An Evaluation of Total Flooding High Expansion Foam Fire Suppression Systems for Machinery Space Applications

Full-scale fire tests were conducted to identify the fire extinguishing capabilities and limitations of High Expansion Foam Fire Suppression Systems (HEFFSS) in shipboard machinery space applications. A total of 35 tests were conducted in this evaluation utilizing the equipment and foam concentrates from three manufacturers. Each manufacturer was responsible for the design of their respective system. These designs were based on the minimum SOLAS/FSS Code requirements plus some additional capacity to provide a factor of safety for these tests. Each system was evaluated against the three large fire scenarios described in the International Maritime Organization's (IMO) gaseous agent test protocol (MSC/Circ. 848). The reason the HEFFSS test protocol (MSC/Circ. 670) was not used is discussed in the article. In addition to the tests in MSC/Circ. 848, parametric assessments of fill rate, fire size and type, and the use of inside air (the products of combustions) to make the foam were also conducted (one parameter for each of the three systems). In summary, there were significant differences in capabilities between the three systems. All three systems easily extinguished the pan fires included in this evaluation independent of the type of fuel (heptane or diesel). The differences in system capabilities were observed during the extinguishment of the spray fires (namely the heptane spray fires). The heptane spray fires presented a major challenge to the HEFFSS and in some cases, were not extinguished.     

The relevance and use of information and telecommunication networks as strategic tools in the transport sector: a Dutch case study

New information and telecommunication technologies in the transport sector, often named Advanced Transport Telematics (ATT), play a key role in the new European network economy, as they have the potential to offer new solutions to the emerging transport problems in Europe. However, the successful exploitation of ATT in European transport markets depends on the technology being implemented in a way which meets the distinct needs of the different road user groups in order to achieve social acceptance and thereby political approval. It is therefore vitally important that decision makers (i.e. those influencing the adoption of ATT) have sufficient information on the needs of (commercial) road users and on the way they perceive ATT options in addressing those needs. The ATT market comprises a large number of actors from both the public and the private sector. At the demand side, some major potential market sectors can be identified. In addition to private users, there are intermediate or collective users (e.g., road authorities) and commercial users (e.g., the freight sector). In the latter case ATT may play a strategic role by facing the need of the freight sector to orient itself towards the opportunities offered by the European internal market, which has farreaching impacts not only on organisations operating in international networks, but also on those operating nationally. The aim of the underlying study is to investigate the potential ATT market among these main user and interest groups, where the range of telematics applications will be restricted to those applied to inter-urban road transport. The focus will be on collective users (road managers) and commercial users (road freight operators). Surveys and in-depth interviews have been used to gather relevant information on the views, attitudes and expectations of these potential users. This empirical information provides interesting and policy relevant insights into the potential of ATT applications for each of these market segments.     

Practical mathematical representation of the flow due to a distribution of sources on a steadily advancing ship hull

A practical mathematical representation of the flow velocity due to a distribution of sources on the mean wetted hull surface and the mean waterline of a ship that steadily advances along a straight path in calm water, of large depth and lateral extent, is presented. A main feature of this flow representation is a simple analytical approximation—valid within the entire flow region—to the local flow component in the expression for the gradient of the Green function associated with the classical Kelvin–Michell linearized free-surface boundary condition. Another notable feature of the flow representation is that the singularity associated with the gradient of the Green function is removed, using a straightforward regularization technique. The flow representation only involves elementary continuous functions (algebraic, exponential and trigonometric) of real arguments. These functions can then be integrated using ordinary Gaussian quadrature rules. Thus, the flow representation is particularly simple and well suited for practical flow calculations. The specific case of a low-order panel method—in which the hull geometry, the source density, and the flow velocity are consistently represented via piecewise linear approximations within flat triangular hull panels or straight waterline segments—is considered.     

Tunable contact resistance in double-gate organic field-effect transistors

A study of the contact resistance (R_sd) in pentacene-based double-gate transistors is presented. In top-contact transistors, as the negative bias of the additional top-gate bias is increased, R_sd decreases by over five orders of magnitude for small bottom-gate voltages. In bottom-contact transistors, R_sd is reduced by about ten times for all bias values, implying improved charge transport in all operating regimes. The different tunability of R_sd in top/bottom-contact transistors is attributed to different charge injection modulation by the coplanar/staggered top gate. Therefore, double-gate architecture offers a novel and effective approach to limit R_sd and its relevant impacts on organic transistor.     

Design and experimental validation of a nonlinear wheel slip control algorithm

We present a new wheel slip controller and validate it both experimentally and in simulation. The control strategy is based on both wheel slip and wheel acceleration regulation, and ensures global asymptotic stability in closed loop. The stability analysis is established using tools for cascaded systems. This approach has the advantage of setting conditions on the control gains that are considerably milder, if compared with those obtained from Lyapunov’s direct method. Simulations are provided to illustrate the robustness against vertical load variations and uncertainties in tyre–road friction. Furthermore, tests on a tyre-in-the-loop facility show that with our control law the wheel slip converges precisely to the assigned reference.     

Tailoring the morphology of methacrylate ester-based monoliths for optimum efficiency in liquid chromatography

Methacrylate ester-based monolithic stationary phases were prepared in situ in fused-silica capillaries and simultaneously in vials. The influence of the composition of the polymerization mixture on the morphology was studied with mercury intrusion porosimetry, scanning electron microscopy, and nitrogen adsorption measurements. A high-density porous polymeric material with a unimodal pore-size distribution was prepared with 40 wt % monomers and 60 wt % solvent in the mixture. A low-density material, prepared with a 20:80 ratio of monomers versus pore-forming solvent, showed a bimodal pore-size distribution and a much finer structure than the high-density monolith. The characteristic pore size could be controlled by changing the ratio of pore-forming solvents. With increasing solvent polarity, both the pore size and the dimension of the globules increased. The best efficiency in the CEC mode was obtained with an average pore size of 600 nm. Low-density monoliths exhibited lower A- and C-terms than high-density monoliths. With the optimal monolithic material, a minimum plate height of 5 mum could be obtained. The low-density monolith also performed better in the HPLC mode, giving a minimum plate height of 15 mum and a much higher flow permeability than that of the high-density material.     

Role of silane coupling agent and polymeric film former for tailoring glass fiber sizings from tensile strength measurements

Tensile strengths of differently sized E-glass fibres have been characterised using a bimodal Weibull two parameters cumulative distribution function. By comparing unsized fibres, pure silanes, different film formers, and silane/film former combinations, a comprehensive summary on the healing effect for surface flaws in relation to the type of sizing emulsion has been obtained. The great influence of the film former, which is the main component of the sizing by weight, was shown to affect both the healing of initially occuring flaws in the unsized fibre and the possibility of creating new defects. Besides the single influence of the film former, the synergetic effect of silane and film former polymer has been shown. In fact, the presence of sizing influences both the population of flaws on the fibre surface and the structure of the interphase, which will be created from the impregnation with a polymer matrix. Data from statistics of fracture as a function of the nature of sizings were discussed according to the literature on stress corrosion of E-glass filaments.     

Evaluation of D(d,n)3 He reaction neutron source models for BNCT irradiation system design

A mathematical method was developed to calculate the yield,energy spectrum and angular distribution of neutrons from D(d,n)~3He(D-D)reaction in a thick deuterium-titanium target for incident deuterons in energies lower than 1.0MeV.The data of energy spectrum and angular distribution were applied to set up the neutron source model for the beam-shaping-assembly(BSA)design of Boron-Neutron-Capture-Therapy(BNCT)using MCNP-4C code. Three cases of D-D neutron source corresponding to incident deuteron energy of 1000,400 and 150 key were inves- tigated.The neutron beam characteristics were compared with the model of a 2.45 MeV mono-energetic and isotropic neutron source using an example BSA designed for BNCT irradiation.The results show significant differences in the neutron beam characteristics,particularly the fast neutron component and fast neutron dose in air,between the non-isotropic neutron source model and the 2.5 MeV mono-euergetic and isotropic neutron source model.