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Wyświetlanie 1-15 z 1888
Tytuł:
Kryzysy w procesie integracji europejskiej i sposoby ich przezwyciężania –wprowadzenie do problematyki badań.
Autorzy:
A, Wojtaszczyk, Konstanty
Jadwiga, Nadolska,
F, Czub, Jarosław
Powiązania:
https://bibliotekanauki.pl/articles/894826.pdf
Data publikacji:
2020-03-30
Wydawca:
Uniwersytet Warszawski. Wydawnictwa Uniwersytetu Warszawskiego
Tematy:
kryzys
aksjologia
legitymizacja
model demokracji
gospodarka
modernizacja
komunikacja
Polska
Unia Europejska
Opis:
The article presents the assumptions of the interdisciplinary research project, whose object of analysis are crises in the European integration process. The project distinguishes 12 planes of analysis of the crises, revealing their different aspects (crises in the integration process from a theoretical perspective, crises in the process of European integration from a historical perspective, axiological crisis, crisis of legitimacy, crisis of the model of democracy in Europe, crisis of the modernisation of the EU, financial and economic crisis, social crisis, structural crisis, crisis of communication, Poland and the crises in the EU, EU in the international arena during crisis). The article discusses the objectives and research hypothesis, significance of the project and the expected results of the project. For each module of the project, theories explaining the origin, nature, consequences and ways of overcoming the crisis phenomena were distinguished and the research methods by which research goals are planned to be achieved were specified. Artykuł przedstawia założenia interdyscyplinarnego projektu badawczego, którego przedmiot analizy stanowią kryzysy w procesie integracji europejskiej. W projekcie wyodrębniono 12 płaszczyzn analizy zjawisk kryzysowych ujawniających się w procesie integracji (kryzysy w procesie integracji z perspektywy teorii, kryzysy w procesie integracji europejskiej z perspektywy historycznej, kryzys aksjologiczny, kryzys legitymizacji, kryzys modelu demokracji w UE, kryzys modernizacyjny, kryzys finansowo-ekonomiczny, kryzys społeczny, kryzys strukturalny, kryzys komunikacji, Polska wobec kryzysów w UE, UE w poszukiwaniu miejsca na arenie międzynarodowej). Omówione zostały cele i hipoteza badań, znaczenie projektu oraz spodziewane efekty realizacji projektu. Przy każdym module projektu wskazano na teorie wyjaśniające genezę, naturę, następstwa i sposoby przezwyciężania zjawisk kryzysowych oraz metody badawcze, wykorzystywane do osiągnięcia zamierzonych celów.
Źródło:
Przegląd Europejski; 2014, 3 (33); 8-23
1641-2478
Pojawia się w:
Przegląd Europejski
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of penetration rate of rotary-percussive drilling using artificial neural networks – a case study
Prognozowanie postępu wiercenia przy użyciu wiertła udarowo-obrotowego przy wykorzystaniu sztucznych sieci neuronowych – studium przypadku
Autorzy:
Aalizad, S. A.
Rashidinejad, F.
Powiązania:
https://bibliotekanauki.pl/articles/219500.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
prędkość wiercenia
wiertło obrotowo-udarowe
sztuczne sieci neuronowe
urządzenia udarowe
kopalnia rud żelaza Sangan
penetration rate
rotary-percussive drilling
artificial neural networks
top hammer drilling
Sangan iron mine
Opis:
Penetration rate in rocks is one of the most important parameters of determination of drilling economics. Total drilling costs can be determined by predicting the penetration rate and utilized for mine planning. The factors which affect penetration rate are exceedingly numerous and certainly are not completely understood. For the prediction of penetration rate in rotary-percussive drilling, four types of rocks in Sangan mine have been chosen. Sangan is situated in Khorasan-Razavi province in Northeastern Iran. The selected parameters affect penetration rate is divided in three categories: rock properties, drilling condition and drilling pattern. The rock properties are: density, rock quality designation (RQD), uni-axial compressive strength, Brazilian tensile strength, porosity, Mohs hardness, Young modulus, P-wave velocity. Drilling condition parameters are: percussion, rotation, feed (thrust load) and flushing pressure; and parameters for drilling pattern are: blasthole diameter and length. Rock properties were determined in the laboratory, and drilling condition and drilling pattern were determined in the field. For create a correlation between penetration rate and rock properties, drilling condition and drilling pattern, artificial neural networks (ANN) were used. For this purpose, 102 blastholes were observed and drilling condition, drilling pattern and time of drilling in each blasthole were recorded. To obtain a correlation between this data and prediction of penetration rate, MATLAB software was used. To train the pattern of ANN, 77 data has been used and 25 of them found for testing the pattern. Performance of ANN models was assessed through the root mean square error (RMSE) and correlation coefficient (R2). For optimized model (14-14-10-1) RMSE and R2 is 0.1865 and 86%, respectively, and its sensitivity analysis showed that there is a strong correlation between penetration rate and RQD, rotation and blasthole diameter. High correlation coefficient and low root mean square error of these models showed that the ANN is a suitable tool for penetration rate prediction.
Postęp wiercenia przy wierceniach skał jest jednym z podstawowych parametrów decydujących o opłacalności przedsięwzięcia. Całkowite koszty prowadzenia prac wiertniczych określa się w oparciu o prognozowane tempo postępu wiercenia, parametr ten uwzględnia się następnie przy planowaniu prac wydobywczych. Niektóre spośród licznych czynników wpływających na postęp wiercenia przy użyciu wiertła obrotowo-udarowego nie zostały jeszcze w pełni rozpoznane. Przy prognozowaniu postępu wiercenia prowadzonego przy użyciu urządzeń udarowo-obrotowych uwzględniono cztery rodzaje skał obecnych w kopalni Sangan, leżącej w prowincji Khorasan-Razavi w północno -wschodniej części Iranu. Wybrane czynniki mające wpływ na postęp prac wiertniczych pogrupowano w trzy kategorie: właściwości skał, warunki prowadzenia prac wiertniczych oraz plan prowadzenia wiercenia. Parametry określające właściwości skał to gęstość, jakość skał (RQD) i wytrzymałość na ściskanie jednoosiowe, wytrzymałość skał otrzymywana w oparciu o test brazylijski, porowatość, twardość Mohra, moduł Younga, prędkość propagacji fali, Parametry określające warunki prowadzenia wierceń obejmują: udar, prędkość obrotowa, siła naporu, ciśnienie płukania, zaś parametry związane z planem prowadzenia wiercenia obejmują: wymiary otworu wiertniczego i długość. Właściwości skał określono laboratoryjnie, warunki i plan wierceń badano w terenie. Korelacji pomiędzy prędkością postępu wiercenia i właściwościami skał oraz warunkami i planem prac wiertniczych poszukiwano przy użyciu sztucznych sieci neuronowych (ANN). Zbadano 102 otwory wiertnicze, przeanalizowano warunki prowadzenia wierceń, plany prac i zarejestrowano czasy ich prowadzenia. W celu znalezienia korelacji pomiędzy tymi danymi a prognozowaną prędkością wiercenia wykorzystano oprogramowanie MATLAB. W treningu sieci neuronowej wykorzystano 77 danych, 25 z nich otrzymano w drodze testowania wzorca. Wyniki działania sieci neuronowych oceniono w oparciu o błąd średniokwadratowy (RMSE) oraz współczynnik korelacji (R2). Dla zoptymalizowanego modelu (14-14-10-1) błąd średniokwadratowy i współczynnik korelacji wynoszą odpowiednio 0.1865 i 86%. Analiza wrażliwości wykazała istnienie silnej korelacji pomiędzy prędkością wiercenia a jakością skały, prędkością obrotową wiertła i średnicą otworu wiertniczego. Wysoki współczynnik korelacji i niska wartość błędu średniokwadratowego otrzymana dla tych modeli wskazuje, że metody wykorzystujące sztuczne sieci neuronowe są odpowiednie do prognozowania prędkości wiercenia.
Źródło:
Archives of Mining Sciences; 2012, 57, 3; 715-728
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The antioxidant and antibacterial activities of the essential oils of Marrubium vulgare growing wild in Eastern Algeria
Autorzy:
Abadi, A.
Abdellatif, F.
Powiązania:
https://bibliotekanauki.pl/articles/412468.pdf
Data publikacji:
2013
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Marrubium vulgare
Essential oil composition
GC-MS
antibacterial activities
antioxidant
Opis:
The chemical composition was analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). The constituents were identified by their mass spectra and Kovats’ indices. Fivety (50) components in the oil of M. vulgare were identified. The results demonstrated that the major components of the essential oil were : 4,8,12,16-Tetramethyl heptadecan-4-olid (16.97 %), Germacrene D-4-ol (9.61 %), α- pinéne (9.37 %), Phytol (4.87 %), Dehydro-sabina ketone (4.12 %), Piperitone (3.27 %), δ-Cadinene (3.13 %), 1-Octen-3-ol (2.35 %) and Benzaldehyde (2.31 %). The antioxidant activity of the oils was assessed by measurement of metal chelating activity, the reductive potential, the free radical scavenging (DPPH) assay. The antioxidant activity was compared with that of synthetic antioxidants: butylated hydroxyanisole (BHT) , and the essential oils . The results showed as the Essential oil of M vulgare was evaluated for its antibacterial activities against Gram-positive and Gram negative pathogenic bacteria: Listeria monocytogene, Pseudomonas aeruginosa , Agrobacterium tumefaciens and Salmonella enterica.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2013, 10, 2; 159-166
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of annealing and anisotropic behaviour on tensile and fatigue properties of AA 8090
Autorzy:
Abass, M. H.
Mahmud, F.
Alali, M. S.
Abood, A. N.
Powiązania:
https://bibliotekanauki.pl/articles/378497.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
AA 8090
anisotropic behavior
annealing
tensile strength
fatigue strength
AA8090
zachowanie anizotropowe
wyżarzanie
wytrzymałość na rozciąganie
wytrzymałość zmęczeniowa
Opis:
Purpose: This paper aims to assess microstructures and mechanical properties of annealed and un-annealed Al-Li alloys (AA8090) and provide valid information regarding influence of anisotropy on tensile properties, fatigue lives. Design/methodology/approach: The methodology included investigating the influence of annealing on grain size, tensile strength and fatigue lives of AA8090. Optical microscope, scanning electron microscope and X-ray diffraction were utilized to analyse the crystallographic texture. Findings: The results showed that the un-annealed alloy exhibited much finer grain structure in three directions, namely longitudinal (L) rolling direction, L-45° and Long transverse (LT) combined with stronger crystallographic texture. Regarding to mechanical properties, un-annealed alloy presented superior tensile strength with strong anisotropic behaviour. L and LT grains direction showed highest tensile strength value of 550 MPa and L-45° showed lowest tensile strength value of 420 MPa. Results of fatigue test revealed that annealed Al-Li alloy has lower fatigue lives with high influence of test direction on fatigue properties. Higher variation in fatigue life to failure links with un-annealed alloy over annealed alloy. Examination of fractured surface showed that the morphology of fractured surface is a mixture of ductile and brittle fractures in both annealed and un-annealed alloys with more brittle behaviour in un-annealed alloy. Research limitations/implications: The main challenge of this work is the determination of the test direction (test angle in respect to rolling direction), which is necessary to provide correct information regarding mechanical properties. Further study of low cycle fatigue can be done in future, which will be an excellent indication to mechanical properties of this alloy since it provides more understanding to the behaviour of the material and better comprehend crack propagation and strain stress concentration. Practical implications: AA8090 alloy is an important candidate for aerospace and aircraft industries. Influence of annealing heat treatment and rolling direction on mechanical properties of AA8090 alloy provides more accurate information to the manufacturers who deal with this alloy. Originality/value: This study is affording a significant information regarding the effect of annealing and anisotropic behaviour on mechanical properties of AA8090. To our knowledge, there are few reports that study this combination of factors on AA8090 alloy.
Źródło:
Archives of Materials Science and Engineering; 2019, 99, 1/2; 5-12
1897-2764
Pojawia się w:
Archives of Materials Science and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heavy Metal Concentrations along the Banks of the Sitnica River and in Four Types of Herbaceous Plants
Autorzy:
Abazi, A. S.
Sallaku, F.
Bytyçi, P.
Spahiu, M. H.
Millaku, F.
Powiązania:
https://bibliotekanauki.pl/articles/123595.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
concentration
metals
plant species
soils
Sitnica River
Opis:
This paper presents the results of the heavy metals accumulation (Cd, Cr, Pb, Cu, Zn, Mn, and Fe) in soils and plants (Typha angustifolia L., Urtica dioica L., Ranunculus sardous Crantz and Rumex Crispus L.) collected along the banks of the Sitnica River, which flows through various cities of Kosovo and is quite stressed due to the discharges of urban, industrial, and agricultural pollutants. The aim of this research was to verify the accumulation of heavy metals in water, soil and plants, since vegetables that used as food are cultivated in the vicinity of sample collection. The analyses were conducted with applied methodology in the analytic laboratory of Kosovo Agriculture Institute by using MP-AES 4200 for Cd and Cr, ASS-Scientific for Zn, Cu, Fe, Mn and Pb in plant samples, whereas 4100 MP-AES was used for determination of metals in soil. The results show variations in different metal values found in the samples of the analyzed soils and plants. The lowest values accumulation of the metals analyzed were recorded at A1 (Devetak Station) near the river source and did not contain anthropogenic influences, whereas the highest values were recorded at A3 (Kuzmin Station), which belongs to the middle flow of the Sitnica River that is polluted by wastewater (urban) discharges.
Źródło:
Journal of Ecological Engineering; 2018, 19, 5; 1-9
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of inclined magnetic field and Joule heating in mixed convective peristaltic transport of non-Newtonian fluids
Autorzy:
Abbasi, F. M.
Hayat, T.
Alsaedi, A.
Powiązania:
https://bibliotekanauki.pl/articles/200788.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
mixed convection
eyring-prandtl fluid
sutterby fluid
inclined magnetic field
konwekcja mieszana
płyn eyringa-prandtla
płyn sutterby
pole magnetyczne
Opis:
This article describes the influence of an inclined magnetic field on the mixed convective peristaltic transport of fluid in an inclined channel. Two types of non-Newtonian fluids are considered. The problem formulation is presented for the Eyring-Prandtl and Sutterby fluids. Viscous dissipation and Joule heating in the heat transfer process are retained. The presence of a heat source in the energy equation is ensured. The resulting problems are solved by the perturbation method. The plots for different parameters of interest are given and discussed. Numerical values of a heat transfer rate are given and analyzed.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2015, 63, 2; 501-514
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamical Electro-Optical Characterization of Policryps Gratings
Autorzy:
Abbate, G.
Marino, A.
Vita, F.
Powiązania:
https://bibliotekanauki.pl/articles/2035667.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Df
42.79.Kr
Opis:
We have studied the dynamical response at 633 and 1550 nm of a new polymer-liquid crystal composite, realized in a form of a thick grating. This composite is known as Policryps, an acronym that stands for "Polymer Liquid Crystals Polymer Slides", because it shows a sequence of polymeric sheets alternated by layers containing only liquid crystal. Policryps gratings can be electrically switched between diffracting and non-diffracting states with a good diffraction efficiency in the visible region. After optimization of their performances, including response time, in the near infrared region, they can be conveniently proposed as a key component in photonic devices for telecom applications. Our results show very interesting response times ranging from 1 to 3 ms (switching on) and from 0.1 to 0.4 ms (switching off). Furthermore, switching ON times appear to be ruled by two different physical mechanisms with characteristic times differing by one order of magnitude. A deeper insight of these mechanisms might lead to response times, all in the submillisecond range.
Źródło:
Acta Physica Polonica A; 2003, 103, 2-3; 177-186
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metal-titanium oxide / quantum dot porous silicon / silicon-metal solar cell
Autorzy:
Abd, Ahmad Naji
Mishjil, Khudheir A.
Abdulsada, Ali Hamid
Habubi, N. F.
Powiązania:
https://bibliotekanauki.pl/articles/1177996.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
AFM
FTIR
TiO2
X-Ray diffraction
XRD
electrochemical etching p-type silicon wafer
nanocrystalline porous silicon
Opis:
In this paper, the nanocrystalline porous silicon (PSi) films are prepared by electrochemical etching of p-type silicon wafer with current density 7 mA/cm2 and etching times on the formation nano-sized pore array with a dimension of around different etching time. The films were characterized by the measurement of XRD, FTIR spectroscopy and atomic force microscopy properties (AFM). We have estimated crystallites size from X-Ray diffraction about nanoscale for porous silicon and Atomic Force microscopy confirms the nanometric size Chemical fictionalization during the electrochemical etching show on the surface chemical composition of PS. The etching possesses inhomogeneous microstructures that contain a-Si clusters (Si3–Si–H) dispersed in amorphous silica matrix. From the FTIR analyses showed that the Si dangling bonds of the as-prepared PS layer have large amount of Hydrogen to form weak Si–H bonds. The atomic force microscopy investigation shows the rough silicon surface, with increasing etching process (current density and etching time) porous structure nucleates which leads to an increase in the depth and width (diameter) of surface pits. Consequently, the surface roughness also increase.
Źródło:
World Scientific News; 2018, 96; 134-148
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Seed Quality and Protein Classification of Some Quinoa Varieties
Autorzy:
Abd El-Hakim, Ahmed F.
Mady, Emad
Abou Tahoun, Ayman M.
Ghaly, Mohammed S. A.
Eissa, Mohamed A.
Powiązania:
https://bibliotekanauki.pl/articles/2025743.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
quinoa
seed vigour
seed quality
amino acids composition
agro-climatic zone
Opis:
Quinoa plants, originating from the Andean mountains in South America, have a large scale of biological diversity. Along with the cultivation favorableness of quinoa, it reveals superior nutrition aspects. In comparison with cereal crops, like rice, maize, and wheat, quinoa seeds contain valuable quantities of protein of remarkable quality. The current study compared four quinoa cultivars from different origins in terms of protein composition and germinability. In addition, this study focused on the effect of different geographical cultivation areas on the protein composition of wild Egyptian quinoa seeds and three other cultivars that vary in their cultivation origins. Significant differences were observed among the quinoa varieties in the germination percentage (GP), shoot length (SL), and root length (RL). Using the technology of Near-InfraRed Spectroscopy, the highest protein value was recorded for the American variety (18.39%), followed by the Wild Egyptian variety (17.16%). The aromatic phenylalanine recorded the highest concentration of the essential amino acid bulk. The Rainbow variety contained 12.7 g-aa/kg protein, followed by the wild Egyptian variety with 4.9 g-aa/kg protein. In turn, glutamic was the most abundant amino acid of the non-essential amino acids, with 10.1, 4, 23.4, and 4 (g-aa/kg protein) for quinoa varieties, Wild Egyptian, American, Rainbow, Black, respectively. SDS-PAGE was used to identify the allelic variations in the seed storage protein profiles among the studied quinoa varieties. The studied quinoa varieties showed 23.81% of the polymorphism in the protein bands, with the mean band frequency of 0.881. The resulting protein bands fluctuated in the range between 115.02 and 16 kDa. With a similarity percentage (90%), Wild Egyptian and the Rainbow quinoa varieties can be classified in one clade.
Źródło:
Journal of Ecological Engineering; 2022, 23, 1; 24-33
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Management of potato virus Y (PVY–NTN) causing potato tuber necrotic ringspot disease (PTNRD) in potato by prior treatment with a mild PVY strain
Autorzy:
Abdalla, O.A.
Eraky, A.I.
Mohamed, S.A.
Fahmy, F.G.
Powiązania:
https://bibliotekanauki.pl/articles/65943.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Egypt
pest management
potato virus Y
potato tuber
necrotic ringspot disease
potato
plant protection
mild strain
treatment
Opis:
Potato virus Y (PVY) is one of the most destructive viruses infecting potato in Egypt and worldwide. Recent research has shown that a necrotic PVY-NTN strain is infecting potato in Upper Egypt. Chemical control is not effective to control this viral pathogen. An alternative to control PVY infecting potato is using a mild PVY strain to elicit systemic cross protection in potato plants against infection with a severe necrotic strain of PVY. Results of this study showed that a PVY necrotic strain produced a significant lesser number of local lesions on diagnostic plants (Robinia pseudoacacia L.) when these plants were treated first with a mild PVY strain. Data obtained from greenhouse and field experiments indicated that treatment of potato plants (variety Burna) with a mild PVY strain significantly protected potato from infection with a severe necrotic PVY strain, and resulted in a significant increase in tuber yield compared with infected plants without prior treatment with a mild PVY strain. The highest increase in potato tuber yield was obtained when potato plants were inoculated with a mild PVY strain 3 days before challenging with the severe necrotic PVY strain. This study proved that using a mild strain of PVY can significantly protect potato plants from infection with a severe strain of this virus under both greenhouse and field conditions and can present a potential method to reduce losses due to infection of this virus in Assiut governorate and Upper Egypt.
Źródło:
Journal of Plant Protection Research; 2018, 58, 2
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydrometallurgical treatment of non-sulfide zinc ore for precipitation of zinc oxide nanoparticles
Autorzy:
Abdel-Aal, E.-S. A.
Rashad, M. M.
El-Shazly, A. N.
Ibrahim, I. A.
El-Shahat, M. F.
Powiązania:
https://bibliotekanauki.pl/articles/110748.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
zinc ore
sulfuric acid leaching
filtration rate
zinc sulfate
zinc oxide nanoparticles
MB photocatalytic degradation
Opis:
Acid leaching of Egyptian zinc ore from the Um Gheig area was carried out with sulfuric acid. This study determines the optimum conditions for dissolution of non-sulfide zinc ore. The optimum conditions are 25% -74m particle size, 45 °C temperature, 2 h leaching time, 1.1 stoichiometric molar ratio of H2SO4 to Zn, 1:3 solid/liquid ratio. The maximum filtration rate is 1.6 Mg Zn•m-2•day-1at pressure difference of 0.80 bar. The zinc recovery is about 90%. As the zinc ore contains zinc silicate, some additives were tested to enhance filtration and prevent formation of silica gel. To increase the added value of the product, zinc oxide was precipitated by a co-precipitation method in a nanosize powder with average particle size ~ 20 nm. Photocatalytic degradation of methylene blue dye under UV light using ZnO nanopowders produced at different conditions was investigated. Photocatalytic efficiency with methylene blue (MB) concentration was reduced as much as 85% in 240 min with the produced nanoparticles.
Źródło:
Physicochemical Problems of Mineral Processing; 2016, 52, 2; 729-737
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Different Copper Salts on the Mechanical and Ballistic Characteristics of Double Base Rocket Propellants
Autorzy:
Abdel-Ghani, N.
Elbeih, A.
Helal, F.
Powiązania:
https://bibliotekanauki.pl/articles/357974.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
double base rocket propellant
burning rate modifiers
ballistic performance
mechanical properties
Opis:
This paper discusses the enhancement in the ballistic performance of double base rocket propellants (DBRPs) by the addition of different copper salts vs lead salts as burning rate modifiers through stable combustion and the formation of a plateau region in the low pressure region. Compositions based on DBRPs containing different percentages of lead stearate and different types of copper salts were prepared and studied. For comparison, a conventional DBRP was studied. The ignition temperature and heat of combustion were determined experimentally, and the mechanical properties were measured and evaluated. The performance in terms of ballistic characteristics (burning rate, operating pressure) were measured at different throat diameters (8, 8.5, 9, 9.5 mm) and at different temperatures (−20 and 50 °C). Specific impulses were calculated using the ICT thermodynamic code. The experimental data from the proportional study indicate that the compositions containing the studied burning rate modifiers are superior to the original DBRP in respect of ballistic performance and mechanical properties.
Źródło:
Central European Journal of Energetic Materials; 2016, 13, 2; 469-482
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exploitation of industrial solid wastes for preparing zeolite as a value-added product and its kinetics as adsorbent for heavy metal ions
Autorzy:
Abdel-Hameed, Reham Mohamed
Abdel-Aal, Elsayed A.
Farghaly, Fatma E.
Ibrahim, Ibrahim A.
Abdel Khalek, Mohamed A.
Ahmed, Mohamed A.
Abdel-Messih, Micheal F.
Powiązania:
https://bibliotekanauki.pl/articles/1448799.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
zeolite P
aluminium wastes
hydrothermal process
metal ion removal
aluminum waste
Opis:
Aluminum and fumed silica as solid industrial wastes were converted to zeolite NaPas a value-addedproduct without any template. The hydrothermal process was optimized using static autoclave. The crystallization was carried out at 100, 120 and 150°C for 24, 48 and 72 h. The prepared zeolite of Si:Al ratio of 1.2 was characterized using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) provided with Energy Dispersive Spectroscopy (EDS), Surface Area, Fourier Transmitted Infra-Red (FTIR) and Thermal Analysis (TG-DSC). The crystalline phase was formed at 100°Cafter 72 hours and at 120°C after 48 hours, while it was formed after 24 honlyat 150°C. Increasing temperature and time lead to the conversion of the prismatic gibbsite crystals into plate-like structure of zeolitewhich is then formedcauliflower-like structure.The prepared zeolite was employed as adsorbent for $Ni^{2+}$ and $Cu2+ions from aqueous solution.The kinetic studies of adsorption processes were performed.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 1; 87-99
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 1888

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