Optical radiation emissions from compact fluorescent lamps

There is a drive to energy efficiency to mitigate climate change. To meet this challenge, the UK Government has proposed phasing out incandescent lamps by the end of 2011 and replacing them with energy efficient fluorescent lighting, including compact fluorescent lamps (CFLs) with integrated ballasts. This paper presents a summary of an assessment conducted by the Health Protection Agency in March 2008 to evaluate the optical radiation emissions of CFLs currently available in the UK consumer market. The study concluded that the UV emissions from a significant percentage of the tested CFLs with single envelopes may result in foreseeable overexposure of the skin when these lamps are used in desk or task lighting applications. The optical output of all tested CFLs, in addition to high-frequency modulation, had a 100-Hz envelope with modulation in excess of 15%. This degree of modulation may be linked to a number of adverse effects.     

Ultraviolet radiation emitted by compact fluorescent lamps

To meet the objective of energy efficiency, increasing emphasis on use of energy saver compact fluorescent lamps (CFLs), makes it necessary to analyze the effect of radiation especially ultraviolet (UV) radiation on human health. Various types of CFLs in terms of various shapes, sizes and electrical powers are studied for UV content present in their radiation. Various parameters such as UV irradiance, ratio of UV irradiance to electrical power (η) and ratio of UV power to luminous flux (k), for eighteen types of CFLs are studied to dictate their performance. As expected, both the UV output power and the luminous flux are reduced in the case of double envelope CFLs in comparison to single envelope CFLs, however, the k value is reduced more effectively. For all types of CFLs under study, k₁ for UVA remains less than 104 μW/lm, which is a safe limit for UVA. However, the study demonstrates that the use of CFLs might be detrimental to human health if these are used at shorter distance, e.g., in table lamps.     

Spot measurements of intermediate frequency electric fields in the vicinity of compact fluorescent lamps

Starting in 2009, certain types of incandescent light bulbs will be withdrawn from the market in the European Union and elsewhere. However, compact fluorescent lamps that are among the candidates to replace them produce intermediate frequency electric fields (EFs) much higher than any other device or appliance previously available to the general public. Measurement results of these EFs showed that the maximum recorded EF strength in the 1.2-100 kHz frequency range in close proximity to the lamps was > 42 V m(-1) for all tested lamps. In nine cases, the field strength exceeded 87 V m(-1) and the highest measured value was 216 V m(-1).     

Variation of the instantaneous luminous flux of fluorescent lamps fed by dimmable electronic ballasts with frequency control

Effects of hysteresis and inertial processes on the instantaneous luminous flux of fluorescent lamps (FLs) are experimentally investigated, which are fed by frequency controlled, dimmable, electronic ballasts. Other phenomena are also examined, such as the time displacement between the light ripple and the waveform of the electrical power of the lamp, the 'modulation' of the instantaneous luminous flux waveform and generally, the behaviour of the lamp at varying high frequency (HF) levels. For a typical FL, fed by dimmable electronic ballast with frequency control, inertial processes are reduced, as the operating frequency of the lamp decreases. The time displacement between the instantaneous luminous flux and the lamp power has maximal and minimal as frequency varies. As frequency of the FL increases, the diffusion of the metastable states of the Hg atoms is enhanced and the 'modulation' of the instantaneous luminous flux decreases. The hysteresis and the looping of lamp's voltage-current and luminous flux- current characteristics at various frequency levels indicate that it is necessary to add an inductance and a capacitance to the equivalent electrical circuit of a FL at HFs.     

Radioactivity contents in dicalcium phosphate and the potential radiological risk to human populations

Potentially harmful phosphate-based products derived from the wet acid digestion of phosphate rock represent one of the most serious problems facing the phosphate industry. This is particularly true for dicalcium phosphate (DCP), a food additive produced from either sulphuric acid or hydrochloric acid digestion of raw rock material. This study determined the natural occurring radionuclide concentrations of 12 DCP samples and 4 tricalcium phosphate (TCP) samples used for animal and human consumption, respectively. Metal concentrations (Al, Fe, Zn, Cd, Cr, As, Hg, Pb and Mg) were also determined. Samples were grouped into three different clusters (A, B, C) based on their radionuclide content. Whereas group A is characterized by high activities of ²³⁸U, ²³⁴U (10³ Bq kg⁻¹), ²¹⁰Pb (2 × 10³ Bq kg⁻¹) and ²¹⁰Po (800 Bq kg⁻¹); group B presents high activities of ²³⁸U, ²³⁴U and ²³⁰Th (10³ Bq kg⁻¹). Group C was characterized by very low activities of all radionuclides (<50 Bq kg⁻¹). Differences between the two groups of DCP samples for animal consumption (groups A and B) were related to the wet acid digestion method used, with group A samples produced from hydrochloric acid digestion, and group B samples produced using sulphuric acid. Group C includes more purified samples required for human consumption. High radionuclide concentrations in some DCP samples (reaching 2 × 10³ and 10³ Bq kg⁻¹ of ²¹⁰Pb and ²¹⁰Po, respectively) may be of concern due to direct or indirect radiological exposure via ingestion. Our experimental results based on ²¹⁰Pb and ²¹⁰Po within poultry consumed by humans, suggest that the maximum radiological doses are 11 ± 2 μSv y⁻¹. While these results suggest that human health risks are small, additional testing should be conducted.     

Synthesis of C-N co-doped nano-CeO2 and dye degradation under compact fluorescent lamp irradiation

Carbon and nitrogen (C-N) co-doped nano-CeO2 was synthesized by the solvothermal method using hexamethylenetetramine (HMT) as a precipitator at 140 degrees C for 24 h. We found that the degradation of acid orange 7 (AO7) was 94.4% and 98.8% with C-N co-doped nano-CeO2 upon irradiation with a 100-watt high-pressure mercury lamp (HML) and a 10-watt compact fluorescent lamp (CFL), respectively. By comparison, TiO2 degraded 68.4% and 43.0% of the AO7 irradiated by HML and CFL, respectively. We found that the degradation efficiencies of AO7 upon irradiation with the 10-watt CFL in the presence of the samples synthesized using different precipitators decreased as follows: CeO2(HMT)> CeO2-TiO2(HMT) > TiO2(HMT) > CeO2(NaHCO3) > CeO2(Na2CO3).     

Cognitive determinants of risk perceptions associated with biotechnology

Previous research on risk perception suggests that levels of education and information influence concerns over the effects of new technology. This article reports analysis of the impact of several cognitive factors (including education and knowledge) on the perception of risks attributed to applications of modern biotechnology (based on genetic engineering) to food production and agriculture. Using data from a 1992 US-nationwide telephone survey the statistical research identifies those cognitive factors that significantly influence risk perceptions. Additionally, the study reveals those potential influences that, despite their prominence in political and popular debates on risk communication and science education, do not determine the perception of risks on biotechnology in any significant manner. This paper is based on work supported by the Extension Service, U. S. Department of Agriculture, North Carolina State University, and Colorado State University under special project number 91-EXCA-3-0155.     

Modelling the direct virus exposure risk associated with respiratory events

The outbreak of the COVID-19 pandemic highlighted the importance of accurately modelling the pathogen transmission via droplets and aerosols emitted while speaking, coughing and sneezing. In this work, we present an effective model for assessing the direct contagion risk associated with these pathogen-laden droplets. In particular, using the most recent studies on multi-phase flow physics, we develop an effective yet simple framework capable of predicting the infection risk associated with different respiratory activities in different ambient conditions. We start by describing the mathematical framework and benchmarking the model predictions against well-assessed literature results. Then, we provide a systematic assessment of the effects of physical distancing and face coverings on the direct infection risk. The present results indicate that the risk of infection is vastly impacted by the ambient conditions and the type of respiratory activity, suggesting the non-existence of a universal safe distance. Meanwhile, wearing face masks provides excellent protection, effectively limiting the transmission of pathogens even at short physical distances, i.e. 1 m.     

氯氧化锆的放射性分析

氯氧化锆的放射性由主要生产原料锆英砂带入.产地不同,锆英砂放射性相差较大.通过统计分析,对几个主要产地的锆英砂和其制品氯氧化锆的放射性进行比较研究.锆英砂比活度控制在一定范围内时,不同产地的锆砂所产出氯氧化锆,其放射性基本相似,没有明显的差异.     

A new method for assessing the risk of accident associated with darkness

This paper presents a new method for assessing the risk of accidents associated with darkness. The method estimates the risk of accident associated with darkness in terms of an odds ratio, which is defined as follows: [(number of accidents in darkness in a given hour of the day)/(number of accidents in daylight in the same hour of the day)]/[(Number of accidents in a given comparison hour when the case hour is dark)/(Number of accidents in a given comparison hour when the case hour is in daylight)]. This estimate of the risk of accident associated with darkness does not require data on exposure, but relies on the count of accidents in the same pair of hours throughout the year. One of the hours is dark part of the year, but has daylight the rest of the year. The comparison hour, which has daylight the whole year, is used to control for seasonal variations. The aim of relying on the same pair of hours throughout the year is to minimise the influence of potentially confounding factors. Estimates of the risk of injury accidents associated with darkness are developed on the basis of accident data for Norway, Sweden and the Netherlands. It is found that the risk of an injury accident increases by nearly 30% in darkness in urban areas, by nearly 50% in rural areas, and by about 40% for urban and rural areas combined (adjusted estimate).     

不确定度对粉煤灰放射性测得值的评定

粉煤灰在建筑材料中运用越来越广泛,建筑材料中存在放射性问题,逐渐受到了人们的广泛关注。采用多道Y能谱仪对粉煤灰放射性的测量值只是被测量的估计值,测量值可能有无穷多个,但分散性通常是有界的,按照GB 6566-2010《建筑材料放射性核素限量》规定,需符合不确定度的要求,通过不确定来评定粉煤灰放射性测得值尤为重要。     

Human risk factors associated with pilots in runway excursions

A breakdown analysis of civil aviation accidents worldwide indicates that the occurrence of runway excursions represents the largest portion among all aviation occurrence categories. This study examines the human risk factors associated with pilots in runway excursions, by applying a SHELLO model to categorize the human risk factors and to evaluate the importance based on the opinions of 145 airline pilots. This study integrates aviation management level expert opinions on relative weighting and improvement-achievability in order to develop four kinds of priority risk management strategies for airline pilots to reduce runway excursions. The empirical study based on experts’ evaluation suggests that the most important dimension is the liveware/pilot’s core ability. From the perspective of front-line pilots, the most important risk factors are the environment, wet/containment runways, and weather issues like rain/thunderstorms. Finally, this study develops practical strategies for helping management authorities to improve major operational and managerial weaknesses so as to reduce the human risks related to runway excursions.     

Powered two-wheeler drivers’ crash risk associated with the use of bus lanes

Context

Authorizing powered two-wheeler drivers to drive in lanes reserved to buses is a measure that is sometimes mentioned to improve mobility conditions for these users. But what effect would this measure have on the safety of these users and on the safety of the other users with whom they share the traffic space?

Objective

The objective of this study is to contribute elements to help answer this question. More precisely, the objective is to estimate the risk of having an accident per kilometer driven by powered two-wheeler drivers who drive in bus lanes and to compare this risk with that of powered two-wheeler drivers who drive in general traffic lanes.

Method

Using the bodily injury accidents recorded by the police over two years on 13 roads in the city of Marseille and a campaign of periodical observations of powered two-wheeler traffic, we estimated the risk per kilometer driven by powered two-wheeler drivers who drive in bus lanes and compared it with that of drivers who do not drive in them.

Results

The results show that the risk for powered two-wheeler drivers who drive in bus lanes of being involved in a bodily injury accident is significantly higher than the risk run by drivers who drive in general traffic lanes. For the 13 roads studied, it is on average 3.25 times higher (95% CI: 2.03; 5.21).

Conclusion

In the current situation, powered two-wheeler drivers who drive in bus lanes are less safe than those who drive in general traffic lanes. The analysis of police reports suggests that part of this increased risk comes from collisions between automobile drivers turning right and powered two-wheelers driving in the bus lane who continue straight ahead.     

Detection of the molecular changes associated with oral cancer using a molecular-specific fluorescent contrast agent and single-wavelength spectroscopy

There is currently no standard screening technique for oral cancer and its precursors other than visual identification and biopsy of suspicious lesions. To aid noninvasive early detection of oral neoplasia in vivo, we previously developed a molecular-specific contrast agent targeted against epidermal growth factor receptor. Here, we present a simple fluorescence spectroscopy system to detect the presence of this contrast agent in biological models representative of living tissues in order to demonstrate the feasibility of using a spectroscopy system in conjunction with a contrast agent as a screening technique for oral cancer. The spectroscopy system was tested for the ability to detect the contrast agent in four in vitro models: multilayer tissue phantoms made of cells pre-labeled with the contrast agent, multilayer tissue phantoms labeled with the contrast agent from the surface in conjunction with a permeability enhancing agent, fresh tissue slices from normal and abnormal oral cavity biopsies, and whole normal and abnormal oral cavity biopsies. The optical signal from samples labeled with the contrast agent was 3--32 times stronger compared to controls and was detected with a signal-to-noise ratio greater than 10. These results demonstrate that an inexpensive and simple spectroscopy system can be used in biological models of living systems to detect the optical signal from a contrast agent targeted toward a cancer-related biomarker with good signal-to-noise ratios. Coupling inexpensive fluorescence spectrometers with molecular-specific contrast agents has the potential to improve the early detection of oral neoplasia by providing a low-cost screening tool.     

浅谈北美LED节能灯检测要点

全球能源短缺情况日益严重,绿色环保产品取代传统产品必将成为主流.LED节能灯是近年新研制出来的照明产品,LED节能灯采用冷光源技术,具有发热小、耗能少、寿命长等特点,具有巨大的市场发展空间.LED节能灯这个新行业在我国正处于萌芽发展阶段,大大小小的节能灯制造厂如雨后春笋,不断涌现.     

Longitudinal shear properties of human compact bone and its constituents,and the associated failure mechanisms

Human compact bone specimens were tested in longitudinal shear at two different strain rates. The maximum stress and energy absorption capacities were 50.40±14.08 MN m^–2 and 20720±9310J m^–2 respectively for 14 embalmed specimens tested at a cross head speed of 2.1×10^–6 m sec^–1. The maximum stress was found to be 75% of the transverse shearing strength. Bone specimens were also tested after selectively dissolving the organic and mineral components. The results showed that the composite strength of bone was much higher than the summation of strengths of its organic and mineral phases. Fractographic examination of the fracture surfaces showed that debonding of the interfaces between the osteons and the surrounding bone matrix and between the osteonal lamellae were the main mechanisms of longitudinal shear failure.     

Self reported risk taking and risk compensation in skiers and snowboarders are associated with sensation seeking

In alpine skiing, a controversial discussion has been taking place regarding the potential influence of wearing a ski helmet on the individual level of risk taking behaviour. The aim of this study was to evaluate whether self reported risk taking behaviour and self reported risk compensation are associated with the personality trait sensation seeking (SS) in alpine skiing and snowboarding. In total, 683 persons (36% males and 64% females) completed an online-survey about attitudes and use of protective gear in winter sports including the German version of the sensation seeking scale form V. A logistic regression analysis including gender, age, nationality, preferred winter sport, self reported skiing ability, mean skiing time per season, use of ski helmets, and SS total score was used to estimated adjusted odds ratios (ORs) and their 95% confidence intervals (95 CI) for self reported risk taking behaviour. Regression analysis revealed that a more risky behaviour increased with male gender (OR: 2.7), with an age < 25 years (OR: 1.6), with skiing (OR: 1.3), higher skill level (OR: 5.7), and a mean skiing time > 28 days per season (OR: 2.2). In addition, SS total score was significantly higher in more risky compared to more cautious people (23.8 vs. 20.3, p < .001). Ski helmet use was not found to be predictive for a more risky behaviour (p > .05). Also, skiers and snowboarders with self reported risk compensation while wearing a ski helmet had higher SS total scores compared to those who did not report risk compensation (23.8 vs. 20.9, p = .001). In addition, self reported risk compensation in helmet wearers increased with an age < 25 years (OR: 2.2), a higher skill level (OR: 2.5) and a mean skiing time > 28 days per season (OR: 2.1). In conclusion, self reported risk taking and self reported risk compensation are associated with higher sensation seeking total scores. The personality trait sensation seeking, not wearing of a ski helmet, appears to be associated with riskier behaviour on the ski slopes.