ORCID Profile
0000-0001-8528-7490
Current Organisation
Southern Cross University
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Publisher: Elsevier BV
Date: 05-2020
Publisher: Elsevier BV
Date: 11-2019
Publisher: American Society of Agricultural and Biological Engineers
Date: 2017
Publisher: Elsevier BV
Date: 03-2017
Publisher: Elsevier BV
Date: 02-2020
Publisher: MDPI AG
Date: 13-01-2023
DOI: 10.3390/AGRICULTURE13010206
Abstract: There is a rising interest amongst Australian farmers to use disc seeders due to their ability to operate in high residue conditions and at higher speeds, commonly in the range of 12 to 15 km h−1. This paper reports on developing an analytical and discrete element method (DEM) force prediction model suited to a rotating flat disc blade operating at different sweep and tilt angles. To validate the models, field experiments were carried out with a flat disc blade at two tilt angles of 0 and 20° and four sweep angles of 6, 26, 45 and 90° in sandy soil. An analytical approach was developed following an experimental investigation that showed that only the forward portion of the disc blade is actively involved in generating soil failure, while the magnitude of this active portion of the soil-disc interface varied with sweep angle. The predicted active proportions correlated well with the experimental observations. As applying different sweep angles affects the direction of soil movement relative to the disc face, the directions of the friction and resultant forces at different sweep and tilt angles were determined. The equation of soil acceleration force was adapted to account for different sweep angles. Results showed that the predicted force fits relatively well with the measured data at 90, 45 and 26° sweep angle, while the low correlation between predicted and measured force at 6° sweep angle was due to the scrubbing reaction force not accounted for in the model. Results also showed that a better coefficient of determination (R2 = 0.93) was obtained between DEM vs. test results compared to the analytical model predictions (R2 = 0.86), particularly for predicting side forces. It was found from the study that both the developed analytical approach and DEM model enabled the prediction of soil forces at different sweep and tilt angles acting on a flat disc blade, which can assist in optimising disc design to lower the specific resistance.
Publisher: American Society of Agricultural and Biological Engineers
Date: 2018
Publisher: MDPI AG
Date: 20-07-2023
Abstract: A comprehensive model for micro-powered piezoelectric generator (PG), analysis of operation, and control of voltage doubler joule thief (VDJT) circuit to find the piezoelectric devices (PD’s) optimum functioning points are discussed in the present article. The proposed model demonstrates the power dependence of the PG on mechanical excitation, frequency, and acceleration, as well as outlines the load behaviour for optimal operation. The proposed VDJT circuit integrates the combination of voltage doubler (VD) and joule thief circuit, whereas the VD circuit works in Stage 1 for AC (alternating current)–DC (direct current) conversion, while a joule thief circuit works in Stage 2 for DC–DC conversion. The proposed circuit functions as an efficient power converter, which converts power from AC–DC and boosts the voltage from low to high without employing any additional electronic components and generating duty cycles. The electrical nature of the input (i.e., PD) of a VDJT circuit is in perfect arrangement with the investigated optimisation needs when using the proposed control circuit. The effectiveness of the proposed VDJT circuit is examined in terms of both simulation and experiment, and the results are presented. The proposed circuit’s performance was validated with available results of power electronics interfaces in the literature. The proposed circuit’s flexibility and controllability can be used for various applications, including mobile battery charging and power harvesting.
Publisher: Elsevier BV
Date: 09-2020
Publisher: Elsevier BV
Date: 2021
Publisher: MDPI AG
Date: 13-01-2023
DOI: 10.3390/AGRICULTURE13010202
Abstract: Disc seeders are commonly used in no-till farming systems, and their performance evaluation generally rely on expensive and time-consuming field experiments. Mathematical models can help speed up force-related evaluations and improve the understanding of soil-disc interactions, to assist the performance optimisation processes. Previous analytical force prediction models of disc blades have not accounted for the free rotation aspect of the disc blade. This paper develops an analytical force prediction model from the wide blade failure theory adapted to suit rotating flat disc blades operating at different sweep and tilt angles and compares predictions with Discrete Element Method (DEM) simulations. To validate the two models, experiments were performed on a remoulded sandy soil condition using a rotating flat disc set at two tilt angles of 0° and 20°, and four sweep angles of 6, 26, 45 and 90° the 3-dimensional force components of draught, vertical and side forces were measured. Results showed a higher coefficient of determination (R2 = 0.95) was obtained with analytical model predictions compared to DEM predictions (R2 = 0.85) for their agreement with the test results. It was found that both the developed analytical approach and the DEM model can be used to predict tillage forces at different sweep and tilt angles acting on a rotating flat disc blade.
Publisher: Elsevier BV
Date: 12-2014
Publisher: Elsevier BV
Date: 08-2018
Publisher: MDPI AG
Date: 06-02-2023
DOI: 10.3390/EN16041631
Abstract: This paper describes the detailed modelling of a vibration-based miniature piezoelectric device (PD) and the analysis modes of operation and control of a voltage doubler boost converter (VDBC) circuit to find the PD’s optimal operating conditions. The proposed VDBC circuit integrates a conventional voltage doubler (VD) circuit with a step-up DC-DC converter circuit in modes 1–4, while a non-linear synchronisation procedure of a conventional boost converter circuit is employed in modes 5–6. This integration acted as the voltage boost circuit without utilising duty cycles and complex auxiliary switching components. In addition, the circuit does not require external trigger signals to turn on the bidirectional switches. This facilitates the operation of VDBC circuit at very low AC voltage (Vac ≥ 0.5 V). Besides this, the electrical characteristics of VDBC circuit’s input (i.e., PD) perfectly concurs with the studied testing scenarios using impedance power sources (mechanical shaker). Firstly, the proposed circuit which can rectify the PD’s output was tested at both constant input voltage with varying excitation frequency and constant excitation frequency with varying input voltage. Next, a small-scale solar battery was charged to validate the feasibility of the performance of the proposed VDBC circuit. The proposed circuit achieved a maximum output voltage of 11.7 Vdc with an output power of 1.37 mW. In addition, the rectified voltage waveform is stable due to the sminimisation of the ripples. In addition, the performance of VDBC circuit was verified by comparing the achieved results with previously published circuits in the literature. The results show that the proposed VDBC circuit outperformed existing units as described in the literature regarding output voltage and power. The developed rectifier circuit is suitable for various real-life applications such as energy harvesting and battery charging.
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/SR19153
Abstract: The primary features of an effective and efficient furrow opener include controlled soil disturbance and low draught and vertical force requirements. When integrated in a no-tillage seeding system, furrow openers should also have the ability to assist, and not hinder, the functions of seeding system components – such as maintaining adequate surface residue distribution, accurate and uniform placement of seeds and fertiliser, and regular inter-plant spacing. This review highlights how these goals are affected by opener type, geometry and settings, and soil and residue conditions. Typically, tine openers cause greater soil disturbance than disc openers whereas disc openers are likely to cause residue hairpinning. Winged tine openers reduce residue interference with seed placement and support greater lateral seed spread. Inverted-T openers can achieve subsurface soil shattering, which helps conserve moisture and provides good seed–soil contact. A tine opener with concave cutting edge reduces soil disturbance relative to straight and convex cutting edges. Increasing rake angle, tine width and operating depth increase degree of soil disturbance and draught requirement. Increasing forward speed reduces residue interference with sowing but might decrease the accuracy and uniformity of depth and separation of seed and fertiliser placement. Relative to common openers, bentleg openers have lower draught and penetration force requirements while combining minimal lateral soil throw with high furrow backfill, even at speeds of up to 16 km h–1. The performance of bentleg openers need to be evaluated under residue conditions and in cohesive and adhesive soils. Recommendations for future research are presented.
Publisher: KSU Journal of Agriculture and Nature
Date: 28-02-2019
DOI: 10.18016/KSUTARIMDOGA.VI.430479
Abstract: İşçilik maliyetlerinin yüksek ve toprağın organik madde miktarının düşük olduğu ülkelerde, toprak üzerine serpilen gübre ve diğer organik maddelerin toprağın alt katmanlarına hızlı ve ekonomik bir şekilde karıştırılması amacı ile, işletme maliyetleri diğer tarım aletlerine göre daha düşük olan, kültivatörler kullanılabilir. Kültivatörün organik maddeyi toprağa hangi oranda karıştırdığı ve bu karışım miktarının değişik hız ve toprak işleme derinliklerinde nasıl değiştiğinin deneysel olarak araştırılması zaman alıcı ve maliyetli bir işlemdir. Bu nedenle bu çalışmada kültivatörün toprak üzerine serpilen organik maddeleri toprağa ne derece karıştırdığı, ayrık elemanlar metodu kullanılarak, bilgisayar ortamında, simüle edilmiştir. Ayrıca kültivatörün üzerine ek levhalar eklenerek karıştırma miktarındaki değişim incelenmiştir. Bunlara ek olarak kültivatör üzerine etki eden çeki ve dikey kuvvetler incelenmiştir. Çalışmanın sonuçları ek levha kullanılarak toprağın alt katmanlarına karıştırılacak organik madde miktarının artırılabileceğini, fakat bu durumda çeki kuvvetinin artacağını göstermiştir. Çalışmanın sonuçları ayrık elemanlar metodunun tarım makineleri tasarımında etkili bir hızlı modelleme aracı olarak kullanılabileceğini göstermiştir.
Publisher: American Society of Agricultural and Biological Engineers
Date: 17-07-2016
Publisher: Elsevier BV
Date: 09-2015
Publisher: Elsevier BV
Date: 05-2014
Publisher: MDPI AG
Date: 20-11-2022
DOI: 10.3390/AGRICULTURE12111961
Abstract: Selecting the appropriate tyre configuration and settings for heavy farm vehicles is important to ensure that soil compaction and power loss in rolling resistance are minimised and traction is optimised. This study investigated the effect of front-wheel assist (FWA, ≈75 kN) and four-wheel drive (4 WD, ≈100 kN) tractors fitted with different tyre configurations (single, dual), tyre sizes and inflation pressures on soil strength (a proxy for soil compaction), and rolling resistance. Single-pass tests were performed on a Typic Argiudoll (≈23% clay, bulk density: 1305 kg m−3) managed under permanent no-tillage. Results showed that average power losses in rolling resistance were 7.5 kN and 5 kN for the 4 WD and FWA tractors, respectively. The average rut depth increased by approximately 1.4 times after a pass of the 4 WD compared with the FWA tractor. The soil cone index (0–600 mm depth) increased from 2023 kPa (before traffic) to 2188 and 2435 kPa after single passes of the FWA and 4WD tractors, respectively (p 0.05). At the centreline of the tyre rut, dual tyres reduced the soil cone index a little compared with single tyres, but they significantly increased the volume of soil over which soil strength, and therefore soil compaction, was increased. For both tractors (regardless of tyre configuration or settings), soil strength increased to the full measured depth (600 mm), but relative changes before vs. after traffic became progressively smaller with increased soil depth. The power loss in rolling resistance was consistently greater with the heavier tractor, and rut depth was directly related to tyre inflation pressure.
Publisher: KSU Journal of Agriculture and Nature
Date: 30-04-2018
Publisher: Elsevier BV
Date: 08-2017
Publisher: Elsevier BV
Date: 08-2021
Publisher: MDPI AG
Date: 30-03-2023
DOI: 10.3390/AGRICULTURE13040790
Abstract: Due to the rapid increase in world population, the demand for food has increased dramatically [...]
Publisher: Elsevier BV
Date: 07-2018
Publisher: Elsevier BV
Date: 2020
Publisher: American Society of Agricultural and Biological Engineers
Date: 17-07-2016
Publisher: MDPI AG
Date: 27-01-2023
DOI: 10.3390/AGRICULTURE13020305
Abstract: Due to their (a) lower draught force requirements and (b) ability to work at deeper operation depths and faster operation speeds, disc ploughs have gained interest in Australia. A modified version of the disc plough that involves removing every second disc and fitting larger and often more concave discs has become popular. However, the development of the one-way modified disc plough is in its infancy, and a detailed analysis is required, particularly on soil movement. Historically, the soil movement analysis of the soil–tool interactions is conducted using empirical methods. However, the experimental tests are resource and labour intensive. When the soil and tool interaction can be accurately modelled, more efficient tools can be designed without performing expensive field tests, which may only be undertaken at certain times of the year. This study modelled the interaction between soil and a one-way modified disc plough using the discrete element method (DEM). As the disc plough is a passive-driven tool, the rotational speed of the disc plough was modelled using DEM-MBD (multi-body dynamic) coupling. The results of the study show that DEM-MBD coupling can predict the rotational speed of the disc plough with a maximum relative error of 6.9%, and a good correlation was obtained between the DEM-predicted and actual soil movement (R2 = 0.68).
Publisher: Elsevier BV
Date: 07-2021
Publisher: Elsevier BV
Date: 09-2021
Publisher: Elsevier BV
Date: 09-2021
Publisher: Elsevier BV
Date: 05-2018
Publisher: Elsevier BV
Date: 2015
Publisher: MDPI AG
Date: 06-2023
DOI: 10.3390/S23115257
Abstract: Piezoelectric energy harvesting systems have been drawing the attention of the research community over recent years due to their potential for recharging/replacing batteries embedded in low-power-consuming smart electronic devices and wireless sensor networks. However, conventional linear piezoelectric energy harvesters (PEH) are often not a viable solution in such advanced practices, as they suffer from a narrow operating bandwidth, having a single resonance peak present in the frequency spectrum and very low voltage generation, which limits their ability to function as a standalone energy harvester. Generally, the most common PEH is the conventional cantilever beam harvester (CBH) attached with a piezoelectric patch and a proof mass. This study investigated a novel multimode harvester design named the arc-shaped branch beam harvester (ASBBH), which combined the concepts of the curved beam and branch beam to improve the energy-harvesting capability of PEH in ultra-low-frequency applications, in particular, human motion. The key objectives of the study were to broaden the operating bandwidth and enhance the harvester’s effectiveness in terms of voltage and power generation. The ASBBH was first studied using the finite element method (FEM) to understand the operating bandwidth of the harvester. Then, the ASBBH was experimentally assessed using a mechanical shaker and real-life human motion as excitation sources. It was found that ASBBH achieved six natural frequencies within the ultra-low frequency range ( Hz), in comparison with only one natural frequency achieved by CBH within the same frequency range. The proposed design significantly broadened the operating bandwidth, favouring ultra-low-frequency-based human motion applications. In addition, the proposed harvester achieved an average output power of 427 μW at its first resonance frequency under 0.5 g acceleration. The overall results of the study demonstrated that the ASBBH design can achieve a broader operating bandwidth and significantly higher effectiveness, in comparison with CBH.
Publisher: MDPI AG
Date: 23-02-2023
DOI: 10.3390/AGRICULTURE13030541
Abstract: In agricultural machinery design and optimization, the discrete element method (DEM) has played a major role due to its ability to speed up the design and manufacturing process by reducing multiple prototyping, testing, and evaluation under experimental conditions. In the field of soil dynamics, DEM has been mainly applied in the design and optimization of soil-engaging tools, especially tillage tools and furrow openers. This numerical method is able to capture the dynamic and bulk behaviour of soils and soil–tool interactions. This review focused on the various aspects of the application of DEM in the simulation of tillage and furrow opening for tool design optimization. Different contact models, particle sizes and shapes, and calibration techniques for determining input parameters for tillage and furrow opening research have been reviewed. Discrete element method predictions of furrow profiles, disturbed soil surface profiles, soil failure, loosening, disturbance parameters, reaction forces, and the various types of soils modelled with DEM have also been highlighted. This pool of information consolidates existing working approaches used in prior studies and helps to identify knowledge gaps which, if addressed, will advance the current soil dynamics modelling capability.
Publisher: American Society of Agricultural and Biological Engineers
Date: 2018
Publisher: Elsevier BV
Date: 2019
Publisher: MDPI AG
Date: 04-2024
DOI: 10.3390/S23031372
Abstract: In recent years, harvesting energy from ubiquitous ultralow-frequency vibration sources, such as biomechanical motions using piezoelectric materials to power wearable devices and wireless sensors (e.g., personalized assistive tools for monitoring human locomotion and physiological signals), has drawn considerable interest from the renewable energy research community. Conventional linear piezoelectric energy harvesters (PEHs) generally consist of a cantilever beam with a piezoelectric patch and a proof mass, and they are often inefficient in such practical applications due to their narrow operating bandwidth and low voltage generation. Multimodal harvesters with multiple resonances appear to be a viable solution, but most of the previously proposed designs are unsuitable for ultralow-frequency vibration. This study investigated a novel multimode design, which included a bent branched beam harvester (BBBH) to enhance PEHs’ bandwidth output voltage and output power for ultralow-frequency applications. The study was conducted using finite element method (FEM) analysis to optimize the geometrical design of the BBBH on the basis of the targeted frequency spectrum of human motion. The selected design was then experimentally studied using a mechanical shaker and human motion as excitation sources. The performance was also compared to the previously proposed V-shaped bent beam harvester (VBH) and conventional cantilever beam harvester (CBH) designs. The results prove that the proposed BBBH could harness considerably higher output voltages and power with lower idle time. Its operating bandwidth was also remarkably widened as it achieved three close resonances in the ultralow-frequency range. It was concluded that the proposed BBBH outperformed the conventional counterparts when used to harvest energy from ultralow-frequency sources, such as human motion.
Location: Australia
Start Date: 2014
End Date: 2019
Funder: Department of Primary Industries and Regional Development, Government of Western Australia
View Funded ActivityStart Date: 2019
End Date: 2021
Funder: Grains Research and Development Corporation
View Funded Activity