title: Adaptive digital twins for energy-intensive industries and their local communities

authors: Walmsley, Timothy Gordon

subjects: digital twin

abstract: Digital Twins (DTs) are high-fidelity virtual models that behave-like, look-like and connect-to a physical system. In this work, the physical systems are operations and processes from energy-intensive industrial plants and their local communities. The creation of DTs demands expertise not just in engineering, but also in computer science, data science, and artificial intelligence. Here, we introduce the Adaptive Digital Twins (ADT) concept, anchored in five attributes inspired by the self-adaptive systems field from software engineering. These attributes are self-learning, self-optimizing, self-evolving, self-monitoring, and self-protection. This new approach merges cutting-edge computing with pragmatic engineering needs. ADTs can enhance decision-making in both the design phase and real-time operation of industrial facilities and allow for versatile 'what-if' scenario simulations. Seven applications within the energy-intensive industries are described where ADTs could be transformative.

text: Adaptive digital twins for energy-intensive industries and their local communities Digital Twins (DTs) are high-fidelity virtual models that behave-like, look-like and connect-to a physical system. In this work, the physical systems are operations and processes from energy-intensive industrial plants and their local communities. The creation of DTs demands expertise not just in engineering, but also in computer science, data science, and artificial intelligence. Here, we introduce the Adaptive Digital Twins (ADT) concept, anchored in five attributes inspired by the self-adaptive systems field from software engineering. These attributes are self-learning, self-optimizing, self-evolving, self-monitoring, and self-protection. This new approach merges cutting-edge computing with pragmatic engineering needs. ADTs can enhance decision-making in both the design phase and real-time operation of industrial facilities and allow for versatile 'what-if' scenario simulations. Seven applications within the energy-intensive industries are described where ADTs could be transformative.

year: 2024

title: Restiad bog development and nutrient dynamics of the dominant species

authors: Clarkson, Beverley R.

subjects: bog succession

abstract: Vegetation and peat in lowland restiad (dominated by Restionaceae) raised bogs on North Island (Waikato region) and Chatham Island, New Zealand, were sampled to investigate the main environmental controls of pattern and change. Vegetation classification based on a chronosequence of Waikato restiad bogs revealed a sequence from sedges, through Empodisma minus, the main peatforming restiad, to phases dominated by a second restiad, Sporadanthus ferrugineus. The sequence paralleled temporal successional patterns and was used for interpreting plant-nutrient dynamics along a successional gradient. As succession proceeds, von Post (an index of peat decomposition), total P, total N and % ash in peat decrease. Empodisma was considered to be the key species in restiad bog development. It is tolerant of a wide environmental range, establishing early in minerotrophic wetlands to initiate restiad bog development, and persisting through to late ombrotrophic phases. On Chatham Island, the ecological role of Sporadanthus traversii in restiad bog development is similar to Empodisma in Waikato, being the main peat former and occupying a wide environmental range. Peat under S. traversii had significantly higher total N, total K, available P, bulk density and von Post, and lower pH than Waikato peats under S. ferrugineus or Empodisma. This was attributed to a strong oceanic influence and long history of sea-bird nutrient inputs. 
Nutrient responses in the heath and restiad components of the bog were compared by measuring plant ¹⁵N natural abundance across N and P gradients. Heath shrubs revealed considerable isotopic variation (-2.03 to - 15.55 for Leptospermum scoparium), with foliar δ¹⁵N strongly positively correlated with P concentrations in foliage and peat. In contrast, restiad species revealed little isotopic variation, with Empodisma and S. traversii having δ¹⁵N levels around 0‰, and S. ferrugineus being significantly more depleted (mean -4.97‰). The differences in ii isotopic signatures between heath shrubs and restiads were linked to contrasting nutrient demands, acquisition mechanisms, and root morphology. Leptospermum shrubs on low nutrient peats were stunted, with low foliar %P and high N:P ratios, suggesting they were P-limited. The concurrence of δ¹⁵N depletion and %P in plant tissues suggests N fractionation is promoted by P limitation. In contrast, the constancy in δ¹⁵N of the restiad species through the nutrient gradients indicates these may not be P-limited. 
The contrasting δ¹⁵N signatures of co-habiting Empodisma and S. ferrugineus in late successional bogs suggest the species are accessing different sources of N. Empodisma has a thick layer of cluster roots overlying the deeper S. ferrugineus roots, and would be better positioned to intercept aerially derived N. The hypothesis that this root disposition allows Empodisma to preferentially access the primary N input from rainfall was tested using a ¹⁵N-enriched tracer. At plots codominated by Empodisma and S.ferrugineus, 1.6 mmoles m-2 of 99 atom% excess ¹⁵N as (NH4)2S04 was applied to the peat surface, followed by deionised water, simulating a rainfall event of 34 mm. After 5 hours, cores were harvested and analysed for ¹⁵N. Approximately 90% of the recovered isotope was in the upper Empodisma root layer. Seven weeks after tracer application, young shoots of Empodisma were significantly enriched whereas adjacent Sporadanthus shoots were not. The results confirm that species acquire nutrients from different rooting zones, with Empodisma accessing nutrients at the surface from rainfall and S. ferrugineus acquiring nutrients from deeper peat layers. Niche differentiation facilitates species co-existence, which, on a successional time scale, may be a mechanism for slowing the rate of competitive displacement.

text: Restiad bog development and nutrient dynamics of the dominant species Vegetation and peat in lowland restiad (dominated by Restionaceae) raised bogs on North Island (Waikato region) and Chatham Island, New Zealand, were sampled to investigate the main environmental controls of pattern and change. Vegetation classification based on a chronosequence of Waikato restiad bogs revealed a sequence from sedges, through Empodisma minus, the main peatforming restiad, to phases dominated by a second restiad, Sporadanthus ferrugineus. The sequence paralleled temporal successional patterns and was used for interpreting plant-nutrient dynamics along a successional gradient. As succession proceeds, von Post (an index of peat decomposition), total P, total N and % ash in peat decrease. Empodisma was considered to be the key species in restiad bog development. It is tolerant of a wide environmental range, establishing early in minerotrophic wetlands to initiate restiad bog development, and persisting through to late ombrotrophic phases. On Chatham Island, the ecological role of Sporadanthus traversii in restiad bog development is similar to Empodisma in Waikato, being the main peat former and occupying a wide environmental range. Peat under S. traversii had significantly higher total N, total K, available P, bulk density and von Post, and lower pH than Waikato peats under S. ferrugineus or Empodisma. This was attributed to a strong oceanic influence and long history of sea-bird nutrient inputs. 
Nutrient responses in the heath and restiad components of the bog were compared by measuring plant ¹⁵N natural abundance across N and P gradients. Heath shrubs revealed considerable isotopic variation (-2.03 to - 15.55 for Leptospermum scoparium), with foliar δ¹⁵N strongly positively correlated with P concentrations in foliage and peat. In contrast, restiad species revealed little isotopic variation, with Empodisma and S. traversii having δ¹⁵N levels around 0‰, and S. ferrugineus being significantly more depleted (mean -4.97‰). The differences in ii isotopic signatures between heath shrubs and restiads were linked to contrasting nutrient demands, acquisition mechanisms, and root morphology. Leptospermum shrubs on low nutrient peats were stunted, with low foliar %P and high N:P ratios, suggesting they were P-limited. The concurrence of δ¹⁵N depletion and %P in plant tissues suggests N fractionation is promoted by P limitation. In contrast, the constancy in δ¹⁵N of the restiad species through the nutrient gradients indicates these may not be P-limited. 
The contrasting δ¹⁵N signatures of co-habiting Empodisma and S. ferrugineus in late successional bogs suggest the species are accessing different sources of N. Empodisma has a thick layer of cluster roots overlying the deeper S. ferrugineus roots, and would be better positioned to intercept aerially derived N. The hypothesis that this root disposition allows Empodisma to preferentially access the primary N input from rainfall was tested using a ¹⁵N-enriched tracer. At plots codominated by Empodisma and S.ferrugineus, 1.6 mmoles m-2 of 99 atom% excess ¹⁵N as (NH4)2S04 was applied to the peat surface, followed by deionised water, simulating a rainfall event of 34 mm. After 5 hours, cores were harvested and analysed for ¹⁵N. Approximately 90% of the recovered isotope was in the upper Empodisma root layer. Seven weeks after tracer application, young shoots of Empodisma were significantly enriched whereas adjacent Sporadanthus shoots were not. The results confirm that species acquire nutrients from different rooting zones, with Empodisma accessing nutrients at the surface from rainfall and S. ferrugineus acquiring nutrients from deeper peat layers. Niche differentiation facilitates species co-existence, which, on a successional time scale, may be a mechanism for slowing the rate of competitive displacement.

year: 2005

title: Cultural justice, ethics and teaching

authors: Nairn, Ray

subjects: Maori

abstract: Te Tiriti o Waitangi provides both a basis for cultural justice in this society and an explication of the term; each of the articles identifying a significant aspect of cultural justice. First, there is the guarantee to the Maori signatories that the Crown would protect their independence - tino rangatiratanga, (also read as authority, autonomy or self-determination) [Article II]. In Article III Maori are promised that they will also have the “Rights and Privileges of British subjects”. Finally, in Article I, Maori cede to the Crown the right to govern, to make laws to protect all peoples from the evil consequences of lawlessness. The 1835 Declaration of Independence located legislative authority in the Wakaminenga (the gathered rangatira meeting in Congress); and in 1840, in the context of the Crown promises, Maori authorised the Crown to exercise that authority. For Maori Te Tiriti specifies cultural justice for interactions between Maori and settlers in the new society. Maori are guaranteed the right to self-determination (and the economic and social resources to make that practical) in their relations with New Zealand society. They are also entitled to the same opportunities as other citizens. The latter rights, embodied in local legislation and international covenants to which we are signatory, are not alternatives to the prior right of Maori people to their (cultural) autonomy. The exercise of legislative and organisational authority must be exercised in a manner consistent with the promises which clearly requires consultation and negotiation with Maori.

text: Cultural justice, ethics and teaching Te Tiriti o Waitangi provides both a basis for cultural justice in this society and an explication of the term; each of the articles identifying a significant aspect of cultural justice. First, there is the guarantee to the Maori signatories that the Crown would protect their independence - tino rangatiratanga, (also read as authority, autonomy or self-determination) [Article II]. In Article III Maori are promised that they will also have the “Rights and Privileges of British subjects”. Finally, in Article I, Maori cede to the Crown the right to govern, to make laws to protect all peoples from the evil consequences of lawlessness. The 1835 Declaration of Independence located legislative authority in the Wakaminenga (the gathered rangatira meeting in Congress); and in 1840, in the context of the Crown promises, Maori authorised the Crown to exercise that authority. For Maori Te Tiriti specifies cultural justice for interactions between Maori and settlers in the new society. Maori are guaranteed the right to self-determination (and the economic and social resources to make that practical) in their relations with New Zealand society. They are also entitled to the same opportunities as other citizens. The latter rights, embodied in local legislation and international covenants to which we are signatory, are not alternatives to the prior right of Maori people to their (cultural) autonomy. The exercise of legislative and organisational authority must be exercised in a manner consistent with the promises which clearly requires consultation and negotiation with Maori.

year: 1993