(3aR,6S,7aR)-7a-Bromo-2-methyl­sulfonyl-1,2,3,6,7,7a-hexa­hydro-3a,6-ep­oxy­isoindole

In the title compound, C9H12BrNO3S, the two tetra­hydro­furan rings adopt envelope conformations, the pyrrolidine ring adopts a half-chair conformation and the six-membered ring is in a boat conformation. In the crystal, weak inter­molecular C—H⋯O hydrogen bonds link the mol­ecules into R 2 2(8) and R 2 2(14) rings along the b-axis direction

Steric acceleration of some pericyclic reactions.

Steric effects are important in synthesis. Whilst steric hindrance is well known in hindering reactions, steric effects can also be employed to accelerate reactions, in particular cycloaddition reactions, and even to promote reactions that otherwise do not occur. A survey is included in previous work on steric effects in chemical reactions, principally cycloadditions. This includes a brief discussion on the importance of orientation and solvent effects on Diels-Alder cyclisations and ene reactions. The effect of substituents on the cyclisation of N-allyl furfurylamines has been studied. It was shown that bulky N-protecting groups enhance cyclisation, an effective buttress being the trityl (triphenylmethyl) group. The latter has the added advantage of being particularly easy to remove. A study of some ene reactions has also been carried out and steric acceleration of these processes has also been observed. A novel reaction involving an intermolecular cycloaddition followed by a sterically accelerated ene reaction has also been uncovered. Some attempts have also been made at carrying out these sterically accelerated reactions on a solid support as required in combinatorial chemistry. This involved the preparation of a new type of substituted support, with a view to utilising this in a combinatorial approach to synthesis. The structures have been supported by using a molecular modelling package, Alchemy 2000 from Tripos Associates Inc

AeroSandbox: Foils Design and Optimization via Automatic Differentiation

LAUREA MAGISTRALEL'obiettivo di questa ricerca è integrare un framework di analisi aerodinamica nel campo dell'architettura e ingegneria navale. Negli ultimi anni, i foil, che sono ali sommerse in acqua, hanno attirato molta attenzione per la loro capacità di migliorare le prestazioni di una barca. Di conseguenza, la conoscenza derivante dalla progettazione di aerei si è trasferita al campo dei foil, poiché entrambi i settori sono governati dagli stessi principi fisici. Allo stesso modo, il software sviluppato da Sharpe P., noto come AeroSandbox, è stato ampiamente rivisto per adattarsi all'analisi dei foil. Questo pacchetto, nato per la progettazione di aerei, è stato sfruttato per ottimizzare queste superfici grazie alla sua avanzata efficienza computazionale, in particolare la sua tecnica di differenziazione automatica. Dapprima si è deciso di semplificare la progettazione dei foil all'interno del programma accoppiandolo con un software CAD ampiamente noto. Per l'analisi idrodinamica, i solutori di media fedeltá in AeroSandbox sono stati aggiornati e potenziati. La presenza di una superficie di separazione tra aria e acqua cambia il comportamento dei foil; pertanto, l'influenza del pelo libero è stata presa in considerazione. Successivamente, si è condotto uno studio CFD per validare la maggior parte del codice implementato. Per evidenziare la versatilità di questi metodi, sono state esplorate anche diverse applicazioni nel campo aeronautico.The aim of this research is to seamlessly integrate an aerodynamic analysis framework into the field of naval architecture and engineering. In the last years, hydrofoils, which are wings submerged in water, have gained much more attention for their ability to improve the performance of a boat. Therefore, the knowledge from aircraft design has transitioned to the foiling one, as both domains are governed by the same physical principles. Similarly, the software developed by Sharpe P., known as AeroSandbox, has been extensively revised to cater to hydrofoil analysis. This package, born to design aircraft, was harnessed to optimize these surfaces thanks to its advanced computational efficiency, particularly its automatic differentiation technique. To simplify the design of the hydrofoils within the program, it has been coupled with a widely-used CAD software. For hydrodynamic analysis purposes, the existing mid-fidelity tools in AeroSandbox were updated and upgraded. The presence of a boundary surface between air and water changes the hydrofoils characteristics; therefore, the influence of the free surface has been taken into account. Subsequently, a high-fidelity CFD study has been carried out to validate the majority of the implemented code. To highlight the versatility of these enhanced methods, also several aeronautical applications were explored

Can social enterprises remain sustainable and mission-focused? Applying resiliency theory

Purpose– The purpose of this paper is to adapt concepts from resiliency theory to understand the conditions under which social enterprises may remain true to form and purpose or are likely to change their character. This leads us to consider issues of governance, economic incentives associated with different organizational forms of social enterprise and the effects of the financial environment, the role of organizational slack and the influence of organizational leadership on the dynamics of social enterprises. Three case studies of organizations in the USA are analyzed to illustrate the application of resiliency theory to the stability of social enterprises. The fact that all forms of social enterprise must reconcile the tensions of social purpose and market raises important questions about the dynamics of these enterprises.Design/methodology/approach– Theory and case study analysis.Findings– Governance, financial incentive structure, organizational slack and leadership influence the stability of social enterprises.Originality/value– First application of resiliency theory to the analysis of social enterprise stability.</jats:sec