121 research outputs found
Comparative Analysis Between Saudi Arabia and Norway in Moving Beyond Fossil Fuels Towards a Sustainable Economy: A Special Emphasis on the Renewable Energy Sector
Saudi Arabia is the largest economy in the Middle East and the 18th largest in the world. The country has the world\u27s second-largest proven petroleum reserves and is the largest exporter of petroleum. In 2016, Saudi Arabia had the third highest estimated value of natural resources at $34.4 trillion (US). However, because of the 2014 oil crash, climate change, and the development of renewable energy technology, the government has decided to transition from its complete reliance on oil revenues and to start investing heavily in other non-oil sectors, such as the renewable energy sector. The Saudi government plans to generate 30% of its electricity from renewable energy sources and to establish a sustainable competitive market system. The country has planned to make this enormous shift with the help of the McKinsey Global Institute and the plan titled “Saudi Arabia Beyond Oil: The Investment and Productivity Transformation,” which is also known as “the vision of 2030.”
Saudi Arabia and Norway are similar countries as they are both oil producers. Norway is a leading country in terms of creating a sustainable economy that generates electricity mostly from renewable energy, while Saudi Arabia has recently decided to shift away from fossil fuels and to focus on non-oil sectors, such as the renewable energy sector. Thus, this thesis will provide a comparative study between Saudi Arabia and Norway. This analysis will benefit Saudi Arabia with the Norwegian success in shifting from its reliance on fossil fuels to other non-oil sectors, mainly the renewable energy sector. The thesis will address the challenges that Saudi Arabia may encounter in achieving its goals related to the 2030 vision of shifting toward a sustainable economy and will offer some recommendations to facilitate achieving these goals
Optical properties Of CAD-CAM lithium disilicate glass-ceramic in different firing temperatures and thicknesses
Indiana University-Purdue University Indianapolis (IUPUI), Indiana University School of DentistryBackground: With the emerging of digital dentistry, IPS e.max® CAD lithium disilicate (LD) glass-ceramic material has become one of the most popular esthetic restorative materials in digital assisted dental esthetic restoration. The mechanical and optical properties of this material have been investigated in several studies. However, there is a lack of information and consensus regarding the optical properties of IPS e.max® LD glass-ceramic materials.
Objectives: 1) To investigate the optical properties as translucency parameters (TP), Contrast ratio (CR), light transmissions (Lt) and color changes (CC) between high-translucent (HT) and low-translucent (LT) IPS e.max® CAD LD glass-ceramic materials with different crystalline phases and thickness in different firing stages. 2) To investigate the optical properties as TP, CR, Lt and CC of each translucent (HT and LT) IPS e.max® CAD LD glass-ceramic materials with different crystalline phases and thickness in different firing stages. 3) To determine the mathematical relationships of thicknesses of IPS e.max® CAD LD glass-ceramics materials with TP and Lt. Materials and methods: The total of 120 of shade A2 IPS max CAD samples (HT and LT) were prepared into square shape (15.25 mm X 15.25 mm) and were divided into two main groups according to the material translucency (HT and LT) (n=60). Each main group was further divided into 5 sub-groups according to the thickness (1.00, 1.25, 1.5, 1.75, and 2.00 mm) (n=12). Each thickness group was assigned into three groups based on different crystallization (firing) temperatures (750, 820 °C in single stage heating schedule with 1 second and 10 second holding times, respectively, and 840 °C with two-stage heating schedule (RECOM) (820°C, 840 °C with 10 second and 7 min holding time, respectively) as recommended by manufacturer (n=4). CIEL*a*b*, TP, CR, and Lt were measured and calculated for all samples.
Statistical analysis: The effects of the test results were evaluated using 3-way ANOVA with factors for Translucency (HT and LT), Firing Temperature (750, 850, and RECOM) and Thickness (1, 1.25, 1.5, 1.75, and 2), as well as all two-way and three-way interactions among the factors. Pair-wise comparisons were made using Least Significant Differences to control the overall significance level at 5%.
Results: The mean irradiance and TP for both HT and LT decrease as the thickness of the samples increases from 1 to 2mm with significant difference between the thickness groups within each material translucency groups (HT and LT) and between both HT and LT. The coefficients of absorption (c) of the two materials were calculated. The effective incidence irradiance when material thickness approaches zero (Ie) was also calculated. There is an unexpected spectral peak shift as the thickness of the samples increases. There is no statistically significant difference in Ie at 750ËšC and 820 ËšC between the HT and LT. However, there is a statistically significant higher Ie in HT at the recommended firing temperature as expected. Coefficients of translucency parameter (p) of the materials in various firing temperature were defined and the TP of the material as the thickness approaches zero were calculated (TP0). The TP of the materials is directly correlated to the mean irradiance passing through the samples. There is no statistically significant difference in the TP0 and Ie of the HT and LT groups at the recommended firing temperature.
Conclusion: In this project we developed modified Beer-Lambert law to describe the parameters governing the effect of thickness on light transmission in dental ceramic material. We also applied the same equation to describe the translucency parameter. The parameters defined in these equations allow us to compare the optical property of dental ceramic material independent of the thickness of the samples
Nonextensive hydrodynamics of boost-invariant plasmas
We use quasiparticle anisotropic hydrodynamics to study the non-conformal and
non-extensive dynamics of a system undergoing boost-invariant Bjorken
expansion. To introduce nonextensivity, we use an underlying Tsallis
distribution with a time-dependent nonextensivity parameter . By taking
moments of the quasiparticle Boltzmann equation in the relaxation-time
approximation, we obtain dynamical equations which allow us to determine the
time evolution of all microscopic parameters including . We compare
numerical solutions for bulk observables obtained using the nonextensive
evolution with results obtained using quasiparticle anisotropic hydrodynamics
with a Boltzmann distribution function (). We show that the
evolution of the temperature, pressure ratio, and scaled energy density, are
quite insensitive to which distribution function is assumed. However, we find
significant differences in the early-time evolution of the bulk pressure which
are observed for even small deviations from the Boltzmann distribution
function. Finally, we discuss the existence of non-conformal hydrodynamic
attractors for the longitudinal and transverse pressures, the bulk and shear
viscous corrections, and the nonextensivity parameter .Comment: 24 pages, 5 multipanel figure
Favor Asking in Saudi Arabic
This study investigated the speech act of asking for a favor in Saudi Arabic, in terms of both core strategy and modification. It examined whether degree of imposition, social distance, and power have an influence on the shape of the act. It also compared and contrasted favor asking in Saudi Arabic, Kuwaiti Arabic, and American English. Data were collected using a written discourse completion test (DCT) in which 60 female native speakers of Saudi Arabic were asked to request a favor in 12 situations that varied the degree of imposition, social distance, and power. The findings revealed that favor asking was mostly direct and conventionally indirect in Saudi Arabic, although the participants slightly preferred more direct strategies. Nonconventional favor asking (i.e., hinting) was strongly disliked by the participants. It was found that core strategy use in favor asking in Saudi Arabic was significantly influenced by degree of imposition and social power, but not by social distance. Modification use was significantly influenced by degree of imposition, social distance, and social power. Favor asking in Saudi Arabic was found to be more similar to that in Kuwaiti Arabic than that in American English.Englis
Shilajit elicits apoptosis and suppresses cell migration in oral cancer cells through targeting Urokinase-type plasminogen activator (uPA) and its receptor (uPAR) and chemokine signaling pathways
Shilajit (Mumio) is a humic substance with a dark brown colour that comes from rocks found at high altitudes. For centuries, shilajit has been a widely employed traditional medicinal remedy to address various physical ailments. Given the prevalence of oral cancer, there is a growing need for more effective therapies in its treatment.
In this in vitro study, the impact of shilajit on normal human gingival fibroblast cells (hGFs) and oral cancer cells (KB-1, subline of the KERATIN-forming tumor cell line HeLa) was compared. The MTT and Annexin-V tests were used to measure the KB-1 cells growth and apoptosis after they were exposed to varying concentrations of Shilajit for 24h. An inverted microscope was used to evaluate the shilajit treated cell morphology. On the other hand, AO/EtBr dual staining was employed to analyse cellular apoptosis quantitatively. ROS production analysis was carried out utilizing DCFH-DA staining, while the gene expression of proapoptotic and antiapoptotic proteins was assessed through real-time PCR
Role of Mumio in periodontal wound healing–an in vitro study on human PDL cells
Mumio, used in ancient medicine for almost 4000 years, is the gold standard of traditional medicine. Mumio, a tar-like compound made from rock dissolved minerals and degraded organic matter, takes a century to form. Dibenzo-alpha-pyrones, humic acid, and fulvic acid are important in Mumio, which includes 60–80% humus, benzoic acid, fatty acids, ichthyol, ellagic acid, resin, triterpenes, sterol, aromatic carboxylic acids, bioactive 3,4-benzokoumarins, amino acids, phenol Active chemicals improve Mumio\u27s antioxidant effects. Despite its anti-ulcerogenic, anti-inflammatory, antioxidant, immunomodulatory, memory-enhancing, and anxiolytic characteristics, mumio has been studied rarely on oral tissues. The present study examined the cytotoxic, antioxidant, anti-inflammatory, and reparative effects of the aqueous fraction of Mumio on primary cultures of human periodontal ligament (PDL) fibroblasts
Assessment of rooftop solar power generation to meet residential loads in the city of Neom, Saudi Arabia
The economic and social development of the Kingdom of Saudi Arabia (KSA) has led to a rapid increase in the consumption of electricity, with the residential sector consuming approximately 50% of total electricity production. The KSA depends largely on non-renewable energy resources, and the government has produced Saudi Vision 2030. This plan aims to lessen the country’s reliance on fossil fuels and reduce associated problems such as air pollution. Saudi Vision 2030 combines renewable energy and new building designs so that, for example, the planned city of Neom will be net zero energy. This study addresses how best to reduce Neom’s reliance on the national grid through rooftop photovoltaic generation in residential buildings. The study develops a techno-economic model of rooftop PV with battery storage suitable for existing residential building types likely to be built in Neom city (villas, traditional houses, and apartments), and assesses the optimal PV size, battery storage capacity, and optimal orientation of the PV panels. The study used HOMER Pro to compute the Net Present Cost, Levelized Cost of Energy, orientation of PV panels, and optimum PV system size. The optimal size of PV system is 14.0 kW for the villa, 11.1 kW for the traditional dwelling, and 10.3 kW for the apartment, each with a single battery of capacity 12 kWh
Analysis of Total Lip Score System and Total Groove Score for gender identification: A cross sectional study
Endless ink and pixel space have been spent to validate the use of cheiloscopy classification systems in the field of identification. It is becoming evident that lip-print patterns may provide indications about an individual\u27s gender, race, occupation, habits, blood type, and paternity. Over the course of time, much data has been collected on a substantial population in this field. In the present study, we strive to see how well a noble total lip scoring system (TLS) works in identifying a person\u27s gender among College of Dentistry students. We also quantified the total groove score (TGS) and compared it with each quadrant for better authentication of the set study design
Methods of Protection Against the Attraction and Recruitment of Terrorist Groups Through Social Media
This study aimed to identify the methods that can be used to protect Saudi women from being attracted and recruited by terrorist groups through social media from teaching staff members in Saudi universities. The study used an analytical descriptive methodology to collect data using questionnaires from 382 teaching staff members in Saudi universities. Findings revealed that entertainment, filling leisure time and the desire to know the news were the most dominant motivations among Saudi women for using social media websites. Moreover, the ability to access Saudi women and offer the ideas to them by various and attractive methods, and differentiating by interactive property were the methods used by terrorist groups for attracting and recruiting Saudi women. The study therefore, recommend to develop a comprehensive national strategy aimed at limiting the ability of terrorist groups and organizations to employ digital media in general and social media, especially in attracting and recruiting Saudi nationals
Recycling Single Use Plastics to Useful Chemical Intermediates
Polymers are extremely stable and with rising landfill costs, forthcoming extended producer responsibility tax and the drive towards a circular economy, there is an increasing need to redirect polymer waste from landfill/energy recovery towards enhanced recovery of the raw materials/feedstocks. The COVID pandemic has introduced a significant amount of personal protective equipment (PPE) single use plastics in the form of facemasks into our global ecosystem, which is increasingly becoming an environmental issue due to their increasing non-biodegradability and with declining landfill capacity, this makes plastic recycling a necessity. Chemical recycling stands out as a viable method of converting plastic waste into valuable products, especially liquid fuels (naphtha) and liquefied petroleum gas (LPG). Chemical recycling of plastics can also serve as a route to introduce circularity into the plastic supply chain. This research study is focused on investigating the use of heterogeneous catalysts (zeolites Beta and USY) for the conversion of polypropylene (PP) and single use facemasks into chemical feedstock using hydrocracking. Catalytic hydrocracking reactions were carried out between 270-330 °C at 20 bar hydrogen pressure for 30-60 minutes. The results indicates that USY zeolite was more effective than zeolite beta due to its higher selectivity to liquid products. Moreover, the presence of highly acidic catalysts can be used to suitably recycle polymers into useful hydrocarbons with C3-C16 product distributions
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