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We celebrate Certec’s 20th birthday . . . . . . by giving you a book of 20 important ideas filled with pictures and text. Each idea is expressed in a succinct heading that sums up what we have learned over the years. The ideas also act as a complement to all the reports, website cover pages, brochures, lectures and annual reports. There are 30,000 documents at www.certec.lth.se that provide the
A power-series expansion method for approximate analysis of the guided modes in a cylindrical, radially inhomogeneous dielectric waveguide is presented. The method is developed for a piece-wise polynominal permittivity profile. The solution of the scalar wave equation is constructed by a sequence of power-series expantions. Convergence is ensured and accuracy maintained by regulating the distance
In this paper, physical limitations on the directivity D and Q-factor Q are derived for antennas of arbitrary shape. The quotient D/Q is shown to be bounded from above by the antenna volume and certain shape coefficients in terms of the eigenvalues of the high-contrast polarizability dyadic. The theory is exemplified by numerical results for the half-wave antenna with astonishing agreement.
Robotar kan betraktas som ytterligare en i raden av tekniska innovationer inom äldreomsorgen, buren av förhoppningar om ökad effektivitet men med bibehållen livskvalitet i samband med ökade omsorgsbehov och möjligheten att bo kvar hemma. Diskursen är tidvis utopisk - löften om att hjälpa äldre människor att bli mer självförsörjande och självständiga med hjälp av robotar - och från ett mer dystopis
Decision outcomes and their lead times are critical in product management, as the market success of a product may strongly depend on the both the decisions themselves and their timing in relation to the market and competitors. This paper presents an investigation of one particular industrial case study data set by comparing upstream scoping decisions with downstream change decision. The results in
Bacteria have a remarkable ability to adapt to different environments. When bacteria encounter stress that causes macromolecular damage in the cell, leading to a suboptimal performance of cell metabolism, they can elicit an adaptive response. In this thesis Bacillus subtilis is used as the primary model organism to study bacterial adaptation to oxygen limitation, reactive nitrogen species and disu
Popular Abstract in Swedish Luften vi andas innehåller inte bara gaser som kväve och det syre vi behöver för att leva. Förutom de vanligaste gaserna i atmosfären finns det så kallade spårgaser, som visserligen har väldigt låg koncentration, men som har stor betydelse genom sina speciella kemiska och fysiska egenskaper. Koldioxid och ozon är exempel på sådana gaser. Förutom ozonets kraftiga oxideraThe air around us is full of aerosol particles which originate from a myriad of sources and which have vastly different chemical and physical properties. These particles span size ranges from 1 nm to 100 μm, equivalent to a factor 100 000 in diameter difference and a factor 10^15 in volume difference. They affect our health by depositing in our airways, worsening cardiovascular deceases, and they
