5,800 research outputs found
Energy autonomy in residential buildings: a techno-economic modelbased analysis of the scale effects
An increasingly decentralized energy supply structure alongside economic incentives for increasing the level of self-generation and –consumption are encouraging (higher levels of) energy autonomy. Previous work in this area has focused on the technical and economic aspects of energy autonomy at distinct scales, from individual buildings, through neighbourhoods to districts. This paper employs a mixed integer linear program (MILP) to assess the effects of aggregation across these scales on the economics of energy autonomy in residential buildings. The model minimizes total energy system costs over the lifetime of the energy system, including micro-CHP, PV, thermal and electrical storage, and boilers, at five distinct scales and for nine demand cases. It is subject to several constraints, amongst other things the degree of electrical self-sufficiency. The results indicate a shift in the economically optimal level of electrical self-sufficiency with scale, which in Single Family Households (SFHs) means from around 30% at the individual building level to almost 100% in districts of 1000 SFH households. Above around 560 households it could be economically advantageous to make a district of residential buildings electrically self-sufficient. In addition, a marginal increase in electrical selfsufficiency is significantly more expensive at lower aggregation scales (i.e. single buildings) compared to the scale of neighbourhoods and districts. The level of interaction with the electrical distribution network increases with increasing electrical self-sufficiency before then decreasing at very high (above 70%) levels. Future work should focus on a richer socioeconomic differentiation, considering other sectors and technologies, incorporating demand side options and analysing the effects on the overarching energy system
Polycation-siRNA nanoparticles can disassemble at the kidney glomerular basement membrane
Despite being engineered to avoid renal clearance, many cationic polymer (polycation)-based siRNA nanoparticles that are used for systemic delivery are rapidly eliminated from the circulation. Here, we show that a component of the renal filtration barrier—the glomerular basement membrane (GBM)—can disassemble cationic cyclodextrin-containing polymer (CDP)-based siRNA nanoparticles and, thereby, facilitate their rapid elimination from circulation. Using confocal and electron microscopies, positron emission tomography, and compartment modeling, we demonstrate that siRNA nanoparticles, but not free siRNA, accumulate and disassemble in the GBM. We also confirm that the siRNA nanoparticles do not disassemble in blood plasma in vitro and in vivo. This clearance mechanism may affect any nanoparticles that assemble primarily by electrostatic interactions between cationic delivery components and anionic nucleic acids (or other therapeutic entities)
Modellgestützte Bewertung des Kraft-Wärme-Kopplungsgesetzes 2016 anhand ausgewählter Anwendungsfälle in Wohngebäuden
Der Kraft-Wärme-Kopplung wird auf Grund ihrer Energieeffizienz, breiten Anwendungsmöglichkeit in den Nachfragesektoren sowie Erzeugungsflexibilität eine Schlüsselrolle in der Umsetzung der Energiewende zugeschrieben. Die Energiepolitik der Bundesregierung in Deutschland sieht daher eine bedeutende Steigerung des Anteils dieser Technologie an der Elektrizitätserzeugung in zukünftigen Jahren vor. Als Instrument zur staatlichen Förderung des Ausbaus existiert zur Zielerreichung unter anderem das Kraft-Wärme-Kopplungsgesetz (KWKG) seit 2002. Zuletzt wurde dieses 2016 umfassend überarbeitet und enthält gewichtige Änderungen zur Vorgängerfassung, unter anderem zur Höhe und Dauer der Zuschlagzahlungen. Ziel dieses Beitrages ist die Bewertung dieser Veränderungen hinsichtlich technischer, wirtschaftlicher und ökologischer Aspekte mithilfe eines modellgestützten Ansatzes für ausgewählte Fallbeispiele zur Elektrizitäts- und Wärmeversorgung von Wohngebäuden für unterschiedliche räumliche Aggregationsebenen vom Einzelgebäude bis hin zum Quartier. Im Ergebnis zeigt sich für das Bezugsjahr 2016 die ökonomische Vorteilhaftigkeit des KWK-Einsatzes unter den Förderbedingungen des KWKG 2016 gegenüber des KWKG 2002 (zuletzt 2012 novelliert) für die Anwendungsfälle der mittleren betrachteten Aggregationsebenen (Straßenzüge und Häuserblöcke). Dagegen ist eine Umkehr der Wirtschaftlichkeit im Vergleich zu den Rahmenbedingungen der Vorgängerfassung für höhere Aggregationsebenen (Siedlung, Quartier) festzustellen. Bei letzteren kommt es insbesondere zu einer vergleichsweise kleineren Auslegung der Anlagen bei gleichzeitig höherer Vollbenutzungsstundenanzahl. Des Weiteren werden in diesem Beitrag Implikationen der KWKG-Neufassung von 2016 hinsichtlich technischer und ökologischer Aspekte aufgezeigt
Integrated planning guidance material for example UWCS development
Where to be in 2050? How to facilitate change towards sustainable urban water service? Policy makers are challenged with rising and emerging change pressures on traditional urban water management practices and infrastructures. Changing social, economic and environmental patterns will affect the urban water services of tomorrow - the backbone of our society. This guide centres the urban water management transitions framework by Brown et al. 2009 characterising the evolution and the example future UWCS development. Furthermore, this guide provides information and assistance for shaping the transition towards the described, desirable urban water futures by addressing visioning, lock-in effects, tools to measure the current state of sustainability, principles of resilience, flexibility and adaptivity in terms of urban water systems and the five dimensions of UWCS sustainability regarding future pressures and trends about, among others, climate change, population growth and changing water demand.Nottarp-Heim, D.; Merkel, W.; Alegre, H.; Gormley, A.; Hein, A.; Alegre (2015). Integrated planning guidance material for example UWCS development. http://hdl.handle.net/10251/4745
Discovery of extremely halophilic, methyl-reducing euryarchaea provides insights into the evolutionary origin of methanogenesis
Methanogenic archaea are major players in the global carbon cycle and in the biotechnology of anaerobic digestion. The phylum Euryarchaeota includes diverse groups of methanogens that are interspersed with non-methanogenic lineages. So far, methanogens inhabiting hypersaline environments have been identified only within the order Methanosarcinales. We report the discovery of a deep phylogenetic lineage of extremophilic methanogens in hypersaline lakes and present analysis of two nearly complete genomes from this group. Within the phylum Euryarchaeota, these isolates form a separate, class-level lineage 'Methanonatronarchaeia' that is most closely related to the class Halobacteria. Similar to the Halobacteria, 'Methanonatronarchaeia' are extremely halophilic and do not accumulate organic osmoprotectants. The high intracellular concentration of potassium implies that 'Methanonatronarchaeia' employ the 'salt-in' osmoprotection strategy. These methanogens are heterotrophic methyl-reducers that use C 1 -methylated compounds as electron acceptors and formate or hydrogen as electron donors. The genomes contain an incomplete and apparently inactivated set of genes encoding the upper branch of methyl group oxidation to CO2 as well as membrane-bound heterodisulfide reductase and cytochromes. These features differentiate 'Methanonatronarchaeia' from all known methyl-reducing methanogens. The discovery of extremely halophilic, methyl-reducing methanogens related to haloarchaea provides insights into the origin of methanogenesis and shows that the strategies employed by methanogens to thrive in salt-saturating conditions are not limited to the classical methylotrophic pathway.Accepted Author ManuscriptBT/Environmental Biotechnolog
A measurement of the axial form factor of the nucleon by the p(e,e'pi+)n reaction at W=1125 MeV
The reaction p(e,e'pi+)n was measured at the Mainz Microtron MAMI at an
invariant mass of W=1125 MeV and four-momentum transfers of Q^2=0.117, 0.195
and 0.273 (GeV/c)^2. For each value of Q^2, a Rosenbluth separation of the
transverse and longitudinal cross sections was performed. An effective
Lagrangian model was used to extract the `axial mass' from experimental data.
We find a value of M_A=(1.077+-0.039) GeV which is (0.051+-0.044) GeV larger
than the axial mass known from neutrino scattering experiments. This is
consistent with recent calculations in chiral perturbation theory.Comment: 14 pages, 5 figures, uses elsart.cl
Deep-Inelastic Inclusive ep Scattering at Low x and a Determination of alpha_s
A precise measurement of the inclusive deep-inelastic e^+p scattering cross
section is reported in the kinematic range 1.5<= Q^2 <=150 GeV^2 and
3*10^(-5)<= x <=0.2. The data were recorded with the H1 detector at HERA in
1996 and 1997, and correspond to an integrated luminosity of 20 pb^(-1). The
double differential cross section, from which the proton structure function
F_2(x,Q^2) and the longitudinal structure function F_L(x,Q^2) are extracted, is
measured with typically 1% statistical and 3% systematic uncertainties. The
measured partial derivative (dF_2(x,Q^2)/dln Q^2)_x is observed to rise
continuously towards small x for fixed Q^2. The cross section data are combined
with published H1 measurements at high Q^2 for a next-to-leading order DGLAP
QCD analysis.The H1 data determine the gluon momentum distribution in the range
3*10^(-4)<= x <=0.1 to within an experimental accuracy of about 3% for Q^2 =20
GeV^2. A fit of the H1 measurements and the mu p data of the BCDMS
collaboration allows the strong coupling constant alpha_s and the gluon
distribution to be simultaneously determined. A value of alpha
_s(M_Z^2)=0.1150+-0.0017 (exp) +0.0009-0.0005 (model) is obtained in NLO, with
an additional theoretical uncertainty of about +-0.005, mainly due to the
uncertainty of the renormalisation scale.Comment: 68 pages, 24 figures and 18 table
Searches at HERA for Squarks in R-Parity Violating Supersymmetry
A search for squarks in R-parity violating supersymmetry is performed in e^+p
collisions at HERA at a centre of mass energy of 300 GeV, using H1 data
corresponding to an integrated luminosity of 37 pb^(-1). The direct production
of single squarks of any generation in positron-quark fusion via a Yukawa
coupling lambda' is considered, taking into account R-parity violating and
conserving decays of the squarks. No significant deviation from the Standard
Model expectation is found. The results are interpreted in terms of constraints
within the Minimal Supersymmetric Standard Model (MSSM), the constrained MSSM
and the minimal Supergravity model, and their sensitivity to the model
parameters is studied in detail. For a Yukawa coupling of electromagnetic
strength, squark masses below 260 GeV are excluded at 95% confidence level in a
large part of the parameter space. For a 100 times smaller coupling strength
masses up to 182 GeV are excluded.Comment: 32 pages, 14 figures, 3 table
Multi-Jet Event Rates in Deep Inelastic Scattering and Determination of the Strong Coupling Constant
Jet event rates in deep inelastic ep scattering at HERA are investigated
applying the modified JADE jet algorithm. The analysis uses data taken with the
H1 detector in 1994 and 1995. The data are corrected for detector and
hadronization effects and then compared with perturbative QCD predictions using
next-to-leading order calculations. The strong coupling constant alpha_S(M_Z^2)
is determined evaluating the jet event rates. Values of alpha_S(Q^2) are
extracted in four different bins of the negative squared momentum
transfer~\qq in the range from 40 GeV2 to 4000 GeV2. A combined fit of the
renormalization group equation to these several alpha_S(Q^2) values results in
alpha_S(M_Z^2) = 0.117+-0.003(stat)+0.009-0.013(syst)+0.006(jet algorithm).Comment: 17 pages, 4 figures, 3 tables, this version to appear in Eur. Phys.
J.; it replaces first posted hep-ex/9807019 which had incorrect figure 4
Multiplicity Structure of the Hadronic Final State in Diffractive Deep-Inelastic Scattering at HERA
The multiplicity structure of the hadronic system X produced in
deep-inelastic processes at HERA of the type ep -> eXY, where Y is a hadronic
system with mass M_Y< 1.6 GeV and where the squared momentum transfer at the pY
vertex, t, is limited to |t|<1 GeV^2, is studied as a function of the invariant
mass M_X of the system X. Results are presented on multiplicity distributions
and multiplicity moments, rapidity spectra and forward-backward correlations in
the centre-of-mass system of X. The data are compared to results in e+e-
annihilation, fixed-target lepton-nucleon collisions, hadro-produced
diffractive final states and to non-diffractive hadron-hadron collisions. The
comparison suggests a production mechanism of virtual photon dissociation which
involves a mixture of partonic states and a significant gluon content. The data
are well described by a model, based on a QCD-Regge analysis of the diffractive
structure function, which assumes a large hard gluonic component of the
colourless exchange at low Q^2. A model with soft colour interactions is also
successful.Comment: 22 pages, 4 figures, submitted to Eur. Phys. J., error in first
submission - omitted bibliograph
- …