Preservative Effect on Stress-Laminated Southern Pine Bridge Decks

Stress-laminated timber bridge decks have gained increasing popularity in the United States in recent years. As with all wood exposed to the environment, wood for these decks must be treated with preservatives. There has been reluctance to build chromated-copper-arsenate (CCA) –treated wood bridges due to concerns about dimensional stability. Because no research has been undertaken to investigate the use of CCA-treated southern pine in stress-laminated bridge decks, a good resource for economic rural bridges has remained untapped. The objective of this study was to evaluate the performance of various wood preservatives on stress-laminated southern pine bridge decks. A total of nine decks with seven different preservatives were built and exposed to the environment for more than 2 years. Force levels in prestressing bars and wood moisture contents from each deck were continuously monitored. It was found that the short-term variations in the bar stress levels are less for decks with oil-type preservatives, as compared to CCA preservatives. The long-term performance for decks with both preservative types was found to be similar. The anchorage effect on the deck performance was found to be negligible.     

Critical roasting level determines bioactive content and antioxidant activity of Robusta coffee beans

Food Science and Biotechnology - Indonesian Lampung Robusta coffee green beans were roasted at eight roasting levels (green bean, early yellow, brown, 1st crack done, very light, light, medium, and...     

Effects of oleaster flour supplementation in total phenolic contents,antioxidant capacities and their bioaccessibilities of cookies

Food Science and Biotechnology - In presented study total phenolic contents, antioxidant capacities and their bioaccessibilities from cookies supplemented with oleaster flour were investigated....     

An overview of toughening polylactic acid by an elastomer

Due to environmental concern and depletion of fossil fuel, research on biopolymer is gaining interest among researchers. Polylactic acid (PLA) is produced from renewable resources. PLA has high tensile strength and high modulus, and it can be processed by using conventional processing methods. However, some properties of PLA limit the usage, such as brittleness, low impact resistance, low thermal stability, and high cost. Overall, the toughening approach of PLA, blending with elastomer has been one of the main focuses. This review paper is intended to provide general information regarding progress made in PLA toughening by an elastomer.     

Heat transfer enhancement for combined convection flow of nanofluids in a vertical rectangular duct considering radiation effects

In this paper, combined convective heat transfer and nanofluids flow characteristics in a vertical rectangular duct are numerically investigated. This investigation covers Rayleigh numbers in the range of 2 × 10⁶ ≤ Ra ≤ 2 × 10⁷ and Reynolds numbers in the range of 200 ≤ Re ≤ 1000. Pure water and five different types of nanofluids such as Ag, Au, CuO, diamond, and SiO₂ with a volume fraction range of 0.5% ≤ φ ≤ 3% are used. The three‐dimensional steady, laminar flow, and heat transfer governing equations are solved using finite volume method (FVM). The effects of Rayleigh number, Reynolds number, nanofluids type, nanoparticle volume fraction of nano‐ fluids, and effect of radiation on the thermal and flow fields are examined. It is found that the heat transfer is enhanced using nanofluids by 47% when compared with water. The Nusselt number increases as the Reynolds number and Rayleigh number increase and aspect ratio decreases. A SiO₂ nanofluid has the highest Nusselt number and highest wall shear stress while the Au nanofluid has the lowest Nusselt number and lowest wall shear stress. The results also revealed that the wall shear stress increases as Reynolds number increases, aspect ratio decreases, and nanoparticle volume fraction increases. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.20354     

Impacts of Hypoxia on Osteoclast Formation and Activity: Systematic Review

Hypoxia is evident in several bone diseases which are characterized by excessive bone resorption by osteoclasts, the bone-resorbing cells. The effects of hypoxia on osteoclast formation and activities are widely studied but remain inconclusive. This systematic review discusses the studies reporting the effect of hypoxia on osteoclast differentiation and activity. A literature search for relevant studies was conducted through SCOPUS and PUBMED MEDLINE search engines. The inclusion criteria were original research articles presenting data demonstrating the effect of hypoxia or low oxygen on osteoclast formation and activity. A total of 286 studies were identified from the search, whereby 20 studies were included in this review, consisting of four in vivo studies and 16 in vitro studies. In total, 12 out of 14 studies reporting the effect of hypoxia on osteoclast activity indicated higher bone resorption under hypoxic conditions, 14 studies reported that hypoxia resulted in more osteoclasts, one study found that the number remained unchanged, and five studies indicated that the number decreased. In summary, examination of the relevant literature suggests differences in findings between studies, hence the impact of hypoxia on osteoclasts remains debatable, even though there is more evidence to suggest it promotes osteoclast differentiation and activity.     

Deficiency Analysis of Coastal Buildings toward Storm Damage Reduction

Engineering services provided by one of the writers to property owners, insurance companies, attorneys, and others have resulted in a compilation of case studies, based on more than 1,000 site inspections, suitable to generate a database regarding various aspects of building performance. The scope of those services typically included identifying the cause and origin of damage to residential and commercial structures, as well as an estimation of the magnitude of damage sustained by those structures. The majority of those damaged structures was located in proximity to a coastal region and experienced recent exposure to a storm or other weather event. Compilation of data from those case studies allowed identification and ranking of the occurrence of chronic building problems. It has become apparent that building-related deficiencies often exist as a common feature in similar structures. Some of those recurring deficiencies could be eliminated with alternate building design, better construction practices, or proper routine maintenance procedures. Where applicable, proposed remedial solutions are presented for specific building deficiencies or problems identified.     

Respirometric evaluation of a mixture of organic chemicals with different biodegradation kinetics

The study evaluated the biodegradation characteristics of a mixture of organics with different biodegradation characteristics in an integrated chemical plant effluent. The wastewater had a total chemical oxygen demand (COD) content of 12,800mg/L, mostly soluble and 93% biodegradable. The evaluation was based on respirometry, and mainly consisted on model calibration and interpretation of the oxygen uptake rate data, which exhibited an original and specific profile with a sequence of two peaks and three plateaus. A specific model was defined for this purpose, which identified four different biodegradable COD components with significantly different process kinetics. The major fraction accounting for 57% of the total biodegradable COD in the wastewater had to be hydrolyzed before biodegradation with a low hydrolysis rate of 1.3day(-1). The analysis of the experimental data showed that the oxygen utilization started with a delayed response after substrate addition. The delayed logarithmic phase could be characterized by a Haldane type of inhibition kinetics.     

Comparison of analytical techniques for dynamic trace metal speciation in natural freshwaters

Several techniques for speciation analysis of Cu, Zn, Cd, Pb, and Ni are used in freshwater systems and compared with respect to their performance and to the metal species detected. The analytical techniques comprise the following: (i) diffusion gradients in thin-film gels (DGT); (ii) gel integrated microelectrodes combined to voltammetric in situ profiling system (GIME-VIP); (iii) stripping chronopotentiometry (SCP); (iv) flow-through and hollow fiber permeation liquid membranes (FTPLM and HFPLM); (v) Donnan membrane technique (DMT); (vi) competitive ligand-exchange/stripping voltammetry (CLE-SV). All methods could be used both under hardwater and under softwater conditions, although in some cases problems with detection limits were encountered at the low total concentrations. The detected Cu, Cd, and Pb concentrations decreased in the order DGT > or = GIME-VIP > or = FTPLM > or = HFPLM approximately = DMT (>CLE-SV for Cd), detected Zn decreased as DGT > or = GIME-VIP and Ni as DGT > DMT, in agreement with the known dynamic features of these techniques. Techniques involving in situ measurements (GIME-VIP) or in situ exposure (DGT, DMT, and HFPLM) appear to be appropriate in avoiding artifacts which may occur during sampling and sample handling.