Mechanical properties of medium density fiberboard reinforced with metal and woven synthetic nets

This research was planned to study the influence of reinforcement with metal and woven synthetic nets on the mechanical properties of medium density fiberboard (MDF). Sample boards were manufactured according to common practice. However, reinforcements were placed in the boards at one fourth of their thicknesses. Urea formaldehyde resin was used in the boards. However, some metal nets were embedded in an epoxy resin prior to board manufacture. Bending and tensile strengths were determined according to ASTM D 1037-99, impact load resistance according to ASTM D 256-04 and board’s creep according to ASTM D 6815-02. Results revealed that bending properties (MOE and MOR), tensile strength and impact load resistance were significantly increased due to the reinforcement. Boards reinforced with thin metal nets showed the highest MOR as 105% increase; while the highest MOE and impact load resistance were determined in the boards reinforced by thick metal nets, which were embedded primarily in the epoxy resin as 112% and 79%, respectively. The highest tensile strength was also determined in boards reinforced by thick metal nets. Boards reinforced by woven synthetic nets showed lower strengths than those of the metal nets.     

Lysozyme as a barrier to growth of Bacillus anthracis strain Sterne in liquid egg white, milk and beef

In this study, we investigated the role of lysozyme on the viability of Bacillus cereus, Bacillus subtilis, Bacillus pumilus and Bacillus anthracis (Sterne) in egg white (EW), ground beef and milk. At 35 °C in EW, growth rates (GR) for B. cereus, B. subtilis, B. pumilus and B. anthracis were 0.005, −0.018, −0.028 and −0.029 OD₆₀₀/h, respectively. Heat-treating EW at 55 and 60 °C reduced the inactivating effect of EW by 3.1 and 10.5-fold, respectively. Addition of lysozyme (2 mg/ml) to 60 °C-treated EW increased the inactivation rate 5.76-fold, indicating involvement of lysozyme in B. anthracis inactivation. B. anthracis inactivation was influenced by pH, as shown by a progressive increase in inactivation rate from 0.25 to −4.42 logs CFU/h over a pH range of 6.0-8.5. Adding 2 mg/ml lysozyme to milk and ground beef also suppressed the growth of B. anthracis 3.3 and 6.5-fold, respectively. These data indicate that lysozyme, as a natural component of EW or potential additive in other foods, could reduce biothreat risks presented by bioterror agents.     

Simplified model of the turbine runner blade

Francis turbine blade is modelled by circular beams loaded by uniformly distributed pressure. This simplification allows for analytical calculations of maximum stresses followed by comparisons with FEM analysis for the same turbine. Two beam models have been proposed and one of them showed good correlation with FEM for different operation conditions. This model has been applied to analyse the operation data recorded during the whole time of operation of the Unit 2 of Derbendikan hydropower station. The results show evolution of the maximum tensile stresses, which makes clear that the appearance of cracks in turbine blades cannot be explained by the high stresses level alone but by combination of different factors.     

MCR-NAS: A combined hard-soft multivariate curve resolution method based on net analyte signal concept for modeling kinetic data with inert interference and baseline drift

This paper demonstrates a novel implementation of a net analyte signal (NAS) algorithm for resolving kinetic model. The evaluation of spectroscopic kinetics data by the established hard-modeling approach assumes that all the variation related to the response is linked to the species involved in the kinetic process. If effects are present in the data that cannot be explained by the model, such as baseline drift or inert interference, the estimated rate constant might be incorrect. An iterative net analyte signal procedure is shown to yield good rate constant estimates when the spectroscopic data is influenced by additional sources of variance. Simulated and real examples are used to confirm this statement.     

Flood inundation extent in storage cell mode

An understanding of floodplain processes in general and floodplains flooding in particular are vital issues for river engineers and managers. Insufficient observations of flood inundation extent and the infrequent nature of flood inundation necessitate some sort of predictive tools. In this paper flood inundation extent has been simulated by HEC-RAS software in two storage cell and normal modes and capabilities and limitations of the two models have been determined by comparing simulated and observed flood inundation extent which occurred in the study area on Feb 4th, 2004.     

Preparation and characterization of multiwalled carbon nanotubes/polyacrylonitrile nanofibers

Multiwalled carbon nanotube/Polyacrylonitrile (MWNT/PAN) composite nanofibers were prepared by electrospinning technique, whereby functionalized MWNTs (F-MWNTs) and pristine MWNTs (P-MWNTs) were used as reinforcing materials. The F-MWNTs were functionalized by Friedel-Crafts acylation, which introduced aromatic amine (COC₆H₄-NH₂) groups onto the sidewall. The diameter range of the PAN nanofibers was 400-100 ± 50 nm. The beads formation was also observed when the amounts of MWNTs were increased in the PAN solution. The bead formation in F-MWNT/PAN composite nanofibers was less as compared to P-MWNT/PAN. The MWNTs were embedded within nanofibers and were well oriented along the nanofiber axis, as confirmed by transmission electron microscopy. The mechanical and thermal properties of the PAN nanofibers were improved by the incorporation of MWNTs.