Coupled-resonator optical waveguides: Q-factor and disorder influence

Coupled resonator optical waveguides (CROW) can significantly reduce light propagation pulse velocity due to pronounced dispersion properties. A number of interesting applications have been proposed to benefit from such slow-light propagation. Unfortunately, the inevitable presence of disorder, imperfections, and a finite Q value may heavily affect the otherwise attractive properties of CROWs. We show how finite a Q factor limits the maximum attainable group delay time; the group index is limited by Q, but equally important the feasible device length is itself also limited by damping resulting from a finite Q. Adding the additional effects of disorder to this picture, limitations become even more severe due to destructive interference phenomena, eventually in the form of Anderson localization. Simple analytical considerations demonstrate that the maximum attainable delay time in CROWs is limited by the intrinsic photon lifetime of a single resonator.Comment: Accepted for Opt. Quant. Electro

Energy expenditure in female workers in a textile factory

Autori su ispitivali energetske rashode radnica na tri radna mjesta, i to: šivanje električnim strojem, krojenje električnom pilom i rad na tkalačkom stroju za izradu vrpce. Ispitivanja su vršena standardnim metodama, određivanjem energetskih ekvivalenata za pojedine specifične radnje, izradom vremenskih tablica i preračunavanjem utrošenih kalorija po pojedinim radnim satima. Utrošeno radno vrijeme podijeljeno je na djelatnosti A, B i C. A = rad, osnovni za radno mjesto, B = priprema za izvršavanje osnovnog rada i C = odmor spontani i službeni. Energetska rashodi radnica u tekstilnoj industriji pokazuju velike razlike (do 500 kal.) po pojedinim radnim mjestima. Taj podatak omogućava da se i u ovakvim pogonima lake industrije izvrši diferencijacija radnih mjesta po njihovoj energetskoj opterećenosti. Osim toga ističu potrebu da se ispita mogućnost poboljšanja samog rada, kako bi se uz manji energetski utrošak mogao postići isti radni efekt.The authors have studied the problem of energy expenditure in female workers in a textile factory, by using standard methods. Data evaluated so far show that there is a great difference in energy expenditure for different works in this factory. lt is possible to differentiate the heaviness of work done in this industry, and it is necessary to investigate what should be done to reduce the energy expenditure to a lower level

Energy expenditure in textile workers

Određivani su energetski ekvivalenti za pojedine aktivnosti u tekstilnoj industriji. Ispitivanje je izvršeno kod 17 radnika i radnika poduzeća »Nada Dimić« u Zagrebu. Ukupno je ispitano 80 uzoraka izdahnutog zraka za devet aktivnosti specifičnih za takvo poduzeće. Analiza izdahnutog zraka vršena je metodom po Scholanderu. Dobiveni energetski ekvivalenti pokazuju da je raspon kalorija koje se troše za pojedine radnje dosta velik, pa da u prosjeku varira od 1,56 do 5,63 kal/min, ali se većina radova nalazi na donjoj granici rashoda.The examination of energy expenditure requirement was carried out in a textile factory in Zagreb. 17 workers, women and men, were examined by a Franz-Müller respirometer. Expired air samples were taken and analysed after Scholander. The results shown in calories per minute include values for basal metabolism. The energy expenditure was high only in few cases; in all others the values were very low, corresponding to the values obtained by other authors

Physical effort in surface miners

U velikom rudniku željezne rude izvršena su ispitivanja energetske potrošnje rudara na vanjskom kopu. Kod toga su obuhvaćeni radnici na 19 različitih radnih mjesta, među ostalima: kopači, vrtači, obarači rude, površinski kopači, bušači, sipači rude. utovarivači i istovarivači rude, bageristi. Energetska potrošnja ispitivana je standardnim metodama tako da se primijenila kronometraža radnog mjesta i određivanje energetske potrošnje za specifične radne operacije. Energetska potrošnja određivala se metodom indirektne kalorimetrije pomoću respirometra po Mulleru; za uzimanje uzoraka izdahnutog zraka, a analiza kisika i ugljičnog dioksida rađena je metodom po Scholenderu. Energetska potrošnja za neke radove pokazuje visoke vrijednosti kao na primjer: kopanje u rovu 8,4 Kal/min, rad na utovarivanju rude i jalovine 7,02 Kal/min, drobljenje rude batom 7,6 Kal/min, rad sa šipkom na otvoru sipke 8,2 Kal/min i izbacivanje rude iz vagona lopatom 9,7 Kal/min. Analogno visokoj energetskoj potrošnji za pojedine aktivnosti i ukupne kalorije na nekim mjestima pokazuju visoke vrijednosti pa se kreću po pojedinim zanimanjima u rasponu od 1277 do 3162 kalorija. Može se smatrati da u rudarskim radovima na vanjskom kopu postoje radna mjesta koja iziskuju velike fizičke napore.A study of energy expenditure was carried out in a large iron ore mine. Twenty different work places were analysed. Energy expenditure was determined by standard methods, including the chronometry of work places and the determination of energy equivalents for specific operations by indirect calorimetry using the Müller spirometer for the sampling of expired air. The Scholender method was used for the analysis of oxide and carbon dioxide. Some energy equivalents proved very high, e. g. digging 8,4 cal/min, loading 7,02 cal/min, crushing 7,6 cal/min, unloading 9,7 cal/min. Like energy equivalents, the work calories in some places were high too, ranging from 1277 to 3162 calories; the total daily energy expenditure ranged from 3157 to 4956 calories. It is concluded that in surface mining there are work places which require heavy physical effort

Light induced multiphase chemistry of gas-phase ozone on aqueous pyruvic and oxalic acids

International audienc