Electron acceleration by cascading reconnection in the solar corona I Magnetic gradient and curvature effects

Aims: We investigate the electron acceleration in convective electric fields of cascading magnetic reconnection in a flaring solar corona and show the resulting hard X-ray (HXR) radiation spectra caused by Bremsstrahlung for the coronal source. Methods: We perform test particle calculation of electron motions in the framework of a guiding center approximation. The electromagnetic fields and their derivatives along electron trajectories are obtained by linearly interpolating the results of high-resolution adaptive mesh refinement (AMR) MHD simulations of cascading magnetic reconnection. Hard X-ray (HXR) spectra are calculated using an optically thin Bremsstrahlung model. Results: Magnetic gradients and curvatures in cascading reconnection current sheet accelerate electrons: trapped in magnetic islands, precipitating to the chromosphere and ejected into the interplanetary space. The final location of an electron is determined by its initial position, pitch angle and velocity. These initial conditions also influence electron acceleration efficiency. Most of electrons have enhanced perpendicular energy. Trapped electrons are considered to cause the observed bright spots along coronal mass ejection CME-trailing current sheets as well as the flare loop-top HXR emissions.Comment: submitted to A&

Coexistence of superconductivity and antiferromagnetism in self-doped bilayer t-t'-J model

A self-doped bilayer t-t'-J model of an electron- and a hole-doped planes is studied by the slave-boson mean-field theory. A hopping integral between the differently doped planes, which are generated by a site potential, are renormalized by the electron-electron correlation. We find coexistent phases of antiferromagnetic (AFM) and superconducting orders, although the magnitudes of order parameters become more dissimilar in the bilayer away from half-filling. Fermi surfaces (FS's) with the AFM order show two pockets around the nodal and the anti-nodal regions. These results look like a composite of electron- and hole-doped FS's. In the nodal direction, the FS splitting is absent even in the bilayer system, since one band is flat due to the AFM order.Comment: 6 pages, 4 figure

Positive exchange bias in ferromagnetic La0.67Sr0.33MnO3 / SrRuO3 bilayers

Epitaxial La0.67Sr0.33MnO3 (LSMO)/ SrRuO3 (SRO) ferromagnetic bilayers have been grown on (001) SrTiO3 (STO) substrates by pulsed laser deposition with atomic layer control. We observe a shift in the magnetic hysteresis loop of the LSMO layer in the same direction as the applied biasing field (positive exchange bias). The effect is not present above the Curie temperature of the SRO layer (), and its magnitude increases rapidly as the temperature is lowered below . The direction of the shift is consistent with an antiferromagnetic exchange coupling between the ferromagnetic LSMO layer and the ferromagnetic SRO layer. We propose that atomic layer charge transfer modifies the electronic state at the interface, resulting in the observed antiferromagnetic interfacial exchange coupling.Comment: accepted to Applied Physics Letter

A hybrid approach to fuzzy risk analysis in stock market

The analysis and prediction of stock market has always been well recognized as a difficult problem due to the level of uncertainty and the factors that affect the price. To tackle this challenge problem, this paper proposed a hybrid approach which mines the useful information utilizing grey system and fuzzy risk analysis in stock prices prediction. In this approach, we firstly provide a model which contains the fuzzy function, k-mean algorithm and grey system (shorted for FKG), then provide the model of fuzzy risk analysis (FRA). A practical example to describe the development of FKG and FRA in stock market is given, and the analytical results provide an evaluation of the method which shows promote results. © 2013 IEEE

Integrasi Perencanaan Produksi Aggregat Dan Perencanaan Kebutuhan Mesin Pada Proses Produksi Ubin Keramik

Usually aggregate production planning and machine requirement planning are conducted separately although there is a close relationship between the two in most production environment. Integration model includes both production and workforce planning decision along with production equipment procurement towards production cost. Research by Behnezhad and Khoshnevis8.2) has shown that mathematical programming model based on this integration could result in cost saving when compared to the use of aggregate production planning and machine requirement planning separately. The advantage of using integration model in tiles production is going to be analyzed in this paper. The integration model is built based on data that is obtained from a tile company and the solution of the model is obtained by using the Quant-system software. The result showed that integration model yield cost saving of Rp.179.453.030,- towards the aggregate production planning and Rp.470.062.980,- towards the machine requirement planning

Search for Zs1+Z^{+}_{s1} and Zs2+Z^{+}_{s2} strangeonium-like structures

Theoretically, it has been presumed from an effective Lagrangian calculation that there could exist two charged strangeonium-like molecular states $Z^{+}_{s1}$ and $Z^{+}_{s2}$, with $K\bar{K}^{*}$ and $K^{*}\bar{K}^{*}$ configurations respectively. In the framework of QCD sum rules, we predict that masses of $Z^{+}_{s1}$ ($K\bar{K}^{*}$) and $Z^{+}_{s2}$ ($K^{*}\bar{K}^{*}$) are $1.85\pm0.14 GeV$ and $2.02\pm0.15 GeV$ respectively, which are both above their respective two meson thresholds. We suggest to put in practice the search for these two charged strangeonium-like structures in future experiments.Comment: 7 pages, 4 eps figures; the version accepted for publication in PRD. arXiv admin note: text overlap with arXiv:1203.070

Desain Eksperimen Untuk Mengoptimalkan Proses Pengecoran Saluran Keluar Teko

The most frequently found defect in the casting process of making teapots out flue is that the outlet is too narrow or even blocked at the end of the casting process. There are many factors influence that defect. This defect condition can be represented as the thickness of the casting product. In this paper, the significant factors that influence the thickness of the out flue resulted from the casting process will be analyzed and further got their optimum conditions. Design experiments methods will be implemented here, especially the factorial design method to determine the significant factors along with their optimum conditions. Also, the response surface method will be applied to obtain the approximation model for the thickness of the out flue as a function of the factors found earlier so that the most optimal result can be obtained under a design optimization method. It is concluded from the experiments results and analysis that the significant factors for the thickness of out flue are pouring temperature, sprue radius and holding time. The optimum conditions of those factors are 475°C, 29.6 mm and 8 seconds respectively with 2.54 mm thickness

The new radiation-hard optical links for the ATLAS pixel detector

The ATLAS detector is currently being upgraded with a new layer of pixel based charged particle tracking and a new arrangement of the services for the pixel detector. These upgrades require the replacement of the opto-boards previously used by the pixel detector. In this report we give details on the design and production of the new opto-boards.Comment: Presentation at the DPF 2013 Meeting of the American Physical Society Division of Particles and Fields, Santa Cruz, California, August 13-17, 201

Crab culture potential in southwestern Bangladesh: alternative to shrimp culture for climate change adaption

Outbreaks of disease, price increases, international competition and impact of climate change has setback shrimp culture in the coastal region of Bangladesh. In this changing environment, crab has emerged as a potential exportable commodity in the country. Farmers are transferring to crab farming as it is less susceptible to disease, resistant to adverse environmental conditions and has a good market price. This paper highlights the application of remote sensing and GIS for crab culture potential. The paper discusses the imminent capabilities of satellite imaging technology and Multi criteria evaluation (MCE) module in GIS environment for development of sustainable crab aquaculture consisted physical, environmental and socioeconomic data to evaluate coastal land based criteria for mud carb farming based on water quality, water availability, salinity, risks of flooding, soil types, topography, land use/land cover; infrastructure, inputs, seed sources, market and support services. All the layers with associated attribute data were digitally encoded in a GIS database to create thematic layers. The database was verified to remove the inconsistency if any. The expert opinions were combined into the model by assigning weights of relative importance to evaluate crab farming and land suitability was categorized as very suitable, moderate suitable, marginal suitable and currently not suitable by implementing the logical criteria. MCE identified a range of suitable land parcels with unique characteristics. The resultant map reveals that a considerable amount of land (28.33%) fell under very suitable category which is situated in the northwest and southwestern part of the area. On the other hand, majority of the land parcel (62.22%) fell within the moderately suitable group that is scattered throughout the area and approximately 9.45% of land was only marginally suitable for crab culture. However, there is no land parcel designated as unsuitable in the present study for crab culture. The suitability output is replicable within the study area and transferable to other areas for other cultured specie