Journal of Mathematical and Fundamental Sciences
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Beberapa Aspek Teori dan Pemakaian dalam Masalah Dekomposisi Singulir
Get PDFSari. Dekomposisi singular suatu matriks real dapat dipandang dari berbagai sudut. Dengan bantuan rangkaian dual, di sini akan dipandang dari sudut operator Escoutier yang berkaitan dengan matriks tersebut. Selanjutnya akan dikemukakan beberapa aspek yang diakibatkan oleh pandangan ini. Abstract. The singular decomposition of a real matrix can be approached from several points of view. Here we use the Escoufier's operator and the instrument called diagram of duality. With this instrument we can visualize all mathematical terms involved in that problem
Penutupan dengan Asbes Dapat Memperbaiki Sifat Mekanik dari Sambungan Baja dengan Las Busur Listrik
Get PDFRingkasan. Sifat-sifat mekanik yang penting dari sambungan las adalah kekuatan dan keuletan. Kedua sifat ini dapat diuji dengan pengujian tarik, pengujian takik dan pengujian kekerasan. Kedua sifat utama tersebut sangat tergantung dari perlakuan lanjut yang dikenakan pada sambungan yang dimaksud. Di dalam penelitian ini dibandingkan pengaruh dari tiga perlakuan lanjut terhadap kedua sifat mekanik tersebut di atas pada sambungan las baja dengan busur listrik. Ketiga perlakuan lanjut yang dimaksud adalah: (a) tanpa perlakuan apa-apa, (b) dipanaskan dalam tungku pada temperature 650'C selama setengah jam dan diikuti dengan pendinginan di dalam tungu dan (c) ditutup dengan asbes segera setelah selesai pengelasan lapisan las yang terakhir. Hasil penelitian menunjukkan bahwa penutupan dengan asbes menghasilkan sifat-sifat mekanik yang lebih baik dari pada pengelasan yang tidak diikuti dengan perlakuan apa-apa, walaupun belum menyamai hasil dari pengelasan yang mendapat perlakuan lanjut dengan pemanasan di dalam tungku. Abstract. The important mechanical properties in welding technology are strength and ductility of the welded joint. These two properties can be examined through tensile testing, impact testing and hardness testing. It has been known that those two properties are influenced by the post treatment imposed to the welded joint. In this work, those properties were studied on electric arc welded joints of steel plates which have undergone three different post treatments. The three treatments are: (a) without post treatment, (b) heated in the furnace at 650° C for half an hour followed by furnace cooling and (c) covering the weld with asbest immediately after the last pass of welding process. Results of the study shows that covering the weld with asbests produces better mechanical properties than that without treatment, eventhough it is still inferior compared to the one which has been heated in the furnace. Due to the incomplexity and uncostly of the asbest-covered post treatment, it is necessary to study further the development of this treatment process for practical use
Locally Linearized Solution of Lifting Transonic Flow by Method of Parametric Differentiation
Get PDFThe governing equation of transonic small disturbance flow present a non-linear partial differential equation which is difficult to solve. The method of parametric differentiation reduces the non-linear partial differential equation of transonic flow into an ordinary differential equation with variable coefficient, which is generally much simple to solve. Further simplification is introduced, as also done in the method of local linearization, by assuming (1-M12) to vary sufficiently slowly, so that in some part of the analysis its derivatives with respect to x can be disregarded. Based upon these methods, the lifting transonic flow was analyzed. For the subsonic and supersonic parts, closed form solutions were obtained. For the case M1 ≈ 1, the method yields an integral equation, which can be solved by an iterative scheme starting from the non-lifting solution.
Effects of Chemical upon Electron Spin Resonance (ESR) Signals in Lettuce Seeds
No full textESR spectrometric study of chemically treated lettuce seeds has been carried out. Solutions of HgCl2, Na2S, KOH, KCN, KBr, KF, KIO3, KIO4, KCl, KI, and K2S, as well as water and petroleum ether have been used. Germination power and respiratory activity of the same seeds have also been investigated. Boiled seeds and gamma irradiated seeds have also been studied. KI was found to be the most effective agent. Independence upon cation and pH was found. The effect of KI and KCN was found to be reversible. No correlation between respiratory activity and the number of free radicals seems to exist. Seed coat is affected first and later on the embryo is also induced by the penetrating solution.
Tindjauan atas Masalah Hubungan Kerdja Praktis dan Pendidikan Kesardjanaan pada Bagian Mesin Institut Teknologi Bandung
Get PDFTulisan ini dibuat bersandarkan dasar fikiran jang dianut pada Bagian Mesin I.T.B. dalam mentugaskan para mahasiswanja mendjalankan kerdja praktis diberbagai perusahaan industry Indonesia. Kerdja praktis ini adalah dalam rangka pengisiskan para tjalon sardjana teknik mesin jang dinjatakan dalam rentjana peladjarannja. Bahan2 dikumpulkan berdasarkan pertjakapan2 dengan berbagai pihak dalam soal ini selama djangka waktu penulis mendjadi pengurus kerdja praktis pada Bagian Mesin tersebut. Bahan2 pembahasan akan dibagi kedalam golongan2 tindjauan berikut :* Hubungan kerdja praktis dengan pendidikan mahasiswa* Kerdja praktis sebagai penghubung I.T.B. dengan dunia perusahaan.* Kerdja praktis sebagai djalan bagi dunia industri untuk mengenal mahasiswa2 I.T.B. This article reviews the significance of the practical engineering work experience given by the various industries and workshops in Indonesia to the students of Bandung Institute of Technology, especially related to the mechanical engineering education. This review looks upon the problem utilizing the interest of the parties involved as the bases, namely:the interest of the education of the mechanical engineer to bethe interest of Bandung Institute of Technology as an institute of higher engineering learningthe interest of industrial enterprises.It is endeavored to express the viewpoints as clearly as possible in agreement with the many statements and opinions conceived by the author during many discussion with various parties about this practical engineering work experience of the mechanical engineering students of Bandung Institute of Technology. The parts of this article concerning these statements and opinions are presented based on memory, and therefore this article is far from being all inclusive. The author is of the opinion that the most important aspects are sufficiently covered in this short article
On the Nearest Real Singularities of a Single Loop Feynman Diagram
No full textIchtisar. Disini dibahas sarat-sarat untuk singularitas riel terdekat dari amplitude proses2 jang ditundjukkan oleh suatu diagram Feynman dengan satu lingkaran tertutup jang umumnja menjatakan produksi dari partikel2. Telah ditundjukkan bahwa sarat Landau dan positipnja parameter Feynman jang bersangkutan tidak tjukup. Sarat selandjutnja jang masih harus dipenuhi ternjata merupakan perluasan dari sarat Karplus, Sommerfield dan Wichmann jang diketemukan untuk "fungsi tiga titik". Selandjutnya akibat sarat tambahan ini dibahas, dimana ditundjukkan pula hubungannja dengan "dugaan" (conjecture) dari Nambu dan Blankenbeckler jang ternjata umumnja tak benar. Pembahasan ini djuga dapat dipergunakan pada diagram Feynman jang sembarang. Abstract. The nearest singularities of production amplitude corresponding to a single loop Feynman diagram is discussed. It is shown that Landau condition and the positiveness of the Feynman parameter is not sufficient for the part of Landau curve to be the nearest real singularity. The additional condition is the generalized Karplus, Sommerfield and Wichmann condition, originally found in the 3-point function. The consequences of this additional condition is discussed and related to Blanken-beckler-Nambu conjecture. The discussion is also applicable to an arbitrary Feynman diagram
Preparation of Monomeric 2,2-Dymethil-1,3-PropyleneDimethylmalonate; Potential Example of Conformational Isomerism and An Example of the Use of Molecular Models in Research Studies
Get PDFDengan penggunaan model2 molekul dapat dilihat kemungkinan adanja suatu isomeri jang stabil dalam senjawa lingkar berinti delapan jalah monomer 2,2 "“dimetilpropilen dimetilmalonat (1).Senjawa ini dibuat dengan djalan reaksi pertukaran ester antara 2,2-dimetil-1,3-propandiol dan etil dimetilmalonat, dengan dibutilstanni dibutoxida sebagai katalisator.Suatu hasil jang lumajan dapat diperoleh dengan teknik destilasi bertingkat jang lambat sekali dari hasil tjampuran reaksi.Hasil tersebut telah diselidiki dan terbukti adalah senjawa lingkar berinti delapan jang diharapkan, jalah suatu matjam bentuk jang biasanja sukar sekali dibuat.Kenjataan telah diperoleh dengan penggunaan chromatografi gas bahwa isomer2 konformasi dari I tidak stabil pada 150°C.Belum didapat keterangan2 lebih landjut mengenai kestabilan isomer2 konformasi pada suhu kamar
Oscillation Theorems for Second Order Delay Equations
No full textAbstract. Recently, oscillation criteria for certain second order delay differential equations have been substantially studied by [2], [3], [5], and others. In this paper, we generalize and extend some of their results to a more general delay differential equation of the type (r(t)y'(t))' + F (t,y(t),y(g(t))) = 0t ≥ α >
The Second Hankel Determinant Problem for a Class of Bi-Univalent Functions
Get PDFHankel matrices are related to a wide range of disparate determinant computations and algorithms and some very attractive computational properties are allocated to them. Also, the Hankel determinants are crucial factors in the research of singularities and power series with integral coefficients. It is specified that the Fekete-Szegö functional and the second Hankel determinant are equivalent to H1(2) and H2(2), respectively. In this study, the upper bounds were obtained for the second Hankel determinant of the subclass of bi-univalent functions, which is defined by subordination. It is worth noticing that the bounds rendered in the present paper generalize and modify some previous results.