Variation of tow force with velocity during offshore ploughing in granular materials

Pipeline plough behaviour has been investigated by means of reduced scale physical model testing. A testing programme was devised to investigate the influence of permeability, relative density, and plough depth on the associated tow force measured during ploughing over a range of velocities in saturated granular material. An increase in tow force with velocity was found during all of the tests and the results have been compared to previously developed analytical models. A new empirical equation has been developed to describe the change in tow force with velocity for a variety of model siliceous sand conditions. Application of this new approach to full-scale ploughing requires consideration of scaling effects and the use of appropriate input parameters determined to replicate field conditions. </jats:p

The influence of incorporating a forecutter on the performance of offshore pipeline ploughs

AbstractInstallation of offshore pipelines in the seabed can be efficiently achieved using pipeline ploughs. Increased efficiency may be achievable through incorporating a smaller forecutter in advance of the main plough share. Currently guidance is limited and conflicting as to the advantages or disadvantages of incorporating a forecutter. To investigate the effect of forecutter inclusion model tests were undertaken at 1/50th scale under laboratory conditions in sand beds prepared at different relative densities in both dry and saturated conditions. Dry sand tests were used to determine the effect of the forecutter on the static or passive components of plough tow force. The currently adopted passive pressure coefficient (Cs) did not appear to vary with relative density to the same degree as previously suggested and the forecutter increased the magnitude of the passive or static resistance to ploughing. Saturated tests were used to determine the effects of the forecutter on the rate dependant component of ploughing resistance and allow verification of a dimensionless form of rate effect representation. The forecutter acts to reduce the rate effect component of plough tow force in both fine sand (low permeability) and to a lesser extent in medium sand (higher permeability). In fine and silty sands, however, incorporating a forecutter would seem highly beneficial at all ploughing depths and soil densities but in medium sand (higher permeability) the benefits of incorporation are limited to an operating window at shallower trench depths and lower relative density

The Report of the Evaluation of Fitness For Practice Pre-Registration Nursing and Midwifery Curricula Project

1.1 Introduction The debate about the competence of newly qualified nurses and midwives has a long and contentious history. Much of this debate has not been informed by a strong evidence-base, but has often relied on anecdote, personal experience and deeply held opinion. Recently, Clark and Holmes (2007) reported findings that in England ward mangers have low expectations of newly qualified nurses, who themselves reported feeling poorly prepared for their new role. Whether this reflects an accurate picture of real competence is open to question and this potential disjuncture between judgements about competency and actual competency is at the heart of this evaluation. The wider political debate on pre-registration curricula shows little sign of disappearing with the current RCN General Secretary questioning the competence of newly qualified nurses (Snow & Harrison 2008). Such pronouncements by high-profile figures have characterised much of the debate around preregistration education since the Project 2000 curriculum. The literature outlined in this chapter will extend to exploring social cognitive theory (Bandura 1977). Many evaluations of pre-registration curricula are atheoretical and it is the intention of this evaluation to avoid such a significant limitation by explicitly locating the evaluation within a theoretical framework

Nursing and Midwifery in Scotland: Being Fit for Practice

1.1 Introduction The debate about the competence of newly qualified nurses and midwives has a long and contentious history. Much of this debate has not been informed by a strong evidence-base, but has often relied on anecdote, personal experience and deeply held opinion. Recently, Clark and Holmes (2007) reported findings that in England ward mangers have low expectations of newly qualified nurses, who themselves reported feeling poorly prepared for their new role. Whether this reflects an accurate picture of real competence is open to question and this potential disjuncture between judgements about competency and actual competency is at the heart of this evaluation. The wider political debate on pre-registration curricula shows little sign of disappearing with the current RCN General Secretary questioning the competence of newly qualified nurses (Snow & Harrison 2008). Such pronouncements by high-profile figures have characterised much of the debate around preregistration education since the Project 2000 curriculum. The literature outlined in this chapter will extend to exploring social cognitive theory (Bandura 1977). Many evaluations of pre-registration curricula are atheoretical and it is the intention of this evaluation to avoid such a significant limitation by explicitly locating the evaluation within a theoretical framework

Myeloid 12/15-LOX regulates B cell numbers and innate immune antibody levels in vivo

Background. The myeloid enzyme 12/15-lipoxygenase (LOX), which generates bioactive oxidized lipids, has been implicated in numerous inflammatory diseases, with several studies demonstrating an improvement in pathology in mice lacking the enzyme. However, the ability of 12/15-LOX to directly regulate B cell function has not been studied. Methods. The influence of 12/15-LOX on B cell phenotype and function, and IgM generation, was compared using wildtype (WT) and 12/15-LOX (Alox15-/-) deficient mice. The proliferative and functional capacity of splenic CD19+ B cells was measured in vitro in response to various toll-like receptor agonists. Results. WT and Alox15-/- displayed comparable responses. However in vivo, splenic B cell numbers were significantly elevated in Alox15-/- mice with a corresponding elevation in titres of total IgM in lung, gut and serum, and lower serum IgM directed against the 12/15-LOX product, 12-hydroxyeicosatetraenoic acid-phosphatidylethanolamine (HETE-PE). Discussion. Myeloid 12/15-LOX can regulate B cell numbers and innate immune antibody levels in vivo, potentially contributing to its ability to regulate inflammatory disease. Furthermore, the alterations seen in 12/15-LOX deficiency likely result from changes in the equilibrium of the immune system that develop from birth. Further studies in disease models are warranted to elucidate the contribution of 12/15-LOX mediated alterations in B cell numbers and innate immune antibody generation to driving inflammation in vivo