Origin of the Significant Impact of Ta on the Creep Resistance of FeCrNi Alloys

Heat resistant FeCrNi alloys are widely used in the petrochemical industry because they exhibit a unique combination of creep and oxidation resistance at temperatures exceeding 900$^\circ$C. Their creep properties are often optimized by micro-additions of carbide forming elements. In the present work, the influence of Ta micro-additions has been experimentally investigated both on as-cast and aged microstructures to understand the origin of the significant impact of this element on the creep resistance. Calculations with thermocal software were also carried out to support experimental data. It is shown that a small addition of Ta is beneficial as it increases the volume fraction of stable MC carbides. We demonstrate also that additions of Ta may have a dramatic effect on the thermal stability of microstructures. This is attributed to a smaller equilibrium volume fraction of M23C6 and more pronounced heterogeneous precipitation at MC/matrix interfaces. The influence on the creep properties in then discussed

A study of Al1-xInxN growth by reflection high-energy electron diffraction-incorporation of cation atoms during molecular-beam epitaxy

Molecular-beam epitaxy of Al1-x Inx N alloys with different indium (In) contents, x, were studied by in situ reflection high-energy electron diffraction (RHEED). Growth rates of the alloys were measured by the RHEED intensity oscillations for different source flux conditions, while the lattice parameters were derived from the diffraction patterns. It was found that under the excess nitrogen growth regime, incorporation of aluminum was complete whereas incorporation of In atoms was incomplete even at temperatures below 400 °C. © 2008 American Institute of Physics.published_or_final_versio

Transition between wurtzite and zinc-blende GaN: An effect of deposition condition of molecular-beam epitaxy

GaN exists in both wurtzite and zinc-blende phases and the growths of the two on its (0001) or (111) surfaces are achieved by choosing proper deposition conditions of molecular-beam epitaxy (MBE). At low substrate temperatures but high gallium fluxes, metastable zinc-blende GaN films are obtained, whereas at high temperatures and/or using high nitrogen fluxes, equilibrium wurtzite phase GaN epilayers resulted. This dependence of crystal structure on substrate temperature and source flux is not affected by deposition rate. Rather, the initial stage nucleation kinetics plays a primary role in determining the crystallographic structures of epitaxial GaN by MBE. © 2006 American Institute of Physics.published_or_final_versio

A Novel Physical Layer Secure Key Generation and Refreshment Scheme for Wireless Sensor Networks

Physical Layer Secure Key Generation (PL-SKG) schemes have received a lot of attention from the wireless security community in recent years because of the potential benefits that they could bring to the security landscape. These schemes aim to strengthen current security protocols by reducing the amount of key material that devices need for deployment. They do this by harnessing the common source of randomness provided by the wireless channel that the physical layer is communicating over. This is of particular importance in Wireless Sensor Networks (WSNs) where resources are particularly scarce and where issues such as key revocation and recovery make the design of efficient key management schemes extremely difficult. This paper discusses the issues and challenges encountered in the design and implementation of PL-SKG schemes on off-the-shelf wireless sensor networks. It then proposes a novel key generation scheme that takes advantage of both the power and simplicity of classic error correcting codes and also the diversity of frequency channels available on 802.15.4 compliant nodes to generate keys from received signal strength (RSS) readings. This paper shows that our key generation and refreshment scheme can achieve a near 100% key reconciliation rate whilst also providing perfect forward and backward security

EKSISTENSI PRINSIP SYURA DALAM KONSTITUSIONAL ISLAM

Pola syura (musyawarah) sebagai salah satu prinsip konstitusional dalam nomokrasi Islam, oleh para pemikir modern, dianggap sebagai doktrin kemasyarakatan dan kenegaraan yang pokok. Tidak saja karena jelas nasnya dalam Alquran , tetapi juga karena hal ini diperkuat oleh hadis, serta merupakan sunnah atau keteladanan Nabi. Dalam Islam, syura diletakkan sebagai prinsip utama dalam menyelesaikan masalah-masalah sosial, politik dan pemerintahan. Meskipun ihwal pelaksanaan Syura maupun pelembagaan syura, tidak ada nas Alquran yang memberikan paparan detail tentangnya. Namun pembentukan lembaga syura (legislatif) dalam sistem ketatanegaraan masyarakat muslim adalah sesuatu yang menjamin pencapaian tujuan-tujuan legislatif. Syura merupakan suatu sarana dan cara memberi kesempatan kepada anggota masyarakat yang mempunyai kemampuan untuk berpartisipasi dalam membuat keputusan yang sifatnya mengikat, baik dalam bentuk peraturan hukum maupun kebijakan politik

A Centralised Wi-Fi Management Framework for D2D Communications in Dense Wi-Fi Networks

In Wi-Fi networks, Device-to-Device (D2D) communications aim to improve the efficiency of the network by supporting direct communication between users in close proximity. However, in a congested Wi-Fi network, establishing D2D connections through a locally managed self-organising approach will intensify the congestion and reduce the scalability of the solution. Therefore, a centralised management approach must be involved in orchestrating those actions to guarantee the sufficiency of D2D communications. In this paper, we propose a novel management framework for D2D communications in dense Wi-Fi networks. The proposed framework employs a Software-Defined Networking (SDN) based centralised controller in synergy with a novel Access Point (AP) channel assignment process. This framework is designed to proactively establish and manage D2D connections in Wi-Fi networks considering the available radio resources and the effect of the subsequent interference. Thus, improving the overall performance of the network and providing users with higher data rate. Through simulation, we validate the effectiveness of the proposed framework and demonstrate how D2D deployment considerably improves the Wi-Fi network efficiency especially when the data rate requirements are high. Furthermore, we show that our proposed framework achieves better performance than the widely deployed Least Congested Channel selection strategy (LCC)

KEBIJAKAN REGULASI BAITUL MAAL WAT TAMWIL (BMT) DI INDONESIA

Sektor keuangan di Indonesia merupakan salah satu sektor yang memiliki peranan penting dalam mendorong peningkatan perekonomian nasional dan ekonomi masyarakat. maka, sudah barang tentu lembaga atau instansi yang berkecimpung di sektor keuangan memerlukan regulasi yang jelas sebagai aturan mainnya. Ironisnya BMT selaku salah satu lembaga keuangan mikro yang memiliki andil yang besar dan perkembangannya sangat signifikan khususnya dalam menjangkau perekonomian kelas menengah dan ke bawah justru cenderung kurang mendapat perhatian dari pemerintah khususnya mengenai regulasinya. Padahal regulasi merupakan salah satu faktor paling penting yang mempengaruhi sustainabilitas BMT selaku Lembaga Keuangan Mikro Syariah guna meningkatkan perekonomian nasional. Berangkat dari latar belakang tersebut, penelitian ini bertujuan untuk mengetahui, mengkaji dan menjelaskan bagaimana regulasi Baitul Maal Wat Tamwil (BMT) dalam Peraturan Perundang-Undangan Perkoperasian, Undang-Undang Yayasan, dan Undang-Undang Lembaga Keuangan Mikro serta mengapa kebijakan regulasi BMT yang ada seperti saat ini? Penelitian ini termasuk jenis penelitian hukum normatif, sedangkan spesifikasi penelitian ini adalah deskriptif analitis, yaitu penelitian yang menjelaskan keadaan yang terjadi dengan tujuan untuk memunculkan fakta yang diikuti dengan analisis dengan tujuan untuk menemukan jawaban atas permasalahan kebijakan regulasi BMT di Indonesia. Bahan hukum yang digunakan dalam meliputi bahan hukum primer, sekunder, dan tersier. Pengumpulan bahan hukum dalam penulisan ini ditempuh dengan melakukan penelitian kepustakaan dan studi dokumen. Pendekatan utama yang ditempuh adalah doktrinal. Dengan menggunakan teori kebijakan dan pembentukan serta asas-asas pemberlakuan peraturan perundang-undangan sebagai dasar analisisnya. Berdasarkan dari hasil penelitian yang penulis lakukan dapat disimpulkan sebagai berikut: 1. Pengaturan BMT dengan Undang-Undang Perkoperasian hanya bersifat sementara sampai dikeluarkannya Undang-Undang yang secara spesifik mengatur persoalan BMT. 2. Undang-Undang yayasan tidak bisa dijadikan dasar pengaturan BMT, dikarenakan yayasan merupakan lembaga yang hanya berorientasi pada kepentingan sosial, sedangkan BMT memiliki fungsi sosial sekaligus profit oriented. 3. Pengaturan BMT dalam Undang-Undang nomor 1 tahun 2013 tentang Lembaga Keuangan Mikro telah memberikan kejelasan tentangi apa dan bagaimana seharusnya kelembagaan BMT, pedoman aspek syariah, pengawasan, dan penjaminan simpanan nasabah, meskipun sampai saat ini belam ada Peraturan Pemerintah yang mengatur lebih lanjut bagaimana mekanisme penjaminan simpanan dalam lembaga keuangan mikro khususnya BMT. 4. Kebijakan regulasi BMT saat ini cenderung mendorong perkembangan BMT ke arah lembaga keuangan seperti halnya perbankan. Hal ini dikarenakan tidak adanya pemahaman mengenai hakikat dari konsep BMT oleh pemerintah, sehingga menyebabkan terjadinya pergeseran konseptual BMT

Different origins of visible luminescence in ZnO nanostructures fabricated by the chemical and evaporation methods

Zinc oxide nanostructures were fabricated using chemical and thermal evaporation methods. Scanning electron microscopy (SEM), x-ray diffraction, photoluminescence, and electron paramagnetic resonance (EPR) spectroscopy were used to study the properties of fabricated nanostructures. The nanostructures fabricated by evaporationg methods exhibited green PL from surface centers. The results show that the luminescence in the visible region has different peak positions in samples prepared by chemical and evaporation methods.published_or_final_versio

Copper(ii) complexes of N-propargyl cyclam ligands reveal a range of coordination modes and colours, and unexpected reactivity

The coordination chemistry of N-functionalised cyclam ligands has a rich history, yet cyclam derivatives with pendant alkynes are largely unexplored. This is despite the significant potential and burgeoning application of N-propargyl cyclams and related compounds in the creation of diversely functionalised cyclam derivatives via copper-catalysed azide–alkyne ‘click’ reactions. Herein we describe single crystal X-ray diffraction and spectroscopic investigations of the coordination chemistry of copper(II) complexes of cyclam derivatives with between 1 and 4 pendant alkynes. The crystal structures of these copper complexes unexpectedly reveal a range of coordination modes, and the surprising occurrence of five unique complexes within a single recrystallisation of the tetra-N-propargyl cyclam ligand. One of these species exhibits weak intramolecular copper-alkyne coordination, and another is formed by a surprising intramolecular copper-mediated hydroalkoxylation reaction with the solvent methanol, transforming one of the pendant alkynes to an enol ether. Multiple functionalisation of the tetra-N-propargyl ligand is demonstrated via a ‘tetra-click’ reaction with benzyl azide, and the copper-binding behaviour of the resulting tetra-triazole ligand is characterised spectroscopically

SmartTennisTV: Automatic indexing of tennis videos

In this paper, we demonstrate a score based indexing approach for tennis videos. Given a broadcast tennis video (BTV), we index all the video segments with their scores to create a navigable and searchable match. Our approach temporally segments the rallies in the video and then recognizes the scores from each of the segments, before refining the scores using the knowledge of the tennis scoring system. We finally build an interface to effortlessly retrieve and view the relevant video segments by also automatically tagging the segmented rallies with human accessible tags such as 'fault' and 'deuce'. The efficiency of our approach is demonstrated on BTV's from two major tennis tournaments.Comment: 10 pages, 4 figures, NCVPRIPG 2017 Accepted Paper (Best Paper Award Winner