bluuebunny/crossref_metadata_2025 huggingface dataset:
The Universalization of Social Problems: Some Radical Explanations
Authors: Wagner David
Published: December 2008

An increasing variety of social problems have been declared universal problems that "cross all lines" or "can happen to anyone." This paper argues that, while these claims are well-meaning, they often contradict empirical evidence about the clustering of social problems and, hence, must be explored sociologically for their latent meanings. The paper argues that, along with the manifest goals of raising funds for causes and remedying past discrimination, the new universalism supports a growing "upscale" market in services, while obscuring the importance of social class as a critical variable in many social problems.
Planning for Diversity: Preserving Local Manufacturing Jobs in an Era of Global Economic Transformation
Authors: Tait Vanessa
Published: December 2008

The development of Berkeley, Califomia's protected manufacturing zone is an intriguing case of a progressive urban social movement within the context of economic restructuring. While the neighborhood contained all the elements that usually lead to gentrification (industrial flight, high land values, anti-manufacturing sentiment, and wealthier "inmovers"), the process was reversed after a unique community-based economic justice coalition negotiated with local residents, developers, and city officials to institute a protected manufacturing zone. Activists pursued a strategy of retaining manufacturing as part of a larger goal of preserving the city's racial, ethnic, and class diversity and constructed their movement by consciously linking cultural and material politics. This case shows how community mobilization can disrupt what appears to be an inevitable process of capital disinvestment.
Shop Floor Politics and Labor Movements: Democratization in Brazil and South Korea
Authors: Eder Mine
Published: December 2008

The literature on democratic transitions has largely overlooked the role of labor and the micro foundations of labor mobilization in the democratization process. Based on the comparative analysis of labor-management relations, organization of production, and social struggles at the shop floor in two late-industrializing countries, this paper examines the reasons behind increased labor mobilization in Brazil in the early 1980s and South Korea in post-1987. It argues that increased solidarity and mobilization among the workers was a result of arduous work regimes at the shop floor, strict managerial control, and, in the case of South Korea, "company paternalism." While patterns of authoritarian industrialization and relative deprivation of the industrial workers created a fertile ground for labor mobilization, it was the changing labor-management interactions at the shop floor and the growing influence of workplace organizations that strengthened the labor movements in both countries. After taking on the employers, workers could then challenge the state, thus playing a growing role in the process of democratization.
Corporate Crime in the Global Era: The Enimont Case
Authors: Bonanno Alessandro , Constance Douglas H. , Lyman Katherine L.
Published: December 2008

This paper uses a case study methodology and a Critical Theory framework to interpret corporate crimes committed by the transnational corporation Ferruzzi. Building upon the literature on the crisis of Fordism, the globalization of the economy and society, and corporate crime, it is argued that Ferruzzi was involved in a systematic violation of laws. The analysis points to the fact that these behaviors are endemic to capitalism as they are rooted in the contradiction between capital accumulation and substantive democracy in advanced Western societies. Democratic calls for the establishment of broader participation of subordinate classes in the direction of society create obstacles to the action of profit-seeking corporations. Corporations bypass these obstacles through illegal maneuvers which, today, are made possible by the transnational nature of their activities.
Lighting of the Calouste Gulbenkian Museum
Authors: Ribeiro J.S. , Allen W.A. , De Amorim M.
Published: December 2008

The Calouste Gulbenkian Museum in Lisbon, opened in October 1969, houses a fine and varied collection representative of many arts and periods. The Museum was designed specifically to display the collection to best advantage, and in this the lighting of the exhibits is fundamental. The nature and value of the exhibits made it necessary to meet exceptional conservation requirements, and for this reason daylight has been largely excluded from the Museum and illumination throughout is in a low-medium key. However, by careful attention to brightness gradations, planning for adaptation, and by lighting the exhibits individually and relying largely on light reflected from them for general background illumination, effective display has been achieved in an environment that is aesthetically pleasing, often dramatic and which is worthy of this exceptional collection.
Part 3: Analysis and conclusions
Authors: Morley D.I. , Stainsby A.G.
Published: December 2008

The results obtained from the series of subjective tests of colour rendering described in Part 1 are analysed using the theoretical model of the average observer described in Part 2. It is shown that it is valid to transform the observations of colour difference in the category scale into a subjective ratio scale using the method of Part 2. Further, this subjective scale is linearly related to the measured colour difference if a correction is made for colour adaptation. The just noticeable difference seen by the observers in the colour appearance of the eight Munsell samples is shown to be approximately five-and-a-half times the 'minimum perceptible colour difference' of MacAdam's observer. By making use of this relationship a just noticeable special colour rendering index difference is derived for individual test samples.
Lighting and visual perception
Authors: Jay P.A.
Published: December 2008

A brief account of modern views of visual perception is given, related to our knowledge of lighting. There is evidence for thinking that some part of the phenomenon known as brightness constancy is the result of the structure of the nervous system. It is deduced that brightness constancy will hold most accurately where contrasts are low and is liable to break down when they are high. This implies that in lighting for display and dramatic effect contrasts should be increased. The physical implications of this conclusion are developed in three appendices. The results are consistent with current practice.
The calculation of sky haze luminance from street lighting
Authors: Waldram J.M.
Published: December 2008

The University of St Andrews' Astronomy Department possesses an important optical observatory engaged on observations of faint nebulae, measurements which are possible only if the night sky is dark. Proposed improvements in street lighting in the adjacent town might have made observations impossible; an investigation was undertaken. This paper records calculation of the distribution of haze luminance in the sky due to two components of light from street lighting. In this instance it appeared possible to effect a substantial improvement in the street lighting without producing a proportional increase in the sky luminance.
Proposals for a new undergraduate education in lighting
Authors: Stone P.T.
Published: December 2008

It is contended that lighting has not been given the status in educational programmes commensurate with its importance to personal and social life as evidenced by the treatment of lighting in engineering courses as a subsidiary subject only. It is suggested that lighting science should now be recognized as a subject in its own right for a university degree course. This suggestion is particularly relevant to the modern views that the scope of the subject is very great and that the engineering content is small. A degree course in lighting science would provide graduates with the wide-ranging knowledge needed to allow them free movement within the industry, and would provide for the lighting industry and for users trained personnel equipped for senior positions. A syllabus fcr a three-year course in Lighting Science and Design is outlined.
The quality of street lighting installations under changing weather conditions
Authors: Frederiksen E. , Gudum J.
Published: December 2008

Knowledge of the reflection properties of road surfaces is needed for street lighting calculations which take the luminance distribution on the road surface as a criterion of the quality of the lighting. Laboratory measurements of the reflection properties of different road surfaces when wet and dry are described. Measurements are automated and the results recorded digitally for feeding to a computer. The application of the data to street lighting specifications and design are illustrated.
The European glare limiting method
Authors: Fischer D.
Published: December 2008

The basis and development of the glare system now adopted in several European countries are described. From the original Söllner curves, which gave a means for evaluating glare in interior lighting installations, a glare limiting system which can be applied more readily in practice has been developed. The procedure for estimating the glare rating value of an installation and comparing it with the limits adopted is given. The method is intended for use in working interiors only.
Discharge lamps: some aspects of research and development
Authors: Edwards E.F.
Published: December 2008

A review of discharge lamp developments over recent years shows that a reiterative process takes place between advances in fundamental understanding of discharge phenomena and problems revealed as new lamps find practical application. These two aspects of discharge lamp development govern the evolution of new types of lamps and are considered for low pressure sodium lamps, high pressure sodium lamps, fluorescent lamps, high pressure mercury lamps and metal halide lamps. It is apparent that research is as active on well-established types of discharge lamps as on the newer types.
Electrical breakdown in gas-filled incandescent lamps
Authors: Bergmann G. , Gerthsen P.
Published: December 2008

Electrical discharges between heated tungsten filament electrodes in inert gases have been investigated. The gas pressure and filament temperatures were chosen to simulate conditions in gas-filled incandescent lamps. Before breakdown, two distinct current-voltage regions with positive slope were observed; in the first the currents can be regarded as space-charge limited, in the second they are the saturation currents of the cathode. The transition from the first region to the second is caused by positive ions of the inert gas which are created by impact ionization. The final breakdown has to be attributed to a thermal breakdown of the cathode.
Value for money—building economics
Authors: Morris Alan S.
Published: December 2008

The development of buildings in this country uses an increasing part of our capital resources and demands evidence of benefit in financial or social terms. Government imposed limits on expenditure are directed almost entirely at the initial capital cost. A better assessment would be obtained on a basis of total cost. The cost of buildings is often only a small part of the total expense in financing an enterprise. The usefulness of buildings can be much improved by increased standards of artificial lighting. The initial cost of a lighting installation, although small in relation to that of a complete building, should be carefully considered in the overall cost plan.
Appraisals of traffic route lighting installations
Authors: Cornwell P.R.
Published: December 2008

Appraisals of traffic route lighting installations have been carried out by European observers under wet road conditions, and by British observers under both wet and dry road conditions. The appraisals of Continental and British observers under similar conditions have been compared. Relationships between objective measures of luminance, luminance uniformity and glare limitation, and the associated subjective appraisals are discussed. The Glare Mark formula has been tested in the UK under practical conditions, and a study of the contributing variables has led to the development of simplified formulae for dry and wet roads; these formulae give significantly better correlations with mean glare limitation appraisal than does the Glare Mark.
Individual and group differences in discomfort glare responses
Authors: Stone P.T. , Harker S.D.P.
Published: December 2008

Discomfort glare conditions were generated in an experimental viewing cubicle supplied with a variable luminance glare source operated by a manually controlled dimmer. Repeated settings of the four IES discomfort glare criteria were made by forty-one volunteer subjects all of whom were recruited from three different industries and a wide range of employment categories. At the end of twenty days of practice large differences in the settings were found between subjects for each glare criterion and certain differences emerged between each of the three groups. This wide variation is consistent with other studies on sensory discomfort. It is concluded that many different factors are likely to be the cause of such variability and that further research into them is required in order to understand why people are sensitive to glare and other aspects of the physical environment.
Automatic tracing of photometric curves
Authors: Bini Simonetta , Soardo P.
Published: December 2008

A method is described of drawing photometric curves (e.g. isolux, isoluminance curves) for any given lighting system directly through a computer. Particular reference is made to the calculation of illuminance and isolux curves in street lighting. The method consists essentially in calculating the illuminances for a discrete series of points defining an ideal lattice on the road surface, and in direct tracing through a plotter of the isolux curves by linear interpolation of the data obtained. The luminaires are characterized by their luminous intensity distributions. Provision is made for an arbitrary inclination of the optical axis of the luminaire and for any working condition. The application of the method to lighting installations with multiple sources is also considered.
Age, illuminance, visual performance and preference
Authors: Boyce P.R.
Published: December 2008

Relationships between age, illuminance, visual performance and preference are derived from tests in which 150 subjects performed four tasks: self- and externally-paced Landolt-ring charts, conveyor inspection and a tracker task. Replies to questionnaires enabled preferences to be estimated. Performance results indicate a strong interaction between age and illuminance for the Landolt-ring tasks but not for the conveyor or tracker task. Differences in performance of the Landolt-ring task are largely eliminated by an increase in illuminance. The preference results indicate a decrease in task difficulty and an increase in satisfaction as the illuminance is increased.
Development and practice in the daylighting of buildings
Authors: Bell J.A.M.
Published: December 2008

Throughout history daylighting has been a crucial factor in the design buildings. Until this century windows have held a special place in architecture. The effects of locational differences and the controls devised to vary the admission of light are discussed. The relationship between the functional needs of people or processes and the adequacy of light are considered in terms of architectural form. Lighting can be strongly evocative and the way it is used can reinforce philosophical ideas which may be implicit in the expression of a building. The spacing and height of groups of buildings also have a bearing on the problem and are discussed. It is concluded that though it is becoming increasingly difficult to provide the illuminances required for many activities by the use of daylight alone, qualities such as visual relief, contact with the outside world, sunlight and the pleasing effects of modelling associated with daylight must be taken into account.
Current knowledge of visual performance
Authors: Boyce P.R.
Published: December 2008

Threshold, supra-threshold, and physiological measures of visual performance are compared. Present physiological measures are of little use in visual performance research, but threshold and supra-threshold measures can be usefully used. The effects of illuminance, disability and discomfort glare, luminance distribution and colour on visual performance are then reviewed. Illuminance has the most important effect. The only other important variable is that of veiling reflections. The effect of the operational variables of subjects' age, visual capability and the work characteristics are examined and indicate that human factors are more important than physical factors in their effect on visual performance. In the final section the synthesis of existing knowledge of visual performance, presented in CIE Report No. 19, is explained and suggestions made for extending and examining its validity and application. Some general pointers for the direction in which future research might progress are given.
Visual aspects of sunlight in buildings
Authors: Ne'Eman E.
Published: December 2008

It is generally taken for granted that people like sunshine inside buildings, provided thermal and visual discomfort are avoided. Obviously the degree to which sunshine is liked is dependent on climate, tradition and sometimes on prejudice. It is a common practice in building design to deal with the thermal aspects of sunshine and their control, while visual aspects of sunlight are not adequately considered. Recent studies have indicated that as a result of the trend towards improved thermal comfort in buildings, the visual aspects of sunlight have assumed a higher degree of importance for the well being of occupants. Further studies have been made of the effect of the presence of sunlight and also of the degree of exposure of occupants to the Sun.
Some aspects of the tin halide molecular arc
Authors: Drop P.C. , De Groot J.J. , Jack A.G. , Rouweler G.C.J.
Published: December 2008

A high pressure gas discharge lamp with excellent colour rendering can be produced by exploiting the radiation from a tin halide arc. Radiation generation and transfer processes in the tin halide arc are reviewed and problems due to arc instabilities and horizontal operation are discussed. Magnetic stabilization enables the arc to be operated horizontally; a very small magnetic field of about 100 A/m is adequate. The choice of lamp filling is discussed in relation to optimization of luminous efficacy and control of the correlated colour temperature. Chromaticity is improved by the addition of lithium or indium. The influence of impurities on lamp performance is discussed, and the results of experiments on test lamps are presented. There is little decrease in luminous flux with time.
High beam intensity and obstacle visibility
Authors: Helmers G. , Rumar K.
Published: December 2008

Visibility distances to obstacles on the right hand side of a straight two-lane road have been obtained. In high beam with opposing high beam of about the same intensity there are no significant differences in the visibility distance as a function of high beam intensity over about 50000 cd. In high beam with opposing high beam of intensity about three times as large or more there is a large loss in visibility distance (>35%) compared with the situation above. The optimum distance for switching from high to low beam varied between 250 m and 400 m when the two opposing vehicles had about the same high beam intensity. In high beam without opposing glare there is very little gain in visibility in relation to the amount of increase of intensity above 50 000 cd.
Development of integrated ceiling systems
Authors: Bedocs L. , Pinniger M.J.H.
Published: December 2008

The world wide energy crisis indicates the need to examine more critically the consumption of energy by building services. The integrated environmental design (IED) approach to building design has much to offer since one of its purposes is to save energy. One of the elements in IED is the integrated ceiling system which can provide lighting, air-diffusion, sound control and fire protection. The paper examines the development of these systems and the standards to which individual components and assembled systems must be tested. The use of high intensity discharge lamps and luminaires for lighting and air-handling is discussed and the behaviour of the ceiling with negative pressure plenums, and the diffusion of conditioned air from ceilings having shaped or offered contours are also considered.
Artificial lighting fόr commercial horticulture
Authors: Weir J.
Published: December 2008

The considerable investment which has been put into research on the effect of light on plant growth is at last showing a substantial return for the greenhouse industry. The British grower, faced with increasing economic pressures over the past few years, has grasped the opportunity of using this accumulated knowledge and, with the help of various interested research bodies and lamp manufacturers, has created a new lighting technology for plant production. The various lighting techniques at present used in commercial horticulture are discussed together with their economic implications for the grower.
The luminaire domain and the flow of light
Authors: Lynes J.A.
Published: December 2008

The distributive principle is inapplicable to loci of scalar utilance and cylindrical utilance. The British Zonal classification system therefore cannot be used for predicting these quantities; despite this limitation it is concluded that a more widely applicable system of luminaire classification would be unacceptably complicated. Nomogram grids are presented which enable lines of limiting vector/ scalar ratio to be drawn on luminaire domain charts. Every locus of constant vector/scalar ratio in the luminaire domain is also a line of constant wall/task illuminance ratio and a line of constant horizontal/cylindrical illuminance ratio. In a given interior these ratios cannot be independent criteria; each can be expressed in terms of either of the others.
Accuracy of photometry of retroreflectors and retroreflective materials
Authors: Moerman J.J.B.
Published: December 2008

The paper examines the influence of source, receiver and sample dimensions on the accuracy of measurement of the coefficient of luminous intensity of retroreflectors and retroreflective materials. Expressions are developed from which requirements for an acceptable accuracy can be derived. The error caused by a wrong adjustment of the observation angle is also discussed.
Life and luminous flux of halogen incandescent lamps related to filament temperature, pressure and CH2Br2 content
Authors: de Bie J.R. , Ponsioen J.C.M.A.
Published: December 2008

An experimental study has been made of 20 V, 100 W halogen incandescent lamps using different filling pressures for the halogen additive (0. 25-16 torr CH2Br2) and the inert gas Kr (4-16 atm.), and burning at two voltages. The maximum luminous flux and life were found for lamps with halogen filling pressures of 1-4 torr CH2Br2. Lamps with low halogen filling pressures blacken. At high pressures, attack on the cold coil ends determines life. The blackening or non-blackening in general accords with the transport criterion derived from the solubility of tungsten in the gaseous phase. Halogen lamps with properly operating transport cycles fail due to a local temperature increase leading to burning-through of the filament. The experimentally found relation between life, filament temperature and filling pressure agrees approximately with the theory of the radial transport of tungsten in these halogen lamps. A correlation was found between lamp life and the temperature increase of the hot spot.
Performance and comfort in the presence of veiling reflections
Authors: De Boer J.B.
Published: December 2008

Experiments on performance and comfort at visual tasks similar to reading and writing under lighting conditions of veiling reflections show the necessity of basing the lighting design for offices and similar working places on criteria of performance as well as on those of comfort and give rise to doubt as to whether a single relationship between contrast sensitivity and adaptation luminance as mentioned in CIE publication 19 is universally valid. For good visual performance convenient values of average luminance and contrast are required; visual comfort requires a limit to be set to the ratio of luminaire luminance to task illuminance. For normal office work this ratio should be kept smaller than 7 cd/m2/lux.
Proposed changes to the SI system of photometric units
Authors: Jones O.C.
Published: December 2008

It has recently been proposed that the lumen should become the SI base unit for photometry and that it should be defined in terms of the SI unit of power, the watt. The freezing platinum primary standard source would then be replaced by a primary standard detector, for example an absolute radiometer. As a preliminary measure 683 lm/W has been adopted as the conventional value for Km for use in spectroradiometric calculations. The reasoning behind these changes is briefly presented, together with some discussion of the implications.
Use of glass in electric lamps
Authors: Adams O.
Published: December 2008

The term 'glass' refers to a wide range of non-crystalline inorganic materials differing in their compositions and properties. The formation of glasses is discussed: five main types of glass, including vitreous silica, are considered and shown to meet the requirements of materials for envelopes and other components in electric lamps. Brief descriptions are given of the various stages of glass manufacture. Applications of soda-lime and lead glasses in GLS incandescent lamps and fluorescent lamps are described. Reference is made to the special requirements of envelopes for low pressure sodium lamps. Finally the properties of vitreous silica and its use in tungsten-halogen lamps, in high pressure mercury vapour lamps and in metal-halide lamps are considered and the need for the material to be of high purity is emphasized.
Fluorescent lamps with very high luminous efficiency
Authors: Vrenken L.E.
Published: December 2008

Some years ago a new generation of fluorescent lamps with 80 Im/W and a colour rendering index of 85 was developed, which used newly developed phosphors with narrow emission bands. Recent improvements in these phosphors have opened up new possibilities as far as lamp geometries are concerned. For example, 1200 mm 40 W lamps in 25 mm diameter with about 95 Im/W, a colour rendering index of 85 and a lumen maintenance which is better than that of 37 mm diameter 40 W lamps with halophosphate phosphors, can now be realized. The newly developed lamps therefore have 15 to 20% higher efficacies than existing standard lamps, and provide an answer to the increasing demand for energy conservation.
Optimization of road lighting installations by the use of performance sheets
Authors: van Bommel W.J.M.
Published: December 2008

Road lighting performance sheets have been developed to give, for roads of various dimensions and for the four types of road surface standardized by the CIE, the lighting quality values. The level of quality can be determined by the designer according to the specifications applicable. Using the data so obtained as the input to a cost comparison computer program, the optimum road lighting scheme, from the points of view of lighting technology, cost and energy consumption, can be obtained.
The use of metal-halide discharge lamps for film lighting (Part 1)
Authors: Taylor E.W.
Published: December 2008

Intensity variations of light from a discharge lamp, occurring at twice the alternating supply frequency, can lead to a cyclic variation in frame-to-frame exposure if such lamps are used as light sources in motion picture film work. The visibility of picture luminance fluctuations brought about by such exposure variations is discussed, and limits of film exposure variation are recommended. Practical magnitudes of exposure variation are examined. Using these factors, relationships are derived between camera frame frequency and shutter angle, and lamp supply frequency and intensity variation magnitude, such that practical picture luminance variations are not perceptible. An assessment of a 'safe' lamp supply frequency is described, above which the appearance of picture luminance fluctuations may be discounted. The effect of ripple asymmetry (differing magnitudes of successive intensity maxima) is discussed. Experimental techniques for measuring intensity variations under standardized conditions are described, and the characteristics of two currently-available metal-halide discharge lamps are examined.
Problems by the continuous use visual display units
Authors: Stewart Tom
Published: December 2008

Visual Display Units (VDUs) have been hailed as the first step to the wonderful electronic office of the future. They have also been accused of causing cataracts, deterioration in eye sight and even backache. Are they a blessing—by removing tedious and boring paperwork or are they a hazard to health? There is at present no evidence that they can damage health either by radiation or any other effect on eyesight. However, there can be problems of discomfort and fatigue which although temporary, reduce the well being and the efficiency of the user. This paper examines some of these problems and suggests how they can be avoided by the application of ergonomics to the design, implementation and use of VDUs. All too often VDUs represent the only visible part of a major system development which may be being introduced without due regard to human factors. However, when the ergonomics have been taken seriously, VDUs can actually improve clerical work.
An improved method of manufacturing a fluorescent lamp
Authors: Borghi M. , Grenfell J.P. , Rabusin E. , Stephens S.W.
Published: December 2008

An improved technology for the production of fluorescent lamps is described. Coated glass tubes after passing through a baking lehr are loaded, while still hot, onto a single machine equipped with multi-function heads. The machine completes the cycle of sealing, exhausting, cathode conversion, argon filling and tip-off. Mercury is then dosed in the sealed lamp by the high frequency heating of a special cathode shield coated on one side with a mercury releasing alloy and on the other with a getter which acts during the lamp life to absorb impurities released. The optimisation of the argon flushing process is discussed using a mathematical model. Advantages offered by the new process are described.
The life and performance of incandescent lamps
Authors: Jay P.A. , Coomber D.C.
Published: December 2008

The methods used for calculating economic lamp lives by Strange and Prais are examined. It is concluded that neither is completely sound and an alternative formula is developed. The results although differing in detail from those of Strange are broadly in accordance with his findings. The longer economic lives suggested by Prais cannot be justified. No support for any general change in the rated life of electric lamps comes from these figures, but it is suggested that it might be worth offering a long life lamp of relatively low wattage for domestic use. For commercial consumers no single lamp life is likely to cover the range of situations to be found in practice.
A simple mathematical model of illumination from a cloudy sky
Authors: Tregenza P.R.
Published: December 2008

A new mathematical model to simulate the distribution of light from cloudy skies is developed from very simple assumptions on the probability of cloud occurrence and the light transmission of clouds. It enables an overcast sky luminance distribution to be derived from given clear sky and solar illuminances, and the main characteristics of recent survey results to be reproduced.
The effect of task contrast on visual performance and visual fatigue at a constant illuminance
Authors: Stone P.T. , Clarke A.M. , Slater A.I.
Published: December 2008

Three visually demanding tasks: proof reading, search and signal detection, were devised and produced in a range of contrast from 0.09 to 0.87. Each subject performed all three tasks at one contrast for a set time at an illuminance of 200 lux. In order to investigate the visual fatigue effects, ocular responses before and after performance of the tasks were assessed and measurements were taken of muscle balance for esophoria and exophoria, and convergence and divergence break points; changes in accommodation time; and eye movements. A questionnaire was completed by all the subjects at the end of their experimental session, to determine their impressions of the work they had done. All the tasks showed a trend of increasing performance with higher contrast, but for one task the performance showed a significant decrease at the highest contrast and the other tasks indicated a possible decrease there also. The measurements of binocular co-ordination showed a tendency to esophoria after performance of the tasks, but no significant relationship with contrast was found. The accommodation time results were generally unreliable. The eye movement studies showed no relationship with contrast. Some of the questionnaire responses showed trends with contrast similar to the performance results. It is concluded that (a) the visual system experiences difficulty with tasks at very low contrasts, as would be expected and also (b) that very high contrast may inhibit task performance. The latter would not be expected from previous studies and warrants further research, which is at present being undertaken.
The psychological function of windows for the visual communication between the interior of rooms with permanent supplementary artificial lighting and the exterior
Authors: Roessler G.
Published: December 2008

Psychometric model-measurements have been used to investigate the visual contact between the interior of rooms and the exterior. This is considered to be the primary function of windows when using permanent supplementary artificial lighting (PSALI). For the psychological dimensions: enclosure and restraint, privacy, and distraction by the exterior; the influence of illuminance of PSALI, of window width and of the environment seen outside could be proved. Particularly because of the feeling of enclosure and restraint, windowless working spaces and narrow vision windows were rejected. With two windows, a width of 1.5 m to 2 m and an illuminance of about 400 lx to 1200 lx were found to be the optimum.
The dependence of the general colour rendering index on the set of test colours, the standard observer and the colour-difference formula
Authors: Opstelten J.J.
Published: December 2008

The dependence of the General Colour Rendering Index (GCRI) on the specific choice of test colours, standard observer and colour difference formula was investigated using the spectral power distribution (spd) of 29 fluorescent lamps. The conclusion is drawn that the substitution of the CIE 1931 colorimetric observer by the CIE 1964 supplementary observer or of the 1964 CIEUVW colour difference formula by the 1978 CIELUV formula does not significantly influence the ranking of light sources with respect to their GCRI's. Substitution of CIEUVW by CIELAB may have some effect on this ranking although this effect is less than one would expect from the correspondence between CIELAB and CIEUVW colour differences. Replacement of a set of 94 test colours by the CIE set of 8 test colours or by a set of 13 saturated ones has only a minor effect on the ranking. Therefore, there is no reason to change the CIE set of test colours as long as the colour rendering properties of light sources are expressed by a single number, the GCRI. It is shown that we can gain more information on the colour rendering properties of a light source by considering the frequency distribution of the individual CRI's of a large set of test colours. In this investigation special attention was given to the three-band fluorescent lamps. The optimum properties of these lamps appear to depend only slightly on the specific choice of test colours, standard observer and colour difference formula.
Photometric measurement of retroreflection: a new calibration procedure
Authors: Artom M.
Published: December 2008

The problems involved in photometry of retroreflectors are considered: for example, low light levels, heterochromatic photometry, and critical effect of geometric parameters. In order to simulate practical use conditions the visibility of the retroreflector depends on the illumination received in normal driving situations at various distances and incidence angles from the headlamps of the following car and on the luminous itensity retroreflected in the direction of observation. The test apparatus consists of precise realisation of geometric parameters, adequate photometric components and practical calibration procedure with the highest accuracy. A new calibration technique, used at IEN, is here suggested. This requires one uncalibrated reference light source and two uncalibrated photo-detectors instead of calibrated light sources or calibrated photo-detectors as conventional procedures need.
The choice of test distance to control errors in the photometry of round projectors focused at a long distance
Authors: Moerman J.J.B. , Holmes J.G.
Published: December 2008

A simple method of determining the test distance necessary for an accurate measurement of the intensity distribution from a projector or other luminaire is described. A theoretical analysis of a simplified model establishes a theory which is confirmed by a practical example. A diagram illustrates the general rule for prescribing the ratio of the required test distance to the luminaire diameter as a function of the divergence at 80 per cent of the peak intensity, for two levels of accuracy.
A reference distance for the photometry of projectors
Authors: Holmes J.G.
Published: December 2008

A 'Beam Cross-over Distance' is proposed for use in the photometry of projectors, replacing the traditional cross-over point. The percentage error in a short distance measurement of beam intensity is related to the BCoD.
Errors associated with luminance measurements
Authors: Narisada K. , Takeuchi T. , Tamaru S.
Published: December 2008

In luminance measurements of, for example, relatively dark tunnels from the approach road in daytime, considerable errors are sometimes involved. With systematic measurements it has been found that the light from the surrounding field, i.e., outside the measuring field of the luminance meter, causes a considerable amount of veiling luminance, due to scattering in the optical elements incorporated in the luminance meter, which is superimposed on the luminance of the object to be measured. It was found that the angular characteristics of scattering in the optical elements are similar to those in human eyes regarding the equivalent veiling luminance.
Glare from windows: current views of the problem
Authors: Chauvel P. , Collins J.B. , Dogniaux R. , Longmore J.
Published: December 2008

This paper discusses daylight glare as a source of visual discomfort in terms of glare from the unobstructed sky and not glare related to direct or reflected sunlight. There is a difference between the glare experienced from a window and the glare experienced from a large source of artificial light of the same subtended area as the sky, due to the pyschological differences in the visual content of the field of view. There is also a difference in the discomfort glare produced by one small source or a number of small sources and a source with the same glare index subtending a large solid angle, due to the effect of the larger source on the adaptation level of the visual mechanism. The paper reviews the laboratory studies using artificial light sources of large area which were carried out in England and the USA and also the studies using daylight seen through real windows which were carried out in France and in England independently. The link between the practical studies and the laboratory studies is indicated and the derivation of quantitative requirements is shown. The analysis of the theoretical results indicates the effect of the various parameters involved. The conclusion is that discomfort glare from a single window (except for a rather small one) is practically independent of size and distance from the observer but is critically dependent on the sky luminance. Practical guidance is given on the design of windows and their surroundings to reduce the problems of glare from the sky, which is otherwise certain to be uncomfortable for a very large part of the year. The requirements for the balance of interior and exterior luminances are discussed, and a method of calculation and its practical application is put forward.
Detection potential of normal observers at visibility conditions prevailing in automobile night driving
Authors: Huculak P.
Published: December 2008

Laboratory measurements were carried out to determine the detection potential of 25 normal observers engaged in an automobile headlight research programme. An exposure duration was selected to represent search and detection functions of night driving tasks. Target sizes and luminance ranges were chosen to encompass visibility conditions prevailing in automobile night driving. An analytical expression was then derived to yield threshold luminance increments required by normal observers as a function of target size and background luminance.
Optical radiation safety
Authors: Sliney David H.
Published: December 2008

Recent studies of light damage to the retina and studies of the hazards to the eye and skin from laser radiation have permitted the development of occupational exposure limits for optical radiation from lamps and lighting systems. Although concerns for potential hazards from the ultraviolet radiation emitted from some lamps have always existed, few have previously been concerned about potential harm to the eyes from visible radiation. Recent studies show that short wavelength light may in some instances be harmful to the retina. Furthermore, infrared radiation hazards to the eye are probably less than was once believed. Exposure limits for ultraviolet radiation and guidelines for visible and near-infrared radiation have been promulgated in the USA and some other countries. A proper understanding of the changing nature of environmental exposures to sunlight throughout the day permits the development of exposure limits for repeated, chronic exposure. The use of the present limits and guidelines for a given lamp or lighting system requires a careful study of exposure conditions if realistic control measures are to be devised. Misunderstanding of the limits or failure to consider realistic exposure conditions can lead to unwarranted concerns regarding lamp safety.
The energy management of artificial lighting use
Authors: Crisp V.H.C. , Henderson G.
Published: December 2008

Drawing on the understanding of occupants' lighting use gained from previous BRE behavioural studies, the potential benefits of controls for electric lighting, such as energy saving or reduced installation costs, are described on a qualitative and, where possible, a quantitative basis. The paper reviews the options available for controlling lighting use, exploiting daylight and occupancy linking and various methods of central control including mains signalling, low voltage communication and remote ('wireless') signalling, discriminating between those that are technically feasible and those that have been developed from feasibility to 'off the shelf' systems.
Elements of visual performance
Authors: Inditsky B. , Bodmann H.W. , Fleck H.J.
Published: December 2008

Visual performance is the combined result of foveal and extrafoveal perception per glimpse and saccadic eye movements. These processes are linked to the contrast metric of visibility as developed by Blackwell. The concept of visibility lobes per glimpse related to foveal visibility levels and simple strategies of ocular scanning provide an operational tool for analysis and design of visual tasks and lighting conditions.
Vertical line production of low-mercury content fluorescent tubes
Authors: Rabusin E. , Perego R.
Published: December 2008

Liquid mercury is eliminated from a fluorescent lamp production machine, on which lamps are processed while in a vertical position, and replaced by a cathode shield coated with a highly stable mercury alloy and a non-evaporable getter. The modifications lead to an 18 per cent increase in production speed, more uniform lamp quality and superior performance throughout life. Reduced machine maintenance also contributes to process economy. Ecological benefits are considerable as much less mercury per lamp is utilised. Mercury levels in the factory air have been substantially reduced and the abnormally high values of urine mercury found in operators working in or near previously contaminated zones are now falling towards the normal biological background limits.
Luminance level conversions to assist lighting engineers to use fundamental visual data
Authors: Trezona P.W.
Published: December 2008

There is often a need for the lighting engineer to apply results of visual experiments, conducted under laboratory conditions, to normal viewing situations. But whereas the latter implies use of the eye's natural pupil, the former may well employ a smaller, artificial pupil. The effect of this on luminance level is discussed and conversion tables are provided.
The Monte Carlo method in lighting calculations
Authors: Tregenza P.R.
Published: December 2008

The paper reviews the principles of the Monte Carlo method and describes specific techniques for its application in interior lighting calculations. Its use for computer graphics is discussed, and it is compared with the finite element method for computing inter-reflections.
Non-destructive monitoring of high pressure sodium arcs
Authors: Zollweg R.J. , Kussmaul K.L.
Published: December 2008

A system based on spectroscopic and voltage measurements has been developed to monitor the sodium and mercury partial pressures in high pressure sodium lamps. With this method the amalgam composition and reservoir temperature can be determined to good precision. Application to a number of lamp problems are discussed.
Evaluation of a twin-rotation-disc visibility meter
Authors: Bao C. , Bodmann H.W.
Published: December 2008

Some principal characteristics of a twin-rotation-disc visibility meter are investigated with respect to the constancy of total luminance at the observer's eye, to the temporal modulation of the task and veiling light path and to the contrast transmission. By means of an additional veiling light source and an additional neutral density filter in the task light path the performance and applicability of the visibility meter can be improved. The accuracy of the theoretical contrast transmission is limited by residual stray light.
Kinetic luminance measurement and assessment of road tunnels
Authors: Hartmann E. , Finsterwalder J. , Müller M.
Published: December 2008

A measurement method for recording adaptation luminances at road tunnels under actual traffic conditions is described and the application of the results discussed. For conducting the survey, a photometer with a recording instrument was installed in a vehicle. The luminance of the road track, the tunnel walls can be recorded, and also, with a glare lens, the veiling luminance. The measurements were made from the driver's position taking into account effects caused by the vehicle (windscreen, etc.) and the speed. Recordings of a tunnel can be conducted in a relatively short time, so that the flow of traffic is not impaired. With the assessed luminance data the adaptation luminance can be calculated and different tunnels can be compared. To characterise a tunnel under physio-optical aspects, a criterion is proposed.