Исследование процесса теплообмена при охлаждении форели с применением диоксида углерода

Using data from the Infrared Array Camera on the Spitzer Space Telescope, we present photometric observations of a sample of 100 trans-Neptunian objects (TNOs) beyond 2.2 μm. These observations, collected with two broadband filters centered at 3.6 and 4.5 μm, were done in order to study the surface composition of TNOs, which are too faint to obtain spectroscopic measurements. With this aim, we have developed a method for the identification of different materials that are found on the surfaces of TNOs. In our sample, we detected objects with colors that are consistent with the presence of small amounts of water, and we were able to distinguish between surfaces that are predominantly composed of complex organics and amorphous silicates. We found that 86% of our sample have characteristics that are consistent with a certain amount of water ice, and the most common composition (73% of the objects) is a mixture of water ice, amorphous silicates, and complex organics. Twenty-three percent of our sample may include other ices, such as carbon monoxide, carbon dioxide, methane, or methanol. Additionally, only small objects seem to have surfaces dominated by silicates. This method is a unique tool for the identification of complex organics and to obtain the surface composition of extremely faint objects. Furthermore, this method will be beneficial when using the James Webb Space Telescope for differentiating groups within the trans-Neptunian population.

Some of Iranian oil reservoirs suffer from operational problems due to asphaltene precipitation during natural depletion, so widely investigation on asphaltene precipitation is necessary for these reservoirs. In this study, a reservoir that is candidate for CO2 gas injection process is selected to investigate asphaltene precipitation with and without CO2 injection. In this case, asphaltene precipitation is monitored at various pressures and reservoir temperature. Then, a series of experiments are carried out to evaluate the amount of precipitated asphaltene by injection different molar concentrations (25%, 50%, and 75%) of CO2. The results show that during primary depletion the amount of precipitated asphaltene increases with pressure reduction until bubble point pressure. Below the bubble point the process is reversed (i.e., the amount of precipitated asphaltene at bubble point pressure is maximum). The behavior of asphaltene precipitation versus pressure for different concentrations of CO2 is similar to primary depletion. Asphaltene precipitation increases with CO2 concentration at each pressure step. In the modeling part, solid model and Peng-Robinson equation of state are employed which show a good match with experimental results.

For the first time in the laboratory, the effectiveness of protection of the MARZA-1 inhibitor from corrosion in aggressive environments with hydrogen sulfide, carbon dioxide and carbon dioxide in combination with hydrogen sulfide was investigated. Laboratory tests were carried out in a solution of an analogue of formation water MI. The experiments were carried out for one and ten days at an inhibitor concentration of 3.0, 5.0, 7.0, 10.0 mg/l. The results of numerous laboratory studies have shown that in all cases the protective effect of the MARZA-1 inhibitor increases with an increase in its concentration. The greatest effect was recorded at 10 mg/l for 24 and 240 hours. This effect was 98.0 and 95.7% in a hydrogen sulfide environment, 94.80 and 94.83% in a carbon dioxide environment, 96.8 and 99.23% in a mixed environment (H2S + CO2). Keywords: hydrogen sulfide, carbon dioxide, inhibitor, MARZA-1, corrosion, protective effect, gravimetric method

BACKGROUND: The selection of refrigerants for modern air conditioning systems (ACS) in ground facilities is a multidisciplinary task. Particularly, meeting the required energy efficiency of the refrigeration cycle as well as ensuring ecological safety of production, operation, and utilization of the refrigeration system. Herein, the working pressure levels of the refrigeration cycle considerably affect the availability, cost, and safety of the refrigeration equipment. The fire safety of the working substance is also important.
 AIM: To investigate the feasibility of a mixture of dimethyl ether and carbon dioxide as refrigerant for energy efficient and safe application of ACS in ground facilities.
 METHODS: Comparative analysis of a simple one-stage vapor–compression cycle using traditional working substances (R22 and R410A) and the proposed working substance, which is in the form of a mixture of dimethyl ether and carbon dioxide, using packages, such as Mathcad, HYSYS, CoolPack, and REFPROP, was performed.
 Results: An ecofriendly mixture of dimethyl ether and carbon dioxide with low global warming potential and zero ozone depletion potential was proposed as refrigerant. Increasing the percentage of dimethyl ether in the blend reduces the temperature glide in the gas cooler, a property of CO2, and pressures at which the blend operates. The mixture has limited operational properties due to the flammability of dimethyl ether, but its environmental performance makes the material of some practical interest.
 CONCLUSION: Fire safety of the proposed working substance was calculated. The concentration of dimethyl ether in the mixture at which it becomes flammable and unsafe for ACS was determined to be 8.3%.
 With an increase in the dimethyl ether content in the mixture with CO2 from 4% to 8%, the refrigeration coefficient of the cycle increases from 2.53 to 2.88, but it is 1.57 times less than that of R410A.
 The difference in operating pressures between the used non-ecological refrigerants and proposed mixture was determined. Results indicate that the mixture of dimethyl ether and carbon dioxide is currently inapplicable to mass production compressors, which use R410A as refrigerant. The condensation pressure of the most effective and nonflammable mixture of dimethyl ether and CO2 (with dimethyl ether concentration of 8%) is 101 bar against 30 bar for R410A.
 Therefore, we intend to evaluate test mixtures of dimethyl ether with other substances in the future.

Electroless undoped and Co, Al co-doped ZnO (Zn1 − x − yCoxAlyO: x = 0.04, 0.03, 0.02; y = 0.01, 0.02, 0.03) nanostructured thin films were deposited on soda lime glass in the present work. Microstructure of the ZnO films was strongly influenced by different doping concentrations of Co and Al into ZnO matrix. X-ray diffraction analysis has confirmed the absence of metallic Co or Al clusters apart from wurtzite type ZnO. The field dependence of magnetisation (M–H) curve of different concentration of Co and Al co-doped ZnO films was measured at room temperature. The ferromagnetism with saturation magnetisation (Ms) and coercive field (Hc) of the order of 3.843–4.813 × 10− 3 (emu) and 400.389–436.769 (Oe) respectively were observed for the doped ZnO thin films. The mechanisms for the ferromagnetism at room temperature in Co and Al co-doped ZnO films are discussed.

Studies were conducted in Zimbabwe of the catch of Glossina pallidipes Austen from an electric net plus target baited with mixtures of acetone plus carbon dioxide or 1‐octen‐3‐ol (octenol) plus carbon dioxide. For acetone dispensed alone at 5–50, 000 mg h‐1, ten‐fold increments in the dose increased the catch 1.7 times. For carbon dioxide dispensed alone, dose increments from 12 to 1201 h‐1 doubled the catch, but the catch was not further increased by dispensing carbon dioxide at 600–1200 1 h‐1. For mixtures of these two odours, ten‐fold increments in the dose of carbon dioxide between 12 and 12, 0001 h‐1 increased the catch c. 2.5 times if acetone was also dispensed at >50 mg h‐1; changes in the dose of acetone between 50 and 50 000 mg h‐1 did not affect the catch. The addition of octenol (0.05 mg h‐1) to carbon dioxide (12–12001 h‐1) doubled the catch. Ten‐fold increments in the dose of octenol between 0.05 and 5 mg h‐1 did not increase the catch significantly and the catch was independent of changes in the dose of carbon dioxide between 120 and 12001 h‐1. The behavioural basis of the dose‐response curves was investigated using an incomplete ring of electric nets to assess the flight orientation of tsetse in different odours. Upwind flight was not elicited by acetone or octenol alone, or by carbon dioxide unless it was at very high doses, however, mixtures of carbon dioxide with acetone or octenol elicited upwind flight. It is suggested that the attractiveness of mixtures of acetone and carbon dioxide is a function of the region of overlap of these two odours at above threshold concentration. Acetone and octenol on their own appear to increase the responsiveness of flies to visual cues.

Combining carbon dioxide and strong emulsifier in-depth huff and puff with DCA microsphere plugging in horizontal wells of high-temperature and high-salinity reservoirs

A behavioral bioassay was developed to test responses of newly hatched (neonate) larvae of western corn root worm Diabrotica virgifera virgifera LeConte to volatile compounds from corn plants, a major host for this insect. A glass Y -tube filled with glass beads was used to allow choice tests in a vertical direction and to reproduce the thigmotactic cues available to larvae in their natural soil environment. A syringe pump was used to provide slow, consistent delivery of candidate compounds to the 2 sides of the apparatus. Significantly more larvae were attracted to the side containing a germinating corn seed than to the side containing ambient air. In addition, significantly more larvae were attracted to the side containing cut corn roots than to the side containing an ambient air control. Carbon dioxide (CO2) from corn roots previously has been implicated as an attractant for the larvae, and dose-response curves for larval attraction to Co2 were obtained using different sources (different dilutions of carbonated water, the head space over a carbonated water dilution, and different concentrations of CO2 in air). The CO2 concentrations for all sources were measured by mass spectrometry with selected ion monitoring at m/e 44.Neonate larvae were significantly attracted to concentrations of CO2 as low as 1.125 ± 0.04mmol/mol (concentration of CO2 in ambient air on the control side was 0.99 ± 0.02 mmol/mol). Larvae were optimally attracted to 2.51-4.20 mmol/mol CO2, but they were attracted to concentrations as high as 100 mmol/mol. Larvae were not attracted to 300 or 900 mmol/mol CO2, and they exhibited toxic symptoms at these high concentrations. The concentration of CO2 in soil near growing com roots was 4.36 ± 0.31 mmol/mol, which was consistent with the behavioral optimum for the larvae. The concentration of CO2 in soil that contained no corn was 1.38 ± 0.03 mmol/mol and the concentration in ambient air was 0.94 ± 0.01 mmol/mol.

The inventory of water and carbon dioxide reservoirs on Mars are important clues for understanding the geological, climatic and potentially exobiological evolution of the planet. From the early mapping observation of the permanent ice caps on the martian poles, the northern cap was believed to be mainly composed of water ice, whereas the southern cap was thought to be constituted of carbon dioxide ice. However, recent missions (NASA missions Mars Global Surveyor and Odyssey) have revealed surface structures, altimetry profiles, underlying buried hydrogen, and temperatures of the south polar regions that are thermodynamically consistent with a mixture of surface water ice and carbon dioxide. Here we present the first direct identification and mapping of both carbon dioxide and water ice in the martian high southern latitudes, at a resolution of 2 km, during the local summer, when the extent of the polar ice is at its minimum. We observe that this south polar cap contains perennial water ice in extended areas: as a small admixture to carbon dioxide in the bright regions; associated with dust, without carbon dioxide, at the edges of this bright cap; and, unexpectedly, in large areas tens of kilometres away from the bright cap.

In Brazil, there are few studies on cut flowers cold storage, and there is no research on the association of controlled atmosphere with flower cooling. Worldwide research in this sector is considered scarce; this requires the establishment of adequate postharvest technology, involving cold storage and controlled/modified atmosphere for cutting flowers. In Brazil, roses are the most widely cultivated cut flower and a single producer exports three pallets of this species by airfreight per week. The objectives of this work were to define the concentrations of O2 and CO2 in which cut roses ‘Avalanche’ should be submitted, defining procedures for postharvest conservation and establishing technical guidelines for the exportation of cut roses under controlled atmosphere. The experiments were carried out at 1±1 °C with the help of a flowchart to dose the gases, and the concentration of O2 , CO2 and ethylene were assessed. Phase 1 experiment had O2 concentration set at 21% associated with four different concentrations of CO2 , 10, 20, 30 and 40%. Phase 2 experiment had O2 at 3% associated with four different concentrations of CO2 , 3, 6, 10 and 15%. The controlled atmosphere with 3% O2 and 6% CO2 associated with 1+1 °C was indicated for the storage of cut rose ‘Avalanche’.

Saturn's moon Hyperion, an irregular shaped object in a tumbling orbit, looks odd: the Cassini flyby of September 2005 revealed a unique spongy surface. Two papers this week present the initial Cassini results. First, imaging and radio data suggest that the spongy appearance is caused by impact cratering on a porous body. And second, near-infrared and ultraviolet spectroscopy reveal details of the surface composition of the highly reflective areas that cover much of the surface, and also of the darker areas, mostly at the bottom of craters. The spectra are consistent with the presence of water ice contaminated with an organic solid. The low-albedo (dark) material is spectroscopically similar to that found on two other saturnian moons, Iapetus and Phoebe, containing a mixture of water ice, complex organics, carbon dioxide and nitriles. This cocktail of materials resembles those seen in comets and probably in Kuiper Belt objects.

The extraction of methane from its hydrates using carbon dioxide involves the decomposition of the hydrate resulting in a CH4-CO2-H2O ternary solution. Using classical molecular dynamics simulations, we investigate the evolution of dissolved gas molecules in the ternary system at different concentrations of CO2. Various compositions considered in the present study resemble the solution formed during the decomposition of methane hydrates at the initial stages of the extraction process. We find that the presence of CO2 aids the formation of CH4 bubbles by causing its early nucleation. Elucidation of the composition of the bubble revealed that in ternary solutions with high concentration of CO2, mixed gas bubbles composed of CO2 and CH4 are formed. To understand the role of CO2 in the nucleation of CH4 bubbles, the structure of the bubble formed was analyzed, which revealed that there is an accumulation of CO2 at the interface of the bubble and the surrounding water. The aggregation of CO2 at the bubble-water interface occurs predominantly when the concentration of CO2 is high. Radial distribution function for the CH4-CO2 pair indicates that there is an increasingly favorable direct contact between dissolved CH4 and CO2 molecules in the bubble-water interface. It is also observed that the presence of CO2 at the interface results in the decrease in surface tension. Thus, CO2 leads to greater stability of the bubble-water interface thereby bringing down the critical size of the bubble nuclei. The results suggest that a rise in concentration of CO2 helps in the removal of dissolved CH4 thereby preventing the accumulation of methane in the liquid phase. Thus, the presence of CO2 is predicted to assist the decomposition of methane hydrates in the initial stages of the replacement process.

The unicellular green alga Monoraphidium minutum and the diatom Nitzschia perminuta were cultured under different concentrations of Co2+. Growth and pigment content were slightly increased at low concentrations and inhibited by high Co2+ concentrations. The results concerning the effect of different concentrations of Co2+ on photosynthetic O2 evolution showed a reduction in the amount of O2 evolved by each alga in response to increasing Co2+ concentrations. However, an increase in O2 evolution for both M. minutum and N. perminuta was observed at relatively low Co2+ concentrations. Photosynthetic electron transport in M. minutum was more sensitive to Co2+ toxicity than in N. perminuta. On the other hand, the effect of the heavy metal on respiration showed that higher Co2+ concentrations were inhibitory to O2 uptake by the two algal species. Low Co2+ concentrations stimulated O2 uptake by M. minutum throughout the experimental period. However, in N. perminuta, different concentrations of Co2+ led to a reduction of O2 uptake. To localize the action site of Co2+ in the photosynthetic electron transport chain, the fluorescence induction technique was carried out. According to the results obtained, the inhibitory action of Co2+ is located on the acceptor side of PSII for both M. minutum and N. perminuta.

Apart from other pollutants, flaring of natural gas adds carbon dioxide into the environment and changes the atmospheric composition, including temperature and humidity. As a major gaseous product, carbon dioxide changes plant structural components as well as herbivores, i.e., insect by dilution of nitrogen under such circumstances. Present analysis demonstrated the impact of gas flaring upon adjoining biota especially Eurema hecabe butterfly and its host plant, Cassia tora in some wells (group gathering stations) of Assam, India. Analysis, pertaining from the current investigation, documented higher carbon dioxide as well as temperature in the studied flaring sites. Apart from this, reduction of leaf nitrogen, SLA, and chlorophyll with increasing in LDMC, thickness, and carbon in the studied plant as well as poor developmental rate, RGR, ECD with high RCR in insect indicated severe impact of flaring in those areas. Simulation studies with different concentration of CO2 in open top chamber on the plant and butterfly also revealed similar trend of results.

The effects of hypercapnia and hypoxia on the regulation of breathing was studied in six mongrel dogs during pentobarbital anaesthesia with special reference to their action on the respiratory muscles. Carbon dioxide (5.5% in air) inhalation produced an increase of minute volume due to augmentation of respiratory frequency and tidal volume. The number of electrical impulses per breath remained unaffected despite the increase tidal volume. Therefore the mechanical ventilation increased more than the electrical output to the respiratory muscles indicating that the efficiency of the muscles increased. The tidal volume increased more than the pressure impulse (mechanical work by the respiratory muscles) suggesting that the airway conductance was increased during hypercapnia. During hypoxic stimulus (11% oxygen in nitrogen) the increase of minute volume was due to increase in respiratory frequency. The ratio of tidal volume to the number of electrical impulses in the respiratory muscles remained unaltered. During combined carbon dioxide and hypoxia stimulus the responses were similar to those of carbon dioxide stimulus alone. However, the increase of minute volume and the increase in the ratio of tidal volume and pressure impulse to the number of electrical impulses in the respiratory muscles were more pronounced. These findings suggest that carbon dioxide affects the regulation of breathing above the respiratory muscles and in the muscles themselves. Hypoxic stimulus seems not to have any direct effect on the respiratory muscles in dogs during pentobarbital anaesthesia.