Oscillatory Loading Can Alter the Velocity Dependence of Ice‐on‐Rock Friction

Abstract Rate and state frictional parameters are typically determined using two types of experimental protocols: velocity steps and slide‐hold‐slide events. Here we take a new approach by examining the frictional response to controlled, harmonic oscillations in load point velocity. We present a Matlab graphical user interface software package, called RSFitOSC, that allows users to easily determine frictional parameters by fitting oscillation events using the rate and state friction equations. We apply our new methods to a set of ice‐rock friction experiments conducted over a temperature range of −16.4°C to −2°C, and described in a companion paper: McCarthy et al. (2021, https://doi.org/10.1002/essoar.10509831.110.1002/essoar.10509831.1). Values of the frictional stability parameter (a–b) determined from oscillations reveal dominantly velocity‐weakening behavior across the entire range of experimental conditions. However, values of (a–b) determined from velocity steps in the same experiments yield velocity‐strengthening behavior. We also show that the elastic stiffness of the ice‐rock system depends on the temperature, and is unlikely to be explained by changes in the elastic properties of ice. Load point velocity oscillations induce oscillations in applied shear stress. Many natural fault systems exhibit slip behaviors that depend on harmonic oscillations in applied tidal stresses. Our new method provides a way to study how frictional properties directly depend on parameters relevant to tidal forcing, and how oscillatory loading must be considered when extracting friction parameters

Pathways to deep decarbonisation in 2050: How Australia can prosper in a low carbon world

The 2014 report and the associated Technical Report elaborate on the work undertaken to prepare the Australian chapter of the DDPP 2014 report. They provide additional Australian context and technical detail about the modelling and analysis. The accompanying Technical Report provides more information on the modelling framework, assumptions and results of the sectoral analysis. The analysis presents an illustrative deep decarbonisation pathway for Australia; just one of many possible pathways, and has been developed using a combination of well-established modelling tools with a prominent role for least cost economic modelling methodologyThis report was commisioned by ClimateWorks Australi

Pathways to deep decarbonization

This report stated the key concepts of decarbonization of 15 leading economies aiming at limiting global warming by 2 degrees Celsius. The report was presented to UN Secretary-General Ban Ki-moon in support of the UN Climate Leaders' Summit in New York on September 23, 2014 and the UNFCCC COP21, where the historic Paris Climate Agreement was signed in December 2015.Don

Illusions of Utopia: When Prison Architects (Reluctantly) Play Tetris

Although prisons are increasingly built away from cities, prison architects are imagining prisons as cities. Such an urban metaphor is perhaps unsurprising; both the prison and the city are often assumed to be relatively bounded places, prisons arguably resembling self-sufficient cities with facilities such as accommodation, classrooms, workshops, laundries, health clinics and gardens contained within their walls. The vocabulary of the city is also pervasive when justifying prison architecture. In this chapter we consider why prison architects use the metaphor of the city to describe the prisons they design, using terminology such as ‘walled bungalows’, ‘penitentiary houses’, ‘vertical prisons’ and ‘cell apartments’, and we examine the significance of this rather dystopian urban imaginary in allowing architects to retain some agency within a design process which minimises their creative and political input

In situ carbon mineralization in ultramafic rocks: Natural processes and possible engineered methods

In this invited review, we summarize the main results of ongoing research on “in situ” carbon mineralization in ultramafic rocks, including outcrop studies in Oman (e.g., [1, 2]), investigation of carbon mass transfer in subduction zones from the Oman Drilling Project (e.g., [3-7]), laboratory investigations (e.g., [8-12]) and numerical modeling (e.g., [13-17]) of the pressure of crystallization and reaction-driven cracking, and assessment of the rate, cost and capacity of various proposed methods for engineered carbon mineralization [18, 19]