• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 163
  • 42
  • 20
  • 19
  • 18
  • 17
  • 13
  • 4
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 353
  • 61
  • 54
  • 34
  • 32
  • 31
  • 22
  • 20
  • 19
  • 18
  • 18
  • 18
  • 17
  • 16
  • 16
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
281

Variations Related to Print Mottle in Starch-Containing Paper Coatings

Ragnarsson, Micael January 2012 (has links)
Starch in paper coatings is known to increase the risk of print mottle in lithographic offset printing. The objective of this study was to increase the understanding of this behaviour. Four phenomena that could lead to print mottle, where the presence of starch might be important, have been identified: uneven binder migration, uneven coating mass distribution, uneven deformation during calendering and differential shrinkage. The latter three were investigated in this project. Starch-containing coating colours often have high water retention. A relationship between the water retention of the coating colours and the distribution of coating thickness was found in a pilot trial. A theory is proposed, where the surface profile of the base paper beneath the blade, that governs the coat weight distribution in blade coating, is affected by moisture from the dewatering coating colours and the compressive force exerted by the blade. Drying strategies were studied to see whether they would induce porosity variations in the coating layers. There is a strong connection between the rate of evaporation and the shrinkage of the coating layer, but no porosity variations due to the choice of drying strategy were found. Shrinkage is governed by the capillary forces. At the same capillary pressure, the coating shrinks more for some binder systems, which is suggested to be due to a weaker chemical interaction between the binder and the pigment. Oxidized starch/latex coatings, stained with a fluorescent marker, had a greater standard deviation in fluorescence intensity than CMC/latex coatings caused by a difference in either porosity or latex distribution. It was shown that calendering introduces porosity variations into the coating layer that are larger for starch-containing coatings. The drying strategies appeared to have a significant effect on these porosity variations and they correlated positively with print mottle in some cases and in another case negatively. In the case of the negatively correlated, the mottle was probably caused by variations in surface porosity existing prior to the calendering.
282

Deductions from employees’ remuneration: seeking clarity in the law

Cato, Cara January 2009 (has links)
Magister Philosophiae - MPhil / Sectoral Determination 9,1 Wholesale and Retail Sector echoes the wording found in the Basic Conditions of Employment Act2 when it comes to the section pertaining to deductions from employees’ remuneration. It is unclear how an employer may lawfully make a deduction (other than those required by law) from an employee’s remuneration in order to recover costs such as till shortages, stock losses and improper notice. Loss and damages are common problems faced not only by retailers but by all employers, yet the two governing bodies, that is, the Department of Labour and the CCMA, fail to offer any assistance to the employer in this regard. The law is unfairly biased against the employer, who may be financially unable to recover from losses caused by an employee and may face closure should it be unable to recover losses suffered. The two remedies available to the employer are civil action and criminal action against the employee. However, both have proven to be inadequate for recovering losses incurred. Furthermore, the employer will have already incurred losses and therefore can ill afford the money or the time to pursue these options. The Small Claims Court does offer some relief to a smaller employer wanting to claim to a maximum of R7000, but companies are excluded from this mechanism as the rules of the Small Claims Court specifically exclude them from using this forum. In this study, I will look at the common law principle of offset to see whether it can be applied to employers making deductions against employees for loss or damage. Notice is a quantifiable amount and is a legal debt; therefore. it should be able to be applied as an offset. Two subsections deal with deductions; after looking carefully at the wording of theses subsections I will try to determine whether the one is alternate to the other, or whether the narrow interpretation that the Department of Labour gives to the statute is accurate. A narrow interpretation of the law states that the employee must sign an acknowledgement of debt. However, employees often refuse to sign an acknowledgement of debt, thereby frustrating the law. Could this possibly have been the intentions of the drafters? Surely not, yet the Department of Labour, by having a narrow interpretation of the law, see it as such and as a result the employer is left out of pocket. In this mini-thesis, I will look at the way the law should be interpreted and the way it should be applied in practice. 1 Sectoral Determination 9: Wholesale and Retail Sector, Government Gazette No. 24207 2 The Basic Conditions of Employment Act 75 of 1997 What problems does this ambiguity create? Some problems could include a higher case load for the Department of Labour, demotivated employees, increased tension in the workplace and frustrated employers. I also consider comparative labour law to see if other countries faced with similar situations have made any allowances for such circumstances. Aims of this mini-thesis: 1. To highlight the problems and ambiguities in the interpretation and application of section 34 of the Basic Conditions of Employment Act (BCEA)3 and section 8 of the Sectoral Determination 9(SD9)4 2. To recommend, propose and encourage a practical solution for employers to implement in the workplace 3. To improve the situation for employers under the current structure. 4. To lead the legislature drafters to amend or redraft these sections
283

Synchronisation en fréquence pour l'allocation de porteuses des systèmes OFDMA en liaison montante / Synchronozation en frequence pour l'allocation de porteuses des systemes ofdma en liaison montante

Aziz, Babar 15 December 2011 (has links)
La mise en œuvre de systèmes basés OFDMA nécessite une synchronisation de la fréquence très fine en raison de l'extrême sensibilité de l'OFDMA aux décalages en fréquence porteuse (CFO). La synchronisation en fréquence devient plus difficile dans les systèmes OFDMA en liaison montante. Nos objectifs comprennent l'étude et l'analyse des problèmes résultant de décalages de fréquence et la proposition de solutions pour lutter contre ces problèmes. Nous examinons d'abord les interférences résultant de décalages de fréquence porteuse présents dans l'oscillateur du terminal utilisateur. Nous démontrons que l'on doit prendre en compte le préfixe cyclique tout en analysant les interférences résultant du CFO. Ensuite, nous montrons qu'il existe une contradiction entre la diversité de fréquence de canal et la robustesse contre le CFO. Nous proposons un compromis sous la forme d'une taille de bloc de seuil, afin de permettre un bon compromis entre la diversité des canaux et de robustesse pour les CFO pour le cas où aucune connaissances du canal n'est disponible. Quand le canal est connu, nous proposons une allocation optimale par bloc grâce à laquelle la robustesse aux CFO et à la diversité de fréquence de canal peut être réalisée en utilisant une petite taille de bloc petit pour des CFO de petite valeur. Nous proposons également une valeur CFO critique, en dessous de laquelle l'allocation optimal par bloc est très performant.Ensuite, nous proposons des solutions pour deux problèmes importants rencontrés dans un système OFDMA en liaison montante.Premièrement, nous proposons une méthode efficace pour l'estimation conjointe des réponses impulsionnelles des canaux et fréquences porteuses basée sur l'approximation polynomiale.Notre méthode d'estimation conjointe est plus simple que les méthodes existantes, sans aucune dégradation de performance. Ensuite, nous proposons une méthode de compensation de CFO basée sur l'annulation des interférences successives (SIC). La méthode d'annulation proposée réduit la complexité de mise en oeuvre quand le nombre de porteuses est important. / One of the most prominent issues in the design and implementation of OFDMA based systems is the need for a very fine frequency synchronization due to the fact that OFDMA, like OFDM, is extremely sensitive to carrier frequency offsets (CFO). The task of frequency synchronization becomes more challenging in the uplink OFDMA-based systems where one OFDMA symbol is generated by the contribution of many different users. Our goals include the study and analysis of problems resulting from frequency mismatches provide solution to combat these problems. We first look at the interference resulting from CFOs, resulting from user terminal oscillator mismatch. We demonstrate that one must take into account the cyclic prefix while analyzing interference resulting from CFO. A new analytical expression of the ICI that takes into account the effect of CFO on the cyclic prefix is proposed. Then we focus our attention on analysis of the trade-off between channel frequency diversity and robustness against CFO and show that there exists a contradiction between the two. We propose a trade-off in the form of a Threshold blocksize, to allow a good compromise between the channel diversity and robustness for CFO for the case when no CSI is available. For system where CSI is available, we propose an optimal block carrier allocation scheme through which both robustness to CFO and channel frequency diversity can be achieved with small blocksize for small CFO. We also propose a Critical CFO value, above which the performance of the optimal block carrier allocation loses interest.Next we propose solutions for two important issues encountered in an uplink OFDMA system. First, we propose an efficient method for joint estimation of channel impulse responses and carrier frequency at the receiver based on polynomial approximation. Our proposed joint estimation method is simpler than the existing methods without any performance degradation. Next we propose a CFO compensation method based on successive interference cancellation. The proposed cancellation method reduces the implementation complexity faced in case of large DFT matrices.
284

Návrh a optimalizace spínaného komparátoru v 250 nm CMOS technologii / Design and parameters optimization of latched comparator in 250 nm CMOS process

Matěj, Jan January 2017 (has links)
This diploma thesis deals with design methods and optimization techniques of dynamic latched comparators. It compares latched and continuous comparators and describes their principle. Then it analyses three popular latched comparator structures with respect to offset, speed and kickback noise. It shows practical comparator design focused on offset precision.
285

Úprava křižovatky silnice I/50 x II/416 ve Slavkově u Brna / Editing intersection of the I/50 x II/416 in Slavkov u Brna

Lakomý, Jan January 2016 (has links)
The subject of these graduation thesis is a draft of adaptation the existing indented intersection of roads I/50 and II/416 in Slavkov u Brna. Thesis include design of construction work intersection, which was made on the basis of direction research actual state and consequent capacitance calculation.
286

Modelování diferenčního proudového zesilovače / Modelling of differential current amplifier

Polák, Josef January 2013 (has links)
The aim of my diploma thesis was programming of systems for measuring AC, DC and impedance measurements. Each measuring system measures selected characteristics of current amplifier with controllable amplification DACA_N. Control programs I have created in Agilent VEE Pro 9.2. The measured data are stored to executable files in MS Excel for further processing. With created measurement programs I made measurements of eight current amplifiers. The results of individual measurements I compiled into graphs and compared with each other circuit characteristics of amplifiers. Then there is described controlling and connection of current amplifier and its construction. At the end the diploma thesis describes amplifiers with the worst and the best measured circuit characteristics. The measured values show that the amplifier DACA_N with slight differences works by theoretical assumptions and measurement systems suggested by me work with no problem.
287

Analýza internetové web-to-print aplikace malé tiskárny včetně návrhu vylepšení jejich funkcí / Analysis of an Internet Web-to-Print Application of a Small Printing Studio, Including Suggestions for Improvement of the Program's Functions

Pavlišta, Marek January 2010 (has links)
Work analysis we-to-print aplications run by company REP Tisk spol. s r. o. It contains theoretical background, analysis od the current version of the application and suggestions for new version. The emphasis was primarily on pricing variability. Key was also possibility to run the application on multiple web sites simultaneously.
288

Návrh metodiky a vytvoření vybraných programových modulů pro nastavování a snímání defektů soustružnických nástrojů pomocí laserového měřícího zařízení / The design of methodology and creating of chosen SW modules for setting and exploring of lathe tools defects using laser measuring device

Křížek, Michal January 2008 (has links)
This diploma thesis deals with possibility of a non-contact tool corrections measurement and broken tool detection on CNC lathes. For this purpose was made a methodology for measuring and application in NC program. For testing the program in praxis was used CNC lathe SPM 16 with Sinumerik 840D controller. As measuring equipment was used a laser probe NC4 by Renishaw manufacturer.
289

Offset modeling of shell elements : A study in shell element modeling using Nastran

Klarholm, David January 2016 (has links)
At Saab Aerostructures they are manufacturing a lot of parts for Airbus and Boeing. When these components are investigated using finite element analysis four-node Kirchhoff shell elements and a very fine mesh is often used. In order to make the pre-processing easier Saab would like to offset the shell mid surface from the nodal plane (the modeling surface) rather than to extract mid surfaces for the entire component. This would also make it easier to model a component which needs a thickness change later on, this since the original modeling surface could be used but with an offset of the elements in order to represent the new geometry. When offset is used in Nastran multi point constraints are created between the nodes and the shell mid surface points. All loads, which are applied in the nodal plane, are then transformed to the mid surface where the stiffness matrices, displacements and stresses are calculated. In order to be able to use this method more knowledge about its effects are needed, which is the reason for this thesis work. The offset is studied for two simpler cases, thickness variation and a 90°corner, as well as fora more complicated component called a C-bar. This is a hinge connecting the flaps to the wings of an airplane. The simpler cases are modeled using both mid surface and offset models subject to either a transverse load, an in-plane load or a bending moment. These are compared to a solid model in order to determine which is the most accurate. When mid surface modeling is used fort he thickness variation the surfaces are connected using rigid links. The conclusion made from these simulations is that using offset may give different results if the load is an in-plane load. This kind of load leads to the creation of a bending moment, which is linearly dependent on the amount of offset. The severity of this depends on the overall geometry and how this load is applied.
290

Offset-Simulation of Comparators

Graupner, Achim, Sobe, Udo 08 June 2007 (has links)
A simple methodology for determining the input referred offset voltage of comparators is presented. This in general is difficult as the output of a comparator is discrete valued. The method relies on a Monte-Carlo-Simulation with certain comparator input values and some postprocessing of the comparator output data. The comparator is always operated in its intended environment, there is no modification of the comparator itself nor some unusual stimuli required. There is also no known restriction for the type of comparators to be analyzed.

Page generated in 0.0804 seconds