Browsing by Author "Luo, Zhenhua"
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Item Open Access Advancing hydrogen: a closer look at implementation factors, current status and future potential(MDPI, 2023-12-08) Kaheel, Sultan; Ibrahim, Khalifa Aliyu; Fallatah, Gasem; Lakshminarayanan, Venkatasubramanian; Luk, Patrick; Luo, ZhenhuaThis review article provides a comprehensive analysis of the hydrogen landscape, outlining the imperative for enhanced hydrogen production, implementation, and utilisation. It places the question of how to accelerate hydrogen adoption within the broader context of sustainable energy transitions and international commitments to reduce carbon emissions. It discusses influencing factors and policies for best practices in hydrogen energy application. Through an in-depth exploration of key factors affecting hydrogen implementation, this study provides insights into the complex interplay of both technical and logistical factors. It also discusses the challenges of planning, constructing infrastructure, and overcoming geographical constraints in the transition to hydrogen-based energy systems. The drive to achieve net-zero carbon emissions is contingent on accelerating clean hydrogen development, with blue and green hydrogen poised to complement traditional fuels. Public–private partnerships are emerging as catalysts for the commercialisation of hydrogen and fuel-cell technologies, fostering hydrogen demonstration projects worldwide. The anticipated integration of clean hydrogen into various sectors in the coming years signifies its importance as a complementary energy source, although specific applications across industries remain undefined. The paper provides a good reference on the gradual integration of hydrogen into the energy landscape, marking a significant step forward toward a cleaner, greener future.Item Open Access Battery thermal management for microchannel cooling system with scanning flow method(IEEE, 2025-02) Qin, Qing; Luo, Zhenhua; Luk, PatrickThe demand for high-performance electric vehicles has rapidly increased, necessitating rapid charging and efficient thermal battery management. High-energy-density batteries generate massive heat impacting performance, service life and safety. Thermal management plays a critical role in preserving battery integrity by regulating overall temperature and localized heat distribution, thus mitigating the risk of thermal runaway. Varies cooling technologies such as air, liquid, and multi-phase material cooling, have been utilized. However, minimizing the maximum temperature while maintaining temperature uniformity remains a critical challenge in battery thermal management. This paper introduces a novel microchannel cooling system with scanning flow for Li-ion batteries. Computational Fluid Dynamics (CFD) models are developed to investigate scanning flow cooling behavior. Parametric study examines the effects of battery numbers, valve switching frequency, and channel numbers on maximum and minimum temperatures, average temperature, and temperature differences. Furthermore, fluid analysis incorporates heat distribution and velocity behavior to study flow characteristics. Experimental analysis validates the cooling capability of the scanning flow method with a 0.17% error rate. The findings highlight scanning flow as an efficient method, enhancing temperature uniformity by 62.5% and reducing the average temperature difference by 92%. This presents a promising avenue for developing effective thermal management solutions for high-energy-density batteries.Item Open Access Biosensors for rapid detection of bacterial pathogens in water, food and environment(Elsevier, 2022-06-28) Nnachi, Raphael Chukwuka; Sui, Ning; Ke, Bowen; Luo, Zhenhua; Bhalla, Nikhil; He, Daping; Yang, ZhugenConventional techniques (e.g., culture-based method) for bacterial detection typically require a central laboratory and well-trained technicians, which may take several hours or days. However, recent developments within various disciplines of science and engineering have led to a major paradigm shift in how microorganisms can be detected. The analytical sensors which are widely used for medical applications in the literature are being extended for rapid and on-site monitoring of the bacterial pathogens in food, water and the environment. Especially, within the low-resource settings such as low and middle-income countries, due to the advantages of low cost, rapidness and potential for field-testing, their use is indispensable for sustainable development of the regions. Within this context, this paper discusses analytical methods and biosensors which can be used to ensure food safety, water quality and environmental monitoring. In brief, most of our discussion is focused on various rapid sensors including biosensors and microfluidic chips. The analytical performances such as the sensitivity, specificity and usability of these sensors, as well as a brief comparison with the conventional techniques for bacteria detection, form the core part of the discussion. Furthermore, we provide a holistic viewpoint on how future research should focus on exploring the synergy of different sensing technologies by developing an integrated multiplexed, sensitive and accurate sensors that will enable rapid detection for food safety, water and environmental monitoring.Item Open Access Characterisation of textile embedded electrodes for use in a neonatal smart mattress electrocardiography system(MDPI, 2021-02-02) Dore, Henry; Aviles-Espinosa, Rodrigo; Luo, Zhenhua; Anton, Oana; Rabe, Heike; Rendon-Morales, ElizabethHeart rate monitoring is the predominant quantitative health indicator of a newborn in the delivery room. A rapid and accurate heart rate measurement is vital during the first minutes after birth. Clinical recommendations suggest that electrocardiogram (ECG) monitoring should be widely adopted in the neonatal intensive care unit to reduce infant mortality and improve long term health outcomes in births that require intervention. Novel non-contact electrocardiogram sensors can reduce the time from birth to heart rate reading as well as providing unobtrusive and continuous monitoring during intervention. In this work we report the design and development of a solution to provide high resolution, real time electrocardiogram data to the clinicians within the delivery room using non-contact electric potential sensors embedded in a neonatal intensive care unit mattress. A real-time high-resolution electrocardiogram acquisition solution based on a low power embedded system was developed and textile embedded electrodes were fabricated and characterised. Proof of concept tests were carried out on simulated and human cardiac signals, producing electrocardiograms suitable for the calculation of heart rate having an accuracy within ±1 beat per minute using a test ECG signal, ECG recordings from a human volunteer with a correlation coefficient of ~ 87% proved accurate beat to beat morphology reproduction of the waveform without morphological alterations and a time from application to heart rate display below 6 s. This provides evidence that flexible non-contact textile-based electrodes can be embedded in wearable devices for assisting births through heart rate monitoring and serves as a proof of concept for a complete neonate electrocardiogram monitoring systemItem Open Access CNTs-added PMNT/PDMS flexible piezoelectric nanocomposite for energy harvesting application(Taylor and Francis, 2018-04-05) Promsawat, Napatporn; Promsawat, Methee; Janphuang, Phatthanapong; Beeby, Steve; Rojviriya, Catleya; Pakawanit, Phakkhananan; Pojprapai, Soodkhet; Luo, ZhenhuaThe flexible piezoelectric nanocomposites based on lead magnesium niobate titanate [Pb(Mg1/3Nb2/3)0.65Ti0.35O3; PMNT] particles in polydimethylsiloxane (PDMS) matrix were fabricated and characterized. PMNT powders are synthesized using the columbite precursor method. PMNT/PDMS flexible nanocomposites are then prepared by spin casting technique, where a small amount of carbon nanotubes (CNTs) is added into the PMNT/PDMS composite to enhance cross-links between PMNT particles and PDMS matrix. The phase and microstructure of the nanocomposite are investigated by using X-ray diffraction and scanning electron microscope (SEM). The electromechanical behavior is evaluated by using an autonomous pneumatic actuator. The flexible composite, occupying approximately 300 mm2, is capable of generating an open-circuit voltage (Voc) of 2.83 ± 0.24 V and a short-circuit current (Isc) signal of 0.33 ± 0.01 µA across 10 Ω resistor under mechanical load of 300 N. The generated electrical charges are 29026 pC. The relative dielectric constant is measured at 10 kHz and found to be 6.76 ± 1.15. The piezoelectric PMNT/PDMS composite can potentially be used in a variety of applications such as wearable sensors, actuators, and energy harvesting for converting kinetic energy into useful electrical energy.Item Open Access Cooling of concentrated photovoltaic cells - a review and the perspective of pulsating flow cooling(MDPI, 2023-03-18) Ibrahim, Khalifa Aliyu; Luk, Patrick Chi-Kwong; Luo, ZhenhuaThis article presents a review to provide up-to-date research findings on concentrated photovoltaic (CPV) cooling, explore the key challenges and opportunities, and discuss the limitations. In addition, it provides a vision of a possible future trend and a glimpse of a promising novel approach to CPV cooling based on pulsating flow, in contrast to existing cooling methods. Non-concentrated photovoltaics (PV) have modest efficiency of up to around 20% because they utilise only a narrow spectrum of solar irradiation for electricity conversion. Therefore, recent advances employed multi-junction PV or CPV to widen the irradiation spectrum for conversion. CPV systems concentrate solar irradiation on the cell’s surface, producing high solar flux and temperature. The efficient cooling of CPV cells is critical to avoid thermal degradation and ensure optimal performance. Studies have shown that pulsating flow can enhance heat transfer in various engineering applications. The advantage of pulsating flow over steady flow is that it can create additional turbulence and mixing in the fluid, resulting in a higher heat transfer coefficient. Simulation results with experimental validation demonstrate the enhancement of this new cooling approach for future CPV systems. The use of pulsating flow in CPV cooling has shown promising results in improving heat transfer and reducing temperature gradients.Item Open Access A critical role for host-derived cystathionine-β-synthase, in Staphylococcus aureus-induced udder infection(Elsevier, 2023-11-10) Fu, Shaodong; Yang, Bo; Gao, Yabin; Qiu, Yawei; Sun, Naiyan; Li, Zhi; Feng, Shiyuan; Xu, Yuanyuan; Zhang, Jinqiu; Luo, Zhenhua; Han, Xiangan; Miao, JinfengCystathionine-β-synthase (CBS) catalyzes the first step of the transsulfuration pathway. The role of host-derived CBS in Staphylococcus aureus (S. aureus)-induced udder infection remains elusive. Herein, we report that S. aureus infection enhances the expression of CBS in mammary epithelial cells in vitro and in vivo. A negative correlation is present between the expression of CBS and inflammation after employing a pharmacological inhibitor/agonist of CBS. In addition, CBS achieves a fine balance between eliciting sufficient protective innate immunity and preventing excessive damage to cells and tissues preserving the integrity of the blood-milk barrier (BMB). CBS/H2S reduces bacterial load by promoting the generation of antibacterial substances (ROS, RNS) and inhibiting apoptosis, as opposed to relying solely on intense inflammatory reactions. Conversely, H2S donor alleviate inflammation via S-sulfhydrating HuR. Finally, CBS/H2S promotes the expression of Abcb1b, which in turn strengthens the integrity of the BMB. The study described herein demonstrates the importance of CBS in regulating the mammary immune response to S. aureus. Increased CBS in udder tissue modulates excessive inflammation, which suggests a novel target for drug development in the battle against S. aureus and other infections.Item Open Access Dataset relating to "Permeability measurements for the Investigation of a practical approach to the measurement of magnetic permeability of ferrofluids"(Cranfield University, 2024-10-02) Lakshminarayanan, Venkatasubramanian; Qin, Qing; Geng, Jiaxin; Luo, ZhenhuaFerrofluids are colloids of magnetic particles in a fluid. Ferrofluids have wide range of application in engineering and medicine. Their relative magnetic permeability is one of the important parameters that needs to be measured. This dataset contains the measurements observed in the process of using an existing technique to measure magnetic permeability with a solenoid and LCR meter to identify experimental factors relevant to the accuracy of measurement.Item Open Access Decision support system for sustainable hydrogen production: case study of Saudi Arabia(Elsevier, 2025-02) Kaheel, Sultan; Fallatah, Gasem; Luk, Patrick; Ibrahim, Khalifa Aliyu; Luo, ZhenhuaThe global energy sector is undergoing a transition towards sustainable sources, with hydrogen emerging as a promising alternative due to its high energy content and clean-burning properties. The integration of hydrogen into the energy landscape represents a significant advancement towards a cleaner, greener future. This paper introduces an innovative decision support system (DSS) that combines multi-criteria decision-making (MCDM) and decision tree methodologies to optimize hydrogen production decisions in emerging economies, using Saudi Arabia as a case study. The proposed DSS, developed using MATLAB Web App Designer tools, evaluates various scenarios related to demand and supply, cost and profit margins, policy implications, and environmental impacts, with the goal of balancing economic viability and ecological responsibility. The study's findings highlight the potential of this DSS to guide policymakers and industry stakeholders in making informed, scalable, and flexible hydrogen production decisions that align with sustainable development goals. The novel DSS framework integrates two key influencing factors technical and logistical by considering components such as data management, modeling, analysis, and decision-making. The analysis component employs statistical and economic methods to model and assess the costs and benefits of eleven strategic scenarios, while the decision-making component uses these results to determine the most effective strategies for implementing hydrogen production to minimize risks and uncertainties.Item Open Access Delineating mastitis cases in dairy cows: development of an IoT-enabled intelligent decision support system for dairy farms(IEEE, 2024-04-18) Khan, Mohammad Farhan; Thorup, Vivi Mørkøre; Luo, ZhenhuaMastitis, an intramammary bacterial infection, is not only known to adversely affect the health of a dairy cow but also to cause significant economic loss to the dairy industry. The severity and spread of mastitis can be restrained by identifying the early signs of infection in the cows through an intelligent decision support system. Early intervention and control of infection largely depend on the availability of on-site high throughput machinery, which can analyze milk samples regularly. However, due to limited resources, marginal and small farms usually cannot afford such high-end machinery, hence, the financial loss in such farms due to mastitis may become significant. To overcome such limitations, this article proposes a low-complexity yet affordable automated system for accurate prediction of early signs of clinical mastitis infection in dairy cows. In this work, behavioral data collected through Internet of Things (IoT)-enabled wearable sensors for cows is utilized to develop a support vector machine (SVM) model for the daily prediction of mastitis cases in a dairy farm. The dataset from the research herd utilizes the information of 415 cows collected in the span of 4.75 years in which 75 cows had mastitis. In addition to relevant behavioral features, other statistically significant features, such as daily milk yield, lactation period, and age are also utilized as features. Our study indicates that the SVM model comprising a subset of behavioral and nonbehavioral features can deliver a mastitis prediction accuracy of 89.2%.Item Open Access Effects of frequency on electrical fatigue behavior of ZnO-modified Pb(Mg1/3Nb2/3)0.65Ti0.35O3 ceramics(Elsevier, 2017-07-08) Promsawat, Methee; Promsawat, Napatporn; Wong, Jenny W.; Luo, Zhenhua; Pojprapai, Soodkhet; Jiansirisomboon, SukandaThis work aims to study the effects of frequency on the electrical fatigue behavior of ZnO-modified Pb(Mg1/3Nb2/3)0.65Ti0.35O3 (PMNT) ceramics. Changes in microstructures, ferroelectric and piezoelectric properties of the ceramics at bipolar electrical fatigue frequencies of 5, 10, 50 and 100 Hz were observed. The thickness of damaged surface of the ceramics decreased with increasing frequency. The degradation of properties of the ceramics fatigued at low frequency was greater than those fatigued at high frequency. The degradation by electrical fatigue at lower frequencies, 5 and 10 Hz, could be caused by the effects of both field screening and domain pinning, while at higher frequencies the fatigue was mainly a result of the field screening effect. The fatigue properties of ZnO-modified PMNT ceramics was compared to Pb-based and Pb-free ferroelectric ceramics. It was found that the fatigue endurance of ZnO-modified PMNT ceramic was greater than that of hard PZT ceramic but less than that of Pb-free ferroelectric ceramic.Item Open Access Effects of temperature on aging degradation of soft and hard lead zirconate titanate ceramics(Elsevier, 2017-04-26) Promsawat, Methee; Marungsri, Boonruang; Promsawat, Napatporn; Janphuang, Pattanaphong; Luo, Zhenhua; Pojprapai, SoodkhetThis paper aims to study the effects of heat treatment temperatures on the aging degradation of piezoelectric properties, i.e. piezoelectric coefficient (d33) and planar electromechanical coupling factor (kp), in soft and hard PZT ceramics. Aging degradations of d33 and kp of the samples were measured for 192 h prior to heat treatments. The samples were then treated at various temperatures equivalent to 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8 times of the materials' Curie temperatures. Aging degradations of d33 and kp of the heat-treated samples were observed continuously for 1128 h. The piezoelectric properties of the un-treated samples gradually decreased with aging time. Attenuation of d33 and kp in the samples immediately after heat treatment increased with increasing heat treatment temperature. Moreover, aging degradation rate and relaxation time of the samples measured after heat treatments increased with increasing heat treatment temperature. Comparing to hard PZT ceramics, soft PZT demonstrated greater change of d33 and kp immediately after heat treatments. Soft PZT also showed greater aging rate and aging time than those of hard PZT. From the overall results, it can be concluded that both material type and heat treatment temperature have effects on aging behaviors of PZT materials. Aging degradation was more pronounced in soft PZT and the samples treated at high temperatures. The observed aging behaviors of PZT materials were explained by the interaction between domains and defects of oxygen vacancies that leads to volume, domain and grain boundary effects.Item Open Access Energy harvesting technologies on high-speed railway infrastructure: review and comparative analysis of the potential and practicality(Elsevier, 2025-02-01) Sun, Wenjing; Thompson, David J.; Yurchenko, Daniil; Zhao, Dong; Luo, Zhenhua; Khan, IrfanA comprehensive quantitative analysis is provided of the potential applications of energy harvesting (EH) technologies tailored to high-speed railway infrastructure. The study compares the various energy sources within railway infrastructure and identifies suitable EH technologies. Feasible designs and scales of EH are assessed based on the installation location; the overall power availability and energy yield are compared for a notional high-speed railway. For resonant EH devices an assessment is also given of the optimal tuning frequency. Vibration-based EH, when applied to the track or bridge structures, can provide sufficient power for individual low-power sensors; however, its output is insufficient for higher-power applications or for data transmission unless energy storage devices are incorporated. Despite the elevated noise levels generated by high-speed trains, the energy available from this acoustic source is negligible and impractical for EH. Small vertical axis wind turbines installed close to the track and driven by passing trains show great potential, capable of harvesting several orders of magnitude more energy than vibration-based EH. Solar photovoltaic panels can generate significantly more energy than other methods, although their output is confined to daylight conditions and is contingent upon weather conditions.Item Open Access Evaluation of screen-printing techniques for embedding ECG sensors in medical devices(IEEE, 2020-12-28) Dore, Henry; Aviles-Espinosa, Rodrigo; Luo, Zhenhua; Anton, Oana; Rabe, Heike; Rendon-Morales, ElizabethHeart rate monitoring is the most important indicator to evaluate the clinical status of a newborn during birth. Approximately 90% of newborn infants make the transition from the intrauterine to extra uterine environment without major complications; however, the remaining 10% of newborn infants require assistance during this transition. Heart rate monitoring is required for guiding further interventions in the event of complications such as the need for resuscitation. In this work we evaluate the suitability of embedding electrometer-based-amplifier sensors employing novel screen-printing techniques into medical devices. We compare our results with traditional copper based wired electrodes. Our implementation was able to acquire electrocardiogram with enough signal to noise ratio, suitable for heart rate detection with a 1% loss of heart rate accuracy, compared with the copper-based electrodes. Our device has the potential to be embedded in devices for assisting births though heart rate monitoring.Item Open Access FABP4-mediated lipid droplet formation in Streptococcus uberis-infected macrophages supports host defence(BMC - Springer, 2022-11-12) Wan, Zhixin; Fu, Shaodong; Wang, Zhenglei; Xu, Yuanyuan; Zhou, Yuanyuan; Lin, Xinguang; Lan, Riguo; Han, Xiangan; Luo, Zhenhua; Miao, JinfengFoamy macrophages containing prominent cytoplasmic lipid droplets (LDs) are found in a variety of infectious diseases. However, their role in Streptococcus uberis-induced mastitis is unknown. Herein, we report that S. uberis infection enhances the fatty acid synthesis pathway in macrophages, resulting in a sharp increase in LD levels, accompanied by a significantly enhanced inflammatory response. This process is mediated by the involvement of fatty acid binding protein 4 (FABP4), a subtype of the fatty acid-binding protein family that plays critical roles in metabolism and inflammation. In addition, FABP4 siRNA inhibitor cell models showed that the deposition of LDs decreased, and the mRNA expression of Tnf, Il1b and Il6 was significantly downregulated after gene silencing. As a result, the bacterial load in macrophages increased. Taken together, these data demonstrate that macrophage LD formation is a host-driven component of the immune response to S. uberis. FABP4 contributes to promoting inflammation via LDs, which should be considered a new target for drug development to treat infections.Item Open Access Floating PV systems as an alternative power source: case study on three representative islands of Indonesia(MDPI, 2024-02-05) Esparza, Ignacio; Olábarri Candela, Ángela; Huang, Luofeng; Yang, Yifeng; Budiono, Chayun; Riyadi, Soegeng; Hetharia, Wolter; Hantoro, Ridho; Setyawan, Dony; Utama, I Ketut Aria Pria; Wood, Tim; Luo, ZhenhuaFloating solar renewable energy is of enormous potential in Indonesia. This paper presents a comprehensive study of the design of Floating Photovoltaic (FPV) systems with Battery Energy Storage Systems (BESS) for three islands in Indonesia. These islands represent three typical scenarios in Indonesia (a) using a national grid powered by fossil fuel generators, (b) using a local grid powered by diesel generators, and (c) no grid at all. In-person surveys were conducted at these islands to collect data, and then FPV and BESS were designed to meet the demands of each island. Subsequently, the systems’ energy simulations were conducted using the System Advisor Model, demonstrating daily energy demand and supply in hour variation. Based on the results, a series of sustainability analyses were created from the aspects of economics, society, and the environment. The economic analysis demonstrated cost savings by using FPV to replace contemporary energy methods. The social analysis provides valuable insights into the local community, forming a demographic profile and obtaining perceptions and opinions regarding the new energy approach. The environmental analysis quantifies the potential CO2 emissions. Overall, the work provides valuable insights into the roadmap for implementing floating solar technologies in Indonesia which can also inform global ocean-based solar energy developments.Item Open Access Floating solar power loss due to motions induced by ocean waves: an experimental study(Elsevier, 2024-11-15) Huang, Luofeng; Yang, Yifeng; Khojasteh, Danial; Ou, Binjian; Luo, ZhenhuaWhilst there is an interest in floating solar energy systems in coastal and offshore regions to utilise available sea space, they are subject to ocean waves that introduce constant momentum. Consequently, solar panels undergo periodic motions with the waves, causing a continuous change in tilt angle. The tilt angle variation is a sub-optimal process and leads to a loss of energy harnessing efficiency. To investigate this phenomenon, the present study innovatively installed a solar simulator on top of a wave tank. The solar simulator was used to generate high-strength light beams, under which, a floating solar unit was subject to periodic incident waves. Wave-induced motions to the solar system as well as the output power were measured. A systematic analysis of the results indicated that a floating solar unit can have significantly lower power output in waves, compared to its calm-water counterpart. An evident link was established between the wave-induced power loss and the wave-induced rotational movement of the panel. An empirical equation was derived which shows the power loss is predictable through the rotational amplitude. The results also highlight the importance of implementing wave attenuation technologies such as breakwaters to minimise wave-induced motions to floating solar systems. Overall, this research presents a novel experimental approach to assess the difference of floating solar power in ocean-wave versus calm-water scenarios, providing valuable insights for future solar projects on the ocean.Item Open Access Floating solar wireless power transfer system for electric ships: design and laboratory tests(Elsevier, 2025-05-15) Ibrahim, Khalifa Aliyu; Maréchal, Timothé Le; Luk, Patrick; Qin, Qing; Huang, Luofeng; Xie, Ying; Verdin, Patrick; Luo, ZhenhuaThe maritime industry is under increasing pressure to decarbonise, presenting an important pathway of transforming the power systems from conventional marine fuels to electric-based. This study proposes an innovative solution to support maritime decarbonisation through the integration of a floating solar clean energy harnessing and wireless power transfer (WPT) technology for electric vessels. The paper presents the design and experimental tests of the integrated system specifically, based on a model of an electric yacht. This study provides an in-depth analysis of application of floating solar to provides an off-grid wireless power transfer system that can scale for larger vessels such as ferries. The off-grid modularity proposed enables scalable, flexible, and sustainable energy delivery for maritime applications and decarbonisation with specific attention to challenges in WPT alignment and environmental condition. Simulations using ANSYS Maxwell were performed to model the magnetic field interactions and ascertain the optimal power transfer efficiency. Subsequently, a reduced-scale prototype system was designed, built and tested in a wave tank. The experimental results demonstrated efficient wireless charging with an average efficiency of 82 %, and the docking system proved effective in maintaining alignment even when the ship has wave-induced motions. The findings support the feasibility of using floating solar WPT systems for maritime vessels and pave the way to larger-scale studies.Item Open Access Harnessing energy for wearables: a review of radio frequency energy harvesting technologies(MDPI, 2023-07-31) Nwalike, Ezekiel Darlington; Ibrahim, Khalifa Aliyu; Crawley, Fergus; Qin, Qing; Luk, Patrick; Luo, ZhenhuaWireless energy harvesting enables the conversion of ambient energy into electrical power for small wireless electronic devices. This technology offers numerous advantages, including availability, ease of implementation, wireless functionality, and cost-effectiveness. Radio frequency energy harvesting (RFEH) is a specific type of wireless energy harvesting that enables wireless power transfer by utilizing RF signals. RFEH holds immense potential for extending the lifespan of wireless sensors and wearable electronics that require low-power operation. However, despite significant advancements in RFEH technology for self-sustainable wearable devices, numerous challenges persist. This literature review focuses on three key areas: materials, antenna design, and power management, to delve into the research challenges of RFEH comprehensively. By providing an up-to-date review of research findings on RFEH, this review aims to shed light on the critical challenges, potential opportunities, and existing limitations. Moreover, it emphasizes the importance of further research and development in RFEH to advance its state-of-the-art and offer a vision for future trends in this technology.Item Open Access High force compression mode to shear mode piezoelectric energy harvesting(IEEE, 2024-02-05) Crawley, Fergus J. E.; Luo, ZhenhuaThis paper evaluates a novel design of a bridge shear-force structure used to transfer large compressive loads into shear loads on the surface of a piezo disc. The wave/crinkle design can increase the overall number of bridges in a concentric orientation to the circumference with the aim of producing multiple shear force pinch points, changing the shear mode extension path along the piezo discs' axial plane, allowing for tunability, and increasing electrical energy output of a Piezoelectric Energy Harvester (PEH).