Some fixed point theorems for modified JS-G-contractions and an application to integral equations

V. Srinivas Chary,G. Sudhaamsh Mohan Reddy,Huseyin Isik,Hassen Aydi,D. Srinivasa Chary,Stojan Radenovic 한국전산응용수학회 2020 Journal of applied mathematics & informatics Vol.38 No.5

In this article, we establish some fixed point results in G-metric spaces using the modified JS-G-contractions and we provide some suitable examples to support the results. Also, we give an application to solve an integral equation.

Toxic chrome removal from industrial effluents using marine algae: Modeling and optimization

A. Nagababu,D. Srinivasa Reddy,G.V. Krishna Mohan 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.114 No.-

Chromium is a toxic heavy metal with a high recalcitrant and carcinogenic nature even at very low concentrations. In the current investigation, systems thinking analysis is adopted to understand the deleteriouseffects of chromium on the environment. Hazardous chromate ions are effectively been remediatedfrom industrial discharges by employing the robust adsorbent prepared from marine algae, GracilariaRhodophyta Biochar. The combined effect of physicochemical factors such as contact time, pH, biochardosage and initial chromate concentration on adsorption performance is analyzed by adopting the statisticalResponse Surface Methodology. At the optimum operating conditions of pH: 2–4; GRB dosage:0.3 g/100 mL; contact time: 90 min; initial chromate concentration: 60 mg/L and temperature:30 C ± 2, an amount of 19.6 mg/g of chromate ions are removed by the developed adsorbent. The characterizationresults showcased the efficiency of biochar towards the adsorption of chromate ions fromwastewater. The adsorption phenomenon follows the Langmuir isotherm model and pseudo-secondorderrate kinetics. The investigation of selectivity reveals that the developed adsorbent has a good selectivityfor Cr(VI) even with the presence of competing ions in the same medium. The developed robusttechnology can be successfully applied for the adsorption of toxic chromate ions from contaminatedindustrial samples.

Structural and magnetic property studies on low temperature chemically synthesised one-dimensional Zn1−xNixO nanorods

Mohan Kumar, G.,Ilanchezhiyan, P.,Poongothai, S.,Park, Jinsub,Jayavel, R. Springer-Verlag 2014 Journal of materials science Materials in electron Vol.25 No.3

Electrical property studies on chemically processed polypyrolle/aluminum doped ZnO based hybrid heterostructures

Mohan Kumar, G.,Ilanchezhiyan, P.,Madhan Kumar, A.,Yuldashev, Sh.U.,Kang, T.W. Elsevier 2016 Chemical physics letters Vol.649 No.-

<P>A hybrid structure based on p-type polypyrolle (PPy) and n-type aluminum (Al) doped ZnO nanorods was successfully constructed. The effect of Al doping on material properties of wurtzite structured ZnO were studied using several analytical techniques. To establish the desired hybrid structure, pyrrole monomers were polymerized on hydrothermally grown Al doped ZnO nanorods by chemical polymerization. The current-voltage characteristics on the fabricated PPy/A1 doped ZnO heterostructures were found to exhibit excellent rectifying characteristics under dark and illumination conditions. The obtained results augment the prescribed architecture to be highly suitable for high-sensitivity optoelectronic applications. (C) 2016 Elsevier B.V. All rights reserved.</P>

High performance photodiodes based on chemically processed Cu doped SnS₂ nanoflakes

Mohan Kumar, G.,Xiao, Fu,Ilanchezhiyan, P.,Yuldashev, Sh.,Madhan Kumar, A.,Cho, H.D.,Lee, D.J.,Kang, T.W. Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.455 No.-

<P><B>Abstract</B></P> <P>In this work, Cu doped SnS<SUB>2</SUB> nanoflakes were synthesized through a simple hydrothermal method. The influence of Cu doping on the structural, optical and electrical properties of SnS<SUB>2</SUB> were investigated in detail. Optical properties explores the Cu doping in SnS<SUB>2</SUB> crystal lattice to result with a red-shift in absorption spectrum, which benefits visible-light absorption. Photodiodes were further fabricated by spin coating Cu doped SnS<SUB>2</SUB> nanoflakes on p-type silicon (Si). Electrical and photoelectrical parameters of Cu doped SnS<SUB>2</SUB> nanoflakes were determined by studying their impedance and current–voltage (I–V) characteristics, respectively. The diodes were found to exhibit excellent rectifying behavior and good sensitivity on par to pristine photodiodes. Impedance results identified the resistance of device to reduce considerably on Cu doping. The enhanced photoelectrical properties of the heterojunctions has been ascribed to Cu ions, which act as effective dopant and contribute to the varied carrier concentration in SnS<SUB>2</SUB>. Finally the obtained results suggest the potential of Cu-doped SnS<SUB>2</SUB> for application in photodetection and sensors applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cu doped SnS<SUB>2</SUB> nanoflakes were synthesized in hexagonal phase. </LI> <LI> Nature of charge carriers/carrier density was determined using Mott-Schottky plots. </LI> <LI> Photodiode based on Cu doped SnS<SUB>2</SUB> nanoflakes were fabricated on p-Si substrate. </LI> <LI> Photodiode revealed improved photocurrent and responsitivity values under illumination. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Evidencing enhanced charge-transfer with superior photocatalytic degradation and photoelectrochemical water splitting in Mg modified few-layered SnS₂

Mohan Kumar, G.,Cho, H.D.,Ilanchezhiyan, P.,Siva, C.,Ganesh, V.,Yuldashev, Sh.,Madhan Kumar, A.,Kang, T.W. Elsevier 2019 JOURNAL OF COLLOID AND INTERFACE SCIENCE - Vol.540 No.-

<P><B>Abstract</B></P> <P>Recently there has been immense interest in the exploration of richly available two-dimensional non-toxic layered material such as tin disulfide (SnS<SUB>2</SUB>) for potential employment in energy and environmental needs. In this regard, we report on the synthesis of few-layered Sn<SUB>1−x</SUB>Mg<SUB>x</SUB>S<SUB>2</SUB> nanosheets through a facile one-step hydrothermal route to address all such functions concerning photocatalysis and photoelectrochemical conversion. The crystalline order and structure of processed layered Sn<SUB>1−x</SUB>Mg<SUB>x</SUB>S<SUB>2</SUB> were initially found to exhibit a strong influence on their physicochemical properties. Their optical properties attest the Mg doping in SnS<SUB>2</SUB> to benefit us with enhanced visible-light absorption via red-shift in their absorption edge. In the photoluminescence spectrum the emissions observed along visible and red region signifies the association of Mg related trap states in Sn<SUB>1−x</SUB>Mg<SUB>x</SUB>S<SUB>2</SUB>. Next, the photocurrent and electrochemical impedance spectroscopic results revealed the Mg doping to promote the effective charge transfer process (which was beneficial to enhance their photocatalytic activity). Consequently, the layered Sn<SUB>0.98</SUB>Mg<SUB>0.02</SUB>S<SUB>2</SUB> made photoanodes displayed 1.7 fold higher photocurrent density under simulated solar radiation with respect to their undoped counterpart. Furthermore, the layered Sn<SUB>0.98</SUB>Mg<SUB>0.02</SUB>S<SUB>2</SUB> nanosheets exhibits enhanced visible light decomposition of organic dye while compared with pristine SnS<SUB>2</SUB> nanosheets. The value of rate constants obtained for the Sn<SUB>0.98</SUB>Mg<SUB>0.02</SUB>S<SUB>2</SUB> nanosheets was found to be 1.4 times higher than that of pristine SnS<SUB>2</SUB>. Finally, the results obtained through the present study projects the huge potential of layered Sn<SUB>0.98</SUB>Mg<SUB>0.02</SUB>S<SUB>2</SUB> nanosheets for future multifunctional applications.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Fabrication of polypyrrole/ZnO nanowires based organic–inorganic hybrid p-n junctions

Mohan Kumar, G.,Madhan Kumar, A.,Ilanchezhiyan, P.,Kang, T. W. Springer Science + Business Media 2015 Journal of materials science Materials in electron Vol.26 No.4

Mineral magnetic properties of ultisol profiles from tropical southern India

Mohan Reethu,Kizhur Sandeep,Joju G. Sebastian,Anish K. Warrier,Geetha H. Aravind,Abdul K. Rafaz,Jithin Jose,Radhakrishnan Akshay,Vadakkath V. Suhaiba 한국지질과학협의회 2023 Geosciences Journal Vol.27 No.5

The magnetic grain size, mineralogy and concentration of five ultisol sequences (lateritic soil profiles) developed on different parent rocks (syenite, dolerite, charnockite, gneiss and sandstone) in southwestern India were investigated to gain a better understanding of the pedogenic processes under tropical climate. Field investigations reveal the presence of various horizons in the lateritic profiles, such as saprolite, saprock, pallid zone, mottled zone, pebble horizon and top soil. These horizons exhibit differences in their mineral magnetic, Fourier Transform Infrared Spectroscopic (FTIR), Diffuse Reflectance Spectroscopic (redness %, amplitudes of goethite (AGt) and haematite (AHm)) and particle size properties. Magnetic susceptibility (χlf) values of the ultisol profiles varies from 5.8 to 2858.7 × 10−8m3kg−1, whereas percentage frequency dependent susceptibility (χfd %) ranges between 0.15% and 14.0%. The FTIR spectra reveal the presence of minerals like haematite, goethite, kaolinite and quartz. The upper horizons (top-soil and pebble horizon) are marked by magnetic enhancement by ultra-fine grained superparamagnetic (SP) minerals with low coercivity, most likely magnetite/maghemite. Whereas, the lower horizons (saprock, saprolite, pallid zone horizons) exhibit no magnetic enhancement and are characterized by antiferromagnetic minerals, e.g., haematite/goethite. The unweathered parent rock is characterized by low coercivity minerals of coarser magnetic grain size with a little to no superparamagnetic (SP) grains. However, the magnitude of enhancement of fine grained ferrimagnetic grains in the top soil in relation to bottom horizons varies among the five lateritic profiles. The degree of enhancement and production of the fine-grained superparamagnetic grains in topsoil decreases in the order charnockite > syenite > sandstone > gneiss > dolerite. Because the doleritic parent rock exhibits a high initial Fe concentration, it is difficult to ascertain the degree of pedogenesis, due to a strong lithogenic signature, which decreases towards the profile top. The tropical soils in the region have undergone a higher degree of pedogenesis with increased magnetic mineral concentration compared to temperate soils. However, magnetic grain size appears to be the same in both soil types. The magnetic enhancement in the topsoil may be due to the neoformation of fine-grained SP magnetite, aided by sufficient Fe supply, alternate wetting and drying cycles, dehydration, oxidation and redox conditions.

Ld(1) IS O(logloglogd) FOR ALMOST ALL SQUARE FREE d

G. S. Mohan Reddy,SS Rau 장전수학회 2020 Proceedings of the Jangjeon mathematical society Vol.23 No.3

Let d be a square free integer.Using Hardy-Ramanujan's value of nor- mal order of w(d) we show that Ld(1) = ○(logloglogd) except on a negligible set. We note that the proof verifies Robin's inequality σ(n) < eϒ nloglogn (equivalent form of Riemann Hypothesis) for such numbers.

Electrochemical studies on two-dimensional ZnInO nanoplates for organic–inorganic hybrid photodiode related applications

Mohan Kumar, G.,Madhan Kumar, A.,Ilanchezhiyan, P.,Kang, T.W. Elsevier 2015 JOURNAL OF ALLOYS AND COMPOUNDS Vol.619 No.-

<P><B>Abstract</B></P> <P>An ultra low cost route has been established to fabricate organic–inorganic hybrid <I>p</I> <I>–</I> <I>n</I> junctions <I>via</I> chemical <I>in-situ</I> polymerization of organic monomers on traditionally drop casted inorganic deposits. In this regard, ZnInO nanoplate-like structures were synthesized through a facile solution based chemical approach and their structural property was studied using X-ray diffraction patterns. The nature of charge carriers and donor density in ZnInO made electrodes were studied using electrochemical impedance spectroscopy. The dissemination of polymer matrices on the ZnInO nanoplates was examined through scanning electron microscopy. The current–voltage characteristics obtained across the polypyrrole/ZnInO made hybrid structures revealed an improved rectifying behaviour under illuminated conditions. The mechanism behind the drastic decrease in resistance values that substantiates the improved electron transfer characteristics across the organic–inorganic structures was studied through cyclic voltammetric measurements.</P>