Influence of Changes of Land Cover Types on The Surface Temperature Distribution for Al- Najaf City Using Remote Sensing Data.

This study has been carried out to assesses the relationship between land surface temperatures (LST) and changes of land cover (LC) for a part of Najaf Governorate, by using Landsat TM/ETM+ data over the period from1990 to 2009. Landsat TM/ETM+ images have been acquired for deriving the land use/land cover (LULC) maps and land surface temperatures (LST) for two different dates afterwards analysis their temporal and spatial variations. (LST) maps have been derived from thermal infrared (TIR) bands of Landsat TM/ETM+ data according to Plancks function. Satellite images for 1990, and 2009 have been classified into four classes (building up, vegetation, bare land, and water bodies) based on the supervised classification by using Maximum Likelihood algorithm. Normalized Difference Vegetation Index (NDVI) and Normalized Difference Built-up Index (NDBI) have been calculated from both the original image in order to extract a particular (LC) for study area. The results of study showed that built-up area increased from 22.1% to 41.8 % between 1990 and 2009, while vegetations, bare land and water bodies decreased from 57.5% to 39.9% , 16.9% to 15.3% , and 3.5% to 3% respectively , due to urbanization that resulted from growing of urban population and economic evolution, . In general the negative correlation between LST and NDVI confirm that the reduction in vegetarian cover to built-up would lead to increase in (LST). Whereas the positive correlation between LST and NDBI implying that the increasing built-up land can increase (LST). The results indicated that the stronger negative correlations between LST and NDVI (R2=0.918) was in 2009 year , and the stronger positive correlation between LST and NDBI (R2=0.909) was in 2009. The results showed that the maximum temperature in study area increased from 32 áµ’C in 1990 to 37áµ’C in 1990 .This research has been confirmed the strong influence of changes in (LC) on (LST)

Étude de la stabilité thermique et protection à la surcharge de cathodes pour batteries au lithium-ion

Dans cette thèse, nous avons effectué une étude de la stabilité thermique de quelques matériaux, utilisés comme cathodes dans les batteries au lithium-ion (BLIs), afin de contribuer à l’amélioration de leur fonctionnement. Deux matériaux, potentiellement prometteurs pour les applications d’envergure des BLIs – telles que les véhicules électriques –, ont été choisis pour cette étude. Il s’agit du phosphate de fer lithié (LiFePO4) et de l’oxyde de nickel et de manganèse de structure-type spinelle (LiMn1.5Ni0.5O4). En plus de l’étude du mécanisme de décomposition de ce dernier, l’effet de la substitution partielle du manganèse dans le matériau original (LiMn2O4) par du nickel sur la réactivité a été mise en évidence. Ces études ont été menées grâce à la calorimétrie adiabatique afin de simuler les conditions thermiques retrouvées dans des BLIs où l’environnement est quasi-adiabatique. L’effet de trois méthodes de synthèse sur la réactivité a été examiné pour LiFePO4. Nos résultats ont montré que, contrairement aux autres matériaux de cathodes, la stabilité thermique globale de LiFePO4 est peu affectée par la méthode de synthèse. Toutefois, cette stabilité intrinsèque dont le LiFePO4 bénéficie ne le met pas à l’abri des conditions d’abus de source externes. Ainsi, nous avons développé une nouvelle classe d’additifs électrolytiques pour la protection de LiFePO4 contre la surcharge. Ces derniers consistent en l’incorporation d’une navette redox dans un liquide ionique; tirant ainsi profit des avantages des deux espèces. Notre approche nous a permis d’atteindre une concentration aussi élevée qu’une mole par litre de notre additif dans des électrolytes conventionnels. Nous avons montré qu’à une concentration optimale de 0.7 M, ces liquides ioniques fonctionnalisés ont assuré la protection de LiFePO4 contre la surcharge pour plus de 200 cycles; et ce, sans affecter ses performances électrochimiques. Finalement, pour ce qui est du deuxième matériau de cathode, nous avons établi un mécanisme de décomposition de LiMn1.5Ni0.5O4 à hautes températures en présence de l’électrolyte. En plus, notre étude a montré que la substitution partielle du manganèse par le nickel dans LiMn2O4 pour augmenter son potentiel opérationnel a affecté à la baisse sa stabilité thermique; et ce, à des températures aussi basses que 60 °C.In this thesis, we have investigated the thermal stability of cathode materials used in lithium-ion batteries (LIBs). Using accelerating rate calorimetry, the study was carried out on two of the most attractive cathode materials for large scale LIBs; namely, lithium iron phosphate (LiFePO4) and nickel-manganese spinel oxide (LiMn1.5Ni0.5O4). While the impact of partial nickel substitution for manganese in LiMn2O4 was investigated for LiMn1.5Ni0.5O4 along with its decomposition mechanism, the effect of the synthetic method was evaluated for LiFePO4. Our results have demonstrated that the high intrinsic thermal stability of LiFePO4 was only slightly affected by the synthetic method within the three studied routes. In order to enhance the safe operation of this material by providing a protection form electrical abuse during overcharge, we have developed a new class of overcharge protection additives. By combining a redox shuttle with an ionic liquid, we were able, for the first time, to dissolve the additive for protection against overcharge at concentrations up to 1 M in conventional electrolytes for LIBs. Our results have shown an overcharge protection of LiFePO4 for over 200 cycles, using an optimal concentration of 0.7 M, without compromising its electrochemical performances. Finally, by studying the thermal behavior of LiMn1.5Ni0.5O4 at different temperatures, we were able to establish the decomposition mechanism of this material. Moreover, our study has proven that the presence of nickel in LiMn1.5Ni0.5O4, that ensures the high voltage of this cathode material, is also responsible for the very poor thermal stability of this material at temperatures as low as 60 ºC

PERSEPSI MAHASISWA TERHADAP ETIKA AKUNTAN PENDIDIK (STUDI EMPIRIS PADA FAKULTAS EKONOMI DAN BISNIS UNIVERSITAS HASANUDDIN)

2014Persepsi Mahasiswa terhadap Etika Akuntan Pendidik \ud (Studi Empiris Pada Fakultas Ekonomi dan Bisnis \ud Universitas Hasanuddin) \ud \ud Muhammad Khakani Harusi \ud Hj. Kartini \ud M. Achyar Ibrahim \ud Penelitian ini bertujuan untuk mengetahui bagaimana persepsi Mahasiswa \ud terhadap Etika Akuntan Pendidik. Pengambilan sampel penelitian \ud dilakukan di Universitas Hasanuddin yakni Mahasiswa-Mahasiswi Fakultas \ud Ekonomi dan Bisnis. \ud Dari hasil penentuan sampel dengan menggunakan metode Slovin, maka \ud sampel yang digunakan ialah sebanyak 79 responden, kemudian data dari \ud hasil kuesioner yang dibagikan sebagai metode operasionalisasi konsep \ud agar menjadi konstruk dianalisis secara deskriptif yakni dengan melihat \ud nilai mean/rata-rata. Hasil analisis menunjukkan rata-rata terkecil sebesar \ud 3,6456 dan terbesar 4,4430. Angka tersebut menunjukkan bahwa \ud Mahasiswa-Mahasiswi Fakultas Ekonomi menganggap bahwa Etika \ud Akuntan Pendidik dalam hal ini dosen cenderung baik dan telah mengikuti \ud delapan prinsip etika akuntan, walaupun masih ada sebagian kecil \ud akuntan pendidik yang ditanggapi ragu etikanya oleh responden. \ud \ud Kata Kunci: Persepsi Mahasiswa, Etika Akuntan Pendidik, Prinsip Etika Akunta

Softening of the insulating phase near Tc for the photo-induced insulator-to-metal phase transition in vanadium dioxide

We use optical-pump terahertz-probe spectroscopy to investigate the near-threshold behavior of the photoinduced insulator-to-metal (IM) transition in vanadium dioxide thin films. Upon approaching Tc a reduction in the fluence required to drive the IM transition is observed, consistent with a softening of the insulating state due to an increasing metallic volume fraction (below the percolation limit). This phase coexistence facilitates the growth of a homogeneous metallic conducting phase following superheating via photoexcitation. A simple dynamic model using Bruggeman effective medium theory describes the observed initial condition sensitivity.Comment: accepted for publication in Physical Review Letter

Pulsed-laser-ablation based nanodecoration of multi-wall-carbon nanotubes by Co–Ni nanoparticles for dye-sensitized solar cell counter electrode applications

Abstract We report here on the use of pulsed KrF-laser deposition technique (PLD) for the decoration of Multi-wall carbon nanotubes (MWCNTs) by Co–Ni nanoparticles (NPs) to form highly efficient counter electrodes (CEs) for use in Dye-sensitized solar cells (DSSC). By varying the number of laser ablation pulses (N LP = 500–60,000) of the KrF laser, we were able to control the average size of the Co–Ni NPs and the surface coverage of the MWCNTs by the nanoparticles. The PLD-based decoration of MWCNTs by Co–Ni NPs is shown to form novel counter electrodes, which significantly enhance the power conversion efficiency (PCE) of the DSSCs. Indeed, the DSSCs based on the PLD-decorated Co–Ni counter electrodes (obtained at the optimal N LP = 40,000) are shown to exhibit a PCE value as high as 6.68%, with high short circuit current (J sc = 14.68 mA/cm2) and open circuit voltage (V oc = 0.63 V). This represents a PCE improvement of ~190% in comparison to the DSSCs with pristine MWCNTs (PCE = 2.3%) and ~7.4% PCE increase than that of the conventional DSSC made with a sputtered Platinum-based counter electrode. By systematically investigating the local nanostructure of the Co–Ni decorated CEs, we found that the Co–Ni NPs layer exhibits a porous cauliflower-like morphology, of which surface roughness (RMS) is N LP dependent. Interestingly, both PCE and roughness of the Co–Ni NPs layer are found to exhibit the same N LP dependence, with a maximum located around the optimal N LP value of 40,000. This enabled us to establish, for the first time, a linear correlation between the achieved PCE of DSSCs and the local roughness of their CEs decorated by Co–Ni NPs. Such a correlation highlights the importance of maximizing the surface area of the Co–Ni coated MWCNTs on the CEs to enhance the PCE of the DSSCs. Finally, Ultra-violet Photoelectron Spectroscopy (UPS) measurements revealed a significant decrease in the local work function (Φ) of Co–Ni NPs decorated MWCNTs based CEs (at N LP = 40,000, Φ = 3.9 eV) with respect to that of either pristine MWCNTs (Φ = 4.8 eV) or sputtered-Pt (Φ = 4.3 eV) counter-electrodes. This Φ lowering of the Co–Ni/MWCNTs based CEs is an additional advantage to enhance the catalytic reaction of the redox couple of the electrolyte solution, and improve thereby the PCE of the DSSCs

Influence of solution parameters for the fast growth of ZnO nanostructures by laser-induced chemical liquid deposition

ZnO nanorods, nanoneedles, nanoparticles and nanoballs were synthesized on fused quartz substrates upon irradiation of a droplet of methanolic zinc acetate dihydrate solution by an infrared continuous wave CO₂ laser for a few seconds. The addition of monoethanolamine and water to the solution improved the alignment of the nanorods and had a significant effect on the volume and morphology of the deposits. An increase of the zinc acetate concentration was found to lead to an increase of the thickness and area covered by the initial ZnO seed layer on which the nanostructures grew. By investigating the crystal structure of the deposits using x-ray and electron diffraction, we were able to show that the nanorods grow along the c axis with a high crystalline quality. Raman and photoluminescence spectroscopy confirmed the high-quality of the grown ZnO nanostructures. As a matter of fact, their photoluminescence spectra are dominated by an intense UV emission around 390 nm

Preparation and mechanical characterization of laser ablated single-walled carbon-nanotubes/polyurethane nanocomposite microbeams

We report on the preparation of nanocomposites consisting of laser synthesized single-walled carbon nanotubes (C-SWNTs) reinforcing a polyurethane. Prior to their incorporation into the polymer matrix, the C-SWNTs were purified, and characterized by means of various techniques. The purification in nitric acid added carboxylic groups to the C-SWNTs. A procedure to properly disperse the nanomaterials in the polymer was developed involving high shear mixing using a three-roll mill and a non-covalent functionalization of the nanotubes by zinc protoporphyrin IX molecule. The incorporation of the C-SWNTs into the resin led to an increase of the viscosity and the apparition of a slight shear-thinning behavior. A further increase of the shear-thinning behavior using fumed silica particles enabled the direct-write fabrication of microbeams. Mechanical characterization revealed significant increase in both strength (by ∼64%) and modulus (by more than 15 times). These mechanical enhancements are believed to be a consequence of the successful covalent and the non-covalent functionalizations of the nanotubes

A Macroscopic and Microscopic Study of Liver in Female Iraqi Green Freshwater Turtle (Chelonia mydas) Linnaeus,1758 during the Active Period

The study aims to provide anatomical and histological information about the liver in female Iraqi green freshwater turtles. Ten female green freshwater turtles (Chelonia mydas) were collected from Shatt Al-Hilla and used in this study. They were anesthetized by chloroform in closed chambers. The anatomical information was recorded and the histological sections of the liver were stained by using hematoxylin and Eosin stains. The result showed that the liver of a female green freshwater turtle (Chelonia mydas) is a large elongated organ. The mean weight of turtles is 735±0.04 gm, and the mean weight of the liver is 28±0.02 gm. The ratio between the weight of the liver to the weight of the body was 3.809 %. The liver of (Chelonia mydas) is formed from three lobes right, left and middle (central) lobes. The right lobe is the large one with an average weight of 13 ±0.022 gm.  It looks like a square and has two surfaces ventral and dorsal (visceral) surface. The left lobe is smaller than the right with an average weight of 9±0.05gm, and its shape is rectangular. The middle lobe is rounded and small. Its mean weight is 7±0.01gm. Histologically, the liver is covered by mesothelium under its connective tissue layer as a hepatic capsule which divided the liver into lobules in the shape of hexagons with portal spaces, from the central to the walls of the hepatocyte

Electrical transport properties of single wall carbon nanotube/polyurethane composite based field effect transistors fabricated by UV-assisted direct-writing technology

We report on the fabrication and transport properties of single-walled carbon nanotube (SWCNT)/polyurethane (PU) nanocomposite microfiber-based field effect transistors (FETs). UV-assisted direct-writing technology was used, and microfibers consisting of cylindrical micro-rods, having different diameters and various SWCNT loads, were fabricated directly onto SiO₂/Si substrates in a FET scheme. The room temperature dc electrical conductivities of these microfibers were shown to increase with respect to the SWCNT concentrations in the nanocomposite, and were about ten orders of magnitude higher than that of the pure polyurethane, when the SWCNT load ranged from 0.1 to 2.5 wt% only. Our results show that for SWCNT loads ≤ 1.5 wt%, all the microfibers behave as a FET with p-type transport. The resulting FET exhibited excellent performance, with an I on/I off ratio of 105 and a maximum on-state current (I on) exceeding 70 µA. Correlations between the FET performance, SWCNTs concentration, and the microfiber diameters are also discussed