Autor: Kumar, M. A. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Mechanical & Thermal Properties of Epoxy Based Hybrid Composites Reinforced with Jute / Sansevieria cylindrica Fibres
Autorzy:: Kumar, M. A.
Reddy, G. R.
Tematy:: jute fiber
hybrid composites
mechanical properties
Sc fiber
thermal properties; Pokaż więcej
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Powiązania:: https://bibliotekanauki.pl/articles/411940.pdf Link otwiera się w nowym oknie
Opis:: Tensile properties are studied to assess the influence of fiber weight. Room temperature cured epoxy was impregnated with jute/Sc in order to evaluate the performance of hybrid composites. Jute/Sc fibers are taken in the 1:1 weight ratios to suspend on epoxy resin with different fiber lengths such as 1, 2, 3 and 4 cm. The variations of aforementioned properties on hybrid composites with different fiber lengths have been studied. Significant improvement in tensile strengths of the jute/Sc hybrid composites has been observed by the alkali treatments. Thermal properties such as TGA and DSC are studied to investigate the influence of change in fibre length on treated and untreated hybrid composites in which 4 °C rise in decomposition temperature, 3 °C rise for glass transition temperature respectively.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Biodegradable Sansevieria cylindrica Leaves fiber/ Tamarind fruit fiber based Polymer hybrid composites on characterization
Autorzy:: Reddy, G. R.
Kumar, M. A.
Jayaramudu, J.
Tematy:: hybrid composites
mechanical properties
thermal
SEM; Pokaż więcej
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Powiązania:: https://bibliotekanauki.pl/articles/411831.pdf Link otwiera się w nowym oknie
Opis:: This paper deals with the preparation and characterization of epoxy tamarind fruit (Tf) and Sansevieria cylindrica (Sc) hybrid composites containing fiber 0:20, 5:15, 10:10, 15:5 and 20:0 of (Tf:Sc) combinations loading. Sansevieria cylindrica leaves were used in this paper for extracting fiber out of it and in the similar manner ripen Tamarind fruit was used to extract fiber. Two different fibers viz. tamarind fruit/ Sansevieria cylindrica fibers were loaded into the epoxy system to develop the hybrid composites. The tensile and flexural properties of the resulting 20 wt. % loading of Tf/Sc/epoxy hybrid composites were examined. The resulting hybrid composites of 20 wt. % Tf/Sc with varying combinations exhibit the optimum improvement of mechanical properties and dielectric strength. 2 °C rise in decomposition temperature and 5 °C rise glass transition temperature were observed from the TGA and DSC thermal analysis. The fractured cross sections of flexural samples were assessed their performance as a function of fiber loading of Tf/Sc/epoxy hybrid composites by SEM analysis.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Utilization of Wallostonite/ Quasi Isotropic S2 Glass Fiber Doped in to Epoxy on Mechanical and Thermal Properties
Autorzy:: Reddy, D.M.
Rakesh, C.H.
Karthikeyan, N.
Kumar, M. A.
Nagaraju, G.
Tematy:: Epoxy
Wallostonite
S2 glass fiber
characterization
DSC
TGA; Pokaż więcej
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Powiązania:: https://bibliotekanauki.pl/articles/412223.pdf Link otwiera się w nowym oknie
Opis:: Study focused on the performance of injection moulded short Wallostonite filler and chopped glass fiber reinforced hybrid epoxy composites. Results showed that hybridization of glass fiber and Wallostonite was found to be comparable to that of epoxy glass fiber composites. Analysis of fiber length distribution in the composite and fracture surface was performed to study fiber breakage fracture mechanism. The simultaneous compounding of epoxy with two fillers was done to obtain a hybrid composite. The mechanical properties of hybrid, injection molded, chopped glass fiber/ Wallostonite/epoxy composites have been investigated by considering the effect of hybridization by these two fillers. This system is expected to have considerable mechanical properties. It has been found that the tensile, flexural, and impact properties of the filled epoxy were higher than those of unfilled epoxy. The hybrid effects of the tensile strength and modulus were studied by the rule of hybrid mixtures (RoHM) using the values of single fiber composites.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Hydrophilic Modified clay Nanocomposites: Effect of clay on Thermal and Vibrational Properties
Autorzy:: Kishore, A.
Venkatesh, D. B.
Kumar, M. A.
Ramesh, A.
Murthy, K. N.
Karthikeyan, N.
Tematy:: Hydrophilic nanoclay
Epoxy Nanocomposites
mechanical properties; Pokaż więcej
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Powiązania:: https://bibliotekanauki.pl/articles/411937.pdf Link otwiera się w nowym oknie
Opis:: Epoxy (LY-556/HY-951) system filled with modified clay (MC) was synthesized by using mechanical shear mixing with the addition of hardener as tri-ethylene-tetra-amine (TETA). The effect of the fumed silica can be negated by the application of a shear force (e.g. mixing, brushing, spraying etc), allowing the liquid to flow, level out and permit the escape of entrapped air. The reinforcement effects of MC in the epoxy polymer on thermal, mechanical and vibration properties were studied. Curing study shows that the addition MC does not show any effect in the curing behavior of epoxy polymer. Thermogravimetry analysis (TGA) shows enhanced thermal stability for epoxy with MC fillers. The epoxy with MC fillers shows considerable improvement on tensile and impact properties over pure epoxy polymer. SEM studies shows that addition of clay significantly turns the epoxy system from brittle to ductile nature was played instrumental in scaling performance. The improvement in tensile and impact properties of nanocomposites is supported with the fracture surface studies. Epoxy with MC fillers shows enhanced vibration characteristics than that of the pure epoxy polymer. FTIR studies indicated the formation of C-H bonds on the surface of the nanocomposites.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Color image encryption using singular value decomposition in discrete cosine Stockwell transform domain
Autorzy:: Vaish, A.
Kumar, M.
Tematy:: discrete cosine Stockwell transform
image encryption
singular value decomposition
mean square error
structural similarity index measurement; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/173700.pdf Link otwiera się w nowym oknie
Opis:: In this paper, an image encryption technique using singular value decomposition (SVD) and discrete cosine Stockwell transform (DCST) is proposed. The original source image is encrypted using bands of DCST along with the SVD decomposed images. The number of bands in DCST, parameters used to mask the singular values, the way of permutation used to shuffle the values of SVD transformed images and the way of arrangement of SVD matrices are used as encryption keys. It is necessary to have correct knowledge of all the keys along with their respective values, for correct decryption of encrypted images. The robustness and the quality measurement of proposed work are analyzed by comparing it with some existing works.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Parametric Optimization for Producing Semi-Solid A383 Alloy using Cooling Slope Casting Process
Autorzy:: Rao, M. S.
Khandelwal, Himandshu
Kumar, M.
Kumar, A.
Tematy:: alloy A383
semi-solid alloys
casting process
cooling
hardness
non-dendritic microstructur
stop A383
stopy półstałe
proces odlewania
chłodzenie
twardość
mikrostruktura; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Powiązania:: https://bibliotekanauki.pl/articles/27314114.pdf Link otwiera się w nowym oknie
Opis:: Cooling slope casting is a simple technique to produce semi-solid feedstock with a non-dendritic structure. The cooling slope technique depends on various parameters like slope length, slope angle, pouring temperature etc, that has been investigated in the present study. This work presents an extensive study to comprehend the combined effect of slope angle, slope length, pouring temperature, on hardness and microstructure of A383 alloy. Response Surface Methodology was adopted for design of experiments with varying process parameters i.e. slope angle between 15o to 60o, slope length between 400 to 700 mm, and pouring temperature between 560 oC to 600 oC. The response factor hardness was analysed using ANOVA to understand the effect of input parameters and their interactions. The hardness was found to be increasing with increased slope length and pouring temperature; and decreased with slope angle. The empirical relation for response with parameters were established using the regression analysis and are incorporated in an optimization model. The optimum hardness with non-dendritic structure of A383 alloy was obtained at 27o slope angle, 596.5 mm slope length and 596 oC pouring temperature. The results were successfully verified by confirmation experiment, which shows around 2% deviation from the predicted hardness (87.11 BHN).
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Memory response on generalized thermoelastic medium in context of dual phase lag thermoelasticity with non-local effect
Autorzy:: Tiwari, R.
Saeed, A. M.
Kumar, R.
Kumar, A.
Singhal, A.
Tematy:: memory dependent derivative
time-delay
kernel function
non-local
continuum theory
dual phase lags; Pokaż więcej
Wydawca:: Instytut Podstawowych Problemów Techniki PAN
Powiązania:: https://bibliotekanauki.pl/articles/38694222.pdf Link otwiera się w nowym oknie
Opis:: Theory of non-local continuum is contemporary appraised and is found to be supplementary coherent to capture the impacts of each and every point of the material at its single point. The conviction of memory dependent derivative is also newly appraised and is observed to be more intuitionistic for predicting the realistic character of the real-world obstacles. Attractiveness of the belief of a memory dependent derivative lies in its unique properties such as its significant constituents – a kernel function and time-delay are freely selected according to the requirement of a problem. The present study comprises a new meticulous thermoelastic heat conduction model for the homogeneous, isotropic, thermoelastic half space medium concerning memory effects and non-local effects. Governing equations are constructed on the basis of the newly appraised non-local generalized theory of thermoelasticity with two phase lags in the frame of a memory dependent derivative. Exact analytical solutions of the physical fields such as dimensionless temperature, displacement as well as thermal stress are evaluated by using a suitable technique of the Laplace transform. Quantitative results are determined in a time-domain for different values of time by taking the numerical inversion of the Laplace transform. Noteworthy role of the constituents of the memory dependent derivative such as kernel function as well as time-delay factor has been scrutinized on the crucial field variables of the medium through computational outcomes. Moreover, the impact of non-local parameter is examined on the variations of field quantities through the quantitative results.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Optimization of network forming agents for different types of composite propellant grain
Autorzy:: Sangtyani, R.
Kumar, A.
Gupta, M.
Tematy:: mechanical properties
diol-triol ratio
chain extender
cross linker; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358316.pdf Link otwiera się w nowym oknie
Opis:: There has been a constant endeavour to improve the mechanical properties of hydroxyterminated polybutadiene (HTPB)-based, composite solid propellants. In order to have a better understanding of the requirements, a systematic study has been conducted on the effects of varying the network forming agents on the mechanical properties of nitramine based composite propellants. Under this scheme, a series of compositions was formulated using various chain extenders [1,6-hexanediol (HD) and 1,4-butanediol (BD)] and cross linkers [1,2,6-hexanetriol (HT) and trimethylolpropane (TMP)] in different proportions. Propellant formulation experiments were conducted wherein the network forming agent composition was systematically varied to achieve the maximum possible strain capability and moderately high tensile strength, keeping the weight % of the network forming agents and other ingredients constant. The mechanical properties (% elongation, tensile strength and elastic-modulus) of the finished propellant have been plotted vs. formulation number; this can be used to select a suitable network forming agent composition for a specified grain architecture and application. Network forming agents containing 1,2,6-hexanetriol provide a high elastic-modulus (120 kg/cm2) and a high tensile strength (~12 kg/cm2), which can be used in free standing grains. Network forming agents based on 1,6-hexanediol and 1,2,6-hexanetriol (in 1:1 proportion by weight) give high elongation (~50%) and a moderately high tensile strength (~9 kg/cm2), useful for case bonded propellant grains.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Genetic Algorithm for Combined Speaker and Speech Recognition using Deep Neural Networks
Autorzy:: Kaur, G.
Srivastava, M.
Kumar, A.
Tematy:: deep neural networks
genetic algorithm
LPCC
MFCC
PLP
RASTA-PLP
speaker recognition
speech recognition; Pokaż więcej
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/958089.pdf Link otwiera się w nowym oknie
Opis:: Huge growth is observed in the speech and speaker recognition ﬁeld due to many artiﬁcial intelligence algorithms being applied. Speech is used to convey messages via the language being spoken, emotions, gender and speaker identity. Many real applications in healthcare are based upon speech and speaker recognition, e.g. a voice-controlled wheelchair helps control the chair. In this paper, we use a genetic algorithm (GA) for combined speaker and speech recognition, relying on optimized Mel Frequency Cepstral Coeﬃcient (MFCC) speech features, and classiﬁcation is performed using a Deep Neural Network (DNN). In the ﬁrst phase, feature extraction using MFCC is executed. Then, feature optimization is performed using GA. In the second phase training is conducted using DNN. Evaluation and validation of the proposed work model is done by setting a real environment, and eﬃciency is calculated on the basis of such parameters as accuracy, precision rate, recall rate, sensitivity, and speciﬁcity. Also, this paper presents an evaluation of such feature extraction methods as linear predictive coding coefficient (LPCC), perceptual linear prediction (PLP), mel frequency cepstral coefﬁcients (MFCC) and relative spectra ﬁltering (RASTA), with all of them used for combined speaker and speech recognition systems. A comparison of diﬀerent methods based on existing techniques for both clean and noisy environments is made as well.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Micro-FTIR analysis to study the change in surface chemistry after addition of collectors and their effect on coal hydrophobicity
Autorzy:: Wang, W.
Kumar, A.
Holuszko, M. E.
Mastalerz, M.
Tematy:: hydrophobicity
collectors
micro-FTIR; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110471.pdf Link otwiera się w nowym oknie
Opis:: In this study, the micro-FTIR analysis was used to investigate in-situ surface properties of coal, and was directly correlated to coal hydrophobicity, as measured by the contact angle before and after the addition of collectors, to understand their suitability for flotation. Three different collectors, diesel, pine needle oil and dodecyl trimethyl ammonium bromide (DTAB) were tested. The micro-FTIR technique provided a semi-quantitative analysis of functional groups present on the coal surface exactly where the contact angle was measured and provided a visualization of collector adsorption on specific areas of coal and associated changes in coal surface properties. This analysis could lead to a smarter way of using process design in terms of reagent selection for coal flotation to obtain a product of desired petrographic composition, which would especially be useful for coking coals. This study presents a work in progress for developing a procedure for a quick pre-selection of collectors for coal flotation based on coal surface properties.
Dostawca treści:: Biblioteka Nauki

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