Scanning laser source and scanning laser detection techniques for different surface crack geometries

Standard test samples typically contain simulated defects such as slots machined normal to the surface. However, real defects will not always propagate in this manner; for example, rolling contact fatigue on rails propagates at around 25º to the surface, and corrosion cracking can grow in a branched manner. Therefore, there is a need to understand how ultrasonic surface waves interact with different crack geometries. We present measurements of machined slots inclined at an angle to the surface normal, or with simple branched geometries, using laser ultrasound. Recently, Rayleigh wave enhancements observed when using the scanning laser source technique, where a generation laser is scanned along a sample, have been highlighted for their potential in detecting surface cracks. We show that the enhancement measured with laser detector scanning can give a more significant enhancement when different crack geometries are considered. We discuss the behaviour of an incident Rayleigh wave in the region of an angled defect, and consider mode-conversions which lead to a very large enhancement when the detector is close to the opening of a shallow defect. This process could be used in characterising defects, as well as being an excellent fingerprint of their presence

Non-contact ultrasonic detection of angled surface defects

Non-destructive testing is an important technique, and improvements are constantly needed. Surface defects in metals are not necessarily confined to orientations normal to the sample surface; however, much of the previous work investigating the interaction of ultrasonic surface waves with surface-breaking defects has assumed cracks inclined at 90° to the surface. This paper explores the interaction of Rayleigh waves with cracks which have a wide range of angles and depths relative to the surface, using a non-contact laser generation and detection system. Additional insight is acquired using a 3D model generated using finite element method software. A clear variation of the reflection and transmission coefficients with both crack angle and length is found, in both the out-of-plane and in-plane components. The 3D model is further used to understand the contributions of different wavemodes to B-Scans produced when scanning a sample, to enable understanding of the reflection and transmission behaviour, and help identify angled defects. Knowledge of these effects is essential to correctly gauge the severity of surface cracking

Establishment and characterization of two human breast carcinoma cell lines by spontaneous immortalization: Discordance between Estrogen, Progesterone and HER2/neu receptors of breast carcinoma tissues with derived cell lines

Background: Breast cancer is one of the most common cancers among women throughout the world. Therefore, established cell lines are widely used as in vitro experimental models in cancer research.Methods: Two continuous human breast cell lines, designated MBC1 and MBC2, were successfully established and characterized from invasive ductal breast carcinoma tissues of Malaysian patients. MBC1 and MBC2 have been characterized in terms of morphology analysis, population doubling time, clonogenic formation, wound healing assay, invasion assay, cell cycle, DNA profiling, fluorescence immunocytochemistry, Western blotting and karyotyping.Results: MBC1 and MBC2 exhibited adherent monolayer epithelial morphology at a passage number of 150. Receptor status of MBC1 and MBC2 show (ER+, PR+, HER2+) and (ER+, PR-, HER2+), respectively. These results are in discordance with histopathological studies of the tumoral tissues, which were triple negative and (ER-, PR-, HER2+) for MBC1 and MBC2, respectively. Both cell lines were capable of growing in soft agar culture, which suggests their metastatic potential. The MBC1 and MBC2 metaphase spreads showed an abnormal karyotype, including hyperdiploidy and complex rearrangements with modes of 52-58 chromosomes per cell.Conclusions: Loss or gain in secondary properties, deregulation and specific genetic changes possibly conferred receptor changes during the culturing of tumoral cells. Thus, we hypothesize that, among heterogenous tumoral cells, only a small minority of ER+/PR+/HER2+ and ER+/PR-/HER2+ cells with lower energy metabolism might survive and adjust easily to in vitro conditions. These cell lines will pave the way for new perspectives in genetic and biological investigations, drug resistance and chemotherapy studies, and would serve as prototype models in Malaysian breast carcinogenesis investigations. © 2012 Kamalidehghan et al.; licensee BioMed Central Ltd

Scanning laser techniques for characterisation of different surface breaking defect geometries

Measurements using a laser scanning system consisting of a pulsed Nd:YAG laser to generate surface ultrasonic waves and an interferometer to detect the surface displacement, are presented for different samples and defect geometries. We show, firstly, details of the interaction of Rayleigh waves in thick samples with machined slots inclined at an angle to the surface normal, or with simple branched geometries, scanning the generation source over the defect (SLLS) or scanning the detection point over the defect (SLD). Secondly, we discuss effects of Lamb waves interacting with V-shaped defects in thin samples. The results from these measurements have shown that the signal enhancement found in the near-field in both cases can be used to position the defect and gain an idea of its geometry, and have shown this to be a suitable fingerprint of the presence of the defect

Investigation of the Effects of Inlet System Configuration on the Airflow Characteristics

The effort towards the development of an engine that is efficient and green has become one of the biggest efforts of the major part of the automotive industry. The contribution of air quality to the engine plays an important role to increase power while minimizing the exhaust emission. The main purpose of this article is to investigate the characteristic of the air intake system of a naturally aspirated engine on a steady flow bench. The experiment was conducted using an industrial flow bench apparatus where the pressure different test pressures can be set and, at every test pressure, the valve is lifted at an increment of 1mm until the maximum possible valve lift where the flow rate is obtained in terms of cubic foot per minute or CFM. The experiment process was then repeated at different configuration. The experimental result shows that the flow rate increases with each valve lift in a linear pattern until at a certain point where the value becomes constant. The result also indicated that the flow rate increases as the different pressure increases

Hydrodynamic performance of a biomimetically improved tidal turbine blade

This paper contributes into the investigations on the feasibility of improving the performance of a marine current turbine using a biomimetic concept inspired from the leading edge tubercles at the flippers of humpback whales. An experimental test campaign has been recently conducted in the Emerson Cavitation Tunnel at Newcastle University and some details of this test campaign together with the findings are summarised in the paper. A set of tidal turbines with different leading-edge profiles was manufactured and tested to evaluate the effect on the hydrodynamic performance. Various tests, which included performance, flow observations, noise and cavitation, were conducted under different speed and different pitch angle settings of the turbine blades. Eventually, by these investigations, the advantage and disadvantage of applying the leading-edge tubercles on the hydrodynamic performance of the tidal turbines were evaluated as well as further understanding of this biomimetic concept in applying on to tidal turbines. As far as the performance tests are concerned, the results showed that the models with the leadingedge tubercles had a better performance in the lower tip speed ratios (TSRs) and at lower pitch angle settings where the turbine blades were working under the stall conditions. Furthermore, the tubercles have enabled to start the turbines quicker at very low TSR range. In the meanwhile the biomimetic concept did not compromise the maximum power coefficient value of the turbine without the tubercles but shifted the distribution of the coefficient over the range of the tip speed ratios tested

Effects of Pilot Injection Timing and EGR on a Modern V6 Common Rail Direct Injection Diesel Engine

Nitric oxide and smoke emissions in diesel engine can be controlled by optimising the air/fuel mixture and combustion temperature. Early in-cylinder diesel injection that produces premixed charge can simultaneously reduce NOx and smoke emissions. However, there could be an increase in hydrocarbons and CO emissions due to fuel impinged to the cylinder wall. The focus of the present work is on the effects of a variation of pilot injection timing with EGR to NOx and smoke level of a modern V6 common rail direct injection. This study is carried out at two different engine load conditions of 30 Nm and 55 Nm, at constant engine speed of 2000 rpm. Emissions of NOx are measured from the exhaust sample line by an exhaust gas analyzer (Horiba MEXA-7100EGR). Smoke level is measured by using an AVL 415S smoke meter which provides results directly as a Filter Smoke Number (FSN) unit. The results show that the early pilot injection timing contributed to the lower smoke level and higher NOx emissions. The higher level of NOx is due to higher combustion temperatures resulting from the complete combustion. Meanwhile, the lower smoke level is due to complete fuel combustion and soot oxidation. The early pilot injection timing produces an intermediate main ignition delay which also contributed to complete combustion. The formation of smoke is higher at a high engine load compared with low engine load is due to the higher amount of fuel being injected, resulting in higher smoke formatio

Planning and Implementation of the Bachelor of Education (Engineering) - The Open University Malaysia Experiences

This paper describes the process of designing and developing the curriculum of Bachelor of Education (Engineering) program at Open University Malaysia (OUM

Experimental investigations of the Hydro-Spinna turbine performance

A unique tidal turbine, “Hydro-Spinna”, is introduced. The Hydro-Spinna consists of three cardioidal blades spiralling around a common horizontal shaft. A 500 mm diameter model was manufactured and its performance investigated in the towing tank facility of Newcastle University. The main objective of these experiments was to investigate the hydrodynamic efficiency of Hydro-Spinna with a view to improve the design by collecting data for use in numerical optimization. Considering its flexible operating characteristics the model turbine was tested at different immersion depths and in the half-submerged condition. The power coefficient of the turbine reached a value of almost 0.3 at a tip speed ratio of 2.2 in the fully submerged condition. The turbine had a higher power coefficient in shallow immersion and half submerged condition. The drag coefficient on the whole system decreased with increasing TSR contrary to conventional turbines. The turbine was observed to start rotating at low flow velocities, down to 0.15 m/s. In the study, although the turbine presents a relatively low power coefficient compared to that of competitive turbines, its unique adaptability of immersion depth, including the partially submerged condition, low starting flow velocity and rotational speed offer an interesting prospect for a range of applications

Epidemiology and strain characterization of rotavirus diarrhea in Malaysia

SummaryObjectivesThe objectives of the study were to describe the epidemiology and strain characterization of rotavirus (RV), to determine the proportion of hospitalizations for diarrhea attributable to RV among children under 5 years of age, and to estimate the disease burden of RV diarrhea in Malaysia.MethodsAll children 0–59 months of age admitted for acute gastroenteritis to Kuala Lumpur Hospital (KLH) or Hospital Umum Sarawak (HUS) were surveyed. The periods of surveillance were from February 1, 2001 to April 30, 2003 in KLH and April 1, 2001 to March 31, 2003 for HUS.ResultsThe highest rate of RV-associated diarrhea was among children aged 6–17 months, accounting for 55% of RV-associated diarrhea. There was no seasonality observed in either hospital. P[8]G9 strains were predominant, accounting for 73% of all strains in both hospitals, 80% from KLH and 61% from HUS. There was no mortality.ConclusionsRV was responsible for 38% of hospitalizations for diarrhea. It was most common in the 6–17 months age group. There was no seasonality observed for RV-associated diarrhea. The most prevalent strain of RV was P[8]G9. The estimated incidence of RV-associated diarrhea was 27 per 10000 population under the age of 5 years per year