2,875 research outputs found

    Trajectory Deflection of Spinning Magnetic Microparticles, the Magnus Effect at the Microscale

    Get PDF
    The deflection due to the Magnus force of magnetic particles with a diameter of 80 micrometer dropping through fluids and rotating in a magnetic field was measured. With Reynolds number for this experiment around 1, we found trajectory deflections of the order of 1 degree, in agreement within measurement error with theory. This method holds promise for the sorting and analysis of the distribution in magnetic moment and particle diameter of suspensions of microparticles, such as applied in catalysis, or objects loaded with magnetic particles.Comment: 12 pages, 3 figures. Appendix with 6 figure

    Synthesis, characterisation and gas permeation studies on microporous silica and alumina-silica membranes for separation of propane and propylene

    Get PDF
    Microporous silica membranes are known to exhibit molecular sieving effects. However, separation of nearly equal sized molecules is difficult to carry out by size exclusion. Introducing sorption selectivity and keeping the kinetics favourable to facilitate a good contribution of permeation from sorption is a possible solution to enhance selectivity of adsorbing molecules. Results are presented in this paper on the synthesis of a microporous silica membrane with commendable permselectivity between helium and propylene. Modifications are performed on the membrane to improve its almost non-selective nature to propylene/propane mixtures to give practical separation values. Gas separation results on the modified membranes are presented. Surface selectivity on the newly added alumina surface layer is identified as the helping mechanism in realising this separation

    Excess portal venous long-chain fatty acids induce syndrome X via HPA axis and sympathetic activation

    Get PDF
    We tested the hypothesis that excessive portal venous supply of long-chain fatty acids to the liver contributes to the development of insulin resistance via activation of the hypothalamus-pituitary-adrenal axis (HPA axis) and sympathetic system. Rats received an intraportal infusion of the long-chain fatty acid oleate (150 nmol/min, 24 h), the medium-chain fatty acid caprylate, or the solvent. Corticosterone (Cort) and norepinephrine (NE) were measured as indexes for HPA axis and sympathetic activity, respectively. Insulin sensitivity was assessed by means of an intravenous glucose tolerance test (IVGTT). Oleate infusion induced increases in plasma Cort (Δ = 13.5 ± 3.6 µg/dl; P < 0.05) and NE (Δ = 235 ± 76 ng/l; P < 0.05), whereas caprylate and solvent had no effect. The area under the insulin response curve to the IVGTT was larger in the oleate-treated group than in the caprylate and solvent groups (area = 220 ± 35 vs. 112 ± 13 and 106 ± 8, respectively, P < 0.05). The area under the glucose response curves was comparable [area = 121 ± 13 (oleate) vs. 135 ± 20 (caprylate) and 96 ± 11 (solvent)]. The results are consistent with the concept that increased portal free fatty acid is involved in the induction of visceral obesity-related insulin resistance via activation of the HPA axis and sympathetic system.

    Composition profiling InAs quantum dots and wetting layers by atom probe tomography and cross-sectional scanning tunnelling microscopy

    Get PDF
    This study compares cross-sectional scanning tunnelling microscopy (XSTM) and atom probe tomography (APT). We use epitaxially grown self-assembled InAs quantum dots (QDs) in GaAs as an exemplary material with which to compare these two nanostructural analysis techniques. We studied the composition of the wetting layer and the QDs, and performed quantitative comparisons of the indium concentration profiles measured by each method. We show that computational models of the wetting layer and the QDs, based on experimental data, are consistent with both analytical approaches. This establishes a link between the two techniques and shows their complimentary behaviour, an advantage which we exploit in order to highlight unique features of the examined QD material.Comment: Main article: 8 pages, 6 figures. Appendix: 3 pages, 5 figure

    ANALISIS KREDIT BERMASALAH DITINJAU DARI NON PERFORMING LOAN (NPL) PADA PT BANK MANDIRI (PERSERO) TBK

    Get PDF
    Penelitian ini mempunyai tujuan untuk menilai seberapa besar kredit yang bermasalah jika ditinjau dari Non Performing Loan (NPL) di perusahaan perbankan yaitu PT Bank Mandiri (Persero) Tbk. Metode yang digunakan dalam penelitian ini adalah metode deskriptif. Sumber data yang digunakan adalah data sekunder dan menggunakan teknik studi kepustakaan dan observasi sebagai teknik pengumpulan data. Dalam penelitian ini menggunakan alat hitung rasio keuangan Non Performing Loan (NPL) sebagai teknik analisis data. Dari penelitian ini diperoleh kesimpulan bahwa rasio NPL tertinggi terjadi pada tahun 2016 yaitu sebesar 3.96% dan rasio NPL terendah terjadi pada tahun 2019 sebesar 2.39%. Rata-rata NPL selama 5 tahun dimulai dari tahun 2016-2020 yaitu sebesar 3.17% berada pada predikat sehat
    corecore