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One of the most influential factors affecting the rate of corrosion of a buried pipeline and the design of the cathodic protection systems is the conductivity of the soil. The present paper is designed to study the effect of this factor on the design of cathodic protection systems, i.e. the current required to achieve comprehensive protection. Several corrosive environments were studied within the laboratory. The classification of environment corrosivity approved by ASTM was the base of the categorization of these environments. These environments were simulated by adding certain amount of distilled water mixed with weighed amount of sodium chloride to the soil. Several runs were carried out, whereas the conductivity of the soil and the linear polarization curves for the cathode and the anode were obtained during each run. The boundary element method (BEM) was used to compute the total current required using linear polarization curves as the boundary conditions for calculations. The BEASY software based on BEM was used to compute the total current required. The relationship between the total current and the soil conductivity values were drawn. Two equations governing and controlling this relationship were derived. Keywords: Soil conductivity, Boundary element, Cathodic protection, Computational methods, Linear polarization curves

Abstract The hydrothermal carbonization (HTC) technique is known for its advantages in producing hydrochar from biomass samples with high water content compared to conventional pyrolysis techniques. This study utilized HTC to produce an activated carbon catalyst from renewable mesocarp fiber derived from palm oil processing. The introduction of K2CO3 and Cu(NO3)2 produced a bifunctional catalyst suitable for conversion of used cooking oil to biodiesel. The catalyst possessed a mesoporous structure with a BET surface area of 3909.33 m2/g. An optimum treatment ratio of 4:1 (K2CO3: Cu(NO3)2) provided elevated basic (5.52 mmol/g) and acidic (1.68 mmol/g) concentrations on the catalytic surface, which promoted esterification and transesterification reactions. Maximum yield (96.4%) of biodiesel was obtained at 70 °C for 2 h with 5 wt% catalyst and a 12:1 molar ratio of methanol to oil. The catalyst endured up to 5 reaction cycles while maintaining biodiesel yields of more than 80%. These findings indicated that HTC pretreatment yielded a high-quality bifunctional catalyst for conversion of low-quality used cooking oil for production of biodiesel.

Road traffic crashes represent a substantial global public health issue. In Saudi Arabia, which is the focus area of this research, road traffic crashes kill over 130,000 people annually, accounting for almost 5% of deaths in that country. A cross-sectional study with 316 participants holding a valid Saudi driver’s license was conducted via the internet from December 2019 to March 2020 to collect information about the prevalence of risky driving habits among Saudi drivers. The sample was predominantly men and aged between 20 and 39, which is representative of the population of drivers in Saudi Arabia. Drivers generally reported engaging in safe behaviors, although they did state that they drove above the legal speed limit, drove aggressively around slow drivers, and became distracted while driving with some frequency. Multivariate analyses suggested men took more risks than women and younger drivers took more risks than older ones. We conclude that the behavior among drivers in Saudi Arabia generally matches those in other cultures and countries, with men and young adults taking the most risks while driving. Preventative strategies should be developed and implemented in Saudi Arabia.

A fixed Filter-Thyristor Controlled Reactor (FF-TCR) type of compensator is proposed to improve the power factor of a single phase thyristor-controlled inductive load and it is shown that this compensator gives better power factor improvement than the more generally used FC-TCR type of compensator. Analysis is carried out for the exact equivalent circuit of an FF-TCR compensator containing two filter branches tuned to the third and the fifth harmonics respectively. It is shown that with an FF-TCR compensator the power factor improvement is much better when the source impedance is large. However, even with a small source impedance, a reasonable improvement in power factor is realised. It is further shown that even when the source impedance is large the distortion in the terminal voltage waveform is kept within reasonable limits. The analytical results are verified experimentally.

Due to the rapid advancement in the use of photovoltaic (PV) energy systems, it has become critical to look for ways to improve the energy generated by them. The extracted power from the PV modules is proportional to the output voltage. The relationship between output power and array voltage has only one peak under uniform irradiance, whereas it has multiple peaks under partial shade conditions (PSCs). There is only one global peak (GP) and many local peaks (LPs), where the typical maximum power point trackers (MPPTs) may become locked in one of the LPs, significantly reducing the PV system’s generated power and efficiency. The metaheuristic optimization algorithms (MOAs) solved this problem, albeit at the expense of the convergence time, which is one of these algorithms’ key shortcomings. Most MOAs attempt to lower the convergence time at the cost of the failure rate and the accuracy of the findings because these two factors are interdependent. To address these issues, this work introduces the dandelion optimization algorithm (DOA), a novel optimization algorithm. The DOA’s convergence time and failure rate are compared to other modern MOAs in critical scenarios of partial shade PV systems to demonstrate the DOA’s superiority. The results obtained from this study showed substantial performance improvement compared to other MOAs, where the convergence time was reduced to 0.4 s with zero failure rate compared to 0.9 s, 1.25 s, and 0.43 s for other MOAs under study. The optimal number of search agents in the swarm, the best initialization of search agents, and the optimal design of the dc–dc converter are introduced for optimal MPPT performance.

This work focuses on preparing TiO2, CdS, and composite TiO2:CdS thin films for photovoltaic applications by thermal evaporation. The suggested materials exhibit very good optical and electrical properties and can play a significant role in enhancing the efficiency of the device. Various microscopy and spectroscopy techniques were considered to investigate the optical, morphological, photoluminescence, and electrical properties. FTIR confirms the material identification by displaying some peaks in the fingerprint region. UV Vis spectroscopy yields high transmission (80–90%) and low absorbance (5–10%) within the spectral region from 500 nm to 800 nm for the composite thin films. The optical band gap values for CdS, TiO2, and TiO2:CdS thin films are 2.42 eV, 3.72 eV, and 3.6 eV. XRD was utilized to analyze the amorphous nature of the thin films, while optical and SEM microscopy were employed to examine the morphological changes caused by the addition of CdS to TiO2. The decrease in the bandgap of the composite thin films was determined by the Tauc plot, which is endorsed due to the band tailing effects. Photoluminescence spectroscopy depicts several emission peaks in the visible region when they are excited at different wavelengths, and the electrical measurement enhances the material conductivity. Furthermore, the proposed electron transport materials (TiO2, CdS, TiO2:CdS) were simulated with different perovskite materials to validate their design by employing the SCAPS-1D program and assess their performance in commercial implementation. The observed results suggest that TiO2:CdS is a promising candidate to be used as an ETM in PSC with enhanced productivity.

Truck traffic is one of the major inputs to any pavement design procedure. In almost all pavement design procedures, truck traffic is represented in terms of the accumulated Equivalent Axle Load (EAL) applications. The level of EAL applications is mainly dependent on the prevailing values of truck factors. Thus efforts have to be made to accurately estimate truck factor values based on local loading conditions. The current practice of the Ministry of Communications (MOC) involves recording axle weights of loaded trucks only without including empty trucks. This, in turn, leads to higher truck factor estimates and consequently over-designed pavement structures. The main objective of this study is to quantify the effect of excluding empty trucks when estimating truck factors, on highway pavement design. The truck factors associated with loaded trucks were determined from MOC data files. The empty truck factors were determined from a field sample consisting of 4000 empty trucks. The empty-adjusted truck factors were calculated as the weighted average of the two truck factor values. An analysis has been conducted to study the effects of using the empty-adjusted truck factors on pavement design instead of loaded truck factors, using the AASHTO design procedure. The analysis indicated that the average truck factor for empty trucks is about 1.15, the average truck factor for loaded trucks is about 9.87 and the average empty-adjusted truck factor is about 6.63. It also showed that excluding empty trucks would result in over-designs with an average of about SR 1.0 / m2 or about SR 3500 / km-lane extra construction cost.