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Desenvolvimento de processo de produção de conjuntos eletrodo-membrana-eletrodo para células a combustível baseadas no uso de membrana polimérica condutora de prótons (PEMFC) por impressão a tela; Development of a membrane electrode assembly production process for proton exchange membrane fuel cell (PEMFC) by sieve printing

Bonifacio, Rafael Nogueira
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 30/03/2010 PT
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35.9%
Energia é um recurso que historicamente apresenta tendência de crescimento de demanda. Projeções indicam que, para suprir as necessidades energéticas do futuro, será necessário um uso massivo do hidrogênio como combustível. O uso de sistemas de célula a combustível baseada no uso de membrana polimérica condutora de prótons (PEMFC) tem características que permitem sua aplicação para geração de energia elétrica em aplicações estacionárias, automotivas e portáteis. O uso de hidrogênio como combustível para PEMFC apresenta a vantagem de resultar em baixa emissão de poluentes quando comparado às dos combustíveis fósseis. Para que ocorram as reações em uma PEMFC é necessária a construção de conjuntos eletrodo-membrana-eletrodo (MEA), sendo o processo de produção de MEAs e os materiais utilizados, relevantes no custo final do kW instalado para geração de energia por sistemas de célula a combustível, o que é, atualmente, uma barreira tecnológica e financeira para a aplicação em grande escala desta tecnologia. Nesse trabalho foi desenvolvido um processo de produção de MEAs por impressão a tela que apresenta alta reprodutibilidade, rapidez e baixo custo. Foram desenvolvidos o processo de impressão a tela e a composição de uma tinta precursora da camada catalisadora (TPCC)...

A stable solution-processed polymer semiconductor with record high-mobility for printed transistors

Li, Jun; Zhao, Yan; Tan, Huei Shuan; Guo, Yunlong; Di, Chong-An; Yu, Gui; Liu, Yunqi; Lin, Ming; Lim, Suo Hon; Zhou, Yuhua; Su, Haibin; Ong, Beng S.
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 18/10/2012 EN
Relevância na Pesquisa
35.91%
Microelectronic circuits/arrays produced via high-speed printing instead of traditional photolithographic processes offer an appealing approach to creating the long-sought after, low-cost, large-area flexible electronics. Foremost among critical enablers to propel this paradigm shift in manufacturing is a stable, solution-processable, high-performance semiconductor for printing functionally capable thin-film transistors — fundamental building blocks of microelectronics. We report herein the processing and optimisation of solution-processable polymer semiconductors for thin-film transistors, demonstrating very high field-effect mobility, high on/off ratio, and excellent shelf-life and operating stabilities under ambient conditions. Exceptionally high-gain inverters and functional ring oscillator devices on flexible substrates have been demonstrated. This optimised polymer semiconductor represents a significant progress in semiconductor development, dispelling prevalent skepticism surrounding practical usability of organic semiconductors for high-performance microelectronic devices, opening up application opportunities hitherto functionally or economically inaccessible with silicon technologies, and providing an excellent structural framework for fundamental studies of charge transport in organic systems.

Secondary metabolite credentials of Evolvulus alsinoides by high performance thin layer chromatography (HPTLC)

Gomathi, Duraisamy; Kalaiselvi, Manokaran; Ravikumar, Ganesan; Sophia, Dominic; Gopalakrishnan, Velliyur Kanniappan; Uma, Chandrasekar
Fonte: Editorial Department of Journal of Biomedical Research Publicador: Editorial Department of Journal of Biomedical Research
Tipo: Artigo de Revista Científica
EN
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45.73%
Plants and plant-based products are the bases of many modern pharmaceuticals that are current in use today for various diseases. The aim of the study was to investigate the biochemical constituents and high performance thin layer chromatography (HPTLC) finger printing of the ethanolic extract of Evolvulus alsinoides. Phytochemical screening was done by standard procedures and HPTLC method was also established to analyze alkaloids, flavonoids and phenolic compounds from the ethanolic extract of Evolvulus alsinoides. Preliminary phytochemical screening showed that ethanol extracted more secondary metabolites than other solvents. HPTLC fingerprinting analysis showed the presence of various alkaloids, flavonoids and phenols (quercetin) in the ethanolic extract. It can be concluded that Evolvulus alsinoides may serve as a source of potent antioxidants that may be used in the prevention of various diseases such as cancer, diabetes and cardiovascular diseases due to the presence of phenolic compounds. HPTLC finger print of Evolvulus alsinoides may be useful in the differentiation of the species from adulterants and act as a biochemical marker for this medicinally important plant in the pharmaceutical industry and plant systematic studies.

Capillary flow of amorphous metal for high performance electrode

Kim, Se Yun; Kim, Suk Jun; Jee, Sang Soo; Park, Jin Man; Park, Keum Hwan; Park, Sung Chan; Cho, Eun Ae; Lee, Jun Ho; Song, In Yong; Lee, Sang Mock; Han, In Taek; Lim, Ka Ram; Kim, Won Tae; Park, Ju Cheol; Eckert, Jürgen; Kim, Do Hyang; Lee, Eun-Sung
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 15/07/2013 EN
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35.79%
Metallic glass (MG) assists electrical contact of screen-printed silver electrodes and leads to comparable electrode performance to that of electroplated electrodes. For high electrode performance, MG needs to be infiltrated into nanometer-scale cavities between Ag particles and reacts with them. Here, we show that the MG in the supercooled state can fill the gap between Ag particles within a remarkably short time due to capillary effect. The flow behavior of the MG is revealed by computational fluid dynamics and density funtional theory simulation. Also, we suggest the formation mechanism of the Ag electrodes, and demonstrate the criteria of MG for higher electrode performance. Consequently, when Al85Ni5Y8Co2 MG is added in the Ag electrodes, cell efficiency is enhanced up to 20.30% which is the highest efficiency reported so far for screen-printed interdigitated back contact solar cells. These results show the possibility for the replacement of electroplating process to screen-printing process.

Highly Conductive Aromatic Functionalized Multi-Walled Carbon Nanotube for Inkjet Printable High Performance Supercapacitor Electrodes

Ujjain, Sanjeev K.; Bhatia, Rohit; Ahuja, Preety; Attri, Pankaj
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 08/07/2015 EN
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35.76%
We report the functionalization of multiwalled carbon nanotubes (MWCNT) via the 1,3-dipolar [3+2] cycloaddition of aromatic azides, which resulted in a detangled CNT as shown by transmission electron microscopy (TEM). Carboxylic moieties (-COOH) on aromatic azide result in highly stable aqueous dispersion (max. conc. ~ 10 mg/mL H2O), making the suitable for inkjet printing. Printed patterns on polyethylene terephthalate (PET) flexible substrate exhibit low sheet resistivity ~65 Ω. cm, which is attributed to enhanced conductivity. Fabricated Supercapacitors (SC) assembled using these printed substrates exhibit good electrochemical performance in organic as well as aqueous electrolytes. High energy and power density (57.8 Wh/kg and 0.85 kW/kg) in 1M H2SO4 aqueous electrolyte demonstrate the excellent performance of the proposed supercapacitor. Capacitive retention varies from ~85–94% with columbic efficiency ~95% after 1000 charge/discharge cycles in different electrolytes, demonstrating the excellent potential of the device for futuristic power applications.

Conformal Pad-Printing Electrically Conductive Composites onto Thermoplastic Hemispheres: Toward Sustainable Fabrication of 3-Cents Volumetric Electrically Small Antennas

Wu, Haoyi; Chiang, Sum Wai; Yang, Cheng; Lin, Ziyin; Liu, Jingping; Moon, Kyoung-Sik; Kang, Feiyu; Li, Bo; Wong, Ching Ping
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 28/08/2015 EN
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35.86%
Electrically small antennas (ESAs) are becoming one of the key components in the compact wireless devices for telecommunications, defence, and aerospace systems, especially for the spherical one whose geometric layout is more closely approaching Chu’s limit, thus yielding significant bandwidth improvements relative to the linear and planar counterparts. Yet broad applications of the volumetric ESAs are still hindered since the low cost fabrication has remained a tremendous challenge. Here we report a state-of-the-art technology to transfer electrically conductive composites (ECCs) from a planar mould to a volumetric thermoplastic substrate by using pad-printing technology without pattern distortion, benefit from the excellent properties of the ECCs as well as the printing-calibration method that we developed. The antenna samples prepared in this way meet the stringent requirement of an ESA (ka is as low as 0.32 and the antenna efficiency is as high as 57%), suggesting that volumetric electronic components i.e. the antennas can be produced in such a simple, green, and cost-effective way. This work can be of interest for the development of studies on green and high performance wireless communication devices.

Ternary Blend Ink Formulations for Fabricating Organic Solar Cells via Inkjet Printing

KRAFT, THOMAS M
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
35.83%
Two approaches were followed to achieve increased control over properties of the photo-active layer (PAL) in solution processed polymer solar cells (PSCs). This was accomplished by either (1) the addition of functionalized single-walled carbon nanotubes (SWCNTs) to improve the charge transport properties of the device or (2) the realization of dual donor polymer ternary blends to achieve colour-tuned devices. In the first component of the study, P3HT:PC61BM blends were doped with SWCNTs with the ambition to improve the morphology and charge transport within the PAL. The SWCNTs were functionalized with alkyl chains to increase their dispersive properties in solution, increase their interaction with the P3HT polymer matrix, and to disrupt the metallic characteristic of the tubes, which ensures that the incorporated SWCNTs are primarily semi-conducting. P3HT:PCBM:CNT composite films were characterized and prepared for use as the photoactive layer within the inverted solar cell. The CNT doping acts to increase order within the active layer and improve the active layer’s charge transport properties (conductivity) as well as showed some promise to increase the stability of the device. The goal is that improved charge transport will allow high level polymer solar cell (PSC) performance as the active layer thickness and area are increased...

Macroscopic and high-throughput printing of aligned nanostructured polymer semiconductors for MHz large-area electronics

Bucella, Sadir G.; Luzio, Alessandro; Gann, Eliot; Thomsen, Lars; McNeill, Christopher R.; Pace, Giuseppina; Perinot, Andrea; Chen, Zhihua; Facchetti, Antonio; Caironi, Mario
Fonte: Nature Pub. Group Publicador: Nature Pub. Group
Tipo: Artigo de Revista Científica
Publicado em 25/09/2015 EN
Relevância na Pesquisa
45.81%
High-mobility semiconducting polymers offer the opportunity to develop flexible and large-area electronics for several applications, including wearable, portable and distributed sensors, monitoring and actuating devices. An enabler of this technology is a scalable printing process achieving uniform electrical performances over large area. As opposed to the deposition of highly crystalline films, orientational alignment of polymer chains, albeit commonly achieved by non-scalable/slow bulk alignment schemes, is a more robust approach towards large-area electronics. By combining pre-aggregating solvents for formulating the semiconductor and by adopting a room temperature wired bar-coating technique, here we demonstrate the fast deposition of submonolayers and nanostructured films of a model electron-transporting polymer. Our approach enables directional self-assembling of polymer chains exhibiting large transport anisotropy and a mobility up to 6.4 cm2 V−1 s−1, allowing very simple device architectures to operate at 3.3 MHz. Thus, the proposed deposition strategy is exceptionally promising for mass manufacturing of high-performance polymer circuits.

A job profile oriented scheduling architecture for improving the throughput of industrial printing environments

DO CARMO, ANDRIELE BUSATTO; RAEDER, MATEUS; NUNES, THIAGO; KOLBERG, MARIANA; Luiz Gustavo Leão Fernandes
Fonte: Pontifícia Universidade Católica do Rio Grande do Sul Publicador: Pontifícia Universidade Católica do Rio Grande do Sul
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
45.86%

Synthesis, Contact Printing, and Device Characterization of Ni-Catalyzed, Crystalline InAs Nanowires

Ford, Alexandra C.; Ho, Johnny C.; Fan, Zhiyong; Ergen, Onur; Altoe, Virginia; Aloni, Shaul; Razavi, Haleh; Javey, Ali
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 07/07/2008
Relevância na Pesquisa
35.9%
InAs nanowires have been actively explored as the channel material for high performance transistors owing to their high electron mobility and ease of ohmic metal contact formation. The catalytic growth of non-epitaxial InAs nanowires, however, has often relied on the use of Au colloids which is non-CMOS compatible. Here, we demonstrate the successful synthesis of high yield of crystalline InAs nanowires with high yield and tunable diameters by using Ni nanoparticles as the catalyst material on amorphous SiO2 substrates. The nanowires show superb electrical properties with field-effect electron mobility ~2,700 cm2/Vs and ION/IOFF >103. The uniformity and purity of the grown InAs nanowires are further demonstrated by large-scale assembly of parallel arrays of nanowires on substrates via the contact printing process that enables high performance, printable transistors, capable of delivering 5-10 mA ON currents (~400 nanowires).; Comment: 21 pages, 5 figures included, all in .docx format. Nano Research (In Press)

Fluid characterisation and drop impact in inkjet printing for organic semiconductor devices

Jung, Sungjune
Fonte: University of Cambridge; Department of Engineering Publicador: University of Cambridge; Department of Engineering
Tipo: Thesis; doctoral; PhD
EN
Relevância na Pesquisa
35.99%
An inkjet printer can deposit a very small volume of liquid with high positional accuracy, high speed and low cost. As a maskless, non-contact additive patterning method, inkjet printing technology is increasingly being explored as an alternative to lithography, etching and vapour deposition processes to pattern electrical conductors and thin films with applications in printed electronic devices. The functional inks used in many of the applications involve non-linear viscoelasticity and their behaviours in the context of inkjet printing have not been fully understood. This thesis aims to characterise Newtonian and non-Newtonian properties of inkjet fluids and identify the key parameters affecting drop impact and spreading processes. Various fluid characterisation techniques such as the filament stretching rheometer and piezoelectric axial vibrator are explored. We propose an experimental method to assess the jettability of non-Newtonian inkjet fluids, without using an inkjet print head. The oblique collision of two continuous liquid jets leads to the formation of a thin oval liquid sheet bounded by a thicker rim which disintegrates into ligaments and droplets. Under certain conditions the flow structure exhibits a remarkably symmetrical ?fishbone? pattern composed of a regular succession of longitudinal ligaments and droplets. Good correlation was found between the maximum included angle of the fishbone pattern and the maximum ligament length in the jetting experiments...

Investigation of High Resolution 3D Rodent-morphic Dosimetry, and Cost-Effective Optical-CT using Fresnel Lenses

Bache, Steven
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Tese de Doutorado
Publicado em //2014
Relevância na Pesquisa
35.84%

Micro-irradiators enable exploration of the efficacy of novel radiation treatment approaches by providing the capability to reproduce realistic treatment delivery in small animal models. An approach of current topical interest is hypofractionated stereotactic body radiation therapy (SBRT), and the study of associated tumor and normal tissue radio-biology. Rodent SBRT is extremely challenging, requiring the precise delivery of radiation beams on the order of several millimeters. At present there are no methods to comprehensively verify these delivery techniques due to the requirements for ultra-high resolution and ability to measure the dose in 3 dimensions (3D).

This work introduces a potential solution to the rodent SBRT verification challenge: radiochromic rodent-morphic 3D dosimeters compatible with ultra-high resolution optical computed tomography (optical-CT) dose read-out. Rodent-morphic dosimeters were produced by 3D-printing molds of rodent anatomy directly from X-ray CT data, and using these molds to create tissue-equivalent phantoms both with and without high-Z spinal inserts for cone-beam CT targeting. Feasibility was evaluated through a series of irradiations, including a 180-degree spinal arc treatment. Dose distributions were measured in high-resolution (0.5mm isotropic voxels) with an in-house built optical-CT system...

High-performance architecture for color error diffusion

Brown, Christopher; Savakis, Andreas
Fonte: The International Society for Optical Engineering (SPIE) Publicador: The International Society for Optical Engineering (SPIE)
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
45.83%
Error diffusion is one of the most widely used algorithms for halftoning gray scale and color images. It works by distributing the thresholding error of each pixel to unprocessed neighboring pixels, while maintaining the average value of the image. Error diffusion results in inter-pixel data dependencies that prohibit a simplistic data pipelining processing approach and increase the memory requirements of the system. In this paper, we present a multiprocessing approach to overcome these difficulties, which results in a novel architecture for high performance hardware implementation of error diffusion algorithms. The proposed architecture is scalable, flexible, cost effective, and may be adopted for processing gray scale or color images. The key idea in this approach is to simultaneously process pixels in separate rows and columns in a diagonal arrangement, so that data dependencies across processing elements are avoided. The processor was realized using an FPGA implementation and may be used for real-time image rendering in high-speed scanning or printing. The entire system runs at the input clock rate, allowing the performance to scale linearly with the clock rate. Higher data rate applications required by future applications will automatically be supported using more advanced high-speed FPGA technologies.; "High-performance architecture for color error diffusion...

A Study of the relative importance of plate halftone dot size and halftone creation method on the reproduction of highlight tonal regions for flexography

Sam, Jonathan
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
35.97%
The flexographic printing process has historically had difficulty printing vignettes and highlights. In comparison to offset lithography and gravure, flexography suffers from dark highlights, dirty colors, less "crispness" and an inability to print full-range vignettes. The predominant belief by the printers and manufacturers in the flexographic industry is that these difficulties arise from the excessive dot gain inherent to the process. One major cause of dot gain in flexography is believed to be the halftone dot structure on the printing plate. Many methods have been developed around modification of the traditional plate creation methods with the goal of obtaining an optimal dot structure for minimizing dot gain on press. These methods have included the use of alternate light sources, exposure time modifications, FM screening, direct-to-plate technology and others. One explanation that hasn't been explored is that the printed dot size is purely a function of the ability to produce a small dot on the printing plate. This work performed a series of pressruns using a selection of the popular halftone dot creation technologies to determine whether it is merely the ability to put the smallest dot on the plate that provides optimum print quality. Additionally...

Effects of exposure on the printing characteristics of the association product process

Davis, Claude David
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
35.97%
The investigation examined the printing characteristics of the association product plate, a continuous tone lithographic process which utilizes a synthetic, light-sensitive coating variably ink-receptive according to the degree of exposure it receives. The methodology was designed to determine (1) the printing range of the plate, (2) the effective sensitivity of the coating to varying amounts of exposure within this range, and (3) the degree to which adherence to ideal tone reproduction could be achieved through systematic variation of exposure. The plate is not commercially available, therefore it was necessary to consult patent literature and prior research to obtain details of the coating composition and plate manufacture. A number of pre-trial tests were conducted to optimize the manufacturing process and achieve a desirable balance of coating resiliency and printability. After optimizing plate manufacture, equal-interval continuous tone gray scales were printed on a conventional lithographic press to determine the printing characteristics of the plate. The characteristic curves which were generated by plotting printed densities against negative densities revealed low highlight contrast and high midtone and shadow contrast within a relatively narrow log exposure range of .75-1.10. Faulty tone reproduction can often be corrected by modifying the contrast gradients of the film negative(s) used for plate exposure. In halftone lithography...

An Investigation into papers for digital printing

Evans, Mary Anne; LeMaire, Bernice
Fonte: Printing Industry Research Center at RIT Publicador: Printing Industry Research Center at RIT
Tipo: Monograph Formato: 20674437 bytes; application/pdf
EN_US
Relevância na Pesquisa
46.04%
This study is designed to identify constraints and potential solutions for improved performance and quality of digitally printed papers. The targeted market segment is high-end digital production in the U.S. In the first phase a survey of print providers has been conducted, the sample drawn from the network of printing companies currently engaged with Printing Industry Center research activities. The second phase will be to follow up observations from the survey with a case study approach, working with both print providers and with digital press manufacturers. In order to understand the characteristics of this digital printing market segment, a demographic study of the respondent group was conducted as part of the survey. This was followed by an exploration of the considerations and paper characteristics that are involved in the paper grade selection decision. The role that paper characteristics and press requirements play in production efficiency and document quality was investigated. The change in paper costs to printers over the last few years was also explored.Specific research objectives included: identifying the paper grades commonly used for the market segment of production digital printing, identifying the number of brands used and the nature of printing companies’ relationships to suppliers...

Studies of the properties of poly (ethylene oxide) as a substitute for gum arabic in the fountain solution

Chongpipatanasook, Orapan
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
35.89%
Poly (ethylene oxide) is a polymer of ethylene oxide. It is one of the classes of synthetic water soluble resins which are commercially available. The properties of poly (ethylene oxide) as a desensitizer in the fountain solution were studied. The solution of this resin was compared to gum arabic solution. The investigation included the study of the physical properties of the solutions at different concentrations as well as press performance. Comparisons were made as to wettability, viscosity, surface tension, the ability to clean the plate, the resistance to scum, printing sharpness, resolution, and the plate-press characteristic curve. The experiments were made under controlled conditions; the only variable being one ingredient of the fountain solution. The properties of each solution were discussed and reported. The concentration of poly (ethylene oxide) necessary was determined. Most of the results were statistically analyzed by the two factors analysis of variance. The properties of poly (ethylene oxide) as a substitute for gum arabic in the fountain solution varied. Poly (ethylene oxide) is comparable in regard to the ability to clean the plate, resistance to scum, and printing sharpness. The gum arabic solution gives better resolution. The plate-press characteristic curves appear to be alike and almost superimpose on each other. The advantage of poly (ethylene oxide) is its high resistance to bacterial attack.

A cost and performance analysis of the three electronic communication systems currently in use in the printing and publishing industry

Richards, Susan
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
36.05%
This study describes and evaluates the three electronic graphic communication systems presently used by the printing and publishing industry. The author has selected generic system names for each of the systems. These are: System 1: Page Facsimile System 2: Character-Encoding System 3: Pixel Density-Map Page Facsimile systems are primarily used by newspaper publishers. The Character-Encoding and Pixel Density-Map systems are alternate methods primarily used by newsweekly magazine publishers. All three communication systems offer the user a means of transmitting editorial, and in some cases advertising pages, to remote printing facilities for manufacturing and distribution. Each electronic graphic communication system is investigated in depth. The study provides specific information for the potential user, and the current user. The problem for the user is how to best match the communication system, i.e. how the system operates, the cost and performance of that system, with the user's requirement for transmitting graphic information. Based on the full evaluation of each of the systems in the study, the author concludes the following: System 1: Page Facsimile The Page Facsimile system is relatively simple for the user to install and operate. However...

Reasons for the low usage of scheduling software and the difference in production performance between users and nonusers of scheduling software from a lean manufacturing perspective

Yveborg, Sandra
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
36.07%
It is more important than ever for printers to improve efficiency and productivity, and the means for doing so are available. Computer-assisted scheduling is one method that is claimed to increase throughput speed and reduce costs, among other benefits. Recently, scheduling applications have started to increase in popularity, and many management information systems (MISs) have built-in scheduling features. However, only 15% of the companies that own scheduling software utilize it. The first part of this research project seeks to determine the reasons for the low usage. Another way to increase efficiency is through Lean manufacturing, a strategy for eliminating non-value-added activities, such as defects, excess inventory, and overproduction. Lean manufacturing and computer-assisted scheduling share many of the same objectives. The second part of the research project seeks to determine whether or not there is a difference in production performance between users and nonusers of scheduling software from a lean manufacturing perspective. The analysis is based on data collected through an email questionnaire from 60 commercial printing companies in the U.S. It was found that the surveyed companies who own scheduling software but do not use it...

An Investigation of the performance of gray-component replacement

Tolmie, Melissa Berry
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
35.89%
Members of the graphic arts industries are slowly becoming aware of undercolor reduction techniques used in the attempt to help stabilize high speed wet printing. Undercolor removal is a color correction method which follows this line of thought as it reduces the amount of ink coverage by the process-color inks and increases ink coverage of the black printer in the darker neutral areas of a reproduction. The advantages realized by this technique are carried even further with gray-component replacement (GCR) . GCR removes the process color inks that make up a dark tone and replaces them with black ink in both neutral and color regions of a reproduction. This separation method provides technical and cost benefits to the printer. An investigation of this reproduction technique forms the basis of this research project. A comparison was made between the quality performance of gray-component replacement techniques and the traditional four-color reproduction method. It was found through visual subjective testing, while not all the tone reproduction criteria favored the traditional four-color reproduction method, color and print contrast were affected by the use of gray-component replacement.