381 research outputs found

    Understanding the Charge Carrier Conduction Mechanisms of Plasma-Polymerized 2-Furaldehyde Thin Films via DC Electrical Studies

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    Monomer 2-furaldehyde (FDH) was deposited onto the glass substrates in optimum conditions via a glow discharge using a capacitively coupled parallel plate reactor to obtain plasma polymerized 2-furaldehyde (PPFDH) thin films of different thicknesses. In order to realize the carrier conduction mechanisms, the direct current density against applied voltage (J-V) characteristics of these films with different thicknesses were investigated at different temperatures (T) in the voltage region from 0.5 to 49 V in Al/PPFDH/Al sandwich configuration. The J-V characteristics at various temperatures follow a power law of the form J ∞ Vn. In the low voltage region the values of n were recorded to be 0.80 ≤ n ≤ 1.12 and those in the high voltage region found to lie between 1.91 ≤ n ≤ 2.58, demonstrating the Ohmic conduction mechanism in the low voltage region and non-Ohmic conduction in the high voltage region. Theoretically calculated and experimental results of Schottky (βs) and Poole-Frenkel (βPF) coefficients display that the most probable conduction mechanism in PPFDH thin films is the Schottky type. Arrhenius plots of J vs. 1/T for an applied voltage of 5 V, the activation energies were 0.13 ± 0.02 and 0.50 ± 0.05 eV in the low and high temperature regions, respectively. However, for an applied voltage of 35 V, the activation energy values were found to be 0.11 ± 0.01 eV and 0.55 ± 0.02 eV, respectively in low and high temperature regions

    Hydrodynamic Characteristics of 30 GT Fishing Ship Hull Form in Sulawesi Waters

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    This study aims to determine the hydrodynamic characteristics of the 30 GT fishing ship hull form, operating around Sulawesi waters. The hydrodynamic study includes determinations of; i) ship main dimensions, ii) ship resistance and power, iii) ship stability and maneuvering. The main dimensions identifications were based on a several fishing ship. Ship resistance and power aproximination used Holtrop method. The investigation of ship stability and maneuvering was based on the IMO criteria. Three samples of the fishing ship were investigated. The results of the hydrodynamic analysis showed that the influences of B/T ratio is significant. Properly selecting the B/T ratio on fishing ships can be improved in power reduction and possible increase in safety of shi

    Hydrodynamic Characteristics of 30 GT Fishing Ship Hull Form in Sulawesi Waters

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    This study aims to determine the hydrodynamic characteristics of the 30 GT fishing ship hull form, operating around Sulawesi waters. The hydrodynamic study includes determinations of; i) ship main dimensions, ii) ship resistance and power, iii) ship stability and maneuvering. The main dimensions identifications were based on a several fishing ship. Ship resistance and power aproximination used Holtrop method. The investigation of ship stability and maneuvering was based on the IMO criteria. Three samples of the fishing ship were investigated. The results of the hydrodynamic analysis showed that the influences of B/T ratio is significant. Properly selecting the B/T ratio on fishing ships can be improved in power reduction and possible increase in safety of shi

    Heat treatment effect on the structural, morphological, and optical properties of plasma polymerized furan-2-carbaldehyde thin films

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    The furan-2-carbaldehyde (PPFCD) amorphous polymer thin films, with several thicknesses, were deposited onto glass substrates using a glow discharge of monomer FCD at ordinary room temperature via plasma polymerization technique. The structural, morphological, and optical characteristics of the as synthesised PPFCD amorphous films were studied as a function of temperature via X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and ultraviolet-visible (UV–Vis) absorption spectroscopy. The amorphous nature of the thin films was ascertained in both as-synthesised and heat treated states using the XRD studies. The SEM micrographs display homogeneous and fracture free surface of PPFCD films and no remarkable variation in the surface morphology of the as synthesised films was detected owing to the heat treatment procedure. However, the EDX, and FTIR analysis represented some structural rearrangement originated from the heat treatment of the PPFCD thin films. The analysis of the UV–Vis absorption spectroscopy revealed that the absorbance of the films depend on the films thickness and the temperature of the heat treatment. The optical band-gaps of PPFCD amorphous films were found to be significantly decreased with the gradual rise in heat treatment temperature

    Structural and optical properties of plasma polymerized pyromucic aldehyde thin films

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    Abstract: Plasma polymerized pyromucic aldehyde (PPPA) thin films have been deposited on to glass substrates by glow discharge technique. Scanning electron microscopy (SEM) graphs reveal that the surface morphology of PPPA thin films is uniform and flawless. FTIR analysis reveals that the chemical composition of PPPA films is different from that of the pyromucic aldehyde (PA). From the UV-vis spectra direct and indirect transition energy gaps were determined for as deposited PPPA thin films of different thicknesses

    Fresh state and hydration properties of high-volume lithium slag cement composites

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    In this study, the fresh state and hydration properties of 0–60% lithium slag blended cement pastes were investigated at water-binder ratio of 0.47. The workability of the fresh pastes was evaluated by measuring the air content, marsh cone flow, mini-slump flow, setting times, and through rheology tests. A 40% lithium slag cement could produce 91% strength activity index at 28 days; mini-slump pat diameter of 70.54 mm; marsh cone flow efflux time of 145 s; air content 0.6%; hydration heat of 300 J/g (at 72 h). At replacement levels above 40%, the strength activity index, air content, mini-slump flow, hydration heat, and fluidity were significantly reduced. Experimental investigations confirm that the mini-slump test provides the best correlation coefficients (R 2 = 0.96) with the maximum shear viscosity of lithium slag cement pastes than the marsh cone flow efflux time and air content. The classical slump and rheological models were used to characterise the mini-slump, yield stress, and plastic viscosity of low to high volume lithium slag cement pastes. The present study recommends that a 40% lithium slag cement paste is a viable option to produce green concrete for optimum fresh, hydration, rheological, and hardened properties

    Control Chart Pattern Recognition Using Small Window Size for Identifying Bivariate Process Mean Shifts

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    There are many traits in the manufacturing technology to assure the quality of products. One of the current practices aims for monitoring the in-process quality of small-lot production using Statistical Process Control (SPC), which requires small samples or small window sizes. In this study, the recognition performance of bivariate SPC pattern recognition scheme was investigated when dealing with small window sizes (less than 24). The framework of the scheme was constructed using an artificial neural network recognizer. The simulated SPC samples in different window sizes (8 ~ 24) and different change points (fixed and varies) were generated to study the recognition performance of the scheme based on mean square error (MSE) and classification accuracy (CA) measures. Two main findings have been suggested: (i) the scheme was superior when recognizing shift patterns with various change points compared to the shift patterns with fixed change point, with lower MSE and higher CA results, (ii) the scheme was more difficult to recognize smaller window size patterns with increasing MSE and decreasing CA trends, since these patterns provided insufficient information of unnatural variation. The outcome of this study would be helpful for industrial practitioners towards applying SPC for small-lot-production. &nbsp

    Control Chart Pattern Recognition Using Small Window Size for Identifying Bivariate Process Mean Shifts

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    There are many traits in the manufacturing technology to assure the quality of products. One of the current practices aims for monitoring the in-process quality of small-lot production using Statistical Process Control (SPC), which requires small samples or small window sizes. In this study, the recognition performance of bivariate SPC pattern recognition scheme was investigated when dealing with small window sizes (less than 24). The framework of the scheme was constructed using an artificial neural network recognizer. The simulated SPC samples in different window sizes (8 ~ 24) and different change points (fixed and varies) were generated to study the recognition performance of the scheme based on mean square error (MSE) and classification accuracy (CA) measures. Two main findings have been suggested: (i) the scheme was superior when recognizing shift patterns with various change points compared to the shift patterns with fixed change point, with lower MSE and higher CA results, (ii) the scheme was more difficult to recognize smaller window size patterns with increasing MSE and decreasing CA trends, since these patterns provided insufficient information of unnatural variation. The outcome of this study would be helpful for industrial practitioners towards applying SPC for small-lot-production. &nbsp

    Did salvage ICE chemotherapy improve the outcome in primary resistant/relapsing stage III/IV neuroblastoma?

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    AbstractBackground and purposeNeuroblastoma is the most common extracranial and deadly solid tumor in children. It accounts for 15% of the deaths from cancer in the pediatric age group. Approximately half of the newly diagnosed children are at “high risk” of treatment failure.The aim of this study is to evaluate the response rate of salvage chemotherapy by the ICE (Ifosfamide, Carboplatin, and Etoposide) regimen when administered to previously treated primary refractory or progressive high risk neuroblastoma patients.Patients and methodsSixty-six patients from the National Cancer Institute (NCI), Cairo University and the Children Cancer Hospital Egypt (CCHE) received salvage chemotherapy (ICE) either due to primary resistance in 51/66 (77.2%) or due to disease progression on primary chemotherapy in 15/66 (22.8%).ResultsThey were 40 males (60.6%) and 26 females (39.4%). Patients’ age ranged between 3months and 12.5years. The most common tumor site was suprarenal, followed by retroperitoneal mass. Two patients (3%) died from chemotherapy toxicity during ICE administration. Evaluation of tumor response in the remaining 64 patients showed the following: CR/PR in 24 patients (36.5%), SD in 11 patients (16.6%), and PD in 29 patients (43.9%).Fourteen patients (21.2%) were considered eligible for auto BMT, while 50/64 patients (78.8%) failed this second line (salvage) chemotherapy and had palliative lines of therapy.By the end of the study (May 2010), 47/66 (71.2%) of the patients were still alive, while 19/66 (28.8%) were dead. Two out of 14 patients (14.2%) who underwent HSCT died from post transplantation disease progression, while 12/14 (85.8%) were in CCR.ConclusionChemotherapy by ICE for primary resistant or progressive stage III/IV NB seems well tolerated. With a 36.6% response rate, 18% CCR, and 3% treatment mortality rate, it could be considered a good salvage therapy in the category of patients who are condemned for palliation

    Validation of the Schizophrenia Quality of Life Scale Revision 4 among Chronic Schizophrenia Patients in Malaysia

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    Objectives: To explore the validity and reliability of a disease-specific health-related quality-of-life questionnaire-the Schizophrenia Quality of Life Scale Revision 4 (SQLS-R4)-in patients with schizophrenia in Malaysia. Methods:A total of 222 outpatients with schizophrenia receiving treatment at the Universiti Kebangsaan Malaysia Medical Centre completed the SQLS-R4 in either the Malay or the English language. A generic self-report health-related quality-of-life measure-the EuroQoL group EuroQol five-dimensional questionnaire-and a measure of symptom severity-the Clinical Global Impression-Schizophrenia scale-were also administered to assess validity. Results: Good internal consistency reliability was found for both the psychosocial and vitality domains (Cronbach's ? = 0.95 and 0.85, respectively). Most items were also significantly correlated with their own scale score (r s ranging from 0.29 to 0.74). There was a moderate correlation between the SQLS-R4 "vitality" domain and the EuroQol five-dimensional questionnaire "usual activities" domain (r s = 0.44) and a large correlation between the SQLS-R4 "psychosocial" domain and the EuroQol five-dimensional questionnaire "anxiety/depression" domain (r s = 0.44-0.57). Most of the symptom dimensions of the Clinical Global Impression-Schizophrenia scale were also moderately correlated with the SQLS-R4 subscale scores. Conclusions:The SQLS-R4 is a valid and reliable health-related quality-of-life instrument for use in minimally ill patients with schizophrenia in Malaysia, but some of the items may be redundant and irrelevant. Validation of SQLS-R4 in different types of patients and various levels of illness severity is required to further verify its application.Scopu
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