Gravitational Wave Astrometry for Rapidly Rotating Neutron Stars and Estimation of Their Distances

We discuss an astrometric timing effect on data analysis of continuous gravitational waves from rapidly rotating isolated neutron stars. Special attention is directed to the possibility of determining their distances by measuring the curvature of the wave fronts. We predict that if continuous gravitational waves from an unknown neutron star with a stable rotation are detected around 1kHz within 1/3yr by initial LIGO detectors and the ellipticity parameter epsilon is smaller than 10^{-6}, the distance r to the source can be estimated with relative error \Delta r/r of \sim 10% by using the broad band configuration of advanced LIGO detectors over 3 years. By combining the observed amplitude of the waves with the estimated distance, information on the parameter $\epsilon$ can be obtained purely through gravitational wave measurements.Comment: 6 pages, 1 figure, to appear in PR

Komposisi Dan Kelimpahan Gastropoda Di Vegetasi Mangrove Kelurahan Tugurejo, Kecamatan Tugu, Kota Semarang

Mangrove forest is one of the unique natural ecosystems with high productivity. That comes from organic detritus or litter fall which is essential nutrient sources for organism souch as fish and inverterbrates, one of which is gastropod. The purpose of this study was to determine the composition and abundance of gastropods found in mangrove vegetation Tugurejo Village, District Tugu, Semarang. This study was conducted in September 2011-March 2012. This study material is all gastropods found at the sites. Research consists of 4 stations and samples were taken with using transek (1 x 1) m2 in 3 sub stations. The research revealed that there were 11 species of gastropod belonged to 3 families, i.e. C.rithidea cingulata cingulata, Cerithidea sp.1, Cerithidea sp.2, C. quadrata, T. telescopium, Terebralia palustris (Potamididae), Littorina articulata, L. carinifera, Littorina pallescense (Littorinidae), and Sphaerassiminea miniata (Assiminidae). The species most frequently found was C. cingulata cingulata and T. telescopium. While most species rarely found is C. quadrata. The highest abundance average value was found at Station C which was dominated by Avicennia marina. The diversity index (H ') at Station A and B was low, while at Station C and D was moderate. The Uniformity Index (e) at Station A and B was low but at Station C and D was high and moderate. There was species dominance is Cerithidea cingulata cingulata at Station C

Loop quantum gravity effects on inflation and the CMB

In loop quantum cosmology, the universe avoids a big bang singularity and undergoes an early and short super-inflation phase. During super-inflation, non-perturbative quantum corrections to the dynamics drive an inflaton field up its potential hill, thus setting the initial conditions for standard inflation. We show that this effect can raise the inflaton high enough to achieve sufficient e-foldings in the standard inflation era. We analyze the cosmological perturbations generated when slow-roll is violated after super-inflation, and show that loop quantum effects can in principle leave an indirect signature on the largest scales in the CMB, with some loss of power and running of the spectral index.Comment: revtex4, 5 pages, 3 figures, significant improvements in explanation of quantization and perturbation issues; version to appear Classical and Quantum Gravit

Twin wall of cubic-tetragonal ferroelastics

We derive solutions for the twin wall linking two tetragonal variants of the cubic-tetragonal ferroelastic transformation, including for the first time the dilatational and shear energies and strains. Our solutions satisfy the compatibility relations exactly and are obtained at all temperatures. They require four non-vanishing strains except at the Barsch-Krumhansl temperature TBK (where only the two deviatoric strains are needed). Between the critical temperature and TBK, material in the wall region is dilated, while below TBK it is compressed. In agreement with experiment and more general theory, the twin wall lies in a cubic 110-type plane. We obtain the wall energy numerically as a function of temperature and we derive a simple estimate which agrees well with these values.Comment: 4 pages (revtex), 3 figure

SINTESIS DAN KARAKTERISASI ORGANOCLAY SEBAGAI PENGUAT MATERIAL NANOKOMPOSIT BERBASIS LEMPUNG LOKAL

SINTESIS DAN KARAKTERISASI ORGANOCLAY SEBAGAI PENGUAT MATERIAL NANOKOMPOSIT BERBASIS LEMPUNG LOKAL. Riset pengembangan silika nanokomposit merupakan suatu awal dari tahapan menuju penguasaan nanoteknologi dalam rangka upaya meningkatkan daya saing produk lokal. Organoclay hasil sintesis dari bahan lempung montmorillonit alam Indonesia digunakan sebagai bahan dasar penyusun pembuatan material nanokomposit polimer yang akan diaplikasikan sebagai material komponen otomotif. Dalam penelitian ini telah dilakukan proses pembuatan organoclay dengan aktivasi asam menggunakan HCl dengan konsentrasi dan variasi waktu aktivasi tertentu yang kemudian ditambahkan surfaktan terpilih. Karakteristik morfologi organoclay hasil sintesis didapat dengan melakukan pengujian XRD, FT-IR, TGA dan dibandingkan karakteristiknya dengan organoclay bentone SD-1. Analisis terhadap spektrum FT-IR menunjukkan organoclay hasil sintesis maupun bentone SD-1 memiliki kemiripan yang tinggi untuk senyawa organik yang digunakan. Analisis terhadap Difraktometer XRD untuk organoclay hasil sintesis menunjukkan karakteristik instensitas serapan yang berbeda dengan clay alam dan terjadi peningkatan jarak antar lapis akibat interkalasi molekul organik yaitu dari semula 15,03 Å pada clay alam, akibat masuknya surfaktan pada antar lapis clay maka jarak antar lapisnya menjadi 39,18 Å untuk organoclay alam hasil sintesis. Dari analisis termogravimetri dapat disimpulkan organoclay hasil sintesis mulai mengalami kehilangan massa dalam jumlah yang cukup signifikan pada suhu 180 oC yang puncaknya pada suhu sekitar 220 oC. Total massa yang hilang pada proses tersebut hingga mencapai sekitar 30 %berat

Silicon-based resonant-cavity-enchanced photodiode with a buried SiO2 reflector

We report on a silicon-based resonant cavity photodiode with a buried silicon dioxide layer as the bottom reflector. The buried oxide is created by using a separation by implantation of oxygen technique. The device shows large Fabry-Perot oscillations. Resonant peaks and antiresonant troughs are observed as a function of the wavelength, with a peak responsivity of about 50 mA/W at 650 and 709 nm. The leakage current density is 85 pA/mm(2) at -5 V, and the average zero-bias capacitance is 12 pF/mm(2). We also demonstrate that the buried oxide prevents carriers generated deep within the substrate from reaching the top contacts, thus removing any slow carrier diffusion tail from the impulse response. (C) 1999 American Institute of Physics. (DOI: 10.1063/1.123499)

Measuring velocity of sound with nuclear resonant inelastic x-ray scattering

Nuclear resonant inelastic x-ray scattering is used to measure the projected partial phonon density of states of materials. A relationship is derived between the low-energy part of this frequency distribution function and the sound velocity of materials. Our derivation is valid for harmonic solids with Debye-like low-frequency dynamics. This method of sound velocity determination is applied to elemental, composite, and impurity samples which are representative of a wide variety of both crystalline and noncrystalline materials. Advantages and limitations of this method are elucidated

Accelerated Growth Plate Mineralization and Foreshortened Proximal Limb Bones in Fetuin-A Knockout Mice

PMCID: PMC3473050This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Search for Small-Mass Black Hole Dark Matter with Space-Based Gravitational Wave Detectors

The high sensitivity of upcoming space-based gravitational wave detectors suggests the possibility that if halo dark matter were composed of primordial black holes (PBHs) with mass between $10^{16}$ g and 10$^{20}$ g, the gravitational interaction with detector test masses will lead to a detectable pulse-like signal during the fly-by. For an improved version of the Laser Interferometer Space Antenna with a reduced acceleration noise at the low-end of its frequency spectrum, we find an event rate, with signal-to-noise ratios greater than 5, of $\sim$ a few per decade involving black holes of mass $\sim$ 10$^{17}$ g. The detection rate improves significantly for second generation space based interferometers that are currently envisioned, though these events must be distinguished from those involving perturbations due to near-Earth asteroids. While the presence of primordial black holes below a mass of $\sim$ 10$^{16}$ g is now constrained based on the radiation released during their evaporation, the gravitational wave detectors will extend the study of PBHs to a several orders of magnitude higher masses.Comment: 5 pages, 1 figur