High temperature heat exchange: nuclear process heat applications

International Nuclear Information System (INIS)

Vrable, D.L.

1980-09-01

The unique element of the HTGR system is the high-temperature operation and the need for heat exchanger equipment to transfer nuclear heat from the reactor to the process application. This paper discusses the potential applications of the HTGR in both synthetic fuel production and nuclear steel making and presents the design considerations for the high-temperature heat exchanger equipment

Dense high-temperature plasma transport processes

International Nuclear Information System (INIS)

Giniyatova, Sh.G.

2002-01-01

In this work the transport processes in dense high-temperature semiclassical plasma are studied on the base of the kinetic equation, where the semiclassical potential was used, in its collision integral. The coefficient of plasma electrical conductivity, viscosity and thermal conductivity were received. There were compared with the other authors' results. The Grad's method was used obtaining of viscosity and thermal coefficients. (author)

Understanding Fundamental Material Degradation Processes in High Temperature Aggressive Chemomechanical Environments

International Nuclear Information System (INIS)

2014-01-01

The objective of this project is to develop a fundamental understanding of the mechanisms that limit materials durability for very high-temperature applications. Current design limitations are based on material strength and corrosion resistance. This project will characterize the interactions of high-temperature creep, fatigue, and environmental attack in structural metallic alloys of interest for the very high-temperature gas-cooled reactor (VHTR) or Next Generation Nuclear Plant (NGNP) and for the associated thermo-chemical processing systems for hydrogen generation. Each of these degradation processes presents a major materials design challenge on its own, but in combination, they can act synergistically to rapidly degrade materials and limit component lives. This research and development effort will provide experimental results to characterize creep-fatigue-environment interactions and develop predictive models to define operation limits for high-temperature structural material applications. Researchers will study individually and in combination creep-fatigue-environmental attack processes in Alloys 617, 230, and 800H, as well as in an advanced Ni-Cr oxide dispersion strengthened steel (ODS) system. For comparison, the study will also examine basic degradation processes in nichrome (Ni-20Cr), which is a basis for most high-temperature structural materials, as well as many of the superalloys. These materials are selected to represent primary candidate alloys, one advanced developmental alloy that may have superior high-temperature durability, and one model system on which basic performance and modeling efforts can be based. The research program is presented in four parts, which all complement each other. The first three are primarily experimental in nature, and the last will tie the work together in a coordinated modeling effort. The sections are (1) dynamic creep-fatigue-environment process, (2) subcritical crack processes, (3) dynamic corrosion crack

Understanding Fundamental Material Degradation Processes in High Temperature Aggressive Chemomechanical Environments

Energy Technology Data Exchange (ETDEWEB)

Stubbins, James; Gewirth, Andrew; Sehitoglu, Huseyin; Sofronis, Petros; Robertson, Ian

2014-01-16

The objective of this project is to develop a fundamental understanding of the mechanisms that limit materials durability for very high-temperature applications. Current design limitations are based on material strength and corrosion resistance. This project will characterize the interactions of high-temperature creep, fatigue, and environmental attack in structural metallic alloys of interest for the very high-temperature gas-cooled reactor (VHTR) or Next–Generation Nuclear Plant (NGNP) and for the associated thermo-chemical processing systems for hydrogen generation. Each of these degradation processes presents a major materials design challenge on its own, but in combination, they can act synergistically to rapidly degrade materials and limit component lives. This research and development effort will provide experimental results to characterize creep-fatigue-environment interactions and develop predictive models to define operation limits for high-temperature structural material applications. Researchers will study individually and in combination creep-fatigue-environmental attack processes in Alloys 617, 230, and 800H, as well as in an advanced Ni-Cr oxide dispersion strengthened steel (ODS) system. For comparison, the study will also examine basic degradation processes in nichrome (Ni-20Cr), which is a basis for most high-temperature structural materials, as well as many of the superalloys. These materials are selected to represent primary candidate alloys, one advanced developmental alloy that may have superior high-temperature durability, and one model system on which basic performance and modeling efforts can be based. The research program is presented in four parts, which all complement each other. The first three are primarily experimental in nature, and the last will tie the work together in a coordinated modeling effort. The sections are (1) dynamic creep-fatigue-environment process, (2) subcritical crack processes, (3) dynamic corrosion – crack

Processing of high-temperature simulated waste glass in a continuous ceramic melter

International Nuclear Information System (INIS)

Barnes, S.M.; Brouns, R.A.; Hanson, M.S.

1980-01-01

Recent operations have demonstrated that high-melting-point glasses and glass-ceramics can be successfully processed in joule-heated, ceramic-lined melters with minor modifications to the existing technology. Over 500 kg of simulated waste glasses have been processed at temperatures up to 1410 0 C. The processability of the two high-temperature waste forms tested is similar to existing borosilicate waste glasses. High-temperature waste glass formulations produced in the bench-scale melter exhibit quality comparing favorably to standard waste glass formulations

Low temperature stabilization process for production of carbon fiber having structural order

Science.gov (United States)

Rios, Orlando; McGuire, Michael Alan; More, Karren Leslie; Tenhaeff, Wyatt Evan; Menchhofer, Paul A.; Paulauskas, Felix Leonard

2017-08-15

A method for producing a carbon fiber, the method comprising: (i) subjecting a continuous carbon fiber precursor having a polymeric matrix in which strength-enhancing particles are incorporated to a stabilization process during which the carbon fiber precursor is heated to within a temperature range ranging from the glass transition temperature to no less than 20.degree. C. below the glass transition temperature of the polymeric matrix, wherein the maximum temperature employed in the stabilization process is below 400.degree. C., for a processing time within said temperature range of at least 1 hour in the presence of oxygen and in the presence of a magnetic field of at least 1 Tesla, while said carbon fiber precursor is held under an applied axial tension; and (ii) subjecting the stabilized carbon fiber precursor, following step (i), to a carbonization process. The stabilized carbon fiber precursor, resulting carbon fiber, and articles made thereof are also described.

Safety Philosophy in Process Heat Plants Coupled to High Temperature Reactors

International Nuclear Information System (INIS)

Brown, Nicholas R.; Revankar, Shripad T.

2011-01-01

With the future availability of fossil fuel resources in doubt, high temperature nuclear reactors have the potential to be an important technology in the near term. Due to a high coolant outlet temperature, high temperature reactors (HTR) can be used to drive chemical plants that directly utilize process heat. Additionally, the high temperature improves the thermodynamic efficiency of the energy utilization. Many applications of high temperature reactors exist as a thermal driving vector for endothermic chemical process plants. Hydrogen generation using the General Atomics (GA) sulfur iodine (SI) cycle is one promising application of high temperature nuclear heat. The main chemical reactions in the SI cycle are: 1. I 2 +SO 2 + 2H 2 O → 2HI + H 2 SO 4 (Bunsen reaction) 2. H 2 SO 4 → H 2 O + SO 2 + 1/2O 2 (Sulfuric acid decomposition) 3. 2HI → H 2 + I 2 (Hydrogen Iodide decomposition). With the exception of hydrogen and oxygen, all relevant reactants are recycled within the process. However, there are many unresolved safety and operational issues related to implementation of such a coupled plant

Computational study of a high-temperature thermal nanoimprint lithographic (TNIL) process

Science.gov (United States)

Cleveland, Nicolas Joseph

As an emerging manufacturing technique, nanoimprint lithography (NIL) can fabricate micro and nanoscale features of microfluidic devices at very high accuracy and reliability. The process parameters such as pressure, temperature, and material properties play critical roles in the NIL process. In this work, the process of thermal nanoimprint lithography (TNIL) is studied computationally and the developed model can accurately predict the nano and micro-pattern geometry and quality from TNIL processes based on complex mold-resist interaction. Applications of this modeling technique range from micro- and nano-patterns used in micro-channels for biomedical devices to other applications such as biological/particle sensors or superhydrophobic surfaces. In high-temperature TNIL process, a polymer melt such as polymethyl-methacrylate (PMMA) is heated beyond the melting temperature so that it behaves predominantly as a fluid during the imprint process. The effects of surface tension and shear thinning become significant at or above the melting point, whereas the polymer melt can be modeled as a viscoelastic solid, solved with finite element analysis, when process temperature remains between the glass transition and melting temperatures. Additionally, the mold used in TNIL can deform since it is made of soft-rubbery elastomer such as polydimethylsiloxane (PDMS), and it is of interest to include the effect of subsequent mold deformation. Leakage between channels or significant variation in channel width can occur in micro-fluidic devices if mold deformation exceeds design tolerances. In the current work, fluid-structure interaction (FSI) technology is leveraged to solve for significant mold deformation and its effect on the polymer melt flow field during TNIL process. The simulation result is compared to experimental results. The FSI simulation result is also compared to the equivalent case with a rigid mold in place of flexible material, which shows results of differing mold

Processing methods for temperature-dependent MCNP libraries

International Nuclear Information System (INIS)

Li Songyang; Wang Kan; Yu Ganglin

2008-01-01

In this paper,the processing method of NJOY which transfers ENDF files to ACE (A Compact ENDF) files (point-wise cross-Section file used for MCNP program) is discussed. Temperatures that cover the range for reactor design and operation are considered. Three benchmarks are used for testing the method: Jezebel Benchmark, 28 cm-thick Slab Core Benchmark and LWR Benchmark with Burnable Absorbers. The calculation results showed the precision of the neutron cross-section library and verified the correct processing methods in usage of NJOY. (authors)

EFFECT OF TEMPERATURE ON THE PROCESS OF BEER PRIMARY FERMENTATION

OpenAIRE

Miriam Solgajová; Helena Frančáková; Štefan Dráb; Žigmund Tóth

2013-01-01

Beer is a very popular and widespread drink worldwide. Beer may be defined as a foamy alcoholic drink aerated by carbon dioxide that is formed during fermentation. Sensorial and analytical character of beer is mainly formed during process of primary fermentation. Our work has monitored the influence of temperature of fermentation substrate on the process of primary fermentation during beer production. Obtained values of temperature and apparent extract out of four brews of 10% light hopped wo...

EMPRESS: A European Project to Enhance Process Control Through Improved Temperature Measurement

Science.gov (United States)

Pearce, J. V.; Edler, F.; Elliott, C. J.; Rosso, L.; Sutton, G.; Andreu, A.; Machin, G.

2017-08-01

A new European project called EMPRESS, funded by the EURAMET program `European Metrology Program for Innovation and Research,' is described. The 3 year project, which started in the summer of 2015, is intended to substantially augment the efficiency of high-value manufacturing processes by improving temperature measurement techniques at the point of use. The project consortium has 18 partners and 5 external collaborators, from the metrology sector, high-value manufacturing, sensor manufacturing, and academia. Accurate control of temperature is key to ensuring process efficiency and product consistency and is often not achieved to the level required for modern processes. Enhanced efficiency of processes may take several forms including reduced product rejection/waste; improved energy efficiency; increased intervals between sensor recalibration/maintenance; and increased sensor reliability, i.e., reduced amount of operator intervention. Traceability of temperature measurements to the International Temperature Scale of 1990 (ITS-90) is a critical factor in establishing low measurement uncertainty and reproducible, consistent process control. Introducing such traceability in situ (i.e., within the industrial process) is a theme running through this project.

High Temperature Epoxy Foam: Optimization of Process Parameters

Directory of Open Access Journals (Sweden)

Samira El Gazzani

2016-06-01

Full Text Available For many years, reduction of fuel consumption has been a major aim in terms of both costs and environmental concerns. One option is to reduce the weight of fuel consumers. For this purpose, the use of a lightweight material based on rigid foams is a relevant choice. This paper deals with a new high temperature epoxy expanded material as substitution of phenolic resin, classified as potentially mutagenic by European directive Reach. The optimization of thermoset foam depends on two major parameters, the reticulation process and the expansion of the foaming agent. Controlling these two phenomena can lead to a fully expanded and cured material. The rheological behavior of epoxy resin is studied and gel time is determined at various temperatures. The expansion of foaming agent is investigated by thermomechanical analysis. Results are correlated and compared with samples foamed in the same temperature conditions. The ideal foaming/gelation temperature is then determined. The second part of this research concerns the optimization of curing cycle of a high temperature trifunctional epoxy resin. A two-step curing cycle was defined by considering the influence of different curing schedules on the glass transition temperature of the material. The final foamed material has a glass transition temperature of 270 °C.

Influence of processing temperature on the rheological behavior of PCL/MMT nanocomposites

International Nuclear Information System (INIS)

Marini, Juliano; Beatrice, Cesar A.G.; Favaro, Marcia M.; Bretas, Rosario E.S.; Branciforti, Marcia C.

2009-01-01

Polycaprolactone (PCL) is a biodegradable polymer; however, this polymer had low mechanical strength, limiting its applications. The addition of a lamellar silicate (MMT) can alter this behavior, especially when the filler is well dispersed and distributed thru the polymeric matrix. In this work the influence of the processing temperature in the structure of PCL/MMT nanocomposites was studied. The nanocomposites were obtained by melt intercalation in a Haake rheometer at two temperatures: 80 and 120 deg C. Wide angle X-ray analysis showed that the intercalation of the polymer chains into the clay's galleries was not influenced by the processing temperature. However, the steady state and dynamic rheological properties showed that the higher the processing temperature the better the dispersion and distribution of the clay thru the matrix, without having polymer degradation. (author)

Measuring gas temperature during spin-exchange optical pumping process

Science.gov (United States)

Normand, E.; Jiang, C. Y.; Brown, D. R.; Robertson, L.; Crow, L.; Tong, X.

2016-04-01

The gas temperature inside a Spin-Exchange Optical Pumping (SEOP) laser-pumping polarized 3He cell has long been a mystery. Different experimental methods were employed to measure this temperature but all were based on either modelling or indirect measurement. To date there has not been any direct experimental measurement of this quantity. Here we present the first direct measurement using neutron transmission to accurately determine the number density of 3He, the temperature is obtained using the ideal gas law. Our result showed a surprisingly high gas temperature of 380°C, compared to the 245°C of the 3He cell wall temperature and 178°C of the optical pumping oven temperature. This experiment result may be used to further investigate the unsolved puzzle of the "X-factor" in the SEOP process which places an upper bound to the 3He polarization that can be achieved. Additional spin relaxation mechanisms might exist due to the high gas temperature, which could explain the origin of the X-factor.

Control of surface temperature of an aluminum alloy billet by air flow during a heating process at elevated temperature

Energy Technology Data Exchange (ETDEWEB)

Choi, Young [KITECH, Cheonan (Korea, Republic of); Park, Joon Hong [Dong-A University, Busan (Korea, Republic of)

2016-06-15

The procedure of semi-solid forming is composed of heating a billet, forming, compression holding and ejecting step. There are several methods to heat a billet during semi-solid forming process such as electric heating and induction heating. Usually in semi-solid forming process, induction heating has been adopted to achieve more uniform temperature of semi-solid material. Although induction heating is better method than any others, however, there is still difference of temperature between internal part and surface part of semi-solid material. Worse yet, in case of high liquid fraction of semi-solid material, liquid of the billet will flow down though solid of the billet still remains, which is very difficult to handle. In the present study, induction heating of the billet during thixoforging process with forced surface cooling has been performed to obtain more uniform distribution of temperature, microstructure and shape of the billet. Distribution of temperature of the billets was measured and compared with that of conventional distribution of temperature. Microscopic and macroscopic aspects of the billets were discussed according to location of the measuring points. By this new induction heating method, not only temperature distributions over the whole billet become uniform, but also control of temperature distribution between inside and outside part of the billet is possible as user's experimental intentions,.

Modelling of peak temperature during friction stir processing of magnesium alloy AZ91

Science.gov (United States)

Vaira Vignesh, R.; Padmanaban, R.

2018-02-01

Friction stir processing (FSP) is a solid state processing technique with potential to modify the properties of the material through microstructural modification. The study of heat transfer in FSP aids in the identification of defects like flash, inadequate heat input, poor material flow and mixing etc. In this paper, transient temperature distribution during FSP of magnesium alloy AZ91 was simulated using finite element modelling. The numerical model results were validated using the experimental results from the published literature. The model was used to predict the peak temperature obtained during FSP for various process parameter combinations. The simulated peak temperature results were used to develop a statistical model. The effect of process parameters namely tool rotation speed, tool traverse speed and shoulder diameter of the tool on the peak temperature was investigated using the developed statistical model. It was found that peak temperature was directly proportional to tool rotation speed and shoulder diameter and inversely proportional to tool traverse speed.

Processing of bulk Bi-2223 high-temperature superconductor

Directory of Open Access Journals (Sweden)

Alexander Polasek

2005-12-01

Full Text Available The Bi2Sr2Ca2Cu3 O10+x (Bi-2223 is one of the main high temperature superconductors for applications. One of these applications is the Superconductor Fault Current Limiter (SCFCL, which is a very promising high temperature superconducting device. SCFCL's can be improved by using bulk superconductors with high critical currents, which requires a sufficiently dense and textured material. In the present work, a process for improving the microstructure of Bi-2223 bulk samples is investigated. Pressed precursor blocks are processed by sintering with a further partial melting step, in order to enhance the Bi-2223 grain texture and to healing cracks induced by pressing. In order to improve the microstructure, the precursor is mixed with silver powder before pressing. Samples with and without silver powder have been studied, with the aim of investigating the influence of silver on the microstructure evolution. The phase contents and the microstructure obtained have been analyzed through XRD and SEM/EDS. The electromagnetic characterization has been performed by Magnetic Susceptibility Analysis. We present and discuss the process and the properties of the superconducting blocks. High fractions of textured Bi-2223 grains have been obtained.

Modelling the behaviour of 210Po in high temperature processes

International Nuclear Information System (INIS)

Mora, J.C.; Robles, B.; Corbacho, J.A.; Gasco, Catalina; Gazquez, M.J.

2011-01-01

In several Naturally Occurring Radioactive Material (NORM) industries, relatively high temperatures are used as part of their industrial processes. In coal combustion, as occur in other high temperature processes, an increase of the activity concentration of every natural radioisotope is produced both, in residues and by-products. An additional increase can be observed in the activity concentration of radionuclides of elements with low boiling point. This work is centred in the increase of polonium, more precisely in its radioisotope Po-210, present in the natural chains, and with a half-life long enough to be considered for radiation protection purposes. This additional increase appears mainly in the residual particles that are suspended in the flue gases: the fly-ashes. Besides, scales, with a high concentration of this radioisotope, were observed. These scales are produced on surfaces with a temperature lower than the boiling point of the chemical element. Both, the accumulation in particles and the production of scales are attributed to condensation effects. When effective doses for the public and the workers are evaluated, taking into account these increases in activity concentrations, the use of theoretical models is necessary. In this work a theoretical description of those effects is presented. Moreover, a verification of the predictions of the model was performed by comparing them with measurements carried on in coal-fired power plants. The same description here presented is applicable in general to the behaviour of Po-210 in other NORM industries where high temperature processes involving raw materials are used, as can be ceramic, cement production, tiles production or steel processing.

Determination of temperature and pressure in the calcium reduction process

International Nuclear Information System (INIS)

Arceri, Mariana E.

1997-01-01

The calcium reduction process consists in the reduction of uranium tetrafluoride (UF 4 ) with calcium in a refractory material crucible, in order to obtain metallic uranium. The crucible is in turn contained in a steel reactor, heated by means of an induction coil to bring the reagents from the environmental temperature to the temperature necessary for the reaction starting. For the design of the reactor, mathematical expressions that allow to estimate the temperature and pressure of the system have been developed

Evaluation of extreme temperature events in northern Spain based on process control charts

Science.gov (United States)

Villeta, M.; Valencia, J. L.; Saá, A.; Tarquis, A. M.

2018-02-01

Extreme climate events have recently attracted the attention of a growing number of researchers because these events impose a large cost on agriculture and associated insurance planning. This study focuses on extreme temperature events and proposes a new method for their evaluation based on statistical process control tools, which are unusual in climate studies. A series of minimum and maximum daily temperatures for 12 geographical areas of a Spanish region between 1931 and 2009 were evaluated by applying statistical process control charts to statistically test whether evidence existed for an increase or a decrease of extreme temperature events. Specification limits were determined for each geographical area and used to define four types of extreme anomalies: lower and upper extremes for the minimum and maximum anomalies. A new binomial Markov extended process that considers the autocorrelation between extreme temperature events was generated for each geographical area and extreme anomaly type to establish the attribute control charts for the annual fraction of extreme days and to monitor the occurrence of annual extreme days. This method was used to assess the significance of changes and trends of extreme temperature events in the analysed region. The results demonstrate the effectiveness of an attribute control chart for evaluating extreme temperature events. For example, the evaluation of extreme maximum temperature events using the proposed statistical process control charts was consistent with the evidence of an increase in maximum temperatures during the last decades of the last century.

Short-term acclimation to warmer temperatures accelerates leaf carbon exchange processes across plant types.

Science.gov (United States)

Smith, Nicholas G; Dukes, Jeffrey S

2017-11-01

While temperature responses of photosynthesis and plant respiration are known to acclimate over time in many species, few studies have been designed to directly compare process-level differences in acclimation capacity among plant types. We assessed short-term (7 day) temperature acclimation of the maximum rate of Rubisco carboxylation (V cmax ), the maximum rate of electron transport (J max ), the maximum rate of phosphoenolpyruvate carboxylase carboxylation (V pmax ), and foliar dark respiration (R d ) in 22 plant species that varied in lifespan (annual and perennial), photosynthetic pathway (C 3 and C 4 ), and climate of origin (tropical and nontropical) grown under fertilized, well-watered conditions. In general, acclimation to warmer temperatures increased the rate of each process. The relative increase in different photosynthetic processes varied by plant type, with C 3 species tending to preferentially accelerate CO 2 -limited photosynthetic processes and respiration and C 4 species tending to preferentially accelerate light-limited photosynthetic processes under warmer conditions. R d acclimation to warmer temperatures caused a reduction in temperature sensitivity that resulted in slower rates at high leaf temperatures. R d acclimation was similar across plant types. These results suggest that temperature acclimation of the biochemical processes that underlie plant carbon exchange is common across different plant types, but that acclimation to warmer temperatures tends to have a relatively greater positive effect on the processes most limiting to carbon assimilation, which differ by plant type. The acclimation responses observed here suggest that warmer conditions should lead to increased rates of carbon assimilation when water and nutrients are not limiting. © 2017 John Wiley & Sons Ltd.

[Scientific connotation of processing Bombyx Batryticatus under high temperature].

Science.gov (United States)

Ma, Li; Wang, Xuan; Ma, Lin; Wang, Man-yuan; Qiu, Feng

2015-12-01

The aim of this study was to elucidate the scientific connotation of Bombyx Batryticatus processing with wheat bran under high temperature. The contents of soluble protein extracted from Bombyx Batryticatus and its processed products and the limited content of AFT in Bombyx Batryticatus and the processed one were compared. The concentration of protein was measured with the Bradford methods and the difference of protein between Bombyx Batryticatus and its processed products was compared by SDS-PAGE analysis. Aflatoxin B1, B2, G1, and G2 were determined by reversed-phase HPLC. The results showed that the soluble protein content of Bombyx Batryticatus and its processed products were (47.065 +/- 0.249), (29.756 +/- 1.961) mg x g(-1), correspondingly. Analysis of protein gel electrophoresis showed that there were no significant differences between the crude and processed one in protein varieties. 6 bands were detected: 31.90, 26.80, 18.71, 15.00, 10.18, 8.929 kDa. Below 10 kDa, the color of bands of the processed one was deeper than the crude one, which demonstrate that macromolecular protein was degradated into micromolecule. The content of AFG1, AFB1, AFG2, AFB2 were 0.382, 0.207, 0.223, 0.073 g x kg(-1), not exceeded 5 microg x kg(-1) while the processed one was not detected. Through processing with wheat bran under high temperature, the content of soluble protein in Bombyx Batryticatus decreased, the processing purpose for alleviating drug property was achieved. Meanwhile, the limited content of aflatoxins were reduced or cleared by processing procedure or absorbed by processing auxillary material, adding the safety of the traditional Chinese Medicine. In conclusion, as a traditional processing method, bran frying Bombyx Batryticatus was scientific and reasonable.

Acoustic levitation technique for containerless processing at high temperatures in space

Science.gov (United States)

Rey, Charles A.; Merkley, Dennis R.; Hammarlund, Gregory R.; Danley, Thomas J.

1988-01-01

High temperature processing of a small specimen without a container has been demonstrated in a set of experiments using an acoustic levitation furnace in the microgravity of space. This processing technique includes the positioning, heating, melting, cooling, and solidification of a material supported without physical contact with container or other surface. The specimen is supported in a potential energy well, created by an acoustic field, which is sufficiently strong to position the specimen in the microgravity environment of space. This containerless processing apparatus has been successfully tested on the Space Shuttle during the STS-61A mission. In that experiment, three samples wer successfully levitated and processed at temperatures from 600 to 1500 C. Experiment data and results are presented.

Temperature effect on protection diode for plasma-process induced charging damage

NARCIS (Netherlands)

Wang, Zhichun; Scarpa, A.; Smits, Sander M.; Kuper, F.G.; Salm, Cora

2002-01-01

In this paper, the leakage current of different drain-well diodes for plasma-charging protection has been simulated at high temperature. The simulation shows that the high ambient temperature, especially during plasma deposition process, enormously enhances the efficacy of the protection diodes in

Temperature dependent investigation on optically active process of higher-order bands in irradiated silicon

International Nuclear Information System (INIS)

Shi Yi; Nanjing Univ., JS; Wu Fengmei; Nanjing Univ., JS; Zheng Youdou; Nanjing Univ., JS; Suezawa, M.; Imai, M.; Sumino, K.

1996-01-01

Optically active processes of the higher-order bands (HOB) are investigated at different temperatures in fast neutron irradiated silicon using Fourier transform infrared absorption measurement. It is shown that the optically active process is nearly temperature independent below 80 K, the slow decay process remains up to a heating temperature of 180 K. The observations are analyzed in terms of the relaxation behavior of photoexcited carriers governed by fast neutron radiation induced defect clusters. (orig.)

Adaptive Process Controls and Ultrasonics for High Temperature PEM MEA Manufacture

Energy Technology Data Exchange (ETDEWEB)

Walczyk, Daniel F. [Rensselaer Polytechnic Inst., Troy, NY (United States)

2015-08-26

The purpose of this 5-year DOE-sponsored project was to address major process bottlenecks associated with fuel cell manufacturing. New technologies were developed to significantly reduce pressing cycle time for high temperature PEM membrane electrode assembly (MEA) through the use of novel, robust ultrasonic (U/S) bonding processes along with low temperature (<100°C) PEM MEAs. In addition, greater manufacturing uniformity and performance was achieved through (a) an investigation into the causes of excessive variation in ultrasonically and thermally bonded MEAs using more diagnostics applied during the entire fabrication and cell build process, and (b) development of rapid, yet simple quality control measurement techniques for use by industry.

A seeded ambient temperature ferrite process for treatment of AMD ...

African Journals Online (AJOL)

A seeded ambient temperature ferrite process for treatment of AMD waters: magnetite formation in the presence and absence of calcium ions under steady state operation. ... promising for AMD treatment. Keywords: Ferrite process, Magnetite seed, Calcium interference, Acid mine drainage (WaterSA: 2003 29(2): 117-124) ...

Students’ Conception on Heat and Temperature toward Science Process Skill

Science.gov (United States)

Ratnasari, D.; Sukarmin, S.; Suparmi, S.; Aminah, N. S.

2017-09-01

This research is aimed to analyze the effect of students’ conception toward science process skill. This is a descriptive research with subjects of the research were 10th-grade students in Surakarta from high, medium and low categorized school. The sample selection uses purposive sampling technique based on physics score in national examination four latest years. Data in this research collecting from essay test, two-tier multiple choice test, and interview. Two-tier multiple choice test consists of 30 question that contains an indicator of science process skill. Based on the result of the research and analysis, it shows that students’ conception of heat and temperature affect science process skill of students. The students’ conception that still contains the wrong concept can emerge misconception. For the future research, it is suggested to improve students’ conceptual understanding and students’ science process skill with appropriate learning method and assessment instrument because heat and temperature is one of physics material that closely related with students’ daily life.

Process Simulation of Aluminium Sheet Metal Deep Drawing at Elevated Temperatures

International Nuclear Information System (INIS)

Winklhofer, Johannes; Trattnig, Gernot; Lind, Christoph; Sommitsch, Christof; Feuerhuber, Hannes

2010-01-01

Lightweight design is essential for an economic and environmentally friendly vehicle. Aluminium sheet metal is well known for its ability to improve the strength to weight ratio of lightweight structures. One disadvantage of aluminium is that it is less formable than steel. Therefore complex part geometries can only be realized by expensive multi-step production processes. One method for overcoming this disadvantage is deep drawing at elevated temperatures. In this way the formability of aluminium sheet metal can be improved significantly, and the number of necessary production steps can thereby be reduced. This paper introduces deep drawing of aluminium sheet metal at elevated temperatures, a corresponding simulation method, a characteristic process and its optimization. The temperature and strain rate dependent material properties of a 5xxx series alloy and their modelling are discussed. A three dimensional thermomechanically coupled finite element deep drawing simulation model and its validation are presented. Based on the validated simulation model an optimised process strategy regarding formability, time and cost is introduced.

Estimation of weld nugget temperature by thermography method in resistance projection welding process

International Nuclear Information System (INIS)

Setty, D.S.; Rameswara Roa, A.; Hemantha Rao, G.V.S.; Jaya Raj, R.N.

2008-01-01

In the Pressurized Heavy Water Reactor (PHWR) fuel manufacturing, zirconium alloy appendages like spacer and bearing pads are welded to the thin wall zirconium alloy fuel tubes by using resistance projection welding process. Out of many joining processes available, resistance-welding process is reliable, environment friendly and best suitable for mass production applications. In the fuel assembly, spacer pads are used to get the required inter-element spacing and Bearing pads are used to get the required load-bearing surface for the fuel assembly. Performance of the fuel assembly in the reactor is greatly influenced by these weld joint's quality. Phase transformation from α to β phase is not acceptable while welding these tiny appendages. At present only destructive metallography test is available for this purpose. This can also be achieved by measuring weld nugget temperature where in the phase transformation temperature for zirconium alloy material is 853 o C. The temperature distribution during resistance welding of tiny parts cannot be measured by conventional methods due to very small space and short weld times involved in the process. Shear strength, dimensional accuracy and weld microstructures are some of the key parameters used to measure the quality of appendage weld joints. Weld parameters were optimized with the help of industrial experimentation methodology. Individual projection welding by split electrode concept, and during welding on empty tube firm support is achieved on inner side of the tube by using expandable pneumatic mandrel. In the present paper, an attempt was made to measure the weld nugget temperature by thermography technique and is correlated with standard microstructures of zirconium alloy material. The temperature profiles in the welding process are presented for different welding conditions. This technique has helped in measuring the weld nugget temperature more accurately. It was observed that in the present appendage welding

Analyzing the effect of tool edge radius on cutting temperature in micro-milling process

Science.gov (United States)

Liang, Y. C.; Yang, K.; Zheng, K. N.; Bai, Q. S.; Chen, W. Q.; Sun, G. Y.

2010-10-01

Cutting heat is one of the important physical subjects in the cutting process. Cutting heat together with cutting temperature produced by the cutting process will directly have effects on the tool wear and the life as well as on the workpiece processing precision and surface quality. The feature size of the workpiece is usually several microns. Thus, the tiny changes of cutting temperature will affect the workpiece on the surface quality and accuracy. Therefore, cutting heat and temperature generated in micro-milling will have significantly different effect than the one in the traditional tools cutting. In this paper, a two-dimensional coupled thermal-mechanical finite element model is adopted to determine thermal fields and cutting temperature during the Micro-milling process, by using software Deform-2D. The effect of tool edge radius on effective stress, effective strain, velocity field and cutting temperature distribution in micro-milling of aluminum alloy Al2024-T6 were investigated and analyzed. Also, the transient cutting temperature distribution was simulated dynamically. The simulation results show that the cutting temperature in Micro-milling is lower than those occurring in conventional milling processes due to the small loads and low cutting velocity. With increase of tool edge radius, the maximum temperature region gradually occurs on the contact region between finished surfaced and flank face of micro-cutter, instead of the rake face or the corner of micro-cutter. And this phenomenon shows an obvious size effect.

High temperature properties and processes in ceramics: thermomigration

International Nuclear Information System (INIS)

1978-01-01

The focus of this program is on the effects of large temperature gradients on the transport processes, the defect structure and resulting physical properties of ceramics. In particular, the transport of ions due to thermal gradients is one of the least understood phenomenon in materials science and is presumably based on fundamental understanding of thermodynamics, atomistic kinetic processes, and structure-property relationships. The purpose of this research is to systematically consider each of the elements of atomic transport due to driving forces other than composition gradients in a model ceramic system

High-temperature process heat applications with an HTGR

International Nuclear Information System (INIS)

Quade, R.N.; Vrable, D.L.

1980-04-01

An 842-MW(t) HTGR-process heat (HTGR-PH) design and several synfuels and energy transport processes to which it could be coupled are described. As in other HTGR designs, the HTGR-PH has its entire primary coolant system contained in a prestressed concrete reactor vessel (PCRV) which provides the necessary biological shielding and pressure containment. The high-temperature nuclear thermal energy is transported to the externally located process plant by a secondary helium transport loop. With a capability to produce hot helium in the secondary loop at 800 0 C (1472 0 F) with current designs and 900 0 C (1652 0 F) with advanced designs, a large number of process heat applications are potentially available. Studies have been performed for coal liquefaction and gasification using nuclear heat

An analysis of hot plate initial temperature effect on rectangular narrow gap quenching process

International Nuclear Information System (INIS)

M-Hadi Kusuma; Mulya Juarsa; Anhar Riza Antariksawan; Nandy Putra

2012-01-01

The understanding about thermal management in the event of a severe accident such as the melting nuclear reactor fuel and reactor core, became a priority to maintain the integrity of reactor pressure vessel. Thus the debris will not out from the reactor pressure vessel and resulting impact of more substantial to the environment. One way to maintain the integrity of the reactor pressure vessel was cooling of the excess heat generated due to the accident. To get understanding of this aspect, there search focused on the effect of the initial temperature of the hot plate in the rectangular narrow gap quenching process. The initial temperature effect on quenching process is related to cooling process (thermal management) when the occurrence of a nuclear accident due to loss of coolant accident or severe accident. In order to address the problem, it is crucial to conduct research to get a better understanding of thermal management regarding to nuclear cooling accident. The research focused on determining the rewetting temperature of hot plate cooling on 220°C, 400°C, and 600°C with 0.2 liters/sec cooling water flowrate. Experiments were carried out by injecting 85°C cooling water temperature into the narrow gap at flowrates of 0.2 liters/sec. Data of transient temperature measurements were recorded using a data acquisition system in order to know the rewetting temperature during the quenching process. This study aims to understand the effect of hot plate initial temperature on rewetting during rectangular narrow gap quenching process. The results obtained show that the rewetting point on cooling the hot plate 220°C, 400°C and 600°occurs at varying rewetting temperatures. At 220°C hot plate initial temperature, the rewetting temperature occurs on 220°C. At 400°C hot plate initial temperature, the rewetting temperature occurs on 379.51°C. At 600°C hot plate initial temperature, the rewetting temperature occurs on 426.63°C. Significant differences of hot plate

Processing Interband Cascade Laser for High Temperature CW Operation

National Research Council Canada - National Science Library

Tober, Richard

2004-01-01

A narrow ridge-waveguide mid-IR interband cascade laser based on Type-II InAs/GaInSh heterostructures processed with a thick gold heat spreading layer operated CW at temperatures ranging from 80 K to 214.4 K...

Temperature regulates deterministic processes and the succession of microbial interactions in anaerobic digestion process

Czech Academy of Sciences Publication Activity Database

Lin, Qiang; De Vrieze, J.; Li, Ch.; Li, J.; Li, J.; Yao, M.; Heděnec, Petr; Li, H.; Li, T.; Rui, J.; Frouz, Jan; Li, X.

2017-01-01

Roč. 123, October (2017), s. 134-143 ISSN 0043-1354 Institutional support: RVO:60077344 Keywords : anaerobic digestion * deterministic process * microbial interactions * modularity * temperature gradient Subject RIV: DJ - Water Pollution ; Quality OBOR OECD: Water resources Impact factor: 6.942, year: 2016

A reactor/receiver-concept for liquid-phase high-temperature processes

Energy Technology Data Exchange (ETDEWEB)

Schmidt-Traub, H.; Hahm, T. [Dortmund Univ. (Germany). Dept. of Chemical Engineering

1997-12-31

Besides the conversion of solar light to electricity solar energy can be used directly in photo- and thermochemistry. In the temperature range from 1000 to 2000 K there is a high demand for industrial process heat offering a variety of possibilities for solar thermal applications. Especially in the field of liquid-phase high-temperature processes there are hardly no solar thermal applications which exceed the stage of laboratory experiments. It was therefore the aim of two projects financed by the AG Solar of North Rhine-Westphalia, Germany, to develop concepts for commercial scale solar thermal plants and to judge them economically and ecologically. Some general problems have to be overcome to realize a commercial scale solar thermal plant for liquid-phase processes. The concept developed consists of a heliostat field, a tower reflector and an open receiver with a closed reaction chamber. The feasibility of a solar thermal plant for high-temperature liquid-phase processes has been shown in principle. The projected plant consists of a 4400 m{sup 2} heliostat field, a tower plus reflecting mirrors with a total area of 220 m{sup 2} and an open receiver with a closed annular reaction zone. For temperatures below 1700 K the overall efficiency is high enough to yield energetic amortization times of less than 1 year. For a further improvement and a verification of the calculation a closer look at the reactor/receiver and its heat transfer processes is necessary. This is done by using a mixed strategy of experiments and simulation. First experiments were carried out with a semitransparent salt and an opaque metal. The first stage of the experiments will end during the next weeks and their results have to be compared with the simulation. The simulation will then be extended to transparent melts. The second stage of the experiments which include the reaction chamber will start in 1997. An improvement of the reactor might be achieved using nonimaging concentrators to further

Acoustic levitation for high temperature containerless processing in space

Science.gov (United States)

Rey, C. A.; Sisler, R.; Merkley, D. R.; Danley, T. J.

1990-01-01

New facilities for high-temperature containerless processing in space are described, including the acoustic levitation furnace (ALF), the high-temperature acoustic levitator (HAL), and the high-pressure acoustic levitator (HPAL). In the current ALF development, the maximum temperature capabilities of the levitation furnaces are 1750 C, and in the HAL development with a cold wall furnace they will exceed 2000-2500 C. The HPAL demonstrated feasibility of precursor space flight experiments on the ground in a 1 g pressurized-gas environment. Testing of lower density materials up to 1300 C has also been accomplished. It is suggested that advances in acoustic levitation techniques will result in the production of new materials such as ceramics, alloys, and optical and electronic materials.

Atomic processes in high temperature plasmas

International Nuclear Information System (INIS)

Hahn, Y.

1991-07-01

This is the final report on the project Atomic Processes in High Temperature Plasmas', which has been completed in June 30, 1991. The original contract started in 1978. The dielectronic recombination (DR) rate coefficients were calculated for ions with the number of electrons N = 1, 2, 3, 4, 5, 10, 11, and 12. The result was then used to construct a new and improved rate formula. Other important resonant processes, which are closely related to DR, were also studied to interpret experiments and to test the DR theory. The plasma field and the density effects on the rate coefficients was found to be important, and a consistent correction procedure is being developed. The available data on the DR rates and their accuracy do not yet fully meet the requirement for plasma modeling; there are serious gaps in the available data, and the currently adopted theoretical procedure needs improvements. Critical assessment of the current status of the DR problem is presented, and possible future work needed is summarized

Nuclear process heat at high temperature: Application, realization and development programme

International Nuclear Information System (INIS)

Sammeck, K.H.; Fischer, R.

1976-01-01

Studies in the Federal Republic of Germany (FRG), the USA and the United Kingdom have shown that high-temperature helium energy from an HTR can advantageously be utilized for coal gasification and other fossil fuel conversion processes, and that a substantial demand for substitute natural gas (SNG) can be expected in the future. These results are based on plant design studies, economic assessments and basic development efforts in the field of coal gasification with nuclear heat, which in the FRG were carried out by Arbeitsgemeinschaft Nukleare Prozesswaerme (ANP)-members, HRB and KFA Juelich. Nuclear process plants are based on different gasification processes, resulting in different concepts of the nuclear heat system. In the case of hydro-gasification it is expected that steam reformers, arranged within the primary circuit of the reactor, will be heated directly by the primary helium. In the case of steam gasification, the high-temperature energy must be transferred to the gasification process via an intermediate circuit which is coupled to a gasifier outside the containment. In both cases the design of the nuclear reactor resembles an HTR for electricity generation. The main objectives of the development of nuclear process heat are to increase the helium outlet temperature of the reactor up to 950 0 C, to develop metallic alloys for high-temperature components such as heat exchangers, to design and construct a hot-gas duct, a steam reformer and a helium-helium heat exchanger and to develop the gasification processes. The nuclear safety regulations and the interface problems between the reactor, the process plant and the electricity generating plant have to be considered thoroughly. The Arbeitsgemeinschaft Nukleare Prozesswaerme and HRB started a development programme, in close collaboration with KFA Juelich, which will lead to the construction of a prototype plant for coal gasification with nuclear heat within 5 to 5 1/2 years. A survey of the main objectives

High-temperature Raman spectroscopy of solid oxide fuel cell materials and processes.

Science.gov (United States)

Pomfret, Michael B; Owrutsky, Jeffrey C; Walker, Robert A

2006-09-07

Chemical and material processes occurring in high temperature environments are difficult to quantify due to a lack of experimental methods that can probe directly the species present. In this letter, Raman spectroscopy is shown to be capable of identifying in-situ and noninvasively changes in material properties as well as the formation and disappearance of molecular species on surfaces at temperatures of 715 degrees C. The material, yttria-stabilized zirconia or YSZ, and the molecular species, Ni/NiO and nanocrystalline graphite, factor prominently in the chemistry of solid oxide fuel cells (SOFCs). Experiments demonstrate the ability of Raman spectroscopy to follow reversible oxidation/reduction kinetics of Ni/NiO as well as the rate of carbon disappearance when graphite, formed in-situ, is exposed to a weakly oxidizing atmosphere. In addition, the Raman active phonon mode of YSZ shows a temperature dependent shift that correlates closely with the expansion of the lattice parameter, thus providing a convenient internal diagnostic for identifying thermal gradients in high temperature systems. These findings provide direct insight into processes likely to occur in operational SOFCs and motivate the use of in-situ Raman spectroscopy to follow chemical processes in these high-temperature, electrochemically active environments.

Effect of processing temperature on the bitumen/MDI-PEG reactivity

Energy Technology Data Exchange (ETDEWEB)

Martin-Alfonso, M.J.; Partal, P.; Navarro, F.J.; Garcia-Morales, M. [Departamento de Ingenieria Quimica, Facultad de Ciencias Experimentales, Campus de ' El Carmen' , Universidad de Huelva, 21071, Huelva (Spain); Bordado, J.C.M. [Chemical and Biological Engineering Department, IBB, Instituto Superior Tecnico, Av. Rovisco Pais 1049-001 Lisbon (Portugal); Diogo, A.C. [Materials Engineering Department, Instituto Superior Tecnico, Av. Rovisco Pais 1049-001 Lisbon (Portugal)

2009-04-15

Reactive polymers are lately gaining acceptance to give added value to a residue of the crude oil refining process such as bitumen. The resulting material should display enhanced mechanical properties to be considered for advanced applications in construction. In the present paper, we report the effect of processing temperature on the reaction between bitumen compounds and an isocyanate-based reactive polymer, synthesized by reaction of polymeric MDI (4,4'-diphenylmethane diisocyanate) with a low molecular weight polyethylene-glycol (PEG). Rheokinetics experiments, viscosity measurements at 60 C, atomic force microscopy (AFM) characterization, thin layer chromatography (TLC-FID) analysis and thermogravimetric studies (TGA) were performed on the reactive polymer and on samples of MDI-PEG modified bitumen containing 2 wt.% of the polymer. Results showed the existence of an optimum processing temperature arisen as a consequence of opposite effects: microstructural availability for the formation of a polymer-bitumen network, reaction ability and polymer thermal degradation. Consequently, this study aims to serve as a guideline for the refining and asphalt industries facing the stage of selecting the optimum processing parameters. (author)

EFFECT OF TEMPERATURE ON THE PROCESS OF BEER PRIMARY FERMENTATION

Directory of Open Access Journals (Sweden)

Miriam Solgajová

2013-02-01

Full Text Available Beer is a very popular and widespread drink worldwide. Beer may be defined as a foamy alcoholic drink aerated by carbon dioxide that is formed during fermentation. Sensorial and analytical character of beer is mainly formed during process of primary fermentation. Our work has monitored the influence of temperature of fermentation substrate on the process of primary fermentation during beer production. Obtained values of temperature and apparent extract out of four brews of 10% light hopped wort has been recorded, during the process of primary fermentation carried out in mini brewery of SPU. We have compared our results with theoretical values of primary fermentation process commonly achieved in conditions of industrial breweries. It was found out that our results differ in some ways, moreover they exceed theoretically given values which was caused due to different construction of mini brewery fermentation tank in comparison with industrial brewery technologies. Beer produced in mini brewery of SPU showed in sensorial tests very good quality without any strange odour and any strange taste.

Biochar Preparation from Simulated Municipal Solid Waste Employing Low Temperature Carbonization Process

Science.gov (United States)

Areeprasert, C.; Leelachaikul, P.; Jangkobpattana, G.; Phumprasop, K.; Kiattiwat, T.

2018-02-01

This paper presents an investigation on carbonization process of simulated municipal solid waste (MSW). Simulated MSW consists of a representative of food residue (68%), plastic waste (20%), paper (8%), and textile (4%). Laboratory-scale carbonization was performed in this study using a vertical-type pyrolyzer varying carbonization temperature (300, 350, 400, and 450 °C) and heating rate (5, 10, 15, and 20 °C/min). Appearance of the biochar product was in black and the volume was significantly reduced. Low carbonization temperature (300 °C) might not completely decompose plastic materials in MSW. Results showed that the carbonization at the temperature of 400 °C with the heating rate of 5 °C/min was the optimal condition. The yield of biochar from the optimal process was 50.6% with the heating value of 26.85 MJ/kg. Energy input of the process was attributed to water evaporation and the decomposition of plastics and paper. Energy output of the process was highest at the optimal condition. Energy output and input ratio was around 1.3-1.7 showing the feasibility of the carbonization process in all heating rate condition.

Processes governing the temperature structure of the tropical tropopause layer (Invited)

Science.gov (United States)

Birner, T.

2013-12-01

The tropical tropopause layer (TTL) is among the most important but least understood regions of the global climate system. The TTL sets the boundary condition for atmospheric tracers entering the stratosphere. Specifically, TTL temperatures control stratospheric water vapor concentrations, which play a key role in the radiative budget of the entire stratosphere with implications for tropospheric and surface climate. The TTL shows a curious stratification structure: temperature continues to decrease beyond the level of main convective outflow (~200 hPa) up to the cold point tropopause (~100 hPa), but TTL lapse rates are smaller than in the upper troposphere. A cold point tropopause well separated from the level of main convective outflow requires TTL cooling which may be the result of: 1) the detailed radiative balance in the TTL, 2) large-scale upwelling (forced by extratropical or tropical waves), 3) the large-scale hydrostatic response aloft deep convective heating, 4) overshooting convection, 5) breaking gravity waves. All of these processes may act in isolation or combine to produce the observed TTL temperature structure. Here, a critical discussion of these processes / mechanisms and their role in lifting the cold point tropopause above the level of main convective outflow is presented. Results are based on idealized radiative-convective equilibrium model simulations, contrasting single-column with cloud-resolving simulations, as well on simulations with chemistry-climate models and reanalysis data. While all of the above processes are capable of producing a TTL-like region in isolation, their combination is found to produce important feedbacks. In particular, both water vapor and ozone are found to have strong radiative effects on TTL temperatures, highlighting important feedbacks between transport circulations setting temperatures and tracer structures and the resulting tracer structures in turn affecting temperatures.

Temperature measurement of RE123 bulk superconductors on magnetizing process

International Nuclear Information System (INIS)

Yokoyama, K.; Kaneyama, M.; Oka, T.; Fujishiro, H.; Noto, K.

2004-01-01

We study on the magnetization behavior of to magnetize RE123 bulk superconductors to apply it as strong magnets. Through magnetizing process, the temperature of bulk superconductors is raised by pinning loss caused by the magnetic fluxes motion (e.g. flux jump of flux flow), and the trapped field is decreased. This paper presents the measurement of temperature changes of Sm123 bulk superconductors during the exciting process by iteratively magnetizing pulsed-field operation with reducing amplitudes (IMRA) method. Five thermocouples are put on the surface of Sm123 bulk superconductor of 46 mm in diameter. The temperatures at the center, on the growth sector boundary (GSB) line and in the sector region surrounded by GSB's line (inter-GSB region) are monitored. The temperature at a cold stage is also measured. A Hall sensor is attached near the center thermocouple to measure the trapped field. After a bulk superconductor is cooled by the GM type refrigerator until 40 K, iterative pulsed-fields of 2.32-5.42 T are applied by a magnetizing coil. When high magnetic field of 5.42 T is applied, a temperature of bulk superconductor reaches to 72.4 K and the magnetic field distribution has C form with which a part of circle is dented, and then, a trapped field is 2.28 T. When a lower magnetic field of 4.64 T is applied, a maximum temperature is 68.3 K and a trapped field is raised to 2.70 T, and moreover, the distribution becomes round shape like field-cooling method (FC). We showed clearly that heat generation by pinning loss was related to the mechanism of magnetic field capture

Linear and nonlinear post-processing of numerically forecasted surface temperature

Directory of Open Access Journals (Sweden)

M. Casaioli

2003-01-01

Full Text Available In this paper we test different approaches to the statistical post-processing of gridded numerical surface air temperatures (provided by the European Centre for Medium-Range Weather Forecasts onto the temperature measured at surface weather stations located in the Italian region of Puglia. We consider simple post-processing techniques, like correction for altitude, linear regression from different input parameters and Kalman filtering, as well as a neural network training procedure, stabilised (i.e. driven into the absolute minimum of the error function over the learning set by means of a Simulated Annealing method. A comparative analysis of the results shows that the performance with neural networks is the best. It is encouraging for systematic use in meteorological forecast-analysis service operations.

Extreme temperature robust optical sensor designs and fault-tolerant signal processing

Science.gov (United States)

Riza, Nabeel Agha [Oviedo, FL; Perez, Frank [Tujunga, CA

2012-01-17

Silicon Carbide (SiC) probe designs for extreme temperature and pressure sensing uses a single crystal SiC optical chip encased in a sintered SiC material probe. The SiC chip may be protected for high temperature only use or exposed for both temperature and pressure sensing. Hybrid signal processing techniques allow fault-tolerant extreme temperature sensing. Wavelength peak-to-peak (or null-to-null) collective spectrum spread measurement to detect wavelength peak/null shift measurement forms a coarse-fine temperature measurement using broadband spectrum monitoring. The SiC probe frontend acts as a stable emissivity Black-body radiator and monitoring the shift in radiation spectrum enables a pyrometer. This application combines all-SiC pyrometry with thick SiC etalon laser interferometry within a free-spectral range to form a coarse-fine temperature measurement sensor. RF notch filtering techniques improve the sensitivity of the temperature measurement where fine spectral shift or spectrum measurements are needed to deduce temperature.

Exploring the limits: A low-pressure, low-temperature Haber-Bosch process

Science.gov (United States)

Vojvodic, Aleksandra; Medford, Andrew James; Studt, Felix; Abild-Pedersen, Frank; Khan, Tuhin Suvra; Bligaard, T.; Nørskov, J. K.

2014-04-01

The Haber-Bosch process for ammonia synthesis has been suggested to be the most important invention of the 20th century, and called the ‘Bellwether reaction in heterogeneous catalysis’. We examine the catalyst requirements for a new low-pressure, low-temperature synthesis process. We show that the absence of such a process for conventional transition metal catalysts can be understood as a consequence of a scaling relation between the activation energy for N2 dissociation and N adsorption energy found at the surface of these materials. A better catalyst cannot obey this scaling relation. We define the ideal scaling relation characterizing the most active catalyst possible, and show that it is theoretically possible to have a low pressure, low-temperature Haber-Bosch process. The challenge is to find new classes of catalyst materials with properties approaching the ideal, and we discuss the possibility that transition metal compounds have such properties.

Temperature Control of Heating Zone for Drying Process: Effect of Air Velocity Change

Directory of Open Access Journals (Sweden)

Wutthithanyawat Chananchai

2016-01-01

Full Text Available This paper proposes a temperature control technique to adjust air temperature in a heating zone for drying process. The controller design is achieved by using an internal model control (IMC approach. When the IMC controller parameters were designed by calculating from an actual process transfer function estimated through an open-loop step response with input step change from 50% to 60% at a reference condition at air velocity of 1.20 m/s, the performance of temperature controller was experimentally tested by varying an air velocity between 1.32 m/s and 1.57 m/s, respectively. The experimental results showed that IMC controller had a high competency for controlling the drying temperature.

Hydrogen production from biomass pyrolysis gas via high temperature steam reforming process

International Nuclear Information System (INIS)

Wongchang, Thawatchai; Patumsawad, Suthum

2010-01-01

Full text: The aim of this work has been undertaken as part of the design of continuous hydrogen production using the high temperature steam reforming process. The steady-state test condition was carried out using syngas from biomass pyrolysis, whilst operating at high temperatures between 600 and 1200 degree Celsius. The main reformer operating parameters (e.g. temperature, resident time and steam to biomass ratio (S/B)) have been examined in order to optimize the performance of the reformer. The operating temperature is a key factor in determining the extent to which hydrogen production is increased at higher temperatures (900 -1200 degree Celsius) whilst maintaining the same as resident time and S/B ratio. The effects of exhaust gas composition on heating value were also investigated. The steam reforming process produced methane (CH 4 ) and ethylene (C 2 H 4 ) between 600 to 800 degree Celsius and enhanced production ethane (C 2 H 6 ) at 700 degree Celsius. However carbon monoxide (CO) emission was slightly increased for higher temperatures all conditions. The results show that the use of biomass pyrolysis gas can produce higher hydrogen production from high temperature steam reforming. In addition the increasing reformer efficiency needs to be optimized for different operating conditions. (author)

Processing of high-temperature superconductors at high strain rates

International Nuclear Information System (INIS)

Mamalis, A.G.; Pantazsopoulos, G.; Manolakos, D.E.; Szalay, A.

2000-01-01

This new book provides, for the first time, a systematic, unified presentation of all steps in the processing of high-temperature superconductor materials, ranging from synthesis of various systems to fabrication and industrial applications. Also covered are characterization techniques and current directions in research and development. The authors are leading specialists who bring to this new book their many years of experience in research, education and industrial engineering work in superconductor materials. This book is primarily focused on the bulk-fabrication techniques of high-temperature ceramic superconducting components, especially on the combination of dynamic powder-consolidation and subsequent deformation processing. The properties of these ceramics, which are difficult-to-form materials by applying conventional techniques, are combined for the net-shape manufacturing of such components for the construction of HTS deviceshor e llipsis. However, very important topics such as superconducting structures, chemical synthesis, film fabrication and characterization techniques are also reviewedhor e llipsis to provide a complete, comprehensive view of superconductors engineering

Processed dairy beverages pH evaluation: consequences of temperature variation.

Science.gov (United States)

Ferreira, Fabiana Vargas; Pozzobon, Roselaine Terezinha

2009-01-01

This study assessed the pH from processed dairy beverages as well as eventual consequences deriving from different ingestion temperatures. 50 adults who accompanied children attended to at the Dentistry School were randomly selected and they answered a questionnaire on beverages. The beverages were divided into 4 groups: yogurt (GI) fermented milk (GII), chocolate-based products (GIII) and fermented dairy beverages (GIV). They were asked which type, flavor and temperature. The most popular beverages were selected, and these made up the sample. A pH meter Quimis 400A device was used to verify pH. The average pH from each beverage was calculated and submitted to statistical analysis (Variance and Tukey test with a 5% significance level). for groups I, II and III beverages, type x temperature interaction was significant, showing the pH averages were influenced by temperature variation. At iced temperatures, they presented lower pH values, which were considered statistically significant when compared to the values found for the same beverages at room temperature. All dairy beverages, with the exception of the chocolate-based type presented pH below critical level for enamel and present corrosive potential; as to ingestion temperature, iced temperature influenced pH reducing its values, in vitro.

Development of high temperature containerless processing equipment and the design and evaluation of associated systems required for microgravity materials processing and property measurements

Science.gov (United States)

Rey, Charles A.

1991-03-01

The development of high temperature containerless processing equipment and the design and evaluation of associated systems required for microgravity materials processing and property measurements are discussed. Efforts were directed towards the following task areas: design and development of a High Temperature Acoustic Levitator (HAL) for containerless processing and property measurements at high temperatures; testing of the HAL module to establish this technology for use as a positioning device for microgravity uses; construction and evaluation of a brassboard hot wall Acoustic Levitation Furnace; construction and evaluation of a noncontact temperature measurement (NCTM) system based on AGEMA thermal imaging camera; construction of a prototype Division of Amplitude Polarimetric Pyrometer for NCTM of levitated specimens; evaluation of and recommendations for techniques to control contamination in containerless materials processing chambers; and evaluation of techniques for heating specimens to high temperatures for containerless materials experimentation.

Development of high temperature containerless processing equipment and the design and evaluation of associated systems required for microgravity materials processing and property measurements

Science.gov (United States)

Rey, Charles A.

1991-01-01

The development of high temperature containerless processing equipment and the design and evaluation of associated systems required for microgravity materials processing and property measurements are discussed. Efforts were directed towards the following task areas: design and development of a High Temperature Acoustic Levitator (HAL) for containerless processing and property measurements at high temperatures; testing of the HAL module to establish this technology for use as a positioning device for microgravity uses; construction and evaluation of a brassboard hot wall Acoustic Levitation Furnace; construction and evaluation of a noncontact temperature measurement (NCTM) system based on AGEMA thermal imaging camera; construction of a prototype Division of Amplitude Polarimetric Pyrometer for NCTM of levitated specimens; evaluation of and recommendations for techniques to control contamination in containerless materials processing chambers; and evaluation of techniques for heating specimens to high temperatures for containerless materials experimentation.

Flow processes at low temperatures in ultrafine-grained aluminum

International Nuclear Information System (INIS)

Chinh, Nguyen Q.; Szommer, Peter; Csanadi, Tamas; Langdon, Terence G.

2006-01-01

Experiments were conducted to evaluate the flow behavior of pure aluminum at low temperatures. Samples were processed by equal-channel angular pressing (ECAP) to give a grain size of ∼1.2 μm and compression samples were cut from the as-pressed billets and tested over a range of strain rates at temperatures up to 473 K. The results show the occurrence of steady-state flow in these highly deformed samples and a detailed analysis gives a low strain rate sensitivity and an activation energy similar to the value for grain boundary diffusion. By using depth-sensing indentation testing and atomic force microscopy, it is shown that grain boundary sliding occurs in this material at low temperatures. This result is attributed to the presence of high-energy non-equilibrium boundaries in the severely deformed samples

Dual temperature isotope exchange process using hot feed with liquid recycle from the humidifier

International Nuclear Information System (INIS)

Paulis, G.J.C.A.

1977-01-01

This invention relates to an improvement in the dual temperature substances at two temperatures. It provides hot feed process, which while keeping the water purity advantages offered by a recycle of liquid, reduces the energy requirements of the process saving in capital cost over previous hot feed process, at equal production rate, or conversely which offers a substantial increase in production rate at equal capital costs

Sensitivity Studies of Advanced Reactors Coupled to High Temperature Electrolysis (HTE) Hydrogen Production Processes

International Nuclear Information System (INIS)

Edwin A. Harvego; Michael G. McKellar; James E. O'Brien; J. Stephen Herring

2007-01-01

High Temperature Electrolysis (HTE), when coupled to an advanced nuclear reactor capable of operating at reactor outlet temperatures of 800 C to 950 C, has the potential to efficiently produce the large quantities of hydrogen needed to meet future energy and transportation needs. To evaluate the potential benefits of nuclear-driven hydrogen production, the UniSim process analysis software was used to evaluate different reactor concepts coupled to a reference HTE process design concept. The reference HTE concept included an Intermediate Heat Exchanger and intermediate helium loop to separate the reactor primary system from the HTE process loops and additional heat exchangers to transfer reactor heat from the intermediate loop to the HTE process loops. The two process loops consisted of the water/steam loop feeding the cathode side of a HTE electrolysis stack, and the steam or air sweep loop used to remove oxygen from the anode side. The UniSim model of the process loops included pumps to circulate the working fluids and heat exchangers to recover heat from the oxygen and hydrogen product streams to improve the overall hydrogen production efficiencies. The reference HTE process loop model was coupled to separate UniSim models developed for three different advanced reactor concepts (a high-temperature helium cooled reactor concept and two different supercritical CO2 reactor concepts). Sensitivity studies were then performed to evaluate the affect of reactor outlet temperature on the power cycle efficiency and overall hydrogen production efficiency for each of the reactor power cycles. The results of these sensitivity studies showed that overall power cycle and hydrogen production efficiencies increased with reactor outlet temperature, but the power cycle producing the highest efficiencies varied depending on the temperature range considered

RDF gasification with water vapour: influence of process temperature on yield and products composition

International Nuclear Information System (INIS)

Galvagno, S.; Casciaro, G.; Russo, A.; Casu, S.; Martino, M.; Portofino, S.

2005-01-01

The opportunity of using RDF (Refused Derived Fuel) to produce fuel gas seems to be promising and particular attention has been focused on alternative process technologies such as pyrolysis and gasification. Within this frame, present work relates to experimental tests and obtained results of a series of experimental surveys on RDF gasification with water vapour, carried out by means of a bench scale rotary kiln plant at different process temperature, using thermogravimetry (TG) and infrared spectrometry (FTIR), in order to characterize the incoming material, and online gas chromatography to qualify the gaseous stream. Experimental data show that gas yield rise with temperature and, with respect to the gas composition, hydrogen content grows up mainly at the expense of the other gaseous compound, pointing out the major extension of secondary cracking reactions into the gaseous fraction at higher temperature. Syngas obtained at process temperature of 950 o C or higher seems to be suitable for fuel cells applications; at lower process temperature, gas composition suggest a final utilisation for feedstock recycling. The low organic content of solid residue does not suggest any other exploitation of the char apart from the land filling [it

Monitoring temperatures in coal conversion and combustion processes via ultrasound

Science.gov (United States)

Gopalsami, N.; Raptis, A. C.; Mulcahey, T. P.

1980-02-01

The state of the art of instrumentation for monitoring temperatures in coal conversion and combustion systems is examined. The instrumentation types studied include thermocouples, radiation pyrometers, and acoustical thermometers. The capabilities and limitations of each type are reviewed. A feasibility study of the ultrasonic thermometry is described. A mathematical model of a pulse-echo ultrasonic temperature measurement system is developed using linear system theory. The mathematical model lends itself to the adaptation of generalized correlation techniques for the estimation of propagation delays. Computer simulations are made to test the efficacy of the signal processing techniques for noise-free as well as noisy signals. Based on the theoretical study, acoustic techniques to measure temperature in reactors and combustors are feasible.

Behavior of mercury in high-temperature vitrification processes

International Nuclear Information System (INIS)

Goles, R.W.; Holton, K.K.; Sevigny, G.J.

1992-01-01

This paper reports that the Pacific Northwest Laboratory (PNL) has evaluated the waste processing behavior of mercury in simulated defense waste. A series of tests were performed under various operating conditions using an experimental-scale liquid-fed ceramic melter (LFCM). This solidification technology had no detectable capacity for incorporating mercury into its product, borosilicate glass. Chemically, the condensed mercury effluent was composed almost entirely of chlorides, and except in a low-temperature test, Hg 2 Cl 2 was the primary chloride formed. As a result, combined mercury accounted for most of the insoluble mass collected by the process quench scrubber. Although macroscopic quantities of elemental mercury were never observed in process secondary waste streams, finely divided and dispersed mercury that blackened all condensed Hg 2 Cl 2 residues was capable of saturating the quenched process exhaust with mercury vapor. The vapor pressure of mercury, however, in the quenched melter exhaust was easily and predictably controlled with the off-gas stream chiller

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

Assessment of very high-temperature reactors in process applications. Appendix II. VHTR process heat application studies

International Nuclear Information System (INIS)

Jones, J.E.; Gambill, W.R.; Cooper, R.H.; Fox, E.C.; Fuller, L.C.; Littlefield, C.C.; Silverman, M.D.

1977-06-01

A critical review is presented of the technology and economics for coupling a very high-temperature gas-cooled reactor to a variety of process applications. It is concluded that nuclear steam reforming of light hydrocarbons for coal conversion could be a near-term alternative and that direct nuclear coal gasification could be a future consideration. Thermochemical water splitting appears to be more costly and its availability farther in the future than the coal-conversion systems. Nuclear steelmaking is competitive with the direct reduction of iron ore from conventional coal-conversion processes but not competitive with the reforming of natural gas at present gas prices. Nuclear process heat for petroleum refining, even with the necessary backup systems, is competitive with fossil energy sources. The processing with nuclear heat of oil shale and tar sands is of marginal economic importance. An analysis of peaking power applications using nuclear heat was also made. It is concluded that steam reforming methane for energy storage and production of peaking power is not a viable economic alternative, but that energy storage with a high-temperature heat transfer salt (HTS) is competitive with conventional peaking systems. An examination of the materials required in process heat exchangers is made

Modeling Coupled THM Processes and Brine Migration in Salt at High Temperatures

International Nuclear Information System (INIS)

Rutqvist, Jonny; Blanco-Martin, Laura; Molins, Sergi; Trebotich, David; Birkholzer, Jens

2015-01-01

In this report, we present FY2015 progress by Lawrence Berkeley National Laboratory (LBNL) related to modeling of coupled thermal-hydrological-mechanical-chemical (THMC) processes in salt and their effect on brine migration at high temperatures. This is a combined milestone report related to milestone Salt R&D Milestone ''Modeling Coupled THM Processes and Brine Migration in Salt at High Temperatures'' (M3FT-15LB0818012) and the Salt Field Testing Milestone (M3FT-15LB0819022) to support the overall objectives of the salt field test planning.

Phycocyanin stability in microcapsules processed by spray drying method using different inlet temperature

Science.gov (United States)

Purnamayati, L.; Dewi, EN; Kurniasih, R. A.

2018-02-01

Phycocyanin is natural blue colorant which easily damages by heat. The inlet temperature of spray dryer is an important parameter representing the feature of the microcapsules.The aim of this study was to investigate the phycocyanin stability of microcapsules made from Spirulina sp with maltodextrin and κ-Carrageenan as the coating material, processed by spray drying method in different inlet temperature. Microcapsules were processed in three various inlet temperaturei.e. 90°C, 110°C, and 130°C, respectively. The results indicated that phycocyanin microcapsule with 90°C of inlet temperature produced the highest moisture content, phycocyanin concentration and encapsulation efficiency of 3,5%, 1,729% and 29,623%, respectively. On the other hand, the highest encapsulation yield was produced by 130°C of theinlet temperature of 29,48% and not significantly different with 110°C. The results of Scanning Electron Microscopy (SEM) showed that phycocyanin microcapsules with 110°C of inlet temperature produced the most rounded shape. To sum up, 110°C was the best inlet temperature to phycocyanin microencapsulation by the spray dryer.

Aerogel-Based Insulation for High-Temperature Industrial Processes

Energy Technology Data Exchange (ETDEWEB)

Dr. Owen Evans

2011-10-13

Under this program, Aspen Aerogels has developed an industrial insulation called Pyrogel HT, which is 4-5 times more thermally efficient than current non-aerogel technology. Derived from nanoporous silica aerogels, Pyrogel HT was specifically developed to address a high temperature capability gap not currently met with Aspen Aerogels{trademark} flagship product, Pyrogel XT. Pyrogel XT, which was originally developed on a separate DOE contract (DE-FG36-06GO16056), was primarily optimized for use in industrial steam processing systems, where application temperatures typically do not exceed 400 C. At the time, further improvements in thermal performance above 400 C could not be reasonably achieved for Pyrogel XT without significantly affecting other key material properties using the current technology. Cumulative sales of Pyrogel HT into domestic power plants should reach $125MM through 2030, eventually reaching about 10% of the total insulation market share in that space. Global energy savings would be expected to scale similarly. Over the same period, these sales would reduce domestic energy consumption by more than 65 TBtu. Upon branching out into all industrial processes in the 400 C-650 C regime, Pyrogel HT would reach annual sales levels of $150MM, with two-thirds of that being exported.

Relationship of electrical, magnetic, and mechanical properties to processing in high-temperature superconductors

International Nuclear Information System (INIS)

Blendell, J.E.; Chiang, C.K.; Cranmer, D.C.

1987-01-01

The interrelation between processing, microstructure, and properties is an important factor in understanding the behavior of ceramic materials. This type of understanding will be particularly important in the development of the new high T/sub c/ superconducting ceramic oxides of the type Ba/sub 2/YCu/sub 3/O/sub 7-x/. As an initial effort in understanding these relations, a number of properties have been measured for these superconducting ceramics and related to their microstructure and processing sequence. The Ba/sub 2/YCu/sub 3/O/sub 7-x/ ceramics were prepared by powder processing techniques, followed by dry pressing and sintering in both air and flowing oxygen at various temperatures. The sintered bodies were annealed at various temperatures and environments. Superconducting properties, such as the transition temperature and the width of the transition, were measured by both electrical conductivity and AC magnetic susceptibility; both of these properties show a strong sensitivity to annealing temperature and atmosphere. The microstructure and density were also strongly dependent on processing conditions. In this regard, compositional mapping proved to be an important technique for quantifying microstructural variations. Mechanical properties, such as elastic modulus, hardness, and fracture toughness, which will be important for the reliable use of these materials in large scale structures, were also determined

Highly conductive p-type amorphous oxides from low-temperature solution processing

International Nuclear Information System (INIS)

Li Jinwang; Tokumitsu, Eisuke; Koyano, Mikio; Mitani, Tadaoki; Shimoda, Tatsuya

2012-01-01

We report solution-processed, highly conductive (resistivity 1.3-3.8 mΩ cm), p-type amorphous A-B-O (A = Bi, Pb; B = Ru, Ir), processable at temperatures (down to 240 °C) that are compatible with plastic substrates. The film surfaces are smooth on the atomic scale. Bi-Ru-O was analyzed in detail. A small optical bandgap (0.2 eV) with a valence band maximum (VBM) below but very close to the Fermi level (binding energy E VBM = 0.04 eV) explains the high conductivity and suggests that they are degenerated semiconductors. The conductivity changes from three-dimensional to two-dimensional with decreasing temperature across 25 K.

Non-hoop winding effect on bonding temperature of laser assisted tape winding process

Science.gov (United States)

Zaami, Amin; Baran, Ismet; Akkerman, Remko

2018-05-01

One of the advanced methods for production of thermoplastic composite methods is laser assisted tape winding (LATW). Predicting the temperature in LATW process is very important since the temperature at nip-point (bonding line through width) plays a pivotal role in a proper bonding and hence the mechanical performance. Despite the hoop-winding where the nip-point is the straight line, non-hoop winding includes a curved nip-point line. Hence, the non-hoop winding causes somewhat a different power input through laser-rays and-reflections and consequently generates unknown complex temperature profile on the curved nip-point line. Investigating the temperature at the nip-point line is the point of interest in this study. In order to understand this effect, a numerical model is proposed to capture the effect of laser-rays and their reflections on the nip-point temperature. To this end, a 3D optical model considering the objects in LATW process is considered. Then, the power distribution (absorption and reflection) from the optical analysis is used as an input (heat flux distribution) for the thermal analysis. The thermal analysis employs a fully-implicit advection-diffusion model to calculate the temperature on the surfaces. The results are examined to demonstrate the effect of winding direction on the curved nip-point line (tape width) which has not been considered in literature up to now. Furthermore, the results can be used for designing a better and more efficient setup in the LATW process.

Steam gasification of waste tyre: Influence of process temperature on yield and product composition

Energy Technology Data Exchange (ETDEWEB)

Portofino, Sabrina, E-mail: sabrina.portofino@enea.it [UTTP NANO – C.R. ENEA Portici, P.le E. Fermi, 1 Loc. Granatello, 80055 Portici (Italy); Donatelli, Antonio; Iovane, Pierpaolo; Innella, Carolina; Civita, Rocco; Martino, Maria; Matera, Domenico Antonio; Russo, Antonio; Cornacchia, Giacinto [UTTTRI RIF – C.R. ENEA Trisaia, SS Jonica 106, km 419.5, 75026 Rotondella (Italy); Galvagno, Sergio [UTTP NANO – C.R. ENEA Portici, P.le E. Fermi, 1 Loc. Granatello, 80055 Portici (Italy)

2013-03-15

Highlights: ► Steam gasification of waste tyre as matter and energy recovery treatment. ► Process temperature affects products yield and gas composition. ► High temperature promotes hydrogen production. ► Char exploitation as activated carbon or carbon source. - Abstract: An experimental survey of waste tyre gasification with steam as oxidizing agent has been conducted in a continuous bench scale reactor, with the aim of studying the influence of the process temperature on the yield and the composition of the products; the tests have been performed at three different temperatures, in the range of 850–1000 °C, holding all the other operational parameters (pressure, carrier gas flow, solid residence time). The experimental results show that the process seems promising in view of obtaining a good quality syngas, indicating that a higher temperature results in a higher syngas production (86 wt%) and a lower char yield, due to an enhancement of the solid–gas phase reactions with the temperature. Higher temperatures clearly result in higher hydrogen concentrations: the hydrogen content rapidly increases, attaining values higher than 65% v/v, while methane and ethylene gradually decrease over the range of the temperatures; carbon monoxide and dioxide instead, after an initial increase, show a nearly constant concentration at 1000 °C. Furthermore, in regards to the elemental composition of the synthesis gas, as the temperature increases, the carbon content continuously decreases, while the oxygen content increases; the hydrogen, being the main component of the gas fraction and having a small atomic weight, is responsible for the progressive reduction of the gas density at higher temperature.

Temperature sensor realized by inkjet printing process on flexible substrate

International Nuclear Information System (INIS)

Dankoco, M.D.; Tesfay, G.Y.; Benevent, E.; Bendahan, M.

2016-01-01

Highlights: • Flexible temperature sensor was realized by inkjet printing process on Kapton substrate. • The jetting parameters were optimized to obtain evenly distributed silver coating layers and a large meander forming the sensor. • The Temperature sensor studied offers a good sensitivity, a good linearity and less than 5% hysteresis in extended measurement in the range of 20–60 °C. - Abstract: The objective of this study is to realize a printed and flexible temperature sensor to achieve surface temperature measurement of the human body. The sensor is a thermistor composed silver (Ag) deposited on a Polyimide substrate (Kapton HN). The meander was patterned by inkjet printing with a drop-on-demand Jetlab4 (Microfab Technologies Inc.). The resistance temperature coefficients have been studied in the temperature range of 20–60 °C with a range of voltage between 0 and 1 V. The stability versus time has also been measured without a sensor layer protection. The sensitive area of the sensor, silver lines width and the gap between the electrical conductors were, respectively 6.2 cm 2 , 300 μm, 60 μm. The mean temperature sensor sensitivity found was 2.23 × 10 −3 °C −1 . The results show a good linearity and less than 5% hysteresis in the extended measurement.

A CMOS high resolution, process/temperature variation tolerant RSSI for WIA-PA transceiver

International Nuclear Information System (INIS)

Yang Tao; Jiang Yu; Li Jie; Guo Jiangfei; Chen Hua; Han Jingyu; Guo Guiliang; Yan Yuepeng

2015-01-01

This paper presents a high resolution, process/temperature variation tolerant received signal strength indicator (RSSI) for wireless networks for industrial automation process automation (WIA-PA) transceiver fabricated in 0.18 μm CMOS technology. The active area of the RSSI is 0.24 mm 2 . Measurement results show that the proposed RSSI has a dynamic range more than 70 dB and the linearity error is within ±0.5 dB for an input power from −70 to 0 dBm (dBm to 50 Ω), the corresponding output voltage is from 0.81 to 1.657 V and the RSSI slope is 12.1 mV/dB while consuming all of 2 mA from a 1.8 V power supply. Furthermore, by the help of the integrated compensation circuit, the proposed RSSI shows the temperature error within ±1.5 dB from −40 to 85 °C, and process variation error within ±0.25 dB, which exhibits good temperature-independence and excellent robustness against process variation characteristics. (paper)

Assessment of very high-temperature reactors in process applications. Appendix III. Engineering evaluation of process heat applications for very-high temperature reactors

International Nuclear Information System (INIS)

Wiggins, D.S.; Williams, J.J.

1977-04-01

An engineering and economic evaluation is made of coal conversion processes that can be coupled to a very high-temperature nuclear reactor heat source. The basic system developed by General Atomic/Stone and Webster (GA/S and W) is similar to the H-coal process developed by Hydrocarbon Research, Inc., but is modified to accommodate a nuclear heat source and to produce synthetic natural gas (SNG), synthesis gas, and hydrogen in addition to synthetic crude liquids. The synthetic crude liquid production is analyzed by using the GA/S and W process coupled to either a nuclear- or fossil-heat source. Four other processes are included for comparison: (1) the Lurgi process for production of SNG, (2) the Koppers-Totzek process for production of either hydrogen or synthesis gas, (3) the Hygas process for production of SNG, and (4) the Westinghouse thermal-chemical water splitting process for production of hydrogen. The production of methanol and iron ore reduction are evaluated as two potential applications of synthesis gas from either the GA/S and W or Koppers-Totzek processes. The results indicate that the product costs for each of the gasification and liquefaction processes did not differ significantly, with the exception that the unproven Hygas process was cheaper and the Westinghouse process considerably more expensive than the others

A new approach to measure the temperature in rapid thermal processing

Science.gov (United States)

Yan, Jiang

This dissertation has presented the research work about a new method to measure the temperatures for the silicon wafer. The new technology is mainly for the rapid thermal processing (RTP) system. RTP is a promising technology in semiconductor manufacturing especially for the devices with minimum feature size less than 0.5 μm. The technique to measure the temperatures of the silicon wafer accurately is the key factor to apply the RTP technology to more critical processes in the manufacturing. Two methods which are mostly used nowadays, thermocouples and pyrometer, all have the limitation to be applied in the RTP. This is the motivation to study the new method using acoustic waves for the temperature measurement. The test system was designed and built up for the study of the acoustic method. The whole system mainly includes the transducer unit, circuit hardware, control software, the computer, and the chamber. The acoustic wave was generated by the PZT-5H transducer. The wave travels through the quartz rod into the silicon wafer. After traveling a certain distances in the wafer, the acoustic waves could be received by other transducers. By measuring the travel time and with the travel distance, the velocity of the acoustic wave traveling in the silicon wafer can be calculated. Because there is a relationship between the velocity and the temperature: the velocities of the acoustic waves traveling in the silicon wafer decrease as the temperatures of the wafer increase, the temperature of the wafer can be finally obtained. The thermocouples were used to check the measurement accuracy of the acoustic method. The temperature mapping across the 8″ silicon wafer was obtained with four transducer sensor unit. The temperatures of the wafer were measured using acoustic method at both static and dynamic status. The main purpose of the tests is to know the measurement accuracy for the new method. The goal of the research work regarding to the accuracy is acoustic method is

Low temperature hydrothermal processing of organic contaminants in Hanford tank waste

International Nuclear Information System (INIS)

Jones, E.O.; Pederson, L.R.; Freeman, H.D.; Schmidt, A.J.; Babad, H.

1993-02-01

Batch and continuous flow reactor tests at Pacific Northwest Laboratory (PNL) have shown that organics similar to those present in the single-shell and double-shell underground storage tanks at Hanford can be decomposed in the liquid phase at relatively mild temperatures of 150 degree C to 350 degree C in an aqueous process known as hydrothermal processing (HTP). The organics will react with the abundant oxidants such s nitrite already present in the Hanford tank waste to form hydrogen, carbon dioxide, methane, and ammonia. No air or oxygen needs to be added to the system. Ferrocyanides and free cyanide will hydrolyze at similar temperatures to produce formate and ammonia and may also react with nitrates or other oxides. During testing, the organic carbon was transformed first to oxalate at∼310 degree C and completely oxidized to carbonate at ∼350 degree C accompanied by hydroxide consumption. Solids were formed at higher temperatures, causing a small-diameter outlet tube to plug. The propensity for plugging was reduced by diluting the feed with concentrated hydroxide

Elevated Temperature, Notched Compression Performance of Out of Autoclave Processed Composites

Science.gov (United States)

Grimsley, Brian W.; Sutter, James K.; Dixon, Genevieve D.; Smeltzer, Satn S.

2013-01-01

Curved honeycomb sandwich panels composed of carbon fiber reinforced toughened-epoxy polymer facesheets are being evaluated for potential use as payload fairing components on the NASA heavy-lift space launch system (HL-SLS). These proposed composite sandwich panels provide the most efficient aerospace launch structures, and offer mass and thermal advantages when compared with existing metallic payload fairing structures. NASA and industry are investigating recently developed carbon fiber epoxy prepreg systems which can be fabricated using out-of autoclave (OOA) processes. Specifically, OOA processes using vacuum pressure in an oven and thereby significantly reducing the cost associated with manufacturing large (up to 10 m diameter) composite structures when compared with autoclave. One of these OOA composite material systems, CYCOM(R) 5320-1, was selected for manufacture of a 1/16th scale barrel portion of the payload fairing; such that, the system could be compared with the well-characterized prepreg system, CYCOM(R) 977-3, typically processed in an autoclave. Notched compression coupons for each material were obtained from the minimum-gauge flat laminate [60/-60/0]S witness panels produced in this manufacturing study. The coupons were also conditioned to an effective moisture equilibrium point and tested according to ASTM D6484M-09 at temperatures ranging from 25 C up to 177 C. The results of this elevated temperature mechanical characterization study demonstrate that, for thin coupons, the OHC strength of the OOA laminate was equivalent to the flight certified autoclave processed composite laminates; the limitations on the elevated temperature range are hot-wet conditions up to 163 C and are only within the margins of testing error. At 25 C, both the wet and dry OOA material coupons demonstrated greater OHC failure strengths than the autoclave processed material laminates. These results indicate a substantial improvement in OOA material development and

Shape Effect on the Temperature Field during Microwave Heating Process

Directory of Open Access Journals (Sweden)

Zhijun Zhang

2018-01-01

Full Text Available Aiming at improving the food quality during microwave process, this article mainly focused on the numerical simulation of shape effect, which was evaluated by microwave power absorption capability and temperature distribution uniformity in a single sample heated in a domestic microwave oven. This article only took the electromagnetic field and heat conduction in solid into consideration. The Maxwell equations were used to calculate the distribution of microwave electromagnetic field distribution in the microwave cavity and samples; then the electromagnetic energy was coupled as the heat source in the heat conduction process in samples. Quantitatively, the power absorption capability and temperature distribution uniformity were, respectively, described by power absorption efficiency (PAE and the statistical variation of coefficient (COV. In addition, we defined the comprehensive evaluation coefficient (CEC to describe the usability of a specific sample. In accordance with volume or the wave numbers and penetration numbers in the radial and axial directions of samples, they can be classified into different groups. And according to the PAE, COV, and CEC value and the specific need of microwave process, an optimal sample shape and orientation could be decided.

Low-Temperature Solution-Processed Gate Dielectrics for High-Performance Organic Thin Film Transistors

Directory of Open Access Journals (Sweden)

Jaekyun Kim

2015-10-01

Full Text Available A low-temperature solution-processed high-k gate dielectric layer for use in a high-performance solution-processed semiconducting polymer organic thin-film transistor (OTFT was demonstrated. Photochemical activation of sol-gel-derived AlOx films under 150 °C permitted the formation of a dense film with low leakage and relatively high dielectric-permittivity characteristics, which are almost comparable to the results yielded by the conventionally used vacuum deposition and high temperature annealing method. Octadecylphosphonic acid (ODPA self-assembled monolayer (SAM treatment of the AlOx was employed in order to realize high-performance (>0.4 cm2/Vs saturation mobility and low-operation-voltage (<5 V diketopyrrolopyrrole (DPP-based OTFTs on an ultra-thin polyimide film (3-μm thick. Thus, low-temperature photochemically-annealed solution-processed AlOx film with SAM layer is an attractive candidate as a dielectric-layer for use in high-performance organic TFTs operated at low voltages.

High pressure-temperature processing as an alternative for preserving basil

NARCIS (Netherlands)

Krebbers, B.; Matser, A.; Koets, M.; Bartels, P.; Berg, van den R.

2002-01-01

In this study the effect of sterilisation by high pressure (HP) on the quality of basil was compared to conventional processing techniques. By means of freezing, or blanching followed by drying, microbial reduction of spores was maximal one-log. Pulsed HP-temperature treatment yielded a reduction of

Development program for the high-temperature nuclear process heat system

International Nuclear Information System (INIS)

Jiacoletti, R.J.

1975-09-01

A comprehensive development program plan for a high-temperature nuclear process heat system with a very high temperature gas-cooled reactor heat source is presented. The system would provide an interim substitute for fossil-fired sources and ultimately the vehicle for the production of substitute and synthetic fuels to replace petroleum and natural gas. The dwindling domestic reserves of petroleum and natural gas dictate major increases in the utilization of coal and nuclear sources to meet the national energy demand. The nuclear process heat system has significant potential in a unique combination of the two sources that is environmentally and economically attractive and technically sound: the production of synthetic fuels from coal. In the longer term, it could be the key component in hydrogen production from water processes that offer a substitute fuel and chemical feedstock free of dependence on fossil-fuel reserves. The proposed development program is threefold: a process studies program, a demonstration plant program, and a supportive research and development program. Optional development scenarios are presented and evaluated, and a selection is proposed and qualified. The interdependence of the three major program elements is examined, but particular emphasis is placed on the supportive research and development activities. A detailed description of proposed activities in the supportive research and development program with tentative costs and schedules is presented as an appendix with an assessment of current status and planning

Aspects of nuclear process heat application of very high temperature reactors (VHTR)

International Nuclear Information System (INIS)

Jansing, W.T.; Kugeler, K.

2014-01-01

The different processes of high temperature process application require new concepts for heat exchangers to carry out key process like steam reforming of light hydrocarbons, gasification of coal or biomass, or thermo-chemical cycles for hydrogen production. These components have been tested in the German projects for high temperature development. The intention was always to test at original conditions of temperatures, pressures and gas atmospheres. Furthermore the time of testing should be long as possible, to be able to carry out extrapolations to the real lifetime of components. Partly test times of around 20 000 hours have been reached. Key components, which are discussed in this paper, are: Intermediate heat exchangers to separate the primary reactor side and the secondary process side. Here two components with a power of 10 MW have been tested with the result, that all requirements of a nuclear component with larger power (125 MW) can be fulfilled. The max. primary helium temperature was 950°C, the maximal secondary temperature was 900°C. These were components with helical wounded tubes and U-tubes. In the test facility KVK, which had been built to carry out many special tests on components for helium cycles, furthermore hot gas ducts (with large dimensions), hot gas valves (with large dimensions), steam generators (10 MW), helium circulators, the helium gas purification and special measurements installations for helium cycle have been tested. All these tests delivered a broad know how for the urther development of technologies using helium as working fluid. The total test time of KVK was longer than 20 000 h. In a large test facility for steam reforming (EVAⅡ10 MW, T He =950°C, p He =40 bar, T Reform =800°C) all technical details of the conversion process have been investigated and today the technical feasibility of this process is valuated as given. Two reformer bundles, one with baffles and one with separate guiding tubes for each reformer tube have

Processing temperature and moisture content effects on the texture and microscopic appearance of cooked fowl meat gels.

Science.gov (United States)

Voller, L M; Dawson, P L; Han, I Y

1996-12-01

New aseptic processes are being used and refined to produce convenient, shelf stable liquid products containing meat particles. These processes utilize high temperature, short time thermal treatments to minimize food quality change; however, little research has been conducted on the effects of this process on the texture of meat from mature hens traditionally used for canning. The objective of this study was to examine textural and structural changes in meat structure due to different high temperature (HT) heat treatments and meat moisture contents were examined by use of electron microscopy and torsion analyses. Cooked gels of different moisture contents (71.2 to 74.8%) were formulated from spent fowl breast meat and exposed to processing temperatures of 120 or 124 C. The HT processing resulted in stronger (tougher) meat gels that were more deformable (more chewy) than gels that were not processed by HT. Water added prior to cooking was not retained in samples that were cooked and then processed at 124 C, but was retained in the samples processed at 120 C. Electron micrographs showed a more organized and open gel structure in the samples with higher moisture content and lower temperature (120 C) processing compared to the lower moisture and higher (124 C) temperature treatments.

Effect of Temperature, Time, and Material Thickness on the Dehydration Process of Tomato

Directory of Open Access Journals (Sweden)

A. F. K. Correia

2015-01-01

Full Text Available This study aimed to evaluate the effects of temperature, time, and thickness of tomatoes fruits during adiabatic drying process. Dehydration, a simple and inexpensive process compared to other conservation methods, is widely used in the food industry in order to ensure a long shelf life for the product due to the low water activity. This study aimed to obtain the best processing conditions to avoid losses and keep product quality. Factorial design and surface response methodology were applied to fit predictive mathematical models. In the dehydration of tomatoes through the adiabatic process, temperature, time, and sample thickness, which greatly contribute to the physicochemical and sensory characteristics of the final product, were evaluated. The optimum drying conditions were 60°C with the lowest thickness level and shorter time.

Prediction of Proper Temperatures for the Hot Stamping Process Based on the Kinetics Models

Science.gov (United States)

Samadian, P.; Parsa, M. H.; Mirzadeh, H.

2015-02-01

Nowadays, the application of kinetics models for predicting microstructures of steels subjected to thermo-mechanical treatments has increased to minimize direct experimentation, which is costly and time consuming. In the current work, the final microstructures of AISI 4140 steel sheets after the hot stamping process were predicted using the Kirkaldy and Li kinetics models combined with new thermodynamically based models in order for the determination of the appropriate process temperatures. In this way, the effect of deformation during hot stamping on the Ae3, Acm, and Ae1 temperatures was considered, and then the equilibrium volume fractions of phases at different temperatures were calculated. Moreover, the ferrite transformation rate equations of the Kirkaldy and Li models were modified by a term proposed by Åkerström to consider the influence of plastic deformation. Results showed that the modified Kirkaldy model is satisfactory for the determination of appropriate austenitization temperatures for the hot stamping process of AISI 4140 steel sheets because of agreeable microstructure predictions in comparison with the experimental observations.

High temperature fluidized bed zero valent iron process for flue gas nitrogen monoxide removal

International Nuclear Information System (INIS)

Cheng, C.Y.; Chen, S.S.; Tang, C.H.; Chang, Y.M.; Cheng, H.H.; Liu, H.L.

2008-01-01

Nitrogen oxides (NO x ) are generated from a variety of sources, and are critical components of photochemical smog. Zero valent iron (ZVI) has been used to remove NO x in a number of studies. The ZVI process requires no extra chemicals or catalysts. In this study, a fluidized ZVI process for removing NO x from flue gases was proposed. The study examined the effects of temperature, ZVI dosage and influent NO concentrations, and observed the kinetic effects between the fluidized ZVI and NO x . A life cycle analysis of the process was also provided. The parametric analysis was conducted in a series of column studies using a continuous emissions monitoring system. Minimum fluidization velocity equations were provided, and the drag coefficient was determined. Capacities of ZVI for NO removal at different temperatures were calculated. Results of the study suggested that temperature, influent concentrations, and flow rates all influenced kinetic coefficients. Different temperatures resulted in different rates of NO removal. It was concluded that between 673 K and 773 K, almost complete NO removals were achieved. 14 refs., 2 tabs., 9 figs

High-temperature fermentation. How can processes for ethanol production at high temperatures become superior to the traditional process using mesophilic yeast?

Energy Technology Data Exchange (ETDEWEB)

Abdel-Banat, Babiker M.A.; Hoshida, Hisashi; Nonklang, Sanom; Akada, Rinji [Yamaguchi Univ. Graduate School of Medicine, Ube (Japan). Dept. of Applied Molecular Bioscience; Ano, Akihiko [Iwata Chemical Co. Ltd. (Japan)

2010-01-15

The process of ethanol fermentation has a long history in the production of alcoholic drinks, but much larger scale production of ethanol is now required to enable its use as a substituent of gasoline fuels at 3%, 10%, or 85% (referred to as E3, E10, and E85, respectively). Compared with fossil fuels, the production costs are a major issue for the production of fuel ethanol. There are a number of possible approaches to delivering cost-effective fuel ethanol production from different biomass sources, but we focus in our current report on high-temperature fermentation using a newly isolated thermotolerant strain of the yeast Kluyveromyces marxianus. We demonstrate that a 5 C increase only in the fermentation temperature can greatly affect the fuel ethanol production costs. We contend that this approach may also be applicable to the other microbial fermentations systems and propose that thermotolerant mesophilic microorganisms have considerable potential for the development of future fermentation technologies. (orig.)

Influence of annealing temperature on the Dy diffusion process in NdFeB magnets

Science.gov (United States)

Hu, Sheng-qing; Peng, Kun; Chen, Hong

2017-03-01

Sintered NdFeB magnets were coated with a layer of Dy metal using electron beam evaporation method and then annealed at various temperatures to investigate the temperature dependence of Dy diffusion process in NdFeB magnets. A Dy-rich phase was observed along the grain boundaries after the grain boundary diffusion process, the diffusion coefficients of various temperatures were obtained, the diffusion coefficients of Dy along the grain boundaries at 800 °C and 900 °C were determined to be 9.8×10-8 cm2 s-1 and 2.4×10-7 cm2 s-1, respectively. The diffusion length depended on the annealing temperature and the maximum diffusion length of approximately 1.8 mm and 3.0 mm can be obtained after annealing at 800 °C and 900 °C for 8 h. Higher diffusion temperature results in the diffusion not only along the grain boundaries but also into grains and then decrease in magnetic properties. The optimum annealing conditions can be determined as 900 °C for 8 h. The coercivity was improved from 1040 kA/m to 1450 kA/m and its magnetization has no significant reduction after the grain boundary diffusion process at the optimum annealing conditions.

High performance solution processed zirconium oxide gate dielectric appropriate for low temperature device application

Energy Technology Data Exchange (ETDEWEB)

Hasan, Musarrat; Nguyen, Manh-Cuong; Kim, Hyojin; You, Seung-Won; Jeon, Yoon-Seok; Tong, Duc-Tai; Lee, Dong-Hwi; Jeong, Jae Kyeong; Choi, Rino, E-mail: rino.choi@inha.ac.kr

2015-08-31

This paper reports a solution processed electrical device with zirconium oxide gate dielectric that was fabricated at a low enough temperature appropriate for flexible electronics. Both inorganic dielectric and channel materials were synthesized in the same organic solvent. The dielectric constant achieved was 13 at 250 °C with a reasonably low leakage current. The bottom gate transistor devices showed the highest mobility of 75 cm{sup 2}/V s. The device is operated at low voltage with high-k dielectric with excellent transconductance and low threshold voltage. Overall, the results highlight the potential of low temperature solution based deposition in fabricating more complicated circuits for a range of applications. - Highlights: • We develop a low temperature inorganic dielectric deposition process. • We fabricate oxide semiconductor channel devices using all-solution processes. • Same solvent is used for dielectric and oxide semiconductor deposition.

Process heat cogeneration using a high temperature reactor

International Nuclear Information System (INIS)

Alonso, Gustavo; Ramirez, Ramon; Valle, Edmundo del; Castillo, Rogelio

2014-01-01

Highlights: • HTR feasibility for process heat cogeneration is assessed. • A cogeneration coupling for HTR is proposed and process heat cost is evaluated. • A CCGT process heat cogeneration set up is also assessed. • Technical comparison between both sources of cogeneration is performed. • Economical competitiveness of the HTR for process heat cogeneration is analyzed. - Abstract: High temperature nuclear reactors offer the possibility to generate process heat that could be used in the oil industry, particularly in refineries for gasoline production. These technologies are still under development and none of them has shown how this can be possible and what will be the penalty in electricity generation to have this additional product and if the cost of this subproduct will be competitive with other alternatives. The current study assesses the likeliness of generating process heat from Pebble Bed Modular Reactor to be used for a refinery showing different plant balances and alternatives to produce and use that process heat. An actual practical example is presented to demonstrate the cogeneration viability using the fact that the PBMR is a modular small reactor where the cycle configuration to transport the heat of the reactor to the process plant plays an important role in the cycle efficiency and in the plant economics. The results of this study show that the PBMR would be most competitive when capital discount rates are low (5%), carbon prices are high (>30 US$/ton), and competing natural gas prices are at least 8 US$/mmBTU

Process heat cogeneration using a high temperature reactor

Energy Technology Data Exchange (ETDEWEB)

Alonso, Gustavo, E-mail: gustavoalonso3@gmail.com [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n, Ocoyoacac, Edo. De Mexico 52750 (Mexico); Instituto Politécnico Nacional, Unidad Profesional Adolfo Lopez Mateos, Ed. 9, Lindavista, D.F. 07300 (Mexico); Ramirez, Ramon [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n, Ocoyoacac, Edo. De Mexico 52750 (Mexico); Valle, Edmundo del [Instituto Politécnico Nacional, Unidad Profesional Adolfo Lopez Mateos, Ed. 9, Lindavista, D.F. 07300 (Mexico); Castillo, Rogelio [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n, Ocoyoacac, Edo. De Mexico 52750 (Mexico)

2014-12-15

Highlights: • HTR feasibility for process heat cogeneration is assessed. • A cogeneration coupling for HTR is proposed and process heat cost is evaluated. • A CCGT process heat cogeneration set up is also assessed. • Technical comparison between both sources of cogeneration is performed. • Economical competitiveness of the HTR for process heat cogeneration is analyzed. - Abstract: High temperature nuclear reactors offer the possibility to generate process heat that could be used in the oil industry, particularly in refineries for gasoline production. These technologies are still under development and none of them has shown how this can be possible and what will be the penalty in electricity generation to have this additional product and if the cost of this subproduct will be competitive with other alternatives. The current study assesses the likeliness of generating process heat from Pebble Bed Modular Reactor to be used for a refinery showing different plant balances and alternatives to produce and use that process heat. An actual practical example is presented to demonstrate the cogeneration viability using the fact that the PBMR is a modular small reactor where the cycle configuration to transport the heat of the reactor to the process plant plays an important role in the cycle efficiency and in the plant economics. The results of this study show that the PBMR would be most competitive when capital discount rates are low (5%), carbon prices are high (>30 US$/ton), and competing natural gas prices are at least 8 US$/mmBTU.

Development of rubber mixing process mathematical model and synthesis of control correction algorithm by process temperature mode using an artificial neural network

Directory of Open Access Journals (Sweden)

V. S. Kudryashov

2016-01-01

Full Text Available The article is devoted to the development of a correction control algorithm by temperature mode of a periodic rubber mixing process for JSC "Voronezh tire plant". The algorithm is designed to perform in the main controller a section of rubber mixing Siemens S7 CPU319F-3 PN/DP, which forms tasks for the local temperature controllers HESCH HE086 and Jumo dTRON304, operating by tempering stations. To compile the algorithm was performed a systematic analysis of rubber mixing process as an object of control and was developed a mathematical model of the process based on the heat balance equations describing the processes of heat transfer through the walls of technological devices, the change of coolant temperature and the temperature of the rubber compound mixing until discharge from the mixer chamber. Due to the complexity and nonlinearity of the control object – Rubber mixers and the availability of methods and a wide experience of this device control in an industrial environment, a correction algorithm is implemented on the basis of an artificial single-layer neural network and it provides the correction of tasks for local controllers on the cooling water temperature and air temperature in the workshop, which may vary considerably depending on the time of the year, and during prolonged operation of the equipment or its downtime. Tempering stations control is carried out by changing the flow of cold water from the cooler and on/off control of the heating elements. The analysis of the model experiments results and practical research at the main controller programming in the STEP 7 environment at the enterprise showed a decrease in the mixing time for different types of rubbers by reducing of heat transfer process control error.

Interaction processes between vacancies and dislocations in molybdenum in the temperature range around 0.3 of the melting temperature

International Nuclear Information System (INIS)

Zelada-Lambri, G.I.; Lambri, O.A.; Bozzano, P.B.; Garcia, J.A.; Celauro, C.A.

2008-01-01

Mechanical spectroscopy, electrical resistivity and transmission electron microscopy studies have been performed on pre-strained neutron irradiated single crystalline molybdenum in order to check the interaction processes between vacancies and dislocations in the temperature range between room temperature and 1273 K. The anelastic relaxation in molybdenum which appears between 800 K and 1273 K has been separated in two different physical mechanisms depending on the temperature of appearance of the relaxation peak. The physical mechanism which controls the damping peak appearing at around 800 K was related with the dragging of jogs by the dislocation under movement assisted by vacancy diffusion. The damping peak which appears at higher temperatures of about 1000 K was more consistent with the formation and diffusion of vacancies assisted by the dislocation movement

Interaction processes between vacancies and dislocations in molybdenum in the temperature range around 0.3 of the melting temperature

Energy Technology Data Exchange (ETDEWEB)

Zelada-Lambri, G.I. [Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Laboratorio de Materiales, Escuela de Ingenieria Electrica, Avenida Pellegrini 250, 2000 Rosario (Argentina); Lambri, O.A. [Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Laboratorio de Materiales, Escuela de Ingenieria Electrica, Avenida Pellegrini 250, 2000 Rosario (Argentina); Instituto de Fisica Rosario, Member of the CONICET' s Research Staff (Argentina)], E-mail: olambri@fceia.unr.edu.ar; Bozzano, P.B. [Laboratorio de Microscopia Electronica, Unidad de Actividad Materiales, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Avenida General Paz 1499, 1650 San Martin (Argentina); Garcia, J.A. [Departamento de Fisica Aplicada II, Facultad de Ciencias y Tecnologia, Universidad del Pais Vasco, Apartado 644, 48080 Bilbao, Pais Vasco (Spain); Celauro, C.A. [Reactor Nuclear RA-4, Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Riobamba y Berruti, 2000 Rosario (Argentina)

2008-10-15

Mechanical spectroscopy, electrical resistivity and transmission electron microscopy studies have been performed on pre-strained neutron irradiated single crystalline molybdenum in order to check the interaction processes between vacancies and dislocations in the temperature range between room temperature and 1273 K. The anelastic relaxation in molybdenum which appears between 800 K and 1273 K has been separated in two different physical mechanisms depending on the temperature of appearance of the relaxation peak. The physical mechanism which controls the damping peak appearing at around 800 K was related with the dragging of jogs by the dislocation under movement assisted by vacancy diffusion. The damping peak which appears at higher temperatures of about 1000 K was more consistent with the formation and diffusion of vacancies assisted by the dislocation movement.

Phase Stability Diagrams for High Temperature Corrosion Processes

Directory of Open Access Journals (Sweden)

J. J. Ramos-Hernandez

2013-01-01

Full Text Available Corrosion phenomena of metals by fused salts depend on chemical composition of the melt and environmental conditions of the system. Detail knowledge of chemistry and thermodynamic of aggressive species formed during the corrosion process is essential for a better understanding of materials degradation exposed to high temperature. When there is a lack of kinetic data for the corrosion processes, an alternative to understand the thermodynamic behavior of chemical species is to utilize phase stability diagrams. Nowadays, there are several specialized software programs to calculate phase stability diagrams. These programs are based on thermodynamics of chemical reactions. Using a thermodynamic data base allows the calculation of different types of phase diagrams. However, sometimes it is difficult to have access to such data bases. In this work, an alternative way to calculate phase stability diagrams is presented. The work is exemplified in the Na-V-S-O and Al-Na-V-S-O systems. This system was chosen because vanadium salts is one of the more aggressive system for all engineering alloys, especially in those processes where fossil fuels are used.

On improved understanding of plasma-chemical processes in complex low-temperature plasmas

Science.gov (United States)

Röpcke, Jürgen; Loffhagen, Detlef; von Wahl, Eric; Nave, Andy S. C.; Hamann, Stephan; van Helden, Jean-Piere H.; Lang, Norbert; Kersten, Holger

2018-05-01

Over the last years, chemical sensing using optical emission spectroscopy (OES) in the visible spectral range has been combined with methods of mid infrared laser absorption spectroscopy (MIR-LAS) in the molecular fingerprint region from 3 to 20 μm, which contains strong rotational-vibrational absorption bands of a large variety of gaseous species. This optical approach established powerful in situ diagnostic tools to study plasma-chemical processes of complex low-temperature plasmas. The methods of MIR-LAS enable to detect stable and transient molecular species in ground and excited states and to measure the concentrations and temperatures of reactive species in plasmas. Since kinetic processes are inherent to discharges ignited in molecular gases, high time resolution on sub-second timescales is frequently desired for fundamental studies as well as for process monitoring in applied research and industry. In addition to high sensitivity and good temporal resolution, the capacity for broad spectral coverage enabling multicomponent detection is further expanding the use of OES and MIR-LAS techniques. Based on selected examples, this paper reports on recent achievements in the understanding of complex low-temperature plasmas. Recently, a link with chemical modeling of the plasma has been provided, which is the ultimate objective for a better understanding of the chemical and reaction kinetic processes occurring in the plasma. Contribution to the Topical Issue "Fundamentals of Complex Plasmas", edited by Jürgen Meichsner, Michael Bonitz, Holger Fehske, Alexander Piel.

Effect of Temperature and Process on Quantity and Composition of Laboratory-generated Bitumen Emissions.

Science.gov (United States)

Bolliet, Christophe; Kriech, Anthony J; Juery, Catherine; Vaissiere, Mathieu; Brinton, Michael A; Osborn, Linda V

2015-01-01

In this study we investigated the impact of temperature on emissions as related to various bitumen applications and processes used in commercial products. Bitumen emissions are very complex and can be influenced in quantity and composition by differences in crude source, refining processes, application temperature, and work practices. This study provided a controlled laboratory environment to study five bitumen test materials from three European refineries; three paving grade, one used for primarily roofing and some paving applications, and one oxidized industrial specialty bitumen. Emissions were generated at temperatures between 140°C and 230°C based on typical application temperatures of each product. Emissions were characterized by aerodynamic particle size, total organic matter (TOM), simulated distillation, 40 individual PACs, and fluorescence (FL-PACs) spectroscopy. Results showed that composition of bitumen emissions is influenced by temperature under studied experimental conditions. A distinction between the oxidized bitumen with flux oil (industrial specialty bitumen) and the remaining bitumens was observed. Under typical temperatures used for paving (150°C-170°C), the TOM and PAC concentrations in the emissions were low. However, bitumen with flux oil produced significantly higher emissions at 230°C, laden with high levels of PACs. Flux oil in this bitumen mixture enhanced release of higher boiling-ranged compounds during application conditions. At 200°C and below, concentrations of 4-6 ring PACs were ≤6.51 μg/m(3) for all test materials, even when flux oil was used. Trends learned about emission temperature-process relationships from this study can be used to guide industry decisions to reduce worker exposure during processing and application of hot bitumen.

High Temperature Degradation of Powder-processed Ni-based Superalloy

Directory of Open Access Journals (Sweden)

Natália Luptáková

2015-05-01

Full Text Available The aim of present work is to study the high temperature degradation of the powder-processed polycrystalline superalloy Ni-15Cr-18Co-4Al-3.5Ti-5Mo. This superalloy has been applied as material for grips of a creep machine. The material was exposed at 1100 °C for about 10 days at 10 MPa stress. During the creep test occurred unacceptable creep deformation of grips as well as severe surface oxidation with scales peeling off. Three types of the microstructure were observed in the studied alloy: (i unexposed state; (ii heat treated (annealing - 10 min/1200 °C and (iii after using as a part of the equipment of the creep machine during the creep test. It is shown that the microstructure degradation resulting from the revealed γ´ phase fcc Ni3(Al,Ti particles preferentially created at the grain boundaries of the samples after performing creep tests affects mechanical properties of the alloy and represents a significant contribution to all degradation processes affecting performance and service life of the creep machine grips. Based on investigation and obtained results, the given material is not recommended to be used for grips of creep machine at temperatures above 1000 °C.

Air injection low temperature oxidation process for enhanced oil recovery from light oil reservoirs

International Nuclear Information System (INIS)

Tunio, A.H.; Harijan, K.

2010-01-01

This paper represents EOR (Enhanced Oil Recovery) methods to recover unswept oil from depleted light oil reservoirs. The essential theme here is the removal of oxygen at LTO (Low Temperature Oxidation) from the injected air for a light oil reservoir by means of some chemical reactions occurring between oil and oxygen. In-situ combustion process, HTO (High Temperature Oxidation) is not suitable for deep light oil reservoirs. In case of light oil reservoirs LTO is more suitable to prevail as comparative to HTO. Few laboratory experimental results were obtained from air injection process, to study the LTO reactions. LTO process is suitable for air injection rate in which reservoir has sufficiently high temperature and spontaneous reaction takes place. Out comes of this study are the effect of LTO reactions in oxygen consumption and the recovery of oil. This air injection method is economic compared to other EOR methods i.e. miscible hydrocarbon gas, nitrogen, and carbon dioxide flooding etc. This LTO air injection process is suitable for secondary recovery methods where water flooding is not feasible due to technical problems. (author)

Preparation of (Bi, Pb)-2223/Ag tapes by high temperature sintering and post-annealing process

DEFF Research Database (Denmark)

Hua, L.; Grivel, Jean-Claude; Andersen, L.G.

2002-01-01

A novel heat treatment process was developed to fabricate (Bi, Pb)-2223/Ag tapes with high critical current density (J(c)). The process can be divided into two parts: reformation and post-annealing. Tapes were first heated to the maximum temperature (830-860 degreesC) followed by slow cooling...... (reformation). Then, tape, were annealed between 760 and 820 degreesC (post-annealing). Reformation is expected to produce a large amount of liquid phase which may heat microcracks, decrease porosity, and improve grain growth. However, since the sintering temperature is beyond the Bi-2223 single-phase region......-energy synchrotron XRD and SEM/EDX. Some process parameters e.g. sintering temperature. cooling rate. and post-annealing time were optimised. (C) 2002 Elsevier Science B.V. All rights reserved....

Analysis of the process of raising the temperature in the spark channel at a discharge in gas

CERN Document Server

Korytchenko, K V; Chumakov, V I

2001-01-01

Analysis of the process of raising the temperature in the spark channel at a discharge in gas is performed. The quantitative evaluation was made in main for the air. The effect of steadying a thermodynamic equilibrium in gas,as well as the influence of power discharge parameters on the process of temperature increasing was analyzed. The quantitative evaluation of time parameters of the processes of rotary, oscillatory relaxation, dissociation and ionization has allowed to reveal the influence of each of them on temperature increasing in the spark channel. The problems arising in the course of practical realization of a spark discharge which influence on the process of temperature raising are detected,and the ways for their solution are determined. The results obtained can be put in a basis of developing the methods to design devices for intensive increase of temperatures in gas media using the electrical discharge,as well as for analysis of a dependence of shock wave intensity on dynamic parameters of the ele...

A cross-coupled-structure-based temperature sensor with reduced process variation sensitivity

Energy Technology Data Exchange (ETDEWEB)

Tie Meng; Cheng Xu, E-mail: tiemeng@mprc.pku.edu.c [Microprocessor Research and Development Center, Peking University, Beijing 100871 (China)

2009-04-15

An innovative, thermally-insensitive phenomenon of cascaded cross-coupled structures is found. And a novel CMOS temperature sensor based on a cross-coupled structure is proposed. This sensor consists of two different ring oscillators. The first ring oscillator generates pulses that have a period, changing linearly with temperature. Instead of using the system clock like in traditional sensors, the second oscillator utilizes a cascaded cross-coupled structure to generate temperature independent pulses to capture the result from the first oscillator. Due to the compensation between the two ring oscillators, errors caused by supply voltage variations and systematic process variations are reduced. The layout design of the sensor is based on the TSMC13G process standard cell library. Only three inverters are modified for proper channel width tuning without any other custom design. This allows for an easy integration of the sensor into cell-based chips. Post-layout simulations results show that an error lower than +-1.1 deg. C can be achieved in the full temperature range from -40 to 120 deg. C. As shown by SPICE simulations, the thermal insensitivity of the cross-coupled inverters can be realized for various TSMC technologies: 0.25 mum, 0.18 mum, 0.13 mum, and 65 nm.

Effect of temperature on the anodizing process of aluminum alloy AA 5052

Science.gov (United States)

Theohari, S.; Kontogeorgou, Ch.

2013-11-01

The effect of temperature (10-40 °C) during the anodizing process of AA 5052 for 40 min in 175 g/L sulfuric acid solution at constant voltage (15 V) was studied in comparison with pure aluminum. The incorporated magnesium species in the barrier layer result in the further increase of the minimum current density passed during anodizing, as the temperature increases, by about 42% up to 30 °C and then by 12% up to 40 °C. Then during the anodizing process for 40 min a blocking effect on oxide film growth was gradually observed as the temperature increased until 30 °C. The results of EDAX analysis on thick films reveal that the mean amount of the magnesium species inside the film is about 50-70% less than that in the bulk alloy, while it is higher at certain locations adjacent to the film surface at 30 °C. The increase of anodizing temperature does not influence the porosity of thin films (formed for short times) on pure aluminum, while it reduces it on the alloy. At 40 °C the above mentioned blocking effects disappear. It means that the presence of magnesium species causes an impediment to the effect of temperature on iss, on the film thickness and on the porosity of thin films, only under conditions where film growth takes place without significant loss of the anodizing charge to side reactions.

The Effect of Process and Model Parameters in Temperature Prediction for Hot Stamping of Boron Steel

Directory of Open Access Journals (Sweden)

Chaoyang Sun

2013-01-01

Full Text Available Finite element models of the hot stamping and cold die quenching process for boron steel sheet were developed using either rigid or elastic tools. The effect of tool elasticity and process parameters on workpiece temperature was investigated. Heat transfer coefficient between blank and tools was modelled as a function of gap and contact pressure. Temperature distribution and thermal history in the blank were predicted, and thickness distribution of the blank was obtained. Tests were carried out and the test results are used for the validation of numerical predictions. The effect of holding load and the size of cooling ducts on temperature distribution during the forming and the cool die quenching process was also studied by using two models. The results show that higher accuracy predictions of blank thickness and temperature distribution during deformation were obtained using the elastic tool model. However, temperature results obtained using the rigid tool model were close to those using the elastic tool model for a range of holding load.

Antarctic Temperature Extremes from MODIS Land Surface Temperatures: New Processing Methods Reveal Data Quality Puzzles

Science.gov (United States)

Grant, G.; Gallaher, D. W.

2017-12-01

New methods for processing massive remotely sensed datasets are used to evaluate Antarctic land surface temperature (LST) extremes. Data from the MODIS/Terra sensor (Collection 6) provides a twice-daily look at Antarctic LSTs over a 17 year period, at a higher spatiotemporal resolution than past studies. Using a data condensation process that creates databases of anomalous values, our processes create statistical images of Antarctic LSTs. In general, the results find few significant trends in extremes; however, they do reveal a puzzling picture of inconsistent cloud detection and possible systemic errors, perhaps due to viewing geometry. Cloud discrimination shows a distinct jump in clear-sky detections starting in 2011, and LSTs around the South Pole exhibit a circular cooling pattern, which may also be related to cloud contamination. Possible root causes are discussed. Ongoing investigations seek to determine whether the results are a natural phenomenon or, as seems likely, the results of sensor degradation or processing artefacts. If the unusual LST patterns or cloud detection discontinuities are natural, they point to new, interesting processes on the Antarctic continent. If the data artefacts are artificial, MODIS LST users should be alerted to the potential issues.

Temperature control for high pressure processes up to 1400 MPa

International Nuclear Information System (INIS)

Reineke, K; Mathys, A; Knorr, D; Heinz, V

2008-01-01

Pressure- assisted sterilisation is an emerging technology. Hydrostatic high pressure can reduce the thermal load of the product and this allows quality retention in food products. To guarantee the safety of the sterilisation process it is necessary to investigate inactivation kinetics especially of bacterial spores. A significant roll during the inactivation of microorganisms under high pressure has the thermodynamic effect of the adiabatic heating. To analyse the individual effect of pressure and temperature on microorganism inactivation an exact temperature control of the sample to reach ideal adiabatic conditions and isothermal dwell times is necessary. Hence a heating/cooling block for a high pressure unit (Stansted Mini-Food-lab; high pressure capillary with 300 μL sample volume) was constructed. Without temperature control the sample would be cooled down during pressure built up, because of the non-adiabatic heating of the steel made vessel. The heating/cooling block allows an ideal adiabatic heat up and cooling of the pressure vessel during compression and decompression. The high pressure unit has a pressure build-up rate up to 250 MPa s -1 and a maximum pressure of 1400 MPa. Sebacate acid was chosen as pressure transmitting medium because it had no phase shift over the investigate pressure and temperature range. To eliminate the temperature difference between sample and vessel during compression and decompression phase, the mathematical model of the adiabatic heating/cooling of water and sebacate acid was implemented into a computational routine, written in Test Point. The calculated temperature is the setpoint of the PID controller for the heating/cooling block. This software allows an online measurement of the pressure and temperature in the vessel and the temperature at the outer wall of the vessel. The accurate temperature control, including the model of the adiabatic heating opens up the possibility to realise an ideal adiabatic heating and cooling

Batch statistical process control of a fluid bed granulation process using in-line spatial filter velocimetry and product temperature measurements.

Science.gov (United States)

Burggraeve, A; Van den Kerkhof, T; Hellings, M; Remon, J P; Vervaet, C; De Beer, T

2011-04-18

Fluid bed granulation is a batch process, which is characterized by the processing of raw materials for a predefined period of time, consisting of a fixed spraying phase and a subsequent drying period. The present study shows the multivariate statistical modeling and control of a fluid bed granulation process based on in-line particle size distribution (PSD) measurements (using spatial filter velocimetry) combined with continuous product temperature registration using a partial least squares (PLS) approach. Via the continuous in-line monitoring of the PSD and product temperature during granulation of various reference batches, a statistical batch model was developed allowing the real-time evaluation and acceptance or rejection of future batches. Continuously monitored PSD and product temperature process data of 10 reference batches (X-data) were used to develop a reference batch PLS model, regressing the X-data versus the batch process time (Y-data). Two PLS components captured 98.8% of the variation in the X-data block. Score control charts in which the average batch trajectory and upper and lower control limits are displayed were developed. Next, these control charts were used to monitor 4 new test batches in real-time and to immediately detect any deviations from the expected batch trajectory. By real-time evaluation of new batches using the developed control charts and by computation of contribution plots of deviating process behavior at a certain time point, batch losses or reprocessing can be prevented. Immediately after batch completion, all PSD and product temperature information (i.e., a batch progress fingerprint) was used to estimate some granule properties (density and flowability) at an early stage, which can improve batch release time. Individual PLS models relating the computed scores (X) of the reference PLS model (based on the 10 reference batches) and the density, respectively, flowabililty as Y-matrix, were developed. The scores of the 4 test

Low-Temperature Solution Processable Electrodes for Piezoelectric Sensors Applications

Science.gov (United States)

Tuukkanen, Sampo; Julin, Tuomas; Rantanen, Ville; Zakrzewski, Mari; Moilanen, Pasi; Lupo, Donald

2013-05-01

Piezoelectric thin-film sensors are suitable for a wide range of applications from physiological measurements to industrial monitoring systems. The use of flexible materials in combination with high-throughput printing technologies enables cost-effective manufacturing of custom-designed, highly integratable piezoelectric sensors. This type of sensor can, for instance, improve industrial process control or enable the embedding of ubiquitous sensors in our living environment to improve quality of life. Here, we discuss the benefits, challenges and potential applications of piezoelectric thin-film sensors. The piezoelectric sensor elements are fabricated by printing electrodes on both sides of unmetallized poly(vinylidene fluoride) film. We show that materials which are solution processable in low temperatures, biocompatible and environmental friendly are suitable for use as electrode materials in piezoelectric sensors.

Temperature Field Simulation of Powder Sintering Process with ANSYS

Science.gov (United States)

He, Hongxiu; Wang, Jun; Li, Shuting; Chen, Zhilong; Sun, Jinfeng; You, Ying

2018-03-01

Aiming at the “spheroidization phenomenon” in the laser sintering of metal powder and other quality problems of the forming parts due to the thermal effect, the finite element model of the three-dimensional transient metal powder was established by using the atomized iron powder as the research object. The simulation of the mobile heat source was realized by means of parametric design. The distribution of the temperature field during the sintering process under different laser power and different spot sizes was simulated by ANSYS software under the condition of fully considering the influence of heat conduction, thermal convection, thermal radiation and thermophysical parameters. The influence of these factors on the actual sintering process was also analyzed, which provides an effective way for forming quality control.

High temperature reactor and application to nuclear process heat

Energy Technology Data Exchange (ETDEWEB)

Schulten, R; Kugeler, K [Kernforschungsanlage Juelich G.m.b.H. (Germany, F.R.)

1976-01-01

The principle of high temperature nuclear process heat is explained and the main applications (hydrogasification of coal, nuclear chemical heat pipe, direct reduction of iron ore, coal gasification by steam and water splitting) are described in more detail. The motivation for the introduction of nuclear process heat to the market, questions of cost, of raw material resources and environmental aspects are the next point of discussion. The new technological questions of the nuclear reactor and the status of development are described, especially information about the fuel elements, the hot gas ducts, the contamination and some design considerations are added. Furthermore the status of development of helium heated steam reformers, the main results of the work until now and the further activities in this field are explained.

Implementing high-temperature short-time media treatment in commercial-scale cell culture manufacturing processes.

Science.gov (United States)

Pohlscheidt, Michael; Charaniya, Salim; Kulenovic, Fikret; Corrales, Mahalia; Shiratori, Masaru; Bourret, Justin; Meier, Steven; Fallon, Eric; Kiss, Robert

2014-04-01

The production of therapeutic proteins by mammalian cell culture is complex and sets high requirements for process, facility, and equipment design, as well as rigorous regulatory and quality standards. One particular point of concern and significant risk to supply chain is the susceptibility to contamination such as bacteria, fungi, mycoplasma, and viruses. Several technologies have been developed to create barriers for these agents to enter the process, e.g. filtration, UV inactivation, and temperature inactivation. However, if not implemented during development of the manufacturing process, these types of process changes can have significant impact on process performance if not managed appropriately. This article describes the implementation of the high-temperature short-time (HTST) treatment of cell culture media as an additional safety barrier against adventitious agents during the transfer of a large-scale commercial cell culture manufacturing process. The necessary steps and experiments, as well as subsequent results during qualification runs and routine manufacturing, are shown.

Analysis of prompt supercritical process with heat transfer and temperature feedback

Institute of Scientific and Technical Information of China (English)

ZHU BO; ZHU Qian; CHEN Zhiyun

2009-01-01

The prompt supercritical process of a nuclear reactor with temperature feedback and initial power as well as heat transfer with a big step reactivity (ρ0>β) is analyzed in this paper.Considering the effect of heat transfer on temperature of the reactor,a new model is set up.For any initial power,the variations of output power and reactivity with time are obtained by numerical method.The effects of the big inserted step reactivity and initial power on the prompt supercritical process are analyzed and discussed.It was found that the effect of heat transfer on the output power and reactivity can be neglected under any initial power,and the output power obtained by the adiabatic model is basically in accordance with that by the model of this paper,and the analytical solution can be adopted.The results provide a theoretical base for safety analysis and operation management of a power reactor.

Effect of process parameters on temperature distribution in twin-electrode TIG coupling arc

International Nuclear Information System (INIS)

Zhang, Guangjun; Xiong, Jun; Gao, Hongming; Wu, Lin

2012-01-01

The twin-electrode TIG coupling arc is a new type of welding heat source, which is generated in a single welding torch that has two tungsten electrodes insulated from each other. This paper aims at determining the distribution of temperature for the coupling arc using the Fowler–Milne method under the assumption of local thermodynamic equilibrium. The influences of welding current, arc length, and distance between both electrode tips on temperature distribution of the coupling arc were analyzed. Based on the results, a better understanding of the twin-electrode TIG welding process was obtained. -- Highlights: ► Increasing arc current will increase the coupling arc temperature. ► Arc length seldom affects the peak temperature of the coupling arc. ► Increasing arc length will increase the extension of temperature near the anode. ► Increasing distance will decrease temperatures in the central part of the arc.

Fiber‐optic distributed temperature sensing: A new tool for assessment and monitoring of hydrologic processes

Science.gov (United States)

Lane, John W.; Day-Lewis, Frederick D.; Johnson, Carole D.; Dawson, Cian B.; Nelms, David L.; Miller, Cheryl; Wheeler, Jerrod D.; Harvey, Charles F.; Karam, Hanan N.

2008-01-01

Fiber‐optic distributed temperature sensing (FO DTS) is an emerging technology for characterizing and monitoring a wide range of important earth processes. FO DTS utilizes laser light to measure temperature along the entire length of standard telecommunications optical fibers. The technology can measure temperature every meter over FO cables up to 30 kilometers (km) long. Commercially available systems can measure fiber temperature as often as 4 times per minute, with thermal precision ranging from 0.1 to 0.01 °C depending on measurement integration time. In 2006, the U.S. Geological Survey initiated a project to demonstrate and evaluate DTS as a technology to support hydrologic studies. This paper demonstrates the potential of the technology to assess and monitor hydrologic processes through case‐study examples of FO DTS monitoring of stream‐aquifer interaction on the Shenandoah River near Locke's Mill, Virginia, and on Fish Creek, near Jackson Hole, Wyoming, and estuary‐aquifer interaction on Waquoit Bay, Falmouth, Massachusetts. The ability to continuously observe temperature over large spatial scales with high spatial and temporal resolution provides a new opportunity to observe and monitor a wide range of hydrologic processes with application to other disciplines including hazards, climate‐change, and ecosystem monitoring.

Effects of holding pressure and process temperatures on the mechanical properties of moulded metallic parts

DEFF Research Database (Denmark)

Islam, Aminul; Hansen, Hans Nørgaard; Esteves, N.M.

2013-01-01

Metal injection moulding is gaining more and more importance over the time and needs more research to be done to understand the sensitivity of process to different process parameters. The current paper makes an attempt to better understand the effects of holding pressure and process temperatures...... on the moulded metallic parts. Stainless steel 316L is used in the investigation to produce the specimen by metal injection moulding (MIM) and multiple analyses were carried out on samples produced with different combinations of holding pressure, mould temperature and melt temperature. Finally, the parts were...... characterized to investigate mechanical properties like density, ultimate tensile strength, shrinkage etc. The results are discussed in the paper. The main conclusion from this study is unlike plastic moulding, the tensile properties of MIM parts doesn’t vary based on the flow direction of the melt, and tensile...

High temperature heat exchanger application in power engineering and energy-technological processes

International Nuclear Information System (INIS)

Shpilrain, E.E.

1986-01-01

The possibilities for intensification of various processes in metallurgy and chemical technology, the prospects for enhancing power plant efficiency are often linked with temperature increase of reagents, heat carriers and working fluids. In some cases elevated temperatures give the opportunity to use new and principally different technologies, enhance capacities of power production units and technological apparatuses, improve their economical performance. The variety of problems where high temperature heat exchangers are or can be used are extremely wide. It is therefore impossible to overview all of them in one lecture. Therefore the author tries to consider only some examples which are typical and gives an impression of what kind of problems arise in these cases

Low-temperature process steps for realization of non-volatile memory devices

NARCIS (Netherlands)

Brunets, I.; Boogaard, A.; Aarnink, Antonius A.I.; Kovalgin, Alexeij Y.; Wolters, Robertus A.M.; Holleman, J.; Schmitz, Jurriaan

2007-01-01

In this work, the low-temperature process steps required for the realization of nano-crystal non-volatile memory cells are discussed. An amorphous silicon film, crystallized using a diode pumped solid state green laser irradiating at 532 nm, is proposed as an active layer. The deposition of the

An Integrated, Low Temperature Process to Capture and Sequester Carbon Dioxide from Industrial Emissions

Science.gov (United States)

Wendlandt, R. F.; Foremski, J. J.

2013-12-01

Laboratory experiments show that it is possible to integrate (1) the chemistry of serpentine dissolution, (2) capture of CO2 gas from the combustion of natural gas and coal-fired power plants using aqueous amine-based solvents, (3) long-term CO2 sequestration via solid phase carbonate precipitation, and (4) capture solvent regeneration with acid recycling in a single, continuous process. In our process, magnesium is released from serpentine at 300°C via heat treatment with ammonium sulfate salts or at temperatures as low as 50°C via reaction with sulfuric acid. We have also demonstrated that various solid carbonate phases can be precipitated directly from aqueous amine-based (NH3, MEA, DMEA) CO2 capture solvent solutions at room temperature. Direct precipitation from the capture solvent enables regenerating CO2 capture solvent without the need for heat and without the need to compress the CO2 off gas. We propose that known low-temperature electrochemical methods can be integrated with this process to regenerate the aqueous amine capture solvent and recycle acid for dissolution of magnesium-bearing mineral feedstocks and magnesium release. Although the direct precipitation of magnesite at ambient conditions remains elusive, experimental results demonstrate that at temperatures ranging from 20°C to 60°C, either nesquehonite Mg(HCO3)(OH)●2H2O or a double salt with the formula [NH4]2Mg(CO3)2●4H2O or an amorphous magnesium carbonate precipitate directly from the capture solvent. These phases are less desirable for CO2 sequestration than magnesite because they potentially remove constituents (water, ammonia) from the reaction system, reducing the overall efficiency of the sequestration process. Accordingly, the integrated process can be accomplished with minimal energy consumption and loss of CO2 capture and acid solvents, and a net generation of 1 to 4 moles of H2O/6 moles of CO2 sequestered (depending on the solid carbonate precipitate and amount of produced H2

Plasma flow reactor for steady state monitoring of physical and chemical processes at high temperatures.

Science.gov (United States)

Koroglu, Batikan; Mehl, Marco; Armstrong, Michael R; Crowhurst, Jonathan C; Weisz, David G; Zaug, Joseph M; Dai, Zurong; Radousky, Harry B; Chernov, Alex; Ramon, Erick; Stavrou, Elissaios; Knight, Kim; Fabris, Andrea L; Cappelli, Mark A; Rose, Timothy P

2017-09-01

We present the development of a steady state plasma flow reactor to investigate gas phase physical and chemical processes that occur at high temperature (1000 flow injector). We have modeled the system using computational fluid dynamics simulations that are bounded by measured temperatures. In situ line-of-sight optical emission and absorption spectroscopy have been used to determine the structures and concentrations of molecules formed during rapid cooling of reactants after they pass through the plasma. Emission spectroscopy also enables us to determine the temperatures at which these dynamic processes occur. A sample collection probe inserted from the open end of the reactor is used to collect condensed materials and analyze them ex situ using electron microscopy. The preliminary results of two separate investigations involving the condensation of metal oxides and chemical kinetics of high-temperature gas reactions are discussed.

High-temperature gas-cooled reactors and process heat

International Nuclear Information System (INIS)

Kasten, P.R.

1980-01-01

High-Temperature Gas-Cooled Reactors (HTGRs) are fueled with ceramic-coated microspheres of uranium and thorium oxides/carbides embedded in graphite blocks which are cooled with helium. Promising areas of HTGR application are in cogeneration, energy transport using Heat Transfer Salt, recovery of oils from oil shale, steam reforming of methane for chemical production, coal gasification, and in energy transfer using chemical heat jpipes in the long term. Further, HTGRs could be used as the energy source for hydrogen production through thermochemical water splitting in the long term. The potential market for Process Heat HTGRs is 100-200 large units by about the year 2020

Low Temperature Processed Complementary Metal Oxide Semiconductor (CMOS) Device by Oxidation Effect from Capping Layer

KAUST Repository

Wang, Zhenwei; Al-Jawhari, Hala A.; Nayak, Pradipta K.; Caraveo-Frescas, J. A.; Wei, Nini; Hedhili, Mohamed N.; Alshareef, Husam N.

2015-01-01

, which is significantly lower than the temperature generally required to form tin dioxide. Based on this approach, CMOS inverters based entirely on tin oxide TFTs were fabricated. Our method provides a solution to lower the process temperature for tin

Report on process design studies of a tritium recovery process using dual temperature exchange with metal hydrides

International Nuclear Information System (INIS)

Benenati, R.F.

1976-01-01

Studies were made of the process characteristics of a plant to decontaminate tritiated water using dual temperature exchange with VH 2 . Feed to the plant consists of 300 kg/day on water containing 1 Ci/kg of tritium. A reference design was developed based on a decontamination factor of 10 2 and 10 kg/day of enriched product. This design requires a total of 48 ideal separation stages, 22 stages in the enriching section and 26 stages in the stripping section. Only low grade heat is required for the heating cycle and a relatively small (12 ton) ice machine is required for the cooling cycle. A total plant inventory of approximately 10 tons VH 2 is required. A mechanical design of the dual temperature stage complete with all heat transfer surfaces and flow diverters was devised and modeled. Since the process involves periodic swings in temperature between 0 and 60 0 C, a substantial portion of the operation is expected to be in unsteady state transition from one state to another. A two-step experimental program has been presented: the first step consists of a single stage unit, i.e., one hot bed and one cold bed operating in a simple closed loop. The second stage in the experimental program would consist of five stages operating as a small cascade

Limit of grain refinement during ECAP process. Temperature influence

International Nuclear Information System (INIS)

Chuvil'deev, V.N.; Kopylov, V.I.; Nokhrin, A.V.; Makarov, I.M.; Lopatin, Yu.G.

2004-01-01

Experimental and theoretical study results are reported for the process of deformation grain refinement under severe plastic deformation. A generalization is made for experimental study results on deformation dispersing of unalloyed metals and aluminium and magnesium base alloys. The model is built that allows calculating the value of minimum grain size attained by the method of equal-channel angular pressing. The expressions are derived which describe the dependence of grain refinement limit on the nature of material and the temperature of severe plastic deformation [ru

Assessing the processing quality of different potato cultivars during storage at various temperatures

International Nuclear Information System (INIS)

Amjad, A.; Randhawa, M.A.; Butt, M.S.; Asghar, M.

2016-01-01

Processing industry needs continuous supply of tubers for fries/chips preparation throughout the year. Storage is obligatory to meet the increasing demand of population. Objective of this study was to evaluate the processing and quality characteristics of different potato cultivars (Lady Rosetta, Sante, Hermes, Crozo, Kuroda and Asterix) during storage with 75-80 percent relative humidity for the period of 160 days at various temperatures (3 degree C, 7 degree C, 11 degree C). Quality parameters such as specific gravity, sprouting, weight loss, dry matter, starch content, ascorbic acid, sugar content and invertase enzyme activity were determined to estimate the processing potential of each cultivar. High Performance Liquid Chromatography (HPLC) equipped with amino (NH2) column and Refractive Index Detector (RID) was used for the identification and quantification of sugars. The findings of the present work showed that temperature significantly (p Hermes > Crozo > Sante > Asterix > Kuroda. (author)

Low-Cost Bio-Based Carbon Fibers for High Temperature Processing

Energy Technology Data Exchange (ETDEWEB)

Paul, Ryan Michael [GrafTech International, Brooklyn Heights, OH (United States); Naskar, Amit [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-08-03

GrafTech International Holdings Inc. (GTI), under Award No. DE-EE0005779, worked with Oak Ridge National Laboratory (ORNL) under CRADA No. NFE-15-05807 to develop lignin-based carbon fiber (LBCF) technology and to demonstrate LBCF performance in high-temperature products and applications. This work was unique and different from other reported LBCF work in that this study was application-focused and scalability-focused. Accordingly, the executed work was based on meeting criteria based on technology development, cost, and application suitability. High-temperature carbon fiber based insulation is used in energy intensive industries, such as metal heat treating and ceramic and semiconductor material production. Insulation plays a critical role in achieving high thermal and process efficiency, which is directly related to energy usage, cost, and product competitiveness. Current high temperature insulation is made with petroleum based carbon fibers, and one goal of this protect was to develop and demonstrate an alternative lignin (biomass) based carbon fiber that would achieve lower cost, CO2 emissions, and energy consumption and result in insulation that met or exceeded the thermal efficiency of current commercial insulation. In addition, other products were targeted to be evaluated with LBCF. As the project was designed to proceed in stages, the initial focus of this work was to demonstrate lab-scale LBCF from at least 4 different lignin precursor feedstock sources that could meet the estimated production cost of $5.00/pound and have ash level of less than 500 ppm in the carbonized insulation-grade fiber. Accordingly, a preliminary cost model was developed based on publicly available information. The team demonstrated that 4 lignin samples met the cost criteria. In addition, the ash level for the 4 carbonized lignin samples was below 500 ppm. Processing as-received lignin to produce a high purity lignin fiber was a significant accomplishment in that most industrial

Modeling of a Large-Scale High Temperature Regenerative Sulfur Removal Process

DEFF Research Database (Denmark)

Konttinen, Jukka T.; Johnsson, Jan Erik

1999-01-01

model that does not account for bed hydrodynamics. The pilot-scale test run results, obtained in the test runs of the sulfur removal process with real coal gasifier gas, have been used for parameter estimation. The validity of the reactor model for commercial-scale design applications is discussed.......Regenerable mixed metal oxide sorbents are prime candidates for the removal of hydrogen sulfide from hot gasifier gas in the simplified integrated gasification combined cycle (IGCC) process. As part of the regenerative sulfur removal process development, reactor models are needed for scale......-up. Steady-state kinetic reactor models are needed for reactor sizing, and dynamic models can be used for process control design and operator training. The regenerative sulfur removal process to be studied in this paper consists of two side-by-side fluidized bed reactors operating at temperatures of 400...

Effects of Processing Temperatures of Nickel Plating on Capacitance Density of Alumina Film Capacitor.

Science.gov (United States)

Jeong, Myung-Sun; Ju, Byeong-Kwon; Lee, Jeon-Kook

2015-06-01

We observed the effects of nickel plating temperatures for controlling the surface morphologies of the deposited nickel layers on the alumina nano-pores. The alumina nano-channels were filled with nickel at various processing temperatures of 60-90 degrees C. The electrical properties of the alumina film capacitors were changed with processing temperatures. The electroless nickel plating (ENP) at 60 degrees C improved the nickel penetration into the alumina nano-channels due to the reduced reaction rate. Nickel layers are uniformly formed on the high aspect ratio alumina pores. Due to the uniform nickel electrode, the capacitance density of the alumina film capacitors is improved by the low leakage current, dissipation factor and equivalent series resistance. Alumina film capacitors made by ENP at 60 degrees C had a high capacitance density of 160 nF/cm2.

Design of the steam reformer for the HTR-10 high temperature process heat application

International Nuclear Information System (INIS)

Ju Huaiming; Xu Yuanhui; Jia Haijun

2000-01-01

The 10 MW High Temperature Reactor Test Module (HTR-10) is being constructed now and planned to be operational in 2000. One of the objectives is to develop the high temperature process heat application. The methane steam reformer is one of the key-facilities for the nuclear process heat application system. The paper describes the conceptual design of the HTR-10 Steam Reformer with He heating, and the design optimization computer code. It can be used to perform sensitivity analysis for parameters, and to improve the design. Principal parameters and construction features of the HTR-10 reformer heated by He are introduced. (author)

Catalyzed deuterium-deuterium and deuterium-tritium fusion blankets for high temperature process heat production

International Nuclear Information System (INIS)

Ragheb, M.M.H.; Salimi, B.

1982-01-01

Tritiumless blanket designs, associated with a catalyzed deuterium-deuterium (D-D) fusion cycle and using a single high temperature solid pebble or falling bed zone, for process heat production, are proposed. Neutronics and photonics calculations, using the Monte Carlo method, show that an about 90% heat deposition fraction is possible in the high temperature zone, compared to a 30 to 40% fraction if a deuterium-tritium (D-T) fusion cycle is used with separate breeding and heat deposition zones. Such a design is intended primarily for synthetic fuels manufacture through hydrogen production using high temperature water electrolysis. A system analysis involving plant energy balances and accounting for the different fusion energy partitions into neutrons and charged particles showed that plasma amplification factors in the range of 2 are needed. In terms of maximization of process heat and electricity production, and the maximization of the ratio of high temperature process heat to electricity, the catalyzed D-D system outperforms the D-T one by about 20%. The concept is thought competitive to the lithium boiler concept for such applications, with the added potential advantages of lower tritium inventories in the plasma, reduced lithium pumping (in the case of magnetic confinement) and safety problems, less radiation damage at the first wall, and minimized risks of radioactive product contamination by tritium

THE DYEING PROCESS OF KNITTED FABRICS AT DIFFERENT TEMPERATURES USING ULTRASOUND

Directory of Open Access Journals (Sweden)

MITIC Jelena

2014-05-01

Full Text Available The dyeing of knitted fabrics made from 100 % cellulose using on-line procedure vinyl sulfonic reactive dye, with or without ultrasound energy, is carried out in this paper. The impact of temperature has been observed. The dye exhaustion is monitored using the method of absorption spectrophotometry, and the quality control of the coloration is monitored using color measurements. The acting of ultrasound on coloration consistency, as well as on some mechanical characteristics has also been examined. All examples of the ultrasound dyeing process show greater dye exhaustion in comparison to the conventional procedure. In addition, all the samples, which have been dyed with the ultrasound energy at 40°C, are significantly darker and have deeper color in comparison with the referent sample. The temperature has a great influence on kinetic energy of the dye molecules, and therefore on the diffusion processes in the dyeing system. The exhaustion chart indicates that when the temperature is lower the exhaustion degree drops. However, all the samples dyed with the ultrasound energy have bigger exhaustion. Besides that, ultrasound energy contributes to warming up the processing environment, so the additional warm up with the electricity is unnecessary, unlike the conventional way of dyeing. Since the reactive dyes chemically connect themselves with the cellulose substrate and in that way form covalent connection, the dyed fabrics have good washing consistency. Analysis results indicate that the consistencies are identical regardless the applied dyeing procedure. In other words, the dyeing method using the ultrasound energy produces the dyed fabric of the same quality. After analyzing the results of breaking force and elongation at break of knitted fabrics, it is noticeable that there is no degradation of previously mentioned knitted fabrics features (horizontally and vertically during the ultrasound wave’s activity.

Advanced processing of high temperature P/M copper alloy for aerospace applications

International Nuclear Information System (INIS)

Raman, R.V.; Rele, S.V.; Lasley, C.C.; Krotz, P.D.

1991-01-01

Copper Alloy 1035 is a rapidly solidified Cu-Cr-Zr alloy developed by Pratt and Whitney, which exhibits good elevated temperature strength and thermal conductivity. RSR Alloy 1035 powder has been consolidated utilizing the patented Ceracon Process. The Ceracon Process is a quasi-isostatic, hot consolidation technique which utilizes a proprietary particulate material as a pressure transmitting medium in place of a gas media as used in HIPping. Measured mechanical properties to 1200 F are compared to materials consolidated via vacuum plasma spraying (VPS), or VPS + HIPping processes. Advantages and disadvantages of these processing techniques are compared. Porosity and microstructural features are also evaluated

Wave Characteristics of Temperature Inversion Process of Nighttime Radiation,

Science.gov (United States)

1983-12-09

CHARACTERISTICS OF TEMPERATURE INVERSION PROCESS OF NIGHTTIME RADIATION By: Zhou Mingyu and Zhang ¥i English pages: 8 Source: Kexue Tongbao, 1982, pp. 156...lJournal of Meteorology], 39 (1981), 1:70-81. 3. Drazin, P. G., J. Fluid. Mech., 4 (1958), 214-224. 4. Zhou Mingyu et al., QIXIANG XUEBAO, 38 (1980), 3: 250...258. 5. Emnanuel, C. B., B-L. Meteor., 5(1973), N(1/2)8 19-27. 6. Zhou Mingyu et al., J. Acoust. Soc., A. m., 68 (1980), 1: 303-308. 8 I iI

Effects of Processing Temperature on Color Properties of Dry-Cured Hams Made without Nitrite

Directory of Open Access Journals (Sweden)

Giovanni Parolari

2016-04-01

Full Text Available Dry cured hams were investigated for their ability to develop red color even at low temperature (3–4 °C and in the absence of added nitrites; results were compared with those obtained from nitrite-free hams made at conventional warm maturing temperatures. Colorimetric parameters (L*, a*, b*, and hue and concentration of the main pigments Zn protoporphyrin IX (ZnPP and heme were measured at three stages of preparation (six, nine, and 12 months, showing that red color was successfully formed at low temperatures, though at a slower rate and less intensively than under warm conditions. Major differences in the pattern of color development were found with the two processing temperatures. While the typical features of an enzyme-dependent mechanism, with a progressive drop in enzyme activity paralleling the synthesis of Zn protoporphyrin IX, were observed at warm temperatures, the same did not occur in cold-made hams, where the enzyme activity was almost unchanged throughout the process. These results, along with data from a descriptive sensory analysis, are supportive of a non-enzymatic mechanism leading to ZnPP (hence the red color under cold conditions, with an estimated three-month delay compared with nitrite-free hams manufactured in a warm maturing regimen.

Effects of Processing Temperature on Color Properties of Dry-Cured Hams Made without Nitrite.

Science.gov (United States)

Parolari, Giovanni; Aguzzoni, Agnese; Toscani, Tania

2016-04-29

Dry cured hams were investigated for their ability to develop red color even at low temperature (3-4 °C) and in the absence of added nitrites; results were compared with those obtained from nitrite-free hams made at conventional warm maturing temperatures. Colorimetric parameters (L*, a*, b*, and hue) and concentration of the main pigments Zn protoporphyrin IX (ZnPP) and heme were measured at three stages of preparation (six, nine, and 12 months), showing that red color was successfully formed at low temperatures, though at a slower rate and less intensively than under warm conditions. Major differences in the pattern of color development were found with the two processing temperatures. While the typical features of an enzyme-dependent mechanism, with a progressive drop in enzyme activity paralleling the synthesis of Zn protoporphyrin IX, were observed at warm temperatures, the same did not occur in cold-made hams, where the enzyme activity was almost unchanged throughout the process. These results, along with data from a descriptive sensory analysis, are supportive of a non-enzymatic mechanism leading to ZnPP (hence the red color) under cold conditions, with an estimated three-month delay compared with nitrite-free hams manufactured in a warm maturing regimen.

Effects of Processing Temperature on Color Properties of Dry-Cured Hams Made without Nitrite

Science.gov (United States)

Parolari, Giovanni; Aguzzoni, Agnese; Toscani, Tania

2016-01-01

Dry cured hams were investigated for their ability to develop red color even at low temperature (3–4 °C) and in the absence of added nitrites; results were compared with those obtained from nitrite-free hams made at conventional warm maturing temperatures. Colorimetric parameters (L*, a*, b*, and hue) and concentration of the main pigments Zn protoporphyrin IX (ZnPP) and heme were measured at three stages of preparation (six, nine, and 12 months), showing that red color was successfully formed at low temperatures, though at a slower rate and less intensively than under warm conditions. Major differences in the pattern of color development were found with the two processing temperatures. While the typical features of an enzyme-dependent mechanism, with a progressive drop in enzyme activity paralleling the synthesis of Zn protoporphyrin IX, were observed at warm temperatures, the same did not occur in cold-made hams, where the enzyme activity was almost unchanged throughout the process. These results, along with data from a descriptive sensory analysis, are supportive of a non-enzymatic mechanism leading to ZnPP (hence the red color) under cold conditions, with an estimated three-month delay compared with nitrite-free hams manufactured in a warm maturing regimen. PMID:28231128

Development and processing temperature dependence of ferromagnetism in Zn0.98Co0.02O

International Nuclear Information System (INIS)

Hays, J.; Thurber, A.; Reddy, K. M.; Punnoose, A.; Engelhard, M. H.

2006-01-01

We report the development of room-temperature ferromagnetism (FM), with coercivity H c =2000 Oe and saturation magnetization M s ∼0.01 emu/g, in chemically synthesized powders of Zn 0.98 Co 0.02 O processed at 150 deg. C, and paramagnetism with antiferromagnetic interactions between the Co 2+ spins (S=3/2) in samples processed at higher temperatures 200≤T P ≤900 deg. C. X-ray diffraction data show a decrease in the lattice parameters a and c with T P , indicating a progressive incorporation of 0.58A sized tetrahedral Co 2+ at the substitutional sites of 0.60 A sized Zn 2+ . Diffuse reflectance spectra show three well defined absorption edges at 660, 615, and 568 nm due to the d-d crystal field transitions 4 A 2 (F)→ 2 E(G), 4 A 2 (F)→ 4 T 1 (P), and 4 A 2 (F)→ 2 T 1 (G) of high spin (S=3/2)Co 2+ in a tetrahedral crystal field, whose intensities increase with processing temperature. X-ray photoelectron spectroscopy shows that the doped Co 2+ ions in the 150 deg. C processed samples are located mostly on the surface of the particles and they disperse into the entire volume of the particles when processed at higher temperatures. The observations suggest that the FM most likely results from Co 2+ attached to the surface sites and it is lost in well dispersed samples formed at T P >150 deg. C

Clofibric acid degradation in UV254/H2O2 process: effect of temperature.

Science.gov (United States)

Li, Wenzhen; Lu, Shuguang; Qiu, Zhaofu; Lin, Kuangfei

2010-04-15

The degradation of clofibric acid (CA) in UV(254)/H(2)O(2) process under three temperature ranges, i.e. T1 (9.0-11.5 degrees C), T2 (19.0-21.0 degrees C) and T3 (29.0-30.0 degrees C) was investigated. The effects of solution constituents including NO(3)(-) and HCO(3)(-) anions, and humic acid (HA) on CA degradation were evaluated in Milli-Q waters. CA degradation behaviors were simulated with the pseudo-first-order kinetic model and the apparent rate constant (k(ap)) and half-life time (t(1/2)) were calculated. The results showed that higher temperature would favor CA degradation, and CA degradation was taken place mostly by indirect oxidation through the formation of OH radicals in UV(254)/H(2)O(2) process. In addition, the effects of both NO(3)(-) and HCO(3)(-) anions at two selected concentrations (1.0x10(-3) and 0.1 mol L(-1)) and HA (20 mg L(-1)) on CA degradation were investigated. The results showed that HA had negative effect on CA degradation, and this effect was much more apparent under low temperature condition. On the other hand, the inhibitive effect on CA degradation at both lower and higher concentrations of bicarbonate was observed, and this inhibitive effect was much more apparent at higher bicarbonate concentration and lower temperature condition. While, at higher nitrate concentration the inhibitive effect on CA degradation under three temperature ranges was observed, and with the temperature increase this negative effect was apparently weakened. However, at lower nitrate concentration a slightly positive effect on CA degradation was found under T2 and T3 conditions. Moreover, when using a real wastewater treatment plant (WWTP) effluent spiked with CA over 99% of CA removal could be achieved under 30 degrees C within only 15 min compared with 40 and 80 min under 20 and 10 degrees C respectively, suggesting a significant promotion in CA degradation under higher temperature condition. Therefore, it can be concluded that temperature plays an

76 FR 81363 - Temperature-Indicating Devices; Thermally Processed Low-Acid Foods Packaged in Hermetically...

Science.gov (United States)

2011-12-28

... amended FDA's regulations for thermally processed low-acid foods packaged in hermetically sealed... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration 21 CFR Part 113 [Docket No. FDA-2007-N-0265] (formerly 2007N-0026) Temperature-Indicating Devices; Thermally Processed Low-Acid...

High temperature corrosion in the service environments of a nuclear process heat plant

International Nuclear Information System (INIS)

Quadakkers, W.J.

1987-01-01

In a nuclear process heat plant the heat-exchanging components fabricated from nickel- and Fe-Ni-based alloys are subjected to corrosive service environments at temperatures up to 950 0 C for service lives of up to 140 000 h. In this paper the corrosion behaviour of the high temperature alloys in the different service environments will be described. It is shown that the degree of protection provided by Cr 2 O 3 -based surface oxide scales against carburization and decarburization of the alloys is primarily determined not by the oxidation potential of the atmospheres but by a dynamic process involving, on the one hand, the oxidizing gas species and the metal and, on the other hand, the carbon in the alloy and the oxide scale. (orig.)

High temperature and dynamic testing of AHSS for an analytical description of the adiabatic cutting process

Science.gov (United States)

Winter, S.; Schmitz, F.; Clausmeyer, T.; Tekkaya, A. E.; F-X Wagner, M.

2017-03-01

In the automotive industry, advanced high strength steels (AHSS) are widely used as sheet part components to reduce weight, even though this leads to several challenges. The demand for high-quality shear cutting surfaces that do not require reworking can be fulfilled by adiabatic shear cutting: High strain rates and local temperatures lead to the formation of adiabatic shear bands (ASB). While this process is well suited to produce AHSS parts with excellent cutting surface quality, a fundamental understanding of the process is still missing today. In this study, compression tests in a Split-Hopkinson Pressure Bar with an initial strain rate of 1000 s-1 were performed in a temperature range between 200 °C and 1000 °C. The experimental results show that high strength steels with nearly the same mechanical properties at RT may possess a considerably different behavior at higher temperatures. The resulting microstructures after testing at different temperatures were analyzed by optical microscopy. The thermo-mechanical material behavior was then considered in an analytical model. To predict the local temperature increase that occurs during the adiabatic blanking process, experimentally determined flow curves were used. Furthermore, the influence of temperature evolution with respect to phase transformation is discussed. This study contributes to a more complete understanding of the relevant microstructural and thermo-mechanical mechanisms leading to the evolution of ASB during cutting of AHSS.

The Merkel coefficient and its dependence on the temperature position of the cooling tower process

International Nuclear Information System (INIS)

Klenke, W.

1977-01-01

The Merkel coefficient, or evaporation coefficient, is still being used as a characteristic factor for the cooling tower process. Its dependence on the cooling range or on the warm water temperature of the process is often considered a disadvantage of the theory of evaporation cooling. This is also the reason for the suggestion to change the theory in such a way that the Merkel coefficient becomes independent of the temperature. The present investigation, however, leads to the result that the dependence of the Merkel coefficient on the temperature must be considered as a remarkable confirmation for the evidence of the theory of heat and mass transfer, as the experimental statements agree fully with the results of the theoretical considerations. (orig.) [de

The INNOHYP-CA Project: producing Hydrogen by innovative high-temperature processes

International Nuclear Information System (INIS)

Giaconia, A.; Giorgiantoni, G.; Liberatore, R.; Tarquini, P.; Vignolini, M.

2008-01-01

The Project, financed under the 6. Framework Programme, has selected a member of innovative high-temperature processes that seem promising for large-scale production of Hydrogen. ENEA has contributed to the analysis of the status of national and regional projects in the European countries and to the definition of guidelines for the future development of these technologies [it

Sterilization of liquid foods by pulsed electric fields–an innovative ultra-high temperature process

Science.gov (United States)

Reineke, Kai; Schottroff, Felix; Meneses, Nicolas; Knorr, Dietrich

2015-01-01

The intention of this study was to investigate the inactivation of endospores by a combined thermal and pulsed electric field (PEF) treatment. Therefore, self-cultivated spores of Bacillus subtilis and commercial Geobacillus stearothermophilus spores with certified heat resistance were utilized. Spores of both strains were suspended in saline water (5.3 mS cm−1), skim milk (0.3% fat; 5.3 mS cm−1) and fresh prepared carrot juice (7.73 mS cm−1). The combination of moderate preheating (70–90°C) and an insulated PEF-chamber, combined with a holding tube (65 cm) and a heat exchanger for cooling, enabled a rapid heat up to 105–140°C (measured above the PEF chamber) within 92.2–368.9 μs. To compare the PEF process with a pure thermal inactivation, each spore suspension was heat treated in thin glass capillaries and D-values from 90 to 130°C and its corresponding z-values were calculated. For a comparison of the inactivation data, F-values for the temperature fields of both processes were calculated by using computational fluid dynamics (CFD). A preheating of saline water to 70°C with a flow rate of 5 l h−1, a frequency of 150 Hz and an energy input of 226.5 kJ kg−1, resulted in a measured outlet temperature of 117°C and a 4.67 log10 inactivation of B. subtilis. The thermal process with identical F-value caused only a 3.71 log10 inactivation. This synergism of moderate preheating and PEF was even more pronounced for G. stearothermophilus spores in saline water. A preheating to 95°C and an energy input of 144 kJ kg−1 resulted in an outlet temperature of 126°C and a 3.28 log10 inactivation, whereas nearly no inactivation (0.2 log10) was achieved during the thermal treatment. Hence, the PEF technology was evaluated as an alternative ultra-high temperature process. However, for an industrial scale application of this process for sterilization, optimization of the treatment chamber design is needed to reduce the occurring inhomogeneous temperature

Sterilization of liquid foods by pulsed electric fields-an innovative ultra-high temperature process.

Science.gov (United States)

Reineke, Kai; Schottroff, Felix; Meneses, Nicolas; Knorr, Dietrich

2015-01-01

The intention of this study was to investigate the inactivation of endospores by a combined thermal and pulsed electric field (PEF) treatment. Therefore, self-cultivated spores of Bacillus subtilis and commercial Geobacillus stearothermophilus spores with certified heat resistance were utilized. Spores of both strains were suspended in saline water (5.3 mS cm(-1)), skim milk (0.3% fat; 5.3 mS cm(-1)) and fresh prepared carrot juice (7.73 mS cm(-1)). The combination of moderate preheating (70-90°C) and an insulated PEF-chamber, combined with a holding tube (65 cm) and a heat exchanger for cooling, enabled a rapid heat up to 105-140°C (measured above the PEF chamber) within 92.2-368.9 μs. To compare the PEF process with a pure thermal inactivation, each spore suspension was heat treated in thin glass capillaries and D-values from 90 to 130°C and its corresponding z-values were calculated. For a comparison of the inactivation data, F-values for the temperature fields of both processes were calculated by using computational fluid dynamics (CFD). A preheating of saline water to 70°C with a flow rate of 5 l h(-1), a frequency of 150 Hz and an energy input of 226.5 kJ kg(-1), resulted in a measured outlet temperature of 117°C and a 4.67 log10 inactivation of B. subtilis. The thermal process with identical F-value caused only a 3.71 log10 inactivation. This synergism of moderate preheating and PEF was even more pronounced for G. stearothermophilus spores in saline water. A preheating to 95°C and an energy input of 144 kJ kg(-1) resulted in an outlet temperature of 126°C and a 3.28 log10 inactivation, whereas nearly no inactivation (0.2 log10) was achieved during the thermal treatment. Hence, the PEF technology was evaluated as an alternative ultra-high temperature process. However, for an industrial scale application of this process for sterilization, optimization of the treatment chamber design is needed to reduce the occurring inhomogeneous temperature fields.

Influence of annealing temperature on the Dy diffusion process in NdFeB magnets

Energy Technology Data Exchange (ETDEWEB)

Hu, Sheng-qing, E-mail: joy_hsq@126.com [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Peng, Kun, E-mail: kpeng@hnu.edu.cn [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Chen, Hong [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China)

2017-03-15

Sintered NdFeB magnets were coated with a layer of Dy metal using electron beam evaporation method and then annealed at various temperatures to investigate the temperature dependence of Dy diffusion process in NdFeB magnets. A Dy-rich phase was observed along the grain boundaries after the grain boundary diffusion process, the diffusion coefficients of various temperatures were obtained, the diffusion coefficients of Dy along the grain boundaries at 800 °C and 900 °C were determined to be 9.8×10{sup −8} cm{sup 2} s{sup −1} and 2.4×10{sup −7} cm{sup 2} s{sup −1}, respectively. The diffusion length depended on the annealing temperature and the maximum diffusion length of approximately 1.8 mm and 3.0 mm can be obtained after annealing at 800 °C and 900 °C for 8 h. Higher diffusion temperature results in the diffusion not only along the grain boundaries but also into grains and then decrease in magnetic properties. The optimum annealing conditions can be determined as 900 °C for 8 h. The coercivity was improved from 1040 kA/m to 1450 kA/m and its magnetization has no significant reduction after the grain boundary diffusion process at the optimum annealing conditions. - Highlights: • The optimum annealing conditions can be determined as 900 °C for 8 h. • The diffusion coefficient of Dy at 900 °Care determined to be 2.4×10{sup −7} cm{sup 2} s{sup −1}. • A maximum diffusion length of about 3 mm can be obtained.

Hydration of Rhyolitic Glasses: Comparison Between High- and Low-Temperature Processes

Science.gov (United States)

Anovitz, L.; Fayek, M.; Cole, D. R.; Carter, T.

2012-12-01

While a great deal is known about the interaction between water and rhyolitic glasses and melts at temperatures above the glass transition, the nature of this interaction at lower temperatures is more obscure. Comparisons between high- and low-temperature diffusive studies suggest that several factors play an important role under lower-temperatures conditions that are not significant at higher temperatures. Surface concentrations, which equilibrate quickly at high temperature, change far more slowly as temperatures decrease, and may not equilibrate at room temperature for hundreds or thousands of years. Coupled with temperature-dependent diffusion coefficients this complicates calculation of diffusion profiles as a function of time. A key factor in this process appears to be the inability of "self-stress", caused by the in-diffusing species, to relax at lower temperatures, a result expected below the glass transition. Regions of the glass hydrated at low temperatures are strongly optically anisotropic, and preliminary calculations suggest that the magnitude of stress involved may be very high. On the microstuctural scale, extrapolations of high-temperature FTIR data to lower temperatures suggests there should be little or no hydroxyl present in glasses "hydrated" at low temperatures. Analyses of both block and powder samples suggest that this is generally true in the bulk of the hydrated glass, excluding hydroxyl groups that formed during the initial cooling of the melt. However, hydroxyl do groups appear to be present at the glass surface, where both SIMS and neutron reflectometry data suggest hydration levels may be higher than projected from the bulk of the glass. Isotopic exchange experiments also suggest that bonding is relatively weak, as hydration water exchanges readily with the enviroment. All of these observations lead to the conclusion that the observed stress is due to the presence of interstructural, rather than bonded, water. This likely explains the

Analysis of the kinetics of decohesion process in the conditions of cyclic temperature variations

International Nuclear Information System (INIS)

Zuchowski, R.

1981-01-01

Specimens made of four types of heat-resistant steels were used in the investigation. Various variants of loading process were applied, resulting in thermal fatigue, cyclic creep and isothermal fatigue. Stress or strain variation as well as intensity of acoustic emission were recorded during the tests as a function of time. Cyclic variations of strain or stress amplitude were found to occur one full period covering few to several cycles. Comparing the relative number of acoustic emission impulses with the variation of stress or strain leads to the conclusion that cyclic character of strain or stress variation results from cyclic character of damage cumulation process. This statement is confirmed by the results of material damage degree determination based on specific strain work measurements. Results of investigation testify to the equivalence of action (in terms of energy) of cyclically variable force field at constant temperature and of constant force field in the conditions of cyclic temperature variations. Damage mechanism can be different in each case, because it depends (for a given material) on loading process parameters and in particular - on temperature and stress value. (orig./HP)

Study of robust thin film PT-1000 temperature sensors for cryogenic process control applications

Science.gov (United States)

Ramalingam, R.; Boguhn, D.; Fillinger, H.; Schlachter, S. I.; Süßer, M.

2014-01-01

In some cryogenic process measurement applications, for example, in hydrogen technology and in high temperature superconductor based generators, there is a need of robust temperature sensors. These sensors should be able to measure the large temperature range of 20 - 500 K with reasonable resolution and accuracy. Thin film PT 1000 sensors could be a choice to cover this large temperature range. Twenty one sensors selected from the same production batch were tested for their temperature sensitivity which was then compared with different batch sensors. Furthermore, the sensor's stability was studied by subjecting the sensors to repeated temperature cycles of 78-525 K. Deviations in the resistance were investigated using ice point calibration and water triple point calibration methods. Also the study of directional oriented intense static magnetic field effects up to 8 Oersted (Oe) were conducted to understand its magneto resistance behaviour in the cryogenic temperature range from 77 K - 15 K. This paper reports all investigation results in detail.

Numerical modeling of hydration process and temperature evolution in early age concrete

NARCIS (Netherlands)

Caggiano, A.; Pepe, M.; Koenders, E.A.B.; Martinelli, E.; Etse, G.J.

2012-01-01

Heat production induced by the hydration reaction and the resulting temperature evolution in the early phases of setting and hardening processes are critical phenomena, often leading to premature cracking of concrete members. However, the interest for simulating such phenomena is also related to the

Establishing Relationship between Process Parameters and Temperature during High Speed End Milling of Soda Lime Glass

Science.gov (United States)

Nasima Bagum, Mst.; Konneh, Mohamed; Yeakub Ali, Mohammad

2018-01-01

In glass machining crack free surface is required in biomedical and optical industry. Ductile mode machining allows materials removal from brittle materials in a ductile manner rather than by brittle fracture. Although end milling is a versatile process, it has not been applied frequently for machining soda lime glass. Soda lime glass is a strain rate and temperature sensitive material; especially around glass transition temperature Tg, ductility increased and strength decreased. Hence, it is envisaged that the generated temperature by high-speed end milling (HSEM) could be brought close to the glass transition temperature, which promote ductile machining. In this research, the objective is to investigate the effect of high speed machining parameters on generated temperature. The cutting parameters were optimized to generate temperature around glass transition temperature of soda lime using response surface methodology (RSM). Result showed that the most influencing process parameter is feed rate followed by spindle speed and depth of cut to generate temperature. Confirmation test showed that combination of spindle speed 30,173 rpm, feed rate 13.2 mm/min and depth of cut 37.68 µm generate 635°C, hence ductile chip removal with machined surface Ra 0.358 µm was possible to achieve.

High temperature alloys for the primary circuit of a prototype nuclear process heat plant

International Nuclear Information System (INIS)

Ennis, P.J.; Schuster, H.

1979-01-01

As part of a comprehensive materials test programme for the High Temperature Reactor Project 'Prototype Plant for Nuclear Process Heat' (PNP), high temperature alloys are being investigated for primary circuit components operating at temperatures above 750 0 C. On the basis of important material parameters, in particular corrosion behaviour and mechanical properties in primary coolant helium, the potential of candidate alloys is discussed. By comparing specific PNP materials data with the requirements of PNP and those of conventional plant, the implications for the materials programme and component design are given. (orig.)

Steam generators secondary side chemical cleaning at Point Lepreau using the Siemen's high temperature process

International Nuclear Information System (INIS)

Verma, K.; MacNeil, C.; Odar, S.

1996-01-01

The secondary sides of all four steam generators at the Point Lepreau Nuclear Generating Stations were cleaned during the 1995 annual outage run-down using the Siemens high temperature chemical cleaning process. Traditionally all secondary side chemical cleaning exercises in CANDU as well as the other nuclear power stations in North America have been conducted using a process developed in conjunction with the Electric Power Research Institute (EPRI). The Siemens high temperature process was applied for the first time in North America at the Point Lepreau Nuclear Generating Station (PLGS). The paper discusses experiences related to the pre and post award chemical cleaning activities, chemical cleaning application, post cleaning inspection results and waste handling activities. (author)

Integration of solar thermal for improved energy efficiency in low-temperature-pinch industrial processes

International Nuclear Information System (INIS)

Atkins, Martin J.; Walmsley, Michael R.W.; Morrison, Andrew S.

2010-01-01

Solar thermal systems have the potential to provide renewable industrial process heat and are especially suited for low pinch temperature processes such as those in the food, beverage, and textile sectors. When correctly integrated within an industrial process, they can provide significant progress towards both increased energy efficiency and reduction in emissions. However, the integration of renewable solar energy into industrial processes presents a challenge for existing process integration techniques due to the non-continuous nature of the supply. A thorough pinch analysis study of the industrial process, taking in to account non-continuous operating rates, should be performed to evaluate the utility demand profile. Solar collector efficiency data under variable climatic conditions should also be collected for the specific site. A systematic method of combining this information leads to improved design and an optimal operating strategy. This approach has been applied to a New Zealand milk powder plant and benefits of several integration strategies, including mass integration, are investigated. The appropriate placement of the solar heat is analogous to the placement of a hot utility source and an energy penalty will be incurred when the solar thermal system provides heat below the pinch temperature.

Integration of solar thermal for improved energy efficiency in low-temperature-pinch industrial processes

Energy Technology Data Exchange (ETDEWEB)

Atkins, Martin J.; Walmsley, Michael R.W.; Morrison, Andrew S. [Energy Research Group, School of Science and Engineering, University of Waikato, Private Bag 3105, Hamilton 3240 (New Zealand)

2010-05-15

Solar thermal systems have the potential to provide renewable industrial process heat and are especially suited for low pinch temperature processes such as those in the food, beverage, and textile sectors. When correctly integrated within an industrial process, they can provide significant progress towards both increased energy efficiency and reduction in emissions. However, the integration of renewable solar energy into industrial processes presents a challenge for existing process integration techniques due to the non-continuous nature of the supply. A thorough pinch analysis study of the industrial process, taking in to account non-continuous operating rates, should be performed to evaluate the utility demand profile. Solar collector efficiency data under variable climatic conditions should also be collected for the specific site. A systematic method of combining this information leads to improved design and an optimal operating strategy. This approach has been applied to a New Zealand milk powder plant and benefits of several integration strategies, including mass integration, are investigated. The appropriate placement of the solar heat is analogous to the placement of a hot utility source and an energy penalty will be incurred when the solar thermal system provides heat below the pinch temperature. (author)

A process-level attribution of the annual cycle of surface temperature over the Maritime Continent

Science.gov (United States)

Li, Yana; Yang, Song; Deng, Yi; Hu, Xiaoming; Cai, Ming

2017-12-01

The annual cycle of the surface temperature over the Maritime Continent (MC) is characterized by two periods of rapid warming in March-April and September-October, respectively, and a period of rapid cooling in June-July. Based upon an analysis of energy balance within individual atmosphere-surface columns, the seasonal variations of surface temperature in the MC are partitioned into partial temperature changes associated with various radiative and non-radiative (dynamical) processes. The seasonal variations in direct solar forcing and surface latent heat flux show the largest positive contributions to the annual cycle of MC surface temperature while the changes in oceanic dynamics (including ocean heat content change) work against the temperature changes related to the annual cycle. The rapid warming in March-April is mainly a result of the changes in atmospheric quick processes and ocean-atmosphere coupling such as water vapor, surface latent heat flux, clouds, and atmospheric dynamics while the contributions from direct solar forcing and oceanic dynamics are negative. This feature is in contrast to that associated with the warming in September-October, which is driven mainly by the changes in solar forcing with a certain amount of contributions from water vapor and latent heat flux change. More contribution from atmospheric quick processes and ocean-atmosphere coupling in March-April coincides with the sudden northward movement of deep convection belt, while less contribution from these quick processes and coupling is accompanied with the convection belt slowly moving southward. The main contributors to the rapid cooling in June-July are the same as those to the rapid warming in March-April, and the cooling is also negatively contributed by direct solar forcing and oceanic dynamics. The changes in water vapor in all three periods contribute positively to the change in total temperature and they are associated with the change in the location of the center of

Automation Of An Analogue Temperature Control System For Chlorination Process Of Zircon Sand In A Bricket Form

International Nuclear Information System (INIS)

Triyono; Wasito, Bangun; Aryadi

2000-01-01

Automation of an analogue temperature control system for chlorination process of zircon sand in a bricket form has been carried out. Principally, automation of an analogue temperature control is a simple and a closed loop system model controller. The used controller system is an ON-OFF model thermocople probe as a sensor. The output system is in the form of ON-OFF relay which is connected to contactor relay, so that it is able to serve the chlorination furnace. The prepared automatic temperature control system for chlorination process of zircon sand has been continuously tested at temperatures between 800 to 1050 o C. This required heating times between 8 to 17 minutes

Sulfate reducing processes at extreme salinity and temperature. extending its application window

NARCIS (Netherlands)

Vallero, M.V.G.

2003-01-01

The characteristics of various sulfate-rich wastewaters, such as temperature, pH and salinity, are determined by the (industrial) process from which they originate, and can be far from the physiological optima of the sulfur cycle microorganisms. The main goal of the research described in this thesis

Recycling of hazardous solid waste material using high-temperature solar process heat

Energy Technology Data Exchange (ETDEWEB)

Schaffner, B.; Meier, A.; Wuillemin, D.; Hoffelner, W.; Steinfeld, A.

2003-03-01

A novel high-temperature solar chemical reactor is proposed for the thermal recycling of hazardous solid waste material using concentrated solar power. A 10 kW solar reactor prototype was designed and tested for the carbothermic reduction of electric arc furnace dusts (EAFD). The reactor was subjected to mean solar flux intensities of 2000 kW/m2 and operated in both batch and continuous mode within the temperature range 1120-1400 K. Extraction of up to 99% and 90% of the Zn originally contained in the EAFD was achieved in the residue for the batch and continuous solar experiments, respectively. The condensed off-gas products consisted mainly of Zn, Pb, and Cl. No ZnO was detected when the O{sub 2} concentration remained below 2 vol.-%. The use of concentrated solar energy as the source of process heat offers the possibility of converting hazardous solid waste material into valuable commodities for processes in closed and sustainable material cycles. (author)

The chemistry of tributyl phosphate at elevated temperatures in the Plutonium Finishing Plant Process Vessels

International Nuclear Information System (INIS)

Barney, G.S.; Cooper, T.D.

1994-01-01

Potentially violent chemical reactions of the tributyl phosphate solvent used by the Plutonium Finishing Plant at the Hanford Site were investigated. There is a small probability that a significant quantity of this solvent could be accidental transferred to heated process vessels and react there with nitric acid or plutonium nitrate also present in the solvent extraction process. The results of laboratory studies of the reactions show that exothermic oxidation of tributyl phosphate by either nitric acid or actinide nitrates is slow at temperatures expected in the heated vessels. Less than four percent of the tributyl phosphate will be oxidized in these vented vessels at temperatures between 125 degrees C and 250 degrees C because the oxidant will be lost from the vessels by vaporization or decomposition before the tributyl phosphate can be extensively oxidized. The net amounts of heat generated by oxidation with concentrated nitric acid and with thorium nitrate (a stand-in for plutonium nitrate) were determined to be about -150 and -220 joules per gram of tributyl phosphate initially present, respectively. This is not enough heat to cause violent reactions in the vessels. Pyrolysis of the tributyl phosphate occurred in these mixtures at temperatures of 110 degrees C to 270 degrees C and produced mainly 1-butene gas, water, and pyrophosphoric acid. Butene gas generation is slow at expected process vessel temperatures, but the rate is faster at higher temperatures. At 252 degrees C the rate of butene gas generated was 0.33 g butene/min/g of tributyl phosphate present. The measured heat absorbed by the pyrolysis reaction was 228 J/g of tributyl phosphate initially present (or 14.5 kcal/mole of tributyl phosphate). Release of flammable butene gas into process areas where it could ignite appears to be the most serious safety consideration for the Plutonium Finishing Plant

The chemistry of tributyl phosphate at elevated temperatures in the Plutonium Finishing Plant Process Vessels

Energy Technology Data Exchange (ETDEWEB)

Barney, G.S.; Cooper, T.D.

1994-06-01

Potentially violent chemical reactions of the tributyl phosphate solvent used by the Plutonium Finishing Plant at the Hanford Site were investigated. There is a small probability that a significant quantity of this solvent could be accidental transferred to heated process vessels and react there with nitric acid or plutonium nitrate also present in the solvent extraction process. The results of laboratory studies of the reactions show that exothermic oxidation of tributyl phosphate by either nitric acid or actinide nitrates is slow at temperatures expected in the heated vessels. Less than four percent of the tributyl phosphate will be oxidized in these vented vessels at temperatures between 125{degrees}C and 250{degrees}C because the oxidant will be lost from the vessels by vaporization or decomposition before the tributyl phosphate can be extensively oxidized. The net amounts of heat generated by oxidation with concentrated nitric acid and with thorium nitrate (a stand-in for plutonium nitrate) were determined to be about -150 and -220 joules per gram of tributyl phosphate initially present, respectively. This is not enough heat to cause violent reactions in the vessels. Pyrolysis of the tributyl phosphate occurred in these mixtures at temperatures of 110{degrees}C to 270{degrees}C and produced mainly 1-butene gas, water, and pyrophosphoric acid. Butene gas generation is slow at expected process vessel temperatures, but the rate is faster at higher temperatures. At 252{degrees}C the rate of butene gas generated was 0.33 g butene/min/g of tributyl phosphate present. The measured heat absorbed by the pyrolysis reaction was 228 J/g of tributyl phosphate initially present (or 14.5 kcal/mole of tributyl phosphate). Release of flammable butene gas into process areas where it could ignite appears to be the most serious safety consideration for the Plutonium Finishing Plant.

[Real time diagnostics of instantaneous temperature of combustion and explosion process by modern spectroscopy].

Science.gov (United States)

Zhou, Xue-tie; Wang, Jun-de; Li, Yan; Liu, Da-bing

2003-04-01

The combustion temperature is one of the important parameters to express flame combustion and explosion characteristics. It will effectively guide the design and manufacture of new model explosives, industrial explosive materials, and weapons. The recent developments and applications of real time diagnostics of instantaneous temperature of combustion and explosion processes by modern spectroscopic methods, such as atomic absorption-emission method, atomic emission two-line spectroscopy, atomic emission multiline spectroscopy, molecular rotation-vibration spectroscopy, coherent anti-stokes Raman scattering (CARS) and plane laser-induced fluorescence (PLIF), were reviewed in this paper. The maximum time resolution of atomic absorption-emission method is 25 microseconds. The time resolution of atomic emission two-line spectroscopy can reach 0.1 microsecond. These two methods can completely suit the need of real time and instantaneous temperature diagnostics of violent explosion and flame combustion. Other methods will also provide new effective research methods for the processes and characteristics of combustion, flame and explosion.

The synergy of corrosion and fretting wear process on Inconel 690 in the high temperature high pressure water environment

Science.gov (United States)

Wang, Zihao; Xu, Jian; Li, Jie; Xin, Long; Lu, Yonghao; Shoji, Tetsuo; Takeda, Yoichi; Otsuka, Yuichi; Mutoh, Yoshiharu

2018-04-01

The synergistic effect of corrosion and fretting process of the steam generator (SG) tube was investigated by using a self-designed high temperature test rig in this paper. The experiments were performed at 100°C , 200°C and 288°C , respectively. The fretting corrosion damage was studied by optical microscopy (OM), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), Raman spectroscopy and auger electron spectroscopy (AES). The results demonstrated that the corrosion process in high temperature high pressure (HTHP) water environment had a distinct interaction with the fretting process of Inconel 690. With the increment of temperature, the damage mechanism changed from a simple mechanical process to a mechanochemical process.

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%.

High-Pressure-High-Temperature Processing Reduces Maillard Reaction and Viscosity in Whey Protein-Sugar Solutions.

Science.gov (United States)

Avila Ruiz, Geraldine; Xi, Bingyan; Minor, Marcel; Sala, Guido; van Boekel, Martinus; Fogliano, Vincenzo; Stieger, Markus

2016-09-28

The aim of the study was to determine the influence of pressure in high-pressure-high-temperature (HPHT) processing on Maillard reactions and protein aggregation of whey protein-sugar solutions. Solutions of whey protein isolate containing either glucose or trehalose at pH 6, 7, and 9 were treated by HPHT processing or conventional high-temperature (HT) treatments. Browning was reduced, and early and advanced Maillard reactions were retarded under HPHT processing at all pH values compared to HT treatment. HPHT induced a larger pH drop than HT treatments, especially at pH 9, which was not associated with Maillard reactions. After HPHT processing at pH 7, protein aggregation and viscosity of whey protein isolate-glucose/trehalose solutions remained unchanged. It was concluded that HPHT processing can potentially improve the quality of protein-sugar-containing foods, for which browning and high viscosities are undesired, such as high-protein beverages.

Does magnesium compromise the high temperature process ability of novel biodegradable and bioresorbables PLLA/Mg composites?

International Nuclear Information System (INIS)

Cifuentes, S. C.; Benavemente, R.; Gonzalez-Carrasco, J. L.

2014-01-01

This paper addresses the influence of magnesium on melting behaviour and thermal stability of novel bioresorbable PLLA/Mg composites as a way to investigate their processability by conventional techniques, which likely will require a melt process at high temperature to mould the material by using a compression, extrusion or injection stage. For this purpose, and to avoid any high temperature step before analysis, films of PLLA loaded with magnesium particles of different sizes and volume fraction were prepared by solvent casting. DSC, modulated DSC and thermogravimetry analysis demonstrate that although thermal stability of PLLA is reduced, the temperature window for processing the PLLA/Mg composites by conventional thermoplastic routes is wide enough. Moreover, magnesium particles do not alter the crystallization behaviour of the polymer from the melt, which allows further annealing treatments to optimize the crystallinity in terms of the required combination of mechanical properties and degradation rate. (Author)

Does magnesium compromise the high temperature process ability of novel biodegradable and bioresorbables PLLA/Mg composites?

Energy Technology Data Exchange (ETDEWEB)

Cifuentes, S. C.; Benavemente, R.; Gonzalez-Carrasco, J. L.

2014-10-01

This paper addresses the influence of magnesium on melting behaviour and thermal stability of novel bioresorbable PLLA/Mg composites as a way to investigate their processability by conventional techniques, which likely will require a melt process at high temperature to mould the material by using a compression, extrusion or injection stage. For this purpose, and to avoid any high temperature step before analysis, films of PLLA loaded with magnesium particles of different sizes and volume fraction were prepared by solvent casting. DSC, modulated DSC and thermogravimetry analysis demonstrate that although thermal stability of PLLA is reduced, the temperature window for processing the PLLA/Mg composites by conventional thermoplastic routes is wide enough. Moreover, magnesium particles do not alter the crystallization behaviour of the polymer from the melt, which allows further annealing treatments to optimize the crystallinity in terms of the required combination of mechanical properties and degradation rate. (Author)

Thermal time constant: optimising the skin temperature predictive modelling in lower limb prostheses using Gaussian processes.

Science.gov (United States)

Mathur, Neha; Glesk, Ivan; Buis, Arjan

2016-06-01

Elevated skin temperature at the body/device interface of lower-limb prostheses is one of the major factors that affect tissue health. The heat dissipation in prosthetic sockets is greatly influenced by the thermal conductive properties of the hard socket and liner material employed. However, monitoring of the interface temperature at skin level in lower-limb prosthesis is notoriously complicated. This is due to the flexible nature of the interface liners used which requires consistent positioning of sensors during donning and doffing. Predicting the residual limb temperature by monitoring the temperature between socket and liner rather than skin and liner could be an important step in alleviating complaints on increased temperature and perspiration in prosthetic sockets. To predict the residual limb temperature, a machine learning algorithm - Gaussian processes is employed, which utilizes the thermal time constant values of commonly used socket and liner materials. This Letter highlights the relevance of thermal time constant of prosthetic materials in Gaussian processes technique which would be useful in addressing the challenge of non-invasively monitoring the residual limb skin temperature. With the introduction of thermal time constant, the model can be optimised and generalised for a given prosthetic setup, thereby making the predictions more reliable.

Antimony assisted low-temperature processing of CuIn1-xGaxSe2-ySy solar cells

International Nuclear Information System (INIS)

Yuan Min; Mitzi, David B.; Gunawan, Oki; Kellock, Andrew J.; Chey, S. Jay; Deline, Vaughn R.

2010-01-01

Application of the Sb-doping method to low-temperature (≤ 400 o C) processing of CuIn 1-x Ga x Se 2-y S y (CIGS) solar cells is explored, using a hydrazine-based approach to deposit the absorber films. Power conversion efficiencies of 10.5% and 8.4% have been achieved for CIGS devices (0.45 cm 2 device area) processed at 400 o C and 360 o C, respectively, with an Sb-incorporation level at 1.2 mol % (relative to the moles of CIGS). Significant Sb-induced grain size enhancement was confirmed for these low processing temperatures using cross-sectional scanning electron microscopy, and an average 2-3% absolute efficiency improvement was achieved in Sb-doped samples compared to their Sb-free sister samples. With Sb inclusion, the CIGS film grain growth temperature is lowered to well below 450 o C, a range compatible with flexible polymer substrate materials such as polyimide. This method opens up access to opportunities in low-temperature processing of CIGS solar cells, an area that is being actively pursued using both traditional vacuum-based as well as other solution-based deposition techniques.

Assessment of very high-temperature reactors in process application. Appendix I. Evaluation of the reactor system

International Nuclear Information System (INIS)

Jones, J.E. Jr.; Spiewak, I.

1976-12-01

In April 1974, the U.S. Atomic Energy Commission [now the Energy Research and Development Administration (ERDA)] authorized General Atomic Company, General Electric Company, and Westinghouse Electric Corp., Astronuclear Laboratory, to assess the available technology for producing heat using very high-temperature nuclear reactors. An evaulation of these studies and of the technical and economic potential of very high-temperature reactors (VHTR) is presented. The VHTR is a helium-cooled graphite-moderated reactor. The concepts and technology are evaluated for producing process stream temperatures of 649, 760, 871, 982, and 1093 0 C (1200, 1400, 1600, 1800, and 2000 0 F). There are a number of large industrial process heat applications that could utilize the VHTR

Patented Techniques for Acrylamide Mitigation in High-Temperature Processed Foods

DEFF Research Database (Denmark)

Mariotti, Salome; Pedreschi, Franco; Antonio Carrasco, José

2011-01-01

Heating foods has many advantages since it adds taste, color, texture and minimizes harmful germs, among others. Flavor and aroma compounds are produced via the Maillard reaction, where various hazardous com-pounds may form as well, such as acrylamide. Maillard reaction is believed to be the main...... for acrylamide reduction in foods processed at high temperatures are mentioned and briefly analyzed in order to develop new mitigation techniques for acrylamide in different food matrixes.......Heating foods has many advantages since it adds taste, color, texture and minimizes harmful germs, among others. Flavor and aroma compounds are produced via the Maillard reaction, where various hazardous com-pounds may form as well, such as acrylamide. Maillard reaction is believed to be the main...... route for acrylamide for-mation between reducing sugars (glucose and fructose), sucrose, and the amino acid asparagine, and, consequently, a variety of technologies have been developed to reduce acrylamide concentration in thermally processed foods based ei-ther on: (i) Changing process parameters (e...

Influence of thermally activated processes on the deformation behavior during low temperature ECAP

Science.gov (United States)

Fritsch, S.; Scholze, M.; F-X Wagner, M.

2016-03-01

High strength aluminum alloys are generally hard to deform. Therefore, the application of conventional severe plastic deformation methods to generate ultrafine-grained microstructures and to further increase strength is considerably limited. In this study, we consider low temperature deformation in a custom-built, cooled equal channel angular pressing (ECAP) tool (internal angle 90°) as an alternative approach to severely plastically deform a 7075 aluminum alloy. To document the maximum improvement of mechanical properties, these alloys are initially deformed from a solid solution heat-treated condition. We characterize the mechanical behavior and the microstructure of the coarse grained initial material at different low temperatures, and we analyze how a tendency for the PLC effect and the strain-hardening rate affect the formability during subsequent severe plastic deformation at low temperatures. We then discuss how the deformation temperature and velocity influence the occurrence of PLC effects and the homogeneity of the deformed ECAP billets. Besides the mechanical properties and these microstructural changes, we discuss technologically relevant processing parameters (such as pressing forces) and practical limitations, as well as changes in fracture behavior of the low temperature deformed materials as a function of deformation temperature.

Reduction of cyanogenic glycosides by extrusion - influence of temperature and moisture content of the processed material

Directory of Open Access Journals (Sweden)

Čolović Dušica S.

2015-01-01

Full Text Available Тhe paper presents results of the investigation of the influence of extrusion temperature and moisture content of treated material on the reduction of cyanogenic glycosides (CGs in linseed-based co-extrudate. CGs are the major limitation of the effective usage of linseed in animal nutrition. Hence, some technological process must be applied for detoxification of linseed before its application as a nutrient. Extrusion process has demonstrated several advantages in reducing the present CGs, since it combines the influences of heating, shearing, high pressure, mixing, etc. According to obtained results, the increase in both temperature and moisture content of the starting mixture decreased the content of CGs in the processed material. HCN content, as a measurement of GCs presence, ranged from 25.42 mg/kg, recorded at the moisture content of 11.5%, to 126 mg/kg, detected at the lowest moisture content of 7%. It seems that moisture content and temperature had the impact on HCN content of equal importance. However, the influence of extrusion parameters other than temperature and moisture content could not be neglected. Therefore, the impact of individual factors has to be tested together. [Projekat Ministarstva nauke Republike Srbije, br. III 46012

EUROPAIRS: The European project on coupling of High Temperature Reactors with industrial processes

International Nuclear Information System (INIS)

Angulo, C.; Bogusch, E.; Bredimas, A.; Delannay, N.; Viala, C.; Ruer, J.; Muguerra, Ph.; Sibaud, E.; Chauvet, V.; Hittner, D.; Fütterer, M.A.; Groot, S. de; Lensa, W. von; Verfondern, K.; Moron, R.; Baudrand, O.; Griffay, G.; Baaten, A.; Segurado-Gimenez, J.

2012-01-01

Developers of High Temperature Reactors (HTR) worldwide acknowledge that the main asset for market breakthrough is its unique ability to address growing needs for industrial cogeneration of heat and power (CHP) owing to its high operating temperature and flexibility, adapted power level, modularity and robust safety features. A strong alliance between nuclear and process heat user industries is a necessity for developing such a nuclear system for the conventional process heat market, just as the electro-nuclear development required a close partnership with utilities. Initiating such an alliance is one of the objectives of the EUROPAIRS project ( (www.europairs.eu)) presently on-going in the frame of the Euratom 7th Framework Programme (FP7). Although small and of short duration (21 months), EUROPAIRS is of strategic importance: it generates the boundary conditions for rapid demonstration of collocating HTR with industrial processes as proposed by the European High Temperature Reactor Technology Network (HTR-TN). This paper presents the main goals, the organization and the working approach of EUROPAIRS. It also presents the status of the viability assessment studies for coupling HTR with industrial end-user systems as one of the main pillars of the project. The main goal of the viability assessment is to identify developments required to remove the last technological and licensing barriers for a viable coupling scheme. The study is expected to result in guidelines for directing the choice of an industrial scale prototype.

EUROPAIRS: The European project on coupling of High Temperature Reactors with industrial processes

Energy Technology Data Exchange (ETDEWEB)

Angulo, C., E-mail: carmen.angulo@gdfsuez.com [Tractebel Engineering S.A. (GDF SUEZ), Avenue Ariane 7, 1200 Brussels (Belgium); Bogusch, E. [AREVA NP GmbH, Paul-Gossen-Strasse 100, 91052 Erlangen (Germany); Bredimas, A. [LGI Consulting, 37 rue de la Grange aux Belles, 75010 Paris (France); Delannay, N. [Tractebel Engineering S.A. (GDF SUEZ), Avenue Ariane 7, 1200 Brussels (Belgium); Viala, C. [AREVA NP SAS, 10 rue Juliette Recamier, 69456 Lyon Cedex 06 (France); Ruer, J.; Muguerra, Ph.; Sibaud, E. [SAIPEM S.A., 1/7 Avenue San Fernando, 78884 Saint Quentin en Yvelines Cedex (France); Chauvet, V. [LGI Consulting, 37 rue de la Grange aux Belles, 75010 Paris (France); Hittner, D. [AREVA NP Inc., 3315 Old Forest Road, Lynchburg, VA 24501 (United States); Fuetterer, M.A. [European Commission, Joint Research Centre, 1755ZG Petten (Netherlands); Groot, S. de [Nuclear Research and Consultancy Group, 1755ZG Petten (Netherlands); Lensa, W. von; Verfondern, K. [Forschungszentrum Juelich GmbH, Leo-Brandt-Strasse,52425 Juelich (Germany); Moron, R. [Solvay SA, rue du Prince Albert 33, 1050 Brussels (Belgium); Baudrand, O. [Institut de Radioprotection et de Surete Nucleaire (IRSN), BP 17, 92262 Fontenay-aux-Roses cedex (France); Griffay, G. [Arcelor Mittal Maizieres Research SA, rue Luigi Cherubini 1A5, 39200 Saint Denis (France); Baaten, A. [USG/Baaten Energy Consulting, Burgermeester-Ceulen-Straat 78, 6212CT Maastricht (Netherlands); Segurado-Gimenez, J. [Tractebel Engineering S.A. (GDF SUEZ), Avenue Ariane 7, 1200 Brussels (Belgium)

2012-10-15

Developers of High Temperature Reactors (HTR) worldwide acknowledge that the main asset for market breakthrough is its unique ability to address growing needs for industrial cogeneration of heat and power (CHP) owing to its high operating temperature and flexibility, adapted power level, modularity and robust safety features. A strong alliance between nuclear and process heat user industries is a necessity for developing such a nuclear system for the conventional process heat market, just as the electro-nuclear development required a close partnership with utilities. Initiating such an alliance is one of the objectives of the EUROPAIRS project ( (www.europairs.eu)) presently on-going in the frame of the Euratom 7th Framework Programme (FP7). Although small and of short duration (21 months), EUROPAIRS is of strategic importance: it generates the boundary conditions for rapid demonstration of collocating HTR with industrial processes as proposed by the European High Temperature Reactor Technology Network (HTR-TN). This paper presents the main goals, the organization and the working approach of EUROPAIRS. It also presents the status of the viability assessment studies for coupling HTR with industrial end-user systems as one of the main pillars of the project. The main goal of the viability assessment is to identify developments required to remove the last technological and licensing barriers for a viable coupling scheme. The study is expected to result in guidelines for directing the choice of an industrial scale prototype.

Effect of the Preheating Temperature on Process Time in Friction Stir Welding of Al 6061-T6

DEFF Research Database (Denmark)

Jabbari, Masoud

2013-01-01

This paper presents the results obtained and the deductions made from an analytical modeling involving friction stir welding of Al 6061-T6. A new database was developed to simulate the contact temperature between the tool and the workpiece. A second-order equation is proposed for simulating...... the temperature in the contact boundary and the thermal history during the plunge phase. The effect of the preheating temperature on the process time was investigated with the proposed model. The results show that an increase of the preheating time leads to a decrease in the process time up to the plunge...

Low Temperature Processed Complementary Metal Oxide Semiconductor (CMOS) Device by Oxidation Effect from Capping Layer

KAUST Repository

Wang, Zhenwei

2015-04-20

In this report, both p- and n-type tin oxide thin-film transistors (TFTs) were simultaneously achieved using single-step deposition of the tin oxide channel layer. The tuning of charge carrier polarity in the tin oxide channel is achieved by selectively depositing a copper oxide capping layer on top of tin oxide, which serves as an oxygen source, providing additional oxygen to form an n-type tin dioxide phase. The oxidation process can be realized by annealing at temperature as low as 190°C in air, which is significantly lower than the temperature generally required to form tin dioxide. Based on this approach, CMOS inverters based entirely on tin oxide TFTs were fabricated. Our method provides a solution to lower the process temperature for tin dioxide phase, which facilitates the application of this transparent oxide semiconductor in emerging electronic devices field.

The effect of temperature and gas flow rate on the carbochlorination process of ZrO2

International Nuclear Information System (INIS)

Saberyan, K.; Raygan, Sh.; Movahhedian, A.; Hosseini Semnani, S. A.

2007-01-01

Carbochlorination of ZrO 2 is the main part of zirconium production process. In this research the effect of temperature and total gas flow rate on carbochlorination of ZrO 2 in the presence of carbon black was investigated. The partial pressure of Cl 2 in this study was kept at 0.3 atmosphere. The results showed that ZrO 2 conversion is strongly affected by the temperature. It is also shown that at 1223 K, the process is affected by the gas flow rate. The activation energy of the process was 60 kCal/mol and the chemical reaction on the oxide surface was the dominant controller of the reaction

Highly Efficient Reproducible Perovskite Solar Cells Prepared by Low-Temperature Processing

Directory of Open Access Journals (Sweden)

Hao Hu

2016-04-01

Full Text Available In this work, we describe the role of the different layers in perovskite solar cells to achieve reproducible, ~16% efficient perovskite solar cells. We used a planar device architecture with PEDOT:PSS on the bottom, followed by the perovskite layer and an evaporated C60 layer before deposition of the top electrode. No high temperature annealing step is needed, which also allows processing on flexible plastic substrates. Only the optimization of all of these layers leads to highly efficient and reproducible results. In this work, we describe the effects of different processing conditions, especially the influence of the C60 top layer on the device performance.

Optimizing solid oxide fuel cell cathode processing route for intermediate temperature operation

DEFF Research Database (Denmark)

Ortiz-Vitoriano, N.; Bernuy-Lopez, Carlos; Ruiz de Larramendi, I.

2013-01-01

-priced raw material and cost-effective production techniques.In this work the perovskite-type La0.6Ca0.4Fe0.8Ni0.2O3 (LCFN) oxide has been used in order to optimize intermediate temperature SOFC cathode processing route. The advantages this material presents arise from the low temperature powder calcination......For Solid Oxide Fuel Cells (SOFCs) to become an economically attractive energy conversion technology suitable materials which allow operation at lower temperatures, while retaining cell performance, must be developed. At the same time, the cell components must be inexpensive - requiring both low...... (∼600°C) and electrode sintering (∼800°C) of LCFN electrodes, making them a cheaper alternative to conventional SOFC cathodes. An electrode polarization resistance as low as 0.10Ωcm2 at 800°C is reported, as determined by impedance spectroscopy studies of symmetrical cells sintered at a range...

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)

Use of the inverse temperature profile in microwave processing of advanced ceramics

International Nuclear Information System (INIS)

Binner, J.G.P.; Al-Dawery, I.A.; Aneziris, C.; Cross, T.E.

1992-01-01

Attempts are being made to exploit the inverse temperature profile which can be developed with microwave heating with respect to the processing of certain advanced ceramics. This paper discusses the results obtained to date during the microwave sintering of YBCO high-T c superconductors and the microwave reaction bonding of silicon nitride

Long-term sea surface temperature baselines - time series, spatial covariation and implications for biological processes

DEFF Research Database (Denmark)

MacKenzie, Brian; Schiedek, D.

2007-01-01

to 2 years. These differences suggest that spatial variations in physical oceanographic phenomena and sampling heterogeneities associated with opportunistic sampling could affect perceptions of biological responses to temperature fluctuations. The documentation that the coastally measured temperatures...... questions at large spatial scales, such as the response of species distributions and phenologies to climate change. In this study we investigate the spatial synchrony of long-term sea surface temperatures in the North Sea-Baltic Sea region as measured daily at four coastal sites (Marsdiep, Netherlands...... at coastal sites co-varied strongly with each other and with opportunistically measured offshore temperatures despite separation distances between measuring locations of 20-1200 km. This covariance is probably due to the influence of large-scale atmospheric processes on regional temperatures...

Modeling the high-temperature gas-cooled reactor process heat plant: a nuclear to chemical conversion process

International Nuclear Information System (INIS)

Pfremmer, R.D.; Openshaw, F.L.

1982-05-01

The high-temperature heat available from the High-Temperature Gas-Cooled Reactor (HTGR) makes it suitable for many process applications. One of these applications is a large-scale energy production plant where nuclear energy is converted into chemical energy and stored for industrial or utility applications. This concept combines presently available nuclear HTGR technology and energy conversion chemical technology. The design of this complex plant involves questions of interacting plant dynamics and overall plant control. This paper discusses how these questions were answered with the aid of a hybrid computer model that was developed within the time-frame of the conceptual design studies. A brief discussion is given of the generally good operability shown for the plant and of the specific potential problems and their anticipated solution. The paper stresses the advantages of providing this information in the earliest conceptual phases of the design

Effect of process parameters on temperature distribution in twin-electrode TIG coupling arc

Science.gov (United States)

Zhang, Guangjun; Xiong, Jun; Gao, Hongming; Wu, Lin

2012-10-01

The twin-electrode TIG coupling arc is a new type of welding heat source, which is generated in a single welding torch that has two tungsten electrodes insulated from each other. This paper aims at determining the distribution of temperature for the coupling arc using the Fowler-Milne method under the assumption of local thermodynamic equilibrium. The influences of welding current, arc length, and distance between both electrode tips on temperature distribution of the coupling arc were analyzed. Based on the results, a better understanding of the twin-electrode TIG welding process was obtained.

Modeling Coupled THM Processes and Brine Migration in Salt at High Temperatures

Energy Technology Data Exchange (ETDEWEB)

Rutqvist, Jonny [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Blanco-Martin, Laura [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Molins, Sergi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Trebotich, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Birkholzer, Jens [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2015-09-01

In this report, we present FY2015 progress by Lawrence Berkeley National Laboratory (LBNL) related to modeling of coupled thermal-hydrological-mechanical-chemical (THMC) processes in salt and their effect on brine migration at high temperatures. This is a combined milestone report related to milestone Salt R&D Milestone “Modeling Coupled THM Processes and Brine Migration in Salt at High Temperatures” (M3FT-15LB0818012) and the Salt Field Testing Milestone (M3FT-15LB0819022) to support the overall objectives of the salt field test planning.

Advances in processing of NiAl intermetallic alloys and composites for high temperature aerospace applications

Science.gov (United States)

Bochenek, Kamil; Basista, Michal

2015-11-01

Over the last few decades intermetallic compounds such as NiAl have been considered as potential high temperature structural materials for aerospace industry. A large number of investigations have been reported describing complex fabrication routes, introducing various reinforcing/alloying elements along with theoretical analyses. These research works were mainly focused on the overcoming of main disadvantage of nickel aluminides that still restricts their application range, i.e. brittleness at room temperature. In this paper we present an overview of research on NiAl processing and indicate methods that are promising in solving the low fracture toughness issue at room temperature. Other material properties relevant for high temperature applications are also addressed. The analysis is primarily done from the perspective of NiAl application in aero engines in temperature regimes from room up to the operating temperature (over 1150 °C) of turbine blades.

Time and temperature reduction of the sealing process of porous aluminium oxide films with organic additives

International Nuclear Information System (INIS)

Bautista, A.; Lopez, V.; Otero, E.; Lizarbe, R.; Gonzalez, J.A.

1998-01-01

Different sealing processes of anode coating in aluminium oxide have been industrially used for more than 30 years. In two of the preceding decades a great effort was realized to reduce costs in the traditional hydrothermal sealing in deionized boiling water (SHT), a very expensive process due to its endurance and high temperature on which it develops. New sealing procedures are proposed, on which by means of the use of organic additives, the time or the temperature of the SHT is essentially reduced. (Author) 10 refs

Investigation of optimal manufacturing process for freeze-dried formulations: Observation of frozen solutions by low temperature X-ray diffraction measurements

International Nuclear Information System (INIS)

Egawa, Hiroaki; Yonemochi, Etsuo; Terada, Katsuhide

2005-01-01

Freeze-drying is used for the production of sterile injections in the pharmaceutical industry. However, most pharmaceutical compounds are obtained as less stable amorphous form. Freeze crystallization by annealing is an effective method for pharmaceutical compounds that fail to crystallize in the freeze-drying process. Crystallization occurs in the frozen solution during the thermal treatment. In order to establish suitable annealing conditions efficiently, it is important to observe the crystallization process directly in the frozen solution. Recently, low temperature X-ray diffraction has been used to observe frozen solutions. In order to investigate the crystallization process kinetically, the temperature of the low temperature X-ray diffraction instrument must be accurately controlled. We calibrated the temperature of X-ray diffraction instrument by measuring eutectic temperatures of solutions for a series of compounds. Each eutectic crystal was observed in frozen solution with ice crystal below the eutectic temperature. Eutectic temperatures were detected by the decrease in diffraction intensity associated with heating from below the eutectic temperature. Good correlation was obtained between values in the literature and experimental values

QUALITY OF MINIMALLY PROCESSED YAM (Dioscorea sp. STORED AT TWO DIFFERENT TEMPERATURES

Directory of Open Access Journals (Sweden)

ADRIANO DO NASCIMENTO SIMÕES

2016-01-01

Full Text Available This work studied the physical, chemical and bio chemical alterations in minimally processed yam stored at two different temperatures, as well a s the incidence of bacteria of the genus Pseudomonas . The experimental design was completely randomised in a 2x8 factorial design, with two storage temperature s (5 and 10°C and eight storage times (0, 2, 4, 6, 8, 1 0, 12 and 14 days. Experiments were in triplicate. Yam was selected, peeled and cut into slices of approximate ly 3 cm thickness. The slices were rinsed with wate r, sanitised and then drained in kitchen strainers. Ap proximately 300 g of the processed product were pac ked in nylon multilayers 15 μ m thick, 15 cm wide and 20 cm long. The packs were sealed, weighed and kept at 5 and 10 ± 2°C for 14 days. Fresh weight loss, baking tim e, enzymatic activity of polyphenol oxidases, perox idases and catalases, total soluble phenol content, and an tioxidant capacity were evaluated, as well as visua l analysis and incidence of Pseudomonas sp. Means of temperatures were compared by Tukey ́s test at 5% significance. Yam storage at 5°C reduced weight loss and kept vis ual quality for longer; it also reduced cooking tim e and the activity of the enzymes polyphenol oxidase and pero xidase. In contrast, it promoted higher content of total soluble phenols, as well as a higher catalase activ ity and antioxidant capacity. During the storage ti me, there was no incidence of Pseudomonas sp. Minimally processed yam stored at 10°C may be sold for up to six days, and yam stored at 5ºC for up to 14 days.

Brazing process for beryllium pieces at a temperature lower than 800 deg

International Nuclear Information System (INIS)

Cerutti, R.; Flegeau, G.; Haas, C.

1992-01-01

This patent describes a brazing process of a beryllium plate with monel rod at a temperature lower than 1073 K under high vacuum. The brazing alloy is composed (% in weight) of silver (58 to 65%), copper (26 to 29%), indium (9 to 13%) and titanium (0 to 2%). (A.B.). 4 refs., 1 fig

Dislocation polymorphism transformation of 6061-T651 aluminum alloy processed by laser shock processing: Effect of tempering at the elevated temperatures

International Nuclear Information System (INIS)

Ren, X.D.; Ruan, L.; Yuan, S.Q.; Ren, N.F.; Zheng, L.M.; Zhan, Q.B.; Zhou, J.Z.; Yang, H.M.; Wang, Y.; Dai, F.Z.

2013-01-01

The effects of tempering on surface topography and dislocation configuration of 6061-T651 aluminum alloy by laser shock processing (LSP) were investigated at the elevated temperatures. Surface topography and surface roughness were tested by a Surfcom 130A-Monochrome surface rough-meter. Morphologies of precipitated phases were monitored by scanning electron microscopy (SEM), and the dislocation configurations of samples after LSP were characterized by transmission electron microscope (TEM). The results showed that LSP had a beneficial effect on micro-hardness at elevated temperature. There was a little change of the surface roughness as subjected to LSP. The main strengthening mechanism of micro-hardness was dislocation strengthening and fine grain strengthening, and precipitated phase strengthening was the main strengthening mechanism at elevated temperature. “Dislocation polymorphism transformation” (DPT) effect was affirmed at elevated temperature, and the elevated temperature was principal element for inducing the DPT effect of 6061-T651 aluminum alloy by LSP

Software tools for data modelling and processing of human body temperature circadian dynamics.

Science.gov (United States)

Petrova, Elena S; Afanasova, Anastasia I

2015-01-01

This paper is presenting a software development for simulating and processing thermometry data. The motivation of this research is the miniaturization of actuators attached to human body which allow frequent temperature measurements and improve the medical diagnosis procedures related to circadian dynamics.

Nutritional Potential and Functionality of Whey Powder Influenced by Different Processing Temperature and Storage

OpenAIRE

Zarmina Gillani; Nuzhat Huma; Aysha Sameen; Mulazim Hussain Bukhari

2017-01-01

Whey is an excellent food ingredient owing to its high nutritive value and its functional properties. However, composition of whey varies depending on composition of milk, processing conditions, processing method, and its whey protein content. The aim of this study was to prepare a whey powder from raw whey and to determine the influence of different processing temperatures (160 and 180 °C) on the physicochemical, functional properties during storage of 180 days and on whey protein denaturati...

EFFECT OF TEMPERATURE AND pH OF MODIFICATION PROCESS ON THE PHYSICAL-MECHANICAL PROPERTIES OF MODIFIED CASSAVA STARCH

Directory of Open Access Journals (Sweden)

Yudi Wicaksono

2016-11-01

Full Text Available The use of cassava starch for excipient in the manufacturing of the tablet has some problems, especially on physical-mechanical properties. The purpose of this study was to determine the effect of the differentness of temperature and pH in the process of modification on the physical-mechanical properties of modified cassava starch. Modifications were performed by suspending cassava starch into a solution of 3 % (w/v PVP K30. The effect of the difference of temperature was observed at temperatures of 25; 45 and 65 0C, while the effect of the difference of pH was observed at pH of 4.0; 7.0 and 12.0. The results showed that the temperature and pH did not affect the physical-mechanical properties of the modified cassava starch. Modification of cassava starch at pH and temperature of 7.0 and 45 0C was produced modified cassava starch with the most excellent solubility, while the best swelling power were formed by the modification process at pH and temperature of 7.0 and 25 0C. Overall, the most excellent compression properties of modified cassava starch resulted from the modification process at pH 12.

Investigation of heat flux processes governing the increase of groundwater temperatures beneath cities

Science.gov (United States)

Bayer, P.; Menberg, K.; Zhu, K.; Blum, P.

2012-12-01

In the subsurface of many cities there are widespread and persistent thermal anomalies. These so-called subsurface urban heat islands (UHIs), which also stimulate warming of urban aquifers, are triggered by various processes. Possible heat sources are basements of buildings, leakage of sewage systems, buried district heating networks, re-injection of cooling water and solar irradiation on paved surfaces. In the current study, the reported groundwater temperatures in several Central European cities, such as Berlin, Cologne (Germany) and Zurich (Switzerland) are compared. Available data sets are supplemented by temperature measurements and depth profiles in observation wells. Trend analyses are conducted with time series of groundwater temperatures, and three-dimensional groundwater temperature maps are provided. In all investigated cities, pronounced positive temperature anomalies are present. The distribution of groundwater temperatures appears to be spatially and temporally highly variable. Apparently, the increased heat input into the urban subsurface is controlled by very local and site-specific parameters. In the long-run, the combination of various heat sources results in an extensive temperature increase. In many cases, the maximum temperature elevation is found close to the city center. Regional groundwater temperature differences between the city center and the rural background are up to 5 °C, with local hot spots of even more pronounced anomalies. Particular heat sources, like cooling water injections or case-specific underground constructions, can cause local temperatures > 20 °C in the subsurface. Examination of the long-term variations in isotherm maps shows that temperatures have increased by about 1 °C in the city, as well as in the rural background areas over the last decades. This increase could be reproduced with trend analysis of temperature data gathered from several groundwater wells. Comparison between groundwater and air temperatures in the

Numerical simulation of the laser welding process for the prediction of temperature distribution on welded aluminium aircraft components

Science.gov (United States)

Tsirkas, S. A.

2018-03-01

The present investigation is focused to the modelling of the temperature field in aluminium aircraft components welded by a CO2 laser. A three-dimensional finite element model has been developed to simulate the laser welding process and predict the temperature distribution in T-joint laser welded plates with fillet material. The simulation of the laser beam welding process was performed using a nonlinear heat transfer analysis, based on a keyhole formation model analysis. The model employs the technique of element ;birth and death; in order to simulate the weld fillet. Various phenomena associated with welding like temperature dependent material properties and heat losses through convection and radiation were accounted for in the model. The materials considered were 6056-T78 and 6013-T4 aluminium alloys, commonly used for aircraft components. The temperature distribution during laser welding process has been calculated numerically and validated by experimental measurements on different locations of the welded structure. The numerical results are in good agreement with the experimental measurements.

Process for improving the low temperature ductility of tungsten-base composites

International Nuclear Information System (INIS)

Zukas, E.G.

1975-05-01

At temperatures below about 100 0 C, liquid-phase-sintered tungsten-base composites fail in a brittle manner because of the formation of cleavage cracks in the tungsten spheroids. Improving the ductility, then, would require some alloying addition or treatment which would improve the ductility of these spheroids, or some method of changing the stress distribution, such as putting the surface in compression, which would reduce stress concentrations and thereby require a higher load to initiate fracture. The ductilizing process used here consists of coating the composite with a ductile metal followed by heat treating at a high enough temperature to insure sufficient diffusion so that the coat and base become integral. The ductile coat is now the 'piece' surface, and the initiation of cleavage cracks requires much greater stresses. Coats of copper, nickel, gold, and cobalt have been used successfully. A possible added advantage is that the surface properties can now be controlled if certain reflective properties or corrosion resistance are needed. Also soldering or low temperature brazing operations are feasible, allowing the construction or assembly of intricate shapes which could not be accomplished previously. (U.S.)

Critical process temperatures for resistive InGaAsP/InP heterostructures heavily implanted by Fe or Ga ions

Energy Technology Data Exchange (ETDEWEB)

Fekecs, André [Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, Sherbrooke, QC J1K 0A5 (Canada); Regroupement Québécois sur les Matériaux de Pointe, QC (Canada); Chicoine, Martin [Département de Physique, Université de Montréal, Montréal, QC H3C 3J7 (Canada); Regroupement Québécois sur les Matériaux de Pointe, QC (Canada); Ilahi, Bouraoui [Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, Sherbrooke, QC J1K 0A5 (Canada); SpringThorpe, Anthony J. [Canadian Photonics Fabrication Centre, National Research Council, Ottawa, ON K1A 0R6 (Canada); Schiettekatte, François [Département de Physique, Université de Montréal, Montréal, QC H3C 3J7 (Canada); Regroupement Québécois sur les Matériaux de Pointe, QC (Canada); Morris, Denis [Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, Sherbrooke, QC J1K 0A5 (Canada); Regroupement Québécois sur les Matériaux de Pointe, QC (Canada); and others

2015-09-15

Highlights: • InGaAsP/InP alloys were processed by MeV ion implantation and rapid thermal annealing. • X-ray diffraction and Hall measurement results are compared for several process conditions. • Amorphous layers formed at low implantation temperature. • Dynamic annealing prevented amorphization at implantation above room temperature. • After annealing near 500 °C, sheet resistivities of 10{sup 7} Ω/sq were obtained with low temperature Fe implantation. - Abstract: We report on critical ion implantation and rapid thermal annealing (RTA) process temperatures that produce resistive Fe- or Ga-implanted InGaAsP/InP heterostructures. Two InGaAsP/InP heterostructure compositions, with band gap wavelengths of 1.3 μm and 1.57 μm, were processed by ion implantation sequences done at multiple MeV energies and high fluence (10{sup 15} cm{sup −2}). The optimization of the fabrication process was closely related to the implantation temperature which influences the type of implant-induced defect structures. With hot implantation temperatures, at 373 K and 473 K, X-ray diffraction (XRD) revealed that dynamic defect annealing was strong and prevented the amorphization of the InGaAsP layers. These hot-implanted layers were less resistive and RTA could not optimize them systematically in favor of high resistivity. With cold implantation temperatures, at 83 K and even at 300 K, dynamic annealing was minimized. Damage clusters could form and accumulate to produce resistive amorphous-like structures. After recrystallization by RTA, polycrystalline signatures were found on every low-temperature Fe- and Ga-implanted structures. For both ion species, electrical parameters evolved similarly against annealing temperatures, and resistive structures were produced near 500 °C. However, better isolation was obtained with Fe implantation. Differences in sheet resistivities between the two alloy compositions were less than band gap-related effects. These observations, related

Modeling Coupled THMC Processes and Brine Migration in Salt at High Temperatures

Energy Technology Data Exchange (ETDEWEB)

Rutqvist, Jonny; Blanco Martin, Laura; Mukhopadhyay, Sumit; Houseworth, Jim; Birkholzer, Jens

2014-08-14

In this report, we present FY2014 progress by Lawrence Berkeley National Laboratory (LBNL) related to modeling of coupled thermal-hydrological-mechanical-chemical (THMC) processes in salt and their effect on brine migration at high temperatures. LBNL’s work on the modeling of coupled THMC processes in salt was initiated in FY2012, focusing on exploring and demonstrating the capabilities of an existing LBNL modeling tool (TOUGH-FLAC) for simulating temperature-driven coupled flow and geomechanical processes in salt. This work includes development related to, and implementation of, essential capabilities, as well as testing the model against relevant information and published experimental data related to the fate and transport of water. we provide more details on the FY2014 work, first presenting updated tools and improvements made to the TOUGH-FLAC simulator, and the use of this updated tool in a new model simulation of long-term THM behavior within a generic repository in a salt formation. This is followed by the description of current benchmarking and validations efforts, including the TSDE experiment. We then present the current status in the development of constitutive relationships and the dual-continuum model for brine migration. We conclude with an outlook for FY2015, which will be much focused on model validation against field experiments and on the use of the model for the design studies related to a proposed heater experiment.

Novel low-temperature processing of low noise SDDs with on-detector electronics

International Nuclear Information System (INIS)

Sonsky, J.; Koornneef, R.; Huizenga, J.; Hollander, R.W.; Nanver, L.K.; Scholtes, T.; Roozeboom, F.; Eijk, C.W.E. van

2004-01-01

We have developed a fabrication process (SMART700 deg. process) for monolithic integration of p-channel JFETs and silicon detectors. Processing steps of the SMART700 deg. do not exceed 700 deg. C. The integrated p-JFET has a minimum gate length of 1 μm. A relatively large width can be chosen to achieve a reasonable transconductance, while the JFET capacitance still matches the small capacitance of a detector. The feedback capacitor was also realized on-chip as a double-metal capacitor. In this paper we describe DC and noise characteristics of a silicon drift detector (SDD) with a p-JFET (W/L=100/1) and a feedback capacitor integrated in the read-out anode (smart-SDD). The device has a transconductance of 1-3 mS, a top gate capacitance of ∼140 fF and a low leakage current ( 2 at room temperature). The smart-SDD with an active area of 3.8 mm 2 has reached an energy resolution of ∼50 rms electrons at a temperature of 213 K. This relatively poor energy resolution is due to generation-recombination noise caused by defects produced by a deep n-implantation. Rapid thermal annealing (RTA) and excimer laser annealing (ELA) techniques are experimented to remove the implantation damage. The noise of p-JFETs annealed with RTA and ELA is also presented

Characterization of microcrystalline I-layer for solar cells prepared in low temperature - plastic compatible process

KAUST Repository

Sliz, Rafal

2012-06-01

Microcrystalline silicon (mc-Si) lms deposited using a Plasma Enhanced Chemical Vapour Deposition (PECVD) process constitute an important material for manufacturing low-cost, large-area thin-lm devices, such as solar cells or thin-lm transistors. Although the deposition of electronic-grade mc-Si using the PECVD process is now well established, the high substrate temperature required (~400°C) does not lend itself to electronic devices with exible form factors fabricated on low-cost plastic substrates. In this study, we rst investigated an intrinsic mc-Si layer deposited at plastic-compatible substrate temperatures (~150°C) by characterising the properties of the lm and then evaluated its applicability to p-i-n solar cells though device characterisation. When the performance of the solar cell was correlated with lm properties, it was found that, although it compared unfavourably with mc-Si deposited at higher temperatures, it remained a very promising option. Nonetheless, further development is required to increase the overall eciency of mc-Si exible solar cells.

Effects of the process temperature and rolling speed on the thermal roll-to-roll imprint lithography of flexible polycarbonate film

International Nuclear Information System (INIS)

Sohn, Ki-Ju; Lee, Woo Il; Park, Jae Hong; Jang, Hyun-Ik; Lee, Dong-Eon

2013-01-01

Thermal roll-to-roll imprint lithography (R2RIL) is a simple and low-cost process for the mass production of micro/nanopatterns. However, in that it relies on highly viscous thermoplastic resists, it is limited in its ability to imprint precise patterns at a high speed. Moreover, the concentrated imprint force applied in R2RIL can damage the resist material which is structurally vulnerable at high process temperatures. Therefore, it is important to understand the temperature- and time-dependent characteristics of the resist material as well as the imprinting mechanism when using thermal R2RIL. In this work, the effects of the process temperature and rolling speed on thermal R2RIL of polycarbonate (PC) films were investigated to improve the process efficiency. Micro-scale line patterns were successfully transferred onto PC films from nickel (Ni) mold stamps. Consequently, line patterns with widths in the range of 5–80 µm were achieved at a traveling speed of 28.6 mm s –1 and process temperature of 150 °C, which is just above the glass transition temperature (T g ). In addition, the patterning performance was investigated for different temperatures, rolling speeds and pattern sizes. The imprinted pattern profiles were measured by an alpha-step surface profiler to investigate the patterning performance. The results show that a much better imprint performance was achieved at 150 °C, compared to the result at temperatures below T g . The physical mechanisms of thermal R2RIL on a PC film were studied by a finite-element analysis and the patterning process was successfully demonstrated by a visco-plastic deformation model. (paper)

Experimentally Investigating the Effect of Temperature Differences in the Particle Deposition Process on Solar Photovoltaic (PV Modules

Directory of Open Access Journals (Sweden)

Yu Jiang

2016-10-01

Full Text Available This paper reports an experimental investigation of the dust particle deposition process on solar photovoltaic (PV modules with different surface temperatures by a heating plate to illustrate the effect of the temperature difference (thermophoresis between the module surface and the surrounding air on the dust accumulation process under different operating temperatures. In general, if the temperature of PV modules is increased, the energy conversion efficiency of the modules is decreased. However, in this study, it is firstly found that higher PV module surface temperature differences result in a higher energy output compared with those modules with lower temperature differences because of a reduced accumulation of dust particles. The measured deposition densities of dust particles were found to range from 0.54 g/m2 to 0.85 g/m2 under the range of experimental conditions and the output power ratios were found to increase from 0.861 to 0.965 with the increase in the temperature difference from 0 to 50 °C. The PV module with a higher temperature difference experiences a lower dust density because of the effect of the thermophoresis force arising from the temperature gradient between the module surface and its surrounding air. In addition, dust particles have a significant impact on the short circuit current, as well as the output power. However, the influence of particles on open circuit voltage can be negligible.

New Ultrasonic Controller and Characterization System for Low Temperature Drying Process Intensification

Science.gov (United States)

Andrés, R. R.; Blanco, A.; Acosta, V. M.; Riera, E.; Martínez, I.; Pinto, A.

Process intensification constitutes a high interesting and promising industrial area. It aims to modify conventional processes or develop new technologies in order to reduce energy needs, increase yields and improve product quality. It has been demonstrated by this research group (CSIC) that power ultrasound have a great potential in food drying processes. The effects associated with the application of power ultrasound can enhance heat and mass transfer and may constitute a way for process intensification. The objective of this work has been the design and development of a new ultrasonic system for the power characterization of piezoelectric plate-transducers, as excitation, monitoring, analysis, control and characterization of their nonlinear response. For this purpose, the system proposes a new, efficient and economic approach that separates the effect of different parameters of the process like excitation, medium and transducer parameters and variables (voltage, current, frequency, impedance, vibration velocity, acoustic pressure and temperature) by observing the electrical, mechanical, acoustical and thermal behavior, and controlling the vibrational state.

New insights on SOI Tunnel FETs with low-temperature process flow for CoolCube™ integration

Science.gov (United States)

Diaz Llorente, C.; Le Royer, C.; Batude, P.; Fenouillet-Beranger, C.; Martinie, S.; Lu, C.-M. V.; Allain, F.; Colinge, J.-P.; Cristoloveanu, S.; Ghibaudo, G.; Vinet, M.

2018-06-01

This paper reports the fabrication and electrical characterization of planar SOI Tunnel FETs (TFETs) made using a Low-Temperature (LT) process designed for 3D sequential integration. These proof-of-concept TFETs feature junctions obtained by Solid Phase Epitaxy Regrowth (SPER). Their electrical behavior is analyzed and compared to reference samples (regular process using High-Temperature junction formation, HT). Dual ID-VDS measurements verify that the TFET structures present Band-to-Band tunnelling (BTBT) carrier injection and not Schottky Barrier tunnelling. P-mode operating LT TFETs deliver an ON state current similar to that of the HT reference, opening the door towards optimized devices operating with very low threshold voltage VTH and low supply voltage VDD.

Computer modeling of the process of self-propagating high-temperature synthesis in thin system Ni-Al

International Nuclear Information System (INIS)

Poletayev, G.M.; Starostenkov, M.D.; Denisova, N.F.; Skakov, M.K.

2004-01-01

Full text: The process of synthesis of thermal phases of the system Ni-Al is studied through the method of molecular dynamics. As the object of investigation was chosen two-dimensional crystal, that corresponds to atomic packing laying at the plane of volumetric fcc crystal. Clean Ni was taken as a matrix crystal. A particle of clean Al is packed in the center of matrix block. Beyond the bounds of calculated block crystal packing is repeated with the help of periodical border conditions. The interaction between different pairs of atoms is set by pair potential function of Morse, considering interatomic bonding of the point of the sixth coordinate sphere. The allocation of speeds of atomic function in the system is set through the Boltzmann factor, depending the temperature. When the bicrystal is represented by the ideal atom packing and there are no vacancies , the process of structural adjustment is only observed at the temperature, that is higher than melting point. At that, structural adjustment is observed in circular mechanism of atom allocation, also through the border between phases of clean Ni and Al. As a result, Al particle is transformed, at the border between metals, fields of positional disorder and embryos of intermetallide phases NiAl 2 , Ni 2 Al, Ni 3 Al. The introduction of of free volume through the creation of vacancies significantly lowers the temperature of the beginning of the synthesis process of intermetallide phases. The greatest decrease in temperature to the point of 300 K happens, when the vacancies are located in Ni field of bicrystal, the beginning of the thermo-activation is directly connected with the distance from interphase borders. As the process of thermo-activation continues, vacancies located in Ni matrix right up to seventh neighborhood relatively the border bicrystal. During thermo-activation Al particles enter the field and activate the synthesis process

Low–Cost Bio-Based Carbon Fiber for High-Temperature Processing

Energy Technology Data Exchange (ETDEWEB)

Naskar, Amit K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Akato, Kokouvi M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tran, Chau D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Paul, Ryan M. [GrafTech International Holdings, Inc., Brooklyn Heights, OH (United States); Dai, Xuliang [GrafTech International Holdings, Inc., Brooklyn Heights, OH (United States)

2017-02-01

GrafTech International Holdings Inc. (GTI), worked with Oak Ridge National Laboratory (ORNL) under CRADA No. NFE-15-05807 to develop lignin-based carbon fiber (LBCF) technology and to demonstrate LBCF performance in high-temperature products and applications. This work was unique and different from other reported LBCF work in that this study was application-focused and scalability-focused. Accordingly, the executed work was based on meeting criteria based on technology development, cost, and application suitability. The focus of this work was to demonstrate lab-scale LBCF from at least 4 different precursor feedstock sources that could meet the estimated production cost of $5.00/pound and have ash level of less than 500 ppm in the carbonized insulation-grade fiber. Accordingly, a preliminary cost model was developed based on publicly available information. The team demonstrated that 4 lignin samples met the cost criteria, as highlighted in Table 1. In addition, the ash level for the 4 carbonized lignin samples were below 500 ppm. Processing asreceived lignin to produce a high purity lignin fiber was a significant accomplishment in that most industrial lignin, prior to purification, had greater than 4X the ash level needed for this project, and prior to this work there was not a clear path of how to achieve the purity target. The lab scale development of LBCF was performed with a specific functional application in mind, specifically for high temperature rigid insulation. GTI is currently a consumer of foreignsourced pitch and rayon based carbon fibers for use in its high temperature insulation products, and the motivation was that LBCF had potential to decrease costs and increase product competitiveness in the marketplace through lowered raw material costs, lowered energy costs, and decreased environmental footprint. At the end of this project, the Technology Readiness Level (TRL) remained at 5 for LBCF in high temperature insulation.

Collaborative Research: Process-Resolving Decomposition of the Global Temperature Response to Modes of Low Frequency Variability in a Changing Climate

Energy Technology Data Exchange (ETDEWEB)

Deng, Yi [Georgia Inst. of Technology, Atlanta, GA (United States)

2014-11-24

DOE-GTRC-05596 11/24/2104 Collaborative Research: Process-Resolving Decomposition of the Global Temperature Response to Modes of Low Frequency Variability in a Changing Climate PI: Dr. Yi Deng (PI) School of Earth and Atmospheric Sciences Georgia Institute of Technology 404-385-1821, yi.deng@eas.gatech.edu El Niño-Southern Oscillation (ENSO) and Annular Modes (AMs) represent respectively the most important modes of low frequency variability in the tropical and extratropical circulations. The projection of future changes in the ENSO and AM variability, however, remains highly uncertain with the state-of-the-science climate models. This project conducted a process-resolving, quantitative evaluations of the ENSO and AM variability in the modern reanalysis observations and in climate model simulations. The goal is to identify and understand the sources of uncertainty and biases in models’ representation of ENSO and AM variability. Using a feedback analysis method originally formulated by one of the collaborative PIs, we partitioned the 3D atmospheric temperature anomalies and surface temperature anomalies associated with ENSO and AM variability into components linked to 1) radiation-related thermodynamic processes such as cloud and water vapor feedbacks, 2) local dynamical processes including convection and turbulent/diffusive energy transfer and 3) non-local dynamical processes such as the horizontal energy transport in the oceans and atmosphere. In the past 4 years, the research conducted at Georgia Tech under the support of this project has led to 15 peer-reviewed publications and 9 conference/workshop presentations. Two graduate students and one postdoctoral fellow also received research training through participating the project activities. This final technical report summarizes key scientific discoveries we made and provides also a list of all publications and conference presentations resulted from research activities at Georgia Tech. The main findings include

Ceramic stabilization of hazardous wastes: a high performance room temperature process

International Nuclear Information System (INIS)

Maloney, M.D.

1996-01-01

ANL has developed a room-temperature process for converting hazardous materials to a ceramic structure. It is similar to vitrification but is achieved at low cost, similar to conventional cement stabilization. The waste constituents are both chemically stabilized and physically encapsulated, producing very low leaching levels and the potential for delisting. The process, which is pH-insensitive, is ideal for inorganic sludges and liquids, as well as mixed chemical-radioactive wastes, but can also handle significant percentages of salts and even halogenated organics. High waste loadings are possible and densification occurs,so that volumes are only slightly increased and in some cases (eg, incinerator ash) are reduced. The ceramic product has strength and weathering properties far superior to cement products

Processing, microstructure, and electric properties of buried resistors in low-temperature co-fired ceramics

International Nuclear Information System (INIS)

Yang, Pin; Rodriguez, Mark A.; Kotula, Paul; Miera, Brandon K.; Dimos, Duane

2001-01-01

The electrical properties of ruthenium oxide based devitrifiable resistors embedded within low-temperature co-fired ceramics were investigated from -100 o C to 100 o C. Special attention was given to the processing conditions and their effects on resistance and temperature coefficient of resistance (TCR). Results indicate that within this temperature range the conductance for these buried resistors is limited by tunneling of charge carriers through the thin glass layer between ruthenium oxide particles. A modified version of the tunneling barrier model is proposed to account for the microstructure ripening observed during thermal processing. The model parameters determined from curve fitting show that charging energy (i.e., the energy required for a charge carrier to tunnel through the glass barrier) is strongly dependent on particle size and particle--particle separation between ruthenium oxide grains. Initial coarsening of ruthenium oxide grains was found to reduce the charging energy and lower the resistance. However, when extended ripening occurs, the increase in particle--particle separation increases the charging energy, reduces the tunneling probability and gives rise to a higher resistance. The tradeoff between these two effects results in an optimum microstructure with a minimum resistance and TCR. Furthermore, the TCR of these buried resistors has been shown to be governed by the magnitude of the charging energy. Model parameters determined by our analysis appear to provide quantitative physical interpretations to the microstructural changes in the resistor, which in turn, are controlled by the processing conditions

A Comparative Study of Temperature Optimal Control in a Solid State Fermentation Process for Edible Mushroom Growing

Directory of Open Access Journals (Sweden)

K. J. Gurubel

2017-04-01

Full Text Available In this paper, optimal control strategies for temperature trajectory determination in order to maximize thermophilic bacteria in a fed-batch solid-state fermentation reactor are proposed. This process is modeled by nonlinear differential equations, which has been previously validated experimentally with scale reactor temperature profiles. The dynamic input aeration rate of the reactor is determined to increase microorganisms growth of a selective substrate for edible mushroom cultivation. In industrial practice, the process is comprised of three thermal stages with constant input air flow and three types of microorganisms in a 150-hour lapse. Scytalidium thermophilum and actinobacteria are desired in order to obtain a final biomass composition with acceptable microorganisms concentration. The Steepest Descent gradient algorithm in continuous time and the Gradient Projection algorithm in discrete-time are used for the process optimal control. A comparison of simulation results in the presence of disturbances is presented, where the resulting temperature trajectories exhibit similar tendencies as industrial data.

Parsing multiple processes of high temperature impacts on corn/soybean yield using a newly developed CLM-APSIM modeling framework

Science.gov (United States)

Peng, B.; Guan, K.; Chen, M.

2016-12-01

Future agricultural production faces a grand challenge of higher temperature under climate change. There are multiple physiological or metabolic processes of how high temperature affects crop yield. Specifically, we consider the following major processes: (1) direct temperature effects on photosynthesis and respiration; (2) speed-up growth rate and the shortening of growing season; (3) heat stress during reproductive stage (flowering and grain-filling); (4) high-temperature induced increase of atmospheric water demands. In this work, we use a newly developed modeling framework (CLM-APSIM) to simulate the corn and soybean growth and explicitly parse the above four processes. By combining the strength of CLM in modeling surface biophysical (e.g., hydrology and energy balance) and biogeochemical (e.g., photosynthesis and carbon-nitrogen interactions), as well as that of APSIM in modeling crop phenology and reproductive stress, the newly developed CLM-APSIM modeling framework enables us to diagnose the impacts of high temperature stress through different processes at various crop phenology stages. Ground measurements from the advanced SoyFACE facility at University of Illinois is used here to calibrate, validate, and improve the CLM-APSIM modeling framework at the site level. We finally use the CLM-APSIM modeling framework to project crop yield for the whole US Corn Belt under different climate scenarios.

Seasonal Temperature Variations controlling Cave Ventilation Processes in Cueva Larga, Puerto Rico

Science.gov (United States)

Winter, A.; Vieten, R.; Warken, S. F.; Schrӧder-Ritzrau, A.; Miller, T. E.; Scholz, D.

2016-12-01

Two years of monthly monitoring result in much better understanding of ventilation processes in caves. Cueva Larga, a tropical cave in Puerto Rico is 1440 m long with a large main passage (about 116,000 m3). Cave air pCO2 in the main passage varied seasonally, between 600 ppm in winter and 1800 ppm in summer. The seasonal variability in cave pCO2 made it possible to estimate a cave air exchange time of 36±5 days and a winter ventilation rate of 3,200±800 m3/day for the main cave passage. Calculations of virtual temperature and differences between cave and surface temperature show that the seasonal temperature cycle is the main driver of the alternation between a well-ventilated winter mode and a near-stagnant summer mode. The winter mode is characterized by a positive buoyancy contrast at night leading to maximal cave ventilation, while during summer ventilation is at a minimum. Between winter and summer, a transitional mode of partial cave ventilation is observed. On shorter time scales (diurnal to weekly), cave pCO2 is also influenced by atmospheric pressure but this variation is one order of magnitude lower than the seasonal pCO2 change. The cave morphology of Cueva Larga including its large volume, tubular shape and the obstructed cave entrance geometry are important boundary conditions for the observed ventilation patterns. Our findings emphasize that cave systems with varying morphology have to be studied individually in order to correctly describe ventilation processes.

Permanent antistatic phthalocyanine/epoxy nanocomposites – Influence of crosslinking agent, solvent and processing temperature

NARCIS (Netherlands)

Yuan, M.; Brokken-Zijp, J.C.M.; With, de G.

2010-01-01

Cross-linked epoxy matrices containing small amounts of semi-conductive phthalocyanine (Phthalcon) nanoparticles were prepared using different crosslinking agents and processing temperatures. A starting mixture containing an optimum dispersion of these nanoparticles and with an almost equal and

The temperature gradient on section of casting in process of primary crystallization of chromium cast iron

Directory of Open Access Journals (Sweden)

A. Studnicki

2008-08-01

Full Text Available The methodology of defining in article was introduced the temperature gradient in process of primary crystallization during cooling the casting from chromium cast iron on basis of measurements of thermal field in test DTA-K3. Insert also the preliminary results of investigations of influence temperature gradient on structure of studied wear resistance chromium cast iron.

Development of a Mini-Freeze Dryer for Material-Sparing Laboratory Processing with Representative Product Temperature History.

Science.gov (United States)

Obeidat, Wasfy M; Sahni, Ekneet; Kessler, William; Pikal, Michael

2018-02-01

The goal of the work described in this publication was to evaluate a new, small, material-sparing freeze dryer, denoted as the "mini-freeze dryer or mini-FD", capable of reproducing the product temperature history of larger freeze dryers, thereby facilitating scale-up. The mini-FD wall temperatures can be controlled to mimic loading procedures and dryer process characteristics of larger dryers. The mini-FD is equipped with a tunable diode laser absorption spectroscopy (TDLAS) water vapor mass flow monitor and with other advanced process analytical technology (PAT) sensors. Drying experiments were performed to demonstrate scalability to larger freeze dryers, including the determination of vial heat transfer coefficients, K v . Product temperature histories during K v runs were evaluated and compared with those obtained with a commercial laboratory-scale freeze dryer (LyoStar II) for sucrose and mannitol product formulations. When the mini-FD wall temperature was set at the LyoStar II band temperature (- 20°C) to mimic lab dryer edge vials, edge vial drying in the mini-FD possessed an average K v within 5% of those obtained during drying in the LyoStar II. When the wall temperature of the mini-FD was set equal to the central vial product temperature, edge vials behaved as center vials, possessing a K v value within 5% of those measured in the LyoStar II. During both K v runs and complete product freeze drying runs, the temperature-time profiles for the average edge vials and central vial in the mini-FD agreed well with the average edge and average central vials of the LyoStar II.

Development of strategies for saving energy by temperature reduction in warm forging processes

Science.gov (United States)

Varela, Sonia; Santos, Maite; Vadillo, Leire; Idoyaga, Zuriñe; Valbuena, Óscar

2016-10-01

This paper is associated to the European policy of increasing efficiency in raw material and energy usage. This policy becomes even more important in sectors consuming high amount of resources, like hot forging industry, where material costs sums up to 50% of component price and energy ones are continuously raising. The warm forging shows a clear potential of raw material reduction (near-net-shape components) and also of energy saving (forging temperature under 1000°C). However and due to the increment of the energy costs, new solutions are required by the forging sector in order to reduce the temperature below 900°C. The reported research is based on several approaches to reduce the forging temperature applied to a flanged shaft of the automotive sector as demonstration case. The developed investigations have included several aspects: raw material, process parameters, tools and dies behavior during forging process and also metallographic evaluation of the forged parts. This paper summarizes analysis of the ductility and the admissible forces of the flanged shaft material Ck45 in as-supplied state (as-rolled) and also in two additional heat treated states. Hot compression and tensile tests using a GLEEBLE 3800C Thermo mechanical simulator have been performed pursuing this target. In the same way, a coupled numerical model based on Finite Element Method (FEM) has been developed to predict the material flow, the forging loads and the stresses on the tools at lower temperature with the new heat treatments of the raw material. In order to validate the previous development, experimental trials at 850 °C and 750 °C were carried out in a mechanical press and the results were very promising.

Stevia rebaudiana Leaves: Effect of Drying Process Temperature on Bioactive Components, Antioxidant Capacity and Natural Sweeteners.

Science.gov (United States)

Lemus-Mondaca, Roberto; Ah-Hen, Kong; Vega-Gálvez, Antonio; Honores, Carolina; Moraga, Nelson O

2016-03-01

Stevia leaves are usually used in dried state and undergo the inevitable effect of drying process that changes the quality characteristics of the final product. The aim of this study was to assess temperature effect on Stevia leaves through analysis of relevant bioactive components, antioxidant capacity and content of natural sweeteners and minerals. The drying process was performed in a convective dryer at constant temperatures ranging from 30 to 80 °C. Vitamin C was determined in the leaves and as expected showed a decrease during drying proportional to temperature. Phenolics and flavonoids were also determined and were found to increase during drying below 50 °C. Antioxidant activity was determined by DPPH and ORAC assays, and the latter showed the highest value at 40 °C, with a better correlation with the phenolics and flavonoids content. The content of eight natural sweeteners found in Stevia leaves was also determined and an increase in the content of seven of the sweeteners, excluding steviol bioside, was found at drying temperature up to 50 °C. At temperatures between 60 and 80 °C the increase in sweeteners content was not significant. Stevia leaves proved to be an excellent source of antioxidants and natural sweeteners.

Processing of Ni30Pt20Ti50 High-Temperature Shape-Memory Alloy Into Thin Rod Demonstrated

Science.gov (United States)

Noebe, Ronald D.; Draper, Susan L.; Biles, Tiffany A.; Leonhardt, Todd

2005-01-01

High-temperature shape-memory alloys (HTSMAs) based on nickel-titanium (NiTi) with significant ternary additions of palladium (Pd), platinum (Pt), gold (Au), or hafnium (Hf) have been identified as potential high-temperature actuator materials for use up to 500 C. These materials provide an enabling technology for the development of "smart structures" used to control the noise, emissions, or efficiency of gas turbine engines. The demand for these high-temperature versions of conventional shape-memory alloys also has been growing in the automotive, process control, and energy industries. However these materials, including the NiPtTi alloys being developed at the NASA Glenn Research Center, will never find widespread acceptance unless they can be readily processed into useable forms.

High-Temperature Structural Analysis of a Small-Scale Prototype of a Process Heat Exchanger (IV) - Macroscopic High-Temperature Elastic-Plastic Analysis -

International Nuclear Information System (INIS)

Song, Kee Nam; Hong, Sung Deok; Park, Hong Yoon

2011-01-01

A PHE (Process Heat Exchanger) is a key component required to transfer heat energy of 950 .deg. C generated in a VHTR (Very High Temperature Reactor) to a chemical reaction that yields a large quantity of hydrogen. A small-scale PHE prototype made of Hastelloy-X was scheduled for testing in a small-scale gas loop at the Korea Atomic Energy Research Institute. In this study, as a part of the evaluation of the high-temperature structural integrity of the PHE prototype, high-temperature structural analysis modeling, and macroscopic thermal and elastic-plastic structural analysis of the PHE prototype were carried out under the gas-loop test conditions as a preliminary qwer123$ study before carrying out the performance test in the gas loop. The results obtained in this study will be used to design the performance test setup for the modified PHE prototype

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)

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.

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

New steady-state microbial community compositions and process performances in biogas reactors induced by temperature disturbances

DEFF Research Database (Denmark)

Luo, Gang; De Francisci, Davide; Kougias, Panagiotis

2015-01-01

that stochastic factors had a minor role in shaping the profile of the microbial community composition and activity in biogas reactors. On the contrary, temperature disturbance was found to play an important role in the microbial community composition as well as process performance for biogas reactors. Although...... three different temperature disturbances were applied to each biogas reactor, the increased methane yields (around 10% higher) and decreased volatile fatty acids (VFAs) concentrations at steady state were found in all three reactors after the temperature disturbances. After the temperature disturbance...... in shaping the profile of the microbial community composition and activity in biogas reactors. New steady-state microbial community profiles and reactor performances were observed in all the biogas reactors after the temperature disturbance....

The modified relaxation time function: A novel analysis technique for relaxation processes. Application to high-temperature molybdenum internal friction peaks

International Nuclear Information System (INIS)

Matteo, C.L.; Lambri, O.A.; Zelada-Lambri, G.I.; Sorichetti, P.A.; Garcia, J.A.

2008-01-01

The modified relaxation time (MRT) function, which is based on a general linear viscoelastic formalism, has several important mathematical properties that greatly simplify the analysis of relaxation processes. In this work, the MRT is applied to the study of the relaxation damping peaks in deformed molybdenum at high temperatures. The dependence of experimental data from these relaxation processes with temperature are adequately described by a Havriliak-Negami (HN) function, and the MRT makes it possible to find a relation between the parameters of the HN function and the activation energy of the process. The analysis reveals that for the relaxation peak appearing at temperatures below 900 K, the physical mechanism is related to a vacancy-diffusion-controlled movement of dislocations. In contrast, when the peak appears at temperatures higher than 900 K, the damping is controlled by a mechanism of diffusion in the low-temperature tail of the peak, and in the high-temperature tail of the peak the creation plus diffusion of vacancies at the dislocation line occurs

Prediction of temperature and HAZ in thermal-based processes with Gaussian heat source by a hybrid GA-ANN model

Science.gov (United States)

Fazli Shahri, Hamid Reza; Mahdavinejad, Ramezanali

2018-02-01

Thermal-based processes with Gaussian heat source often produce excessive temperature which can impose thermally-affected layers in specimens. Therefore, the temperature distribution and Heat Affected Zone (HAZ) of materials are two critical factors which are influenced by different process parameters. Measurement of the HAZ thickness and temperature distribution within the processes are not only difficult but also expensive. This research aims at finding a valuable knowledge on these factors by prediction of the process through a novel combinatory model. In this study, an integrated Artificial Neural Network (ANN) and genetic algorithm (GA) was used to predict the HAZ and temperature distribution of the specimens. To end this, a series of full factorial design of experiments were conducted by applying a Gaussian heat flux on Ti-6Al-4 V at first, then the temperature of the specimen was measured by Infrared thermography. The HAZ width of each sample was investigated through measuring the microhardness. Secondly, the experimental data was used to create a GA-ANN model. The efficiency of GA in design and optimization of the architecture of ANN was investigated. The GA was used to determine the optimal number of neurons in hidden layer, learning rate and momentum coefficient of both output and hidden layers of ANN. Finally, the reliability of models was assessed according to the experimental results and statistical indicators. The results demonstrated that the combinatory model predicted the HAZ and temperature more effective than a trial-and-error ANN model.

Rheology Guided Rational Selection of Processing Temperature To Prepare Copovidone-Nifedipine Amorphous Solid Dispersions via Hot Melt Extrusion (HME).

Science.gov (United States)

Yang, Fengyuan; Su, Yongchao; Zhang, Jingtao; DiNunzio, James; Leone, Anthony; Huang, Chengbin; Brown, Chad D

2016-10-03

The production of amorphous solid dispersions via hot melt extrusion (HME) relies on elevated temperature and prolonged residence time, which can result in potential degradation and decomposition of thermally sensitive components. Herein, the rheological properties of a physical mixture of polymer and an active pharmaceutical ingredient (API) were utilized to guide the selection of appropriate HME processing temperature. In the currently studied copovidone-nifedipine system, a critical temperature, which is substantially lower (∼13 °C) than the melting point of crystalline API, was captured during a temperature ramp examination and regarded as the critical point at which the API could molecularly dissolve into the polymer. Based on the identification of this critical point, various solid dispersions were prepared by HME processing below, at, and above the critical temperature (both below and above the melting temperature (T m ) of crystalline API). In addition, the resultant extrudates along with two control solid dispersions prepared by physical mixing and cryogenic milling were assessed by X-ray diffraction, differential scanning calorimetry, hot stage microscopy, rheology, and solid-state NMR. Physicochemical properties of resultant solid dispersions indicated that the identified critical temperature is sufficient for the polymer-API system to reach a molecular-level mixing, manifested by the transparent and smooth appearance of extrudates, the absence of API crystalline diffraction and melting peaks, dramatically decreased rheological properties, and significantly improved polymer-API miscibility. Once the critical temperature has been achieved, further raising the processing temperature only results in limited improvement of API dispersion, reflected by slightly reduced storage modulus and complex viscosity and limited improvement in miscibility.

Estimation of centerline temperature of the waste form for the rare earth waste generated from pyrochemical process

Energy Technology Data Exchange (ETDEWEB)

Choi, Jung-Hoon, E-mail: mrchoijh@kaeri.re.kr; Eun, Hee-Chul; Lee, Tae-Kyo; Lee, Ki-Rak; Han, Seung-Youb; Jeon, Min-Ku; Park, Hwan-Seo; Ahn, Do-Hee

2017-01-15

Estimation of centerline temperature of nuclear glass waste form for each waste stream is very essential in the period of storage because the centerline temperature being over its glass transition temperature results in the increase of leaching rate of radioactive nuclides due to the devitrification of glass waste form. Here, to verify the effects of waste form diameter and transuranic element content in the rare earth waste on the centerline temperature of the waste form, the surrogate rare earth glass waste generated from pyrochemical process was immobilized with SiO{sub 2}−Al{sub 2}O{sub 3}−B{sub 2}O{sub 3} glass frit system, and thermal properties of the rare earth glass waste form were determined by thermomechanical analysis and thermal conductivity analysis. The estimation of centerline temperature was carried out using the experimental thermal data and steady-state conduction equation in a long and solid cylinder type waste form. It was revealed that thermal stability of waste form in case of 0.3 m diameter was not affected by the TRU content even in the case of 80% TRU recovery ratio in the electrowinning process, meaning that the waste form of 0.3 m diameter is thermally stable due to the low centerline temperature relative to its glass transition temperature of the rare earth glass waste form.

Potential applications of helium-cooled high-temperature reactors to process heat use

International Nuclear Information System (INIS)

Gambill, W.R.; Kasten, P.R.

1981-01-01

High-Temperature Gas-Cooled Reactors (HTRs) permit nuclear energy to be applied to a number of processes presently utilizing fossil fuels. Promising applications of HTRs involve cogeneration, thermal energy transport using molten salt systems, steam reforming of methane for production of chemicals, coal and oil shale liquefaction or gasification, and - in the longer term - energy transport using a chemical heat pipe. Further, HTRs might be used in the more distant future as the energy source for thermochemical hydrogen production from water. Preliminary results of ongoing studies indicate that the potential market for Process Heat HTRs by the year 2020 is about 150 to 250 GW(t) for process heat/cogeneration application, plus approximately 150 to 300 GW(t) for application to fossil conversion processes. HTR cogeneration plants appear attractive in the near term for new industrial plants using large amounts of process heat, possibly for present industrial plants in conjunction with molten-salt energy distribution systems, and also for some fossil conversion processes. HTR reformer systems will take longer to develop, but are applicable to chemicals production, a larger number of fossil conversion processes, and to chemical heat pipes

Low Temperature Synthesis of Metal Oxides by a Supercritical Seed Enhanced Crystallization (SSEC) Process

DEFF Research Database (Denmark)

Jensen, Henrik; Brummerstedt Iversen, Steen; Joensen, Karsten Dan

2006-01-01

A novel method for producing crystalline nanosized metal oxides by a Supercritical Seed Enhanced Crystallization (SSEC) Process has been developed. The process is a modified sol-gel process taking place at temperatures as low as 95 ºC with supercritical CO2 as solvent and polypropylene as seeding...... material. The nanocrystalline product is obtained without having to resort to costly post-reaction processing and the product is obtained directly after the SSEC process. TiO2 powders produced by the SSEC process were shown to have a crystallinity of 60 % and a crystal size of 7.3 ± 2.6 nm....... The crystallinity can be controlled by changing the heating rate of the initial formation of the nanoparticles and the morphology can be altered by changing the process time....

Kinetics of the process of formation and high-temperature oxidation of electrospark coatings on steel

International Nuclear Information System (INIS)

Verkhoturov, A.D.; Chiplik, V.N.; Egorov, F.F.; Lavrenko, V.A.; Podchernyaeva, I.A.; Shemet, V.Z.

1986-01-01

This work is a study of the kinetics of formation and of the heat resistance of electrospark coatings based on the composite TiB 2 -Mo with varying molybdenum content. In the process of electrospark alloying they measured the specific erosion of the anode and the increase in weight of the cathode with an accuracy not worse than 5%. Electrospark coatings of TiB 2 -Mo on steel 45 are marked by improved scaling resistance at temperatures above 900 C. Their scaling resistance and also the effectiveness of the process of electrospark alloying increase with increasing content of the phase B-MoB in the coating because molybdenum borate forms during its high-temperature oxidation. Illustrations and table are included

Biodegradability of poly(butylene succinate-co-butylene adipate) (PBSA) controlled by temperature during the dried-gel process

Science.gov (United States)

Yamazaki, Hana; Maeda, Tomoki; Hotta, Atsushi

Currently there is a growing interest in biodegradable plastics that can be readily degraded into H2O and CO2. Among them, poly(butylene succinate-co-butylene adipate)(PBSA) is one of the mechanically attractive materials that can be biodegraded by surrounding water molecules and microorganisms after the disposal of the plastics. In order to expand the use of PBSA, the proper and effective control of the biodegradability of PBSA should be realized. In this work, the dried-gel process of the PBSA was carefully studied considering the temperature of the process. Three different types of dried PBSA gels were prepared at three different gel-process temperatures. From the biodegradability testing by immersing the PBSA samples in NaOH aq., it was found that the percentage of the weight loss of the PBSA was increased, indicating that the biodegradability was enhanced as the gel preparation temperature became lower. In fact, smaller spherocrystals were observed in PBSA dried at cooler temperature, studied by the scanning electron microscopy (SEM). It was therefore concluded that the microstructures of PBSA could be well controlled by changing the gel preparation temperatures for the precise control of the biodegradability of PBSA. This work was supported by a Grant-in-Aid for Scientific Research (A) (No. 15H02298 to A.H.) and a Grant-in-Aid for Research Activity Start-up (No.15H06586 to T.M.) from JSPS: KAKENHI\\x9D.

Room-temperature solution-processed and metal oxide-free nano-composite for the flexible transparent bottom electrode of perovskite solar cells

Science.gov (United States)

Lu, Haifei; Sun, Jingsong; Zhang, Hong; Lu, Shunmian; Choy, Wallace C. H.

2016-03-01

The exploration of low-temperature and solution-processed charge transporting and collecting layers can promote the development of low-cost and large-scale perovskite solar cells (PVSCs) through an all solution process. Here, we propose a room-temperature solution-processed and metal oxide-free nano-composite composed of a silver nano-network and graphene oxide (GO) flawless film for the transparent bottom electrode of a PVSC. Our experimental results show that the amount of GO flakes play a critical role in forming the flawless anti-corrosive barrier in the silver nano-network through a self-assembly approach under ambient atmosphere, which can effectively prevent the penetration of liquid or gaseous halides and their corrosion against the silver nano-network underneath. Importantly, we simultaneously achieve good work function alignment and surface wetting properties for a practical bottom electrode by controlling the degree of reduction of GO flakes. Finally, flexible PVSC adopting the room-temperature and solution-processed nano-composite as the flexible transparent bottom electrode has been demonstrated on a polyethylene terephthalate (PET) substrate. As a consequence, the demonstration of our room-temperature solution-processed and metal oxide-free flexible transparent bottom electrode will contribute to the emerging large-area flexible PVSC technologies.The exploration of low-temperature and solution-processed charge transporting and collecting layers can promote the development of low-cost and large-scale perovskite solar cells (PVSCs) through an all solution process. Here, we propose a room-temperature solution-processed and metal oxide-free nano-composite composed of a silver nano-network and graphene oxide (GO) flawless film for the transparent bottom electrode of a PVSC. Our experimental results show that the amount of GO flakes play a critical role in forming the flawless anti-corrosive barrier in the silver nano-network through a self

High Temperature- and High Pressure-Processed Garlic Improves Lipid Profiles in Rats Fed High Cholesterol Diets

Science.gov (United States)

Sohn, Chan Wok; Kim, Hyunae; You, Bo Ram; Kim, Min Jee; Kim, Hyo Jin; Lee, Ji Yeon; Sok, Dai-Eun; Kim, Jin Hee; Lee, Kun Jong

2012-01-01

Abstract Garlic protects against degenerative diseases such as hyperlipidemia and cardiovascular diseases. However, raw garlic has a strong pungency, which is unpleasant. In this study, we examined the effect of high temperature/high pressure-processed garlic on plasma lipid profiles in rats. Sprague–Dawley rats were fed a normal control diet, a high cholesterol (0.5% cholesterol) diet (HCD) only, or a high cholesterol diet supplemented with 0.5% high temperature/high pressure-processed garlic (HCP) or raw garlic (HCR) for 10 weeks. The body weights of the rats fed the garlic-supplemented diets decreased, mostly because of reduced fat pad weights. Plasma levels of total cholesterol (TC), low-density lipoprotein cholesterol, and triglyceride (TG) in the HCP and HCR groups decreased significantly compared with those in the HCD group. Additionally, fecal TC and TG increased significantly in the HCP and HCR groups. It is notable that no significant differences in plasma or fecal lipid profiles were observed between the HCP and HCR groups. High temperature/high pressure-processed garlic contained a higher amount of S-allyl cysteine than raw garlic (Pgarlic may be useful as a functional food to improve lipid profiles. PMID:22404600

Optical fiber sensors for process refractometry and temperature measuring based on curved fibers

International Nuclear Information System (INIS)

Willsch, R.; Schwotzer, G.; Haubenreisser, W.; Jahn, J.U.

1986-01-01

Based on U-shape curved multimode fibers with defined bending radii intensity-modulated optical sensors for the determination of refractive index changes in liquids and related measurands (solution concentration, mixing ratio and others) in process-refractometry and for temperature measuring under special environmental conditions have been developed. The optoelectronic transmitting and receiving units are performed in modular technique and can be used in multi-purpose applications. The principles, performance and characteristical properties of these sensors are described and their possibilities of application in process measuring and automation are discussed by some selected examples. (orig.) [de

Optical fiber sensors for process refractometry and temperature measuring based on curved fibers

Energy Technology Data Exchange (ETDEWEB)

Willsch, R; Schwotzer, G; Haubenreisser, W; Jahn, J U

1986-01-01

Based on U-shape curved multimode fibers with defined bending radii intensity-modulated optical sensors for the determination of refractive index changes in liquids and related measurands (solution concentration, mixing ratio and others) in process-refractometry and for temperature measuring under special environmental conditions have been developed. The optoelectronic transmitting and receiving units are performed in modular technique and can be used in multi-purpose applications. The principles, performance and characteristical properties of these sensors are described and their possibilities of application in process measuring and automation are discussed by some selected examples.

Temperature dependence of frequency dispersion in III–V metal-oxide-semiconductor C-V and the capture/emission process of border traps

Energy Technology Data Exchange (ETDEWEB)

Vais, Abhitosh, E-mail: Abhitosh.Vais@imec.be; Martens, Koen; DeMeyer, Kristin [Department of Electrical Engineering, KU Leuven, B-3000 Leuven (Belgium); IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Lin, Han-Chung; Ivanov, Tsvetan; Collaert, Nadine; Thean, Aaron [IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Dou, Chunmeng [Frontier Research Center, Tokyo Institute of Technology, Yokohama 226-8502 (Japan); Xie, Qi; Maes, Jan [ASM International, B-3001 Leuven (Belgium); Tang, Fu; Givens, Michael [ASM International, Phoenix, Arizona 85034-7200 (United States); Raskin, Jean-Pierre [Institute of Information and Communication Technologies, Electronics and Applied Mathematics, Universiteé Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium)

2015-08-03

This paper presents a detailed investigation of the temperature dependence of frequency dispersion observed in capacitance-voltage (C-V) measurements of III-V metal-oxide-semiconductor (MOS) devices. The dispersion in the accumulation region of the capacitance data is found to change from 4%–9% (per decade frequency) to ∼0% when the temperature is reduced from 300 K to 4 K in a wide range of MOS capacitors with different gate dielectrics and III-V substrates. We show that such significant temperature dependence of C-V frequency dispersion cannot be due to the temperature dependence of channel electrostatics, i.e., carrier density and surface potential. We also show that the temperature dependence of frequency dispersion, and hence, the capture/emission process of border traps can be modeled by a combination of tunneling and a “temperature-activated” process described by a non-radiative multi-phonon model, instead of a widely believed single-step elastic tunneling process.

Efficient inverted bulk-heterojunction solar cells from low-temperature processing of amorphous ZnO buffer layers

KAUST Repository

Jagadamma, Lethy Krishnan; Abdelsamie, Maged; El Labban, Abdulrahman; Aresu, Emanuele; Ngongang Ndjawa, Guy Olivier; Anjum, Dalaver H.; Cha, Dong Kyu; Beaujuge, Pierre; Amassian, Aram

2014-01-01

In this report, we demonstrate that solution-processed amorphous zinc oxide (a-ZnO) interlayers prepared at low temperatures (∼100 °C) can yield inverted bulk-heterojunction (BHJ) solar cells that are as efficient as nanoparticle-based ZnO requiring comparably more complex synthesis or polycrystalline ZnO films prepared at substantially higher temperatures (150-400 °C). Low-temperature, facile solution-processing approaches are required in the fabrication of BHJ solar cells on flexible plastic substrates, such as PET. Here, we achieve efficient inverted solar cells with a-ZnO buffer layers by carefully examining the correlations between the thin film morphology and the figures of merit of optimized BHJ devices with various polymer donors and PCBM as the fullerene acceptor. We find that the most effective a-ZnO morphology consists of a compact, thin layer with continuous substrate coverage. In parallel, we emphasize the detrimental effect of forming rippled surface morphologies of a-ZnO, an observation which contrasts with results obtained in polycrystalline ZnO thin films, where rippled morphologies have been reported to improve efficiency. After optimizing the a-ZnO morphology at low processing temperature for inverted P3HT:PCBM devices, achieving a power conversion efficiency (PCE) of ca. 4.1%, we demonstrate inverted solar cells with low bandgap polymer donors on glass/flexible PET substrates: PTB7:PC71BM (PCE: 6.5% (glass)/5.6% (PET)) and PBDTTPD:PC71BM (PCE: 6.7% (glass)/5.9% (PET)). Finally, we show that a-ZnO based inverted P3HT:PCBM BHJ solar cells maintain ca. 90-95% of their initial PCE even after a full year without encapsulation in a nitrogen dry box, thus demonstrating excellent shelf stability. The insight we have gained into the importance of surface morphology in amorphous zinc oxide buffer layers should help in the development of other low-temperature solution-processed metal oxide interlayers for efficient flexible solar cells. This journal is

Preliminary conceptual design for the destruction of organic/ferrocyanide constituents in the Hanford tank waste with low-temperature hydrothermal processing

International Nuclear Information System (INIS)

Schmidt, A.J.; Jones, E.O.; Orth, R.J.; Cox, J.L.; Elmore, M.E.; Neuenschwander, G.G.; Hart, T.R.; Meng, C.D.

1993-05-01

Hydrothermal processing (HTP) is a thermal-chemical processing method that can be employed to destroy organic and ferrocyanide constituents in Hanford tank waste by using the abundant existing oxidants in the tank waste such as nitrite and nitrate. Use-temperature HTP effectively destroys organics at temperatures from 250 degree C to 400 degree C to eliminate safety hazards and improve further processing. This proposal describes a conceptual design of a low-temperature HTP system (including a preliminary flow diagram and plot plan, equipment descriptions and sizes, utility requirements, and costs); the experimental work supporting this effort at Pacific Northwest Laboratory (PNL); the reaction chemistry and kinetics; the technical maturity of the process; and a preliminary assessment of maintenance, operation, and safety of a system. Nitrate destruction using organic reductants is also described. The low-temperature hydrothermal program at PNL was initiated in January 1993. It is part of an overall program to develop organic destruction technologies, which was originally funded by Hanford's Tank Waste Remediation System program and then was transferred to the Initial Pretreatment (IPM) project. As described in the document, low-temperature HTP (1) meets or exceeds system requirements in organic, ferrocyanide, and nitrate destruction, and processing rate; (2) is technically mature with little additional technology development required; (3) is a simple process with good operational reliability; (4) is flexible and can be easily integrated in the system; (5) has reasonable costs and utility requirements; and (6) is safe and environmentally-benign

Large eddy simulation of the low temperature ignition and combustion processes on spray flame with the linear eddy model

Science.gov (United States)

Wei, Haiqiao; Zhao, Wanhui; Zhou, Lei; Chen, Ceyuan; Shu, Gequn

2018-03-01

Large eddy simulation coupled with the linear eddy model (LEM) is employed for the simulation of n-heptane spray flames to investigate the low temperature ignition and combustion process in a constant-volume combustion vessel under diesel-engine relevant conditions. Parametric studies are performed to give a comprehensive understanding of the ignition processes. The non-reacting case is firstly carried out to validate the present model by comparing the predicted results with the experimental data from the Engine Combustion Network (ECN). Good agreements are observed in terms of liquid and vapour penetration length, as well as the mixture fraction distributions at different times and different axial locations. For the reacting cases, the flame index was introduced to distinguish between the premixed and non-premixed combustion. A reaction region (RR) parameter is used to investigate the ignition and combustion characteristics, and to distinguish the different combustion stages. Results show that the two-stage combustion process can be identified in spray flames, and different ignition positions in the mixture fraction versus RR space are well described at low and high initial ambient temperatures. At an initial condition of 850 K, the first-stage ignition is initiated at the fuel-lean region, followed by the reactions in fuel-rich regions. Then high-temperature reaction occurs mainly at the places with mixture concentration around stoichiometric mixture fraction. While at an initial temperature of 1000 K, the first-stage ignition occurs at the fuel-rich region first, then it moves towards fuel-richer region. Afterwards, the high-temperature reactions move back to the stoichiometric mixture fraction region. For all of the initial temperatures considered, high-temperature ignition kernels are initiated at the regions richer than stoichiometric mixture fraction. By increasing the initial ambient temperature, the high-temperature ignition kernels move towards richer

Treatment of Fungal Bioaerosols by a High-Temperature, Short-Time Process in a Continuous-Flow System▿

Science.gov (United States)

Jung, Jae Hee; Lee, Jung Eun; Lee, Chang Ho; Kim, Sang Soo; Lee, Byung Uk

2009-01-01

Airborne fungi, termed fungal bioaerosols, have received attention due to the association with public health problems and the effects on living organisms in nature. There are growing concerns that fungal bioaerosols are relevant to the occurrence of allergies, opportunistic diseases in hospitals, and outbreaks of plant diseases. The search for ways of preventing and curing the harmful effects of fungal bioaerosols has created a high demand for the study and development of an efficient method of controlling bioaerosols. However, almost all modern microbiological studies and theories have focused on microorganisms in liquid and solid phases. We investigated the thermal heating effects on fungal bioaerosols in a continuous-flow environment. Although the thermal heating process has long been a traditional method of controlling microorganisms, the effect of a continuous high-temperature, short-time (HTST) process on airborne microorganisms has not been quantitatively investigated in terms of various aerosol properties. Our experimental results show that the geometric mean diameter of the tested fungal bioaerosols decreased when they were exposed to increases in the surrounding temperature. The HTST process produced a significant decline in the (1→3)-β-d-glucan concentration of fungal bioaerosols. More than 99% of the Aspergillus versicolor and Cladosporium cladosporioides bioaerosols lost their culturability in about 0.2 s when the surrounding temperature exceeded 350°C and 400°C, respectively. The instantaneous exposure to high temperature significantly changed the surface morphology of the fungal bioaerosols. PMID:19201954

Treatment of fungal bioaerosols by a high-temperature, short-time process in a continuous-flow system.

Science.gov (United States)

Jung, Jae Hee; Lee, Jung Eun; Lee, Chang Ho; Kim, Sang Soo; Lee, Byung Uk

2009-05-01

Airborne fungi, termed fungal bioaerosols, have received attention due to the association with public health problems and the effects on living organisms in nature. There are growing concerns that fungal bioaerosols are relevant to the occurrence of allergies, opportunistic diseases in hospitals, and outbreaks of plant diseases. The search for ways of preventing and curing the harmful effects of fungal bioaerosols has created a high demand for the study and development of an efficient method of controlling bioaerosols. However, almost all modern microbiological studies and theories have focused on microorganisms in liquid and solid phases. We investigated the thermal heating effects on fungal bioaerosols in a continuous-flow environment. Although the thermal heating process has long been a traditional method of controlling microorganisms, the effect of a continuous high-temperature, short-time (HTST) process on airborne microorganisms has not been quantitatively investigated in terms of various aerosol properties. Our experimental results show that the geometric mean diameter of the tested fungal bioaerosols decreased when they were exposed to increases in the surrounding temperature. The HTST process produced a significant decline in the (1-->3)-beta-d-glucan concentration of fungal bioaerosols. More than 99% of the Aspergillus versicolor and Cladosporium cladosporioides bioaerosols lost their culturability in about 0.2 s when the surrounding temperature exceeded 350 degrees C and 400 degrees C, respectively. The instantaneous exposure to high temperature significantly changed the surface morphology of the fungal bioaerosols.

Volatilization and trapping of ruthenium in high temperature processes

International Nuclear Information System (INIS)

Klein, M.; Weyers, C.; Goossens, W.R.A.

1983-01-01

This experimental study has indicated the importance of moisture and NO/sub x/ vapors on the volatility and trapping conditions of ruthenium in high temperature processes. Also the process operating conditions have a great influence on the ruthenium behavior in the off-gas purification units. Of particular interest is the observation that the ruthenium release during direct vitrification of simulated high-level liquid waste is a factor of about 5 smaller than the ruthenium release during calcination of this type of waste. Moreover, in the direct vitrification case the ruthenium escapes mostly in the form of an aerosol whereas in the calcination case a volatile ruthenium compound is dominating. Consequently, a specific ruthenium filter is not needed in the off-gas line of a direct vitrifier simplifying in this way the number of units in this off-gas line and avoiding the handling and controlling problems of such a ruthenium filter. In the future, a similar program will be started on the volatility of cesium and antimony in a liquid fed melter and on the technical reliability of the liquid fed melter and its associated gas purification units on a semi-pilote scale under simulated conditions

Coal gasification coal by steam using process heat from high-temperature nuclear reactors

International Nuclear Information System (INIS)

Heek, K.H. van; Juentgen, H.; Peters, W.

1982-01-01

This paper outlines the coal gasification process using a high-temperature nuclear reactor as a source of the process heat needed. Compared to conventional gasification processes coal is saved by 30-40%, coal-specific emissions are reduced and better economics of gas production are achieved. The introductory chapter deals with motives, aims and tasks of the development, followed by an explanation of the status of investigations, whereby especially the results of a semi-technical pilot plant operated by Bergbau-Forschung are given. Furthermore, construction details of a full-scale commercial gasifier are discussed, including the development of suitable alloys for the heat exchanger. Moreover problems of safety, licensing and economics of future plants have been investigated. (orig.) [de

Infrared temperature measurement and interference analysis of magnesium alloys in hybrid laser-TIG welding process

International Nuclear Information System (INIS)

Huang, R.-S.; Liu, L.-M.; Song, G.

2007-01-01

Infrared (IR) temperature measurement, as a convenient, non-contact method for making temperature field measurements, has been widely used in the fields of welding, but the problem of interference from radiant reflection is a complicating factor in applying IR temperature sensing to welding. The object of this research is to make a deep understand about the formation of interference, explore a new method to eliminate the interfering radiation during laser-TIG hybrid welding of magnesium alloys and to obtain the distribution of temperature field accurately. The experimental results showed that the interferences caused by radiant specular reflection of arc light, ceramic nozzle, electrode and laser nozzle were transferred out of welding seam while the IR thermography system was placed perpendicularly to welding seam. And the welding temperature distribution captured by IR termography system which had been calibrated by thermocouple was reliable by using this method in hybrid laser-TIG welding process of AZ31B magnesium alloy

The effect of increased centrifugation temperature on the quality of red-blood-cell concentrates of automated whole blood processing.

Science.gov (United States)

Weinigel, C; Rummler, S; Barz, D

2013-10-01

There are manual and automated methods to separate whole blood (WB) available. The Atreus whole blood processing system is an automated method, which combines centrifugation and expression of components into a single device. A major difference to conventional methods is that centrifugation temperature is not controlled at 22°C. The aim of this study was to examine the influence of increased centrifugation temperatures on the quality of red-blood-cell concentrates (RCC) after active cooling of WB prior to processing. A total of 28 WB were processed: 16 at centrifugation temperatures of up to 28°C (1st protocol) and 12 at 34°C (2nd protocol). RCC quality parameters were tested weekly for 42 days. Red-blood-cell concentrates (RCC) quality complied with the European and German guidelines. Haemolysis was not significantly different throughout storage. Significant statistical differences were detected between both protocols in potassium concentration at the end of storage and in ATP levels at the day of processing. Centrifugation temperatures of up to 34°C are well tolerated by the red blood cells with minimal interference with the RCC quality parameters. © 2013 International Society of Blood Transfusion.

Sterilization of liquid foods by pulsed electric fields – an innovative ultra-high temperature process

Directory of Open Access Journals (Sweden)

Kai eReineke

2015-05-01

Full Text Available The intention of this study was to investigate the inactivation of endospores by a combined thermal and pulsed electric field (PEF treatment. Therefore, self-cultivated spores of Bacillus subtilis and commercial Geobacillus stearothermophilus spores with certified heat resistance were utilized. Spores of both strains were suspended in saline water (5.3 mS cm-1, skim milk (0.3% fat; 5.3 mS cm-1 and fresh prepared carrot juice (7.73 mS cm-1. The combination of moderate preheating (70-90 °C and an insulated PEF-chamber, combined with a holding tube (65 cm and a heat exchanger for cooling, enabled a rapid heat up to 105-140 °C (measured above the PEF chamber within 92.2-368.9 µs. To compare the PEF process with a pure thermal inactivation, each spore suspension was heat treated in thin glass capillaries and D-values from 90 to 130°C and its corresponding z-values were calculated. For a comparison of the inactivation data, F-values for the temperature fields of both processes were calculated by using Comsol Multiphysics combined with a Matlab routine.A preheating of saline water to 70 °C with a flow rate of 5 l h-1, a frequency of 150 Hz and an energy input of 226.5 kJ kg-1, resulted in a measured outlet temperature of 117 °C and a 4.67 log10 inactivation of Bacillus subtilis. The thermal process with identical F-value caused only a 3.71 log10 inactivation. This synergism of moderate preheating and PEF was even more pronounced for Geobacillus stearothermophilus spores in saline water. A preheating to 95 °C and an energy input of 144 kJ kg-1 resulted in an outlet temperature of 126 °C and a 3.28 log10 inactivation, whereas nearly no inactivation (0.2 log10 was achieved during the thermal treatment.Hence, the PEF technology was evaluated as an alternative ultra-high temperature process. However, for an industrial scale application of this process for sterilization, optimization of the treatment chamber design is needed to reduce the occurring

A two-wavelength imaging pyrometer for measuring particle temperature, velocity and size in thermal spray processes

International Nuclear Information System (INIS)

Craig, J.E.; Parker, R.A.; Lee, D.Y.; Biancaniello, F.; Ridder, S.

1999-01-01

An imaging pyrometer has been developed to measure the surface temperature of hot metal objects and to measure particle temperature, velocity and size in thermal spray, spray-fonning and atomization processes. The two-wavelength surface imaging pyrometer provides true temperature measurement with high resolution, even when the surface has emissivity variation caused by roughness or oxidation. The surface imaging pyrometer has been calibrated for use in a material processing lab calibration over the range of 1000 to 3000 deg K, and these results are described. The particle imaging pyrometer has a field of view that spans the entire particle stream in typical thermal spray devices, and provides continuous measurement of the entire particle stream. Particle temperature and velocity are critical parameters for producing high quality spray coatings efficiently and reliably. The software locates the particle streaks in the image, and determines the intensity ratio for each particle streak pair to obtain the temperature. The dimensions of the particle streak image are measured to determine the velocity and size. Because the vision-based sensor samples the entire particle stream in every video frame, the particle temperature, velocity and size data are updated at 30 Hz at all points in the particle stream. Particle measurements in a plasma spray at NIST are described. In this paper, we will describe our experiments with ceramic powders, in which measurements have been made at several positions along the particle stream. The particle data are represented as profiles across the particle stream, histograms of the full particle stream or time histories of the full-stream average. The results are compared and calibrated with other temperature and diagnostic measurement systems. (author)

Creep of crystals: High-temperature deformation processes in metals, ceramics and minerals

Science.gov (United States)

Poirier, J. P.

An introductory text describing high-temperature deformation processes in metals, ceramics, and minerals is presented. Among the specific topics discussed are: the mechanical aspects of crystal deformation; lattice defects; and phenomenological and thermodynamical analysis of quasi-steady-state creep. Consideration is also given to: dislocation creep models; the effect of hydrostatic pressure on deformation; creep polygonization; and dynamic recrystallization. The status of experimental techniques for the study of transformation plasticity in crystals is also discussed.

Similarities and differences among fluid milk products: traditionally produced, extended shelf life and ultrahigh-temperature processed.

Science.gov (United States)

Grabowski, N T; Ahlfeld, B; Brix, A; Hagemann, A; von Münchhausen, C; Klein, G

2013-06-01

Extended shelf life milk is a relatively new kind of fluid milk, generally manufactured by high-temperature treatment and/or micro-filtration. Being advertised as 'pasteurized milk with an extended shelf life', its flavour, compositional quality and labelling was questioned. Extended shelf life (high-temperature treatment), pasteurized ('traditionally produced') and ultrahigh-temperature milk were, therefore, compared at the beginning and end of shelf life. In triangle tests, panellists distinguished clearly between all products. High-temperature treatment milk's flavour was closer to ultrahigh-temperature and traditionally produced milk in the beginning and at the end of shelf life, respectively. Physicochemically and bacteriologically, all three types could be distinguished. Since 'extended shelf life' comprises many process varieties (each affecting flavour differently), consumer information and appropriate package labelling beyond 'long-lasting' is necessary, e.g. by mentioning the heat treatment applied.

Mechanical Behaviour of 304 Austenitic Stainless Steel Processed by Room Temperature Rolling

Science.gov (United States)

Singh, Rahul; Goel, Sunkulp; Verma, Raviraj; Jayaganthan, R.; Kumar, Abhishek

2018-03-01

To study the effect of room temperature rolling on mechanical properties of 304 Austenitic Stainless Steel, the as received 304 ASS was rolled at room temperature for different percentage of plastic deformation (i.e. 30, 50, 70 and 90 %). Microstructural study, tensile and hardness tests were performed in accordance with ASTM standards to study the effect of rolling. The ultimate tensile strength (UTS) and hardness of a rolled specimen have enhanced with rolling. The UTS has increased from 693 MPa (as received) to 1700 MPa (after 90% deformation). The improvement in UTS of processed samples is due to combined effect of grain refinement and stress induced martensitic phase transformation. The hardness values also increases from 206 VHN (as received) to 499 VHN (after 90% deformation). Magnetic measurements were also conducted to confirm the formation of martensitic phase.

Low-temperature solution processing of palladium/palladium oxide films and their pH sensing performance.

Science.gov (United States)

Qin, Yiheng; Alam, Arif U; Pan, Si; Howlader, Matiar M R; Ghosh, Raja; Selvaganapathy, P Ravi; Wu, Yiliang; Deen, M Jamal

2016-01-01

Highly sensitive, easy-to-fabricate, and low-cost pH sensors with small dimensions are required to monitor human bodily fluids, drinking water quality and chemical/biological processes. In this study, a low-temperature, solution-based process is developed to prepare palladium/palladium oxide (Pd/PdO) thin films for pH sensing. A precursor solution for Pd is spin coated onto pre-cleaned glass substrates and annealed at low temperature to generate Pd and PdO. The percentages of PdO at the surface and in the bulk of the electrodes are correlated to their sensing performance, which was studied by using the X-ray photoelectron spectroscope. Large amounts of PdO introduced by prolonged annealing improve the electrode's sensitivity and long-term stability. Atomic force microscopy study showed that the low-temperature annealing results in a smooth electrode surface, which contributes to a fast response. Nano-voids at the electrode surfaces were observed by scanning electron microscope, indicating a reason for the long-term degradation of the pH sensitivity. Using the optimized annealing parameters of 200°C for 48 h, a linear pH response with sensitivity of 64.71±0.56 mV/pH is obtained for pH between 2 and 12. These electrodes show a response time shorter than 18 s, hysteresis less than 8 mV and stability over 60 days. High reproducibility in the sensing performance is achieved. This low-temperature solution-processed sensing electrode shows the potential for the development of pH sensing systems on flexible substrates over a large area at low cost without using vacuum equipment. Copyright © 2015 Elsevier B.V. All rights reserved.

Optimization of Process Parameters During End Milling and Prediction of Work Piece Temperature Rise

Directory of Open Access Journals (Sweden)

Bhirud N.L.

2017-09-01

Full Text Available During the machining processes, heat gets generated as a result of plastic deformation of metal and friction along the tool–chip and tool–work piece interface. In materials having high thermal conductivity, like aluminium alloys, large amount of this heat is absorbed by the work piece. This results in the rise in the temperature of the work piece, which may lead to dimensional inaccuracies, surface damage and deformation. So, it is needed to control rise in the temperature of the work piece. This paper focuses on the measurement, analysis and prediction of work piece temperature rise during the dry end milling operation of Al 6063. The control factors used for experimentation were number of flutes, spindle speed, depth of cut and feed rate. The Taguchi method was employed for the planning of experimentation and L18 orthogonal array was selected. The temperature rise of the work piece was measured with the help of K-type thermocouple embedded in the work piece. Signal to noise (S/N ratio analysis was carried out using the lower-the-better quality characteristics. Depth of cut was identified as the most significant factor affecting the work piece temperature rise, followed by spindle speed. Analysis of variance (ANOVA was employed to find out the significant parameters affecting the work piece temperature rise. ANOVA results were found to be in line with the S/N ratio analysis. Regression analysis was used for developing empirical equation of temperature rise. The temperature rise of the work piece was calculated using the regression equation and was found to be in good agreement with the measured values. Finally, confirmation tests were carried out to verify the results obtained. From the confirmation test it was found that the Taguchi method is an effective method to determine optimised parameters for minimization of work piece temperature.

Generation of low-temperature air plasma for food processing

Science.gov (United States)

Stepanova, Olga; Demidova, Maria; Astafiev, Alexander; Pinchuk, Mikhail; Balkir, Pinar; Turantas, Fulya

2015-11-01

The project is aimed at developing a physical and technical foundation of generating plasma with low gas temperature at atmospheric pressure for food industry needs. As known, plasma has an antimicrobial effect on the numerous types of microorganisms, including those that cause food spoilage. In this work an original experimental setup has been developed for the treatment of different foods. It is based on initiating corona or dielectric-barrier discharge in a chamber filled with ambient air in combination with a certain helium admixture. The experimental setup provides various conditions of discharge generation (including discharge gap geometry, supply voltage, velocity of gas flow, content of helium admixture in air and working pressure) and allows for the measurement of the electrical discharge parameters. Some recommendations on choosing optimal conditions of discharge generation for experiments on plasma food processing are developed.

Flavanols, proanthocyanidins and antioxidant activity changes during cocoa (Theobroma cacao L.) roasting as affected by temperature and time of processing.

Science.gov (United States)

Ioannone, F; Di Mattia, C D; De Gregorio, M; Sergi, M; Serafini, M; Sacchetti, G

2015-05-01

The effect of roasting on the content of flavanols and proanthocyanidins and on the antioxidant activity of cocoa beans was investigated. Cocoa beans were roasted at three temperatures (125, 135 and 145 °C), for different times, to reach moisture contents of about 2 g 100 g(-1). Flavanols and proanthocyanidins were determined, and the antioxidant activity was tested by total phenolic index (TPI), ferric reducing antioxidant power (FRAP) and total radical trapping antioxidant parameter (TRAP) methods. The rates of flavanol and total proanthocyanidin loss increased with roasting temperatures. Moisture content of the roasted beans being equal, high temperature-short time processes minimised proanthocyanidins loss. Moisture content being equal, the average roasting temperature (135 °C) determined the highest TPI and FRAP values and the highest temperature (145 °C) determined the lowest TPI values. Moisture content being equal, low temperature-long time roasting processes maximised the chain-breaking activity, as determined by the TRAP method. Copyright © 2014 Elsevier Ltd. All rights reserved.

Complete FDTD analysis of microwave heating processes in frequency-dependent and temperature dependent media

Energy Technology Data Exchange (ETDEWEB)

Torres, F.; Jecko, B. [Univ. de Limoges (France). Inst. de Recherche en Communications Optiques et Microondes

1997-01-01

It is well known that the temperature rise in a material modifies its physical properties and, particularly, its dielectric permittivity. The dissipated electromagnetic power involved in microwave heating processes depending on {var_epsilon}({omega}), the electrical characteristics of the heated media must vary with the temperature to achieve realistic simulations. In this paper, the authors present a fast and accurate algorithm allowing, through a combined electromagnetic and thermal procedure, to take into account the influence of the temperature on the electrical properties of materials. First, the temperature dependence of the complex permittivity ruled by a Debye relaxation equation is investigated, and a realistic model is proposed and validated. Then, a frequency-dependent finite-differences time-domain ((FD){sup 2}TD) method is used to assess the instantaneous electromagnetic power lost by dielectric hysteresis. Within the same iteration, a time-scaled form of the heat transfer equation allows one to calculate the temperature distribution in the heated medium and then to correct the dielectric properties of the material using the proposed model. These new characteristics will be taken into account by the EM solver at the next iteration. This combined algorithm allows a significant reduction of computation time. An application to a microwave oven is proposed.

A Short review on wrought austenitic stainless steels at high temperatures: processing, microstructure, properties and performance

Directory of Open Access Journals (Sweden)

Ronald Lesley Plaut

2007-12-01

Full Text Available Wrought austenitic stainless steels are widely used in high temperature applications. This short review discusses initially the processing of this class of steels, with emphasis on solidification and hot working behavior. Following, a brief summary is made on the precipitation behavior and the numerous phases that may appear in their microstructures. Creep and oxidation resistance are, then, briefly discussed, and finalizing their performance is compared with other high temperature metallic materials.

Effect of temperature and active biogas process on passive separation of digested manure

DEFF Research Database (Denmark)

Kaparaju, Prasad Laxmi-Narasimha; Angelidaki, Irini

2008-01-01

The objective of the study was to identify the optimum time interval for effluent removal after temporarily stopping stirring in otherwise continuously stirred tank reactors. Influence of temperature (10 and 55 degrees C) and active biogas process on passive separation of digested manure, where...... no outside mechanical or chemical action was used, within the reactor was studied in three vertical settling columns (100 cm deep). Variations in solids and microbial distribution at top, middle and bottom layers of column were assessed over a 15 day settling period. Results showed that best solids...... separation was achieved when digested manure was allowed to settle at 55 degrees C with active biogas process (pre-incubated at 55 degrees C) compared to separation at 55 degrees C without active biogas process (autoclaved at 120 degrees C, for 20 min) or at 10 degrees C with active biogas process. Maximum...

Magnetization process and low-temperature thermodynamics of a spin-1/2 Heisenberg octahedral chain

Science.gov (United States)

Strečka, Jozef; Richter, Johannes; Derzhko, Oleg; Verkholyak, Taras; Karľová, Katarína

2018-05-01

Low-temperature magnetization curves and thermodynamics of a spin-1/2 Heisenberg octahedral chain with the intra-plaquette and monomer-plaquette interactions are examined within a two-component lattice-gas model of hard-core monomers, which takes into account all low-lying energy modes in a highly frustrated parameter space involving the monomer-tetramer, localized many-magnon and fully polarized ground states. It is shown that the developed lattice-gas model satisfactorily describes all pronounced features of the low-temperature magnetization process and the magneto-thermodynamics such as abrupt changes of the isothermal magnetization curves, a double-peak structure of the specific heat or a giant magnetocaloric effect.

Simultaneous measurement of current and temperature distributions in a proton exchange membrane fuel cell during cold start processes

International Nuclear Information System (INIS)

Jiao Kui; Alaefour, Ibrahim E.; Karimi, Gholamreza; Li Xianguo

2011-01-01

Cold start is critical to the commercialization of proton exchange membrane fuel cell (PEMFC) in automotive applications. Dynamic distributions of current and temperature in PEMFC during various cold start processes determine the cold start characteristics, and are required for the optimization of design and operational strategy. This study focuses on an investigation of the cold start characteristics of a PEMFC through the simultaneous measurements of current and temperature distributions. An analytical model for quick estimate of purging duration is also developed. During the failed cold start process, the highest current density is initially near the inlet region of the flow channels, then it moves downstream, reaching the outlet region eventually. Almost half of the cell current is produced in the inlet region before the cell current peaks, and the region around the middle of the cell has the best survivability. These two regions are therefore more important than other regions for successful cold start through design and operational strategy, such as reducing the ice formation and enhancing the heat generation in these two regions. The evolution of the overall current density distribution over time remains similar during the successful cold start process; the current density is the highest near the flow channel inlets and generally decreases along the flow direction. For both the failed and the successful cold start processes, the highest temperature is initially in the flow channel inlet region, and is then around the middle of the cell after the overall peak current density is reached. The ice melting and liquid formation during the successful cold start process have negligible influence on the general current and temperature distributions.

Solid state NMR studies for a new carbonization process with high temperature preheating

Science.gov (United States)

Saito, Koji; Hatakeyama, Moriaki; Komaki, Ikuo; Katoh, Kenji

2002-01-01

A new carbonization process with rapid preheating and coke discharging at medium temperature has been developed in Japan. The result of this process shows that even when no or slightly coking coal is by 50 wt% the coking property is improved and a coking coke with cold strength usable at blast furnace can be manufactured with the new carbonization process. The mechanism of the coking property improvement was examined by coal properties using mainly solid state NMR ( 1H CRAMPS and 13C SPE/MAS, CP/MAS) and NMR imaging (single point imaging, in-situ imaging). It has been clarified that the molecular structure of coal is relaxed by the rapid heating treatment and, in addition, there is a close relation between hydrogen bonding and relaxation of the molecular structure of coal.

Transformation of 5-O-caffeoylquinic acid in blueberries during high-temperature processing.

Science.gov (United States)

Dawidowicz, Andrzej L; Typek, Rafal

2014-11-12

Chlorogenic acid (CQA), an ester of caffeic with quinic acid, is a natural compound found in a wide array of plants. Although coffee beans are most frequently mentioned as plant products remarkably rich in CQAs, their significant amounts can also be found in many berries, for example, blueberries. This paper shows and discusses the thermal stability of the main CQA representative, that is, 5-O-caffeoylquinic acid (5-CQA), during high-temperature processing of blueberries (as in the production of blueberry foods) in systems containing sucrose in low and high concentration. It has been found that up to 11 components (5-CQA derivatives and its reaction product with water) can be formed from 5-CQA during the processing of blueberries. Their formation speed depends on the sucrose concentration in the processed system, which has been confirmed in the artificial system composed of 5-CQA water solution containing different amounts of the sugar.

Processes of energy recovery / energy valorization at low temperature levels. State of the art. Extended abstract

International Nuclear Information System (INIS)

Manificat, A.; Megret, O.

2012-09-01

This study aims to realize a state of art of the processes of energy recovery at low level of temperature and their valorizations. The information provided will target particularly the thermal systems of waste and biomass treatment. After reminding the adequate context of development with these solutions and define the scope of the current work, the study begins with the definition of different concepts such as low-grade heat (fatal energy) and exergy, and also the presentation of the fiscal environment as well as the economic and regulatory situation, with information about the TGAP, prices of energy and energy efficiency. The second chapter focuses on the different sources of energy at low temperature level that can be recoverable in order to assess their potentials and their characteristics. The Determination of the temperature range of these energy sources will be put in relation with the needs and demands of users from different industrial sectors. The third part of the study is a review of various technologies for energy recovery and valorization at low temperature. It is useful to distinguish different types of heat exchangers interesting to implement. Moreover, innovative processes allow us to consider new perspectives other than a direct use of heat recovered. For example, we can take into account systems for producing electricity (ORC cycle, hot air engines, thermoelectric conversion), or cold generation (sorption refrigeration machine, Thermo-ejector refrigeration machine) or techniques for energy storage with PCM (Phase Change Material). The last chapter deals to the achievement of four study cases written in the form of sheet and aimed at assess the applicability of the processes previously considered, concerning the field of waste. (authors)

Leaf litter processing in West Virginia mountain streams: effects of temperature and stream chemistry

Science.gov (United States)

Jacquelyn M. Rowe; William B. Perry; Sue A. Perry

1996-01-01

Climate change has the potential to alter detrital processing in headwater streams, which receive the majority of their nutrient input as terrestrial leaf litter. Early placement of experimental leaf packs in streams, one month prior to most abscission, was used as an experimental manipulation to increase stream temperature during leaf pack breakdown. We studied leaf...

Mild-temperature dilute acid pretreatment for integration of first and second generation ethanol processes.

Science.gov (United States)

Nair, Ramkumar B; Kalif, Mahdi; Ferreira, Jorge A; Taherzadeh, Mohammad J; Lennartsson, Patrik R

2017-12-01

The use of hot-water (100°C) from the 1st generation ethanol plants for mild-temperature lignocellulose pretreatment can possibly cut down the operational (energy) cost of 2nd generation ethanol process, in an integrated model. Dilute-sulfuric and -phosphoric acid pretreatment at 100°C was carried out for wheat bran and whole-stillage fibers. Pretreatment time and acid type influenced the release of sugars from wheat bran, while acid-concentration was found significant for whole-stillage fibers. Pretreatment led up-to 300% improvement in the glucose yield compared to only-enzymatically treated substrates. The pretreated substrates were 191-344% and 115-300% richer in lignin and glucan, respectively. Fermentation using Neurospora intermedia, showed 81% and 91% ethanol yields from wheat bran and stillage-fibers, respectively. Sawdust proved to be a highly recalcitrant substrate for mild-temperature pretreatment with only 22% glucose yield. Both wheat bran and whole-stillage are potential substrates for pretreatment using waste heat from the 1st generation process for 2nd generation ethanol. Copyright © 2017 Elsevier Ltd. All rights reserved.

Highly efficient organic solar Cells based on a robust room-temperature solution-processed copper iodide hole transporter

KAUST Repository

Zhao, Kui; Ngongang Ndjawa, Guy Olivier; Jagadamma, Lethy Krishnan; El Labban, Abdulrahman; Hu, Hanlin; Wang, Qingxiao; Li, Ruipeng; Abdelsamie, Maged; Beaujuge, Pierre; Amassian, Aram

2015-01-01

Achieving high performance and reliable organic solar cells hinges on the development of stable and energetically suitable hole transporting buffer layers in tune with the electrode and photoactive materials of the solar cell stack. Here we have identified solution-processed copper(I) iodide (CuI) thin films with low-temperature processing conditions as an effective hole–transporting layer (HTL) for a wide range of polymer:fullerene bulk heterojunction (BHJ) systems. The solar cells using CuI HTL show higher power conversion efficiency (PCE) in standard device structure for polymer blends, up to PCE of 8.8%, as compared with poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) HTL, for a broad range of polymer:fullerene systems. The CuI layer properties and solar cell device behavior are shown to be remarkably robust and insensitive to a wide range of processing conditions of the HTL, including processing solvent, annealing temperature (room temperature up to 200 °C), and film thickness. CuI is also shown to improve the overall lifetime of solar cells in the standard architecture as compared to PEDOT:PSS. We further demonstrate promising solar cell performance when using CuI as top HTL in an inverted device architecture. The observation of uncommon properties, such as photoconductivity of CuI and templating effects on the BHJ layer formation, are also discussed. This study points to CuI as being a good candidate to replace PEDOT:PSS in solution-processed solar cells thanks to the facile implementation and demonstrated robustness of CuI thin films.

Highly efficient organic solar Cells based on a robust room-temperature solution-processed copper iodide hole transporter

KAUST Repository

Zhao, Kui

2015-07-30

Achieving high performance and reliable organic solar cells hinges on the development of stable and energetically suitable hole transporting buffer layers in tune with the electrode and photoactive materials of the solar cell stack. Here we have identified solution-processed copper(I) iodide (CuI) thin films with low-temperature processing conditions as an effective hole–transporting layer (HTL) for a wide range of polymer:fullerene bulk heterojunction (BHJ) systems. The solar cells using CuI HTL show higher power conversion efficiency (PCE) in standard device structure for polymer blends, up to PCE of 8.8%, as compared with poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) HTL, for a broad range of polymer:fullerene systems. The CuI layer properties and solar cell device behavior are shown to be remarkably robust and insensitive to a wide range of processing conditions of the HTL, including processing solvent, annealing temperature (room temperature up to 200 °C), and film thickness. CuI is also shown to improve the overall lifetime of solar cells in the standard architecture as compared to PEDOT:PSS. We further demonstrate promising solar cell performance when using CuI as top HTL in an inverted device architecture. The observation of uncommon properties, such as photoconductivity of CuI and templating effects on the BHJ layer formation, are also discussed. This study points to CuI as being a good candidate to replace PEDOT:PSS in solution-processed solar cells thanks to the facile implementation and demonstrated robustness of CuI thin films.

High-Temperature Structural Analysis Model of the Process Heat Exchanger for Helium Gas Loop (II)

International Nuclear Information System (INIS)

Song, Kee Nam; Lee, Heong Yeon; Kim, Chan Soo; Hong, Seong Duk; Park, Hong Yoon

2010-01-01

PHE (Process Heat Exchanger) is a key component required to transfer heat energy of 950 .deg. C generated in a VHTR (Very High Temperature Reactor) to the chemical reaction that yields a large quantity of hydrogen. Korea Atomic Energy Research Institute established the helium gas loop for the performance test of components, which are used in the VHTR, and they manufactured a PHE prototype to be tested in the loop. In this study, as part of the high temperature structural-integrity evaluation of the PHE prototype, which is scheduled to be tested in the helium gas loop, we carried out high-temperature structural-analysis modeling, thermal analysis, and thermal expansion analysis of the PHE prototype. The results obtained in this study will be used to design the performance test setup for the PHE prototype

Structure engineering of hole-conductor free perovskite-based solar cells with low-temperature-processed commercial carbon paste as cathode.

Science.gov (United States)

Zhang, Fuguo; Yang, Xichuan; Wang, Haoxin; Cheng, Ming; Zhao, Jianghua; Sun, Licheng

2014-09-24

Low-temperature-processed (100 °C) carbon paste was developed as counter electrode material in hole-conductor free perovskite/TiO2 heterojunction solar cells to substitute noble metallic materials. Under optimized conditions, an impressive PCE value of 8.31% has been achieved with this carbon counter electrode fabricated by doctor-blading technique. Electrochemical impedance spectroscopy demonstrates good charge transport characteristics of low-temperature-processed carbon counter electrode. Moreover, this carbon counter electrode-based perovskite solar cell exhibits good stability over 800 h.

Preparation of Microcellular Epoxy Foams through a Limited-Foaming Process: A Contradiction with the Time-Temperature-Transformation Cure Diagram.

Science.gov (United States)

Wang, Lijun; Zhang, Chun; Gong, Wei; Ji, Yubi; Qin, Shuhao; He, Li

2018-01-01

3D cross-linking networks are generated through chemical reactions between thermosetting epoxy resin and hardener during curing. The curing degree of epoxy material can be increased by increasing curing temperature and/or time. The epoxy material must then be fully cured through a postcuring process to optimize its material characteristics. Here, a limited-foaming method is introduced for the preparation of microcellular epoxy foams (Lim-foams) with improved cell morphology, high thermal expansion coefficient, and good compressive properties. Lim-foams exhibit a lower glass transition temperature (T g ) and curing degree than epoxy foams fabricated through free-foaming process (Fre-foams). Surprisingly, however, the T g of Lim-foams is unaffected by postcuring temperature and time. This phenomenon, which is related to high gas pressure in the bubbles, contradicts that indicated by the time-temperature-transformation cure diagram. High bubble pressure promotes the movement of molecular chains under heating at low temperature and simultaneously suppresses the etherification cross-linking reaction during post-curing. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An Octave/MATLAB® Interface for Rapid Processing of SMOS L1C Full Polarization Brightness Temperature

Directory of Open Access Journals (Sweden)

Pablo Saavedra

2018-01-01

Full Text Available A tool to process the SMOS microwave radiometer level 1C polarized brightness temperatures data product has been developed. The SMOS L1C science product contains the dual and full (Stokes vector polarization brightness temperatures at L-band for multiple incidence angles. In order to use the L1C product, the measurements are processed by a number of procedures including radio frequency interference (RFI filters, conversion of the polarization plane from the antenna (X- & Y-pol to the Earth’s surface frame (H- & V-pol, and averaging to fixed classes of incidence angles. The software allows for the processing of data for the entire daily half-orbit product, or for specific regions of interest, and can be adapted as a bash-job to process a large number of data files e.g. for time series analysis. This paper describes the tool which was developed in GNU C++ with the capability to be compiled as MEX function to work with Octave or MATLAB® without any source code adjustment. Funding statement: 'Deutsche Forschungsgemeinschaft' DFG under grant number SI 606/24-1.

High temperature superconductor bulk materials. Fundamentals - processing - properties control - application aspects

International Nuclear Information System (INIS)

Krabbes, G.; Fuchs, G.; Canders, W.R.; May, H.; Palka, R.

2006-01-01

This book presents all the features of bulk high temperature superconducting materials. Starting from physical and chemical fundamentals, the authors move on to portray methods and problems of materials processing, thoroughly working out the characteristic properties of bulk superconductors in contrast to long conductors and films. The authors provide a wide range of specific materials characteristics with respect to the latest developments and future applications guiding from fundamentals to practical engineering examples. This book contains the following chapters: 1. Fundamentals 2. Growth and melt processing of YBCO 3. Pinning-relevant defects in bulk YBCO 4. Properties of bulk YBCO 5. Trapped fields 6. Improved YBCO based bulk superconductors and functional elements 7. Alternative systems 8. Peak effect 9. Very high trapped fields in YBCO permanent magnets 10. Engineering aspects: Field distribution in bulk HTSC 11. Inherently stable superconducting magnetic bearings 12. Application of bulk HTSCs in electromagnetic energy converters 13. Applications in magnet technologies and power supplies

Cluster tool for in situ processing and comprehensive characteriza tion of thin films at high temperatures.

Science.gov (United States)

Wenisch, Robert; Lungwitz, Frank; Hanf, Daniel; Heller, Rene; Zscharschuch, Jens; Hübner, René; von Borany, Johannes; Abrasonis, Gintautas; Gemming, Sibylle; Escobar-Galindo, Ramon; Krause, Matthias

2018-05-31

A new cluster tool for in situ real-time processing and depth-resolved compositional, structural and optical characterization of thin films at temperatures from -100 to 800 °C is described. The implemented techniques comprise magnetron sputtering, ion irradiation, Rutherford backscattering spectrometry, Raman spectroscopy and spectroscopic ellipsometry. The capability of the cluster tool is demonstrated for a layer stack MgO/ amorphous Si (~60 nm)/ Ag (~30 nm), deposited at room temperature and crystallized with partial layer exchange by heating up to 650°C. Its initial and final composition, stacking order and structure were monitored in situ in real time and a reaction progress was defined as a function of time and temperature.

Effect of process parameters on hardness, temperature profile and solidification of different layers processed by direct metal laser sintering (DMLS)

International Nuclear Information System (INIS)

Ahmed, Sazzad Hossain; Mian, Ahsan; Srinivasan, Raghavan

2016-01-01

In DMLS process objects are fabricated layer by layer from powdered material by melting induced by a controlled laser beam. Metallic powder melts and solidifies to form a single layer. Solidification map during layer formation is an important route to characterize micro-structure and grain morphology of sintered layer. Generally, solidification leads to columnar, equiaxed or mixture of these two types grain morphology depending on solidification rate and thermal gradient. Eutectic or dendritic structure can be formed in fully equiaxed zone. This dendritic growth has a large effect on material properties. Smaller dendrites generally increase ductility of the layer. Thus, materials can be designed by creating desired grain morphology in certain regions using DMLS process. To accomplish this, hardness, temperature distribution, thermal gradient and solidification cooling rate in processed layers will be studied under change of process variables by using finite element analysis, with specific application to Ti-6Al-4V.

Effect of process parameters on hardness, temperature profile and solidification of different layers processed by direct metal laser sintering (DMLS)

Science.gov (United States)

Ahmed, Sazzad Hossain; Mian, Ahsan; Srinivasan, Raghavan

2016-07-01

In DMLS process objects are fabricated layer by layer from powdered material by melting induced by a controlled laser beam. Metallic powder melts and solidifies to form a single layer. Solidification map during layer formation is an important route to characterize micro-structure and grain morphology of sintered layer. Generally, solidification leads to columnar, equiaxed or mixture of these two types grain morphology depending on solidification rate and thermal gradient. Eutectic or dendritic structure can be formed in fully equiaxed zone. This dendritic growth has a large effect on material properties. Smaller dendrites generally increase ductility of the layer. Thus, materials can be designed by creating desired grain morphology in certain regions using DMLS process. To accomplish this, hardness, temperature distribution, thermal gradient and solidification cooling rate in processed layers will be studied under change of process variables by using finite element analysis, with specific application to Ti-6Al-4V.

Effect of process parameters on hardness, temperature profile and solidification of different layers processed by direct metal laser sintering (DMLS)

Energy Technology Data Exchange (ETDEWEB)

Ahmed, Sazzad Hossain; Mian, Ahsan, E-mail: ahsan.mian@wright.edu; Srinivasan, Raghavan [Department of Mechanical and Materials Engineering, Wright State University, Dayton, Ohio 45435 (United States)

2016-07-12

In DMLS process objects are fabricated layer by layer from powdered material by melting induced by a controlled laser beam. Metallic powder melts and solidifies to form a single layer. Solidification map during layer formation is an important route to characterize micro-structure and grain morphology of sintered layer. Generally, solidification leads to columnar, equiaxed or mixture of these two types grain morphology depending on solidification rate and thermal gradient. Eutectic or dendritic structure can be formed in fully equiaxed zone. This dendritic growth has a large effect on material properties. Smaller dendrites generally increase ductility of the layer. Thus, materials can be designed by creating desired grain morphology in certain regions using DMLS process. To accomplish this, hardness, temperature distribution, thermal gradient and solidification cooling rate in processed layers will be studied under change of process variables by using finite element analysis, with specific application to Ti-6Al-4V.

Noncontacting acoustics-based temperature measurement techniques in rapid thermal processing

Science.gov (United States)

Lee, Yong J.; Chou, Ching-Hua; Khuri-Yakub, Butrus T.; Saraswat, Krishna C.

1991-04-01

Temperature measurement of silicon wafers based on the temperature dependence of acoustic waves is studied. The change in the temperature-dependent dispersion relations of the plate modes through the wafer can be exploited to provide a viable temperature monitoring scheme with advantages over both thermocouples and pyrometers. Velocity measurements of acoustic waves through a thin layer of ambient directly above the wafer provides the temperature of the wafer-ambient interface. 1.

Modeling the UO2 ex-AUC pellet process and predicting the fuel rod temperature distribution under steady-state operating condition

Science.gov (United States)

Hung, Nguyen Trong; Thuan, Le Ba; Thanh, Tran Chi; Nhuan, Hoang; Khoai, Do Van; Tung, Nguyen Van; Lee, Jin-Young; Jyothi, Rajesh Kumar

2018-06-01

Modeling uranium dioxide pellet process from ammonium uranyl carbonate - derived uranium dioxide powder (UO2 ex-AUC powder) and predicting fuel rod temperature distribution were reported in the paper. Response surface methodology (RSM) and FRAPCON-4.0 code were used to model the process and to predict the fuel rod temperature under steady-state operating condition. Fuel rod design of AP-1000 designed by Westinghouse Electric Corporation, in these the pellet fabrication parameters are from the study, were input data for the code. The predictive data were suggested the relationship between the fabrication parameters of UO2 pellets and their temperature image in nuclear reactor.

Chemical transitions of Areca semen during the thermal processing revealed by temperature-resolved ATR-FTIR spectroscopy and two-dimensional correlation analysis

Science.gov (United States)

Wang, Zhibiao; Wang, Xu; Pei, Wenxuan; Li, Sen; Sun, Suqin; Zhou, Qun; Chen, Jianbo

2018-03-01

Areca semen is a common herb used in traditional Chinese medicine, but alkaloids in this herb are categorized as Group I carcinogens by IARC. It has been proven that the stir-baking process can reduce alkaloids in Areca semen while keep the activity for promoting digestion. However, the changes of compositions other than alkaloids during the thermal processing are unclear. Understanding the thermal chemical transitions of Areca semen is necessary to explore the processing mechanisms and optimize the procedures. In this research, FTIR spectroscopy with a temperature-controlled ATR accessory is employed to study the heating process of Areca semen. Principal component analysis and two-dimensional correlation spectroscopy are used to interpret the spectra to reveal the chemical transitions of Areca semen in different temperature ranges. The loss of a few volatile compounds in the testa and sperm happens below 105 °C, while some esters in the sperm decreases above 105 °C. As the heating temperature is close to 210 °C, Areca semen begins to be scorched and the decomposition of many compounds can be observed. This research shows the potential of the temperature-resolved ATR-FTIR spectroscopy in exploring the chemical transitions of the thermal processing of herbal materials.

The pebble-bed high-temperature reactor as a source of nuclear process heat. Vol. 3

International Nuclear Information System (INIS)

Kugeler, K.; Schulten, R.; Kugeler, M.; Niessen, H.F.; Roeth-Kamat, M.; Hohn, H.; Woike, O.; Germer, J.H.

1974-08-01

The characteristic questions concerning a process heat reactor with high helium outlet temperatures are dealt with in this volume like e.g. fuel element design, corrosion, and fission product release. Furthermore, some possibilities of the technical realization of the hot-gas ducting and intermediate heat exchangers are described. Important parameters for the design of the reactor such as core power density, helium inlet and outlet temperatures, helium pressure and fuel cycle burn-up and conversion and the effect of these on the primary circuit are investigated. The important question regarding which reactor vessel is to be chosen for nuclear process heat plants is discussed with the aid of the integrated and non-integrated concepts using prestressed concrete, cast iron and cast steel. Thereafter, considerations on the safety of the nuclear plant are given. Finally, mention is made of the availability of the nuclear plant and of the status of development of the HTR technology. (orig.) [de

Discharging process of a finned heat pipe–assisted thermal energy storage system with high temperature phase change material

International Nuclear Information System (INIS)

Tiari, Saeed; Qiu, Songgang; Mahdavi, Mahboobe

2016-01-01

Highlights: • The discharging process of a latent heat thermal energy storage system is studied. • The thermal energy storage system is assisted by finned heat pipes. • The influences of heat pipe spacing and fins geometrical features are studied. • Smaller heat pipe spacing enhances the solidification rate. • Better heat pipe and fin arrangements are determined. - Abstract: This paper presents the results of a numerical study conducted to investigate the discharging process of a latent heat thermal energy storage system assisted by finned heat pipes. A two-dimensional finite volume based numerical model along with enthalpy-porosity technique is employed to simulate the phase change of storage media during the discharging mode. The thermal energy storage system in this study consists of a square container, finned heat pipes, and potassium nitrate (KNO 3 ) as the phase change material. The charging process of the same thermal energy storage system was reported in an early paper by the authors. This paper reports the results of discharging process of the thermal energy storage system. The influences of heat pipe spacing, fin geometry and quantities as well as the effects of natural convection heat transfer on the thermal performance of the storage system were studied. The results indicate that the phase change material solidification process is hardly affected by the natural convection. Decreasing the heat pipe spacing results in faster discharging process and higher container base wall temperature. Increasing the fins length does not change the discharging time but yields higher base wall temperature. Using more fins also accelerates the discharging process and increases the container base wall temperature.

Direct and indirect toxicity of the fungicide pyraclostrobin to Hyalella azteca and effects on leaf processing under realistic daily temperature regimes

International Nuclear Information System (INIS)

Willming, Morgan M.; Maul, Jonathan D.

2016-01-01

Fungicides in aquatic environments can impact non-target bacterial and fungal communities and the invertebrate detritivores responsible for the decomposition of allochthonous organic matter. Additionally, in some aquatic systems daily water temperature fluctuations may influence these processes and alter contaminant toxicity, but such temperature fluctuations are rarely examined in conjunction with contaminants. In this study, the shredding amphipod Hyalella azteca was exposed to the fungicide pyraclostrobin in three experiments. Endpoints included mortality, organism growth, and leaf processing. One experiment was conducted at a constant temperature (23 °C), a fluctuating temperature regime (18–25 °C) based on field-collected data from the S. Llano River, Texas, or an adjusted fluctuating temperature regime (20–26 °C) based on possible climate change predictions. Pyraclostrobin significantly reduced leaf shredding and increased H. azteca mortality at concentrations of 40 μg/L or greater at a constant 23 °C and decreased leaf shredding at concentrations of 15 μg/L or greater in the fluctuating temperatures. There was a significant interaction between temperature treatment and pyraclostrobin concentration on H. azteca mortality, body length, and dry mass under direct aqueous exposure conditions. In an indirect exposure scenario in which only leaf material was exposed to pyraclostrobin, H. azteca did not preferentially feed on or avoid treated leaf disks compared to controls. This study describes the influence of realistic temperature variation on fungicide toxicity to shredding invertebrates, which is important for understanding how future alterations in daily temperature regimes due to climate change may influence the assessment of ecological risk of contaminants in aquatic ecosystems. - Highlights: • Pyraclostrobin was directly toxic to Hyalella azteca and reduced leaf processing. • Indirect exposure via leaf material did not change H

Exergy analysis of the biogas sorption-enhanced chemical looping reforming process integrated with a high-temperature proton exchange membrane fuel cell

International Nuclear Information System (INIS)

Kasemanand, Sarunyou; Im-orb, Karittha; Tippawan, Phanicha; Wiyaratn, Wisitsree; Arpornwichanop, Amornchai

2017-01-01

Highlights: • A biogas reforming and fuel cell integrated process is considered. • Energy and exergy analyses of the integrated process are performed. • Increasing the nickel oxide-to-biogas ratio decreases the exergy efficiency. • The exergy destruction of the fuel cell increases with increasing cell temperature. • The exergy efficiency of the process is improved when heat integration is applied. - Abstract: A biogas sorption-enhanced chemical looping reforming process integrated with a high-temperature proton exchange membrane fuel cell is analyzed. Modeling of such an integrated process is performed by using a flowsheet simulator (Aspen plus). The exergy analysis is performed to evaluate the energy utilization efficiency of each unit and that of the integrated process. The effect of steam and nickel oxide to biogas ratios on the exergetic performance of the stand-alone biogas sorption-enhanced chemical looping reforming process is investigated. The total exergy destruction increases as the steam or nickel oxide to biogas ratio increases. The main exergy destruction is found at the air reactor. For the high-temperature proton exchange membrane fuel cell, the main exergy destruction is found at the cathode. The total exergy destruction increases when cell temperature increases, whereas the inverse effect is found when the current density is considered as a key parameter. Regarding the exergy efficiency, the results show opposite trend to the exergy destruction. The heat integration analysis is performed to improve the exergetic performance. It is found that the integrated process including the heat integration system can improve the exergy destruction and exergy efficiency of 48% and 60%, respectively.

Mechanism and Influencing Factors of Iron Nuggets Forming in Rotary Hearth Furnace Process at Lower Temperature

Science.gov (United States)

Han, Hongliang; Duan, Dongping; Chen, Siming; Yuan, Peng

2015-10-01

In order to improve the efficiency of slag and iron separation, a new idea of "the separation of slag (solid state) and iron (molten state) in rotary hearth furnace process at lower temperature" is put forward. In this paper, the forming process of iron nuggets has been investigated. Based on those results, the forming mechanisms and influencing factors of iron nugget at low temperature are discussed experimentally using an electric resistance furnace simulating a rotary hearth furnace process. Results show that the reduction of iron ore, carburization of reduced iron, and the composition and quantity of slag are very important for producing iron nuggets at lower temperature. Reduction reaction of carbon-containing pellets is mainly at 1273 K and 1473 K (1000 °C and 1200 °C). When the temperature is above 1473 K (1200 °C), the metallization rate of carbon-containing pellets exceeds 93 pct, and the reduction reaction is substantially complete. Direct carburization is the main method for carburization of reduced iron. This reaction occurs above 1273 K (1000 °C), with carburization degree increasing greatly at 1473 K and 1573 K (1200 °C and 1300 °C) after particular holding times. Besides, to achieve the "slag (solid state) and iron (molten state) separation," the melting point of the slag phase should be increased. Slag (solid state) and iron (molten state) separation can be achieved below 1573 K (1300 °C), and when the holding time is 20 minutes, C/O is 0.7, basicity is less than 0.5 and a Na2CO3 level of 3 pct, the recovery rate of iron can reach 90 pct, with a proportion of iron nuggets more than 3.15 mm of nearly 90 pct. This study can provide theoretical and technical basis for iron nugget production.

Single Vs Mixed Organic Cation for Low Temperature Processed Perovskite Solar Cells

International Nuclear Information System (INIS)

Mahmud, Md Arafat; Elumalai, Naveen Kumar; Upama, Mushfika Baishakhi; Wang, Dian; Wright, Matthew; Chan, Kah Howe; Xu, Cheng; Haque, Faiazul; Uddin, Ashraf

2016-01-01

Highlights: • Low temperature processed ZnO based single & mixed organic cation perovskite device. • 37% higher PCE in mixed cation perovskite solar cells (PSCs) than single cation ones. • Mixed cation PSCs exhibit significantly reduced photocurrent hysteresis. • Mixed cation PSCs demonstrate three fold higher device stability than single cation PSCs. • Electronic properties are analyzed using Electrochemical Impedance Spectroscopy. - Abstract: The present work reports a comparative study between single and mixed organic cation based MAPbI 3 and MA 0.6 FA 0.4 PbI 3 perovskite devices fabricated in conjunction with low temperature processed (<150 °C) ZnO electron transport layers. MA 0.6 FA 0.4 PbI 3 perovskite devices demonstrate 37% higher power conversion efficiency compared to MAPbI 3 perovskite devices developed on the ZnO ETL. In addition, MA 0.6 FA 0.4 PbI 3 devices exhibit very low photocurrent hysteresis and they are three-fold more stable than conventional MAPbI 3 PSCs (perovskite solar cells). An in-depth analysis on the charge transport properties in both fresh and aged devices has been carried out using electrochemical impedance spectroscopy analysis to comprehend the enhanced device stability of the mixed perovskite devices developed on the ZnO ETL. The study also investigates into the interfacial charge transfer characteristics associated with the ZnO/mixed organic cation perovskite interface and concomitant influence on the inherent electronic properties.

Impact of the Low-Temperature Reactivity of Reillex(TM) HPQ on Actinide Processing

International Nuclear Information System (INIS)

Laurinat, J.E.

2001-01-01

Reactive System Screening Tool(TM) data and a computational model are used to predict the impact of pressurization on a typical process-scale ion exchange column due to gases generated by a low temperature exothermic reaction (LTE). The LTE results from a reaction between nitric acid and the ethylbenzene pendant groups of the Reillex(TM) HPQ resin. This reaction would occur if the resin bed were inadvertently heated above 70 degrees C

Rapid control of mold temperature during injection molding process

Energy Technology Data Exchange (ETDEWEB)

Liparoti, Sara; Titomanlio, Giuseppe [Department of Industrial Engineering, University of Salerno Via Giovanni Paolo II, 132, 84084 Fisciano (Italy); Hunag, Tsang Min; Cakmak, Mukerrem [Department of Polymer Engineering, The University of Akron, Akron, OH 44325 (United States); Sorrentino, Andrea [Institute for Polymers, Composite and Biomaterials (IPCB) - CNR, P. Enrico Fermi 1, 80055 Portici (Italy)

2015-05-22

The control of mold surface temperature is an important factor that determines surface morphology and its dimension in thickness direction. It can also affect the frozen molecular orientation and the mold surface replicability in injection molded products. In this work, thin thermally active films were used to quickly control the mold surface temperature. In particular, an active high electrical conductivity carbon black loaded polyimide composites sandwiched between two insulating thin polymeric layers was used to condition the mold surface. By controlling the heating time, it was possible to control precisely the temporal variation of the mold temperature surface during the entire cycle. The surface heating rate was about 40°C/s and upon contact with the polymer the surface temperature decreased back to 40°C within about 5 s; the overall cycle time increased only slightly. The effect on cross section sample morphology of samples of iPP were analyzed and discussed on the basis of the recorded temperature evolution.

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.

High-Pressure-High-Temperature Processing Reduces Maillard Reaction and Viscosity in Whey Protein-Sugar Solutions

NARCIS (Netherlands)

Avila Ruiz, Geraldine; Xi, Bingyan; Minor, Marcel; Sala, Guido; Boekel, van Tiny; Fogliano, Vincenzo; Stieger, Markus

2016-01-01

The aim of the study was to determine the influence of pressure in high-pressure-high-temperature (HPHT) processing on Maillard reactions and protein aggregation of whey protein-sugar solutions. Solutions of whey protein isolate containing either glucose or trehalose at pH 6, 7, and 9 were

Industrial Qualification Process for Optical Fibers Distributed Strain and Temperature Sensing in Nuclear Waste Repositories

Directory of Open Access Journals (Sweden)

S. Delepine-Lesoille

2012-01-01

Full Text Available Temperature and strain monitoring will be implemented in the envisioned French geological repository for high- and intermediate-level long-lived nuclear wastes. Raman and Brillouin scatterings in optical fibers are efficient industrial methods to provide distributed temperature and strain measurements. Gamma radiation and hydrogen release from nuclear wastes can however affect the measurements. An industrial qualification process is successfully proposed and implemented. Induced measurement uncertainties and their physical origins are quantified. The optical fiber composition influence is assessed. Based on radiation-hard fibers and carbon-primary coatings, we showed that the proposed system can provide accurate temperature and strain measurements up to 0.5 MGy and 100% hydrogen concentration in the atmosphere, over 200 m distance range. The selected system was successfully implemented in the Andra underground laboratory, in one-to-one scale mockup of future cells, into concrete liners. We demonstrated the efficiency of simultaneous Raman and Brillouin scattering measurements to provide both strain and temperature distributed measurements. We showed that 1.3 μm working wavelength is in favor of hazardous environment monitoring.

Application of Distributed Temperature Sensing for coupled mapping of sedimentation processes and spatio-temporal variability of groundwater discharge in soft-bedded streams

DEFF Research Database (Denmark)

Sebok, Eva; Duque, C; Engesgaard, Peter

2015-01-01

, maximum and mean streambed temperatures as well as the daily amplitude and standard deviation of temperatures. The identified potential high-discharge areas were mostly located near the channel banks, also showing temporal variability because of the scouring and redistribution of streambed sediments......The delineation of groundwater discharge areas based on Distributed Temperature Sensing (DTS) data of the streambed can be difficult in soft-bedded streams where sedimentation and scouring processes constantly change the position of the fibre optic cable relative to the streambed. Deposition...... variability in streambed temperatures between October 2011 and January 2012. Detailed monthly streambed elevation surveys were carried out to monitor the position of the fibre optic cable relative to the streambed and to quantify the effect of sedimentation processes on streambed temperatures. Based...

Microstructure, mechanical behavior and low temperature superplasticity of ECAP processed ZM21 Mg alloy

Energy Technology Data Exchange (ETDEWEB)

Mostaed, Ehsan, E-mail: ehsan.mostaed@polimi.it [Department of Mechanical Engineering, Politecnico di Milano, Milan (Italy); Fabrizi, Alberto [Department of Management and Engineering, Università di Padova, Stradella S. Nicola 3, 36100 Vicenza (Italy); Dellasega, David [Department of Energy, Politecnico di Milano, Milan (Italy); Bonollo, Franco [Department of Management and Engineering, Università di Padova, Stradella S. Nicola 3, 36100 Vicenza (Italy); Vedani, Maurizio [Department of Mechanical Engineering, Politecnico di Milano, Milan (Italy)

2015-07-25

Highlights: • We studied the effects of texture and grain size on ZM21 alloy mechanical behavior. • Yielding asymmetry was alleviated by either texture weakening or grain refining. • At room temperature and 150 °C fracture elongation was strongly texture dependent. • Superplasticity at 200 °C was influenced by grain size, appearing only in UFG alloy. - Abstract: In this study, ultra-fine grained ZM21 Mg alloy was obtained through two-stage equal channel angular pressing process (ECAP) at temperatures of 200 and 150 °C. For each stage four passes were used. Plastic behavior, mechanical asymmetry and low temperature superplasticity of ultra-fine grained ZM21 alloy were investigated as a function of processing condition with particular attention to microstructural and texture evolution. Microstructural observations showed that after the first stage of ECAP an equiaxed ultra-fine grain (UFG) structure with average size of 700 nm was obtained. Additional stage did not cause any further grain refinement. However, Electron Backscattered Diffraction analysis showed that the original extrusion fiber texture evolved into a new one featuring a favorable alignment of the basal planes along ECAP shear planes. Such a preferential alignment provided a considerably higher Schmid factor value of 0.32, resulting in a remarkable loss in tensile yield stress, from 212 to 110 MPa and an improvement of the tensile fracture elongation, from 24% to 40%. Tensile and compression tests at room temperature revealed that yielding asymmetry could be alleviated by either weakening of basal plane fiber texture or by grain refinement. Tensile tests at 150 °C showed that texture supplies a significant contribution to plastic flow and elongation, making dislocation slip the dominant mechanism for deformation, while grain boundary sliding was not actively operated at this temperature. However, at 200 °C the effect of texture on fracture elongation of UFG alloys was subtle and the impact

The role of inelastic processes in the temperature dependence of hall induced resistance oscillations

International Nuclear Information System (INIS)

Kunold, Alejandro; Torres, Manuel

2013-01-01

We develop a model of magnetoresistance oscillations induced by the Hall field in order to study the temperature dependence observed in recent experiments in two dimensional electron systems. The model is based on the solution of the von Neumann equation incorporating the exact dynamics of two-dimensional damped electrons in the presence of arbitrarily strong magnetic and dc electric fields, while the effects of randomly distributed neutral and charged impurities are perturbatively added. Both the effects of elastic impurity scattering as well as those related to inelastic processes play an important role. The theoretical predictions correctly reproduce the experimentally observed oscillations amplitude, provided that the quantum inelastic scattering rate obeys a T 2 temperature dependence, consistent with electron–electron interaction effects

Effects of carbon nanotube content and annealing temperature on the hardness of CNT reinforced aluminum nanocomposites processed by the high pressure torsion technique

Energy Technology Data Exchange (ETDEWEB)

Phuong, Doan Dinh, E-mail: phuongdd@ims.vast.ac.vn [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay Distr., Hanoi (Viet Nam); Trinh, Pham Van; An, Nguyen Van; Luan, Nguyen Van; Minh, Phan Ngoc [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Str., Cau Giay Distr., Hanoi (Viet Nam); Khisamov, Rinat Kh.; Nazarov, Konstantin S.; Zubairov, Linar R.; Mulyukov, Radik R.; Nazarov, Ayrat A. [Institute for Metals Superplasticity Problems, Russian Academy of Sciences 39, Stepan Khalturin Str., Ufa 450001 (Russian Federation)

2014-11-15

Highlights: • CNT/Al nanocomposites were consolidated by HIP and subsequently processed by the high pressure torsion technique. • High pressure torsion processing was unable to break apart or disperse the CNT agglomerates persisted in powder preparation. • HPT-processed CNT/Al nanocomposites exhibited secondary hardening during annealing at temperatures below 150 °C. - Abstract: In this paper, the microstructure and hardness of CNT reinforced aluminium (CNT/Al) nanocomposites prepared by the advanced powder metallurgy method and subsequently processed by the high pressure torsion (HPT) technique are studied. The effects of CNT content and annealing temperature on the hardness of the nanocomposites are investigated. The results show that annealing materials at temperatures below 150 °C leads to secondary hardening, while annealing at higher temperatures soften the nanocomposites. HPT-processed CNT/Al nanocomposites with 1.5 wt.% of CNTs are shown to have the highest hardness in comparison with other composites containing CNTs from 0 up to 2 wt.%. Microstructures, CNT distribution and the phase composition of CNT/Al nanocomposites are investigated by transmission and scanning electron microscopy and X-ray diffraction techniques.

Low temperature processed InGaZnO thin film transistor using the combination of hydrogen irradiation and annealing

Energy Technology Data Exchange (ETDEWEB)

Park, Hyun-Woo; Choi, Min-Jun; Jo, Yongcheol; Chung, Kwun-Bum, E-mail: kbchung@dongguk.edu

2014-12-01

Highlights: • We studied the low temperature process of InGaZnO oxide thin film transistor. • Hydorgen irradiation was used for low temperature process below 150 °C. • Using hydrogen irradiation, field effect mobility of IGZO TFT was enhanced to ∼5 cm{sup 2} /Vs. • We examined the origin of improvement of device performance via electronic structure. - Abstract: Device performance of radio frequency (RF) sputtered InGaZnO (IGZO) thin film transistors (TFTs) were improved using combination post-treatment with hydrogen irradiation and low temperature annealing at 150 °C. Under the combination treatment, IGZO TFTs were significantly enhanced without changing physical structure and chemical composition. On the other hand, the electronic structure represents a dramatically modification of the chemical bonding states, band edge states below the conduction band, and band alignment. Compared to the hydrogen irradiation or low temperature annealing, the combination treatment induces the increase of oxygen deficient chemical bonding states, the shallow band edge state below the conduction band, and the smaller energy difference of conduction band offset, which can generate the increase in charge carrier and enhance the device performance.

Effect of temperature downshifts on a bench-scale hybrid A/O system: Process performance and microbial community dynamics.

Science.gov (United States)

Zhou, Hexi; Li, Xiangkun; Chu, Zhaorui; Zhang, Jie

2016-06-01

Effect of temperature downshifts on process performance and bacterial community dynamics was investigated in a bench-scale hybrid A/O system treating real domestic wastewater. Results showed that the average COD removal in this system reached 90.5%, 89.1% and 90.3% for Run 1 (25 °C), Run 2 (15 °C) and Run 3 (10 °C), respectively, and variations in temperature barely affected the effluent COD concentration. The average removal efficiencies of NH4(+)-N were 98.4%, 97.8%, 95.7%, and that of TN were 77.1%, 61.8%, 72% at 25 °C, 15 °C and 10 °C, respectively. Although the hybrid system was subjected to low temperature, this process effectively removed NH4(+)-N and TN even at 10 °C with the average effluent concentrations of 2.4 mg/L and 14.3 mg/L, respectively. Results from high-throughput sequencing analysis revealed that when the operation temperature decreased from 25 °C to 10 °C, the richness and diversity indexes of the system decreased in the sludge samples, while underwent an increase in the biofilm samples. Furthermore, the major heterotrophic bacteria consisted of Lewinella, Lutimonas, Chitinophaga and Fluviicola at 10 °C, which could be central to effective COD removal at low temperature. Additionally, Azospira, one denitrifying-related genus increased from 0.4% to 4.45% in the biofilm samples, with a stable TN removal in response to temperature downshifts. Nitrosomonas and Nitrospira increased significantly in the biofilm samples, implying that the attached biofilm contributed to more nitrification at low temperature. Copyright © 2016 Elsevier Ltd. All rights reserved.

Full Scale Field Trial of the Low Temperature Mercury Capture Process

Energy Technology Data Exchange (ETDEWEB)

Locke, James [CONSOL Energy Inc., South Park, PA (United States); Winschel, Richard [CONSOL Energy Inc., South Park, PA (United States)

2012-05-21

CONSOL Energy Inc., with partial funding from the Department of Energy (DOE) National Energy Technology Laboratory, designed a full-scale installation for a field trial of the Low-Temperature Mercury Control (LTMC) process, which has the ability to reduce mercury emissions from coal-fired power plants by over 90 percent, by cooling flue gas temperatures to approximately 230°F and absorbing the mercury on the native carbon in the fly ash, as was recently demonstrated by CONSOL R&D on a slip-stream pilot plant at the Allegheny Energy Mitchell Station with partial support by DOE. LTMC has the potential to remove over 90 percent of the flue gas mercury at a cost at least an order of magnitude lower (on a $/lb mercury removed basis) than activated carbon injection. The technology is suitable for retrofitting to existing and new plants, and, although it is best suited to bituminous coal-fired plants, it may have some applicability to the full range of coal types. Installation plans were altered and moved from the original project host site, PPL Martins Creek plant, to a second host site at Allegheny Energy's R. Paul Smith plant, before installation actually occurred at the Jamestown (New York) Board of Public Utilities (BPU) Samuel A. Carlson (Carlson) Municipal Generating Station Unit 12, where the LTMC system was operated on a limited basis. At Carlson, over 60% mercury removal was demonstrated by cooling the flue gas to 220-230°F at the ESP inlet via humidification. The host unit ESP operation was unaffected by the humidification and performed satisfactorily at low temperature conditions.

High-temperature deformation and processing maps of Zr-4 metal matrix with dispersed coated surrogate nuclear fuel particles

Science.gov (United States)

Chen, Jing; Liu, Huiqun; Zhang, Ruiqian; Li, Gang; Yi, Danqing; Lin, Gaoyong; Guo, Zhen; Liu, Shaoqiang

2018-06-01

High-temperature compression deformation of a Zr-4 metal matrix with dispersed coated surrogate nuclear fuel particles was investigated at 750 °C-950 °C with a strain rate of 0.01-1.0 s-1 and height reduction of 20%. Scanning electron microscopy was utilized to investigate the influence of the deformation conditions on the microstructure of the composite and damage to the coated surrogate fuel particles. The results indicated that the flow stress of the composite increased with increasing strain rate and decreasing temperature. The true stress-strain curves showed obvious serrated oscillation characteristics. There were stable deformation ranges at the initial deformation stage with low true strain at strain rate 0.01 s-1 for all measured temperatures. Additionally, the coating on the surface of the surrogate nuclear fuel particles was damaged when the Zr-4 matrix was deformed at conditions of high strain rate and low temperature. The deformation stability was obtained from the processing maps and microstructural characterization. The high-temperature deformation activation energy was 354.22, 407.68, and 433.81 kJ/mol at true strains of 0.02, 0.08, and 0.15, respectively. The optimum deformation parameters for the composite were 900-950 °C and 0.01 s-1. These results are expected to provide guidance for subsequent determination of possible hot working processes for this composite.

Methods for Prediction of Steel Temperature Curve in the Whole Process of a Localized Fire in Large Spaces

Directory of Open Access Journals (Sweden)

Zhang Guowei

2014-01-01

Full Text Available Based on a full-scale bookcase fire experiment, a fire development model is proposed for the whole process of localized fires in large-space buildings. We found that for localized fires in large-space buildings full of wooden combustible materials the fire growing phases can be simplified into a t2 fire with a 0.0346 kW/s2 fire growth coefficient. FDS technology is applied to study the smoke temperature curve for a 2 MW to 25 MW fire occurring within a large space with a height of 6 m to 12 m and a building area of 1 500 m2 to 10 000 m2 based on the proposed fire development model. Through the analysis of smoke temperature in various fire scenarios, a new approach is proposed to predict the smoke temperature curve. Meanwhile, a modified model of steel temperature development in localized fire is built. In the modified model, the localized fire source is treated as a point fire source to evaluate the flame net heat flux to steel. The steel temperature curve in the whole process of a localized fire could be accurately predicted by the above findings. These conclusions obtained in this paper could provide valuable reference to fire simulation, hazard assessment, and fire protection design.

Comparison of room temperature and cyrogenic sample processing in the analysis of chemical contaminants in foods

Science.gov (United States)

In this study, analytical results were compared when using different approaches to bulk food sample comminution, consisting of a vertical chopper (Blixer) at room temperature and at dry ice cryogenic conditions, followed by further subsample processing (20 g) using liquid nitrogen cryogenic conditio...

Temperature metrology

Science.gov (United States)

Fischer, J.; Fellmuth, B.

2005-05-01

The majority of the processes used by the manufacturing industry depend upon the accurate measurement and control of temperature. Thermal metrology is also a key factor affecting the efficiency and environmental impact of many high-energy industrial processes, the development of innovative products and the health and safety of the general population. Applications range from the processing, storage and shipment of perishable foodstuffs and biological materials to the development of more efficient and less environmentally polluting combustion processes for steel-making. Accurate measurement and control of temperature is, for instance, also important in areas such as the characterization of new materials used in the automotive, aerospace and semiconductor industries. This paper reviews the current status of temperature metrology. It starts with the determination of thermodynamic temperatures required on principle because temperature is an intensive quantity. Methods to determine thermodynamic temperatures are reviewed in detail to introduce the underlying physical basis. As these methods cannot usually be applied for practical measurements the need for a practical temperature scale for day-to-day work is motivated. The International Temperature Scale of 1990 and the Provisional Low Temperature Scale PLTS-2000 are described as important parts of the International System of Units to support science and technology. Its main importance becomes obvious in connection with industrial development and international markets. Every country is strongly interested in unique measures, in order to guarantee quality, reproducibility and functionability of products. The eventual realization of an international system, however, is only possible within the well-functioning organization of metrological laboratories. In developed countries the government established scientific institutes have certain metrological duties, as, for instance, the maintenance and dissemination of national

Temperature metrology

International Nuclear Information System (INIS)

Fischer, J; Fellmuth, B

2005-01-01

The majority of the processes used by the manufacturing industry depend upon the accurate measurement and control of temperature. Thermal metrology is also a key factor affecting the efficiency and environmental impact of many high-energy industrial processes, the development of innovative products and the health and safety of the general population. Applications range from the processing, storage and shipment of perishable foodstuffs and biological materials to the development of more efficient and less environmentally polluting combustion processes for steel-making. Accurate measurement and control of temperature is, for instance, also important in areas such as the characterization of new materials used in the automotive, aerospace and semiconductor industries. This paper reviews the current status of temperature metrology. It starts with the determination of thermodynamic temperatures required on principle because temperature is an intensive quantity. Methods to determine thermodynamic temperatures are reviewed in detail to introduce the underlying physical basis. As these methods cannot usually be applied for practical measurements the need for a practical temperature scale for day-to-day work is motivated. The International Temperature Scale of 1990 and the Provisional Low Temperature Scale PLTS-2000 are described as important parts of the International System of Units to support science and technology. Its main importance becomes obvious in connection with industrial development and international markets. Every country is strongly interested in unique measures, in order to guarantee quality, reproducibility and functionability of products. The eventual realization of an international system, however, is only possible within the well-functioning organization of metrological laboratories. In developed countries the government established scientific institutes have certain metrological duties, as, for instance, the maintenance and dissemination of national

Numerical simulation of temperature distribution using finite difference equations and estimation of the grain size during friction stir processing

International Nuclear Information System (INIS)

Arora, H.S.; Singh, H.; Dhindaw, B.K.

2012-01-01

Highlights: ► Magnesium alloy AE42 was friction stir processed under different cooling conditions. ► Heat flow model was developed using finite difference heat equations. ► Generalized MATLAB code was developed for solving heat flow model. ► Regression equation for estimation of grain size was developed. - Abstract: The present investigation is aimed at developing a heat flow model to simulate temperature history during friction stir processing (FSP). A new approach of developing implicit form of finite difference heat equations solved using MATLAB code was used. A magnesium based alloy AE42 was friction stir processed (FSPed) at different FSP parameters and cooling conditions. Temperature history was continuously recorded in the nugget zone during FSP using data acquisition system and k type thermocouples. The developed code was validated at different FSP parameters and cooling conditions during FSP experimentation. The temperature history at different locations in the nugget zone at different instants of time was further utilized for the estimation of grain growth rate and final average grain size of the FSPed specimen. A regression equation relating the final grain size, maximum temperature during FSP and the cooling rate was developed. The metallurgical characterization was done using optical microscopy, SEM, and FIB-SIM analysis. The simulated temperature profiles and final average grain size were found to be in good agreement with the experimental results. The presence of fine precipitate particles generated in situ in the investigated magnesium alloy also contributed in the evolution of fine grain structure through Zener pining effect at the grain boundaries.

Evaluation of Integrated Time-Temperature Effect in Pyrolysis Process of Historically Contaminated Soils with Cadmium (Cd and Lead (Pb

Directory of Open Access Journals (Sweden)

Bulmău C

2013-04-01

Full Text Available It is already known that heavy metals pollution causes important concern to human and ecosystem health. Heavy metals in soils at the European level represents 37.3% between main contaminates affecting soils (EEA, 2007. This paper illustrates results obtained in the framework of laboratory experiments concerning the evaluation of integrated time-temperature effect in pyrolysis process applied to contaminated soil by two different ways: it is about heavy metals historically contaminated soil from one of the most polluted areas within Romania, and artificially contaminated with PCB-containing transformer oil. In particular, the authors focused on a recent evaluation of pyrolysis efficiency on removing lead (Pb and cadmium (Cd from the contaminated soil. The experimental study evaluated two important parameters related to the studied remediation methodology: thermal process temperature and the retention time in reactor of the contaminated soils. The remediation treatments were performed in a rotary kiln reactor, taking into account three process temperatures (400°C, 600°C and 800°C and two retention times: 30 min. and 60 min. Completed analyses have focused on pyrolysis solids and gas products. Consequently, both ash and gas obtained after pyrolysis process were subjected to chemical analyses.

Microstructural optimization of high temperature SiC/SiC composites by nite process

International Nuclear Information System (INIS)

Shimoda, K.; Park, J.S.; Hinoki, T.; Kohyama, A.

2007-01-01

Full text of publication follows: SiC/SiC composites are one of the promising structural materials for future fusion reactor because of the excellent potentiality in thermal and mechanical properties under very severe environment including high temperature and high energy neutron bombardment. For fusion-grade SiC/SiC composites, high-crystallinity and near-stoichiometric characteristic are required to keep excellent stability against neutron irradiation. The realization of the reactor will be strongly depend on optimization of SiC/SiC composites microstructure, particularly in regard to the materials and processes used for the fiber, interphase and matrix constituents. One of the important accomplishments is the new process, called nano-particle infiltration and transient eutectic phase (NITE) process developed in our group. The microstructure of NITE-SiC/SiC composites, such as fiber volume fraction, porosity and type of pores, can be controlled precisely by the selection of sintering temperature/applied stress history. The objective of this study is to investigate thermal stability and mechanical properties of NITE-SiC/SiC composites at high-temperature. Two kinds of highly-densified SiC/SiC composites with the difference of fiber volume fraction were prepared, and were subjected to exposure tests from 1000 deg. C to 1500 deg. C in an argon-oxygen gas mixture with an oxygen partial pressure of 0.1 Pa. The thermal stability of the composites was characterized through mass change and TEM/SEM observation. The in-situ tensile tests at 1300 deg. C and 1500 deg. C were carried out in the same atmosphere. Most of SiC/SiC composites, even for the advanced CVI-SiC/SiC composites with multi-layered SiC/C inter-phases, underwent reduction in the maximum strength by about 20% at 1300 deg. C. In particular, this reduction was attributed to a slight burnout of the carbon interphase due to oxygen impurities in test atmosphere. However, there was no significant degradation for

Microstructural optimization of high temperature SiC/SiC composites by nite process

Energy Technology Data Exchange (ETDEWEB)

Shimoda, K. [Kyoto Univ., Graduate School of Energy Science (Japan); Park, J.S. [Kyoto Univ., Institute of Advanced Energy (Japan); Hinoki, T.; Kohyama, A. [Kyoto Univ., lnstitute of Advanced Energy, Gokasho, Uji (Japan)

2007-07-01

Full text of publication follows: SiC/SiC composites are one of the promising structural materials for future fusion reactor because of the excellent potentiality in thermal and mechanical properties under very severe environment including high temperature and high energy neutron bombardment. For fusion-grade SiC/SiC composites, high-crystallinity and near-stoichiometric characteristic are required to keep excellent stability against neutron irradiation. The realization of the reactor will be strongly depend on optimization of SiC/SiC composites microstructure, particularly in regard to the materials and processes used for the fiber, interphase and matrix constituents. One of the important accomplishments is the new process, called nano-particle infiltration and transient eutectic phase (NITE) process developed in our group. The microstructure of NITE-SiC/SiC composites, such as fiber volume fraction, porosity and type of pores, can be controlled precisely by the selection of sintering temperature/applied stress history. The objective of this study is to investigate thermal stability and mechanical properties of NITE-SiC/SiC composites at high-temperature. Two kinds of highly-densified SiC/SiC composites with the difference of fiber volume fraction were prepared, and were subjected to exposure tests from 1000 deg. C to 1500 deg. C in an argon-oxygen gas mixture with an oxygen partial pressure of 0.1 Pa. The thermal stability of the composites was characterized through mass change and TEM/SEM observation. The in-situ tensile tests at 1300 deg. C and 1500 deg. C were carried out in the same atmosphere. Most of SiC/SiC composites, even for the advanced CVI-SiC/SiC composites with multi-layered SiC/C inter-phases, underwent reduction in the maximum strength by about 20% at 1300 deg. C. In particular, this reduction was attributed to a slight burnout of the carbon interphase due to oxygen impurities in test atmosphere. However, there was no significant degradation for

Processing and characterization of aluminium alloys or composites exhibiting low-temperature or high-rate superplasticity

International Nuclear Information System (INIS)

Huang, J. C.

1997-01-01

Wide applications of superplastic forming still face several problems, one is the high temperature that promotes grain growth, another is the low forming rate that makes economically inefficient. The current study is intended to develop a series of fabrication and thermomechanical processing, so as to result in materials possessing either low temperature superplasticity (LTSP) or high rate superplasticity (HRSP). The former has been achieved in the cast Al alloys, while the latter was accomplished in powder-metallurgy aluminium matrix composites. The aluminium alloys, after special thermomechanical processes, exhibited LTSP from 300 to 450 degree C with elongations varying from 300 to 700 %. The LTSP sheets after 700 % elongation at 350 degree C still possessed fine grains 3.7 μm size and narrow surface solute depletion zones 11 μm in with, resulting in a post-SP T6 strength of 500 MPa, significantly higher than that of the HTSP superplasticity alloys tested at 525 degree C or above. Meanwhile, it was found that LTSP materials may be transferred into HTSP materials simply by adding a preloading at 300-400 degree C for a small amount of work. As for the endeavor in making HRSP materials, 2024Al/SiC, 6061Al/SiC and Al/Al 3 Ti systems processed by powder metallurgy or mechanical alloying methods are under investigation. The average sizes of the reinforcing SiC or A13Ti particles, as well as the grain size are all around 1 μm. The aluminium composites have exhibited HRSP at 525-620 degree C and 10 -2 -10 -1 s -l , with elongations varying from 150 to 350 %. This ultimate goal is to produce an alloy or composite exhibiting low temperature and high strain rate superplasticity (LT and HRSP). (author)

Low-temperature processed SnO{sub 2} compact layer for efficient mesostructure perovskite solar cells

Energy Technology Data Exchange (ETDEWEB)

Duan, Jinxia; Xiong, Qiu; Feng, Bingjie; Xu, Yang; Zhang, Jun; Wang, Hao, E-mail: nanoguy@126.com

2017-01-01

Highlights: • Low-temperature processed 70 nm cl-SnO{sub 2} device exhibits maximum PCE. • Champion PSC after SnCl{sub 4} treatment acquires PCE of 15.07%. • Cl-SnO{sub 2} PSC via SnCl{sub 4} treatment exhibits superior stability to cl-TiO{sub 2} based PSC. - Abstract: SnO{sub 2} nanoparticle film has been synthesized via low- temperature (∼180 °C) solution-processing and proposed as compact layer in mesostructure perovskite-type solar cell (PSC). Low-temperature processed SnO{sub 2} compact layer (cl-SnO{sub 2}) brings perfect crystal-lattice and band-gap matching between electron selective layer and FTO substrate and close interface-contact between cl-SnO{sub 2} and mesoporous TiO{sub 2} layer (mp-TiO{sub 2}), which contributes to suppressing carrier recombination and optimizing device performance. In varied thickness cells, 70 nm cl-SnO{sub 2} device exhibits maximum power conversion efficiency (PCE). In order to further restrain photoelectron recombination and improve the photovoltaic performance, the surface modification of cl-SnO{sub 2} by SnCl{sub 4} aqueous solution has been carried out. The recombination behavior in the cell interior is greatly retarded via SnCl{sub 4} treatment and champion PSC after SnCl{sub 4} treatment has acquire PCE of 15.07%, which is higher than PCE of cl-TiO{sub 2} based PSC fabricated with same mp-TiO{sub 2} and perovskite procedures (13.3%). The stability of cl-SnO{sub 2} PSC via SnCl{sub 4} treatment has also been measured and its PCE reduces to 13.0% after 2 weeks in air.

Processing of fine grained AISI 304L austenitic stainless steel by cold rolling and high-temperature short-term annealing

Science.gov (United States)

Naghizadeh, Meysam; Mirzadeh, Hamed

2018-05-01

An advanced thermomechanical process based on the formation and reversion of deformation-induced martensite was used to refine the grain size and enhance the hardness of an AISI 304L austenitic stainless steel. Both low and high reversion annealing temperatures and also the repetition of the whole thermomechanical cycle were considered. While a microstructure with average austenite grain size of a few micrometers was achieved based on cold rolling and high-temperature short-term annealing, an extreme grain refinement up to submicrometer regime was obtained by cold rolling followed by low-temperature long-term annealing. However, the required annealing time was found to be much longer, which negates its appropriateness for industrial production. While a magnificent grain refinement was achieved by one pass of the high-temperature thermomechanical process, the reduction in grain size was negligible by the repetition of the whole cycle. It was found that the hardness of the thermomechanically processed material is much higher than that of the as-received material. The results of the present work were shown to be compatible with the general trend of grain size dependence of hardness for AISI 304L stainless steel based on the Hall-Petch relationship. The results were also discussed based on the X-ray evaluation of dislocation density by modified Williamson-Hall plots.

Development and Characterization of Improved NiTiPd High-Temperature Shape-Memory Alloys by Solid-Solution Strengthening and Thermomechanical Processing

Science.gov (United States)

Bigelow, Glen; Noebe, Ronald; Padula, Santo, II; Garg, Anita; Olson, David

2006-01-01

The need for compact, solid-state actuation systems for use in the aerospace, automotive, and other transportation industries is currently motivating research in high-temperature shape-memory alloys (HTSMA) with transformation temperatures greater than 100 C. One of the basic high-temperature alloys investigated to fill this need is Ni(19.5)Ti(50.5)Pd30. Initial testing has indicated that this alloy, while having acceptable work characteristics, suffers from significant permanent deformation (or ratcheting) during thermal cycling under load. In an effort to overcome this deficiency, various solid-solution alloying and thermomechanical processing schemes were investigated. Solid-solution strengthening was achieved by substituting 5at% gold or platinum for palladium in Ni(19.5)Ti(50.5)Pd30, the so-called baseline alloy, to strengthen the martensite and austenite phases against slip processes and improve thermomechanical behavior. Tensile properties, work behavior, and dimensional stability during repeated thermal cycling under load for the ternary and quaternary alloys were compared. The relative difference in yield strength between the martensite and austenite phases and the dimensional stability of the alloy were improved by the quaternary additions, while work output was only minimally impacted. The three alloys were also thermomechanically processed by cycling repeatedly through the transformation range under a constant stress. This so-called training process dramatically improved the dimensional stability in these samples and also recovered the slight decrease in work output caused by quaternary alloying. An added benefit of the solid-solution strengthening was maintenance of enhanced dimensional stability of the trained material to higher temperatures compared to the baseline alloy, providing a greater measure of over-temperature capability.

Applicability test of glass lining material for high-temperature acidic solutions of sulfuric acid in thermochemical water-splitting IS process

International Nuclear Information System (INIS)

Iwatsuki, Jin; Tanaka, Nobuyuki; Terada, Atsuhiko; Onuki, Kaoru; Watanabe, Yutaka

2010-01-01

A key issue for realizing the thermochemical IS process for hydrogen production is the selection of materials for working with high-temperature acidic solutions of sulfuric acid and hydriodic acid. Glass lining material is a promising candidate, which is composed of steel having good strength and glass having good corrosion resistance. Since the applicability of glass lining material depends strongly on the service condition, corrosion tests using glass used in glass lining material and heat cycle tests using glass lining piping were carried out to examine the possibility of using the glass lining material with high-temperature acidic solutions of sulfuric acid. It was confirmed that the glass lining materials exhibited sufficient corrosion resistance and heat resistance in high-temperature sulfuric acid of the IS process. (author)

High-performance zno transistors processed via an aqueous carbon-free metal oxide precursor route at temperatures between 80-180 °c

KAUST Repository

Lin, Yenhung

2013-06-25

An aqueous and carbon-free metal-oxide precursor route is used in combination with a UV irradiation-assisted low-temperature conversion method to fabricate low-voltage ZnO transistors with electron mobilities exceeding 10 cm2/Vs at temperatures <180°C. Because of its low temperature requirements the method allows processing of high-performance transistors onto temperature sensitive substrates such as plastic. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The microstructure, texture, and room temperature mechanical properties of friction stir processed Mg-Y-Nd alloy

Energy Technology Data Exchange (ETDEWEB)

Jamili, A.M. [The Complex Laboratory of Hot Deformation and Thermomechanical Processing of High Performance Engineering Materials, School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Zarei-Hanzaki, A., E-mail: zareih@ut.ac.ir [The Complex Laboratory of Hot Deformation and Thermomechanical Processing of High Performance Engineering Materials, School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Abedi, H.R. [The Complex Laboratory of Hot Deformation and Thermomechanical Processing of High Performance Engineering Materials, School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Minárik, P. [Department of Physics of Materials, Charles University, Prague (Czech Republic); Soltani, R. [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)

2017-04-06

The effects of severe plastic straining, in the course of single and multi-pass friction stir processing (FSP), on the microstructure, texture and mechanical properties of an as-extruded WE43 Magnesium alloy are addressed in the present study. The latter was explored by applying a set of 1 and 3-passes FSP trials on the experimental material. The evolved microstructures were characterized through electron backscatter diffraction analyses. The results indicated an extraordinary reduction in grain size in addition to remarkable decrease in second phase volume fraction in the light of preferred strain rate and temperature conditions. The micro-textures of processed specimens were evaluated through plotting the Schmid factor maps and its distribution. The corresponding results showed that the basal planes poles intensity was increased after each step of FSP trials. The prismatic texture analyses also indicated the randomized and weakened distributed planes. The room temperature mechanical properties of the processed materials were also measured using tensile testing technique. The optimization of the strength and ductility values was attributed to the grain refinement, dynamic dissolution of the second phase and the texture strengthening at proper thermomechanical conditions.

The electrochemical reduction processes of solid compounds in high temperature molten salts.

Science.gov (United States)

Xiao, Wei; Wang, Dihua

2014-05-21

Solid electrode processes fall in the central focus of electrochemistry due to their broad-based applications in electrochemical energy storage/conversion devices, sensors and electrochemical preparation. The electrolytic production of metals, alloys, semiconductors and oxides via the electrochemical reduction of solid compounds (especially solid oxides) in high temperature molten salts has been well demonstrated to be an effective and environmentally friendly process for refractory metal extraction, functional materials preparation as well as spent fuel reprocessing. The (electro)chemical reduction of solid compounds under cathodic polarizations generally accompanies a variety of changes at the cathode/melt electrochemical interface which result in diverse electrolytic products with different compositions, morphologies and microstructures. This report summarizes various (electro)chemical reactions taking place at the compound cathode/melt interface during the electrochemical reduction of solid compounds in molten salts, which mainly include: (1) the direct electro-deoxidation of solid oxides; (2) the deposition of the active metal together with the electrochemical reduction of solid oxides; (3) the electro-inclusion of cations from molten salts; (4) the dissolution-electrodeposition process, and (5) the electron hopping process and carbon deposition with the utilization of carbon-based anodes. The implications of the forenamed cathodic reactions on the energy efficiency, chemical compositions and microstructures of the electrolytic products are also discussed. We hope that a comprehensive understanding of the cathodic processes during the electrochemical reduction of solid compounds in molten salts could form a basis for developing a clean, energy efficient and affordable production process for advanced/engineering materials.

Fabrication and Microstructure of Hydroxyapatite Coatings on Zirconia by Room Temperature Spray Process.

Science.gov (United States)

Seo, Dong Seok; Chae, Hak Cheol; Lee, Jong Kook

2015-08-01

Hydroxyapatite coatings were fabricated on zirconia substrates by a room temperature spray process and were investigated with regards to their microstructure, composition and dissolution in water. An initial hydroxyapatite powder was prepared by heat treatment of bovine-bone derived powder at 1100 °C for 2 h, while dense zirconia substrates were fabricated by pressing 3Y-TZP powder and sintering it at 1350 °C for 2 h. Room temperature spray coating was performed using a slit nozzle in a low pressure-chamber with a controlled coating time. The phase composition of the resultant hydroxyapatite coatings was similar to that of the starting powder, however, the grain size of the hydroxyapatite particles was reduced to about 100 nm due to their formation by particle impaction and fracture. All areas of the coating had a similar morphology, consisting of reticulated structure with a high surface roughness. The hydroxyapatite coating layer exhibited biostability in a stimulated body fluid, with no severe dissolution being observed during in vitro experimentation.

Stacking Defects in Synthetic and Meteoritic Hibonites: Implications for High-Temperature Processes in the Solar Nebula

Science.gov (United States)

Han, J.; Keller, L. P.; Brearley, A. J.; Danielson, L. R.

2016-01-01

Hibonite (CaAl12O19) is a primary, highly refractory phase occurring in many Ca-Al-rich inclusions (CAIs) from different chondrite groups, except CI chondrites. Hibonite is predicted to be one of the earliest minerals to condense during cooling of the solar nebula at higher temperatures than any other major CAI mineral. Therefore, hibonite has great potential to reveal the processes and conditions of the very early, high-temperature stages of the solar nebular evolution. Previous microstructural studies of hibonite in CAIs and their Wark-Lovering (WL) rims showed the presence of numerous stacking defects in hibonite. These defects are interpreted as the modification of the stacking sequences of spinel and Ca-containing blocks within the ideal hexagonal hibonite structure, as shown by experimental studies of reaction-sintered ceramic CaO-Al2O3 compounds. We performed preliminary experiments in the CaO-Al2O3-MgO system to understand the formation processes and conditions of defect-structured hibonite found in meteorites.

Thermomechanical process optimization of U-10 wt% Mo – Part 1: high-temperature compressive properties and microstructure

Energy Technology Data Exchange (ETDEWEB)

Joshi, Vineet V., E-mail: vineet.joshi@pnnl.gov [Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Nyberg, Eric A.; Lavender, Curt A.; Paxton, Dean [Pacific Northwest National Laboratory, Richland, WA 99354 (United States); Garmestani, Hamid [Georgia Institute of Technology, Atlanta, GA 30332 (United States); Burkes, Douglas E. [Pacific Northwest National Laboratory, Richland, WA 99354 (United States)

2015-10-15

Nuclear power research facilities require alternatives to existing highly enriched uranium alloy fuel. One option for a high density metal fuel is uranium alloyed with 10 wt% molybdenum (U–10Mo). Fuel fabrication process development requires specific mechanical property data that, to date has been unavailable. In this work, as-cast samples were compression tested at three strain rates over a temperature range of 400–800 °C to provide data for hot rolling and extrusion modeling. The results indicate that with increasing test temperature the U–10Mo flow stress decreases and becomes more sensitive to strain rate. In addition, above the eutectoid transformation temperature, the drop in material flow stress is prominent and shows a strain-softening behavior, especially at lower strain rates. Room temperature X-ray diffraction and scanning electron microscopy combined with energy dispersive spectroscopy analysis of the as-cast and compression tested samples were conducted. The analysis revealed that the as-cast samples and the samples tested below the eutectoid transformation temperature were predominantly γ phase with varying concentration of molybdenum, whereas the ones tested above the eutectoid transformation temperature underwent significant homogenization.

Novel immobilization process of a thermophilic catalase: efficient purification by heat treatment and subsequent immobilization at high temperature.

Science.gov (United States)

Xu, Juan; Luo, Hui; López, Claudia; Xiao, Jing; Chang, Yanhong

2015-10-01

The main goal of the present work is to investigate a novel process of purification and immobilization of a thermophilic catalase at high temperatures. The catalase, originated from Bacillus sp., was overexpressed in a recombinant Escherichia coli BL21(DE3)/pET28-CATHis and efficiently purified by heat treatment, achieving a threefold purification. The purified catalase was then immobilized onto an epoxy support at different temperatures (25, 40, and 55 °C). The immobilizate obtained at higher temperatures reached its maximum activity in a shorter time than that obtained at lower temperatures. Furthermore, immobilization at higher temperatures required a lower ionic strength than immobilization at lower temperatures. The characteristics of immobilized enzymes prepared at different temperatures were investigated. The high-temperature immobilizate (55 °C) showed the highest thermal stability, followed by the 40 °C immobilizate. And the high-temperature immobilizate (55 °C) had slightly higher operational stability than the 25 °C immobilizate. All of the immobilized catalase preparations showed higher stability than the free enzyme at alkaline pH 10.0, while the alkali resistance of the 25 °C immobilizate was slightly better than that of the 40 and 55 °C immobilizates.

Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

Science.gov (United States)

Cox, Sarah B.; Lui, Donovan; Gou, Jihua

2014-01-01

The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, which allows a shape to be formed prior to the cure, and is then pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Basalt fibers are used for the reinforcement in the composite system. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material.

Temperature uniformity mapping in a high pressure high temperature reactor using a temperature sensitive indicator

NARCIS (Netherlands)

Grauwet, T.; Plancken, van der I.; Vervoort, L.; Matser, A.M.; Hendrickx, M.; Loey, van A.

2011-01-01

Recently, the first prototype ovomucoid-based pressure–temperature–time indicator (pTTI) for high pressure high temperature (HPHT) processing was described. However, for temperature uniformity mapping of high pressure (HP) vessels under HPHT sterilization conditions, this prototype needs to be

Temperature field in the hot-top during casting a new super-high strength Al-Zn-Mg-Cu alloy by low frequency electromagnetic process

Directory of Open Access Journals (Sweden)

Yubo ZUO

2005-08-01

Full Text Available The billets of a new super-high strength Al-Zn-Mg-Cu alloy in 200 mm diameter were produced by the processed of low frequency electromagnetic casting (LFEC and conventional direct chill(DCcasting, respectively. The effects of low frequency electromagnetic field on temperature field of the melt in the hot-top were investigated by temperature thermocouples into the casting during the processes. The results show that during LFEC process the temperature field in the melt applying the hot-top is very uniform, which is helpful to reduce the difference of thermal gradients between the surface and the center, and then to reduce the thermal stress and to eliminate casting crack.

The effect of temperature and addition of reducing agent on sodium stannate preparation from cassiterite by the alkaline roasting process

Science.gov (United States)

Lalasari, Latifa Hanum; Andriyah, Lia; Arini, Tri; Firdiyono, F.

2018-04-01

Sodium stannate is an intermediate compound with the formula Na2SnO3. This compound is easily dissolved in water and has many applications in the electroplating industry, tin alloy production, and catalysts for organic synthesis. In this occasion was investigated the effect of temperature and the addition of reducing agent on making of sodium stannate phase from cassiterite by an alkaline roasting process using sodium carbonate (Na2CO3). Firstly, cassiterite was roasted at 700 °C for 3 hours and continued leaching process using 10% HCl solution at 110 °C for 2 hours. The cassiterite residue than was dried at 110 °C and mixed homogenously with a Na2CO3 decomposer at a mass ratio Na2CO3/cassiterite as 5:3 for the decomposition process. It was done by variation temperatures (300 °C, 700 °C, 800 °C, 870 °C, 900 °C) for 3 hours, variation times (3, 4, 5 hours) at a roasting temperature of 700 °C and addition of reducing agent such as sub-bituminous coal. The result of the experiment shows that cassiterite prepared by roasting and acid leaching process has the chemical composition as follows: 59.98% Sn, 22.58% O, 3.20% Ce, 3.15% La, 2.57% Nd, 1.67% Ti, 1.56% Fe, 1.24% P, 0.62% Ca and others. The Na2SnO3 phase begins to form at a roasting temperature of 870 °C for 3 hours. Although the roasting times was extended from 3 hours to 5 hours at 700 °C, the Na2SnO3 phase also has not yet formed. In other conditions, the addition of coal reducing agent to the roasting process would cause formations of Sn metal besides Na2SnO3 phase at 870 °C. At temperatures lower than 870 °C, the addition of coal only forms Sn metal, whereas the sodium stannate phase is not formed.

High Temperature Advanced Structural Composites. Volume 2. Ceramic Matrix Composites, Fiber Processing and Properties, and Interfaces

Science.gov (United States)

1993-04-02

furfural . toughness and a pseudoplasticity. the latter of treated to a higher temperature. The mamx or acetylenic resins provide simple processing...crystalline by TU/SAD and has an effective surface area of 250 m /go based on BET measurments with N2 adsorption . This solid crystallizes to high purity

Development of a high temperature microbial fermentation process for butanol

Energy Technology Data Exchange (ETDEWEB)

Jeor, Jeffery D. St. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Reed, David W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Daubaras, Dayna L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Thompson, Vicki S. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-08-01

Transforming renewable biomass into cost-competitive high-performance biofuels and bioproducts is key to the U.S. future energy and chemical needs. Butanol production by microbial fermentation for chemical conversion to polyolefins, elastomers, drop-in jet or diesel fuel, and other chemicals is a promising solution. A high temperature fermentation process could decrease energy costs, capital cost, give higher butanol production, and allow for continuous fermentation. In this paper, we describe our approach to genetically transform Geobacillus caldoxylosiliticus, using a pUCG18 plasmid, for potential insertion of a butanol production pathway. Transformation methods tested were electroporation of electrocompetent cells, ternary conjugation with E. coli donor and helper strains, and protoplast fusion. These methods have not been successful using the current plasmid. Growth controls show cells survive the various methods tested, suggesting the possibility of transformation inhibition from a DNA restriction modification system in G. caldoxylosiliticus, as reported in the literature.

Sintering and characterization of SrBi_2Ta_2O_9 obtained by high-pressure processing at low temperatures

International Nuclear Information System (INIS)

Souza, Ricson R.; Kirchner, Rejane K.; Jurado, Jose R.; Pereira, Altair S.; Sousa, Vânia C.

2016-01-01

High-pressure processing is a very attractive approach for the production of materials with new and/or improved properties. In this work, pressures in the order of 7.7 GPa and 2.5 GPa were induced in SrBi_2Ta_2O_9 samples at different temperatures placed in a specific reaction cell and generated different effects on phase formation. The microstructural evolution during high-pressure processing was investigated by scanning electron microscopy in association with energy dispersion spectroscopy and with the support of an X-ray diffraction analyzer. Frequency response analysis was used to obtain the dielectric curves by electrochemical impedance spectroscopy. A SrBi_2Ta_2O_9 single-phase sample, treated at 2.5 GPa and 900 °C, was used to evaluate the electrical properties, obtaining a dielectric response similar to SrBi_2Ta_2O_9 samples sintered by conventional processes at temperatures above 1000 °C. In addition, by this method, it was possible to obtain ceramics with uniform microstructure and a relative density of 93%. - Highlights: • The first production of SrBi_2Ta_2O_9 using the technique of high-pressure processing. • The ability to produce single-phase SrBi_2Ta_2O_9 treated at 2.5 GPa and 900 °C. • The electrical properties are compatible with SBT sintered at high temperatures.

Research and development on is process components for hydrogen production. (2) Corrosion resistance of glass lining in high temperature sulfuric acid

International Nuclear Information System (INIS)

Tanaka, Nobuyuki; Iwatsuki, Jin; Kubo, Shinji; Terada, Atsuhiko; Onuki, Kaoru

2009-01-01

Japan Atomic Energy Agency has been conducting a research and development on hydrogen production system using High Temperature Gas-Cooled Reactor. As a part of this effort, thermochemical water-splitting cycle featuring iodine- and sulfur-compounds (IS process) is under development considering its potential of large-scale economical hydrogen production. The IS process constitutes very severe environments on the materials of construction because of the corrosive nature of process chemicals, especially of the high temperature acidic solution of sulfuric acid and hydriodic acid dissolving iodine. Therefore, selection of the corrosion-resistant materials and development of the components has been studied as a crucial subject of the process development. This paper discusses corrosion resistance of commercially available glass-lining material in high temperature sulfuric acid. Corrosion resistance of a soda glass used for glass-lining was examined by immersion tests. The experiments were performed in 47-90wt% sulfuric acids at temperatures of up to 400degC and for the maximum immersion time of 100 hours using an autoclave designed for the concerned tests. In every condition tested, no indication of localized corrosion such as defect formation or pitting corrosion was observed. Also, the corrosion rates decreased with the progress of immersion, and were low enough (≅0.1 mm/year) after 60-90 hours of immersion probably due to formation of a silica rich surface. (author)

SIMULATION TOOL OF VELOCITY AND TEMPERATURE PROFILES IN THE ACCELERATED COOLING PROCESS OF HEAVY PLATES

Directory of Open Access Journals (Sweden)

Antônio Adel dos Santos

2014-10-01

Full Text Available The aim of this paper was to develop and apply mathematical models for determining the velocity and temperature profiles of heavy plates processed by accelerated cooling at Usiminas’ Plate Mill in Ipatinga. The development was based on the mathematical/numerical representation of physical phenomena occurring in the processing line. Production data from 3334 plates processed in the Plate Mill were used for validating the models. A user-friendly simulation tool was developed within the Visual Basic framework, taking into account all steel grades produced, the configuration parameters of the production line and these models. With the aid of this tool the thermal profile through the plate thickness for any steel grade and dimensions can be generated, which allows the tuning of online process control models. The simulation tool has been very useful for the development of new steel grades, since the process variables can be related to the thermal profile, which affects the mechanical properties of the steels.

Synthetic fuel production using Texas lignite and a very high temperature reactor for process heat

International Nuclear Information System (INIS)

Ross, M.A.; Klein, D.E.

1982-01-01

Two approaches for synthetic fuel production from coal are studied using Texas lignite as the feedstock. First, the gasification and liquefaction of coal are accomplished using Lurgi gasifiers and Fischer-Tropsch synthesis. A 50 000 barrel/day facility, consuming 13.7 million tonne/yr (15.1 million ton/yr) of lignite, is considered. Second, a nuclear-assisted coal conversion approach is studied using a very high temperature gas-cooled reactor with a modified Lurgi gasifier and Fischer-Tropsch synthesis. The nuclear-assisted approach resulted in a 35% reduction in coal consumption. In addition, process steam consumption was reduced by one-half and the oxygen plants were eliminated in the nuclear assisted process. Both approaches resulted in a synthetic oil price higher than the March 1980 imported price of $29.65 per barrel: $36.15 for the lignite-only process and $35.16 for the nuclear-assisted process. No tax advantage was assumed for either process and the utility financing method was used for both economic calculations

Microstructure and High Temperature Plastic Deformation Behavior of Al-12Si Based Alloy Fabricated by an Electromagnetic Casting and Stirring Process

Energy Technology Data Exchange (ETDEWEB)

Jeon, Kyung-Soo; Roh, Heung-Ryeol; Kim, Mok-Soon [Inha University, Incheon (Korea, Republic of); Kim, Jong-Ho; Park, Joon-Pyo [Research Institute of Industrial Science and Technology, Pohang (Korea, Republic of)

2017-06-15

An as-received EMC/S (electromagnetic casting and stirring)-processed Al-12Si based alloy billet was homogenized to examine its microstructure and high temperature plastic deformation behavior, using compressive tests over the temperature range from 623 to 743 K and a strain rate range from 1.0×10{sup -3} to 1.0×10{sup 0}s{sup -1}. The results were compared with samples processed by the direct chill casting (DC) method. The fraction of equiaxed structure for the as-received EMC/S billet(41%) was much higher than that of the as-received DC billet(6 %). All true stress – true strain curves acquired from the compressive tests exhibited a peak stress at the initial stage of plastic deformation. Flow stress showed a steady state region after the appearance of peak stress with increasing strain. The peak stress decreased with increasing temperature at a given strain rate and a decreasing strain rate at a given temperature. A constitutive equation was made for each alloy, which could be used to predict the peak stress. A recrystallized grain structure was observed in all the deformed specimens, indicating that dynamic recrystallization is the predominant mechanism during high temperature plastic deformation of both the homogenized EMC/S and DC-processed Al-12Si based alloys.

Effect of Temperature and Nutrient Concentration on Survival of Foodborne Pathogens in Deciduous Fruit Processing Environments for Effective Hygiene Management.

Science.gov (United States)

Duvenage, Stacey; Korsten, Lise

2016-11-01

Temperature and good sanitation practices are important factors for controlling growth of microorganisms. Fresh produce is stored at various temperatures to ensure quality and to prolong shelf life. When foodborne pathogens survive and grow on fresh produce at storage temperatures, then additional control strategies are needed to inactivate these pathogens. The aim of this study was to determine how temperatures associated with deciduous fruit processing and storage facilities (0.5, 4, and 21°C) affect the growth and/or survival of Escherichia coli O157:H7, Listeria monocytogenes , Salmonella enterica subsp. enterica serovar Typhimurium, and Staphylococcus aureus under different nutrient conditions (nutrient rich and nutrient poor) and on simulated contact surfaces (vinyl coupons). Information on the growth and survival of foodborne pathogens at specific deciduous fruit processing and storage temperatures (0.5°C) is not available. All pathogens except E. coli O157:H7 were able to survive on vinyl coupons at all temperatures. L. monocytogenes proliferated under both nutrient conditions independent of temperature. S. aureus was the pathogen least affected by nutrient conditions. The survival of foodborne pathogens on the vinyl coupons, a model system for studying surfaces in fruit preparation and storage environments, indicates the potential for cross-contamination of deciduous fruit products under poor sanitation conditions. Foodborne pathogens that can proliferate and survive at various temperatures under different nutrient conditions could lead to fruit cross-contamination. Temperature mismanagement, which could allow pathogen proliferation in contaminated fruit packing houses and storage environments, is a concern. Therefore, proper hygiene and sanitation practices, removal of possible contaminants, and proper food safety management systems are needed to ensure food safety.

Porous aluminum room temperature anodizing process in a fluorinated-oxalic acid solution

Science.gov (United States)

Dhahri, S.; Fazio, E.; Barreca, F.; Neri, F.; Ezzaouia, H.

2016-08-01

Anodizing of aluminum is used for producing porous insulating films suitable for different applications in electronics and microelectronics. Porous-type aluminum films are most simply realized by galvanostatic anodizing in aqueous acidic solutions. The improvement in application of anodizing technique is associated with a substantial reduction of the anodizing voltage at appropriate current densities as well as to the possibility to carry out the synthesis process at room temperature in order to obtain a self-planarizing dielectric material incorporated in array of super-narrow metal lines. In this work, the anodizing of aluminum to obtain porous oxide was carried out, at room temperature, on three different substrates (glass, stainless steel and aluminum), using an oxalic acid-based electrolyte with the addition of a relatively low amount of 0.4 % of HF. Different surface morphologies, from nearly spherical to larger porous nanostructures with smooth edges, were observed by means of scanning electron microscopy. These evidences are explained by considering the formation, transport and adsorption of the fluorine species which react with the Al3+ ions. The behavior is also influenced by the nature of the original substrate.

High temperature structural ceramic materials manufactured by the CNTD process

International Nuclear Information System (INIS)

Stiglich, J.J. Jr.; Bhat, D.G.; Holzl, R.A.

1980-01-01

Controlled Nucleation Thermochemical Deposition (CNTD) has emerged from classical chemical deposition (CVD) technology. This paper describes the techniques of thermochemical grain refinement. The effects of such refinement on mechanical properties of materials at room temperature and at elevated temperatures are outlined. Emphasis is given to high temperature structural ceramic materials such as SiC, Si 3 N 4 , AlN, and TiB 2 and ZrB 2 . An example of grain refinement accompanied by improvements in mechanical properties is SiC. Grain sizes of 500 to 1000 A have been observed in CNTD SiC with room temperature MOR of 1380 to 2070 MPa (4 pt bending) and MOR of 3450 to 4140 MPa (4 pt bending) at 1350 0 C. Various applications of these materials to the solution of high temperature structural problems are described. (author)

Low-temperature bonding process for the fabrication of hybrid glass-membrane organ-on-a-chip devices

Science.gov (United States)

Pocock, Kyall J.; Gao, Xiaofang; Wang, Chenxi; Priest, Craig; Prestidge, Clive A.; Mawatari, Kazuma; Kitamori, Takehiko; Thierry, Benjamin

2016-10-01

The integration of microfluidics with living biological systems has paved the way to the exciting concept of "organs-on-a-chip," which aims at the development of advanced in vitro models that replicate the key features of human organs. Glass-based devices have long been utilized in the field of microfluidics but the integration of alternative functional elements within multilayered glass microdevices, such as polymeric membranes, remains a challenge. To this end, we have extended a previously reported approach for the low-temperature bonding of glass devices that enables the integration of a functional polycarbonate porous membrane. The process was initially developed and optimized on specialty low-temperature bonding equipment (μTAS2001, Bondtech, Japan) and subsequently adapted to more widely accessible hot embosser units (EVG520HE Hot Embosser, EVG, Austria). The key aspect of this method is the use of low temperatures compatible with polymeric membranes. Compared to borosilicate glass bonding (650°C) and quartz/fused silica bonding (1050°C) processes, this method maintains the integrity and functionality of the membrane (Tg 150°C for polycarbonate). Leak tests performed showed no damage or loss of integrity of the membrane for up to 150 h, indicating sufficient bond strength for long-term cell culture. A feasibility study confirmed the growth of dense and functional monolayers of Caco-2 cells within 5 days.

Investigation of Coupled Processes and Impact of High Temperature Limits in Argillite Rock

International Nuclear Information System (INIS)

Zheng, Liange; Rutqvist, Jonny; Kim, Kunhwi; Houseworth, Jim

2015-01-01

The focus of research within the UFD Campaign is on repository-induced interactions that may affect the key safety characteristics of an argillaceous rock. These include thermal-hydrological-mechanical-chemical (THMC) process interactions that occur as a result of repository construction and waste emplacement. Some of the key questions addressed in this report include the development of fracturing in the excavation damaged zone (EDZ) and THMC effects on the near-field argillaceous rock and buffer minerals and petrophysical characteristics, particularly the impacts of induced temperature rise caused by waste heat.

Investigation of Coupled Processes and Impact of High Temperature Limits in Argillite Rock

Energy Technology Data Exchange (ETDEWEB)

Zheng, Liange [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rutqvist, Jonny [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kim, Kunhwi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Houseworth, Jim [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2015-07-01

The focus of research within the UFD Campaign is on repository-induced interactions that may affect the key safety characteristics of an argillaceous rock. These include thermal-hydrological-mechanical-chemical (THMC) process interactions that occur as a result of repository construction and waste emplacement. Some of the key questions addressed in this report include the development of fracturing in the excavation damaged zone (EDZ) and THMC effects on the near-field argillaceous rock and buffer minerals and petrophysical characteristics, particularly the impacts of induced temperature rise caused by waste heat.

Investigation of Mercury Reduction in Gold Stripping Process at Elevated Temperature

Science.gov (United States)

Pramudya, Irawan

Mercury is present in many gold ores. By processing these ores, there is a potential of emitting mercury to the environment. Carbon regeneration kiln stacks have been observed as one of the primary source of mercury emission into the atmosphere. Before it is recycled back into the carbon in leach (CIL) or carbon in columns (CIC), carbon used in the gold extraction process needs to be reactivated thermally. Emission of mercury can be minimized by keeping the mercury left in the carbon low before it goes to the carbon regeneration kiln stacks. The objective of this study is establishing the optimum elution conditions of mercury cyanide from loaded carbon (which includes the eluent, concentration, temperature and elution time) with respect to gold stripping. Several methods such as acid washing (UNR-100, HCl or ethanol/UNR-100) were investigated prior to the stripping process. Furthermore, conventional pressurized Zadra and modified Zadra were also studied with regards to mercury concentration in the solution and vapor state as well as maximizing the gold stripping from industrial loaded carbon. 7% UNR-100 acid washing of loaded carbon at 80°C was able to wash out approximately 90% of mercury while maintaining the gold adsorption on the carbon (selective washing). The addition of alcohol in the UNR-100 acid washing solution was able to enhance mercury washing from 90% to 97%. Furthermore, mercury stripping using conventional pressurized (cyanide-alkaline) Zadra was best performed at 80°C (minimal amount of mercury reduced and volatilized) whereas using the same process only 40% of gold was stripped, which makes this process not viable. When alcohol was added to the stripping solution, at 80°C, 95% of gold was detected in the solution while keeping the reduction and volatilization of mercury low. The outcome of this study provides a better understanding of mercury behavior during the acid washing and stripping processes so that the risk of mercury exposure and

Effect Of The Desorption-Recombination Temperature On The Microstructure And Magnetic Properties Of HDDR Processed Nd-Fe-B Powders

Directory of Open Access Journals (Sweden)

Lee J.-G.

2015-06-01

Full Text Available The effect of the desorption-recombination temperature on the microstructure and magnetic properties of hydrogenation-disproportionation-desorption-recombination (HDDR processed Nd-Fe-B powders was studied. The NdxB6.4Ga0.3Nb0.2Febal (x=12.5-13.5, at.% casting alloys were pulverized after homogenizing annealing, and then subjected to HDDR treatment. During the HDDR process, desorption-recombination (DR reaction was induced at two different temperature, 810°C and 820°C. The higher Nd content resulted in enhanced coercivity of the HDDR powder, and which was attributed to the thicker and more uniform Nd-rich phase along grain boundaries. But this uniform Nd-rich phase induced faster grain growth. The remanence of the powder DR-treated at 820°C is higher than that DR-treated at 810°C. In addition, it was also confirmed that higher DR temperature is much more effective to improve squareness.

Thermomechanical processing of Nb-1Zr-0.1C alloy for use in compact high temperature reactors: a first report

International Nuclear Information System (INIS)

Chakravartty, J.K.; Kapoor, R.; Suri, A.K.

2011-08-01

Nb-1Zr-0.1C is a potential material for use in high temperature nuclear reactors. Use of this alloy in components requires appropriate thermomechanical processing to break the cast microstructure and to obtain uniformly distributed fine stable precipitates so as to produce the desired mechanical properties at the high operating temperatures. This report reviews the thermomechanical processing of Nb-1Zr-0.1C alloy carried out over the years by other researchers and the high temperature creep behavior of the alloy. The hot deformation of Nb-1Zr-0.1C alloy carried out at Mechanical Metallurgy Division is also presented here. From this review it is evident that most primary hot working studies were carried out between 1500 to 1700 degC. The subsequent annealing treatments, which require holding at lower temperatures of about 1100 to 1300 degC for very long times help further transform the precipitates from coarse orthorhombic to very fine cubic. Our studies on Nb-1Zr-0.1C alloy also confirm that optimum hot working lies at temperatures beyond 1500 degC where dynamic recrystallization initiates, and optimally around 1700 degC where dynamic recrystallization transforms the microstructure. Working at temperatures lower than 1000 degC may lead to the undesirable effect of both micro as well as macro strain localization, and should be avoided. (author)

Aluminizing of steel 316L and the nickel-base alloy inconel 625 and followed by a high-temperature oxidation process

International Nuclear Information System (INIS)

Skokanova, P.; Glasbrenner, H.; Zimmermann, H.

1995-03-01

The supercritical water oxidation process of hazardous waste has to be carried out in a reactor which is resistant against corrosion and high pressure and temperature. Pressure tube materials are coated for protection against corrosion. In this work, the reactor materials Inconel 625 and steel 316L have been powder pack aluminized. These coated specimens were subsequently oxidized. Powder mixtures of different composition were tested, time and temperature of the coating and the oxidation processes were varied. Good results were obtained on the steel 316L in respect to thickness of the layer, composition, and adherence on the steel. (orig.)

Mathematical model to predict temperature profile and air–fuel equivalence ratio of a downdraft gasification process

International Nuclear Information System (INIS)

Jaojaruek, Kitipong

2014-01-01

Highlights: • A mathematical model based on finite computation analysis was developed. • Model covers all zones of gasification process which will be useful to improve gasifier design. • Model can predict temperature profile, feedstock consumption rate and reaction equivalent ratio (ϕ). • Model-predicted parameters fitted well with experimental values. - Abstract: A mathematical model for the entire length of a downdraft gasifier was developed using thermochemical principles to derive energy and mass conversion equations. Analysis of heat transfer (conduction, convection and radiation) and chemical kinetic technique were applied to predict the temperature profile, feedstock consumption rate (FCR) and reaction equivalence ratio (RER). The model will be useful for designing gasifiers, estimating output gas composition and gas production rate (GPR). Implicit finite difference method solved the equations on the considered reactor length (50 cm) and diameter (20 cm). Conversion criteria for calculation of temperature and feedstock consumption rate were 1 × 10 −6 °C and 1 × 10 −6 kg/h, respectively. Experimental validation showed that model outputs fitted well with experimental data. Maximum deviation between model and experimental data of temperature, FCR and RER were 52 °C at combustion temperature 663 °C, 0.7 kg/h at the rate 8.1 kg/h and 0.03 at the RER 0.42, respectively. Experimental uncertainty of temperature, FCR and RER were 24.4 °C, 0.71 kg/h and 0.04, respectively, on confidence level of 95%

Chapter 6: Temperature

Science.gov (United States)

Jones, Leslie A.; Muhlfeld, Clint C.; Hauer, F. Richard; F. Richard Hauer,; Lamberti, G.A.

2017-01-01

Stream temperature has direct and indirect effects on stream ecology and is critical in determining both abiotic and biotic system responses across a hierarchy of spatial and temporal scales. Temperature variation is primarily driven by solar radiation, while landscape topography, geology, and stream reach scale ecosystem processes contribute to local variability. Spatiotemporal heterogeneity in freshwater ecosystems influences habitat distributions, physiological functions, and phenology of all aquatic organisms. In this chapter we provide an overview of methods for monitoring stream temperature, characterization of thermal profiles, and modeling approaches to stream temperature prediction. Recent advances in temperature monitoring allow for more comprehensive studies of the underlying processes influencing annual variation of temperatures and how thermal variability may impact aquatic organisms at individual, population, and community based scales. Likewise, the development of spatially explicit predictive models provide a framework for simulating natural and anthropogenic effects on thermal regimes which is integral for sustainable management of freshwater systems.

Antimony assisted low-temperature processing of CuIn{sub 1-x}Ga{sub x}Se{sub 2-y}S{sub y} solar cells

Energy Technology Data Exchange (ETDEWEB)

Min, Yuan [IBM T. J. Watson Research Center, P. O. Box 218, Yorktown Heights, NY 10598 (United States); Mitzi, David B., E-mail: dmitzi@us.ibm.co [IBM T. J. Watson Research Center, P. O. Box 218, Yorktown Heights, NY 10598 (United States); Gunawan, Oki [IBM T. J. Watson Research Center, P. O. Box 218, Yorktown Heights, NY 10598 (United States); Kellock, Andrew J [IBM Almaden Research Center, 650 Harry Rd, San Jose, CA 95120 (United States); Chey, S Jay [IBM T. J. Watson Research Center, P. O. Box 218, Yorktown Heights, NY 10598 (United States); Deline, Vaughn R [IBM Almaden Research Center, 650 Harry Rd, San Jose, CA 95120 (United States)

2010-11-01

Application of the Sb-doping method to low-temperature ({<=} 400 {sup o}C) processing of CuIn{sub 1-x}Ga{sub x}Se{sub 2-y}S{sub y} (CIGS) solar cells is explored, using a hydrazine-based approach to deposit the absorber films. Power conversion efficiencies of 10.5% and 8.4% have been achieved for CIGS devices (0.45 cm{sup 2} device area) processed at 400 {sup o}C and 360 {sup o}C, respectively, with an Sb-incorporation level at 1.2 mol % (relative to the moles of CIGS). Significant Sb-induced grain size enhancement was confirmed for these low processing temperatures using cross-sectional scanning electron microscopy, and an average 2-3% absolute efficiency improvement was achieved in Sb-doped samples compared to their Sb-free sister samples. With Sb inclusion, the CIGS film grain growth temperature is lowered to well below 450 {sup o}C, a range compatible with flexible polymer substrate materials such as polyimide. This method opens up access to opportunities in low-temperature processing of CIGS solar cells, an area that is being actively pursued using both traditional vacuum-based as well as other solution-based deposition techniques.

Materials process and applications of single grain (RE)-Ba-Cu-O bulk high-temperature superconductors

Energy Technology Data Exchange (ETDEWEB)

Li Beizhan; Zhou Difan; Xu Kun; Hara, Shogo; Tsuzuki, Keita; Miki, Motohiro; Felder, Brice; Deng Zigang [Laboratory of Applied Physics, Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology (TUMSAT), 2-1-6, Etchu-jima, Koto-ku, Tokyo 135-8533 (Japan); Izumi, Mitsuru, E-mail: izumi@kaiyodai.ac.jp [Laboratory of Applied Physics, Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology (TUMSAT), 2-1-6, Etchu-jima, Koto-ku, Tokyo 135-8533 (Japan)

2012-11-20

This paper reviews recent advances in the melt process of (RE)-Ba-Cu-O [(RE)BCO, where RE represents a rare earth element] single grain high-temperature superconductors (HTSs), bulks and its applications. The efforts on the improvement of the magnetic flux pinning with employing the top-seeded melt-growth process technique and using a seeded infiltration and growth process are discussed. Which including various chemical doping strategies and controlled pushing effect based on the peritectic reaction of (RE)BCO. The typical experiment results, such as the largest single domain bulk, the clear TEM observations and the significant critical current density, are summarized together with the magnetization techniques. Finally, we highlight the recent prominent progress of HTS bulk applications, including Maglev, flywheel, power device, magnetic drug delivery system and magnetic resonance devices.

Materials process and applications of single grain (RE)-Ba-Cu-O bulk high-temperature superconductors

Science.gov (United States)

Li, Beizhan; Zhou, Difan; Xu, Kun; Hara, Shogo; Tsuzuki, Keita; Miki, Motohiro; Felder, Brice; Deng, Zigang; Izumi, Mitsuru

2012-11-01

This paper reviews recent advances in the melt process of (RE)-Ba-Cu-O [(RE)BCO, where RE represents a rare earth element] single grain high-temperature superconductors (HTSs), bulks and its applications. The efforts on the improvement of the magnetic flux pinning with employing the top-seeded melt-growth process technique and using a seeded infiltration and growth process are discussed. Which including various chemical doping strategies and controlled pushing effect based on the peritectic reaction of (RE)BCO. The typical experiment results, such as the largest single domain bulk, the clear TEM observations and the significant critical current density, are summarized together with the magnetization techniques. Finally, we highlight the recent prominent progress of HTS bulk applications, including Maglev, flywheel, power device, magnetic drug delivery system and magnetic resonance devices.

New alternatives for the fermentation process in the ethanol production from sugarcane: Extractive and low temperature fermentation

International Nuclear Information System (INIS)

Palacios-Bereche, Reynaldo; Ensinas, Adriano; Modesto, Marcelo; Nebra, Silvia A.

2014-01-01

Ethanol is produced in large scale from sugarcane in Brazil by fermentation of sugars and distillation. This is currently considered as an efficient biofuel technology, leading to significant reduction on greenhouse gases emissions. However, some improvements in the process can be introduced in order to improve the use of energy. In current distilleries, a significant fraction of the energy consumption occurs in the purification step – distillation and dehydration – since conventional fermentation systems employed in the industry require low substrate concentration, which must be distilled, consequently with high energy consumption. In this study, alternatives to the conventional fermentation processes are assessed, through computer simulation: low temperature fermentation and vacuum extractive fermentation. The aim of this study is to assess the incorporation of these alternative fermentation processes in ethanol production, energy consumption and electricity surplus produced in the cogeneration system. Several cases were evaluated. Thermal integration technique was applied. Results shown that the ethanol production increases between 3.3% and 4.8% and a reduction in steam consumption happens of up to 36%. About the electricity surplus, a value of 85 kWh/t of cane can be achieved when condensing – extracting steam turbines are used. - Highlights: • Increasing the wine concentration in the ethanol production from sugarcane. • Alternatives to the conventional fermentation process. • Low temperature fermentation and vacuum extractive fermentation. • Reduction of steam consumption through the thermal integration of the processes. • Different configurations of cogeneration system maximizing the electricity surplus

Microstructures and mechanical behavior of magnesium processed by ECAP at ice-water temperature

Science.gov (United States)

Zuo, Dai; Li, Taotao; Liang, Wei; Wen, Xiyu; Yang, Fuqian

2018-05-01

Magnesium of high purity is processed by equal channel angular pressing (ECAP) up to eight passes at the ice-water temperature, in which a core–shell-like structure is used. The core–shell-like structure consists of pure iron (Fe) of 1.5 mm in thickness as the shell and magnesium (Mg) as the core. The microstructure, texture and mechanical behavior of the ECAP-processed Mg are studied. The ECAP processing leads to the formation of fine and equiaxed grains of ~1.1 µm. The basal planes initially parallel to the extrusion direction evolve to slanted basal planes with the tilting angle in a range of 25°–45° to the extrusion direction. Increasing the number of the extrusion passes leads to the decreasing of twins and dislocation density in grains, while individual grains after eight passes still have high dislocation density. The large decreases of twins and the dislocation density make dynamic recrystallization (DRX) difficult, resulting in the decrease of the degree of DRX. Tension test reveals that the mechanical behavior of the ECAP-processed Mg is dependent on grain refinement and textures. The yield strength of the ECAP-extruded Mg first increases with the decrease of the grain size, and then decreases with further decrease of the grain size.

Strain and temperature measurement in pultrusion processes by fiber Bragg grating sensors

Science.gov (United States)

Tucci, Fausto; Rubino, Felice; Carlone, Pierpaolo

2018-05-01

Injection Pultrusion (IP) is one of the most effective processes, in terms of productivity and costs, to manufacture fiber reinforced polymers. In IP roving of fiber are driven through an injection chamber in which they are impregnated by the resin and then formed in a shaped die. The die is heated in order to cure the resin. Pultruded products are in most cases characterized by constant cross-section profile, whereas unidirectional long fibers are mainly used as reinforcing material. Two relevant phenomena occur within the injection chamber and the heated die, namely the impregnation of the fibers and the polymerization of the resin. Furthermore, thermal expansion, resin chemical shrinkage and the interaction between the die and the impregnated fibers strongly influence the process [1]. Clearly, thermal and mechanical fields significantly impact on these strictly chained behaviours. The use of thermocouples to evaluate temperature within pultrusion die is already widespread, but they are not capable to acquire any information concerning stress-strain levels. In the present work Fibers Bragg Gratings (FBG) sensors were used to measure thermal and strain profiles in selected material location within the injection chamber and the curing die. Being the differences among the spectres transmitted and received are related to the variations in both temperature and strain, commercial FBG sensors were opportunely modified and calibrated. The optical fibers were hooked to the fibers entering into the injection pultrusion die. Taking the pulling speed into account, each waveform acquired was correlated to a position within the die. Obtained data highlight the effect of the heat generation due to resin reaction as well as longitudinal strains related to the pulling force, the thermal expansion and the chemical shrinkage of the resin system.

Real-time electrical impedimetric monitoring of blood coagulation process under temperature and hematocrit variations conducted in a microfluidic chip.

Directory of Open Access Journals (Sweden)

Kin Fong Lei

Full Text Available Blood coagulation is an extremely complicated and dynamic physiological process. Monitoring of blood coagulation is essential to predict the risk of hemorrhage and thrombosis during cardiac surgical procedures. In this study, a high throughput microfluidic chip has been developed for the investigation of the blood coagulation process under temperature and hematocrit variations. Electrical impedance of the whole blood was continuously recorded by on-chip electrodes in contact with the blood sample during coagulation. Analysis of the impedance change of the blood was conducted to investigate the characteristics of blood coagulation process and the starting time of blood coagulation was defined. The study of blood coagulation time under temperature and hematocrit variations was shown a good agreement with results in the previous clinical reports. The electrical impedance measurement for the definition of blood coagulation process provides a fast and easy measurement technique. The microfluidic chip was shown to be a sensitive and promising device for monitoring blood coagulation process even in a variety of conditions. It is found valuable for the development of point-of-care coagulation testing devices that utilizes whole blood sample in microliter quantity.

Effects of pressure and temperature on sintering of Cr-doped Al2O3 by pulsed electric current sintering process

Science.gov (United States)

Dang, K. Q.; Nanko, M.

2011-03-01

The aluminium oxide crystal, Al2O3, which contains a small amount of chromium, Cr, is called ruby. Pulsed electric current sintering (PECS) was applied to sinter ruby polycrystals. Cr2O3-Al2O3 powder mixture prepared by drying an aqueous slurry containing amounts of Al2O3 and Cr(NO3)3 was consolidated by PECS process. The PECS process was performed in vacuum at sintering temperature raging from 1100 to 1300°C with heating rate of 2 K/min under applied uniaxial pressure varied from 40 to 100 MPa. This study found that highly densified and transparent Cr-doped Al2O3 can be obtained by the PECS process with the high applied pressure at sintering temperature of 1200°C.

High temperature materials and mechanisms

CERN Document Server

2014-01-01

The use of high-temperature materials in current and future applications, including silicone materials for handling hot foods and metal alloys for developing high-speed aircraft and spacecraft systems, has generated a growing interest in high-temperature technologies. High Temperature Materials and Mechanisms explores a broad range of issues related to high-temperature materials and mechanisms that operate in harsh conditions. While some applications involve the use of materials at high temperatures, others require materials processed at high temperatures for use at room temperature. High-temperature materials must also be resistant to related causes of damage, such as oxidation and corrosion, which are accelerated with increased temperatures. This book examines high-temperature materials and mechanisms from many angles. It covers the topics of processes, materials characterization methods, and the nondestructive evaluation and health monitoring of high-temperature materials and structures. It describes the ...

Low-temperature atomic layer deposition of TiO2 thin layers for the processing of memristive devices

International Nuclear Information System (INIS)

Porro, Samuele; Conti, Daniele; Guastella, Salvatore; Ricciardi, Carlo; Jasmin, Alladin; Pirri, Candido F.; Bejtka, Katarzyna; Perrone, Denis; Chiolerio, Alessandro

2016-01-01

Atomic layer deposition (ALD) represents one of the most fundamental techniques capable of satisfying the strict technological requirements imposed by the rapidly evolving electronic components industry. The actual scaling trend is rapidly leading to the fabrication of nanoscaled devices able to overcome limits of the present microelectronic technology, of which the memristor is one of the principal candidates. Since their development in 2008, TiO 2 thin film memristors have been identified as the future technology for resistive random access memories because of their numerous advantages in producing dense, low power-consuming, three-dimensional memory stacks. The typical features of ALD, such as self-limiting and conformal deposition without line-of-sight requirements, are strong assets for fabricating these nanosized devices. This work focuses on the realization of memristors based on low-temperature ALD TiO 2 thin films. In this process, the oxide layer was directly grown on a polymeric photoresist, thus simplifying the fabrication procedure with a direct liftoff patterning instead of a complex dry etching process. The TiO 2 thin films deposited in a temperature range of 120–230 °C were characterized via Raman spectroscopy and x-ray photoelectron spectroscopy, and electrical current–voltage measurements taken in voltage sweep mode were employed to confirm the existence of resistive switching behaviors typical of memristors. These measurements showed that these low-temperature devices exhibit an ON/OFF ratio comparable to that of a high-temperature memristor, thus exhibiting similar performances with respect to memory applications

Increased temperature causes different carbon and nitrogen processing patterns in two common intertidal foraminifera (Ammonia tepida and Haynesina germanica)

Science.gov (United States)

Wukovits, Julia; Enge, Annekatrin Julie; Wanek, Wolfgang; Watzka, Margarete; Heinz, Petra

2017-06-01

Benthic foraminifera are highly abundant heterotrophic protists in marine sediments, but future environmental changes will challenge the tolerance limits of intertidal species. Metabolic rates and physiological processes in foraminifera are strongly dependent on environmental temperatures. Temperature-related stress could therefore impact foraminiferal food source processing efficiency and might result in altered nutrient fluxes through the intertidal food web. In this study, we performed a laboratory feeding experiment on Ammonia tepida and Haynesina germanica, two dominant foraminiferal species of the German Wadden Sea/Friedrichskoog, to test the effect of temperature on phytodetritus retention. The specimens were fed with 13C and 15N labelled freeze-dried Dunaliella tertiolecta (green algae) at the start of the experiment and were incubated at 20, 25 and 30 °C respectively. Dual labelling was applied to observe potential temperature effects on the relation of phytodetrital carbon and nitrogen retention. Samples were taken over a period of 2 weeks. Foraminiferal cytoplasm was isotopically analysed to investigate differences in carbon and nitrogen uptake derived from the food source. Both species showed a positive response to the provided food source, but carbon uptake rates of A. tepida were 10-fold higher compared to those of H. germanica. Increased temperatures had a far stronger impact on the carbon uptake of H. germanica than on A. tepida. A distinct increase in the levels of phytodetrital-derived nitrogen (compared to more steady carbon levels) could be observed over the course of the experiment in both species. The results suggest that higher temperatures have a significant negative effect on the carbon exploitation of H. germanica. For A. tepida, higher carbon uptake rates and the enhanced tolerance range for higher temperatures could outline an advantage in warmer periods if the main food source consists of chlorophyte phytodetritus. These conditions are

Process for the production of fuel combined articles for addition in block shaped high temperature fuel elements

International Nuclear Information System (INIS)

Hrovat, M.; Rachor, L.

1976-01-01

There is provided a process for the production of fuel compacts consisting of an isotropic, radiation-resistant graphite matrix of good heat conductivity having embedded therein coated fuel and/or fertile particles for insertion into high temperature fuel elements by providing the coated fuel and/or fertile particles with an overcoat of molding mixture consisting of graphite powder and a thermoplastic resin binder. The particles after the overcoating are provided with hardener and lubricant only on the surface and subsequently are compressed in a die heated to a constant temperature of about 150 0 C, hardened and discharged therefrom as finished compacts

OPTIMAL SYSNTHESIS PROCESSES OF LOW-TEMPERATURE CONDENSATION ASSOCIATED OIL GAS PLANT REFRIGERATION SYSTEM

Directory of Open Access Journals (Sweden)

O. Ostapenko

2015-10-01

Full Text Available Design of modern high-efficient systems is a key priority for the Energy Sector of Ukraine. The cooling technological streams of gas and oil refineries, including air coolers, water cooling and refrigeration systems for specific refrigerants are the objectives of the present study. Improvement of the refrigeration unit with refrigerant separation into fractions is mandatory in order to increase cooling capacity, lowering the boiling point of coolant and increasing the coefficient of target hydrocarbons extraction from the associated gas flow. In this paper it is shown that cooling temperature plays significant role in low-temperature condensation process. Two operation modes for refrigeration unit were proposed: permanent, in which the concentration of the refrigerant mixture does not change and dynamic, in which the concentration of refrigerant mixtures depends on the ambient temperature. Based on the analysis of exergy losses the optimal concentration of refrigerant mixtures propane/ethane for both modes of operation of the refrigeration unit has been determined. On the basis of the conducted pinch-analysis the modification of refrigeration unit with refrigerant separation into fractions was developed. Additional recuperative heat exchangers for utilization heat were added to the scheme. Several important measures to increase the mass flow rate of refrigerant through the second section of the refrigeration centrifugal compressor from 22.5 to 25 kg/s without violating the agreed operational mode of the compressor sections were implemented.

The effect of High Pressure and High Temperature processing on carotenoids and chlorophylls content in some vegetables.

Science.gov (United States)

Sánchez, Celia; Baranda, Ana Beatriz; Martínez de Marañón, Iñigo

2014-11-15

The effect of High Pressure (HP) and High Pressure High Temperature (HPHT) processing on carotenoid and chlorophyll content of six vegetables was evaluated. In general, carotenoid content was not significantly influenced by HP or HPHT treatments (625 MPa; 5 min; 20, 70 and 117 °C). Regarding chlorophylls, HP treatment caused no degradation or slight increases, while HPHT processes degraded both chlorophylls. Chlorophyll b was more stable than chlorophyll a at 70 °C, but both of them were highly degraded at 117 °C. HPHT treatment at 117 °C provided products with a good retention of carotenoids and colour in the case of red vegetables. Even though the carotenoids also remained in the green vegetables, their chlorophylls and therefore their colour were so affected that milder temperatures need to be applied. As an industrial scale equipment was used, results will be useful for future industrial implementation of this technology. Copyright © 2014 Elsevier Ltd. All rights reserved.

Room-Temperature-Processed Flexible Amorphous InGaZnO Thin Film Transistor.

Science.gov (United States)

Xiao, Xiang; Zhang, Letao; Shao, Yang; Zhou, Xiaoliang; He, Hongyu; Zhang, Shengdong

2017-12-13

A room-temperature flexible amorphous indium-gallium-zinc oxide thin film transistor (a-IGZO TFT) technology is developed on plastic substrates, in which both the gate dielectric and passivation layers of the TFTs are formed by an anodic oxidation (anodization) technique. While the gate dielectric Al 2 O 3 is grown with a conventional anodization on an Al:Nd gate electrode, the channel passivation layer Al 2 O 3 is formed using a localized anodization technique. The anodized Al 2 O 3 passivation layer shows a superior passivation effect to that of PECVD SiO 2 . The room-temperature-processed flexible a-IGZO TFT exhibits a field-effect mobility of 7.5 cm 2 /V·s, a subthreshold swing of 0.44 V/dec, an on-off ratio of 3.1 × 10 8 , and an acceptable gate-bias stability with threshold voltage shifts of 2.65 and -1.09 V under positive gate-bias stress and negative gate-bias stress, respectively. Bending and fatigue tests confirm that the flexible a-IGZO TFT also has a good mechanical reliability, with electrical performances remaining consistent up to a strain of 0.76% as well as after 1200 cycles of fatigue testing.

A process to fabricate fused silica nanofluidic devices with embedded electrodes using an optimized room temperature bonding technique

Science.gov (United States)

Boden, Seth; Karam, P.; Schmidt, A.; Pennathur, S.

2017-05-01

Fused silica is an ideal material for nanofluidic systems due to its extreme purity, chemical inertness, optical transparency, and native hydrophilicity. However, devices requiring embedded electrodes (e.g., for bioanalytical applications) are difficult to realize given the typical high temperature fusion bonding requirements (˜1000 °C). In this work, we optimize a two-step plasma activation process which involves an oxygen plasma treatment followed by a nitrogen plasma treatment to increase the fusion bonding strength of fused silica at room temperature. We conduct a parametric study of this treatment to investigate its effect on bonding strength, surface roughness, and microstructure morphology. We find that by including a nitrogen plasma treatment to the standard oxygen plasma activation process, the room temperature bonding strength increases by 70% (0.342 J/m2 to 0.578 J/m2). Employing this optimized process, we fabricate and characterize a nanofluidic device with an integrated and dielectrically separated electrode. Our results prove that the channels do not leak with over 1 MPa of applied pressure after a 24 h storage time, and the electrode exhibits capacitive behavior with a finite parallel resistance in the upper MΩ range for up to a 6.3Vdc bias. These data thus allow us to overcome the barrier that has barred nanofluidic progress for the last decade, namely, the development of nanometer scale well-defined channels with embedded metallic materials for far-reaching applications such as the exquisite manipulation of biomolecules.

Low temperature circulating fluidized bed gasification and co-gasification of municipal sewage sludge. Part 1: Process performance and gas product characterization

DEFF Research Database (Denmark)

Thomsen, Tobias Pape; Sárossy, Zsuzsa; Gøbel, Benny

2017-01-01

Results from five experimental campaigns with Low Temperature Circulating Fluidized Bed (LT-CFB) gasification of straw and/or municipal sewage sludge (MSS) from three different Danish municipal waste water treatment plants in pilot and demonstration scale are analyzed and compared. The gasification...... process is characterized with respect to process stability, process performance and gas product characteristics. All experimental campaigns were conducted at maximum temperatures below 750°C, with air equivalence ratios around 0.12 and with pure silica sand as start-up bed material. A total of 8600kg...... particles in the system. Co-gasification of MSS with sufficient amounts of cereal straw was found to be an effective way to mitigate these issues as well as eliminate thermal MSS drying requirements. Characterization of gas products and process performance showed that even though gas composition varied...

Direct and indirect toxicity of the fungicide pyraclostrobin to Hyalella azteca and effects on leaf processing under realistic daily temperature regimes.

Science.gov (United States)

Willming, Morgan M; Maul, Jonathan D

2016-04-01

Fungicides in aquatic environments can impact non-target bacterial and fungal communities and the invertebrate detritivores responsible for the decomposition of allochthonous organic matter. Additionally, in some aquatic systems daily water temperature fluctuations may influence these processes and alter contaminant toxicity, but such temperature fluctuations are rarely examined in conjunction with contaminants. In this study, the shredding amphipod Hyalella azteca was exposed to the fungicide pyraclostrobin in three experiments. Endpoints included mortality, organism growth, and leaf processing. One experiment was conducted at a constant temperature (23 °C), a fluctuating temperature regime (18-25 °C) based on field-collected data from the S. Llano River, Texas, or an adjusted fluctuating temperature regime (20-26 °C) based on possible climate change predictions. Pyraclostrobin significantly reduced leaf shredding and increased H. azteca mortality at concentrations of 40 μg/L or greater at a constant 23 °C and decreased leaf shredding at concentrations of 15 μg/L or greater in the fluctuating temperatures. There was a significant interaction between temperature treatment and pyraclostrobin concentration on H. azteca mortality, body length, and dry mass under direct aqueous exposure conditions. In an indirect exposure scenario in which only leaf material was exposed to pyraclostrobin, H. azteca did not preferentially feed on or avoid treated leaf disks compared to controls. This study describes the influence of realistic temperature variation on fungicide toxicity to shredding invertebrates, which is important for understanding how future alterations in daily temperature regimes due to climate change may influence the assessment of ecological risk of contaminants in aquatic ecosystems. Copyright © 2016. Published by Elsevier Ltd.

Effects of temperature and velocity of droplet ejection process of simulated nanojets onto a moving plate's surface

International Nuclear Information System (INIS)

Fang, T.-H.; Chang, W.-J.; Lin, S.-L.

2006-01-01

This paper uses molecular dynamics simulation based on the Lennard-Jones potential to study the effects that temperature and velocity have on, the nanojet droplet ejection process, when the droplet is ejected at an angle onto a moving plate's surface. According to the analysis, it was found that the width of the spreading droplet increased as the temperature and the time were increased. Also found was an energy wave phenomenon. The contact angle of the droplet deposited on the plate decreased as the temperature was increased. Furthermore, the layer phenomena became apparent when the atoms were deposited on a moving plate. Thinner film layers were obtained as the velocity of the moving plate was increased. The contact angle on the left side of the droplet was larger than that on the right side when the plate was moving from right to left

Recent progress in the melt-process technique of high-temperature superconductors

CERN Document Server

Ikuta, H; Mizutani, U

1999-01-01

Recently, the performance of high-temperature super conductors prepared by the melt-process technique has been greatly improved. This progress was accomplished by the addition of Ag into the starting materials of the Sm-Ba-CuO $9 system, which prevents the formation of severe macro-sized cracks in the finished samples. The magnetic flux density trapped by this material has now reached 9 T at 25 K, which is comparable to the magnetic flux density produced by $9 ordinary superconducting magnets. The amount of magnetic flux density that can be trapped by the sample is limited by the mechanical strength rather than superconducting properties of the material. The increase in the mechanical $9 strength of the material is important both for further improvement of the material properties and for ensuring reliability of the material in practical applications. (20 refs).

High temperature, short time pasteurization temperatures inversely affect bacterial numbers during refrigerated storage of pasteurized fluid milk.

Science.gov (United States)

Ranieri, M L; Huck, J R; Sonnen, M; Barbano, D M; Boor, K J

2009-10-01

The grade A Pasteurized Milk Ordinance specifies minimum processing conditions of 72 degrees C for at least 15 s for high temperature, short time (HTST) pasteurized milk products. Currently, many US milk-processing plants exceed these minimum requirements for fluid milk products. To test the effect of pasteurization temperatures on bacterial numbers in HTST pasteurized milk, 2% fat raw milk was heated to 60 degrees C, homogenized, and treated for 25 s at 1 of 4 different temperatures (72.9, 77.2, 79.9, or 85.2 degrees C) and then held at 6 degrees C for 21 d. Aerobic plate counts were monitored in pasteurized milk samples at d 1, 7, 14, and 21 postprocessing. Bacterial numbers in milk processed at 72.9 degrees C were lower than in milk processed at 85.2 degrees C on each sampling day, indicating that HTST fluid milk-processing temperatures significantly affected bacterial numbers in fluid milk. To assess the microbial ecology of the different milk samples during refrigerated storage, a total of 490 psychrotolerant endospore-forming bacteria were identified using DNA sequence-based subtyping methods. Regardless of processing temperature, >85% of the isolates characterized at d 0, 1, and 7 postprocessing were of the genus Bacillus, whereas more than 92% of isolates characterized at d 14 and 21 postprocessing were of the genus Paenibacillus, indicating that the predominant genera present in HTST-processed milk shifted from Bacillus spp. to Paenibacillus spp. during refrigerated storage. In summary, 1) HTST processing temperatures affected bacterial numbers in refrigerated milk, with higher bacterial numbers in milk processed at higher temperatures; 2) no significant association was observed between genus isolated and pasteurization temperature, suggesting that the genera were not differentially affected by the different processing temperatures; and 3) although typically present at low numbers in raw milk, Paenibacillus spp. are capable of growing to numbers that can

Effect of the Reduction Temperature of PdAg Nanoparticles during the Polyol Process in the Ethanol Electrooxidation Reaction

Directory of Open Access Journals (Sweden)

R. Carrera-Cerritos

2018-01-01

Full Text Available This work reports the effect of reduction temperature during the synthesis of PdAg catalysts through the polyol process and their evaluation in the ethanol electrooxidation reaction (EOR. The characterization was performed using Transmission Electron Microscopy (TEM and X-Ray Diffraction (XRD. The electrochemical evaluation for the ethanol electrooxidation reaction was implemented in alkaline medium using chronoamperometry (CA and cyclic voltammetry (CV. An important effect of the reduction temperature on electroactivity and catalytic stability was observed: both the maximum current density and the catalytic stability were higher in the catalyst synthesized at the highest temperature (135°C. This performance was associated with the extent of the interaction between Pd and Ag which was measured in terms of the structural expansion of Pd.

Process Developed for Generating Ceramic Interconnects With Low Sintering Temperatures for Solid Oxide Fuel Cells

Science.gov (United States)

Zhong, Zhi-Min; Goldsby, Jon C.

2005-01-01

Solid oxide fuel cells (SOFCs) have been considered as premium future power generation devices because they have demonstrated high energy-conversion efficiency, high power density, and extremely low pollution, and have the flexibility of using hydrocarbon fuel. The Solid-State Energy Conversion Alliance (SECA) initiative, supported by the U.S. Department of Energy and private industries, is leading the development and commercialization of SOFCs for low-cost stationary and automotive markets. The targeted power density for the initiative is rather low, so that the SECA SOFC can be operated at a relatively low temperature (approx. 700 C) and inexpensive metallic interconnects can be utilized in the SOFC stack. As only NASA can, the agency is investigating SOFCs for aerospace applications. Considerable high power density is required for the applications. As a result, the NASA SOFC will be operated at a high temperature (approx. 900 C) and ceramic interconnects will be employed. Lanthanum chromite-based materials have emerged as a leading candidate for the ceramic interconnects. The interconnects are expected to co-sinter with zirconia electrolyte to mitigate the interface electric resistance and to simplify the processing procedure. Lanthanum chromites made by the traditional method are sintered at 1500 C or above. They react with zirconia electrolytes (which typically sinter between 1300 and 1400 C) at the sintering temperature of lanthanum chromites. It has been envisioned that lanthanum chromites with lower sintering temperatures can be co-fired with zirconia electrolyte. Nonstoichiometric lanthanum chromites can be sintered at lower temperatures, but they are unstable and react with zirconia electrolyte during co-sintering. NASA Glenn Research Center s Ceramics Branch investigated a glycine nitrate process to generate fine powder of the lanthanum-chromite-based materials. By simultaneously doping calcium on the lanthanum site, and cobalt and aluminum on the

Development of a versatile high-temperature short-time (HTST) pasteurization device for small-scale processing of cell culture medium formulations.

Science.gov (United States)

Floris, Patrick; Curtin, Sean; Kaisermayer, Christian; Lindeberg, Anna; Bones, Jonathan

2018-07-01

The compatibility of CHO cell culture medium formulations with all stages of the bioprocess must be evaluated through small-scale studies prior to scale-up for commercial manufacturing operations. Here, we describe the development of a bespoke small-scale device for assessing the compatibility of culture media with a widely implemented upstream viral clearance strategy, high-temperature short-time (HTST) treatment. The thermal stability of undefined medium formulations supplemented with soy hydrolysates was evaluated upon variations in critical HTST processing parameters, namely, holding times and temperatures. Prolonged holding times of 43 s at temperatures of 110 °C did not adversely impact medium quality while significant degradation was observed upon treatment at elevated temperatures (200 °C) for shorter time periods (11 s). The performance of the device was benchmarked against a commercially available mini-pilot HTST system upon treatment of identical formulations on both platforms. Processed medium samples were analyzed by untargeted LC-MS/MS for compositional profiling followed by chemometric evaluation, which confirmed the observed degradation effects caused by elevated holding temperatures but revealed comparable performance of our developed device with the commercial mini-pilot setup. The developed device can assist medium optimization activities by reducing volume requirements relative to commercially available mini-pilot instrumentation and by facilitating fast throughput evaluation of heat-induced effects on multiple medium lots.

High Temperature Reactors for a proposed IAEA Coordinated Research Project on Energy Neutral Mineral Development Processes

International Nuclear Information System (INIS)

Haneklaus, Nils; Reitsma, Frederik; Tulsidas, Harikrishnan

2014-01-01

The International Atomic Energy Agency (IAEA) is promoting a new Coordinated Research Project (CRP) to elaborate on the applicability and potential of using High Temperature Reactors (HTRs) to provide process heat and/or electricity to power energy intensive mineral development processes. The CRP aims to provide a platform for cooperation between HTR-developers and mineral development processing experts. Energy intensive mineral development processes with (e.g. phosphate-, gold-, copper-, rare earth ores) or without (e.g. titanium-, aluminum ore) the possibility to recover accompanying uranium and/or thorium that could be developed and used to run the HTR for “energy neutral” processing of the primary ore shall be discussed according to the participants needs. This paper specifically focuses on the aspects that need to be addressed by HTR-designers and developers. First requirements that should be fulfilled by the HTR-designs are highlighted together with the desired outcomes of the research project. (author)

Effect of calcination temperature on the crystallite growth of cerium oxide nano-powders prepared by the co-precipitation process

Energy Technology Data Exchange (ETDEWEB)

Chen, Jian-Chih [Department of Orthopaedics, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); Chen, Wen-Cheng [School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Tien, Yin-Chun [Department of Orthopaedics, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); Shih, Chi-Jen, E-mail: cjshih@kmu.edu.t [Department of Fragrance and Cosmetics Science, Kaohsiung Medical University, 100 Shi-Chuan1st Road, Kaohsiung 80708, Taiwan (China)

2010-04-30

Cerium oxide nanocrystallites were synthesized by a co-precipitation process at a relatively low temperature, using cerium (III) nitrate as the starting material in a water solution with pH in the range of 8-9. The effect of calcination temperature on the crystallite growth of cerium oxide nano-powders was investigated by X-ray diffraction, transmission electron microscopy and electron diffraction. The crystallization temperature of the cerium oxide powders was estimated to be about 273 K, by XRD analysis. When calcined at temperatures from 473 to 1273 K, face-centered cubic phase crystallization was observed by XRD. The crystallite size of the cerium oxide increased from 12.0 to 48 nm as the calcining temperature increased from 473 to 1273 K, in the pH range 8-9. The activation energy for the growth of cerium oxide nanoparticles was found to have very low values of 17.5 kJ/mol for pH = 8 and 16.0 kJ/mol for pH = 9.

Combined modified atmosphere packaging and low temperature storage delay lignification and improve the defense response of minimally processed water bamboo shoot.

Science.gov (United States)

Song, Lili; Chen, Hangjun; Gao, Haiyan; Fang, Xiangjun; Mu, Honglei; Yuan, Ya; Yang, Qian; Jiang, Yueming

2013-09-04

Minimally processed water bamboo shoot (WBS) lignifies and deteriorates rapidly at room temperature, which limits greatly its marketability. This study was to investigate the effect of modified atmosphere packaging (MAP) on the sensory quality index, lignin formation, production of radical oxygen species (ROS) and activities of scavenging enzymes, membrane integrity and energy status of minimally processed WBS when packaged with or without the sealed low-density polyethylene (LDPE) bags, and then stored at 20°C for 9 days or 2°C for 60 days. The sensory quality of minimally processed WBS decreased quickly after 6 days of storage at 20°C. Low temperature storage maintained a higher sensory quality index within the first 30 days, but exhibited higher contents of lignin and hydrogen peroxide (H2O2) as compared with non-MAP shoots at 20°C. Combined MAP and low temperature storage not only maintained good sensory quality after 30 days, but also reduced significantly the increases in lignin content, superoxide anion (O2.-) production rate, H2O2 content and membrane permeability, maintained high activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), and reduced the increase in activities of lipase, phospholipase D (PLD) and lipoxygenase (LOX). Furthermore, the minimally processed WBS under MAP condition exhibited higher energy charge (EC) and lower adenosine monophosphate (AMP) content by the end of storage (60 days) at 2°C than those without MAP or stored for 9 days at 20°C. These results indicated that MAP in combination with low temperature storage reduced lignification of minimally processed WBS, which was closely associated with maintenance of energy status and enhanced activities of antioxidant enzymes, as well as reduced alleviation of membrane damage caused by ROS.

P-type Cu2O/SnO bilayer thin film transistors processed at low temperatures

KAUST Repository

Al-Jawhari, Hala A.

2013-10-09

P-type Cu2O/SnO bilayer thin film transistors (TFTs) with tunable performance were fabricated using room temperature sputtered copper and tin oxides. Using Cu2O film as capping layer on top of a SnO film to control its stoichiometry, we have optimized the performance of the resulting bilayer transistor. A transistor with 10 nm/15 nm Cu2O to SnO thickness ratio (25 nm total thickness) showed the best performance using a maximum process temperature of 170 C. The bilayer transistor exhibited p-type behavior with field-effect mobility, on-to-off current ratio, and threshold voltage of 0.66 cm2 V-1 s-1, 1.5×10 2, and -5.2 V, respectively. The advantages of the bilayer structure relative to single layer transistor are discussed. © 2013 American Chemical Society.

Designing for elevated temperature

International Nuclear Information System (INIS)

Boer, G.A. de

1982-01-01

The reasons for the application of higher process temperatures are explained. The properties of stainless steel are compared with those of other materials such as molybdenum. Factors influencing the choice of the material such as availability of material data at high temperature, controllability, and strength of heat-affected zone are discussed. The process of designing a structure for safe and economic high-temperature application is outlined: design-by-analysis in contrast to the design-by-rule which is general practice for low-temperature applications. The rules laid down in the ASME Pressure Vessel Code Case N47 are explained as well as the procedure for inelastic stress calculations. (author)

Fabrication and Characterization of 3D-Printed Highly-Porous 3D LiFePO₄ Electrodes by Low Temperature Direct Writing Process.

Science.gov (United States)

Liu, Changyong; Cheng, Xingxing; Li, Bohan; Chen, Zhangwei; Mi, Shengli; Lao, Changshi

2017-08-10

LiFePO₄ (LFP) is a promising cathode material for lithium-ion batteries. In this study, low temperature direct writing (LTDW)-based 3D printing was used to fabricate three-dimensional (3D) LFP electrodes for the first time. LFP inks were deposited into a low temperature chamber and solidified to maintain the shape and mechanical integrity of the printed features. The printed LFP electrodes were then freeze-dried to remove the solvents so that highly-porous architectures in the electrodes were obtained. LFP inks capable of freezing at low temperature was developed by adding 1,4 dioxane as a freezing agent. The rheological behavior of the prepared LFP inks was measured and appropriate compositions and ratios were selected. A LTDW machine was developed to print the electrodes. The printing parameters were optimized and the printing accuracy was characterized. Results showed that LTDW can effectively maintain the shape and mechanical integrity during the printing process. The microstructure, pore size and distribution of the printed LFP electrodes was characterized. In comparison with conventional room temperature direct ink writing process, improved pore volume and porosity can be obtained using the LTDW process. The electrochemical performance of LTDW-fabricated LFP electrodes and conventional roller-coated electrodes were conducted and compared. Results showed that the porous structure that existed in the printed electrodes can greatly improve the rate performance of LFP electrodes.

Temperature Pill

Science.gov (United States)

1988-01-01

Ingestible Thermal Monitoring System was developed at Johns Hopkins University as means of getting internal temperature readings for treatments of such emergency conditions as dangerously low (hypothermia) and dangerously high (hyperthermia) body temperatures. ITMS's accuracy is off no more than one hundredth of a degree and provides the only means of obtaining deep body temperature. System has additional applicability in fertility monitoring and some aspects of surgery, critical care obstetrics, metabolic disease treatment, gerontology (aging) and food processing research. Three-quarter inch silicone capsule contains telemetry system, micro battery, and a quartz crystal temperature sensor inserted vaginally, rectally, or swallowed.

Deep Drawing for high LDR by a new Hydro-rim Forming Process with Differential Temperature- Analysis and Experiments

International Nuclear Information System (INIS)

Simon, Y. Ben; Tirosh, J.; Rubinski, Ludmila

2005-01-01

The purpose of this study is to analyze and test a possible increase of the Limit Drawing Ratio (LDR) in Deep Drawing by Hydro-rim process (a certain subset of the classical Hydroforming) which includes the newly differential temperature effect. The idea is to facilitate the plastic flow by local heating along the flange and to cool the area where strength is needed. The suggested analysis is based on the dual bounds approach (upper and lower bounds simultaneously) using the highly versatile Johnson-Cook constitutive material model. The advantage of combined high hydraulic pressure (about 1000 bar) with relatively high blank temperature (with magnitude of about one third the melting temperature of the considered material) in the same operation is discussed. Emphasis is given to the rule of blank temperature difference (between the flange and the wall of the product) conjugate with optimal hydro rim pressure in increasing the limit drawing ratio of the products (Aluminum, Copper and various Steels)

Methods for efficient usage of energy and materials in high temperature metallurgical processes; Methoden zur Energie- und Stoffeffizienz in der metallurgischen Hochtemperaturtechnik

Energy Technology Data Exchange (ETDEWEB)

Scholz, Reinhard; Stuermer, Thomas [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. fuer Energieverfahrenstechnik

2012-07-15

Metallurgy belongs to the most energy intensive industries where the chain of processes, from materials production to materials recycling, proceeds typically at high temperatures. The higher the process temperature, the more valuable is energy recovery. In parallel with the current trends of improving energy efficiencies, one observes an increase of energy conversion costs in conversion processes of both fossil fuels and renewable energy sources. The paper is concerned with methods of improving energy efficiencies, as well as, with establishing their maximum values determined by the thermodynamics of the metallurgical processes considered. In a number of processes, for example in the blast furnace process of pig iron production, these thermodynamic limits have been reached. Then, if the prices of raw materials and/or energy (electricity produced either from fossil fuels or from renewables) are on the rise, the industry does not have any other option but increasing the final product prices which obviously affect competitiveness. (orig.)

High-Temperature-Short-Time Annealing Process for High-Performance Large-Area Perovskite Solar Cells.

Science.gov (United States)

Kim, Minjin; Kim, Gi-Hwan; Oh, Kyoung Suk; Jo, Yimhyun; Yoon, Hyun; Kim, Ka-Hyun; Lee, Heon; Kim, Jin Young; Kim, Dong Suk

2017-06-27

Organic-inorganic hybrid metal halide perovskite solar cells (PSCs) are attracting tremendous research interest due to their high solar-to-electric power conversion efficiency with a high possibility of cost-effective fabrication and certified power conversion efficiency now exceeding 22%. Although many effective methods for their application have been developed over the past decade, their practical transition to large-size devices has been restricted by difficulties in achieving high performance. Here we report on the development of a simple and cost-effective production method with high-temperature and short-time annealing processing to obtain uniform, smooth, and large-size grain domains of perovskite films over large areas. With high-temperature short-time annealing at 400 °C for 4 s, the perovskite film with an average domain size of 1 μm was obtained, which resulted in fast solvent evaporation. Solar cells fabricated using this processing technique had a maximum power conversion efficiency exceeding 20% over a 0.1 cm 2 active area and 18% over a 1 cm 2 active area. We believe our approach will enable the realization of highly efficient large-area PCSs for practical development with a very simple and short-time procedure. This simple method should lead the field toward the fabrication of uniform large-scale perovskite films, which are necessary for the production of high-efficiency solar cells that may also be applicable to several other material systems for more widespread practical deployment.

The nitrate to ammonia and ceramic (NAC) process: A newly developed low-temperature technology

International Nuclear Information System (INIS)

Mattus, A.J.; Lee, D.D.

1993-01-01

Bench-top feasibility studies with Hanford single-shell tank (SST) simulants, using a new low-temperature (50-60 degrees C) process for converting nitrate to ammonia and ceramic, have conclusively shown that between 90 and 99% of the nitrate at Hanford can be readily converted to ammonia. In this process, aluminum powders or shot can be used to convert alkaline, nitrate-based supernate to ammonia and an alumina-silica-based ceramic solid. The process may actually be able to utilize already contaminated aluminum scrap metal from various US DOE sites to effect the conversion. The final nitrate-free ceramic product can be calcined, pressed, and sintered like any other ceramic. Based upon the starting volumes of 6.2 and 3.1 M sodium nitrate solution (probable supernate concentrations resulting from salt-cake/sludge removal from the Hanford SSTs), volume reductions as high as 70% are currently obtained, compared with an expected 40 to 50% volume increase if the Hanford supernate were grouted. Engineering data extracted from bench-top studies indicate that the process will be very economical. These data were used to cost a batch facility with a production rate of 1200 kilograms of nitrate per hour for processing all the Hanford SST waste over 20 years. Our process cost analysis indicates that between $2.01 and 2.66 will be required to convert each kilogram of nitrate. Based upon 1957 literature, these costs are one-third to one-half of the processing costs quoted for electrolytic and thermal processes

The effect of coiling temperature on the microstructure and mechanical properties of a niobium–titanium microalloyed steel processed via thin slab casting

International Nuclear Information System (INIS)

Challa, V.S.A.; Zhou, W.H.; Misra, R.D.K.; O'Malley, R.; Jansto, S.G.

2014-01-01

We describe here the influence of coiling temperature on the microstructure and mechanical properties, especially toughness, in a low carbon niobium microalloyed steel processed via thin slab casting. The objective is to elucidate the impact of coiling temperature on the nature and distribution of microstructural constituents (including different phases, precipitates, and dislocations) that contribute to variation in the strength–toughness relationship of these steels. In general, the microstructure primarily consisted of fine lath-type bainite and polygonal ferrite, and NbC, TiC and (Nb, Ti)C precipitates of size ∼2–10 nm in the matrix and at dislocations. However, the dominance of bainite and distribution of precipitates was a function of coiling temperature. The lower coiling temperature provided superior strength–toughness combination and is attributed to predominantly bainitic microstructure and uniform precipitation of NbC, TiC, and (Nb, Ti)C during the coiling process, consistent with continuous cooling transformation diagrams

The effect of coiling temperature on the microstructure and mechanical properties of a niobium–titanium microalloyed steel processed via thin slab casting

Energy Technology Data Exchange (ETDEWEB)

Challa, V.S.A.; Zhou, W.H. [Laboratory for Excellence in Advanced Steel Research, Center for Structural and Functional Materials, Institute for Material Research and Innovation, University of Louisiana at Lafayette, P.O. Box 44130, Lafayette, LA 70503 (United States); Misra, R.D.K., E-mail: dmisra@louisiana.edu [Laboratory for Excellence in Advanced Steel Research, Center for Structural and Functional Materials, Institute for Material Research and Innovation, University of Louisiana at Lafayette, P.O. Box 44130, Lafayette, LA 70503 (United States); O' Malley, R. [Nucor Decatur Sheet Mill, 4301 Iverson Blvd., Trinity, AL 35673 (United States); Jansto, S.G. [CBMM North America, 1000 Old Pond Road, Bridgeville, PA 15017 (United States)

2014-02-10

We describe here the influence of coiling temperature on the microstructure and mechanical properties, especially toughness, in a low carbon niobium microalloyed steel processed via thin slab casting. The objective is to elucidate the impact of coiling temperature on the nature and distribution of microstructural constituents (including different phases, precipitates, and dislocations) that contribute to variation in the strength–toughness relationship of these steels. In general, the microstructure primarily consisted of fine lath-type bainite and polygonal ferrite, and NbC, TiC and (Nb, Ti)C precipitates of size ∼2–10 nm in the matrix and at dislocations. However, the dominance of bainite and distribution of precipitates was a function of coiling temperature. The lower coiling temperature provided superior strength–toughness combination and is attributed to predominantly bainitic microstructure and uniform precipitation of NbC, TiC, and (Nb, Ti)C during the coiling process, consistent with continuous cooling transformation diagrams.

Hydrophilic Graphene Preparation from Gallic Acid Modified Graphene Oxide in Magnesium Self-Propagating High Temperature Synthesis Process

Science.gov (United States)

Cao, Lei; Li, Zhenhuan; Su, Kunmei; Cheng, Bowen

2016-10-01

Hydrophilic graphene sheets were synthesized from a mixture of magnesium and gallic acid (GA) modified graphene oxide (GO) in a self-propagating high-temperature synthesis (SHS) process, and hydrophilic graphene sheets displayed the higher C/O ratio (16.36), outstanding conductivity (~88900 S/m) and excellent water-solubility. GO sheets were connected together by GA, and GA was captured to darn GO structure defects through the formation of hydrogen bonds and ester bonds. In SHS process, the most oxygen ions of GO reacted with magnesium to prevent the escape of carbon dioxide and carbon monoxide to from the structure defects associated with vacancies, and GA could take place the high-temperature carbonization, during which a large-area graphene sheets formed with a part of the structure defects being repaired. When only GO was reduced by magnesium in SHS process, and the reduced GO (rGO) exhibited the smaller sheets, the lower C/O ratio (15.26), the weaker conductivity (4200 S/m) and the poor water-solubility because rGO inevitably left behind carbon vacancies and topological defects. Therefore, the larger sheet, less edge defects and free structure defects associated with vacancies play a key role for graphene sheets good dispersion in water.

Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

Science.gov (United States)

Cox, Sarah B.; Lui, Donovan; Wang, Xin; Gou, Jihua

2014-01-01

The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000 deg C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200 deg C, Beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing.

Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

Science.gov (United States)

Cox, Sarah B.; Lui, Donovan; Gou, Jihua

2014-01-01

The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200C, beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing.

High critical temperature superconducting composite and fabrication process

International Nuclear Information System (INIS)

Dubots, P.; Legat, D.

1989-01-01

The core comprises a high temperature superconducting sintered oxide coated with alumina or barium oxide covered with a first sheath in aluminum, a second sheath in niobium and a third sheath in copper [fr

Characterization and photoactivity of Pt/N-doped TiO{sub 2} synthesized through a sol–gel process at room temperature

Energy Technology Data Exchange (ETDEWEB)

Huang, Bing-Shun [Feng Chia University, Green Energy Development Center (China); Tseng, Hui-Hsin [Chung Shan Medical University, School of Occupational Safety and Health (China); Su, En-Chin; Chiu, I-Ching; Wey, Ming-Yen, E-mail: mywey@dragon.nchu.edu.tw [National Chung Hsing University, Department of Environmental Engineering (China)

2015-07-15

The rates of photocatalytic production of H{sub 2} by Pt/N-doped TiO{sub 2} are significantly affected by the hydrolysis temperature applied during the sol–gel process. Production rates increase as the hydrolysis temperature decreases from 40 to 20 °C. The effects of the hydrolysis temperature on the properties and water-splitting behavior of photocatalysts were investigated. Characterization results showed that hydrolysis temperatures higher than 40 °C induce the formation of the rutile phase and particle agglomeration, reduce the N-dopant content, and decrease the range of visible-light absorption. In this study, a low hydrolysis temperature of about 20 °C is optimal for the sol–gel preparation of N-doped TiO{sub 2}; this temperature favors the formation of high-purity anatase, small particle size, extensive visible-light absorption, and excellent rates of photocatalytic production of H{sub 2} (about 2100 μmol h{sup −1} g{sup −1})

Multi-field coupling finite element analysis for determining the influence of temperature field on die service life during precision-forming process of steel synchronizer ring

International Nuclear Information System (INIS)

Zhao, Jun; Luo, Shan-Ming; Li, Feng-Qiang; Xu, Chen-Bing

2017-01-01

Failure analysis shows that increased die temperature caused by severe plastic deformation of material and heat conduction between hot billet and cavity significantly affects the distortion of gear cavity in steel synchronizer ring forging process. The forging process of steel synchronizer ring and die temperature distribution under different forging conditions are analyzed through finite element method. Simulation results show that severe plastic deformation occurs in the gear cavity. The improvement of lubrication condition results in decreased die temperature. When the initial billet temperature is high, the die temperature is also high. Increasing forging speed in a certain range facilitates the die temperature decrease. The distribution of die temperature in synthetic forming technology is more reasonable than that of one step forging. The synthetic forming technology is adopted in production to reduce the effects of severe plastic deformation caused by die temperature. The ejection mechanism and control system of the double disc friction press are improved to reduce the contact time between the hot billet and cavity. Experimental results show that synthetic forming technology is reasonable, and that the die service life is prolonged.

Multi-field coupling finite element analysis for determining the influence of temperature field on die service life during precision-forming process of steel synchronizer ring

Energy Technology Data Exchange (ETDEWEB)

Zhao, Jun; Luo, Shan-Ming; Li, Feng-Qiang; Xu, Chen-Bing [Xiamen University of Technology, Xiamen (China)

2017-07-15

Failure analysis shows that increased die temperature caused by severe plastic deformation of material and heat conduction between hot billet and cavity significantly affects the distortion of gear cavity in steel synchronizer ring forging process. The forging process of steel synchronizer ring and die temperature distribution under different forging conditions are analyzed through finite element method. Simulation results show that severe plastic deformation occurs in the gear cavity. The improvement of lubrication condition results in decreased die temperature. When the initial billet temperature is high, the die temperature is also high. Increasing forging speed in a certain range facilitates the die temperature decrease. The distribution of die temperature in synthetic forming technology is more reasonable than that of one step forging. The synthetic forming technology is adopted in production to reduce the effects of severe plastic deformation caused by die temperature. The ejection mechanism and control system of the double disc friction press are improved to reduce the contact time between the hot billet and cavity. Experimental results show that synthetic forming technology is reasonable, and that the die service life is prolonged.

Deformation and Phase Transformation Processes in Polycrystalline NiTi and NiTiHf High Temperature Shape Memory Alloys

Science.gov (United States)

Benafan, Othmane

2012-01-01

The deformation and transformation mechanisms of polycrystalline Ni49.9Ti50.1 and Ni50.3Ti29.7Hf20 (in at.%) shape memory alloys were investigated by combined experimental and modeling efforts aided by an in situ neutron diffraction technique at stress and temperature. The thermomechanical response of the low temperature martensite, the high temperature austenite phases, and changes between these two states during thermomechanical cycling were probed and reported. In the cubic austenite phase, stress-induced martensite, deformation twinning and slip processes were observed which helped in constructing a deformation map that contained the limits over which each of the identified mechanisms was dominant. Deformation of the monoclinic martensitic phase was also investigated where the microstructural changes (texture, lattice strains, and phase fractions) during room-temperature deformation and subsequent thermal cycling were compared to the bulk macroscopic response. When cycling between these two phases, the evolution of inelastic strains, along with the shape setting procedures were examined and used for the optimization of the transformation properties as a function of deformation levels and temperatures. Finally, this work was extended to the development of multiaxial capabilities at elevated temperatures for the in situ neutron diffraction measurements of shape memory alloys on the VULCAN Diffractometer at Oak Ridge National Laboratory.

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.

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.

The microbial community in a high-temperature enhanced biological phosphorus removal (EBPR process

Directory of Open Access Journals (Sweden)

Ying Hui Ong

2016-01-01

Full Text Available An enhanced biological phosphorus removal (EBPR process operated at a relatively high temperature, 28 °C, removed 85% carbon and 99% phosphorus from wastewater over a period of two years. This study investigated its microbial community through fluorescent in situ hybridization (FISH and clone library generation. Through FISH, considerably more Candidatus “Accumulibacter phosphatis” (Accumulibacter-polyphosphate accumulating organisms (PAOs than Candidatus ‘Competibacter phosphatis’ (Competibacter-glycogen accumulating organisms were detected in the reactor, at 36 and 7% of total bacterial population, respectively. A low ratio of Glycogen/Volatile Fatty Acid of 0.69 further indicated the dominance of PAOs in the reactor. From clone library generated, 26 operational taxonomy units were retrieved from the sludge and a diverse population was shown, comprising Proteobacteria (69.6%, Actinobacteria (13.7%, Bacteroidetes (9.8%, Firmicutes (2.94%, Planctomycetes (1.96%, and Acidobacteria (1.47%. Accumulibacter are the only recognized PAOs revealed by the clone library. Both the clone library and FISH results strongly suggest that Accumulibacter are the major PAOs responsible for the phosphorus removal in this long-term EBPR at relatively high temperature.

Indium oxide octahedrons based on sol–gel process enhance room temperature gas sensing performance

Energy Technology Data Exchange (ETDEWEB)

Mu, Xiaohui [Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, Shandong (China); Chen, Changlong, E-mail: chem.chencl@hotmail.com [Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, Shandong (China); Han, Liuyuan [Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, Shandong (China); Shao, Baiqi [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Wei, Yuling [Instrumental Analysis Center, Qilu University of Technology, Jinan 250353, Shandong (China); Liu, Qinglong; Zhu, Peihua [Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, Shandong (China)

2015-07-15

Highlights: • In{sub 2}O{sub 3} octahedron films are prepared based on sol–gel technique for the first time. • The preparation possesses merits of low temperature, catalyst-free and large production. • It was found that the spin-coating process in film fabrication was key to achieve the octahedrons. • The In{sub 2}O{sub 3} octahedrons could significantly enhance room temperature NO{sub 2} gas sensing performance. - Abstract: Indium oxide octahedrons were prepared on glass substrates through a mild route based on sol–gel technique. The preparation possesses characteristics including low temperature, catalyst-free and large production, which is much distinguished from the chemical-vapor-deposition based methods that usually applied to prepare indium oxide octahedrons. Detailed characterization revealed that the indium oxide octahedrons were single crystalline, with {1 1 1} crystal facets exposed. It was found that the spin-coating technique was key for achieving the indium oxide crystals with octahedron morphology. The probable formation mechanism of the indium oxide octahedrons was proposed based on the experiment results. Room temperature NO{sub 2} gas sensing measurements exhibited that the indium oxide octahedrons could significantly enhance the sensing performance in comparison with the plate-like indium oxide particles that prepared from the dip-coated gel films, which was attributed to the abundant sharp edges and tips as well as the special {1 1 1} crystal facets exposed that the former possessed. Such a simple wet-chemical based method to prepare indium oxide octahedrons with large-scale production is promising to provide the advanced materials that can be applied in wide fields like gas sensing, solar energy conversion, field emission, and so on.

Indium oxide octahedrons based on sol–gel process enhance room temperature gas sensing performance

International Nuclear Information System (INIS)

Mu, Xiaohui; Chen, Changlong; Han, Liuyuan; Shao, Baiqi; Wei, Yuling; Liu, Qinglong; Zhu, Peihua

2015-01-01

Highlights: • In 2 O 3 octahedron films are prepared based on sol–gel technique for the first time. • The preparation possesses merits of low temperature, catalyst-free and large production. • It was found that the spin-coating process in film fabrication was key to achieve the octahedrons. • The In 2 O 3 octahedrons could significantly enhance room temperature NO 2 gas sensing performance. - Abstract: Indium oxide octahedrons were prepared on glass substrates through a mild route based on sol–gel technique. The preparation possesses characteristics including low temperature, catalyst-free and large production, which is much distinguished from the chemical-vapor-deposition based methods that usually applied to prepare indium oxide octahedrons. Detailed characterization revealed that the indium oxide octahedrons were single crystalline, with {1 1 1} crystal facets exposed. It was found that the spin-coating technique was key for achieving the indium oxide crystals with octahedron morphology. The probable formation mechanism of the indium oxide octahedrons was proposed based on the experiment results. Room temperature NO 2 gas sensing measurements exhibited that the indium oxide octahedrons could significantly enhance the sensing performance in comparison with the plate-like indium oxide particles that prepared from the dip-coated gel films, which was attributed to the abundant sharp edges and tips as well as the special {1 1 1} crystal facets exposed that the former possessed. Such a simple wet-chemical based method to prepare indium oxide octahedrons with large-scale production is promising to provide the advanced materials that can be applied in wide fields like gas sensing, solar energy conversion, field emission, and so on

VARTM Processing of High Temperature Polymer Matrix Composites

National Research Council Canada - National Science Library

Criss, Jr, Jim M

2008-01-01

The overall technical objective of the Phase 1 effort was to extend and advance the state the-art in high temperature composite fabrication techniques by developing a High Tempera Vacuum Assisted Resin Transfer Molding (VARTM...

Evaluation of limiting factors affecting photovoltaic performance of low-temperature-processed TiO₂ films in dye-sensitized solar cells.

Science.gov (United States)

Lee, Taek-Yong; Kim, Hui-Seon; Park, Nam-Gyu

2014-04-14

Limiting factors affecting photovoltaic performance of dye-sensitized solar cell employing low-temperature-processed TiO2 films were investigated. TiO2 films were prepared at a low temperature of 200 °C using the normal alcohol-containing binder-free TiO2 paste (LT200). Their photovoltaic performance was compared to a high-temperature (550 °C) annealed TiO2 film prepared using a polymer binder containing TiO2 paste (HT550). Compared to the proportional increase in conversion efficiency with TiO2 film thickness upto 14 μm for HT550, the increase in efficiency was terminated at relatively smaller thickness of about 8 μm for LT200 mainly due to unaugmented photocurrent. From the transient photocurrent-voltage studies, the electron transport rate was found to be almost identical, while charge recombination was one order of magnitude faster for LT200. Consequently, the electron diffusion length was more than 2-3 times shorter for LT200 than for HT550. Electron diffusion length and electron life time obtained from electrochemical impedance analysis were well consistent with those observed from transient measurement. Density of states (DOS) was evaluated to be shallow and narrow in LT200, which was responsible for limiting photovoltaic performance in the low-temperature processed TiO2 film. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.