A comparative study of Inconel 625 laser cladding by wire and powder feedstock

It has been established that laser cladding technique is useful for enhancing surface performances, hence extending the life of many components in severe corrosive-wear environments. However, a comparative study of the surface performances of laser coatings made via powder and wire feeding systems has not been performed. Inconel 625 powder and wire were deposited on the AISI 304 substrate using similar processing parameters. The microstructure, together with the depth of substrate penetration and the degree of dilution of the deposited tracks, was examined using an optical microscope and a scanning electron microscope (equipped with an energy-dispersive spectrometer). The micro-hardness was measured using a Vickers hardness tester. At optimized parameters, laser tracks of Inconel 625 wire and powder had a strong metallurgical bond at the track–substrate interface and no crack and pore were deposited. Due to the higher laser beam infiltration and a larger depth of substrate penetration, higher substrate dilution was observed in the powder-fed tracks. The tracks comprise continuous ?-matrix and secondary compounds (rich in Nb and Mb). However, finer dendritic microstructure and higher number density of inter-dendritic precipitates were observed in a typical powder laser track compared with the corresponding wire laser track. The typical powder laser track demonstrated higher hardness (245 HV_0.3) compared with the corresponding wire laser track (224 HV_0.3).     

Ethnic Minority Groups and the Design of Public Open Space: An inclusive landscape?

People from ethnic minority groups have a range of experiences of living in Britain, some of which are significantly different from those of white British people. Previous research and case studies suggest that the physical environment has a positive or negative role in perceptions of everyday life. It is argued that landscapes have a symbolic dimension, and aspects of landscapes can be recognized as familiar or alien, welcoming or excluding. A wide variety of case studies in Britain are used to discuss design and management practices that reflect a range of cultural experiences. The need for landscape architects and managers to be aware of how places may be interpreted in different ways by different ethnic minority groups, and to work towards inclusive design, is highlighted.     

Negative Cooperativity in NAD(P)H Quinone Oxidoreductase 1 (NQO1)

NAD(P)H quinone oxidoreductase-1 (NQO1) is a homodimeric protein that acts as a detoxifying enzyme or as a chaperone protein. Dicourmarol interacts with NQO1 at the NAD(P)H binding site and can both inhibit enzyme activity and modulate the interaction of NQO1 with other proteins. We show that the binding of dicoumarol and related compounds to NQO1 generates negative cooperativity between the monomers. This does not occur in the presence of the reducing cofactor, NAD(P)H, alone. Alteration of Gly150 (but not Gly149 or Gly174) abolished the dicoumarol-induced negative cooperativity. Analysis of the dynamics of NQO1 with the Gaussian network model indicates a high degree of collective motion by monomers and domains within NQO1. Ligand binding is predicted to alter NQO1 dynamics both proximal to the ligand binding site and remotely, close to the second binding site. Thus, drug-induced modulation of protein motion might contribute to the biological effects of putative inhibitors of NQO1.     

A molecular dynamics study of the Gibbs free energy of solvation of fullerene particles in octanol and water

The Gibbs free energy of solvation (ΔG^solv) for C₆₀, and six other idealized, non-functionalized, fullerene particles of differing size and shape has been determined in octanol and water solvents from molecular dynamics simulations using thermodynamic integration. In particular, we have studied Buckminster fullerene (C₆₀) and open and capped carbon nanotubes of different aspect ratios and solvent accessible surface areas. Knowledge of the ΔG^solv of a molecule in octanol and water can be used to understand the partitioning of the molecule between organic and aqueous phases and is one of several parameters used to model the fate of chemicals in the natural environment. The simulations were performed at ambient conditions, i.e., a temperature of 25 °C and a pressure of 1 bar. The fullerene molecules are all found to have a very high ΔG^solv in water, and a very low ΔG^solv in octanol, suggesting a strong preference for the organic phase. From a comparison of the results for capped and uncapped carbon nanotubes we found that the uncapped tubes exhibit significantly higher ΔG^solv than capped tubes. Furthermore, for capped carbon nanotubes, hydrophobic/organophilic shifts are observed with increasing excluded volume and solvent accessible surface area.     

Stability of sunflower 2S albumins and LTP to physiologically relevant in vitro gastrointestinal digestion

In order for a protein to elicit a systemic allergic response it must reach the circulatory system through the intestinal mucosa as a sufficiently large fragment with adequate structural integrity. Sunflower LTP and 2S albumins (SFA8 and three mixed fractions of Alb1 and Alb2) were digested in simulated gastric fluid (SGF) for 2 h and the conditions were then changed to mimic the intestinal environment for a further 2 h digestion. The effects of phosphatidylcholine (PC) and emulsification on the digestibility of the proteins were investigated. PC protected all of the proteins studied against both gastric and intestinal digestive enzymes but to different extents. Emulsification of SFA8 resulted in strong protection against digestion, which was further enhanced by the presence of PC in the SGF. These results highlight the importance of considering real food structures such as emulsified systems and also the gastrointestinal environment that proteins are exposed to once consumed when assessing allergenicity.     

A study of the physicochemical and sensory properties of organic and conventional potatoes (Solanum tuberosum) before and after baking

The objective of this study was to investigate if there were any differences in the physicochemical and sensory properties of organic and conventional potatoes (cv. Orla). The conventional potatoes had a lower dry matter content (P ≤ 0.05) and a slightly softer texture (P ≤ 0.05) than the organic potatoes. The trained panel perceived the conventional baked potato to be slightly softer, less adhesive and wetter than the organic baked potato (P ≤ 0.05). However, the consumer panel found no significant difference between the organic and conventional baked potato samples for the sensory attributes of appearance, aroma, texture and taste acceptability.     

Investigating Local Structure in Layered Double Hydroxides with 17O NMR Spectroscopy

A new method based on the “memory effect” for efficient and economical ¹⁷O labeling of layered double hydroxides (LDHs) is introduced. High‐quality ¹⁷O solid‐state NMR spectra are obtained, for the first time, for LDHs prepared with only several hundred microliters of ¹⁷O‐enriched H₂O. The ¹⁷O resonances due to the different oxygen ions in the structure of LDHs can be resolved with better resolution than the results obtained from ¹H ultrafast magic angle spinning (MAS) NMR spectroscopy. The results show clear evidence for Al–O–Al avoidance. Since only intermediate MAS speeds and fields are used, this new approach can be incorporated easily with a variety of dipolar recoupling schemes to explore the key interactions and applications of LDHs.     

Implementing the requirements of the Water Framework Directive for rural water supply schemes in Scotland

In a project pioneering the implementation of the European Union Water Framework Directive in Scotland, a programme of local stream flow gauging in Lochaber demonstrated that low flow yields in the sources were greater than predicted by standard methodologies for ungauged catchments in the UK. This meant that the abstraction required for the water treatment works represented an acceptable proportion of the yield, and complied with Scottish Environment Protection Agency guidance for maintaining good ecological status in the catchments. Development of new sources with dams, pumping stations and pipelines was avoided, thus reducing costs and environmental impacts. A programme of stakeholder consultations was carried out throughout the Water Order application process and agreement on proposed abstractions was reached with over 20 stakeholders.     

Emotional and motivational changes after bilateral lesions of the globus pallidus.

This study investigated motivational changes in a 44 year-old man (PJ) who developed considerable reduction in spontaneous activity and speech, flat affect, social withdrawal, loss of interest, inability to "feel," and lack of concern regarding his medical condition after bilateral, focal, anoxic lesions of the globus pallidus. PJ and 30 male controls performed a task designed to parse hedonic evaluation, or liking, from incentive motivation, or wanting. Affective stimuli were presented on a computer screen and subjects controlled viewing time by pressing keys. PJ's liking and wanting of unpleasant stimuli was similar to that of controls. In response to pleasant stimuli, PJ showed normal ratings of wanting and hedonic appreciation, but significantly reduced viewing time or made no responses. Active withdrawal from liked stimuli could constitute the basic mechanism underlying poor motivation and social withdrawal associated with globus pallidus damage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis and photophysical properties of meso‐aminophenyl‐substituted heptamethine dyes as potential leads to new contrast agents

The series of rigid meso‐aminophenyl‐substituted heptamethine dyes presented herein exhibit surprising fluorescence properties, demonstrating larger Stokes shifts when compared with both structurally similar rigid meso‐chlorophenyl and linear heptamethine dyes. Based on their photophysical properties, these are of considerable importance to the development of contrast agents, within biology and medicine.