24,065 research outputs found
Working memory learning method and astrocytes number in different subfields of rat's Hippocampus
The aim of this study was evaluation of the astrocytes number in different subfields of rat's Hippocampus after spatial learning with usage of Morris Water Maze technique and working memory method. In this study, between 2005-2006 years in Pasteur institute of Iran-Tehran and histological department of Gorgan University with usage of Morris Water Maze and working memory technique, we used 14 male albino wistar rats. Seventh rats were in control group and 7 rats in working memory group. After histological preparation, the slides were stained with PTAH staining for showing the Astrocytes. Present results showed significant difference in astrocytes number in CA1, CA2 and CA3 areas of hippocampus between control and reference memory group. The number of astrocytes is increased in working memory group. Then we divided the hippocampus to three parts: Anterior, middle and posterior and with compare of different area (CA1, CA2 and CA3) of hippocampus, we found that the differences between Anterior-middle and Middle-Posterior of CA1 and CA2 area of hippocampus were significant, whereas the difference between Anterior-Posterior parts was not significant in CA1 and CA2 areas. In CA3 area, the difference between Anterior-Middle and Anterior-Posterior parts was significant, whereas the difference between middle and posterior parts was not significant. We concluded that the number of astrocytes increased due to spatial learning and working memory technique. © 2008 Science Publications
The exp-log normal form of types
Lambda calculi with algebraic data types lie at the core of functional
programming languages and proof assistants, but conceal at least two
fundamental theoretical problems already in the presence of the simplest
non-trivial data type, the sum type. First, we do not know of an explicit and
implemented algorithm for deciding the beta-eta-equality of terms---and this in
spite of the first decidability results proven two decades ago. Second, it is
not clear how to decide when two types are essentially the same, i.e.
isomorphic, in spite of the meta-theoretic results on decidability of the
isomorphism.
In this paper, we present the exp-log normal form of types---derived from the
representation of exponential polynomials via the unary exponential and
logarithmic functions---that any type built from arrows, products, and sums,
can be isomorphically mapped to. The type normal form can be used as a simple
heuristic for deciding type isomorphism, thanks to the fact that it is a
systematic application of the high-school identities.
We then show that the type normal form allows to reduce the standard beta-eta
equational theory of the lambda calculus to a specialized version of itself,
while preserving the completeness of equality on terms. We end by describing an
alternative representation of normal terms of the lambda calculus with sums,
together with a Coq-implemented converter into/from our new term calculus. The
difference with the only other previously implemented heuristic for deciding
interesting instances of eta-equality by Balat, Di Cosmo, and Fiore, is that we
exploit the type information of terms substantially and this often allows us to
obtain a canonical representation of terms without performing sophisticated
term analyses
Empowering Distributed Solar PV Energy for Malaysian Rural Housing: Towards Energy Security and Equitability of Rural Communities
This paper illustrates on how Malaysia's development landscapes has been poweredby cheap oil and gas making it dependent and addicted on using large amounts of fossil fuels. As acountry that is primarily depended on fossil fuels for generating power supply, Malaysia needs tocogitate of long-term energy security due to fossil fuel depletion and peak oil issues. Loss of theseresources could leadto thereduction of power generation capacitywhich will threaten the stabilityof the electricity supply in Malaysia. This could potentially influence in an increase in electricitycosts which lead to a phase of power scarcity and load shedding for the country. With the risk ofinterrupted power supplies, rural households, especially those of low-income groups areparticularly vulnerable to the post-effects of a power outage and an inequitable distribution to thepeople. Distributed generation of electricity by solar PVs diminishes the vulnerability of thesehouseholds and can also offer an income to them by feeding the power supply to the national gridthrough Feed-in Tariff scheme. At the moment, the deployment of solar PV installations is still inthe introductory stage in Malaysia, where roof-mounted PV panels are only available to commercialand urban residential buildings. This is due to the lack of a suitable renewable energy policy forrural households and the high cost of the solar PV technology. This paper will put forward ananalysis for incorporating solar photovoltaic on roofs of rural houses by identifying the energyconsumption of these households and the extent to which PVs can alleviate electricity insecurity.The results present significant potential for distributed PV power generation in rural areas inMalaysia which shown a considerable amount of electricity needed to be harvested from roofmountedsolar PV for rural people in Malaysia
Integrating vocational training in culinary arts and Islamic studies at juvenile rehabilitation centres: Malaysian experience
The Juvenile Rehabilitation Centres (JRC) in Malaysia aims to provide shelter, counselling and skills training to juveniles specifically for those who wish to transform themselves from the regrettable misdeeds they have committed. At JRCs, an integrated Culinary Vocational Training and Islamic education forms part of their training curriculum. The skills acquired should enable trainees to secure jobs upon completion of training. However, there are some training institutions that lack systematic training structures resulting in trainees becoming less skilful in both vocational and Islamic education. The objective of this research is to identify the effectiveness of an integrated Culinary and Islamic Education curriculum implemented at JRCs in Malaysia. This is a descriptive survey and data was obtained using questionnaire and interview. Respondents comprised 92 trainees, four managers, four culinary trainers and four Islamic education teachers, all from four different JRCs. The findings show that the trainees are happy with their trainings that brought about positive effects for them. Some suggestions have been made to provide improvements in the implementation of the course among them the inclusion of prayers in the Islamic education syllabus
The performance of modified jatropha-based nanofluid during turning process
The industry's extensive use of petroleum-based metalworking fluid (MWF) harms the environment
and humans. The production of bio-based MWF, especially from crude jatropha oil (CJO), has therefore taken
numerous initiatives. This aimed to formulate newly modified jatropha oil (MJO) with the addition of 0.05wt.%
hBN and 0.05wt.% MoS2 as the nanofluid for MWF. The performance of the nanofluids was determined
through the turning process in terms of cutting temperature, workpiece surface roughness, tool life and tool
wear of the tool lubricated by the nanofluids. The performance of the nanofluid samples was compared with
the synthetic ester (SE). From the results, after conducted 100mm axial cutting length MJO+hBN+MoS2
recorded the lowest in cutting temperature and surface roughness compared to all samples. The result shows
that MJO+hBN+MoS2 has longer tool life (6500mm) compared to SE (6000mm). Abrasion and adhesion were
observed as the dominant tool wear mechanism. In conclusion, MJO+hBN+MoS2 shows better machining
performance and has the potential to be an environmentally friendly metalworking fluid
Microstructure development, mechanical and tribological properties of a semisolid A356/xSiCp composite
This paper presents the results of experimental investigation on microstructure (size and morphology of eutectic Si), impact toughness and sliding wear properties of A356 Al-Si alloy and composites containing 10, 20 and 25 wt% of SiCp reinforcement produced by semisolid stirring technique. The results revealed that an increase in SiCp content leads to a reduction in the size of eutectic Si and also changes its morphology from plate-like to equiaxed. Furthermore, addition of 10 and 20 wt% silicon carbide reinforcement decreased the impact toughness by 6 and 18%, respectively. A356/25wt%SiCp composite registered the lowest impact toughness with reduction of 33% due to debonding and agglomeration of SiCp in the matrix. The sliding wear results showed that the wear resistance of the composites was significantly higher than that of the matrix alloy due to the increase in hardness as well as reduction in the size and also morphology transformation of eutectic silicon with increase in SiCp content. However, the existence of particle-porosity clustering with increasing the SiCp content to 25 wt% played a significant role in deteriorating the wear behavior of the composite
Characteristics of Mineral Oil-based Nanofluids for Power Transformer Application
Trends in the field of nanomaterial-based transformer oil show most of the conducted works have focused only on the transformer oil-based nanofluids but limited studies on the stability of transformer oil-based nanofluids. Since mineral oil-based nanofluids still can produce the sedimentation, thus the cold-atmospheric pressure plasma method is proposed to functionally modify the Silicon Dioxide (SiO2) nanofiller in order to enhance the electrical properties of the mineral oil-based nanofluids. The AC breakdown strength oil samples before and after modification were measured. It was found that the plasma treated nanofluids have higher AC breakdown voltage compared to pure oil and untreated nanofluids. Also, Fourier Transform Infrared (FTIR) Spectroscopy has been used in this study to analyse the physical changes of oil samples. It is envisaged that the added silica nanofiller has significant effect on electrical properties of the transformer oil-based nanofluids which would enable to the development of an improved class of liquid dielectric for the application of power transformer
Reduced graphene oxide-multiwalled carbon nanotubes hybrid film with low Pt loading as counter electrode for improved photovoltaic performance of dye-sensitised solar cells
In this work, the role of reduced graphene oxide (rGO) with hyperbranched surfactant and its hybridisation with multiwalled carbon nanotubes (MWCNTs) and platinum (Pt) nanoparticles (NPs) as counter electrode (CE) were investigated to determine the photovoltaic performance of dye-sensitised solar cells (DSSCs). Sodium 1,4-is(neopentyloxy)-3-(neopentyloxycarbonyl)- 1,4-dioxobutane-2-sulphonate (TC14) surfactant was utilised as dispersing and stabilising agent in electrochemical exfoliation to synthesise graphene oxide (GO) as initial solution for rGO production prior to its further hybridisation and fabrication as thin film. A chemical reduction process utilising hydrazine hydrate was conducted to produce rGO due to the low temperature
process and water-based GO solution. Subsequently, hybrid solution was prepared by mixing 1 wt% MWCNTs into the produced rGO solution. TC14-rGO and TC14-rGO_MWCNTs hybrid solution were transferred into fluorine-doped tin oxide substrate to fabricate thin film by spraying deposition method. Finally, the CE films were prepared by coating with thin Pt NPs. Photoanode film was prepared by a two-step process: hydrothermal growth method to synthesise titanium dioxide
nanowires (TiO2 NWs) and subsequent squeegee method to apply TiO2
NPs. According to solar simulator measurement, the highest energy conversion efficiency (η) was achieved by using CE-based TC14-rGO_MWCNTs/Pt (1.553%), with the highest short current density of 4.424 mA/cm2. The highest η was due to the high conductivity of CE hybrid film and the morphology of fabricated TiO2 NWs/TiO2 NPs. Consequently, the dye adsorption was high, and the photovoltaic performance of DSSCs was increased. This result also showed that rGO and rGO_MWCNTs hybrid can be used as considerable potential candidate materials to replace Pt gradually
Crosswind Shear Gradient Affect on Wake Vortices
Parametric simulations with a Large Eddy Simulation (LES) model are used to explore the influence of crosswind shear on aircraft wake vortices. Previous studies based on field measurements, laboratory experiments, as well as LES, have shown that the vertical gradient of crosswind shear, i.e. the second vertical derivative of the environmental crosswind, can influence wake vortex transport. The presence of nonlinear vertical shear of the crosswind velocity can reduce the descent rate, causing a wake vortex pair to tilt and change in its lateral separation. The LES parametric studies confirm that the vertical gradient of crosswind shear does influence vortex trajectories. The parametric results also show that vortex decay from the effects of shear are complex since the crosswind shear, along with the vertical gradient of crosswind shear, can affect whether the lateral separation between wake vortices is increased or decreased. If the separation is decreased, the vortex linking time is decreased, and a more rapid decay of wake vortex circulation occurs. If the separation is increased, the time to link is increased, and at least one of the vortices of the vortex pair may have a longer life time than in the case without shear. In some cases, the wake vortices may never link
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