Rebar corrosion due to chlorides in synergy with sodium, potassium, and magnesium

The ability of steel reinforced concrete to withstand long service life is ensured by the strong binding between the concrete and the rebar. Although rebar corrosion deterioration in the presence of chlorides is well known, it is important to note that these anions are never present in isolation, i.e., other cations are also present within the exposed environment. Consequently, a study was conducted to investigate the rebar deterioration due to chlorides in the presence of different cations. A well-controlled laboratory experiment for assessing the corrosivity of sodium chloride, potassium chloride and magnesium chloride was conducted. The galvanostatic pulse technique was used to investigate the concrete-steel interfacial structure, which was modelled after a modified Randles circuit. Analysis revealed influences of the associated cations during the rebar corrosion process. A normalisation approach was used to compare chloride attacks on the rebar due to different salt solutions. Results suggest that chloride attacks in the presence of sodium cations are relatively corrosive

Novel ICT Applications for Pacific Agri-Food and Nutritious Systems: Best Practices, Gaps and Opportunities in Fiji

A study was conducted by a team led by Dr Bibhya Sharma of The University of the South Pacific on ICT tools used by the agricultural sector in Fiji. The seminal aim of the assignment, commissioned under the CTA-led project on Promoting Nutritious Food Systems in the Pacific Islands, is not only to create awareness in the Pacific but also to help farmers and consumers leverage on current and new ICT tools, such as mobile apps, 3D printers and blockchain technology for best results. At the initial stage, a Fiji wide survey was carried out in various institutions including research institutions, academic organisations, private institutions, mobile service providers, development agencies and the government ministries. Agriculture still remains one of the major contributors of Fiji’s Gross Domestic Product (GDP) and heralds a stronghold of its economy. Moreover, agriculture in Fiji continues to grow rapidly with a lot of investments from the Fijian Government and help from outside donors. However, there have been issues such as late harvests, irregular weather pattern, failing yields, reduction in agricultural land areas, poor and late deliveries, and by-product wastage seen as reasons causing a decline in the agricultural sector. These reasons are not new to Fiji, rather they have been in existence for a long period of time now. The decline of the sector which is still contributing so much to the country’s GDP makes a serious case for changes and innovations

Model of fractional - order resonant wireless power transfer system for optimal output

Wireless Power Transfer (WPT) technology has recently gained popularity in applications and research topics. It enables the transfer of electrical energy from a source to a load without connecting wires physically. The WPT system is commonly studied classically using integer order capacitors and inductors. Nonetheless, such integer order based systems have drawbacks, such as low output power, poor transmission efficiency and sensitivity to parameter variations. This paper proposes a fractional order resonant WPT circuit whereby both the transmitting and receiving ends are composed of a fractional capacitor and inductor to overcome such problems. In this paper, the overall performance is studied based on its output power and efficiency considering a series-parallel topology. The effect of fractional order in fractal elements will be analyzed to observe the optimal combination of components to achieve the maximum output power with higher efficiency. Through a comparative analysis of the results, several combinations of circuit parameters can provide a theoretical understanding for implementing an experimental system

Adoption of grid - tie solar system at residential scale

Traditionally, remote and urban communities worldwide have been supplied electricity almost completely by fossil fuel generators to accommodate for electricity needs. Currently, the integration of renewable energy sources (RESs) into the current power generation systems can offer attractive economic and environmental merits, including considerable fuel savings and carbon dioxide emission reductions. In relation to sustainability, efficiency and economic feasibility, solar photovoltaic (PV) is one of the most promising sources of RESs which is being touted as a leading solution to long-term electrification and development problems in rural and urban parts of Pacific Island Countries (PICs). In this work, a grid-tie PV system is instigated at a residential scale. The idea of this research is not to claim the power output from the PV system but to show the feasibility of a grid-tie system at a residential scale. This will help the PICs, non-profit organisations and the government better share scarce resources towards achieving their energy goals and be in line with Sustainable Development Goal (SDG) 7, ensuring access to affordable, reliable, sustainable and modern energy for all

Characterizing Australia's east coast cyclones (1950–2019)

East coast cyclones (ECCs) provide an essential reprieve from dry periods across eastern Australia. They also deliver flood‐producing rains with significant economic, social and environmental impacts. Assessing and comparing the influence of different types of cyclones is hindered by an incomplete understanding of ECC typology, given their widely variable spatial and temporal characteristics. This study employs a track‐clustering method (probabilistic curve‐aligned regression model) to identify key cyclonic pathways for ECCs from 1950 to 2019. Six spatially independent clusters were successfully distinguished and further sub‐classified (coastal, continental and tropical) based on their genesis location. The seasonality and long‐term variability, intensity (maximum Laplacian value ± two days) and event‐based rainfall were then evaluated for each cluster to quantify the impact of these storms on Australia. The highest quantity of land‐based rainfall per event is associated with the tropical cluster (Cluster 6), whereas widespread rainfall was also found to occur in the two continental lows (Cluster 4 and 5). Cyclone tracks orientated close to the coast (clusters 1, 2 and 3) were determined to be the least impactful in terms of rainfall and intensity, despite being the most common cyclone type. In terms of interannual variability, sea surface temperature anomalies suggest an increased cyclone frequency for clusters 1 (austral winter) and 4 (austral spring) during a central Pacific El Niño. Further, cyclone incidence during IOD‐negative conditions was more pronounced in winter for clusters 1, 2, 3 – and clusters 4 and 5 in spring. All cyclones also predominantly occurred in SAM‐positive conditions. However, winter ECCs for clusters 1 and 3 had a higher frequency in SAM‐negative. This new typology of ECCs via spatial clustering provides crucial insights into the systems that produce extreme rainfall across eastern Australia and should be used to inform future hazard management of cyclone events. This article is protected by copyright. All rights reserved

Improving Overall Equipment Effectiveness by Enabling Autonomous Maintenance Pillar for Integrated Work Systems

Integrated Work System (IWS) and Overall Equipment Effectiveness (OEE) are two popular approaches used by production firms to identify and eliminate production losses. In a highly competitive business environment, companies must increase their efficiency in the manufacturing process to support resilient business continuity. While OEE is widely used as a quantitative tool for measuring the performance of total productive maintenance (TPM), the IWS approach integrates equipment, processes, and involvement of people into a unified approach to reduce costs, improve quality, and increase productivity. Principally, there is an alignment between the two concepts. The IWS has the potential to maximize OEE to eliminate equipment failure and defects, minimize downtime, and maximize productivity with less time, effort, and waste. The purpose of this work is to compare the performance of the OEE with the implementation of the IWS pillar, i.e., autonomous maintenance (AM). The rollout of the AM pillar was carried out on the two identical packaging machines (HLP1) with a speed of 120 packets per minute. The data which is shown in this paper is for both machines during the operational hours. Finally, the analysis showed positive results for both machines within a five-month period, with an increase of 27% and 15% in OEE, respectively. Later in the discussion, the root cause and SWOT analysis were perused for OEE and TPM, respectively, in this paper

Reactive control and obstacle avoidance of a LEGO NXT Robot

Robotics has always been a fascinating field. The ability to control guided motion has seen major developments in the industrial world. This project was a continuing project. The codes provided with the resources for this project was developed by the supervisor, Dr. Praneel Chand as part of his Phd research. Previously a pair of EE 300 students has worked on the Lego robot with limited success. The main purpose for the design of this Lego robot was to detect and avoid obstacles. Initially the Lego robot was not able to run through the GUI (graphical user interface) simulation. Simulation tests were carried out along with hardware experiments to troubleshoot. also the battery of the NXT brick drained faster. It was found out that the sensors were giving wrong readings. Sensor readings were corrected through the use of correct formulas in the program codes. Two more sensors were added to give more accurate information to the robot of its surroundings. An external power source was put on the platform to power up the sensors externally which took off some load from the NXT battery. The NXT Lego robot was not fully able to achieve obstacle detection and avoidance because a big time difference between distance data call to the NXT brick, there were errors in the real time detection and avoidance of the Lego robot

Optimized Tongue Driven System Using Artificial Intelligence

This paper presents a cost effective design of a wearable wireless tongue drive system (TDS) for disabled individuals, particularly with spinal cord injuries (SCIs). We propose a basic TDS whose language is specifically designed for issuing movement based commands, be it a gadget or a self-governing transport chair. While the overall industrial penetration of TDS is low, we offer a cheap and straightforward design for a TDS that consists of items which amount to as low as US$30. A data-driven based approach has been used to classify the tongue-gestures with a response time of less than 0.25 seconds. Compared with other machine learning algorithms, the proposed TDS is equipped with shallow neural networks that govern all the decisions when it comes to classifying the tongue gesture. This has been achieved after a thorough data analysis and rigorous comparison with other classification techniques along with hardware deployment. With its open architecture, the newly designed TDS can be an ideal tool to control other movement based peripherals. The final test accuracy amounts to 93.4% when the TDS is tested on human subjects

Rebar corrosion due to chlorides in the presence of different cations

Recent attention on effects of climate change in the Pacific island countries (PIC’s) have focused on a multitude of areas which are at risk in the Pacific region. These include food security, flora and fauna, land accessibility, groundwater contamination and so on. These aspects are essential for sustainable development of the small island states in the Pacific region. One issue, which appears synonymous with climate change in the Pacific is sea-level rise. The rising sea level can have detrimental effects on civil infrastructure since its intrusion further inland can lead to deterioration of nearby civil metallic infrastructure due to corrosion. Since metropolisation of major PIC’s are mainly near the sea or along coast line, this presents a significant problem within the overall paradigm of sustainable development. In this regards, a study was undertaken to investigate the influences of different chloride salts (i.e. NaCl, KCl, MgCl2) on the corrosion of steel re-inforcing bars (rebar’s) in concrete mortars. This study is important to understand structural health conditions, especially for foundations in ground, and to understand the corrosion intensities in the presence of different cations, which can be significantly controlled by groundwater migration. The galvanostatic pulse technique was used to evaluate the effect of varying chloride contents of different salts on rebar corrosion. Results from this study are presented in an attempt to provide a conceptual model for understanding the interaction of aforementioned salts with metallic infrastructure. A holistic discussion is presented which are important for sustainable development in the PIC’s

Lyapunov based driverless vehicle in obstacle free environment

This paper presents a new technology for designing, simulation, implementation and validation of a driverless vehicle system with the use of the Arduino microcontroller, ultrasonic sensors and stepper motors are integrated to Lyapunov based control scheme. The goal is specifically to develop a driverless vehicle system which is able to move from an initial to target location in an obstacle free environment in 2D workspace while taking the shortest route to the destination. Mathematical modeling for the vehicle has also been done in order to find the dynamics of the vehicle which would be used in the software simulation of the vehicle and subsequently verified through experimental design. The new methodology for the prototype and validation are presented with interesting scenarios. The final design and the methodology to reach the final design, prototyping, testing and verification and validation of the output will be presented