Comparison of performance of different tool electrodes during electrical discharge machining

186-199In this work, performance of tool electrode prepared through selective laser sintering (SLS) process has been studied along with traditional copper and brass electrodes for electrical discharge machining (EDM) of AISI 1040 stainless steel. Performance measures like material removal rate (MRR), tool wear rate (TWR), radial over cut (ROC) and average surface roughness (Ra) of the machined surface have been considered. Multi-response optimization like technique for order preference through similarity to ideal solution (TOPSIS) method has been used to find out the best parametric setting of the EDM process for maximization of MRR and minimization of TWR, ROC and Ra. Scanning electron microscopic (SEM) images of the machined surface reveals that less surface crack density (SCD) has been formed on the machined surface by the use of AlSiMg RP tool electrode followed by brass and copper tool electrodes. Although MRR decreases with the use of AlSiMg tool electrode, good surface finish with less surface crack density on the machined surfaces has been observed as compared to other two tool electrodes. SEM and EDX analysis of the machined surfaces by different tool electrodes reveals presence of tool materials on the machined surfaces with increased carbon content. Therefore, it has been recommended that AlSiMg tool electrode can be conveniently adopted for finishing and semi-finishing operations

Hiv3: An Efficient Beehive Monitoring System

Beehive monitoring plays a major role in ensuring the health of beehives by checking for overpopulation or underpopulation within a hive. Beehive monitoring provides beekeepers with the opportunity to take action and save the hive before the problem becomes irreversible. Most solutions are too expensive for everyday beekeepers and lack elements of sustainability, making it impractical for small scale beekeepers. In this thesis, we propose a solution to this problem, demonstrating its sustainability and user-friendliness, which enables us to effectively reach a larger consumer market. We support these claims through the use of sustainable systems such as using a solar panel coupled with a rechargeable battery and incorporating deep-sleep capabilities into the system’s low-power embedded system (ESP32) which is connected to a camera. The ESP32 sends images to a Raspberry Pi, which performs image processing using a machine learning model and transmits the processed images to the cloud. We present a system architecture diagram describing how these systems are integrated as well as how other measures, such as security and single sign-on, are implemented to ensure the integrity of the solution. The system tests conducted in the field show that the machine learning model yields a mean average precision (MAP) score of 52.2, compared to the benchmark score of 53.7, ensuring accurate, real-time monitoring utilizing a low-power system

Investigation on electroless copper metallization on FDM built ABS parts

174-181In this work, metallization of copper on acrylonitrile-butadiene-styrene (ABS) substrate has been fabricated by fused deposition modelling (FDM) using electroless process avoiding chemicals detrimental to environment. Four acidic baths containing five weight percentages of HF, H2SO4, HNO3 and H3PO4 varying copper sulphate (CuSO4) at 10, 15 and 20 weight percentage in each bath has been used for metallization. The metallization process in each bath has continued for seventy two hours. Copper coating obtained on the substrate by the use of different baths has been evaluated for electrical resistance, thickness of copper coated layer, percentage of copper present on the coated surface and adhesion performance. Scanning electron microscopy (SEM) and energy dispersion X-ray spectroscopy (EDX) results have indicated that all the baths are quite capable of deposition of copper on ABS substrates. However, HF bath has exhibited superior coating performance as compared to other baths. The thickness of copper coated layer and percentage of copper present in the coated layer has been found to be highest by the use of HF bath with fifteen weight percentage of CuSO4

Investigation on electroless copper metallization on FDM built ABS parts

In this work, metallization of copper on acrylonitrile-butadiene-styrene (ABS) substrate has been fabricated by fused deposition modelling (FDM) using electroless process avoiding chemicals detrimental to environment. Four acidic baths containing five weight percentages of HF, H2SO4, HNO3 and H3PO4 varying copper sulphate (CuSO4) at 10, 15 and 20 weight percentage in each bath has been used for metallization. The metallization process in each bath has continued for seventy two hours. Copper coating obtained on the substrate by the use of different baths has been evaluated for electrical resistance, thickness of copper coated layer, percentage of copper present on the coated surface and adhesion performance. Scanning electron microscopy (SEM) and energy dispersion X-ray spectroscopy (EDX) results have indicated that all the baths are quite capable of deposition of copper on ABS substrates. However, HF bath has exhibited superior coating performance as compared to other baths. The thickness of copper coated layer and percentage of copper present in the coated layer has been found to be highest by the use of HF bath with fifteen weight percentage of CuSO4

Performance Assessment of Rapid Tool Electrodes During Electrical Discharge Machining of Titanium and Its Alloy

Electrical discharge machining (EDM) is a non-conventional machining process, which is widely used these days, for machining of difficult-to-machine materials or where other conventional machining processes are unable to machine the materials. In this dissertation work, possibility of potential application of tool electrodes made of copper, tungsten and boron carbide manufactured by conventional powder metallurgy (PM), microwave sintering (MWS) and spark plasma sintering (SPS) route has been explored during electrical discharge machining of titanium alloy (Ti6Al4V) work piece. In addition to usual performance measures like material removal rate and tool wear rate, surface integrity of the machined surface in terms of surface roughness, surface crack density, white layer thickness and micro-hardness on white layer has been emphasized. Effect of change of weight percentage of tungsten and boron carbide in the tool on the listed performance measures is evaluated with respect to a traditionally used solid copper tool. The experimental plan is made based on Taguchi’s orthogonal array for different tool electrode and work piece combinations so that maximum process related information can be gathered with limited number of experiments. Analysis of data gathered through extensive experimentation reveals that the tools can be made as good as normally used copper tool electrode provided that proper ratio of weight percentage of different powders is maintained in case of preparing the tool electrodes by conventional powder metallurgy route. However, compaction of the powders and sintering of the green sample during preparation of the tool are still major concerns of the tool makers. Densification of the tool plays a major role in delivering adequate performance in machining otherwise material deposition on the work piece occurs rather than machining. In case of microwave sintering, it is observed that increase in weight percentage of tungsten and boron carbide makes the tool less dense because bonding of powder elements such as tungsten and boron carbide with copper becomes difficult. Therefore, increase in weight percentage of tungsten and boron carbide in the microwave sintered tools exhibit excessive tool wear and increased surface roughness, white layer thickness and micro-hardness on the machined surface with reduced material removal rate. The microwave sintered tool is no way superior to conventional solid copper tool insofar as the performance measures considered in this dissertation work. The tool electrodes produced by spark plasma sintering process exhibit low tool wear as compared to conventional PM tool electrodes and microwave sintered tool electrodes at higher percentage of tungsten and boron carbide in tool electrodes (weight percentage of fifteen each). As far as cracks on the machined surface are concerned, more surface cracks are found with the use of solid copper electrode in comparison to composite tool electrodes produced by spark plasma sintering process with any weight percentage of tungsten and boron carbide. Therefore, it can be concluded that spark plasma sintered tool electrodes perform in a superior manner when integrity of the machined surface is emphasized. The possibility of tool electrodes composed of aluminium, silicon and manganese powders (AlSi10Mg) produced through additive manufacturing route (selective laser sintering) has been explored for potential application in electrical discharge machining of titanium and titanium alloy (Ti6Al4V). The performance of the tool produced by selective laser sintering (SLS) process is compared with conventional copper and graphite tool electrodes. It is found that higher material removal rate can be achieved with the use of graphite electrode followed by copper and AlSi10Mg SLS electrodes. Similarly, lower tool wear can be achieved by the usage of graphite electrode followed by copper and AlSi10Mg SLS electrodes. It is concluded that AlSi10Mg SLS electrode can be conveniently used if superior surface integrity (low value of surface roughness, surface crack density, white layer thickness, and micro-hardness) is desired. In this regard, AlSi10Mg SLS electrode performs well followed by copper and graphite electrode. EDX analysis of machined work surface reveals that transfer of electrode material onto the machined work piece surface occurs during machining. Presence of silicon and magnesium on the machined work surface with increased percentage of aluminium, oxygen and carbon is found in case of usage of AlSi10Mg SLS electrode. EDX analysis of machined electrode surface reveals the transfer of work piece materials like titanium, vanadium and aluminium onto the electrode surface during the machining of titanium alloy. Optimization of the process parameters is made with the use of well tested multi-objective optimization techniques such as grey relational analysis (GRA), technique for order preference through similarity to ideal solution (TOPSIS), Grey-TOPSIS, grey-TOPSIS combined with quantum behaved particle swarm optimization (QPSO), desirability based grey relational analysis combined with firefly algorithm (FA). This is to be noted that tool fabrication cost and time can be substantially reduced if the tools with complex shape is made by powder metallurgy or additive manufacturing route rather than making the tool by conventional machining processes

Structural and electronic phase transitions in Zr1.03_{1.03}Se2_{2} at high pressure

A detailed high pressure investigation is carried out using x-ray diffraction, Raman spectroscopy and low temperature resistivity measurements on hexagonal ZrSe$_{2}$ having an excess of 3 at.\% Zr. Structural studies show that the sample goes through a gradual structural transition from hexagonal to monoclinic phase, with a mixed phase in the pressure range 5.9 GPa to 14.8 GPa. Presence of a minimum in the $c/a$ ratio in the hexagonal phase and a minimum in the full width half maximum of the $A_{1g}$ mode at about the same pressure indicates an electronic phase transition. The sample shows a metallic characteristic in its low temperature resistivity data at ambient pressure, which persist till about 5.1 GPa and can be related the presence of slight excess Zr. At and above 7.3 GPa, the sample shows a metal to semiconductor transition with the opening of a very small band gap, which increases with pressure. The low temperature resistivity data show an upturn, which flattens with an increase in pressure. The phenomenological analysis of the low temperature resistivity data indicates the presence of Kondo effect in the sample, which may be due to the excess Zr

Prediction, Synthesis and Evaluation of a Synthetic Peptide as an Enzyme-Linked Immunosorbent Assay (ELISA) Candidate for Screening of Bovine Antibodies against <i>Theileria annulata</i>

Tick-borne diseases (TBDs) of livestock are endemic across various parts of tropical countries. Theileriosis is one such economically important TBD, caused by the Theileriidae family of organisms, which is transmitted by ticks. Theileria annulata, the causative agent of tropical theileriosis, contributes a significant loss to the dairy sector by causing anorexia, high fever, anemia, inflammatory changes in vital organs and icterus, thus, a loss in milk yield. Though vaccines are available, their protective efficacy is not absolute, and treatment is limited to early diagnosis of the causative agent. Routinely, microscopic identification of piroplasms in the erythrocytes (Giemsa-stained) of infected animals or schizonts in lymph node biopsies are practiced for diagnosis. PCR-based techniques (multiplex, uniplex, nested and real-time) have been reported to perform well in diagnosing active infection. Several attempts have been made using serological assays like Dot blot, ELISA and ICT, but the results were of variable sensitivity and specificity. Recombinant proteins like the Theileria annulata merozoite surface antigen (Tams1) and Theileria annulata surface protein (TaSP) have been explored as antigenic candidates for these assays. In the present study, we predicted an immunogenic peptide, i.e., TaSP-34, from the TaSP using various computational tools. The predicted peptide was custom synthesized. The diagnostic potential of the peptide was assessed by indirect plate ELISA to detect the bovine-IgM against Theileria annulata. Alongside, a recombinant truncated TaSP (rTaSP(tr)) was expressed and purified, which was used to compare the performance of the peptide as a diagnostic candidate. The IgM-based peptide ELISA was 100% sensitive and 92.77% specific as compared to PCR (Tams1 targeting), while 98.04% sensitivity and 97.44% specificity were observed in comparison with rTaSP(tr) ELISA. Almost perfect agreement between peptide ELISA and Tams1 PCR was observed with a Cohen’s kappa coefficient (κ-value) of 0.901 and agreement of 95.31%. Further, the κ-value between the peptide ELISA and rTaSP(tr) ELISA was found to be 0.95, and the agreement was 97.65%, which shows a good correlation between the two tests. The findings suggest that the TaSP-34 peptide can be an efficient and new-generation diagnostic candidate for the diagnosis of T. annulata. Furthermore, the peptide can be synthesized commercially at a larger scale and can be a cost-effective alternative for the protein-based diagnostic candidates for T. annulata.</i