Recent advances in imaging technology have resulted in a proliferation of images across different media. Before it reaches the end user, these signals undergo several transformations, which may introduce defects/artifacts that affect the perceived image quality. In order to design and evaluate these imaging systems, perceived image quality must be measured. This work focuses on analysis of print image defects and characterization of printer artifacts such as banding and graininess by using a human visual system (HVS) based framework. Specifically the work addresses the prediction of visibility of print defects (banding and graininess) by representing the print defects in terms of the orthogonal wavelet and sinusoidal basis functions and combining the detection probabilities of each basis functions to predict the response of the human visual system (HVS). The detection probabilities for basis function components and the simulated print defects are obtained from separate subjective tests. The prediction performance from both the wavelet based and sine based approaches is compared with the subjective testing results .The wavelet based prediction performs better than the sinusoidal based approach and can be a useful technique in developing measures and methods for print quality evaluations based on HVS.

Thesis (M.S.)--Rochester Institute of Technology, 1988. / Includes bibliographical references.

Thesis (Masters Diploma (Technology)-- Cape Technikon, Cape Town,1988 / Brown Davis and McCorquodale is one of the major suppliers of cheques to the banking industry. To produce these cheques they use a number of different print systems, one of which comprises of a minicomputer, an industry standard tape deck and two printers, a Diablo daisywheel and a Control Data Corporation (CDC) printer which was extensively modified to cater for the requirements of the cheque printing industry. The CDC printer is used to print the code line on the cheques using magnetic ink. After each line is printed the computer sends a form feed command which causes the printer to throw paper. This throw is controlled by a paper tape, known as a Vertical Format Unit tape, or rather a VFU tape. This tape has holes punched into it at specific places which determine the amount of paper throw also known as vertical feed. The holes are sensed by brushes which are pulled up to 5 volt when they pass over a hole and touch a roller connected to the 5 volt line. This system, being of an electro-mechanical nature, is prone to faults and causes much down time due to mechanical wear on the brushes and dirt on the roller. This means that the brushes have to be adjusted and therefore also means that the timing has to be readjusted each time. The timing relationships are discussed in Section 2.B

In the print industry for several segments and a segment of this is on printed sheet metal. This segment is the preparation of steel plates for the manufacture of cans of industry both for domestic use, as industrial. The treatment of steel is based on the application of varnishes and paints that protect the metal against rust and assists in the decoration and customization of the cans. This is done by machine known as appropriate machines coaters and lithographs. Basically identical in its structure, are composed of a truck for entry, intermediate mats, the machine itself, mats in and out of the oven and a wake of staples used to transport the sheets of steel in the oven for drying of products. Today most of the machines in that market segment is old and often driven only by an electric motor. The variation in velocity occurs through variable electromechanical and / or electromagnetic the process of timing and positioning of the sheet along the machine is done through mechanical systems of gears, reducers boxes, straps and transmission. Usually have large levels of defects present, forcing its shutdown for maintenance and still have relatively low rate of production compared to the more modern machines. The objective is to suggest the replacement of all mechanical transmission of a fully electronic system through the use of alternating current motors, inverters and frequency of Programmable Logic Controller (PLC) so that the system for timing and position is done by encoders attached to the PLC, ensuring the smooth functioning of the whole machine. Using this system, the rate of maintenance is reduced and the speed of the machine will be increased between 5% and 10%, ensuring greater production. / Na indústria de impressão há vários segmentos e um destes segmentos é o da impressão em folhas metálicas. Este segmento consiste na preparação das chapas de aço para a indústria de fabricação de latas tanto para uso doméstico, quanto industrial. O beneficiamento do aço tem por base a aplicação de vernizes e tintas que protegem o metal contra a ferrugem e auxilia na decoração e personalização das latas. Este processo é realizado por meio de máquinas apropriadas conhecidas como envernizadeiras e litografias. Basicamente idênticas em sua estrutura, são compostas de um empilhador de entrada, esteiras intermediárias, a máquina propriamente dita, esteiras de entrada e saída da estufa e ainda uma esteira de grampos usados para transportar as folhas de aço dentro da estufa para a secagem dos produtos. Hoje a maioria das máquinas existentes nesse segmento de mercado é antiga e, muitas vezes, acionadas por apenas um motor elétrico. A variação de velocidade se dá por meio de variadores eletromecânicos e/ou eletromagnéticos cujo processo de sincronismo e posicionamento da folha ao longo da máquina se dá através de sistemas mecânicos de engrenagens, caixas redutoras, correias e transmissões. Geralmente apresentam grandes índices de defeitos, obrigando o seu desligamento para a manutenção e ainda possuem velocidade de produção relativamente baixas, se comparadas com as máquinas mais modernas. O objetivo do trabalho é sugerir a substituição do conjunto de transmissão mecânica por um sistema totalmente eletrônico através do uso de motores de corrente alternada, inversores de freqüência e controlador lógico programável (CLP), de modo que o sistema de sincronismo e posição seja feito por encoders acoplados ao CLP, garantindo o bom funcionamento de toda a máquina. Com o uso deste sistema, o índice de manutenção é reduzido e a velocidade da máquina é aumentada entre 5% e 10%, garantindo uma maior produção.

Heritage iron objects are ubiquitous in the archaeological assemblage, frequently covered in thick, chloride-containing corrosion layers. Accurate monitoring of their corrosion rates is crucial for continued preventative conservation. Measurement of storage environment corrosivity is commonplace for a variety of metals, but use un-corroded metal as a proxy. Corrosion rates measured will be different with respect to chloride infused and corroded artefacts and data recovered difficult to reconcile with actual artefact degradation. Electrical resistance corrosion monitors have been applied to create proxy corrosion rates for various metals in industry, academia and heritage contexts. Pre-corrosion of such has previously been shown to be effective in providing altered corrosion rates in atmospheric environments. This research sets out to develop and refine the manufacture of such probes, to create sensors which will corrode similarly to chloride infested heritage iron and can be used in heritage environments to inform conservation strategy. Photochemical milling was used to create ERCM. Salt loading on the surface was achieved through a piezoelectric inkjet printer, shown to be adept at printing a variety of salt concentrations (down to 4μg/cm) and patterns, with consistency, regularity and reliability. The results of the methodology show the potential of the technique for future salt loading and corrosion testing applications. Corrosion products were grown on the treated ERCM by controlled atmospheric corrosion, shown to create a constant corrosion layer, no significant localised corrosion and good reproducibility. The products formed were shown to be compositionally similar to those found on archaeological iron. The sensors have been tested in both stable and dynamic relative humidity environments, within a test chamber and in ersatz heritage type, desiccated boxes. The corrosion rates and reactions were compared to those of heritage iron. Pre-corroded ERCM are shown to give similar corrosion rates to heritage iron; though direct calibration was not possible, further research is likely to remedy this. The final outcomes of the project are discussed with respect to the closeness of fit between proxy and archaeological iron corrosion rate data, benefits and shortcomings of the system and how the corrosion data affects current conservation understanding. It is concluded that the technique can detect corrosion rates down to storage relative humidity levels, provides more accurate representation of corrosion rate for chloride infested iron objects than bare metal ERCM, can be calibrated to suite specific objects and could represent excellent cost-effectiveness for environmental monitoring in heritage institutions.

No description available.

There is currently an interest in optimizing the structural design to improve materials' strength to weight ratio or improve stiffness for energy absorption. As such, cellular structures are continuously studied and improved. However, it is a well-known fact in the literature that one primary mechanism of failure of a honeycomb is the formation of shear bands. The impacts of these shear bands bring many questions and unknowns, especially when the cellular structures are created with the increasingly popular manufacturing technique of 3D printing. Therefore, understanding the deformations in 3D printed honeycomb structures is necessary to explain the behavior of materials generated through new additive manufacturing techniques and further the knowledge of the deformation localization and, consequently, formations of shear bands in the deformation process of cellular structures.In the first phase of this work, samples with a unit cell regular hexagonal honeycomb format were designed and manufactured using masked-stereolithography (M-SLA). After the curing process, the samples were prepared with a paint application in the format of speckle, and DIC was realized in a compression experiment to identify and analyze the presence of high strain regions indicating the presence of shear bands. A second phase was then conducted, aiming to consider the control and manipulation of the shear band through the utilization of relief holes. The results demonstrated that adding incisions in specific parts of the polymeric honeycomb makes it possible to change its strain spread through the shear band and change its toughness.

This thesis deals with the design and realisation of the stereolithographic 3D printer using DLP projector. The work describes the selection of suitable components for the printer´s mechanical construction and manufacturing of this construction, the solution of printer´s electronics and creation of the printer´s host software and firmware. Recommendations based on executed experiments for the parameters´ values settings have been given here.

No description available.

Three-dimensional (3D) bio printing offers a wide range of applications, including the placement, design, and patterning of biological components such as living cells, nucleic acids, tissues, and many more. Bioprinting has seen great growth and breakthroughs in recent years, particularly in 3D printing. The company (which do not want to be named) produce a user- friendly and adaptable bioprinter that provides the best bioprinting experience.  This thesis examines the environmental consequences of a 3D printer, through Life Cycle Assessment (LCA) over its lifetime which is anticipated to be 1 year for the study. To examine the impacts of the 3D printer over its lifetime, a comparative life cycle assessment (Comparative LCA) and attributional life cycle assessment (ALCA) was undertaken between the supply chains known as linear supply chain (LSC) and circular supply chain (CSC). Global warming (GW), terrestrial acidification (TA), freshwater eutrophication (FET), terrestrial ecotoxicity (TEC), freshwater ecotoxicity (FEC), marine ecotoxicity (MEC), land use (LU), and water consumption (WC) are the impact categories chosen for the study from ReCiPe 2016 (H) Midpoint.  According to the LCA results, the impacts generated by CSC are smaller than those contributed by LSC, and the impact categories that are most and least affected are recognized. Furthermore, from the 3D printer, potential hotspots with higher contributions were discovered. Airway transfer of 3D printer’s components from their manufacturing site to the company had a significant impact on the impact categories chosen. Printed Circuit Boards (PCB) used in 3D printers are another influential component that has a significant impact on the impact categories. When specifically looking, the manufacture of Integrated Circuits (IC) has a greater impact, which reflects on PCB production.  To identify the opportunities and improve 3D printer’s environmental performance, a sensitivity analysis is carried out, which yields results on how to improve its environmental performance. As a result, it is suggested that airway transportation be modified with seaway transportation, that virgin aluminium and copper materials be replaced with its scrap material / Tredimensionell (3D) bioprinting erbjuder en mängd olika applikationer, inklusive placering, design och mönster av biologiska komponenter, såsom levande celler, nukleinsyror, vävnader och mer. De senaste åren har bioprinting fått många genombrott och vuxit mycket, framför allt inom 3D-printing. Företaget (som inte vill bli namngivet) producerar en användarvänlig och anpassningsbar bioprinter som ger den bästa bioprinterupplevelsen.  Detta examensarbete undersöker den miljöpåverkan som en 3D-skrivare har, genom livscykelanalys (LCA) under sin livslängd, som beräknas vara 1 år för denna studie. För att undersöka 3D-skrivarens påverkan under dess livstid har en jämförande livscykelanalys (Comparative LCA) och attributionell livscykelanalys genomförts mellan försörjningskedjorna, som kallas linjär försörjningskedja (LSC) och cirkulär försörjningskedja (CSC). Global uppvärmning (GW), terrestrisk försurning (TA), sötvattenseutrofiering (FET), terrestrisk ekotoxicitet (TEC), sötvattenekotoxicitet (FEC), marin ekotoxicitet (MEC), markanvändning (LU) och vattenförbrukning (WC) är kategorier valda för studier från ReCiPe 2016 (H) Mid Point. Enligt LCA-resultat är miljöpåverkan från CSC mindre än den som LSC bidrar med. Dessutom, med 3D-skrivare, har potentiella hotspots med högre bidrag upptäckts.  . Luftburen överföring av 3D-skrivarkomponenter från deras tillverkningsplats till företaget hade en inverkan på de berörda kategorierna. Printed Circuit Boards (PCB) som används i 3D-skrivare är en annan påverkande komponent. Mer specifikt har tillverkning av integrerade kretsar (IC) en stor inverkan.  För att, identifiera utsläpp och möjligheter och förbättra 3D-skrivarens miljöprestanda, genomförs en känslighetsanalys som ger resultat om hur man kan förbättra dess miljöprestanda. Som ett resultat föreslås att flygtransporter ersätts med sjötransporter, att jungfruligt aluminium och kopparmaterial ersätts med dess ersätts material.