University of Queensland

Large language models (LLMs) are increasingly deployed in politically sensitive contexts, raising concerns about their susceptibility to ideological biases. In this work, we examine how synthetic persona conditioning shapes ideological expression across seven open-weight instruction-tuned models (7B–72B parameters) using the Political Compass Test (62 statements) as a standardized behavioral probe. Across three studies involving 200,000 synthetic personas and more than 260 million model responses, we analyze implicit and explicit malleability, as well as theme-associated variation. We find that: (i) larger models exhibit broader implicit ideological coverage, increasing from 14%–35% for 7–8B models to up to 49% for 70B+ models; (ii) explicit ideological priming induces large and statistically significant shifts, with right-authoritarian cues moving all models in the intended direction and generally producing larger shifts than left-libertarian cues across model-axis comparisons; (iii) left-libertarian priming produces more heterogeneous responses, with counter-directional economic shifts in three of four 7–8B models and intended-direction shifts across all 70B+ models; and (iv) theme-associated semantic content in persona descriptions is linked to systematic and interpretable directional shifts in ideological space. While our results identify an upstream mechanism through which persona conditioning can alter model responses under a standardized ideological probe, we do not test whether such shifts affect users’ beliefs, decisions, or political behavior. Our findings are best understood as evidence of ideological malleability at the generation layer, highlighting the need to account for interactional factors when evaluating political neutrality, fairness, and safety in English-prompted, persona-conditioned language models.

The fast uptake of distributed energy resources (DERs) presents increasing challenges for managing hosting capacity in distribution networks. Existing solutions include direct load control, operating envelopes, and price-based control through dynamic energy prices. Despite their effectiveness, these methods often rely on assumed prosumer behavioural patterns and overlook prosumers' desire to retain control over their devices. Additionally, current fixed or Time-of-Use (ToU) prices are based on spatial and temporal averages, having limited impact on network conditions and DER operation. To address these limitations, this paper proposes a bilevel optimisation framework that explicitly models prosumer decision-making in the design of dynamic network prices. The upper level represents the distribution system operator (DSO), setting network prices under cost-recovery and network constraints, while the lower level models prosumers optimising DER operation in response. The proposed framework preserves customer prerogative, enhances DER flexibility, and offers actionable insights for network hosting capacity management and the evolution of network tariff structures under high DER penetration.

The incorporation of biomass-derived char into coking coal is attracting increasing interest as a decarbonisation strategy; however, its influence on coal behaviour during carbonisation and the resulting coke structure remains insufficiently understood. This study investigates the role of surface energy in coal–char interactions during pyrolysis and examines the effect of char addition on the pore structure of coke.The rheological behaviour of two Australian bituminous coals of differing rank, a medium-volatile coal (MVC) and a high-volatile coal (HVC), with vitrinite contents of 73.6 % and 77.2 %, respectively, was analysed to map their viscoelastic pathways and understand bubble evolution during pyrolysis. MVC exhibited a relatively high viscosity (>105 Pa·s) within its liquid-like state, enabling stable bubble growth before coalescence. In contrast, HVC exhibited a lower viscosity (3 × 104 Pa·s), resulting in unstable bubbles that collapsed shortly after nucleation.Surface energy measurements obtained using the film flotation method revealed that MVC possessed a surface energy of 57 mJ m⁻2 during the bubble growth stage, whereas HVC exhibited a substantially lower value of 41 mJ m⁻2. Notably, bagasse char produced at 800 °C exhibited a surface energy of 57 mJ m⁻2, matching that of MVC. Optical microscopy confirmed that approximately 95 % of this char was incorporated into MVC, compared with only 64 % incorporation in HVC. These observations suggest that surface energy matching promotes wetting and interfacial bonding between coal and char during coking.Micro-CT analysis and pore size characterisation further demonstrated that char addition substantially reduced the pore size distribution and overall porosity of both coals, resulting in denser coke structures. These findings demonstrate that surface energy compatibility and coal viscoelastic behaviour play important roles in coal–char interactions, pore development, and ultimately coke strength, thereby advancing the substitution of fossil coal with renewable carbon in ironmaking applications.

Observed differences between paddy and upland croplands in soil organic carbon (SOC) and soil inorganic carbon (SIC) may reflect environmental and data-provenance imbalances rather than land-use effects. We reconstructed independent SOC and SIC profile datasets across China, harmonized depths, and separated full-sample comparisons from a prespecified comparable subset. Among all topsoil SOC profiles retained after applying the inclusion criteria (334 paddy, 347 upland), the median Upland-minus-Paddy contrast was −2.12 g kg−1; within the shared subset (97/95), it attenuated to −0.35 g kg−1 (95% interval, −1.74 to 1.55). For 97 paddy soils, changing only the land-use indicator to upland while holding observed soil and environment states fixed yielded a mean SOC contrast of −0.58 g kg−1 (joint 95% interval, −1.02 to −0.15), with 78.4% negative. A layer-resolved Extra Trees S-learner supported this scenario with out-of-fold R2 = 0.72 and mean R2 = 0.72 across ten spatial partitions. The shared topsoil SIC subset retained only 9 paddy and 7 upland profiles, so adjusted SIC could not be estimated. Aridity index (AI) stratification showed the strongest negative SOC contrast in more humid high-AI croplands (−1.08 g kg−1; −1.62 to −0.56), whereas low- and middle-AI strata crossed zero; the high-minus-middle difference was −1.29 g kg−1 (−2.09 to −0.60). Among comparable croplands, observed topsoil SOC differed little between paddy and upland fields, but model predictions indicated lower SOC under upland land use, particularly in humid regions. These results suggest a modest SOC advantage of paddy croplands, while SIC differences remain unresolved.

Bioethanol production from lignocellulosic biomass offers a sustainable alternative to fossil fuels; however, challenges persist in pretreatment efficiency and process integration. This study presents a one-pot, microwave-assisted process for ethanol production from sugarcane bagasse using ternary deep eutectic solvents (DES), combining pretreatment, enzymatic hydrolysis, and fermentation in a single vessel. Two DES systems, Choline chloride:Ethylene glycol:Nickel chloride hexahydrate (CC:EG:Ni) and Choline chloride:Ethylene glycol:Magnesium chloride (CC:EG:Mg) were evaluated across six Australian sugarcane varieties with varying lignin and cellulose content. The results demonstrate that DES pretreatment significantly enhanced biomass digestibility, increasing average glucose content from 37.2% to 50.2% (+34.8%) and reducing total lignin from 19.5% to 10.2% (−47.6%). The highest ethanol yield (46.9 mg/g SCB) was achieved using CC:EG:Ni with the QS08-8662 variety, demonstrating the influence of genotype on process performance. Structural characterisation (SEM, FTIR, XRD) confirmed lignin disruption and increased cellulose accessibility, correlating with improved enzymatic hydrolysis. DES recyclability was demonstrated using a centrifugal vacuum concentrator, with <10% solvent loss and only a 10.8% decline in performance after two cycles. These results highlight the potential of DES-based one-pot systems as a scalable and environmentally sustainable approach for lignocellulosic ethanol production. The study underscores the importance of feedstock selection and structural traits, such as lignin content and crystallinity, in optimizing process efficiency. This genotype-resolved evaluation and solvent-recovery pathway highlight DES-enabled one-pot SSF as a promising route toward integrated, sustainable ethanol production from sugarcane residues.