Using Ground Penetrating Radar for Permafrost Monitoring from 2015–2017 at CALM Sites in the Pechora River Delta

This paper describes the results of ground penetrating radar (GPR) research combined with geocryological data collected from the Circumpolar Active Layer Monitoring (CALM) testing sites in Kashin and Kumzha in August 2015, 2016, and 2017. The study area was located on the Pechora River delta. Both sites were composed of sandy ground and the permafrost depth at the different sites ranged from 20 cm to 8–9 m. The combination of optimum offset and multifold GPR methods showed promising results in these investigations of sandy permafrost geological profiles. According to direct and indirect observations after the abnormally warm conditions in 2016, the thickness and water content of the active layer in 2017 almost returned to the values in 2015 in the Kashin area. In contrast, the lowering of the permafrost table continued at Kumzha, and lenses of thin frozen rocks that were observed in the thawed layer in August of 2015 and 2017 were absent in 2016. According to recent geocryological and geophysical observations, increasing permafrost degradation might be occurring in the Pechora River delta due to the instability of the thermal state of the permafrost.

Stability Analysis of Soil Flow Protector and Design Method for Estimating Optimal Length

Underground cavities can develop below structures, leading to ground settlement and hindering the development of urban infrastructure. Soil flow protectors (SFPs) have been developed to prevent and alleviate problems due to the formation of such cavities. In this study, we performed scaled model experiments to develop a design method for an SFP with an adequate safety factor under different installation lengths of its upper and lower parts in sandy ground. The installation of the SFP reduced the average surface settlement ratio to the range of 0.44–0.72, thus demonstrating its effectiveness in reducing ground settlement. In addition, we proposed a relational equation for determining the optimal length ratio of the SFP and the settlement ratio. An analysis of the influencing factors showed that the lower part of the SFP influenced the settlement reduction, whereas the upper part influenced the stability of the SFP depending on the ground settlement ratio. Finally, we have proposed an optimal length equation for the SFP and presented a flowchart for the design method. The results of this study can serve as a design basis for the efficient construction of infrastructure.

Critical Design Issues of Heavy Fuel APUs Derived from Automotive Turbochargers. Part 1: Nominal Ambient Conditions

Small, turbine-powered eAPUs (electric Auxiliary Power Unit) have poor off-design performance and efficiency. Turbo eAPUs remain competitive where efficiency is sacrificed to lightness and compactness. The first part of this paper summarizes the transformation of a very efficient, very large automotive turbocharger into an eAPU. A satisfactory solution for the design of the heavy fuel combustor has been found on the Giandomenico’s site. The performance of the APU is evaluated at the Garrett nominal air conditions (T0=302.6 K, p0=0.962 bar, dry air). The turbogas has an approximately linear braking torque from 50% to 100% load at nearly maximum efficiency. Below 50% load, it is more convenient to vary the maximum temperature of the cycle and adjust the generator torque. However, a better compromise can be obtained by coupling the APU with a battery that would supply the electric power under 50% load. The use of a recuperator is not convenient due to the increase in volume and the additional complication. The problem of the intake air filtering is particularly serious in dirty/sandy ground applications. Regarding efficiency, the turbogas is no match for the diesel eAPUs.

External training load and the effects on training response following three different training sessions in young elite beach volleyball players

Purpose The interaction between external training load (ETL) and players internal response in beach volleyball is currently poor investigated. Using single parameters (e.g. jump volume) described in indoor settings is questionable due to specific load characteristics like sandy ground and reduced number of players. The aim of this work is to analyze ETL and the effects on training response in different beach volleyball training settings. Methods This study was conducted with 7 youth elite athletes (age: 18.9 ± 1.3 years, height: 185.2 ± 7 cm, body mass: 75.9 ± 10.4 kg, 2 males/5 females). Training sessions were classified into three categories with (A) high session jump volume (SJV) and lower proportions of other action types like diving, reception, defense actions and setting, (B) moderate SJV and (C) low SJV and higher proportions of other action types. Delayed Onset of Muscle Soreness [DOMS], Creatinkinase [CK] and session rate of perceived exertion [s-RPE] were analyzed as training response markers. Results Mean pre to post differences in CMJ-Height were highest at sessions with high jump volume and less other actions (Session A) with no significant differences between (C) to (B) ( p = .128), (C) to (A) ( p = .237) and (B) to (A) ( p = .101). Response markers (DOMS, s-RPE, CK) showed increased values at session type C. Conclusions SJV does not seem to trigger training response with higher marker responsiveness during low frequency sessions. Changes in directions, diving or fast getting up might rather provoke fatigue during training.