Modal analysis of high frequency acoustic signal approach for progressive failure monitoring in thin composite plates

During the past few decades, many successful research works have evidently shown remarkable capability of Acoustic Emission (AE) for early damage detection of composite materials. Modal Analysis of AE signals or Modal Acoustic Emission (MAE) offers a better theoretical background for acoustic emission analysis which is necessary to get more qualitative and quantitative result. In this paper, the application of MAE concept in a single channel AE source location detection method for failure characterization and monitoring in thin composite plates was presented. Single channel AE source location is one of the recent studies for composite early damage localization, owing to the growing interest and knowledge of modal analysis of AE wave. A tensile test was conducted for glass fiber epoxy resin specimen with small notch. A single channel of AE system was used to determine the AE source location on specimen under testing. The results revealed that AE single channel source location provides reasonable accuracy for glass fiber laminate which was tested

The time lag-luminosity relation: A consequence of the Amati relation?

We use a simple pulse model to investigate the origin of the time lagluminosity relation (LLR) discovered by Norris et al.(ApJ, 534 (2000) 248). We show that, at least for single pulse bursts which satisfy both the hardness-intensity and the hardness-fluence correlations, the LLR can be simply obtained as a consequence of the Amati relation

Quantitative (Non-qualitative) Changes of IgG Anti-Mumps After Freeze-‎Thaw Cycles

Object. The result of freeze-thaw (FT) tested sera is always doubtful, and is a matter of question which is accompanied by false negative results. Aim: To determine the effect of repeated FT cycles, on the assay results of mumps IgG antibody. Material and Methods. This prospective laboratory study includes 25 volunteers. 25 sera underwent tests for first Mumps IgG antibody, and then were frozen at -20 degrees centigrade. One week later, they were thawed and stored again at 4 degrees centigrade for one more week when the second assays, were performed. The results for mumps IgG ELISA as an effect of two FT cycles and storage temperature were reported. The results were recorded by first and second Immune Serum Ratio (ISR) value (for first and second assay) and the percentage change of ISR. A linear regression model applied for analyzing ISR change percentage. Results. There were three kinds of ISR value change as: 1-The stable ISR value (44%). 2-The decreasing change of ISR value (32%) mainly among males, older in age (14-19 years) and the first ISR more than the value of four. 3-The increasing change of ISR value (24%) which occurred in males 10-12 years with the first ISR value of 1-2 (lowest concentration). Based on regression model, level of the first ISR and group of test were significant factor for change percentage of ISR, but neither gender nor age, were significant. Discussions. Mumps IgG antibody , as a function of two FT cycles, was affected by quantitative but not qualitative alteration. If the first ISR has value of 3-4, most probably it wills no any significant changes due to at least two FT cycles

Overexpression of microRNA-16 declines cellular growth, proliferation and induces apoptosis in human breast cancer cells

MicroRNAs (miRNA) are a large family of small single-stranded RNA molecules found in all multicellular organisms. Early studies have been shown that miRNA are involved in cancer development and progression, and this role can be done by working as an oncogenes and tumor suppressor genes, so manipulation of this molecules can be a promising approach in cancer therapy, and experimental results represented that the modification in breast cancer phenotype is possible by miRNA expression alteration. miR-16, which is located in 13q14 chromosome, plays critical roles as a tumor suppressor by targeting several oncogenes which regulate cell cycle and apoptosis. Hence, in the present study, we investigated whether miR-16 could decline growth and survival of MCF-7 cell line as model of human breast cancer. MCF-7 cell line was infected with lentiviruses containing miR-16 precursor sequence. The effects of ectopic expression of miR-16 on breast cancer phenotype were examined by cell cycle analysis and apoptosis assays. miR-16 cytotoxicity effect was measured by the MTT assay. We showed that the miR-16 overexpression reduces Cyclin D1 and BCL2 at messenger RNA (mRNA) and protein levels in MCF-7 cell line. In addition, this is found that enforced expression of miR-16 decreases cell growth and proliferation and induces apoptosis in MCF-7 cells. In conclusion, our results revealed that upregulation of miR-16 would be a potential approach for breast cancer therapy. © 2015, The Society for In Vitro Biology

Development of fibre bragg grating (FBG) based pressure transducer with temperature compensation

In this work, an aluminium diaphragm fibre Bragg grating (FBG) pressure transducer with temperature compensation is been presented. FBG based sensors good for some applications such as pressure vessel, biomedical and combustion chamber. One of the greatest challenges for an FBG based transducer is the inconsistency in output wavelength due to temperature variations. This lead to huge variation pressure readings. In this study, two FBG are bonded on the diaphragm and base surface of the pressure transducer, respectively. The inconsistency of wavelength was eliminated by applying the temperature compensation technique. The result shows that this FBG pressure transducer has a sensitivity of 2.849 nm/MPa and a linear fitting coefficient of 99.97% in a pressure range from 0 to 0.2 MPa. This FBG pressure transducer is proven to be suitable for pressure measurement of gas or liquid with an average error of 1.97%

The lag and duration-luminosity relations of gamma-ray burst pulses

Relations linking the temporal or/and spectral properties of the prompt emission of gamma-ray bursts (hereafter GRBs) to the absolute luminosity are of great importance as they both constrain the radiation mechanisms and represent potential distance indicators. Here we discuss two such relations: the lag-luminosity relation and the newly discovered duration-luminosity relation of GRB pulses. We aim to extend our previous work on the origin of spectral lags, using the duration-luminosity relation recently discovered by Hakkila et al. to connect lags and luminosity. We also present a way to test this relation which has originally been established with a limited sample of only 12 pulses. We relate lags to the spectral evolution and shape of the pulses with a linear expansion of the pulse properties around maximum. We then couple this first result to the duration-luminosity relation to obtain the lag-luminosity and lag-duration relations. We finally use a Monte-Carlo method to generate a population of synthetic GRB pulses which is then used to check the validity of the duration-luminosity relation. Our theoretical results for the lag and duration-luminosity relations are in good agreement with the data. They are rather insensitive to the assumptions regarding the burst spectral parameters. Our Monte Carlo analysis of a population of synthetic pulses confirms that the duration-luminosity relation must be satisfied to reproduce the observational duration-peak flux diagram of BATSE GRB pulses. The newly discovered duration-luminosity relation offers the possibility to link all three quantities: lag, duration and luminosity of GRB pulses in a consistent way. Some evidence for its validity have been presented but its origin is not easy to explain in the context of the internal shock model.Comment: 8 pages, 5 figures, 1 tabl

A highly sensitive multiplexed FBG pressure transducer based on natural rubber diaphragm and ultrathin aluminium sheet

Pressure measurement with a good sensitivity has always been a concern in most of the engineering applications and biomedical field. In this paper, a multiplexed FBG bonded on an ultrathin aluminium sheet which act as a cantilever deflected due to a deformation from a natural rubber based diaphragm has been proposed and studied. By using two gratings inscribed on a single optical fibre which senses the positive and negative strain has enhanced the sensitivity of the pressure transducer recorded at 329.56 pm/kPa or corresponding to 10.7893 kPa−1 across the range of 0 to 10 kPa with a good linearity of 99.76%. Furthermore, the thermal cross-sensitivity is compensated