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Wyświetlanie 1-15 z 15
Tytuł:
Etiology and pathology of epidemic outbreaks of avian influenza H5N1 infection in Egyptian chicken farms
Autorzy:
Ali, A.
Elmowalid, G.
Abdel-Glili, M.
Sharafeldin, T.
Abdallah, F.
Mansour, F.
Nagy, A.
Ahmed, B.
Abdelmoneim, M.
Powiązania:
https://bibliotekanauki.pl/articles/30849.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
Epidemic outbreaks of avian influenza (AI) virus H5N1 have been frequently reported in Egypt during the last nine years. Here we investigate the involvement of AI H5N1 in outbreaks of acute respiratory disease that occurred in several commercial chicken farms in Egypt in 2011, and we describe to the pathology caused by the virus in the course of the outbreak. Twenty-one chicken farms with history of acute respiratory symptoms and high mortalities were screened for AI H5N1. Virus identification was based on hemagglutination inhibition test, and PCR detection and sequencing of the hemagglutinin and neuraminidase genes. Virus distribution was determined by immunohistochemical staining of AI antigens in organs of infected birds. Standard H&E staining was performed for histological examination of affected organs. Eighty-one % of the examined birds, representing 100% of the screened farms, were positive for AI H5N1 virus. Phylogenetic analysis of the hemagglutinin and neuraminidase genes of the isolated virus reveals its affiliation to clade 2.2.1. Viral antigens were localized in the endothelial cells of the heart, liver, lungs and skin, where pathological lesions including congestion, hemorrhages, multifocal inflammation and necrosis were concurrently observed. According to the pattern of the viral antigen and lesion distribution in the visceral organs, we suggest cardiovascular and circulatory failures as the probable cause of death during these outbreaks. In conclusion, the present study further confirms the epidemic status of AI H5N1 virus in Egypt and reveals the highly pathogenic nature of the local isolates.
Źródło:
Polish Journal of Veterinary Sciences; 2015, 18, 4
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Short Range Synthetic Aperture Imaging Radar with Rotating Antenna
Autorzy:
Ali, F.
Urban, A.
Vossiek, M.
Powiązania:
https://bibliotekanauki.pl/articles/226520.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
radar
synthetic aperture
scanning
imaging
Opis:
The design of a short range synthetic aperture imaging radar is introduced in this paper. A radar hologram is acquired using a small omnidirectional antenna that is mounted on a rotating platform. After each turn of the platform a high resolution 360° 2D image is reconstructed; a rotating window function optimizes the reconstructed image function to get the best image focus for detecting both weak and strong scatterers. The rotating window function depends on the target direction and is executed for each image point and each target direction. The size of the synthetic aperture – and thus the lateral resolution of the imaging system – is determined by the diameter of the circular antenna trajectory. In contrast to common radar scanner concepts that utilize highly directional and thus bulky antennas, the proposed scanner concept has the advantage of using a small, lightweight omni-directional antenna. The developed radar system is much more compact and the scanning mechanics are significantly simplified. Furthermore, an omni-directional antenna offers very straightforward options for powering the radar on the rotation platform. Measurement results obtained with a 24 GHz FMCW short range radar sensor illustrate the performance of the proposed SAR imaging method.
Źródło:
International Journal of Electronics and Telecommunications; 2011, 57, 1; 97-102
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phytoextraction of Cr by maize (Zea mays L.) : the role of plant growth promoting endophyte and citric acid under polluted soil
Autorzy:
Ali, J.
Mahmood, T.
Hayat, K.
Afridi, M. S.
Ali, F.
Chaudhary, H. J.
Powiązania:
https://bibliotekanauki.pl/articles/204568.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
maize
phytoextraction
chromium
citric acid
Burkholderia vietnamiensis
Opis:
High chromium (Cr) toxicity has turned into a serious environmental concern. Cr contaminated agronomic soils negatively affect the growth and yield of crops. Current research was conducted to enhance the phytoextraction potential of maize by using Burkholderia vietnamiensis and citric acid (CA). Plants were subjected to three concentrations of Cr (0.86, 350, and 500 ppm). A pot experiment was conducted under greenhouse conditions with completely randomized design (CRD). After 72 days of experiment, plants were harvested to analyze the morphological and biochemical attributes of soil, bacteria and plant. Results revealed that plant fresh, dry biomass, root, shoot length and chlorophyll contents significantly increased by 56%, 50%, 58%, 78% and 60%, respectively, at 500 ppm Cr concentration in combine treatment of B. vietnamiensis and CA. Maize plants treated with both B. vietnamiensis and CA significantly increased the bioaccumulation (BA) of Cr up to 50% and translocation factor (TF) by 31%. Furthermore, superoxide dismutase (SOD), proline and peroxidase dismutase (POD) activities in leaves were markedly increased by 30%, 42% and 15%, respectively, when treated with CA. Current study reveals that exogenous co-application of B. vietnamiensis + CA enhance plant growth by alleviating heavy metal stress and accelerate the phytoextraction of Cr. Taking into account the heavy metal tolerance and accumulation capacity, Zea mays is suitable for phytoremediation of contaminated soils in combination with B. vietnamiensis and CA.
Źródło:
Archives of Environmental Protection; 2018, 44, 2; 73-82
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Slow Rusting Resistance in Iranian Barley Cultivars to Puccinia Striiformis sp.Hordei
Autorzy:
Ali Safavi, S.
Ahari, A.B.
Afshari, F.
Arzanlou, M.
Powiązania:
https://bibliotekanauki.pl/articles/65042.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
Race-specific resistance of barley (Hordeum vulgare L.) to the yellow rust caused by Puccinia striiformis f. sp. hordei, has been reported to be short-lived. Slow rusting resistance has been reported to last for a long time. Twenty Iranian barley cultivars along with resistant and susceptible controls were tested during the 2009-2010 and the 2010-2011 cropping seasons, in field plots at the Ardabil Agricultural Research Station (Iran). The cultivars were tested to identify slow rusting genotypes through epidemiological variables which included: final rust severity (FRS), apparent infection rate (r), relative area under the disease progress curve (rAUDPC), and coefficient of infection (CI). Moreover, differential sets were evaluated in order to determine effective and ineffective resistance genes to barley yellow rust. Results of the mean comparison of resistance parameters showed that cultivars Makouee, Dasht, Fasih, and Arass had low values of FRS, CI, r and rAUDPC compared with susceptible cultivars. The cultivars Walfajre, Abidar and Sahand which had moderate values of the different parameters, were marked as possessing a moderate level of slow rusting. The rest of the cultivars which had high values of different quantitative parameters, were grouped as having a low level of slow rusting or as susceptible. The correlation coefficient between different parameters of slow rusting was significantly high (r = 0.83-0.98). The virulence profile of the prevalent races revealed that rpsEm1, rpsEm2, rpsHF, Rps4, rpsVa1, rpsVa2, rpsAst were effective, and rps2, Rps1.b were ineffective resistance genes during the two year testing period.
Źródło:
Journal of Plant Protection Research; 2013, 53, 1
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bee Pollen as a Functional Product – Chemical Constituents and Nutritional Properties
Autorzy:
Alshallash, Khalid S.
Abolaban, Gomaa
Elhamamsy, Sam M.
Zaghlool, Ayman
Nasr, Ali
Nagib, Ashraf
Abd El-Hakim, Ahmed F.
Zahra, Abdullah A.
Hamdy, Ashraf E.
Taha, Ibrahim M.
Powiązania:
https://bibliotekanauki.pl/articles/2202357.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
eucalyptus
clover
maize
phenolic content
amino acid
pollen
Opis:
Nutritional supplements play a role in promoting human protein synthesis, fitness recovery, and mental health protection. Pollen is considered a natural food with excellent nutritional value. The use of bee-gathered pollen as a nutritional supplement is now widespread around the world, and it is appreciated for its healing qualities. However, depending on the floral species and the region of origin, pollen has a wide range of nutritional value. It was found that clover pollen had the highest protein content (31.4 g/100 g DM), while the lowest content was observed in maize pollen (21.3%). Eucalyptus pollen had the highest lipid amount (9.49 g/100 g DM), while clover pollen had the lowest content (7.46 g/100 g). Phytochemical analysis showed that eucalyptus pollen occupied the highest total antioxidant activity (67.02%), followed by clover (58.25%) then maize (52.18%), whereas clover pollen had the highest phenolic content (1165 mg GAE/100 gm), compared with the other pollen varieties (949.4 to 1073 mg-GAE/100 gm). The contents of branched-chain amino acids were 29, 33.3, and 38.4 mg/g for maize, eucalyptus, and clover respectively, representing 17.87, 18.44, and 16.53% of total amino acids. The contents of total essential amino acids (EAAs) were 61.8, 73.0, and 83.5 mg/g for maize, eucalyptus, and clover pollen, respectively. Only eucalyptus pollen ultimately met the minimum requirements of EAAs for adults. In contrast, the other two types of pollen contained at least 3–4 limiting amounts of the essential amino acids leucine, lysine, phenylalanine, and valine. In conclusion, pollen is a good, affordable source of nutrients that can be utilized as beneficial dietary supplements for human health.
Źródło:
Journal of Ecological Engineering; 2023, 24, 2; 173--183
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The light microscopy and ultrastructural characteristics of Myxobolus naffari (Myxosporea, Myxobolidae) infecting the Nile carp Labeo niloticus (Cyprinidae) and its histological impact
Autorzy:
Ardalan, Naksheen M.
Al-Hashimi, Salam F.
El Garhy, Manal
Hamdi, Salwa A.H.
Al Ghamdi, Ali
Morsy, Kareem
Powiązania:
https://bibliotekanauki.pl/articles/972261.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Parazytologiczne
Tematy:
parasite
morphology
ultrastructure
Myxobolus naffari
Myxosporea
Labeo niloticus
Opis:
During a survey of myxosporean parasites infecting freshwater fishes from the River Nile at Giza Governorates, Egypt between March and September 2016, nine out of 30 specimens of the Nile carp Labeo niloticus (Cyprinidae) were found to be naturally infected with Myxobolus naffari (Myxobolidae). Small macroscopic plasmodia appeared embedded in the host gill tissue accompanied with fusion of the gill epithelia, and atrophy was observed at the site of infection. The host reaction was manifested by the encapsulation of the plasmodia with a thick layer of connective tissue. The plasmodia appeared as white, elongated rods between gill filaments with an intensity ranging from three to eight cysts/fish. The average dimensions of plasmodia were 1.2–2.0 (1.8 ± 0.2) mm long × 0.4–0.7 (0.6 ± 0.2) mm wide. The spores were oval, reaching 9.56–11.2 (10.2 ± 0.2) μm long and 6.5–7.7 (7.0 ± 0.4) μm wide with two equal-sized polar capsules regularly arranged at the anterior pole of each spore. They were 4.51–5.5 (5.1 ± 0.4) μm in length and 1.5–2.0 (1.7 ± 0.2) μm in width. Histological, semi-thin sections were taken through parasite plasmodia and transmission electron microscopic examination of ultrathin sections was performed to describe the developmental stages of the recorded parasite within the host fish.
Źródło:
Annals of Parasitology; 2017, 63, 3; 159-165
0043-5163
Pojawia się w:
Annals of Parasitology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Production of bioactive metabolites from different marine endophytic Streptomyces species and testing them against methicillin-resistant Staphylococcus aureus (MRSA) and cancer cell lines
Autorzy:
El-Gendy, M.M.A.A.
Mohamed, Z.K.
Hekal, N.Z.
Ali, F.M.
Yousef, A.E.M.
Powiązania:
https://bibliotekanauki.pl/articles/81078.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Staphylococcus aureus
infection
methicillin-resistant Staphylococcus aureus
endophyte
Streptomyces
bioactive metabolite
Actinomycetes
marine invertebrate
anticancer activity
cancer cell line
lung cancer
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2018, 99, 1
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Correlation between Solar Flare Phenomena in an X-ray Region and Radio Flux Measurement from January to September 2010
Autorzy:
Hamidi, Z. S.
Shariff, N. N. M.
Ali, M. F.
Monstein, C.
Zulkifli, W. N. A. W.
Ibrahim, M. B.
Arifin, N. S.
Amran, N. A.
Powiązania:
https://bibliotekanauki.pl/articles/411743.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
sun
chromospheres
flares
radio flux
solar activity
Opis:
A short term variation of solar flare in nine months (January 2010 to September 2010) is presented. This paper review and analyze the correlation between radio flux strength measurement and solar flare in the X-ray region. The radio flux measurement data were taken from the National Research Council; Ottawa while hard X-ray emission observed by Royal Observatory of Belgium. The overall range of solar radio flux recorded in this study ranging from 68 x 10-22 Wm-2Hz-1 to 96 x 10-22 Wm-2Hz-1. As there was no class of an X of solar flare reported at all in this study, we can confirm that there are no major effects that happened on Earth and outer space such as Coronal Mass Ejections (CMEs) and solar storms. We concluded that the Sun shows a very minimum activity towards 24th solar cycle.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 9; 84-92
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of the density and cumulative distribution functions of the exponentiated Burr XII distribution
Autorzy:
Hassan, Amal S.
Assar, Salwa M.
Ali, Kareem A.
Nagy, Heba F.
Powiązania:
https://bibliotekanauki.pl/articles/1917020.pdf
Data publikacji:
2021-12-08
Wydawca:
Główny Urząd Statystyczny
Tematy:
exponentiated Burr Type XII model
least squares estimator
maximum likelihood estimator
uniform minimum variance unbiased estimator
weighted least squares estimator
Opis:
The exponentiated Burr Type XII (EBXII) distribution has wide applications in reliability and economic studies. In this article, the estimation of the probability density function and the cumulative distribution function of EBXII distribution is considered. We examine the maximum likelihood estimator, the uniformly minimum variance unbiased estimator, the least squares estimator, the weighted least squares estimator, the maximum product spacing estimator, the Cramér–von-Mises estimator, and the Anderson–Darling estimator. We derive analytical forms for the bias and mean square error. A simulation study is performed to investigate the consistency of the suggested methods of estimation. Data relating to the wind speed and service times of aircraft windshields are used with the studied methods. The simulation studies and real data applications have revealed that the maximum likelihood estimator performs more efficiently than its remaining counterparts.
Źródło:
Statistics in Transition new series; 2021, 22, 4; 171-189
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Plants take action to mitigate salt stress: Ask microbe for help, phytohormones, and genetic approaches
Autorzy:
Hewedy, Omar A.
Mahmoud, Ghada Abd-Elmonse
Elshafey, Naglaa F.
Khamis, Galal
Karkour, Ali M.
Abdel Lateif, Khalid S.
Amin, Basma H.
Chiab, Nour
El-Taher, Ahmed M.
Elsheery, Nabil I.
Powiązania:
https://bibliotekanauki.pl/articles/2174285.pdf
Data publikacji:
2022
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
Bacillus
ion homeostasis
osmoprotectants
osmotic stress
photosynthesis
ROS scavenging
Opis:
Global agriculture is a pivotal activity performed by various communities worldwide to produce essential human food needs. Plant productivity is limited by several factors, such as salinity, water scarcity, and heat stress. Salinity significantly causes short or long-term impacts on the plant photosynthesis mechanisms by reducing the photosynthetic rate of CO2 assimilation and limiting the stomatal conductance. Moreover, disturbing the plant water status imbalance causes plant growth inhibition. Up-regulation of several plant phytohormones occurs in response to increasing soil salt concentration. In addition, there are different physiological and biochemical mechanisms of salt tolerance, including ion transport, uptake, homeostasis, synthesis of antioxidant enzymes, and osmoprotectants. Besides that, microorganisms proved their ability to increase plant tolerance, Bacillus spp. represents the dominant bacteria of the rhizosphere zone, characterised as harmless microbes with extraordinary abilities to synthesise many chemical compounds to support plants in confronting salinity stress. In addition, applying arbuscular mycorrhizal fungi (AMF) is a promising method to decrease salinity-induced plant damage as it could enhance the growth rate relative to water content. In addition, there is a demand to search for new salt-tolerant crops with more yield and adaptation to unfavourable environmental conditions. The negative impact of salinity on plant growth and productivity, photosynthesis, stomatal conductance, and changes in plant phytohormones biosynthesis, including abscisic acid and salicylic acid, jasmonic acid, ethylene, cytokinins, gibberellins, and brassinosteroids was discussed in this review. The mechanisms evolved to adapt and/or survive the plants, including ion homeostasis, antioxidants, and osmoprotectants biosynthesis, and the microbial mitigate salt stress. In addition, there are modern approaches to apply innovative methods to modify plants to tolerate salinity, especially in the essential crops producing probable yield with a notable result for further optimisation and investigations.
Źródło:
Journal of Water and Land Development; 2022, 55; 1--16
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Climate change necessitates a change in the cultivation date of caraway (Carum carvi L.)
Autorzy:
Ibrahim, Mostafa Fathi
Ali, Muhammad Moaaz
Lamlom, Sobhi F.
Kalaji, Hazem M.
Yousef, Ahmed F.
Powiązania:
https://bibliotekanauki.pl/articles/2174359.pdf
Data publikacji:
2022
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
climate change
condiment
leafy vegetable
sowing time
vegetative growth
volatile oil
Opis:
By 2050, global crop demand is projected to rise by 60-110%. Crop yields have also been impacted by cli mate change in some nations, and these impacts are likely to continue. To prevent the influence of climate change on crop output, it is critical to adjust planting times in weather-related open fields to meet food security concerns. Present study was carried out at Experimental Farm of Faculty of Agriculture, Al-Azhar University, Assiut, Egypt, during two successive seasons, 2019 and 2020. It was aimed to study the effect of different sowing times (1st and 15th October, 1st and 15th November), and plant spacings (25, 20, and 15 cm) on growth, fruit yield, and oil production of caraway (Carum carvi L.) plants. The results showed that sowing caraway plants on 15th October with plant spacing of 25 cm gave the highest dry weight (72.6 g∙plant-1), fresh weight (266.15 g∙plant-1), seed yield (37.43 g∙plant-1), and oil yield (0.659 cm 3∙plant-1). The maximum umbels (50.83 number per plant) and essential oil (1.78%) were also recorded in the plants receiving same treatment. On the other hand, plants sown at 15th November with spacing of 15 cm exhibited the minimum values of recorded traits. While the highest value of plant height gave with sowing caraway plants on 15th October with plant spacing of 15 cm (135.35 cm). In conclusion, the plants sowed on October 15th with a maximum plant spacing of 25 cm had the highest values of the evaluated morphological, biochemical, and yield attributes of caraway.
Źródło:
Journal of Water and Land Development; 2022, 54; 38--47
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The efficiency of some fungi species in wastewater treatment
Autorzy:
Kadhim, Nuha F.
Mohammed, Wathiq J.
Al Hussaini, Ibtihal M.
Al-Saily, Hala M.N.
Ali, Rasha N.
Powiązania:
https://bibliotekanauki.pl/articles/1841944.pdf
Data publikacji:
2021
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
bioremediation
fungi
nitrite
phosphate
wastewater
Opis:
Using microorganisms in eliminating or reducing the impacts of harmful remnants is very ancient manner. The current study was conducted to explore the potential of utilizing some fungi species that isolated from the main sewage treatment plant in Al-Muamirah area, Babylon-Iraq, in reducing some pollutants. Six fungi taxa Aspergillus flavus, A. niger, A. terrues, Candida albicans, C. krusei, and Penicillium digitatum were identified before any treatment process, whereas only four fungi species A. flavus 20%, A. niger 20%, A. terrues 10%, and P. digitatum 18% were recognized after completing the physical and chemical treatment stages. Only three taxa A. niger, A. terrues, and P. digitatum were employed to reveal their capability in treating the sewage water, which represent the biological treatment stage as the final step of the treatment processes. The results showed a considerable capability of these fungi species in decreasing many variables values such as pH, total soluble solids (TSS), electrical conductivity (EC), salinity, total alkalinity, chlorides, nitrite, and phosphate. Where, slightly low reduction was detected in TSS value in all experiments (1.1–5.9%), similarly, both EC and salinity which were decreased with low ratios (6.6%, 3.9%, respectively). Taxon A. terrues exhibited high ability in reducing the total alkalinity and chloride ions in the treated water (30.9%, 43%, respectively) in comparison with the other two fungi species. Furthermore, all three fungi species were posed high capability in decreasing nutrients, where both nitrite and phosphate ions were highly reduced (87–97% and 22.8–32.1%, respectively). Based on these findings, we suggest using other microorganisms and exploring their capacity in removing the pollutants, and revealing the ability of the above fungi taxa in removing other pollutants.
Źródło:
Journal of Water and Land Development; 2021, 50; 248-254
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Three-Axis Attitude Estimation Of Satellite Through Only Two-Axis Magnetometer Observations Using LKF Algorithm
Autorzy:
Mehrjardi, M. F.
Sanusi, H.
Ali, M. A. M.
Powiązania:
https://bibliotekanauki.pl/articles/221622.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
satellite three-axis attitude estimation
two-axis magnetometer
observations
LKF
PD controller
Opis:
Estimation of satellite three-axis attitude using only one sensor data presents an interesting estimation problem. A flexible and mathematically effective filter for solving the satellite three-axis attitude estimation problem using two-axis magnetometer would be a challenging option for space missions which are suffering from other attitude sensors failure. Mostly, magnetometers are employed with other attitude sensors to resolve attitude estimation. However, by designing a computationally efficient discrete Kalman filter, full attitude estimation can profit by only two-axis magnetometer observations. The method suggested solves the problem of satellite attitude estimation using linear Kalman filter (LKF). Firstly, all models are generated and then the designed scenario is developed and evaluated with simulation results. The filter can achieve 10e-3 degree attitude accuracy or better on all three axes.
Źródło:
Metrology and Measurement Systems; 2015, 22, 4; 577-590
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inverse Hall-Petch Like Mechanical Behaviour in Nanophase Al-Cu-Fe Quasicrystals: A New Phenomenon
Autorzy:
Mukhopadhyay, N.
Ali, F.
Scudino, S.
Samadi Khoshkhoo, M.
Stoica, M.
Srivastava, V.
Uhlenwinkel, V.
Vaughan, G.
Suryanarayana, C.
Eckert, J.
Powiązania:
https://bibliotekanauki.pl/articles/1373423.pdf
Data publikacji:
2014-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.44.Br
Opis:
The structural and mechanical stability of quasicrystals are important issues due to their potential for possible applications at high temperatures and stresses. The aim of the present work is, therefore, to review the earlier works on conventional crystalline and quasicrystalline materials and also to report the results and the analysis on the Hall-Petch and inverse Hall-Petch like behavior of nanoquasicrystalline $Al_{62.5}Cu_{25}Fe_{12.5}$ alloys. It was observed that, at large grain sizes, the hardness increases with decreasing grain size, exhibiting the conventional Hall-Petch relationship, whereas for smaller grains, inverse Hall-Petch behavior was identified. The inverse Hall-Petch behavior in the nanoquasicrystalline phase could be attributed to thermally activated shearing of the grain boundaries, leading to grain boundary sliding in nanostructures of quasicrystalline grains. These results were analyzed based on the dislocation pile-up model as well as the grain boundary shearing models applicable to nanomaterials.
Źródło:
Acta Physica Polonica A; 2014, 126, 2; 543-548
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical properties and microstructure of alkali activated mortar containing unexpanded clay
Autorzy:
Nasser, I.F.
Ali, M.A.
Kadhim, M.J.
Powiązania:
https://bibliotekanauki.pl/articles/2201132.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
alkali-activated mortar
pozzolan
unexpanded clay
flexural toughness
scanning electron microscope
thermal insulation
pucolana
glina nie spulchniona
wytrzymałość na zginanie
skaningowy mikroskop elektronowy
izolacja termiczna
Opis:
Purpose: In building constructions, due to the decrease of local raw materials and for sustainability purpose, beside the need of light pieces to be used in roofing and false ceiling; an alkali-activated mortar is the new development where pozzolanic material is used instead of cement and activated by an alkaline solution. Therefore, in this research, alkali-activated mortar containing unexpanded clay as a fine aggregate with a dry density of 1652 kg/m3, compressive strength of 3.2 MPa, and thermal conductivity of 0.4 (W/m.K) was produced ,also boards were performed in a dimension of 305×152×12 mm as to use them in false ceiling, and reinforced with 0.25 and 0.5% steel fibre to improve their toughness by 370.8% and 1146.1% compared with reference boards, which made them good choice to used them in roofing and secondary ceiling. Design/methodology/approach: For preparation of alkali-activated mortar, low calcium fly ash (FA) was used as a source binder material. In addition, super-plasticizer and unexpanded clay as a fine aggregate (produce from the crushed artificial aggregate) in the ratio of 1:2.75 fly ash/fine aggregate. The paste was prepared by mixing fly ash with an alkali silicate solution, in a solid-to-liquid ratio of 0.4. Alkali silicate activator was prepared by mixing the NaOH and Na2SiO3 solutions at the mass ratios of 2.5. The concentrations of the NaOH was the same molarity of (14M).To improve the mechanical properties of the reference mortar mixture ,steel fibre with 0.25 and 0.5% content were added to the mix .The specimens were tested for water absorption, dry density, compressive strength, flexural strengths, flexural toughness, and thermal conductivity, in addition to the Scanning Electron Microscope test (SEM) for all mortar mixes. Alkali-activated mortar boards with (305×152×12 mm) were prepared and tested for flexural strength and toughness. Findings: The results indicated that the modulus of rupture for mortar boards reinforced with 0.25 and 0.5% steel fibre exhibits an increase of (3.68-12.10)%. In comparison, the toughness is increased by about 370.8% and 1146.1%, respectively, as compared with the reference mortar (without fibre) which made them resistance to accident, in addition to use them in roofing due to their thermal insulation. Research limitations/implications: Further research is needed to make a similar board using another sustainable material. We can examine the thermal insulation that we can get from these board, especially in the building in Iraq which the weather faces high temperatures. Practical implications: There is a by-product that we could get from the electricity station in Iraq. We must study how we get rid of it. Originality/value: This paper investigate how to produce a new light board using artificial aggregate made from unexpanded clay, which has many benefits in building insulation roofing.
Źródło:
Archives of Materials Science and Engineering; 2022, 113, 2; 56--68
1897-2764
Pojawia się w:
Archives of Materials Science and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-15 z 15

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