In recent years, most cities have faced great demand for electricity supply due to rapid population growth and industrialization. Supplying sufficient electrical energy, while reducing greenhouse gas emissions, is one of the major concerns of policymakers and scientists all over the world. In Saudi Arabia, local authorities are increasingly aware of the necessity of reducing the environmental impact of nonrenewable energy by exploring alternative sustainable energy sources and improving buildings’ energy efficiency. Recently, building-integrated photovoltaic (BIPV) technology has been regarded as a promising technology for generating instantaneous sustainable energy for buildings. To achieve a substantial contribution regarding zero energy buildings, solar energy should be widely used in residential buildings within the urban context. This paper examines how to achieve an appropriate model for integrating photovoltaics on the rooftop of residential buildings in Hail city to provide alternative energy sources. The estimated rooftop areas in Hail city, utilizable for PV application were calculated. Using PV*SOL simulation software, the performance ratio and the system efficiency, as well as the annual energy output in several tilt angles, were determined and presented. The amount of energy expected when using all effective roof area in the city was also calculated. The amount of CO₂ emissions that could be reduced as a result of using a PV system was estimated. The results show a significant area of rooftop suitable for PV system in residential buildings in Hail city, which exceeds 9 million square meters. On the other hand, the performance ratio and the system efficiency are affected by the tilt angle of the PV module, where the efficiency increases with higher tilt angle, this is due to the PV module temperature, where, with the decrease in the PV module temperature its efficiency increases. The results indicate that the 30° tilt PV produced the highest amount of energy, whereas the 75° tilt PV records the smallest one although it achieves the best possible efficiency. There is a significant amount of energy produced from the use of all residential rooftops in Hail, and there is also a significant reduction in the amount of CO₂ emissions. It is expected that this research would develop innovative building design strategies and specifications allowing for better climate and energy efficiency as well.

The problem of metal-induced toxicity is proliferating with an increase in industrialization and urbanization. The buildup of metals results in severe environmental deterioration and harmful impacts on plant growth. In this study, we investigated the potential of two ornamental plants, Catharanthus roseus (L.) G.Don and Celosia argentea L., to tolerate and accumulate Ni, Cr, Cd, Pb, and Cu. These ornamental plants were grown in Hoagland’s nutrient solution containing metal loads (50 µM and 100 µM) alone and in combination with a synthetic chelator, ethylenediaminetetraacetic acid (EDTA) (2.5 mM). Plant growth and metal tolerance varied in both plant species for Ni, Cr, Cd, Pb, and Cu. C. roseus growth was better in treatments without EDTA, particularly in Ni, Cr, and Pb treatments, and Pb content increased in all parts of the plant. In contrast, Cd content decreased with EDTA addition. In C. argentea, the addition of EDTA resulted in improved plant biomass at both doses of Cu. In contrast, plant biomass reduced significantly in the case of Ni. In C. argentea, without EDTA, root length in Cd and Cu treatments was significantly lower than the control and other treatments. However, the addition of EDTA resulted in improved growth at both doses for Pb and Cu. Metal accumulation in C. argentea enhanced significantly with EDTA addition at both doses of Cu and Cd. Hence, it can be concluded that EDTA addition resulted in improved growth and better metal uptake than treatments without EDTA. Metal accumulation increased with EDTA addition compared to treatments without EDTA, particularly for Pb in C. roseus and Cu and Cd in C. argentea. Based on the present results, C. roseus showed a better ability to phytostabilize Cu, Cd, and Ni, while C. argentea worked better for Ni, Cd, Cu, and Pb.

Phenolic compounds are toxic and ominously present in industrial effluents, which can end up in water bodies, causing potential damage to living organisms. This study employed the dried biomass of freshwater green microalgae Chlorella vulgaris to remove phenol and 2-chlorophenol from an aqueous environment. C. vulgaris was grown under different phosphorus- (P) starved conditions, and biomass was treated with sulfuric acid. It was observed that reducing the P level enhanced the lipid content by 7.8 times while decreasing protein by 7.2 times. P-starved C. vulgaris dried biomass removed phenol and 2-chlorophenol by 69 and 57%, respectively, after 180 min from the contaminated water. Acid-treated P-starved C. vulgaris dried biomass removed phenol and 2-chlorophenol by 77 and 75%, respectively, after 180 min. Thus, an economical and eco-friendly P-starved and acid treated C. vulgaris biomass has better potential to remove phenol and 2-chlorophenol from contaminated ground water and industrial wastewater.

This paper presents the flexural analysis of functionally graded plates resting on elastic foundations using new two-dimensional (2D) and quasi-three-dimensional (quasi-3D) higher order shear deformation theories. The main interesting feature of this theory is that it proposes a new displacement field with undetermined integral variables which involves only five unknown functions, unlike other shear and normal deformation theories, hence making it easier to use. A parabolic transverse shear deformation shape function satisfying the zero shear stress conditions on the plate outer surfaces is considered. The elastic foundation follows the Pasternak mathematical model. The material properties change continuously across the thickness of the FG plate using different distributions: power law, exponential, and Mori–Tanaka models. The governing equations of FG plates subjected to sinusoidal and uniformly distributed loads are established through the principle of virtual works and then solved via Navier’s procedure. In this work, a detailed discussion on the influence of material composition, geometric parameters, stretching effect, and foundation parameters on the deflection, axial displacements, and stresses is given, and the obtained results are compared with those published in previous works to demonstrate the accuracy and the simplicity of the present formulations. The different obtained results were found to be in good agreement with the available solutions of other higher-order theories. The proposed model is able to represent the cross section warping in the deformed shape and to demonstrate the validity and efficiency of the approach, the findings reported herein prove that this theory is capable of predicting displacements and stresses more accurately than other theories, as its results are closer when compared to numerical methods reported in other literatures.

This study presents a hyperbolic shear deformation theory for free vibration of functionally graded plates on elastic foundations. The field of displacements is chosen based on the assumptions that axial and transverse displacements consist of components due to bending and shear. The components of the axial shear displacements give rise to the parabolic variation in the shear strain through the thickness, such that the shear stresses vanish on the plate boundaries. Therefore, the shear correction factor is not necessary. The material properties of the functionally graded plate are assumed to vary through the thickness according to the power law of the volume fraction of the constituents. The elastic foundation is modeled as a Pasternak foundation. The equations of motion are derived using Hamilton’s principle. The analytical solutions were established from Navier’s approach, and the results obtained are found to be in good agreement with the solutions of three-dimensional elasticity and with the solutions of the various plate theories. The effects of the power law index, the thickness ratio, and the foundation parameters on the natural frequency of the plates were also evaluated.

The natural quality of groundwater tends to be degraded by industry, agriculture, and wastewater. There are several alternatives to prevent migration and the spread of pollution in groundwater. Some alternatives are physical such as grouting, or slurry walls. Others could be hydrodynamic containment by injection or pumping wells. Injection wells are used to confine a pollutant in place or dilute its concentration by injecting clean water into the aquifer. Pumping wells are used to discharge the pollutants out of the groundwater reservoir or act as interceptors. In this research, the hydraulic characteristics and behavior of the hydrodynamic methods are investigated by using numerical simulation. In this investigation, the numerical model MT3D has been integrally used with the flow model MODFLOW. Injection/pumping rate, screen length and layer, and the number of wells are considered. The results have shown that increasing the rate or the number of injection/pumping wells permits less pollution spread. Changing the screen length of the injection/pumping wells is not effective in preventing pollution from spreading in the long term. Changing the number of wells has more effect on a containment spread. Injection wells can prevent the spread of contaminants more than pumping wells.