Academic literature on the topic 'TCR particles'
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Journal articles on the topic "TCR particles"
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Poornaiah, B., G. Srinivasa Rao, A. V. Prathap Kumar, and Y. Srinivasa Rao. "Low Frequency Noise and TCR Mechanisms in Polymer Thick Film Resistors." Journal of Microelectronics and Electronic Packaging 7, no. 2 (April 1, 2010): 105–10. http://dx.doi.org/10.4071/1551-4897-7.2.105.
Full textAbstract:
The paper aims to propose a more realistic low frequency noise and TCR mechanisms in polymer thick film resistors. The variation of low frequency noise (also called current noise) and TCR of polymer thick film resistor, namely, PVC-graphite thick film resistor, with parameters such as high volume fraction and grain size has been studied. A model is proposed to explain the observed variations, which assumes that the texture of the polymer thick film resistor consists of densely packed conducting particles with a cavity at the center of the structure. Further, the effect of the cavity diameter of polymer thick film resistor on current noise and TCR is explained using the same model. The current noise of these resistors is controlled mainly by the average relative resistance fluctuations between the conducting particles and the number of contacts each particle has with its neighbors. The TCR of these resistors is controlled mainly by the expansion properties of the insulating medium. The variation of TCR with high voltage is also due to the change in number of contacts and the contact area between the conducting particles.
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Lo, Ying-Chun, Michael Edidin, and Jonathan Powell. "Selective activation of antigen-specific T cells by nano-particles (144.22)." Journal of Immunology 184, no. 1_Supplement (April 1, 2010): 144.22. http://dx.doi.org/10.4049/jimmunol.184.supp.144.22.
Full textAbstract:
Abstract We hypothesized that the spatial differences of surface TCR between naïve and previously activated cells might be exploited to enable anti-CD3 coated quantum dot (Invitrogen, Qdots) to selectively activate antigen specific cells. CD4+ Rag -/- TCR transgenic T cells specific for Pigeon Cytochrome c were stimulated +/- peptide with or without anti-CD3 Qdots and evaluated for proliferation. Anti-CD3 Qdots markedly enhanced proliferation of T cells previously incubated with low dose peptide, but did not drive proliferation of T cells that were incubated in medium alone, though these cultured T cells responded to soluble anti-CD3. We repeated this experiment using CD4+ 6.5 TCR transgenic T cells, specific for hemagglutinin (HA). These mice are Rag+/+ allowing us to simultaneously evaluate the ability of anti-CD3 Qdots to activate both the 6.5+ and 6.5- T cells. Soluble anti-CD3 resulted in proliferation even in the absence of peptide. When cells were first incubated with low dose HA peptide as expected only the 6.5+ T cells proliferated. Addition of anti-CD3 Qdots to such cultures led to a marked enhancement of proliferation of the 6.5+ T cells but not of the 6.5- T cells in a single culture. In similar experiments using CD8+ TCR transgenic T cells specific for HA, once again, only the HA specific CD8+ T cells responded to the anti-CD3 Qdots. Experiments to exploit these findings in vivo in models of infection and tumor immunity are underway.
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Shiba, Kota, and Makoto Ogawa. "Precise Synthesis of Well-Defined Inorganic-Organic Hybrid Particles." Chemical Record 18, no. 7-8 (January 10, 2018): 950–68. http://dx.doi.org/10.1002/tcr.201700077.
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Cao, Zi-Quan, and Guo-Jie Wang. "Multi-Stimuli-Responsive Polymer Materials: Particles, Films, and Bulk Gels." Chemical Record 16, no. 3 (May 6, 2016): 1398–435. http://dx.doi.org/10.1002/tcr.201500281.
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Mescher, M. F. "Surface contact requirements for activation of cytotoxic T lymphocytes." Journal of Immunology 149, no. 7 (October 1, 1992): 2402–5. http://dx.doi.org/10.4049/jimmunol.149.7.2402.
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Abstract Cell activation resulting from binding of receptors on one cell to ligands on another is governed by receptor affinities and by ligand concentrations. Effective ligand concentration is determined by its density on the cell surface, but receptor occupancy level will also be influenced by the area of surface contact between the cells. The present study demonstrates the critical importance of a large, continuous surface contact area for effective CTL activation. Using class I alloantigen immobilized on latex microspheres, particle sizes of 4 to 5 microns were found to provide an optimum stimulus. Below 4 microns, responses decreased rapidly with decreasing particle size, and large numbers of small particles could not compensate for suboptimal size. Comparable size dependence was found for activation of degranulation by cloned CTL and for stimulation of in vitro generation of CTL responses by spleen cells from in vivo primed mice. In the presence of fluid-phase anti-TCR antibody, CD8-dependent binding to non-Ag class I (i.e., class I that is not recognized by the TCR) can provide a costimulatory signal to activate degranulation. This response is also critically dependent upon the class I being presented on a particle of 4 or 5 microns diameter. The results suggest that sufficient receptor occupancy (both TCR and CD8) over a contiguous region of the cell surface, as opposed to total interactions over the entire cell surface, is a critical determinant for activation. The ability of CTL to distinguish between Ag on cell-size vs subcellular fragments is probably necessary for their effective functioning, and may also explain the inability to significantly influence CTL activation in vivo with subcellular or soluble forms of Ag.
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Choudhuri, Kaushik, Jaime Llodra, Jones Tsai, Eric Roth, Susana Gordo, Kai Wucherpfennig, Lance Kam, David Stokes, and Michael Dustin. "Polarized release and retroviral subversion of TCR-enriched microvesicles at the T cell immunological synapse (P6155)." Journal of Immunology 190, no. 1_Supplement (May 1, 2013): 118.1. http://dx.doi.org/10.4049/jimmunol.190.supp.118.1.
Full textAbstract:
Abstract The recognition events that mediate adaptive cellular immunity depend on intercellular contacts between T cells and antigen presenting cells (APC). T cell signaling is initiated at these specialized junctions between T cells and APCs, known as the immunological synapse (IS), when surface-expressed antigen receptors (TCR) recognize peptide fragments of pathogens (pMHC) on APCs. Using high resolution optical and electron microscopy, optical-EM correlation, and electron-tomography, we show that centrally accumulated TCR at the IS is located on the surface of extracellular microvesicles that bud at the IS center and are recognized by APC bearing cognate antigen. An early endosomal-sorting complex required for transport (ESCRT) sorts TCR for inclusion in microvesicles, while terminal ESCRT components mediate scission of microvesicles from the T cell plasma membrane. The HIV polyprotein GAG co-opts this process by displacing TCR from microvesicles, resulting in release of virus-like particles at the antigen-dependent IS. We conclude that post-signaling TCR accumulates at the IS center and is released in extracellular microvesicles by an ESCRT-dependent mechanism triggered by T cell activation. These microvesicles mediate intercellular communication in immune cell collaboration, and can be co-opted by HIV GAG for viral transmission across antigen-dependent synapses.
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Choudhuri, Kaushik, Jaime Llodra, Lance Kam, David Stokes, and Micheal Dustin. "Antigen-induced release and retroviral subversion of TCR-enriched microvesicles at the CD4+ T cell immunological synapse (58.5)." Journal of Immunology 188, no. 1_Supplement (May 1, 2012): 58.5. http://dx.doi.org/10.4049/jimmunol.188.supp.58.5.
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Abstract The immunological synapse (IS) is a specialized junction that forms between T cells and antigen presenting cells, which is critical for effective T cell antigen recognition and effector functions. Its spatiotemporal evolution results in laterally segregated supramolecular domains composed of a peripheral adhesive ring of the β2 integrin LFA-1 and its ligand ICAM-1, and centrally accumulated T cell receptors (TCR). The molecular and cell biological basis for supramolecular domain organization at the IS remains unclear. Here we show, using novel correlative optical-electron microscopy methods in conjunction with electron tomography, that centrally accumulated TCR is located on the surface of microvesicles that are shed at the IS center. The ESCRT I member TSG101 sorts TCR into microvesicles. TCR-enriched microvesicles (TEMs) are transferred from T cell to B cell during cognate antigen recognition, and B cells initiate intracellular signals in response to TEMs, suggesting their involvement in intercellular communication between immune cells. Expression of the HIV GAG structural polyprotein in human CD4+ T cells, displaces TCR from microvesicles at the IS, resulting in the release of GAG-containing virus-like particles. These findings provide an ultrastructural basis for supramolecular domain organization at the IS, and identify an ESCRT-dependent mechanism for production of stimulatory TEMs, which may be co-opted during infection for the release of enveloped viruses.
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Yan, Zong-Yao, Jian-Yong Liu, and Jia-Rong Niu. "Research of a Novel Ag Temperature Sensor Based on Fabric Substrate Fabricated by Magnetron Sputtering." Materials 14, no. 20 (October 12, 2021): 6014. http://dx.doi.org/10.3390/ma14206014.
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TPU-coated polyester fabric was used as the substrate of a flexible temperature sensor and Ag nanoparticles were deposited on its surface as the temperature sensing layer by the magnetron sputtering method. The effects of sputtering powers and heat treatment on properties of the sensing layers, such as the temperature coefficient of resistance (TCR), linearity, hysteresis, drift, reliability, and bending resistance, were mainly studied. The results showed that the TCR (0.00234 °C−1) was the highest when sputtering power was 90 W and sputtering pressure was 0.8 Pa. The crystallinity of Ag particles would improve, as the TCR was improved to 0.00262 °C−1 under heat treatment condition at 160°. The Ag layer obtained excellent linearity, lower hysteresis and drift value, as well as good reliability and bending resistance when the sputtering power was 90 W. The flexible temperature sensor based on the coated polyester fabric improved the softness and comfortableness of sensor, which can be further applied in intelligent wearable products.
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Cheng, Ching-Tai, Jiang-Tsair Lin, and Hong-Ching Lin. "Addition of Nb2O5 on the electrical properties of buried resistors in low-temperature cofired ceramics." Journal of Materials Research 18, no. 5 (May 2003): 1211–18. http://dx.doi.org/10.1557/jmr.2003.0166.
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Nb2O5 was added to buried resistors for low-temperature cofired ceramics, and the electrical properties of the resultant resistors were examined. Remarkable increases in electrical resistivity and attractive decreases in the temperature coefficient of resistance (TCR) were observed by the addition of Nb2O5, which was attributed to the high solubility of Nb2O5 into the PbO-SiO2-Al2O3 matrix glass. With higher dissolved contents of Nb2O5 into the glass, the resistivity of buried resistors increased by approximately six-fold magnitude, while TCR decreased substantially toward zero. It was indicated that the conductance for these buried resistors was limited by tunneling of charge carriers through the thin glass layer penetrating into the ruthenium-oxide agglomerates. A larger separation observed between RuO2 particles due to high solubility of Nb2O5 in the glass increased the charging energy (E) and lump term (Rbo), which in turn gave rise to a higher resistivity and a lower TCR value.
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Kolmakov, Andrei, and D. W. Goodman. "In situ scanning tunneling microscopy of oxide-supported metal clusters: Nucleation, growth, and thermal evolution of individual particles." Chemical Record 2, no. 6 (November 2002): 446–57. http://dx.doi.org/10.1002/tcr.10045.
Full textDissertations / Theses on the topic "TCR particles"
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Maslov, Mikhail. "Particle transport in JET and TCV H-mode plasmas /." Lausanne : EPFL, 2009. http://library.epfl.ch/theses/?nr=4450.
Full textAbstract:
Thèse Ecole polytechnique fédérale de Lausanne EPFL, no 4450 (2009), Faculté des sciences de base SB, Programme doctoral Physique, Centre de recherches en physique des plasmas CRPP (CRPP Association Euratom CRPP-AE). Dir.: Henri Weisen.
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Silva, Ruy Pepe da. "Transporte de partículas e energia no plasma do tokamak TBR-1: diagnósticos e estudo experimental." Universidade de São Paulo, 1989. http://www.teses.usp.br/teses/disponiveis/43/43131/tde-16122013-153129/.
Full textAbstract:
Os estudos sobre o plasma na região da borda de máquinas tokamak têm se intensificado nos últimos anos em decorrência da constatação de que o comportamento do plasma na região central da máquina é bastante influenciado por processos que ocorrem na borda da coluna. Neste trabalho feito um estudo experimental das propriedades de transporte do plasma na região da sombra do limitador do TBR-l, um tokamak de pequeno porte em operação no Instituto de Física da Universidade de São Paulo. São também determinados os tempos de confinamento globais de partículas e energia. Três foram os diagnósticos usados neste trabalho. Inicialmente, é abordada a utilização de sondas de Langmuir para a obtenção de perfis radiais e temporais da temperatura de elétrons, densidade e potencial de plasma; descreve-se também o arranjo experimental usado para este diagnóstico. A seguir, discute-se o projeto e a construção de uma sonda sensível a íons associada a um sistema eletrônico que permitiu a determinação simultânea das temperaturas locais de íons e elétrons. Finalmente, é discutido o dimensionamento e a implantação de um interferômetro de microondas para medidas de densidade de elétrons na região central da coluna de plasma do TBR-1; o sistema opera em 65 GHz e toda a eletrônica associada foi projetada e construída em nosso Laboratório. Os resultados obtidos com as sondas foram analisados com o ajuda de um modelo não colisional de transporte de partículas e energia para a região da sombra do limitador de máquinas tokamak. A partir dos decaimentos radiais da termperatura de elétrons (\'lâmbda IND. e\' \'APROXIMADAMENTE IGUAL A\' 2,6cm) e da densidade (\'lâmbda IND. n\' \'APROXIMADAMENTE IGUAL A\' 1,4cm), bem como do fator de transmissão de energia para os elétrons (\'delta IND. e\' \'APROXIMADAMENTE IGUAL A\' 4), determinou-se o coeficiente de difusão perpendicular ao campo magnético (\'D IND. 1\' \'APROXIMADAMENTE IGUAL A\' 6 \'m POT. 2\'\'s POT. -1\') e a difusividade térmica dos elétrons (\'qui POT. e IND. 1\' \'APROXIMADAMENTE IGUAL A\' 8 \'m POT. 2\'\'s POT. -1\'), resultados que indicam valores próximos aos previstos pelo modelo de Bohm. As medidas das temperaturas de íons e elétrons mostram um claro desacoplamento térmico entre íons e elétrons (\'T IND. i\'/\'T IND. e\' \'APROXIMADAMENTE IGUAL A\' 2). As medidas de densidade obtidas no centro da coluna, em conjunto com as obtidas na borda, permitiram a determinação dos tempos de confinamento globais de partículas (\'tau IND. p\'\'APROXIMADAMENTE IGUAL A\' 1,8 x \'10 POT. -3\'s) e de energia (\'tau IND. E\'\'APROXIMADAMENTE IGUAL A\' 1,2 x \'10 POT. -4\'s). Os resultados foram comparados com os previstos por várias leis de escala.The study of the plasma edge in Tokamak machines has increased in recent last years, since the recognition that the behavior of the plasma core is influenced by the Physical processes that occur in the edge region. This work develops an experimental stud) of plasma transport properties in the shadow region of TBR-l limiter. TBR-l is a small Tokamak in operation in the Physics Institute of São Paulo University. We have also determined the global confinement time of particles and energy. We have used three diagnostics: a Langmuir probe, an ion sensitive probe, and a microwave interferometer. Initially we discuss the use of Langmuir probes in Tokamak machines to obtain temporal and radial profiles of electron temperature, plasma density and potential; we show also the experimental arrangement used in the TBR-l for this diagnostic. Then, we discuss the design and construction of an ion sensitive probe associated with an electronic system, that was used to obtain, simultaneously, local ion and electron temperature. Finally we discuss a microwave interferometry system that has been built for the TBR-1. The microwave generator is a reflex Klystron (f = 65 GHz), and with the interferometer we obtained electron density time profiles of the center of TBR-l plasma column. All the electronics associated with the interferometer were designed and built in our laboratory. The results obtained with the probes are discussed with the help of a collisionless model for Tokamak scrape-off plasma. With the radial e-foldings of electron temperature (e 2.6 cm) and density (n 1.4 cm), and the sheath electron transmission coefficient (e 4) we have determined the cross-field diffusion coefficient (D1 6 m2s-1) and the electron cross-field thermal diffusivity (e1 8 m2s-1). These results indicate values near those predicted by the Bohm model. The measurements of electron and ion temperature shows a clear thermal decoupling between ions and electrons (T1/Te 2). The measurements of plasma parameters in the center of the plasma column, with that obtained with the probes permitted the determination of the particle (p 1.8 x 10-3s) and energy (e 1.2 x10-4s) global confinement times. These results were compared with those predicted by scaling laws.
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Hattingh, Barend Burgert. "Product evaluation and reaction modelling for the devolatilization of large coal particles / Barend Burgert Hattingh." Thesis, North-West University, 2012. http://hdl.handle.net/10394/8739.
Full textAbstract:
A fundamental understanding of the process of devolatilization requires extensive knowledge of
not only the intrinsic properties of the parent coal and its subsequent formed products (tars,
gases and chars), but also its characteristic reaction rate behaviour. Devolatilization behaviour
has been extensively addressed in literature with the use of powdered coal samples, which
normally do not adhere to particle size constraints of coal conversion processes utilizing lump
coal. The aim of this investigation was therefore to assess the devolatilization behaviour (with
respect to product yield and -quality; and reaction rate modelling) of four typical South African
coals (UMZ, INY, G#5 and TSH) confined to the large particle regime. All four coals were found
to be bituminous in rank, with vitrinite contents ranging between 24.4 vol.% and 69.2 vol.%
(mineral matter free basis). Two were inertinite-rich coals (UMZ and INY) and the other two
were vitrinite-rich coals (G#5 and TSH). From thermoplasticity measurements it was evident that
only coal TSH displayed extensive thermoplastic behaviour, while a comparison between
molecular properties confirmed the higher abundance of poly-condensed aromatic structures
(aromaticity of 81%) present in this coal.
Product evolution was evaluated under atmospheric conditions in a self-constructed, large
particle, fixed-bed reactor, on two particle sizes (5 mm and 20 mm) at two isothermal reactor
temperatures (450°C and 750°C) using a combination of both GC and MS techniques for gas
species measurement, while standard gravimetric methods were used to quantify tar- and char
yield respectively. Elucidation of tar- and char structural features involved the use of both
conventional- and advanced analytical techniques. From the results it could be concluded that
temperature was the dominating factor controlling product yield- and quality, with significant
increases in both volatile- and gas yield observed for an increase in temperature. Tar yields
ranged between 3.6 wt.% and 10.1 wt.% and increased in the order UMZ < INY < TSH < G#5,
with higher tar yields obtained for coal G#5, being ascribed to larger abundances of vitrinite and
liptinite present in this coal. For coal TSH, lower tar yields could mainly be attributed to the
higher aromaticity and extensive swelling nature of this coal. Evolved gases were found to be
mainly composed of H2, CH4, CO and CO2, low molecular weight olefins and paraffins; and
some C4 homologues. Advanced analytical techniques (NMR, SEC, GC-MS, XRD, etc.)
revealed the progressive increase of the aromatic nature of both tars and chars with increasing
temperature; as well as subsequent differences in tar composition between the different parent coals. In all cases, an increase in devolatilization temperature led to the evolution of larger
amounts of aromatic compounds such as alkyl-naphthalenes and PAHs, while significant
decreases in the amount of aliphatics and mixed compounds could be observed. From 13C
NMR, HRTEM and XRD carbon crystallite results it was clear that an increase in temperature
led to the formation of progressively larger, more aromatic and structurally orientated polycondensed
carbon structures.
Reaction rate studies involved the use of non-isothermal (5-40 K/min) and isothermal (350-
900°C) thermogravimetry of both powdered (-200 μm) and large particle samples (20 mm) in
order to assess intrinsic kinetics and large particle rate behaviour, respectively. Evaluation of
the intrinsic kinetic parameters of each coal involved the numerical regression of non-isothermal
rate data in MATLAB® 7.1.1 according to a pseudo-component modelling philosophy. Modelling
results indicated that the intrinsic devolatilization behaviour of each coal could be adequately
described by using a total number of eight pseudo-components, while reported activation
energies were found to range between 22.3 kJ/mol and 244.3 kJ/mol. Description of the rate of
large particle devolatilization involved the evaluation of a novel, comprehensive rate model
accounting for derived kinetics, heat and mass transport effects, as well as physical changes
due to particle swelling/shrinkage. Evaluation of the proposed model with the aid of the
COMSOL Multiphysics 4.3 simulation software provided a suitable fit to the experimental data of
all four coals, while simulation studies highlighted the relevant importance of not only the effect
of particle size, but also the importance of including terms affecting for heat losses due to
particle swelling/shrinkage, transport of volatile products through the porous char structure, heat
of reaction and heat of vaporization of water.Thesis (PhD (Chemical Engineering))--North-West University, Potchefstroom Campus, 2013
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Vallar, Matteo. "Neutral beam fast particle physics in fusion plasma integrated scenarios." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3425245.
Full textAbstract:
Neutral beam injection heating is one of the most reliable ways to heat a
plasma up to the temperatures needed to achieve steady-state thermonuclear
fusion. This system injects neutral particles with energy much higher than
the bulk ion energy, introducing a population of energetic particles which
collide with the plasma ions and electrons. In this way energy and momen-
tum are transferred to the plasma giving as final result an increase of the tar-
get plasma temperature and, depending on the beam characteristics, possible
modifications of its flow and current profile.
Numerical modelling of the behaviour of fast particles in tokamak plasma
is the subject of this thesis. Analytical and Monte Carlo models have been
applied to different devices (RFX-mod, JT-60 SA and TCV) in order to study
the impact of these particles in both inductive (standard) and non-inductive
(advanced) scenarios. Comparison between the different codes have been
made in order to assess if the different models apply correctly to the cases
studied.
RFX-mod device is under modification and the installation of a neutral
beam injector (with fixed parameters and geometry) is in the upgrade hy-
pothesis. The impact of energetic particles in RFX-mod tokamak plasmas is
discussed in this work using METIS fast tokamak simulator and compared
with NUBEAM Monte Carlo code.
The impact of energetic particles in JT-60 SA superconducting tokamak is
studied with ASCOT Monte Carlo orbit solver. This device relies on a wide
and flexible set of beams for plasma heating and current drive, both for stan-
dard and advanced scenarios. The behaviour of the fast particles in JT-60 SA
standard and advanced tokamak plasmas is analysed, showing the reliability
of the neutral beam system in this device.
Neutral beam injection heating in TCV is the last topic studied in this
thesis. The impact of electron cyclotron wave injection heating on energetic
particles behaviour has been studied in advanced tokamak scenarios, where
the expected performances are not achieved using the combination of the
two heating systems. Comparison between ASCOT and NUBEAM code is
performed in order to check which of the two codesO aquecimento por injeção de feixes de neutros é um dos métodos mais fiáveis para aquecer um plasma até às temperaturas necessárias para atingir fusão termonuclear estacionária. Este tipo de sistema injeta neutros com ener- gias muito superiores à energia dos iões que constituem o grosso do plasma, introduzindo uma população de partículas energéticas que, colidindo com os iões e electrões do plasma, transmite a energia ao plasma. Adicionalmente, esta população de partículas energéticas também induz corrente no plasma, contribuindo para a manutenção da descarga. O tema central desta tese incide na modelização numérica do compor- tamento de partículas rápidas num plasma de Tokamak. Códigos analíti- cos e de numéricos de Monte Carlo foram aplicados a diferentes máquinas (RFX-mod, JT-60 SA and TCV) com vista a estudar o impacto destas partícu- las em cenários de operação indutivos (cenário standard) e não indutivos (avançado). A máquina RFX-mod está a ser melhorada e a instalação de injectores de feixes neutros (com parâmetros e geometria fixos) é uma das possíveis melhorias. Deste modo, o impacto das partículas energéticas nos plasmas do RFX-mod é discutida neste trabalho usando o código analítico METIS. O impacto de partículas energéticas no tokamak superconductor JT-60SA é estudado com o código de Monte Carlo ASCOT. Neste Tokamak, o aqueci- mento do plasma e a geração de corrente, seja em cenário de operação stan- dard ou avançado, é garantido em grande parte por um conjunto de feixes de injeção de neutros. Neste trabalho, a dinâmica das partículas rápidas nos cenários standard e avançado do JT-60SA é analisada, evidenciando a fiabili- dade do sistema de injeção de neutros no Tokamak. Um injector de feixes neutros foi instalado no Tokamak TCV há três anos. Este feixe é importante dado que deposita potência predominantemente nos iões e permite alargar o regime de operação do tokamak. Nesta tese, após uma revisão da condição atual do feixe de neutros e da operação com ele realizada nos últimos três anos, é feito um estudo sobre o impacto do aque- cimento por injeção de ondas electro-c
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Šála, David. "Systém pro automatickou kalibraci robotického nástroje." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2020. http://www.nusl.cz/ntk/nusl-413190.
Full textAbstract:
This Master's thesis describes the design and implementation of an experimental sample for automatic calibration of a robotic tool using machine vision methods under the auspices of the company SANEZOO EUROPE s.r.o. It deals with the analysis of all used methods of performing TCP calibration, on the basis of which it is implemented. The application is based on the Point-counterpoint method, where the robot is guided against the calibration point from three different directions, all perpendicular to each other. The calibration point is set using the ArUco marker. In order to detect the endpoint are used images from two cameras that are at the right angles to each other. Using conventional computer vision methods and an HSV filter, the endpoint of the instrument is found in the images and is guided to the calibration point. From the obtained coordinates, the searched endpoint of the robotic tool in the robot coordinates is found using the optimization method Particle Swarm Optimization. This application, therefore, performs TCP calibration in a fast time, thus reducing production downtime almost without human intervention.
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Metheny, Maura A. "Evaluation of groundwater flow and contaminant transport at the Wells G&H Superfund Site, Woburn, Massachusetts, from 1960 to 1986 and estimation of TCE and PCE concentrations delivered to Woburn residences." The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1080248307.
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Hanumanth, Rao C. "Semiconductor Photocatalysts For The Detoxification Of Water Pollutants." Thesis, Indian Institute of Science, 2000. http://etd.iisc.ac.in/handle/2005/216.
Full textAbstract:
Water pollution is a major concern in vast countries such as India and other developing nations. Several methods of water purification have been practiced since many decades, Semiconductor photocatalysis is a promising technique, for photodegradation of various hazardous chemicals that are encountered in waste waters. The great significance of this technique is that, it can degrade (detoxify) various complex organic chemicals, which has not been addressed by several other methods of purification. This unique advantage made this field of research to attract many investigators particularly in latter eighties and after.
This thesis incorporates the studies on the various semiconductor photocatalysts that have been employed for the detoxification purposes. The fundamental principles involved in the photoelectrochemistry, reactions at the interface (solid - liquid or solid - gas) and photocatalytic reactions on fine particles are briefed. General nature and size quantization in semiconductor particles, photocatalytically active semiconductors, TiCh and ABO3 systems, chemical systems and modifications for solar energy conversions are brought out in the introduction chapter besides giving brief description about photocatalytic mineralization of water pollutants with mechanism involved, formation of reactive species and the factors influencing photomineralization reactions. Scope of the present work is given at the end of the first chapter.
Second chapter deals with the materials used for the preparation of photocatalyst, preparative techniques, methods of analysis, instruments employed for the photodegradation experiments and a brief description of material characterization methods such as X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, differential thermal analysis, optical absorption spectro photometry, Electron paramagnetic resonance (EPR), and gas chromatograph - mass spectroscopy (GC - MS). Various preparative routes such as wet chemical and hydrothermal methods for obtaining TiO2 (both rutile and anatase forms), BaTiOs and SrTiO3 fine particles and the chemical analysis of their constituents have been described in brief.
Third chapter presents the results of materials characterization. T1O2 (rutile and anatase), BaTiO3 and SrTiO3 have been characterized separately using various techniques. Different routes of obtaining the photocatalyst fine particles, heat treatment at various temperature ranges, experimental procedures and the results of characterization are brought out in this chapter.
Fourth and fifth chapters present the details of degradation studies carried out on the photomineralization of chlorophenol, trichloroethylene and formaldehyde. Studies include photodegradation of the pollutants with different catalysts varying experimental conditions to check the effects of change in
concentration of pollutants, oxidizer, pH, surface hydroxylation, etc. The most favorable conditions for the complete mineralization of the
pollutants have been studied. In case of TiO2, anatase form has shown greater photoactivity when compared to rutile and complete mineralization of chlorophenols has been achieved at low pollutant
concentrations, neutral pH, with H2O2 and UV illumination. Retarding effects of surface hydroxylation and the formation of peroxotitanium species during photodegradation have been presented. TCE and HCHO degradation with BaTiO3/SrTiO3 has been studied. Photocatalyst heat-treated at 1100°G-1300°C is found to be highly active in combination with H2O2 as electron scavenger. HCHO is not getting degraded to its completeness in aqueous conditions owing to the strong competition in surface adsorption posed by H2O molecules. Vapour-solid phase reaction however gave good results in the detoxification of HCHO via disproportionation. Summary and conclusions are given at the end of the thesis.
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Hanumanth, Rao C. "Semiconductor Photocatalysts For The Detoxification Of Water Pollutants." Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/216.
Full textAbstract:
Water pollution is a major concern in vast countries such as India and other developing nations. Several methods of water purification have been practiced since many decades, Semiconductor photocatalysis is a promising technique, for photodegradation of various hazardous chemicals that are encountered in waste waters. The great significance of this technique is that, it can degrade (detoxify) various complex organic chemicals, which has not been addressed by several other methods of purification. This unique advantage made this field of research to attract many investigators particularly in latter eighties and after.
This thesis incorporates the studies on the various semiconductor photocatalysts that have been employed for the detoxification purposes. The fundamental principles involved in the photoelectrochemistry, reactions at the interface (solid - liquid or solid - gas) and photocatalytic reactions on fine particles are briefed. General nature and size quantization in semiconductor particles, photocatalytically active semiconductors, TiCh and ABO3 systems, chemical systems and modifications for solar energy conversions are brought out in the introduction chapter besides giving brief description about photocatalytic mineralization of water pollutants with mechanism involved, formation of reactive species and the factors influencing photomineralization reactions. Scope of the present work is given at the end of the first chapter.
Second chapter deals with the materials used for the preparation of photocatalyst, preparative techniques, methods of analysis, instruments employed for the photodegradation experiments and a brief description of material characterization methods such as X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, differential thermal analysis, optical absorption spectro photometry, Electron paramagnetic resonance (EPR), and gas chromatograph - mass spectroscopy (GC - MS). Various preparative routes such as wet chemical and hydrothermal methods for obtaining TiO2 (both rutile and anatase forms), BaTiOs and SrTiO3 fine particles and the chemical analysis of their constituents have been described in brief.
Third chapter presents the results of materials characterization. T1O2 (rutile and anatase), BaTiO3 and SrTiO3 have been characterized separately using various techniques. Different routes of obtaining the photocatalyst fine particles, heat treatment at various temperature ranges, experimental procedures and the results of characterization are brought out in this chapter.
Fourth and fifth chapters present the details of degradation studies carried out on the photomineralization of chlorophenol, trichloroethylene and formaldehyde. Studies include photodegradation of the pollutants with different catalysts varying experimental conditions to check the effects of change in
concentration of pollutants, oxidizer, pH, surface hydroxylation, etc. The most favorable conditions for the complete mineralization of the
pollutants have been studied. In case of TiO2, anatase form has shown greater photoactivity when compared to rutile and complete mineralization of chlorophenols has been achieved at low pollutant
concentrations, neutral pH, with H2O2 and UV illumination. Retarding effects of surface hydroxylation and the formation of peroxotitanium species during photodegradation have been presented. TCE and HCHO degradation with BaTiO3/SrTiO3 has been studied. Photocatalyst heat-treated at 1100°G-1300°C is found to be highly active in combination with H2O2 as electron scavenger. HCHO is not getting degraded to its completeness in aqueous conditions owing to the strong competition in surface adsorption posed by H2O molecules. Vapour-solid phase reaction however gave good results in the detoxification of HCHO via disproportionation. Summary and conclusions are given at the end of the thesis.
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Evelyne, Rita J. "Evaluation of Btex Contamination in Bengaluru Groundwater and Remediation of Contaminated Water Samples." Thesis, 2020. https://etd.iisc.ac.in/handle/2005/4602.
Full textAbstract:
BTEX (benzene, toluene, ethylbenzene, and xylene isomers) are monoaromatic, volatile organic compounds (VOCs) with single benzene ring and various degree of alkylation. US EPA classifies benzene and TEX (toluene, ethylbenzene, and xylene) as Class A (Carcinogenic) and Class D pollutants, respectively. A major source of BTEX contamination in groundwater is leakage from storage tanks in gasoline filling stations and oil-refineries. Perusal of the groundwater quality data in problem areas of India shows availability of data for inorganic contaminants, microbial contaminants and pesticides but do not contain data on BTEX levels in groundwater.
Results of the study indicate that BTEX contamination of Bengaluru aquifers from leaky UST’s in petrol filling stations is not extensive as only 6 % of groundwater samples showed benzene presence in excess of the permissible limit, while TEX compounds were below permissible limit in all the 124 groundwater samples. BTEX levels in contaminated groundwater were sensitive to seasonal variations as higher BTEX concentrations were generally observed during post-monsoon than pre-monsoon season. Lower BTEX concentration during pre-monsoon is attributed to reduced leaching of organic compounds from the overlying soil overburden to aquifers.
A contaminant transport model using MODFLOW is created to obtain insight into the role of hydrodynamic dispersion and diffusion in the spread of BTEX plume in Bengaluru aquifer. Variations in Ss(specific storage) or Sy(specific yield) at given kx(aquifer permeability) did not affect the predicted BTEX concentrations in the observation well at any migration period. However, reduction in kx affected the BTEX concentration in the observation well. BTEX
migration modeled using the low kx (5E-7 m/s) generally agree well with the measured benzene, toluene, and total xylenes concentration values in the observation well.
Among various methods to treat BTEX contaminated water, adsorption has attracted considerable attention of researchers. Recycled materials such as tyre crumb rubber (TCR) have an advantage over other adsorbents, in terms of low cost and large availability. Permeable reactive barriers (PRB) are used for in-situ treatment of contaminated groundwater. The use of TCR particles as reactive media in PRB’s to treat BTEX contaminated groundwater is an attractive option, that has not been previously explored.
Results of the study showed that TCR particles are mainly composed by SBP (52.7%) and CB (24.5%) constituents. Despite a lesser presence (24.5%), the CB component of TCR accounts for bulk (83%) of toluene adsorption by the TCR-sand mix. Analysis of adsorption data using distribution coefficients (Kc), Scatchard plot and Freundlich isotherm implied that toluene molecules are adsorbed at energetically heterogeneous sites of the TCR particles. Adsorption in pores of different sizes was responsible for the heterogeneity of adsorption sites. Interactions between toluene molecules and the adsorption sites of TCR particles involve weak van der Waals attraction forces. Despite the weak bonding, bulk (91%) of the adsorbed toluene molecules is not released upon water leaching as the spatial arrangement of toluene molecules in the medium and fine pores of TCR particles hinders desorption. Adsorption isotherms identified 2.5% TCR + 97.5% sand mix as the optimum mix to treat toluene contaminated water. Batch experiment results predict that unit PRB column constructed with 2.5% TCR-97.5% sand mix can remediate 11013 KL of toluene contaminated (0.15 mg/L) groundwater near instantaneously.
Besides adsorption, biodegradation is extensively used to treat BTEX contaminated groundwater, wastewater, and subsurface soils. Microbial consortia isolated from activated sludge, gasoline contaminated soils, sea-tidal flat were successful in biodegradation of BTEX compounds. The feasibility of exploring bacterial cultures cultivated from gasoline contaminated soils and groundwater in Bengaluru city is an interesting bioremediation option.
Bioremediation is accomplished by enrichment of bacterial culture in minimal media with toluene as carbon source. Results of the study showed that Pseudomonas sp isolated from petroleum contaminated soil and Bacillus haynesii isolated from BTEX contaminated groundwater are capable of toluene biodegradation. At toluene concentrations of 5-300 mg/L, Pseudomonas could degrade 40 to 100% of the hydrocarbon concentration. Comparatively, Bacillus haynesii could degrade 22 to 66 % of available toluene concentration. Toluene degradation by the microbes followed first order kinetics with first order rate constant of 0.127 h-1. The lower toluene degradation ability of Bacillus haynesii is attributed to greater substrate inhibitory effect. Review of microbial facilitated toluene degradation studies indicate that Pseudomonas species have higher degradation efficiency than other bacteria strains.
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"A new approach to the environmental remediation of trichloroethylene (TCE) using functional iron/silica aerosol particles." Tulane University, 2007.
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The objective of this dissertation is to remediate groundwater contaminants such as trichloroethylene (TCE) by functional particles. The porous silica particles with zero valent iron were synthesized by an aerosol-assisted process and subsequent gas or liquid phase reduction. The surface properties of these particles were carefully controlled through silanol modification to realize the suitable particle affinity with target contaminants While aerosol silica particles incorporating nanoscale zero valent iron are reactive for groundwater TCE remediation, environmentally benign silica particles serve as effective carriers for nanoiron transport through soil. The presence of surface silanol groups on silica particles makes possible the surface property control via silanol modification using organic functional groups. This leads to preferred partition of particles on TCE/water interface. Additionally, aerosol silica particles with functional groups such as ethyl tails on the surface preferentially adsorb hydrophobic TCE during environmental remediation. This increases the local concentration of TCE in the vicinity of iron, thus promoting TCE degradation by iron The morphology of silica particles with iron can be controlled through introducing cetyltrimethyl ammonium bromide (CTAB) as the template. Solid silica particles with disordered mesostructure can be obtained at low CTAB concentration. A novel translation from solid particles to hollow spheres was observed at increased CTAB concentration. Low solubility of ferric chloride in ethanol has been found to be the key for such transition and a reasonable formation mechanism of hollow spheres will be proposed. Further thermal reduction of encapsulated ferric ions produces zero valent iron nanoparticles inside silica hollow spheres. The reactivity and partition characteristics of hollow particles with iron will also be discussedacase@tulane.edu
Books on the topic "TCR particles"
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TCP 2006. Springer, 2012.
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Tcp 2010. Springer, 2011.
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Tcp 2006 Proceedings Of The 4th International Conference On Trapped Charged Particles And Fundamental Physics Tcp 2006 Held In Parksville Canada 38 September 2006. Springer, 2007.
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Dilling, J., G. Gwinner, J. Thomson, and M. Comyn. Tcp 2006: Proceedings of the 4th International Conference on Trapped Charged Particles and Fundamental Physics Held in Parksville, Canada, 3-8 September 2006. Springer London, Limited, 2007.
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Jokinen, Ari, Juha Äystö, Tommi Eronen, and Anu Kankainen. Tcp 2010: Proceedings of the 5th International Conference on Trapped Charged Particles and Fundamental Physics Held in Tunturihotelli in Saariselkä, Finland, April 12-16 2010. Springer Netherlands, 2014.
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Wada, Michiharu, Peter Schury, and Yuichi Ichikawa. Tcp 2014: Proceedings of the 6th International Conference on Trapped Charged Particles and Fundamental Physics, Held in Takamatsu, Japan, 1-5, December 2014. Springer International Publishing AG, 2018.
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Wada, Michiharu, Peter Schury, and Yuichi Ichikawa. TCP 2014: Proceedings of the 6th International Conference on Trapped Charged Particles and Fundamental Physics, held in Takamatsu, Japan, 1-5, December 2014. Springer, 2017.
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Pollock, Rob. Total hip replacement: modes of failure. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199550647.003.007010.
Full textAbstract:
♦ Total hip replacements (THRs) may fail in various ways. They may become infected, they may be subject to aseptic loosening, they may dislocate, or a periprosthetic fracture may occur. The patient with a failed THR must be thoroughly assessed before treatment is contemplated♦ Infection may be acute or chronic. Assessment involves clinical assessment, plain radiographs, blood tests (C-reactive protein and erythrocyte sedimentation rate), hip aspiration, and, sometimes, nuclear medicine. The acutely infected hip may be treated with one-stage revision. This involves thorough lavage, debridement, and exchange of all modular components as well as long-term antibiotic therapy. The gold standard of treatment for a chronically infected THR is a two-stage revision. Success rates of 80–90% can be expected♦ Aseptic loosening typically occurs at the cement bone interface in hips where a metal-on-polyethylene bearing couple has been used. Bone resorption takes place as a result of an inflammatory response to small wear particles. After infection has been excluded the treatment of choice is a single-stage revision♦ Dislocation may be the result of patient factors, implant factors, or poor surgical technique. It is imperative for the clinician to minimize the risk by selecting patients carefully, using the correct combination of implants and performing surgery accurately♦ The management of periprosthetic fractures depends on how well the implants are fixed and quality of bone stock. Treatment ranges from simple fixation of the fracture through to revision augmented with strut allograft.
Book chapters on the topic "TCR particles"
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Canali, C., C. Carraro, L. Di Noto, D. Krasnicky, V. Lagomarsino, G. Testera, and S. Zavatarelli. "Particle manipulation techniques in AEgIS." In TCP 2010, 49–57. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-2588-1_6.
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Duan, Lunbo, and Lin Li. "Oxygen Carrier Aided Gasification (OCAG)." In Oxygen-Carrier-Aided Combustion Technology for Solid-Fuel Conversion in Fluidized Bed, 79–96. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-9127-1_5.
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AbstractGasification is regarded as an effective clean utilization technology of solid fuel, which can convert the chemical energy of solid fuel into gaseous fuel. However, the primary gas products contain not only the essential gas products, but also an unacceptable amount of tars, which will cause operational problems such as blockage of downstream equipment during gasification. Catalysts are often used after the gasifier to catalyze tar in the pyrolysis product gas. However, the activity ofcatalysts generally declines over time, as they will be poisoned by prolonged exposure to an atmosphere containing elements such as sulfur, chlorine and alkali metals. In addition, under the condition of high tar content, carbon deposition may form on the surface of catalyst, which leads to the deactivation of catalyst. The oxygen carrier particles of natural ores not only can transport oxygen, but also contain various metal elements that can be used as catalysts for tar cracking. Introduce the OCs to replace inert bed materials may not only provide a cheap catalyst for the technology, but also complete the transfer of oxygen between the two reactors, this process is oxygen carrier aided gasification (OCAG).
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Kelbon, Marcia, Scott Bousman, and Barbara Krieger-Brockett. "Conditions That Favor Tar Production from Pyrolysis of Large, Moist Wood Particles." In ACS Symposium Series, 41–54. Washington, DC: American Chemical Society, 1988. http://dx.doi.org/10.1021/bk-1988-0376.ch005.
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Phenrat, Tanapon, Daniel Schoenfelder, Mark Losi, June Yi, Steven A. Peck, and Gregory V. Lowry. "Treatability Study for a TCE Contaminated Area using Nanoscale- and Microscale-Zerovalent Iron Particles: Reactivity and Reactive Life Time." In ACS Symposium Series, 183–202. Washington DC: American Chemical Society, 2009. http://dx.doi.org/10.1021/bk-2009-1027.ch010.
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Sánchez, Caio G., Renata Andrade Figueiredo, Flávio Augusto Bueno Figueiredo, Elisabete Maria Saraiva Sánchez, Jesús Arauzo, Alberto Gonzalo Callejo, and Rolando Zanzi Vigouroux. "Liquid Products Characterization from Pyrolysis and Gasification." In Innovative Solutions in Fluid-Particle Systems and Renewable Energy Management, 167–98. IGI Global, 2015. http://dx.doi.org/10.4018/978-1-4666-8711-0.ch006.
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In this chapter there is described a tentative of obtain and characterize pyrolysis liquids from cashew nut shell, using a suggested classification of tars. The large amount of tar definitions and measurement methods, as well as the wide spectrum of organic compounds, makes it almost impossible to capture “tars” with a clear definition. And so, in order to facilitate the study of the evolution of liquid fraction composition, the compounds have been grouped according to their chemical nature, but differently from other works, it was extended the range of compounds in order to evaluate the influence of the reactor parameters in liquid fraction compositions. It is described, as well, the pyrolysis and gasification of cashew nut shell, that has been studied in a laboratory scale reactor. It was quantified and classified the production of liquids (tar) and evaluated the final temperature influence (800, 900 and 1000 °C) and the use of N2 in pyrolysis case, and a mixture of N2 and steam or air in the gasification case. Finally, it is described the identification and quantification of tar compositions, by CG-MS and CG-FID analyzes. Around 50 different compounds have been detected in the liquid fraction obtained, most of them being present at very low concentrations and it is observed that in the pyrolysis and gasification processes, phenol and benzene were the major chemical groups, and this fact agree with others works, presented here in a bibliographic revision.
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Dhal, Krishna Gopal Gopal, Mandira Sen, and Sanjoy Das. "Multi-Thresholding of Histopathological Images Using Fuzzy Entropy and Parameterless Cuckoo Search." In Critical Developments and Applications of Swarm Intelligence, 339–56. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-5134-8.ch013.
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This chapter presents a multi-level histopathological image thresholding approach based on fuzzy entropy theory. This entropy measure is maximized to obtain the optimal thresholds of the image. In order to solve this problem, one self-adaptive and parameter-less cuckoo search (CS) algorithm has been employed, which leads to an accurate convergence towards the optima within less computational time. The performance of the proposed CS is also compared with traditional CS (TCS) algorithm and particle swarm optimization (PSO). The outcomes of the proposed fuzzy entropy-based model are compared with Shannon entropy-based model both visually and statistically in order to establish the perceptible difference in image.
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Al-Jaafreh, Moha’med O., and Adel A. Al-Jumaily. "Blood Pressure Estimation with Considering of Stroke Volume Effect." In Encyclopedia of Healthcare Information Systems, 173–80. IGI Global, 2008. http://dx.doi.org/10.4018/978-1-59904-889-5.ch024.
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The mean arterial pressure (MAP) is a very important cardiovascular parameter for physicians to diagnose various cardiovascular diseases. Many algorithms were used to estimate MAP with different accuracy. These algorithms used different factors, such as blood level, pulses, and external applied pressure, photo-plethysmography (PPG) signal features, heart rate (HR), and other factors. In addition, some natural-based techniques were employed to minimize the difference between estimated and measured blood pressure, as well as to measure blood pressure continuously. This article presents an algorithm to estimate MAP, utilizing the HR, Stroke Volume (SV), and Total Peripheral Resistance (TPR), with considering SV changing influence; this consideration is investigated mathematically, and by the Particle Swarm Optimization (PSO) technique.
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Shaffiey, Sayed Reza, and Sayedeh Fatemeh Shaffiey. "Self-Setting Calcium Phosphate Bone Cement Preparation, Characterization and Drug Delivery for Skeletal System." In Advancing Medicine through Nanotechnology and Nanomechanics Applications, 184–99. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-1043-7.ch008.
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The reactivity of acid base cements forming hydroxyapatite (HA) such as, ß-tricalcium phosphate (ß-TCP) and dicalcium phosphate dehydrate (DCPD). Amorphous calcium phosphates, prepared by precipitation from supersaturated solutions, can also react to form apatitic cements since they are thermodynamic unstable with respect to HA and have a setting reaction more independent of particle size. Calcium phosphate cement containing an antibiotic can be used for filling bone defects and to ensure local antibiotherapy. Therefore, in the present chapter proposal, cement paste was prepared by combining cement liquids comprised of Na2HPO4 with cement powders. Gentamicin sulfate was also loaded on the cements and its in vitro release was evaluated over a period of time. The cement setting times were compared before and after drug addition. According to results, the initial and final setting times of samples increase after drug addition.
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Senzaki, Tatsuya, Michiaki Matsukawa, Takanori Yonai, Haruka Taniguchi, Akiyuki Matsushita, Takahiko Sasaki, and Mokoto Hagiwara. "Functional Materials Synthesis and Physical Properties." In Recent Perspectives in Pyrolysis Research. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.100241.
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A citrate pyrolysis technique is a unique route to prepare reactive precursor mixtures through an ignition process of concentrated aqueous solution. This procedure enables to synthesize highly homogeneous and fine powders for functional materials. The double-chain based superconductor Pr2Ba4Cu7O15−δ and double perovskite photocatalytic semiconductor Ba2Tb(Bi,Sb)O6 were synthesized by using the citrate pyrolysis technique. For the present sample with a reduction treatment for 72 h, a sharp superconducting transition appeared at an onset temperature Tc,on=26 K accompanied by a zero-resistance state at Tc,zero=22 K. The superconducting volume fraction estimated from the magnetization measurement showed an excellent value of ∼58%. Both reduction treatment in a vacuum and subsequent quenching procedure are needed to realize higher superconductivity due to further oxygen defects. The polycrystalline samples for Ba2Tb(Bi1−x,Sbx)O6 (x=0 and 0.5) were formed in the monoclinic and cubic crystal structures. We conducted the gaseous 2-propanol (IPA) and methylene blue (MB) degradation experiments under a visible light irradiation, to evaluate photocatalytic activities of the powder samples. For the Sb50% substituted sample, the highest performance of MB degradation was observed. The effect of Sb-substitution on the photocatalytic degradation of MB is in direct contrast to that on the IPA decomposition under visible light irradiation. The enhanced photocatalytic properties in the citrate samples are attributed to their morphology, where fine particles are homogeneously distributed with a submicron order.
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Deamer, David W. "Sources of Organic Compounds Required for Primitive Life." In Assembling Life. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190646387.003.0009.
Full textAbstract:
Carbon compounds on the early Earth were not the simple mixture previously referred to as a “prebiotic soup.” Instead, there was a continuing input of organic material synthesized by geochemical and photochemical reactions in the volcanic crust and atmosphere; organic compounds were also being delivered during late accretion by the infall of interplanetary dust particles (IDPs), impacting comets, and asteroid-sized bodies. Compounds from both sources (terrestrial and not) then underwent chemical processing by volcanism, photochemistry, and mineral-driven oxidation–reduction reactions. Some of these processes were synthetic reactions that led to increasing complexity, but this was balanced by other processes such as hydrolysis and pyrolysis that degraded organic material into simpler compounds or tar-like polymers. Because the atmosphere contained no molecular oxygen, the organic compounds that formed were relatively stable as a dilute solution in the global ocean, but were also dissolved in freshwater hydrothermal pools in contact with mineral surfaces of volcanic land masses. In either case, a process was required by which the organic compounds could become sufficiently concentrated to undergo chemical reactions. Questions to be addressed: What are plausible sources of organic compounds? What is their composition and abundance? How would organic material be chemically processed on the early Earth? How can dilute organic solutes become sufficiently concentrated to undergo chemical reactions? Chapter 1 described how virtually all of the carbon now circulating in the biosphere as organic and inorganic compounds was delivered during accretion of planetesimals as the Earth formed, and it is reasonable to assume that Mars had a similar addition of carbon compounds and water after it cooled from primary accretion. On the Earth, organic substances delivered during primary accretion would have been destroyed by the heat of impacts and the moon-forming event, so the carbon compounds necessary for the origin of life were necessarily added after the Earth had cooled sufficiently for a global ocean to appear.
Conference papers on the topic "TCR particles"
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Eda, Takeshi, Achyut Sapkota, Jun Haruta, Masayuki Nishio, and Masahiro Takei. "Investigation of Transition Boundary and Nature of Pulsating Flow in the Trickle Bed Reactors by Electrical Resistance Tomography." In 2013 21st International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icone21-16149.
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A fixed bed reactor that operates in gas-liquid co-current down flow is called Trickle Bed Reactor (TBR). It is widely used in chemical engineering. And, recently used in purification of radioactive contamination from contaminated water generated in the Fukushima Daiichi nuclear power plant. There are several flow conditions that occur in the TBR due to gas and liquid flow rate. Since mass and heat transfer rate and particles wetting depend on flow condition, it is necessary to establish the visualization techniques to understand flow condition, transition boundary and properties of gas liquid flow in TBR. In this study, authors employed the lab-scale TBR, made of 100mm inner diameter acrylic column, packed with particles of two sizes (3, 5 mm) that are used in the actual reactor. Water and air were injected from the top of the column and cross-sectional liquid distribution was captured at the bottom of the column by electrical resistance tomography (ERT). ERT is a tomographic technique that provides the cross-sectional conductivity distribution at the rate of about 50 frames per second by injecting current and measuring voltages between the 16 electrodes that are attached around the column. By analyzing the spatial and temporal characteristics of the liquid distribution obtained by ERT, it was found that particle size has only little impact on induction of pulsating flow and larger particle causes distinct pulses. Smaller particle causes blurred tiny pulses due to higher flow resistance. Larger particle (5 mm) is advantageous for pulsating flow.
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Hao, Zihan, Xing Yang, Xiangyu Wang, and Zhenping Feng*. "URANS Simulations of Deposition in a Rotor Passage of the First-Stage Turbine for an Aero-Engine." In GPPS Xi'an21. GPPS, 2022. http://dx.doi.org/10.33737/gpps21-tc-130.
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Atmospheric particulate pollutants in high-temperature and high-speed gas are prone to deposit in aero-engine turbines. The deposition changes the blade profile, resulting in a degradation of aerodynamic performance, increases surface roughness and blocks film cooling holes and internal cooling channels, thus reducing the cooling performance of the blade. Therefore, the blades are easily ablated, especially for the rotating parts as they have high rotating speed. In present study, unsteady numerical simulations were performed to investigate the effects of particle deposition by studying the movement patterns and deposits distributions of particles in the rotor passages. The effects of rotating speed, tip clearance, and cavity depth on the movement and deposition of contaminant particles were illustrated. Results show that the deposition on the blade surfaces varies with the rotating speeds and the rotor tip clearances. The deposits are mainly concentrated on the pressure side of the blade where multiple rebounds of the particles are observed under a cruise operating condition. More particles flow into the tip clearance carried by the stronger leakage flow resulted from a larger tip clearance, and the squealer tip increases the capture efficiency of the particles on the blade tip.
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Lawson, C. M., R. R. Michael, and G. W. Euliss. "Nanosecond transmission to total internal reflection switching/limiting via laser-induced cavitation in carbon suspensions." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/oam.1991.thmm47.
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We have experimentally demonstrated nanosecond transmission to total internal reflection (TIR) switching and optical limiting resulting from laser induced cavitation in films of carbon microparticles suspended in ethanol. The films are bounded by two glass windows separated by mylar spacers. Laser-induced cavitation occurs when the fraction of the incident energy absorbed by a carbon particle is sufficient to heat up and vaporize a small volume of the surrounding liquid. These small vapor bubbles coalesce to form larger vapor bubbles. Total internal reflection switching/limiting occurs at the glass-vapor interface that is formed when these bubbles meet the glass substrate. Nonlinear refractive-index changes as large as 0.3 have been obtained using a single 5-ns Q-switched doubled (532-nm) Nd:YAG laser pulse. Switching and limiting thresholds as low as 0.2 J/cm2 have been measured. More than 90% of the incident energy has been reflected using the cavitation/TIR switching mechanism. The observed limiting results from two mechanisms: energy removal via TIR and scattering from microplasmas that form when the carbon particles are thermally ionized by the incident laser energy. We have investigated the effects that particle concentration, film thick ness and film bias temperature have on the cavitation/TIR process and limiting behavior.
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Feng, Mingjun, Wu Zhou, and Fangting Wang. "Application of particle streak velocimetry based on binocular vision in cascade flow channel." In GPPS Xi'an21. GPPS, 2022. http://dx.doi.org/10.33737/gpps21-tc-122.
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Particle streak velocimetry (PSV) has become one of the important branches of measurement methods for fluid flow. A new kind of particle streak velocimetry method based on binocular vision and single-frame multi-exposure technology is proposed. The direction of the flow is judged by the combination of short and long exposures, the gray-level fitting method is used to identify the trajectory features. This method uses nearest neighbor matching and angle of inclination constraints to match and sort multiple trajectories of the same particle, uses epipolar constraints to accomplish binocular matching based on trajectory feature points, and adopts B-spline fitting on the three-dimensional reconstructed feature points to calculate the three-dimensional velocity of particles. The actual measurement of the fluid flow in a gas pipeline shows that this method can be reliably used for unsteady flow measurement.
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Watanabe, M., C. Brauns, M. Komatsu, S. Kuroda, H. Katanoda, F. Gärtner, and T. Klassen. "Effect of Nitrogen Flow Rate on Mechanical Properties of Metallic Coatings by Warm Spray Deposition." In ITSC2011, edited by B. R. Marple, A. Agarwal, M. M. Hyland, Y. C. Lau, C. J. Li, R. S. Lima, and A. McDonald. DVS Media GmbH, 2011. http://dx.doi.org/10.31399/asm.cp.itsc2011p0260.
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Abstract In Warm Spraying (WS), the temperature of the combustion flame is reduced and controlled by injecting nitrogen gas into the combustion flame before the injection of spray powders. Thus, temperatures of spray particles are kept under their melting points with moderately heated and thermally softened states. As compared to HVOF-spraying, the oxidation of particles can be significantly suppressed due to lower deposition temperatures, whereas, as compared to cold spraying, the degree of particle deformation upon impact can be enhanced by attaining higher particle temperatures. In the present study, Ti, Cu, and Al coatings were fabricated by WS under various nitrogen flow rates. The mechanical properties of the coatings were evaluated by tubular coating tensile (TCT) and micro flat tensile (MFT) tests. For the lower impact temperature regime, the coatings became denser and the ultimate strengths of Ti or Cu coatings increased reaching a maximum by decreasing the nitrogen flow rates. A further decrease of nitrogen flow rates and reaching the upper temperature regime reduced the coating strength. These results clearly demonstrate how particle temperatures affect the microstructures and mechanical properties of WS coatings and that optimum spray conditions have to be balanced between softening and oxidation by adjusting particle temperatures.
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Wimmer, Markus A. "Does the Load Carrying Capacity of Third Bodies Affect Contact Conditions in Total Knee Replacement (TKR)?" In ASME 1999 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/imece1999-0364.
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Abstract Third-body wear is a frequently reported phenomenon in TKR, however, little attention has been paid to the load carrying capacity of third bodies. It may be possible that these particles accumulate to a quantity, sufficient to separate the articulating surfaces of the bearing. To address this question, the particle number for a complete separation was theoretically determined and compared to realistic values. Based on the results, a total separation of the artificial knee articulation appears likely and should be considered when interpreting surface wear based on common stress analyses. This seems to be reflected by clinical observation that flat tibial components do not wear faster than dished ones.
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Haseli, Y., J. A. van Oijen, and L. P. H. de Goey. "Mathematical Modeling of Heat and Mass Transfer Processes During Pyrolysis and Combustion of a Single Biomass Particle." In ASME 2012 Heat Transfer Summer Conference collocated with the ASME 2012 Fluids Engineering Division Summer Meeting and the ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ht2012-58096.
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A detailed mathematical model is developed for simulation of heat and mass transfer processes during the pyrolysis and combustion of a single biomass particle. The kinetic scheme of Shafizadeh and Chin is employed to describe the pyrolysis process. The light gases formed during the biomass pyrolysis is assumed to consist of methane, carbon dioxide, carbon monoxide, hydrogen and water vapor with given mass fractions relevant to those found in the experiments of high heating conditions. The combustion model takes into account the reactions of oxygen with methane, hydrogen, carbon monoxide, tar and char as well as gasification of char with water vapor and carbon dioxide. Appropriate correlations taken from past studies are used for computation of the rate of these reactions. The model allows calculation of time and space evolution of various parameters including biomass and char densities, gaseous species and temperature. Different experimental data reported in the literature are employed to validate the pyrolysis and combustion models. The reasonable agreement obtained between the predictions and measured data reveals that the presented model is capable of successfully capturing various experiments of wood particle undergoing a pyrolysis or combustion process. In particular, the role of gas phase reactions within and adjacent to particle on the combustion process is examined. The results indicate that for the case of small particles in the order of millimeter size and less, one may neglect any effects of gas phase reactions. However, for larger particles, a combustion model may need to include hydrogen oxidation and even carbon monoxide combustion reactions.
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Kim, Hwang Suk, Hwansung Lee, Jiwoon Song, Hokyu Moon, Hyung Hee Cho, Yoon-sub Chung, and Yeon-seok Park. "Numerical Analysis of Two-Phase Flow in Fluidized Bed Reactor With Jet Nozzle for Polysilicon Growth." In ASME-JSME-KSME 2011 Joint Fluids Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajk2011-14009.
Full textAbstract:
The present study has been conducted on three dimensional flow characteristics between poly-silicon particles and gas in a large scale fluidization bed reactor (FBR). This study was mainly performed numerically by commercial code Fluent. The Eulerian multiphase model was used to simulate hydrodynamics of bubbling fluidized bed. The size of silicon particle was 1000 μm and 2000 μm, and density was 2329 kg/m3. The reactor chamber had base gas flow from bottom porous plate and reacting flow from the jet nozzles (single or multi) with high velocity. The base gas and reacting gas were hydrogen (H2) and trichloro-silane (TCS) respectively. The TCS mole fraction was controlled to 13% and 20% of total gas amount. From the simulation, performance and design parameters were evaluated on single and multi nozzles jet related to flow mixing characteristics and a gas-solid contact performance. As a result, considering of the mixing characteristics between the gas and the solid, multi nozzle jets much improved the mixing performance in the reacting zone. In addition, the widespread distribution of TCS which led to better gas-solid contact performance were showed by the multi nozzle jets. This CFD data will provide useful basis to predict fluidization characteristics in the poly-silicon FBR process.
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Kessler, Daniel, Jens Friedrichs, and Christian Werner-Spatz. "ON THE IMPACT OF FOULING ON THE STAGE INTERACTION IN A 2.5-STAGE COMPRESSOR." In GPPS Chania22. GPPS, 2022. http://dx.doi.org/10.33737/gpps22-tc-34.
Full textAbstract:
Jet engines and thus the compressor suffer operational, particle-based wear during their usage. The type of wear depends on the ambient conditions, the operating point, and the size of the particles. Fouling is one possible type of wear, consisting of the deposition of small particles on the blade’s surface together with moisture from the air or leaked fluids of the compressor, thereby increasing the surface roughness and the blade thickness. In order to better understand the effects of fouling, and especially the interaction of different affected compressor stages, investigations are carried out on a 2.5-stage test compressor to evaluate fouling in the compressor. Fouling is represented using a randomly distributed surface structure of hemispheres on both rotor rows. The roughness parameter Ra is based on surface measurements of a worn actual CFM-56 engine after operation. The results are compared to smooth rotor blades without coating. The effect on the compressor is evaluated by integral measurements of efficiency and pressure rise and by wake measurements with pneumatic 5-hole probes. The results show integral losses in efficiency and pressure rise and, depending on the combination of rough rotor rows, a redistribution of the stage work. The second stage compensates for some of the losses of a rough first stage rotor, reducing the negative effects of the fouling.
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Xu, Yi, and Qiaomei Liang. "Sports Video Target Tracking Algorithm Based on Optimized Particle Swarm Algorithm." In 2021 International Conference on Information Technology and Contemporary Sports (TCS). IEEE, 2021. http://dx.doi.org/10.1109/tcs52929.2021.00096.
Full textReports on the topic "TCR particles"
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Chrisey, Douglas B. The Effect of Energetic Charged Particle Bombardment on the Properties of Thin Films of High Tc Superconductors. Fort Belvoir, VA: Defense Technical Information Center, October 1988. http://dx.doi.org/10.21236/ada199883.
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Friedman, Shmuel, Jon Wraith, and Dani Or. Geometrical Considerations and Interfacial Processes Affecting Electromagnetic Measurement of Soil Water Content by TDR and Remote Sensing Methods. United States Department of Agriculture, 2002. http://dx.doi.org/10.32747/2002.7580679.bard.
Full textAbstract:
Time Domain Reflectometry (TDR) and other in-situ and remote sensing dielectric methods for determining the soil water content had become standard in both research and practice in the last two decades. Limitations of existing dielectric methods in some soils, and introduction of new agricultural measurement devices or approaches based on soil dielectric properties mandate improved understanding of the relationship between the measured effective permittivity (dielectric constant) and the soil water content. Mounting evidence indicates that consideration must be given not only to the volume fractions of soil constituents, as most mixing models assume, but also to soil attributes and ambient temperature in order to reduce errors in interpreting measured effective permittivities. The major objective of the present research project was to investigate the effects of the soil geometrical attributes and interfacial processes (bound water) on the effective permittivity of the soil, and to develop a theoretical frame for improved, soil-specific effective permittivity- water content calibration curves, which are based on easily attainable soil properties. After initializing the experimental investigation of the effective permittivity - water content relationship, we realized that the first step for water content determination by the Time Domain Reflectometry (TDR) method, namely, the TDR measurement of the soil effective permittivity still requires standardization and improvement, and we also made more efforts than originally planned towards this objective. The findings of the BARD project, related to these two consequential steps involved in TDR measurement of the soil water content, are expected to improve the accuracy of soil water content determination by existing in-situ and remote sensing dielectric methods and to help evaluate new water content sensors based on soil electrical properties. A more precise water content determination is expected to result in reduced irrigation levels, a matter which is beneficial first to American and Israeli farmers, and also to hydrologists and environmentalists dealing with production and assessment of contamination hazards of this progressively more precious natural resource. The improved understanding of the way the soil geometrical attributes affect its effective permittivity is expected to contribute to our understanding and predicting capability of other, related soil transport properties such as electrical and thermal conductivity, and diffusion coefficients of solutes and gas molecules. In addition, to the originally planned research activities we also investigated other related problems and made many contributions of short and longer terms benefits. These efforts include: Developing a method and a special TDR probe for using TDR systems to determine also the soil's matric potential; Developing a methodology for utilizing the thermodielectric effect, namely, the variation of the soil's effective permittivity with temperature, to evaluate its specific surface area; Developing a simple method for characterizing particle shape by measuring the repose angle of a granular material avalanching in water; Measurements and characterization of the pore scale, saturation degree - dependent anisotropy factor for electrical and hydraulic conductivities; Studying the dielectric properties of cereal grains towards improved determination of their water content. A reliable evaluation of the soil textural attributes (e.g. the specific surface area mentioned above) and its water content is essential for intensive irrigation and fertilization processes and within extensive precision agriculture management. The findings of the present research project are expected to improve the determination of cereal grain water content by on-line dielectric methods. A precise evaluation of grain water content is essential for pricing and evaluation of drying-before-storage requirements, issues involving energy savings and commercial aspects of major economic importance to the American agriculture. The results and methodologies developed within the above mentioned side studies are expected to be beneficial to also other industrial and environmental practices requiring the water content determination and characterization of granular materials.