6,530 research outputs found
Counting interesting elections
We provide an elementary proof of a formula for the number of northeast
lattice paths that lie in a certain region of the plane. Equivalently, this
formula counts the lattice points inside the Pitman--Stanley polytope of an
n-tuple.Comment: 7 pages, 1 figure; published versio
Liquid-core low-refractive-index-contrast Bragg fiber sensor
We propose and experimentally demonstrate a low-refractive-index-contrast
hollow-core Bragg fiber sensor for liquid analyte refractive index detection.
The sensor operates using a resonant sensing principle- when the refractive
index of a liquid analyte in the fiber core changes, the resonant confinement
of the fiber guided mode will also change, leading to both the spectral shifts
and intensity changes in fiber transmission. As a demonstration, we
characterize the Bragg fiber sensor using a set of NaCl solutions with
different concentrations. Strong spectral shifts are obtained with the sensor
experimental sensitivity found to be ~1400nm/RIU (refractive index unit).
Besides, using theoretical modeling we show that low-refractive-index-contrast
Bragg fibers are more suitable for liquid-analyte sensing applications than
their high-refractive-index-contrast counterparts.Comment: 3 pages, 4 figure
Long, paired A'A/Pahoehoe flows of Mauna Loa: Volcanological significance and insights they provide into volcano plumbing systems
The long lava flows of Mauna Loa, Hawaii have been cited as Earth's closed analogs to the large Martian flows. It is therefore important to understand the flow mechanics and characteristics of the Mauna Loa flows and to make use of these in an attempt to gain insights into Martian eruptive processes. Two fundamentally different kinds of long lava flows can be distinguished on Hawaiian volcanoes as in Martian flows. The two kinds may have identical initial viscosities, chemical compositions, flow lengths, and flow volumes, but their flow mechanisms and thermal energy budgets are radically different. One travels a distance set by the discharge rate as envisaged by Walker and Wadge, and the other travels a distance set mainly by the eruption duration and ground slope. In the Mauna Loa lavas, yield strength becomes an important flow morphology control only in the distal part of a'a lavas. The occurrence of paired flows on Mauna Loa yields insights into the internal plumbing systems of the volcano, and it is significant that all of the volume of the a'a flow must be stored in a magma chamber before eruption, while none of the volume of the pahoehoe needs to be so stored. Differentiation between the two kinds of flows on images of Martian volcanoes is possible and hence an improved understanding of these huge structures is acquired
Effect of Pressure on the Activity Coefficients of Au and Other Siderophile Elements in Liquid Fe-Si Alloys
Light elements can alloy into the iron cores of terrestrial planetary bodies. It is estimated that the Earths core contains ~10% of a light element, most likely a combination of S, C, Si, and O with Si probably being the most abundant. Si dissolved into Fe metal liquids can have a significant influence on the activity coefficients of siderophile elements, and thus the partitioning behavior of those elements between the core and mantle. Many of these elements have been investigated extensively at ambient pressure, and studies up to 1 GPa are becoming more common, but few have been studied at pressures above this. The formation of the Earths core has been estimated to have formed at pressures between 40-60 GPa, so investigating the effect pressure has on Sis influence on siderophile element partitioning is important for modeling core formation in the Earth and smaller planets. Pressure is well known to influence volumetric properties of metallic and silicate liquids, and oxygen fugacity (e.g., [10,11]), but less is known about its effect on activity coefficients (e.g., [12]). Some activity coefficients depend strongly upon the Si content of Fe liquids, and the concentration of siderophile elements such as P, Sb, and As in the terrestrial mantle is easily influenced by dissolved Si in the core. Thus, isolating the effect of pressure on activity coefficients in general is critical in quantitative analysis of core formation models. In this work, we investigate the effect variable Si content has on the partitioning of Au between Fe metal and silicate melt at 10 GPa and 2373 K, with the intention of comparing the behavior to that already investigated at lower pressures. In addition, P, V, Mn, Ga, Zn, Cd, Sn, W, Pb, and Nb were also measured and could thus be included in the assessment of potential pressure effects
Final design specification for EOD-LARSYS/data transformation processor modification
There are no author-identified significant results in this report
The use of TIMS for mapping different pahoehoe surfaces: Mauna Iki, Kilauea
S-type and p-type pahoehoe record different mechanisms and vigors of activity within an active flow field. There is some controversy about what these mechanisms are exactly, and this study was undertaken with the idea that an accurate map of the two surfaces within a pahoehoe flow field could be helpful in solving the problem. Thermal Infrared Multispectral Scanner (TIMS) allows discrimination between s-type and p-type pahoehoe, and this ability was used to map the two surface types on the Mauna Iki satellite shield (southwest rift zone, Kilauea Volcano). TIMS was previously used to discriminate a'a from pahoehoe as well as to determine relative age relationships of different flows. Although inter-flow variation was minor in the data published by these authors, a second goal presented is to understand such variations to better constrain intra-flow differences used for age dating
A feasibility study of signal processing to improve antenna gain Final report
Feasibility of signal processor with phase isolator for adaptive antenna arra
Prevalence of working smoke alarms in local authority inner city housing: randomised controlled trial
Objectives To identify which type of smoke alarm is most likely to remain working in local authority inner city housing, and to identify an alarm tolerated in households with smokers. Design Randomised controlled trial. Setting Two local authority housing estates in inner London. Participants 2145 households. Intervention Installation of one of five types of smoke alarm (ionisation sensor with a zinc battery; ionisation sensor with a zinc battery and pause button; ionisation sensor with a lithium battery and pause button; optical sensor with a lithium battery; or optical sensor with a zinc battery). Main outcome measure Percentage of homes with any working alarm and percentage in which the alarm installed for this study was working after 15 months. Results 54.4% (1166/2145) of all households and 45.9% (465/1012) of households occupied by smokers had a working smoke alarm. Ionisation sensor, lithium battery, and there being a smoker in the household were independently associated with whether an alarm was working (adjusted odds ratios 2.24 (95% confidence interval 1.75 to 2.87), 2.20 (1.77 to 2.75), and 0.62 (0.52 to 0.74)). The most common reasons for non-function were missing battery (19%), missing alarm (17%), and battery disconnected (4%). Conclusions Nearly half of the alarms installed were not working when tested 15 months later. Type of alarm and power source are important determinants of whether a household had a working alarm
Marketing of Financial Services in the ECOWAS Sub-Region by Nigerian Banks: A Test Case for the Globalization of Nigerian Banking Industry
In the light of the increasing importance of segmentation
in the marketing of financial services, this paper argues
that Nigerian banking industry can enter the global
financial market with a strategy that incorporates both
segmentation and globalisation. To enable marketing of
financial services succeed in an era of globalisation, this
paper also suggests that the entire world can first be
segmented into regions which now form the plank for
globalisation. This, it says, because market segmentation
has been a fertile ground for financial services marketing
for many years. The adoption of segmentation strategies
within the financial services industry is a signs of the
globalization of marketing. Thus, the Nigerian banking
industry can make the ECOWAS sub-region its primary
segment in its bid to globalize its marketing operations in
the area of financial service
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