Surface mechanical strength optimization of ZrO2 physical vapour deposition coatings

We present a reactive magnetron sputtering technique yielding adherent mixed +β ZrO₂ coatings on cutting tools. The coatings are optimized by means of a laboratory mechanical testing procedure based essentially on single-pass scratch testing of construction steel, high speed steel and cemented carbide substrates. Machining of the free cutting steel S300Si yields protective layers on ZrO₂- coated K20 tools (94%WC-6%Co binder) owing to selective transfer of MnS inclusions leading to tool life enhancement superior to that of commercial P30 mixed carbide tools.     

Chemical,nutritional and physiological aspects of dry bean carbohydrates—A review

The current knowledge of dry bean carbohydrates related to their composition, nutritional value and physiological attributes in humans is reviewed. Dry bean carbohydrates represent up to 60% of the total seed weight and starch is the major constituent. Molecular and physicochemical properties of legume starches are also discussed. Data to indicate the possible involvement of the raffinose family of oligosaccharides in flatulence production are given.     

A study of short-pulse coupling

The multiple scattering of electromagnetic waves by two-body target configurations has been studied in terms of their sub-nanosecond pulse returns. The wide-band response of targets has been computed through the use of an asymptotic solution to simple two-body scattering problems and is discussed with emphasis on target coupling phenomenon. Low-order coupling components between bodies were isolated experimentally through use of a coherentX-band high-resolution radar system, and the results are generally in good agreement with the analytical solutions.     

Panel flutter optimization by gradient projection

A gradient projection optimal control algorithm incorporating conjugate gradient directions of search is described and applied to several minimum weight panel design problems subject to a flutter speed constraint. New numerical solutions are obtained for both simply-supported and clamped homogeneous panels of infinite span for various levels of inplane loading and minimum thickness. The minimum thickness inequality constraint is enforced by a simple transformation of variables.     

The chemical vapor deposition of carbon on carbon fibers

The relations between chemical vapor deposition (CVD) parameters and the resultant pyrolytic carbon microstructures have been examined for matrix deposition in fibrous carbon substrates. The parameters considered are temperature (1200–1450°C), pressure (20–630 Torr), C/H ratio ($\text{1}\text{4}\text{–}\text{1}\text{14}$), total flow rate (2–16) 1/min), and carbon felt density (0·12–0·23 g/cm³). Most of the data obtained are in agreement with a CVD model for carbon; where agreement is not obtained, it is surmised that the assumptions of the model may not be satisfied.     

The chemical vapor deposition of TiB2 from diborane

In this paper we describe an experimental study of the chemical vapor deposition of titanium diboride on graphite using the reaction of TiCl₄ with B₂H₆ in a hydrogen atmosphere in the temperature range 600–900 °C. Dense and adherent coatings were obtained varying in composition from boron rich at 600 °C (TiB_3.12) to stoichiometric above 700°C. There was a gradual increase in crystalline size with increasing deposition temperature. Chlorine tended to remain incorporated in the deposit (1.86 at.% at 600 °C decreasing to 0.51% at 900 °C). The coatings were very hard ($\text{HV = 3715 kgf mm}{}^{\mathrm{?2}}$).     

Suppression of Salmonella growth by wild-type and large-plaque variants of bacteriophage Felix O1 in liquid culture and on chicken frankfurters

The bacteriophage Felix O1, a member of Myoviridae, is specific for, and possesses a broad host range within, the genus Salmonella. This work explores a Felix O1 phage-based intervention for Salmonella enterica serotype Typhimurium DT104 that is potentially applicable at several stages of animal production and processing. A variant of Felix O1 was obtained that produces a larger, clearer plaque phenotype (LP) on Salmonella Typhi than wild-type Felix O1 (WT) does, not unlike r mutants of phage T4. LP exhibited slightly more extensive overall suppression of Salmonella Typhi in brain heart infusion (BHI) broth, as ascertained on the basis of culture turbidity (optical density at 600 nm). Both phage variants suppressed log phase BHI broth cultures containing 8.2 x 10(6) CFU of Salmonella Typhimurium DT104 per ml. A PFU/CFU ratio of 1.0 was effective for WT and LP, whereas increasing the PFU/CFU ratio to 5.0 did not increase suppression. Untreated Salmonella-contaminated frankfurters were compared with treated samples (PFU/CFU ratio, 1.9 x 10(4)) to test WT and LP for their ability to suppress Salmonella growth on chicken frankfurters contaminated with 300 CFU of Salmonella Typhimurium DT104. Suppression levels of 1.8 and 2.1 log units were achieved with WT and LP, respectively (P = 0.0001), but no difference was found between the performances of the two variants (P = 0.5088).     

The role of energy limited hydro equipment in an optimal plant mix

The main purpose of this paper is to highlight the influence of the main characteristics of hydropower on the choice of an optimal generating plant mix. Marginal conditions for a cost minimizing approach are developed while incorporating the effects of the rising costs of hydraulic forces, the cost of added hydroturbines (energy limited), and the costs of developing different hydro sites. It is seen that the main difference between the marginal conditions for a hydro system and for a thermal one comes from the limited availability of water power. This framework is then applied to data drawn from the current expansion programme of Quebec Hydro. Although the analytical framework relies on simplifying assumptions, the results are rather close to those provided by Quebec Hydro. The results are then used to evaluate the marginal costs of providing additional power for every hour of the year. These marginal generation costs range from a high of 6.0¢ during the peak period to a low of 1.6 ¢ for the base period, both being measured in 1980 dollars.