Dye-sensitised Photocatalyst for Photocatalytic Whole Water Splitting to Produce Hydrogen in a Twin Photoreactor

Organic dye-sensitised SrTiO3:Rh and WO3 were served as H2 catalysts and O2 catalysts in a Z-scheme system to conduct photocatalytic pure water splitting. To enhance the light absorption capacity, the composites of organic dye (N3, N719, Z907, black dye, C101, and K19) and SrTiO3:Rh were synthesised via physical adsorption and then verified by the performance of photocatalytic hydrogen evolution. Among these dyes, N3-SrTiO3:Rh revealed visible light absorption and exhibited the best photocatalytic activity. Therefore, N3 dye was adopted, and silane coupling agents were used to form chemical bonding with SrTiO3:Rh. Furthermore, the photocatalytic pure water splitting of N3-SrTiO3:Rh was investigated in a single reactor, and a twin photoreactor with Fe2+ and Fe3+ ions served as the electron mediators, respectively. The highest quantum efficiency can reach 0.0259% in a twin reactor when compared with the single reactor (0.0052%) because of the improvement in the light absorption from N3 and inhibition of the backward reaction of water splitting. Consequently, organic dye-sensitised photocatalysts are highly effective and eco-friendly in conducting photocatalytic pure water splitting.

Green Synthesis of Iron Oxide Nanoparticle Using Coffee Seed Extract and Its Antibacterial Activity

The discovery of reliable and green processes for metal oxide nanoparticles synthesis is particularly crucial and exhibits huge potential in various applications. Thus, in this paper, a fast, single step and environmental-friendly method to synthesize iron oxide nanoparticles (Fe2O3-NPs) by bio-reduction of iron salts Fe2+ and Fe3+ under the presence of coffee seeds (CS) aqueous extract was demonstrated. The characteristics of the synthesised Fe2O3-NPs were investigated by using X-ray diffraction (XRD) and ultraviolet-visible (UV-Vis) spectrophotometry techniques. The XRD result revealed that the Fe2O3-NPs produced display highly crystalline property with a cubic structure and the average size of the resulted particle is ranging from 23.2 nm to 37.5 nm. Additionally, the energy band gap (Eg) calculated also showed that maghemite (γ-Fe2O3) nanoparticles was successfully synthesised by using CS extract. The resulted nanoparticles are highly feasible in the inhibition of the growth of pathogenic microorganism.

Critical Factors Causing Material Wastes in Building Construction Projects

Construction sites generate a large amount of material wastes and have become a common problem with associated risks in Ethiopia. However, the sources of such wastes are not well recognised. Therefore, the purpose of this research was to analyse the risk factors that contribute to material wastes in building construction projects. To achieve this goal, the factors that cause construction wastes were identified from literature and construction experts via focus group discussions and personal interviews. Following this, the factors were subjected to a questionnaire survey to identify the most critical factors of construction wastes. The questionnaire was distributed purposively to 85 construction experts representing contractors, consultants, and clients and 70 questionnaires were duly received for analysis. The data were analysed with a mean score and ranked to identify the most critical factors generating material wastes at construction sites. According to the results of the study frequent changes made to the design, poor strategies for waste minimisation, improper storage of material, poor site management, poor planning and supervision, and errors of contract document were the most critical factors causing construction wastes.

Isothermal Air Flow Investigation in Industrial Baking Oven of Different Impeller Locations using Computational Fluid Dynamics (CFD) Approach

Computational fluid dynamics (CFD) modelling was performed on a forced convection oven to investigate the isothermal airflow. Three oven design configurations based on their impeller location (back, side, and top wall) were compared with respect to their Turbulence Kinetic Energy (TKE) profile to determine the optimal configuration design for quick uniform baking. The air velocity was estimated from both experimental and modelling approaches at specific points in an oven with the back walled impeller. The CFD model was validated resulting in a calculation error of 30.34% of actual velocity which was mainly due to limitation in grid density and the turbulence modelling. The other two oven configurations were simulated and their average TKE data were extracted and compared. The third configuration (impeller at the top wall) was found to have the highest average TKE of 3.55 m2/s2 followed by the first configuration (impeller at the back wall) with 3.30 m2/s2 which provides a relatively uniform TKE distribution across the cavity. The findings show the significance of impeller placement in oven performance.

Measures to Provide Settlements with Quality Drinking Water: Assessment of the Potential by the Example of the Odessa Agglomeration

The rapid urbanisation of the settlements of the Odessa agglomeration has negatively affected the quality of the drinking water that is transported to consumers. The purpose of this study was to determine the most effective measures to provide settlements with quality drinking water. In order to achieve this goal, possible options for measures were considered, and an assessment and comparative analysis of the potential of the proposed options were executed. The most effective measures were evaluated on two criteria: compliance with the principles of sustainable development and whether the measures were effective, reliable and comfortable for consumers when implemented. The factors that influenced the decision-making were the situation and conditions of the implementation of the measures, laboratory tests of the source water and laboratory tests of the water after the treatment process and consumer awareness of participation. The findings demonstrated that a measure was effective if it met the stated criteria. The results of the study are planned to be used as reference material in the elaboration of an integrated plan for the development of settlements, for decision-making in the organisation of recreation and health-related areas and for other resource planning activities.

Analytical Solution for the Boundary Value Problem of Elastic Beams Subjected to Distributed Load

Analytical solution for the boundary value problem (BVP) of elastic beams subjected to distributed load was investigated. Based on the study, dynamic application curves are developed for beam deflection. The partial differential equation of order four were analysed to determine the dynamic response of the elastic beam under consideration and solved analytically. Effects of different parameters such as the mass of the load, the length of the moving load, the distance covered by the moving load, the speed of the moving and the axial force were considered. Result revealed that the values of the deflection with acceleration being considered are higher than the system where acceleration of the moving load is negligible. These obtained results are in agreement with the existing results.

Impact Modified Polyvinyl Chloride Based Thermoplastic Elastomers: Effect of Nitrile Butadiene Rubber and Graphene Oxide Loading

A new thermoplastic elastomer with improved impact and tensile properties was produced through melt blending of graphene oxide filled nitrile butadiene rubber (NBR-GO) and polyvinyl chloride (PVC) without the addition of plasticisers and thermal stabilisers. Nitrile butadiene rubber (NBR) compounds, with and without graphene oxide (GO) are prepared through latex compounding method and cured, prior to blending with PVC. The effect of NBR and NBR-GO loading on the process-ability and physico-mechanical properties of PVC blends were evaluated. The addition of NBR and NBR-GO improved tensile strength (TS), impact strength and swelling resistance of PVC. Addition of NBR also increased the stiffness of PVC due to higher elasticity of NBR as compared to PVC. Optimum impact strength, TS and swelling resistance was achieved with the addition of 10 wt. % NBR-GO. Good miscibility between NBR and PVC, and additional reinforcement by GO is responsible for enhancement of impact and TS. NBR-GO showed greater miscibility in PVC as compared to NBR as proven by morphological observation under scanning electron microscope. Morphological observation reveals that micro-cracks formation on PVC/30NBR surface which is responsible for low impact, tensile and swelling properties as compared to PVC/30NBR-GO composite.

Effects of Heating Temperature and Load Weight on Rheological Properties of Waste Plastic Cup

Analysis of heating temperature and load weight to the rheological properties of waste plastic cups is very important to gain fundamental understanding of the structure, characteristics, and processability of the material. The samples were tested using melt flow indexer. The heating temperature investigated were 180°C, 190°C, 200°C, 210°C, 220°C and 230°C, and the weight load were 1,875 g, 2,160 g, 2,835 g, 3,035 g and 3,450 g. The results obtained showed that the rheological properties of products such as melt flow index, shear stress and shear rate increased and the viscosity decreased with the increasing of heating temperature and load weight. For higher heating temperatures, the melt flow index, shear stress and shear rate of waste plastic cup increased significantly with the increasing load weight whereas the viscosity of waste plastic cup did not decrease significantly with the increasing load weight.

Analytical Solution for the Boundary Value Problem of Euler-Bernoulli Beam Subjected to Accelerated Distributed Load

The study of dynamic response of beam-like structures to moving or static loads has attracted and still attracting a lot of attention due to its wide range of applications in the construction and transportation industry especially when transverse by travelling masses. Hence, analytical solution for the boundary value problem (BVP) of elastic beams subjected to distributed load was investigated. The partial differential equation of order four were analysed to determine the dynamic response of the elastic beam under consideration and solved analytically. Effects of different parameters such as the mass of the load, the length of the moving load, the distance covered by the moving load, the speed of the moving and the axial force were considered. Result revealed that the values of the deflection with acceleration being considered increases than the system where acceleration of the moving load is negligible.

Magnetic Resonance Imaging Image Segmentation and Brain Tumour Detection Using Pulse-Coupled Neural Networks

Image processing can be defined as a functional structure to correct and change the images viewed and their interpretation. One of the applications of digital image processing is using image processing techniques in the component and image segmentation. One of these techniques is magnetic resonance imaging (MRI) in the medical world. In this article, a brain tumour detection system and various anomalies and abnormalities are presented where image pre-processing and preparation include image enhancement, filtering and noise reduction. Then image segmentation is done by a pulse neural network. Next, the image features are extracted and finally, the tumour and abnormal area are separated from the normal area by the algorithms. In this research, the feature selection and integration method are used and the most important statistical features of brain MRI images are used to improve brain tumour detection. Along with the studies done and the implementation of tumour detection systems, the following suggestions can be provided for future researches and the tumour detection system will work more efficiently. The pulse-coupled neural network (PCNN) can be used for image segmentation in the pre-processing stage, especially in the image filtering.