Dimensionless scaling of heat-release-induced planar shock waves in near-critical CO2

We performed highly resolved one-dimensional fully compressible Navier-Stokes simulations of heat-release-induced compression waves in near-critical CO2. The computational setup, inspired by the experimental setup of Miura et al., Phys. Rev. E, 2006, is composed of a closed inviscid (one-dimensional) duct with adiabatic hard ends filled with CO2 at three supercritical pressures. The corresponding initial temperature values are taken along the pseudo-boiling line. Thermodynamic and transport properties of CO2 in near-critical conditions are modeled via the Peng-Robinson equation of state and Chung's Method. A heat source is applied at a distance from one end, with heat release intensities spanning the range 10^3-10^11 W/m^2, generating isentropic compression waves for values < 10^9 W/m^2. For higher heat-release rates such compressions are coalescent with distinct shock-like features (e.g. non-isentropicity and propagation Mach numbers measurably greater than unity) and a non-uniform post-shock state is present due to the strong thermodynamic nonlinearities. The resulting compression wave intensities have been collapsed via the thermal expansion coefficient, highly variable in near-critical fluids, used as one of the scaling parameters for the reference energy. The proposed scaling applies to isentropic thermoacoustic waves as well as shock waves up to shock strength 2. Long-term time integration reveals resonance behavior of the compression waves, raising the mean pressure and temperature at every resonance cycle. When the heat injection is halted, expansion waves are generated, which counteract the compression waves leaving conduction as the only thermal relaxation process. In the long term evolution, the decay in amplitude of the resonating waves observed in the experiments is qualitatively reproduced by using isothermal boundary conditions.Comment: As submitted to AIAA SciTech 2017, available at http://arc.aiaa.org/doi/pdf/10.2514/6.2017-008

A First-Principles Study of the Electronic Reconstructions of LaAlO3/SrTiO3 Heterointerfaces and Their Variants

We present a first-principles study of the electronic structures and properties of ideal (atomically sharp) LaAlO3/SrTiO3 (001) heterointerfaces and their variants such as a new class of quantum well systems. We demonstrate the insulating-to-metallic transition as a function of the LaAlO3 film thickness in these systems. After the phase transition, we find that conduction electrons are bound to the n-type interface while holes diffuse away from the p-type interface, and we explain this asymmetry in terms of a large hopping matrix element that is unique to the n-type interface. We build a tight-binding model based on these hopping matrix elements to illustrate how the conduction electron gas is bound to the n-type interface. Based on the `polar catastrophe' mechanism, we propose a new class of quantum wells at which we can manually control the spatial extent of the conduction electron gas. In addition, we develop a continuous model to unify the LaAlO3/SrTiO3 interfaces and quantum wells and predict the thickness dependence of sheet carrier densities of these systems. Finally, we study the external field effect on both LaAlO3/SrTiO3 interfaces and quantum well systems. Our systematic study of the electronic reconstruction of LaAlO3/SrTiO3 interfaces may serve as a guide to engineering transition metal oxide heterointerfaces.Comment: 50 pages, 18 figures and 4 table

Multi-elemental speciation analysis of barley genotypes diering in tolerance to cadmium toxicity using SEC-ICP-MS and ESI-TOF-MS

Plants respond to Cd exposure by synthesizing heavy-metal-binding oligopeptides, called phytochelatins (PCs). These peptides reduce the activity of Cd2+ ions in the plant tissues by forming Cd chelates. The main objective of the present work was to develop an analytical technique, which allowed identication of the most prominent Cd species in plant tissue by SEC-ICP-MS and ESI-TOF-MS. An integrated part of the method development was to test the hypothesis that dierential Cd tolerance between two barley genotypes was linked to dierences in Cd speciation. Only one fraction of Cd species, ranging from 7001800 Da, was detected in the shoots of both genotypes. In the roots, two additional fractions ranging from 29004600 and 670015 000 Da were found. The Cd-rich SEC fractions were heart-cut, de-salted and demetallized using reversed-phase chromatography (RPC), followed by ESI-MS-TOF to identify the ligands. Three dierent families of PCs, viz. (gGlu-Cys)n-Gly (PCn), (gGlu-Cys)n-Ser (iso-PCn) and Cys-(gGlu-Cys)n-Gly (des-gGlu-PCn), the last lacking the N-terminal amino acid, were identied. The PCs induced by Cd toxicity also bound several essential trace elements in plants, including Zn, Cu, and Ni, whereas no Mn species were detected. Zn, Cu and Ni-species were distributed between the 7001800 Da and 670015 000 Da fractions, whereas only Cd species were found in the 29004600 Da fraction dominated by PC3 ligands. Although the total tissue concentration of Cd was similar for the two species, the tolerant barley genotype synthesized signicantly more CdPC3 species with a high Cd specicity than the intolerant genotype, clearly indicating a correlation between Cd tolerance and the CdPC speciation

Novel Precursors for Boron Nanotubes: The Competition of Two-Center and Three-Center Bonding in Boron Sheets

We present a new class of boron sheets, composed of triangular and hexagonal motifs, that are more stable than structures considered to date and thus are likely to be the precursors of boron nanotubes. We describe a simple and clear picture of electronic bonding in boron sheets and highlight the importance of three-center bonding and its competition with two-center bonding, which can also explain the stability of recently discovered boron fullerenes. Our findings call for reconsideration of the literature on boron sheets, nanotubes, and clusters.Comment: 4 pages, 4 figures, 1 tabl

Interference of Malay Manado Language Toward Indonesian Language by Students' Speech in Gorontalo State University

Interference of Malay Manado Language in Formal Spoken Indonesian Language:&nbsp; “A Case Study at Indonesian Language Studies, Gorontalo State University†.This research aims to elaborate the kinds of interference in Malay Manado Language toward Indonesian Language on students’ speech in class discussion performance and to describe the most frequent of interference that students produced in class discussion performance by students in Indonesian Language Studies. Besides, the purpose of this research is to disclose the students deal with the interference on their speech in class discussion performance.The research was conducted in Indonesian Language Studies, Gorontalo State University. The data were collected from students’ speech in class discussion performance by using recording technique. The samples were 30 respondents. Two methods in analyzing data, namely descriptive quantitative and qualitative methods. There are three kinds of interference that students produced on students’ speech in class discussion performance namely phonological interference, morphological interference, and lexical interference. Firstly, in phonological interference can be categorized into assimilation, merger colescence or diftong, syncope, apocope, compression, and vowel modification. In morphological interference, they produced prefix addition, imperative form, reduplication, compounding form, and negation form. In Lexical interference, they created nine types of interference namely verb, noun, adjective, pronoun, adverb, question form, language particle, possesive, and preposition. Secondly, the most frequent type of interference on students’ speech in class discussion performance is lexical interference. It is about 193 in the percentage 59.38 %. Lastly, there are some factors that causing interference&nbsp; on students’ speech. They are, bilingualism, the lack of using Indonesian Language,&nbsp; needs for synonyms and the last is students’ high prestige

Adaptive spatial mode of space-time and spacefrequency OFDM system over fading channels

In this paper we present a 2 transmit 1 receive (1 Tx : 1 Rx) adaptive spatial mode (ASM) of space-time (ST) and space-frequency (SF) orthogonal frequency division multiplexing (OFDM). At low signal to noise ratio (SNR) we employ ST-OFDM and switch to SF-OFDM at a certain SNR threshold. We determine this threshold from the intersection of individual performance curves. Results show a gain of 9 dB (at a bit error rate of 10-3) is achieved by employing adaptive spatial mode compared to a fixed ST-OFDM, almost 6 dB to fixed SF-OFDM, 4 dB to Coded ST-OFDM and 2 dB to a fixed coded SF-OFDM, at a delay spread of 700 ns

Analisis Tingkat Kesejahteraan Rumah Tangga Nelayan Purse Seine Di Ppi Bulu Kabupaten Tuban Jawa Timur

Penelitian ini bertujuan untuk menganalisis tingkat kesejahteraan nelayan juragan dan ABK purse seine di PPI Bulu Kabupaten Tuban, Jawa Timur. Metode yang digunakan adalah metode deskriptif yang bersifat survei dengan pendekatan kuantitatif. Teknik pengambilan sampel menggunakan metode simple random sampling. Teknik pengumpulan data dilakukan dengan metode wawancara mendalam yang dilengkapi daftar kuisioner dan juga observasi langsung di lapangan. Teknik analisis data menggunakan 12 indikator kemiskinan gabungan yang terdiri dari indikator kemiskinan menurut Badan Pusat Statistik Pusat (2007), Badan Pusat Statistik Pusat 2006), indikator kemiskinan menurut Honable (1979) dalam Mc. Crackem (1988), indikator kemiskinan menurut Pridaningsih (2011), indikator kemiskinan menurut Safitri (2011), serta konsep Nilai Tukar Nelayan (NTN). Hasil penelitian menunjukkan bahwa tingkat kesejahteraan nelayan yang dianalisis menggunakan 12 indikator kemiskinan gabungan menunjukkan bahwa nelayan termasuk ke dalam kriteria tidak miskin atau tergolong sejahtera. Sedangkan hasil analisis tingkat kesejahteraan nelayan berdasarkan konsep Nilai Tukar Nelayan (NTN) secara simultan yaitu sebesar 1,22 (NTN &gt; 1), yang menunjukkan bahwa nelayan termasuk dalam kriteria tidak miskin atau tergolong sejahtera. Analisis secara parsial, NTN juragan sebesar 1,20 (NTN &gt; 1) dan NTN ABK sebesar 1,27 (NTN &gt; 1) yang menunjukkan nelayan juragan dan ABK termasuk dalam kriteria tidak miskin