Determination of the heat transfer coefficient at the metal–die interface for high pressure die cast AlSi9Cu3Fe

When simulating the High Pressure Die Casting ‘HPDC’ process, the heat transfer coefficient ‘HTC’ between the casting and the die is critical to accurately predict the quality of the casting. To determine the HTC at the metal–die interface a production die for an automotive engine bearing beam, Die 1, was instrumented with type K thermocouples. A Magmasoft® simulation model was generated with virtual thermocouple points placed in the same location as the production die. The temperature traces from the simulation model were compared to the instrumentation results. Using the default simulation HTC for the metal–die interface, a poor correlation was seen, with the temperature response being much less for the simulation model. Because of this, the HTC at the metal–die interface was modified in order to get a better fit. After many simulation iterations, a good fit was established using a peak HTC of 42,000 W/m2 K, this modified HTC was further validated by a second instrumented production die, proving that the modified HTC gives good correlation to the instrumentation trials. The updated HTC properties for the simulation model will improve the predictive capabilities of the casting simulation software and better predict casting defects.

3D Analysis of Heat Transfer Intensification by Re-Entrance Flow Pin-Fins Microstructures with a Highly Thermal-Conductive Plate

Joule heat-induced hot-spot formation sets severe limits in the operation of continuous annular electrochromatography (CAEC), a new concept for preparative separation as an analog to analytical capillary electrochromatography (CEC). This may lead to eluent flow perturbance, even to boiling, which would massively weaken separation efficiency and may even hamper the stationary phase used for separation. For reasons of system integration and high-efficiency heat transfer, micro flow heat exchangers are considered with a separate coolant flow. A 3D numerical analysis of the heat transfer of water single-phase laminar flow in a square microchannel and different arrays of micro pin-fins was carried out using COMSOL Multiphysics. Several advanced materials with low electric conductivity and at the same time with high heat conductivity were put forward to be used in the CAEC system. As essential design point, it is proposed to constitute the micro heat exchanger from two different parts of the CAEC system, namely a microstructured pin-fins plate and a so-called conductive plate.

Psychological distress among survivors of esophageal cancer: the role of illness cognitions and coping

Leventhal's common sense model has provided a useful framework for explaining psychological distress in several chronic illnesses. The model indicates that a person's perception of their illness and their coping strategies are the key determinants of their experience of psychological distress. The present research examines whether illness perceptions and coping strategies are related to levels of psychological distress among survivors of esophageal cancer. Everyone registered with the Oesophageal Patients' Association in the UK was mailed a questionnaire booklet, which included the Illness Perception Questionnaire-Revised, the Cancer Coping Questionnaire, and the Hospital Anxiety and Depression Scale. Complete responses were received from 484 people. Regression models indicated that the variables measured could explain 51% of the variance in anxiety and 42% of the variance in depression. Perceptions of esophageal cancer explained the majority of this variance. Positive focus coping strategies were also found to be important in explaining psychological distress. The results of this study are consistent with previous research demonstrating that illness perceptions are stronger correlates of adaptive outcomes than coping strategies. The findings suggest that cognition-based interventions could potentially be most effective in minimizing emotional distress among survivors of esophageal cancer.

The factor structure of the revised Illness Perceptions Questionnaire in a population of oesophageal cancer survivors

Objectives
To determine whether the proposed 7-factor structure of the Illness Perception Questionnaire-Revised (Timeline Acute/Chronic, Timeline Cyclical, Consequences, Personal Control, Treatment Control, Illness Coherence and Emotional Representations) is appropriate among a population of oesophageal cancer survivors.
Methods
Everyone registered with the Oesophageal Patients’ Association in the UK (n=2185) was mailed a questionnaire booklet which included the Illness Perception Questionnaire-Revised. Responses from 587 oesophageal cancer survivors (27%) were subjected to a confirmatory factor analysis.
Results
The proposed 7 factor structure provided a reasonable fit of the data. Modification indices suggested that a significantly better fit could be provided if one of the items on the Timeline Acute/Chronic factor loaded on the Treatment Control factor and an error covariance was added between 2 other items on the Timeline Acute/Chronic factor.
Conclusions
The model fit for the 7 factor structure proposed by Moss-Morris et al. (2002) was found to be adequate in our study. However, the structure of the timeline acute/chronic factor needs to be considered, particularly when the IPQ-R is to be used among older people with a potentially life-threatening illness or those receiving palliative care.

Volumetric Properties, Viscosities, and Isobaric Heat Capacities of Imidazolium Octanoate Protic Ionic Liquid in Molecular Solvents

Densities (F), viscosities (?), and isobaric heat molar capacities (Cp) of binary mixtures containing imidazolium octanoate, [Im][C7CO2], a protic ionic liquid (PIL), with four molecular solvents, water, acetonitrile, ethanol, and 1-octanol, are determined as a function of temperature from (298.15 to 323.15) K and within the whole composition range at atmospheric pressure. Excess molar volumes, VE, excess molar heat capacities, Cp E, and the deviation from additivity rules of viscosities, ??, of imidazolium octanoate solutions were then deduced from the experimental results, as well as apparent molar volumes, Vfi, and partial molar volumes, V j m,i. Results are discussed according to the nature of the interaction between the PIL and the molecules and the effect of temperature. The excess Gibbs energies of activation of viscous flow (?G*E) for these systems were then calculated at 298.15 K. The excess isobaric heat capacities, Cp E, of binary ([Im][C7CO2] + solvent) systems, depend also of the nature of the molecular solvent in mixture. The excess properties were then correlated, at each temperature, as a function of composition by a Redlich-Kister-type equation. Finally results have been discussed in terms of molecular interactions and molecular structures in these binary mixtures, and thermodynamic properties of investigated binary mixtures were then compared to literature values together to investigate the impact of the nature of the solvent on these reported properties.

Short Isoforms of the Cold Receptor TRPM8 Inhibit Channel Gating by Mimicking Heat Action Rather than Chemical Inhibitors

Transient receptor potential (TRP) channels couple various environmental factors to changes in membrane potential, calcium influx, and cell signaling. They also integrate multiple stimuli through their typically polymodal activation. Thus, although the TRPM8 channel has been extensively investigated as the major neuronal cold sensor, it is also regulated by various chemicals, as well as by several short channel isoforms. Mechanistic understanding of such complex regulation is facilitated by quantitative single-channel analysis. We have recently proposed a single-channel mechanism of TRPM8 regulation by voltage and temperature. Using this gating mechanism, we now investigate TRPM8 inhibition in cell-attached patches using HEK293 cells expressing TRPM8 alone or coexpressed with its short sM8-6 isoform. This is compared with inhibition by the chemicals N-(4-tert-butylphenyl)-4-(3-chloropyridin-2-yl)piperazine-1-carboxamide (BCTC) and clotrimazole or by elevated temperature. We found that within the seven-state single-channel gating mechanism, inhibition of TRPM8 by short sM8-6 isoforms closely resembles inhibition by increased temperature. In contrast, inhibition by BCTC and that by clotrimazole share a different set of common features. © 2012 by The American Society for Biochemistry and Molecular Biology, Inc.