scholarly journals On the absolute measurement of light: A proposal for an ultimate light standard

1911 ◽  
Vol 85 (578) ◽  
pp. 275-284 ◽  
Keyword(s):  
Colour Vision ◽  
Absolute Measurement ◽  
Mercury Vapour ◽  
Filament Lamp ◽  
First Case ◽  
Wide Range ◽  
Mercury Vapour Lamp ◽  
Relative Luminosity ◽  
Normal Colour ◽  
Metal Filament

The measurement of the intensity of a source of light is, it is well known, a somewhat unsatisfactory process. The eye cannot estimate light intensity; it can only tell when the illumination of two adjacent surfaces is equal. If, for example, we desire to measure the intensity of a metal filament lamp, we compare it with a Hefner lamp and say that the intensities are inversely as the squares of the distances from the photometer head, when equal illumination is obtained. In strictness, however, this method is applicable only when the colours of the two sources, or more accurately when the distribution of energy in the spectra of the two sources, is exactly the same; for the relative luminosity of the different colours of a spectrum varies with the intensity of that spectrum. Abney has two well-known curves illustratinghis. One, which represents the relative luminosity of the different colours of a spectrum at ordinary intensity, has a maximum in the orange; the other which is for a spectrum with the same distribution of energy, but with an intensity of less than 1/100 candle-foot, has its maximum in the green. If, therefore, we have an extremely long photometer bench, and an experimenter with normal colour vision compares the intensities of the metal filament lamp and the Hefner lamp, at first placing the Hefner lamp one foot from the photometer head and afterwards placing it more than 100 ft. from the latter, he should not obtain the same result both times. In the first case, owing to the reddish tint of the Hefner lamp, the intensity of the metal filament lamp should appear less. If, again, a second observer, whose colour vision is slightly abnormal, compares the lamps at the first distance, he gets a third result. Of course the difficulty does not arise in practice, because the sources to be compared have usually the same colour and the illumination of the field of the photometer does not vary over a wide range. Still, a standard unit of light should meet all conceivable cases, and we are at present unable to state satisfactorily in terms of our standards, once for all, the candle power of, for example, a mercury vapour lamp. In order to be definite we must specify, first of all, normal colour vision on the part of the observer, and then we must state the illumination of the fields he compares. It is, of course, the Purkinje effect, the change from rod to cone vision, that causes all this trouble. And it is precisely within the range of illumination in common use, 1 to 100 metre-candles, that this change from rod to cone vision takes place.

Comparative effectiveness of UV wavelengths for the inactivation of Cryptosporidium parvum oocysts in water

2001 ◽  
Vol 43 (12) ◽  
pp. 171-174 ◽  
Author(s):  
K. G. Linden ◽  
G. Shin ◽  
M. D. Sobsey
Keyword(s):  
Uv Radiation ◽  
Cryptosporidium Parvum ◽  
Mercury Vapour ◽  
Wide Range ◽  
Mercury Vapour Lamp ◽  
A Cell ◽  
Cryptosporidium Parvum Oocysts ◽  
Cell Culture Assay ◽  
Uv Lamps ◽  
Collimated Beam

Cryptosporidium parvum oocysts in water were exposed to distinct wavelength bands of collimated beam ultraviolet (UV) radiation across the germicidal UV wavelength range (210-295 nm) that were emitted from a medium pressure (MP) mercury vapour lamp. The dose of UV radiation transmitted though each narrow bandpass filter was measured utilising potassium ferrioxalate actinometry. Oocyst infectivity was determined using a cell culture assay and titre was expressed as an MPN. The log10 inactivation for each band of radiation was determined for a dose of 2 mJ/cm2. Doses from all wavelengths between 250-275 nm resulted in approximately 2 log10 inactivation of Cryptosporidium parvum oocyst infectivity while doses with wavelengths higher and lower than this range were less effective. Because polychromatic radiation from MP UV lamps had about the same germicidal activity between the wavelengths of 250-275 nm for inactivation of oocyst infectivity, there was no unique advantage of MP UV over low pressure (LP) UV except for the simultaneous delivery of a wide range of germicidal wavelengths.

scholarly journals Ocean Emission Effects on Aerosol-Cloud Interactions: Insights from Two Case Studies

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Armin Sorooshian ◽  
Hanh T. Duong
Keyword(s):  
Case Studies ◽  
Field Experiments ◽  
Remote Sensing Data ◽  
Anthropogenic Pollution ◽  
Cloud Microphysics ◽  
Marine Aerosols ◽  
Aerosol Cloud ◽  
First Case ◽  
Wide Range ◽  
Aerosol Cloud Interactions

Two case studies are discussed that evaluate the effect of ocean emissions on aerosol-cloud interactions. A review of the first case study from the eastern Pacific Ocean shows that simultaneous aircraft and space-borne observations are valuable in detecting links between ocean biota emissions and marine aerosols, but that the effect of the former on cloud microphysics is less clear owing to interference from background anthropogenic pollution and the difficulty with field experiments in obtaining a wide range of aerosol conditions to robustly quantify ocean effects on aerosol-cloud interactions. To address these limitations, a second case was investigated using remote sensing data over the less polluted Southern Ocean region. The results indicate that cloud drop size is reduced more for a fixed increase in aerosol particles during periods of higher ocean chlorophyll A. Potential biases in the results owing to statistical issues in the data analysis are discussed.

Modelling the effects of inter-observer variation on colour rendition

2017 ◽  
Vol 51 (1) ◽  
pp. 37-54 ◽  
Author(s):  
MJ Murdoch ◽  
MD Fairchild
Keyword(s):  
Colour Vision ◽  
Spectral Characteristics ◽  
Observer Variation ◽  
Light Sources ◽  
Standard Observer ◽  
Natural Range ◽  
Normal Colour ◽  
Range Of Variation

The colour rendition characteristics of light sources are quantified with measures based on CIE standard observers, which are reasonable representations of population averages. However, even among people with normal colour vision, the natural range of variation in colour sensitivity means any individual may see something different than the standard observer. Modelling results quantify the effects of these inter-observer differences on colour rendition measures defined by IES TM-30-15. In general, inter-observer differences tend to be smaller for light sources with high colour fidelity values, and they are affected by spectral characteristics of different lighting technologies. The magnitude of variation in colour rendition measures, up to 5–10 units in IES TM-30-15 ( Rf, Rg), measures is compared with other sources of variability and ambiguity.

scholarly journals Internal volumetric heat generation and heat capacity prediction during a material electromagnetic treatment process using hybrid algorithms

2018 ◽  
Vol 38 (1) ◽  
pp. 74-82
Author(s):  
Edgar García-Morantes ◽  
Iván Amaya-Contreras ◽  
Rodrigo Correa-Cely
Keyword(s):  
Inverse Problem ◽  
Heat Capacity ◽  
Electromagnetic Field ◽  
Heat Generation ◽  
Initial Conditions ◽  
Limited Range ◽  
First Case ◽  
Realistic Situation ◽  
Wide Range ◽  
Volumetric Heat Generation

This work considers the estimation of internal volumetric heat generation, as well as the heat capacity of a solid spherical sample, heated by a homogeneous, time-varying electromagnetic field. To that end, the numerical strategy solves the corresponding inverse problem. Three functional forms (linear, sinusoidal, and exponential) for the electromagnetic field were considered. White Gaussian noise was incorporated into the theoretical temperature profile (i.e. the solution of the direct problem) to simulate a more realistic situation. Temperature was pretended to be read through four sensors. The inverse problem was solved through three different kinds of approach: using a traditional optimizer, using modern techniques, and using a mixture of both. In the first case, we used a traditional, deterministic Levenberg-Marquardt (LM) algorithm. In the second one, we considered three stochastic algorithms: Spiral Optimization Algorithm (SOA), Vortex Search (VS), and Weighted Attraction Method (WAM). In the final case, we proposed a hybrid between LM and the metaheuristics algorithms. Results show that LM converges to the expected solutions only if the initial conditions (IC) are within a limited range. Oppositely, metaheuristics converge in a wide range of IC but exhibit low accuracy. The hybrid approaches converge and improve the accuracy obtained with the metaheuristics. The difference between expected and obtained values, as well as the RMS errors, are reported and compared for all three methods.

scholarly journals Intercalibration of different light-traps and bulbs used in moth monitoring in northern Europe

1998 ◽  
Vol 9 (1) ◽  
pp. 37-51 ◽  
Author(s):  
Reima Leinonen ◽  
Guy Söderman ◽  
Juhani Itämies ◽  
Seppo Rytkönen ◽  
Ilpo Rutanen
Keyword(s):  
The Other ◽  
Northern Europe ◽  
Mercury Vapour ◽  
Light Traps ◽  
Mercury Vapour Lamp ◽  
Species Being ◽  
Tungsten Lamp

Four different combinations of light-traps and bulbs were tested during the summer 1996 in Kainuu, northern Finland: a Jalas model with a 160-W (J/160W) blended light lamp or a 125-W (J/125W) mercury vapour lamp, a Ryrholm trap with a 125-W (R/125W) mercury vapour lamp and a Rothamsted trap with a 200-W tungsten lamp (G/200W). The traps were rotated between four sites every night, but were kept in the same position for the fifth night in order to prevent the possible influence of moonlight. The longest distance between the traps was 150m, and there was no direct visibility between any of them. Three orders were inspected, i.e. Lepidoptera, Coleoptera and Hemiptera, the total numbers of individuals and species being as follows: 20857/425, 862/101 and 1868/58. G/200W collected significantly fewer moths than the other traps. In some cases, J/125W collected significantly more moths and less species than the J/160W design. The R/125W design collected significantly more species than the J/160W design. Similar differences in the effectiveness of the lamps and traps were found in the case of Coleoptera and Hemiptera. Alpha diversities showed the same trend.

Photorearrangement of 2-cyanobicyclo[2.2.1]hept-2-ene. Observation of 1,2- and 1,3-sigmatropic shifts

1982 ◽  
Vol 60 (13) ◽  
pp. 1657-1663 ◽  
Author(s):  
Ikbal A. Akhtar ◽  
John J. McCullough ◽  
Susan Vaitekunas ◽  
Romolo Faggiani ◽  
Colin J. L. Lock
Keyword(s):  
Single Crystals ◽  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Major Product ◽  
Molecular Structures ◽  
Lithium Aluminum ◽  
Mercury Vapour ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Mercury Vapour Lamp

Irradiation of 2-cyanobicyclo[2.2.1]hept-2-ene (2-cyanonorbornene, 4) in hexane, with the full arc of a mercury vapour lamp, gives the rearrangement products 1-cyanobicyclo[4.1.0]hept-2-ene 5 and 7-cyanotricyclo[4.1.0.03.7]heptane 6 in the ratio 20:1. These products were separated by preparative vpc. The structure of the major product 5 was determined by single crystal X-ray analysis. Reduction of 5 with lithium aluminum hydride gave the corresponding primary amine, which was converted to the p-bromobenzenesulfonamide 9, mp 150–151 °C, which gave single crystals from ethanol–water. The crystal and molecular structures are described. The minor product 6 was hydrogenated to give 7-cyanobicyclo[2.2. 1]heptane. Formation of 5 and 6 may involve concerted σ2s + π2s and σ2a + π2a processes respectively, which are photochemically allowed.

A Hospital-Based Cross-Sectional Study to Estimate the Prevalence and Sex Distribution of Colour Vision Deficiency among School Going Children Attending a Tertiary Eye Care Center in Kolkata City, West Bengal, India

2021 ◽  
Vol 8 (32) ◽  
pp. 2962-2967
Author(s):  
Rinki Saha ◽  
Indrajit Sarkar ◽  
Tamojit Chatterjee ◽  
Sandip Samaddar ◽  
Suman Chandra Sen
Keyword(s):  
School Children ◽  
Colour Vision ◽  
Care Center ◽  
Cross Sectional Study ◽  
Sex Distribution ◽  
Cross Sectional ◽  
Colour Vision Deficiency ◽  
Cone Pigments ◽  
Normal Colour ◽  
Colour Blindness

BACKGROUND Colour vision is a function of three types of cone pigments present in the retina. Colour vision deficiency is an important disorder of vision that may pose a handicap to the performance of an affected individual. The prevalence of colour blindness varies in different geographical areas. The identification and estimation of the prevalence of colour vision deficiency in school-going children will help to educate and guide the caregivers to help the children in selecting their profession. This study was done to estimate the prevalence, sex distribution, and types of colour vision deficiency among school-going children of 5 to 15 years. METHODS A cross-sectional observational study was done among 500 students to evaluate the colour vision during the period from 1st January 2018 to 30th June 2019 at the Regional Institute of Ophthalmology, Kolkata. Ishihara’s pseudo isochromatic colour vision chart 38th edition was used to assess the school children for colour vision status. The children who were found to be colour blind were further classified into degree and types of colour vision deficiency. RESULTS A total of 500 students (250 male & 250 female) of surrounding schools, in the age group of 5 years to 15 years, were screened. 480 students (96 %) had normal colour vision while 20 (4 %) students were found to have defective colour vision. Prevalence (4 %) for colour blindness was found to be higher in males (3.6 %) than females (0.4 %). It was observed that out of 20 (4 %) colour-blind subjects 3.6 % were protanopes and 0.4 % were deuteranopes. CONCLUSIONS The present study shows the prevalence of colour blindness found to be quite low (4 %) and more common in males (3.6 %) in comparison to females (0.4 %). Protanomaly (3.6 %) was more common than deuteranomaly (0.4 %). KEYWORDS Colour Blindness, Protanomaly, Deuteranomaly, School Children

scholarly journals A Case of a Persistent Postoperative Infection Caused by Multidrug-ResistantKluyvera ascorbatain the Oral and Maxillofacial Region

2019 ◽  
Vol 2019 ◽  
pp. 1-4
Author(s):  
Si-Hai Zou ◽  
Lu-Ying Zhu ◽  
Yong Li ◽  
Fu-Gui Zhang
Keyword(s):  
Postoperative Infection ◽  
First Generation ◽  
Multidrug Resistant ◽  
Maxillofacial Region ◽  
Gene Encoding ◽  
First Case ◽  
Wide Range ◽  
Antibiotic Management ◽  
Oral And Maxillofacial Region ◽  
Kluyvera Ascorbata

Introduction.Kluyvera ascorbatainfection is rare, but it has been extensively studied because of its potential to cause a wide range of infections and its ability to transfer the gene encoding for CTX-M-type extended spectrumβ-lactamases (ESBLs) to other Enterobacteriaceae.Case Presentation. The authors report a case of a 61-year-old Chinese male with a persistent postoperative infection caused by a multidrug-resistant ESBL-producingK. ascorbata. Following antimicrobial susceptibility testing, he was aggressively treated with gentamicin and levofloxacin with a favorable outcome.Conclusion. To our knowledge, this is the first case report of a persistent postoperative infection caused by a multidrug-resistantK. ascorbatain the oral and maxillofacial region. The authors suggest thatK. ascorbatainfection warrants prompt identification and aggressive antibiotic management, given that ESBL-producingK. ascorbatais resistant to penicillins and first-generation to third-generation cephalosporins.

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