Satellite data and real time stations to improve water quality of Lake Manzalah

AbstractThe objective of this study is to choose suitable approach for generating quantitative water quality products from Medium-Spectral Resolution Imaging Spectrometer (MERIS) imagery in near real-time. Four MERIS Case-II water processors included in the BEAM software package were studied for estimating the lake water quality. Chlorophyll-a (CHL), Turbidity (TUR) products of the BEAM processors were compared to in situ data. No statistically significant correlations were observed between in situ data and individual top-of-atmosphere (TOA) reflectances. By contrast, significant correlations were observed for the Band9/Band 7 ratio. Using uncorrected band ratios of TOA reflectances as input, coefficients of determination of 0.83 and 0.76 were obtained for TUR and CHL, respectively. The regression models for TUR and CHL were subsequently validated. The formulating regression models based on TOA reflectances is a valid approach to generate Earth Observation (EO) based water quality information in an operational setting. The results revealed that the empirical models estimated for TUR and CHL are more appropriate to generate water quality products from MERIS imagery

Electrohydrodynamic Kelvin-Helmholtz instability for a velocity stratified fluid

AbstractThe electrohydrodynamic stability of a conducting incompressible stratified fluid topping a dielectric fluid layer is studied. The stability of the system is discussed theoretically and numerically. It is found that the normal electric field has a destabilising effect while the increase of the thickness of the layer has a stabilising influence. The special case of the Rayleigh-Taylor instability is also examined

Aging changes in the retina of male albino rat: a histological, ultrastructural and immunohistochemical study

Background: Degenerative changes caused by aging may affect the eye, especially the retina. Such changes occur as a part of normal physiological process and may be irreversible. The aim of the study was to demonstrate the influence of aging on the morphology of the retina to provide a basis to explain the pathogenesis of age-associated decline in visual acuity, scotopic and photopic sensitivity.  Materials and methods: Forty male albino rats were used and divided into four age groups (group I: age of cortical maturity, group II: middle-aged, group III: aged group and group IV: senile group). The rats were sacrificed, the eye balls were enucleated. Intra-vitreal injections of formalin for haematoxylin and eosin and immunohistochemical sections, glutaraldehyde for toluidine blue semithin and E/M ultra-thin sections were performed. Measurements and quantitative histomorphometric estimation of the layers of the retina were done.  Results: Light microscopic examination revealed age-dependent attenuation of photoreceptor striations. Aged and senile groups presented pyknotic, widely- -spaced nuclei of the outer nuclear layer. The inner nuclear layer was thinned out to 2 or 3 cellular rows. Retinal capillaries showed progressive dilatation and congestion. Statistical analysis proved significant thinning of the retina with variable degrees of thinning of the constituting layers. Decreased arborisation with age was confirmed with quantification of synaptophysin-immunostained sections. Glial fibrillary acidic protein immunostaining revealed the picture of reactive gliosis. On the ultrastructural level, the retinal pigment epithelium exhibited major alterations with aging. Numerous phagosomes, lipofuscin and melanolipofusin granules appeared within the cells, together with exaggerated basal infoldings. The pho- toreceptor nuclei became degenerated and the perinuclear space was widened. Conclusions: Rat retinae clearly undergo age-related morphological changes. Such changes provide a cellular base for explanation of decreased vision in humans with aging other than reflection errors. Effect of aging was not only qualitative, but also quantitative

CRUDE OIL FOULING: PETRONAS REFINERIES EXPERIENCE

Managing crude oil fouling has been a challenge in PETRONAS refineries. Over the past several years, numerous initiatives have been conducted in order to have better control of the situation [1][2][3][4]. The control strategy currently implemented is to periodically clean the heat exchanger based on the heat exchanger monitoring parameter and supported by antifouling chemical injection program. A review was conducted in one of PETRONAS’ refineries in order to come up with a better fouling control strategy. The review is separated into two parts. Firstly, the plant operational data for two selected hot pre-heat exchanger trains was analyzed. From the analysis, deposition build-up is apparent for only one exchanger train despite both trains receiving the same crude blend. It seems that there are several significant parameters which caused one of the exchanger to fall into fouling threshold region. EXPRESS [5] software was used to evaluate the fouling threshold region for the heat exchanger. Secondly, foulant sample obtained from the heat exchangers were subjected to analytical testing to investigate the constituent of the foulant. The analyses show that it is mainly organic in nature with a minor portion of the inorganic content made up of mostly corrosion products, salt and sand

Influence of soda lime glass addition on the dielectric properties of CCTO ceramics

The dielectric properties of CCTO ceramics with soda-lime glass addition was investigated. The addition of soda lime glass was varied from 0 - 0.05 wt.% by solid-state reaction. Both XRD patterns of CCTO and CCTO-glass sintered samples showed the formation of CCTO phase with minor peaks of CuO phase, respectively. The phase area analysis of CCTO and CCTOglass proved that the CCTO phase was found to be decreased while the grain boundaries area of CuO + glass was then increased after the addition of soda-lime glass. The dielectric properties of corresponding samples indicated that both εr and tan δ were reduced with glass addition. Thus, it shows that the soda lime glass addition has a significant effect on dielectric properties of CCTO ceramics

Analysis of the oxypropylation process of a lignocellulosic material, almond shell, using the response surface methodology (RSM)

info:eu-repo/semantics/publishedVersio

Step and Step-Nc as a Tool for Big Data in Cloud Manufacturing

The terms big data, cloud manufacturing, predictive and additive manufacturing, and Internet of Things (IoT) are being most commonly used in the manufacturing industry nowadays. These terms are related to the fourth industrial revolution that emphasizes automation and data exchange between manufacturing tools/elements. Communication occurs between machines, products and even technicians or operators through various technologies while creating records of each interaction resulting in rapid growth of amount of data to be stored. Data acquisition is not a major issue since a structure or framework can properly connect these data in improving manufacturing efficiency. However, lack of effort in collecting and storing manufacturing data in the whole product life cycle process has made integration to be almost difficult to achieve. In this study, the adoption of STEP-NC method/technique was demonstrated in suiting the current explosion of big data in the industrial and manufacturing sector. The proposed methodology was developed through a study of an entity file structure and hierarchical concept in STEP and STEP-NC in gathering manufacturing data in a unified database. The challenge would be in making sense of the data, revealing the patterns in it and using them for operational improvements. The outcome of this study will be useful to support strategic decision making in product manufacturing

Propiedades magnéticas de los sedimentos de tipo estuarino. El caso de las Rías Baixas.

Este trabajo establece la utilidad de la susceptibilidad magnética como indicador de la influencia marina y evolución diagenética en sedimentos costeros de las Rías Baixas. Para ello se investigó la variabilidad geográfica de la susceptibilidad en 200 muestras de sedimentos marinos superficiales en las Rías de Vigo y Pontevedra. Su variabilidad vertical se estudió en 80 muestras de tres testigos de entre 60 y 90 cm de longitud extraídos en la Ría de Pontevedra. La susceptibilidad de las muestras superficiales aumenta progresivamente hacia mar abierto, y a medida que nos alejamos de las zonas de mayor influencia continental, estando relacionada con la textura y composición del sedimento, y por tanto, con su procedencia. Los testigos, más homogéneos litológicamente, mostraron una disminución muy importante de la susceptibilidad con la profundidad, estando ésta asociada a la evolución diagenética del sedimento. Para estudiar mejor estos procesos, se determinó la composición elemental y mineralógica, y además se midieron otras propiedades magnéticas de muestras representativas. Estos resultados se analizaron conjuntamente con los datos sedimentológicos disponibles, lo que permitió establecer que la variabilidad de 151 D. Rey et al. Propiedades magnéticas de los sedimentos de tipo estuarino... la susceptibilidad dependía de tres factores principales: (a) procedencia y origen de los sedimentos, (b) régimen hidrodinámico de la zona y (c) presencia de partículas contaminantes discretas de origen antropogénico. También puede concluirse que la evolución de las fases magnetomineralógicas durante la diagénesis temprana está controlada por el contenido en materia orgánica, lo que a su vez determina el potencial de oxidación-reducción.Meassurement of magnetic susceptibility has allowed the assesment of the marine influence and diagenetic evolution of coastal sediments from the Rías Baixas. This is based on geographically and vertically distributed data. The lowfield susceptibility () of over 200 samples of surficial seabed sediments of the Rias of Vigo and Pontevedra showed a significant increase towards the open sea and away from continental influenced areas. Vertical variability of the susceptibility was evaluated in 80 samples obtained from three 60 to 90 cm long gravity corers in the Ria de Pontevedra. These samples showed a very strong decrease in susceptibility with depth. The surficial susceptibility values correlated well with the textural characteristics of the sediments, suggesting a link between sediment provenance and origin of the magnetic signal. To further evaluate these relationships, the available sedimentological data were completed with a number of elemental and mineralogical analysis. In addition some basic magnetic parameters were obtained for selected specimens. The combined analysis of these data showed that the spatial variability of the susceptibility observed in the different granulometric fractions can be spatially related to: (a) sediment provenance and origin, (b) hydrodynamic regime established between the Rias and the adjacent shelf, (c) antropogenic solid particulate pollution. It can also be concluded that the evolution of the magnetomineralogical phases during the early stages of burial and diagenesis is controlled by the organic matter content which in turn controls the redox potential