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  • 1
    In: Energies, MDPI AG, Vol. 14, No. 20 ( 2021-10-14), p. 6663-
    Abstract: In this paper, a twelve-band hysteresis control is applied to a recent thirteen-level asymmetrical inverter topology by employing a robust proportional-integral (PI) controller whose parameters are decided online by genetic algorithm (GA). The asymmetrical inverter topology can generate thirteen levels of output voltage incorporating only ten switches and exhibits boosting capability. A 12-band hysteresis current control strategy is applied to ensure the satisfactory operation of the inverter. It is designed to provide a sinusoidal line current at the unity power factor. The tuning of the PI controller is achieved by a nature inspired GA. Comparative analysis of the results obtained after application of the GA and the conventional Ziegler–Nichols method is also performed. The efficacy of the proposed control on WE topology is substantiated in the MATLAB Simulink environment and was further validated through experimental/real-time implementation using DSC TMS320F28379D and Typhoon HIL real-time emulator (Typhoon-HIL-402).
    Type of Medium: Online Resource
    ISSN: 1996-1073
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2437446-5
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  • 2
    In: Buildings, MDPI AG, Vol. 12, No. 7 ( 2022-07-13), p. 1004-
    Abstract: Construction is a resource-intensive industry where a circular economy (CE) is essential to minimize global impacts and conserve natural resources. A CE achieves long-term sustainability by enabling materials to circulate along the critical supply chains. Accordingly, recent research has proposed a paradigm shift towards CE-based sustainability. However, uncertainties caused by fluctuating raw material prices, scarce materials, increasing demand, consumers’ expectations, lack of proper waste infrastructure, and the use of wrong recycling technologies all lead to complexities in the construction industry (CI). This research paper aims to determine the enablers of a CE for sustainable development in the CI. The system dynamics (SD) approach is utilized for modeling and simulation purposes to address the associated process complexity. First, using content analysis of pertinent literature, ten enablers of a CE for sustainable development in CI were identified. Then, causality among these enablers was identified via interviews and questionnaire surveys, leading to the development of the causal loop diagram (CLD) using systems thinking. The CLD for the 10 shortlisted enablers shows five reinforcing loops and one balancing loop. Furthermore, the CLD was used to develop an SD model with two stocks: “Organizational Incentive Schemes” and “Policy Support.” An additional stock (“Sustainable Development”) was created to determine the combined effect of all stocks. The model was simulated for five years. The findings show that policy support and organizational incentive schemes, among other enablers, are critical in implementing a CE for sustainable development in CI. The outcomes of this study can help CI practitioners to implement a CE in a way that drives innovation, boosts economic growth, and improves competitiveness.
    Type of Medium: Online Resource
    ISSN: 2075-5309
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2661539-3
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  • 3
    In: Frontiers in Energy Research, Frontiers Media SA, Vol. 10 ( 2022-11-14)
    Abstract: The globally soaring energy prices and electricity shortfall are major hurdles in the economic development of Pakistan. To cope with periodic power outages, small and medium enterprise (SME) business owners have to fall back on alternate power sources such as backup generators and uninterruptible power supplies (UPS), which further increase the per kWh cost of electricity, power quality issues, and greenhouse gas (GHG) emissions. On the contrary, grid-tied solar photovoltaic (PV) systems are not only economical and sustainable but support the national power grid to mitigate environmental emissions. This study aims to investigate and compare the techno-economic viability of grid-connected solar photovoltaic power plants for the manufacturing SME sector in four different districts of Punjab, Pakistan. Based on the technical, financial, and environmental indicators, a detailed techno-economic, sensitivity, and GHG emission analysis is conducted using RETScreen Expert software. The research findings clearly show that the proposed solar PV projects for all four locations are technically, financially, and environmentally viable, however, Sargodha as compared to other sites is the most feasible location with the highest capacity factor of 17.8 %, highest internal rate of return 14.9 %, lowest payback period 7.7 years, and least levelized cost of electricity 8.5 ¢/kWh. For validation, the simulation results are compared with performance metrics from PV plants erected in various parts of the world. Applying the same research approach to the whole industrial sector of Punjab recommends adding 13,469 MW of PV capacity to satisfy the industry’s 20446.21 GWh annual energy consumption and to cut emissions by 90,17,581 t C O 2 per year. This research work presents guidelines for researchers to evaluate the feasibility of suitable PV technologies for the SME sector thereby helping investors to have a holistic view of potential investment zones.
    Type of Medium: Online Resource
    ISSN: 2296-598X
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2022
    detail.hit.zdb_id: 2733788-1
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  • 4
    In: Materials, MDPI AG, Vol. 15, No. 24 ( 2022-12-14), p. 8944-
    Abstract: Pavement design is a long-term structural analysis that is required to distribute traffic loads throughout all road levels. To construct roads for rising traffic volumes while preserving natural resources and materials, a better knowledge of road paving materials is required. The current study focused on the prediction of Marshall stability of asphalt mixes constituted of glass, carbon, and glass-carbon combination fibers to exploit the best potential of the hybrid asphalt mix by applying five machine learning models, i.e., artificial neural networks, Gaussian processes, M5P, random tree, and multiple linear regression model and further determined the optimum model suitable for prediction of the Marshall stability in hybrid asphalt mixes. It was equally important to determine the suitability of each mix for flexible pavements. Five types of asphalt mixes, i.e., glass fiber asphalt mix, carbon fiber asphalt mix, and three modified asphalt mixes of glass-carbon fiber combination in the proportions of 75:25, 50:50, and 25:75 were utilized in the investigation. To measure the efficiency of the applied models, five statistical indices, i.e., coefficient of correlation, mean absolute error, root mean square error, relative absolute error, and root relative squared error were used in machine learning models. The results indicated that the artificial neural network outperformed other models in predicting the Marshall stability of modified asphalt mix with a higher value of the coefficient of correlation (0.8392), R2 (0.7042), a lower mean absolute error value (1.4996), and root mean square error value (1.8315) in the testing stage with small error band and provided the best optimal fit. Results of the feature importance analysis showed that the first five input variables, i.e., carbon fiber diameter, bitumen content, hybrid asphalt mix of glass-carbon fiber at 75:25 percent, carbon fiber content, and hybrid asphalt mix of glass-carbon fiber at 50:50 percent, are highly sensitive parameters which influence the Marshall strength of the modified asphalt mixes to a greater extent.
    Type of Medium: Online Resource
    ISSN: 1996-1944
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2487261-1
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  • 5
    Online Resource
    Online Resource
    IOP Publishing ; 2021
    In:  Materials Research Express Vol. 8, No. 8 ( 2021-08-01), p. 085303-
    In: Materials Research Express, IOP Publishing, Vol. 8, No. 8 ( 2021-08-01), p. 085303-
    Abstract: Epoxy and its composites have shown remarkable properties to be used for outdoor high voltage insulation applications. However, outdoor environment that contains UV-A radiations deteriorates the organic structure of epoxy-based insulators. To analyze the surface degradation and chemical changes in structure due to UV radiations, neat epoxy (NEPOX), 15 wt.% epoxy microcomposite (EMC 15) and 5 wt.% epoxy nanocomposite (ENC 5) were prepared and subjected to a specially fabricated UV chamber under accelerated conditions. The samples were analyzed with visual inspection, STRI hydrophobicity classification, and Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopy. The analyses confirmed the pattern of gradual degradation of surface structure due to the appearance of ester and carbonyl groups due to oxidation of hydrocarbon chains. FTIR peaks of C=O stretching at ∼1725.52 increased by 157.44%, 75.86% and 33.33% for NEPOX, EMC 15 and ENC, respectively. This shows that ENC-5 expressed better resistance against surface oxidation as compared to EMC 15 and NEPOX. Addition of fillers enhanced the chain intactness and nano filler performed even better due to greater surface area and surface energy.
    Type of Medium: Online Resource
    ISSN: 2053-1591
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2021
    detail.hit.zdb_id: 2760382-9
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  • 6
    In: Processes, MDPI AG, Vol. 10, No. 12 ( 2022-12-19), p. 2745-
    Abstract: The study’s goal is to assess the flexural strength of concrete that includes waste marble powder using machine learning methods, i.e., ANFIS, Support vector machines, and Gaussian processes approaches. Flexural strength has also been studied by using the most reliable approach of sensitivity analysis in order to determine the influential independent variable to predict the dependent variable. The entire dataset consists of 202 observations, of which 120 were experimental and 82 were readings from previous research projects. The dataset was then arbitrarily split into two subsets, referred to as the training dataset and the testing dataset, each of which contained a weighted percentage of the total observations (70–30). Output was concrete mix flexural strength, whereas inputs comprised cement, fine and coarse aggregates, water, waste marble powder, and curing days. Using statistical criteria, an evaluation of the efficacy of the approaches was carried out. In comparison to other algorithms, the results demonstrate that the Gaussian process technique has a lower error bandwidth, which contributes to its superior performance. The Gaussian process is capable of producing more accurate predictions of the results of an experiment due to the fact that it has a higher coefficient of correlation (0.7476), a lower mean absolute error value (1.0884), and a smaller root mean square error value (1.5621). The number of curing days was identified as a significant predictor, in addition to a number of other factors, by sensitivity analysis.
    Type of Medium: Online Resource
    ISSN: 2227-9717
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2720994-5
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  • 7
    In: Mathematics, MDPI AG, Vol. 10, No. 15 ( 2022-08-03), p. 2756-
    Abstract: Many authors have recently examined the relationship between symmetry and generalized convexity. Generalized convexity and symmetry have become a new area of study in the field of inequalities as a result of this close relationship. In this article, we introduce the idea of preinvex fuzzy-interval-valued functions (preinvex F∙I-V∙F) on coordinates in a rectangle drawn on a plane and show that these functions have Hermite–Hadamard-type inclusions. We also develop Hermite–Hadamard-type inclusions for the combination of two coordinated preinvex functions with interval values. The weighted Hermite–Hadamard-type inclusions for products of coordinated convex interval-valued functions discussed in a recent publication by Khan et al. in 2022 served as the inspiration for our conclusions. Our proven results expand and generalize several previous findings made in the body of literature. Additionally, we offer appropriate examples to corroborate our theoretical main findings.
    Type of Medium: Online Resource
    ISSN: 2227-7390
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2704244-3
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  • 8
    In: Processes, MDPI AG, Vol. 9, No. 8 ( 2021-07-24), p. 1277-
    Abstract: The authors of the present paper sought to conduct a numerical study on the convection heat transfer, along with the radiation and entropy generation (EGE) of a nanofluids (NFs) in a two and three-dimensional square enclosure, by using the FVM. The enclosure contained a high-temperature blade in the form of a vertical elliptical quadrant in the lower corner of the enclosure. The right edge of the enclosure was kept at low temperature, while the other edges were insulated. The enclosure was subjected to a magnetic field (MGF) and could be adjusted to different angles. In this research, two laboratory relationships dependent on temperature and volume fraction were used to simulate thermal conductivity and viscosity. The variables of this problem were Ra, Ha, RAP, nanoparticle (NP) volume fraction, blade aspect ratio, enclosure angles, and MGF. Evaluating the effects of these variables on heat transfer rate (HTR), EGE, and Be revealed that increasing the Ra and reducing the Ha could increase the HTR and EGE. On the other hand, adding radiation HTR to the enclosure increased the overall HTR. Moreover, an augmentation of the volume fraction of magnesium oxide NPs led to an increased amount of HTR and EGE. Furthermore, any changes to the MGF and the enclosure angle imposed various effects on the HTR. The results indicated that an augmentation of the size of the blade increased and then decreased the HTR and the generated entropy. Finally, increasing the blade always increased the Be.
    Type of Medium: Online Resource
    ISSN: 2227-9717
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2720994-5
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  • 9
    Online Resource
    Online Resource
    Institute of Electrical and Electronics Engineers (IEEE) ; 2020
    In:  IEEE Access Vol. 8 ( 2020), p. 28880-28887
    In: IEEE Access, Institute of Electrical and Electronics Engineers (IEEE), Vol. 8 ( 2020), p. 28880-28887
    Type of Medium: Online Resource
    ISSN: 2169-3536
    Language: Unknown
    Publisher: Institute of Electrical and Electronics Engineers (IEEE)
    Publication Date: 2020
    detail.hit.zdb_id: 2687964-5
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  • 10
    In: Electronics, MDPI AG, Vol. 12, No. 2 ( 2023-01-09), p. 341-
    Abstract: The source of energy extracted in renewable form has turned out to be a primary mainstream energy source, especially in the telecom sectors. Rapid growth of renewable sources has led to telecom operators concentrating more on designing the system with appropriate energy storage elements, providing control facilities, improving system efficiency and verifying uninterrupted power supplies. Therefore, this paper gives a novel approach of utilizing embedded control in energy generation consisting of a solar-wind hybrid energy system placed in isolated areas. For the purpose of integration of wind, together with the solar energy sources, into an increasingly efficient system, a single Cuk-Luo integrated DC-DC converter has been put forward. The proposed system has been modeled using MATLAB/Simulink and verified under various combinations of solar-wind energy sources without compromising the required power. In order to verify the proposed Cuk-Luo integrated converter with the energy management controller system, a prototype hardware is implemented and tested.
    Type of Medium: Online Resource
    ISSN: 2079-9292
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2662127-7
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