The heat supply object thermal regime under conditions of gas infrared emitter and air exchange system joint operation

The paper presents the results of experimental studies on the formation of thermal comfort conditions in large premises with the joint operation of gas infrared emitters and air exchange ventilation system. The values of temperatures and heat fluxes on the clothing surface under natural and mixed convection conditions were obtained. It has been established that the air exchange system operation in the premises reduces the temperature drop of the person clothes surface, respectively, a more favorable temperature condition is achieved in the working area.

Effects of Different Temperatures on the Antibacterial, Immune and Growth Performance of Crucian Carp Epidermal Mucus

Fish is one of the important sources of energy and protein, and proper water temperature is key to successful fish breeding. The authors of this study evaluated crucian carp growth, mucus antibacterial properties, and immune indicators at 17, 21, 24, 27, and 31 °C. The results indicated that in the range of 17–31 °C, the resistance of epidermal mucus to Vibrio harveyi decreased with temperature rising. At 24 and 27 °C, the activities of lysozyme and catalase significantly increased; alkaline phosphatase activity, superoxide dismutase activity, and total protein concentration first increased and then decreased with rising temperature; the highest values were observed at 24 °C, with increases of 56.55%, 26.64%, and 44.52%, respectively, compared to those under the 17 °C treatment. When the treatment reached 27 °C, the temperature had an effect on the growth and antibacterial properties of crucian carp, and the activities of alkaline phosphatase and superoxide dismutase were significantly reduced. At temperatures of 17–24 °C, the survival rate of crucian carp could reach more than 93%, and at the temperature of 24 °C, the specific growth rate reached the highest value of 43.29%. Therefore, the most favorable temperature for the long-term breeding of crucian carp was found to be 24 °C. This study provides a favorable experimental basis for the establishment of intelligent aquaculture systems and the setting of water environment parameters.

Ground-based “Pot-in-Pot” system and its effectiveness in growing Thuja occidentalis “Smaragd” planting material in a nursery

For the sparsely wooded regions of Russia, and in particular, the Central forest-steppe, new technologies for growing seedlings and seedlings of tree species are extremely important. It provids rapid growth and high survival rate, which is compared to classic technologies. The purpose of our experiment was to establish the effect of temperature screens from pots of various sizes on the temperature in the root zone of the substrate, and, as a consequence, on the growth and productivity of Thuja occidentalis “Smaragd” in plastic pots for three seasons. The most favorable temperature conditions for plants are formed in large pots, which is facilitated by smooth temperature drops in the substrate and a large area of contact between the substrate and the root system. Agrotechnical methods of growing plants have shown the main advantages of “Pot-in-Pot” technology. This is accelerated plant growth due to more efficient use of water and fertilizers on a specially prepared substrate under conditions of minimal temperature fluctuations. Plants, especially large ones, will have a favorable presentation due to better leafing, a well-developed crown, and a large crown diameter. High safety during wintering also increases the efficiency of the technology providing a higher yield and subsequent more intensive growth.

Oscillation, synchrony, and multi-factor patterns between cereal aphids and parasitoid populations in southern Brazil

In different parts of the world, aphid populations and their natural enemies are influenced by landscapes and climate. In the Neotropical region, few long-term studies have been conducted, maintaining a gap for comprehension of the effect of meteorological variables on aphid population patterns and their parasitoids in field conditions. This study describes the general patterns of oscillation in cereal winged aphids and their parasitoids, selecting meteorological variables and evaluating their effects on these insects. Aphids exhibit two annual peaks, one in summer–fall transition and the other in winter-spring transition. For parasitoids, the highest annual peak takes place during winter and a second peak occurs in winter–spring transition. Temperature was the principal meteorological regulator of population fluctuation in winged aphids and parasitoids during the year. The favorable temperature range is not the same for aphids and parasitoids. For aphids, temperature increase resulted in population growth, with maximum positive effect at 25°C. Temperature also positively influenced parasitoid populations, but the growth was asymptotic around 20°C. Although rainfall showed no regulatory function on aphid seasonality, it influenced the final number of insects over the year. The response of aphids and parasitoids to temperature has implications for trophic compatibility and regulation of their populations. Such functions should be taken into account in predictive models.

Influence of Temperature and Photoperiod on the Fecundity of Habrobracon hebetor Say (Hymenoptera: Braconidae) and on the Paralysis of Host Larvae, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae)

Studies were carried out in the laboratory to understand the optimum environmental conditions at which the ectoparasitoid, Habrobracon hebetor Say (Hymenoptera: Braconidae), can paralyze and lay eggs when reared on the larvae of the stored product pest, Plodia interpunctella Hübner (Lepidoptera: Pyralidae). At the four temperatures investigated (20, 25, 30, and 35 °C), optimum temperatures for oviposition were found to be 25 and 30 °C, while 35 °C was the least favorable temperature. No significant differences were found between the percentages of diapausing and non-diapausing larvae paralyzed by the wasp at the temperatures of 20, 25, 30, 35 °C within 5 days. However, in another experiment that investigated the effect of photoperiods at different temperatures that included 15, 19 and 28 °C, the number of paralyzed larvae was highly reduced at low temperatures (15 °C) but photoperiods had no significant impact on the number of host larvae paralyzed. In addition, observations at short time intervals also showed that lower temperatures slowed down host larvae paralysis. The results suggest that H. hebetor can paralyze host larvae of P. interpunctella more efficiently and deposit more eggs at temperatures within the range of 20–30 °C.

Phaseolus beans (Leguminosae, Phaseoleae): a checklist and notes on their taxonomy and ecology

This work presents an updated list of the species belonging to the genus Phaseolus following its definition of 1978; it is the outcome of the study of eighty-six herbaria and forty-one explorations in the field in the period 1978–2019. There are currently eighty-one species, all of them native to the Americas, most of them distributed north of Panama (the genus is a migrant into South America), and half of them being known by very few records. They thrive in warm to mild temperate, seasonally dry, open forest, with rains under favorable temperature, from sea level up to 3,000 m. The recent increase in the number of recognized species is due to the endemic ones; this in combination with few unclassified specimens may indicate that the total number of species is not final yet, and that field work will be rewarding.

Monitoring of mineral nitrogen concentration as a possible factor of influence on the results of valvometry of mussel kept in non-flow conditions with food deficiency

We investigated changes in the content of mineral forms of nitrogen formed as a result of mussel vital activity in non-flow conditions under favorable temperature and aeration, but with food deficiency, as a possible factor influencing mussel flap movement and valvometry results. A laboratory 11-day experiment was carried out with mussels 24–26 mm long. The dry weight of their soft tissues was about 35 mg. The experiment consisted of five exposures lasting 17-67 h. The mussels were kept in 3-liter vessels with 3 individuals in each, feeding only on the natural food available in this volume of water. In parallel, vessels with aerated water without mussels in them were exposed. Ammonium, nitrite, and nitrate concentrations were measured at the beginning (i.e., in fresh seawater from the Sevastopol coastal zone) and at the end of each exposure. It was determined that, compared to the initial level at the end of the exposures, on average, the content of ammonium in vessels with mussels increased by 250%, nitrite – by 25%, and nitrate – did not change. In vessels without mussels, the content of ammonium, on average, decreased by 250 %, changes in the level of nitrite and nitrate corresponded to changes in the concentration of these nitrogen forms in vessels with mussels. The greatest variability was characteristic of the final values of ammonium concentration, in some exposures it could increase by 700 %. However, the maximum value of ammonium content during the experiment reached only 21, 7 μg N/l, which is two orders of magnitude lower than its MPC level for marine fishery objects. It follows from the obtained data that in experiments with mussels kept in non-flow conditions with food deficiency, the probability of the effect of ammonium excreted by them, as well as of products of its further biological oxidation on valvometry results is not high.

Slime control in paper mill using biological agents as biocides

The environmental conditions of paper mills are suitable for the growth of slime-forming microorganisms due to the supply of nutrients, favorable temperature, and moisture. The slime formation causes the spoilage of raw materials & additives, breaks in the paper during papermaking, loss of production, reduces the hygienic quality of the end products, produces off-spec and rejected products, creates microbiological corrosion, and produces harmful gases. The main microorganisms are Bacteria (mainly Bacillus spp., Achromobacter spp., Enterobacter spp., Pseudomonas spp., Clostridium, etc.), Fungi (Aspergillus, Penicillium, Saccharomyces, etc.), and Algae. Besides the use of conventional toxic chemical biocides or slimicides, slime formation can also be controlled in an eco-friendly way using enzymes, bacteriophages, biodispersants, and biocontrol agents alone or along with biocides to remove the slime. Enzymes have shown their effectiveness over conventional chemicals due to nontoxic and biodegradable nature to provide clean and sustainable technology. Globally enzymes are being used at some of the paper mills and many enzymatic products are presently being prepared and under the trail at laboratory scale. The specificity of enzymes to degrade a specific substrate is the main drawback of controlling the mixed population of microorganisms present in slime. The enzyme has the potential to provide the chemical biocide-free solution as a useful alternative in the future with the development of new technologies. Microorganisms control in the paper mill may appear as a costly offer but the cost of uncontrolled microbial growth can be much higher leading to slime production and large economic drain.

Design, Fabrication, and Performance Analysis of an Automatic Horizontal Egg Incubator

This research paper presents the design, construction, and performance testing of an automatic electrically powered egg incubator utilizing the horizontal placement of eggs. This experimental research was driven by the specific design and construction of a well-insulated rectangular egg-incubating box of dimension 400 mm × 600 mm × 500 mm and thickness 30 mm, where sample eggs were kept for experimental test analysis under the favorable temperature and humidity inside the box, which was automatically controlled. The device was made to operate under the temperature range of 37°C – 38°C, which was found to be adequate for developing embryos and also maintaining relative humidity at the range of 45–60% for the first 18 days and 60–90% for the last three days. Finally, in this machine, the egg tray was adjusted horizontally, and a motor clamped mechanism was used 5 times a day which was controlled automatically by a micro-controller for the motion of eggs up to 18 days of incubation. In conclusion, this egg-incubating machine has an efficiency and hatchability of 72.22%.