WorldWideScience

Sample records for low-temperature heat treatment

  1. Low temperature nuclear heat

    Energy Technology Data Exchange (ETDEWEB)

    Kotakorpi, J.; Tarjanne, R. [comps.

    1977-08-01

    The meeting was concerned with the use of low grade nuclear heat for district heating, desalination, process heat, and agriculture and aquaculture. The sessions covered applications and demand, heat sources, and economics.

  2. Heat treatments and low temperature fracture toughness of a Ti-6A1-4V alloy

    International Nuclear Information System (INIS)

    Nagai, K.; Hiraga, K.; Ishikawa, K.; Ogata, T.

    1984-01-01

    Titanium alloy is one of the reliable structural materials for cryogenic use owing to its high strength, high specific strength and low thermal conductivity. Heat treatment is one method of controlling the normally poor fracture toughness of this alloy at ambient temperature. However, there have been few attempts to improve the low temperature fracture toughness by heat treatment. This study was conducted to elucidate the effects of heat treatments on the low temperature fracture toughness in a Ti-6A1-4V alloy. The effects of the heat treatments were as follows: the beta treatment was a very feasible method to improve the low temperature fracture properties; the alpha+beta treatment was favorable for the increment in the low temperature ductility but did not largely improve the fracture toughness; the double treatment yielded good ductility but was not useful for improving the fracture toughness

  3. Low-temperature synthesis of allyl dimethylamine by selective heating under microwave irradiation used for water treatment

    International Nuclear Information System (INIS)

    Tian Binghui; Luan Zhaokun; Li Mingming

    2005-01-01

    Low-temperature synthesis of allyl dimethylamine (ADA) by selective heating under microwave irradiation (MI) used for water treatment is investigated. The effect of MI, ultrasound irradiation (UI) and conventional heating on yield of ADA, reaction time and the flocculation efficiency of polydiallyl dimethylammunion chloride (PDADMAC) prepared form ADA were studied. The results show that by selective heating at low temperature, MI not only increases yield of ADA and reduces reaction time, but also greatly enhances the flocculation efficiency of PDADMAC

  4. Predicting outgrowth and inactivation of Clostridium perfringens in meat products during low temperature long time heat treatment

    DEFF Research Database (Denmark)

    Duan, Zhi; Holst Hansen, Terese; Hansen, Tina Beck

    OBJECTIVE Sous-vide cooking and molecular gastronomy has started a wave of experimenting with Low Temperature Long Time (LTLT) heat treatments. Heat treatments, at temperatures as low as 50°C, have been suggested by celebrity chefs. LTLT treatments often take hours to reach to the final core...

  5. Radiation intensification of the reactor pressure vessels recovery by low temperature heat treatment (wet annealing)

    Science.gov (United States)

    Krasikov, E.

    2015-04-01

    As a main barrier against radioactivity outlet reactor pressure vessel (RPV) is a key component in terms of NPP safety. Therefore present-day demands in RPV reliability enhance have to be met by all possible actions for RPV in-service embrittlement mitigation. Annealing treatment is known to be the effective measure to restore the RPV metal properties deteriorated by neutron irradiation. There are two approaches to annealing. The first one is so-called «dry» high temperature (∼475°C) annealing. It allows obtaining practically complete recovery, but requires the removal of the reactor core and internals. External heat source (furnace) is required to carry out RPV heat treatment. The alternative approach is to anneal RPV at a maximum coolant temperature which can be obtained using the reactor core or primary circuit pumps while operating within the RPV design limits. This low temperature «wet» annealing, although it cannot be expected to produce complete recovery, is more attractive from the practical point of view especially in cases when the removal of the internals is impossible.

  6. Radiation intensification of the reactor pressure vessels recovery by low temperature heat treatment (wet annealing)

    International Nuclear Information System (INIS)

    Krasikov, E

    2015-01-01

    As a main barrier against radioactivity outlet reactor pressure vessel (RPV) is a key component in terms of NPP safety. Therefore present-day demands in RPV reliability enhance have to be met by all possible actions for RPV in-service embrittlement mitigation. Annealing treatment is known to be the effective measure to restore the RPV metal properties deteriorated by neutron irradiation.There are two approaches to annealing. The first one is so-called «dry» high temperature (∼475°C) annealing. It allows obtaining practically complete recovery, but requires the removal of the reactor core and internals. External heat source (furnace) is required to carry out RPV heat treatment.The alternative approach is to anneal RPV at a maximum coolant temperature which can be obtained using the reactor core or primary circuit pumps while operating within the RPV design limits. This low temperature «wet» annealing, although it cannot be expected to produce complete recovery, is more attractive from the practical point of view especially in cases when the removal of the internals is impossible. (paper)

  7. Efficient reduction of graphene oxide film by low temperature heat treatment and its effect on electrical conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xuebing; Chen, Zheng [Jingdezhen Ceramic Institute, Jingdezhen (China). Key Lab. of Inorganic Membrane; Yu, Yun [Shanghai Institute of Ceramics, Shanghai (China). Key Lab. of Inorganic Coating Materials; Zhang, Xiaozhen; Wang, Yongqing; Zhou, Jianer [Jingdezhen Ceramic Institute, Jingdezhen (China). Dept. of Materials Engineering

    2018-03-01

    Graphene-based conductive films have already attracted great attention due to their unique and outstanding physical properties. In this work, in order to develop a novel, effective method to produce these films with good electrical conductivity, a simple and green method is reported to rapidly and effectively reduce graphene oxide film using a low temperature heat treatment. The reduction of graphene oxide film is verified by XRD, FT-IR and Raman spectroscopy. Compared with graphene oxide film, the obtained reduced graphene oxide film has better electrical conductivity and its sheet resistance decreases from 25.3 kΩ x sq{sup -1} to 3.3 kΩ x sq{sup -1} after the heat treatment from 160 to 230 C. The mechanism of thermal reduction of the graphene oxide film mainly results from the removal of the oxygen-containing functional groups and the structural changes. All these results indicate that the low temperature heat treatment is a suitable and effective method for the reduction of graphene oxide film.

  8. Low temperature heat treatments of AA5754-Ti6Al4V dissimilar laser welds: Microstructure evolution and mechanical properties

    Science.gov (United States)

    Leo, P.; D'Ostuni, S.; Casalino, G.

    2018-03-01

    This paper presents the effects of the post welding heat treatments (PWHT) performed at 350 °C and 450 °C on the microstructure evolution and mechanical properties of AA5754 and Ti6Al4V dissimilar laser welds. The microstructure and tensile properties of the welds before and after low temperature treatment were analyzed. The off-set welding technique was applied to limit the formation of brittle intermetallic compounds during the welding process. The laser beam was directed onto the titanium side at a small distance from the aluminum edge. The keyhole formed and the full penetration was reached in the titanium side of the weld. Thereafter, the aluminum side melted as the heat that formed the keyhole transferred from the titanium fused zone. Two different energy lines (32 J/mm and 76 J/mm) were used. In this manner, a fused and a heat affected zones was revealed on both sides of the weld. Several intermetallic compounds formed in the intermetallic layer between the two metals. The thickness and the composition of the intermetallic layer depended on the welding parameters and the post welding heat treatment. The hardness and tensile properties of the welds before and after the post welding heat treatment were measured and analyzed.

  9. Low temperature thermal conductivity of amorphous (Fe, Ni, Co) (P, B, Si) alloys and their change by heat treatment

    International Nuclear Information System (INIS)

    Pompe, G.; Gaafar, M.; Buettner, P.; Francke, T.

    1983-01-01

    The thermal conductivity of amorphous metallic alloys (Fe, Ni, Co)/sub 1-x/ (B, P, Si)/sub x/ is measured in the temperature range 2 to 100 K in the as-produced and heat-treated states. By taking into account the results of Matey and Anderson the influence of the nature of the metalloid and the number of metallic components can be discussed. The change of the thermal conductivity due to a structural relaxation caused by a heat treatment is very different. In the whole range of temperature a rise of the phonon thermal conductivity of the Fe-Co-B alloy is obtained, whereas no change is observed for the Fe-B alloy. At low temperature ( 80 B 20 is investigated. (author)

  10. Exchange bias in sputtered FeNi/FeMn systems: Effect of short low-temperature heat treatments

    Energy Technology Data Exchange (ETDEWEB)

    Savin, Peter, E-mail: peter.savin@urfu.ru [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Guzmán, Jorge [Instituto de Ciencia de Materiales de Madrid-CSIC, 28049 Madrid (Spain); Lepalovskij, Vladimir [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Svalov, Andrey; Kurlyandskaya, Galina [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Departamento de Electricidad y Electrónica, Universidad del País Vasco (UPV/EHU), 48940 Leioa, Vizcaya (Spain); Asenjo, Agustina [Instituto de Ciencia de Materiales de Madrid-CSIC, 28049 Madrid (Spain); Vas’kovskiy, Vladimir [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Vazquez, Manuel [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Instituto de Ciencia de Materiales de Madrid-CSIC, 28049 Madrid (Spain)

    2016-03-15

    Short (5 min) post-deposition thermal treatments under magnetic field at low temperature (up to 200 °C) performed in exchange-coupled FeNi(40 nm)/FeMn(20 nm) bilayer thin films prepared by magnetron sputtering are shown to be effective to significantly modify their exchange field (from around 40 Oe down to 27 Oe) between FeNi and FeMn layers. A similar exchange field decrease was observed for the first deposited FeNi layer of the FeNi(40 nm)/FeMn(20 nm)/FeNi(40 nm) trilayer films after the same thermal treatments. The exchange field value for the second FeNi layer was not substantially changed. The X-ray diffraction patterns indicates that such a heat treatment has no effect on the grain size and crystalline texture of the films, while atomic force microscope studies reveal an increase of the surface roughness after the treatment which is more noticeable in the case of the trilayer film. Analysis of the experimental results leads us to conclude that the variations of the exchange field after heat treatment are likely caused by a modification of interfacial roughness and/or interfacial magnetic structure, but unlikely by the changes in the microstructure and/or changes of composition of the antiferromagnetic FeMn layer. - Highlights: • FeNi/FeMn bilayers and FeNi/FeMn/FeNi trilayers were prepared by magnetron sputtering. • Post-deposition heat treatments at the temperatures below 200 °C during 5 min were made. • Annealing reduces the exchange field for the first FeNi layer in trilayers. • The exchange field value for the second FeNi layer was not substantially changed. • Exchange field changes are most likely caused by a modification of interface roughness.

  11. The study on the effect of low-temperature heat treatment on tissue dehydration fish pond

    Directory of Open Access Journals (Sweden)

    N. S. Rodionova

    2013-01-01

    Full Text Available The paper is studied thermo-moisture treatment of carp on the provisional application of vacuum packaging. The degree of hydration of the carp meat tissues equally depends on the prepackaging, as well as the characteristics of the fluid in the chamber system. With increasing temperature the degree of hydration of meat carp tissue decreases with the reduction of the difference in its numerical values of packed and unpacked samples. Obtained a graph of depence dependence of the speed of carp meat tissue dehydration of the processing temperature. Revealed that the presence of plastic packaging, as well as wetting fluid help reduce the dehydration speed of carp meat tissues.

  12. Measurement of low-temperature specific heat

    International Nuclear Information System (INIS)

    Stewart, G.R.

    1983-01-01

    The measurement of low-temperature specific heat (LTSH) (0.1 K< T<60 K) has seen a number of breakthroughs both in design concepts and instrumentation in the last 15 years: particularly in small sample calorimetry. This review attempts to provide an overview of both large and small sample calorimetry techniques at temperatures below 60 K, with sufficient references to enable more detailed study. A comprehensive review is made of the most reliable measurements of the LTSH of 84 of the elements to illustrate briefly some of the problems of measurements and analysis, as well as to provide additional references. More detail is devoted to three special areas of low-temperature calorimetry that have seen rapid development recently: (1) measurement of the specific heat of highly radioactive samples, (2) measurement of the specific heat of materials in high magnetic fields (18 T), and (3) measurement of the specific heat of very small (100 μg) samples. The review ends with a brief discussion of the frontier research currently underway on microcalorimetry for nanogram sample weights

  13. Desalination by very low temperature nuclear heat

    International Nuclear Information System (INIS)

    Saari, Risto

    1977-01-01

    A new sea water desalination method has been developed: Nord-Aqua Vacuum Evaporation, which utilizes waste heat at a very low temperature. The requisite vacuum is obtained by the aid of a barometric column and siphon, and the dissolved air is removed from the vacuum by means of water flows. According to test results from a pilot plant, the process is operable if the waste heat exists at a temperature 7degC higher than ambient. The pumping energy which is then required is 9 kcal/kg, or 1.5% of the heat of vaporization of water. Calculations reveal that the method is economically considerably superior to conventional distilling methods. (author)

  14. Predicting outgrowth and inactivation of Clostridium perfringens in meat products during low temperature long time heat treatment

    DEFF Research Database (Denmark)

    Duan, Zhi; Hansen, Terese Holst; Hansen, Tina Beck

    2016-01-01

    With low temperature long time (LTLT) cooking it can take hours for meat to reach a final core temperature above 53 °C and germination followed by growth of Clostridium perfringens is a concern. Available and new growth data in meats including 154 lag times (tlag), 224 maximum specific growth rates...... (μmax) and 25 maximum population densities (Nmax) were used to developed a model to predict growth of C. perfringens during the coming-up time of LTLT cooking. New data were generate in 26 challenge tests with chicken (pH 6.8) and pork (pH 5.6) at two different slowly increasing temperature (SIT...... the SIT profiles. Similar results were found for non-heated and heated spores in chicken, whereas in pork C. perfringens 790-94 increased less than 1 log CFU/g. At 53 °C C. perfringens 790-94 was log-linearly inactivated. Observed and predicted concentrations of C. perfringens, at the time when 53 °C (log...

  15. Simple approach to carboxyl-rich materials through low-temperature heat treatment of hydrothermal carbon in air

    Energy Technology Data Exchange (ETDEWEB)

    Chen Zhen; Ma Lijian; Li Shuqiong; Geng Junxia; Song Qiang; Liu Jun; Wang Chunli; Wang Hang; Li Juan [College of Chemistry, Sichuan University, Key Laboratory of Radiation Physics and Technology (Sichuan University), Ministry of Education, Chengdu 610064 (China); Qin Zhi [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Li Shoujian, E-mail: sjli000616@scu.edu.cn [College of Chemistry, Sichuan University, Key Laboratory of Radiation Physics and Technology (Sichuan University), Ministry of Education, Chengdu 610064 (China)

    2011-08-01

    It was found that a large number of oxygen-containing functional groups (OFGs) could be created on the surface of hydrothermal carbon (HTC) by simply heating at lower temperature in air during the course of our preliminary experiments which focused on oxidation pre-treatment of pristine HTC for the purpose of grafting functionalization. Especially carboxyl groups on HTC would increase significantly, from 0.53 to 3.70 mmol/g after heat treatment at 300 deg. C. So, effects of heat-treatment on the OFGs on the carbon microsphere were deeply studied to confirm and explain the findings. Experiments involving different materials (HTC, activated carbon and glucose) were performed under varying conditions (heating temperature and time, in air or in Ar atmosphere). A reaction mechanism for newly generating carboxyl groups on HTC surface during heat-treatment process was supposed based on the results from the sample characterization using Boehm titrations, infrared spectra, X-ray photoelectron spectroscopy, energy dispersive spectrometry and elemental analysis. In addition, the as heat-treated product has excellent sorption capability for Pb{sup 2+} and Cd{sup 2+} ions.

  16. Preventing hydrogen-including cracking after welding of pressure vessel steels by use of low temperature postweld heat treatments

    International Nuclear Information System (INIS)

    Schulze, G.

    1977-01-01

    Based on extensive literature evaluations and an experimental programme, the possibilities and limits of avoiding hydrogen-induced cracking in welded joints through heat treatment are presented. The author refers to a report by J.S. Caplan and E. Landerman, published in 1976. (orig./IHOE) [de

  17. HEAT PUMP USING SUBSOIL WATERS AS LOW TEMPERATURE HEAT SOURCE

    Directory of Open Access Journals (Sweden)

    Denysova Alla

    2015-08-01

    Full Text Available One of the basic directions of perfection of heat supply systems is the tendency of transition to the low-temperature heating systems based on application of heat pump installations. We consider heat supply system with heat pump installations using subsoil waters. Numerical simulation of thermal processes in the elements of a single-stage and double-stage heat pump systems has been worked out. Values of depths of wells and their quantity, necessary for effective operation of the offered installations, and values of capacity of electric water pumps for subsoil waters unit are calculated. Capacity of compressor electric drive and coefficient of performance of heat pump for the conditions of the city of Odessa are presented.

  18. Measured Performance of a Low Temperature Air Source Heat Pump

    Energy Technology Data Exchange (ETDEWEB)

    R.K. Johnson

    2013-09-01

    A 4-ton Low Temperature Heat Pump (LTHP) manufactured by Hallowell International was installed in a residence near New Haven, Connecticut and monitored over two winters of operation. After attending to some significant service issues, the heat pump operated as designed. This report should be considered a review of the dual compressor “boosted heat pump” technology. The Low Temperature Heat Pump system operates with four increasing levels of capacity (heat output) as the outdoor temperature drops.

  19. Innovative system for delivery of low temperature district heating

    OpenAIRE

    Ianakiev, A; Cui, JM; Garbett, S; Filer, A

    2017-01-01

    An innovative low temperature district heating (LTDH) local network is developed in Nottingham, supported by the REMOURBAN project, part of the H2020 Smart City and Community Lighthouse scheme. It was proposed that a branch emanating from the return pipe of the existing district heating system in Nottingham would be created to use low temperature heating for the first time on such scale in the UK. The development is aimed to extract unused heat from existing district heating system and to mak...

  20. Effect of prolonged heat treatments at low temperature on shear force and cooking loss in cows and young bulls

    DEFF Research Database (Denmark)

    Christensen, L.; Andersen, L.; Løje, Hanne

    2011-01-01

    and cooking loss in semitendinosus from cows (4-6 years) and young bulls (12-14 months), representing 2 categories of beef with varying thermal strength of connective tissue. Vacuum packed muscle samples were heat treated at 53°C, 55°C, 58°C and 63°C in water baths for 2½, 7½ and 19½ h. Cooking loss...... 53°C to 55°C, or when increasing heating time from 2½ to 7½ h at 53°C. In semitendinosus from cows shear force decreased significantly with increasing temperature, and with increasing heating time from 2½ to 19½ h at 55°C and 63°C. Cooking loss increased with increasing heating temperature in both...

  1. Industrial waste heat utilization for low temperature district heating

    International Nuclear Information System (INIS)

    Fang, Hao; Xia, Jianjun; Zhu, Kan; Su, Yingbo; Jiang, Yi

    2013-01-01

    Large quantities of low grade waste heat are discharged into the environment, mostly via water evaporation, during industrial processes. Putting this industrial waste heat to productive use can reduce fossil fuel usage as well as CO 2 emissions and water dissipation. The purpose of this paper is to propose a holistic approach to the integrated and efficient utilization of low-grade industrial waste heat. Recovering industrial waste heat for use in district heating (DH) can increase the efficiency of the industrial sector and the DH system, in a cost-efficient way defined by the index of investment vs. carbon reduction (ICR). Furthermore, low temperature DH network greatly benefits the recovery rate of industrial waste heat. Based on data analysis and in-situ investigations, this paper discusses the potential for the implementation of such an approach in northern China, where conventional heat sources for DH are insufficient. The universal design approach to industrial-waste-heat based DH is proposed. Through a demonstration project, this approach is introduced in detail. This study finds three advantages to this approach: (1) improvement of the thermal energy efficiency of industrial factories; (2) more cost-efficient than the traditional heating mode; and (3) CO 2 and pollutant emission reduction as well as water conservation. -- Highlights: •We review situation of industrial waste heat recovery with a global perspective. •We present a way to analyze the potential to utilize industrial waste heat for DH. •Northern China has huge potential for using low-grade industrial waste heat for DH. •A demonstration project is introduced using the universal approach we propose. •It proves huge benefits for factories, heat-supply companies and the society

  2. Development of CuInTe{sub 2} thin film solar cells by electrochemical route with low temperature (80 °C) heat treatment procedure

    Energy Technology Data Exchange (ETDEWEB)

    Lakhe, Manorama [Electrochemical Laboratory, Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Mahapatra, S.K. [Department of Applied Physics, Birla Institute of Technology, Mesra, Ranchi 835215 (India); Chaure, Nandu B., E-mail: n.chaure@physics.unipune.ac.in [Electrochemical Laboratory, Department of Physics, Savitribai Phule Pune University, Pune 411007 (India)

    2016-02-15

    Graphical abstract: Dark and illuminated J–V characteristic for Cell B, successively heat treated at 80 °C for 60 min and corresponding dV/d(J + J{sub L}) versus 1/(J + J{sub L}) plot. Efficiency, η = 3.8%, series resistance, R{sub s} = 43 Ω and ideality factor, n = 1.9 are measured for Cell B. - Highlights: • Temperature, 80 °C is sufficient to produce highly crystalline CuInTe{sub 2} thin films. • Stoichiometric, uniform and well adherent thin films of CuInTe{sub 2} were electrodeposited. • 3.8% efficiency was measured for a cell prepared by successive heat treatment at 80 °C. • ‘R{sub s}’ and ‘n’ investigated for Cell A and B were 47, 43 Ω and 2.0 and 1.9, respectively. - Abstract: The effect of successive low-temperature heat treatment on the properties of electrodeposited CuInTe{sub 2} (CIT) thin films is investigated. The electrodeposition potential, −0.8 V versus Ag/AgCl was optimized by cyclic voltammetry onto CdS coated Fluorine doped tin oxide substrate. The samples were successively heat treated at 80 °C for 5, 30 and 60 min in an air ambient. The structural, morphological, compositional, electrical and optoelectronic properties were studied using XRD, Raman spectroscopy, SEM, FESEM, EDS, Current–Voltage and Capacitance–Voltage measurements. As-prepared CIT film exhibited amorphous nature, whereas the systematic development in the crystallinity was observed in successively heat treated samples. Compact, densely packed, globular surface morphology was observed. The Cu/In ratio was found to be increased systematically from 0.60 to 0.82 with heat treatment duration. The solar cell devices successively heat treated at 80 °C for 30 and 60 min measured an efficiency (η), 3.4% and 3.8%, respectively.

  3. Challenges in Smart Low-Temperature District Heating Development

    DEFF Research Database (Denmark)

    Li, Hongwei; Wang, Stephen Jia

    2014-01-01

    Previous research and development shows that low temperature district heating (LTDH) system is economic feasible for low energy buildings and buildings at sparse areas. Coupling with reduced network temperature and well-designed district heating (DH) networks, LTDH can reduce network heat loss by...

  4. Energy and exergy analysis of low temperature district heating network

    DEFF Research Database (Denmark)

    Li, Hongwei; Svendsen, Svend

    2012-01-01

    is designed to supply heating for 30 low energy detached residential houses. The network operational supply/return temperature is set as 55 °C/25 °C, which is in line with a pilot project carried out in Denmark. Two types of in-house substations are analyzed to supply the consumer domestic hot water demand...... energy/exergy losses and increase the quality match between the consumer heating demand and the district heating supply.......Low temperature district heating with reduced network supply and return temperature provides better match of the low quality building heating demand and the low quality heating supply from waste heat or renewable energy. In this paper, a hypothetical low temperature district heating network...

  5. Low-temperature heating systems and public administration

    Energy Technology Data Exchange (ETDEWEB)

    Boerner, H

    1981-06-01

    The even temperature distribution and comfortable climate in rooms heated by low-temperature heating systems is mostly due to one of the preconditions of this type of heating system namely, efficient thermal insulation of the rooms. Thermal insulation is already required as part of the pertinent legal regulations but it is also in the interest of the builder-owner as it will, in the long run, greatly reduce the heating cost.

  6. Energy and exergy analysis of low temperature district heating network

    International Nuclear Information System (INIS)

    Li, Hongwei; Svendsen, Svend

    2012-01-01

    Low temperature district heating with reduced network supply and return temperature provides better match of the low quality building heating demand and the low quality heating supply from waste heat or renewable energy. In this paper, a hypothetical low temperature district heating network is designed to supply heating for 30 low energy detached residential houses. The network operational supply/return temperature is set as 55 °C/25 °C, which is in line with a pilot project carried out in Denmark. Two types of in-house substations are analyzed to supply the consumer domestic hot water demand. The space heating demand is supplied through floor heating in the bathroom and low temperature radiators in the rest of rooms. The network thermal and hydraulic conditions are simulated under steady state. A district heating network design and simulation code is developed to incorporate the network optimization procedure and the network simultaneous factor. Through the simulation, the overall system energy and exergy efficiencies are calculated and the exergy losses for the major district heating system components are identified. Based on the results, suggestions are given to further reduce the system energy/exergy losses and increase the quality match between the consumer heating demand and the district heating supply. -- Highlights: ► Exergy and energy analysis for low and medium temperature district heating systems. ► Different district heating network dimensioning methods are analyzed. ► Major exergy losses are identified in the district heating network and the in-house substations. ► Advantages to apply low temperature district heating are highlighted through exergy analysis. ► The influence of thermal by-pass on system exergy/energy performance is analyzed.

  7. Heat Transfer and Cooling Techniques at Low Temperature

    CERN Document Server

    Baudouy, B

    2014-07-17

    The first part of this chapter gives an introduction to heat transfer and cooling techniques at low temperature. We review the fundamental laws of heat transfer (conduction, convection and radiation) and give useful data specific to cryogenic conditions (thermal contact resistance, total emissivity of materials and heat transfer correlation in forced or boiling flow for example) used in the design of cooling systems. In the second part, we review the main cooling techniques at low temperature, with or without cryogen, from the simplest ones (bath cooling) to the ones involving the use of cryocoolers without forgetting the cooling flow techniques.

  8. Heat Transfer and Cooling Techniques at Low Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Baudouy, B [Saclay (France)

    2014-07-01

    The first part of this chapter gives an introduction to heat transfer and cooling techniques at low temperature. We review the fundamental laws of heat transfer (conduction, convection and radiation) and give useful data specific to cryogenic conditions (thermal contact resistance, total emissivity of materials and heat transfer correlation in forced or boiling flow for example) used in the design of cooling systems. In the second part, we review the main cooling techniques at low temperature, with or without cryogen, from the simplest ones (bath cooling) to the ones involving the use of cryocoolers without forgetting the cooling flow techniques.

  9. Low Temperature District Heating for Future Energy Systems

    DEFF Research Database (Denmark)

    Schmidt, Dietrich; Kallert, Anna; Blesl, Markus

    2017-01-01

    of the building stock. Low temperature district heating (LTDH) can contribute significantly to a more efficient use of energy resources as well as better integration of renewable energy (e.g. geothermal or solar heat), and surplus heat (e.g. industrial waste heat) into the heating sector. LTDH offers prospects......The building sector is responsible for more than one third of the final energy consumption of societies and produces the largest amount of greenhouse gas emissions of all sectors. This is due to the utilisation of combustion processes of mainly fossil fuels to satisfy the heating demand...... for both the demand side (community building structure) and the supply side (network properties or energy sources). Especially in connection with buildings that demand only low temperatures for space heating. The utilisation of lower temperatures reduces losses in pipelines and can increase the overall...

  10. Innovative system for delivery of low temperature district heating

    Directory of Open Access Journals (Sweden)

    Anton Ivanov Ianakiev

    2017-01-01

    Full Text Available An innovative Low Temperature District Heating (LTDH local network is developed in Nottingham, supported by REMOURBAN project, part of the H2020 Smart City and Community Lighthouse scheme. It was proposed that a branch emanating from the return pipe of the of the existing district heating system in Nottingham would be created to use low temperature heating for the first time in UK. The development is aimed to extract wasted (unused heat from existing district heating system and make it more efficient and profitable. Four maisonette blocks of 94 low-raised flats, at Nottingham demo site of the REMOURBAN project will be connected to this new LTDH system. The scheme will provide a primary supply of heat and hot water at approximately 50oC to 60oC. Innovated solutions have been put forward to overcome certain barriers, such as legionella related risks and peak loads during extreme heating seasons and occasional maintenance.

  11. Low Temperature District Heating for Future Energy Systems

    DEFF Research Database (Denmark)

    Ford, Rufus; Pietruschka, Dirk; Sipilä, Kari

    participants being VTT Technical Research Centre of Finland (VTT), Technical University of Denmark (DTU), Norwegian University of Science and Technology (NTNU), Stuttgart Technology University of Applied Sciences (HFT) and SSE Enterprise in United Kingdom. The demonstration cases described in the report......This report titled “Case studies and demonstrations” is the subtask D report of the IEA DHC|CHP Annex TS1 project “Low Temperature District Heating for Future Energy Systems” carried out between 2013 and 2016. The project was led by Fraunhofer Institute for Building Physics (IBP) with the other...... include examples on low temperature district heating systems, solar heating in a district heating system, heat pump based heat supply and energy storages for both peak load management and for seasonal heat storage. Some demonstrations have been implemented while others are at planning phase...

  12. Exergy and Energy Analysis of Low Temperature District Heating Network

    DEFF Research Database (Denmark)

    Li, Hongwei; Svendsen, Svend

    is in line with a pilot project that is carrying out in Denmark with network supply/return temperature at 55oC/25 oC. The consumer domestic hot water (DHW) demand is supplied with a special designed district heating (DH) storage tank. The space heating (SH) demand is supplied with a low temperature radiator......Low temperature district heating (LTDH) with reduced network supply and return temperature provides better match of the low quality building thermal demand and the low quality waste heat supply. In this paper, an exemplary LTDH network was designed for 30 low energy demand residential houses, which....... The network thermal and hydraulic conditions were simulated under steady state with an in-house district heating network design and simulation code. Through simulation, the overall system energetic and exergetic efficiencies were calculated and the exergy losses for the major district heating system...

  13. Low temperature specific heat anomalies in melanins and tumor melanosomes

    Energy Technology Data Exchange (ETDEWEB)

    Mizutani, U [Carnegie--Mellon Univ., Pittsburgh; Massalski, T B; McGinness, J E; Corry, P M

    1976-02-12

    Human malignant melanoma cells obtained at autopsy were used. Data indicate that melanins exhibit a large linear term (50-200 erg g/sup -1/K/sup -2/) and that they seem to undergo a phase transition as indicated by the heat capacity near 1.9/sup 0/K. A table is presented to show low temperature specific heat data for melanin samples. The measurements include two anomalies, a transition and an unusually high linear contribution. (HLW)

  14. The future of the low temperature district heating reactor

    International Nuclear Information System (INIS)

    Lu Yingzhong; Wang Dazhong; Ma Changwen; Dong Duo; Tian Jiafu.

    1984-01-01

    In this paper, the role, development and situation of the low temperature district heating reactor (LTDHR) are briefly summarized. There are four types of LTDHR. They are PWR, reactor with boiling in the chimney, organic reactor and swimming pool reactor. The features of these reactors are introduced. The situation and role of the LTDHR in the future of the energy system are also discussed. The experiment on nuclear district heating with the swimming pool reactor in Qinghua Univ. is described briefly. (Author)

  15. Mapping of low temperature heat sources in Denmark

    DEFF Research Database (Denmark)

    Bühler, Fabian; Holm, Fridolin Müller; Huang, Baijia

    2015-01-01

    heat. The total accessible waste heat potential is found to be approximately 266 PJ per year with 58 % of it below 100 °C. In the natural heat category, temperatures below 20 °C originate from ambient air, sea water and shallow geothermal energy, and temperatures up to 100 °C are found for solar...... and deep geothermal energy. The theoretical solar thermal potential alone would be above 500 PJ per year. For the development of advanced thermodynamic cycles for the integration of heat sources in the Danish energy system, several areas of interest are determined. In the maritime transport sector a high......Low temperature heat sources are available in many applications, ranging from waste heat from industrial processes and buildings to geothermal and solar heat sources. Technical advancements, such as heat pumps with novel cycle design and multi-component working fluids, make the utilisation of many...

  16. STUDY ON THE EFFECT OF LOW-TEMPERATURE HEAT TREATMENT ON THE SHELF LIFE OF SEMI-FINISHED PRODUCTS MADE FROM CARP

    Directory of Open Access Journals (Sweden)

    N. S. Rodionova

    2014-01-01

    Full Text Available Summary. Currently, the development of the catering industry due to improved heat cooking processes raw materials. One of these areas is the use of low temperature vapor cooking food pre-packed in the vacuum heat-resistant polymer film. This processing method allows to maintain vitamins, proteins, carbohydrates, fats, macro- and micronutrients raw unchanged and prevents food from undesirable organoleptic changes occurring in the traditional thermal processing, preserving attractive consumer product quality and hygienic safety guaranteed by increasing the period storage. Object of study - carp fillet, which is the source of complete protein and the spectrum of macro- and micronutrients. The article studies the shelf life of semi-finished products made from carp, treated with different modes of low-temperature thermo - humid cooking with the use of vacuum packaging. The authors found that during storage all samples carp decrease the mass fraction of the amino acids, and as a result, the mass fraction of the total protein in the samples. However, in the packaged samples treated with humidified coolant decrease the mass fraction of amino acids occurs less rapidly, indicating a better preservation of the amino acid content in the samples and hence maintaining bioavailability intermediates. Provisional vacuum packaging increases duration of the retention period.

  17. Power generation from low-temperature heat source

    Energy Technology Data Exchange (ETDEWEB)

    Lakew, Amlaku Abie

    2012-07-01

    The potential of low-temperature heat sources for power production has been discussed for decades. The diversity and availability of low-temperature heat sources makes it interesting for power production. The thermodynamic power cycle is one of the promising technologies to produce electricity from low-temperature heat sources. There are different working fluids to be used in a thermodynamic power cycle. Working fluid selection is essential for the performance of the power cycle. Over the last years, different working fluid screening criteria have been used. In broad speaking the screening criteria can be grouped as thermodynamic performance, component size requirement, economic performance, safety and environmental impact. Screening of working fluids at different heat source temperatures (80-200 Celsius degrees) using thermodynamic performance (power output and exergy efficiency) and component size (heat exchanger and turbine) is investigated. It is found that the 'best' working fluid depends on the criteria used and heat source temperature level. Transcritical power cycles using carbon dioxide as a working fluid is studied to produce power at 100 Celsius degrees. Carbon dioxide is an environmentally friendly refrigerant. The global warming potential of carbon dioxide is 1. Furthermore, because of its low critical temperature (31 Celsius degrees), carbon dioxide can operate in a transcritical power cycle for lower heat source temperatures. A transcritical configuration avoids the problem of pinching which otherwise would happened in subcritical power cycle. In the process, better temperature matching is achieved and more heat is extracted. Thermodynamic analysis of transcritical cycle is performed; it is found that there is an optimal operating pressure for highest net power output. The pump work is a sizable fraction of the work produced by the turbine. The effect of efficiency deterioration of the pump and the turbine is compared. When the

  18. Measured Performance of a Low Temperature Air Source Heat Pump

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R. K. [Johnson Research LLC, Pueblo West, CO (United States)

    2013-09-01

    A 4-ton Low Temperature Heat Pump (LTHP) manufactured by Hallowell International was installed in a residence near New Haven, Connecticut and monitored over two winters of operation. After attending to some significant service issues, the heat pump operated as designed. This report should be considered a review of the dual compressor 'boosted heat pump' technology. The Low Temperature Heat Pumpsystem operates with four increasing levels of capacity (heat output) as the outdoor temperature drops. The system was shown to select capacity correctly, supplying the appropriate amount of heat to the house across the full range of outdoor temperatures. The system's Coefficient of Performance (Seasonal COP, or SCOP) over two entire winters was calculated, based on measured data, to be 3.29over the first winter and 2.68 over the second winter. A second seasonal efficiency calculation by a different method yielded a SCOP of 2.78 for the first winter and 2.83 for the second winter. This second seasonal efficiency calculation was determined by comparing measured heat pump energy use to the in situ energy use with resistance heat alone. This method is the ratio of the slopes of thedaily energy use load lines.

  19. Potential of low-temperature nuclear heat applications

    International Nuclear Information System (INIS)

    1986-12-01

    At present, more than one third of the fossil fuel currently used is being consumed to produce space heating and to meet industrial needs in many countries of the world. Imported oil still represents a large portion of this fossil fuel and despite its present relatively low price future market evolutions with consequent upward cost revisions cannot be excluded. Thus the displacement of the fossil fuel by cheaper low-temperature heat produced in nuclear power plants is a matter which deserves careful consideration. Technico-economic studies in many countries have shown that the use of nuclear heat is fully competitive with most of fossil-fuelled plants, the higher investment costs being offset by lower production cost. Another point in favour of heat generation by nuclear source is its indisputable advantage in terms of benefits to the environment. The IAEA activity plans for 1985-86 concentrate on information exchange with specific emphasis on the design criteria, operating experience, safety requirements and specifications of heat-only reactors, co-generation plants and existing power plants backfitted for additional heat applications. The information gained up to 1985 was discussed during the Advisory Group Meeting on the Potential of Low-Temperature Nuclear Heat Applications held in the Federal Institute for Reactor Research, Wuerenlingen, Switzerland in September 1985 and, is included in the present Technical Document

  20. Utilization of low temperature heat for environmentally friendly electricity production

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Elmegaard, Brian; Haglind, Fredrik

    2014-01-01

    the benefits of using mixtures compared to pure fluids as working fluids in organic Rankine cycles. In order to do so, thermodynamic and economic analyses are carried out, first on an overall cycle level, and next on component level including detailed modelling of heat exchangers, pumps and expanders involving...... project collaborators with expertise in these areas. In addition to this, novel innovative cycle layouts are developed with the aim of increasing the economic feasibility of utilizing low temperature heat. As an example, this can be achieved by implementing separators in the power cycle to create optimal...

  1. Optimization criteria for low temperature waste heat utilization

    International Nuclear Information System (INIS)

    Kranebitter, F.

    1977-01-01

    A special case in this field is the utilization of very low temperature waste heat. The temperature level under consideration in this paper is in the range between the body temperature of human beings and their environment. The waste heat from power generation and industrial processes is also considered. Thermal energy conversion will be mainly accomplished by heat cycles where discharged waste heat is reverse proportional to the upper cycle temperature. Limiting this upper cycle temperature by technological reasons the optimization of the heat cycle will depend on the nature of the cycle itself and specially on the temperature selected for the heat discharge. The waste heat discharge is typical for the different kinds of heat cycles and the paper presents the four most important of them. Feasible heat transfer methods and their economic evaluations are discussed and the distillation processes will be the basis for further considerations. The waste heat utilization for distillation purposes could be realized by three different cycles, the open cycle, the closed cycle and the multy cycle. Resulting problems as deaeration of large water streams and removal of the dissolved gases and their solutions are also discussed. (M.S.)

  2. Small reactors for low-temperature nuclear heat applications

    International Nuclear Information System (INIS)

    1988-06-01

    In accordance with the Member States' calls for information exchange in the field of nuclear heat application (NHA) two IAEA meetings were organized already in 1976 and 1977. After this ''promising period'', the development of relevant programmes in IAEA Member States was slowed down and therefore only after several years interruption a new Technical Committee Meeting with a Workshop was organized in late 1983, to review the status of NHA, after a few new specific plans appeared in some IAEA Member States in the early 1980's for the use of heat from existing or constructed NPPs and for developing nuclear heating plants (NHP). In June 1987 an Advisory Group Meeting was convened in Winnipeg, Canada, to discuss and formulate a state-of-the-art review on ''Small Reactors for Low Temperature Nuclear Heat Application''. Information on this subject gained up to 1987 in the Member States whose experts attended this meeting is embodied in the present Technical Report. Figs and tabs

  3. Sea water desalination utilizing waste heat by low temperature evaporation

    International Nuclear Information System (INIS)

    Raha, A.; Srivastava, A.; Rao, I.S.; Majumdar, M.; Srivastava, V.K.; Tewari, P.K.

    2007-01-01

    Economics of a process is controlled by management of energy and resources. Fresh water has become most valued resource in industries. Desalination is a process by which fresh water resource is generated from sea water or brackish water, but it is an energy intensive process. The energy cost contributes around 25-40% to the total cost of the desalted water. Utilization of waste heat from industrial streams is one of the ecofriendly ways to produce low cost desalted water. Keeping this in mind Low Temperature Evaporation (LTE) desalination technology utilizing low quality waste heat in the form of hot water (as low as 50 deg C) or low pressure steam (0.13 bar) has been developed for offshore and land based applications to produce high purity water (conductivity < 2μS/cm) from sea water. The probability of the scale formation is practically eliminated by operating it at low temperature and controlling the brine concentration. It also does not require elaborate chemical pretreatment of sea water except chlorination, so it has no environmental impact. LTE technology has found major applications in nuclear reactors where large quantity of low quality waste heat is available to produce high quality desalted water for make up water requirement replacing conventional ion exchange process. Successful continuous operation of 30 Te/day LTE desalination plant utilizing waste heat from nuclear research reactor has demonstrated the safety, reliability, extreme plant availability and economics of nuclear desalination by LTE technology. It is also proposed to utilize waste heat from Main Heat Transport (MHT) purification circuit of Advanced Heavy Water Reactor (AHWR) to produce about 250 Te/ day high quality desalinated water by Low Temperature Evaporation (LTE) process for the reactor make up and plant utilization. Recently we have commissioned a 50 Te/day 2-effect low temperature desalination plant with cooling tower where the specific energy and cooling water requirement are

  4. Containment for low temperature district nuclear-heating reactor

    International Nuclear Information System (INIS)

    He Shuyan; Dong Duo

    1992-03-01

    Integral arrangement is adopted for Low Temperature District Nuclear-heating Reactor. Primary heat exchangers, control rod drives and spent fuel elements are put in the reactor pressure vessel together with reactor core. Primary coolant flows through reactor core and primary heat exchangers in natural circulation. Primary coolant pipes penetrating the wall of reactor pressure vessel are all of small diameters. The reactor vessel constitutes the main part of pressure boundary of primary coolant. Therefore the small sized metallic containment closed to the wall of reactor vessel can be used for the reactor. Design principles and functions of the containment are as same as the containment for PWR. But the adoption of small sized containment brings about some benefits such as short period of manufacturing, relatively low cost, and easy for sealing. Loss of primary coolant accident would not be happened during the rupture accident of primary coolant pressure boundary inside the containment owing to its intrinsic safety

  5. Optimal usage of low temperature heat sources to supply district heating by heat pumps

    DEFF Research Database (Denmark)

    Pieper, Henrik; Ommen, Torben Schmidt; Markussen, Wiebke Brix

    2017-01-01

    This paper presents a theoretical study on the optimal usage of different low temperature heat sources to supply district heating by heat pumps. The study is based on data for the Copenhagen region. The heat sources were prioritized based on the coefficient of performance calculated for each hour...... and the covered demand of each heat source as well as required peak unit capacity. The results showed that heat pumps using different heat sources yield better performance than a heat pump based on a single one. The performance was influenced by the composition of the different heat sources. It was found that 78......% groundwater, 22% seawater and 0% air resulted in highest COP of 3.33 for the given heat demand. Furthermore, the implementation of rule based short term storage made peak units redundant. The variation in base load capacity showed that heat pumps utilizing the analyzed heat sources could perform very...

  6. Integration of space heating and hot water supply in low temperature district heating

    DEFF Research Database (Denmark)

    Elmegaard, Brian; Ommen, Torben Schmidt; Markussen, Michael

    2016-01-01

    District heating may supply many consumers efficiently, but the heat loss from the pipes to the ground is a challenge. The heat loss may be lowered by decreasing the network temperatures for which reason low temperature networks are proposed for future district heating. The heating demand...... of the consumers involves both domestic hot water and space heating. Space heating may be provided at low temperature in low energy buildings. Domestic hot water, however, needs sufficient temperatures to avoid growth of legionella. If the network temperature is below the demand temperature, supplementary heating...... is required by the consumer. We study conventional district heating at different temperatures and compare the energy and exergetic efficiency and annual heating cost to solutions that utilize electricity for supplementary heating of domestic hot water in low temperature district heating. This includes direct...

  7. Combined cycle power plant with integrated low temperature heat (LOTHECO)

    International Nuclear Information System (INIS)

    Kakaras, E.; Doukelis, A.; Leithner, R.; Aronis, N.

    2004-01-01

    The major driver to enhance the efficiency of the simple gas turbine cycle has been the increase in process conditions through advancements in materials and cooling methods. Thermodynamic cycle developments or cycle integration are among the possible ways to further enhance performance. The current paper presents the possibilities and advantages from the LOTHECO natural gas-fired combined cycle concept. In the LOTHECO cycle, low-temperature waste heat or solar heat is used for the evaporation of injected water droplets in the compressed air entering the gas turbine's combustion chamber. Following a description of this innovative cycle, its advantages are demonstrated by comparison between different gas turbine power generation systems for small and large-scale applications, including thermodynamic and economic analysis. A commercial gas turbine (ALSTOM GT10C) has been selected and computed with the heat mass balance program ENBIPRO. The results from the energy analysis are presented and the features of each concept are discussed. In addition, the exergy analysis provides information on the irreversibilities of each process and suggested improvements. Finally, the economic analysis reveals that the combined cycle plant with a heavy-duty gas turbine is the most efficient and economic way to produce electricity at base load. However, on a smaller scale, innovative designs, such as the LOTHECO concept, are required to reach the same level of performance at feasible costs

  8. Low temperature heat capacity of scandium and alloys of scandium

    Energy Technology Data Exchange (ETDEWEB)

    Tsang, T. W.E.

    1977-12-01

    The heat capacity of three electrotransport purified scandium samples has been measured from 1 to 20/sup 0/K. The resultant electronic specific heat constant and Debye temperature are 10.337 +- 0.015 mJ/gm-atom K/sup 2/ and 346.7 +- 0.8/sup 0/K respectively, and these values are believed to be truly representative of intrinsic scandium. Alloying studies have also been carried out to investigate the band structure of scandium based on the rigid band model, with zirconium to raise the electron concentration and magnesium to lower it. The results are then compared to the theoretical band structure calculations. Low temperature heat capacity measurements have also been made on some dilute Sc-Fe alloys. An anomaly is observed in the C/T vs. T/sup 2/ plot, but the C vs. T curve shows no evidence of magnetic ordering down to 1/sup 0/K, and electrical resistance measurement from 4 to 0.3/sup 0/K also indicates that no magnetic ordering took place.

  9. Utilization of low-temperature heat sources for heat and power production

    DEFF Research Database (Denmark)

    Haglind, Fredrik; Elmegaard, Brian

    2014-01-01

    Low-temperature heat sources are available in many applications, ranging from waste heat from marine diesel engines, industries and refrigeration plants to biomass, geothermal and solar heat sources. There is a great potential for enhancing the utilization of these heat sources by novel...

  10. Conversion of medium and low temperature heat to power

    Science.gov (United States)

    Fischer, Johann; Wendland, Martin; Lai, Ngoc Anh

    2013-04-01

    Presently most electricity is produced in power plants which use high temperature heat supplied by coal, oil, gas or nuclear fission and Clausius-Rankine cycles (CRC) with water as working fluid (WF). On the other hand, geo-, solar-, ocean-, and biogenic-heat have medium and low temperatures. At these temperatures, however, the use of other WF and/or other cycles can yield higher efficiencies than those of the water-CRC. For an assessment of the efficiency we model systems which include the heat transfer to and from the WF and the cycle. Optimization criterion is the exergy efficiency defined as the ratio of the net power output to the incoming exergy flow of the heat carrier. First, for a better understanding we discuss some thermodynamic properties of the WFs: 1) the critical point parameters, 2) the shape of the vapour- liquid coexistence curve in the temperature vs entropy (T,s)-diagram which may be either bell-shaped or overhanging [1,2], and 3) the shape of sub- and supercritical isobars for pure fluids and fluid mixtures. Second, we show that the problems of a CRC with water at lower temperatures are 1) the shape of the T,s-diagram and 2) the exergy loss during heat transfer to the WF. The first problem can be overcome by using an organic working fluid in the CRC which then is called organic Rankine cycle (ORC). The second problem is reduced by supercritical organic Rankine cycles (sORC) [1,2], trilateral cycles (TLC) and the more general power-flash cycles (PFC) [2], and organic flash cycles (OFC) [3]. Next, selected results for systems with the above mentioned cycles will be presented. The heat carrier inlet temperatures THC range from 120°C to 350°C.The pure working fluids are water, refrigerants, alkanes, aromates and siloxanes and have to be selected to match with THC. It is found that TLC with water have the highest efficiencies but show very large volume flows at lower temperatures. Moreover, expansion machines for TLC and PFC are still under

  11. Fabrication and superconducting properties of a simple-structured jelly-roll Nb{sub 3}Al wire with low-temperature heat-treatment

    Energy Technology Data Exchange (ETDEWEB)

    Cui, L.J. [National Engineering Laboratory for Superconducting Materials (NELSM), Western Superconducting Technologies (WST) Co. Ltd., Xi’an 710018 (China); Yan, G., E-mail: gyan@c-wst.com [National Engineering Laboratory for Superconducting Materials (NELSM), Western Superconducting Technologies (WST) Co. Ltd., Xi’an 710018 (China); Pan, X.F. [National Engineering Laboratory for Superconducting Materials (NELSM), Western Superconducting Technologies (WST) Co. Ltd., Xi’an 710018 (China); Zhang, P.X. [National Engineering Laboratory for Superconducting Materials (NELSM), Western Superconducting Technologies (WST) Co. Ltd., Xi’an 710018 (China); Northwest Institute for Nonferrous Metal Research (NIN), Xi’an 710016 (China); Qi, M. [Northwest Institute for Nonferrous Metal Research (NIN), Xi’an 710016 (China); Liu, X.H.; Feng, Y. [National Engineering Laboratory for Superconducting Materials (NELSM), Western Superconducting Technologies (WST) Co. Ltd., Xi’an 710018 (China); Chen, Y.L.; Zhao, Y. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Superconductivity and New Energy R& D Center, Southwest Jiaotong University (SWJTU), Chengdu 610031 (China)

    2015-06-15

    Highlights: • Nb{sub 3}Al superconducting wires with Cu-matrix and different filament numbers were prepared by the jelly-roll method. • The length of 18-cores Nb{sub 3}Al superconducting wire reaches 100 m without any breakage and intermediate anneal. • This wire has the uniform filament-shapes and fine long-wire homogeneity. • This Nb{sub 3}Al long wire has the T{sub c} of 13.4 K and J{sub c} of 4.7 × 10{sup 4} A/cm{sup 2} at 4.2 K and 12 T. - Abstract: With extremely high critical current density (J{sub c}) and excellent strain tolerance, Nb{sub 3}Al superconductor is considered as an alternative to Nb{sub 3}Sn for application of high-field magnets. However, owing to their complex structure, Nb{sub 3}Al superconducting wires can hardly meet the requirement of engineering application at present. In this work, a novel simple-structured Nb{sub 3}Al superconducting wires with Cu-matrix and different filament numbers were prepared by the conventional jelly-roll method, as well as a heat-treatment of 800–850 °C for 20–50 h. The results show that a 18-filament superconducting wire with length longer than 100 m can be successfully prepared by this method, and also this Nb{sub 3}Al long wire has the T{sub c} of 13.4 K and J{sub c} of 4.7 × 10{sup 4} A/cm{sup 2} at 4.2 K and 12 T. These suggest that with further optimization, the simple-structured Nb{sub 3}Al superconducting wires are very promising to fabricate the km-grade long wires to meet the requirement of engineering application.

  12. Comparative technical-economic analysis of the low temperature heating systems

    International Nuclear Information System (INIS)

    Sharevski, Vasko; Sharevski, Milan

    1994-01-01

    A method for comparative technical-economic analysis between low temperature heating systems and heating systems with fossil fuel boiler plant, heat pump heating system and electrical heating systems is presented. The single and combined heating systems are analyzed. The technical-economic priority application of the heating system is determined according to the prices of the low temperature heat energy, fossil fuel heat energy, electrical energy, as well as to the coefficient of the annual use of the installed heating capacity, investment expenses, structure of the combined heating system and coefficient of performances of the heat pump. The combined heating system, composed with a low temperature heating subsystem, which is used to cover the base heat demands, and a oil boiler plant heating subsystem, for the top heat demands, have technical-economic justification and wide range of priority application, in comparison with single heating systems. (author)

  13. Performance of ultra low temperature district heating systems with utility plant and booster heat pumps

    DEFF Research Database (Denmark)

    Ommen, Torben Schmidt; Thorsen, Jan Eric; Markussen, Wiebke Brix

    2017-01-01

    The optimal integration of booster heat pumps in ultra low temperature district heating (ULTDH) was investigated and compared to the performance of low temperature district heating. Two possible heat production technologies for the DH networks were analysed, namely extraction combined heat...... temperature and the heat consumption profile. For reference conditions, the optimal return of ULTDH varies between 21 °C and 27 °C. When using a central HP to supply the DH system, the resulting coefficient of system performance (COSP) was in the range of 3.9 (-) to 4.7 (-) for equipment with realistic...... component efficiencies and effectiveness, when including the relevant parameters such as DH system pressure and heat losses. By using ULTDH with booster HPs, performance improvements of 12% for the reference calculations case were found, if the system was supplied by central HPs. Opposite results were found...

  14. Integration of Space Heating and Hot Water Supply in Low Temperature District Heating

    DEFF Research Database (Denmark)

    Elmegaard, Brian; Ommen, Torben Schmidt; Markussen, Michael

    2014-01-01

    pipes, where the water is at the highest temperature. The heat loss may be lowered by decreasing the temperatures in the network for which reason low temperature networks are proposed as a low loss solution for future district heating. However, the heating demand of the consumers involve both domestic......District heating makes it possible to provide heat for many consumers in an efficient manner. In particular, district heating based on combined heat and power production is highly efficient. One disadvantage of district heating is that there is a significant heat loss from the pipes...... to the surrounding ground. In larger networks involving both transmission and distribution systems, the heat loss is most significant from the distribution network. An estimate is that about 80-90 % of the heat loss occurs in the distribution system. In addition, the heat loss is naturally highest from the forward...

  15. Treatment of low-temperature tar-gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Schick, F

    1928-07-04

    Process for the treating and conversion of low-temperature tar-vapor and gas mixtures in the presence of metals or metal oxides as well as bodies of large surface, without previous condensation of the liquid material to be treated, characterized by the treatment taking place with a mixture of desulfurizing metals and metal oxides which, if necessary, are precipitated on carriers and large surface nonmetal cracking catalysts, such as active carbon and silica gel.

  16. Low Temperature Plasma for the Treatment of Epithelial Cancer Cells

    Science.gov (United States)

    Mohades, Soheila

    Biomedical applications of low temperature plasmas (LTP) may lead to a paradigm shift in treating various diseases by conducting fundamental research on the effects of LTP on cells, tissues, organisms (plants, insects, and microorganisms). This is a rapidly growing interdisciplinary research field that involves engineering, physics, life sciences, and chemistry to find novel solutions for urgent medical needs. Effects of different LTP sources have shown the anti-tumor properties of plasma exposure; however, there are still many unknowns about the interaction of plasma with eukaryotic cells which must be elucidated in order to evaluate the practical potential of plasma in cancer treatment. Plasma, the fourth state of matter, is composed of electrons, ions, reactive molecules (radicals and non-radicals), excited species, radiation, and heat. A sufficient dose (time) of plasma exposure can induce death in cancer cells. The plasma pencil is employed to study the anti-tumor properties of this treatment on epithelial cells. The plasma pencil has been previously used for the inactivation of bacteria, destroying amyloid fibrils, and the killing of various cancer cells. Bladder cancer is the 9th leading cause of cancer. In this dissertation, human urinary bladder tissue with the squamous cell carcinoma disease (SCaBER cells) is treated with LTP utilizing two different approaches: direct plasma exposure and Plasma Activated Media (PAM) as an advancement to the treatment. PAM is produced by exposing a liquid cell culture medium to the plasma pencil. Direct LTP treatment of cancer cells indicates a dose-dependent killing effect at post-treatment times. Similarly, PAM treatment shows an anti-cancer effect by inducing substantial cell death. Reactive oxygen species (ROS) and reactive nitrogen species (RNS) have an important role in the biomedical effects of LTP treatment. This study demonstrates the capability of the plasma pencil to transport ROS/RNS into cell culture media

  17. Low-temperature nuclear heat applications: Nuclear power plants for district heating

    International Nuclear Information System (INIS)

    1987-08-01

    The IAEA reflected the needs of its Member States for the exchange of information in the field of nuclear heat application already in the late 1970s. In the early 1980s, some Member States showed their interest in the use of heat from electricity producing nuclear power plants and in the development of nuclear heating plants. Accordingly, a technical committee meeting with a workshop was organized in 1983 to review the status of nuclear heat application which confirmed both the progress made in this field and the renewed interest of Member States in an active exchange of information about this subject. In 1985 an Advisory Group summarized the Potential of Low-Temperature Nuclear Heat Application; the relevant Technical Document reviewing the situation in the IAEA's Member States was issued in 1986 (IAEA-TECDOC-397). Programme plans were made for 1986-88 and the IAEA was asked to promote the exchange of information, with specific emphasis on the design criteria, operating experience, safety requirements and specifications for heat-only reactors, co-generation plants and power plants adapted for heat application. Because of a growing interest of the IAEA's Member States about nuclear heat employment in the district heating domaine, an Advisory Group meeting was organized by the IAEA on ''Low-Temperature Nuclear Heat Application: Nuclear Power Plants for District Heating'' in Prague, Czechoslovakia in June 1986. The information gained up to 1986 and discussed during this meeting is embodied in the present Technical Document. 22 figs, 11 tabs

  18. Low Temperature District Heating Consumer Unit with Micro Heat Pump for Domestic Hot Water Preparation

    DEFF Research Database (Denmark)

    Zvingilaite, Erika; Ommen, Torben Schmidt; Elmegaard, Brian

    2012-01-01

    In this paper we present and analyse the feasibility of a district heating (DH) consumer unit with micro heat pump for domestic hot water (DHW) preparation in a low temperature (40 °C) DH network. We propose a micro booster heat pump of high efficiency (COP equal to 5,3) in a consumer DH unit...... in order to boost the temperature of the district heating water for heating the DHW. The paper presents the main designs of the suggested system and different alternative micro booster heat pump concepts. Energy efficiency and thermodynamic performance of these concepts are calculated and compared....... The results show that the proposed system has the highest efficiency. Furthermore, we compare thermodynamic and economic performance of the suggested heat pump-based concept with different solutions, using electric water heater. The micro booster heat pump system has the highest annualised investment (390 EUR...

  19. Lauric and palmitic acids eutectic mixture as latent heat storage material for low temperature heating applications

    International Nuclear Information System (INIS)

    Tuncbilek, Kadir; Sari, Ahmet; Tarhan, Sefa; Erguenes, Gazanfer; Kaygusuz, Kamil

    2005-01-01

    Palmitic acid (PA, 59.8 deg. C) and lauric acid (LA, 42.6 deg. C) are phase change materials (PCM) having quite high melting temperatures which can limit their use in low temperature solar applications such as solar space heating and greenhouse heating. However, their melting temperatures can be tailored to appropriate value by preparing a eutectic mixture of the lauric and the palmitic acids. In the present study, the thermal analysis based on differential scanning calorimetry (DSC) technique shows that the mixture of 69.0 wt% LA and 31 wt% PA forms a eutectic mixture having melting temperature of 35.2 deg. C and the latent heat of fusion of 166.3 J g -1 . This study also considers the experimental determination of the thermal characteristics of the eutectic mixture during the heat charging and discharging processes. Radial and axial temperature distribution, heat transfer coefficient between the heat transfer fluid (HTF) pipe and the PCM, heat recovery rate and heat charging and discharging fractions were experimentally established employing a vertical concentric pipe-in-pipe energy storage system. The changes of these characteristics were evaluated with respect to the effect of inlet HTF temperature and mass flow rate. The DSC thermal analysis and the experimental results indicate that the LA-PA eutectic mixture can be a potential material for low temperature thermal energy storage applications in terms of its thermo-physical and thermal characteristics

  20. Low Temperature Heating and High Temperature Cooling in Buildings

    DEFF Research Database (Denmark)

    Kazanci, Ongun Berk

    A heating and cooling system could be divided into three parts: terminal units (emission system), distribution system, and heating and cooling plant (generation system). The choice of terminal unit directly affects the energy performance, and the indoor environment in that space. Therefore, a hol...

  1. Low-temperature heat capacity of molybdenum borides

    International Nuclear Information System (INIS)

    Bolgar, A.S.; Klinder, A.V.; Novoseletskaya, L.M.; Turov, V.P.; Klochkov, L.A.; Lyashchenko, A.B.

    1988-01-01

    Heat capacity of molybdenum borides Mo 2 B, MoB, Mo 2 B 5 is studied for the first time in the 60-300 K range using the adiabatic method. Standard (at 298.15 K) thermodynamic functions (enthalpy, heat capacity, entropy, reduced Gibbs energy) of molybdenum borides are calculated

  2. Dedicated low temperature nuclear district heating plants: Rationale and prospects

    International Nuclear Information System (INIS)

    Goetzmann, C.A.

    1997-01-01

    Space heating accounts for a substantial fraction of the end-energy consumption in a large number of industrialized countries. Accordingly, efforts have been under way since many years to utilize nuclear energy as a source for district heating. The paper describes the key technical and institutional issues affecting the implementation of such technology. It is argued that the basic case for nuclear district heating is sound but that its introduction merits and drawbacks strongly depend on local circumstances. (author). 4 figs, 1 tab

  3. The Specific Heat of Matter at Low Temperatures

    CERN Document Server

    Tari, A

    2003-01-01

    Recent discoveries of new materials and improvements in calorimetric techniques have given new impetus to the subject of specific heat. Nevertheless, there is a serious lack of literature on the subject. This invaluable book, which goes some way towards remedying that, is concerned mainly with the specific heat of matter at ordinary temperatures. It discusses the principles that underlie the theory of specific heat and considers a number of theoretical models in some detail. The subject matter ranges from traditional materials to those recently discovered - heavy fermion compounds, high temper

  4. Dedicated low temperature nuclear district heating plants: Rationale and prospects

    Energy Technology Data Exchange (ETDEWEB)

    Goetzmann, C A [Division of Nuclear Power, International Atomic Energy Agency, Vienna (Austria)

    1997-09-01

    Space heating accounts for a substantial fraction of the end-energy consumption in a large number of industrialized countries. Accordingly, efforts have been under way since many years to utilize nuclear energy as a source for district heating. The paper describes the key technical and institutional issues affecting the implementation of such technology. It is argued that the basic case for nuclear district heating is sound but that its introduction merits and drawbacks strongly depend on local circumstances. (author). 4 figs, 1 tab.

  5. Recovery of low temperature heat in oil mills

    Directory of Open Access Journals (Sweden)

    Carré Patrick

    2012-11-01

    Full Text Available Energy consumption in oil mills is a major item of costs and a sensitive point in the production of biofuels. To improve their performance, industrials can recover lowtemperature heat thanks to a new technology of heat exchangers suitable for treating granular solid materials. Information about the energy requirements of the rapeseed crushing being not readily available, the article gives a detailed assessment of consumption items (per ton of seed: 263 MJ for preparation operations and 284 MJ for solvent extraction. These exchangers used as pre-conditioners saves about 55 MJ.t−1 of heat by use of steam condensates. We could go further in use of these devices on the one hand to recover heat from press cake and meal, and secondly to use recovered energy to dry and warm up the seeds before pre-pressing. In this configuration, the energy savings could reach 38% of current needs.

  6. Heating and Domestic Hot Water Systems in Buildings Supplied by Low-Temperature District Heating

    DEFF Research Database (Denmark)

    Brand, Marek

    solutions simply redirect the bypassed water back to the DH network without additional cooling, but bypassed water can instead be redirected to floor heating in the bathroom to be further cooled and thus reduce heat loss from the DH network while improving comfort for occupants and still ensure fast DHW...... increased risk of Legionella if the DH substation and DHW system are designed for the low-temperature supply conditions. To ensure the fast provision of DHW during non-heating periods, the supply service pipe should be kept warm, preferably with the bypass solution redirecting the bypass flow to bathroom...... temperature. To accord with the literature, the modelling of internal heat gains reflected the improved efficiency of equipment by reduction of value from 5W/m2 to 4.2W/m2, also modelled as intermittent heat gains based on a realistic week schedule. Furthermore, the indoor set-point temperature was increased...

  7. High temperature reactor for the production of low temperature heat

    International Nuclear Information System (INIS)

    Muehlensiep, J.

    1986-12-01

    In this report the conditions of nuclear working reactors for district heating are described for the use in suburban areas. The design of a HTR is analysed under the point of view of safety and costs for the components and for the arrangement possibilities. The size of system is chosen by analysing important parameters for construction. The layout is determined by the retention of fission products in the coated particles of the fuel under conditions of hypothetical accidents. Based on stated data a HTR reactor for district heating will be designed. The speciality is a square shaped core which has the advantage to conduct the afterheat fastly to the outside of the pressure vessel in case of hypothetical accidents. Caused by the shape of the core the heat exchangers may be installed next to the core, the shutdown rods are maintained into reflector borings where they have a high efficiency. The whole primary circuit is surrounded by the reactor pressure vessel and is adjusted in an underground concrete cell. (orig./GL) [de

  8. Low temperature heat capacity of lutetium and lutetium hydrogen alloys

    International Nuclear Information System (INIS)

    Thome, D.K.

    1977-10-01

    The heat capacity of high purity electrotransport refined lutetium was measured between 1 and 20 0 K. Results for theta/sub D/ were in excellent agreement with theta values determined from elastic constant measurements. The heat capacity of a series of lutetium-hydrogen solid solution alloys was determined and results showed an increase in γ from 8.2 to about 11.3 mJ/g-atom-K 2 for hydrogen content increasing from zero to about one atomic percent. Above one percent hydrogen γ decreased with increasing hydrogen contents. The C/T data showed an increase with temperature decreasing below about 2.5 0 K for samples with 0.1 to 1.5 atomic percent hydrogen. This accounts for a large amount of scatter in theta/sub D/ versus hydrogen content in this range. The heat capacity of a bulk sample of lutetium dihydride was measured between 1 and 20 0 K and showed a large increase in theta/sub D/ and a large decrease in γ compared to pure lutetium

  9. Research of management information system of radiation protection for low temperature nuclear heating reactor

    International Nuclear Information System (INIS)

    Bai Hongtao; Wang Jiaying; Wu Manxue

    2001-01-01

    Management information system of radiation protection for low temperature reactor uses computer to manage the data of the low temperature nuclear heating reactor radiation monitoring, it saves the data from the front real-time radiation monitoring system, comparing these data with historical data to give the consequence. Also, the system provides some picture in order to show space information at need. The system, based on Microsoft Access 97, consists of nine parts, including radiation dose, environmental data, meteorological data and so on. The system will have value in safely operation of the low temperature nuclear heating reactor

  10. Expieriences On Low-Temperature District Heating In Lystrup – Denmark

    DEFF Research Database (Denmark)

    Thorsen, Jan Eric; Christiansen, Christian Holm; Brand, Marek

    2011-01-01

    by implementing Low-temperature district heating systems. Demonstration cases in EnergyFlexHouse and Boligforeningen Ringgården” EUDP 2011. A key challenge for optimum and competitive district heating (DH) system operation is reducing heat loss in networks. Today building regulations in most countries demand...

  11. Comparison of Low-temperature District Heating Concepts in a Long-Term Energy System Perspective

    DEFF Research Database (Denmark)

    Lund, Rasmus Søgaard; Østergaard, Dorte Skaarup; Yang, Xiaochen

    2017-01-01

    renewable energy systems. This study compares three alternative concepts for DH temperature level: Low temperature (55/25 °C), Ultra-low temperature with electric boosting (45/25 °C), and Ultra-low temperature with heat pump boosting (35/20 °C) taking into account the grid losses, production efficiencies......District heating (DH) systems are important components in an energy efficient heat supply. With increasing amounts of renewable energy, the foundation for DH is changing and the approach to its planning will have to change. Reduced temperatures of DH are proposed as a solution to adapt it to future...... and building requirements. The scenarios are modelled and analysed in the analysis tool EnergyPLAN and compared on primary energy supply and socioeconomic costs. The results show that the low temperature solution (55/25°C) has the lowest costs, reducing the total costs by about 100 M€/year in 2050....

  12. Analysis and research on promising solutions of low temperature district heating without risk of legionella

    DEFF Research Database (Denmark)

    Yang, Xiaochen; Li, Hongwei; Fog, Jette M.

    2014-01-01

    Most regulations of domestic hot water supply temperature is around 55-60 oC, which potentially requires higher district heating temperature. However, high supply temperature of district heating causes many problems, such as the high heating loss, and obstacles for applying renewable energy...... resources. The most crucial restriction for applying low temperature district heating is the worry about the breakout of legionella, which exists preferably in low temperature hot water systems. Several novel techniques such as electric tracing and flat station were investigated for such dilemma. The pros...... and cons were compared in this paper. Both the energy and economy saving ratios were analysed comparing with high temperature supply scenario. Furthermore, the viability of the applications in different types of buildings for low temperature district heating (LTDH) was also discussed by using dynamic...

  13. Design and modelling of a novel compact power cycle for low temperature heat sources

    DEFF Research Database (Denmark)

    Wronski, Jorrit; Skovrup, Morten Juel; Elmegaard, Brian

    2012-01-01

    Power cycles for the efficient use of low temperature heat sources experience increasing attention. This paper describes an alternative cycle design that offers potential advantages in terms of heat source exploitation. A concept for a reciprocating expander is presented that performs both, work ...

  14. Solar-assisted heat pump – A sustainable system for low-temperature water heating applications

    International Nuclear Information System (INIS)

    Chaturvedi, S.K.; Gagrani, V.D.; Abdel-Salam, T.M.

    2014-01-01

    Highlights: • DX-SAHP water heaters systems are economical as well as energy conserving. • The economic analysis is performed using the life cycle cost (LCC) analysis. • LCC can be optimized with respect to the collector area at a specific temperature. • For high load temperature range a two stage heat pump system is more appropriate. - Abstract: Direct expansion solar assisted heat pump systems (DX-SAHP) have been widely used in many applications including water heating. In the DX-SAHP systems the solar collector and the heat pump evaporator are integrated into a single unit in order to transfer the solar energy to the refrigerant. The present work is aimed at studying the use of the DX-SAHP for low temperature water heating applications. The novel aspect of this paper involves a detailed long-term thermo-economic analysis of the energy conservation potential and economic viability of these systems. The thermal performance is simulated using a computer program that incorporates location dependent radiation, collector, economic, heat pump and load data. The economic analysis is performed using the life cycle cost (LCC) method. Results indicate that the DX-SAHP water heaters systems when compared to the conventional electrical water heaters are both economical as well as energy conserving. The analysis also reveals that the minimum value of the system life cycle cost is achieved at optimal values of the solar collector area as well as the compressor displacement capacity. Since the cost of SAHP system presents a barrier to mass scale commercialization, the results of the present study indicating that the SAHP life cycle cost can be minimized by optimizing the collector area would certainly be helpful in lowering, if not eliminating, the economic barrier to these systems. Also, at load temperatures higher than 70 °C, the performance of the single stage heat pump degrades to the extent that its cost and efficiency advantages over the electric only system are

  15. Achieving low return temperature for domestic hot water preparation by ultra-low-temperature district heating

    DEFF Research Database (Denmark)

    Yang, Xiaochen; Svendsen, Svend

    2017-01-01

    District heating (DH) is a cost-effective method of heat supply, especially to area with high heat density. Ultra-low-temperature district heating (ULTDH) is defined with supply temperature at 35-45 degrees C. It aims at making utmost use of the available low-temperature energy sources. In order...... to achieve high efficiency of the ULTDH system, the return temperature should be as low as possible. For the energy-efficient buildings in the future, it is feasible to use ULTDH to cover the space heating demand. However, considering the comfort and hygiene requirements of domestic hot water (DHW...... lower return temperature and higher efficiency for DHW supply, an innovative substation was devised, which replaced the bypass with an instantaneous heat exchanger and a micro electric storage tank. The energy performance of the proposed substation and the resulting benefits for the DH system...

  16. Towards a Future of District Heating Systems with Low-Temperature Operation together with Non-Fossil Fuel Heat Sources

    DEFF Research Database (Denmark)

    Tol, Hakan; Dinçer, Ibrahim; Svendsen, Svend

    2012-01-01

    This study focused on investigation of non-fossil fuel heat sources to be supplied to low-energy district heating systems operating in low temperature such as 55 C and 25 C in terms of, respectively, supply and return. Vast variety of heat sources classed in categories such as fossil fuel...

  17. The potential to supply low temperature district heating to existing building area

    DEFF Research Database (Denmark)

    Li, Hongwei; Svendsen, Svend

    2013-01-01

    Low-temperature district heating (LTDH) has the advantages as reduced network heat loss, improved quality match between energy supply and energy demand, and increased utilization of low-grade waste heat and renewable energy. The LTDH represents the next generation district heating (DH) system...... to supply existing building areas which are characterized with high heating demand needs to be examined. In this paper, the DH network deliverable capacity to supply LTDH to an existing building area is studied based on building thermal performance and DH network hydraulic performance simulation....

  18. Studies on the low temperature infrared heat processing of soybeans and maize

    NARCIS (Netherlands)

    Kouzeh Kanani, M.

    1985-01-01

    A modified process for the infrared heat processing of oilseeds and cereal grains at relatively low temperatures is put forward. The process which involves an additional holding step and potentials for saving energy was investigated on a pilot plant on the basis of which a design is proposed for

  19. Mathematical Simulation of Convective Heat Transfer in the Low-Temperature Storage of Liquefied Natural Gas

    OpenAIRE

    Shestakov, Igor; Dolgova, Anastasia; Maksimov, Vyacheslav Ivanovich

    2015-01-01

    The article shows the results of mathematical modeling of convective heat transfer in the low-temperature storage of liquefied natural gas. Regime of natural convection in an enclosure with different intensity of the heat flux at the external borders are investigated. Was examined two-dimensional nonstationary problem within the model of Navier-Stokes in dimensionless variables “vorticity - stream function - temperature”. Distributions of hydrodynamic parameters and temperatures that characte...

  20. Development of an innovative low temperature heat supply concept for a new housing area

    OpenAIRE

    Schmidt, Dietrich; Kallert, Anna; Orozaliev, Janybek; Best, Isabelle; Vajen, Klaus; Reul, Oliver; Bennewitz, Jochen; Gerhold, Petra

    2017-01-01

    The domestic energy demand of buildings is responsible for one third of the world's final energy consumption. To increase the sustainability of new housing areas, the identification of innovative heat supply concepts based on renewable energy sources (RES) is required. For the new housing area “Zum Feldlager” (Kassel, Germany), various supply concepts are studied. Main objective is the development of an innovative and efficient supply concept based on RES and low temperature district heating ...

  1. A low temperature aluminizing treatment of hot work tool steel

    Energy Technology Data Exchange (ETDEWEB)

    Matijevic, B., E-mail: bozidar.matijevic@fsb.hr [University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, Zagreb (Croatia)

    2010-07-01

    Conventional aluminizing processes by pack cementation are typically carried out at elevated temperatures. A low temperature powder aluminizing technology was applied to hot tool steel H13. The aluminizing treating temperature was from 550 to 620°C. Effects of temperature and time on the microstructure and phase evolution were investigated. Also, the intermetallic layer thickness was measured in the aluminized layer of a steel substrate. The cross-sectional microstructures, the aluminized layer thickness and the oxide layer were studied. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), glow discharge optical spectroscopy (GDOS) were applied to observe the cross-sections and the distribution of elements. (author)

  2. A LOW TEMPERATURE ALUMINIZING TREATMENT OF HOT WORK TOOL STEEL

    OpenAIRE

    Matijević, Božidar

    2013-01-01

    Conventional aluminizing processes by pack cementation are typically carried out at elevated temperatures. A low temperature powder aluminizing technology was applied to the X40CrMoV5-1 hot tool steel. The aluminizing temperature was from 550 °C to 620 °C. Effects of temperature and time on the microstructure and phase evolution were investigated. Also, the intermetallic layer thickness was measured in the aluminized layer of a steel substrate. The cross-sectional microstructures, the alumini...

  3. A low temperature aluminizing treatment of hot work tool steel

    International Nuclear Information System (INIS)

    Matijevic, B.

    2010-01-01

    Conventional aluminizing processes by pack cementation are typically carried out at elevated temperatures. A low temperature powder aluminizing technology was applied to hot tool steel H13. The aluminizing treating temperature was from 550 to 620°C. Effects of temperature and time on the microstructure and phase evolution were investigated. Also, the intermetallic layer thickness was measured in the aluminized layer of a steel substrate. The cross-sectional microstructures, the aluminized layer thickness and the oxide layer were studied. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), glow discharge optical spectroscopy (GDOS) were applied to observe the cross-sections and the distribution of elements. (author)

  4. Decentralized substations for low-temperature district heating with no Legionella risk, and low return temperatures

    International Nuclear Information System (INIS)

    Yang, Xiaochen; Li, Hongwei; Svendsen, Svend

    2016-01-01

    To improve energy efficiency and give more access to renewable energy sources, low-temperature district heating (LTDH) is a promising concept to be realized in the future. However, concern about Legionella proliferation restricts applying low-temperature district heating in conventional systems with domestic hot water (DHW) circulation. In this study, a system with decentralized substations was analysed as a solution to this problem. Furthermore, a modification for the decentralized substation system were proposed in order to reduce the average return temperature. Models of conventional system with medium-temperature district heating, decentralized substation system with LTDH, and innovative decentralized substation system with LTDH were built based on the information of a case building. The annual distribution heat loss and the operating costs of the three scenarios were calculated and compared. From the results, realizing LTDH by the decentralized substation unit, 30% of the annual distribution heat loss inside the building can be saved compared to a conventional system with medium-temperature district heating. Replacing the bypass pipe with an in-line supply pipe and a heat pump, the innovative decentralized substation system can reduce distribution heat loss by 39% compared to the conventional system and by 12% compared to the normal decentralized substation system with bypass. - Highlights: • The system of decentralized substations can realize low-temperature district heating without running the risk of Legionella. • Decentralized substations help reduce the distribution heat loss inside the building compared to conventional system. • A new concept that can reduce the return temperature for district heating is proposed and analysed.

  5. Experimental study of energy performance in low-temperature hydronic heating systems

    DEFF Research Database (Denmark)

    Hesaraki, Arefeh; Bourdakis, Eleftherios; Ploskić, Adnan

    2015-01-01

    Energy consumption, thermal environment and environmental impacts were analytically and experimentally studied for different types of heat emitters. The heat emitters studied were conventional radiator, ventilation radiator, and floor heating with medium-, low-, and very-low-temperature supply....... The supply water temperature in all measurements for conventional radiator was significantly higher than ventilation radiator and floor heating; namely, 45°C. Experimental results indicated that the mean indoor temperature was close to the acceptable level of 22°C in all cases. For energy calculations......, it was assumed that all heat emitters were connected to a ground-source heat pump. Analytical calculations showed that using ventilation radiator and floor heating instead of conventional radiator resulted in a saving of 17% and 22% in heat pump's electricity consumption, respectively. This would reduce the CO2...

  6. [The design of heat dissipation of the field low temperature box for storage and transportation].

    Science.gov (United States)

    Wei, Jiancang; Suin, Jianjun; Wu, Jian

    2013-02-01

    Because of the compact structure of the field low temperature box for storage and transportation, which is due to the same small space where the compressor, the condenser, the control circuit, the battery and the power supply device are all placed in, the design for heat dissipation and ventilation is of critical importance for the stability and reliability of the box. Several design schemes of the heat dissipation design of the box were simulated using the FLOEFD hot fluid analysis software in this study. Different distributions of the temperature field in every design scheme were constructed intimately in the present study. It is well concluded that according to the result of the simulation analysis, the optimal heat dissipation design is decent for the field low temperature box for storage and transportation, and the box can operate smoothly for a long time using the results of the design.

  7. Laboratory study of subjective perceptions to low temperature heating systems with exhaust ventilation in Nordic countries

    DEFF Research Database (Denmark)

    Jin, Quan; Simone, Angela; Olesen, Bjarne W.

    2017-01-01

    Given the global trends of rising energy demand and the increasing utilization of low-grade renewable energy, low-temperature heating systems can play key roles in improving building energy efficiency while providing a comfortable indoor environment. To meet the need to retrofit existing buildings...... in Nordic countries for greater energy efficiency, this study focused on human subjects’ thermal sensation, thermal comfort, thermal acceptability, draft acceptability, and perceived air quality when three low-temperature heating systems were used: conventional radiator, ventilation radiator, or floor...... heating with exhaust ventilation. Human subject tests were carried out in the climate chamber at the Technical University of Denmark. In total, 24 human subjects, 12 females and 12 males, participated in the tests during the winter season. The results show that no significant differences in thermal...

  8. Low temperature industrial waste heat utilization in the area 'Speyer-Ludwigshafen-Frankenthal-Worms'

    International Nuclear Information System (INIS)

    Nunold, K.; Krebs, A.

    1982-01-01

    The aim of the study is the elaboration of reliable facts whether and under which conditions low temperature industrial waste heat systems can be economically utilized for heating purposes. The source of the waste heat are power- and industrial plants. In order to obtain reliable results, investigations have been carried out in the area Speyer-Ludwigshafen-Frankenthal and Worms. These investigations showed a number of application possibilities for heat pumps and it became moreover evident that there is a high variaiton of the heat requirement due to social components and the different type of building structures of the consumers. The economic results showed that the application of this heating system can under certain conditions supplement resp. replace other heating systems. (orig.) [de

  9. Applying the principles of thermoeconomics to the organic Rankine Cycle for low temperature waste heat recovery

    International Nuclear Information System (INIS)

    Xiao, F.; Lilun, Q.; Changsun, S.

    1989-01-01

    In this paper, thermoeconomic principle is used to study the selection of working fluids and the option of the cycle parameters in the organic Rankine cycle of low temperature waste heat recovery. The parameter ξ, the product of the ratio of waste heat recovery and real cycle thermal efficiency, is suggested as a unified thermodynamic criterion for the selection of the working fluids. The mathematical expressions are developed to determine the optimal boiling temperature and the optimal pin point temperature difference in the heat recovery exchanger by way of thermoeconomic principle

  10. Evaluations of different domestic hot water preparing methods with ultra-low-temperature district heating

    DEFF Research Database (Denmark)

    Yang, Xiaochen; Li, Hongwei; Svendsen, Svend

    2016-01-01

    of Legionella in the DHW (domestic hot water) and assure the comfortable temperature, all substations were installed with supplementary heating devices. Detailed measurements were taken in the substations, including the electricity demand of the supplementary heating devices. To compare the energy and economic......This study investigated the performances of five different substation configurations in single-family houses supplied with ULTDH (ultra-low-temperature district heating). The temperature at the heat plant is 46 degrees C and around 40 degrees C at the substations. To avoid the proliferation...... performance of the substations, separate models were built based on standard assumptions. The relative heat and electricity delivered for preparing DHW were calculated. The results showed that substations with storage tanks and heat pumps have high relative electricity demand, which leads to higher integrated...

  11. Alternative solutions for inhibiting Legionella in domestic hot water systems based on low-temperature district heating

    DEFF Research Database (Denmark)

    Yang, Xiaochen; Li, Hongwei; Svendsen, Svend

    2015-01-01

    Abstract District heating is a cost-effective way of providing heat to high heat density areas. Low-temperature district heating (LTDH) is a promising way to make district heating more energy-efficient and adaptable to well-insulated buildings with low heating demand in the future. However, one c...... systems. They have the additional benefit of reducing the heat loss of the hot water system. The alternative design solutions both enrich our options for water sanitation and improve the energy efficiency of our energy systems....... concern is the multiplication of Legionella due to insufficient temperature elevation with low-temperature supply. The aim of this study was to find optimal solutions to this dilemma for specific situations. The solutions were of two types: alternative system designs and various methods of sterilization...... methods, thermal treatment, ionization, chlorine, chlorine dioxide, ultraviolet light, photocatalysis and filtration are discussed as the most frequently used methods in hot water systems. The characteristics, efficacy and operation methods of LTDH using the solutions investigated are documented...

  12. Analysis of the Potential of Low-Temperature Heat Pump Energy Sources

    Directory of Open Access Journals (Sweden)

    Pavel Neuberger

    2017-11-01

    Full Text Available The paper deals with an analysis of temperatures of ground masses in the proximities of linear and slinky-type HGHE (horizontal ground heat exchanger. It evaluates and compares the potentials of HGHEs and ambient air. The reason and aim of the verification was to gain knowledge of the temperature course of the monitored low-temperature heat pump energy sources during heating periods and periods of stagnation and to analyse the knowledge in terms of the potential to use those sources for heat pumps. The study was conducted in the years 2012–2015 during three heating periods and three periods of HGHEs stagnation. The results revealed that linear HGHE had the highest temperature potential of the observed low-temperature heat pump energy sources. The average daily temperatures of the ground mass surrounding the linear HGHE were the highest ranging from 7.08 °C to 9.20 °C during the heating periods, and having the lowest temperature variation range of 12.62–15.14 K, the relative frequency of the average daily temperatures of the ground mass being the highest at 22.64% in the temperature range containing the mode of all monitored temperatures in a recorded interval of [4.10, 6.00] °C. Ambient air had lower temperature potential than the monitored HGHEs.

  13. Flue gas heat recovery operating below the dew point and its utilisation for low temperature heating installations

    Energy Technology Data Exchange (ETDEWEB)

    Wilsdorf, J.

    1986-11-01

    This paper deals at first with the characteristics of two principal systems for the flue gas heat recovery by reducing the temperature below the dew point. With test results on experimental plants are shown the typical differences between surface and direct contact heat exchange. A second part informs about experiences from the application for low temperature heating installations, especially about thermodynamics condensate quality and technical design. The possible increasing of the efficiency ranges between 10 to 20 per cent.

  14. Energy Efficiency of Low-Temperature Deaeration of Makeup Water for a District Heating System

    Energy Technology Data Exchange (ETDEWEB)

    Sharapov, V. I., E-mail: vlad-sharapov2008@yandex.ru; Kudryavtseva, E. V. [Ulyanovsk State Technical University (Russian Federation)

    2016-07-15

    It is shown that the temperature of makeup water in district heating systems has a strong effect on the energy efficiency of turbines of thermal power plants. A low-temperature deaeration process that considerably improves the energy efficiency of thermal power plants is developed. The desorbing agent is the gas supplied to the burners of the boiler. The energy efficiency of the process for a typical unit of thermal power plant is assessed.

  15. Experimental Study of the Performance of Air Source Heat Pump Systems Assisted by Low-Temperature Solar-Heated Water

    Directory of Open Access Journals (Sweden)

    Jinshun Wu

    2013-01-01

    Full Text Available Due to the low temperatures, the heating efficiency of air source heat pump systems during the winter is very low. To address this problem, a low-temperature solar hot water system was added to a basic air source heat pump system. Several parameters were tested and analyzed. The heat collection efficiency of the solar collector was analyzed under low-temperature conditions. The factors that affect the performance of the heat pumps, such as the fluid temperature, pressure, and energy savings, were analyzed for cases where the solar energy auxiliary heat pump and the air source heat pump are used independently. The optimal heating temperature and the changes in the fluid temperature were determined. The influence of the compression ratio and the coefficient of performance (COP were investigated theoretically. The results revealed the parameters that are important to the performance of the system. Several measures for improving the COP of the heat pump units are provided for other applications and future research.

  16. Evaluations of different domestic hot water preparing methods with ultra-low-temperature district heating

    International Nuclear Information System (INIS)

    Yang, Xiaochen; Li, Hongwei; Svendsen, Svend

    2016-01-01

    This study investigated the performances of five different substation configurations in single-family houses supplied with ULTDH (ultra-low-temperature district heating). The temperature at the heat plant is 46 °C and around 40 °C at the substations. To avoid the proliferation of Legionella in the DHW (domestic hot water) and assure the comfortable temperature, all substations were installed with supplementary heating devices. Detailed measurements were taken in the substations, including the electricity demand of the supplementary heating devices. To compare the energy and economic performance of the substations, separate models were built based on standard assumptions. The relative heat and electricity delivered for preparing DHW were calculated. The results showed that substations with storage tanks and heat pumps have high relative electricity demand, which leads to higher integrated costs considering both heat and electricity for DHW preparation. The substations with in-line electric heaters have low relative electricity usage because very little heat is lost due to the instantaneous DHW preparation. Accordingly, the substations with in-line electric heaters would have the lowest energy cost for DHW preparation. To achieve optimal design and operation for the ULTDH substation, the electricity peak loads of the in-line electric heaters were analysed according to different DHW-heating strategies. - Highlights: • Five different substations supplied with ultra-low-temperature district heating were measured. • The relative heat and electricity delivered for DHW preparation were modelled for different substations. • The levelized cost of the five substations in respect of DHW preparation was calculated. • The feasibility of applying instantaneous electric heater with normal power supply was tested.

  17. Low-temperature waste-heat recovery in the food and paper industries

    Energy Technology Data Exchange (ETDEWEB)

    Foell, W.K.; Lund, D.; Mitchell, J.W.; Ray, D.; Stevenson, R.; TenWolde, A.

    1980-11-01

    The potential of low-temperature waste-heat recovery technology is examined. An examination of barriers to impede waste-heat recovery is made and research programs are identified. Extensive information and data are presented in the following chapters: Waste Heat Recovery in the Wisconsin Food Industry; Waste Heat Recovery in the Wisconsin Pulp and Paper Industry; Industries' Economic Analysis of Energy Conservation Projects; Industrial Waste Heat Recovery (selection of heat-recovery heat exchangers for industrial applications, simplified procedure for selection of heat recovery heat exchangers for industrial applications, selection of heat pumps for industrial applications); Institutional Aspects of Industrial Energy Conservation (economic motivation for energy conservation and the industrial response, intrafirm idea channels and their sources, evaluation and approval of plant improvement projects, reported barriers to adopting waste heat recovery projects and recommendations for government involvement, and the final chapter is a summary with major conclusions given. Additional information is given in two appendices on the potential waste heat recovery in a cheese plant (calculation) and conditions for optimum exchanger size and break-even fuel cost. (MCW)

  18. Specific heat studies of pure Nb3Sn single crystals at low temperature

    International Nuclear Information System (INIS)

    Escudero, R; Morales, F; Bernes, S

    2009-01-01

    Specific heat measurements performed on high purity vapor-grown Nb 3 Sn crystals show clear features related to both the martensitic and superconducting transitions. Our measurements indicate that the martensitic anomaly does not display hysteresis, meaning that the martensitic transition could be a weak first-order or a second-order thermodynamic transition. Careful measurements of the two transition temperatures display an inverse correlation between them. At low temperature, specific heat measurements show the existence of a single superconducting energy gap feature.

  19. Low-temperature specific heat of YMn sub 2 in the paramagnetic and antiferromagnetic phases

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, R.A.; Emerson, J.P.; Phillips, N.E. (Lawrence Berkeley Lab., CA (United States)); Ballou, R.; Lelievre-Berna, E. (Centre National de la Recherche Scientifique (CNRS), 38 - Grenoble (France). Lab. Louis Neel)

    1992-07-01

    The low-temperature specific heat of YMn{sub 2} has been measured at applied pressures of 0 to 7.7 kbar. A paramagnetic state is stabilized for moderate values of the applied pressure (of the order of 1.6 kbar). A large linear term in the specific heat, which decreases regularly with increasing pressure, is observed in this phase. It is ascribed to giant spin fluctuations associated with a magnetic-non magnetic instability and a strong geometrical spin frustration.

  20. Performance analysis of double organic Rankine cycle for discontinuous low temperature waste heat recovery

    International Nuclear Information System (INIS)

    Wang Dongxiang; Ling Xiang; Peng Hao

    2012-01-01

    This research proposes a double organic Rankine cycle for discontinuous waste heat recovery. The optimal operation conditions of several working fluids have been calculated by a procedure employing MATLAB and REFPROP. The influence of outlet temperature of heat source on the net power output, thermal efficiency, power consumption, mass flow rate, expander outlet temperature, cycle irreversibility and exergy efficiency at a given pinch point temperature difference (PPTD) has been analyzed. Pinch point analysis has also been employed to obtain a thermodynamic understanding of the ORC performance. Of all the working fluids investigated, some performances between each working fluid are rather similar. For a fixed low temperature heat source, the optimal operation condition should be mainly determined by the heat carrier of the heat source, and working fluids have limited influence. Lower outlet temperature of heat source does not always mean more efficient energy use. Acetone exhibits the least exergy destruction, while R245fa possesses the maximal exergy efficiency at a fixed PPTD. Wet fluids exhibit lower thermal efficiency than the others with the increasing of PPTD at a fixed outlet temperature of heat source. Dry and isentropic fluids offer attractive performance. - Highlights: ► We propose a double organic Rankine cycle for discontinuous waste heat recovery. ► Performance of organic Rankine cycle (ORC) is analyzed by pinch point analysis. ► The heat carrier of the heat source determines ORC optimal operation condition. ► Design of ORC heat exchangers prefers lower pinch point temperature difference.

  1. Effect of low-temperature thermomechanical treatment on mechanical properties of low-alloying molybdenum alloys with carbide hardening

    International Nuclear Information System (INIS)

    Bernshtejn, L.M.; Zakharov, A.M.; Veller, M.V.

    1978-01-01

    Presented are results of testing low-temperature thermomechanical treatment of low-alloying molybdenum alloys, including quenching from 2100 deg C, 40% deformation by hydroextrusion and aging at the temperature of 1200-1400 deg C. Tensile tests at room temperature with the following processing of results have shown that low-temperature thermomechanical treatment of low-alloying molybdenum alloys of Mo-Zr-C and Mo-Zr-Nb-C systems leads to a significant increase in low-temperature mechanical properties (strength properties - by 30-35%, ductility - by 30-40%) as compared with conventional heat treatment (aging after quenching). The treatment proposed increases resistance to small, as well as large plastic deformations, and leads to a simultaneous rise of strength and plastic properties at all stages of tensile test. Alloying of the Mo-Zr-C system with niobium increases both strength and plastic characteristics as compared with alloys without niobium when testing samples, subjected to low temperature thermomechanical treatment and conventional heat treatment at room temperature

  2. Performance analysis of a low-temperature waste heat-driven adsorption desalination prototype

    KAUST Repository

    Thu, Kyaw

    2013-10-01

    This paper discusses the performance analysis of an advanced adsorption desalination (AD) cycle with an internal heat recovery between the condenser and the evaporator. The AD cycle employs the adsorption-desorption principles to convert sea or brackish water into high-grade potable water with total dissolved solids (TDS) less than 10 ppm (mg/L) utilizing low-temperature heat source. The salient features of the AD cycle are the utilization of low temperature waste heat (typically 55 C to 85 C) with the employment of an environment-friendly silica gel/water pair and the low maintenance as it has no major moving parts other than the pumps and valves. For improved performance of the AD pilot plant, the internal heat recovery scheme between the condenser and evaporator has been implemented with a run-about water circuit between them. The efficacy of the scheme is analyzed in terms of key performance indicators such as the specific daily water production (SDWP) and the performance ratio (PR). Extensive experiments were performed for assorted heat source temperatures ranging from 70 C to 50 C. From the experiments, the SDWP of the AD cycle with the proposed heat recovery scheme is found to be 15 m3 of water per ton of silica gel that is almost twice that of the yield obtained by a conventional AD cycle for the same operation conditions. Another important finding of AD desalination plant is that the advanced AD cycle could still be operational with an inlet heat source temperature of 50 C and yet achieving a SDWP of 4.3 m3 - a feat that never seen by any heat-driven cycles. © 2013 Elsevier Ltd. All rights reserved.

  3. Mathematical Simulation of Convective Heat Transfer in the Low-Temperature Storage of Liquefied Natural Gas

    Directory of Open Access Journals (Sweden)

    Shestakov Igor A.

    2015-01-01

    Full Text Available The article shows the results of mathematical modeling of convective heat transfer in the low-temperature storage of liquefied natural gas. Regime of natural convection in an enclosure with different intensity of the heat flux at the external borders are investigated. Was examined two-dimensional nonstationary problem within the model of Navier-Stokes in dimensionless variables “vorticity - stream function - temperature”. Distributions of hydrodynamic parameters and temperatures that characterize the basic regularities of the processes are obtained. Circulating flows are determined and carried out the analysis of vortices formation mechanism and the temperature distribution in solution at conditions of natural convection when the Grashof number (Gr = 106. A significant influence of heat transfer rate on solutions boundary on flow structure and temperature field in LNG storage tanks.

  4. On the low-temperature specific heat of icosahedral and decagonal quasicrystals

    International Nuclear Information System (INIS)

    Chernikov, M.A.

    2005-01-01

    Calorimetric experiments on icosahedral (Al-Re-Pd, Al-Mn-Pd) and decagonal (Al-Cu-Co, Al-Ni-Co) quasicrystals are described. For quasicrystals of both classes, the coefficient γ of the linear term to the specific heat falls into the range of 0.1-0.6 mJ/g-atom K 2 indicating a low density of energy states at Fermi level. For icosahedral Al-Mn-Pd, the cubic-in-temperature term to the specific heat is distinctly larger than the estimated contribution of long-wave acoustic excitations. On the contrary, the magnitude of the cubic-in-temperature term to the specific heat of decagonal Al-Ni-Co is in agreement,within the experimental accuracy, with the Debye acoustic contribution from the results of low-temperature measurements of the elastic modules [ru

  5. Effects of phonon dimensionality in the specific heat of multiwall carbon nanotubes at low temperatures

    International Nuclear Information System (INIS)

    Jorge, Guillermo A; Bekeris, V; Acha, C; Escobar, M M; Goyanes, S; Zilli, D; Cukierman, A L; Candal, R J

    2009-01-01

    We have measured the specific heat at constant pressure, C p , of three different samples of multiwall carbon nanotubes (MWNT). For all samples, C p departs from a graphitic behavior at T p measurements show a temperature threshold from a linear regime for intermediate temperature to a higher-order power law for low temperatures. Moreover, it was found that this crossover only depends on the internal structure of the individual MWNT and not on the spatial order of the MWNT within a bundle.

  6. Low-temperature specific heat of the β-pyrochlore oxide superconductors under high pressure

    Science.gov (United States)

    Isono, T.; Iguchi, D.; Machida, Y.; Izawa, K.; Salce, B.; Flouquet, J.; Ogusu, H.; Yamaura, J.; Hiroi, Z.

    2011-01-01

    We report the results of the low-temperature specific heat measurements of the single crystalline β-pyrochlore oxide superconductors AOs 2O 6 (A=K, Rb, and Cs) under high pressure up to 13 GPa. We find that superconducting transition temperature ( Tc) monotonically increases for CsOs 2O 6 and RbOs 2O 6, while the one for KOs 2O 6 decreases by applying the pressure. With further increasing the pressure, Tc is suddenly suppressed at the same lattice volume for all compounds, concomitant with the first-order structural phase transition.

  7. Effects of phonon dimensionality in the specific heat of multiwall carbon nanotubes at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Jorge, Guillermo A; Bekeris, V; Acha, C [Laboratorio de Bajas Temperaturas, Departamento de Fisica, FCEyN-UBA, Pab. 1, Ciudad Universitaria (1428), Buenos Aires (Argentina); Escobar, M M; Goyanes, S [Laboratorio de Polimeros y Materiales Compuestos, Departamento de Fisica, FCEyN-UBA, Pab. 1, Ciudad Universitaria (1428), Buenos Aires (Argentina); Zilli, D; Cukierman, A L [PINMATE, Departamento de Industrias, FCEyN-UBA, Pab. Industrias, Ciudad Universitaria (1428), Buenos Aires (Argentina); Candal, R J, E-mail: gjorge@df.uba.a [Instituto de Fisicoquimica de Materiales, Ambiente y EnergIa, CONICET-UBA, Ciudad Universitaria (1428) Buenos Aires (Argentina)

    2009-05-01

    We have measured the specific heat at constant pressure, C{sub p}, of three different samples of multiwall carbon nanotubes (MWNT). For all samples, C{sub p} departs from a graphitic behavior at T < 120 K. C{sub p} measurements show a temperature threshold from a linear regime for intermediate temperature to a higher-order power law for low temperatures. Moreover, it was found that this crossover only depends on the internal structure of the individual MWNT and not on the spatial order of the MWNT within a bundle.

  8. Renewable-based low-temperature district heating for existing buildings in various stages of refurbishment

    DEFF Research Database (Denmark)

    Brand, Marek; Svendsen, Svend

    2013-01-01

    Denmark is aiming for a fossil-free heating sector for buildings by 2035. Judging by the national heating plan, this will be achieved mainly by a further spread of DH (district heating) based on the renewable heat sources. To make the most cost-effective use of these sources, the DH supply...... and, for 98% of the year, to below 60 °C. However for the temperatures below 60 °C a low-temperature DH substation is required for DHW (domestic hot water) heating. This research shows that renewable sources of heat can be integrated into the DH system without problems and contribute to the fossil...... temperature should be as low as possible. We used IDA–ICE software to simulate a typical Danish single-family house from the 1970s connected to DH at three different stages of envelope and space heating system refurbishment. We wanted to investigate how low the DH supply temperature can be without reducing...

  9. Evaporation heat transfer of carbon dioxide at low temperature inside a horizontal smooth tube

    Science.gov (United States)

    Yoon, Jung-In; Son, Chang-Hyo; Jung, Suk-Ho; Jeon, Min-Ju; Yang, Dong-Il

    2017-05-01

    In this paper, the evaporation heat transfer coefficient of carbon dioxide at low temperature of -30 to -20 °C in a horizontal smooth tube was investigated experimentally. The test devices consist of mass flowmeter, pre-heater, magnetic gear pump, test section (evaporator), condenser and liquid receiver. Test section is made of cooper tube. Inner and outer diameter of the test section is 8 and 9.52 mm, respectively. The experiment is conducted at mass fluxes from 100 to 300 kg/m2 s, saturation temperature from -30 to -20 °C. The main results are summarized as follows: In case that the mass flux of carbon dioxide is 100 kg/m2 s, the evaporation heat transfer coefficient is almost constant regardless of vapor quality. In case of 200 and 300 kg/m2 s, the evaporation heat transfer coefficient increases steadily with increasing vapor quality. For the same mass flux, the evaporation heat transfer coefficient increases as the evaporation temperature of the refrigerant decreases. In comparison of heat transfer correlations with the experimental result, the evaporation heat transfer correlations do not predict them exactly. Therefore, more accurate heat transfer correlation than the previous one is required.

  10. Scale Resistant Heat Exchanger for Low Temperature Geothermal Binary Cycle Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Hays, Lance G. [Energent Corporation, Santa Ana, CA (United States)

    2014-11-18

    Phase 1 of the investigation of improvements to low temperature geothermal power systems was completed. The improvements considered were reduction of scaling in heat exchangers and a hermetic turbine generator (eliminating seals, seal system, gearbox, and lube oil system). A scaling test system with several experiments was designed and operated at Coso geothermal resource with brine having a high scaling potential. Several methods were investigated at the brine temperature of 235 ºF. One method, circulation of abradable balls through the brine passages, was found to substantially reduce scale deposits. The test heat exchanger was operated with brine outlet temperatures as low as 125 ºF, which enables increased heat input available to power conversion systems. For advanced low temperature cycles, such as the Variable Phase Cycle (VPC) or Kalina Cycle, the lower brine temperature will result in a 20-30% increase in power production from low temperature resources. A preliminary design of an abradable ball system (ABS) was done for the heat exchanger of the 1 megawatt VPC system at Coso resource. The ABS will be installed and demonstrated in Phase 2 of this project, increasing the power production above that possible with the present 175 ºF brine outlet limit. A hermetic turbine generator (TGH) was designed and manufacturing drawings produced. This unit will use the working fluid (R134a) to lubricate the bearings and cool the generator. The 200 kW turbine directly drives the generator, eliminating a gearbox and lube oil system. Elimination of external seals eliminates the potential of leakage of the refrigerant or hydrocarbon working fluids, resulting in environmental improvement. A similar design has been demonstrated by Energent in an ORC waste heat recovery system. The existing VPC power plant at Coso was modified to enable the “piggyback” demonstration of the TGH. The existing heat exchanger, pumps, and condenser will be operated to provide the required

  11. District Heating Expansion Potential with Low-Temperature and End-Use Heat Savings

    DEFF Research Database (Denmark)

    Nielsen, Steffen; Grundahl, Lars

    2018-01-01

    District heating has the potential to play a key role in the transition towards a renewable energy system. However, the development towards reduced heat demands threatens the feasibility of district heating. Despite this challenge, opportunity exists in the form of fourth generation district...... heating, which operates at lower temperatures and enables better renewable integration. This article investigates this challenge by examining the district heating potential within three scenarios: The first is a reference scenario with current heat demand and temperatures, the second includes heat demand...... costs. The models are applied using an example case of The Northern Region of Denmark. The article concludes that the district heating potential is highest in the reference scenario. When heat savings are introduced, district heating expansions, in most cases, will not be feasible. Introducing low...

  12. Numerical research of heat and mass transfer during low-temperature ignition of a coal particle

    Directory of Open Access Journals (Sweden)

    Glushkov Dmitrii O.

    2015-01-01

    Full Text Available Numerical researches have been carried out to study the influence of air flow temperature and a fossil fuel particle rate on sufficient conditions of ignition in a “coal particle - air” system. Developed mathematical model takes into account interconnected processes of heat transfer in a coal particle and gas area, thermal decomposition of organic material, diffusion and gas-phase oxidation of volatiles, heating of a coke (carbon and its heterogeneous ignition. The effect of low-temperature (about 600 K ignition for a single coal particle is impossible even at variation of its rate (radius from 0.05 mm to 0.5 mm. Nevertheless this process is possible for group of particles (two, three, et al. situated at close-range from each other. The physical aspects of the problem are discussed.

  13. Optimal Design of ORC Systems with a Low-Temperature Heat Source

    Directory of Open Access Journals (Sweden)

    Nicolas Galanis

    2012-02-01

    Full Text Available A numerical model of subcritical and trans-critical power cycles using a fixed-flowrate low-temperature heat source has been validated and used to calculate the combinations of the maximum cycle pressure (Pev and the difference between the source temperature and the maximum working fluid temperature (DT which maximize the thermal efficiency (ηth or minimize the non-dimensional exergy losses (β, the total thermal conductance of the heat exchangers (UAt and the turbine size (SP. Optimum combinations of Pev and DT were calculated for each one of these four objective functions for two working fluids (R134a, R141b, three source temperatures and three values of the non-dimensional power output. The ratio of UAt over the net power output (which is a first approximation of the initial cost per kW shows that R141b is the better working fluid for the conditions under study.

  14. Low temperature treatment affects concentration and distribution of chrysanthemum stunt viroid in Argyranthemum

    Directory of Open Access Journals (Sweden)

    Zhibo eZhang

    2016-03-01

    Full Text Available Chrysanthemum stunt viroid (CSVd can infect Argyranthemum and cause serious economic loss. Low temperature treatment combined with meristem culture has been applied to eradicate viroids from their hosts, but without success in eliminating CSVd from diseased Argyranthemum. The objectives of this work were to investigate 1 the effect of low temperature treatment combined with meristem culture on elimination of CSVd, 2 the effect of low temperature treatment on CSVd distribution pattern in shoot apical meristem (SAM, and 3 CSVd distribution in flowers and stems of two infected Argyranthemum cultivars. After treatment with low temperature combined with meristem tip culture, two CSVd-free plants were found in ‘Border Dark Red’, but none in ‘Yellow Empire’. With the help of in situ hybridization, we found that CSVd distribution patterns in the SAM showed no changes in diseased ‘Yellow Empire’ following 5oC treatment, compared with non-treated plants. However, the CSVd-free area in SAM was enlarged in diseased ‘Border Dark Red’ following prolonged 5oC treatment. Localization of CSVd in the flowers and stems of infected ‘Border Dark Red’ and ‘Yellow Empire’ indicated that seeds could not transmit CSVd in these two cultivars, and CSVd existed in phloem. Results obtained in the study contributed to better understanding of the distribution of CSVd in systemically infected plants and the combination of low temperature treatment and meristem tip culture for production of viroid-free plants.

  15. Low temperature heat capacities and thermodynamic functions described by Debye-Einstein integrals.

    Science.gov (United States)

    Gamsjäger, Ernst; Wiessner, Manfred

    2018-01-01

    Thermodynamic data of various crystalline solids are assessed from low temperature heat capacity measurements, i.e., from almost absolute zero to 300 K by means of semi-empirical models. Previous studies frequently present fit functions with a large amount of coefficients resulting in almost perfect agreement with experimental data. It is, however, pointed out in this work that special care is required to avoid overfitting. Apart from anomalies like phase transformations, it is likely that data from calorimetric measurements can be fitted by a relatively simple Debye-Einstein integral with sufficient precision. Thereby, reliable values for the heat capacities, standard enthalpies, and standard entropies at T  = 298.15 K are obtained. Standard thermodynamic functions of various compounds strongly differing in the number of atoms in the formula unit can be derived from this fitting procedure and are compared to the results of previous fitting procedures. The residuals are of course larger when the Debye-Einstein integral is applied instead of using a high number of fit coefficients or connected splines, but the semi-empiric fit coefficients keep their meaning with respect to physics. It is suggested to use the Debye-Einstein integral fit as a standard method to describe heat capacities in the range between 0 and 300 K so that the derived thermodynamic functions are obtained on the same theory-related semi-empiric basis. Additional fitting is recommended when a precise description for data at ultra-low temperatures (0-20 K) is requested.

  16. Thermodynamic analysis of a low-temperature waste heat recovery system based on the concept of solar chimney

    International Nuclear Information System (INIS)

    Chen, Kai; Wang, Jiangfeng; Dai, Yiping; Liu, Yuqi

    2014-01-01

    Highlights: • A low grade waste heat recovery system based on the concept of solar chimney is proposed. • The effects of three key factors on the system performance are examined. • Thermodynamics analysis is to find a better way to utilize low grade heat source efficiently. - Abstract: The utilization of low-temperature waste heat draws more and more attention due to serious energy crisis nowadays. This paper proposes a low-temperature waste heat recovery system based on the concept of solar chimney. In the system, low-temperature waste heat is used to heat air to produce an air updraft in the chimney tower. The air updraft propels a turbine fixed at the base of the chimney tower to convert waste heat into electricity. The mathematical model of the system is established based on first law and second law of thermodynamics. Hot water is selected as the representative of low-temperature waste heat sources for researching. The heat source temperature, ambient air temperature and area of heat transfer are examined to evaluate their effects on the system performance such as velocity of updraft, mass flow rate of air, power output, conversion efficiency, and exergy efficiency. The velocity of air demonstrates a better stability than the mass flow rate of air and the pressure difference when temperature of heat source, ambient air temperature or area of heat transfer changes

  17. Performance analysis of low temperature heat source of organic Rankine cycle for geothermal application

    Science.gov (United States)

    Pintoro, A.; Ambarita, H.; Nur, T. B.; Napitupulu, F. H.

    2018-02-01

    Indonesia has a high potential energy resources from geothermal activities. Base on the report of Asian Development Bank and World Bank, the estimated of Indonesian hydrothermal geothermal resource considered to be the largest among the world. If it’s can be utilized to produce the electric power, it’s can contribute to increasing the electrification rates in Indonesia. In this study, an experimental studied of electric power generation, utilizing the Organic Rankine Cycle (ORC) system to convert the low level heat of hydrothermal as an energy source. The temperature of hydrothermal was modelled as hot water from water boiler which has a temperature range from 60 °C - 100 °C to heat up the organic working fluid of ORC system. The system can generated 1,337.7 watts of electricity when operated using R134A with hot water inlet temperature of 100 °C. Changing system working fluid to R245fa, the net power obtained increase to 1,908.9 watts with the same heat source condition. This study showed that the ORC system can be implemented to utilize low temperature heat source of hydrothermal in Indonesia.

  18. Lithium-ion battery structure that self-heats at low temperatures

    Science.gov (United States)

    Wang, Chao-Yang; Zhang, Guangsheng; Ge, Shanhai; Xu, Terrence; Ji, Yan; Yang, Xiao-Guang; Leng, Yongjun

    2016-01-01

    Lithium-ion batteries suffer severe power loss at temperatures below zero degrees Celsius, limiting their use in applications such as electric cars in cold climates and high-altitude drones. The practical consequences of such power loss are the need for larger, more expensive battery packs to perform engine cold cranking, slow charging in cold weather, restricted regenerative braking, and reduction of vehicle cruise range by as much as 40 per cent. Previous attempts to improve the low-temperature performance of lithium-ion batteries have focused on developing additives to improve the low-temperature behaviour of electrolytes, and on externally heating and insulating the cells. Here we report a lithium-ion battery structure, the ‘all-climate battery’ cell, that heats itself up from below zero degrees Celsius without requiring external heating devices or electrolyte additives. The self-heating mechanism creates an electrochemical interface that is favourable for high discharge/charge power. We show that the internal warm-up of such a cell to zero degrees Celsius occurs within 20 seconds at minus 20 degrees Celsius and within 30 seconds at minus 30 degrees Celsius, consuming only 3.8 per cent and 5.5 per cent of cell capacity, respectively. The self-heated all-climate battery cell yields a discharge/regeneration power of 1,061/1,425 watts per kilogram at a 50 per cent state of charge and at minus 30 degrees Celsius, delivering 6.4-12.3 times the power of state-of-the-art lithium-ion cells. We expect the all-climate battery to enable engine stop-start technology capable of saving 5-10 per cent of the fuel for 80 million new vehicles manufactured every year. Given that only a small fraction of the battery energy is used for self-heating, we envisage that the all-climate battery cell may also prove useful for plug-in electric vehicles, robotics and space exploration applications.

  19. Lithium-ion battery structure that self-heats at low temperatures.

    Science.gov (United States)

    Wang, Chao-Yang; Zhang, Guangsheng; Ge, Shanhai; Xu, Terrence; Ji, Yan; Yang, Xiao-Guang; Leng, Yongjun

    2016-01-28

    Lithium-ion batteries suffer severe power loss at temperatures below zero degrees Celsius, limiting their use in applications such as electric cars in cold climates and high-altitude drones. The practical consequences of such power loss are the need for larger, more expensive battery packs to perform engine cold cranking, slow charging in cold weather, restricted regenerative braking, and reduction of vehicle cruise range by as much as 40 per cent. Previous attempts to improve the low-temperature performance of lithium-ion batteries have focused on developing additives to improve the low-temperature behaviour of electrolytes, and on externally heating and insulating the cells. Here we report a lithium-ion battery structure, the 'all-climate battery' cell, that heats itself up from below zero degrees Celsius without requiring external heating devices or electrolyte additives. The self-heating mechanism creates an electrochemical interface that is favourable for high discharge/charge power. We show that the internal warm-up of such a cell to zero degrees Celsius occurs within 20 seconds at minus 20 degrees Celsius and within 30 seconds at minus 30 degrees Celsius, consuming only 3.8 per cent and 5.5 per cent of cell capacity, respectively. The self-heated all-climate battery cell yields a discharge/regeneration power of 1,061/1,425 watts per kilogram at a 50 per cent state of charge and at minus 30 degrees Celsius, delivering 6.4-12.3 times the power of state-of-the-art lithium-ion cells. We expect the all-climate battery to enable engine stop-start technology capable of saving 5-10 per cent of the fuel for 80 million new vehicles manufactured every year. Given that only a small fraction of the battery energy is used for self-heating, we envisage that the all-climate battery cell may also prove useful for plug-in electric vehicles, robotics and space exploration applications.

  20. Exergetic evaluation of heat pump booster configurations in a low temperature district heating network

    DEFF Research Database (Denmark)

    Ommen, Torben Schmidt; Elmegaard, Brian

    2012-01-01

    In order to minimise losses in a district heating network, one approach is to lower the temperature difference between working media and soil. Considering only direct heat exchange, the minimum forward temperature level is determined by the demand side, as energy services are required at a certai...

  1. Development of low temperature solid state joining technology of dissimilar for nuclear heat exchanger tube components

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-08-15

    By conventional fusion welding process (TIG), a realization of reliable and sound joints for the nuclear heat exchanger components is very difficult, especially for the parts comprising of the dissimilar metal couples (Ti-STS, Ti-Cu alloy etc.). This is mainly attributed to the formation of brittle intermetallics (Ti{sub x}Cu{sub y}, Ti{sub x}Fe{sub y}, Ti{sub x}Ni{sub y} etc.) and wide difference in physical properties. Moreover, it usually employs very high thermal input, so making it difficult to obtain sound joints due to generations of high residual stresses and degradation of the adjacent base metals, even for similar metal combinations. In this project, the low temperature solid-state joining technology was established by developing new alloy fillers, e.g. the multi-component eutectic based alloys or amorphous alloys, and thereby lowering the joining temperature down to {approx}800 .deg. C without affecting the structural properties of base metals. Based on a low temperature joining, the interlayer engineering technology was then developed to be able to eliminate the brittleness of the joints for strong Ti-STS dissimilar joints, and the diffusion brazing technology of Ti-Ti with a superior joining strength and corrosion-resistance comparable to those of base metal were developed. By using those developed technologies, the joining procedures feasible for the heat exchanger components were finally established for the dissimilar metal joints including Ti tube sheet to super STS tube, Ti tube sheet to super STS tube sheet, and the joints of the Ti tube to Ti tube sheet

  2. Nonlinear dynamics analysis of a low-temperature-differential kinematic Stirling heat engine

    Science.gov (United States)

    Izumida, Yuki

    2018-03-01

    The low-temperature-differential (LTD) Stirling heat engine technology constitutes one of the important sustainable energy technologies. The basic question of how the rotational motion of the LTD Stirling heat engine is maintained or lost based on the temperature difference is thus a practically and physically important problem that needs to be clearly understood. Here, we approach this problem by proposing and investigating a minimal nonlinear dynamic model of an LTD kinematic Stirling heat engine. Our model is described as a driven nonlinear pendulum where the motive force is the temperature difference. The rotational state and the stationary state of the engine are described as a stable limit cycle and a stable fixed point of the dynamical equations, respectively. These two states coexist under a sufficient temperature difference, whereas the stable limit cycle does not exist under a temperature difference that is too small. Using a nonlinear bifurcation analysis, we show that the disappearance of the stable limit cycle occurs via a homoclinic bifurcation, with the temperature difference being the bifurcation parameter.

  3. The low temperature specific heat of Lu-Cu-Y metallic glasses

    International Nuclear Information System (INIS)

    Mohammed, K.A.; Lanchester, P.C.

    1987-01-01

    The specific heat of a series of amorphous metallic alloys of the form Lu x Cu 0.37 Y 0.36 (x=0, 0.1, 0.3 and 0.4) has been measured between 2 and 50 K, primarily in order to be able to determine the non-magnetic contributions to the specific heat in magnetic Re-Cu-Y amorphous alloys. The data at low temperature fit the simple form C p =γT+βT 3 from which values of γ and θ D (0) have been determined. Consideration is given to the error that arises if Y is used rather than Lu or La in forming non-magnetic rare earth intermetallics for purposes of determining the non-magnetic contributions to the specific heat of magnetic samples. A simple procedure is described that allows a useful improvement in accuracy in estimating non-magnetic contributions below 20 K if Y is used. The method may also be useful if only a restricted range of compositions using Lu is possible. (orig.)

  4. Low temperature specific heat of Lu-Cu-Y metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed, K.A.; Lanchester, P.C.

    1987-02-01

    The specific heat of a series of amorphous metallic alloys of the form Lu/sub x/Cu/sub 0.37/Y/sub 0.36/ (x=0, 0.1, 0.3 and 0.4) has been measured between 2 and 50 K, primarily in order to be able to determine the non-magnetic contributions to the specific heat in magnetic Re-Cu-Y amorphous alloys. The data at low temperature fit the simple form C/sub p/=..gamma..T+..beta..T/sup 3/ from which values of ..gamma.. and theta/sub D/(0) have been determined. Consideration is given to the error that arises if Y is used rather than Lu or La in forming non-magnetic rare earth intermetallics for purposes of determining the non-magnetic contributions to the specific heat of magnetic samples. A simple procedure is described that allows a useful improvement in accuracy in estimating non-magnetic contributions below 20 K if Y is used. The method may also be useful if only a restricted range of compositions using Lu is possible.

  5. Thermodynamic modelling of a recompression CO_2 power cycle for low temperature waste heat recovery

    International Nuclear Information System (INIS)

    Banik, Shubham; Ray, Satyaki; De, Sudipta

    2016-01-01

    Highlights: • Thermodynamic model for recompression T-CO_2 is developed. • Energetic and exergetic analysis compared with S-CO_2 and Reg. Brayton cycle. • Maximum efficiency of 13.6% is obtained for T-CO_2 cycle. • Optimum recompression ratio of 0.48 is obtained for minimum irreversibility. • Reg. Brayton has better efficiency, T-CO_2 offers minimum irreversibility. - Abstract: Due to the rising prices of conventional fossil fuels, increasing the overall thermal efficiency of a power plant is essential. One way of doing this is waste heat recovery. This recovery is most difficult for low temperature waste heat, below 240 °C, which also covers majority of the waste heat source. Carbon dioxide, with its low critical temperature and pressure, offers an advantage over ozone-depleting refrigerants used in Organic Rankine Cycles (ORCs) and hence is most suitable for the purpose. This paper introduces parametric optimization of a transcritical carbon dioxide (T-CO_2) power cycle which recompresses part of the total mass flow of working fluid before entering the precooler, thereby showing potential for higher cycle efficiency. Thermodynamic model for a recompression T-CO_2 power cycle has been developed with waste heat source of 2000 kW and at a temperature of 200 °C. Results obtained from this model are analysed to estimate effects on energetic and exergetic performances of the power cycle with varying pressure and mass recompression ratio. Higher pressure ratio always improves thermodynamic performance of the cycle – both energetic and exergetic. Higher recompression ratio also increases exergetic efficiency of the cycle. However, it increases energy efficiency, only if precooler inlet temperature remains constant. Maximum thermal efficiency of the T-CO_2 cycle with a recompression ratio of 0.26 has been found to be 13.6%. To minimize total irreversibility of the cycle, an optimum ratio of 0.48 was found to be suitable.

  6. Properties of nonstationary modes of Joule heating of a low-temperature plasma

    International Nuclear Information System (INIS)

    Rutkevich, I.M.; Sinkevich, O.A.

    1980-01-01

    The qualitative properties are investigated of the one-dimensional temperature distributions and voltage-current characteristics of a low-temperature plasma under conditions of steady-state Joule heating. The analysis is carried out for arbitrary temperature dependences of the electric conductivity sigma(T) and thermal conductivity kappa(T) (for a planar geometry). Sufficient conditions are established for uniqueness of the solution of a nonlinear boundary-value problem. The effect is studied of the relative orientation of the electric current and heat flux vectors on the properties of the solutions. Examples are constructed of N-shaped, S-shaped, and more complex voltage-current characteristics for which the uniqueness conditions are violated. The relation is studied between the temperature dependences of the true and effective electric conductivities. A qualitative difference is observed in the behavior of these quantities for a function sigma (T) having a minimum. The inverse problem is considered of determining the functions sigma(T) and kappa(T) from data of electrical measurements. The role is discussed of the finite value of the thermal resistance of the walls in the generation of nonmonotone voltage-current characteristics

  7. A combined power cycle utilizing low-temperature waste heat and LNG cold energy

    International Nuclear Information System (INIS)

    Shi Xiaojun; Che Defu

    2009-01-01

    This paper has proposed a combined power system, in which low-temperature waste heat can be efficiently recovered and cold energy of liquefied natural gas (LNG) can be fully utilized as well. This system consists of an ammonia-water mixture Rankine cycle and an LNG power generation cycle, and it is modelled by considering mass, energy and species balances for every component and thermodynamic analyses are conducted. The results show that the proposed combined cycle has good performance, with net electrical efficiency and exergy efficiency of 33% and 48%, respectively, for a typical operating condition. The power output is equal to 1.25 MWh per kg of ammonia-water mixture. About 0.2 MW of electrical power for operating sea water pumps can be saved. Parametric analyses are performed for the proposed combined cycle to evaluate the effects of key factors on the performance of the proposed combined cycle through simulation calculations. Results show that a maximum net electrical efficiency can be obtained as the inlet pressure of ammonia turbine increases and the peak value increases as the ammonia mass fraction increases. Exergy efficiency goes up with the increased ammonia turbine inlet pressure. With the ammonia mass fraction increases, the net electrical efficiency increases, whereas exergy efficiency decreases. For increasing LNG turbine inlet pressure or heat source temperature, there is also a peak of net electrical efficiency and exergy efficiency. With the increase of LNG gas turbine outlet pressure, exergy efficiency increases while net electrical efficiency drops

  8. Low temperature heat source for power generation: Exhaustive analysis of a carbon dioxide transcritical power cycle

    International Nuclear Information System (INIS)

    Velez, Fredy; Segovia, Jose; Chejne, Farid; Antolin, Gregorio; Quijano, Ana; Carmen Martin, M.

    2011-01-01

    The main results of a theoretical work on the use of a low temperature heat source for power generation through a carbon dioxide transcritical power cycle are reported in this paper. The procedure for analyzing the behaviour of the proposed cycle consisted in modifying the input pressure to the turbine from 66 bar, maintained constant each evaluated temperature (60 o C, 90 o C, 120 o C and 150 o C) until the net work was approximately zero. As a result, the maximum exergy efficiency was 50%, while the energy efficiencies obtained were 9.8%, 7.3%, 4.9% and 2.4% and the net specific work was 18.2 kJ/kg, 12.8 kJ/kg, 7.8 kJ/kg and 3.5 kJ/kg, respectively. Furthermore, the effect of the addition of an internal heat exchanger, which obviously supposed an increase in the efficiency, was analyzed. The analysis of the proposed system shows the viability of implementing this type of process as an energy alternative and/or strengthener of non-conventional energy sources in non-provided zones, or for increasing the energy efficiency in the industry. -- Highlights: → Energy and exergy analysis of a carbon dioxide transcritical power cycle is reported. → The effect of the inlet temperature to the turbine is evaluated. → Conditions of maximum efficiency and maximum net work are compared. → The inclusion of an IHX is also analysed.

  9. Heat and Mass Transfer in a High-Porous Low-Temperature Thermal Insulation in Real Operating Conditions

    Directory of Open Access Journals (Sweden)

    Polovnikov Vyacheslav Yu.

    2015-01-01

    Full Text Available The results of numerical simulation of heat and mass transfer in a high-porous low-temperature insulation in conditions of insulation freezing, a moisture migration to the front of phase transition and a condensation forming on an outer contour of interaction were obtained. Values of heat leakage were established.

  10. Application and microbial ecology of psychrotrophs in domestic wastewater treatment at low temperature.

    Science.gov (United States)

    Xu, Zhenzhen; Ben, Yue; Chen, Zhonglin; Jiang, Anxi; Shen, Jimin; Han, Xiaoyun

    2018-01-01

    The feasibility of a bunch of screened psychrotrophs being applied to low-temperature wastewater treatment was investigated. The screened psychrophillic strains are capable of growth at a broad temperature-range from 0 to 40 °C and exhibit a preferable TTC-dehydrogenase activity at low temperature (4-10 °C). Along the sharply fluctuant temperatures (25-4-25 °C), the screened psychrotrophs (compared with the indigenous mesophiles) demonstrate less fluctuations of COD removal and more rapid recovery after temperature shocks. COD removal of approximate 80% was recorded by single psychrotrophs (while only 10% by single mesophiles) at low temperature (4 °C). Soft polyurethane foam showed better performance for psychrotrophs immobilization, with the optimal filling rate of 30% (v/v) in the bioreactor. The observation shows that the immobilized psychrotrophs demonstrated a relatively high performance on both conventional and emerging organic contaminants removals at low temperature. In order to check the feasibility of the screened psychrotrophs in treating actual domestic wastewater, a pilot-scale ICABR bioreactor was operated firstly at low temperature (4 °C) and then at seasonal varying temperatures (0-30 °C) for one year, the influent COD of 150-600 mg L -1 was efficiently reduced to 40 ± 18 mg L -1 under the conditions of an overall hydraulic retention time of 10 h. Furthermore, psychrotrophs performed stably as the predominant bacteria family during the whole operation. This study provides evidence that microbial intensification with psychrotrophs was a feasible strategy to improve the efficiency of conventional wastewater treatment process at low temperature. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. A renewable energy scenario for Aalborg Municipality based on low-temperature geothermal heat, wind power and biomass

    DEFF Research Database (Denmark)

    Østergaard, Poul Alberg; Mathiesen, Brian Vad; Möller, Bernd

    2010-01-01

    Aalborg Municipality, Denmark, wishes to investigate the possibilities of becoming independent of fossil fuels. This article describes a scenario for supplying Aalborg Municipality’s energy needs through a combination of low-temperature geothermal heat, wind power and biomass. Of particular focus...... in the scenario is how low-temperature geothermal heat may be utilised in district heating (DH) systems. The analyses show that it is possible to cover Aalborg Municipality’s energy needs through the use of locally available sources in combination with significant electricity savings, heat savings, reductions...... in industrial fuel use and savings and fuel-substitutions in the transport sector. With biomass resources being finite, the two marginal energy resources in Aalborg are geothermal heat and wind power. If geothermal heat is utilised more, wind power may be limited and vice versa. The system still relies...

  12. Thermochemical Characterizations of Novel Vermiculite-LiCl Composite Sorbents for Low-Temperature Heat Storage

    Directory of Open Access Journals (Sweden)

    Yannan Zhang

    2016-10-01

    Full Text Available To store low-temperature heat below 100 °C, novel composite sorbents were developed by impregnating LiCl into expanded vermiculite (EVM in this study. Five kinds of composite sorbents were prepared using different salt concentrations, and the optimal sorbent for application was selected by comparing both the sorption characteristics and energy storage density. Textural properties of composite sorbents were obtained by extreme-resolution field emission scanning electron microscopy (ER-SEM and an automatic mercury porosimeter. After excluding two composite sorbents which would possibly exhibit solution leakage in practical thermal energy storage (TES system, thermochemical characterizations were implemented through simulative sorption experiments at 30 °C and 60% RH. Analyses of thermogravimetric analysis/differential scanning calorimetry (TGA/DSC curves indicate that water uptake of EVM/LiCl composite sorbents is divided into three parts: physical adsorption of EVM, chemical adsorption of LiCl crystal, and liquid–gas absorption of LiCl solution. Energy storage potential was evaluated by theoretical calculation based on TGA/DSC curves. Overall, EVMLiCl20 was selected as the optimal composite sorbent with water uptake of 1.41 g/g, mass energy storage density of 1.21 kWh/kg, and volume energy storage density of 171.61 kWh/m3.

  13. Sclerotial formation of Polyporus umbellatus by low temperature treatment under artificial conditions.

    Science.gov (United States)

    Xing, Yong-Mei; Zhang, Li-Chun; Liang, Han-Qiao; Lv, Jing; Song, Chao; Guo, Shun-Xing; Wang, Chun-Lan; Lee, Tae-Soo; Lee, Min-Woong

    2013-01-01

    Polyporus umbellatus sclerotia have been used as a diuretic agent in China for over two thousand years. A shortage of the natural P. umbellatus has prompted researchers to induce sclerotial formation in the laboratory. P. umbellatus cultivation in a sawdust-based substrate was investigated to evaluate the effect of low temperature conditions on sclerotial formation. A phenol-sulfuric acid method was employed to determine the polysaccharide content of wild P. umbellatus sclerotia and mycelia and sclerotia grown in low-temperature treatments. In addition, reactive oxygen species (ROS) content, expressed as the fluorescence intensity of mycelia during sclerotial differentiation was determined. Analysis of ROS generation and sclerotial formation in mycelia after treatment with the antioxidants such as diphenyleneiodonium chloride (DPI), apocynin (Apo), or vitamin C were studied. Furthermore, macroscopic and microscopic characteristics of sclerotial differentiation were observed. Sclerotia were not induced by continuous cultivation at 25°C. The polysaccharide content of the artificial sclerotia is 78% of that of wild sclerotia. In the low-temperature treatment group, the fluorescent intensity of ROS was higher than that of the room temperature (25°C) group which did not induce sclerotial formation all through the cultivation. The antioxidants DPI and Apo reduced ROS levels and did not induce sclerotial formation. Although the concentration-dependent effects of vitamin C (5-15 mg mL(-1)) also reduced ROS generation and inhibited sclerotial formation, using a low concentration of vitamin C (1 mg mL(-1)) successfully induced sclerotial differentiation and increased ROS production. Exposure to low temperatures induced P. umbellatus sclerotial morphogenesis during cultivation. Low temperature treatment enhanced ROS in mycelia, which may be important in triggering sclerotial differentiation in P. umbellatus. Moreover, the application of antioxidants impaired ROS generation

  14. Comparison of shell-and-tube with plate heat exchangers for the use in low-temperature organic Rankine cycles

    International Nuclear Information System (INIS)

    Walraven, Daniël; Laenen, Ben; D’haeseleer, William

    2014-01-01

    Highlights: • Binary cycles for low-temperature heat sources are investigated. • Shell-and-tube and plate heat exchangers are modeled. • System optimization of the cycle variables and heat exchanger geometry. • ORCs with plate heat exchangers obtain in most cases higher efficiencies. - Abstract: Organic Rankine cycles (ORCs) can be used for electricity production from low-temperature heat sources. These ORCs are often designed based on experience, but this experience will not always lead to the most optimal configuration. The ultimate goal is to design ORCs by performing a system optimization. In such an optimization, the configuration of the components and the cycle parameters (temperatures, pressures, mass flow rate) are optimized together to obtain the optimal configuration of power plant and components. In this paper, the configuration of plate heat exchangers or shell-and-tube heat exchangers is optimized together with the cycle configuration. In this way every heat exchanger has the optimum allocation of heat exchanger surface, pressure drop and pinch-point-temperature difference for the given boundary conditions. ORCs with plate heat exchangers perform mostly better than ORCs with shell-and-tube heat exchangers, but one disadvantage of plate heat exchangers is that the geometry of both sides is the same, which can result in an inefficient heat exchanger. It is also shown that especially the cooling-fluid inlet temperature and mass flow have a strong influence on the performance of the power plant

  15. Effect of low temperature oxygen plasma treatment on microstructure and adhesion force of graphene

    Science.gov (United States)

    Zhu, Jun; Deng, Heijun; Xue, Wei; Wang, Quan

    2018-01-01

    Graphene has attracted strong attention due to its unique mechanical, electrical, thermal and magnetic properties. In this work, we investigate the effect of low temperature oxygen plasma treatment on microstructure and adhesion force of single-layer graphene (SLG). Low temperature oxygen plasma is used to treat SLG grown by chemical vapor deposition through varying the exposure time. Raman spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy are utilized to identify changes before and after treatment. Raman spectra of treated graphene reveal that peak intensity of the characteristic D and D' peaks increase. Meanwhile, degradation of the G and 2D peaks in X-ray photoelectron spectroscopy indicates that abundant Csbnd OH and Cdbnd O functional groups are introduced into graphene after treatment. AFM investigation shows that surface roughness and adhesion force of treated graphene increase significantly firstly and then slowly. Therefore, this work would offer a practical route to improve the performance of graphene-based devices.

  16. Changes in heat load profile of typical Danish multi-storey buildings when energy-renovated and supplied with low-temperature district heating

    DEFF Research Database (Denmark)

    Harrestrup, Maria; Svendsen, Svend

    2013-01-01

    end-use savings are implemented in buildings concurrent with the application of low-temperature district heating (LTDH), the heat profiles of the buildings will change. Reducing peak loads is important, since this is the dimensioning foundation for future district heating systems. To avoid oversized...

  17. A Low Temperature Detoxification Method for Treatment of Chrysotile-Containing Waste Roofing Slate

    Directory of Open Access Journals (Sweden)

    Hwanju Jo

    2017-08-01

    Full Text Available In this study, we evaluated a two-step process for detoxification of waste roofing slate, involving cement hydrate removal and low temperature detoxification using oxalic acid. These treatments were conducted on raw material and intermediate product, respectively. Cement hydrate removal effectively eliminated most Ca-containing cement hydrate components from the raw material under the following conditions: HCl to solid ratio: 0.456 g/g, reaction time: 2 h, and solid to liquid ratio: 0.124 g/mL. Following low temperature (~100 °C detoxification of intermediate product obtained after cement hydrate removal, chrysotile in waste roofing slate was effectively transformed to Mg-oxalate under conditions of oxalic acid to solid ratio of >0.67 g/g.

  18. Modelling and multi-scenario analysis for electric heat tracing system combined with low temperature district heating for domestic hot water supply

    DEFF Research Database (Denmark)

    Yang, Xiaochen; Li, Hongwei; Svendsen, Svend

    2016-01-01

    Low temperature district heating (LTDH) is a cost-efficient way of supplying space heating and domestic hot water (DHW) for buildings in urban areas. However, there is concern that the potential hygiene problems (Legionella) might occur if LTDH is implemented, especially for large buildings...... performance on heat loss saving, and it also gave benefits to district heating network by sharing part of the heating load....

  19. Numerical Simulation of Pulsation Flow in the Vapour Channel of Short Low Temperature Heat Pipes at High Heat Loads

    Science.gov (United States)

    Seryakov, A. V.; Konkin, A. V.

    2017-11-01

    The results of the numerical simulation of pulsations in the Laval-liked vapour channel of short low-temperature range heat pipes (HPs) are presented. The numerical results confirmed the experimentally obtained increase of the frequency of pulsations in the vapour channel of short HPs with increasing overheat of the porous evaporator relative to the boiling point of the working fluid. The occurrence of pressure pulsations inside the vapour channel in a short HPs is a complex phenomenon associated with the boiling beginning in the capillary-porous evaporator at high heat loads, and appearance the excess amount of vapour above it, leading to the increase in pressure P to a value at which the boiling point TB of the working fluid becomes higher than the evaporator temperature Tev. Vapour clot spreads through the vapour channel and condense, and then a rarefaction wave return from condenser in the evaporator, the boiling in which is resumed and the next cycle of the pulsations is repeated. Numerical simulation was performed using finite element method implemented in the commercial program ANSYS Multiphisics 14.5 in the two-dimensional setting of axis symmetric moist vapour flow with third kind boundary conditions.

  20. Enrichment of denitrifying methanotrophic bacteria for application after direct low-temperature anaerobic sewage treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kampman, Christel, E-mail: christel.kampman@wur.nl [Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA, Wageningen (Netherlands); Hendrickx, Tim L.G. [Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA, Wageningen (Netherlands); Luesken, Francisca A.; Alen, Theo A. van; Op den Camp, Huub J.M.; Jetten, Mike S.M. [Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands); Zeeman, Grietje; Buisman, Cees J.N.; Temmink, Hardy [Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA, Wageningen (Netherlands)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer A new concept for low-temperature anaerobic sewage treatment is proposed. Black-Right-Pointing-Pointer In this concept, denitrification and methane oxidation are performed by Methylomirabilis oxyfera. Black-Right-Pointing-Pointer The bacteria were enriched from fresh water sediment using sequencing fed-batch reactors. Black-Right-Pointing-Pointer The volumetric consumption rate has to be increased by an order of magnitude for practical application. Black-Right-Pointing-Pointer Further research should focus on systems with improved biomass retention. - Abstract: Despite many advantages of anaerobic sewage treatment over conventional activated sludge treatment, it has not yet been applied in temperate zones. This is especially because effluent from low-temperature anaerobic treatment contains nitrogen and dissolved methane. The presence of nitrogen and methane offers the opportunity to develop a reactor in which methane is used as electron donor for denitrification. Such a reactor could be used in a new concept for low-temperature anaerobic sewage treatment, consisting of a UASB-digester system, a reactor for denitrification coupled to anaerobic methane oxidation, and a nitritation reactor. In the present study denitrifying methanotrophic bacteria similar to 'Candidatus Methylomirabilis oxyfera' were enriched. Maximum volumetric nitrite consumption rates were 33.5 mg NO{sub 2}{sup -}-N/L d (using synthetic medium) and 37.8 mg NO{sub 2}{sup -}-N/L d (using medium containing effluent from a sewage treatment plant), which are similar to the maximum rate reported so far. Though the goal was to increase the rates, in both reactors, after reaching these maximum rates, volumetric nitrite consumption rates decreased in time. Results indicate biomass washout may have significantly decelerated enrichment. Therefore, to obtain higher volumetric consumption rates, further research should focus on systems with complete biomass

  1. Enrichment of denitrifying methanotrophic bacteria for application after direct low-temperature anaerobic sewage treatment

    International Nuclear Information System (INIS)

    Kampman, Christel; Hendrickx, Tim L.G.; Luesken, Francisca A.; Alen, Theo A. van; Op den Camp, Huub J.M.; Jetten, Mike S.M.; Zeeman, Grietje; Buisman, Cees J.N.; Temmink, Hardy

    2012-01-01

    Highlights: ► A new concept for low-temperature anaerobic sewage treatment is proposed. ► In this concept, denitrification and methane oxidation are performed by Methylomirabilis oxyfera. ► The bacteria were enriched from fresh water sediment using sequencing fed-batch reactors. ► The volumetric consumption rate has to be increased by an order of magnitude for practical application. ► Further research should focus on systems with improved biomass retention. - Abstract: Despite many advantages of anaerobic sewage treatment over conventional activated sludge treatment, it has not yet been applied in temperate zones. This is especially because effluent from low-temperature anaerobic treatment contains nitrogen and dissolved methane. The presence of nitrogen and methane offers the opportunity to develop a reactor in which methane is used as electron donor for denitrification. Such a reactor could be used in a new concept for low-temperature anaerobic sewage treatment, consisting of a UASB-digester system, a reactor for denitrification coupled to anaerobic methane oxidation, and a nitritation reactor. In the present study denitrifying methanotrophic bacteria similar to ‘Candidatus Methylomirabilis oxyfera’ were enriched. Maximum volumetric nitrite consumption rates were 33.5 mg NO 2 − -N/L d (using synthetic medium) and 37.8 mg NO 2 − -N/L d (using medium containing effluent from a sewage treatment plant), which are similar to the maximum rate reported so far. Though the goal was to increase the rates, in both reactors, after reaching these maximum rates, volumetric nitrite consumption rates decreased in time. Results indicate biomass washout may have significantly decelerated enrichment. Therefore, to obtain higher volumetric consumption rates, further research should focus on systems with complete biomass retention.

  2. Metallurgical study of low-temperature plasma carbon diffusion treatments for stainless steels

    International Nuclear Information System (INIS)

    Lewis, D.B.; Leyland, A.; Stevenson, P.R.; Cawley, J.; Matthews, A.

    1993-01-01

    We recently reported a novel low-temperature carbon diffusion technique for surface hardening of stainless steels. The treatment was shown to provide benefits in terms of abrasive wear resistance. There is also evidence to suggest that by performing diffusion treatments at low temperatures (i.e. below 400 C), these benefits can be achieved without compromising corrosion resistance. Here a variety of surface analysis and depth profiling techniques have been used to determine the physical and mechanical properties of carbon-rich layers produced on a range of stainless steel substrate materials. X-ray diffraction (XRD) was employed to determine the crystallographic structure, whilst wavelength dispersive X-ray analysis (WDX) and glow discharge optical spectroscopy (GDOS) gave information on the concentration and distribution of the diffused species within the treated layers. A variety of carbide-based structures was detected, including the expected M 23 C 6 and, more surprisingly, M 3 C. Optical and electron microscopy techniques were used to provide information on layer morphology. The surfaces produced by the low-temperature carbon-diffusion process generally exhibit a distinct diffusion layer of between 1 and 20 μm, depending on the material and the treatment conditions. Austenitic stainless steels appear to give the best response to treatment, however other types of stainless steel can be treated, particularly if the microstructure contains above 5% retained austenite. Here we discuss the changes in mechanical and metallurgical properties provided by this technique and its potential value for treatment of both austenitic and other stainless steel substrate materials. (orig.)

  3. Comparison of LCA results of low temperature heat plant using electric heat pump, absorption heat pump and gas-fired boiler

    International Nuclear Information System (INIS)

    Nitkiewicz, Anna; Sekret, Robert

    2014-01-01

    Highlights: • Usage of geothermal heat pump can bring environmental benefits. • The lowest environmental impact for whole life cycle is obtained for absorption heat pump. • The value of heat pump COP has a significant influence on environmental impact. • In case of coal based power generation the damage to human health is significant. - Abstract: This study compares the life cycle impacts of three heating plant systems which differ in their source of energy and the type of system. The following heating systems are considered: electric water-water heat pump, absorption water-water heat pump and natural gas fired boiler. The heat source for heat pump systems is low temperature geothermal source with temperature below 20 °C and spontaneous outflow 24 m 3 /h. It is assumed that the heat pumps and boiler are working in monovalent system. The analysis was carried out for heat networks temperature characteristic at 50/40 °C which is changing with outdoor temperature during heating season. The environmental life cycle impact is evaluated within life cycle assessment methodological framework. The method used for life cycle assessment is eco-indicator ‘99. The functional unit is defined as heating plant system with given amount of heat to be delivered to meet local heat demand in assumed average season. The data describing heating plant system is derived from literature and energy analysis of these systems. The data describing the preceding life cycle phases: extraction of raw materials and fuels, production of heating devices and their transportation is taken from Ecoinvent 2.0 life cycle inventory database. The results were analyzed on three levels of indicators: single score indicator, damage category indicators and impact category indicator. The indicators were calculated for characterization, normalization and weighting phases as well. SimaPro 7.3.2 is the software used to model the systems’ life cycle. The study shows that heating plants using a low

  4. Relationship between low-temperature boson heat capacity peak and high-temperature shear modulus relaxation in a metallic glass

    International Nuclear Information System (INIS)

    Vasiliev, A. N.; Voloshok, T. N.; Granato, A. V.; Joncich, D. M.; Mitrofanov, Yu. P.; Khonik, V. A.

    2009-01-01

    Low-temperature (2 K≤T≤350 K) heat capacity and room-temperature shear modulus measurements (ν=1.4 MHz) have been performed on bulk Pd 41.25 Cu 41.25 P 17.5 in the initial glassy, relaxed glassy, and crystallized states. It has been found that the height of the low-temperature Boson heat capacity peak strongly correlates with the changes in the shear modulus upon high-temperature annealing. It is this behavior that was earlier predicted by the interstitialcy theory, according to which dumbbell interstitialcy defects are responsible for a number of thermodynamic and kinetic properties of crystalline, (supercooled) liquid, and solid glassy states.

  5. Low Temperature Graphene Synthesis from Poly(methyl methacrylate) Using Microwave Plasma Treatment

    Science.gov (United States)

    Yamada, Takatoshi; Ishihara, Masatou; Hasegawa, Masataka

    2013-11-01

    A graphene film having low sheet resistance (600 Ω/sq.) was synthesized at low temperatures of 280 °C. Utilizing microwave plasma treatment, graphene films were synthesized from a solid phase on a copper surface. The full width at half maximum of the 2D-band in the Raman spectrum indicated that a high quality graphene film was formed. Cross-sectional transmission electron microscopy observation revealed that the deposited graphene films consisted of single- or double-layer graphene flakes of nanometer order on the Cu surface, which agrees with the estimated number of layers from an average optical transmittance of 96%.

  6. Technical assessment of electric heat boosters in low-temperature district heating based on combined heat and power analysis

    DEFF Research Database (Denmark)

    Cai, Hanmin; You, Shi; Wang, Jiawei

    2018-01-01

    This paper provides a technical assessment of electric heat boosters (EHBs) in low-energy districts. The analysis is based on a hypothetical district with 23 terraced single-family houses supplied by both a lowtemperature district heating (LTDH) network and a low-voltage network (LVN). Two case...

  7. Magnetic hyperthermia heating of cobalt ferrite nanoparticles prepared by low temperature ferrous sulfate based method

    Directory of Open Access Journals (Sweden)

    Tejabhiram Yadavalli

    2016-05-01

    Full Text Available A facile low temperature co-precipitation method for the synthesis of crystalline cobalt ferrite nanostructures using ferrous sulfate salt as the precursor has been discussed. The prepared samples were compared with nanoparticles prepared by conventional co-precipitation and hydrothermal methods using ferric nitrate as the precursor. X-ray diffraction studies confirmed the formation of cubic spinel cobalt ferrites when dried at 110 °C as opposed to conventional methods which required higher temperatures/pressure for the formation of the same. Field emission scanning electron microscope studies of these powders revealed the formation of nearly spherical nanostructures in the size range of 20-30 nm which were comparable to those prepared by conventional methods. Magnetic measurements confirmed the ferromagnetic nature of the cobalt ferrites with low magnetic remanance. Further magnetic hyperthermia studies of nanostructures prepared by low temperature method showed a rise in temperature to 50 °C in 600 s.

  8. Heat-equilibrium low-temperature plasma decay in synthesis of ammonia via transient components N2H6

    International Nuclear Information System (INIS)

    Cao Guobin; Song Youqun; Chen Qing; Zhou Qiulan; Cao Yun; Wang Chunhe

    2001-01-01

    The author introduced a new method of heat-equilibrium low-temperature plasma in ammonia synthesis and a technique of continuous real-time inlet sampling mass-spectrometry to detect the reaction channel and step of the decay of transient component N 2 H 6 into ammonia. The experimental results indicated that in the process of ammonia synthesis by discharge of N 2 and H 2 mixture, the transient component N 2 H 6 is a necessary step

  9. Improved design for a low temperature scanning tunneling microscope with an in situ tip treatment stage.

    Science.gov (United States)

    Kim, J-J; Joo, S H; Lee, K S; Yoo, J H; Park, M S; Kwak, J S; Lee, Jinho

    2017-04-01

    The Low Temperature Scanning Tunneling Microscope (LT-STM) is an extremely valuable tool not only in surface science but also in condensed matter physics. For years, numerous new ideas have been adopted to perfect LT-STM performances-Ultra-Low Vibration (ULV) laboratory and the rigid STM head design are among them. Here, we present three improvements for the design of the ULV laboratory and the LT-STM: tip treatment stage, sample cleaving stage, and vibration isolation system. The improved tip treatment stage enables us to perform field emission for the purpose of tip treatment in situ without exchanging samples, while our enhanced sample cleaving stage allows us to cleave samples at low temperature in a vacuum without optical access by a simple pressing motion. Our newly designed vibration isolation system provides efficient space usage while maintaining vibration isolation capability. These improvements enhance the quality of spectroscopic imaging experiments that can last for many days and provide increased data yield, which we expect can be indispensable elements in future LT-STM designs.

  10. Low Temperature Refrigeration as an Alternative Anti-Pest Treatment of Dates

    Science.gov (United States)

    Lallouche, Ahmed; Kolodyaznaya, Valentina; Boulkrane, Mohamed Said; Baranenko, Denis

    2017-11-01

    Large amounts of dates are produced and consumed around the world each year. Apomyelois ceratoniae causes main losses during storage and export of date fruit. Fumigation is the most widely used treatment to prevent postharvest losses. However, this treatment negatively affects the biological value of dates, environmental and economic parameters of production. Widespread fumigation agent methyl bromide is toxic to a human body and contributes to the destruction of the ozone layer. The aim of the current work was to find a new method based on the use of low temperature refrigeration to reduce the pest and insect infestation preserving the nutritive value of dates during cold storage at the same time. A. ceratoniae mortality under different temperatures and dates respiration rate, sugar, organic acids, pectic substances content and sensorial characteristics were studied. The results indicate that at -18 °C the A. ceratonie larva dies within 2 h, the eggs and larvae - within 24 h respectively. Thus, it is clearly shown that there is no need in using chemicals or irradiation to prevent dates pests. Physicochemical and organoleptic proprieties of dates were satisfactory during 360 d at -18 °C and during 180 d at +4 °C. The low temperature refrigeration and storage at -18 °C is recommended for dates to prevent pests and quality losses. It is apparently advantageous for environment and climate if compared with other anti-pest treatment variants.

  11. Performance analysis of ORC power generation system with low-temperature waste heat of aluminum reduction cell

    Science.gov (United States)

    Wang, Zhiqi; Zhou, Naijun; Jing, Guo

    Performance of organic Rankine cycle (ORC) system to recover low-temperature waste heat from aluminum reduction cell was analyzed. The temperature of waste heat is 80°C-200°C and the flow rate is 3×105m3/h. The pinch temperature difference between waste heat and working fluids is 10°C. The results show that there is optimal evaporating temperature for maximum net power under the same pinch point. For heat source temperature range of 80°C-140°C and 150°C-170°C, the working fluid given biggest net power is R227ea and R236fa, respectively. When the temperature is higher than 180°C, R236ea generates the biggest net power. The variation of heat source temperature has important effect on net power. When the temperature decreases 10%, the net power will deviate 30% from the maximum value.

  12. UV excimer laser and low temperature plasma treatments of polyamide materials

    Science.gov (United States)

    Yip, Yiu Wan Joanne

    Polyamides have found widespread application in various industrial sectors, for example, they are used in apparel, home furnishings and similar uses. However, the requirements for high quality performance products are continually increasing and these promote a variety of surface treatments for polymer modification. UV excimer laser and low temperature plasma treatments are ideally suited for polyamide modification because they can change the physical and chemical properties of the material without affecting its bulk features. This project aimed to study the modification of polyamides by UV excimer laser irradiation and low temperature plasma treatment. The morphological changes in the resulting samples were analysed by scanning electron microscopy (SEM) and tapping mode atomic force microscopy (TM-AFM). The chemical modifications were studied by x-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and chemical force microscopy (CFM). Change in degree of crystallinity was examined by differential scanning calorimetry (DSC). After high-fluence laser irradiation, topographical results showed that ripples of micrometer size form on the fibre surface. By contrast, sub-micrometer size structures form on the polyamide surface when the applied laser energy is well below its ablation threshold. After high-fluence laser irradiation, chemical studies showed that the surface oxygen content of polyamide is reduced. A reverse result is obtained with low-fluence treatment. The DSC result showed no significant change in degree of crystallinity in either high-fluence or low-fluence treated samples. The same modifications in polyamide surfaces were studied after low temperature plasma treatment with oxygen, argon or tetrafluoromethane gas. The most significant result was that the surface oxygen content of polyamide increased after oxygen and argon plasma treatments. Both treatments induced many hydroxyl (-OH) and carboxylic acid (-COOH

  13. Surface Damage and Treatment by Impact of a Low Temperature Nitrogen Jet

    Science.gov (United States)

    Laribou, Hicham; Fressengeas, Claude; Entemeyer, Denis; Jeanclaude, Véronique; Tazibt, Abdel

    2011-01-01

    Nitrogen jets under high pressure and low temperature have been introduced recently. The process consists in projecting onto a surface a low temperature jet obtained from releasing the liquid nitrogen stored in a high pressure tank (e.g. 3000 bars) through a nozzle. It can be used in a range of industrial applications, including surface treatment or material removal through cutting, drilling, striping and cleaning. The process does not generate waste other than the removed matter, and it only releases neutral gas into the atmosphere. This work is aimed at understanding the mechanisms of the interaction between the jet and the material surface. Depending on the impacted material, the thermo-mechanical shock and blast effect induced by the jet can activate a wide range of damage mechanisms, including cleavage, crack nucleation and spalling, as well as void expansion and localized ductile failure. The test parameters (standoff distance, dwell time, operating pressure) play a role in selecting the dominant damage mechanism, but combinations of these various modes are usually present. Surface treatment through phase transformation or grain fragmentation in a layer below the surface can also be obtained by adequate tuning of the process parameters. In the current study, work is undertaken to map the damage mechanisms in metallic materials as well as the influence of the test parameters on damage, along with measurements of the thermo-mechanical conditions (impact force, temperature) in the impacted area.

  14. District space heating potential of low temperature hydrothermal geothermal resources in the southwestern United States. Technical report

    Energy Technology Data Exchange (ETDEWEB)

    McDevitt, P.K.; Rao, C.R.

    1978-10-01

    A computer simulation model (GIRORA-Nonelectric) is developed to study the economics of district space heating using geothermal energy. GIRORA-Nonelectric is a discounted cashflow investment model which evaluates the financial return on investment for space heating. This model consists of two major submodels: the exploration for and development of a geothermal anomaly by a geothermal producer, and the purchase of geothermal fluid by a district heating unit. The primary output of the model is a calculated rate of return on investment earned by the geothermal producer. The results of the sensitivity analysis of the model subject to changes in physical and economic parameters are given in this report. Using the results of the economic analysis and technological screening criteria, all the low temperature geothermal sites in Southwestern United States are examined for economic viability for space heating application. The methodology adopted and the results are given.

  15. Design of passive decay heat removal system using thermosyphon for low temperature and low pressure pool type LWR

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Jangsik; You, Byung Hyun; Jung, Yong Hun; Jeong, Yong Hoon [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2013-10-15

    In seawater desalination process which doesn't need high temperature steam, the reactor has profitability. KAIST has be developing the new reactor design, AHR400, for only desalination. For maximizing safety, the reactor requires passive decay heat removal system. In many nuclear reactors, DHR system is loop form. The DHR system can be designed simple by applying conventional thermosyphon, which is fully passive device, shows high heat transfer performance and simple structure. DHR system utilizes conventional thermosyphon and its heat transfer characteristics are analyzed for AHR400. For maximizing safety of the reactor, passive decay heat removal system are prepared. Thermosyphon is useful device for DHR system of low pressure and low temperature pool type reactor. Thermosyphon is operated fully passive and has simple structure. Bundle of thermosyphon get the goal to prohibit boiling in reactor and high pressure in reactor vessel.

  16. Recuperator with microjet technology as a proposal for heat recovery from low-temperature sources

    Directory of Open Access Journals (Sweden)

    Wajs Jan

    2015-12-01

    Full Text Available A tendency to increase the importance of so-called dispersed generation, based on the local energy sources and the working systems utilizing both the fossil fuels and the renewable energy resources is observed nowadays. Generation of electricity on industrial or domestic scale together with production of heat can be obtained for example through employment of the ORC systems. It is mentioned in the EU directive 2012/27/EU for cogenerative production of heat and electricity. For such systems the crucial points are connected with the heat exchangers, which should be small in size but be able to transfer high heat fluxes. In presented paper the prototype microjet heat exchanger dedicated for heat recovery systems is introduced. Its novel construction is described together with the systematical experimental analysis of heat transfer and flow characteristics. Reported results showed high values of the overall heat transfer coefficient and slight increase in the pressure drop. The results of microjet heat exchanger were compared with the results of commercially available compact plate heat exchanger.

  17. Recuperator with microjet technology as a proposal for heat recovery from low-temperature sources

    Science.gov (United States)

    Wajs, Jan; Mikielewicz, Dariusz; Fornalik-Wajs, Elżbieta; Bajor, Michał

    2015-12-01

    A tendency to increase the importance of so-called dispersed generation, based on the local energy sources and the working systems utilizing both the fossil fuels and the renewable energy resources is observed nowadays. Generation of electricity on industrial or domestic scale together with production of heat can be obtained for example through employment of the ORC systems. It is mentioned in the EU directive 2012/27/EU for cogenerative production of heat and electricity. For such systems the crucial points are connected with the heat exchangers, which should be small in size but be able to transfer high heat fluxes. In presented paper the prototype microjet heat exchanger dedicated for heat recovery systems is introduced. Its novel construction is described together with the systematical experimental analysis of heat transfer and flow characteristics. Reported results showed high values of the overall heat transfer coefficient and slight increase in the pressure drop. The results of microjet heat exchanger were compared with the results of commercially available compact plate heat exchanger.

  18. A system design for distributed energy generation in low temperature district heating (LTDH) networks

    OpenAIRE

    Jones, Sean; Gillott, Mark C.; Boukhanouf, Rabah; Walker, Gavin S.; Tunzi, Michele; Tetlow, David; Rodrigues, Lucélia Taranto; Sumner, M.

    2017-01-01

    Project SCENIC (Smart Controlled Energy Networks Integrated in Communities) involves connecting properties at the University of Nottingham’s Creative Energy Homes test site in a community scale, integrated heat and power network. Controls will be developed to allow for the most effective heat load allocation and power distribution scenarios. Furthermore, the system will develop the prosumer concept, where consumers are both buyers and sellers of energy in both heat and power systems. \\ud \\ud ...

  19. Parametric Analysis of the feasibility of low-temperature geothermal heat recovery in sedimentary basins

    Science.gov (United States)

    Tomac, I.; Caulk, R.

    2016-12-01

    The current study explored the feasibility of heat recovery through the installation of heat exchangers in abandoned oil and gas wells. Finite Element Methods (FEM) were employed to determine the effects of various site specific parameters on production fluid temperature. Specifically, the study parameterized depth of well, subsurface temperature gradient, sedimentary rock conductivity, and flow rate. Results show that greater well depth is associated with greater heat flow, with the greatest returns occurring between depths of 1.5 km and 7 km. Beyond 7 km, the rate of return decreases due to a non-linear increase of heat flow combined with a continued linear increase of pumping cost. One cause for the drop of heat flow was the loss of heat as the fluid travels from depth to the surface. Further analyses demonstrated the benefit of an alternative heat exchanger configuration characterized by thermally insulated sections of the upward heat exchanger. These simulations predict production fluid temperature gains between 5 - 10 oC, which may be suitable for geothermal heat pump applications.

  20. Rapid self-heating and internal temperature sensing of lithium-ion batteries at low temperatures

    International Nuclear Information System (INIS)

    Zhang, Guangsheng; Ge, Shanhai; Xu, Terrence; Yang, Xiao-Guang; Tian, Hua; Wang, Chao-Yang

    2016-01-01

    Highlights: • Self-heating lithium-ion battery (SHLB) structure provided a practical solution to the poor performance at subzero temperatures. • We report an improved SHLB that heats from −20 °C to 0 °C in 12.5 seconds, or 56% more rapidly, while consuming 24% less energy than previously reported. • The nickel foil heating element embedded inside a SHLB cell plays a dominant role in rapid self-heating. • The embedded nickel foil can simultaneously perform as an internal temperature sensor (ITS). • 2-sheet design self-heats faster than 1-sheet design due to more uniform internal temperature distribution. - Abstract: The recently discovered self-heating lithium-ion battery structure provided a practical solution to the poor performance at subzero temperatures that has hampered battery technology for decades. Here we report an improved self-heating lithium-ion battery (SHLB) that heats from −20 °C to 0 °C in 12.5 seconds, or 56% more rapidly, while consuming 24% less energy than that reported previously. We reveal that a nickel foil heating element embedded inside a SHLB cell plays a dominant role in self-heating and we experimentally demonstrate that a 2-sheet design can achieve dramatically accelerated self-heating due to more uniform internal temperature distribution. We also report, for the first time, that this embedded nickel foil can simultaneously perform as an internal temperature sensor (ITS) due to the perfectly linear relationship between the foil’s electrical resistance and temperature.

  1. Evaluations of different domestic hot water preparing methods with ultra-low-temperature district heating

    DEFF Research Database (Denmark)

    Yang, Xiaochen; Li, Hongwei; Svendsen, Svend

    2016-01-01

    of Legionella in the DHW (domestic hot water) and assure the comfortable temperature, all substations were installed with supplementary heating devices. Detailed measurements were taken in the substations, including the electricity demand of the supplementary heating devices. To compare the energy and economic...

  2. Performance of low-temperature district heating for low-energy houses

    DEFF Research Database (Denmark)

    Brand, Marek; Dalla Rosa, Alessandro; Svendsen, Svend

    2010-01-01

    A Low Energy District Heating (LEDH) network supplying district heating water with temperature 50°C was built in Lærkehaven-Lystrup, Denmark, as a part of the ongoing “Energy Technology Development and Demonstration Programme” [EUDP, 2008] focused on “CO2-reduction in low energy buildings and com...

  3. Decentralized substations for low-temperature district heating with no Legionella risk, and low return temperatures

    DEFF Research Database (Denmark)

    Yang, Xiaochen; Li, Hongwei; Svendsen, Svend

    2016-01-01

    . From the results, realizing LTDH by the decentralized substation unit, 30% of the annual distribution heat loss inside the building can be saved compared to a conventional system with medium-temperature district heating. Replacing the bypass pipe with an in-line supply pipe and a heat pump...... with domestic hot water (DHW) circulation. In this study, a system with decentralized substations was analysed as a solution to this problem. Furthermore, a modification for the decentralized substation system were proposed in order to reduce the average return temperature. Models of conventional system...... with medium-temperature district heating, decentralized substation system with LTDH, and innovative decentralized substation system with LTDH were built based on the information of a case building. The annual distribution heat loss and the operating costs of the three scenarios were calculated and compared...

  4. 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.

  5. Low temperature heat from natural gas. Life cycle analysis for efficient systems

    International Nuclear Information System (INIS)

    Zogg, M.

    2000-01-01

    A life cycle analysis drawn up on behalf of the Swiss Federal Office of Energy shows that the combined cycle power plant + heat pump (GuD-WP) combination produces less greenhouse effect and makes only about half the contribution to summer smog formation as the operation of heat pumps with the power mix habitually used in Western Europe today. In the co-generation unit + heat pump (BHKW-WP) combination, the environmental impact shows the same values as in current West European power generation

  6. Research results from a prototype for power generation from low temperature heat sources in small and medium sized sawmills

    Energy Technology Data Exchange (ETDEWEB)

    Tveit, Tor-Martin; Hoeeg, Arne; Asphjell, Trond-Atle; Horn, Henning

    2010-07-01

    In this paper we present research results from a low temperature power generation unit prototype, SPP 2-67A, installed at the timber company Moelven Eidsvold Vaerk in Norway. The power generation unit is a Stirling cycle reciprocating engine connected to a generator, which is designed to combine the mature technology for high temperature Stirling engines (as seen for instance as air independent propulsion (AIP) units in submarines) and recent academic work on low temperature Stirling engines. The power generation unit is installed in a boiler room at the Moelven Eidsvold Vaerk plant and uses steam at approximately 1.5 bar pressure as a heat source. The steam is generated in the 5.5 MW biomass-fuelled boiler, where bark of Norway spruce (Picea abies) is the main biofuel. The installation has been intended both to use hot water as a heat sink to demonstrate CHP operation, and cold water from the grid to demonstrate maximum power generation from surplus steam. The installation is part of a research project partly financed by the Research Council of Norway, with the goal of testing new technology to improve the use of bioenergy resources and conversion of heat from biofuels to power. (Author)

  7. Companion Study Guide to Short Course on Geothermal Corrosion and Mitigation in Low Temperature Geothermal Heating Systems

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, II, P F

    1985-04-24

    The economic utilization of geothermal resources with temperatures less than 220 degrees Fahrenheit for purposes other than electric power generation (direct utilization) requires creation of systems with long plant life and minimum operation and maintenance costs. Development of such systems requires careful corrosion engineering if the most cost effective material selections and design choices are to be made. This study guide presents guidelines for materials selection for low-temperature geothermal systems (120 - 200 degrees Fahrenheit), as well as guidance in materials design of heat pump systems for very-lowtemperature geothermal resources (less than 120 degrees Fahrenheit). This guideline is divided into five sections and an Appendix.

  8. Performance analysis of a low-temperature waste heat-driven adsorption desalination prototype

    KAUST Repository

    Thu, Kyaw; Yanagi, Hideharu; Saha, Bidyut Baran; Ng, K. C.

    2013-01-01

    This paper discusses the performance analysis of an advanced adsorption desalination (AD) cycle with an internal heat recovery between the condenser and the evaporator. The AD cycle employs the adsorption-desorption principles to convert sea

  9. The impact of air-tightness in the retrofitting practice of low temperature heating

    OpenAIRE

    Wang, Qian; Holmberg, Sture

    2014-01-01

    In Sweden, the energy usage in existing residential buildings amounted to 147 TWh in 2012, equivalent to almost 40 % of the final overall national energy usage. Among all the end users in building service sectors, 60 % of the final energy in Sweden is used for space heating and domestic hot water (DHW) production in 2013. In order to reduce the supply temperature for space heating in existing buildings, combined approaches are favorably adopted: to reduce the net energy demand by air-tightnes...

  10. An innovative ORC power plant layout for heat and power generation from medium- to low-temperature geothermal resources

    International Nuclear Information System (INIS)

    Fiaschi, Daniele; Lifshitz, Adi; Manfrida, Giampaolo; Tempesti, Duccio

    2014-01-01

    Highlights: • Explotation of medium temperature geothermal resource with ORC–CHP is investigated. • A new CHP configuration to provide higher temperature to thermal user is proposed. • Several organic fluids and wide range of heat demand are studied. • The system produces higher power (almost 55%) in comparison to typical layouts. • Optimal working fluids vary with the characteristics of the heat demand. - Abstract: Medium temperature (up to 170 °C), water dominated geothermal resources are the most widespread in the world. The binary geothermal-ORC power plants are the most suitable energy conversion systems for this kind of resource. Specifically, combined heat and power (CHP) systems have the potential to improve the efficiency in exploiting the geothermal resources by cascading the geothermal fluid heat carrier to successively lower temperature users, thus increasing first and second law efficiency of the entire power plant. However, geothermal CHPs usually extract heat from the geofluid either in parallel or in series to the ORC, and usually provide only low temperature heat, which is seldom suitable for industrial use. In this paper, a new CHP configuration, called Cross Parallel CHP, has been proposed and analyzed. It aims to provide higher temperature heat suitable for industrial use, allowing the exploitation of geothermal resources even in areas where district heating is not needed. The proposed CHP allows the reduction of the irreversibilities in the heat exchangers and the loss to the environment related to the re-injection of geofluid, thus producing higher electric power output while satisfying, at the same time, the heat demand of the thermal utility for a wide range of temperatures and mass flow rates (80–140 °C; 3–13 kg/s). Several organic fluids are investigated and the related optimizing working conditions are found by a built in procedure making use of genetic algorithms. The results show that the optimal working fluids and

  11. Ukrainian brown-coal tars recovered at low-temperature carbonization with solid heating medium

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, V I; Govorova, R P; Fadeicheva, A G; Kigel, T B; Chernykh, M K

    1955-01-01

    Three samples of tar were recovered in the laboratory from brown coals carbonized at 375/sup 0/ to 456/sup 0/ +- 25/sup 0/ in a retort with inner heating by solid circulating medium, namely, semicoke (ratio: 4 or 3:1) first heated to 700/sup 0/. One comparative (parallel) experiment was carried out in a retort with inner heating by inert gases entering the retort at 580/sup 0/ to 600/sup 0/ and leaving it at 115/sup 0/ to 120/sup 0/. The tars that were recovered from the retort with the solid heating medium contained a high percentage of coal dust and moisture, which were separated from the tars in supercentrifuges (15,000 rpm). Four samples of cleaned tars were fractionated in a Cu flask with a 2-ball fractional column. The tars from the retort with the solid-heating medium are characterized by increased yield of the petroleum-ether fraction (16.3 or 19.3%) and decreased yield of the paraffin fraction (15.1 to 21.2%) in comparison with those of tar from the retort with gas heating (5.9% of the petroleum ether fraction and 36.5% of paraffin fraction). The yield of paraffin from the paraffin fraction also decreased from 90.6% to 62.6-74.3%. This result shows that in the first case the carbonized products were cracked to a higher degree than those from the retort with gas heating. In raw phenols recovered from fractions of investigated tars, the yield of the phenol-cresol fraction (182/sup 0/ to 204/sup 0/) decreased from 25.9% to 13.0-18.9%.

  12. The Misselhorn Cycle: Batch-Evaporation Process for Efficient Low-Temperature Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Moritz Gleinser

    2016-05-01

    Full Text Available The concept of the Misselhorn cycle is introduced as a power cycle that aims for efficient waste heat recovery of temperature sources below 100 °C. The basic idea shows advantages over a standard Organic Rankine Cycle (ORC in overall efficiency and utilization of the heat source. The main characteristic of this cycle is the use of at least three parallel batch evaporators instead of continuous heat exchangers. The operational phases of the evaporators are shifted so that there is always one vaporizer in discharge mode. A transient MATLAB® model (The MathWorks: Natick, MA, USA is used to simulate the achievable performance of the Misselhorn cycle. The calculations of the thermodynamic states of the system are based on the heat flux, the equations for energy conservation and the equations of state found in the NIST Standard Reference Database 23 (Reference Fluid Thermodynamic and Transport Properties - REFPROP, National Institute of Standards and Technology: Gaithersburg, MD, USA. In the isochoric batch evaporation, the pressure and the corresponding boiling temperature rise over time. With a gradually increasing boiling temperature, no pinch point limitation occurs. Furthermore, the heat source medium is passed through the evaporators in serial order to obtain a quasi-counter flow setup. It could be shown that these features offer the possibility to gain both high thermal efficiencies and an enhanced utilization of the heat source at the same time. A basic model with a fixed estimated heat transfer coefficient promises a possible system exergy efficiency of 44.4%, which is an increase of over 60% compared to a basic ORC with a system exergy efficiency of only 26.8%.

  13. Numerical simulation of the thermal behavior of heat transfer equipment operated at low temperature

    International Nuclear Information System (INIS)

    Pearsica, C.; Zamfirache, M.; Bornea, A.; Gherghinescu, S.

    2003-01-01

    The paper presents a method for calculating the non-steady heat transfer in a shell and tube heat exchanger. The characteristic equations were solved with a Finite Element Method. As the geometry is cylindrical and axial symmetry was assumed, the equations were solved in a two dimensional geometry. The interpolation functions are linear and the Galerkin method was applied. The process occurred without phase change. For the solving of the algebraic equations associated with the differential equations, we used the method of steepest descendent (gradient method). As results, we present the temperature profile for the tube and shell gas. (author)

  14. Low-Temperature Enhanced Geothermal System using Carbon Dioxide as the Heat-Transfer Fluid

    Energy Technology Data Exchange (ETDEWEB)

    Eastman, Alan D. [GreenFire Energy, Emeryville, CA (United States)

    2014-07-24

    This report describes work toward a supercritical CO2-based EGS system at the St. Johns Dome in Eastern Arizona, including a comprehensive literature search on CO2-based geothermal technologies, background seismic study, geological information, and a study of the possible use of metal oxide heat carriers to enhance the heat capacity of sCO2. It also includes cost estimates for the project, and the reasons why the project would probably not be cost effective at the proposed location.

  15. Low-temperature heat capacity and thermodynamic functions of vitamin B{sub 12}

    Energy Technology Data Exchange (ETDEWEB)

    Knyazev, A.V., E-mail: knyazevav@gmail.com; Smirnova, N.N.; Plesovskikh, A.S.; Shushunov, A.N.; Knyazeva, S.S.

    2014-04-01

    Graphical abstract: - Highlights: • Temperature dependence of heat capacity of vitamin B{sub 12} has been measured by precision adiabatic vacuum calorimetry. • The thermodynamic functions of the vitamin B{sub 12} have been determined for the range from T → 0 to 343 K. • The character of heterodynamics of structure was detected. • The thermal stability of cyanocobalamin was studied by differential scanning calorimetry. - Abstract: In the present work temperature dependence of heat capacity of vitamin B{sub 12} (cyanocobalamin) has been measured for the first time in the range from 6 to 343 K by precision adiabatic vacuum calorimetry. Based on the experimental data, the thermodynamic functions of the vitamin B{sub 12}, namely, the heat capacity, enthalpy H°(T) − H°(0), entropy S°(T) − S°(0) and Gibbs function G°(T) − H°(0) have been determined for the range from T → 0 to 343 K. The value of the fractal dimension D in the function of multifractal generalization of Debye's theory of the heat capacity of solids was estimated and the character of heterodynamics of structure was detected. The thermal stability of cyanocobalamin was also studied by differential scanning calorimetry.

  16. Low-temperature heat capacity and thermodynamic functions of vitamin B12

    International Nuclear Information System (INIS)

    Knyazev, A.V.; Smirnova, N.N.; Plesovskikh, A.S.; Shushunov, A.N.; Knyazeva, S.S.

    2014-01-01

    Graphical abstract: - Highlights: • Temperature dependence of heat capacity of vitamin B 12 has been measured by precision adiabatic vacuum calorimetry. • The thermodynamic functions of the vitamin B 12 have been determined for the range from T → 0 to 343 K. • The character of heterodynamics of structure was detected. • The thermal stability of cyanocobalamin was studied by differential scanning calorimetry. - Abstract: In the present work temperature dependence of heat capacity of vitamin B 12 (cyanocobalamin) has been measured for the first time in the range from 6 to 343 K by precision adiabatic vacuum calorimetry. Based on the experimental data, the thermodynamic functions of the vitamin B 12 , namely, the heat capacity, enthalpy H°(T) − H°(0), entropy S°(T) − S°(0) and Gibbs function G°(T) − H°(0) have been determined for the range from T → 0 to 343 K. The value of the fractal dimension D in the function of multifractal generalization of Debye's theory of the heat capacity of solids was estimated and the character of heterodynamics of structure was detected. The thermal stability of cyanocobalamin was also studied by differential scanning calorimetry

  17. Low-temperature specific-heat and thermal-conductivity of silica aerogels

    DEFF Research Database (Denmark)

    Bernasconi, A.; Sleator, T.; Posselt, D.

    1992-01-01

    Specific heat, C(p), and thermal conductivity, lambda, have been measured on a series of base-catalyzed silica aerogels at temperatures between 0.05 and 20 K. Results for both C(p)(T) and lambda(T) confirm that the different length-scale regions observed in the aerogel structure are reflected...

  18. Low-temperature specific heat and thermal conductivity of silica aerogels

    DEFF Research Database (Denmark)

    Sleator, T.; Bernasconi, A.; Posselt, D.

    1991-01-01

    Specific-heat and thermal-conductivity measurements were made on a series of base-catalyzed silica aerogels at temperatures between 0.05 and 20 K. Evidence for a crossover between regimes of characteristically different excitations was observed. The data analysis indicates a "bump" in the density...

  19. Method and installation for the production of heat energy at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Prost, R; Broche, J

    1976-07-08

    The invention concerns a refrigeration source, whose temperature ajusts itself to a pre-set and definite value. The equipment includes two regenerators, whose refrigeration ends are connected to each other by a canal, which has a calibrated reduced section. The refrigeration ends and their connection are inserted into a copper block, which acts as the refrigeration source. The heating end of the lst regenerator is joined to the suction side of a compressor over a switchable valve, while the front side of the compressor is joined to the heating end of the 2nd regenerator over a exchanger and again a switchable valve; when the valve is switched the regenerators are joined to the circuit in an opposite way. The other side of the heat exchanger is, for example, flowed through by tap water for the purpose of cooling. The circuit described is charged with a gas mixture, which consists of hydrocarbon with different boiling points, and, when necessary, consisting of a nitrogen portion. Thus, the gas charge is led from the regenerator, under pressure, into the second one, where condenses by graduation from heat end to refriguration end. The valves are switched back as soon as the initial pressure of the gas has reached a reference value. For this purpose a pressure measuring sensor is provided, which activates a control device, i.e. an electronic control device, which is the main item of this invention.

  20. Low temperature anomaly of light stimulated magnetization and heat capacity of the 1D diluted magnetic semiconductors

    Science.gov (United States)

    Geffe, Chernet Amente

    2018-03-01

    This article reports magnetization and specific heat capacity anomalies in one dimensional diluted magnetic semiconductors observed at very low temperatures. Based on quantum field theory double time temperature dependent Green function technique is employed to evaluate magnon dispersion and the time correlation function. It is understood that magnon-photon coupling and magnetic impurity concentration controls both, such that near absolute temperature magnetization is nearly zero and abruptly increase to saturation level with decreasing magnon-photon coupling strength. We also found out dropping of magnetic specific heat capacity as a result of increase in magnetic impurity concentration x, perhaps because of inter-band disorder that would suppress the enhancement of density of spin waves.

  1. Low temperature anomaly of light stimulated magnetization and heat capacity of the 1D diluted magnetic semiconductors

    Directory of Open Access Journals (Sweden)

    Chernet Amente Geffe

    2018-03-01

    Full Text Available This article reports magnetization and specific heat capacity anomalies in one dimensional diluted magnetic semiconductors observed at very low temperatures. Based on quantum field theory double time temperature dependent Green function technique is employed to evaluate magnon dispersion and the time correlation function. It is understood that magnon-photon coupling and magnetic impurity concentration controls both, such that near absolute temperature magnetization is nearly zero and abruptly increase to saturation level with decreasing magnon-photon coupling strength. We also found out dropping of magnetic specific heat capacity as a result of increase in magnetic impurity concentration x, perhaps because of inter-band disorder that would suppress the enhancement of density of spin waves.

  2. Low-temperature specific heat measurements on the NdCoxFe1-xO3 system

    International Nuclear Information System (INIS)

    Bartolome, F.; Kuz'min, M.D.; Bartolome, J.; Blasco, J.; Garcia, J.

    1995-01-01

    Low-temperature specific heat measurements have been carried out on the NdCo x Fe 1-x O 3 perovskite system (x=0, 0.25, 0.5, 0.9, 1). Magnetic ordering of Nd 3+ ions have been observed in NdCoO 3 (at 1.20 K) and NdFeO 3 (at 1.05 K). The studied dilutions, unlike the pure Fe or Co compounds, do not show a magnetic order of the Nd ions due to the stronger molecular field caused by decompensation of the internal field upon the introduction of the (Co 3+ ) magnetic vacancies in the antiferromagnetically ordered Fe subsystem. The specific heat curve of the system at x=0.9 resembles spin-glass behaviour. ((orig.))

  3. Beating the Heat: Magmatism in the Low-Temperature Thermochronologic Record

    Science.gov (United States)

    Murray, K. E.; Reiners, P. W.; Braun, J.; Karlstrom, L.; Morriss, M. C.

    2017-12-01

    The low-temperature thermochronology community was quick to recognize upper-crustal complexities in the geotherm that reflect landscape evolution, but the complex effects of crustal magmatism on thermochronometers can be difficult to independently document and remain underexplored. Because magmatism is common in many regions central to our understanding of tectonics, this is a significant gap in our ability to robustly interpret rock cooling. Here, we use several different numerical approaches to examine how local and regional crustal magmatism affects cooling age patterns and present examples from the western US that demonstrate the importance—and utility—of considering these effects. We modified the finite-element code Pecube to calculate how thermochronometers document the emplacement of simple hot bodies at different crustal levels. Results demonstrate the potential for mid-crustal plutons, emplaced at 10-15 km depth, to reset cooling ages in the overlying rocks at partial-retention depths at the time of magmatism. Permo-Triassic sandstones from the Colorado Plateau's Canyonlands region have apatite cooling ages that exemplify the resulting ambiguity: Oligocene rock cooling can be attributed to either 1 km of erosion or relaxation of a geothermal gradient transiently doubled by mid-crustal magmatism. Despite these complexities, there are compelling reasons to target rocks with magmatic histories. Shallowly emplaced plutons can usefully reset cooling ages in country rocks with protracted near-surface histories, as we have demonstrated in the Colorado Plateau's Henry Mountains. Cooling age patterns are also useful for quantifying magmatic processes themselves. In an ongoing project, we use the pattern of thermochronometer resetting around individual dikes that fed the Columbia River flood basalts, which are exposed in the Wallowa Mountains, to identify long-lived feeder dikes and model their thermal aureoles to further constrain eruptive dynamics. The pattern

  4. The low-temperature heat capacities of Tb, Lu and Y

    International Nuclear Information System (INIS)

    Wells, P.; Lanchester, P.C.; Jones, D.W.; Jordan, R.G.

    1976-01-01

    The heat capacities of Tb, Lu and Y, refined by solid state electro-transport processing have been measured between 1.5 and 16 K. Below 4 K the results were fitted to the expression C = γT + AT 3 where for Tb the nuclear and magnetic contributions were first calculated and subtracted from the total heat capacity. The resultant values of γ(mJ mol -1 K -2 ) and limiting Debye temperatures thetasub(D) (T → 0) were as follows. Tb: γ = 4.4 +- 0.1, thetasub(D) = 178 +- 2 K; Lu: γ = 6.8 +- 0.1, thetasub(D) 205 +- 3 K; Y: γ = 8.2 +- 0.1, thetasub(D) = 248 +- 3 K. The Debye temperature was found in all instances to decrease by about 10% between 4 and 16 K. (author)

  5. System and method for heating ferrite magnet motors for low temperatures

    Science.gov (United States)

    Reddy, Patel Bhageerath; El-Refaie, Ayman Mohamed Fawzi; Huh, Kum-Kang

    2017-07-04

    A system and method for heating ferrite permanent magnets in an electrical machine is disclosed. The permanent magnet machine includes a stator assembly and a rotor assembly, with a plurality of ferrite permanent magnets disposed within the stator assembly or the rotor assembly to generate a magnetic field that interacts with a stator magnetic field to produce a torque. A controller of the electrical machine is programmed to cause a primary field current to be applied to the stator windings to generate the stator magnetic field, so as to cause the rotor assembly to rotate relative to the stator assembly. The controller is further programmed to cause a secondary current to be applied to the stator windings to selectively generate a secondary magnetic field, the secondary magnetic field inducing eddy currents in at least one of the stator assembly and the rotor assembly to heat the ferrite permanent magnets.

  6. System and method for heating ferrite magnet motors for low temperatures

    Science.gov (United States)

    Reddy, Patel Bhageerath; El-Refaie, Ayman Mohamed Fawzi; Huh, Kum-Kang

    2018-05-08

    A system and method for heating ferrite permanent magnets in an electrical machine is disclosed. The permanent magnet machine includes a stator assembly and a rotor assembly, with a plurality of ferrite permanent magnets disposed within the stator assembly or the rotor assembly to generate a magnetic field that interacts with a stator magnetic field to produce a torque. A controller of the electrical machine is programmed to cause a primary field current to be applied to the stator windings to generate the stator magnetic field, so as to cause the rotor assembly to rotate relative to the stator assembly. The controller is further programmed to cause a secondary current to be applied to the stator windings to selectively generate a secondary magnetic field, the secondary magnetic field inducing eddy currents in at least one of the stator assembly and the rotor assembly to heat the ferrite permanent magnets.

  7. Interpretation of heat capacity anomalies: low temperature antiferromagnetism in YbSnPd2

    Science.gov (United States)

    Giudicelli, P.; Bernhoeft, N.

    2004-07-01

    Since the early experiments on critical opalescence, heat capacity anomalies, which herald continuous transitions of phase, are frequently given microscopic interpretation through an appropriate space-time correlation function. Unfortunately, the global nature of the probe often results in an ill-defined spectral representation of the integrated modes and, as such, help is often sought in the general theoretical consensus of the temporal slowing down and spatial divergence of the critical modes. In this letter it is explicitly shown how a large and continuous anomaly in the heat capacity, which announces the antiferromagnetic phase transition in YbSnPd2 as established by independent neutron diffraction techniques, is not associated with a critical slowing down of spatially correlated modes but, surprisingly, with a stiffening of spatially local excitations. It appears that the results may be of relevance in the study of other strongly correlated electron systems.

  8. The DNA electronic specific heat at low temperature: The role of aperiodicity

    Energy Technology Data Exchange (ETDEWEB)

    Sarmento, R.G. [Departamento de Física, Universidade Federal do Rio Grande do Norte, 59072-970, Natal, RN (Brazil); Mendes, G.A. [Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970, Natal, RN (Brazil); Albuquerque, E.L., E-mail: eudenilson@gmail.com [Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970, Natal, RN (Brazil); Fulco, U.L. [Departamento de Biofísica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970, Natal, RN (Brazil); Vasconcelos, M.S. [Escola de Ciências e Tecnologia, Universidade Federal do Rio Grande do Norte, 59072-970, Natal, RN (Brazil); Ujsághy, O. [Department of Theoretical Physics and Condensed Matter Research Group of the Hungarian Academy of Sciences, Budapest University of Technology and Economics, Budafoki út 8, H-1521 Budapest (Hungary); Freire, V.N. [Departamento de Física, Universidade Federal do Ceará, 60455-760, Fortaleza, CE (Brazil); Caetano, E.W.S. [Instituto Federal de Educação, Ciência e Tecnologia do Ceará, 60040-531, Fortaleza, CE (Brazil)

    2012-07-16

    The electronic specific heat spectra at constant volume (C{sub V}) of a long-range correlated extended ladder model, mimicking a DNA molecule, is theoretically analyzed for a stacked array of a double-stranded structure made up from the nucleotides guanine G, adenine A, cytosine C and thymine T. The role of the aperiodicity on C{sub V} is discussed, considering two different nucleotide arrangements with increasing disorder, namely the Fibonacci and the Rudin–Shapiro quasiperiodic structures. Comparisons are made for different values of the band fillings, considering also a finite segment of natural DNA, as part of the human chromosome Ch22. -- Highlights: ► Quasiperiodic sequence to mimic the DNA nucleotides arrangement. ► Electronic tight-binding Hamiltonian model. ► Electronic density of states. ► Electronic specific heat spectra.

  9. Low temperature specific heat of the spin-density-wave compound (TMTSF)2PF6

    DEFF Research Database (Denmark)

    Odin, J.; Lasjaunias, J.C.; Biljakovic, K.

    1994-01-01

    We report on specific heat measurements of the SDW compound (TMTSF)2PF6 between 2 and 25 K, performed by two different techniques. We discuss the two successive transitions which occur in this T-range : the SDW ordering transition at T = 12.1 K, and a glass transition around-3-3.5 K. The latter i...... is very dependent on the kinetics of measurements, and has all characteristic features of freezing of supercooled liquids....

  10. Low-temperature heat capacity of small Nb3Sn polycrystals by ac calorimetry

    International Nuclear Information System (INIS)

    Viswanathan, R.; Johnston, D.C.

    1976-01-01

    It is shown by an ac calorimetry technique that the multiple heat capacity anomalies which occur below the superconducting transition temperature for small polycrystalline Nb 3 Sn samples are intrinsic to these samples. The recent suggestions that shear stresses can account for these results are analyzed for their validity. The dependence of the occurrence of these multiple anomalies upon the thermal history of the samples was investigated

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

    Science.gov (United States)

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

    2017-12-01

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

  12. Low-temperature heat capacity of Al(C11H19O2)3

    International Nuclear Information System (INIS)

    Bespyatov, Michael A.; Chernyaikin, Ivan S.; Naumov, Viktor N.; Stabnikov, Pavel A.; Gelfond, Nikolay V.

    2014-01-01

    Highlights: • The temperature dependence of heat capacity of Al(C 11 H 19 O 2 ) 3 has been measured. • The experimental data were used to calculate standard thermodynamic functions. • The thermodynamic functions at 298.15 K are presented. - Abstract: The heat capacity of Al(C 11 H 19 O 2 ) 3 was measured by adiabatic-shield calorimetry in the temperature range 6–320 K; no transition or thermal anomalies were found. The thermodynamic functions (entropy, enthalpy, and reduced Gibbs free energy) at 298.15 K have been calculated using the obtained experimental heat capacity data. The obtained standard values are as follows: C° p,m = (882.3 ± 1.3) J mol −1 K −1 , Δ 0 298.15 S° m = J(980 ± 2) mol −1 K −1 , Δ 0 298.15 H° m = (145.1 ± 0.2) kJ mol −1 , Φ° m = (493.4 ± 1.7) J mol −1 K −1

  13. Design of a low temperature district heating network with supply recirculation

    DEFF Research Database (Denmark)

    Li, Hongwei; Dalla Rosa, Alessandro; Svendsen, Svend

    2010-01-01

    The focus on continuing improving building energy efficiency and reducing building energy consumption brings the key impetus for the development of the new generation district heating (DH) system. In the new generation DH network, the supply and return temperature are designed low in order to sig...... calculates the heat loss in the twin pipe as that in the single pipe. The influence of this simplification on the supply/return water temperature prediction was analyzed by solving the coupled differential energy equations.......-pass system starts to function. The aim of this paper is to investigate the influence of by-pass water on the network return temperature and introduce the concept of supply water recirculation into the network design so that the traditional by-pass system can be avoided. Instead of mixing the by-pass water......The focus on continuing improving building energy efficiency and reducing building energy consumption brings the key impetus for the development of the new generation district heating (DH) system. In the new generation DH network, the supply and return temperature are designed low in order...

  14. Treatment of the early-stage glottic cancer using low-temperature radiofrequency coblation

    Directory of Open Access Journals (Sweden)

    Bing Liu

    2016-01-01

    Conclusions: Although the current probe design has limitations for the resection of certain tumors, low-temperature RF coblation appears to be a potentially effective method for the endoscopic resection of selected glottic cancers.

  15. MEMS-Based Boiler Operation from Low Temperature Heat Transfer and Thermal Scavenging

    Directory of Open Access Journals (Sweden)

    Leland Weiss

    2012-04-01

    Full Text Available Increasing world-wide energy use and growing population growth presents a critical need for enhanced energy efficiency and sustainability. One method to address this issue is via waste heat scavenging. In this approach, thermal energy that is normally expelled to the environment is transferred to a secondary device to produce useful power output. This paper investigates a novel MEMS-based boiler designed to operate as part of a small-scale energy scavenging system. For the first time, fabrication and operation of the boiler is presented. Boiler operation is based on capillary action that drives working fluid from surrounding reservoirs across a heated surface. Pressure is generated as working fluid transitions from liquid to vapor in an integrated steamdome. In a full system application, the steam can be made available to other MEMS-based devices to drive final power output. Capillary channels are formed from silicon substrates with 100 µm widths. Varying depths are studied that range from 57 to 170 µm. Operation of the boiler shows increasing flow-rates with increasing capillary channel depths. Maximum fluid mass transfer rates are 12.26 mg/s from 170 µm channels, an increase of 28% over 57 µm channel devices. Maximum pressures achieved during operation are 229 Pa.

  16. Numerical analysis on a four-stage looped thermoacoustic Stirling power generator for low temperature waste heat

    International Nuclear Information System (INIS)

    Wang, Kai; Qiu, Limin

    2017-01-01

    Highlights: • Four-stage looped thermoacoustic power generator for waste heat is studied. • Coupling position is found to have remarkable effects on performance. • Better efficiency is available when coupled near the cold ends of the cores. • The influence of the regenerator position on the efficiency is weak. • Matching between the acoustic impedances of engine and alternator is important. - Abstract: Recent developments in thermoacoustic technologies have demonstrated that multi-stage looped thermoacoustic Stirling engine would be a promising option for harvesting waste heat. Previous studies on multi-stage looped thermoacoustic systems were mainly focused on heat-driven refrigeration or heat pumping, while much fewer work were done on power generations, especially those for recovering low temperature heat. In this work, a four-stage looped thermoacoustic Stirling power generator for generating electricity from low temperature waste heat at 300 °C is systematically studied. A numerical model is built and then validated on an experimental four-stage looped thermoacoustic Stirling engine. On the basis of the validated model, the effects of the coupling position for the linear alternators and the regenerator position on the acoustic characteristics and performances of the power generation system are numerically investigated. The distributions of the acoustic fields along the loop, including the pressure amplitude, volume flow rate, phase angle, specific acoustic impedance and acoustic power, are presented and analysed for three representative coupling modes. Superior efficiency is achieved when the linear alternators are coupled near the cold ends of the thermoacoustic cores on the resonators, while more electric power is generated at the hot ends. The worst performance is expected when the linear alternators are connected at the middle of the resonators. The underling mechanisms are further explained detailedly by analysing the characteristics of the

  17. Anaerobic treatment of domestic sewage in modified septic tanks at low temperature.

    Science.gov (United States)

    Chen, Zhiqiang; Wen, Qinxue; Guan, Huabin; Bakke, Rune; Ren, Nanqi

    2014-01-01

    Three laboratory-scale septic tanks, an anaerobic baffled reactor (ABR)-septic tank (R1), a Yuhuan drawing three-dimensional-carrier-septic tank (R2) and a conventional septic tank (R3), were operated in parallel over half a year under hydraulic retention times (HRTs) of 36, 24 and 12 h, with a sewage temperature of 16 degrees C. The removal efficiencies of total chemical oxygen demand (CODtot) achieved in R1 and R2 increased by 14%, 21% and 12% and 18%, 3% and 16%, respectively, under three different HRTs, as compared to those in R3. The total nitrogen and phosphorus removal efficiencies were negligible. R1 sludges had a higher specific methane production rate as compared to that of R2 and R3 sludges. The results indicated that the two modified septic tanks can improve the performance in terms of COD and total solids removal, both were suitable technologies for domestic sewage (pre) treatment at low temperature in northern China.

  18. The low-temperature water-water reactor for district heating atomic power plant (DHPP)

    International Nuclear Information System (INIS)

    Skvortsov, S.A.; Sokolov, I.N.; Krauze, L.V.; Nikiporetz, Yu.G.; Philimonov, Yu.V.

    1977-01-01

    The district heating atomic power plant in the article is distinguished by the increased reliability and safety of operation that was provided by the use of following main principles: relatively low parameters of the coolant; the intergral arrangement of equipment and accordingly the minimum branching of the reactor circuit; the natural circulation of coolant of the primary circuit in the steady-state, transient and emergency regimes of reactor operation; the considerable reserves of cold water of the primary circuit in the reactor vessel, providing the emergency cooling; the application of two shells each of which is designed for the total working pressure, the second shell is made of prestressed reinforced concrete that eliminates its brittle failure. (M.S.)

  19. Status report on direct heat and low temperature utilization of geothermal energy in New Zealand

    International Nuclear Information System (INIS)

    Lumb, J.T.; Clelland, L.

    1990-01-01

    The Tasman Pulp and Paper Company's mill at Kawerau continues to be the dominant direct user of geothermal energy in New Zealand. Recent plant changes have increased the effectiveness of the company's use of the resource. Other uses are relatively small in scale and include air and water heating for homes, motels and other commercial and industrial premises. Commercial swimming-pool complexes and pools at hotels, motels and private homes are the other major direct users. This paper reports that overall direct use of the resource has shown a slow increase during the last five years except at Rotorua where the enforced closure of bores has led to more than 70% reduction in use

  20. Space heating with ultra-low-temperature district heating - a case study of four single-family houses from the 1980s

    DEFF Research Database (Denmark)

    Østergaard, Dorte Skaarup; Svendsen, Svend

    2017-01-01

    . These benefits can be maximized if district heating temperatures are lowered as much as possible. In this paper we report on a project where 18 Danish single-family houses from the 1980s were supplied by ultra-low temperature district heating with a supply temperature as low as 45 degrees C for the main part...... of the year. The houses were heated by the existing hydraulic radiator systems, while domestic hot water was prepared by use of district heating and electric boosting. This paper evaluated the heating system temperatures that were necessary in order to maintain thermal comfort in four of the houses. First...... the four houses were modelled in the building simulation tool IDA ICE. The simulation models included the actual radiator sizes and the models were used to simulate the expected thermal comfort in the houses and resulting district heating return temperatures. Secondly measurements of the actual district...

  1. Heat capacity and monogamy relations in the mixed-three-spin XXX Heisenberg model at low temperatures

    Science.gov (United States)

    Zad, Hamid Arian; Movahhedian, Hossein

    2016-08-01

    Heat capacity of a mixed-three-spin (1/2,1,1/2) antiferromagnetic XXX Heisenberg chain is precisely investigated by use of the partition function of the system for which, spins (1,1/2) have coupling constant J1 and spins (1/2,1/2) have coupling constant J2. We verify tripartite entanglement for the model by means of the convex roof extended negativity (CREN) and concurrence as functions of temperature T, homogeneous magnetic field B and the coupling constants J1 and J2. As shown in our previous work, [H. A. Zad, Chin. Phys. B 25 (2016) 030303.] the temperature, the magnetic field and the coupling constants dependences of the heat capacity for such spin system have different behaviors for the entangled and separable states, hence, we did some useful comparisons between this quantity and negativities of its organized bipartite (sub)systems at entangled and separable states. Here, we compare the heat capacity of the mixed-three-spin (1/2,1,1/2) system with the CREN and the tripartite concurrence (as measures of the tripartite entanglement) at low temperature. Ground state phase transitions, and also, transition from ground state to some excited states are explained in detail for this system at zero temperature. Finally, we investigate the heat capacity behavior around those critical points in which these quantum phase transitions occur.

  2. Performance study on a low-temperature absorption–compression cascade refrigeration system driven by low-grade heat

    International Nuclear Information System (INIS)

    Xu, Yingjie; Chen, Guangming; Wang, Qin; Han, Xiaohong; Jiang, Ning; Deng, Shiming

    2016-01-01

    Highlights: • An absorption–compression system for low-temperature is developed and analyzed. • Cooling capacity, compression power, and discharge temperature are all improved. • At −170 °C, giving 200 W low-grade cooling capacity, COP increases by 28.6%. • Simulation results are verified experimentally, showing good agreement. - Abstract: This paper presents a performance study on a low-temperature absorption–compression cascade refrigeration system (LACRS), which consists of an absorption subsystem (AS) and a vapor compression auto-cascade subsystem (CS). In the system, low-grade heat of AS is used to subcool the CS, which can obtain cold energy at −170 °C. A simulation study is carried out to investigate the effects of evaporating temperature and low-grade cooling capacity on system performance. The study results show that as low-grade cooling capacity from the AS is provided to the CS, high-grade cooling capacity increases, compressor power consumption decreases, and the COP of the CS therefore increases. Comparing with compression auto-cascade cycle, the largest COP improvement of LACRS is about 38%. The model is verified by experimental data. An additional high-grade cooling capacity is obtained experimentally at −170 °C. The study results presented in this paper not only demonstrate the excellent performance of the LACRS, but also provide important guidance to further system design, and practical application.

  3. Low temperature sensitization behavior in the weld metal of austenitic stainless steel. Study on low temperature sensitization in weldments of austenitic stainless steels and its improvement by laser surface melting treatment. 1

    International Nuclear Information System (INIS)

    Mori, Hiroaki; Nishimoto, Kazutoshi; Nakao, Yoshikuni

    1996-01-01

    Low temperature sensitization (LTS) behavior in the weld metal of Type308 stainless steel was investigated in this study. Three kinds of Type308 stainless steels, of which carbon contents were 0.04%, 0.06% and 0.08%, were used for this study. TIG welding method was adopted to make the weld metals. Weld metals were subjected to the sensitizing heat treatment in the temperature range between 773 K and 1073 K. The degree of sensitization were examined by the EPR method and the Strauss test. Chromium carbide was absorbed to precipitate at δ/γ grain boundaries in the as-welded weld metals Corrosion test results have shown that the higher carbon content in the weld metal is, the earlier sensitization yields in it. Sensitization in weld metals is found to occur faster than in those solution heat-treated at 1273 K prior to sensitizing heat-treatment. This fact suggests that preexisted chromium carbides have an effect to accelerate sensitization. That is, it is apparent that LTS phenomenon occur even in the weld metal. Moreover, sensitization in the weld metal has occurred in much shorter time than in HAZ, which is attributed to the preferential precipitation of chromium carbide at δ/γ grain boundaries in the weld metals. (author)

  4. Low-temperature specific heat of the degenerate supersymmetric t-J model in one dimension

    International Nuclear Information System (INIS)

    Lee, K.; Schlottmann, P.

    1996-01-01

    We consider the one-dimensional SU(N)-invariant t-J model, which consists of electrons with N spin components on a lattice with nearest-neighbor hopping t constrained by the excluded multiple occupancy of the sites and spin-exchange J between neighboring lattice sites. The model is integrable and has been diagonalized in terms of nested Bethe ansatze at the supersymmetric point t=J. The low-T specific heat is proportional to T. The γ-coefficient is extracted from the thermodynamic Bethe-ansatz equations and is expressed in terms of the spin wave velocities and the group velocity of the charges for arbitrary N, band filling, and splitting of the levels (magnetic and crystalline fields). Our results contain the following special cases: (i) For N=2 the traditional spin-1/2 supersymmetric t-J model, (ii) for exactly one electron per site the SU(N)-Heisenberg chain, and (iii) for N=4 the two-band supersymmetric t-J model with crystalline field splitting. copyright 1996 American Institute of Physics

  5. Sensitivity analysis and thermoeconomic comparison of ORCs (organic Rankine cycles) for low temperature waste heat recovery

    International Nuclear Information System (INIS)

    Feng, Yongqiang; Zhang, Yaning; Li, Bingxi; Yang, Jinfu; Shi, Yang

    2015-01-01

    The sensitivity analysis for low temperature ORCs (organic Rankine cycles), as well as the thermoeconomic comparison between the basic ORC and regenerative ORC using Non-dominated sorting genetic algorithm-II (NSGA-II), are conducted in this paper. The derivatives of five system parameters on system performance are used to evaluate the parametric sensitiveness. The exergy efficiency and the APR (heat exchanger area per unit net power output) are selected as the objective functions for multi-objective optimization using R123 under the low temperature heat source of 423 K. The Pareto frontier solution with bi-objective for maximizing exergy efficiency and minimizing APR is obtained and compared with the corresponding single-objective solutions. The results indicate that the prior consideration of improving thermal efficiency and exergy efficiency is to increase the evaporator outlet temperature. A fitting curve can be yielded from the Pareto frontier between the thermodynamic performance and economic factor. The optimum exergy efficiency and APR of the regenerative ORC obtained from the Pareto-optimal solution are 59.93% and 3.07 m 2 /kW, which are 8.10% higher and 15.89% lower than that of the basic ORC, respectively. The Pareto optimization compromises the thermodynamic performance and economic factor, therefore being more suitable for decision making. - Highlights: • The sensitivity analysis of the basic ORC is conducted. • The Pareto-optimal solution is compared with the single-objective solutions. • Evaporator outlet temperature should be preferentially considered. • 8.10% higher exergy efficiency and 15.89% lower APR for the regenerative ORC

  6. Thermal cooling using low-temperature waste heat. A cost-effective way for industrial companies to improve energy efficiency?

    Energy Technology Data Exchange (ETDEWEB)

    Schall, D.; Hirzel, S. [Fraunhofer Institute for Systems and Innovation Research ISI, Breslauer Strasse 48, 76139 Karlsruhe (Germany)

    2012-11-15

    As a typical cross-cutting technology, cooling and refrigeration equipment is used for a variety of industrial applications. While cooling is often provided by electric compression cooling systems, thermal cooling systems powered by low-temperature waste heat could improve energy efficiency and promise a technical saving potential corresponding to 0.5 % of the total electricity demand in the German industry. In this paper, we investigate the current and future cost-effectiveness of thermal cooling systems for industrial companies. Our focus is on single-stage, closed absorption and adsorption cooling systems with cooling powers between 40 and 100 kW, which use low-temperature waste heat at temperature levels between 70C and 85C. We analyse the current and future cost-effectiveness of these alternative cooling systems using annual cooling costs (annuities) and payback times. For a forecast until 2015, we apply the concept of experience curves, identifying learning rates of 14 % (absorption machines) and 17 % (adsorption machines) by an expert survey of the German market. The results indicate that thermal cooling systems are currently only cost-effective under optimistic assumptions (full-time operation, high electricity prices) when compared to electric compression cooling systems. Nevertheless, the cost and efficiency improvements expected for this still young technology mean that thermal cooling systems could be more cost-effective in the future. However, depending on future electricity prices, a high number of operating hours is still crucial to achieve payback times substantially below 4 years which are usually required for energy efficiency measures to be widely adopted in the industry.

  7. Space heating with ultra-low-temperature district heating - A case study of four single-family houses from the 1980s

    DEFF Research Database (Denmark)

    Østergaard, Dorte Skaarup; Svendsen, Svend

    . These benefits can be maximized if district heating temperatures are lowered as much as possible. In this paper we report on a project where 18 Danish single-family houses from the 1980s were supplied by ultra-low-temperature district heating with a supply temperature as low as 45 °C for the main part...... the four houses were modelled in the building simulation tool IDA ICE. The simulation models included the actual radiator sizes and the models were used to simulate the expected thermal comfort in the houses and resulting district heating return temperatures. Secondly measurements of the actual district...... heating return temperatures in the houses were analysed for different times of the year. The study found that existing Danish single-family houses from the 1980s can be heated with supply temperatures as low as 45 °C for the main part of the year. Both simulation models and test measurements showed...

  8. Energy, economy and exergy evaluations of the solutions for supplying domestic hot water from low-temperature district heating in Denmark

    DEFF Research Database (Denmark)

    Yang, Xiaochen; Li, Hongwei; Svendsen, Svend

    2016-01-01

    District heating in Denmark is going through the transition from 3rd generation (80/40 °C) to 4th generation (50-55 °C/25 °C) systems in,preparation for district heating based completely on renewable fuels by 2035. However, concern about Legionella growth and reduced comfort with low......-temperature domestic hot water supply may be discouraging the implementation of low-temperature district heating. Aimed at providing possible solutions, this study modelled various proposals for district heating systems with supply temperatures of 65 °C, 50 °C and 35 °C and for two different building topologies....... Evaluation models were built to investigate the energy, economy and exergy performances of the proposed domestic hot water systems in various configurations. The configurations of the devised domestic hot water substations were optimised to fit well with both low and ultra-low-temperature district heating...

  9. Low-temperature specific heat of the quasi-two-dimensional charge-density wave compound KMo6O17

    Science.gov (United States)

    Wang, Junfeng; Xiong, Rui; Yin, Di; Li, Changzhen; Tang, Zheng; Wang, Ququan; Shi, Jing; Wang, Yue; Wen, Haihu

    2006-05-01

    Low temperature specific heat (Cp) of quasi-two-dimensional charge-density wave (CDW) compound KMo6O17 has been studied by a relaxation method from 2to48K under zero and 12T magnetic fields. The results show that no specific heat anomaly is found at 16K under both zero and 12T magnetic fields, although an anomaly is clearly observed in the resistivity and magnetoresistance measurements. From the data between 2 and 4K , the density of states at Fermi level is estimated as 0.2eV-1permolecule and the Debye temperature is extracted to be 418K . A bump appearing in Cp/T3 is found between 4 and 48K centered around 12.5-15K , indicating that the phason excitations contribute to the total specific heat similarly as in quasi-one-dimensional CDW conductors. Using a modified Debye model, a pinning frequency of 0.73THz for KMo6O17 is estimated from the phason contribution.

  10. Change in heat load profile for typical Danish multi-storey buildings when energy-renovated and supplied with low-temperature district heating

    DEFF Research Database (Denmark)

    Harrestrup, Maria; Svendsen, Svend

    2013-01-01

    ) supply. When end-use-savings are implemented in buildings concurrent with the application of low-temperature district heating (DH) (supply=55°C, return=25°C) the heat demand profiles for the individual buildings will change. The reduction in peak load is important since it is the dimensioning foundation...... for the future DH-systems and in order to avoid oversized RE-based capacity, a long-term perspective needs to be taken. The results show that it is possible to design the DH-plants based on an average value of the 5 days with highest daily average loads without compromising with indoor thermal comfort. Applying...

  11. Influence of atmospheric pressure low-temperature plasma treatment on the shear bond strength between zirconia and resin cement.

    Science.gov (United States)

    Ito, Yuki; Okawa, Takahisa; Fukumoto, Takahiro; Tsurumi, Akiko; Tatsuta, Mitsuhiro; Fujii, Takamasa; Tanaka, Junko; Tanaka, Masahiro

    2016-10-01

    Zirconia exhibits excellent strength and high biocompatibility in technological applications and it is has therefore been investigated for clinical applications and research. Before setting prostheses, a crown prosthesis inner surface is sandblasted with alumina to remove contaminants and form small cavities. This alumina sandblasting causes stress-induced phase transition of zirconia. Atmospheric-pressure low-temperature plasma has been applied in the dental industry, particularly for adhesives, as a surface treatment to activate the surface energy and remove contaminants. The purpose of this study was to examine the influence of atmospheric-pressure low-temperature plasma treatment on the shear bond strength between zirconia and adhesive resin cement. The surface treatment method was classified into three groups: untreated (Cont group), alumina sandblast treatment (Sb group), and atmospheric-pressure low-temperature plasma treatment (Ps group). Adhesive resin cement was applied to stainless steel and bonded to zirconia. Shear adhesion tests were performed after complete hardening of the cement. Multiple comparisons were performed using a one-way analysis of variance and the Bonferroni method. X-ray diffractometry was used to examine the change in zirconia crystal structure. Statistically significant differences were noted between the control and Sb groups and between the control and Ps groups. In contrast, no statistically significant differences were noted for the Ps and Sb bond strength. Atmospheric-pressure low-temperature plasma treatment did not affect the zirconia crystal structure. Atmospheric-pressure low-temperature plasma treatment improves the bonding strength of adhesive resin cement as effectively as alumina sandblasting, and does not alter the zirconia crystal structure. Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  12. Low-temperature tar from bituminous coal and its further treatment

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, C J

    1950-01-01

    High-temperature carbonization of bituminous coal yields only 3 to 4 percent tar, as compared with 8 to 10 percent or even more for low-temperature carbonization. The yield of phenols is 20 to 30 times as great from the low-temperature tar. Five conditions that must be met by a satisfactory low-temperature carbonization process are listed. The only method that satisfies all of these conditions is the Brennstoff-Technik (BT) process, in which iron retorts with movable walls are used. One disadvantage of most of the other processes is the high-pitch content of the tar. These tars are processed further to a neutral oil and a phenol-containing oil which are good diesel fuels with high-cetane numbers; the neutral oil can be fractionated to give oils of high-, medium-, and low-cetane number. Attempts to fractionate the tar oil by solvents have not proved commercially useful. However, the tar can be diluted with low-temperature light oil and phenols extracted with NaOH solution without distillation. Some difficulty is found, owing to the simultaneous extraction of viscous resins and other products that are readily removed from the phenols by distillation.

  13. Case study of low-temperature heating in an existing single-family house-A test of methods for simulation of heating system temperatures

    DEFF Research Database (Denmark)

    Østergaard, Dorte Skaarup; Svendsen, Svend

    2016-01-01

    and the calculated indoor temperatures and radiator return temperatures were compared to temperatures measured in the case house. The results showed that the detail of the simulation model has a large influence on the results obtained. The estimated return temperatures from the radiators varied by up to 16 degrees C...... depending on the assumptions made in the simulation model. The results indicated that a detailed building simulation model can provide a good estimate of the actual heating system operation, provided that actual radiators and realistic indoor temperatures are taken into account in the model. (C) 2016......Low-temperature heating provides an efficient way of heating our buildings. To obtain a high efficiency it is important that the heating systems in the buildings are operated with both low supply and return temperatures. This study set out to investigate how typical assumptions in the modelling...

  14. Molasses wastewater treatment and lipid production at low temperature conditions by a microalgal mutant Scenedesmus sp. Z-4

    OpenAIRE

    Ma, Chao; Wen, Hanquan; Xing, Defeng; Pei, Xuanyuan; Zhu, Jiani; Ren, Nanqi; Liu, Bingfeng

    2017-01-01

    Background Simultaneous wastewater treatment and lipid production by oleaginous microalgae show great potential to alleviate energy shortage and environmental pollution, because they exhibit tremendous advantages over traditional activated sludge. Currently, most research on wastewater treatment by microalgal are carried out at optimized temperature conditions (25?35??C), but no information about simultaneous wastewater treatment and lipid production by microalgae at low temperatures has been...

  15. Specific heat of superconducting metallic glasses at low temperatures; Spezifische Waerme von supraleitenden metallischen Glaesern bei tiefen Temperaturen

    Energy Technology Data Exchange (ETDEWEB)

    Reifenberger, Andreas

    2017-11-15

    In the framework of this thesis we performed, for the first time, an in-depth investigation of the thermodynamic properties of superconducting bulk metallic glasses (BMGs) by means of specific heat measurements in the temperature range between 25 mK and 300 K. To determine the specific heat we used a setup based on the well-established relaxation method. Furthermore we developed a novel micro-fabricated platform to measure superconducting, mg-sized samples down to T=5 mK. The platform temperature is measured by a metallic paramagnetic Ag:Er sensor that is inductively coupled to the input coil of a dc-SQUID by means of a micro-structured gradiometric meander coil. Thereby, we reached a temperature resolution of less than 30 nK/√(Hz) and a very low addenda heat capacity below 200 pJ/K at 50 mK. Connecting the obtained results with thermal conductivity data we were able to consistently model the various degrees of freedom in these BMGs and their interaction mechanisms: For temperatures T>2 K, we find pronounced low temperature anomalies in the phononic specific heat, which are attributed to localized harmonic vibration modes. In the superconducting state close to T{sub C}, where interactions of atomic tunneling systems with quasi-particles need to be taken into account, both measurements agree well with BCS-theory predictions. Far below T{sub C} we find good agreement between the data and the standard tunneling model predictions.

  16. Solar heating and cooling system with absorption chiller and low temperature latent heat storage: Energetic performance and operational experience

    Energy Technology Data Exchange (ETDEWEB)

    Helm, M.; Keil, C.; Hiebler, S.; Mehling, H.; Schweigler, C. [Bavarian Center for Applied Energy Research (ZAE Bayern) (Germany)

    2009-06-15

    Absorption cooling systems based on water/lithium bromide (LiBr) solution typically require an open wet cooling tower to transfer the reject heat to the ambient. Yet, water consumption, the need for water make-up and cleaning, formation of fog, and the risk of Legionella bacteria growth are hindering factors for the implementation of small solar cooling systems. The application of a latent heat storage supporting the heat rejection of the absorption chiller in conjunction with a dry cooling system allows eliminating the wet cooling tower. By that means heat rejection of the chiller is shifted to periods with lower ambient temperatures, i.e. night time or off-peak hours. The system concept and the hydraulic scheme together with an analysis of the energetic performance of the system are presented, followed by a report on the operation of a first pilot installation. (author)

  17. Regional energy-environment system analysis and the role of low-temperature nuclear heat in North China

    International Nuclear Information System (INIS)

    Lu Yingyun

    1984-01-01

    The consumption of commercial energy in China in 1980 amounted to 603 million tonnes of coal equivalent (tce). By the end of this century, according to preliminary forecasting, it will reach some 1200 million tce at least, but there may still be some gaps in the energy supply. Within the structure of China's current energy supply, coal is the dominating fuel, most of which is burned directly, thus causing serious air pollution particularly in urban areas during the winter season. To take into consideration the environmental impacts in formulating appropriate energy policies and carrying out rational energy planning, a practical regional energy system model in connection with environment impacts has been developed. It is essentially a linear programme model. The model has already been used to evaluate the role of alternative energies and technologies including the nuclear option in North China's future urban energy system. The preliminary results thus obtained have shown that nuclear energy, particularly low-temperature nuclear heat, must be introduced to reduce air pollution and fill the gaps in the energy supply. Since small- or medium-sized heat-only reactors have already been reported to be economical, safe and non-polluting, that will be developed in urban areas in North China to a certain extent by the end of this century. (author)

  18. Investigation of electric fields for low-temperature treatment of soils and liquids

    International Nuclear Information System (INIS)

    Heath, W.O.; Goheen, S.C.; Miller, M.C.; Richardson, R.L.

    1992-02-01

    Work was performed to assess the feasibility of an in situ technology for decomposing and removing hazardous organic waste compounds from soils. The technology is based on conductive soil heating and partial electrical discharges (corona) combined with soil-vapor extraction. A pilot-scale facility was developed and used to evaluate the ability to heat and dry soils using polyphase electricity applied through inserted pipes. Uniform heating (100 ± 2 degrees C) and drying to 1.2-wt % moisture were observed. Heating and resultant in situ steam formation have been demonstrated in previous studies to be effective in removing volatile and semivolatile compounds. Corona reactors were constructed to investigate decomposition of organic compounds by oxidants produced in a point-to-liquid corona discharge in ambient air at room temperature and pressure. Point-to-liquid corona was found to be capable of destroying a wide variety of organics, including three aromatics, two polyaromatics, a pcp, a pcb, an alkane, an alkene, an amide, a complexant, a chelator, and an organic dye. Tests with trichloroethylene demonstrated a decontamination factor of 2 x 10 5 (equal to a destruction efficiency of 99.999995%) and nearly complete (99.7%) mineralization, with the main byproduct being aqueous chloride ions. Real-time data on the decolorization kinetics of aqueous methylene blue were obtained using in situ probe colorimetry. Reaction rates were directly proportional to the amount of unreacted dye present and the square of electrode current. Other exploratory tests were performed to investigate concepts for generating ac corona discharges in soil and the ability of those discharges to decompose adsorbed organic compounds. All findings are discussed in relation to a conceptual soil-treatment scenario that includes a description of the basic hardware requirements

  19. Low-temperature heat capacity and standard molar enthalpy of formation of 9-fluorenemethanol (C14H12O)

    International Nuclear Information System (INIS)

    Di, You-Ying; Tan, Zhi-Cheng.; Sun, Xiao-Hong; Wang, Mei-Han; Xu, Fen; Liu, Yuan-Fa; Sun, Li-Xian; Zhang, Hong-Tao

    2004-01-01

    Low-temperature heat capacities of the 9-fluorenemethanol (C 14 H 12 O) have been precisely measured with a small sample automatic adiabatic calorimeter over the temperature range between T=78 K and T=390 K. The solid-liquid phase transition of the compound has been observed to be T fus =(376.567±0.012) K from the heat-capacity measurements. The molar enthalpy and entropy of the melting of the substance were determined to be Δ fus H m =(26.273±0.013) kJ · mol -1 and Δ fus S m =(69.770±0.035) J · K -1 · mol -1 . The experimental values of molar heat capacities in solid and liquid regions have been fitted to two polynomial equations by the least squares method. The constant-volume energy and standard molar enthalpy of combustion of the compound have been determined, Δ c U(C 14 H 12 O, s)=-(7125.56 ± 4.62) kJ · mol -1 and Δ c H m compfn (C 14 H 12 O, s)=-(7131.76 ± 4.62) kJ · mol -1 , by means of a homemade precision oxygen-bomb combustion calorimeter at T=(298.15±0.001) K. The standard molar enthalpy of formation of the compound has been derived, Δ f H m compfn (C 14 H 12 O,s)=-(92.36 ± 0.97) kJ · mol -1 , from the standard molar enthalpy of combustion of the compound in combination with other auxiliary thermodynamic quantities through a Hess thermochemical cycle

  20. Three dimensional optimization of small-scale axial turbine for low temperature heat source driven organic Rankine cycle

    International Nuclear Information System (INIS)

    Al Jubori, Ayad; Al-Dadah, Raya K.; Mahmoud, Saad; Bahr Ennil, A.S.; Rahbar, Kiyarash

    2017-01-01

    Highlights: • Three-dimensional optimization of axial turbine stage is presented. • Six organic fluids suitable for low-temperature heat source are considered. • Three-dimensional optimization has been done for each working fluid. • The results showed highlight the potential of optimization technique. • The performance of optimized turbine has been improved off-design conditions. - Abstract: Advances in optimization techniques can be used to enhance the performance of turbines in various applications. However, limited work has been reported on using such optimization techniques to develop small-scale turbines for organic Rankine cycles. This paper investigates the use of multi-objective genetic algorithm to optimize the stage geometry of a small-axial subsonic turbine. This optimization is integrated with organic Rankine cycle analysis using wide range of high density organic working fluids like R123, R134a, R141b, R152a, R245fa and isobutane suitable for low temperature heat sources <100 °C such as solar energy to achieve the best turbine design and highest organic Rankine cycle efficiency. The isentropic efficiency of the turbine in most of the reported organic Rankine cycle studies was assumed constant, while the current work allows the turbine isentropic efficiency to change (dynamic value) with both operating conditions and working fluids. Three-dimensional computational fluid dynamics analysis and multi-objective genetic algorithm optimization were performed using three-dimensional Reynolds-averaged Navier-Stokes equations with k-omega shear stress transport turbulence model in ANSYS"R"1"7-CFX and design exploration for various working fluids. The optimization was carried out using eight design parameters for the turbine stage geometry optimization including stator and rotor number of blades, rotor leading edge beta angle, trailing edge beta angle, stagger angle, throat width, trailing half wedge angle and shroud tip clearance. Results showed that

  1. Energy, economy and exergy evaluations of the solutions for supplying domestic hot water from low-temperature district heating in Denmark

    International Nuclear Information System (INIS)

    Yang, Xiaochen; Li, Hongwei; Svendsen, Svend

    2016-01-01

    Highlights: • Provided domestic hot water configurations for low-temperature district heating. • Various building typologies and district heating supply temperatures were included. • Different scenarios were evaluated from the energy, economy and exergy aspects. • The benefits of lower return temperature to district heating were investigated. - Abstract: District heating in Denmark is going through the transition from 3rd generation (80/40 °C) to 4th generation (50–55 °C/25 °C) systems in preparation for district heating based completely on renewable fuels by 2035. However, concern about Legionella growth and reduced comfort with low-temperature domestic hot water supply may be discouraging the implementation of low-temperature district heating. Aimed at providing possible solutions, this study modelled various proposals for district heating systems with supply temperatures of 65 °C, 50 °C and 35 °C and for two different building topologies. Evaluation models were built to investigate the energy, economy and exergy performances of the proposed domestic hot water systems in various configurations. The configurations of the devised domestic hot water substations were optimised to fit well with both low and ultra-low-temperature district heating and to reduce the return temperature to district heating. The benefits of lower return temperatures were also analysed compared with the current district heating situation. The evaluation results show that the decentralized substation system with instantaneous heat exchanger unit performed better under the 65 °C and 50 °C district heating scenarios, while the individual micro tank solution consumed less energy and cost less in the 35 °C district heating scenario.

  2. Increase the threshold voltage of high voltage GaN transistors by low temperature atomic hydrogen treatment

    Energy Technology Data Exchange (ETDEWEB)

    Erofeev, E. V., E-mail: erofeev@micran.ru [Tomsk State University of Control Systems and Radioelectronics, Research Institute of Electrical-Communication Systems (Russian Federation); Fedin, I. V.; Kutkov, I. V. [Research and Production Company “Micran” (Russian Federation); Yuryev, Yu. N. [National Research Tomsk Polytechnic University, Institute of Physics and Technology (Russian Federation)

    2017-02-15

    High-electron-mobility transistors (HEMTs) based on AlGaN/GaN epitaxial heterostructures are a promising element base for the fabrication of high voltage electronic devices of the next generation. This is caused by both the high mobility of charge carriers in the transistor channel and the high electric strength of the material, which makes it possible to attain high breakdown voltages. For use in high-power switches, normally off-mode GaN transistors operating under enhancement conditions are required. To fabricate normally off GaN transistors, one most frequently uses a subgate region based on magnesium-doped p-GaN. However, optimization of the p-GaN epitaxial-layer thickness and the doping level makes it possible to attain a threshold voltage of GaN transistors close to V{sub th} = +2 V. In this study, it is shown that the use of low temperature treatment in an atomic hydrogen flow for the p-GaN-based subgate region before the deposition of gate-metallization layers makes it possible to increase the transistor threshold voltage to V{sub th} = +3.5 V. The effects under observation can be caused by the formation of a dipole layer on the p-GaN surface induced by the effect of atomic hydrogen. The heat treatment of hydrogen-treated GaN transistors in a nitrogen environment at a temperature of T = 250°C for 12 h reveals no degradation of the transistor’s electrical parameters, which can be caused by the formation of a thermally stable dipole layer at the metal/p-GaN interface as a result of hydrogenation.

  3. Increase the threshold voltage of high voltage GaN transistors by low temperature atomic hydrogen treatment

    International Nuclear Information System (INIS)

    Erofeev, E. V.; Fedin, I. V.; Kutkov, I. V.; Yuryev, Yu. N.

    2017-01-01

    High-electron-mobility transistors (HEMTs) based on AlGaN/GaN epitaxial heterostructures are a promising element base for the fabrication of high voltage electronic devices of the next generation. This is caused by both the high mobility of charge carriers in the transistor channel and the high electric strength of the material, which makes it possible to attain high breakdown voltages. For use in high-power switches, normally off-mode GaN transistors operating under enhancement conditions are required. To fabricate normally off GaN transistors, one most frequently uses a subgate region based on magnesium-doped p-GaN. However, optimization of the p-GaN epitaxial-layer thickness and the doping level makes it possible to attain a threshold voltage of GaN transistors close to V_t_h = +2 V. In this study, it is shown that the use of low temperature treatment in an atomic hydrogen flow for the p-GaN-based subgate region before the deposition of gate-metallization layers makes it possible to increase the transistor threshold voltage to V_t_h = +3.5 V. The effects under observation can be caused by the formation of a dipole layer on the p-GaN surface induced by the effect of atomic hydrogen. The heat treatment of hydrogen-treated GaN transistors in a nitrogen environment at a temperature of T = 250°C for 12 h reveals no degradation of the transistor’s electrical parameters, which can be caused by the formation of a thermally stable dipole layer at the metal/p-GaN interface as a result of hydrogenation.

  4. Utilisation of bleed steam heat to increase the upper heat source temperature in low-temperature ORC

    Science.gov (United States)

    Mikielewicz, Dariusz; Mikielewicz, Jarosław

    2011-12-01

    In the paper presented is a novel concept to utilize the heat from the turbine bleed to improve the quality of working fluid vapour in the bottoming organic Rankine cycle (ORC). That is a completely novel solution in the literature, which contributes to the increase of ORC efficiency and the overall efficiency of the combined system of the power plant and ORC plant. Calculations have been accomplished for the case when available is a flow rate of low enthalpy hot water at a temperature of 90 °C, which is used for preliminary heating of the working fluid. That hot water is obtained as a result of conversion of exhaust gases in the power plant to the energy of hot water. Then the working fluid is further heated by the bleed steam to reach 120 °C. Such vapour is subsequently directed to the turbine. In the paper 5 possible working fluids were examined, namely R134a, MM, MDM, toluene and ethanol. Only under conditions of 120 °C/40 °C the silicone oil MM showed the best performance, in all other cases the ethanol proved to be best performing fluid of all. Results are compared with the "stand alone" ORC module showing its superiority.

  5. Development and thermochemical characterizations of vermiculite/SrBr_2 composite sorbents for low-temperature heat storage

    International Nuclear Information System (INIS)

    Zhang, Y.N.; Wang, R.Z.; Zhao, Y.J.; Li, T.X.; Riffat, S.B.; Wajid, N.M.

    2016-01-01

    Novel EVM/SrBr_2 composite sorbents with different salt contents were developed for low-temperature thermal energy storage (TES). Simulative sorption experiment was conducted to obtain the sorption kinetics diagram and identify threshold salt content that composite sorbents can hold without solution leakage. Distribution of salt embedded in EVM was observed by extreme-resolution scanning electron microscopy (ER-SEM). Thermochemical characterizations including desorption performance and desorption heat were fully investigated by analyzing simultaneous thermal analyzer (STA) results. Results reveal that sorption process of composite sorbents is divided into three parts: water adsorption of EVM, water adsorption of SrBr_2 crystal and liquid-gas absorption of SrBr_2 solution. Since SrBr_2 solution can be hold in macrospores of EVM, water uptake and energy storage density are greatly increased. It appears that the composite sorbent of EVMSrBr_240 is a promising material for thermal energy storage, with water uptake of 0.53 g/g, mass energy storage density of 0.46 kWh/kg and volume energy storage density of 105.36 kWh/m"3. - Highlights: • Vermiculite/SrBr_2 composite sorbents were developed for thermal energy storage. • Water uptake of composite sorbents is divided into three phases. • Energy storage density of each sorption phase is evaluated via calculations. • EVMSrBr_240 is chosen as optimal sorbent without solution leakage.

  6. Energy, economy and exergy evaluations of the solutions for supplying domestic hot water from low-temperature district heating in Denmark

    DEFF Research Database (Denmark)

    Yang, Xiaochen; Li, Hongwei; Svendsen, Svend

    2016-01-01

    . Evaluation models were built to investigate the energy, economy and exergy performances of the proposed domestic hot water systems in various configurations. The configurations of the devised domestic hot water substations were optimised to fit well with both low and ultra-low-temperature district heating...... °C and 50 °C district heating scenarios, while the individual micro tank solution consumed less energy and cost less in the 35 °C district heating scenario....

  7. The Droplets Condensate Centering in the Vapour Channel of Short Low Temperature Heat Pipes at High Heat Loads

    Science.gov (United States)

    Seryakov, A. V.; Shakshin, S. L.; Alekseev, A. P.

    2017-11-01

    The results of experimental studies of the process of condensate microdroplets centering contained in the moving moist vapour in the vapour channel of short heat pipes (HPs) for large thermal loads are presented. A vapour channel formed by capillary-porous insert in the form of the inner Laval-liked nozzle along the entire length of the HP. In the upper cover forming a condensation surface in the HP, on the diametrical line are installed capacitive sensors, forming three capacitors located at different distances from the longitudinal axis of the vapour channel. With increasing heat load and the boil beginning in the evaporator a large amount of moist vapour in the vapour channel of HP occur the pressure pulsation with frequency of 400-500 Hz and amplitude up to 1·104Pa. These pulsations affect the moving of the inertial droplets subsystem of the vapour and due to the heterogeneity of the velocity profile around the particle flow in the vapour channel at the diameter of microdroplets occurs transverse force, called the Saffman force and shear microdroplets to the center of vapour channel. Using installed in the top cover capacitors we can record the radial displacement of the condensable microdroplets.

  8. Low-temperature anaerobic treatment of hog manure and transformation of biogas into green energy

    Energy Technology Data Exchange (ETDEWEB)

    Van-Anh Truong, L.; Royer, R.

    2004-08-01

    A new environmental solution for hog manure management has been developed by Bio-Terre Systems Inc. in collaboration with Agriculture and Agri-Food Canada. The technical approach combines low-temperature anaerobic digestion, concentration of solids and production of biogas, a renewable energy source. Both small and large agricultural producers can benefit from this approach which helps transform organic matter into value-added by-products. They can fertilize their land with the liquid fraction, supply energy for their buildings with the biogas produced, and export surplus nutrients with the solid fraction. The technology also solves odour problems and destroys pathogenic microorganisms. No pretreatment is needed for this technology which makes use of robust anaerobic microorganisms that are low temperature tolerant. It is a stable process that provides continuous production of biogas with high energy potential. The automated system does not require much monitoring or maintenance. The environmental advantages include the production of biogas rich in methane, which can be used for electrical energy on the farm or sent to the electric power grids; production of high-value, odorless liquid fertilizer; a 50 per cent reduction of the amount of phosphorous in the liquid fraction; and, a 90 per cent reduction in greenhouse gas emissions from hog manure. The profitability of capital investment is assured by both the energy-savings and the agricultural benefits. 1 tab., 1 fig.

  9. The low temperature specific heat and electrical transport, magnetic properties of Pr{sub 0.65}Ca{sub 0.35}MnO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Han, Zhiyong, E-mail: zyhan@cauc.edu.cn

    2017-02-01

    The magnetic properties, electrical transport properties, and low temperature specific heat of polycrystalline perovskite manganese oxide Pr{sub 0.65}Ca{sub 0.35}MnO{sub 3} have been investigated experimentally. It is found that there exists cluster glass state in the sample at low temperature besides the antiferromagnetic insulating state. With the increase of magnetic field, antiferromagnetic insulating state converts to ferromagnetic metal state and the Debye temperature decreases gradually. In addition, the low temperature electron specific heat in zero magnetic field is obviously larger than that of ordinary rare-earth manganites oxide and this phenomenon is related to the itinerant electrons in ferromagnetic cluster state and the disorder in Pr{sub 0.65}Ca{sub 0.35}MnO{sub 3}. - Highlights: • There exists cluster glass state in the sample at low temperature besides the antiferromagnetic insulating state. • With the increase of magnetic field, antiferromagnetic insulating state converts to ferromagnetic metal state. • Low temperature electron specific heat in zero magnetic field is larger than that of ordinary rare-earth manganites oxide.

  10. In-season heat stress compromises postharvest quality and low-temperature sweetening resistance in potato (Solanum tuberosum L.).

    Science.gov (United States)

    Zommick, Daniel H; Knowles, Lisa O; Pavek, Mark J; Knowles, N Richard

    2014-06-01

    The effects of soil temperature during tuber development on physiological processes affecting retention of postharvest quality in low-temperature sweetening (LTS) resistant and susceptible potato cultivars were investigated. 'Premier Russet' (LTS resistant), AO02183-2 (LTS resistant) and 'Ranger Russet' (LTS susceptible) tubers were grown at 16 (ambient), 23 and 29 °C during bulking (111-164 DAP) and maturation (151-180 DAP). Bulking at 29 °C virtually eliminated yield despite vigorous vine growth. Tuber specific gravity decreased as soil temperature increased during bulking, but was not affected by temperature during maturation. Bulking at 23 °C and maturation at 29 °C induced higher reducing sugar levels in the proximal (basal) ends of tubers, resulting in non-uniform fry color at harvest, and abolished the LTS-resistant phenotype of 'Premier Russet' tubers. AO02183-2 tubers were more tolerant of heat for retention of LTS resistance. Higher bulking and maturation temperatures also accelerated LTS and loss of process quality of 'Ranger Russet' tubers, consistent with increased invertase and lower invertase inhibitor activities. During LTS, tuber respiration fell rapidly to a minimum as temperature decreased from 9 to 4 °C, followed by an increase to a maximum as tubers acclimated to 4 °C; respiration then declined over the remaining storage period. The magnitude of this cold-induced acclimation response correlated directly with the extent of buildup in sugars over the 24-day LTS period and thus reflected the effects of in-season heat stress on propensity of tubers to sweeten and lose process quality at 4 °C. While morphologically indistinguishable from control tubers, tubers grown at elevated temperature had different basal metabolic (respiration) rates at harvest and during cold acclimation, reduced dormancy during storage, greater increases in sucrose and reducing sugars and associated loss of process quality during LTS, and reduced ability to improve

  11. Exergy efficiency analysis of ORC (Organic Rankine Cycle) and ORC-based combined cycles driven by low-temperature waste heat

    International Nuclear Information System (INIS)

    Sun, Wenqiang; Yue, Xiaoyu; Wang, Yanhui

    2017-01-01

    Highlights: • ORC-ARC and ORC-ERC driven by low-temperature waste heat are investigated. • Thermodynamic models of basic ORC, ORC-ARC, and ORC-ERC are developed. • Exergy efficiencies of ORC, ORC-ARC, and ORC-ERC are parametrically simulated. • Suitable application conditions of ORC-ARC and ORC-ERC are reported. - Abstract: There is large amount of waste heat resources in industrial processes. However, most low-temperature waste heat is directly discharged into the environment. With the advantages of being energy-efficient, enabling investment-savings and being environmentally friendly, the Organic Rankine Cycle (ORC) plays an important role in recycling energy from low-temperature waste heat. In this study, the ORC system driven by industrial low-temperature waste heat was analyzed and optimized. The impacts of the operational parameters, including evaporation temperature, condensation temperature, and degree of superheat, on the thermodynamic performances of ORC system were conducted, with R113 used as the working fluid. In addition, the ORC-based cycles, combined with the Absorption Refrigeration Cycle (ARC) and the Ejector Refrigeration Cycle (ERC), were investigated to recover waste heat from low-temperature flue gas. The uncoupled ORC-ARC and ORC-ERC systems can generate both power and cooling for external uses. The exergy efficiency of both systems decreases with the increase of the evaporation temperature of the ORC. The net power output, the refrigerating capacity and the resultant exergy efficiency of the uncoupled ORC-ARC are all higher than those of the ORC-ERC for the evaporation temperature of the basic ORC >153 °C, in the investigated application. Finally, suitable application conditions over other temperature ranges are also given.

  12. Numerical modelling and experimental measurements for a low-temperature district heating substation for instantaneous preparation of DHW with respect to service pipes

    International Nuclear Information System (INIS)

    Brand, Marek; Thorsen, Jan Eric; Svendsen, Svend

    2012-01-01

    Traditional district heating (DH) systems are becoming uneconomic as the number of new and renovated buildings with reduced heating requirements increases. To keep DH competitive in the future, heat losses in DH networks need to be reduced. One option is to reduce the supply temperature of DH as much as possible. This requires a review and improvement of a DH network, in-house substations, and the whole domestic hot water (DHW) supply system, with the focus on user comfort, hygiene, overall cost and energy efficiency. This paper describes some practical approaches to the implementation of low-temperature district heating (LTDH) with an entry-to-substation temperature around 50 °C. To this end we developed a numerical model for an instantaneous LTDH substation that takes into consideration the effect of service pipes. The model has been verified and can be used for the further optimization of the whole concept as well for individual components. The results show that the way that the service pipe is operated has a significant effect on waiting time for DHW, heat loss, and overall cost. Furthermore, the service pipe should be kept warm by using a bypass in order to fulfil the comfort requirements for DHW instantaneously prepared. -- Highlights: ► Describes and justifies concept of low-temperature district heating with supply temperature of 50 °C. ► Focuses on DHW preparation in low-temperature district heating in-house substations, considering comfort and Legionella. ► Verified numerical model reports on dynamic performance of an in-house substation, considering operation of service pipes. ► Bypass is needed for instantaneous type of district heating substations to fulfil comfort requirements of users. ► The model developed can be used for future optimization of low-temperature substations and whole district heating networks.

  13. Treatment of solid waste highly contaminated by alpha emitters: Low-temperature impact crushing, leaching and incineration

    International Nuclear Information System (INIS)

    Bertolotti, G.; Vigreux, B.; Caillol, A.; Koehly, G.

    1987-01-01

    Reprocessing plants, hot laboratories and fuel fabrication plants produce solid wastes containing residual amounts of plutonium and uranium in nitrate and oxide form at concentrations up to several tens of grams per m/sup 3/. Dismantling of nuclear facilities having handled these radioelements also generates large volumes of solid wastes highly contaminated with alpha emitters. It is desirable to process these alpha wastes to recover valuable fissile materials and/or permit surface storage. Solid waste treatment by low-temperature impact crushing and then leaching, after minimal sorting and classifying at the sites of production, meets the corresponding requirements for high volume reduction plus fissile material recovery or waste decontamination. Additional volume reduction of crushed wastes containing mainly combustible materials can be obtained by incineration. This is facilitated by the low fissile material content after low-temperature impact crushing and leaching. Sorted wastes can also be leached or incinerated directly after, in most cases, crushing by more conventional techniques

  14. Cold adaptation and replicable microbial community development during long-term low-temperature anaerobic digestion treatment of synthetic sewage.

    Science.gov (United States)

    Keating, C; Hughes, D; Mahony, T; Cysneiros, D; Ijaz, U Z; Smith, C J; O'Flaherty, V

    2018-07-01

    The development and activity of a cold-adapting microbial community was monitored during low-temperature anaerobic digestion (LtAD) treatment of wastewater. Two replicate hybrid anaerobic sludge bed-fixed-film reactors treated a synthetic sewage wastewater at 12°C, at organic loading rates of 0.25-1.0 kg chemical oxygen demand (COD) m-3 d-1, over 889 days. The inoculum was obtained from a full-scale anaerobic digestion reactor, which was operated at 37°C. Both LtAD reactors readily degraded the influent with COD removal efficiencies regularly exceeding 78% for both the total and soluble COD fractions. The biomass from both reactors was sampled temporally and tested for activity against hydrolytic and methanogenic substrates at 12°C and 37°C. Data indicated that significantly enhanced low-temperature hydrolytic and methanogenic activity developed in both systems. For example, the hydrolysis rate constant (k) at 12°C had increased 20-30-fold by comparison to the inoculum by day 500. Substrate affinity also increased for hydrolytic substrates at low temperature. Next generation sequencing demonstrated that a shift in a community structure occurred over the trial, involving a 1-log-fold change in 25 SEQS (OTU-free approach) from the inoculum. Microbial community structure changes and process performance were replicable in the LtAD reactors.

  15. Low-temperature heat capacity and the standard molar enthalpy of formation of compound chromium(III) tri(pyrazine-2-carboxylate)

    International Nuclear Information System (INIS)

    Gao, Shengli; Zhang, Sheng; Chen, Sanping; Yang, Desuo

    2012-01-01

    Highlights: ► Low-temperature heat capacities of chromium(III) tri(pyrazine-2-carboxylate) were measured from 78 to 400 K. ► Thermodynamic functions of the compound at 298.15 K were calculated based on low-temperature heat capacity. ► The standard molar enthalpy of formation of the target was determined to be −1207.86 ± 3.39 kJ mol −1 through a designed thermochemical cycle. - Abstract: Low-temperature heat capacities of the coordination compound, chromium(III) tri(pyrazine-2-carboxylate), formulated as Cr(pyza) 3 (pyza = pyrazine-2-carboxylate), were measured by a precision automated adiabatic calorimeter over the temperature range of 78–400 K. A polynomial equation of heat capacities as a function of the temperature was fitted by the least square method. Based on the fitted polynomial equation, the fitted heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated at the interval of 5 K. In accordance with a reasonable thermochemical cycle designed, the standard molar enthalpy of formation of the title complex was determined to be −1207.86 ± 3.39 kJ mol −1 by an isoperibol solution–reaction calorimeter.

  16. Development of micro-scale axial and radial turbines for low-temperature heat source driven organic Rankine cycle

    International Nuclear Information System (INIS)

    Al Jubori, Ayad; Daabo, Ahmed; Al-Dadah, Raya K.; Mahmoud, Saad; Ennil, Ali Bahr

    2016-01-01

    Highlights: • One and three-dimensional analysis with real gas properties are integrated. • Micro axial and radial-inflow turbines configurations are investigated. • Five organic working fluids are considered. • The maximum total isentropic efficiency of radial-inflow turbine 83.85%. • The maximum ORC thermal efficiency based on radial-inflow turbine is 10.60%. - Abstract: Most studies on the organic Rankine cycle (ORC) focused on parametric studies and selection working fluids to maximize the performance of organic Rankine cycle but without attention for turbine design features which are crucial to achieving them. The rotational speed, expansion ratio, mass flow rate and turbine size have markedly effect on turbine performance. For this purpose organic Rankine cycle modeling, mean-line design and three-dimensional computational fluid dynamics analysis were integrated for both micro axial and radial-inflow turbines with five organic fluids (R141b, R1234yf, R245fa, n-butane and n-pentane) for realistic low-temperature heat source <100 °C like solar and geothermal energy. Three-dimensional simulation is performed using ANSYS"R"1"7-CFX where three-dimensional Reynolds-averaged Navier-Stokes equations are solved with k-omega shear stress transport turbulence model. Both configurations of turbines are designed at wide range of mass flow rate (0.1–0.5) kg/s for each working fluid. The results showed that n-pentane has the highest performance at all design conditions where the maximum total-to-total efficiency and power output of radial-inflow turbine are 83.85% and 8.893 kW respectively. The performance of the axial turbine was 83.48% total-to-total efficiency and 8.507 kW power output. The maximum overall size of axial turbine was 64.685 mm compared with 70.97 mm for radial-inflow turbine. R245fa has the lowest overall size for all cases. The organic Rankine cycle thermal efficiency was about 10.60% with radial-inflow turbine and 10.14% with axial turbine

  17. Treatment of Candida albicans biofilms with low-temperature plasma induced by dielectric barrier discharge and atmospheric pressure plasma jet

    International Nuclear Information System (INIS)

    Koban, Ina; Welk, Alexander; Meisel, Peter; Holtfreter, Birte; Kocher, Thomas; Matthes, Rutger; Huebner, Nils-Olaf; Kramer, Axel; Sietmann, Rabea; Kindel, Eckhard; Weltmann, Klaus-Dieter

    2010-01-01

    Because of some disadvantages of chemical disinfection in dental practice (especially denture cleaning), we investigated the effects of physical methods on Candida albicans biofilms. For this purpose, the antifungal efficacy of three different low-temperature plasma devices (an atmospheric pressure plasma jet and two different dielectric barrier discharges (DBDs)) on Candida albicans biofilms grown on titanium discs in vitro was investigated. As positive treatment controls, we used 0.1% chlorhexidine digluconate (CHX) and 0.6% sodium hypochlorite (NaOCl). The corresponding gas streams without plasma ignition served as negative treatment controls. The efficacy of the plasma treatment was determined evaluating the number of colony-forming units (CFU) recovered from titanium discs. The plasma treatment reduced the CFU significantly compared to chemical disinfectants. While 10 min CHX or NaOCl exposure led to a CFU log 10 reduction factor of 1.5, the log 10 reduction factor of DBD plasma was up to 5. In conclusion, the use of low-temperature plasma is a promising physical alternative to chemical antiseptics for dental practice.

  18. Treatment of Candida albicans biofilms with low-temperature plasma induced by dielectric barrier discharge and atmospheric pressure plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Koban, Ina; Welk, Alexander; Meisel, Peter; Holtfreter, Birte; Kocher, Thomas [Unit of Periodontology, Dental School, University of Greifswald, Rotgerberstr. 8, 17475 Greifswald (Germany); Matthes, Rutger; Huebner, Nils-Olaf; Kramer, Axel [Institute for Hygiene and Environmental Medicine, University of Greifswald, Walther-Rathenau-Str. 49 a, 17487 Greifswald (Germany); Sietmann, Rabea [Institute of Microbiology, University of Greifswald, Friedrich-Ludwig-Jahn-Str. 15, 17487 Greifswald (Germany); Kindel, Eckhard; Weltmann, Klaus-Dieter, E-mail: ina.koban@uni-greifswald.d [Leibniz Institute for Plasma Science and Technology (INP), Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany)

    2010-07-15

    Because of some disadvantages of chemical disinfection in dental practice (especially denture cleaning), we investigated the effects of physical methods on Candida albicans biofilms. For this purpose, the antifungal efficacy of three different low-temperature plasma devices (an atmospheric pressure plasma jet and two different dielectric barrier discharges (DBDs)) on Candida albicans biofilms grown on titanium discs in vitro was investigated. As positive treatment controls, we used 0.1% chlorhexidine digluconate (CHX) and 0.6% sodium hypochlorite (NaOCl). The corresponding gas streams without plasma ignition served as negative treatment controls. The efficacy of the plasma treatment was determined evaluating the number of colony-forming units (CFU) recovered from titanium discs. The plasma treatment reduced the CFU significantly compared to chemical disinfectants. While 10 min CHX or NaOCl exposure led to a CFU log{sub 10} reduction factor of 1.5, the log{sub 10} reduction factor of DBD plasma was up to 5. In conclusion, the use of low-temperature plasma is a promising physical alternative to chemical antiseptics for dental practice.

  19. A novel RE-chrome-boronizing technology assisted by fast multiple rotation rolling treatment at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Xing-dong [School of Materials Science and Engineering, Shandong University, Jinan 250061 (China); School of Materials Science and Engineering, Shandong Jianzhu University, Jinan 250101 (China); Xu, Bin, E-mail: xubin@sdjzu.edu.cn [School of Materials Science and Engineering, Shandong Jianzhu University, Jinan 250101 (China); Cai, Yu-cheng [School of Materials Science and Engineering, Shandong Jianzhu University, Jinan 250101 (China)

    2015-12-01

    Highlights: • A nanostructured layer with grain size of approximately 30 nm was successfully fabricated in the upper-layer of carbon steel. • The penetrating rate was enhanced significantly by the fast multiple rotation rolling (FMRR) treatment at low temperature. • A novel and efficient RE-Chrome-Boronizing technology assisted by fast multiple rotation rolling (FMRR) treatment at low temperature was used to fabricate boride layers on the surface of carbon steel. - Abstract: The boride layer was fabricated on the surface of carbon steel by a novel RE-Chrome-Boronizing technology assisted by fast multiple rotation rolling (FMRR) treatment at low temperature. The microstructure of the boride layer was characterized by using scanning electron microscopy (SEM). The microstructure of the top surface layer of substrate was characterized by transmission electron microscopy (TEM) and high resolution rransmission electron microscopy (HRTEM). Experimental results showed that a nanostructured layer with grain size of approximately 30 nm was obtained; the amorphous phase and high-density dislocations were observed in upper-layer of FMRR samples, which led to the reduction of diffusion activation energy of boron atoms. Boride layers fabricated on the FMRR samples are continuous, dense, uniform, and low in brittleness. The penetrating rate was enhanced significantly when the FMRR samples were Cr-Rare earth-boronized at 650 °C for 6 h. The thickness of the boride layer of FMRR samples on carbon steel was approximately 25 μm when the duration was 60 min, which was approximately 1.5 times higher than the original sample. The boride layer consisted of mainly Fe2B, and adheres well to the metallic substrate.

  20. Low temperature waste heat brought into the greenhouse. Scientific investigations of favourable experience in Austria. Niedertemperatur-Abwaerme ins Gewaechshaus gebracht. Wissenschaftliche Untersuchung positiver Erfahrungen in Oesterreich

    Energy Technology Data Exchange (ETDEWEB)

    Schrottmaier; Nadlinger, M. (Bundesanstalt fuer Landtechnik, Wieselburg (Austria))

    1986-01-01

    In the Indinger garden centre at Brunn, the low temperature ground and rack heating (heating the soil by hoses laid 2-5 cm deep in the ballast bed) is compared with conventional heating. Loss of heat of ground heating downwards was prevented by insulating under the hoses with styropor. At low outside temperatures, vegetation heating in the ground and on the table for decorative plants is not sufficient by itself, a thermal insulation umbrella must be used or the peak demand must be met by the old heating system. The lower the air temperature, compared to the pot temperature, the greater is the energy saving. The air and pot temperature must be controlled independently of one another. For the same energy consumption, the pot temperature was 2 K higher. The success in growing things was excellent. (orig.).

  1. Treatment of toxic and hazardous organic wastes by wet oxidation process with oxygenated water at low temperature

    International Nuclear Information System (INIS)

    Piccinno, T.; Salluzzo, A.; Nardi, L.; Gili, M.; Luce, A.; Troiani, F.; Cornacchia, G.

    1989-11-01

    The wet oxidation process using air or molecular oxygen is a well-known process from long time. It is suitable to oxidize several types of waste refractory to the usual biological, thermal and chemical treatments. The drastic operating conditions (high pressures and temperatures) prevented its industrial development. In the last years a new interest was assigned to the process for the treatment of nuclear wastes (organic resins and exhaust organic wastes); the treatment is carried out at widely reduced operating conditions (atmospheric pressure and boiling temperature) by means of metallic catalysts and hydrogen peroxide. With some limits, the wet oxidation with hydrogen peroxide at low temperature can be applied to conventional waste waters containing toxic organic compounds. In the present report are summarized the activities developed at ENEA Fuel Cycle Department by the task force 'Deox' constituted by laboratory and plant specialists in order to verify the application of the wet oxidation process to the treatment of the toxic wastes. (author)

  2. Water-Mediated Photochemical Treatments for Low-Temperature Passivation of Metal-Oxide Thin-Film Transistors.

    Science.gov (United States)

    Heo, Jae Sang; Jo, Jeong-Wan; Kang, Jingu; Jeong, Chan-Yong; Jeong, Hu Young; Kim, Sung Kyu; Kim, Kwanpyo; Kwon, Hyuck-In; Kim, Jaekyun; Kim, Yong-Hoon; Kim, Myung-Gil; Park, Sung Kyu

    2016-04-27

    The low-temperature electrical passivation of an amorphous oxide semiconductor (AOS) thin-film transistor (TFT) is achieved by a deep ultraviolet (DUV) light irradiation-water treatment-DUV irradiation (DWD) method. The water treatment of the first DUV-annealed amorphous indium-gallium-zinc-oxide (a-IGZO) thin film is likely to induce the preferred adsorption of water molecules at the oxygen vacancies and leads to subsequent hydroxide formation in the bulk a-IGZO films. Although the water treatment initially degraded the electrical performance of the a-IGZO TFTs, the second DUV irradiation on the water-treated devices may enable a more complete metal-oxygen-metal lattice formation while maintaining low oxygen vacancies in the oxide films. Overall, the stable and dense metal-oxygen-metal (M-O-M) network formation could be easily achieved at low temperatures (below 150 °C). The successful passivation of structural imperfections in the a-IGZO TFTs, such as hydroxyl group (OH-) and oxygen vacancies, mainly results in the enhanced electrical performances of the DWD-processed a-IGZO TFTs (on/off current ratio of 8.65 × 10(9), subthreshold slope of 0.16 V/decade, an average mobility of >6.94 cm(2) V(-1) s(-1), and a bias stability of ΔVTH IGZO TFTs.

  3. Anaerobic on-site treatment of black water and dairy parlour wastewater in UASB-septic tanks at low temperatures.

    Science.gov (United States)

    Luostarinen, Sari A; Rintala, Jukka A

    2005-01-01

    Anaerobic on-site treatment of synthetic black water (BW) and dairy parlour wastewater (DPWW) was studied in two-phased upflow anaerobic sludge blanket (UASB)-septic tanks at low temperatures (10-20 degrees C). At all temperatures, total chemical oxygen demand (COD(t)) removal was above 90% with BW and above 80% with DPWW and removal of total suspended solids (TSS) above 90% with both wastewaters. Moreover, dissolved COD (COD(dis)) removal was approx. 70% with both wastewaters indicating good biological activity of the sludges. With BW, a single-phased reactor was found sufficient for good COD removals, while with DPWW, a two-phased process was required. Temperature optimum of reactor sludges was still 35 degrees C after long (398d) operation. Most of the nutrients from BW were removed with TSS, while with DPWW nutrient removal was low. In conclusion, UASB-septic tank was found feasible for (pre)treatment of BW and DPWW at low temperatures.

  4. Acid and low temperature treatments on Salmonella Enteritidis inoculated in pork and its subsequent survival in simulated gastric fluid

    Directory of Open Access Journals (Sweden)

    Simone Quintão Silva

    2016-03-01

    Full Text Available ABSTRACT: The objective of this study was to evaluate the acid resistance of Salmonella enterica serovar Enteritidis (S. Enteritidis in stored pork and in simulated gastric fluid (SGF. A culture of S. Enteritidis was subjected to acid treatment prior to inoculation into pork, stored under refrigeration at frozen temperatures and exposed to SGF. The S. Enteritidis CCS3 and ATCC 13076 strains previously subjected to acid treatment (at pH 4.0-5.0 were inoculated in pork and stored at 4°C and -18°C. Storage at 4ºC did not affect the populations of both S. Enteritidis strains. After 84 days at -18°C, the mean population of both CCS3 and ATCC strains were reduced by 0.8 and 1.5 log cycles, respectively. Prior acid treatment did not enhance the survival of both strains at low temperatures. After acid treatment and low temperature storage, S. Enteritidis ATCC 13076 lost culturability after being exposed to SGF for 10 minutes. In contrast, S. Enteritidis CCS3 was tolerant until three hours of SGF exposure. S. Enteritidis CCS3 submitted to pH 4.0 was more tolerant to SGF exposure than when submitted to pH 4.5, 5.0 and without acid treatment. Therefore, this study indicates that exposure to an acidic and cold environment during processing enhanced the ability of S. Enteritidis to survive in the gastric environment of the human stomach, possibly increasing the risk of a Salmonella infection after consumption of pork.

  5. Surface treatment of a titanium implant using low temperature atmospheric pressure plasmas

    Science.gov (United States)

    Lee, Hyun-Young; Tang, Tianyu; Ok, Jung-Woo; Kim, Dong-Hyun; Lee, Ho-Jun; Lee, Hae June

    2015-09-01

    During the last two decades, atmospheric pressure plasmas(APP) are widely used in diverse fields of biomedical applications, reduction of pollutants, and surface treatment of materials. Applications of APP to titanium surface of dental implants is steadily increasing as it renders surfaces wettability and modifies the oxide layer of titanium that hinders the interaction with cells and proteins. In this study, we have treated the titanium surfaces of screw-shaped implant samples using a plasma jet which is composed of a ceramic coaxial tube of dielectrics, a stainless steel inner electrode, and a coper tube outer electrode. The plasma ignition occurred with Ar gas flow between two coaxial metal electrodes and a sinusoidal bias voltage of 3 kV with a frequency of 20 kHz. Titanium materials used in this study are screw-shaped implants of which diameter and length are 5 mm and 13 mm, respectively. Samples were mounted at a distance of 5 mm below the plasma source, and the plasma treatment time was set to 3 min. The wettability of titanium surface was measured by the moving speed of water on its surface, which is enhanced by plasma treatment. The surface roughness was also measured by atomic force microscopy. The optimal condition for wettability change is discussed.

  6. The effects of low-temperature plasma treatment on the capillary properties of inorganic fibers

    Science.gov (United States)

    Garifullin, A. R.; Abdullin, I. Sh; Skidchenko, E. A.; Krasina, I. V.; Shaekhov, M. F.

    2016-01-01

    Solving the problem of achieving high adhesion between the components in the polymeric composite material (PCM) based on carbon fibers (CF) and basalt fibers (BF) is proposed to use the radio-frequency (RF) plasma under lower pressure by virtue of efficiency, environmental friendliness and rationality of the method. The paper gives the results of studies of the properties of CF and BF after RF capacitive discharge plasma treatment. The plasma modification modes of carbon and basalt fiber were investigated. The efficiency of treatment tool in surface properties modification of carbon and basalt fibers was found, namely capillary properties of CF and BF were researched. The optimal treatment modes were selected. It was found that the method of plasma modification in the radio-frequency capacitive discharge under the lower pressure contributes enhancing the capillary properties of inorganic fibers, in particular carbon and basalt ones. It shows the tendency to increase of the adhesive properties in PCM, and, consequently, the increase of the physical and mechanical properties of the products.

  7. The effects of low-temperature plasma treatment on the capillary properties of inorganic fibers

    International Nuclear Information System (INIS)

    Garifullin, A R; Abdullin, I Sh; Skidchenko, E A; Krasina, I V; Shaekhov, M F

    2016-01-01

    Solving the problem of achieving high adhesion between the components in the polymeric composite material (PCM) based on carbon fibers (CF) and basalt fibers (BF) is proposed to use the radio-frequency (RF) plasma under lower pressure by virtue of efficiency, environmental friendliness and rationality of the method. The paper gives the results of studies of the properties of CF and BF after RF capacitive discharge plasma treatment. The plasma modification modes of carbon and basalt fiber were investigated. The efficiency of treatment tool in surface properties modification of carbon and basalt fibers was found, namely capillary properties of CF and BF were researched. The optimal treatment modes were selected. It was found that the method of plasma modification in the radio-frequency capacitive discharge under the lower pressure contributes enhancing the capillary properties of inorganic fibers, in particular carbon and basalt ones. It shows the tendency to increase of the adhesive properties in PCM, and, consequently, the increase of the physical and mechanical properties of the products. (paper)

  8. Low temperature atmospheric microplasma jet array for uniform treatment of polymer surface for flexible electronics

    Science.gov (United States)

    Wang, Tao; Wang, Xiaolin; Yang, Bin; Chen, Xiang; Yang, Chunsheng; Liu, Jingquan

    2017-07-01

    In this paper, the uniformity of polymer film etching by an atmospheric pressure He/O2 microplasma jet array (μPJA) is first investigated with different applied voltage. Plasma characteristics of μPJA were recorded by optical discharge images. Morphologies and chemical compositions of polymer film etched by μPJA were analyzed by optical microscopy, scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS). By increasing the applied voltage from 8.5 kV to 16.4 kV, the non-uniformity of the luminous intensity of the plasma jets increases. It is interesting that the plasma treated regions are actually composed of an etched region and modification region, with distinct morphologies and chemical compositions. The diameters of the etched parylene-C film show the increase of non-uniformity with higher applied voltage. SEM results show that the non-uniformity of surface morphologies of both the modification regions and etched regions increases with the increase of applied voltage. EDS and XPS results also present the significant effect of higher applied voltage on the non-uniformity of surface chemical compositions of both modification and etched regions. The Coulomb interaction of the streamer heads and the hydrodynamic interaction between the plasma jets and the surrounding air are considered to be responsible for this phenomenon. The results shown in this work can help improve the processing quality of polymer film etched by an atmospheric pressure microplasma jet array and two applications are demonstrated to illustrate the uniform downstream surface treatment.

  9. Treatment of solid waste highly contaminated by alpha emitters low-temperature impact crushing/leaching and incineration

    International Nuclear Information System (INIS)

    Carpentier, S.; Bertolotti, G.

    1986-01-01

    Reprocessing plants, hot laboratories, fuel fabrication plants all produce waste containing residual quantities of plutonium and uranium in oxide form which often reach some tens of grammes per m 3 . Appropriate treatment recovers an appreciable amount of fissile material, which could lead to the waste being declassified and able to be disposed of in near ground-level facilities. After a summary sorting at production level, waste can be sent to a low-temperature impact crushing/leaching unit which considerably reduces volumes to be stored. We call this process cryo-crushing/leaching. For burnable crushed particles, a further volume reduction may be obtained by incineration, an operation which is made easier by the low fissile material residue content. Incineration can, of course also be applied directly to burnable solid waste sorted at source and crushed following more conventional methods [fr

  10. Can there be a T3 ln T kind of behaviour of the low temperature specific heat of liquid 3He without the paramagnons?

    International Nuclear Information System (INIS)

    Tripathy, D.N.; Mishra, S.

    1996-01-01

    It is shown that even without invoking the concepts like paramagnons, the temperature dependence of the interparticle correlations in a system of liquid 3 He can give rise a T 3 ln T kind of behaviour of its low temperature fermionic specific heat. It is found to be coming from the self-energy corrections to the bare single particle energy involving the particle-hole propagator. Looking at the similar kind of behaviour observed by us recently for an electron liquid, one may conclude that the T 3 ln T behaviour is perhaps universal for all fermi systems, although for liquid 3 He the very dependence also follows from the paramagnon effects. It is interesting to see that unlike earlier theories, an extremely good fit is obtained with the experimental data over the entire range of low temperatures. (orig.)

  11. Low temperature distillation

    Energy Technology Data Exchange (ETDEWEB)

    Vandegrift, J N; Postel, C

    1929-04-09

    To recover gas, oil tars, and coked residues by low temperature distillation from bituminous coals, lignites, oil shales, and the like, the raw material is fed from a hopper into a rotary retort which is zonally heated, the temperature being greatest at the discharge end. The material is heated first to a relatively low temperature, thereby removing the moisture and lighter volatiles which are withdrawn through a pipe by the suction of a pump, while the higher boiling point volatiles and fixed gases are withdrawn by suction through an outlet from the higher temperature zone. The vapors withdrawn from the opposite ends of the retort pass through separate vapor lines and condensers, and the suction in each end of the retort, caused by the pumps, is controlled by valves, which also control the location of the neutral point in the retort formed by said suction. Air and inert gas may be introduced into the retort from pipe and stack respectively through a pipe, and steam may be admitted into the high temperature zone through a pipe.

  12. Formation of the low-resistivity compound Cu_3Ge by low-temperature treatment in an atomic hydrogen flux

    International Nuclear Information System (INIS)

    Erofeev, E. V.; Kazimirov, A. I.; Fedin, I. V.; Kagadei, V. A.

    2016-01-01

    The systematic features of the formation of the low-resistivity compound Cu_3Ge by low-temperature treatment of a Cu/Ge two-layer system in an atomic hydrogen flux are studied. The Cu/Ge two-layer system is deposited onto an i-GaAs substrate. Treatment of the Cu/Ge/i-GaAs system, in which the layer thicknesses are, correspondingly, 122 and 78 nm, in atomic hydrogen with a flux density of 10"1"5 at cm"2 s"–"1 for 2.5–10 min at room temperature induces the interdiffusion of Cu and Ge, with the formation of a polycrystalline film containing the stoichiometric Cu_3Ge phase. The film consists of vertically oriented grains 100–150 nm in size and exhibits a minimum resistivity of 4.5 µΩ cm. Variations in the time of treatment of the Cu/Ge/i-GaAs samples in atomic hydrogen affect the Cu and Ge depth distribution, the phase composition of the films, and their resistivity. Experimental observation of the synthesis of the Cu_3Ge compound at room temperature suggests that treatment in atomic hydrogen has a stimulating effect on both the diffusion of Cu and Ge and the chemical reaction of Cu_3Ge-compound formation. These processes can be activated by the energy released upon the recombination of hydrogen atoms adsorbed at the surface of the Cu/Ge/i-GaAs sample.

  13. UCC's Western Gateway Building: a Case Study for the Integration of Low Temperature Heating and High Temperature Cooling Systems

    Directory of Open Access Journals (Sweden)

    Michael F. Keohane

    2012-04-01

    Full Text Available This paper deals with the installation of a 1 MW groundwater heat pump for cool ing and heating, a server room heat recovery system and a novel VAV underfloor mechanical ventilation system, in a large third level university building in Cork, Ireland. After describing the building and the mechanical systems the paper presents energy usage and analysis of results for the first year in operation. Such an installation is of interest to engineers and facil ity managers in order to determine how all the systems complement each other, as well as the resultant energy saving potential compared to conventional systems. Large scale groundwater heat pumps with simultaneous heating and cooling capabilities can provide significant operational cost savings, as described in the paper.

  14. Low-temperature heat capacities and standard molar enthalpy of formation of 4-(2-aminoethyl)-phenol(C8H11NO)

    Institute of Scientific and Technical Information of China (English)

    Di You-Ying; Kong Yu-Xia; Yang Wei-Wei; Tan Zhi-Cheng

    2008-01-01

    This paper reports that low-temperature heat capacities of 4-(2-aminoethyl)-phenol(C8H11NO)are measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 400 K.A polynomial equation of heat capacities as a function of the temperature was fitted by the least square method.Based on the fitted polynomial,the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at the interval of 5 K.The energy equivalent,gcalor,of the oxygen-bomb The constant-volume energy of combustion of the compound at T=298.15 K was measured by a precision oxygen-bomb combustion and other thermodynamic principles.Finally,the standard molar enthalpy of formation of the compound

  15. Specific heat characteristics of Ce70Ga8.5Cu18.5Ni3 metallic glass at low temperatures

    Science.gov (United States)

    Liu, Rentao; Zhong, Langxiang; Zhang, Bo

    2018-03-01

    Specific heat behaviors have been studied in Ce70Ga8.5Cu18.5Ni3 bulk metallic glass (BMG) from 2 K to 50 K. The low-temperature specific heat of the Ce-based metallic glass is a combined action of the Fermi liquids term, Debye oscillator term, and Einstein oscillator term as well as excess term. We also observed an intense boson peak around 15 K and attributed it to a harmonic localized Einstein mode influenced by the dense-packed atomic cluster structure. It is also demonstrated that Ce70Ga8.5Cu18.5Ni3 BMG belongs to the strongly correlated heavy-fermion system with a great electron specific heat coefficient and a high Wilson ratio. It exhibits a typical Fermi-Liquid feature when the temperature is above 10 K, while it exhibits a Non-Fermi-Liquid feature when the temperature is below 3.5 K.

  16. Thermo-economic optimization of secondary distribution network of low temperature district heating network under local conditions of South Korea

    DEFF Research Database (Denmark)

    Park, Byung Sik; Imran, Muhammad; Hoon, Im-Yong

    2017-01-01

    . The corresponding heat loss from secondary network, pumping power and area of domestic hot water heat exchanger unit for each supply temperature and temperature difference for required heating load of the apartment complex are calculated. Results indicate that when supply temperature is decreased from 65 °C to 45...... apartment. The Apartment complex has 15 floors, 4 apartments on each floor and each apartment has heating surface area of 85 m2. The supply temperature of the hot water is reduced from 65 °C to 45 °C and the temperature difference between supply and return line is varied from 18 °C to 27 °C...... °C, area of heat exchanger is increased by 68.2%, pumping power is also increased by 9.8% and heat loss is reduced by 15.6%. These results correspond to a temperature difference of 20 °C, the standard temperature difference in South Korea residential heating system. Economic assessment...

  17. Low temperature destructive distillation

    Energy Technology Data Exchange (ETDEWEB)

    1938-07-05

    A process is given and apparatus is described for the destructive distillation at low temperature of coal, oil shale, and the like by subjection to the action of a stream of hot gases or superhearted steam, flowing in a closed circuit. Subsequent treatment of the distillation residues with a gas stream containing oxygen results in combustion of the carbon-containing material therein brings to a high temperature the solid residue, in which the process comprises subsequently contacting the hot solid residue with the fluid stream effecting the distillation.

  18. Simulation and optimization study on a solar space heating system combined with a low temperature ASHP for single family rural residential houses in Beijing

    DEFF Research Database (Denmark)

    Deng, Jie; Tian, Zhiyong; Fan, Jianhua

    2016-01-01

    A pilot project of the solar water heating system combined with a low temperature air source heat pump (ASHP) unit was established in 2014 in a detached residential house in the rural region of Beijing, in order to investigate the system application prospect for single family houses via system...... optimization design and economic analysis. The established system was comprised of the glass heat-pipe based evacuated tube solar collectors with a gross area of 18.8 m2 and an ASHP with a stated heating power of 8 kW for the space heating of a single family rural house of 81.4 m2. The dynamic thermal...... with good building insulation were undertaken to figure out the system economical efficiency in the rural regions of Beijing. The results show that the payback periods of the solar space heating system combined with the ASHP with the collector areas 15.04-22.56 m2 are 17.3-22.4 years for the established...

  19. Simulation of coal low-temperature oxidation heating process in gob with “U+L” ventilation

    Directory of Open Access Journals (Sweden)

    Zhou Pei Ling

    2016-01-01

    Full Text Available In a gob with U + L ventilation, a tail roadway exists, which has important effects on the oxidation heating process and gas concentration in gob areas. Research on the heating process and gas concentration in the “U+L” ventilation can provide the basis for the prevention of spontaneous combustion, thus, the regularities of the oxidation heating process and gas concentration in gob areas were researched by simulation. Results showed that compared with U ventilation, U + L ventilation caused the high temperature zone and high temperature points in the gob areas to increase in depth and width and to be influenced by the distance between the crossheading of the tail roadway and workface. The heating rate of the high-temperature point in the gob with tail roadway was 1.5 times of that in gob without tail roadway, but was unaffected by the location of the tail roadway. Tail roadway had diversion effects on the airflow, especially near return side and the maximum reduction of gas concentration can be 0.36%.

  20. Electron cyclotron heating and current drive approach for low-temperature startup plasmas using O-X-EBW mode conversion

    International Nuclear Information System (INIS)

    Batchelor, D.B.; Bigelow, T.S.

    1997-01-01

    A mechanism for heating and driving currents in very overdense plasmas is considered based on a double-mode conversion: Ordinary mode to Extraordinary mode to electron Bernstein wave. The possibility of using this mechanism for plasma buildup and current ramp in the National Spherical Torus Experiment is investigated

  1. Low temperature measurements of the heat capacity and thermodynamic functions of pseudo-malachite Cu5(PO4)2(OH)4

    International Nuclear Information System (INIS)

    Bissengaliyeva, M.R.; Gogol, D.B.; Bekturganov, N.S.

    2012-01-01

    The investigation of the heat capacity of a natural specimen of copper phosphate—pseudo-malachite Cu 5 (PO 4 ) 2 (OH) 4 in the temperature range between 4.2 K and 320 K has been carried out by the method of low-temperature adiabatic calorimetry. Tabulated values of the heat capacity and thermodynamic functions of the mineral including the changes of entropy and enthalpy and the Gibbs function of free energy have been calculated. The standard values of thermodynamic functions of pseudo-malachite at T = 298.15 K are C p,m ° =(385.43±0.41)J mole −1  K −1 , Δ 0 T S m ° =(412.16±0.61)J mole −1  K −1 , Δ 0 T H m ° =(63681.5±57.0)J mole −1 , F m ° =(198.57±0.47)J mole −1  K −1 . In the low-temperature area 0 tr = (5.772 ± 0.081) J mole −1 K −1 , ΔH tr = (29.94 ± 0.42) J mole −1 .

  2. Structural mechanisms of high-temperature shape changes in titanium-nickel alloys after low-temperature thermomechanical treatment

    International Nuclear Information System (INIS)

    Prokoshkin, S.D.; Turenne, S.; Khmelevskaya, I.Yu.; Brailovski, V.; Trochu, F.

    2000-01-01

    High-Temperature Shape Memory Effect (HTSME) in Ti-Ni alloys and corresponding structural and internal stress changes were studied using dilatometry, in situ electron microscope and X-ray diffractometry. The HTSME induced by the Low Temperature Thermomechanical Treatment (LTMT) consists of two stages. The temperature range of the first stage is limited to 250 o C, while the second stage extends to 400-500 o C. The first stage is caused by the oriented reverse martensite transformation. The heterogeneous residual stress field causes a different thermal stability for the different martensite orientations. During the reverse transformation an anisotropic shift of martensite and austenite X-ray lines is observed that can be due to a relaxation of the orientated stresses and to changes in the martensite lattice. The second stage of HTSME is caused by internal stress relaxation during recovery and polygonization of austenite that are not typical shape memory mechanisms. The possible reasons for the martensite stabilization induced by LTMT will be discussed. (author)

  3. Do salt and low temperature impair metal treatment in stormwater bioretention cells with or without a submerged zone?

    Science.gov (United States)

    Søberg, Laila C; Viklander, Maria; Blecken, Godecke-Tobias

    2017-02-01

    Although seasonal temperature changes and (road) salt in winter and/or coastal stormwater runoff might interfere with the metal treatment performance of stormwater bioretention cells, no previous study has evaluated the effect of these factors and their interactions under controlled conditions. In this 18week long study 24 well established pilot-scale bioretention columns were employed to evaluate the individual and combined effect(s) of low/high temperature, salt and presence of a submerged zone with an embedded carbon source on metal removal using a three factor, two-level full factorial experimental design. In most instances, the three factors significantly influenced the metal outflow concentrations and thus the treatment performance; the effect of temperature depended on the metal in question, salt had an overall negative effect and the submerged zone with carbon source had an overall positive effect. Despite these statistically significant effects, the discharge water quality was generally markedly improved. However, leaching of dissolved Cu and Pb did occur, mainly from bioretention cells dosed with salt-containing stormwater. The highest concentrations of metals were captured in the top layer of the filter material and were not significantly affected by the three factors studied. Overall, the results confirmed that bioretention provides a functioning stormwater treatment option in areas experiencing winter conditions (road salt, low temperatures) or coastal regions (salt-laden stormwater). However, validation of these results in the field is recommended, especially focusing on dissolved metal removal, which may be critically affected under certain conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Supply of domestic hot Water at comfortable temperatures by low-temperature district heating without risk of Legionella

    DEFF Research Database (Denmark)

    Yang, Xiaochen

    disinfection efficacy for Legionella if supplied by LTDH, and inject no additives into the water. Thus, they can be considered as feasible sterilization solutions. In terms of the DHW system design methods, in addition to ensure the safe and hygiene DHW supply, the potential DHW systems should also...... temperature for space heating but lower than LTDH. Therefore, to meet the comfort and hygiene requirements for DHW supply, supplementary heating methods should be combined. However, one obstacle to realize the LTDH/ULTDH is the concern of the violation of the comfort and hygiene requirements of DHW supply....... According to the Danish standard, the supply for DHW should be able to reach 45 °C for the kitchen use and 40 °C for other uses for comfort. Regarding to the hygiene requirements, large DHW system with DHW storage tank and circulation has to use high temperature regime to get rid of Legionella. The storage...

  5. Low-temperature heat-capacity study of the U6X (XequivalentMn, Fe, Co, Ni) compounds

    International Nuclear Information System (INIS)

    Yang, K.N.; Maple, M.B.; DeLong, L.E.; Huber, J.G.; Junod, A.

    1989-01-01

    Measurements of the superconducting- and normal-state heat capacity of U 6 X (XequivalentMn, Fe, Co, Ni) compounds have been performed over a temperature range 1 Kapprox. 6 X compounds have strong renormalizations of the free-carrier effective mass m/sup */ in the range 10m/sub e/approx. 6 X heat capacities suggest the presence of high densities of low-energy excitations of undetermined nature. The results are analyzed in terms of models appropriate to heavy-fermion liquids, and anisotropic or strong-coupled superconductors. The U 6 X compounds form a link between relatively low-m/sup */, high-transition-temperature A15 compounds and the more extreme examples of heavy-fermion superconductors such as UBe/sub 13/, UPt 3 , and CeCuSi 2 for which m/sup */∼10 2 m/sub e/. .AE

  6. Low-temperature specific heat of the 'nearly ferromagnetic' amorphous alloy Ysub(0.22)Nisub(0.78)

    International Nuclear Information System (INIS)

    Garoche, P.; Veyssie, J.J.; Lienard, A.; Rebouillat, J.P.

    1979-01-01

    Results of specific heat measurements, between 0.3K and 10 K in magnetic fields up to 75 kOe, on the 'nearly ferromagnetic' amorphous alloy Ysub(0.22)Nisub(0.78) are reported. The results, especially the magnetic field dependence, exclude any appreciable contribution from uniform paramagnons. In contrast a quantitative analysis is obtained in terms of superparamagnetic clusters, demonstrating that the onset of ferromagnetism, as a function of concentration, is inhomogeneous in this amorphous metallic system. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Willa, K. [Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA; Diao, Z. [Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden; Laboratory of Mathematics, Physics and Electrical Engineering, Halmstad University, P.O. Box 823, SE-301 18 Halmstad, Sweden; Campanini, D. [Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden; Welp, U. [Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA; Divan, R. [Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA; Hudl, M. [Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden; Islam, Z. [X-ray Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA; Kwok, W. -K. [Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA; Rydh, A. [Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden

    2017-12-01

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

  8. Low-temperature heat capacities and standard molar enthalpy of formation of N-methylnorephedrine C211H17NO(s)

    Institute of Scientific and Technical Information of China (English)

    Di You-Ying; Wang Da-Qi; Shi Quan; Tan Zhi-Cheng

    2008-01-01

    This paper reports that low-temperature heat capacities of N-methylnorephedrine C11H17NO(s) have been mea- sured by a precision automated adiabatic calorimeter over the temperature range from T=78 K to T=400 K. A solid to liquid phase transition of the compound was found in the heat capacity curve in the temperature range of T=342- 364 K. The peak temperature, molar enthalpy and entropy of fusion of the substance were determined. The experimental values of the molar heat capacities in the temperature regions of T=78-342 K and T=364-400 K were fitted to two poly- nomial equations of heat capacities with the reduced temperatures by least squares method. The smoothed molar heat capacities and thermodynamic functions of N-methylnorephedrine C11H17NO(s) relative to the standard refer- ence temperature 298.15 K were calculated based on the fitted polynomials and tabulated with an interval of 5 K. The constant-volume energy of combustion of the compound at T=298.15 K was measured by means of an isoperibol preci- sion oxygen-bomb combustion calorimeter. The standard molar enthalpy of combustion of the sample was calculated. The standard molar enthalpy of formation of the compound was determined from the combustion enthalpy and other auxiliary thermodynamic data through a Hess thermochemical cycle.

  9. Design and component testing of a low-temperature waste heat driven refrigeration system. Phases I and II. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Hynek, S.; Borhanian, H.; Krepchin, I.; Walker, D.; Mariano, C.; Fuller, H.; Lee, K.

    1982-03-01

    The design and the component testing of a 20-ton refrigeration system powered by 140/sup 0/F waste heat have been completed. A major advantage of such a system is that essentially all operating power comes from the waste heat with only minor injections of auxiliary power. This Rankine-Rankine system uses R-22 for both power and refrigeration cycles. A single semi-hermetic housing contains the expander, compressor, feed pump, and motor/generator. The integral induction motor/generator acts as a starter, makes up shaft power deficits, absorbs shaft power surpluses, and provides overspeed protection. Experiments determined that 0.0015 in. is the optimum axial clearance for the gerotor R-22 evaporator feed pump to minimize both friction and backleakage, that oil injection to the pump had no effect on either friction or backleage, and that a centrifugal inducer was needed to prevent cavitation under certain operating conditions. Two cylinders of a standard four-cylinder York refrigeration compressor were transformed into expanders to power the remaining two compressor cylinders. Rotary expander valves were used in lieu of conventional poppet valves to lower breathing losses. Testing demonstrated a 75% mechanical efficiency, an 83% isentropic efficiency, and the necessity to support both the rotary valve and the expander wristpins with rolling contact bearings. Fabrication of the 20-ton experimental system is nearing completion and experimental tests are being planned.

  10. A Study on the Low Temperature Brittleness by Cyclic Cooling-Heating of Low Carbon Hot Rolled Steel Plate

    International Nuclear Information System (INIS)

    Lee, Hyo Bok

    1979-01-01

    The ductile-brittle transition phenomenon of low carbon steel has been investigated using the standard Charpy V-notch specimen. Dry ice and acetone were used as refrigerants. Notched specimens were cut from the hot rolled plate produced at POSCO for the Olsen impact test. The effect of cyclic cooling and heating of 0.14% carbon steel on the embrittlement was extensively examined. The ductile-brittle transition temperature was found to be approximately-30 .deg. C. The transition temperature was gradually increased as the number of cooling-heating cycles increased. On a typical V-notch fracture surface it was found that the ductile fracture surface showed a thick and fibrous structure, while the brittle fracture surface a small and light grain with irregular disposition. As expected, the transition temperature was also increased as the carbon content of steel increased. Compared with the case of 0.14% carbon steel, the transition temperature of 0.17% carbon steel was found to be increased about 12 .deg. C

  11. Theoretical analysis of a transcritical power cycle for power generation from waste energy at low temperature heat source

    International Nuclear Information System (INIS)

    Vélez, Fredy; Chejne, Farid; Antolin, Gregorio; Quijano, Ana

    2012-01-01

    The present paper reports the results obtained on a carbon dioxide transcritical power cycle using an energy and exergy analysis. The procedure consisted of modifying the inlet pressure to the turbine from 66 bar, by means of the software HYSYS®, maintaining constant each evaluated turbine inlet temperature (60, 90, 120 and 150 °C) until the net work was approximately zero. As a result, an increase up to 25% for the exergy efficiency, and up to 300% for the energy efficiency are obtained when the inlet temperature to the turbine is risen from 60 to 150 °C. Consequently, the analysis shows the viability of implementing this process as alternative energy, because of the possibility to recovery energy from waste heat from industrial processes.

  12. Experimental investigation on a small pumpless ORC (organic rankine cycle) system driven by the low temperature heat source

    International Nuclear Information System (INIS)

    Gao, P.; Wang, L.W.; Wang, R.Z.; Jiang, L.; Zhou, Z.S.

    2015-01-01

    A small pumpless ORC (organic rankine cycle) system with different scroll expanders modified from compressors of the automobile air-conditioner is established, and the refrigerant R245fa is chosen as the working fluid. Different hot water temperatures of 80, 85, 90 and 95 °C are employed to drive the pumpless ORC system. Experimental results show that a maximum shaft power of 361.0 W is obtained under the hot water temperature of 95 °C, whereas the average shaft power is 155.8 W. The maximum energy efficiency of 2.3% and the maximum exergy efficiency of 12.8% are obtained at the hot water temperature of 90 °C. Meanwhile a test rig for investigating the mechanical loss of the scroll expander is established. The torque caused by the internal mechanical friction of the expander is about 0.4 N m. Additionally, another scroll expander with a displacement of 86 ml/r is also employed to investigate how scroll expander displacement influences the performance of the pumpless ORC system. Finally, the performance of the pumpless ORC system is compared with that of the conventional ORC system, and experimental results show that the small pumpless ORC system has more advantages for the low-grade heat recovery. - Highlights: • A small pumpless ORC (organic rankine cycle) system is established, and different scroll expanders are tested. • The maximum energy and exergy efficiency are 2.3% and 12.8% respectively. • A maximum shaft power of 361.0 W is obtained under the heat source temperature of 95 °C. • The small pumpless ORC system has characteristics of the high efficiency.

  13. The experimental investigation on the performance of a low temperature waste heat-driven multi-bed desiccant dehumidifier (MBDD) and minimization of entropy generation

    KAUST Repository

    Myat, Aung; Thu, Kyaw; Ng, K. C.

    2012-01-01

    We present the experimental investigation on the performance of multi-bed desiccant dehumidification system (MBDD) using a thermodynamic framework with an entropy generation analysis. The cyclic steady state performance of adsorption-desorption processes at the assorted heat source temperatures, and typical ambient humidity conditions was carried out. MBDD unit uses type-RD silica gel pore surface area with of 720 m 2/g. It has a nominal diameter range of 0.4 to 0. 7 mm. The key advantages of MBDD are: (i) it has no moving parts rendering less maintenance, (ii) energy-efficient means of dehumidification by adsorption process with low temperature heat source as compared to the conventional methods, (iii) although it is a pecked bed desiccant, a laminar chamber is employed by arranging the V-shaped configuration of heat exchangers and (iv) it is environmental friendly with the low-carbon footprint. Entropy generation analysis was performed at the assorted heat source temperatures to investigate the performance of MBDD. By conducting the entropy minimization, it is now able to locate the optimal operating conditions of the system while the specific entropy generation is found to be minimal. This analysis shows that the minimization of entropy generation in the dehumidification cycle leads to the maximization of COP in the MBDD and thus, higher delivery of useful effects at the same input resources. © 2011 Elsevier Ltd. All rights reserved.

  14. The experimental investigation on the performance of a low temperature waste heat-driven multi-bed desiccant dehumidifier (MBDD) and minimization of entropy generation

    KAUST Repository

    Myat, Aung

    2012-06-01

    We present the experimental investigation on the performance of multi-bed desiccant dehumidification system (MBDD) using a thermodynamic framework with an entropy generation analysis. The cyclic steady state performance of adsorption-desorption processes at the assorted heat source temperatures, and typical ambient humidity conditions was carried out. MBDD unit uses type-RD silica gel pore surface area with of 720 m 2/g. It has a nominal diameter range of 0.4 to 0. 7 mm. The key advantages of MBDD are: (i) it has no moving parts rendering less maintenance, (ii) energy-efficient means of dehumidification by adsorption process with low temperature heat source as compared to the conventional methods, (iii) although it is a pecked bed desiccant, a laminar chamber is employed by arranging the V-shaped configuration of heat exchangers and (iv) it is environmental friendly with the low-carbon footprint. Entropy generation analysis was performed at the assorted heat source temperatures to investigate the performance of MBDD. By conducting the entropy minimization, it is now able to locate the optimal operating conditions of the system while the specific entropy generation is found to be minimal. This analysis shows that the minimization of entropy generation in the dehumidification cycle leads to the maximization of COP in the MBDD and thus, higher delivery of useful effects at the same input resources. © 2011 Elsevier Ltd. All rights reserved.

  15. Heat treatment furnace

    Science.gov (United States)

    Seals, Roland D; Parrott, Jeffrey G; DeMint, Paul D; Finney, Kevin R; Blue, Charles T

    2014-10-21

    A furnace heats through both infrared radiation and convective air utilizing an infrared/purge gas design that enables improved temperature control to enable more uniform treatment of workpieces. The furnace utilizes lamps, the electrical end connections of which are located in an enclosure outside the furnace chamber, with the lamps extending into the furnace chamber through openings in the wall of the chamber. The enclosure is purged with gas, which gas flows from the enclosure into the furnace chamber via the openings in the wall of the chamber so that the gas flows above and around the lamps and is heated to form a convective mechanism in heating parts.

  16. The kinetics of low-temperature electron-phonon relaxation in a metallic film following instantaneous heating of the electrons

    International Nuclear Information System (INIS)

    Bezuglyi, A.I.; Shklovskii, V.A.

    1997-01-01

    The theoretical analysis of experiments on pulsed laser irradiation of metallic films sputtered on insulating supports is usually based on semiphenomenological dynamical equations for the electron and phonon temperatures, an approach that ignores the nonuniformity and the nonthermal nature of the phonon distribution function. In this paper we discuss a microscopic model that describes the dynamics of the electron-phonon system in terms of kinetic equations for the electron and phonon distribution functions. Such a model provides a microscopic picture of the nonlinear energy relaxation of the electron-phonon system of a rapidly heated film. We find that in a relatively thick film the energy relaxation of electrons consists of three stages: the emission of nonequilibrium phonons by 'hot' electrons, the thermalization of electrons and phonons due to phonon reabsorption, and finally the cooling of the thermalized electron-phonon system as a result of phonon exchange between film and substrate. In thin films, where there is no reabsorption of nonequilibrium phonons, the energy relaxation consists of only one stage, the first. The relaxation dynamics of an experimentally observable quantity, the phonon contribution to the electrical conductivity of the cooling film, is directly related to the dynamics of the electron temperature, which makes it possible to use the data of experiments on the relaxation of voltage across films to establish the electron-phonon and phonon-electron collision times and the average time of phonon escape from film to substrate

  17. Systematic Studies on Anharmonicity of Rattling Phonons in Type I Clathrates by Low Temperature Heat Capacity Measurements

    Science.gov (United States)

    Tanigaki, Katsumi; Wu, Jiazhen; Tanabe, Yoichi; Heguri, Satoshi; Shiimotani, Hidekazu; Tohoku University Collaboration

    2014-03-01

    Clathrates are featured by cage-like polyhedral hosts mainly composed of the IVth group elements of Si, Ge, or Sn and alkali metal or alkaline-earth metal elements can be accommodated inside as a guest atom. One of the most intriguing issues in clathrates is their outstanding high thermoelectric performances thanks to the low thermal conductivity. Being irrespective of good electric conductivity σ, the guest atom motions provide a low-energy lying less-dispersive phonons and can greatly suppress thermal conductivity κ. This makes clathrates close to the concept of ``phonon glass electron crystal: PGEC'' and useful in thermoelectric materials from the viewpoint of the figure of merit. In the present study, we show that the local phonon anharmonicity indicated by the tunneling-term of the endohedral atoms (αT) and the itinerant-electron term (γeT), both of which show T-linear dependences in specific heat Cp, can successfully be separated by employing single crystals with various carrier concentrations in a wide range of temperture experimennts. The factors affecting on the phonon anharmonicity as well as the strength of electron-phonon interactions will be discussed based on our recent experiments. The research was financially supported by Ministry of Education, Science, Sports and Culture, Grant in Aid for Science, and Technology of Japan.

  18. Replacing critical radiators to increase the potential to use low-temperature district heating – A case study of 4 Danish single-family houses from the 1930s

    International Nuclear Information System (INIS)

    Østergaard, Dorte Skaarup; Svendsen, Svend

    2016-01-01

    Low-temperature district heating is a promising technology for providing homes with energy-efficient heating in the future. However, it is of great importance to maintain thermal comfort in existing buildings when district heating temperatures are lowered. This case study evaluated the actual radiator sizes and heating demands in 4 existing Danish single-family houses from the 1930s. A year-long dynamic simulation was performed for each of the houses to evaluate the potential to lower the heating system temperatures. The results indicate that there is a large potential to use low-temperature district heating in existing single-family houses. In order to obtain the full potential of low-temperature district heating, critical radiators must be replaced. Based on a novel method, a total of nine radiators were identified to be critical to ensure thermal comfort and low return temperatures in two of the case-houses. If these radiators were replaced it would be possible to lower the average heating system temperatures to 50 °C/27 °C in all four houses. - Highlights: • Comparison of dynamically calculated heat demands and radiator sizes. • Method for identification and evaluation of critical radiators was tested. • Existing houses can be heated with low-temperature heating for most of the year. • Replacing critical radiators helps ensure comfort and low return temperatures.

  19. Replacing critical radiators to increase the potential to use low-temperature district heating – A case study of 4 Danish single-family houses from the 1930s

    DEFF Research Database (Denmark)

    Østergaard, Dorte Skaarup; Svendsen, Svend

    2016-01-01

    radiator sizes and heating demands in 4 existing Danish single-family houses from the 1930s. A year-long dynamic simulation was performed for each of the houses to evaluate the potential to lower the heating system temperatures. The results indicate that there is a large potential to use low......-temperature district heating in existing single-family houses. In order to obtain the full potential of low-temperature district heating, critical radiators must be replaced. Based on a novel method, a total of nine radiators were identified to be critical to ensure thermal comfort and low return temperatures in two...

  20. Decentralised treatment of concentrated sewage at low temperature in a two-step anaerobic system: two upflow-hybrid septic tanks

    NARCIS (Netherlands)

    Elmitwally, T.A.; Sayed, S.; Groendijk, L.; Lier, van J.B.; Zeeman, G.; Lettinga, G.

    2003-01-01

    The decentralised treatment of concentrated sewage (about 3,600 mgCOD/1) at low temperature was investigated in a two-step anaerobic system: two-anaerobic hybrid (AH) septic tanks (each 0.575 m(3)). The two reactors were placed in a temperature controlled-room and the HRT was 2.5 days for each

  1. Chemical structure changes in coals after low-temperature oxidation and demineralization by acid treatment as revealed by high resolution solid state 13C NMR

    International Nuclear Information System (INIS)

    Tekely, P.; Nicole, D.; Delpuech, J.-J.; Totino, E.; Muller, J.F.

    1987-01-01

    13 C CP/MAS NMR has been used for characterization of chemical structure changes in coals after low-temperature oxidation and prolonged demineralization by acid treatment. In both cases the changes take place mainly in the aliphatic part of coal molecules. 21 refs.; 3 figs.; 2 tabs

  2. Low-temperature heat capacities and thermodynamic properties of ethylenediammonium tetrachlorozincate chloride (C2H10N2)2(ZnCl4)Cl2

    International Nuclear Information System (INIS)

    He, Dong-Hua; Di, You-Ying; Wang, Bin; Dan, Wen-Yan; Tan, Zhi-Cheng

    2010-01-01

    The ethylenediammonium tetrachlorozincate chloride (C 2 H 10 N 2 ) 2 (ZnCl 4 )Cl 2 was synthesized. Chemical analysis, elemental analysis, and X-ray crystallography were applied to characterize the composition and crystal structure of the complex. Low-temperature heat capacities of the compound were measured by a precision automatic adiabatic calorimeter over the temperature range from T = 77-377 K. A polynomial equation of heat capacities as a function of the reduced temperature was fitted by a least square method. Based on the polynomial equation, the smoothed heat capacities and thermodynamic functions of the title compound relative to the standard reference temperature 298.15 K were calculated at intervals of 5 K. A thermochemical cycle was designed and the enthalpy change of the solid phase reaction of ethylenediamine dihydrochloride with zinc chloride was determined to be Δ r H m o =-(17.9±0.6)kJmol -1 by an isoperibol solution-reaction calorimeter. Finally, the standard molar enthalpy of formation of the title compound was derived to be Δ f H m o [(C 2 H 10 N 2 ) 2 (ZnCl 4 )Cl 2 ,s]=-(1514.4±2.7)kJmol -1 in accordance with Hess law.

  3. Mössbauer spectroscopy, magnetization, magnetic susceptibility, and low temperature heat capacity of α-Na2NpO4

    International Nuclear Information System (INIS)

    Smith, Anna L; Hen, Amir; Magnani, Nicola; Colineau, Eric; Griveau, Jean-Christophe; Raison, Philippe E; Caciuffo, Roberto; Konings, Rudy J M; Sanchez, Jean-Pierre; Cheetham, Anthony K

    2016-01-01

    The physical and chemical properties at low temperatures of hexavalent disodium neptunate α-Na 2 NpO 4 are investigated for the first time in this work using Mössbauer spectroscopy, magnetization, magnetic susceptibility, and heat capacity measurements. The Np(VI) valence state is confirmed by the isomer shift value of the Mössbauer spectra, and the local structural environment around the neptunium cation is related to the fitted quadrupole coupling constant and asymmetry parameters. Moreover, magnetic hyperfine splitting is reported below 12.5 K, which could indicate magnetic ordering at this temperature. This interpretation is further substantiated by the existence of a λ-peak at 12.5 K in the heat capacity curve, which is shifted to lower temperatures with the application of a magnetic field, suggesting antiferromagnetic ordering. However, the absence of any anomaly in the magnetization and magnetic susceptibility data shows that the observed transition is more intricate. In addition, the heat capacity measurements suggest the existence of a Schottky-type anomaly above 15 K associated with a low-lying electronic doublet found about 60 cm −1 above the ground state doublet. The possibility of a quadrupolar transition associated with a ground state pseudoquartet is thereafter discussed. The present results finally bring new insights into the complex magnetic and electronic peculiarities of α-Na 2 NpO 4 . (paper)

  4. Heat flux estimate of warm water flow in a low-temperature diffuse flow site, southern East Pacific Rise 17°25‧ S

    Science.gov (United States)

    Goto, Shusaku; Kinoshita, Masataka; Mitsuzawa, Kyohiko

    2003-09-01

    A low-temperature diffuse flow site associated with abundant vent fauna was found by submersible observations on the southern East Pacific Rise at 17°25‧ S in 1997. This site was characterized by thin sediment covered pillow and sheet lavas with collapsed pits up to ˜15 m in diameter. There were three warm water vents (temperature: 6.5 to 10.5 °C) within the site above which the vented fluids rise as plumes. To estimate heat flux of the warm water vents, a temperature logger array was deployed and the vertical temperature distribution in the water column up to 38 m above the seafloor was monitored. A stationary deep seafloor observatory system was also deployed to monitor hydrothermal activity in this site. The temperature logger array measured temperature anomalies, while the plumes from the vents passed through the array. Because the temperature anomalies were measured in only specific current directions, we identified one of the vents as the source. Heat flux from the vent was estimated by applying a plume model in crossflow in a density-stratified environment. The average heat flux from September 13 to October 18, 1997 was 39 MW. This heat flux is as same order as those of high-temperature black smokers, indicating that a large volume flux was discharged from the vent (1.9 m3/s). Previous observations found many similar warm water flow vents along the spreading axis between 17°20‧ S 30‧ S. The total heat flux was estimated to be at least a few hundred mega-watts. This venting style would contribute to form effluent hydrothermal plumes extended above the spreading axis.

  5. Performance of a combined cooling heating and power system with mid-and-low temperature solar thermal energy and methanol decomposition integration

    International Nuclear Information System (INIS)

    Xu, Da; Liu, Qibin; Lei, Jing; Jin, Hongguang

    2015-01-01

    Highlights: • A new middle-and-low temperature solar thermochemical CCHP system is proposed. • The thermodynamic performances of the new system are numerically evaluated. • The superiorities of the new system are demonstrated. - Abstract: In this paper, a new distributed energy system that integrates the mid-and-low temperature solar energy thermochemical process and the methanol decomposition is proposed. Through the solar energy receiver/reactor, the energy collected by a parabolic trough concentrator, at 200–300 °C, is used to drive the decomposition reaction of the methanol into the synthesis gas, and thus the solar thermal energy is converted to the chemical energy. The chemical energy of the synthesis gas released in the combustion chamber of a micro gas turbine is used to drive the combined cooling heating and power systems. Energy analysis and exergy analysis of the system are implemented to evaluate the feasibility of the proposed system. Under the considerations of the changes of the solar irradiation intensity, the off-design performances of the micro turbine and the variations of the load, the design and off-design thermodynamic performances of the system and the characteristics of the chemical energy storage are numerically studied. Numerical results indicate that the primary energy ratio of the system is 76.40%, and the net solar-electricity conversion rate reaches 22.56%, which is higher than exiting large-scale solar thermal power plants. Owing to the introduction of a the solar thermochemical energy storage in the proposed system, the power generation efficiency is insensitive to the variations of the solar radiation, and thus an efficient and stable utilization approach of the solar thermal energy is achieved at all work condition

  6. Study of critical free-area ratio during the snow-melting process on pavement using low-temperature heating fluids

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Huajun [School of Energy and Environment Engineering, Hebei University of Technology, Tianjin 300401 (China); Chen, Zhihao [Faculty of Engineering, Yokohama National University, Hodogaya, Yokohama 240-8501 (Japan)

    2009-01-15

    Critical free-area ratio (CFR) is an interesting phenomenon during the snow-melting process on pavement using low-temperature heating fluids such as geothermal tail water and industrial waste water. This paper is performed to further investigate the mechanism of CFR and its influencing factors. A simplified theoretical model is presented to describe the heat and mass transfer process on pavement. Especially the variation of thermal properties and the capillary effect of snow layer are considered. Numerical computation shows that the above theoretical model is effective for the prediction of CFR during the snow-melting process. Furthermore, the mechanism of CFR is clarified in detail. CFR is independent of the layout of hydronic pipes, the fluid temperature, the idling time, and weather conditions. It is both the non-uniform temperature distribution and complicated porous structure of snow layer that lead to the occurrence of CFR. Besides, the influences of operation parameters including the fluid temperature, the idling time, the pipe spacing and buried depths on snow melting are analyzed, which are helpful for the next optimal design of snow-melting system. (author)

  7. Study of critical free-area ratio during the snow-melting process on pavement using low-temperature heating fluids

    Energy Technology Data Exchange (ETDEWEB)

    Wang Huajun [School of Energy and Environment Engineering, Hebei University of Technology, Tianjin 300401 (China)], E-mail: huajunwang@126.com; Chen Zhihao [Faculty of Engineering, Yokohama National University, Hodogaya, Yokohama 240-8501 (Japan)

    2009-01-15

    Critical free-area ratio (CFR) is an interesting phenomenon during the snow-melting process on pavement using low-temperature heating fluids such as geothermal tail water and industrial waste water. This paper is performed to further investigate the mechanism of CFR and its influencing factors. A simplified theoretical model is presented to describe the heat and mass transfer process on pavement. Especially the variation of thermal properties and the capillary effect of snow layer are considered. Numerical computation shows that the above theoretical model is effective for the prediction of CFR during the snow-melting process. Furthermore, the mechanism of CFR is clarified in detail. CFR is independent of the layout of hydronic pipes, the fluid temperature, the idling time, and weather conditions. It is both the non-uniform temperature distribution and complicated porous structure of snow layer that lead to the occurrence of CFR. Besides, the influences of operation parameters including the fluid temperature, the idling time, the pipe spacing and buried depths on snow melting are analyzed, which are helpful for the next optimal design of snow-melting system.

  8. Study of critical free-area ratio during the snow-melting process on pavement using low-temperature heating fluids

    International Nuclear Information System (INIS)

    Wang Huajun; Chen Zhihao

    2009-01-01

    Critical free-area ratio (CFR) is an interesting phenomenon during the snow-melting process on pavement using low-temperature heating fluids such as geothermal tail water and industrial waste water. This paper is performed to further investigate the mechanism of CFR and its influencing factors. A simplified theoretical model is presented to describe the heat and mass transfer process on pavement. Especially the variation of thermal properties and the capillary effect of snow layer are considered. Numerical computation shows that the above theoretical model is effective for the prediction of CFR during the snow-melting process. Furthermore, the mechanism of CFR is clarified in detail. CFR is independent of the layout of hydronic pipes, the fluid temperature, the idling time, and weather conditions. It is both the non-uniform temperature distribution and complicated porous structure of snow layer that lead to the occurrence of CFR. Besides, the influences of operation parameters including the fluid temperature, the idling time, the pipe spacing and buried depths on snow melting are analyzed, which are helpful for the next optimal design of snow-melting system

  9. Thermo-Economic and Heat Transfer Optimization of Working-Fluid Mixtures in a Low-Temperature Organic Rankine Cycle System

    Directory of Open Access Journals (Sweden)

    Oyeniyi A. Oyewunmi

    2016-06-01

    Full Text Available In the present paper, we consider the employment of working-fluid mixtures in organic Rankine cycle (ORC systems with respect to thermodynamic and heat-transfer performance, component sizing and capital costs. The selected working-fluid mixtures promise reduced exergy losses due to their non-isothermal phase-change behaviour, and thus improved cycle efficiencies and power outputs over their respective pure-fluid components. A multi-objective cost-power optimization of a specific low-temperature ORC system (operating with geothermal water at 98 °C reveals that the use of working-fluid-mixtures does indeed show a thermodynamic improvement over the pure-fluids. At the same time, heat transfer and cost analyses, however, suggest that it also requires larger evaporators, condensers and expanders; thus, the resulting ORC systems are also associated with higher costs. In particular, 50% n-pentane + 50% n-hexane and 60% R-245fa + 40% R-227ea mixtures lead to the thermodynamically optimal cycles, whereas pure n-pentane and pure R-245fa have lower plant costs, both estimated as having ∼14% lower costs per unit power output compared to the thermodynamically optimal mixtures. These conclusions highlight the importance of using system cost minimization as a design objective for ORC plants.

  10. Benefits of applying low-temperature plasma treatment to wound care and hemostasis from the viewpoints of physics and pathology

    Science.gov (United States)

    Shimizu, Tetsuji; Ikehara, Yuzuru

    2017-12-01

    Over the last decade, low-temperature plasma (LTP) technology has reached the life sciences and introduced the benefits of using such technology at atmospheric pressure for medical applications. The active elements from LTP, such as reactive molecular species, charged particles and photons, appear to react with biomolecules on wounds and at bleeding points. This action by LTP might be analogous with semiconductor fabrication techniques such as etching and surface modification. From this perspective, we discuss the general aspects and principles of LTP devices used at atmospheric pressure in wound care and hemostasis as an interdisciplinary fusion of applied physics and pathology.

  11. Energy density and storage capacity cost comparison of conceptual solid and liquid sorption seasonal heat storage systems for low-temperature space heating

    NARCIS (Netherlands)

    Scapino, L.; Zondag, H.A.; Van Bael, J.; Diriken, J.; Rindt, C.C.M.

    Sorption heat storage can potentially store thermal energy for long time periods with a higher energy density compared to conventional storage technologies. A performance comparison in terms of energy density and storage capacity costs of different sorption system concepts used for seasonal heat

  12. Automatic low-temperature calorimeter

    International Nuclear Information System (INIS)

    Malyshev, V.M.; Mil'ner, G.A.; Shibakin, V.F.; Sorkin, E.L.

    1986-01-01

    This paper describes a low-temperature adiabatic calorimeter with a range of 1.5-500K. The system for maintaining adiabatic conditions is implemented by two resitance thermometers, whose sensitivity at low temperatures is several orders higher than that of thermocouples. The calorimeter cryostat is installed in an STG-40 portable Dewar flask. The calorimeter is controlled by an Elektronika-60 microcomputer. Standard platinum and germanium thermometers were placed inside of the calorimeter to calibrate the thermometers of the calorimeter and the shield, and the specific heats of specimens of OSCh 11-4 copper and KTP-8 paste were measured to demonstrate the possibilities of the described calorimeter. Experience with the calorimeter has shown that a thorough study of the dependence of heat capacity on temperature (over 100 points for one specimen) can be performed in one or two dats

  13. Low-temperature molar heat capacities and entropies of MnO2 (pyrolusite), Mn3O4 (hausmanite), and Mn2O3 (bixbyite)

    Science.gov (United States)

    Robie, R.A.; Hemingway, B.S.

    1985-01-01

    Pyrolusite (MnO2), hausmanite (Mn3O4), and bixbyite (Mn2O3), are important ore minerals of manganese and accurate values for their thermodynamic properties are desirable to understand better the {p(O2), T} conditions of their formation. To provide accurate values for the entropies of these important manganese minerals, we have measured their heat capacities between approximately 5 and 380 K using a fully automatic adiabatically-shielded calorimeter. All three minerals are paramagnetic above 100 K and become antiferromagnetic or ferrimagnetic at lower temperatures. This transition is expressed by a sharp ??-type anomaly in Cpmo for each compound with Ne??el temperatures TN of (92.2??0.2), (43.1??0.2), and (79.45??0.05) K for MnO2, Mn3O4, and Mn2O3, respectively. In addition, at T ??? 308 K, Mn2O3 undergoes a crystallographic transition, from orthorhombic (at low temperatures) to cubic. A significant thermal effect is associated with this change. Hausmanite is ferrimagnetic below TN and in addition to the normal ??-shape of the heat-capacity maxima in MnO2 and Mn2O3, it has a second rounded maximum at 40.5 K. The origin of this subsidiary bump in the heat capacity is unknown but may be related to a similar "anomalous bump" in the curve of magnetization against temperature at about 39 K observed by Dwight and Menyuk.(1) At 298.15 K the standard molar entropies of MnO2, Mn3O4, and Mn2O3, are (52.75??0.07), (164.1??0.2), and (113.7??0.2) J??K-1??mol-1, respectively. Our value for Mn3O4 is greater than that adopted in the National Bureau of Standards tables(2) by 14 per cent. ?? 1985.

  14. Synthesis and Characterization of Si Oxide Coated Nano Ceria by Hydrolysis, and Hydrothermal Treatment at Low Temperature

    Directory of Open Access Journals (Sweden)

    Kong M.

    2017-06-01

    Full Text Available The purpose of this work was to the application of Si oxide coatings. This study deals with the preparation of ceria (CeO2 nanoparticles coating with SiO2 by water glass and hydrolysis reaction. First, the low temperature hydro-reactions were carried out at 30~100°C. Second, Silicon oxide-coated Nano compounds were obtained by the catalyzing synthesis. CeO2 Nano-powders have been successfully synthesized by means of the hydrothermal method, in a low temperature range of 100~200°C. In order to investigate the structure and morphology of the Nano-powders, scanning electron microscopy (SEM and X-ray diffraction (XRD were employed. The XRD results revealed the amorphous nature of silica nanoparticles. To analyze the quantity and properties of the compounds coated with Si oxide, transmission electron microscopy (TEM in conjunction with electron dispersive spectroscopy was used. Finally, it is suggested that the simple growth process is more favorable mechanism than the solution/aggregation process.

  15. Thermodynamic effects when utilizing waste heat from condensation in cases of a reduced vacuum in steam turbine plants of thermal power stations, to provide heat at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Vasiljevic, N.; Savic, B.; Stojakovic, M.

    1986-01-01

    There is an interesting variant of cogeneration in the steam turbine system of a thermal power plant, i.e. the utilisation of the waste heat of condensation with a reduced vacuum without reconstruction of the thermal power plant. The thermodynamic effect in cogeneration was calculated in consideration of the dynamics of heat consumption. This cogeneration process has the advantage of saving primary energy without reconstruction of the thermal power plant.

  16. Effects of short-range order on electronic properties of Zr-Ni glasses as seen from low-temperature specific heat

    International Nuclear Information System (INIS)

    Kroeger, D.M.; Koch, C.C.; Scarbrough, J.O.; McKamey, C.G.

    1984-01-01

    Measurements of the low-temperature specific heat C/sub p/ of liquid-quenched Zr-Ni glasses for a large number of compositions in the range from 55 to 74 at. % Zr revealed an unusual composition dependence of the density of states at the Fermi level, N(E/sub F/). Furthermore, for some compositions the variation of C/sub p/ near the superconducting transition temperature T/sub c/ indicated the presence of two superconducting phases, i.e., two superconducting transitions were detected. Comparison of the individual T/sub c/'s in phase-separated samples to the composition dependence of T/sub c/ for all of the samples suggests that amorphous phases with compositions near 60 and 66.7 at. % Zr occur. We discuss these results in terms of an ''association model'' for liquid alloys (due to Sommer), in which associations of unlike atoms with definite stoichiometries are assumed to exist in equilibrium with unassociated atoms. We conclude that in the composition range studied, associate clusters with the compositions Zr 3 Ni 2 and Zr 2 Ni occur. In only a few cases are the clusters sufficiently large, compared with the superconducting coherence length, for separate superconducting transitions to be observed. The variation of N(E/sub F/) with composition is discussed, as well as the effects of this chemical short-range ordering on the crystallization behavior and glass-forming tendency

  17. Effects of short-range order on electronic properties of Zr-Ni glasses as seen from low-temperature specific heat

    Science.gov (United States)

    Kroeger, D. M.; Koch, C. C.; Scarbrough, J. O.; McKamey, C. G.

    1984-02-01

    Measurements of the low-temperature specific heat Cp of liquid-quenched Zr-Ni glasses for a large number of compositions in the range from 55 to 74 at.% Zr revealed an unusual composition dependence of the density of states at the Fermi level, N(EF). Furthermore, for some compositions the variation of Cp near the superconducting transition temperature Tc indicated the presence of two superconducting phases, i.e., two superconducting transitions were detected. Comparison of the individual Tc's in phase-separated samples to the composition dependence of Tc for all of the samples suggests that amorphous phases with compositions near 60 and 66.7 at.% Zr occur. We discuss these results in terms of an "association model" for liquid alloys (due to Sommer), in which associations of unlike atoms with definite stoichiometries are assumed to exist in equilibrium with unassociated atoms. We conclude that in the composition range studied, associate clusters with the compositions Zr3Ni2 and Zr2Ni occur. In only a few cases are the clusters sufficiently large, compared with the superconducting coherence length, for separate superconducting transitions to be observed. The variation of N(EF) with composition is discussed, as well as the effects of this chemical short-range ordering on the crystallization behavior and glass-forming tendency.

  18. Research and Development of a New Field Enhanced Low Temperature Thermionic Cathode that Enables Fluorescent Dimming and Loan Shedding without Auxiliary Cathode Heating

    Energy Technology Data Exchange (ETDEWEB)

    Feng Jin

    2009-01-07

    This is the final report for project entitled 'Research and development of a new field enhanced low temperature thermionic cathode that enables fluorescent dimming and load shedding without auxiliary cathode heating', under Agreement Number: DE-FC26-04NT-42329. Under this project, a highly efficient CNT based thermionic cathode was demonstrated. This cathode is capable of emitting electron at a current density two order of magnitude stronger then a typical fluorescent cathode at same temperatures, or capable of emitting at same current density but at temperature about 300 C lower than that of a fluorescent cathode. Detailed fabrication techniques were developed including CVD growth of CNTs and sputter deposition of oxide thin films on CNTs. These are mature technologies that have been widely used in industry for large scale materials processing and device fabrications, thus, with further development work, the techniques developed in this project can be scaled-up in manufacturing environment. The prototype cathodes developed in this project were tested in lighting plasma discharge environment. In many cases, they not only lit and sustain the plasma, but also out perform the fluorescent cathodes in key parameters such like cathode fall voltages. More work will be needed to further evaluate more detailed and longer term performance of the prototype cathode in lighting plasma.

  19. A hybrid geothermal energy conversion technology: Auxiliary heating of geothermally preheated water or CO2 - a potential solution for low-temperature resources

    Science.gov (United States)

    Saar, Martin; Garapati, Nagasree; Adams, Benjamin; Randolph, Jimmy; Kuehn, Thomas

    2016-04-01

    Safe, sustainable, and economic development of deep geothermal resources, particularly in less favourable regions, often requires employment of unconventional geothermal energy extraction and utilization methods. Often "unconventional geothermal methods" is synonymously and solely used as meaning enhanced geothermal systems, where the permeability of hot, dry rock with naturally low permeability at greater depths (4-6 km), is enhanced. Here we present an alternative unconventional geothermal energy utilization approach that uses low-temperature regions that are shallower, thereby drastically reducing drilling costs. While not a pure geothermal energy system, this hybrid approach may enable utilization of geothermal energy in many regions worldwide that can otherwise not be used for geothermal electricity generation, thereby increasing the global geothermal resource base. Moreover, in some realizations of this hybrid approach that generate carbon dioxide (CO2), the technology may be combined with carbon dioxide capture and storage (CCS) and CO2-based geothermal energy utilization, resulting in a high-efficiency (hybrid) geothermal power plant with a negative carbon footprint. Typically, low- to moderate-temperature geothermal resources are more effectively used for direct heat energy applications. However, due to high thermal losses during transport, direct use requires that the heat resource is located near the user. Alternatively, we show here that if such a low-temperature geothermal resource is combined with an additional or secondary energy resource, the power production is increased compared to the sum from two separate (geothermal and secondary fuel) power plants (DiPippo et al. 1978) and the thermal losses are minimized because the thermal energy is utilized where it is produced. Since Adams et al. (2015) found that using CO2 as a subsurface working fluid produces more net power than brine at low- to moderate-temperature geothermal resource conditions, we

  20. Group theoretical treatment of the low-temperature phase transition of the Cd6Ca 1/1-cubic approximant

    International Nuclear Information System (INIS)

    Tamura, R.; Shibata, K.; Nishimoto, K.; Takeuchi, S.; Edagawa, K.; Saitoh, K.; Isobe, M.; Ueda, Y.

    2005-01-01

    An antiparallel orientational transition is reported for an intermetallic compound, i.e., Cd 6 Ca crystal, which is a 1/1-1/1-1/1 crystalline approximant to the icosahedral quasicrystal Cd 5.7 Ca. A group theoretical analysis based on the Landau theory predicts that the space group of the low-temperature phase is either C2/c or C2/m, in good agreement with the observations. Accordingly, two types of orientational orderings of Cd 4 tetrahedra, which are located in the center of icosahedral clusters, may occur below 100 K: In both cases, the Cd 4 tetrahedra are orientationally ordered in an antiparallel fashion along the [110] direction of the high temperature body-centered-cubic phase. Such a transition in a metal is reminiscent of orientational transitions in molecular solids

  1. A Total Cost of Ownership Model for Low Temperature PEM Fuel Cells in Combined Heat and Power and Backup Power Applications

    Energy Technology Data Exchange (ETDEWEB)

    University of California, Berkeley; Wei, Max; Lipman, Timothy; Mayyas, Ahmad; Chien, Joshua; Chan, Shuk Han; Gosselin, David; Breunig, Hanna; Stadler, Michael; McKone, Thomas; Beattie, Paul; Chong, Patricia; Colella, Whitney; James, Brian

    2014-06-23

    A total cost of ownership model is described for low temperature proton exchange membrane stationary fuel cell systems for combined heat and power (CHP) applications from 1-250kW and backup power applications from 1-50kW. System designs and functional specifications for these two applications were developed across the range of system power levels. Bottom-up cost estimates were made for balance of plant costs, and detailed direct cost estimates for key fuel cell stack components were derived using design-for-manufacturing-and-assembly techniques. The development of high throughput, automated processes achieving high yield are projected to reduce the cost for fuel cell stacks to the $300/kW level at an annual production volume of 100 MW. Several promising combinations of building types and geographical location in the U.S. were identified for installation of fuel cell CHP systems based on the LBNL modelling tool DER CAM. Life-cycle modelling and externality assessment were done for hotels and hospitals. Reduced electricity demand charges, heating credits and carbon credits can reduce the effective cost of electricity ($/kWhe) by 26-44percent in locations such as Minneapolis, where high carbon intensity electricity from the grid is displaces by a fuel cell system operating on reformate fuel. This project extends the scope of existing cost studies to include externalities and ancillary financial benefits and thus provides a more comprehensive picture of fuel cell system benefits, consistent with a policy and incentive environment that increasingly values these ancillary benefits. The project provides a critical, new modelling capacity and should aid a broad range of policy makers in assessing the integrated costs and benefits of fuel cell systems versus other distributed generation technologies.

  2. Administration of a Sol-Gel Formulation of Phenylephrine Using Low-Temperature Hollow Microneedle for Treatment of Intermittent Fecal Incontinence.

    Science.gov (United States)

    Lee, Hyunji; Park, Jung-Hwan; Park, Jung Ho

    2017-12-01

    A low temperature hollow microneedle system was devised to deliver sol-gel transition formulation near the surface of the skin for extended release and local delivery of drug by a non-invasive method. This new system can improve treatment of intermittent fecal incontinence. The low-temperature system was integrated with a hollow microneedle to maintain the low temperature of the sol formulation. Various sol-gel formulations using Pluronic F-127 (PF-127) and Hydroxy-propyl-methyl-cellulose (HPMC) were prepared, and their gelation temperature, flow property, and diffusion retardation were observed. Resting anal sphincter pressure in response to a phenylephrine (PE) sol-gel formulation was measured using an air-charged catheter. The biocompatibility of the sol-gel PE formulation was evaluated by observing the immunological response. When the PF-127 25%, HPMC 1% and PE formulation (PF25-HPMC1-PE) was injected through the peri-anal skin of the rat in vivo, the highest pressure on the anal sphincter muscle occurred at 6-8 h and anal pressure increased and lasted twice as long as with the phosphate-buffered saline (PBS)-PE formulation. There was no significant difference in the number of mast cells after administration into the rat in vivo between the PF25-HPMC1-PE formulation and the PBS-PE formulation. The combination of a low-pain hollow microneedle system and an injectable sol-gel formulation improved the efficacy of treatment of intermittent fecal incontinence. A low-temperature hollow microneedle system using a sol-gel formulation has many applications in medical treatments that require depot effect, local targeting, and pain control.

  3. Thermoluminescent system for low temperatures

    International Nuclear Information System (INIS)

    Rosa, L.A.R. da; Caldas, L.V.E.; Leite, N.G.

    1988-09-01

    A system for measurements of the thermoluminescent glow curve, the thermoluminescent emission spectrum and the optical absorption spectrum of solid samples, from liquid nitrogen temperature up to 473 K, is reported. A specially designed temperature programmer provides a linear heating of the sample at a wide range of selectable heating rates, as also long term steady-state temperatures for annealing and isothermal decay studies. The system operates at a pressure of 1.33 x 10 -3 Pa. Presently it is being used for lithium fluoride low temperature thermoluminescent studies. (author) [pt

  4. Miscellaneous investigations. Subreport 3; CO{sub 2}-reductions in low-energy buildings and communities by implementation of low-temperature district heating systems

    Energy Technology Data Exchange (ETDEWEB)

    Brand, M. (DTU-BYG, Kgs. Lyngby (Denmark)); Kaarup Olsen, P. (COWI A/S, Kgs. Lyngby (Denmark))

    2011-05-15

    The report focuses on possibilities of how to further decrease CO{sub 2} emissions by implementation of low-temperature district heating (LTDH) in areas with new low-energy buildings as well as in areas with existing buildings. In the first chapter, three different sites where LTDH is considered are reported. The first site is in Solbjerg near Aarhus, where 104 low-energy single-family houses are planned to be built. Calculations for a LTDH network (60/30 deg. C) have been made in the program TERMIS. The results show that depending on the houses being built as low-energy class 1 or 2, a cost saving potential of 6-13% can be achieved compared to traditional district heating (DH). The CO{sub 2}-reduction potential is 4.4-7.5 tonnes per year. The second reported site is an area with single-family houses built in the 1970s in Skjoldhoejparken in Tilst near Aarhus. Eight single-family houses have been investigated. Refurbishment can reduce the heat demand and make the houses more suitable for LTDH, but even with subsidy it is difficult to motivate the building owners to make energy saving initiatives. Analyses show that if the DH supply temperature is lowered gradually from 80 deg. C to 60 deg. C, depending on the outdoor temperature, the heat loss in the existing pipe network for the eight houses can be reduced by 20%. An even larger potential can be achieved with replacement of the existing pipe system. The third site is neighbourhood in Soenderby in Hoeje Taastrup with 75 single-family houses from the 1990s. The existing DH network is poor and has a heat loss of more than 40%. With LTDH it will be possible to reduce the network heat loss to 15% or lower. The CO{sub 2}-emission could be reduced by about 66 tonnes per year. In the second chapter are described existing district heating systems in Aarhus and Hoeje Taastrup. The average DH temperature is currently 80-77/47-42 deg. C, so there is a potential for LTDH. The network heat loss in the DH systems is 15

  5. Fuel oil from low-temperature carbonization of coal

    Energy Technology Data Exchange (ETDEWEB)

    Thau, A

    1941-01-01

    A review has been given of German developments during the last 20 years. Four methods for the low-temperature carbonization of coal have been developed to the industrial stage; two involving the use of externally heated, intermittent, metallic chamber ovens; and two employing the principle of internal heating by means of a current of gas. Tar from externally heated retorts can be used directly as fuel oil, but that from internally heated retorts requires further treatment. In order to extend the range of coals available for low-temperature carbonization, and to economize metals, an externally heated type of retort constructed of ceramic material has been developed to the industrial stage by T. An excellent coke and a tar that can be used directly as fuel oil are obtained. The properties of the tar obtained from Upper Silesian coal are briefly summarized.

  6. WORKSHOP: Low temperature devices

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    With extraterrestrial neutrinos (whether from the sun or further afield) continuing to make science news, and with the search for the so far invisible 'dark matter' of the universe a continual preoccupation, physicists from different walks of life (solid state, low temperature, particles, astrophysics) gathered at a workshop on low temperature devices for the detection of neutrinos and dark matter, held from 12-13 March at Ringberg Castle on Lake Tegernsee in the Bavarian Alps, and organized by the Max Planck Institute for Physics and Astrophysics in Munich

  7. WORKSHOP: Low temperature devices

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1987-06-15

    With extraterrestrial neutrinos (whether from the sun or further afield) continuing to make science news, and with the search for the so far invisible 'dark matter' of the universe a continual preoccupation, physicists from different walks of life (solid state, low temperature, particles, astrophysics) gathered at a workshop on low temperature devices for the detection of neutrinos and dark matter, held from 12-13 March at Ringberg Castle on Lake Tegernsee in the Bavarian Alps, and organized by the Max Planck Institute for Physics and Astrophysics in Munich.

  8. Plasma treatment of heat-resistant materials

    International Nuclear Information System (INIS)

    Vlasov, V A; Kosmachev, P V; Skripnikova, N K; Bezukhov, K A

    2015-01-01

    Refractory lining of thermal generating units is exposed to chemical, thermal, and mechanical attacks. The degree of fracture of heat-resistant materials depends on the chemical medium composition, the process temperature and the material porosity. As is known, a shortterm exposure of the surface to low-temperature plasma (LTP) makes possible to create specific coatings that can improve the properties of workpieces. The aim of this work is to produce the protective coating on heat-resistant chamotte products using the LTP technique. Experiments have shown that plasma treatment of chamotte products modifies the surface, and a glass-ceramic coating enriched in mullite is formed providing the improvement of heat resistance. For increasing heat resistance of chamotte refractories, pastes comprising mixtures of Bacor, alumina oxide, and chamot were applied to their surfaces in different ratios. It is proved that the appropriate coating cannot be created if only one of heat-resistant components is used. The required coatings that can be used and recommended for practical applications are obtained only with the introduction of powder chamot. The paste composition of 50% chamot, 25% Bacor, and 25% alumina oxide exposed to plasma treatment, has demonstrated the most uniform surface fusion. (paper)

  9. Influence of seed layer treatment on low temperature grown ZnO nanotubes: Performances in dye sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Ameen, Sadia [Energy Materials and Surface Science Laboratory, Solar Energy Research Center, School of Chemical Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Akhtar, M. Shaheer [School of Semiconductor and Chemical Engineering and Solar Energy Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); New and Renewable Energy Material Development Center (NewREC), Chonbuk National University, Buan-gun, Jeonbuk (Korea, Republic of); Kim, Young Soon [Energy Materials and Surface Science Laboratory, Solar Energy Research Center, School of Chemical Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Yang, O-Bong [School of Semiconductor and Chemical Engineering and Solar Energy Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Shin, Hyung-Shik, E-mail: hsshin@jbnu.ac.k [Energy Materials and Surface Science Laboratory, Solar Energy Research Center, School of Chemical Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)

    2011-01-01

    Non-aligned and highly densely aligned ZnO nanotube (NTs), synthesized by low temperature solution method were applied as photoanode materials for the fabrication of efficient dye-sensitized solar cells (DSSCs). The crystalline and the morphological analysis revealed that the grown aligned ZnO NTs possessed a typical hexagonal crystal structure of outer and inner diameter {approx}250 nm and {approx}100 nm, respectively. ZnO seeding on FTO substrates is an essential step to achieve the aligned ZnO NTs. A DSSC fabricated with aligned ZnO NTs photoanode achieved high solar-to-electricity conversion efficiency of {approx}2.2% with short circuit current (J{sub SC}) of 5.5 mA/cm{sup 2}, open circuit voltage (V{sub OC}) of 0.65 V and fill factor (FF) of 0.61. Significantly, the aligned ZnO NTs photoanode showed three times improved solar-to-electricity conversion efficiency than DSSC fabricated with non-aligned ZnO NTs. The enhanced performances were credited to the aligned morphology of ZnO NTs which executed the high charge collection and the transfer of electrons at the interfaces of ZnO NTs and electrolyte layer.

  10. Influence of Low-Temperature Plasma Treatment on The Liquid Filtration Efficiency of Melt-Blown PP Nonwovens in The Conditions of Simulated Use of Respiratory Protective Equipment

    Directory of Open Access Journals (Sweden)

    Majchrzycka Katarzyna

    2017-06-01

    Full Text Available Filtering nonwovens produced with melt-blown technology are one of the most basic materials used in the construction of respiratory protective equipment (RPE against harmful aerosols, including bio- and nanoaerosols. The improvement of their filtering properties can be achieved by the development of quasi-permanent electric charge on the fibres. Usually corona discharge method is utilized for this purpose. In the presented study, it was assumed that the low-temperature plasma treatment could be applied as an alternative method for the manufacturing of conventional electret nonwovens for the RPE construction. Low temperature plasma treatment of polypropylene nonwovens was carried out with various process gases (argon, nitrogen, oxygen or air in a wide range of process parameters (gas flow velocity, time of treatment and power supplied to the reactor electrodes. After the modification, nonwovens were evaluated in terms of filtration efficiency of paraffin oil mist. The stability of the modification results was tested after 12 months of storage and after conditioning at elevated temperature and relative humidity conditions. Moreover, scanning electron microscopy and ATR-IR spectroscopy were used to assess changes in surface topography and chemical composition of the fibres. The modification of melt-blown nonwovens with nitrogen, oxygen and air plasma did not result in a satisfactory improvement of the filtration efficiency. In case of argon plasma treatment, up to 82% increase of filtration efficiency of paraffin oil mist was observed in relation to untreated samples. This effect was stable after 12 months of storage in normal conditions and after thermal conditioning in (70 ± 3°C for 24 h. The use of low-temperature plasma treatment was proven to be a promising improvement direction of filtering properties of nonwovens used for the protection of respiratory tract against harmful aerosols.

  11. Effect of low temperature thermal pre-treatment on the solubilization of organic matter, pathogen inactivation and mesophilic anaerobic digestion of poultry sludge.

    Science.gov (United States)

    Ruiz-Espinoza, Juan E; Méndez-Contreras, Juan M; Alvarado-Lassman, Alejandro; Martínez-Delgadillo, Sergio A

    2012-01-01

    Treatment of poultry industry effluents produces wastewater sludge with high levels of organic compounds and pathogenic microorganisms. In this research, the thermal pre-treatment of poultry slaughterhouse sludge (PSS) was evaluated for low temperatures in combination with different exposure times as a pre-hydrolysis strategy to improve the anaerobic digestion process. Organic compounds solubilization and inactivation of pathogenic microorganisms were evaluated after treatment at 70, 80 or 90°C for 30, 60 or 90 min. The results showed that 90°C and 90 min were the most efficient conditions for solubilization of the organic compounds (10%). In addition, the bacteria populations and the more resistant structures, such as helminth eggs (HE), were completely inactivated. Finally, the thermal pre-treatment applied to the sludge increased methane yield by 52% and reduced hydraulic retention time (HRT) by 52%.

  12. Low temperatures - hot topic

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1988-09-15

    Neutrino mass measurements, next-generation double beta experiments, solar neutrino detection, searches for magnetic monopoles and the challenge of discovering what most of the Universe is made of (dark matter), not to mention axions (cosmic and solar), supersymmetric neutral particles and cosmic neutrinos. All this physics could use cryogenic techniques. Thus the second European Workshop on Low Temperature Devices for the Detection of Low Energy Neutrinos and Dark Matter, held at LAPP (Annecy) in May, covered an active and promising field.

  13. Low temperatures - hot topic

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    Neutrino mass measurements, next-generation double beta experiments, solar neutrino detection, searches for magnetic monopoles and the challenge of discovering what most of the Universe is made of (dark matter), not to mention axions (cosmic and solar), supersymmetric neutral particles and cosmic neutrinos. All this physics could use cryogenic techniques. Thus the second European Workshop on Low Temperature Devices for the Detection of Low Energy Neutrinos and Dark Matter, held at LAPP (Annecy) in May, covered an active and promising field

  14. Low temperature carbonization

    Energy Technology Data Exchange (ETDEWEB)

    Abbott, A A

    1934-01-10

    A process is described in which coal is passed through a distillation chamber in one retort at a comparatively low temperature, then passing the coal through a distillation chamber of a second retort subjected to a higher temperature, thence passing the coal through the distillation chamber of a third retort at a still higher temperature and separately collecting the liquid and vapors produced from each retort.

  15. Sweating at low temperature

    International Nuclear Information System (INIS)

    Chalaye, H.; Launay, J.P.

    1980-11-01

    Tests of penetration liquids normally used between 10 and 40 0 C have shown that the arrangement of operationaal conditions (penetration and revealing times) was not sufficient to maintain their sensitivity below 10 0 C, thereby confirming that this temperature is a limit below which such products cannot be employed. The results achieved with a penetrant and a tracer specially devised for low temperatures (SHERWIN B 305 + D100) are satisfactory between 0 0 C and 15 0 C [fr

  16. Treatment of a chocolate industry wastewater in a pilot-scale low-temperature UASB reactor operated at short hydraulic and sludge retention time.

    Science.gov (United States)

    Esparza-Soto, M; Arzate-Archundia, O; Solís-Morelos, C; Fall, C

    2013-01-01

    The aim of this work was to evaluate the performance of a 244-L pilot-scale upflow anaerobic sludge blanket (UASB) reactor during the treatment of chocolate-processing industry wastewater under low-temperature conditions (18 ± 0.6 °C) for approximately 250 d. The applied organic loading rate (OLR) was varied between 4 and 7 kg/m(3)/d by varying the influent soluble chemical oxygen demand (CODsol), while keeping the hydraulic retention time constant (6.4 ± 0.3 h). The CODsol removal efficiency was low (59-78%). The measured biogas production increased from 240 ± 54 to 431 ± 61 L/d during the experiments. A significant linear correlation between the measured biogas production and removed OLR indicated that 81.69 L of biogas were produced per kg/m(3) of CODsol removed. Low average reactor volatile suspended solids (VSS) (2,700-4,800 mg/L) and high effluent VSS (177-313 mg/L) were derived in a short sludge retention time (SRT) (4.9 d). The calculated SRT was shorter than those reported in the literature, but did not affect the reactor's performance. Average sludge yield was 0.20 kg-VSS/kg-CODsol. The low-temperature anaerobic treatment was a good option for the pre-treatment of chocolate-processing industry wastewater.

  17. Improvement in surface hydrophilicity and resistance to deformation of natural leather through O2/H2O low-temperature plasma treatment

    Science.gov (United States)

    You, Xuewei; Gou, Li; Tong, Xingye

    2016-01-01

    The natural leather was modified through O2/H2O low-temperature plasma treatment. Surface morphology was characterized by scanning electron microscopy (SEM) and the results showed that the pores on the leather surface became deeper and larger with enhanced permeability of water and vapor. XPS and FTIR-ATR was performed to determine the chemical composition of natural leather surface. Oxygen-containing groups were successfully grafted onto the surface of natural leather and oxygen content increased with longer treatment time. After O2/H2O plasma treatment, initial water contact angle was about 21° and water contact angles were not beyond 55° after being stored for 3 days. Furthermore, the tensile test indicated that the resistance to deformation had a prominent transform without sacrificing the tensile strength.

  18. Decentralised treatment of concentrated sewage at low temperature in a two-step anaerobic system: two upflow-hybrid septic tanks.

    Science.gov (United States)

    Elmitwalli, T A; Sayed, S; Groendijk, L; van Lier, J; Zeeman, G; Lettinga, G

    2003-01-01

    The decentralised treatment of concentrated sewage (about 3,600 mgCOD/l) at low temperature was investigated in a two-step anaerobic system: two-anaerobic hybrid (AH) septic tanks (each 0.575 m3). The two reactors were placed in a temperature controlled-room and the HRT was 2.5 days for each reactor. The system was fed with concentrated domestic sewage, mainly black water from about 40 toilets flushed with only 4 litre of water and a limited amount of grey water. The system showed high removal efficiency for the different COD fractions. Mean removal efficiencies in the two-step AH-septic tank at 5 days HRT and 13 degrees C were 94, 98, 74 and 78% for total COD, suspended COD, colloidal COD and dissolved COD respectively. The results of short run experiments indicated that the presence of reticulated polyurethane foam (RPF) media in the AH-septic tank improved the removal of suspended COD by 22%. The first AH-septic tank was full of sludge after 4 months of operation due to the high removal of particulate COD and the limited hydrolysis at low temperature conditions. Therefore, a simple mathematical model was developed based on ADM1 (the IWA model in 2002). Based on the experimental results and the mathematical model, only a one-step AH septic tank is required. An HRT of 5.5-7.5 days is needed for that one-step AH septic tank to treat concentrated sewage at a low temperature of 13 degrees C. Such a system can provide a total COD removal as high as 87% and will be full of sludge after a period of more than a year.

  19. Anaerobic pre-treatment of sewage under low temperature (15 [degrees] C) conditions in an integrated UASB-digester system

    NARCIS (Netherlands)

    Mahmoud, N.J.A.H.

    2002-01-01

    The main objective of this thesis was to amend the UASB by the means of incorporating a digester for anaerobic sewage treatment in the Middle East region.

    A literature search of the various parameters that mightaffect the solid liquid separation process by filtration

  20. Low-temperature electron properties of Heusler alloys Fe2VAl and Fe2CrAl: Effect of annealing

    International Nuclear Information System (INIS)

    Podgornykh, S. M.; Svyazhin, A. D.; Shreder, E. I.; Marchenkov, V. V.; Dyakina, V. P.

    2007-01-01

    We present the results of measurements of low-temperature heat capacity, as well as electrical and magnetic properties of Heusler alloys Fe 2 VAl and Fe 2 CrAl prepared in different ways using various heat treatment regimes. The density of states at the Fermi level is estimated. A contribution of ferromagnetic clusters in the low-temperature heat capacity of the Fe 2 VAl alloy is detected. The change in the number and volume of clusters as a result of annealing of an alloy affects the behavior of their low-temperature heat capacity, resistivity, and magnetic properties

  1. Low-temperature carbonization

    Energy Technology Data Exchange (ETDEWEB)

    Strankmuller, J

    1954-01-01

    The low-temperature carbonization plant at Boehlen in Eastern Germany (the first in which Lurgi type ovens were installed) worked with a throughput of 300 tons of brown-coal briquets per day per oven since 1936, later increased to 365 tons per day. The rising demand for low-temperature tar for hydrogenation purposes led to development of a modified oven of 450 tons throughput. This was achieved by stepping up the flow of the circulating gas and air mixture from 420,000 to 560,000 cubic feet per hour and by additional rows of V-shaped deflectors across the width of the oven chamber, which break up and loosen the charge, thus reducing cooling-gas pressure and allowing a greater flow of scavenging gas. The distance traversed by each briquet is nearly doubled, and the temperature gradient is less. It is claimed that the tar and the coke from modified ovens are of comparable quality. The compressive strength of the briquets was found to have an appreciable effect on the output. Better qts the chemistry, mechanism and thermodynamics of the Fischer-Tropsch reaction and aectromagnetic radiation.

  2. Washing water treatment process for UF_6 cylinder by adjusting evaporation technology in a low temperature and low pressure

    International Nuclear Information System (INIS)

    Kim, Ki-tae; Ju, Young-jong; Cho, Nam-chan; Kim, Yun-kwan; Jin, Chang-suk

    2016-01-01

    The liquid waste is treated in this procedure; 1) Add NaOH to the liquid waste and filter the mixture with a screen. 2) Screened residue is dried and then stored in a uranium storage. 3) liquid part is moved to a storage tank and radioactivity is measured in the liquid. 5) If the concentration of radioactivity is lower than corresponding regulation limit, the liquid moved to a reaction tank and evaporated with additional low concentration HF in 105℃. 6) Radioactivity of distillate is measured and the value is lower than regulation, it is treated with a thermal decomposition process and discharged to the atmosphere in gas state. 7) Solid waste produced in the evaporation step is managed as solid nuclear waste. The treatment procedure mentioned above has disadvantageous points, producing large amount of solid waste as well as, high energy and chemical consumption. In this study, liquid waste from a real scaled cylinder wash process is applied to evaporation system to confirm feasibility of the application of evaporation and, to reduce waste production and energy consumption. Liquid radioactive wastewater from a real scaled UF6 cylinder wash process was applied to evaporation treatment system. Radioactive concentration in gross alpha was removed 99.9% in the evaporation system. And the concentration in distillate was lower than the discharge regulation. Removal of U-235 was 99.9% in the process. And 15 other kinds of radionuclides in the raw wastewater were removed completely. Secondary waste production of the evaporation system is 15g/L

  3. Extremely low temperature properties of epoxy GFRP

    International Nuclear Information System (INIS)

    Kadotani, Kenzo; Nagai, Matao; Aki, Fumitake.

    1983-01-01

    The examination of fiber-reinforced plastics, that is, plastics such as epoxy, polyester and polyimide reinforced with high strength fibers such as glass, carbon, boron and steel, for extremely low temperature use began from the fuel tanks of rockets. Therafter, the trial manufacture of superconducting generators and extremely low temperature transformers and the manufacture of superconducting magnets for nuclear fusion experimental setups became active, and high performance FRPs have been adopted, of which the extremely low temperature properties have been sufficiently grasped. Recently, the cryostats made of FRPs have been developed, fully utilizing such features of FRPs as high strength, high rigidity, non-magnetic material, insulation, low heat conductivity, light weight and the freedom of molding. In this paper, the mechanical properties at extremely low temperature of the plastic composite materials used as insulators and structural materials for extremely low temperature superconducting equipment is outlined, and in particular, glass fiber-reinforced epoxy laminates are described somewhat in detail. The fracture strain of GFRP at extremely low temperature is about 1.3 times as large as that at room temperature, but at extremely low temperature, clear cracking occurred at 40% of the fracture strain. The linear thermal contraction of GFRP showed remarkable anisotropy. (Kako, I.)

  4. Low temperature and short-term high-CO2 treatment in postharvest storage of table grapes at two maturity stages: Effects on transcriptome profiling.

    Directory of Open Access Journals (Sweden)

    Raquel Rosales

    2016-07-01

    Full Text Available Table grapes (Vitis vinifera cv. Cardinal are highly perishable and their quality deteriorates during postharvest storage at low temperature mainly because of sensitivity to fungal decay and senescence of rachis. The application of a 3-day CO2 treatment (20 kPa CO2 + 20 kPa O2 + 60 kPa N2 at 0ºC reduced total decay and retained fruit quality in early and late-harvested table grapes during postharvest storage. In order to study the transcriptional responsiveness of table grapes to low temperature and high CO2 levels in the first stage of storage and how the maturity stage affect these changes, we have performed a comparative large-scale transcriptional analysis using the custom-made GrapeGen GeneChip®. In the first stage of storage, low temperature led to a significantly intense change in grape skin transcriptome irrespective of fruit maturity, although there were different changes within each stage. In the case of CO2 treated samples, in comparison to fruit at time zero, only slight differences were observed. Functional enrichment analysis revealed that major modifications in the transcriptome profile of early- and late-harvested grapes stored at 0ºC are linked to biotic and abiotic stress-responsive terms. However, in both cases there is a specific reprogramming of the transcriptome during the first stage of storage at 0ºC in order to withstand the cold stress. Thus, genes involved in gluconeogenesis, photosynthesis, mRNA translation and lipid transport were up-regulated in the case of early-harvested grapes, and genes related to protein folding stability and intracellular membrane trafficking in late-harvested grapes. The beneficial effect of high CO2 treatment maintaining table grape quality seems to be an active process requiring the induction of several transcription factors and kinases in early-harvested grapes, and the activation of processes associated to the maintenance of energy in late-harvested grapes.

  5. Low Temperature and Short-Term High-CO2 Treatment in Postharvest Storage of Table Grapes at Two Maturity Stages: Effects on Transcriptome Profiling.

    Science.gov (United States)

    Rosales, Raquel; Romero, Irene; Fernandez-Caballero, Carlos; Escribano, M Isabel; Merodio, Carmen; Sanchez-Ballesta, M Teresa

    2016-01-01

    Table grapes (Vitis vinifera cv. Cardinal) are highly perishable and their quality deteriorates during postharvest storage at low temperature mainly because of sensitivity to fungal decay and senescence of rachis. The application of a 3-day CO2 treatment (20 kPa CO2 + 20 kPa O2 + 60 kPa N2) at 0°C reduced total decay and retained fruit quality in early and late-harvested table grapes during postharvest storage. In order to study the transcriptional responsiveness of table grapes to low temperature and high CO2 levels in the first stage of storage and how the maturity stage affect these changes, we have performed a comparative large-scale transcriptional analysis using the custom-made GrapeGen GeneChip®. In the first stage of storage, low temperature led to a significantly intense change in grape skin transcriptome irrespective of fruit maturity, although there were different changes within each stage. In the case of CO2 treated samples, in comparison to fruit at time zero, only slight differences were observed. Functional enrichment analysis revealed that major modifications in the transcriptome profile of early- and late-harvested grapes stored at 0°C are linked to biotic and abiotic stress-responsive terms. However, in both cases there is a specific reprogramming of the transcriptome during the first stage of storage at 0°C in order to withstand the cold stress. Thus, genes involved in gluconeogenesis, photosynthesis, mRNA translation and lipid transport were up-regulated in the case of early-harvested grapes, and genes related to protein folding stability and intracellular membrane trafficking in late-harvested grapes. The beneficial effect of high CO2 treatment maintaining table grape quality seems to be an active process requiring the induction of several transcription factors and kinases in early-harvested grapes, and the activation of processes associated to the maintenance of energy in late-harvested grapes.

  6. Effect of ultrasound, low-temperature thermal and alkali pre-treatments on waste activated sludge rheology, hygienization and methane potential.

    Science.gov (United States)

    Ruiz-Hernando, M; Martín-Díaz, J; Labanda, J; Mata-Alvarez, J; Llorens, J; Lucena, F; Astals, S

    2014-09-15

    Waste activated sludge is slower to biodegrade under anaerobic conditions than is primary sludge due to the glycan strands present in microbial cell walls. The use of pre-treatments may help to disrupt cell membranes and improve waste activated sludge biodegradability. In the present study, the effect of ultrasound, low-temperature thermal and alkali pre-treatments on the rheology, hygienization and biodegradability of waste activated sludge was evaluated. The optimum condition of each pre-treatment was selected based on rheological criteria (reduction of steady state viscosity) and hygienization levels (reduction of Escherichia coli, somatic coliphages and spores of sulfite-reducing clostridia). The three pre-treatments were able to reduce the viscosity of the sludge, and this reduction was greater with increasing treatment intensity. However, only the alkali and thermal conditioning allowed the hygienization of the sludge, whereas the ultrasonication did not exhibit any notorious effect on microbial indicators populations. The selected optimum conditions were as follows: 27,000 kJ/kg TS for the ultrasound, 80 °C during 15 min for the thermal and 157 g NaOH/kg TS for the alkali. Afterward, the specific methane production was evaluated through biomethane potential tests at the specified optimum conditions. The alkali pre-treatment exhibited the greatest methane production increase (34%) followed by the ultrasonication (13%), whereas the thermal pre-treatment presented a methane potential similar to the untreated sludge. Finally, an assessment of the different treatment scenarios was conducted considering the results together with an energy balance, which revealed that the ultrasound and alkali treatments entailed higher costs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Low Temperature Plasma Medicine

    Science.gov (United States)

    Graves, David

    2013-10-01

    Ionized gas plasmas near room temperature are used in a remarkable number of technological applications mainly because they are extraordinarily efficient at exploiting electrical power for useful chemical and material transformations near room temperature. In this tutorial address, I will focus on the newest area of low temperature ionized gas plasmas (LTP), in this case operating under atmospheric pressure conditions, in which the temperature-sensitive material is living tissue. LTP research directed towards biomedical applications such as sterilization, surgery, wound healing and anti-cancer therapy has seen remarkable growth in the last 3-5 years, but the mechanisms responsible for the biomedical effects have remained mysterious. It is known that LTP readily create reactive oxygen species (ROS) and reactive nitrogen species (RNS). ROS and RNS (or RONS), in addition to a suite of other radical and non-radical reactive species, are essential actors in an important sub-field of aerobic biology termed ``redox'' (or oxidation-reduction) biology. I will review the evidence suggesting that RONS generated by plasmas are responsible for their observed therapeutic effects. Other possible bio-active mechanisms include electric fields, charges and photons. It is common in LTP applications that synergies between different mechanisms can play a role and I will review the evidence for synergies in plasma biomedicine. Finally, I will address the challenges and opportunities for plasma physicists to enter this novel, multidisciplinary field.

  8. Low-Temperature Supercapacitors

    Science.gov (United States)

    Brandon, Erik J.; West, William C.; Smart, Marshall C.

    2008-01-01

    An effort to extend the low-temperature operational limit of supercapacitors is currently underway. At present, commercially available non-aqueous supercapacitors are rated for a minimum operating temperature of -40 C. A capability to operate at lower temperatures would be desirable for delivering power to systems that must operate in outer space or in the Polar Regions on Earth. Supercapacitors (also known as double-layer or electrochemical capacitors) offer a high power density (>1,000 W/kg) and moderate energy density (about 5 to 10 Wh/kg) technology for storing energy and delivering power. This combination of properties enables delivery of large currents for pulsed applications, or alternatively, smaller currents for low duty cycle applications. The mechanism of storage of electric charge in a supercapacitor -- at the electrical double-layer formed at a solid-electrode/liquid-electrolyte interface -- differs from that of a primary or secondary electrochemical cell (i.e., a battery) in such a manner as to impart a long cycle life (typically >10(exp 6) charge/discharge cycles).

  9. Self-Passivation by Fluorine Plasma Treatment and Low-Temperature Annealing in SiGe Nano wires for Biochemical Sensors

    International Nuclear Information System (INIS)

    Chang, K.; Chen, C.; Kuo, P.; Chen, Y.; Chang, T.; Lai, C.; Whang, A. J.; Lai, Y.; Chen, H.; Hsieh, I.

    2014-01-01

    Nano wires are widely used as highly sensitive sensors for electrical detection of biological and chemical species. Modifying the band structure of strained-Si metal-oxide-semiconductor field-effect transistors by applying the in-plane tensile strain reportedly improves electron and hole mobility. The oxidation-induced Ge condensation increases the Ge fraction in a SiGe-on-insulator (SGOI) and substantially increases hole mobility. However, oxidation increases the number of surface states, resulting in hole mobility degradation. In this work, 3-aminopropyltrimethoxysilane (APTMS) was used as a biochemical reagent. The hydroxyl molecule on the oxide surface was replaced by the methoxy groups of the APTMS molecule. We proposed a surface plasma treatment to improve the electrical properties of SiGe nano wires. Fluorine plasma treatment can result in enhanced rates of thermal oxidation and speed up the formation of a self-passivation oxide layer. Like a capping oxide layer, the self-passivation oxide layer reduces the rate of follow-up oxidation. Pre oxidation treatment also improved the sensitivity of SiGe nano wires because the Si-F binding was held at a more stable interface state compared to bare nano wire on the SiGe surface. Additionally, the sensitivity can be further improved by either the N 2 plasma posttreatment or the low-temperature post annealing due to the suppression of out diffusion of Ge and F atoms from the SiGe nano wire surface.

  10. Improvement in surface hydrophilicity and resistance to deformation of natural leather through O{sub 2}/H{sub 2}O low-temperature plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    You, Xuewei; Gou, Li, E-mail: gouli@scu.edu.cn; Tong, Xingye

    2016-01-01

    Graphical abstract: - Highlights: • O{sub 2}/H{sub 2}O can increase oxygen concentration in the plasma compared to the pure O{sub 2} atmosphere. • Pores at the surface of natural leather became larger and deeper with enhanced permeability of water. • The initial water contact angle was about 21°. • Its preferable surface hydrophilicity kept for 3 days, which gives guidance for next process. • The elongation of the treated sample for 10 min was twice as large as that of the untreated sample. - Abstract: The natural leather was modified through O{sub 2}/H{sub 2}O low-temperature plasma treatment. Surface morphology was characterized by scanning electron microscopy (SEM) and the results showed that the pores on the leather surface became deeper and larger with enhanced permeability of water and vapor. XPS and FTIR-ATR was performed to determine the chemical composition of natural leather surface. Oxygen-containing groups were successfully grafted onto the surface of natural leather and oxygen content increased with longer treatment time. After O{sub 2}/H{sub 2}O plasma treatment, initial water contact angle was about 21° and water contact angles were not beyond 55° after being stored for 3 days. Furthermore, the tensile test indicated that the resistance to deformation had a prominent transform without sacrificing the tensile strength.

  11. Improvement in surface hydrophilicity and resistance to deformation of natural leather through O_2/H_2O low-temperature plasma treatment

    International Nuclear Information System (INIS)

    You, Xuewei; Gou, Li; Tong, Xingye

    2016-01-01

    Graphical abstract: - Highlights: • O_2/H_2O can increase oxygen concentration in the plasma compared to the pure O_2 atmosphere. • Pores at the surface of natural leather became larger and deeper with enhanced permeability of water. • The initial water contact angle was about 21°. • Its preferable surface hydrophilicity kept for 3 days, which gives guidance for next process. • The elongation of the treated sample for 10 min was twice as large as that of the untreated sample. - Abstract: The natural leather was modified through O_2/H_2O low-temperature plasma treatment. Surface morphology was characterized by scanning electron microscopy (SEM) and the results showed that the pores on the leather surface became deeper and larger with enhanced permeability of water and vapor. XPS and FTIR-ATR was performed to determine the chemical composition of natural leather surface. Oxygen-containing groups were successfully grafted onto the surface of natural leather and oxygen content increased with longer treatment time. After O_2/H_2O plasma treatment, initial water contact angle was about 21° and water contact angles were not beyond 55° after being stored for 3 days. Furthermore, the tensile test indicated that the resistance to deformation had a prominent transform without sacrificing the tensile strength.

  12. Low-temperature calorimetry

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    Heat capacity, standard entropy, standard enthalpy, and standard Gibbs energy of 242 PuF 4 from 10 to 350 0 K, of 244 PuO 2 from 4 to 25 0 K, of Li 3 N from 5 to 350 0 K, and of Cs 2 UO 4 from 5 to 350 0 K are reported. (U.S.)

  13. Irradiation in combination of heat treatment of mango puree

    International Nuclear Information System (INIS)

    Noomhorm, A.; Apintanapong, M.

    1996-01-01

    The effect of irradiation with heat combination treatment on the shelf life and quality of mango puree was studied. Thermal inactivation of polyphenol oxidase enzyme at 80 degree C and 15 min. was used as a measure of adequacy of pre-heat treatment. Irradiation of mango puree after heat treatment at dosage of 0, 2, 4, 6 and 8 kGy showed no change in mc, pH, acidity, and TSS but during storage, growth of microorganisms brought changes in these values. Irradiation in combination with low temperature (5 degree C) reduced discoloration and darkening rate during storage. Irradiation dose from 0 to 8 kGy resulted in log linear reductions in microorganism levels but at 6 and 8 kGy, there was no growth of microorganisms. Products irradiated at 8 kGy showed no microorganism growth at both temperatures

  14. Sorption heat storage for long-term low-temperature applications: A review on the advancements at material and prototype scale

    NARCIS (Netherlands)

    Scapino, L.; Zondag, H.A.; Van Bael, J.; Diriken, J.; Rindt, C.C.M.

    2017-01-01

    Sorption heat storage has the potential to store large amounts of thermal energy from renewables and other distributed energy sources. This article provides an overview on the recent advancements on long-term sorption heat storage at material- and prototype- scales. The focus is on applications

  15. Low-temperature specific heat of single-crystal Bi2CaSr2Cu2O8 and Tl2Ca2Ba2Cu3O10

    Science.gov (United States)

    Urbach, J. S.; Mitzi, D. B.; Kapitulnik, A.; Wei, J. Y. T.; Morris, D. E.

    1989-06-01

    We report specific-heat measurements from 2 to 15 K on single crystals of Bi2CaSr2Cu2O8 and Tl2Ca2Ba2Cu3O10 We find low-temperature deviations from the Debye law that can be attributed to spin-glass behavior of a small concentration of isolated impurity copper moments. At higher temperatures, we observe contributions to the specific heat that can be attributed to a soft-phonon mode, possibly associated with the superstructure in the Bi-O and Tl-O layers. From our single-crystal data, we conclude that the thallium- and bismuth-based copper oxide superconductors show no measurable linear term in the specific heat [γ(0)<=1 mJ/mole K2].

  16. Low-temperature specific heat of single-crystal Bi2CaSr2Cu2O8 and Tl2Ca2Ba2Cu3O10

    International Nuclear Information System (INIS)

    Urbach, J.S.; Mitzi, D.B.; Kapitulnik, A.; Wei, J.Y.T.; Morris, D.E.; Physics Division, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720)

    1989-01-01

    We report specific-heat measurements from 2 to 15 K on single crystals of Bi 2 CaSr 2 Cu 2 O 8 and Tl 2 Ca 2 Ba 2 Cu 3 O 10 We find low-temperature deviations from the Debye law that can be attributed to spin-glass behavior of a small concentration of isolated impurity copper moments. At higher temperatures, we observe contributions to the specific heat that can be attributed to a soft-phonon mode, possibly associated with the superstructure in the Bi-O and Tl-O layers. From our single-crystal data, we conclude that the thallium- and bismuth-based copper oxide superconductors show no measurable linear term in the specific heat [γ(0) less than or equal to 1 mJ/mole K 2

  17. Magnetic susceptibility and specific heat of the one-dimensional conductor (H3O) sub (1,6) Pt (C2O4)2.nH2O at low temperatures

    International Nuclear Information System (INIS)

    Raede, H.S.

    1985-01-01

    It has been shown recently that some transition metal complexes exhibit one-dimensional metallic properties. It is reported, in this context, susceptibility and specific heat measurements of polycrystalline (H 3 O) 1 , 6 Pt(C 2 O 4 ) 2 .nH 2 O in the low temperature range. It is found that the susceptibility can be described by a non-uniform Curie law with a characteristic break in the slope. The specific heat reveals no linear temperature contribution, which could be explained by a transition into a Peierls distorted state. Until 13 0 K, the heat capacity follows a T 3 -law. Deviations at higher temperatures are possibly attributed to the anisotropy of the system [pt

  18. Plasma assisted heat treatment: annealing

    International Nuclear Information System (INIS)

    Brunatto, S F; Guimaraes, N V

    2009-01-01

    This work comprises a new dc plasma application in the metallurgical-mechanical field, called plasma assisted heat treatment, and it presents the first results for annealing. Annealing treatments were performed in 90% reduction cold-rolled niobium samples at 900 deg. C and 60 min, in two different heating ways: (a) in a hollow cathode discharge (HCD) configuration and (b) in a plasma oven configuration. The evolution of the samples' recrystallization was determined by means of the microstructure, microhardness and softening rate characterization. The results indicate that plasma species (ions and neutrals) bombardment in HCD plays an important role in the recrystallization process activation and could lead to technological and economical advantages considering the metallic materials' heat treatment application. (fast track communication)

  19. Iron in the Fire: Searching for Fire's Magnetic Fingerprint using Controlled Heating Experiments, High-Resolution FORCs, IRM Coercivity Spectra, and Low-Temperature Remanence Experiments

    Science.gov (United States)

    Lippert, P. C.; Reiners, P. W.

    2014-12-01

    Evidence for recent climate-wildfire linkages underscores the need for better understanding of relationships between wildfire and major climate shifts in Earth history, which in turn offers the potential for prognoses for wildfire and human adaptations to it. In particular, what are the links between seasonality and wildfire frequency and severity, and what are the feedbacks between wildfire, landscape evolution, and biogeochemical cycles, particularly the carbon and iron cycles? A key first step in addressing these questions is recovering well-described wildfire records from a variety of paleolandscapes and paleoclimate regimes. Although charcoal and organic biomarkers are commonly used indicators of fire, taphonomic processes and time-consuming analytical preparations often preclude their routine use in some environments and in high-stratigraphic resolution paleowildfire surveying. The phenomenological relationship between fire and magnetic susceptibility can make it a useful surveying tool, but increased magnetic susceptibility in sediments is not unique to fire, and thus limits its diagnostic power. Here we utilize component-specific rock magnetic methods and analytical techniques to identify the rock magnetic fingerprint of wildfire. We use a custom-designed air furnace, a series of iron-free laboratory soils, natural saprolites and soils, and fuels from Arizona Ponderosa pine forests and grasslands to simulate wildfire in a controlled and monitored environment. Soil-ash residues and soil and fuel controls were then characterized using First Order Reversal Curve (FORC) patterns, DC backfield IRM coercivity spectra, low-temperature SIRM demagnetization behavior, and low-temperature cycling of room-temperature SIRM behavior. We will complement these magnetic analyses with high-resolution TEM of magnetic extracts. Here we summarize the systematic changes to sediment magnetism as pyrolitized organic matter is incorporated into artificial and natural soils. These

  20. Numerical modelling and experimental measurements for a low-temperature district heating substation for instantaneous preparation of DHW with respect to service pipes

    DEFF Research Database (Denmark)

    Brand, Marek; Thorsen, Jan Eric; Svendsen, Svend

    2012-01-01

    Traditional district heating (DH) systems are becoming uneconomic as the number of new and renovated buildings with reduced heating requirements increases. To keep DH competitive in the future, heat losses in DH networks need to be reduced. One option is to reduce the supply temperature of DH...... as much as possible. This requires a review and improvement of a DH network, in-house substations, and the whole domestic hot water (DHW) supply system, with the focus on user comfort, hygiene, overall cost and energy efficiency. This paper describes some practical approaches to the implementation of low...... concept as well for individual components. The results show that the way that the service pipe is operated has a significant effect on waiting time for DHW, heat loss, and overall cost. Furthermore, the service pipe should be kept warm by using a bypass in order to fulfil the comfort requirements for DHW...

  1. Low temperature distillation

    Energy Technology Data Exchange (ETDEWEB)

    1937-07-21

    To distil mineral or organic material, the material is heated by means of a hot gas entering into contact with and traversing the material in a horizontal direction. The vertical retort is charged with material from the hopper and hot gases from the furnace after traversing the boiler enter the preheating zone, pass through the slots and charge therein and are educted through connection by the blower. The charge passes downwardly to the distillation zone wherein hot gases from the heater are passed via pipe and slots through the chambers and to the pipe controlled by the dampers. These gases are recycled by the fan through the heater and chamber, that portion of the gases corresponding to the amount of vapours evolved from the distillation being evacuated via the pipe to the condensing plant not shown. Steam and/or a limited quantity of water may be admitted to the distillation zone.

  2. Basics of Low-temperature Refrigeration

    CERN Document Server

    Alekseev, A.

    2014-07-17

    This chapter gives an overview of the principles of low temperature refrigeration and the thermodynamics behind it. Basic cryogenic processes - Joule-Thomoson process, Brayton process as well as Claude process - are described and compared. A typical helium laboratory refrigerator based on Claude process is used as a typical example of a low-temperature refrigeration system. A description of the hardware components for helium liquefaction is an important part of this paper, because the design of the main hardware components (compressors, turbines, heat exchangers, pumps, adsorbers, etc.) provides the input for cost calculation, as well as enables to estimate the reliability of the plant and the maintenance expenses. All these numbers are necessary to calculate the economics of a low temperature application.

  3. Basics of Low-temperature Refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Alekseev, A [Linde AG, Munich (Germany)

    2014-07-01

    This chapter gives an overview of the principles of low temperature refrigeration and the thermodynamics behind it. Basic cryogenic processes - Joule-Thomoson process, Brayton process as well as Claude process - are described and compared. A typical helium laboratory refrigerator based on Claude process is used as a typical example of a low-temperature refrigeration system. A description of the hardware components for helium liquefaction is an important part of this paper, because the design of the main hardware components (compressors, turbines, heat exchangers, pumps, adsorbers, etc.) provides the input for cost calculation, as well as enables to estimate the reliability of the plant and the maintenance expenses. All these numbers are necessary to calculate the economics of a low temperature application.

  4. Effect of the rate of heating on the quality of the primary tar in low-temperature coal-carbonization process

    Energy Technology Data Exchange (ETDEWEB)

    Turskii, Y I

    1956-01-01

    Two stages are observed. The first stage yields products of the primary and partial decomposition of coal, mainly water, CO/sub 2/, and CO as decomposition products of functional groups (-COOH, > CO, - OH, and so forth). No tar is formed in this stage. The structural decomposition and tar formation occur in the second stage. The rate of heating is important for the quality of the tar obtained. The slow rate of heating with both stages following each other yields a good-quality tar, richer in C and H, with lower O content. In case of high rate of heating both stages overlap. The tar is of poorer quality with higher specific gravity, and contains more O and asphaltenes. The complete experimental data are given in detail.

  5. Experimental investigation of a low-temperature organic Rankine cycle (ORC) engine under variable heat input operating at both subcritical and supercritical conditions

    International Nuclear Information System (INIS)

    Kosmadakis, George; Manolakos, Dimitris; Papadakis, George

    2016-01-01

    Highlights: • Small-scale ORC engine with converted scroll expander is installed at laboratory. • Design suitable for supercritical operation. • ORC engine tested at temperature equal to 95 °C. • Focus is given on expansion and thermal efficiency. • Supercritical operation showed some promising performance. - Abstract: The detailed experimental investigation of an organic Rankine cycle (ORC) is presented, which is designed to operate at supercritical conditions. The net capacity of this engine is almost 3 kW and the laboratory testing of the engine includes the variation of the heat input and of the hot water temperature. The maximum heat input is 48 kW_t_h, while the hot water temperature ranges from 65 up to 100°C. The tests are conducted at the laboratory and the heat source is a controllable electric heater, which can keep the hot water temperature constant, by switching on/off its electrical resistances. The expansion machine is a modified scroll compressor with major conversions, in order to be able to operate with safety at high pressure (or even supercritical at some conditions). The ORC engine is equipped with a dedicated heat exchanger of helical coil design, suitable for such applications. The speeds of the expander and ORC pump are regulated with frequency inverters, in order to control the cycle top pressure and heat input. The performance of all components is evaluated, while special attention is given on the supercritical heat exchanger and the scroll expander. The performance tests examined here concern the variation of the heat input, while the hot water temperature is equal to 95 °C. The aim is to examine the engine performance at the design conditions, as well as at off-design ones. Especially the latter ones are very important, since this engine will be coupled with solar collectors at the final configuration, where the available heat is varied to a great extent. The engine has been measured at the laboratory, where a thermal

  6. Regularities of texture formation in alloys undergoing phase transformations during heat treatment and plastic working

    International Nuclear Information System (INIS)

    Ageev, N.V.; Babarehko, A.A.

    1983-01-01

    Peculiarities of texture formation in metals undergoing phase transformations in the temperature range of heat treatment and hot working are investigated theoretically and experimentally. A low-temperature phase after hot working is shown to inherite a high-temperature phase texture due to definite orientation conformity during phase transformation. Strengthened heat and thermomechanical treatments, as a rule, do not destroy material texture but change it

  7. Low temperature heat capacity measurements of the spin-liquid states of hydrogenated and deuterated κ-(BEDT-TTF)2Cu2(CN)3

    International Nuclear Information System (INIS)

    Yamashita, S.; Yamamoto, T.; Nakazawa, Y.

    2010-01-01

    Heat capacity measurements of organic triangular lattice compound κ-(BEDT-TTF) 2 Cu 2 (CN) 3 were performed to discuss the low energy excitations from the spin-liquid ground states. Existence of the T-linear electronic coefficient with finite electronic heat capacity coefficient γ was confirmed in three different samples from different batches, although small sample dependence was observed in the absolute values of the heat capacities. Concerning the sample in which hydrogen atoms in ethylene group in BEDT-TTF molecule have been substituted by deuterons, we have observed almost similar thermodynamic behavior as the hydrogenated sample. The absence of drastic change of electronic properties of this compound is consistent with the electronic phase diagram given by Kurosaki et al. [11] (Phys. Rev. Lett. 95 (2005) 17001). The obtained data are well consistent with the previous heat capacity experiments. The existence of the γ term demonstrates that the excitations from the quantum spin-liquid states show a gapless behavior at least down to 0.7 K.

  8. Heavy mediums and materials (physics of the condensed state). Study of disordered systems at low temperature. Specific heat measurement in neutron irradiated quartz

    International Nuclear Information System (INIS)

    De Sa, L.

    1987-09-01

    Specific heat of neutron irradiated silicas presents characteristics evolving with radiation dose and is a good way to study properties of disordered systems. Results obtained and comparison with other experiments allow to follow amorphization and defects created by irradiation and raise hypothesis about the evolution of microscopic structure of these materials [fr

  9. Solution-phase synthesis of nanomaterials at low temperature

    Science.gov (United States)

    Zhu, Yongchun; Qian, Yitai

    2009-01-01

    This paper reviews the solution-phase synthesis of nanoparticles via some routes at low temperatures, such as room temperature route, wave-assisted synthesis (γ-irradiation route and sonochemical route), directly heating at low temperatures, and hydrothermal/solvothermal methods. A number of strategies were developed to control the shape, the size, as well as the dispersion of nanostructures. Using diethylamine or n-butylamine as solvent, semiconductor nanorods were yielded. By the hydrothermal treatment of amorphous colloids, Bi2S3 nanorods and Se nanowires were obtained. CdS nanowires were prepared in the presence of polyacrylamide. ZnS nanowires were obtained using liquid crystal. The polymer poly (vinyl acetate) tubule acted as both nanoreactor and template for the CdSe nanowire growth. Assisted by the surfactant of sodium dodecyl benzenesulfonate (SDBS), nickel nanobelts were synthesized. In addition, Ag nanowires, Te nanotubes and ZnO nanorod arrays could be prepared without adding any additives or templates.

  10. Characteristic of Low Temperature Carburized Austenitic Stainless Steel

    Science.gov (United States)

    Istiroyah; Pamungkas, M. A.; Saroja, G.; Ghufron, M.; Juwono, A. M.

    2018-01-01

    Low temperature carburizing process has been carried out on austenitic stainless steel (ASS) type AISI 316L, that contain chromium in above 12 at%. Therefore, conventional heat treatment processes that are usually carried out at high temperatures are not applicable. The sensitization process due to chromium migration from the grain boundary will lead to stress corrosion crack and decrease the corrosion resistance of the steel. In this study, the carburizing process was carried out at low temperatures below 500 °C. Surface morphology and mechanical properties of carburized specimens were investigated using optical microscopy, non destructive profilometer, and Vicker microhardness. The surface roughness analysis show the carburising process improves the roughness of ASS surface. This improvement is due to the adsorption of carbon atoms on the surface of the specimen. Likewise, the hardness test results indicate the carburising process increases the hardness of ASS.

  11. Relationship between meat toughness and properties of connective tissue from cows and young bulls heat treated at low temperatures for prolonged times

    DEFF Research Database (Denmark)

    Christensen, Line; Ertbjerg, Per; Løje, Hanne

    2013-01-01

    of beef was investigated and the relationship to properties of connective tissue was examined. Measurements of toughness, collagen solubility, cathepsin activity and protein denaturation of beef semitendinosus heated at temperatures between 53. °C and 63. °C for up to 19 1/2. h were conducted. The results...... of the connective tissue, caused partly by denaturation or conformational changes of the proteins and/or by solubilization of collagen. © 2012 Elsevier Ltd....

  12. Improvements relating to the low temperature carbonisation of coal, shale, and other suitable fuels

    Energy Technology Data Exchange (ETDEWEB)

    Hackford, J E

    1930-03-10

    In the low-temperature carbonization of coal, shale, and other suitable fuel is interposed between the fuel to be carbonized and the container, conveyor, grate, or other surface or surfaces with which the fuel normally contacts during the heat treatment. A medium decomposes during the said heat treatment, to produce a dry carbon at the surface or surfaces contacted without passing through an intermediate plastic or liquid phase during decomposition.

  13. Power by waste heat recovery from low temperature industrial flue gas by Organic Flash Cycle (OFC) and transcritical-CO_2 power cycle: A comparative study through combined thermodynamic and economic analysis

    International Nuclear Information System (INIS)

    Mondal, Subha; De, Sudipta

    2017-01-01

    Both Organic flash cycle and transcritical CO_2 power cycle (T-CO_2 power cycle) allow cooling of hot flue gas stream to an appreciably lower temperature due to the absence of pinch limitation. In the present study, a combined thermodynamic and economic comparison is conducted between a T-CO_2 power cycle and Organic flash cycles using R-245fa and R600 as the working fluids. It is observed that work output per kg of flue gas flow rate is slightly higher for the T-CO_2 power cycle if the flue gas is allowed to cool to the corresponding lowest possible temperature in the Heat Recovery Unit (HRU). It is also observed that with maximum possible cooling of flue gas, minimum bare module costs (BMCs) for each kW power output of OFCs are somewhat higher compared to that of T-CO_2 power cycle. Minimum BMCs for each kW output of OFCs can be reduced substantially by increasing terminal temperature difference at the low temperature end of the HRU. However, the increasing terminal temperature difference at the low temperature end of the HRU is having negligible effect on BMC ($/kW) of T-CO_2 power cycle. - Highlights: • Combined thermodynamic and economic analysis done for T-CO_2 power cycle and OFC. • With highest heat recovery, T-CO_2 cycle produces slightly higher work output/kg of flue gas. • With highest heat recovery, minimum bare module costs in $/kW is slightly higher for OFCs. • Work outputs/kg of flue gas of all cycles are almost equal for these minimum BMCs. • BMCs in $/kW for OFCs sharply decrease with larger flue gas exit temperature.

  14. Vibrational collapse of boroxol rings in compacted B2O3 glasses: a study of Raman scattering and low temperature specific heat

    Science.gov (United States)

    Carini, Giovanni, Jr.; Carini, Giuseppe; D’Angelo, Giovanna; Federico, Mauro; Romano, Valentino

    2018-05-01

    Low and high frequency Raman scattering of B2O3 glasses, compacted under GPa pressures, has been performed to investigate structural changes due to increasing atomic packing. Compacted glasses, annealed at ambient temperature and pressure, experience a time-dependent decrease of the density to a smaller constant value over a period of few months, displaying a permanent plastic deformation. Increasing densification determines a parallel and progressive decrease of the intensity of the Boson peak and the main band at 808 cm‑1, both these modes arising from localized vibrations involving planar boroxol rings (B3O6), the glassy units formed from three basic BO3 triangles. The 808 cm‑1 mode preserves its frequency, while the BP evidences a well-defined frequency increase. The high-frequency multicomponent band between 1200 and 1600 cm‑1 also changes with increasing densification, disclosing a decreasing intensity of the 1260 cm‑1 mode due to oxygen vibrations of BO3 units bridging boroxol rings. This indicates the gradual vibrational collapse of groups formed from rings connected by more complex links than a single bridging oxygen. The observed behaviours suggest that glass compaction causes severe deformation of boroxol rings, determining a decrease of groups which preserve unaltered their vibrational activity. Growing glass densification stiffens the network and leads to a decrease of the excess heat capacity over the Debye prediction below 20 K, which is not accounted for by the hardening of the elastic continuum. By using the low-frequency Raman scattering to determine the temperature dependence of the heat capacity, it has been evaluated the density of low-frequency vibrational states which discloses a significant reduction of excess modes with increasing density.

  15. Thermodynamic power stations at low temperatures

    Science.gov (United States)

    Malherbe, J.; Ployart, R.; Alleau, T.; Bandelier, P.; Lauro, F.

    The development of low-temperature thermodynamic power stations using solar energy is considered, with special attention given to the choice of the thermodynamic cycle (Rankine), working fluids (frigorific halogen compounds), and heat exchangers. Thermomechanical conversion machines, such as ac motors and rotating volumetric motors are discussed. A system is recommended for the use of solar energy for irrigation and pumping in remote areas. Other applications include the production of cold of fresh water from brackish waters, and energy recovery from hot springs.

  16. CO2-reductions in low energy buildings and communities by implementation of low temperature district heating systems. Demonstration cases in Boligforeningen Ringgaarden and EnergyFlexHouse. Main report

    Energy Technology Data Exchange (ETDEWEB)

    Worm, J.

    2011-05-15

    The project consisted of 3 tasks. In task 1, the aim was, through demonstration in EnergyFlexHouse in Taastrup, to analyse the district heating tank in interaction with a larger low-energy house, and to analyse different patterns of hot water use in order to validate and further develop the concept of low temperature district heating (LTDH). In task 2, the aim was, through demonstration in the housing community Ringgaarden in Lystrup near Aarhus, to show that the low heat losses found in a previous project can be achieved in practice, and to further develop the technology of the concept. In task 3, the aim was to assess the potential for CO{sub 2} reductions and energy conservation in both new and existing district heating distribution systems using the concept of LTDH. Furthermore the aim was to analyse the implementation of LTDH in existing buildings and to analyse optimization of LTDH design. The present report is a summary of the results of the three tasks. Detailed results of each task are presented in three separate reports. (ln)

  17. The Nd-Mn exchange interaction, low temperature specific heat and magnetism of Nd{sub 2/3}Ca{sub 1/3}MnO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Beznosov, Anatoly [B. Verkin Institute for Low Temperature Physics and Engineering NASU, 47 Lenin Avenue, Kharkov 61103 (Ukraine); Fertman, Elena, E-mail: fertman@ilt.kharkov.ua [B. Verkin Institute for Low Temperature Physics and Engineering NASU, 47 Lenin Avenue, Kharkov 61103 (Ukraine); Desnenko, Vladimir [B. Verkin Institute for Low Temperature Physics and Engineering NASU, 47 Lenin Avenue, Kharkov 61103 (Ukraine); Kajnakova, Marcela; Feher, Alexander [Centre of Low Temperature Physics of the Faculty of Science UPJS and IEP SAS, Park Angelinum 9, 04154 Kosice (Slovakia)

    2011-10-15

    The low temperature specific heat and magnetic characteristics of Nd{sub 2/3}Ca{sub 1/3}MnO{sub 3} perovskite are studied in a wide range of magnetic fields (up to 9 T). Temperature dependent specific heat data show a broadened Schottky-like anomaly below 20 K caused by splitting of the Nd{sup 3+} ions ground-state doublet in the effective molecular field H{sub ex}, determined by exchange interaction between Nd and Mn spin systems supplemented by an applied external magnetic field. Existence of the splitting at zero magnetic field and expressed field dependence is the evidence of a strong exchange coupling between Nd and Mn magnetic subsystems. The Nd-ions magnetic ordering leads to an additional contribution to the magnetic moment of the system below 30 K, producing anomalies of the magnetic loss and field-cooled and zero-field-cooled magnetizations. The observed broadened Schottky-like anomalies are fitted for each applied magnetic field by the sum of three Schottky functions. Applied magnetic field extends the anomaly region and shifts it to higher temperatures. Splitting of the higher crystal field Kramers doublets gives an additional contribution to the heat capacity in magnetic fields. The ground state doublet g-factors g{sub ||} and g{sub perpendicular} were estimated to be 3.4 and 2.2, respectively, and H{sub ex} was estimated to be 9 T. The Nd{sup 3+} ions magnetic moment estimated from the magnetization data agrees with the value obtained from the specific heat data. - Highlights: > Low temperature specific heat of Nd{sub 2/3}Ca{sub 1/3}MnO{sub 3} has been measured in magnetic fields up to 9 T. > Schottky-like anomalies are fitted for each magnetic field by a sum of three Schottky functions. > An effective magnetic field of the Mn spin system on Nd ion has been estimated as H{sub ex}=9 T. > Nd{sup 3+} ground-state g-factors have been estimated as g{sub ||}=3.4 and g{sub perpendicular} =2.2. > Magnetic ordering of the Nd subsystem has been revealed below

  18. 29 CFR 1919.80 - Heat treatment.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Heat treatment. 1919.80 Section 1919.80 Labor Regulations...) GEAR CERTIFICATION Certification of Shore-Based Material Handling Devices § 1919.80 Heat treatment. (a) Wherever heat treatment of any loose gear is recommended by the manufacturer, it shall be carried out in...

  19. 29 CFR 1919.36 - Heat treatment.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Heat treatment. 1919.36 Section 1919.36 Labor Regulations...) GEAR CERTIFICATION Certification of Vessels: Tests and Proof Loads; Heat Treatment; Competent Persons § 1919.36 Heat treatment. (a) The annealing of wrought iron gear required by this part shall be...

  20. Effect of low-temperature long-time and high-temperature short-time blanching and frying treatments on the French fry quality of six Irish potato cultivars

    OpenAIRE

    Ngobese, Nomali Ziphorah; Workneh, Tilahun Seyoum; Siwela, Muthulisi

    2017-01-01

    Processing conditions are an important determinant of French fry quality. However, the effect of low-temperature long-time (LTLT) and high-temperature short-time (HTST) blanching and frying treatments has not been investigated in many cultivars. The current study investigates the effect of the sequential application of these treatments on French fries processed from six Irish potato cultivars (Fianna, Innovator, Mondial, Navigator, Panamera and Savanna). Blanching was effected at 75 °C for 10...

  1. Low temperature distillation of coal, shale, etc

    Energy Technology Data Exchange (ETDEWEB)

    1938-08-12

    A process is disclosed for the low temperature distillation of solid carbonaceous fuels, such as coal, lignite, shale or the like, which comprises feeding or supplying the comminuted fuel in the form of a layer of shallow depth to drying and distilling zones in succession moving the fuel forward through the zones, submitting it to progressively increasing nonuniform heating therein by combustion gases supplied to the distillation zone and traveling thence to the drying zone, the gases heating the distillation zone indirectly and the drying zone both indirectly and then directly such that the fuel retains its solid discrete form during substantially the whole of its travel through the drying and distillation zones, subjecting the fuel for a portion of its travel to a zigzag ploughing and propelling movement on a heated sole, and increasing the heating so as to cause fusion of the fuel immediately prior to its discharge from the distillation zone.

  2. Technological uses of low temperature plasmas

    International Nuclear Information System (INIS)

    Lawton, J.

    1975-01-01

    Types of low temperature plasma sources considered include; arc discharge, high pressure discharge, low pressure discharge and flame. The problems of uniform heating of a gas are discussed and it is considered that the most reliable technique is the magnetically rotated arc, but expanded discharges of one kind or another are likely to be serious competitors in the future. The uses of low temperature plasma in chemistry and combustion are considered. The potential for plasma chemistry lies with processes in which the reactions occur in the plasma itself or its neighbouring gas phase, including those which require the vaporization of liquefaction of a refractory material and also highly endothermic reactions. The production of thixotropic silica and acetylene are discussed as examples of such reactions. The field of plasma and combustion including; ignition, flame ionization and soot formation, and the MHD generator, is considered. (U.K.)

  3. Low-temperature thermal expansion

    International Nuclear Information System (INIS)

    Collings, E.W.

    1986-01-01

    This chapter discusses the thermal expansion of insulators and metals. Harmonicity and anharmonicity in thermal expansion are examined. The electronic, magnetic, an other contributions to low temperature thermal expansion are analyzed. The thermodynamics of the Debye isotropic continuum, the lattice-dynamical approach, and the thermal expansion of metals are discussed. Relative linear expansion at low temperatures is reviewed and further calculations of the electronic thermal expansion coefficient are given. Thermal expansions are given for Cu, Al and Ti. Phenomenologic thermodynamic relationships are also discussed

  4. Thermal treatment of soil co-contaminated with lube oil and heavy metals in a low-temperature two-stage fluidized bed incinerator

    International Nuclear Information System (INIS)

    Samaksaman, Ukrit; Peng, Tzu-Huan; Kuo, Jia-Hong; Lu, Chien-Hsing; Wey, Ming-Yen

    2016-01-01

    Highlights: • Low-temperature two-stage fluidized bed incineration was applied for soil remediation. • Co-firing of polyethylene with co-contaminated soil was studied. • Co-firing of polyethylene in soil remediation can promote residue quality. • The leachability of heavy metals passed the regulatory threshold values. - Abstract: This study presents the application of a low-temperature two-stage fluidized bed incinerator to remediate contaminants in the soil. The system was designed to control emissions of both gaseous pollutants and heavy metals during combustion. Soil co-contaminated with lube oil and heavy metals such as cadmium, chromium, copper, and lead was examined. Experiments were conducted by estimating various parameters such as operating temperature in the first-stage reactor (500–700 °C), ratio of sand bed height/diameter in the second-stage reactor (H/D: 3, 4, 6), and gas velocity (0.21–0.29 m/s). Heavy metal and gaseous pollutant emissions were also investigated during contaminated soil co-firing with polyethylene. The experimental results indicated that the destruction and removal efficiency of lube oil in treated soil products ranged from 98.27 to 99.93%. On the other hand, leaching tests of bottom ashes illustrated that heavy metals such as chromium, copper, and lead in leachates were complied with the regulations. For gaseous emissions, carbon monoxide concentrations decreased apparently with increasing ratio of sand bed height/diameter in the second-stage reactor. The increase of gas velocity had significant potential to generate the lowest carbon monoxide and particulate matter emissions. Nevertheless, during co-firing with polyethylene, emissions of organic pollutants such as benzene, toluene, ethylbenzene, and xylene and polycyclic aromatic hydrocarbons decrease by using the low-temperature two-stage fluidized bed incineration system.

  5. Research on the enhancement of biological nitrogen removal at low temperatures from ammonium-rich wastewater by the bio-electrocoagulation technology in lab-scale systems, pilot-scale systems and a full-scale industrial wastewater treatment plant.

    Science.gov (United States)

    Li, Liang; Qian, Guangsheng; Ye, Linlin; Hu, Xiaomin; Yu, Xin; Lyu, Weijian

    2018-04-17

    In cold areas, nitrogen removal performance of wastewater treatment plants (WWTP) declines greatly in winter. This paper systematically describes the enhancement effect of a periodic reverse electrocoagulation technology on biological nitrogen removal at low temperatures. The study showed that in the lab-scale systems, the electrocoagulation technology improved the biomass amount, enzyme activity and the amount of nitrogen removal bacteria (Nitrosomonas, Nitrobacter, Paracoccus, Thauera and Enterobacter). This enhanced nitrification and denitrification of activated sludge at low temperatures. In the pilot-scale systems, the electrocoagulation technology increased the relative abundance of cold-adapted microorganisms (Luteimonas and Trueperaceae) at low temperatures. In a full-scale industrial WWTP, comparison of data from winter 2015 and winter 2016 showed that effluent chemical oxygen demand (COD), NH 4 + -N, and NO 3 - -N reduced by 10.37, 3.84, and 136.43 t, respectively, throughout the winter, after installation of electrocoagulation devices. These results suggest that the electrocoagulation technology is able to improve the performance of activated sludge under low-temperature conditions. This technology provides a new way for upgrading of the performance of WWTPs in cold areas. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. The 3R anthracite clean coal technology: Economical conversion of brown coal to anthracite type clean coal by low temperature carbonization pre-treatment process

    Directory of Open Access Journals (Sweden)

    Someus Edward

    2006-01-01

    Full Text Available The preventive pre-treatment of low grade solid fuels is safer, faster, better, and less costly vs. the "end-of-the-pipe" post treatment solutions. The "3R" (Recycle-Reduce-Reuse integrated environment control technology provides preventive pre-treatment of low grade solid fuels, such as brown coal and contaminated solid fuels to achieve high grade cleansed fuels with anthracite and coke comparable quality. The goal of the 3R technology is to provide cost efficient and environmentally sustainable solutions by preventive pre-treatment means for extended operations of the solid fuel combustion power plants with capacity up to 300 MWe power capacities. The 3R Anthracite Clean Coal end product and technology may advantageously be integrated to the oxyfuel-oxy-firing, Foster Wheeler anthracite arc-fired utility type boiler and Heat Pipe Reformer technologies in combination with CO2 capture and storage programs. The 3R technology is patented original solution. Advantages. Feedstock flexibility: application of pre-treated multi fuels from wider fuel selection and availability. Improved burning efficiency. Technology flexibility: efficient and advantageous inter-link to proven boiler technologies, such as oxyfuel and arcfired boilers. Near zero pollutants for hazardous-air-pollutants: preventive separation of halogens and heavy metals into small volume streams prior utilization of cleansed fuels. >97% organic sulphur removal achieved by the 3R thermal pre-treatment process. Integrated carbon capture and storage (CCS programs: the introduction of monolitic GHG gas is improving storage safety. The 3R technology offers significant improvements for the GHG CCS conditions. Cost reduction: decrease of overall production costs when all real costs are calculated. Improved safety: application of preventive measures. For pre-treatment a specific purpose designed, developed, and patented pyrolysis technology used, consisting of a horizontally arranged externally

  7. Gelation Behavior Study of a Resorcinol–Hexamethyleneteramine Crosslinked Polymer Gel for Water Shut-Off Treatment in Low Temperature and High Salinity Reservoirs

    Directory of Open Access Journals (Sweden)

    Yongpeng Sun

    2017-07-01

    Full Text Available Mature oilfields usually encounter the problem of high watercut. It is practical to use chemical methods for water-shutoff in production wells, however conventional water-shutoff agents have problems of long gelation time, low gel strength, and poor stability under low temperature and high salinity conditions. In this work a novel polymer gel for low temperature and high salinity reservoirs was developed. This water-shutoff agent had controllable gelation time, adjustable gel strength and good stability performance. The crosslinking process of this polymer gel was studied by rheological experiments. The process could be divided into an induction period, a fast crosslinking period, and a stable period. Its gelation behaviors were investigated in detail. According to the Gel Strength Code (GSC and vacuum breakthrough method, the gel strength was displayed in contour maps. The composition of the polymer gel was optimized to 0.25~0.3% YG100 + 0.6~0.9% resorcinol + 0.2~0.4% hexamethylenetetramine (HMTA + 0.08~0.27% conditioner (oxalic acid. With the concentration increase of the polymer gel and temperature, the decrease of pH, the induction period became shorter and the crosslinking was more efficient, resulting in better stability performance. Various factors of the gelation behavior which have an impact on the crosslinking reaction process were examined. The relationships between each impact factor and the initial crosslinking time were described with mathematical equations.

  8. Vol. 5: Low Temperature Physics

    International Nuclear Information System (INIS)

    Sitenko, A.

    1993-01-01

    Problems of modern physics and the situation with physical research in Ukraine are considered. Programme of the conference includes scientific and general problems. Its proceeding are published in 6 volumes. The papers presented in this volume refer to low-temperature physics

  9. Certification testing at low temperatures

    International Nuclear Information System (INIS)

    Noss, P.W.; Ammerman, D.J.

    2004-01-01

    Regulations governing the transport of radioactive materials require that most hypothetical accident condition tests or analyses consider the effects of the environmental temperature that most challenges package performance. For many packages, the most challenging temperature environment is the cold condition (-29 C according to U.S. regulations), primarily because the low temperature causes the highest free drop impact forces due to the higher strength of many energy-absorbing materials at this temperature. If it is decided to perform low temperature testing, it is only necessary that the relevant parts of the package have the required temperature prior to the drop. However, the details of performing a drop at low temperature can have a large influence on testing cost and technical effectiveness. The selection of the test site, the chamber and type of chilling equipment, instrumentation, and even the time of year are all important. Control of seemingly minor details such as the effect on internal pressure, placement of monitoring thermocouples, the thermal time constant of the test article, and icing of equipment are necessary to ensure a successful low temperature test. This paper will discuss these issues and offer suggestions based on recent experience

  10. Science with low temperature detectors

    International Nuclear Information System (INIS)

    Sadoulet, B.; Lawrence Berkeley National Lab., CA; California Univ., Berkeley

    1996-01-01

    The novel technique of particle detection with low temperature detectors opens a number of new scientific opportunities. We review some of these, focusing on three generic applications: far infrared bolometry taking as an example the cosmic microwave background, X-ray spectroscopy for astrophysics and biological applications, and massive calorimeters for dark matter searches and neutrino physics. (orig.)

  11. Surface engineering and heat treatment

    International Nuclear Information System (INIS)

    Morton, P.H.

    1991-01-01

    This book is the proceedings of a Conference organised jointly by The Institute of Metals and The Centre for Exploitation of Science and Technology (CEST). It sets out to review this role and point the way to the future by collecting together a series of invited papers written by noted authorities in their fields. The opening review by CEST highlights the economic and industrial importance of Surface Engineering and is followed by a group of four articles devoted to specific branches of industry. Several technical papers then describe various aspects of the development of heat treatment over the last twenty-five years. These are followed by papers describing advances made possible by new technologies such as plasma, laser and ion beam. A separate abstract has been prepared for a paper on materials aspects of ion beam technology. (author)

  12. A physical model of the effect of irreversible changes in structure and properties of amorphous alloys caused by low-temperature treatment

    International Nuclear Information System (INIS)

    Zajchenko, S.G.; Glezer, A.M.

    2002-01-01

    A low temperature ΔT-effect physical model for amorphous metallic alloys (AMA) is developed. Using Ni-P, Fe-Co-Si-B, Co-Ni-Fe-Si-B, Fe-Si-B, Fe-Ni-Si-B, Fe-Cu-Nb-Si-B alloys the studies are carried out which results support basic concepts of the theory, namely: a motive force for atom drift, resulting in irreversible changes of a short-range order, is at the heart of longitudinal oscillations of AMA ribbon initiate the process of changing the initial short-range order. Variations of topological and short-range orders are responsible for a decrease in yield strength and Young modulus, a Curie point shift, an increase of saturation magnetization at an insignificant drop of coercive force or a significant drop of coercive force at a slight increase of saturation magnetization [ru

  13. Investigations of Low Temperature Time Dependent Cracking

    Energy Technology Data Exchange (ETDEWEB)

    Van der Sluys, W A; Robitz, E S; Young, B A; Bloom, J

    2002-09-30

    The objective of this project was to investigate metallurgical and mechanical phenomena associated with time dependent cracking of cold bent carbon steel piping at temperatures between 327 C and 360 C. Boiler piping failures have demonstrated that understanding the fundamental metallurgical and mechanical parameters controlling these failures is insufficient to eliminate it from the field. The results of the project consisted of the development of a testing methodology to reproduce low temperature time dependent cracking in laboratory specimens. This methodology was used to evaluate the cracking resistance of candidate heats in order to identify the factors that enhance cracking sensitivity. The resultant data was integrated into current available life prediction tools.

  14. Low temperature gaseous surface hardening of stainless steel

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Somers, Marcel A. J.

    2010-01-01

    The present contribution gives an overview of some of the technological aspects of low temperature thermochemical treatment of stainless steel. Examples of low temperature gaseous nitriding, carburising and nitrocarburising of stainless steel are presented and discussed. In particular......, the morphology, microstructure and characteristics of so-called expanite “layers” on stainless steel are addressed....

  15. Physiological and molecular mechanisms associated with cross tolerance between hypoxia and low temperature in Thaumatotibia leucotreta

    DEFF Research Database (Denmark)

    Boardman, Leigh; Sørensen, Jesper Givskov; Terblanche, John S

    2015-01-01

    identified to date. Using larvae of false codling moth Thaumatotibia leucotreta, a pest of southern Africa, we investigated the physiological and molecular responses to hypoxia or temperature stress pre-treatments, followed by a standard low temperature exposure. Survival rates were significantly influenced...... by pretreatment conditions, although T. leucotreta shows relatively high basal resistance to various stressors (4% variation in larval survival across all pre-treatments). Results showed that mild pre-treatments with chilling and hypoxia increased resistance to low temperatures and that these responses were...... correlated with increased membrane fluidity (increased UFA:SFA) and/or alterations in heat shock protein 70 (HSP70); while general mechanical stress (shaking) and heat (2 h at 35 C) do not elicit cross tolerance (no change in survival or molecular responses). We therefore found support for some limited cold...

  16. Strength and low temperature toughness of Fe-13%Ni-Mo alloys

    International Nuclear Information System (INIS)

    Ishikawa, Keisuke; Maruyama, Norio; Tsuya, Kazuo

    1978-01-01

    Mechanical tests were made on newly developed Fe-13%Ni-Mo alloys for eryogenic service. The effects of the additional elements were investigated from the viewpoint of the strength and the low temperature toughness. The alloys added by Al, Ti or V have the better balance of these properties. They did not show low temperature brittleness induced by cleavage fracture in Charpy impact test at 77 K. The microfractography showed the utterly dimple rupture patterns on the broken surface of all specimens. It would be supposed that the cleavage fracture stress is considerably higher than the flow stress. These alloys are superior to some commercial structural materials for low temperature use in the balance between the strength at 300 K and the toughness at 77 K. Additionally, it is noted that these experimental alloys have a good advantage in getting high strength and high toughness by the rather simple heat treatment. (auth.)

  17. Mechanical pumping at low temperature

    International Nuclear Information System (INIS)

    Perin, J.P.; Claudet, G.; Disdier, F.

    1995-01-01

    This novel concept consist of a mechanical pump able to run at low temperature (25K). Since gas density varies inversely with temperature, this pump would deliver much higher mass flow rate than at room temperature for a given size. Advantages of this concept are order of magnitude reduction in size, weight, when compared to a conventional pump scaled to perform the same mass flow rate at room temperature. This pump would be a solution to allow continuously tritium extraction and minimize the mass inventory. (orig.)

  18. Ammonia synthesis at low temperatures

    DEFF Research Database (Denmark)

    Rod, Thomas Holm; Logadottir, Ashildur; Nørskov, Jens Kehlet

    2000-01-01

    have been carried out to evaluate its feasibility. The calculations suggest that it might be possible to catalytically produce ammonia from molecular nitrogen at low temperatures and pressures, in particular if energy is fed into the process electrochemically. (C) 2000 American Institute of Physics.......Density functional theory (DFT) calculations of reaction paths and energies for the industrial and the biological catalytic ammonia synthesis processes are compared. The industrial catalyst is modeled by a ruthenium surface, while the active part of the enzyme is modeled by a MoFe6S9 complex...

  19. Heat treatment of nickel alloys

    International Nuclear Information System (INIS)

    Smith, D.F. Jr.; Clatworthy, E.F.

    1975-01-01

    A heat treating process is described that can be used to produce desired combinations of strength, ductility, and fabricability characteristics in heat resistant age-hardenable alloys having precipitation-hardening amounts of niobium, titanium, and/or tantalum in a nickel-containing matrix. (U.S.)

  20. Potential market and characteristics of low-temperature reactors

    International Nuclear Information System (INIS)

    Lerouge, B.

    1975-01-01

    The low-temperature (100 to 200 deg C) heat market for industrial applications and district heating is very important. Two main studies have been developed: a swimming pool reactor delivering water at 110 deg C and a prestressed concrete vessel reactor delivering water at 200 deg C [fr

  1. 29 CFR 1919.16 - Heat treatment.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Heat treatment. 1919.16 Section 1919.16 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) GEAR CERTIFICATION Certification of Vessels' Cargo Gear § 1919.16 Heat treatment. (a) All chains (other...

  2. Feasibility of geothermal heat use in the San Bernardino Municipal Wastewater Treatment Plant. Final report, September 1980-June 1981

    Energy Technology Data Exchange (ETDEWEB)

    Racine, W.C.; Larson, T.C.; Stewart, C.A.; Wessel, H.B.

    1981-06-01

    The results of the feasibility study for utilizing low temperature geothermal heat in the City of San Bernardino Wastewater Treatment Plant are summarized. The study is presented in terms of preliminary engineering design, economic analysis, institutional issues, environmental impacts, resource development, and system implementation.

  3. Wolte 5. low temperature electronics

    International Nuclear Information System (INIS)

    Balestra, F.; Dieudonne, F.; Jomaah, J.

    2002-01-01

    This book present the latest research and development results in advanced materials, technologies, devices, circuits and systems for low temperature electronics. The main themes of the papers are ranging from physics and fundamental aspects, modeling and simulation, to device and circuit design. The topics include advanced process and characterization, novel devices and cryogenic instrumentation. The papers are divided into nine sections, reflecting the main research efforts in different areas: i) deep submicron silicon MOSFETs, ii) alternative MOSFETs (SOI, innovating device architectures), iii) III-V devices, iv) other semiconductor devices (Ge devices, p-n junctions, IR sensors, semiconductor microcrystals), v) emerging devices and phenomena (nano Si-based devices, conduction and fluctuations mechanisms), vi) superconducting materials, vii) superconducting detectors, viii) superconducting devices and circuits (RSFQ, SIS mixers, metal-superconducting-semiconductor structures), ix) low temperature electronics for space applications. Six invited papers presented by internationally recognized authors, and 39 contributed papers are presented. The invited papers provide an excellent overview of today's status and progress, as well as tomorrow's challenges and trends in this important discipline for many cryogenic applications. (authors)

  4. Advances in the heat treatment of steels

    International Nuclear Information System (INIS)

    Morris, J.W. Jr.; Kim, J.I.; Syn, C.K.

    1978-06-01

    A number of important recent advances in the processing of steels have resulted from the sophisticated uses of heat treatment to tailor the microstructure of the steels so that desirable properties are established. These new heat treatments often involve the tempering or annealing of the steel to accompish a partial or complete reversion from martensite to austenite. The influence of these reversion heat treatments on the product microstructure and its properties may be systematically discussed in terms of the heat treating temperature in relation to the phase diagram. From this perspective, four characteristic heat treatments are defined: (1) normal tempering, (2) inter-critical tempering, (3) intercritical annealing, and (4) austenite reversion. The reactions occurring during each of these treatments are described and the nature and properties of typical product microstructures discussed, with specific reference to new commercial or laboratory steels having useful and exceptional properties

  5. Treatment of toxic and hazardous organic wastes by wet oxidation process with oxygenated water at low temperature; Trattamento dei rifiuti tossici e nocivi organici mediante il processo di ossidazione ad umido con acqua ossigenata a bassa temperatura

    Energy Technology Data Exchange (ETDEWEB)

    Piccinno, T; Salluzzo, A; Nardi, L [ENEA - Dipartimento Ciclo del Combustibile, Centro Ricerche Energia, Casaccia (Italy); Gili, M; Luce, A; Troiani, F [ENEA - Dipartimento Ciclo del Combustibile, Centro Ricerche Energia, Saluggia (Italy); Cornacchia, G [ENEA - Dipartimento Ciclo del Combustibile, Centro Ricerche Energia, Trisaia (Italy)

    1989-11-15

    The wet oxidation process using air or molecular oxygen is a well-known process from long time. It is suitable to oxidize several types of waste refractory to the usual biological, thermal and chemical treatments. The drastic operating conditions (high pressures and temperatures) prevented its industrial development. In the last years a new interest was assigned to the process for the treatment of nuclear wastes (organic resins and exhaust organic wastes); the treatment is carried out at widely reduced operating conditions (atmospheric pressure and boiling temperature) by means of metallic catalysts and hydrogen peroxide. With some limits, the wet oxidation with hydrogen peroxide at low temperature can be applied to conventional waste waters containing toxic organic compounds. In the present report are summarized the activities developed at ENEA Fuel Cycle Department by the task force 'Deox' constituted by laboratory and plant specialists in order to verify the application of the wet oxidation process to the treatment of the toxic wastes. (author)

  6. Hydrothermal carbonization of biomass waste under low temperature condition

    Directory of Open Access Journals (Sweden)

    Putra Herlian Eriska

    2018-01-01

    Full Text Available In this paper, the use of banana peel for energy purposes was investigated. Banana peel is a lignocellulosic waste since it is the most widely produced and consumed fruit in Indonesia. Among the others, hydrothermal carbonization (HTC was chosen as alternative themochemical process, suitable for high moisture biomass. Through a 1 L stirred reactor, hydrothermal treatments were performed under low temperature condition (190, 210 and 230 °C, residence times (30 and 60 min, and biomass to water ratio (1:3, 1:5, and 1:10. Three of product were collected from the process with primary material balance. Solid phase (hydrochar was evaluated in terms of calorific value, proximate and ultimate analysis. The results suggested that the hydrothermal carbonization of banana peel gave high heating value (HHV of 20.09 MJ/kg for its char after dried naturally.

  7. The Low temperature CFB gasifier

    DEFF Research Database (Denmark)

    Stoholm, P.; Nielsen, Rasmus Glar; Fock, Martin W.

    2003-01-01

    %) particle separation by the hot secondary cyclone. The next LT-CFB experiment, currently under preparation, is expected to be on either municipal/industrial waste or animal manure. Eventually a 500 kW LT-CFB test plant scheduled for commission during summer 2003, and the anticipated primary LT......The Low Temperature Circulating Fluidised Bed (LT-CFB) gasification process aims at avoiding problems due to ash deposition and agglomeration when using difficult fuels such as agricultural biomass and many waste materials. This, as well as very simple gas cleaning, is achieved by pyrolysing...... the fuel at around 650?C in a CFB reaction chamber and subsequently gasifying the char at around 730oC in a slowly fluidised bubbling bed chamber located in the CFB particle recirculation path. In this paper the novel LT-CFB concept is further described together with the latest test results from the 50 k...

  8. Low Temperature Hydrogen Antihydrogen Interactions

    International Nuclear Information System (INIS)

    Armour, E. A. G.; Chamberlain, C. W.

    2001-01-01

    In view of current interest in the trapping of antihydrogen (H-bar) atoms at low temperatures, we have carried out a full four-body variational calculation to determine s-wave elastic phase shifts for hydrogen antihydrogen scattering, using the Kohn Variational Principle. Terms outside the Born-Oppenheimer approximation have been taken into account using the formalism of Kolos and Wolniewicz. As far as we are aware, this is the first time that these terms have been included in an H H-bar scattering calculation. This is a continuation of earlier work on H-H-bar interactions. Preliminary results differ substantially from those calculated using the Born-Oppenheimer approximation. A method is outlined for reducing this discrepancy and taking the rearrangement channel into account.

  9. Mechanical pumping at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Perin, J.P.; Claudet, G.; Disdier, F.

    1994-12-31

    This new concept consists of a mechanical pump able to run at low temperature (25 K). Since gas density varies inversely with temperature, the pump could deliver much higher mass flow rate than at room temperature for a given size. Advantages of this concept are reduction of an order of magnitude in size and weight when compared to a conventional pump scaled to perform the same mass flow rate at room temperature. Results obtained at 80 K and 25 K with a Holweck type molecular drag pump of 100 mm diameter and with few stages of a turbomolecular pump running at the same temperatures, are given. This pump would be a solution to allow continuous tritium extraction and minimize the mass inventory for the ITER (International Tokamak Experiment Reactor). 5 figs., 2 tabs., 4 refs.

  10. Physiological and biochemical responses to low temperature stress ...

    African Journals Online (AJOL)

    ajl yemi

    2011-11-09

    Nov 9, 2011 ... Levels of electrolyte leak and MDA were lower than in UD189 or UD191. Poplar hybrid clones ... humidity, exposure, and water status and health conditions of ... consecutive low temperature treatment; and to detect variation ...

  11. Characteristics of SiOx-containing hard film prepared by low temperature plasma enhanced chemical vapor deposition using hexamethyldisilazane or vinyltrimethylsilane and post oxygen plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Yi-Syuan; Liu, Wan-Yu; Wu, Hsin-Ming [Department of Materials Engineering, Tatung University, Taipei, 104, Taiwan (China); Chen, Ko-Shao, E-mail: kschen@ttu.edu.tw [Department of Materials Engineering, Tatung University, Taipei, 104, Taiwan (China); Cech, Vladimir [Institute of Materials Chemistry, Brno University of Technology (Czech Republic)

    2017-03-01

    This study, monomers of hexamethyldisilazane (HMDSZ) and vinyltrimethylsilane (VTMS) were respectively used to deposit on the surface of polyethylene terephthalate (PET) substrate by plasma enhanced chemical vapor deposition. Oxygen plasma treatment follows the HMDSZ and VTMS deposition to produce a hydrophilic surface film on the deposited surface. Time for HMDSZ and VTMS plasma deposition was changed to investigate its influences on water contact angle, deposited film thickness, refractive index, and friction coefficient properties. The surface morphologies of the processed samples were observed by scanning electron microscope and their chemical compositions were measured by X-ray photoelectron spectroscopy. At 550 nm wavelength, the optical transmittance of PET after the HMDSZ treatment decreases from 89% to 83%, but increases from 89% to 95% for the VTMS treatment. With increase in HMDSZ and VTMS deposition times, the film thickness increases and the refractive index decreases. Result revealed by XPS, SiO{sub 2} film is formed on the sample surface after the O{sub 2} plasma treatment. The film adhesion capability by the HMDSZ+O{sub 2} and VTMS+O{sub 2} treatment was stronger than that by the HMDSZ and VTMS treatment only. The SiOx films produced by HMDSZ+O{sub 2} and VTMS+O{sub 2} treatment can increase the film hardness and improve light transmittance. - Highlights: • With increase in HMDSZ and VTMS deposition times, the film thickness increases and the refractive index decreases. • The optical transmittance of PET after the VTMS treatment increases from 89% to 95%. • The SiO{sub 2} films deposited by HMDSZ+O{sub 2} and VTMS+O{sub 2} plasma can increase the film hardness and improve light transmittance. • It is expected that they can be applied to the optical transmittance protective film on plastic substrate in the future.

  12. Low Temperature Surface Carburization of Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Sunniva R; Heuer, Arthur H; Sikka, Vinod K

    2007-12-07

    Low-temperature colossal supersaturation (LTCSS) is a novel surface hardening method for carburization of austenitic stainless steels (SS) without the precipitation of carbides. The formation of carbides is kinetically suppressed, enabling extremely high or colossal carbon supersaturation. As a result, surface carbon concentrations in excess of 12 at. % are routinely achieved. This treatment increases the surface hardness by a factor of four to five, improving resistance to wear, corrosion, and fatigue, with significant retained ductility. LTCSS is a diffusional surface hardening process that provides a uniform and conformal hardened gradient surface with no risk of delamination or peeling. The treatment retains the austenitic phase and is completely non-magnetic. In addition, because parts are treated at low temperature, they do not distort or change dimensions. During this treatment, carbon diffusion proceeds into the metal at temperatures that constrain substitutional diffusion or mobility between the metal alloy elements. Though immobilized and unable to assemble to form carbides, chromium and similar alloying elements nonetheless draw enormous amounts of carbon into their interstitial spaces. The carbon in the interstitial spaces of the alloy crystals makes the surface harder than ever achieved before by more conventional heat treating or diffusion process. The carbon solid solution manifests a Vickers hardness often exceeding 1000 HV (equivalent to 70 HRC). This project objective was to extend the LTCSS treatment to other austenitic alloys, and to quantify improvements in fatigue, corrosion, and wear resistance. Highlights from the research include the following: • Extension of the applicability of the LTCSS process to a broad range of austenitic and duplex grades of steels • Demonstration of LTCSS ability for a variety of different component shapes and sizes • Detailed microstructural characterization of LTCSS-treated samples of 316L and other alloys

  13. Low-temperature geothermal resources of Washington

    Energy Technology Data Exchange (ETDEWEB)

    Schuster, J.E. [Washington State Dept. of Natural Resources, Olympia, WA (United States). Div. of Geology and Earth Resources; Bloomquist, R.G. [Washington State Energy Office, Olympia, WA (United States)

    1994-06-01

    This report presents information on the location, physical characteristics, and water chemistry of low-temperature geothermal resources in Washington. The database includes 941 thermal (>20C or 68F) wells, 34 thermal springs, lakes, and fumaroles, and 238 chemical analyses. Most thermal springs occur in the Cascade Range, and many are associated with stratovolcanoes. In contrast, 97 percent of thermal wells are located in the Columbia Basin of southeastern Washington. Some 83.5 percent are located in Adams, Benton, Franklin, Grant, Walla Walla, and Yakima Counties. Yakima County, with 259 thermal wells, has the most. Thermal wells do not seem to owe their origin to local sources of heat, such as cooling magma in the Earth`s upper crust, but to moderate to deep circulation of ground water in extensive aquifers of the Columbia River Basalt Group and interflow sedimentary deposits, under the influence of a moderately elevated (41C/km) average geothermal gradient.

  14. The Low Temperature Microgravity Physics Facility Project

    Science.gov (United States)

    Chui, T.; Holmes, W.; Lai, A.; Croonquist, A.; Eraker, J.; Abbott, R.; Mills, G.; Mohl, J.; Craig, J.; Balachandra, B.; hide

    2000-01-01

    We describe the design and development of the Low Temperature Microgravity Physics Facility, which is intended to provide a unique environment of low temperature and microgravity for the scientists to perform breakthrough investigations on board the International Space Station.

  15. MATHEMATICAL MODELING OF HEATING RATE PRODUCT AT HIGH HEAT TREATMENT

    Directory of Open Access Journals (Sweden)

    M. M. Akhmedova

    2014-01-01

    Full Text Available Methods of computing and mathematical modeling are all widely used in the study of various heat exchange processes that provide the ability to study the dynamics of the processes, as well as to conduct a reasonable search for the optimal technological parameters of heat treatment.This work is devoted to the identification of correlations among the factors that have the greatest effect on the rate of heating of the product at hightemperature heat sterilization in a stream of hot air, which are chosen as the temperature difference (between the most and least warming up points and speed cans during heat sterilization.As a result of the experimental data warming of the central and peripheral layers compote of apples in a 3 liter pot at high-temperature heat treatment in a stream of hot air obtained by the regression equation in the form of a seconddegree polynomial, taking into account the effects of pair interaction of these parameters. 

  16. The Low Temperature Microgravity Physics Experiments Project

    Science.gov (United States)

    Holmes, Warren; Lai, Anthony; Croonquist, Arvid; Chui, Talso; Eraker, J. H.; Abbott, Randy; Mills, Gary; Mohl, James; Craig, James; Balachandra, Balu; hide

    2000-01-01

    The Low Temperature Microgravity Physics Facility (LTMPF) is being developed by NASA to provide long duration low temperature and microgravity environment on the International Space Station (ISS) for performing fundamental physics investigations. Currently, six experiments have been selected for flight definition studies. More will be selected in a two-year cycle, through NASA Research Announcement. This program is managed under the Low Temperature Microgravity Physics Experiments Project Office at the Jet Propulsion Laboratory. The facility is being designed to launch and returned to earth on a variety of vehicles including the HII-A and the space shuttle. On orbit, the facility will be connected to the Exposed Facility on the Japanese Experiment Module, Kibo. Features of the facility include a cryostat capable of maintaining super-fluid helium at a temperature of 1.4 K for 5 months, resistance thermometer bridges, multi-stage thermal isolation system, thermometers capable of pico-Kelvin resolution, DC SQUID magnetometers, passive vibration isolation, and magnetic shields with a shielding factor of 80dB. The electronics and software architecture incorporates two VME buses run using the VxWorks operating system. Technically challenging areas in the design effort include the following: 1) A long cryogen life that survives several launch and test cycles without the need to replace support straps for the helium tank. 2) The minimization of heat generation in the sample stage caused by launch vibration 3) The design of compact and lightweight DC SQUID electronics. 4) The minimization of RF interference for the measurement of heat at pico-Watt level. 5) Light weighting of the magnetic shields. 6) Implementation of a modular and flexible electronics and software architecture. The first launch is scheduled for mid-2003, on an H-IIA Rocket Transfer Vehicle, out of the Tanegashima Space Center of Japan. Two identical facilities will be built. While one facility is onboard

  17. The Low Temperature CFB Gasifier

    DEFF Research Database (Denmark)

    Stoholm, P.; Nielsen, Rasmus Glar; Richardt, K.

    2004-01-01

    straw, animal manure and waste and for co-firing the product gas in existing, e.g. coal fired power plant boilers. The aim is to prevent fouling, agglomeration and high temperature corrosion caused by potassium and chlorine and other fuel components when producing electricity. So far 92 hours......The Low Temperature Circulating Fluidised Bed (LT-CFB) gasification process is described together with the 50 kW and the 500 kW test plants and latest test results. The LT-CFB process is especially developed for medium and large scale (few to >100 MW) gasification of problematic bio-fuels like...... of experiments with the 50 kW test plant with two extremely difficult types of straw has shown low char losses and high retentions of ash including e.g. potassium. Latest 27 hours of experiments with dried, high ash pig- and hen manure has further indicated the concepts high fuel flexibility. The new 500 kW test...

  18. Low-temperature nuclear orientation

    International Nuclear Information System (INIS)

    Stone, N.J.; Postma, H.

    1986-01-01

    This book comprehensively surveys the many aspects of the low temperature nuclear orientation method. The angular distribution of radioactive emissions from nuclei oriented by hyperfine interactions in solids, is treated experimentally and theoretically. A general introductory chapter is followed by formal development of the theory of the orientation process and the anisotropic emission of decay products from oriented nuclei, applied to radioactive decay and to reactions. Five chapters on applications to nuclear physics cover experimental studies of alpha, beta and gamma emission, nuclear moment measurement and level structure information. Nuclear orientation studies of parity non-conservation and time reversal asymmetry are fully described. Seven chapters cover aspects of hyperfine interactions, magnetic and electric, in metals, alloys and insulating crystals, including ordered systems. Relaxation phenomena and the combined technique of NMR detection using oriented nuclei are treated at length. Chapters on the major recent development of on-line facilities, giving access to short lived nuclei far from stability, on the use of nuclear orientation for thermometry below 1 Kelvin and on technical aspects of the method complete the main text. Extensive appendices, table of relevant parameters and over 1000 references are included to assist the design of future experiments. (Auth.)

  19. Heat Treatment of Tools in Light Industry

    Science.gov (United States)

    Petukhov, V. A.

    2005-09-01

    Heat treatment processes for some tools (knitting needles, travelers for thimbles of spinning and doubling frames, thread-forming spinnerets) used for the production of cloths, hosiery, and other articles) in the knitting and textile industries are considered. Problems of the choice of steel and the kind and parameters of heat treatment are discussed in connection with the special features of tool design and operating conditions.

  20. High degree reduction and restoration of graphene oxide on SiO2 at low temperature via remote Cu-assisted plasma treatment

    Science.gov (United States)

    Obata, Seiji; Sato, Minoru; Akada, Keishi; Saiki, Koichiro

    2018-06-01

    A high throughput synthesis method of graphene has been required for a long time to apply graphene to industrial applications. Of the various synthesis methods, the chemical exfoliation of graphite via graphene oxide (GO) is advantageous as far as productivity is concerned; however, the quality of the graphene produced by this method is far inferior to that synthesized by other methods, such as chemical vapor deposition on metals. Developing an effective reduction and restoration method for GO on dielectric substrates has been therefore a key issue. Here, we present a method for changing GO deposited on a dielectric substrate into high crystallinity graphene at 550 °C this method uses CH4/H2 plasma and a Cu catalyst. We found that Cu remotely catalyzed the high degree reduction and restoration of GO on SiO2 and the effect ranged over at least 8 mm. With this method, field-effect transistor devices can be fabricated without any post treatment such as a transfer process. This plasma treatment increased electron and hole mobilities of GO to 480 cm2 V‑1 s‑1 and 460 cm2 V‑1 s‑1 respectively; these values were more than 50 times greater than that of conventional reduced GO. Furthermore, the on-site conversion ensured that the shape of the GO sheets remained unchanged after the treatment. This plasma treatment realizes the high throughput synthesis of a desired shaped graphene on any substrate without any residue and damage being caused by the transfer process; as such, it expands the potential applicability of graphene.

  1. Effects of combination treatments of radiation and salt on the shelf life extension of hilsha fish (Hilsa ilisha) at low temperature

    International Nuclear Information System (INIS)

    Hossain, M.M.; Alam, M.Z.; Karim, A.; Rashid, H.; Khan, A.H.

    1991-01-01

    Investigations were made on the application of combination treatments of radiation with common salt at the doses of 50, 100 and 150 krad on the shelflife extension of hilsha fish slices at 5 deg. C. Quality assessments were made by chemical, bacteriological and sensory evaluations. The storage life of control samples of the same storage temperature was about 3 weeks, whereas salted samples treated with 100 Krad were acceptable up to 9 weeks. Results of bacteriological tests agreed well with sensory panel evaluations but chemical parameters such as TVB and TMA were not suitable index for quality assessment of irradiated salted fish samples

  2. Heat-treatment and heat-to-heat variations in the fracture toughness of Alloy 718

    International Nuclear Information System (INIS)

    Mills, W.J.

    1981-07-01

    The effect of heat-treatment and heat-to-heat variations on the J Ic fracture toughness response of Alloy 718 was examined at room and elevated temperatures using the multiple-specimen R-curve technique. Six heats of alloy 718 were tested in the conventional and modified heat-treated conditions. The fracture toughness response for the modified superalloy was found to be superior to that exhibited by the conventional material. Heat-to-heat variations in the J Ic response of Alloy 718 were observed in both heat-treated conditions; the modified treatment exhibited much larger variability. The J Ic and corresponding K Ic fracture toughness values were analyzed statistically to establish minimum expected toughness, values for use in design and safety analyses. 26 refs., 10 figs., 9 tabs

  3. LOW TEMPERATURE CATHODE SUPPORTED ELECTROLYTES

    Energy Technology Data Exchange (ETDEWEB)

    Harlan U. Anderson

    2000-03-31

    This project has three main goals: Thin Films Studies, Preparation of Graded Porous Substrates and Basic Electrical Characterization and Testing of Planar Single Cells. During this time period substantial progress has been made in developing low temperature deposition techniques to produce dense, nanocrystalline yttrium-stabilized zirconia films on both dense oxide and polymer substrates. Progress has been made in the preparation and characterization of thin electrolytes and porous LSM substrates. Both of these tasks are essentially on or ahead of schedule. In our proposal, we suggested that the ZrO{sub 2}/Sc system needed to be considered as a candidate as a thin electrolyte. This was because microcrystalline ZrO{sub 2}/Sc has a significantly higher ionic conductivity than YSZ, particularly at the lower temperatures. As a result, some 0.5 micron thick film of ZrO{sub 2}/16% Sc on an alumina substrate (grain size 20nm) was prepared and the electrical conductivity measured as a function of temperature and oxygen activity. The Sc doped ZrO{sub 2} certainly has a higher conductivity that either 20nm or 2400nm YSZ, however, electronic conductivity dominates the conductivity for oxygen activities below 10{sup -15}. Whereas for YSZ, electronic conductivity is not a problem until the oxygen activity decreases below 10{sup -25}. These initial results show that the ionic conductivity of 20nm YSZ and 20nm ZrO{sub 2}/16% Sc are essentially the same and the enhanced conductivity which is observed for Sc doping in microcrystalline specimens is not observed for the same composition when it is nanocrystalline. In addition they show that the electronic conductivity of Sc doped ZrO{sub 2} is at least two orders of magnitude higher than that observed for YSZ. The conclusion one reaches is that for 0.5 to 1 micron thick nanocrystalline films, Sc doping of ZrO{sub 2} has no benefits compared to YSZ. As a result, electrolyte films of ZrO{sub 2}/Sc should not be considered as candidates

  4. Interactions between goethite particles subjected to heat treatment

    DEFF Research Database (Denmark)

    Madsen, Daniel Esmarch; Hansen, Mikkel Fougt; Koch, C.B.

    2008-01-01

    We have studied the effect of heating on the magnetic properties of particles of nanocrystalline goethite by use of Mossbauer spectroscopy. Heating at 150 degrees C for 24 h leads to a change in the quadrupole shift in the low-temperature spectra, indicating a rotation of the sublattice...... magnetization directions. Fitting of quantiles, derived from the asymmetrically broadened spectra between 80 and 300 K, to the superferromagnetism model indicates that this change is due to a stronger magnetic coupling between the particles....

  5. Washing water treatment process for UF{sub 6} cylinder by adjusting evaporation technology in a low temperature and low pressure

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki-tae; Ju, Young-jong; Cho, Nam-chan [KEPCO Nuclear Fuel Co., Daejeon (Korea, Republic of); Kim, Yun-kwan; Jin, Chang-suk [Jeontech CO., Suwon (Korea, Republic of)

    2016-10-15

    The liquid waste is treated in this procedure; 1) Add NaOH to the liquid waste and filter the mixture with a screen. 2) Screened residue is dried and then stored in a uranium storage. 3) liquid part is moved to a storage tank and radioactivity is measured in the liquid. 5) If the concentration of radioactivity is lower than corresponding regulation limit, the liquid moved to a reaction tank and evaporated with additional low concentration HF in 105℃. 6) Radioactivity of distillate is measured and the value is lower than regulation, it is treated with a thermal decomposition process and discharged to the atmosphere in gas state. 7) Solid waste produced in the evaporation step is managed as solid nuclear waste. The treatment procedure mentioned above has disadvantageous points, producing large amount of solid waste as well as, high energy and chemical consumption. In this study, liquid waste from a real scaled cylinder wash process is applied to evaporation system to confirm feasibility of the application of evaporation and, to reduce waste production and energy consumption. Liquid radioactive wastewater from a real scaled UF6 cylinder wash process was applied to evaporation treatment system. Radioactive concentration in gross alpha was removed 99.9% in the evaporation system. And the concentration in distillate was lower than the discharge regulation. Removal of U-235 was 99.9% in the process. And 15 other kinds of radionuclides in the raw wastewater were removed completely. Secondary waste production of the evaporation system is 15g/L.

  6. 49 CFR 179.400-12 - Postweld heat treatment.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Postweld heat treatment. 179.400-12 Section 179... and 107A) § 179.400-12 Postweld heat treatment. (a) Postweld heat treatment of the inner tank is not... be attached before postweld heat treatment. Welds securing the following need not be postweld heat...

  7. Microstructural Characterization of Low Temperature Gas Nitrided Martensitic Stainless Steel

    DEFF Research Database (Denmark)

    Fernandes, Frederico Augusto Pires; Christiansen, Thomas Lundin; Somers, Marcel A. J.

    2015-01-01

    The present work presents microstructural investigations of the surface zone of low temperature gas nitrided precipitation hardening martensitic stainless steel AISI 630. Grazing incidence X-ray diffraction was applied to investigate the present phases after successive removal of very thin sections...... of the sample surface. The development of epsilon nitride, expanded austenite and expanded martensite resulted from the low temperature nitriding treatments. The microstructural features, hardness and phase composition are discussed with emphasis on the influence of nitriding duration and nitriding potential....

  8. INFLUENCE OF A LOW TEMPERATURE AGEING ON THE ...

    African Journals Online (AJOL)

    The effect of a low temperature ageing treatment on the hardness, tensile and corrosion characteristics of sand cast Al-6.5%Si-0.35%Mg alloy was studied. The temper conditions are low temperature ageing at 90oC, 95oC, 100oCand 105oC respectively followed by ageing to 180oC for 2 hrs. This was compared with the ...

  9. LOW TEMPERATURE CATHODE SUPPORTED ELECTROLYTES

    Energy Technology Data Exchange (ETDEWEB)

    Harlan U. Anderson; Wayne Huebner; Igor Kosacki

    2001-09-30

    endeavors have lead us to a solution which we think is quite unique and should allow us to obtain flaw free dense films of thickness in the 0.5 to 5 {micro}m range at processing temperatures {le} 900{sup o}. The process involves the deposition of a slurry of nanocrystalline YSZ onto a presintered porous LSM substrate. The key element in the deposition is that the slurry contains sufficient YSZ polymer precursor to allow adhesion of the YSZ particles to each other and the surface after annealing at about 600 C. This allows the formation of a porous film of 0.5 to 5 {micro}m thick which adheres to the surface. After formation of this film, YSZ polymer precursor is allowed to impregnate the porous surface layer (capillary forces tend to confine the polymer solution in the nanoporous layer). After several impregnation/heat treatment cycles, a dense film results. Within the next few months, this process should be developed to the point that single cell measurements can be made on 0.5 to 5 {micro}m films on a LSM substrate. This type of processing allows the formation of essentially flaw free films over areas > 1 cm{sup 2}.

  10. Effect of low-temperature long-time and high-temperature short-time blanching and frying treatments on the French fry quality of six Irish potato cultivars.

    Science.gov (United States)

    Ngobese, Nomali Ziphorah; Workneh, Tilahun Seyoum; Siwela, Muthulisi

    2017-02-01

    Processing conditions are an important determinant of French fry quality. However, the effect of low-temperature long-time (LTLT) and high-temperature short-time (HTST) blanching and frying treatments has not been investigated in many cultivars. The current study investigates the effect of the sequential application of these treatments on French fries processed from six Irish potato cultivars (Fianna, Innovator, Mondial, Navigator, Panamera and Savanna). Blanching was effected at 75 °C for 10 min or 85 °C for 5 min and frying was effected at 160 °C for 2 min or 180 °C for 1 min. These treatments resulted in significant differences in the quality of the fries across the cultivars. The blanching treatments had a greater impact on the French fry quality than the frying treatments. LTLT blanching resulted in lower oil (12-13% fresh mass basis [fmb]), and higher protein (3.5-4.3% fmb) and mineral content in the French fries processed from Innovator, compared to HTST blanching. This was accompanied by a crispier crust, which required a greater puncture force (1.2-2.1 N) for penetration. Blanching with the LTLT treatment before HTST frying resulted in French fries that were the most acceptable to consumers and these were from Fianna, Innovator and Mondial. The current study demonstrates that the effect of French fry processing conditions is cultivar-dependent.

  11. The relief of microtherm inhibition for p-fluoronitrobenzene mineralization using electrical stimulation at low temperatures.

    Science.gov (United States)

    Zhang, Xueqin; Feng, Huajun; Liang, Yuxiang; Zhao, Zhiqing; Long, Yuyang; Fang, Yuan; Wang, Meizhen; Yin, Jun; Shen, Dongsheng

    2015-05-01

    Low temperature aggravates biological treatment of refractory p-fluoronitrobenzene (p-FNB) because of microtherm inhibition of microbial activity. Considering the potential characterization of energy supply for microbial metabolism and spurring microbial activity by electrical stimulation, a bioelectrochemical system (BES) was established to provide sustaining electrical stimulation for p-FNB mineralization at a low temperature. Electrical stimulation facilitated p-FNB treatment and bioelectrochemical reaction rate constants for the removal and defluorination of p-FNB at 10 °C were 0.0931 and 0.0054 h(-1), which were higher than the sums of the rates found using a biological system and an electrocatalytic system by 62.8 and 64.8%, respectively. At a low temperature, microbial activity in terms of dehydrogenase and ATPase was found to be higher with electrical stimulation, being 121.1 and 100.1% more active than that in the biological system. Moreover, stronger antioxidant ability was observed in the BES, which implied a better cold-resistance and relief of microtherm inhibition by electrical stimulation. Bacterial diversity analysis revealed a significant evolution of microbial community by electrical stimulation, and Clostridia was uniquely enriched. One bacterial sequence close to Pseudomonas became uniquely predominant, which appeared to be crucial for excellent p-FNB treatment performance in the BES at a low temperature. Economic evaluation revealed that the energy required to mineralize an extra mole of p-FNB was found to be 247 times higher by heating the system than by application of electrical stimulation. These results indicated that application of electrical stimulation is extremely promising for treating refractory waste at low temperatures.

  12. Design for a low temperature ion implantation and luminescence cryostat

    International Nuclear Information System (INIS)

    Noonan, J.R.; Kirkpatrick, C.G.; Myers, D.R.; Streetman, B.G.

    1976-01-01

    Several simple design changes of a conventional liquid helium optical Dewar can significantly improve the cryostat's versatility for use in low temperature particle irradiation. A bellows assembly provides precise sample positioning and allows convenient access for electrical connections. A heat exchanger consisting of thin walled tubing with a 'goose neck' bend provides a simple, effective means of cooling the sample as well as excellent thermal isolation of the sample holder from the coolant reservoir during controlled anneals. The addition of a vane-type vacuum valve, optical windows, and a rotatable tailpiece facilitates the study of optical properties of materials following low temperature ion implantation. (author)

  13. Failures of tool steels after heat treatments

    International Nuclear Information System (INIS)

    Nunez-Gonzalez, G.

    1990-01-01

    The main objective of the work was to determine the most common defects occuring in tool steels of the AISI D-2, S-1, 0-1 and W-2 series during thermal treatment. Defects were evaluated by metallographic analyses, a method used to determine and recognize micro structural defects and their origin in order to be able to eliminate and correct some of the stages that are caused by heat treatment. Results show a large number of defects due to irregularities during thermal heating such as excess or lack of temperature, heating time, and atmosphere, rectifying and handling in service and, to a lesser extent, poor design. In conclusion, with the results obtained for each of the thermal treatments it is necessary to define, particularly the values each of these variables should have since they affect the material properties. (Author)

  14. Fabrication of Nb_3Al superconductor by the optimized mechanical alloying method with low temperature

    International Nuclear Information System (INIS)

    Zhang, Y.; Lin, W.J.; Xu, L.Y.; Yang, D.W.; Chen, Y.L.; Li, P.Y.; Pan, X.F.; Yan, G.; Zhao, Y.

    2016-01-01

    Highlights: • Due to a much better strain tolerance than Nb_3Sn, Nb_3Al has been considered as an excellent candidate for making high field magnets. At present, the Nb_3Al superconducting wires were prepared mainly by the Jelly-roll method combined with a rapid heating and quenching (RHQ) heat treatment at around 2000 °C. In this study, Nb_3Al superconductor with T_c of 15.6 K is directly prepared with a mechanical alloying method followed by a low temperature annealing at 800 to 900 °C. Our results hint the possibility that Nb_3Al superconducting wire with high performance can be prepared below the melting point of Cu (1080 °C) by a conventional powder in tube (PIT) method, thus effectively avoiding high temperature heat treatment and RHQ device. - Abstract: Mechanical alloying was used to synthesize Nb_3Al superconductor successfully, and the process was optimization under various preparation conditions. In the current study, Nb_3Al superconductor with T_c of 15.6 K was directly prepared from high quality Nb (Al) solid solution by mechanical alloying method and heat treatment at a low temperature of 800 to 900 °C. The results showed that Nb_3Al superconducting wire with high performance could be prepared after heat treatment below the melting point of Cu (1080°C) and using Nb (Al) solid solution and conventional powder in tube (PIT) method, thus effectively avoiding ultra-high temperature heat treatment and special rapid heating and quenching(RHQ) device.

  15. Lowcost automated control for steel heat treatments

    International Nuclear Information System (INIS)

    Zambaldi, Edimilson; Magalhães, Ricardo R.; Barbosa, Bruno H.G.; Silva, Sandro P. da; Ferreira, Danton D.

    2017-01-01

    Highlights: • Control the furnace temperature measured by thermocouple and adjusts it. • Activating the furnace resistors through Pulse Width Modulation. • Appling heat treatments to steels by a low-cost controller. - Abstract: The aim of this paper is to propose a low cost, automated furnace control system for the heat treatment of steel. We used an open source electronic prototyping platform to control the furnace temperature, thus reducing human interaction during the heat process. The platform can be adapted to non-controlled commercial furnaces, which are often used by small businesses. A Proportional-Integral-Derivative (PID) controller was implemented to regulate the furnace temperature based on a defined heat treatment cycle. The embedded system activates the furnace resistors through Pulse Width Modulation (PWM), allowing for control of electrical power supplied to the furnace. Hardening and tempering were performed on standard steel samples using a traditional method (visual inspection without temperature control) as well the embedded system with PID feedback control. The results show that the proposed system can reproduce an arbitrary heat treatment curve with accuracy and provide the desired final hardness as inferred through metallographic analysis. In addition, we observed a 6% saving in energy consumption using the proposed control system. Furthermore, the estimated cost to implement the system is 42% lower than a commercial controller model implemented in commercial furnaces.

  16. 49 CFR 179.220-11 - Postweld heat treatment.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Postweld heat treatment. 179.220-11 Section 179... Postweld heat treatment. (a) Postweld heat treatment of the inner container is not a specification requirement. (b) Postweld heat treatment of the cylindrical portions of the outer shell to which the anchorage...

  17. 49 CFR 179.500-6 - Heat treatment.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Heat treatment. 179.500-6 Section 179.500-6...-6 Heat treatment. (a) Each necked-down tank shall be uniformly heat treated. Heat treatment shall... treatment of alternate steels shall be approved. All scale shall be removed from outside of tank to an...

  18. Low temperature humidification dehumidification desalination process

    International Nuclear Information System (INIS)

    Al-Enezi, Ghazi; Ettouney, Hisham; Fawzy, Nagla

    2006-01-01

    The humidification dehumidification desalination process is viewed as a promising technique for small capacity production plants. The process has several attractive features, which include operation at low temperature, ability to utilize sustainable energy sources, i.e. solar and geothermal, and requirements of low technology level. This paper evaluates the characteristics of the humidification dehumidification desalination process as a function of operating conditions. A small capacity experimental system is used to evaluate the process characteristics as a function of the flow rate of the water and air streams, the temperature of the water stream and the temperature of the cooling water stream. The experimental system includes a packed humidification column, a double pipe glass condenser, a constant temperature water circulation tank and a chiller for cooling water. The water production is found to depend strongly on the hot water temperature. Also, the water production is found to increase upon the increase of the air flow rate and the decrease of the cooling water temperature. The measured air and water temperatures, air relative humidity and the flow rates are used to calculate the air side mass transfer coefficient and the overall heat transfer coefficient. Measured data are found to be consistent with previous literature results

  19. Low temperature study of nonstoichiometric titanium carbide

    International Nuclear Information System (INIS)

    Tashmetov, M.Yu.

    2005-05-01

    By low temperature neutron diffraction method was studied structure in nonstoichiometric titanium carbide from room temperature up to 12K. It is found of low temperature phase in titanium carbide- TiC 0.71 . It is established region and borders of this phase. It is determined change of unit cell parameter. (author)

  20. Low-temperature plasma modelling and simulation

    NARCIS (Netherlands)

    Dijk, van J.

    2011-01-01

    Since its inception in the beginning of the twentieth century, low-temperature plasma science has become a major ¿eld of science. Low-temperature plasma sources and gas discharges are found in domestic, industrial, atmospheric and extra-terrestrial settings. Examples of domestic discharges are those

  1. Thermal conductivity at very low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Locatelli, M [CEA Centre d' Etudes Nucleaires de Grenoble, 38 (France). Service des Basses Temperatures

    1976-06-01

    The interest of low and very low temperatures in solid physics and especially that of thermal measurements is briefly mentioned. Some notes on the thermal conductivity of dielectrics, the method and apparatus used to measure this property at very low temperatures (T<1.5K) and some recent results of fundamental and applied research are then presented.

  2. Assembly for melting and heat treatment

    International Nuclear Information System (INIS)

    Blumenfeld, M.

    1976-11-01

    Laboratory scale production of alloys having a precise alloying materials content and the exact heat treatment of metallurgical specimens are discussed. The design and assembly of two relevant instruments are described. These instruments include a laboratory vacuum induction furnace and a specially designed glass lathe, that enables even an unskilled operator to encapsulate and seal metallurgical specimens in glass capsules. (author)

  3. Effect of heat treatment temperature on microstructure

    Indian Academy of Sciences (India)

    The results of electrochemical performance measurements for the HCSs as anode material for lithium ion batteries indicate that the discharge capacity of the HCSs is improved after heat treatment at 800°C compared with the as-prepared HCSs and have a maximum value of 357 mAh/g and still retains 303 mAh/g after 40 ...

  4. Low-temperature plasma techniques in surface modification of biomaterials

    International Nuclear Information System (INIS)

    Feng Xiangfen; Xie Hankun; Zhang Jing

    2002-01-01

    Since synthetic polymers usually can not meet the biocompatibility and bio-functional demands of the human body, surface treatment is a prerequisite for them to be used as biomaterials. A very effective surface modification method, plasma treatment, is introduced. By immobilizing the bio-active molecules with low temperature plasma, polymer surfaces can be modified to fully satisfy the requirements of biomaterials

  5. Sensory characteristics of meat cooked for prolonged times at low temperature

    DEFF Research Database (Denmark)

    Christensen, Line Bach; Gunvig, Annemarie; Tørngren, Mari Ann

    2012-01-01

    species, and cooking loss increased with increasing temperature. A done appearance was developed with increasing heating time at 58 °C in pork and beef, while in chicken the done appearance was only affected by temperature. Flavor attributes were less affected by the LTLT treatment for all species......The present study evaluated the sensory characteristics of low temperature long time (LTLT) treated Semitendinosus from pork and beef and Pectoralis profundus from chicken. Semitendinosus and Pectoralis profundus muscles were heat treated at 53°C and 58°C for Tc + 6 h, Tc + 17 h, and Tc + 30 h...... (only Semitendinosus from pork and beef). Tc was the time for the samples to equalize with the temperature in the water bath. Tenderness increased with increasing heating temperature and time in pork and beef, but not in chicken. Juiciness decreased with increasing heating temperature and time in all...

  6. Heat pumps

    CERN Document Server

    Brodowicz, Kazimierz; Wyszynski, M L; Wyszynski

    2013-01-01

    Heat pumps and related technology are in widespread use in industrial processes and installations. This book presents a unified, comprehensive and systematic treatment of the design and operation of both compression and sorption heat pumps. Heat pump thermodynamics, the choice of working fluid and the characteristics of low temperature heat sources and their application to heat pumps are covered in detail.Economic aspects are discussed and the extensive use of the exergy concept in evaluating performance of heat pumps is a unique feature of the book. The thermodynamic and chemical properties o

  7. Effect of Heat Shock Treatment and Aloe Vera Coating to Chilling Injury Symptom in Tomato (Lycopersicon asculantum Mill.

    Directory of Open Access Journals (Sweden)

    Sutrisno

    2012-04-01

    Full Text Available This research was undertaken to determine the effect of length in heat shock and edible coating as pre-storage treatment to Chilling Injury (CI symptom reflected by ion leakage induced and quality properties in tomato (Lycopersicon asculantum Mill.. Heat Shock Treatment (HST was conducted at three different levels of length, which were, 20; 40 and 60 min. Edible coating was conducted using aloe vera gel. The result showed that HST and Aloe Vera Coating (AVC were more effective to reduce CI symptom at lower chilling storage. Prolong exposure to heated water may delay climacteric peak. The length of heat shock, AVC treatment and low temperature storage significantly affected the tomato quality parameter but not significantly different for each treatment except weight loss. HST for 20 min at ambient temperature was significantly different to other treatment.

  8. Some experiments in low-temperature thermometry

    International Nuclear Information System (INIS)

    Fogle, W.E.

    1982-11-01

    A powdered cerous magnesium nitrate (CMN) temperature scale has been developed in the 0.016 to 3.8 K region which represents an interpolation between the 3 He/ 4 He (T 62 /T 58 ) vapor pressure scale and absolute temperatures in the millikelvin region as determined with a 60 Co in hcp Co nuclear orientation thermometer (NOT). Both ac and dc susceptibility thermometers were used in these experiments. The ac susceptibility of a 13 mg CMN-oil slurry was measured with a mutual inductance bridge employing a SQUID null detector while the dc susceptibility of a 3 mg slurry was measured with a SQUID/flux transformer combination. To check the internal consistency of the NOT, γ-ray intensities were measured both parallel and perpendicular to the Co crystal c-axis. The independent temperatures determined in this fashion were found to agree to within experimental error. For the CMN thermometers employed in these experiments, the susceptibility was found to obey a Curie-Weiss law with a Weiss constant of Δ = 1.05 +- 0.1 mK. The powdered CMN scale in the 0.05 to 1.0 K region was transferred to two germanium resistance thermometers for use in low-temperature specific heat measurements. The integrity of the scale was checked by examining the temperature dependence of the specific heat of high purity copper in the 0.1 to 1 K region. In more recent experiments in this laboratory, the scale was also checked by a comparison with the National Bureau of Standards cryogenic temperature scale (NBS-CTS-1). The agreement between the two scales in the 99 to 206 mK region was found to be on the order of the stated accuracy of the NBS scale

  9. Evaluation of contaminated soil remediation by low temperature thermal desorption

    International Nuclear Information System (INIS)

    Gibbs, L.; Punt, M.

    1993-01-01

    Soil contaminated with diesel and aviation fuels has been excavated and stored at a Canadian Forces Base in Ontario. Because of the volatile nature of this contamination, it was determined that low temperature thermal desorption (LTTD) would be an effective method of remediating this soil. A full scale evaluation of LTTD technology was conducted at the base to determine its acceptability for other sites. In the LTTD process, soil enters a primary treatment unit and is heated to a sufficiently high temperature to volatilize the hydrocarbon contaminants. Offgases are treated in a secondary combustion chamber. Primary treatment kiln temperature was maintained at 260 degree C for each test during the evaluation. The LTTD unit was evaluated for two sets of operating conditions: two levels of inlet soil total petroleum hydrocarbon concentrations and two feed rates (16,000 and 22,000 kg/h). Emissions from the LTTD unit were monitored continuously for volatile organics, moisture, and gas velocity. Results of the tests and emissions analyses are presented. Outlet soil hydrocarbon concentration requirements of 100 ppM were not exceeded during the evaluation. Air hydrocarbon emissions only exceeded 100-ppM limits under upset conditions, otherwise virturally no total hydrocarbon content was observed in the stack gas. 5 refs., 6 figs., 9 tabs

  10. Composite Materials for Low-Temperature Applications

    Science.gov (United States)

    2008-01-01

    Composite materials with improved thermal conductivity and good mechanical strength properties should allow for the design and construction of more thermally efficient components (such as pipes and valves) for use in fluid-processing systems. These materials should have wide application in any number of systems, including ground support equipment (GSE), lunar systems, and flight hardware that need reduced heat transfer. Researchers from the Polymer Science and Technology Laboratory and the Cryogenics Laboratory at Kennedy Space Center were able to develop a new series of composite materials that can meet NASA's needs for lightweight materials/composites for use in fluid systems and also expand the plastic-additive markets. With respect to thermal conductivity and physical properties, these materials are excellent alternatives to prior composite materials and can be used in the aerospace, automotive, military, electronics, food-packaging, and textile markets. One specific application of the polymeric composition is for use in tanks, pipes, valves, structural supports, and components for hot or cold fluid-processing systems where heat flow through materials is a problem to be avoided. These materials can also substitute for metals in cryogenic and other low-temperature applications. These organic/inorganic polymeric composite materials were invented with significant reduction in heat transfer properties. Decreases of 20 to 50 percent in thermal conductivity versus that of the unmodified polymer matrix were measured. These novel composite materials also maintain mechanical properties of the unmodified polymer matrix. These composite materials consist of an inorganic additive combined with a thermoplastic polymer material. The intrinsic, low thermal conductivity of the additive is imparted into the thermoplastic, resulting in a significant reduction in heat transfer over that of the base polymer itself, yet maintaining most of the polymer's original properties. Normal

  11. Oregon Low-Temperature-Resource Assessment Program. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Priest, G.R.; Black, G.L.; Woller, N.M.

    1981-01-01

    Numerous low-temperature hydrothermal systems are available for exploitation throughout the Cascades and eastern Oregon. All of these areas have heat flow significantly higher than crustal averages and many thermal aquifers. In northeastern Oregon, low temperature geothermal resources are controlled by regional stratigraphic aquifers of the Columbia River Basalt Group at shallow depths and possibly by faults at greater depths. In southeastern Oregon most hydrothermal systems are of higher temperature than those of northeastern Oregon and are controlled by high-angle fault zones and layered volcanic aquifers. The Cascades have very high heat flow but few large population centers. Direct use potential in the Cascades is therefore limited, except possibly in the cities of Oakridge and Ashland, where load may be great enough to stimulate development. Absence of large population centers also inhibits initial low temperature geothermal development in eastern Oregon. It may be that uses for the abundant low temperature geothermal resources of the state will have to be found which do not require large nearby population centers. One promising use is generation of electricity from freon-based biphase electrical generators. These generators will be installed on wells at Vale and Lakeview in the summer of 1982 to evaluate their potential use on geothermal waters with temperatures as low as 80/sup 0/C (176/sup 0/F).

  12. In situ heat treatment process utilizing a closed loop heating system

    Science.gov (United States)

    Vinegar, Harold J.; Nguyen, Scott Vinh

    2010-12-07

    Systems and methods for an in situ heat treatment process that utilizes a circulation system to heat one or more treatment areas are described herein. The circulation system may use a heated liquid heat transfer fluid that passes through piping in the formation to transfer heat to the formation. In some embodiments, the piping may be positioned in at least two of the wellbores.

  13. Utilization of low temperature geothermal water in traditional and advanced agricultural applications

    International Nuclear Information System (INIS)

    Rossi, L.; Pacciaroni, F.

    1992-01-01

    The locations of large amounts of low temperature geothermal sources (30 to 80 degrees C) have been identified in Italy and in many European countries; one of the most interesting utilization of these sources is greenhouse heating. Surplus investment in comparison with conventional heating systems is justified only by the application of low cost technologies for well completion, heating distribution and waste heat treatment. In the last few years, many efforts have been made in the development of these technologies and selection of more profitable crops. Since 1984, ENEA (Italian Agency for Energy, New Technologies and the Environment) has carried out experimental work in two geothermal stations located in Canino (VT) and in Gorgo di Latisana (UD). In these plants, a number of greenhouses enveloped with plastic film are provided with different heating systems; the combination of soil and forced air heating is preferred. Plastic pipes, buried in the soil, are used as soil heating for horticulture and fruit production. For plot plant cultivation, soil heating is obtained by plastic pipes half-buried in a concrete floor. Asparagus cultivation is carried out with buried pipes. No additional heating with conventional fuel is provided in any greenhouse. During these years, ENEA has developed heating and water distribution technologies: current industrial components are generally utilized. Moreover, ENEA has recently completed an advanced automatic control system able to control geothermal greenhouses, manage water distribution, save energy and optimize environmental conditions

  14. Utilization of low temperature geothermal water in traditional and advanced agricultural applications

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, L.; Pacciaroni, F.

    1992-12-31

    The locations of large amounts of low temperature geothermal sources (30 to 80 degrees C) have been identified in Italy and in many European countries; one of the most interesting utilization of these sources is greenhouse heating. Surplus investment in comparison with conventional heating systems is justified only by the application of low cost technologies for well completion, heating distribution and waste heat treatment. In the last few years, many efforts have been made in the development of these technologies and selection of more profitable crops. Since 1984, ENEA (Italian Agency for Energy, New Technologies and the Environment) has carried out experimental work in two geothermal stations located in Canino (VT) and in Gorgo di Latisana (UD). In these plants, a number of greenhouses enveloped with plastic film are provided with different heating systems; the combination of soil and forced air heating is preferred. Plastic pipes, buried in the soil, are used as soil heating for horticulture and fruit production. For plot plant cultivation, soil heating is obtained by plastic pipes half-buried in a concrete floor. Asparagus cultivation is carried out with buried pipes. No additional heating with conventional fuel is provided in any greenhouse. During these years, ENEA has developed heating and water distribution technologies: current industrial components are generally utilized. Moreover, ENEA has recently completed an advanced automatic control system able to control geothermal greenhouses, manage water distribution, save energy and optimize environmental conditions.

  15. Effect of heat treatment changes on swelling treatment of coal; Sekitan no bojun shori sayo ni oyobosu netsushori henka no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Satsuka, T.; Mashimo, K.; Wainai, T. [Nihon University, Tokyo (Japan). College of Science and Technology

    1996-10-28

    Discussions were given on effects of heat treatment at relatively low temperatures as a pretreatment for coal liquefaction on coal swelling and hydrogenolysis reaction. Taiheiyo coal was heated to 200{degree}C for one hour as a pretreatment. The attempted heating methods consisted of four steps of rapid heating (6.7{degree}C/min)quenching (20{degree}C/min), rapid heating/natural cooling (0.7{degree}C/min), heating (1.0{degree}C/min)/quenching, and heating/natural cooling. The swelling treatment was composed of adding methanol benzene into heat treated coal, and leaving it at room temperature for 24 hours. The hydrogenolysis was carried out by using a tetralin solvent and at an initial hydrogen pressure of 20 kg/cm{sup 2} and a temperature of 350{degree}C and for a time of one hour. Hydrogenolysis conversion in the heat treated coal was found lower than that of the original coal because of generation of liquefaction inactive components due to thermal polymerization. When the heat treated coal is swollen by using the solvent, gas yield from the hydrogenolysis reaction decreased due to gas suppression effect, and the conversion was lower than that of the original coal. Heat treatment suggests densification of the coal structure. Swollen coal shows no conspicuous difference in the heat treatment methods against the hydrogenolysis due to the swelling effect. 3 refs., 5 figs., 1 tab.

  16. Heat Treatment and Properties of Iron and Steel

    National Research Council Canada - National Science Library

    Digges, Thomas

    1966-01-01

    .... Chemical compositions, heat treatments, and some properties and uses are presented for structural steels, tool steels, stainless and heat-resisting steels, precipitation-hardenable stainless steels...

  17. Exploitation of low-temperature energy sources from cogeneration gas engines

    International Nuclear Information System (INIS)

    Caf, A.; Urbancl, D.; Trop, P.; Goricanec, D.

    2016-01-01

    This paper describes an original and innovative technical solution for exploiting low-temperature energy sources from cogeneration gas reciprocating engines installed within district heating systems. This solution is suitable for those systems in which the heat is generated by the use of reciprocating engines powered by gaseous fuel for combined heat and power production. This new technical solution utilizes low-temperature energy sources from a reciprocating gas engine which is used for a combined production of heat and power. During the operation of the cogeneration system low-temperature heat is released, which can be raised to as much as 85 °C with the use of a high-temperature heat-pump, thus enabling a high-temperature regime for heating commercial buildings, district heating or in industrial processes. In order to demonstrate the efficiency of utilizing low-temperature heat sources in the cogeneration system, an economic calculation is included which proves the effectiveness and rationality of integrating high-temperature heat-pumps into new or existing systems for combined heat and power production with reciprocating gas engines. - Highlights: • The use of low-temperature waste heat from the CHP is described. • Total energy efficiency of the CHP can be increased to more than 103.3%. • Low-temperature heat is exploited with high-temperature heat pump. • High-temperature heat pump allows temperature rise to up to 85 °C. • Exploitation of low-temperature waste heat increases the economics of the CHP.

  18. Low-Temperature Baseboard Heaters in Built Environments

    Energy Technology Data Exchange (ETDEWEB)

    Ploskic, Adnan

    2010-10-15

    The European Union has adopted a plan to decrease 20 % of total energy consumption through improved energy efficiency by 2020. One way of achieving this challenging goal may be to use efficient water-based heating systems supplied by heat pumps or other sustainable systems. The goal of this research was to analyze and improve the thermal performance of water-based baseboard heaters at low-temperature water supply. Both numerical (CFD) and analytical simulations were used to investigate the heat efficiency of the system. An additional objective of this work was to ensure that the indoor thermal comfort was satisfied in spaces served by such a low-temperature heating system. Analyses showed that it was fully possible to cover both transmission and ventilation heat losses using baseboard heaters supplied by 45 deg C water flow. The conventional baseboards, however, showed problems in suppressing the cold air down-flow created by 2.0 m high glazing and an outdoor temperature of -12 deg C. The draught discomfort at ankle level was slightly above the upper limit recommended by international and national standards. On the other hand, thermal baseboards with integrated ventilation air supply showed better ability to neutralize cold downdraught at the same height and conditions. Calculations also showed that the heat output from the integrated system with one ventilation inlet was approximately twice as high as that of the conventional one. The general conclusion from this work was that low temperature baseboards, especially with integrated ventilation air supply, are an efficient heating system and able to be combined with devices that utilize the low-quality sustainable energy sources such as heat pumps

  19. Analysis of Low-Temperature Utilization of Geothermal Resources

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Brian

    2015-06-30

    Full realization of the potential of what might be considered “low-grade” geothermal resources will require that we examine many more uses for the heat than traditional electricity generation. To demonstrate that geothermal energy truly has the potential to be a national energy source we will be designing, assessing, and evaluating innovative uses for geothermal-produced water such as hybrid biomass-geothermal cogeneration of electricity and district heating and efficiency improvements to the use of cellulosic biomass in addition to utilization of geothermal in district heating for community redevelopment projects. The objectives of this project were: 1) to perform a techno-economic analysis of the integration and utilization potential of low-temperature geothermal sources. Innovative uses of low-enthalpy geothermal water were designed and examined for their ability to offset fossil fuels and decrease CO2 emissions. 2) To perform process optimizations and economic analyses of processes that can utilize low-temperature geothermal fluids. These processes included electricity generation using biomass and district heating systems. 3) To scale up and generalize the results of three case study locations to develop a regionalized model of the utilization of low-temperature geothermal resources. A national-level, GIS-based, low-temperature geothermal resource supply model was developed and used to develop a series of national supply curves. We performed an in-depth analysis of the low-temperature geothermal resources that dominate the eastern half of the United States. The final products of this study include 17 publications, an updated version of the cost estimation software GEOPHIRES, and direct-use supply curves for low-temperature utilization of geothermal resources. The supply curves for direct use geothermal include utilization from known hydrothermal, undiscovered hydrothermal, and near-hydrothermal EGS resources and presented these results at the Stanford

  20. Poly-crystallinity of indium-tin-oxide films improved by using simultaneous ion beam and heat treatment of the plastic substrate

    International Nuclear Information System (INIS)

    Son, Phil Kook; Kim, Tae Hyung; Choi, Suk Won; Gwag, Jin Seog

    2012-01-01

    The combined treatment effects of an ion beam with directionality and heat of a low temperature on a plastic substrate was investigated as a method to increase the electrical conductivity of indium tinoxide (ITO) films deposited on plastic substrate surfaces at low temperatures. Polyethylene terephthalate (PET) surface treatment by using an ion beam at low temperature (120 .deg. C), which can be applied to plastic substrates, improves the conductivity of ITO films. X-ray diffraction indicates that ITO films deposited on PET surfaces treated simultaneously by using an ion beam and heat of a low temperature have an almost polycrystalline structure even though they have small amorphous party on. As a supplementary measurement, the contact angle showed that the polycrystalline structure was due to a self-assembly effect at the PET surfaces. Consequently, the electrical conductivity of an ITO film deposited by using the proposed technique is three times higher than that of an ITO film treated only with heat of low temperature due to the improved polycrystalline structure.

  1. Poly-crystallinity of indium-tin-oxide films improved by using simultaneous ion beam and heat treatment of the plastic substrate

    Science.gov (United States)

    Son, Phil Kook; Kim, Taehyung; Choi, Suk-Won; Gwag, Jin Seog

    2012-08-01

    The combined treatment effects of an ion beam with directionality and heat of a low temperature on a plastic substrate was investigated as a method to increase the electrical conductivity of indiumtin-oxide (ITO) films deposited on plastic substrate surfaces at low temperatures. Polyethylene terephthalate (PET) surface treatment by using an ion beam at low temperature (120 °C), which can be applied to plastic substrates, improves the conductivity of ITO films. X-ray diffraction indicates that ITO films deposited on PET surfaces treated simultaneously by using an ion beam and heat of a low temperature have an almost polycrystalline structure even though they have small amorphous party on. As a supplementary measurement, the contact angle showed that the polycrystalline structure was due to a self-assembly effect at the PET surfaces. Consequently, the electrical conductivity of an ITO film deposited by using the proposed technique is three times higher than that of an ITO film treated only with heat of low temperature due to the improved polycrystalline structure.

  2. Improved Low Temperature Performance of Supercapacitors

    Science.gov (United States)

    Brandon, Erik J.; West, William C.; Smart, Marshall C.; Gnanaraj, Joe

    2013-01-01

    Low temperature double-layer capacitor operation enabled by: - Base acetonitrile / TEATFB salt formulation - Addition of low melting point formates, esters and cyclic ethers center dot Key electrolyte design factors: - Volume of co-solvent - Concentration of salt center dot Capacity increased through higher capacity electrodes: - Zeolite templated carbons - Asymmetric cell designs center dot Continuing efforts - Improve asymmetric cell performance at low temperature - Cycle life testing Motivation center dot Benchmark performance of commercial cells center dot Approaches for designing low temperature systems - Symmetric cells (activated carbon electrodes) - Symmetric cells (zeolite templated carbon electrodes) - Asymmetric cells (lithium titanate/activated carbon electrodes) center dot Experimental results center dot Summary

  3. Fabrication techniques to eliminate postweld heat treatment

    International Nuclear Information System (INIS)

    Lochhead, J.C.

    1978-01-01

    Postweld heat treatments to reduce residual stresses (stress relief operations) have been a common practice in the pressure vessel industry for a large number of years. A suitable heat treatment operation can, in particular for low alloy steels, have additional beneficial effects, i.e. a reduction in peak hardness values in the heat-affected zone, an improvement in weld metal properties, and a lowering of the adverse effects of the welding process on the mechanical properties of the parent material adjacent to the weld metal. However, continuing studies in the field of brittle fracture, improved parent materials, and more sophisticated nondestructive testing techniques have led to the elimination of such a practice in ever-increasing thickness ranges and types of material. For instance, the recently issued BS 5500 compared with BS 1113 (1969) lifts the thickness limit requiring stress relief in certain circumstances from 19 to 35mm for C steels. With respect to materials the CEGB has stated that as a result of successful operational experience it will no longer be necessary to postweld heat treat butt welds in 2 1/4 Cr-1Mo tubes of certain dimensions. Despite this trend, over a period of years a number of instances have arisen where, because of some factor, postweld heat treatment, although perhaps desirable, is not possible. This Paper describes several such examples. It must be noted that the examples quoted consist of relatively important and major items. It has been necessary within the confines of this Paper to condense the reports. It is hoped that no significant factors have been omitted. (author)

  4. Technoeconomic Optimization of Waste Heat Driven Forward Osmosis for Flue Gas Desulfurization Wastewater Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Gingerich, Daniel B [Carnegie Mellon Univ., Pittsburgh, PA (United States); Bartholomew, Timothy V [Carnegie Mellon Univ., Pittsburgh, PA (United States); Mauter, Meagan S [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    2017-06-26

    With the Environmental Protection Agency’s recent Effluent Limitation Guidelines for Steam Electric Generators, power plants are having to install and operate new wastewater technologies. Many plants are evaluating desalination technologies as possible compliance options. However, the desalination technologies under review that can reduce wastewater volume or treat to a zero-liquid discharges standard have a significant energy penalty to the plant. Waste heat, available from the exhaust gas or cooling water from coal-fired power plants, offers an opportunity to drive wastewater treatment using thermal desalination technologies. One such technology is forward osmosis (FO). Forward osmosis utilizes an osmotic pressure gradient to passively pull water from a saline or wastewater stream across a semi-permeable membrane and into a more concentrated draw solution. This diluted draw solution is then fed into a distillation column, where the addition of low temperature waste heat can drive the separation to produce a reconcentrated draw solution and treated water for internal plant reuse. The use of low-temperature waste heat decouples water treatment from electricity production and eliminates the link between reducing water pollution and increasing air emissions from auxiliary electricity generation. In order to evaluate the feasibility of waste heat driven FO, we first build a model of an FO system for flue gas desulfurization (FGD) wastewater treatment at coal-fired power plants. This model includes the FO membrane module, the distillation column for draw solution recovery, and waste heat recovery from the exhaust gas. We then add a costing model to account for capital and operating costs of the forward osmosis system. We use this techno-economic model to optimize waste heat driven FO for the treatment of FGD wastewater. We apply this model to three case studies: the National Energy Technology Laboratory (NETL) 550 MW model coal fired power plant without carbon

  5. Thermodynamics of partially confined Fermi gases at low temperature

    International Nuclear Information System (INIS)

    Toms, David J

    2004-01-01

    We examine the behaviour of non-interacting Fermi gases at low temperature. If there is a confining potential present the thermodynamic behaviour is altered from the familiar results for the unconfined gas. The role of de Haas-van Alphen type oscillations that are a consequence of the confining potential is considered. Attention is concentrated on the behaviour of the chemical potential and the specific heat. Results are compared and contrasted with those for an unconfined and a totally confined gas

  6. Analysis of low-temperature tar fractions

    Energy Technology Data Exchange (ETDEWEB)

    Kikkawa, S; Yamada, F

    1952-01-01

    A preliminary comparative study was made on the applicability of the methods commonly used for the type analysis of petroleum products to the low-temperature tar fractions. The usability of chromatography was also studied.

  7. Low temperature plasma technology methods and applications

    CERN Document Server

    Chu, Paul K

    2013-01-01

    Written by a team of pioneering scientists from around the world, Low Temperature Plasma Technology: Methods and Applications brings together recent technological advances and research in the rapidly growing field of low temperature plasmas. The book provides a comprehensive overview of related phenomena such as plasma bullets, plasma penetration into biofilms, discharge-mode transition of atmospheric pressure plasmas, and self-organization of microdischarges. It describes relevant technology and diagnostics, including nanosecond pulsed discharge, cavity ringdown spectroscopy, and laser-induce

  8. Energy-efficient and cost-effective in-house substations bypass for improving thermal and DHW (domestic hot water) comfort in bathrooms in low-energy buildings supplied by low-temperature district heating

    DEFF Research Database (Denmark)

    Brand, Marek; Dalla Rosa, Alessandro; Svendsen, Svend

    2014-01-01

    temperature and additional cooling of bypass water by 3.9 °C, reducing the heat loss from the DH network by 13% and covering 40% of the heat used in the bathroom FH. The use of the bypass flow in bathroom FH is a cost-effective solution exploiting the heat that would otherwise be lost in the DH network......Using a bypass to redirect a small flow through the in-house DH (district heating) substation directly to the return pipe is a commonly used but energy-inefficient solution to keep the DH network “warm” during non-heating seasons. Instead, this water can be redirected to the bathroom FH (floor...... heating) to cool down further and thus reduce the heat lost from bypass operation while tempering the bathroom floor and guaranteeing fast provision of DHW (domestic hot water). We used the commercial software IDA-ICE to model a reference building where we implemented various solutions for controlling...

  9. Radiation detection at very low temperature. DRTBT 1991 Aussois - Course collection

    International Nuclear Information System (INIS)

    Salce, B.; Godfrin, H.; Dumoulin, L.; Garoche, Pierre; Pannetier, B.; Equer, B.; Hubert, PH.; Urbina, C.; Lamarre, J.M.; Brison, J.P.; Lesueur, D.; Bret, J.L.; Ayela, F.; Coron, N.; Gonzalez-Mestres, L.

    1991-12-01

    This publication gather several courses which propose or address: Thermal conduction, Kapitza resistance, Metal-insulator transition, Thermal properties and specific heat at low temperature, Thermometry, Low temperature superconductors, Defects due to irradiations in solids, Semiconducting detectors, Techniques of protection of a measurement assembly at low temperatures against perturbations, Noise reduction by impedance matching converter at low temperature, Low noise electronics and measurement, Low radio-activities, SQUID and electrometer, Results and expectations related to bolometers, Infrared and sub-millimetre radiation in astrophysics, Neutrinos, dark matter and heavy ions

  10. Minimizing material damage using low temperature irradiation

    International Nuclear Information System (INIS)

    Craven, E.; Hasanain, F.; Winters, M.

    2012-01-01

    Scientific advancements in healthcare driven both by technological breakthroughs and an aging and increasingly obese population have lead to a changing medical device market. Complex products and devices are being developed to meet the demands of leading edge medical procedures. Specialized materials in these medical devices, including pharmaceuticals and biologics as well as exotic polymers present a challenge for radiation sterilization as many of these components cannot withstand conventional irradiation methods. The irradiation of materials at dry ice temperatures has emerged as a technique that can be used to decrease the radiation sensitivity of materials. The purpose of this study is to examine the effect of low temperature irradiation on a variety of polymer materials, and over a range of temperatures from 0 °C down to −80 °C. The effectiveness of microbial kill is also investigated under each of these conditions. The results of the study show that the effect of low temperature irradiation is material dependent and can alter the balance between crosslinking and chain scission of the polymer. Low temperatures also increase the dose required to achieve an equivalent microbiological kill, therefore dose setting exercises must be performed under the environmental conditions of use. - Highlights: ► A study is performed to quantify low temperature irradiation effects on polymer materials and BIs. ► Low temperature irradiation alters the balance of cross-linking and chain scissoning in polymers. ► Low temperatures provide radioprotection for BIs. ► Benefits of low temperatures are application specific and must be considered when dose setting.

  11. Low temperature sintering of fluorapatite glass-ceramics

    Science.gov (United States)

    Denry, Isabelle; Holloway, Julie A.

    2014-01-01

    Fluorapatite glass-ceramics have been shown to be excellent candidates as scaffold materials for bone grafts, however, scaffold production by sintering is hindered by concurrent crystallization of the glass. Our goal was to investigate the effect of Ca/Al ratio on the sintering behavior of Nb-doped fluorapatite-based glasses in the SiO2-Al2O3-P2O5-MgO-Na2O-K2O-CaO-CaF2 system. Glass compositions with Ca/Al ratio of 1 (A), 2 (B), 4 (C) and 19 (D) were prepared by twice melting at 1525°C for 3h. Glasses were either cast as cylindrical ingots or ground into powders. Disc-shaped specimens were prepared by either sectioning from the ingots or powder-compacting in a mold, followed by heat treatment at temperatures ranging between 700 and 1050°C for 1h. The density was measured on both sintered specimens and heat treated discs as controls. The degree of sintering was determined from these measurements. XRD showed that fluorapatite crystallized in all glass-ceramics. A high degree of sintering was achieved at 775°C for glass-ceramic D (98.99±0.04%), and 900°C for glass-ceramic C (91.31±0.10). Glass-ceramics A or B were only partially sintered at 1000°C (63.6±0.8% and 74.1±1.5%, respectively). SEM revealed a unique microstructure of micron-sized spherulitic fluorapatite crystals in glass-ceramics C and D. Increasing the Ca/Al ratio promoted low temperature sintering of fluorapatite glass-ceramics, which are traditionally difficult to sinter. PMID:24252652

  12. Low temperature sintering of fluorapatite glass-ceramics.

    Science.gov (United States)

    Denry, Isabelle; Holloway, Julie A

    2014-02-01

    Fluorapatite glass-ceramics have been shown to be excellent candidates as scaffold materials for bone grafts, however, scaffold production by sintering is hindered by concurrent crystallization of the glass. Objective, our goal was to investigate the effect of Ca/Al ratio on the sintering behavior of Nb-doped fluorapatite-based glasses in the SiO2-Al2O3-P2O5-MgO-Na2O-K2O-CaO-CaF2 system. Methods, glass compositions with Ca/Al ratio of 1 (A), 2 (B), 4 (C) and 19 (D) were prepared by twice melting at 1525°C for 3h. Glasses were either cast as cylindrical ingots or ground into powders. Disk-shaped specimens were prepared by either sectioning from the ingots or powder-compacting in a mold, followed by heat treatment at temperatures ranging between 700 and 1050°C for 1h. The density was measured on both sintered specimens and heat treated discs as controls. The degree of sintering was determined from these measurements. Results and Significance XRD showed that fluorapatite crystallized in all glass-ceramics. A high degree of sintering was achieved at 775°C for glass-ceramic D (98.99±0.04%), and 900°C for glass-ceramic C (91.31±0.10). Glass-ceramics A or B were only partially sintered at 1000°C (63.6±0.8% and 74.1±1.5%, respectively). SEM revealed a unique microstructure of micron-sized spherulitic fluorapatite crystals in glass-ceramics C and D. Increasing the Ca/Al ratio promoted low temperature sintering of fluorapatite glass-ceramics, which are traditionally difficult to sinter. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  13. Induction heat treatment of laser welds

    DEFF Research Database (Denmark)

    Bagger, Claus; Olsen, Flemming Ove; Sørensen, Joakim Ilsing

    2003-01-01

    of an induction coil. A number of systematic laboratory tests were then performed in order to study the effects of the coil on bead-on-plate laser welded samples. In these tests, important parameters such as coil current and distance between coil and sample were varied. Temperature measurements were made...... the laser beam as close as possible. After welding, the samples were quality assessed according to ISO 13.919-1 and tested for hardness. The metallurgical phases are analysed and briefly described. A comparison between purely laser welded samples and induction heat-treated laser welded samples is made......In this paper, a new approach based on induction heat-treatment of flat laser welded sheets is presented. With this new concept, the ductility of high strength steels GA260 with a thickness of 1.8 mm and CMn with a thickness of 2.13 mm is believed to be improved by prolonging the cooling time from...

  14. Influence of heat treatment on the strength and fracture toughness of 7N01 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bo [School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan (China); Wang, Xiaomin, E-mail: xmwang991011@163.com [School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan (China); Chen, Hui; Hu, Jie [School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan (China); Huang, Cui [School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan (China); Gou, Guoqing [School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan (China)

    2016-09-05

    7N01 aluminum (Al) alloys are treated by five heat treatment methods as peak aging (T6), over aging (T74), high temperature and subsequently low temperature aging (HLA), retrogression and reaging (RRA) and double retrogression and reaging (DRRA). The strength and fracture toughness of the five samples are tested, and the microstructures are investigated by optical microscopy (OM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The results show that 7N01 Al-alloy treated at T6 condition has high strength but low fracture toughness. Compared with T6 treatment, T74 and HLA treatments increase the fracture toughness by 67% and 90% respectively, while the strength decrease by 9% and 17%. RRA process is a proper treatment method for 7N01 which improves the fracture toughness without sacrificing strength. The fracture toughness of DRRA treated alloy is much lower than that of RRA. Quantitative analysis through TEM images shows that the heat treatment affects the mechanical properties of 7N01 Al-alloy highly through changing the precipitates in grains and on grain boundaries, which can be explained by the coherency strengthening mechanism and Orowan mechanism. - Highlights: • Five heat treatments which can change the properties of 7N01 Al alloy were designed. • Quantitative analysis of precipitates was employed to study the mechanism. • RRA treatment can make proper strength/toughness property balances for 7N01 Al alloy.

  15. Influence of heat treatment on the strength and fracture toughness of 7N01 aluminum alloy

    International Nuclear Information System (INIS)

    Li, Bo; Wang, Xiaomin; Chen, Hui; Hu, Jie; Huang, Cui; Gou, Guoqing

    2016-01-01

    7N01 aluminum (Al) alloys are treated by five heat treatment methods as peak aging (T6), over aging (T74), high temperature and subsequently low temperature aging (HLA), retrogression and reaging (RRA) and double retrogression and reaging (DRRA). The strength and fracture toughness of the five samples are tested, and the microstructures are investigated by optical microscopy (OM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The results show that 7N01 Al-alloy treated at T6 condition has high strength but low fracture toughness. Compared with T6 treatment, T74 and HLA treatments increase the fracture toughness by 67% and 90% respectively, while the strength decrease by 9% and 17%. RRA process is a proper treatment method for 7N01 which improves the fracture toughness without sacrificing strength. The fracture toughness of DRRA treated alloy is much lower than that of RRA. Quantitative analysis through TEM images shows that the heat treatment affects the mechanical properties of 7N01 Al-alloy highly through changing the precipitates in grains and on grain boundaries, which can be explained by the coherency strengthening mechanism and Orowan mechanism. - Highlights: • Five heat treatments which can change the properties of 7N01 Al alloy were designed. • Quantitative analysis of precipitates was employed to study the mechanism. • RRA treatment can make proper strength/toughness property balances for 7N01 Al alloy.

  16. 49 CFR 179.200-11 - Postweld heat treatment.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Postweld heat treatment. 179.200-11 Section 179.200-11 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS... Postweld heat treatment. When specified in § 179.201-1, after welding is complete, postweld heat treatment...

  17. The development of low-temperature calorimeter on the Peltier elements

    Science.gov (United States)

    Baturevich, Tatyana; Tyagunin, Anatoly

    2017-09-01

    The article is devoted to the design of low-temperature calorimeter on the Peltier elements. This calorimeter can be used to study the temperature dependence of the specific heat capacity of different substances.

  18. Low temperature chemical processing of graphite-clad nuclear fuels

    Science.gov (United States)

    Pierce, Robert A.

    2017-10-17

    A reduced-temperature method for treatment of a fuel element is described. The method includes molten salt treatment of a fuel element with a nitrate salt. The nitrate salt can oxidize the outer graphite matrix of a fuel element. The method can also include reduced temperature degradation of the carbide layer of a fuel element and low temperature solubilization of the fuel in a kernel of a fuel element.

  19. Kinetics and spectroscopy of low temperature plasmas

    CERN Document Server

    Loureiro, Jorge

    2016-01-01

    This is a comprehensive textbook designed for graduate and advanced undergraduate students. Both authors rely on more than 20 years of teaching experience in renowned Physics Engineering courses to write this book addressing the students’ needs. Kinetics and Spectroscopy of Low Temperature Plasmas derives in a full self-consistent way the electron kinetic theory used to describe low temperature plasmas created in the laboratory with an electrical discharge, and presents the main optical spectroscopic diagnostics used to characterize such plasmas. The chapters with the theoretical contents make use of a deductive approach in which the electron kinetic theory applied to plasmas with basis on the electron Boltzmann equation is derived from the basic concepts of Statistical and Plasma Physics. On the other hand, the main optical spectroscopy diagnostics used to characterize experimentally such plasmas are presented and justified from the point of view of the Atomic and Molecular Physics. Low temperature plasmas...

  20. On the Interpretation of Low Temperature Calorimetry Data

    DEFF Research Database (Denmark)

    Kjeldsen, Ane Mette; Geiker, Mette Rica

    2008-01-01

    The effect of selected factors and phenomena on Low Temperature Calorimetry (LTC) results has been investigated, in order to determine the possibilities and limitations of using LTC for characterisation of the porosity of cement-based materials. LTC was carried out on a model material with mono......-sized pores of approximately 14 nm saturated with either distilled water or a sodium chloride solution, as well as on water, the salt solution, and an artificial pore solution, alone. It was found that supercooling is unavoidable during the liquid-solid phase transition, and that even at low temperature...... to limit transport of liquid, whereas heating should be undertaken at a low rate to limit the effect of non-equilibrium....

  1. Low temperature monitoring system for subsurface barriers

    Science.gov (United States)

    Vinegar, Harold J [Bellaire, TX; McKinzie, II Billy John [Houston, TX

    2009-08-18

    A system for monitoring temperature of a subsurface low temperature zone is described. The system includes a plurality of freeze wells configured to form the low temperature zone, one or more lasers, and a fiber optic cable coupled to at least one laser. A portion of the fiber optic cable is positioned in at least one freeze well. At least one laser is configured to transmit light pulses into a first end of the fiber optic cable. An analyzer is coupled to the fiber optic cable. The analyzer is configured to receive return signals from the light pulses.

  2. Materials for low-temperature fuel cells

    CERN Document Server

    Ladewig, Bradley; Yan, Yushan; Lu, Max

    2014-01-01

    There are a large number of books available on fuel cells; however, the majority are on specific types of fuel cells such as solid oxide fuel cells, proton exchange membrane fuel cells, or on specific technical aspects of fuel cells, e.g., the system or stack engineering. Thus, there is a need for a book focused on materials requirements in fuel cells. Key Materials in Low-Temperature Fuel Cells is a concise source of the most important and key materials and catalysts in low-temperature fuel cells. A related book will cover key materials in high-temperature fuel cells. The two books form part

  3. Low-temperature carbonization plant for lignite

    Energy Technology Data Exchange (ETDEWEB)

    Shiotsuki, Y

    1949-01-01

    The design and operational data of a low-temperature carbonization plant for Japanese lignite are described. The retort had a vertical cylinder with a capacity of about 10 tons per day. By continuous operation, in which a part of the gas produced was circulated and burned in the lignite zone, about 40 percent semicoke and 3 to 4 percent tar were obtained. From the tar the following products were separated: Low-temperature carbonization cresol, 18.3; motor fuel, 1.00; solvent, 9.97; cresol for medical uses, 11.85; and creosote oil, 32 percent.

  4. Anomalous thermal property behaviour of uranium at low temperatures

    International Nuclear Information System (INIS)

    Sandenaw, T.A.

    1975-01-01

    Low temperature heat capacity curves are presented for polycrystalline 235 U and 238 U metals in different microstructural states and of different purities. Thermal conductivity versus temperature curves are shown for low-purity, polycrystalline 238 U in the temperature range between approximately 80 and 373 0 K for metal having undergone varied fabrication procedures. Published information suggests that there will be no structural modification in very pure uranium below room temperature. The influence of impurities on low temperature transitions may be through their effects on dislocation formation. Thermal conductivity and heat capacity runs started at approximately 80 0 K, after holding specimens at the temperature of boiling liquid nitrogen, do not give results which match up with runs started below 36 to 43 0 K. Result of measurements started at approximately 80 0 K indicate that an ordering mechanism is predominating, with microstructure rather than purity being the important factor. This can be explained if ordering at approximately 80 0 K is through lattice imperfections remaining from prior specimen processing. The drop off in heat capacity appearing above 36 0 K in the C/sub p/ versus T curves of 235 U and 238 U suggest the possibility of: (1) heat evolution from a developing antiphase structure or (2) heat evolution similar to that noted with a quenched martensite. Physical property changes in 238 U at 250 to 270 0 K and at 325 to 350 0 K seem to be related to the heat evolution which starts at 36 0 K during adiabatic heat capacity measurements. The data from heat capacity and thermal conductivity measurements are analyzed to help explain the significance of the sometimes very slight physical property changes observed at 36 to 43, approximately 80, 250 to 270 and 325 to 350 0 K in uranium metal. (U.S.)

  5. Viscose liquid heat treatment using plate scraper heat exchanger

    Directory of Open Access Journals (Sweden)

    K. A. Rashkin

    2012-01-01

    Full Text Available The current work analyzes the use of different types of heat exchangers, depending on the technology of production. It is taken the detail analysis of the ways of applicability of various types of heat exchangers, depending on the viscosity of the processed product. It is posed the problem of the analytical determination of the required area of heat exchange with the use of differential equations of heat transfer in a moving liquid media, written in cylindrical coordinates, for symmetrical temperature distribution, without taking in account the energy dissipation.

  6. Effect of cold work on low-temperature sensitization behaviour of austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Kain, V. E-mail: vivkain@apsara.barc.ernet.in; Chandra, K.; Adhe, K.N.; De, P.K

    2004-09-01

    The effects of cold work and low-temperature sensitization heat treatment of non-sensitized austenitic stainless steels have been investigated and related to the cracking in nuclear power reactors. Types 304, 304L and 304LN developed martensite after 15% cold working. Heat treatment of these cold worked steels at 500 deg. C led to sensitization of grain boundaries and the matrix and a desensitization effect was seen in 11 days due to fast diffusion rate of chromium in martensite. Types 316L and 316LN did not develop martensite upon cold rolling due to its chemical composition suppressing the martensite transformation (due to deformation) temperature, hence these were not sensitized at 500 deg. C. The sensitization of the martensite phase was always accompanied by a hump in the reactivation current peak in the double loop electrochemical potentiokinetic reactivation test, thus providing a test to detect such sensitization. It was shown that bending does not produce martensite and therefore, is a better method to simulate weld heat affected zone. Bending and heating at 500 deg. C for 11 days led to fresh precipitation due to increased retained strain and desensitization of 304LN due to faster diffusion rate of chromium along dislocations. The as received or solution annealed 304 and 304LN with 0.15% nitrogen showed increased sensitization after heat treatment at 500 deg. C, indicating the presence of carbides/nitrides.

  7. Low temperature thermophysical properties of lunar soil

    Science.gov (United States)

    Cremers, C. J.

    1973-01-01

    The thermal conductivity and thermal diffusivity of lunar fines samples from the Apollo 11 and Apollo 12 missions, determined at low temperatures as a function of temperature and various densities, are reviewed. It is shown that the thermal conductivity of lunar soil is nearly the same as that of terrestrial basaltic rock under the same temperature and pressure conditions.

  8. Neutrinos, dark matter and low temperature detectors

    International Nuclear Information System (INIS)

    Gonzalez-Mestres, L.; Perret-Gallix, D.

    1988-01-01

    The present status of cryogenic detector developments for particle physics is discussed, with emphasis on applications at the cross-disciplinary frontier between particle physics and astrophysics, where low temperature devices appear to be particularly well suited. The overwiew of results is completed by a sketch of new ideas and possible ways for further improvements. Neutrino role importance is particularly shown

  9. Low Temperature Cure Powder Coatings (LTCPC)

    Science.gov (United States)

    2010-10-01

    Dr. Glen Merfeld, General Electric Global Research evaluated and optimized the formulation, and cure and performance parameters of candidate LTCPC...Unacceptable test result = Marginal test result = Acceptable test result 80 therefore suffer from brittleness at extremely low temperatures. NASA’s

  10. Industrial Applications of Low Temperature Plasmas

    International Nuclear Information System (INIS)

    Bardsley, J N

    2001-01-01

    The use of low temperature plasmas in industry is illustrated by the discussion of four applications, to lighting, displays, semiconductor manufacturing and pollution control. The type of plasma required for each application is described and typical materials are identified. The need to understand radical formation, ionization and metastable excitation within the discharge and the importance of surface reactions are stressed

  11. Low temperature anodic bonding to silicon nitride

    DEFF Research Database (Denmark)

    Weichel, Steen; Reus, Roger De; Bouaidat, Salim

    2000-01-01

    Low-temperature anodic bonding to stoichiometric silicon nitride surfaces has been performed in the temperature range from 3508C to 4008C. It is shown that the bonding is improved considerably if the nitride surfaces are either oxidized or exposed to an oxygen plasma prior to the bonding. Both bu...

  12. Arc generators of low-temperature plasma

    International Nuclear Information System (INIS)

    Krolikowski, Cz.; Niewiedzial, R.; Siwiec, J.

    1979-01-01

    This paper is a review of works concerning investigation and use of low-temperature plasma in arc plasma generators made in Electric Power Institute of PP. There are discussed: analytical approach to a problem of volt-current and operational characteristics of DC arc plasma generators, determination of limits of their stable work and possibilities of their use to technological aims. (author)

  13. Low-temperature heat capacity and thermodynamic properties of [Re2(Ile)4(H2O)8](ClO4)6 (Re=Nd, Er, Ile=isoleucine)

    International Nuclear Information System (INIS)

    Lan Xiaozheng; Tan Zhicheng; Liu Beiping; Nan Zhaodong; Sun Lixian; Xu Fen

    2003-01-01

    The heat capacities of two kinds of rare-earth element solid complexes with isoleucine [Re 2 (Ile) 4 (H 2 O) 8 ](ClO 4 ) 6 (where Re=Nd, Er, and Ile=isoleucine) have been measured by an automatic adiabatic calorimeter in the temperature range from 80 to 370 K. Two solid-solid phase transitions were found from the C p curve of Nd formed complex in the range of 165-175 K with a peak temperature of 167.88 K and in the range of 195-210 K with a peak temperature of 202.13 K. The corresponding molar enthalpies of these phase transitions were determined to be 404.61 J mol -1 and 2.955 kJ mol -1 , respectively. One solid-solid phase transition was found for the Er formed complex in the range of 190-205 K with a peak temperature of 193.42 K. The corresponding molar enthalpy of this transition was 14.11 kJ mol -1 . Smooth heat capacities and thermodynamic functions relative to the standard state (298.15 K), H T -H 298.15 , S T -S 298.15 and -[G T -G 298.15 ], of the two compounds, were calculated on basis of experimental heat capacity data. Possible mechanisms of thermal decompositions for the pair of compounds were suggested according to the thermogravimetric (TG) analysis

  14. Mortality of insect life stages during simulated heat treatment

    Science.gov (United States)

    . Heat treatment for insect disinfestation uses elevated air temperatures that are lethal to stored-product insects. Heat treatment has been demonstrated in our research to offer a reduced-risk alternative to fumigation or residual pesticide use in empty bins. Heat is also compatible with organic gr...

  15. Efficacy of heat treatment for disinfestation of concrete grain silos

    Science.gov (United States)

    Field experiments were conducted in 2007 and 2008 to evaluate heat treatment for disinfestations of empty concrete elevator silos. A Mobile Heat Treatment Unit was used to introduce heat into silos to attain target conditions of 50°C for at least 6 h. Ventilated plastic containers with a capacity of...

  16. Low-temperature heat capacity and thermodynamic properties of [Re{sub 2}(Ile){sub 4}(H{sub 2}O){sub 8}](ClO{sub 4}){sub 6} (Re=Nd, Er, Ile=isoleucine)

    Energy Technology Data Exchange (ETDEWEB)

    Lan Xiaozheng; Tan Zhicheng; Liu Beiping; Nan Zhaodong; Sun Lixian; Xu Fen

    2003-06-03

    The heat capacities of two kinds of rare-earth element solid complexes with isoleucine [Re{sub 2}(Ile){sub 4}(H{sub 2}O){sub 8}](ClO{sub 4}){sub 6} (where Re=Nd, Er, and Ile=isoleucine) have been measured by an automatic adiabatic calorimeter in the temperature range from 80 to 370 K. Two solid-solid phase transitions were found from the C{sub p} curve of Nd formed complex in the range of 165-175 K with a peak temperature of 167.88 K and in the range of 195-210 K with a peak temperature of 202.13 K. The corresponding molar enthalpies of these phase transitions were determined to be 404.61 J mol{sup -1} and 2.955 kJ mol{sup -1}, respectively. One solid-solid phase transition was found for the Er formed complex in the range of 190-205 K with a peak temperature of 193.42 K. The corresponding molar enthalpy of this transition was 14.11 kJ mol{sup -1}. Smooth heat capacities and thermodynamic functions relative to the standard state (298.15 K), H{sub T}-H{sub 298.15}, S{sub T}-S{sub 298.15} and -[G{sub T}-G{sub 298.15}], of the two compounds, were calculated on basis of experimental heat capacity data. Possible mechanisms of thermal decompositions for the pair of compounds were suggested according to the thermogravimetric (TG) analysis.

  17. Low temperature radiation embrittlement for reactor vessel steels

    International Nuclear Information System (INIS)

    Ginding, I.A.; Chirkina, L.A.

    1978-01-01

    General conceptions of cold brittleness of bcc metals are in a review. Considered are experimental data and theoretical representations about the effect of irradiation conditions, chemical composition, phase and structural constitutions, grain size, mechanical and thermomechanical treatments on low-temperature irradiation embrittlement of reactor vessel steels. Presented are the methods for increasing radiation stability of metals (carbon and Cr-Mo steels) used in manufacturing reactor vessels

  18. Determination of magnetic characteristics of nanoparticles by low-temperature calorimetry methods

    Energy Technology Data Exchange (ETDEWEB)

    Ugulava, A.; Toklikishvili, Z. [Department of Physics, I.Javakhishvili Tbilisi State University,I.Chavchavadze av. 3, 0179 Tbilisi, Georgia (United States); Chkhaidze, S., E-mail: simon.chkhaidze@tsu.ge [Department of Physics, I.Javakhishvili Tbilisi State University,I.Chavchavadze av. 3, 0179 Tbilisi, Georgia (United States); Kekutia, Sh. [V. Chavchanidze Institute of Cybernetics, at the Technical State University, S. Euli str. 5, 0186 Tbilisi, Georgia (United States)

    2017-05-15

    At low temperatures, the heat capacity of a superparamagnetic “ideal gas” determined by magnetic degrees of freedom can greatly exceed the lattice heat capacity. It is shown that in the presence of an external magnetic field, the temperature dependence of the magnetic part of the heat capacity has two maxima. The relations between the temperature at which these maxima are achieved, the magnetic moment of the nanoparticles and the magnetic anisotropy constant have been obtained. Measuring the heat capacity maxima temperatures by low-temperature calorimetry methods and using the obtained relations, we can obtain the numerical values both of the magnetic moment of nanoparticles and the magnetic anisotropy constants.

  19. Analysis of optimal design of low temperature economizer

    Science.gov (United States)

    Song, J. H.; Wang, S.

    2017-11-01

    This paper has studied the Off-design characteristic of low temperature economizer system based on thermodynamics analysis. Based on the data from one 1000 MW coal-fired unit, two modes of operation are contrasted and analyzed. One is to fix exhaust gas temperature and the other one is to take into account both of the average temperature difference and the exhaust gas temperature. Meanwhile, the cause of energy saving effect change is explored. Result shows that: in mode 1, the amount of decrease in coal consumption reduces from 1.11 g/kWh (under full load) to 0.54 g/kWh (under half load), and in mode 2, when the load decreases from 90% to 50%, the decrease in coal consumption reduces from 1.29 g/kWh to 0.84 g/kWh. From the result, under high load, the energy saving effect is superior, and under lower work load, energy saving effect declines rapidly when load is reduced. When load changes, the temperature difference of heat transfer, gas flow, the flue gas heat rejection and the waste heat recovery change. The energy saving effect corresponding changes result in that the energy saving effect under high load is superior and more stable. However, rational adjustment to the temperature of outlet gas can alleviate the decline of the energy saving effect under low load. The result provides theoretical analysis data for the optimal design and operation of low temperature economizer system of power plant.

  20. Analysis of Low Temperature Organic Rankine Cycles for Solar Applications

    Science.gov (United States)

    Li, Yunfei

    The present work focuses on Organic Rankine Cycle (ORC) systems and their application to low temperature waste heat recovery, combined heat and power as well as off-grid solar power generation applications. As CO_2 issues come to the fore front and fossil fuels become more expensive, interest in low grade heat recovery has grown dramatically in the past few years. Solar energy, as a clean, renewable, pollution-free and sustainable energy has great potential for the use of ORC systems. Several ORC solutions have been proposed to generate electricity from low temperature sources. The ORC systems discussed here can be applied to fields such as solar thermal, biological waste heat, engine exhaust gases, small-scale cogeneration, domestic boilers, etc. The current work presents a thermodynamic and economic analysis for the use of ORC systems to convert solar energy or low exergy energy to generate electrical power. The organic working fluids investigated here were selected to investigate the effect of the fluid saturation temperature on the performance of ORCs. The working fluids under investigation are R113, R245fa, R123, with boiling points between 40°C and 200°C at pressures from 10 kPa to 10 MPa. Ambient temperature air at 20oC to 30oC is utilized as cooling resource, and allowing for a temperature difference 10°C for effective heat transfer. Consequently, the working fluids are condensed at 40°C. A combined first- and second-law analysis is performed by varying some system independent parameters at various reference temperatures. The present work shows that ORC systems can be viable and economical for the applications such as waste heat use and off-grid power generation even though they are likely to be more expensive than grid power.

  1. Fabrication of Nb{sub 3}Al superconductor by the optimized mechanical alloying method with low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y., E-mail: yongzhang@swjtu.cn [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, and Superconductivity and New Energy R& D Center, Southwest Jiaotong University, Chengdu 610031 (China); Lin, W.J.; Xu, L.Y.; Yang, D.W.; Chen, Y.L. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, and Superconductivity and New Energy R& D Center, Southwest Jiaotong University, Chengdu 610031 (China); Li, P.Y.; Pan, X.F.; Yan, G. [Western Superconducting Technoligies Co., Ltd., Xi' an 710018 (China); Zhao, Y., E-mail: yzhao@home.swjtu.edu.cn [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, and Superconductivity and New Energy R& D Center, Southwest Jiaotong University, Chengdu 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney 2052 NSW (Australia)

    2016-11-15

    Highlights: • Due to a much better strain tolerance than Nb{sub 3}Sn, Nb{sub 3}Al has been considered as an excellent candidate for making high field magnets. At present, the Nb{sub 3}Al superconducting wires were prepared mainly by the Jelly-roll method combined with a rapid heating and quenching (RHQ) heat treatment at around 2000 °C. In this study, Nb{sub 3}Al superconductor with T{sub c} of 15.6 K is directly prepared with a mechanical alloying method followed by a low temperature annealing at 800 to 900 °C. Our results hint the possibility that Nb{sub 3}Al superconducting wire with high performance can be prepared below the melting point of Cu (1080 °C) by a conventional powder in tube (PIT) method, thus effectively avoiding high temperature heat treatment and RHQ device. - Abstract: Mechanical alloying was used to synthesize Nb{sub 3}Al superconductor successfully, and the process was optimization under various preparation conditions. In the current study, Nb{sub 3}Al superconductor with T{sub c} of 15.6 K was directly prepared from high quality Nb (Al) solid solution by mechanical alloying method and heat treatment at a low temperature of 800 to 900 °C. The results showed that Nb{sub 3}Al superconducting wire with high performance could be prepared after heat treatment below the melting point of Cu (1080°C) and using Nb (Al) solid solution and conventional powder in tube (PIT) method, thus effectively avoiding ultra-high temperature heat treatment and special rapid heating and quenching(RHQ) device.

  2. Design and Modelling of Small Scale Low Temperature Power Cycles

    DEFF Research Database (Denmark)

    Wronski, Jorrit

    he work presented in this report contributes to the state of the art within design and modelling of small scale low temperature power cycles. The study is divided into three main parts: (i) fluid property evaluation, (ii) expansion device investigations and (iii) heat exchanger performance......-oriented Modelica code and was included in the thermo Cycle framework for small scale ORC systems. Special attention was paid to the valve system and a control method for variable expansion ratios was introduced based on a cogeneration scenario. Admission control based on evaporator and condenser conditions...

  3. Low temperature catalytic combustion of natural gas - hydrogen - air mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Newson, E; Roth, F von; Hottinger, P; Truong, T B [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The low temperature catalytic combustion of natural gas - air mixtures would allow the development of no-NO{sub x} burners for heating and power applications. Using commercially available catalysts, the room temperature ignition of methane-propane-air mixtures has been shown in laboratory reactors with combustion efficiencies over 95% and maximum temperatures less than 700{sup o}C. After a 500 hour stability test, severe deactivation of both methane and propane oxidation functions was observed. In cooperation with industrial partners, scaleup to 3 kW is being investigated together with startup dynamics and catalyst stability. (author) 3 figs., 3 refs.

  4. Low Temperature Geothermal Resource Assessment for Membrane Distillation Desalination in the United States: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Akar, Sertac; Turchi, Craig

    2016-10-01

    Substantial drought and declines in potable groundwater in the United States over the last decade has increased the demand for fresh water. Desalination of saline water such as brackish surface or groundwater, seawater, brines co-produced from oil and gas operations, industrial wastewater, blow-down water from power plant cooling towers, and agriculture drainage water can reduce the volume of water that requires disposal while providing a source of high-quality fresh water for industrial or commercial use. Membrane distillation (MD) is a developing technology that uses low-temperature thermal energy for desalination. Geothermal heat can be an ideal thermal-energy source for MD desalination technology, with a target range of $1/m3 to $2/m3 for desalinated water depending on the cost of heat. Three different cases were analyzed to estimate levelized cost of heat (LCOH) for integration of MD desalination technology with low-grade geothermal heat: (1) residual heat from injection brine at a geothermal power plant, (2) heat from existing underutilized low-temperature wells, and (3) drilling new wells for low-temperature resources. The Central and Western United States have important low-temperature (<90 degrees C) geothermal resource potential with wide geographic distribution, but these resources are highly underutilized because they are inefficient for power production. According to the USGS, there are 1,075 identified low temperature hydrothermal systems, 55 low temperature sedimentary systems and 248 identified medium to high temperature geothermal systems in the United States. The estimated total beneficial heat potential from identified low temperature hydrothermal geothermal systems and residual beneficial heat from medium to high temperature systems is estimated as 36,300 MWth, which could theoretically produce 1.4 to 7 million m3/day of potable water, depending on desalination efficiency.

  5. Low Temperature Geothermal Resource Assessment for Membrane Distillation Desalination in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Akar, Sertac; Turchi, Craig

    2017-05-01

    Substantial drought and declines in potable groundwater in the United States over the last decade has increased the demand for fresh water. Desalination of saline water such as brackish surface or groundwater, seawater, brines co-produced from oil and gas operations, industrial wastewater, blow-down water from power plant cooling towers, and agriculture drainage water can reduce the volume of water that requires disposal while providing a source of high-quality fresh water for industrial or commercial use. Membrane distillation (MD) is a developing technology that uses low-temperature thermal energy for desalination. Geothermal heat can be an ideal thermal-energy source for MD desalination technology, with a target range of $1/m3 to $2/m3 for desalinated water depending on the cost of heat. Three different cases were analyzed to estimate levelized cost of heat (LCOH) for integration of MD desalination technology with low-grade geothermal heat: (1) residual heat from injection brine at a geothermal power plant, (2) heat from existing underutilized low-temperature wells, and (3) drilling new wells for low-temperature resources. The Central and Western United States have important low-temperature (<90 degrees C) geothermal resource potential with wide geographic distribution, but these resources are highly underutilized because they are inefficient for power production. According to the USGS, there are 1,075 identified low temperature hydrothermal systems, 55 low temperature sedimentary systems and 248 identified medium to high temperature geothermal systems in the United States. The estimated total beneficial heat potential from identified low temperature hydrothermal geothermal systems and residual beneficial heat from medium to high temperature systems is estimated as 36,300 MWth, which could theoretically produce 1.4 to 7 million m3/day of potable water, depending on desalination efficiency.

  6. Manufacturing Demonstration Facility: Low Temperature Materials Synthesis

    International Nuclear Information System (INIS)

    Graham, David E.; Moon, Ji-Won; Armstrong, Beth L.; Datskos, Panos G.; Duty, Chad E.; Gresback, Ryan; Ivanov, Ilia N.; Jacobs, Christopher B.; Jellison, Gerald Earle; Jang, Gyoung Gug; Joshi, Pooran C.; Jung, Hyunsung; Meyer, Harry M.; Phelps, Tommy

    2015-01-01

    The Manufacturing Demonstration Facility (MDF) low temperature materials synthesis project was established to demonstrate a scalable and sustainable process to produce nanoparticles (NPs) for advanced manufacturing. Previous methods to chemically synthesize NPs typically required expensive, high-purity inorganic chemical reagents, organic solvents and high temperatures. These processes were typically applied at small laboratory scales at yields sufficient for NP characterization, but insufficient to support roll-to-roll processing efforts or device fabrication. The new NanoFermentation processes described here operated at a low temperature (~60 C) in low-cost, aqueous media using bacteria that produce extracellular NPs with controlled size and elemental stoichiometry. Up-scaling activities successfully demonstrated high NP yields and quality in a 900-L pilot-scale reactor, establishing this NanoFermentation process as a competitive biomanufacturing strategy to produce NPs for advanced manufacturing of power electronics, solid-state lighting and sensors.

  7. Low temperature experiments in radiation biophysics

    International Nuclear Information System (INIS)

    Moan, J.

    1977-01-01

    The reasons for performing experiments in radiation biophysics at low temperatures, whereby electron spectra may be studied, are explained. The phenomenon of phosphorescence spectra observed in frozen aqueous solutions of tryptophan and adenosine is also described. Free radicals play an important part in biological radiation effects and may be studied by ESR spectroscopy. An ESR spectrum of T 1 bacteriophages irradiated dry at 130K is illustrated and discussed. Hydrogen atoms, which give lines on the spectrum, are believed to be those radiation products causing most biological damage in a dry system. Low temperature experiments are of great help in explaining the significance of direct and indirect effects. This is illustrated for the case of trypsin. (JIW)

  8. Dehydration of hydrated low-temperature tar

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, T

    1949-01-01

    Yoshida examined the mechanism of the dehydration of hydrated low-temperature tar with a microscope. The tar containing free carbon and coal dust is so stable that the removal of the above substances and water by a physical method is very difficult. Addition of light oil produced by fractionation of low-temperature tar facilitates the operations. Yoshida tried using the separate acid, neutral, and basic components of the light oil; the acid oil proved to be most effective. For many reasons it is convenient to use light oil as it is. In this method the quantity of light oil required is 2 to 3 times that of tar. But in supplementing the centrifugal method, the quantity of light oil needed might be only half the amount of tar.

  9. Manufacturing Demonstration Facility: Low Temperature Materials Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Graham, David E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Moon, Ji-Won [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Armstrong, Beth L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Datskos, Panos G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Duty, Chad E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gresback, Ryan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ivanov, Ilia N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jacobs, Christopher B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jellison, Gerald Earle [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jang, Gyoung Gug [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Joshi, Pooran C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jung, Hyunsung [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Meyer, III, Harry M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Phelps, Tommy [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-06-30

    The Manufacturing Demonstration Facility (MDF) low temperature materials synthesis project was established to demonstrate a scalable and sustainable process to produce nanoparticles (NPs) for advanced manufacturing. Previous methods to chemically synthesize NPs typically required expensive, high-purity inorganic chemical reagents, organic solvents and high temperatures. These processes were typically applied at small laboratory scales at yields sufficient for NP characterization, but insufficient to support roll-to-roll processing efforts or device fabrication. The new NanoFermentation processes described here operated at a low temperature (~60 C) in low-cost, aqueous media using bacteria that produce extracellular NPs with controlled size and elemental stoichiometry. Up-scaling activities successfully demonstrated high NP yields and quality in a 900-L pilot-scale reactor, establishing this NanoFermentation process as a competitive biomanufacturing strategy to produce NPs for advanced manufacturing of power electronics, solid-state lighting and sensors.

  10. Behaviour of polar crystals at low temperatures

    International Nuclear Information System (INIS)

    Drozhdin, S.N.; Novik, V.K.; Gavrilova, N.D.; Koptsik, V.A.; Popova, T.V.

    1975-01-01

    Temperature dependencies of pyrocoefficient for a wide class of various pyroactive crystals in the temperature range from 4,2 to 300 deg K were investigated. The problems to be solved were: to confirm a conclusion on the pyrocoefficient γsup(sigma) tending to zero at T → 0; to compare experimental data with conclusions of existing theories; to reveal specific features in the behaviour of both linear pyroelectrics and segnetoelectrics at low temperatures. The behaviour of the total pyrocoefficient for all crystals obeys the regularity γsup(sigma) → 0 at T → O. In the range of low temperatures the pyrocoefficient varies by the power law: γsup(sigma) approximately Tsup(α). For the majority of crystals studied α is close to 3. CdS, BeO, ZiNbO 3 and other crystals were studied

  11. Low-temperature conductivity of gadolinium sulfides

    Energy Technology Data Exchange (ETDEWEB)

    Mustafaeva, S. N., E-mail: solmust@gmail.com [Azerbaijan National Academy of Sciences, Institute of Physics (Azerbaijan); Asadov, S. M., E-mail: mirasadov@gmail.com [Azerbaijan National Academy of Sciences, Institute of Catalysis and Inorganic Chemistry (Azerbaijan)

    2016-09-15

    In samples of GdS{sub x} (x = 1.475–2) of various compositions, the conductivity temperature dependences are investigated for the case of direct current in the low-temperature region (4.2–225 K). The presence of the activation and activationless hopping mechanisms of charge transport over the band gap of the samples of GdS{sub x} phases is established. The parameters of localized states in GdS{sub x} are determined.

  12. Crystal growth from low-temperature solutions

    International Nuclear Information System (INIS)

    Sangwal, K.

    1994-01-01

    The state of the art in crystal growth from solutions at low-temperatures has been done. The thermodynamic and kinetic parameters have been discussed in respect to different systems. The methods of crystal growth from water and organic solutions and different variants of their technical realizations have been reviewed. Also the growth by chemical reactions and gel growth have been described. The large number of examples have been shown. 21 refs, 30 figs, 3 tabs

  13. Minimizing material damage using low temperature irradiation

    Science.gov (United States)

    Craven, E.; Hasanain, F.; Winters, M.

    2012-08-01

    Scientific advancements in healthcare driven both by technological breakthroughs and an aging and increasingly obese population have lead to a changing medical device market. Complex products and devices are being developed to meet the demands of leading edge medical procedures. Specialized materials in these medical devices, including pharmaceuticals and biologics as well as exotic polymers present a challenge for radiation sterilization as many of these components cannot withstand conventional irradiation methods. The irradiation of materials at dry ice temperatures has emerged as a technique that can be used to decrease the radiation sensitivity of materials. The purpose of this study is to examine the effect of low temperature irradiation on a variety of polymer materials, and over a range of temperatures from 0 °C down to -80 °C. The effectiveness of microbial kill is also investigated under each of these conditions. The results of the study show that the effect of low temperature irradiation is material dependent and can alter the balance between crosslinking and chain scission of the polymer. Low temperatures also increase the dose required to achieve an equivalent microbiological kill, therefore dose setting exercises must be performed under the environmental conditions of use.

  14. Computational Chemistry of Cyclopentane Low Temperature Oxidation

    KAUST Repository

    El Rachidi, Mariam

    2015-03-30

    Cycloalkanes are significant constituents of conventional fossil fuels, but little is known concerning their combustion chemistry and kinetics, particularly at low temperatures. This study investigates the pressure dependent kinetics of several reactions occurring during low-temperature cyclopentane combustion using theoretical chemical kinetics. The reaction pathways of the cyclopentyl + O2 adduct is traced to alkylhydroperoxide, cyclic ether, β-scission and HO2 elimination products. The calculations are carried out at the UCCSD(T)-F12b/cc-pVTZ-F12//M06-2X/6-311++G(d,p) level of theory. The barrierless entrance channel is treated using variable-reaction-coordinate transition state theory (VRC-TST) at the CASPT2(7e,6o) level of theory, including basis set, geometry relaxation and ZPE corrections. 1-D time-dependent multiwell master equation analysis is used to determine pressure-and temperature-dependent rate parameters of all investigated reactions. Tunneling corrections are included using Eckart barriers. Comparison with cyclohexane is used to elucidate the effect of ring size on the low temperature reactivity of naphthenes. The rate coefficients reported herein are suitable for use in cyclopentane and methylcyclopentane combustion models, even below ~900 K, where ignition is particularly sensitive to these pressure-dependent values.

  15. Neutron moderation at very low temperatures (1691)

    International Nuclear Information System (INIS)

    Lacaze, A.

    1961-04-01

    Starting from Harwell experiment carried out inside a low-power reactor, we intended to maintain a liquid hydrogen cell in a channel of the EL3 reactor (at Saclay) whose thermal neutrons flux is 10 14 neutrons/cm 2 /s. We tried to work out a device giving off an important beam of cold neutrons and able to operate in a way as automatic as possible during many consecutive day without a stop. Several circuits have already been achieved at very low temperatures but they brought out volumes and fluxes much lower than those we used this time. The difficulties we have met in carrying out such a device arose on the one hand from the very high energy release to which any kind of experiment is inevitably submitted when placed near the core of the reactor, on the other, hand from the very little room which is available in experimental channels of reactors. In such condition, it is necessary to use a moderator as effective as possible. This study is divided into three parts ; in the first part, we try to determine: a) conditions in which moderation takes place, hence the volume of the cell; b) materials likely to be used at low temperature and in pile; c) cooling system; hence we had to study fluid flow conditions at very low temperatures in very long ducts. The second part is devoted to the description of the device. The third part ventilates the results we have obtained. (author) [fr

  16. Low temperature surface chemistry and nanostructures

    Science.gov (United States)

    Sergeev, G. B.; Shabatina, T. I.

    2002-03-01

    The new scientific field of low temperature surface chemistry, which combines the low temperature chemistry (cryochemistry) and surface chemistry approaches, is reviewed in this paper. One of the most exciting achievements in this field of science is the development of methods to create highly ordered hybrid nanosized structures on different organic and inorganic surfaces and to encapsulate nanosized metal particles in organic and polymer matrices. We consider physical and chemical behaviour for the systems obtained by co-condensation of the components vapours on the surfaces cooled down to 4-10 and 70-100 K. In particular the size effect of both types, the number of atoms in the reactive species structure and the thickness of growing co-condensate film, on the chemical activity of the system is analysed in detail. The effect of the internal mechanical stresses on the growing interfacial co-condensate film formation and on the generation of fast (explosive) spontaneous reactions at low temperatures is discussed. The examples of unusual chemical interactions of metal atoms, clusters and nanosized particles, obtained in co-condensate films on the cooled surfaces under different conditions, are presented. The examples of highly ordered surface and volume hybrid nanostructures formation are analysed.

  17. Effect of heat treatment and hot isostatic pressing on the microstructure and mechanical properties of Inconel 625 alloy processed by laser powder bed fusion

    Energy Technology Data Exchange (ETDEWEB)

    Kreitcberg, Alena, E-mail: alena.kreitcberg.1@ens.etsmtl.ca [École de technologie supérieure, 110 Notre-Dame Street West, Montreal, Quebec H3C 1K3 Canada (Canada); Brailovski, Vladimir, E-mail: vladimir.brailovski@etsmtl.ca [École de technologie supérieure, 110 Notre-Dame Street West, Montreal, Quebec H3C 1K3 Canada (Canada); Turenne, Sylvain, E-mail: sylvain.turenne@polymtl.ca [École Polytechnique de Montréal, 2900 boul. Édouard-Montpetit, Montreal, Quebec H3T 1J4 Canada (Canada)

    2017-03-24

    The effect of different heat treatments and hot isostatic pressing on the microstructure and mechanical properties of laser powder bed fusion IN625 alloy was studied. The heat treatments were: stress relief annealing, recrystallization annealing and low-temperature solution treatment. The resulting microstructure and crystallographic textures were studied using optical and scanning electron microscopy. The mechanical properties of the as-built and post-treated IN625 alloy were obtained after tensile testing at room temperature and at 760 °C (1400 °F), and compared to those of an annealed wrought alloy of the same composition.

  18. 49 CFR 179.100-10 - Postweld heat treatment.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Postweld heat treatment. 179.100-10 Section 179...-10 Postweld heat treatment. (a) After welding is complete, steel tanks and all attachments welded... treatment is prohibited. (c) Tank and welded attachments, fabricated from ASTM A 240/A 240M (IBR, see § 171...

  19. Sucrose Phosphate Synthase and Sucrose Accumulation at Low Temperature 1

    Science.gov (United States)

    Guy, Charles L.; Huber, Joan L. A.; Huber, Steven C.

    1992-01-01

    The influence of growth temperature on the free sugar and sucrose phosphate synthase content and activity of spinach (Spinacia oleracea) leaf tissue was studied. When plants were grown at 25°C for 3 weeks and then transferred to a constant 5°C, sucrose, glucose, and fructose accumulated to high levels during a 14-d period. Predawn sugar levels increased from 14- to 20-fold over the levels present at the outset of the low-temperature treatment. Sucrose was the most abundant free sugar before, during, and after exposure to 5°C. Leaf sucrose phosphate synthase activity was significantly increased by the low-temperature treatment, whereas sucrose synthase and invertases were not. Synthesis of the sucrose phosphate synthase subunit was increased during and after low-temperature exposure and paralleled an increase in the steady-state level of the subunit. The increases in sucrose and its primary biosynthetic enzyme, sucrose phosphate synthase, are discussed in relation to adjustment of metabolism to low nonfreezing temperature and freezing stress tolerance. Images Figure 1 Figure 2 Figure 3 PMID:16652990

  20. Low-temperature tar and oil: properties and applications

    Energy Technology Data Exchange (ETDEWEB)

    Heinze, R

    1942-01-01

    In Germany the value of low-temperature tar is largely dependent on its fuel fractions; these vary with the coal and the method of carbonization (external heating or recirculated gases). Brown-coal tars can be processed by distillation, cracking under pressure, hydrogenation under pressure (largest volume of tar is processed by this method) and by solvent extraction, with EtOH, SO/sub 2/, or phenol. Each of these processes is discussed in detail. In the pressure-hydrogenation process, 1.25 kilogram of brown-coal tar yields approximately 1 kilogram of gasoline with an octane number of 60 to 70. Low-temperature tars from bituminous coals can be hydrogenated readily but are not well adapted to solvent extraction. Attempts should be made to produce tar approximating the desired characteristics for fuel directly from the carbonizing apparatus. For laboratory carbonization tests, an approximation to results secured by externally heated retorts is secured by using an insert consisting of a series of perforated trays in the 200-gram Fischer aluminum retort; this reduces the capacity to 100 gram. Fractional condensation is used to separate heavy oil, middle oil, and liquor; low-boiling products are condensed at -20/sup 0/ by solid CO/sub 2/.