High-field recovery of the undistorted triangular lattice in the frustrated metamagnet CuFeO2

Pulsed field magnetization experiments extend the typical metamagnetic staircase of CuFeO2 up to 58 T to reveal an additional first order phase transition at high field for both the parallel and perpendicular field configuration. Virtually complete isotropic behavior is retrieved only above this transition, indicating the high-field recovery of the undistorted triangular lattice. A consistent phenomenological rationalization for the field dependence and metamagnetism crossover of the system is provided, demonstrating the importance of both spin-phonon coupling and a small field-dependent easy-axis anisotropy in accurately describing the magnetization process of CuFeO2.Comment: 4 pages, 4 figure

Kajian Volume Serta Kinerja Lalu Lintas Jl.mt.haryono-jembatan Soekarno Hatta–jl.m.panjaitan–jl.bogor Atas–jl.veteran Dan Jl.gajayana

Dengan memperhatikan kinerja jaringan jalan satu arah (Jl.MT.Haryono - Jembatan Soekarno Hatta - Jl.M.Panjaitan - Jl.Bogor Atas - Jl.Veteran dan Jl.Gajayana) di kota Malang yang semakin ramai saat akhir pekan, maka diperlukannya upaya untuk menganalisis dan mencari solusi yang diperlukan agar dampak yang terjadi dapat diminimalisir. Skripsi ini bertujuan untuk mengetahui kinerja segmen jalan dan simpang untuk kondisi eksisting, kemudian menentukan manajemen lalu lintas yang sesuai apabila terdapat permasalahan, sehingga diharapkan dapat memberikan alternatif solusi dari permasalahan yang terjadi. Kajian yang dilakukan berupa analisa kinerja ruas, simpang dan jalinan serta menentukan manajemen lalu lintas yang sesuai. Data penelitian didapat dengan melakukan survei traffic counting pada hari Jumat dan Senin pukul 06.00-08.00 dan 15.00-17.00 serta pada lokasi jaringan jalan satu arah (Jl.MT.Haryono - Jembatan Soekarno Hatta - Jl.M.Panjaitan - Jl.Bogor Atas - Jl.Veteran dan Jl.Gajayana). Analisis kinerja simpang dan ruas mengacu pada MKJI 1997, sedangkan manajemen lalu lintas mengacu referensi terkait yaitu mengenai optimasi waktu siklus dan geometri. Sehingga diperoleh tingkat pelayanan masing-masing jaringan jalan di sekitar kawasan tersebut. Hasil yang diperoleh yaitu kondisi segmen jalan Bogor Atas kondisi eksisting pada tahun 2014 didapatkan bahwa rata-rata derajat kejenuhan (DS) sebesar 0.25, segmen jalan M.Panjaitan derajat kejenuhan (DS) sebesar 0.711, segmen jalan MT.Haryono derajat kejenuhan (DS) sebesar 0.752, segmen jalan Soekarno Hatta derajat kejenuhan (DS) sebesar 0.743, segmen jalan Gajayana derajat kejenuhan (DS) sebesar 0.736 dan segmen jalan Veteran derajat kejenuhan (DS) sebesar 0.595. Kondisi simpang 4 Bogor-Veteran didapatkan bahwa rata-rata tundaan sebesar 79.04 detik , untuk simpang 3 MT Haryono-Soehat tundaan sebesar 10.17 detik, untuk simpang 3 Gajayana-MT.Haryono tundaan sebesar 289.3 detik, untuk simpang 4 Soehat-Bunga Coklat tundaan sebesar 508.2 detik dan pada ruas simpang 4 Veteran-sumbersari tundaan sebesar 403.9 detik. Dengan memperhatikan kondisi seperti itu maka perlu adanya solusi perbaikan beberapa simpang pada jaringan jalan, yaitu pada simpang 4 Bogor-Veteran dipilih manajemen lalu lintas berupa Perubahan geometri serta optimasi waktu siklus, sedangkan pada simpang 3 Veteran -Sumbersari dilakukan Perubahan fase dari 3 fase menjadi 2 fase. Pada simpang 3 Gajayana-MT.Haryono cukup dilakukan Perubahan waktu siklus, namun apabila membutuhkan perbaikan untuk efek yang lebih baik serta bersifat jangka panjang, Perubahan geometri dapat menjadi pilihan dengan melakukan pembebasan lahan. Hal yang sama juga terjadi pada simpang 4 Soekarno Hatta-Bunga Coklat yang mana dilakukan Perubahan pengaturan sinyal dari 3 fase menjadi 2 fase, namun apabila membutuhkan perbaikan untuk efek yang lebih baik maka Perubahan geometri dapat menjadi pilihan dengan melakukan pembebasan lahan. Sedangkan pada ruas tidak memerlukan perbaikan karena diketahui tingkat pelayanan terburuk adalah C

Approximate Ginzburg-Landau solution for the regular flux-line lattice. Circular cell method

A variational model is proposed to describe the magnetic properties of type-II superconductors in the entire field range between $H_{c1}$ and $H_{c2}$ for any values of the Ginzburg-Landau parameter $\kappa>1/\sqrt{2}$. The hexagonal unit cell of the triangular flux-line lattice is replaced by a circle of the same area, and the periodic solutions to the Ginzburg-Landau equations within this cell are approximated by rotationally symmetric solutions. The Ginzburg-Landau equations are solved by a trial function for the order parameter. The calculated spatial distributions of the order parameter and the magnetic field are compared with the corresponding distributions obtained by numerical solution of the Ginzburg-Landau equations. The comparison reveals good agreement with an accuracy of a few percent for all $\kappa$ values exceeding $\kappa \approx 1$. The model can be extended to anisotropic superconductors when the vortices are directed along one of the principal axes. The reversible magnetization curve is calculated and an analytical formula for the magnetization is proposed. At low fields, the theory reduces to the London approach at $\kappa \gg 1$, provided that the exact value of $H_{c1}$ is used. At high fields, our model reproduces the main features of the well-known Abrikosov theory. The magnetic field dependences of the reversible magnetization found numerically and by our variational method practically coincide. The model also refines the limits of some approximations which have been widely used. The calculated magnetization curves are in a good agreement with experimental data on high-T$_c$ superconductors.Comment: 8 pages, RevTex, 6 figures, submitted to Phys. Rev.

Microwave Electrodynamics of Electron-Doped Cuprate Superconductors

We report microwave cavity perturbation measurements of the temperature dependence of the penetration depth, lambda(T), and conductivity, sigma(T) of Pr_{2-x}Ce_{x}CuO_{4-delta} (PCCO) crystals, as well as parallel-plate resonator measurements of lambda(T) in PCCO thin films. Penetration depth measurements are also presented for a Nd_{2-x}Ce_{x}CuO_{4-delta} (NCCO) crystal. We find that delta-lambda(T) has a power-law behavior for T<T_c/3, and conclude that the electron-doped cuprate superconductors have nodes in the superconducting gap. Furthermore, using the surface impedance, we have derived the real part of the conductivity, sigma_1(T), below T_c and found a behavior similar to that observed in hole-doped cuprates.Comment: 4 pages, 4 figures, 1 table. Submitted to Physical Review Letters revised version: new figures, sample characteristics added to table, general clarification give

The effect of sr-cofe2o4 nanoparticles with different particles sized as additives in cip-based magnetorheological fluid

This study investigated the effect of adding strontium (Sr)-doped cobalt ferrite (CoFe2O4) nanoparticles in carbonyl iron particle (CIP)-based magnetorheological fluids (MRFs). Sr-CoFe2O4 nanoparticles were fabricated at different particle sizes using co-precipitation at calcination temperatures of 300 and 400◦C. Field emission scanning electron microscopy (FESEM) was used to evaluate the morphology of the Sr-CoFe2O4 nanoparticles, which were found to be spherical. The average grain sizes were 71–91 nm and 118–157 nm for nanoparticles that had been calcinated at 300 and 400◦C, respectively. As such, higher calcination temperatures were found to produce larger-sized Sr-CoFe2O4 nanoparticles. To investigate the rheological effects that Sr-CoFe2O4 nanoparticles have on CIP-based MRF, three MRF samples were prepared: (1) CIP-based MRF without nanoparticle additives (CIP-based MRF), (2) CIP-based MRF with Sr-CoFe2O4 nanoparticles calcinated at 300◦C (MRF CIP+Sr-CoFe2O4-T300), and (3) CIP-based MRF with Sr-CoFe2O4 nanoparticles calcinated at 400◦C (MRF CIP+Sr-CoFe2O4-T400). The rheological properties of these MRF samples were then observed at room temperature using a rheometer with a parallel plate at a gap of 1 mm. Dispersion stability tests were also performed to determine the sedimentation ratio of the three CIP-based MRF samples

Collective orbital excitations in orbitally ordered YVO3 and HoVO3

We study orbital excitations in the optical absorption spectra of YVO3 and HoVO3. We focus on an orbital absorption band observed at 0.4 eV for polarization E parallel c. This feature is only observed in the intermediate, monoclinic phase. By comparison with the local crystal-field excitations in VOCl and with recent theoretical predictions for the crystal-field levels we show that this absorption band cannot be interpreted in terms of a local crystal-field excitation. We discuss a microscopic model which attributes this absorption band to the exchange of two orbitals on adjacent sites, i.e., to the direct excitation of two orbitons. This model is strongly supported by the observed dependence on polarization and temperature. Moreover, the calculated spectral weight is in good agreement with the experimental result.Comment: 12 pages, 9 figure

Electron Dynamics in Nd1.85_{1.85}Ce.15_{.15}CuO4+δ_{4+\delta}: Evidence for the Pseudogap State and Unconventional c-axis Response

Infrared reflectance measurements were made with light polarized along the a- and c-axis of both superconducting and antiferromagnetic phases of electron doped Nd$_{1.85}$Ce$_{.15}$CuO$_{4+\delta}$. The results are compared to characteristic features of the electromagnetic response in hole doped cuprates. Within the CuO$_2$ planes the frequency dependent scattering rate, 1/$\tau(\omega)$, is depressed below $\sim$ 650 cm$^{-1}$; this behavior is a hallmark of the pseudogap state. While in several hole doped compounds the energy scales associated with the pseudogap and superconducting states are quite close, we are able to show that in Nd$_{1.85}$Ce$_{.15}$CuO$_{4+\delta}$ the two scales differ by more than one order of magnitude. Another feature of the in-plane charge response is a peak in the real part of the conductivity, $\sigma_1(\omega)$, at 50-110 cm$^{-1}$ which is in sharp contrast with the Drude-like response where $\sigma_1(\omega)$ is centered at $\omega=0$. This latter effect is similar to what is found in disordered hole doped cuprates and is discussed in the context of carrier localization. Examination of the c-axis conductivity gives evidence for an anomalously broad frequency range from which the interlayer superfluid is accumulated. Compelling evidence for the pseudogap state as well as other characteristics of the charge dynamics in Nd$_{1.85}$Ce$_{.15}$CuO$_{4+\delta}$ signal global similarities of the cuprate phase diagram with respect to electron and hole doping.Comment: Submitted to PR

Driving Innovation through Big Open Linked Data (BOLD): Exploring Antecedents using Interpretive Structural Modelling

YesInnovation is vital to find new solutions to problems, increase quality, and improve profitability. Big open linked data (BOLD) is a fledgling and rapidly evolving field that creates new opportunities for innovation. However, none of the existing literature has yet considered the interrelationships between antecedents of innovation through BOLD. This research contributes to knowledge building through utilising interpretive structural modelling to organise nineteen factors linked to innovation using BOLD identified by experts in the field. The findings show that almost all the variables fall within the linkage cluster, thus having high driving and dependence powers, demonstrating the volatility of the process. It was also found that technical infrastructure, data quality, and external pressure form the fundamental foundations for innovation through BOLD. Deriving a framework to encourage and manage innovation through BOLD offers important theoretical and practical contributions

Health equity issues at the local level: Socio-geography, access, and health outcomes in the service area of the Hôpital Albert Schweitzer-Haiti

<p>Abstract</p> <p>Background</p> <p>Although health equity issues at regional, national and international levels are receiving increasing attention, health equity issues at the local level have been virtually overlooked. Here, we describe here a comprehensive equity assessment carried out by the Hôpital Albert Schweitzer-Haiti (HAS) in 2003. HAS has been operating health and development programs in the Artibonite Valley of Haiti for 50 years.</p> <p>Methods</p> <p>We reviewed all available information arising from a comprehensive evaluation of the programs of HAS carried out in 1999 and 2000. As part of this evaluation, two demographic and health surveys were carried out. We carried out exit interviews with clients receiving primary health care, observations within health facilities, interviews with households related to quality of care, and focus group discussions with community-based health workers. A special study was carried out in 2003 to assess factors determining the use of prenatal care services. Finally, selected findings were obtained from the HAS information system.</p> <p>Results</p> <p>We found markedly reduced access to health services in the peripheral mountainous areas compared to the central plains. The quality of services was more deficient and the coverage of key services was lower in the mountains. Finally, health status, as measured by under-five mortality rates and levels of childhood malnutrition, was also worse in the mountains.</p> <p>Conclusion</p> <p>These findings indicate that local health programs need to give attention to monitoring the health status as well as the quality and coverage of basic services among marginalized groups within the program service area. Health inequities will not be overcome until such monitoring occurs and leaders of health programs ensure that inequities identified are addressed in the local programming of activities. It is quite likely that, within relatively small geographic areas in resource-poor settings around the world, similar, if not even greater, levels of health inequities exist. These inequities need to be measured and addressed in order for health programs to achieve equity and maximum improvement in health status within the population.</p