263 research outputs found
Ab initio prediction of magnetically dead layers in freestanding -Ce(111)
It is well known that the surface of nonmagnetic -Ce is magnetically
ordered, i.e., -like. One then might conjecture, in agreement with
previous theoretical predictions, that the -Ce may also exhibit at its
surfaces even more strongly enhanced -like magnetic ordering.
Nonetheless, our result shows that the (111)-surfaces of magnetic -Ce
are neither spin nor orbitally polarized, i.e., -like. Therefore, we
predict, in contrast to the nonmagnetic -phase which tends to produce
magnetically ordered -like thin layers at its free surfaces, the
magnetic -phase has a tendency to form -like dead layers. This
study, which explains the suppressed (promoted) surface magnetic moments of
-Ce (-Ce), shows that how nanoscale can reverse physical
properties by going from bulk to the surface in isostructural - and
-phases of cerium. We predict using our freestanding surface results
that a typical unreactive and non-diffusive substrate can dramatically
influence the magnetic surface of cerium thin films in contrast to most of the
uncorrelated thin films and strongly correlated transition metals. Our result
implies that magnetic surface moments of -Ce(111) can be suddenly
disappeared by increasing lattice mismatch at the interface of a typical
unreactive and non-diffusive substrate with cerium overlayers.Comment: 6 pages, 3 figures, 1 tabl
Experimental and numerical studies of hybrid PCM embedded in plastering mortar for enhanced thermal behaviour of buildings
This paper proposes a methodology for improvement of energy efficiency in buildings through the innovative simultaneous incorporation of three distinct phase change materials (here termed as hybrid PCM) in plastering mortars for façade walls. The thermal performance of a hybrid PCM mortar was experimentally evaluated by comparing the behaviour of a prototype test cell (including hybrid PCM plastering mortar) subjected to realistic daily temperature profiles, with the behaviour of a similar prototype test cell, in which no PCM was added. A numerical simulation model was employed (using ANSYS-FLUENT) to validate the capacity of simulating temperature evolution within the prototype containing hybrid PCM, as well as to understand the contribution of hybrid PCM to energy efficiency. Incorporation of hybrid PCM into plastering mortars was found to have the potential to significantly reduce heating/cooling temperature demands for maintaining the interior temperature within comfort levels when compared to normal mortars (without PCM), or even mortars comprising a single type of PCM.The authors would like to acknowledge the financial support of
the Foundation for Science and Technology (FCT) in the frame of: (i)
project CENTRO-07-ST24_FEDER-002020; (ii) project PTDC/ECM/
102154/2008; (iii) C-TAC, ISISE and CeMADE research units
Avaliação experimental de compósitos de agregados leves impregnados com PCM, para aplicação em pavimentos rodoviários
Este trabalho visa, em primeiro lugar, a caracterização experimental do comportam
ento de argamassas com materiais de
mudança de fase (PCM) incorporados através de agregados leves, comparativamente com argamassas de referência sem incorporação de PCM. Verifica-se que a aplicação de argamassas com PCM em camadas de desgaste de pavimentos
contribui para a minimização dos potenciais efeitos negativos de gelo e degelo. Os estudos experimentais permitem concluir que o método utilizado de impregnação de PCM em materiais porosos, para posterior incorporação em
argamassa ou betão, é um método simples, mas muito eficaz. Os resultados indicam ainda que os materiais compósitos com PCM incorporado, podem melhorar a inércia térmica, bem como, atrasar o tempo de eventual ocorrência de congelamento sob a camada de desgaste de um pavimentoComissão de Coordenação e Desenvolvimento Regional
da Região Centro (CCDR-C), através do projeto de
investigação CENTRO-07-ST24_FEDER-002020 “Environmentally-Friendly Aeronautical Transport Systems Integrated Program (EFATRAS)”,
http://efatrasubi.wordpress.co
Assessing the feasibility of impregnating phase change materials in lightweight aggregate for development of thermal energy storage systems
This paper assesses the feasibility of impregnation/encasement of phase change materials (PCMs) in
lightweight aggregates (LWAs). An impregnation process was adopted to carry out the encasement study
of two different PCMs in four different LWAs. The leakage of the impregnated/encased PCMs was studied
when they were submitted to freeze/thawing and oven drying tests, separately. The results confirmed
that, the impregnation/encasement method is effective with respect to the large thermal energy storage
density, and can be suitable for applications were PCMs cannot be incorporated directly such as asphalt
road pavements.The authors acknowledge the funding given by Centre for Coordination and Regional Development Committee (CCDR-C) through the research project CENTRO-07-ST24_FEDER-002020 "Environmentally-Friendly Aeronautical Transport Systems Integrated Program (EFATRAS)", http://efatrasubi.wordpress.com. Supply of Expanded Clay materials by ARGEX - Argila Expandida, S.A and Cork materials by Sofalca - Sociedade Central de Productos de Cortica, Lda are also acknowledged
Preliminary Evidence of Acceptance and Commitment Therapy for Death Anxiety in Iranian Clients Diagnosed with OCD
This study investigated the effectiveness of Acceptance and Commitment Therapy (ACT) on death anxiety and obsessive-compulsive disorder (OCD) with eight adult females in Iran. The ACT protocol was conducted in 8 weekly solo sessions (45 minutes each). The results were analyzed by visual analysis method and improvement percentage. ACT resulted in decreases in death anxiety (60-80%) and obsessive-compulsive symptoms (51-60%), thereby indicating promise for ACT as a treatment for OCD and death anxiety
Antioxidant enzyme activity and MDA level in the rat testis following chronic administration of ghrelin
Erratum: Neurogenesis and increase in differentiated neural cell survival via phosphorylation of akt1 after fluoxetine treatment of stem cells(BioMed Research International)
Dehydroepiandrosterone stimulates nerve growth factor and brain derived neurotrophic factor in cortical neurons
Due to the increasing cases of neurodegenerative diseases in recent years, the eventual goal of nerve repair is very important. One approach for achieving a neuronal cell induction is by regenerative pharmacology. Nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) are neurotrophins that play roles in neuronal development, differentiation, and protection. On the other hand, dehydroepiandrosterone (DHEA) is a neurosteroid which has multiple actions in the nervous system. DHEA could be an important agent in regenerative pharmacology for neuronal differentiation during tissue regeneration. In this study, we investigated the possible role of DHEA to modulate NGF and BDNF production. The in vivo level of neurotrophins expression was demonstrated by ELISA in rat harvested brain cortex. Also neurotrophins expression after DHEA treatment was revealed by the increased neurite extension, immunostaining, and BrdU labeling in rats. Anti-NGF and anti-BDNF antibodies were used as suppressive agents on neurogenesis. The results showed that NGF and BDNF are overproduced after DHEA treatment but there is not any overexpression for NT-3 and NT-4. Also DHEA increased neurite extension and neural cell proliferation significantly. Overall, DHEA might induce NGF and BDNF neurotrophins overproduction in cortical neurons which promotes neural cell protection, survival, and proliferation. © 2013 Anahita Rahmani et al
Erratum: Neurogenesis and increase in differentiated neural cell survival via phosphorylation of akt1 after fluoxetine treatment of stem cells(BioMed Research International)
- …