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An optimization strategy to improve performance in electrochemical discharge machining of borosilicate glass using graph theory algorithm and desirability index
No full textElectrochemical discharge machining (ECDM) a combined version of electrical discharge machining (EDM) and electrochemical machining (ECM), is an emerging alternative method to shape low machinability material like borosilicate glass. Since the material removal rate (MRR) decreases with the machining depth due to insufficient electrolyte at the tool tip, the radial over cut (ROC) is found at the entrance due to accumulation of electrolyte. To overcome these issues, a hybrid electrolyte (HE) of NaOH+ 5% KOH is proposed in the present study, because the HE has low viscosity and high electrical conductivity compared to individual conventional electrolyte (CE). Experiments are conducted with an in-hose developed ECDM set-up integrated with metal oxide semiconductor field effect transistor (MOSFET) assisted power module. Experimental plan developed based on L9 orthogonal array with three process variables, electrolyte concentration, applied voltage, and duty factor at three levels, taper angle (TA) and ROC considered as quality characteristics and MRR is considered as performance characteristics. In this paper, a novel simultaneous multi-response optimization technique by combining Graph theory algorithm (GTA) and desirability function approach (DFA) is presented. Weights for the responses are calculated using the GTA and are used to evaluate overall (composite) desirability index (ODI) and it is treated as the multi response performance index (MRPI) to determine optimum levels for the process variables. ANOVA test indicated that DF has more influence on machining performance with 47.16% for CE and 57.06% for hybrid electrolyte. An increased MRR, and a reduction in OC and TA was noticed with HE compared to CE. In addition, SEM images revealed a smooth machined surface texture with CE and a feathery-like machined surface texture with HE. The average of the response values from the confirmation tests were found to be within the ±5% of predicted mean value, and the optimal values obtained from the proposed optimisation technique are confirmed
Synthesis of multifunctional graphene exhibiting excellent sonochemical dye removal activity, green and regioselective reduction of cinnamaldehyde
Get PDFThe present synthetic protocol focused on the green, cost-effective and bio-synthesis of multifunctional graphene by employing a highly biomedicinal plant, Kigelia Africana
stems aqueous extract as a reducing and stabilizing agent. The synthesized graphene is characterized by UV-Visible, FT-IR, XRD, Raman, HR-SEM and HR-TEM techniques. Thus synthesized grapheme sample demonstrated excellent dye removal activity by adsorbing Rhodamine B and Alizarin Red dyes, where most of the dyes are removed within 5 min by the sonochemical process. Further, the graphene established regioselective and efficient reduction of cinnamaldehyde to cinnamyl alcohol in an aqueous medium with excellent yields (94 %)
Efficiency of Antiscalants in Industrial Cooling Water Systems
No full textIn many industrial operations formation of deposits on heat exchanger surfaces and other cooling systems is a persistent problem. These deposits contain mineral scales (CaCO3, CaSO4, Ca3 (PO4)2, CaF2 etc.), corrosion products (Fe2O3, Fe3O4, Cuo etc.), particulate matter (clay, silt etc.) and microbiological mass. Deposition of these materials on heat exchange surfaces lead to loss of system efficiency, overheating, unscheduled shutdown and ultimately failure of heat exchangers. In cooling and boiler water systems, these deposits normally accumulate in low circulation areas and may become immobilized during upset conditions resulting in buildup of deposits on heat exchangers. An effective cooling water treatment must control scale, particulate matter and corrosion. Over the years, a variety of antiscaling agents have evolved including acid/chromate, zinc/chromate, stabilized phosphonate, phosphate/zinc/polymer and all organic. Phosphonates are excellent calcium carbonate inhibitors or antiscalants which reduce the scale formation in cooling water systems. Determination of efficiency of these antiscalants is also important before using them. Techniques (Boffardi, ONGC) presently used for determining their efficiency do not provide consistent results, these methods are time consuming and also difficult to execute. Industries are facing problem in finding the optimum dosage ofantiscalant in cooling water systemswith a peculiar composition. So, a technique based on the theoretical considerations has been given herein, which produces consistent results in an easy way and requires less time to perform using cooling system water
Effect on the Mechanical Properties of Grey Cast Iron with Variation of Molybdenum and AS – Cast Alloying Elements
Get PDFMetal casting is a predominant manufacturing advancement for adeptly fabricating components with complicated shapes. Many of the industrial castings produced are made from steel and iron alloys with attractive properties and less production cost. In this research work, the effect of molybdenum addition to class 30 type grey cast iron for the production of high performance cast iron (HPCI) has been carried out. Molybdenum inclusion not only refines the majority of graphite flakes but also increases the length of a small fraction of graphite flakes and improves the thermal conductivity by a percentage up to 2.2% fixed as per the research conducted, while excessive molybdenum insertion not only induces precipitation and solution reinforcement but it will also enhance the ultimate tensile strength (UTS) and hardness. According to research conducted, it was proved that molybdenum inclusion of 120 gm showed a functional way to spread HPCI with enhancing mechanical and thermal properties in grey cast iron when compared to other percentages of molybdenum used and also the average difference in the percentage of hardness in each type of molybdenum sample is about 5 to 10 %. Finally, after the tests, it was also predicted that the molybdenum’s hardenability property was beneficial for white cast iron production which will rise the wear resistance property
A computational study on boron dipyromethene ancillary acceptor-based dyes for dye-sensitized solar cells
No full textAbstract
A series of (D-π)2-An-A based organic dyes containing boron dipyrromethene (BODIPY) moiety as an ancillary acceptor (An) derivative were chosen, and the effect of donor moieties
(diarylamine, carbazole, azepine, and dibenzazepine) was investigated to understand their photophysical and photoelectrochemical properties by employing density functional theory (DFT) and time-dependent DFT. It is experimentally proved that BODIPY enhances the
light-harvesting in red and near IR region of visible light. The electron density distribution analysis was performed for all the dyes to confirm the intramolecular charge transfer,
envisioned from the simulated absorption spectra of the dyes. Carbazole donor-based dye exhibited the lowest reorganization energy. A dye attached to the TiO2 (1 0 1) surface was
modeled to estimate the adsorption energy of the dyes. The density of states analysis revealed that the absence of defect states in the bandgap of TiO2 facilitates the smooth electron
transfer from the excited state of the dye to the conduction band of TiO2. Considering the lowest unoccupied molecular orbital (LUMO) energy level of dyes and conduction band energy level of TiO2, it is understood that all the dyes studied in this study are capable of electron injection upon photoexcitation. Considering the driving force for dye regeneration of
Page 1 of 30 New Journal of Chemistry New Journal of Chemistry Accepted Manuscript Published on 20 February 2020. Downloaded on 2/26/2020 2:51:59 AM. View Article Online DOI: 10.1039/C9NJ05334D the dyes and the magnitude of reorganization energy, carbazole donor-based dye (D2) would
be the best performing dye in DSSC. Previously, the power conversion efficiencies of the dyes have been reported, and carbazole donor-based dye (D2) exhibited the highest efficiency
among all the dyes. Our computational investigations are in good agreement with the experimental results
FEA investigation of process parameters effect on machining characteristics in helical milling
No full textThe manufacturability of products depend on geometrical features and machining characteristics involved in operation like cutting forces, power consumption etc. The aim of proposed FEA study is estimating the cutting forces, power consumption and torque while helical milling AISI 4340 alloy steel, a hole making process and a unique alternate for drilling. The process parameters involved in study are spindle speed, feed and orbital speed. Simulations are performed based on L8 Taguchi DOE. The simulation outcomes are validated with artificial neural network predictions of the responses and the results
found to be agreeabl
Experimental Evaluation of AN SI Engine Using E10 Equialent Ternary Gasoline-Alchohol Blends
No full textEthanol can be used as an alternate fuel in internal combustion engines. But extensive usage of ethanol is restricted because of its biomass limit. On the other hand methanol can be obtained from different bio-resources and has the potential to
be used in engines. To limit the usage of ethanol, a model of ternary blends of Gasoline, Ethanol and Methanol (GEM) has been formulated equivalent to binary blend of Gasoline and Ethanol. The prepared ternary blends have identical Air Fuel
ratio, Lower heating value and Octane number as binary blend. In the present work the influence of GEM blends in single cylinder, four stroke, and port fuel injection SI engine in terms of performance and emission parameters have been studied
experimentally. The tests were conducted at constant engine torque of 7.5 Nm and vary the engine speeds from 1700 to 3300 rpm. The measured performance and emission values of binary blend E10 (G 90 E 10) and ternary blends E10_B1 (G
91.65 E 5 M 3.35), E10_B2 (G 92.5 E 2.5 M 5) were compared with pure gasoline, G. The results show that GEM blends have similar performance characteristics as binary blends and better compared to pure gasoline. Also exhaust emissions such as
Carbon monoxide (CO), unburned hydrocarbons (HC) shows decreased values for binary and ternary blends compared to pure gasoline due to oxygenated nature of alcohol blended fuels
Green Engineering Strategies on Solid Waste Management to Promote Urban Environmental Sustainability
No full textSolid waste is very biggest problem in the coming days of human existence as the occupancy of solid waste in all most all rural to urban areas is increasing with a rapid improvement graph without any control over it. The major reason behind this undesired occupancy is always linked up with various developmental activities such as unscientific handling of solid waste, along with urban sprawl of the cities and the areas where there is no way concern of increasing solid waste. As part of the solid waste generation with respect to its categories it is different and purely depends on its characteristic features of the generating source which can be separated as recyclable and non recyclable wastes. It is always encouragble to focus on all the possibilities to adopt recyclable materials right from the
consumption such as paper glasses, rather than plastic glasses, jute bags instead of polyethylene carry bags, etc. which can reduce the burden on solid waste with respect to safe
disposal activities. The problems associated with solid waste has been increasing especially with respect to available land for dumping majorly in the urban municipal areas because of
over occupancy of population and the quantity of generating solid waste from their daily activities is varying year by year in the name of improving living standards of the respective
area
A Study On Abrasive Water Jet Machining Using ANOVA On D3 Tool Steel
No full textThe pressurized high-speed water flows together with the Al2O3 particles forms slurry used in abrasive water jet machining (AWJM) to slice specimens. This approach is particularly appropriate for fragile, soft and strident materials. D3 tool
steel used as a sample size of 200 x 200 x 23 mm has excellent strength and is also suitable for high-temperature machining operations. In the present work, the 8 mm diameter hole was created using AWJM. The L27 orthogonal array experiments were conducted with crossover speeds (Ts) 80, 100 and 120 mm / min, abrasive mass flow rate (Af) 250, 325 and 400 (g / min) and a standoff distance (Sod) of 1,1.5 and 2 mm as processing parameters. Optimum parameters have been set from ANOVA to
achieve high metal extraction. Optimum Sod, Ts, and Af are 400 g / min, 1.5 mm and 120 mm / min. Experiment number 26 and the 27 processing parameters are the best for the D3 tool steel unit to achieve higher metal extraction
Structural and electrochemical studies of La2O3 coated LiCoO2 particles
No full textNanocrystalline LiCoO2 particles have been surface modified with La2O3 by a simple and cost effective resin coating process. The synthesized pure and La2O3 coated samples were characterized by thermogravimetric analysis / differential scanning calorimetry (TGA/DSC), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. XRD studies revealed that the presence of La2O3 coating over LiCoO2 particles did not affect the original layer structure of pure LiCoO2. Also, no extra peak was detected for La2O3 phase. FTIR results confirmed the structural co-ordination of the samples. Also, the shifting and broadening of IR peaks corresponding to LiCoO2 confirmed the presence of IR peaks of La2O3. TEM image showed the formation of interconnected small nanoparticle subunits structure for LiCoO2. TEM image also showed the presence of thin La2O3 layer over LiCoO2 particles. The cyclic voltammetry studies revealed that the La2O3 coated LiCoO2 particles exhibited reversible redox peaks with slight increase in peak intensity and peak area compared to pure LiCoO2. It indicates an improved charge storage capacity of La2O3 coated LiCoO2 sample compared to pure LiCoO2 sample