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The Hyperloop system offers revolutionary transportation, aiming for near-sonic speeds in a low-pressure environment. The aerodynamic design challenges of multiple vehicles in a confined tube remain largely unexplored, particularly regarding vehicle spacing and suspension gaps. This study investigates a jet-propelled, multi-vehicle Hyperloop system using Reynolds-Averaged Navier–Stokes (RANS) equations and the k − ω turbulence model. Analysis of suspension gaps and vehicle spacing on drag and thrust revealed that suspension gaps cause significant jet deflection, reducing effective thrust and increasing drag. It was found that vehicle suspension, with a 75 mm suspension gap, increased drag by 58% at Mach 0.7 compared to the unsuspended configuration. Meanwhile, smaller vehicle spacing ( X v = 0.25 L v ) reduced the drag by up to 50%, enhancing system efficiency. The results emphasize the need to address the effect of jet deflection and optimize vehicle spacing for maximum energy savings. These findings offer valuable insights for enhancing aerodynamic performance in multi-vehicle Hyperloop systems. [ABSTRACT FROM AUTHOR]

By means of determining the suspension effect, the authors studied the change in the surface properties of apatite under the action of reagents and ions present in flotation pulp during processing of apatite-bearing ore. It is shown that the ratio of acid–base centers of apatite surface change in interaction with ions HCO , CO , HPO , cations Ca and oleate ions in distilled water and in water after deionization to remove carbon dioxide. The change in apatite surface properties in alkaline water shows up as quantitative superiority of base centers. Such ionization of mineral surface favors adsorption of cations, for example, Ca , and sets background for more efficient interaction between anion-type agents. The data obtained from the studies of the suspension effect, correlate with the results of infrared spectroscopy of apatite treated by the appropriate agents. [ABSTRACT FROM AUTHOR]

The results reflecting influence of thermal treatment of basalt tufa (BT) on its phase composition and capacity of some heavy metal ions (Cu2+, Mn2+, Ni2+, Pb2+, Zn2+) sorption under the static conditions are presented. It has been found that thermal modification of tufa at 400–1000 0С results in weight loss of the material from 5,79 % (at 400 0C) to 10,18 % (1000 0C) caused by changes in the mineral phase composition such as loss of the chemically bound water, decomposition of carbonates and other compounds. It has been shown that the sorption value for the heavy metal ions, being captured on surface of the thermally modified BT samples, is governed by the ion’s nature and temperature of its thermal treatment. The negatively charged surface-active adsorption centers were identified for all BT samples since they exhibited the positive suspension effect. Therefore, a competition between adsorption of H+ and heavy metal ions can take place.

Two short-term summer cruises were performed in the vicinity of Rizhao Port, western Yellow Sea, to investigate summer water stratification and the phenomenon of marine sediment acidification. Results show that water stratification has formed as early as in May. The chemoclines of dissolved oxygen (DO) and pH usually occur deeper than the thermocline. Sometimes the chemoclines of DO and pH occur synchronously at the same depths, but sometimes they do not synchronize. Above the chemocline DO fluctuates markedly and maintains at a high level or even oversaturation in daytime, suggesting the far-field impact of vessel propulsion. Below the chemocline it invariably remains at a low and stable level and slowly drops downward. The pH values of surface sediments vary in the range of 6.3–7.6. A conspicuous sediment acidification is observed along the navigation region. This phenomenon is chiefly attributed to the intermittent disruption of summer stratification by shipping activity along the shipping channel and waterways. Water stratification precludes the penetration of DO down to the bottom sediments on fair ocean status, and maintains anoxia below the sediment–water interface, whereas the abrupt DO increase driven by propeller agitating is nearly restricted in the navigation area. Therefore, the aeration effect accelerating oxidation of reducing substances and organic matter is primarily responsible for enhanced acid accumulation in surface sediments. In addition, the suspension effect is identified by the negative offsets of zero point on pH–mV diagram. Most of the measured points are scattered correspondingly on three distinct regression lines, with similar slopes but different negative offsets of pH 6.53, 6.87, and 6.99, respectively. Their geographical distribution suggests that this effect has a positive relationship with the intensity of anthropogenic disturbance. Although the suspension effect is caused by the adsorption of charged particles at the pH glass electrode interface (Yang et al. in Part Sci Technol 7:139–152, 1989), its various intensity observed in practice may also reflect the inherent distinction of depositional environments in physicochemical conditions. [ABSTRACT FROM AUTHOR]

The results reflecting influence of thermal treatment of basalt tufa (BT) on its phase composition and capacity of some heavy metal ions (Cu2+, Mn2+, Ni2+, Pb2+, Zn2+) sorption under the static conditions are presented. It has been found that thermal modification of tufa at 400-1000 °C results in weight loss of the material from 5,79 % (at 400 °C) to 10,18 % (1000 °C) caused by changes in the mineral phase composition such as loss of the chemically bound water, decomposition of carbonates and other compounds. It has been shown that the sorption value for the heavy metal ions, being captured on surface of the thermally modified BT samples, is governed by the ion's nature and temperature of its thermal treatment. The negatively charged surface-active adsorption centers were identified for all BT samples since they exhibited the positive suspension effect. Therefore, a competition between adsorption of H+ and heavy metal ions can take place. [ABSTRACT FROM AUTHOR]

There are marked differences in the pH values determined in water suspension under laboratory conditions and in soil solution under field conditions in hydromorphic soils (gleysols and stagnosols). The value δpH = pH-pH can be either positive or negative. Among the main factors that affect the value of δpH are the laboratory preparation of soil samples and the suspension effect. The sign of the pH effect (value of δpH) depends on the participation of humus, carbonate, and exchange bases in the formation of aggregates destructed in the laboratory. The value of δpH is negative in noncalcareous soils with low content of exchangeable bases and fulvate composition of humus and positive in calcareous soils or soils enriched with exchangeable bases and humate composition of humus. In cases of a significant δpH effect, the value of pH cannot be regarded as an adequate measure of soil acidity. [ABSTRACT FROM AUTHOR]

After recognition of the Suspension Effect problem in potentiometric measurements in aqueous suspensions, no scientific consensus about its cause and nature was obtained. Numerous conventional methods of soil pH measurement were therefore introduced for practical soil pH determination. Most of the results of these methods are not valid with regard to the international pH scale. The method proposed in the present work rejects improper procedures and introduces correct soil sampling and a suitable pH measuring technique, as follows: the indicator glass electrode, substituting for roots in the soil, is inserted in a partly diluted sample suspension of the original soil and the modified reference electrode contacts the sample in a manner that eliminates the abnormal liquid junction potential. „Actual soil pH values“ measured in this way are valid but the method used is a conventional one. Namely, the irreversible potential of the glass electrode includes the suspension effect of the first kind (SE1) and is a mixed steady-state potential. It is considered by convention as a substitute for and equivalent to the equilibrium potential which as a rule does not exist in a suspension. The soil pH values measured by the proposed conventional method are reproducible and valid with regard to the international hpH scale. They could be considered as the pH values, with uncertainty of +/- 0.1 pH unit, to which the roots are exposed. [ABSTRACT FROM AUTHOR]