Towards circular economy solutions for the management of rice processing residues to bioenergy via gasification

An economic assessment of two circular economy scenarios of fluidized bed gasification-based systems for combined heat and power (CHP) generation, fueled with rice processing wastes, was conducted. In the first scenario, the gasification plant with a capacity of 42,700 t/y of rice husks provides a waste management solution for 5 small rice processing companies, located at the same are, while in the second scenario the gasification unit of 18,300 t/y capacity provides a waste management solution to only one rice processing plant, being a custom-made solution. The first scenario is the most economically viable, with an annual revenue of 168 €/(t*y), very good payout time (POT=1.05) and return in investment (ROI=0.72). The economic assessment was based on experiments performed at a laboratory-scale gasification rig, while the economic analysis was based on the SMARt-CHP technology, developed at Aristotle University, Greece. The experimental proof of concept of rice husks waste gasification was studied at a temperature range 700-900oC, under an under-stoichiometric ratio of O2/N¬¬2 (10/90 v/v), as gasification agent. Producer gas’s LHV maximized at 800oC (10.9 MJ/Nm3), while the char’s BET surface reached a max of 146 m2/g at 900oC. Recommendations were also provided for a potential pretreatment of rice husks in order to minimize de-fluidization problems of the gasification system

Integrating UAV Multispectral Indices (NDVI) with Yield Data for Optimizing Flax (Linum usitatissimum L.) Cultivation

Flax (Linum usitatissimum L.), is a multipurpose crop, grown for fiber, seeds, and oil. This study aims to assess flax growth dynamics and agronomic traits using Normalized Difference Vegetation Index (NDVI) maps generated from multispectral imagery captured by an Unmanned Aerial Vehicle (UAV). Conducted at the Agricultural University of Athens, the field experiment followed a split-plot design with four replicates, encompassing various sowing distances (30 and 40 cm, between rows) and fertilization treatments (urea fertilization, urea with inhibitors, organic fertilizer). NDVI index maps were produced at key growth stages (60, 90, 120, 150, and 179 Days After Sowing) to facilitate comprehensive growth analysis. The findings indicate that while fertilization treatments and sowing densities influenced early growth stages, no significant differences were observed post 90 DAS. NDVI values correlated with agronomic traits, particularly during the early vegetative phase, highlighting the potential of UAV-based NDVI mapping for precise flax cultivation monitoring

Effect of Topping on Growth Development and CBD Content of Hemp (Cannabis sativa L.) in Pot Culture

In hemp (Cannabis sativa L.) cultivation, an important management factor is apical cut (topping) as this modulates plant architecture, plant biomass allocation as well as the yield of inflorescences and cannabinoids per plant and area. This study aimed to evaluate the effect of topping treatment on agronomical and quality characteristics of two monoecious hemp varieties, ‘Fedora 17’ and ‘Felina’, A greenhouse pot experiment was laid out in a completely randomized design (CRD), with two topping treatments (untreated and topped). The results revealed that plant height of both varieties was negatively affected by topping treatment and the higher values were recorded in the untreated (137.02 and 134.56 cm for Fedora 17 and Felina, respectively). The highest values of dry weight per plant and bud dry weight per plant were noticed for topped plants. In conclusion, the findings of the present study implied that the hemp had a positive response to applied topping for all studied cultivars and the CBD content was higher in topped plants as topping stress increased cannabidiol (CBD) content

Evaluation of Greenhouse Gas Emissions of Quinoa Seed Production in Greece

Population growth has led to an increase in food production, resulting in an increase in agricultural products in terms of quantity and quality. Quinoa (Chenopodium quinoa Willd.) cultivation is prevalent in most areas of the world due to its high-quality grain and its potential to produce high yields under tough growing conditions. This study aimed to investigate all greenhouse gas (GHG) emissions generated by quinoa seed production in Greece and their relationship with farm-related factors, from fertilizer production to energy consumption for all cultivation techniques. The amount of all GHG emissions was estimated using Cool Farm Tool software. In order to collect data, a questionnaire including questions regarding cultivation details, soil characteristics, inputs, fuel, and water use was distributed and completed by forty quinoa producers from Central Greece. Accordingly, the estimated carbon footprint values per hectare and per kilogram of quinoa seed were 1,159.65 and 0.48 kg CO2-eq, respectively. The present research also found that the highest CO2-eq emissions per kilogram of quinoa seed were found to be associated with the production of fertilizers, with a value of 0.20 kg CO2-eq corresponding to 40.88% of the total emissions per kilogram of produced seed. Consequently, attention must be given for the mitigation of the environmental impact of quinoa seed production. It is particularly important to manage chemical fertilizers and agricultural machinery properly in order to ensure the sustainable cultivation of quinoa

Wearable devices for assessing function in Alzheimer’s disease: a European public involvement activity about the features and preferences of patients and caregivers

Background: Alzheimer's Disease (AD) impairs the ability to carry out daily activities, reduces independence and quality of life and increases caregiver burden. Our understanding of functional decline has traditionally relied on reports by family and caregivers, which are subjective and vulnerable to recall bias. The Internet of Things (IoT) and wearable sensor technologies promise to provide objective, affordable, and reliable means for monitoring and understanding function. However, human factors for its acceptance are relatively unexplored. Objective: The Public Involvement (PI) activity presented in this paper aims to capture the preferences, priorities and concerns of people with AD and their caregivers for using monitoring wearables. Their feedback will drive device selection for clinical research, starting with the study of the RADAR-AD project. Method: The PI activity involved the Patient Advisory Board (PAB) of the RADAR-AD project, comprised of people with dementia across Europe and their caregivers (11 and 10, respectively). A set of four devices that optimally represent various combinations of aspects and features from the variety of currently available wearables (e.g., weight, size, comfort, battery life, screen types, water-resistance, and metrics) was presented and experienced hands-on. Afterwards, sets of cards were used to rate and rank devices and features and freely discuss preferences. Results: Overall, the PAB was willing to accept and incorporate devices into their daily lives. For the presented devices, the aspects most important to them included comfort, convenience and affordability. For devices in general, the features they prioritized were appearance/style, battery life and water resistance, followed by price, having an emergency button and a screen with metrics. The metrics valuable to them included activity levels and heart rate, followed by respiration rate, sleep quality and distance. Some concerns were the potential complexity, forgetting to charge the device, the potential stigma and data privacy. Conclusions: The PI activity explored the preferences, priorities and concerns of the PAB, a group of people with dementia and caregivers across Europe, regarding devices for monitoring function and decline, after a hands-on experience and explanation. They highlighted some expected aspects, metrics and features (e.g., comfort and convenience), but also some less expected (e.g., screen with metrics)

Combined Effect of Biocompost and Biostimulant on Root Characteristics of Cannabis sativa L.

The use of earthworms in bio-composting (vermicomposting) is gaining popularity as a bio-waste management approach for producing nutrient-rich organic fertilizer. Furthermore, the use of seaweed extracts as biostimulants changes the physical, biochemical, and biological aspects of the soil, as well as the architecture of plant roots, allowing for more effective nutrient uptake and increasing plant development and yields. This study aimed to evaluate the combined effect of biocompost and biostimulant on the development of the root system of cannabis (Cannabis sativa L.) plant. An outdoor pot experiment was set up a completely randomized design, with four treatments including vermicompost, vermicompost amended with seaweed-based biostimulant, vermicompost mixed with spent mushroom substrate (SMS) and cattle manure (CM) compost, and vermicompost mixed with SMS+CM compost and amended with seaweed-based biostimulant. The results revealed that the highest values of root length density, root diameter, and nitrogen content in roots (1.36 cm cm-3, 1.29 mm, and 1.23%, respectively) were found in plants grown in the substrate of vermicompost mixed with SMS+CM compost and amended with seaweed-based biostimulant, pointed this out as a recommended treatment for increased biomass production, which is important in the processing of cannabis for medicinal purposes