5,790 research outputs found

    Fabrication of free-standing ordered fluorescent polymer nanofibres by electrospinning

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    The authors are grateful to the Engineering and Physical Sciences Research Council for financial support.We demonstrate a static fabrication approach to make free-standing ordered arrays of fluorescent nanofibres through control of the transverse electrospinning field. The alignment and the density of the nanofibre arrays are optimised by careful design of both the source and collector electrode geometries which can control the transverse electric field over the full path of the jet. In doing so, we fabricate suspended fluorescent nanofibres with an aspect ratio of 10(4), and with a substantially increased density and order parameter (by a factor of similar to 10 compared to random deposition). Electrostatic modelling suggests that the field distribution of the component is the main contribution to the ordering between the plates. This method offers increased efficiency for the creation of ordered fibres collected over a small area and the characterisation of their photoluminescent properties.Publisher PDFPeer reviewe

    The Role of the Family in Immigrants' Labor-Market Activity: Evidence from the United States

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    We use Census of Population microdata for 1980 and 1990 to examine the labor supply and wages of immigrant husbands and wives in the United States in a family context. Earlier research by Baker and Benjamin (1997) posits a family investment model in which, upon arrival, immigrant husbands invest in their human capital while immigrant wives work to provide the family with liquidity during this period. Consistent with this model, they find for Canada that immigrant wives work longer hours upon arrival than comparable natives, but, with time in Canada, they are eventually overtaken by native wives. In contrast, we find that, among immigrants to the United States, both husbands and wives work and earn less than comparable natives upon arrival, with similar shortfalls for men and women. Further, both immigrant husbands and wives have similar, positive assimilation profiles in wages and labor supply and eventually overtake both the wages and the labor supply of comparable natives.

    On the transcendence degree of the differential field generated by Siegel modular forms

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    It is a classical fact that the elliptic modular functions satisfies an algebraic differential equation of order 3, and none of lower order. We show how this generalizes to Siegel modular functions of arbitrary degree. The key idea is that the partial differential equations they satisfy are governed by Gauss--Manin connections, whose monodromy groups are well-known. Modular theta functions provide a concrete interpretation of our result, and we study their differential properties in detail in the case of degree 2.Comment: 21 pages, AmSTeX, uses picture.sty for 1 LaTeX picture; submitted for publicatio

    Using Pilot Systems to Execute Many Task Workloads on Supercomputers

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    High performance computing systems have historically been designed to support applications comprised of mostly monolithic, single-job workloads. Pilot systems decouple workload specification, resource selection, and task execution via job placeholders and late-binding. Pilot systems help to satisfy the resource requirements of workloads comprised of multiple tasks. RADICAL-Pilot (RP) is a modular and extensible Python-based pilot system. In this paper we describe RP's design, architecture and implementation, and characterize its performance. RP is capable of spawning more than 100 tasks/second and supports the steady-state execution of up to 16K concurrent tasks. RP can be used stand-alone, as well as integrated with other application-level tools as a runtime system

    Pengaturan Level Ketinggian Air Menggunakan Kontrol PID

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    This paper describes about the application of control system on liquid level control system. The control method used in this system is proportional integral derivative (PID) controller. All control processes and data aquisition is run by using a personal computer (PC). Experiment was done by controlling liquid level in level range 0 - 30 cm. Experiment was also done by using various PID control parameter in which the input signal is step function. Experiment results show that the parameter of liquid level control system are Kp = 1 - 10, Ki = 0,1 - 5 and Kd = 0,1 - 1

    The Analysis of Nitrate and Phosphate Concentration with Diatom Abundance in Air Hitam Strait of Meranti Islands Regency of Riau Province

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    The research was conducted in July 2014 in Air Hitam Strait of Meranti Islands Regency of Riau Province. This research aims to analyze the concentration of nitrate and phosphate and the relationship with diatom abundance. The samples were taken from 4 stations and each station was divided into 3 sampling points. The result showed the average value of nitrate and phosphate concentration were 0.122 mg/L and 0.021 mg/L. This research identified 12 genus of diatom. The highest abundance of diatom was found in Station 3 around of the floating cage locations (162.96 Ind/L) and the lowest was at Station 4 around harbor (111.11 Ind/L). The result of the simple linear regression of nitrate and phosphate concentration showed a positive relation with diatom abundance, that means if the concentration of nitrate and phosphate are raising the diatom abundance was also increasing

    Pengaruh Penambahan Minyak Atsiri Kunyit Putih (Kaempferia Rotunda) Pada Edible Film Pati Tapioka Terhadap Aktivitas Antimikroba Dan Sensoris

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    Tujuan dari penelitian ini untuk mengetahui aktivitas antioksidan minyak atsiri kunyit putih serta pengaruh penambahan minyak kunyit putih terhadap aktivitas antimikroba dan karakteristik sensori edible film tapioka. Aktivitas antioksidan minyak atsiri kunyit putih diuji menggunakan metode DPPH. Pengujian aktivitas antimikroba dilakukan terhadap bakteri Pseudomonas putida FNCC 0070 dan Pseudomonas fluorescens FNCC 0071 sedangkan karakteristik sensori diuji dengan metode perbandingan jamak dan metode hedonik. Aktivitas antioksidan minyak atsiri kunyit putih yang dihasilkan sebesar 1,281% DPPH/mg. Aktivitas antimikroba edible film dengan penambahan 0.1% minyak atsiri kunyit putih mampu menghambat Pseudomonas putida FNCC 0070 sebesar 29,44 mm dan Pseudomonas fluorescens FNCC 0071sebesar 29,99mm. Berdasarkan uji perbandingan jamak diketahui bahwa edible film dengan penambahan 1% minyak atsiri kunyit putih mempunyai karakteristik yang masih mendekati edible film tanpa penambahan minyak atsiri dan juga diterima panelis
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