Analyzing and forecasting COVID-19 pandemic in the Kingdom of Saudi Arabia using ARIMA and SIR models.

The novel coronavirus COVID-19 is spreading all across the globe. By June 29, 2020, the World Health Organization announced that the number of cases worldwide had reached 9 994 206 and resulted in more than 499 024 deaths. The earliest case of COVID-19 in the Kingdom of Saudi Arabia (KSA) was registered on March 2 in 2020. Since then, the number of infections as per the outcome of the tests increased gradually on a daily basis. The KSA has 182 493 cases, with 124 755 recoveries and 1551 deaths on June 29, 2020. There have been significant efforts to develop models that forecast the risks, parameters, and impacts of this epidemic. These models can aid in controlling and preventing the outbreak of these infections. In this regard, this article details the extent to which the infection cases, prevalence, and recovery rate of this pandemic are in the country and the predictions that can be made using the past and current data. The well-known classical SIR model was applied to predict the highest number of cases that may be realized and the flattening of the curve afterward. On the other hand, the ARIMA model was used to predict the prevalence cases. Results of the SIR model indicate that the repatriation plan reduced the estimated reproduction number. The results further affirm that the containment technique used by Saudi Arabia to curb the spread of the disease was efficient. Moreover, using the results, close interaction between people, despite the current measures remains a great risk factor to the spread of the disease. This may force the government to take even more stringent measures. By validating the performance of the applied models, ARIMA proved to be a good forecasting method from current data. The past data and the forecasted data, as per the ARIMA model provided high correlation, showing that there were minimum errors.

Experimental Investigation of Fabricated Graphene Nanoplates/Polystyrene Nanofibrous Membrane for DCMD.

In recent decades, the fabrication of composite membranes using nanoparticles has played a vital role in membrane distillation (MD) technique. It could make available membranes with superior characteristics as excellent candidates for MD technique. The most well-known obstacles regarding the MD method are the low productivity and high cost. Thus, fabricating membranes with superior properties is a significant challenge. In the current study, a composite membrane has been fabricated using 0.25, 0.5, and 0.75 weight percent (wt.%) of graphene nanoparticles (GNPs) with polystyrene (PS) as a base polymer and characterized using SEM, FTIR, and contact angle. The characterization results prove the successful fabrication using electrospinning and the validity of the fabricated membranes to be applied to direct contact membrane distillation (DCMD). In addition, a DCMD experimental setup has been designed to examine the performance of the fabricated membranes and compare the performance of blank PS with composite PS/GNPs membranes. The results show that all fabricated membranes produced an approximately similar average flux of about 10 kg/m2 h, while the highest GNPs wt.% showed the highest salt rejection. Accordingly, this composite membrane has been examined at different operating parameters and showed stable performance. Moreover, feed temperature and the rate of flow have a positive impact on the overall performance of the DCMD.

Modeling and Simulation of Fabricated Graphene Nanoplates/Polystyrene Nanofibrous Membrane for DCMD.

Membrane distillation is an active technique that provides pure water with very good rejection and could be applied to water of extremely high salinity. The low productivity of membrane distillation needs intensive efforts to be competitive with other desalination techniques. In this current study, a composite (PS/GNP) membrane, which is composed of polystyrene (PS) based and 0.25% weight percent graphene nanoplates (GNP) has been fabricated via electrospinning and compared with the blank PS membrane. SEM, FTIR, contact angle and porosity characterization have been performed, and the results show that the validity of the predefined conditions, and the contact angle of the composite membrane, which is found to be 91.68°, proved the hydrophobic nature of the composite membrane. A numerical simulation using Ansys 2020 software has been introduced to study the performance of the fabricated composite membrane when used in direct contact membrane distillation (DCMD). The numerical model has been validated with experimental work from the literature and showed an excellent match. The blank PS and composite PS/GNP membranes have been investigated and compared at different operating conditions, i.e., hot water supply temperature and system flow rate. The results show that the composite PS/GNP membrane outperforms the blank PS membrane at all studied operating conditions.

Development of Environment-Friendly Membrane for Oily Industrial Wastewater Filtration.

Latex phase blending and crosslinking method was used in this research work to produce nitrile butadiene rubber-graphene oxide (NBR-GO) membranes. This fabrication technique is new and yields environmentally friendly membranes for oil-water separation. GO loading was varied from 0.5 to 2.0 part per hundred-part rubber (pphr) to study its effect on the performance of NBR-GO membrane. GO was found to alter the surface morphology of the NBR matrix by introducing creases and fold on its surface, which then increases the permeation flux and rejection rate efficiency of the membrane. X-Ray diffraction analysis proves that GO was well dispersed in the membrane due to the non-existence of GO fingerprint diffraction peak at 2θ value of 10-12° in the membrane samples. The membrane filled with 2.0 pphr GO has the capability to permeate 7688.54 Lm-2 h-1 water at operating pressure of 0.3 bar with the corresponding rejection rate of oil recorded at 94.89%. As the GO loading increases from 0.5 to 2.0 pphr, fouling on the membrane surface also increases from Rt value of 45.03% to 87.96%. However, 100% recovery on membrane performance could be achieved by chemical backwashing.

Experimental Investigation of a Pilot Solar-Assisted Permeate Gap Membrane Distillation.

This research deals with the process of water desalination, involving an experimental design used to study a new prototype of a solar membrane distillation plant based on the weather conditions of Kairouan City, Tunisia. In this experiment, the pilot is left autonomous with the sun as the only source of energy. The operating process of a desalination plant consists of solar energy provided by the sun using solar energy collectors, which provide energy through their photovoltaic panels for heating brackish water. Additionally, the membrane used in this study was of the spiral wound design, which allowed for a compact arrangement besides effective internal heat recovery. The system start-up was successfully carried out and experimental studies were launched on various days of August 2020. During the experiment, the average production was approximately 15.92 L/m2 ap per day while the distillate's electoral conductivity amounted to 1865 µS/cm. Calculations revealed that the specific thermal energy consumption for the system ranged between 90 and 310 kWh/m3.

Electrospun Nanofibrous Scaffolds: Review of Current Progress in the Properties and Manufacturing Process, and Possible Applications for COVID-19.

Over the last twenty years, researchers have focused on the potential applications of electrospinning, especially its scalability and versatility. Specifically, electrospun nanofiber scaffolds are considered an emergent technology and a promising approach that can be applied to biosensing, drug delivery, soft and hard tissue repair and regeneration, and wound healing. Several parameters control the functional scaffolds, such as fiber geometrical characteristics and alignment, architecture, etc. As it is based on nanotechnology, the concept of this approach has shown a strong evolution in terms of the forms of the materials used (aerogels, microspheres, etc.), the incorporated microorganisms used to treat diseases (cells, proteins, nuclei acids, etc.), and the manufacturing process in relation to the control of adhesion, proliferation, and differentiation of the mimetic nanofibers. However, several difficulties are still considered as huge challenges for scientists to overcome in relation to scaffolds design and properties (hydrophilicity, biodegradability, and biocompatibility) but also in relation to transferring biological nanofibers products into practical industrial use by way of a highly efficient bio-solution. In this article, the authors review current progress in the materials and processes used by the electrospinning technique to develop novel fibrous scaffolds with suitable design and that more closely mimic structure. A specific interest will be given to the use of this approach as an emergent technology for the treatment of bacteria and viruses such as COVID-19.