Correlation Between Ultraviolet Radiation and Global Radiation in Riyadh, Saudi Arabia

1994 ◽  
Vol 116 (1) ◽  
pp. 63-66 ◽  
Author(s):  
A. M. Mujahid
Keyword(s):  
Saudi Arabia ◽  
Ultraviolet Radiation ◽  
Global Radiation ◽  
Mean Value ◽  
Horizontal Surface ◽  
Monthly Average ◽  
Hourly Basis ◽  
Regression Correlation ◽  
Good Agreement

The global ultraviolet and global radiation were measured and recorded on an hourly basis in Riyadh, Saudi Arabia (lat. 24.6°N, long. 46.7°) during the period 1984–1989. Global radiation, G, was measured by an Eppley PSP pyranometer (0.285≤λ≤2.8 μm) and an Eppley TUVR radiometer (0.29≤λ≤0.385 μm) was used for the measurement of the ultraviolet radiation, UV. Both instruments were mounted on a horizontal surface. The results showed that the monthly average daily ultraviolet radiation was 197.6 Whm−2. The ratio of the monthly average daily ultraviolet radiation to the monthly average daily global radiation (Ku) varied between 0.031 to 0.037, with a mean value of 0.034. Comparison with results obtained in Kuwait, Dhahran, and Makkah showed that the data of Riyadh are in good agreement with those of Makkah and Dhahran; however, it underestimates Kuwait data. A regression correlation between Ku and KT (the ratio of the monthly average daily values of global radiation to extraterrestrial radiation) is developed. Another regression correlation between ultraviolet and global radiation on an hourly basis is also developed.

Ultraviolet Solar Radiation Over the Caribbean Island of Puerto Rico

Solar Energy ◽  
2004 ◽  
Author(s):  
Karim Altaii ◽  
Ramiro L. Rivera
Keyword(s):  
Puerto Rico ◽  
Solar Radiation ◽  
Ultraviolet Radiation ◽  
Global Radiation ◽  
Time Frame ◽  
Published Data ◽  
Caribbean Island ◽  
Monthly Average ◽  
The Caribbean ◽  
Ultraviolet Solar Radiation

Ultraviolet solar radiation was measured and recorded on a 5-minute, hourly and daily basis at four sites on the Caribbean island of Puerto Rico (located from 18° to 18° 30’N latitude and from 65° 30’ to 67° 15’W longitude) over a 24 calendar month time frame. Data were measured by an Eppley Total Ultraviolet Radiometer (TUVR) mounted on a horizontal surface (0.285 ≤ λ ≤ 0.385 μm wavelengths). This data presents the first published data on ultraviolet radiation over Puerto Rico. The data sheds new light on the ultraviolet radiation characteristics of this tropical island. Characteristics such as the daily average, monthly average hourly, monthly average daily, and annual average daily ultraviolet radiation are presented. The ratio of the monthly average daily ultraviolet radiation to the monthly average daily global radiation varied between 0.0476 and 0.0498, with a mean value of 0.0487 ± 0.0009. A regression correlation between ultraviolet and global radiation on an hourly basis is also developed.

Knowledge regarding the importance of ultraviolet radiation and protective behaviors for the eye health in Saudi Arabia

2021 ◽  
pp. 133-139
Author(s):  
Rawan Al-Abdulqader ◽  
Fahad Wadani ◽  
Noura Alkulaib ◽  
Mareyah Husain ◽  
Yasmeen Almulhim ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Ultraviolet Radiation ◽  
Protective Behaviors ◽  
Eye Health

Simulation of Unsteady Flow Around a Cylinder

2015 ◽  
Vol 3 (2) ◽  
pp. 28-49
Author(s):  
Ridha Alwan Ahmed
Keyword(s):  
Stokes Equations ◽  
Lift Coefficient ◽  
Reynolds Numbers ◽  
Mean Value ◽  
Navier Stokes ◽  
Cylinder Surface ◽  
Navier Stokes Equations ◽  
Flow Around A Cylinder ◽  
Numerical Grid ◽  
Good Agreement

       In this paper, the phenomena of vortex shedding from the circular cylinder surface has been studied at several Reynolds Numbers (40≤Re≤ 300).The 2D, unsteady, incompressible, Laminar flow, continuity and Navier Stokes equations have been solved numerically by using CFD Package FLUENT. In this package PISO algorithm is used in the pressure-velocity coupling.        The numerical grid is generated by using Gambit program. The velocity and pressure fields are obtained upstream and downstream of the cylinder at each time and it is also calculated the mean value of drag coefficient and value of lift coefficient .The results showed that the flow is strongly unsteady and unsymmetrical at Re>60. The results have been compared with the available experiments and a good agreement has been found between them

Solar Radiation Over the Caribbean Island of Puerto Rico

Solar Energy ◽  
2004 ◽  
Author(s):  
Ramiro L. Rivera ◽  
Karim Altaii
Keyword(s):  
Puerto Rico ◽  
Solar Radiation ◽  
Global Radiation ◽  
Global Solar Radiation ◽  
Time Frame ◽  
Daily Basis ◽  
Caribbean Island ◽  
Monthly Average ◽  
Energy Conversion System ◽  
The Caribbean

Solar radiation was measured and recorded on a 5-minute, hourly and daily basis at a number of sites on the Caribbean island of Puerto Rico (located from 18° to 18° 30’N latitude and from 65° 30’ to 67° 15’W longitude) over a 24 calendar month time frame. The global solar radiation was measured at four sites (namely: Aguadilla, Ponce, Gurabo, and San Juan). The global solar radiation data was measured by an Eppley Precision Spectral Pyranometer (model PSP) mounted on a horizontal surface. This pyranometer is sensitive to solar radiation in the range of 0.285 ≤ λ ≤ 2.8 μm wavelengths. Statistical analysis such as the daily average, monthly average hourly, monthly average daily, and annual average daily global radiation are presented in this paper. Despite its small size, a 13 percent variation in the global solar radiation has been observed within the island. Reasonable solar radiation values, for solar energy conversion system installation, seem to exist at and possibly around Aguadilla.

scholarly journals In-situ measurement of reactive hydrocarbons at Hohenpeissenberg with comprehensive gas chromatography (GCxGC-FID): use in estimating HO and NO<sub>3</sub>

2006 ◽  
Vol 6 (4) ◽  
pp. 8155-8188
Author(s):  
S. Bartenbach ◽  
J. Williams ◽  
C. Plass-Dülmer ◽  
H. Berresheim ◽  
J. Lelieveld
Keyword(s):  
Mean Value ◽  
Time Data ◽  
Night Time ◽  
Radical Species ◽  
Diurnal Cycles ◽  
Meteorological Observatory ◽  
Variate Analysis ◽  
The Relationship ◽  
Good Agreement

Abstract. During a field campaign at the Meteorological Observatory Hohenpeissenberg (MOHp) in July 2004, VOCs were measured using GCxGC-FID. Comparison to routinely made GC-MS measurements showed good agreement for a variety of anthropogenic and biogenic ambient VOCs ranging in concentration from below the detection limit (0.1 pmol mol−1) to 180 pmol mol−1. Pronounced diurnal cycles were found for both the biogenic and anthropogenic compounds, driven for the most part by the daily rise and fall of the boundary layer over the station. For the reactive compounds (lifetimes <2 days), a significant, non-zero dependency of the variability on lifetime was found, indicating that chemistry (as opposed to transport alone) was playing a role in determining the ambient VOC concentrations. The relationship was exploited using a single-variate analysis to derive a daytime mean value of HO (5.3±1.4×106 molecules cm−3), which compares well to that measured at the site, 3.2±2.3×106 molecules cm−3. The analysis was extended to the night time data to estimate concentrations for NO3 (1.47±0.2×108 molecules cm−3), which is not measured at the site. The feasibility of this approach for environments dominated by emissions of short-lived VOCs to estimate ambient levels of radical species is discussed.

The Exploitation of Variability and Noise in Micro Devices

2007 ◽  
Author(s):  
Kiyohisa Nishiyama ◽  
M. C. L. Ward
Keyword(s):  
Statistical Theory ◽  
Brownian Motion ◽  
Random Noise ◽  
Mean Value ◽  
Measurement Tool ◽  
Electronic Circuits ◽  
Johnson Noise ◽  
Micro Systems ◽  
Switch Group ◽  
Good Agreement

The strength of Micro Systems Technology (MST) is the ability to fabricate a large number of small devices economically. However such devices tend to have errors caused by the variations of fabrication and inherent noise signals such as Brownian motion or Johnson noise. This paper develops the understanding of Micro Switch Group Sensors (MSGS), which works by exploiting this random noise. In the experimental work reported here, an MSGS comprising of 20 switches has been built using electronic circuits and tested to verify the performance. The output of the device is simply the number of switches turned on, this is then transformed into the expected mean value of the input signal using standard statistical theory. The performance of the devices was shown to be in good agreement with the theoretical prediction. The linearity and the standard deviation of the output signal of MSGS are investigated and it is concluded that an MSGS may be successfully applied as a measurement tool.

scholarly journals An improved transmitter system to accurately measure wet-bulb temperature of air

2019 ◽  
Vol 52 (7-8) ◽  
pp. 1002-1007
Author(s):  
Liangwen Yan ◽  
Peng Yu ◽  
Sijung Hu ◽  
Qiu Gao ◽  
Wei Li ◽  
...  
Keyword(s):  
Real Time ◽  
Latent Heat ◽  
Measurement Accuracy ◽  
Cost Effective ◽  
Mean Value ◽  
Experimental Results ◽  
Iteration Algorithm ◽  
Good Consistency ◽  
The Mean ◽  
Good Agreement

A cost-effective measurement of wet-bulb temperature of air has great benefits to fulfill a growing demand of industry, cultivation agriculture, and medication. Applying an appropriate algorithm to wet-bulb temperature of air measurement can effectively improve the accuracy and speed of its measurement. The study aims to research how an improved transmitter system along with the latent heat–based iteration algorithm is used to precisely measure wet-bulb temperature of air. The work consists of (1) simulation of the iteration algorithm and (2) validation via experimental protocol. The simulation results through latent heat–based iteration algorithm were in good agreement ( R2≥ 0.99) with the reference. The performance of the improved wet-bulb temperature of air transmitter system was tested by a latent heat–based iteration algorithm experimental setup. The experimental results demonstrate that the improved wet-bulb temperature of air in a good consistency with commercial wet-bulb temperature of air in a range of temperature (15°C–34°C) and relative humidity (28.8%–76.2%). The Bland–Altman plot also shows that the mean value and the standard deviation of the differences between these two systems are 0.14°C and 0.29°C, respectively, which indicates that the improved wet-bulb temperature of air has a good agreement as well. Compared with the commercial wet-bulb temperature of air transmitter system, an advanced processor (STM32F103C8T6) and real-time operating system was applied in the improved wet-bulb temperature of air transmitter system. The experimental results show that its measurement accuracy is closer to the previous study. This study provides an alternative and cost-effective solution to accurately and real-time measure wet-bulb temperature of air.

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