Browsing by Author "V.K. Verma"

Now showing 1 - 17 of 17

1,3,4-Thiadiazoles as potential EP additives - a tribological evaluation using a four-ball test
(1995) A. Bhattacharya; T. Singh; V.K. Verma; N. Prasad
This paper reports a comparative study of the wear-reducing efficiency and extreme pressure properties of 0.5% ( w v) admixtures of paraffin oil and 2-amino-5-arylamino-1,3,4-thiadiazole additives and a commercial sulphur-phosphorus additive in a four-ball test. 2-Amino-5-p-Cl-phenylamino-1,3,4-thiadiazole additive shows excellent EP properties as is evident from the surface smoothness of SEM micrographs. The tribochemistry of the wear-scar surface has been investigated by the auger electron spectroscopy (AES) technique. © 1995.
3-(Arylimino)-5-(phenylbenzylidenehydrazido)-1,2,4-dithiazolidines: Oxidative debenzylation and cyclization of 1-(phenylbenzylideneamino)-5-aryl-2-S-benzyliso-4-thiobiurets
(1980) P.K. Srivastava; S.K. Rai; V.K. Verma
A number of 3-(arylimlno)-5-(phenylbenzylldenehydrazldo)-1,2,4-dlthlazolidines have been synthesized by the oxidative debenzylation and cyclization of the corresponding 1-(phenylbenzylldeneamlno)-5-aryl-2-S-benzyllso-4-thloblurets. The characterization of these compounds has been achieved by the direct oxidation of the corresponding 2,4-dithiobiurets and also by IR spectra. © 1980, American Chemical Society. All rights reserved.
Conformational Search and Spectroscopic Analysis of Biorelevant Molecule: 5-Chloro-2-hydroxy-N-isobutyl-3-oxo-2,3-dihydrobenzofuran-2-carboxamide
(Taylor and Francis Ltd., 2023) A.K. Vishwkarma; T. Yadav; G. Brahmachari; I. Karmakar; P. Yadav; S. Saha; C. Mahapatra; G.N. Pandey; C.S.P. Tripathi; P.K. Tripathi; V.K. Verma; A. Pathak
The present communication deals with the conformational, vibrational spectroscopic analysis and molecular docking study of an important biorelevant molecule namely 5-Chloro-2-hydroxy-N-isobutyl-3-oxo-2,3-dihydrobenzofuran-2-carboxamide. We have recorded FTIR spectrum of the target molecule in the spectral range of 4000–400 cm−1 and this has been correlated with simulated spectra of the most stable conformer. Most of the theoretical frequencies showed good agreement with experimental frequencies and a few were modified. The theoretical computations on the target molecule have been performed at well-known DFT/B3LYP level. The 6-31++G(d,p) was incorporated as a conventional basis set during the complete computations. For normal modes analysis, the potential energy distributions of the most stable conformer were calculated by Molvib program. The NBO calculations were performed to ensure stability of electronic structure and to explore intermolecular interactions. Some important thermodynamical parameters have also been investigated. The effect of aqueous media revealed that target molecule becomes slightly more stable in water phase. HOMO-LUMO gap has been computed to be 4.19 eV. © 2022 Taylor & Francis Group, LLC.
Cropping geometry and nutrient management study on winter maize {Zea mays) + potato (Solatium tuberosum) intercropping
(Indian Council of Agricultural Research, 2021) V.K. Verma; R.N. Meena; D.N. Singh; P.K. Upadhyay; Rajesh Kumar Singh; Rajiv Kumar Singh
Field experiment was conducted during rabi during 2015-16 and 2016-17 at Varanasi (UP) to study the effect of cropping geometry and nutrient management on winter maize (Zea mays L.) + potato (Solatium tuberosum L.) •intercropping.Among the crop geometry, winter maize intercropped with potato (1:1) in replacement series showed significantly higher growth parameters of maize, viz.dry matter accumulation, crop growth rate and number of green leaves per plant as compared to additive series but it was found at par when winter maize grown with potato (1:2) in replacement series.However, growth parameters of potato differed interchangeably as compared to maize in winter maize + potato intercropping system during both the years.Significantly higher grain yield of winter maize and potato were found in intercropping with 1:1 and 1:2 in additive series, respectively.Assessment of intercropping indices and economics of maize and potato proved to be better in additive series as compared to replacement series during both the years of experimentation.Amongst nutrient management, growth parameters, yield attributes and yield, intercropping indices and economics of winter maize + potato were recorded significantly higher with the application of 100% RDF + 25% N through poultry manure followed by the application of 100% RDF + 25% N through vermicompost as compared to rest of the treatments during both Uie years.Thus, it may be concluded that the maize + potato intercropping in additive series with integration of poultry manure as N source gives better yield and economics of both the crops. © 2021 Indian Council of Agricultural Research. All rights reserved.
Cyclic alkyl disulphides as tribological additives
(Leaf Coppin Publ Ltd, 2000) V.K. Verma; R. Singh; A. Bhattacharya; A.K. Tripathi
The use of sulphurized natural oils, fats, hydrocarbons, terpenes and aromatic sulphides, disulphides and polysulphides, as antiwear and extreme-pressure lubricant additives, has already been established. However, the potential of cyclic disulphides merits attention. The present paper describes the synthesis and evaluation of 0.5% solutions of certain cyclic disulphides as tribological additives, namely 3-alkylimino-5-(N-methylphenyl)amino-1,2,4-dithiazolines, in paraffin oil, on a four-ball test rig with 12.7 mm diameter steel bearing balls as test specimens. All the additives in general, and 3-propylimino-5-(N-methylphenyl)amino-1,2,4-dithiazoline in particular, exhibited remarkably good antifriction and EP activity, showing a decrease in the coefficient of friction and an appreciable increase in the load-carrying capacity of the lubricant as indicated by a higher load wear index. The wear surface topography of the used test specimen was studied using scanning electron microscopy.
Daily variation in antioxidant enzymes lipid peroxidation in thyroid and plasma level thyroxine and triiodothyronine levels of a tropical bird Perdicula asiatica during reproductively active and inactive phases
(Taylor and Francis Ltd., 2017) V.K. Verma; S.K. Yadav; C. Haldar; R.K. Tripathi
The aim of this work was to study the variations in the interference of neuroendocrine pineal gland and metabolically active thyroid gland in a tropical bird, Perdicula asiatica. Maximum pineal gland activity (pineal weight and melatonin level), minimum thyroid gland activity (weight, T3/T4 and thymidine kinase activity) along with less oxidative load (MDA level, SOD, CAT and ABTS activity) were observed during reproductively inactive phase (RIP) was observed. Further, a robust and significant rhythmicity was noted in melatonin levels during RIP and RAP, but no significant rhythmicity was noted in T4/T3 level by cosinor analysis. Overall, melatonin and thyroid circadian profile suggested that melatonin might be acting as an antioxidant molecule with time of the day effect in rescuing thyroid gland from free radical load in birds. © 2016 Informa UK Limited, trading as Taylor & Francis Group.
Effect of cultural and chemical weed management practices on yield, economics and nutrient uptake under zero-till direct seeded rice (oryza sativa l.)
(Journal of Pure and Applied Microbiology, 2016) Gaurav; S.K. Verma; R.K. Meena; V.K. Verma; R.N. Meena
An field experiment was conducted during kharif seasons of 2013-14 at Varanasi, UP to evaluate the effect of weed management practices in zero-till direct seeded rice. Results revealed that weed free treatment resulted the highest yield; however, it was not economical due to high cost of cultivation. Pre-emergence application of pendimethalin (1.0 kg ha-1) fb (followed by) early post-emergence application of bispyribac (0.025 kg ha-1) at 18 days after sowing (DAS) was recorded significantly the highest number of effective tillers, grain yield (4290 kg ha-1) and straw yield (5750 kg ha-1), biological yield, harvest index (42.71 %) and NPK uptake as compared to Sesbania co-culture + residue incorporation, Sesbania co-culture fb 2, 4-D and pretilachlor fb hand weeding at 30 DAS and it were at par with the application of pendimethalin fb hand weeding at 30 DAS and pretilachlor fb bispyribac. Application of pretilachlor fb bispyribac at 18 DAS recorded maximum net returns ( 45586) and benefit cost ratio (2.7). None of the treatment as effective as weed free with respect to reduction of density and dry weight of weeds, crop growth, yield attributes and yield, and nutrients uptake.
Effect of different row ratios on growth, yield and quality of pearlmillet and clusterbean intercropping under agri-horti system of vindyan region
(Journal of Pure and Applied Microbiology, 2016) D. Singh; R.N. Meena; Y.K. Ghilotia; A.K. Gupta; R. Meena; V.K. Verma
An experiment was conducted during kharif season of 2011-12 at Agricultural research farm of RGSC, BHU, Barkachha (Utter Pradesh). The maximum plant height, number of leaves per plant and number of tillers of pearlmillet crop was observed 205.23, 26.64 and 3.37 cm at harvest under Pearlmillet+clusterbean (6:1) intercropping system. The maximum no. of grains ear-1, ear girth (cm), ear length (cm) and weight of ear were observed as 1416.75, 10.55 cm, 23.82 cm and 24.75 g under Pearlmillet+clusterbean (6:1) intercropping. The maximum test weight 9.89 g was observed under Pearlmillet + clusterbean (6:1) in intercropping. The maximum grain yield 1554.53 kg ha-1 recorded under pearlmillet sole was significantly higher over rest of the treatments. The maximum straw yield 5104.11 kg ha-1 recorded under pearlmillet sole was significantly superior over rest of the treatments. The maximum biological yield 6658.64 kg ha-1 recorded under pearlmillet sole was significantly superior over rest of the treatments. The highest value of harvest index was recorded under Pearlmillet+clusterbean (4:1) 23.47 (%) in intercropping.
Effect of nutrient management practices on productivity and profitability of Indian mustard (Brassica juncea) under irrigated condition
(Journal of Pure and Applied Microbiology, 2015) Rajesh Kumar Singh; R.N. Meena; Y.K. Ghilotia; V.K. Verma
A field experiment was carried out during the winter (rabi) seasons of 2010-2011 and 2011-2012 at Banaras Hindu University, Varanasi, to study the effect of nutrient management practices on the productivity and profitability of Indian mustard [Brassica juncea (L.) Czernj. & Cosson] under irrigated condition. The experiment was laid out in randomized block design comprised eight treatment combinations in three replications. The study revealed that conjunctive use of Azotobacter + PSB seed treatment + 100% (N + P2O5) recorded maximum growth parameters viz. plant height, number of functional leaves, dry matter accumulation and number of branches, yield attributes viz. number of siliquae, length of siliqua, seeds/siliqua and 1000-seed weight and seed as well as stover yields remained at par with 50% (N + P2O5), Azotobacter + PSB seed treatment 75% (RDNP). The maximum gross return (‘29,680 and 43,282) and net return (‘15,717 and 25,600) were obtained with Azotobacter + PSB + 100% RDNP, however maximum output: input ratio (1.16 and 1.50) was recorded under Azotobacter + PSB + 75% RDNP. © 2015, Journal of Pure and Applied Microbiology. All rights reserved.
EFFECTS OF CROP GEOMETRY AND NUTRIENT MANAGEMENT ON NUTRIENT UPTAKE AND QUALITY PARAMETERS OF POTATO UNDER WINTER MAIZE + POTATO INTERCROPPING SYSTEM
(Bangladesh Botanical Society, 2021) V.K. Verma; R.N. Meena; Gaurav; M.K. Singh
Effects of crop geometry and nutrient management on nutrient uptake and quality parameters of potato under winter maize + potato intercropping system were studied during two consecutive years (2015-2016 and 2016-17) at BHU, Varanasi, India. Results revealed that under different crop geometry the nutrient uptake (NPK kg/ha) were obtained significantly higher with 1: 2 row ratio in additive series as compared to other row ratio due to maximum plant population. The minimum nutrient uptake (NPK kg/ha) were obtained with 1:1 row ratio in replacement series. However, quality parameters (protein and starch) did not vary significantly by different crop geometry during both the years of investigation. Amongst nutrient management, the highest nutrient uptake (NPK kg/ha) and quality parameters (protein and starch) were obtained significantly with the application of 100% RDF + 25% N through poultry manure followed by the application of 100% RDF + 25% N through vermicompost. Thus, the results suggest that 1:2 row ratio (crop geometry) in additive series with 100% RDF + 25% N through poultry manure (nutrient management) followed by 100% RDF + 25 % N through vermicompost were feasible and practicable during both the years of investigations. © 2021 Bangladesh Botanical Society. All rights reserved.
Evaluation of 2,4-dithiomalonamides as extreme pressure additives in the four-ball test
(1990) T. Singh; R. Singh; V.K. Verma
Four-ball tests using 12.7 mm diameter steel bearing balls were conducted to evaluate the load-carrying and extreme pressure properties of admixtures of paraffin oil with 1,5-diaryl-2-4-dithiomalonamides and a sulphur-phosphorus commercial additive (0.5 per cent wt/vol.). 1,5-Di-p-methoxyphenyl-2,4-dithiomalonamide exhibiting wear scar diameter and friction coefficient values of 0.58 mm and 0.058 at 100 kgf (ISL) and 2.18 mm and 0.077 at 500 kgf as compared to the values of 2.05 mm and 0.022 at 56 kgf (ISL) and 2.73 mm and 0.43 at 100 kgf for paraffin oil appeared to be most effective. The surface topography of the wear scars were examined by scanning electron microscope.
Integration of various chemical herbicide on weed management and yield of Kharif Maize (Zea mays L.)
(Journal of Pure and Applied Microbiology, 2016) Arvind Kumar; S.S. Tomar; V.K. Verma; Abhinav Kumar
A field experiment was conducted in maize during kharif season 2013 on sandy loam soil at Crop Research Centre, Chirori of Sardar Vallabhbhai Patel University of Agriculture & Technology, Meerut (U.P.), to evaluate the various integration of chemical Herbicides on weed management and yield of kharif maize (Zea mays L.). The experiment was conducted in R.B.D with three replications comprising eleven treatments of weed management (weedy, weed free, Alachlor @ 1500 and 1000 g a.i. ha-1, Atrazine @ 1000 g a.i. ha-1, Metribuzin @ 750 and 250 g a.i. ha-1, Alachlor + Metribuzin @ 750 + 375 g a.i. ha-1, Atrazine + Pendimethalin @ 750 + 500 g a.i. ha-1, Atrazine +2, 4-D @ 500 + 500 g a.i. ha-1 and Sesbania (BC) @ 20 kg ha-1 + 2, 4-D @ 500 g a.i. ha-1). The results indicated that chemical methods of weed control significantly reduced the weed population and their dry weight effectively over weedy check. The maximum number of grains cob-1, weed control efficiency, nutrient uptake by crop and highest grain yield (49.3 q ha-1) were recorded with the application of Atrazine + Pendimethalin @ 750 + 500 g a.i. ha-1 and established its superiority over rest of the herbicides. Similarly, this treatment also resulted into higher gross return, net return and B: C ratio. These values were very close to weed free treatment. The per cent increase in grains and stover yield was to the tune of 107.14 and 57.26 as compared to weedy check.
Tribochemistry and EP activity assessment of Mo-S complexes on steel balls of different compositions
(1991) T. Singh; V.K. Verma
The paraffin oil admixtures with some Mo-S complexes were evaluated as potential EP lubricant additives in the 'four-ball test' using 12.7 mm diameter steel balls of different compositions. The oil-soluble additive, bis(oxinato)-μ-oxo-μ-sulphido-dioxomolybdenum(V), was found to be quite effective against the steel balls of different compositions. The tribochemistry and topograph of the used ball specimens were examined by means of scanning auger electron spectroscopy and scanning electron microscopy respectively.
Tribological evaluation and tribochemistry of some dialkyldithiomalonamides and their Mo-S complexes as EP additives
(Leaf Coppin Publ Ltd, 2000) A.K. Tripathi; P.K. Singh; A. Bhattacharya; R. Singh; V.K. Verma
The reported use of molybdenum dithiocarbamates and molybdenum dithiophosphates as antiwear and EP additives has led to attempts by the authors to synthesize certain novel Mo-S complexes, and evaluate their effectiveness. In the present paper, the synthesis of certain 1,5-dialkyl-2,4-dithiomalonamides and their Mo-S complexes, namely, bis(1,5-dialkyl-2,4-dithiomalonamido)-dioxo-molybdenum (VI), and the tribological evaluation of their 0.5% w/v admixtures in paraffin oil by a four-ball test are reported, and the results compared with a dioxo-bis(N,N-diethyldithiocarbamato)-molybdenum(VI) reference additive. The additive, bis(1,5-diethylhexyl-2,4-dithiomalonamido) -dioxo-molybdenum(VI), has been found to reduce significantly both coefficient of friction and wear-scar values, and to give higher load wear index values and flash temperatures, and has been found to be equally effective with alloy steel balls of three different compositions. However, all the Mo-S complexes afforded smaller wear-scar diameters in a one-hour wear test. The wear spots on the used steel ball specimens were subjected to SEM and AES surface analysis for understanding the additive-metal interaction tribochemistry.
Tribological evaluation of N-phenylformamidino-N′-alkylthiocarbamides and their Mo-S complexes as EP lubricant additives
(1999) A.K. Tripathi; A. Bhattacharya; R. Singh; N. Prasad; V.K. Verma
The tribological properties of 0.5% solutions of N-phenylformamidino-N′-alkylthio-carbamides and their Mo-S complexes, i.e., μ-hydroxo-μ-(N-phenylformamidino-N′-alkylthiocarbamido)-bis- (dioxohydroxo molybdenum VI) in paraffin oil were evaluated in a four-ball test. In particular, μ-hydroxo-μ-(N-phenylformamidino-N′-ethylthiocarbamido)-bis- [dioxohydroxo molybdenum VI] was found to exhibit an appreciable increase in the load carrying capacity and values of flash temperature parameter, load wear index and pressure wear index and a decrease in the values of coefficient of friction. However, the Mo-S additives did not markedly improve anti-wear characteristics in the wear tests. A comparative EP evaluation of μ-hydroxo-μ-(N-phenylformamidino-N′-ethylthiocarbamido)-bis- (dioxohydroxo molybdenum VI) using steel balls of different compositions, indicated its suitability of replacing alloy steel balls with cheaper carbon steel balls. The topography of the wear scars on the used steel ball specimen was studied by SEM.
Tribological studies of some N, S, and Cl containing extreme pressure additives
(1994) A. Bhattacharya; T. Singh; A.P. Singh; R. Singh; V.K. Verma
The antiwear and EP properties of certain p‐chlorophenyl groups containing nitrogen and sulphur open‐chain and cyclic compounds, in paraffin oil, were evaluated in a four‐ball test. The performance of the additives were compared with a commercially available sulphur‐phosphorus reference additive. All the additives, in general, exhibited good EP activity at different loads as compared to paraffin oil and the reference additive. However, the cyclic additives, e.g., 2‐phenyl‐3‐phenylimino‐5‐p‐Cl‐phenylamino‐1,2,4‐thiadiazolidine, and 2‐amino‐5‐p‐Cl‐phenylamino‐1,3,4‐thiadiazole, were found to possess good antiwear and EP properties in comparison to the plain paraffin oil, reference additive, and open chain additives. The wear surface tribochemistry and topography were studied using Scanning Auger Electron Spectroscopy (AES) and Scanning Electron Microscopy (SEM) techniques, respectively. A comparative EP activity evaluation of 1‐p‐Cl‐phenyl‐2,5‐dithiohydrazodicarbonamide and 3‐p‐Cl‐phenylimino‐5‐(N‐methylphenyl)amino‐1,2,4‐dithiazoline on steel bearing balls of different composition was undertaken to assess the suitability of replacing chromium alloy steel balls with cheaper carbon steel balls. The additive, 3‐p‐Cl‐phenylimino‐5‐(N‐methylphenyl)amino‐1,2,4‐dithiazoline exhibited its effectiveness on the alloy steel as well as low carbon steel bearing balls. A plausible explanation for the enhanced activity of additives is suggested and efforts made to correlate the effect of substituents and structure on the efficiency. Copyright © 1994 John Wiley & Sons, Ltd
Wear reduction using some extreme pressure lubricant additives and their tribological studies
(1988) A. Mammen; C.V. Agarwal; V.K. Verma
Certain S‐containing organic compounds were synthesized and their extreme pressure (EP) properties assessed. The series of compounds studied were: S‐alkylisodithiobiurets, alkyl‐S‐alkyl xanthates, S‐alkylisothioamides, S‐benzylisothiocarbamides and 1‐formamidino‐2‐benzyliso‐3‐arylthiocarbamides. These additives were compared with a commercial additive. The tribological end effects were studied using a Scanning Electron Microscope. Some of the compounds tested were found to be effective EP additives. Wherever possible, a plausible explanation for the enhanced activity has been given, and we have attempted to correlate the effect of substituents on efficiency. Also, the effect of additives on balls of different compositions is discussed. The possibility of replacing the costly chromium steel alloy balls by less costly mild steel balls is suggested. Some of the additives developed are found to be effective on balls of certain compositions while they are a total failure on the chromium steel balls. The studies reveal that some additives are effective on mild steel balls as well as chromium alloy steel balls. They can be very good substitutes for commercial additives with bearing balls of standard composition. As chromium alloy steel balls are much costlier there is a need to replace expensive alloy steel balls with cheaper low carbon steel balls, for certain specific purposes. This can be achieved by using suitable indigenous additives that are found to be effective on low carbon steel balls. Copyright © 1988 John Wiley & Sons, Ltd