Cycle Operation Research Articles

Design and analysis of soft-switching isolated step-up/down DC–DC converter for fuel cell vehicles and EV battery charging applications

ABSTRACT With the increasing adoption of non-conventional energy sources, there is a significant demand for DC energy conversion systems as they play a crucial role in integrating power sources and loads that operate at different voltage levels. In this paper, a novel DC–DC converter topology is presented, which can efficiently perform Buck-boost operation with minimal duty cycle operation, making it an attractive option for DC energy conversion applications. Furthermore, its switching voltage stress is less than the voltage present at the output, allowing the use of low power rated devices. Additionally, the topology contains isolation between the load and source, which prevents circulating currents and protects the source from load harmonics. The proposed converter has the ability to achieve soft switching without using any extra circuitry. Moreover, the presented converter is evaluated against recently developed topologies in terms of active/passive components, gain, efficiency, and switching stress. Closed-loop analysis is done for the proposed converter using small-signal modeling. The converter is tested by subjecting it to a sudden step change at the input voltage from 20 V to 40 V in boost condition while maintaining a constant output voltage of 240 V. Additionally, load disturbances are introduced to assess the system’s robustness in closed-loop operation. In the laboratory, A 100-W prototype of the presented converter is built, which gives an efficiency of 95% at the rated load condition.

Development and characterization of tobacco suspension cell chassis NBS-1

Plant synthetic biology has significant theoretical advantages in exploration and production of plant natural products. However, its contribution to the field of biosynthesis is currently limited due to the lack of efficient chassis systems and related enabling technologies. Synthetic biologists often avoid tobacco as a chassis system because of its long operation cycle, difficulties in genetic and metabolic modification, complex metabolism and purification background, nicotine toxicity, and challenges in accurately controlling for agricultural production. Nevertheless, the tobacco suspension cell chassis system offers a viable solution to these challenges. The objective of this research was to develop a tobacco suspension cell chassis with high scientific and industrial potential. This chassis should exhibit rapid growth, high biomass, excellent dispersion, high transformation efficiency, and minimal nicotine content. Nicotiana benthamiana, which has high applicability in molecular technology, was used to induce suspension cells. The induced suspension cells, named NBS-1, exhibited rapid growth, excellent dispersion, and high biomass, reaching a maximum biomass of 476.39 g/L (fresh weight), which was significantly higher than that of BY-2. The transformation efficiency of the widely utilized pEAQ-HT transient expression system in NBS-1 reached 81%, which was substantially elevated compared to BY-2. The metabolic characteristics and bias of BY-2 and NBS-1 were analyzed using transcriptome data. It was found that the gene expression of pathways related to biosynthesis of flavonoids and their derivatives in NBS-1 was significantly higher, while the pathways related to alkaloid biosynthesis were significantly lower compared to BY-2. These findings were further validated by the total content of flavonoid and alkaloid. In summary, our research demonstrates NBS-1 possesses minimal nicotine content and provides valuable guidance for selecting appropriate chassis for specific products. In conclusion, this study developed NBS-1, a tobacco suspension cell chassis with excellent growth and transformation, high flavonoid content and minimal nicotine content, which has important guiding significance for the development of tobacco suspension cell chassis.

Mixed-fleet operation of battery electric bus and hydrogen bus: Considering limited depot size with flexible refueling processes

Electrified transit is crucial for promoting zero-emission transportation in metropolitan cities. However, this initiative faces considerable challenges in Hong Kong due to limited space available for parking and refueling bus fleets. Despite the inexpensive operational costs of battery electric buses (BEBs), plenty of space is required to park and refuel BEBs. Hydrogen buses (HBs) can partially address the space issue with a longer driving range and shorter refueling time compared to the BEBs, whereas more operational costs must be spent. Therefore, a mixed fleet with BEB of HB tends to be a more cost-effective solution. In consideration of the distinctive characteristics of BEBs and HBs, this study develops an integrated vehicle scheduling and refueling of mixed fleets with multiple depots (IVSR-MFMD) restricted by the limited depot size (i.e., space provided for bus parking and bus refueling), where flexible refueling processes, allowing for uncertain refueling start times and refueling amounts, are endogenously incorporated into the operational cycle. The speed-up techniques are further used to reduce problem dimensions and reformulate the model. A two-route-two-depot example and a real-world case in Hong Kong are used to verify the model. The results demonstrate that adopting HB can efficiently reduce depot size and achieve lower operational costs when routes consume massive energy. Additionally, it is found that flexible refueling processes lead to lower operational costs, and the customized speed-up techniques can significantly improve computational efficiency.

Bioelectricity production and bioremediation potential of Withania somnifera in plant microbial fuel cells

In p-MFCs living plants photosynthesize within a bio-electrochemical circuit. The plant exudes organic waste material from the roots. In the rhizosphere, bacteria consume these wastes by oxidizing them in contrast to the atmosphere that reduces it. This redox reaction along with photosynthesis can be harnessed as bioelectricity. In this work, the plant Withania somnifera (L.) Dunal was used for generating bioelectricity from the root exudates and organic matter available in the soil. An open circuit voltage of 930±21 mV was achieved between multiple cycles of operation. The cell voltage further increased to 1260±140 mV with enrichment in the form of discards from vegetable matter. The peak recorded voltage was 1400 mV. Graphite fibre felt electrodes ensured uniform microbial growth with power densities that were achieved at 57 mW/m2 and 84 mW/m2 with and without enrichment respectively. ATR-FTIR demonstrated complete degradation of specific compounds attached to the carbon matrix in the soil along with the polysaccharide content from the enrichments. Additionally, this work also monitored the changes in soil pH and its homogeneity, the impact of photosynthetically active radiation, humidity, and the presence of CO2 in the air, and how it affects plant growth and ultimately the microbes at the rhizosphere which accounted for the bioremediation and the resultant bioelectricity production. SEM imaging provided additional evidence that the presence of electrochemically active soil bacteria, an anaerobic environment, and electrode characteristics are crucial for the development of conductive biofilms.

An experimental study on the defrosting performances of an ASHP having a novel dual-fan outdoor coil under different levels of frosting evenness along airflow direction

Uneven frosting along the airflow direction is a common phenomenon that can accelerate deteriorating the heating efficiency of ASHP units under frosting conditions. To effectively alleviate this uneven frosting phenomenon, an experimental ASHP unit having a novel dual-fan outdoor coil (ASHP / DFOC) was developed in a previous experimental study. The ability of the DFOC on achieving even frosting along the airflow direction, and the operating performances of the experimental ASHP/DFOC unit at different levels of even frosting evenness were experimentally and numerically investigated. However, the defrosting performances of the experimental ASHP/DFOC unit at different levels of frosting evenness remain to be evaluated, which was nonetheless essential for developing an on-demand defrosting initiation method for achieving higher defrosting efficiency. Therefore, the defrosting performances of the experimental ASHP/DFOC unit at different levels of even frosting were experimentally investigated in this paper. Five experimental cases with different levels of even frosting were designated, and the defrosting performances of the experimental ASHP/DFOC unit, including the defrosting time duration at different defrosting stages and the energy consumption during defrosting, were analyzed in great detail. The results demonstrated that during a single frosting-defrosting operating cycle, the defrosting always proceeded from one side to the other along the refrigerant flow direction. The evener the frosting level, the longer the frosting and defrosting duration, and the lower the defrosting efficiency. However, during multiple frosting-defrosting cycles, the evener the frosting level, the higher the comprehensive heating performances of the experimental ASHP/DFOC unit. The results from this study have provided a valuable basis for developing a more accurate defrosting initiation method with a higher defrosting efficiency for ASHP/DFOC units.

Feasibility of sustainable reusability of Ni/char catalyst for synthetic gas production via catalytic steam gasification

Ni/char catalyst is one of the most promising catalysts for enhancing gas production, particularly syngas from catalytic steam gasification of biomass. In the current study, one unmodified (Ni/MMchar) and two modified catalysts (Ni/NaMMchar and Ni/NaAceMMchar) were utilized to investigate the reusability potential of Ni/char catalyst for catalytic steam gasification of bamboo in a two-stage fixed-bed reactor including the changes in catalyst characteristics. N2 adsorption-desorption by BET, scanning electron microscope connected with energy-dispersive X-ray spectrometer (SEM-EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses were utilized for examining their characteristics. The findings indicated that the three catalysts could maintain the reusability potential in catalytic steam gasification of bamboo for twice cycles. The syngas reduction percentages in the second cycles of the catalysts ranged between 11.0 and 22.8 %. H2/CO ratios of all spent catalysts lined in the range of 4.10 − 2.45. The low heating values of syngas products were in the range of 8.83–8.19 MJ/Nm3. Considering the catalyst characteristics, the increasing cycles of catalyst operations induced carbon deposition, resulting in the reduction of specific surface areas. SEM-EDS images of the used catalysts appeared the coke layer and the Ni metal sintering on the surfaces. The uses of catalysts encouraged the transformation of Ni metal active site into NiO, Ni2O3 and Ni3C forms. These phenomena were the major causes of catalyst deactivation. The changes in the characteristics and catalyst activity controlled the gasification reactions, resulting in the catalyst deactivation and gaseous products.

Effect of pillar width on the stability of the salt cavern field for energy storage

Abstract Effective planning of the cavern field involves determining the optimal pillar width between the caverns and the feasible number of caverns based on geological and mining conditions. The proper design of the pillar width is crucial to ensure the stability of the cavern field and the rational utilization of the rock salt deposit. The stability of the pillars is a complex problem influenced by various factors, including rock salt creep, changes in the cavern pressure during operational cycles, mechanical parameters, and failure criteria of the rock salt. To address this problem, the stability of the cavern field in relation to the number of caverns and pillar widths is evaluated. The evaluation is based on the following criteria: displacements, von Mises stress, strength/stress ratio, and safety factor. Three variations of pillar width and three variants of cavern fields, differing in the number of caverns, are considered. Results show that the allowable pillar width is affected by the number of caverns in the cavern field. Moreover, the stability analysis reveals uneven stress and deformation distribution in the cavern field. When the pillar width is 2.0–3.0 times the diameter of a cavern, pillars at the centre exhibit poorer stability than those at the edges of the cavern field. However, with a narrower pillar width, the highest displacements occur at the field's edges. The findings of this study provide a valuable date in the planning, design, and operation of new cavern fields for the underground storage of energy sources such as oil, natural gas, hydrogen, and compressed air in rock salt deposits.

Evaluation of comprehensive early warning for higher education institutions' cloud model of simulated enterprise management cockpit.

The cross-disciplinary virtually simulated platform for enterprise management in universities' new business courses is an initiative practical framework based on scenario-driven tasks. However, there is a prominent conflict between the rapid operating cycle of simulation enterprises plus their fierce competitions and the strategic demand for real-time analysis for operational data. Based on such demand, this study takes the development method of the simulated enterprise management cockpit from Guangzhou Huashang College as an example. It adopts the combined weighting method based on cloud models to determine indicator weights, then qualitative and quantitative data analyses are conducted from five aspects: "business, finance and operation", "customer management and marketing", "internal operational objectives", "product development strategy", along with "team building and management". This approach achieves a comprehensive evaluation and early warning of the enterprise management process. Specifically, the subjective weights are determined by the Analytic Hierarchy Process, while the objective weights by the entropy weight method, finally verified by cloud model evaluation of its overall indicator performance. The design can evaluate the comprehensive performance of enterprise management indicators and students' activity participation through the cloud-based application and the digital cockpit, so as to fully presents the enterprise's overall management level, along with judgement of whether it is reasonable through pointers in different colors. In addition, apparent indicator-related characteristics are also utilized to assess future decision-making directions. Finally, this comprehensive approach can timely optimize operation strategies and facilitate budget allocation for future development.

First development of transparent wood-based triboelectric nanogenerator (TW-TENG): Cooperative incorporation of transparency, aesthetic of wood, and superior triboelectric properties

The combination of triboelectric nanogenerator (TENG) and wood-based materials offers a sustainable strategy for energy harvesting. The main challenge in realizing wood-based TENG is to increase the polarizabilities of wood. Herein, we introduce the first instance of a transparent wood-based triboelectric nanogenerator (TW-TENG), which synergistically incorporates superior triboelectric properties, optical properties, and aesthetic of wood. Addressing the challenges of weak polarizability and opacity inherent in natural wood, we propose a functionalized modification approach involving delignification and impregnation with UV-curable resin. In this study, leveraging delignification and the strong electron-donating groups within the UV-curable resin, the electrical output performance of TW-TENG is improved by 6.5 times compared to that of natural wood, and maintains stability over 10,000 operational cycles. Moreover, the matching refractive index between the UV-curable resin and the wood substrate offers TW-TENG with high transparency, achieving an optical transmittance of up to 88.8 %, exhibiting the unique aesthetic value of transparent wood. Furthermore, we demonstrate the potential applications of TW-TENG in energy harvesting, sensor technologies, smart decorative materials, smart home systems, and beyond, exemplified through its utilization in electrical output generation by pressing, capacitor charging and discharging, and self-powered multiplexed sensing smart target shooter.

Thermodynamic analysis of an enhanced ejector vapor injection refrigeration cycle for CO2 transcritical operation at low evaporating temperatures

The main drawback associated with CO2 refrigeration systems is related to their performance reduction during transcritical operation at warm climate conditions, which may be compensated by better cycle architectures such as the split-cycle with subcooling or the flash-tank configuration, among others. Specifically, the use of standard gas-ejectors together with parallel compressors provides even better efficiency improvements, not being able to use them with low-temperature evaporators to prevent the triple point inside the ejector. This paper proposes an enhanced cycle with a gas ejector for two-stage compressor architectures with vapor injection from the flash-tank, which is able to operate at low evaporating temperatures and that provides a greater performance improvement the more severe the climate conditions are. The methodology conducted is based on a thermodynamic analysis that includes parametric evaluation and cycle optimization, comparing the results to a conventional CO2 transcritical cycle with flash-tank and dynamic vapor injection architecture. The main results show that a maximum Coefficient of Performance improvement of 17.5% is achievable for transcritical operation at -40 °C evaporating temperature. The compressor displacement capacity required with the enhanced cycle is up to 9% lower for the same refrigeration demand, reducing the electrical consumption as well as the compressor expenditure. Moreover, greater vapor injection mass flow rates are obtained by the gas-ejector injection with discharge temperature reductions up to 18%, enhancing the system reliability.

Coupling life cycle audition and operation research methods to achieve sustainable rapeseed production system

Coupling life cycle audition and operation research methods to achieve sustainable rapeseed production system

Enhanced electrochemical performance of MgFeO4 spinel as anode materials for Lithium-ion batteries through manganese doping

Existing graphite anode materials are reaching their limits, and iron-based AB2O4 spinel materials are considered as potential anodes for Li-ion batteries owing to their significant theoretical capacities. In this work, novel nanocrystalline MgFe2-xMnxO4 (x = 0, 0.1, 0.2, and 0.3) spinel ferrites were evaluated as anode materials for high-capacity Li-ion batteries. The Mn-doped MgFe2-xMnxO4 (x = 0, 0.1, 0.2, and 0.3) spinel ferrites were synthesized through a facile sol-gel synthesis method coupled with an annealing process. Their crystal structure, morphology, and purity were examined via X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). The X-ray diffraction analyses with Rietveld refinement of the synthesized ferrites reveal pure cubic structure with a characteristic Fd3̅m space group for all prepared samples. This was confirmed by Raman spectroscopy by revealing five spinel Raman active modes. The SEM images showed interconnected nanosized particles for all compositions, which led to a porous morphology. Their electrochemical proprieties as anode materials for Li-ion batteries were examined by cyclic voltammetry and galvanostatic charge-discharge tests. For all compositions, the cyclic voltammetry plots demonstrate the conversion type for the Li-ion storage mechanism. At an applied current density of 150 mA g−1, the compositions x = 0, 0.1, 0.2, and 0.3 show initial discharge/charge capacities of 1235/712, 1187/680, 1542/938, and 1239/768 mAh g−1, respectively. After 100 operational cycles, their galvanostatic charge/discharge capacities remain 529/534, 612/606, 642/663, and 700/700 mAh g−1. However, the compositions x = 0.2 and 0.3 exhibit excellent cycling stability during 100 cycles, even at higher rates. As a result, the Mn doping led to enhanced specific capacity and cycling stability of the MgFe2O4 spinel. The optimized compositions with x = 0.2 and 0.3 are, thus, proposed as promising anodes materials compositions for Li-ion batteries.

Numerical optimization study on the thermal management of planar sodium nickel chloride battery module

A numerical study is conducted to build up a thermal management strategy for a battery module consisting of stacked planar sodium metal chloride (Na-MCl2) unit cells at the intermediate temperature of 180 °C. Because the sodium metal chloride battery for an energy storage system operates for a long cycle period and maintains a high temperature, a different approach is required considering uniform temperature distribution and efficiency compared with lithium-ion battery. This study starts with a lumped analytical model for preliminary investigation and moves on to a computational fluid dynamics (CFD) analysis for a more sophisticated optimization. In this study, the 2 × 4 and 3 × 3 arrangements of cylinders, each of which represents a 10-cell stack, are considered. From the lumped model in the preliminary design, the insulation thickness and initial approach values of the detailed design are determined by predicting the temperature and heat generation throughout the entire operating cycle of the module. In the detailed CFD analysis, passive thermal management through natural convection has a limitation of cell temperature uniformity. To achieve a uniform cell temperature distribution, case studies are conducted with active fans inside the module. The optimal operating points are proposed based on the overlaid response surface. Finally, for the operating points in this study, the module efficiencies are compared considering the cell failure mode. The efficiencies of optimized module are increased to 26.9 % for 2 × 4 and 21.2 % for 3 × 3 arrangements.

Chip-Inspired Design of High-Performance Lithium-Sulfur Batteries by Integrating Monodisperse Sulfur Nanoreactors on Graphene.

For practical application of lithium-sulfur batteries (LSBs), designing devices with an overall optimal structure instead of modifying electrode materials is significant. Herein, we report a chip-inspired design of a vertically integrated structure as an LSB cathode by implanting Mo2C nanoparticles and nanosulfur into the reduced graphene oxide (rGO) matrix. This configuration enabled the synthesis of isolated sulfur nanoreactors (S-NRs) integrated in a tandem array on the rGO, generating chip-like integrated LSBs. The spatial confinement/protection and concentration gradient of the S-NRs effectively avoided the dissolution, diffusion, and loss of polysulfides, thereby enhancing the sulfur utilization and redox reaction kinetics. Additionally, the adaptive storage energy can be improved by utilizing the tandem, isolation, and synergistic multiplicative effect among the nanoreactor units. As a result, the integrated LSB cathode obtained excellent electrochemical performances with an initial capacity of 1392 mAh g-1 at 0.1C, a low capacity decay rate of 0.017% per cycle during 1500 cycles of operation at 0.5C, and a superior rate performance. This work provides a rational design idea and method of further advancing the precise preparation of high-performance energy storage devices.

Thermodynamic optimization of heat exchanger circuitry via genetic programming

In this study, an evolutionary thermodynamic technique was developed for the optimization of heat exchanger circuitry. The proposed technique is capable of handling the unrestrained implementation of genetic operators while ensuring circuitry feasibility and basic manufacturability. The optimization tool was used to clarify the optimal heat transfer features in relation to the characteristics of the refrigerant and to provide a thermodynamic interpretation of the optimization results to extract general design guidelines. Evaporator circuitry optimization was conducted under given cooling capacity, superheating degree, and boundary conditions representative of air-conditioning applications. The consistency between the minimum entropy generation and the maximum coefficient of performance (COP) was demonstrated under these settings. Accordingly, heat exchanger configurations that take maximum advantage of the thermodynamic benefits of each refrigerant are proposed by optimizing the distribution of friction and heat transfer irreversibility. Consequently, the evaporator outlet pressure increases, thus lowering the compression ratio and maximizing the COP. The developed optimization method maximizes the benefits of low-GWP alternative refrigerants and shows that zeotropic mixtures may exhibit performance analogous to that of R32 and higher than that of R410A by approaching a Lorenz cycle operation.

Equivalent consumption minimization strategy based on global optimization of equivalent factor for hybrid tractor

Due to the increase in emission requirements for non-road vehicles in many countries and the reduction of agricultural personnel, tractors are developing towards high horsepower and electrification. According to the working conditions of high-horsepower tractors, a hydromechanical continuously variable transmission (HMCVT) is designed for hybrid tractors. Taking a tractor equipped with this transmission as the research object, an equivalent factor global optimization model was established and a genetic algorithm was used to optimize the equivalent factor S offline to obtain the optimal equivalent factor of the tractor under different operating mileage and the initial state of charge (SOC) of battery. By using the optimized equivalent factor, the tractor can be in the charge depleting (CD) mode for a longer time on the premise of making full use of the energy in the battery, so as to improve the auxiliary ability of the motor in the whole operation cycle to reduce the fuel consumption of the tractor. The effectiveness of the control strategy is verified by MATLAB/Simulink and hardware in the loop (HIL) tests, and the fuel economy of tractors is improved by 2.939% and 3.909% respectively in the two tests.

Ga2O3/NiO junction barrier Schottky diodes with ultra-low barrier TiN contact

Power Schottky barrier diodes (SBDs) face an inherent trade-off between forward conduction loss and reverse blocking capability. This limitation becomes more severe for ultra-wide bandgap (UWBG) SBDs due to the large junction field. A high Schottky barrier is usually required to suppress the reverse leakage current at the price of an increased forward voltage drop (VF). This work demonstrates a Ga2O3 junction barrier Schottky (JBS) diode that employs the embedded p-type NiO grids to move the peak electric field away from the Schottky junction, thereby allowing for the use of an ultra-low barrier TiN Schottky contact. This JBS diode concurrently realizes a low VF of 0.91 V (at forward current of 100 A/cm2) and a high breakdown voltage over 1 kV, with the VF being the lowest in all the reported vertical UWBG power diodes. Based on the device characteristics measured up to 200 °C, we further analyze the power loss of this JBS diode across a wide range of operational duty cycles and temperatures, which is found to outperform the TiN/Ga2O3 SBDs or NiO/Ga2O3 PN diodes. These findings underscore the potential of low-barrier UWBG JBS diodes for high-frequency, high-temperature power electronics applications.

Application of Acoustic Emission Technology for Bearing Condition Monitoring on Passenger Ropeway

Rolling bearings are important stressed components of driving wheels and detour wheels on passenger ropeway, and their failure may lead to accidents and casualties. After the ropeway is installed and put into operation, the rolling bearings in the wheels are difficult to disassemble. Once disassembled, the bearing may be damaged. Due to the installation position and the complex operation environment, the health status of the rolling bearings is a blind spot for ropeway inspection and detection. Acoustic emission detection technology is used to monitor the rolling bearings of passenger ropeways. After a large number of field tests, the acoustic emission monitoring program and signal analysis method of rolling bearing on ropeway were proposed. The parameter characteristics of acoustic emission signals obtained in bearing operating were analyzed from two aspects: the ropeway operating cycle and the bearing operating cycle. Spectrum analysis of typical signals was performed, and the spectrum characteristics of typical acoustic emission signals of rolling bearing during the operation of the ropeway were obtained. On-site tests results show that using acoustic emission technology to perform condition monitoring and fault diagnosis of low-speed rolling bearings on passenger ropeways has good application prospects.

Efficient adsorptive removal of 2,4-dichlorophenoxyacetic acid (2,4-D) using biomass derived magnetic activated carbon nanocomposite in synthetic and simulated agricultural runoff water

This study focused on evaluating the efficacy of a magnetic activated carbon material (CPAC@Fe3O4) derived from pods of copper pod tree in adsorbing the toxic herbicide, 2,4- (2,4-D) from aqueous solutions. The synthesized CPAC@Fe3O4 adsorbent, underwent various characterization techniques. FESEM images indicated a rough surface, incorporating iron oxide nanoparticles, while EDS analysis confirmed the presence of elements like Fe, O, and C. Notably, the CPAC@Fe3O4 exhibited high surface area (749.10 m2/g) and pore volume (0.5351 cm³/g), confirming its mesoporous nature. XRD investigations identified distinct signals associated with graphitic carbon and magnetite nanoparticles, while VSM analysis verified its magnetic properties with a high magnetic saturation value (2.72 emu/g). The adsorption process was exothermic, with a decrease in adsorption capacity at higher temperatures. Freundlich isotherm provided the best fit for the adsorption, and the pseudo-second-order equation effectively described the kinetics. Remarkably, the maximum adsorption capacity ranged from 246.43 to 261.03 mg/g, surpassing previously reported values. The ΔH° value (−8.67 kJ/mol) suggested a physisorption mechanism, and the negative ΔG° values established the spontaneous nature. Furthermore, the synthesized adsorbent demonstrated exceptional reusability, allowing for up to five cycles of adsorption-desorption operations. When applied to simulated agricultural runoff, CPAC@Fe3O4 showcased a significant adsorption capacity of 160.71 mg/g for 50 mg/L 2,4-D, using a 0.2 g/L dosage at pH 2. This study showcased the transformation of copper pod biomass into a valuable magnetic nanoadsorbent capable of efficiently eliminating the noxious 2,4-D pollutant from aqueous environments.

Evaluating novel building products through a building design-oriented LCA approach: Example of VIPs in terrace applications

Abstract INTRODUCTION: The construction industry is considered conservative in adopting new products/technologies, and environmental characteristics are one of the most important features of novel solutions. In this context, our study aims to present a building design-oriented assessment of a novel building product by extending the functional unit scope and involving multiple realistic building design scenarios. The task will be performed using the example of vacuum insulation panels (VIPs), a superinsulation product that can be used in various building applications. The study will focus on terrace insulation applications, where VIPs are an attractive solution for building designers due to the possibility of barrier-free floor design. However, they lack environmental evaluation. METHOD: A life cycle assessment (LCA) analysis is performed on two hypothetical buildings located in Ljubljana (Slovenia) for the cradle-to-gate and operational energy life cycle stages (A1-A3 + B6 according to EN 15978). A whole-year dynamic thermal response simulation was executed using the Design Builder software. Five barrier-free terrace design scenarios that influence the embodied and operational carbon footprint (while maintaining the functional and architectural integrity of the building design) were examined. RESULTS: The study showed that although EPS insulation showed a smaller embodied carbon footprint on the product level, the building level analysis showed that using VIPs in terrace applications leads to favourable or comparable environmental impact. CONCLUSIONS: Building products can be evaluated on three functional unit levels: product, application and building. By extending the boundaries from the product/application level to the entire building level, the study provides an example of a building design-oriented approach to LCA. The complexity increases by upgrading the functional unit scope to the building level, while the results become more case-specific and less general. Ideally, a novel building product should show environmental superiority on all three levels. However, as there are almost countless design possibilities in buildings, environmental superiority (or inferiority) on the product level does not necessarily indicate superiority (or inferiority) on the building level.