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Design and Evaluation of a Novel Conveyor Utilizing a Screw Mechanism to Move Objects With Integrated Racks / Design och utvärdering av en ny transportör som använder en skruvmekanism för att flytta föremål med integrerade kuggstängerNilsson, Måns, Nordqvist, Mathias Nils Edvin January 2021 (has links)
Intralogistics, or material handling, traditionally use roller or chain conveyors to moveo bjects and goods in factories and warehouses. One negative aspect of the traditional types of conveyors is that they are expensive, as they are comprised of many moving parts. This thesis proposes a novel type of conveyor solution in which a transportation fixture with an integrated open thread slides on L-shaped profiles and is propelled forward by a screw. A potential obstacle to the usefulness of such a conveyor is that a screw has innately low efficiency due to the mechanics of screws compared to the principle of rolling that is employed in a roller or chain conveyor. This thesis investigates the functionality and efficiency of the proposed conveyor, or more particularly the core functionality, which is the screw and thread mechanism. A test rig was designed and built, in which experiments were carried out. In the experiments, the material, manufacturing technology, and helix angle of the screw and thread, and the speed were varied. The influence on torque, power demand, and efficiency among other parameters were measured and evaluated. Additionally, a method for automatic thread meshing is presented and testing of it was carried out, which showed reliability with and without positional feedback, which gives the conveyor more use cases. It was found that the efficiency of the screw and thread mechanism was higher for screws with a higher lead, steel screws with a diameter of 50 mm exhibited an efficiency of 31% ± 4.5 % with a lead of 32 mm but only 8.7% ± 1.6 % with a lead of 8 mm. 3D printed plastic screws had slightly lower but similar early life efficiency as steel screws, but seized or wore down when tested in an accelerated lifetime experiment. Because a high screw lead is favorable, and because of the size and geometry constraints of such a conveyor (discussed in the conclusion of the report), a direct drive motoris not suitable, and instead a motor and gearbox combination is recommended. The conveyor shows promise as an alternative solution to traditional conveyors in low load applications. / Intralogistik, eller materialhantering, använder traditionellt rull- eller kedjetransportörer för att flytta gods i fabriker och lager. En negativ aspekt med dessa traditionella transportörer är att de är dyra, då de består av ett stort antal rörliga delar. Detta examensarbete föreslår en ny typ av transportör i vilken en transportfixtur med en inbyggd kuggstång glider på L-formade profiler and drivs framåt av en skruv. Ett potentiellt hinder för denna typ av transportörs användbarhet är att en skruv naturligt har låg verkningsgrad på grund av skruvens mekanik i jämförelse med principen av rullning som används av rull- och kedjetransportörer. Detta examensarbete undersöker funktionaliteten och verkningsgraden av den föreslagna transportören, mer specifikt kärnfunktionaliten som är en skruv- och gängmekanism. En testrigg designades och byggdes, i vilken experiment utfördes. I experimenten varierades materialet och spiralvinkeln av skruven och gängan, samt hastigheten. Vridmomentet, effekten, verkningsgraden och andra parametrar mättes och utvärderades. Dessutom presenteras en metod för automatiskt gängingrepp som även testades, som visade sig vara tillförlitligt både med och utan positionsåterkoppling, vilket ger skruvtransportören fler användningsområden. Resultaten visade att verkningsgraden av skruv och gängmekanismen var högre för skruvar med högre spiralvinkel. Stålskruvar med en diameter på 50 mm visade på en verkningsgrad om 31% ± 4.5 % med en stigning på 32 mm men endast 8.7% ± 1.6 % med en stigning på 8 mm. 3D-Printade plastskruvar hade något lägre men liknande verkningsgrad som stålskruvar i början av sin livslängd, men skar fast eller nöttes ned när de testades i ett långtidsexperiment. Eftersom hög stigning på skruven är fördelaktigt och på grund av de geometriska begränsningar av en sådan transportör (diskuteras i slutsatsen av rapporten), är det inte lämpligt att driva skruven direkt från en elmotor, utan istället rekommenderas en motorväxellådekombination. Transportören verkar lovande som ett alternativ till traditionella transportörer i applikationer med låg last.
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Semiflexible biopolymers in bundled arrangementsSchnauß, Jörg, Händler, Tina, Käs, Josef A. 04 August 2016 (has links) (PDF)
Bundles and networks of semiflexible biopolymers are key elements in cells, lending them mechanical integrity while also enabling dynamic functions. Networks have been the subject of many studies, revealing a variety of fundamental characteristics often determined via bulk measurements. Although bundles are equally important in biological systems, they have garnered much less scientific attention since they have to be probed on the mesoscopic scale. Here, we review theoretical as well as experimental approaches, which mainly employ the naturally occurring biopolymer actin, to highlight the principles behind these structures on the single bundle level.
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大型企業資訊安全實務研究 / A Research into Information Security Case Study of Large-Scale Firms金慶柏, Chin,Robert CP Unknown Date (has links)
本研究主要在探討大型企業的資訊安全案例。在二十一世紀的今天,資訊系統及電腦資產對組織的成功更加重要,所以務必防止它們遭受遺失、竄改或毀滅的風險。資訊安全是保護資料、資訊遭受意外或有意的誤用的一種過程,不論是被組織內或組織外的人,包括員工、外包的顧問或網路上的駭客。資訊安全是組織中很策略的一環,不光是也不應是資訊部門一己的責任。
依據Datamonitor的估計,美國企業一年在資訊安全漏洞上至少損失美金一百五十億元。根據電腦安全學院(Computer Security Institute, CSI)及聯邦調查局(Federal Bureau of Intelligence, FBI)2004年的問卷調查顯示百分之四十九的企業曾發生個人電腦失竊的案例。依據IronPort的估計,一年前每年約有三百億封垃圾郵件,現在則激增至五百五十億封垃圾郵件。時至今日,對於資訊安全的主要威脅不是來自於組織外的駭客、病毒或蠕蟲,而是組織內的個人。不論組織內的個人是有意或無意地違反資訊安全的政策和規定,其後果可能相當嚴重,小至組織形象受損、業務損失,大至官司纏身或巨額罰款。
根據紐約時報2006年的報導:臺灣的高科技公司佔有全球半導體晶圓專工產業百分之七十的市佔率,百分之四十的半導體封裝市場,百分之五十的半導體測試市場,百分之八十的電腦主機板市場,百分之七十二的筆記本電腦代工市場,百分之六十八的LCD螢幕市場。我們如何繼續保持在全球市場上的領先地位?我們仍然得繼續在研究發展、生產製造及全球運籌上加碼投資。然而,在全球經濟之下,如何透過執行一套安全的、全球的及穩定的資訊網路及基礎架構以提供客戶更好的服務更是必要的。
對每一位資訊長或資安長而言,資訊安全永遠是他最關心的前三大議題之一。資訊安全當然是說比做容易,正確導入與永續執行才是根本。花錢購買資訊安全設備是相對簡單的。知道要保護什麼,如何保護以及要控制什麼就沒有那麼簡單了。在真實的商業世界裡,基於家醜不外揚,鮮有公司願意分享或公佈它資訊安全上的弱點及缺點。本論文的主要目的有二:一是研究業界最新的資訊安全標準及資訊安全供應商的看法,例如:
1. 國際標準組織(International Standard Organization, ISO)17799。
2. 英國標準組織(British Standard Institute, BS)7799。
3. 國際商業機器股份有限公司(International Business Machines, IBM)的資訊安全計劃。
4. 惠普股份有限公司(HP)及Information Security System公司的資訊安全稽核機制。
5. 微軟股份有限公司(Microsoft)。
二是提供一些真實的成功案例以提供給其他有興趣的組織作為參考。從結論發現,我們可藉由改善核心業務流程,去建造新的資訊安全系統,去運營一個可長治久安的實體與虛擬的環境,並強化公司的知識管理及傳承 / In the twenty-first century, information system and computing assets are more critical to organization’s success, and as a result, must be protected from loss, modification or destruction. Information security is the process of protecting data / information from accidental or intentional misuse by person inside or outside of an organization, including employee, consultants, and hackers. Information security is a strategic part of an organization, not just the issue of Management Information System, MIS, or Information Technology, IT, department.
According to “Datamonitor”, US$ 15 billion, at least, cost of information security breaches to United States businesses in one year. From the survey of Computer Security Institute, CSI, and Federal Bureau of Intelligence, FBI, in 2004, 49% of companies experienced notebook Personal Computer theft. According to IronPort, there are 55 billion spam e-mail per year right now, compared with 30 billion spam e-mail yearly. Today, the largest threat to information security is not the typical hacker, virus or worm, but the corporate insider. Whether insiders violate data security policies in advertently or with maliciously, the result can expose the company to public embarrassment, lost business, costly lawsuit, and regulatory fines.
Taiwanese high-technology companies have 70% market share of worldwide semiconductor foundry business, 40% share of semiconductor package segment, 50% share of semiconductor testing, 80% of computer motherboard, 72% share of notebook PC, 68% of LCD monitor --- New York Times, 2006. How can we keep maintaining the leading positions around the globe? To invest in R&D, manufacturing, and global logistics is key. However, how to implement a secure, global and reliable IT network and infrastructure to server customers better is a must under current global economy.
To every Chief Information Officer, CIO, or Chief Security Officer, CSO, Information security is always one of the top 3 to-do list. Information security is easy to talk about. But, implementations and executions are where talk must turn into action. Purchasing security device is easy. Knowing how and what to protect ad what controls to put in place is a bit more difficult. In the real commercial world, no one or company would like to share or release its weakness to the public. The objective of this thesis is to study most updated information security industry standard and information security suppliers’ view, like:
1. International Standard Organization, ISO, 17799.
2. British Standard Institute’s BS 7799.
3. IBM’s Information Security Program, ISP.
4. HP & Information Security Systems’ Information Security Audit Mechanism, ISAM.
5. Microsoft
Also to provide a real successful case / framework for other companies to ensure a consistent, enterprise-wide information security focus is maintained across organization boundaries. In conclusion, this information security study proposes to transfer core business process, to build information security new applications, to run a scalable, available, secure environment, and to leverage firms’ knowledge and information.
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Phase transitions in novel superfluids and systems with correlated disorderMeier, Hannes January 2015 (has links)
Condensed matter systems undergoing phase transitions rarely allow exact solutions. The presence of disorder renders the situation even worse but collective Monte Carlo methods and parallel algorithms allow numerical descriptions. This thesis considers classical phase transitions in disordered spin systems in general and in effective models of superfluids with disorder and novel interactions in particular. Quantum phase transitions are considered via a quantum to classical mapping. Central questions are if the presence of defects changes universal properties and what qualitative implications follow for experiments. Common to the cases considered is that the disorder maps out correlated structures. All results are obtained using large-scale Monte Carlo simulations of effective models capturing the relevant degrees of freedom at the transition. Considering a model system for superflow aided by a defect network, we find that the onset properties are significantly altered compared to the $\lambda$-transition in $^{4}$He. This has qualitative implications on expected experimental signatures in a defect supersolid scenario. For the Bose glass to superfluid quantum phase transition in 2D we determine the quantum correlation time by an anisotropic finite size scaling approach. Without a priori assumptions on critical parameters, we find the critical exponent $z=1.8 \pm 0.05$ contradicting the long standing result $z=d$. Using a 3D effective model for multi-band type-1.5 superconductors we find that these systems possibly feature a strong first order vortex-driven phase transition. Despite its short-range nature details of the interaction are shown to play an important role. Phase transitions in disordered spin models exposed to correlated defect structures obtained via rapid quenches of critical loop and spin models are investigated. On long length scales the correlations are shown to decay algebraically. The decay exponents are expressed through known critical exponents of the disorder generating models. For cases where the disorder correlations imply the existence of a new long-range-disorder fixed point we determine the critical exponents of the disordered systems via finite size scaling methods of Monte Carlo data and find good agreement with theoretical expectations. / <p>QC 20150306</p>
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Produção de forragem hidropônica em solução orgânica / Production of hydroponic fodder in organic solutionMorselli, Larri Antônio 07 December 2010 (has links)
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Previous issue date: 2010-12-07 / Hydroponic forage production using vermicompost obtained from
manure of animals is a way to solve problems related to the production costs,
lack of water in Summer and cold Winter. The adoption of this practice can be
an alternative in the production of milk, allowing the inclusion of small farmer
into an increasing consumer market of organic products. In this sense two
experiments were conducted in high tunnel greenhouse type at the Campo
Didático e Experimental of Departamento de Fitotecnia/Faculdade de
Agronomia Eliseu Maciel/Universidade Federal de Pelotas/RS/UFPEL , in order
to evaluate the yield and nutritional quality of fodder plants produced in
hydroponically with organic solution. Randomized blocks experimental design
was used for both experiments, with eight treatments (two crops two
recommend base solutions and two earth-worm compost) and five replications
totalizing 40 plots. The following variables where evaluated: plant height, fresh
and dry mass at 14 days after sowing and the qualitative variables: crude
protein, crude fiber, fiber in acid detergent and neutral detergent, ether extract
and ashes. The evaluated crops were: wheat (Triticum aestivum L.) and black
oats (Avena strigosa Schreb) in the first experiment and maize (Zea mayz L.)
and millet (Pennisetum glaucum L.) in the second experiment. Eisenia foetida
earth-worm composts in liquid form, obtained from bovine and pig manure,
according two nitrogen recommendations 190.6 and 105.9 mg L-1 of N
respectively, by Santos et al. (2003) and Neves (2001) - were used as fertilizer
sources to formulate organic nutrient solutions. There was no significant
difference between wheat and black oats in relation to plant height, fresh mass,
crude protein and ashes. Concerning to dry mass and ether extract oats
presented higher values, while wheat presented higher crude fiber, fiber in
neutral detergent and fiber in acid detergent than oats. Bovine and pig manure
earth-worm composts as well as Santos and Neves base solutions did not show
significant differences for both crops. At the second experiment maize and millet
crops presented no differences for crude fiber, neutral detergent fiber and acid
detergent fiber. Maize presented much higher plant height, fresh and dry mass
values, while millet presented higher crude protein, ether extract and ashes.
The obtained results point out that it is possible to use both earth-worm
composts as well as the two base solutions without loss in yield quality and
bromatological composition for wheat, oats and maize cultivation. Among the
fodder crops, the decision will follow the farmer choice or animals demand at
the moment. / A produção de forragem hidropônica utilizando vermicomposto produzido
a partir do esterco dos próprios animais é uma maneira de minimizar os
problemas relacionados aos custos de produção, da falta de água no verão e
das baixas temperaturas do inverno. A adoção desta prática pode ser uma
alternativa na produção de leite, permitindo a inclusão do pequeno produtor em
um nicho crescente do mercado consumidor que é o de produtos orgânicos.
Nesse sentido, dois experimentos foram realizados em túnel alto, no Campo
Didático e Experimental do Departamento de Fitotecnia da Faculdade de
Agronomia Eliseu Maciel da Universidade Federal de Pelotas (UFPEL) RS,
para avaliar a produtividade e a qualidade nutricional de forragem hidropônica
produzida com solução orgânica no outono. Em ambos os experimentos o
delineamento experimental utilizado foi em blocos ao acaso com oito
tratamentos (duas culturas, duas soluções bases de recomendação e dois
vermicompostos) e cinco repetições, totalizando 40 parcelas. Foram avaliadas
as variáveis altura, fitomassa fresca e seca das plantas aos 14 dias após a
semeadura e as variáveis bromatológicas: proteína bruta, fibra bruta, fibra em
detergente ácido, fibra em detergente neutro, extrato etéreo e cinzas. As
espécies avaliadas foram: trigo (Triticum aestivum L.) e aveia preta (Avena
strigosa Schreb) no primeiro experimento e milho (Zea mayz L.) e milheto
(Pennisetum glaucum L.) no segundo experimento. As soluções nutritivas
usadas nos dois experimentos foram formuladas a partir de vermicompostos,
na forma líquida, obtidos através de esterco bovino e suíno, conforme duas
soluções base de recomendação distinta de nitrogênio: 190,6 e 105,9 mg L-1.
Entre as culturas de trigo e aveia não houve diferença significativa para as
variáveis altura de planta, fitomassa fresca, proteína bruta e cinzas. Nas
variáveis fitomassa seca e extrato etéreo a aveia foi superior enquanto que nas
variáveis fibra bruta, fibra em detergente neutro e fibra em detergente ácido o
trigo foi superior à aveia. Os vermicompostos bovino e suíno, assim como as
soluções bases não diferiram significativamente para as duas culturas
estudadas. No segundo experimento, as culturas de milho e milheto não
diferiram entre si para fibra bruta, fibra em detergente neutro e fibra em
detergente ácido. Para as variáveis altura de plantas, fitomassa fresca e
fitomassa seca, o milho foi superior enquanto que nas variáveis proteína bruta,
extrato etéreo e cinzas o milheto foi superior. Esses resultados indicam que
podemos utilizar os dois vermicompostos assim como as duas soluções bases
de recomendação sem prejuízos na produtividade, qualidade e composição
bromatológica para trigo e aveia. Enquanto que o milho obteve melhor
produtividade o milheto apresentou melhor composição bromatológica.
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Laboratory Investigations on the Applicability of Triphenoxymethanes as a New Class of Viscoelastic Solutions in Chemical Enhanced Oil RecoveryDieterichs, Christin 30 April 2018 (has links) (PDF)
Even in times of renewable energy revolution fossil fuels will play a major role in energy supply, transportation, and chemical industry. Therefore, increasing demand for crude oil will still have to be met in the next decades by developing new oil re-serves. To cope with this challenge, companies and researchers are constantly seeking for new methods to increase the recovery factor of oil fields.
For that reason, many enhanced oil recovery (EOR) methods have been developed and applied in the field. EOR methods alter the physico-chemical conditions inside the reservoir. One possibility to achieve this is to inject an aqueous solution containing special chemicals into the oil-bearing zone. Polymers, for example, increase the viscosity of the injected water and hence improve the displacement of the oil to the production well. The injection of surfactant solutions results in reduced capillary forces, which retain the oil in the pores of the reservoir.
Some surfactants form viscoelastic solutions under certain conditions. The possibil-ity to apply those solutions for enhanced oil recovery has been investigated by some authors in the last years in low salinity brines. Reservoir brines, however, often contain high salt concentrations, which have detrimental effects on the properties of many chemical solutions applied for EOR operations. The Triphenoxymethane derivatives, which were the subject of study in this thesis, form viscoelastic solutions even in highly saline brines. The aim of this thesis was to investigate the efficiency and the mode-of-action of this new class of chemical EOR molecules with respect to oil mobilization in porous media.
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Characterization of early activation of multi-isotypic antibody-producing B lymphocytes in the small intestineWagner, Stephen Douglas 01 January 1999 (has links)
No description available.
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Characterization of early activation of multi-isotypic antibody-producing B lymphocytes in the small intestineWagner, Stephen Douglas 01 January 1999 (has links)
No description available.
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Návrh univerzálního rotačního manipulátoru pro polohování svařenců / Design of universal rotary manipulator for positioning of weldmentsKračmar, Filip January 2019 (has links)
The diploma thesis deals with the design of rotary manipulator for positioning weldments, which could be 5000 mm long and weight 500 kg. The beginning of the thesis presents the research of welding manipulators which could be founded on the market. Three variants of the positioner are proposed in the next section. The resulting variant is optimized using strength analysis in ANSYS software. Furthermore, two variants of drive, by hand drive or electric motor, are presented. The manipulator is interconnected in a single part using a designed frame constructure. Critical points of the manipulator are checked by strength calculation. The final part contains the risk analysis of the proposed manipulator.
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Vyhrnovací dopravník kalového sila / Sediment conveyorFučík, Petr January 2008 (has links)
The subject of this diploma thesis is engineering design of the sediment conveyer. Conveyer is instrumental to total emptying of sediment silo that is situated in a sewage treatment plant. Proposed construction has to fulfill the specified functional requirements and parameters. Parts of solution are also necessary analytical and FEM calculations.
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