Understanding the mechanism of zeolite nucleation and crystallization will enable the zeolite science community to tune zeolite properties during synthesis in order to accommodate the purposes of various applications. Thus there has been considerable research effort in "deciphering" the mechanism by studying the growth course of tetrapropylammonium (TPA)-mediated silicalite-1 using several techniques, such as dynamic light scattering (DLS), small-angle X-ray/neutron scattering (SAXS/SANS), and nuclear magnetic resonance (NMR). While these studies have generated a more comprehensive picture on the silicalite-1 growth mechanism, the general application of the mechanism and how it could be applied to other zeolite systems have not been addressed. This work initially tried to apply the insights developed from the TPAsilicalite- 1 clear solution synthesis by investigating the nanoparticles formation and zeolite growth in several tetraethyl orthosilicate (TEOS)-organocation-water solutions heated at 368 K using SAXS. The results are in contrast to TEOS-TPAOH-water mixtures that rapidly form silicalite-1 at 368 K. These results imply that the developed TPA-silicalite-1 nucleation and crystallization mechanism is not universally applicable to other zeolite systems and TPA-silicalite-1 itself could be a special case. With this in mind, the next goal of this work uses in situ SAXS to revisit silicalite-1 growth kinetics prepared by using several TPA-mimic organocations and some asymmetric geometry organocations. The results clearly show the TPA cation is an extraordinarily efficient structure-directing agent (SDA) due to its moderate hydrophobicity and perfect symmetric geometry. Any perturbation of the hydrophobicity and symmetry of SDA leads to a deterioration of zeolite growth. This work further investigates the influences of alcohol identity and content on silicalite-1 growth from clear solutions at 368 K using in situ SAXS. Several tetraalkyl orthosilicates (Si(OR)4, R = Me, Pr, and Bu) are used as the alternative silica sources to TEOS in synthesizing silicalite-1. Increasing the alcohol identity hydrophobicity or lowering the alcohol content enhances silicalite-1 growth kinetics. This implies that the alcohol identity and content do affect the strength of 1) hydrophobic hydration of the SDA and 2) the water-alcohol interaction, through changing the efficiency of the interchanges between clathrated water molecules and solvated silicate species.

The paper presents a posteriori error estimators for the stationary Stokes problem. We consider anisotropic finite element discretizations (i.e. elements with very large aspect ratio) where conventional, isotropic error estimators fail. Our analysis covers two- and three-dimensional domains, conforming and nonconforming discretizations as well as different elements. This large variety of settings requires different approaches and results in different estimators. Furthermore many examples of finite element pairs that are covered by the analysis are presented. Lower and upper error bounds form the main result with minimal assumptions on the elements. The lower error bound is uniform with respect to the mesh anisotropy with the exception of nonconforming 3D discretizations made of pentahedra or hexahedra. The upper error bound depends on a proper alignment of the anisotropy of the mesh which is a common feature of anisotropic error estimation. In the special case of isotropic meshes, the results simplify, and upper and lower error bounds hold unconditionally. Some of the corresponding results seem to be novel (in particular for 3D domains), and cover element pairs of practical importance. The numerical experiments confirm the theoretical predictions and show the usefulness of the anisotropic error estimators.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 136-143). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 136-143). Also available on the Internet.

Fly ash has been used extensively to control deleterious alkali-silica reaction in concrete. The majority of fly ashes can be used to control ASR induced expansion. Fly ashes with high CaO contents are less effective at reducing expansion and fly ashes with high alkali contents can be counter active. Class C fly ashes are less effective at reducing the pH of the pore solution because they are less pozzolanic. The pozzolanic reaction in Class F fly ashes enhances the ability for the hydration products to bind alkalis. This prevents the availability of these alkalis for ASR. This project aims to characterize fly ash in a way that best predicts how it will perform in concrete with an emphasis on ASR. Fly ashes with a variety of chemical compositions were evaluated using a range of analytical and characterization techniques. Research data from several universities were used to correlate their long term data with this project’s accelerated tests. This research aimed at evaluating the mineralogical, chemical, and physical characteristics that most affect the ability of a given fly ash to prevent ASR-induced expansion and cracking. / text

We compare the performance of the perturbation-based (local) portfolio solution method of Devereux and Sutherland (2010a, 2011) with a global solution method. We find that the local method performs very well when the model is designed to capture stylized macroeconomic facts and countries/agents are symmetric, i.e. when the latter have similar size, face similar risks and trade assets with similar risk properties. It performs less satisfactory when the agents engaged in financial trade are asymmetric. The global solution method performs substantially better when the model is parameterized to match the observed equity premium, a key stylized finance fact. (authors' abstract) / Series: Department of Economics Working Paper Series

The purpose of this study has been to examine what assistance potential mothers’ of the next generation suggest for girls, in order for all to be able to complete primary education. This has been investigated through asking 36 women age 18-25, what obstacles they see for socio- economically constrained girls. They have also been asked about how they think these obstacles can be altered for the next generation. The study method has been focus group interviews. When analysing the interview material Empowerment theory and the Salutogenic theory have been applied. The main solutions presented by the respondents is support in income generating activities for the poorest mothers and advocacy for girls’ education. The best way of supporting mothers would according to the respondents be for the Ethiopian Government to assist the poorest mothers to start and run businesses. Religious leaders are perceived to be the possible assistance provider in position to affect the public opinion making the whole society more willing to invest in girls’ educational chances.

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Praktinėje žmonių veikloje (transporto sistemoje, valdyme, projektuojant konstrukcijas ir kt.) dažnai reikia rinktis vieną sprendinį iš kelių galimų. Iškyla uždavinys – rasti geriausią sprendinį. Pavyzdžiui, įmonėje reikia taip organizuoti gamybą, kad pelnas, gautas už pagamintą produkciją, būtų didžiausias; reikia taip suplanuoti produktų išvežimą iš siuntimo punktų (sandėlių, bazių) į paskirties punktus (parduotuves, statybos aikšteles ir t. t.), kad bendrosios transportavimo išlaidos būtų mažiausios. Darbo tikslas išanalizuoti optimizavimo uždavinius transporte, sprendžiant transporto uždavinius įvairiais būdais, naudojant skirtingas programas ir atitinkamus jų modelius. Palyginti programų interfeisus, susipažinti su jų aplinka ir padaryti išvadas, su kuria programa yra patogu ir optimalu spręsti specializuotus uždavinius. Šio darbo teorinėje dalyje pirmiausiai buvo susipažinta su pagrindinėmis sąvokomis, kurios yra naudojamos nagrinėjant šią problemą. Buvo susipažinta su Solver, WinQSB ir Simplex programomis. Išnagrinėjome, kaip reikia dirbti su Solver, WinQSB ir Simplex programomis, kad būtų galima surasti optimalų sprendinį konkrečių uždavinių transporto sferoje. Darbe taip pat buvo susipažinta su pagrindinėmis Network Modeling programos Transportation Problem (transporto uždavinių sprendimo modulio) – darbo principais, kuris priklauso WinQSB programai. Šią problemą domėtis bei galvoti kaip ją spręsti ir tobulinti turimas žinias nusprendžiau dirbdama transporto... [toliau žr. visą tekstą] / Fairly often it is necessary choose one solution out of several possible ones in the practical human activities (in transport system, management, design of structures, etc.). Naturally, then it is necessary to find the best solution. For example, a company has to arrange its production so as to maximise the profit from the production; product transportation from dispatch points (storehouses, centres) to destination (shops, construction sites, etc.) is to be planned so as to minimise the overall transportation costs. The objective of the work is to analyse the methods of linear programming when solving transportation problems by applying various tools, using different software and their respective models, to compare the software interfaces, get acquainted with their environment and to conclude which of the programmes is the most convenient and optimum for the solution of specific problems. The theoretical part of the work, first of all, introduces the main definitions used in the analysis of the problem. Solver, WinQSB and Simplex software was introduced. It was analysed, how one is to work with Solver, WinQSB and Simplex software to find an optimum solution when dealing with a particular problem of the transport sector. The work also introduces the main principles when working with Transportation Problem module of Network Modelling, which is a part of WinQSB software. I had decided to analyse the problem and improve my knowledge while working in the transport sector – then... [to full text]

The objective of the research is to diagnose problems of the employee motivation system of UAB “Nukas” and to anticipate their solution tendencies. During the research, upon evaluation of main weakness of groups of motivation parameters and upon accomplishment of analysis of factors, decreasing motivation of employees according various demographical variables, it was determined that the main problems of the system of employees motivation are insufficient possibilities to raise qualification, insufficient level of available wages and insufficient possibility to participate in management of the enterprise. In order to solve the problems of stimulation of employees, the management of the enterprise has to choose the most optimal methods of management of employees, considering material and moral needs of the employees and individual their characteristics.