Kinematic running resistance of an urban rail vehicle undercarriage: a study of the impact of wheel design.

Urban railway vehicles are important means of transport in towns and cities due to their high capacity, power source, and low running resistance, which make them efficient for operation. Although these properties are considered advantages, there is still room for improvement in their operational efficiency. The main objective of this article is to investigate the impact of railway wheel design on the level of kinematic running resistance, which is expressed as the amount of mechanical energy losses during the interaction of wheels with rails.

Ocean currents break up a tabular iceberg.

In December 2020, giant tabular iceberg A68a (surface area 3900 km) broke up in open ocean much deeper than its keel, indicating that the breakage was not immediately caused by collision with the seafloor. Giant icebergs with lengths exceeding 18.5 km account for most of the calved ice mass from the Antarctic Ice Sheet.

No general stability conditions for marine ice-sheet grounding lines in the presence of feedbacks.

The "marine ice-sheet instability" hypothesis continues to be used to interpret the observed mass loss from the Antarctic and Greenland ice sheets. This hypothesis has been developed for conditions that do not account for feedbacks between ice sheets and environmental conditions. However, snow accumulation and the ice-sheet surface melting depend on the surface temperature, which is a strong function of elevation.

MECHANISMS OF THE FORMATION OF MOTOR-SECRETORY DISORDERS IN PATIENTS WITH GERD WITH CONCOMITANT AIT.

Objective: The aim: The aim of this work was to study the effect of thyroid hormones on motor-secretory dysfunction in patients with GERD with concomitant AIT.

Patients And Methods: Materials and methods: The study involved three groups of patients: with isolated GERD, GERD with AIT at the stage of hypothyroidism and GERD with AIT at the stage of hyperthyroidism. The control group consisted of 15 practically healthy individuals.

Change in future climate due to Antarctic meltwater.

Meltwater from the Antarctic Ice Sheet is projected to cause up to one metre of sea-level rise by 2100 under the highest greenhouse gas concentration trajectory (RCP8.5) considered by the Intergovernmental Panel on Climate Change (IPCC). However, the effects of meltwater from the ice sheets and ice shelves of Antarctica are not included in the widely used CMIP5 climate models, which introduces bias into IPCC climate projections.