沙烏地阿拉伯

The last two decades have seen 60% annual growth rate (AGR) in the global IP traffic and it is expected that the AGR will keep the exponential growth in the next five years. Recent advances in digital signal processing enabled the implementation of the dual polarization (DP) optical coherent digital receivers, which substantially improved their performance. The goal of this research is to develop a prototype of a compact superchannel flexible DP M-ary quadrature amplitude modulation (MQAM) optical transmitter and demonstrate its reconfigurability to accommodate baud rates ranging from 8-32 Gbaud∕s to achieve 1 Tb/s and beyond using the same hardware. The research work consists of three phases; Phase I is the study of transmitter electrical and optical parts; Phase II investigates the potential configurations for frequency comb generator circuit; Phase III deals with the superchannel experimental prototype. The results obtained so far are pertaining to phase I and phase II with some preliminary experimental validation pertaining to phase III. The experimental results show that the measured component characteristics are matched with the components specifications data sheets. Additionally, the designed frequency comb generator was able to create up to 9 optical subcarriers with flat gain of 0.5 dB amplitude. Transmission over optical subcarriers has been attempted using standard optical transmitter. These results show promise towards the generation of a variable data rate up to 1Tb∕s. IEEE and ITU-T standardization effort considered these data rates to appear around 2017, and are intended for Next Generation Regional/Long-haul Networks.

The study aims to evaluate the technique of extracting water from humid air using solar energy through greenhouses in local areas. This technique is believed to provide limited amount of water in areas where potable water is not accessible or abundant. To solve this problem a pyramid-shaped device was designed, it is made of glass panels ad equipped with glass doors, fans operated by solar energy, and multiple shelves covered with fabric to act as Absorbent Calcium Chloride (CaCl2) with a 30% concentration. The doors are open during the night for absorption and closed during the day for energy-generating. Humidity, temperature, and atmospheric pressure are measured every two hours. The amount of water extracted in this area in one full day was around 3.0 liters a day for every square meter. Perhaps the limited amount of water is due to low level of humidity in the area: an average of 50% and temperature of F10 Celsius at night. However, the device itself is independent, does not need power sources, water sources, or infrastructure, can be installed in various places depending on humidity level as well as having the possibility of increasing number or size of device. This makes the device a promising, alternative and environmental friendly solution to produce water. Cost-effective and lighter material can be used to make the device, which will produce an easy-to-use and affordable devices. It is an area in need for further research to improve and further develop it.

Solar energy is a main source of energy that is expected to play a vital role in fulfilling the future global demand of electricity. Design of advanced photovoltaic (PV) system with high electric conversion efficiency is the key for collecting solar energy. A major obstacle hindering useful PV utilization is the deterioration of solar cell efficiency with temperature. The present results of experimentation have shown that there occurs a reduction of approximately 33% in the solar panel efficiency as the operating temperature increases from 45 °C to 68 °C at 1000 W/m2. Therefore, an innovative design of enhanced-performance solar panel using micro flat heat pipe (HP) and thermoelectric generator (TEG) is proposed and experimentally investigated in the presented project. To operate HP and TEG at highest possible efficiency, the condensation section of HP is innovatively cooled by utilize the condensed water inside the evaporator of air conditioner (which is usually between 5-7 °C). Two different types of silicon panel are used in the study: monocrystalline solar panel and polycrystalline solar panel. The results showed that a reduction in average solar panel temperature up to 25% is obtained. In addition, produced power was increased by as much as 50% when solar panel was cooled by the heat pipe. Finally, the feasibility study and cost analysis of the proposed hybrid system are discussed in details and presented.

CNC machines use vector graphics or vector image programs that take time and effort on hobbyists. Therefore, it is important to provide accurate techniques for converting ordinary images available on the Internet or can be designed with easy programs. In order to have precise drill paths read by CNC machines directly and produce a product that does not contain rattles at the edges. This depends on the accuracy of processing the extracted paths. The development of algorithms has been completed Transforms Pixel image into Paths with XYZ extension, which is used to drill material and cut it through CNC machines. And the algorithms are based on transfer images with low quality. And Its Advantage that it can create high Paths with as few points as possible. The program can convert the pixel image into paths, and then converted into g-code, and use it in CNC machines directly.

Visual impairment is a major global health problem. In 2017, WHO estimated that there were 253 million people worldwide with this ailment. According to the journal of the American Medical association, the prevalence of visual impairment in the Saudi population is 9.3%. Learning Braille by families of students with visual impairments remains a major obstacle, which precipitates several communication issues. Moreover, difficulties for the students themselves lie in learning braille with languages that include diacritical marks; consequently, affecting their academic progress. My main objective of this project is to help improving life quality of these individuals, and the focus is to advance their social productivity and adaptation. This was accomplished through creating a new simpler Arabic writing system using geometrical shapes. As a part of this project, fifteen participants with visual impairments were interviewed and tried this new writing system; two of them are adults between 25 and 40 years old while the rest are students from 9 to 17 years old. Additionally, 100 participants with visual impairments completed a survey. The data showed that students learned this system in two hours in comparison with students that mastered braille in a few months. This shows that this system is easier to learn and subsequently saves time and effort. The most important value added to this project is that diacritical marks were combined with the alphabet, thereby considerably reducing book sizes compared to Braille-written books. This project presents a novel system that helps people with visual impairments to increase their confidence and independence.

Water treatment is considered as one of the top research priorities in Saudi Arabia. It has been reported by World Health Organization that, 50,000 people die every day from diseases caused by contaminated water. This research attempts to degrade organic pollutants present in wastewater by using Graphene Oxide synthesized from Saudi natural source. Physical activation of date pits was carried out by carbonizing the samples at different temperatures to produce active carbon. Hammer’s method was employed for the purpose of Graphene Oxide production. The resulted Graphene Oxide has been characterized using FT-Raman, XRD and SEM techniques. Methylene Blue (MB) dye was used as a model organic pollutants to examine the ability of Graphene with the aid of a microwave-system to remove such pollutants. A modified domestic MS furnace with a variable power was used to supply microwave energy. The MB solution 2.5x10-6M was mixed with 0.1gm of Graphene Oxide. The applied microwave power was ranged between 100 to 700 W and the time was set between 0 to 12 minutes. The samples were centrifuged and then filtered through a millipore filter to remove the Graphene Oxide dispersed particles. It is found that, 98% of the initial concentration of MB is removed effectively within 12 minutes under microwave power of 500 W. Chemical oxygen demand is shifted from 450 to 87 mg/L while biological oxygen demand was decreased from 270 to 12.8 mg/L which indicating the degradation of organic constituents. This method can be used for water purification from organic pollutants.

In the upcoming years, both population and energy consumption are expected to increase dramatically [1]. Industrialization has led to a dramatic shift in the energy environment [2], with predictions of a 57% increase in demand for energy between 2002 and 2025 [3]. In addition to organic materials like trees and solid waste, fossil fuels like coal, natural gas, and oil provide more than 90% of the world's energy needs. Their overuse has resulted in the release of climate-altering greenhouse gases like carbon dioxide (CO2) and methane (CH4) into the atmosphere [4]. Scientists and other stakeholders are putting more emphasis on finding solutions to global warming, increasing energy production in order to meet increasing demands, and decreasing emissions of greenhouse gases. Using greenhouse gasses to make useful chemicals or fuels is one solution to both problems [5]. This motivated researchers to investigate the potential of CO2 and CH4 as clean energy sources. The process of dry reforming of methane (DRM) has been identified as a potentially successful strategy for transforming CO2 into marketable syngas with a balanced H2/CO composition [6], [7], [8], [9]. The economic viability of DRM, the reactor type, the availability of raw materials, and the intended use of the produced syngas are all-important considerations. Though DRM is gaining popularity, maintaining its long-term stability is difficult due to carbon accumulation from CO disproportionation and methane degradation [10], [11]. The catalyst used, as well as other parameters like as pressure, temperature, feed concentration, and reactor size, are critical to the process's effectiveness. In this scenario, a nickel catalyst on a La2O3/SiO2 substrate with microspheres and a core-shell structure will be developed to improve the conversion of greenhouse gases into profitable syngas. This catalyst is projected to improve the efficiency and performance of the DRM process significantly.

Energy has had an enormous impact on the development of technology and is a main factor in humans’ advancement towards an evolved society. Nevertheless, nonrenewable energy resources – which are the most effective in everyday application - have led to changes in the climate, environment, human health, and the world in general [1], which has encouraged researchers to switch to the use of renewable energy sources. Solar Cells are one of the most effective resources that rely on renewable energy. They come in a variety of types, operation methods, and efficiency as shown in Figure 1, including Dye-Sensitized Solar Cells (DSSC), which, inspired by photosynthesis in plants, uses photo-sensitive dye to capture sunlight and generate electricity. DSSCs were proved to have generated a great deal of interest and are one of the most promising solar cells among third-generation PV technologies, due to their low cost, simple preparation, good performance, and environmental friendliness compared to conventional photovoltaic devices [3]. However, their efficiency is quite insufficient for everyday use. Previous studies proved that Tandem DSSCs – which are two dye-sensitized cells stacked on top of each other – are able to enhance cell performance. The light absorption range of a tandem cell is increased because the bottom cell behind the top one absorbs and uses the incident light that was not absorbed by it [4]. It operates as shown in Figure 2, where the light photons excite the electrons of the dye molecules. The electrons are then transported to the FTO (conductive glass) by the semiconductor, which is used in the figure as TiO2 nanoparticles. The electrons pass through the circuit to perform the work, then move to the counter electrode (shown as Platinum). They are then transported by the electrolyte (I-/I3-) back to the dye molecules, and the process is repeated.

Nano additives is becoming popular trends nowadays due to its nanosize (1-100 nm). Incorporating nano additives in polymer could increase different properties such as mechanical, physical, electrical and thermal stability (1, 2). Different nano additives has been used such as nano copper oxide, nano silica, nano zinc oxide, nano titanium dioxide but most of these come from synthetic or metal oxides that considered as non-environmentally friendly and harmful to human when exposed or inhaled (3). One of the green materials that become attention by researchers is nano cellulose. Nano cellulose can be extracted in different methods and sources such as from wood, and non-woody resources such as kenaf, jute, bamboo as well as from bacteria such as Acetobacter species(4). This making nano cellulose abundantly available in resources. Nano cellulose can be in the form of nano crystalline cellulose (CNC) or NCC or can be in form of nano fibrillated cellulose (NFC) and bacterial nanocellulose (BNC)(5). This nanocellulose has many advantages that can give improvement in different applications such as mechanical, physical, thermal and improving the biodegradation when added together in different matrices (6, 7). Polymers have a problem in thermal stability while processing. It hard to control and maintain the thermal stability of polymer during processing and most polymers considered to have low in thermal stability except for thermosetting polymers such as epoxy. Epoxy has been widely used in many fields such as coating, adhesive, laminates, castings and many more (8). But the drawbacks of epoxy while using is hard to maintain and controll the thermal properties when processing of this materials and used for long period due to aging and attack by free radicals causing by UV radiation (9, 10). In this study we are incorporating nano additives into epoxy as polymer matrix to enhance and improve the thermal stability of composite by crosslinking the polymer chains with the nano additives. Furthermore, the nano additive used is come from nano cellulose extracted from date palm waste and thus to create an environmentally friendly and sustainable nano additives products.

Carbon dioxide (CO2) is an important greenhouse gas that helps trap heat in our atmosphere; without it, our planet would be inhospitably cold [1]. It is the fourth most abundant gas in the Earth's atmosphere. It is a byproduct of normal cell function when breathed out of the body, and produced when fossil fuels and organic wood compounds are burned [2]. However, an increase in CO2 concentration in the atmosphere can contribute to climate change and ocean acidification, and exposure to high levels of CO2 can produce a variety of health effects [3]. Human progress and economic innovation have led to increased emissions, causing climate change and affecting all living creatures. Current levels are 36.8 Gt CO2 in 2023 and are expected to reach 54-56 Gt CO2 by 2030 [4]. Figure 1 displays the current atmospheric CO2 measurements at Mauna Loa Observatory without seasonal variations [5].