Finite element analysis of fibre composite sandwich panel

This research work aims to understand the behaviour of fibre composite sandwich panel by using nonlinear Finite Element (FE) method. The original FRP sandwich panel is associated with waste of materials usage related to its ability to resist the external load and stay in the working load serviceability. The experimental analysis was done by CEEFC in the University of Southern Queensland and it showed that the failure load is (5-10) times the working load recommended by EUROCOMP. The analysis of composite FRP panel using 3D solid Finite Element and shell element shows a relatively accurate simulation for the behaviour of the FRP panel compare to the experimental results. The objective of this research is to verify the behaviour of FRP sandwich panel by using finite element methods. The numerical finite element model using traditional available ABAQUS software was developed to simulate the structural behaviour of FRP panel

Zur Kenntnis der Rotatorienfauna (Rotifera) der Insel Hainan, China : Teil 2

Im Dezember 1995 wurden aus verschiedenen Gewässertypen der Insel Hainan, China, Proben genommen, um sie auf das Vorkommen von Rotatorien (Rädertiere) zu untersuchen. Es konnten 195 Spezies nachgewiesen werden, davon 187 monogononte und 8 digononte (bdelloide) Arten. Daneben wurden Formen aus 5 Gattungen und Bdelloidae beobachtet, deren Identifikation aufgrund von Konservierungsartefakten nicht möglich war. Von den nachgewiesenen Arten ist Cephalodella qionghaiensis neu für die Wissenschaft, daneben werden von Keratella micracantha eine neue Form und von Notholca acuminata eine neue Varietät beschrieben.In December 1995 sam pies were collected from different water bodies located on the Island of Hainan, China. 195 species were found. Among these sampies, there were 187 Monogononta und 8 Digononta (Bdelloidae). Further rotifers belonging to five genera and to the Bdelloidae could not be identified to species level, because determination was hindered by preservation artifacts. Among the species found, Cephalodella qionghaiensis is new to science. Additionally, a new form of Keratella micracantha and a new variety of Notholca acuminata could be described

Flexural behaviour of a sustainable hybrid composite panel using natural fibres

Although many efforts have been made to utilize natural fibers for building components, most were found to be either structurally or economically unviable. A bio-based building component with higher structural performance is normally achieved at the expense of significantly higher cost as a larger size is typically required. Similarly, reducing the size to maintain the cost will only produce a building component with lower structural perforce that may not competitive with conventional building materials. In order to overcome these shortcomings, a hybrid sandwich panel was developed where a natural fiber composite (NFC) laminate is placed as an intermediate layer in between an aluminum skin and an EPS core. This paper presents the research outcomes of the flexural behavior of this hybrid composite sandwich panel which can be manufactured as modular panelized system. Two different types of natural fiber reinforced plastics (NFRP) laminate were incorporated into the new sandwich panel as an intermediate layer and their performance were compared. The flexural behavior was investigated through experimental testing

Reduced complexity on video encoding for wireless multimedia sensor networks

A wireless multimedia sensor network (WMSN) requires a video encoding system that should be energy-efficient because of its special characteristics: limited power capacity but long service life without maintenance. Besides, video is one of the most important information contents that a WMSN delivers. Motion estimation plays an important role in predictive coding, which is the key part of video encoding and requires large amount of computation. In order to reduce the computational complexity of motion estimation, the block-matching search algorithm is able to find the motion vectors using fewer search points. An algorithm which adds a predictive search technique to the enhanced modified orthogonal search (EMOS) has been proposed. It improves the efficiency of block-matching search algorithms, and has two self-adapting search patterns for large and small movements. The proposed algorithm requires less search points to work out the movement of blocks and provides acceptable image quality. This algorithm was also tested on field programmable gate array (FPGA) and Arduino platforms. Moreover, a back propagation neural network model is introduced for predictive block-matching. The proposed back propagation neural network has very simple structure with only 5 inputs, 5 hidden neurons and 1 output architecture. Because of its simplicity, it requires very little computational power which is negligible compared with existing computation complexity. The test results show the prediction accuracy in 10 - 30\% higher then the competing algorithms with a peak signal-to-noise ratro (PSNR) improvement up to 0.3 dB. The above advantages make it a feasible replacement of the current solution. With the information technology developing dramatically, there is reason to believe that the next generation video encoding standard HEVC will soon be able to run on very cheap platforms. Therefore, a prospective study on HEVC inter prediction acceleration was also carried out. We extracted specific image features that represent prediction unit texture, incorporated a machine learning technique, namely random forest, in HEVC intra prediction mode selection, to improve the performance of inter coding of HEVC. Benchmarking with other existing algorithms, our method extracts very specific features of image texture changes in terms of angle. Therefore the proposed method can achieve very high prediction accuracy. Having similar reduction in complexity, the proposed algorithm will be demonstrated to have a higher video quality compared with similar algorithms

Flexural strength of sandwich panel with lignocellulosic composites intermediate layer: a statistic approach

In this study, three different types of lignocellulosic composite materials have been incorporated in sandwich panel structure as an intermediate layer. The experiment was statistically designed based on single factor analysis scheme. The results of experiments have been analyzed using analysis of variance (Anova) followed by Tukey's, Fisher's and Dunnet's tests to obtain the information of how significant those materials contribute to the flexural strength of sandwich panel structure. The total number of samples tested was 48 beams. The results show that the introduction of lignocellulosic composites materials, that are hardboard, medium density fibre (MDF) and plywood, has significantly improved the flexural strength of sandwich panel. The range of improvement contributed by the presence of lignocellulosic composites intermediate layer was around 100 – 150% for samples with balsa core and 130-150% for samples with polystyrene core. The result of this study shows the potential of lignocellulosic composite material to be developed further for producing more sustainable sandwich panel

Flexural Strength of Innovative Thin-Walled Composite Cold-Formed Steel/PE-ECC Beams

A detailed experimental investigation on the flexural behaviour of an innovative precast composite element combining cold-formed steel (CFS) and engineered cementitious composites (ECC) is presented in this paper. Bonding ECC to the lightweight thin-walled CFS sections enhanced the buckling, bearing, and torsional properties of the composite sections. The proposed composite system will be used as precast flexural members in framed structures with large spans or as a rehabilitation approach for corroded cold-formed and hot-rolled steel flexural members. Simply supported beams with comparatively long spans with span-to-depth ratios of 6.83 and 13.48 were installed back-to-back and tested under a 4-point loading configuration. The behaviour of composite CFS/ECC beams under bending was investigated and compared with the bare CFS sections. Composite CFS/MOR beams incorporating high-strength mortar (MOR) as an ECC replacement were also investigated. The test specimens were divided into three series with sixteen tests in total. Series A (SC300) included six tests utilising 300-mm height SupaCee sections, Series B (C300) included four tests using 300-mm height lipped-Cee sections, and Series C (SC150) included six tests utilising 150-mm height SupaCee sections. The composite CFS/ECC beams exhibited high load-bearing capacities after reaching their plastic section capacities, while the bare CFS beams failed to reach their yield section capacities due to distortional buckling. Composite CFS/MOR beams could not reach their plastic moment capacities due to debonding between MOR and CFS after MOR crushing. The moment capacities of the composite CFS/ECC beams increased up to 140.0% over their duplicate bare CFS sections, while composite CFS/MOR beams showed only a 72.0% increase over CFS sections. Lastly, design equations to predict the moment capacity of composite CFS/ECC beams are presented, based on the experimental results

Comparison of Non-human Primate versus Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes for Treatment of Myocardial Infarction.

Non-human primates (NHPs) can serve as a human-like model to study cell therapy using induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). However, whether the efficacy of NHP and human iPSC-CMs is mechanistically similar remains unknown. To examine this, RNU rats received intramyocardial injection of 1 × 107 NHP or human iPSC-CMs or the same number of respective fibroblasts or PBS control (n = 9-14/group) at 4 days after 60-min coronary artery occlusion-reperfusion. Cardiac function and left ventricular remodeling were similarly improved in both iPSC-CM-treated groups. To mimic the ischemic environment in the infarcted heart, both cultured NHP and human iPSC-CMs underwent 24-hr hypoxia in vitro. Both cells and media were collected, and similarities in transcriptomic as well as metabolomic profiles were noted between both groups. In conclusion, both NHP and human iPSC-CMs confer similar cardioprotection in a rodent myocardial infarction model through relatively similar mechanisms via promotion of cell survival, angiogenesis, and inhibition of hypertrophy and fibrosis

Assessing functional and structural cardiotoxicity in cultured human iPSC-cardiomyocytes in a single plate format

Présentation PosterInternational audienceA comprehensive profiling of cardiotoxicity early in drug discovery and development can aid in reducing late-stage attrition and establishing risk-mitigation strategies during clinical development. In most cases, multiple assay platforms and instrument-specified plate formats are required for this type of approach. In this study, we evaluated both functional and structural endpoints associated with cardiotoxicity in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) cultured in a single 384-well plate. We measured intracellular Ca2+ transit, caspase 3/7 activation and plasma membrane permeabilization sequentially in the same plate via a series of assay readouts. A set of cardiac ion channel modulators (dofetilide, sotalol, nifedipine and mexiletine) and chemotherapeutics (tamoxifen, nilotinib, sunitinib and doxorubicin) was tested at clinically relevant concentrations for effects on intracellular Ca 2+ transits after a short-term (30 minutes) exposure, and plasma membrane permeabilization and caspase 3/7 activation after a long-term (72 hours) exposure. Intracellular Ca2+ transits were monitored by fluorescent images taken with a high-speed camera in beating cardiomyocytes loaded with Cal520® Ca2+ dye, permeabilized plasma membrane (for dead-cell detection) was identified with live-stain DRAQ7TM nuclear dye and activation of caspase 3/7 was determined biochemically with the Caspase-Glo® 3/7 Assay kit. Multiple endpoints derived from Ca 2+ transits, including beat rate, calcium transit duration (CTD) measured at 30% or 90% from peak and corrected by inter-peak interval (IPI), along with CTD triangulation, beat rhythm, short- or long-term variability of CTD90 and IPI Poincaré plots, were used to assess drug effects on intracellular Ca2+ cycling and arrhythmogenicity. Increases in positive nuclear staining for DRAQ7TM and caspase 3/7 activity represented structural cardiotoxicity. We found that increased CTD triangulation, development of arrhythmic events and both the short- and long-term variability of CTD90 or IPI were robust indicators of functional effects. Positive nuclear staining for DRAQ7TM was a robust indicator of structural effects. Accordingly, dofetilide and sotalol were identified as primarily arrhythmogenic, doxorubicin was primarily structurally toxic, while nilotinib and sunitinib were both arrhythmogenic and structurally toxic. The use of these endpoints in a single plate format simplifies the cardiotoxicity assessment and does not require multiple cell plates for measurements

Effects of Astragalus Polysaccharide on Immune Responses of Porcine PBMC Stimulated with PRRSV or CSFV

BACKGROUND: Astragalus polysaccharide (APS) has been used as an immunomodulator that can enhance immune responses, whereas the immunomodulatory effects of APS on porcine peripheral blood mononuclear cells (PBMCs) exposed to porcine reproductive and respiratory syndrome virus (PRRSV) and classical swine fever virus (CSFV) have not been investigated. METHODOLOGY/PRINCIPAL FINDINGS: Porcine PBMCs were cultured in complete RPMI media in the presence of the R98-strain of PRRSV (5×10(4) TCID(50)/ml) or C-strain of CSFV (10(3) TCID(50)/ml) with or without APS. The expression of mRNA for CD28, cytotoxic T-lymphocyte antigen 4 (CTLA-4), transforming growth factor-β (TGF-β), interleukin 2 (IL-2) and IL-10 was assayed by TaqMan real-time RT-PCR. The expression of mRNA for CD28 and CTLA-4 increased at 24 h after stimulation of PBMCs with CSFV and the increased production of CTLA-4 was confirmed by western blot analysis, whereas the increases were inhibited by the addition of APS. In addition, APS alone upregulated IL-2 and TGF-β mRNA expression in PBMCs and the addition of APS had the capacity to prevent a further increase in IL-2 mRNA expression in PBMCs during CSFV or PRRSV infection, but had no effect on TGF-β mRNA expression. The production of tumor necrosis factor-alpha (TNF-α) increased at 12 h after stimulation with PRRSV or CSFV, but not with PRRSV plus APS or CSFV plus APS, whereas the addition of APS to PBMCs infected with PRRSV or CSFV promoted IL-10 mRNA expression. CONCLUSIONS: We suggested that APS had immunomodulatory effects on cells exposed to PRRSV or CSFV. It might be that APS via different mechanisms affects the activities of immune cells during either PRRSV or CSFV infection. This possibility warrants further studies to evaluate whether APS would be an effective adjuvant in vaccines against PRRSV or CSFV