Structural Modification and Metamagnetic Anomaly in the Ordered State of CeOs2Al10

A caged compound CeOs2Al10, crystallizing in the orthorhombic YbFe2Al10-type structure, undergoes a mysterious phase transition at T_0=29 K. We report the results of electron diffraction, magnetization, and magnetoresistance for single crystals. Superlattice reflections characterized by a wave vector q = (0, -2/3, 2/3) observed at 15 K indicate a structural modification in the ordered state. Activation-type behavior of the electrical resistivity along the three principal axes below 50 K suggests gap opening in the conduction band. The magnetic susceptibility \chi = M/B is highly anisotropic, \chi_a>\chi_c>\chi_b, all of which sharply decrease on cooling below T_0. Furthermore, a metamagnetic anomaly in the magnetization and a step in the magnetoresistance occur at B=6-8 T only when the magnetic field is applied parallel to the orthorhombic c axis. However, T_0 hardly changes under magnetic fields up to 14 T, irrespective of the field direction. By using these data, we present a B-T phase diagram and discuss several scenarios for the mysterious transition.Comment: 6 pages, 7 figures, accepted for publication in Phys. Rev.

Assessing the tsunami mitigation effectiveness of the planned Banda Aceh Outer Ring Road (BORR), Indonesia

This research aimed to assess the tsunami flow velocity and height reduction produced by a planned elevated road parallel to the coast of Banda Aceh, called the Banda Aceh Outer Ring Road (BORR). The road will transect several lagoons, settlements, and bare land around the coast of Banda Aceh. Beside its main function to reduce traffic congestion in the city, the BORR is also proposed to reduce the impacts of future tsunamis. The Cornell Multi-grid Coupled Tsunami Model (COMCOT) was used to simulate eight scenarios of the tsunami. One of them was based on the 2004 Indian Ocean tsunami. Two magnitudes of earthquake were used, that is, 8.5 and 9.15&thinsp;Mw. Both the earthquakes were generated from the same source location as in the 2004 case, around the Andaman Sea. Land use data of the innermost layer of the simulation area were adopted based on the 2004 condition and the land use planning of the city for 2029. The results of this study reveal that the tsunami inundation area can be reduced by about 9&thinsp;% by using the elevated road for the earthquake of magnitude 9.15&thinsp;Mw and about 22&thinsp;% for the earthquake of magnitude 8.5&thinsp;Mw. Combined with the land use planning 2029, the elevated road could reduce the maximum flow velocities behind the road by about 72&thinsp;%. Notably, the proposed land use for 2029 will not be sufficient to deliver any effects on the tsunami mitigation without the elevated road structures. We recommend the city to construct the elevated road as this could be part of the co-benefit structures for tsunami mitigation. The proposed BORR appears to deliver a significant reduction of impacts of the smaller intensity tsunamis compared to the 2004 Indian Ocean tsunami.</p

CeRh₂Al₁₀ - The first rhodium aluminide with a new structure type in the 1:2:10 stoichiometry family

A new member of the RET2Al10 family was synthesized and its crystal structure was determined from single crystal X-ray diffraction. The first aluminide with rhodium adopts a new structure type of 1:2:10 stoichiometry. CeRh2Al10 crystallizes in the tetragonal space group I4(1)/amd with cell parameters a = 8.9284(11) angstrom and c = 21.769(3) angstrom and is a substitution variant of CePd3Al9 compound. The mutual arrangement of Rh and Al neighbors within the 20-vertex Ce polyhedron differs in comparison with that of the CeRu2Al10 structure. This leads to the different packing of Ce polyhedra in the unit cell. In CeRh2Al10, zig-zag chains of the shortest Ce-Ce contacts extend in the two mutually perpendicular directions - along the a-axis and along the b-axis. In contrast, in CeRu2Al10, zig-zag chains of the shortest Ce-Ce contacts run in one direction - along the c-axis. We illustrate using key physical properties how the variation in crystal structure produces physical properties in CeRh2Al10 that differ strikingly from the situation in CeRu2Al10. (C) 2017 Elsevier B.V. All rights reserved

New ternary aluminides RERh₄Al₁₅ (RE = La, Ce, Pr, Sm, Gd)

The aluminum-rich intermetallic rare earth compounds RERh4Al15 (RE = La, Ce Pr, Sm, Gd) were synthesized by arc melting of the elements under an argon atmosphere. The samples were characterized by powder X-ray diffraction which revealed a straight-forward agreement of the synthesized materials with tetragonal space group P4(2)/nmc, NdRh4Al15.37 structure type. The structures of CeRh4Al15 and PrRh4Al15 were refined from single-crystal X-ray diffraction data. CeRh4Al15 is a new correlated electron compound with Kondo interaction. There is no magnetic ordering above 0.05 K despite the localized Ce3+ magnetic moment behaviour near room temperature. The electronic specific heat, magnetic susceptibility and electrical resistivity indicate that the compound may be accidently poised near a magnetic quantum critical point. (C) 2019 Elsevier B.V. All rights reserved

Poor Sleep Quality Differences Among Adolescents with Smartphone Addiction Compared to Adolescents Without Smartphone Addiction

Introduction: An adolescent aggregate is an age group with a high rate of smartphone addiction. Poor sleep quality in adolescents is one of the negative effects resulting from smartphone addiction Objective: To analyse poor sleep quality differences among adolescents with smartphone addiction compared to those without Methods: Analytical observational design with a cross-sectional approach was used in this study, involving 165 secondary school students as the participants. Study variables include smartphone addiction and poor sleep quality. The instruments used for data collection are the Pittsburgh Sleep Quality Index (PSQI) questionnaire and the Smartphone Addiction Scale: Short Version (SAS-SV). The statistical analysis performed was the Mann Whitney test. Results: The statistical test results obtained a p-value &lt; alpha (0,000 &lt; 0,05), which means at a 95% confidence level, there was a difference in the poor sleep quality score between adolescents with smartphone addiction compared to those without. Adolescents with smartphone addiction have higher poor sleep quality scores compared to adolescents without smartphone addiction. Conclusion: Adolescents should be able to limit the use of the smartphone according to their needs and minimise smartphone use before going to bed at night

PENGARUH MODEL PEMBELAJARAN INKUIRI TERBIMBING TERHADAP KETERAMPILAN BERPIKIR KREATIF DAN KETERAMPILAN PROSES SAINS PESERTA DIDIK KELAS X DI SMAN 1 RHEE

Penelitian bertujuan untuk mengetahui (1) Pengaruh model pembelajaran inkuiri terbimbing terhadap keterampilan berpikir kreatif peserta didik kelas X SMAN 1 Rhee; (2) Pengaruh model pembelajaran inkuiri terbimbing terhadap keterampilan proses sains peserta didik kelas X SMAN 1 Rhee; dan (3) Seberapa besar peningkatan keterampilan berpikir kreatif dan keterampilan proses sains setelah digunakan model inkuiri terbimbing. Populasi penelitian adalah peserta didik kelas X yang berjumlah 64 peserta didik dan ditetapkan sampel dilakukan dengan teknik sampling jenuh. Metode yang digunakan adalah quasi eksperimen. Pengumpulan data dilakukan dengan teknik tes. Pengolahan data menggunakan teknik statistik sederhana dalam bentuk perhitungan uji z dan uji gain. Hasil analisis data menunjukkan keterampilan berpikir kreatif diperoleh zhitung sebesar 4,318. Jika dibandingkan dengan ztabel sebesar 1,690. Jadi terdapat pengaruh penerapan pembelajaran inkuiri terbimbing terhadap keterampilan berpikir kreatif . Hasil analisis data keterampilan proses sains diperoleh zhitung sebesar 5,181. Jika dibandingkan dengan ztabel sebesar 1,690 (zhitung 5,181 &gt; ztabel 1,690). Jadi terdapat pengaruh penerapan pembelajaran inkuiri terbimbing terhadap keterampilan proses sains. Perhitungan gain keterampilan berpikir kreatif kelas kontrol dan eksperimen masing-masing diperoleh gain 0,295 dan 0,598 dengan kriteria rendah dan sedang. Artinya&nbsp; keterampilan berpikir kreatif mengalami peningkatan dari katagori rendah ke sedang. Sementara hasil&nbsp; perhitungan gain keterampilan proses sains kelas kontrol dan &nbsp;&nbsp;eksperimen &nbsp;diperoleh gain&nbsp; 0,261 dan 0,509. Artinya&nbsp; keterampilan proses sains mengalami peningkatan dari rendah ke sedang sebesar 0,248

R 8-x Ru 3 In 7+x , R 3 Ru 1-x In 3 , R 39 Ru 12-x In 35 , and R 16 Ru 5 In 14 (R=La-Nd, Sm, Gd-Er, Lu) - New ternary indides with 2D intergrowth of CsCl- and AlB 2 -related slabs

International audienceTwelve rare-earth ruthenium indides were synthesized by a two-step reaction and their crystal structures were determined by single-crystal X-ray diffraction. R3Ru1-xIn3 (Pbam, oP28) and R16Ru5In14 (P2/m, mP35) crystallize with new structure types whereas R39Ru12-xIn35 (Pbam, oP172) and R8-xRu3In7+x (Pmma, oP36) present occupation variants of Nd39Ir10.98In36.02 and Y5Cu5Mg8 structures, respectively. The new indides are built of two different layers alternatively stacking along the shortest unit cell axis. The first layer is formed exclusively of rare-earth atoms while the second layer is built of ruthenium and indium thus displaying RIn and RRu fragments of CsCl type and RIn2 and RRu2 fragments of AlB2 type