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  • 1
    In: Sustainability, MDPI AG, Vol. 13, No. 12 ( 2021-06-21), p. 6950-
    Kurzfassung: In this research, we planned and conducted estimations for developing a pilot-scale Clean Development Mechanism (CDM) project for group plant activities in the Vietnam electricity/energy sector. The overall aim of this paper is to assess the power generation potential of rice husk power plants in the Mekong Delta. We intend to set up a rice husk energy balance flowchart for the whole Mekong River Delta in the year 2021 and suggest policies that can be used for the power generation of unused rice husk, to avoid having them pollute rivers and canals. We put forward a safe and environmentally friendly solution to thoroughly minimize the current serious pollution of rivers and canals in the Mekong River Delta caused by the increasing quantity of unused rice husk. The results of this paper are based on the estimation of electricity potential of a group of rice husk power development plants in the Mekong River Delta with a capacity of 11 MW per plant, including carbon dioxide emission reductions (CERs) and CER credits, along with estimations of their economic criteria (NPV, B/C, IRR), both W/CDM and W/O CDM.
    Materialart: Online-Ressource
    ISSN: 2071-1050
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2021
    ZDB Id: 2518383-7
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    In: Medicina, MDPI AG, Vol. 59, No. 5 ( 2023-04-29), p. 864-
    Kurzfassung: Background and Objectives: To describe the clinical and biological characteristics of patients with hypertriglyceridemia-induced acute pancreatitis (HTG-AP) and to evaluate the effectiveness of therapeutic plasma exchange (TPE) in the management of HTG-AP. Materials and Methods: A cross-sectional study was conducted on 81 HTG-AP patients (30 treated with TPE and 51 treated conventionally). The main outcome was a decrease in serum triglyceride levels ( 〈 11.3 mmol/L) within 48 h of hospitalization. Results: The mean age of participants was 45.3 ± 8.7 years, and 82.7% were male. Abdominal pain was the most frequent clinical sign (100%), followed by dyspepsia (87.7%), nausea or vomiting (72.8%), and a bloated stomach (61.7%). The HTG-AP patients treated with TPE had significantly lower calcemia and creatinemia levels but higher triglyceride levels than those who received conservative treatment. They also had more severe diseases than those treated conservatively. All patients in the TPE group were admitted to the ICU, whereas the ICU admission rate in the non-TPE group was 5.9%. The TPE patients were more likely to experience a rapid decrease in triglyceride levels within 48 h of treatment than those treated conventionally (73.3% vs. 49.0%, p = 0.03, respectively). The decrease in triglyceride levels did not depend on the age, gender, or comorbidities of the HTG-AP patients or the severity of disease. However, TPE and early treatment in the first 12 h of disease onset were effective in rapidly reducing serum triglyceride levels (adjusted OR = 3.00, p = 0.04 and aOR = 7.98, p = 0.02, respectively). Conclusions: This report demonstrates the effectiveness of early TPE in reducing triglyceride levels among HTG-AP patients. More randomized clinical trials studies with a large sample size and post-discharge follow-up are needed to confirm the effectiveness of TPE methods in managing HTG-AP.
    Materialart: Online-Ressource
    ISSN: 1648-9144
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2023
    ZDB Id: 2088820-X
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    In: Toxics, MDPI AG, Vol. 10, No. 6 ( 2022-06-10), p. 315-
    Kurzfassung: We investigated changes in some laboratory indices and the liver histology of chronic hepatitis patients who were exposed to dioxin. In 2014, we collected liver biopsy samples for histopathological examination from 33 chronic hepatitis patients living around the Da Nang Airbase, which is a dioxin-contaminated area due to the herbicide spraying in Vietnam. Dioxin exposure was measured by its levels in the blood. METAVIR classification was used to clarify the liver fibrosis stage. Laboratory tests included ten biochemical and six hematological indices that were measured in the blood. A regression linear model and binary logistic regression were used for data analysis. The observed alterations in the liver at the histological level mainly comprised hydropic degenerative hepatocytes, lymphocytes and polynuclear leukocytes surrounding the liver cells and granular and lipoic degeneration. In addition, increased TCDD levels were associated with increasing aminotransferase (AST), alanine aminotransferase, protein and total bilirubin levels and liver fibrosis stage. Similarly, increased TEQ-PCDD/Fs levels were associated with higher levels of AST and protein and liver fibrosis stage. In conclusion, dioxin exposure altered the liver histology and increased some biochemical marker indices and the liver fibrosis stage of chronic hepatitis patients living in dioxin-contaminated areas in Da Nang, Vietnam.
    Materialart: Online-Ressource
    ISSN: 2305-6304
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2022
    ZDB Id: 2733883-6
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    In: Water, MDPI AG, Vol. 15, No. 12 ( 2023-06-09), p. 2186-
    Kurzfassung: The pollution of synthetic dyes in wastewater exerts many negative impacts on the environment and human health. There is an increasing demand for the degradation of dyes, with an emphasis on photocatalysis. Here, we investigated the bio-mediated synthesis of ZnO using Chrysanthemum spp. flower extract and its utilization for the removal of methylene blue dye under sunlight irradiation. The bandgap energy of green ZnO nanoparticles was determined to be 3.0. The Taguchi L9 (34) orthogonal array design was applied to optimize the photocatalytic degradation of methylene blue dye by green ZnO particles. Four parameters, including the initial concentration (10–50 mg/L), ZnO dosage (0.33–1.0 mg), contact time (30–120 min), and pH (4–10) of the solution, were surveyed based on the Taguchi design. We found that the test result (99.0%) at 10 mg/L was almost equivalent to the predicted value (99.5%) of degradation efficiency. The reaction mechanisms shed light on the major role of reactive oxygen species (•O2−, •OH). More importantly, the green ZnO particles could be reused for at least five cycles and demonstrated high stability.
    Materialart: Online-Ressource
    ISSN: 2073-4441
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2023
    ZDB Id: 2521238-2
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    In: Sustainability, MDPI AG, Vol. 15, No. 12 ( 2023-06-15), p. 9603-
    Kurzfassung: This study examined the willingness-to-pay (WTP) of consumers and the determinants of eco-labeling for the organic cocoa powder produced in the Dong Nai UNESCO Biosphere Reserve (DNBR), Southern Vietnam. Eco-labels are designed according to the tiers of eco-labeling for biosphere reserves (BR) introduced by UNESCO; they include BR Destination (Tier 1), BR Quality (Tier 2), and Professional Certification (Tier 3) labels. Questionnaires were delivered to 203 customers in the DNBR and nearby places, such as Dong Nai and HCMC. This study employed a hybrid approach using descriptive statistics, an ANOVA test, and a Partial Least Squares Structural Equation Model (PLS-SEM). The results indicate that gender and educational level have a positive effect on consumers’ preferences. Customers are willing to pay more for cocoa powder with an eco-label than one with an organic label. Perceived food safety and product knowledge lower customers’ WTP, whereas agricultural environment and pricing concerns increase it. Tier 2 is suggested for labeling cocoa powder in the DNBR. The DNBR Management Board, together with the federal and provincial governments, should all follow a similar certification process. Increased eco-label awareness is crucial for the future of environmentally responsible shopping and responsible business practices.
    Materialart: Online-Ressource
    ISSN: 2071-1050
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2023
    ZDB Id: 2518383-7
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
    In: Drones, MDPI AG, Vol. 6, No. 12 ( 2022-12-12), p. 408-
    Kurzfassung: In this work, we design an intelligent reflecting surface (IRS)-assisted Internet of Things (IoT) by enabling non-orthogonal multiple access (NOMA) and unmanned aerial vehicles (UAV) approaches. We pay attention to studying the achievable rates for the ground users. A practical system model takes into account the presence of hardware impairment when Rayleigh and Rician channels are adopted for the IRS–NOMA–UAV system. Our main findings are presented to showcase the exact expressions for achievable rates, and then we derive their simple approximations for a more insightful performance evaluation. The validity of these approximations is demonstrated using extensive Monte Carlo simulations. We confirm the achievable rate improvement decided by main parameters such as the average signal to noise ratio at source, the position of IRS with respect to the source and destination and the number of IRS elements. As a suggestion for the deployment of a low-cost IoT system, the double-IRS model is a reliable approach to realizing the system as long as the hardware impairment level is controlled. The results show that the proposed scheme can greatly improve achievable rates, obtain optimal performance at one of two devices and exhibit a small performance gap compared with the other benchmark scheme.
    Materialart: Online-Ressource
    ISSN: 2504-446X
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2022
    ZDB Id: 2934569-8
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
    In: Sensors, MDPI AG, Vol. 19, No. 11 ( 2019-05-30), p. 2475-
    Kurzfassung: In this paper, we investigate power domain division-based multiple access (PDMA) to support the base stations (BS) equipped with multiple antennas to serve mobile users. Such a system deploys multiple input single output (MISO)-based wireless transmission and a full-duplex (FD) scheme. Furthermore, such MISO PDMA system consists of BS employing transmit antenna selection to reduce complexity in signal processing at the receivers. We distinguish two kinds of mobile users, device-to-device (D2D) users and traditional users. In such MISO PDMA, there exists a trade-off between outage performance of each PDMA user and power allocation factors. Since the implementation of the FD scheme at PDMA users, bandwidth efficiency will be enhanced despite the existence of self-interference related to such FD. In particular, exact expressions of outage probability are derived to exhibit system performance with respect to D2D users. Finally, valuable results from the simulated parameters together with the analytical results show that MISO PDMA can improve its performance by increasing the number of transmit antennas at the BS.
    Materialart: Online-Ressource
    ISSN: 1424-8220
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2019
    ZDB Id: 2052857-7
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 8
    In: Sensors, MDPI AG, Vol. 22, No. 17 ( 2022-08-31), p. 6576-
    Kurzfassung: The evolution of Internet of Things (IoT) networks has been studied owing to the associated benefits in useful applications. Although the evolution is highly helpful, the increasing day-to-day demands of mobile users have led to immense requirements for further performance improvements such as efficient spectrum utilization, massive device connectivity, and high data rates. Fortunately, reconfigurable intelligent surfaces (RIS) and non-orthogonal multiple access (NOMA) techniques have recently been introduced as two possible current-generation emerging technologies with immense potential of addressing the above-mentioned issues. In this paper, we propose the integration of RIS to the existing techniques (i.e., NOMA and relaying) to further enhance the performance for mobile users. We focus on a performance analysis of two-user group by exploiting two main performance metrics including outage probability and ergodic capacity. We provide closed-form expressions for both performance metrics to highlight how NOMA-aided RIS systems provide more benefits compared with the benchmark based on traditional orthogonal multiple access (OMA). Monte-Carlo simulations are performed to validate the correctness of obtained expressions. The simulations show that power allocation factors assigned to two users play a major role in the formation of a performance gap among two users rather than the setting of RIS. In particular, the strong user achieves optimal outage behavior when it is allocated 35% transmit power.
    Materialart: Online-Ressource
    ISSN: 1424-8220
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2022
    ZDB Id: 2052857-7
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 9
    Online-Ressource
    Online-Ressource
    MDPI AG ; 2019
    In:  Sensors Vol. 19, No. 22 ( 2019-11-06), p. 4840-
    In: Sensors, MDPI AG, Vol. 19, No. 22 ( 2019-11-06), p. 4840-
    Kurzfassung: In this paper, we investigate the outage performance in secondary network of cognitive radio (CR) employing non-orthogonal multiple access (NOMA) wireless networks over Rayleigh fading channels. The considered system model adopts device-to-device (D2D) transmission together with traditional communication to form a new system model, namely CR-D2DNOMA network. The specific user is selected from multiple D2D-Tx users (D2Ds) to communicate with far NOMA users to form qualified D2D connection with assistance of the Relay user ( R U ). The main metric in such CR-D2DNOMA network needs to be considered and we particularly introduce the closed-form expressions for outage probability in the secondary network where it is designed to serve two far NOMA users. The perfect Successive Interference Cancellation (SIC) and imperfect SIC can be further examined at the second NOMA user who detects signal based on the ability of SIC. The results show the positive impact of increasing the fading parameters on the system performance. More importantly, numerical results are provided to verify the correctness of our derivations. Additionally, the effects of asymptotic expressions on insights evaluation are also further analyzed.
    Materialart: Online-Ressource
    ISSN: 1424-8220
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2019
    ZDB Id: 2052857-7
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 10
    In: Sensors, MDPI AG, Vol. 19, No. 3 ( 2019-02-12), p. 736-
    Kurzfassung: In this paper, an Internet-of-Things (IoT) system containing a relay selection is studied as employing an emerging multiple access scheme, namely non-orthogonal multiple access (NOMA). This paper proposes a new scheme to consider secure performance, to be called relay selection NOMA (RS-NOMA). In particular, we consider metrics to evaluate secure performance in such an RS-NOMA system where a base station (master node in IoT) sends confidential messages to two main sensors (so-called NOMA users) under the influence of an external eavesdropper. In the proposed IoT scheme, both two NOMA sensors and an illegal sensor are served with different levels of allocated power at the base station. It is noticed that such RS-NOMA operates in two hop transmission of the relaying system. We formulate the closed-form expressions of secure outage probability (SOP) and the strictly positive secure capacity (SPSC) to examine the secrecy performance under controlling setting parameters such as transmit signal-to-noise ratio (SNR), the number of selected relays, channel gains, and threshold rates. The different performance is illustrated as performing comparisons between NOMA and orthogonal multiple access (OMA). Finally, the advantage of NOMA in secure performance over orthogonal multiple access (OMA) is confirmed both analytically and numerically.
    Materialart: Online-Ressource
    ISSN: 1424-8220
    Sprache: Englisch
    Verlag: MDPI AG
    Publikationsdatum: 2019
    ZDB Id: 2052857-7
    Standort Signatur Einschränkungen Verfügbarkeit
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