Reduced Maintenance Requirements Research Articles

Effects of nanoceramic particle size and content on the wear resistance of micro-arc oxidation coatings for 2A12 aluminum alloy

The 2A12 aluminum alloy, renowned for its exceptional mechanical properties, encounters significant limitations in applications involving abrasive environments or frequent contact with other surfaces due to its inadequate wear resistance. This shortcoming substantially reduces the service life of components and escalate maintenance costs, highlighting the urgent need for advanced surface modification techniques. This study meticulously investigates the influence of nanoceramic particle size and content on the wear resistance of micro-arc oxidation (MAO) coatings, a surface modification technique renowned for forming dense, adherent ceramic layers on aluminum alloys. The systematic experimentation revealed that the incorporation of 150 nm α-Al2O3 nanoparticles into the MAO matrix achieves an optimal dispersion, leading to a substantial enhancement in wear resistance. The sample with a 5 g/L concentration of 150 nm α-Al2O3 nanoparticles doping in the MAO electrolyte demonstrated the lowest mass loss, underscoring its enhanced wear resistance. The enhanced microstructure, enriched with hard ceramic phases such as α-Al2O3 and mullite, plays a pivotal role in withstanding wear. Moreover, this study identified that an optimal balance of surface roughness and coating thickness is essential for achieving enhanced wear resistance. The findings of this research provide a strategy for the design of wear-resistant coatings tailored for high-performance applications across aerospace, automotive, and general engineering industries. By optimizing the particle size and concentration in MAO coatings, this study paves the way for the development of durable materials capable of thriving in demanding environments, thereby extending the service life and reducing maintenance requirements of components.

Advanced materials and deepwater asset life cycle management: A strategic approach for enhancing offshore oil and gas operations

Offshore oil and gas operations are inherently complex, requiring a strategic approach to asset life cycle management to ensure efficiency, safety, and environmental sustainability. This review explores the use of advanced materials in deepwater asset management, highlighting their role in enhancing operational performance and longevity. The review begins by discussing the challenges associated with deepwater operations, including harsh environmental conditions, high pressures, and corrosive fluids. These challenges necessitate the use of advanced materials that can withstand such conditions while maintaining structural integrity and operational efficiency. The review then outlines the strategic approach to asset life cycle management, emphasizing the importance of integrating advanced materials into design, construction, and maintenance processes. This approach includes the selection of materials based on their performance characteristics, compatibility with existing infrastructure, and cost-effectiveness. Furthermore, the review discusses the benefits of using advanced materials in deepwater asset management, including improved corrosion resistance, enhanced structural strength, and reduced maintenance requirements. These benefits translate into increased operational uptime, reduced downtime for repairs, and overall cost savings. Finally, the review concludes by highlighting the importance of collaboration between industry stakeholders, including operators, manufacturers, and research institutions, to drive innovation in advanced materials and deepwater asset management. By embracing a strategic approach and leveraging advanced materials, offshore oil and gas operations can achieve higher levels of efficiency, safety, and sustainability. Keywords: Advanced Materials, Deepwater Asset, Strategic Approach, Life Cycle Management, Oil and Gas Operations.

Technological innovations and optimized work methods in subsea maintenance and production

Subsea maintenance and production represent critical aspects of offshore operations, vital for sustaining energy production and ensuring operational efficiency. However, these endeavors face numerous challenges, including the complexities of deepwater environments, harsh weather conditions, and the high costs associated with traditional maintenance methods. To address these challenges, this paper explores the integration of technological innovations and optimized work methods in subsea operations. Technological innovations play a pivotal role in revolutionizing subsea maintenance and production. Remote monitoring and control systems enable real-time data collection and decision-making, enhancing operational visibility and efficiency. Autonomous underwater vehicles (AUVs) offer the capability to conduct inspections and repairs in remote and hazardous environments, reducing human intervention and associated risks. Robotics and automation further streamline maintenance tasks, improving accuracy and reducing downtime. Advanced materials and coatings enhance equipment durability and corrosion resistance, prolonging asset lifecycles and reducing maintenance requirements. In parallel, optimized work methods offer strategic approaches to enhance subsea operations' effectiveness. Predictive maintenance strategies leverage data analytics and machine learning to anticipate equipment failures, enabling proactive interventions and minimizing downtime. Condition-based monitoring facilitates real-time assessment of asset health, enabling timely maintenance interventions and cost savings. Integrated asset management systems provide holistic insights into asset performance and facilitate informed decision-making. Lean operations and continuous improvement methodologies further optimize workflows, driving operational excellence and cost efficiency. Through case studies and industry examples, this paper highlights the successful implementation of technological innovations and optimized work methods in subsea maintenance and production. Furthermore, it explores future trends, regulatory considerations, and the importance of industry collaborations in shaping the future of subsea operations. Ultimately, the integration of these approaches offers a pathway towards enhanced operational efficiency, reduced costs, and sustainable subsea operations. Keywords: Technological Innovations, Optimized Work Methods, Subsea Maintenance and Production.

Impact of speed and axle load on the static and dynamic mechanical behavior of the ballast bed laying under sleeper pads

With the evolution of railway infrastructure towards accommodating higher speeds and heavier loads, the under sleeper pad (USP) has emerged as a critical component in mitigating the deterioration of the ballast bed and reducing maintenance requirements. This study aims to enhance the understanding of the suitability of the USP for railway lines and to investigate the static and dynamic mechanical behaviors of the ballast bed (with USP) under the train load. To achieve this, the study conducts on-site tests and employs the discrete element method-multi-flexible body dynamics (DEM-MFBD) coupling analysis to develop a three-dimensional high-fidelity model of the ballast bed (with USP). This comprehensive analysis assesses the impact of varying train speeds and axle loads on the mechanical properties of the ballast bed with the USP, integrating both macroscopic and microscopic perspectives. The results show that there is an 8.54% reduction in longitudinal resistance of the ballast bed (with USP) compared to the ballast bed (without USP), yet it still fulfils the requirements of heavy railway lines. The ballast bed (with USP) exhibits significant improvements in vibration-damping performance, with the wheel-rail vertical force showing a reduction of 8.71% relative to the ballast bed (without USP). This suggests a potential extension of the track structure's lifespan. An increase in train speed markedly influences the vibration levels of the ballast bed (with USP), leading to an increase in ballast bed acceleration by 119.39%. The increase in train axle load demonstrates a minor effect on the plastic deformation of the ballast bed, indicating the ballast bed (with USP)'s capability to accommodate heavier axle load trains.

Performance of Soil-bearing Spread Footings Supporting Highway Structures

Background Soil-bearing spread footings (SBSF) are emerging as an increasingly attractive option for supporting highway structures. SBSF offers numerous benefits compared to deep foundations, including cost-effectiveness, accelerated construction, straightforward design, environmentally friendly characteristics, and reduced maintenance requirements. Objective The primary objective of this study is to assess the performance of highway structures that SBSF supports at four specific locations in Ohio. The findings from this assessment will serve as valuable recommendations for the future application of spread footings while identifying potential usage constraints. Methods The project team conducted a comprehensive review of documented performance data, assessed the effectiveness of existing footings, and compared these assessments against established structural performance criteria. Additionally, the team analyzed calculated settlements, provided an estimate of acceptable structural settlement, compared measured settlements with predicted values, and examined the relationship between performance and soil conditions. Results The data gathered, and field assessments conducted at all four sites encompassed in this investigation affirm that SBSF structures function as designed, displaying no signs of settlements or cracks associated with rideability. Both measured and calculated settlements fall within acceptable tolerances. While all structures exhibited acceptable levels of differential settlement, one encountered a differential settlement of approximately 54 mm between substructures, attributed to cohesive soil (A-6) in deeper layers. Conclusion SBSF structures were constructed by the manuals and guidelines established by the Ohio Department of Transportation (ODOT) and exhibited satisfactory performance. This paper also offers recommendations for settlement monitoring methods and plan notes that should be incorporated into the Ohio Department of Transportation's practices.

ADVANCED MATERIALS FOR SUSTAINABLE CONSTRUCTION: A REVIEW OF INNOVATIONS AND ENVIRONMENTAL BENEFITS

The field of sustainable construction has witnessed a paradigm shift with the advent of advanced materials that not only enhance structural performance but also contribute significantly to environmental conservation. This paper provides a comprehensive review of innovations in advanced materials for sustainable construction, elucidating their environmental benefits. In recent years, researchers and industry professionals have focused on developing materials that reduce the environmental impact of construction activities. This review explores a myriad of advanced materials, including but not limited to high-performance concrete, green composites, and recycled polymers. High-performance concrete formulations integrate advanced admixtures and supplementary cementitious materials, resulting in structures with superior strength and durability while minimizing resource consumption. Green composites, composed of natural fibers and bio-based resins, have emerged as a sustainable alternative to traditional construction materials. These composites not only exhibit impressive mechanical properties but also possess a reduced carbon footprint, aligning with the principles of eco-friendly construction practices. Additionally, the utilization of recycled polymers derived from post-consumer waste in construction materials represents a significant stride towards circular economy principles, addressing concerns related to plastic pollution. Environmental benefits of these advanced materials are multifold. The reduction in raw material extraction, energy consumption, and greenhouse gas emissions associated with their production contribute to a more sustainable construction industry. Furthermore, the enhanced durability of structures built with these materials leads to extended service life and reduced maintenance requirements, further mitigating the environmental impact over the life cycle. The integration of advanced materials in sustainable construction not only elevates the performance of structures but also aligns with global efforts to minimize the ecological footprint of the built environment. This review serves as a valuable resource for researchers, practitioners, and policymakers seeking insights into the latest innovations and environmental advantages of advanced materials in the realm of sustainable construction.
 Keywords: Materials, Sustainable Construction, Innovation, Environmental, Advanced, Review.

Ash conveying system upgrade from hydraulic to pneumatic system in a 550MW coal-fired power plant in Taiwan

The paper presents a comprehensive study on the ash handling system upgrade from a hydraulic conveying system to a pneumatic system in a 550 MW coal-fired power plant located in Taiwan. The ash pond used to dispose of ash from the economizer and air preheater is almost full due to having been in service for more than forty years. An alternative location to dispose of the ash is sought. The design process of finding the new location and the equipment to be used is explored. Some options for the new economizer and air preheater ash disposal site, including building a new silo or using an existing silo, are taken into consideration in terms of design, cost, and timing of execution. The project’s execution procedure is reviewed, taking into account aspects of system integration, equipment installation, and commissioning. The primary objective of this paper is to detail the design, implementation, and outcomes of the ash handling system upgrade. This upgrade is accomplished in an effort to enhance operational efficiency, reduce maintenance requirements, and improve environmental compliance. The study explores the motivations behind adopting pneumatic conveying technology, focusing on its advantages over hydraulic systems, such as reduced maintenance needs and improved dust control. The case study provides insight into the lesson learned and recommendations for similar ash conveying system upgrades in other coal-fired power plants.

Bir Havacılık Elastoplastik Yapısal Delikli Silindirik Bileşenin Döngüsel Mekanik Yük Altında COMSOL Multiphysics ve Taguchi Metodu Optimizasyonu ile Yorulma Analizi

This research study focuses on the fatigue behavior of an aerospace elastoplastic cylindrical structural component with a hole subjected to cyclic mechanical loads. In the demanding operational environment of aerospace applications, the structural components, particularly those with stress concentrators like holes, experience cyclic loading conditions, leading to fatigue failure over time. The key objective of this study is to gain insights into this fatigue behavior, and to develop an optimized set of design and operational parameters that can enhance the fatigue performance of these components. Utilizing the robust finite element analysis capabilities of COMSOL Multiphysics, a comprehensive model of the elastoplastic cylindrical component is developed. The model captures the intricate effects of the hole, a typical stress raiser, on the fatigue performance under various cyclic mechanical loading conditions. A detailed fatigue analysis is then performed using this model, providing valuable insights into the fatigue life and failure patterns of the component. To enhance the fatigue performance, the Taguchi method, a statistical approach, is employed. This method helps to identify and optimize the key design and operational parameters influencing the fatigue life. The parameters are optimized based on their signal-to-noise ratio, with an aim to maximize the fatigue life and ensure the structural integrity of the component under operational cyclic loads. The findings of this research hold significant implications for the design and manufacturing of aerospace structural components, with potential benefits of improved safety, enhanced durability, and reduced maintenance requirements. However, the results' applicability might be limited by the complexity of real-world operational conditions and the assumptions made in the simulation model. Future studies can validate and enhance these results by incorporating more complex loading scenarios and real-world case studies.

Improved Design For Horizontal Axis Wind Turbine Blades With Winglets

The horizontal axis wind turbine blades are modified to enhance the turbine's aerodynamic performance. The performance of the modified geometry was evaluated by comparing the lift, drag and torque findings to the same propeller with a straight leading edge. The symmetrical airfoil of NACA 0012 was chosen for the turbine blade profiles. The computational fluid dynamics (CFD) simulation was performed using the shear stress transport (SST) k-ω turbulence model to capture the vortical structures for the inlet wind speed of 20 m/s. From the simulation results, it has been shown that the four blades with winglets at 15° angle of attack (AoA) orientation turbine have demonstrated the highest aerodynamic performance. It produces the lowest aerodynamic drag and the most increased torque for turbine rotations, which, in return, carries many economic advantages such as energy savings, low impact on the environment, reduced maintenance requirements, and less noise.Keywords: Aerodynamics, CFD, drag, horizontal axis wind turbine, lift, winglets

Influence of exponential heat source, variable viscosity and shape factor on a hybrid nanofluid flow over a flat plate when thermal radiation and chemical reaction are significant

The significance of hybrid nanofluid flow over a flat plate lies in its ability to enhance heat transfer, improve energy efficiency, enable temperature control, and provide surface protection. For instance, hybrid nanofluids can provide a protective coating on the surface of a flat plate due to the presence of nanoparticles. This coating can offer improved corrosion resistance, erosion resistance, and anti-fouling properties. Consequently, it can extend the lifespan of the flat plate and reduce maintenance requirements. In this study, we examined how several characteristics, such as variable viscosity, chemical reaction, thermal radiation and shape factor of nanoparticles, affect the flow of a hybrid nanofluid (H[Formula: see text]) through a flat plate. The equations required to represent the problem have been turned into a system of nonlinear ordinary differential equations, and this system has been unraveled by means of the bvp4c solver. Outcomes are provided for three instances related to shape factor i.e. Platelet, Cylinder and Spherical. Using Multiple Linear Regression (MLR), we investigated how physical parameters of concern together with friction factor, are affected by a variety of parameters. It is remarked that the fluid’s velocity lessens as the variable viscosity parameter enhances. It is discovered that the temperature profile increases with the rise in exponential heat source parameter ([Formula: see text]). It is discovered that when [Formula: see text], the Nusselt number declines by 0.03588 (Platelet shape), 0.03562 (Cylinder shape), and 0.03489 (Spherical shape). It has been noted that magnetic field parameter (Mg) reduces the coefficient of skin friction. At [Formula: see text], the skin friction coefficient is seen to drop at a rate of 1.15018 (Platelet shape), 1.14871 (Cylinder shape), and 1.14476 (Spherical shape). There is an enhancement in the Sherwood number with the rise in Schmidt number (St) and chemical reaction parameter (Cr). At [Formula: see text] the Sherwood number is seen to rise at a rate of 0.248303 (Platelet shape), 0.248344 (Cylinder shape), and 0.248447 (Spherical shape). Furthermore, it is detected that the fluid’s temperature rises as the thermal radiation parameter enhances and the entropy generation increases as the variable viscosity parameter increases.

Parametric Reduced Order Model of a Gas Bearings Supported Rotor

Abstract Gas bearings use pressurized gas as a lubricant to support and guide rotating machinery. These bearings have a number of advantages over traditional lubricated bearings, including higher efficiency in a variety of applications and reduced maintenance requirements. However, they are more complex to operate and exhibit nonlinear behaviors. This paper presents a parametric hyper reduced order model (h-ROM) of a gas bearings supported rotor enabling to speed up the computations up to a factor 100 while preserving satisfactory accuracy. A Galerkin projection setting is employed to reduce the dimension of the governing equations and the nonlinear terms are efficiently tackled with a sparse sampling technique. The performances of the h-ROM are compared to a high fidelity model both in terms of accuracy and computation time, demonstrating the potential for future anomaly detection applications.

A Review of Power Transfer Systems for Light Rail Vehicles: The Case for Capacitive Wireless Power Transfer

Light rail vehicles (LRVs) are increasingly in demand to sustainably meet the transport needs of growing populations in urban centres. LRVs have commonly been powered from the grid by direct-contact overhead catenary systems (OCS); however, catenary-free direct-contact systems, such as via a “hidden rail”, are popular for new installations. Wireless power transfer (WPT) is an emerging power transfer (PT) technology for e-transport with several advantages over direct contact systems, including improved aesthetics and reduced maintenance requirements; however, they are yet to be utilised in LRV systems. This paper provides a review of existing direct-contact and wireless PT technologies for LRVs, followed by an in-depth critical assessment of inductive power transfer (IPT) and capacitive power transfer (CPT) technologies for LRVs. In particular, the feasibility and advantages of CPT for powering LRVs are presented, highlighting the efficacy of CPT with respect to power transfer capability, safety, and other factors. Finally, limitations and recommendations for future works are identified.

Numerical investigation of a geothermal thermoelectric generator using gravity heat pipe structure

Geothermal energy is a kind of clean energy with a large amount of energy. Some energy problems can be solved by collecting its heat and using thermoelectric generators. This paper studies a thermoelectric generator that utilizes shallow geothermal energy to generate electricity. Its physical model is built including heat exchanger, generator and radiator. The heat exchanger adopts gravity heat pipe, the generator adopts thermoelectric module, and the radiator adopts fin. To improve its efficiency, the effects of different working fluids and heat pipe diameters on heat transfer and the effects of different numbers of thermoelectric modules on power generation are considered. This paper considers the effects of different working fluids, heat pipe diameters and different numbers of thermoelectric modules on heat transfer and power generation. The study found that the heat transfer effect of the heat pipe can be better when water is used as the working fluid and the large pipe diameter. Properly increasing the number of TEMs can improve the power generation. This generator does not require energy consumption and moving equipment, thus reducing maintenance requirements.

Design and development of green energy microgrids for Agro-processing to minimize food waste in smallholder farms

This study explores the design, deployment, and evaluation of a green energy microgrid for Agro-processing in smallholder farms, integrating renewable energy sources such as solar photovoltaics, wind turbines, and biomass. The primary goal was to address the energy challenges that smallholder farmers face, particularly in relation to post-harvest losses, operational costs, and environmental sustainability. The study utilized a hybrid system that combined energy generation from solar, wind, and biomass, supported by lithium-ion batteries for storage, to ensure a stable power supply throughout the year. The results demonstrated that the microgrid was effective in meeting the energy needs of Agro-processing units, including milling, drying, and cooling. Energy generation from solar and biomass was highest during peak harvest months, while wind energy provided a consistent, though smaller, contribution. The microgrid enabled significant reductions in post-harvest losses, averaging around 40% across the year, by ensuring timely drying and cooling of agricultural products. Moreover, the system achieved a 74–76% reduction in operational costs compared to traditional diesel generators, largely due to the elimination of fuel costs and reduced maintenance requirements. In terms of environmental impact, the microgrid reduced greenhouse gas emissions by more than 70%, contributing to the broader goals of climate change mitigation and sustainable agriculture. The use of biomass also contributed to waste reduction by converting agricultural residues into energy, supporting a circular economy model. The study further highlighted the socio-economic benefits of the microgrid, including job creation, local economic growth, and the potential for energy surplus sales to neighboring communities. These findings suggest that green energy microgrids are a viable, sustainable solution for improving energy access and food security in rural agricultural settings

Long-Range Wireless Power Drive Using Magnetic Extender

This article proposes and implements a long-range wireless power drive (WPD) system using a magnetic extender, which can be promisingly applied in underground pipeline transportations and in-pipe robots. Generally, the underground pipeline transportation networks usually rely on the power grid and control system to regulate the flow rate. Nonetheless, such wired pipeline networks mainly suffer from increasing the construction cost, maintenance difficulty, and system complexity. By using pulse frequency modulation, the development of the proposed long-range WPD enables a wireless pipeline network for flow rate regulation, which has the advantages of robust structure and reduced maintenance requirements. With the addition of a designed magnetic extender, the circuit network can offer an excellent fault tolerance capability for underground sensor-free WPD while maintaining a high transmission efficiency. Significantly, the use of a magnetic extender will cause no inconvenience thanks to its underground deployment. Accordingly, the system efficiency of a full-scale prototype can reach around 89.1% for the meter-range WPD. Theoretical analysis, computational simulation, and prototype experimentation are given to verify the feasibility of the proposed long-range WPD using a magnetic extender.

A cycloidal magnetic gear with a novel flux shield (“moon”) achieving higher torque density and lower unbalanced electromagnetic forces

Magnetic gears’ numerous potential advantages, such as contactless operation, reduced maintenance requirements, lack of lubrication, and inherent overload protection, have led to significant interest in the technology. The cycloidal magnetic gear (CyMG) is an enticing option for applications requiring high gear ratios. CyMGs do not require the modulators used in coaxial magnetic gears, but CyMGs have disadvantages, including counterproductive torque developed in the larger air gap region and unbalanced magnetic forces, which must be supported by the bearings. This paper introduces a novel “moon” structure, which serves as a flux shield, for CyMGs. The moon is made out of ferromagnetic material and is located in the larger region of the air gap. The moon increases torque density by providing a leakage path for the flux that would otherwise create counterproductive torque. The moon also reduces the unbalanced magnetic forces. This structure’s benefits are investigated using finite element analysis. The results show that, within the evaluated design space, the proposed moon can increase the maximum achievable active volumetric torque density (VTD) by 7.6% to 8.6% for each of the considered gear ratios or it can reduce the no-load eccentric force of the maximum VTD moon-free 20:1 CyMG by as much as ∼86% without decreasing the VTD.

Parameter estimation and analysis of BLDC motor drive for electric vehicles application

This paper focuses on motor parameters of the Brushless DC motor. This main goal of this work is to demonstrate that BLDC motors are the best electric motor for electric vehicles. Due to their increased efficiency and reduced maintenance requirements, brushless DC motors are used. The paper proposes a framework to analyze Brushless DC motor characteristics using Code Composer Studio software and InstaSpin BLDC GUI. The framework's features, experimental results, and potential benefits are likely discussed in the paper. Simulink is used to resemble a BLDC motor with an ideal Back-Electro Motive Force (BEMF) voltage and its control drive. Experimental results have confirmed that the BLDC motor driving model predicts BLDC motor operation properly. Additionally, the BLDC motor parameter are estimated using Field-Oriented Control (FOC) mode. Both the simulation results and the hardware results have been presented.

Magnetic Field Energy Harvesting in Railway

Magnetic field energy harvesting (MFEH) is a method by which a system can harness an ambient, alternating magnetic field in order to scavenge energy. Presented in this article is a novel application of the concept aimed at the magnetic fields surrounding the rail current in electrified railway. Due to its noninvasive nature, the approach has the potential to be widely deployed as a part of low-cost trackside condition monitoring systems in order to increase lifetime and reduce maintenance requirements. In this article, the viability of MFEH in railway is substantiated experimentally—two different configurations are assessed both in a controlled laboratory environment as well as <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in situ</i> along Norwegian railway. When placed near an emulated section of railway carrying 200 A in the laboratory, the power output of the system is up to 40.5 mW at 50 Hz and 4.15 mW at 16 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\frac{2}{3}\; \mathrm{Hz}$</tex-math></inline-formula> . In the field, the prototype system harvests 109 mJ from a single freight train passing by, rendering an estimated daily energy output of 1.14 J in a moderately trafficked location. It is argued that the approach could indeed eliminate the need for battery replacements and potentially increase the lifetime of an energy-efficient, battery-powered condition monitoring system indefinitely.

A nanofiber based antiviral (TAF) prodrug delivery system

HIV and hepatitis B are two of the most prevalent viruses globally, and despite readily available preventive treatments unforgiving treatment regimens still exist, such as daily doses of medicine that are challenging to maintain especially in poorer countries. More advanced and longer-lasting delivery vehicles can potentially overcome this problem by reducing maintenance requirements and significantly increase access to medicine. Here, we designed a technology to control the delivery of an antiviral drug over a long timeframe via a nanofiber based delivery scaffold that is both easy to produce and use. An antiviral prodrug containing tenofovir alafenamide (TAF) was synthesized by initial conjugation to glycerol monomethacrylate followed by polymerization to form a diblock copolymer (pTAF) using reversible addition-fragmentation chain transfer (RAFT). In order to generate an efficient drug delivery system this copolymer was fabricated into an electrospun nanofiber (ESF) scaffold using blend electrospinning with poly(caprolactone) (PCL) as the carrier polymer. SEM images revealed that the pTAF-PCL ESFs were uniform with an average diameter of (787 ± 0.212 nm), while XPS analysis demonstrated that the pTAF was overrepresented at the surface of the ESFs. Additionally, the pTAF exhibited a sustained release profile over a 2 month period in human serum (HS), suggesting that these types of copolymer-based drugamers can be used in conjunction with electrospinning to produce long-lasting drug delivery systems.

Techno-Economic Assessment of an Air-Multiple PCM Active Storage Unit for Free Cooling Application

A latent energy storage (LES) unit is presented in this paper for free space cooling and ventilation application. The unit includes multiple phase change materials (PCM) to advance the thermal performance of common LES units. It is composed by metallic rectangular panels containing commercial paraffins with melting temperatures ranging among 20 °C and 25 °C and surrounded by air channels. The average cooling load of the unit corresponds to approximately 1 kW over 8 h. It fulfils the peak ventilation cooling load during summer of an office building in Portugal. The study provides a techno-economic analysis and the environmental benefits of the LES technology compared to a traditional air conditioning (AC) unit for the cooling and ventilation of an office building. During daytime, the air-multiple PCM unit allows reducing the energy consumption by nearly 200 kWh. The full charging of the PMs during nighttime, requires significant energy consumption due to the high air flowrate demand for full solidification. The competitiveness of such units can be achieved by introducing fins into the panels, allowing double the energy savings. In an overall perspective, the unit presents several benefits such as lower initial cost and reduced maintenance requirements (non-use of refrigerants and batteries) that also allows better personal health issues when related to traditional ACs.