Effect of homogenisation conditions on recrystallisation in the Al-Mg-Mn alloy AA5454

The purpose of the present work is to understand the microstructure development and, particularly, to control the progress of recrystallisation in hot strip in the Al-Mg-Mn alloy AA 5454, which is typically used for the manufacture of structural automotive components. The chemical composition, together with the thermomechanical processing history of this material, has a strong influence on the microstructure of the product and the resulting properties as it is supplied to the customer. Electrical conductivity measurements, thermal analysis and electron microscopy have been carried out to characterise the evolution of precipitation state at various stages in the processing route. The conditions of the homogenisation heat treatment have been varied, and the effect on subsequent recrystallisation after hot rolling has been evaluated in both the as cast and rough rolled condition by optical microscopy techniques. Results indicate that the conditions of homogenisation heat treatment and roughing rolling are critical for the generation of a suitable recrystallised microstructure in AA 5454 hot strip. A new two stage homogenisation practice has been developed to expedite post-rolling recrystallisation in this alloy

Manajemen Mutu Kinerja Dosen Politeknik Kesehatan

Kompetensi rendah dari Politeknik Ilmu Kesehatan lulusan di Indonesia saat ini sedang dalam sorotan.. Berdasarkan penelaahan teoritis, kompetensi rendah dari lulusan disebabkan oleh rendahnya kinerja dosen. Dari sudut pandang teoritis, kinerja rendah dari dosen dapat dipengaruhi oleh motivasi dosen, komitmen, kepemimpinan dan iklim organisasi. Berdasarkan kerangka ini, penulis tertarik untuk melakukan penelitian kuantitatif melalui metode survei. Sampelnya adalah 161 dosen. Responden dari penelitian ini adalah dosen dan mahasiswa. Analisis jalur digunakan sebagai tehnik analisis. Hasil penelitian menunjukkan bahwa skor rata-rata kualitas kinerja dosen di Politeknik Ilmu Kesehatan adalah dalam kategori rata-rata. Aspek pengajaran dan pembelajaran proces lebih dominan dibandingkan dengan kinerja aspek penelitian dan pelayanan masyarakat. Temuan ini menegaskan praktek saat ini dosen yang masih memprioritaskan pengajaran dan pembelajaran, daripada kegiatan penelitian dan pengabdian masyarakat. Variabel motivasi berprestasi, dosen komitmen, perilaku kepemimpinan, dan variabel iklim organisasi mempengaruhi dosen kinerja baik simultan dan individual. Ini berarti bahwa kinerja dosen dipengaruhi oleh motivasi berprestasi, komitmen dosen, perilaku kepemimpinan, dan variabel iklim organisasi. Di antara empat variabel, motivasi berprestasi memiliki pengaruh kuat terhadap kinerja dosen. Penelitian ini menawarkan strategi hyphotetic alternatif untuk mengelola peningkatan kinerja dosen yang dapat digunakan oleh para pemimpin Politeknik Ilmu Kesehatan.The low competency of the Polytecnic of Health Sciences graduates in Indonesia is currently under the spotlight. Based on the theoretical review, the low competency of the graduates is caused by the low performance of the lecturers. From the theoretical point of view, the low performance of the lecturers can be influenced by the lecturers\u27 motivation, commitment, leadership and organizational climate. Based on this framework, the writer is interested to conduct the quantitative research through survey method. The population of the research is 268 lecturers and resulted in 161 lecturers as the sample. The respondents of this reseach are lecturers and students. Path analysis is used as the tehnique of analysis. The result of the research shows that the average score of the quality of the lecturers performance in the Polytecnic of Health Sciences is in average category. The aspect of teaching and learning proces is more dominant compared to the performance of the research and community services aspects. This finding confirms the current practice of the lecturers who still prioritize teaching and learning, rather than the research and community service activities. The variables of achievement motivation, lecturers\u27 commitment, leadership behavior, and organizational climate variables influence the lecturers\u27 performance both simultaniously and individually. It means that the lecturers\u27 performance is influenced by achievement motivation, lecturers\u27 commitment, leadership behavior, and organizational climate variables. Among the four variables, the achievement motivation has the strongest influence on the lecturers\u27 performance. This research offers an alternative hyphotetic strategy for managing the improvement of lecturers\u27 performance which can be used by the leaders of the Polytecnic of Health Sciences

Synthesis of Graphene on Gold

Here we report chemical vapor deposition of graphene on gold surface at ambient pressure. We studied effects of the growth temperature, pressure and cooling process on the grown graphene layers. The Raman spectroscopy of the samples reveals the essential properties of the graphene grown on gold surface. In order to characterize the electrical properties of the grown graphene layers, we have transferred them on insulating substrates and fabricated field effect transistors. Owing to distinctive properties of gold, the ability to grow graphene layers on gold surface could open new applications of graphene in electrochemistry and spectroscopy.Comment: 8 pages, 4 figure

Analysis of complex contagions in random multiplex networks

We study the diffusion of influence in random multiplex networks where links can be of $r$ different types, and for a given content (e.g., rumor, product, political view), each link type is associated with a content dependent parameter $c_i$ in $[0,\infty]$ that measures the relative bias type-$i$ links have in spreading this content. In this setting, we propose a linear threshold model of contagion where nodes switch state if their "perceived" proportion of active neighbors exceeds a threshold \tau. Namely, a node connected to $m_i$ active neighbors and $k_i-m_i$ inactive neighbors via type-$i$ links will turn active if $\sum{c_i m_i}/\sum{c_i k_i}$ exceeds its threshold \tau. Under this model, we obtain the condition, probability and expected size of global spreading events. Our results extend the existing work on complex contagions in several directions by i) providing solutions for coupled random networks whose vertices are neither identical nor disjoint, (ii) highlighting the effect of content on the dynamics of complex contagions, and (iii) showing that content-dependent propagation over a multiplex network leads to a subtle relation between the giant vulnerable component of the graph and the global cascade condition that is not seen in the existing models in the literature.Comment: Revised 06/08/12. 11 Pages, 3 figure

The geometric order of stripes and Luttinger liquids

It is argued that the electron stripes as found in correlated oxides have to do with an unrecognized form of order. The manifestation of this order is the robust property that the charge stripes are at the same time anti-phase boundaries in the spin system. We demonstrate that the quantity which is ordering is sublattice parity, referring to the geometric property of a bipartite lattice that it can be subdivided in two sublattices in two different ways. Re-interpreting standard results of one dimensional physics, we demonstrate that the same order is responsible for the phenomenon of spin-charge separation in strongly interacting one dimensional electron systems. In fact, the stripe phases can be seen from this perspective as the precise generalization of the Luttinger liquid to higher dimensions. Most of this paper is devoted to a detailed exposition of the mean-field theory of sublattice parity order in 2+1 dimensions. Although the quantum-dynamics of the spin- and charge degrees of freedom is fully taken into account, a perfect sublattice parity order is imposed. Due to novel order-out-of-disorder physics, the sublattice parity order gives rise to full stripe order at long wavelength. This adds further credibility to the notion that stripes find their origin in the microscopic quantum fluctuations and it suggests a novel viewpoint on the relationship between stripes and high Tc superconductivity.Comment: 29 pages, 14 figures, 1 tabl

Penerapan Safety Management System Pada Lembaga Penyelenggara Pelayanan Navigasi Penerbangan Indonesia

This study aimed to analyze the effect of the implementation of Safety Management System (SMS) and the use of information system on the Flight Safety in the Indonesian Air Navigation Services Organization both partially and simultaneously. The research uses quantitative methods, and the data are analyzed using linear regression, simple correlation both partially and simultaneously and path analysis. The result shows; implementation of Safety Management System (X1) as measured by the Flight Safety (Y) has a positive and significant contribution on the level of Flight Safety. The amount of the application contribution of Safety Management System that directly contributes to the Flight Safety is 35.4%, so the research hypothesis which states that the Safety Management System application directly impacts significantly on Aviation Safety is accepted; the use of Information Systems (X2) as measured by the Flight Safety (Y) has a positive and significant contribution on the level of Flight Safety. The use of information systems contributions that directly contributes to aviation safety is 38.4%, so the hypothesis which states that the use of information system directly affects significantly the flight safety is acceptable; the total effect of simultaneous application of Safety Management System (X1) and the use of Information Systems (X2) contribute significantly to the Flight Safety (Y) as much as 66.3%. The remaining 33.7% is the influence of the other factors such as refresher and development training for air navigation personnel, aviation navigation equipment renewal and observation fligh

Pengembangan Instrumen Antecedent Gap ServQual

Di tengah-tengah persaingan yang demikian ketat, dengan menggunakan metode Antecedent Gap ServQual dan deskriptif analisis, maka, tampak dengan jelas betapa keunggulan yang kompetitif menjadi acuan bagi segenap Awak Kabin