PERFORMA NEUTRONIK BAHAN BAKAR LiF-BeF2-ThF4-UF4 PADA SMALL MOBILE-MOLTEN SALT REACTOR

Directory of Open Access Journals (Sweden)

S. N. Rokhman

2015-04-01

Full Text Available Telah dilakukan analisis terhadap performa neutronik bahan bakar garam lebur LiF-BeF2-ThF4-UF4 pada Small Mobile-Molten Salt Reactor (SM-MSR. Penyesuaian konfigurasi teras dan temperatur operasi harus dilakukan untuk penggunaan bahan bakar baru tersebut agar mencapai keff > 1 dan CR (conversion ratio > 1 pada fraksi 0,5% 233U, 20% 232Th, 28% Li, 51,5% Be. Setelah didapat nilai keff ≈ 1 dan CR ≈ 1, dilakukan analisis pengaruh perubahan Th terhadap Be dan Be terhadap Li yang terlihat dalam perubahan parameter keff dan CR. Setelah itu fraksi 233U divariasi antara 0,5–0,46% untuk memperoleh keff > 1 dan CR > 1. Dalam perhitungan koefisien reaktifitas temperatur (αT, temperatur teras dinaikkan sebesar +25K dan +50K., dan untuk koefisien reaktifitas void (αV, densitas bahan bakar dikurangi hingga 90%. Hasil perhitungan menunjukkan bahwa pengurangan Th terhadap Be menyebabkan penurunan nilai CR dan naiknya keff akibat berkurangnya material fertil. Sebaliknya penambahan Be terhadap Li mengakibatkan terjadi kenaikan nilai keff dan menurunkan CR, akibat laju serapan Li lebih besar dari Be. Pada 5 (lima fraksi 233U dalam rentang 0,5–0,49%, hasil perhitungan keff dan CR masing-masing bervariasi dalam rentang 1,00001 - 1,00327 dan 1,00016 - 1,00731. Untuk faktor puncak daya (PPF, hasil perhitungan memberikan nilai dalam rentang 2,4311 -2,4714. Sedangkan untuk parameter keselamatan, koefisien reaktivitas temperatur (αT dan reaktivitas void (αV masingmasing bernilai negatif dalam rentang 4,972×10-5 - 5,909×10-5 dan 2,596×10-2- 2,8287×10-2 ∆k/k/K. Dapat disimpulkan bahwa teras SM-MSR memberikan nilai negatif di kedua koefisien reaktivitas tersebut untuk setiap fraksi,, sehingga memenuhi kriteria keselamatan dan keselamatan melekat. Kata kunci: SM-MSR (small mobile-molten salt reactor, bahan bakar LiF-BeF2-ThF4-UF4, keselamatan melekat, koefisien reaktivitas temperatur, koefisien reaktivitas void   The analysis of neutronic performance has

Thermodynamic assessment of the LiF–ThF{sub 4}–PuF{sub 3}–UF{sub 4} system

Energy Technology Data Exchange (ETDEWEB)

Capelli, E. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, 76125 Karlsruhe (Germany); Department of Radiation Science and Technology, Faculty of Applied Physics, Delft University of Technology, Delft 2629JB (Netherlands); Beneš, O., E-mail: ondrej.benes@ec.europa.eu [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, 76125 Karlsruhe (Germany); Konings, R.J.M. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, 76125 Karlsruhe (Germany); Department of Radiation Science and Technology, Faculty of Applied Physics, Delft University of Technology, Delft 2629JB (Netherlands)

2015-07-15

The LiF–ThF{sub 4}–PuF{sub 3}–UF{sub 4} system is the reference salt mixture considered for the Molten Salt Fast Reactor (MSFR) concept started with PuF{sub 3}. In order to obtain the complete thermodynamic description of this quaternary system, two binary systems (ThF{sub 4}–PuF{sub 3} and UF{sub 4}–PuF{sub 3}) and two ternary systems (LiF–ThF{sub 4}–PuF{sub 3} and LiF–UF{sub 4}–PuF{sub 3}) have been assessed for the first time. The similarities between CeF{sub 3}/PuF{sub 3} and ThF{sub 4}/UF{sub 4} compounds have been taken into account for the presented optimization as well as in the experimental measurements performed, which have confirmed the temperatures predicted by the model. Moreover, the experimental results and the thermodynamic database developed have been used to identify potential compositions for the MSFR fuel and to evaluate the influence of partial substitution of ThF{sub 4} by UF{sub 4} in the salt.

Electrochemical behaviour of ThF4 in LiCl-KCl eutectic

International Nuclear Information System (INIS)

Agarwal, Renu; Mukerjee, S.K.; Ramakumar, K.L.

2016-01-01

Pyrochemical processing of nuclear fuels is an integral part of molten salt reactor technology. Thorium containing molten salt reactors are relevant for transmutation of minor actinides and utilizations of vast thorium resources. Understanding chemical and electrochemical behavior of actinide and lanthanide ions in chloride melts is an important task in this process. A eutectic of lithium and potassium chloride is found to be the most suitable salt for this study due to its low melting, high reduction potential and significant solubility of most of the actinide and lanthanide salts. However, electrochemistry of thorium in chloride melt is inconsistent due to dispute over the presence of Th(II) cation along with Th(IV). In the present experiments, cyclic-voltammograms of ThF 4 in LiCl-KCl eutectic salt were measured using three electrodes cell, where all the electrodes were 1 mm molybdenum wires and counter electrode wire was twisted into a spiral shape to increase surface area and was used for mixing the salts in molten state. Cyclic-voltammograms of pure eutectic melt and with ThF 4 were measured at scanning rates 50-300 mV/s, at 648 K and 723 K. Diffusion coefficient of Th 4+ was calculated using Delahay equation

Preliminary Analysis on the Management Options of IRT-DPRK Research Reactor

Energy Technology Data Exchange (ETDEWEB)

Lee, Jung-Hyun; Kim, Minsoo; Hwang, Yongsoo [Korea Institute of Nuclear Nonproliferation and Control, Daejeon (Korea, Republic of)

2015-05-15

Although IRT-DPRK was upgraded several times, operation lifetime was already exhausted and thus management policy is needed to deal with the aging of IRT-DPRK. For example, IRT- 2000 type nuclear reactors in Georgia and Bulgaria had been shut down to refurbish or decommissioned to establish new low power facilities. However, the existing negotiations and agreements related to the nuclear issues on North Korea have been focused on the 'denuclearization', and thus the issues on the IRTDPRK were not handled. In recent, a group of USA scientists has suggested that IRT-DPRK should be refurbished to establish the 'Scientific cent for excellence' like the Cooperative Threat Reduction program applied in Russia and the former Soviet Union (FSU). In this paper, we examined the several options to manage the IRT-DPRK through the study of similar foreign cases. Due to the lack of the detailed and standardized information, it is impossible to suggest the best option at this moment. In order to do that, the further research on the detailed procedures, radioactive wastes, the standards of safety and security are needed.

Thermodynamic assessment of the LiF–ThF4–PuF3–UF4 system

NARCIS (Netherlands)

Capelli, E.; Benes, O.; Konings, R.J.M.

2015-01-01

The LiF–ThF4–PuF3–UF4 system is the reference salt mixture considered for the Molten Salt Fast Reactor (MSFR) concept started with PuF3. In order to obtain the complete thermodynamic description of this quaternary system, two binary systems (ThF4–PuF3 and UF4–PuF3) and two ternary systems

Explanatory IRT Analysis Using the SPIRIT Macro in SPSS

Directory of Open Access Journals (Sweden)

DiTrapani, Jack

2018-04-01

Full Text Available Item Response Theory (IRT is a modeling framework that can be applied to a large variety of research questions spanning several disciplines. To make IRT models more accessible for the general researcher, a free tool has been created that can easily conduct one-parameter logistic IRT (1PL analyses using the convenient point-and-click interface in SPSS without any required downloads or add-ons. This tool, the SPIRIT macro, can fit 1PL models with person and item covariates, DIF analyses, multidimensional models, multigroup models, rating scale models, and several other variations. Example explanatory models are presented with an applied dataset containing responses to an ADHD rating scale. Illustrations of how to fit basic 1PL models as well as two more complicated analyses using SPIRIT are given.

2011 Puget Sound LiDAR Consortium (PSLC) Topographic LiDAR: Rattlesnake

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Watershed Sciences, Inc. (WSI) collected Light Detection and Ranging (LiDAR) data on six days between September 15th and November 5th, and from November 6th - 13th,...

A neutron radiography facility on the IRT-2000 reactor

International Nuclear Information System (INIS)

Khadduri, I.Y.

1976-01-01

A neutron radiography facility has been constructed on the thermal neutron channel of the IRT-2000 reactor. A collimated thermal neutron beam exposure area of 10 cm diameter is obtained with an L/D ratio of 48.8. The film used is cellulose nitrate coated with lithium tetraborate which is insensitive to gamma and beta radiation. Some pictures with good contrast and resolution have been obtained. Pictures of parts of an IRT-2000 reactor fuel pin have also been recorded. (orig) [de

Using the Item Response Theory (IRT) for Educational Evaluation through Games

Science.gov (United States)

Euzébio Batista, Marcelo Henrique; Victória Barbosa, Jorge Luis; da Rosa Tavares, João Elison; Hackenhaar, Jonathan Luis

2013-01-01

This article shows the application of Item Response Theory (IRT) for educational evaluation using games. The article proposes a computational model to create user profiles, called Psychometric Profile Generator (PPG). PPG uses the IRT mathematical model for exploring the levels of skills and behaviors in the form of items and/or stimuli. The model…

Event displays from Beam 2 in ATLAS, November 20th, 2009

CERN Multimedia

ATLAS collaboration

2009-01-01

ATLAS event displays and related information from the LHC restart in 2009. We recorded today, Friday November 20th, the first so-called "Beam Splash" events. For these events the beam in one arm of the LHC was dumped onto closed collimators located 140 meters upstream and downstream of ATLAS. The collision leads to a large number of detectable secondary particles longitudinally traversing the detect

Event displays from Beam Halo in ATLAS, November 20th, 2009

CERN Multimedia

ATLAS collaboration

2009-01-01

ATLAS event displays and related information from the LHC restart in 2009. We recorded today, Friday November 20th, the first so-called "Beam Splash" events. For these events the beam in one arm of the LHC was dumped onto closed collimators located 140 meters upstream and downstream of ATLAS. The collision leads to a large number of detectable secondary particles longitudinally traversing the detect

Event displays from Beam 01 in ATLAS, November 20th, 2009

CERN Multimedia

atlas collaboration

2009-01-01

ATLAS event displays and related information from the LHC restart in 2009. We recorded on, Friday November 20th, the first so-called "Beam Splash" events. For these events the beam in one arm of the LHC was dumped onto closed collimators located 140 meters upstream and downstream of ATLAS. The collision leads to a large number of detectable secondary particles longitudinally traversing the detector

IRT-based test construction

OpenAIRE

van der Linden, Willem J.; Theunissen, T.J.J.M.; Boekkooi-Timminga, Ellen; Kelderman, Henk

1987-01-01

Four discussions of test construction based on item response theory (IRT) are presented. The first discussion, "Test Design as Model Building in Mathematical Programming" (T.J.J.M. Theunissen), presents test design as a decision process under certainty. A natural way of modeling this process leads to mathematical programming. General models of test construction are discussed, with information about algorithms and heuristics; ideas about the analysis and refinement of test constraints are also...

Comparing of four IRT models when analyzing two tests for inductive reasoning

NARCIS (Netherlands)

de Koning, E.; Sijtsma, K.; Hamers, J.H.M.

2002-01-01

This article discusses the use of the nonparametric IRT Mokken models of monotone homogeneity and double monotonicity and the parametric Rasch and Verhelst models for the analysis of binary test data. First, the four IRT models are discussed and compared at the theoretical level, and for each model,

The Infrared-Optical Telescope (IRT) of the Exist Observatory

Science.gov (United States)

Kutyrev, Alexander; Bloom, Joshua; Gehrels, Neil; Golisano, Craig; Gong, Quan; Grindlay, Jonathan; Moseley, Samuel; Woodgate, Bruce

2010-01-01

The IRT is a 1.1m visible and infrared passively cooled telescope, which can locate, identify and obtain spectra of GRB afterglows at redshifts up to z 20. It will also acquire optical-IR, imaging and spectroscopy of AGN and transients discovered by the EXIST (The Energetic X-ray Imaging Survey Telescope). The IRT imaging and spectroscopic capabilities cover a broad spectral range from 0.32.2m in four bands. The identical fields of view in the four instrument bands are each split in three subfields: imaging, objective prism slitless for the field and objective prism single object slit low resolution spectroscopy, and high resolution long slit on single object. This allows the instrument, to do simultaneous broadband photometry or spectroscopy of the same object over the full spectral range, thus greatly improving the efficiency of the observatory and its detection limits. A prompt follow up (within three minutes) of the transient discovered by the EXIST makes IRT a unique tool for detection and study of these events, which is particularly valuable at wavelengths unavailable to the ground based observatories.

Teaching systems thinking to 4th and 5th graders using Environmental Dashboard display technology.

Science.gov (United States)

Clark, Shane; Petersen, John E; Frantz, Cindy M; Roose, Deborah; Ginn, Joel; Rosenberg Daneri, Daniel

2017-01-01

Tackling complex environmental challenges requires the capacity to understand how relationships and interactions between parts result in dynamic behavior of whole systems. There has been convincing research that these "systems thinking" skills can be learned. However, there is little research on methods for teaching these skills to children or assessing their impact. The Environmental Dashboard is a technology that uses "sociotechnical" feedback-information feedback designed to affect thought and behavior. Environmental Dashboard (ED) combines real-time information on community resource use with images and words that reflect pro-environmental actions of community members. Prior research indicates that ED supports the development of systems thinking in adults. To assess its impact on children, the technology was installed in a primary school and children were passively exposed to ED displays. This resulted in no measurable impact on systems thinking skills. The next stage of this research examined the impact of actively integrating ED into lessons on electricity in 4th and 5th grade. This active integration enhanced both content-related systems thinking skills and content retention.

Radiation monitoring program at nuclear scientific experimental and educational center - IRT-Sofia

International Nuclear Information System (INIS)

Mladenov, A.; Stankov, D.; Marinov, K.; Nonova, T.; Krezhov, K.

2012-01-01

Ensuring minimal risk of personnel exposure without exceeding the dose limits is the main task of the General Program for Radiation Monitoring of Nuclear Scientific Experimental and Education Centre (NSEEC) with research reactor IRT. Since 2006 the IRT-Sofia is equipped with a new and modern Radiation Monitoring System (RMS). All RMS detectors are connected to the server RAMSYS. They have online (real-time) visualization in two workstations with RAMVISION software. The RMS allows the implementation of technological and environmental monitoring at the nuclear facility site. Environmental monitoring with the RMS external system includes monitoring of dose rate; alpha and beta activity; radon activity; Po-218, Po-214, Po-212 activity; gamma control of vehicles. Technological control of reactor gases includes: Alpha beta particulate monitor; Iodine monitor; Noble gases monitor; Stack flow monitor. The General Program based on the radiation monitoring system allows real-time monitoring and control of radiation parameters in the controlled area and provides for a high level of radiation protection of IRT staff and users of its facilities. This paper presents the technical and functional parameters of the radiation monitoring system and radiation protection activities within the restricted zone in IRT facilities. (authors)

Preparation and Characterisation of LiFePO4/CNT Material for Li-Ion Batteries

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Rushanah Mohamed

2011-01-01

Full Text Available Li-ion battery cathode materials were synthesised via a mechanical activation and thermal treatment process and systematically studied. LiFePO4/CNT composite cathode materials were successfully prepared from LiFePO4 material. The synthesis technique involved growth of carbon nanotubes onto the LiFePO4 using a novel spray pyrolysis-modified CVD technique. The technique yielded LiFePO4/CNT composite cathode material displaying good electrochemical activity. The composite cathode exhibited excellent electrochemical performances with 163 mAh/g discharge capacity with 94% cycle efficiency at a 0.1 C discharge rate in the first cycle, with a capacity fade of approximately 10% after 30 cycles. The results indicate that carbon nanotube addition can enable LiFePO4 to display a higher discharge capacity at a fast rate with high efficiency. The research is of potential interest for the application of carbon nanotubes as a new conducting additive in cathode preparation and for the development of high-power Li-ion batteries for hybrid electric vehicles.

Measuring individual significant change on the Beck Depression Inventory-II through IRT-based statistics.

NARCIS (Netherlands)

Brouwer, D.; Meijer, R.R.; Zevalkink, D.J.

2013-01-01

Several researchers have emphasized that item response theory (IRT)-based methods should be preferred over classical approaches in measuring change for individual patients. In the present study we discuss and evaluate the use of IRT-based statistics to measure statistical significant individual

Thermodynamic assessment of the LiF–NaF–BeF{sub 2}–ThF{sub 4}–UF{sub 4} system

Energy Technology Data Exchange (ETDEWEB)

Capelli, E.; Beneš, O., E-mail: ondrej.benes@ec.europa.eu; Konings, R.J.M.

2014-06-01

The present study describes the full thermodynamic assessment of the LiF–NaF–BeF{sub 2}–ThF{sub 4}–UF{sub 4} system which is one of the key systems considered for a molten salt reactor fuel. The work is an extension of the previously assessed LiF–NaF–ThF{sub 4}–UF{sub 4} system with addition of BeF{sub 2} which is characterized by very low neutron capture cross section and a relatively low melting point. To extend the database the binary BeF{sub 2}–ThF{sub 4} and BeF{sub 2}–UF{sub 4} systems were optimized and the novel data were used for the thermodynamic assessment of BeF{sub 2} containing ternary systems for which experimental data exist in the literature. The obtained database is used to optimize the molten salt reactor fuel composition and to assess its properties with the emphasis on the melting behaviour.

High dose rate (HDR) and low dose rate (LDR) interstitial irradiation (IRT) of the rat spinal cord

International Nuclear Information System (INIS)

Pop, Lucas A.M.; Plas, Mirjam van der; Skwarchuk, Mark W.; Hanssen, Alex E.J.; Kogel, Albert J. van der

1997-01-01

Purpose: To describe a newly developed technique to study radiation tolerance of rat spinal cord to continuous interstitial irradiation (IRT) at different dose rates. Material and methods: Two parallel catheters are inserted just laterally on each side of the vertebral bodies from the level of Th 10 to L 4 . These catheters are afterloaded with two 192 Ir wires of 4 cm length each (activity 1-2.3 mCi/cm) for the low dose rate (LDR) IRT or connected to the HDR micro-Selectron for the high dose rate (HDR) IRT. Spinal cord target volume is located at the level of Th 12 -L 2 . Due to the rapid dose fall-off around the implanted sources, a dose inhomogeneity across the spinal cord thickness is obtained in the dorso-ventral direction. Using the 100% reference dose (rate) at the ventral side of the spinal cord to prescribe the dose, experiments have been carried out to obtain complete dose response curves at average dose rates of 0.49, 0.96 and 120 Gy/h. Paralysis of the hind-legs after 5-6 months and histopathological examination of the spinal cord of each irradiated rat are used as experimental endpoints. Results: The histopathological damage seen after irradiation is clearly reflected the inhomogeneous dose distribution around the implanted catheters, with the damage predominantly located in the dorsal tract of the cord or dorsal roots. With each reduction in average dose rate, spinal cord radiation tolerance is significantly increased. When the dose is prescribed at the 100% reference dose rate, the ED 50 (induction of paresis in 50% of the animals) for the HDR-IRT is 17.3 Gy. If the average dose rate is reduced from 120 Gy/h to 0.96 or 0.49 Gy/h, a 2.9- or 4.7-fold increase in the ED 50 values to 50.3 Gy and 80.9 Gy is observed; for the dose prescribed at the 150% reference dose rate (dorsal side of cord) ED 50 values are 26.0, 75.5 and 121.4 Gy, respectively. Using different types of analysis and in dependence of the dose prescription and reference dose rate, the �

Application of multidimensional IRT models to longitudinal data

NARCIS (Netherlands)

te Marvelde, J.M.; Glas, Cornelis A.W.; Van Landeghem, Georges; Van Damme, Jan

2006-01-01

The application of multidimensional item response theory (IRT) models to longitudinal educational surveys where students are repeatedly measured is discussed and exemplified. A marginal maximum likelihood (MML) method to estimate the parameters of a multidimensional generalized partial credit model

Clinical Effect of IRT-5 Probiotics on Immune Modulation of Autoimmunity or Alloimmunity in the Eye

Directory of Open Access Journals (Sweden)

Jaeyoung Kim

2017-10-01

Full Text Available Background: Although the relation of the gut microbiota to a development of autoimmune and inflammatory diseases has been investigated in various animal models, there are limited studies that evaluate the effect of probiotics in the autoimmune eye disease. Therefore, we aimed to investigate the effect of IRT-5 probiotics consisting of Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus reuteri, Bifidobacterium bifidum, and Streptococcus thermophilus on the autoimmunity of uveitis and dry eye and alloimmunity of corneal transplantation. Methods: Experimental autoimmune uveitis was induced by subcutaneous immunization with interphotoreceptor-binding protein and intraperitoneal injection of pertussis toxin in C57BL/6 (B6 mice. For an autoimmune dry eye model, 12-weeks-old NOD.B10.H2b mice were used. Donor cornea of B6 mice was transplanted into BALB/C mice. IRT-5 probiotics or phosphate buffered saline (PBS were administered for three weeks immediately after induction of uveitis or transplantation. The inflammation score of the retinal tissues, dry eye manifestations (corneal staining and tear secretion, and graft survival were measured in each model. The changes of T cells were evaluated in drainage lymph nodes using fluorescence-activated cell sorting. Results: Retinal histology score in IRT-5 group of uveitis was lower than that in PBS group (p = 0.045. Ocular staining score was lower (p < 0.0001 and tear secretion was higher (p < 0.0001 in the IRT-5 group of NOD.B10.H2b mice than that in the PBS group. However, the graft survival in the IRT-5 group was not different from those of PBS group. The percentage of regulatory T cells was increased in the IRT-5-treated dry eye models (p = 0.032. The percentage of CD8+IL-17hi (p = 0.027 and CD8+ interferon gamma (IFNγhi cells (p = 0.022 were significantly decreased in the IRT-5-treated uveitis models and the percentage of CD8+IFNγhi cells was markedly reduced (p = 0.036 in IRT-5-treated dry

Loglinear multidimensional IRT models for polytomously scired Items

NARCIS (Netherlands)

Kelderman, Henk

1988-01-01

A loglinear item response theory (IRT) model is proposed that relates polytomously scored item responses to a multidimensional latent space. Each item may have a different response function where each item response may be explained by one or more latent traits. Item response functions may follow a

Loglinear multidimensional IRT models for polytomously scored items

NARCIS (Netherlands)

Kelderman, Henk; Rijkes, Carl P.M.; Rijkes, Carl

1994-01-01

A loglinear IRT model is proposed that relates polytomously scored item responses to a multidimensional latent space. The analyst may specify a response function for each response, indicating which latent abilities are necessary to arrive at that response. Each item may have a different number of

General plan for the partial dismantling of the IRT-Sofia research reactor

Directory of Open Access Journals (Sweden)

Apostolov Tihomir G.

2006-01-01

Full Text Available After the decision of the Bulgarian Government to reconstruct it, the strategy concerning the IRT-Sofia Research Reactor is to partially dismantle the old systems and equipment. The removal of the reactor core and replacement of old equipment will not pose any significant problems. For a more efficient use of existing resources, there is a need for an engineering project which has been already prepared under the title "General Plan for the Partial Dismantling of Equipment at the IRT-Sofia as a Part of the Reconstruction into a Low Power RR".

Detection of Differential Item Functioning with Nonlinear Regression: A Non-IRT Approach Accounting for Guessing

Science.gov (United States)

Drabinová, Adéla; Martinková, Patrícia

2017-01-01

In this article we present a general approach not relying on item response theory models (non-IRT) to detect differential item functioning (DIF) in dichotomous items with presence of guessing. The proposed nonlinear regression (NLR) procedure for DIF detection is an extension of method based on logistic regression. As a non-IRT approach, NLR can…

Gibberellic acid alleviates cadmium toxicity by reducing nitric oxide accumulation and expression of IRT1 in Arabidopsis thaliana

International Nuclear Information System (INIS)

Zhu, Xiao Fang; Jiang, Tao; Wang, Zhi Wei; Lei, Gui Jie; Shi, Yuan Zhi; Li, Gui Xin; Zheng, Shao Jian

2012-01-01

Highlights: ► Cd reduces endogenous GA levels in Arabidopsis. ► GA exogenous applied decreases Cd accumulation in plant. ► GA suppresses the Cd-induced accumulation of NO. ► Decreased NO level downregulates the expression of IRT1. ► Suppressed IRT1 expression reduces Cd transport across plasma membrane. - Abstract: Gibberellic acid (GA) is involved in not only plant growth and development but also plant responses to abiotic stresses. Here it was found that treating the plants with GA concentrations from 0.1 to 5 μM for 24 h had no obvious effect on root elongation in the absence of cadmium (Cd), whereas in the presence of Cd 2+ , GA at 5 μM improved root growth, reduced Cd content and lipid peroxidation in the roots, indicating that GA can partially alleviate Cd toxicity. Cd 2+ increased nitric oxide (NO) accumulation in the roots, but GA remarkably reduced it, and suppressed the up-regulation of the expression of IRT1. In contrary, the beneficial effect of GA on alleviating Cd toxicity was not observed in an IRT1 knock-out mutant irt1, suggesting the involvement of IRT1 in Cd 2+ absorption. Furthermore, the GA-induced reduction of NO and Cd content can also be partially reversed by the application of a NO donor (S-nitrosoglutathione [GSNO]). Taken all these together, the results showed that GA-alleviated Cd toxicity is mediated through the reduction of the Cd-dependent NO accumulation and expression of Cd 2+ uptake related gene-IRT1 in Arabidopsis.

2012 Puget Sound LiDAR Consortium (PSLC) Topographic LiDAR: Chehalis River Watershed Area, Washington

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Watershed Sciences, Inc. (WSI) collected Light Detection and Ranging (LiDAR) data for the Chehalis River Watershed study area on January 28th, February 2nd-7th,...

Overexpression of ZmIRT1 and ZmZIP3 Enhances Iron and Zinc Accumulation in Transgenic Arabidopsis.

Directory of Open Access Journals (Sweden)

Suzhen Li

Full Text Available Iron and zinc are important micronutrients for both the growth and nutrient availability of crop plants, and their absorption is tightly controlled by a metal uptake system. Zinc-regulated transporters, iron-regulated transporter-like proteins (ZIP, is considered an essential metal transporter for the acquisition of Fe and Zn in graminaceous plants. Several ZIPs have been identified in maize, although their physiological function remains unclear. In this report, ZmIRT1 was shown to be specifically expressed in silk and embryo, whereas ZmZIP3 was a leaf-specific gene. Both ZmIRT1 and ZmZIP3 were shown to be localized to the plasma membrane and endoplasmic reticulum. In addition, transgenic Arabidopsis plants overexpressing ZmIRT1 or ZmZIP3 were generated, and the metal contents in various tissues of transgenic and wild-type plants were examined based on ICP-OES and Zinpyr-1 staining. The Fe and Zn concentration increased in roots and seeds of ZmIRT1-overexpressing plants, while the Fe content in shoots decreased. Overexpressing ZmZIP3 enhanced Zn accumulation in the roots of transgenic plants, while that in shoots was repressed. In addition, the transgenic plants showed altered tolerance to various Fe and Zn conditions compared with wild-type plants. Furthermore, the genes associated with metal uptake were stimulated in ZmIRT1 transgenic plants, while those involved in intra- and inter- cellular translocation were suppressed. In conclusion, ZmIRT1 and ZmZIP3 are functional metal transporters with different ion selectivities. Ectopic overexpression of ZmIRT1 may stimulate endogenous Fe uptake mechanisms, which may facilitate metal uptake and homeostasis. Our results increase our understanding of the functions of ZIP family transporters in maize.

Measurement Invariance in Careers Research: Using IRT to Study Gender Differences in Medical Students' Specialization Decisions

Science.gov (United States)

Behrend, Tara S.; Thompson, Lori Foster; Meade, Adam W.; Newton, Dale A.; Grayson, Martha S.

2008-01-01

The current study demonstrates the use of item response theory (IRT) to conduct measurement invariance analyses in careers research. A self-report survey was used to assess the importance 1,363 fourth-year medical students placed on opportunities to provide comprehensive patient care when choosing a career specialty. IRT analyses supported…

Gibberellic acid alleviates cadmium toxicity by reducing nitric oxide accumulation and expression of IRT1 in Arabidopsis thaliana

Energy Technology Data Exchange (ETDEWEB)

Zhu, Xiao Fang [State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058 (China); Jiang, Tao [Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, College of Life Sciences, Zhejiang University, Hangzhou 310058 (China); Wang, Zhi Wei [State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058 (China); Lei, Gui Jie [Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, College of Life Sciences, Zhejiang University, Hangzhou 310058 (China); Shi, Yuan Zhi [The Key Laboratory of Tea Chemical Engineering, Ministry of Agriculture, Yunqi Road 1, Hangzhou 310008 (China); Li, Gui Xin, E-mail: guixinli@zju.edu.cn [College of Agronomy and Biotechnology, Zhejiang University, Hangzhou 310058 (China); Zheng, Shao Jian [State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058 (China); Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education, College of Life Sciences, Zhejiang University, Hangzhou 310058 (China)

2012-11-15

Highlights: Black-Right-Pointing-Pointer Cd reduces endogenous GA levels in Arabidopsis. Black-Right-Pointing-Pointer GA exogenous applied decreases Cd accumulation in plant. Black-Right-Pointing-Pointer GA suppresses the Cd-induced accumulation of NO. Black-Right-Pointing-Pointer Decreased NO level downregulates the expression of IRT1. Black-Right-Pointing-Pointer Suppressed IRT1 expression reduces Cd transport across plasma membrane. - Abstract: Gibberellic acid (GA) is involved in not only plant growth and development but also plant responses to abiotic stresses. Here it was found that treating the plants with GA concentrations from 0.1 to 5 {mu}M for 24 h had no obvious effect on root elongation in the absence of cadmium (Cd), whereas in the presence of Cd{sup 2+}, GA at 5 {mu}M improved root growth, reduced Cd content and lipid peroxidation in the roots, indicating that GA can partially alleviate Cd toxicity. Cd{sup 2+} increased nitric oxide (NO) accumulation in the roots, but GA remarkably reduced it, and suppressed the up-regulation of the expression of IRT1. In contrary, the beneficial effect of GA on alleviating Cd toxicity was not observed in an IRT1 knock-out mutant irt1, suggesting the involvement of IRT1 in Cd{sup 2+} absorption. Furthermore, the GA-induced reduction of NO and Cd content can also be partially reversed by the application of a NO donor (S-nitrosoglutathione [GSNO]). Taken all these together, the results showed that GA-alleviated Cd toxicity is mediated through the reduction of the Cd-dependent NO accumulation and expression of Cd{sup 2+} uptake related gene-IRT1 in Arabidopsis.

Nuclear Research Center IRT reactor dynamics calculation

International Nuclear Information System (INIS)

Aleman Fernandez, J.R.

1990-01-01

The main features of the code DIRT, for dynamical calculations are described in the paper. With the results obtained by the program, an analysis of the dynamic behaviour of the Research Reactor IRT of the Nuclear Research Center (CIN) is performed. Different transitories were considered such as variation of the system reactivity, coolant inlet temperature variation and also variations of the coolant velocity through the reactor core. 3 refs

Thermodynamic assessment of the LiF-NaF-ThF4-UF4 system

International Nuclear Information System (INIS)

Benes, O.; Beilmann, M.; Konings, R.J.M.

2010-01-01

A thermodynamic assessment of the LiF-NaF-ThF 4 -UF 4 system is presented in this study. The binary phase diagrams are optimized based on the known experimental data and the excess Gibbs energies of liquid and solid solutions are described using a modified quasi chemical model and polynomial formalism respectively. The higher order systems are extrapolated according to asymmetric Toop mathematical formalism. Based on the developed thermodynamic database the fuel composition of the molten salt fast reactor is optimized. In total three different fuel compositions are identified. Properties of these fuel compositions such as melting point, vapour pressure and the boiling temperature are derived from the obtained thermodynamic assessment and are presented in this study.

Electrochemical behavior of Li/LiV3O8 secondary cells

Science.gov (United States)

Bak, Hyo Rim; Lee, Jae Ha; Kim, Bok Ki; Yoon, Woo Young

2013-03-01

Li/LiV3O8 secondary cells with Li-foil and Li-powder anodes were fabricated, and their electrical properties were compared. Using the powder anode, a cell with an initial discharge capacity of 260 mAh g-1 that could be operated for over 100 cycles was obtained. The porous Li-powder electrode was safely synthesized by pressing an emulsion droplet onto an SUS mesh. A threefold increase in the electrical conductivity of the LiV3O8 cathode was achieved by the addition of carbon using a vibration pot mill. Using the powder anode resulted in 80% capacity retention at the 100th cycle, while that using the foil electrode was 46%; the 1.0 Crate/ 0.1 C-rate capacity ratio also increased from 44% to 60%. A cell employing the LiV3O8-carbon composite cathode showed better electrical performance, a capacity retention of 90% after 50 cycles, and an increase in rate capacity ratio. The crystal structure and morphology of the LiV3O8-C composite were investigated by x-ray diffraction and scanning electron microscopy.

IRT-Estimated Reliability for Tests Containing Mixed Item Formats

Science.gov (United States)

Shu, Lianghua; Schwarz, Richard D.

2014-01-01

As a global measure of precision, item response theory (IRT) estimated reliability is derived for four coefficients (Cronbach's a, Feldt-Raju, stratified a, and marginal reliability). Models with different underlying assumptions concerning test-part similarity are discussed. A detailed computational example is presented for the targeted…

Licensing activities for the partial decommissioning of IRT-2000 research reactor in Sofia

International Nuclear Information System (INIS)

Apostolov, T.; Ilieva, Kr.; Papukchiev, A.; Kalchev, B.

2001-01-01

The project for refurbishment of IRT-2000 research reactor in Sofia into low-power reactor (200 kW) is based on the retention of some IRT-2000 buildings, facilities and equipment. The activities, which determine the partial decommissioning should be realized in accordance with preliminary developed licensing documents as General Plan, Safety Analysis Report and Environment Impact assessment Report. The goal of these documents is to provide and guarantee safe and effective activities with radioactive materials, to define strictly the dismantling procedures, and in the same time to minimize their influence on the environment. The Technical Tasks for General Plan, Safety Analysis Report and Environment Impact Assessment Report have been prepared and will be presented as preliminary licensing documents to the National Regulatory Body for approval before their application. A Quality Management system is being developed nowadays at INRNE. After its certification some requirements of the regulatory body will be completed. This certified QA system is a major part of the licensing procedure for the reconstruction of IRT-2000 research reactor. (author)

The development of the nuclear physics in Latvia II. The building of the Research Nuclear Reactor IRT

International Nuclear Information System (INIS)

Ulmanis, U.

2004-01-01

Nuclear research reactor IRT of the Academy of Sciences was built near Riga in Salaspils. IRT is pool aqueous - aqueous reactor with nuclear fuel U-235 contained elements, located in the core at a depth of ∼ 7 m under distilled water. Ten horizontal and 10-15 vertical experimental channels are employed in experimental research with the use of neutron fluxes. For the research with gamma rays is constructed radiation loop facility with liquid In-Ga-SN solid solution as intensive gamma-ray sources. Main activities of IRT are to conduct research in nuclear spectroscopy, neutron activation analysis, neutron diffraction and radiation physics, chemistry and biology. (authors)

A new network of faint calibration stars from the near infrared spectrometer (NIRS) on the IRTS

Science.gov (United States)

Freund, Minoru M.; Matsuura, Mikako; Murakami, Hiroshi; Cohen, Martin; Noda, Manabu; Matsuura, Shuji; Matsumoto, Toshio

1997-01-01

The point source extraction and calibration of the near infrared spectrometer (NIRS) onboard the Infrared Telescope in Space (IRTS) is described. About 7 percent of the sky was observed during a one month mission in the range of 1.4 micrometers to 4 micrometers. The accuracy of the spectral shape and absolute values of calibration stars provided by the NIRS/IRTS were validated.

Bayesian Estimation of the Logistic Positive Exponent IRT Model

Science.gov (United States)

Bolfarine, Heleno; Bazan, Jorge Luis

2010-01-01

A Bayesian inference approach using Markov Chain Monte Carlo (MCMC) is developed for the logistic positive exponent (LPE) model proposed by Samejima and for a new skewed Logistic Item Response Theory (IRT) model, named Reflection LPE model. Both models lead to asymmetric item characteristic curves (ICC) and can be appropriate because a symmetric…

Electrochemical behaviors of wax-coated Li powder/Li 4Ti 5O 12 cells

Science.gov (United States)

Park, Han Eol; Seong, Il Won; Yoon, Woo Young

The wax-coated Li powder specimen was effectively synthesized using the drop emulsion technique (DET). The wax layer on the powder was verified by SEM, Focused Ion Beam (FIB), EDX and XPS. The porosity of a sintered wax-coated Li electrode was measured by linear sweep voltammetry (LSV) and compared with that of a bare, i.e., un-coated Li electrode. The electrochemical behavior of the wax-coated Li powder anode cell was examined by the impedance analysis and cyclic testing methods. The cyclic behavior of the wax-coated Li powder anode with the Li 4Ti 5O 12 (LTO) cathode cell was examined at a constant current density of 0.35 mA cm -2 with the cut-off voltages of 1.2-2.0 V at 25 °C. Over 90% of the initial capacity of the cell remained even after the 300th cycle. The wax-coated Li powder was confirmed to be a stable anode material.

IRT analyses of the Swedish Dark Triad Dirty Dozen

Directory of Open Access Journals (Sweden)

Danilo Garcia

2018-03-01

Full Text Available Background: The Dark Triad (i.e., Machiavellianism, narcissism, and psychopathy can be captured quickly with 12 items using the Dark Triad Dirty Dozen (Jonason and Webster, 2010. Previous Item Response Theory (IRT analyses of the original English Dark Triad Dirty Dozen have shown that all three subscales adequately tap into the dark domains of personality. The aim of the present study was to analyze the Swedish version of the Dark Triad Dirty Dozen using IRT. Method: 570 individuals (nmales = 326, nfemales = 242, and 2 unreported, including university students and white-collar workers with an age range between 19 and 65 years, responded to the Swedish version of the Dark Triad Dirty Dozen (Garcia et al., 2017a,b. Results: Contrary to previous research, we found that the narcissism scale provided most information, followed by psychopathy, and finally Machiavellianism. Moreover, the psychopathy scale required a higher level of the latent trait for endorsement of its items than the narcissism and Machiavellianism scales. Overall, all items provided reasonable amounts of information and are thus effective for discriminating between individuals. The mean item discriminations (alphas were 1.92 for Machiavellianism, 2.31 for narcissism, and 1.99 for psychopathy. Conclusion: This is the first study to provide IRT analyses of the Swedish version of the Dark Triad Dirty Dozen. Our findings add to a growing literature on the Dark Triad Dirty Dozen scale in different cultures and highlight psychometric characteristics, which can be used for comparative studies. Items tapping into psychopathy showed higher thresholds for endorsement than the other two scales. Importantly, the narcissism scale seems to provide more information about a lack of narcissism, perhaps mirroring cultural conditions. Keywords: Psychology, Psychiatry, Clinical psychology

Solution of operational problems utilization of an EX-IRT-2000 heat exchanger

International Nuclear Information System (INIS)

Razak, Abdu

1986-01-01

The Bandung TRIGA Mark II Reactor has been successfully operated for 21 years, especially in low power operation or as neutron sources for various experiments. Most of the operating time, approximately 80% of routine operation, was dedicated for radio-isotope production. During routine operation for radio-isotope production, the reactor could not be operated at full power. The reactor was operated at 60% of the maximum power (1 MWth) due to the inability of the original heat exchanger to operate properly. The reason is that slack deposition was built-up on the secondary side of the heat exchanger. Therefore, it reduced the coefficient of heat transfer considerably. To solve the problems, a set of heat exchanger including the pump was installed In parallel with the original unit. The heat exchanger was an IRT-2000 Reactor Heat exchanger which was collected from the abandoned IRT-2000 Project. The heat exchanger has capacity of 1.25 MW. The new heat exchanger could reduced the outlet temperature of the primary coolant Into 42 deg. C. While the original-heat exchanger at the worst condition and at 600 kW of power reach outlet temperature 49 deg. C. The IRT Heat Exchanger is a counter flow heat exchanger. (author)

Solution of operational problems utilization of an EX-IRT-2000 heat exchanger

Energy Technology Data Exchange (ETDEWEB)

Razak, Abdu [Research Centre for Nuclear Techniques, National Atomic Energy Agency (Indonesia)

1986-07-01

The Bandung TRIGA Mark II Reactor has been successfully operated for 21 years, especially in low power operation or as neutron sources for various experiments. Most of the operating time, approximately 80% of routine operation, was dedicated for radio-isotope production. During routine operation for radio-isotope production, the reactor could not be operated at full power. The reactor was operated at 60% of the maximum power (1 MWth) due to the inability of the original heat exchanger to operate properly. The reason is that slack deposition was built-up on the secondary side of the heat exchanger. Therefore, it reduced the coefficient of heat transfer considerably. To solve the problems, a set of heat exchanger including the pump was installed In parallel with the original unit. The heat exchanger was an IRT-2000 Reactor Heat exchanger which was collected from the abandoned IRT-2000 Project. The heat exchanger has capacity of 1.25 MW. The new heat exchanger could reduced the outlet temperature of the primary coolant Into 42 deg. C. While the original-heat exchanger at the worst condition and at 600 kW of power reach outlet temperature 49 deg. C. The IRT Heat Exchanger is a counter flow heat exchanger. (author)

LiCl-LiI molten salt electrolyte with bismuth-lead positive electrode for liquid metal battery

Science.gov (United States)

Kim, Junsoo; Shin, Donghyeok; Jung, Youngjae; Hwang, Soo Min; Song, Taeseup; Kim, Youngsik; Paik, Ungyu

2018-02-01

Liquid metal batteries (LMBs) are attractive energy storage device for large-scale energy storage system (ESS) due to the simple cell configuration and their high rate capability. The high operation temperature caused by high melting temperature of both the molten salt electrolyte and metal electrodes can induce the critical issues related to the maintenance cost and degradation of electrochemical properties resulting from the thermal corrosion of materials. Here, we report a new chemistry of LiCl-LiI electrolyte and Bi-Pb positive electrode to lower the operation temperature of Li-based LMBs and achieve the long-term stability. The cell (Li|LiCl-LiI|Bi-Pb) is operated at 410 °C by employing the LiCl-LiI (LiCl:LiI = 36:64 mol %) electrolyte and Bi-Pb alloy (Bi:Pb = 55.5:44.5 mol %) positive electrode. The cell shows excellent capacity retention (86.5%) and high Coulombic efficiencies over 99.3% at a high current density of 52 mA cm-2 during 1000th cycles.

Results and Conclusions from the NASA Isokinetic Total Water Content Probe 2009 IRT Test

Science.gov (United States)

Reehorst, Andrew; Brinker, David

2010-01-01

The NASA Glenn Research Center has developed and tested a Total Water Content Isokinetic Sampling Probe. Since, by its nature, it is not sensitive to cloud water particle phase nor size, it is particularly attractive to support super-cooled large droplet and high ice water content aircraft icing studies. The instrument comprises the Sampling Probe, Sample Flow Control, and Water Vapor Measurement subsystems. Results and conclusions are presented from probe tests in the NASA Glenn Icing Research Tunnel (IRT) during January and February 2009. The use of reference probe heat and the control of air pressure in the water vapor measurement subsystem are discussed. Several run-time error sources were found to produce identifiable signatures that are presented and discussed. Some of the differences between measured Isokinetic Total Water Content Probe and IRT calibration seems to be caused by tunnel humidification and moisture/ice crystal blow around. Droplet size, airspeed, and liquid water content effects also appear to be present in the IRT calibration. Based upon test results, the authors provide recommendations for future Isokinetic Total Water Content Probe development.

The design, construction, and operation of the Integrated Radwaste Treatment System (IRTS) Drum Cell

International Nuclear Information System (INIS)

Landau, B.; Russillo, A.; Frank, D.; Garland, D.

1989-12-01

This report describes the design, construction, and the operation of the Integrated Radwaste Treatment Systems (IRTS) Drum Cell at the West Valley Demonstration Project (WVDP), West Valley, New York. The IRTS Drum Cell was designed to provide a shielded, secure storage area for the remote handling and placement of low-level Class C radioactive waste produced in the IRTS. The Drum Cell was designed to contain up to approximately 8,804 drums from decontaminated supernatant processing. This waste is to be poured into 0.27m 3 in a temperature controlled environment to ensure the cement will not be subjected to freezing and thawing cycles. A Temporary Weather Structure (TWS), a pre-engineered building, now encloses the Drum Cell and associated equipment so that remote waste-handling and placement operations can continue without regard to weather conditions. The Drum Cell was designed so that this TWS could be removed and the low-level waste entombed in place. Final disposition of this low-level waste is currently being evaluated in an Environmental Impact Statement (EIS). 10 refs., 11 figs., 1 tab

Inoculation with Bacillus subtilis and Azospirillum brasilense produces abscisic acid that reduces IRT1-mediated cadmium uptake of roots.

Science.gov (United States)

Xu, Qianru; Pan, Wei; Zhang, Ranran; Lu, Qi; Xue, Wanlei; Wu, Cainan; Song, Bixiu; Du, Shaoting

2018-05-08

Cadmium (Cd) contamination of agricultural soils represents a serious risk to crop safety. A new strategy using abscisic acid (ABA)-generating bacteria, Bacillus subtilis or Azospirillum brasilense, was developed to reduce the Cd accumulation in plants grown in Cd-contaminated soil. Inoculation with either bacterium resulted in a pronounced increase in the ABA level in wild-type Arabidopsis Col-0 plants, accompanied by a decrease in Cd levels in plant tissues, which mitigated the Cd toxicity. As a consequence, the growth of plants exposed to Cd was improved. Nevertheless, B. subtilis and A. brasilense inoculation had little effect on Cd levels and toxicity in the ABA-insensitive mutant snrk 2.2/2.3, indicating that the action of ABA is required for these bacteria to reduce Cd accumulation in plants. Furthermore, inoculation with either B. subtilis or A. brasilense down-regulated the expression of IRT1 (IRON-REGULATED TRANSPORTER 1) in the roots of wild-type plants and had little effect on Cd levels in the IRT1-knockout mutants irt1-1 and irt1-2. In summary, we conclude that B. subtilis and A. brasilense can reduce Cd levels in plants via an IRT1-dependent ABA-mediated mechanism.

Time evolution of the energy confinement time, internal inductance and effective edge safety factor on IR-T1 tokamak

International Nuclear Information System (INIS)

Salar Elahi, A; Ghoranneviss, M

2010-01-01

An attempt is made to investigate the time evolution of the energy confinement time, internal inductance and effective edge safety factor on IR-T1 tokamak. For this purpose, four magnetic pickup coils were designed, constructed and installed on the outer surface of the IR-T1 and then the Shafranov parameter (asymmetry factor) was obtained from them. On the other hand, also a diamagnetic loop was designed and installed on IR-T1 and poloidal beta was determined from it. Therefore, the internal inductance and effective edge safety factor were measured. Also, the time evolution of the energy confinement time was measured using the diamagnetic loop. Experimental results on IR-T1 show that the maximum energy confinement time (which corresponds to minimum collisions, minimum microinstabilities and minimum transport) is at low values of the effective edge safety factor (2.5 eff (a) i <0.72). The results obtained are in agreement with those obtained with the theoretical approach [1-5].

A Comparison of Item Fit Statistics for Mixed IRT Models

Science.gov (United States)

Chon, Kyong Hee; Lee, Won-Chan; Dunbar, Stephen B.

2010-01-01

In this study we examined procedures for assessing model-data fit of item response theory (IRT) models for mixed format data. The model fit indices used in this study include PARSCALE's G[superscript 2], Orlando and Thissen's S-X[superscript 2] and S-G[superscript 2], and Stone's chi[superscript 2*] and G[superscript 2*]. To investigate the…

Effect of Item Response Theory (IRT) Model Selection on Testlet-Based Test Equating. Research Report. ETS RR-14-19

Science.gov (United States)

Cao, Yi; Lu, Ru; Tao, Wei

2014-01-01

The local item independence assumption underlying traditional item response theory (IRT) models is often not met for tests composed of testlets. There are 3 major approaches to addressing this issue: (a) ignore the violation and use a dichotomous IRT model (e.g., the 2-parameter logistic [2PL] model), (b) combine the interdependent items to form a…

2012 Puget Sound LiDAR Consortium (PSLC) Topographic LiDAR: Upper Naches River, Washington

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Watershed Sciences, Inc. (WSI) collected Light Detection and Ranging (LiDAR) data of the Upper Naches River Valley and Nile Slide area of interest on September 30th,...

RIBD-IRT, Isotope Buildup and Isotope Decay from Fission Source

International Nuclear Information System (INIS)

1990-01-01

1 - Description of problem or function: RIBD-IRT calculates isotopic concentrations resulting from two fission sources with normal down- chain decay by beta emission and isomeric transfers and inter-chain coupling resulting from (n,gamma) reactions. Calculations can be made to follow an irradiation history through an unlimited number of step changes of unrestricted duration and variability including shutdown periods, restarts at different power levels and/or any other level changes. In addition, the program permits to track and modify the concentration of individual elements as they decay with time following reactor shutdown. Tracking individual elements enables one to estimate time-dependent source terms for a hypothetical LOCA based on known or postulated fission product release mechanisms. 2 - Method of solution: RIBD-IRT is a grid processor. It organizes the various members described by the fission product library data into a grid with the various linkages established from chain branching data, yield data, and neutron capture cross sections with their branching ratios. Radioactive decay includes not only the simple member-to-member cascade but also the more complex forms where branching may be partially or completely skip one or two intervening members

A Li-Garnet composite ceramic electrolyte and its solid-state Li-S battery

Science.gov (United States)

Huang, Xiao; Liu, Cai; Lu, Yang; Xiu, Tongping; Jin, Jun; Badding, Michael E.; Wen, Zhaoyin

2018-04-01

A high strength Li-Garnet solid electrolyte composite ceramic is successfully prepared via conventional solid state method with Li6.4La3Zr1.4Ta0.6O12 and nano MgO powders. Well sintered ceramic pellets and bars are obtained with 0-9 wt.% MgO. Fracture strength is approximately 135 MPa for composite ceramics with 5-9 wt.% MgO, which is ∼50% higher than that of pure Li6.4La3Zr1.4Ta0.6O12 (90 MPa). Lithium-ion conductivity of the composite is above 5 × 10-4 S cm-1 at room temperature; comparable to the pure Li6.4La3Zr1.4Ta0.6O12 material. SEM cross-sections of the composite ceramic shows a much more uniform microstructure comparing with pure ones, owing to the grain growth inhibition effect of the MgO second phase. A battery cell consisting of Li/composite ceramics/Sulfur-Carbon at 25 °C exhibits a capacity of 685 mAh g-1 at 0.2 C at the 200th cycle, while maintaining a coulombic efficiency of 100%. These results indicate that the composite ceramic Li6.4La3Zr1.4Ta0.6O12-MgO is promising for the production of electrolyte membrane and fabrication of Li-Sulfur batteries.

Comparison of the reactivity of 2-Li-C{sub 6}H{sub 4}CH{sub 2}NMe{sub 2} with MCl{sub 4} (M=Th, U). Isolation of a thorium aryl complex or a uranium benzyne complex

Energy Technology Data Exchange (ETDEWEB)

Seaman, Lani A.; Pedrick, Elizabeth A.; Wu, Guang; Hayton, Trevor W. [California Univ., Santa Barbara, CA (United States). Dept. of Chemistry and Biochemistry; Tsuchiya, Takashi; Jakubikova, Elena [North Carolina State Univ., Raleigh, NC (United States). Dept. of Chemistry

2013-09-27

Individualism under actinoids: The reaction of 2-Li-C{sub 6}H{sub 4}CH{sub 2}NMe{sub 2} with [MCl{sub 4} (dme) {sub n}] (M=Th, n=2; M=U, n=0) gives the thorium aryl complex [Th(2-C{sub 6}H{sub 4}CH{sub 2}NMe{sub 2}){sub 4}] or the uranium benzene complex Li[U(2,3-C{sub 6}H{sub 3}CH{sub 2}NMe{sub 2})(2-C{sub 6}H{sub 4}CH{sub 2}NMe{sub 2}){sub 3}]. A DFT analysis suggests that the formation of a benzyne complex with uranium but not with thorium is a kinetic and not thermodynamic effect. [German] Individualismus unter Actinoiden: Die Reaktion von 2-Li-C{sub 6}H{sub 4}CH{sub 2}NMe{sub 2} mit [MCl{sub 4} (dme) {sub n}] (M=Th, n=2; M=U, n=0) ergibt den Thoriumarylkomplex [Th(2-C{sub 6}H{sub 4}CH{sub 2}NMe{sub 2}){sub 4}] bzw. den Uranbenz-inkomplex Li[U(2,3-C{sub 6}H{sub 3}CH{sub 2}NMe{sub 2})(2-C{sub 6}H{sub 4}CH{sub 2}NMe{sub 2}){sub 3}]. Einer dichtefunktionaltheoretischen Analyse zufolge ist es kinetisch und nicht thermodynamisch bedingt, dass der Benz-inkomplex im Fall von Uran entsteht, nicht aber im Fall von Thorium.

Disentangling effects of breakup coupling and incomplete fusion in 6Li + 232Th reaction

International Nuclear Information System (INIS)

Jha, V.; Parkar, V.V.; Mohanty, A.K.; Kailas, S.

2014-01-01

A component of fusion that is very important but quite difficult to evaluate is the incomplete fusion (ICF), in which only a part of the nucleus fuses with the target. ICF occurs together with the usual complete fusion (CF), in which the whole projectile fuses or all the projectile fragments after breakup fuse with the target nucleus. The ICF leads to the flux removal from the fusion channel and its calculation is essential for a comprehensive description of the fusion process. In the present work, a recently developed method of calculating the ICF cross-section (σ ICF ) is used in a novel way to disentangle the ICF effect on the fusion process from those due to breakup couplings. The total fusion cross-section σ TF and σ ICF for the 6 Li + 232 Th system are calculated at energies above and below the Coulomb barrier, where the measured fusion-fission data is available

Mesenchymal Stem Cells from Patients with Rheumatoid Arthritis Display Impaired Function in Inhibiting Th17 Cells

Directory of Open Access Journals (Sweden)

Yue Sun

2015-01-01

Full Text Available Mesenchymal stem cells (MSCs possess multipotent and immunomodulatory properties and are suggested to be involved in the pathogenesis of immune-related diseases. This study explored the function of bone marrow MSCs from rheumatoid arthritis (RA patients, focusing on immunomodulatory effects. RA MSCs showed decreased proliferative activity and aberrant migration capacity. No significant differences were observed in cytokine profiles between RA and control MSCs. The effects of RA MSCs on proliferation of peripheral blood mononuclear cells (PBMCs and distribution of specific CD4+ T cell subtypes (Th17, Treg, and Tfh cells were investigated. RA MSCs appeared to be indistinguishable from controls in suppressing PBMC proliferation, decreasing the proportion of Tfh cells, and inducing the polarization of Treg cells. However, the capacity to inhibit Th17 cell polarization was impaired in RA MSCs, which was related to the low expression of CCL2 in RA MSCs after coculture with CD4+ T cells. These findings indicated that RA MSCs display defects in several important biological activities, especially the capacity to inhibit Th17 cell polarization. These functionally impaired MSCs may contribute to the development of RA disease.

Promotional role of Li4Ti5O12 as polysulfide adsorbent and fast Li+ conductor on electrochemical performances of sulfur cathode

Science.gov (United States)

Zeng, Tianbiao; Hu, Xuebu; Ji, Penghui; Shang, Biao; Peng, Qimeng; Zhang, Yaoyao; Song, Ruiqiang

2017-08-01

Lithium-sulfur (Li-S) batteries attract much attention due to its high specific capacity and energy density compared to lithium-ion batteries (LiBs). Herein, a novel composite named as (void/nano-Li4Ti5O12 pieces)@C [(v/n-L)@C] was designed and prepared as a sulfur host. Spinel Li4Ti5O12 here as a multifunctional additive played as polysulfide adsorbent agent and fast Li+ conductor, and carbon shell was designed as electronic conductor, as well as volume barrier to limit the volume expansion caused by sulfur. As-prepared (S/nano-Li4Ti5O12 pieces)@C [(S/n-L)@C] are core-shell spheres, which are about 200 nm in size. Nano-Li4Ti5O12 and sulfur were coated by the outer carbon shell with a thickness of about 20 nm. The experimental results show that electrochemical performances of (S/n-L)@C cathode were enhanced effectively compared to S@C cathode. At 0.5C and 1C, the discharge capacity of (S/n-L)@C was 33.5% and 40.1% higher than that of S@C at 500th cycle. Even at 2C, its capacity reached 600.9 mAh g-1 at 1000th cycle. Li+ conductivity of (S/n-L)@C was one order of magnitude higher than that of S@C, which was reach to 2.55 × 10-8 S cm-1. The experiment results indicate Li4Ti5O12 plays a promotional role on electrochemical performances of sulfur cathode, especially for stable cycling performance and high rate performance.

Dynamic polarizabilities and Van der Waals coefficients for alkali atoms Li, Na and alkali dimer molecules Li2, Na2 and NaLi

Science.gov (United States)

Mérawa, M.; Dargelos, A.

1998-07-01

The present paper gives an account of investigations of the polarizability of the alkali atoms Li, Na, diatomics homonuclear and heteronuclear Li2, Na2 and NaLi at SCF (Self Consistent Field) level of approximation and at correlated level, using a time Time-Dependent Gauge Invariant method (TDGI). Our static polarizability values agree with the best experimental and theoretical determinations. The Van der Waals C6 coefficients for the atom-atom, atom-dimer and dimer-dimer interactions have been evaluated. Les polarisabilités des atomes alcalins Li, Na, et des molécules diatomiques homonucléaires et hétéronucléaire Li2, Na2 et NaLi, ont été calculées au niveau SCF (Self Consistent Field) et au niveau corrélé à partir d'une méthode invariante de jauge dépendante du temps(TDGI). Nos valeurs des polarisabilités statiques sont en accord avec les meilleurs déterminations expérimentales et théoriques. Les coefficients C6 de Van de Waals pour les interactions atome-atome, atome-dimère et dimère-dimère ont également été évalués.

Comparison of IRT Likelihood Ratio Test and Logistic Regression DIF Detection Procedures

Science.gov (United States)

Atar, Burcu; Kamata, Akihito

2011-01-01

The Type I error rates and the power of IRT likelihood ratio test and cumulative logit ordinal logistic regression procedures in detecting differential item functioning (DIF) for polytomously scored items were investigated in this Monte Carlo simulation study. For this purpose, 54 simulation conditions (combinations of 3 sample sizes, 2 sample…

Methodological issues regarding power of classical test theory (CTT and item response theory (IRT-based approaches for the comparison of patient-reported outcomes in two groups of patients - a simulation study

Directory of Open Access Journals (Sweden)

Boyer François

2010-03-01

Full Text Available Abstract Background Patients-Reported Outcomes (PRO are increasingly used in clinical and epidemiological research. Two main types of analytical strategies can be found for these data: classical test theory (CTT based on the observed scores and models coming from Item Response Theory (IRT. However, whether IRT or CTT would be the most appropriate method to analyse PRO data remains unknown. The statistical properties of CTT and IRT, regarding power and corresponding effect sizes, were compared. Methods Two-group cross-sectional studies were simulated for the comparison of PRO data using IRT or CTT-based analysis. For IRT, different scenarios were investigated according to whether items or person parameters were assumed to be known, to a certain extent for item parameters, from good to poor precision, or unknown and therefore had to be estimated. The powers obtained with IRT or CTT were compared and parameters having the strongest impact on them were identified. Results When person parameters were assumed to be unknown and items parameters to be either known or not, the power achieved using IRT or CTT were similar and always lower than the expected power using the well-known sample size formula for normally distributed endpoints. The number of items had a substantial impact on power for both methods. Conclusion Without any missing data, IRT and CTT seem to provide comparable power. The classical sample size formula for CTT seems to be adequate under some conditions but is not appropriate for IRT. In IRT, it seems important to take account of the number of items to obtain an accurate formula.

Decommissioning of the research nuclear reactor IRT-M and problems connected with radioactive waste

International Nuclear Information System (INIS)

Abramidze, S.P.; Katamadze, N.M.; Kiknadze, G.G.; Saralidze, Z.K.

2000-01-01

The nuclear research reactor IRT-2000 is described, along with modifications and upgrades made over the past three decades. Considerations are outlined which followed a decision to shut-down the reactor and to dismantle it. (author)

Structural versus electronic distortions of symmetry-broken IrTe$_2$

OpenAIRE

Kim, Hyo Sung; Kim, Tae-Hwan; Yang, Junjie; Cheong, Sang-Wook; Yeom, Han Woong

2014-01-01

We investigate atomic and electronic structures of the intriguing low temperature phase of IrTe2 using high-resolution scanning tunneling microscopy and spectroscopy. We confirm various stripe superstructures such as $\\times$3, $\\times$5, and $\\times$8. The strong vertical and lateral distortions of the lattice for the stripe structures are observed in agreement with recent calculations. The spatial modulations of electronic density of states are clearly identified as separated from the struc...

Electrochemical studies on electrospun Li(Li1/3Ti5/3)O4 grains as an anode for Li-ion batteries

International Nuclear Information System (INIS)

Wu Yongzhi; Reddy, M.V.; Chowdari, B.V.R.; Ramakrishna, S.

2012-01-01

Highlights: ► We report (Li(Li 1/3 Ti 5/3 )O 4 ) (LTO) obtained via electrospinning and followed by heat treatment. ► Electrochemical studies on nano-LTO showed a reversible capacity of 165(±3) mAh g −1 and 78(±3) mAh g −1 at a current rate of 0.2 C and 10 C, respectively. ► Electrode kinetics studies of LTO were carried out the end of 380 cycle using GITT and EIS techniques. - Abstract: Li(Li 1/3 Ti 5/3 )O 4 or (Li 4 Ti 5 O 12 ) (LTO) grains are prepared via electrospinning a solution containing lithium acetate, titanium tetra(IV)-isopropoxide, polyvinyl acetate and acetic acid in N,N-dimethyl-formamide, followed by a subsequent sintering process. The structures and morphology were characterized by X-ray diffraction, scanning and transmission microscopy. Coin-type cells were assembled to test the electrochemical performance was evaluated using galvanostatic cycling at room temperature, in the cycling range, 1.0–2.8 V. The Li-cycling results showed characteristic discharge-charge plateaus at 1.55 and 1.8 V vs. Li/Li + , respectively. Electrospun LTO showed a reversible capacity of 165(±3) mAh g −1 at the end of 10th cycle at a current rate of 0.2 C. The later studies on rate capacities and cycling performance of LTO grains demonstrate good rate performance and long term cycling stability. Galvanostatic Intermittent Titration Technique (GITT) and Electrochemical Impedance Spectroscopy (EIS) studied were carried out at end of 381st and 382nd cycle to understand the electrode kinetics.

Conscientiousness at the workplace: Applying mixture IRT to investigate scalability and predictive validity

NARCIS (Netherlands)

Egberink, I.J.L.; Meijer, R.R.; Veldkamp, Bernard P.

2010-01-01

Mixture item response theory (IRT) models have been used to assess multidimensionality of the construct being measured and to detect different response styles for different groups. In this study a mixture version of the graded response model was applied to investigate scalability and predictive

Conscientiousness in the workplace : Applying mixture IRT to investigate scalability and predictive validity

NARCIS (Netherlands)

Egberink, I.J.L.; Meijer, R.R.; Veldkamp, B.P.

Mixture item response theory (IRT) models have been used to assess multidimensionality of the construct being measured and to detect different response styles for different groups. In this study a mixture version of the graded response model was applied to investigate scalability and predictive

Synthesize and electrochemical characterization of Mg-doped Li-rich layered Li[Li0.2Ni0.2Mn0.6]O2 cathode material

International Nuclear Information System (INIS)

Wang, Dan; Huang, Yan; Huo, Zhenqing; Chen, Li

2013-01-01

Highlights: • Layered Li[Li 0.2 Ni 0.2−x Mn 0.6−x Mg 2x ]O 2 (2x = 0, 0.01, 0.02, 0.05) were synthetized. • Li[Li 0.2 Ni 0.2−x Mn 0.6−x Mg 2x ]O 2 exhibit enhanced electrochemical properties. • The improved performance is attributed to enhanced structure stability. -- Abstract: Mg-doped Li[Li 0.2 Ni 0.2 Mn 0.6 ]O 2 as a Li-rich cathode material of lithium-ion batteries were prepared by co-precipitation method and ball-milling treatment using Mg(OH) 2 as a dopant. Scanning electron microscopy (SEM), ex situ X-ray powder diffraction (XRD), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvantatic charge/discharge were used to investigate the effect of Mg doping on structure and electrochemical performance. Compared with the bare material, Mg-doped materials exhibit better cycle stabilities and superior rate capabilities. Li[Li 0.2 Ni 0.195 Mn 0.595 Mg 0.01 ]O 2 displays a high reversible capacity of 226.5 mAh g −1 after 60 cycles at 0.1 C. The excellent cycle performance can be attributed to the improvement in structure stability, which is verified by XRD tests before and after 60 cycles. EIS results show that Mg doping decreases the charge-transfer resistance and enhances the reaction kinetics, which is considered to be the major factor for higher rate performance

Comparing the IRT Pre-equating and Section Pre-equating: A Simulation Study.

Science.gov (United States)

Hwang, Chi-en; Cleary, T. Anne

The results obtained from two basic types of pre-equatings of tests were compared: the item response theory (IRT) pre-equating and section pre-equating (SPE). The simulated data were generated from a modified three-parameter logistic model with a constant guessing parameter. Responses of two replication samples of 3000 examinees on two 72-item…

Detecting DIF in Polytomous Items Using MACS, IRT and Ordinal Logistic Regression

Science.gov (United States)

Elosua, Paula; Wells, Craig

2013-01-01

The purpose of the present study was to compare the Type I error rate and power of two model-based procedures, the mean and covariance structure model (MACS) and the item response theory (IRT), and an observed-score based procedure, ordinal logistic regression, for detecting differential item functioning (DIF) in polytomous items. A simulation…

The first critical experiment with a new type of fuel assemblies IRT-3M on the training reactor VR-I

International Nuclear Information System (INIS)

Matejka, Karel; Sklenka, Lubomir

1997-01-01

The paper 'The first critical experiment with a new type of fuel assemblies IRT-3M on training reactor VR-1 presents basic information about the replacement of fuel on the reactor VR-1 run on FJFI CVUT in Prague. In spring 1997 the IRT-2M fuel type used till then was replaced by the IRT-3M type. When the fuel was replaced, no change in its enrichment was made, i.e. its level remained as 36% 235 U. The replacement itself was carried out in tight co-operation with the Nuclear Research Institute Rez plc., as related to the operation of the research reactor LVR-15. The fuel replacement on the VR-I reactor is a part of the international program RERTR (Reduced Enrichment for Research and Test Reactors) in which the Czech Republic participates. (author)

IRT Item Parameter Recovery with Marginal Maximum Likelihood Estimation Using Loglinear Smoothing Models

Science.gov (United States)

Casabianca, Jodi M.; Lewis, Charles

2015-01-01

Loglinear smoothing (LLS) estimates the latent trait distribution while making fewer assumptions about its form and maintaining parsimony, thus leading to more precise item response theory (IRT) item parameter estimates than standard marginal maximum likelihood (MML). This article provides the expectation-maximization algorithm for MML estimation…

Synthesis and electrochemistry of cubic rocksalt Li-Ni-Ti-O compounds in the phase diagram of LiNiO{sub 2}-LiTiO{sub 2}-Li[Li{sub 1/3}Ti{sub 2/3}]O{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Zhang, Lianqi; Noguchi, Hideyuki; Li, Decheng; Muta, Takahisa; Wang, Xiaoqing; Yoshio, Masaki [Department of Applied Chemistry, Saga University, Saga 840-8052 (Japan); Taniguchi, Izumi [Department of Chemical Engineering, Tokyo Institute of Technology, 12-1, Ookayama-2, Meguro-ku, Tokyo 152-8552 (Japan)

2008-10-15

On the basis of extreme similarity between the triangle phase diagrams of LiNiO{sub 2}-LiTiO{sub 2}-Li[Li{sub 1/3}Ti{sub 2/3}]O{sub 2} and LiNiO{sub 2}-LiMnO{sub 2}-Li[Li{sub 1/3}Mn{sub 2/3}]O{sub 2}, new Li-Ni-Ti-O series with a nominal composition of Li{sub 1+z/3}Ni{sub 1/2-z/2}Ti{sub 1/2+z/6}O{sub 2} (0 {<=} z {<=} 0.5) was designed and attempted to prepare via a spray-drying method. XRD identified that new Li-Ni-Ti-O compounds had cubic rocksalt structure, in which Li, Ni and Ti were evenly distributed on the octahedral sites in cubic closely packed lattice of oxygen ions. They can be considered as the solid solution between cubic LiNi{sub 1/2}Ti{sub 1/2}O{sub 2} and Li[Li{sub 1/3}Ti{sub 2/3}]O{sub 2} (high temperature form). Charge-discharge tests showed that Li-Ni-Ti-O compounds with appropriate compositions could display a considerable capacity (more than 80 mAh g{sup -1} for 0.2 {<=} z {<=} 0.27) at room temperature in the voltage range of 4.5-2.5 V and good electrochemical properties within respect to capacity (more than 150 mAh g{sup -1} for 0 {<=} z {<=} 0.27), cycleability and rate capability at an elevated temperature of 50 C. These suggest that the disordered cubic structure in some cases may function as a good host structure for intercalation/deintercalation of Li{sup +}. A preliminary electrochemical comparison between Li{sub 1+z/3}Ni{sub 1/2-z/2}Ti{sub 1/2+z/6}O{sub 2} (0 {<=} z {<=} 0.5) and Li{sub 6/5}Ni{sub 2/5}Ti{sub 2/5}O{sub 2} indicated that charge-discharge mechanism based on Ni redox at the voltage of >3.0 V behaved somewhat differently, that is, Ni could be reduced to +2 in Li{sub 1+z/3}Ni{sub 1/2-z/2}Ti{sub 1/2+z/6}O{sub 2} while +3 in Li{sub 6/5}Ni{sub 2/5}Ti{sub 2/5}O{sub 2}. Reduction of Ti{sup 4+} at a plateau of around 2.3 V could be clearly detected in Li{sub 1+z/3}Ni{sub 1/2-z/2}Ti{sub 1/2+z/6}O{sub 2} with 0.27 {<=} z {<=} 0.5 at 50 C after a deep charge associated with charge compensation from oxygen ion during initial cycle

Finite Mixture Multilevel Multidimensional Ordinal IRT Models for Large Scale Cross-Cultural Research

Science.gov (United States)

de Jong, Martijn G.; Steenkamp, Jan-Benedict E. M.

2010-01-01

We present a class of finite mixture multilevel multidimensional ordinal IRT models for large scale cross-cultural research. Our model is proposed for confirmatory research settings. Our prior for item parameters is a mixture distribution to accommodate situations where different groups of countries have different measurement operations, while…

Developing a Screening Inventory Reading Test (IRT for the Isfahanian Students of the First to Fifth Grade

Directory of Open Access Journals (Sweden)

Bijan Shafiei

2009-12-01

Full Text Available Background and aim: Reading is one of the most essential skills in this century. Reading disorders can cause several problems for the person who has reading disorder. Early assessment and diagnosis play an important role in treatment of this disorder. The main purpose of this study was to develope a screening inventory reading test (IRT for first to fifth grade student in Isfahan in order to early diagnosis of reading disorder.Materials and Methods: The test, consisting of 100 words context and four comprehension questions, named Inventory Reading Test (IRT, was evaluated by several speech therapists. It was standardized by testing on one thousand boys and girls, 200 students in every grade, that were selected through a multi-stage random sampling method. Test was performed on two other groups, a normal and a reading-disordered.Results: Scores of reading accuracy and velocity were highly correlated with the test total score. Test reliability was calculated as 0.77 by Cronbach`s alpha measure. There was significant difference between two groups mean score (p=0.01.Conclusion: IRT seems to be an appropriate tool for screening reading disorder of first to fifth grade students.

Using a Linear Regression Method to Detect Outliers in IRT Common Item Equating

Science.gov (United States)

He, Yong; Cui, Zhongmin; Fang, Yu; Chen, Hanwei

2013-01-01

Common test items play an important role in equating alternate test forms under the common item nonequivalent groups design. When the item response theory (IRT) method is applied in equating, inconsistent item parameter estimates among common items can lead to large bias in equated scores. It is prudent to evaluate inconsistency in parameter…

Future development of the research nuclear reactor IRT-2000 in Sofia

International Nuclear Information System (INIS)

Apostolov, T.G.

1999-01-01

The present paper presents a short description of the research reactor IRT-2000 Sofia, started in 1961 and operated for 28 years. Some items are considered, connected to the improvements made in the contemporary safety requirements and the unrealized project for modernization to 5 MW. Proposals are considered for reconstruction of reactor site to a 'reactor of low power' for education purposes and as a basis for the country's nuclear technology development. (author)

Re-building Daniell Cell with a Li-ion exchange Film

Science.gov (United States)

Dong, Xiaoli; Wang, Yonggang; Xia, Yongyao

2014-11-01

Daniell cell (i.e. Zn-Cu battery) is widely used in chemistry curricula to illustrate how batteries work, although it has been supplanted in the late 19th century by more modern battery designs because of Cu2+-crossover-induced self-discharge and un-rechargeable characteristic. Herein, it is re-built by using a ceramic Li-ion exchange film to separate Cu and Zn electrodes for preventing Cu2+-crossover between two electrodes. The re-built Zn-Cu battery can be cycled for 150 times without capacity attenuation and self-discharge, and displays a theoretical energy density of 68.3 Wh kg-1. It is more important that both electrodes of the battery are renewable, reusable, low toxicity and environmentally friendly. Owing to these advantages mentioned above, the re-built Daniell cell can be considered as a promising and green stationary power source for large-scale energy storage.

Re-building Daniell cell with a Li-ion exchange film.

Science.gov (United States)

Dong, Xiaoli; Wang, Yonggang; Xia, Yongyao

2014-11-05

Daniell cell (i.e. Zn-Cu battery) is widely used in chemistry curricula to illustrate how batteries work, although it has been supplanted in the late 19th century by more modern battery designs because of Cu(2+)-crossover-induced self-discharge and un-rechargeable characteristic. Herein, it is re-built by using a ceramic Li-ion exchange film to separate Cu and Zn electrodes for preventing Cu(2+)-crossover between two electrodes. The re-built Zn-Cu battery can be cycled for 150 times without capacity attenuation and self-discharge, and displays a theoretical energy density of 68.3 Wh kg(-1). It is more important that both electrodes of the battery are renewable, reusable, low toxicity and environmentally friendly. Owing to these advantages mentioned above, the re-built Daniell cell can be considered as a promising and green stationary power source for large-scale energy storage.

Distinguishing Continuous and Discrete Approaches to Multilevel Mixture IRT Models: A Model Comparison Perspective

Science.gov (United States)

Zhu, Xiaoshu

2013-01-01

The current study introduced a general modeling framework, multilevel mixture IRT (MMIRT) which detects and describes characteristics of population heterogeneity, while accommodating the hierarchical data structure. In addition to introducing both continuous and discrete approaches to MMIRT, the main focus of the current study was to distinguish…

Circular displays: control/display arrangements and stereotype strength with eight different display locations.

Science.gov (United States)

Chan, Alan H S; Hoffmann, Errol R

2015-01-01

Two experiments are reported that were designed to investigate control/display arrangements having high stereotype strengths when using circular displays. Eight display locations relative to the operator and control were tested with rotational and translational controls situated on different planes according to the Frame of Reference Transformation Tool (FORT) model of Wickens et al. (2010). (Left. No, Right! Development of the Frame of Reference Transformation Tool (FORT), Proceedings of the Human Factors and Ergonomics Society 54th Annual Meeting, 54: 1022-1026). In many cases, there was little effect of display locations, indicating the importance of the Worringham and Beringer (1998. Directional stimulus-response compatibility: a test of three alternative principles. Ergonomics, 41(6), 864-880) Visual Field principle and an extension of this principle for rotary controls (Hoffmann and Chan (2013). The Worringham and Beringer 'visual field' principle for rotary controls. Ergonomics, 56(10), 1620-1624). The initial indicator position (12, 3, 6 and 9 o'clock) had a major effect on control/display stereotype strength for many of the six controls tested. Best display/control arrangements are listed for each of the different control types (rotational and translational) and for the planes on which they are mounted. Data have application where a circular display is used due to limited display panel space and applies to space-craft, robotics operators, hospital equipment and home appliances. Practitioner Summary: Circular displays are often used when there is limited space available on a control panel. Display/control arrangements having high stereotype strength are listed for four initial indicator positions. These arrangements are best for design purposes.

Tests to control the power distribution in the IRT-2,000 reactor

International Nuclear Information System (INIS)

Filipcuk, E.V.; Potapenko, P.T.; Krjukov, A.P.; Trofimov, A.P.; Kosilov, A.N.; Nebojan, V.T.; Timochin, E.S.

1976-01-01

Results of the investigations of a few structures of such control systems carried out with the help of the IRT 2,000 MIFI reactor in the years 1973/74 are presented in the present work. Within the framework of this study, the successful test of using the transmitter of the direct loading in equipment to control the neutron field was carried out. (orig./TK) [de

Future development of the research nuclear reactor IRT-2000 in Sofia

Energy Technology Data Exchange (ETDEWEB)

Apostolov, T.G. [Institute for Nuclear Research and Nuclear Energy, BAS, Sofia (Bulgaria)

1999-07-01

The present paper presents a short description of the research reactor IRT-2000 Sofia, started in 1961 and operated for 28 years. Some items are considered, connected to the improvements made in the contemporary safety requirements and the unrealized project for modernization to 5 MW. Proposals are considered for reconstruction of reactor site to a 'reactor of low power' for education purposes and as a basis for the country's nuclear technology development. (author)

Experiments in power distribution control on the IRT-2000 reactor

International Nuclear Information System (INIS)

Filipchuk, E.V.; Potapenko, P.T.; Trofimov, A.P.; Kosilov, A.N.; Neboyan, V.T.; Timokhin, E.S.

1975-01-01

The results from the experimental investigations of a system for regulating the neutron field on a research reactor IRT-2000 are shown. The right of such experiments on a reactor with a little active zone is substantiated. A successful attempt was made in this work to apply primary elements of straight charging in the neutron field regulating system. A system with independent instrumentally local regulators, a system with hard cross connections and a structure with a ''floating'' installation are studied. Serial common industrial regulators BRT-2 were used

Polymer-ionic liquid ternary systems for Li-battery electrolytes: Molecular dynamics studies of LiTFSI in a EMIm-TFSI and PEO blend

Energy Technology Data Exchange (ETDEWEB)

Costa, Luciano T., E-mail: ltcosta@id.uff.br [Instituto de Química-Departamento de Físico-Química, Universidade Federal Fluminense, Outeiro de São João Batista s/n CEP, 24020-150 Niterói, Rio de Janeiro (Brazil); Sun, Bing; Jeschull, Fabian; Brandell, Daniel [Department of Chemistry—Ångström Laboratory, Uppsala University, P.O. Box 538, SE-751 21 Uppsala (Sweden)

2015-07-14

This paper presents atomistic molecular dynamics simulation studies of lithium bis(trifluoromethane)sulfonylimide (LiTFSI) in a blend of 1-ethyl-3-methylimidazolium (EMIm)-TFSI and poly(ethylene oxide) (PEO), which is a promising electrolyte material for Li- and Li-ion batteries. Simulations of 100 ns were performed for temperatures between 303 K and 423 K, for a Li:ether oxygen ratio of 1:16, and for PEO chains with 26 EO repeating units. Li{sup +} coordination and transportation were studied in the ternary electrolyte system, i.e., PEO{sub 16}LiTFSI⋅1.0 EMImTFSI, by applying three different force field models and are here compared to relevant simulation and experimental data. The force fields generated significantly different results, where a scaled charge model displayed the most reasonable comparisons with previous work and overall consistency. It is generally seen that the Li cations are primarily coordinated to polymer chains and less coupled to TFSI anion. The addition of EMImTFSI in the electrolyte system enhances Li diffusion, associated to the enhanced TFSI dynamics observed when increasing the overall TFSI anion concentration in the polymer matrix.

Using Eye-Tracking Data and Mouse Cursor Location To Examine Visual Alerting in a Multi-Display Environment

Science.gov (United States)

2014-07-23

displays. Border alerts were similar in width and colour but surrounded the entire perimeter of the display. Secondary task The secondary task...cognitive processes. Cognitive Psychology , 8, 441-480. Li, G., Wang, W., Li, S., Cheng, B., & Green, P. (2014). Effectiveness of flashing brake and hazard...T., Engbert, R., & Henderson, J. (2010). CRISP: A computational model of fixation durations in scene viewing. Psychological Review, 117(2), 382-405

Quaternary system LiF-LiCl-LiVO3-Li2MoO4

International Nuclear Information System (INIS)

Anipchenko, B.V.; Garkushin, I.K.

2000-01-01

Interactions in the LiF-LiCl-LiVO 3 -Li 2 MoO 4 system are studied by differential thermal analysis. Rate of heating/cooling of the samples comprised 15 Grad/min, mass of sample composed 0.2 g. The system was investigated in the 300-650 Deg C range. X-ray diffraction method was used for determination of purity of the reagents. Composition and temperature of quaternary component eutectics are determined: 16.5 mol. % of LiF, 47.0 mol. % of LiCl, 28.8 mol. % of LiVO 3 , 7.6 mol. % of Li 2 MoO 4 ; 387 Deg C. Mean value of melting enthalpy of quaternary eutectics mixture in the LiF-LiCl-LiVO 3 -Li 2 MoO 4 system on the results of the tests was in the range of 222 kJ/kg [ru

IRT-LR-DIF with Estimation of the Focal-Group Density as an Empirical Histogram

Science.gov (United States)

Woods, Carol M.

2008-01-01

Item response theory-likelihood ratio-differential item functioning (IRT-LR-DIF) is used to evaluate the degree to which items on a test or questionnaire have different measurement properties for one group of people versus another, irrespective of group-mean differences on the construct. Usually, the latent distribution is presumed normal for both…

Pretest-Posttest-Posttest Multilevel IRT Modeling of Competence Growth of Students in Higher Education in Germany

NARCIS (Netherlands)

Schmidt, Susanne; Zlatkin-Troitschanskaia, Olga; Fox, Gerardus J.A.

2016-01-01

Longitudinal research in higher education faces several challenges. Appropriate methods of analyzing competence growth of students are needed to deal with those challenges and thereby obtain valid results. In this article, a pretest-posttest-posttest multivariate multilevel IRT model for repeated

Analysis of Charge Transfer for in Situ Li Intercalated Carbon Nanotubes

KAUST Repository

Rana, Kuldeep

2012-05-24

Vertically aligned carbon nanotube (VA-CNT) arrays have been synthesized with lithium (Li) intercalation through an alcohol-catalyzed chemical vapor deposition technique by using a Li-containing catalyst. Scanning electron microscopy images display that synthesized carbon nanotubes (CNTs) are dense and vertically aligned. The effect of the Li-containing catalyst on VA-CNTs has been studied by using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electron energy loss spectroscopy (EELS). XPS results show the change in binding energy of Li 1s and C 1s peaks, which indicates that Li is inserted in VA-CNTs during growth. Analysis of Raman spectra reveals that the G-band profile of CNTs synthesized with the Li-containing catalyst is shifted, suggesting an electronic interaction between Li and neighboring C atoms of the CNTs. The EELS spectra of the C K edge and Li K edge from CNTs also confirmed that Li is inserted into CNTs during synthesis. We have performed ab inito calculations based on density functional theory for a further understanding of the structural and electronic properties of Li intercalated CNTs, especially addressing the controversial charge-transfer state between Li and C. © 2012 American Chemical Society.

Analysis of Charge Transfer for in Situ Li Intercalated Carbon Nanotubes

KAUST Repository

Rana, Kuldeep; Kucukayan-Dogu, Gokce; Sen, H. Sener; Boothroyd, Chris; Gulseren, Oguz; Bengu, Erman

2012-01-01

Vertically aligned carbon nanotube (VA-CNT) arrays have been synthesized with lithium (Li) intercalation through an alcohol-catalyzed chemical vapor deposition technique by using a Li-containing catalyst. Scanning electron microscopy images display that synthesized carbon nanotubes (CNTs) are dense and vertically aligned. The effect of the Li-containing catalyst on VA-CNTs has been studied by using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electron energy loss spectroscopy (EELS). XPS results show the change in binding energy of Li 1s and C 1s peaks, which indicates that Li is inserted in VA-CNTs during growth. Analysis of Raman spectra reveals that the G-band profile of CNTs synthesized with the Li-containing catalyst is shifted, suggesting an electronic interaction between Li and neighboring C atoms of the CNTs. The EELS spectra of the C K edge and Li K edge from CNTs also confirmed that Li is inserted into CNTs during synthesis. We have performed ab inito calculations based on density functional theory for a further understanding of the structural and electronic properties of Li intercalated CNTs, especially addressing the controversial charge-transfer state between Li and C. © 2012 American Chemical Society.

Co-ordinate expression of Th1/Th2 phenotypes in maternal and fetal blood: evidence for a transplacental nexus.

Science.gov (United States)

Tse, Doris B; Young, Bruce K

2012-01-06

If maternal atopy and environmental exposure affect prenatal Th cell development, the maternal and fetal immune systems should display common Th1/Th2 phenotypes. To test this hypothesis, we studied maternal and neonatal blood samples from mothers with total serum IgE ordinate IFN-γ production from paired maternal and fetal mononuclear cells, accompanied by co-ordinate increases in activated CD4+CD69+ cells that display the CCR4+Th2 and CXCR3+ Th1 phenotypes. Maternal and fetal CD4+CXCR3+ T cells were subsequently identified as the major producers of IFN-γ. The data established that a transplacental nexus exists during normal pregnancy and that fetal Th cell responses may be biased by the maternal immune system.

Effect of display location on control-display stereotype strength for translational and rotational controls with linear displays.

Science.gov (United States)

Chan, Alan H S; Hoffmann, Errol R

2015-01-01

Experiments were designed to investigate the effects of control type and display location, relative to the operator, on the strength of control/display stereotypes. The Worringham and Beringer Visual Field principle and an extension of this principle for rotary controls (Hoffmann E.R., and Chan A.H.S. 2013). "The Worringham and Beringer 'Visual Field' Principle for Rotary Controls. Ergonomics." 56 (10): 1620-1624) indicated that, for a number of different control types (rotary and lever) on different planes, there should be no significant effect of the display location relative to the seated operator. Past data were surveyed and stereotype strengths listed. Experiments filled gaps where data are not available. Six different control types and seven display locations were used, as in the Frame of Reference Transformation Tool (FORT) model of Wickens et al. (Wickens, C.D., Keller, J.W., and Small, R.L. (2010). "Left. No, Right! Development of the Frame of Reference Transformation Tool (FORT)." Proceedings of the Human Factors and Ergonomics Society 54th Annual Meeting September 2010, 54: 1022-1026). Control/display arrangements with high stereotype strengths were evaluated yielding data for designers of complex control/display arrangements where the control and display are in different planes and for where the operator is moving. It was found possible to predict display/control arrangements with high stereotype strength, based on past data. Practitioner Summary: Controls and displays in complex arrangements need to have high compatibility. These experiments provide arrangements for six different controls (rotary and translational) and seven different display locations relative to the operator.

Parent Stars of Extrasolar Planets - XIV. Strong Evidence of Li Abundance Deficit

OpenAIRE

Gonzalez, Guillermo

2014-01-01

We report the results of our analysis of new high resolution spectra of 30 late-F to early-G dwarf field stars for the purpose of deriving their Li abundances. They were selected from the subsample of stars in the Valenti and Fischer compilation that are lacking detected planets. These new data serve to expand our comparison sample used to test whether stars with Doppler-detected giant planets display Li abundance anomalies. Our results continue to show that Li is deficient among stars with p...

Robust Scale Transformation Methods in IRT True Score Equating under Common-Item Nonequivalent Groups Design

Science.gov (United States)

He, Yong

2013-01-01

Common test items play an important role in equating multiple test forms under the common-item nonequivalent groups design. Inconsistent item parameter estimates among common items can lead to large bias in equated scores for IRT true score equating. Current methods extensively focus on detection and elimination of outlying common items, which…

In situ synthesized Li2S@porous carbon cathode for graphite/Li2S full cells using ether-based electrolyte

International Nuclear Information System (INIS)

Wang, Ning; Zhao, Naiqin; Shi, Chunsheng; Liu, Enzuo; He, Chunnian; He, Fang; Ma, Liying

2017-01-01

Graphical abstract: A facile method is proposed to prepare lithium sulfide@porous carbon composites (Li 2 S@PC) by in-situ reaction of lithium sulfate (Li 2 SO 4 ) and the pyrolytic carbon from glucose. We assembled graphite-Li 2 S@PC full-cells using the obtained Li 2 S@PC composites as the cathode, graphite as the anode and DOL/DME with LiNO 3 additive as the electrolyte. Display Omitted -- Highlights: •A simple synthesis method was proposed to form Li 2 S@porous carbon composites. •Graphite-Li 2 S full-cells were constructed in DME-based electrolyte. •A novel method was proposed to activate the full cells. -- Abstract: Lithium-sulfur (Li-S) batteries have been recognized as one of the promising next-generation energy storage devices owing to their high energy density, low cost and eco-friendliness. As for cathode’s performance, the main challenges for developing highly-efficient and long-life Li-S batteries are to retard the polysulfides diffusion into electrolyte and the reaction with metallic lithium (Li). Especially, the safety issues, derived from metallic Li in anode, must be overcome. Herein, we fabricated lithium sulfide@porous carbon composites (Li 2 S@PC) by an in-situ reaction between the lithium sulfate (Li 2 SO 4 ) and the pyrolytic carbon from glucose. The nanosized Li 2 S particles were uniformly distributed in the carbon matrix, which not only significantly improve electronic conductivity of the electrode but also effectively trap the dissolved polysulfides. Furthermore, on the basis of the graphite’s electrochemical features in ether-based electrolyte, we assembled graphite-Li 2 S@PC full cells using the obtained Li 2 S@PC composites as the cathode, graphite as the anode and the DOL/DME with LiNO 3 additive as the electrolyte. A unique strategy was proposed to activate the full-cells in descending order using constant voltage and current to charge the cut-off voltage. This Li-S full cell exhibits stable cycling performance at 0.5 C over

Synthesis and characterization of Li2FeP2O7/C nanocomposites as cathode materials for Li-ion batteries

International Nuclear Information System (INIS)

Du, Juan; Jiao, Lifang; Wu, Qiong; Liu, Yongchang; Zhao, Yanping; Guo, Lijing; Wang, Yijing; Yuan, Huatang

2013-01-01

Highlights: • Li 2 FeP 2 O 7 /C were prepared by a simple solid-state reaction. • Carbon coating and reducing particle size are adopted to improve the discharge capacity. • The detailed study about the electrochemical properties of Li 2 FeP 2 O 7 is scarce. • Li 2 FeP 2 O 7 /C show superior electrochemical properties. -- Abstract: The pristine Li 2 FeP 2 O 7 and Li 2 FeP 2 O 7 /C nanocomposites with different content of carbon have been successfully synthesized via a simple solid-state reaction, using cheap glucose as carbon source. XRD and EDS patterns demonstrate the high purity of the products. SEM images exhibit that the size of the particles is about 50–500 nm. Electrochemical measurements reveal that carbon coating and reducing particle size significantly enhance the electrochemical performances of Li 2 FeP 2 O 7 . Particularly, the Li 2 FeP 2 O 7 /C sample with a carbon content of 4.88 wt.% displays the best performance with a specific discharge capacity of 103.1 mAh g −1 at 0.1 C, which is 93.7% of its one-electron theoretical capacity, meaning 110 mAh g −1 . Meanwhile, it shows favorable cycling stability and excellent rate performance, indicating its potential applicability in Li-ion batteries in the long term

Attainable high capacity in Li-excess Li-Ni-Ru-O rock-salt cathode for lithium ion battery

Science.gov (United States)

Wang, Xingbo; Huang, Weifeng; Tao, Shi; Xie, Hui; Wu, Chuanqiang; Yu, Zhen; Su, Xiaozhi; Qi, Jiaxin; Rehman, Zia ur; Song, Li; Zhang, Guobin; Chu, Wangsheng; Wei, Shiqiang

2017-08-01

Peroxide structure O2n- has proven to appear after electrochemical process in many lithium-excess precious metal oxides, representing extra reversible capacity. We hereby report construction of a Li-excess rock-salt oxide Li1+xNi1/2-3x/2Ru1/2+x/2O2 electrode, with cost effective and eco-friendly 3d transition metal Ni partially substituting precious 4d transition metal Ru. It can be seen that O2n- is formed in pristine Li1.23Ni0.155Ru0.615O2, and stably exists in subsequent cycles, enabling discharge capacities to 295.3 and 198 mAh g-1 at the 1st/50th cycle, respectively. Combing ex-situ X-ray absorption near edge spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, high resolution transmission electron microscopy and electrochemical characterization, we demonstrate that the excellent electrochemical performance comes from both percolation network with disordered structure and cation/anion redox couples occurring in charge-discharge process. Li-excess and substitution of common element have been demonstrated to be a breakthrough for designing novel high performance commercial cathodes in rechargeable lithium ion battery field.

New tests of the common calibration context for ISO, IRTS, and MSX

Science.gov (United States)

Cohen, Martin

1997-01-01

The work carried out in order to test, verify and validate the accuracy of the calibration spectra provided to the Infrared Space Observatory (ISO), to the Infrared Telescope in Space (IRTS) and to the Midcourse Space Experiment (MSX) for external calibration support of instruments, is reviewed. The techniques, used to vindicate the accuracy of the absolute spectra, are discussed. The work planned for comparing far infrared spectra of Mars and some of the bright stellar calibrators with long wavelength spectrometer data are summarized.

Impact of incorporation of chromium on electrochemical properties of LiFePO4/C for Li-ion batteries

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Naik Amol

2015-12-01

Full Text Available LiFe0.95Cr0.05PO4/C was successfully synthesized by one-step solid-state reaction using a single mode microwave reactor. The effect of incorporation of chromium on LiFePO4 lattice parameters was systematically investigated by X-ray diffraction. Surface analysis was done by scanning electron microscopy and transmission electron microscopy. The ratio of amorphous to graphitic carbon was determined from Raman spectroscopic data. The influence of chromium incorporation on electrochemical properties was studied by recording charge/discharge cycles combined with electrochemical impedance spectroscopy (EIS and cyclic voltammetry. It was found that Cr incorporation significantly enhanced the electrochemical performance of LiFePO4 at all current densities up to 10 C. LiFe0.95Cr0.05PO4/C prepared exhibited the best performance with an initial specific discharge capacity of 157.7, 144.8, 138.3, 131.0, 124.1 and 111.1 mAh·g−1 at 0.1 C, 0.5 C, 1.0 C, 2.0 C, 5 C and 10 C, respectively. The doped sample displayed excellent capacity retention, which was substantially superior than that of pristine LiFePO4/C at a higher current rate.

Comparison of LiVPO4F to Li4Ti5O12 as anode materials for lithium-ion batteries.

Science.gov (United States)

Ma, Rui; Shao, Lianyi; Wu, Kaiqiang; Shui, Miao; Wang, Dongjie; Pan, Jianguo; Long, Nengbing; Ren, Yuanlong; Shu, Jie

2013-09-11

In this paper, we reported on a comparison of LiVPO4F to Li4Ti5O12 as anode materials for lithium-ion batteries. Combined with powder X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, galvanostatic discharge/charge tests and in situ X-ray diffraction technologies, we explore and compare the insertion/extraction mechanisms of LiVPO4F based on the V3+/V2+/V+ redox couples and Li4Ti5O12 based on the Ti4+/Ti3+ redox couple cycled in 1.0-3.0 V and 0.0-3.0 V. The electrochemical results indicate that both LiVPO4F and Li4Ti5O12 are solid electrolyte interphase free materials in 1.0-3.0 V. The insertion/extraction mechanisms of LiVPO4F and Li4Ti5O12 are similar with each other in 1.0-3.0 V as proved by in situ X-ray diffraction. It also demonstrates that both samples possess stable structure in 0.0-3.0 V. Additionally, the electrochemical performance tests of LiVPO4F and Li4Ti5O12 indicate that both samples cycled in 0.0-3.0 V exhibit much higher capacities than those cycled in 1.0-3.0 V but display worse cycle performance. The rate performance of Li4Ti5O12 far exceeds that of LiVPO4F in the same electrochemical potential window. In particular, the capacity retention of Li4Ti5O12 cycled in 1.0-3.0 V is as high as 98.2% after 20 cycles. By contrast, Li4Ti5O12 is expected to be a candidate anode material considering its high working potential, structural zero-strain property, and excellent cycle stability and rate performance.

Electrochemical Behavior of LiBr, LiI, and Li2Se in LiCl Molten Salt

International Nuclear Information System (INIS)

Choi, In Kyu; Do, Jae Bum; Hong, Sun Seok; Seo, Chung Seok

2006-03-01

The effect of fission products on the electrolytic reduction of uranium oxide has been studied. It has been reported that volatile fission products, such as Br, I, and Se, react with Li metal which is a reductant in the process to give LiBr, LiI, and Li 2 Se. These compounds are dissociated as corresponding anions and cations in the LiCl molten salt at 650 .deg. C. In this experiment, oxidation and reduction reaction of 3wt% of each compound in LiCl molten salt were investigated by cyclic voltammetry. For LiBr, redox reactions of cation and anion were reversible, while redox reactions of Li + and I - were irreversible. For Li 2 Se, about half of the produced Li metal was disappeared at the cathode and two anodic current curves were appeared. After the cyclic voltammetric measurements for each compound, chronopotentiometric experiment was carried out for one hour with 100 - 400 mA. After the electrolysis, no compounds gave Li metal in the porous MgO filter in which Li metal was produced at the cathode. However, LiCl salt was covered with Br 2 for LiBr electrolysis. Dark red color of Br 2 was easily removed by water. For LiI electrolysis, salt gave black color and I 2 was deposited on the Pt anode. For Li 2 Se electrolysis, black fine powders were precipitated in the salt. After the separation and dryness of the precipitates, it was analyzed with XRD and it turned out PtSe 2 . From the electrochemical experimental results, it was concluded that these compounds may affect the electrolytic reduction process of uranium oxide in the spent fuel

Oxygen Vacancies and Stacking Faults Introduced by Low-Temperature Reduction Improve the Electrochemical Properties of Li2MnO3 Nanobelts as Lithium-Ion Battery Cathodes.

Science.gov (United States)

Sun, Ya; Cong, Hengjiang; Zan, Ling; Zhang, Youxiang

2017-11-08

Among the Li-rich layered oxides Li 2 MnO 3 has significant theoretical capacity as a cathode material for Li-ion batteries. Pristine Li 2 MnO 3 generally has to be electrochemically activated in the first charge-discharge cycle which causes very low Coulombic efficiency and thus deteriorates its electrochemical properties. In this work, we show that low-temperature reduction can produce a large amount of structural defects such as oxygen vacancies, stacking faults, and orthorhombic LiMnO 2 in Li 2 MnO 3 . The Rietveld refinement analysis shows that, after a reduction reaction with stearic acid at 340 °C for 8 h, pristine Li 2 MnO 3 changes into a Li 2 MnO 3 -LiMnO 2 (0.71/0.29) composite, and the monoclinic Li 2 MnO 3 changes from Li 2.04 Mn 0.96 O 3 in the pristine Li 2 MnO 3 (P-Li 2 MnO 3 ) to Li 2.1 Mn 0.9 O 2.79 in the reduced Li 2 MnO 3 (R-Li 2 MnO 3 ), indicating the production of a large amount of oxygen vacancies in the R-Li 2 MnO 3 . High-resolution transmission electron microscope images show that a high density of stacking faults is also introduced by the low-temperature reduction. When measured as a cathode material for Li-ion batteries, R-Li 2 MnO 3 shows much better electrochemical properties than P-Li 2 MnO 3 . For example, when charged-discharged galvanostatically at 20 mA·g -1 in a voltage window of 2.0-4.8 V, R-Li 2 MnO 3 has Coulombic efficiency of 77.1% in the first charge-discharge cycle, with discharge capacities of 213.8 and 200.5 mA·h·g -1 in the 20th and 30th cycles, respectively. In contrast, under the same charge-discharge conditions, P-Li 2 MnO 3 has Coulombic efficiency of 33.6% in the first charge-discharge cycle, with small discharge capacities of 80.5 and 69.8 mA·h·g -1 in the 20th and 30th cycles, respectively. These materials characterizations, and electrochemical measurements show that low-temperature reduction is one of the effective ways to enhance the performances of Li 2 MnO 3 as a cathode material for Li-ion batteries.

Landslide Mapping and Characterization through Infrared Thermography (IRT: Suggestions for a Methodological Approach from Some Case Studies

Directory of Open Access Journals (Sweden)

William Frodella

2017-12-01

Full Text Available In this paper, the potential of Infrared Thermography (IRT as a novel operational tool for landslide surveying, mapping and characterization was tested and demonstrated in different case studies, by analyzing various types of instability processes (rock slide/fall, roto-translational slide-flow. In particular, IRT was applied, both from terrestrial and airborne platforms, in an integrated methodology with other geomatcs methods, such as terrestrial laser scanning (TLS and global positioning systems (GPS, for the detection and mapping of landslides’ potentially hazardous structural and morphological features (structural discontinuities and open fractures, scarps, seepage and moisture zones, landslide drainage network and ponds. Depending on the study areas’ hazard context, the collected remotely sensed data were validated through field inspections, with the purpose of studying and verifying the causes of mass movements. The challenge of this work is to go beyond the current state of the art of IRT in landslide studies, with the aim of improving and extending the investigative capacity of the analyzed technique, in the framework of a growing demand for effective Civil Protection procedures in landslide geo-hydrological disaster managing activities. The proposed methodology proved to be an effective tool for landslide analysis, especially in the field of emergency management, when it is often necessary to gather all the required information in dangerous environments as fast as possible, to be used for the planning of mitigation measures and the evaluation of hazardous scenarios. Advantages and limitations of the proposed method in the field of the explored applications were evaluated, as well as general operative recommendations and future perspectives.

ARPES and NMTO Wannier Orbital Theory of Li{sub 0.9}Mo{sub 6}O{sub 17}

Energy Technology Data Exchange (ETDEWEB)

Dudy, L. [Physikalisches Institut, Universitaet Wuerzburg, D- 97074 Wuerzburg (Germany); Allen, J.W. [University of Michigan, Ann Arbor, MI (United States); Denlinger, J.D. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); He, J. [Clemson University, Clemson, SC (United States); Greenblatt, M. [Rutgers University, Piscataway, NJ (United States); Haverkort, M.W. [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Dresden (Germany); Andersen, O.K.; Nohara, Y. [Max-Planck-Institut fuer Festkoerperphysik, Stuttgart (Germany)

2015-07-01

Li{sub 0.9}Mo{sub 6}O{sub 17} displays theoretically interesting metallic quasi-one dimensional (1D) behavior that is unusually robust against 3D crossover with decreasing temperature, and is characterized by a large value of anomalous exponent α∼ 0.6. We present very high resolution, low temperature (T=6K-30K) angle resolved photoemission spectroscopy (ARPES) of its band structure and Fermi surface (FS), analyzed with N-th order muffin tin orbital (NMTO) Wannier function band theory. We confirm a previous conclusion that LDA band theory is unusually successful, implying a small Hubbard U, and find in ARPES the dispersion and FS warping and splitting expected for predicted small and long range hoppings (t {sub perpendicular} {sub to} ∼ 10-15 meV) between chains.

Annual Quality Assurance Conference Files by Nicola Watson and Rui Li

Science.gov (United States)

26th Annual Quality Assurance Conference. Abstract: An Innovative Water Management Device for Online and Canister-based Thermal Desorption of Trace-level VVOCs in High Humidity Ambient Air by Nicola Watson and Rui Li

Lithium ion mobility in lithium phosphidosilicates: Crystal structure, {sup 7}Li, {sup 29}Si, and {sup 31}P MAS NMR spectroscopy, and impedance spectroscopy of Li{sub 8}SiP{sub 4} and Li{sub 2}SiP{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Toffoletti, Lorenzo; Landesfeind, Johannes; Klein, Wilhelm; Gasteiger, Hubert A.; Faessler, Thomas F. [Department of Chemistry, Technische Universitaet Muenchen, Lichtenbergstrasse 4, 85747, Garching bei Muenchen (Germany); Kirchhain, Holger; Wuellen, Leo van [Department of Physics, University of Augsburg, Universitaetsstrasse 1, 86159, Augsburg (Germany)

2016-12-05

The need to improve electrodes and Li-ion conducting materials for rechargeable all-solid-state batteries has drawn enhanced attention to the investigation of lithium-rich compounds. The study of the ternary system Li-Si-P revealed a series of new compounds, two of which, Li{sub 8}SiP{sub 4} and Li{sub 2}SiP{sub 2}, are presented. Both phases represent members of a new family of Li ion conductors that display Li ion conductivity in the range from 1.15(7) x 10{sup -6} Scm{sup -1} at 0 C to 1.2(2) x 10{sup -4} Scm{sup -1} at 75 C (Li{sub 8}SiP{sub 4}) and from 6.1(7) x 10{sup -8} Scm{sup -1} at 0 C to 6(1) x 10{sup -6} Scm{sup -1} at 75 C (Li{sub 2}SiP{sub 2}), as determined by impedance measurements. Temperature-dependent solid-state {sup 7}Li NMR spectroscopy revealed low activation energies of about 36 kJ mol{sup -1} for Li{sub 8}SiP{sub 4} and about 47 kJ mol{sup -1} for Li{sub 2}SiP{sub 2}. Both compounds were structurally characterized by X-ray diffraction analysis (single crystal and powder methods) and by {sup 7}Li, {sup 29}Si, and {sup 31}P MAS NMR spectroscopy. Both phases consist of tetrahedral SiP{sub 4} anions and Li counterions. Li{sub 8}SiP{sub 4} contains isolated SiP{sub 4} units surrounded by Li atoms, while Li{sub 2}SiP{sub 2} comprises a three-dimensional network based on corner-sharing SiP{sub 4} tetrahedra, with the Li ions located in cavities and channels. (copyright 2016 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Measuring Anxiety in Visually-Impaired People: A Comparison between the Linear and the Nonlinear IRT Approaches

Science.gov (United States)

Ferrando, Pere J.; Pallero, Rafael; Anguiano-Carrasco, Cristina

2013-01-01

The present study has two main interests. First, some pending issues about the psychometric properties of the CTAC (an anxiety questionnaire for blind and visually-impaired people) are assessed using item response theory (IRT). Second, the linear model is compared to the graded response model (GRM) in terms of measurement precision, sensitivity…

Neutron polarizing set-up of the Sofia IRT research reactor

International Nuclear Information System (INIS)

Krezhov, K.; Mikhajlova, V.; Okorokov, A.

1990-01-01

Neutron polarizing set-up of one of the horizontal beam tubes of the IRT-200 research reactor of the Bulgarian Institute of Nuclear Research and Nuclear Energy is presented. Neutron mirrors are extensively used in an effort to compensate the moderate reactor beam intensity by the high reflected intensity and wide-band transmittance of the mirror neutron guides. Time-to-flight technique using a slotted neutron absorbing chopper with a horizontal rotation axis has been applied to obtain the exit neutron spectra. Beam polarization and flipping ratios have been determined. Cadmium ratio in the polarized beam has been found almost 10 4 and the average polarization has been measured to be higher than 96%. 3 figs, 3 refs

Design and Preliminary Results of a Feedback Circuit for Plasma Displacement Control in IR-T1 Tokamak

International Nuclear Information System (INIS)

TalebiTaher, A.; Ghoranneviss, M.; Tarkeshian, R.; Salem, M. K.; Khorshid, P.

2008-01-01

Since displacement is very important for plasma position control, in IR-T1 tokamak a combination of two cosine coils and two saddle sine coils is used for horizontal displacement measurement. According to the multiple moment theory, the output of these coils linearly depends to radial displacement of plasma column. A new circuit for adding these signals to feedback system designed and unwanted effects of other fields in final output compensated. After compensation and calibration of the system, the output of horizontal displacement circuits applied to feedback control system. By considers the required auxiliary vertical field, a proportional amplifier and driver circuit are constructed to drive power transistors these power transistors switch the feedback bank capacitors. In the experiment, a good linear proportionality between displacement and output observed by applying an appropriate feedback field, the linger confinement time in IR-T1 tokamak obtained, applying this system to discharge increased the plasma duration and realizes repetitive discharges

Technology and Teaching: Promoting Active Learning Using Individual Response Technology in Large Introductory Psychology Classes

Science.gov (United States)

Poirier, Christopher R.; Feldman, Robert S.

2007-01-01

Individual response technology (IRT), in which students use wireless handsets to communicate real-time responses, permits the recording and display of aggregated student responses during class. In comparison to a traditional class that did not employ IRT, students using IRT performed better on exams and held positive attitudes toward the…

Li-Yorke chaos in linear dynamics

Czech Academy of Sciences Publication Activity Database

Bernardes Jr., N.C.; Bonilla, A.; Müller, Vladimír; Peris, A.

2015-01-01

Roč. 35, č. 6 (2015), s. 1723-1745 ISSN 0143-3857 R&D Projects: GA ČR GA201/09/0473; GA AV ČR IAA100190903 Institutional support: RVO:67985840 Keywords : Li-York chaos * Banach space * Fréchet space Subject RIV: BA - General Mathematics Impact factor: 0.983, year: 2015 http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=9884748&fileId=S0143385714000200

Annual report of the working group 'fuel pin and fuel element mechanics' of the Institut fuer Reaktortechnik (IRT) of the Technische Hochschule Darmstadt for the Fast Breeder Project

International Nuclear Information System (INIS)

Fabian, H.; Humbach, W.; Lassmann, K.; Mueller, J.J.; Preusser, T.; Schmelz, K.

1978-09-01

This report comprises six single lectures given at an information meeting organized by the Institut fuer Reaktortechnik der Technischen Hochschule Darmstadt (IRT) in Darmstadt on April 24, 1978. The lectures are an account of work performed at IRT on the mechanics of fuel pins and fuel elements and supported by the Fast Breeder Project (PSB) of KfK. These activities can be broken down into studies of the integral fuel pin (URANUS computer code) and into multidimensional studies of the fuel pin using the finite-element method (FINEL and ZIDRIG computer codes). Moreover, a report is presented of the status of the test facility for simulation of out-of-pile cladding tube loads and of the IRT project on the simulation and analysis of radiation damage. (orig./GL) [de

Karma Testlerin Eşitlenmesinde MTK Eşitleme Yöntemlerinin Eşitlik Özelliği Korunumu Ölçütüne Göre Karşılaştırılması

Directory of Open Access Journals (Sweden)

Neşe ÖZTÜRK GÜBEŞ

2015-06-01

Full Text Available In this study, Item Response Theory (IRT true-score equating and observed-score equating methods were compared based on preserving test equity property. The data used in this study were 8th grade mathematics test item responses which obtained from booklet 5 and 6 of Trends in International Mathematics and Science Study (TIMSS 2011 Turkey sample. Results showed that while IRT true-score equating outperformed IRT observed-score equating in terms preserving first-order equity, however IRT observed-score equating method IRT true- score equating in terms of second order equity property

Quantifying Soil Carbon Change from Wildfires in Peatland Ecosystems of the Eastern United States Using Repeat LiDAR

Science.gov (United States)

Reddy, A.; Hawbaker, T. J.; Zhu, Z.; Ward, S.; Wurster, F.; Newcomb, D.

2013-12-01

Wildfires are an increasing concern in peatland ecosystems along the coastal plains of the Eastern US. Human- and climate-induced changes to the ecosystems' hydrology can leave the soils, heavy with organic matter, susceptible to combustion in wildfires. This results in large losses of carbon that took many years to accumulate. However, accurately quantifying carbon losses in peatlands from wildfires is challenging because field data collection over extensive areas is difficult. For this study, our first objective was to evaluate the use of pre- and post-fire LiDAR data to quantify changes in surface elevations and soil carbon stocks for the 2011 Lateral West fire, which occurred in the Great Dismal Swamp National Wildlife Refuge (GDSNWR), Virginia, USA. Our second objective was to use a Monte Carlo approach to estimate how the vertical error in LiDAR points affected our calculation of soil carbon emissions. Bare-earth LiDAR points from 2010 and 2012 were obtained for GDSNWR with densities of 2 pulses/m2 and vertical elevation RMSE of 9 and 7 cm, respectively. Monte Carlo replicates were used to perturb individual bare-earth LiDAR points and generate probability distributions of elevation change within 10 m grid cells. Change in soil carbon were calculated within the Monte Carlo replicates by multiplying the LiDAR-derived volume of soil loss by depth-specific published values of soil bulk density, organic matter content, and carbon content. The 5th, 50th and 95th percentiles of the elevation and carbon change distributions were outputted as raster layers. Loss in soil volume ranged from 10,820,000 to 13,190,000 m3 based on vertical error. Carbon loss within the entire area burned by the Lateral West fire perimeter (32.1 km2), based on the 5th, 50th and 95th percentiles was 0.64, 0.96, and 1.33 Tg C, respectively. Our study demonstrated a method to use LiDAR data to quantify carbon loss following fires in peatland ecosystems and incorporate elevation errors to

Thèses de doctorat soutenues en 2010

Directory of Open Access Journals (Sweden)

2011-03-01

Full Text Available Juan Redmond, Logique Dynamique de la Fiction. Pour une Approche DialogiqueThèse soutenue le 3 juillet 2010 à l’Université de Lille 3.Composition du juryNorah dei Cas, Université de Lille 3Jacques Dubucs, Université de Paris-IGerhard Heinzmann, Université de NancyPaul Gochet, Université de de LiègeJohn Woods, University of British ColumbiaShahid Rahman, Université de Lille 3, directeur de thèse.RésuméCette thèse porte sur l’élaboration d’une structure argumentative dynamique dans le cadre con...

Management and inspection of integrity of spent fuel from IRT MEPhI research reactor

International Nuclear Information System (INIS)

Aden, V.G.; Bulkin, S.Y.; Sokolov, A.V.; Bushuev, A.V.; Redkin, A.F.; Portnov, A.A.

2002-01-01

The information on wet storage and dry storage of the spent nuclear fuel (SNF) of the IRT MEPhI reactor and experience from SNF shipment for reprocessing are presented. The procedure and a facility for nondestructive inspection of local power density fields and the burnup of fuel assemblies based on studying the γ-activity of some fission products generated in U 235 and procedure for inspection of the fuel element cladding leak tightness are described. (author)

ITER on display at Yokohama, Japan

International Nuclear Information System (INIS)

Green, B.

1998-01-01

During the 17th IAEA Fusion Energy Conference, held in Yokohama, Japan, from 19-24 October 1998, the ITER Project exhibited a display, primarily of the research and development which has taken place to support the design of ITER

Electronic Properties of LiFePO4 and Li doped LiFePO4

International Nuclear Information System (INIS)

Zhuang, G.V.; Allen, J.L.; Ross, P.N.; Guo, J.-H.; Jow, T.R.

2005-01-01

The potential use of different iron phosphates as cathode materials in lithium-ion batteries has recently been investigated.1 One of the promising candidates is LiFePO4. This compound has several advantages in comparison to the state-of-the-art cathode material in commercial rechargeable lithium batteries. Firstly, it has a high theoretical capacity (170 mAh/g). Secondly, it occurs as mineral triphylite in nature and is inexpensive, thermally stable, non-toxic and non-hygroscopic. However, its low electronic conductivity (∼10-9 S/cm) results in low power capability. There has been intense worldwide research activity to find methods to increase the electronic conductivity of LiFePO4, including supervalent ion doping,2 introducing non-carbonaceous network conduction3 and carbon coating, and the optimization of the carbon coating on LiFePO4 particle surfaces.4 Recently, the Li doped LiFePO4 (Li1+xFe1-xPO4) synthesized at ARL has yield electronic conductivity increase up to 106.5 We studied electronic structure of LiFePO4 and Li doped LiFePO4 by synchrotron based soft X-ray emission (XES) and X-ray absorption (XAS) spectroscopies. XAS probes the unoccupied partial density of states, while XES the occupied partial density of states. By combining XAS and XES measurements, we obtained information on band gap and orbital character of both LiFePO4 and Li doped LiFePO4. The occupied and unoccupied oxygen partial density of states (DOS) of LiFePO4 and 5 percent Li doped LiFePO4 are presented in Fig. 1. Our experimental results clearly indicate that LiFePO4 has wideband gap (∼ 4 eV). This value is much larger than what is predicted by DFT calculation. For 5 percent Li doped LiFePO4, a new doping state was created closer to the Fermi level, imparting p-type conductivity, consistent with thermopower measurement. Such observation substantiates the suggestion that high electronic conductivity in Li1.05Fe0.95 PO4 is due to available number of charge carriers in the material

A Review of the Effects on IRT Item Parameter Estimates with a Focus on Misbehaving Common Items in Test Equating.

Science.gov (United States)

Michaelides, Michalis P

2010-01-01

Many studies have investigated the topic of change or drift in item parameter estimates in the context of item response theory (IRT). Content effects, such as instructional variation and curricular emphasis, as well as context effects, such as the wording, position, or exposure of an item have been found to impact item parameter estimates. The issue becomes more critical when items with estimates exhibiting differential behavior across test administrations are used as common for deriving equating transformations. This paper reviews the types of effects on IRT item parameter estimates and focuses on the impact of misbehaving or aberrant common items on equating transformations. Implications relating to test validity and the judgmental nature of the decision to keep or discard aberrant common items are discussed, with recommendations for future research into more informed and formal ways of dealing with misbehaving common items.

Corrosion of type 316 stainless steel in molten LiF-LiCl-LiBr

International Nuclear Information System (INIS)

Tortorelli, P.F.; DeVan, J.H.; Keiser, J.R.

1981-01-01

The properties of LiF-LiCl-LiBr salt make it attractive as a solvent for extracting tritium from a fusion reactor lithium blanket. Consequently, the corrosion of type 316 stainless steel by flowing (about 15 mm/s) LiF-LiCl-LiBr at a maximum temperature of 535 0 C was studied to determine whether compatibility with the structural material would be limiting in such a system. The corrosion rate was found to be low ( 0 C (approximately that of type 316 stainless steel exposed to lithium flowing at a similar velocity). At the proposed operating temperature (less than or equal to approx. 535 0 C), however, it appears that type 316 stainless steel has acceptable compatibility with the tritium-processing salt LiF-LiCl-LiBr for use with a lithium blanket

Nanoconfined LiBH4 as a Fast Lithium Ion Conductor

DEFF Research Database (Denmark)

Blanchard, Didier; Nale, Angeloclaudio; Sveinbjörnsson, Dadi Þorsteinn

2015-01-01

is associated with a fraction of the confined borohydride that shows no phase transition, and most likely located close to the interface with the SiO2 pore walls. These results point to a new strategy to design low-temperature ion conducting solids for application in all solid-state lithium ion batteries, which......Designing new functional materials is crucial for the development of efficient energy storage and conversion devices such as all solid-state batteries. LiBH 4 is a promising solid electrolyte for Li-ion batteries. It displays high lithium mobility, although only above 110 °C at which a transition...

A Comparison between Linear IRT Observed-Score Equating and Levine Observed-Score Equating under the Generalized Kernel Equating Framework

Science.gov (United States)

Chen, Haiwen

2012-01-01

In this article, linear item response theory (IRT) observed-score equating is compared under a generalized kernel equating framework with Levine observed-score equating for nonequivalent groups with anchor test design. Interestingly, these two equating methods are closely related despite being based on different methodologies. Specifically, when…

Hydrogen retention in Li and Li-C-O films

Science.gov (United States)

Buzi, Luxherta; Nelson, Andrew O.; Yang, Yuxin; Kaita, Robert; Koel, Bruce E.

2017-10-01

The efficiency of Li in binding H isotopes has led to reduced recycling in magnetic fusion devices and improved plasma performance. Since elemental Li surfaces are challenging to maintain in fusion devices due to the presence of impurities, parameterizing and understanding the mechanisms for H retention in various Li compounds (Li-C-O), in addition to pure Li, is crucial for Li plasma-facing material applications. To determine H retention in Li and Li-C-O films, measurements were done under ultrahigh vacuum conditions using temperature programmed desorption (TPD). Thin Li films (20 monolayers) were deposited on a nickel single crystal substrate and irradiated with 500 eV H2+ions at surface temperatures from 90K to 520K. Initial measurements on Li and Li-O films showed that the retention was comparable and dropped exponentially with surface temperature, from 95% at 90 K to 35% at 520 K. Auger electron spectroscopy and TPD showed that H was retained as lithium hydride (LiH) in pure Li and as lithium hydroxide (LiOH) in Li2O, which decomposed to H2O and Li2O at temperatures higher than 470K. H retention in Li-C and Li-C-O films will be determined over a similar temperature range, and the sputtering rate of these layers with H ions will also be reported. This material is based upon work supported by the U.S. Department of Energy, Office of Science/Fusion Energy Sciences under Award Number DE-SC0012890.

Kinetic Model of LiFePO4 Formation Using Non-Isothermal Thermogravimetric Analysis

Directory of Open Access Journals (Sweden)

Abdul Halim

2014-03-01

Full Text Available The formation reaction of LiFePO4 from decomposition of precursors LiOH, FeSO4.7H2O and (NH42HPO4 with mol ratio of Li:Fe:P=1:1:1 was investigated. The experiment was carried out by thermogravimetric differential thermal analysis (TG-DTA method using nitrogen as atmosfer at a constant heating rate to obtain kinetic constant parameters. Several heating rates were selected, there are 5, 7, 10, 15, 17.5, 22.5 and 25 °C/min. Activation energy, pre-exponential factor and reaction order were taken using Kissinger method and obtained respectively 56.086 kJ/mol, 6.95×108 min-1, and 1.058. Based on fitting result between reaction model and experiment were obtained that reaction obeyed the three dimension diffusion model. © 2014 BCREC UNDIP. All rights reservedReceived: 19th September 2013; Revised: 9th December 2013; Accepted: 23rd January 2014 [How to Cite: Halim, A., Widiyastuti, W., Setyawan, H., Winardi, S. (2014. Kinetic of LiFePO4 For-mation Using Non-isothermal Thermogravimetric Analysis. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (1: 60-65. (doi:10.9767/bcrec.9.1.5508.60-65][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.1.5508.60-65] 

Possible use of dual purpose dry storage casks for transportation and future storage of spent nuclear fuel from IRT-Sofia

International Nuclear Information System (INIS)

Manev, L.; Baltiyski, M.

2003-01-01

Objectives: The main objective of the present paper is related to one of the priority goals stipulated in Bulgarian Governmental Decision No.332 from May 17, 1999 - removal of SNF from IRT-Sofia site and its exporting for reprocessing and/or for temporary storage at Kozloduy NPP site. The variant of using dual purpose dry storage casks for transportation and future temporary storage of SNF from IRT-Sofia aims to find out a reasonable alternative of the existing till now variant for temporary SNF storage under water in the existing Kozloduy NPP Spent Fuel Storage Facility until its export for reprocessing. Results: Based on the given data for the condition of 73 Spent Nuclear Fuel Assemblies (SNFA) stored in the storage pool and technical data as well as data for available equipment and IRT-Sofia layout the following framework are specified: draft technical features of dual purpose dry storage casks and their overall dimensions; the suitability of the available equipment for safety and reliable performance of transportation and handling operations of assemblies from storage pool to dual purpose dry storage casks; the necessity of new equipment for performance of the above mentioned operations; Assemblies' transportation and handling operations are described; requirements to and conditions for future safety and reliable storage of SNFA loaded casks are determined. When selecting the technical solutions for safety assurance during performance of site handling operations of IRT-Sofia and for description of the exemplary casks the Effective Bulgarian Regulations are considered. The experience of other countries in performance of transfer and transportation of SNFA from such types of research reactors is taken into account. Also, Kozloduy NPP experience in SNF handling operations is taken into account. Conclusions: The Decision of Council of Minister for refurbishment of research reactor into a low power one and its future utilization for experimental and training

Chemically grafted carbon-coated LiFePO4 using diazonium chemistry

Science.gov (United States)

Delaporte, Nicolas; Perea, Alexis; Amin, Ruhul; Zaghib, Karim; Bélanger, Daniel

2015-04-01

The effect of surface functionalization of aminophenyl and bromophenyl groups on carbon-coated LiFePO4 and the electrochemical properties of composite electrode containing these materials are reported. The functionalization was performed by spontaneous reduction of the corresponding in situ generated diazonium ions. The resulting chemically grafted LiFePO4/C materials were characterized by energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) to confirm the presence of the surface organic species. XRD analyses indicated the cathode material was partially oxidized. Thermogravimetric and elemental analyses revealed the loading of grafted molecules was between 0.2 and 1.1 wt.% depending on the reaction conditions. Interestingly, the electrochemical performances of the modified LiFePO4/C are not adversely affected by the presence of either aminophenyl and bromophenyl groups at the carbon surface, and in fact the grafted LiFePO4/C displayed slightly superior discharge capacity at the highest C rate investigated for a low loading of organic molecules.

Comparing Different Approaches of Bias Correction for Ability Estimation in IRT Models. Research Report. ETS RR-08-13

Science.gov (United States)

Lee, Yi-Hsuan; Zhang, Jinming

2008-01-01

The method of maximum-likelihood is typically applied to item response theory (IRT) models when the ability parameter is estimated while conditioning on the true item parameters. In practice, the item parameters are unknown and need to be estimated first from a calibration sample. Lewis (1985) and Zhang and Lu (2007) proposed the expected response…

Radiation conditions at the training IRT-2000 and IR-100 reactors

International Nuclear Information System (INIS)

Fedorin, Eh.V.; Bronshtejn, I.Eh; Martynov, Yu.N.; Chistyakov, N.I.

1978-01-01

The experience is reviewed of radiation hygiene surveys and radiation safety provision during instructional processes on two training and research nuclear reactors of the IRT-2000 type (No. 1 and No. 2) and on an IR-200 reactor. From an analysis of individual dosimetry data the conclusion is made that the trainees and personnel are exposed mainly to external gamma-radiation and also, to a minor degree, to thermal neutrons and beta-radiation. It has been found that a high level of radiation safety is ensured on the training and research so that research and instruction activities are conducted at annual levels of exposure substantially lower than 0.5 rem in the case of trainees and 5 rem in the case of personnel

Hyperenhanced Li - Li Chemonuclear Fusion

International Nuclear Information System (INIS)

Ikegami, Hidetsugu

2006-01-01

A new fusion scheme, the Li - Li chemonuclear fusion is presented, where nuclear fusion reactions are linked to atomic fusion reactions. Lithium ions are implanted on a surface of metallic Li liquid at an energy of nuclear stopping (several keV/amu). The ions collide slowly with liquid Li atoms without electronic excitation and lead to the Li - Li chemonuclear fusion through the formation of united atoms or quasi-C atoms at their turning points. Inside the quasi-atoms twin nuclei are confined within respective sub-pm scale spheres of zero-point oscillation and form themselves into ultradense intermediate nuclear complexes. Their density is million times as large as the solar interior density and close to densities of white dwarfs or white-dwarf progenitors of supernovae. This confinement of nuclear complexes is enormously prolonged towards the pycno-nuclear reactions induced by the zero-point oscillation under the presence of thermodynamic force specified by the Gibbs energy change in the quasi-atom formation in the liquid. Resulted rate enhancement of nuclear fusion by a factor of 10 48 has been anticipated. The enhancement is also argued in connection with the Bose-Einstein condensation

Enhanced electrochemical performance of LiMnPO4 by Li+-conductive Li3VO4 surface coatings

International Nuclear Information System (INIS)

Dong, Youzhong; Zhao, Yanming; Duan, He; Liang, Zhiyong

2014-01-01

By a simple wet ball-milling method, Li 3 VO 4 -coated LiMnPO 4 samples were prepared successfully for the first time. The thin Li 3 VO 4 coating layer with a three-dimensional Li + -ion transport path and high mobility of Li + -ion strongly adhered to the LiMnPO 4 material reduces Mn dissolution and increases the Li + flux through the surface of the LiMnPO 4 itself by preventing formation of phases on the surface that would normally block Li + as well as Li + -ion permeation into the surface of the LiMnPO 4 electrode and therefore improve the rate capability as well as the cycling stability of LiMnPO 4 materials. The electrochemical testing shows that the 5% Li 3 VO 4 -coated LiMnPO 4 sample shows a clear voltage plateau in the charge curves and a much higher reversible capacity at different discharge rates compared with the pristine LiMnPO 4 . EIS results also show that the surface charge transfer resistance and Warburg impedance of the Li 3 VO 4 -coated LiMnPO 4 samples significantly decreased. The surface charge transfer resistance and Warburg impedance for the pristine LiMnPO 4 are 955.1 Ω and 400.3 Ω, respectively. While, for the 5% Li 3 VO 4 -coated LiMnPO 4 , the value are only 400.2 Ω and 283.6 Ω, respectively. The surface charge transfer resistance decreases more than half. All of the improved performance will be favorable for application of the LiMnPO 4 in high-power lithium ion batteries

The effect of Li2O and LiF on structural properties of cobalt doped borate glasses

Directory of Open Access Journals (Sweden)

A.M. Abdelghany

2017-10-01

Full Text Available Two glassy (LiF–B2O3 and (Li2O–B2O3 systems containing different content of CoO dopants (0.05, 0.1, 0.15, 0.2 wt% were prepared. UV/Vis optical absorption of base glasses reveals a strong UV absorption bands attributed to unavoidable contaminated trace iron impurities. CoO-doped glasses show extra three visible bands due to both octahedral and tetrahedral Co2+ ions related to the little variation between energies of ligand field stabilization between the two coordination states. Fluoride containing glasses show limited variations in the spectral properties due to the different ligand strength of the anions (F− and O2−. FTIR spectra display characteristic modes of vibrations due to triangular and tetrahedral borate groups. It is assumed that LiF acts as Li2O in promoting the formation of tetrahedral (BO3F units which possess the same wavenumber position for vibrations of (BO4 units in the range of 800–1200 cm−1. CoO causes no distinct variations in number or position of characteristic IR vibrational bands due to their low dopant level (0.05–0.2%. A new suggested trial has been utilized to calculate the percent of four coordinated borons from both optical and FTIR spectra to give more insight on the role of CoO as dopant on these spectral properties and on the calculated parameters.

Hybrid microwave synthesis and characterization of the compounds in the Li-Ti-O system

Energy Technology Data Exchange (ETDEWEB)

Yang, Li Hong; Dong, Cheng; Guo, Juan [National Laboratory for Superconductivity, Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Science, P.O. Box 603, Beijing 100080 (China)

2008-01-03

Hybrid microwave synthesis has been applied for preparation of Li{sub 4}Ti{sub 5}O{sub 12}, Li{sub 2}Ti{sub 3}O{sub 7}, Li{sub 2}TiO{sub 3} and LiTiO{sub 2} for the first time. Stepwise heating was used for avoiding the instantaneous release of gas by-product and obtaining well-shaped samples. The samples were characterized by powder X-ray diffraction, energy-dispersive X-ray analysis and scanning electron microscopy. The obtained samples have relatively uniform particle sizes. The electrochemical performance of Li{sub 4}Ti{sub 5}O{sub 12} and Li{sub 2}Ti{sub 3}O{sub 7} were investigated. The first discharge capacity of Li{sub 4}Ti{sub 5}O{sub 12} was 150 mAh g{sup -1} and 141 mAh g{sup -1} after 27 cycles and a very flat discharge and charge curve of Li{sub 4}Ti{sub 5}O{sub 12} was shown at about 1.56 V. Similarly, Li{sub 2}Ti{sub 3}O{sub 7} exhibits good cycle performance. The initial discharge capacity is 118 mAh g{sup -1} and 30th cycle is still 112 mAh g{sup -1}. (author)

Flexible Li-CO{sub 2} batteries with liquid-free electrolyte

Energy Technology Data Exchange (ETDEWEB)

Hu, Xiaofei; Li, Zifan; Chen, Jun [Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) and State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin (China)

2017-05-15

Developing flexible Li-CO{sub 2} batteries is a promising approach to reuse CO{sub 2} and simultaneously supply energy to wearable electronics. However, all reported Li-CO{sub 2} batteries use liquid electrolyte and lack robust electrolyte/electrodes structure, not providing the safety and flexibility required. Herein we demonstrate flexible liquid-free Li-CO{sub 2} batteries based on poly(methacrylate)/poly(ethylene glycol)-LiClO{sub 4}-3 wt %SiO{sub 2} composite polymer electrolyte (CPE) and multiwall carbon nanotubes (CNTs) cathodes. The CPE (7.14 x 10{sup -2} mS cm{sup -1}) incorporates with porous CNTs cathodes, displaying stable structure and small interface resistance. The batteries run for 100 cycles with controlled capacity of 1000 mAh g{sup -1}. Moreover, pouch-type flexible batteries exhibit large reversible capacity of 993.3 mAh, high energy density of 521 Wh kg{sup -1}, and long operation time of 220 h at different degrees of bending (0-360 ) at 55 C. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Salts purification and redox potential measurement for the molten LiF-ThF4-UF4 mixture

International Nuclear Information System (INIS)

Afonichkin, V.; Bovet, A.; Shishkin, V.

2010-01-01

The 'dry' techniques of producing and clearing of some metals fluorides, their mixtures and cakes of a given composition obtained without usage gaseous HF for experiments under the Project ISTC No. 3749 are developed. The products of synthesizing and purification of oxygen-containing compounds, are studied by methods X-ray diffraction analysis, gravimetry or IR spectrometry. The experimental studies confirmed that solid NH 4 HF 2 can be efficiently used instead of an unsafe and corrosive HF gas for removal of oxygen-containing impurities from metal fluorides and for conversion of uranium and thorium dioxides to anhydrous tetra-fluorides. These processes do not require expensive equipment and special measures of safety. The electrochemical behavior of UF 4 solutions in a melt 77 LiF-23ThF 4 (mole%) was studied by cyclic voltammetry. Formal analysis of the obtained dependencies showed that in our experimental conditions the recharge U(IV) to U(III) is qualitatively consistent with voltammetric criteria and can be classified as reversible. However, the results of mathematical processing of voltammograms show that the basic calculated characteristics of this reaction differ from the theoretical values corresponding one-electron process controlled by the diffusion rate. This indicates quasi-reversibility of the studied reaction. (authors)

Ternary nitrides for hydrogen storage: Li-B-N, Li-Al-N and Li-Ga-N systems

International Nuclear Information System (INIS)

Langmi, Henrietta W.; McGrady, G. Sean

2008-01-01

This paper reports an investigation of hydrogen storage performance of ternary nitrides based on lithium and the Group 13 elements boron, aluminum and gallium. These were prepared by ball milling Li 3 N together with the appropriate Group 13 nitride-BN, AlN or GaN. Powder X-ray diffraction of the products revealed that the ternary nitrides obtained are not the known Li 3 BN 2 , Li 3 AlN 2 and Li 3 GaN 2 phases. At 260 deg. C and 30 bar hydrogen pressure, the Li-Al-N ternary system initially absorbed 3.7 wt.% hydrogen, although this is not fully reversible. We observed, for the first time, hydrogen uptake by a pristine ternary nitride of Li and Al synthesized from the binary nitrides of the metals. While the Li-Ga-N ternary system also stored a significant amount of hydrogen, the storage capacity for the Li-B-N system was near zero. The hydrogenation reaction is believed to be similar to that of Li 3 N, and the enthalpies of hydrogen absorption for Li-Al-N and Li-Ga-N provide evidence that AlN and GaN, as well as the ball milling process, play a significant role in altering the thermodynamics of Li 3 N

Lithium ionic mobility study in xLi{sub 2}CO{sub 3}-yLiI (x = 95-70, y = 5-30 wt.%) solid electrolyte by impedance spectroscopy technique

Energy Technology Data Exchange (ETDEWEB)

Omar, Mohd Khari; Ahmad, Azizah Hanom [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor D.E. (Malaysia); Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor D.E. (Malaysia)

2015-08-28

A detailed systematic study on the effects of different amount (wt.%) of LiI addition on the electrical conductivity and dielectric behavior of the xLi{sub 2}CO{sub 3}-xLiI (x = 95-70, y = 5-30 wt.%) electrolyte system was carried out. The samples with different compositions were prepared and ground by mechanical milling method. The electrical and dielectric properties of the samples over a range of frequency (50Hz – 1MHz) were investigated by deploying electrical impedance spectroscopy (EIS) technique in a series of temperature set (298–373K). Normally, Li{sub 2}CO{sub 3} itself shows a very low electrical conductivity (10{sup −5} Scm{sup −1}). However, the electrical conductivity of the system was found to be increased (10{sup −3} Scm{sup −1}) as the lithium salt (LiI) were introduced to the system. The dielectric analysis displayed that the activation energy was inversely proportional to the increment of LiI (wt.%). As the electrical conductivity reached their maximum value (4.63 × 10{sup −3} Scm{sup −1}) at the 20 wt.% of LiI, the activation energy was dropped to the minimum (0.1 eV). The electrical conductivity increases with the temperature (298 – 373K) indicate that the system obeys Arrhenius law.

Homeopathic medicines cause Th1 predominance and induce spleen and megakaryocytes changes in BALB/c mice infected with Leishmania infantum.

Science.gov (United States)

Cajueiro, Ana Paula Bacellar; Goma, Ester Puna; Dos Santos, Hilton Antônio Mata; Almeida Rodrigues, Igor; Toma, Helena Keiko; Araújo, Silvana Marques; Bonamin, Leoni Villano; Gomes, Nelson Brêtas de Noronha; Castelo-Branco, Morgana Teixeira Lima; de Souza Dias, Edilma Paraguai; Dos Santos Pyrrho, Alexandre; Holandino, Carla

2017-07-01

The prevalence of Th1/Th2 response, spleen changes and megakaryocytes were investigated in BALB/c mice (n=138) infected with Leishmania infantum, and treated with Leishmania infantum 30× (10 -30 ) biotherapy - BioLi30×. We performed controlled experiments using 8-to-12-week-old mice, infected with 5×10 7 L. infantum promastigotes, divided into eight groups: G1 (healthy), G2 (infected with L. infantum), G3 (BioLi30× pre-treated), G4 (BioLi30× pre/post-treated), G5 (BioLi30× post-treated), G6 (Water 30× post-treated), G7 (Antimonium crudum 30× post-treated) and G8 (Glucantime® post-treated). G3-G7 groups were orally treated with their respective drugs diluted in filtered water (1:10), and G8 received Glucantime® (0.6mg/100µl of PBS), intraperitoneally. Spleen fragments were submitted to double blind histopathological evaluation and the number of megakaryocytes was counted. Besides, animals' serum was measured after 49days of infection, and cytokines (IFN-γ, IL-4, IL-10, IL-12), as well as the Th1/Th2 correlation (IFN-γ/IL-4 and IFN-γ/IL-10), were analyzed. Spleen histological parameters were classified as: healthy appearance (G1); discreet (G3-G7), moderate (G2) and moderate to severe (G8) white pulp hyperplasia; proliferation of megakaryocytes (G2-G8), and intense disruption (G2-G8). All groups, except for G7, showed higher percentages of megakaryocytes per field ranging from 87% to 15%, when compared to healthy animals (G1). Th1 predominance in IFN-γ/IL-4 ratio (comparing to G2) was detected in G4, G5, G6 and G7. Finally, pre/post (BioLi30x) and post-treatment (Antimonium crudum 30x) presented reduction of megakaryocytes/spleen changes due to immunomodulation animal process, controlling the infection process, probably by the Th1 cytokine predominance. Copyright © 2017 Elsevier Ltd. All rights reserved.

Direct regeneration of recycled cathode material mixture from scrapped LiFePO4 batteries

Science.gov (United States)

Li, Xuelei; Zhang, Jin; Song, Dawei; Song, Jishun; Zhang, Lianqi

2017-03-01

A new green recycling process (named as direct regeneration process) of cathode material mixture from scrapped LiFePO4 batteries is designed for the first time. Through this direct regeneration process, high purity cathode material mixture (LiFePO4 + acetylene black), anode material mixture (graphite + acetylene black) and other by-products (shell, Al foil, Cu foil and electrolyte solvent, etc.) are recycled from scrapped LiFePO4 batteries with high yield. Subsequently, recycled cathode material mixture without acid leaching is further directly regenerated with Li2CO3. Direct regeneration procedure of recycled cathode material mixture from 600 to 800 °C is investigated in detail. Cathode material mixture regenerated at 650 °C display excellent physical, chemical and electrochemical performances, which meet the reuse requirement for middle-end Li-ion batteries. The results indicate the green direct regeneration process with low-cost and high added-value is feasible.

A Conceptual Framework for Ambient Learning Displays

NARCIS (Netherlands)

Börner, Dirk; Kalz, Marco; Specht, Marcus

2011-01-01

Börner, D., Kalz, M., & Specht, M. (2010, 29 November-3 December). A Conceptual Framework for Ambient Learning Displays. Poster presented at the Work-in-Progress Poster and Invited Young Researcher Symposium of the 18th International Conference on Computers in Education, Putrajaya, Malaysia:

Investigating sorption on iron-oxyhydroxide soil minerals by solid-state NMR spectroscopy: a 6Li MAS NMR study of adsorption and absorption on goethite

DEFF Research Database (Denmark)

Nielsen, Ulla Gro; Paik, Younkee; Julmis, Keinia

2005-01-01

High-resolution 2H MAS NMR spectra can be obtained for nanocrystalline particles of goethite (alpha-FeOOH, particle size approximately 4-10 nm) at room temperature, facilitating NMR studies of sorption under environmentally relevant conditions. Li sorption was investigated as a function of pH, th...... on the goethite surface. Even larger Li hyperfine shifts (289 ppm) were observed for Li+-exchanged goethite, which contains lithium ions in the tunnels of the goethite structure, confirming the Li assignment of the 145 ppm Li resonance to the surface sites. Udgivelsesdato: 2005-Oct-6...

Enhanced electrochemical performance and thermal stability of LiNi0.80Co0.15Al0.05O2 via nano-sized LiMnPO4 coating

International Nuclear Information System (INIS)

Duan, Jianguo; Wu, Ceng; Cao, Yanbing; Du, Ke; Peng, Zhongdong; Hu, Guorong

2016-01-01

Highlights: • LiMnPO 4 was introduced to modify Ni-rich cathode materials. • LiMnPO 4 uniformly coated NCA composite has been constructed successfully. • Olivine structured skin restrains the formation of residues on NCA during cycling. • LiMnPO 4 improves the structural and thermal stability of NCA@LMP. - Abtract: LiNi 0.80 Co 0.15 Al 0.05 O 2 has been widely pursued as an alternative to LiCoO 2 cathode materials for lithium ion batteries because of its high capacity and acceptable cycling property. However, that NCA can react with commercialized electrolyte during cycling restrains its wide use. Here, olivine structured LiMnPO 4 has been introduced to modify the surface of NCA by a sol-gel method. Characterizations from structure, morphology and composition analysis technologies demonstrate that a LiMnPO 4 layer has been uniformly coated on NCA particles. The electrochemical performance and thermo stability of modified samples are characterized by electrochemical tests, XRD and metallic nail penetration tests. The olivine structured skin, which provides structural and thermal stability, is used to encapsulate the high powered core via using the effective coating technique. The modified material displays a high discharge capacity of 211.0 mAh g −1 at 0.2 C and better rate performance and promoted cycling stability than the uncoated control sample. Furthermore, the thermal stability of coated sample in the delithiated state is upgraded to the pristine powders remarkably.

Item Response Theory with Covariates (IRT-C): Assessing Item Recovery and Differential Item Functioning for the Three-Parameter Logistic Model

Science.gov (United States)

Tay, Louis; Huang, Qiming; Vermunt, Jeroen K.

2016-01-01

In large-scale testing, the use of multigroup approaches is limited for assessing differential item functioning (DIF) across multiple variables as DIF is examined for each variable separately. In contrast, the item response theory with covariate (IRT-C) procedure can be used to examine DIF across multiple variables (covariates) simultaneously. To…

Potential application of thermography (IRT in animal production and for animal welfare. A case report of working dogs

Directory of Open Access Journals (Sweden)

Veronica Redaelli

2014-06-01

Full Text Available INTRODUCTION. The authors describe the thermography technique in animal production and in veterinary medicine applications. The thermographic technique lends itself to countless applications in biology, thanks to its characteristics of versatility, lack of invasiveness and high sensitivity. Probably the major limitation to most important aspects for its application in the animal lies in the ease of use and in its extreme sensitivity. Materials and methods. This review provides an overview of the possible applications of the technique of thermo visual inspection, but it is clear that every phenomenon connected to temperature variations can be identified with this technique. Then the operator has to identify the best experimental context to obtain as much information as possible, concerning the physiopathological problems considered. Furthermore, we reported an experimental study about the thermography (IRT as a noninvasive technique to assess the state of wellbeing in working dogs. RESULTS. The first results showed the relationship between superficial temperatures and scores obtained by the animal during the behavioral test. This result suggests an interesting application of infrared thermography (IRT to measure the state of wellbeing of animals in a noninvasive way.

A Conceptual Framework for Ambient Learning Displays

NARCIS (Netherlands)

Börner, Dirk; Kalz, Marco; Specht, Marcus

2010-01-01

Börner, D., Kalz, M., & Specht, M. (2010). A Conceptual Framework for Ambient Learning Displays. In B. Chang, T. Hirashima, & H. Ogata (Eds.), Joint Proceedings of the Work-in-Progress Poster and Invited Young Researcher Symposium for the 18th International Conference on Computers in Education (pp.

First-Principles Study of Phosphorene and Graphene Heterostructure as Anode Materials for Rechargeable Li Batteries.

Science.gov (United States)

Guo, Gen-Cai; Wang, Da; Wei, Xiao-Lin; Zhang, Qi; Liu, Hao; Lau, Woon-Ming; Liu, Li-Min

2015-12-17

There is a great desire to develop the high-efficient anodes materials for Li batteries, which require not only large capacity but also high stability and mobility. In this work, the phosphorene/graphene heterostructure (P/G) was carefully explored based on first-principles calculations. The binding energy of Li on the pristine phosphorene is relatively weak (within 1.9 eV), whereas the phosphorene/graphene heterostructure (P/G) can greatly improve the binding energy (2.6 eV) without affecting the high mobility of Li within the layers. The electronic structures show that the large Li adsorption energy and fast diffusion ability of the P/G origin from the interfacial synergy effect. Interestingly, the P/G also displays ultrahigh stiffness (Cac = 350 N/m, Czz = 464 N/m), which can effectively avoid the distortion of the pristine phosphorene after the insertion of lithium. Thus, P/G can greatly enhance the cycle life of the battery. Owing to the high capacity, good conductivity, excellent Li mobility, and ultrahigh stiffness, P/G is a very promising anode material in Li-ion batteries (LIBs).

Investigation of radial propagation of electrostatic fluctuations in the IR-T1 tokamak plasma edge

Energy Technology Data Exchange (ETDEWEB)

Shariatzadeh, R; Ghoranneviss, M; Salem, M K [Plasma Physics Research Center, Science and Research Branch, Islamic Azad University (IAU), PO Box 14665-678, Tehran (Iran, Islamic Republic of); Emami, M, E-mail: rezashariatzadeh@gmail.com [Laser and Optics Research School, NSTRI, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of)

2011-01-15

The radial propagation of electrostatic fluctuation is considered extremely important for understanding cross-field anomalous transport. In this paper, two arrays of Langmuir probes are used to analyze electrostatic fluctuations in the edge of IR-T1 tokamak plasma in both the radial and the poloidal directions. The propagation characteristics of the floating potential fluctuations are analyzed by the two-point correlation technique. The wavenumber spectrum shows that there is a net radially outward propagation of turbulent fluctuations in the edge and scrape-off layer (SOL) regions. Hence, edge turbulence presumably originates from core fluctuations.

Investigation of radial propagation of electrostatic fluctuations in the IR-T1 tokamak plasma edge

International Nuclear Information System (INIS)

Shariatzadeh, R; Ghoranneviss, M; Salem, M K; Emami, M

2011-01-01

The radial propagation of electrostatic fluctuation is considered extremely important for understanding cross-field anomalous transport. In this paper, two arrays of Langmuir probes are used to analyze electrostatic fluctuations in the edge of IR-T1 tokamak plasma in both the radial and the poloidal directions. The propagation characteristics of the floating potential fluctuations are analyzed by the two-point correlation technique. The wavenumber spectrum shows that there is a net radially outward propagation of turbulent fluctuations in the edge and scrape-off layer (SOL) regions. Hence, edge turbulence presumably originates from core fluctuations.

{sup 6}LiF oleic acid capped nanoparticles entrapment in siloxanes for thermal neutron detection

Energy Technology Data Exchange (ETDEWEB)

Carturan, S., E-mail: sara.carturan@lnl.infn.it; Maggioni, G., E-mail: Gianluigi.maggioni@lnl.infn.it [Department of Physics and Astronomy, University of Padova, Via Marzolo 8, 35100 Padova (Italy); INFN, Laboratori Nazionali di Legnaro, Viale dell’Università 2, 35020 Legnaro (Italy); Marchi, T.; Gramegna, F.; Cinausero, M. [INFN, Laboratori Nazionali di Legnaro, Viale dell’Università 2, 35020 Legnaro (Italy); Quaranta, A. [Department of Industrial Engineering, University of Trento, Trento (Italy); INFN, Tifpa, Trento (Italy); Palma, M. Dalla [INFN, Laboratori Nazionali di Legnaro, Viale dell’Università 2, 35020 Legnaro (Italy); Department of Industrial Engineering, University of Trento, Trento (Italy)

2016-07-07

The good light output of siloxane based scintillators as displayed under γ-rays and α particles has been exploited here to obtain clear and reliable response toward thermal neutrons. Sensitization towards thermal neutrons has been pursued by adding {sup 6}LiF, in form of nanoparticles. Aiming at the enhancement of compatibility between the inorganic nanoparticles and the low polarity, siloxane based surrounding medium, oleic acid-capped {sup 6}LiF nanoparticles have been synthesized by thermal decomposition of Li trifluoroacetate. Thin pellets siloxane scintillator maintained their optical transmittance up to weight load of 2% of {sup 6}Li. Thin samples with increasing {sup 6}Li concentration and thicker ones with fixed {sup 6}Li amount have been prepared and tested with several sources (α, γ-rays, moderated neutrons). Light output as high as 80% of EJ212 under α irradiation was measured with thin samples, and negligible changes have been observed as a result of {sup 6}LiF addition. In case of thick samples, severe light loss has been observed, as induced by opacity. Nevertheless, thermal neutrons detection has been assessed and the data have been compared with GS20, based on Li glass, taken as a reference material.

Rheological phase synthesis of nanosized α-LiFeO_2 with higher crystallinity degree for cathode material of lithium-ion batteries

International Nuclear Information System (INIS)

Liu, Haowen; Ji, Panyin; Han, Xiaoyan

2016-01-01

In this paper, rheological phase method has been successfully applied to synthesize nanosized α-LiFeO_2, a promising cathode material of lithium-ion batteries. The formation, structure and morphology of the as-prepared powder were characterized by Thermogravimetric and differential thermal analyses (TGA/DTA), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Scanning electron microscopy (SEM). The particle size of the obtained α-LiFeO_2 ranged from 100 to 300 nm. It exhibited an initial discharge capacity 169 mAh g"−"1 at 0.1 C between 1.5 and 4.3 V, especially excellent cycling retention from the 10th to the 50th cycle (96.8%) between 1.5 and 4.3 V. The higher crystallinity degree might be responsible for the cyclability improvement. - Highlights: • α-LiFeO_2 with higher crystallinity degree has been synthesized. • The obtained samples were investigated by TGA/DTA, FTIR, SEM, XRD. • The prepared α-LiFeO_2 indicated excellent cycling retention.

Effectiveness of Item Response Theory (IRT) Proficiency Estimation Methods under Adaptive Multistage Testing. Research Report. ETS RR-15-11

Science.gov (United States)

Kim, Sooyeon; Moses, Tim; Yoo, Hanwook Henry

2015-01-01

The purpose of this inquiry was to investigate the effectiveness of item response theory (IRT) proficiency estimators in terms of estimation bias and error under multistage testing (MST). We chose a 2-stage MST design in which 1 adaptation to the examinees' ability levels takes place. It includes 4 modules (1 at Stage 1, 3 at Stage 2) and 3 paths…

Preserved dopaminergic homeostasis and dopamine-related behaviour in hemizygous TH-Cre mice

DEFF Research Database (Denmark)

Thomsen, Annika Højrup Runegaard; Jensen, Kathrine L; Fitzpatrick, Ciarán M

2017-01-01

assessment of the dopaminergic system in hemizygous tyrosine hydroxylase (TH)-Cre mice in comparison to wild-type (WT) controls. Our data show that TH-Cre mice display preserved dopaminergic homeostasis with unaltered levels of TH and dopamine as well as unaffected dopamine turnover in striatum. TH-Cre mice...

Synthesis of LiNixFe1−xPO4 solid solution as cathode materials for lithium ion batteries

International Nuclear Information System (INIS)

Qing, Rui; Yang, Ming-Che; Meng, Ying Shirley; Sigmund, Wolfgang

2013-01-01

Highlights: • Phase pure LiNi x Fe 1−x PO 4 and LiNi x Fe 1−x PO 4 /C nanocomposites were obtained via a solid state reaction method. • Crystallite sizes were around 50 nm. Linear relationship was observed between lattice parameters and chemical composition. • Synthesized materials displayed electronic conductivity similar to reported value of LiFePO 4 . Carbon coating increased the conductivity to ∼10 −3 S/cm. • Chemical delithiation via NO 2 BF 4 extracted more than 90% of lithium from the nanocomposites, proving that Ni 2+ /Ni 3+ redox couple was activated. -- Abstract: Nanosize LiNi x Fe 1−x PO 4 solid solution and LiNi x Fe 1−x PO 4 /C nanocomposites were prepared via a solid state reaction method under argon atmosphere. A single phase olivine-type structure with Pnma space group was determined by X-ray diffraction. Crystallite sizes were found to be around 50 nm. A linear relationship was observed between lattice parameters and chemical composition which follows Vegard's law. Synthesized materials displayed electronic conductivity similar to previous reported values of LiFePO 4 . Carbon coating further increased the overall conductivity of nanocomposites to the order of 10 −3 S/cm. Chemical delithiation via NO 2 BF 4 oxidant extracted more than 95% of lithium from the solid solution material accompanied by a decrease in lattice parameters

Nonlinear optical properties of Nd3+-Li+ co-doped ZnS-PVP thin films

Science.gov (United States)

Talwatkar, S. S.; Sunatkari, A. L.; Tamgadge, Y. S.; Muley, G. G.

2018-04-01

The nonlinear optical properties of Nd3+-Li+ co-doped ZnS-PVP nanocomposite were studied using a continuous wave (CW) He-Ne laser (λ = 632.8 nm)by z-scan technique. The nonlinear refractive index (n2), absorption coefficient (β) and third order nonlinear susceptibility (χ(3)) of PVP thin films embedded with Nd3+-Li+ co-doped ZnS NPs was found in the order of 10-7 cm2/W, 10-6 cm/W and 10-7 esu respectively. The nonlinearity found increasing with Nd3+-Li+ co-dopant concentration. Based on the results, it is proposed that this material is a new class of luminescent material suitable in optoelectronics devices application, especially in light-emitting devices, electroluminescent devices, display devices, etc.

Role of dopants in LiF:Mg,Cu, LiF:Mg,P and LiF:Mg,Cu,P detectors

International Nuclear Information System (INIS)

Mohammadi, Kh.; Moussavi Zarandi, A.; Afarideh, H.; Shahmaleki, S.

2013-01-01

In this study, electronic structure of LiF crystal doped with Mg,Cu,P impurities was studied with WIEN2k code on the basis of FPLAPW+lo method. Results show that in Mg-doped LiF composition, an electronic trap was created with impurity concentration of 1.56% and 3.125%. In this condition, the electronic trap with increasing the percentage of the impurities up to 4.687% is annihilated. It was found, that by doping of Mg and Cu or P simultaneously, a hole-trap is created in valence band. It was realized that in LiF:Mg,Cu, LiF:Mg,P and LiF:Mg,Cu,P, Cu impurity and Li atom, have a key role in creation of levels which lead to create electronic and hole traps. Mg impurity and F atom, only have a role in creation of electronic traps. In addition, P impurity has a main role in creation of the electronic and hole traps in LiF:Mg,Cu,P. The activation energy of electronic and hole trap in LiF:Mg,Cu, LiF:Mg,P and LiF:Mg,Cu,P crystalline lattice were obtained as 0.3 and 5.5 eV, 0.92 and 3.4 eV and 0.75 and 3.1 eV, respectively. - Graphical abstract: Figure (a) and (b) shows changes in electronic structure and band gap energy of LiF crystal due to presence of Mg and Cu, Mg and P ions respectively. - Highlights: • Electronic structure of LiF, LiF:Mg,Cu, LiF:Mg,P and LiF:Mg,Cu,P materials were studied with WIEN2K code. • In LiF:Mg,Cu and LiF:Mg,Cu,P, Li atom and Cu impurity have a key role in creation of levels. • F atom and Mg impurity only have a role in creation of electronic traps. • In LiF:Mg,Cu,P, P impurity has a main role in creation of electronic and hole traps

77 FR 37356 - Safety Zone for Fireworks Display, Pamlico River; Washington, NC

Science.gov (United States)

2012-06-21

... 1625-AA00 Safety Zone for Fireworks Display, Pamlico River; Washington, NC AGENCY: Coast Guard, DHS... life and property of the maritime public from the hazards posed by fireworks displays. This zone is... 300th Anniversary Celebration Fireworks. DATES: Comments and related material must be received by the...

Enhanced cycling stability of Li-rich nanotube cathodes by 3D graphene hierarchical architectures for Li-ion batteries

International Nuclear Information System (INIS)

Ma, Dingtao; Li, Yongliang; Wu, Maosheng; Deng, Libo; Ren, Xiangzhong; Zhang, Peixin

2016-01-01

A hybrid composite of Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 nanotubes (LMNCO NTs) wrapped with reduced graphene oxide (RGO) nanosheets (LMNCO@RGO) was prepared as cathode for lithium-ion batteries. The discharge capacity of the LMNCO@RGO composite is only reducing 3.5% after 100 cycles at 1 C. Such composite which simultaneously combines a high surface area of LMNCO NTs with shorten ionic diffusion pathway and high conductivity of 3D graphene hierarchical architectures as well as structural protection layers, displaying a good cycling stability.

Electrochemical reactions of the Th4+/Th couple on the tungsten, aluminum and bismuth electrodes in chloride molten salt

International Nuclear Information System (INIS)

Liu, Kui; Yuan, Li-Yong; Liu, Ya-Lan; Zhao, Xiu-Liang; He, Hui; Ye, Guo-An; Chai, Zhi-Fang; Shi, Wei-Qun

2014-01-01

This work concerns the electrochemical behaviors of Th 4+ on the tungsten, aluminum and bismuth electrodes in the LiCl-KCl eutectic, respectively, at 773 K. Cyclic voltammetry and square wave voltammetry were employed to investigate the cathodic reduction of Th 4+ . The results demonstrate that the reduction of Th 4+ is a one step process with a transfer of 4 electrons. The reversibility of the Th 4+ /Th couple on the bismuth film and tungsten electrodes is directly confirmed by the CV. The diffusion coefficient is also calculated to be (2.23 ± 0.16) × 10 −5 and (7.19 ± 0.12) × 10 −5 cm 2 /s by applying both cyclic voltammetry and chronopotentiometry, respectively. A series of redox couples were confirmed to be associated with the formation of different kinds of Al-Th intermetallic compounds. Compared to Al electrode, a cathodic shift of the reduction potential of the Th 4+ is observed on the Al film electrode which is not conducive for the potentiostatic extraction of thorium. The cathodic depolarization gives a shift of 420 mV on the Al electrode, while 490 mV on the Bi film electrode for the reduction of Th 4+ compared to the inert W electrode. The reduction potential of Th 4+ on the Bi film electrode is 70 mV more anodic than that on the Al electrode. Potentiostatic electrolyses were carried out on an Al plate and Bi liquid electrode to confirm the formation of the Th alloys. Two Al-Th alloys (Al 3 Th and Al 2 Th) and one Bi-Th alloy (Bi 2 Th) were obtained, respectively

Mass of 11Li from the 1H(11Li,9Li)3H reaction

International Nuclear Information System (INIS)

Roger, T.; Savajols, H.; Mittig, W.; Caamano, M.; Roussel-Chomaz, P.; Tanihata, I.; Alcorta, M.; Bandyopadhyay, D.; Bieri, R.; Buchmann, L.; Davids, B.; Galinski, N.; Howell, D.; Mills, W.; Mythili, S.; Openshaw, R.; Padilla-Rodal, E.; Ruprecht, G.; Sheffer, G.; Shotter, A. C.

2009-01-01

The mass of 11 Li has been determined from Q-value measurements of the 1 H( 11 Li, 9 Li) 3 H reaction. The experiment was performed at TRIUMF laboratory with the GANIL active target MAYA. Energy-energy and angle-angle kinematics reconstruction give a Q value of 8.119(22) MeV for the reaction. The derived 11 Li two-neutron separation energy is S 2n =363(22) keV

Thermal Stability of LiPF6 Salt and Li-ion Battery Electrolytes Containing LiPF6

OpenAIRE

Yang, Hui; Zhuang, Guorong V.; Ross Jr., Philip N.

2006-01-01

The thermal stability of the neat LiPF6 salt and of 1 molal solutions of LiPF6 in prototypical Li-ion battery solvents was studied with thermogravimetric analysis (TGA) and on-line FTIR. Pure LiPF6 salt is thermally stable up to 380 oK in a dry inert atmosphere, and its decomposition path is a simple dissociation producing LiF as solid and PF5 as gaseous products. In the presence of water (300 ppm) in the carrier gas, its decomposition onset temperature is lowered as a result of direct t...

Electrochemical behavior and stability of a commercial activated carbon in various organic electrolyte combinations containing Li-salts

International Nuclear Information System (INIS)

Zhang, Tong; Fuchs, Bettina; Secchiaroli, Marco; Wohlfahrt-Mehrens, Margret; Dsoke, Sonia

2016-01-01

Highlights: • 1 M LiPF 6 in PC displays the widest electrochemical stability window among others couples electrolyte/activated carbon. • Electrolytes based on EC-DMC show lower impedance than electrolytes containing PC. • 1 M LiPF 6 in PC has the highest cycling stability with 75% of capacitance retention after 20 000 cycles. - Abstract: The fast development of Li-ion capacitor (LIC) technologies requires the use of low resistance and stable electrolytes. An electrolyte for a LIC not only has to provide Li for the intercalation/deintercalation of the battery-type materials, but it also needs to be compatible with the supercapacitor material. Before designing a hybrid Li-ion capacitor device containing Li-insertion and double layer-type materials, it is necessary to understand and separate the contribution of each electrode material to the resistance, capacity and stability in the chosen electrolyte. Due to the intensive research on Li-ion batteries, the interactions of Li-salt containing electrolytes combined with Li insertion materials have been extensively investigated, and a lot of literature is available on this field. In contrast, there is only little knowledge about the exclusive interaction and compatibility of Li containing electrolytes with supercapacitor-type electrode materials (in absence of battery materials). With this purpose, this paper explores the electrochemical performance of electrodes based on commercial activated carbon (AC) in various lithium salt-containing electrolytes. A standard electrolyte for Li-ion batteries (1 M LiPF 6 in EC:DMC, 1:1) is evaluated and compared with an electrolyte prepared with the same salt dissolved in propylene carbonate (1 M LiPF 6 in PC) which is a solvent typically used in commercial supercapacitors. Furthermore, two new electrolyte solutions are proposed, based on a blend of salts 0.8 M LiPF 6 + 0.2 M NEt 4 BF 4 in EC:DMC (1:1) as well as in pure PC. The effect of the electrolyte composition is evaluated

Comparative Investigation of 0.5Li2MnO3·0.5LiNi0.5Co0.2Mn0.3O2 Cathode Materials Synthesized by Using Different Lithium Sources

Directory of Open Access Journals (Sweden)

Peng-Bo Wang

2018-05-01

Full Text Available Lithium-rich manganese-based cathode materials has been attracted enormous interests as one of the most promising candidates of cathode materials for next-generation lithium ion batteries because of its high theoretic capacity and low cost. In this study, 0.5Li2MnO3·0.5LiNi0.5Co0.2Mn0.3O2 materials are synthesized through a solid-state reaction by using different lithium sources, and the synthesis process and the reaction mechanism are investigated in detail. The morphology, structure, and electrochemical performances of the material synthesized by using LiOH·H2O, Li2CO3, and CH3COOLi·2H2O have been analyzed by using Thermo gravimetric analysis (TGA, X-ray diffraction (XRD, Scanning electron microscope (SEM, Transmission electron microscope (TEM, X-ray photoelectron spectroscopy (XPS, and electrochemical measurements. The 0.5Li2MnO3·0.5LiNi0.5Co0.2Mn0.3O2 material prepared by using LiOH·H2O displays uniform morphology with nano particle and stable layer structure so that it suppresses the first cycle irreversible reaction and structure transfer, and it delivers the best electrochemical performance. The results indicate that LiOH·H2O is the best choice for the synthesis of the 0.5Li2MnO3·0.5LiNi0.5Co0.2Mn0.3O2 material.

Pre-main-sequence depletion of Li-6 and Li-7

International Nuclear Information System (INIS)

Proffitt, C.R.; Michaud, G.

1989-01-01

Depletion of Li-6 and Li-7 during premain-sequence contraction has been calculated for several evolutionary sequences. Slightly greater Li-7 depletion was found than by other recent workers. On the premain sequence, Li-6 is depleted by a factor of at least 10 in the present models for stars with T(eff) lower than 6800 K on the main sequence. Because of the shorter destruction time scale for Li-6 as compared to Li-7, the determination of the abundances of these two isotopes would place strict constraints on the structure of premain-sequence stars. 39 refs

Liquid crystals beyond displays chemistry, physics, and applications

CERN Document Server

Li, Quan

2012-01-01

The chemistry, physics, and applications of liquid crystals beyond LCDs Liquid Crystals (LCs) combine order and mobility on a molecular and supramolecular level. But while these remarkable states of matter are most commonly associated with visual display technologies, they have important applications for a variety of other fields as well. Liquid Crystals Beyond Displays: Chemistry, Physics, and Applications considers these, bringing together cutting-edge research from some of the most promising areas of LC science. Featuring contributions from respected researchers from around the globe, th

Fabrication and characterization of 6Li-enriched Li2TiO3 pebbles for a high Li-burnup irradiation test

International Nuclear Information System (INIS)

Tsuchiya, Kunihiko; Kawamura, Hiroshi

2006-10-01

Lithium titanate (Li 2 TiO 3 ) pebbles are considered to be a candidate material of tritium breeders for fusion reactor from viewpoints of easy tritium release at low temperatures (about 300degC) and chemical stability. In the present study, trial fabrication tests of 6 Li-enriched Li 2 TiO 3 pebbles of 1mm in diameter were carried out by a wet process with a dehydration reaction, and characteristics of the 6 Li-enriched Li 2 TiO 3 pebbles were evaluated for preparation of a high Li-burnup test in a testing reactor. Powder of 96at% 6 Li-enriched Li 2 TiO 3 was prepared by a solid state reaction, and two kinds of 6 Li-enriched Li 2 TiO 3 pebbles, namely un-doped and TiO 2 -doped Li 2 TiO 3 pebbles, were fabricated by the wet process. Based on results of the pebble fabrication tests, two kinds of 6 Li-enriched Li 2 TiO 3 pebbles were successfully fabricated with target values (density: 80-85%T.D., grain size: 2 TiO 3 pebbles was a satisfying value of about 1.05. Contact strength of these pebbles was about 6300MPa, which was almost the same as that of the Li 2 TiO 3 pebbles with natural Li. (author)

A hydrothermally synthesized LiFePO4/C composite with superior low-temperature performance and cycle life

Science.gov (United States)

Wu, Guan; Liu, Na; Gao, Xuguang; Tian, Xiaohui; Zhu, Yanbin; Zhou, Yingke; Zhu, Qingyou

2018-03-01

The LiFePO4/C composites have been successfully synthesized by a hydrothermal process, with the combined carbon sources of fructose and calcium lignosulfonate. The morphology and microstructure of LiFePO4/C were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The electrochemical properties were evaluated by the constant-current charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy. The uniform carbon coating layer derived from calcium lignosulfonate can effectively improve the electronic conductivity, lithium-ion diffusivity and surface stability of the LiFePO4/C composites and prevent the side reactions between the LiFePO4 particles and electrolytes. The LiFePO4/C composites display excellent rate capability, superior cycle life and outstanding low temperature performance, which are promising for lithium-ion battery applications in electrical vehicles and electrical energy storage systems.

Psychometric properties for the Balanced Inventory of Desirable Responding: dichotomous versus polytomous conventional and IRT scoring.

Science.gov (United States)

Vispoel, Walter P; Kim, Han Yi

2014-09-01

[Correction Notice: An Erratum for this article was reported in Vol 26(3) of Psychological Assessment (see record 2014-16017-001). The mean, standard deviation and alpha coefficient originally reported in Table 1 should be 74.317, 10.214 and .802, respectively. The validity coefficients in the last column of Table 4 are affected as well. Correcting this error did not change the substantive interpretations of the results, but did increase the mean, standard deviation, alpha coefficient, and validity coefficients reported for the Honesty subscale in the text and in Tables 1 and 4. The corrected versions of Tables 1 and Table 4 are shown in the erratum.] Item response theory (IRT) models were applied to dichotomous and polytomous scoring of the Self-Deceptive Enhancement and Impression Management subscales of the Balanced Inventory of Desirable Responding (Paulhus, 1991, 1999). Two dichotomous scoring methods reflecting exaggerated endorsement and exaggerated denial of socially desirable behaviors were examined. The 1- and 2-parameter logistic models (1PLM, 2PLM, respectively) were applied to dichotomous responses, and the partial credit model (PCM) and graded response model (GRM) were applied to polytomous responses. For both subscales, the 2PLM fit dichotomous responses better than did the 1PLM, and the GRM fit polytomous responses better than did the PCM. Polytomous GRM and raw scores for both subscales yielded higher test-retest and convergent validity coefficients than did PCM, 1PLM, 2PLM, and dichotomous raw scores. Information plots showed that the GRM provided consistently high measurement precision that was superior to that of all other IRT models over the full range of both construct continuums. Dichotomous scores reflecting exaggerated endorsement of socially desirable behaviors provided noticeably weak precision at low levels of the construct continuums, calling into question the use of such scores for detecting instances of "faking bad." Dichotomous

Investigation of tritium and 233U breeding in a fission-fusion hybrid reactor fuelling with ThO2

International Nuclear Information System (INIS)

Yildiz, K.; Sahin, S.; Sahin, H. M.; Acir, A.; Yalcin, S.; Altinok, T.; Bayrak, M.; Alkan, M.; Durukan, O.

2007-01-01

In the world, thorium reserves are three times more than natural Uranium reserves. It is planned in the near future that nuclear reactors will use thorium as a fuel. Thorium is not a fissile isotope because it doesn't make fission with thermal neutrons so it could be converted to 2 33U isotope which has very high quality fission cross-section with thermal neutrons. 2 33U isotope can be used in present LWRs as an enrichment fuel. In the fusion reactors, tritium is the most important fossil fuel. Because tritium is not natural isotope, it has to be produced in the reactor. The purpose of this work is to investigate the tritium and 2 33U breeding in a fission-fusion hybrid reactor fuelling with ThO 2 for Δt=10 days during a reactor operation period in five years. The neutronic analysis is performed on an experimental hybrid blanket geometry. In the center of the hybrid blanket, there is a line neutron source in a cylindrical cavity, which simulates the fusion plasma chamber where high energy neutrons (14.1 MeV) are produced. The conventional fusion reaction delivers the external neutron source for blankets following, 2 D + 3 T →? 4 He (3.5 MeV) + n (14.1 MeV). (1) The fuel zone made up of natural-ThO 2 fuel and it is cooled with different coolants. In this work, five different moderator materials, which are Li 2 BeF 4 , LiF-NaF-BeF 2 , Li 2 0Sn 8 0, natural Lithium and Li 1 7Pb 8 3, are used as coolants. The radial reflector, called tritium breeding zones, is made of different Lithium compounds and graphite in sandwich structure. In the work, eight different Lithium compounds were used as tritium breeders in the tritium breeding zones, which are Li 3 N, Li 2 O, Li 2 O 2 , Li 2 TiO 3 , Li 4 SiO 3 , Li 2 ZrO 3 , LiBr and LiH. Neutron transport calculations are conducted in spherical geometry with the help of SCALE4.4A SYSTEM by solving the Boltzmann transport equation with code CSAS and XSDRNPM, under consideration of unresolved and resolved resonances, in S 8 -P 3

Kinetic Monte Carlo Study of Li Intercalation in LiFePO4.

Science.gov (United States)

Xiao, Penghao; Henkelman, Graeme

2018-01-23

Even as a commercial cathode material, LiFePO 4 remains of tremendous research interest for understanding Li intercalation dynamics. The partially lithiated material spontaneously separates into Li-poor and Li-rich phases at equilibrium. Phase segregation is a surprising property of LiFePO 4 given its high measured rate capability. Previous theoretical studies, aiming to describe Li intercalation in LiFePO 4 , include both atomic-scale density functional theory (DFT) calculations of static Li distributions and entire-particle-scale phase field models, based upon empirical parameters, studying the dynamics of the phase separation. Little effort has been made to bridge the gap between these two scales. In this work, DFT calculations are used to fit a cluster expansion for the basis of kinetic Monte Carlo calculations, which enables long time scale simulations with accurate atomic interactions. This atomistic model shows how the phases evolve in Li x FePO 4 without parameters from experiments. Our simulations reveal that an ordered Li 0.5 FePO4 phase with alternating Li-rich and Li-poor planes along the ac direction forms between the LiFePO 4 and FePO 4 phases, which is consistent with recent X-ray diffraction experiments showing peaks associated with an intermediate-Li phase. The calculations also help to explain a recent puzzling experiment showing that LiFePO 4 particles with high aspect ratios that are narrower along the [100] direction, perpendicular to the [010] Li diffusion channels, actually have better rate capabilities. Our calculations show that lateral surfaces parallel to the Li diffusion channels, as well as other preexisting sites that bind Li weakly, are important for phase nucleation and rapid cycling performance.

Thermal stability of LiPF 6 salt and Li-ion battery electrolytes containing LiPF 6

Science.gov (United States)

Yang, Hui; Zhuang, Guorong V.; Ross, Philip N.

The thermal stability of the neat lithium hexafluorophosphate (LiPF 6) salt and of 1 molal (m) solutions of LiPF 6 in prototypical Li-ion battery solvents was studied with thermogravimetric analysis (TGA) and on-line Fourier transform infrared (FTIR). Pure LiPF 6 salt is thermally stable up to 107 °C in a dry inert atmosphere, and its decomposition path is a simple dissociation producing lithium fluoride (LiF) as solid and PF 5 as gaseous products. In the presence of water (300 ppm) in the carrier gas, its decomposition onset temperature is lowered as a result of direct thermal reaction between LiPF 6 and water vapor to form phosphorous oxyfluoride (POF 3) and hydrofluoric acid (HF). No new products were observed in 1 m solutions of LiPF 6 in ethylene carbonate (EC), dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC) by on-line TGA-FTIR analysis. The storage of the same solutions in sealed containers at 85 °C for 300-420 h did not produce any significant quantity of new products as well. In particular, no alkylflurophosphates were found in the solutions after storage at elevated temperature. In the absence of either an impurity like alcohol or cathode active material that may (or may not) act as a catalyst, there is no evidence of thermally induced reaction between LiPF 6 and the prototypical Li-ion battery solvents EC, PC, DMC or EMC.

Water vapor concentration dependence and temperature dependence of Li mass loss from Li{sub 2}TiO{sub 3} with excess Li and Li{sub 4}SiO{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Shimozori, Motoki [Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1, Kasugakoen, Kasuga, Fukuoka 816-8580 (Japan); Katayama, Kazunari, E-mail: kadzu@nucl.kyushu-u.ac.jp [Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1, Kasugakoen, Kasuga, Fukuoka 816-8580 (Japan); Hoshino, Tsuyoshi [Breeding Functional Materials Development Group, Department of Blanket Systems Research, Rokkasho Fusion Institute, Sector of Fusion Research and Development, Japan Atomic Energy Agency, 2-166 Obuch, Omotedate, Rokkasho-mura, Kamikita-gun, Aomori 039-3212 (Japan); Ushida, Hiroki; Yamamoto, Ryotaro; Fukada, Satoshi [Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1, Kasugakoen, Kasuga, Fukuoka 816-8580 (Japan)

2015-10-15

Highlights: • Li mass loss from Li{sub 2.11}TiO{sub 3} increased proportionally to water vapor pressure. • Li mass loss from Li{sub 2.11}TiO{sub 3} at 600 °C was significantly smaller than expected. • Differences of Li mass loss behavior from Li{sub 2.11}TiO{sub 3} and Li{sub 4}SiO{sub 4} were shown. - Abstract: In this study, weight reduction of Li{sub 2}TiO{sub 3} with excess Li and Li{sub 4}SiO{sub 4} at elevated temperatures under hydrogen atmosphere or water vapor atmosphere was investigated. The Li mass loss for the Li{sub 2}TiO{sub 3} at 900 °C was 0.4 wt% under 1000 Pa H{sub 2} atmosphere and 1.5 wt% under 50 Pa H{sub 2}O atmosphere. The Li mass loss for the Li{sub 2}TiO{sub 3} increased proportionally to the water vapor pressure in the range from 50 to 200 Pa at 900 °C and increased with increasing temperature from 700 to 900 °C although Li mass loss at 600 °C was significantly smaller than expected. It was found that water vapor concentration dependence and temperature dependence of Li mass loss for the Li{sub 2}TiO{sub 3} and the Li{sub 4}SiO{sub 4} used in this work were quite different. Water vapor is released from the ceramic breeder materials into the purge gas due to desorption of adsorbed water and water formation reaction. The released water vapor possibly promotes Li mass loss with the formation of LiOH on the surface.

Recovery of Li from alloys of Al- Li and Li- Al using engineered scavenger compounds

Science.gov (United States)

Riley, W. D.; Jong, B. W.; Collins, W. K.; Gerdemann, S. J.

1994-01-01

A method of producing lithium of high purity from lithium aluminum alloys using an engineered scavenger compound, comprising: I) preparing an engineered scavenger compound by: a) mixing and heating compounds of TiO2 and Li2CO3 at a temperature sufficient to dry the compounds and convert Li.sub.2 CO.sub.3 to Li.sub.2 O; and b) mixing and heating the compounds at a temperature sufficient to produce a scavenger Li.sub.2 O.3TiO.sub.2 compound; II) loading the scavenger into one of two electrode baskets in a three electrode cell reactor and placing an Al-Li alloy in a second electrode basket of the three electrode cell reactor; III) heating the cell to a temperature sufficient to enable a mixture of KCl-LiCl contained in a crucible in the cell to reach its melting point and become a molten bath; IV) immersing the baskets in the bath until an electrical connection is made between the baskets to charge the scavenger compound with Li until there is an initial current and voltage followed by a fall off ending current and voltage; and V) making a connection between the basket electrode containing engineered scavenger compound and a steel rod electrode disposed between the basket electrodes and applying a current to cause Li to leave the scavenger compound and become electrodeposited on the steel rod electrode.

EPR experiments in LiTbF4, LiHoF4, and LiErF4 at submillimeter frequencies

DEFF Research Database (Denmark)

Magariño, J.; Tuchendler, J.; Beauvillain, P.

1980-01-01

Electron-paramagnetic-resonance experiments in LiTbF4, LiHoF4, and LiErF4 have been performed at frequencies between 70 and 600 GHz, in magnetic fields up to 60 kG and in the temperature range 1.4......Electron-paramagnetic-resonance experiments in LiTbF4, LiHoF4, and LiErF4 have been performed at frequencies between 70 and 600 GHz, in magnetic fields up to 60 kG and in the temperature range 1.4...

Absorption of water vapour in the falling film of water-(LiBr + LiI + LiNO{sub 3} + LiCl) in a vertical tube at air-cooling thermal conditions

Energy Technology Data Exchange (ETDEWEB)

Bourouis, Mahmoud; Valles, Manel; Medrano, Marc; Coronas, Alberto [Centro de Innovacion Tecnologica en Revalorizacion Energetica y Refrigeracion, CREVER, Universitat Rovira i Virgili, Autovia de Salou, s/n, 43006, Tarragona (Spain)

2005-05-01

In air-cooled water-LiBr absorption chillers the working conditions in the absorber and condenser are shifted to higher temperatures and concentrations, thereby increasing the risk of crystallisation. To develop this technology, two main problems are to be addressed: the availability of new salt mixtures with wider range of solubility than water-LiBr, and advanced absorber configurations that enable to carry out simultaneously an appropriate absorption process and an effective air-cooling. One way of improving the solubility of LiBr aqueous solutions is to add other salts to create multicomponent salt solutions. The aqueous solution of the quaternary salt system (LiBr + LiI + LiNO{sub 3} + LiCl) presents favourable properties required for air-cooled absorption systems: less corrosive and crystallisation temperature about 35 K lower than that of water-LiBr.This paper presents an experimental study on the absorption of water vapour over a wavy laminar falling film of an aqueous solution of (LiBr + LiI + LiNO{sub 3} + LiCl) on the inner wall of a water-cooled smooth vertical tube. Cooling water temperatures in the range 30-45 C were selected to simulate air-cooling thermal conditions. The results are compared with those obtained in the same experimental set-up with water-LiBr solutions.The control variables for the experimental study were: absorber pressure, solution Reynolds number, solution concentration and cooling water temperature. The parameters considered to assess the absorber performance were: absorber thermal load, mass absorption flux, degree of subcooling of the solution leaving the absorber, and the falling film heat transfer coefficient.The higher solubility of the multicomponent salt solution makes possible the operation of the absorber at higher salt concentration than with the conventional working fluid water-LiBr. The absorption fluxes achieved with water-(LiBr + LiI + LiNO{sub 3} + LiCl) at a concentration of 64.2 wt% are around 60 % higher than

Effect of Al in the H2 storage properties of Li-NH system

International Nuclear Information System (INIS)

Fernandez Albanesi, L; Lago, Marcelo N; Arneodo Larochette, P; Gennari, F.C

2012-01-01

In this work is studied the effect of the addition of aluminum on the properties of hydrogen absorption-desorption system LiNH 2 : 1,5 LiH. The samples were prepared adding the element Al to the system LiNH 2 :1.5 LiH in different ways (as aluminum metal, as aluminum chloride and as lithium aluminum hydride). In all these mixtures was maintained the concentration of Al in 1 mol%. A good distribution of Al is achieved by mechanical milling. Quantitative hydrogen absorption and desorption were measured by volumetric method with a Sieverts-type apparatus in the temperature range of 250 to 300 o C and 700 kPa of H 2 pressure. The systems with Al showed better absorption kinetics and greater stability after cycles of hydrogen absorption-desorption. The hydrogen capacity achieved by these samples was 5.3 wt% at 300 and 275 o C. The mixture with AlCl 3 displays the same characteristics at 250 o C, showing the better H 2 storage properties

New Visualization Techniques to Analyze Ultra-High Resolution Four-dimensional Surface Deformation Imagery Collected With Ground-based Tripod LiDAR

Science.gov (United States)

Kreylos, O.; Bawden, G. W.; Kellogg, L. H.

2005-12-01

We are developing a visualization application to display and interact with very large (tens of millions of points) four-dimensional point position datasets in an immersive environment such that point groups from repeated Tripod LiDAR (Light Detection And Ranging) surveys can be selected, measured, and analyzed for land surface change using 3D~interactions. Ground-based tripod or terrestrial LiDAR (T-LiDAR) can remotely collect ultra-high resolution (centimeter to subcentimeter) and accurate (± 4 mm) digital imagery of the scanned target, and at scanning rates of 2,000 (x, y, z, i) (3D~position~+ intensity) points per second over 7~million points can be collected for a given target in an hour. We developed a multiresolution point set data representation based on octrees to display large T-LiDAR point cloud datasets at the frame rates required for immersive display (between 60 Hz and 120 Hz). Data inside an observer's region of interest is shown in full detail, whereas data outside the field of view or far away from the observer is shown at reduced resolution to provide context. Using 3D input devices at the University of California Davis KeckCAVES, users can navigate large point sets, accurately select related point groups in two or more point sets by sweeping regions of space, and guide the software in deriving positional information from point groups to compute their displacements between surveys. We used this new software application in the KeckCAVES to analyze 4D T-LiDAR imagery from the June~1, 2005 Blue Bird Canyon landslide in Laguna Beach, southern California. Over 50~million (x, y, z, i) data points were collected between 10 and 21~days after the landslide to evaluate T-LiDAR as a natural hazards response tool. The visualization of the T-LiDAR scans within the immediate landslide showed minor readjustments in the weeks following the primarily landslide with no observable continued motion on the primary landslide. Recovery and demolition efforts across the

Effects of PARP-1 Deficiency on Th1 and Th2 Cell Differentiation

Directory of Open Access Journals (Sweden)

M. Sambucci

2013-01-01

Full Text Available T cell differentiation to effector Th cells such as Th1 and Th2 requires the integration of multiple synergic and antagonist signals. Poly(ADP-ribosylation is a posttranslational modification of proteins catalyzed by Poly(ADP-ribose polymerases (PARPs. Recently, many reports showed that PARP-1, the prototypical member of the PARP family, plays a role in immune/inflammatory responses. Consistently, its enzymatic inhibition confers protection in several models of immune-mediated diseases, mainly through an inhibitory effect on NF-κB (and NFAT activation. PARP-1 regulates cell functions in many types of immune cells, including dendritic cells, macrophages, and T and B lymphocytes. Our results show that PARP-1KO cells displayed a reduced ability to differentiate in Th2 cells. Under both nonskewing and Th2-polarizing conditions, naïve CD4 cells from PARP-1KO mice generated a reduced frequency of IL-4+ cells, produced less IL-5, and expressed GATA-3 at lower levels compared with cells from wild type mice. Conversely, PARP-1 deficiency did not substantially affect differentiation to Th1 cells. Indeed, the frequency of IFN-γ+ cells as well as IFN-γ production, in nonskewing and Th1-polarizing conditions, was not affected by PARP-1 gene ablation. These findings demonstrate that PARP-1 plays a relevant role in Th2 cell differentiation and it might be a target to be exploited for the modulation of Th2-dependent immune-mediated diseases.

Rapid charge-discharge property of Li4Ti5O12-TiO2 nanosheet and nanotube composites as anode material for power lithium-ion batteries.

Science.gov (United States)

Yi, Ting-Feng; Fang, Zi-Kui; Xie, Ying; Zhu, Yan-Rong; Yang, Shuang-Yuan

2014-11-26

Well-defined Li4Ti5O12-TiO2 nanosheet and nanotube composites have been synthesized by a solvothermal process. The combination of in situ generated rutile-TiO2 in Li4Ti5O12 nanosheets or nanotubes is favorable for reducing the electrode polarization, and Li4Ti5O12-TiO2 nanocomposites show faster lithium insertion/extraction kinetics than that of pristine Li4Ti5O12 during cycling. Li4Ti5O12-TiO2 electrodes also display lower charge-transfer resistance and higher lithium diffusion coefficients than pristine Li4Ti5O12. Therefore, Li4Ti5O12-TiO2 electrodes display lower charge-transfer resistance and higher lithium diffusion coefficients. This reveals that the in situ TiO2 modification improves the electronic conductivity and electrochemical activity of the electrode in the local environment, resulting in its relatively higher capacity at high charge-discharge rate. Li4Ti5O12-TiO2 nanocomposite with a Li/Ti ratio of 3.8:5 exhibits the lowest charge-transfer resistance and the highest lithium diffusion coefficient among all samples, and it shows a much improved rate capability and specific capacity in comparison with pristine Li4Ti5O12 when charging and discharging at a 10 C rate. The improved high-rate capability, cycling stability, and fast charge-discharge performance of Li4Ti5O12-TiO2 nanocomposites can be ascribed to the improvement of electrochemical reversibility, lithium ion diffusion, and conductivity by in situ TiO2 modification.

Ultralong Lifespan and Ultrafast Li Storage: Single-Crystal LiFePO4 Nanomeshes.

Science.gov (United States)

Zhang, Yan; Zhang, Hui Juan; Feng, Yang Yang; Fang, Ling; Wang, Yu

2016-01-27

A novel LiFePO4 material, in the shape of a nanomesh, has been rationally designed and synthesized based on the low crystal-mismatch strategy. The LiFePO4 nanomesh possesses several advantages in morphology and crystal structure, including a mesoporous structure, its crystal orientation that is along the [010] direction, and a shortened Li-ion diffusion path. These properties are favorable for their application as cathode in Li-ion batteries, as these will accelerate the Li-ion diffusion rate, improve the Li-ion exchange between the LiFePO4 nanomesh and the electrolyte, and reduce the Li-ion capacitive behavior during Li intercalation. So the LiFePO4 nanomesh exhibits a high specific capacity, enhanced rate capability, and strengthened cyclability. The method developed here can also be extended to other similar systems, for instance, LiMnPO4 , LiCoPO4 , and LiNiPO4 , and may find more applications in the designed synthesis of functional materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Real-time Image Generation for Compressive Light Field Displays

International Nuclear Information System (INIS)

Wetzstein, G; Lanman, D; Hirsch, M; Raskar, R

2013-01-01

With the invention of integral imaging and parallax barriers in the beginning of the 20th century, glasses-free 3D displays have become feasible. Only today—more than a century later—glasses-free 3D displays are finally emerging in the consumer market. The technologies being employed in current-generation devices, however, are fundamentally the same as what was invented 100 years ago. With rapid advances in optical fabrication, digital processing power, and computational perception, a new generation of display technology is emerging: compressive displays exploring the co-design of optical elements and computational processing while taking particular characteristics of the human visual system into account. In this paper, we discuss real-time implementation strategies for emerging compressive light field displays. We consider displays composed of multiple stacked layers of light-attenuating or polarization-rotating layers, such as LCDs. The involved image generation requires iterative tomographic image synthesis. We demonstrate that, for the case of light field display, computed tomographic light field synthesis maps well to operations included in the standard graphics pipeline, facilitating efficient GPU-based implementations with real-time framerates.

Distinct DC subsets regulate adaptive Th1 and 2 responses during Trichuris muris infection

DEFF Research Database (Denmark)

Demiri, M.; Müller-Luda, K.; Agace, William Winston

2017-01-01

a high-dose infection and displayed impaired Th2 responses. Conversely, mice lacking IRF8-dependent cDC cleared a low-dose infection and displayed an impaired Th1 response while increased production of Th2 cytokines. Finally, mice lacking both IRF4- and IRF8-dependent cDC were able to generate a Th2...... response and clear a low-dose infection. Collectively, these results suggest that IRF4- and IRF8-dependent cDC act antagonistically during T. muris infection, and demonstrate that intestinal Th2 responses can be generated towards T. muris in the absence of IRF4-dependent cDC.......Low- and high-dose infections with the murine large intestinal nematode Trichuris muris are associated with induction of adaptive Th1 and Th2 responses, respectively, in mesenteric lymph nodes (MLN). Classical dendritic cells (cDC) accumulate in the large intestinal mucosa and MLN upon T. muris...

Pixels, people, perception, pet peeves, and possibilities: a look at displays

Science.gov (United States)

Task, H. Lee

2007-04-01

This year marks the 35 th anniversary of the Visually Coupled Systems symposium held at Brooks Air Force Base, San Antonio, Texas in November of 1972. This paper uses the proceedings of the 1972 VCS symposium as a guide to address several topics associated primarily with helmet-mounted displays, systems integration and the human-machine interface. Specific topics addressed include monocular and binocular helmet-mounted displays (HMDs), visor projection HMDs, color HMDs, system integration with aircraft windscreens, visual interface issues and others. In addition, this paper also addresses a few mysteries and irritations (pet peeves) collected over the past 35+ years of experience in the display and display related areas.

Evaluation of the microstructure of Al-Cu-Li-Ag-Mg Weldalite (tm) alloys, part 4

Science.gov (United States)

Pickens, Joseph R.; Kumar, K. S.; Brown, S. A.; Gayle, Frank W.

1991-01-01

Weldalite (trademark) 049 is an Al-Cu-Li-Ag-Mg alloy designed to have ultrahigh strength and to serve in aerospace applications. The alloy displays significantly higher strength than competitive alloys in both naturally aged and artificially aged tempers. The strengthening phases in such tempers have been identified to, in part, explain the mechanical properties attained. In general, the alloy is strengthened by delta prime Al3Li and Guinier-Preston (GP) zones in the naturally aged tempers. In artificially aged tempers in slightly underaged conditions, strengthening is provided by several phases including GP zones, theta prime Al2Cu, S prime Al2CuMg, T(sub 1) Al2CuLi, and possibly a new phase. In the peak strength artificially aged tempers, T(sub 1) is the predominant strengthening phase.

Coating effect of LiFePO4 and Al2O3 on Li1.2Mn0.54Ni0.13Co0.13O2 cathode surface for lithium ion batteries

Science.gov (United States)

Seteni, Bonani; Rapulenyane, Nomasonto; Ngila, Jane Catherine; Mpelane, Siyasanga; Luo, Hongze

2017-06-01

Lithium-manganese-rich cathode material Li1.2Mn0.54Ni0.13Co0.13O2 is prepared by combustion method, and then coated with nano-sized LiFePO4 and nano-sized Al2O3 particles via a wet chemical process. The as-prepared Li1.2Mn0.54Ni0.13Co0.13O2, LiFePO4-coated Li1.2Mn0.54Ni0.13Co0.13O2 and Al2O3-coated Li1.2Mn0.54Ni0.13Co0.13O2 are characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The scanning electron microscopy shows the agglomeration of the materials and their nanoparticle size ∼100 nm. The transmission electron microscopy confirms that LiFePO4 forms a rough mat-like surface and Al2O3 remain as islandic particles on the surface of the Li1.2Mn0.54Ni0.13Co0.13O2 material. The Li1.2Mn0.54Ni0.13Co0.13O2 coated with LiFePO4 and Li1.2Mn0.54Ni0.13Co0.13O2 coated with Al2O3 exhibits improved electrochemical performance. The initial discharge capacity is enhanced to 267 mAhg-1 after the LiFePO4 coating and 285 mAhg-1 after the Al2O3 coating compared to the as-prepared Li1.2Mn0.54Ni0.13Co0.13O2 material that has an initial discharge capacity of 243 mAhg-1. Galvanostatic charge-discharge tests at C/10 display longer activation of Li2MnO3 phase and higher capacity retention of 88% after 20 cycles for Li1.2Mn0.54Ni0.13Co0.13O2-LiFePO4 compared to Li1.2Mn0.54Ni0.13Co0.13O2-Al2O3 of 80% after 20 cycles and LMNC of 80% after 20 cycles. Meanwhile Li1.2Mn0.54Ni0.13Co0.13O2-LiFePO4 also shows higher rate capability compared to Li1.2Mn0.54Ni0.13Co0.13O2-Al2O3.

Optical Properties and Electrochemical Performance of LiFePO4 Thin Films Deposited on Transparent Current Collectors.

Science.gov (United States)

Lee, HyunSeok; Yim, Haena; Kim, Kwang-Bum; Choi, Ji-Won

2015-11-01

LiFePO4 thin film cathodes are deposited on various transparent conducting oxide thin films on glass, which are used as cathode current collectors. The XRD patterns show that the thin films have the phase of LiFePO4 with an ordered olivine structure indexed to the orthorhombic Pmna space group. LiFePO4 thin film deposited on various TCO glass substrates exhibits transmittance of about 53%. The initial specific discharge capacities of LiFePO4 thin films are 25.0 μAh/cm2 x μm on FTO, 33.0 μAh/cm2 x μm on ITO, and 13.0 μAh/cm2 x μm on AZO coated glass substrates. Interestingly, the retention capacities of LiFePO4 thin films are 76.0% on FTO, 31.2% on ITO, and 37.7% on AZO coated glass substrates at 20th cycle. The initial specific discharge capacity of the LiFePO4/FTO electrode is slightly lower, but the discharge capacities of the LiFePO4/FTO electrode relatively decrease less than those of the others such as LiFePO4/ITO and LiFePO4/AZO with cycling. The results reported here provide the high transparency of LiFePO4 thin films cathode materials and the good candidate as FTO current collector of the LiFePO4 thin film cathode of transparent thin film rechargeable batteries due to its high transparency and cyclic retention.

Uniform second Li ion intercalation in solid state ϵ-LiVOPO4

International Nuclear Information System (INIS)

Wangoh, Linda W.; Quackenbush, Nicholas F.; Sallis, Shawn; Wiaderek, Kamila M.; Ma, Lu; Wu, Tianpin; Chapman, Karena W.; Lin, Yuh-Chieh; Ong, Shyue Ping; Wen, Bohua; Chernova, Natasha A.; Whittingham, M. Stanley; Guo, Jinghua; Lee, Tien-Lin; Schlueter, Christoph; Piper, Louis F. J.

2016-01-01

Full, reversible intercalation of two Li + has not yet been achieved in promising VOPO 4 electrodes. A pronounced Li + gradient has been reported in the low voltage window (i.e., second lithium reaction) that is thought to originate from disrupted kinetics in the high voltage regime (i.e., first lithium reaction). Here, we employ a combination of hard and soft x–ray photoelectron and absorption spectroscopy techniques to depth profile solid state synthesized LiVOPO 4 cycled within the low voltage window only. Analysis of the vanadium environment revealed no evidence of a Li + gradient, which combined with almost full theoretical capacity confirms that disrupted kinetics in the high voltage window are responsible for hindering full two lithium insertion. Furthermore, we argue that the uniform Li + intercalation is a prerequisite for the formation of intermediate phases Li 1.50 VOPO 4 and Li 1.75 VOPO 4 . The evolution from LiVOPO 4 to Li 2 VOPO 4 via the intermediate phases is confirmed by direct comparison between O K–edge absorption spectroscopy and density functional theory.

Energy Awareness Displays - Prototype for personalised energy consumption feedback

NARCIS (Netherlands)

Börner, Dirk; Storm, Jeroen; Kalz, Marco; Specht, Marcus

2012-01-01

Börner, D., Storm, J., Kalz, M., & Specht, M. (2012). Energy Awareness Displays - Prototype for personalised energy consumption feedback. In A. Ravencroft, S. Lindstaedt, C. D. Kloos, & D. Hernández-Leo (Eds.), 21st Century Learning for 21st Century Skills - 7th European Conference on Technology

Ambient Displays and Game Design Patterns for Social Learning

NARCIS (Netherlands)

Kelle, Sebastian; Börner, Dirk; Kalz, Marco; Specht, Marcus; Glahn, Christian

2011-01-01

Kelle, S., Börner, D., Kalz, M., Specht, M., & Glahn, C. (2010). Ambient Displays and Game Design Patterns for Social Learning. In B. Chang, T. Hirashima, & H. Ogata (Eds.), Joint Proceedings of the Work-in-Progress Poster and Invited Young Researcher Symposium for the 18th International Conference

Low Cost Metal Carbide Nanocrystals as Binding and Electrocatalytic Sites for High Performance Li-S Batteries.

Science.gov (United States)

Zhou, Fei; Li, Zheng; Luo, Xuan; Wu, Tong; Jiang, Bin; Lu, Lei-Lei; Yao, Hong-Bin; Antonietti, Markus; Yu, Shu-Hong

2018-02-14

Lithium sulfur (Li-S) batteries are considered as promising energy storage systems for the next generation of batteries due to their high theoretical energy densities and low cost. Much effort has been made to improve the practical energy densities and cycling stability of Li-S batteries via diverse designs of materials nanostructure. However, achieving simultaneously good rate capabilities and stable cycling of Li-S batteries is still challenging. Herein, we propose a strategy to utilize a dual effect of metal carbide nanoparticles decorated on carbon nanofibers (MC NPs-CNFs) to realize high rate performance, low hysteresis, and long cycling stability of Li-S batteries in one system. The adsorption experiments of lithium polysulfides (LiPS) to MC NPs and corresponding theoretical calculations demonstrate that LiPS are likely to be adsorbed and diffused on the surface of MC NPs because of their moderate chemical bonding. MC NPs turn out to have also an electrocatalytic role and accelerate electrochemical redox reactions of LiPS, as proven by cyclic voltammetry analysis. The fabricated Li-S batteries based on the W 2 C NPs-CNFs hybrid electrodes display not only high specific capacity of 1200 mAh/g at 0.2C but also excellent rate performance and cycling stability, for example, a model setup can be operated at 1C for 500 cycles maintaining a final specific capacity of 605 mAh/g with a degradation rate as low as 0.06%/cycle.

Characteristics of new LiF preparations and sensitised LiF

Energy Technology Data Exchange (ETDEWEB)

Driscoll, C M.H.; O' Hagan, J B; Mundy, S J; Todd, C D; McWhan, A F; Dodson, J

1986-01-01

The patent governing the preparation and production of lithium fluoride (LiF) awarded to the Harshaw Chemical Co. has expired. Other companies have become interested in developing additional preparations of this material. Two of these preparations include LiF:Mg,Ti manufactured by Vinten Instruments plc and high sensitivity LiF:Mg, Cu,P distributed by them. The properties of these materials, including sensitivity, dose threshold, photon energy response, reusability and storage characteristics, are presented in this paper and compared with those of Harshaw TLD-100 and with those of sensitised LiF.

Experimental investigation of highly excited states of the 5,6He and 5,6Li nuclei in the (6Li, 7Be) and (6Li, 7Li) one-nucleon-pick-up reactions

International Nuclear Information System (INIS)

Sakuta, S.B.; Novatskij, B.G.; Stepanov, D.N.; Aleksandrov, D.V.; Glukhov, Yu.A.; Nikol'skij, E.Yu.

2002-01-01

( 6 Li, 7 Be) and ( 6 Li, 7 Li) reactions on the 6 Li, 7 Li nuclei have been investigated in the angular range of 0-20 deg in laboratory system at the 93-MeV 6 Li energy. Besides low-lying states of 5,6 He and 5,6 Li nuclei, broad structures have been observed in the measured spectra close to the t( 3 He) + d and t( 3 He) + t threshold at excitation energies of 16.75 (3/2 + ) and ∼ 20 MeV ( 5 He), 16.66 (3/2 + ) and ∼ 20 MeV ( 5 Li), 14.0 and 25 MeV ( 6 He), and ∼ 20 MeV ( 6 Li). Angular distributions, which have been measured for transitions to the ground (0 + ) and exited states at E x =1.8 MeV (2 + ) and 14.0 MeV of the 6 He nucleus in the 7 Li( 6 Li, 7 Be) 6 He reaction, have been analyzed in the framework of the finite-range distorted-waves method assuming the 1p- and 1s-proton pick-up mechanism. It has been shown that ( 6 Li, 7 Be) and ( 6 Li, 7 Li) reactions predominately proceed by one-step pick-up mechanism and broad structures which are observed at high excitation energies should be considered as quasimolecular states of the t( 3 He) + d and t( 3 He) + t type [ru

The Interstellar 7Li/6Li Ratio in the Diffuse Gas Near IC 443

Science.gov (United States)

Ritchey, A. M.; Taylor, C. J.; Federman, S. R.; Lambert, D. L.

2010-11-01

Supernova remnants are believed to be the primary acceleration sites of Galactic cosmic rays (GCR), which are essential to gas-phase interstellar chemistry since they are a major source of ionization in both diffuse and dense environments. The interaction of accelerated particles with interstellar gas will also synthesize isotopes of the light elements Li, Be, and B through the spallation of CNO nuclei (producing all stable LiBeB isotopes) and through α+α fusion (yielding 6Li and 7Li, only). Type II supernovae may provide an additional source of 7Li and 11B during core collapse through neutrino-induced spallation in the He and C shells of the progenitor star (the ν-process). However, direct observational evidence for light element synthesis resulting from cosmic-ray or neutrino-induced spallation is rare. Here, we examine 7Li/6Li isotope ratios along four lines of sight through the supernova remnant IC 443 using observations of the Li I λ6707 doublet made with the Hobby-Eberly Telescope (HET) at McDonald Observatory. The 7Li/6Li ratio in the general interstellar medium is expected to be similar to the ratio of ~12 that characterizes solar system material. A local enhancement in the cosmic-ray flux will act to lower 7Li/6Li, yielding a ratio of ~2 when cosmic rays dominate Li synthesis. Gamma-ray emission from IC 443 provides strong evidence for the interaction of cosmic rays accelerated by the remnant with the ambient atomic and molecular gas. Yet this material has also been contaminated by the ejecta of a Type II supernova, which should be enriched in 7Li. We are seeking 7Li/6Li ratios that are either higher than the solar system ratio as a result of the ν-process or lower due to cosmic-ray spallation. Since the fine structure separation of the Li I doublet is comparable to the isotope shift (~7 km s-1) and each fine structure line is further split into hyperfine components, the velocity structure along the line of sight must be carefully constrained if

The preparation and role of Li_2ZrO_3 surface coating LiNi_0_._5Co_0_._2Mn_0_._3O_2 as cathode for lithium-ion batteries

International Nuclear Information System (INIS)

Xu, Yue; Liu, Yang; Lu, Zhongpei; Wang, Haiying; Sun, Deqin; Yang, Gang

2016-01-01

Graphical abstract: LiNi_0_._5Co_0_._2Mn_0_._3O_2 is coated by Li_2ZrO_3 layer with the thickness about 20 nm. Li_2ZrO_3 coating effectively improves cycling performance and rate capability. LZO-LMO delivers 194 mAh g"−"1 at 0.2 C and presents improved cyclic performance at 55 °C. - Highlights: • LiNi_0_._5Co_0_._2Mn_0_._3O_2 is coated by Li_2ZrO_3 layer with the thickness about 20 nm. • Li_2ZrO_3 coating effectively improves cycling performance and rate capability. • LZO-LMO delivers 194 mAh g"−"1 at 0.2 C and presents improved cyclic performance at 55 °C. • Li_2ZrO_3 coating suppresses cation dissolution and enhances the structural stability. - Abstract: Li_2ZrO_3-coated LiNi_0_._5Co_0_._2Mn_0_._3O_2 (LZO-LMO) is successful synthesized by using a wet chemical method. Li_2ZrO_3 coating formed a uniform layer on LiNi_0_._5Co_0_._2Mn_0_._3O_2 particles (LMO) without changing the crystal structure. Cyclic voltammetry (CV) and charge–discharge tests show that the Li_2ZrO_3-modified layer can improve the cyclic and rate performance. In the cut-off voltage of 2.7–4.6 V, LZO-LMO maintains 86% of the initial capacity at the 50th cycle, which is much higher than LMO with the retention of 66% of the initial capacity. The coating layer of LZO plays the positive role in conductivity of lithium diffusion and improves rate performance of LMO. At 10 C rates, LZO-LMO delivers the initial capacity of 95 mAh g"−"1 which is much higher than 40 mAh g"−"1 delivered by LMO. At the environmental temperature of 55 °C, LZO-LMO delivers the initial capacity of 194 mAh g"−"1 at 0.2 C rate and presents an improved cyclic performance in comparison with LMO. The elemental analysis of electrodes carried out after 50 charge/discharge cycles shows minor Ni content deviation in LMO, but LZO-LMO still remains the stoichiometric ratio, because the Li_2ZrO_3 coating efficiently hinders the metal dissolution during charge/discharge.

Understanding LiOH chemistry in a ruthenium-catalyzed Li-O{sub 2} battery

Energy Technology Data Exchange (ETDEWEB)

Liu, Tao; Liu, Zigeng; Kim, Gunwoo; Grey, Clare P. [Department of Chemistry, University of Cambridge (United Kingdom); Frith, James T.; Garcia-Araez, Nuria [Department of Chemistry, University of Southampton (United Kingdom)

2017-12-11

Non-aqueous Li-O{sub 2} batteries are promising for next-generation energy storage. New battery chemistries based on LiOH, rather than Li{sub 2}O{sub 2}, have been recently reported in systems with added water, one using a soluble additive LiI and the other using solid Ru catalysts. Here, the focus is on the mechanism of Ru-catalyzed LiOH chemistry. Using nuclear magnetic resonance, operando electrochemical pressure measurements, and mass spectrometry, it is shown that on discharging LiOH forms via a 4 e{sup -} oxygen reduction reaction, the H in LiOH coming solely from added H{sub 2}O and the O from both O{sub 2} and H{sub 2}O. On charging, quantitative LiOH oxidation occurs at 3.1 V, with O being trapped in a form of dimethyl sulfone in the electrolyte. Compared to Li{sub 2}O{sub 2}, LiOH formation over Ru incurs few side reactions, a critical advantage for developing a long-lived battery. An optimized metal-catalyst-electrolyte couple needs to be sought that aids LiOH oxidation and is stable towards attack by hydroxyl radicals. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Modeling Li-ion conductivity in LiLa(PO3)4 powder

International Nuclear Information System (INIS)

Mounir, Ferhi; Karima, Horchani-Naifer; Khaled, Ben Saad; Mokhtar, Férid

2012-01-01

Polycrystalline powder and single-crystal of LiLa(PO 3 ) 4 are synthesized by solid state reaction and flux technique, respectively. A morphological description of the obtained product was made based on scanning electron microscopy micrographs. The obtained powder was characterized by X-ray powder diffraction, FTIR and Raman spectroscopies. Ionic conductivity of the LiLa(PO 3 ) 4 powder was measured and evaluated over a temperature range from 553 to 913 K. Single crystals of LiLa(PO 3 ) 4 are characterized by single-crystal X-ray diffraction. The LiLa(PO 3 ) 4 structure was found to be isotypic with LiNd(PO 3 ) 4 . It crystallizes in the monoclinic system with space group C2/c and cell parameters: a=16.635(6) Å, b=7.130(3) Å, c=9.913(3) Å, β=126.37(4)°, V=946.72(6) Å 3 and Z=4. The LiLa(PO 3 ) 4 structure was described as an alternation between spiraling chains (PO 3 ) n and (La 3+ , Li + ) cations along the b direction. The small Li + ions, coordinated to four oxygen atoms, were located in the large connected cavities created between the LaO 8 polyhedra and the polyphosphate chains. The jumping of Li + through tunnels of the crystalline network was investigated using complex impedance spectroscopy. The close value of the activation energies calculated through the analysis of conductivity data and loss spectra indicate that the transport in the investigated system is through hopping mechanism. The correlation between ionic conductivity of LiLa(PO 3 ) 4 and its crystallographic structure was investigated and the most probably transport pathway model was determined.

Li-ion conduction in the LiBH4:LiI system from Density Functional Theory calculations and Quasi-Elastic Neutron Scattering

DEFF Research Database (Denmark)

Myrdal, Jon Steinar Gardarsson; Blanchard, Didier; Sveinbjörnsson, Dadi Þorsteinn

2013-01-01

The hexagonal high-temperature polymorph of LiBH4 is stabilized by solid solution with LiI to exhibit superionic Li+ ionic conductivity at room temperature. Herein, the mechanisms for the Li+ diffusion are investigated for the first time by density functional theory (DFT) calculations coupled...

Silver-coated LiVPO4F composite with improved electrochemical performance as cathode material for lithium-ion batteries

Science.gov (United States)

Yang, Bo; Yang, Lin

2015-12-01

Nano-structured LiVPO4F/Ag composite cathode material has been successfully synthesized via a sol-gel route. The structural and physical properties, as well as the electrochemical performance of the material are compared with those of the pristine LiVPO4F. X-ray diffraction (XRD) and scanning electron microscopy (SEM) reveal that Ag particles are uniformly dispersed on the surface of LiVPO4F without destroying the crystal structure of the bulk material. An analysis of the electrochemical measurements show that the Ag-modified LiVPO4F material exhibits high discharge capacity, good cycle performance (108.5 mAh g-1 after 50th cycles at 0.1 C, 93% of initial discharge capacity) and excellent rate behavior (81.8 mAh g-1 for initial discharge capacity at 5 C). The electrochemical impedance spectroscopy (EIS) results reveal that the adding of Ag decreases the charge-transfer resistance (Rct) of LiVPO4F cathode. This study demonstrates that Ag-coating is a promising way to improve the electrochemical performance of the pristine LiVPO4F for lithium-ion batteries cathode material.

Retrieving aboveground biomass of wetland Phragmites australis (common reed) using a combination of airborne discrete-return LiDAR and hyperspectral data

Science.gov (United States)

Luo, Shezhou; Wang, Cheng; Xi, Xiaohuan; Pan, Feifei; Qian, Mingjie; Peng, Dailiang; Nie, Sheng; Qin, Haiming; Lin, Yi

2017-06-01

Wetland biomass is essential for monitoring the stability and productivity of wetland ecosystems. Conventional field methods to measure or estimate wetland biomass are accurate and reliable, but expensive, time consuming and labor intensive. This research explored the potential for estimating wetland reed biomass using a combination of airborne discrete-return Light Detection and Ranging (LiDAR) and hyperspectral data. To derive the optimal predictor variables of reed biomass, a range of LiDAR and hyperspectral metrics at different spatial scales were regressed against the field-observed biomasses. The results showed that the LiDAR-derived H_p99 (99th percentile of the LiDAR height) and hyperspectral-calculated modified soil-adjusted vegetation index (MSAVI) were the best metrics for estimating reed biomass using the single regression model. Although the LiDAR data yielded a higher estimation accuracy compared to the hyperspectral data, the combination of LiDAR and hyperspectral data produced a more accurate prediction model for reed biomass (R2 = 0.648, RMSE = 167.546 g/m2, RMSEr = 20.71%) than LiDAR data alone. Thus, combining LiDAR data with hyperspectral data has a great potential for improving the accuracy of aboveground biomass estimation.

A novel dual-salts of LiTFSI and LiODFB in LiFePO4-based batteries for suppressing aluminum corrosion and improving cycling stability

Science.gov (United States)

Li, Faqiang; Gong, Yan; Jia, Guofeng; Wang, Qinglei; Peng, Zhengjun; Fan, Wei; Bai, Bing

2015-11-01

The strong corrosion behavior at the Al current collector restricts the application range of lithium bis (trifluoromethanesulfonylimide) (LiTFSI), despite its high stability against water and thermal. SEM, LSV and Tafel curves proved that adding LiODFB into LiTFSI-based electrolytes could suppress aluminum corrosion caused by LiTFSI-based electrolytes. The cycling stability and rate capability of LiFePO4-based batteries using LiTFSI0.6-LiODFB0.4-based electrolytes is excellent as compared to LiFePO4-based batteries using LiPF6-based electrolytes.

Thermoluminescence of LiF: Mg, Ti between 77 and 315 K

International Nuclear Information System (INIS)

Rosa, L.A.R. da.

1989-01-01

A special thermoluminescent system was developed. It is able to operate right from liquid nitrogen temperature and also permits the determination of the sample thermoluminescent emission spectrum. Using this system, the thermoluminescence displayed by 77 K irradiated LiF:Mg,Ti (TLD-100), from the irradiation temperature to 315 K, was studied. In this temperature range seven glow peaks, at 139, 153, 194, 240, 260, 283 and 300 K, were determined. (author)

77 FR 32021 - Safety Zones: Fireworks Displays in the Captain of the Port Columbia River Zone

Science.gov (United States)

2012-05-31

...:30 p.m. (2) Tri-City Chamber of Commerce Fireworks Display, Columbia Park, Kennewick, WA: July 4...) Arlington Chamber of Commerce Fireworks Display, Arlington, OR: July 4, 2012 from 8:30 p.m. until 11:30 p.m..., 2012 from 8:30 p.m. until 11:30 p.m. (7) Florence Chamber 4th of July Fireworks Display, Florence, OR...

G-LiHT: Goddard's LiDAR, Hyperspectral and Thermal Airborne Imager

Science.gov (United States)

Cook, Bruce; Corp, Lawrence; Nelson, Ross; Morton, Douglas; Ranson, Kenneth J.; Masek, Jeffrey; Middleton, Elizabeth

2012-01-01

Scientists at NASA's Goddard Space Flight Center have developed an ultra-portable, low-cost, multi-sensor remote sensing system for studying the form and function of terrestrial ecosystems. G-LiHT integrates two LIDARs, a 905 nanometer single beam profiler and 1550 nm scanner, with a narrowband (1.5 nanometers) VNIR imaging spectrometer and a broadband (8-14 micrometers) thermal imager. The small footprint (approximately 12 centimeters) LIDAR data and approximately 1 meter ground resolution imagery are advantageous for high resolution applications such as the delineation of canopy crowns, characterization of canopy gaps, and the identification of sparse, low-stature vegetation, which is difficult to detect from space-based instruments and large-footprint LiDAR. The hyperspectral and thermal imagery can be used to characterize species composition, variations in biophysical variables (e.g., photosynthetic pigments), surface temperature, and responses to environmental stressors (e.g., heat, moisture loss). Additionally, the combination of LIDAR optical, and thermal data from G-LiHT is being used to assess forest health by sensing differences in foliage density, photosynthetic pigments, and transpiration. Low operating costs (approximately $1 ha) have allowed us to evaluate seasonal differences in LiDAR, passive optical and thermal data, which provides insight into year-round observations from space. Canopy characteristics and tree allometry (e.g., crown height:width, canopy:ground reflectance) derived from G-LiHT data are being used to generate realistic scenes for radiative transfer models, which in turn are being used to improve instrument design and ensure continuity between LiDAR instruments. G-LiHT has been installed and tested in aircraft with fuselage viewports and in a custom wing-mounted pod that allows G-LiHT to be flown on any Cessna 206, a common aircraft in use throughout the world. G-LiHT is currently being used for forest biomass and growth estimation

Enhanced Lithium Ion Transport by Superionic Pathways Formed on the Surface of Two-dimensional Structured Li0.85Na0.15V3O8 for High-Performance Lithium Ion Batteries

International Nuclear Information System (INIS)

Lu, Xuena; Shang, Yu; Zhang, Sen; Deng, Chao

2015-01-01

Highlights: • Li 0.85 Na 0.15 V 3 O 8 nanosheet with superionic conductive layer was constructed. • Li x V 2 O 5 surface layer provides facile pathways for lithium migration. • Li x V 2 O 5 -Li 0.85 Na 0.15 V 3 O 8 composite displays good high rate capability. - Abstract: Poor ion transport and rate capability are the main challenges for LiV 3 O 8 as cathode material for lithium ion batteries. Here we report a novel strategy for enhancing lithium ion transport by building superionic pathways on the surface of Li 0.85 Na 0.15 V 3 O 8 nanosheet. The two-dimensional Li 0.85 Na 0.15 V 3 O 8 nanoparticle with an ion conductive layer of Li x V 2 O 5 on its surface is constructed by a modified sol–gel strategy with carefully controlled sodium incorporation and elements stoichiometry. Ultrathin Li x V 2 O 5 surface layer not only provides facile pathways for lithium migration, but also increases the structure stability during cycling. The Li x V 2 O 5 -Li 0.85 Na 0.15 V 3 O 8 composite displays good high rate capability of 172.3 mAh g −1 at 5C and excellent cycling stability of 98.9% over fifty cycles. This superior electrochemical property is attributed to the occupation of lithium site by Na + in LiV 3 O 8 host crystals and the surface superionic pathways of Li x V 2 O 5 phase. Therefore, the advantages of both high ion transport and the structure stabilization in present study put forward a new strategy for achieving high-performance LiV 3 O 8 electrode material with tailored nanoarchitecture

The different Li/Na ion storage mechanisms of nano Sb2O3 anchored on graphene

Science.gov (United States)

Li, Hai; Qian, Kun; Qin, Xianying; Liu, Dongqing; Shi, Ruiying; Ran, Aihua; Han, Cuiping; He, Yan-Bing; Kang, Feiyu; Li, Baohua

2018-05-01

The antimony oxide/reduced graphene oxide (Sb2O3/rGO) nanocomposites are used as anode of Li-ion and Na-ion batteries (LIBs and NIBs). However, it is unclear about Li-ion and Na-ion storage mechanism in Sb2O3/rGO nanocomposites. Herein, the conversion-alloying mechanisms of Sb2O3/rGO anodes for Na-ion and Li-ion storage are comparatively studied with a combined in-situ XRD and quasi in-situ XPS method. The distinct behaviours are monitored during (de)lithiation and (de)sodiation with respect to crystal structure and chemical composition evolution. It is evidenced that the Na-ion can be easily transported to the inner part of the Sb2O3, where the Li-ion almost cannot reach, leading to a fully transformation during sodiation. In addition, the conversion reaction product of amorphous Na2O display their better chemical stability than amorphous Li2O during electrochemical cycles, which contribute to a stable and long cycling life of NIBs. This work gain insight into the high-capacity anodes with conversation-alloying mechanism for NIBs.

Energetics of a Li Atom adsorbed on B/N doped graphene with monovacancy

International Nuclear Information System (INIS)

Rani, Babita; Jindal, V.K.; Dharamvir, Keya

2016-01-01

We use density functional theory (DFT) to study the adsorption properties and diffusion of Li atom across B/N-pyridinic graphene. Regardless of the dopant type, B atoms of B-pyridinic graphene lose electron density. On the other hand, N atoms (p-type dopants) have tendency to gain electron density in N-pyridinic graphene. Higher chemical reactivity and electronic conductivity of B/N-pyridinic graphene are responsible for stronger binding of Li with the substrates as compared to pristine graphene. The binding energy of Li with B/N-pyridinic graphene exceeds the cohesive energy of bulk Li, making it energetically unfavourable for Li to form clusters on these substrates. Li atom gets better adsorbed on N-pyridinic graphene due to an additional p-p hybridization of the orbitals while Li on B-pyridinic prefers the ionic bonding. Also, significant distortion of N-pyridinic graphene upon Li adsorption is a consequence of the change in bonding mechanism between Li atom and the substrate. Our results show that bonding character and hence binding energies between Li and graphene can be tuned with the help of B/N doping of monovacancy defects. Further, the sites for most stable adsorption are different for the two types of doped and defective graphene, leading to greater Li uptake capacity of B-pyridinic graphene near the defect. In addition, B-pyridinic graphene offering lower diffusion barrier, ensures better Li kinetics. Thus, B-pyridinic graphene presents itself as a better anode material for LIBs as compared to N-pyridinic graphene. - Graphical abstract: Adsorption and diffusion of Li atom across the B/N doped monovacancy graphene is studied using ab-initio DFT calculations. Our results show that bonding mechanism and binding of Li with graphene can be tuned with the help of N/B doping of defects. Also, B-pyridinic graphene presents itself as a better anode material for lithium ion batteries as compared to N-pyridinic graphene. Display Omitted - Highlights: • Density

Energetics of a Li Atom adsorbed on B/N doped graphene with monovacancy

Energy Technology Data Exchange (ETDEWEB)

Rani, Babita, E-mail: babitabaghla15@gmail.com [Department of Physics, Panjab University, Chandigarh 160014 (India); Department of Physics, Punjabi University, Patiala 147002 (India); Jindal, V.K. [Department of Physics, Panjab University, Chandigarh 160014 (India); Dharamvir, Keya, E-mail: keya@pu.ac.in [Department of Physics, Panjab University, Chandigarh 160014 (India)

2016-08-15

We use density functional theory (DFT) to study the adsorption properties and diffusion of Li atom across B/N-pyridinic graphene. Regardless of the dopant type, B atoms of B-pyridinic graphene lose electron density. On the other hand, N atoms (p-type dopants) have tendency to gain electron density in N-pyridinic graphene. Higher chemical reactivity and electronic conductivity of B/N-pyridinic graphene are responsible for stronger binding of Li with the substrates as compared to pristine graphene. The binding energy of Li with B/N-pyridinic graphene exceeds the cohesive energy of bulk Li, making it energetically unfavourable for Li to form clusters on these substrates. Li atom gets better adsorbed on N-pyridinic graphene due to an additional p-p hybridization of the orbitals while Li on B-pyridinic prefers the ionic bonding. Also, significant distortion of N-pyridinic graphene upon Li adsorption is a consequence of the change in bonding mechanism between Li atom and the substrate. Our results show that bonding character and hence binding energies between Li and graphene can be tuned with the help of B/N doping of monovacancy defects. Further, the sites for most stable adsorption are different for the two types of doped and defective graphene, leading to greater Li uptake capacity of B-pyridinic graphene near the defect. In addition, B-pyridinic graphene offering lower diffusion barrier, ensures better Li kinetics. Thus, B-pyridinic graphene presents itself as a better anode material for LIBs as compared to N-pyridinic graphene. - Graphical abstract: Adsorption and diffusion of Li atom across the B/N doped monovacancy graphene is studied using ab-initio DFT calculations. Our results show that bonding mechanism and binding of Li with graphene can be tuned with the help of N/B doping of defects. Also, B-pyridinic graphene presents itself as a better anode material for lithium ion batteries as compared to N-pyridinic graphene. Display Omitted - Highlights: • Density

Electrochemical performances of LiMnPO4 synthesized from non-stoichiometric Li/Mn ratio.

Science.gov (United States)

Xiao, Jie; Chernova, Natasha A; Upreti, Shailesh; Chen, Xilin; Li, Zheng; Deng, Zhiqun; Choi, Daiwon; Xu, Wu; Nie, Zimin; Graff, Gordon L; Liu, Jun; Whittingham, M Stanley; Zhang, Ji-Guang

2011-10-28

In this paper, the influences of the lithium content in the starting materials on the final performances of as-prepared Li(x)MnPO(4) (x hereafter represents the starting Li content in the synthesis step which does not necessarily mean that Li(x)MnPO(4) is a single phase solid solution in this work.) are systematically investigated. It has been revealed that Mn(2)P(2)O(7) is the main impurity when Li Li(3)PO(4) begins to form once x > 1.0. The interactions between Mn(2)P(2)O(7) or Li(3)PO(4) impurities and LiMnPO(4) are studied in terms of the structural, electrochemical, and magnetic properties. At a slow rate of C/50, the reversible capacity of both Li(0.5)MnPO(4) and Li(0.8)MnPO(4) increases with cycling. This indicates a gradual activation of more sites to accommodate a reversible diffusion of Li(+) ions that may be related to the interaction between Mn(2)P(2)O(7) and LiMnPO(4) nanoparticles. Among all of the different compositions, Li(1.1)MnPO(4) exhibits the most stable cycling ability probably because of the existence of a trace amount of Li(3)PO(4) impurity that functions as a solid-state electrolyte on the surface. The magnetic properties and X-ray absorption spectroscopy (XAS) of the MnPO(4)·H(2)O precursor, pure and carbon-coated Li(x)MnPO(4) are also investigated to identify the key steps involved in preparing a high-performance LiMnPO(4). This journal is © the Owner Societies 2011

Li-rich anti-perovskite Li3OCl films with enhanced ionic conductivity

Energy Technology Data Exchange (ETDEWEB)

Lu, XJ; Wu, G; Howard, JW; Chen, AP; Zhao, YS; Daemen, LL; Jia, QX

2014-08-13

Anti-perovskite solid electrolyte films were prepared by pulsed laser deposition, and their room-temperature ionic conductivity can be improved by more than an order of magnitude in comparison with its bulk counterpart. The cyclability of Li3OCl films in contact with lithium was evaluated using a Li/Li3OCl/Li symmetric cell, showing self-stabilization during cycling test.

Li plating as unwanted side reaction in commercial Li-ion cells - A review

Science.gov (United States)

Waldmann, Thomas; Hogg, Björn-Ingo; Wohlfahrt-Mehrens, Margret

2018-04-01

Deposition of Lithium metal on anodes contributes significantly to ageing of Li-ion cells. Lithium deposition is connected not only to a drastic limitation of life-time, but also to fast-charging capability and safety issues. Lithium deposition in commercial Li-ion cells is not limited to operation conditions at low temperatures. In recent publications various types of commercial cells were investigated using complimentary analysis methods. Five cell types studied in literature (18650, 26650, pouch) serve as a basis for comparison when and why Li deposition happens in commercial Li-ion cells. In the present paper, we reviewed literature on (i) causes, (ii) hints and evidences for Li deposition, (iii) macroscopic morphology of Li deposition/plating, (iv) ageing mechanisms and shapes of capacity fade curves involving Li deposition, and (v) influences of Li deposition on safety. Although often discussed, safety issues regarding Li deposition are not only limited to dendrite growth and internal short circuits, but also to exothermic reactions in the presence of Lithium metal. Furthermore, we tried to connect knowledge from different length scales including the macroscopic level (Li-ion cells, operating conditions, gradients in cells, electrochemical tests, safety tests), the microscopic level (electrodes, particles, microstructure), and the atomic level (atoms, ions, molecules, energy barriers).

Atomic simulations for configurations and solid-liquid interface of Li-Fe and Li-Cu icosahedra

Energy Technology Data Exchange (ETDEWEB)

Yang, Jianyu, E-mail: hnieyjy@aliyun.com [Hunan Institute of Engineering (China); Hu, Wangyu [Hunan University, College of Materials Science and Engineering (China); Dai, Xiongying [Hunan Institute of Engineering, College of Science (China)

2017-04-15

The melting point of Li is lower than that of Fe (or Cu); thus, solid-liquid interfaces can be easily formed on Li-Fe and Li-Cu nanoalloys. In this work, the configurations and solid-liquid interfaces of Li-Fe and Li-Cu icosahedra are studied using Monte Carlo and molecular dynamics methods. The atomic interactions are described by the analytic embedded-atom method. The dependence of composition, temperature, and nanoparticle size on the configurations and thermal stabilities of nanoalloys is discussed. The behavior of the Li-Fe and Li-Cu nanoalloys in segregation, configuration, and thermal stability is investigated. A different behavior of surface segregation of Li atoms is observed for the two types of nanoalloys. The interface between the Li and Fe atoms is clear. Mixing of Li with Cu at larger nanoparticle sizes is found because of low heat of formation in the system. The configurations of the Li-Fe and Li-Cu nanoalloys are related to the competition between surface segregation and alloying. The thermal stability of Li in the two types of nanoalloys is enhanced by the support of the Fe (or Cu) solid substrate.

Sum rule for bremsstrahlung cross section for 6Li in the resonating-group method

International Nuclear Information System (INIS)

Lodhi, M.A.K.; Wood, K.E.

1982-01-01

In the method of resonating-group structure, the wave function of 6 Li is assumed to have a single channel of alpha and deuteron substructures in the ground state. It is shown that the intercluster exchange of nucleons is an important effect which causes significant change in the root mean square radius and the dipole transition cross section. Due to lack of symmetry in space coordinates of 6 Li, the dipole operator is not identical to the mean square operator for this sum rule calculation and is expected to display like behavior in similar systems. It is also shown that the deuteron substructure in this nucleus is substantially larger than the alpha substructure. (orig.)

Extreme UV and X-ray scattering measurements from a rough LiF crystal surface characterized by electron micrography

DEFF Research Database (Denmark)

Alehyane; Arbaoui; Barchewitz

1989-01-01

XUV and X-ray scattering by a LiF crystal is measured. The angular distribution of the scattered radiation (ADSR) reveals characteristic features, side peaks or asymmetry. The surface of the sample is statistically characterized by a microdensitometer analysis of electron micrographs resolving th...

Spectroscopic analysis of LiHoF4 and LiErF4

DEFF Research Database (Denmark)

Christensen, H.P.

1979-01-01

The polarized absorption spectra for Ho3+ and Er3+ in LiHoF4 and LiErF4, respectively, have been recorded in the spectral interval 4000-26 000 cm-1 at 2 K. Parts of the spectra were examined at higher temperatures. The experimental levels for Ho3+ and Er3+ in LiRF4 were close to those found in Li...

Mechanistic insights of Li+ diffusion within doped LiFePO4 from Muon Spectroscopy.

Science.gov (United States)

Johnson, Ian D; Ashton, Thomas E; Blagovidova, Ekaterina; Smales, Glen J; Lübke, Mechthild; Baker, Peter J; Corr, Serena A; Darr, Jawwad A

2018-03-07

The Li + ion diffusion characteristics of V- and Nb-doped LiFePO 4 were examined with respect to undoped LiFePO 4 using muon spectroscopy (µSR) as a local probe. As little difference in diffusion coefficient between the pure and doped samples was observed, offering D Li values in the range 1.8-2.3 × 10 -10  cm 2 s -1 , this implied the improvement in electrochemical performance observed within doped LiFePO 4 was not a result of increased local Li + diffusion. This unexpected observation was made possible with the µSR technique, which can measure Li + self-diffusion within LiFePO 4 , and therefore negated the effect of the LiFePO 4 two-phase delithiation mechanism, which has previously prevented accurate Li + diffusion comparison between the doped and undoped materials. Therefore, the authors suggest that µSR is an excellent technique for analysing materials on a local scale to elucidate the effects of dopants on solid-state diffusion behaviour.

Uniform second Li ion intercalation in solid state ϵ-LiVOPO{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Wangoh, Linda W.; Quackenbush, Nicholas F. [Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, New York 13902 (United States); Sallis, Shawn [Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States); Wiaderek, Kamila M.; Ma, Lu; Wu, Tianpin; Chapman, Karena W. [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Lin, Yuh-Chieh; Ong, Shyue Ping [Department of NanoEngineering, University of California San Diego, 9500 Gilman Drive 0448, La Jolla, California 92093 (United States); Wen, Bohua; Chernova, Natasha A.; Whittingham, M. Stanley [NECCES, Binghamton University, Binghamton, New York 13902 (United States); Guo, Jinghua [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Lee, Tien-Lin; Schlueter, Christoph [Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Piper, Louis F. J., E-mail: lpiper@binghamton.edu [Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, New York 13902 (United States); Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States)

2016-08-01

Full, reversible intercalation of two Li{sup +} has not yet been achieved in promising VOPO{sub 4} electrodes. A pronounced Li{sup +} gradient has been reported in the low voltage window (i.e., second lithium reaction) that is thought to originate from disrupted kinetics in the high voltage regime (i.e., first lithium reaction). Here, we employ a combination of hard and soft x–ray photoelectron and absorption spectroscopy techniques to depth profile solid state synthesized LiVOPO{sub 4} cycled within the low voltage window only. Analysis of the vanadium environment revealed no evidence of a Li{sup +} gradient, which combined with almost full theoretical capacity confirms that disrupted kinetics in the high voltage window are responsible for hindering full two lithium insertion. Furthermore, we argue that the uniform Li{sup +} intercalation is a prerequisite for the formation of intermediate phases Li{sub 1.50}VOPO{sub 4} and Li{sub 1.75}VOPO{sub 4}. The evolution from LiVOPO{sub 4} to Li{sub 2}VOPO{sub 4} via the intermediate phases is confirmed by direct comparison between O K–edge absorption spectroscopy and density functional theory.

Ab initio identification of the Li-rich phase in LiFePO4.

Science.gov (United States)

Zeng, Hua; Gu, Yue; Teng, Gaofeng; Liu, Yimeng; Zheng, Jiaxin; Pan, Feng

2018-06-27

A recent discovery of anionic redox activity in Li-rich layered compounds opens a new direction for the design of high-capacity cathode materials for lithium-ion batteries. Here using extensive ab initio calculations, the thermodynamic existence of the Li-rich phase in LiFePO4 to form Li1+xFe1-xPO4 with x not exceeding 12.5% has been proved. Anionic redox activity and structural stability during delithiation are further investigated. Interestingly, it is found that Li1+xFe1-xPO4 cannot be delithiated completely and thus cannot achieve extra capacity by anionic redox activity, because the local oxygen-ion redox will cause the fracture of the rigid framework formed by phosphate tetrahedral polyanions. Although an extra capacity cannot be realized, the excess Li-ions at Fe sites can enhance the Li-ion diffusivity along the adjacent [010] channel and contribute to the shift from 1D to 2D/3D diffusion. This study provides a fresh perspective on olivine-type LiFePO4 and offers some important clues on designing Li-rich cathode materials with high energy density.

Re-building Daniell Cell with a Li-ion exchange Film

OpenAIRE

Dong, Xiaoli; Wang, Yonggang; Xia, Yongyao

2014-01-01

Daniell cell (i.e. Zn-Cu battery) is widely used in chemistry curricula to illustrate how batteries work, although it has been supplanted in the late 19th century by more modern battery designs because of Cu2+-crossover-induced self-discharge and un-rechargeable characteristic. Herein, it is re-built by using a ceramic Li-ion exchange film to separate Cu and Zn electrodes for preventing Cu2+-crossover between two electrodes. The re-built Zn-Cu battery can be cycled for 150 times without capac...

Li vaporization property of two-phase material of Li{sub 2}TiO{sub 3} and Li{sub 2}SiO{sub 3} for tritium breeder

Energy Technology Data Exchange (ETDEWEB)

Ogawa, Seiya [Course of Mechanical Engineering, Graduate School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Masuko, Yuki; Kato, Hirokazu; Yuyama, Hayato; Sakai, Yutaro [Department of Prime Mover Engineering, School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Niwa, Eiki; Hashimoto, Takuya [Department of Physics, College of Humanities and Sciences, Nihon University, 3-8-1 Sakurajousui, Setagaya-ku, Tokyo 156-8550 (Japan); Mukai, Keisuke [Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, 7-3-1 Bunkyo-ku, Tokyo 113-8656 (Japan); Hosino, Tsuyoshi [Breeding Functional Materials Development Group, Department of Blanket Systems Research, Rokkasho Fusion Institute, Sector of Fusion Research and Development, Japan Atomic Energy Agency, 2-166 Obuch, Omotedate, Rokkasho-mura, Kamikita-gun, Aomori 039-3212 (Japan); Sasaki, Kazuya, E-mail: k_sasaki@tokai-u.jp [Course of Mechanical Engineering, Graduate School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Department of Prime Mover Engineering, School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); Course of Mechanical Engineering and Aeronautics and Astronautics, Graduate School of Science and Technology, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan)

2015-10-15

Highlights: • We synthesized two phase materials based on Li{sub 2}SiO{sub 3} and Li{sub 2}TiO{sub 3}. • We investigated the Li vaporization property of the two-phase materials. • Li vaporization occurs significantly from only Li{sub 2}SiO{sub 3} grains in the vicinity of the surface of the pellets. • The Li vaporization is remarkable only for an early short time for the vaporization from Li{sub 2}SiO{sub 3} grains at the vicinity of the surface. • The second stable phase added functions effectively for inhibition of the Li vaporization. - Abstract: Li vaporization property of two-phase materials of Li{sub 2}TiO{sub 3} and Li{sub 2}SiO{sub 3} in a working condition for the solid tritium breeder used in the demonstration power plant of fusion reactor was investigated, and the suppression mechanism of the vaporization was considered. The Li vaporization rate from the specimen pellet was measured by gravimetric method, and the change of Li concentration distribution in the pellet was analyzed by time-of-flight secondary ion mass spectrometer. Li was vaporized only from the Li{sub 2}SiO{sub 3} at the vicinity of the surface of the pellet. The remarkable vaporization of Li arose only in an early short time. The inhibition of the vaporization from the Li{sub 2}SiO{sub 3} was successful by adding the small amount of the stable secondary phase of Li{sub 2}TiO{sub 3}.

Li14P2O3N6 and Li7PN4: Computational study of two nitrogen rich crystalline LiPON electrolyte materials

Science.gov (United States)

Al-Qawasmeh, Ahmad; Holzwarth, N. A. W.

2017-10-01

Two lithium oxonitridophosphate materials are computationally examined and found to be promising solid electrolytes for possible use in all solid-state batteries having metallic Li anodes - Li14P2O3N6 and Li7PN4. The first principles simulations are in good agreement with the structural analyses reported in the literature for these materials and the computed total energies indicate that both materials are stable with respect to decomposition into binary and ternary products. The computational results suggest that both materials are likely to form metastable interfaces with Li metal. The simulations also find both materials to have Li ion migration activation energies comparable or smaller than those of related Li ion electrolyte materials. Specifically, for Li7PN4, the experimentally measured activation energy can be explained by the migration of a Li ion vacancy stabilized by a small number of O2- ions substituting for N3- ions. For Li14P2O3N6, the activation energy for Li ion migration has not yet been experimentally measured, but simulations predict it to be smaller than that measured for Li7PN4.

Annihilation of antiferromagnetic order in LiCoO2 by excess Li

International Nuclear Information System (INIS)

Sugiyama, Jun; Ikedo, Yutaka; Nozaki, Hiroshi; Mukai, Kazuhiko; Andreica, Daniel; Amato, Alex; Menetrier, Michel; Carlier, Dany; Delmas, Claude

2009-01-01

In order to elucidate the origin of antiferromagnetic (AF) order below 30 K in LiCoO 2 , in which all the Co 3+ ions are in a low-spin state with S=0, the magnetic nature of the Li-excess sample Li 1.04 Co 0.96 O 1.96 was studied by muon-spin spectroscopy in the temperature range between 1.8 and 100 K. Although disordered localized moments appeared below 25 K, static AF order was not detected even at 1.8 K. Moreover, a small amount of excess Li ions (4%) and oxygen vacancies (2%) was found to change ∼50% of the sample into a magnetically disordered phase at 1.8 K. The stoichiometric LiCoO 2 , which was prepared from the same starting materials to those for the Li-excess sample, showed an AF transition at 30 K, while the volume fraction of the AF phase was 10% even at 1.8 K. This therefore excludes the possible role of the excess Li + on the formation of static AF order.

LiFePO4/polymer/natural graphite: low cost Li-ion batteries

International Nuclear Information System (INIS)

Zaghib, K.; Striebel, K.; Guerfi, A.; Shim, J.; Armand, M.; Gauthier, M

2004-01-01

The aging and performance of natural graphite/PEO-based gel electrolyte/LiFePO 4 cells are reported. The gel polymer electrolytes were produced by electron-beam irradiation and then soaked in a liquid electrolyte. The natural graphite anode in gel electrolyte containing LiBF4-EC/GBL exhibited high reversible capacity (345 mAh/g) and high coulombic efficiency (91%). The LiFePO 4 cathode in the same gel-polymer exhibited a reversible capacity of 160 mAh/g and 93% coulombic efficiency. Better performance was obtained at high-rate discharge with 6% carbon additive in the cathode, however the graphite anode performance suffers at high rate. The Li-ion gel polymer battery shows a capacity fade of 13% after 180 cycles and has poor performance at low temperature due to low diffusion of the lithium to the graphite in the GBL system. The LiFePO 4 /gel/Li system has an excellent rate capacity. LiFePO 4 cathode material is suitable for HEV application

A New Lamination and doping Concepts for Enhanced Li – S Battery Performance

Energy Technology Data Exchange (ETDEWEB)

Kumta, Prashant N. [Univ. of Pittsburgh, PA (United States); Datta, Moni K. [Univ. of Pittsburgh, PA (United States); Velikokhatnyi, Oleg [Univ. of Pittsburgh, PA (United States); Murugavel Shanthi, Pavithra [Univ. of Pittsburgh, PA (United States); Gattu, Bharat [Univ. of Pittsburgh, PA (United States)

2017-10-01

Lithium ion batteries (LIBs) clearly dominated the area of high-energy storage systems for the past decade with significant research and development activity focused on the development of cathode and anode materials to maximize the specific energy storage, stability, and cycle life of the batteries. However, with the increasing demand in the EV industry for low cost, low weight, and high-energy storage batteries to meet the EV everywhere grand challenge, the current focus of research has shifted towards the development of lithium sulfur batteries (LSB) owing to the high theoretical specific capacity exhibited by sulfur compared to other cathode materials currently available. Li–S battery shows a theoretical capacity of 1675 mAh/g corresponding to the formation of Li2S which makes sulfur a promising electrode to replace the layered transition metal oxides (~150 mAh/g) and LiFePO4 (~170 mAh/g) hitherto deployed in present LIB systems. Moreover, the abundance of sulfur in the earth’s crust makes it a more economical and highly attractive proposition compared to currently existing cathodes. Despite advantages of sulfur, the existing Li-S battery technology display poor cyclability, low coulombic efficiency (CE) and very low cycle life due to the following issues: 1. Polysulfide (PS) dissolution; 2. Sluggish kinetics of PS to Li2S conversion; 3. High PS diffusivity in the electrolyte; 4. Insulating nature or poor conductivity of sulfur/Li2S; 5. Volumetric expansion/contraction of sulfur; 6. Shuttling of PS along with Li+. These issues result in loss of sulfur causing mechanical disintegration, surface passivation of both anode and cathode, thereby decreasing the specific capacity and columbic efficiency (CE). Present generation sulfur cathodes also show low specific storage capacity, very poor charging rates and low loading densities. Research is needed to overcome the issues impeding Li-S battery technology development.

Distillation of LiCl from the LiCl-Li2O molten salt of the electrolytic reduction process

International Nuclear Information System (INIS)

Kim, I.S.; Oh, S.C.; Im, H.S.; Hur, J.M.; Lee, H.S.

2013-01-01

Electrolytic reduction of the uranium oxide in LiCl-Li 2 O molten salt for the treatment of spent nuclear fuel requires the separation of the residual salt from the reduced metal product, which contains about 20 wt% salt. In order to separate the residual salt and reuse it in the electrolytic reduction, a vacuum distillation process was developed. Lab-scale distillation equipment was designed and installed in an argon atmosphere glove box. The equipment consisted of an evaporator in which the reduced metal product was contained and exposed to a high temperature and reduced pressure; a receiver; and a vertically oriented condenser that operated at a temperature below the melting point of lithium chloride. We performed experiments with LiCl-Li 2 O salt to evaluate the evaporation rate of LiCl salt and varied the operating temperature to discern its effect on the behavior of salt evaporation. Complete removal of the LiCl salt from the evaporator was accomplished by reducing the internal pressure to <100 mTorr and heating to 900 deg C. We achieved evaporation efficiency as high as 100 %. (author)

Improving ability measurement in surveys by following the principles of IRT: The Wordsum vocabulary test in the General Social Survey.

Science.gov (United States)

Cor, M Ken; Haertel, Edward; Krosnick, Jon A; Malhotra, Neil

2012-09-01

Survey researchers often administer batteries of questions to measure respondents' abilities, but these batteries are not always designed in keeping with the principles of optimal test construction. This paper illustrates one instance in which following these principles can improve a measurement tool used widely in the social and behavioral sciences: the GSS's vocabulary test called "Wordsum". This ten-item test is composed of very difficult items and very easy items, and item response theory (IRT) suggests that the omission of moderately difficult items is likely to have handicapped Wordsum's effectiveness. Analyses of data from national samples of thousands of American adults show that after adding four moderately difficult items to create a 14-item battery, "Wordsumplus" (1) outperformed the original battery in terms of quality indicators suggested by classical test theory; (2) reduced the standard error of IRT ability estimates in the middle of the latent ability dimension; and (3) exhibited higher concurrent validity. These findings show how to improve Wordsum and suggest that analysts should use a score based on all 14 items instead of using the summary score provided by the GSS, which is based on only the original 10 items. These results also show more generally how surveys measuring abilities (and other constructs) can benefit from careful application of insights from the contemporary educational testing literature. Copyright © 2012 Elsevier Inc. All rights reserved.

Elastic, dynamical, and electronic properties of LiHg and Li3Hg: First-principles study

Science.gov (United States)

Wang, Yan; Hao, Chun-Mei; Huang, Hong-Mei; Li, Yan-Ling

2018-04-01

The elastic, dynamical, and electronic properties of cubic LiHg and Li3Hg were investigated based on first-principles methods. The elastic constants and phonon spectral calculations confirmed the mechanical and dynamical stability of the materials at ambient conditions. The obtained elastic moduli of LiHg are slightly larger than those of Li3Hg. Both LiHg and Li3Hg are ductile materials with strong shear anisotropy as metals with mixed ionic, covalent, and metallic interactions. The calculated Debye temperatures are 223.5 K and 230.6 K for LiHg and Li3Hg, respectively. The calculated phonon frequency of the T2 g mode in Li3Hg is 326.8 cm-1. The p states from the Hg and Li atoms dominate the electronic structure near the Fermi level. These findings may inspire further experimental and theoretical study on the potential technical and engineering applications of similar alkali metal-based intermetallic compounds.

Nano-hydroxyapatite as an Efficient Polysulfide Absorbent for High-performance Li-S Batteries

International Nuclear Information System (INIS)

Liu, Naiqiang; Ai, Fei; Wang, Weikun; Shao, Hongyuan; Zhang, Hao; Wang, Anbang; Xu, Zhichuan J.; Huang, Yaqin

2016-01-01

Highlights: • Nano-HA has been demonstrated as an efficient polysulfide absorbent. • The shuttle effect of polysulfide in Li-S battery has been confined by the nano-HA. • Nano-HA used as additive improved electrochemical performance of Li-S battery. - Abstract: Lithium-sulfur (Li-S) battery is regarded as one of the most promising candidates for developing advanced energy storage system, but the polysulfide shuttle effect remains the biggest obstacle for its practical application. In this work, nano-hydroxyapatite (Ca 5 (PO 4 ) 3 (OH)) was used as an additive in the sulfur cathode and carbon-coated separator to prevent the polysulfide shuttle effect and thus to achieve the high performance. The sulfur cathode with nano-hydroxyapatite exhibited a higher reversible capacity and a more stable cycling performance than that of the pristine sulfur cathode. The improved capacity retention from 58% (100th) to 73% (200th) after introducing nano-hydroxyapatite into the sulfur cathode confirmed its strong polysulfide absorption ability. Furthermore, a nano-hydroxyapatite modified separator was developed to suppress the polysulfide shuttle effect and to facilitate the reutilization of sulfur species. The nano-hydroxyapatite particles served as polysulfide absorbents to bind polysulfides and suppress their diffusion to the anode. The batteries assembled with this separator exhibited a high reversible capacity of 886 mAhg −1 at 0.1C and 718 mAh g −1 at 0.5C after 200 cycles, with a low capacity fading of ∼0.10-0.11% per-cycle. At the highest sulfur loading of 4.5 mg cm −2 used for practical applications, the reversible areal capacity was much higher than the areal capacity (4 mAh cm −2 ) of commercial lithium-ion batteries. Therefore, the strategy using nano-hydroxyapatite as polysulfide absorbent shows great potential for solving the polysulfide shuttle problem and developing high performance Li-S batteries.

NASA Goddards LiDAR, Hyperspectral and Thermal (G-LiHT) Airborne Imager

Science.gov (United States)

Cook, Bruce D.; Corp, Lawrence A.; Nelson, Ross F.; Middleton, Elizabeth M.; Morton, Douglas C.; McCorkel, Joel T.; Masek, Jeffrey G.; Ranson, Kenneth J.; Ly, Vuong; Montesano, Paul M.

2013-01-01

The combination of LiDAR and optical remotely sensed data provides unique information about ecosystem structure and function. Here, we describe the development, validation and application of a new airborne system that integrates commercial off the shelf LiDAR hyperspectral and thermal components in a compact, lightweight and portable system. Goddard's LiDAR, Hyperspectral and Thermal (G-LiHT) airborne imager is a unique system that permits simultaneous measurements of vegetation structure, foliar spectra and surface temperatures at very high spatial resolution (approximately 1 m) on a wide range of airborne platforms. The complementary nature of LiDAR, optical and thermal data provide an analytical framework for the development of new algorithms to map plant species composition, plant functional types, biodiversity, biomass and carbon stocks, and plant growth. In addition, G-LiHT data enhance our ability to validate data from existing satellite missions and support NASA Earth Science research. G-LiHT's data processing and distribution system is designed to give scientists open access to both low- and high-level data products (http://gliht.gsfc.nasa.gov), which will stimulate the community development of synergistic data fusion algorithms. G-LiHT has been used to collect more than 6,500 km2 of data for NASA-sponsored studies across a broad range of ecoregions in the USA and Mexico. In this paper, we document G-LiHT design considerations, physical specifications, instrument performance and calibration and acquisition parameters. In addition, we describe the data processing system and higher-level data products that are freely distributed under NASA's Data and Information policy.

Designing a Sine-Coil for Measurement of Plasma Displacements in IR-T1 Tokamak

International Nuclear Information System (INIS)

Khorshid, Pejman; Razavi, M.; Molaii, M.; Ghoranneviss, M.; TalebiTaher, A.; Arvin, R.; Mohammadi, S.; NikMohammadi, A.

2008-01-01

A method for the measurement of the plasma position in the IR-T1 tokamak in toroidal coordinates is developed. A sine-coil, which is a Rogowski coil with a variable wiring density is designed and fabricated for this purpose. An analytic solution of the Biot-Savart law, which is used to calculate magnetic fields created by toroidal plasma current, is presented. Results of calculations are compared with the experimental data obtained in no-plasma shots with a toroidal current-carrying coil positioned inside the vessel to simulate the plasma movements. The results are shown a good linear behavior of plasma position measurements. The error is less than 2.5% and it is compared with other methods of measurements of the plasma position. This method will be used in the feedback position control system and tests of feedback controller parameters are ongoing

Fabrication of Li{sub 4}SiO{sub 4} pebbles by gel-precipitation technology

Energy Technology Data Exchange (ETDEWEB)

Wen, Z.; Wu, X.; Gu, Z. [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai (China)

2007-07-01

Full text of publication follows: Lithium orthosilicate (Li{sub 4}SiO{sub 4}) is considered as a promising candidate as breeder material for fusion reactors due to its high lithium content, high stability and favorable tritium release behavior. The shape the breeder materials adopted was determined by many factors, such as the tritium breeding ratio, the ease of diffusion of tritium, the release of thermal stress and irradiation cracking etc. At present pebble configuration has been recognized as the preferred option in most blanket designs for tritium breeders. In the fabrication of spheres of a ceramic material, there are several methods available: the agglomeration of powders, melt-spraying method, sol-gel process and gel-precipitation process. Li{sub 4}SiO{sub 4} pebbles with satisfying quality have been fabricated by melt-spraying method. But expensive experimental equipment and high temperature restrict the extensive application of the method. Gel-precipitation can be operated at room temperature and no special equipment is needed. The technique has been successfully used to produce lithium aluminate ceramic spheres. In this work, fabrication of Li{sub 4}SiO{sub 4} pebbles by gel-precipitation technology was first time investigated systematically. LiOH, citric acid and SiO{sub 2} (aerosil) were used as raw materials. SiO{sub 2} (aerosil) was dispersed in the gel formed by LiOH and citric acid, milky suspension was then obtained and Li{sub 4}SiO{sub 4} pebbles were produced from the milky suspension. The pebbles obtained displayed pure Li{sub 4}SiO{sub 4} phase, exhibited high sphericity, uniform distribution in size, small amount of pores and cracks. Phase transformation with the molar ratio of SiO{sub 2}/LiOH was investigated. The effect of sintering temperature on microstructure was discussed. The water-based gel-precipitation method for fabrication of Li{sub 4}SiO{sub 4} spheres was simple and convenient to realize mass production. (authors)

Li2SnO3 derived secondary Li-Sn alloy electrode for lithium-ion batteries

International Nuclear Information System (INIS)

Zhang, D.W.; Zhang, S.Q.; Jin, Y.; Yi, T.H.; Xie, S.; Chen, C.H.

2006-01-01

As a possible high-capacity Li-ion battery anode material, Li 2 SnO 3 was prepared via a solid-state reaction route and a sol-gel route, separately. Its electrochemical performance was tested in coin-type cells with metallic Li as the counter electrode. The results show that the sol-gel derived Li 2 SnO 3 has uniform nano-sized particles (200-300 nm) and can deliver a better reversible capacity (380 mAh/g after 50 cycles in the voltage window of 0-1 V) than that from the solid-state reaction route. The characterizations by means of galvanostatic cycling, cyclic voltammetry and ex situ X-ray diffraction indicate that the electrochemical process of the Li 2 SnO 3 lithiation proceeds with an initial structural reduction of the composite oxide into Sn-metal and Li 2 O followed by a reversible Li-Sn alloy formation in the Li 2 O matrix. Due to the buffer role of the Li 2 O matrix, the reversibility of the secondary Li-Sn alloy electrode is largely secured

Li-rich layer-structured cathode materials for high energy Li-ion batteries

Science.gov (United States)

Li, Liu; Lee, Kim Seng; Lu, Li

2014-08-01

Li-rich layer-structured xLi2MnO3 ṡ (1 - x)LiMO2 (M = Mn, Ni, Co, etc.) materials have attracted much attention due to their extraordinarily high reversible capacity as the cathode material in Li-ion batteries. To better understand the nature of this type of materials, this paper reviews history of development of the Li-rich cathode materials, and provides in-depth study on complicated crystal structures and reaction mechanisms during electrochemical charge/discharge cycling. Despite the fabulous capability at low rate, several drawbacks still gap this type of high-capacity cathode materials from practical applications, for instance the large irreversible capacity loss at first cycle, poor rate capability, severe voltage decay and capacity fade during electrochemical charge/discharge cycling. This review will also address mechanisms for these inferior properties and propose various possible solutions to solve above issues for future utilization of these cathode materials in commercial Li-ion batteries.

Scintillation properties of LiF–SrF2 and LiF–CaF2 eutectic

International Nuclear Information System (INIS)

Yanagida, Takayuki; Kawaguchi, Noriaki; Fujimoto, Yutaka; Fukuda, Kentaro; Watanabe, Kenichi; Yamazaki, Atsushi; Uritani, Akira

2013-01-01

Dopant free eutectic scintillators 6 LiF–SrF 2 and 6 LiF–CaF 2 were developed by the vertical Bridgeman method for the purpose of thermal neutron detection. The molar ratio of LiF and Ca/SrF 2 was 4:1 on its eutectic composition. The α-ray induced radioluminescence spectra of the scintillators showed intense emission peak at 300 nm due to the emission from the self-trapped exciton in Ca/SrF 2 layers. When the samples were irradiated with 252 Cf neutrons, 6 LiF–SrF 2 and 6 LiF–CaF 2 exhibited the light yields of 4700 and 9400 ph/n, respectively. Scintillation decay times of 6 LiF–SrF 2 and 6 LiF–CaF 2 were accepted for scintillation detectors, 90 and 250 ns, respectively. -- Highlights: • Nondoped LiF–CaF 2 and LiF–SrF 2 eutectic scinitillators are reported for the first time. • Two sample showed self-trapped exciton emission. • LiF–SrF 2 sample exhibited the light yield of 9400 ph/n and this value was comparable to conventional materials doped with rare earth ions. • Scintillation decay times of LiF–CaF 2 and LiF–SrF 2 were 250 and 90 ns, respectively

Dielectric properties of Li doped Li-Nb-O thin films

Energy Technology Data Exchange (ETDEWEB)

Perentzis, G.; Horopanitis, E.E.; Papadimitriou, L. [Aristotle University of Thessaloniki, Department of Physics, 54124 Thessaloniki (Greece); Durman, V.; Saly, V.; Packa, J. [Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, 81219 Bratislava (Slovakia)

2007-03-15

Lithium niobate LiNbO{sub 3} was prepared as a thin film layered structure deposited on stainless steel substrate using e-gun evaporation. The Li doping was provided for by the formation of Li-Nb-O/Li/LiNb-O sandwich structure and annealing at about 250 C. AC impedance spectroscopy measurements were performed on the samples at temperatures from the interval between 28 and 165 C and in a frequency range of 10{sup -3} to 10{sup 6} Hz. Using the values Z' and Z'' at different frequencies, the dielectric parameters - parts of the complex permittivity {epsilon}' and {epsilon}'' and loss tangent tan {delta} were calculated. The results prove validity of the proposed equivalent circuit containing parallel RC elements connected in series where the first RC element represents the bulk of material and the second RC element belongs to the double layer at the metal interface. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

LiDAR Scan Matching Aided Inertial Navigation System in GNSS-Denied Environments

OpenAIRE

Tang, Jian; Chen, Yuwei; Niu, Xiaoji; Wang, Li; Chen, Liang; Liu, Jingbin; Shi, Chuang; Hyyppä, Juha

2015-01-01

A new scan that matches an aided Inertial Navigation System (INS) with a low-cost LiDAR is proposed as an alternative to GNSS-based navigation systems in GNSS-degraded or -denied environments such as indoor areas, dense forests, or urban canyons. In these areas, INS-based Dead Reckoning (DR) and Simultaneous Localization and Mapping (SLAM) technologies are normally used to estimate positions as separate tools. However, there are critical implementation problems with each standalone system. Th...

77 FR 40266 - Safety Zone; Conneaut 4th of July Festival, Lake Erie, Conneaut, OH

Science.gov (United States)

2012-07-09

... 1625-AA00 Safety Zone; Conneaut 4th of July Festival, Lake Erie, Conneaut, OH AGENCY: Coast Guard, DHS... the Conneaut 4th of July Festival Fireworks display. This temporary safety zone is necessary to... vessels during the Conneaut 4th of July Festival Fireworks. This zone will be effective and enforced from...

Synthesis and electrochemical properties of Ti4+ doped Li3-xFe2-xTix(PO4)3/C cathode materials

International Nuclear Information System (INIS)

Liu Zhanqiang; Huang Fuqiang; Sun Junkang

2011-01-01

Highlights: → Li 3-x Fe 2-x Ti x (PO 4 ) 3 /C composite cathodes were prepared by ball-milling method. Ti-doping can improve the electrochemical property of Li 3 Fe 2 (PO 4 ) 3 . → The optimized doping level was found to be x = 0.2. → The second phase of LiTi 2 (PO 4 ) 3 will emerge if the doping level higher than 0.2. - Abstract: Li 3-x Fe 2-x Ti x (PO 4 ) 3 /C (x = 0-0.4) cathodes designed with Fe doped by Ti was studied. Both Li 3 Fe 2 (PO 4 ) 3 /C (x = 0) and Li 2.8 Fe 1.8 Ti 0.2 (PO 4 ) 3 /C (x = 0.2) possess two plateau potentials of Fe 3+ /Fe 2+ couple (around 2.8 V and 2.7 V vs. Li + /Li) upon discharge observed from galvanostatic charge/discharge and cyclic voltammetry. Li 2.8 Fe 1.8 Ti 0.2 (PO 4 ) 3 /C has higher reversibility and better capacity retention than that of the undoped Li 3 Fe 2 (PO 4 ) 3 /C. A much higher specific capacity of 122.3 mAh/g was obtained at C/20 in the first cycle, approaching the theoretical capacity of 128 mAh/g, and a capacity of 100.1 mAh/g was held at C/2 after the 20th cycle.

Weixue Li

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science. Weixue Li. Articles written in Bulletin of Materials Science. Volume 29 Issue 3 June 2006 pp 313-316 Composites. Anisotropic properties of aligned SWNT modified poly (methyl methacrylate) nanocomposites · Weixue Li Qing Wang Jianfeng Dai · More Details Abstract Fulltext ...

Robustness of the charge-ordered phases in IrTe2 against photoexcitation

Science.gov (United States)

Monney, C.; Schuler, A.; Jaouen, T.; Mottas, M.-L.; Wolf, Th.; Merz, M.; Muntwiler, M.; Castiglioni, L.; Aebi, P.; Weber, F.; Hengsberger, M.

2018-02-01

We present a time-resolved angle-resolved photoelectron spectroscopy study of IrTe2, which undergoes two first-order structural and charge-ordered phase transitions on cooling below 270 K and below 180 K. The possibility of inducing a phase transition by photoexcitation with near-infrared femtosecond pulses is investigated in the charge-ordered phases. We observe changes of the spectral function occurring within a few hundreds of femtoseconds and persisting up to several picoseconds, which we interpret as a partial photoinduced phase transition (PIPT). The necessary time for photoinducing these spectral changes increases with increasing photoexcitation density and reaches time scales longer than the rise time of the transient electronic temperature. We conclude that the PIPT is driven by a transient increase of the lattice temperature following the energy transfer from the electrons. However, the photoinduced changes of the spectral function are small, which indicates that the low-temperature phase is particularly robust against photoexcitation. We suggest that the system might be trapped in an out-of-equilibrium state, for which only a partial structural transition is achieved.

DISPLAY3D. A Graphics Preprocessor for CHIEF

Science.gov (United States)

1990-12-27

graphics devices, the user may write a graphics program th.,.t can read DISPLAY3D output files, or use one of the commercial plotting packages...COMMON/NBPRTC/IRHSPT, NARSPT, NPTBLK FRQPT COMMON/NBPRTS/SYMTPT CHARACTER*3 SYMTPT DIMENSION CC(10), TRNS(3), IELTS (8,300) real xl(1000) ,yl(leee...C Prompt the user for filename. C--- ------------------------------------------------------- WRITE (6,1) ’Enter filename used in CID or

Electrochemical behavior of LiV3O8 positive electrode in hybrid Li,Na-ion batteries

Science.gov (United States)

Maletti, S.; Sarapulova, A.; Tsirlin, A. A.; Oswald, S.; Fauth, F.; Giebeler, L.; Bramnik, N. N.; Ehrenberg, H.; Mikhailova, D.

2018-01-01

Vanadium(V)-containing oxides show superior intercalation properties for alkaline ions, although the performance of the material strongly depends on its surface morphology. In this work, intercalation activity of LiV3O8, prepared by a conventional solid state synthesis, is demonstrated for the first time in non-aqueous Li,Na-ion hybrid batteries with Na as negative electrode, and different Na/Li ratios in the electrolyte. In the pure Na-ion cell, one Na per formula unit of LiV3O8 can be reversibly inserted at room temperature via a two-step process, while further intercalation leads to gradual amorphisation of the material, with a specific capacity of 190 mAhg-1 after 10 cycles in the potential window of 0.8-3.4 V. Hybrid Li,Na-ion batteries feature simultaneous intercalation of Li+ and Na+ cations into LiV3O8, resulting in the formation of a second phase. Depending on the electrolyte composition, this second phase bears structural similarities either to Li0.7Na0.7V3O8 in Na-rich electrolytes, or to Li4V3O8 in Li-rich electrolytes. The chemical diffusion coefficients of Na+ and Li+ in crystalline LiV3O8 are very close, hence explaining the co-intercalation of these cations. As DFT calculations show, once formed, the Li0.7Na0.7V3O8-type structure favors intercalation of Na+, whereas the LiV3O8-type prefers to accommodate Li+ cations.

Enhanced cycling performance of a Li metal anode in a dimethylsulfoxide-based electrolyte using highly concentrated lithium salt for a lithium-oxygen battery

Science.gov (United States)

Togasaki, Norihiro; Momma, Toshiyuki; Osaka, Tetsuya

2016-03-01

Stable charge-discharge cycling behavior for a lithium metal anode in a dimethylsulfoxide (DMSO)-based electrolyte is strongly desired of lithium-oxygen batteries, because the Li anode is rapidly exhausted as a result of side reactions during cycling in the DMSO solution. Herein, we report a novel electrolyte design for enhancing the cycling performance of Li anodes by using a highly concentrated DMSO-based electrolyte with a specific Li salt. Lithium nitrate (LiNO3), which forms an inorganic compound (Li2O) instead of a soluble product (Li2S) on a lithium surface, exhibits a >20% higher coulombic efficiency than lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, and lithium perchlorate, regardless of the loading current density. Moreover, the stable cycling of Li anodes in DMSO-based electrolytes depends critically on the salt concentration. The highly concentrated electrolyte 4.0 M LiNO3/DMSO displays enhanced and stable cycling performance comparable to that of carbonate-based electrolytes, which had not previously been achieved. We suppose this enhancement is due to the absence of free DMSO solvent in the electrolyte and the promotion of the desolvation of Li ions on the solid electrolyte interphase surface, both being consequences of the unique structure of the electrolyte.

Li interactions with the B40 fullerene and its application in Li-ion batteries: DFT studies

Science.gov (United States)

Moradi, Morteza; Bagheri, Zargham; Bodaghi, Ali

2017-05-01

The interaction of Li and Li+ with a B40 all-boron fullerene was theoretically investigated at the B3LYP, and Minnesota 2006 levels of theory. It was found that, unexpectedly, the interaction Li+ cation with the electron deficient B40 fullerene is stronger than the Li atom. It indicates that the B40 fullerene does not act as a conventional Lewis acid because of its highly correlated structure. Frontier molecular orbitals, partial density of states, and natural bond orbital analyses were used to discuss this unusual behavior. Our calculations indicate that this behavior makes the B40 fullerene more appropriate for application in the Li-ion batteries as anode material. The calculated cell voltage is about 530 mV. Also, it was found that Hartree Fock (HF) exchange percentage of density functionals has a reverse effect on the adsorption energies of Li and Li+. This energy is increased and decreased, respectively, for Li+ and Li adsorptions by increasing %HF exchange. Finally, a potential energy surface for Li and Li+ penetration into B40 fullerene was predicted.

Association and Diffusion of Li(+) in Carboxymethylcellulose Solutions for Environmentally Friendly Li-ion Batteries.

Science.gov (United States)

Casalegno, Mosè; Castiglione, Franca; Passarello, Marco; Mele, Andrea; Passerini, Stefano; Raos, Guido

2016-07-21

Carboxymethylcellulose (CMC) has been proposed as a polymeric binder for electrodes in environmentally friendly Li-ion batteries. Its physical properties and interaction with Li(+) ions in water are interesting not only from the point of view of electrode preparation-processability in water is one of the main reasons for its environmental friendliness-but also for its possible application in aqueous Li-ion batteries. We combine molecular dynamics simulations and variable-time pulsed field gradient spin-echo (PFGSE) NMR spectroscopy to investigate Li(+) transport in CMC-based solutions. Both the simulations and experimental results show that, at concentrations at which Li-CMC has a gel-like consistency, the Li(+) diffusion coefficient is still very close to that in water. These Li(+) ions interact preferentially with the carboxylate groups of CMC, giving rise to a rich variety of coordination patterns. However, the diffusion of Li(+) in these systems is essentially unrestricted, with a fast, nanosecond-scale exchange of the ions between CMC and the aqueous environment. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Approaching the Type-II Dirac Point and Concomitant Superconductivity in Pt-doping Stabilized Metastable 1T-phase IrTe2

OpenAIRE

Fei, Fucong; Bo, Xiangyan; Wang, Pengdong; Ying, Jianghua; Chen, Bo; Liu, Qianqian; Zhang, Yong; Sun, Zhe; Qu, Fanming; Zhang, Yi; Li, Jian; Song, Fengqi; Wan, Xiangang; Wang, Baigeng; Wang, Guanghou

2017-01-01

Topological semimetal is a topic of general interest in material science. Recently, a new kind of topological semimetal called type-II Dirac semimetal with tilted Dirac cones is discovered in PtSe2 family. However, the further investigation is hindered due to the huge energy difference from Dirac points to Fermi level and the irrelevant conducting pockets at Fermi surface. Here we characterize the optimized type-II Dirac dispersions in a metastable 1T phase of IrTe2. Our strategy of Pt doping...

Reversible Li storage for nanosize cation/anion-disordered rocksalt-type oxyfluorides: LiMoO2 - x LiF (0 ≤ x ≤ 2) binary system

Science.gov (United States)

Takeda, Nanami; Hoshino, Satoshi; Xie, Lixin; Chen, Shuo; Ikeuchi, Issei; Natsui, Ryuichi; Nakura, Kensuke; Yabuuchi, Naoaki

2017-11-01

A binary system of LiMoO2 - x LiF (0 ≤ x ≤ 2), Li1+xMoO2Fx, is systematically studied as potential positive electrode materials for rechargeable Li batteries. Single phase and nanosized samples on this binary system are successfully prepared by using a mechanical milling route. Crystal structures and Li storage properties on the binary system are also examined. Li2MoO2F (x = 1), which is classified as a cation-/anion-disordered rocksalt-type structure and is a thermodynamically metastable phase, delivers a large reversible capacity of over 300 mAh g-1 in Li cells with good reversibility. Highly reversible Li storage is realized for Li2MoO2F consisting of nanosized particles based on Mo3+/Mo5+ two-electron redox as evidenced by ex-situ X-ray absorption spectroscopy coupled with ex-situ X-ray diffractometry. Moreover, the presence of the most electronegative element in the framework structure effectively increases the electrode potential of Mo redox through an inductive effect. From these results, potential of nanosized lithium molybdenum oxyfluorides for high-capacity positive electrode materials of rechargeable Li batteries are discussed.

A comparative structural and electrochemical study of monoclinic Li3V2(PO4)3/C and rhombohedral Li2.5Na0.5V(2−2x/3)Nix(PO4)3/C

International Nuclear Information System (INIS)

Wang, Wenhui; Chen, Zhenyu; Zhang, Jiaolong; Dai, Changsong; Li, Jiajie; Ji, Dalong

2013-01-01

In order to synthesize pure derivative of rhombohedral Li 3 V 2 (PO 4 ) 3 (LVP), lithium-ion batteries materials Li 2.5 Na 0.5 V (2−2x/3) Ni x (PO 4 ) 3 /C (x = 0.03, 0.06, 0.09) and its control, monoclinic Li 3 V 2 (PO 4 ) 3 /C (LVP/C), were prepared by sol–gel method. The samples were investigated by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) spectroscopy, scanning electron microscopy (SEM), Raman spectroscopy, and electrochemical methods. The XRD patterns of Li 2.5 Na 0.5 V (2−2x/3) Ni x (PO 4 ) 3 /C are in good agreement with that of rhombohedral LVP, which indicates that the Na + –Ni 2+ composite doping can change the structure of monoclinic LVP. All the composite doping samples displayed a single flat plateau at 3.7 V in the charge/discharge voltage profile, which is caused by transformation of multi-phase mechanism to single-phase mechanism. For Li 2.5 Na 0.5 V 1.98 Ni 0.03 (PO 4 ) 3 /C, a specific discharge capacity of 108 mAh g −1 was achieved at a 0.5 C charge rate and a 1 C discharge rate, and a 99.0% retention rate of the initial capacity was obtained after 50 cycles

Irradiation cryostat for LiH and LiD polarized solid targets

International Nuclear Information System (INIS)

Goertz, S.

1991-01-01

Scattering experiments with polarized nucleon targets are an important tool to understand the nuclear spin structure. Pion photoproduction experiments on polarized protrons and neutrons as well as measurements of the neutron and deuteron formfactors will be performed at ELSA. 7 LiH and 6 LiD seem to be attractive target materials for these experiments, because they offer high proton and deuteron polarisation, respectively. Expecially 6 LiD has further very important advantages compared to the common deuteron target materials as d-Butanol and ND 3 . This work describes the mechanism of DNP (Dynamic Nuclear Polarization) in LiH and LiD and gives a view on the nature of the so-called paramagnetic impurities in these materials. In order to maximize the nuclear polarization, the production of these radicals have to take place under well defined temperature conditions. Therefore the first version of an irradiation cryostat was built and tested in regard to its cooling power and temperature adjustment. (orig.)

Sedimentary input into the source of Martinique lavas: a Li perspective

Science.gov (United States)

Tang, M.; Chauvel, C.; Rudnick, R. L.

2013-12-01

The Lesser Antilles arc is known for the prominent continental crustal signatures in its lavas. It thus provides an ideal target for studying crustal recycling in subduction zones. Martinique Island, located in the middle of the Lesser Antilles arc, has been well characterized for its elemental and radiogenic isotope geochemistry (Labanieh et al., 2012). We measured Li isotopes in the Martinique lavas as well as sediments cored at the southern (Site 144) and northern part (Site 543) of the subducting slab. The sediments show a large isotopic variation (δ7Li ~ -4.2‰ to +3.2‰) but the average δ7Li of -1.1 × 2.4‰ (1 σ, n = 15) is significantly lower than that of N-MORB (δ7Li = + 3.4 × 0.7‰, 1 σ, Tomascak et al., 2008), reflecting the influence of chemical weathering in the continental provenance. Although the subducting sediments display marked mineralogical and chemical shifts from south to north due to different deposition distances to the continental platform (Carpentier et al., 2009), their average Li isotopic compositions are indiscernible from each other. With a few exceptions, the Li isotopic compositions of the Martinique lavas are systematically lighter than MORB, giving an average δ7Li of 1.6 × 1.4‰ (1 σ, n = 25, 4 exceptions excluded). The δ7Li values show no correlation with any radiogenic isotope ratios (206Pb/204Pb, 87Sr/86Sr, 143Nd/144Nd and 176Hf/177Hf), Li/Y ratio, La/Sm ratio and SiO2 content. Therefore, the light Li isotopic composition likely reflects the source characteristics rather than contamination within the arc crust. Incorporation of the isotopically light sediments from Site 144 and 543 in the source may explain the depletion of 7Li in the Martinique lavas. A two-end-member mixing model requires 2-5% addition of the sediments into the depleted mantle source, compared with 1-10% sediments constrained by radiogenic isotopes (Carpentier et al., 2008). References Carpentier, M., Chauvel, C., & Mattielli, N., 2008. Pb

Li-ion batteries: Phase transition

International Nuclear Information System (INIS)

Hou Peiyu; Zhang Yantao; Zhang Lianqi; Chu Geng; Gao Jian

2016-01-01

Progress in the research on phase transitions during Li + extraction/insertion processes in typical battery materials is summarized as examples to illustrate the significance of understanding phase transition phenomena in Li-ion batteries. Physical phenomena such as phase transitions (and resultant phase diagrams) are often observed in Li-ion battery research and already play an important role in promoting Li-ion battery technology. For example, the phase transitions during Li + insertion/extraction are highly relevant to the thermodynamics and kinetics of Li-ion batteries, and even physical characteristics such as specific energy, power density, volume variation, and safety-related properties. (topical review)

Contribution to understanding the post-mining landscape - Application of airborn LiDAR and historical maps at the example from Silesian Upland (Poland)

Science.gov (United States)

Gawior, D.; Rutkiewicz, P.; Malik, I.; Wistuba, M.

2017-11-01

LiDAR data provide new insights into the historical development of mining industry recorded in the topography and landscape. In the study on the lead ore mining in the 13th-17th century we identified remnants of mining activity in relief that are normally obscured by dense vegetation. The industry in Tarnowice Plateau was based on exploitation of galena from the bedrock. New technologies, including DEM from airborne LiDAR provide show that present landscape and relief of post-mining area under study developed during several, subsequent phases of exploitation when different techniques of exploitation were used and probably different types of ores were exploited. Study conducted on the Tarnowice Plateau proved that combining GIS visualization techniques with historical maps, among all geological maps, is a promising approach in reconstructing development of anthropogenic relief and landscape..

Complex Diffusion Mechanisms for Li in Feldspar: Re-thinking Li-in-Plag Geospeedometry

Science.gov (United States)

Holycross, M.; Watson, E. B.

2017-12-01

In recent years, the lithium isotope system has been applied to model processes in a wide variety of terrestrial environments. In igneous settings, Li diffusion gradients have been frequently used to time heating episodes. Lithium partitioning behavior during decompression or cooling events drives Li transfer between phases, but the extent of Li exchange may be limited by its diffusion rate in geologic materials. Lithium is an exceptionally fast diffuser in silicate media, making it uniquely suited to record short-lived volcanic phenomena. The Li-in-plagioclase geospeedometer is often used to time explosive eruptions by applying laboratory-calibrated Li diffusion coefficients to model concentration profiles in magmatic feldspar samples. To quantify Li transport in natural scenarios, experimental measurements are needed that account for changing temperature and oxygen fugacity as well as different feldspar compositions and crystallographic orientation. Ambient pressure experiments were run at RPI to diffuse Li from a powdered spodumene source into polished sanidine, albite, oligoclase or anorthite crystals over the temperature range 500-950 ºC. The resulting 7Li concentration gradients developed in the mineral specimens were evaluated using laser ablation ICP-MS. The new data show that Li diffusion in all feldspar compositions simultaneously operates by both a "fast" and "slow" diffusion mechanism. Fast path diffusivities are similar to those found by Giletti and Shanahan [1997] for Li diffusion in plagioclase and are typically 10 to 20 times greater than slow path diffusivities. Lithium concentration gradients in the feldspar experiments plot in the shape of two superimposed error function curves with the slow diffusion regime in the near-surface of the crystal. Lithium diffusion is most sluggish in sanidine and is significantly faster in the plagioclase feldspars. It is still unclear what diffusion mechanism operates in nature, but the new measurements may impact

Modeling Li-ion conductivity in LiLa(PO{sub 3}){sub 4} powder

Energy Technology Data Exchange (ETDEWEB)

Mounir, Ferhi, E-mail: ferhi.mounir@gmail.com [Laboratoire de Physicochimie des Materiaux Mineraux et leurs Applications, Centre National des Recherches en Sciences des Materiaux, BP No. 73, 8027 Soliman (Tunisia); Karima, Horchani-Naifer [Laboratoire de Physicochimie des Materiaux Mineraux et leurs Applications, Centre National des Recherches en Sciences des Materiaux, BP No. 73, 8027 Soliman (Tunisia); Khaled, Ben Saad [Laboratoire de Photovoltaieque, Centre des Recherches et des Technologies de l' Energie, Technopole Borj Cedria, BP No. 95, 2050 Hammam Lif (Tunisia); Mokhtar, Ferid [Laboratoire de Physicochimie des Materiaux Mineraux et leurs Applications, Centre National des Recherches en Sciences des Materiaux, BP No. 73, 8027 Soliman (Tunisia)

2012-07-01

Polycrystalline powder and single-crystal of LiLa(PO{sub 3}){sub 4} are synthesized by solid state reaction and flux technique, respectively. A morphological description of the obtained product was made based on scanning electron microscopy micrographs. The obtained powder was characterized by X-ray powder diffraction, FTIR and Raman spectroscopies. Ionic conductivity of the LiLa(PO{sub 3}){sub 4} powder was measured and evaluated over a temperature range from 553 to 913 K. Single crystals of LiLa(PO{sub 3}){sub 4} are characterized by single-crystal X-ray diffraction. The LiLa(PO{sub 3}){sub 4} structure was found to be isotypic with LiNd(PO{sub 3}){sub 4}. It crystallizes in the monoclinic system with space group C2/c and cell parameters: a=16.635(6) A, b=7.130(3) A, c=9.913(3) A, {beta}=126.37(4) Degree-Sign , V=946.72(6) A{sup 3} and Z=4. The LiLa(PO{sub 3}){sub 4} structure was described as an alternation between spiraling chains (PO{sub 3}){sub n} and (La{sup 3+}, Li{sup +}) cations along the b direction. The small Li{sup +} ions, coordinated to four oxygen atoms, were located in the large connected cavities created between the LaO{sub 8} polyhedra and the polyphosphate chains. The jumping of Li{sup +} through tunnels of the crystalline network was investigated using complex impedance spectroscopy. The close value of the activation energies calculated through the analysis of conductivity data and loss spectra indicate that the transport in the investigated system is through hopping mechanism. The correlation between ionic conductivity of LiLa(PO{sub 3}){sub 4} and its crystallographic structure was investigated and the most probably transport pathway model was determined.

Structure of chaotic magnetic field lines in IR-T1 tokamak due to ergodic magnetic limiter

Science.gov (United States)

Ahmadi, S.; Salar Elahi, A.; Ghorannevis, M.

2018-03-01

In this paper we have studied an Ergodic Magnetic Limiter (EML) based chaotic magnetic field for transport control in the edge plasma of IR-T1 tokamak. The resonance created by the EML causes perturbation of the equilibrium field line in tokamak and as a result, the field lines are chaotic in the vicinity of the dimerized island chains. Transport barriers are formed in the chaotic field line and actually observe in tokamak with reverse magnetic shear. We used area-preserving non-twist (and twist) Poincaré maps to describe the formation of transport barriers, which are actually features of Hamiltonian systems. This transport barrier is useful in reducing radial diffusion of the field line and thus improving the plasma confinement.

Structure of chaotic magnetic field lines in IR-T1 tokamak due to ergodic magnetic limiter

Directory of Open Access Journals (Sweden)

S. Ahmadi

2018-03-01

Full Text Available In this paper we have studied an Ergodic Magnetic Limiter (EML based chaotic magnetic field for transport control in the edge plasma of IR-T1 tokamak. The resonance created by the EML causes perturbation of the equilibrium field line in tokamak and as a result, the field lines are chaotic in the vicinity of the dimerized island chains. Transport barriers are formed in the chaotic field line and actually observe in tokamak with reverse magnetic shear. We used area-preserving non-twist (and twist Poincaré maps to describe the formation of transport barriers, which are actually features of Hamiltonian systems. This transport barrier is useful in reducing radial diffusion of the field line and thus improving the plasma confinement.

Study of the Effects on Student Knowledge and Perceptions of Activities Related to Submetering the 6th Grade Wing of a Middle School, to Displaying the Carbon Footprint, and to Efforts to Reduce Energy Consumption and Greenhouse Gases

Science.gov (United States)

Peck, Rick

2009-01-01

The purpose of the study was to determine the effects upon student knowledge and perceptions regarding greenhouse gas emissions as a result of an intervention relying upon the submetering the 6th grade wing of a Middle School, displaying the information regarding electrical consumption and carbon footprint, and reducing the electrical consumption…

Electrochemical behavior of nanostructured MnO2/C (Vulcan® composite in aqueous electrolyte LiNO3

Directory of Open Access Journals (Sweden)

Vujković Milica

2011-01-01

Full Text Available The electrolytic solutions of contemporary Li-ion batteries are made exclusively with the organic solvents since anodic materials of these batteries have potentials with greater negativity than the potential of the water reduction, thus the organic electrolytes can withstand the voltages of 3-5 V that are characteristic for these batteries. Ever since it was discovered that some materials can electrochemically intercalate and deintercalate Li+ ions in aqueous solutions, numerous studies have been conducted with the aim of extending operational time of the aqueous Li-ion batteries. Manganese oxide has been studied as the electrode material in rechargeable lithium-ion batteries with organic electrolytes. In this paper its electrochemical behavior as an anode material in aqueous electrolyte solutions was examined. MnO2 as a component of nanodispersed MnO2/C (Vulcan® composite was successfully synthesized hydrothermally. Electrochemical properties of this material were investigated in aqueous saturated LiNO3 solution by both cyclic voltammetry and galvanostatic charging/discharging (LiMn2O4 as cathode material techniques. The obtained composite shows a relatively good initial discharge capacity of 96.5 mAh/g which, after 50th charging/discharging cycles, drops to the value of 57mAh/g. MnO2/C (Vulcan® composite, in combination with LiMn2O4 as a cathode material, shows better discharge capacity compared to other anodic materials used in aqueous Li-ion batteries according to certain studies that have been conducted. Its good reversibility and cyclability, and the fact that hydrothermal method is simple and effective, makes MnO2/C(Vulcan® composite a promising anodic material for aqueous Li-ion batteries.

A MATLAB Package for Markov Chain Monte Carlo with a Multi-Unidimensional IRT Model

Directory of Open Access Journals (Sweden)

Yanyan Sheng

2008-11-01

Full Text Available Unidimensional item response theory (IRT models are useful when each item is designed to measure some facet of a unified latent trait. In practical applications, items are not necessarily measuring the same underlying trait, and hence the more general multi-unidimensional model should be considered. This paper provides the requisite information and description of software that implements the Gibbs sampler for such models with two item parameters and a normal ogive form. The software developed is written in the MATLAB package IRTmu2no. The package is flexible enough to allow a user the choice to simulate binary response data with multiple dimensions, set the number of total or burn-in iterations, specify starting values or prior distributions for model parameters, check convergence of the Markov chain, as well as obtain Bayesian fit statistics. Illustrative examples are provided to demonstrate and validate the use of the software package.

THE NEW DETECTIONS OF 7Li/6Li ISOTOPIC RATIO IN THE INTERSTELLAR MEDIA

International Nuclear Information System (INIS)

Kawanomoto, S.; Kajino, T.; Aoki, W.; Ando, H.; Noguchi, K.; Tanaka, W.; Bessell, M.; Suzuki, T. K.; Honda, S.; Izumiura, H.; Kambe, E.; Okita, K.; Watanabe, E.; Yoshida, M.; Sadakane, K.; Sato, B.; Tajitsu, A.; Takada-Hidai, M.

2009-01-01

We have determined the isotopic abundance ratio of 7 Li/ 6 Li in the interstellar media (ISMs) along lines of sight to HD169454 and HD250290 using the High-Dispersion Spectrograph on the Subaru Telescope. We also observed ζ Oph for comparison with previous data. The observed abundance ratios were 7 Li/ 6 Li = 8.1 +3.6 -1.8 and 6.3 +3.0 -1.7 for HD169454 and HD250290, respectively. These values are in reasonable agreement with those observed previously in the solar neighborhood ISMs within ±2σ error bars and are also consistent with our measurement of 7 Li/ 6 Li = 7.1 +2.9 -1.6 for a cloud along the line of sight to ζ Oph. This is good evidence for homogeneous mixing and instantaneous recycling of the gas component in the Galactic disk. We also discuss several source compositions of 7 Li, Galactic cosmic-ray interactions, stellar nucleosynthesis, and big bang nucleosynthesis.

Structural and electrochemical studies of PPy/PEG-LiFePO4 cathode material for Li-ion batteries

International Nuclear Information System (INIS)

Fedorkova, Andrea; Nacher-Alejos, Ana; Gomez-Romero, Pedro; Orinakova, Renata; Kaniansky, Dusan

2010-01-01

A simple chemical oxidative polymerization of pyrrole (Py) directly onto the surface of LiFePO 4 particles was applied to the synthesis of polypyrrole-LiFePO 4 (PPy-LiFePO 4 ) powder. The LiFePO 4 sample without carbon coating was synthesized by a solvothermal method. The polyethylene glycol (PEG) was used as additive during Py polymerization for increasing the PPy-LiFePO 4 conductivity. Properties of resulting LiFePO 4 , PPy-LiFePO 4 and PPy/PEG-LiFePO 4 samples were characterized by XRD, SEM, TGA and galvanostatic charge-discharge measurements. These methods confirmed the presence of polypyrrole on LiFePO 4 particles and its homogeneous distribution in the resulting powder material. The PPy/PEG-LiFePO 4 composites show higher discharge capacity than pure LiFePO 4 , as PPy/PEG network improves the electron conductivity. It presents specific discharge capacity of 153 mAh/g at C/5 rate.

Residual salt separation from simulated spent nuclear fuel reduced in a LiCl-Li2O salt

International Nuclear Information System (INIS)

Hur, Jin-Mok; Hong, Sun-Seok; Seo, Chung-Seok

2006-01-01

The electrochemical reduction of spent nuclear fuel in LiCl-Li 2 O molten salt for the conditioning of spent nuclear fuel requires the separation of the residual salts from a reduced metal product after the reduction process. Considering the behavior of spent nuclear fuel during the electrochemical reduction process, a surrogate material matrix was constructed and inactive tests on a salt separation were carried out to produce the data required for active tests. Fresh uranium metal prepared from the electrochemical reduction of U 3 O 8 powder was used as the surrogates of the spent nuclear fuel Atomic Energy Society of Japan, Tokyo, Japan, All rights reservedopyriprocess. LiCl, Li 2 O, Y 2 O 3 and SrCl 2 were selected as the components of the residual salts. Interactions between the salts and their influence on the separation of the residual salts were analyzed by differential scanning calorimetry (DSC) and thermogravimetry (TG). Eutectic melting of LiCl-Li 2 O and LiCl-SrCl 2 led to a melting point which was lower than that of the LiCl molten salt was observed. Residual salts were separated by a vaporization method. Co-vaporization of LiCl-Li 2 O and LiCl-SrCl 2 was achieved below the temperatures which could make the uranium metal oxidation by Li 2 O possible. The salt vaporization rates at 950degC were measured as follows: LiCl-8 wt% Li 2 O>LiCl>LiCl-8 wt% SrCl 2 >SrCl 2 . (author)

Residual Salt Separation from the Metal Products Reduced in a LiCl-Li2O Molten Salt

International Nuclear Information System (INIS)

Hur, Jin Mok; Hong, Sun Seok; Kang, Dae Seung; Jeong, Meong Soo; Seo, Chung Seok

2006-02-01

The electrochemical reduction of spent nuclear fuel in a LiCl-Li 2 O molten salt for the conditioning of spent nuclear fuel requires the separation of the residual salts from a reduced metal product after the reduction process. Considering the behavior of spent nuclear fuel during the electrochemical reduction process, a surrogate material matrix was constructed and inactive tests on a salt separation were carried out to produce the data required for the active tests. Fresh uranium metal prepared from the electrochemical reduction of U 3 O 8 powder was used as the surrogates of the spent nuclear fuel components which might be metallized by the electrochemical reduction process. LiCl, Li 2 O, Y 2 O 3 and SrCl 2 were selected as the components of the residual salts. Interactions between the salts and their influence on the separation of the residual salts were analyzed by differential scanning calorimetry (DSC) and thermogravimetry (TG). Eutectic melting of LiCl-Li 2 O and LiCl-SrCl 2 led to a melting point which was lower than that of a LiCl molten salt was observed. Residual salts were separated by a vaporization method. Co-vaporization of LiCl-Li 2 O and LiCl-SrCl 2 was achieved below temperatures which could make the uranium metal oxidation by Li 2 O possible. The salt vaporization rates at 950 .deg. C were measured as follows: LiCl-8 wt% Li 2 O > LiCl > LiCl-8 wt% SrCl 2 > SrCl 2

Plasma column displacement measurements by modified Rogowski sine-coil and Biot-Savart/magnetic flux equation solution on IR-T1 tokamak

International Nuclear Information System (INIS)

Razavi, M.; Mollai, M.; Khorshid, P.; Nedzelskiy, I.; Ghoranneviss, M.

2010-01-01

The modified Rogowski sine-coil (MRSC) has been designed and implemented for the plasma column horizontal displacement measurements on small IR-T1 tokamak. MRSC operation has been examined on test assembly and tokamak. Obtained results show high sensitivity to the plasma column horizontal displacement and negligible sensitivity to the vertical displacement; linearity in wide, ±0.1 m, range of the displacements; and excellent, 1.5%, agreement with the results of numerical solution of Biot-Savart and magnetic flux equations.

Configuring PSx tetrahedral clusters in Li-excess Li7P3S11 solid electrolyte

Directory of Open Access Journals (Sweden)

Wo Dum Jung

2018-04-01

Full Text Available We demonstrate that the Li-ion conductivity can be improved by adding a certain amount of Li (x = 0.25–0.5 as a charge carrier to the composition of glass-ceramic Li7+xP3S11. Structural analysis clarified that the structural changes caused by the ratio of ortho-thiophosphate tetrahedra PS43− and pyro-thiophosphate ditetrahedra P2S74− affect the Li-ion conductivity. The ratio of PS43− and P2S74− varies depending on x and the highest Li-ion conductivity (2.5 × 10−3 S cm−1 at x = 0.25. All-solid-state LiNi0.8Co0.15Al0.05O2/Li7.25P3S11/In-metal cell exhibits the discharge capacity of 106.2 mAh g−1. This ion conduction enhancement from excess Li is expected to contribute to the future design of sulfide-type electrolytes.

Conformational basis for the Li(+)-induced leak current in the rat gamma-aminobutyric acid (GABA) transporter-1

DEFF Research Database (Denmark)

MacAulay, Nanna; Zeuthen, Thomas; Gether, Ulrik

2002-01-01

The rat gamma-aminobutyric acid transporter-1 (GAT-1) was expressed in Xenopus laevis oocytes and the substrate-independent Li(+)-induced leak current was examined using two-electrode voltage clamp. The leak current was not affected by the addition of GABA and was not due to H(+) permeation. The Li......(+)-bound conformation of the protein displayed a lower passive water permeability than that of the Na(+)- and choline (Ch(+))-bound conformations and the leak current did not saturate with increasing amounts of Li(+) in the test solution. The mechanism that gives rise to the leak current did not support active water...... transport in contrast to the mechanism responsible for GABA translocation (approximately 330 water molecules per charge). Altogether, these data support the distinct nature of the leak conductance in relation to the substrate translocation process. It was observed that the leak current was inhibited by low...

Li diffusion and the effect of local structure on Li mobility in Li2O-SiO2 glasses.

Science.gov (United States)

Bauer, Ute; Welsch, Anna-Maria; Behrens, Harald; Rahn, Johanna; Schmidt, Harald; Horn, Ingo

2013-12-05

Aimed to improve the understanding of lithium migration mechanisms in ion conductors, this study focuses on Li dynamics in binary Li silicate glasses. Isotope exchange experiments and conductivity measurements were carried out to determine self-diffusion coefficients and activation energies for Li migration in Li2Si3O7 and Li2Si6O13 glasses. Samples of identical composition but different isotope content were combined for diffusion experiments in couples or triples. Diffusion profiles developed between 511 and 664 K were analyzed by femtosecond laser ablation combined with multiple collector inductively coupled plasma mass spectrometry (fs LA-MC-ICP-MS) and secondary ion mass spectrometry (SIMS). Analyses of diffusion profiles and comparison of diffusion data reveal that the isotope effect of lithium diffusion in silicate glasses is rather small, consistent with classical diffusion behavior. Ionic conductivity of glasses was measured between 312 and 675 K. The experimentally obtained self-diffusion coefficient, D(IE), and ionic diffusion coefficient, D(σ), derived from specific DC conductivity provided information about correlation effects during Li diffusion. The D(IE)/D(σ) is higher for the trisilicate (0.27 ± 0.05) than that for the hexasilicate (0.17 ± 0.02), implying that increasing silica content reduces the efficiency of Li jumps in terms of long-range movement. This trend can be rationalized by structural concepts based on nuclear magnetic resonance (NMR) and Raman spectroscopy as well as molecular dynamic simulations, that is, lithium is percolating in low-dimensional, alkali-rich regions separated by a silica-rich matrix.

Stannic oxide spherical nanoparticles: an anode material with long-term cyclability for Li-ion rechargeable batteries

Science.gov (United States)

Kalubarme, Ramchandra S.; Kale, Bharat B.; Gosavi, Suresh W.

2017-08-01

Transition metal oxides are widely used in energy storage applications. Stannic oxide nanostructures are prepared using a controlled, NaOH assisted, simple precipitation method. The morphology of the prepared material confirms the formation of fine nanoparticles having a rutile stannic oxide (SnO2) phase, with cassiterite structure, and size distribution ~20 nm. On testing, as an anode material for a Li-ion battery, stannic oxide delivers a reversible charge capacity of 957 mAh g-1 at an applied current rate of C/10. The stannic oxide shows excellent rate performance displaying capacity of 577 mAh g-1 at 10 C and capacity of 919 mAh g-1 retained after 200 cycles at an applied current rate of C/2. The super performance of stannic oxide fine particles stem from both the effective diffusion of Li-ions to reaction sites through porous channels and weaker stress/strain during Li insertion/desertion owing to its fine size.

Perturbation theory of a symmetric center within Liénard equations

Science.gov (United States)

Françoise, Jean-Pierre; Xiao, Dongmei

2015-09-01

In this article, we introduce the use of Lambert function to develop further the global perturbation theory of an integrable Liénard equation which displays a symmetric center. We prove a global Morse lemma for the first integral and deduce the existence of an associated Picard-Fuchs system. We revisit previous contributions to first-order perturbation theory with the help of these new analytic techniques and in particular, we check that the fundamental integrals are linearly independent. The Lambert function allows to find an expansion formula for these integrals. We also study the possibility to develop a higher-order perturbation theory. The algorithm of the successive derivatives works in general in the class of analytic functions on the domain D where the level sets of the first integral are ovals. We end the article with some results on the first integral of a symmetric Liénard equation deduced from the algorithm of successive derivatives.

The transcription factors Runx3 and ThPOK cross-regulate acquisition of cytotoxic function by human Th1 lymphocytes

Science.gov (United States)

Defrance, Matthieu; Vu Manh, Thien-Phong; Azouz, Abdulkader; Detavernier, Aurélie; Hoyois, Alice; Das, Jishnu; Bizet, Martin; Pollet, Emeline; Tabbuso, Tressy; Calonne, Emilie; van Gisbergen, Klaas; Dalod, Marc; Fuks, François; Goriely, Stanislas

2018-01-01

Cytotoxic CD4 (CD4CTX) T cells are emerging as an important component of antiviral and antitumor immunity, but the molecular basis of their development remains poorly understood. In the context of human cytomegalovirus infection, a significant proportion of CD4 T cells displays cytotoxic functions. We observed that the transcriptional program of these cells was enriched in CD8 T cell lineage genes despite the absence of ThPOK downregulation. We further show that establishment of CD4CTX-specific transcriptional and epigenetic programs occurred in a stepwise fashion along the Th1-differentiation pathway. In vitro, prolonged activation of naive CD4 T cells in presence of Th1 polarizing cytokines led to the acquisition of perforin-dependent cytotoxic activity. This process was dependent on the Th1 transcription factor Runx3 and was limited by the sustained expression of ThPOK. This work elucidates the molecular program of human CD4CTX T cells and identifies potential targets for immunotherapy against viral infections and cancer. PMID:29488879

Epitaxial thin film growth of LiH using a liquid-Li atomic template

International Nuclear Information System (INIS)

Oguchi, Hiroyuki; Ikeshoji, Tamio; Orimo, Shin-ichi; Ohsawa, Takeo; Shiraki, Susumu; Hitosugi, Taro; Kuwano, Hiroki

2014-01-01

We report on the synthesis of lithium hydride (LiH) epitaxial thin films through the hydrogenation of a Li melt, forming abrupt LiH/MgO interface. Experimental and first-principles molecular dynamics studies reveal a comprehensive microscopic picture of the crystallization processes, which sheds light on the fundamental atomistic growth processes that have remained unknown in the vapor-liquid-solid method. We found that the periodic structure that formed, because of the liquid-Li atoms at the film/MgO-substrate interface, serves as an atomic template for the epitaxial growth of LiH crystals. In contrast, films grown on the Al 2 O 3 substrates indicated polycrystalline films with a LiAlO 2 secondary phase. These results and the proposed growth process provide insights into the preparation of other alkaline metal hydride thin films on oxides. Further, our investigations open the way to explore fundamental physics and chemistry of metal hydrides including possible phenomena that emerge at the heterointerfaces of metal hydrides

77 FR 35619 - Safety Zone; Old Fashion 4th July Fireworks, Presque Isle Bay, Erie, PA

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2012-06-14

...-AA00 Safety Zone; Old Fashion 4th July Fireworks, Presque Isle Bay, Erie, PA AGENCY: Coast Guard, DHS... during the Old Fashion 4th July Fireworks display. This temporary safety zone is necessary to protect... ensure the safety of spectators and vessels during the Old Fashion 4th July Fireworks. [[Page 35620...

Fabrication of Li-intercalated bilayer graphene

Directory of Open Access Journals (Sweden)

K. Sugawara

2011-06-01

Full Text Available We have succeeded in fabricating Li-intercalated bilayer graphene on silicon carbide. The low-energy electron diffraction from Li-deposited bilayer graphene shows a sharp 3×3R30° pattern in contrast to Li-deposited monolayer graphene. This indicates that Li atoms are intercalated between two adjacent graphene layers and take the same well-ordered superstructure as in bulk C6Li. The angle-resolved photoemission spectroscopy has revealed that Li atoms are fully ionized and the π bands of graphene are systematically folded by the superstructure of intercalated Li atoms, producing a snowflake-like Fermi surface centered at the Γ point. The present result suggests a high potential of Li-intercalated bilayer graphene for application to a nano-scale Li-ion battery.

The possibility of creating a new low power nuclear facility with slightly enriched nuclear fuel on the basis of the decommissioned IRT-M reactor intended for applied purposes

International Nuclear Information System (INIS)

Abramidze, Sh.P.; Katamadze, N.M.; Kiknadze, G.G.; Rostomashvili, Z.I.; Saralidze, Z.K.

2002-01-01

Nearly 50 years have passed since the appearance of the first nuclear research reactors. Most of them have completed their operating life and must be dismantled. But it is known that the dismantling of permanently shut down nuclear reactors is a very complex process, full realization that it generates a lot of radioactive waste (both solid and liquid), it is connected with high financial expenditures, and its solution is apparently beyond the possibilities of many countries, including Georgia In the given paper we consider a radiologically safe, ecologically clean and economically beneficial version of the decommissioning of the IRT-M nuclear research reactor and the stages of its implementation that are not connected with the dismantling of its highly radioactive technological components. We justify the possibility of creating a new Low Power Nuclear Facility on the basis of the decommissioned IRT-M reactor to solve the problems of applied nature in different fields of science and technology being very important for Georgia. (author)

The effect of salt composition on reductive extraction of some typical elements from molten LiF-BeF2 salt into liquid bismuth

International Nuclear Information System (INIS)

Hirotake, M.; Jun, O.; Kimikazu, M.; Kunimitsu, Y.; Yasunobu, T.

1983-01-01

The distribution coefficients of thorium and radium between molten LiF-BeF 2 and liquid bismuth solutions were measured at 600 0 C in support of the processing of the molten-salt breeder reactor (MSBR) fuel. The increasing mole fraction of LiF in the salt phase from 40 to 70 mol% resulted in the rapid decrease of the distribution coefficient of thorium and in the slow decrease of that of radium. A comprehensive correlation of distribution behavior with salt composition is given by taking into account the formation of complex ions. The equilibrium distribution data affirm that thorium and radium exist mainly as Li 2 ThF 6 and RaF 2 , respectively, in the salt phase. It is suggested that the lower mole fraction of LiF in the fuel salt is effective in the MSBR fuel processing

Display of rotational levels near the fission threshold in 232Th(n,f) reaction

International Nuclear Information System (INIS)

Blons, J.; Mazur, C.; Paya, D.

1975-01-01

The 232 Th(n,f) cross section has been measured relative to that of 235 U up to 5MeV, with a neutron energy resolution of 3keV at 1.6MeV. The angular anisotropy of fission fragments has also been measured in the same energy range with an energy resolution of 6keV at 1,6MeV. The broad vibrational levels located above 1MeV are resolved into sharp structures which are interpreted as rotational states. The rotational constants h 2 /2J of highly deformed 233 Th are found to be 2.45 and 2.65keV at 1.5 and 1.6MeV respectively. These results are interpreted by the possibility of a third minimum in the fission barrier [fr

Ionic debye screening in dense liquid plasmas observed for Li+p, d reactions with liquid Li target

International Nuclear Information System (INIS)

Kasagi, J.; Yonemura, H.; Toriyabe, Y.; Nakagawa, A.; Sugawara, T.; Wang Tieshan

2009-01-01

Thick target yields of α particles emitted in the 6 Li(d,α) 4 He and 7 Li(p,α) 4 He reactions were measured for Li target in the solid and liquid phase. Observed reaction rates for the liquid Li are always larger than those for the solid. This suggests that the stopping power of hydrogen ion in the liquid Li metal might be smaller than in the solid. Using the empirically obtained stopping power for the liquid Li, we have deduced the screening potentials of the Li+p and Li+d reactions in both phases. The deduced screening potential for the liquid Li is about 500 eV larger than for the solid. This difference is attributed to the effect of liquefied Li + ions. It is concluded that the ionic screening is much stronger than the electronic screening in a low-temperature dense plasmas. (authors)

Ionic Debye Screening in Dense Liquid Plasmas Observed for Li+p,d Reactions with Liquid Li Target

Institute of Scientific and Technical Information of China (English)

J.Kasagi; H.Yonemura; Y.Toriyabe; A.Nakagawa; T.Sugawara; WANG Tie-shan

2009-01-01

Thick target yields of a particles emitted in the ~6Li(d,a)~4 He and ~7Li(p,a)~4 He reactions were measured for Li target in the solid and liquid phase.Observed reaction rates for the liquid Li are always larger than those for the solid.This suggests that the stopping power of hydrogen ion in the liquid Li metal might be smaller than in the solid.Using the empirically obtained stopping power for the liquid Li,we have deduced the screening potentials of the Li+p and Li+d reactions in both phases.The deduced screening potential for the liquid Li is about 500 eV larger than for the solid.This difference is attributed to the effect of liquefied Li~+ ions.It is concluded that the ionic screening is much stronger than the electronic screening in a low-temperature dense plasmas.

Sputtering graphite coating to improve the elevated-temperature cycling ability of the LiMn2O4 electrode.

Science.gov (United States)

Wang, Jiexi; Zhang, Qiaobao; Li, Xinhai; Wang, Zhixing; Guo, Huajun; Xu, Daguo; Zhang, Kaili

2014-08-14

To improve the cycle performance of LiMn2O4 at elevated temperature, a graphite layer is introduced to directly cover the surface of a commercial LiMn2O4-based electrode via room-temperature DC magnetron sputtering. The as-modified cathodes display improved capacity retention as compared to the bare LiMn2O4 cathode (BLMO) at 55 °C. When sputtering graphite for 30 min, the sample shows the best cycling performance at 55 °C, maintaining 96.2% capacity retention after 200 cycles. Reasons with respect to the graphite layer for improving the elevated-temperature performance of LiMn2O4 are systematically investigated via the methods of cyclic voltammetry, electrochemical impedance spectroscopy, X-ray photoelectron spectrometry, scanning and transmission electron microscopy, X-ray diffraction and inductively coupled plasma-atomic emission spectrometry. The results demonstrate that the graphite coated LiMn2O4 cathode has much less increased electrode polarization and electrochemical impedance than BLMO during the elevated-temperature cycling process. Furthermore, the graphite layer is able to alleviate the severe dissolution of manganese ions into the electrolyte and mitigate the morphological and structural degradation of LiMn2O4 during cycling. A model for the electrochemical kinetics process is also suggested for explaining the roles of the graphite layer in suppressing the Mn dissolution.

Mass distributions in monoenergetic-neutron-induced fission of 232Th

International Nuclear Information System (INIS)

Glendenin, L.E.; Gindler, J.E.; Ahmad, I.; Henderson, D.J.; Meadows, J.W.

1980-01-01

Fission product yields for 38 masses were determined for the fission of 232 Th with essentially monoenergetic neutrons of 2.0, 3.0, 4.0, 5.9, 6.4, 6.9, 7.6, and 8.0 MeV. Fission product activities were measured by Ge(Li) γ-ray spectrometry of irradiated 232 Th foils and by chemical separation of the fission product elements followed by β counting. The mass yield data for 232 Th(n,f ) show a sensitive increase of fission yields in the near-symmetric mass region (valley) with increasing incident neutron energy E/sub n/ and a pronounced dip in yield at the onset of second-chance fission just above the neutron binding energy (at approx. 6 MeV) where the excitation energy is lowered by competition with neutron evaporation prior to fission. The effect of second-chance fission is also seen in the yields of asymmetric peak products. A distinct third peak is observed at symmetry in the valley of the mass distribution, and enhanced yields are observed in the asymmetric peaks at masses associated with even Z (proton pairing effect). The fission yeilds of 232 Th(n,f ) are compared with those of 238 U(n,f ) and 232 Th

Investigation of the $^{8}$Li($^{2}$H,p)$^{9}$Li Reaction at REX-ISOLDE

CERN Multimedia

2002-01-01

We propose to investigate the $^{8}$Li($^{2}$H,p )$^{9}$Li reaction at REX-ISOLDE. The main aim is to test a recently found discrepancy in extracted spectroscopic factors for this reaction. As a byproduct we will obtain improved data relevant for predictions of the $^{8}$Li(n,$\\gamma$)$^{9}$Li rate in inhomogeneous nucleosynthesis. For the full experiment including beam tuning and background measurements we ask for 13 shifts.

Relaxation-Induced Memory Effect of LiFePO4 Electrodes in Li-Ion Batteries.

Science.gov (United States)

Jia, Jianfeng; Tan, Chuhao; Liu, Mengchuang; Li, De; Chen, Yong

2017-07-26

In Li-ion batteries, memory effect has been found in several commercial two-phase materials as a voltage bump and a step in the (dis)charging plateau, which delays the two-phase transition and influences the estimation of the state of charge. Although memory effect has been first discovered in olivine LiFePO 4 , the origination and dependence are still not clear and are critical for regulating the memory effect of LiFePO 4 . Herein, LiFePO 4 has been synthesized by a home-built spray drying instrument, of which the memory effect has been investigated in Li-ion batteries. For as-synthesized LiFePO 4 , the memory effect is significantly dependent on the relaxation time after phase transition. Besides, the voltage bump of memory effect is actually a delayed voltage overshooting that is overlaid at the edge of stepped (dis)charging plateau. Furthermore, we studied the kinetics of LiFePO 4 electrode with electrochemical impedance spectroscopy (EIS), which shows that the memory effect is related to the electrochemical kinetics. Thereby, the underlying mechanism has been revealed in memory effect, which would guide us to optimize two-phase electrode materials and improve Li-ion battery management systems.

Ninth degree polynomial fit function for calculation of efficiency calibrations for Ge(Li) and HPGe detectors

International Nuclear Information System (INIS)

Uosif, M.A.M.

2006-01-01

A new 9 th degree polynomial fit function has been constructed to calculate the absolute γ-ray detection efficiencies (ηth) of Ge(Li) and HPGe Detectors, for calculating the absolute efficiency at any interesting γ-energy in the energy range between 25 and 2000 keV and distance between 6 and 148 cm. The total absolute γ -ray detection efficiencies have been calculated for six detectors, three of them are Ge(Li) and three HPGe at different distances. The absolute efficiency of the different detectors was calculated at the specific energy of the standard sources for each measuring distances. In this calculation, experimental (η e xp) and fitting (η f it) efficiency have been calculated. Seven calibrated point sources Am-241, Ba-133, Co-57, Co-60, Cs-137, Eu-152 and Ra-226 were used. The uncertainties of efficiency calibration have been calculated also for quality control. The measured (η e xp) and (η f it) calculated efficiency values were compared with efficiency, which calculated, by Gray fit function (time)- The results obtained on the basis of (η e xp)and (η f it) seem to be in very good agreement

Solid state opto-impedance of LiNiVO4 and LiMn2O4

International Nuclear Information System (INIS)

Kalyani, P; Sivasubramanian, S; Prabhu, S Naveen; Ragavendran, K; Kalaiselvi, N; Ranganathan, N G; Madhu, S; SundaraRaj, A; Manoharan, S P; Jagannathan, R

2005-01-01

Spinel type LiMn 2 O 4 and inverse spinel LiNiVO 4 systems serve as standard cathode materials or potential cathode systems for application in high energy density lithium-ion batteries. Upon photo-excitation using UV radiation of energy ∼5 eV, the LiNiVO 4 system shows significant modification in the solid state impedance pattern while the LiMn 2 O 4 system does not. This study has revealed a significant difference in the opto-impedance pattern for LiNiVO 4 with respect to LiMn 2 O 4 , which may be due to the different electronic processes involved. An attempt has been made to study this behaviour from the solid-state viewpoint

Molecular evolution of the Li/li chemical defence polymorphism in white clover (Trifolium repens L.).

Science.gov (United States)

Olsen, K M; Sutherland, B L; Small, L L

2007-10-01

White clover (Trifolium repens) is naturally polymorphic for cyanogenesis (hydrogen cyanide release following tissue damage). The ecological factors favouring cyanogenic and acyanogenic plants have been examined in numerous studies over the last half century, making this one of the best-documented examples of an adaptive polymorphism in plants. White clover cyanogenesis is controlled by two, independently segregating Mendelian genes: Ac/ac controls the presence/absence of cyanogenic glucosides; and Li/li controls the presence/absence of their hydrolysing enzyme, linamarase. In this study, we examine the molecular evolution and population genetics of Li as it relates to the cyanogenesis polymorphism. We report here that Li exists as a single-copy gene in plants possessing linamarase activity, and that the absence of enzyme activity in li/li plants is correlated with the absence of much or all of the gene from the white clover genome. Consistent with this finding, we confirm by reverse transcription-polymerase chain reaction that Li gene expression is absent in plants lacking enzyme activity. In a molecular population genetic analysis of Li and three unlinked genes using a worldwide sample of clover plants, we find an absence of nucleotide variation and statistically significant deviations from neutrality at Li; these findings are consistent with recent positive directional selection at this cyanogenesis locus.

Al-Cu-Li and Al-Mg-Li alloys: Phase composition, texture, and anisotropy of mechanical properties (Review)

Science.gov (United States)

Betsofen, S. Ya.; Antipov, V. V.; Knyazev, M. I.

2016-04-01

The results of studying the phase transformations, the texture formation, and the anisotropy of the mechanical properties in Al-Cu-Li and Al-Mg-Li alloys are generalized. A technique and equations are developed to calculate the amounts of the S1 (Al2MgLi), T1 (Al2CuLi), and δ' (Al3Li) phases. The fraction of the δ' phase in Al-Cu-Li alloys is shown to be significantly higher than in Al-Mg-Li alloys. Therefore, the role of the T1 phase in the hardening of Al-Cu-Li alloys is thought to be overestimated, especially in alloys with more than 1.5% Li. A new model is proposed to describe the hardening of Al-Cu-Li alloys upon aging, and the results obtained with this model agree well with the experimental data. A texture, which is analogous to that in aluminum alloys, is shown to form in sheets semiproducts made of Al-Cu-Li and Al-Mg-Li alloys. The more pronounced anisotropy of the properties of lithium-containing aluminum alloys is caused by a significant fraction of the ordered coherent δ' phase, the deformation mechanism in which differs radically from that in the solid solution.

Preparation of Ce- and La-Doped Li4Ti5O12 Nanosheets and Their Electrochemical Performance in Li Half Cell and Li4Ti5O12/LiFePO4 Full Cell Batteries

Directory of Open Access Journals (Sweden)

Meng Qin

2017-06-01

Full Text Available This work reports on the synthesis of rare earth-doped Li4Ti5O12 nanosheets with high electrochemical performance as anode material both in Li half and Li4Ti5O12/LiFePO4 full cell batteries. Through the combination of decreasing the particle size and doping by rare earth atoms (Ce and La, Ce and La doped Li4Ti5O12 nanosheets show the excellent electrochemical performance in terms of high specific capacity, good cycling stability and excellent rate performance in half cells. Notably, the Ce-doped Li4Ti5O12 shows good electrochemical performance as anode in a full cell which LiFePO4 was used as cathode. The superior electrochemical performance can be attributed to doping as well as the nanosized particle, which facilitates transportation of the lithium ion and electron transportation. This research shows that the rare earth doped Li4Ti5O12 nanosheets can be suitable as a high rate performance anode material in lithium-ion batteries.

Preparation of Ce- and La-Doped Li4Ti5O12 Nanosheets and Their Electrochemical Performance in Li Half Cell and Li4Ti5O12/LiFePO4 Full Cell Batteries

Science.gov (United States)

Qin, Meng; Li, Yueming; Lv, Xiao-Jun

2017-01-01

This work reports on the synthesis of rare earth-doped Li4Ti5O12 nanosheets with high electrochemical performance as anode material both in Li half and Li4Ti5O12/LiFePO4 full cell batteries. Through the combination of decreasing the particle size and doping by rare earth atoms (Ce and La), Ce and La doped Li4Ti5O12 nanosheets show the excellent electrochemical performance in terms of high specific capacity, good cycling stability and excellent rate performance in half cells. Notably, the Ce-doped Li4Ti5O12 shows good electrochemical performance as anode in a full cell which LiFePO4 was used as cathode. The superior electrochemical performance can be attributed to doping as well as the nanosized particle, which facilitates transportation of the lithium ion and electron transportation. This research shows that the rare earth doped Li4Ti5O12 nanosheets can be suitable as a high rate performance anode material in lithium-ion batteries. PMID:28632167

Nano-sized LiFePO4/C composite with core-shell structure as cathode material for lithium ion battery

International Nuclear Information System (INIS)

Liu, Yang; Zhang, Min; Li, Ying; Hu, Yemin; Zhu, Mingyuan; Jin, Hongming; Li, Wenxian

2015-01-01

Graphical abstract: Nano-sized LiFePO4/C composite with core-shell structure was fabricated via a well-designed approach as cathode material forlithium ion battery. The nano-sized LiFePO4/C composite with whole carbon shell coating layer showed an excellent electrical performance. - Abstract: Nano-sized composite with LiFePO 4 -core and carbon-shell was synthesized via a facile route followed by heat treatment at 650 °C. X-ray diffraction (XRD) shows that the core is well crystallized LiFePO 4 . The electron microscopy (SEM and TEM) observations show that the core-shell structured LiFePO 4 /C composite coating with whole carbon shell layer of ∼2.8 nm, possesses a specific surface area of 51 m 2 g −1 . As cathode material for lithium ion battery, the core-shell LiFePO 4 /C composite exhibits high initial capacity of 161 mAh g −1 at 0.1 C, excellent high-rate discharge capacity of 135 mAh g −1 at 5 C and perfect cycling retention of 99.6% at 100 th cycle. All these promising results should be contributed to the core-shell nanostructure which prevents collapse of the particle structure in the long-term charge and discharge cycles, as well as the large surface area of the nano-sized LiFePO 4 /C composite which enhances the electronic conductivity and shortens the distance of lithium ion diffusion

Silver effect of Co–Ni composite material on energy storage and structural behavior for Li-ion batteries

International Nuclear Information System (INIS)

Gnanamuthu, RM.; Prasanna, K.; Subburaj, T.; Jo, Yong Nam; Lee, Chang Woo

2013-01-01

Ag powder has been comparatively applied to the Co–Ni materials preparing by mixing method and the prepared electrodes were used as negative electrodes for Li-ion batteries applications. The prepared Co–Ni and Ag–Co–Ni with 10 wt.% of Ag composite electrodes are characterized by XRD, FE-SEM with EDX, impedance and electrochemical charge-discharge studies. These electrochemical studies are demonstrated at current rates of 0.1 C and 0.5 C between 0.01 and 2.0 V vs. Li/Li + . The porous Co–Ni and Ag–Co–Ni composite materials are electrochemically tested in lithium half cells. The porous Ag–Co–Ni composite material demonstrates that the initial and end of discharge capacity up to 20th cycles is, respectively, 860 and 715 mAh g −1 at 0.1 C rate maintaining at approximately 83%. The porous Ag–Co–Ni composite electrode may be a good candidate for high power lithium-ion batteries.

Synthesis, Structure, and Li-Ion Conductivity of LiLa(BH4)3X, X = Cl, Br, I

DEFF Research Database (Denmark)

Payandeh GharibDoust, SeyedHosein; Brighi, Matteo; Sadikin, Yolanda

2017-01-01

In this work, a new type of addition reaction between La(BH4)3 and LiX, X = Cl, Br, I, is used to synthesize LiLa(BH4)3Cl and two new compounds LiLa(BH4)3X, X = Br, I. This method increases the amounts of LiLa(BH4)3X and the sample purity. The highest Li-ion conductivity is observed for LiLa(BH4)...

14th Annual Small Business Conference

Science.gov (United States)

2010-11-18

Government Contracting, Small Business Administration 5:45 pm - 7:45 pm RECEPTION IN DISPLAY AREA 14TH ANNUAL SMALL BUSINESS CONFERENCE...as a lobbyist for a large multi-national conglomerate that included among its subsidiaries movie companies, sports teams, financial services companies...Past Performance /Small Business Participation > M.1 Basis of Award: The Government plans to award a single contract for the Fighting Trailer

2013 Puget Sound LiDAR Consortium (PSLC) Topographic LiDAR: Nooksack

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — In July 2012, WSI (Watershed Sciences, Inc.) was contracted by the Puget Sound LiDARConsortium (PSLC) to collect Light Detection and Ranging (LiDAR) data on a...

2013 Puget Sound LiDAR Consortium (PSLC) Topographic LiDAR: Entiat

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — In October 2012, WSI (Watershed Sciences, Inc.) was contracted by the Puget Sound LiDARConsortium (PSLC) to collect Light Detection and Ranging (LiDAR) data for the...

Enhanced Li-Ion Battery

Directory of Open Access Journals (Sweden)

Natasha Ross

2015-01-01

Full Text Available Au with Pd nanoparticles were synthesized and coated onto the spinel LiMn2O4 via a coprecipitation calcination method with the objective to improve the microstructure, conductivity, and electrochemical activities of pristine LiMn2O4. The novel LiPdAuxMn2-xO4 composite cathode had high phase purity, well crystallized particles, and more regular morphological structures with narrow size distributions. At enlarged cycling potential ranges the LiPdAuxMn2-xO4 sample delivered 90 mAh g−1 discharge capacity compared to LiMn2O4 (45 mAh g−1. It was concluded that even a small amount of the Pd and Au enhanced both the lithium diffusivity and electrochemical conductivity of the host sample due to the beneficial properties of their synergy.

Epitaxial thin film growth of LiH using a liquid-Li atomic template

Energy Technology Data Exchange (ETDEWEB)

Oguchi, Hiroyuki, E-mail: oguchi@nanosys.mech.tohoku.ac.jp [Department of Nanomechanics, Tohoku University, Sendai 980-8579 (Japan); Micro System Integration Center (muSIC), Tohoku University, Sendai 980-0845 (Japan); Ikeshoji, Tamio; Orimo, Shin-ichi [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai 980-8577 (Japan); Ohsawa, Takeo; Shiraki, Susumu; Hitosugi, Taro [Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai 980-8577 (Japan); Kuwano, Hiroki [Department of Nanomechanics, Tohoku University, Sendai 980-8579 (Japan)

2014-11-24

We report on the synthesis of lithium hydride (LiH) epitaxial thin films through the hydrogenation of a Li melt, forming abrupt LiH/MgO interface. Experimental and first-principles molecular dynamics studies reveal a comprehensive microscopic picture of the crystallization processes, which sheds light on the fundamental atomistic growth processes that have remained unknown in the vapor-liquid-solid method. We found that the periodic structure that formed, because of the liquid-Li atoms at the film/MgO-substrate interface, serves as an atomic template for the epitaxial growth of LiH crystals. In contrast, films grown on the Al{sub 2}O{sub 3} substrates indicated polycrystalline films with a LiAlO{sub 2} secondary phase. These results and the proposed growth process provide insights into the preparation of other alkaline metal hydride thin films on oxides. Further, our investigations open the way to explore fundamental physics and chemistry of metal hydrides including possible phenomena that emerge at the heterointerfaces of metal hydrides.

Rate-dependent, Li-ion insertion/deinsertion behavior of LiFePO4 cathodes in commercial 18650 LiFePO4 cells.

Science.gov (United States)

Liu, Qi; He, Hao; Li, Zhe-Fei; Liu, Yadong; Ren, Yang; Lu, Wenquan; Lu, Jun; Stach, Eric A; Xie, Jian

2014-03-12

We have performed operando synchrotron high-energy X-ray diffraction (XRD) to obtain nonintrusive, real-time monitoring of the dynamic chemical and structural changes in commercial 18650 LiFePO4/C cells under realistic cycling conditions. The results indicate a nonequilibrium lithium insertion and extraction in the LiFePO4 cathode, with neither the LiFePO4 phase nor the FePO4 phase maintaining a static composition during lithium insertion/extraction. On the basis of our observations, we propose that the LiFePO4 cathode simultaneously experiences both a two-phase reaction mechanism and a dual-phase solid-solution reaction mechanism over the entire range of the flat voltage plateau, with this dual-phase solid-solution behavior being strongly dependent on charge/discharge rates. The proposed dual-phase solid-solution mechanism may explain the remarkable rate capability of LiFePO4 in commercial cells.

A new, high energy rechargeable lithium ion battery with a surface-treated Li1.2Mn0.54Ni0.13Co0.13O2 cathode and a nano-structured Li4Ti5O12 anode

International Nuclear Information System (INIS)

Liu, Xiaoyu; Huang, Tao; Yu, Aishui

2015-01-01

Through elaborate design, a new rechargeable lithium ion battery has been developed by comprising a surface-treated Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode and a nano-structured Li 4 Ti 5 O 12 anode. After precondition Na 2 S 2 O 8 treatment, the initial coulombic efficiency of Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode has been significantly increased and can be compatible with that of the nano-structured Li 4 Ti 5 O 12 anode. The optimization of structure and morphology for both active electrode materials result in their remarkable electrochemical performances in respective lithium half-cells. Ultimately, the rechargeable lithium ion full battery consisting of both electrodes delivers a specific capacity of 99.0 mAh g −1 and a practical energy density of 201 Wh kg −1 , based on the total weight of both active electrode materials. Furthermore, as a promising candidate in the lithium ion battery field, this full battery also achieves highly attractive electrochemical performance with high coulombic efficiency, excellent cycling stability and outstanding rate capability. Thus the proposed battery displays broad practical application prospects for next generation of high-energy lithium ion battery. - Highlights: • The Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode is surface-treated by Na 2 S 2 O 8 . • The nano-sized Li 4 Ti 5 O 12 anode is obtained by a solid-state method. • A new Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 /Li 4 Ti 5 O 12 lithium ion battery is developed. • The battery shows high coulombic efficiency, specific capacity and energy density. • The battery shows high capacity retention rate and good high-rate capability

Electronic Stopping Power in LiF from First Principles

International Nuclear Information System (INIS)

Pruneda, J. M.; Sanchez-Portal, D.; Arnau, A.; Juaristi, J. I.; Artacho, Emilio

2007-01-01

Using time-dependent density-functional theory we calculate from first principles the rate of energy transfer from a moving proton or antiproton to the electrons of an insulating material, LiF. The behavior of the electronic stopping power versus projectile velocity displays an effective threshold velocity of ∼0.2 a.u. for the proton, consistent with recent experimental observations, and also for the antiproton. The calculated proton/antiproton stopping-power ratio is ∼2.4 at velocities slightly above the threshold (v∼0.4 a.u.), as compared to the experimental value of 2.1. The projectile energy loss mechanism is observed to be extremely local

Experiments on iron shield transmission of quasi-monoenergetic neutrons generated by 43- and 68-MeV protons via the 7Li(p,n) reaction

International Nuclear Information System (INIS)

Nakashima, Hiroshi; Tanaka, Shun-ichi; Nakao, Noriaki

1996-03-01

In order to provide benchmark data of neutrons transmitted through iron shields in the intermediate-energy region, spatial distributions of neutron energy spectra and reaction rates behind and inside the iron shields of thickness up to 130 cm were measured for 43- and 68-MeVp- 7 Li neutrons using a quasi-monoenergetic neutron beam source at the 90-MV AVF cyclotron facility of the TLARA facility in JAERI. The measured data by five kinds of detectors: the BC501A detector, the Bonner ball counter, 238 U and 232 Th fission counters, 7 LiF and nat LiF TLDs and solid state nuclear track detector, are numerically provided in this report in the energy region between 10 -4 eV and the energy of peak neutrons generated by the 7 Li(p,n) reaction. (author)

Improvement on high rate performance of LiFePO4 cathodes using graphene as a conductive agent

Science.gov (United States)

Wei, Xufang; Guan, Yibiao; Zheng, Xiaohui; Zhu, Qizhen; Shen, Jinran; Qiao, Ning; Zhou, Shuqin; Xu, Bin

2018-05-01

In this work, the electrochemical properties of the LiFePO4 cathode using graphene as a conductive agent were revealed. Compared to the conventional LiFePO4 electrodes with carbon black as a conductive agent, the graphene sheets can establish a more effective conductive framework due to their layered structure and excellent electronic conductivity, leading to better electrochemical rate performance. Furthermore, the obverse of increasing graphene content is continued gains in high-rate performance of the LiFePO4 electrodes. The electrodes with 30 wt% graphene show high capacities up to 103.1 mA h g-1 and 68 mA h g-1 during discharging with extremely high rates of 30 C and 50 C, respectively. Besides, good cycling performance at high rate is also achieved. The electrodes with 30 wt% graphene display a capacity retention higher than 80% after 1000 cycles at 30 C. These results not only indicate that the graphene could be a promising candidate as a conductive agent, but also provide a new insight for designing LiFePO4 electrodes with brilliant high-rate performance via a simple method.

Synthesis and structural stability of Cr-doped Li2MnSiO4/C cathode materials by solid-state method

Science.gov (United States)

Cheng, Hong-Mei; Zhao, Shi-Xi; Wu, Xia; Zhao, Jian-Wei; Wei, Lei; Nan, Ce-Wen

2018-03-01

The crystal structure of the Li2MnSiO4 cathode material would collapse during the charge and discharge process because of that the Mn-O coordination polyhedron changed from [MnO4] into [MnO6] in the process of Mn+2 to Mn+4, but the Cr element could remain [CrO4] crystal ligand from Cr+2 to Cr+4, so Cr element substitution was used to improve the structural stability of the Li2MnSiO4 cathode material. In this work, Li2Mn1-xCrxSiO4/C nanocomposites were synthesized by solid-state method. XRD, SEM and TEM observations show that the as-prepared Li2Mn1-xCrxSiO4/C materials presents an orthorhombic crystal structure (S.G. Pmn21), the particle size of Li2Mn1-xCrxSiO4/C powder ranges from 50 to 100 nm. The XRD and XPS results indicate that Cr+2 is successfully doped into Li2MnSiO4 lattice and has well compatibility with Li2MnSiO4. The electrochemical results display that Li2Mn92.5%Cr7.5%SiO4/C exhibits significantly enhanced cycle stability and discharge capability. The initial discharge capacity of the Li2Mn92.5%Cr7.5%SiO4/C sample is 255 mAh g-1, and the discharge capacity was still about 60 mAh g-1 after 50 cycles. Furthermore, the XRD patterns, TEM images and Raman analysis reveal that the Cr doping enhances the structural stability of Li2Mn1-xCrxSiO4/C and improves the electrochemical activity of the cathode. Thus, the Li2Mn92.5%Cr7.5%SiO4/C have shown potential applications for lithium ion batteries.

Th1 and Th17 Cells and Associated Cytokines Discriminate among Clinically Isolated Syndrome and Multiple Sclerosis Phenotypes.

Science.gov (United States)

Arellano, Gabriel; Acuña, Eric; Reyes, Lilian I; Ottum, Payton A; De Sarno, Patrizia; Villarroel, Luis; Ciampi, Ethel; Uribe-San Martín, Reinaldo; Cárcamo, Claudia; Naves, Rodrigo

2017-01-01

Multiple sclerosis (MS) is a chronic, inflammatory, and demyelinating disease of the central nervous system. It is a heterogeneous pathology that can follow different clinical courses, and the mechanisms that underlie the progression of the immune response across MS subtypes remain incompletely understood. Here, we aimed to determine differences in the immunological status among different MS clinical subtypes. Blood samples from untreated patients diagnosed with clinically isolated syndrome (CIS) ( n  = 21), different clinical forms of MS ( n  = 62) [relapsing-remitting (RRMS), secondary progressive, and primary progressive], and healthy controls (HCs) ( n  = 17) were tested for plasma levels of interferon (IFN)-γ, IL-10, TGF-β, IL-17A, and IL-17F by immunoanalysis. Th1 and Th17 lymphocyte frequencies were determined by flow cytometry. Our results showed that IFN-γ levels and the IFN-γ/IL-10 ratio were higher in CIS patients than in RRMS patients and HC. Th1 cell frequencies were higher in CIS and RRMS than in progressive MS, and RRMS had a higher Th17 frequency than CIS. The Th1/Th17 cell ratio was skewed toward Th1 in CIS compared to MS phenotypes and HC. Receiver operating characteristic statistical analysis determined that IFN-γ, the IFN-γ/IL-10 ratio, Th1 cell frequency, and the Th1/Th17 cell ratio discriminated among CIS and MS subtypes. A subanalysis among patients expressing high IL-17F levels showed that IL-17F and the IFN-γ/IL-17F ratio discriminated between disease subtypes. Overall, our data showed that CIS and MS phenotypes displayed distinct Th1- and Th17-related cytokines and cell profiles and that these immune parameters discriminated between clinical forms. Upon validation, these parameters might be useful as biomarkers to predict disease progression.

Residual Salt Separation from the Metal Products Reduced in a LiCl-Li{sub 2}O Molten Salt

Energy Technology Data Exchange (ETDEWEB)

Hur, Jin Mok; Hong, Sun Seok; Kang, Dae Seung; Jeong, Meong Soo; Seo, Chung Seok

2006-02-15

The electrochemical reduction of spent nuclear fuel in a LiCl-Li{sub 2}O molten salt for the conditioning of spent nuclear fuel requires the separation of the residual salts from a reduced metal product after the reduction process. Considering the behavior of spent nuclear fuel during the electrochemical reduction process, a surrogate material matrix was constructed and inactive tests on a salt separation were carried out to produce the data required for the active tests. Fresh uranium metal prepared from the electrochemical reduction of U{sub 3}O{sub 8} powder was used as the surrogates of the spent nuclear fuel components which might be metallized by the electrochemical reduction process. LiCl, Li{sub 2}O, Y{sub 2}O{sub 3} and SrCl{sub 2} were selected as the components of the residual salts. Interactions between the salts and their influence on the separation of the residual salts were analyzed by differential scanning calorimetry (DSC) and thermogravimetry (TG). Eutectic melting of LiCl-Li{sub 2}O and LiCl-SrCl{sub 2} led to a melting point which was lower than that of a LiCl molten salt was observed. Residual salts were separated by a vaporization method. Co-vaporization of LiCl-Li{sub 2}O and LiCl-SrCl{sub 2} was achieved below temperatures which could make the uranium metal oxidation by Li{sub 2}O possible. The salt vaporization rates at 950 .deg. C were measured as follows: LiCl-8 wt% Li{sub 2}O > LiCl > LiCl-8 wt% SrCl{sub 2} > SrCl{sub 2}.

Synthesis of graphene supported Li2SiO3 as a high performance anode material for lithium-ion batteries

Science.gov (United States)

Yang, Shuai; Wang, Qiufen; Miao, Juan; Zhang, Jingyang; Zhang, Dafeng; Chen, Yumei; Yang, Hong

2018-06-01

The Li2SiO3-graphene composite is successfully synthesized through an easy hydrothermal method. The structures and morphologies of the produced samples are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectrum, Brunauer-Emmett-Teller formalism, scanning electron microscope, transmission electron microscope, and electrochemistry methods. The result shows a well crystalline of the Li2SiO3-GE composite. The existence of graphene doesn't change the crystalline of Li2SiO3. In addition, the Li2SiO3 compound with an average diameter of 20 nm can be seen on the surface of graphene with uniform distribution. After the composite with graphene, the composite displays large surface area which ensures the well electrochemistry of the composite. Finally, the Li2SiO3-graphene composite delivers a high initial capacity of 878.3 mAh g-1 at 1C as well as a high recovery capacity of 400 mAh g-1 after 200 cycles. When charged and discharged at high rate, the Li2SiO3-doping graphene composite still exhibits a high specific capacity of 748.3 mAh g-1 (at 2C, and 576 mAh g-1 at 5C) and well cycling performance. The well synthesized composite possesses well structure and well electrochemistry performance.

Design and operation of thermal-convection loops for corrosion measurements in LiF--LiCl--LiBr

International Nuclear Information System (INIS)

Keiser, J.R.; DeVan, J.H.

1979-01-01

Using a most sophisticated design of a thermal-convection loop to study the corrosion behavior of type 316 stainless steel and the salt mixture LiF--LiCl--LiBr is reported. The corrosion rate is being determined as a function of time and temperature through weight change measurements. The maximum corrosion rate measured is about 20 μm/year on removable corrosion specimens. Controlled potential voltammetry has been found to be satisfactory and is being used to monitor the oxidation potential of the salt. Measurements demonstrate the effect on the oxidation potential of impurities introduced during specimen insertion, and techniques should show the effect of a lithium addition on the oxidation potential

Li2 NH-LiBH4 : a Complex Hydride with Near Ambient Hydrogen Adsorption and Fast Lithium Ion Conduction.

Science.gov (United States)

Wang, Han; Cao, Hujun; Zhang, Weijin; Chen, Jian; Wu, Hui; Pistidda, Claudio; Ju, Xiaohua; Zhou, Wei; Wu, Guotao; Etter, Martin; Klassen, Thomas; Dornheim, Martin; Chen, Ping

2018-01-26

Complex hydrides have played important roles in energy storage area. Here a complex hydride made of Li 2 NH and LiBH 4 was synthesized, which has a structure tentatively indexed using an orthorhombic cell with a space group of Pna2 1 and lattice parameters of a=10.121, b=6.997, and c=11.457 Å. The Li 2 NH-LiBH 4 sample (in a molar ratio of 1:1) shows excellent hydrogenation kinetics, starting to absorb H 2 at 310 K, which is more than 100 K lower than that of pristine Li 2 NH. Furthermore, the Li + ion conductivity of the Li 2 NH-LiBH 4 sample is about 1.0×10 -5  S cm -1 at room temperature, and is higher than that of either Li 2 NH or LiBH 4 at 373 K. Those unique properties of the Li 2 NH-LiBH 4 complex render it a promising candidate for hydrogen storage and Li ion conduction. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interaction between U and Th on their uptake, distribution, and toxicity in V S. alfredii based on the phytoremediation of U and Th.

Science.gov (United States)

Huang, Zhenling; Tang, Siqun; Zhang, Lu; Ma, Lijian; Ding, Songdong; Du, Liang; Zhang, Dong; Jin, Yongdong; Wang, Ruibing; Huang, Chao; Xia, Chuanqin

2017-01-01

Variant Sedum alfredii Hance (V S. alfredii) could simultaneously take up U and Th from water with the highest concentrations recorded as 1.84 × 10 4 and 6.72 × 10 3  mg/kg in the roots, respectively. Th stimulated U uptake by V S. alfredii roots at Th 10 (10 μM of Th), however, the opposite was observed at Th 100 (100 μM of Th). A similar result was found in the effect of U on the uptake of Th by V S. alfredii. Subcellular fractionation studies of V S. alfredii indicated that U and Th were mainly stored in cell wall fraction, and much less was found in organelle and soluble fractions. Chemical form examination results showed that water-soluble U and Th were the predominant chemical forms in this plant. Addition of the other radionuclide in aqueous solutions altered the concentration and percentage of U or Th in cell wall fraction and in water-soluble form, resulting in the change of the uptake capacity of U or Th by V S. alfredii roots. Comparing with single U or Th treatment, the plant cells revealed more swollen chloroplasts and enhanced thickening in cell walls under the U 100  + Th 100 treatment, as observed by TEM. Those results collectively displayed that V S. alfredii may be utilized as a potential plant to simultaneously remove U and Th from aqueous solutions (rhizofiltration).

Scintillation properties of LiF–SrF{sub 2} and LiF–CaF{sub 2} eutectic

Energy Technology Data Exchange (ETDEWEB)

Yanagida, Takayuki, E-mail: yanagida@lsse.kyutech.ac.jp [Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Kitakyushu 808-0196 (Japan); Kawaguchi, Noriaki [Tokuyama Corporation, 1-1 Mikage-cho, Shunan-shi, Yamaguchi 745-8648 (Japan); Fujimoto, Yutaka [Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Kitakyushu 808-0196 (Japan); Fukuda, Kentaro [Tokuyama Corporation, 1-1 Mikage-cho, Shunan-shi, Yamaguchi 745-8648 (Japan); Watanabe, Kenichi; Yamazaki, Atsushi; Uritani, Akira [Quantum Science and Energy Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

2013-12-15

Dopant free eutectic scintillators {sup 6}LiF–SrF{sub 2} and {sup 6}LiF–CaF{sub 2} were developed by the vertical Bridgeman method for the purpose of thermal neutron detection. The molar ratio of LiF and Ca/SrF{sub 2} was 4:1 on its eutectic composition. The α-ray induced radioluminescence spectra of the scintillators showed intense emission peak at 300 nm due to the emission from the self-trapped exciton in Ca/SrF{sub 2} layers. When the samples were irradiated with {sup 252}Cf neutrons, {sup 6}LiF–SrF{sub 2} and {sup 6}LiF–CaF{sub 2} exhibited the light yields of 4700 and 9400 ph/n, respectively. Scintillation decay times of {sup 6}LiF–SrF{sub 2} and {sup 6}LiF–CaF{sub 2} were accepted for scintillation detectors, 90 and 250 ns, respectively. -- Highlights: • Nondoped LiF–CaF{sub 2} and LiF–SrF{sub 2} eutectic scinitillators are reported for the first time. • Two sample showed self-trapped exciton emission. • LiF–SrF{sub 2} sample exhibited the light yield of 9400 ph/n and this value was comparable to conventional materials doped with rare earth ions. • Scintillation decay times of LiF–CaF{sub 2} and LiF–SrF{sub 2} were 250 and 90 ns, respectively.

Continuous flame aerosol synthesis of carbon-coated nano-LiFePO4 for Li-ion batteries

Science.gov (United States)

Waser, Oliver; Büchel, Robert; Hintennach, Andreas; Novák, Petr; Pratsinis, Sotiris E.

2013-01-01

Core-shell, nanosized LiFePO4-carbon particles were made in one step by scalable flame aerosol technology at 7 g/h. Core LiFePO4 particles were made in an enclosed flame spray pyrolysis (FSP) unit and were coated in-situ downstream by auto thermal carbonization (pyrolysis) of swirl-fed C2H2 in an O2-controlled atmosphere. The formation of acetylene carbon black (ACB) shell was investigated as a function of the process fuel-oxidant equivalence ratio (EQR). The core-shell morphology was obtained at slightly fuel-rich conditions (1.0 < EQR < 1.07) whereas segregated ACB and LiFePO4 particles were formed at fuel-lean conditions (0.8 < EQR < 1). Post-annealing of core-shell particles in reducing environment (5 vol% H2 in argon) at 700 °C for up to 4 hours established phase pure, monocrystalline LiFePO4 with a crystal size of 65 nm and 30 wt% ACB content. Uncoated LiFePO4 or segregated LiFePO4-ACB grew to 250 nm at these conditions. Annealing at 800 °C induced carbothermal reduction of LiFePO4 to Fe2P by ACB shell consumption that resulted in cavities between carbon shell and core LiFePO4 and even slight LiFePO4 crystal growth but better electrochemical performance. The present carbon-coated LiFePO4 showed superior cycle stability and higher rate capability than the benchmark, commercially available LiFePO4. PMID:23407817

Relevance of LiPF6 as Etching Agent of LiMnPO4 Colloidal Nanocrystals for High Rate Performing Li-ion Battery Cathodes.

Science.gov (United States)

Chen, Lin; Dilena, Enrico; Paolella, Andrea; Bertoni, Giovanni; Ansaldo, Alberto; Colombo, Massimo; Marras, Sergio; Scrosati, Bruno; Manna, Liberato; Monaco, Simone

2016-02-17

LiMnPO4 is an attractive cathode material for the next-generation high power Li-ion batteries, due to its high theoretical specific capacity (170 mA h g(-1)) and working voltage (4.1 V vs Li(+)/Li). However, two main drawbacks prevent the practical use of LiMnPO4: its low electronic conductivity and the limited lithium diffusion rate, which are responsible for the poor rate capability of the cathode. The electronic resistance is usually lowered by coating the particles with carbon, while the use of nanosize particles can alleviate the issues associated with poor ionic conductivity. It is therefore of primary importance to develop a synthetic route to LiMnPO4 nanocrystals (NCs) with controlled size and coated with a highly conductive carbon layer. We report here an effective surface etching process (using LiPF6) on colloidally synthesized LiMnPO4 NCs that makes the NCs dispersible in the aqueous glucose solution used as carbon source for the carbon coating step. Also, it is likely that the improved exposure of the NC surface to glucose facilitates the formation of a conductive carbon layer that is in intimate contact with the inorganic core, resulting in a high electronic conductivity of the electrode, as observed by us. The carbon coated etched LiMnPO4-based electrode exhibited a specific capacity of 118 mA h g(-1) at 1C, with a stable cycling performance and a capacity retention of 92% after 120 cycles at different C-rates. The delivered capacities were higher than those of electrodes based on not etched carbon coated NCs, which never exceeded 30 mA h g(-1). The rate capability here reported for the carbon coated etched LiMnPO4 nanocrystals represents an important result, taking into account that in the electrode formulation 80% wt is made of the active material and the adopted charge protocol is based on reasonable fast charge times.

76 FR 34862 - Safety Zones: Fireworks Displays in the Captain of the Port Columbia River Zone

Science.gov (United States)

2011-06-15

... p.m. until 11:30 p.m. on May 27, 2011. (2) Tri-City Chamber of Commerce Fireworks Display, Columbia... from 9 p.m. to 11 p.m. (12) Arlington Chamber of Commerce Fireworks Display, Arlington, OR: On July 4... Fireworks, Portland, OR: From 8:30 p.m. until 11:30 p.m. on July 4, 2011. (6) Florence Chamber 4th of July...

Electrochemical Characteristics and Li+ Ion Intercalation Kinetics of Dual-phase Li4Ti5O12/Li2TiO3 Composite in Voltage Range of 0−3 V

KAUST Repository

Bhatti, Humaira S

2016-04-20

Li4Ti5O12, Li2TiO3 and dual-phase Li4Ti5O12/Li2TiO3 composite were prepared by sol-gel method with average particle size of 1 µm, 0.3 µm and 0.4 µm, respectively. Though Li2TiO3 is electrochemically inactive, the rate capability of Li4Ti5O12/Li2TiO3 is comparable to Li4Ti5O12 at different current rates. Li4Ti5O12/Li2TiO3 also shows good rate performance of 90 mA h g-1 at high rate of 10 C in voltage range of 1−3 V, attributable to increased interfaces in the composite. While Li4Ti5O12 delivers capacity retention of 88.6 % at 0.2 C over 50 cycles, Li4Ti5O12/Li2TiO3 exhibits no capacity fading at 0.2 C (40 cycles) and capacity retention of 98.45 % at 0.5 C (50 cycles). This highly stable cycling performance is attributed to the contribution of Li2TiO3 in preventing undesirable reaction of Li4Ti5O12 with the electrolyte during cycling. CV curves of Li4Ti5O12/Li2TiO3 in 0−3 V range exhibit two anodic peaks at 1.51 V and 0.7−0.0 V, indicating two modes of lithium intercalation into the lattice sites of active material. Owing to enhanced intercalation/de-intercalation kinetics in 0−3 V, composite electrode delivers superior rate performance of 203 mAh/g at 2.85 C and 140 mAh/g at 5.7 C with good reversible capacity retention over 100 cycles.

Electrochemical Characteristics and Li+ Ion Intercalation Kinetics of Dual-phase Li4Ti5O12/Li2TiO3 Composite in Voltage Range of 0−3 V

KAUST Repository

Bhatti, Humaira S; Anjum, Dalaver H.; Ullah, Shafiq; Ahmed, Bilal; Habib, Amir; Karim, Altaf; Hasanain, Syed Khurshid

2016-01-01

Li4Ti5O12, Li2TiO3 and dual-phase Li4Ti5O12/Li2TiO3 composite were prepared by sol-gel method with average particle size of 1 µm, 0.3 µm and 0.4 µm, respectively. Though Li2TiO3 is electrochemically inactive, the rate capability of Li4Ti5O12/Li2TiO3 is comparable to Li4Ti5O12 at different current rates. Li4Ti5O12/Li2TiO3 also shows good rate performance of 90 mA h g-1 at high rate of 10 C in voltage range of 1−3 V, attributable to increased interfaces in the composite. While Li4Ti5O12 delivers capacity retention of 88.6 % at 0.2 C over 50 cycles, Li4Ti5O12/Li2TiO3 exhibits no capacity fading at 0.2 C (40 cycles) and capacity retention of 98.45 % at 0.5 C (50 cycles). This highly stable cycling performance is attributed to the contribution of Li2TiO3 in preventing undesirable reaction of Li4Ti5O12 with the electrolyte during cycling. CV curves of Li4Ti5O12/Li2TiO3 in 0−3 V range exhibit two anodic peaks at 1.51 V and 0.7−0.0 V, indicating two modes of lithium intercalation into the lattice sites of active material. Owing to enhanced intercalation/de-intercalation kinetics in 0−3 V, composite electrode delivers superior rate performance of 203 mAh/g at 2.85 C and 140 mAh/g at 5.7 C with good reversible capacity retention over 100 cycles.

DFT+U study of polaronic conduction in Li2O2 and Li2CO3

DEFF Research Database (Denmark)

García Lastra, Juan Maria; Myrdal, J.S.G.; Christensen, Rune

2013-01-01

The main discharge products formed at the cathode of nonaqueous Li-air batteries are known to be Li2O2 and residual Li2CO3. Recent experiments indicate that the charge transport through these materials is the main limiting factor for the battery performance. It has been also shown...... that the performance of the battery decreases drastically when the amount of Li2CO3 at the cathode increases with respect to Li2O2. In this work, we study the formation and transport of hole and electron polarons in Li2O2 and Li2CO3 using density functional theory (DFT) within the PBE+U approximation. For both...... materials, we find that the formation of polarons (both hole and electron) is stabilized with respect to the delocalized states for all physically relevant values of U. We find a much higher mobility for hole polarons than for the electron polarons, and we show that the poor charge transport in Li2CO3...

Mass transfer performance comparison of two commonly used liquid desiccants: LiBr and LiCl aqueous solutions

International Nuclear Information System (INIS)

Liu, X.H.; Yi, X.Q.; Jiang, Y.

2011-01-01

Mass transfer performance of two commonly used liquid desiccants, LiBr aqueous solution and LiCl aqueous solution, is compared in this paper on the basis of the same solution temperature and surface vapor pressure. According to the analysis of the analytical solutions of heat and mass transfer processes, the key performance influencing factors are heat capacity ratio of air to desiccant m * and mass transfer unit NTU m . The heat capacities of the two liquid desiccants are about the same at same volumetric flow rate, and LiBr solution has higher density and smaller specific heat capacity. The variance of mass transfer unit with different operating conditions and liquid desiccants are derived based on the experimental results. In the condition of the same desiccant mass flow rate, the dehumidification performance of LiCl solution is better, and the regeneration performance of LiBr solution is a little better or almost the same as that of LiCl solution. In the condition of the same desiccant volumetric flow rate, the dehumidification performance of LiCl solution is a little better or about the same compared with LiBr solution, and the regeneration performance of LiBr solution is better. The COPs of the liquid desiccant systems using these two desiccants are similar; while LiCl solution costs 18% lower than LiBr solution at current Chinese price.

[100]-Oriented LiFePO4 Nanoflakes toward High Rate Li-Ion Battery Cathode.

Science.gov (United States)

Li, Zhaojin; Peng, Zhenzhen; Zhang, Hui; Hu, Tao; Hu, Minmin; Zhu, Kongjun; Wang, Xiaohui

2016-01-13

[100] is believed to be a tough diffusion direction for Li(+) in LiFePO4, leading to the belief that the rate performance of [100]-oriented LiFePO4 is poor. Here we report the fabrication of 12 nm-thick [100]-oriented LiFePO4 nanoflakes by a simple one-pot solvothermal method. The nanoflakes exhibit unexpectedly excellent electrochemical performance, in stark contrast to what was previously believed. Such an exceptional result is attributed to a decreased thermodynamic transformation barrier height (Δμb) associated with increased active population.

CuLi2Sn and Cu2LiSn: Characterization by single crystal XRD and structural discussion towards new anode materials for Li-ion batteries.

Science.gov (United States)

Fürtauer, Siegfried; Effenberger, Herta S; Flandorfer, Hans

2014-12-01

The stannides CuLi 2 Sn (CSD-427095) and Cu 2 LiSn (CSD-427096) were synthesized by induction melting of the pure elements and annealing at 400 °C. The phases were reinvestigated by X-ray powder and single-crystal X-ray diffractometry. Within both crystal structures the ordered CuSn and Cu 2 Sn lattices form channels which host Cu and Li atoms at partly mixed occupied positions exhibiting extensive vacancies. For CuLi 2 Sn, the space group F-43m. was verified (structure type CuHg 2 Ti; a =6.295(2) Å; wR 2 ( F ²)=0.0355 for 78 unique reflections). The 4( c ) and 4( d ) positions are occupied by Cu atoms and Cu+Li atoms, respectively. For Cu 2 LiSn, the space group P 6 3 / mmc was confirmed (structure type InPt 2 Gd; a =4.3022(15) Å, c =7.618(3) Å; wR 2 ( F ²)=0.060 for 199 unique reflections). The Cu and Li atoms exhibit extensive disorder; they are distributed over the partly occupied positions 2( a ), 2( b ) and 4( e ). Both phases seem to be interesting in terms of application of Cu-Sn alloys as anode materials for Li-ion batteries.

High performance passive matrix electrochromic display

International Nuclear Information System (INIS)

Aliev, A.E.

2003-01-01

A matrix addressable electrochromic display (ECD) based on solid polymer electrolyte screen-printed on the surface of nano structured WO 3 +0.1TiO 2 electrodes, in which all pixels were insulted by negative photoresist material has been developed. Five types of nano structured films produced by a sol-gel method were investigated to enhance the electrochemical, optical, and mechanical properties of electrochromic tungsten oxide films. The film based on WO 3-x +0.1TiO 2-y sol-gel solution mixed with 32 mol.% oxalic acid was found to be stable and has excellent characteristics in coloring/bleaching kinetics. The ECD used nano structured electrochromic tungsten trioxide layer protected by SiO 2 -CeO 2 -Li 2 O thin film solid electrolyte, screen-printed solid polymer electrolyte mixed with white TiO 2 pigment (P25), and metallic counter electrode covered with carbon layer, has exhibited fast switching, excellent memory effect and substantially free from image diffusion and cross talk effects. (author)

Direct Rehydrogenation of LiBH4 from H-Deficient Li2B12H12−x

Directory of Open Access Journals (Sweden)

Yigang Yan

2018-03-01

Full Text Available Li2B12H12 is commonly considered as a boron sink hindering the reversible hydrogen sorption of LiBH4. Recently, in the dehydrogenation process of LiBH4 an amorphous H-deficient Li2B12H12−x phase was observed. In the present study, we investigate the rehydrogenation properties of Li2B12H12−x to form LiBH4. With addition of nanostructured cobalt boride in a 1:1 mass ratio, the rehydrogenation properties of Li2B12H12−x are improved, where LiBH4 forms under milder conditions (e.g., 400 °C, 100 bar H2 with a yield of 68%. The active catalytic species in the reversible sorption reaction is suggested to be nonmetallic CoxB (x = 1 based on 11B MAS NMR experiments and its role has been discussed.

Modulation of solid electrolyte interphase of lithium-ion batteries by LiDFOB and LiBOB electrolyte additives

Science.gov (United States)

Huang, Shiqiang; Wang, Shuwei; Hu, Guohong; Cheong, Ling-Zhi; Shen, Cai

2018-05-01

Solid-electrolyte interphase (SEI) layer is an organic-inorganic composite layer that allows Li+ transport across but blocks electron flow across and prevents solvent diffusing to electrode surface. Morphology, thickness, mechanical and chemical properties of SEI are important for safety and cycling performance of lithium-ion batteries. Herein, we employ a combination of in-situ AFM and XPS to investigate the effects of two electrolyte additives namely lithium difluoro(oxalate)borate (LiDFOB) and lithium bis(oxalato)borate (LiBOB) on SEI layer. LiDFOB is found to result in a thin but hard SEI layer containing more inorganic species (LiF and LiCO3); meanwhile LiBOB promotes formation of a thick but soft SEI layer containing more organic species such as ROCO2Li. Findings from present study will help development of electrolyte additives that promote formation of good SEI layer.

Cost-based optimizations of power density and target-blanket modularity for 232Th/233U-based ADEP

International Nuclear Information System (INIS)

Krakowski, R.A.

1995-01-01

A cost-based parametric systems model is developed for an Accelerator-Driven Energy Production (ADEP) system based on a 232 Th/ 233 U fuel cycle and a molten-salt (LiF/BeF 2 /ThF 3 ) fluid-fuel primary system. Simplified neutron-balance, accelerator, reactor-core, chemical-processing, and balance-of-plant models are combined parametrically with a simplified costing model. The main focus of this model is to examine trade offs related to fission power density, reactor-core modularity, 233 U breeding rate, and fission product transmutation capacity

Synthesis, Structure, and Li-Ion Conductivity of LiLa(BH4)3X, X = Cl, Br, I

DEFF Research Database (Denmark)

GharibDoust, Seyed Hosein Payandeh; Brighi, Matteo; Sadikin, Yolanda

2017-01-01

In this work, a new type of addition reaction between La(BH4)3 and LiX, X = Cl, Br, I, is used to synthesize LiLa(BH4)3Cl and two new compounds LiLa(BH4)3X, X = Br, I. This method increases the amounts of LiLa(BH4)3X and the sample purity. The highest Li-ion conductivity is observed for LiLa(BH4...... with increasing lattice parameter, that is, increasing size of the halide ion in the structure. Thus, we conclude that the sizes of both windows are important for the lithium ion conduction in LiLa(BH4)3X compounds. The lithium ion conductivity is measured over one to three heating cycles and with different...

Formation and reduction behaviors of zirconium oxide compounds in LiCl–Li{sub 2}O melt at 923 K

Energy Technology Data Exchange (ETDEWEB)

Sakamura, Yoshiharu, E-mail: sakamura@criepi.denken.or.jp [Central Research Institute of Electric Power Industry (CRIEPI), 2-11-1 Iwadokita, Komae-shi, Tokyo 201-8511 (Japan); Iizuka, Masatoshi [Central Research Institute of Electric Power Industry (CRIEPI), 2-11-1 Iwadokita, Komae-shi, Tokyo 201-8511 (Japan); Kitawaki, Shinichi; Nakayoshi, Akira; Kofuji, Hirohide [International Research Institute for Nuclear Decommissioning (IRID), 2-23-1 Nishi-shimbashi, Minato-ku, Tokyo 105-0003 (Japan); Japan Atomic Energy Agency (JAEA), 4-33 Muramatsu, Tokai-mura, Naka-gun, Ibaraki 319-1194 (Japan)

2015-11-15

The reduction behaviors of ZrO{sub 2}, Li{sub 2}ZrO{sub 3} and (U,Pu,Zr)O{sub 2} in a LiCl–Li{sub 2}O salt bath at 923 K were investigated. This study was conducted as part of a feasibility study on the pyrochemical treatment of damaged fuel debris generated by severe accidents at light water reactors. It was demonstrated in electrolytic reduction tests that the uranium in synthetic corium specimens of (U,Pu,Zr)O{sub 2} with various ZrO{sub 2} contents could be reduced to the metallic form and that part of the zirconium was converted to Li{sub 2}ZrO{sub 3}. Zirconium metal and Li{sub 2}ZrO{sub 3} were obtained by the reduction of ZrO{sub 2}. The reduction of Li{sub 2}ZrO{sub 3} did not proceed even in LiCl containing no Li{sub 2}O. Moreover, the stable chemical forms of the ZrO{sub 2}–Li{sub 2}O complex oxide were investigated as a function of the Li{sub 2}O concentration in LiCl. ZrO{sub 2} was converted to Li{sub 2}ZrO{sub 3} at a Li{sub 2}O concentration of 0.018 wt%. As the Li{sub 2}O concentration was increased, Li{sub 2}ZrO{sub 3} was converted to Li{sub 6}Zr{sub 2}O{sub 7} and then to Li{sub 8}ZrO{sub 6}. It is suggested that the removal of Li{sub 2}ZrO{sub 3} from the reduction product is a key point in the pyrochemical treatment of corium. - Highlights: • The uranium in (U,Pu,Zr)O{sub 2} could be reduced to the metallic form in LiCl–Li{sub 2}O. • Part of the zirconium was converted to Li{sub 2}ZrO{sub 3} during electrolytic reduction. • Li{sub 6}Zr{sub 2}O{sub 7} and Li{sub 8}ZrO{sub 6} formed at high Li{sub 2}O concentrations in LiCl.

Experimental study on infrared radiation temperature field of concrete under uniaxial compression

Science.gov (United States)

Lou, Quan; He, Xueqiu

2018-05-01

Infrared thermography, as a nondestructive, non-contact and real-time monitoring method, has great significance in assessing the stability of concrete structure and monitoring its failure. It is necessary to conduct in depth study on the mechanism and application of infrared radiation (IR) of concrete failure under loading. In this paper, the concrete specimens with size of 100 × 100 × 100 mm were adopted to carry out the uniaxial compressions for the IR tests. The distribution of IR temperatures (IRTs), surface topography of IRT field and the reconstructed IR images were studied. The results show that the IRT distribution follows the Gaussian distribution, and the R2 of Gaussian fitting changes along with the loading time. The abnormities of R2 and AE counts display the opposite variation trends. The surface topography of IRT field is similar to the hyperbolic paraboloid, which is related to the stress distribution in the sample. The R2 of hyperbolic paraboloid fitting presents an upward trend prior to the fracture which enables to change the IRT field significantly. This R2 has a sharp drop in response to this large destruction. The normalization images of IRT field, including the row and column normalization images, were proposed as auxiliary means to analyze the IRT field. The row and column normalization images respectively show the transverse and longitudinal distribution of the IRT field, and they have clear responses to the destruction occurring on the sample surface. In this paper, the new methods and quantitative index were proposed for the analysis of IRT field, which have some theoretical and instructive significance for the analysis of the characteristics of IRT field, as well as the monitoring of instability and failure for concrete structure.

Organophosphonic acid as precursor to prepare LiFePO4/carbon nanocomposites for high-power lithium ion batteries

International Nuclear Information System (INIS)

Chen, Ming; Shao, Leng-Leng; Yang, Hua-Bin; Zhao, Qian-Yong; Yuan, Zhong-Yong

2015-01-01

Graphical abstract: LiFePO4/C nanocomposites were prepared by a quasi-sol–gel method with the use of organophosphonic acid, exhibiting improved electrochemical performance with excellent cycle stability. Display Omitted -- Highlights: •Amino tris(methylene phosphonic acid) is served as a novel precursor for LiFePO 4 /C. •Nano-sized and high-purity LiFePO 4 /C composites are obtained by a quasi-sol–gel route. •Core-shell structured LiFePO 4 /C nanocomposites are fabricated by further introducing sucrose. •Superior electrochemical performance is observed in the organophosphorus-synthesized LiFePO 4 /C. -- Abstract: Amino tris(methylene phosphonic acid) (ATMP) is selected as phosphorus and carbon co-source for the synthesis of uniformly nano-sized LiFePO 4 /C by a quasi-sol–gel method. This strategy using ATMP instead of conventional NH 4 H 2 PO 4 supplies two advantages: firstly, ATMP in situ chelates Li + onto its framework and subsequently binds with FeC 2 O 4 in aqueous solution, forming a molecule-scale homogeneous precursor which can obviously improve the purity of LiFePO 4 . Secondly, the organic carbon contained in ATMP can form uniformly distributed conductive carbon networks among LiFePO 4 particles after calcination, which improves the electrical conductivity. The resultant LiFePO 4 /C with 1.1 wt.% carbon achieves a higher discharge capacity than those of LiFePO 4 and LiFePO 4 /C prepared with inorganic NH 4 H 2 PO 4 . Moreover, core-shell structured LiFePO 4 /C nanocomposites are also fabricated by further introducing sucrose into the synthesis system. The high-quality carbon shell effectively hinders the LiFePO 4 particle growth and aggregation under high-temperature treatment, which further enhances the electrical conductivity and lithium-ion diffusion, resulting in the improved electrochemical performance with excellent cycle stability (the optimum discharge capacity of 158.6 mAh g −1 at 0.1 C and 138.4 mAh g −1 at 2 C). The high

Measurements of the fundamental thermodynamic parameters of Li/BCX and Li/SOCl2 cells

Science.gov (United States)

Kalu, E. E.; White, R. E.; Darcy, E. C.

1992-01-01

Two experimental techniques - equilibrium or reversible cell discharge and measurement of open circuit potential as a function of temperature - are used to determine the thermodynamic data needed to estimate the heat generation characteristics of Li/BCX and Li/SOCl2 cells. The results obtained showed that the reversible cell potential, the temperature dependence of the reversible cell potential, and the thermoneutral potential of the BCX cell were 3.74 V, -0.857 +/- 0.198 mV/K, and 3.994 +/- 0.0603 V, respectively. The respective values obtained for the Li/SOCl2 cell were 3.67 V, -0.776 +/- 0.255 mV/K, and 3.893 +/- 0.0776 V. The difference between the thermoneutral potential of Li/BCX and Li/SCl2 cells is attributable to the difference in their electroactive components.

Reoxidation of uranium metal immersed in a Li2O-LiCl molten salt after electrolytic reduction of uranium oxide

Science.gov (United States)

Choi, Eun-Young; Jeon, Min Ku; Lee, Jeong; Kim, Sung-Wook; Lee, Sang Kwon; Lee, Sung-Jai; Heo, Dong Hyun; Kang, Hyun Woo; Jeon, Sang-Chae; Hur, Jin-Mok

2017-03-01

We present our findings that uranium (U) metal prepared by using the electrolytic reduction process for U oxide (UO2) in a Li2O-LiCl salt can be reoxidized into UO2 through the reaction between the U metal and Li2O in LiCl. Two salt types were used for immersion of the U metal: one was the salt used for electrolytic reduction, and the other was applied to the unused LiCl salts with various concentrations of Li2O and Li metal. Our results revealed that the degree of reoxidation increases with the increasing Li2O concentration in LiCl and that the presence of the Li metal in LiCl suppresses the reoxidation of the U metal.

7Li(d,p)8Li transfer reaction in the NCSM/RGM approach

Science.gov (United States)

Raimondi, F.; Hupin, G.; Navrátil, P.; Quaglioni, S.

2018-03-01

Recently, we applied an ab initio method, the no-core shell model combined with the resonating group method, to the transfer reactions with light p-shell nuclei as targets and deuteron as the projectile. In particular, we studied the elastic scattering of deuterium on 7Li and the 7Li(d,p)8Li transfer reaction starting from a realistic two-nucleon interaction. In this contribution, we review of our main results on the 7Li(d,p)8Li transfer reaction, and we extend the study of the relevant reaction channels, by showing the dominant resonant phase shifts of the scattering matrix. We assess also the impact of the polarization effects of the deuteron below the breakup on the positive-parity resonant states in the reaction. For this purpose, we perform an analysis of the convergence trend of the phase and eigenphase shifts, with respect to the number of deuteron pseudostates included in the model space.

Electrochemical performance of LiFePO4 modified by pressure-pulsed chemical vapor infiltration in lithium-ion batteries

International Nuclear Information System (INIS)

Li Jianling; Suzuki, Tomohiro; Naga, Kazuhisa; Ohzawa, Yoshimi; Nakajima, Tsuyoshi

2007-01-01

Using the pressure-pulsed chemical vapor infiltration (PCVI) technique, pyrolytic carbon (pyrocarbon) films were deposited on the surface of LiFePO 4 particles for cathode material of lithium-ion batteries. The electrochemical performance of the original LiFePO 4 and PCVIed LiFePO 4 materials was evaluated using a three electrodes cell by galvanostatic charging/discharging at 25, 40 and 55 deg. C, respectively. Morphology and structure of LiFePO 4 were analyzed by SEM, XRD and Raman. The resulting carbon contents at 500, 1000, 2000, 3000 and 5000 pulses were 2.7, 4.7, 9.5, 15.1 and 19.4%, respectively and these samples were abbreviated as 500P, 1000P, 2000P, 3000P and 5000P, respectively. All the PCVIed samples exhibited excellent rate performance. The tendency was more and more obvious with the increase of the current densities. The specific capacities of 500P, 1000P and 2000P were maintained at 117, 124 and 132 mAh g -1 , respectively, which were 120.8, 264.7 and 29.47% larger than those of corresponding original LiFePO 4 , respectively, at a 5C rate at 55 deg. C. The EIS measurement showed that electrochemical reaction resistance (R ct ) of PCVIed LiFePO 4 were obviously decreased, indicating a fast kinetics compared to the original LiFePO 4 . The cycle ability of the 2000P sample was tested at 25 deg. C and C/2 rate. The cell was cycled for 150 cycles and no obviously capacity fade was observed. Its specific capacity of 115 mAh g -1 at 150th cycle is 1.7 times higher than that of original LiFePO 4

Single-crystalline LiFePO4 nanosheets for high-rate Li-ion batteries.

Science.gov (United States)

Zhao, Yu; Peng, Lele; Liu, Borui; Yu, Guihua

2014-05-14

The lithiation/delithiation in LiFePO4 is highly anisotropic with lithium-ion diffusion being mainly confined to channels along the b-axis. Controlling the orientation of LiFePO4 crystals therefore plays an important role for efficient mass transport within this material. We report here the preparation of single crystalline LiFePO4 nanosheets with a large percentage of highly oriented {010} facets, which provide the highest pore density for lithium-ion insertion/extraction. The LiFePO4 nanosheets show a high specific capacity at low charge/discharge rates and retain significant capacities at high C-rates, which may benefit the development of lithium batteries with both favorable energy and power density.

Li-atoms-induced structure changes of Guinier–Preston–Bagaryatsky zones in AlCuLiMg alloys

Energy Technology Data Exchange (ETDEWEB)

Duan, S.Y.; Le, Z.; Chen, Z.K.; Gao, Z. [Center for High-Resolution Electron Microscopy, College of Materials Science and Engineering, Hunan University, Changsha, Hunan 410082 (China); Chen, J.H., E-mail: jhchen123@hnu.edu.cn [Center for High-Resolution Electron Microscopy, College of Materials Science and Engineering, Hunan University, Changsha, Hunan 410082 (China); Advanced Research Center, Central South University, Changsha 410083 (China); Ming, W.Q.; Li, S.Y.; Wu, C.L. [Center for High-Resolution Electron Microscopy, College of Materials Science and Engineering, Hunan University, Changsha, Hunan 410082 (China); Yan, N. [Advanced Research Center, Central South University, Changsha 410083 (China)

2016-11-15

Guinier–Preston–Bagaryatsky (GPB) zones are the well-known strengthening precipitates of AlCuMg alloys formed upon thermal ageing. Here we report that when formed in AlCuLiMg alloys the GPB zones can change significantly in morphology and structure. It is shown that though they do still consist of Al, Cu and Mg elements fundamentally, the GPB zones in AlCuLiMg alloys have a rather different structure due to a featured Li-segregation at their interfaces with the matrix and possible Li-replacement of partial Mg atoms in the structure. As such the Li-containing GPB zones often develop from one-dimensional to quasi-two-dimensional precipitates. - Highlights: • We observe Guinier–Preston–Bagaryatsky zone variants in AlCuLiMg alloys. • We obtain atomic-resolution images of the precipitates and model their structures. • Li-atoms play a key role in modifying the structure of these precipitate variants.

Reoxidation of uranium metal immersed in a Li{sub 2}O-LiCl molten salt after electrolytic reduction of uranium oxide

Energy Technology Data Exchange (ETDEWEB)

Choi, Eun-Young, E-mail: eychoi@kaeri.re.kr [Korea Atomic Energy Research Institute, Daedoek-daero 989-111, Yuseong-gu, Daejeon 34057 (Korea, Republic of); Jeon, Min Ku [Korea Atomic Energy Research Institute, Daedoek-daero 989-111, Yuseong-gu, Daejeon 34057 (Korea, Republic of); Department of Quantum Energy Chemical Engineering, University of Science and Technology, Gajeong-ro 217, Yuseong-gu, Daejeon 34113 (Korea, Republic of); Lee, Jeong [Korea Atomic Energy Research Institute, Daedoek-daero 989-111, Yuseong-gu, Daejeon 34057 (Korea, Republic of); Kim, Sung-Wook [Korea Atomic Energy Research Institute, Daedoek-daero 989-111, Yuseong-gu, Daejeon 34057 (Korea, Republic of); Department of Quantum Energy Chemical Engineering, University of Science and Technology, Gajeong-ro 217, Yuseong-gu, Daejeon 34113 (Korea, Republic of); Lee, Sang Kwon [Korea Atomic Energy Research Institute, Daedoek-daero 989-111, Yuseong-gu, Daejeon 34057 (Korea, Republic of); Lee, Sung-Jai [Korea Atomic Energy Research Institute, Daedoek-daero 989-111, Yuseong-gu, Daejeon 34057 (Korea, Republic of); Department of Quantum Energy Chemical Engineering, University of Science and Technology, Gajeong-ro 217, Yuseong-gu, Daejeon 34113 (Korea, Republic of); Heo, Dong Hyun; Kang, Hyun Woo; Jeon, Sang-Chae; Hur, Jin-Mok [Korea Atomic Energy Research Institute, Daedoek-daero 989-111, Yuseong-gu, Daejeon 34057 (Korea, Republic of)

2017-03-15

We present our findings that uranium (U) metal prepared by using the electrolytic reduction process for U oxide (UO{sub 2}) in a Li{sub 2}O–LiCl salt can be reoxidized into UO{sub 2} through the reaction between the U metal and Li{sub 2}O in LiCl. Two salt types were used for immersion of the U metal: one was the salt used for electrolytic reduction, and the other was applied to the unused LiCl salts with various concentrations of Li{sub 2}O and Li metal. Our results revealed that the degree of reoxidation increases with the increasing Li{sub 2}O concentration in LiCl and that the presence of the Li metal in LiCl suppresses the reoxidation of the U metal. - Highlights: • Uranium (U) metal can be reoxidized into UO{sub 2} through the reaction between the U metal and Li{sub 2}O in LiCl. • The degree of reoxidation increases with the Li{sub 2}O concentration in LiCl. • The presence of the Li metal in LiCl suppresses the reoxidation of the U metal.

2013 Puget Sound LiDAR Consortium (PSLC) Topographic LiDAR: Tulalip Partnership

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — In October 2012, WSI (Watershed Sciences, Inc.) was contracted by the Puget Sound LiDAR Consortium (PSLC)to collect Light Detection and Ranging (LiDAR) data on a...

2013 Puget Sound LiDAR Consortium (PSLC) Topographic LiDAR: Saddle Mountain

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — In October 2013, WSI, a Quantum Spatial Company (QSI), was contracted by the Puget Sound LiDAR Consortium (PSLC) to collect Light Detection and Ranging (LiDAR) data...

Estimating Stand Volume and Above-Ground Biomass of Urban Forests Using LiDAR

Directory of Open Access Journals (Sweden)

Vincenzo Giannico

2016-04-01

Full Text Available Assessing forest stand conditions in urban and peri-urban areas is essential to support ecosystem service planning and management, as most of the ecosystem services provided are a consequence of forest stand characteristics. However, collecting data for assessing forest stand conditions is time consuming and labor intensive. A plausible approach for addressing this issue is to establish a relationship between in situ measurements of stand characteristics and data from airborne laser scanning (LiDAR. In this study we assessed forest stand volume and above-ground biomass (AGB in a broadleaved urban forest, using a combination of LiDAR-derived metrics, which takes the form of a forest allometric model. We tested various methods for extracting proxies of basal area (BA and mean stand height (H from the LiDAR point-cloud distribution and evaluated the performance of different models in estimating forest stand volume and AGB. The best predictors for both models were the scale parameters of the Weibull distribution of all returns (except the first (proxy of BA and the 95th percentile of the distribution of all first returns (proxy of H. The R2 were 0.81 (p < 0.01 for the stand volume model and 0.77 (p < 0.01 for the AGB model with a RMSE of 23.66 m3·ha−1 (23.3% and 19.59 Mg·ha−1 (23.9%, respectively. We found that a combination of two LiDAR-derived variables (i.e., proxy of BA and proxy of H, which take the form of a forest allometric model, can be used to estimate stand volume and above-ground biomass in broadleaved urban forest areas. Our results can be compared to other studies conducted using LiDAR in broadleaved forests with similar methods.

"Radostně přijímám, co se koná pro mou záchranu" - křesťanství a existencialismus v díle Eugena Lišky

OpenAIRE

Liška, Eugen

2007-01-01

This text concerns on virtually uknown literary work of Eugen Liška - the Czech catholic writer of second half of the 20th century. First chapter introduces unpublished text of Liška's debut, short stories book with the title "Čas bez lásky" ("Time Without Love"), which was not published because of the beginning of communist dictatorship in 1948. We seek and find connections of Liška's short stories to European existencialism and present term "Christian existencialism" with help of the philos...

Li/Li2 supersonic nozzle beam

International Nuclear Information System (INIS)

Wu, C.Y.R.; Crooks, J.B.; Yang, S.C.; Way, K.R.; Stwalley, W.C.

1977-01-01

The characterization of a lithium supersonic nozzle beam was made using spectroscopic techniques. It is found that at a stagnation pressure of 5.3 kPa (40 torr) and a nozzle throat diameter of 0.4 mm the ground state vibrational population of Li 2 can be described by a Boltzmann distribution with T/sub v/ = 195 +- 30 0 K. The rotational temperature is found to be T/sub r/ = 70 +- 20 0 K by band shape analysis. Measurements by quadrupole mass spectrometer indicates that approximately 10 mole per cent Li 2 dimers are formed at an oven body temperature of 1370 0 K n the supersonic nozzle expansion. This measured mole fraction is in good agreement with the existing dimerization theory

What are the appropriate methods for analyzing patient-reported outcomes in randomized trials when data are missing?

Science.gov (United States)

Hamel, J F; Sebille, V; Le Neel, T; Kubis, G; Boyer, F C; Hardouin, J B

2017-12-01

Subjective health measurements using Patient Reported Outcomes (PRO) are increasingly used in randomized trials, particularly for patient groups comparisons. Two main types of analytical strategies can be used for such data: Classical Test Theory (CTT) and Item Response Theory models (IRT). These two strategies display very similar characteristics when data are complete, but in the common case when data are missing, whether IRT or CTT would be the most appropriate remains unknown and was investigated using simulations. We simulated PRO data such as quality of life data. Missing responses to items were simulated as being completely random, depending on an observable covariate or on an unobserved latent trait. The considered CTT-based methods allowed comparing scores using complete-case analysis, personal mean imputations or multiple-imputations based on a two-way procedure. The IRT-based method was the Wald test on a Rasch model including a group covariate. The IRT-based method and the multiple-imputations-based method for CTT displayed the highest observed power and were the only unbiased method whatever the kind of missing data. Online software and Stata® modules compatibles with the innate mi impute suite are provided for performing such analyses. Traditional procedures (listwise deletion and personal mean imputations) should be avoided, due to inevitable problems of biases and lack of power.

High-frequency Lamb wave device composed of MEMS structure using LiNbO3 thin film and air gap.

Science.gov (United States)

Kadota, Michio; Ogami, Takashi; Yamamoto, Kansho; Tochishita, Hikari; Negoro, Yasuhiro

2010-11-01

High-frequency devices operating at 3 GHz or higher are required, for instance, for future 4th generation mobile phone systems in Japan. Using a substrate with a high acoustic velocity is one method to realize a high-frequency acoustic or elastic device. A Lamb wave has a high velocity when the substrate thickness is thin. To realize a high-frequency device operating at 3 GHz or higher using a Lamb wave, a very thin (less than 0.5 μm thick) single-crystal plate must be used. It is difficult to fabricate such a very thin single crystal plate. The authors have attempted to use a c-axis orientated epitaxial LiNbO(3) thin film deposited by a chemical vapor deposition system (CVD) instead of using a thin LiNbO(3) single crystal plate. Lamb wave resonators composed of a interdigital transducer (IDT)/the LiNbO(3) film/air gap/base substrate structure like micro-electromechanical system (MEMS) transducers were fabricated. These resonators have shown a high frequency of 4.5 and 6.3 GHz, which correspond to very high acoustic velocities of 14,000 and 12,500 m/s, respectively, have excellent characteristics such as a ratio of resonant and antiresonant impedance of 52 and 38 dB and a wide band of 7.2% and 3.7%, respectively, and do not have spurious responses caused by the 0th modes of shear horizontal (SH(0)) and symmetric (S(0)) modes.

Effect of [Li]/[Nb] ratio on composition and defect structure of Zr:Yb:Tm:LiNbO3 crystals

Science.gov (United States)

Liu, Chunrui; Dai, Li; Wang, Luping; Shao, Yu; Yan, Zhehua; Xu, Yuheng

2018-04-01

Zr:Yb:Tm:LiNbO3 crystals with various [Li]/[Nb] ratios (0.946, 1.05, 1.20 and 1.38) were grown by the Czochralski technique. Distribution coefficients of Zr4+, Yb3+ and Tm3+ ions were analyzed by the inductively coupled plasma-atomic emission spectrometer (ICP-AES). The influence of [Li]/[Nb] ratio on the composition and defect structure of Zr:Yb:Tm:LiNbO3 crystals was investigated by X-ray diffraction and IR transmission spectrum. The results show that as the [Li]/[Nb] ratio increases in the melt, the distribution coefficients of Yb3+ and Tm3+ ions both increase while that of Zr4+ ion deceases. When the [Li]/[Nb] ratio increases to 1.20 in the melt, Zr:Yb:Tm:LiNbO3 crystal is nearly stoichiometric. In addition, when the [Li]/[Nb] ratio reaches up to 1.38, NbLi4+ are completely replaced and Li+ starts to impel the Zr4+, Yb3+ and Tm3+ into the normal Li sites.

Nuclear charge radius of 11Li

International Nuclear Information System (INIS)

Sanchez, Rodolfo; Noertershaeuser, Wilfried; Dax, Andreas; Ewald, Guido; Goette, Stefan; Kirchner, Reinhard; Kluge, H.-Juergen; Kuehl, Thomas; Wojtaszek, Agnieszka; Bushaw, Bruce A.; Drake, Gordon W. F.; Yan Zongchao; Zimmermann, Claus; Albers, Daniel; Behr, John; Bricault, Pierre; Dilling, Jens; Dombsky, Marik; Lassen, Jens; Phil Levy, C. D.

2006-01-01

We have determined the nuclear charge radius of 11 Li by high-precision laser spectroscopy. The experiment was performed at the TRIUMF-ISAC facility where the 7 Li- 11 Li isotope shift (IS) was measured in the 2s → 3s electronic transition using Doppler-free two-photon spectroscopy with a relative accuracy better than 10 -5 . The accuracy for the IS of the other lithium isotopes was also improved. IS's are mainly caused by differences in nuclear mass, but changes in proton distribution also give small contributions. Comparing experimentally measured IS with advanced atomic calculation of purely mass-based shifts, including QED and relativistic effects, allows derivation of the nuclear charge radii. The radii are found to decrease monotonically from 6 Li to 9 Li, and then increase with 11 Li about 11% larger than 9 Li. These results are a benchmark for the open question as to whether nuclear core excitation by halo neutrons is necessary to explain the large nuclear matter radius of 11 Li; thus, the results are compared with a number of nuclear structure models.

Fabrication and tritium release property of Li2TiO3-Li4SiO4 biphasic ceramics

Science.gov (United States)

Yang, Mao; Ran, Guangming; Wang, Hailiang; Dang, Chen; Huang, Zhangyi; Chen, Xiaojun; Lu, Tiecheng; Xiao, Chengjian

2018-05-01

Li2TiO3-Li4SiO4 biphasic ceramic pebbles have been developed as an advanced tritium breeder due to the potential to combine the advantages of both Li2TiO3 and Li4SiO4. Wet method was developed for the pebble fabrication and Li2TiO3-Li4SiO4 biphasic ceramic pebbles were successfully prepared by wet method using the powders synthesized by hydrothermal method. The tritium release properties of the Li2TiO3-Li4SiO4 biphasic ceramic pebbles were evaluated. The biphasic pebbles exhibited good tritium release property at low temperatures and the tritium release temperature was around 470 °C. Because of the isotope exchange reaction between H2 and tritium, the addition of 0.1%H2 to purge gas He could significantly enhance the tritium gas release and the fraction of molecular form of tritium increased from 28% to 55%. The results indicate that the Li2TiO3-Li4SiO4 biphasic ceramic pebbles fabricated by wet method exhibit good tritium release property and hold promising potential as advanced breeder pebbles.

Simplified PCR protocols for INNO-LiPA HBV Genotyping and INNO-LiPA HBV PreCore assays

NARCIS (Netherlands)

Qutub, Mohammed O.; Germer, Jeffrey J.; Rebers, Sjoerd P. H.; Mandrekar, Jayawant N.; Beld, Marcel G. H. M.; Yao, Joseph D. C.

2006-01-01

INNO-LiPA HBV Genotyping (LiPA HBV GT) and INNO-LiPA HBV PreCore (LiPA HBV PC) are commercially available assays for hepatitis B virus (HBV) characterization. These assays are labor-intensive and may be prone to exogenous DNA contamination due to their use of nested PCR amplification procedures and

Properties of the LiCl-KCl-Li2O system as operating medium for pyro-chemical reprocessing of spent nuclear fuel

Science.gov (United States)

Mullabaev, Albert; Tkacheva, Olga; Shishkin, Vladimir; Kovrov, Vadim; Zaikov, Yuriy; Sukhanov, Leonid; Mochalov, Yuriy

2018-03-01

Crystallization temperatures (liquidus and solidus) in the LiCl-Li2O and (LiCl-KCl)-Li2O systems with the KCl content of 10 and 20 mol.% were obtained with independent methods of thermal analysis using cooling curves, isothermal saturation, and differential scanning calorimetry. The linear sweep voltammetry was applied to control the time of the equilibrium establishment in the molten system after the Li2O addition, which depended on the composition of the base melt and the concentration of Li2O. The fragments of the binary LiCl-Li2O and quazi-binary [LiCl-KCl(10 mol.%)]-Li2O and [LiCl-KCl(20 mol.%)]-Li2O phase diagrams in the Li2O concentration range from 0 to 12 mol.% were obtained. The KCl presence in the LiCl-KCl-Li2O molten mixture in the amount of 10 and 20 mol.% reduces the liquidus temperature by 30 and 80°, respectively, but the region of the homogeneous molten state of the system is considerably narrowed, which complicates its practical application. The Li2O solubility in the molten LiCl, LiCl-KCl(10 mol.%) and LiCl-KCl(20 mol.%) decreases with increasing the KCl content and is equal to 11.5, 7.7 and 3.9 mol.% at 650°С, respectively. The LiCl-KCl melt with 10 mol.% KCl can be recommended for practical use as a medium for the SNF pyro-chemical reprocessing at temperature below 700 °C.

TID Test Results for 4th Generation iPad(TradeMark)

Science.gov (United States)

Guertin, S. M.; Allen, G. R.; McClure, S. S.; LaBel, K. A.

2013-01-01

TID testing of 4th generation iPads is reported. Of iPad subsystems, results indicate that the charging circuitry and display drivers fail at lowest TID levels. Details of construction are investigated for additional testing of components.

Combustion synthesized nanocrystalline Li3V2(PO4)3/C cathode for lithium-ion batteries

International Nuclear Information System (INIS)

Nathiya, K.; Bhuvaneswari, D.; Gangulibabu; Kalaiselvi, N.

2012-01-01

Graphical abstract: Nanocrystalline Li 3 V 2 (PO 4 ) 3 /C compound has been synthesized using a novel corn assisted combustion (CAC) method, wherein the composite prepared at 850 °C is found to exhibit superior physical and electrochemical properties than the one synthesized at 800 °C (Fig. 1). Despite the charge disproportionation of V 4+ and a possible solid solution behavior of Li 3 V 2 (PO 4 ) 3 cathode upon insertion and de-insertion of Li + ions, the structural stability of the same is appreciable, even with the extraction of third lithium at 4.6 V (Fig. 2). An appreciable specific capacity of 174 mAh g −1 with an excellent columbic efficiency (99%) and better capacity retention upon high rate applications have been exhibited by Li 3 V 2 (PO 4 ) 3 /C cathode, thus demonstrating the feasibility of CAC method in preparing the title compound to best suit with the needs of lithium battery applications. Display Omitted Highlights: ► Novel corn assisted combustion method has been used to synthesize Li 3 V 2 (PO 4 ) 3 /C. ► Corn is a cheap and eco benign combustible fuel to facilitate CAC synthesis. ► Li 3 V 2 (PO 4 ) 3 /C exhibits an appreciable specific capacity of 174 mAh g −1 (C/10 rate). ► Currently observed columbic efficiency of 99% is better than the reported behavior. ► Suitability of Li 3 V 2 (PO 4 ) 3 /C cathode up to 10C rate is demonstrated. -- Abstract: Nanocrystalline Li 3 V 2 (PO 4 ) 3 /C composite synthesized using a novel corn assisted combustion method at 850 °C exhibits superior physical and electrochemical properties than the one synthesized at 800 °C. Despite the charge disproportionation of V 4+ and a possible solid solution behavior of Li 3 V 2 (PO 4 ) 3 cathode upon insertion and extraction of Li + ions, the structural stability of the same is appreciable, even with the extraction of third lithium at 4.6 V. An appreciable specific capacity of 174 mAh g −1 and better capacity retention upon high rate applications have been

The tin-rich copper lithium stannides: Li3Cu6Sn4 and Li2CuSn2

International Nuclear Information System (INIS)

Fuertauer, Siegfried; Flandorfer, Hans; Effenberger, Herta S.

2015-01-01

The Sn rich ternary intermetallic compounds Li 3 Cu 6 Sn 4 (CSD-427097) and Li 2 CuSn 2 (CSD-427098) were synthesized from the pure elements by induction melting and annealing at 400 C. Structural investigations were performed by powder- and single-crystal XRD. Li 3 Cu 6 Sn 4 crystallizes in space group P6/mmm; it is structurally related to but not isotypic with MgFe 6 Ge 6 (a = 5.095(2) Aa, c = 9.524(3) Aa; wR 2 = 0.059; 239 unique F 2 -values, 17 free variables). Li 3 Cu 6 Sn 4 is characterized by two sites with a mixed Cu:Sn occupation. In contrast to all other Cu-Li-Sn compounds known so far, any mixed occupation was found for Cu-Li pairs only. In addition, one Li site is only half occupied. The second Sn rich phase is Li 2 CuSn 2 (space group I4 1 /amd, a = 4.4281(15) Aa, c = 19.416(4) Aa; wR 2 = 0.033; 213 unique F 2 -values, 12 atom free variables); it is the only phase in the Cu-Li-Sn system which is noted for full ordering. Both crystal structures exhibit 3D-networks which host Li atoms in channels. They are important for understanding the lithiation mechanism in Cu-Sn electrodes for Li-ion batteries.

Experiments on iron shield transmission of quasi-monoenergetic neutrons generated by 43- and 68-MeV protons via the {sup 7}Li(p,n) reaction

Energy Technology Data Exchange (ETDEWEB)

Nakashima, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Tanaka, Shun-ichi; Nakao, Noriaki [and others

1996-03-01

In order to provide benchmark data of neutrons transmitted through iron shields in the intermediate-energy region, spatial distributions of neutron energy spectra and reaction rates behind and inside the iron shields of thickness up to 130 cm were measured for 43- and 68-MeVp-{sup 7}Li neutrons using a quasi-monoenergetic neutron beam source at the 90-MV AVF cyclotron facility of the TLARA facility in JAERI. The measured data by five kinds of detectors: the BC501A detector, the Bonner ball counter, {sup 238}U and {sup 232}Th fission counters, {sup 7}LiF and {sup nat}LiF TLDs and solid state nuclear track detector, are numerically provided in this report in the energy region between 10{sup -4} eV and the energy of peak neutrons generated by the {sup 7}Li(p,n) reaction. (author).

Monitoring readiness of safety relevant devices in nuclear power plants by means of CRT-colour displays

International Nuclear Information System (INIS)

Haubert, R.; Stokke, R.

1980-01-01

The development of an information system for monitoring readiness of safety relevant devices is encouraged by the requirements of KTA-rule 3501 (DIN 25434), which states in section 4.9.1.1. 'A display shall be provided for giving a survey of the condition of the components of the reactor protection system and the active engineered safeguards including their energy and auxiliary media supplies'. In the first stage of the development which was reported at the Enlarged Halden Programme Group Meeting in Loen, Norway, 5th-9th June, 1978, only the components of parts of a BWR-protection system were considered and no display was provided. This paper outlines the next step in the development which comprises implementation of the active engineered safeguards into the system and development of a display system based on a colour CRT-screen. A prototype of this computer-based system for monitoring of protection systems has been established, and it is planned to demonstrate this prototype system using the computer equipment at GRS, Garching (orig./HP)

Storage and Effective Migration of Li-Ion for Defected β-LiFePO4 Phase Nanocrystals.

Science.gov (United States)

Guo, Hua; Song, Xiaohe; Zhuo, Zengqing; Hu, Jiangtao; Liu, Tongchao; Duan, Yandong; Zheng, Jiaxin; Chen, Zonghai; Yang, Wanli; Amine, Khalil; Pan, Feng

2016-01-13

Lithium iron phosphate, a widely used cathode material, crystallizes typically in olivine-type phase, α-LiFePO4 (αLFP). However, the new phase β-LiFePO4 (βLFP), which can be transformed from αLFP under high temperature and pressure, is originally almost electrochemically inactive with no capacity for Li-ion battery, because the Li-ions are stored in the tetrahedral [LiO4] with very high activation barrier for migration and the one-dimensional (1D) migration channels for Li-ion diffusion in αLFP disappear, while the Fe ions in the β-phase are oriented similar to the 1D arrangement instead. In this work, using experimental studies combined with density functional theory calculations, we demonstrate that βLFP can be activated with creation of effective paths of Li-ion migration by optimized disordering. Thus, the new phase of βLFP cathode achieved a capacity of 128 mAh g(-1) at a rate of 0.1 C (1C = 170 mA g(-1)) with extraordinary cycling performance that 94.5% of the initial capacity retains after 1000 cycles at 1 C. The activation mechanism can be attributed to that the induced disorder (such as FeLiLiFe antisite defects, crystal distortion, and amorphous domains) creates new lithium migration passages, which free the captive stored lithium atoms and facilitate their intercalation/deintercalation from the cathode. Such materials activated by disorder are promising candidate cathodes for lithium batteries, and the related mechanism of storage and effective migration of Li-ions also provides new clues for future design of disordered-electrode materials with high capacity and high energy density.

Electrical characteristics of Li(Ni7/10Fe3/10)VO4 ceramics

International Nuclear Information System (INIS)

Ram, Moti

2011-01-01

Graphical abstract: Display Omitted Research highlights: → The compound [Li(Ni 7/10 Fe 3/10 )VO 4 ] was synthesized by a solution-based chemical method. → Structural, microstructural and electrical properties are studied using X-ray diffraction, field emission scanning electron microscopy and complex impedance spectroscopy techniques, respectively. → Electrical conductivity study indicates that electrical conduction in the material is a thermally activated process. - Abstract: The compound [Li(Ni 7/10 Fe 3/10 )VO 4 ] was produced by a solution-based chemical route whose electrical properties were investigated using complex impedance spectroscopy technique. X-ray diffraction study reveals an orthorhombic unit cell structure of the compound. Complex electrical impedance analysis exhibits: (i) grain interior, grain boundary and electrode-material interface contributions to electrical response and (ii) the presence of temperature dependent electrical relaxation phenomena in the material. Electrical conductivity study indicates that electrical conduction in the material is a thermally activated process.

Xiao Qing Li

Indian Academy of Sciences (India)

Home; Journals; Pramana – Journal of Physics. Xiao Qing Li. Articles written in Pramana – Journal of Physics. Volume 78 Issue 3 March 2012 pp 439-449 Research Articles. Modulation instability of an intense laser beam in an unmagnetized electron–positron–ion plasma · San Qiu Liu Wei Tang Xiao Qing Li · More Details ...

Ab initio study of isomerism of Li2AB2 molecules and Li2AB2+ ions with 16 valent electrons

International Nuclear Information System (INIS)

Charkin, O.P.; Klimenko, N.M.; MakKi, M.L.

2000-01-01

In the framework of MP2(6-31*//HF/6-31G + ZPE(HF/6-31G*) and MP4SDTQ/6-31G*//MP2/6-31G* + ZPE(MP2/6-31G*) approximations ab initio calculations of surfaces of potential energy of molecules of lithium salts of Li 2 AB 2 (Li 2 BeO 2 , L 2 MgO 2 , Li 2 BeS 2 , Li 2 MgS 2 , Li 2 CN 2 , Li 2 SiN 2 , Li 2 CP 2 ) type and ions of Li 2 AB 2 + (Li 2 BO 2 + , Li 2 AlO 2 + , Li 2 BS 2 + , Li 2 AlS 2 + , Li 2 N 3 + , Li 2 PN 2 + , Li 2 P 3 + ) type with 16 valent electrons are done. For oxide and nitride systems global minimum corresponds to symmetric linear structure D ∞h and for their sulfide and phosphorus analogues curved plane or unplane (C 2 ) structure with bond angle φ(LBA)=90-110 Deg are preferable. Equilibrium geometric parameters, relative energies and energies of isomer decomposition, frequencies and IR-intensities of normal vibrations are determined [ru

Synthesis of LiFePO4/Li2SiO3/reduced Graphene Oxide (rGO) Composite via Hydrothermal Method

Science.gov (United States)

Arifin, M.; Iskandar, F.; Aimon, A. H.; Munir, M. M.; Nuryadin, B. W.

2016-08-01

LiFePO4 is a type of cathode active material used for lithium ion batteries. It has a high electrochemical performance. However, it suffers from certain disadvantages such as a very low intrinsic electronic conductivity and low ionic diffusion. This study was conducted to increase the conductivity of LiFePO4. We have investigated the addition of Li2SiO3 and reduced graphene oxide (rGO) to LiFePO4. The objective of this research was to synthesize LiFePO4/Li2SiO3/rGO via hydrothermal method. Fourier transform infrared spectroscopy (FTIR) measurement showed that the peaks corresponded to the vibration of LiFePO4/Li2SiO3. Further, X-ray diffraction (XRD) measurement confirmed a single phase of LiFePO4. Finally, scanning electron microscopy (SEM) images showed that rGO was distributed on the LiFePO4/Li2SiO3 structure.

Synthesis of LiFePO4/Li2SiO3/reduced Graphene Oxide (rGO) Composite via Hydrothermal Method

International Nuclear Information System (INIS)

Arifin, M; Iskandar, F; Aimon, A H; Munir, M M; Nuryadin, B W

2016-01-01

LiFePO 4 is a type of cathode active material used for lithium ion batteries. It has a high electrochemical performance. However, it suffers from certain disadvantages such as a very low intrinsic electronic conductivity and low ionic diffusion. This study was conducted to increase the conductivity of LiFePO4. We have investigated the addition of Li2SiO3 and reduced graphene oxide (rGO) to LiFePO4. The objective of this research was to synthesize LiFePO 4 /Li 2 SiO 3 /rGO via hydrothermal method. Fourier transform infrared spectroscopy (FTIR) measurement showed that the peaks corresponded to the vibration of LiFePO 4 /Li 2 SiO 3 . Further, X-ray diffraction (XRD) measurement confirmed a single phase of LiFePO4. Finally, scanning electron microscopy (SEM) images showed that rGO was distributed on the LiFePO 4 /Li 2 SiO 3 structure. (paper)

Magnetic evaluation of hydrogen pressures changes on MHD fluctuations in IR-T1 tokamak plasma

Science.gov (United States)

Alipour, Ramin; Ghanbari, Mohamad R.

2018-04-01

Identification of tokamak plasma parameters and investigation on the effects of each parameter on the plasma characteristics is important for the better understanding of magnetohydrodynamic (MHD) activities in the tokamak plasma. The effect of different hydrogen pressures of 1.9, 2.5 and 2.9 Torr on MHD fluctuations of the IR-T1 tokamak plasma was investigated by using of 12 Mirnov coils, singular value decomposition and wavelet analysis. The parameters such as plasma current, loop voltage, power spectrum density, energy percent of poloidal modes, dominant spatial structures and temporal structures of poloidal modes at different plasma pressures are plotted. The results indicate that the MHD activities at the pressure of 2.5 Torr are less than them at other pressures. It also has been shown that in the stable area of plasma and at the pressure of 2.5 Torr, the magnetic force and the force of plasma pressure are in balance with each other and the MHD activities are at their lowest level.

The birds in the collection of the Zoological Museum of the University of Liège: diversity and interest, a first approach

NARCIS (Netherlands)

Loneux, M.S.

2005-01-01

Most birds in the Liège Museum of Zoology have been collected during the 19th century. Between 1835 and 1871, Theodore Lacordaire acquired skins from South-East Asia through Francis Laporte Comte de Castelnau. Later, between 1872 and 1910, Edouard Van Beneden bought Belgian birds. At present, some

78 FR 28743 - Safety Zones; Fireworks Displays in the Sector Columbia River Captain of the Port Zone Columbia...

Science.gov (United States)

2013-05-16

... OR: May 24, 2013, from 10 p.m. until 10:30 p.m. (3) Tri-City Chamber of Commerce Fireworks Display... 4, 2013, from 10 p.m. until 10:30 p.m. (14) Arlington Chamber of Commerce Fireworks Display..., Portland, OR: August 29, 2013, from 9:30 p.m. until 10 p.m. (8) Florence Chamber 4th of July Fireworks...

Ultra-wideband ladder filters using zero-th shear mode plate wave in ultrathin LiNbO3 plate with apodized interdigital transducers

Science.gov (United States)

Kadota, Michio; Tanaka, Shuji

2016-07-01

There are two kinds of plate waves propagating in a thin plate, Lamb and shear horizontal (SH) waves. The former has a velocity higher than 15,000 m/s when the plate is very thin. On the contrary, 0th SH (SH0) mode plate wave in an ultrathin LiNbO3 plate has an electro-mechanical coupling factor larger than 50%. Authors fabricated an ultra-wideband T-type ladder filter with a relative bandwidth (BW) of 41% using the SH0 mode plate wave. Although the BW of the filter fully covers the digital TV band in Japan, it does not have sufficient margin at the lower and higher end of BW. Besides, periodic small ripples due to transverse mode in pass-band of the filter were observed. In this study π-type ladder filters were fabricated by changing the pitch ratio of interdigital transducer (IDT) of parallel and series arm resonators (PR(IDT)) to control the BW, and by apodizing IDTs to improve the periodic small ripples due to transverse mode. Ultra-wideband filters without periodic small transverse mode with ultrawide bandwidth from 41 to 49% were fabricated. The BWs fully cover ultrawide digital television bands in Japan and U.S.A. These filters with an ultrawide BW and a steep characteristic show the possibility to be applied to a reported cognitive radio system and other communication systems requiring an ultrawide BW.

Heat transfer measurements in a forced convection loop with two molten-fluoride salts: LiF--BeF2--ThF2--UF4 and eutectic NaBF4--NaF

International Nuclear Information System (INIS)

Silverman, M.D.; Huntley, W.R.; Robertson, H.E.

1976-10-01

Heat transfer coefficients were determined experimentally for two molten-fluoride salts [LiF-BeF 2 -ThF 2 -UF 4 (72-16-12-0.3 mole %) and NaBF 4 -NaF (92-8 mole %] proposed as the fuel salt and coolant salt, respectively, for molten-salt breeder reactors. Information was obtained over a wide range of variables, with salt flowing through 12.7-mm-OD (0.5-in.) Hastelloy N tubing in a forced convection loop (FCL-2b). Satisfactory agreement with the empirical Sieder-Tate correlation was obtained in the fully developed turbulent region at Reynolds moduli above 15,000 and with a modified Hausen equation in the extended transition region (Re approx.2100-15,000). Insufficient data were obtained in the laminar region to allow any conclusions to be drawn. These results indicate that the proposed salts behave as normal heat transfer fluids with an extended transition region

Electrochemical performance of LiFePO{sub 4} modified by pressure-pulsed chemical vapor infiltration in lithium-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Li Jianling [Department of Physical Chemistry, University of Science and Technology Beijing, No. 30 College Road, Haidian District, Beijing 100083 (China); Department of Applied Chemistry, Aichi Institute of Technology, Yachigusa 1247, Yakusa-cho, Toyota 470-0392 (Japan)], E-mail: lijianling@metall.ustb.edu.cn; Suzuki, Tomohiro; Naga, Kazuhisa; Ohzawa, Yoshimi; Nakajima, Tsuyoshi [Department of Applied Chemistry, Aichi Institute of Technology, Yachigusa 1247, Yakusa-cho, Toyota 470-0392 (Japan)

2007-09-25

Using the pressure-pulsed chemical vapor infiltration (PCVI) technique, pyrolytic carbon (pyrocarbon) films were deposited on the surface of LiFePO{sub 4} particles for cathode material of lithium-ion batteries. The electrochemical performance of the original LiFePO{sub 4} and PCVIed LiFePO{sub 4} materials was evaluated using a three electrodes cell by galvanostatic charging/discharging at 25, 40 and 55 deg. C, respectively. Morphology and structure of LiFePO{sub 4} were analyzed by SEM, XRD and Raman. The resulting carbon contents at 500, 1000, 2000, 3000 and 5000 pulses were 2.7, 4.7, 9.5, 15.1 and 19.4%, respectively and these samples were abbreviated as 500P, 1000P, 2000P, 3000P and 5000P, respectively. All the PCVIed samples exhibited excellent rate performance. The tendency was more and more obvious with the increase of the current densities. The specific capacities of 500P, 1000P and 2000P were maintained at 117, 124 and 132 mAh g{sup -1}, respectively, which were 120.8, 264.7 and 29.47% larger than those of corresponding original LiFePO{sub 4}, respectively, at a 5C rate at 55 deg. C. The EIS measurement showed that electrochemical reaction resistance (R{sub ct}) of PCVIed LiFePO{sub 4} were obviously decreased, indicating a fast kinetics compared to the original LiFePO{sub 4}. The cycle ability of the 2000P sample was tested at 25 deg. C and C/2 rate. The cell was cycled for 150 cycles and no obviously capacity fade was observed. Its specific capacity of 115 mAh g{sup -1} at 150th cycle is 1.7 times higher than that of original LiFePO{sub 4}.

The interstellar lithium abundance and the 7Li/6Li ratio

International Nuclear Information System (INIS)

Ferlet, R.; Dennefeld, M.

1985-01-01

The λ 6708 doublet of interstellar Li I has been observed at high spectral resolution (3.km s -1 ) and very good signal to noise ratio (∼ 4000) towards δ Sco and ζ Oph. Using a profile fitting method, we derive for the first time outside the solar system a 7 Li/ 6 Li ratio of 38 for a diffuse cloud in front of ζ Oph. Even the lower limit of the error bar is incompatible with the ratio measured in meteorites and is not explained by recent models of galactic evolution. The existence of a local inhomogeneity is suggested. Finally, as for other alkalis, lithium is depleted on to dust grains in the diffuse interstellar medium [fr

Tuning the Stability of Organic Active Materials for Nonaqueous Redox Flow Batteries via Reversible, Electrochemically Mediated Li ⁺ Coordination

Energy Technology Data Exchange (ETDEWEB)

Carino, Emily V.; Staszak-Jirkovsky, Jakub; Assary, Rajeev S.; Curtiss, Larry A.; Markovic, Nenad M.; Brushett, Fikile R.

2016-03-24

We describe an electrochemically mediated interaction between Li+ and a promising active material for nonaqueous redox flow batteries (RFBs), 1,2,3,4-tetrahydro-6,7-dimethoxy-1,1,4,4-tetramethylnaphthalene (TDT), and the impact of this structural interaction on material stability during voltammetric cycling. TDT could be an advantageous organic positive electrolyte material for nonaqueous RFBs due to its high oxidation potential, 4.21 V vs Li/Li⁺, and solubility of at least 1.0 M in select electrolytes. Although results from voltammetry suggest TDT displays Nernstian reversibility in many nonaqueous electrolyte solutions, bulk electrolysis reveals significant degradation in all electrolytes studied, the extent of which depends on the electrolyte solution composition. Results of subtractively normalized in situ Fourier transform infrared spectroscopy (SNIFTIRS) confirm that TDT undergoes reversible structural changes during cyclic voltammetry in propylene carbonate and 1,2-dimethoxyethane solutions containing Li⁺ electrolytes, but irreversible degradation occurs when tetrabutylammonium (TBA+) replaces Li⁺ as the electrolyte cation in these solutions. By combining the results from SNIFTIRS experiments with calculations from density functional theory, solution-phase active species structure and potential-dependent interactions can be determined. We find that Li⁺ coordinates to the Lewis basic methoxy groups of neutral TDT and, upon electrochemical oxidation, this complex dissociates into the radical cation TDT^•+ and Li⁺. The improved cycling stability in the presence of Li⁺ relative to TBA⁺ suggests that the structural interaction reported herein may be advantageous to the design of energy storage materials based on organic molecules.

XPS study of Li/Nb ratio in LiNbO{sub 3} crystals. Effect of polarity and mechanical processing on LiNbO{sub 3} surface chemical composition

Energy Technology Data Exchange (ETDEWEB)

Skryleva, E.A., E-mail: easkryleva@gmail.com; Kubasov, I.V., E-mail: kubasov.ilya@gmail.com; Kiryukhantsev-Korneev, Ph.V., E-mail: kiruhancev-korneev@yandex.ru; Senatulin, B.R., E-mail: borisrs@yandex.ru; Zhukov, R.N., E-mail: rom_zhuk@mail.ru; Zakutailov, K.V., E-mail: zakkonst@gmail.com; Malinkovich, M.D., E-mail: malinkovich@yandex.ru; Parkhomenko, Yu.N., E-mail: parkh@rambler.ru

2016-12-15

Highlights: • XPS Li/Nb ratio measurement uncertainty in LNbO3 specimens was obtained. • The effect of polarization on surface chemistry was observed only on cleaves. • Li/Nb ratio on positive cleave surface is higher than on negative one. • The positive cleave surface adsorbs fluorine more efficiently than negative one. • Mechanical processing of crystals reduces surface Li/Nb. - Abstract: Different sections of congruent lithium niobate (CLN) crystals have been studied using X-ray photoelectron spectroscopy (XPS). We have developed a method for measuring the lithium-to-niobium atomic ratio Li/Nb from the ratio of the Li1s and Nb4s spectral integral intensities with an overall error of within 8 %. Polarity and mechanical processing affect the Li/Nb ratio on CLN crystal surfaces. The Li/Nb ratio is within the tolerance (0.946 ± 0.074) on the negative cleave surface Z, and there is excess lithium (Li/Nb = 1.25 ± 0.10) on the positive surface. The positive surfaces of the 128° Y cut plates after long exposure to air exhibit LiOH formation indications (obvious lithium excess, higher Li1s spectral binding energy and a wide additional peak in the O1s spectrum produced by nonstructural oxygen). XPS and glow discharge optical electron spectroscopy showed that mechanical processing of differently oriented crystals (X, Z and 128° Y) and different polarities dramatically reduces the Li/Nb ratio. In situ fluorine adsorption experiments revealed the following regularities: fluorine adsorption only occurred on crystal cleaves and was not observed for mechanically processed specimens. Positive cleave surfaces have substantially higher fluorine adsorption capacity compared to negative ones.

Effect of Heat Treatment on the Lithium Ion Conduction of the LiBH4–LiI Solid Solution

DEFF Research Database (Denmark)

Sveinbjörnsson, Dadi Þorsteinn; Mýrdal, Jón Steinar Garðarsson; Blanchard, Didier

2013-01-01

The LiBH4–LiI solid solution is a good Li+ conductor and a promising crystalline electrolyte for all-solid-state lithium based batteries. The focus of the present work is on the effect of heat treatment on the Li+ conduction. Solid solutions with a LiI content of 6.25–50% were synthesized by high...

Freeze-drying synthesis of three-dimensional porous LiFePO4 modified with well-dispersed nitrogen-doped carbon nanotubes for high-performance lithium-ion batteries

International Nuclear Information System (INIS)

Tu, Xiaofeng; Zhou, Yingke; Song, Yijie

2017-01-01

Highlights: • Three-dimensional porous LiFePO 4 /N-CNTs is synthesized by a freeze-drying method. • The N-CNTs conductive network enhances the electron transport within the LiFePO 4 electrode. • The continuous pores accelerate the diffusion of lithium ions. • LiFePO 4 /N-CNTs demonstrates an excellent electrochemical Li-insertion performance. - Abstract: The three-dimensional porous LiFePO 4 modified with uniformly dispersed nitrogen-doped carbon nanotubes has been successfully prepared by a freeze-drying method. The morphology and structure of the porous composites are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), and the electrochemical performances are evaluated using the constant current charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy. The nitrogen-doped carbon nanotubes are uniformly dispersed inside the porous LiFePO 4 to construct a superior three-dimensional conductive network, which remarkably increases the electronic conductivity and accelerates the diffusion of lithium ion. The porous composite displays high specific capacity, good rate capability and excellent cycling stability, rendering it a promising positive electrode material for high-performance lithium-ion batteries.

Density functional theory study of lithium diffusion at the interface between olivine-type LiFePO4 and LiMnPO4

Science.gov (United States)

Shi, Jianjian; Wang, Zhiguo; Qing Fu, Yong

2016-12-01

Coating LiMnPO4 with a thin layer of LiFePO4 shows a better electrochemical performance than the pure LiFePO4 and LiMnPO4, thus it is critical to understand Li diffusion at their interfaces to improve the performance of electrode materials. Li diffusion at the (1 0 0)\\text{LiFeP{{\\text{O}}4}} //(1 0 0)\\text{LiMnP{{\\text{O}}4}} , (0 1 0)\\text{LiFeP{{\\text{O}}4}} //(0 1 0)\\text{LiMnP{{\\text{O}}4}} , and (0 0 1)\\text{LiFeP{{\\text{O}}4}} //(0 0 1)\\text{LiMnP{{\\text{O}}4}} interfaces between LiFePO4 and LiMnPO4 was investigated using density functional theory. The calculated diffusion energy barriers are 0.55 eV for Li to diffuse along the (0 0 1) interface, 0.44 and 0.49 eV for the Li diffusion inside the LiMnPO4 and along the (1 0 0) interface, respectively. When Li diffuses from the LiFePO4 to LiMnPO4 by passing through the (0 1 0) interfaces, the diffusion barriers are 0.45 and 0.60 eV for the Li diffusions in both sides. The diffusion barriers for Li to diffuse in LiMnPO4 near the interfaces decrease compared with those in the pure LiMnPO4. The calculated diffusion coefficient of Li along the (1 0 0) interface is in the range of 3.65  ×  10-11-5.28  ×  10-12 cm2 s-1, which is larger than that in the pure LiMnPO4 with a value of 7.5  ×  10-14 cm2 s-1. Therefore, the charging/discharging rate performance of the LiMnPO4 can be improved by surface coating with the LiFePO4.

An insight into intrinsic interfacial properties between Li metals and Li10GeP2S12 solid electrolytes.

Science.gov (United States)

Chen, Bingbing; Ju, Jiangwei; Ma, Jun; Zhang, Jianjun; Xiao, Ruijuan; Cui, Guanglei; Chen, Liquan

2017-11-29

Density functional theory simulations and experimental studies were performed to investigate the interfacial properties, including lithium ion migration kinetics, between lithium metal anode and solid electrolyte Li 10 GeP 2 S 12 (LGPS). The LGPS[001] plane was chosen as the studied surface because the easiest Li + migration pathway is along this direction. The electronic structure of the surface states indicated that the electrochemical stability was reduced at both the PS 4 - and GeS 4 -teminated surfaces. For the interface cases, the equilibrium interfacial structures of lithium metal against the PS 4 -terminated LGPS[001] surface (Li/PS 4 -LGPS) and the GeS 4 -terminated LGPS[001] surface (Li/GeS 4 -LGPS) were revealed based on the structural relaxation and adhesion energy analysis. Solid electrolyte interphases were expected to be formed at both Li/PS 4 -LGPS and Li/GeS 4 -LGPS interfaces, resulting in an unstable state of interface and large interfacial resistance, which was verified by the EIS results of the Li/LGPS/Li cell. In addition, the simulations of the migration kinetics show that the energy barriers for Li + crossing the Li/GeS 4 -LGPS interface were relatively low compared with the Li/PS 4 -LGPS interface. This may contribute to the formation of Ge-rich phases at the Li/LGPS interface, which can tune the interfacial structures to improve the ionic conductivity for future all-solid-state batteries. This work will offer a thorough understanding of the Li/LGPS interface, including local structures, electronic states and Li + diffusion behaviors in all-solid-state batteries.

LiNi1/3Co1/3Mn1/3O2 nanoplates with {010} active planes exposing prepared in polyol medium as a high-performance cathode for Li-ion battery.

Science.gov (United States)

Li, Jili; Yao, Ruimin; Cao, Chuanbao

2014-04-09

As we know, Li(+)-ion transport in layered LiNi1/3Co1/3Mn1/3O2 (NCM) is through two-dimensional channels parallel to the Li(+)-ion layers that are indexed as {010} active planes. In this paper, NCM nanoplates with exposed {010} active facets are synthesized in a polyol medium (ethylene glycol) and characterized by XRD, XPS, SEM, and HR-TEM. In addition, the effects of reaction conditions on the morphologies, structures and electrochemical performances are also evaluated. The results show that more {010} facets can be exposed with the thickness of NCM nanoplates increasing which can lead to more channels for Li(+)-ion migration. However, when the annealing temperatures exceed 900 °C, many new crystal planes grow along the thickness direction covering the {010} facets. In all of the NCM nanoplates obtained at different conditions, the NCM nanoplates calcined at 850 °C for 12 h (NCM-850-12H) display a high initial discharge capacity of 207.6 mAh g(-1) at 0.1 C (1 C = 200 mA g(-1)) between 2.5 and 4.5 V higher than most of NCM materials as cathodes for lithium ion batteries. The discharge capacities of NCM-850-12H are 169.8, 160.5, and 149.3 mAh g(-1) at 2, 5, and 7 C, respectively, illustrating the excellent rate capability. The superior electrochemical performance of NCM-850-12H cathode can be attributed to more {010} active planes exposure.

Relaxation-phenomena in LiAl/FeS-cells

Science.gov (United States)

Borger, W.; Kappus, W.; Panesar, H. S.

A theoretical model of the capacity of strongly relaxing electrochemical systems is applied to the LiAl/FeS system. Relaxation phenomena in LiAl and FeS electrodes can be described by this model. Experimental relaxation data indicate that lithium transport through the alpha-LiAl layer to the particle surface is the capacity limiting process at high discharge current density in the LiAl electrode in LiCl-KCl and LiF-LiCl-LiBr mixtures. Strong relaxation is observed in the FeS electrode with LiCl-KCl electrolyte caused by lithium concentration gradients and precipitation of KCl in the pores.

Measurement of the neutron capture cross-section of 232Th using the neutron activation technique

International Nuclear Information System (INIS)

Naik, H.; Singh, Sarbjit; Goswami, A.; Manchanda, V.K.; Prajapati, P.M.; Surayanarayana, S.V.; Nayak, B.K.; Sharma, S.C.; Jagadeesan, K.C.; Thakare, S.V.; Raj, D.; Ganesan, S.; Mulik, V.K.; Sivashankar, B.S.; Mukherjee, S.

2011-01-01

The 232 Th(n, γ) reaction cross-section at average neutron energies of 3.7±0.3 MeV and 9.85±0.38 MeV from the 7 Li(p, n) reaction has been determined for the first time using activation and off-line γ -ray spectrometric technique. The 232 Th(n, 2n) reaction cross-section at the average neutron energy of 9.85±0.38 MeV has been also determined using the same technique. The experimentally determined 232 Th(n, γ) and 232 Th(n, 2n) reaction cross-sections were compared with the evaluated data of ENDF/B-VII, JENDL-4.0 and JEFF-3.1 and were found to be in good agreement. The present data along with literature data in a wide range of neutron energies were interpreted in terms of competition between different reaction channels including fission. The 232 Th(n, γ) and 232 Th(n, 2n) reaction cross-sections were also calculated theoretically using the TALYS 1.2 computer code and were found to be slightly higher than the experimental data. (orig.)

Charge carrier density in Li-intercalated graphene

KAUST Repository

Kaloni, Thaneshwor P.

2012-05-01

The electronic structures of bulk C 6Li, Li-intercalated free-standing bilayer graphene, and Li-intercalated bilayer and trilayer graphene on SiC(0 0 0 1) are studied using density functional theory. Our estimate of Young\\'s modulus suggests that Li-intercalation increases the intrinsic stiffness. For decreasing Li-C interaction, the Dirac point shifts to the Fermi level and the associated band splitting vanishes. For Li-intercalated bilayer graphene on SiC(0 0 0 1) the splitting at the Dirac point is tiny. It is also very small at the two Dirac points of Li-intercalated trilayer graphene on SiC(0 0 0 1). For all the systems under study, a large enhancement of the charge carrier density is achieved by Li intercalation. © 2012 Elsevier B.V. All rights reserved.

Probing the failure mechanism of nanoscale LiFePO4 for Li-ion batteries

International Nuclear Information System (INIS)

Gu, Meng; Yan, Pengfei; Wang, Chongmin; Shi, Wei; Zheng, Jianming; Zhang, Ji-guang

2015-01-01

LiFePO 4 is a high power rate cathode material for lithium ion battery and shows remarkable capacity retention, featuring a 91% capacity retention after 3300 cycles. In this work, we use high-resolution transmission electron microscopy and electron energy loss spectroscopy to study the gradual capacity fading mechanism of LiFePO 4 materials. We found that upon prolonged electrochemical cycling of the battery, the LiFePO 4 cathode shows surface amorphization and loss of oxygen species, which directly contribute to the gradual capacity fading of the battery. The finding can guide the design and improvement of LiFePO 4 cathode for high-energy and high-power rechargeable battery for electric transportation

3D display system using monocular multiview displays

Science.gov (United States)

Sakamoto, Kunio; Saruta, Kazuki; Takeda, Kazutoki

2002-05-01

A 3D head mounted display (HMD) system is useful for constructing a virtual space. The authors have researched the virtual-reality systems connected with computer networks for real-time remote control and developed a low-priced real-time 3D display for building these systems. We developed a 3D HMD system using monocular multi-view displays. The 3D displaying technique of this monocular multi-view display is based on the concept of the super multi-view proposed by Kajiki at TAO (Telecommunications Advancement Organization of Japan) in 1996. Our 3D HMD has two monocular multi-view displays (used as a visual display unit) in order to display a picture to the left eye and the right eye. The left and right images are a pair of stereoscopic images for the left and right eyes, then stereoscopic 3D images are observed.

2009 Puget Sound LiDAR Consortium (PSLC) Topographic LiDAR: Lewis County, Washington

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Watershed Sciences, Inc. (WSI) collected Light Detection and Ranging (LiDAR) data for the Lewis County survey area for the Puget Sound LiDAR Consortium. This data...

Evaluation of Li3N accumulation in a fused LiCl/Li salt matrix

International Nuclear Information System (INIS)

Eberle, C. S.

1998-01-01

Pyrochemical conditioning of spent nuclear fuel for the purpose of final disposal is currently being demonstrated at Argonne National Laboratory (ANL), and ongoing research in this area includes the demonstration of this process on spent oxide fuel. In conjunction with this research a pilot scale of the preprocessing stage is being designed by ANL-W to demonstrate the in situ hot cell capability of the chemical reduction stage. An impurity evaluation was completed for a Li/LiCl salt matrix in the presence of spent LWR uranium oxide fuel. A simple analysis was performed in which the sources of impurities in the salt matrix were only from the cell atmosphere. Only reactions with the lithium were considered. The levels of impurities were shown to be highly sensitive system conditions. A predominance diagram for the Li-O-N system was constructed for the device, and the general oxidation, nitridation and combined reactions were calculated as a function of oxygen and nitrogen partial pressure. These calculations and hotcell atmosphere data were used to determine the total number and type of impurities expected in the salt matrix and the mass rate for the device was determined

Protons scattering on Li isotopes at intermediate energies

International Nuclear Information System (INIS)

Zhusupov, M.A.; Imambekov, O.; Sanfirova, A.V.; Ibraeva, E.T.

2003-01-01

The protons scattering differential cross section on the 6,7,8 Li nuclei are calculated within the framework the Glauber-Sitenko multiple scattering theory at intermediate energies (from 100 to 1000 MeV). In the calculations the multi-cluster wave functions (αt for 7 Li, αnp for 6 Li, and αtn for 8 Li) considering within potential cluster model have been used. Differential cross sections for 6 Li, 7 Li, 8 Li and 9 Li nuclei are similar: absolute cross sections are almost the same, diffraction minimum for large A shifting to the field of the least scattering angles that reflecting increase of the material radius. For the 11 Li the differential cross section absolute value is smaller about in two time than for the rest isotopes. At present it is reliably established, that the 11 Li nucleus has an exotic structure - the nine-nucleon core ( 9 Li) around which the two-neutron halo is rotating. The principal characteristics of the Li nuclei are presented in tabular form

Composited reduced graphene oxide into LiFePO4/Li2SiO3 and its electrochemical impedance spectroscopy properties

Science.gov (United States)

Arifin, M.; Rus, Y. B.; Aimon, A. H.; Iskandar, F.; Winata, T.; Abdullah, M.; Khairurrijal, K.

2017-03-01

LiFePO4 is commonly used as cathode material for Li-ion batteries due to its stable operational voltage and high specific capacity. However, it suffers from certain disadvantages such as low intrinsic electronic conductivity and low ionic diffusion. This study was conducted to analyse the effect of reduced graphene oxide (rGO) on the electrochemical properties of LiFePO4/Li2SiO3 composite. This composite was synthesized by a hydrothermal method. Fourier transform infrared spectroscopy measurement identified the O-P-O, Fe-O, P-O, and O-Si-O- bands in the LiFePO4/Li2SiO3 composite. X-ray diffraction measurement confirmed the formation of LiFePO4. Meanwhile, Raman spectroscopy confirmed the number of rGO layers. Further, scanning electron microscopy images showed that rGO was distributed around the LiFePO4/Li2SiO3 particles. Finally, the electrochemical impedance spectroscopy results showed that the addition of 1 wt% of rGO to the LiFePO4/Li2SiO3 composite reduced charge transfer resistance. It may be concluded that the addition of 1 wt% rGO to LiFePO4/Li2SiO3 composite can enhance its electrochemical performance as a cathode material.

Improved Dehydrogenation Properties of 2LiNH2-MgH2 by Doping with Li3AlH6

Directory of Open Access Journals (Sweden)

Shujun Qiu

2017-01-01

Full Text Available Doping with additives in a Li-Mg-N-H system has been regarded as one of the most effective methods of improving hydrogen storage properties. In this paper, we prepared Li3AlH6 and evaluated its effect on the dehydrogenation properties of 2LiNH2-MgH2. Our studies show that doping with Li3AlH6 could effectively lower the dehydrogenation temperatures and increase the hydrogen content of 2LiNH2-MgH2. For example, 2LiNH2-MgH2-0.1Li3AlH6 can desorb 6.43 wt % of hydrogen upon heating to 300 °C, with the onset dehydrogenation temperature at 78 °C. Isothermal dehydrogenation testing indicated that 2LiNH2-MgH2-0.1Li3AlH6 had superior dehydrogenation kinetics at low temperature. Moreover, the release of byproduct NH3 was successfully suppressed. Measurement of the thermal diffusivity suggests that the enhanced dehydrogenation properties may be ascribed to the fact that doping with Li3AlH6 could improve the heat transfer for solid–solid reaction.

Avionics Interface Data Summaries: A-10A, EF-111A, F-4E, F-4G, F-15A, F- 16A, F-111A, F-111E, F-111F, RF-4C

Science.gov (United States)

1979-10-01

producing an error signal "nc:t•:.; that a" invalid verd has beer -eceived. h.2.2 f•rLn•5-Irt1 M4ole - When operating in the transmitting mode, the...ES Gose 0 kint SCALE FACTOR: J * I RESOLUTIOiN: (TBOo1) Electrical Chrarte-i’stics (Continued on next page) SOURCE: Aux1li:ry Flight Reference System

Charge carrier density in Li-intercalated graphene

KAUST Repository

Kaloni, Thaneshwor P.; Cheng, Yingchun; Kahaly, M. Upadhyay; Schwingenschlö gl, Udo

2012-01-01

The electronic structures of bulk C 6Li, Li-intercalated free-standing bilayer graphene, and Li-intercalated bilayer and trilayer graphene on SiC(0 0 0 1) are studied using density functional theory. Our estimate of Young's modulus suggests that Li

Investigation of interfacial resistance between LiCoO{sub 2} cathode and LiPON electrolyte in the thin film battery

Energy Technology Data Exchange (ETDEWEB)

Jeong, Eunkyung; Hong, Chan; Tak, Yongsug [Department of Chemical Engineering, Inha University, Inchon 402-751 (Korea, Republic of); Nam, Sang Cheol [Nuricell Inc., Jungrang-Ku, Seoul 131-220 (Korea, Republic of); Cho, Sungbaek [Agency for Defense Development, P.O. Box 35, Daejeon (Korea, Republic of)

2006-09-13

All solid-state thin film battery was prepared with conventional sputtering technologies. Low conductivity of lithium phosphorus oxynitride (LiPON) electrolyte and higher resistance at the interface of LiCoO{sub 2}/LiPON was crucial for the development of thin film battery. Presence of thermally treated Al{sub 2}O{sub 3} thin film at the interface of LiCoO{sub 2}/LiPON decreased the interfacial resistance and increased the discharge capacity with the better cycling behaviors. Surface analysis and electrochemical impedance measurement indicate the formation of solid solution LiCo{sub 1-y}Al{sub y}O{sub 2} at the interface of LiCoO{sub 2}/LiPON. (author)

Li{sub 4}SiO{sub 4} based breeder ceramics with Li{sub 2}TiO{sub 3}, LiAlO{sub 2} and Li{sub X}La{sub Y}TiO{sub 3} additions, part II: Pebble properties

Energy Technology Data Exchange (ETDEWEB)

Kolb, M.H.H., E-mail: Matthias.kolb@kit.edu [Karlsruhe Institute of Technology, Institute for Applied Materials, PO Box 3640, 76021, Karlsruhe (Germany); Knitter, R. [Karlsruhe Institute of Technology, Institute for Applied Materials, PO Box 3640, 76021, Karlsruhe (Germany); Hoshino, T. [Breeding Functional Materials Development Group, Department of Blanket Systems Research, Rokkasho Fusion Institute, Fusion Energy Research and Development Directorate, National Institutes for Quantum and Radiological Science and Technology (QST) (Japan)

2017-02-15

Highlights: • The mechanical strength of Li{sub 4}SiO{sub 4}-based breeder pebbles can be improved by adding either LMT, LAO or LLTO as second phase. • The increase in strength is closely linked to a reduction of the open porosity of the pebbles. • All fabricated pebbles show a highly homogenous microstructure with mostly low closed porosity. • Adding LLTO, although it decomposes during sintering, greatly improves the strength of the pebbles. - Abstract: The pebble properties of novel two-phase Li{sub 4}SiO{sub 4} pebbles of 1 mm diameter with additions of Li{sub 2}TiO{sub 3}, LiAlO{sub 2} or Li{sub x}La{sub y}TiO{sub 3} are evaluated in this work as a function of the second phase concentration and the microstructure of the pebbles. The characterization focused on the mechanical strength, microstructure and open as well as closed porosity. Therefore crush load tests, SEM analyses as well as helium pycnometry and optical image analysis were performed, respectively. This work shows that generally additions of a second phase to Li{sub 4}SiO{sub 4} considerably improve the mechanical strength. It also shows that the fabrication processes have to be well-controlled to achieve high mechanical strengths. When Li{sub 2}TiO{sub 3} is added in different concentrations, the determinant for the crush load seems to be the open porosity of the pebbles. The strengthening effect of LiAlO{sub 2} compared to Li{sub 2}TiO{sub 3} is similar, while additions of Li{sub x}La{sub y}TiO{sub 3} increase the mechanical strength much more. Yet, Li{sub 4}SiO{sub 4} and Li{sub x}La{sub y}TiO{sub 3} react with each other to a number of different phases upon sintering. In general the pebble properties of all samples are favorable for use within a fusion breeder blanket.

Capturing and Processing Soil GHG Fluxes Using the LI-COR LI-8100A

Science.gov (United States)

Xu, Liukang; McDermitt, Dayle; Hupp, Jason; Johnson, Mark; Madsen, Rod

2015-04-01

The LI-COR LI-8100A Automated Soil CO2 Flux System is designed to measure soil CO2 efflux using automated chambers and a non-steady state measurement protocol. While CO2 is an important gas in many contexts, it is not the only gas of interest for many research applications. With some simple plumbing modifications, many third party analyzers capable of measuring other trace gases, e.g. N2O, CH4, or 13CO2 etc., can be interfaced with the LI-8100A System, and LI-COR's data processing software (SoilFluxPro™) can be used to compute fluxes for these additional gases. In this paper we describe considerations for selecting an appropriate third party analyzer to interface with the system, how to integrate data into the system, and the procedure used to compute fluxes of additional gases in SoilFluxPro™. A case study is presented to demonstrate methane flux measurements using an Ultra-Portable Greenhouse Gas Analyzer (Ultra-Portable GGA, model 915-0011), manufactured by Los Gatos Research and integrated into the LI-8100A System. Laboratory and field test results show that the soil CO2 efflux based on the time series of CO2 data measured either with the LI-8100A System or with the Ultra-Portable GGA are essentially the same. This suggests that soil GHG fluxes measured with both systems are reliable.

Microstructure Analysis of Synthesized LiBOB

Directory of Open Access Journals (Sweden)

Etty Marti Wigayati

2015-11-01

Full Text Available Lithium bis (oxalate borate or LiBOB is an active material used as the electrolyte for lithium battery application. LiBOB (LiB(C2O42 powder was prepared from LiOH, H2C2O4 and H3BO3. The employed method was solid state reaction. LiBOB powder produced from the reaction was then observed using SEM and TEM. Surface area was analyzed using Quantachrome Nova 4200e. From the analysis analyzed using XRD to identify the resulting phases, crystal structure, and crystallite size. The functional groups were analyzed using FT-IR. The particle morphology was result, it was seen that the resulted phases were C4LiBO8 and LiB(C2O42.H2O, the crystal structure was orthorhombic with space group Pbca and Pnma. From the particle morphology observation it was shown that micro pores were created irregularly. When the observation was deepened, nanopores with elongated round shape were seen within the micropores. The pore size was approximately 50–100 nm. The surface area, total pore volume, and average pore diameter of LiBOB powder was 88.556 m2/g, 0.4252 cm3/g, and 19.2 nm respectively.

Li4SiO4-Based Artificial Passivation Thin Film for Improving Interfacial Stability of Li Metal Anodes.

Science.gov (United States)

Kim, Ji Young; Kim, A-Young; Liu, Guicheng; Woo, Jae-Young; Kim, Hansung; Lee, Joong Kee

2018-03-14

An amorphous SiO 2 (a-SiO 2 ) thin film was developed as an artificial passivation layer to stabilize Li metal anodes during electrochemical reactions. The thin film was prepared using an electron cyclotron resonance-chemical vapor deposition apparatus. The obtained passivation layer has a hierarchical structure, which is composed of lithium silicide, lithiated silicon oxide, and a-SiO 2 . The thickness of the a-SiO 2 passivation layer could be varied by changing the processing time, whereas that of the lithium silicide and lithiated silicon oxide layers was almost constant. During cycling, the surface of the a-SiO 2 passivation layer is converted into lithium silicate (Li 4 SiO 4 ), and the portion of Li 4 SiO 4 depends on the thickness of a-SiO 2 . A minimum overpotential of 21.7 mV was observed at the Li metal electrode at a current density of 3 mA cm -2 with flat voltage profiles, when an a-SiO 2 passivation layer of 92.5 nm was used. The Li metal with this optimized thin passivation layer also showed the lowest charge-transfer resistance (3.948 Ω cm) and the highest Li ion diffusivity (7.06 × 10 -14 cm 2 s -1 ) after cycling in a Li-S battery. The existence of the Li 4 SiO 4 artificial passivation layer prevents the corrosion of Li metal by suppressing Li dendritic growth and improving the ionic conductivity, which contribute to the low charge-transfer resistance and high Li ion diffusivity of the electrode.

Highly stable bilayer of LiPON and B2O3 added Li1.5Al0.5Ge1.5(PO4) solid electrolytes for non-aqueous rechargeable Li-O2 batteries

International Nuclear Information System (INIS)

Jadhav, Harsharaj S.; Kalubarme, Ramchandra S.; Jadhav, Arvind H.; Seo, Jeong Gil

2016-01-01

Highlights: • LiPON thin film deposited by RF-sputtering technique. • The effect of deposition temperature on ionic conductivity was investigated. • The LiPON/B-LAGP composite was successfully employed in Li-O 2 battery. • LiPON interlayer enhances stability of B-LAGP in contact with Li-metal. - Abstract: Lithium ion conducting membranes are barely studied, although they are essentially indispensable for building Li-air batteries composed of aqueous and non-aqueous electrolytes for long-term operation. Lithium phosphorous oxynitride (LiPON) thin films were deposited by RF-sputtering technique on B 2 O 3 -added lithium aluminum germanium phosphate (B-LAGP). Compact thin amorphous LiPON layer could act as a protective interlayer for B-LAGP by separating it from Li metal electrode and mitigate the reaction between them. Large electrochemical stability window (0–5 V) of LiPON/B-LAGP solid electrolyte shows promising feasibility for applications in all lithium based batteries. The aprotic Li-O 2 cell with protected lithium electrode configuration employing LiPON/B-LAGP solid electrolyte has exhibited reasonable cycling stability with long-life of 52 cycles at a limited capacity of 1000 mA h g −1 .

Probing the failure mechanism of nanoscale LiFePO₄ for Li-ion batteries

Energy Technology Data Exchange (ETDEWEB)

Gu, Meng [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL); Shi, Wei [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Energy and Environmental Directorate; Beijing Jiaotong University (China). School of Electrical Engineering, National Active Distribution Network Technology Research Center; Zheng, Jianming [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Energy and Environmental Directorate; Yan, Pengfei [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL); Zhang, Ji-guang [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Energy and Environmental Directorate; Wang, Chongmin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)

2015-05-18

LiFePO₄ is a high power rate cathode material for lithium ion battery and shows remarkable capacity retention, featuring a 91% capacity retention after 3300 cycles. In this work, we use high-resolution transmission electron microscopy (HRTEM), energy dispersive x-ray spectroscopy (EDS), and electron energy loss spectroscopy (EELS) to study the gradual capacity fading mechanism of LiFePO₄ materials. We found that upon prolonged electrochemical cycling of the battery, the LiFePO₄ cathode shows surface amorphization and loss of oxygen species, which directly contribute to the gradual capacity fading of the battery. The finding is of great importance for the design and improvement of new LiFePO₄ cathode for high-energy and high-power rechargeable battery for electric transportation.

The effect of Li2CO3 substitution on synthesis of LiBOB compounds as salt of electrolyte battery lithium ion

Science.gov (United States)

Lestariningsih, Titik; Wigayati, Etty Marty; Sabrina, Qolby; Prihandoko, Bambang; Priyono, Slamet

2018-04-01

Development of the synthesis of LiB(C2O4)2 compounds continues to evolve along with the need for electrolyte salts to support the research of the manufacture of lithium ion batteries. A study had been conducted on the effect of Li2CO3 substitution on the synthesis of LiB(C2O4)2 or LiBOB compounds. LiBOB was a major candidate to replace LiPF6 as a highly toxic lithium battery electrolyte and harmful to human health. Synthesis of Lithium bis(oxalato) borate used powder metallurgy method. The raw materials used are H2C2O4.2H2O, Li2CO3 or LiOH and H2BO3 from Merck Germany products. The materials are mixed with 2: 1: 1 mol ratio until homogeneous. The synthesis of LiBOB refers to previous research, where the heating process was done gradually. The first stage heating is carried out at 120°C for 4 hours, then the next stage heating is carried out at 240°C for 7 hours. The sample variation in this study was to distinguish the lithium source from Li2CO3 and LiOH. Characterization was done by XRD to know the phase formed, FTIR to confirm that functional group of LiB(C2O4)2 compound, SEM to know the morphological structure, and TG/DTA to know the thermal properties. The results of the analysis shows that LiBOB synthesis using Lithium source from Li2CO3 has succeeded to form LiBOB compound with more LiBOB phase composition is 59.1% and 40.9% LiBOB hydrate phase, SEM morphology shows powder consist of elongated round particle porous and similar to LiBOB commercial and show higher thermal stability.

Li{sub 4}SiO{sub 4} based breeder ceramics with Li{sub 2}TiO{sub 3}, LiAlO{sub 2} and Li{sub X}La{sub Y}TiO{sub 3} additions, part I: Fabrication

Energy Technology Data Exchange (ETDEWEB)

Kolb, M.H.H., E-mail: Matthias.kolb@kit.edu [Karlsruhe Institute of Technology, Institute for Applied Materials, PO Box 3640, 76021 Karlsruhe (Germany); Mukai, K.; Knitter, R. [Karlsruhe Institute of Technology, Institute for Applied Materials, PO Box 3640, 76021 Karlsruhe (Germany); Hoshino, T. [Breeding Functional Materials Development Group, Department of Blanket Systems Research, Rokkasho Fusion Institute, Fusion Energy Research and Development Directorate, National Institutes for Quantum and Radiological Science and Technology (QST) (Japan)

2017-02-15

Highlights: • This study shows that the emulsion method can easily be adapted to add different phases into Li4SiO4 breeder pebbles. • Slurries with various compositions to form LOS + LMT, LOS + LAO and LOS + LLTO were processed.The calculated activation behavior shows that samples with added LAO or LLTO qualify as low activation material. • Yet, the long-term activation of the LAO containing samples is problematic as hands-on level activity is not reached quickly. - Abstract: Wet-chemical fabrication processes are highly adaptable to a wide range of raw materials and are therefore well suited for evaluating new material compositions. Here the established emulsion method was modified to fabricate novel two-phase Li{sub 4}SiO{sub 4} pebbles of 1 mm diameter with additions of Li{sub 2}TiO{sub 3}, LiAlO{sub 2} or Li{sub x}La{sub y}TiO{sub 3}. As the lithium density of the latter two compounds is relatively low, only moderate contents were added. The Li{sub 2}TiO{sub 3} additions, however, cover the full compositional range. The fabrication process was characterized with regard to its constancy and aptness for the anticipated pebble compositions by optical pebble size measurements. Also the phase content and the elemental composition of the fabricated pebbles were analyzed by XRD and ICP-OES combined with XRF, respectively. This work shows that the emulsion method is an appropriate method to produce pebbles with the anticipated Li{sub 2}TiO{sub 3} and LiAlO{sub 2} concentrations in a Li{sub 4}SiO{sub 4} matrix. However, Li{sub 4}SiO{sub 4} and Li{sub x}La{sub y}TiO{sub 3} react with each other to a number of different phases. To evaluate the activation properties of the pebbles, FISPACT calculations with a DEMO relevant neutron source are applied as well. The addition of aluminum seems to be unfavorable for a fusion application, but moderate concentrations of lanthanum can be tolerated.

77 FR 48431 - Safety Zone for Fireworks Display, Pamlico and Tar Rivers; Washington, NC

Science.gov (United States)

2012-08-14

... near the Pamlico and Tar Rivers to commemorate Beaufort County's 300th anniversary. The temporary... 1625-AA00 Safety Zone for Fireworks Display, Pamlico and Tar Rivers; Washington, NC AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a temporary safety zone on...

Synthesis of One Dimensional Li2MoO4 Nanostructures and Their Electrochemical Performance as Anode Materials for Lithium-ion Batteries

International Nuclear Information System (INIS)

Liu, Xudong; Zhao, Yanming; Dong, Youzhong; Fan, Qinghua; Kuang, Quan; Liang, Zhiyong; Lin, Xinghao; Han, Wei; Li, Qidong; Wen, Mingming

2015-01-01

Highlights: • One dimensional Li 2 MoO 4 nanostructures including nanorods and nanotubes have been successfully fabricated via a simple sol-gel method firstly. • Possible crystal formation mechanisms are proposed for these one dimensional Li 2 MoO 4 nanostructures. • These one dimensional Li 2 MoO 4 nanostructure electrode materials present outstanding rate abilities and cycle capabilities in electrochemical performance compared to the carbon-free powder sample when evaluated as anode materials for Lithium-ion batteries. • The carbon-coated Li 2 MoO 4 nanotube electrode improves the charging/discharging capacities of graphite even after applying 60 cycles at very high current density. - Abstract: One dimensional Li 2 MoO 4 nanostructures including nanorods and nanotubes have been successfully fabricated via a simple sol-gel method adding Li 2 CO 3 and MoO 3 powders into distilled water with citric acid as an assistant agent and carbon source. Our experimental results show that the formation of the one dimensional nanostructure morphology is evaporation and crystallization process with self-adjusting into a rod-like hexagonal cross-section structure, while the citric acid played an important role during the formation of Li 2 MoO 4 nanotubes under the acidic environment by capping, stabilizing the {1010} facet of Li 2 MoO 4 structure and controlling the concentration of H + (pH value) of the aqueous solution. Finally, basic electrochemical performance of these one dimensional Li 2 MoO 4 nanostructures including nanorods and nanotubes evaluated as anode materials for lithium-ion batteries (LIBs) are discussed, for comparison, the properties of carbon-free powder sample synthesized by solid-state reaction are also displayed. Experimental results show that different morphology and carbon-coating on the surface have an important influence on electrochemical performance

Li{sub 2}MnSiO{sub 4} as a potential Li-battery cathode material

Energy Technology Data Exchange (ETDEWEB)

Dominko, R.; Bele, M.; Gaberscek, M.; Jamnik, J. [National Institute of Chemistry, P.O.B. 660, SI-1001 Ljubljana (Slovenia); Kokalj, A. [Institute Jozef Stefan, Jamova 39, SI-1000 Ljubljana (Slovenia)

2007-12-06

Recently we synthesized and preliminary characterized a new material for potential use in Li-battery cathodes: Li{sub 2}MnSiO{sub 4}. Although its theoretical capacity is about 330 mAh g{sup -1}, the actual measurements showed a much smaller value (about 120 mAh g{sup -1}). One of the reasons for the poor performance could be the poor electronic conductivity (<10{sup -14} S cm{sup -1} at RT) causing a huge polarization during charge-discharge. However, in the present paper we show that reducing the particle size down to the range of 20-50 nm and additional particle embedment into a carbon phase does not significantly improve the electrochemistry of Li{sub 2}MnSiO{sub 4}. Observations of structural changes during the first charge shows a complete loss of peaks when reaching the nominal composition of ca. Li{sub 1}MnSiO{sub 4}. The peaks are not recovered during subsequent cycling. It is supposed that extraction of Li causes significant structural changes so that the resulting material is only able to reversibly exchange a limited amount of Li. (author)

An item response theory analysis of the Olweus Bullying scale.

Science.gov (United States)

Breivik, Kyrre; Olweus, Dan

2014-12-02

In the present article, we used IRT (graded response) modeling as a useful technology for a detailed and refined study of the psychometric properties of the various items of the Olweus Bullying scale and the scale itself. The sample consisted of a very large number of Norwegian 4th-10th grade students (n = 48 926). The IRT analyses revealed that the scale was essentially unidimensional and had excellent reliability in the upper ranges of the latent bullying tendency trait, as intended and desired. Gender DIF effects were identified with regard to girls' use of indirect bullying by social exclusion and boys' use of physical bullying by hitting and kicking but these effects were small and worked in opposite directions, having negligible effects at the scale level. Also scale scores adjusted for DIF effects differed very little from non-adjusted scores. In conclusion, the empirical data were well characterized by the chosen IRT model and the Olweus Bullying scale was considered well suited for the conduct of fair and reliable comparisons involving different gender-age groups. Information Aggr. Behav. 9999:XX-XX, 2014. © 2014 Wiley Periodicals, Inc. © 2014 Wiley Periodicals, Inc.

Synthesis and characterization of nano- and microcrystalline cubes of pure and Ag-doped LiF

Science.gov (United States)

Alharbi, Najlaa D.; Salah, Numan; Habib, Sami S.; Alarfaj, Esam

2013-01-01

Lithium fluoride (LiF) produced in single crystals and doped with proper activators is a highly sensitive phosphor used in several applications such as integrated optics, colour centre laser and radiation dosimetry. In this work, we have developed a new synthetic chemical co-precipitation route for the synthesis of well-crystallized micro- and nanocrystalline cubes of pure and silver (Ag)-doped LiF. The as-synthesized samples were characterized by x-ray diffraction (XRD), scanning electron microscopy, absorption spectrum, photoluminescence (PL) and Raman spectroscopy. Size of the produced cubes could be controlled in the range 10 µm-50 nm by varying the solvent : co-solvent ratio. Micro-sized cubes could be grown in the presence of water as a solvent, while ethanol, which acts as a co-solvent, is found to be effective in reducing the size to the nanoscale. XRD results show complete crystalline structures in a griceite phase. The PL result of pure nanocubes exhibits a broad band in the range 370-550 nm, while that doped with Ag shows a prominent band at 420 nm. Raman spectra of the pure and Ag-doped LiF samples display several bands located in the range 80-236 cm-1. These results show that pure nanocubes of LiF have active colour centres without irradiation, which could be enhanced/modified by Ag dopants. This implies that these nanocubes might be useful in the development of optical devices.

Synthesis and characterization of nano- and microcrystalline cubes of pure and Ag-doped LiF

International Nuclear Information System (INIS)

Alharbi, Najlaa D; Salah, Numan; Habib, Sami S; Alarfaj, Esam

2013-01-01

Lithium fluoride (LiF) produced in single crystals and doped with proper activators is a highly sensitive phosphor used in several applications such as integrated optics, colour centre laser and radiation dosimetry. In this work, we have developed a new synthetic chemical co-precipitation route for the synthesis of well-crystallized micro- and nanocrystalline cubes of pure and silver (Ag)-doped LiF. The as-synthesized samples were characterized by x-ray diffraction (XRD), scanning electron microscopy, absorption spectrum, photoluminescence (PL) and Raman spectroscopy. Size of the produced cubes could be controlled in the range 10 µm-50 nm by varying the solvent:co-solvent ratio. Micro-sized cubes could be grown in the presence of water as a solvent, while ethanol, which acts as a co-solvent, is found to be effective in reducing the size to the nanoscale. XRD results show complete crystalline structures in a griceite phase. The PL result of pure nanocubes exhibits a broad band in the range 370-550 nm, while that doped with Ag shows a prominent band at 420 nm. Raman spectra of the pure and Ag-doped LiF samples display several bands located in the range 80-236 cm -1 . These results show that pure nanocubes of LiF have active colour centres without irradiation, which could be enhanced/modified by Ag dopants. This implies that these nanocubes might be useful in the development of optical devices.

Fitting Diffusion Item Response Theory Models for Responses and Response Times Using the R Package diffIRT

Directory of Open Access Journals (Sweden)

Dylan Molenaar

2015-08-01

Full Text Available In the psychometric literature, item response theory models have been proposed that explicitly take the decision process underlying the responses of subjects to psychometric test items into account. Application of these models is however hampered by the absence of general and flexible software to fit these models. In this paper, we present diffIRT, an R package that can be used to fit item response theory models that are based on a diffusion process. We discuss parameter estimation and model fit assessment, show the viability of the package in a simulation study, and illustrate the use of the package with two datasets pertaining to extraversion and mental rotation. In addition, we illustrate how the package can be used to fit the traditional diffusion model (as it has been originally developed in experimental psychology to data.

Induced pluripotent stem cell-derived limbal epithelial cells (LiPSC) as a cellular alternative for in vitro ocular toxicity testing.

Science.gov (United States)

Aberdam, Edith; Petit, Isabelle; Sangari, Linda; Aberdam, Daniel

2017-01-01

Induced pluripotent stem cells hold great potential to produce unlimited amount of differentiated cells as cellular source for regenerative medicine but also for in vitro drug screening and cytotoxicity tests. Ocular toxicity testing is mandatory to evaluate the risks of drugs and cosmetic products before their application to human patients by preventing eye irritation or insult. Since the global ban to use animals, many human-derived alternatives have been proposed, from ex-vivo enucleated postmortem cornea, primary corneal cell culture and immortalized corneal epithelial cell lines. All of them share limitations for their routine use. Using an improved protocol, we derived limbal epithelial cells from human induced pluripotent stem cells, named LiPSC, that are able to be passaged and differentiate further into corneal epithelial cells. Comparative RT-qPCR, immunofluorescence staining, flow cytometry analysis and zymography assays demonstrate that LiPSC are morphologically and molecularly similar to the adult stem cells. Moreover, contrary to HCE, LiPSC and primary limbal cells display similarly sensitive to cytotoxicity treatment among passages. Our data strongly suggest that LiPSC could become a powerful alternative cellular model for cosmetic and drug tests.

Induced pluripotent stem cell-derived limbal epithelial cells (LiPSC as a cellular alternative for in vitro ocular toxicity testing.

Directory of Open Access Journals (Sweden)

Edith Aberdam

Full Text Available Induced pluripotent stem cells hold great potential to produce unlimited amount of differentiated cells as cellular source for regenerative medicine but also for in vitro drug screening and cytotoxicity tests. Ocular toxicity testing is mandatory to evaluate the risks of drugs and cosmetic products before their application to human patients by preventing eye irritation or insult. Since the global ban to use animals, many human-derived alternatives have been proposed, from ex-vivo enucleated postmortem cornea, primary corneal cell culture and immortalized corneal epithelial cell lines. All of them share limitations for their routine use. Using an improved protocol, we derived limbal epithelial cells from human induced pluripotent stem cells, named LiPSC, that are able to be passaged and differentiate further into corneal epithelial cells. Comparative RT-qPCR, immunofluorescence staining, flow cytometry analysis and zymography assays demonstrate that LiPSC are morphologically and molecularly similar to the adult stem cells. Moreover, contrary to HCE, LiPSC and primary limbal cells display similarly sensitive to cytotoxicity treatment among passages. Our data strongly suggest that LiPSC could become a powerful alternative cellular model for cosmetic and drug tests.

Neutron flux measurement with 6Li and 7Li dual glass scintillators by γ compensation method

International Nuclear Information System (INIS)

Ji Changsong; Zhang Shulan; Zhang Shuheng

1996-01-01

Based on the characteristics of 6 Li glass scintillator which is sensitive to both neutron and gamma rays, and 7 Li glass scintillator which is sensitive to gamma rays only, a new method of detecting weak neutron flux under interference of strong gamma radiation has been investigated by means of 6 Li- 7 Li pair glass scintillator gamma compensation method. The result of neutron flux measurement by above-mentioned method with an error of about 1% when the gamma ray interference is up to 18.7% has been obtained

Neutron flux measurement with 6Li and 7Li dual glass scintillators by γ compensation method

International Nuclear Information System (INIS)

Ji Changsong; Zhang Shulan; Zhang Shuheng

1998-01-01

Based on the characteristics of 6 Li glass scintillator which is sensitive to both neutron and gamma rays, and 7 Li glass scintillator which is sensitive to gamma rays only, a new method of detecting weak neutron flux under interference of strong gamma radiation has been investigated by mans of 6 Li- 7 Li dual glass scintillator gamma compensation method. The result of neutron flux measurement by above-mentioned method with an error of about 1% when the gamma ray interference is up to 18.7% has been obtained

Magnetic properties of lithium rare-earth fluorides: Ferromagnetism in LiErF4 and LiHoF4 and crystal-field parameters at the rare-earth and Li sites

DEFF Research Database (Denmark)

Hansen, P. E.; Johansson, Torben; Nevald, Rolf

1975-01-01

Single crystals of LiErF4 and LiHoF4 have been grown and their magnetic properties measured from 1.3 K to 300 K. LiHoF4 turned out to be a nearly ideal Ising ferromagnet with TC=1.30±0.05 K and a saturation magnetization along the crystalline c axis of (6.98±0.02)μB. In LiErF4 no ordering...... was observed, but extrapolation indicates that below 0.5 K it will be ferromagnetic with the magnetic moments in the crytalline ab plane. From the susceptibilities the crystal-field parameters Bnm with (n, m)=(2, 0), (4, 0), (4, 4), (6, 0), (6, 4) have been extracted giving for Er3+ in LiErF4: 430., -985......., 1185., -5., 740.+i135. (cm-1) and for Ho3+ in LiHoF4: 470., -825., 1050., -10., 760.+i150 (cm-1). The exchange constants were found to be small compared to the dipole interactions. Furthermore the 7Li NMR spectra have been obtained in these materials as well as in LiTbF4 thereby determining the second...