Assessment of Domestic Wastewaters as Potential Growth Media for Chlorella vulgaris and Haematococcus pluvialis

Domestic wastewater contains chemical compounds that can be used as nutrients for microalgae. Removing these chemical compounds from wastewater by microalgae might help in reducing the operation cost of wastewater management while minimizing the cultivation cost for large-scale microalgae metabolite production. In this study, domestic wastewater collected from Indah Water Konsortium (IWK), Kuala Lumpur, Malaysia, was assessed as growth media for two types of microalgae, namely Chlorella vulgaris and Haematococcus pluvialis. The biomass growth and nutrient removal efficiency of total nitrogen (TN), total phosphorus (TP), and total ammonia (TAN) in different concentrations of diluted wastewater were measured. The results showed that biomass concentration (0.227 g/L), biomass productivity (0.029 g/L/day), and specific growth rate (0,284 d-1) yielded by C. vulgaris in 14 days of 80% wastewater were comparable to those microalgae grew in standard Bold’s Basal medium (BBM). Besides, C. vulgaris grew in 50% wastewater to remove TN, TP, and TAN with the highest removal efficiency (>88%). For H. pluvialis, the biomass concentration in all wastewater concentrations was lower than BBM. The removal efficiencies of TN and TP were lower than 55%, but more than 80% for removal efficiency of TAN in 50% and 80% wastewater. Hence, C. vulgaris has better growth performance and nutrient removal efficiency than H. pluvialis. These findings indicated that IWK domestic wastewater could be used as growth media for microalgae, especially C. vulgaris.

Octave Band Technique for Noise Measurement at the Source, Path, and Receiver of Gas Turbines in Oil and Gas Facilities

Noise measurement is essential for industrial usage. However, further attention to preventing noise pollution is needed, especially when working with equipment generating a high noise level, such as gas turbines. This study aims to determine the best way to perform noise measurement and analyze the octave band frequency generated by noise pollution caused by gas turbine equipment. Data from site measurements show that the gas turbines produce more than 85 dB of noise with a Z-weighted measurement. A noise measuring investigation was conducted to obtain the data for the 1/3 octave band. A frequency-domain was used to comprehend the properties of the noise measurement frequency band. The frequency band was classified into three different zones called low, medium, and high frequency, which is useful in noise measurement analysis to identify a viable solution to reduce the noise. On-site sampling was performed at the source, path, and receiver of three separate gas turbine locations within oil and gas operations. The 1/3 octave band data collection results at the sound source, path, and receiver demonstrate the noise level distribution at the perimeter of gas turbine installations in the low and medium frequency ranges. Most of the high noise frequency range is between 250 Hz and 2 kHz for source, path, and receiver. All acquired values are compared to the Department of Safety and Health (Occupational Safety and Health (Noise Exposure) Regulations 2019 in Malaysia. As a result, oil and gas service operators can monitor and take countermeasures to limit noise exposure at oil and gas facilities.

Accuracy of Ultrasound and Magnetic Resonance Cholangiopancreatography Findings in the Diagnosis of Biliary System Stones

This study aimed to evaluate the diagnostic accuracy of magnetic resonance cholangiopancreatography (MRCP) and Ultrasound (US) images for the diagnosis of biliary system stones, as well as to assess the consistency between MRCP and US findings. The study sample included 200 cases (90 males and 110 females) with symptomatic biliary system stones between 14 and 82 years. All cases underwent both the US and MRCP imaging for biliary system diagnosis. The study revealed that the most prominent age group with symptoms of biliary system stones was the 33-60-year-old group. It also found that the accuracy of US and MRCP in detecting gallbladder (GB) stones compared with the final diagnosis was 94% and 91%, respectively, with moderate conformity between their results. The accuracy of US and MRCP images in detecting common bile duct (CBD) stones was 61% and 98%, respectively, with fair conformity between their results. In addition, there is a significant agreement between the MRCP and US results in detecting the GB and CBD stones with an agreed percentage of 74% and 71%, respectively. The study concluded that US is the preferred imaging technique for patients with symptomatic gallbladder stones, whereas MRCP is a trustworthy investigation for common bile duct stones.

The Effect of Elevated Temperature on Engineered Cementitious Composite Microstructural Behavior: An Overview

This paper discusses the quantitative bibliographic data derived from scientific publications on Engineered Cementitious Composites (ECC) subjected to elevated temperature, the influence of elevated temperature on the mechanical properties, particularly the compressive strength and microstructure behavior of Engineered Cementitious Composites (ECC) mixtures based on the review of previous pieces of literature. Systematic literature reviews were employed as the methodology in this study. The age of related publications selected to be reviewed was limited to publications for the past ten years, 2010 to December 2020. It was found from available research that exposure of the ECC specimen at the elevated temperature starting from 200oC significantly reduced the compressive strength when the temperature increases, melting of fiber and increase of porosity causes the dramatically increase micro-cracks.

Optical Properties of Cu2O Thin Films Impregnated with Carbon Nanotube (CNT)

This study investigates CNT-doped Cu2O thin film deposited by spray pyrolysis technique at a substrate temperature of 100°C. The samples were annealed at temperatures of 200°C and 230°C for 30 minutes. The effect of CNT doping on certain optical properties, such as extinction and absorption coefficients, a refractive index of doped Cu2O thin films were examined. The absorbance of the doped samples increases within the visible range and decreases in the ultraviolet range of the electromagnetic spectrum (EM). Both absorbance and extinction coefficients increased with temperature making the samples a good candidate for use as absorbance layer in device fabrication. In addition, there was an increase in direct bandgap with the increase in CNT concentration of the thin films. The result of the study revealed that CNT doping has a significant effect on the properties of Cu2O.

Effect of Water Absorption on Flexural Properties of Kenaf/Glass Fibres Reinforced Unsaturated Polyester Hybrid Composites Rod

This study investigates the effect of water absorption on the flexural strength of kenaf/ glass/unsaturated polyester (UPE) hybrid composite solid round rods used for insulating material applications. Three volume fractions of kenaf/glass fibre 20:80 (KGPE20), 30:70 (KGPE30), and 40:60 (KGPE40) with three different fibre arrangement profiles of kenaf fibres were fabricated by using the pultrusion technique and were aimed at studying the effect of kenaf fibres arrangement profile and its content in hybrid composites. The fibre/ resin volume fraction was maintained constant at 60:40. The dispersion morphologies of tested specimens were observed using the scanning electron microscope (SEM). The findings were compared with pure glass fibre-reinforced UPE (control) composite. The water absorption results showed a clear indication of how it influenced the flexural strength of the hybrid and non-hybrid composites. The least affected sample was observed in the 30KGPE composite type, wherein the kenaf fibre was concentrated at the centre of a cross-section of the composite rod. The water absorption reduced the flexural strength by 7%, 40%, 24%, and 38% of glass/UPE (control), 20KGPE, 30KGPE, and 40KGPE composites, respectively. In randomly distributed composite types, the water absorption is directly proportional to the volume fraction of kenaf fibre. At the same time, flexural properties were inversely proportional to the volume fraction of kenaf fibres. Although the influence of water absorption on flexural strength is low, the flexural strength of pultruded hybrid composites was more influenced by the arrangement of kenaf fibre in each composite type than its fibre loading.

A Review of Thermal Design for Buildings in Hot Climates

Most of the developed world currently lives above the tropic of Cancer in cold climate regions. It follows that most of the top architectural firms are from the same countries, and most of their work is based on that experience. Experience that does not travel well to hotter countries. This paper is mainly concerned with the climates of the Middle East region, which are hot in summer and have mild or cold winters, and where the humidity ranges from dry to humid. It is a review of the factors, designs, and solutions that designers sometimes ignore, undervalue, or on the other hand, put too much weight on when working in such climates. An overview of thermal solutions is conducted, and a critique and suitability of each one for hotter climates are offered. Some of the solutions, which are thought to be helpful, have little benefit, especially traditional ones, which are not up to present-day standards and lifestyles. Others, such as courtyards, do more harm than good. A couple of case studies to evaluate houses with and without thermal measures showed improvements of 23-48%. The paper will evaluate architectural, cooling, and building design solutions according to suitability in dry and medium humidity, warm and hot countries.

Development of Attendance and Temperature Monitoring System using IoT with Wireless Power Transfer Application

Enclosed areas pose a greater risk of transmitting infectious and bacterial diseases. The proposed system helps prevent disease by tracking students’ daily body temperature before entering the school premises. Each student will be provided with a unique QR code containing the student information, such as their name and class. The QR code needs to be scanned first by the camera-equipped smartphone before reading the body temperature. The thermometer will record the student’s body temperature and send the information to the smartphone via Bluetooth. The student’s profile will be updated with the recorded daily temperature. An Android application will be developed to scan the QR code and display the students’ profiles and information. In order to design a battery-less system, the system will be integrated with a wireless power transfer circuit. Based on the simulation results, the wireless power transfer circuit can be used as a wireless charger for the smartphone used in the system or for charging the thermometer’ of the thermometer.

Synthesis and Performance of PAFS Coagulant Derived from Aluminium Dross

Polymerised aluminium ferric sulphate (PAFS) was prepared from aluminium dross as a coagulant in wastewater treatment. The effects of leaching time, leaching temperature, and sulfuric acid concentrations on the turbidity removal of the wastewater were investigated, and the optimum conditions were determined using response surface methodology. The results showed that the optimum PAFS preparation conditions were at a leaching time of 60 minutes, a leaching temperature of 65°C, and a sulfuric acid concentration of 1 mol/L. Furthermore, experiments were performed to investigate the effect of coagulant dosages using the PAFS prepared under the optimum leaching conditions, settling time and initial pH of the wastewater on the turbidity removal efficiency. As a result, it was found that the optimum coagulation conditions for PAFS coagulants were at a settling time of 15 minutes, coagulant dosage of 0.5g, and raw water pH 8. Under these optimum conditions, the turbidity removal efficiency of the wastewater was 91.45%. The purpose of this study was to investigate the possibility of aluminium dross utilisation as a coagulant agent for wastewater treatment. Therefore, it can be concluded that PAFS prepared by leaching metal oxides from aluminium dross is an effective wastewater coagulant.

Arabic Handwriting Classification using Deep Transfer Learning Techniques

Arabic handwriting is slightly different from the handwriting of other languages; hence it is possible to distinguish the handwriting written by the native or non-native writer based on their handwriting. However, classifying Arabic handwriting is challenging using traditional text recognition algorithms. Thus, this study evaluated and validated the utilisation of deep transfer learning models to overcome such issues. Hence, seven types of deep learning transfer models, namely the AlexNet, GoogleNet, ResNet18, ResNet50, ResNet101, VGG16, and VGG19, were used to determine the most suitable model for classifying the handwritten images written by the native or non-native. Two datasets comprised of Arabic handwriting images were used to evaluate and validate the newly developed deep learning models used to classify each model’s output as either native or foreign (non-native) writers. The training and validation sets were conducted using both original and augmented datasets. Results showed that the highest accuracy is using the GoogleNet deep learning model for both normal and augmented datasets, with the highest accuracy attained as 93.2% using normal data and 95.5% using augmented data in classifying the native handwriting.