9,522 research outputs found
The Suppression of Radiation Reaction and Laser Field Depletion in Laser-Electron beam interaction
The effects of radiation reaction (RR) have been studied extensively by using
the ultraintense laser interacts with the counter-propagating relativistic
electron. At the laser intensity at the order of W/cm, the
effects of RR are significant in a few laser period for a relativistic
electron. However, the laser at such intensity is tightly focused and the laser
energy is usually assumed to be fixed. Then, the signal of RR and energy
conservation cannot be guaranteed. To assess the effects of RR in a tightly
focused laser pulse and the evolution of the laser energy, we simulate this
interaction with a beam of electrons by means of Particle-in-Cell (PIC)
method. We observed that the effects of RR are suppressed due to the
ponderomotive force and accompanied by a non-negligible amount of laser field
energy reduction. This is due to the ponderomotive force that prevents the
electrons from approaching the center of the laser pulse and leads to the
interaction at weaker field region. At the same time, the laser energy is
absorbed through ponderomotive acceleration. Thus, the kinetic energy of the
electron beam has to be carefully selected such that the effects of RR become
obvious.Comment: 6 pages, 3 figure
Techno-economics Analysis of Biodiesel Production From Palm, Jatropha Curcas and Calophyllum Inophyllum as Biofuel
Transportation sector has a dominant role in global fuel consumption andgreenhouse gas emissions consequently. Biodiesel is a renewable energy that has great potential to serve as an alternative fuel to fossil diesel in diesel engine. Besides the technical barriers, there are several nontechnical limiting factors, which impede the development of biodiesel. Therefore, this study is focused on biodiesel production and techno-economic comparison among palm, jatropha curcas and calophyllum inophyllum biodiesel as transportation fuel. Moreover, the present study attempts to find out the impact of biodiesel implementation towards the energy scenario, environmental and economy. The largest economic factor for biodiesel production is feedstock cost. Furthermore, replacing 5% of diesel fuel with biodiesel fuel in road transport can reduce theCO2 emission up to 1200 ktons in year 2031. When the subsidy policy and tax exemption are implemented, biodiesel fuel is more competitive than fossil diesel at the current production costs. Therefore, this study serves as a guideline for further investigation on biodiesel production and other limitation factors before the wider utilization of biodiesel can be implemented
Airport revenue management: does airport size matter?
Airports today operate as business entities. Competition between airlines has revolutionized the way airports operate. There is an increasing preference for smaller airports. This has improved the economic and financial viability of small and medium airports from non-aeronautical revenue. An empirical study examines the relationship between airport size and airport profits. There is no statistically significant evidence from the results to suggest that small/medium airports are less profitable than major hub airports as the former reconfigure their activities in response to changing circumstances
Season of the year influences infection rates following total hip arthroplasty
To research the influence of season of the year on periprosthetic joint infections. METHODS We conducted a retrospective review of the entire Medicare files from 2005 to 2014. Seasons were classified as spring, summer, fall or winter. Regional variations were accounted for by dividing patients into four geographic regions as per the United States Census Bureau (Northeast, Midwest, West and South). Acute postoperative infection and deep periprosthetic infections within 90 d after surgery were tracked. RESULTS In all regions, winter had the highest incidence of periprosthetic infections (mean 0.98%, SD 0.1%) and was significantly higher than other seasons in the Midwest, South and West (P \u3c 0.05 for all) but not the Northeast (P = 0.358). Acute postoperative infection rates were more frequent in the summer and were significantly affected by season of the year in the West. CONCLUSION Season of the year is a risk factor for periprosthetic joint infection following total hip arthroplasty (THA). Understanding the influence of season on outcomes following THA is essential when risk-stratifying patients to optimize outcomes and reduce episode of care costs. © The Author(s) 2017
Improved fuzzy hashing technique for biometric template protection
Biometrics provides a new dimension of security to modern automated applications since each user will need to prove his identity when attempting an access. However, if a stored biometric template is compromised, then the conventional biometric recognition system becomes vulnerable to privacy invasion. This invasion is a permanent one because the biometric template is not replaceable. In this paper, we introduce an improved FuzzyHashing technique for biometric template protection purpose. We demonstrate our implementation in the context of fingerprint biometrics. The experimental results and the security analysis on FVC 2004 DB1 and DB2 fingerprint datasets suggest that the technique is highly feasible in practice
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