3,677 research outputs found
On the thermoelastic analysis of solar cell arrays and related material properties
Accurate prediction of failure of solar cell arrays requires accuracy in the computation of thermally induced stresses. This was accomplished by using the finite element technique. Improved procedures for stress calculation were introduced together with failure criteria capable of describing a wide range of ductile and brittle material behavior. The stress distribution and associated failure mechanisms in the N-interconnect junction of two solar cell designs were then studied. In such stress and failure analysis, it is essential to know the thermomechanical properties of the materials involved. Measurements were made of properties of materials suitable for the design of lightweight arrays: microsheet-0211 glass material for the solar cell filter, and Kapton-H, Kapton F, Teflon, Tedlar, and Mica Ply PG-402 for lightweight substrates. The temperature-dependence of the thermal coefficient of expansion for these materials was determined together with other properties such as the elastic moduli, Poisson's ratio, and the stress-strain behavior up to failure
One-Mother Vertex Graphs
In this paper we will define a new type of graph. The idea of this definition
is based on when we illustrate the cardiovascular system by a graph we find that not all vertices have the same important so we define this new graph and call it 1- mother vertex graph
Satellite estimates of wide-range suspended sediment concentrations in Changjiang (Yangtze) estuary using MERIS data
The Changjiang (Yangtze) estuarine and coastal waters are characterized by suspended sediments over a wide range of concentrations from 20 to 2,500 mg l-1. Suspended sediment plays important roles in the estuarine and coastal system and environment. Previous algorithms for satellite estimates of suspended sediment concentration (SSC) showed a great limitation in that only low to moderate concentrations (up to 50 mg l-1) could be reliably estimated. In this study, we developed a semi-empirical radiative transfer (SERT) model with physically based empirical coefficients to estimate SSC from MERIS data over turbid waters with a much wider range of SSC. The model was based on the Kubelka–Munk two-stream approximation of radiative transfer theory and calibrated using datasets from in situ measurements and outdoor controlled tank experiments. The results show that the sensitivity and saturation level of remote-sensing reflectance to SSC are dependent on wavelengths and SSC levels. Therefore, the SERT model, coupled with a multi-conditional algorithm scheme adapted to satellite retrieval of wide-range SSC, was proposed. Results suggest that this method is more effective and accurate in the estimation of SSC over turbid water
Can neutral and ionized PAHs be carriers of the UV extinction bump and the diffuse interstellar bands?
Up to now, no laboratory-based study has investigated polycyclic aromatic
hydrocarbon (PAH) species as potential carriers of both the diffuse
interstellar bands (DIBs) and the 2175 A UV bump. We examined the proposed
correlation between these two features by applying experimental and theoretical
techniques on two specific medium-sized/large PAHs (dibenzorubicene C30H14 and
hexabenzocoronene C42H18) in their neutral and cationic states. It was already
shown that mixtures of sufficiently large, neutral PAHs can partly or even
completely account for the UV bump. We investigated how the absorption bands
are altered upon ionization of these molecules by interstellar UV photons. The
experimental studies presented here were realized by performing matrix
isolation spectroscopy with subsequent far-UV irradiation. The main effects
were found to be a broadening of the absorption bands in the UV combined with
slight red shifts. The position of the complete pi - pi* absorption structure
around 217.5 nm, however, remains more or less unchanged which could explain
the observed position invariance of the interstellar bump for different lines
of sight. This favors the assignment of this feature to the interstellar PAH
population. As far as the DIBs are concerned, neither our investigations nor
the laboratory studies carried out by other research groups support a possible
connection with this class of molecules. Instead, there are reasonable
arguments that neutral and singly ionized cationic PAHs cannot be made
responsible for the DIBs.Comment: 11 pages, 7 figures, 1 tabl
The solution of mixed integral equation of the first kind using toeplitz matrix method
In this work, the existence and uniqueness of the solution of mixed integral equation (MIE) of the first kind is considered in the L2 *C[0,T], T<1 , is the domain of integration with respect to position and T is the time. Then, a numerical method is used to obtain a system of Fredholm integral equations (SFIE). The discontinuous kernel of the SFIE takes the form of Carleman function and logarithmic kernel. The existence and uniqueness of the solution SFIE can be proved. Moreover, Toeplitz matrix method (TMM) is used to obtain a linear algebraic system (LAS). The LAS is solved numerically, to get the eigenvalues and eigenfunctions of SFIE
Ending Neglect of older people in the response to Humanitarian Emergencies
Older people make up a significant and growing number of those affected by humanitarian crises, yet they are often not sought out or prioritised within the humanitarian response. Humanitarian agencies, donors, and international bodies neglect older people's health and nutrition. The gaps in knowledge and research about the needs of older people in emergencies are considerable. Older people are not monitored in emergencies and they are not prioritised despite evidence of disproportionate mortality and morbidity in this group. We call for policy changes by humanitarian agencies and donors to ensure that the needs of this vulnerable group are met
The 2.5-5.0 micron spectra of Io: Evidence for H2S and H2O frozen in SO2
The techniques of low temperature spectroscopy are applied to identify the constituents of the ices covering the surface of Io, a satellite of Jupiter. Infrared spectra of Io in the 4000-2000 cm exp -1 region, including new observational data, are analyzed using laboratory studies of plausible surface ices
Photoinduced Fluorescence from the Perylene Cation Isolated in Ne and Ar Matrices
The fluorescence and fluorescence excitation spectra of the perylene cation isolated in neon and argon matrices are reported. This is the first report of the fluorescence spectrum of a polycyclic aromatic hydrocarbon ion in any phase
Ethoxyquin Inhibits the Progression of Murine Ehrlich Ascites Carcinoma through the Inhibition of Autophagy and LDH
Cancer cells exhibit an increased glycolysis rate for ATP generation (the Warburg effect) to sustain an increased proliferation rate. In tumor cells, the oxidation of pyruvate in the Krebs cycle is substituted by lactate production, catalyzed by LDH. In this study, we use ethoxyquin (EQ) as a novel inhibitor to target LDH in murine Ehrlich ascites carcinoma (EAC) and as a combination therapy to improve the therapeutic efficacy of the conventional chemotherapy drug, cisplatin (CIS). We investigated the anti-tumor effect of EQ on EAC-bearing mice and checked whether EQ can sustain the anti-tumor potential of CIS and whether it influences LDH activity. Treatment with EQ had evident anti-tumor effects on EAC as revealed by the remarkable decrease in the expression of the anti-apoptotic gene Bcl-2 and by a significant increase in the expression of apoptotic genes (BAX and caspase-3). EQ also caused a significant decrease in the autophagic activity of EAC cells, as shown by a reduction in the fluorescence intensity of the autophagosome marker. Additionally, EQ restored the altered hematological and biochemical parameters and improved the disrupted hepatic tissues of EAC-bearing mice. Co-administration of EQ and CIS showed the highest anti-tumor effect against EAC. Collectively, our findings propose EQ as a novel inhibitor of LDH in cancer cells and as a combinatory drug to increase the efficacy of cisplatin. Further studies are required to validate this therapeutic strategy in different cancer models and preclinical trials
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