657 research outputs found
Project Omoverhi : a thermal storage solution
One principal energy source that is underutilized in the world today is solar energy. While the United States has tried to make a push for reusable and \u27green\u27 energy sources, these sources are frequently overlooked in developing nations. While the set up costs of solar energy may be expensive due to installation and the high cost of certain parts, the savings over time is well worth the initial cost. In many developing nations large areas of the country are off of the power grid or have inconsistent power. One way to help people living in these areas is by introducing the use of solar power. Unfortunately one major drawback to using solar energy is the difficulty of storing it. While photovoltaic panels can store energy in batteries, they are extremely expensive and inefficient. Using solar collectors that are either manufactured or handmade rather than PV panels can be more than four times as efficient and cost much less. The one negative issue with solar collectors is that they will only work when the sun is out. The 2011 to 2012 Project Omoverhi team\u27s goal was to utilize this energy from solar collectors and store it in a thermal storage container. The stored energy could then be used when direct sunlight was not available. Using paraffin wax as a phase change material because of its melting temperature and excellent storage properties, Project Omoverhi was able to achieve this goal and create an affordable, easy to use system that can be attached to a solar collector. The system was tested to determine if it would enable an incubator to keep a steady temperature that would meet the requirements of a premature infant or successfully hatch chicken eggs. Data collected showed that Project Omoverhi\u27s design is an effective way to store heat and energy from a solar collector so that it can be utilized as needed
OvervĂĽgning af aviĂŚr influenza i vilde fugle i Danmark 2014
OvervĂĽgningen af aviĂŚr influenza (AI) virus i vilde fugle i Danmark i 2014 blev udført i samarbejde mellem VeterinĂŚrinstituttet, Danmarks Tekniske Universitet (DTU-VET), Fødevarestyrelsen (FVST) og Statens Naturhistoriske Museum, Københavns Universitet (SNM) i henhold til â Projektplan vedr. overvĂĽgningen af aviĂŚr influenza i vilde fugle i Danmark i 2014â (bilag 4). OvervĂĽgning af AI pĂĽ EU niveau gĂĽr tilbage til 2002, og Danmark er underlagt EU kommissionens bestemmelser for udformning af overvĂĽgningen, der dog har skiftet gennem ĂĽrene i takt med indhøstede erfaringer. I 2014 blev der udført passiv overvĂĽgning af døde vilde fugle, der blev fundet i naturen. Der blev testet 10 fugle, og ingen af disse var positive for AI virus. Fem blev indsendt af VeterinĂŚrenhederne (FVST), de øvrige var indsendt faldvildt fra private indsamlere. I den aktive overvĂĽgning af levende vilde fugle blev der i alt testet 1012 fugle som 286 pools eller enkeltdyrsprøver af kloaksvabere fra sĂĽ vidt muligt op til 5 fugle af samme art, fundet pĂĽ samme sted og pĂĽ samme tid. I modsĂŚtning til 2011 og 2012, men ligesom i 2013, blev prøverne udtaget fra enkeltdyr og sendt til laboratoriet, hvor de blev poolet inden test. Prøverne blev indsamlet i Jylland, pĂĽ Fyn, Lolland, SjĂŚlland og i Hovedstadsregionen. Frekvensen af positive prøver var højst i Sydvestjylland og meget lav i HovedstadsomrĂĽdet. FVST varetog udtagelse af prøver fra nedlagte ĂŚnder og gĂŚs, der var indleveret pĂĽ vildthĂĽndteringsvirksomhederne Kivan Food (199 fugle), Alpevej Vildtbehandling (150 fugle) og Klosterheden Vildt (150 fugle). SNM udtog prøver fra 502 vildtlevende fugle. Derudover indgik 10 kloaksvaberprøver fra skarver skudt pĂĽ Anholt. Prøverne blev testet for AI virus pĂĽ DTU-VET. I alt 50 (17 %) af prøverne blev fundet positive for AI virus ved PCR. Af de positive prøver var 5 (2 %) LPAI H5 og 3 (1 %) LPAI H7. Andelen og antallet af positive prøver i 2014 var pĂĽ niveau med 2013, men andelen af H5 positive prøver var markant lavere. Til gengĂŚld blev der fundet flere H7 positive prøver end tidligere. AI virus kunne dyrkes fra 13 (5 %) af de 286 prøver, svarende til 26 % af de PCR positive prøver, og pĂĽ niveau med de tidligere ĂĽr. De oftest identificerede danske AI virusisolat-subtyper i perioden 2003-2011 var H3N8, H4N6 og H6N2 fundet i andefugle. Ved subtypning af AI virusisolaterne fra 2014 blev der fundet virus med følgende subtyper: H3N1 (n=4), H3N8 (n=4), H7N3 (n=1), H7N7 (n=1), H6N2(n=1) og H16N3(n=2). Alle isolaterne var fra svømmeĂŚnder, bortset fra H16N3 isolaterne som var fra en mĂĽge og en blishøne. H3N1 og H7N3 subtypekombinationerne er ikke før fundet i Danmark, men de enkelte H og N subtyper er fundet før. Prøverne blev ikke screenet for tilstedevĂŚrelsen af paramyxovirus (PMV), men ved dyrkning i ĂŚg for at isolere AI virus fra AI PCR positive prøver, blev der isoleret PMV isolater fra 10 prøver. Alle PMV isolaterne var fra andefugle (grĂĽand og krikand). To var avirulente PMV1 isolater, 3 var PMV4 og 4 var PMV6, mens et enkelt PMV isolat ikke kunne types nĂŚrmere end til at det ikke var PMV1. Resultatet antyder at andefuglene ofte har paramyxovirus, og ĂŚnder betragtes da ogsĂĽ som naturlig vĂŚrt for de fundne PMV typer. Samme gjorde sig gĂŚldende ved overvĂĽgningen i 2012 og 2013. Mange af prøverne viste sig at indeholde en blanding af flere virus (flere AI virus eller AI og PMV virus). Som et nyt tiltag blev der i 2014 udført subtypning af AI virus pĂĽ primĂŚrmaterialet i udvalgte prøver ved fuldlĂŚngde sekventering af HA og NA generne. Tidligere er der kun screenet for H5/H7 pĂĽ primĂŚrmaterialet og subtypet pĂĽ virusisolater, men da det kun er ca. 10 % af prøverne der kan isoleres virus fra i ĂŚg (virusisolater) vil der vĂŚre mange AI virus positive prøver, hvor subtypen ikke kendes. To og tyve prøver blevet analyseret ved sekvensanalyse pĂĽ primĂŚrmaterialet samt alle 13 AI virusisolater. Følgende subtyper blev pĂĽvist: H2N3, H3N1, H3N3, H3N8, H4N2, H5, H5N2, H6N2, H9N2, H7N3, H7N7, H8N2, H8N4, H9N2, H11, H11N9, H12N5, H16N3. Alle havde som forventet størst lighed med euroasiatiske virus. Fylogenetisk analyse af H5 generne fra 2 prøver viste at disse var nĂŚrt beslĂŚgtede med H5 gener fra virus i prøver fra vilde fugle, der er indsamlet i Danmark i 2012. De er ikke beslĂŚgtet med H5N8 HPAI fundet i Europa i 2014. Fylogenetisk analyse af H7 fra de 3 H7 positive prøver viste, at de var beslĂŚgtet med H7 gener fra europĂŚiske virus. En prøve, H7N7, havde et HA gen, der var meget nĂŚrt beslĂŚgtet med HA fra det H7N7 virus, der var ĂĽrsag til udbrud af LPAI i en slagtekyllingebesĂŚtning i England i januar 2015, hvorimod NA genet var mere forskelligt. Der er altsĂĽ ikke tale om det samme virus, men 2 virus der mĂĽske har deres HA gen fra en fĂŚlles kilde. Analysen viste ogsĂĽ, at de danske virus ikke var tĂŚt beslĂŚgtet med H7N9 virus fra Kina. Endnu et nyt tiltag var etablering af et PCR assay, til screening af AI virus positive prøver specifikt for H9 subtypen. Der er en stigende bevĂĽgenhed overfor netop denne subtype af virus, da det har opnĂĽet enzootisk udbredelse i flere dele af verden, herunder Kina og Mellemøsten Der blev pĂĽvist H9N2 virus i 5 prøver, indsamlet pĂĽ samme lokalitet. Sekvens- og fylogenetisk analyse viste, at de danske H9N2 virus var beslĂŚgtet med virus fundet i vilde fugle i vores nabolande. Som supplement til overvĂĽgningen gennemførtes i 2014 en indsamling af tørsvabere parallelt med almindelige âvĂĽdeâ svabere udtaget i kloakmedie. De opnĂĽede resultater var meget lovende, og PCR resultaterne var enslydende uanset om analyserne blev kørt pĂĽ tørsvabere eller almindelige vĂĽde svabere. FormĂĽlet med den aktive overvĂĽgning var at foretage en screening for LPAI virus og at karakterisere de identificerede virus. Som de foregĂĽende ĂĽr, viste resultaterne fra overvĂĽgningen i 2014, at fuglearten er den mest betydende faktor for, at en given prøve er positiv. NĂŚsten alle positive prøver var fra grĂĽĂŚnder. OvervĂĽgningen var i forhold til tidligere udvidet i 2014 med en molekylĂŚr karakterisering af de virus, der blev pĂĽvist bĂĽde i vilde fugle og i fjerkrĂŚ, og dette bidrog til en dybere og mere prĂŚcis karakterisering af virus, sĂĽ vi ret prĂŚcist ved hvilke virus varianter, vi har pĂĽvist. Dermed er opnĂĽet en god indikation af hvilke AI virus, der cirkulerer i Danmark, og en viden om at disse virus pt. ikke udgør en øget trussel mod den humane sundhed. OvervĂĽgningen viser dog, at der til stadighed cirkulerer LPAI H5 og H7 virus i den vilde fauna, som potentielt kan true dyresundheden, sĂĽ der er behov for at overvĂĽge forekomsten af AI virus i fjerkrĂŚflokke. Karakterisering af virus fra gentagne indsendelser af opdrĂŚttet fjervildt understregede nødvendigheden af en løbende test af grĂĽandebesĂŚtninger, da virus kan persistere i lĂŚngere tid i besĂŚtningerne, hvilken er en velkendt risikofaktor for udvikling af HPAI fra LPAI med subtyperne H5 og H7
A new methodology to simulate subglacial deformation of water-saturated granular material
The dynamics of glaciers are to a large degree governed by processes
operating at the iceâbed interface, and one of the primary
mechanisms of glacier flow over soft unconsolidated sediments is
subglacial deformation. However, it has proven difficult to
constrain the mechanical response of subglacial sediment to the
shear stress of an overriding glacier. In this study, we present
a new methodology designed to simulate subglacial deformation using
a coupled numerical model for computational experiments on
grain-fluid mixtures. The granular phase is simulated on a per-grain
basis by the discrete element method. The pore water is modeled as
a compressible Newtonian fluid without inertia. The numerical
approach allows close monitoring of the internal behavior under
a range of conditions.
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Our computational experiments support the findings of previous studies
where the rheology of a slowly deforming water-saturated granular bed in the
steady state generally conforms to the rate-independent plastic rheology.
Before this so-called critical state, deformation is in many cases accompanied
by volumetric changes as grain rearrangement in active shear zones changes the
local porosity. For previously consolidated beds porosity
increases can cause local pore-pressure decline, dependent on till
permeability and shear rate. We observe that the pore-water pressure reduction
strengthens inter-granular contacts, which results in increased shear strength
of the granular material. In contrast, weakening takes place when shear
deformation causes consolidation of dilated sediments or during rapid fabric
development. Both processes of strengthening and weakening depend inversely on
the sediment permeability and are transient phenomena tied to the porosity
changes during the early stages of shear.
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We find that the transient strengthening and weakening in turn influences the
distribution of shear strain in the granular bed. Dilatant strengthening has
the ability to distribute strain during early deformation to large depths, if
sediment dilatancy causes the water pressure at the iceâbed interface to
decline. Oppositely, if the iceâbed interface is hydrologically stable the
strengthening process is minimal and instead causes shallow deformation. The
depth of deformation in subglacial beds thus seems to be governed by not only
local grain and pore-water feedbacks but also larger-scale hydrological
properties at the ice base
Dealing with a traumatic past: the victim hearings of the South African truth and reconciliation commission and their reconciliation discourse
In the final years of the twentieth and the beginning of the twenty-first century, there has been a worldwide tendency to approach conflict resolution from a restorative rather than from a retributive perspective. The South African Truth and Reconciliation Commission (TRC), with its principle of 'amnesty for truth' was a turning point. Based on my discursive research of the TRC victim hearings, I would argue that it was on a discursive level in particular that the Truth Commission has exerted/is still exerting a long-lasting impact on South African society. In this article, three of these features will be highlighted and illustrated: firstly, the TRC provided a discursive forum for thousands of ordinary citizens. Secondly, by means of testimonies from apartheid victims and perpetrators, the TRC composed an officially recognised archive of the apartheid past. Thirdly, the reconciliation discourse created at the TRC victim hearings formed a template for talking about a traumatic past, and it opened up the debate on reconciliation. By discussing these three features and their social impact, it will become clear that the way in which the apartheid past was remembered at the victim hearings seemed to have been determined, not so much by political concerns, but mainly by social needs
Water Solubilization Using Nonionic Surfactants from Renewable Sources in Microemulsion Systems
In this study the effect of temperature, NaCl and oils (hydrocarbons: C8âC16) on the formation and solubilization capacity of the systems of oil/monoacylglycerols (MAG):ethoxylated fatty alcohols (CEO20)/propylene glycol (PG)/water was investigated. The effects of the surfactant mixture on the phase behavior and the concentration of water or oil in the systems were studied at three temperatures (50, 55, 60 °C) and with varied NaCl solutions (0.5; 2; 11%). Electrical conductivity measurement, FTIR spectroscopy and the DSC method were applied to determine the structure and type of the microemulsions formed. The dimension of the microemulsion droplets was characterized by dynamic light scattering. It has been stated that the concentration of CEO20 has a strong influence on the shape and extent of the microemulsion areas. Addition of a nonionic surfactant to the mixture with MAG promotes an increase in the area of microemulsion formation in the phase diagrams, and these areas of isotropic region did not change considerably depending on the temperature, NaCl solution and oil type. It was found that, depending on the concentration of the surfactant mixture, it was possible to obtain U-type microemulsions with dispersed particles size distribution ranging from 25 to 50 nm and consisting of about 30â32% of the water phase in the systems. The conditions under which the microemulsion region was found (electrolyte and temperatureâinsensitive, comparatively low oil and surfactant concentration) could be highly useful in detergency
The quiet editor: Ivan VladislaviÄ and South African cultural production
This article examines the literary and sociological significance of Ivan VladislaviÄâs "double lifeâ (Lahire, 2010: n.p.) as both editor and writer. With reference to a number of his editorial roles as well as the joint projects he has worked on with writers and visual artists, the article considers how VladislaviÄâs work with others spreads symbolic value. Described by one of his clients as the âquiet editorâ, VladislaviÄ can be read as a new kind of author; what he terms âcreative editingâ (Steyn, 2012: n.p.) as a new kind of writing, through which more traditional models of authorship and literary production are thrown into question â less Bourdieuâs (1984) âfield of literary productionâ or Casanovaâs (2004: 82) âworld literary spaceâ, red in tooth and claw, amd more Howard Beckerâs âart worldâ: a convivial ânetwork of cooperating people, all of whose work is essential to the final outcomeâ (1982: 25)
The racist bodily imaginary: the image of the body-in-pieces in (post)apartheid culture
This paper outlines a reoccurring motif within the racist imaginary of (post)apartheid culture: the black body-in-pieces. This disturbing visual idiom is approached from three conceptual perspectives. By linking ideas prevalent in Frantz Fanonâs description of colonial racism with psychoanalytic concepts such as Lacanâs notion of the corps morcelĂŠ, the paper offers, firstly, an account of the black body-in-pieces as fantasmatic preoccupation of the (post)apartheid imaginary. The role of such images is approached, secondly, through the lens of affect theory which eschews a representational âreadingâ of such images in favour of attention to their asignifying intensities and the role they play in effectively constituting such bodies. Lastly, Judith Butlerâs discussion of war photography and the conditions of grievability introduces an ethical dimension to the discussion and helps draw attention to the unsavory relations of enjoyment occasioned by such images
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