The Coincidence Problem in Holographic f(R) Gravity

It is well-known that $f(R)$ gravity models formulated in Einstein conformal frame are equivalent to Einstein gravity together with a minimally coupled scalar field. In this case, the scalar field couples with the matter sector and the coupling term is given by the conformal factor. We apply the holographic principle to such interacting models. In a spatially flat universe, we show that the Einstein frame representation of $f(R)$ models leads to a constant ratio of energy densities of dark matter to dark energy.Comment: 10 pages, no figure

Mach's Principle and Model for a Broken Symmetric Theory of Gravity

We investigate spontaneous symmetry breaking in a conformally invariant gravitational model. In particular, we use a conformally invariant scalar tensor theory as the vacuum sector of a gravitational model to examine the idea that gravitational coupling may be the result of a spontaneous symmetry breaking. In this model matter is taken to be coupled with a metric which is different but conformally related to the metric appearing explicitly in the vacuum sector. We show that after the spontaneous symmetry breaking the resulting theory is consistent with Mach's principle in the sense that inertial masses of particles have variable configurations in a cosmological context. Moreover, our analysis allows to construct a mechanism in which the resulting large vacuum energy density relaxes during evolution of the universe.Comment: 9 pages, no figure

Transport Properties in Ferromagnetic Josephson Junction between Triplet Superconductors

Charge and spin Josephson currents in a ballistic superconductor-ferromagnet-superconductor junction with spin-triplet pairing symmetry are studied using the quasiclassical Eilenberger equation. The gap vector of superconductors has an arbitrary relative angle with respect to magnetization of the ferromagnetic layer. We clarify the effects of the thickness of ferromagnetic layer and magnitude of the magnetization on the Josephson charge and spin currents. We find that 0-\pi transition can occur except for the case that the exchange field and d-vector are in nearly perpendicular configuration. We also show how spin current flows due to misorientation between the exchange field and d-vector.Comment: 6 pages, 8 figure

Retrospective Investigation of Enteric Illnesses in Pet Animals

Recording and analysis of data are key elements to understand the epidemiology of various infectious and zoonotic diseases such as enteric pathogens and conditions. In this study, the clinical records of Alhelal Alazraq veterinary clinic in Tripoli were investigated for enteric diseases and illnesses in cats and dogs during the period of 2010–2015. The diagnostic and therapeutic guidelines within the Libyan veterinary system were also assessed and discussed based on the retrieved information and records. A total of 859 cases representing 528 (61%) from cats and 331 (39%) from dogs were retrieved and analysed using descriptive analysis. The cases were originated from five major areas from the center of Tripoli and the surrounding areas. Of these, 835/859 (97%) cases adopted antimicrobial based therapies and administered various antibiotic classes mainly and respectively using penicillin (652; 78%) and trimethoprim-sulfamethoxazole (229; 27%). The current study is the first retrospective investigation that analysed clinical and medical information from a major veterinary clinic in Libya. Diagnostic and therapeutic guidelines in the veterinary settings in Libya should be carefully reviewed and addressed. Retrospective studies and research programmes that monitor and investigate the occurrences of zoonotic and emerging pathogens particularly in relation to antimicrobial resistance are warranted in the Libyan health and medical system

Cosmic Acceleration in Brans-Dicke Cosmology

We consider Brans-Dicke theory with a self-interacting potential in Einstein conformal frame. We show that an accelerating expansion is possible in a spatially flat universe for large values of the Brans-Dicke parameter consistent with local gravity experiments.Comment: 10 Pages, 3 figures, To appear in General Relativity and Gravitatio

I feel that I am an Afghan who have Norwegian residency : experiencing social integration and identity development among unaccompanied minor refugees in Norway

Masteroppgave i sosialt arbeid - Universitetet i Nordland, Bodø 201

Impact of sulphur contamination on the performance of mixed ionic-electronic conducting membranes for oxygen separation and hydrogen production

PhD ThesisMixed ionic-electronic conducting (MIEC) membranes are a promising technology for oxygen separation but they are not commercialised yet due to sealing issue and sensitivity to impurities in feedstock. In this study, La0.6Sr0.4Co0.2Fe0.8O3- (LSCF6428) was successfully sealed for long-term operation of 963 h using a gold-glass-ceramic sealant. The membrane was then tested for air separation in presence of hydrogen sulphide for 100 h and results showed that the impurity caused a drop in oxygen flux to zero within few hours. The flux could not be fully restored after hydrogen sulphide removal and only 6 to 35% was recovered. It was proposed that hydrogen sulphide was adsorbed on the membrane in the form of sulphur and it occupied oxygen vacancies. With time, strontium segregates toward sulphur to form irreversible layer of strontium sulphate. To restore the damaged surface, the membrane was treated by 1% (mol) of hydrogen for 20 h and the recovery improved from 6 to 12%. It was discovered that the poisoning mechanism is a function of oxygen partial pressure and change of partial pressure from 0.21 to 0.01 bar resulted in 90% recovery and this can be used as a strategy to reduce the damage. The next step was to test the membrane for hydrogen production using 1% (mol) of methane and results showed that methane conversion was steady at 33% for 350 h. Methane oxidation was also carried in presence of hydrogen sulphide but it resulted in drop of conversion to 8%. However, the conversion was slowly regenerating with time and it reached a constant value of 15%. This recovery was interpreted by the reaction of methane with hydrogen sulphide or methane decomposition and the membrane acted as a catalyst for these reactions. After hydrogen sulphide removal from the feed, the conversion kept on decreasing and this was linked to the change of membrane properties and therefore the membrane could not provide the sites for methane-oxygen reaction. For better stability under hydrogen sulphide, the membrane was modified by adding a powder of LSCF6428 material over the dense membrane. This dual layer membrane was stable for air separation under hydrogen for 33 h and the flux was only reduced by 5%

Dynamics & Predictions in the Co-Event Interpretation

Sorkin has introduced a new, observer independent, interpretation of quantum mechanics that can give a successful realist account of the 'quantum microworld' as well as explaining how classicality emerges at the level of observable events for a range of systems including single time 'Copenhagen measurements'. This 'co-event interpretation' presents us with a new ontology, in which a single 'co-event' is real. A new ontology necessitates a review of the dynamical & predictive mechanism of a theory, and in this paper we begin the process by exploring means of expressing the dynamical and predictive content of histories theories in terms of co-events.Comment: 35 pages. Revised after refereein