5,721 research outputs found
An ecological approach to problems of Dark Energy, Dark Matter, MOND and Neutrinos
Modern astronomical data on galaxy and cosmological scales have revealed
powerfully the existence of certain dark sectors of fundamental physics, i.e.,
existence of particles and fields outside the standard models and inaccessible
by current experiments. Various approaches are taken to modify/extend the
standard models. Generic theories introduce multiple de-coupled fields A, B, C,
each responsible for the effects of DM (cold supersymmetric particles), DE
(Dark Energy) effect, and MG (Modified Gravity) effect respectively. Some
theories use adopt vanilla combinations like AB, BC, or CA, and assume A, B, C
belong to decoupled sectors of physics. MOND-like MG and Cold DM are often
taken as opposite frameworks, e.g. in the debate around the Bullet Cluster.
Here we argue that these ad hoc divisions of sectors miss important clues from
the data. The data actually suggest that the physics of all dark sectors is
likely linked together by a self-interacting oscillating field, which governs a
chameleon-like dark fluid, appearing as DM, DE and MG in different settings. It
is timely to consider an interdisciplinary approach across all semantic
boundaries of dark sectors, treating the dark stress as one identity, hence
accounts for several "coincidences" naturally.Comment: 12p, Proceedings to the 6-th Int. Conf. of Gravitation and Cosmology.
Neutrino section expande
Electrospun fixed dose combination fibers for the treatment of cardiovascular disease
Fixed dose combinations (FDCs) offer an accessible way to simplify complex therapeutic regimens by the simultaneous presentation of multiple drugs in a single entity to the patient. However, encapsulation of hydrophobic drugs into FDCs possess a number of technical challenges. Electrospun nanofibers offer a convenient way to incorporate multiple hydrophobic drugs into a single formulation in a single step, via the use of an appropriate organic solvent system during fabrication. In this study, we report a series of novel fiber formulations comprising ethyl cellulose loaded with two hydrophobic drugs, spironolactone and nifedipine, either individually or in combination. The drugs are found to be present in the fibers in the form of amorphous solid dispersions, and these are stable at room temperature for 4 months. The products showed extended release profiles over more than 30 h. This formulation strategy offers potential to manage chronic cardiovascular conditions and overcome patient related non-adherence by providing a simplified treatment model
Quantifying the Environmental Design Trades for a State-of-the-Art Turbofan Engine
Aircraft and engine technology have continuously evolved since their introduction and significant improvement has been made in fuel efficiency, emissions, and noise reduction. One of the major issues that the aviation industry is facing today is pollution around the airports, which has an effect both on human health and on the climate. Although noise emissions do not have a direct impact on climate, variations in departure and arrival procedures influence both CO2 and non-CO2 emissions. In addition, design choices made to curb noise might increase CO2 and vice versa. Thus, multidisciplinary modeling is required for the assessment of these interdependencies for new aircraft and flight procedures. A particular aspect that has received little attention is the quantification of the extent to which early design choices influence the trades of CO2, NOx, and noise. In this study, a single aisle thrust class turbofan engine is optimized for minimum installed SFC (Specific Fuel Consumption). The installed SFC metric includes the effect of engine nacelle drag and engine weight. Close to optimal cycles are then studied to establish how variation in engine cycle parameters trade with noise certification and LTO (Landing and Take-Off) emissions. It is demonstrated that around the optimum a relatively large variation in cycle parameters is allowed with only a modest effect on the installed SFC metric. This freedom in choosing cycle parameters allows the designer to trade noise and emissions. Around the optimal point of a state-of-the-art single aisle thrust class propulsion system, a 1.7 dB reduction in cumulative noise and a 12% reduction in EINOx could be accomplished with a 0.5% penalty in installed SFC
Environmental Assessment of Noise Abatement Approach Trajectories
Noise abatement procedures are one of the main actions implemented to reduce noise pollution around airports. In this study, the focus is turned on approach operations and their environmental impact. The assessment starts from standard optimized procedures, namely the Continuous Descent Approach (CDA) and the Low Drag Low Power (LDLP) and the aim is to look into more advanced procedures, such as a Steep and a Segmented CDA, an Advanced LDLP and an optimized trajectory for the specific flight conditions. The procedures are designed for an A321neo and compared and evaluated for noise and emissions. It is demonstrated that multidisciplinary design and adaptation to specific conditions are required for the assessment of these interdependencies for flight procedures
An Edgeworth expansion for finite population L-statistics
In this paper, we consider the one-term Edgeworth expansion for finite
population L-statistics. We provide an explicit formula for the Edgeworth
correction term and give sufficient conditions for the validity of the
expansion which are expressed in terms of the weight function that defines the
statistics and moment conditions.Comment: 14 pages. Minor revisions. Some explanatory comments and a numerical
example were added. Lith. Math. J. (to appear
SUSTAINABLE AVIATION FOR SWEDEN - TECHNOLOGY & CAPABILITY ASSESSMENT TARGETING 2045
The goal of this project is to analyse the possibilities offered by different technological solutions to achieve zero emission aviation, firstly in the Swedish/Nordic network context and secondly extend this to the European context. This project will investigate the potential and feasibility of new or upgraded aircraft types based on the different technologies mapped from both, various published roadmaps and national expertise from Swedish aerospace universities and companies. This involves developing aircraft conceptual designs studies and trade analysis with regards to different fuel types, propulsion technologies, structure, operations, network and fleet management, and all relevant technologies. The project will, on a common technology basis, analyse a range of zero carbon fuels and associated technologies through operational studies and optimization to accelerate the introduction of fossil free aircraft technology and choosing optimal paths for making aviation sustainable
Ultrathin chalcogenide nanosheets for photoacoustic imaging-guided synergistic photothermal/gas therapy.
Previous preclinical and clinical studies have shown that using only a single therapy makes it difficult to completely eradicate tumors and restrain cancer metastasis. To overcome this challenge, multi-modal synergistic treatments have attracted considerable attention. Herein, an ultrathin Cu-loaded CoCuFe-selenide (CCFS) was prepared by a facile topotactic transformation from CoCuFe layered double hydroxide (LDH) nanosheets (NSs), followed by surface modification with polyvinyl pyrrolidone (PVP) and l-arginine (L-Arg). The resultant CCFS-PVP-L-Arg (CPA) system shows excellent synergetic photothermal and gas therapy (PTT/GT). The CCFS NSs have strong LSPR absorbance characteristic, with enhanced light absorption in the near-infrared (NIR) region. This endows the CPA nanocomposite with an outstanding photothermal conversion efficiency of 72.0% (pH 7.4) and 81.0% (pH 5.4), among the highest reported for 2D chalcogenide nanomaterials. In addition, NO release from CPA is triggered by decomposition of L-Arg in the H2O2-rich and acidic tumor microenvironment, permitting localized NO gas therapy in the tumor site. In vitro experiments revealed 91.8% apoptosis of HepG2 cells, and in vivo studies showed complete tumor elimination upon treatment with the CPA nanocomposite under NIR irradiation. To the best of our knowledge, this is the first report of combined defect-induced high-efficiency PTT with H2O2 and pH targeted GT
The solid modeling of the fillet on the intersection line of two cylinders
2005-2006 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
The forming theory and nc machining of the rotary burs with special cutting edges
2005-2006 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
Calibration of Traffic Simulation Models using SPSA
Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) “Γεωπληροφορική
- …