Experimental study on PC hollow-core slab strengthened with bamboo plates

An experimental study on strengthening prestressed concrete (PC) hollow-core slabs was conducted. Nine PC hollow-core slabs were tested, including three unstrengthened reference slabs and six slabs strengthened with bamboo plates. The results show that compared with unreinforced slabs, the cracking loads of PC hollow-core slabs strengthened with bamboo plates increase by 5% to 96% (with an average of 41%), the loads at allowable deflection increase by 8% to 76% (with an average of 35%), and the ultimate loads increase by 83% to 184% (with an average of 123%), respectively. All the degrees of improvement in the crack load, allowable load and ultimate load increase with the increase in the thickness and width of the bamboo plates. With the increase in the loads, the strain distribution along the height of the strengthened slabs at the mid-span basically remains a plan-assumption. With the increase in the thickness and width of the bamboo plates, both the bamboo tensile strain on the tensile face and the concrete compressive strain on the compression face of the strengthened slabs decrease under the same load level.

Improved Equivalent Frame Analysis Method for Flat Plate Structures in Vicinity of Edge Columns

This paper proposes a modification to the ACI 318-02 equivalent frame method of analysis of reinforced concrete flat plate exterior panels. Two existing code methods were examined: ACI 318 and BS 8110. The derivation of the torsional stiffness of the edge strip as proposed by ACI 318 is examined and a more accurate estimate of this value is proposed, based on both theoretical analysis and experimental results. A series of 1/3-scale models of flat plate exterior panels have been tested. Unique experimental results were obtained by measuring strains in reinforcing bars at approximately 200 selected locations in the plate panel throughout the entire loading history. The measured strains were used to calculate curvature and, hence, bending moments; these were used along with moments in the columns to assess the accuracy of the equivalent frame methods. The proposed method leads to a more accurate prediction of the moments in the plate at the column front face, at the panel midspan, and in the edge column. Registered Subscribers: View the full article. This document is available as a free download to qualified members. An electronic (PDF) version is available for purchase and download. Click on the Order Now button to continue with the download.

The Chinese bamboo leaf odorous frog (Rana (Odorrana) versabilis) and North American Rana frogs share the same families of skin antimicrobial peptides.

The Chinese bamboo leaf odorous frog (Rana (Odorrana) versabilis) and the North American pickerel frog (Rana palustris) occupy different ecological niches on two different continents with no overlap in geographical distribution. R. palustris skin secretions contain a formidable array of antimicrobial peptides including homologs of brevinin-1, esculentin-1, esculentin-2, ranatuerin-2, a temporin and a family of peptides considered of unique structural attributes when isolated, palustrins 1–3. Here we describe the structures of mature peptides and precursors of eight putative antimicrobial peptides from the skin secretion of the Chinese bamboo leaf odorous frog (Rana (Odorrana) versabilis). Each peptide represents a structural homolog of respective peptide families isolated from R. palustris, including two peptides identical in primary structure to palustrin 1c and palustrin 3b. Additionally, two peptides were found to be structural homologs of ranatuerin 2B and ranatuerin 2P from the closely-related North American species, Rana berlandieri (the Rio Grande leopard frog) and Rana pipiens (the Northern leopard frog), respectively. Both palustrins and ranatuerins have hitherto been considered unique to North American ranid frogs. The use of primary structures of amphibian skin antimicrobial peptides is thus questionable as a taxonomic device or alternatively, the micro-evolution and/or ancestry of ranid frogs is more highly complex than previously thought.

Stiffened panel stability behaviour and performance gains with plate prismatic sub-stiffening

To increase the structural efficiency of integrally machined aluminium alloy stiffened panels, it is plausible to introduce plate sub-stiffening to increase the local stability and thus panel static strength performance. Reported herein is the experimental validation of prismatic sub-stiffening, and the computational verification of such concepts within larger recurring structure. The experimental work demonstrates the potential to 'control' plate buckling modes. For the tested sub-stiffening design, an initial plate buckling performance gain of +89% over an equivalent mass design was measured. The numerical simulations, modelling the tested sub-stiffening design, demonstrate equivalent behaviour and performance gains (+66%) within larger structures consisting of recurring panels. (C) 2009 Elsevier Ltd. All rights reserved.

GK-22 amide: a novel myotropic peptide from the skin secretion of the bamboo leaf odorous frog, Odorrana versabilis

The skin secretions produced by many amphibians are formidable chemical/biological weapons deployed as a defence against predators. Bioactive peptides are often the predominant class of biochemical within these secretions and the inventory of such remains incomplete with each individual taxon producing unique cocktails contained within which are some signature peptides, such as bradykinins and tachykinins. These secretions have been the source of many peptides subsequently found to have structural homologues in vertebrate neuroendocrine systems (bombesin/GRP; sauvagine/CRF; caerulein/CCK) and vice versa (bradykinin, CGRP, NMU). They are thus unequivocally intriguing resources for novel bioactive peptide discovery. Here we describe a novel 22-mer amidated peptide, named GK-22 amide (N-terminal Gly (G) and C-terminal Lys (K) amide) with an internal disulphide bridge between Cys (C) 11 and 20 from the skin secretion of Odorrana versabilis. Molecular cloning indicated that it is encoded as a single copy on a biosynthetic precursor of 59 amino acid residues consisting of a signal peptide, an acidic amino acid residue-rich spacer domain and a mature peptide encoding domain flanked N-terminally by a classical -Lys-Arg- (KR) propeptide convertase processing site and C-terminally by a Gly (G) residue amide donor. A synthetic replicate of this peptide produced potent and dose-dependent contraction of the smooth muscle of rat urinary bladder. GK-22 amide thus represents the prototype of a novel class of myotropic peptide from amphibian skin and its discovery illustrates the continuing potential of this resource to this end.

Separation of acid-dyes mixture by bamboo derived active carbon

In the present study, the activated carbon is produced using phosphoric acid treatment of the waste bamboo scaffolding and activated at either 400 or 600 °C. The effect of acid to bamboo ratio (Xp) up to 2.4 has been studied. The BET surface area increased with increasing Xp and activating temperature. BET surface area up to 2500 m2/g carbon has been produced. In order to simulate effluent treatment from textile industry, the produced carbon was tested for its dye adsorption capacities. Two acid dyes with different molecular sizes were used, namely Acid Yellow 117 (AY117) and Acid Blue 25 (AB25). In a single component system, it was found that dye with smaller molecular size, AB25, was readily adsorbed onto the carbon while the larger size dye, AY117, showed little adsorption. As a result, it is possible to tailor-make the carbon for the adsorption of dye mixtures in industrial applications, especially textile dyeing, i.e. molecular sieve effect. A binary AY117–AB25 mixture was used to test the possibility of the molecular sieve effect. Furthermore, experimental results were fitted to equilibrium isotherm models, Langmuir, Freundlich and Sips for the single component system. For the binary component system, extended single-component equilibrium isotherm models were used to predict the experimental data.

3D Analysis of Heat Transfer Intensification by Re-Entrance Flow Pin-Fins Microstructures with a Highly Thermal-Conductive Plate

Joule heat-induced hot-spot formation sets severe limits in the operation of continuous annular electrochromatography (CAEC), a new concept for preparative separation as an analog to analytical capillary electrochromatography (CEC). This may lead to eluent flow perturbance, even to boiling, which would massively weaken separation efficiency and may even hamper the stationary phase used for separation. For reasons of system integration and high-efficiency heat transfer, micro flow heat exchangers are considered with a separate coolant flow. A 3D numerical analysis of the heat transfer of water single-phase laminar flow in a square microchannel and different arrays of micro pin-fins was carried out using COMSOL Multiphysics. Several advanced materials with low electric conductivity and at the same time with high heat conductivity were put forward to be used in the CAEC system. As essential design point, it is proposed to constitute the micro heat exchanger from two different parts of the CAEC system, namely a microstructured pin-fins plate and a so-called conductive plate.