Drying Machines with Combined Hydrodynamic Regimes

The article is devoted to the study of multistage dryers with vertical sectioning of the working space. The factors of influence of the design of the shelf contact and the consumption of the drying agent on the mode of movement of monodisperse and polydisperse material are analyzed. The achievement of the required hydrodynamic regime (at a constant consumption of the drying agent) was ensured by changing the length of the shelf contact, the angle of its inclination to the horizon, and the degree of perforation (free area of cross-section). The features of changing the mode of granular material movement at various stages of the gravitational shelf dryer are shown. A technique for the optimization calculation of a gravitational shelf dryer is proposed. As an objective function, the minimum residence time of the dispersed material in the dryer is taken, at which the required amount of moisture is removed. Variants of the designs of the stages of a gravitational shelf dryer are shown and the features of the movement of dispersed material on the steps are described. The results obtained can be used as the basis for the engineering design of gravitational shelf dryers.

Modeling of cooling process of hydroaluminosilicate materials

Porous thermal-insulation materials are widely used in building industry, the advantages of which are cheapness and efficiency. Their commercial appearance is also important in their implementation. Porous thermal-insulation materials to prevent sticking can be packaged only after cooling and after the main thermal processes and classification. The process of cooling porous hydroaluminosilicate materials by the method of modeling with the subsequent check on the laboratory equipment with a fluidized bed is investigated in the work. The main thermal process takes place at a temperature of about 300°C. The cooling time of the porous material to a temperature of 20°C, which is about 20 seconds, is calculated, and the need to ensure this time in its classification is indicated. This model allows you to determine with sufficient accuracy the cooling time for particles of different diameters and temperatures. The process of cooling the obtained thermal insulation material in the production technology occurs simultaneously with its hydrodynamic classification in the cascade classifier of the fluidized bed. It is important to determine the required cooling time of the spherical hydroaluminosilicate material to temperatures close to 20°C and to ensure the presence of particles in the apparatus during this time. Comparison of experimental data with the results of the mathematical model shows the results with an error of 10%. There is a slight increase in the minimum residence time of a single granule obtained experimentally compared with the calculated.

Experimental and Numerical Modeling the Effect of the Residual Stress in the Case of the Molding of a Plastic Part

There is always time and energy optimization and reduction of faults the aim of research and in this context our article presents a study of a practical case of the deformation of a plastic part placed in a refrigerator for food storage, and that the use increases in number of these types of metals, are found in several sectors, and because of their industrial performance, a minimum residence time of the part in the mold is sought in order to reduce the cycle time of the process at the same time that the injection process is quite complex and requires a certain number of recurring questions to succeed. In the desired model. These are linked to residual stresses and deformations, pressure, mold temperature, filling threshold, shape of the part, but also to other mechanical and optical properties. Several investigations have been carried out and according to the authors the causes of these failures vary according to the manufacturing technique used. In this article, we try to find the origin of a deformation detected on a part at the end of the mold. Our work consists first of all in presenting, according to different studies, the thermomechanical properties of the material injected at different stages of the injection process. In a second step, compare the theoretical and analytical results. At the end of our study, we propose an optimization of the parameters necessary for the success of the molding and of the geometry of the assembly (mold and part).

Decomposition of dinosaurian remains inferred by invertebrate traces on vertebrate bone reveal new insights into Late Jurassic ecology, decay, and climate in western Colorado

A survey of 2,368 vertebrate fossils from the Upper Jurassic Mygatt-Moore Quarry (MMQ) (Morrison Formation, Brushy Basin Member) in western Colorado revealed 2,161 bone surface modifications on 884 specimens. This is the largest, site-wide bone surface modification survey of any Jurassic locality. Traces made by invertebrate actors were common in the assemblage, second in observed frequency after vertebrate bite marks. Invertebrate traces are found on 16.174% of the total surveyed material and comprise 20.148% of all identified traces. Six distinct invertebrate trace types were identified, including pits and furrows, rosettes, two types of bioglyph scrapes, bore holes and chambers. A minimum of four trace makers are indicated by the types, sizes and morphologies of the traces. Potential trace makers are inferred to be dermestid or clerid beetles, gastropods, an unknown necrophagous insect, and an unknown osteophagus insect. Of these, only gastropods are preserved at the site as body fossils. The remaining potential trace makers are part of the hidden paleodiversity from the North American Late Jurassic Period, revealed only through this ichnologic and taphonomic analysis. Site taphonomy suggests variable, but generally slow burial rates that range from months up to 6 years, while invertebrate traces on exposed elements indicate a minimum residence time of five months for carcasses with even few preserved invertebrate traces. These traces provide insight into the paleoecology, paleoclimate, and site formation of the MMQ, especially with regards to residence times of the skeletal remains on the paleolandscape. Comprehensive taphonomic studies, like this survey, are useful in exploring patterns of paleoecology and site formation, but they are also rare in Mesozoic assemblages. Additional work is required to determine if 16.174% is typical of bulk-collected fossils from Jurassic ecosystems in North America, or if the MMQ represents an unusual locality.

Modelling of optimum cascade of ideal mixing reactors

It is discussed the using of dynamic programming method to optimize the parameters of the cascade of ideal mixing reactors, which is held isothermal first order reaction. It is found, that the minimum volume of the cascade of reactors corresponds to the minimum residence time of substance in this cascade. The optimum value of residence time for all reactors are equal and all ratio of input and output concentrations are equal, hence, and all volumes of reactors are also equal. A total volume of the cascade of reactors is less than the amount single. Application of the method of dynamic programming is illustrated with an example of the calculation of the polymerization in a cascade of four reactors according to the literature experimental data.

Efficacy of pharmacokinetic interactions between piperonyl butoxide and albendazole against gastrointestinal nematodiasis in goats

To test the hypothesis that modulation of hepatic microsomal sulphoxidation and sulphonation by the cytochrome P450 inhibitor piperonyl butoxide could increase bioavailability of albendazole, the present study was undertaken to understand the pharmacokinetics of albendazole in goats at a dose of 7.5 mg kg− 1 body weight with and without co-administration with piperonyl butoxide at 63.0 mg kg− 1 body weight. Plasma albendazole sulphoxide metabolite, the anthelmintically active moiety, reached its maximum concentration of 0.322 ± 0.045 μg ml− 1 and 0.384 ± 0.013 μg ml− 1 at 18 h and 24 h after administration of albendazole alone and co-administration of albendazole with piperonyl butoxide, respectively. Analysis of the data revealed statistically increased albendazole sulphoxide levels at 24 (P < 0.001), 30 (P < 0.001) and 36 h (P < 0.01) after administration of albendazole with piperonyl butoxide, with statistically increased levels of albendazole sulphone at 24, 30 and 48 h after administration. No significance difference (P > 0.05) in values of maximum concentration (normal and calculated) could be observed between groups of goats. However, values of time to reach the concentration maximum (normal and calculated), area under the concentration–time curve (0–∞ and calculated), minimum residence time, distribution half-life, elimination half-life and total area under the first movement of plasma drug concentration–time curve were significantly higher (P < 0.05) in plasma levels of albendazole sulphoxide in goats following single oral co-administration of albendazole with piperonyl butoxide. The faecal egg count reduction and lower 95% confidence limit for the group treated with albendazole alone were 97 and 68%, while for co-administration of albendazole and piperonyl butoxide the values were 99 and 97%, respectively. The ED50 for egg hatch was 0.196, indicating suspected resistance to benzimidazole anthelmintics. The drug combination proved efficacious against an albendazole-resistant nematode parasite population in goats.

Ascension Island as a mid-Atlantic developmental habitat for juvenile hawksbill turtles

Ascension Island in the South Atlantic Ocean is renowned for its globally-important nesting population of green turtles (Chelonia mydas) that has been the subject of long-term research. By comparison, very little is known about the apparently small population of hawksbill turtles (Eretmochelys imbricata) that have been recorded in its waters, thousands of kilometres from known nesting beaches. Here, we collate 10 years of in-water tagging data, opportunistic public sighting records and underwater observations to provide a baseline for future research, and present preliminary data on habitat use derived from two individuals fitted with GPS transmitters. Although public sightings were inevitably biased towards popular recreation areas, the resulting distribution suggests that hawksbill turtles occur year round in Ascension Island's waters along the entire 65 km of coastline. Hawksbills were observed feeding on benthic algae and encrusting sponges, and were frequently seen scavenging on fish discards around the Island's pier at night aided by anthropogenic lighting. Between 2003 and 2013, 35 turtles were captured, measured, tagged and then released. Curved carapace lengths ranged from 33.5 to 85 cm (mean = 48.8 cm) indicating that most (if not all) individuals encountered around Ascension are post-pelagic juveniles. Four individuals were recaptured at least once giving a mean minimum residence time of 4.2 yr (range: 2.8–7.3 yr) and a mean growth rate of 2.8 cm yr−1. Turtles fitted with Fastloc™ GPS devices remained at Ascension Island for the duration of the study (>90 days) and occupied restricted home ranges with an average area of 2.5 km2 and an average ‘core use area’ (50% utilization distribution) of 0.05 km2. Together, these results suggest that Ascension Island serves as a mid-Atlantic developmental habitat for benthic-feeding, juvenile hawksbill turtles on extended oceanic migrations before recruiting to their adult foraging grounds, likely to be located in Brazil or tropical West Africa.

Diffuser Influence on the Mixing of Coaxial Swirling Jets

Numerical results depicting the effects of diffusers on confined isothermal high-swirl jets are presented. The aim is analyze the mixing between a non-swirling inner jet (natural gas) and a swirling annular jet (primary air). This simple setup is widely used in burners to promote stabilized flames of lean mixtures. Flow patterns for sudden-expansion and diffusers are contrasted for swirl number of 1 and expansion area ratio of 4 in a transitional turbulence regime. Diffusers have important influence on size and location of recirculation zones. Hence knowledge of flow characteristics is a prerequisite in the design process. The criteria to establish the optimum diffuser would be better mixing as well as minimum residence time in the recirculation zones to prevent the formation of NOx in the future burner. The dissipated mechanical energy is not important in burner applications.