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Spectral broadening and post-compression of a high-repetition rate Yb-pumped OPA in the visible and ultraviolet
No full textWe demonstrate spectral broadening and post-compression of high-repetition-rate visible and near-UV pulses from a commercial Yb-pumped optical parametric amplifier (OPA). Second-harmonic pulses from the signal of a 515 nm-pumped OPA (350–500 nm) were broadened via self-phase modulation in a single gas-filled stretched hollow-core fiber to bandwidths supporting sub-30 fs durations. Post-compression using a prism compressor or, for the shortest pulses, chirped mirrors yielded durations as short as 15 fs. The source offers simultaneous tunability in wavelength, bandwidth (Fourier limits 70 fs to sub-10 fs), and pulse duration at repetition rates up to 33 kHz
Experimental and kinetic insights into enzymatic synthesis of phosphatidylglycerol in an oscillatory baffled reactor
No full textPhosphatidylglycerol (PG) is a valuable product across pharmaceuticals, cosmetics and food industries, the conventional phospholipase D (PLD) syntheses however require organic solvents and very long reaction times to reach 50-74% yield at millilitre scale. The novelty of this study is that we have developed a solvent-free, fully aqueous synthesis route of PG using PLD-catalysed transphosphatidylation of phosphatidylcholine (PC) with glycerol in a 250 mL oscillatory baffled reactor (OBR). By optimising temperature, PLD concentration, glycerol-to-PC ratio and mixing, we achieved 63.5% PG conversion within 20 minutes with no detectable byproduct. Time-resolved kinetic analysis has revealed a three-phase mechanism in this reaction: an initial Michaelis–Menten behaviour, followed by product inhibition and eventual enzyme deactivation. We have then developed a multi-parameter kinetic model integrating intrinsic enzyme kinetics with operational variables, enabling quantitative predictions of reaction concentration, conversion and selectivity at high confidence level (R2>0.95). Coupling the green, solvent-free process with reactor intensification and mechanistic modelling establishes a scalable framework for PG manufacture and offers regulatory and sustainability advantages by avoiding volatile organic solvents and simplifying downstream processing
The Effect of Sewer-Derived Airflows on Air Pressure Dynamics in Building Drainage Systems
No full textThe performance of a building drainage system, “BDS”, is determined by the complexity of internal airflow and pressure dynamics, governed by unsteady wastewater flows from randomly discharging appliances such as WCs, sinks, and baths. Designers attempt to optimise system safety by equalising pressure and incorporating ventilation pipes and active devices such as AAVs and positive pressure reduction devices (PPRDs). However, failures within these systems can lead to foul gases and potentially hazardous microbes entering habitable spaces and posing a risk to public health. This study, for the first time, develops a novel model that simulates the effect of air from the sewer on BDS performance, which describes the correlation between system airflow and air pressure under the influence of air from the sewer. A combination of full-scale laboratory experiments representing a 3-storey building and real-world data from a 32-storey test rig configured as a building demonstrated that sewer air significantly modifies airflow and air pressure within a BDS. These findings are crucial for modern urban environments, where the prevalence of tall buildings amplifies the risks associated with air pressure transients. This work paves the way for updating codes to more effectively address real-world challenges
Good practices of artificial intelligence in biosystems engineering research
No full textThe use and integration of Artificial Intelligence (AI) and machine learning technologies into biosystems engineering create unprecedented opportunities for modelling, optimisation, and decision support across agriculture, livestock, food systems, environmental management, and related domains. However, the increasing complexity and often opacity of these methods is raising concerns regarding scientific rigour, reproducibility, transparency, generalisation and ethical responsibility. This letter establishes a set of good practice principles for authors submitting AI-driven research to Biosystems Engineering journal. The guidelines outline essential requirements for data quality, documentation of methodologies, experimental protocols, model selection, evaluation, interpretability, and reproduction of results. They emphasise the importance of open datasets and code availability, appropriate validation strategies, meaningful novelty, and clear evidence of relevance to the Biosystems Engineering scope
Building Dynamic Capabilities for Fashion Retailer Internationalisation
No full textThis chapter seeks to examine the role of dynamic capabilities (DCs) in fashion retail internationalisation. It explores the constantly changing global fashion retail landscape and how environmental turbulence and technological advances have made the possession of strong DCs a source of competitive advantage. The chapter is underpinned by Teece’s (2007) tripartite conceptualisation of DCs as comprising sensing, seizing and reconfiguring activities. Whilst Teece’s (2007) framework provides the basis for the chapter, it will also examine how this theory has been developed by other scholars to gain a comprehensive understanding of the significance of DCs for fashion firms operating or seeking to expand in international markets. Practical examples of how fashion brands sense and seize international opportunities and how they harness their resource base to leverage them are also provided. The chapter concludes by affirming the importance of managers and specifically, teams, in the development and maintenance of DCs within firms
On action rate admissibility criteria
No full textWe formulate new admissibility criteria for initial value problems motivated by the least action principle. These are applied to a two-dimensional Riemann initial value problem for the isentropic compressible Euler fluid flow. It is shown that the criterion prefers the 2-shock solution to solutions obtained by convex integration by Chiodaroli and Kreml or to the hybrid solutions recently constructed by Markfelder and Pellhammer
Irrigation scheduling of crops under the influence of shallow groundwater table
No full textThis study aims to develop irrigation schedules for Indian mustard, wheat, pea, and maize by evaluating root zone soil moisture dynamics under the influence of a shallow groundwater table (SGT) with capillary rise. Field-based Lysimeter experiments conducted at NIT Hamirpur, Himachal Pradesh, under sub-humid subtropical conditions were combined with a numerical model to capture soil moisture variations. The model showed strong agreement with observed data (R2 = 0.70–0.85; NSE = 0.72–0.85; MBE within ±0.05), confirming its predictive reliability. Irrigation schedules were derived for crop root zones with SGT (CRZSGT) and compared with gravity drainage (CRZGD). The number of irrigation events decreased from 6 to 4 for Indian mustard and wheat, from 8 to 6 for pea, and from 3 to 2 for maize. This resulted in water savings of 30.5%, 36.8%, 25%, and 33.3% for the respective crops. Crop yields were consistently higher under CRZSGT, with percentage increases of 8%, 12%, 10%, and 3% in Indian mustard, wheat, pea, and maize, respectively, compared to CRZGD. The findings demonstrate that incorporating SGT into irrigation scheduling can save water while sustaining or slightly enhancing crop yields, offering a practical framework for water-scarce regions
Analysis and Comparison of Natural Shear and Induced Tensile Fractures for Caprock Leakage Assessment
No full textThe comparison between laboratory-induced and subsurface fractures, and their corresponding flow is still unclear. Here, we examine three natural shear fractures and two induced tensile fractures from the same low-permeability lithology. Using high-resolution synchrotron imaging, we extracted three-dimensional fracture void geometries to analyse aperture distributions, surface roughness, and spatial correlation patterns. We then compared measured fracture transmissivities against theoretical predictions from parallel-plate models (cubic law) and direct numerical simulations (DNS) of flow to evaluate consistency and uncertainties. We find that despite differences in heterogeneity, induced tensile and natural shear fractures can generally yield similar flow in caprocks. Our comparisons further indicate that the choice of flow estimation method can introduce more uncertainty than the fracture opening mode
A mixed methods systematic review of the psychosocial and rehabilitative impact of prison technology with recommendations for practice
No full textExtant research suggests the use of technology in prisons can improve their safety, legitimacy, environment, and efficiency. Recently, mechanisms have also been described throughwhich technology may contribute to rehabilitation. However, less is known about the psychologicalprocesses that explain this outcome. Here we present a systematic review addressing this lacuna.The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) method wasapplied to search six databases (Scopus, PsycINFO, LISTA, Criminal Justice Abstracts, Web of Scienceand Academic Search) and grey literature in October 2020. Studies were included if participantswere people living in prison, the intervention was a technological innovation to support arehabilitative environment, and outcomes were psychological or behavioural. Fourteen reports ofthirteen studies met the criteria, and quality assessment checks were performed. Analysis usingmeta-aggregation identified five integrated findings. A broad range of technologies have beenintroduced to prisons. Technologies were found to positively influence the emotions, thinking,behaviour, and relationships of those living in prisons. However, technology failures weredetrimental experiences for prisoners. The findings are used to shape recommendations for howtechnology might contribute to the psychosocial and rehabilitative environment of prisons. <br/
Quantum dot emission enhancement via coupling with an epsilon-near-zero sublayer
No full textQuantum emitters operating at telecom wavelengths are essential for the advancement of quantum technologies, particularly for the development of integrated on-chip devices for quantum computing, communication, and sensing. Coupling resonant structures to an epsilon-near-zero (ENZ) environment has been shown to enhance their optical performance by both increasing spontaneous emission rates and improving emission directionality. In this work, we comparatively study the emission characteristics of colloidal PbS/CdS (core/shell) quantum dots at telecom wavelengths on different substrates. Two different sets of quantum dots, emitting within and outside the epsilon-near-zero region, are deposited on both glass and indium tin oxide (ITO) substrates. Our results demonstrate that coupling quantum dots to the ENZ spectral region results in a reduction in photoluminescence lifetime of 54 times, a 7.5-fold increase in saturation intensity, and a relative emission cone narrowing from 17.6° to 10.3°. These results underline the strong dependence of quantum dot emission properties on the spectral overlap with the epsilon-near-zero condition, highlighting the potential of transparent conducting oxides, such as ITO, for integration into next-generation quantum photonic devices. Owing to their CMOS compatibility, fabrication tunability, and high thermal and optical damage thresholds, these ENZ materials offer a robust platform for scalable and high-performance quantum optical systems operating within the telecom bandwidth
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