Automation of monitoring of drying parameters in hybrid solar-electric dryer for agricultural products

ABSTRACT Increasing the efficiency of solar dryers with ensuring that the system remains accessible to all users can be achieved with their automation through low-cost and easy-to-use technique sensors. The objective was to develop, implement and evaluate an automatic system for monitoring drying parameters in a hybrid solar-electric dryer (HSED). Initially, an automated data acquisition system for collecting the parameters of sample mass, air temperature, and relative air humidity was developed and installed. The automatic mass data acquisition system was calibrated in the hybrid solar-electric dryer. The automated system was validated by comparing it with conventional devices for measuring the parameters under study. The data obtained were subjected to analysis of variance, Tukey test and linear regression at p ≤ 0.05. The system to turn on/off the exhaust worked efficiently, helping to reduce the errors related to the mass measurement. The GERAR Mobile App showed easy to be used since it has intuitive icons and compatibility with the most used operating systems for mobile devices. The responses in communication via Bluetooth were fast. The use of Arduino, a low-cost microcontroller, to automate the monitoring activity allowed estimating the mass of the product and collecting the drying air temperature and relative air humidity data through the DHT22. This sensor showed a good correlation of mass and air temperature readings between the automatic and conventional system, but low correlation for relative air humidity. In general, the automatic data acquisition system monitored in real time the parameters for drying agricultural products in the HSED.

Influence of Impregnation with Modified Starch of a Paper Core on Bending of Wood-Based Honeycomb Panels in Changing Climatic Conditions

The main objective of the study was to determine the effect of impregnation of the paper core with acetylated starch on the mechanical properties and absorbed energy in the three-point bending test of wood-based honeycomb panels under varying temperatures and relative air humidity conditions. Nearly six hundred beams in various combinations, three types of facings, three core cells geometries, and two paper thicknesses were tested. The experiment results and their statistical analysis prove a significant relationship between the impregnation of paper with modified starch and mechanical properties. The most effective in absorbing energy, the honeycomb panels, consisted of a core with a wall thickness of 0.25 mm and a particleboard facing.

Effects of pretreatment, sowing time, sowing environment and climate factors on germination in Acer pseudoplatanus L.

In this study, the effects of different sowing environment (greenhouse and nursery), pretreatment (cold moist stratification), different sowing time (autumn, spring and summer) and some climate factors (air temperature, relative air humidity, soil temperature and soil moisture) on the germination of Acer pseudoplatanus L. seeds were studied. Seeds were harvested from the tree located in the Karadeniz Technical University campus. Three different germination trials were carried out; (1) direct sowing in autumn after seed collection (Control), (2) sowing stratified seeds in spring (Stratification-1) and (3) sowing stratified seeds in summer (Stratification-2). During the germination trial processes, air temperature, relative air humidity, soil temperature and soil moisture were measured periodicaly. Thus, the germination percentage changes in different sowing environments have been established on the basis of some climate factors. Higher germination percentages were obtained in the autumn (Control) compared to the spring (Stratification-1) and summer (Stratification-2) sowings. The highest percentages of germination were ­determined in the control trials (70% in greenhouse and 58% in nursery). Obtained germination results based on different sowing times revealed secondary dormancy in Acer pseudoplatanus L. seeds. It has been determined that the mean germination time in the greenhouse (12 days) was shorter than the mean germination time in the nursery (18 days). In addition, the obtained results showed that stratification and sowing time have a positive effect on the mean germination time in the greenhouse. Because of getting the best germination rates, keeping some climate ­factors constant (21.0-24.9 °C air temperature; 17.0-19.9 °C soil temperature; 63.0-68.9% relative air humidity; 60.0-67.9% soil moisture) during the vegetative propagation practices in the greenhouse, should affect mass ­seedling production in Acer pseudoplatanus L.

Growth and toxin production of phomopsin A and ochratoxin A forming fungi under different storage conditions in a pea (Pisum sativum) model system

Phomopsins are mycotoxins mainly infesting lupines, with phomopsin A (PHOA) being the main mycotoxin. PHOA is produced by Diaporthe toxica, formerly assigned as toxigenic Phomopsis leptostromiformis, causing infections in lupine plants and harvested seeds. However, Diaporthe species may also grow on other grain legumes, similar to Aspergillus westerdijkiae as an especially potent ochratoxin A (OTA) producer. Formation of PHOA and OTA was investigated on whole field peas as model system to assess fungal growth and toxin production at adverse storage conditions. Field pea samples were inoculated with the two fungal strains at two water activity (aw) values of 0.94 and 0.98 and three different levels of 30, 50, and 80% relative air humidity.After 14 days at an aw value of 0.98, the fungi produced 4.49 to 34.3 mg/kg PHOA and 1.44 to 3.35 g/kg OTA, respectively. Strains of D. toxica also tested showed higher PHOA concentrations of 28.3 to 32.4 mg/kg.D. toxica strains did not grow or produce PHOA at an aw values of 0.94, while A. westerdijkiae still showed growth and OTA production.Elevated water activity has a major impact both on OTA and, even more pronouncedly, on PHOA formation and thus, proper drying and storage of lupins as well as other grain legumes is crucial for product safety.

Preparation and Characterization of Photocatalytically Active Antibacterial Surfaces Covered with Acrylic Matrix Embedded Nano-ZnO and Nano-ZnO/Ag

In the context of healthcare-acquired infections, microbial cross-contamination and the spread of antibiotic resistance, additional passive measures to prevent pathogen carryover are urgently needed. Antimicrobial high-touch surfaces that kill microbes on contact or prevent their adhesion could be considered to mitigate the spread. Here, we demonstrate that photocatalytic nano-ZnO- and nano-ZnO/Ag-based antibacterial surfaces with efficacy of at least a 2.7-log reduction in Escherichia coli and Staphylococcus aureus viability in 2 h can be produced by simple measures using a commercial acrylic topcoat for wood surfaces. We characterize the surfaces taking into account cyclic wear and variable environmental conditions. The light-induced antibacterial and photocatalytic activities of the surfaces are enhanced by short-term cyclic wear, indicating their potential for prolonged effectivity in long-term use. As the produced surfaces are generally more effective at higher relative air humidity and silver-containing surfaces lost their contact-killing properties in dry conditions, it is important to critically evaluate the end-use conditions of materials and surfaces to be tested and select application-appropriate methods for their efficacy assessment.

Effect of irradiation on the growth and rooting of a climbing rose in vitro

The article presents the influence of pulsed and continuous irradiation (400…780 nm) on in vitro growth of the climbing rose variety “Camelot” at the illumination of 80±5 mmol/(m2s), temperature - 24±10C, and the relative air humidity - 73±2%. It was found that the experimental led light (LED) pulsed phytoirradiator contributed to a significant increase in the leaf surface area during cultivation of climbing rose microstems in Gamborg’s nutrient medium, the average growth was 2.94 mm2 compared to 2.80 mm2 in the control. Pulse irradiation increases the reproducibility of climbing roses by 1.7 times, and also increases the rooting rate up to 96% compared to 82% in the control. Experimental LED phytoirradiator of continuous irradiation promoted an increase in the leaf surface area growth at the level of the control luminescent phytoirradiator, but also provided a significant increase in the reproduction factor and rooting rate of rose microstems. In the pulsed mode, phytoinstallations consume only 50% of the electricity compared to the continuous irradiation mode.

Experimental and Simulation of Solar Drying Cabinet with PCM and SiO2 Materials

Solar energy is a potential renewable source in Indonesia, especially for the drying process. The process needs a drying cabinet as a support component to store the drying product. A high-quality drying cabinet to store heat for a long time is needed. This research aims to compare the thermal performance of the drying cabinet without PCM (phase change material) and SiO2 materials or DC I (drying cabinet I) with the drying cabinet that uses PCM and SiO2 materials or DC II (drying cabinet II). The research was carried out by experimental and simulation to investigate thermal performance and fluid flow characteristics. The experiment was carried out inside the laboratory to set uniform initial parameters and the simulation using computational fluid dynamics software. The drying cabinet was modeled in 3D. The experiment result showed DC II had a higher air temperature and lowered relative air humidity for two hours than DC I. The simulation result showed air temperature differences and backflow in the air streamline in the DC II.

Occurrence of Biting Midges (Diptera: Culicoides) on Dairy Farms in Eastern Slovakia in Relation to Abiotic Factors

Within the scope of our research, we have performed 59 trapping sessions and collected 15,756 biting midges from 20 species at four farms (Kluknava, Ostrov, Turňa nad Bodovou and Zemplínska Teplica), The most frequent types of captured insects were representatives of the Avaritia subgenus, C. obsoletus/C. scoticus, representing on average 85.1 % (13,295 individuals) of the fauna of the biting midges, with the exception of the farm in Ostrov where this group represented only 41.7 % of the fauna. At this particular farm, the most frequently trapped insects belonged to the Culicoides subgenus (54.1 %), in particular the C. bysta, C. lupicaris, C. newsteadi, C. Pulicaris and C. Punctatus species. During the trapping sessions, we monitored factors affecting the number of trapped biting midges, such as the temperature, relative air humidity and airflow rate: the air temperature during the trapping of the biting midges ranged from 9.8 to 26.2 °C; the relative air humidity ranged from 35.1 to 100 %; and the air flow rate ranged from no wind to a wind velocity of 8.2 m.s-1. However, in the final evaluation, we failed to observe a statistically significant correlation between the air flow and the number of trapped biting midges. The largest amounts of biting midges were trapped at temperatures ranging from 15.8 to 24.6 °C and at a relative air humidity ranging from 54.2 % to 68.6 %. While monitoring the seasonal dynamics of the physiological conditions of biting midge females at the selected farms, we confirmed that during the period from June to August, the most frequently trapped females were parous (50.1 %; 7,826 individuals). In addition, nulliparous females comprised 43.8 % (6,842 individuals) and were continuously trapped throughout the season (April— November).

Environmental influence on Triatoma vitticeps occurrence and Trypanosoma cruzi infection in the Atlantic Forest of south-eastern Brazil

Trypanosoma cruzi requires a triatomine insect vector for its life cycle, which can be complex in different enzootic scenarios, one of which is the unique transmission network in the Atlantic Forest of south-eastern Brazil. In Espírito Santo (ES) State, highly infected Triatoma vitticeps are frequently reported invading domiciles. However, triatomines were not found colonizing residences and mammals in the surrounding areas did not present T. cruzi infection. To date, the biotic and abiotic variables that modulate T. vitticeps occurrence and T. cruzi infection in ES State are still unknown. The aim of this study was to identify the environmental variables that modulate their occurrence. Local thematic maps were generated for two response variables: T. vitticeps occurrence and T. cruzi infection. The following explanatory variables were tested: climate (temperature, relative air humidity and rainfall), altitude elevation, mammalian species richness as well as soil and vegetation types. Spatiotemporal distribution patterns and correlation levels between response and explanatory variables were assessed through spatial statistics and map algebra modelling. The central and southern mesoregions presented higher T. vitticeps and T. cruzi distributions and can be considered transmission hotspots. The explanatory variables that can explain these phenomena were relative air humidity, average temperature, soil type, altitude elevation and mammalian species richness. Algebra map modelling demonstrated that central and southern mesoregions presented the environmental conditions needed for T. vitticeps occurrence and T. cruzi infection. The consideration of environmental variables is essential for understanding the T. cruzi transmission cycle. Cartographic and statistical methodologies used in parasitology have been demonstrated to be reliable and enlightening tools that should be incorporated routinely to expand the understanding of vector-borne parasite transmission.

The obtaining potato microtubers on the basis of optimization of in vitro cultivation conditions

Search work for optimization of such conditions for in vitro cultivation of potatoes as photoperiod, volume of nutrient medium, choice of a source of carbohydrate nutrition and its concentration, as well as growth regulators of auxin and cytokinin nature, was carried out in 2018-2020. Potato microplants of early-ripening (Alena, Latona, Red-Scarlett), middle-early (Adretta, Charodei, Svitanok Kievsky) and mid-season (Naiada, Ladozhskiy, Skarb) varieties were cultivated at illumination of 75-85 mMol/m2 s-1, 6500 K, air temperature 22...25 °C, relative air humidity 70-75 % and photoperiod from 4 to 16 hours. The results of three years of research have shown that the Murashige-Skooga nutrient medium modified by the Russian Potato Research Center with a 6 % sucrose concentration in a volume of 10 ml per microplant and a 12-hour photoperiod were optimal for micro-tuberization during in vitro cultivation of potatoes of all ripeness groups. The interaction of these cultivation conditions made it possible to obtain an average of 2.5 pcs. of microtubers per microplant of early-ripening potato varieties, 2.4 pcs. - middle-early and 3.2 pcs. - mid-season varieties. Optimal methods of in vitro cultivation of potatoes served as the basis for a new technique for obtaining potato microtubers. If this method was followed, the share of microplants with microtubers of early-ripening varieties increased by 6 %, middle-early varieties - by 12 % and mid-season ones - by 9 %. In addition, the duration of the micro-tuberization period in middle-early varieties was reduced by 14 days, in early-ripening and mid-season potato varieties by 28 days. Microplants of early-ripening and middle-early potato varieties formed larger microtubers, while mid-season varieties were in the lead in terms of quantitative yield.