Ultrasound-induced emulsification of subcritical carbon dioxide/water with and without surfactant as a strategy for enhanced mass transport

Pulsed ultrasound was used to disperse a biphasic mixture of CO2/H2O in a 1 dm3 high-pressure reactor at 30 °C/80 bar. A view cell positioned in-line with the sonic vessel allowed observation of a turbid emulsion which lasted approximately 30 min after ceasing sonication. Within the ultrasound reactor, simultaneous CO2-continuous and H2O-continuous environments were identified. The hydrolysis of benzoyl chloride was employed to show that at similar power intensities, comparable initial rates (1.6 ± 0.3 × 10–3 s–1 at 95 W cm–2) were obtained with those reported for a 87 cm3 reactor (1.8 ± 0.2 × 10–3 s–1 at 105 W cm–2), demonstrating the conservation of the physical effects of ultrasound in high-pressure systems (emulsification induced by the action of acoustic forces near an interface). A comparison of benzoyl chloride hydrolysis rates and benzaldehyde mass transport relative to the non-sonicated, ‘silent’ cases confirmed that the application of ultrasound achieved reaction rates which were over 200 times faster, by reducing the mass transport resistance between CO2 and H2O. The versatility of the system was further demonstrated by ultrasound-induced hydrolysis in the presence of the polysorbate surfactant, Tween, which formed a more uniform CO2/H2O emulsion that significantly increased benzoyl chloride hydrolysis rates. Finally, pulse rate was employed as a means of slowing down the rate of hydrolysis, further illustrating how ultrasound can be used as a valuable tool for controlling reactions in CO2/H2O solvent mixtures

CO2 assisted blending of poly(lactic acid) and poly(ε-caprolactone)

Poly(lactic acid) (PLA) is gaining increasing interest from the packaging industry as a biodegradable alternative to oil based polymers such as polypropylene (PP) and polyethylene terephthalate (PET). However, its’ inherent brittle nature prevents widescale commercial use. Blending in order to improve the Young’s modulus, yield stress and elongation to break, provides a possible alternative although many polymers have been found to be immiscible with PLA. In this study, high pressure carbon dioxide (CO2) was utilised during blending to encourage miscibility between two normally immiscible polymers: poly(ε-caprolactone) (PCL) and poly(lactic acid) (PLA). Blends were prepared by melt blending in the presence of carbon dioxide (CO2) and compared to solvent casting and melt blending with a single-screw extruder. CO2 assisted blends demonstrated a significant reduction in the size and number of PCL domains in a PLA matrix, and consequently improved the adhesion between phases at the microscale. The optimum melt blend composition for Young’s modulus, yield stress and elongation to break was found to be 75% PLA and 25% PCL. Mechanical properties of PLA 2002D blends were further improved when prepared by CO2 assisted melt blending

Destabilising conventions : characterising the cost

Conventions are often used in multi-agent systems to achieve coordination amongst agents without creating additional system requirements. Encouraging the emergence of robust conventions via fixed strategy agents is one of the main methods of manipulating how conventions emerge. In this paper we demonstrate that fixed strategy agents can also be used to destabilise and remove established conventions. We examine the minimum level of intervention required to cause destabilisation, and explore the effect of different pricing mechanisms on the cost of interventions. We show that there is an inverse relationship between cost and the number of fixed strategy agents used. Finally, we investigate the effectiveness of placing fixed strategy agents by their cost, for different pricing mechanisms, as a mechanism for causing destabilisation. We show that doing so produces comparable results to placing by known metrics

Ultrasound-induced CO₂ /H₂O emulsions as a medium for clean product formation and separation : the Barbier reaction as a synthetic example

: Subcritical CO2/H2O (30 °C/80 bar) was employed as a renewable solvent mixture in a 1 dm3 ultrasound reactor. As a representative synthetic transformation, the metal-mediated Barbier allylation was used to demonstrate the facility of formation and separation of the homoallylic alcohol product. The chemoselectivity over the competing aldehyde reduction could be improved by deploying the biocompatible nonionic surfactant Tween 80, a saturated salt aqueous phase, or by carrying out the reaction at 60 °C/120 bar. All of these modifications led to an apparent rate increase in the desired allylation. A range of substituted benzaldehydes afforded the corresponding homoallylic alcohols in moderate to high yields. The presence of water constituted a necessary condition for efficient product formation, while CO2 provided an appropriate phase for clean product separation by exploiting a favorable homoallylic alcohol enrichment. In this way, 0.025 mol of homoallylic alcohol product could be isolated from the CO2 phase in 1 h, avoiding further extraction stages that would typically require organic solvents

A Review of The Valorisation and Management of Industrial Spent Catalyst Waste in The Context of Sustainable Practice: The Case of The State of Kuwait in Parallel to European Industry

Industrial solid waste management encompasses a vital part of developed and developing countries strategies alike. It manages waste generated from vital industries and governs the hazardous waste generated as a major component of integrated waste management strategies. This communication reviews the practices that govern the management approaches utilised in the developed world for industrial spent catalysts. It critically assess the current situation of waste management within the developing world region focusing on the industrial waste component, in a novel attempt to crucially develop a way forward strategy based on best practices and future directions with major European industries. The review also draws parallels with European countries to compare their practices with those of the State of Kuwait, which rely solely on landfilling for the management of its industrial waste. Spent catalysts recovery methods are discussed in length covering conventional methods of valuable metals and chemicals recovery (e.g. hydrometallurgical, solid/liquid and liquid-liquid extraction) as well as biological recovery methods. A major gap exists within regulations that govern the practice of managing industrial waste in Kuwait, where it is essential to start regulating industries that generate spent catalysts in-view of encouraging the establishment of valorisation industries for metal and chemical recovery. This will also create a sustainable practice within state borders, and can reduce the environmental impact of landfilling such waste in Kuwait

An Examination of Celtic Craft and the Creative Consciousness as a Contribution to Marketing Creativity

Examination of the Celtic craft sector identifies a creative form of marketing which has its foundations in imagination, intuition and innovation, rather than the linear prescriptions of formal marketing frameworks and language which still dominate contemporary marketing management texts. The creative marketing competencies identified in the sector are also grounded within a wider creative marketing paradigm where experimental forms of marketing are encouraged, postmodern ideals are embraced and artistic philosophy and practice encouraged. The controlled Saxon influenced Marketing Establishment is challenged by the freer, more creative fringe of Celtic marketing as the avant garde

Solutions for recycling emerging wind turbine blade waste in China are not yet effective

Wind power supply chains are evolving as markets expand to reach climate goals. With the largest installed wind power capacity globally, China must deal with increasing composite turbine waste and anticipate its associated costs. Here we predict the quantity and composition of wind turbine blade waste based on historic deployment. A high-resolution database containing 14 turbine capacities (150–5500 kilowatts) was compiled based on 104 turbine models. The environmental and financial costs of waste treatment options were evaluated using a bottom-up approach. Based on current installations and future projections, 7.7 to 23.1 million tonnes of blade waste will be generated in China by 2050. Technologies exist to recycle glass fibre from blade waste, but these solutions vary in level of maturity and are not always commercially available, cost-competitive, or environmentally sustainable. Our findings can inform decision-makers in governments and industry on the pathways to carbon neutrality