Dirac particle in the presence of plane wave and constant magnetic fields: Path integral approach

The Green function (GF) related to the problem of a Dirac particle interacting with a plane wave and constant magnetic fields is calculated in the framework of path integral via Alexandrou et al. formalism according to the so-called global projection. As a tool of calculation, we introduce two identities (constraints) into this formalism, their main role is the reduction of integrals dimension and the emergence in a natural way of some classical paths, and due to the existence of constant electromagnetic field, we have used the technique of fluctuations. Hence the calculation of the (GF) is reduced to a known gaussian integral plus a contribution of the effective classical action.Comment: 12 pages, no figure

PENERAPAN ALGORITMA APRIORI PADA APLIKASI POINT OF SALE DI CENTRAL JAVA MARKET UMKM CENTER JAWA TENGAH

Central Java Market (CJ Mart) merupakan perusahaan ritel dengan format minimarket. Aneka macam jenis produk UMKM yang ditawarkan dan tata letak produk yang masih dilakukan secara acak oleh CJ Mart membuat konsumen kesulitan dalam mencari produk yang diinginkan. Penggunaan aplikasi Point Of Sale pada CJ MART hanya digunakan sebagai alat transaksi dan kurang dipadani dengan penggunaan suatu sistem yang menganalisis pola prilaku konsumen dalam membeli produk untuk meningkatkan strategi pemasaran yang efektif dan untuk meningkatkan jumlah penjualan. Algoritma apriori adalah algoritma untuk menemukan pola frekuensi tertinggi dari teknik market basket analysis. Penelitian ini mengembangkan aplikasi point of sale dengan metode market basket analysis pada teknik data mining untuk menganlisis produk mana yang sering dibeli secara bersamaan oleh konsumen. Aplikasi ini menggunakan penerapan algoritma apriori dan dibangun dengan menggunakan bahasa pemrograman Visual Basic.Net dan DBMS Microsoft Access. Aplikasi ini berfungsi untuk melakukan transaksi serta menganalisis produk yang dibeli secara bersamaan dari data transaksi penjualan. Analisa yang dihasilkan berupa rule dengan pola “if then” beserta nilai confidence. Data yang digunakan adalah data tahun 2014 dan 2015 yang diperoleh dari Central Java Market UMKM Center Jawa Tengah. Hasil output dari penelitian ini adalah tabel rekomendasi dari produk yang dibeli secara bersamaan sehingga dapat memberikan pertimbangan bagi perusahaan untuk menata ulang kembali layout toko

Scattering wave functions for Aharonov-Bohm-Coulomb field: Path integral treatment

Exact Green's functions related to Dirac particle submitted to the combination of Aharonov-Bohm and Coulomb fields in (2+1) coordinate space are analytically calculated via path integral formalism in both global and local representations. The scattering normalized wavefunctions as well as the corresponding continuous energy eigenvalues are extracted following this approach. The interesting properties of the spinors are thus deduced after symmetrization. According to the symmetric form for the Green's function, it is shown that the equivalence with Dirac equation is undertaken with much ease. Some particular cases are also considered

Analyzing Competitive advantage indicators among telecom operators in Algeria: A comparative study

نهدف من خلال هذه الدراسة إلى قياس مدى وجود فروقات في مؤشرات الميزة التنافسية بين متعاملي الهاتف النقال في الجزائر. بالاستناد لثلاثة مداخل رئيسية من أجل الإجابة على الإشكالية الدراسة، وبالاعتماد على المنهج الوصفي والاستقرائي والمقارن، تم جمع البيانات بالاعتماد على أسلوب الاستبيان، موجه لعينة عشوائية متكونة من 153 موظفًا وبعض المقابلات القصيرة مع مديري متعاملي الهاتف النقال في الجزائر، وكذلك بعض التقارير حول سوق الاتصالات في الجزائر المنشورة من طرف سلطة ضبط البريد والاتصالات الالكترونية ARPCE ، وتوصلنا في آخر الدراسة لعدم وجود فروقات ذات دلالة إحصائية بين متعاملي الهاتف النقال في الجزائر تعزى لمؤشرات الميزة التنافسية وفقًا للعينة المدروسة.This study aims to measure the differences of competitive advantage indicators between telecom operators in Algeria. On the basis of three approaches; the descriptive, inductive and comparative approach, we tried to answer the main question and carry out the empirical study. For data collection, we use the questionnaire of sample of 153 employees and some short interviews with managers, as well as some reports about telecoms market published by ARPCE. To test the hypothesis, we use the one-way ANOVA test. Finally, we have found that there are no significant differences between telecom operators about competitive advantage indicators, according to the studied sample

Conductivity modeling of gas sensors based on copper phthalocyanine thin films

The main objective of this work is to study the electronic conductivity of copper phthalocyanine (CuPc) thin films in presence of certain strong oxidizing gases involved in air pollution, particularly NO2, for use as gas sensor devices. To achieve this objective, the first part presents a study of the conductivity evolution of these sensors, in order to find the optimal operating temperature and to improve the kinetics of adsorption of gas molecules on the surface of the thin layer. In a second step, we tried to develop a mathematical model that describes as closely as possible the electrical behavior of these sensors in order to simulate their operation and optimize their performances. Elovich models have been applied to both gas adsorption and desorption phases and have led to good similarities between theoretical and measured response curves.Keywords: Gas sensors - thin layer - phthalocyanine - conductivity - modelin

La stylistique de Charles Bally, une linguistique dynamique

Par sa stylistique particulière, Charles Bally nous fait découvrir l’essence de la pensée complexe, en ayant envisagé de systématiser le discours naturel de l’être humain dans ses multiples facies. A la recherche d’une possibilité de sens partagé entre sujets parlants, Bally pense pouvoir théoriser la complexité du langage, chose qui ne passe que par la théorisation de l’élémentarité dans le langage. Suivant en cela le mode de pensée saussurien qui consistait à théoriser la linguistique de la langue par analogie à d’autres structures naturelles comme l’exemple des échecs ou celui de la tige d’une plante. Ainsi l’analogie serait mon outil pour examiner le fait de langue de Bally et l’entropie de Boltzmann

Effect of artificial aging treatment on microstructure, mechanical properties and fracture behavior of 2017A alloy

The effect of artificial aging treatment on 2017A aluminum alloy microstructure, mechanical properties, and fracture behavior was investigated. The samples were taken from the as-received alloy and aged at 170 °C for 5, 10, 15, 20, and 30 hours. An optical microscope, scanning electron microscope (SEM), X-ray diffraction (XRD), microhardness and tensile strength tests were used to characterize mechanical and microstructural properties. The microstructural analysis revealed that as the aging treatment duration is increased, the size and density of precipitates grow larger and more numerous. According to X-ray diffraction measurements, the microstructural evolution caused by aging treatments is primarily due to an increase in precipitation of the hardening phase -Al2Cu. According to the tensile test results, the yield stress increases with increasing aging duration. The fracture surface analysis of failed specimens subjected to tensile loading revealed that the aging treatment conditions had a significant impact on the morphology and mode of fracture: the mixed-mode (ductile-brittle) failure was established for intermediate aging durations (aging at 170 °C for 15 and 20 h), and the intergranular fracture was found to be more pronounced when the aging duration is prolonged due to the coalescence of fine precipitates at the grain boundary

Étude de l´écoulement d´un fluide entre deux plans parallèles munis d´obstacles

Dans ce travail nous étudions numériquement l’écoulement d’un fluide newtonien entre deux plans parallèles adiabatiques, de largeur infinie, munis de deux obstacles identiques, générateurs de chaleur et placés sur la paroi supérieure. L’écoulement est supposé laminaire et stationnaire et la dissipation visqueuse dans le fluide ne sera pas prise en considération. En outre, les propriétés physiques du fluide ainsi que celles du solide sont considérées constantes et uniformes. Pour la résolution des équations de continuité, de l’impulsion et de l’énergie, nous avons utilisé la méthode des volumes finis. La résolution du couplage vitesse-pression se fait par l’algorithme SIMPLER et la validité du code numérique a été testée par comparaison avec les résultats tirés à partir de la littérature. L’influence du nombre de Reynolds, en termes de lignes de courants et nombre de Nusselt, a été étudiée. Les résultats obtenus montrent que la variation du nombre de Reynolds engendre des effets significatifs sur la structure de l’écoulement. En effet, la formation de zones de recirculation entre les deux obstacles ainsi qu’en aval du second obstacle a été observée. L’étendue de cette dernière augmente proportionnellement avec le nombre de Reynolds. De plus, l'effet du rapport de conductivité entre le fluide et le solide a été examiné en termes de nombre de Nusselt. Cet effet est plus prononcé sur le premier obstacle de plus les variations de ce nombre s'estompent à partir d'un rapport K = 50