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    Wyświetlanie 1-15 z 15
    Tytuł:
    Responses of grofth of ladys fingers (Abelmoschus esculentus L.) to different treatments methods of dairy wastewater
    Autorzy:
    Al-Dulaimi, R.I.
    Ismail, N.
    Ibrahim, M.H.
    Powiązania:
    https://bibliotekanauki.pl/articles/51987.pdf
    Data publikacji:
    2014
    Wydawca:
    Instytut Medycyny Wsi
    Źródło:
    Annals of Agricultural and Environmental Medicine; 2014, 21, 1
    1232-1966
    Pojawia się w:
    Annals of Agricultural and Environmental Medicine
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Preliminary statistical analysis of anthropometrics data in related to sitting posture among college students at east coast Malaysia
    Autorzy:
    Ibrahim, M.H.
    Ishak, N.F.
    Mukhtar, N.Z.
    Basir, M.H.
    Said, N.A.
    Mohamed, K.A.
    Awang, M.E.
    Powiązania:
    https://bibliotekanauki.pl/articles/24200579.pdf
    Data publikacji:
    2022
    Wydawca:
    Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
    Tematy:
    sitting posture
    anthropometric data
    human health
    pozycja siedząca
    dane antropometryczne
    zdrowie człowieka
    Opis:
    Purpose: To statistically analyse sitting posture using anthropometrics data among college students in Malaysia. Design/methodology/approach: This study was conducted among 52 college students consisting of males and females. Data were analysed using a common statistical tool which is the Statistical Package of Sosial Science (SPSS). Findings: Preliminary analysis of data indicated that there are wider differences in standard deviation of eye sitting height compared to the previous study conducted. Research limitations/implications: This study was conducted at only one higher learning institution/college located at East Cost of Malaysia. Practical implications: The larger value of standard deviation discovered as statistical analysis performed using combined data among male and female participants suggested that data should be segregated. Originality/value: Result obtained could be used as a preliminary guideline to design any related item in related to sitting posture.
    Źródło:
    Archives of Materials Science and Engineering; 2022, 116, 2; 81--85
    1897-2764
    Pojawia się w:
    Archives of Materials Science and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Removal of Cadmium using Alkaline-Treated Activated Carbon from Leucaena Leucocephala Biomass
    Autorzy:
    Ibrahim, W. M. H. W.
    Sulaiman, Nurul Syuhada
    Amini, Mohd Hazim Mohammad
    Kadir, W. R. A.
    Mohamed, Mazlan
    Ramle, Sitti Fatimah Mhd
    Bilgin, Ugur
    Rahman, Wan
    Powiązania:
    https://bibliotekanauki.pl/articles/2125550.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    activated carbon
    cadmium
    Leucaena leucocephala
    adsorption
    Opis:
    Water contamination that caused by heavy metals is a very common phenomenon in the industrial age. One of the popular way to treat metal contaminated water is by adsorption process using activated carbon as the adsorbent. This paper works on producing activated carbon by chemical means with impregnation ratios of NaOH:char (w/w) was predetermined at 1:1 (ACT1-1), 2:1 (ACT2-1) and 3:1 (ACT3-1) under activation temperature of 700°C. Considering the Leucaena leucocephala is a wildly, easy and fast grown species, with the availability throught the year, it was chosen to be used as the precursor. The properties of these activated carbons and its potential for cadmium removal from aqueus solution was analyzed. It was found that the highest surface area was recorded at 662.76 m²/g. Four parameters were studied which are contact time, the effect of pH, initial concentration of adsorbate and temperature. The equilibrium time was achieved in 40 min treatment at initial concentrations of 30 mg/l. The adsorbent exhibited good sorption potential for cadmium at pH 8.0 and equilibrium temperature of 30℃. Based on the results, this study had proved that activated carbon from Leucaena leucocephala biomass have the good potential to be used for removal of cadmium from wastewater.
    Źródło:
    Archives of Metallurgy and Materials; 2022, 67, 3; 1033--1036
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Prediction of brittle fracture propagation behaviour of hydroxyapatite (HAp) coating in artificial femoral stem component
    Autorzy:
    Sheng, C.H.
    Nagentrau, M.
    Ibrahim, N.H.
    Powiązania:
    https://bibliotekanauki.pl/articles/2201136.pdf
    Data publikacji:
    2022
    Wydawca:
    Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
    Tematy:
    hydroxyapatite (HAp)
    fracture
    stress intensity factor (SIF)
    artificial femoral stem
    hydroksyapatyt (HAp)
    złamanie
    współczynnik intensywności naprężeń
    sztuczny trzon kości udowej
    Opis:
    Purpose: This study addresses the brittle fracture propagation behaviour modelling of hydroxyapatite (HAp) coating in artificial femoral stem component. Design/methodology/approach: A simple two dimensional flat-on-flat contact configuration finite element model consisting contact pad (bone), Ti-6Al-4V substrate and HAp coating is employed in static simulation. The HAp coating is modelled as elastic layer with pre-microcrack which assumed to be initiated due to stress singularity. Findings: The study revealed that reducing coating thickness, pre-microcrack length and artificial femoral stem elastic modulus along with increasing bone elastic modulus will result in significant stress intensity factor (SIF) to promote brittle fracture propagation behaviour. Research limitations/implications: The influence of coating thickness, pre-microcrack length, bone and artificial femoral stem elastic modulus on fracture behaviour is examined under different stress ratio using J-integral analysis approach. Practical implications: The proposed finite element model can be easily accommodating different Hap coating thickness, pre-microcrack length, bone and artificial femoral stem elastic modulus to perform detailed parametric studies with minimal costly experimental works. Originality/value: Limited research focussing on brittle fracture propagation behaviour of HAp coating in artificial femoral stem component. Thus, present study analysed the influence of coating thickness, pre-microcrack length, bone and artificial femoral stem elastic modulus on stress intensity factor (SIF) of HAp coating.
    Źródło:
    Archives of Materials Science and Engineering; 2022, 113, 3; 34--41
    1897-2764
    Pojawia się w:
    Archives of Materials Science and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    BV solutions of multivalued differential equations on closed moving sets in Banach spaces
    Autorzy:
    Benabdellah, H.
    Castaing, C.
    Gamal Ibrahim, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1359656.pdf
    Data publikacji:
    1995
    Wydawca:
    Polska Akademia Nauk. Instytut Matematyczny PAN
    Opis:
    This paper is concerned with the existence of BV and right continuous solutions for some classes of multivalued differential equations on closed moving sets in Banach spaces.
    Źródło:
    Banach Center Publications; 1995, 32, 1; 53-81
    0137-6934
    Pojawia się w:
    Banach Center Publications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    In vitro culture of big-sage (Lantana camara L.) plant
    Autorzy:
    Ibrahim, M.A.
    Sabty, M.Z.
    Mussa, S.H.
    Powiązania:
    https://bibliotekanauki.pl/articles/12710538.pdf
    Data publikacji:
    2020
    Wydawca:
    Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
    Opis:
    The study was conducted to mass micropropagation of big sage (Lantana camara L.) plant by shoot multiplication technique. The treatments 2.22 and 2.66 µmol·L⁻¹ BA gave the highest significant increase in the percentage of response to shoot multiplication and number of shoots per explant compared to the other treatments as reached 96.70% and 100.00% and 4.33 and 6.00 shoots, respectively. The results showed that these two treatments did not differ significantly between them. While the 1.33 µmol·L⁻¹ BA gave the lowest values in the percentage of response to shoot multiplication and number of shoots per explant were 80.00% and 2.00 shoots per explant, respectively. The MS medium supplemented with 4.30 or 5.37 µmol·L⁻¹ NAA gave a high response to root formation, number of roots per shoot and root length. While the MS medium supplemented with 6.44 or 7.52 µmol·L⁻¹ NAA gave low values in these characteristics. The MS medium with 2.22 or 2.66 µmol·L⁻¹ concentration of BA or 7.52 µmol·L⁻¹ concentration of NAA recorded the highest significant increase in the percentage of response to callus formation. While the MS medium supplemented with 1.33 µmol·L⁻¹ BA or 4.30 µmol·L⁻¹ NAA gave less response to the callus formation.
    Źródło:
    Acta Scientiarum Polonorum. Hortorum Cultus; 2020, 19, 2; 67-73
    1644-0692
    Pojawia się w:
    Acta Scientiarum Polonorum. Hortorum Cultus
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A performance analysis of a hybrid golden section search methodology and a nature-inspired algorithm for MPPT in a solar PV system
    Autorzy:
    Mostafa, Hazem H.
    Ibrahim, Amr M.
    Anis, Wagdi R.
    Powiązania:
    https://bibliotekanauki.pl/articles/141645.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    hybrid optimization
    golden sections search
    multi-verse optimization algorithm
    maximum power point tracking
    perturb and observe
    photovoltaic (PV)
    Opis:
    This research presents a comparative study for maximum power point tracking (MPPT) methodologies for a photovoltaic (PV) system. A novel hybrid algorithm golden section search assisted perturb and observe (GSS-PO) is proposed to solve the problems of the conventional PO (CPO). The aim of this new methodology is to boost the efficiency of the CPO. The new algorithm has a very low convergence time and a very high efficiency. GSS-PO is compared with the intelligent nature-inspired multi-verse optimization (MVO) algorithm by a simulation validation. The simulation study reveals that the novel GSS- PO outperforms MVO under uniform irradiance conditions and under a sudden change in irradiance.
    Źródło:
    Archives of Electrical Engineering; 2019, 68, 3; 611-627
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Framework of performance measurement practices within construction companies in Egypt
    Autorzy:
    Dziekoński, K.
    Ibrahim, O. H. M. F.
    Mahamadu, A.-M.
    Manu, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/125609.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
    Tematy:
    performance
    measurement system
    construction
    industry
    Egypt
    wydajność
    system miar
    budowa
    przemysł
    Egipt
    Opis:
    The construction industry is considered as one of the most important sectors in Egypt. One of the major challenges faced by the industry, however, is the unavailability of suitable performance measurement systems for assessing companies’ performance. Modern performance assessment systems adopt a more universal approach to the measurement of construction company performance as opposed to the traditional project triangle. This paper aims to examine the practice of performance measurement in the Egyptian construction industry. Results show dominant role of in-house developed performance management systems as well as the use of KPIs as a method of performance assessment. The study further reveals that the highest importance is given to measures related to the time of project delivery, quality of works, clients’ satisfaction and profitability. Hence, the traditional project triangle of project’s success is the most prevalent approach to performance evaluation in the construction industry in Egypt. However, a shift towards a more holistic approach to performance assessment in larger companies was observed.
    Źródło:
    Engineering Management in Production and Services; 2018, 10, 2; 7-14
    2543-6597
    2543-912X
    Pojawia się w:
    Engineering Management in Production and Services
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthesis and properties of vinylpyrrolidone/ (trimethoxysilyl)propyl methacrylate gels containing different amounts of crosslinking agent
    Synteza i właściwości żelu N-winylopirolidon/metakrylan3-(trimetoksysililo)propylu z różną zawartością czynnika sieciującego
    Autorzy:
    Mohammed, A. H.
    Ahmad, M. B.
    Ibrahim, N. A.
    Zainuddin, N.
    Powiązania:
    https://bibliotekanauki.pl/articles/947044.pdf
    Data publikacji:
    2018
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
    Tematy:
    high conversion copolymers
    swelling parameters
    mechanical properties
    oxygen permeability
    crosslinking density
    kopolimery o wysokim stopniu konwersji
    parametry pęcznienia
    właściwości mechaniczne
    przepuszczalność tlenu
    gęstość sieciowania
    Opis:
    High conversion copolymers containing 90 wt % of N-vinylpyrrolidone (NVP) and 10 wt % of 3-(trimethoxysilyl)propyl methacrylate (TMSPM) with 0, 1, 2, 3 and 4 wt % (in conversion to mass of NVP/TMSPM) of ethylene glycol dimethacrylate (EGDMA) as crosslinker have been successfully synthesized. Proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared spectroscopy (FT-IR) were employed to characterize the resulting copolymers. The effect of EGDMA amount on the mechanical and thermal properties, swelling parameters, clarity, and oxygen permeability of the prepared xerogels and hydrogels were studied. 3 wt % of EGDMA is required to obtain clear xerogels and hydrogels. The water content (EWC), volume fraction of polymer (φ2) and weight loss during swelling decrease with increasing EGDMA content. Young’s and shear modulus (E and G) increase as EGDMA content increases, the values of E and G are 0.570–3.531 MPa and 0.217–1.359 MPa, respectively. The hydrogels were characterized in terms of modulus crosslinking density (ve and vt) and polymer-solvent interaction parameters (χ). The results are 0.220–0.613 mol/dm3 for ve, 0.105–0.441 mol/dm3 for vt, and 0.595–0.822 for χ. Thermal properties enhance by adding EGDMA whereas the oxygen permeability (P) of hydrogels decreases from 48.6 to 44.3 as water content decrease from 70.3 to 55.1.
    Kopolimery zawierające 90 % mas. N-winylopirolidonu (NVP) i 10 % masmetakrylanu 3-(trimetoksysililo)propylu (TMSPM) z udziałem 0, 1, 2, 3 i 4 % mas. (w przeliczeniu na masę NVP/TMSPM) dimetakrylanu glikolu etylenowego (EGDMA) jako środka sieciującego zsyntetyzowano z wysokim stopniem konwersji. Otrzymane kopolimery charakteryzowano metodami protonowego rezonansu jądrowego (H1 NMR) i spektroskopii w podczerwieni (FT-IR). Badano wpływ udziału środka sieciującego na właściwości mechaniczne i termiczne, parametry pęcznienia, klarowność i przepuszczalność tlenu wytworzonych hydro- i kserożeli. Stwierdzono, że dodatek już 3 % mas. EGDMA wystarcza do uzyskania klarownego żelu, a w miarę zwiększania zawartości EGDMA zmniejsza się zawartość wody (EWC), ułamek objętości polimeru (φ2) oraz strata masy w procesie pęcznienia żelu NVP/TMSPM. Wartość modułu zarówno Younga (E), jak i ścinania (G) zwiększa się (E = 0,570–3,531 MPa, G = 0,217–1,359 MPa) wraz ze wzrostem udziału EGDMA w kompozycji. Wytworzone hydrożele charakteryzowano za pomocą modułów gęstości sieciowania (ve = 0,220–0,613 mol/dm3, vt = 0,105–0,441 mol/dm3) i parametru oddziaływania polimer-rozpuszczalnik (χ = 0,595–0,822). Właściwości termiczne otrzymanych hydrożeli zawierających EGDMA poprawiły się wraz ze zmniejszeniem zawartości wody (70,3–55,1), natomiast przepuszczalność tlenu się pogorszyła (P = 48,6–44,3).
    Źródło:
    Polimery; 2018, 63, 9; 577-585
    0032-2725
    Pojawia się w:
    Polimery
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthesis and monomer reactivity ratios of acrylamide with 3-(trimethoxysilyl)propyl methacrylate and tris(methoxyethoxy)vinylsilane copolymers
    Współczynniki reaktywności monomerów w syntezie kopolimerów akryloamidu, metakrylanu 3-(trimetoksysililo)propylu i tris(metoksyetoksy)-winylosilanu
    Autorzy:
    Mohammed, A. H.
    Ahmad, M. B.
    Ibrahim, N. A.
    Zainuddin, N.
    Powiązania:
    https://bibliotekanauki.pl/articles/947173.pdf
    Data publikacji:
    2016
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
    Tematy:
    vinylsilane monomers
    acrylamide
    reactivity ratios
    sequence distribution
    sekwencja monomerów
    Opis:
    Copolymers of acrylamide (AM) with 3-(trimethoxysilyl)propyl methacrylate (TMSPMA) and tris(methoxyethoxy)vinylsilane (TMEVS) with different compositions were synthesized at low conversion by free radical polymerization in dimethylformamide (DMF) using benzoyl peroxide (BPO) as an initiator. The copolymers were characterized by Fourier transform infrared spectroscopy (FT-IR), and their thermal properties were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The copolymers composition was determined by elemental analysis. The monomer reactivity ratios were estimated by linearization methods proposed by Fineman-Ross and Kelen-Tudos, the intersection method proposed by Mayo-Lewis and nonlinear method proposed by curve fitting procedure. The derived reactivity ratios (r1, r2) are: 1.87, 0.80 for TMSPMA-co-AM and 0.22, 1.21 for TMEVS-co-AM. Both copolymers formed blocks of one of the monomer units. The microstructure of copolymers and sequence distribution of monomers in the copolymers were calculated by statistical method based on the average reactivity ratios and found that these values are in agreement with the derived reactivity ratios.
    Kopolimery akryloamidu (AM) z metakrylanem 3-(trimetoksysililo)propylu (TMSPMA) itris(metoksyetoksy)winylosilanem (TMEVS), o różnych składach, zsyntetyzowano w warunkach małej konwersji metodą wolnorodnikowej polimeryzacji w dimetyloformamidzie (DMF), z zastosowaniem nadtlenku benzoilu (BPO) jako inicjatora. Otrzymane kopolimery charakteryzowano za pomocą spektroskopii w podczerwieni z transformacją Fouriera (FT-IR), różnicowej kalorymetrii skaningowej (DSC) oraz analizy termograwimetrycznej (TGA). Skład kopolimerów ustalono metodą analizy elementarnej. Współczynniki reaktywności monomerów oszacowano metodami linearyzacji zaproponowanymi przez: Finemana-Rossa, Kelena-Tudosa, Mayo-Lewisa i metodą nieliniową z zastosowaniem procedury dopasowania krzywej. Otrzymane współczynniki reaktywności (r1, r2) wynosiły: 1,87 i 0,80 dla TMSPMA-co-AM oraz 1,21 i 0,22 dla TMEVS-co-AM. Oba kopolimery miały budowę złożoną zbloków utworzonych z jednostek monomerów składowych. Mikrostrukturę oraz sekwencję monomerów w kopolimerach wyznaczono metodą statystyczną na podstawie średnich współczynników reaktywności. Stwierdzono zgodność obliczeń z wartościami otrzymanymi doświadczalnie.
    Źródło:
    Polimery; 2016, 61, 11-12; 758-765
    0032-2725
    Pojawia się w:
    Polimery
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Formulating delamination-fretting wear failure predictive equation in HAp coated hip arthroplasty using multiple linear regression model
    Autorzy:
    Nagentrau, M.
    Ibrahim, N.H.
    Jamian, S.
    Mohd Tobi, A.L.
    Powiązania:
    https://bibliotekanauki.pl/articles/24200558.pdf
    Data publikacji:
    2022
    Wydawca:
    Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
    Tematy:
    hip arthroplasty
    delamination
    fretting
    HAp
    regression
    artroplastyka stawu biodrowego
    rozwarstwienie
    regresja
    Opis:
    Purpose: Present paper addresses the formulation of delamination-fretting wear failure predictive equation in HAp-Ti-6Al-4V interface of hip arthroplasty femoral stem component using multiple linear regression model. Design/methodology/approach: A finite element computational model utilising adaptive meshing algorithm via ABAQUS/Standard user subroutine UMESHMOTION is developed. The developed FE model is employed to examine effect of different HAp-Ti-6Al-4V interface mechanical and tribological properties on delamination-fretting wear behaviour. The FE result is utilised to formulate predictive equations for different stress ratio conditions using multiple linear regression analysis. Findings: Delamination-fretting wear predictive equations are successfully formulated with significant goodness of fit and reliability as a fast failure prediction tool in HAp coated hip arthroplasty. The robustness of predictive equations is validated as good agreement is noted with actual delamination-fretting wear results. Research limitations/implications: The influence of different mechanical and tribological properties such as delamination length, normal loading, fatigue loading, bone elastic modulus and cycle number under different stress ratio on delamination-fretting wear failure is analysed to formulate failure predictive equations. Practical implications: The formulated predictive equation can serve as a fast delamination-fretting wear failure prediction tool in hip arthroplasty femoral stem component. Originality/value: Limited attempt is done to explore the potential of utilizing multiple linear regression model to predict failures in hip arthroplasty. Thus, present study attempt to formulate delamination-fretting wear failure predictive equation in HAp -Ti-6Al-4V interface of hip arthroplasty femoral stem component using multiple linear regression model.
    Źródło:
    Archives of Materials Science and Engineering; 2022, 115, 2; 76--85
    1897-2764
    Pojawia się w:
    Archives of Materials Science and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effectiveness factor of two-dimensional ring-shaped catalyst pellets
    Autorzy:
    Asif, M.
    Ibrahim, A. A.
    Mohammed, Y. A.
    Al-Ghurabi, E. H.
    Powiązania:
    https://bibliotekanauki.pl/articles/780040.pdf
    Data publikacji:
    2017
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    hollow catalyst pellet
    effectiveness factor
    Thiele modulus
    convergence behavior
    analytical solution
    Opis:
    The use of hollow catalytic support improves the utilization of the catalytic material because of the absence of the pellet core, and moreover ensures low reactor pressure drop owing to enhanced bed voidage. In this study, the expressions for the efficient computation of the effectiveness factor are derived for a ring-shaped catalyst pellet undergoing first-order irreversible reaction. The methodology consists of using solutions of one-dimensional problems to remove non-homogeneous boundary conditions. The expressions obtained exhibit significantly faster convergence behavior than those reported in literature. The shape parameters, namely, the height-to-diameter ratio and the inner-to-outer radii ratio, significantly affect the catalyst utilization, such that several-fold improvement in the effectiveness factor is achievable.
    Źródło:
    Polish Journal of Chemical Technology; 2017, 19, 3; 99-105
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Minerals content, essential oils composition and physicochemical properties of Citrus jambhiri Lush. (Rough Lemon) from the Sudan
    Autorzy:
    Mohammed, A. M. H.
    Ibrahim, M. A
    Omran, A. A.
    Mohamed, E. M.
    Elsheikh, S. E. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/412508.pdf
    Data publikacji:
    2013
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Citrus jambhiri
    Rutaceae
    atomic absorption spectroscopy (AAS)
    Flame Atomic Emission Spectroscopy (FAES)
    metal content
    essential oils
    Opis:
    Minerals content of Citrus jambhiri (rough lemon) fruit was qualitatively and quantitatively analyzed using atomic absorption spectroscopy (AAS) and flame atomic emission spectrometry (FAES). The peel, moisture and ash contents of rough lemon were found to be 18.35 %, 23.75 % and 2.04 % respectively. Vitamin C (ascorbic acid) of rough lemon juice was found to be 70.0 mg/100 g. The chemical composition of essential oil of rough lemon peel was determined. The major compound was found to be limonene (84.5 %) followed by sabinene, β-myrcene, α-terpineol, 1,3-tetradecadiene and linalool.
    Źródło:
    International Letters of Chemistry, Physics and Astronomy; 2013, 9, 1; 25-30
    2299-3843
    Pojawia się w:
    International Letters of Chemistry, Physics and Astronomy
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthesis, characterization and thermal polymerization of new 3,4-dihydro-2H-1,3-naphthoxazine monomers
    Synteza, charakterystyka i polimeryzacja termiczna nowych monomerów 3,4-dihydro-2H-1,3-naftoksazynowych
    Autorzy:
    Gabbas, A. U. G.
    Ahmad, M. B. H.
    Zainuddin, N.
    Ibrahim, N. A.
    Powiązania:
    https://bibliotekanauki.pl/articles/946991.pdf
    Data publikacji:
    2017
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
    Tematy:
    1,3-naphthoxazine
    polynaphthoxazine
    thermal polymerization
    thermal properties
    1,3-naftoksazyna
    polinaftoksazyna
    polimeryzacja termiczna
    właściwości termiczne
    Opis:
    Two new 1,3-naphthoxazine monomers (M-A and M-B) were synthesized via a modified stepwise procedure in which methylene bromide was used for the ring-closure reaction. Condensation of 2-hydroxy-1-naphthaldehyde with 1,6-hexamethylenediamine or 1,4-phenylenediamine gives imine compounds, which were converted to 2-hydroxynaphthylamines by reduction with NaBH4 in methanol. Ring-closure reaction between the 2-hydroxynaphthylamines and methylene bromide results in the formation of 1,3-naphthoxazine monomers M-A or M-B with good yields. The structures of the synthesized monomers were confirmed using different spectroscopic techniques (including FT-IR, 1H NMR and 13C NMR), mass spectrometry, and elemental analysis. Thermal polymerization of the monomers was investigated by FT-IR and differential scanning calorimetry (DSC). Both the 1,3-naphthoxazine monomers undergo ring-opening polymerization, leading to the formation of the corresponding polynaphthoxazines [P(M-A) and P(M-B)]. The thermal stability of the polynaphthoxazines was thereafter studied by thermogravimetric analysis (TGA).
    Za pomocą zmodyfikowanej trójetapowej syntezy, w której do reakcji zamknięcia pierścienia zastosowano bromek metylenu, otrzymano dwa nowe monomery 1,3-naftoksazyny (M-A i M-B). Kondensacja 2-hydroksy-1-naftaldehydu z 1,6-heksametylenodiaminą lub 1,4-fenylenodiaminą pozwala na wytworzenie związków iminowych, które następnie przez redukcję NaBH4 w metanolu są przekształcane w 2-hydroksynaftylaminy. Reakcja zamknięcia pierścienia pomiędzy 2-hydroksynaftylaminą i bromkiem metylenu prowadzi do utworzenia z dobrymi wydajnościami monomerów 1,3-naftoksazyny M-A i M-B. Struktury zsyntetyzowanych monomerów potwierdzono stosując różne techniki spektroskopowe, spektroskopię masową oraz analizę elementarną. Polimeryzację termiczną monomerów badano za pomącą spektroskopii w podczerwieni z transformatą Fouriera (FT-IR) i różnicowej kalorymetrii skaningowej (DSC). Oba monomery 1,3-naftoksazyny uległy polimeryzacji z otwarciem pierścienia dając odpowiednie polinaftoksazyny [P(M-A) i P(M-B)]. Za pomocą analizy termograwimetrycznej (TGA) zbadano stabilność termiczną otrzymanych polinaftoksazyn.
    Źródło:
    Polimery; 2017, 62, 2; 86-92
    0032-2725
    Pojawia się w:
    Polimery
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Extraction of Tannic Acid from Kenaf Bast Fibre using Ultrasonic Assisted Extraction
    Autorzy:
    Mohamad, Mardawani
    Ibrahim, H. A.
    Nasir, M. F. M.
    Mohidem, Nur Atikah
    Shoparwe, N. F.
    Teo, Pao Ter
    Masri, Mohamad Najmi
    Irfan, Abd Rahim
    Powiązania:
    https://bibliotekanauki.pl/articles/2134102.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    ultrasonic assisted extraction
    UAE
    sonication time
    duty cycle
    extraction process
    kenaf bast fibre
    Opis:
    Tannic acid or tannin, type of phenolic compound contains in kenaf bast fibre. Conventional extraction has certain limitations in terms of time, energy, and solvent consumption. Ultrasound assisted extraction (UAE) can extract bioactive components in shorter time, low temperature, with lesser energy and solvent requirement. UAE as alternative extraction technique is better equipped to retain the functionality of the bioactive compounds. In this study, the conditions for ultrasound assisted extraction (UAE) of tannic acid from kenaf bast fibre by assessing the effect of sonication time and different duty cycles were optimized. The use of ultrasound to extract tannic acid from kenaf bast fiber was evaluated. Ultrasound-assisted extraction (UAE) was carried out using ethanol as solvent to intensify the extraction efficacy. Phytochemical screening was conducted to identify the presence of tannic acid in extracts. The extracts then were analyzed using High-Performance Liquid Chromatography (HPLC) and Scanning Electron Microscopy (SEM). It was found that 0.2429 mg/mL of tannic acid was obtained under the extraction conditions of extraction temperature of 40℃, sonication time of 20 minutes and duty cycle of 50%. From SEM analysis, it was found that the raw sample demonstrated rough surface and no porous but kenaf bast fibre display smoother surface with less impurities and few pores appeared after the extraction process using UAE. These results indicate that ultrasound-assisted extraction is an efficient method for extracting tannic acid from kenaf bast fibre with the advantages of lower extraction time and higher extraction yield.
    Źródło:
    Archives of Metallurgy and Materials; 2022, 67, 3; 1061--1066
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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