Validating Continuum Lowering Models via Multi-Wavelength Measurements of Integrated X-ray Emission

X-ray emission spectroscopy is a well-established technique used to study continuum lowering in dense plasmas. It relies on accurate atomic physics models to robustly reproduce high-resolution emission spectra, and depends on our ability to identify spectroscopic signatures such as emission lines or ionization edges of individual charge states within the plasma. Here we describe a method that forgoes these requirements, enabling the validation of different continuum lowering models based solely on the total intensity of plasma emission in systems driven by narrow-bandwidth x-ray pulses across a range of wavelengths. The method is tested on published Al spectroscopy data and applied to the new case of solid-density partially-ionized Fe plasmas, where extracting ionization edges directly is precluded by the significant overlap of emission from a wide range of charge states

Aplikasi Model Altman Z”-score Pada Perusahaan-Perusahaan Agrikultur Di Bursa Efek Indonesia (Periode 2010-2017)

Penelitian ini bertujuan untuk mengaplikasikan salah satu model prediksi kebangkrutan bernama Altman Z-Score, khususnya model yang dapat digunakan untuk mengukur financial distress dari Perusahaan-Perusahaan non-manufaktur (Z”-Score), pada Perusahaan-Perusahaan yang masuk di dalam Indeks Saham Agrikultur di Bursa Efek Indonesia. Sampel yang digunakan di dalam penelitian ini berjumlah delapan Perusahaan dengan menggunakan purposive sampling method. Laporan keuangan tahunan Perusahaan dari tahun 2010 sampai 2017 merupakan jenis data sekunder yang digunakan di penelitian ini.Analisa deskriptif kuantitatif digunakan untuk mendiskusikan hasil perhitungan Z”-Score masing-masing Perusahaan sampel di setiap tahun observasinya. Diharapkan bahwa hasil penelitian ini dapat memberikan gambaran dan solusi bagi pihak manajemen Perusahaan untuk memperbaiki kondisi keuangan di Perusahaan yang dikelolanya. Di sisi lain, hasil penelitian ini juga diharapkan dapat bermanfaat bagi para investor sebagai salah satu alat pengambilan keputusan untuk menempatkan dana investasinya pada Perusahaan yang tepat

Simulations of Collisional Effects in an Inner-Shell Solid-Density Mg X-Ray Laser

Inner-shell K$\alpha$ x-ray lasers have been created by pumping gaseous, solid, and liquid targets with the intense x-ray output of free-electron-lasers (FELs). For gaseous targets lasing relies on the creation of K-shell core-holes on a time-scale short compared with filling via Auger decay. In the case of solid and liquid density systems, collisional effects will also be important, affecting not only populations, but also line-widths, both of which impact the degree of overall gain, and its duration. However, to date such collisional effects have not been extensively studied. We present here initial simulations using the CCFLY code of inner-shell lasing in solid density Mg, where we self-consistently treat the effects of the incoming FEL radiation and the atomic kinetics of the Mg system, including radiative, Auger, and collisional effects. We find that the combination of collisional population of the lower states of the lasing transitions and broadening of the lines precludes lasing on all but the K$\alpha$ of the initially cold system. Even assuming instantaneous turning on of the FEL pump, we find the duration of the gain in the solid system to be sub-femtosecond.Comment: This paper has been submitted to Philosophical Transactions

XUV Opacity of Aluminum between the Cold-Solid to Warm-Plasma Transition

We present calculations of the free-free XUV opacity of warm, solid-density aluminum at photon energies between the plasma frequency at 15 eV and the L-edge at 73 eV, using both density functional theory combined with molecular dynamics and a semi-analytical model in the RPA framework with the inclusion of local field corrections. As the temperature is increased from room temperature to 10 eV, with the ion and electron temperatures equal, we calculate an increase in the opacity in the range over which the degree of ionization is constant. The effect is less pronounced if only the electron temperature is allowed to increase. The physical significance of these increases is discussed in terms of intense XUV-laser matter interactions on both femtosecond and picosecond time-scales.Comment: 4 pages, 3 figure

Correlation energy of the paramagnetic electron gas at the thermodynamic limit

The variational and diffusion quantum Monte Carlo methods are used to calculate the correlation energy of the paramagnetic three-dimensional homogeneous electron gas at intermediate to high density. Ground state energies in finite cells are determined using Slater-Jastrow-backflow trial wave functions, and finite-size errors are removed using twist-averaged boundary conditions and extrapolation of the energy per particle to the thermodynamic limit of infinite system size. Our correlation energies in the thermodynamic limit are lower (i.e., more negative, and therefore more accurate according to the variational principle) than previous results, and can be used for the parameterization of density functionals to be applied to high-density systems

Reciprocity of Networks with Degree Correlations and Arbitrary Degree Sequences

Although most of the real networks contain a mixture of directed and bidirectional (reciprocal) connections, the reciprocity $r$ has received little attention as a subject of theoretical understanding. We study the expected reciprocity of networks with an arbitrary degree sequence and a broad class of degree correlations by means of statistical ensemble approach. We demonstrate that degree correlations are crucial to understand the reciprocity in real networks and a hierarchy of correlation contributions to $r$ is revealed. Numerical experiments using novel network randomization methods show very good agreement to our analytical estimations.Comment: 8 pages, 3 figures, added a new table and a new figure, accepted for publication in Phys.Rev.

Model Kebijakan Modal Kerja Pada UMKM Di Desa Wisata “Cengek” Tingkir Lor, Salatiga

Penelitian ini bertujuan untuk mengetahui model kebijakan modal kerja yang digunakan oleh Usaha Mikro, Kecil dan Menengah (UMKM) di Desa Wisata "Cengek" Tingkir Lor, Salatiga.Metode penelitian dalam penelitian ini menggunakan analisis deskriptif kuantitatif dan teknik pengambilan sampel dengan observasi dan wawancara. Metode pemilihan sampel yang digunakan adalah purposive sampling dengan sampel sebanyak 20 UMKM. Hasil penelitian menunjukkan bahwa 70% pengusaha UKM di Desa Wisata "Cengek" Tingkir Lor, Salatiga menggunakan kebijakan modal kerja yang moderat, 15% menggunakan kebijakan modal kerja konservatif dan sisanya 15% menggunakan kebijakan agresif. Rekomendasi dari hasil penelitian ini adalah (1) pengusaha UKM mulai membawa investor sebagai pemodal dengan perhitungan bisnis yang disepakati (2) pengusaha UKM yang menggunakan kebijakan modal kerja konservatif harus berani menggunakan dana eksterna