Applications and Development of LEDs as Supplementary Lighting for Tomato at Different Latitudes

High-tech greenhouses and artificial light applications aim to improve food production, in line with one of the sustainable development goals of the UN Agenda 2030, namely, “zero hunger”. In the past, the incandescent lamps have been used for supplementary lighting (SL) at higher latitudes to increase greenhouse production during the dark season. Light-emitting diodes (LED) have been replacing gas discharge and incandescent lamps, and their development is expanding SL applications in different agricultural scenarios (e.g., urban farming, middle latitudes). In fact, recent research on LED applications in Mediterranean greenhouses have produced encouraging results. Since middle latitudes have a higher daily light integral (DLI) than higher latitudes in the dark season and climate conditions influence the installed power load of greenhouses, LED installation and management in Mediterranean greenhouses should be different and less expensive in terms of investment and energy consumption. Accordingly, the aim of this review is to outline the state of the art in LED applications and development, with a focus on latitude-related requirements. Tomato was used as a representative crop

ORC cogeneration systems in waste-heat recovery applications

The performance of organic Rankine cycle (ORC) systems operating in combined heat and power (CHP) mode is investigated. The ORC-CHP systems recover heat from selected industrial waste-heat fluid streams with temperatures in the range 150°C-330°C. An electrical power output is provided by the expanding working fluid in the ORC turbine, while a thermal output is provided by the cooling water exiting the ORC condenser and also by a second heat-exchanger that recovers additional thermal energy from the heat-source stream downstream of the evaporator. The electrical and thermal energy outputs emerge as competing objectives, with the latter favoured at higher hot-water outlet temperatures and vice versa. Pentane, hexane and R245fa result in ORC-CHP systems with the highest exergy efficiencies over the range of waste-heat temperatures considered in this work. When maximizing the exergy efficiency, the second heat-exchanger is effective (and advantageous) only in cases with lower heat-source temperatures (< 250°C) and high heat-delivery/demand temperatures (> 60°C) giving a fuel energy savings ratio (FESR) of over 40%. When maximizing the FESR, this heat exchanger is essential to the system, satisfying 100% of the heat demand in all cases, achieving FESRs between 46% and 86%

Thermo-economic assessment of a olive pomace gasifier for cogeneration applications

A thermo-economic analysis of a combined heat and power (CHP) plant fed by syngas produced through the gasification of dry olive pomace is presented. The plant is composed by a 800 kWtdowndraft gasifier, a gas clean-up system, a 200 kWemicroturbine (MGT) and a heat recovery system to cogenerate hot water. Surplus heat is used to dry olive pomace from 50% to 17% wb moisture content. The plant is modeled in ASPEN Plus. Real data from experimental tests are used to calibrate the gasifier model, while the technical specification and performance of the CHP plant are collected from commercial plants in operation and data from manufacturers. Mass and energy balances are reported throughout the paper. The thermodynamic simulation of the biomass gasifier coupled to the MGT, the thermal and electrical conversion efficiency and temperature of cogenerated heat available are also presented. A thermo-economic assessment is then proposed, to investigate the economic profitability of this small scale CHP plant in the Italian energy policy scenario and considering the subsidies available for renewable electricity in the form of feed-in tariffs. For this purpose, the case study of base load CHP plant operation and heat supplied to different typologies of energy end user is assumed. The results allow quantifying the most influencing economic and technical factors that affect the performance and profitability of such investment and the bottlenecks that should be faced to facilitate a broader implementation of such CHP schemes for on site generation

Thermo-economic Assessment of Small Scale Biomass CHP: Steam Turbines vs ORC in Different Energy Demand Segments☆

AbstractThe energy performance and profitability of CHP plants, and the selection of the optimal conversion technology and size, are highly influenced by the typology of energy demand (load-duration curve, temperature of heat demand, heat and electricity load patterns). In the small scale range, where CHP can be particularly promising to match local heat and power demand, the technologies based on boilers coupled to steam turbines (ST) and bottoming Organic Rankine Cycle (ORC) can be operated in flexible mode to match the energy demand. This is particularly important when high temperature heat is required (i.e. industrial end users). In the case of solid biomass fired CHP, the boiler + ST/ORC option could be competitive with the alternatives of boiler + Stirling engine, externally fired GT or gasification + ICE. In this paper, a thermo-economic comparison of the following biomass-CHP configurations is proposed: (A) boiler + ST + bottoming ORC, (B) boiler + ST, (C) boiler + ORC and (D) configuration (A) with option to switch on or off the bottoming ORC on the basis of the heat demand available. The focus is on a 1 MWt biomass boiler, and the plants are operated to serve residential (r), tertiary (t) and industrial (i) heat and power demand. The thermodynamic cycles are modeled by Cycle-Tempo, while the energy demand is modeled through simplified indicators (temperature of heat demand, equivalent thermal demand hours). On the basis of the results of thermodynamic simulations, upfront and operational costs assessment, and Italian energy policy scenario (feed-in tariffs for biomass electricity), the global energy conversion efficiency and investment profitability is estimated, for each CHP configuration and energy demand segment. The results indicate the optimal CHP configuration for each end user and the key technical and economic factors in the Italian legislative framework

Environmental and Economic Analysis of an Anaerobic Co-Digestion Power Plant Integrated with a Compost Plant

Italian power generation through anaerobic digestion (AD) has grown significantly between 2009 and 2016, becoming an important renewable energy resource for the country, also thanks to the generous incentives for produced electricity available in the last years. This work focuses on the economic and environmental issues of AD technology and proposes a technoeconomic analysis of investment profitability without government support. In particular, the analysis focuses on an AD power plant fed by zootechnical wastewater and agro-industrial residues coupled to a cogeneration (CHP) system and a digestate-composting plant that produces soil fertilizers. We aim to determine the economic profitability of such AD power plants fed by innerfarm biomass wastes, exploiting digestate as fertilizer, using the cogenerated heat and taking into account the externalities (environmental benefits). Environmental analysis was carried out via a life cycle analysis (LCA), and encompassing the production of biogas, heat/electricity and compost in the downstream process. The un-released environmental emissions were converted into economic benefits by means of a stepwise approach. The results indicate that integrating a compost plant with a biogas plant can significantly increase the carbon credits of the process. The results were evaluated by means of a sensitivity analysis, and they report an IRR in the range of 6%–9% according to the Italian legislative support mechanisms, and possibilities to increase revenues with the use of digestate as fertilizer. The results significantly improve when externalities are included

The Threads of Biosystems Engineering

The core concepts, or threads, of Biosystems Engineering (BSEN) are variously understood by those within the discipline, but have never been unequivocally defined due to its early stage of development. This makes communication and teaching difficult compared to other well established engineering subjects. Biosystems Engineering is a field of Engineering which int egrates engineering science and design with applied biological, environmental and agricultural sciences. It represents an evolution of the Agricultural Engineering discipline applied to all living organisms not including biomedical applications. The basic key element for the emerging EU Biosystems Engineering program of studies is to ensure that it offers essential minimum fundamental engine ering knowledge and competences . A core curriculum developed by Erasmus Thematic Networks is used as benchmark for Agr icultural and Biosystems Engineering studies in Europe. The common basis of the core curriculum for the discipline across the Atlantic , including a minimum of competences comprising the Biosystems Engineering core competencies, has been defined by an Atlan tis project , but this needs to be taken further by defining the threads linking courses together. This paper presents a structured approach to define the Threads of BSEN . The definition of the mid-level competences and the associated learning outcomes has been one of the objectives of the Atlantis programme TABE.NET. The mid-level competences and learning outcomes for each of six specializations of BSEN are defined while the domain-specific knowledge to be acquired for each outcome is proposed. Once the proposed definitions are adopted, these threads will be available for global development of the BSEN

Effect of Citric Acid and Ethylenediaminetetraacetic Acid on the Surface Morphology of Young and Old Root Dentin

Introduction: The aim of this in vitro study was to evaluate the effect of 10% citric acid and 17% ethylenediaminetetraacetic acid (EDTA) irrigating solutions on the surface morphology of young and old root dentin by determining the number and diameter of dentinal tubules using scanning electron microscopy (SEM). Methods and Materials: Fifty healthy human teeth collected from young (≤30 years) and old (≥60 years) individuals (n=25) were first prepared with a Largo bur #2 to produce smear layer on the root canal surface. Subsequently, the crowns and the root middle and apical thirds were sectioned and removed, and the cervical thirds were sectioned vertically in the buccal-lingual direction into two equal halves. The obtained samples were then immersed in 2.5% sodium hypochlorite for 30 min and randomly separated into two treatment groups for each age group. In each age group, ten samples were selected as controls and did not receive any type of treatment. The rest of the specimens were then rinsed, dried and treated for 4 min with 10% citric acid or 17% EDTA. The samples were then assessed with SEM regarding the number and diameter of dentinal tubules. All data were assessed using Student’s t-test. The level of significance was set at 0.05. Results: Regardless of the type of treatment, no significant differences were observed in the number of open tubules between the young and old root dentin (P>0.05). Nonetheless, the diameter of the tubules in the old root dentin was larger when 17% EDTA was used (P<0.05). Both, young and old root dentin did not differ with the 10% citric acid treatment (P>0.05). Conclusion: The results showed that 17% EDTA treatment induced a significant demineralization in old root dentin.Keywords: Citric Acid; Dentinal Tubule; Ethylenediaminetetraacetic Acid; Scanning Electron Microscopy; Surface Morpholog

A new case of de novo 6q24.2-q25.2 deletion on paternal chromosome 6 with growth hormone deficiency: A twelve-year follow-up and literature review

BACKGROUND: Deletions on the distal portion of the long arm of chromosome 6 are relatively uncommon, and only a small number occurs in the paternal copy, causing growth abnormalities. As a result, extensive clinical descriptions are lacking. CASE PRESENTATION: We describe a male of Italian descent born at 35 weeks by elective caesarean delivery presenting hypoplastic left colon, bilateral inguinal hernia, dysplastic tricuspid and pulmonary valves, premature ventricular contractions, recurrent otitis media, poor feeding, gastro-oesophageal reflux, bilateral pseudopapilledema, and astigmatism. He also showed particular facial dysmorphisms and postnatal growth failure. Early psychomotor development was mildly delayed. At 3.75 years, he was evaluated for severe short stature (−2.98 SD) and delayed bone age. He showed an insulin-like growth factor 1 concentration (IGF-1) in the low-normal range. Growth hormone stimulation tests showed a low response to clonidine and insulin. Magnetic resonance imaging showed hypophyseal hypoplasia. Genetic evaluation by Single Nucleotide Polymorphism arrays showed a de novo 6q24.2-q25.2 deletion on paternal chromosome 6. CONCLUSION: We confirm that this is a new congenital malformation syndrome associated with a deletion of 6q24.2-q25.2 on paternal chromosome 6. We suggest evaluating the growth hormone axis in children with 6q24.2-q25.2 deletions and growth failure

Techno-Economic Analysis of ZnO Nanoparticles Pretreatments for Biogas Production from Barley Straw

The aim of this study was to analyze the effect of ZnO nanoparticles (ZnO NPs) on the biogas production from mechanically treated barley straw and to perform a techno-economic analysis based on the costs assessment and on the results of biogas production. The structural changes of mechanically pretreated barley straw were observed using FTIR, XRD, TGA, and SEM. Additionally, both green ZnO NPs prepared from red alga (Antithamnion plumula) extract and chemically prepared ZnO NPs were characterized by FTIR, XRD, SEM, and TEM, surface area, and EDX. The results revealed that the biogas production was slightly improved by 14.9 and 13.2% when the barley straw of 0.4 mm was mechanically pretreated with 10 mg/L of both green and chemical ZnO NPs and produced 390.5 mL biogas/g VS and 385 mL biogas/g VS, respectively. On the other hand, the higher concentrations of ZnO NPs equal to 20 mg/L had an inhibitory effect on biogas production and decreased the biogas yield to 173 mL biogas/g VS, which was less than the half of previous values. It was also clear that the mechanically treated barley straw of 0.4 mm size presented a higher biogas yield of about 340 mL/g VS, in comparison to 279 mL biogas/g VS of untreated biomass. The kinetic study showed that the first order, modified Gompertz and logistic function models had the best fit with the experimental data. The results showed that the nanoparticles (NPs) of the mechanically treated barely straw are a suitable source of biomass for biogas production, and its yields are higher than the untreated barley straw. The results of the cost-benefit analysis showed that the average levelized cost of energy (LCOE), adopting the best treatments (0.4 mm + 10 mg/L ZnO), is 0.21 €/kWh, which is not competitive with the other renewable energy systems in the Egyptian energy market