71 research outputs found
The density distribution of accreting cosmic filaments as shaped by Kelvin-Helmholtz instability
Cosmic filaments play a crucial role in galaxy evolution transporting gas
from the intergalactic medium into galaxies. However, little is known about the
efficiency of this process and whether the gas is accreted in a homogenous or
clumpy way. Recent observations suggest the presence of broad gas density
distributions in the circumgalactic medium which could be related to the
accretion of filaments. By means of high-resolution hydrodynamical simulations,
we explore here the evolution of cold accreting filaments flowing through the
hot circumgalactic medium (CGM) of high-z galaxies. In particular, we examine
the nonlinear effects of Kelvin-Helmholtz instability (KHI) on the development
of broad gas density distributions and on the formation of cold, dense clumps.
We explore a large parameter space in filament and perturbation properties,
such as, filament Mach number, initial perturbation wavelength, and thickness
of the interface between the filament and the halo. We find that the time
averaged density distribution of the cold gas is qualitatively consistent with
a skewed log-normal probability distribution function (PDF) plus an additional
component in form of a high density tail for high Mach-numbers. Our results
suggest a tight correlation between the accreting velocity and the maximum
densities developing in the filament which is consistent with the variance-Mach
number relation for turbulence. Therefore, cosmological accretion could be a
viable mechanism to produce turbulence and broad gas density distributions
within the CGM.Comment: 12 pages, 14 figures, submitted to MNRAS on April 3rd 201
A life cycle based energy and greenhouse gas emission assessment of C&D waste and container glass recycling in the City of Cape Town
Includes abstract.Includes bibliographical references.The rate at which the world is consuming energy is growing, and with climate change an immediate concern (Stern, 2006), it is incumbent for the global society to find alternate ways of fuelling human activity. Along with greater energy use, global development is also generating ever-greater quantities of waste. Landfill space is becoming increasingly scarce and the assimilative capacity of Earth is reaching its limits. Society's current approach to the production, consumption, and disposal of goods is likely unsustainable. The goal of this research was to assess the difference in cumulative energy demand (CED) and greenhouse gas (GHG) emissions for two waste management options: landfilling and recycling for the two materials of Construction and Demolition (C&D) rubble and container glass in the City of Cape Town (CCT) in order to determine which option has the lower climate impact
Defining Septicemia Incidence and Mortality in South Carolina Through Access to Health Care, Behavioral Health, and Low Socio-Economic Status
This study aims to provide an in-depth view of septicemia mortality and incidence in the state of South Carolina through the lenses of socio-economic factors, access to healthcare, and behavioral health factors. This study was conducted using data from the South Carolina Revenue and Fiscal Affairs Office, utilizing their Hospitalization, Inpatient, Emergency Department, and Outpatient data both separately and combined depending on the data point, along with additional data sources for support (see works cited). We hypothesize that the higher rates of septicemia mortality and incidence in the southeastern United States, as well as in South Carolina in particular, could be associated with rurality, low socio-economic status, and risky behavioral health choices. Bivariate analyses were conducted with SAS 9.4. We found higher rates of septicemia mortality among residents in rural areas, minority residents, and areas with high economic inequality
Der neue RFQ fĂŒr den Hochladungsinjektor der GSI
FĂŒr das Helmholtzzentrum fĂŒr Schwerionenforschung (GSI), in Darmstadt, wurde ein neuer RFQ zur Beschleunigung schwerer Ionen fĂŒr den Hochladungsinjektor (HLI) entwickelt. Dieser RFQ hat den bereits vorhandenen ersetzt und soll, fĂŒr die Anpassung des HLI an die neue 28 GHz-ECR-Ionenquelle, den Duty-cycle von 25 % auf 100 % erhöhen, um superschwere Ionen zu erzeugen und die Experimente mit schweren Ionen zu versorgen. Der RFQ hat die Aufgabe schwere, hochgeladene Ionen von 4 keV/u auf 300 keV/u zu beschleunigen. Wichtige Eigenschaften sind ein hoher Strahlstrom, eine hohe Strahl-Transmission, eine kleine Strahlemittanz und eine geringe transversale Emittanzzunahme. Die Erhöhung der Injektionsenergie von 2,5 keV/u auf 4 keV/u ermöglicht eine Verkleinerung des Konvergenzwinkels. Der Aufbau des 4-Rod-RFQs fĂŒr den HLI ist Thema der vorliegenden Arbeit. Die Auslegung des HLI-RFQs bezieht sich auf ein festgelegtes max. Masse zu LadungsverhĂ€ltnis von A/q = 6, bei einer Betriebsfrequenz von 108,408 MHz. Die Ionen sollen bei einem Strahlstrom von 5 mA von 4 keV/u auf 300 keV/u beschleunigt werden. Durch die spezielle teilchendynamische Auslegung konnte die LĂ€nge des Tanks von vorher 3 m auf jetzt 2 m verkĂŒrzt werden. Dies begĂŒnstigt den CW-Betrieb der Struktur. Durch den CW-Betrieb hat man eine hohe Leistungsaufnahme, dies erfordert eine besondere teilchendynamische und hochfrequenztechnische Auslegung der RFQ-Struktur und eine effiziente KĂŒhlung. Zur Simulation der Hochfrequenzeigenschaften wurde ein Modell des RFQ mit dem Programm Microwave Studio (MWS) erstellt. Die Simulationen ergaben einen nur 2 m langen RFQ mit sehr hoher Transmission > 95%. Nach den entsprechenden Simulationsrechnungen bezĂŒglich der Teilchendynamik und der Hochfrequenzeigenschaften wurde der RFQ aufgebaut. Der zeitaufwĂ€ndige Aufbau lĂ€sst sich in drei Abschnitte einteilen. Die Elektroden wurden prĂ€zise ausgemessen. Danach wurden StĂŒtzen, Elektroden und Tuningplatten an der Bodenplatte montiert und in den Tank eingesetzt. Im Tank wurden die Elektroden justiert, die zuerst auĂerhalb vermessen wurden. Die korrekte Position der Elektroden zur ReferenzflĂ€che wurde berechnet und mit Hilfe eines Faro-Gage im Tank eingemessen. Die maximale Abweichung der Elektrodenposition konnte auf 0,03 mm reduziert werden. Nach der mechanischen Einrichtung folgte die HF-Anpassung des Resonators. Durch das Erhöhen der Tuningplattenpositionen zwischen den StĂŒtzen konnte die Resonanzfrequenz von 90,8 MHz auf 108,4 MHz erhöht werden. Als nĂ€chstes wurde die Spannungsverteilung im Tank gemessen und mit Hilfe der Tuningplatten konnte sie so eingestellt werden, dass die maximale Abweichung zur mittleren Elektrodenspannung bei nur ± 2% liegt. Zur weiteren Hochfrequenzabstimmung wurde die Wirkung zweier Tauchkolben mit einem Durchmesser von 75 mm untersucht. Die Tauchkolben ermöglichen eine Anpassung der Frequenz im Bereich von 1,4 MHz. Sie sollen die möglichen Frequenzverschiebungen durch beispielsweise thermische Effekte, auf Grund des HF-Betriebs, regulieren. FĂŒr die Hochfrequenzabstimmung wurde eine Ankoppelschleife gefertigt und angepasst. Die GĂŒte des Resonators betrug Q0 = 3100, bei einem RP-Wert RP = 100 kΩm, d.h. die zur Versorgung stehende HF-Leistung (50 kW im CW-Betrieb) reicht aus. An der GSI wurde nach dem Transport eine Kontrolle der Elektroden vorgenommen, danach wurde der RFQ erst einzeln, danach als komplette HLI Einheit getestet. Dazu wurden verschiedene Pulsmessungen und Emittanzmessungen mit Argon 7+ und Argon 8+ durchgefĂŒhrt. Bei der ersten Strahlinbetriebnahme wurden die Transmission, die Ionenenergie und die Emittanz mit verschiedenen Ionen gemessen. Die ersten Tests des HLI-RFQ waren sehr vielversprechend. In den Tests war zu sehen, dass die vorgenommenen Arbeiten, wie Justage und HF-Abstimmung der Resonanzstruktur, erfolgreich waren. Danach wurde der Strahlbetrieb mit Calcium, bei einer Leistung von 50 kW, durchgefĂŒhrt. Die gemessene Transmission bei einer Spannung von 43 kV lag bei 70 %. Im Mai 2010 gab es eine 14Stickstoff2+ -Strahlzeit mit einer gepulsten Leistung von N = 90 kW. Danach wurde Anpassungstests mit verschiedenen Schwerionen durchgefĂŒhrt. Im November 2010 wurden neue Tuningplatten mit einer besseren StĂŒtzenkontaktierung sowie einer besseren KĂŒhlung eingebaut. Die Elektroden wurden nach diesen MaĂnahmen auf ± 0,04 mm einjustiert. Die Flatness liegt bei ± 2,1 %, die GĂŒte betrĂ€gt Q0 = 3300. Der RFQ wurde in die Beamline eingebaut und geht im Januar 2011 in Betrieb
UNILAC Upgrades for Coulomb Barrier Energy Experiments
The GSI linear accelerator UNILAC provides heavy ion beams at Coulomb barrier energies for search and study of super heavy elements. Typical cross-sections of 55 fb require beam doses of 1.4·10Âčâč according to a beam time of 117 days. Several upgrades will reduce the beam time to only 16 days. A second injection branch with a 28GHz-MS-ECRIS anticipates a factor of 10 in particle intensity. By a new cw rfq-structure all accelerator tanks are suitable for a duty cycle of at least 50% instead of 25% presently. Due to this, thermal power increase of 19 rf-amplifiers eased by higher ion charge states of the ECRIS is necessary. Finally the UNILAC timing system controlling 50Hz pulse-to-pulse operation of up to six beams differing in ion species and energy has to be modified considering beam diagnostics electronics and pulsable magnets. The front end comprising ECRIS, rfq- and IH-structure is cw suitable and will serve as injector for a new future sc-cw-linac
Experimental Proof of Adjustable Single-Knob Ion Beam Emittance Partitioning
The performance of accelerators profits from phase-space tailoring by coupling of degrees of freedom. Previously applied techniques swap the emittances among the three degrees but the set of available emittances is fixed. In contrast to these emittance exchange scenarios, the emittance transfer scenario presented here allows for arbitrarily changing the set of emittances as long as the product of the emittances is preserved. This Letter is the first experimental demonstration of transverse emittance transfer along an ion beam line. The amount of transfer is chosen by setting just one single magnetic field value. The envelope functions (beta) and slopes (alpha) of the finally uncorrelated and repartitioned beam at the exit of the transfer line do not depend on the amount of transfer.close
Comparative LCA of concrete with recycled aggregates: a circular economy mindset in Europe
[EN] Purpose Construction and demolition waste (C&DW) is the largest waste stream in the European Union (EU) and all over the
world. Proper management of C&DW and recycled materialsÂżincluding the correct handling of hazardous wasteÂżcan have
major benefits in terms of sustainability and the quality of life. The Waste Framework Directive 2008/98/EC aims to have 70% of
C&DW recycled by 2020. However, except for a few EU countries, only about 50% of C&DW is currently being recycled. In the
present research, the environmental impact of concrete with recycled aggregates and with geopolymer mixtures is analysed. The
aim of the present research is to propose a comparative LCA of concrete with recycled aggregates in the context of European
politics.
Methods Life cycle assessment (LCA) methodology is applied using Simapro© software. A cradle to grave analysis is carried
out. The results are analysed based on the database Ecoinvent 3.3 and Impact 2002+.
Results Results show that the concrete with 25% recycled aggregates is the best solution from an environmental point of view.
Furthermore, geopolymer mixtures could be a valid alternative to reduce the phenomenon of Âżglobal warmingÂż; however, the
production of sodium silicate and sodium hydroxide has a great environmental impact.
Conclusions A possible future implementation of the present study is certainly to carry out an overall assessment and to
determine the most cost-effective option among the different competing alternatives through the life cycle cost analysis.Colangelo, F.; GĂłmez-Navarro, T.; Farina, I.; Petrillo, A. (2020). Comparative LCA of concrete with recycled aggregates: a circular economy mindset in Europe. International Journal of Life Cycle Assessment. 25(9):1790-1804. https://doi.org/10.1007/s11367-020-01798-6S17901804259Akhtar A, Sarmah (2018) Construction and demolition waste generation and properties of recycled aggregate concrete: a global perspective. J Cleaner Prod 186:262â281Bare JC, Hofstetter P, Penningtonne DW, Helias A, de Haes U (2000) Midpoints versus endpoints: the sacrifices and benefits. Int J Life Cycle Assess 5(6):319â326Blengini GA, Garbarino E (2010) Resources and waste management in Turin (Italy): the role of recycled aggregates in the sustainable supply mix. J Clean Prod 18(10â11):1021â1030Blengini GA, Garbarino E, Ć olar S, Shields DJ, HĂĄmor T, Vinai R, Agioutantis Z (2012) Life cycle assessment guidelines for the sustainable production and recycling of aggregates: the sustainable aggregates resource management project (SARMa). J Clean Prod 27:177â181Blengini GA, Garbarino E, Bevilacqua P (2017) Sustainability and integration between mineral resources and C&DW management: overview of key issues towards a resource-efficient Europe. Env Eng Man J 16(2):493â502Borghi G, Pantini S, Rigamonti L (2018) Life cycle assessment of non-hazardous construction and demolition waste (CDW) management in Lombardy region (Italy). J Clean Prod 184:815â825Braga AM, Silvestre JD, de Brito J (2017) Compared environmental and economic impact from cradle to gate of concrete with natural and recycled coarse aggregates. J Clean Prod 162:529â543Chen C, Habert G, Bouzidi Y, Jullien A, Ventura A (2010) LCA allocation procedure used as an incitative method for waste recycling: an application to mineral additions in concrete. Res Con Rec 54(12):1231â1240Chen Z, Gu H, Bergman RD, Liang S (2020) Comparative life-cycle assessment of a high-rise mass timber building with an equivalent reinforced concrete alternative using the Athena impact estimator for buildings. Sustainability (Switzerland) 12(11):4708Colangelo F, Cioffi R (2017) Mechanical properties and durability of mortar containing fine fraction of demolition wastes produced by selective demolition in South Italy. Comp Part B: Eng 115:43â50Colangelo F, Petrillo A, Cioffi R, Borrelli C, Forcina A (2018a) Life cycle assessment of recycled concretes: a case study in southern Italy. Sci Total Env 615:1506â1517Colangelo F, Forcina A, Farina I, Petrillo A (2018b) Life cycle assessment (LCA) of different kinds of concrete containing waste for sustainable construction. Buildings 8(5):70Colangelo F, Navarro TG, Petrillo A, Farina I, Cioffi R (2020) Life-cycle impact of concrete with recycled materials. Encyclopedia of Renewable and Sustainable Materials, Volume 5(2020):414â421COM (2012) 433, COMMUNICATION FROM THE COMMISSION TO THE EUROPEAN PARLIAMENT AND THE COUNCIL Strategy for the sustainable competitiveness of the construction sector and its enterprises, http://eur-lex.europa.eu/procedure/EN/201859, Brussels, 31.7.2012, COM(2012) 433 finalCOM (2014) 445, COMMUNICATION FROM THE COMMISSION TO THE EUROPEAN PARLIAMENT AND THE COUNCIL, http://ec.europa.eu/environment/eussd/pdf/SustainableBuildingsCommunication.pdf, Brussels, 1.7.2014 COM(2014) 445 finalDavidovits J (2018) Geopolymers based on natural and synthetic metakaolin a critical review. Ceramic Eng Science Proc 38(3):201â214Di Maria A, Eyckmans J, Van Acker K (2018) Downcycling versus recycling of construction and demolition waste: combining LCA and LCC to support sustainable policy making. Waste Man 75:3â21Directive 2008/98/EC on waste (Waste Framework Directive), http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32008L0098EN 1992-1-1:(2004) Eurocode 2: Design of concrete structures - Part 1â1: General rules and rules for buildingsEstanqueiro B, Dinis Silvestre J, de Brito J, Duarte Pinheiro M (2018) Environmental life cycle assessment of coarse natural and recycled aggregates for concrete. Eur J Env Civ Eng 22(4):429â449Etxeberria M, VĂĄzquez E, MarĂ A, Barra M (2007) Influence of amount of recycled coarse aggregates and production process on properties of recycled aggregate concrete. Cem Conc Res 37(5):735â742EU construction & demolition waste management protocol (2016) BrusselsGĂĄlvez-Martos J-L, Styles D, Schoenberger H, Zeschmar-Lahl B (2018) Construction and demolition waste best management practice in Europe. Res Con Rec 136:166â178Gluth, G.J.G., Arbi, K., Bernal, S.A., Bondar, D., Castel, A., Chithiraputhiran, S., Dehghan, A., Dombrowski-Daube, K., Dubey, A., Ducman, V., Peterson, K., Pipilikaki, P., Valcke, S.L.A., Ye, G., Hajimohammadi, A., van Deventer, J.S.J., 2017. Characterisation of one-part geopolymer binders made from fly ash. Waste Biom Val, 8(1), pp. 225â233Gomes R, Silvestre JD, de Brito J (2020) Environmental, economic and energy life cycle assessment âfrom cradle to cradleâ (3E-C2C) of flat roofs. Journal of Building Engineering 32:101436ISO 14040 (2006) Environmental management life cycle assessment. Principles and Framework. ISO, GenevaISO 14044 (2006) Environmental management. Life cycle assessment. Requirements and Guidelines. ISO, GenevaJafary Nasab T, Monavari SM, Jozi SA, Majedi H (2020) Assessment of carbon footprint in the construction phase of high-rise constructions in Tehran. Int J Environ Sci Technol 17(6):3153â3164Jolliet O, Margni M, Charles R, Humbert S, Payet J, Rebitzer G, Rosenbaum R (2003) Impact 2002+: a new life cycle impact assessment methodology. Int J Life Cycle Assess 8(6):324â333Khan MW, Ali Y, De Felice F, Salman A, Petrillo A (2019) Impact of brick kilns industry on environment and human health in Pakistan. Sci Total Environ 678:383â389Knoeri C, SanyĂ©-Mengual E, Althaus H-J (2013) Comparative LCA of recycled and conventional concrete for structural applications. Int J Life Cycle Assess 18(5):909â918Lu W, Yan H (2011) A framework for understanding waste management studies in construction. Waste Man 31:1252â1260MarinkoviÄ S, Radonjanin V, MaleĆĄev M, IgnjatoviÄ I (2010) Comparative environmental assessment of natural and recycled aggregate concrete. Waste Man 30(11):2255â2264Mercante IT, Bovea MD, Ibåñez-ForĂ©s V, Arena AP (2012) Life cycle assessment of construction and demolition waste management systems: a Spanish case study. Int J Life Cycle Assess 17(2):232â241Pantini S, Giurato M, Rigamonti L (2019) A LCA study to investigate resource-efficient strategies for managing post-consumer gypsum waste in Lombardy region (Italy). Res Con Rec 147:157â168Petrillo A, Cioffi R, De Felice F, Colangelo F, Borrelli C (2016) An environmental evaluation: a comparison between geopolymer and OPC concrete paving blocks manufacturing process in Italy. Env Prog Sus Energy 35(6):1699â1708Provis JL (2017) Alkali-activated cementitious materials and concretes - steps towards standardization, American Concrete Inst, ACI Special Publication 2017-January (SP 320), pp. 444-448Sayagh S, Ventura A, Hoang T, François D (2010) Sensitivity of the LCA allocation procedure for BFS recycled into pavement structures. Res cons rec 54(6):348â358Tangtinthai N, Heidrich O, Manning DAC (2019) Role of policy in managing mined resources for construction in Europe and emerging economies. J Env Man 236:613â621ToĆĄiÄ N, MarinkoviÄ S, DaĆĄiÄ T, StaniÄ M (2015) Multicriteria optimization of natural and recycled aggregate concrete for structural use. J Clean Prod 87(1):766â776Van den Heede P, De Belie N (2012) Environmental impact and life cycle assessment (LCA) of traditional and âgreenâ concretes: literature review and theoretical calculations. Cem Conc Comp 34(4):431â442Vossberg C, Mason-Jones K, Cohen B (2014) An energetic life cycle assessment of C&D waste and container glass recycling in Cape Town, South Africa. Res Con Rec 88:39â49Walling SA, Notman S, Watts P, Govan N, Provis JL (2019) Portland cement based immobilization/destruction of chemical weapon agent degradation products. Industrial Eng Chemistry Res 58(24):10383â10393Wu H, Zuo J, Yuan H, Zillante G, Wang J (2019) A review of performance assessment methods for construction and demolition waste management. Res Cons Recycling 150:104407Zhang C, Hu M, Dong L, Gebremariam A, Mirand-Xicotencatl B, Di Maio F, Tukker A (2019) Eco-efficiency assessment of technological innovations in high-grade concrete recycling. Res Cons Recycling 149:649â66
Management and valorisation of wastes through use in producing alkali-activated cement materials
There is a growing global interest in maximising the re-use and recycling of waste, to minimise the environmental impacts associated with waste treatment and disposal. Use of high-volume wastes in the production of blended or novel cements (including alkali-activated cements) is well known as a key pathway by which these wastes can be re-used. This paper presents a critical overview of the urban, agricultural, mining and industrial wastes that have been identified as potential precursors for the production of alkali-activated cement materials, or that can be effectively stabilised/solidified via alkali activation, to assure their safe disposal. The central aim of this review is to elucidate the potential advantages and pitfalls associated with the application of alkali-activation technology to a wide variety of wastes that have been claimed to be suitable for the production of construction materials. A brief overview of the generation and characteristics of each waste is reported, accompanied by identification of opportunities for the use of alkali-activation technology for their valorisation and/or management
Secure and fault-tolerant DICOM image transfer in medical grid infrastructures
Der gemeinsame Zugriff auf verteilte Datenbanken und die Möglichkeit zur
Kooperation ist fĂŒr die Verbundforschung in der Medizin von zunehmender
Wichtigkeit. Auch spielen bildgebende Verfahren eine immer gröĂere Rolle. Der
Einsatz von 3D- und 4D-Techniken sowie die kontinuierliche Verbesserung der
rÀumlichen und zeitlichen Auflösung stellen immer höhere Anforderungen an die
digitale Bildverarbeitung, vor allem an Speicherplatz und Rechenleistung. Ein
Lösungsansatz zur ErfĂŒllung dieser Anforderungen ist der Einsatz von "Grid-
Infrastrukturen". Dies sind neuartige Strukturen bei der Vernetzung von
Informationssystemen. Dabei werden viele rÀumlich verteilte Rechner zu einem
virtuellen GroĂcomputer zusammengeschlossen. Im Unterschied zu anderen
Forschungsbereichen, in denen diese Technologie bereits seit langem genutzt
wird, erfordert der Einsatz in der Medizin zusĂ€tzliche MaĂnahmen. Dies liegt
unter anderem an den sensiblen Daten, die hohe Sicherheitsanforderungen an
Datentransfer und Kommunikationswege stellen. Die Folge ist, dass der
bisherige de facto Standard zur BildĂŒbertragung, DICOM, allein nicht mehr
ausreicht. Das Ziel dieser Arbeit war es daher, ein möglichst effizientes und
sicheres Verfahren zur DICOM-BildĂŒbertragung in medizinischen Grid-
Infrastrukturen zu entwickeln. Die Grundlage dieses Verfahrens bildet dabei
die durchgÀngige DICOM-Kommunikation nach dem in Grids genutzten
Sicherheitsstandard GSI. GegenĂŒber den bisherigen Verfahren hat dies den
Vorteil, dass die grundlegenden Eigenschaften des DICOM-Protokolls erhalten
bleiben. ZusÀtzlich ermöglichen Software-Router, die herkömmlichen, bereits
verfĂŒgbaren DICOM-GerĂ€te ohne weitere Ănderungen an das Grid anzuschlieĂen.
Ein weiterer, wesentlicher Bestandteil der Arbeit bilden zusÀtzliche
SicherheitsmaĂnahmen zum Schutz patientenbezogener Daten auf den Gridrechnern
sowie zur sicheren Anbindung klinikinterner Bildarchive an die öffentliche
Infrastruktur. Dazu wurden erfolgreich der Einsatz einer neuen, noch nicht im
DICOM-Standard verabschiedeten Pseudonymisierungstechnik untersucht, die den
Zugriff auf einzelne Daten in den Bildern erlaubt, ohne diese auf den fremden
Rechnern entschlĂŒsseln zu mĂŒssen. SchlieĂlich wurden die besonderen Vorteile
dieser drei entwickelten Ăbertragungsverfahren genutzt, um ein modellbasiertes
System zu entwickeln, welches Bildserien automatisiert im Grid ĂŒbertragen
kann. Dabei kann es auf Fehler und SystemausfÀlle im Grid selbstÀndig
reagieren und somit eine erfolgreiche und zuverlĂ€ssige BildĂŒbertragung
garantieren. Damit stellt die Arbeit neue Verfahren vor, die eine
zuverlĂ€ssigere, schnellere und sichere BildĂŒbertragung in Grid-Infrastrukturen
ermöglichen, als die bisher verfĂŒgbaren Methoden es boten. Mithilfe dieser
Verfahren steigt die ZuverlÀssigkeit von Grid-Systemen in der medizinischen
Bildverarbeitung deutlich und ermöglicht so einen Einsatz in der klinischen
Routine.In the medical field, cooperating and sharing distributed databases and
resources is becoming increasingly important. Equally emerging is the role of
digital imaging solutions. Here, however, the advent of modern 3D and 4D
imaging techniques and the continual improvement of both, spacial and
temporary resolution, are making raising demands on the image processing
solutions, especially in terms of computing and storage resources. One
possible solution to satisfy these increased requirements are âgrid-
infrastructuresâ. Grids are modern networks which interconnect many
geographically distributed computers and bundle them to one virtual âsuper-
computerâ. Unlike other areas, where this technology is been widely used, the
medical field requires additional measures due to the sensible data. As a
result, the existing de-facto standard for medical image transfer, DICOM, is
not sufficient anymore. The goal of this work is to develop a highly efficient
and secure DICOM image transfer in medical grid infrastructures. The basis of
this method is a continuous end-to-end DICOM communication according to the
grid security standard GSI. In contrast to existing methods, this transfer has
the advantage of maintaining the fundamental properties of the DICOM protocol.
Furthermore, software routers allow conventional, existing DICOM devices to
connect to the grid without modifications. Another, integral part of this work
are additional security provisions to protect patient-related sensitive data
at the grid nodes and also securely connect clinical picture archives to the
public infrastructure. For this, the use of a new pseudonymization technique
has been tested. The technique allows accessing single data items in the
pictures without having to decrypt the entire image. Finally, based on the
advantages of these three methods a model-based system has been developed
which transfers image series automatically in a grid infrastructure. The
system can react autonomously to errors and outages in the grid and therefore
ensures a successful and reliable image transfer. In combination, the work
presents an original method which allows a faster, more reliable and more
secure image transfer in grids than previously possible. This method
significantly enhances the reliability of grid infrastructures in medical
imaging and thus even allows the operation in the clinical routine
- âŠ