Numerical Implementation of Isotropic Consolidation of Clayey Soils

This paper reports on implementation of several numerical techniques to solve a set of governing equations resulting from simple one dimensional isotropic consolidation of soils that behave according to the Cam clay model. Three different methods of solving the equations of consolidation, namely the collocation method, the finite volume method and the finite element method, are presented. Apart from evaluating their efficiency, which becomes particularly crucial when implementing these techniques in the framework of an optimization problem aimed at tuning the model parameters, a set of parameters of a Cam clay model driving the time dependent response of the soils (deformation dependent variation of the coefficient of permeability and preconsolidation pressure) is also discussed

Basel II, External Ratings and Adverse Selection

This paper will describe and analyse the development of Basel II Capital Accord and will focus on the use of external ratings in the Standardized Approach in Basel II. Furthermore it will examine the problem of adverse selection which appears in Basel II as a result from the proposal for the use of external ratings in determining the risk weights in the standardized approach. The paper will also attempt to find possible solutions to the adverse selection problem by discussing two similar models, and derive implications from them.Basel II, external ratings, adverse selection, rating agencies, standardized approach

UPAYA GURU DALAM MENINGKATKAN HASIL BELAJAR SISWA MATA PELAJARAN IPA PADA POKOK BAHASAN PERUBAHANWUJUD BENDA DENGAN MENGGUNAKAN MODEL PEMBELAJARAN INKUIRI (PTK di Kelas IVMI Al Washliyah Perbutulan Kecamatan Sumber Kabupaten Cirebon)

Yuyun Yuniah : Siswa kelas IV MI Al Washliyah Perbutulan Kecamatan Sumber Kabupaten Cirebon, pada hasil nilai ulangan harian IPA pada pokok bahasan perubahan wujud benda, masih banyak siswa yang tidak tuntas belajar, 21 dari 30 siswa nilainya masih di bawah KKM (Kriteria Ketuntasan Minimal). Nilai KKM IPA kelas IV tahun ajaran 2012/2013 adalah 70. Siswa kelas IV juga memiliki karakteristik aktivitas siswa yang pasif, yaitu siswa kurang komunikatif dengan guru dan teman sekelasnya. Selama pembelajaran IPA, keterlibatan siswa jarang di libatkan dalam praktikum. Untuk mengatasi permasalahan ini, maka diperlukan suatu model pembelajaran yang banyak melibatkan siswa sehingga dapat meningkatkan aktivitas hasil dan ketuntasan belajar siswa. Salah satu model yang digunakan adalah model inkuiri pada pembelajaran IPA. Pengajaran berdasarkan inkuiri adalah suatu strategi yang berpusat pada siswa di mana kelompok siswa inkuiri kedalam suatu isu atau mencari jawabanjawaban terhadap isi pertanyaan melalui suatu prosedur yang digariskan secara jelas dan struktural kelompok. Tujuan dari penelitian ini adalah (1) Untuk mengkaji keberhasilan penerapan model inkuiri, pada proses pembelajaran IPA pada pokok bahasan perubahan wujud benda di kelas IV, MI Al Washliyah Perbutulan. (2) Untuk mengkaji hasil belajar siswa kelas IV MI Al Washliyah Perbutulan pada pelajaran Ilmu Pengetahuan Alam pada pokok bahasan perubahan wujud benda. (3) Seberapa besar pengaruh penggunaan inkuiri, dengan hasil dan ketuntasan belajar siswa pada pelajaran Ilmu Pengetahuan Alam pada pokok bahasan perubahan wujud benda di kelas IV MI Al Washliyah Perbutulan. Peneliti ini dilakukan di kelas IV MI Al Washliyah Perbutulan Kecamatan Sumber Kabupaten Cirebon, semester ganjil tahun 2012/2013 yang berjumlah 30 siswa dengan menggunakan desain penelitian tindakan kelas dalam dua siklus. Tiap-tiap siklus terdiri dari empat tahap yaitu perencanaan, pelaksanaan tindakan, pengamatan dan refleksi. Teknik pengumpulan data dilakukan dengan cara observasi, wawancara dan penilaian hasil belajar. Berdasarkan hasil penelitian diperoleh nilai rata-rata hasil belajar siswa pada siklus I adalah 61,33 dan siklus II adalah 79. Secara umum dapat disimpulkan bahwa pembelajaran inkuiri dapat meningkatkan aktivitas siswa

The shape of jamming arches in two-dimensional deposits of granular materials

We present experimental results on the shape of arches that block the outlet of a two dimensional silo. For a range of outlet sizes, we measure some properties of the arches such as the number of particles involved, the span, the aspect ratio, and the angles between mutually stabilizing particles. These measurements shed light on the role of frictional tangential forces in arching. In addition, we find that arches tend to adopt an aspect ratio (the quotient between height and half the span) close to one, suggesting an isotropic load. The comparison of the experimental results with data from numerical models of the arches formed in the bulk of a granular column reveals the similarities of both, as well as some limitations in the few existing models.Comment: 8 pages; submitted to Physical Review

Advances in green leases and green leasing: evidence from Sweden, Australia, and the UK

Improving the environmental performance of non-domestic buildings is a complex problem due to the participation of multiple stakeholders. This is particularly challenging in tenanted spaces, where landlord and tenant interactions are regulated through leases that traditionally ignore environmental considerations. ‘Green leasing’ has been conceptualized as a form of ‘middle-out’ inter-organisational environmental governance that operates between organisations, alongside other drivers. Green leases form a valuable framework for tenant–landlord cooperation within properties and across portfolios. This paper offers a comparative international investigation of how leases are evolving to become ‘greener’ in Sweden, Australia, and the UK, drawing on experience from an IEA project on behaviour change and a UK project on energy strategy development. It considers how stakeholder retrofit opportunities and interactions in non-domestic buildings are shaped by the (1) policy context in each country (e.g., the EPBD, NABERS, and MEES) and (2) prevailing leasing practices in each country. Based on this analysis, the paper develops a new market segmentation framework to accentuate the different roles that public sector organisations and private property companies play as both tenants and landlords across countries. We suggest that national government policies assist the public sector in leading on better leasing practices, whereas international certification and benchmarking schemes (e.g., BREEAM & GRESB) may provide more fuel to private sector tenants and landlords. The paper concludes with a discussion of the fit between property portfolios and policies, suggesting that international green lease standards might assist multinational tenants and property owners in upgrading both their premises and their operational practices

Holomorphic anomaly equations and the Igusa cusp form conjecture

Let $S$ be a K3 surface and let $E$ be an elliptic curve. We solve the reduced Gromov-Witten theory of the Calabi-Yau threefold $S \times E$ for all curve classes which are primitive in the K3 factor. In particular, we deduce the Igusa cusp form conjecture. The proof relies on new results in the Gromov-Witten theory of elliptic curves and K3 surfaces. We show the generating series of Gromov-Witten classes of an elliptic curve are cycle-valued quasimodular forms and satisfy a holomorphic anomaly equation. The quasimodularity generalizes a result by Okounkov and Pandharipande, and the holomorphic anomaly equation proves a conjecture of Milanov, Ruan and Shen. We further conjecture quasimodularity and holomorphic anomaly equations for the cycle-valued Gromov-Witten theory of every elliptic fibration with section. The conjecture generalizes the holomorphic anomaly equations for ellliptic Calabi-Yau threefolds predicted by Bershadsky, Cecotti, Ooguri, and Vafa. We show a modified conjecture holds numerically for the reduced Gromov-Witten theory of K3 surfaces in primitive classes.Comment: 68 page

Determination of Abundant Metabolite Matrix Adducts Illuminates the Dark Metabolome of MALDI-Mass Spectrometry Imaging Datasets

: Spatial metabolomics using mass spectrometry imaging (MSI) is a powerful tool to map hundreds to thousands of metabolites in biological systems. One major challenge in MSI is the annotation of m/z values, which is substantially complicated by background ions introduced throughout the chemicals and equipment used during experimental procedures. Among many factors, the formation of adducts with sodium or potassium ions, or in case of matrix-assisted laser desorption ionization (MALDI)- MSI, the presence of abundant matrix clusters strongly increases total m/z peak counts. Currently, there is a limitation to identify the chemistry of the many unknown peaks to interpret their biological function. We took advantage of the co-localization of adducts with their parent ions and the accuracy of high mass resolution to estimate adduct abundance in 20 datasets from different vendors of mass spectrometers. Metabolites ranging from lipids to amines and amino acids form matrix adducts with the commonly used 2,5-dihydroxybenzoic acid (DHB) matrix like [M + (DHB-H2O) + H]+ and [M + DHB + Na]+ . Current data analyses neglect those matrix adducts and overestimate total metabolite numbers, thereby expanding the number of unidentified peaks. Our study demonstrates that MALDI-MSI data are strongly influenced by adduct formation across different sample types and vendor platforms and reveals a major influence of so far unrecognized metabolite−matrix adducts on total peak counts (up to one third). We developed a software package, mass2adduct, for the community for an automated putative assignment and quantification of metabolite−matrix adducts enabling users to ultimately focus on the biologically relevant portion of the MSI data