Universal condition for critical percolation thresholds of kagome-like lattices

Lattices that can be represented in a kagome-like form are shown to satisfy a universal percolation criticality condition, expressed as a relation between P_3, the probability that all three vertices in the triangle connect, and P_0, the probability that none connect. A linear approximation for P_3(P_0) is derived and appears to provide a rigorous upper bound for critical thresholds. A numerically determined relation for P_3(P_0) gives thresholds for the kagome, site-bond honeycomb, (3-12^2), and "stack-of-triangle" lattices that compare favorably with numerical results.Comment: Several new figures and small change

Towards a historical ecology of intertidal foraging in the Mafia Archipelago: archaeomalacology and implications for marine resource management

Understanding the timing and nature of human influence on coastal and island ecosystems is becoming a central concern in archaeological research, particularly when investigated within a historical ecology framework. Unfortunately, the coast and islands of eastern Africa have not figured significantly within this growing body of literature, but are important given their historically contingent environmental, social, and political contexts, as well as the considerable threats now posed to marine ecosystems. Here, we begin developing a longer-term understanding of past marine resource use in the Mafia Archipelago (eastern Africa), an area of high ecological importance containing the Mafia Island Marine Park. Focusing on the comparatively less researched marine invertebrates provides a means for initiating discussion on potential past marine ecosystem structure, human foraging and environmental shifts, and the implications for contemporary marine resource management. The available evidence suggests that human-environment interactions over the last 2000 years were complex and dynamic; however, these data raise more questions than answers regarding the specific drivers of changes observed in the archaeomalacological record. This is encouraging as a baseline investigation and emphasizes the need for further engagement with historical ecology by a range of cognate disciplines to enhance our understanding of these complex issues

Penilaian Kinerja di Divisi Pelayanan Terminal untuk Mengukur Keberhasilan Organisasi di PT. Pelabuhan Indonesia I Belawan

PT Pelabuhan Indonesia I merupakan Perusahaan yang bergerak dibidang penyelenggaraan dan pengusahaan jasa kepelabuhanan bertujuan mengoptimalisasi pemanfaatan sumber daya yang dimiliki Perusahaan untuk menghasilkan barang atau jasa yang bermutu tinggi dan berdaya saing kuat maka kebutuhan akan tingkat kinerja yang tinggi dari setiap karyawan merupakan hal yang mutlak bagi PT. Pelabuhan Indonesia I. Berdasarkan hasil penilaian persentase kompetensi dan produktivitas yang telah ada, persentase realisasi yang dicapai lebih kecil dari angka target yang ditetapkan oleh Perusahaan. kesenjangan ini mengindikasikan bahwa kinerja karyawan belum maksimal dan perlu adanya penilaian kinerja lebih lanjut. Penilaian kinerja merupakan suatu evaluasi hasil kerja dari seorang karyawan secara sistematis yang berhubungan dengan jabatannya dan potensi yang dimilikinya untuk dikembangkan. Penilaian kinerja ini diharapkan dapat menjadi umpan Balik bagi karyawan tersebut tentang prestasi kerjanya selama ini dan mengembangkan kemampuannya lebih lanjut. Penilaian kinerja bertujuan untuk akan meningkatkan prestasi organisasi. Penelitian ini menggunakan kuesioner, software SPSS 17.0 dan Matlab sebagai instrumen penelitian. Hasil perhitungan menunjukkan bahwa pada level top manajemen, Manajer pelayanan terminal memiliki penilaian kinerja tertinggi dengan nilai eigen 2.1903. Pada level middle manajemen, Supervisor Pelayanan Operasi Senior memiliki penilaian kinerja tertinggi dengan nilai eigen 2.7424. Pada level lower manajemen, penilaian kinerja tertinggi adalah Pelaksana Perencanaan & Pengendalian Operasi Senior dengan nilai eigen 2.6141. Jabatan Asisten Manajer Pelayanan Operasi dan Jabatan Pelaksana Pelayanan Operasi Senior merupakan jabatan yang memiliki penilaian kinerja yang sangat rendah sehingga memerlukan evaluasi lebih lanjut. Hal ini dapat dilihat dari nilai eigen kedua jabatan yang bernilai negatif, masing-masing yaitu -0.0005 dan -0.000

A Dimension-Adaptive Multi-Index Monte Carlo Method Applied to a Model of a Heat Exchanger

We present an adaptive version of the Multi-Index Monte Carlo method, introduced by Haji-Ali, Nobile and Tempone (2016), for simulating PDEs with coefficients that are random fields. A classical technique for sampling from these random fields is the Karhunen-Lo\`eve expansion. Our adaptive algorithm is based on the adaptive algorithm used in sparse grid cubature as introduced by Gerstner and Griebel (2003), and automatically chooses the number of terms needed in this expansion, as well as the required spatial discretizations of the PDE model. We apply the method to a simplified model of a heat exchanger with random insulator material, where the stochastic characteristics are modeled as a lognormal random field, and we show consistent computational savings

An Improved Slant Path Attenuation Prediction Method in Tropical Climates

An improved method for predicting slant path attenuation in tropical climates is presented in this paper. The proposed approach is based on rain intensity data R_0.01 (mm/h) from 37 tropical and equatorial stations; and is validated by using the measurement data from a few localities in tropical climates. The new method seems to accurately predict the slant path attenuation in tropical localities, and the comparative tests seem to show significant improvement in terms of the RMS of the relative error variable compared to the RMS obtained with the SAM, Crane, and ITU-R prediction models

Analysis of heat transfer and entropy generation for a thermally developing Brinkman–Brinkman forced convection problem in a rectangular duct with isoflux walls

Heat transfer and entropy generation analysis of the thermally developing forced convection in a porous-saturated duct of rectangular cross-section, with walls maintained at a constant and uniform heat flux, is investigated based on the Brinkman flow model. The classical Galerkin method is used to obtain the fully developed velocity distribution. To solve the thermal energy equation, with the effects of viscous dissipation being included, the Extended Weighted Residuals Method (EWRM) is applied. The local (three dimensional) temperature field is solved by utilizing the Green’s function solution based on the EWRM where symbolic algebra is being used for convenience in presentation. Following the computation of the temperature field, expressions are presented for the local Nusselt number and the bulk temperature as a function of the dimensionless longitudinal coordinate, the aspect ratio, the Darcy number, the viscosity ratio, and the Brinkman number. With the velocity and temperature field being determined, the Second Law (of Thermodynamics) aspect of the problem is also investigated. Approximate closed form solutions are also presented for two limiting cases of MDa values. It is observed that decreasing the aspect ratio and MDa values increases the entropy generation rate

Relationship between Single Walled Carbon Nanotubes Individual Dispersion Behavior and Properties of Electrospun Nanofibers

The dispersion stability behavior of single walled carbon nanotube (SWCNT) has important effects on morphological and mechanical properties of SWCNT/polymer composite nanofibers. The effects of SWCNTs incorporation on the morphological and structural developments and the relation between this develop-ments and mechanical properties of the polyacrylonitrile (PAN) nanofibers were demonstrated. The uni-form, stable dispersion and well oriented SWCNT within the PAN matrix were achieved through using polyvinylpyrrolidone (PVP) as dispersing agent. Our data indicate that with increasing the amount of SWCNT (from 0 to 2 wt %), the average nanofiber diameter was increased from 163±19 nm to 307±34 nm. The analysis of the mechanical properties of the composite nanofibers displays that they exhibit an im-provement in the tensile strength of ∼172% from 3.93±0.45 MPa to 10.74±1.03 MPa, and the elastic modu-lus was increased by ~885% from 61.39±15.58 GPa to 605.08±65.55 GPa, as compared to the pure electro-spun nanofibers. The optimal SWCNT concentration for electrospun nanofibers with better morphological and mechanical properties is ~2 wt %. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3516

Hyperbaric oxygen therapy for the treatment of radiation-induced macular ischemia

Shamim A Haji1,2, Ronald EP Frenkel1,2,31Eye Research Foundation, Stuart, FL, USA; 2East Florida Eye Institute, Stuart, FL, USA; 3Bascom Palmer Eye Institute, Miami, FL, USAPurpose: To report a case of radiation-induced macular ischemia where vision and macular perfusion improved after hyperbaric oxygen (HBO) therapy.Methods: A 62-year-old male patient developed radiation-induced macular ischemia after he was treated with radiation for brain glioma. The patient presented with best spectacle-corrected visual acuity (BSCVA) acuity of 20/400 in his right eye. Optical coherence tomography (OCT) showed central macular thickness of 468 μm. The patient received focal laser, intravitreal triamcinolone, and HBO therapy.Results: The patient’s vision improved from 20/400 to 20/100 after focal laser and intravitreal triamcinolone. His central macular thickness improved from 468 μm to 132 μm. After receiving HBO therapy, his VA improved to 20/50 and fluorescein angiography showed improvement in macular perfusion.Conclusion: HBO therapy improves macular perfusion in patients with radiation-induced macular ischemia.Keywords: macular ischemia, visual acuity, hyperbaric oxygen therapy, macular perfusio

Penilaian Penawaran Terendah Yang Responsif Pada Pengadaan Barang Dan Jasa Pemerintah Berbasis Teknologi Komputasi

Salah satu tahapan yang paling penting dalam proses pemilihan penyedia barang/jasa pemerintah adalah penetapan calon pemenang lelang. Perpres Nomor 54 Tahun 2010 (dan Perubahannya) menyatakan bahwa ULP mengusulkan penawar terendah yang responsif sebagai calon pemenang. Tidak ada definisi dan rumusan yang jelas tentang “penawaran terendah yang responsif”, sehingga ketentuan tersebut memiliki peluang untuk diinterpretasikan secara berbeda menurut kepentingan pihak pengguna dan penyedia barang/jasa. Akibatnya, penetapan calon pemenang lelang cenderung bersifat subjektif, tidak baku, berlarut-larut, rentan terhadap praktik KKN, berpotensi menimbulkan kebocoran keuangan negara, dan berdampak buruk terhadap kinerja proyek-proyek pemerintah. Penelitian ini bertujuan untuk memformulasikan dan mendesain suatu metode dan sistem yang dapat digunakan untuk menilai dan menetapkan harga penawaran terendah yang responsif secara ilmiah, mudah dioperasikan, memberikan hasil akurat dan seketika, sehingga dapat membantu Kelompok Kerja ULP pada seluruh Kementerian, Lembaga, SKPD, dan institusi lainnya di seluruh Indonesia dalam mengatasi berbagai persoalan empirik sehubungan dengan subjektifitas dan ketidakpastian dalam penetapan pemenang lelang. Rasio antara penawaran harga kontraktor dan pemenang lelang terhadap HPS diklasifikasi menurut interval kelas tertentu. Hasil penelitian ini menemukan bahwa penawaran harga pemenang lelang berada pada interval nilai 73% s/d 98% terhadap nilai HPS dan menghasilkan koefisien responsif c = 0,01161. Nilai ini menunjukkan bahwa keputusan penetapan pemenang lelang dilakukan secara subjektif, tidak memiliki kepastian, tidak baku, dan tidak konsisten. Harga penawaran yang responsif diformulasikan dengan . Pemenang lelang ditetapkan yang memenuhi nilai terendah (Ci,min) pada kelas responsi