Electron-ion and ion-ion potentials for modeling warm-dense-matter: applications to laser-heated or shock-compressed Al and Si

The pair-interactions U_{ij}(r) determine the thermodynamics and linear transport properties of matter via the pair-distribution functions (PDFs), i.e., g_{ij}(r). Great simplicity is achieved if U_{ij}(r) could be directly used to predict material properties via classical simulations, avoiding many-body wavefunctions. Warm dense matter (WDM) is encountered in quasi-equilibria where the electron temperature $T_e$ differs from the ion temperature T_i, as in laser-heated or in shock-compressed matter. The electron PDFs g_{ee}(r) as perturbed by the ions are used to evaluate fully non-local exchange-correlation corrections to the free energy, using Hydrogen as an example. Electron-ion potentials for ions with a bound core are discussed with Al and Si as examples, for WDM with T_e \ne T_i, and valid for times shorter than the electron-ion relaxation time. In some cases the potentials develop attractive regions, and then become repulsive and `Yukawa-like' for higher $T_e$. These results clarify the origin of initial phonon-hardening and rapid release. Pair-potentials for shock-heated WDM show that phonon hardening would not occur in most such systems. Defining meaningful quasi-equilibrium static transport coefficients consistent with the dynamic values is addressed. There seems to be no meaningful `static conductivity' obtainable by extrapolating experimental or theoretical \sigma(\omega, T_i, T_e) to \omega \to 0, unless T_i \to T_e as well. Illustrative calculations of quasi-static resistivities R(T_i,T_e) of laser-heated as well as shock-heated Aluminum and Silicon are presented using our pseudopotentials, pair-potentials and classical integral equations. The quasi-static resistivities display clear differences in their temperature evolutions, but are not the strict \omega \to 0 limits of the dynamic values.Comment: 12 pages, 6 figues, Latex file

The Equation of State and the Hugoniot of Laser Shock-Compressed Deuterium

The equation of state and the shock Hugoniot of deuterium are calculated using a first-principles approach, for the conditions of the recent shock experiments. We use density functional theory within a classical mapping of the quantum fluids [ Phys. Rev. Letters, {\bf 84}, 959 (2000) ]. The calculated Hugoniot is close to the Path-Integral Monte Carlo (PIMC) result. We also consider the {\it quasi-equilibrium} two-temperature case where the Deuterons are hotter than the electrons; the resulting quasi-equilibrium Hugoniot mimics the laser-shock data. The increased compressibility arises from hot $D^+-e$ pairs occuring close to the zero of the electron chemical potential.Comment: Four pages; One Revtex manuscript, two postscipt figures; submitted to PR

Surface-directed spinodal decomposition in the pseudobinary alloy (HfO_2)_x(SiO_2)_{1-x}

Hf silicate films (HfO_2)_{0.25}(SiO_2)_{0.75} with thicknesses in the range 4-20 nm were grown on silicon substrate by atomic layer deposition at 350 deg.C.The Hf distributions in as-grown and 800 deg.C annealed films were investigated by high resolution transmission electron microscopy (HRTEM), angle-resolved x-ray photoelectron spectroscopy (ARXPS) and medium energy ion scattering (MEIS). HRTEM images show a layered structure in films thinner than 8 nm. The ARXPS data also reveal a non-uniform distribution of Hf throughout the film depth. Diffusion of SiO_2 to the film surface after a longer time anneal was observed by MEIS. All these observations provide evidence for surface-directed spinodal decomposition in the pseudobinary (HfO_2)_x(SiO_2)_{1-x} alloy system.Comment: 1o figures, one tabl

Perancangan Mesin Pemotong Kawat Bendrat Di PT. Surabaya Wire

Persaingan ketat di dunia industri seringkali menuntut pengusaha untuk menggunakan proses otomasi agar dapat meningkatkan kinerja mereka. Proses penimbangan dan pemotongan yang ada pada PT. Surabaya Wire masih manual dan membutuhkan waktu yang lama, sehingga dibutuhkan sebuah alat yang dapat memisahkan 1 kg kawat bendrat dan memotongnya secara otomatis. Proses ini dibagi menjadi dua bagian besar yaitu bagian pemisahan 1 kg kawat bendrat dan bagian pemotongan. Konsep dasar untuk memisahkan 1 kg kawat bendrat adalah dengan menggunakan panjangnya sebagai acuan. Ketika panjang kawat bendrat sudah sama dengan 1 kg, maka gulungan kawat akan dipisahkan dan dilanjutkan ke proses pemotongan. Bagian pemotongan menggunakan konsep sebuah tang potong namun lengan pemotong dimodifikasi agar dapat dilewati oleh gulungan kawat yang jatuh dari mesin coiler dan akhirnya dapat dipotong. Simulasi akan dilakukan terlebih dahulu sebelum proses fabrikasi.. Simulasi hanya dilakukan pada bagian pengambilan 1 kg. Simulasi yang dilakukan gagal karena pengambilan kawat tersebut ketika ditimbang terbaca 1.57 kg. Sehingga dibutuhkan penyesuaian lebih lanjut agar rancangan dapat berhasil

Faktor-faktor yang Berhubungan dengan Rendahnya Kepemilikan Jamban Keluarga dan Personal Hygiene dengan Kejadian Diare di Desa Sei Musam Kendit Kecamatan Bahorok Kabupatenlangkat Tahun 2014

One of health efforts in society is basic sanitation. One of basic sanitation facility in society is latrine. Latrine is useful for the dispose of human feces so the bacteria in the feces did not pollutes the environment and then environment is clean with good esthetic. This aim of this research is to study the factors realted to the few of ownership of household\u27s latrine and personal hygiene with diarrhea incidence in Desa Sei Musam Kendit, sub district of Bahorok, regency of Langkat. This research is analytic study with cross sectional study using the primary data was collected from the responden of household with questionnaire instrument and the secondary data from Puskesmas Bukit Lawang. The data was analyzed by analytic and statitical test with chi square test with 95% CI. The result of statistic analysis indicates that there is a significant correlation to the education and ownership of household\u27s latrine (p=0.049),the income ownership of household\u27s latrine(0,001),the knowledge on ownership of household\u27s latrine(p=0,002),the ownership of latrine with diarrhea incidence(p=0,002)and personal hygiene with diarrhea incidence (p=0,007).and there is a significant correlation between the attitudes and ownership of household\u27s latrine(p=0,095) and between the association ownership of household\u27s latrine(p=939). It is suggested to the people who lives in Desa Sei Musam Kendit to pay attention to personal hygiene and use the latrine that fulfill the health requirement to avoid the transmission of diarrhea and the health staff must provide the society with activity about the importance of personal hygiene, the ownership of household\u27s latrine and the importance of environment sanitation

Electronic States of Magnetic Quantum Dots

We study quantum states of electrons in magnetically doped quantum dots as a function of exchange coupling between electron and impurity spins, the strength of Coulomb interaction, confining potential, and the number of electrons. The magnetic phase diagram of quantum dots, doped with a large number of magnetic Mn impurities, can be described by the energy gap in the spectrum of electrons and the mean field electron-Mn exchange coupling. A competition between these two parameters leads to a transition between spin-unpolarized and spin-polarized states, in the absence of applied magnetic field. Tuning the energy gap by electrostatic control of nonparabolicity of the confining potential can enable control of magnetization even at the fixed number of electrons. We illustrate our findings by directly comparing Mn-doped quantum dots with parabolic and Gaussian confining potential.Comment: 5 pages, 5 figures, Part of Focus on Spintronics in Reduced Dimension

The rural bite in population pyramids: what are the implications for responsiveness of health systems in middle income countries?

BackgroundHealth services can only be responsive if they are designed to service the needs of the population at hand. In many low and middle income countries, the rate of urbanisation can leave the profile of the rural population quite different from the urban population. As a consequence, the kinds of services required for an urban population may be quite different from that required for a rural population. This is examined using data from the South East Asia Community Observatory in rural Malaysia and contrasting it with the national Malaysia population profile.MethodsCensus data were collected from 10,373 household and the sex and age of household members was recorded. Approximate Malaysian national age and sex profiles were downloaded from the US Census Bureau. The population pyramids, and the dependency and support ratios for the whole population and the SEACO sub-district population are compared.ResultsBased on the population profiles and the dependency ratios, the rural sub-district shows need for health services in the under 14 age group similar to that required nationally. In the older age group, however, the rural sub-district shows twice the need for services as the national data indicate.ConclusionThe health services needs of an older population will tend towards chronic conditions, rather than the typically acute conditions of childhood. The relatively greater number of older people in the rural population suggest a very different health services mix need. Community based population monitoring provides critical information to inform health systems