Aim: To investigate the waiting times in the emergency department of both private and public hospitals. Methods: The study employs theoretical, qualitative, and quantitative approaches to come up with conclusions that...Aim: To investigate the waiting times in the emergency department of both private and public hospitals. Methods: The study employs theoretical, qualitative, and quantitative approaches to come up with conclusions that are reliable. A total of 473 participants who had a direct interaction with the emergency department were asked to provide data on the waiting time, the kind of hospital they went to, the symptoms they had, and their gender for evaluation purposes. Common symptoms identified to the patients visiting the emergency department are related to head and neck, chest, abdominal pains, genitals, limbs, and back. It was found that more patients visited public hospitals over private hospitals. Additionally, more patients had symptoms related to abdominal than any other of the common symptoms and more males than females participated in the research. Data recording is done in tables using MS Excel and data presented through analysis using bar graphs for comparative purposes. Conclusion: Based on the results of the research, it was concluded that the efficiency of the emergency department is below the recommended standards. Finally, the recommendations made from the research findings included an audit of the emergency departments, increasing the staff in the department, and more research should be conducted throughout the country to come up with a more reliable record that is more inclusive.展开更多
The current study was conducted primarily to investigate and estimate 137Cs activity concentrations and the external dose rate due to fallout radionuclide 137Cs. Soil samples were collected from different 25 locations...The current study was conducted primarily to investigate and estimate 137Cs activity concentrations and the external dose rate due to fallout radionuclide 137Cs. Soil samples were collected from different 25 locations at Riyadh Province and analyzed using low level γ-spectrometry equipped with HPGe-detector. 137Cs activity concentrations and calculated dose rate were found in the range of 0.8 - 3.1 Bq·kg–1 and 0.05 to 0.8 nSv·h–1 with an average value of 1.70 ± 0.7 Bq·kg–1 and 0.11 ± 0.05 nSv·h–1 respectively. The measured 137Cs activity concentration range was compared with the reported ranges in the literature from some of the other locations in the world. Results obtained in this study show that 137Cs concentration is of a lower level in the investigated area. However, the range of 137Cs concentrations observed in this study is significantly high relative to similar data reported from Libya. The average value of estimated external effective dose rate is found far below the dose rate limit of of 1.0 mSv·y–1 for members of the general public recom-mended by ICRP as well as the external gamma radiation dose of 0.48 mSv·y–1 received per head from the natural sources of radiation assessed by (UNSCEAR, 2000). It is concluded that 137Cs soil contamination does not pose radia-tion hazards to the population in the investigated areas.展开更多
Concentrations of airborne particulate matter (PM10 & PM2.5) were measured over a period extended from January 2012 to October 2013 at two sites: a suburban area, Riyadh airport (AP) and an urban area, King Fahd r...Concentrations of airborne particulate matter (PM10 & PM2.5) were measured over a period extended from January 2012 to October 2013 at two sites: a suburban area, Riyadh airport (AP) and an urban area, King Fahd road district (KF) (densely trafficked site) in Riyadh city, Saudi Arabia. The quality of ambient air using the U.S. Environmental Protection Agency (USEPA) Air Quality Index (AQI) was evaluated during this period. The average AQI values exceeded 100 on 6 months out of 11 in AP district. At KF district the condition was worse, and AQI values exceeded 100 on all months. This emphasizes the fact that PM concentrations over Riyadh can be regarded as a real environmental problem that could be a severe risk to quality of life and threaten human health. A higher-volume air sampler at the two sites was used to collect particulate matter (PM10 and PM2.5) for chemical analysis of the PM for PAHs and total organic carbon. At KF station the mean concentrations’ values of total PAHs in PM2.5 and PM10 were 4.89 ng/m<sup>3</sup> and 12.96 ng/m<sup>3</sup> respectively. At the AP station the corresponding values of total PAHs in PM2.5 and PM10 were 8.07 ng/m<sup>3</sup> and 11.91 ng/m<sup>3</sup> respectively. The PAHs did not exceed the air criteria of World Health Organization indicating the air pollution of PAHs in Riyadh District was not serious. As for the total organic carbon the results demonstrated that the concentration ranged from 0.211 to 0.506 g/kg at KF station and from 0.054 to 0.342 g/kg at AP station. On an annual basis, OC concentrations were two times higher for the city center site (KF) compared to the rural AP site. This can most likely be explained by increased emissions from higher traffic at KF site. The diurnal variability of PM was mainly associated with the severity of pollution.展开更多
Mass concentrations of PM10 and PM2.5 for January 2012 up to October 2013 were measured at two sites;a suburban area, Riyadh airport (AP) and an urban area, King Fahd road district (KF) (densely trafficked site). Dail...Mass concentrations of PM10 and PM2.5 for January 2012 up to October 2013 were measured at two sites;a suburban area, Riyadh airport (AP) and an urban area, King Fahd road district (KF) (densely trafficked site). Daily concentrations of both PM10 and PM2.5 measured at these two sites were highly variable. The temporal variation observed either for PM10 or PM2.5 was associated mainly with the dust events. The annual pattern of PM10 and PM2.5 at the AP station shows a significant increase in spring and summer (dusty seasons) where monthly mean concentrations of up to 696 μg·m-3 PM10 were recorded in March. PM10 concentrations during winter months are significantly lower, with 65 μg·m-3 measured in November and 78 μg·m-3 measured in December. January exhibits PM10 concentrations little above 100 μg·m-3. Both PM10 and PM2.5 showed substantial variations at these two monitoring stations during the study period. In the ur-ban station (King Fahd), average annual PM10 varied by up to roughly a factor of two. This variation implies that local emission sources in this site often contribute much (i.e. greater than half) of the PM10 mass on annual average. The variation of monthly (temporal) mean PM10 at KF station showed more or less similar results to the AP station. Higher concentrations were observed during spring and summer (12%, 17% and 13% in Feb., March and April respectively and 17, 15% during June and July). Starting from September and October, PM10 concentrations started to drop to 7% and 8% respectively. The relationships between the mean values of suspended particle concentrations and meteorological variables (relative humidity ambient temperature and wind speed) were analyzed. The results demonstrate that the influence of weather factors upon dust particulates is largely inconclusive. However, At KF station a moderate positive correlation was observed between wind speed and PM.展开更多
This study tests the southern part of the Riyadh City growth domination by the Early Quaternary-Holocene trans-tensional Central Arabian graben system reactivation and the subsequent dissolution-induced collapses and ...This study tests the southern part of the Riyadh City growth domination by the Early Quaternary-Holocene trans-tensional Central Arabian graben system reactivation and the subsequent dissolution-induced collapses and karstification. This study utilizes Synthetic Aperture Radar (SAR) and Differential Interfer</span><span style="font-family:Verdana;">ometric Synthetic Aperture Radar (DinSAR) to examine the mo</span><span style="font-family:Verdana;">rphology of arid landscape, south of Riyadh. Eight Single Look Complex (SLC) amplitude images are calibrated, filtered, georeferenced and orthorectified at a resolution of 20 meters, and compared with one another by producing 17 diachronic images of the pairs at different intervals (1996, 2003-2005, 2008). The diachronic SAR intensity imageries suggest a downthrown displacement reaching 600 m and eastward tilting at the bottoms of the grabens. Also, the structurally-controlled valleys are developing an eastward-running drainage system towards the oasis of Al-Kharj and capturing an older hydrologic system. Moreover, a 12-year period (1996-2008) of the SAR data was obtained to examine the average annual rate of southern Riyadh’s urban sprawl, which is estimated at approximately 390 metres/year over the 12 years and constrained by geomorphological features towards the deformed area. DInSAR imageries show the primary results obtained from the 26 May 2004 and 31 Jan. 2005 pair of images, merged with 30 m resolution DEM-SRTM data for the arid region south of Riyadh to eliminate the influence of topography. DInSAR is applied in this study for its ability </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">to </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">detect</span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">small displacements at the centimetre scale (1/2 wavelength). Although the DInSAR’s coherence and phase imageries suggest a fairly stable region since the last tectonic and subsequent geomorphic events, erosional and artificial changes are observed, bounded wit</span><span style="font-family:Verdana;">hin the valleys and depressions, primarily due to aeolian and fluv</span><span style="font-family:Verdana;">ial processes and agriculture. It is highly recommended to preserve the area for sustainability and economy.展开更多
People should be aware of sources of health hazards, such as radon gas;and efforts should be made to educate them. Radon awareness among people is important for monitoring its level in their residential houses to redu...People should be aware of sources of health hazards, such as radon gas;and efforts should be made to educate them. Radon awareness among people is important for monitoring its level in their residential houses to reduce the risk of ad-verse health effects. Furthermore, radon awareness among public would support and facilitate researchers working for such surveys during the field work. In the present study, a public survey was conducted to investigate radon awareness level among Saudi people in Riyadh. A questionnaire was designed and distributed among 2297 persons of various educational background. It was found that about 82% of the Saudi public in Riyadh were ignorant of radon and its associated health risks. It was also found that only ~18% of educated public knew about radon. It was concluded that Saudi public needs to be educated in this respect properly.展开更多
Traditional buildings, particularly residential dwellings, are spatio-temporal reflections of the society and culture in which they were originally sited. Understanding the nature of this built heritage thus fosters i...Traditional buildings, particularly residential dwellings, are spatio-temporal reflections of the society and culture in which they were originally sited. Understanding the nature of this built heritage thus fosters interpretation of previous generations’ experiences in these older settlements, all of which can thus be described as products of several different cultural dimensions. Qassim province, which sits in the central province of the Kingdom of Saudi Arabia, is distinguished by having retained various traditional towns and villages, including multiple dwellings representing important eras in the past. However, due to the local population’s abandonment of these traditional towns and movement to new urban areas, and related failures in conservation and restoration, some of these towns have lost many of their unique characteristics, especially with regard to their dwellings. This research thus attempts to interpret the relationships between the spatial configuration of traditional dwellings in Saudi Arabia and their socio-cultural principles and values, focusing on decoding their interior spatial constants and genotypes. The study proposes the use of space syntax theory, represented by the justified plan graph method, as an appropriate socio-spatial methodology for such work, targeting the traditional town of Riyadh Al-Khabra in Qassim province as a case study area, with eight dwellings built between 1900 and 1940 used as examples. Interpretation of analysis results enabled defining spatial constants digitally in these traditional dwellings through the benefit of syntactic analysis techniques, and the main findings of this research reveal the significance of various social and cultural factors and customs among inhabitants with regard to determining the spatial form and properties of traditional dwellings in towns such as Riyadh Al-Khabra.展开更多
The preparedness phase is considered as backbone of environmental disaster management. The aim of this study is to identify the effect of relatively constant factors of preparedness phase on environmental disaster man...The preparedness phase is considered as backbone of environmental disaster management. The aim of this study is to identify the effect of relatively constant factors of preparedness phase on environmental disaster management in Riyadh City, Saudi Arabia. The study used descriptive and analytical approach besides the comprehensive survey depends upon questionnaire for purposive data surveyed all employees in the field of environmental disaster management in Riyadh city including administrations, department, and contains 21 sector including public and private sector for total population of about 397 persons and sample size about 353 persons using statistical tests, frequencies, percentage, average, standard deviation and t test and × square test as well as Likert procedure on which depends on the measurement such as: very high, high, average, weak and very weak. The main results reveal that the constant factors of environmental disaster management are more important for evaluating the preparedness phase. Since the relatively constant factors of environmental disaster management are more important. The study recommends that: 1) Enhancement of the systems and procedures in particular disaster management procedures. 2) It is so necessary to publish a new unit for disaster management in the sectors have not. 3) Increase and encouragement of environmental disaster management studies in particular for preparedness phase because it considers as backbone of disaster management and suggestion of regional and local organizations link generally and in information trade off and the details studies in particular by providing the different types of support and encouragement.展开更多
The Riyadh metro project is one of the current megaprojects that aim to improve the transit systems in Saudi Arabia.It consists of several metro lines with a total length of 176 km and 85 stations.The viaducts are con...The Riyadh metro project is one of the current megaprojects that aim to improve the transit systems in Saudi Arabia.It consists of several metro lines with a total length of 176 km and 85 stations.The viaducts are considered as one of the main construction elements in the metro lines.Four methods for viaducts construction have been used in the Riyadh metro project:precast beam,full span launching method,cast on-site,and segment method(precast segment method and BCM(balanced cantilever method)).The viaducts work consumes a large portion of a project’s time and cost.Furthermore,the competitive nature of the construction industry increases the need to improve the efficiency of construction performance.Accordingly,this paper takes the initial steps toward increasing the efficiency of viaduct construction methods through simulation.Simulation of construction processes provides a systematic tool that can be used for determining the resources,time,and cost of these processes.The simulation processes should focus on the main activities affecting this element’s execution for viaducts construction,such as segment storage,handling,transporting,and installation.This study highlights the viaducts construction methods and develops general discrete-event simulation models for the most commonly used viaducts construction methods in the Riyadh metro using AnyLogic simulation software.The simulation models visualize and capture the interaction between the different activities and resources in a viaduct construction.Consequently,the construction drawbacks can be identified.Furthermore,the simulation model can be manipulated by adding assumptions to develop more efficient construction methods in terms of time and cost in such projects.展开更多
Much attention has been given to address public health policy in Saudi Arabia,particularly for the management,quality,and coverage issues.However,assessment of spatial patterns,distribution,and provision of public hea...Much attention has been given to address public health policy in Saudi Arabia,particularly for the management,quality,and coverage issues.However,assessment of spatial patterns,distribution,and provision of public health services has been neglected.This paper analyzes the availability and accessibility of public health facilities across Riyadh Governorate,Saudi Arabia at the subnational level.Spatial and attribute data of public health facilities potentially have been analyzed using GIS to produce accurate measure of accessibility.The spatial pattern of service distribution was examined using average nearest neighbor.Distances from demand points(populations)to providers(facilities)were calculated for each district using near analysis.In addition,the ratios of public health facility to population were calculated to identify underserved and overserved areas.The findings clearly indicate that the spatial pattern of the distribution of public health facilities was significantly clustered(p value<0.001)with Z-score of–10.9.Several districts within the central parts of the governorate were identified as having a higher density of facilities,while most of districts that are located in the marginal parts exhibit very low density of health facilities.Overall,there was a considerable variation in the average distance from district centroids to health facilities.Substantially,less than half of the population(45.4%)living in 61 districts has access to public health facility within less than 1-km distance.In contrast,the greatest increase in distances was observed for 6%of population living in 38 districts.People that live in such districts need to travel long distances for public health care.The output of this analysis can assist policy-makers and authorities of Riyadh Governorate in planning public health delivery.展开更多
This paper proposes a simple method of optimizing Air Quality Monitoring Network (AQMN) using Geographical Information System (GIS), interpolation techniques and historical data. Existing air quality stations are syst...This paper proposes a simple method of optimizing Air Quality Monitoring Network (AQMN) using Geographical Information System (GIS), interpolation techniques and historical data. Existing air quality stations are systematically eliminated and the missing data are filled in using the most appropriate interpolation technique. The interpolated data are then compared with the observed data. Pre-defined performance measures root mean square error (RMSE), mean absolute percentage error (MAPE) and correlation coefficient (r) were used to check the accuracy of the interpolated data. An algorithm was developed in GIS environment and the process was simulated for several sets of measurements conducted in different locations in Riyadh, Saudi Arabia. This methodology proves to be useful to the decision makers to find optimal numbers of stations that are needed without compromising the coverage of the concentrations across the study area.展开更多
CMAQ was implemented in the central region of Saudi Arabia and the effect of simulating models using various chemical mechanisms on selected oxidants, nitrogen species, and O3 was investigated. CB05TUCL predicted OH, ...CMAQ was implemented in the central region of Saudi Arabia and the effect of simulating models using various chemical mechanisms on selected oxidants, nitrogen species, and O3 was investigated. CB05TUCL predicted OH, MEPX, and NOz about 7%, 7.7%, and 8% more than CB05E51 respectively;however, there was no observable difference in the O3 predictions. The differences in variations of SAPRC07 mechanism (SAPRC07TB, SAPRC07TC, and SAPRC07TIC) for all parameters were less than 1%. RACM2 produced the highest OH and H2O2 concentrations. RACM2 enhanced OH production in the range of 24% - 32% and H2O2 by 9% over other mechanisms;these are comparatively less than the findings of other studies. Similarly, CB05 produced over 40% more PAN concentration than CB05. Moreover, PAN concentrations produced by all mechanisms were very high compared to other studies. SAPRC07 produced approximately 3% more mean surface O3 concentration than RACM2 and approximately 10% more than CB05. RACM2 O3 predictions were higher than CB05 by 7%. The predicted O3 concentrations by CB05, RACM2, and SAPRC07 were 6%, 11%, and 15% more than the average observed concentrations, which indicate that closest predictions to the observed values were by CB05. This study concludes that there is a wide variation of mechanisms with respect to the predictions of oxidants and nitrogen compounds;however, less variation is noticed in predictions of O3. For any air pollution control strategies and photochemical modeling studies in the current region or in any other arid regions, the CB05 mechanism is recommended.展开更多
Groundwater scarcity in arid regions may hinder development plans and cause many inconveniences for the population and authorities. Saudi Arabia has limited groundwater resources stored in the sedimentary sequence of ...Groundwater scarcity in arid regions may hinder development plans and cause many inconveniences for the population and authorities. Saudi Arabia has limited groundwater resources stored in the sedimentary sequence of the Arabian Shelf. Some of these resources were classified as major aquifers, secondary and minor aquifers, and some were considered as aquicludes. The Jubaila Limestone is one of the secondary aquifers of Saudi Arabia. The main purpose of this paper is to evaluate the groundwater resources of the Jubaila Limestone in Riyadh area, with emphasis on groundwater quality. Groundwater was found to occur in fractures and within solution openings of the Jubaila Limestone at depths which range between 19 and 210 m. The transmissivity value was 1.7 × 10–3 to 7.2 × 10–3 m2/s;the storage coefficient was of 1.3 × 10–4. The electrical conductivity for collected water samples ranged between 831 and 7670 μS/cm. The major ionic relationships were Na > Ca > Mg and SO4Cl > HCO3. The groundwater evolves from NaCl dominated at the southern end of the study area, into Ca, MgSO4 water in the north. The main chemical process responsible of this variation was found to be dissolution of anhydrite and gypsum. The groundwater was not found suitable for drinking purposes but can be used by livestock and for some agricultural purposes.展开更多
文摘Aim: To investigate the waiting times in the emergency department of both private and public hospitals. Methods: The study employs theoretical, qualitative, and quantitative approaches to come up with conclusions that are reliable. A total of 473 participants who had a direct interaction with the emergency department were asked to provide data on the waiting time, the kind of hospital they went to, the symptoms they had, and their gender for evaluation purposes. Common symptoms identified to the patients visiting the emergency department are related to head and neck, chest, abdominal pains, genitals, limbs, and back. It was found that more patients visited public hospitals over private hospitals. Additionally, more patients had symptoms related to abdominal than any other of the common symptoms and more males than females participated in the research. Data recording is done in tables using MS Excel and data presented through analysis using bar graphs for comparative purposes. Conclusion: Based on the results of the research, it was concluded that the efficiency of the emergency department is below the recommended standards. Finally, the recommendations made from the research findings included an audit of the emergency departments, increasing the staff in the department, and more research should be conducted throughout the country to come up with a more reliable record that is more inclusive.
文摘The current study was conducted primarily to investigate and estimate 137Cs activity concentrations and the external dose rate due to fallout radionuclide 137Cs. Soil samples were collected from different 25 locations at Riyadh Province and analyzed using low level γ-spectrometry equipped with HPGe-detector. 137Cs activity concentrations and calculated dose rate were found in the range of 0.8 - 3.1 Bq·kg–1 and 0.05 to 0.8 nSv·h–1 with an average value of 1.70 ± 0.7 Bq·kg–1 and 0.11 ± 0.05 nSv·h–1 respectively. The measured 137Cs activity concentration range was compared with the reported ranges in the literature from some of the other locations in the world. Results obtained in this study show that 137Cs concentration is of a lower level in the investigated area. However, the range of 137Cs concentrations observed in this study is significantly high relative to similar data reported from Libya. The average value of estimated external effective dose rate is found far below the dose rate limit of of 1.0 mSv·y–1 for members of the general public recom-mended by ICRP as well as the external gamma radiation dose of 0.48 mSv·y–1 received per head from the natural sources of radiation assessed by (UNSCEAR, 2000). It is concluded that 137Cs soil contamination does not pose radia-tion hazards to the population in the investigated areas.
文摘Concentrations of airborne particulate matter (PM10 & PM2.5) were measured over a period extended from January 2012 to October 2013 at two sites: a suburban area, Riyadh airport (AP) and an urban area, King Fahd road district (KF) (densely trafficked site) in Riyadh city, Saudi Arabia. The quality of ambient air using the U.S. Environmental Protection Agency (USEPA) Air Quality Index (AQI) was evaluated during this period. The average AQI values exceeded 100 on 6 months out of 11 in AP district. At KF district the condition was worse, and AQI values exceeded 100 on all months. This emphasizes the fact that PM concentrations over Riyadh can be regarded as a real environmental problem that could be a severe risk to quality of life and threaten human health. A higher-volume air sampler at the two sites was used to collect particulate matter (PM10 and PM2.5) for chemical analysis of the PM for PAHs and total organic carbon. At KF station the mean concentrations’ values of total PAHs in PM2.5 and PM10 were 4.89 ng/m<sup>3</sup> and 12.96 ng/m<sup>3</sup> respectively. At the AP station the corresponding values of total PAHs in PM2.5 and PM10 were 8.07 ng/m<sup>3</sup> and 11.91 ng/m<sup>3</sup> respectively. The PAHs did not exceed the air criteria of World Health Organization indicating the air pollution of PAHs in Riyadh District was not serious. As for the total organic carbon the results demonstrated that the concentration ranged from 0.211 to 0.506 g/kg at KF station and from 0.054 to 0.342 g/kg at AP station. On an annual basis, OC concentrations were two times higher for the city center site (KF) compared to the rural AP site. This can most likely be explained by increased emissions from higher traffic at KF site. The diurnal variability of PM was mainly associated with the severity of pollution.
文摘Mass concentrations of PM10 and PM2.5 for January 2012 up to October 2013 were measured at two sites;a suburban area, Riyadh airport (AP) and an urban area, King Fahd road district (KF) (densely trafficked site). Daily concentrations of both PM10 and PM2.5 measured at these two sites were highly variable. The temporal variation observed either for PM10 or PM2.5 was associated mainly with the dust events. The annual pattern of PM10 and PM2.5 at the AP station shows a significant increase in spring and summer (dusty seasons) where monthly mean concentrations of up to 696 μg·m-3 PM10 were recorded in March. PM10 concentrations during winter months are significantly lower, with 65 μg·m-3 measured in November and 78 μg·m-3 measured in December. January exhibits PM10 concentrations little above 100 μg·m-3. Both PM10 and PM2.5 showed substantial variations at these two monitoring stations during the study period. In the ur-ban station (King Fahd), average annual PM10 varied by up to roughly a factor of two. This variation implies that local emission sources in this site often contribute much (i.e. greater than half) of the PM10 mass on annual average. The variation of monthly (temporal) mean PM10 at KF station showed more or less similar results to the AP station. Higher concentrations were observed during spring and summer (12%, 17% and 13% in Feb., March and April respectively and 17, 15% during June and July). Starting from September and October, PM10 concentrations started to drop to 7% and 8% respectively. The relationships between the mean values of suspended particle concentrations and meteorological variables (relative humidity ambient temperature and wind speed) were analyzed. The results demonstrate that the influence of weather factors upon dust particulates is largely inconclusive. However, At KF station a moderate positive correlation was observed between wind speed and PM.
文摘This study tests the southern part of the Riyadh City growth domination by the Early Quaternary-Holocene trans-tensional Central Arabian graben system reactivation and the subsequent dissolution-induced collapses and karstification. This study utilizes Synthetic Aperture Radar (SAR) and Differential Interfer</span><span style="font-family:Verdana;">ometric Synthetic Aperture Radar (DinSAR) to examine the mo</span><span style="font-family:Verdana;">rphology of arid landscape, south of Riyadh. Eight Single Look Complex (SLC) amplitude images are calibrated, filtered, georeferenced and orthorectified at a resolution of 20 meters, and compared with one another by producing 17 diachronic images of the pairs at different intervals (1996, 2003-2005, 2008). The diachronic SAR intensity imageries suggest a downthrown displacement reaching 600 m and eastward tilting at the bottoms of the grabens. Also, the structurally-controlled valleys are developing an eastward-running drainage system towards the oasis of Al-Kharj and capturing an older hydrologic system. Moreover, a 12-year period (1996-2008) of the SAR data was obtained to examine the average annual rate of southern Riyadh’s urban sprawl, which is estimated at approximately 390 metres/year over the 12 years and constrained by geomorphological features towards the deformed area. DInSAR imageries show the primary results obtained from the 26 May 2004 and 31 Jan. 2005 pair of images, merged with 30 m resolution DEM-SRTM data for the arid region south of Riyadh to eliminate the influence of topography. DInSAR is applied in this study for its ability </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">to </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">detect</span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">small displacements at the centimetre scale (1/2 wavelength). Although the DInSAR’s coherence and phase imageries suggest a fairly stable region since the last tectonic and subsequent geomorphic events, erosional and artificial changes are observed, bounded wit</span><span style="font-family:Verdana;">hin the valleys and depressions, primarily due to aeolian and fluv</span><span style="font-family:Verdana;">ial processes and agriculture. It is highly recommended to preserve the area for sustainability and economy.
文摘People should be aware of sources of health hazards, such as radon gas;and efforts should be made to educate them. Radon awareness among people is important for monitoring its level in their residential houses to reduce the risk of ad-verse health effects. Furthermore, radon awareness among public would support and facilitate researchers working for such surveys during the field work. In the present study, a public survey was conducted to investigate radon awareness level among Saudi people in Riyadh. A questionnaire was designed and distributed among 2297 persons of various educational background. It was found that about 82% of the Saudi public in Riyadh were ignorant of radon and its associated health risks. It was also found that only ~18% of educated public knew about radon. It was concluded that Saudi public needs to be educated in this respect properly.
文摘Traditional buildings, particularly residential dwellings, are spatio-temporal reflections of the society and culture in which they were originally sited. Understanding the nature of this built heritage thus fosters interpretation of previous generations’ experiences in these older settlements, all of which can thus be described as products of several different cultural dimensions. Qassim province, which sits in the central province of the Kingdom of Saudi Arabia, is distinguished by having retained various traditional towns and villages, including multiple dwellings representing important eras in the past. However, due to the local population’s abandonment of these traditional towns and movement to new urban areas, and related failures in conservation and restoration, some of these towns have lost many of their unique characteristics, especially with regard to their dwellings. This research thus attempts to interpret the relationships between the spatial configuration of traditional dwellings in Saudi Arabia and their socio-cultural principles and values, focusing on decoding their interior spatial constants and genotypes. The study proposes the use of space syntax theory, represented by the justified plan graph method, as an appropriate socio-spatial methodology for such work, targeting the traditional town of Riyadh Al-Khabra in Qassim province as a case study area, with eight dwellings built between 1900 and 1940 used as examples. Interpretation of analysis results enabled defining spatial constants digitally in these traditional dwellings through the benefit of syntactic analysis techniques, and the main findings of this research reveal the significance of various social and cultural factors and customs among inhabitants with regard to determining the spatial form and properties of traditional dwellings in towns such as Riyadh Al-Khabra.
文摘The preparedness phase is considered as backbone of environmental disaster management. The aim of this study is to identify the effect of relatively constant factors of preparedness phase on environmental disaster management in Riyadh City, Saudi Arabia. The study used descriptive and analytical approach besides the comprehensive survey depends upon questionnaire for purposive data surveyed all employees in the field of environmental disaster management in Riyadh city including administrations, department, and contains 21 sector including public and private sector for total population of about 397 persons and sample size about 353 persons using statistical tests, frequencies, percentage, average, standard deviation and t test and × square test as well as Likert procedure on which depends on the measurement such as: very high, high, average, weak and very weak. The main results reveal that the constant factors of environmental disaster management are more important for evaluating the preparedness phase. Since the relatively constant factors of environmental disaster management are more important. The study recommends that: 1) Enhancement of the systems and procedures in particular disaster management procedures. 2) It is so necessary to publish a new unit for disaster management in the sectors have not. 3) Increase and encouragement of environmental disaster management studies in particular for preparedness phase because it considers as backbone of disaster management and suggestion of regional and local organizations link generally and in information trade off and the details studies in particular by providing the different types of support and encouragement.
文摘The Riyadh metro project is one of the current megaprojects that aim to improve the transit systems in Saudi Arabia.It consists of several metro lines with a total length of 176 km and 85 stations.The viaducts are considered as one of the main construction elements in the metro lines.Four methods for viaducts construction have been used in the Riyadh metro project:precast beam,full span launching method,cast on-site,and segment method(precast segment method and BCM(balanced cantilever method)).The viaducts work consumes a large portion of a project’s time and cost.Furthermore,the competitive nature of the construction industry increases the need to improve the efficiency of construction performance.Accordingly,this paper takes the initial steps toward increasing the efficiency of viaduct construction methods through simulation.Simulation of construction processes provides a systematic tool that can be used for determining the resources,time,and cost of these processes.The simulation processes should focus on the main activities affecting this element’s execution for viaducts construction,such as segment storage,handling,transporting,and installation.This study highlights the viaducts construction methods and develops general discrete-event simulation models for the most commonly used viaducts construction methods in the Riyadh metro using AnyLogic simulation software.The simulation models visualize and capture the interaction between the different activities and resources in a viaduct construction.Consequently,the construction drawbacks can be identified.Furthermore,the simulation model can be manipulated by adding assumptions to develop more efficient construction methods in terms of time and cost in such projects.
文摘Much attention has been given to address public health policy in Saudi Arabia,particularly for the management,quality,and coverage issues.However,assessment of spatial patterns,distribution,and provision of public health services has been neglected.This paper analyzes the availability and accessibility of public health facilities across Riyadh Governorate,Saudi Arabia at the subnational level.Spatial and attribute data of public health facilities potentially have been analyzed using GIS to produce accurate measure of accessibility.The spatial pattern of service distribution was examined using average nearest neighbor.Distances from demand points(populations)to providers(facilities)were calculated for each district using near analysis.In addition,the ratios of public health facility to population were calculated to identify underserved and overserved areas.The findings clearly indicate that the spatial pattern of the distribution of public health facilities was significantly clustered(p value<0.001)with Z-score of–10.9.Several districts within the central parts of the governorate were identified as having a higher density of facilities,while most of districts that are located in the marginal parts exhibit very low density of health facilities.Overall,there was a considerable variation in the average distance from district centroids to health facilities.Substantially,less than half of the population(45.4%)living in 61 districts has access to public health facility within less than 1-km distance.In contrast,the greatest increase in distances was observed for 6%of population living in 38 districts.People that live in such districts need to travel long distances for public health care.The output of this analysis can assist policy-makers and authorities of Riyadh Governorate in planning public health delivery.
文摘This paper proposes a simple method of optimizing Air Quality Monitoring Network (AQMN) using Geographical Information System (GIS), interpolation techniques and historical data. Existing air quality stations are systematically eliminated and the missing data are filled in using the most appropriate interpolation technique. The interpolated data are then compared with the observed data. Pre-defined performance measures root mean square error (RMSE), mean absolute percentage error (MAPE) and correlation coefficient (r) were used to check the accuracy of the interpolated data. An algorithm was developed in GIS environment and the process was simulated for several sets of measurements conducted in different locations in Riyadh, Saudi Arabia. This methodology proves to be useful to the decision makers to find optimal numbers of stations that are needed without compromising the coverage of the concentrations across the study area.
文摘CMAQ was implemented in the central region of Saudi Arabia and the effect of simulating models using various chemical mechanisms on selected oxidants, nitrogen species, and O3 was investigated. CB05TUCL predicted OH, MEPX, and NOz about 7%, 7.7%, and 8% more than CB05E51 respectively;however, there was no observable difference in the O3 predictions. The differences in variations of SAPRC07 mechanism (SAPRC07TB, SAPRC07TC, and SAPRC07TIC) for all parameters were less than 1%. RACM2 produced the highest OH and H2O2 concentrations. RACM2 enhanced OH production in the range of 24% - 32% and H2O2 by 9% over other mechanisms;these are comparatively less than the findings of other studies. Similarly, CB05 produced over 40% more PAN concentration than CB05. Moreover, PAN concentrations produced by all mechanisms were very high compared to other studies. SAPRC07 produced approximately 3% more mean surface O3 concentration than RACM2 and approximately 10% more than CB05. RACM2 O3 predictions were higher than CB05 by 7%. The predicted O3 concentrations by CB05, RACM2, and SAPRC07 were 6%, 11%, and 15% more than the average observed concentrations, which indicate that closest predictions to the observed values were by CB05. This study concludes that there is a wide variation of mechanisms with respect to the predictions of oxidants and nitrogen compounds;however, less variation is noticed in predictions of O3. For any air pollution control strategies and photochemical modeling studies in the current region or in any other arid regions, the CB05 mechanism is recommended.
文摘Groundwater scarcity in arid regions may hinder development plans and cause many inconveniences for the population and authorities. Saudi Arabia has limited groundwater resources stored in the sedimentary sequence of the Arabian Shelf. Some of these resources were classified as major aquifers, secondary and minor aquifers, and some were considered as aquicludes. The Jubaila Limestone is one of the secondary aquifers of Saudi Arabia. The main purpose of this paper is to evaluate the groundwater resources of the Jubaila Limestone in Riyadh area, with emphasis on groundwater quality. Groundwater was found to occur in fractures and within solution openings of the Jubaila Limestone at depths which range between 19 and 210 m. The transmissivity value was 1.7 × 10–3 to 7.2 × 10–3 m2/s;the storage coefficient was of 1.3 × 10–4. The electrical conductivity for collected water samples ranged between 831 and 7670 μS/cm. The major ionic relationships were Na > Ca > Mg and SO4Cl > HCO3. The groundwater evolves from NaCl dominated at the southern end of the study area, into Ca, MgSO4 water in the north. The main chemical process responsible of this variation was found to be dissolution of anhydrite and gypsum. The groundwater was not found suitable for drinking purposes but can be used by livestock and for some agricultural purposes.
