398 research outputs found
A review on applications of wavelet transform and artificial intelligence systems in fault diagnosis of rotating machinery
Experimental set-up for investigation of fault diagnosis of a centrifugal pump
Centrifugal pumps are complex machines which can experience different types of fault. Condition monitoring can be used in centrifugal pump fault detection through vibration analysis for mechanical and hydraulic forces. Vibration analysis methods have the potential to be combined with artificial intelligence systems where an automatic diagnostic method can be approached. An automatic fault diagnosis approach could be a good option to minimize human error and to provide a precise machine fault classification. This work aims to introduce an approach to centrifugal pump fault diagnosis based on artificial intelligence and genetic algorithm systems. An overview of the future works, research methodology and proposed experimental setup is presented and discussed. The expected results and outcomes based on the experimental work are illustrated
Effect of different alcohols on stratum corneum kallikrein 5 and phospholipase A2 together with epidermal keratinocytes and skin irritation
OBJECTIVES: The aim of this exploratory study was to investigate the effect of ethanol, isopropanol and n-propanol on stratum corneum (SC) enzymes and keratinocytes in vitro together with their effects on skin condition and function. METHODS: Activities of kallikrein 5 (KLK5) and phospholipase A2 (PLA2) as well as keratinocyte metabolic activity, interleukin-1α (IL-1α) and tumor necrosis factor-α (TNF-α) were measured in vitro in the presence and absence of the different alcohols. We also measured transepidermal water loss (TEWL), skin capacitance, visual dryness and visual redness on the volar forearms of 25 Caucasian women following application of the alcohols 20 and 100 times per day over a period of 14 days in a clinical study. RESULTS: Reduced activities of KLK5 and PLA2 were observed in the presence of the alcohols. The greatest denaturing effect was always observed for n-propanol (P  isopropanol > ethanol. At the high application frequencies, the effect of the different alcohols on transepidermal water loss (TEWL) and skin capacitance was similar, but at the low application frequencies, n-propanol had a significant effect on TEWL and capacitance values (P < 0.05). Equally, n-propanol and isopropanol produced significantly more skin redness at the low application frequencies. CONCLUSIONS: Clearly, isopropanol and n-propanol caused significant SC and keratinocyte perturbation in vitro together with damage to skin condition and function in vivo whereas ethanol did not. As a result, we show that ethanol-based sanitizers are better tolerated by skin, particularly in high-use settings, than other alcohols and should be the active ingredient of choice
Modelling and Simulation of Heterogeneous and Anisotropic Formations using Advanced Fractal Reservoir Models
Energy and carbon-efficient exploitation, management, and remediation of subsurface aquifers, gas and oil resources, CO2-disposal sites, and energy storage reservoirs all require high quality modelling and simulation. The heterogeneity and anisotropy of such subsurface formations has always been a challenge to modellers, with the best current technology not being able to deal with variations at scales of less than about 30-50 m. Most formations exhibit heterogeneities and anisotropy which result in variations of the petrophysical properties controlling fluid flow down to millimetre scale and below. These variations are apparent in well-logs and core material, but cannot be characterised in the inter-well volume which makes up the great majority of the formation.
This paper describes a new fractal approach to the modelling and simulation of heterogeneous and anisotropic aquifers and reservoirs. This approach includes data at all scales such that it can represent the heterogeneity of the reservoir correctly at each scale.
Advanced Fractal Reservoir Models (AFRMs) in 3D can be produced using our code. These AFRMs can be used to model fluid flow in formations generically to understand the effects of an imposed degree of heterogeneity and anisotropy, or can be conditioned to match the characteristics of real aquifers and reservoirs. This paper will show how 3D AFRMs can be created such that they represent critical petrophysical parameters, as well as how fractal 3D porosity and permeability maps, synthetic poro-perm cross-plots, water saturation maps and relative permeability curves can all be calculated. It will also show how quantitative controlled variation of heterogeneity and anisotropy of generic models affects fluid flow. We also show how AFRMs can be conditioned to represent real reservoirs, and how they provide a much better simulated fluid flow than the current best technology.
Results of generic modelling and simulation with AFRMs show how total hydrocarbon production, hydrocarbon production rate, water cut and the time to water breakthrough all depend strongly on heterogeneity, and also depend upon anisotropy. Modelling with different degrees and directions of anisotropy shows how critical hydrocarbon production data depends on the direction of the anisotropy, and how that changes over the lifetime of the reservoir.
Advanced fractal reservoir models are of greatest utility if they can be conditioned to represent individual reservoirs. We have developed a method for matching AFRMs to aquifer and reservoir data across a wide range of scales that exceeds the range of scales currently used in such modelling. We show a hydrocarbon production case study which compares the hydrocarbon production characteristics of such an approach to a conventional krigging approach. The comparison shows that modelling of hydrocarbon production is appreciably improved when AFRMs are used, especially if heterogeneity and anisotropy are high. In this study AFRMs in moderate to high heterogeneity reservoirs always provided results within 5% of the reference case, while the conventional approach resulted in massive systematic underestimations of production rate by over 70%
Methanol-to-hydrocarbons conversion over MoO3/H-ZSM-5 catalysts prepared via lower temperature calcination: a route to tailor the distribution and evolution of promoter Mo species, and their corresponding catalytic properties
A series of MoO3/H-ZSM-5 (Si/Al=25) catalysts were prepared via calcination at a lower-than-usual temperature (400 oC) and subsequently evaluated in the methanol-to-hydrocarbon reaction at that same temperature. The catalytic properties of those catalysts were compared with the sample prepared at the more conventional, higher temperature of 500 oC. For the lower temperature preparations, molybdenum oxide was preferentially dispersed over the zeolite external surface, while only the higher loading level of MoO3 (7.5 wt% or higher) led to observable inner migration of the Mo species into the zeolite channels, with concomitant partial loss of the zeolite Brønsted acidity. On the MoO3 modified samples, the early-period gas yield, especially for valuable propylene and C4 products, was noticeably accelerated, and is gradually converted into an enhanced liquid aromatic formation. The 7.5 wt% MoO3/H-ZSM-5 sample prepared at 400oC thereby achieved a balance between the zeolite surface dispersion of Mo species, their inner channel migration and the corresponding effect on the intrinsic Brønsted acidity of the acidic zeolite. That loading level also possessed the highest product selectivity (after 5h reaction) to benzene, toluene and xylenes, as well as higher early-period valuable gas product yields in time-on-stream experiments. However, MoO3 loading levels of 7.5wt% and above also resulted in earlier catalyst deactivation by enhanced coke accumulation at, or near, the zeolite channel openings. Our research illustrates that the careful adoption of moderate/lower temperature dispersion processes for zeolite catalyst modification gives considerable potential for tailoring and optimizing the system’s catalytic performanc
Effects of the solar eclipse on 15 January 2010 on the surface O3, NO, NO2, NH3, CO mixing ratio and the meteorological parameters at Thiruvanathapuram, India
In this paper, we present the effect of total solar eclipse on surface O3, NO, NO2, NH3, CO mixing ratio and the meteorological parameters on 15 January 2010 at Thiruvanathapuram, India. On the day of total solar eclipse
(i.e., 15 January 2010), the decrease in mixing ratio of surface O3 and NO2 is observed after the beginning of the solar eclipse events (11:15 to 15:30). Decrease in surface O3 may be due to decreased efficiency of the photochemical ozone formation, whereas, mixing ratio of NO and NH3 have been changed following the night time chemistry. Surface O3 reduced to 20.3 ppb after 22 min of full phase of the eclipse. During the solar eclipse period, the ambient temperature and wind speed have decreased, whereas, relative humidity has increased as expected
Religious faith and psychosocial adaptation among stroke patients in Kuwait: A mixed method study
This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2012 Springer Science+Business Media.Religious faith is central to life for Muslim patients in Kuwait, so it may influence adaptation and rehabilitation. This study explored quantitative associations among religious faith, self-efficacy, and life satisfaction in 40 female stroke patients and explored the influence of religion within stroke rehabilitation through qualitative interviews with 12 health professionals. The quantitative measure of religious faith did not relate to life satisfaction or self-efficacy in stroke patients. However, the health professionals described religious coping as influencing adaptation post-stroke. Fatalistic beliefs were thought to have mixed influences on rehabilitation. Measuring religious faith among Muslims through a standardized scale is debated. The qualitative accounts suggest that religious beliefs need to be acknowledged in stroke rehabilitation in Kuwait
Heritability of subcortical volumetric traits in mesial temporal lobe epilepsy.
OBJECTIVES: We aimed to 1) determine if subcortical volume deficits are common to mesial temporal lobe epilepsy (MTLE) patients and their unaffected siblings 2) assess the suitability of subcortical volumetric traits as endophenotypes for MTLE. METHODS: MRI-based volume measurements of the hippocampus, amygdala, thalamus, caudate, putamen and pallidium were generated using an automated brain reconstruction method (FreeSurfer) for 101 unrelated 'sporadic' MTLE patients [70 with hippocampal sclerosis (MTLE+HS), 31 with MRI-negative TLE], 83 unaffected full siblings of patients and 86 healthy control subjects. Changes in the volume of subcortical structures in patients and their unaffected siblings were determined by comparison with healthy controls. Narrow sense heritability was estimated ipsilateral and contralateral to the side of seizure activity. RESULTS: MTLE+HS patients displayed significant volume deficits across the hippocampus, amygdala and thalamus ipsilaterally. In addition, volume loss was detected in the putamen bilaterally. These volume deficits were not present in the unaffected siblings of MTLE+HS patients. Ipsilaterally, the heritability estimates were dramatically reduced for the volume of the hippocampus, thalamus and putamen but remained in the expected range for the amygdala. MRI-negative TLE patients and their unaffected siblings showed no significant volume changes across the same structures and heritability estimates were comparable with calculations from a healthy population. CONCLUSIONS: The findings indicate that volume deficits for many subcortical structures in 'sporadic' MTLE+HS are not heritable and likely related to acquired factors. Therefore, they do not represent suitable endophenotypes for MTLE+HS. The findings also support the view that, at a neuroanatomical level, MTLE+HS and MRI-negative TLE represent two distinct forms of MTLE
Association between Metabolic Disorders and Cholangiocarcinoma: Impact of a Postulated Risk Factor with Rising Incidence
Introduction and objectives: The incidence of cholangiocarcinoma (CCA) has been increasing globally. Although a concomitant increase in the incidence of metabolic disorders might suggest a causal relationship, the data are scarce. We aimed to describe the prevalence of metabolic disorders in patients with CCA and report the clinical features and outcomes. Patients and Methods: Retrospective study including patients with CCA. Patients were divided into: (1) past history of diabetes or/and overweight/obesity (“metabolic disorder group”) and (2) without any of these features (“non-metabolic-disorder group”). A Cox regression model was used to determine the prognostic factors. Results: 122 patients were included. In total, 36 (29.5%) had overweight/obesity, 24 (19.7%) had diabetes, and 8 (6.6%) had both. A total of 29 (23.8%) patients had resectable disease and received upfront surgery. A total of 104 (85.2%) received chemotherapy for advanced/recurrent disease. The overall survival of the cohort was 14.3 months (95% CI: 10.1–17.3). ECOG-PS 0 (p < 0.0001), resectable disease (p = 0.018) and absence of vascular invasion (p = 0.048) were independently associated with better prognosis. The “metabolic disorder group” (n = 52) had a median survival of 15.5 months (95% CI 10.9–33.9) vs. 11.5 months (95% CI 8.4–16.5) in the “non-metabolic-disorder group” (n = 70) (HR: 1.10; 95% CI 0.62–1.94). Patients with resectable disease in the “metabolic group” had longer survival than patients in the “non-metabolic group” (43.4 months (95% CI 33.9-NR) vs. 21.8 months (95% CI 8.6–26.9); HR = 0.12, 95% CI 0.03–0.59). Conclusion: Metabolic disorders are frequent among CCA patients. Underlying metabolic comorbidities may be associated with prognosis in resectable CCA. There is a need to explore the mechanism that drives CCA carcinogenesis in a metabolic background
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