Recent trends in development of hematite (α-Fe2O3) as an efficient photoanode for enhancement of photoelectrochemical hydrogen production by solar water splitting

Solar-assisted water splitting using photoelectrochemical (PEC) cell is an environmentally benign technology for the generation of hydrogen fuel. However, several limitations of the materials used in fabrication of PEC cell have considerably hindered its efficiency. Extensive efforts have been made to enhance the efficiency and reduce the hydrogen generation cost using PEC cells. Photoelectrodes that are stable, efficient and made of cost-effective materials with simple synthesizing methods are essential for commercially viable solar water splitting through PEC technology. To this end, hematite (α-Fe₂O₃) has been explored as an excellent photoanode material to be used in the application of PEC water oxidation owing to its suitable bandgap of 2.1 eV that can utilize almost 40% of the visible light. In this study, we have summarized the recent progress of α-Fe₂O₃ nanostructured thin films for improving the water oxidation. Strategic modifications of α-Fe₂O₃ photoanodes comprising nanostructuring, heterojunctions, surface treatment, elemental doping, and nanocomposites are highlighted and discussed. Some prospects related to the challenges and research in this innovative research area are also provided as a guiding layout in building design principles for the improvement of α-Fe₂O₃ photoanodes in photoelectrochemical water oxidation to solve the increasing environmental issues and energy crises.     

Rheology,curing and time-dependent behavior of epoxy/carbon nanoparticles systems

This study delved into the characterization of epoxy nanocomposites containing diglycidyl ether of bisphenol-A (DGBEA), graphene nanoplates (GN), and carbon nanotubes (CNT) across a range of weight percentages (0.05% to 2%). The nanocomposites were produced through a process involving mechanical stirring and ultrasonication. To assess compatibility, three-dimensional solubility parameters (3DSP) were employed. CNT demonstrated superior compatibility with epoxy and triethylenetetramine (TETA), due to its higher amount of oxygenated species in nanoparticle surface compared to GN. A rheological percolation phenomenon occurred in CNT systems at concentrations above 0.2%, while GN did not display percolation even at 2% concentration. Incorporating nanoparticles led to increased curing enthalpy due to surface functional groups. As the percolation network formed, viscosity rose, and a reduced glass transition temperature (T_g) indicated restricted molecular mobility. Surprisingly, T_g consistently increased by approximately 27°C during composite annealing, regardless of nanoparticle type or concentration. This was attributed to forming a three-dimensional network structure potentially originating from reactions between nanoparticle-oxygenated groups and the epoxy matrix. This phenomenon was crucial in heightened creep and irreversible deformations, setting these nanocomposites apart from pure resin behavior.     

Thermal and mechanical properties of thermoplastic urethanes made from crystalline and amorphous azelate polyols

Polyester polyols from renewable resources have gained significant interest in the field of polyurethane chemistry. Two sets of segmented TPUs were prepared from crystalline and amorphous azelate polyols, 4,4′-methylenebis(phenyl isocyanate), and 1,4-butanediol as a chain extender at a mole ratio of 1:2:1, respectively. Bio-1,3-propanediol (1,3-PDO) and 1,5-pentanediol (PTDO) were used to prepare crystalline azelate polyols, while 1,2-propanediol (1,2-PDO) and 2,2′-dimethyl-1,3-propanediol (NPG) were used to prepare amorphous azelate polyols. All TPUs displayed clear glass transition temperatures (T _gs) in between −36 and − 24 °C, associated with azelate polyols soft segments, which are decreasing with increasing diols chain lengths in azelate polyols. TPUs based on crystalline azelate polyols exhibited higher mechanical properties and better heat resistance in comparison to their counter parts. Besides, TPU based on 1,3-PDO azelate showed lower percentage of hysteresis indicating lower heat build-up. This is essentially good for TPUs that are to be used in dynamic applications such as rollers and wheels. Hence, the study on structure–property correlation of the crystalline and amorphous azelate polyols and their effect on TPUs properties suggest that crystalline azelate polyols are suitable for dynamic application of TPU, and amorphous azelate polyols are suitable for coatings and adhesives applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47890.     

Smart Lightning Detection System for Smart-City Infrastructure Using Artificial Neural Network

Wireless Personal Communications - Smart city infrastructure for lightning detection is one of the most important parameters for building protection. To get outcomes within a short frame of time...     

Incense (bakhour) smoke exposure is associated with respiratory symptoms and impaired lung function among adults: A cross-sectional study in Eastern Province of Saudi Arabia

Burning incense (bakhour) is a common cultural practice in Saudi Arabia. However, its health risk assessment has rarely been studied. This study aims to investigate the association between exposure to incense smoke on lung function impairments and respiratory symptoms among young adults in Saudi Arabia. A community-based cross-sectional study was designed with a representative study sample (N = 125) in the Eastern Province of Saudi Arabia. Study participants, exposed group (n = 45), working in bakhour shop and matched control (n = 80), no history of occupational exposure to bakhour smoke, were recruited randomly from the population registry. Socio-demographic and respiratory symptom information were collected through a questionnaire developed based on European Community Respiratory Health Survey II (ECRHS II). Lung function measurements were conducted using a field spirometer. The overall prevalence of wheezing or whistling was 16.8%, with a higher prevalence in exposed group 35.5%. In adjusted models, exposed to incense smoke remained positively associated with respiratory symptoms: wheezing or whistling; breathlessness; chest tightness shortness of breath; woken up by an attack of coughing. Our study suggests that inhaled incense smoke in occupation or at home is a risk factor of lung function impairments among adult population in Saudi Arabia.     

Evaluating the accessibility of higher education institution websites in the State of Kuwait: empirical evidence

Universal Access in the Information Society - The objective of this study is to evaluate the current state of accessibility of higher education institution websites in the State of Kuwait....     

Automated disease diagnosis and precaution recommender system using supervised machine learning

Similar to many other professions, the medical field has undergone immense automation during the past decade. The complexity and rise of healthcare data led to a surge in artificial intelligence applications. Despite increased automation, such applications lack the desired accuracy and efficiency for healthcare problems. To address the aforementioned issue, this study presents an automatic health care system that can effectively substitute a doctor at an initial stage of diagnosis and help save time by recommending the necessary precautions. The proposed approach comprises two modules where Modul-1 aims at training the machine learning models using the disease symptoms dataset and their corresponding symptoms and precautions. Preprocessing and feature extraction are done as prerequisite steps. In Module-1 several algorithms are applied to the disease dataset such as support vector machine, random forest, extra trees classifier, logistic regression, multinomial naive Bayes, and decision tree. Module-2 interacts with the user (patient) through which the patient can describe the illness symptoms using a microphone. The voice data are transformed into text using the Google speech recognizer. The transformed data is later used with the trained model for disease prediction, as well as, recommending the precautions. The proposed approach achieves an accuracy of 99.9% during the real-time evaluation.

     

Up-scaling microbial fuel cell systems for the treatment of real textile dye wastewater and bioelectricity recovery

ABSTRACT

In this work the energy recovery in microbial fuel cell was studied by electrically stacking its three individual units into series and parallel arrangements. The power output was higher in parallel stacking by 2.07 and 14.77 times than series and individual units respectively. The rate of degradation of dye wastewater was in order of individual Microbial Fuel Cell (MFC) < series stack < parallel stack. The corn cob biochar was used as an additive in the MFC to improve the efficiency of the individual MFC unit. The addition of 0.5 g corn cob biochar enhanced the power output to 38.6 mW/m² from 0.47 mW/m² in the MFC individual unit without the biochar additive. The simultaneous COD reduction, TDS reduction and decolourisation of dye wastewater achieved are 82.14%, 68% and 74.8% respectively. The current work demonstrates that the dose of biochar and parallel stacking are a framework to achieve enhanced dye removal and bioenergy recovery via microbial fuel cell.     

Production of N-methyldiethanolamine di-ester via heterogeneous transesterification of palm methyl ester over modified calcium oxide catalyst by metal oxides

The production cycle of the heterogeneous catalyzed-transesterification of methyl ester and alkanolamine for the production of esterquats precursor can be considered as a cleaner and sustainable process. This process is an important alternative route as opposed to the conventional homogeneous catalysis as it can eliminates the formation of wastewater, consumes less toxic chemical and reduce the production cost through catalyst reuse. Calcium oxide (CaO)-based catalysts which include pure CaO and modified CaO by other metal oxides were employed in this study for the production of alkanolamine ester, a precursor of esterquats. The basicity and textural properties of these catalysts were characterized using TPD-CO₂ and N₂ physisorption, respectively. Transesterification activity of CaO-based catalysts successfully showed a high di-ester yield of more than 85% at 160°C, 80 mbar, 4 wt% of catalyst dosage, 6 h reaction time, methyl palmitate to N-methyldiethanolamine mole ratio of 2:1 and agitation speed of 150 rpm. ZnO/CaO catalyst rendered the best durability characteristic as it exhibited constant activities for three subsequent runs with 85% di-ester yield. ZnO/CaO showed high catalytic activity similar to pure CaO catalyst with low leaching of Ca active phase and better reusability than that of pure CaO catalyst, that shows loss of its activity after the first cycle.