Using Density Functional Theory to Model Realistic TiO2 Nanoparticles, Their Photoactivation and Interaction with Water

Computational modeling of titanium dioxide nanoparticles of realistic size is extremely relevant for the direct comparison with experiments but it is also a rather demanding task. We have recently worked on a multistep/scale procedure to obtain global optimized minimum structures for chemically stable spherical titania nanoparticles of increasing size, with diameter from 1.5 nm (~300 atoms) to 4.4 nm (~4000 atoms). We use first self-consistent-charge density functional tight-binding (SCC-DFTB) methodology to perform thermal annealing simulations to obtain globally optimized structures and then hybrid density functional theory (DFT) to refine them and to achieve high accuracy in the description of structural and electronic properties. This allows also to assess SCC-DFTB performance in comparison with DFT(B3LYP) results. As a further step, we investigate photoexcitation and photoemission processes involving electron/hole pair formation, separation, trapping and recombination in the nanosphere of medium size by hybrid DFT. Finally, we show how a recently defined new set of parameters for SCC-DFTB allows for a proper description of titania/water multilayers interface, which paves the way for modeling large realistic nanoparticles in aqueous environment

Native surface oxide turns alloyed silicon membranes into nanophononic metamaterials with ultra-low thermal conductivity

A detailed understanding of the relation between microscopic structure and phonon propagation at the nan oscale is essential to design materials with desired phononic and thermal properties.Here we uncover a new mechanism of phonon interaction in surface oxidized membranes, i.e., native oxide layers interact with phonons in ultra-thin silicon membranes through local resonances. The local resonances reduce the low frequency phonon group velocities and shorten their mean free path. This effect opens up a new strategy for ultralow thermal conductivity design as it complements the scattering mechanism which scatters higher frequency modes effectively. The combination of native oxide layer and alloying with germanium in concentration as small as 5% reduces the thermal conductivity of silicon membranes to 100 time lower than the bulk. In addition, the resonance mechanism produced by native oxide surface layers is particularly effective for thermal condutivity reduction even at very low temperatures, at which only low frequency modes are populated.Comment: 6 pages, 5 figures, Accepted for publication in Physical Review

Pengaruh Strategi Kompetitif Terhadap Hubungan Sistem Pengendalian Akuntansi Dengan Kinerja Perusahaan

This study aims to determine the effect of competitive strategy for relations accounting control system with the company's performance in the hotel company located in the city of Palembang. The sampling technique in this research is purposive sampling in order to obtain a sample of 42 top managers. Hypothesis testing using methods sub-groups. The tools used to analyze the data using IBM SPSS 17. Results of testing the hypothesis states that a competitive strategy has influence on relations accounting control system to corporate performance

Development landscape language as tourist attraction in the area destination tour Regency Humbang Hasundutan

Developing landscape language is something effort important in strengthen identity culture something area destination tour. Regency Humbang Hasundutan, a region in Indonesia which is rich in diversity culture and nature, have potency big for developed become objective interesting tour. However, one necessary aspect noticed in development destination tour is diversity language in the area the Study This aim for analyze and identify diversity language in the District Humbang Hasundutan as well as develop a development strategy landscape language that can support development destination tour. Method study This using interactive models in form qualitative. Research results found: first, still There is object tours in the area destination tour Regency Humbang Hasundutan yet complete landscape language so that lack of information landscape object language tour the. Development landscape language need be equipped start from landscape language Happy come to tourist are, landscape language pointer direction to location object travel, landscape language Happy comeacross the object travel, landscape language folk and landscape discourse language description empirical or geographic with implement this strategy, it is expected Regency Humbang incitement can maintain and develop diversity language as assetvaluable culture. Development landscape strong language will give contribution positive for development destination travel, increase Power pull travel and deliver experience different to visitor. Besides that, development landscape language willgive benefit social, like strengthen identity culture public local and push participation public in development tourist in a manner sustainable

Penyesuaian diri pasangan suami istri yang menikah melalui proses ta’arufdikalangan kader pks di kota Binjai

Tujuan penelitian ini adalah untuk mengetahui proses penyesuaiandiri pada pasangan suami istri yang melakukan pernikahan melalui proses ta’aruf, problematika pasangan suami istri setelah menikah dan persepsi kader PKS mengenai pernikahan melalui proses ta’aruf. Untuk memperoleh data yang diperlukan dalam penelitian ini, peneliti menggunakan pendekatan kualitatif dalam bentuk deskriptif. Subjek pada penelitian ini yaitu pasangan suami istri yang melakukan pernikahan melalui proses ta’aruf. Tekhnik yang digunakan untuk mengumpulkan data adalah wawancara,Observasi pasrtisipan dan dokumentasi. Teknik analisis yang digunakan adalah menggambarkan sirkulasi terjadi antara pengumpulan data, penyajian data, reduksi data dan kesimpulan-kesimpulan semuanya dilakukakan dalam proses yang terpisah. Temuan penelitian ini bahwa penyesuaian diri setelah menikah, suami dan istri akan menemukan banyak masalah dalam pernikahan mereka mulai dari masalah antara suami dan istri sampai dengan masalah keluarga dengan lingkungan sekitarnya. Penyesuaian diri dalam pernikahan yang dilakukan oleh suami dan istri adalah dengan melakukan penyesuaian diri satu sama lain yaitu melakukan penyesuaian dengan pasangan, penyesuaian keuangan dan penyesuaian dengan keluarga dari pihak pasangan. Hasil yang dicapai dalam penyesuaian diri pasangan suami istri yang melakukan pernikahan melalui proses ta’arufdi kalangan kader PKS adalah bahwa subjek tersebut sama-sama tidak sulit untuk menyesuaiakan diri dengan pasangan. Karena sebelumnya mereka sudah berta’aruf melalui media murobbi dan proposal, walaupun tidak semua informasi mereka dapat.Namun dengan niat yang baik dan karena Allah SWT, semua seakan dimudahkan Allah.Hanya saja mereka sulit penyesuaiakan diri terhadap karakter masing-masing pasangan. Problematika yang terjadi saat menikah ialah saat komunikasi dan butuh waktu yang lama untuk memahami karakter masing-masing pasanga

Novel metastable metallic and semiconducting germaniums

By means of ab initio metadynamics runs we explored the lower-pressure region of the phase diagram of germanium. A monoclinic germanium phase with four-membered rings, less dense than diamond and compressible into \beta-tin phase (tI4) was found. A metallic bct-5 phase, mechanically stable down to room conditions appeared between diamond and tI4. mC16 is a narrow-gap semiconductor, while bct-5 is metallic and potentially still superconducting in the very low pressure range. This finding may help resolving outstanding experimental issues.Comment: 6 figure

Structure Property and Prediction of Novel Materials using Advanced Molecular Dynamics Techniques: Novel Carbons, Germaniums and High-Performance Thermoelectrics

By means of advanced molecular dynamic techniques, we predict the stability of novel materials based on carbon, germanium and PbSe. This topological solutions have been studied and characterised at a DFT/DFTB level of theory and interesting optical, mechanical, electronic and heat transport properties have been pointed out

BGA footprints modeling and physics based via models validation for power and signal integrity applications

Modeling and simulating the multi-scale nature of a power distribution network (PDN) is essential to ensure the correct functioning of the devices connected to it. Simple parallel-plate sections constitute the core of these PDN geometries, together with sections where a large number of holes and vias are present, as in the case of a BGA footprint. Employing a divide-and-conquer approach allows for the modeling of these geometries separately, i.e., 3-D full wave solvers for the sections with holes and vias, and a cavity model approach, for the simple parallel-plate structures. Also, equivalent circuit models can be obtained for time-domain and frequency-domain SPICE simulations --Abstract, page iv

Evaluation of antioxidant and anti-inflammatory effects of red raspberries on chronic nicotine-induced damage: an experimental study

Background: As an addictive substance, nicotine has been recognized as a risk factor to induce oxidative tissue damage, which is a main risk factor for development of lung-related diseases.  Red raspberries (Rubus idaeus L.) have been used for the treatment of several tissue damage for decreasing oxidative stress and inflammation. For this purpose, authors aimed to investigate the antioxidant and anti-inflammatory effects of raspberry on nicotine-induced lung damage in rats.Methods: 32 male Sprague–Dawley rats included in present study. The rats were divided into the following four groups, with eight rats in each group: control, raspberry 100 mg/kg, nicotine 5 mg/kg, nicotine + raspberry 100 mg/kg treated (concomitant nicotine and raspberry extract) groups. The assessment of lung structure was made on light and stereo investigator microscope, immunohistochemical analysis was performed by determining anti-Caspase-3 immunostaining.Results: The lung of the nicotine applied group exhibited emphysematous air spaces, massive congestion areas, disrupted alveoli, thickened septa and inflammatory cell infiltration. Much improvement was observed in the raspberry-treated group despite the presence of mild residual changes. Moreover, loss of massive congestion areas and decreased Caspase-3 level were detected in the raspberry-treated group.Conclusions: Our results indicate that the raspberry extract attenuate the pathological changes of nicotine in the lung rats through antioxidative and anti- inflammatory mechanisms