Characterising Radio Emissions in Cosmic Filaments

<p>A growing number of radio studies probe galaxy clusters into the low-power regime in which star formation is the dominant source of radio emission. However, at the time of writing no comparably deep observations have focused exclusively on the radio populations of cosmic filaments. This thesis describes the ATCA 2.1 GHz observations and subsequent analysis of two such regions - labelled Zone 1 (between clusters A3158 and A3125/A3128) and Zone 2 (between A3135 and A3145) - in the Horologium-Reticulum Supercluster (HRS). Source count profiles of both populations are discussed and a radio luminosity function for Zone 1 is generated. While the source counts of Zone 2 appear to be consistent with expected values, Zone 1 exhibits an excess of counts across a wide flux range (1 mJy</p>

Characterising Radio Emissions in Cosmic Filaments

<p>A growing number of radio studies probe galaxy clusters into the low-power regime in which star formation is the dominant source of radio emission. However, at the time of writing no comparably deep observations have focused exclusively on the radio populations of cosmic filaments. This thesis describes the ATCA 2.1 GHz observations and subsequent analysis of two such regions - labelled Zone 1 (between clusters A3158 and A3125/A3128) and Zone 2 (between A3135 and A3145) - in the Horologium-Reticulum Supercluster (HRS). Source count profiles of both populations are discussed and a radio luminosity function for Zone 1 is generated. While the source counts of Zone 2 appear to be consistent with expected values, Zone 1 exhibits an excess of counts across a wide flux range (1 mJy</p>

Air Particulate Matter in Pollluted New Zealand Urban Environments: Sources, Patterns and Transport

<p>During the winters of 2010 and 2011, three intensive particulate matter (PM) monitoring campaigns were undertaken in Masterton, Alexandra and Nelson, New Zealand. The goal of these campaigns was, for the first time, to identify the sources and factors contributing to elevated PM concentrations on an hourly time-scale. In each location, hourly coarse (PM₁₀-₂.₅; particles with aerodynamic diameters 2.5 μm < d < 10 μm) and fine (PM₂.₅; particles with aerodynamic diameters < 2.5 μm) samples, PM₁₀ (particles with aerodynamic diameters < 10 μm, incorporating the coarse and fine fractions) concentrations and meteorological variables were collected from a number of sites. Using elemental concentrations determined from ion beam analysis and black carbon concentrations determined from light reflection for each hourly sample, PM sources and their contributions on an hourly time-scale were identified using positive matrix factorization (PMF). In Masterton, where two sampling sites were employed, PM₁₀ concentrations displayed distinct diurnal cycles, with peak concentrations occurring in the evening (7 pm–midnight) and in the morning (7–9 am). Four PM sources were identified (biomass burning, marine aerosol, crustal matter and vehicles) at each of the sites and biomass burning was identified as the most dominant source of PM₁₀ during both the evening and morning. One of the sites experienced consistently higher PM₁₀ concentrations and katabatic flows across Masterton were identified to be the main contributor to this phenomenon. In Alexandra and Nelson, three sampling sites on a horizontal transect (upwind, central and downwind of the general katabatic flow pathway) and a fourth site located centrally, but at a height of 26 m, were incorporated in a novel study design. Each of the sites in Alexandra and Nelson also showed diurnal patterns in PM₁₀ concentrations. The central site in Alexandra experienced consistently higher PM₁₀ concentrations and four PM₁₀ sources were identified at each of the sites (biomass burning, marine aerosol, vehicles and crustal matter). Biomass burning was identified as the main source of PM₁₀ throughout the day at each of the sites. The convergence of numerous katabatic flows was identified as the contributing factor to the elevated PM₁₀ concentrations measured at the central site. In Nelson, five PM sources were identified at each of the sites (biomass burning, vehicles, marine aerosol, shipping sulfate and crustal matter) and biomass burning was identified as the dominant source of PM₁₀ throughout the day. Katabatic flows were also identified to play an important role in PM₁₀ transport. Analyses of source-specific (wood combustion and vehicles) PM samples was also undertaken, and the results of these analyses are included in this thesis.</p>

Air Particulate Matter in Pollluted New Zealand Urban Environments: Sources, Patterns and Transport

<p>During the winters of 2010 and 2011, three intensive particulate matter (PM) monitoring campaigns were undertaken in Masterton, Alexandra and Nelson, New Zealand. The goal of these campaigns was, for the first time, to identify the sources and factors contributing to elevated PM concentrations on an hourly time-scale. In each location, hourly coarse (PM₁₀-₂.₅; particles with aerodynamic diameters 2.5 μm < d < 10 μm) and fine (PM₂.₅; particles with aerodynamic diameters < 2.5 μm) samples, PM₁₀ (particles with aerodynamic diameters < 10 μm, incorporating the coarse and fine fractions) concentrations and meteorological variables were collected from a number of sites. Using elemental concentrations determined from ion beam analysis and black carbon concentrations determined from light reflection for each hourly sample, PM sources and their contributions on an hourly time-scale were identified using positive matrix factorization (PMF). In Masterton, where two sampling sites were employed, PM₁₀ concentrations displayed distinct diurnal cycles, with peak concentrations occurring in the evening (7 pm–midnight) and in the morning (7–9 am). Four PM sources were identified (biomass burning, marine aerosol, crustal matter and vehicles) at each of the sites and biomass burning was identified as the most dominant source of PM₁₀ during both the evening and morning. One of the sites experienced consistently higher PM₁₀ concentrations and katabatic flows across Masterton were identified to be the main contributor to this phenomenon. In Alexandra and Nelson, three sampling sites on a horizontal transect (upwind, central and downwind of the general katabatic flow pathway) and a fourth site located centrally, but at a height of 26 m, were incorporated in a novel study design. Each of the sites in Alexandra and Nelson also showed diurnal patterns in PM₁₀ concentrations. The central site in Alexandra experienced consistently higher PM₁₀ concentrations and four PM₁₀ sources were identified at each of the sites (biomass burning, marine aerosol, vehicles and crustal matter). Biomass burning was identified as the main source of PM₁₀ throughout the day at each of the sites. The convergence of numerous katabatic flows was identified as the contributing factor to the elevated PM₁₀ concentrations measured at the central site. In Nelson, five PM sources were identified at each of the sites (biomass burning, vehicles, marine aerosol, shipping sulfate and crustal matter) and biomass burning was identified as the dominant source of PM₁₀ throughout the day. Katabatic flows were also identified to play an important role in PM₁₀ transport. Analyses of source-specific (wood combustion and vehicles) PM samples was also undertaken, and the results of these analyses are included in this thesis.</p>

Indonesia will struggle to attain climate goals

Significance In July, it expressed optimism about achieving net-zero emissions by “2060 or sooner”. This will require a phasing out of coal-fired power plants, currently the dominant source of energy in the country. Impacts Jakarta may include its 2060 target explicitly in future updates of its Nationally Determined Contribution to action against climate change. Indonesian oil and gas firms will step up opposition to the government’s plans to introduce a carbon tax. The government will redouble commitment to reforestation efforts.

Reconstructing the Changes in Sedimentation and Source Provenance in an East African Hydropower Reservoirs: A Case Study of Nyumba ya Mungu in Tanzania

This study aimed to reconstruct the sedimentation rates over time and identify the changing sources of sediment in a major hydropower reservoir in Tanzania, the Nyumba ya Mungu (NYM). Fallout 210Pb measurements were used to estimate age of sediment deposits and broad changes in sedimentation rates were reconstructed. Sedimentation peaks were cross referenced to geochemical profiles of allogenic and autogenic elemental constituents of the sediment column to confirm a causal link. Finally, geochemical fingerprinting of the sediment cores and potential sources were compared using a Bayesian mixing model (MixSIAR) to attribute the dominant riverine and land use sources to the reservoir together with changes through recent decades. Reservoir sedimentation generally increased from 0.1 g cm−2 yr−1 in the lower sediment column to 1.7 g cm−2 yr−1 in the most recent deposits. These results correlated to changes in allogenic and autogenic tracers. The model output pointed to one of two major tributaries, the Kikuletwa River with 60.3%, as the dominant source of sediment to the entire reservoir, while the other tributary, Ruvu River, contributed approximately 39.7%. However, downcore unmixing results indicated that the latest increases in sedimentation seem to be mainly driven by an increased contribution from the Ruvu River. Cultivated land (CU) was shown to be the main land use source of riverine sediment, accounting for 38.4% and 44.6% in Kikuletwa and Ruvu rivers respectively. This study explicitly demonstrated that the integration of sediment tracing and dating tools can be used for quantifying the dominant source of sediment infilling in East African hydropower reservoirs. The results underscore the necessity for catchment-wide management plans that target the reduction of both hillslope erosion reduction and the sediment connectivity from hillslope source areas to rivers and reservoirs, which will help to maintain and enhance food, water and energy security in Eastern Africa.

EVALUATION OF THE USAGE OF GEOTHERMAL ENERGY IN THE HOT WATER BOILER ROOM STRED I.

The dominant source of energy in the hot water boiler house Stred I. in Velky Meder is geothermal energy, which is drawn from the VM -1 well, which was drilled in its courtyard in 2015. Based on documents and personal inspections of this boiler room, I created a geothermal circuit scheme of this hot water boiler room, where the experimental measurements took place. Part of this paper is a diagram of the geothermal circuit, a comparison of measured values ​​within a selected characteristic day for summer and winter operation in 2020. Finally, the operation of the usage of geothermal energy in the hot water boiler room Stred I. is evaluated on all these indicators.

Identification of the Major Noise Energy Sources in Rail Vehicles Moving at a Speed of 200 km/h

In this work, the problematic identification of the main sources of noise occurring from the exploitation of railway vehicles moving at a speed of 200 km/h were analyzed. Within the conducted experimental research, the testing fields were appointed, measurement apparatus selected, and a methodology for conducting measurements was defined, including the assessment of noise on a curve and straight track for electric multiple units of the so-called Pendolino, an Alstom type ETR610 series ED25 train. The measurements were made using a microphone camera Bionic S-112 at a distance of 22 m from the track axis. As a result of the conducted experimental research, it was indicated that the noise resulting from vibrations arising at the wheel-rail contact (rolling noise) was the dominant source of sound.