258,470 research outputs found
Laguerre geometry of hypersurfaces in R-n
No full textLaguerre geometry of surfaces in R-3 is given in the book of Blaschke [Vorlesungen uber Differentialgeometrie, Springer, Berlin Heidelberg New York (1929)], and has been studied by Musso and Nicolodi [Trans. Am. Math. soc. 348, 4321-4337 (1996); Abh. Math. Sem. Univ. Hamburg 69, 123-138 (1999); Int. J. Math. 11(7), 911-924 (2000)], Palmer [Remarks on a variation problem in Laguerre geometry. Rendiconti di Mathematica, Serie VII, Roma, vol. 19, pp. 281-293 (1999)] and other authors. In this paper we study Laguerre differential geometry of hypersurfaces in R-n. For any umbilical free hypersurface x:M -> R-n with non-zero principal curvatures we define a Laguerre invariant metric g on M and a Laguerre invariant self-adjoint operator S:TM -> TM, and show that {g,S} is a complete Laguerre invariant system for hypersurfaces in R-n with >= 4. We calculate the Euler-Lagrange equation for the Laguerre volume functional of Laguerre metric by using Laguerre invariants. Using the Euclidean space R-n, the semi-Euclidean space R-1(n) and the degenerate space R-0(n) we define three Laguerre space forms URn, UR1n and UR0n and define the Laguerre embeddings URn1 -> URn and UR0n -> URn, analogously to what happens in the Moebius geometry where we have Moebius space forms S-n, H-n and R-n (spaces of constant curvature) and conformal embeddings H-n -> S-n and R-n -> S-n[cf. Liu et al. in Tohoku Math. J. 53, 553-569 (2001) and Wang in Manuscr. Math. 96, 517-534 (1998)]. Using these Laguerre embeddings we can unify the Laguerre geometry of hypersurfaces in R-n, R-1(n) and R-0(n). As an example we show that minimal surfaces in R-1(3) or R-0(3) are Laguerre minimal in R-3.MathematicsSCI(E)0ARTICLE173-9512
An NMDA Receptor Mediated Hypothesis
No full text(Statement of Responsibility) by Patrick R. Klem(Thesis) Thesis (B.A.) -- New College of Florida, 2001(Electronic Access) RESTRICTED TO NCF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE(Bibliography) Includes bibliographical references.(Source of Description) This bibliographic record is available under the Creative Commons CC0 public domain dedication. The New College of Florida, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.(Local) Faculty Sponsor: Callahan, Charlen
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Pengaruh Kait Klem Selang Dengan Variasi Jarak Kait Terhadap Kuat Lentur Balok Bertulangan Bambu
Get PDFBahan material beton banyak digunakan dalam bidang konstruksi dikarenakan memiliki kelebihan. diantaranya kuat akan tekan yang tinggi dan mudah dalam perawatan. Namun, disisi lain juga memiliki. kekurangan yaitu kuat akan tarik yang lemah sehingga dalam pembuatan sering. dikombinasikan dengan tulangan. Tulangan bambu merupakan salah satu alternatif untuk mengurangi penggunaan tulangan baja. Meskipun tegangan tarik bambu bisa dibandingkan dengan baja, tetapi bambu. memiliki kuat lekat yang rendah dengan beton sehingga. beton bertulang bambu masih kurang efektif dalam menerima beban. Sehingga beton bertulang bambu dengan penambahan. pemasangan kait berupa klem selang diharapkan mampu menambah tegangan lekat pada beton. Pada penelitian ini, pembuatan benda uji berupa balok bertulang. bambu dengan kait klem selang berdimensi 18x25x160cm dan variasi jarak pemasangan kait klem selang adalah 12 dan 6 cm sebanyak 16 benda uji termasuk benda uji kontrol (tanpa kait). Besar kapasitas beban yang diterima oleh balok tanpa kait klem selang (A0) rata-rata sebesar 2783.09 kg. Sedangkan pada balok dengan kait klem selang dengan jarak 12 cm (A1) rata-rata sebesar 3213,74 kg dan jarak 6 cm (A2) rata-rata sebesar 3215.21 kg. Berdasarkan uji statistik dengan metode Two-Way ANNOVA. dan analisis regresi didapatkan adanya pengaruh yang signifikan dengan dipasangnya kait klem selang. terhadap kuat lentur balok bertulang bambu dan terdapat interaksi antara pemasanganjarak kait klem selang dengan rasio tulangan
Uji Cabut Tulangan Bambu Dengan Variasi Jarak Kait Dari Klem Selang
Get PDFBeton bertulang adalah material komposit yang sangat baikuntuk konstruksi bangunan.Tulangan yang digunakan umumnya adalah material baja sebagai penahan tegangan tarik. Salah satu pengganti tulangan baja adalah bambu karena pertumbuhan cepat di Indonesia dan memiliki kekuatan tarik yang tinggi. Tetapi bambu memiliki kelemahan yaitu tegangan lekat yang rendah maka perlu adanya upaya untuk mengatasi kelemahan tersebut salah satunya dengan menambahkan kait klem selang pada tulangan bambu. Dalam penelitian ini akan diteliti mengenai variasi jarak kait menggunakan klem selang. Benda uji pull outberukuran 15 cm x 30 cm x 40 cm, dengan variasi jarak klem selang 6 cm dan 12 cm sebanyak 18 buah.Hasil uji pull out ketika perpindahan 2,75 mm tegangan lekat pada jarak klem selang 12 cm dengan dimensi tulangan 1,5 x 1,5 cm sebesar 0,336 MPa. Dari hasil uji hipotesis dengan metode anova didapatkan bahwa belum ada pengaruh yang signifikan variasi jarak kait klem selang terhadap tegangan lekat tulangan bambu (F2 = 0,760 < F tabel = 3,885). Kata
Measuring Firms’ R&D Effects on Technical Progress: Japan in the 199
Get PDFOne of the important public policy issues in science and technology is to ascertain if and how firms' investments in research and development (R&D) contribute to technical progress at firm and industry levels. Griliches (1979) made a pioneering contribution to our understanding of economic growth by pointing out that accumulation of firms' investments in R&D and creation of knowledge will lead to technical progress. In this paper we present a method based on index number theory for estimating technical progress and then apply it for estimating technical progress for Japanese manufacturing firms in the 1990s. Estimated technical progress is then used to test the above Griliches hypothesisR&D; Japan; technical progress; economic growth
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
Get PDFBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Pembuatan Klem Pemegang Pipa Peralon dari Limbah Plastik Menggunakan Proses Compression Molding
Get PDFTujuan penelitian ini adalah menaikkan nilai tambah sampah plastik menjadi produk klem pemegang pipa paralon dengan proses compression molding di bengkel teknik mesin Polteknik negeri Semarang. Sampah plastik yang sering kita jumpai disekitar kita adalah jenis Polyethylene Terephthalate (PET) dari bekas kemasan air mineral dan Polypropylene (PP) dari bekas alat rumah tangga seperti ember, kursi dan lain-lainya, agar mengurangi beban lingkungan maka perlu di daur ulang menjadi produk klem pemegang pipa paralon dengan proses compression molding, dari hasil penelitian diperoleh kekuatan tegangan bengkok produk klem plastik penjepit paralon yaitu bahan plastik daur ulang PP menghasilkan kekuatan/tegangan bengkok sebesar σb=4,67 N/mm2, dan bahan plastik daur ulang PET menghasilkan kekuatan/tegangan bengkok sebesar σb=4,325 N/mm2
Experimental investigation into the effect of substrate clamping on the piezoelectric behaviour of thick-film PZT elements
No full textThis paper details an experimental investigation of the clamping effect associated with thick-film piezoelectric elements printed on a substrate. The clamping effect reduces the measured piezoelectric coefficient, d33, of the film. This reduction is due to the influence of the d31 component in the film when a deformation of the structure occurs, by either the direct or indirect piezoelectric effect. Theoretical analysis shows a reduction in the measured d33 of 62%, i.e. a standard bulk lead zirconate titanate (PZT)-5H sample with a manufacturer specified d33 of 593pC/N would fall to 227.8pC/N. To confirm this effect, the d33 coefficients of five thin bulk PZT-5H samples of 220µm thickness were measured before and after their attachment to a metallized 96% alumina substrate. The experimental results show a reduction in d33 of 74% from 529pC/N to 139pC/N. The theoretical analysis was then applied to existing University of Southampton thick-film devices. It is estimated that the measured d33 value of 131pC/N of the thick-film devices is the equivalent of an unconstrained d33 of 345pC/N
TEKNO KLEM: NEW DISPOSABLE DEVICE FOR PEDIATRIC CIRCUMCISION–A CASE REPORT
Get PDFObjective: This case report aimed to present the use of Tekno Klem, a novel disposable circumcision device. Unlike existing devices, Tekno Klem allows immediate clamp removal, potentially reducing the risk of postoperative complications. Case(s) Presentation: A 6-year-old boy presented to the Urology Outpatient Clinic with difficulty in retracting the foreskin of the penis. Physical examination revealed a non-retractable foreskin with a constrictive ring, classified as grade 3 phimosis. Elective dorsal slit surgery using Tekno Klem device was scheduled. The circumcision procedure using the Tekno Klem device began with measuring the glans size to ensure appropriate device selection. The appropriate Tekno Klem clamp size was selected from the available options: 12 mm, 14 mm, 16 mm, 18 mm, 22 mm, and 27 mm. The preputial skin was marked to define the excision area. The safety tube was then carefully positioned around the glans. Subsequently, the clamp frame was inserted. Once the desired positioning was confirmed, the screw cap was applied, locking the clamp securely in place through its serrated and threaded mechanism. The preputial skin was excised using thermal cautery. After clamp removal, N-butyl cyanoacrylate ointment was applied to protect the wound. The procedure lasted 15 minutes. Discussion: Postoperative pediatric penile perception scored 10, indicating improved penile appearance, while voiding satisfaction scored 5, reflecting favorable functional outcomes. No complications, including bleeding, hematoma, infection, glans injury, meatal stenosis, or delayed healing, were observed. The circumcision site healed properly with satisfactory cosmetic and functional results. Conclusion: Tekno Klem offers enhanced precision, safety, and ease of use over conventional devices, with the potential to reduce complications and optimize outcomes, particularly in settings prioritizing surgical accuracy and patient safety.
Keywords: Tekno Klem, circumcision, disposable, pediatric, clamp
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