• KSTLE International Journal
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• v.6 no.1
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• pp.8-12
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• 2005

The electrorheological properties pertaining to the electrorheological (ER) bebaviour of chitin and chitosan suspensions in silicone oil were investigated. Chitosan suspension showed a typical ER response (Bingham flow behavior) upon application of an electric field, while chitin suspension acted as a Newtonian fluid. The difference in behaior results from the difference in the conductivity of the chitin and chitosan particles, even though they have a similar chemical structure. The shear stress for the chitosan suspension exhibited a linear dependence on the volume fraction of particles and a 1.18 power of the electric field. The experimental results for the chitosan suspension correlated with the conduction model for ER response.

• Geotechnical Engineering
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• v.12 no.5
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• pp.63-78
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• 1996

Various type of in-situ and laboratary tests were performed in order to evaluate the stiffness of sedimentary soft rock. In triaxial compression tests of sedimentary soft rocks, axial strains from the axial displacement of the loading piston or specimen cap conventionally were considerably larger than those measured. tocally on the lateral surfaces of specimen, due to the bedding errors at the top and bottom ends of a specimen. A local deformation transducer was used to measure axial strains free from the bedding error ranging from 0.001% to about 1%. In ultra-sonic wave tests, the elastic modulus of unconfined spec imens was smaller than that of confined specimens, due probably to microfracks. Young's modulus Ed from ultra-sonic wave tests and those at small local strains from triaxial tests were similar, both of which agreed very well with Young's modulus Er from field shear wave velocities. Young'a modulus from the field behaviour was virtually similar to that obtained by reducing Er based on the strain level-dependency of stiffness evaluated by the triaxial tests.

• Journal of the Korean Ceramic Society
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• v.46 no.5
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• pp.525-527
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• 2009

This paper presents a study on the magnetic behaviour of selected doped SiAlONs with various compositions including Y, Yb, Sm, Gd, and Er. The resulting crystalline phases were confirmed by X-ray diffraction. The magnetic hysteresis data for the samples were collected at room temperature using a vibrating sample magnetometer. The study revealed that doped SiAlONs experience an appreciable level of magnetic hysteresis. Although the parameters corresponding to hysteresis loops in doped SiAlONs are less than those of common ferrites, their magnetic properties of SiAlONs may open up new potential areas of application as the host SiAlON ceramics have excellent structural properties.

• Smart Structures and Systems
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• v.2 no.1
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• pp.61-80
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• 2006

The concept of structural vibration control is to absorb vibration energy of the structure by introducing auxiliary devices. Various types of structural vibration control theories and devices have been recently developed and introduced into mechanical systems. One of such devices is damper employing controllable fluids such as ElectroRheological (ER) or MagnetoRheological (MR) fluids. MagnetoRheological (MR) materials are suspensions of fine magnetizable ferromagnetic particles in a non-magnetic medium exhibiting controllable rheological behaviour in the presence of an applied magnetic field. This paper presents the modelling of an MRfluid damper. The damper model is developed based on Newtonian shear flow and Bingham plastic shear flow models. The geometric parameters are varied to get the optimised damper characteristics. The numerical analysis is carried out to estimate the damping coefficient and damping force. The analytical results are compared with the experimental results. The results confirm that MR damper is one of the most promising new semi-active devices for structural vibration control.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.17
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• pp.7819-7824
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• 2015

Purpose: To subtype breast cancer (BC) in Saudi women according to the recent molecular classification and to correlate these subtypes with available clinicopathological parameters. Materials and Methods: Estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor (Her2/neu) immunostaining was semi-quantitatively assessed to define molecular subtypes of luminal A and B, HER-2 and triple negative (basal-like) in BC paraffin embedded sections from 115 Saudi female patients diagnosed between 2005 to 2015 at the Department of Pathology, King Fahd Hospital, Almadinah, Saudi Arabia. Results: The most common subtypes were luminal A (47%), followed by luminal B (27.8%) and basal like subtypes (18.3%), whereas HER-2 was the least common subtype (6.9%). Luminal A was predominantly found in the old age group, with low tumor grade (p<0.001) and small tumor size, whereas HER-2 and basal-like subtypes were significantly associated with young age, high tumor grade, lymph node metastasis and lymphovascular invasion (p<0.03, 0.004, 0.05 and 0.04 respectively). All subtypes showed advanced clinical stage at the time of presentation. Conclusions: Molecular subtypes of Saudi BC patients in Almadinah region are consistent with most of the worldwide subtyping. The biological behaviour of each molecular subtype could be expected based on its characteristic clinicopathological features. Along with other prognostic indicators, molecular subtyping would be helpful in predicting prognosis and management of our BC patients. We recommend screening and early diagnosis of BC in our population.

• Korean Journal of Metals and Materials
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• v.49 no.3
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• pp.221-230
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• 2011

The cold spray process is an emerging technology that utilizes high velocity metallic particles for surface coating. Metallic powder particles are injected into a converging-diverging de Laval nozzle and accelerated to a high velocity by a supersonic gas flow. The cold spray process normally uses a circular nozzle that has a rather narrow spraying range. To overcome this fault, a slit nozzle was considered in this study. The slit nozzle is anticipated to reduce the coating process time because it has a wider coating width than the circular nozzle. However, the slit nozzle can reduce the coating efficiency because it does not allow as much gas and particle velocity as the circular nozzle. To improve the coating efficiency of a slit nozzle, the shape of the slit nozzle was modified. And the results of gas flow and particle behaviour according to the nozzlers shape were compared by the a numerical analysis. As a results, as Expansion Ratio(ER) of 7.5 was found to be the most optimal condition for enhancing the spraying efficiency when the ER was changed by the variation of nozzle neck and exit size.

• Smart Structures and Systems
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• v.1 no.3
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• pp.235-256
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• 2005

The non-linear behaviour of electrorheological (ER) and magnetorheological (MR) dampers makes it difficult to design effective control strategies, and as a consequence a wide range of control systems have been proposed in the literature. These previous studies have not always compared the performance to equivalent passive systems, alternative control designs, or idealised active systems. As a result it is often impossible to compare the performance of different smart damper control strategies. This article provides some insight into the relative performance of two MR damper control strategies: on/off control and feedback linearisation. The performance of both strategies is benchmarked against ideal passive, semi-active and fully active damping. The study relies upon a previously developed model of an MR damper, which in this work is validated experimentally under closed-loop conditions with a broadband mechanical excitation. Two vibration isolation case studies are investigated: a single-degree-of-freedom mass-isolator, and a two-degree-of-freedom system that represents a vehicle suspension system. In both cases, a variety of broadband mechanical excitations are used and the results analysed in the frequency domain. It is shown that although on/off control is more straightforward to implement, its performance is worse than the feedback linearisation strategy, and can be extremely sensitive to the excitation conditions.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.9739-9745
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• 2014

Purpose: We aimed to evaluate the effects of hormone receptor, HER2, and epidermal growth factor receptor (EGFR) expression on epithelial ovarian cancer (EOC) prognosis and investigate whether or not phenotypic subtypes might exist. Materials and Methods: The medical records of 82 patients who were diagnosed with EOC between 2003 and 2012 and treated by platinum-based chemotherapy were retrospectively evaluated. Expression of EGFR, oestrogen (ER), progesterone (PR), and cerbB2 (HER2) receptors were assessed immunohistochemically on paraffin-embedded tissues of these patients. Three phenotypic subtypes were defined according to ER, PR, and HER2 expression and associations of these with EGFR expression, clinicopathologic features, platinum sensitivity, and survival were investigated. Results: When we classified EOC patients into three subtypes, 63.4% had hormone receptor positive (HR(+)) (considering breast cancer subtypes, luminal A), 18.3% had triple negative, and 18.3% had HER2(+) disease. EGFR positivity was observed in 37 patients (45.1%) and was significantly more frequent with advanced disease (p=0.013). However, no significant association with other clinicopathologic features and platinum sensitivity was observed. HER2(+) patients had significantly poorer outcomes than HER2(-) counterparts (triple negative and HR positive patients) (p=0.019). Multivariate analysis demonstrated that the strongest risk factor for death was residual disease after primary surgery. Conclusions: Triple negative EOC may not be an aggressive phenotype as in breast cancer. The HER2 positive EOC has more aggressive behaviour compared to triple negative and HR(+) phenotypes. EGFR expression is more frequent in advanced tumours, but is not related with poorer outcome. Additional ovarian cancer molecular subtyping using gene expression analysis may provide more reliable data.

• Smart Structures and Systems
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• v.14 no.5
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• pp.901-916
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• 2014

Magnetorheological (MR) fluid is one of the field-responsive fluids that is of interest to many researchers due to its high yield stress value, which depends on the magnetic field strength. Similar to electrorheological (ER) fluid, the combination of working modes is one of the techniques to increase the performance of the fluids with limited focus on MR fluids. In this paper, a novel MR testing cell incorporated with valve, shear and squeeze operational modes is designed and constructed in order to investigate the behaviour of MR fluid in combined mode. The magnetic field distribution in the design concept was analyzed using finite element method in order to verify the effective areas of each mode have the acceptable range of flux density. The annular gap of valve and shear were fixed at 1 mm, while the squeeze gap between the parallel circular surfaces was varied up to 20 mm. Three different coil configurations, which were made up from 23 SWG copper wires were set up in the MR cell. The simulation results indicated that the magnetic field distributed in the squeeze gap was the highest among the other gaps with all coils were subjected to a constant applied current of 1 A. Moreover, the magnetic flux densities in all gaps were in a good range of magnitude based on the simulations that validated the proposed design concept. Hence, the 3D model of the MR testing cell was designed using Solidworks for manufacturing processes.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.8
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• pp.3897-3901
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• 2016

Background: Breast cancer is by far the most frequent cancer of women (23% of all cancers), ranking second overall when both sexes are considered together. Since there has been change in clinico-pathological factors and treatment profiles for breast cancer patients over the years, the present study to evaluate the change trends in India. Materials and Methods: A detailed analysis was carried out with respect to age, menopausal status, family history, disease stage, surgery performed, histopathology, hormone receptor status, and use of chemotherapy or hormonal therapy. Change in various clinico-pathological factors and treatments of breast cancer cases was recorded and analysed. Results: Mean age at presentation was found to be earlier in 2005-2006 compared with 1997-98 (p value: 0.046). More premenopausal women were diagnosed with breast cancer in 2005-2006 when this was compared with initial years of assessment (p value ${\leq}0.001$). When change in the receptor status was evaluated, we observed that there was a decrease in cases of ER and PR receptor positivity which was significant (p value: 0.007). Over the period of time, more f patients were not offered surgery initially in view of advanced disease when the two time periods were compared (p value: ${\leq}0.001$). There was a significant increase in patients who were initially offered neo-adjuvant chemotherapy in view of advanced disease at presentation (p value: ${\leq}0.001$). There was increasing number of patients who received palliative treatment for symptoms in 2005-2006 when compared to patients treated in 1997-98((p value: ${\leq}0.001$). Conclusions: Changes in mean age at presentation, premenopausal status, and stage at presentation have occurred over the years. More aggressive patterns of disease have become more common with early age at presentation and aggressive biological behaviour with receptor negative tumours.