Normalised Root Mean Square and Amplitude of Sidebands of Vibration Response as Tools for Gearbox Diagnosis

Quick assessment of the condition of gearboxes used in helicopters is a safety requirement. One of the most widely used helicopter on-board-mounted condition monitoring system these days is the Health and Usage Monitoring System. It has been specifically designed to monitor the condition of all safety-critical components operating in the helicopter through calculation of so-called condition indicators (CIs) - signal processing routines designed to output a single number that represents the condition of the monitored component. Among number of available parameters, there is a couple of CIs that over the years of testing have earned a reputation of being the most reliable measures of the gear tooth condition. At the same time, however, it has been observed that in some cases, those techniques do not properly indicate the deteriorating condition with the propagation of a gear tooth fault with the period of operation. Hence, three more robust methods have been suggested, which are discussed in this article

Kankakee Dam Discharge Characteristics

published or submitted for publicationis peer reviewedOpe

Dynamics of ions in the selectivity filter of the KcsA channel

The statistical and dynamical properties of ions in the selectivity filter of the KcsA ion channel are considered on the basis of molecular dynamics (MD) simulations of the KcsA protein embedded in a lipid membrane surrounded by an ionic solution. A new approach to the derivation of a Brownian dynamics (BD) model of ion permeation through the filter is discussed, based on unbiased MD simulations. It is shown that depending on additional assumptions, ion’s dynamics can be described either by under-damped Langevin equation with constant damping and white noise or by Langevin equation with a fractional memory kernel. A comparison of the potential of the mean force derived from unbiased MD simulations with the potential produced by the umbrella sampling method demonstrates significant differences in these potentials. The origin of these differences is an open question that requires further clarifications

Sediment Loads of Illinois Streams and Rivers

Many river projects require knowledge of the sediment load transported by the river. Suspended sediment load data for 63 locations on Illinois streams and lake sedimentation data from 24 lakes were compiled along with geomorphic information on each location. Station records were investigated, and annual and period-of-record regression equations are given for each station. Short record length (average of 2.25 years) limits the value of individual station data. Data from rivers in other midwestern states were investigated for longer-term variability. Average annual sediment loads were computed, using the period-of-record regression equation and the flow duration table for each station. These annual loads and the annual loads from the lake sedimentation studies were combined with watershed boundaries and physiographic and geomorphic data to delineate 11 Sediment Yield Areas (SYAs) within the state. Linear and multiple regression equations are presented for each SYA, and example problems outline use of the equations. Separate analyses are presented for stations on the Illinois and Mississippi Rivers.publishedpeer reviewedOpe

Sediment Yield of Streams in Northern and Central Illinois

published or submitted for publicationis peer reviewedOpe

The EUCAMS gear partnership - a model of industry/academic collaboration

Challenges in maintenance systems can pose multi-faceted problems, which are difficult to resolve alone. Over a four year period, a partnership evolved a vision for tackling the understanding of fundamentally difficult mechanical failures and their detection, with potential for practical exploitation of the solutions. The partnership assembled a team of researchers and far-sighted project management, to undertake a study of gearbox failures, including finite element modelling, gear testing, and signal analysis. The partnership trained a series of doctoral and postdoctoral staff in running an integrated project, coping with changes in staffing and locations. The final stages of the work will validate the models and signal processing

Anthropogenic Space Weather

Anthropogenic effects on the space environment started in the late 19th century and reached their peak in the 1960s when high-altitude nuclear explosions were carried out by the USA and the Soviet Union. These explosions created artificial radiation belts near Earth that resulted in major damages to several satellites. Another, unexpected impact of the high-altitude nuclear tests was the electromagnetic pulse (EMP) that can have devastating effects over a large geographic area (as large as the continental United States). Other anthropogenic impacts on the space environment include chemical release ex- periments, high-frequency wave heating of the ionosphere and the interaction of VLF waves with the radiation belts. This paper reviews the fundamental physical process behind these phenomena and discusses the observations of their impacts.Comment: 71 pages, 35 figure

Observations of Radiation Belt Losses Due to Cyclotron Wave-Particle Interactions

Electron loss to the atmosphere plays a critical role in driving dynamics of the Earths Van Allen radiation belts and slot region. This is a review of atmospheric loss of radiation belt electrons caused by plasma wave scattering via Doppler-shifted cyclotron resonance. In particular, the focus is on observational signatures of electron loss, which include direct measurements of precipitating electrons, measured properties of waves that drive precipitation, and variations in the trapped population resulting from loss. We discuss wave and precipitation measurements from recent missions, including simultaneous multi-payload observations, which have provided new insight into the dynamic nature of the radiation belts