The rapid integration of inverter-based resources (IBRs) is changing the dynamic behaviour of modern power systems. As synchronous generators are replaced by photovoltaic (PV) inverters, system inertia decreases and frequency stability becomes more difficult to maintain.This paper compares proportional-integral (PI) control and sliding mode control (SMC) for PV inverter regulation in an IEEE 9-bus test system. Synchronous generators are progressively replaced by PV inverters to represent low and high IBR penetration levels. In both cases, active power sharing is provided through frequency-based droop control.Four MATLAB/Simulink scenarios are studied under 10% and 15% load disturbances. The results show that PI control provides smoother and better-damped responses under low IBR penetration. However, its performance deteriorates when penetration level and disturbance magnitude increase. In contrast, SMC improves the frequency nadir and shortens the recovery time under high-penetration and large-disturbance conditions.These findings show that PI and SMC have complementary operating characteristics. PI is more suitable for moderate operating conditions, while SMC provides stronger robustness in low-inertia scenarios. The results provide practical guidance for controller selection in renewable-dominated power systems.
Nitrogen to protein conversion factors (NPCF) are used to estimate the crude protein content based on the nitrogen content of protein sources. Throughout agriculture and including aquaculture, the most used NPCF is 6.25 which relies on two assumptions, (1) all nitrogen comes from proteins and (2) all proteins contain 16% nitrogen. These assumptions do not account for non-protein nitrogen including nucleotides, ammonia, urea, and chitin, or that some proteins have higher or lower nitrogen content than 16% nitrogen. Recognition of flaws in the assumptions has led to the production of species-specific NPCFs; however, NPCFs specific to crustaceans are lacking. There are various NPCFs calculatable for a substance however the present study focused on the NPCFs KA’ and KP. KA’ accounts for assumption two whilst KP accounts for both assumptions therefore KA’ is most comparable to the NPCF 6.25 whereas KP may be more practically applicable. Two NPCFs, KA’ and KP, were calculated for tropical spiny rock lobster (Panulirus ornatus), tiger prawn (Penaeus monodon), and brine shrimp (Artemia salina). Crustacean KA’ values ranged from 4.91–5.58 whereas KP ranged from 3.39 to 5.12. The interspecific deviation from 6.25 highlights the need for species-specific NPCFs to more accurately represent protein compositions.
Background and aims Public transport (PT) users are typically more physically active compared with private vehicle users. This study aimed to determine the variables associated with objectively measured PT use and self-reported walking for transport among infrequent bus users in a regional area of Australia. Methods Analysis of cross-sectional baseline data of 109 infrequent bus users (defined as making an average of ≤ 2 bus trips per week over the past 6 months) in the Tasmanian Trips4Health study. Walking for transport (minutes/week), psychosocial, behavioural, health, and productivity measures were self-reported via questionnaire. Bus use was objectively measured via smartcard (average bus use/week). Multivariable linear regression assessed associations with bus use and walking for transport. Results Participants reporting greater self-efficacy (β = 0.44; 95% CI = 0.00, 0.87), family support for using public transport by catching the bus with them (β = 0.30; 95% CI = 0.03, 0.57) and planned daily travel (β = 0.86; 95% CI = 0.50, 1.22), demonstrated higher weekly bus use. Higher self-reported physical quality-of-life (β = −1.13; 95% CI = −1.86, −0.39) and being a woman (β = −0.54; 95% CI = −1.05, −0.02) were associated with lower weekly bus use. Moderate self-perceived general health was positively associated with walking for transport (β = 150.08; 95% CI = 13.84, 286.31) compared to poor/fair self-perceived health. Participants with regular access to a motor vehicle (β = −181.0; 95% CI = −272.0, −89.92) walked less for transport than those without motor vehicle access. Conclusions Individual and social variables are associated with adults’ PT use and walking for transport. Strategies to enhance PT use and walking for transport should consider self-efficacy, family support, skills to plan PT use, and gender in their design.
Conservation covenants are an innovative legal mechanism that modify private property rights to promote biodiversity benefits. Their use is increasing as governments encourage private land conservation to help meet national and global biodiversity goals, such as the Kunming-Montreal Global Biodiversity Framework. However, existing use of covenants from a variety of countries, including Australia, New Zealand and the United States, highlights some limitations. There is limited explicit accommodation of changing circumstances such as climate impacts; insufficient support to landowners and a need for increased environmental monitoring and compliance oversight. Several actions could be taken to ameliorate these and other law-related impediments, including improved reciprocity between parties to covenants, designing covenants with greater flexibility, and improving integrity mechanisms.
Abstract Many large igneous provinces (LIPs) comprise once contiguous magmatic products that are now fragmented across multiple tectonic plates. Emplacement of these voluminous magmatic products is commonly coeval with, or shortly followed by, fragmentation into constituent domains. However, the Kerguelen LIP, predominantly within the southern Indian Ocean, rifted after an unusually protracted c. 45 Myr interval post‐emplacement. To investigate this protracted post‐emplacement rifting, a recent voyage by the RV Investigator sampled the conjugate margins of the Kerguelen Plateau, William's Ridge (WR) and Broken Ridge (BR) for the first time. Dredged volcanic rocks were characterized using petrographic, geochemical (major and trace element, Sr‐Nd‐Pb‐Hf isotopes) and geochronological (40Ar/39Ar) techniques. Here, we focus on the sampled 82–67 Ma tholeiitic volcanic rocks. The observed geochemical data in conjunction with rare earth element inversion modeling of these Late Cretaceous volcanic rocks reflect plume–ridge interaction with variable assimilation (≤10%) of continental crust. We propose that the Kerguelen plume transported melt to the WR–BR margin during episodes of extension. Extension and magmatism were localized along the rheologically weak margins of the WR microcontinent. The combination of these mechanically weak boundaries and earlier extensional events facilitated a final ridge jump into the WR–BR margin at c. 44 Ma. We demonstrate a pre‐existing history of extension in the Late Cretaceous prior to complete fragmentation in the Eocene, resolving the apparent protracted interval between emplacement and separation of the Kerguelen LIP.
