Larval Development in Tropical Gar (Atractosteus tropicus) Is Dependent on the Embryonic Thermal Regime: Ecological Implications under a Climate Change Context

In ectotherm species, environmental temperature plays a key role in development, growth, and survival. Thus, determining how temperature affects fish populations is of utmost importance to accurately predict the risk of climate change over fisheries and aquaculture, critical to warrant nutrition and food security in the coming years. Here, the potential effects of abnormal thermal regimes (24, 28 and 32 °C; TR24, TR28, and TR32, respectively) exclusively applied during embryogenesis in tropical gar (Atractosteus tropicus) has been explored to decipher the potential consequences on hatching and growth from fertilization to 16 days post-fertilization (dpf), while effects on skeletal development and body morphology were explored at fertilization and 16 dpf. Egg incubation at higher temperatures induced an early hatching and mouth opening. A higher hatching rate was obtained in eggs incubated at 28 °C when compared to those at 24 °C. No differences were found in fish survival at 16 dpf, with values ranging from 84.89 to 88.86%, but increased wet body weight and standard length were found in larvae from TR24 and TR32 groups. Thermal regime during embryogenesis also altered the rate at which the skeletal development occurs. Larvae from the TR32 group showed an advanced skeletal development, with a higher development of cartilaginous structures at hatching but reduced at 16 dpf when compared with the TR24 and TR28 groups. Furthermore, this advanced skeletal development seemed to determine the fish body morphology. Based on biometric measures, a principal component analysis showed how along development, larvae from each thermal regime were clustered together, but with each population remaining clearly separated from each other. The current study shows how changes in temperature may induce craniofacial and morphological alterations in fish during early stages and contribute to understanding the possible effects of global warming in early development of fish and its ecological implications.

Control of thermal regime of thermoelectric coolers in uniform temperature field

The comparative analysis of means of control of a thermal mode at minimization of a complex of the basic parameters in various combinations with indicators of reliability and dynamics of functioning of one-stage thermoelectric cooler is resulted. The study was conducted for the operating range of temperature differences, standard heat load and different geometry of the branches of thermocouples. According to the results of research to minimize the sets of basic parameters in interaction with the indicators of reliability and dynamics of work, a number of current modes of operation have been developed. The developed mathematical models for the optimal operating current from the relative temperature difference and heat transfer of the radiator for the proposed operating modes are analyzed. The results of calculations of the main parameters, reliability indicators, and time of transition to stationary mode of operation for different current modes of operation in the range of temperature differences for different geometry of branches of thermoelements are given. The extremes of dependences of the cooling coefficient, heat dissipation capacity of the radiator, the amount of energy consumed on the relative operating current are determined, which is essential for the implementation of the control function. The possibility of choosing the current mode of operation for optimal control of the thermal regime of single-stage thermoelectric devices manufactured by the same technology, taking into account mass, size, energy, reliability and dynamic characteristics. The developed method of optimal regulation of the thermal regime of a single-stage thermoelectric cooler based on minimizing the set of basic parameters allows finding and choosing compromise solutions taking into account the importance of each of the limiting factors.

Quantification of soil temperature in sole and intercropped pigeonpea (Cajanus cajan L. Millsp.) using meteorological parameters

The meteorological week-wise soil thermal regime in the root zone (5, 15 and 30 cm depth) of pigeonpea and pigeonpea based groundnut (Arachis hypogaea) cropping systems was studied in relation to various meteorological parameters twice a day, 0738 and 1438 hrs (IST) for three years (1986-87, 1987-88 and 1988-89), in the middle Gujarat region. A decline in soil thermal regime was observed on three occasions during the crop growth period viz., at onset of SW monsoon, at the end of rainy season and at the time of harvesting of intercrop, In sole pigeonpea, the soil temperature upto 30 cm depth can be estimated from mean air temperature, whereas in the pigeonpea + groundnut cropping system, before harvest of intercrop the minimum and maximum temperature were found to be more appropriate for estimation of morning and afternoon time respectively, but only in the top layers of the soil.

Reducing energy capacity and increasing the environmental safety of industrial areas when using radiative heating systems based on water infrared radiators

Introduction. It has been repeatedly proven that the use of radiant heating systems leads to an increase in the environmental safety of industrial premises by increasing their energy efficiency. The most promising solution is the use of gas infrared emitters, in which there is no intermediate coolant, and the heat of combustion of the gas enters the room. However, such a solution has a number of limitations on gas availability, comfort and fire hazard. Also, a highly efficient solution is the use of water infrared emitters, which can be represented by emitting panels or emitting profiles that use an intermediate coolant, but do not have many limitations inherent in gas systems. Materials and methods. This study was conducted in the Laboratory of radiant Heating of NNGASU and is devoted to the study of the peculiarities of the formation of the temperature regime in rooms heated by water infrared radiators, as well as the thermal regime of external enclosing structures in these rooms. Results. Based on the results of the experiments, the authors concluded about the formed thermal regime in rooms with heating systems based on water infrared emitters. It is proved that the use of radiant heating leads to a more uniform temperature regime in a heated room, and less overheating of the room covering than when using convective heating systems. Conclusions. The energy efficiency of the use of radiant heating systems based on water infrared emitters has been proven. The study showed that the system of water radiant heating allows to reduce the gradient of air temperature in height not only in large-volume rooms, such as workshops, depots, gyms, but also in rooms with a low height of the coating location. This feature allows you to reduce heat losses through the coating. The temperature regime in the working area of the room with the use of radiant water heating, in comparison with convective, remains unchanged.

Thermal processes in the stack of perishable cargo transported in the heated isothermal car

The article deals with the organization of heat exchange processes when using a new heating system for the cargo room of the isothermal car. Using the example of considering a stack formed from glass containers with fruit juices packed in cardboard boxes, the equivalent thermophysical characteristics of the cargo in the stack are formulated. Analytical methods are used to determine the main regularities of the regular thermal regime and the nature of thermo-gravitational flows in the cargo room of the car. The possibilities of improving the design of the heating system of the cargo room of isothermal rolling stock for the transportation of perishable cargo are considered. The possibilities of modernization of specialized equipment allowing optimization of the temperature regime in the cargo room of the car are presented. The article deals with the organization of heat exchange processes when using a new heating system for the cargo room of the isothermal car. Using the example of considering a stack formed from glass containers with fruit juices packed in cardboard boxes, the equivalent thermophysical characteristics of the cargo in the stack are formulated. Analytical methods are used to determine the main regularities of the regular thermal regime and the nature of thermo-gravitational flows in the cargo room of the car. The possibilities of improving the design of the heating system of the cargo room of isothermal rolling stock for the transportation of perishable cargo are considered. The possibilities of modernization of specialized equipment allowing optimization of the temperature regime in the cargo room of the car are presented.

Development of technological line for obtaining flax trust

One of the most effective ways to intensify heat transfer when blowing surfaces with air is jet blowing. High intensity of transfer processes during jetting, relatively low energy costs for its implementation, simplicity and flexibility of control of this process have led to its widespread use in various fields. Mathematical modeling of heat transfer regularities in systems of impact jets is significantly complicated due to the three-dimensional nature of the flue-channel flow near the surfaces of complex shape. Therefore, it is advisable to use experimental research methods. The purpose of this study is to justify the use of the method of regular thermal regime to determine the average heat transfer coefficient during jet cooling of the surface. Regular mode of cooling (heating) of bodies is characterized by the fact that the relative rate of change of excess temperature for all points of the body remains constant. Since the thermal model was made of a highly thermally conductive duralumin alloy, the condition Bi <0.1 was met, when the average temperatures on the surface and volume will be the same. Therefore, the experiments recorded the readings of only one thermocouple. To compare the results of this experimental study with the results of other authors, cases of blowing a smooth concave surface with single - and three - row jet systems were chosen. The first case was studied in [3,4], the second - in [5]. The results of the performed test experiments agree satisfactorily with the data of these works, which were obtained both by the method of regular mode [5] and other methods of recording heat fluxes ([3] - passive heat flux sensor; [4] - electrocalorimetry). The difference between the average heat transfer coefficients and the known literature data does not exceed ±7..12%, which indicates a sufficient probability of the results obtained in this work, and the possibility of using the method of regular thermal regime in the study of jet cooling of complex bodies. Key words: heat exchange, jet system, cooling, concave surface

Suppressing measurement uncertainty in an inhomogeneous spin star system

The uncertainty principle is known as a foundational element of quantum theory, providing a striking lower bound to quantify our prediction for the measured result of two incompatible observables. In this work, we study the thermal evolution of the entropic uncertainty bound in the presence of quantum memory for an inhomogeneous four-qubit spin-star system that is in the thermal regime. Intriguingly, our results show that the entropic uncertainty bound can be controlled and suppressed by adjusting the inhomogeneity parameter of the system.