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Wyświetlanie 1-11 z 11
Tytuł:
Selective dispersion-flocculation and flotation studies on a siliceous copper ore
Autorzy:
Mweene, L.
Subramanian, S.
Powiązania:
https://bibliotekanauki.pl/articles/109546.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
flocculation
adsorption
zeta potential
dispersion
chalcopyrite flotation
Opis:
A low-grade copper ore from Mpanda Mineral Field (MMF), Tanzania containing 0.90% Cu, 10.40% Fe and 58.3% SiO2 was subjected to beneficiation adopting selective dispersion, flocculation and flotation techniques. Based on the mineralogical characterization of the sample chalcopyrite, pyrite and quartz were identified as the major minerals. The isoelectric point of MMF ore was observed to be at pH 2.7, signifying that the ore was highly siliceous. The addition of sodium trisilicate and xanthan gum shifted the zeta potential of ore to more electronegative values. Adsorption of xanthan gum on chalcopyrite and silica indicated that the maximum adsorption was at pH 2.3 for chalcopyrite and the adsorption isotherm exhibited L2 type of the Giles classification. On the contrary, no adsorption of xanthan gum on silica was observed. The ground ore was selectively dispersed and flocculated at pH 9.7 using 30 ppm of sodium trisilicate and 30 ppm of xanthan gum. The grade of CuFeS2 was improved to 19.8% after 3 desliming stages. Flotation of the flocculated portion was carried out at pH 10.30 using 30 g/t of potassium amyl xanthate and potassium ethyl xanthate (1:1) , 40 g/t of Na2S as a sulphidising agent and methyl iso-butyl carbinol (MIBC) as a frother yielding a rougher concentrate with silica and chalcopyrite grades of 8.4% and 23.5% respectively with corresponding recoveries of 4.8% and 92.8% respectively. Additionally, rougher concentrate was subjected to cleaner flotation yielding silica and chalcopyrite grades of 1.8% and 29.2 % respectively and with recoveries of 1.2% and 89.1% respectively.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 4; 1282-1291
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on the Change in Characteristics of Ring Yarn during Post Spinning and Yarn Dyeing Operations
Badanie zmian właściwości przędz pierścieniowych podczas przędzenia i barwienia
Autorzy:
Saravanan, A. R.
Subramanian, S.
Powiązania:
https://bibliotekanauki.pl/articles/231968.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
yarn abrasion
cone winding
hairiness
ring spinning
ring yarn
singeing
yarn imperfections
yarn tenacity
yarn dyeing
ścieranie przędzy
nawijanie stożka
włochatość
wirowanie pierścienia
przędza pierścieniowa
niedoskonałości przędzy
wytrzymałość przędzy
barwienie przędzy
Opis:
The origin of yarn hairiness has been attributed to the escape of fibres from the twisting action from within the spinning triangle. The protruding fibres entangle themselves due to the rubbing of yarn with parts of the machinery during post spinning operations and form thin places, thick places and neps. In this study, cotton combed yarns were produced by removing 14, 16 and 18% of the noil at the comber. These samples were dyed before and after singeing. The hairiness, imperfections and tenacity of the yarns were measured. The results revealed that an increase in comber noil causes a decrease in imperfections at the ring bobbin stage. The imperfections changed at different stages of post spinning operations and dyeing, and finally the difference was not appreciable, especially when the noil % was extracted beyond a certain level. The tenacity of yarn decreased when the ring bobbin was converted into a cone form, singed and dyed. Removal of a higher level of comber noil or singeing did not make a significant difference at the dyed yarn stage, although there was difference at the ring bobbin and cone stages.
Pochodzenie włochatości przędzy przypisuje się ucieczce włókien podczas procesu skręcania. Wystające włókna splątują się w wyniku styczności przędzy z częściami maszyn podczas operacji przędzenia i tworzą pocienienia i wzgrubienia. W pracy wytworzono przędze czesankowe, które następnie barwiono przed i po opalaniu. Zmierzono włochatość, niedoskonałości i wytrzymałość przędz. Wyniki ujawniły, że niedoskonałości przędz zmianiły się na różnych etapach operacji po przędzeniu i farbowania, a na końcu różnica nie była znacząca. Wytrzymałość przędzy zmniejszyła się, gdy cewka pierścieniowa została przekształcona w postać stożka. Usunięcie wyższego poziomu zgrubienia lub uskoki nie spowodowało istotnej różnicy w poziomie wybarwienia przędzy.
Źródło:
Fibres & Textiles in Eastern Europe; 2018, 3 (129); 35-39
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Utility of Chromobacterium violaceum SUK1a, an indigenous bacterial isolate for the bioremediation of Cr(VI)
Autorzy:
Prabhakaran, D. C.
Krishnan, S.
Ramamurthy, P. C.
Sivry, Y.
Quantin, C.
Subramanian, S.
Powiązania:
https://bibliotekanauki.pl/articles/109867.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
biosorption
bioremediation
chromium
bioreduction
Chromobacterium violaceum SUK1a
Opis:
The potential of an indigenous bacterial strain, Chromobacterium violaceum SUK1a, isolated from surface water samples collected from Sukinda Valley in Odisha, India, has been evaluated for the first time for the bioremediation of toxic hexavalent chromium (Cr(VI)) ions. The isolate was assessed for its Cr(VI) biosorption efficiency and the various parameters affecting the biosorption process were evaluated. A maximum Cr(VI) biosorption of about 50% was obtained, and the residual chromium was in the form of less toxic Cr(III). The Gibbs free energy of biosorption was determined to be -26.3 kJ/mol, suggestive of a chemisorption process. Additionally, the Cr(VI) biosorption by the isolate followed pseudo second order kinetics. FTIR spectral studies indicated that the surface functional groups present on the bacterial isolate such as, carboxyl, hydroxyl, amino, and phosphate groups were involved in the complexation of chromium ions with the bacterial cells. X-ray photoelectron spectroscopic studies on Cr(VI) interacted bacterial cells revealed an additional peak corresponding to Cr(III) in the Cr(2p) spectra. The surface charge of the bacterial cells subsequent to interaction with Cr(VI) were less negative compared to the pristine cells, which further substantiated the bioreduction of Cr(VI) to Cr(III). The bioremediation mechanism of Cr(VI) by the bacterial isolate is delineated to be governed by both biosorption and bioreduction processes under metabolism independent conditions. The results obtained indicate that the isolate can be a promising candidate for Cr(VI) bioremediation applications.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 4; 1266-1281
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Proximate composition of bio potential seaweeds from mandapam South East coast of India
Autorzy:
Gokulakrishnan, S.
Raja, K.
Sattanathan, G.
Subramanian, J.
Powiązania:
https://bibliotekanauki.pl/articles/11731.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Opis:
Proximate composition of the three green seaweeds viz., Chaetomorpha aerea, Enteromorpha intestinalis, Enteromorpha compressa one brown seaweed Dictyota dichotoma and one red seaweed Gracilaria corticata was investigated by determination of protein, carbohydrates, lipid, moisture and ash content. In the present study, the total protein was recarded upper most in E. intestinalis and bare minimum in E. compressa. The maximum carbohydrates recorded in C. aerea and minimum in G. corticata. The lipid content was acquired upper limit in E. compressa and least in C. aerea. The ash and moisture content in following of 5 different seaweeds are as follows: 7.45mg/g, 3.91mg/g were recorded in the C. aerea, 8.52mg/g, 3.42mg/g in the E. intestinalis, 8.58mg/g, 3.75mg/g in the E. compressa, 9.47mg/g, 4.23mg/g in the D. dichotoma and 6.95mg/g, 3.98mg/g in G. corticata. The proximate composition of 5 different seaweed species exhibited high nutritional value for human consumption.
Źródło:
International Letters of Natural Sciences; 2015, 45
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Screening and characterization of Fibrinolytic protease producing Bacillus circulans from mangrove sediments pitchavaram, South East Coast of India
Autorzy:
Sadeesh Kumar, R.
Rajesh, R.
Gokulakrishnan, S.
Subramanian, J.
Powiązania:
https://bibliotekanauki.pl/articles/11234.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Opis:
Regulation and production of Fibrinolytic enzymes from bacterial sources especially from Bacillus strains has taken a leading role in the medical sciences for the treatment of cardiovascular disorders as it removes thrombus or clots adding to its significant role in curing human health issues saving millions. Significant progress has been made during the last few years on the studies of fibrinolytic enzymes in identifying, cloning, purification, characterization and overproduction of these for commercialization in medical sciences and in fields like detergents development. Production of fibrinolytic enzyme from Bacillus circulans was done using Nutrient broth medium. In addition, a strong fibrinolytic enzyme was purified from the cultivation media. The purified enzyme was almost homogeneous with other species of same genus, as examined by SDS−PAGE and sephadex G-75 column chromatography. The enzyme had an optimal pH of 7-12, an optimal temperature of 50 °C, for fibrin hydrolysis. The molecular mass estimated by gel filtration was 24 to36 KDa. Further studies for characterization and structural elucidation are necessary for their medicinal applications and molecular biological characteristics.
Źródło:
International Letters of Natural Sciences; 2015, 01
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhanced IMC synthesis for tracking control of magnetic levitation system
Autorzy:
Elumalai, V. K.
Subramanian, R. G.
Reddipogu, J. S. D.
Srinivasan, S.
Agrawal, S.
Powiązania:
https://bibliotekanauki.pl/articles/140742.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
IMC
magnetic levitation
time delay
Q-parameterization
robustness
Opis:
This paper presents an enhanced internal model control (EIMC) scheme for a time-delayed second order unstable process, which is subjected to exogenous disturbance and model variations. Even though the conventional internal model control (IMC) can provide an asymptotic tracking response with desired stability margins, the major limitation of conventional IMC is that it cannot be applied for an unstable system because a small exogenous disturbance can trigger the control signal to grow unbounded. Hence, modifying the conventional IMC structure to guarantee the internal stability, we present an EIMC scheme which can offer better trade-off between setpoint tracking and disturbance rejection characteristics. To improve the load disturbance rejection characteristics and attenuate the effect of sensor noise, we solve the selection of controller gains as an H∞ optimization problem. One of the key aspects of the EIMC scheme is that the robustness of the closed loop system can be tuned via a single tuning parameter. The performance of the EIMC scheme is experimentally assessed on a magnetic levitation plant for reference tracking application. Experimental results substantiate that the EIMC scheme can effectively counteract the inherent time delay in the model and offer precise tracking, even in the presence of exogenous disturbance. Moreover, by comparing the trajectory tracking performance of EIMC with that of the proportional integral velocity (PIV) controller through cumulative power spectral density (CPSD) of the tracking error, we show that the EIMC can offer better low frequency servo response with minimal vibrations.
Źródło:
Archives of Electrical Engineering; 2018, 67, 2; 293--306
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and Characterization of Functionally Graded Al-6Cr-Y2O3 Composites
Autorzy:
Satish Kumar, T.
Krishna Kumar, K.
Shalini, S.
Subramanian, R.
Powiązania:
https://bibliotekanauki.pl/articles/353460.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Al-6Cr alloy
powder metallurgy
functionally graded materials
wear resistance
Opis:
The present investigation aims at fabricating a functionally graded Al-6Cr-Y2O3 composite and its microstructural and property characterization. Al-6Cr-alloys with varying percentage of Y2O3 (5-10 vol. %) have been used to fabricate FGM by powder metallurgy route. The samples were subsequently subjected to solution treatment at 610°C for 4h followed by artificially aged at 310°C for 4h. The microstructure, hardness and wear behavior of these FGM have been evaluated. FGM exhibited superior hardness (360 ± 5 VHN) as compared to the unprocessed composites (220 ± 5 VHN) due to the uniform dispersion of Y2O3 particles. Wear resistance of Al-6Cr-10Y2O3 FGM were compared that of with pure Al-6Cr alloy by dry abrasive wear test. Al-6Cr-10Y2O3 FGM composites were found to exhibit higher wear resistance with the minimum wear rate of 0.009 mm3/m compared to the Al-6Cr alloy wear rate 0.02 mm3/m.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 4; 1649-1655
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microplankton size structure induced by a warm-core eddy in the Western Bay of Bengal: Role of Trichodesmium abundance
Autorzy:
Chinnadurai, K.
Retnamma, J.
Nagarathinam, A.
Subramanian, P.R.
Singaram, P.
Shoba, S.
Powiązania:
https://bibliotekanauki.pl/articles/2078908.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
microplankton
size structure
biomass
Trichodesmium
sea surface temperature
wind
sea level
geostrophic current circulation
chlorophyll a
Bengal Bay
Opis:
Mesoscale warm-core eddies are common in the Bay of Bengal (BoB), and this study in the western BoB during Pre-Southwest Monsoon (April 2015) presents how a prolonged warmcore core eddy could modify the microplankton biomass and size structure. To investigate this, field sampling and laboratory analyses were augmented with satellite data sets of sea surface temperature (SST), winds, mean sea level anomaly (MSLA), geostrophic currents and chlorophyll-a. High SST with positive MSLA (≥ 20 cm) and a clockwise circulation, represented the occurrence of a large warm-core eddy in the western BoB. Time series data evidenced that it was originated in the mid of March and persistent there till early June, which in turn caused a decrease in the surface nutrients and chlorophyll-a. The abundance and biomass of microplankton were negligible in the warm-core eddy region. FlowCAM data showed a significant decrease in the autotrophic microplankton parameters in the warm-core eddy (av. 13 ± 9 ind. L−1 and 0.1 ± 0.04 μgC L−1, respectively) as compared to the surrounding locations (av. 227 ± 143 ind. L−1 and 0.8 ± 0.5 μgC L−1, respectively). Low nutrients level in the warm core eddy region favoured high abundance of needle-shaped phytoplankton cells dominated by Trichodesmium cells. As a result, the size of micro-autotrophs in the warm-core eddy was larger (av. 91,760 ± 12,902 μm3 ind.−1) than its outside (av. 50,115 ± 21,578 μm3 ind.−1). This is a deviation from our belief that the oligotrophy decreases the phytoplankton size. We showed here that the above understanding might not be infallible in warm-core eddies in the northern Indian Ocean due to its inducing effect on the Trichodesmium abundance.
Źródło:
Oceanologia; 2021, 63, 3; 283-300
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Antimicrobial Characteristics of Pulsed Laser Deposited Metal Oxides on Polypropylene Hydroentangled Nonwovens for Medical Textiles
Właściwości przeciwdrobnoustrojowe włóknin polipropylenowych pokrytych tlenkami metali stosowanych w wyrobach medycznych
Autorzy:
Ramamurthy, P.
Chellamani, K. P.
Dhurai, B.
ThankaRajan, S. P.
Subramanian, B.
Santhini, E.
Powiązania:
https://bibliotekanauki.pl/articles/949467.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
antibacterial activity
metal oxides
pulsed laser deposition
energy dispersive X-ray
EDX
polypropylene
hydroentangled nonwoven
działanie antybakteryjne
tlenki metali
polipropylen
włóknina
wyroby medyczne
Opis:
In this study, an attempt was made to investigate the antimicrobial activity on polypropylene (PP) hydroentangled nonwoven fabrics coated with transition metal oxides. After etching the nonwoven fabrics with RF plasma, nano-scale coatings of ZnO and CuO were done using the KrF excimer based pulsed laser deposition technique (PLD). Morphological and antimicrobial studies were carried out to elucidate the mechanism of antibiocidal behaviour of the coated fabrics. Results showed significant antibacterial activity of ZnO and CuO coated PP hydroentangled nonwovens with a better activity against gram positive S.aureus than gram negative E.coli. Inherently non-toxic, PP has excellent chemical resistance and the use of specialised PP fibres for hydroentangled nonwovens could offer scope in addition to metal oxide coatings; nano-scale biological materials such as enzymes and drugs could add specific functionality for their use as medical textiles.
W pracy podjęto próbę zbadania aktywności przeciwdrobnoustrojowej polipropylenowych włóknin pokrytych tlenkami metali. Przeprowadzono badania morfologiczne i przeciw- drobnoustrojowe powlekanych włóknin. Wyniki wykazały znaczną aktywność antybakteryjną włóknin pokrytych ZnO i CuO, przy czym wyższą aktywność antybakteryjną zaobserwowano wobec bakterii Gram-dodatnich (Staphylococcus ureus), niż wobec Gram-ujemnych (Escherichia coli). Stwierdzono, że zastosowanie nietoksycznego polipropylenu, który charakteryzuje się bardzo dobrą odpornością chemiczną, do wytwarzania włóknin powlekanych tlenkami metali pozwala na otrzymanie funkcjonalnych produktów medycznych.
Źródło:
Fibres & Textiles in Eastern Europe; 2017, 2 (122); 112-119
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Implications of an extensive salt water barrage on the distribution of black clam in a tropical estuarine system, Southwest coast of India
Autorzy:
Nagarathinam, A.
Retnamma, J.
Loganathan, J.
Singaram, P.
Kannampally Madam, S.M.
Jose, A.K.
Subramanian, P.R.
Powiązania:
https://bibliotekanauki.pl/articles/2078884.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
backwater
salt water
water barrage
black clam
abundance
distribution
tropical estuary
India coast
Opis:
Based on a monthly field sampling over a year in the Kochi backwaters (KBW), this study presents the larval ecology of black clam and discusses how an extensive saltwater barrage [Thannermukkom barrage (TB)] impacted the natural black clam resource distribution. Spatial variations in salinity were found minimal during the Southwest Monsoon (June—September) due to the predominance of the freshwater associated with heavy monsoonal rainfall. Conversely, significant spatial changes in salinity were evident during the Pre-Southwest Monsoon (March—May) and Post-Southwest Monsoon (October—February). Monthly sampling exercises revealed that the black clam stock in the KBW breeds throughout the year, as their larvae were found (8 indiv. m—3—494 indiv. m—3) in all the locations. This observation is the modification of the traditional belief that black clam in the KBW breeds only twice a year. Mesohaline condition (salinity 5—18) is the most conducive for peak spawning and larval production. There were two peaks of larval production in the KBW over a year, mainly associated with the prevalence of the optimum salinity conditions on different spatial scales. The closing of the TB after the Southwest Monsoon (September) causes shrinkage of the area of the oligohaline and mesohaline conditions, the most conducive environment for the peak spawning and larval production of black clam in the KBW. This study presents a clear case of how human alterations of the natural environment impact valuable biological resources, which may apply to many similar aquatic ecosystems across the globe.
Źródło:
Oceanologia; 2021, 63, 3; 343-355
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characteristics, types and causes of chest pain in an urban family practice secondary care center in South India
Autorzy:
Kumar G.S., Yeshvanth
Rajkumar Honest, Prince Christopher
Subramanian, Apoorva
Abraham, Ranjit
Teja Velaga, Saran
Pricilla, Ruby Angeline
Kirubah Vasandhi, David
Sunil, Abraham
Powiązania:
https://bibliotekanauki.pl/articles/553099.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Przyjaciół Medycyny Rodzinnej i Lekarzy Rodzinnych
Tematy:
chest pain
family practice
secondary care
India.
Źródło:
Family Medicine & Primary Care Review; 2017, 4; 377-381
1734-3402
Pojawia się w:
Family Medicine & Primary Care Review
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-11 z 11

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