Prevalence and determinants of sex-specific dietary supplement use in a greek cohort

We describe the profile of dietary supplement use and its correlates in the Epirus Health Study cohort, which consists of 1237 adults (60.5% women) residing in urban north-west Greece. The association between dietary supplement use and demographic characteristics, lifestyle behaviors, personal medical history and clinical measurements was assessed using logistic regression models, separately for women and men. The overall prevalence of dietary supplement use was 31.4%, and it was higher in women (37.3%) compared to men (22.4%; p-value = 4.2−08). Based on multivariable logistic regression models, dietary supplement use in women was associated with age (positively until middle-age and slightly negatively afterwards), the presence of a chronic health condition (OR = 1.71; 95% CI, 1.18–2.46), lost/removed teeth (OR = 0.52; 95% CI, 0.35–0.78) and diastolic blood pressure (OR per 5 mmHg increase =0.84; 95% CI, 0.73–0.96); body mass index and worse general health status were borderline inversely associated. In men, dietary supplement use was positively associated with being employed (OR = 2.53; 95% CI, 1.21–5.29). A considerable proportion of our sample used dietary supplements, and the associated factors differed between women and men

Applications of the 3T Method and the R1 Formula as Efficiency Assessment Tools for Comparing Waste-to-Energy and Landfilling

The assessment of novel waste-to-energy technologies has several drawbacks due to the nature of the R1 formula. The 3T method, which aims to cover this gap, combines thermodynamic parameters in a radar graph and the overall efficiency is calculated from the area of the trapezoid. The present study expands the application of the 3T method in order to make it suitable for utilization in other energy-from-waste technologies. In the framework of this study, a 3T specialized solution is developed for the case of landfilling plus landfill gas recovery, with the potential inclusion of landfill mining. Numerical applications have been performed for waste-to-energy and landfilling by using both the R1 formula and the 3T method. The model Land GEM was used for the calculation of the total landfill gas. The Combined Heat and Power (CHP) efficiency of the landfill gas CHP efficiency was 16.6%–33.1%, and for the waste-to-energy plant, the CHP efficiency was over 70%. The full range of parameters, like metal recovery and quality of CHP, were not fully reflected by the R1 formula, which returned values of 1.07 for waste-to-energy and from 0.37 to 0.63 for different landfilling scenarios. Contrary to that, the 3T method calculated values between 0.091 and 0.307 for the waste-to-energy plant and values between 0.011 and 0.121 for the various landfilling scenarios. The 3T method is able to account for the recovery of materials like metals and assess the quality of the output flows. The 3T method was able to successfully provide a solution for the case of landfilling plus landfill gas recovery, with the potential inclusion of landfill mining, and directly compares the results with the conventional case of waste-to-energy

Multicriteria analysis as a supporting decision tool for expanding the use of the 3T method for waste-to-energy technologies and biorefineries

The advancement of Circular Economy practices has accelerated the development of recovery operations in waste management. Moreover, novel Waste-to-Energy (WtE) plants go well beyond the conventional framework of Combined Heat and Power (CHP) production and have also focused on the recovery of metals or the secondary production of other products. Thus, an integrated methodology needs to be utilised for the holistic assessment of novel WtE plants. The previously introduced 3T Method is a thermodynamic approach that assesses not only the CHP efficiency but also the quality of the recovered materials/products. Nonetheless, this method operates optimally in net energy producing facilities. This study introduces an outranking multicriteria decision analysis (MCDA) method that incorporates the 3T method and can be used for the assessment of WtE plants that produce valuable materials (like gasification plants) and biorefineries. The thermodynamic parameters that are used in the 3T Method were integrated in a MCDA tool based on the PROMETHEE-GAIA methods and five WtE plants were analysed. The proposed tool successfully assessed the production of materials from Plant D with Phi flows of 0.4583 and 0.3682 for scenarios 1 & 2, while also evaluating positively the high CHP efficiency of Plant C with Phi flows of 0.0417 and 0.0864, respectively. Overall, the PROMETHEE-GAIA MCDA tool kept most of the positive attributes of the 3T Method, while enhancing at the same time the role of materials in the assessment process. This proposed tool can develop to be a useful method for assessment for biorefineries

The Role of Hydrogen and H₂ Mobility on the Green Transition of Islands: The Case of Anafi (Greece)

The holistic green energy transition of non-interconnected islands faces several challenges if all the energy sectors are included, i.e., electricity, heating/cooling, and mobility. On the one hand, the penetration of renewable energy systems (RES) is limited due to design restrictions with respect to the peak demand. On the other hand, energy-intensive heating and mobility sectors pose significant challenges and may be difficult to electrify. The focus of this study is on implementing a hybrid Wind–PV system on the non-interconnected island of Anafi (Greece) that utilizes surplus renewable energy production for both building heating through heat pumps and hydrogen generation. This comprehensive study aims to achieve a holistic green transition by addressing all three main sectors—electricity, heating, and transportation. The produced hydrogen is utilized to address the energy needs of the mobility sector (H2 mobility), focusing primarily on public transportation vehicles (buses) and secondarily on private vehicles. The overall RES production was modeled to be 91,724 MWh with a RES penetration of 84.68%. More than 40% of the produced electricity from RES was in the form of excess electricity that could be utilized for hydrogen generation. The modeled generated hydrogen was simulated to be more than 40 kg H2/day, which could cover all four bus routes of the island and approximately 200 cars for moderate use, i.e., traveled distances of less than 25 km/day for each vehicle

Biomass Potential from Agricultural Waste for Energetic Utilization in Greece

The alignment of the Greek national legislation with the corresponding EU legislation has enhanced the national efforts to pursue renewable Combined Heat and Power (CHP) projects. The scope of the present study has been the identification of the available biomass resources and the assessment of their potential. In this paper, we present the results from the administrative regions of Crete, Thessaly, and Peloponnese. The levels of lignocellulosic biomass in Greece are estimated to be 2,132,286 tonnes on an annual basis, values that are very close to the cases of other Mediterranean countries like Italy and Portugal. In respect to the total agricultural residues, Crete produces 1,959,124 tonnes/year and Thessaly produces 1,759,457 tonnes/year. The most significant streams are identified to be olive pits, olive pruning, and cotton ginning remnants, with more than 100,000 tonnes/year each. In the latter part of this manuscript, a case study is presented for the development of a CHP gasification facility in Messenia. The biomass energy potential of the area is very promising, with about 3,800,000 GJ/year. The proposed small-scale gasification technology is expected to utilize 7956 tonnes of biomass per year and to produce 6630 MWh of electricity and 8580 MWh of thermal energy

Quality of Hydrochar from Wine Sludge under Variable Conditions of Hydrothermal Carbonization: The Case of Lesvos Island

Lesvos island has several food and beverage production industries and the valorization of their waste has been an unexplored task. The focus of this study is the valorization of wine sludge which is a very interesting waste stream due to the high phenolic content. This study identified all the operating wineries on the island and sampled local wine sludge. Hydrothermal carbonization (HTC) was utilized for the valorization of wine sludge and the production of hydrochar and liquid HTC liquor. The experiments had a residence time of 24 h and were performed at 200 °C. Except the uniqueness of wine sludge as a utilized material, this study performed HTC under different pressure regimes that were developed by different filling percentages of the reactor, i.e., 24–48%. The different pressure regimes influenced the measured parameters of both the liquid and the solid products of HTC. The Chemical Oxygen Demand (COD) ranged between 230 and 280 g/L with the maximum reduction was observed at a filling percentage of 32%. At the same time, lower filling percentages favored the total phenolic content (max value: 21 g/L) and higher filling percentages favored the Higher Heating Value (HHV) of the hydrochar (max value: 20.36 MJ/Kg) and the produced mass yield of hydrochar (max value: 234.3 mg). For all cases, low pH values were measured on the liquid fraction and this can be attributed to the presence of organic acids. Future work will focus on the characterization of the specific phenolic content of the liquid fraction

Operation and Thermodynamic Modeling of a Novel Advanced Hydrothermal Reactor: Introduction of the Novel 3-Step Evolution Model

Liquid biowaste represents more than 98% of the total municipal waste streams on wet basis and 4–5% on dry basis. Recent attention has been focused on how to manage it optimally, and several novel technologies are being developed to valorize it. Among the developing alternatives is a technology that operates continuously by integrating a hydrothermal reactor, a gasifier and condenser to recover hydrochar using any produced gases to power the system. This study introduces the “3-step evolution model” in order to simulate the hydrothermal reactor. The model has been developed in a MATLAB/Cantera environment and calculates the outputs as the products of a series of sub-stoichiometric char-gas reactions. Experiments with chicken manure slurry as feedstock were implemented for the validation of the model. Treatment of 32.16 kg/h of chicken manure produces 4.57 kg/h of hydrochar and 3.45 kg/h of syngas. The 3-step evolution model simulated the correct ratio of solid-to-gas, 57–43% (excluding the liquids). The experimentally measured carbon dioxide is used as a correction factor to calculate all the other parameters that cannot be assessed during the continuous operation of the hydrothermal reactor. The simulated compositions for carbon dioxide and methane were 94–96% and 0.5–0.8%, respectively. The values were close to the experimental results that ranged from 94.7% to 95.6% for the carbon dioxide and from 0.5% to 0.7% for the methane. The model predicts that higher temperatures of operation would increase carbon monoxide composition from 4–5% up to 7–8%

Προσομοιωμένη ανόπτηση στο πρόβλημα δρομολόγησης οχημάτων με πολλαπλές επιστροφές στην αποθήκη

Πτυχιακή Εργασία που υποβλήθηκε στην σχολή ΜΠΔ του Πολ. Κρήτης για την πλήρωση προϋποθέσεων λήψης Πτυχίου.Περίληψη: Η παρούσα πτυχιακή εργασία δύναται να επιλύσει ένα πρόβλημα δρομολόγησης οχημάτων με σκοπό την εύρεση της βέλτιστης διαδρομής που θα ακολουθηθεί. Η βέλτιστη διαδρομή εξαρτάται από μεταβλητές όπως ο χρόνος, η συνολική απόσταση και το κόστος. Το πρόβλημα ανάγεται σε δρομολόγηση οχημάτων με πολλαπλές επιστροφές στην αποθήκη το οποίο περιλαμβάνει ορισμένους περιορισμούς κατά τη μοντελοποίηση, οι οποίοι λαμβάνονται υπόψιν κατά την εύρεση της βέλτιστης λύσης. Η αρχική λύση θα βρεθεί με τον αλγόριθμο των εξοικονομήσεων των Clarke & Wright. Συγκεκριμένα θα διαμορφωθεί μια αρχική διαδρομή η οποία θα βρίσκεται εντός των περιορισμών χωρίς να είναι βέλτιστη. Για την εύρεση της βέλτιστης λύσης θα ληφθεί η πρώτη λύση και στην συνέχεια θα χρησιμοποιηθεί ο αλγόριθμος της προσομοιωμένης ανόπτησης με σκοπό την βελτίωσή της, επίσης θα γίνει εφαρμογή τοπικών αναζητήσεων έτσι ώστε να βελτιωθεί περαιτέρω η λύση (2-opt, 1-1 exchange, 1-0 relocate). Η υλοποίηση των αλγορίθμων θα γίνει μέσω της Matlab και στην συνέχεια τα αποτελέσματα θα αναλυθούν. Η χρησιμότητα της εργασίας ανάγεται στην ευκολία που προσδίδει σε μελλοντικές χρήσεις για την εύρεση της καλύτερης διαδρομής ενός προβλήματος δρομολόγησης οχημάτων σε μικρό χρόνο και με μικρό υπολογιστικό κόστος