2,646 research outputs found

    Anisotropic structural and optical properties of a-plane (11-20) AlInN nearly-lattice-matched to GaN

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    We report epitaxial growth of a-plane (11-20) AlInN layers nearly-lattice-matched to GaN. Unlike for c-plane oriented epilayers, a-plane Al_{1-x}In_{x}N cannot be simultaneously lattice-matched to GaN in both in-plane directions. We study the influence of temperature on indium incorporation and obtain nearly-lattice-matched Al_{0.81}In_{0.19}N at a growth temperature of 760^{o}C. We outline a procedure to check in-plane lattice mismatch using high resolution x-ray diffraction, and evaluate the strain and critical thickness. Polarization-resolved optical transmission measurements of the Al_{0.81}In_{0.19}N epilayer reveal a difference in bandgap of ~140 meV between (electric field) E_parallel_c [0001]-axis and E_perpendicular_c conditions with room-temperature photoluminescence peaked at 3.38 eV strongly polarized with E_parallel_c, in good agreement with strain-dependent band-structure calculations

    Simulation of brittle damage for fracture process of endodontically treated tooth

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    The mechanics of brittle damage in porcelain of an endodontically treated maxilla incisor tooth was simulated using finite element method (FEM). For this purpose a very complex composite structure of endodontically treated tooth is simulated under transverse loading. Three dimensional (3D) model of human maxilla incisor tooth root was developed based on Computed Tomography (CT) scan images. Crown, core cement, resin core, dental post, post cement and dentin were created using SolidWorks software, and then the model was imported into ABAQUS-6.9EF software for nonlinear behavior analysis. This study utilizes finite element method to simulate onset and propagation of crack in ceramic layer (porcelain) by the cause of both tension and compression loading related to complexity of the geometry of tooth implant. The simulation has been done using brittle damaged model available in ABAQUS/Explicit in quasi-static load condition. The load-displacement response of whole structure is measured from the top of porcelain by controlling displacement on a rigid rod. Crack initiated at the top of porcelain bellow the location of the rod caused by tension damage at equivalent load of 590 N. Damage in porcelain accounts for up to 63% reduction of whole structure stiffness from the undamaged state. The failure process in porcelain layer can be described by an exponential rate of fracture energy dissipation. This study demonstrated that the proposed finite element model and analysis procedure can be use to predict the nonlinear behavior of tooth implant

    Highly automatic quantification of myocardial oedema in patients with acute myocardial infarction using bright blood T2-weighted CMR

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    <p>Background: T2-weighted cardiovascular magnetic resonance (CMR) is clinically-useful for imaging the ischemic area-at-risk and amount of salvageable myocardium in patients with acute myocardial infarction (MI). However, to date, quantification of oedema is user-defined and potentially subjective.</p> <p>Methods: We describe a highly automatic framework for quantifying myocardial oedema from bright blood T2-weighted CMR in patients with acute MI. Our approach retains user input (i.e. clinical judgment) to confirm the presence of oedema on an image which is then subjected to an automatic analysis. The new method was tested on 25 consecutive acute MI patients who had a CMR within 48 hours of hospital admission. Left ventricular wall boundaries were delineated automatically by variational level set methods followed by automatic detection of myocardial oedema by fitting a Rayleigh-Gaussian mixture statistical model. These data were compared with results from manual segmentation of the left ventricular wall and oedema, the current standard approach.</p> <p>Results: The mean perpendicular distances between automatically detected left ventricular boundaries and corresponding manual delineated boundaries were in the range of 1-2 mm. Dice similarity coefficients for agreement (0=no agreement, 1=perfect agreement) between manual delineation and automatic segmentation of the left ventricular wall boundaries and oedema regions were 0.86 and 0.74, respectively.</p&gt

    Analisis Proksimat terhadap Kualitas Batubara di Kecamatan Tanah Grogot Kabupaten Paser Provinsi Kalimantan Timur

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    Salah satu dampak merugikan pada pemakaian batubara dalam industri adalah tingginya kandungan pengotor yang terdapat dalam batubara. Tujuan dari penelitian ini adalah untuk mengetahui persentase hasil analisis proksimatpada batubaradan untuk mengetahui pengaruhnya terhadap nilai kaloripada batubara. Dilakukan dengan cara mengambil sampel batubara yang akan dianalisis, dari sampel yang ada kemudian dipreparasi untuk menghasilkan sampel siap uji. Dari hasil uji analisis proksimat yang dilakukan dari lima sampel persentase yang didapatkan pada sampel pertama adalah kandungan air15,82%, abu2,90%, zat terbang 42,85%, karbon padat 38,6%dengan nilai kalori 5683 Kcal/kg, sampel kedua kandungan air 18,65%, abu 3,65%, zat terbang 41,76, karbon padat 36,1% dengan nilai kalori 5380 Kcal/kg, sampel ketiga kandungan air 16,89%, abu 2,90%, zat terbang 42,06, karbon padat 38,1% dengan nilai kalori 5635 Kcal/kg, sampel keempat kandungan air 18,48%,abu 3,65%, zat terbang 41,40, karbon padat 36,4% dengan nilai kalori 5380 Kcal/kg dan sampel kelima dengan kandungan air 15,82%, abu 3,09% zat terbang 42,91%, karbon padat 38,1% dengan nilai kalori 5643 Kcal/kg. Dari hasil yang diperoleh disimpulkan bahwa semakin tinggi kandungan airdan abumaka nilai kalori pada batubara akan semakin turun, dan pengaruh zat terbang menunjukan bahwa kadungan zat terbang yang rendah memiliki nilai kalori yang rendah. Sedangkan pengaruh karbon menunjukan bahwa semakin rendah kandungan karbon maka nilai kalori batubara semakin turun

    Reconsidering the Cultural Geographies of State and Non State Spaces

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    In Indonesia, the societies have a long history as a runaway society and fugitive from the state-making projects. Many historical accounts prove that people escape from the state projects, such as corvee labor, wars, diseases and epidemics, conscriptions, slavery, taxes, violence, warfare, diseases, and poverty. In general, this paper describes the state-society relations and examines the meaning of the non-governed society. This paper questions what distinguishes between govern and non-governed society, what kind of social economy and cultural life of non-governed society that distinguishes from a governed state? To answer these questions, this paper explores the distinction of the governed and the non-governed society, which live in the different geographical areas. This paper explains the distinctions and frictions between lowland and highland society in Indonesia, in terms of social economy, kinship, political organization, and religion. In the last reflection, the author argues that non governed society is not only people who live in the upland and far from the centralized bureaucracy, rather they also live in the middle of dense population of a town and even under a most centralized and autocratic regime

    Thermodynamics of mechanopeptide sidechains

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    Biological systems are often exposed to mechanical perturbations, which may modulate many biochemical processes. Ligand binding involves a wide range of structural changes in the receptor protein, from hinge movement of entire domains to minor sidechain rearrangements in the binding pocket residues. Hydrophobic ligand binding to protein alters the system’s vibrational free energy, allowing different conformational states of allosteric proteins. Excess hydrophobicity in protein–ligand binding generates mechanical force along the peptide backbone through the hydrophobic effect. We describe mechanically strained peptide structures involved in protein aggregation to determine the transition between the initial condensation of hydrophobic polypeptide chains into ordered fibrillar structures. This transition is due to the excess attractive hydrophobic force by ligand binding within proteins into fibrillar assemblies. The process of fibrillar formation has a mechanosensitive nature, which significantly influences the pathogenesis of several neurodegenerative diseases

    Analisa Posisi Bisnis Pelabuhan Kelas I pada PT Pelabuhan Indonesia IV (Persero) Menggunakan Strategi Tipology Miles And Snow

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    Eksistensi Perusahaan dalam pada Perubahan pasar atau kondisi tertentu menjadi sangat penting bagi semua Perusahaan karena mereka semua menjadi bagian dari globalisasi. Penelitian ini bertujuan untuk mengidentifikasi posisi bisnis pelabuhan kelas I di lingkungan PT Pelabuhan Indonesia IV (Persero);  meningkatkan keunggulan kompetitif unit bisnis pada masing-masing pelabuhan kelas I; dan  menentukan strategi yang efektif diterapkan bagi masing-masing pelabuhan kelas I. Penelitian ini dirancang untuk mengarahkan keputusan strategis pada pelabuhan kelas I. Keputusan strategi manajerial dalam penelitian ini dalam cakupan analisa GE (general electric) dan analisa tipologi Miles & Snow. Lokasi atau tempat penelitian di Balikpapan, Samarinda, Bitung, Ambon, dan Sorong. Data yang dikumpulkan mencakup data data sekunder. Populasi dan sampel dalam penelitian ini mencakup general manajer, manajer dan asisten manajer di kelima cabang pelabuhan yaitu Pelabuhan Balikpapan, Pelabuhan Samarinda, Pelabuhan Bitung, Pelabuhan Ambon dan Pelabuhan Sorong sebanyak 40 orang. Teknik analisis data menggunakan analisis RBV,SWOT, TOWS, General Electric, dan Miles & Snow. Hasil penelitian menunjukkan bahwa bisnis pelabuhan kelas I di lingkungan PT Pelabuhan Indonesia IV (Persero) secara umum berada pada posisi yang menguntungkan dengan potensi sumber daya yang memadai. Upaya meningkatkan keunggulan kompetitif unit bisnis pelabuhan kelas I dengan memaksimalkan seluruh kekuatan dan peluang yang dimiliki, dan sekaligus meminimalkan kelemahan dan ancaman. Berdasarkan analisis Miles and Snow yang digunakan maka berdasarkan indikator strategi fokus Pelabuhan Bitung, Ambon dan Sorong  menerapkan strategi prospector, Pelabuhan Balikpapan mengadopsi strategi defender, dan Pelabuhan Samarinda revelan dengan strategi analyzer

    Reconsidering the Cultural Geographies of State and Non State Spaces

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    Abstract In Indonesia, the societies have a long history as a runaway society and fugitive from the state-making projects. Many historical accounts prove that people escape from the state projects, such as corvee labor, wars, diseases and epidemics, conscriptions, slavery, taxes, violence, warfare, diseases, and poverty. In general, this paper describes the state-society relations and examines the meaning of the non-governed society. This paper questions what distinguishes between govern and non-governed society, what kind of social economy and cultural life of non-governed society that distinguishes from a governed state? To answer these questions, this paper explores the distinction of the governed and the non-governed society, which live in the different geographical areas. This paper explains the distinctions and frictions between lowland and highland society in Indonesia, in terms of social economy, kinship, political organization, and religion. In the last reflection, the author argues that non governed society is not only people who live in the upland and far from the centralized bureaucracy, rather they also live in the middle of dense population of a town and even under a most centralized and autocratic regime. Keywords: Geography of the Highland and Lowland, non Governed Society, Resistance, Anarchism.&nbsp
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