Search

Hot air generators are essential for food drying processes, operating in either indirect or direct modes. In this study, a high‐power radiant porous burner in a novel dual hot air generator (HAG‐D) was designed and experimentally investigated. Temperatures and emissions of the combustion process are reported for 9, 13, and 18 kW, and 20% and 40% of excess air. Indirect and direct modes were tested across airflow rates of 300–1100 m3/h to assess thermal efficiency. For indirect mode operation, 88% thermal efficiency is the highest value for 9 kW, 20% excess air, with an airflow of 890 m3/h observing air temperature difference (outlet minus inlet) of approximately 30°C. Furthermore, CO and NOx emissions were found in the range of 0–30 ppm and 20–45 ppm, respectively. For direct mode operation, results showed that for 18 kW with 20% and 40% excess air, the maximum thermal efficiency was 82% with an airflow of 670–1040 m3/h and air temperature difference in the range of 50–80°C. Results confirm that the radiant heat transfer mechanism allows for higher efficiencies and less pollution in a wide range of powers in the HAG‐D unit. The direct mode is recommended for food drying processes due to low exposure to flue gases, and the indirect mode is for other industrial applications due to its high efficiency. Future studies are suggested to assess renewable fuels, such as liquefied petroleum gas or natural gas and hydrogen mixtures, toward energy transition. Practical applications: The potential applications or practical benefits of the develop of this novel dual hot air generator is in the food industry, particularly in drying process of fruits and vegetables. Also, air conditioning, and space heating (household use) processes stand out among their several applications to generate hot air, such as paint, and wood. [ABSTRACT FROM AUTHOR]

Gli Scirtidae sono una famiglia di coleotteri acquatici allo stadio larvale, la cui conoscenza in Italia presenta ancora molte lacune. Fino ad ora per la provincia di Brescia erano note cinque specie appartenenti a due generi; nel presente contributo, principalmente frutto di campagne di raccolta svoltesi negli ultimi anni in territorio bresciano e aree immediatamente limitrofe, vengono segnalate 16 specie, suddivise in 7 generi. Di queste specie Odeles gredleri (Kiesenwetter, 1863) e Scirtes haemisphaericus (Linnaeus, 1767) risultano anche i primi dati di Scirtidae noti per la provincia di Bergamo, mentre Hydrocyphon deflexicollis (P.W.J. Müller) risulta nuova per la Lombardia. Per contro, Contacyphon pubescens (Fabricius, 1792) e C. kongsbergensis (Munster, 1924), note per l'area in esame da fonti bibliografiche datate, non sono state rinvenute nel corso delle campagne di ricerca; la seconda specie, inoltre, è segnalata di un biotopo di poco al di fuori della provincia di Brescia (Pian del Gembro) ma geograficamente facente parte del bacino idrografico dell'alto corso del fiume Oglio, in Valle Camonica. In aggiunta viene segnalata per la prima volta in Lombardia la presenza di Scirtes orbicularis (Panzer, 1793), da una località in provincia di Mantova. Per ogni specie viene fornita una mappa della distribuzione in provincia di Brescia e in alcuni comuni limitrofi. Viene introdotta anche una breve analisi corologica della scirtidocenosi dell'area in esame. [ABSTRACT FROM AUTHOR]

The diving beetle genus Rhithrodytes Bameul, 1989 is endemic to areas surrounding the Western Mediterranean Basin, and currently includes six lotic species; three each in Europe and North Africa. Here we describe a striking new species, Rhithrodytes pantaleonii sp. nov., discovered during recent fi eldwork in southwestern Sardinia. The new species differs markedly from the only previously known Rhithrodytes from the Tyrrhenian Islands, R. sexguttatus (Aubé, 1838). The pale, fl attened appearance of R. pantaleonii sp. nov., together with its small eyes and scarcity during collecting, all point to it being semisubterranean. A combination of mitochondrial and nuclear DNA sequences, obtained non-destructively from the holotype, allow us to reconstruct the evolutionary history and historical biogeography of this taxon and take the opportunity to publish the mitogenome of the new species. Rhithrodytes pantaleonii sp. nov. is shown to be sister to R. sexguttatus, these taxa apparently having diverged during the Miocene, when the Sulcis-Iglesiente region of southwestern Sardinia was separated from the rest of Corsico-Sardinia by the Sardinian Seaway. Our discovery adds to our understanding of the biogeography of the Tyrrhenian Islands, and further highlights the importance of the Sulcis-Iglesiente region as an area of endemism in its own right. [ABSTRACT FROM AUTHOR]

The present work is focused on the assessment of the performance and fine particulate matter emissions (PM2.5) of a turbocharged four-cylinder direct injection diesel engine operating under dual-fuel mode with Liquefied Petroleum Gas (LPG). For load levels of 30%, 60% and 100%, measurements were taken, keeping the engine speed constant at 2200, 2500 and 3200 rpm, while the engine knock detonation was detected through a non-invasive internal system. According to experimental measurements, the abnormal knock combustion occurred at full load operation with a maximum LPG energy fraction of ~60%. The brake fuel conversion efficiency increased by 2.6% with an LPG energy fraction of 10%, where a fuel saving of 11.9% was achieved with respect to the diesel-only operation. The reduction of diesel consumption was around 50% with respect to 100% diesel operation at full load operations, where the highest brake fuel conversion efficiency was achieved. The brake fuel conversion efficiency decreased as LPG addition increased for all the engine loads. Regarding emissions, PM2.5 decreased with the addition of LPG. However, HC and CO emissions increased as LPG injection was higher. NOx emissions and exhaust gas temperatures were reduced for operation with higher LPG fractions, except for full load levels at 2200 and 2500 rpm. [ABSTRACT FROM AUTHOR]

Mediterranean climate regions have become more vulnerable to fire due to the extreme weather conditions and numerous Eucalyptus globulus plantation areas. The aim of this study is to analyze the fire hazard related to E. globulus in a forest fire scenario, based on the contrast of thermochemical parameters and their relationship with chemical properties, considering the predominant exotic forest species (E. globulus, Pinus radiata, Acacia dealbata, and Acacia melanoxylon) present in the Valparaiso region, Chile. The results revealed that although all of the studied species were highly flammable, E. globulus was extremely flammable, as its leaves contain high concentrations of essential oils, monoterpenes, and sesquiterpenes, which can generate a flammable atmosphere due to their low flashpoint and the strong negative influence shown between the essential oils, volatile terpenes, and limonene concentration. Moreover, the heat of combustion of E. globulus was positively correlated with its high essential oil contents. Finally, all of the studied species had low flashpoints and high heating values; therefore, they are predisposed to ignite in the presence of a heat source, releasing high amounts of energy during combustion, which contributes to the risk of the formation and spread of canopy fires among these tree formations. [ABSTRACT FROM AUTHOR]

Copyright of Ciencia, Tecnología y Salud is the property of Ciencia, Tecnologia y Salud and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ciencia, Tecnología y Salud is the property of Ciencia, Tecnologia y Salud and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Wildfires in the Valparaíso region (Chile) account for one of the main threats to local biodiversity, ecosystem services and infrastructure. This study focused on producing an initial record of thermo- and physicochemical properties of local forest species. For this purpose, leaf samples of species found in the Peñuelas Lake National Reserve, namely Pinus radiata , Eucalyptus globulus , Acacia dealbata , Quillaja saponaria and Cryptocarya alba , were collected and analysed. Higher and lower heating value, flash point, density and moisture content tests were performed for each sample. Overall results showed that lower heating values measured for both native and exotic species could indicate a high energy release source in wildfires. However, differences in the flash point between species indicated that C. alba and E. globulus had a lower ignition resistance than other species tested, possibly due to a lower flash point. In contrast, Q. saponaria and A. dealbata had the highest flash point for native and exotic species respectively. Finally, all presented data and procedures were aimed at establishing a foundation for a national database of critical forest species properties to be used in wildfire simulation tools. This database will enhance forest fire management effectiveness in Chile. The thermo- and physicochemical properties of exotic and native species foliage were used to identify which species favour wildfires and their propagation in the Valparaíso region, Chile. [ABSTRACT FROM AUTHOR]