Strategies for dealing with resistance to recommendations from accident investigations

Accident investigation reports usually lead to a set of recommendations for change. These recommendations are, however, sometimes resisted for reasons such as various aspects of ethics and power. When accident investigators are aware of this, they use several strategies to overcome the resistance. This paper describes strategies for dealing with four different types of resistance to change. The strategies were derived from qualitative analysis of 25 interviews with Swedish accident investigators from seven application domains. The main contribution of the paper is a better understanding of effective strategies for achieving change associated with accident investigation.     

Changes in circulating biomarkers during a single hemodialysis session

The hemodialysis (HD) procedure induces an inflammatory response potentially contributing to cardiovascular disease. Here we investigated the acute impact of HD on circulating biomarkers. Circulating biomarkers (small solutes, middle molecular‐sized peptides, and proteins) related to inflammation, oxidative stress, and vascular calcification (VC) were measured before and after a single session of HD in 45 clinically stable patients. Concentrations were corrected for ultrafiltration‐induced hemoconcentration. Among vascular calcification‐related biomarkers, osteoprotegerin and fetuin‐A remained unchanged while fibroblast growth factor‐23 (FGF23) decreased by ?19%. Changes of FGF23 and changes of phosphate correlated (ρ = 0.61, P < 0.001). While C‐reactive protein did not change, interleukin‐6 (IL‐6) increased by 14% and pentraxin 3 (PTX3) increased by 45%. IL‐6 and PTX3 appear to be valid biomarkers of the intradialytic inflammatory response. VC‐related markers were in general not affected by the single HD session; however, the observed correlation between acute changes of FGF‐23 and phosphate during HD warrants further studies.     

Logarithmic Mean Pressure Difference—A New Concept in the Analysis of the Flow Distribution in Parallel Channels of Plate Heat Exchangers

This paper deals with a new concept of logarithmic mean pressure difference (LMPD) to find an accurate mean or true friction coefficient for variable flow in parallel flow channels of the plate heat exchangers while considering the first and the last channel pressure drops. This is analogous to the log mean temperature difference (LMTD) used for the computation of heat transfer in heat exchangers. A method has been suggested to improve the computation of mean or a newly defined “true friction factor” and the mean velocity for considerable flow variations in the channels. A comparative study has been made between the conventional average friction factor and the true mean friction factor for large parallel channels. The results have also been compared between the mean channel pressure drop and LMPD for different sizes of the channels. The analysis shows that the mean channel pressure drop of parallel channels can be predicted accurately by using the so-called true mean friction factor rather than the average friction factor. Using the LMPD method, one can find the last channel pressure drop by knowing the first channel pressure drop of the plate package. Hence, the nature of flow distribution in parallel channels can be predicted easily.     

A two‐step method for the synthesis of a hydrophilic PDMS interpenetrating polymer network

A hydrophilic PDMS (polydimethylsiloxane) surface was formed by the synthesis of an interpenetrating polymer network (IPN) in a two‐step process. In the first step, PDMS was loaded with crosslinker and initiator using a solvent that swells the PDMS. In the second step, the PDMS sample was submerged into a solution containing the hydrophilic monomer followed by a UV‐polymerization step. The choice of solvent in the second step is critical to obtain a hydrophilic surface. It can be concluded that the solubility parameter of the solvent should be above a threshold value. Hence, in the second step only sufficiently polar solvents will result in hydrophilic PDMS‐IPNs. These principles are illustrated by using N‐vinyl‐2‐pyrrolidone as the hydrophilic monomer forming PVP/PDMS‐IPNs. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008.     

Separation of Lipid Classes by HPLC on a Cyanopropyl Column

A new method for the separation and identification of lipid classes by normal-phase HPLC on a cyanopropyl column is described. The use of a simple binary gradient, with toluene as a component, provided a rapid separation of non-polar as well as phospholipid classes. The inherent small differences in performances between possible non-polar eluent components of the gradient, such as hexane, heptane, and iso-octane, had a pronounced impact on retention times for individual phospholipid classes. Separation of molecular species within a lipid class could also be observed.     

Flow mixing inside a control-rod guide tube – Experimental tests and CFD simulations

This paper covers a combined experimental and computational effort carried out at Vattenfall Research & Development AB in order to study the thermal mixing in the annular region between a top tube and a control-rod stem. The low frequency thermal fluctuations in this region can result in problems with thermal fatigue and have caused cracks in the control-rod stems of several nuclear reactors ( [Kobayashi et al., 2009] and [0070] ).The flow in the vertical annular region formed by the top tube and the control-rod stem is characterized by the mixing of hot bypass flow with cold crud-removal flow. The crud-removal flow is flowing upwards along the control-rod stem, and the warmer bypass flow is entering through eight horizontal holes positioned in the lower part of the guide tube and four holes in the upper part of the top tube, forming jets.Two full-scale models of a control rod, including the control-rod stem and the guide tube, were constructed. The first model, designed to work at atmospheric conditions, was made of Plexiglass, in order to be able to visualize the mixing process, whereas the second one was made of steel to allow for a higher temperature difference between the two flows, and the heating of the top tube.CFD simulations of the case at atmospheric conditions were also carried out.Both the experiments and the simulations showed that the mixing region between the cold crud-removal flow and the warm bypass flow is dominated by large flow structures coming from above. The process is characterized by low frequency, high amplitude temperature fluctuations. The process is basically hydrodynamic, caused by the downward transport of flow structures originated at the upper bypass inlets. The damping thermal effects through buoyancy is of secondary importance, as also the scaling analysis shows, however a slight damping of the temperature fluctuations can be seen due to natural convection due to a pre-heating of the cold crud-removal flow. The comparison between numerical and experimental results shows a rather good agreement, indicating that experiments with plant conditions are not necessary since, through the existing scaling laws and CFD calculations, the obtained results may be extrapolated to plant conditions.The problem of conjugate heat transfer has not yet been addressed experimentally since complex and difficult measurements of the heat transfer have to be carried out. These types of measurements, along with corresponding CFD calculations, constitute one of the main challenges to be dealt with in ongoing work.     

Glutathione Conjugation and DANN Adduct Formation of Diol Epoxides in V79 Cells Expressing Human Glutathione Transferase P1-1

V79 cells and cells over-expressing glutathione transferase (GST) P1-1 have been incubated with the (+)- and (?)-anti?enantiomers of trans?7,8-dihydroxy-9,10-epoxy- 7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE) and trans?9,10-dihydroxy-11,12-epoxy-9,10,11,12-tetrahydrobenzo[c]chrysene (BCDE) and the formation of glutathione (GSH) conjugates and DNA adducts monitored. With (+)-anti?BPDE and (?)-anti?BCDE, the results demonstrate a several fold increase in conjugate formation concomitant with reduced levels of DNA adducts in GST expressing cells relative to control cells. Thus, the effects were restricted to the enantiomers with R?absolute configuration at the benzylic oxirane carbon. The rate of conjugate formation of BCDE relative to BPDE is significantly lower indicating reduced accessibility of the more lipophilic BCDE for GSTP1-1.     

Conflicts between Perception and Reality in the Management of Alien Species in Forest Ecosystems: A Norwegian Case Study

The vegetation dynamics and landscape management during 20 years of a temperate deciduous forest protected as a nature reserve in western Norway are analysed. Sycamore (Acer pseudoplatanus), an alien species in northern Europe, has become abundant in parts of the forest and the paper discusses how nature management has formulated and interpreted the introduction of sycamore. Scientists and nature managers regard the species as aggressive and a threat to the local natural biodiversity, but in this respect empirical evidence has been replaced by assumption and prejudice, and this is critically reviewed in the paper. The development of the forest has been monitored annually since 1988 and the long-term forest dynamics and behaviour of sycamore are discussed in relation to the attitudes of nature managers. The views held by nature managers are based on their own values and ideas regarding what is valuable nature, and alien species are often assumed to be invasive and aggressive, yet with no reference being made to site ecology and human local history. As an alternative to an a priori understanding of the role of alien species, the paper suggests that proper knowledge of ecosystem dynamics can only be achieved through analysis of ecological variation in space and time. The management of any species should not be according to its status as native or alien, but according to a judgment of its role and long-term behaviour. The values of nature conservationists should not be confused with the intrinsic values of nature.     

Building and exports

The building recession in many western industrialised countries has obliged their construction industries to look abroad for new markets. A Swedish view of this situation and the scope for consultancy work overseas is given here by a partner in civil engineering consultants Kjessler and Mannerstråle, AB, of Stockholm.

Most recent estimates, incidentally, put the annual value of such Swedish construction consultancy work abroad as £50-£60 million, about 60 per cent of it in the Middle East.     

Time-synchronised hardware-in-the-loop simulation — Applied to sheet-metal press line optimisation

This paper presents an off-line process parameter tuning method, focussing on complex control functions for automated manufacturing systems. The proposed method is based on a combination of simulation-based optimisation and time-synchronised hardware-in-the-loop simulation. Real industrial control systems, e.g., PLCs, are included in the simulation, executing the unchanged control code from the manufacturing plant. This approach allows all plant control functions to be included, even time-critical feedback loops and vendor secret blocks such as motion control. Consequently, the method suggested manages the problems identified in previously presented simulation-based approaches. Furthermore, a case study of an automotive sheet-metal press line has been performed to verify the proposed method, with successful results.