Experimental and numerical analysis of the influence of cable tray arrangements on the resulting mass loss rate and fire spreading

In the context of industrial buildings and power plants, electrical installations and cable trays represent a main fuel load and a potential initial fire source due to possible short circuits or comparable malfunction. Furthermore, a fire can spread from one tray to additional trays mounted above and/or horizontally on one tray. Because of the high significance of cable fires, several research projects have been carried out, investigating the fire behaviour of cables from small‐scale tests, eg, the cone calorimeter, up to large‐scale tests, analysing complete cable tray constructions. The goal of the work presented in this paper is the extension of the knowledge regarding the influence of geometrical parameters like the packing density and tray distance on the burning behaviour and fire spread of cable tray installations. The results are considered, together with test results from the literature, to quantify the main physical parameters describing the burning behaviour. In a next step, the general applicability of these parameters as input data for the parametrization of the source term of numerical simulations is shown. The test results show that the burning behaviour and the fire spreading highly depend on the cable arrangement of the cables on the cable tray, in combination with other boundary conditions. By applying the results as input for a fire simulation, the mass loss rate is considered appropriately.     

Molten salt synthesis of MAX phases in the Ti-Al-C system

The molten salt method was used to synthesise the MAX phase compounds Ti₂AlC and Ti₃AlC₂ from elemental powders. Between 900–1000?°C, Ti₂AlC was formed alongside ancillary phases TiC and TiAl, which decreased in abundance with increasing synthesis temperature. Changing the stoichiometry and increasing the synthesis temperature to 1300?°C resulted in formation of Ti₃AlC₂ alongside Ti₂AlC and TiC. The type of salt flux used had little effect on the product formation. The reaction pathway for Ti₂AlC was determined to be the initial formation of TiC_1-x templating on the graphite and titanium aluminides.     

Capacity Efficiency and Restorability of Path Protection and Rerouting in WDM Networks Subject to Dual Failures

Resilient optical networks are predominately designed to protect against single failures of fiber links. But in larger networks, operators also see dual failures. As the capacity was planned for single failures, disconnections can occur by dual failures even if enough topological connectivity is provided. In our approach the design of the network minimizes the average loss caused by dual failures, while single failures are still fully survived. High dual failure restorability is the primary aim, capacity is optimized in a second step. For WDM networks with full wavelength conversion, we formulate mixed integer linear programming models for dedicated path protection, shared (backup) path protection, and path rerouting with and without stub-release. For larger problem instances in path rerouting, we propose two heuristics. Computational results indicate that the connectivity is of much more importance for high restorability values than the overall protection capacity. Shared protection has similar restorability levels as dedicated protection while the capacity is comparable to rerouting. Rerouting surpasses the protection mechanisms in restorability and comes close to 100% dual failure survivability. Compared to single failure planning, both shared path protection and rerouting need significantly more capacity in dual failure planning.     

Spinal abscess of Haemophilus paraphrophilus. A case report

STUDY DESIGN: A case of paraspinal abscess formation from Haemophilus paraphrophilus is presented. OBJECTIVES: To describe a case of paraspinal abscess formation from H. paraphrophilus, a fastidious commensal organism of the mouth and pharynx. A precise bacteriologic identification can be difficult; techniques for such identification are discussed. SUMMARY OF BACKGROUND DATA: Spinal abscess caused by H. paraphrophilus is unusual and can be very difficult to diagnose. METHODS: The etiology, clinical presentation, technical examinations, and treatment are reviewed. RESULTS: Prolonged antibiotic treatment was curative, although surgery was considered. CONCLUSIONS: Bacteriologic diagnoses in these rare infections are difficult. Antibiotic therapy was curative in the patient described.     

Calibrating screens for continuous colour displays

This paper focuses on two issues that are important to those who use colour monitors for research in vision. One is concerned with the measurement and calibration of colour screens. To this end the luminance and chromaticity readings of a tri-filter colorimeter and a spectroradiometer are compared (both commonly used to calibrate screens). The second is concerned with screen interactions, whereby colours can be distorted from their expected or calculated values by the colours displayed in neighbouring areas. This issue is crucial for those who use measurements of the light emitted from the red, green and blue phosphors of a monitor in isolation to specify other colours on screen, particularly in the research areas of colour contrast and colour constancy, since the specified colours may not actually be displayed. Finally, an alternative calibration method is described that uses an iterative measurement procedure to obtain screen specifications that are accurate regardless of the display complexity, so that researchers can be confident that the required colours are actually displayed on the screen.     

Adsorption and decomposition of H2S on Pd(1 1 1) surface: a first-principles study

Gradient-corrected density functional theory was used to investigate the adsorption of H₂S on Pd(1 1 1) surface. Molecular adsorption was found to be stable with H₂S binding preferentially at top sites. In addition, the adsorption of other S moieties (SH and S) was investigated. SH and S were found to be preferentially bind at the bridge and fcc sites, respectively. The reaction pathways and energy profiles for H₂S decomposition giving rise to adsorbed S and H were determined. Both H₂S_(ad) → SH_(ad) + H_(ad) and SH_(ad) → S_(ad) + H_(ad) reactions were found to have low barriers and high exothermicities. This reveals that the decomposition of H₂S on Pd(1 1 1) surface is a facile process.     

Using transistors to linearise biochemistry

A fundamental relationship exists between diffusion characteristics within semiconductors and Nernstian equilibrium in biological systems. In a transistor operating in weak inversion the potential difference between terminals governs electron concentration in an exponential way according to the Boltzmann distribution of charged particles while in a biochemical cell the potential difference across a membrane is governed by ionic concentration in a logarithmic way according to the Nernst equation. These two nonlinear physical phenomena form an interaction that potentially leads to linearisation and subsequent modelling of or interaction with biological systems by integrated semiconductor devices. To demonstrate the authors' hypothesis a silicon transistor-based biosensor is considered. This natural bridge between biochemistry and semiconductor silicon chips will enable the potential mass production of portable biochemical devices for the consumer market     

Serum concentrations of cancer antigen 125, placental alkaline phosphatase, cancer-associated serum antigen and free beta human chorionic gonadotrophin as prognostic markers for epithelial ovarian cancer

OBJECTIVE: To investigate the prognostic significance of elevated levels of cancer antigen 125 (CA125), placental alkaline phosphatase (PLAP), free beta human chorionic gonadotrophin (hCG) and cancer-associated serum antigen (CASA) in women with primary epithelial ovarian carcinoma. DESIGN: A two year follow up study of survival. SETTING: A tertiary care gynaecological oncology unit. PARTICIPANTS: One hundred and eleven women with histologically confirmed epithelial ovarian cancer. MAIN OUTCOME MEASURES: Survival over a two year period. RESULTS: Stage corrected log-rank chi 2 tests demonstrated a significant effect on survival for all four tumour markers (CA125 P = 0.0142; PLAP P < 0.0001; CASA P = 0.0098; hCG P = 0.0002). This was confirmed when each variable was fitted together with disease stage in Cox proportional hazard models. When fitted as multiple variables in a Cox proportional hazard model, the addition of free beta-hCG and CASA to disease stage, PLAP concentrations and CA125 levels did not demonstrate further prognostic value. CONCLUSIONS: Levels of all four markers correlate with survival in patients with epithelial ovarian cancer. The combination of PLAP and CA125 concentrations together with disease stage may be used to predict survival but the addition of hCG and CASA levels do not give additional prognostic information.