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Journal articles on the topic "PBT"
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Adedayo, Sosina. "Need Assessment of Farmers in Crop-Livestock Production Systems in Ido Local Government Area, Oyo State, Nigeria." International Journal of Agricultural Extension 7, no. 2 (2019): 177–86. http://dx.doi.org/10.33687/ijae.007.02.2730.
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Agricultural projects and programmes funded by governments and donor agencies often failed to achieve the desired set objective(s) at the system levels. The study tries to assess the existing production practices with a view of coming up with a consensus farmer need in a crop-livestock production system at Ido Local Government Area (LGA). The study used a three-stage-sampling technique to elicit information from 225 respondents. Ido Local Government Area was purposively selected for the study. Three cells were randomly selected for the research, three villages were randomly selected in each cell and twenty-five farmers were selected using the snowball selection technique. The data obtained from the Participatory Rural Appraisal were analyzed using descriptive statistics. The pairwise ranking tool helped in determining the importance of the identified problems from the FGD in the study area. The researcher identified the following problems (Pb) from the focus group discussion; inadequate capital for livestock production (Pb1), poor housing for livestock (Pb2), inadequate nutrition for livestock (Pb3), diseases of crops (Pb4), livestock and predatory attack on crops (Pb5). The pairwise comparison of percentage of Pb1 versus (vs) Pb2 was 80/20%, Pb1 vs Pb3 was 68/32%, Pb1 vs Pb4 was 80/20%, Pb1 vs Pb5 was 12/88%, Pb2 vs Pb3 was 68/32%, Pb2 vs Pb4 was 20/80%, Pb2 vs Pb5 was 20/80%, Pb3 vs Pb4 was 32/68%, Pb3 vs Pb5 was 20/80%, vs Pb4 vs Pb5 was 20/80% respectively. The ultimate farmers’ problem in crop-livestock production systems (CLPS) that needs immediate intervention and technical assistance was inadequate capital as perceived from the responses of the farmers.
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Mendoza-Wilson, Ana María, and René Renato Balandrán-Quintana. "Effect of Constituent Units, Type of Interflavan Bond, and Conformation on the Antioxidant Properties of Procyanidin Dimers: A Computational Outlook." Journal of Chemistry 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/3535148.
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Procyanidin (PC) dimers are powerful antioxidants, abundant in plant tissues, and also bioavailable. However, the role of the molecular structure of PCs on their antioxidant properties is still a controversial and not fully understood issue that needs to be addressed in a more specific way. The objective of this study was to analyze the effect of the constituent units, type of interflavan bond, and conformation on the antioxidant properties of PC dimers including PB3, PB4, PB5, PB6, PB7, and PB8, using the density functional theory (DFT) computational method. The analysis was performed in function of parameters that allow determining the ability of the molecules to transfer or to capture electrons, among which the chemical potential, bond dissociation enthalpy (BDE), gap energy, Fukui indices, and charge distribution of HOMO-LUMO orbitals. The factors that showed the most notable effects on the antioxidant properties of the PC dimers were the type of interflavan bond and the conformation. The antioxidant ability of the dimers PB3 and PB4 containing the interflavan bond C4–C8, in their Compact conformation, was very similar to each other but greater than those of dimers PB5, PB6, PB7, and PB8 containing the C4–C6 interflavan bond. PB8 showed the lowest antioxidant ability.
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Sosina, A. O., and O. J. Babayemi. "Assessment of farmers' needs in Ibarapa East Local Government area of Oyo State, Nigeria." Nigerian Journal of Animal Production 47, no. 5 (2020): 92–100. http://dx.doi.org/10.51791/njap.v47i5.1352.
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Government and non-government organizations (NGOs) interventions to local farmers in the recent past had not yielded the desired result because these interventions were not tailored towards the needs of farmers. However, most information on the needs of target farmers have been very scanty thus, the need to use a bottom top approach to assess farmers' needs in Ibarapa East, Oyo state. A three-stage sampling technique was used to purposively select about 225 respondents. Parameters measured were household characteristics, farm sizes, farm labor availability, seasonal pattern and need to be assessed using a participatory rural appraisal approach comprising of focus group discussion (FGD) and structured questionnaire. Data were analyzed descriptively and the need assessed using the pair-wise ranking and simple matrix. Of challenges listed in FDG among crop-livestock farmers, only five (5) were prioritized as follows; wastage of agricultural products (Pb1), bad road network (Pb2), high cost of agricultural inputs (Pb3), lack of potable water (Pb4) and animal invasion (Pb5). The pairwise comparison of the percentage of Pb1 versus (vs.) Pb2 was 80/20%, Pb1 vs. Pb3 was 90/10%, Pb1 vs. Pb4 was 70/30%, Pb1 vs. Pb5 was 20/80%, Pb2 vs. Pb3 was 70/30%, Pb2 vs Pb4 was 30/70%, Pb2 vs. Pb5 was 10/90%, Pb3 vs. Pb4 was 20/80%, Pb3 vs. Pb5 was 10/90%, vs. Pb4 vs Pb5 was 30/70%, respectively. There were proffered solutions to the problem(s) itemized by the FGD. The animal invasion was ranked highest as farmers' need assessed for possible intervention in Ibarapa East. Governments and NGO funds should be addressing animal invasion for desirable project impact assessment. Les interventions des gouvernements et des organisations non gouvernementales (ONG) auprès des agriculteurs locaux dans un passé récent n'avaient pas donné le résultat souhaité car ces interventions n'étaient pas adaptées aux besoins des agriculteurs. Cependant, la plupart des informations sur les besoins des agriculteurs cibles ont été très rares, ce qui nécessite d'utiliser une approche ascendante pour évaluer les besoins des agriculteurs de l'est d'Ibarapa, dans l'État d'Oyo. Une technique d'échantillonnage en trois étapes a été utilisée pour sélectionner environ 225 répondants. Les paramètres mesurés étaient les caractéristiques des ménages, la taille des exploitations, la disponibilité de la main-d'oeuvre agricole, le profil saisonnier. Ils doivent être évalués à l'aide d'une approche d'évaluation rurale participative comprenant des discussions de groupe et un questionnaire structuré. Les données ont été analysées de manière descriptive et le besoin évalué en utilisant le classement par paires et une matrice simple. Parmi les défis énumérés dans le 'FDG' chez les agriculteurs et les éleveurs, seuls cinq (5) ont été classés comme suit; gaspillage des produits agricoles (le 'Pb' 1), mauvais réseau routier (le 'Pb' 2), coût élevé des intrants agricoles (le 'Pb' 3), manque d'eau potable (le 'Pb' 4) et invasion animale (le 'Pb' 5). La comparaison par paire du pourcentage de 'Pb' 1 versus (vs) 'Pb' 2 était de 80/20%, Pb1 vs Pb3 était de 90/10%, Pb1 vs Pb4 était de 70/30%, Pb1 vs Pb5 était de 20/80% Pb2 vs Pb3 était de 70/30%, le 'Pb' 2 vs le 'Pb4' était de 30/70%, le 'Pb' 2 vs le 'Pb' 5 était de 10/90%, le 'Pb' 3 vs. le 'Pb' 4 était de 20/80%, le 'Pb' 3 vs. le 'Pb' 5 etaient 10/90%,vs le 'Pb' 4 vs le 'Pb'5 était respectivement de 30/70%. Des solutions ont été proposées au (x) problème (s) détaillé (s) par le FGD. L'invasion animale a été classée au premier rang des besoins des agriculteurs évalués pour une éventuelle intervention à l'Estd'Ibarapa. Les gouvernements et les fonds d'ONG devraient s'attaquer à l'invasion animale pour une évaluation de l'impact souhaitable du projet.
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Ntita, Mbaya, Shin-Ichi Inoue, Jiun-Yu Jian, et al. "Type I interferon production elicits differential CD4+ T-cell responses in mice infected with Plasmodium berghei ANKA and P. chabaudi." International Immunology 34, no. 1 (2021): 21–33. http://dx.doi.org/10.1093/intimm/dxab090.
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Abstract Abstract Plasmodium parasites that infect humans are highly polymorphic, and induce various infections ranging from an asymptomatic state to life-threatening diseases. However, how the differences between the parasites affect host immune responses during blood-stage infection remains largely unknown. We investigated the CD4+ T-cell immune responses in mice infected with P. berghei ANKA (PbA) or P. chabaudi chabaudi AS (Pcc) using PbT-II cells, which recognize a common epitope of these parasites. In the acute phase of infection, CD4+ T-cell responses in PbA-infected mice showed a lower involvement of Th1 cells and a lower proportion of Ly6Clo effector CD4+ T cells than those in Pcc-infected mice. Transcriptome analysis of PbT-II cells indicated that type I interferon (IFN)-regulated genes were expressed at higher levels in both Th1- and Tfh-type PbT-II cells from PbA-infected mice than those from Pcc-infected mice. Moreover, IFN-α levels were considerably higher in PbA-infected mice than in Pcc-infected mice. Inhibition of type I IFN signaling increased PbT-II and partially reversed the Th1 over Tfh bias of the PbT-II cells in both PbA- and Pcc-infected mice. In the memory phase, PbT-II cells in PbA-primed mice maintained higher numbers and exhibited a better recall response to the antigen. However, recall responses were not significantly different between the infection groups after re-challenge with PbA, suggesting the effect of the inflammatory environment by the infection. These observations suggest that the differences in Plasmodium-specific CD4+ T-cell responses between PbA- and Pcc-infected mice were associated with the difference in type I IFN production during the early phase of the infection.
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Chaiwat, Weerawut, Pimonpan Inthapat, Suwanna Boontanon, et al. "PRODUCTION OF TORREFIED BIOMASS PELLETS FROM WOODY AND AGRICULTURAL RESIDUES (TIChE2021)." Suranaree Journal of Science and Technology 30, no. 3 (2023): 010232(1–13). http://dx.doi.org/10.55766/sujst-2023-03-e0912.
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Two different combined process sequences of biomass pretreatment between pelletization after torrefaction (PAT) and pelletization before torrefaction (PBT) were comparatively investigated to produce torrefied biomass pellets (TBP) from woody biomasses, e.g. Leucaena (LC) and rubberwood (RW), and agricultural residues, e.g. rice straw (RS) and sugarcane leaves (SCL). In this study, each sample was thermally treated at 260-300°C for 5 min during torrefaction process. It was found that both woody biomasses and agricultural residues had mass yield lower than 63wt%, while the bulk density of TBPs were improved higher than 400kg/m3. For equilibrium moisture content (EMC) analysis, TBPs via PBT method had lower EMC than raw pellet after being kept at 30°C for 12 days. For the thermochemical properties, the TBPs had higher FC, %C, and HHVs than raw pellets in all biomasses and increased with torrefaction temperature. When comparing the TBPs between PAT and PBT torrefied pellets, the HHVs of PBT torrefied pellets at 300°C were achieved highest at 27 MJ/kg for SCL sample, leading to lower H/C and O/C ratio closely to that of lignite. In addition, the combustion performance index (Sn) of PAT and PBT torrefied pellets was lower than raw pellets, showing a similar property as coal and lignite. Briefly, this study suggests using PBT pretreatment process to produce high quality solid fuel, particularly for agricultural residues such as SCL for a potential substitute of currently used coal.
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Xu, Jian Lin, Bing Xue Ma, Cheng Hu Kang, Cheng Cheng Xu, Zhou Chen, and Yong Gang Lin. "Thermal Decomposition Kinetics of Flame Retardant Polybutylene Terephthalate Matrix Composites." Materials Science Forum 956 (June 2019): 181–91. http://dx.doi.org/10.4028/www.scientific.net/msf.956.181.
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The thermal decomposition kinetics of polybutylene terephthalate (PBT) and flame-retardant PBT (FR-PBT) were investigated by thermogravimetric analysis at various heating rates. The kinetic parameters were determined by using Kissinger, Flynn-Wall-Ozawa and Friedman methods. The y (α) and z (α) master plots were used to identify the thermal decomposition model. The results show that the rate of residual carbon of FR-PBT is higher than that of PBT and the maximum mass loss rate of FR-PBT is lower than that of PBT. The values of activation energy of PBT (208.71 kJ/mol) and FR-PBT (244.78 kJ/mol) calculated by Kissinger method were higher than those of PBT (PBT: 195.54 kJ/mol) and FR-PBT (FR-PBT: 196.00 kJ/mol) calculated by Flynn-Wall-Ozawa method and those of PBT and FR-PBT (PBT: 199.10 kJ/mol, FR-PBT: 206.03 kJ/mol) calculated by Friedman methods. There is a common thing that the values of activation energy of FR-PBT are higher than that of PBT in different methods. The thermal decomposition reaction models of the PBT and FR-PBT can be described by Avarami-Erofeyev model (A1).
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Shin, Hyeyoung, and Eun-Soo Park. "Mechanical and dielectric breakdown properties of PBT/TPE, PBT/PBT/PET, and PBT/antioxidant blends." Journal of Applied Polymer Science 114, no. 5 (2009): 3008–15. http://dx.doi.org/10.1002/app.30930.
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Wei, Xi, Chunyang Zhang, Depeng Gong, et al. "A Study on the Impermeability of Nanodispersible Modified Bentonite Based on Colloidal Osmotic Pressure Mechanisms and the Adsorption of Harmful Substances." Nanomaterials 13, no. 12 (2023): 1840. http://dx.doi.org/10.3390/nano13121840.
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With the growing demands of human beings, sanitary landfill, along with the increase in landfill depth and leachate water pressure, has put forward new and higher requirements for the impermeable layer. In particular, it is required to have a certain adsorption capacity of harmful substances from the perspective of environmental protection. Hence, the impermeability of polymer bentonite–sand mixtures (PBTS) at different water pressure and the adsorption properties of polymer bentonite (PBT) on contaminants were investigated through the modification of PBT using betaine compounded with sodium polyacrylate (SPA). It was found that the composite modification of betaine and SPA could reduce the average particle size of PBT dispersed in water (reduced to 106 nm from 201 nm) and enhance the swelling properties. As the content of SPA increased, the hydraulic conductivity of PBTS system decreases and the permeability resistance improves, while the resistance to external water pressure increases. It is proposed a concept of the potential of osmotic pressure in a constrained space to explain the impermeability mechanism of PBTS. The potential of osmotic pressure obtained by linear extrapolation of the trendline of colloidal osmotic pressure versus mass content of PBT could represent the external water pressure that the PBT resist. Additionally, the PBT also has a high adsorption capacity for both organic pollutants and heavy metal ions. The adsorption rate of PBT was up to 99.36% for phenol; up to 99.9% for methylene blue; and 99.89%, 99.9%, and 95.7% for low concentrations of Pb2+, Cd2+, and Hg+, respectively. This work is expected to provide strong technical support for the future development in the field of impermeability and removal of hazardous substances (organic and heavy metals).
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Wang, Ping, Li Hua Cheng, and Jian Qing Zhao. "Study on the Reaction and Thermo-Physical Properties of PC and PBT Blend." Advanced Materials Research 472-475 (February 2012): 1831–36. http://dx.doi.org/10.4028/www.scientific.net/amr.472-475.1831.
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Blends of polycarbonate (PC) and poly(butylene terephthalate) (PBT) were investigated. For 40 wt % PBT, it forms a continuous phase, the glass transition temperature (Tg) shifts to the lower temperature region. This direct comparison of XRD patterns of pure PBT and PBT containing 1.1% TPPi studied the impact of the crystallization of PBT and TPPi. We can see that diffraction peaks of XRD diagram of PBT/TPPi were broadened. When PBT content was added to 1.1% TPPi, the FWHM increases from 3.8 to 4.2 when diffraction angle was in the range of 16.9 degrees to 17.1 degrees. Thus, the addition of TPPi resulted in the small spherulite size of PBT phase, thus elaborating the sample transparency phenomenon.
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Yoo, Gyu Sang, Jeong Il Yu, Hee Chul Park, et al. "Do Biliary Complications after Proton Beam Therapy for Perihilar Hepatocellular Carcinoma Matter?" Cancers 12, no. 9 (2020): 2395. http://dx.doi.org/10.3390/cancers12092395.
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We aimed to evaluate the biliary complications and efficacy of proton beam therapy (PBT) for hepatocellular carcinoma (HCC). We retrospectively analyzed 167 patients who received PBT with ≥ 75 GyRBE of biological effective dose with ?/β = 10 for primary HCC. The perihilar region was defined as a 1-cm area extending from the right, left, and common hepatic ducts, including the gallbladder and cystic duct. PBT-related biliary complications were defined as follows: significant elevation in bilirubin level to > 3.0 mg/dL; elevation to more than twice of the baseline level after the completion of PBT; or newly developed radiological biliary abnormalities, which were not caused by HCC progression, comorbidities, or other treatments. Eighty (47.9%) had perihilar HCC. PBT-related events occurred in seven (4.2%), three of whom had perihilar HCC. Radiologic biliary abnormalities developed in 12 patients (7.2%); however, no events were PBT-related. All patients who experienced PBT-related biliary complications had underlying liver cirrhosis. The albumin-bilirubin grade was identified as an independent factor associated with PBT-related biliary complications. PBT at the current dose showed a low rate of PBT-related biliary complications even for patients with perihilar HCC. PBT for HCC patients with risk factors requires attention to reduce PBT-related biliary complications.
Dissertations / Theses on the topic "PBT"
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Ito, Edson Noriyuki. "Estudos microrreológicos da blenda PBT/SAN." Universidade Federal de São Carlos, 2006. https://repositorio.ufscar.br/handle/ufscar/647.
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Previous issue date: 2006-09-22<br>Financiadora de Estudos e Projetos<br>This work was motivated by the need of a better understanding of the
microrheological characteristics of polybutylene terephthalate, PBT, polymer
blends, such as the matrix phase PBT and the styrene-acrylonitrile, SAN
copolymer as dispersed phase. The main purpose of the microrheological
studies carried out was to analyze the rheological behavior and the morphology,
as well as their correlation, in the preparation of the PBT/SAN immiscible blend,
with and without the use of an interfacial compatibilizer. The rheological
behavior was analyzed by torque rheometry, rotational rheometry with parallelplates
geometry, and capillary rheometry. The interfacial tensions were
measured by the modified ellipsoidal drop retraction method, using an optical
polarized light microscope coupled to a hot stage. Two complementary
techniques were used in the morphological analyses: scanning electron
microscopy (SEM) with tetrahydrofuran (THF) extraction of the dispersed
phase, and transmission electron microscopy (TEM) with rutene tetroxide
(RuO4) deposition in the dispersed phase. The interfacial tension between the
PBT polymer and the SAN copolymer was found to increase as the molar mass
of the PBT increased. The use of rotational rheometry with parallel plates at low
shear rates allowed the increase in viscosity to be quantified as a function of the
reaction of the polymeric macromolecules in the PBT/SAN blend compatibilized
or not with the interfacial compatibilizer, the MMA-GMA-EA copolymer. Based
on the morphological characterizations, an analysis was made of the fibril
formation mechanisms, break up and coalescence of the particles of dispersed
phase and their interactions with the addition of interfacial compatibilizers. The
rotational rheometry at low shear rates proved to be extremely efficient in the
analysis of blend compatibilization, which is usually analyzed by torque
rheometry. It was checked that, at high shear rates, the viscosity ratio
influenced the formation of more finely dispersed phases.<br>O motivo que levou à realização deste trabalho de doutorado consistiu
na necessidade de um melhor entendimento das características
microrreológicas de blendas poliméricas constituídas de poli(tereftalato de
butileno), PBT, como fase matriz, e do copolímero estireno-acrilonitrila, SAN,
como fase dispersa. Os estudos microrreológicos realizados tiveram como
enfoque principal analisar o comportamento reológico e a morfologia, bem
como suas correlações na preparação da blenda imiscível PBT/SAN, com e
sem a utilização de um compatibilizante interfacial. Nas análises do
comportamento reológico, foram utilizadas reometria de torque, reometria
rotacional na geometria de placas paralelas e reometria capilar. As medidas de
tensões interfaciais foram realizadas através do método de retração de gotas
elipsoidais modificado, utilizando-se de um microscópio óptico com luz
polarizada acoplado a um estágio a quente. Nas análises morfológicas, foram
utilizadas duas técnicas complementares, através de microscopia eletrônica de
varredura (MEV) com extração da fase dispersa com tetrahidrofurano (THF) e
por microscopia eletrônica de transmissão (MET) com a deposição de tetróxido
de rutênio (RuO4) sobre a fase dispersa. Utilizando-se do método de retração
de gota modificado, verificou-se que a tensão interfacial entre o polímero PBT e
o copolímero SAN aumenta com o aumento da massa molar do PBT.
Utilizando-se da reometria de placas paralelas a baixas taxas de cisalhamento,
foi possível quantificar o aumento de viscosidade em função da reação das
macromoléculas poliméricas na blenda PBT/SAN, compatibilizada ou não com
o agente de compatibilização interfacial (o terpolímero metacrilato de metilametacrilato
de glicidila-acrilato de etila, MMA-GMA-EA). Por meio das
caracterizações morfológicas, foi possível analisar os mecanismos de formação
de fibrilas, cominuição e coalescência das partículas de fase dispersa e de
suas interações com a adição de agentes de compatibilização interfacial. A
técnica de reometria rotacional de placas paralelas em baixas taxas de
cisalhamento mostrou-se extremamente eficiente na análise de
compatibilização de blendas, que, na maioria das vezes, é feita através de reometria de torque. Verificou-se que, a altas taxas de cisalhamento, a razão
de viscosidade influencia a formação de fases mais finamente dispersas em
função da taxa de cisalhamento aplicada à blenda PBT/SAN.
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Freitas, Cássia Alves de. "Nanocompósitos poliméricos de poli (tereftalato de butileno) - PBT." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-20082010-163925/.
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Neste trabalho, nanocompósitos de PBT, poli(tereftalato de butileno) e argila brasileira montmorilonita (MMT) modificada organicamente, foram obtidos com e sem agente tenacificante. Sais quaternários de amônio e fosfônio com estruturas químicas diferentes foram utilizados para modificar as argilas. Nanocompósitos de PBT com argilas comerciais, dos Estados Unidos, modificadas com de sais de amônio, foram obtidos para comparação das propriedades. As argilas e os polímeros foram misturados utilizando um misturador e uma extrusora dupla rosca, acoplados a um reômetro de torque. A qualidade da troca catiônica foi avaliada por difração de Raios-X (XRD), inchamento em solventes e análises termogravimétricas (TGA). O estado das argilas modificadas (OMMT) na matriz de PBT foi avaliado por XRD, microscopia ótica e microscopia eletrônica de transmissão (TEM). A dispersão do agente tenacificante foi avaliada por microscopia eletrônica de varredura (SEM). As propriedades mecânicas e de flamabilidade também foram avaliadas. Os resultados de flamabilidade foram explicados com ensaios de (TGA). Os resultados de espaçamento basal obtidos por XRD e inchamento em solventes foram dependentes da arquitetura do sal quaternário utilizado. Os espaçamentos basais ficaram maiores para os sais quaternários de longas cadeias alquílicas. Entretanto, o sal quaternário em excesso não foi eliminado na lavagem. A maior estabilidade térmica foi obtida com sais quaternários de fosfônio. Após a adição ao PBT, foi observado que a adição da argila organofílica na matriz polimérica não contribuiu para a significativa melhora das propriedades mecânicas que, em alguns casos, foram inferiores àquelas do PBT. Entretanto, a retardância a chama apresentou melhores resultados na presença de argila organofílica, sendo ainda melhores apenas na presença de sais quaternários de fosfônio. No sentido de melhorar as propriedades de flamabilidade do PBT sem perder em propriedades mecânicas, utilizou-se o agente tenacificante P(E-co-MA-co-GMA), copolímero etileno acrilato de metila metacrilato de glicidila. Desta forma, foram preservadas as propriedades mecânicas e retardância à chama.<br>In this work, nanocomposites of PBT, poly (butylene terephthalate) and Brazilian clay montmorillonite (MMT) organically modified were obtained with and without further addition of toughening agent. Quaternary ammonium and phosphonium salts with different chemical structures were used to organically modify the clays. PBT nanocomposites with commercial organoclays were also obtained for comparison. The materials were mixed using a mixer and a twin screw, coupled to a torque rheometer. The efficiency of cation exchange was evaluated by X-ray diffraction (XRD), swelling and thermogravimetric analysis (TGA). The dispersion of PBT with modified clay (OMMT) was evaluated by XRD, optical microscopy and transmission electron microscopy (TEM). The toughness dispersion was evaluated by scanning electron microscopy (SEM). The flammability and mechanical properties were also evaluated. Thermogravimetric analysis (TGA) of the OMMTs and PBT / OMMTs was also studied. The basal spacing obtained from XRD analysis were shown to depend on the architecture of the quaternary salt used and were larger for long alkyl chains. The quaternary salt excess was not removed during the washing step. The highest thermal stability was obtained with quaternary phosphonium salts. After adding the PBT, it was observed that the addition of organoclay to the polymer matrix did not contribute to a significant improvement of mechanical properties and in some cases even resulted in a decrease of mechanical properties. However, the flame retardancy showed best results in the presence of organoclay. The best results for the flammability properties were observed in the presence of only quaternary phosphonium salts. However, these materials were very fragile. In order to improve the flammability properties of PBT maintaining the mechanical properties, a toughening agent P(E-co-MA-co-GMA), copolymer ethylene methyl acrylate glycidyl methacrylate was used. In doing so both the mechanical and flame retardancy were preserved.
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Sartori, Mariana do Nascimento. "Estudo e desenvolvimento de nanocompósitos PBT/argila bentonita tratados por radiação ionizante - preparação e caracterização." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-28042015-145451/.
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Este trabalho apresenta a preparação e caracterização de compósitos baseados em poli (tereftalato de butileno) PBT e argila brasileira modificada preparados por intercalação por fusão. Os nanocompósitos de PBT com 3 e 5 %, em peso, de argila organicamente modificada, pela adição de um sal quaternário amônio, foram preparadas pelo processo de extrusão utilizando-se uma máquina extrusora dupla rosca. Após o processo de extrusão, os materiais foram injetados para obtenção de corpos-de-prova para os ensaios de caracterização. Parte dos corpos-de-prova foram submetidos ao processo de irradiação utilizando-se um acelerador de feixes de elétrons de 1,5 MeV, à temperatura ambiente e na presença de ar. As amostras de PBT puro e nanocompósitos irradiadas e não irradiadas foram caracterizadas por meio de ensaios mecânicos de tração, flexão e impacto, ensaios de temperatura de distorção térmica (HDT), difração de raios - X (DRX), microscopia eletrônica de varredura (MEV), índice de fluidez, termogravimetria (TG) e calorimetria exploratória diferencial (DSC) e a correlação entre as propriedades foi discutida. Os resultados mostraram que a adição da argila, em ambas as porcentagens, promoveu aumento superior a 50 % na resistência a tração na ruptura e um ganho de cerca de 35 % na temperatura de distorção térmica quando comparado ao polímero puro. O tratamento por radiação ionizante de feixe de elétrons nas doses utilizadas neste estudo não apresentaram mudanças significativas nas propriedades dos materiais.<br>This work describes the preparation and characterization of composites based on poly (butylene terephthalate) - PBT and brazilian modified clay prepared by the melt intercalation. PBT nanocomposites with 3 and 5 % by weight of organically modified clay, by the addition of a quaternary ammonium salt, were prepared by extrusion using a twin-screw extruder machine. After the extrusion process, the materials were injected to obtain specimens tests samples for the characterization tests. Part of the specimens samples were irradiated using an electron beam accelerator with 1.5 MeV at room temperature in the presence of air. Samples of pure PBT and irradiated and non-irradiated nanocomposites were characterized by mechanical tests of tensile, flexural and impact, heat distortion temperature (HDT), X - ray diffraction (XRD), scanning electron microscopy (SEM), melt flow index (MFI) thermogravimetry (TG) and differential scanning calorimetry (DSC) and the correlation between the properties was discussed. The results showed that the addition of clay, in both percentages, promoted an increase greater than 50 % in tensile strength at break and a gain of around 35% in heat distortion temperature when compared to the pure polymer. The treatment with ionizing radiation of electron beam at the doses used in this study showed no significant changes in material properties.
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Costa, Lidiane Cristina. "Desenvolvimento de blendas nanoestruturadas SAN/PBT modificadas com copolímeros acrílicos reativos." Universidade Federal de São Carlos, 2012. https://repositorio.ufscar.br/handle/ufscar/704.
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Previous issue date: 2012-08-02<br>Universidade Federal de Minas Gerais<br>In this work we have obtained transparent nanoblends of poly(styrene-coacrylonitrile) (SAN) as matrix and poly(butylene terephthalate) as a nanometric phase. The materials were produced by means of reactive mixing in a twin screw extrude. The development of compatibilization systems, in order to diminish the dimension of dispersed phase in situ, can be seen as a great scientific challenge in nanoblends field. In such case, the compatibilizer optimizes the comminution and prevents the coalescence process of the dispersed phase. The compatibilization between SAN and PBT phases was performed using terpolymers of methyl methacrylate (MMA), glycidyl methacrylate (GMA), and ethyl acrylate (EA), denoted as MGE. Using bulk polymerization, we have applied different conditions for compatibilizer syntheses, in order to achieve a decreasing in the MGE molecular weight. The analyses of the reactivity of different compatibilizer with PBT were accomplished by using both torque rheometry and transmission electron microscopy. We have noticed that as the molecular weight of MGE decreases, the particles sizes of the dispersed phase diminishes accordingly. This part of the study culminated in the selection of the better MGE for nanoblends production. Blends with concentration varying from 3 to 30% wt were prepared in an extruder. These nanoblends were characterized with respect to thermal, dynamic-mechanical, rheological, mophorlogical and optical properties. We have shown that the MGE incorporation presents a high-efficiency for the decreasing of the PBT domains and plays an important role for the optical properties of the resulting nanoblends.<br>Neste trabalho nanoblendas polimericas transparentes a base de poli(estirenoco- acrilonitrila) (SAN) como matriz e o poli(tereftalato de butileno) (PBT) como fase nanometrica foram obtidas. Esses materiais foram produzidos por meio de mistura reativa em uma extrusora dupla rosca. Um grande desafio cientifico e tecnologico para a area de nanoblendas e desenvolver sistemas de compatibilizacao in situ a fim de reduzir as dimensoes da fase dispersa na matriz polimerica. Neste caso, o compatibilizante exerce a acao de otimizar o processo de cominuicao da fase dispersa e prevenir a etapa de coalescencia. A compatibilizacao entre as fases SAN e PBT foi realizada atraves de terpolimeros (MGE) sintetizados a partir dos monomeros metacrilato de metila (MMA), metacrilato de glicidila (GMA) e acrilato de etila (EA). Por meio do metodo de polimerizacao em massa, diferentes condicoes de sintese para o compatibilizante foram aplicadas a fim de alcancar uma reducao da massa molar do MGE. A reatividade de diferentes compatibilizantes com o PBT foi avaliada principalmente atraves de reometria de torque e microscopia eletronica de transmissao. Observou-se uma diminuicao no tamanho de particulas da fase dispersa em funcao do decrescimo da massa molar do terpolimero. Esta etapa do estudo culminou na selecao do MGE com melhor desempenho e potencial para que nanoblendas fossem alcancadas durante o processo de extrusao reativa. Blendas com concentracoes de PBT variando entre 3 e 30% em massa foram preparadas em extrusora. Essas nanoblendas foram caracterizadas quanto as suas propriedades termicas, dinamicomecanicas, reologicas, morfologicas e opticas. A incorporacao de MGE apresentou grande eficiencia na diminuicao do tamanho da fase dispersa de PBT na matriz de SAN e desempenhou papel fundamental nas propriedades opticas das nanoblendas.
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Ravi, Sankar Ashwin. "Molecular weight effects of PBT-6 polymeric semiconductor on charge carrier mobility." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50414.
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Organic π-conjugated Donor-Acceptor copolymers are emerging as potential candidate materials for organic field effect transistor (OFET) and organic photovoltaic (OPV) applications. The electron-deficient benzothiadiazole group coupled with an electron-rich oligothiophene to form donor-acceptor copolymers has attracted significant attention. These low optical band gap materials absorb photons in the range of 400-800 nm and exhibit good thermal stability. In particular, poly(benzothiadiazole-sexithiophene) (PBT6) exhibits excellent performance in optoelectronic devices and high thermal stability. Here, we present the chemical synthesis and characterization of the polymer, PBT6. Three samples of PBT-6 with differing molecular weights in the range of Mn 18000-45000 Da were synthesized. Each polymer was characterized with respect to its photophysical, thermal properties and field-effected mobility was determined. Devices were prepared by drop-casting polymer solutions in 1,2-dichlorobenzene (DCB) onto an OFET (bottom gate/bottom contact) substrate and the devices were used to examine the charge transport properties of each polymer system. The optimal solvent to be used for processing technique was determined and surface techniques using OTS-8 and OTS-18 were compared through contact angle measurements. The measured charge carrier mobilities were in the range of 0.45-0.6 cm² / V.s. Polymer films prepared via drop-casting and which were thermal annealed exhibit mobilities as high as 0.825 cm² / V.s. This work examines the effect of molecular weight on the charge carrier transport properties and demonstrates the correlation of performance with molecular ordering. Drop-casted films of PBT-6 exhibit highly ordered crystalline lamellar structure with high degree of π- π stacking with edge-on orientation on the substrate. The longer conjugation lengths promote intrachain charge transfer. This high degree of molecular ordering in high MW samples of PBT6 improves the interchain and intrachain charge transfer leading to enhanced mobilities. The increased molecular weight (MW) facilitates in forming more uniform thin films which is vital in processing and application of polymer thin film technologies. These results and observations clearly demonstrate the potential of PBT-6 as a semiconducting material for Optoelectronic devices.
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Dos, Santos JoseÌ Manuel Ribeiro Correia Afonso. "Phase separation and phase preferences in pigmented, impact-modified, PC/PBT blends." Thesis, University of Leeds, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400266.
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Figueira, Rossana Cristina Rossoni. "Análise da processabilidade de blendas PBT/ABS compatibilizadas in situ com copolímeros acrílicos." Universidade Federal de São Carlos, 2007. https://repositorio.ufscar.br/handle/ufscar/683.
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Previous issue date: 2007-12-14<br>Universidade Federal de Sao Carlos<br>Poly(butylene terephthalate)/acrylonitrile-butadiene-styrene (PBT/ABS) blends show high toughness at room temperature, low ductile-brittle transition temperature and stable morphology when compatibilized. The flowability of PBT/ABS blends compatibilized in situ with methyl metacrylate- glicydil metacrylate-etyl acrylate (MGE) copolymer changes drastically with the kinds of ABS, PBT used and with the level of interfacial adhesion. In this work, a high rubber content ABS was mixed with PMMA and SAN copolymer. These blends were introduced in PBT/ABS/MGE system to study the processability. The addition of ABS/SAN or ABS/PMMA in the PBT/ABS/MGE blends didn t show high decreased of the torque in the blends with rubber content of 12 and 16 wt%. PBT 315/ABS/MGE and PBT 325/ABS/MGE blends showed inversion of viscosity concerning pure ABS under permanent shear condition. The mechanical properties of PBT/(ABS/SAN or PMMA)/MGE showed that the Young modulus and yield stress are not affected by the change of PBT matrix molecular weight. The kind of PBT matrix used changes strongly the blends behavior under impact, altering the values of ductile-brittle transition temperature and impact resistance. PBT 315 and ABS showed almost the same flow length. The compositions with ABS/PMMA added showed a higher flow length tendency in PBT 315 and PBT 325 blends. Blends with PBT 195 showed better flowability. However, these blends didn t become tough systems. The better mechanical properties/moldability relationship to PBT 315 and PBT 325 blends was observed for ABS/SAN or ABS/PMMA added with a rubber content of 30 %wt.<br>Blendas poli(tereftalato de butileno)/acrilonitrila-butadieno-estireno (PBT/ABS) apresentam alta tenacidade à temperatura ambiente, baixa temperatura de transição frágil-dúctil e morfologia estável quando compatibilizadas. O comportamento no estado fundido de sistemas PBT/ABS compatibilizados in situ com o copolímero metacrilado de metila-metacrilato de glicidila-acrilato de etila (MGE) sofre forte influência dos tipos de ABS e PBT utilizados, bem como do grau de adesão interfacial gerado pelo compatibilizante. Neste trabalho, um ABS com elevado conteúdo de fase borrachosa foi diluído com copolímero SAN e PMMA. Estas blendas foram introduzidas no sistema PBT/ABS/MGE para estudo da sua processabilidade. A adição de ABS/SAN ou ABS/PMMA nas blendas PBT/ABS/MGE não apresentou acentuada diminuição do torque tanto nas blendas com proporção mássica de fase borrachosa igual a 12 % como naquelas com 16% em massa. Sob regime permanente de cisalhamento, as blendas PBT 315/ABS/MGE e PBT 325/ABS/MGE apresentam inversão da viscosidade em relação ao ABS puro. As propriedades mecânicas das blendas PBT/[(ABS/SAN ou PMMA)]/MGE mostraram que o módulo de Young e a tensão no escoamento são relativamente insensíveis à alteração da massa molar da matriz PBT numa dada composição. O tipo de matriz PBT utilizada influencia fortemente o comportamento sob impacto das blendas, alterando tanto os valores da temperatura de transição frágil-dúctil como a resistência ao impacto para uma dada temperatura. O PBT 315 e o ABS apresentaram praticamente o mesmo comprimento de fluxo. As composições em que se adicionou ABS/PMMA apresentaram uma tendência a maior comprimento de fluxo tanto nos sistemas com PBT 315 como naqueles com PBT 325. As blendas com PBT 195 apresentam maior habilidade em preencher o molde. Entretanto, estas blendas não resultaram em sistemas tenazes. A melhor correlação propriedades mecânicas/moldabilidade para blendas com PBT 315 e 325 foi para os sistemas onde adicionou-se ABS/SAN ou ABS/PMMA com 30 % em massa de fase borrachosa.
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Elliott, Simon J. "The influence of fire retardant additives on the properties of HIPS and PBT." Thesis, Loughborough University, 2002. https://dspace.lboro.ac.uk/2134/36002.
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Halogen compounds and antimony-based synergists are used at low loading levels in many polymers systems to impart high levels of flame retardancy. This study used a range of brominated flame retardants (BFR) and the most commonly used synergist for halogen-based flame retardance, antimony trioxide (Sb2O3), to investigate the effects on mechanical and physical properties of flame retardants in HIPS and PBT. The polymers used were High Impact Polystyrene (HIPS) and Polybutylene Terephthalate (PBT). Initially each of the additives was used individually, before being combined to study the effect of the complete package. This was achieved by producing a series of compounds using a twin-screw extruder, and then an injection moulder to produce impact, tensile and fracture toughness specimens. The compounds were also analysed using rheological testing and thermal analysis. Also the effects of Stereon impact modifier and Fyrebloc masterbatches were determined in HIPS.
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Morel, Patrick. "Mécanismes de photo-oxydation de mélanges physiques PBT/PC - PPO/PA - PA/PP." Clermont-Ferrand 2, 1990. http://www.theses.fr/1990CLF21309.
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Les techniques expérimentales d'étude du comportement a long terme des matériaux polymères à partir de mesures réalisées en photovieillissement accéléré et en thermo-oxydation ont pu être exploitées pour des systèmes aussi complexes que des mélanges physiques. Dans de tels mélanges, les conjugaisons qui interviennent entre macro- et microphases ont été examinées. Dans le cas des mélanges PBT/C, la macrophase PBT/PC se comporte essentiellement comme un PBT pur alors que les microphases élastomères induisent une hydroperoxydation importante du PBT et de l'interphase entre nodules d'élastomères et la macrophase. Le système PPO/PA/élastomère diénique est le siège d'une photo-oxydation rapide et localisée dans les couches les plus superficielles. Le ppo est intrinsèquement le site le plus photo-oxydable du mélange ppo/pa et l'essentiel des photoproduits observes sont en fait des produits de photo-oxydation et de photolyse du PPO. Enfin, le mélange PA/PO est un exemple ou les deux constituants présentent des photo-oxydations conjuguées se traduisant par une formation plus rapide de photoproduits issus de la matrice polypropylène, les périodes d'induction généralement observées dans les polypropylènes homopolymères étant pratiquement éliminées dans les mélanges.
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Wu, Jingshen. "Fracture toughness and toughening mechanisms of poly(butylene terephthalate)/polycarbonate (PBT/PC) blends." Thesis, The University of Sydney, 1994. https://hdl.handle.net/2123/26705.
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Poly(buty1ene terephthalate)/polycarbonate (PBT/PC) system was selected in the present study on the fracture toughness and toughening mechanisms of rigid-rigid polymer blends. A comprehensive review on the toughening mechanisms for traditional rubber toughened and rigid polymer toughened polymer blends was given. Techniques for fracture toughness characterisation and toughening mechanism analysis were introduced and compared. The equivalence of the critical J—integral and the specific essential work of fracture was proven experimentally. There is no geometry dependence of the specific essential work of fracture as verified with three different specimens, namely, Single-Edge-Notched Three-Point-Bend (SEN—3PB), Compact Tension (CT) and Double-Edge-Notched-Tension (DENT). The specific essential work of fracture concept has been successfully extended to impact testing and the kinetic energy effect is discussed.
A relatively thorough investigation on the morphology, mechanical properties, fracture toughness and toughening mechanisms was first conducted on a commercial grade PBT/PC/impact modifier (IM) blend under different testing conditions. Toughening mechanisms and sequence of toughening events were studied by SEM and TEM. It is suggested that the expansion of IM particles and matrix crazing under triaxial stress takes place first, which is followed by the cavitation inside of the IM particles and/or at the boundary between IM particle and matrix. Further expansion of the cavities reduces the thickness of the ligaments between them and eventually relieves the plane—strain constraint allowing massive shear deformation in the matrix to occur. It is believed that this matrix shear deformation provides the major contribution in toughening this commercial blend.
To be able to modify the microstructures and hence to study the structure-property relationship a series of PBT/PC blends with and without IM particles were subsequently fabricated using a twin screw extruder with different processing control successfully. It was found that the morphology of the blends changed gradually with the percentage of PET from PC-matrix/PBT-particle to PC-particle/PBT-matrix. Bi-continuous structure was observed with the PBT/PC (40/60) and (50/50) blends. A relatively strong boundary between PET and PC domains was found in the PC—rich blends which could be tentatively attributed to the PBT/PC copolymer generated by transesterification during processing.
In the toughened PBT/PC blends without IM, new toughening mechanisms are first observed. These include: (1) crazes formation in matrix under triaxial stress state, (2) crazes stabilisation by PC domains which prevent the crazes from developing into harmful cracks, (3) debonding—cavitation at the interface between PET and PC when the triaxial stress reaches its debonding strength, (4) relief of plane—strain constraint via debonding-cavitation which promotes massive shear yielding in matrix and (5) crack bridging by PC domains which is suggested as a possible major toughening mechanism. It is significant that in these blends the PC domains not only stabilise the growing crazes but also bridge the crack surfaces, enlarge the plastic zone size and result in a high fracture toughness. To enable these toughening mechanisms an appropriate bond strength between PET and PC is critical. It should be strong enough to provide the crack-bridging effect but not too strong to prevent debonding—cavitation to occur.
The effects of processing condition, testing temperature, strain rate and IM addition on the fracture behaviour of the laboratory prepared PBT/PC blends were also studied. Mechanisms responsible in toughening PBT/PC blends at impact loading rate were proposed; and possible correlations between fracture toughness and molecular relaxation processes were discussed. The optimum volume fraction of IM particle in this PBT/PC/IM system was found and the role of the IM in toughening was investigated using OM and SEM.
Based on the results of the present study, some suggestions on future work in this area and on the design of tough rigid—rigid polymer blends are given.
Books on the topic "PBT"
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Pergola, Federico. Fraudes y mistificaciones en publicaciones argentinas del siglo XX: Información riesgosa para la salud : violación de las leyes e ineficacia en los controles. Librería Akadia Editorial, 2011.
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TOEFL secrets (CBT & PBT versions) study guide: Your key to exam success : TOEFL review for the Test of English as a Foreign Language (computer-based test & paper-based test). Mometrix Media LLC, 2011.
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Saloniemi, Heini. Electrodeposition of PbS, PbSe and PbTe thin films. Technical Research Centre of Finland, 2000.
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Kim, E. Edmund, Myung-Chul Lee, Tomio Inoue, and Wai-Hoi Wong, eds. Clinical PET and PET/CT. Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4419-0802-5.
Full textBook chapters on the topic "PBT"
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Bashford, David. "Polybutylene Terephthalates (PBT)." In Thermoplastics. Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-009-1531-2_66.
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Rofé, Yacov. "Repression: The Cornerstone of PBT." In The Rationality of Psychological Disorders. Springer US, 2000. http://dx.doi.org/10.1007/978-1-4615-4333-6_4.
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Sijm, D. T. H. M. "The 'B' in PBT: Bioaccumulation." In ACS Symposium Series. American Chemical Society, 2000. http://dx.doi.org/10.1021/bk-2001-0772.ch002.
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Gooch, Jan W. "Styrene Maleic Anhydride Copolymer PBT Alloy." In Encyclopedic Dictionary of Polymers. Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_11346.
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Sartori, Mariana N., Rene R. Oliveira, Francisco R. V. Diaz, Angel Visentim Ortiz, Vijaya K. Rangari, and Esperidiana A. B. Moura. "Preparation and Characterization of PBT/Clay Nanocomposite." In T.T. Chen Honorary Symposium on Hydrometallurgy, Electrometallurgy and Materials Characterization. John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118364833.ch68.
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Rofé, Yacov. "PBT as a Unified Theory of Psychotherapy." In The Rationality of Psychological Disorders. Springer US, 2000. http://dx.doi.org/10.1007/978-1-4615-4333-6_7.
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Molnár, Tamás, and Gyula Dura. "Environmental Effect Assessment of Organic PBT Compounds." In Exposure and Risk Assessment of Chemical Pollution — Contemporary Methodology. Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-90-481-2335-3_19.
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Pardasani, R. T., and P. Pardasani. "Effective magnetic moment of [Mn(pbt)2Br2]." In Magnetic Properties of Paramagnetic Compounds. Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-23675-4_927.
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Pardasani, R. T., and P. Pardasani. "Effective magnetic moment of [Mn(pbt)2I2]." In Magnetic Properties of Paramagnetic Compounds. Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-23675-4_928.
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Pardasani, R. T., and P. Pardasani. "Effective magnetic moment of [Mn(pbt)Br2]." In Magnetic Properties of Paramagnetic Compounds. Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-23675-4_926.
Full textConference papers on the topic "PBT"
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Sancaktar, E., N. Negandhi, and S. Adwani. "Evaluation of Processing Effects in Injection Molded Thermoplastics Using Excimer Laser." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-59356.
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The ablation behavior of amorphous (polystyrene (PS), and polycarbonate (PC)) and crystalline (poly(ethylene terephthalate) (PET), and glass filled poly(butylenes terephthalate) (PBT)) polymers by 248 nm KrF excimer laser irradiation were investigated for different injection molding conditions namely, injection flow rate, injection pressure, and mold temperature, as a possible method to evaluate the processing effects in the specimens. For this purpose, dumb-bell shaped samples were injection molded at different sets of processing conditions, and weight loss measurements were carried out for the different injection molding conditions. Some of the crystalline (PET) samples were annealed at different annealing time and temperature. For PET, weight loss decreased with increasing mold temperature and remained insensitive to injection flow rate. Annealing time and temperature significantly reduced weight loss in PET. For PBT, the weight loss due to laser ablation reduced with increase in material packing due to pressure, and also showed some sensitivity to flow rate variation. The major effect was seen with glass filled PBT samples. The weight loss decreased drastically with increasing glass fiber content. Laser ablation allowed observation of process induced fiber orientation by SEM in PBT samples. For PS and PC, the weight loss increased with increases in the injection flow rate and mold temperature, and decreased with increasing injection pressure. Position near the gate showed higher ablation than the position at the end for all the conditions. A decrease in the material orientation, with injection speed and mold temperature, led to increase in the weight loss, while increase in the injection pressure, and consequently orientation, led to lower weight loss for PS and PC. Higher residual stress samples showed higher weight loss.
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Lu, Xiang, and Jinping Qu. "Morphology and properties of PBT/SEBS and PBT/SEBS-G-MAH blends." In PROCEEDINGS OF PPS-31: The 31st International Conference of the Polymer Processing Society – Conference Papers. AIP Publishing LLC, 2016. http://dx.doi.org/10.1063/1.4942280.
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La Carrubba, V., S. Piccarolo, and V. Brucato. "Analysis of the crystallization behaviour of PBT-rich PBT/PET blends under processing conditions." In 10TH ESAFORM CONFERENCE ON MATERIAL FORMING. AIP, 2007. http://dx.doi.org/10.1063/1.2729609.
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Bottjer-Wilson, Daniela, and Barbara C. Bruno. "Place Matters! Fostering place-based geoscience teaching at the University of Hawai‘i at Mānoa." In Fifth International Conference on Higher Education Advances. Universitat Politècnica València, 2019. http://dx.doi.org/10.4995/head19.2019.9237.
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Drawing on the importance of place has been shown to be a powerful tool in education. This paper explores place-based teaching (PBT) in geoscience courses at the University of Hawai‘i at Mānoa’s School of Ocean and Earth Science and Technology, where faculty and student demographics sharply differ. Despite these differences, survey results from geoscience faculty (n=59) and students (n=83) revealed a strong consensus: 78% of students and 83% of faculty reported that PBT is an important and effective practice to reach all students. Most faculty (91%) indicated that they currently incorporate at least some PBT practices in their geoscience classes and would like to incorporate additional ones in the future. However, many faculty expressed concern about lack of knowledge or resources, particularly regarding PBT strategies that require a high level of cultural competency. We therefore propose a three-layered PBT framework, where faculty can start with more accessible PBT strategies (the base layer) and progress upwards as their cultural competency deepens. Through providing geoscience resources and professional development opportunities, we can empower faculty to include more diverse and culturally meaningful practices as their experience and knowledge deepens.
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Mago, Gaurav, Jerry A. Dutreuil, Frank T. Fisher, and Dilhan M. Kalyon. "Effect of Uniaxial Deformation, Annealing and Carbon Nanotubes on the Morphology and Mechanical Properties of Poly (Butylene Terephthalate) and PBT Nanocomposites." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-41977.
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The goal of this investigation is to elucidate the interrelations between the strain-induced crystallization behavior, morphology and mechanical properties of poly (butylene terephthalate) PBT and its nanocomposites with multi-walled carbon nanotubes (MWNTs). The mechanical properties of semicrystalline polymers such as PBT depend upon the processing conditions, which affect the crystallization behavior and the resulting crystal morphology developed within the processed sample. PBT is observed to undergo strain-induced crystallization during uniaxial deformation, with concomitant changes in the polymer crystal as a function of the applied strain history. In the current work polymer morphology was investigated with wide angle XRD, differential scanning calorimetry (DSC) and polarized light microscopy (PLM). DSC results indicate an increase in crystallinity due to strain-induced crystallization during uniaxial cold-stretching, which was further confirmed with XRD analysis of the samples. Analyses of the samples under polarized light pre- and post-stretching clearly show that there is a transformation of the spherulitic crystals of the pre-stretch morphology into elongated oblong crystals, as the imposed strain exceeds a critical value. Annealing of PBT was done under different conditions to probe the effects of changes in the crystallinity obtained upon thermal treatment on polymer morphology and mechanical properties. The annealed samples were found to have high crystallinity, high Young’s modulus, and low yield stress values as compared to unannealed samples processed under similar conditions. To investigate the effects of nanoparticle loadings on PBT crystal morphology and mechanical properties, pure PBT was melt mixed with different concentrations of multi-walled carbon nanotubes (MWNTs). Due to the increased nucleation rate effect associated with the incorporation of MWNTs, the PBT crystallization temperature was increased and the crystal size decreased with the increasing concentration of MWNTs. Tensile tests performed on PBT and their nanocomposite samples revealed decreases in the elongation at break values. Research is ongoing to understand the relationship between the MWNT loading levels and mechanical properties along with study of orientation of MWNTs under tensile load and its effect on strain-induced crystallization.
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Sanchez, Elisabete Maria Saraiva. "Ageing of PC/PBT Blend: Mechanical Properties." In SAE Brasil 2005 Congress and Exhibit. SAE International, 2005. http://dx.doi.org/10.4271/2005-01-4044.
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Takashima, Yoshiki. "PropProof: Free Model-Checking Harnesses from PBT." In ESEC/FSE '23: 31st ACM Joint European Software Engineering Conference and Symposium on the Foundations of Software Engineering. ACM, 2023. http://dx.doi.org/10.1145/3611643.3613863.
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Kato, Kazuo, Takashi Aoki, Yasushi Okamoto, Keiji Tanaka, and Atsushi Takahara. "Reliability Analysis of Adhesive for PBT-Epoxy Interface." In SAE World Congress & Exhibition. SAE International, 2007. http://dx.doi.org/10.4271/2007-01-1517.
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Lin, Zhijie, Chonghui Ren, Haifeng Huang, and Xiaoyong Li. "Dynamic Load Balancing Method Based on PBT Tree." In 2017 2nd International Conference on Electrical, Control and Automation Engineering (ECAE 2017). Atlantis Press, 2018. http://dx.doi.org/10.2991/ecae-17.2018.63.
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Wang, Liming, Tatsuo Wada, Tomoyuki Yuba, Masaaki Kakimoto, Yoshio Imai, and Hiroyuki Sasabe. "Nonlinear Optical Anisotropy of Highly Oriented Poly(p-Phenylene Benzobisthiazole)Langmuir-Blodgett Films." In Organic Thin Films for Photonic Applications. Optica Publishing Group, 1995. http://dx.doi.org/10.1364/otfa.1995.md.26.
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Poly(p-phenylene benzobisthiazole) (PBT) has received a strong attention as a nonlinear optical (NLO) material because of its large, ultrafast NLO response1 and inherently superior physical and chemical properties2. However, the material is difficult to process into thin film with good optical quality, which hindered the detailed and accurate NLO studies. In order to improve optical quality, the PBT Langmuir-Blodgett (LB) films were fabricated via a novel precursor route. The PBT LB films show not only improved optical quality but also highly in-plane oriented molecular packing. Because the π-electrons are delocalized along the polymer chain direction, the highly oriented packing of the polymer chains results in linear and NLO anisotropy properties. Therefore, in-plane anisotropy measurement of optical third-harmonic generation (THG) is one of the powerful tools to elucidate the packing arrangement in LB films of one-dimensional conjugated system.
Reports on the topic "PBT"
1
Harruna, Issifu I., and Malcolm B. Polk. Molecular Control of Liquid Crystalline Orientation of PBO and PBT. Defense Technical Information Center, 1992. http://dx.doi.org/10.21236/ada251214.
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Moxham-Hall, Vivienne, Anton du Toit, Sallie Newell, Stuart Brentnall, Deshanie Rawlings, and Eileen Goldberg. Proton beam therapy: A rapid review of the evidence since 2020. The Sax Institute, 2023. http://dx.doi.org/10.57022/tjvf1783.
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The purpose of the report is to conduct a rapid review of the recent evidence (since 2020) on proton beam therapy (PBT) for: paediatric cancers, central nervous system (CNS) tumours, head and neck cancer and prostate cancer. The report aims to provide a rapid summary of the current knowledge about PBT’s effectiveness, safety, and potential advantages over conventional radiation therapy. The report includes evidence that has become available subsequent to the evidence submitted in the South Australian Health and Medical Research Institute (SAHMRI)’s Medical Services Advisory Committee (MSAC) application requesting Medicare Benefits Schedule (MBS) listing of PBT for paediatric and rare cancers (MSAC Application No. 1638). In addition, the report presents data on international benchmarking of PBT facilities per million population, and with consideration to Australia’s population and numbers of people with cancers recommended for public funding for PBT by MSAC.
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Mallon, P. J., M. A. Dweib, S. Ziaee, A. Chatterjee, and J. W. Gillespie. VARTM & RTM Processing of PBT & PA Thermoplastic Composites. Defense Technical Information Center, 2002. http://dx.doi.org/10.21236/ada408706.
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Marks, Tobin J., and Stephen H. Carr. PBT (Poly(p-phenylenebenzobisthiazole)) PBO (Poly(p-phenylenebenzobisoxazole))-Based Hybrid Polymers with Nonlinear Optical Properties or High Electrical Conductivity. Defense Technical Information Center, 1986. http://dx.doi.org/10.21236/ada177213.
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Moxham-Hall, Vivienne, Anton du Toit, Sallie Newell, Stuart Brentnall, Deshanie Rawlings, and Eileen Goldberg. Proton beam therapy: a rapid review of the evidence since 2020. The Sax Institute, 2023. http://dx.doi.org/10.57022/nbys4168.
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This report for Cancer Australia is a rapid review of the evidence since 2020 on proton beam therapy (PBT) for paediatric cancers, central nervous system (CNS) tumours, head and neck cancer and prostate cancer. The report aims to provide a rapid summary of the current knowledge about PBT’s effectiveness, safety, and potential advantages over conventional radiation therapy. We identified the following papers for full review: 24 peer reviewed papers, including 4 meta-analyses, 16 systematic reviews, 3 narrative reviews, and 1 randomised controlled trial (RCT); and 2 publicly available health technology assessments (HTAs) in the grey literature. The overall quality of evidence in these reviews was limited due to factors such as small sample sizes, non-randomised study designs, heterogeneity in study designs, and short follow-up periods. Many reviews noted that there is a need for well-designed randomised and model-based clinical trials to provide a stronger evidence base for PBT for particular cancer types. Note that this rapid review was completed within a three-week timeframe so while searches were performed systematically, it is possible that some literature may have been missed. Overall, there is a need for more high-quality evidence to better understand the effectiveness, safety, and cost-effectiveness of PBT in various cancer types and populations.
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Horton, Michael J. Software Technology for Adaptable, Reliable Systems (STARS). User Manual. PCTE Browser Tool (PBT) Version 1.0. SunOs Implementation. Defense Technical Information Center, 1992. http://dx.doi.org/10.21236/ada285086.
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Horton, Michael J. User Manual for the Software Technology for Adaptable, Reliable Systems (STARS). PCTE Browser Tool (PBT) Version 0.1 SunOS Implementation. Defense Technical Information Center, 1992. http://dx.doi.org/10.21236/ada257064.
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Potrepka, Daniel M., Glen R. Fox, and Ronald G. Polcawich. Optimization of PZT Thin Film Crystalline Orientation Through Optimization of TiO2/Pt Templates. Defense Technical Information Center, 2011. http://dx.doi.org/10.21236/ada536343.
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Petrik, W. A., and R. D. Reger. Hydrologic and geologic conditions and hazards at the put 23 pit site, Beechey Point B-3 SW Quadrangle, Alaska. Alaska Division of Geological & Geophysical Surveys, 1990. http://dx.doi.org/10.14509/1469.
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Hasbrouck, J. Geophysical surveys at INEL/RWMC Cold Pit, Acid Pit, and Pit 9. Office of Scientific and Technical Information (OSTI), 1989. http://dx.doi.org/10.2172/5330916.
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