, Sung Wook; Kim, Ok Jun

2013-07-01

Recent studies have shown that there may be an interaction between duty cycle and other factors related to the quality of chest compression. Duty cycle represents the fraction of compression phase. We aimed to investigate the effect of shorter compression phase on average chest compression depth during metronome-guided cardiopulmonary resuscitation. Senior medical students performed 12 sets of chest compressions following the guiding sounds, with three down-stroke patterns (normal, fast and very fast) and four rates (80, 100, 120 and 140 compressions/min) in random sequence. Repeated-measures analysis of variance was used to compare the average chest compression depth and duty cycle among the trials. The average chest compression depth increased and the duty cycle decreased in a linear fashion as the down-stroke pattern shifted from normal to very fast (pmetronome-guided cardiopulmonary resuscitation.

Peyton's 4-Steps-Approach in comparison: Medium-term effects on learning external chest compression - a pilot study.

Science.gov (United States)

Münster, Tobias; Stosch, Christoph; Hindrichs, Nina; Franklin, Jeremy; Matthes, Jan

2016-01-01

The external chest compression is a very important skill required to maintain a minimum of circulation during cardiac arrest until further medical procedures can be taken. Peyton's 4-Steps-Approach is one method of skill training, the four steps being: Demonstration, Deconstruction, Comprehension and Execution. Based on CPR skill training, this method is widely, allegedly predominantly used, although there are insufficient studies on Peyton's 4-Steps-Approach for skill training in CPR in comparison with other methods of skill training. In our study, we compared the medium- term effects on learning external chest compression with a CPR training device in three different groups: PEY (Peyton's 4-Steps-Approach), PMOD (Peyton's 4-Steps-Approach without Step 3) and STDM, the standard model, according to the widely spread method "see one, do one" (this is equal to Peyton's step 1 and 3). This prospective and randomised pilot study took place during the summer semester of 2009 at the SkillsLab and Simulation Centre of the University of Cologne (Kölner interprofessionelles Skills Lab und Simulationszentrum - KISS). The subjects were medical students (2(nd) and 3(rd) semester). They volunteered for the study and were randomised in three parallel groups, each receiving one of the teaching methods mentioned above. One week and 5/6 months after the intervention, an objective, structured single assessment was taken. Compression rate, compression depth, correct compressions, and the sum of correct checklist items were recorded. Additionally, we compared cumulative percentages between the groups based on the correct implementation of the resuscitation guidelines during that time. The examined sample consisted of 134 subjects (68% female; age 22±4; PEY: n=62; PMOD: n=31; STDM: n=41). There was no difference between the groups concerning age, gender, pre-existing experience in CPR or time of last CPR course. The only significant difference between the groups was the mean

Efficient Lossy Compression for Compressive Sensing Acquisition of Images in Compressive Sensing Imaging Systems

Directory of Open Access Journals (Sweden)

Xiangwei Li

2014-12-01

Full Text Available Compressive Sensing Imaging (CSI is a new framework for image acquisition, which enables the simultaneous acquisition and compression of a scene. Since the characteristics of Compressive Sensing (CS acquisition are very different from traditional image acquisition, the general image compression solution may not work well. In this paper, we propose an efficient lossy compression solution for CS acquisition of images by considering the distinctive features of the CSI. First, we design an adaptive compressive sensing acquisition method for images according to the sampling rate, which could achieve better CS reconstruction quality for the acquired image. Second, we develop a universal quantization for the obtained CS measurements from CS acquisition without knowing any a priori information about the captured image. Finally, we apply these two methods in the CSI system for efficient lossy compression of CS acquisition. Simulation results demonstrate that the proposed solution improves the rate-distortion performance by 0.4~2 dB comparing with current state-of-the-art, while maintaining a low computational complexity.

Radiologic image compression -- A review

International Nuclear Information System (INIS)

Wong, S.; Huang, H.K.; Zaremba, L.; Gooden, D.

1995-01-01

The objective of radiologic image compression is to reduce the data volume of and to achieve a lot bit rate in the digital representation of radiologic images without perceived loss of image quality. However, the demand for transmission bandwidth and storage space in the digital radiology environment, especially picture archiving and communication systems (PACS) and teleradiology, and the proliferating use of various imaging modalities, such as magnetic resonance imaging, computed tomography, ultrasonography, nuclear medicine, computed radiography, and digital subtraction angiography, continue to outstrip the capabilities of existing technologies. The availability of lossy coding techniques for clinical diagnoses further implicates many complex legal and regulatory issues. This paper reviews the recent progress of lossless and lossy radiologic image compression and presents the legal challenges of using lossy compression of medical records. To do so, the authors first describe the fundamental concepts of radiologic imaging and digitization. Then, the authors examine current compression technology in the field of medical imaging and discuss important regulatory policies and legal questions facing the use of compression in this field. The authors conclude with a summary of future challenges and research directions. 170 refs

[Overexpressed miRNA-134b inhibits proliferation and invasion of CD133+ U87 glioma stem cells].

Science.gov (United States)

Liu, Yifeng; Zhang, Baochao; Wen, Changming; Wen, Gongling; Zhou, Guoping; Zhang, Jingwei; He, Haifa; Wang, Ning; Li, Wei

2017-05-01

Objective To investigate the role of microRNA-134b (miR-134b) in the tumorigenesis of glioma stem cells (GSCs) and the possible molecular mechanism. Methods Real-time quantitative PCR (qRT-PCR) was used to evalate the expression of miR-134b in CD133 + and CD133 - U87 GSCs. A lentiviral vector overexpressing miR-134b in U87 GSCs was constructed, and the effect of miR-134b overexpression on matrix metalloproteinase-2 (MMP-2), MMP-9 and MMP-12 expressions at both mRNA and protein levels were detected by qRT-PCR and Western blotting, respectively. Transwell TM assay was performed to determine the effect of miR-134b overexpression on GSCs invasion ability. Tumor xenograft models in nude mice were established to evaluate the effect of miR-134b overexpression on tumorgenesis in vivo. Results The qRT-PCR showed that, compared with CD133 - cells, miR-134b was significantly down-regulated in CD133 + cells. Cell line over-expressing miR-134b was successfully established, and miR-134b was up-regulated significantly compared with empty vector control. Overexpression of miR-134b remarkably inhibited the invasion of U87 GSCs and the expression of MMP-12. However, overexpression of miR-134b did not affect MMP-2 and MMP-9 expressions. miR-134b also suppressed U87 GSCs xenograft growth in vivo. Tumor volume in tumor xenograft model group was significantly lower than that in control group, and tumor weight decreased by 42% in the former group. Conclusion Overexpression of miR-134b inhibits the growth and invasion of CD133 + GSCs.

Selecting a general-purpose data compression algorithm

Science.gov (United States)

Mathews, Gary Jason

1995-01-01

The National Space Science Data Center's Common Data Formate (CDF) is capable of storing many types of data such as scalar data items, vectors, and multidimensional arrays of bytes, integers, or floating point values. However, regardless of the dimensionality and data type, the data break down into a sequence of bytes that can be fed into a data compression function to reduce the amount of data without losing data integrity and thus remaining fully reconstructible. Because of the diversity of data types and high performance speed requirements, a general-purpose, fast, simple data compression algorithm is required to incorporate data compression into CDF. The questions to ask are how to evaluate and compare compression algorithms, and what compression algorithm meets all requirements. The object of this paper is to address these questions and determine the most appropriate compression algorithm to use within the CDF data management package that would be applicable to other software packages with similar data compression needs.

Intercomparison of radionuclides measurements in marine cockle flesh sample IAEA-134

International Nuclear Information System (INIS)

Ballestra, S.; Gastaud, J.; Lopez, J.J.; Parsi, P.; Vas, D.

1993-08-01

The results of an intercomparison exercise on a cockle flesh sample from Irish Sea, IAEA-134, designed for the determination of artificial and natural radionuclide levels, are reported. The data from 134 laboratories representing 49 countries have been evaluated. The following are the recommended values, with confidence intervals, for 40 K, 60 Co, 137 Cs, and 2 39+240 Pu (Reference date: 1 January 1992). Information values for 90 Sr, 106 Ru, 125 Sb, 134 Cs, 154 Eu, 155 Eu, 210 Pb, 210 Po, 226 Ra, 228 Ra, 228 Th, 230 Th, 232 Th, 234 U, 235 U, 238 U, 238 Pu and 241 Am are also reported. All the following values are expressed in Bq kg -1 (dry weight). (author)

The complete multipartite genome sequence of Cupriavidus necator JMP134, a versatile pollutant degrader.

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Athanasios Lykidis

Full Text Available BACKGROUND: Cupriavidus necator JMP134 is a Gram-negative beta-proteobacterium able to grow on a variety of aromatic and chloroaromatic compounds as its sole carbon and energy source. METHODOLOGY/PRINCIPAL FINDINGS: Its genome consists of four replicons (two chromosomes and two plasmids containing a total of 6631 protein coding genes. Comparative analysis identified 1910 core genes common to the four genomes compared (C. necator JMP134, C. necator H16, C. metallidurans CH34, R. solanacearum GMI1000. Although secondary chromosomes found in the Cupriavidus, Ralstonia, and Burkholderia lineages are all derived from plasmids, analyses of the plasmid partition proteins located on those chromosomes indicate that different plasmids gave rise to the secondary chromosomes in each lineage. The C. necator JMP134 genome contains 300 genes putatively involved in the catabolism of aromatic compounds and encodes most of the central ring-cleavage pathways. This strain also shows additional metabolic capabilities towards alicyclic compounds and the potential for catabolism of almost all proteinogenic amino acids. This remarkable catabolic potential seems to be sustained by a high degree of genetic redundancy, most probably enabling this catabolically versatile bacterium with different levels of metabolic responses and alternative regulation necessary to cope with a challenging environment. From the comparison of Cupriavidus genomes, it is possible to state that a broad metabolic capability is a general trait for Cupriavidus genus, however certain specialization towards a nutritional niche (xenobiotics degradation, chemolithoautotrophy or symbiotic nitrogen fixation seems to be shaped mostly by the acquisition of "specialized" plasmids. CONCLUSIONS/SIGNIFICANCE: The availability of the complete genome sequence for C. necator JMP134 provides the groundwork for further elucidation of the mechanisms and regulation of chloroaromatic compound biodegradation.

Compression device for feeding a waste material to a reactor

Science.gov (United States)

Williams, Paul M.; Faller, Kenneth M.; Bauer, Edward J.

2001-08-21

A compression device for feeding a waste material to a reactor includes a waste material feed assembly having a hopper, a supply tube and a compression tube. Each of the supply and compression tubes includes feed-inlet and feed-outlet ends. A feed-discharge valve assembly is located between the feed-outlet end of the compression tube and the reactor. A feed auger-screw extends axially in the supply tube between the feed-inlet and feed-outlet ends thereof. A compression auger-screw extends axially in the compression tube between the feed-inlet and feed-outlet ends thereof. The compression tube is sloped downwardly towards the reactor to drain fluid from the waste material to the reactor and is oriented at generally right angle to the supply tube such that the feed-outlet end of the supply tube is adjacent to the feed-inlet end of the compression tube. A programmable logic controller is provided for controlling the rotational speed of the feed and compression auger-screws for selectively varying the compression of the waste material and for overcoming jamming conditions within either the supply tube or the compression tube.

30 CFR 75.1730 - Compressed air; general; compressed air systems.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Compressed air; general; compressed air systems... Compressed air; general; compressed air systems. (a) All pressure vessels shall be constructed, installed... Safety and Health district office. (b) Compressors and compressed-air receivers shall be equipped with...

13 CFR 134.712 - What are the limitations on new evidence?

Science.gov (United States)

2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false What are the limitations on new evidence? 134.712 Section 134.712 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION RULES OF PROCEDURE GOVERNING CASES BEFORE THE OFFICE OF HEARINGS AND APPEALS Rules of Practice for Appeals From Women...

13 CFR 134.706 - What are the service and filing requirements?

Science.gov (United States)

2010-01-01

... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false What are the service and filing requirements? 134.706 Section 134.706 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION RULES OF PROCEDURE GOVERNING CASES BEFORE THE OFFICE OF HEARINGS AND APPEALS Rules of Practice for Appeals From Women...

MicroRNA-134 as a potential plasma biomarker for the diagnosis of acute pulmonary embolism

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Liu Yi

2011-09-01

Full Text Available Abstract Background Acute pulmonary embolism (APE remains a diagnostic challenge due to a variable clinical presentation and the lack of a reliable screening tool. MicroRNAs (miRNAs regulate gene expression in a wide range of pathophysiologic processes. Circulating miRNAs are emerging biomarkers in heart failure, type 2 diabetes and other disease states; however, using plasma miRNAs as biomarkers for the diagnosis of APE is still unknown. Methods Thirty-two APE patients, 32 healthy controls, and 22 non-APE patients (reported dyspnea, chest pain, or cough were enrolled in this study. The TaqMan miRNA microarray was used to identify dysregulated miRNAs in the plasma of APE patients. The TaqMan-based miRNA quantitative real-time reverse transcription polymerase chain reactions were used to validate the dysregulated miRNAs. The receiver-operator characteristic (ROC curve analysis was conducted to evaluate the diagnostic accuracy of the miRNA identified as the candidate biomarker. Results Plasma miRNA-134 (miR-134 level was significantly higher in the APE patients than in the healthy controls or non-APE patients. The ROC curve showed that plasma miR-134 was a specific diagnostic predictor of APE with an area under the curve of 0.833 (95% confidence interval, 0.737 to 0.929; P Conclusions Our findings indicated that plasma miR-134 could be an important biomarker for the diagnosis of APE. Because of this finding, large-scale investigations are urgently needed to pave the way from basic research to clinical utilization.

A New Approach for Fingerprint Image Compression

Energy Technology Data Exchange (ETDEWEB)

Mazieres, Bertrand

1997-12-01

The FBI has been collecting fingerprint cards since 1924 and now has over 200 million of them. Digitized with 8 bits of grayscale resolution at 500 dots per inch, it means 2000 terabytes of information. Also, without any compression, transmitting a 10 Mb card over a 9600 baud connection will need 3 hours. Hence we need a compression and a compression as close to lossless as possible: all fingerprint details must be kept. A lossless compression usually do not give a better compression ratio than 2:1, which is not sufficient. Compressing these images with the JPEG standard leads to artefacts which appear even at low compression rates. Therefore the FBI has chosen in 1993 a scheme of compression based on a wavelet transform, followed by a scalar quantization and an entropy coding : the so-called WSQ. This scheme allows to achieve compression ratios of 20:1 without any perceptible loss of quality. The publication of the FBI specifies a decoder, which means that many parameters can be changed in the encoding process: the type of analysis/reconstruction filters, the way the bit allocation is made, the number of Huffman tables used for the entropy coding. The first encoder used 9/7 filters for the wavelet transform and did the bit allocation using a high-rate bit assumption. Since the transform is made into 64 subbands, quite a lot of bands receive only a few bits even at an archival quality compression rate of 0.75 bit/pixel. Thus, after a brief overview of the standard, we will discuss a new approach for the bit-allocation that seems to make more sense where theory is concerned. Then we will talk about some implementation aspects, particularly for the new entropy coder and the features that allow other applications than fingerprint image compression. Finally, we will compare the performances of the new encoder to those of the first encoder.

13 CFR 134.703 - When must a person file an appeal from an WOSB or EDWOSB protest determination?

Science.gov (United States)

2010-01-01

... APPEALS Rules of Practice for Appeals From Women-Owned Small Business Concern (WOSB) and Economically... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false When must a person file an appeal from an WOSB or EDWOSB protest determination? 134.703 Section 134.703 Business Credit and Assistance...

Analysis of South Carolina hydrogen and fuel cell workers views and opinion leadership behavior: A waiting opportunity?

Energy Technology Data Exchange (ETDEWEB)

Besley, John C. [School of Journalism and Mass Communications, University of South Carolina, Columbia, SC 29205 (United States); Baxter-Clemmons, Shannon [South Carolina Hydrogen Fuel Cell Alliance, P.O. Box 12302, Columbia, SC 29201 (United States)

2010-08-15

The current study uses quantitative survey results to explore what a near census of hydrogen and fuel cell (HFC) workers in South Carolina (n = 70) say about their HFC experiences and the degree to which these workers can be expected to act as opinion leaders for the field. In general, these workers say they are positive about the environmental, national security, and economic potential of HFC technologies. They further see HFC technologies as having small and manageable levels of risk. A number of these workers exhibit characteristics associated with both issue-specific and general opinion leadership. Issue-specific leadership and positive views about HFC technology were associated with higher levels of self-reported technology-related interpersonal discussion. The study concludes that the existence of workers with positive HFC experiences and a demonstrated interest in telling others about their experiences may represent an opportunity for those charged with promoting HFC development and adoption. Future efforts should explore how HFC workers could be effectively integrated into such efforts as a means of reaching difficult to reach audiences. (author)

Antagomirs Targeting MicroRNA-134 Increase Limk1 Levels After Experimental Seizures in Vitro and in Vivo

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Jiahang Sun

2017-09-01

Full Text Available Background: MiR-134 is enriched in dendrites of hippocampal neurons and plays crucial roles in the progress of epilepsy. The present study aims to investigate the effects of antagomirs targeting miroRNA-134 (Ant-134 on limk1 expression and the binding of miR-134 and limk1 in experimental seizure. Methods: Status epilepticus (SE rat model was established by lithium chloride-pilocarpine injection and was treated with Ant-134 by intracerebroventricular injection. Low Mg2+-exposed primary neurons were used as an in vitro model of SE. The expression of miR-134 was determined using real-time PCR. Protein expressions of limk1 and cofilin were determined by Western blotting. Luciferase reporter assay was used to examine the binding between miR-134 and limk1 3’-untranslated region. Results: The expression of miR-134 was markedly enhanced in hippocampus of the SE rats and low Mg2+-exposed neurons. Ant-134 increased the expression of limk1 and reduced the expression of cofilin in the SE hippocampus and Low Mg2+-exposed neurons. In addition, luciferase reporter assay confirmed that miR-134 bound limk1 3’-UTR. MiR-134 overexpression inhibited limk1 mRNA and protein expressions in neurons. Conclusion: Blockage of miR-134 upregulates limk1 expression and downregulated cofilin expression in hippocampus of the SE rats. This mechanism may contribute to the neuroprotective effects of Ant-134.

Decomposition of SF6-R134a effluents by RF plasma

International Nuclear Information System (INIS)

Joshi, Avinash V.

2012-01-01

The efficiency of recovery achieved by open or closed loop extraction of RPC exhaust gases is in the range of 90-95% under optimum conditions. For a large detector setup operating on one volume change per day basis, a 5% loss amounts to discharging 50 kg of R134a and 0.5 kg of SF 6 into atmosphere every day. The emissions are equivalent to create nearly 50 000 m 3 of carbon dioxide daily. The gas emissions need to be completely converted to safer compounds. The gases such as R134a and SF 6 are stable compounds. In order to decompose these, the mixture is first activated by adding of 50% oxygen and 2% argon and under typical RF plasma conditions of 13.56 MHz, 1 Torr pressure and 0.2 W/cm 2 power density. The chemical reaction takes place on the surface of a silicon electrode. The product of the reaction is mainly SiF 4 (gas), which is further hydrolyzed to form HF solution and silicon hydroxide sludge. More than 90% of the effluent gas mixture can be effectively removed by this method.

Determination of Cs-134 and Cs-137 rain water samples

International Nuclear Information System (INIS)

Lima, M.F.; Mazzilli, B.

1988-01-01

In order to setting an environmental monitoring program at IPEN, was developed a fast and simple methodology for concentration of Cs-134 and Cs-137 in rain water. This procedure consists in the precipitation of cesium and others cathions of its family (NH 4 + , K + and Rb + ) by ammonium molybdophosphate. The measures of the desintegration rates of Cs-134 and Cs-137 was done by gamma spectrometry in a Ge(Li) detector. After setting up the ideal experimental conditions, the procedure was used to analyze four samples of rain water. (author) [pt

A review on compressed pattern matching

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Surya Prakash Mishra

2016-09-01

Full Text Available Compressed pattern matching (CPM refers to the task of locating all the occurrences of a pattern (or set of patterns inside the body of compressed text. In this type of matching, pattern may or may not be compressed. CPM is very useful in handling large volume of data especially over the network. It has many applications in computational biology, where it is useful in finding similar trends in DNA sequences; intrusion detection over the networks, big data analytics etc. Various solutions have been provided by researchers where pattern is matched directly over the uncompressed text. Such solution requires lot of space and consumes lot of time when handling the big data. Various researchers have proposed the efficient solutions for compression but very few exist for pattern matching over the compressed text. Considering the future trend where data size is increasing exponentially day-by-day, CPM has become a desirable task. This paper presents a critical review on the recent techniques on the compressed pattern matching. The covered techniques includes: Word based Huffman codes, Word Based Tagged Codes; Wavelet Tree Based Indexing. We have presented a comparative analysis of all the techniques mentioned above and highlighted their advantages and disadvantages.

13 CFR 134.710 - Who can file a response to an appeal petition and when must such a response be filed?

Science.gov (United States)

2010-01-01

... APPEALS Rules of Practice for Appeals From Women-Owned Small Business Concern (WOSB) and Economically... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Who can file a response to an appeal petition and when must such a response be filed? 134.710 Section 134.710 Business Credit and...

Synthesis and characterization of hafnium carbide microcrystal chains with a carbon-rich shell via CVD

International Nuclear Information System (INIS)

Tian, Song; Li, Hejun; Zhang, Yulei; Liu, Sen; Fu, Yangxi; Li, Yixian; Qiang, Xinfa

2013-01-01

Graphical abstract: Novel HfC microcrystal chains have been synthesized via a catalyst-assisted chemical vapor deposition process. SEM results show the chains have a periodically changing diameter and a nanoscale sharpening tip. Analysis of TEM/SAED/EELS/EDX data shows the single-crystal chains grow along a [0 0 1] direction and consist of a HfC core and a thin carbon-rich shell with embedded HfC nanocrystallites surrounding the core. This work achieves the controllable preparation of nanoscale HfC sharpening tips for application as a point electron emission source and facilitates the application of HfC ultrafast laser-triggered tips in attosecond science. Highlights: •HfC microcrystal chains were synthesized by a catalyst-assisted CVD. •The chains grow along a [0 0 1] direction and have a periodically changing diameter. •Single-crystal HfC core is sheathed by a thin carbon-rich shell. •A growth mechanism model is proposed to explain the growth of microcrystal chians. •This work achieves the controllable preparation of nanoscale HfC sharpening tips. -- Abstract: Novel hafnium carbide (HfC) microcrystal chains, with a periodically changing diameter and a nanoscale sharpening tip at the chain end, have been synthesized via a catalyst-assisted chemical vapor deposition (CVD) process. The as-synthesized chains with many octahedral microcrystals have diameters of between several hundreds of nm and 6 μm and lengths of ∼500 μm. TEM diffraction studies show that the chains are single-crystalline HfC and preferentially grow along a [0 0 1] crystal orientation. TEM/EELS/EDX analysis proves the chains are composed of a HfC core and a thin (several tens of nm to 100 nm) carbon-rich shell with the embedded HfC nanocrystallites (typically below 10 nm) surrounding the core. The growth mechanism model for the chains based on the vapor–liquid–solid process, the vapor–solid process, and the HfC crystal growth characteristics is discussed

A biological compression model and its applications.

Science.gov (United States)

Cao, Minh Duc; Dix, Trevor I; Allison, Lloyd

2011-01-01

A biological compression model, expert model, is presented which is superior to existing compression algorithms in both compression performance and speed. The model is able to compress whole eukaryotic genomes. Most importantly, the model provides a framework for knowledge discovery from biological data. It can be used for repeat element discovery, sequence alignment and phylogenetic analysis. We demonstrate that the model can handle statistically biased sequences and distantly related sequences where conventional knowledge discovery tools often fail.

Peyton's 4-Steps-Approach in comparison: Medium-term effects on learning external chest compression – a pilot study

Directory of Open Access Journals (Sweden)

Münster, Tobias

2016-08-01

Full Text Available Introduction: The external chest compression is a very important skill required to maintain a minimum of circulation during cardiac arrest until further medical procedures can be taken. Peyton’s 4-Steps-Approach is one method of skill training, the four steps being:Based on CPR skill training, this method is widely, allegedly predominantly used, although there are insufficient studies on Peyton’s 4-Steps-Approach for skill training in CPR in comparison with other methods of skill training. In our study, we compared the medium- term effects on learning external chest compression with a CPR training device in three different groups: PEY (Peyton’s 4-Steps-Approach, PMOD (Peyton’s 4-Steps-Approach without Step 3 and STDM, the standard model, according to the widely spread method “see one, do one” (this is equal to Peyton’s step 1 and 3.Material and Methods: This prospective and randomised pilot study took place during the summer semester of 2009 at the SkillsLab and Simulation Centre of the University of Cologne (Kölner interprofessionelles Skills Lab und Simulationszentrum - KISS. The subjects were medical students (2 and 3 semester. They volunteered for the study and were randomised in three parallel groups, each receiving one of the teaching methods mentioned above. One week and 5/6 months after the intervention, an objective, structured single assessment was taken. Compression rate, compression depth, correct compressions, and the sum of correct checklist items were recorded. Additionally, we compared cumulative percentages between the groups based on the correct implementation of the resuscitation guidelines during that time.Results: The examined sample consisted of 134 subjects (68% female; age 22±4; PEY: n=62; PMOD: n=31; STDM: n=41. There was no difference between the groups concerning age, gender, pre-existing experience in CPR or time of last CPR course. The only significant difference between the groups was the mean

Causes of seasonal variations of Cs-134/137 activity concentrations in surface air; Ursachen der jahreszeitlichen Schwankungen der Aktivitaetskonzentrationen von Cs-134/137 in der bodennahen Luft

Energy Technology Data Exchange (ETDEWEB)

Hoetzl, H. [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (Germany). Inst. fuer Strahlenschutz; Winkler, R. [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (Germany). Inst. fuer Strahlenschutz

1993-12-31

In winter months maxima of Cs-134/137 activity concentrations in air are observed at several locations in Europe. To clarify this phenomenon, from October 1991 to November 1992 we performed a program for aerosol collection on a short-term scale based on collecting intervals of 48-72 hours. The local meteorological parameters were determined simultaneously. Statistical analysis of these observations reveiled a highly significant positive correlation between Cs-137 activity concentration and the so-called `Stagnationsindex`. Based on this relationship the seasonal variations of Cs-134/137 concentrations in ground-level air can be explained by atmospheric inversion conditions frequently occurring during fall- and wintermonths. (orig.) [Deutsch] Zur Klaerung der an verschiedenen Orten Europas in den Wintermonaten beobachteten Maxima der Cs-134/137-Aktivitaetskonzentrationen in der bodennahen Luft wurde von Oktober 1991 bis November 1992 ein Messgrogramm mit relativ kurzen Zeitintervallen fuer die Aerosolsammlung (48-72 Stunden) durchgefuehrt. Gleichzeitig wurden lokale meteorologische Parameter miterfasst. Die statistische Auswertung der Messergebnisse lieferte eine hochsignifikante positive Korrelation zwischen der Aktivitaetskonzentration von Cs-137 und dem sog. Stagnationsindex. Auf Grund dieses Zusammenhangs lassen sich die saisonalen Schwankungen der Cs-134/137-Luftkonzentrationen mit dem haeufigen Auftreten von austauscharmen Wetterlagen in den Herbst- und Wintermonaten erklaeren. (orig.)

A hybrid data compression approach for online backup service

Science.gov (United States)

Wang, Hua; Zhou, Ke; Qin, MingKang

2009-08-01

With the popularity of Saas (Software as a service), backup service has becoming a hot topic of storage application. Due to the numerous backup users, how to reduce the massive data load is a key problem for system designer. Data compression provides a good solution. Traditional data compression application used to adopt a single method, which has limitations in some respects. For example data stream compression can only realize intra-file compression, de-duplication is used to eliminate inter-file redundant data, compression efficiency cannot meet the need of backup service software. This paper proposes a novel hybrid compression approach, which includes two levels: global compression and block compression. The former can eliminate redundant inter-file copies across different users, the latter adopts data stream compression technology to realize intra-file de-duplication. Several compressing algorithms were adopted to measure the compression ratio and CPU time. Adaptability using different algorithm in certain situation is also analyzed. The performance analysis shows that great improvement is made through the hybrid compression policy.

Halftoning processing on a JPEG-compressed image

Science.gov (United States)

Sibade, Cedric; Barizien, Stephane; Akil, Mohamed; Perroton, Laurent

2003-12-01

Digital image processing algorithms are usually designed for the raw format, that is on an uncompressed representation of the image. Therefore prior to transforming or processing a compressed format, decompression is applied; then, the result of the processing application is finally re-compressed for further transfer or storage. The change of data representation is resource-consuming in terms of computation, time and memory usage. In the wide format printing industry, this problem becomes an important issue: e.g. a 1 m2 input color image, scanned at 600 dpi exceeds 1.6 GB in its raw representation. However, some image processing algorithms can be performed in the compressed-domain, by applying an equivalent operation on the compressed format. This paper is presenting an innovative application of the halftoning processing operation by screening, to be applied on JPEG-compressed image. This compressed-domain transform is performed by computing the threshold operation of the screening algorithm in the DCT domain. This algorithm is illustrated by examples for different halftone masks. A pre-sharpening operation, applied on a JPEG-compressed low quality image is also described; it allows to de-noise and to enhance the contours of this image.

Stage dependent expression and tumor suppressive function of FAM134B (JK1) in colon cancer.

Science.gov (United States)

Islam, Farhadul; Gopalan, Vinod; Wahab, Riajul; Smith, Robert A; Qiao, Bin; Lam, Alfred King-Yin

2017-01-01

The aims of the present study are to investigate sub-cellular location, differential expression in different cancer stages and functional role of FAM134B in colon cancer development. FAM134B expression was studied and quantified at protein and mRNA levels in cell lines using immunocytochemistry, Western blot and real-time PCR. In vitro functional assays and an in vivo xenotransplantation mouse models were used to investigate the molecular role of FAM134B in cancer cell biology in response to FAM134B silencing with shRNA lentiviral particles. FAM134B protein was noted in both cytoplasm and nuclei of cancer cells. In cancer cells derived from stage IV colon cancer, FAM134B expression was remarkably reduced when compared to non-cancer colon cells and cancer cells derived from stage II colon cancer. FAM134B knockdown significantly (P colon cancer cells following lentiviral transfection. Furthermore, FAM134B suppression significantly increased (34-52%; P cancer suppressor gene in colon cancer. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

A comparative experimental study on engine operating on premixed charge compression ignition and compression ignition mode

Directory of Open Access Journals (Sweden)

Bhiogade Girish E.

2017-01-01

Full Text Available New combustion concepts have been recently developed with the purpose to tackle the problem of high emissions level of traditional direct injection Diesel engines. A good example is the premixed charge compression ignition combustion. A strategy in which early injection is used causing a burning process in which the fuel burns in the premixed condition. In compression ignition engines, soot (particulate matter and NOx emissions are an extremely unsolved issue. Premixed charge compression ignition is one of the most promising solutions that combine the advantages of both spark ignition and compression ignition combustion modes. It gives thermal efficiency close to the compression ignition engines and resolves the associated issues of high NOx and particulate matter, simultaneously. Premixing of air and fuel preparation is the challenging part to achieve premixed charge compression ignition combustion. In the present experimental study a diesel vaporizer is used to achieve premixed charge compression ignition combustion. A vaporized diesel fuel was mixed with the air to form premixed charge and inducted into the cylinder during the intake stroke. Low diesel volatility remains the main obstacle in preparing premixed air-fuel mixture. Exhaust gas re-circulation can be used to control the rate of heat release. The objective of this study is to reduce exhaust emission levels with maintaining thermal efficiency close to compression ignition engine.

SeqCompress: an algorithm for biological sequence compression.

Science.gov (United States)

Sardaraz, Muhammad; Tahir, Muhammad; Ikram, Ataul Aziz; Bajwa, Hassan

2014-10-01

The growth of Next Generation Sequencing technologies presents significant research challenges, specifically to design bioinformatics tools that handle massive amount of data efficiently. Biological sequence data storage cost has become a noticeable proportion of total cost in the generation and analysis. Particularly increase in DNA sequencing rate is significantly outstripping the rate of increase in disk storage capacity, which may go beyond the limit of storage capacity. It is essential to develop algorithms that handle large data sets via better memory management. This article presents a DNA sequence compression algorithm SeqCompress that copes with the space complexity of biological sequences. The algorithm is based on lossless data compression and uses statistical model as well as arithmetic coding to compress DNA sequences. The proposed algorithm is compared with recent specialized compression tools for biological sequences. Experimental results show that proposed algorithm has better compression gain as compared to other existing algorithms. Copyright © 2014 Elsevier Inc. All rights reserved.

High temperature strengthening mechanism of hafnium carbide in a tungsten-rhenium matrix

International Nuclear Information System (INIS)

Luo, A.; Shin, K.S.; Jacobson, D.L.

1991-01-01

The interrelationship between the testing temperature and HfC strength increment of an arc-melted W-3.6Re-0.4HfC was determined from 1950 K to 2980 K in a vacuum of better than 1.3x10 -5 Pa (10 -7 torr). The present research was focused on the characteristic temperature at which the rapid coarsening of HfC particles occurred and the effect of the second-phase particle size on the high temperature strength properties of this material. It was found that the HfC particle strengthening was effective in a W-Re matrix up to a characteristic temperature of 2450 K in the short-term tensile test. Carbon was found to be the rate-limiting solute in the HfC particle growth. The strength of HfC strengthened alloy at temperature above 0.5 T m is proportional to the square root of particle volume fraction. The yield strengths of W-3.6Re-0.26HfC calculated based on the particle statistical distribution had good agreement with the experimental values from 1950 K to 2980 K. Besides, an addition of 0.26 percent HfC in tungsten resulted in about 28 percent increase in the activation energy of plastic deformation at high temperatures

Foliar uptake of 134Cs and 85Sr in strawberry as function by leaf age

International Nuclear Information System (INIS)

Fortunati, P.; Brambilla, M.; Speroni, F.; Carini, F.

2004-01-01

In this paper a study of the foliar uptake and translocation of 134 Cs and 85 Sr in a herbaceous fruit plant is presented. In particular, absorption, translocation and loss of these radionuclides in strawberry plants have been studied in relation to the age of contaminated leaves. Strawberry plants were contaminated by distributing droplets of an aqueous solution containing 134 CsCl and 85 SrCl 2 on the surface of two leaves per plant. One half of the plants was contaminated through two young leaves, a second half through two old leaves. Sets of plants were collected 1 day, 7 days and 15 days after contamination. One half of them was rinsed with double distilled water before gamma analysis. Rinsing contaminated leaves removes on average 55% of the applied 134 Cs and 45% of 85 Sr. The activity removed decreases during the 15 days of the experimental study, both for 134 Cs and for 85 Sr, suggesting an increase in foliar absorption during this period. The activity removed does not differ between old and young leaves. 'External loss' is lower for young than old contaminated leaves. 'Internal loss' through translocation occurs mainly for 134 Cs. Translocation coefficients from contaminated leaves to fruits are two orders of magnitude higher for 134 Cs (4.0%), than for 85 Sr (0.05%). Leaf to fruit translocation coefficients for 134 Cs are higher from young leaves (5.8%), than from old leaves (2.3%)

Environmental Assessment for Construction of Multiple Roadway Improvement Projects MacDill AFB, Florida

Science.gov (United States)

2011-01-01

chlorine, freon, paints, thinners, oils, lubricants, compressed gases, pesticides, herbicides, nitrates, and chromates . A detailed tracking and...prolific beneficiaries of tl1e earmark system. In the three years since pub- lic disclosure of earmark LEGAL ADVERTISEMENT . PUBLIC NOTICE - UN~TED...ago: AI Gc legal fight to expand r Otic om GN (all bet ’fl?is offer i of your hem certified LEGAl. ADVERTISE ~ lENT ~ ,.._J) PUBLIC NOTICE

Radiological Image Compression

Science.gov (United States)

Lo, Shih-Chung Benedict

The movement toward digital images in radiology presents the problem of how to conveniently and economically store, retrieve, and transmit the volume of digital images. Basic research into image data compression is necessary in order to move from a film-based department to an efficient digital -based department. Digital data compression technology consists of two types of compression technique: error-free and irreversible. Error -free image compression is desired; however, present techniques can only achieve compression ratio of from 1.5:1 to 3:1, depending upon the image characteristics. Irreversible image compression can achieve a much higher compression ratio; however, the image reconstructed from the compressed data shows some difference from the original image. This dissertation studies both error-free and irreversible image compression techniques. In particular, some modified error-free techniques have been tested and the recommended strategies for various radiological images are discussed. A full-frame bit-allocation irreversible compression technique has been derived. A total of 76 images which include CT head and body, and radiographs digitized to 2048 x 2048, 1024 x 1024, and 512 x 512 have been used to test this algorithm. The normalized mean -square-error (NMSE) on the difference image, defined as the difference between the original and the reconstructed image from a given compression ratio, is used as a global measurement on the quality of the reconstructed image. The NMSE's of total of 380 reconstructed and 380 difference images are measured and the results tabulated. Three complex compression methods are also suggested to compress images with special characteristics. Finally, various parameters which would effect the quality of the reconstructed images are discussed. A proposed hardware compression module is given in the last chapter.

13 CFR 134.711 - Will the Judge permit discovery and oral hearings?

Science.gov (United States)

2010-01-01

... Appeals From Women-Owned Small Business Concern (WOSB) and Economically Disadvantaged WOSB Concern (EDWOSB... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Will the Judge permit discovery and oral hearings? 134.711 Section 134.711 Business Credit and Assistance SMALL BUSINESS...

13 CFR 134.705 - What are the requirements for an appeal petition?

Science.gov (United States)

2010-01-01

... Appeals From Women-Owned Small Business Concern (WOSB) and Economically Disadvantaged WOSB Concern (EDWOSB... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false What are the requirements for an appeal petition? 134.705 Section 134.705 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION...

Role of excited CF₃CFHO radicals in the atmospheric chemistry of HFC-134a

DEFF Research Database (Denmark)

Wallington, T.J.; Hurley, M.D.; Fracheboud, J.M.

1996-01-01

with Oz, CF3CFHO + O-2 --> CF3C(O)F + HO2, and decomposition via C-C bond scission, CF3CFHO + M --> CS3 + HC(O)F + M. CF3CFHO radicals were produced by two different reactions: either via the self-reaction of CF3CFHO2 radicals or via the CF3CFHO2 + NO reaction. It was found that decomposition was much...

Neutron Inelastic Scattering on 134Xe at En = 5 - 8 MeV

Science.gov (United States)

Kidd, Mary; Tornow, Werner; Finch, Sean; Krishichayan, Fnu; Bhike, Megha

2017-09-01

Neutrinoless double-beta decay (0 νββ) studies are both the best way to determine the Majorana nature of the neutrino and determine its effective mass. The two main experiments searching for 0 νββ -decay of 136Xe (Q value = 2457.8 keV) are Kamland-Zen and EXO-200. Though both experiments have enriched 136Xe targets, these targets still contain significant quantities of 134Xe. Recently, a new nuclear level was discovered in 134Xe that decays to the ground state emitting a 2485.7 keV gamma ray. The γ-ray production cross section for this branch was found to be on the order of 10 mb for incident neutron energies of 2.5-4.5 MeV. Here, we have extended the investigation of this level to higher incident neutron energies, and further explore the potential neutron-induced backgrounds on both 134Xe and 136Xe for extended neutron energies. We will report our preliminary results for neutron inelastic scattering on 134Xe in applications to 0 νββ decay searches. NSF PHY-1614348, DE-FG02-97ER41033.

FRC translation into a compression coil

International Nuclear Information System (INIS)

Chrien, R.E.

1985-01-01

Several features of the problem of FRC translation into a compression coil are considered. First, the magnitude of the guide field is calculated and found to exceed that which would be applied to a flux conserver. Second, energy conservation is applied to FRC translation from a flux conserver into a compression coil. It is found that a significant temperature decrease is required for translation to be energetically possible. The temperature change depends on the external inductance in the compression circuit. An analogous case is that of a compression region composed of a compound magnet; in this case the temperature change depends on the ratio of inner and outer coil radii. Finally, the kinematics of intermediate translation states are calculated using an ''abrupt transition'' model. It is found, in this model, that the FRC must overcome a potential hill during translation, which requires a small initial velocity

Test of 134Cs, 85,89Sr leaching rate in a resemble vitrifiable cement waste form

International Nuclear Information System (INIS)

Lin Meiqiong; Wei Feng; Yin Qi; Fan Xianhua; Xu Shengli; Li Yongde

2003-01-01

A novel material--resemble vitrifiable cement for conditioning low and mediate level radioactive waste has been developed. Waste form has been characterized for their physical and chemical performance, phase composition. The cement formulation has been patented. In this experiment the cement is mixed with simulated wastes spiked with 134 Cs and 85,89 Sr by 5 min at least. The Ratio of the waste to the cement is 0.45-0.55. The mixture is packed into cylindrical molds which has the same dimension of diameter and height . The grouts are cured for a period of 28 d in a room temperature curing chamber at an atmospheric pressure. The cured waste form is then completely immersed into deionized water. According to standard GB7023-86, leaching rate of 134 Cs and 85,89 Sr are measured. The result shows that the leaching rate of the species 134 Cs and 85,89 Sr is to be on the order 10 -4 and 10 -5 on the 42 d immersion, respectively and is better than that of commercial cement

Adsorption of *sp134*Cs onto two different types of roof materials

International Nuclear Information System (INIS)

Quenild, C.; Tveten, U.

1983-01-01

The report relates to a subproject under a Nordic project called ''Large reactor accidents - consequences and mitigating actions''. Natural decontamination of two types of roof material, typical of Norwegian and Swedish buildings, was examined. The roofs were contaminated with *sp134*Cs. After two days with 7 mm precipitation, the remaining activity on the tar-paper roof was 97% and on the steel roof 29%. After 8 months the remaining activity was 61% on the tar-paper roof and 22% on the steel roof. In spring *sp134*Cs was spread upon an 8 cm thick layer of fresh snow on an additional tar-paper roof. After 3 montsh and 191 mm precipitation the remaining activity was 59%. All results are based upon *sp134*Cs in collected run-off water.(Auth.)

Intercomparison of radionuclides measurements in marine cockle flesh sample IAEA-134

Energy Technology Data Exchange (ETDEWEB)

Ballestra, S; Gastaud, J; Lopez, J J; Parsi, P; Vas, D

1993-08-01

The results of an intercomparison exercise on a cockle flesh sample from Irish Sea, IAEA-134, designed for the determination of artificial and natural radionuclide levels, are reported. The data from 134 laboratories representing 49 countries have been evaluated. The following are the recommended values, with confidence intervals, for {sup 40}K, {sup 60}Co, {sup 137}Cs, and 2{sup 39+240}Pu (Reference date: 1 January 1992). Information values for {sup 90}Sr, {sup 106}Ru, {sup 125}Sb, {sup 134}Cs, {sup 154}Eu, {sup 155}Eu, {sup 210}Pb, {sup 210}Po, {sup 226}Ra, {sup 228}Ra, {sup 228}Th, {sup 230}Th, {sup 232}Th, {sup 234}U, {sup 235}U, {sup 238}U, {sup 238}Pu and {sup 241}Am are also reported. All the following values are expressed in Bq kg{sup -1} (dry weight). (author)

Experimental Study of Evaporative Heat Transfer Characteristics of R-134a with Channel-Bending Angle in Microchannel Heat Exchangers

International Nuclear Information System (INIS)

Lee, Hae Seung; Jeon, Dong Soon; Kim, Young Lyoul; Kim, Seon Chang

2010-01-01

Experimental investigations have been carried out to examine the evaporative heat transfer characteristics of R-134a with the channel-bending angle (CBA) in microchannel heat exchangers. In this study, we examined the effects of evaporation temperature and Reynolds number of R-134a on the evaporative heat transfer characteristics of R-134a in microchannel heat exchangers with CBAs of 120 .deg. , 150 .deg. , and 180 .deg. under counterflow conditions. Experimental results show that the evaporative heat transfer rate and evaporative heat transfer coefficient increased with an increase in the Reynolds number of R-134a. Further, the evaporative heat transfer rate corresponding to CBAs of 120 .deg. and 150 .deg. increased to values greater than the evaporative heat transfer rate corresponding to 180 .deg. by approximately 17.1% and 13.3%, respectively, for evaporating temperatures in the range 4.9-14.9 .deg. C. The evaporative heat transfer coefficient was affected by the channel angle with increasing evaporative heat transfer coefficient at small channel bending angle

Mathematical transforms and image compression: A review

Directory of Open Access Journals (Sweden)

Satish K. Singh

2010-07-01

Full Text Available It is well known that images, often used in a variety of computer and other scientific and engineering applications, are difficult to store and transmit due to their sizes. One possible solution to overcome this problem is to use an efficient digital image compression technique where an image is viewed as a matrix and then the operations are performed on the matrix. All the contemporary digital image compression systems use various mathematical transforms for compression. The compression performance is closely related to the performance by these mathematical transforms in terms of energy compaction and spatial frequency isolation by exploiting inter-pixel redundancies present in the image data. Through this paper, a comprehensive literature survey has been carried out and the pros and cons of various transform-based image compression models have also been discussed.

Quick, save the ozone

International Nuclear Information System (INIS)

Weber, J.

1993-01-01

Last December, after an all-out, nearly $500 million development effort, an Imperial Chemical Industries (ICI) plant in Louisiana was the first world-scale US facility to start pumping out HFC 134a, an alternative to CFC12, the chemical that accounts for more than 50% of CFC use. The saga of 134a is an object lesson in how a global crisis can compel governments and companies to transform technology far faster than either thought possible. With deadlines for phasing out CFCs closing in, ICI and its rivals, Du Pont and Elf, developed technology speedily by constructing factories even while their choice molecules were still being tested. ICI slashed the time it takes to commercialize a technology from the industry norm of more than a decade to only five years. If companies are forced to act on environmental issues, they do it

Experimental studies on the biokinetics of Cs-134 and Cd-109 in the blood cockle (Anadara granosa)

International Nuclear Information System (INIS)

Norfaizal Mohamed; Nita Salina Abu Bakar; Zal Uyun Wan Mahmood; Nur Hidaya Dmuliany Mohd Sidek; Zaharudin Ahmad

2010-01-01

Bioaccumulation and depuration study under controlled laboratory conditions of Cs and Cd in Anadara granosa collected at coastal Kapar, Selangor was carried out using respective radiotracer, Cs-134 and Cd-109. The radioactivity of Cs-134 and Cd-109 were determined using high resolution hyper germanium detector. Our results demonstrate that Cd-109 was accumulated efficiently by this species, except Cs-134. The steady state concentration factor (CF) for accumulation of Cs-134 and Cd-109 from seawater was estimated to be about 5.86 and 51.31, respectively. For the depuration stage, loss kinetics of Cs-134 and Cd-109 was best described by 2-compartment exponential model. Results shown that A. granosa exposed to Cs-134 have a total loss of 69% in compared to 19 % of Cd-109. Results gained in this experiment are a baseline data to evaluate future released of radioactive material from nuclear power programme facilities within this region. (author)

Poor chest compression quality with mechanical compressions in simulated cardiopulmonary resuscitation: a randomized, cross-over manikin study.

Science.gov (United States)

Blomberg, Hans; Gedeborg, Rolf; Berglund, Lars; Karlsten, Rolf; Johansson, Jakob

2011-10-01

Mechanical chest compression devices are being implemented as an aid in cardiopulmonary resuscitation (CPR), despite lack of evidence of improved outcome. This manikin study evaluates the CPR-performance of ambulance crews, who had a mechanical chest compression device implemented in their routine clinical practice 8 months previously. The objectives were to evaluate time to first defibrillation, no-flow time, and estimate the quality of compressions. The performance of 21 ambulance crews (ambulance nurse and emergency medical technician) with the authorization to perform advanced life support was studied in an experimental, randomized cross-over study in a manikin setup. Each crew performed two identical CPR scenarios, with and without the aid of the mechanical compression device LUCAS. A computerized manikin was used for data sampling. There were no substantial differences in time to first defibrillation or no-flow time until first defibrillation. However, the fraction of adequate compressions in relation to total compressions was remarkably low in LUCAS-CPR (58%) compared to manual CPR (88%) (95% confidence interval for the difference: 13-50%). Only 12 out of the 21 ambulance crews (57%) applied the mandatory stabilization strap on the LUCAS device. The use of a mechanical compression aid was not associated with substantial differences in time to first defibrillation or no-flow time in the early phase of CPR. However, constant but poor chest compressions due to failure in recognizing and correcting a malposition of the device may counteract a potential benefit of mechanical chest compressions. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

NRGC: a novel referential genome compression algorithm.

Science.gov (United States)

Saha, Subrata; Rajasekaran, Sanguthevar

2016-11-15

Next-generation sequencing techniques produce millions to billions of short reads. The procedure is not only very cost effective but also can be done in laboratory environment. The state-of-the-art sequence assemblers then construct the whole genomic sequence from these reads. Current cutting edge computing technology makes it possible to build genomic sequences from the billions of reads within a minimal cost and time. As a consequence, we see an explosion of biological sequences in recent times. In turn, the cost of storing the sequences in physical memory or transmitting them over the internet is becoming a major bottleneck for research and future medical applications. Data compression techniques are one of the most important remedies in this context. We are in need of suitable data compression algorithms that can exploit the inherent structure of biological sequences. Although standard data compression algorithms are prevalent, they are not suitable to compress biological sequencing data effectively. In this article, we propose a novel referential genome compression algorithm (NRGC) to effectively and efficiently compress the genomic sequences. We have done rigorous experiments to evaluate NRGC by taking a set of real human genomes. The simulation results show that our algorithm is indeed an effective genome compression algorithm that performs better than the best-known algorithms in most of the cases. Compression and decompression times are also very impressive. The implementations are freely available for non-commercial purposes. They can be downloaded from: http://www.engr.uconn.edu/~rajasek/NRGC.zip CONTACT: rajasek@engr.uconn.edu. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Rate of sediment intake by midge larvae (Chironomus plumosus: diptera) using a 134Cs tracer

International Nuclear Information System (INIS)

Gerking, S.D.; Berg, A.; Gerard, P.

1976-01-01

The food intake and assimilation of midge larvae (Chironomus plumosus) were determined by a 134 Cs technique which utilized the principle that the rate of excretion can be substituted for the rate of absorption when the larvae are in 134 Cs equilibrium with their environment. The larvae were introduced into contaminated sediments until they reached 134 Cs equilibrium. The time of reaching equilibrium and levels of radioactivity were the same at 10 and at 15 0 C (70 hr at a level of 1367 dpm/mg of larva) and were both significantly different from that at 20 0 C (40 hr at 1062 dpm/mg of larva). Cesium-134 elimination was followed on equilibrated larvae for as long as 330 hr. One egestion compartment (fast) and two excretion (medium and slow) compartments could be recognized at the three experimental temperatures. The loss rates from the second and third compartments at 10 0 C were slower and stretched out over longer time periods compared with those at 15 0 C, while the loss rate from the first compartment was much more comparable at the two temperatures. The first and second compartments merged at 20 0 C, while the slow compartment rose to almost three times that at 15 0 C. The food intake was nearly the same at the three temperatures (0.0986, 0.0893 and 0.0876 mg dry sediment/mg of larva/day). Thus, the larvae relied on an increase in assimilation to meet increased metabolic requirements at higher temperatures rather than depending upon a higher food intake. The gross growth efficiencies varied with temperature from 9.9 percent at 10 0 C to 15.1 percent at 15 0 C

WSNs Microseismic Signal Subsection Compression Algorithm Based on Compressed Sensing

Directory of Open Access Journals (Sweden)

Zhouzhou Liu

2015-01-01

Full Text Available For wireless network microseismic monitoring and the problems of low compression ratio and high energy consumption of communication, this paper proposes a segmentation compression algorithm according to the characteristics of the microseismic signals and the compression perception theory (CS used in the transmission process. The algorithm will be collected as a number of nonzero elements of data segmented basis, by reducing the number of combinations of nonzero elements within the segment to improve the accuracy of signal reconstruction, while taking advantage of the characteristics of compressive sensing theory to achieve a high compression ratio of the signal. Experimental results show that, in the quantum chaos immune clone refactoring (Q-CSDR algorithm for reconstruction algorithm, under the condition of signal sparse degree higher than 40, to be more than 0.4 of the compression ratio to compress the signal, the mean square error is less than 0.01, prolonging the network life by 2 times.

Idiopathic urolithiasis in Tunisian children: A report of 134 cases

Directory of Open Access Journals (Sweden)

A Alaya

2013-01-01

Full Text Available We evaluated the metabolic and the nutritional aspects of 134 urolithiasis children in order to outline the characteristics of idiopathic urolithiasis in children. This prospective study group of 134 children (56 females, 78 males with renal calculi was evaluated. The age range of the patients was six months to 16 years. A dietary survey was performed on every child. All patients were investigated with respect to stone localization and serum and urine risk factors. Statistical analysis of data was carried out using software SPSS 11.0 for Windows. Hypercalciuria was the most common risk factor detected in this group (28.3%. A decrease of water intake was noted in all age groups, especially in the rural area (549.6 mL/day vs. 1150.6 mL/day, and there was an increase in animal protein intake in 17 cases (mean: 1.9 g/kg. In addition, increased intake of starchy foods and food with high oxalate content (sorgum were detected in the ten to 16 years age group (51% of our study. Calcium oxalate monohydrate represents the principal component of idiopathic stone (58.2%, which is more frequent in children (68% than in infants (51.7% (P <0.02. The major etiology of idiopathic urolithiasis highlights the influence of dietary habit in stone formers in our country. The increased occurrence of calcium oxalate stones in school age children confirms the change in the etiology of urolithiasis according to age.

Compatibility of manufacturing process fluids with R-134a and polyolester lubricant. Final report

Energy Technology Data Exchange (ETDEWEB)

Cavestri, R.C.; Schooley, D.L. [Imagination Resources, Inc., Dublin, OH (United States)

1996-07-01

This report includes a broad list of processing fluids that are known to be used to manufacture air conditioning and refrigeration products. Sixty-four process fluids from this list were selected for compatibility studies with R-134a and ICI EMKARATE RL32H (32 ISO) polyolester lubricant. Solutions or suspensions of the process fluid residues in polyolester lubricant were heated for 14 days at 175{degrees}C (347{degrees}F) in evacuated sealed glass tubes containing only valve steel coupons. Miscibility tests were performed at 90 wt.% R-134a, 10 wt.% polyolester lubricant with process fluid residue contaminate and were scanned in 10{degrees}C (18{degrees}F) increments over a temperature range of ambient to -40{degrees}C (-40{degrees}F). Any sign of turbidity, haze formation or oil separation was considered the immiscibility point.

All-atom simulation study of protein PTH(1-34) by using the Wang-Landau sampling method

Energy Technology Data Exchange (ETDEWEB)

Kim, Seung-Yeon [Korea National University of Transportation, Chungju (Korea, Republic of); Kwak, Woo-Seop [Chosun University, Gwangju (Korea, Republic of)

2014-12-15

We perform simulations of the N-terminal 34-residue protein fragment PTH(1-34), consisting of 581 atoms, of the 84-residue human parathyroid hormone by using the all-atom ECEPP/3 force field and the Wang-Landau sampling method. Through a massive high-performance computation, the density of states and the partition function Z(T), as a continuous function of T, are obtained for PTH(1-34). From the continuous partition function Z(T), the partition function zeros of PTH(1-34) are evaluated for the first time. From both the specific heat and the partition function zeros, two characteristic transition temperatures are obtained for the all-atom protein PTH(1-34). The higher transition temperature T{sub 1} and the lower transition temperature T{sub 2} of PTH(1-34) can be interpreted as the collapse temperature T{sub θ} and the folding temperature T{sub f} , respectively.

40 CFR 61.134 - Standard: Naphthalene processing, final coolers, and final-cooler cooling towers.

Science.gov (United States)

2010-07-01

... coolers, and final-cooler cooling towers. 61.134 Section 61.134 Protection of Environment ENVIRONMENTAL... Standard: Naphthalene processing, final coolers, and final-cooler cooling towers. (a) No (“zero”) emissions are allowed from naphthalene processing, final coolers and final-cooler cooling towers at coke by...

Separation of 134Cs and 137Cs from 125I solution for medical applications

International Nuclear Information System (INIS)

Ram, Ramu; Dash, Ashutosh; Banerjee, Dayamoy

2015-01-01

While neutron irradiation of natural Xe gas followed by wet chemical dissolution of activation products constitutes a successful paradigm for the small scale production 125 I, the concomitant production of 134 Cs and 137 Cs emerged as the primary impediment which necessitates purification of 125 I solution. This paper describes an ion-exchange chromatographic technique using Resorcinol Formaldehyde (RF) resin to purify 125 I solution from 134 Cs and 137 Cs impurities. A thorough investigation of the adsorption parameters of RF resin was carried out to arrive at the experimental conditions resulting optimum retention of 134 Cs and 137 Cs impurities. Based on the experimental findings, an optimized separation procedure was developed in which the neutron irradiated dissolved products at pH ∝ 13 was passed through a chromatography column containing RF resin where in 134 Cs and 137 Cs impurities gets adsorbed leaving behind 125 I to appear in the effluent. The overall recovery of 125 I was >90% with acceptable purity amenable for clinical applications.

'Wash-out' of Cs-134 and Cs-137 from river sediment; 'Ispiranja' Cs-134 i Cs-137 iz recnog sedimenta

Energy Technology Data Exchange (ETDEWEB)

Skrbic, Z; Conkic, Lj; Bikit, I; Veskovic, M; Slivka, J; Marinkov, L [Institut za Fiziku, Novi Sad Univ. (Yugoslavia)

1988-07-01

Natural elimination and 'wash out' period of the Cs-134 and Cs-137 from the river sediment has been investigated. Obtained results suggest the possibility to describe these processes by exponential low and determination of the corresponding half lives. (author)

Lossless medical image compression with a hybrid coder

Science.gov (United States)

Way, Jing-Dar; Cheng, Po-Yuen

1998-10-01

The volume of medical image data is expected to increase dramatically in the next decade due to the large use of radiological image for medical diagnosis. The economics of distributing the medical image dictate that data compression is essential. While there is lossy image compression, the medical image must be recorded and transmitted lossless before it reaches the users to avoid wrong diagnosis due to the image data lost. Therefore, a low complexity, high performance lossless compression schematic that can approach the theoretic bound and operate in near real-time is needed. In this paper, we propose a hybrid image coder to compress the digitized medical image without any data loss. The hybrid coder is constituted of two key components: an embedded wavelet coder and a lossless run-length coder. In this system, the medical image is compressed with the lossy wavelet coder first, and the residual image between the original and the compressed ones is further compressed with the run-length coder. Several optimization schemes have been used in these coders to increase the coding performance. It is shown that the proposed algorithm is with higher compression ratio than run-length entropy coders such as arithmetic, Huffman and Lempel-Ziv coders.

The synthesis, characterization and optical properties of novel 1,3,4-oxadiazole-containing imidazo[1,5-a]pyridine derivatives

International Nuclear Information System (INIS)

Ge Yanqing; Hao Benqian; Duan Guiyun; Wang Jianwu

2011-01-01

A series of novel substituted 1,3,4-oxadiazole derivatives were synthesized by the reaction of 3-butyl-1-chloroimidazo[1,5-a]pyridine-7-carbohydrazide with propionyl chloride and substituted benzoic chloride in the presence of phosphorus oxychloride. The compounds were characterized using IR, 1 H NMR, 13 C NMR and HRMS. Absorption and fluorescence spectra were measured in dichloromethane; an intense absorption maxima was noted at ca. 290 nm and emission maxima was noted at ca. 470 nm. The absorption spectra of the 1,3,4-oxadiazole derivatives reveal that a phenyl and an ethyl group attached to the 1,3,4-oxadiazole ring markedly influenced the maximum absorption. The structures based on density function theory (DFT) calculation show planar configurations for the compounds. The calculated molecular orbital correlates well with their absorption. - Research highlights: → Novel imidazo[1,5-a]pyridine derivatives were synthesized. → The structures were determined by IR, 1 H NMR, 13 C NMR and HRMS spectra. → We investigated the absorption and fluorescence spectral characteristics of the compounds. → The side group in 1,3,4-oxadiazole ring can affect its photophysical properties markedly. → Quantum calculation correlates well with their absorption.

FRC translation into a compression coil

International Nuclear Information System (INIS)

Chrien, R.E.

1986-01-01

The equilibrium and translational kinematics of Field-Reversed Configurations (FRCs) in a cylindrical coil which does not conserve flux are problems that arise in connection with adiabatic compressional heating. In this paper, they consider several features of the problem of FRC translation into a compression coil. First, the magnitude of the guide field is calculated and found to exceed that which would be applied to a flux conserver. Second, energy conservation is applied to FRC translation from a flux conserver into a compression coil. It is found that a significant temperature decrease is required for translation to be energetically possible. The temperature change depends on the external inductance in the compression circuit. An analogous case is that of a compression region composed of a compound magnet; in this case the temperature change depends on the ratio of inner and outer coil radii. Finally, the kinematics of intermediate translation states are calculated using an abrupt transition model. It is found, in this model, that the FRC must overcome a potential hill during translation, which requires a small initial velocity

Dual compression is not an uncommon type of iliac vein compression syndrome.

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Shi, Wan-Yin; Gu, Jian-Ping; Liu, Chang-Jian; Lou, Wen-Sheng; He, Xu

2017-09-01

Typical iliac vein compression syndrome (IVCS) is characterized by compression of left common iliac vein (LCIV) by the overlying right common iliac artery (RCIA). We described an underestimated type of IVCS with dual compression by right and left common iliac arteries (LCIA) simultaneously. Thirty-one patients with IVCS were retrospectively included. All patients received trans-catheter venography and computed tomography (CT) examinations for diagnosing and evaluating IVCS. Late venography and reconstructed CT were used for evaluating the anatomical relationship among LCIV, RCIA and LCIA. Imaging manifestations as well as demographic data were collected and evaluated by two experienced radiologists. Sole and dual compression were found in 32.3% (n = 10) and 67.7% (n = 21) of 31 patients respectively. No statistical differences existed between them in terms of age, gender, LCIV diameter at the maximum compression point, pressure gradient across stenosis, and the percentage of compression level. On CT and venography, sole compression was commonly presented with a longitudinal compression at the orifice of LCIV while dual compression was usually presented as two types: one had a lengthy stenosis along the upper side of LCIV and the other was manifested by a longitudinal compression near to the orifice of external iliac vein. The presence of dual compression seemed significantly correlated with the tortuous LCIA (p = 0.006). Left common iliac vein can be presented by dual compression. This type of compression has typical manifestations on late venography and CT.

Post-Dryout Heat Transfer to a Refrigerant Flowing in Horizontal Evaporator Tubes

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Mori, Hideo; Yoshida, Suguru; Kakimoto, Yasushi; Ohishi, Katsumi; Fukuda, Kenichi

Studies of the post-dryout heat transfer were made based on the experimental data for HFC-134a flowing in horizontal smooth and spiral1y grooved (micro-fin) tubes and the characteristics of the post-dryout heat transfer were c1arified. The heat transfer coefficient at medium and high mass flow rates in the smooth tube was lower than the single-phase heat transfer coefficient of the superheated vapor flow, of which mass flow rate was given on the assumption that the flow was in a thermodynamic equilibrium. A prediction method of post-dryout heat transfer coefficient was developed to reproduce the measurement satisfactorily for the smooth tube. The post dryout heat transfer in the micro-fin tube can be regarded approximately as a superheated vapor single-phase heat transfer.

Relationship between medical compression and intramuscular pressure as an explanation of a compression paradox.

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Uhl, J-F; Benigni, J-P; Cornu-Thenard, A; Fournier, J; Blin, E

2015-06-01

Using standing magnetic resonance imaging (MRI), we recently showed that medical compression, providing an interface pressure (IP) of 22 mmHg, significantly compressed the deep veins of the leg but not, paradoxically, superficial varicose veins. To provide an explanation for this compression paradox by studying the correlation between the IP exerted by medical compression and intramuscular pressure (IMP). In 10 legs of five healthy subjects, we studied the effects of different IPs on the IMP of the medial gastrocnemius muscle. The IP produced by a cuff manometer was verified by a Picopress® device. The IMP was measured with a 21G needle connected to a manometer. Pressure data were recorded in the prone and standing positions with cuff manometer pressures from 0 to 50 mmHg. In the prone position, an IP of less than 20 did not significantly change the IMP. On the contrary, a perfect linear correlation with the IMP (r = 0.99) was observed with an IP from 20 to 50 mmHg. We found the same correlation in the standing position. We found that an IP of 22 mmHg produced a significant IMP increase from 32 to 54 mmHg, in the standing position. At the same time, the subcutaneous pressure is only provided by the compression device, on healthy subjects. In other words, the subcutaneous pressure plus the IP is only a little higher than 22 mmHg-a pressure which is too low to reduce the caliber of the superficial veins. This is in accordance with our standing MRI 3D anatomical study which showed that, paradoxically, when applying low pressures (IP), the deep veins are compressed while the superficial veins are not. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

A checkpoint compression study for high-performance computing systems

Energy Technology Data Exchange (ETDEWEB)

Ibtesham, Dewan [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Computer Science; Ferreira, Kurt B. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Scalable System Software Dept.; Arnold, Dorian [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Computer Science

2015-02-17

As high-performance computing systems continue to increase in size and complexity, higher failure rates and increased overheads for checkpoint/restart (CR) protocols have raised concerns about the practical viability of CR protocols for future systems. Previously, compression has proven to be a viable approach for reducing checkpoint data volumes and, thereby, reducing CR protocol overhead leading to improved application performance. In this article, we further explore compression-based CR optimization by exploring its baseline performance and scaling properties, evaluating whether improved compression algorithms might lead to even better application performance and comparing checkpoint compression against and alongside other software- and hardware-based optimizations. Our results highlights are: (1) compression is a very viable CR optimization; (2) generic, text-based compression algorithms appear to perform near optimally for checkpoint data compression and faster compression algorithms will not lead to better application performance; (3) compression-based optimizations fare well against and alongside other software-based optimizations; and (4) while hardware-based optimizations outperform software-based ones, they are not as cost effective.

Human CD134 (OX40) expressed on T cells plays a key role for human herpesvirus 6B replication after allogeneic hematopoietic stem cell transplantation.

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Nagamata, Satoshi; Nagasaka, Miwako; Kawabata, Akiko; Kishimoto, Kenji; Hasegawa, Daiichiro; Kosaka, Yoshiyuki; Mori, Takeshi; Morioka, Ichiro; Nishimura, Noriyuki; Iijima, Kazumoto; Yamada, Hideto; Kawamoto, Shinichiro; Yakushijin, Kimikazu; Matsuoka, Hiroshi; Mori, Yasuko

2018-05-01

CD134 (OX40), which is a cellular receptor for human herpesvirus-6B (HHV-6B) and expresses on activated T cells, may play a key role for HHV-6B replication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Therefore, we examined the CD134 expression on T cells and HHV-6B replication after allo-HSCT, and analyzed the correlation between them. Twenty-three patients after allo-HSCT were enrolled. The percentages of CD134-positive cells within the CD4 + and CD8 + cell populations were measured by flow cytometry, and the viral copy number of HHV-6B was simultaneously quantified by real-time PCR. The correlation between CD134 and HHV-6B viral load was then statistically analyzed. HHV-6B reactivation occurred in 11 of 23 patients (47.8%). CD134 expression was seen on T cells and was coincident with the time of peak viral load. The percentage of CD134-positive cells decreased significantly when HHV-6B DNA disappeared (p = .005 in CD4 + T cells, p = .02 in CD8 + T cells). In the 4 patients who underwent umbilical cord blood transplantation (UCBT), the viral load varied with the percentage of CD134-positive cells. In the comparison between the HHV-6B reactivation group and non-reactivation group, maximum percentages of CD134-positive cells among CD4 + T cells in reactivation group were significantly higher than those in non-reactivation group (p = .04). This is the first study to show that a correlation of CD134 expression on T cells with HHV-6B replication after allo-HSCT, especially in UCBT. The results possibly indicate that CD134 on T cells plays a key role for HHV-6B replication after allo-HSCT. Copyright © 2018 Elsevier B.V. All rights reserved.

Energy consumption estimation for greenhouse gas separation processes by clathrate hydrate formation

International Nuclear Information System (INIS)

Tajima, Hideo; Yamasaki, Akihiro; Kiyono, Fumio

2004-01-01

The process energy consumption was estimated for gas separation processes by the formation of clathrate hydrates. The separation process is based on the equilibrium partition of the components between the gaseous phase and the hydrate phase. The separation and capturing processes of greenhouse gases were examined in this study. The target components were hydrofluorocarbon (HFC-134a) from air, sulfur hexafluoride (SF 6 ) from nitrogen, and CO 2 from flue gas. Since these greenhouse gases would form hydrates under much lower pressure and higher temperature conditions than the accompanying components, the effective capturing of the greenhouse gases could be achieved by using hydrate formation. A model separation process for each gaseous mixture was designed from the basis of thermodynamics, and the process energy consumption was estimated. The obtained results were then compared with those for conventional separation processes such as liquefaction separation processes. For the recovery of SF 6 , the hydrate process is preferable to liquefaction process in terms of energy consumption. On the other hand, the liquefaction process consumes less energy than the hydrate process for the recovery of HFC-134a. The capturing of CO 2 by the hydrate process from a flue gas will consume a considerable amount of energy; mainly due to the extremely high pressure conditions required for hydrate formation. The influences of the operation conditions on the heat of hydrate formation were elucidated by sensitivity analysis. The hydrate processes for separating these greenhouse gases were evaluated in terms of reduction of global warming potential (GWP)

Synthesis of novel 2,5-disubstituted-1,3,4-selenadiazoles from fatty acid hydrazides

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Himani Varshney

2018-01-01

Full Text Available A series of novel unsaturated hydroxy and non-hydroxy fatty acid residue substituted 1,3,4-selenadiazoles were described here. These derivatives were synthesized from the reaction of fatty acid hydrazide 1(a–d with acetyl chloride in the presence of anhydrous sodium carbonate in tetrahydrofuran and water at 0 °C, to form N′-acetyl undec-10-enoic hydrazide 2a, N′-acetyl-(9Z-octadec-9-enoic hydrazide 2b, N′-acetyl-(9Z, 12R-12-hydroxy-9-enoic hydrazide 2c, and N′-acetyl-(9R, 12Z-9-hydroxy-12-enoic hydrazide 2d. Then these hydrazines (dicarbonyl compound on reaction with Woollin’s reagent (WR in toluene led to the corresponding 2-(dec-9′-enyl-5-methyl-1,3,4-selenadiazole 3a, 2-[(8′Z-heptadec-8′-enyl]-5-methyl-1,3,4-selenadiazole 3b, 2-[(8′Z, 11′R-11′-hydroxy-octadec-8′-enyl]-5-methyl-1,3,4-selenadiazole 3c, and 2-[(8′R, 11′Z-8′-hydroxy-octadec-11′-enyl]-5-methyl-1,3,4-selenadiazole 3d, respectively. These synthesized compounds were characterized on the basis of IR, 1H NMR, 13C NMR, mass spectra and elemental analysis results.

Neutron-induced Backgrounds in 134Xe for Large-Scale Neutrinoless Double-Beta Decay Experiments

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Moriguchi, Nina; Kidd, Mary; Tornow, Werner