1,466 research outputs found

    Seeded emulsion polymerization of vinyl acetate

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    The study of seeded emulsion polymerization of vinyl acetate in the absence of emulsifiers, with potassium persulfate as an initiator has been conducted in order to investigate the kinetics and mechanism of particle nucleation. Poly(vinyl acetate) latex particles are stabilized by the ionic end groups from decomposition of initiator. The polymerization behaviour of vinyl acetate in the water phase has been clarified. The variation of the polymerization rate with changes in initiator concentration, monomer-polymer ratio, and stirring speed were determined. The polymerization rate of seeded emulsion polymerization of vinyl acetate is dependent on the initiator concentration to the 0.60 ¬Ī 0.05 power, however, it is independent of the monomer-polymer ratio. There was no significant change in polymerization rate when the stirring rate was changed from 50 to 150 rpm, but, the polymerization rate was considerably reduced when the stirring rate was increased to 300 rpm. New small particles were formed in the system where the monomer-polymer ratio was substantial large (that is the system containing a small amount of seed particles). The emulsifier-free emulsion polymerization of vinyl acetate in the absence of seed particles was also investigated. It was found that the polymerization rate is proportional to the 0.69 power of initial monomer concentration

    Test of Perfomance ERK Hybrid Dryer with Biomass Furnace as Additional Heating System for Nutmeg Seed (Myristica SP.) Drying

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    Conventional drying depend on the weather. It was caused agricultural product damaged, and moldy attack. So we need hybrid dryer with a source of radiation and solar biomass to continuous drying and can be controlled.The aims of this research is test performance of ERK hybrid dryer to drying the nutmeg seed during the drying process. Experiments were conducted to determine the distribution of temperature in the dryer in condition with no material and material conditions. Input of energy derived from biomass combustion in the furnace (evening) and combination of biomass and radiation (during the day). Measurements of temperature and RH using a thermocouple CC and alcohol thermometer. Temperature and RH to be measured include temperature and RH in dryer with several measurement points representing the up, middle , bottom and inlet temperature, outlet temperature and ambient temperature measurements at intervals of 30 minutes. The results showed average temperature ranges between 42 ¬į C - 51 ¬į C and RH ranged between 50.96 % -55.65 % . Time of drying is used to dry nutmeg from the initial moisture content from 80.72 % wb to 9.67 % wb is 52 hours with an average drying rate is 7.8 % db / hour . The total energy used to heat and vaporize materials,water that is 290 499.9 kJ. Efficiency of drying system 8.63% and energy of drying required to water evaporated is 28520.62 kJ / kg. The result quality of product obtained color of nutmeg generally more uniform

    Standard Model Higgs Searches at the LHC

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    An overview of the searches for the Standard Model Higgs boson at the LHC is presented. The main Higgs production and decay modes that have been studied are introduced, and the analysis techniques and the recent developments done by the ATLAS and CMS experiments are described. Some preliminary results from current studies are included. The discovery potential within the first few years of physics running is evaluated

    A makro-TSH diagnosztikus √©s ter√°pi√°s jelentŇĎs√©ge Hashimoto-thyreoiditises betegekben | Diagnostic and therapeutical significance of macro-TSH in patients with Hashimoto‚Äôs thyroiditis

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    Absztrakt: Bevezet√©s: A makro-TSH szerkezete, incidenci√°ja √©s klinikai szerepe pajzsmirigybetegekben nem tiszt√°zott. C√©lkitŇĪz√©s: A makro-TSH elŇĎfordul√°si gyakoris√°g√°nak, tulajdons√°gainak meghat√°roz√°sa Hashimoto-thyreoiditises betegek sav√≥j√°ban. M√≥dszer: A Hashimoto-thyreoiditises betegek v√©rmint√°iban a makro-TSH-t meghat√°rozt√°k polietil√©n-glikol precipit√°ci√≥s m√≥dszerrel √©s protein G agar√≥z abszorpci√≥s, illetve g√©lfiltr√°ci√≥s kromatogr√°fi√°val. A makro-TSH biol√≥giai aktivit√°s√°t TSH-receptorral transzfekt√°lt CHO bioassay m√≥dszer√©vel m√©rt√©k. A betegek L-tiroxin-kezel√©sben r√©szes√ľltek (√°tlagosan 66,5 ¬Ķg/nap), a betegek fele pedig szel√©nt is kapott (√°tlagosan 60 ¬Ķg/nap). Eredm√©nyek: 880 Hashimoto-thyreoiditises beteget (728 nŇĎ, √°tlag√©letkor 44,8 √©v) vontak be a vizsg√°latba. A makro-TSH-t 41 betegben (4,6%) mutatt√°k ki, az √°tlagos TSH-szint a PEG-precipit√°ci√≥ elŇĎtt 185,4 ¬Ī 35 IU/l volt, a precipit√°ci√≥ ut√°n pedig 5,55 ¬Ī 1,8 IU/l. Az anti-TPO-szint 445 ¬Ī 51 IU/l volt √©s fokozatosan cs√∂kkent 212 ¬Ī 51 IU/l-re egy√©ves tiroxin- √©s szel√©nkezel√©s ut√°n. Mind a PEG-precipit√°ci√≥s, mind a protein G abszorpci√≥s m√≥dszerrel, illetve g√©lkromatogr√°fi√°s elj√°r√°ssal a TSH elleni antitest jelenl√©t√©t mutatt√°k ki a makro-TSH-immunkomplexben. A makro-TSH biol√≥gialag inakt√≠vnak bizonyult, mivel a CHO-sejteket nem stimul√°lta. A makro-TSH a szel√©nnel nem kezelt csoportban 18 ¬Ī 3,2 h√≥napig, a szel√©nnel kezeltben 12 ¬Ī 1,9 h√≥napig volt kimutathat√≥. K√∂vetkeztet√©s: A TSH elleni antitestek fŇĎ komponensei a makro-TSH-nak √©s diagnosztikus, illetve ter√°pi√°s neh√©zs√©geket okozhatnak. A PEG-precipit√°ci√≥s elj√°r√°s alkalmas szŇĪrŇĎm√≥dszer a makro-TSH bizony√≠t√°s√°ra. A szel√©n k√©pes nemcsak az anti-TPO-, hanem a makro-TSH-szint cs√∂kkent√©s√©re egyar√°nt. Amikor a TSH-szint 40,0 IU/l feletti a hypothyreosis jelei n√©lk√ľl, gondolnunk kell a makro-TSH jelenl√©t√©re. Orv Hetil. 2017; 158(34): 1346‚Äď1350. | Abstract: Introduction: Structure, importance and incidence and clinical role of macro-TSH not clarified in thyroid diseases. Aim: This study was undertaken to determine the incidence and biological role of macro-TSH in patients with Hashimoto‚Äôs thyroiditis. Method: Blood samples taken from patients with Hashimoto‚Äôs thyroiditis were screened for the presence of macro-TSH with the polyethylene glycol method and confirmed with protein G agarose absorption test and gel filtration chromatography. Stimulatory capacity of macro-TSH was measured by CHO cells bio-assay. Patients were treated with L-thyroxine (mean 66.5 ¬Ķg/day) and half of them with selenium (mean 60 ¬Ķg/day), respectively. Results: 880 patients (728 female, aged 44.8 yr) with Hashimoto‚Äôs thyroiditis was involved in the study. Macro-TSH was found in the serum of 41 patients (4.6%), the mean TSH 185.4 ¬Ī 35 IU/l was before PEG precipitations and after 5.55 ¬Ī 1.8 IU/l. Titre of anti-TPO proved to be 445 ¬Ī 51 IU/l and gradulally decreased to 212 ¬Ī 51 IU/l after one year therapy. Both the precipitation, protein G absorption and gel chromatography supported the presence of anti-TSH antibody in the macro-TSH complex. Stimulatory capacity of macro-TSH on CHO bio-assay was not proved. The macro-TSH was detected in the selenium not treated group for 18 ¬Ī 3.2 months, selenium-treated for 12 ¬Ī 1.9 months. Conclusion: It is concluded that anti-human TSH autoantibodies are a major components of macro-TSH and may cause diagnostic and therapeutical difficulties. The PEG precipitation is a suitable screening method for detection of macro-TSH. Selenium is able to decrease of anti-TPO antibodies and macro-TSH, respectively. When the TSH level is greater than 40.0 IU/l, without the signs of hypothyroidism, the presence of macro-TSH is to be considered. Orv Hetil. 2017; 158(34): 1346‚Äď1350

    Implementation and Reconfiguration of Robot Operating System on Human Follower Transporter Robot

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    Robotic Operation System (ROS) is an im- portant platform to develop robot applications. One area of applications is for development of a Human Follower Transporter Robot (HFTR), which can be considered as a custom mobile robot utilizing differential driver steering method and equipped with Kinect sensor. This study discusses the development of the robot navigation system by implementing Simultaneous Localization and Mapping (SLAM)

    Práticas de literacia familiar em benguela (angola): Um estudo exploratório.

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    As investiga√ß√Ķes mostram que a aprendizagem da linguagem escrita come√ßa muito antes do ensino formal e que as pr√°ticas e o ambiente de literacia familiar influenciam a literacia emergente e o desenvolvimento da linguagem escrita. Mas, se estes estudos s√£o desenvolvidos no Ocidente, em √Āfrica pouco se tem feito e em Angola n√£o se conhece nenhum estudo. Com base nos estudos existentes, em diversos contextos culturais, verifica-se que a literacia familiar existe, podendo as pr√°ticas variar no tipo e frequ√™ncia uma vez que o que se passa num contexto, pode n√£o ser igual ao que se passa noutra realidade cultural diferente. Neste sentido este trabalho, procura caraterizar as pr√°ticas e o ambiente familiar de literacia em 11 fam√≠lias de Benguela com um filho a frequentar o in√≠cio da escolaridade. Os dados foram recolhidos atrav√©s de uma entrevista informal aos pais. Os resultados mostram que as pr√°ticas de literacia familiar s√£o essencialmente pr√°ticas formais, muito ligadas √† escola e √†s tarefas escolares. No mesmo sentido verific√°mos que a responsabilidade pela aprendizagem da linguagem escrita √© atribu√≠da √† escola, e a explicadores. Apesar de surgirem algumas refer√™ncias do uso da literacia associado a pr√°ticas religiosas, poucas refer√™ncias foram feitas a pr√°ticas informais ou l√ļdicas. Foi clara a quase inexist√™ncia de materiais de leitura (jornais, livros, revistas) para al√©m dos escolares. A falta de tempo, a escassez de bibliotecas p√ļblicas e livrarias, a falta dos recursos financeiras para aquisi√ß√£o do material de literacia e a iliteracia foram apontados como obst√°culos para o desenvolvimento de outro tipo de pr√°ticasinfo:eu-repo/semantics/publishedVersio

    N‚ÄĎHeterocyclic Carbene-Catalyzed Convenient Benzonitrile Assembly

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    The benzonitrile unit is widely found in natural products, pharmaceuticals, and agrochemicals. Synthesis of benzonitriles has received considerable interests from the chemical community over the last few decades. Present synthetic protocols mainly rely on the pre-existing benzene core to install a cyano moiety. A new NHC-catalyzed [4 + 2]-benzannulation protocol is reported to assemble the benzonitrile framework

    Enantioselective Medium-Ring Lactone Synthesis through an NHC-Catalyzed Intramolecular Desymmetrization of Prochiral 1,3-Diols

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    A highly enantioselective intramolecular annulation reaction of 1,3-diols catalyzed by a triazolium N-heterocyclic carbene (NHC) precatalyst is disclosed, affording the corresponding medium-sized lactones in moderate to good yields with high enantioselectivities. It is worth noting that this compatible catalytic system has been successfully applied to assemble a broad range of chiral medium-sized lactones, including ones with eight-, nine-, ten-, eleven-, and twelve-membered rings
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