University of Wollongong

About: University of Wollongong is a education organization based out in Wollongong, New South Wales, Australia. It is known for research contribution in the topics: Population & Context (language use). The organization has 15674 authors who have published 46658 publications receiving 1197471 citations. The organization is also known as: UOW & Wollongong University.

Millennial and orbital variations of El Niño/Southern Oscillation and high-latitude climate in the last glacial period

Abstract: The El Nino/Southern Oscillation (ENSO) phenomenon is believed to have operated continuously over the last glacial–interglacial cycle1. ENSO variability has been suggested to be linked to millennial-scale oscillations in North Atlantic climate during that time2,3, but the proposals disagree on whether increased frequency of El Nino events, the warm phase of ENSO, was linked to North Atlantic warm or cold periods. Here we present a high-resolution record of surface moisture, based on the degree of peat humification and the ratio of sedges to grass, from northern Queensland, Australia, covering the past 45,000 yr. We observe millennial-scale dry periods, indicating periods of frequent El Nino events (summer precipitation declines in El Nino years in northeastern Australia). We find that these dry periods are correlated to the Dansgaard–Oeschger events—millennial-scale warm events in the North Atlantic climate record—although no direct atmospheric connection from the North Atlantic to our site can be invoked. Additionally, we find climatic cycles at a semiprecessional timescale (∼11,900 yr). We suggest that climate variations in the tropical Pacific Ocean on millennial as well as orbital timescales, which determined precipitation in northeastern Australia, also exerted an influence on North Atlantic climate through atmospheric and oceanic teleconnections.

Recent progress on programming methods for industrial robots

Abstract: Although an automated flexible production cell is an intriguing prospect for small to median enterprises (SMEs) in current global market conditions, the complexity of programming remains one of the major hurdles preventing automation using industrial robots for SMEs. This paper provides a comprehensive review of the recent research progresses on the programming methods for industrial robots, including online programming, offline programming (OLP), and programming using Augmented Reality (AR). With the development of more powerful 3D CAD/PLM software, computer vision, sensor technology, etc, new programming methods suitable for SMEs are expected to grow in years to come.

Comparisons of the Orbiting Carbon Observatory-2 (OCO-2) X CO 2 measurements with TCCON

Abstract: NASA's Orbiting Carbon Observatory-2 (OCO-2) has been measuring carbon dioxide column-averaged dry-air mole fraction, X_(CO_2), in the Earth's atmosphere for over 2 years. In this paper, we describe the comparisons between the first major release of the OCO-2 retrieval algorithm (B7r) and X_(CO2) from OCO-2's primary ground-based validation network: the Total Carbon Column Observing Network (TCCON). The OCO-2 X_(CO_2) retrievals, after filtering and bias correction, agree well when aggregated around and coincident with TCCON data in nadir, glint, and target observation modes, with absolute median differences less than 0.4 ppm and RMS differences less than 1.5 ppm. After bias correction, residual biases remain. These biases appear to depend on latitude, surface properties, and scattering by aerosols. It is thus crucial to continue measurement comparisons with TCCON to monitor and evaluate the OCO-2 X_(CO_2) data quality throughout its mission.

Management of Battery-Supercapacitor Hybrid Energy Storage and Synchronous Condenser for Isolated Operation of PMSG Based Variable-Speed Wind Turbine Generating Systems

Abstract: Standalone operation of a wind turbine generating system under fluctuating wind and variable load conditions is a difficult task. Moreover, high reactive power demand makes it more challenging due to the limitation of reactive capability of the wind generating system. A Remote Area Power Supply (RAPS) system consisting of a Permanent Magnet Synchronous Generator (PMSG), a hybrid energy storage, a dump load and a mains load is considered in this paper. The hybrid energy storage consists of a battery storage and a supercapacitor where both are connected to the DC bus of the RAPS system. An energy management algorithm (EMA) is proposed for the hybrid energy storage with a view to improve the performance of the battery storage. A synchronous condenser is employed to provide reactive power and inertial support to the RAPS system. A coordinated control approach is developed to manage the active and reactive power flows among the RAPS components. In this regard, individual controllers for each RAPS component have been developed for effective management of the RAPS components. Through simulation studies carried out using detailed model in MATLAB Simulink, it has been demonstrated that the proposed method is capable of achieving: a) robust voltage and frequency regulation (in terms of their acceptable bandwidths), b) effective management of the hybrid storage system, c) reactive power capability and inertial support by the synchronous condenser, and d) maximum power extraction from wind.