The GEO 600 laser system

Interferometric gravitational wave detectors require high optical power, single frequency lasers with very good beam quality and high amplitude and frequency stability as well as high long-term reliability as input light source. For GEO 600 a laser system with these properties is realized by a stable planar, longitudinally pumped 12 W Nd:YAG rod laser which is injection-locked to a monolithic 800 mW Nd:YAG non-planar ring oscillator. Frequency control signals from the mode cleaners are fed to the actuators of the non-planar ring oscillator which determines the frequency stability of the system. The system power stabilization acts on the slave laser pump diodes which have the largest influence on the output power. In order to gain more output power, a combined Nd:YAGNd:YVO4 system is scaled to more than 22 W

Thermal performance analysis of a new structured-core translucent vacuuminsulation panel in comparison to vacuum glazing: Experimental and theoretically validated analyses

The notion at which, nowadays, building sector is being recognized to be nearly zero-energy buildings (NZEBs) relies partly on the thermal performance of its fabric insulation. Vacuum glazing (VG) technology attracted the research interest as an option to reduce heat loss through windows. However, the total glazing thermal transmittance (U-value) for VG increases with the use of smaller glazing area due to the edge-seal effects, due to the thermal short-circuit around the edges and the overall construction cost of VG leading to an unaffordable option to deal with energy conservation of buildings. Therefore, this study aims to propose a new structured core transparent vacuum insulation panel (TVIP) to accomplish insulation for the windows without edge sealing effect, with lower cost and can be easily retrofitted to the conventional windows of the existing buildings. To do this, VG and TVIP were constructed and their thermal conductivity were measured using heat flow meter apparatus. In addition, a 3D finite volume model considering the effect of surface to surface radiation, gas conduction, and thermal bridges through the spacer material and sealing material is developed. The model is validated with the experiments in this work and with the data for VG in the literature. The effect of vacuum pressure increase is simulated to mimic the vacuum deterioration problem and the effect of glazing size on the insulation performance of both VG and TVIP were investigated. The results indicate that for a smaller glazing area of less than 30 cm × 30 cm, the TVIP accomplished lower U-value compared with the VG at vacuum pressure of 0.1 Pa and 1 Pa. While, at a vacuum pressure of 10 Pa, the TVIP attained a lower U-value over the entire range of the investigated glazing sizes. Further, the edge-seal effect in the VG is diminished with the use of TVIP. Furthermore, the material cost per unit area of the TVIP is three times less than the cost of VG at laboratory scale. The results of the current study can guide vacuum window designers and researchers to further enhance the performance of TVIP based window to compete for the VG in the markets

Analytical expressions for the charge-charge local-field factor and the exchange-correlation kernel of a two-dimensional electron gas

We present an analytical expression for the static many-body local field factor $G_{+}(q)$ of a homogeneous two-dimensional electron gas, which reproduces Diffusion Monte Carlo data and embodies the exact asymptotic behaviors at both small and large wave number $q$. This allows us to also provide a closed-form expression for the exchange and correlation kernel $K_{xc}(r)$, which represents a key input for density functional studies of inhomogeneous systems.Comment: 5 pages, 3 figure

On UHECR energy estimation algorithms based on the measurement of electromagnetic component parameters in EAS

Model calculations are performed of extensive air shower (EAS) component energies using a variety of hadronic interaction parameters. A conversion factor from electromagnetic component energy to the energy of ultra-high energy cosmic rays (UHECRs) and its model and primary mass dependence is studied. It is shown that model dependence of the factor minimizes under the necessary condition of the same maximum position and muon content of simulated showers.Comment: contracted version is accepted for publication in Doklady Physic

Studi Tentang Aplikasi Kompos Ub Pada Pertumbuhan Dan Hasil Tanaman Talas (Colocasia Esculenta (L.) Schott Var. Antiquorum) Yang Ditanam Di Lahan Kering Pada Musim Kemarau

Kelompok tanaman dari umbi-umbian seperti tanaman talas memiliki potensi besar untuk dikembangkan karena dapat dimanfaatkan sebagai sumber bahan pangan alternatif yang sehat dan aman. Akan tetapi produksi umbi talas pada lahan kering masih rendah. Oleh karena itu, diperlukan upaya untuk meningkatkan produksi umbi talas pada lahan kering dengan aplikasi bahan organik. Tujuan penelitian adalah untuk mempelajari pengaruh tingkat pemupukan kompos UB pada pertumbuhan dan hasil tanaman talas dilahan kering dan menentukan tingkat pemupukan kompos UB yang optimum pada tanaman talas. Penelitian dilaksanakan dari bulan Mei – November 2014 di dusun Jetak Lor, desa Mulyoagung, Dau, Malang. Bahan yang digunakan ialah bibit tanaman talas varietas Antiquorum dan kompos UB. Penelitian menggunakan rancangan acak kelompok yang menempatkan dosis kompos UB sebagai perlakuan, terdiri dari 6 taraf yaitu: 0% (0 ton ha-1), 25% (1,51 ton ha-1), 50% (3,02 ton ha-1), 75% (4,53 ton ha-1), 100% (6,05 ton ha-1) dan 125% (7,56 ton ha-1). Hasil penelitian menunjukkan bahwa hasil panen per hektar yang lebih tinggi didapatkan pada aplikasi kompos UB dengan dosis 125%, yaitu sebesar 12,77 ton ha-1

Error Estimates on Parton Density Distributions

Error estimates on parton density distributions are presently based on the traditional method of least squares minimisation and linear error propagation in global QCD fits. We review the underlying assumptions and the various mathematical representations of the method and address some technical issues encountered in such a global analysis. Parton distribution sets which contain error information are described.Comment: Latex, 12 pages, 5 figures. Needs iopart.cls and iopart12.clo. Presented at New Trends in HERA Physics 2001, Ringberg Castle, Tegernsee, Germany, June 17-22, 200