Spiciness

We define and present algorithms for spiciness, which is an oceanographic variable whose isopycnal variations reflect isopycnal water-mass contrasts in density units. Discussion of spiciness in the oceanographic literature has often concentrated on its supposed orthogonality to isopycnals on the salinity-temperature diagram and how this orthogonal nature means that spiciness is a “passive” thermodynamic variable. Here we show that this “orthogonal” property is devoid of physical meaning. Moreover, it is emphasized that the notion of “orthogonality” on the salinity-temperature diagram does not give rise to a passive thermodynamic variable. Rather, the passive nature of variations of any thermodynamic variable is gained by evaluating those variations along isopycnals so that, for example, the isopycnal variations of both Absolute Salinity and Conservative Temperature are passive. The advantage of using isopycnal variations of our definition of spiciness is that this measures the passive spatial variations of water-mass properties in density units. The spiciness variables presented here have been derived using the equation of state from the International Thermodynamic Equation of Seawater – 2010

Dimensional Stability of Acetylated Aspen Flakeboard

This study was conducted to determine if thickness swelling of flakeboards, which is much greater than that of plywood or solid wood, can be improved by chemical modification of the constituent wood flakes prior to board manufacture. The chemical treatment involved acetylation of oven-dry aspen ring flakes with a 50/50 mixture of acetic anhydride and xylene. Thickness swell of treated and control samples was measured by either immersion in water for periods of up to 10 days or exposure to 90% relative humidity for periods of up to 20 days. Treated samples exhibited one-sixth to one-seventh the thickness swelling of controls for the water-soak test. Similar trends were observed for humidity exposure

Multigrid reduction-in-time convergence for advection problems: A Fourier analysis perspective

A long-standing issue in the parallel-in-time community is the poor convergence of standard iterative parallel-in-time methods for hyperbolic partial differential equations (PDEs), and for advection-dominated PDEs more broadly. Here, a local Fourier analysis (LFA) convergence theory is derived for the two-level variant of the iterative parallel-in-time method of multigrid reduction-in-time (MGRIT). This closed-form theory allows for new insights into the poor convergence of MGRIT for advection-dominated PDEs when using the standard approach of rediscretizing the fine-grid problem on the coarse grid. Specifically, we show that this poor convergence arises, at least in part, from inadequate coarse-grid correction of certain smooth Fourier modes known as characteristic components, which was previously identified as causing poor convergence of classical spatial multigrid on steady-state advection-dominated PDEs. We apply this convergence theory to show that, for certain semi-Lagrangian discretizations of advection problems, MGRIT convergence using rediscretized coarse-grid operators cannot be robust with respect to CFL number or coarsening factor. A consequence of this analysis is that techniques developed for improving convergence in the spatial multigrid context can be re-purposed in the MGRIT context to develop more robust parallel-in-time solvers. This strategy has been used in recent work to great effect; here, we provide further theoretical evidence supporting the effectiveness of this approach

Anodic growth of nanoporous tin oxide layers in acidic electrolytes

The aim of this work was to synthesize SnO2 nanostructures with various morphologies by simple anodic oxidation (anodization) of metallic tin in acidic electrolytes. A series of Sn foil anodizations was performed in different electrolytes (oxalic acid, citric acid, tartaric acid) with various concentrations. It was confirmed that anodic oxidation of tin in the oxalic acid results in the formation of nanoporous oxide layers with completely open pores on the surface of the electrode. On the other hand, when citric acid or tartaric acid were used as an electrolyte, porous oxide with a compact layer on the surface was formed during electrolysis

Kemampuan Siswa Dalam Menyelesaikan Soal-soal Uraian Terstruktur Pokok Bahasan Teori Kinetik Gas

"> Penelitian ini bertujuan untuk mengetahui (1) kemampuan kognitif yang dilihat dari hasil belajar peserta didik yang kelas XI MAN Model Palangka Raya dalam mengerjakan soal-soal uraian terstruktur pada pokok bahasan Teori Kinetik Gas; dan (2) kesulitan peserta didik dalam mengerjakan soal-soal uraian terstruktur. Penelitian ini menggunakan metode penelitian kuantitatif dalam mengumpulkan datanya. Penelitian ini menggunakan instrumen dalam bentuk soal uraian terstruktur. Hasil uji coba soal uraian terstruktur pada kelas XI IA-1 MAN Model Palangka Raya mendapatkan tingkat validitas rata-rata 0,536 dan tingkat reliabilitas soal 0,539 dengan kategori cukup. Hasil penelitian menunjukkan bahwa: (1) peserta didik yang mampu dan tidak mengalami masalah dalam mengerjakan soal-soal uraian terstruktur berjumlah 18 peserta didik dan 12 peserta didik tidak mampu dan mengalami masalah dalam mengerjakan soal-soal uraian terstruktur. Peserta didik yang mampu mengerjakan soal-soal uraian terstruktur memiliki ketuntasan belajar ≥ batas KKM, yaitu 60% (2) kesulitan peserta didik dalam mengerjakan soal-soal uraian terstruktur terdapat pada penyebutan dan penulisan satuan besaran pada jawaban dengan persentase kesulitan 36,7%, penguasaan operasi hitungan denganpersentase kesulitan 31,4% dan penulisan besaran yang ditanya dalam soal dengan persentase kesulitan 28,6%

FIRST CRYOMODULE TEST AT AMTF HALL FOR THE EUROPEAN X-RAY FREE ELECTRON LASER (XFEL)

Abstract The Accelerator Module Test Facility (AMTF) at DESY in Hamburg is dedicated to the tests of RF cavities and accelerating cryomodules for the European X-ray Free Electron Laser (XFEL). The AMTF hall is equipped with two vertical cryostats, which are used for RF cavities testing and three test benches that will be used for tests of the accelerating cryomodules. Recently, the first cryomodule teststand (XATB3) was commissioned and the first XFEL cryomodule (XM-2) was tested by team of physicists, engineers and technicians from The Henry