77 resultados para K-12 teacher preparation


Relevância:

30.00% 30.00%

Publicador:

Resumo:

10 x 20 cm

Relevância:

30.00% 30.00%

Publicador:

Resumo:

11 x 20 cm

Relevância:

30.00% 30.00%

Publicador:

Resumo:

14 x 22 cm

Relevância:

30.00% 30.00%

Publicador:

Resumo:

kuv., 10 x 18 cm

Relevância:

30.00% 30.00%

Publicador:

Resumo:

kuv., 10 x 18 cm

Relevância:

30.00% 30.00%

Publicador:

Resumo:

kuv., 21 x 29 cm

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The overall aim of this study was to investigate and examine teacher educators’ conceptions and experiences of quality of teacher education. The research interest therefore was two-fold: a) to deepen understanding of the concept quality and b) scrutinize experiences of teacher educators of quality enhancement. To achieve this ambition the study was conducted in the context of a newly established university college-based teacher education in Tanzania. Two research questions guided the study. The first focused on investigating how teacher educators conceived quality in the domain of teacher education and the second intended to explore teacher educators’ experiences of quality enhancement. The theoretical framework of the study centered on the concepts of teacher education, quality, and criteria for quality enhancement. Phenomenographic and phenomenological approaches under the main umbrella of qualitative research design were selected. Twenty five teacher educators participated in the study. Interviews were used for the collection of the data. The results of the first research question, in brief, indicate that teacher educators’ conceptions of quality are expressed in two main categories, namely, outstanding academic scholarship and adequate professional scholarship. Quality as outstanding academic scholarship was illustrated by two subcategories: excellence and positive transformation. While the former was composed of two aspects, the latter was demonstrated by three aspects. Quality as adequate professional scholarship was described in three sub-categories. The first was improved teaching competency, consisting of two aspects. The second was conscious research orientation, which is displayed by three aspects, and the last was enhancing the ability to reflect, represented by two aspects. The results of the second research question, which focused on exploring teacher educators’ experience of quality enhancement, were classified into two main categories of description: insufficient programs of teacher education and unsatisfactory professional development of teacher educators. From the two categories, the strengths, weaknesses, opportunities and challenges related to programs of educating teachers, particularly curriculum development and implementation, and the professional development of educators, were exposed. Since the ambition of conducting the study was to deepen the understanding by producing insight that would act as a platform for appraising and enhancing the quality of teacher education, the results hopefully can be used for the development of the quality of teacher education in Tanzania.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Collaboration is essential for successful new product development. In the preparation for ramp-up production collaboration between R&D and supply chain functions is crucial. This thesis examines the meaning of collaboration and the effects of collaboration between R&D and supply chain. The aim of this thesis is to analyse and advice on how to improve the collaboration between the research and development department and supply chain within the preparation for rampup process. This thesis begins by introducing the reader to the product development methodologies and collaboration literature. The following part of the thesis describes the current situation and the results of the qualitative research. The last part of the thesis will explain the improvement suggestions. The main improvement suggestions are clarification of the processes and responsibilities and the introduction of a kick-off meeting.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Kaupan omat merkit pitävät markkinaosuuden kasvua yllä Euroopassa, olipa kyse sitten kehittyvistä vähittäiskaupan markkinoista Idässä tai vakiintuneimmista vähittäiskaupan alueista. Vähittäismyyjien omien merkkien osuus myytävistä tuotteista on yli 40 prosenttia monissa Euroopan maissa. Tämän tutkielman ensisijaisena tarkoituksena on tutkia kaupan omien merkkien roolia päivittäistavarakaupan tuotevalikoimassa. Tutkielman empiirisessä osiossa kaupan oman merkin roolia päivittäistavarakaupan tuotevalikoimassa havainnollistetaan Ruokakeskon Pirkka-tuotemerkin kautta. Tutkielman tarkoitusta lähestytään tarkentavien osakysymysten avulla. Teoriasta haetaan vastauksia kysymyksiin: 1. Millaisia kaupan omien merkkien tyyppejä tutkijat ovat tunnistaneet? 2. Millaisia markkinointistrategioita kaupalla niiden käyttöön liittyy? 3. Millaisia tavoitteita kauppa asettaa yleisesti omille merkeilleen? Empiirisen tutkimuksen avulla pyritään vastaamaan kysymyksiin: 1. Minkä tyyppinen kaupan oma merkki on Ruokakeskon Pirkka-brändi ja millainen on Pirkka-brändin markkinointistrategia? 2. Mitä tavoitteita Ruokakesko on Pirkka-brändilleen asettanut? 3. Vastaako ostokäyttäytyminen Ruokakeskon Pirkka-brändille asettamia tavoitteita? Tutkimusstrategiana on surveytutkimus sekä tapaustutkimus. Johtuen siitä, että kahdessa ensimmäisessä osakysymyksessä analyysiyksikkö on eri kuin kolmannessa osakysymyksessä käytetään tutkielmassa sekä laadullista että määrällistä tutkimusotetta. Kvalitatiivista sekä kvantitatiivista tutkimusotetta yhdistelemällä onnistutaan saamaan hyvä kokonaiskuva analyysiyksiköistä. Aineistoa kerättiin useammasta lähteestä. Päätutkimusmenetelmiä oli kaksi: kyselytutkimus sekä tutkimushaastattelu. Kyselytutkimuksen aineisto kerättiin Forssan K-citymarketissa asiakkailta kysymyslomakkeen avulla. Otannan kooksi muodostui 295 täytettyä kysymyslomaketta. Vastaukset analysoitiin IBM SPSS Statistics 20 tilasto-ohjelman avulla. Haastattelututkimus suoritettiin avoimena haastattelua. Ei ole täysin yksiselitteistä minkä tyyppinen kaupan oma merkki tai millainen rooli Ruokakeskon omalla merkillä Pirkalla on. Pirkka-brändille asetetut keskeisimmät tavoitteet ovat erilaistaa kilpailevista päivittäistavarakauppaketjuista, tarjota paremmat katteet sekä luoda kuvaa vähittäismyyjästä. Kuluttajat ostavat Pirkka-tuotteita pääasiallisesti hinnan takia.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Asymmetric synthesis using modified heterogeneous catalysts has gained lots of interest in the production of optically pure chemicals, such as pharmaceuticals, nutraceuticals, fragrances and agrochemicals. Heterogeneous modified catalysts capable of inducing high enantioselectivities are preferred in industrial scale due to their superior separation and handling properties. The topic has been intensively investigated both in industry and academia. The enantioselective hydrogenation of ethyl benzoylformate (EBF) to (R)-ethyl mandelate over (-)-cinchonidine (CD)-modified Pt/Al2O3 catalyst in a laboratory-scale semi-batch reactor was studied as a function of modifier concentration, reaction temperature, stirring rate and catalyst particle size. The main product was always (R)-ethyl mandelate while small amounts of (S)-ethyl mandelate were obtained as by product. The kinetic results showed higher enantioselectivity and lower initial rates approaching asymptotically to a constant value as the amount of modifier was increased. Additionally, catalyst deactivation due to presence of impurities in the feed was prominent in some cases; therefore activated carbon was used as a cleaning agent of the raw material to remove impurities prior to catalyst addition. Detailed characterizations methods (SEM, EDX, TPR, BET, chemisorption, particle size distribution) of the catalysts were carried out. Solvent effects were also studied in the semi-batch reactor. Solvents with dielectric constant (e) between 2 and 25 were applied. The enantiomeric excess (ee) increased with an increase of the dielectric coefficient up to a maximum followed by a nonlinear decrease. A kinetic model was proposed for the enantioselectivity dependence on the dielectric constant based on the Kirkwood treatment. The non-linear dependence of ee on (e) successfully described the variation of ee in different solvents. Systematic kinetic experiments were carried out in the semi-batch reactor. Toluene was used as a solvent. Based on these results, a kinetic model based on the assumption of different number of sites was developed. Density functional theory calculations were applied to study the energetics of the EBF adsorption on pure Pt(1 1 1). The hydrogenation rate constants were determined along with the adsorption parameters by non-linear regression analysis. A comparison between the model and the experimental data revealed a very good correspondence. Transient experiments in a fixed-bed reactor were also carried out in this work. The results demonstrated that continuous enantioselective hydrogenation of EBF in hexane/2-propanol 90/10 (v/v) is possible and that continuous feeding of (-)-cinchonidine is needed to maintain a high steady-state enantioselectivity. The catalyst showed a good stability and high enantioselectivity was achieved in the fixed-bed reactor. Chromatographic separation of (R)- and (S)-ethyl mandelate originating from the continuous reactor was investigated. A commercial column filled with a chiral resin was chosen as a perspective preparative-scale adsorbent. Since the adsorption equilibrium isotherms were linear within the entire investigated range of concentrations, they were determined by pulse experiments for the isomers present in a post-reaction mixture. Breakthrough curves were measured and described successfully by the dispersive plug flow model with a linear driving force approximation. The focus of this research project was the development of a new integrated production concept of optically active chemicals by combining heterogeneous catalysis and chromatographic separation technology. The proposed work is fundamental research in advanced process technology aiming to improve efficiency and enable clean and environmentally benign production of enantiomeric pure chemicals.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Enantiopure intermediates are of high value in drug synthesis. Biocatalysis alone or combined with chemical synthesis provides powerful tools to access enantiopure compounds. In biocatalysis, chemo-, regio- and enantioselectivity of enzymes are combined with their inherent environmentally benign nature. Enzymes can be applied in versatile chemical reactions with non-natural substrates under synthesis conditions. Immobilization of an enzyme is a crucial part of an efficient biocatalytic synthesis method. Successful immobilization enhances the catalytic performance of an enzyme and enables its reuse in successive reactions. This thesis demonstrates the feasibility of biocatalysis in the preparation of enantiopure secondary alcohols and primary amines. Viability and synthetic usability of the studied biocatalytic methods have been addressed throughout this thesis. Candida antarctica lipase B (CAL-B) catalyzed enantioselective O-acylation of racemic secondary alcohols was successfully incorporated with in situ racemization in the dynamic kinetic resolution, affording the (R)-esters in high yields and enantiopurities. Side reactions causing decrease in yield and enantiopurity were suppressed. CAL-B was also utilized in the solvent-free kinetic resolution of racemic primary amines. This method produced the enantiomers as (R)-amides and (S)-amines under ambient conditions. An in-house sol-gel entrapment increased the reusability of CAL-B. Arthrobacter sp. omega-transaminase was entrapped in sol-gel matrices to obtain a reusable catalyst for the preparation enantiopure primary amines in an aqueous medium. The obtained heterogeneous omega-transaminase catalyst enabled the enantiomeric enrichment of the racemic amines to their (S)-enantiomers. The synthetic usability of the sol-gel catalyst was demonstrated in five successive preparative kinetic resolutions.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Työssä on tutkittu laboratoriokokeen ja elementtimenetelmän avulla eri geometrioiden vaikutusta sekundääriseen momentin syntymiseen K-liitoksella. Kokeen liitos on tehty S700-lujuusluokan Ruukin Optim 700 plus MH nelikulmaisista rakenneputkista (RHS). Elementtimalleissa on käytetty geometrista ja materiaalista epälineaarisuutta ennustamaan liitoksen muodonmuutoskykyä ja laskennallista kestävyyttä. Liitoksen elementtimalleissa muutettavia geometrioita ovat: vapaaväli, uumasauvan ja paarteen välinen kulma, paarteen seinämän paksuus, liitoksen eksentrisyys ja uumasauvan ja paarteen leveyden suhde. Laboratoriokokeen liitoksen vetouumasauvassa vaikuttava sekundäärisen momentin aiheuttama jännitys on noin 25 % vetouumasauvan myötörajasta. Suurin sekundäärinen momentti syntyy, kun vapaaväliä pienennetään ja uumasauvaa kavennetaan paarteeseen nähden. Eurocode 3:n mitoitusohjeita voidaan elementtimallien perusteella soveltaa tietyille geometrioille turvallisesti.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The objective of this thesis was to study the effect of pulsed electric field on the preparation of TiO2 nanoparticles via sol-gel method. The literature part deals with properties of different TiO2 crystal forms, principles of photocatalysis, sol-gel method and pulsed electric field processing. It was expected that the pulsed electric field would have an influence on crystallite size, specific surface area, polymorphism and photocatalytic activity of produced particles. TiO2 samples were prepared by using different frequencies and treatment times of pulsed electric field. The properties of produced TiO2 particles were examined X-ray diffraction (XRD), Raman spectroscopy and BET surface area analysis. The photocatalytic activities of produced TiO2 particles were determined by using them as photocatalysts for the degradation of formic acid under UVA-light. The photocatalytic activities of samples produced with sol-gel method were also compared with the commercial TiO2 powder Aeroxide® (Evonic Degussa GmbH). Pulsed electric field did not have an effect on the morphology of particles. Results from XRD and Raman analysis showed that all produced TiO2 samples were pure anatase. However, pulsed electric field did have an effect on crystallite size, specific surface area and photocatalytic activity of TiO2 particles. Generally, the crystallite sizes were smaller, specific surface areas larger and initial formic acid degradation rates higher for samples that were produced by applying the pulsed electric field. The higher photocatalytic activities were attributed to larger surface areas and smaller crystallite sizes. Though, with all of the TiO2 samples produced by the sol-gel method the initial formic acid degradation rates were significantly slower than with the commercial TiO2 powder.