Effects of superimposed eigenstrains on the overall thermoelastic moduli of composites

International audienceThis study investigates the effects that an initial local eigenstrain field, when superimposed on the thermal eigenstrain field, has on the overall thermal expansion coefficients and heat capacities of thermoelastic composites. The study can also be seen as an investigation into how a local residual stress field affects these overall moduli, as initial eigenstrains are generally a source of residual stresses. The approach taken is thermo-dynamic. Expressions that include the superimposed eigenstrain field are developed for the overall moduli within the framework of small strain ther-moelasticity with temperature dependent materials. These expressions, which are written in terms of the concentration tensors and residual fields (stress and strain fields given rise to by the eigenstrains under zero overall stress and strain, respectively), contain correction terms that are absent in the expressions developed within linear thermoelasticity. Taking into account the temperature dependence of the constituent moduli is shown to be essential to capture the effects of the superimposed eigenstrain field. A Ti-6Al-4V/ZrO2 composite is investigated for which the correction terms are found to be negligible for the heat capacities but significant for the thermal expansion coefficients. This suggests that, for applications with large temperature changes, using the linear-thermoelasticity-based expressions can affect the accuracy of the estimates of the overall mod-uli, and therefore the accuracy of thermostructural analyses of composite structures. The proposed expressions can be of use to estimate the overall thermoelastic moduli in contexts in which the strains remain small, temperature changes are large, and superimposed eigenstrains may be present

Terpaan dan Motif Pemanfaatan MPLIK Masyarakat di Kabupaten Pinrang

Mobile Pusat Layanan Internet Kecamatan (MPLIK) dirancang agar masyarakat di daerah bisa menikmati akses internet seperti masyarakat perkotaan. Adanya MPLIK diharapkan dapat meminimalisir kesenjangan informasi antara masyarakat di daerah dengan perkotaan. Program nasional MPLIK dicanangkan di 5.748 kecamatan di seluruh Indonesia. Namun Kenyataan yang ada saat ini literasi media teknologi informasi dan komunikasi (TIK) pada masyarakat di pedesaan masih sangat minim. Karena itu penelitian ini bertujuan untuk mengetahui terpaan dan motif pemanfaatan MPLIK pada masyarakat di Kabupaten Pinrang. Metode penelitian yang digunakan dalam penelitian in adalah survey dengan dua pendekatan yaitu kuantitatif dan kualitatif. Hasil penelitian menunjukkan bahwa terpaan MPLIK pada masyarakat di Kabupaten Pinrang termasuk dalam kategori cukup optimal. Hal ini dapat dilihat dari selektifitas, kesengajaan (tujuan dan manfaat), keterlibatan (frekuensi dan durasi), keterlibatan dan keyakinan dalam pemanfaatan MPLIK. Sedangkan motif pemanfaatan MPLIK pada masyarakat adalah ekonomi dan motif informatif. Motif ekonomi terlihat dari alasan responden memilih berkunjung ke MPLIK karena tarif yang lebih murah dan lokasi yang dekat serta nyaman. Sedangkan motif informatif tampak dari tujuan berinternet untuk mencari informasi umum

Derivation of Test Cases for LAP-B from a LOTOS Specification

this paper, we show how this method has been applied to obtain test cases for LAP-B that are comparable, and in fact occasionally better, than those obtained by [KLPU][Kan]. Since TTCN is a common language for the spec- ification of test trees, the test cases obtained are written in TTCN (we should observe, however, that LOTOS itself appears to be adequate for the specification of test trees [Steen]). This technique appears to be valuable for conformance testing, at least until such time as the more formal approaches being developed by other authors become available (see Section 7). It makes it possible to extract test cases directly from (possibly standardized) formal descriptions, eliminating or reducing the importance of the interpretation of the informally specified standard. The formal specification is more complete and precise than the state tables and, unlike the latter, allows full formal treatment of the data part. For example, we shall show that automatic or semiautomatic generation of frame values appear to be possible by using the information contained in selection predicates

MEDIA DIGITAL SEBAGAI AGENT OF CHANGE DALAM MEMPERTAHANKAN BUDAYA SIRI NA PACCE DI MASYARAKAT KOTA MAKASSAR

Media digital dapat menjadi agent of change dalam menyebarluaskan ide dan gagasan dalam melakukan perubahan terkait pemahaman masyarakat tentang budaya siri na pacce sebagai budaya menampilkan kekerasan. Metode yang digunakan adalah deskriptif kuantitatif dengan teknik penarikan sampel menggunakan accidental sampling. Hasil penelitian menyimpulkan bahwa responden media digital dapat berperan sebagai agent of change khususnya dalam memahami budaya siri na pacce sebagai nilai-nilai budaya yang beradab di tengah-tengah masyarakat Bugis-Makassar. Keberadaan media digital sebagai agent of change dapat dilihat dari adanya berbagai informasi yang diberikan yang berfungsi sebagai penghubung dalam menyampaikan informasi kepada masyarakat dalam memberikan pemahaman sehingga budaya siri na pacce tidak lagi sebagai budaya kekerasan jika dilanggar tetapi sebagai budaya untuk menjaga nilai-nilai adil dan beradab dalam budaya Bugis-Makassar

Elastic perfectly plastic oscillator under random loads: Linearization and response power spectral density

International audienceThe randomly-excited elastic-perfectly-plastic oscillator-hysteretic bilinear oscillator with zero secondary stiffness-has been extensively researched. The vast majority of the work on that system has investigated the time-domaine statistics of the response. No studies have focused on the power spectral densities. This study specifically examines the system's velocity power spectral density-the system's displacement is nonstationary-under wide-band random excitations by means of a statistical linearization/stochastic averaging technique that is developed in one existing and two new procedures, one with constant, the other with amplitude-dependent parameters. The three procedures are evaluated against Monte Carlo simulation and classical Gaussian linearization in terms of the velocity average power, the peak frequency of the power spectral density, its peak value, its bandwidth, and its overall shape around the main frequency. The best predictions were yielded by the new procedure with amplitude-dependent parameters, which combines an extended amplitude-phase transformation, a linearization with random parameters into a Maxwell system, a correlation-function-based criterion, the conditional power spectral density concept, and a power conservation correction step. The new procedures can be adapted to apply to other hysteretic systems

Numerical study of the effects of crown discharge on the separation bulbs of the leading edge with low Reynolds numbers

Surface atmospheric plasmas can act on the boundary layer of a flow along a profile. Different types of plasma actuators are currently being studied in specialized laboratories. The objectives in the aerodynamic domain can be to control the laminar-turbulent transition, the decrease in drag, the increase in lift, the reduction of noise and consumption.The object of this work is to use plasma actuators by characterizing their physical properties and their effects on flows. Two configurations were used: surface discharges with strip electrodes and wire electrodes. The ionic wind induced by these actuators is of low speed (a few m/s). This mechanical property was used to modify the boundary layer developing on a flat plate. The leading edge detachments from the profile flow have been delayed or even eliminated. The digital modeling and resolution of flow subjected to surface corona discharges, consists of a study based on the numerical simulation of the stationary behavior of a corona discharge in air at atmospheric pressure, carried out using the FLUENT software

Numerical study of the effects of crown discharge on the separation bulbs of the leading edge with low Reynolds numbers

Surface atmospheric plasmas can act on the boundary layer of a flow along a profile. Different types of plasma actuators are currently being studied in specialized laboratories. The objectives in the aerodynamic domain can be to control the laminar-turbulent transition, the decrease in drag, the increase in lift, the reduction of noise and consumption.The object of this work is to use plasma actuators by characterizing their physical properties and their effects on flows. Two configurations were used: surface discharges with strip electrodes and wire electrodes. The ionic wind induced by these actuators is of low speed (a few m/s). This mechanical property was used to modify the boundary layer developing on a flat plate. The leading edge detachments from the profile flow have been delayed or even eliminated. The digital modeling and resolution of flow subjected to surface corona discharges, consists of a study based on the numerical simulation of the stationary behavior of a corona discharge in air at atmospheric pressure, carried out using the FLUENT software

SIMULASI MONTE CARLO DALAM PENENTUAN HARGA OPSI BARRIER

Opsi yang terdapat pada pasar keuangan ada bermacam-macam, antara lain : opsi Amerika, opsi Eropa, dan juga opsi eksotik seperti opsi barrier, opsi Asia, dan lain-lain. Banyak model telah ditemukan untuk menentukan harga opsi-opsi tersebut. Untuk opsi barrier, dapat ditentukan salah satunya dengan simulasi Monte Carlo. Simulasi Monte Carlo digunakan untuk menaksir interval harga opsi barrier, yang mana harga opsi barrier diprediksi berada pada interval tersebut. Kata kunci : simulasi Monte Carlo, Opsi Barrier

Internet dan Masyarakat Marginal di Kota Makassar; Studi Kasus Pemanfaatan Galeri Internet Bbppki

This research aims to know the knowledge and attitudes marginal users gallery internet in Balai Besar Pengkajian dan Pengembangan Komunikasi dan Informatika Makassar in Makassar city and effort BBPPKI Makassar.in overcoming the digital gap between city and marginalized communities in the city Makassar.Method used in the research is a method of qualitative description,to examine knowledge and attitudes marginal users BBPPKI Makassar. Research informants and Key informants deliberately obtained. Than through the observation,data collection is also done through in-depth in terviews with key informants,and informants, and the study of the document.Results of research show that knowledge has not been marginalized people maximum and still need help from the employee of internet gallery.From knowledge of aspects of the changes occurred mainly after the visitors gallery gallery utilize the increased knowledge,because guidance for free while aspects of behavior BBPPKI to overcome the digital gap in the socialization is done through electronic media,mass media and interpersonal communication