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Tytuł:
Long wavelength type-II superlattice barrier infrared detector for CubeSat hyperspectral thermal imager
Autorzy:
Rafol, Sir B.
Gunapala, Sarath D.
Ting, David Z.
Soibel, Alexander
Khoshakhlagh, Arezou
Keo, Sam A.
Pepper, Brian J.
Hill, Cory J.
Maruyama, Yuki
Fisher, Anita M.
Sood, Ashok
Zeller, John
Wright, Robert
Lucey, Paul
Nunes, Miguel
Flynn, Luke
Babu, Sachidananda
Ghuman, Parminder
Powiązania:
https://bibliotekanauki.pl/articles/2204204.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
type-II superlattice
focal plane array
infrared detector
quantum efficiency
noise equivalent difference temperature
dark current density
anti-reflective coating
Opis:
The hyperspectral thermal imaging instrument for technology demonstration funded by NASA’s Earth Science Technology Office under the In-Space Validation of Earth Science Technologies program requires focal plane array with reasonably good performance at a low cost. The instrument is designed to fit in a 6U CubeSat platform for a low-Earth orbit. It will collect data on hydrological parameters and Earth surface temperature for agricultural remote sensing. The long wavelength infrared type-II strain layer superlattices barrier infrared detector focal plane array is chosen for this mission. With the driving requirement dictated by the power consumption of the cryocooler and signal-noise-ratio, cut-off wavelengths and dark current are utilized to model instrument operating temperature. Many focal plane arrays are fabricated and characterised, and the best performing focal plane array that fulfils the requirements is selected. The spectral band, dark current and 8-9.4 μm pass band quantum efficiency of the candidate focal plane array are: 8-10.7 μm, 2.1∙10ˉ⁵ A/cm², and 47%, respectively. The corresponding noise equivalent difference temperature and operability are 30 mK and 99.7%, respectively. Anti-reflective coating is deposited on the focal plane array surface to enhance the quantum efficiency and to reduce the interference pattern due to an absorption layer parallel surfaces cladding material.
Źródło:
Opto-Electronics Review; 2023, 31, Special Issue; art. no. e144569
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sea ice mechanics
Autorzy:
Paul, Felix
Schwarz, Carina
Audh, Riesna Reuben
Bluhm, J.
Johnson, Siobhan
MacHutchon, Keith
Mielke, Tommy
Mishra, A.
Rampai, Tokoloho
Ricken, Tim
Schwarz, Alexander
Skatulla, Sebastian
Thom, Andrea
Verrinder, Robyn
Schröder, Jörg
Vichi, Marcello
Lupascu, Doru C.
Powiązania:
https://bibliotekanauki.pl/articles/29519762.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
sea ice mechanics
polar regions
review
Antarctic MIZ
Opis:
Earth System Models (ESM), simulating sea ice and its interaction with the atmosphere and open ocean, require reliable physical, chemical, and biological input from measurements. There is limited data available from the Marginal Ice Zone of the Antarctic, where sea ice growth mechanisms differ from the Arctic. The main objective of this study is to review existing work related to Antarctic sea ice and highlight gaps in the available literature. The mechanical properties of sea ice and the numerical modeling of sea ice across all scales are covered. We summarize the genesis, physical mechanics, static and dynamic properties, strength, toughness, and transport of young sea ice as well as medium to large scale observation. On the computational mechanics side large- and small-scale modeling, ocean-sea ice and atmosphere-sea ice models, as well as sea ice rheology models, sea ice fracture mechanics, and bio-geo-chemical interaction processes are captured. The synergy between the physical and computational mechanics brings to light missing information from both fields. Plain language summary (PLS) Sea ice determines the interaction of the ocean with the atmosphere in both the southern and northern hemispheres. Its formation and annual development is subject to mechanical interaction with ocean currents and winds. This review covers the mechanics of sea ice in the Antarctic and its relation to the Arctic covering experiment and modelling. Impact on the climate is discussed.
Źródło:
Computer Methods in Materials Science; 2023, 23, 3; 5-53
2720-4081
2720-3948
Pojawia się w:
Computer Methods in Materials Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biological synthesis and characterization of titanium dioxide nanoparticle from Cynodon dactylon
Autorzy:
Renitta, R. E.
Jebaseeli, T. J.
Dhanaraj, A.
Paul, S.
Powiązania:
https://bibliotekanauki.pl/articles/2201037.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
nanoparticle
Cynodon dactylon
FTIR
SEM
XRD
titanium dioxide
biological synthesis
nanocząstka
Cynodon palczasty
spektroskopia w podczerwieni z transformacją Fouriera
skaningowa mikroskopia elektronowa
dyfrakcja rentgenowska
dwutlenek tytanu
biosynteza
Opis:
Purpose: There are several advantages of using a biological technique to produce nanoparticles versus a chemical method. The primary goal of this work is to characterize and biologically synthesize titanium dioxide (TiO2) nanoparticles from Cynodon dactylon. The characterization has experimented with UV-Vis Spectroscopy, EDX analysis, SEM, XRD, and FTIR. Design/methodology/approach: The suggested study uses a simple biological technique to accomplish the systematic biological synthesis of TiO2 nanoparticles utilizing Cynodon dactylon plant extract and titanium tetra isopropoxide as a precursor. UV-Vis spectroscopy, Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and X-Ray Diffraction (XRD) are used to confirm the fabrication of the TiO2 nanoparticles. The plant extract as well as titanium-based nanoparticles of the herb, Cynodon dactylon will be tested for its antibacterial activity against human pathogens. This eco-friendly technique for nanoparticle synthesis is straightforward and adaptable to major commercial manufacturing and technological applications. Findings: Cynodon dactylon biosynthesis of TiO2 nanoparticles is efficient, nutrition dependent, does not employ hazardous compounds, and happens at neutral pH levels. The antibacterial study results show that TiO2 nanoparticles synthesized using Cynodon dactylon have good antibacterial properties. TiO2 nanoparticle method of action against bacteria is unknown. This is an alternative process for synthesising TiO2 nanoparticles, apart from other chemical protocols, since this is quick and non-toxic. The antimicrobial property of biologically synthesized TiO2 nanoparticles against Escherichia coli, Staphylococcus aureus, and Acinetobacter baumannii was tested at four different doses of 15 μl/mg, 25 μl/mg, 50 μl/mg, and 75 μl/mg. The present results revealed the 75 μl/mg concentration got the highest zone of inhibition (15, 13, 15 mm) for Acinetobacter baumannii, Staphylococcus aureus, and Escherichia coli. Research limitations/implications: Many nanoparticles smaller than 100 nm are firmly agglomerated with each other in the study. TiO2 nanoparticles absorb in the UV region of 200 to 400 nm. XRD measurements confirmed the presence of TiO2 nanoparticles in the biologically produced sample. In our work, EDX was used to confirm the existence of Ti after its synthesis by Cynodon dactylon. Practical implications: The biosynthesized TiO2 nanoparticles utilizing Cynodon dactylon plant extracts exhibit a good potent antibacterial activity. The proposed results showed that the TiO2 nanoparticles are well suited for biomedical applications. Originality/value: The suggested research identifies several eco-friendly, biological, and cost-effective procedures for manufacturing nano-coated herbal products. The agar well diffusion technique was used to assess antibacterial activities toward test pathogens such as Acinetobacter baumannii, Staphylococcus aureus, and Escherichia coli.
Źródło:
Journal of Achievements in Materials and Manufacturing Engineering; 2022, 113, 1; 31--41
1734-8412
Pojawia się w:
Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of Low–power 4-bit Flash ADC Using Multiplexer Based Encoder in 90nm CMOS Process
Autorzy:
Shylu Sam, D. S.
Sam Paul, P.
Jeba Jingle, Diana
Mano Paul, P.
Samuel, Judith
Reshma, J.
Sudeepa, P. Sarah
Evangeline, G.
Powiązania:
https://bibliotekanauki.pl/articles/2124770.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
flash ADC
low power
dynamic comparator
encoder
Opis:
This work describes a 4-bit Flash ADC with low power consumption. The performance metrics of a Flash ADC depend on the kind of comparator and encoder used. Hence openloop comparator and mux-based encoder are used to obtain improved performance. Simulation results show that the simulated design consumes 0.265mW of power in 90nm CMOS technology using cadence-virtuoso software. The circuit operates with an operating frequency of 100MHz and a supply voltage of 1V.
Źródło:
International Journal of Electronics and Telecommunications; 2022, 68, 3; 565--570
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mixup (sample pairing) can improve the performance of deep segmentation networks
Autorzy:
Isaksson, Lars J.
Summers, Paul
Raimondi, Sara
Gandini, Sara
Bhalerao, Abhir
Marvaso, Giulia
Petralia, Giuseppe
Pepa, Matteo
Jereczek-Fossa, Barbara A.
Powiązania:
https://bibliotekanauki.pl/articles/2147117.pdf
Data publikacji:
2022
Wydawca:
Społeczna Akademia Nauk w Łodzi. Polskie Towarzystwo Sieci Neuronowych
Tematy:
magnetic resonance imaging
segmentation
prostate
data augmentation
mixup
Opis:
Researchers address the generalization problem of deep image processing networks mainly through extensive use of data augmentation techniques such as random flips, rotations, and deformations. A data augmentation technique called mixup, which constructs virtual training samples from convex combinations of inputs, was recently proposed for deep classification networks. The algorithm contributed to increased performance on classification in a variety of datasets, but so far has not been evaluated for image segmentation tasks. In this paper, we tested whether the mixup algorithm can improve the generalization performance of deep segmentation networks for medical image data. We trained a standard U-net architecture to segment the prostate in 100 T2-weighted 3D magnetic resonance images from prostate cancer patients, and compared the results with and without mixup in terms of Dice similarity coefficient and mean surface distance from a reference segmentation made by an experienced radiologist. Our results suggest that mixup offers a statistically significant boost in performance compared to non-mixup training, leading to up to 1.9% increase in Dice and a 10.9% decrease in surface distance. The mixup algorithm may thus offer an important aid for medical image segmentation applications, which are typically limited by severe data scarcity.
Źródło:
Journal of Artificial Intelligence and Soft Computing Research; 2022, 12, 1; 29--39
2083-2567
2449-6499
Pojawia się w:
Journal of Artificial Intelligence and Soft Computing Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Serum fluoride levels in ambulance staff after commencement of methoxyflurane administration compared to meta-analysis results for the general public
Autorzy:
Allison, Serah J.
Docherty, Paul D.
Pons, Dirk
Chase, James G.
Powiązania:
https://bibliotekanauki.pl/articles/2093863.pdf
Data publikacji:
2021-12-13
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
meta-analysis
prospective studies
fluorides
ambulances
fluoride poisoning
methoxyflurane
Opis:
ObjectivesAmbulance officers administering methoxyflurane as an inhalational analgesic may be exposed to trace vapor. Fluoride is a methoxyflurane metabolite, and has been associated with acute renal failure in anesthesia patients and skeletal fluorosis with chronic elevated serum levels from other sources. However, there has been no direct measurement of serum fluoride in occupationally exposed ambulance officers. Thus, this study directly measures serum fluoride over a prolonged period in order to determine renal toxic and skeletal fluorosis risk to ambulance officers who are administering methoxyflurane.Material and MethodsSerum inorganic fluoride concentrations were measured in a prospective observational study of 12 emergency medical technicians (EMTs). The study took 7 serum fluoride measurements over 24 months. A meta-analysis of healthy adult serum fluoride ranges was also conducted.ResultsThe typical healthy adult serum fluoride range was determined to be 0.21–2.11 μmol/l (p < 0.001). The EMTs’ baseline median (IQR) serum fluoride concentrations were 0.4 μmol/l (0.2; 1.0) with maximum 1.6 μmol/l. The EMTs’ overall median serum fluoride was 0.4 μmol/l (0.2; 1.3) with maximum 4.0 μmol/l, usually within healthy reference ranges. All results were ≤10% of the suggested single-dose renal toxic threshold. One result was above a threshold for skeletal fluorosis. The highest measured serum fluoride was 24% of the lowest level associated with radiologic evidence of fluorosis. There was no evidence overall of increasing serum fluoride levels.ConclusionsThere was no evidence that EMTs’ exposure to methoxyflurane resulted in sustained increased serum fluoride. These results imply EMTs’ occupational safety from acute renal toxicity when activated carbon filtration is used on patient exhalation. However, 1 serum fluoride result above a skeletal fluorosis threshold suggests that the risk of mild skeletal fluorosis cannot be excluded.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2021, 34, 6; 767-777
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tropical infections as occupational diseases – labor inspectorate physicians’ aspects of a complex problem
Autorzy:
Jansing, Paul J.
Morrison, Audry
Heggie, Travis W.
Küpper, Thomas
Powiązania:
https://bibliotekanauki.pl/articles/2098245.pdf
Data publikacji:
2021-07-20
Wydawca:
Państwowa Wyższa Szkoła Zawodowa w Tarnowie
Tematy:
tropical diseases
occupational diseases
travel medicine
malaria
diagnosis
prevention
surveillance
compensation
Opis:
Background: Occupational physicians work directly with individual employees regarding diseases that has been caused or exacerbated by workplace factors. However, employees are increasingly required to travel for their work, including to tropical countries where they risk exposure to diseases they would not normally encounter at home (i.e., malaria). Such disease/s may also take days to months to incubate before becoming symptomatic, even after their return home, thus delaying and complicating the diagnosis. Proving this was an occupational disease with respective sick leave entitlement or compensation can be challenging. There is a lack of data concerning occupational diseases caused by tropical infections.Material and methods: Employee case records for the period 2003-2008 from the State Institute for Occupational Health and Safety of North-Rhine Westphalia in Germany were analysed and assessed within Germany’s regulatory framework. These records included Germany’s largest industrial zone.Results: From 2003-2008the suspected cases of “tropical diseases and typhus”, categorized as occupational disease “Bk 3104” in Germany, have decreased significantly. A high percentage of the suspected cases was accepted as occupational disease, but persistent or permanent sequelae which conferred an entitlement to compensation were rare.Conclusion: There is scope to improve diagnosis and acceptance of tropical diseases as occupational diseases. The most important diseases reported were malaria, amoebiasis, and dengue fever. Comprehensive pre-travel advice and post-travel follow-ups by physicians trained in travel and occupational health medicine should be mandatory. Data indicate that there is a lack of knowledge on how to prevent infectious disease abroad.
Źródło:
Health Promotion & Physical Activity; 2021, 15, 2; 21-28
2544-9117
Pojawia się w:
Health Promotion & Physical Activity
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental investigation on elevated water tanks with base isolation – response spectrum approach
Autorzy:
Vimal, Paul P. A.
Regin, Joseph D. J.
Jinu, Gowthami T. R.
Chettiar, Chembakaraman G.
Powiązania:
https://bibliotekanauki.pl/articles/1839602.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
response spectrum
base isolation
natural time period
base shear
spectral
acceleration
Opis:
Elevated water tanks in an empty condition, though not important in structural design, becomes an important problem in seismic design. The objective of the present research is to investigate the elevated water tanks in empty and in filled conditions and to emphasize the importance of seismic response. Four elevated tanks with various parameters are selected for seismic analysis with the base isolation technique. It is found out that empty tanks are highly vulnerable to earthquake effects, whereas filled tanks can be mitigated by providing base isolation. A simple experimental investigation has also been carried out to validate the analytical results.
Źródło:
Journal of Theoretical and Applied Mechanics; 2020, 58, 4; 885-899
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gaps in the Saturation Spectrum of Trees
Autorzy:
Horn, Paul
Gould, Ronald J.
Jacobson, Michael S.
Thomas, Brent J.
Powiązania:
https://bibliotekanauki.pl/articles/31343596.pdf
Data publikacji:
2019-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
saturation spectrum
tree
saturation number
Opis:
A graph G is H-saturated if H is not a subgraph of G but the addition of any edge from the complement of G to G results in a copy of H. The minimum number of edges (the size) of an H-saturated graph on n vertices is denoted sat(n,H), while the maximum size is the well studied extremal number, ex(n,H). The saturation spectrum for a graph H is the set of sizes of H-saturated graphs between sat(n,H) and ex(n,H). In this paper we show that paths, trees with a vertex adjacent to many leaves, and brooms have a gap in the saturation spectrum.
Źródło:
Discussiones Mathematicae Graph Theory; 2019, 39, 1; 157-170
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phytochemical screening and in vitro antimicrobial properties of Annona muricata extracts against certain human pathogens
Autorzy:
Oluyege, J.O.
Orjiakor, Paul Ikechukwu
Badejo, O.E.
Powiązania:
https://bibliotekanauki.pl/articles/135020.pdf
Data publikacji:
2019
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
Annona muricata
pathogens
bacteria
fungi
antibiotics
medicinal plants
Opis:
All over the world, the use of medicinal plants is gaining more acceptability due to the possibility of discovering novel drugs from them and solving the problem of antimicrobial resistance associated with conventional antibiotics. The phytochemical composition and antimicrobial properties of crude extracts of the leaves, stems, and bark of Annona muricata were evaluated on Escherichia coli, Staphylococcus aureus, and Salmonella typimurium, while the antifungal properties were evaluated against Candida albicans and Candida tropicalis. The Agar well method was used for the study. At concentrations of 150 mg/ml and 300 mg/ml, inhibitory effects were observed on E. coli and S. aureus, with a visible zone of inhibition ranging from 15 mm to 21 mm respectively, and with respect to N- hexane, an antimicrobial activity range of 5 mm to 20 mm, for the leaf extract, which shows effective antimicrobial action against E. coli and S. aureus. Hot water extracts were observed to possess more bioactive compounds compared to organic solvent extracts, and exhibit higher ranges of activity against the tested bacterial species. All extracts exhibited low anti-fungal activity in the range of 8 mm to 15 mm. The phytochemical screening of the extracts of different parts of A. muricata revealed the presence of secondary metabolites such as tannins, alkaloids, saponins, flavonoids, steroids, and cardiac glycosides. The antimicrobial activity of the extracts was compared with a standard antibiotic, ketoconazole, and with ampicillin, which served as the controls). The results showed that A. muricata can be used as an anti-bacterial substance, since it shows broad spectrum activity against a range of bacteria responsible for the most common bacterial illnesses. Further research will be necessary to ascertain its full spectrum of efficacy.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2019, 60 (132); 203-209
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Validity of Human Rights in Europe in the Wake of the Crisis of Refugees from the Middle East
Autorzy:
Ibarra Martínez, Jorge R.
Cota Navarro, Paul J.
Powiązania:
https://bibliotekanauki.pl/articles/969447.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Warszawski. Centrum Europejskie
Tematy:
Human Rights;
Social Movements;
Refugees;
Opis:
The purpose of this article is to analyse the loss of validity in the principles of universality and equality that lead the international system of Human Rights, in the wake of the refugee crisis that arose in Europe in 2014. The main idea is that the massive arrival of refugees due to the violence in the Middle East revealed severe humanitarian contradictions in the European countries when providing the right to asylum, integration, acknowledgementand i ntercultural dialogue in favour of those affected by the war.T hrough an analysis of the debates that arose in Europe after the arrival of refugees to the continent, this article seeks to evidence the diminishmentin the social support to the values of freedom, international cooperation, multiculturalism and Human Rights; as well as an increase in the xenophobic and isolationist expressions. This work approaches the situation of Human Rights from the theoretical perspective of social movements, bearing in mind that the progressiveincorpor ation of these prerogatives in the national and international legal frameworks, has been encouraged by collective actions that generationally have managed to increase the repertoire of rights that protect human dignity. Nevertheless, the inconvenience now, is that regressive movements have begun to arise nowadays, threatening to move aside institutions that behold the ideal of a liberal and cosmopolitan democracy. To state evidence of such challenge, this work compiles the opinion of the European population in topics that refl ect their point of view on Human Rights. In this context, the research methodology was oriented to discourse analysis of online comments posted by readers of the newspapers with the highest circulation in six European countries, in relation to news that, because of their impact, appalled society and made them take part in the repercussions for their countries.
Źródło:
Studia Europejskie - Studies in European Affairs; 2019, 3; 133-151
1428-149X
2719-3780
Pojawia się w:
Studia Europejskie - Studies in European Affairs
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A report on the Lemko Association and the Carpathian Institute of the USA in 2017
Autorzy:
Best, Paul J.
Powiązania:
https://bibliotekanauki.pl/articles/450379.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
Lemko Association
Carpathian Institute
Lemkos
United States of America
Opis:
This paper reports on the recent revival of the Lemko Association (Lemko Soyuz) in North America, under the auspices of the Carpathian Institute, a US federal and Connecticut state recognized tax-exempt, non-profit, non-political, non-sectarian educational corporation. The Lemko Association, founded in 1929, had become essentially defunct by the end of 2009. Beginning in 2010, however, in a new location and new legal status it has been revived, publishing a quarterly, “Karpatska Rus’”, books, pamphlets and flags and arranging for lectures.
Źródło:
Przegląd Narodowościowy – Review of Nationalities; 2018, 8; 293-300
2084-848X
Pojawia się w:
Przegląd Narodowościowy – Review of Nationalities
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Corrosion behavior of ZrC particles reinforcement with Al-12Si composites by weight loss method using acidic media
Autorzy:
John, C. F.
Paul, R. C.
Singh, S. C. E.
Jacobjose, J.
Ramkumar, T.
Hikku, G. S.
Sharma, R. K.
Sengottuvel, P.
Powiązania:
https://bibliotekanauki.pl/articles/200059.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Al-Si-ZrC composites
powder metallurgy
weight loss method
corrosion rate
SEM
kompozyty Al-Si-ZrC
metalurgia proszków
metoda redukcji masy
szybkość korozji
Opis:
This paper aims to investigate the corrosion behavior of zirconium carbide (ZrC) reinforced Al – Si metal matrix composites (MMCs) in a mixture of acidic solution using weight loss method. The composites are prepared by powder metallurgy method. Al-12Si-xZrC composites containing 0, 5, and 10 weight percentage of ZrC particles are compacted in a die set assembly and sintered in an inert gas muffle furnace. The acidic solutions used for corrosion are 1 N HCl, 1 N H2SO4 and 1 N HNO3. The corrosion characteristics of Al-12Si-xZrC composites and the pure Al were experimentally evaluated. The corrosion test was carried out at different weight proportions of the samples in various concentrations of the acid such as 1 N HCl, 1 N H2SO4 and 1 N HNO3 for different exposure time (i.e., 24 h, 72 h, 144 h and 216 h), respectively. The results specified that corrosion rate of composites was lower than that of base metal Al under the corrosive atmosphere, regardless of exposure time and acidic solutions used as corrodents. Al-12Si-xZrC composites become more corrosion resistant as the ZrC content is increased. This is because of the development of stable oxide layer above the specimens. Scanning electron microscopy (SEM) confirms the degree of attack of acidic solution on the surface of the examined material.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 1; 9-16
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low genetic diversity of declining Viola uliginosa (Violaceae) at its southern range limits in Poland
Autorzy:
Paul, W.
Cieslak, E.
Ronikier, M.
Migdalek, G.
Slomka, A.
Zabicka, J.
Powiązania:
https://bibliotekanauki.pl/articles/19351.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
Viola uliginosa (bog violet) is a declining species throughout its range due to – mostly anthropogenic – drying out of the wet habitats it occupies. Using AFLP markers, we aimed to estimate the genetic diversity in Polish populations, that may give an insight into the situation of plant populations facing rapid loss of natural habitats. Bog violet from several dispersed Polish populations is generally characterized by very low genetic diversity (HT = 0.048), even lower than several other endangered violets; therefore, we suggest that it should preserve at least EN rank in the red lists/red data books. The mean gene diversity within all populations (HS) was much lower than gene diversity (GST) between populations (0.020 versus 0.583, respectively) which supports the prevalence of clonal propagation of the species (mainly by stolons) but may also point to some significance of autogamy in cleisto- and chasmogamous flowers. A high FST value and the Mantel test for all populations revealed significant isolation by distance. Geographically neighboring pairs of populations formed genetic clusters supported by all (in the case of two closest populations) or most statistical analyses applied. Special attention should be paid to the locus classicus of the species in Rząska, consisting of a small number of individuals, forming a genetically distinct group, revealing very low gene diversity (Hj = 0.009) and the longest genetic distance to the remaining populations. Our results can contribute to planning future protection measures for the species at this and other locations. Genetic structure of the studied populations suggests local affinities of populations but does not generally support hypothesized recent continuity of V. uliginosa range along the river valleys of southern Poland; this view may, however, be altered with widening of the scope of studied populations and chosen molecular markers.
Źródło:
Acta Biologica Cracoviensia. Series Botanica; 2016, 58, 2
0001-5296
Pojawia się w:
Acta Biologica Cracoviensia. Series Botanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Massive peripheral microfilariaemia in a case of human subcutaneous dirofilariasis
Autorzy:
Kludkowska, M.
Pielok, L.
Frackowiak, K.
Masny, A.
Golab, E.
Paul, M.
Stefaniak, J.
Powiązania:
https://bibliotekanauki.pl/articles/6098.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Parazytologiczne
Tematy:
massive peripheral microfilariaemia
microfilariaemia
subcutaneous dirofilariasis
dirofilariasis
human disease
parasitic disease
parasite
nematode
Dirofilaria
Dirofilaria repens
Dirofilaria immitis
Źródło:
Annals of Parasitology; 2016, 62, Suppl.
0043-5163
Pojawia się w:
Annals of Parasitology
Dostawca treści:
Biblioteka Nauki
Artykuł

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