China
Africa
Explore chapters and articles related to this topic
Photoacoustic Depth Determination and Imaging of Port Wine Stain Birthmarks
Published in Lihong V. Wang, Photoacoustic Imaging and Spectroscopy, 2017
John A. Viator, Roy G.M. Kolkman, Wiendelt Steenbergen
The experimental apparatus shown in Figure 37.1 consisted of a frequency-doubled Nd:YAG laser (Quantel Brilliant, Big Sky Laser, Bozeman, MT) operating at 532 nm, with a pulse duration of 4 ns. The beam was split and focused by plano-convex lenses into two 1,500 μm fibers. To avoid optical breakdown of the fibers, a neutral density filter with a 0.9 optical density was used to attenuate the laser energy. The beam energy was 180 mJ with a pulse repetition rate of 10 Hz. Laser energy at the output of each fiber was 11 mJ. The laser spot area was determined by irradiating thermal paper. The radiant exposure was then calculated to be 0.08 J/cm2.
Laser Basics
Published in Ken Barat, Laser Safety Management, 2017
A CW laser has a steady power output, measured in watts. For pulsed lasers, the output generally refers to energy, rather than power. Radiant energy is a function of time and is measured in joules. Two terms are often used when measuring or calculating exposure to laser radiation. Radiant exposure is the radiant energy divided by the area of the surface the beam strikes. It is expressed in joules per square centimeter. Irradiance is the radiant power that strikes a surface divided by the area of the surface over which the radiant power is distributed. It is expressed in watts per square centimeter.
General Introduction
Published in Neha Gupta, Gopal Nath Tiwari, Photovoltaic Thermal Passive House System, 2022
The following are a few terms commonly used in solar energy applications:Irradiance: It is the rate at which radiant energy is incident on the per unit area of surface measured in W/m2.Irradiation or radiant exposure: The incident energy (irradiance) per unit area of surface in J/m2 over a specified time (an hour or a day) obtained by integrating beam/diffuse/total radiation. The term insolation is specifically used for solar energy irradiation. Insolation per day (H) and insolation per hour (I) can represent beam/diffuse/total radiation for surface of any orientation.Magnitude of normal irradiance in a terrestrial region can be calculated using Equation (l.4b). The magnitude of diffuse radiation (directionless) depends on (Iext − IN) and can be calculated from the expression proposed by Singh and Tiwari [19]. Id=K1Iext−INcosθZ+K2where the numerical values for K1 and K2 for different weather conditions are given in Appendix A. Equation (1.7) is applicable to horizontal surface (tangential surface to the observer at outer surface of Earth).Radiosity or radiant existence: The rate at which radiant energy leaves a surface per unit area by reflection and transmission in W/m2.Emissive power or radiant self-existence: The rate at which radiant energy leaves a surface per unit area by emission in W/m2.Further, the weather classifications for a given climatic condition are defined according to sunshine hours (N) and ratios of daily diffuse to daily global radiation. These are briefly described as in Table 1.4Appendix C gives the hourly variation of ambient air temperature and solar intensity for different months for various stations in India.A program developed for estimating solar radiation at an inclined angle is offered in Appendix D.
Comparison of Static and Ambulatory Measurements of Illuminance and Spectral Composition That Can Be Used for Assessing Light Exposure in Real Working Environments
Published in LEUKOS, 2019
Mathias Adamsson, Thorbjörn Laike, Takeshi Morita
One conclusion from the study is that there are large differences between a static measurement of illuminance and irradiance in a room and the luminous and radiant exposure measured with an ambulatory instrument. The limited number of static measurements of illuminance and spectral composition of the light carried out with the measurement protocol in this study does not appear to be sufficient to provide an adequate representation of the lighting conditions that a person is exposed to in the working environment. The t-tests comparing the means for the group of 15 subjects show a relationship between ambulatory measurements and static measurements of vertical illuminance at the eye in the normal angle of gaze, but the correlations that were carried out indicate that a higher resolution of static measurements may be needed in order to determine the light exposure for the individual subjects.
Experimental validation of a wireless monitored solar still for efficient olive pomace drying and distilled water production
Published in Drying Technology, 2023
Antonio Rodríguez Orta, Roque Aguado Molina, Manuel Sánchez Raya, David Vera Candeas, Juan Antonio Gómez Galán
Another key factor to evaluate the correct functioning of the solar still prototype is the calculation of the drying thermal efficiency () using Eq. (5), similarly to the procedure reported by Baniasadi et al. [32]. In drying processes, the drying thermal efficiency is usually defined as the ratio of the energy used for the moisture evaporation to the total thermal energy input for drying [7, 38]. For the particular case of the solar still prototype, this parameter is calculated as the energy required to remove a certain amount of moisture from the sample divided by the actual solar radiant energy that reaches the glazed window [35]. The drying thermal efficiency is also referred to in the scientific literature as system efficiency or drying efficiency [35]. For calculation of the drying thermal efficiency, it is essential to determine the total solar radiation that fell onto the glass surface during the period of study, based on the data obtained during the monitoring shown in Figure 11. where is the mass of dry (moisture-free) sample (kg), H is the solar radiant exposure (MJ m) and is the glass surface on which the solar radiation strikes (0.364 m2). The solar radiant exposure (H) is the solar irradiance of a surface (E) integrated over the time of irradiation (t), as shown in Eq. (6).
Monowave and polywave light-curing of bulk-fill resin composites: degree of conversion and marginal adaptation following thermomechanical aging
Published in Biomaterial Investigations in Dentistry, 2021
Sheila Celia Mondragón Contreras, Ana Luiza Barbosa Jurema, Evaniele Santos Claudino, Eduardo Bresciani, Taciana Marco Ferraz Caneppele
Two different LCUs were selected for this study, an MW LED curing unit (3M ESPE, Sumaré, Brazil) and a blue-violet PW LED curing unit (Bluephase N, Ivoclar Vivadent, Schaan, Liechtenstein). The LCUs were used in the high-intensity continuous mode, with a curing time of 20 s. Table 1 presents information about the LCUs. The irradiance (mW/cm2), radiant exposure (J/cm2) and spectral emission (nm) delivered by the LCUs were checked using a simulation device (Managing Accurate Resin Curing – Patient Simulator (MARC-PS)) (BlueLight Analytics, Halifax, Canada).