The prepared silver/chitosan nanocomposite and chitosan nanoparticles in this study may demonstrate the potential in optimizing the minimum amount required to achieve complete inactivation of various Coliform bacteria in Nile water. Chitosan nanoparticles were prepared based on the ionic gelation of the prepared chitosan and silver nanoparticles were reduced by Solenostemma Argel extract. Finally, chitosan silver-loaded nanoparticles were prepared by dispersing silver nanoparticles onto the chitosan nanoparticles. The SEM images exhibited a diameter range of 10 nm–30 nm for both of the fabricated silver nanoparticles and chitosan nanoparticles. The UV-Vis analysis confirmed the formation of Ag nanoparticles by the appearance of the characteristic peak at 410 nm. The antibacterial activity of chitosan nanoparticles and silver-loaded nanoparticles was evaluated against the Coliform bacteria. Results show an improvement in the inhibition of the growth of various bacteria tested when silver nanoparticles were introduced which was (0.03g/100ml). Consequently, chitosan silver-loaded nanoparticles could be recommended as an efficient antibacterial material for water disinfection.

This work reports on the use of diatomaceous earth (DE) waste and organic binder derived from Corchorus olitorius, locally known as “Mrenda” in the design of an efficient water filtration membranes. Charcoal powder was incorporated to enhance the porosity of the membrane. The firing was done at temperatures varying from 700.0 °C to 1150.0 °C. The DE waste samples comprised 79.0% silica (by mass) and 11.0% total flux content compared to porter’s clay that had 50.0% silica, 28.8% AL2O3 and 7.0% total flux content. On the other hand, the “Mrenda” binder contained 6.5% total organic matter. The use of the plant-derived binder enhanced the mechanical strength of the greenware by 52.7% and the fired membranes by 152.2%. The fabricated DE waste-based membranes were 15.0% stronger than clay-based ceramic membranes prepared under similar conditions. A sintering temperature of 900.0 °C was optimal in producing porous membranes for filtering of 4.1 liters of water per hour. The pore diameter of the membranes fabricated from DE waste only ranged between 2.0 nm – 99.0 nm. On micro-organisms filtering efficacy, the DE waste-based membranes and those fabricated with 5.0% charcoal were 99.9% and 88.4% effective in the removal of E. coli and Rotavirus respectively.

Plastics generally play a very important role in a plethora of industries, fields and our everyday lives. In spite of their cheapness, availability and important contributions to lives, they however, pose a serious threat to the environment due to their mostly non-biodegradable nature. Recycling into useful products can reduce the amount of plastic waste. Thermal degradation (Pyrolysis) of plastics is becoming an increasingly important recycling method for the conversion of plastic materials into valuable chemicals and oil products. In this work, waste Polyethylene terephthalate (PET) water bottles were thermally converted into useful gaseous and liquid products. A simple pyrolysis reactor system has been used for the conversions with the liquid product yield of 65 % at a temperature range of 400°C to 550°C. The chemical analysis of the pyrolytic oil showed the presence of functional groups such as alkanes, alkenes, alcohols, ethers, carboxylic acids, esters, and phenyl ring substitution bands. The main constituents were 1-Tetradecene, 1-Pentadecene, Cetene, Hexadecane, 1-Heptadecene, Heptadecane, Octadecane, Nonadecane, Eicosane, Tetratetracontane, 1-Undecene, 1-Decene). The results are promising and can be maximized by additional techniques such as hydrogenation and hydrodeoxygenation to obtain value-added products.

In this study, biological hydroxyapatite (HAp) was synthesized from catfish (Pangasius hypophthalmus) bones. First, the as-received catfish bones were de-proteinized in open air, and then converted to HAp by a solid state heat treatment method at a temperature of 900 °C for a holding time of 2 h in a muffle furnace. X-ray diffraction (XRD) analysis confirmed that HAp with high crystallinity of 99.9% was formed matching the structural properties of flouro-apatite with crystallite sizes of approximately 37.1 nm. The morphology of the HAp prepared showed irregularly shaped particles and revealed the appearance of open pores with a less agglomerated structure and a Ca/P ratio of about 1.58. The specific mechanical properties: hardness, compressive strength and fracture toughness of the catfish derived scaffolds were recorded as 480 MPa, 1.92 MPa, and 5.72 Mpa.m1/2, respectively. The fracture toughness of the HAp derived scaffolds suggests that the produced biomaterial is promising for biomedical applications. These findings are useful for the production and application of the HAp powders prepared from catfish bones, and further suggests a possible low-cost route for producing inexpensive ceramics using natural catfish bones.

Pneumonia has contributed greatly to child mortality, especially among children under the ages of five in sub-Saharan Africa, killing more children than the number of children dying from HIV/AIDS. The current methods of diagnosing pneumonia involved physical examination and chest x-ray which are limited by low accuracy, high error margins, higher cost, and stands the risks of inducing cancer. In this work, a low-cost, non-invasive biomedical device was designed and developed to improve accuracy in diagnosing pneumonia. The device functions to detect fluid in a lung consolidated by pneumonia. Dry grouting sponge was used as a phantom for a healthy lung, while a wet sponge was used to mimic a pneumonia-consolidated lung. Surface exciter was used to produce sound waves which travelled through one side of the phantom and are detected on the other end using an electronic stethoscope. The signals detected were digitally analyzed using MATLAB and AUDACITY software. The differences in resonant frequencies from the power spectrum analysis of sound waves as they travelled through the sponges were used to distinguish between a pneumonia-consolidated lung and a healthy lung.

Nanocomposite hydrogels of poly-n-isopropyl were prepared by incorporating gold and magnetite nanoparticles. The nanocomposite-based hydrogels formed were geometrical, ∼7.3 mm in diameter and 5 mm thick (in the swollen state). Morphological analysis was characterized by a scanning electron microscope. Drug-loaded hydrogels were subjected to laser heating at 1 W, 1.5 W and 2 W for 20 min in each laser cycle. The metabolic activities of the cells were analysed. The photothermal conversion efficiency of the nanocomposite hydrogels was also evaluated for P(NIPA)-AuNP-PG and P(NIPA)-MNP-PG to be 36.93 and 32.57 %, respectively. The result was then discussed for potential applications whereby metal-based hydrogels can be employed in microfluidic devices for targeted cancer drug delivery.

Various cases of medical implants produced through additive manufacturing (AM) in Ti6Al4V have been reported in literature. Not all manufacturing processes used, were qualified. In striving to deliver certified AM medical implants and devices, an ISO 13485:2016 quality management system was implemented in the Centre for Rapid Prototyping and Manufacturing (CRPM) of the Central University of Technology, Free State (CUT) in Bloemfontein, South Africa. This certification is valid for design, development and production of patient-specific custom-made titanium implants, preoperative models, jigs and cutting-guides in nylon through AM, and contract-production of these products. For maintaining this quality management system, the generation of data to validate the individual processes in the AM process-chain is crucial to prove the DMLS product-quality of CRPM’s products. During the past five years, directed research data was produced and published to prove that medical implants produced through DMLS can fully comply with the accepted international standards for material, physical, chemical and mechanical properties of such parts. The paper discusses the quality management system’s establishment; materials research projects executed to generate validation data are mentioned; and examples of customised titanium implants for restoring the quality of life of patients are shown.

Bentonite is the most widely used foundry binder. Most of the iron castings are made in greensand systems which make use of bentonite as a binder. The bentonite used in greensand moulding is usually activated with sodium carbonate to achieve desirable properties. Activation of bentonite is known to improve mould related properties like giving a high wet tensile strength and improving the durability. The practice of activation is more common with calcium bentonite. A number of bentonite deposits tend to remain unbeneficiated due to their low cation exchange capacity (CEC) which are regarded as low quality commercial grade. The primary characteristic that shows the increased activation is the swelling index of the bentonite. This study investigated the influence of rehydration and activation in improving the quality of low commercial grade sodium bentonite. The bentonite samples were activated with sodium carbonate. Rehydration and activation was seen to improve the CEC and swelling index. The increase in CEC and swelling index was however not consistent with the gains in sodium.