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Wyszukujesz frazę "Aziz, A." wg kryterium: Autor


Tytuł:
Magnetic Properties of Zinc Doped Ferrites
Autorzy:
Abd El-Ati, M. I.
Kafafy, Aziz M.
Tawfik, A.
Powiązania:
https://bibliotekanauki.pl/articles/1887816.pdf
Data publikacji:
1991-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Gg
75.50.Dd
Opis:
A series of samples of the system Co$\text{}_{1-x}$Zn$\text{}_{x}$Fe$\text{}_{2}$O$\text{}_{4}$ (x = 0.0, 0.3, 0.4, 0.5 and 0.8) have been prepared by the usual ceramic technique. X-ray analysis shows that they are cubic spinel (single phase). The lattice parameter a and the bulk density D are measured for the samples. The substitution experiments replacing Co$\text{}^{2+}$ by Zn$\text{}^{2+}$ furnish new significant fact concerning the magnetic behaviour of ferrites. The magnetic strength of the magnetic ions on the Band A-sites can be varried relative to each other by the substitution of Zn$\text{}^{2+}$. The increase of density of the composition increases the magnetic interaction of the dipole moment at the B-sites.
Źródło:
Acta Physica Polonica A; 1991, 79, 6; 889-894
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrical and Dielectric Properties of Amorphous Ge$\text{}_{1}$Se$\text{}_{1.35}$TL$\text{}_{0.1}$ Films
Autorzy:
Abdel-Aziz, M. M.
Afifi, M. A.
Labib, H. H.
El-Metwally, E. G.
Powiązania:
https://bibliotekanauki.pl/articles/2014346.pdf
Data publikacji:
2000-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Ng
72.20.-i
Opis:
The temperature dependence of the DC and AC electrical conductivity were measured for Ge$\text{}_{1}$Se$\text{}_{1.35}$Tl$\text{}_{0.1}$ films. The value of DC electrical conduction energy ΔE$\text{}_{σ}$ does not depend on film thickness in the investigated range with mean value of 0.72eV. The AC conductivity σ$\text{}_{AC}$ is related to frequency by the expression σ$\text{}_{AC}$=Aω$\text{}^{S}$, where S is the frequency exponent which decreases linearly with increasing temperature. This can be explained in terms of the pair (bipolaron) correlated barrier hopping model suggested by Elliott. The frequency and temperature dependence of real and imaginary parts of the dielectric constant were studied for Ge$\text{}_{1}$Se$\text{}_{1.35}$Tl$\text{}_{0.1}$ films. The dielectric constant (real part) and the dielectric loss (imaginary part) increase with increasing temperature and decrease with increasing frequency in the investigated range of frequency and temperature. The maximum barrier height W$\text{}_{M}$ can be calculated according to the Giuntini equation at different temperatures. The obtained value of W$\text{}_{M}$ is in good agreement with the theory of hopping of charge carriers over a potential barrier as suggested by Elliott in case of chalcogenide glasses.
Źródło:
Acta Physica Polonica A; 2000, 98, 4; 393-399
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of smart sorting machine using artificial intelligence for chili fertigation industries
Autorzy:
Abdul Aziz, M. F.
Bukhari, W. M.
Sukhaimie, M. N.
Izzuddin, T.A.
Norasikin, M.A.
Rasid, A. F. A.
Bazilah, N. F.
Powiązania:
https://bibliotekanauki.pl/articles/2141810.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
precision agriculture
artificial neural network
smart fertigation
Opis:
This paper presents an automation process is a need in the agricultural industry specifically chili crops, that implemented image processing techniques and classification of chili crops usually based on their color, shape, and texture. The goal of this study was to develop a portable sorting machine that will be able to segregate chili based on their color by using Artificial Neural Network (ANN) and to analyze the performance by using the Plot Confusion method. A sample of ten green chili images and ten red chili images was trained by using Learning Algorithm in MATLAB program that included a feature extraction process and tested by comparing the performance with a larger dataset, which are 40 samples of chili images. The trained network from 20 samples produced an overall accuracy of 80 percent and above, while the trained network from 40 samples produced an overall accuracy of 85 percent. These results indicate the importance of further study as the design of the smart sorting machine was general enough to be used in the agricultural industry that requires a high volume of chili crops and with other differentiating features to be processed at the same time. Improvements can be made to the sorting system but will come at a higher price.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2021, 15, 4; 44-52
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Municipal solid waste generation, composition and management: Issues and challenges. A case study
Autorzy:
Ahsan, A.
Alamgir, M.
Imteaz, M.
Shams, S.
Rowshon, M. K.
Aziz, M. G.
Idrus, S.
Powiązania:
https://bibliotekanauki.pl/articles/208304.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
municipal solid waste
solid wastes
waste management
medical waste management
stałe odpady komunalne
odpady stałe
gospodarowanie odpadami
zagospodarowanie odpadów medycznych
Opis:
Khulna is the third largest metropolitan city in Bangladesh and a centre with intensive commercial and industrial activities. Rapid urbanization and increased migration of people from rural and coastal areas has put tremendous pressure on its existing solid waste management. The status of the existing municipal solid waste (MSW) management tiers such as generation, source storage, collection, on-site storage, transportation, and open dumping has been identified in this study. The daily generation of MSW is estimated as 520 Mg, of which food and vegetable wastes are the main components (79% on average). The major source of generated MSW is residential areas, which is 85.87% of total generation, whereas 11.60% in commercial areas, 1.02% in institutional areas, 0.55% in street sweeps and 0.96% in other areas. About 50% of total generated waste is disposed daily to the dumping site and the rest remains uncollected and unmanaged. Non-governmental organizations and community based organizations play an important role in primary collection, composting of organic wastes and medical waste management.
Źródło:
Environment Protection Engineering; 2015, 41, 3; 43-59
0324-8828
Pojawia się w:
Environment Protection Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Silica Bonding Reaction on Fly Ash Based Geopolymer Repair Material System with Incorporation of Various Concrete Substrates
Autorzy:
Al Bakri Abdullah, Mohd Mustafa
Aziz, Ikmal Hakem A.
Zailani, Warid Wazien Ahmad
Rahim, Shayfull Zamree Abd
Yong, Heah Cheng
Sandu, Andrei Victor
Peng, Loke Siu
Powiązania:
https://bibliotekanauki.pl/articles/2174557.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fly ash geopolymer
repair material
concrete substrate
interfacial zone transition
Opis:
This paper presents an experimental investigation on the mechanical properties and microstructure of geopolymer repair materials mixed using fly ash (FA) and concrete substrates. An optimal combination of FA and concrete substrate was determined using the compressive test of geopolymer mortar mixed with various concrete substrate classes. It was found that the contribution of (C35/45) concrete substrates with the FA geopolymer mortar increases the 28-day bonding strength by 25.74 MPa. The microstructure analysis of the samples using scanning electron microscopy showed the denser structure owing to the availability of high calcium and iron elements distribution. These metal cations (Ca2+ and Fe3+) are available at OPC concrete substrate as a result from the hydration process reacted with alumina-silica sources of FA and formed calcium aluminate silicate hydrate (C-A-S-H) gels and Fe-bonding linkages.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 4; 1277--1281
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Calcination Temperature on Structural and Optical properties of ZnO-SiO2 Nanocomposite by Simple Thermal Treatment Route
Autorzy:
Alibe, I. M.
Matori, K. A.
Aziz, S. H. A.
Yazid, Y.
Saion, E.
Alibe, A. M.
Zaid, M. H. M.
Ghapur Engku, E. A. A.
Zangina, T.
Powiązania:
https://bibliotekanauki.pl/articles/351868.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
optical properties
calcination
phosphor
nanocomposite
Opis:
This study offers a new method to synthesize facilely willemite (Zn2 SiO4 ) based phosphor at the temperature of 800°C. The ZnO-SiO2 nanocomposite was calcined at different temperatures between 500 and 1000°C. The structural, morphological and optical properties of the nanocomposite obtained at various calcination temperatures were studied using different techniques. The FT-IR, XRD and the UV-vis result confirmed the formation of willemite phase. The precursor was confirmed to be amorphous by XRD at room temperature, but upon calcination temperature at 500°C, it was transformed into a crystalline structure. The crystallinity and the particle size of the nanocomposite increase as the calcination temperature were increased as revealed by XRD and TEM measurement. The sample exhibits a spherical morphology from 500 to 800°C and dumbbell-like morphology above 800°C as shown by the FESEM images. The absorption spectrum suffers intense in lower temperature and tends to shift to lower wavelength in the UV region as the calcination temperature increases. The band gap values were found to be increasing from 3.228-5.550 eV obtained between 500 to 1000°C, and all the results confirm the formation of willemite phase at 800°C.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 2; 539-545
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Accuracy Analysis Comparison of Supervised Classification Methods for Mapping Land Cover Using Sentinel 2 Images in the Al‑Hawizeh Marsh Area, Southern Iraq
Autorzy:
Alwan, Imzahim A.
Aziz, Nadia A.
Powiązania:
https://bibliotekanauki.pl/articles/1838006.pdf
Data publikacji:
2021
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
land cover mapping
Sentinel 2
supervised classification
maximum likelihood
Support Vector Machine (SVM)
confusion matrix
Opis:
Land cover mapping of marshland areas from satellite images data is not a simple process, due to the similarity of the spectral characteristics of the land cover. This leads to challenges being encountered with some land covers classes, especially in wetlands classes. In this study, satellite images from the Sentinel 2B by ESA (European Space Agency) were used to classify the land cover of Al Hawizeh marsh/Iraq Iran border. Three classification methods were used aimed at comparing their accuracy, using multispectral satellite images with a spatial resolution of 10 m. The classification process was performed using three different algorithms, namely: Maximum Likelihood Classification (MLC), Artificial Neural Networks (ANN), and Support Vector Machine (SVM). The classification algorithms were carried out using ENVI 5.1 software to detect six land cover classes: deep water marsh, shallow water marsh, marsh vegetation (aquatic vegetation), urban area (built up area), agriculture area, and barren soil. The results showed that the MLC method applied to Sentinel 2B images provides a higher overall accuracy and the kappa coefficient compared to the ANN and SVM methods. Overall accuracy values for MLC, ANN, and SVM methods were 85.32%, 70.64%, and 77.01% respectively.
Źródło:
Geomatics and Environmental Engineering; 2021, 15, 1; 5-21
1898-1135
Pojawia się w:
Geomatics and Environmental Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Zeolite Phase Made from Rice Husk Ash and Sidrap Clay
Autorzy:
Armayani, M.
Mansur, Musdalifa
Asra, Reza
Irwan, Muh
Ramadhanty, Dhian
Subaer, Subaer
Abdullah, Mohd Mustafa Al Bakri
Aziz, Ikmal Hakem A.
Jeż, Bartłomiej
Nabiałek, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/2203746.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
autoclave
clay
rice husk ash
zeolite
Opis:
Zeolite has been successfully synthesized from clay and rice husk ash in the form of powder by using the hydrothermal method with variations in chemical compositions of alkaline solution and the amount of rice husk ash. The clay raw material was obtained from the Sidrap area of South Sulawesi and rice husk ash is obtained from the burning pile of rice husks. Sidrap clay and rice husk ash were activated using an alkaline solution of NaOH and varied rice husk ash and the addition of AlCl3. The addition of AlCl3, an alkaline solution of NaOH and H2O was used in the amount of 25.5 grams and variations of rice husk ash were 2.5 grams and 6.5 grams. Meanwhile, without the addition of AlCl3, an alkaline solution of NaOH and H2O was used for 20.5 grams and variations of rice husk ash from 2.5 grams and 6.5 grams. Then the mixture was then put into an autoclave with a temperature of 100°C for 3 hours. The basic material used in the manufacture of zeolite is carried out by X-ray Fluorescence (XRF) characterization to determine the constituent elements of basic material, which showed the content of SiO2 was 45.80 wt% in the clay and 93.40% in the rice husk ash. The crystalline structure of the zeolite formed was characterized by X-Ray Diffraction (XRD). It was found the resulting zeolite were identified as Zeolite-Y, Hydrosodalite, and ZSM-5. The microstructure properties of the resulting zeolite were determined by using Scanning Electron Microscopy (SEM).
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 269--274
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Naoh Molar Concentration on Microstructure and Compressive Strength of Dolomite/Fly Ash-Based Geopolymers
Autorzy:
Azimi, Emy Aizat
Salleh, Mohd M. A. A.
Abdullah, Mohd Mustafa Al Bakri
Aziz, Ikmal Hakem A.
Hussin, Kamarudin
Chaiprapa, Jitrin
Vizureanu, Petrica
Yoriya, Sorachon
Nabiałek, Marcin
Wyslocki, Jerzy J.
Powiązania:
https://bibliotekanauki.pl/articles/2125545.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
dolomite/fly ash
geopolymer
NaOH concentration
synchrotron
micro-XRF
Opis:
Dolomite can be used as a source of aluminosilicate to produce geopolymers; however, this approach is limited by its low reactivity. This study analyzes the viability of producing geopolymers using dolomite/fly-ash with sodium silicate and NaOH solutions (at multiple concentrations) by determining the resultant geopolymers’ compressive strengths. The dolomite/fly-ash-based geopolymers at a NaOH concentration of ~22 M resulted in an optimum compressive strength of 46.38 MPa after being cured for 28 days, and the SEM and FTIR analyses confirmed the denser surface of the geopolymer matrix. The synchrotron micro-XRF analyses confirmed that the Ca concentration exceeded that of Si and Mg, leading to the formation of calcium silicate hydrate, which strengthens the resulting geopolymers.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 3; 993--998
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Indication of urban expansion of Gujranwala city (Pakistan) by remote sensing and GIS
Autorzy:
Aziz, A.
Anwar, M.M.
Rani, M.
Ahmad, S.
Zaheer, S.
Powiązania:
https://bibliotekanauki.pl/articles/2049753.pdf
Data publikacji:
2019
Wydawca:
Fundacja na Rzecz Młodych Naukowców
Tematy:
remote sensing
industrial revolution
Earth surface system
human influence
ecological process
human activity
temporal variation
GIS
urban sprawl
ecology
time
Opis:
Land-cover by land-use shows the influence of human on earth surface by different phenomena’s, ecological processes and human activities, its indication is a parameter of measurement how and with which extent the human influenced the natural surface with temporal variations. The change detection technique is used based upon the temporal observations from 2000 to 2015. Study area is one of the most populated city of Pakistan where industrial revolution is at its peak. The whole study area is categorized into four classes (i.e. Agricultural, Barren, Built-up and semi natural surfaces). The observational intervals were divided into three main classes i.e. 2000 to 2005, 2005 to 2010 and 2010 to 2015. Remarkable changes were occurred in built up area from 2000 to 2015 which is 38.6 % of total area, while the total change/decreased in barren land is -332 9(ha), similarly the Parks and grasses are also in decreasing extent and affect the local biodiversity and natural environment. The land cover is directly proportional to population expansion of urban city. For making the prediction of future urban expansion, previously occurred changes were aggregated to come up with a single value and then adding it to the recent land-use values. The mapping and analysis was undertaken through techniques of remote sensing and GIS, which proved to be very effective to measure the changes, and trend of changes with time, this mapping not only tells us the scale of change but, also tells us the patterns and the forces which causes these changes.
Źródło:
Environment, Earth and Ecology; 2019, 3, 1; 13-23
2543-9774
2451-4225
Pojawia się w:
Environment, Earth and Ecology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Landscape change and human environment
Autorzy:
Aziz, A.
Anwar, M.M.
Powiązania:
https://bibliotekanauki.pl/articles/2049757.pdf
Data publikacji:
2019
Wydawca:
Fundacja na Rzecz Młodych Naukowców
Tematy:
landscape change
human environment
human activity
landscape management
Human ecology
human activities
environment
landscape
Landscape Changes
Opis:
Landscape and human are the constituents of the natural surroundings in which changing occurred temporally and spatially. The relationship between landscape and environment is not seen by a singular framework or a bare structure. A landscape has different functions and characteristics, when meet specific requirements, then set an ecology in giving context. Every landscape has its own scenario based upon the dimension of human and its kinship with them. Man are the ecosystem managers, the landscape features provide a road map and built human ecology. Development is occurring by landscape change, change of environment and the kinship between human and landscape, study of these phenomena provide us a theoretical framework to assess the man land relationship as is done in this case study. This paper aims to describe how, each individual in a particular environment is participating in change of the landscape. The influence of human is a magnitude of actions upon the landscape and this magnitude shape the local landscape. The paper discussed through a brightness on the dynamics of landscape change in the 21st century due to globalization and modern dimensions and presents us a complex web of human with non-human relationship of ecology, economy and history, which alter the landscape. This paper concluded a reflection of cultural values on physical environment and landscape change to build environment and human ecology.
Źródło:
Environment, Earth and Ecology; 2019, 3, 1; 7-12
2543-9774
2451-4225
Pojawia się w:
Environment, Earth and Ecology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electroluminescence Enhancement of Polymer Light Emitting Diodes Through Surface Plasmons by Ag Nanoplates
Autorzy:
Aziz, T.
Salleh, M.
Bakar, N.
Umar, A.
Rahman, M.
Powiązania:
https://bibliotekanauki.pl/articles/1186484.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Mf
Opis:
This paper reports a study on the surface plasmon effect of Ag nanoplates on electroluminescent property of polymer light emitting diodes. The diode is a single layer light emitting device made of poly [9,9-di-(2-ethylhexyl)-fluorenyl-2,7-diyl] (PEHF). 5 wt.% of Ag nanoplates were incorporated into the PEHF layer. The results showed that the electroluminescence intensity of the diodes is increased by 51.85%, compared with the device without the Ag nanoplates. The enhancement is due to the coupling process between the Ag surface plasmon with the emission light from the PEHF. The occurrence of the coupling process was proved firstly based on the fact that the exciton lifetime of the PEHF:Ag layer is shorter than that without Ag, as measured by time-resolved photoluminescence spectroscopy. Secondly, the PEHF photoluminescence peak at 425 nm is overlaping with the surface plasmon absorption peak of Ag nanoplates.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 711-713
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Green chemistry for the preparation of silver nanoparticles using mint leaf leaves extracts and evaluation of their antimicrobial potential
Autorzy:
Aziz, Wisam J.
Jassim, Haneen A.
Powiązania:
https://bibliotekanauki.pl/articles/1112556.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Green synthesis
Mentha (Mint)
Silver Nanoparticles
Opis:
The aim of this study was to develop a green synthesis of silver nanoparticles using mint plant leaves extracts. The fresh suspension of plant extracts was yellowish-green in color. However, after the addition of AgNO3 within 15min, the suspension showed a change in color to dark brown after 5 hours of incubation at room temperature. The formation of silver nanoparticles was confirmed using UV-Vis spectral analysis and revealed silver surface plasmon resonance band to be in a range around 200-500 nm. The XRD pattern showed the characteristic bragg peaks of (111), (200) and (220) planes of the face center cubic (FCC) silver nanoparticles AgNPS. Under scanning electron microscope (SEM), silver nanoparticles with a mean particle size of 26 nm and a spherical shape were most frequently observed. In testing, the synthesized AgNPs colloidal solution showed better antibacterial activity against both Gram-positive and Gram-negative bacterial strains. The diameter of the inhibition zones of AgNPs at 50 µg/ml concentration against bacterial strains such as Bacillus subtilis and Escherichia coli were 25 mm and 20 mm, respectively.
Źródło:
World News of Natural Sciences; 2018, 18, 2; 163-170
2543-5426
Pojawia się w:
World News of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Delphi technique for generating criteria and indicators in monitoring ecotourism sustainability in Northern forests of Iran: Case study on Dohezar and Sehezar Watersheds
Autorzy:
Barzekar, G.
Aziz, A.
Mariapan, M.
Ismail, M.H.
Hosseni, S.M.
Powiązania:
https://bibliotekanauki.pl/articles/38399.pdf
Data publikacji:
2011
Wydawca:
Instytut Badawczy Leśnictwa
Tematy:
Delphi method
ecological indicator
monitoring
ecotourism
sustainability
forest
Iran
watershed
Opis:
Ecotourism is widely accepted as the most effective type of sustainable development. For monitoring ecotourism sustainability in the Northern forest of Iran, a study was designed to help identifying criteria and indicators (C&I) with the principle goal to ensure the objectives of forest management, and at the same time – maintain processes in a sustainable manner. Indicators act as an instrument which can be used for monitoring sustainability. Hence indicators should be multidisciplinary, and cover all aspect of social, ecological, cultural, economic and institutional factors affecting sustainability of ecotourism. In this study, C&I were identified by using the Delphi approach through multidisciplinary panel team. Three rounds of meetings were held for discussions and dissemination of research to a panel of local experts. At the end of the second round we reached a consensus on 9 criteria and 61 indicators, which include 21 indicators related to ecological aspects, 8 to economic aspects, 21 to social aspects, 6 to cultural aspects and 5 to institutional aspects. The selected indicators would be applied by the Iranian Cultural, Heritage, Handicrafts and Tourism Organization for monitoring ecotourism sustainability in the Northern forest of Iran.
Źródło:
Folia Forestalia Polonica. Series A . Forestry; 2011, 53, 2
0071-6677
Pojawia się w:
Folia Forestalia Polonica. Series A . Forestry
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Eutrophication problems in the Western Harbour of Alexandria, Egypt
Autorzy:
Dorgham, M.M.
Abdel-Aziz, N.E.
El-Deeb, K.Z.
Okbah, M.A.
Powiązania:
https://bibliotekanauki.pl/articles/49044.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
biomass
nutrient
water quality
Alexandria Western Harbour
plankton
salinity
Egypt
eutrophication
Opis:
Eutrophication-related problems in the Western Harbour ofA lexandria were studied monthly from April 1999 to March 2000. Variation in salinity appeared to be the key to all changes in water quality and plankton abundance in the harbour. Both at the surface and near the bottom the salinity was lower (annual average: 35.1 and 38.3 PSU respectively) than in the open sea (39 PSU). Dissolved oxygen levels indicated poor aeration conditions along the water column (2.3–3.98 mg l−1). Average pH values were approximately similar in the two layers (8.1 and 8 respectively) but exhibited different ranges ofv ariations. Nutrient salts varied widely, often occurring in high concentrations, with ranges of 0.12–5.7 and 0.06–2.6 μM at the surface and the bottom respectively for phosphate, 0.21–20.46 and 0.25–18.12 μM for nitrate, 0.29–3.3 and 0.23–1.66 μM f or nitrite, 0.56–57.46 and 2.32–43.73 μM for ammonia and 0.3–36.3 and 0.48–38.4 μM for silicate. As a result ofn utrient enrichment, phytoplankton growth was very intensive, reflected by an abnormally high concentration ofc hlorophyll a (annual average: 33.82 μg l−1). At the same time the death ofl arge numbers ofp hytoplankton cells could be inferred from the relatively large amount of phaeopigment (annual average: 10.39 μg l−1). The high levels ofn utrient salts and phytoplankton biomass together serve as a good indicator ofhig h eutrophication levels in the Western Harbour throughout the year. These conditions clearly affected the zooplankton stock, which varied between 5.8–93.6×103 indiv. m−3, although for most of the time values remained at a low level (annual average: 26 728 indiv. m−3).
Źródło:
Oceanologia; 2004, 46, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł

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