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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:
An Approach to Secure Communication in IoT (Internet of Things)
Autorzy:
Ali Ahammed, G. F.
Banu, Reshma
Fathima, Nasreen
Powiązania:
https://bibliotekanauki.pl/articles/1193541.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
6LoWPAN
Bootstrapping
IETF
IoT
threats
Opis:
The term Internet of Things (IoT) refers to the use of standard internet protocols for interaction between human to things or things to things in an embedded network. Although the security needs are well-recognized, it is still not fully clear how existing IP-based security protocols can be applied to this new setting. In this paper we discuss the various security challenges in an IoT system. The paper also provides a standard IP-based security protocols and its implementation model which can be used as a security system for IoT.
Źródło:
World Scientific News; 2016, 41; 27-33
2392-2192
Pojawia się w:
World Scientific News
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:
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:
Debt maturity and family related directors : evidence from a developing market
Zapadalność zadłużenia i dyrektorzy związani z rodziną : dowody z rozwijającego się rynku
Autorzy:
Hussain, H. I.
Abidin, I. S. Z.
Ali, A.
Kamarudin, F.
Powiązania:
https://bibliotekanauki.pl/articles/404736.pdf
Data publikacji:
2018
Wydawca:
Politechnika Częstochowska
Tematy:
debt maturity
capital structure
family related directors
board composition
corporate governance
family firms
zapadalność zadłużenia
struktura kapitałowa
dyrektorzy rodzinni
skład zarządu
ład korporacyjny
firmy rodzinne
Opis:
This paper examines the debt maturity structures of Malaysian firms based on the presence of family-related directors (FRDs) on boards. The motivation is derived from the board composition literature, which highlights reforms taken place over the years in order to ensure proper governance mechanisms. Conversantly, debt maturities are also linked to reductions in agency costs whereby firms with short-term borrowings will be subject to greater levels of monitoring by markets. Furthermore, this reduces information asymmetry. Thus, the paper evaluates the effectiveness of FRDs in alleviating the agency problem by studying the trade-off of such presence on debt maturity structures. The study finds that firms with the presence of FRDs tend to opt for longer maturity structures. These points towards a substitution effect where firms with FRDs will not rely on short-term borrowing as a mechanism for reducing agency problems. The findings of the study are further validated given that the presence of FRDs is not motivated by firms matching strategy of assets versus liabilities. However, these firms also opt for long-term borrowing in order to mitigate potential liquidity problems. The study further documents that these firms face lower bankruptcy costs. Interestingly, the authors also document that FRD opt to lengthen maturity structures during periods of increase in share prices indicating that control by family members tend to take into consideration shareholders’ wealth maximization. The finding is valid given that most firms with FRD also tend to have significant ownership by families.
W niniejszym artykule przeanalizowano strukturę zapadalności długu malezyjskich firm w oparciu o obecność dyrektorów rodzinnych (FRD) w zarządach. Motywacja pochodzi z literatury poświęconej składom zarządów, która podkreśla reformy, które miały miejsce od lat w celu zapewnienia odpowiednich mechanizmów zarządzania. Konsekwentnie, zapadalność długu jest również powiązana z obniżeniem kosztów pośrednictwa, w wyniku czego firmy o pożyczkach krótkoterminowych będą podlegać większemu monitorowaniu na rynkach. Ponadto zmniejsza to asymetrię informacji. W związku z tym, w artykule dokonano oceny skuteczności FRD w łagodzeniu problemu agencji poprzez zbadanie zysku takiej obecności w strukturach dojrzałości długu. Badanie wykazało, że firmy z obecnością FRD wybierają dłuższe struktury dojrzałości. Wskazuje to na efekt substytucyjny, w którym firmy z FRD nie będą polegać na pożyczkach krótkoterminowych jako mechanizmie zmniejszającym problemy agencji. Wyniki badania są dalej potwierdzane, ponieważ obecność FRD nie jest uzasadniona przez firmy, które dopasowują strategię aktywów do zobowiązań. Firmy te również wybierają długoterminowe pożyczki, aby złagodzić potencjalne problemy z płynnością. Badanie to dokumentuje również, że firmy te ponoszą niższe koszty bankructwa. Co ciekawe, autorzy dokumentują również, że FRD opowiadają się za przedłużeniem struktur zapadalności w okresach wzrostu cen akcji, wskazując, że kontrola członków rodziny ma tendencję do uwzględniania maksymalizacji zamożności akcjonariuszy. Stwierdzenie jest słuszne, biorąc pod uwagę, że większość firm z FRD ma również znaczny udział rodzinny w strukturze własności.
Źródło:
Polish Journal of Management Studies; 2018, 18, 2; 118-134
2081-7452
Pojawia się w:
Polish Journal of Management Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Drilling resistance : A method to investigate bone quality
Autorzy:
Lughmani, W. A.
Farukh, F.
Bouazza-Marouf, K.
Ali, H.
Powiązania:
https://bibliotekanauki.pl/articles/306405.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
chirurgia ortopedyczna
wiercenie
gęstość mineralna kości
jakość kości
bone drilling
orthopaedic surgery
screw pull-out strength
bone mineral density
bone quality
Opis:
Purpose: Bone drilling is a major part of orthopaedic surgery performed during the internal fixation of fractured bones. At present, information related to drilling force, drilling torque, rate of drill-bit penetration and drill-bit rotational speed is not available to orthopaedic surgeons, clinicians and researchers as bone drilling is performed manually. Methods: This study demonstrates that bone drilling force data if recorded in-vivo, during the repair of bone fractures, can provide information about the quality of the bone. To understand the variability and anisotropic behaviour of cortical bone tissue, specimens cut from three anatomic positions of pig and bovine were investigated at the same drilling speed and feed rate. Results: The experimental results showed that the drilling force does not only vary from one animal bone to another, but also vary within the same bone due to its changing microstructure. Drilling force does not give a direct indication of bone quality; therefore it has been correlated with screw pull-out force to provide a realistic estimation of the bone quality. A significantly high value of correlation (r 2 = 0.93 for pig bones and r 2 = 0.88 for bovine bones) between maximum drilling force and normalised screw pull-out strength was found. Conclusions: The results show that drilling data can be used to indicate bone quality during orthopaedic surgery.
Źródło:
Acta of Bioengineering and Biomechanics; 2017, 19, 1; 55-62
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
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:
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:
Green fibers-reinforced cement mortar with the inclusion of nano-CaCo3 and metakaolin
Autorzy:
Hamad, Ali Jihad
Sldozian, Rami Joseph
Kadhim, Ruqaya F.
Powiązania:
https://bibliotekanauki.pl/articles/38890067.pdf
Data publikacji:
2024
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
fibers reinforced cement mortar
date palm fibers
DPF
nano calcium carbonate
nano-CaCO3
metakaolin
MK
pozzolanic materials
Opis:
Over the previous few decades, there has been a noticeable increase in interest in the use of vegetable fibers and supplemental cementitious elements in mortar and concrete. The date palm frond was utilized in this study to create date palm fibers (DPF), which were then added to the cement mortar at percentages of 1%, 2%, 3%, 4%, and 5% by cement weight. There were two types of DPFs used: one type was untreated, and the other had a mechanical treatment that created holes before applying a layer of polychloroprene (neoprene) on the surface. Metakaolin (MK) and nano calcium carbonate (nano-CaCo3) were added to the cement mortar by the weight of cement. MK was replaced by 10% of the weight of cement. Besides, the nano-CaCo3 was replaced by 1%, 2%, 3%, and 4% of the weight of cement. Mechanical tests for flowability, compressive strength, and flexural strength were conducted. In addition, one MCDM methodology called VIKOR is utilized to choose the best combination out of several combinations and criteria. The results indicate that a higher DPF concentration enhances both compressive and flexural strength. The mixtures with the DPF coating and mechanical treatment give the strongest and most significant results. In addition, the flowability of cement mortar decreases when the DPF concentration increases. In addition to the high content of nano-CaCo3 in cement mortar, given the grater reading of strength, the presence of nano- CaCo3 in cement mortar reduces the disparity in result values that have a higher DPF content. The mixtures containing 4% and 5% DPF and 3% and 4% nano-CaCo3 are the optimal ones, according to the VIKOR technique.
Źródło:
Engineering Transactions; 2024, 72, 1; 39-60
0867-888X
Pojawia się w:
Engineering Transactions
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:
Involvement of ethylene synthetic inhibitors in regulating the senescence of cut carnations through membrane integrity maintenance
Autorzy:
Hassan, F.
Ali, E.
Mazrou, R.
Powiązania:
https://bibliotekanauki.pl/articles/1079037.pdf
Data publikacji:
2020
Wydawca:
Instytut Ogrodnictwa
Tematy:
cut flower
flower senescence
1-methylcyclopropene
silver nanoparticle
nitric oxide
sodium nitroprusside
vase life
membrane stability
cut carnation
Opis:
Postharvest senescence is a critical problem of carnation cut flowers, limiting their transportation and subsequent marketing chain. This study was designed to assess whether the application of 1-methylcyclopropene (1 MCP), silver nanoparticles (AgNPs), and nitric oxide (NO) released from donor sodium nitroprusside (SNP) could prolong the vase life of cut carnations through an influence on the physiological and biochemical mechanisms involved in aging process. 1-MCP was used in the concentrations of 0, 100, 200, and 300 mg·m-3; AgNPs in the concentrations of 0, 50, 100, and 150 mg·dm-3; and SNP in the concentrations of 0, 0.1, 0.2, 0.3, and 0.4 mM. All treatments significantly extended the cut flower life compared with untreated flowers, more so with 300 mg·m-3 of 1-MCP, 100 mg·dm-3 of AgNPs, or 0.3 mM of SNP. All these chemical compounds were able to considerably improve the relative water content (RWC), reduce the malondialdehyde (MDA) content and increase the membrane stability index (MSI) in petals and, therefore, maintain the membrane integrity. In addition, they decreased the activities of acetyl-CoA synthetase (ACS) and nitric oxide synthase (NOS) and, hence, depressed the production of ethylene in carnation cut flowers through downregulating the ethylene production, what prolonged the vase life. Altogether, the application of exogenous 1-MCP, AgNPs, or SNP may provide a promising avenue to improve the postharvest performance of carnation cut flowers.
Źródło:
Journal of Horticultural Research; 2020, 28, 1; 39-48
2300-5009
Pojawia się w:
Journal of Horticultural Research
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
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:
Optimization Of Protocol For Biodiesel Production Of Linseed (Linum Usitatissimum L.) Oil
Autorzy:
Ullah, F.
Bano, A.
Ali, S.
Powiązania:
https://bibliotekanauki.pl/articles/779238.pdf
Data publikacji:
2013
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
linseed
biodiesel
protocol
optimization
Opis:
Attempts were made to optimize variables affecting the yield of linseed oil biodiesel in a base catalyzed transesterification reaction. The variables studied were reaction temperature (40-70oC), catalyst (NaOH) concentration (0.1-1.5%) and reaction time (30-180 min). The conversion of linseed oil into methyl esters was confirmed through analytical methods like 1H NMR, gas chromatography (GC) and refractometer. The maximum biodiesel yield (97š1.045% w/w) was obtained at 0.5% catalyst concentration, 65oC temperature, 180 min reaction time and 6:1 molar ratio of methanol to oil. 1H NMR confirmed the practically obtained % conversion of triglycerides into methyl esters which was further evidenced by refractometer analyses. The refractive index of biodiesel samples was lower than pure linseed oil. GC analysis confirmed the presence of linolenic acid (C18:3) as the dominant fatty acid (68 wt. %) followed by oleic acid (C18:1), linoleic acid (C18:2) and stearic acid (C18:0) respectively. The physical properties of linseed oil biodiesel like specific gravity (0.90 g/cm3) and flash point (177oC) were higher than American Society for Testing and Materials standards (ASTM 6751) for biodiesel. However, kinematic viscosity (3.752 mm2/s) was in the range of ASTM standards.
Źródło:
Polish Journal of Chemical Technology; 2013, 15, 1; 74-77
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 27

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