Carbon mitigation from agroforestry in salinized low rainfall farmland landscapes

Efforts to reduce greenhouse gas emissions have become a global priority and the land sector can contribute significantly to achieving this via a range of mitigation strategies such as the biosequestration of carbon and substitution of fossil fuels through bioenergy. However, the implementation of land sector mitigation is constrained by several uncertainties and knowledge gaps particularly within low rainfall (300 to 400 mm yr-1) farmland environments. This thesis examines aspects of land sector mitigation through reforestation systems integrated into dryland (300 to 400 mm yr-1) farming systems in Western Australia. The uncertainties that are examined in this thesis include (a) estimation of tree root carbon storage, (b) exploring whether carbon mitigation can be achieved through new agroforestry systems that reduce competitive effects and (c) assessing the sustainability of these new systems in terms of nutrient removal. Estimates of below ground biomass pools are critical to establishing carbon fluxes on regional scales which can then be applied in global modeling of climate change mitigation strategies. A new methodology for tree below-ground biomass estimation was developed, including a purpose-designed coring machine. Monte Carlo simulation was used to assess the accuracy of a range of sampling regimes through estimates of uncertainty (precision) and bias (error) and these sampling methods were subsequently used to develop allometric relationships to estimate the carbon mitigation potential of tree phases integrated into agricultural systems. The implications of integrating tree phases into agricultural systems and the effects of this on the sustainability of existing farming systems were investigated. This included an assessment of potential land use synergies targeting abandoned or marginal land for multiple land use outcomes via landscape rehabilitation and carbon mitigation. The integration of short tree phases (3 years) into low rainfall salinized farmland for the purpose of soil salinity amelioration was shown to have additive environmental benefits as a potential source of biomass feedstock for renewable energy. Allometric relationships were developed for three candidate species (Eucalyptus globulus, E. occidentalis and Pinus radiata) and their carbon storage was assessed based on whole tree destructive sampling, including below ground sampling. The biomass production for different planting density and landscape placement strategies, and for different tree components was estimated to assist in future development of harvesting systems and management of nutrient removal. It was shown that tree phases inserted into farming systems for the purpose of ground water control could potentially serve as a biomass feedstock for renewable energy, either bioenergy for power generation or as feedstock for lignocellulosic (second generation) biofuel, thus offsetting the use of non-renewable fossil fuel. The sustainability of these systems was investigated to determine their impact on current farming systems and the potential removal of nutrients. Harvesting regimes that remove woody biomass while retaining leaves on site are likely to be more sustainable from a nutrient management perspective. A nutrient assimilation index was developed for these short rotation tree crop systems to aid the management of nutrient removal. The removal of nutrients via a short (3 year) tree phase was less than the cereal cropping systems currently in place and had potential to retrieve leached nutrients from deeper in the soil profile. Planting of tree and shrub species in severely salinized abandoned farmland was shown to be a potential avenue for carbon mitigation, and a resultant positive land use change. With species selection, management of stand density and landscape position, tree growth and carbon sequestration can be manipulated with rates of sequestration of 1.1 to 2.3 t ha-1 yr-1 following 8 years growth in the highly saline environment. A combination of shrub (Atriplex nummularia) and tree (Eucalyptus occidentalis) species were used to mimic natural saline wetland succession and were successful in rehabilitating degraded farmland while effectively sequestering carbon and mitigating atmospheric CO2. The challenge remains to integrate these mitigation initiatives and systems into existing economic and social environments and for them to be accepted as typical economic activities. This is not only a challenge from the scientific view point, but encompasses social and political aspects which often makes its application difficult

Rejection in Łukasiewicz's and Słupecki's Sense

The idea of rejection originated by Aristotle. The notion of rejection was introduced into formal logic by Łukasiewicz [20]. He applied it to complete syntactic characterization of deductive systems using an axiomatic method of rejection of propositions [22, 23]. The paper gives not only genesis, but also development and generalization of the notion of rejection. It also emphasizes the methodological approach to biaspectual axiomatic method of characterization of deductive systems as acceptance (asserted) systems and rejection (refutation) systems, introduced by Łukasiewicz and developed by his student Słupecki, the pioneers of the method, which becomes relevant in modern approaches to logic

Próby zwiększenia szybkości transmisji w sieci teleksowej. Przegląd Zagadnień Łączności, 1968, nr 7 (82)

Komentarz do artykułu oraz tłumaczenie na podstawie artykuł

Dynamic Stability of the Periodic and Aperiodic Structures of the Bernoulli-Euler Beams

The study analyzed the influence of periodic and aperiodic stiffness distribution for the four-element Bernoulli-Euler beam on the first two eigenfrequencies and the dynamic stability of the system. The influence of increasing the ratio of cross-sections of the analyzed elements was also analyzed. Significant differences were found in eigenfrequencies and dynamic stability. Using the variational Hamilton principle, the equation of motion was derived, on the basis of which the values of the eigenfrequencies were determined, and the transformation into the form of the Mathieu equation made it possible to determine the dynamic stability for the analyzed structures

Influence of PNM-0.38PT Defect on Transmission of Multilayer Periodic Phononic Structure

In this work, the impact of the defect on the transmission of a mechanical wave in a periodic quasi-one-dimensional structure was investigated. The multilayer structure was made of PLA and air, while the defect layer was PNM-0.38PT with a significantly higher value of acoustic impedance in relation to the materials of the base structure. The influence of the position of the defect in the structure and its thickness was analysed. Transmission as a function of frequency was determined using the Transfer Matrix Method algorithm. The work showed the presence of band gaps in the analyzed structures. The influence of the symmetry of structures and substructures on the transmission of a mechanical wave was investigated. The influence of the number of layers with very low acoustic impedance (air) on the number of high transmission peaks with a small half-width was also demonstrated

Mitigation of carbon using Atriplex nummularia revegetation

The use of abandoned or marginally productive land to mitigate greenhouse gas emissions may avoid competition with food and water production. Atriplex nummularia Lindl. is a perennial shrub commonly established for livestock forage on saline land, however, its potential for carbon mitigation has not been systematically evaluated. Similarly, although revegetation is an allowable activity to mitigate carbon within Article 3.4 of the United Nations Framework Convention on Climate Change's Kyoto Protocol, there is a paucity of information on rates of carbon mitigation in soils and biomass through this mechanism. For six sites where A. nummularia had been established across southern Australia four were used to assess changes in soil carbon storage and four were used to develop biomass carbon sequestration estimates. A generalised allometric equation for above and below ground biomass was developed, with a simple crown volume index explaining 81% of the variation in total biomass. There were no significant differences in soil organic carbon storage to 0.3 m or 2 m depth compared to existing agricultural land-use. Between 2.2 and 8.3 Mg C ha−1 or 0.2–0.6 Mg C ha−1 yr−1 was sequestered in above and below ground biomass and this translates to potential total sequestration of 1.1–3.6 Tg C yr−1 on saline land across Australia. Carbon income and forage grazing may thus provide a means to finance the stabilization of compromised land

Baffling perforation of the colon

Idiopathic perforation of the colon is extremely unusual and unexpected, with a very limited number of published reports. The condition’s definition depends on the absence of any detectable pathology in the bowel wall that could be responsible for the perforation. A 62-year-old male patient presented with acute thrombosis of the brachial artery. This was successfully treated with an open thrombectomy and systemic anticoagulation, with rapid resolution of the symptoms. During the hospital stay the patient had regular bowel movements and no abdominal complaints. Suddenly he complained of acute abdominal pain. Physical examination and emergency CT scan of the abdomen were consistent with generalized peritonitis. Emergency laparotomy revealed two perforations of the mid-sigmoid colon, each measuring 1.5 x 1.5 cm, an

Seasonal timing for estimating carbon mitigation in revegetation of abandoned agricultural land with high spatial resolution remote sensing

Dryland salinity is a major land management issue globally, and results in the abandonment of farmland. Revegetation with halophytic shrub species such as Atriplex nummularia for carbon mitigation may be a viable option but to generate carbon credits ongoing monitoring and verification is required. This study investigated the utility of high-resolution airborne images (Digital Multi-Spectral Imagery (DMSI)) obtained in two seasons to estimate carbon stocks at the plant- and stand-scale. Pixel-scale vegetation indices, sub-pixel fractional green vegetation cover for individual plants, and estimates of the fractional coverage of the grazing plants within entire plots, were extracted from the high-resolution images. Carbon stocks were correlated with both canopy coverage (R2: 0.76–0.89) and spectral-based vegetation indices (R2: 0.77–0.89) with or without the use of the near-infrared spectral band. Indices derived from the dry season image showed a stronger correlation with field measurements of carbon than those derived from the green season image. These results show that in semi-arid environments it is better to estimate saltbush biomass with remote sensing data in the dry season to exclude the effect of pasture, even without the refinement provided by a vegetation classification. The approach of using canopy cover to refine estimates of carbon yield has broader application in shrublands and woodlands

Mission and system architecture for an operational network of earth observation satellite nodes

Nowadays, constellations and distributed networks of satellites are emerging as clear development trends in the space system market to enable augmentation, enhancement, and possibilities of new applications for future Earth Observation (EO) missions. While the adoption of these satellite architectures is gaining momentum for the attaining of ever more stringent application requirements and stakeholder needs, the efforts to analyze their benefits and suitability, and to assess their impact for future programmes remains as an open challenge to the EO community. In this context, this paper presents the mission and system architecture conceived during the Horizon 2020 ONION project, a European Union research activity that proposes a systematic approach to the optimization of EO space infrastructures. In particular, ONION addressed the design of complementary assets that progressively supplement current programs and took part in the exploration of needs and implementation of architectures for the Copernicus Space Component for EO. Among several use cases considered, the ONION project focused on proposing system architectures to provide improved revisit time, data latency and image resolution for a demanding application scenario of interest: Marine Weather Forecast (MWF). A set of promising system architectures has been subject of a comprehensive assessment, based on mission analysis expertise and detailed simulation for evaluating several key parameters such as revisit time and data latency of each measurement of interest, on-board memory evolution and power budget of each satellite of the constellation, ground station contacts and inter-satellite links. The architectures are built with several heterogeneous satellite nodes distributed in different orbital planes. Each platform can embark different instrument sets, which provide the required measurements for each use case. A detailed mission analysis has then been performed to the selected architecture for the MWF use case, including a refined data flow analysis to optimize system resources; a refined power budget analysis; a delta-V and a fuel budget analysis considering all the possible phases of the mission. This includes from the correction of launcher injection errors and acquisition of nominal satellite position inside the constellation, orbit maintenance to control altitude, collision avoidance to avoid collision with space debris objects and end-of-life (EOL) disposal to comply with EOL guidelines. The relevance of the system architecture selected for the MWF has been evaluated for three use cases of interest (Arctic sea-ice monitoring, maritime fishery pressure and aquaculture, agricultural hydric stress) to show the versatility and the feasibility of the chosen architecture to be adapted for other EO applications.This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 687490