NUST Institutions Library Catalogue Search for 'an:"122313"'

EMG Signal Evaluation by Graph Signal Processing & Total Variation Denoising /

By Duaa, Iqra . . 63p. , Electromyography (EMG) serves as a vital diagnostic tool in medical and clinical research, enabling the monitoring and analysis of muscle electrical activity. In medical diagnostics, EMG aids in identifying and assessing neuromuscular syndromes, i.e. amyotrophic lateral sclerosis (ALS). However, EMG signals are prone to various forms of noise and interference, posing challenges to accurate data interpretation. Thus, the development of robust denoising techniques is crucial for enhancing EMG signal quality and addressing practical challenges in clinical diagnostics, rehabilitation, and neuromuscular research. This research introduces an innovative methodology integrating Variational Mode Decomposition (VMD) and Graph Signal Processing (GSP) to improve EMG signal quality. Unlike conventional approaches like Continuous Wavelet Transform (CWT), this study explores the untapped potential of VMD with Intrinsic Mode Functions (IMFs) 16 and GSP in EMG signal analysis. sEMG data collected from 10 subjects using the EMGUSB (OT Bioelettronica) underwent denoising techniques, specifically CWT, VMD, and GSP. Evaluation of noise reduction performance reveals compelling results, with GSP demonstrating superior noise reduction capabilities compared to VMD and CWT. Specifically, GSP increases the SNR by 259.15 meanwhile decreases the RMSE by 0.07. In comparison, VMD upturns SNR with 111.56 and declines RMSE of 0.15. While both VMD and GSP outperform CWT, which exhibits SNR enhancements of 90.46 and RMSE reductions by 0.15. Statistical analysis validates the significant improvements (p < 0.05) provided by VMD and GSP over CWT across varying noise levels. Notably, VMD and GSP collectively exhibit substantial enhancements in both SNR and RMSE metrics, underscoring their efficacy in preserving signal fidelity while minimizing noise and artifacts. 30cm.

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Tribological Analysis of Trihexyltetradecylphosphonium bis(2,4,4-trimethyl pentyl)phosphinate ionic liquid based Bio-Lubricants at variable operating conditions. /

By Haider , Nouman . . 72p. , All mechanical systems require lubrication between interacting surfaces to avoid failure of mechanical components and to decrease the losses due to friction, especially for the interacting bodies that operate in boundary lubrication regimes. Due to the decrease in the reserve of mineral oils, increasing environmental concerns, and difficulties in the disposal of non-biodegradable conventional lubricants, a trend is increasing amongst researchers to produce more environmental friendly lubricants. The use of bio-lubricants as an alternative to mineral based oil is limited due to its low thermal stability. Ionic liquid are molten salts which are environment friendly and can be used as additive to bio-lubricants to enhance its physiochemical properties. The effectiveness of ionic liquid in bio-lubricants depends upon a lot of factor amongst which its miscibility with that particular lubricant plays an important role. Ionic liquids make strong interaction with polar lubricants and hence can be effectively used as additives to bio-lubricants. Among ionic liquids phosphonium based ionic liquids are found to show best results with lubricants and hence is used in this study. In this thesis tribological performance of phosphonium-based ionic liquid Tri hexyl tetra decylphosphonium bis (2, 4, 4-trimethylpentyl) phosphonate when used as an additive to Cottonseed oil, Rattan Jot oil, Waste Cooking oil and Polyalphaolefin (PAO) will be studied at different operating conditions and results will be compared with conventional PAO base oil. The physical properties of these oils were already investigated by a previous student Tehreem Naveed[1] and their tribological analysis is done in this study. Tribological performance of all lubricants were studied using a four ball tribometer and its wear scars were determined using an electronic microscope OLYMPUS. From this study it was found that with the addition of ionic liquid, tribological performance of all bio-lubricants enhanced. Ionic liquid does not have much effect on the tribological performance of PAO. Rattan Jot oil was found to have the best tribological properties with and without addition of ionic liquid into it. 30cm.

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Production and Tribological Analysis of Cottonseed-based Bio-lubricant /

By Khan ,Muhammad Bilal. . 52p. ; 30cm..

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Synthesis and Tribological Analysis of Ionic Liquid-Based Bio-Lubricants /

By Naveed, Tahreem . . 56p. , Purpose. Lubrication is inevitable for all interacting surfaces in IC engines to avoid component failure and reduce frictional losses specifically operating under boundary lubrication regime. Environmental concerns, decreasing mineral oil reserves and difficult disposal of nonbiodegradable conventional lubricants have urged the researchers to shift towards environmental-friendly lubricants. In this article compatibility of various ionic liquids with different bio-lubricants and conventional lubricants regarding their tribological performance has been studied and compared. Methodology. In this study two potassium based ionic liquids including Bis(2-ethylhexyl) phosphate and Trihexyltetradecylphosphonium bis(2,4,4- trimethylpentyl) phosphinate have been checked for their compatibility towards bio-lubricants including Cotton seed oil, Waste cooking oil, Rattan Jot oil and polyalphaolefin (PAO) etc. The physicochemical properties including viscosity, density, viscosity index, kinematic viscosity, flash point, pour point, total acid number (TAN) and total base number (TBN) of bare oils and their blends with ionic liquids were investigated using different ASTM standards Findings. Trihexyltetradecylphosphonium bis(2,4,4 trimethylpentyl) phosphinate were completely soluble in the base oils and are assumed to exhibit better tribological performance. Value. Ionic liquids are excellent solvents and are easily miscible in bio-lubricants and therefore can be used as additive with minor modifications. They produce less ash content and hence are environment friendly. IL-based bio-lubricants have the tendency to replace conventional lubricants regarding their tribological applications. However, further work on improving bio-lubricant’s wear characteristics is needed for complete replacement of mineral oil-based lubricants 30cm.

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Synthesis and Tribological Analysis of CuO and TiO2 Nanoparticles based Bio-lubricants /

By Waqas, Muhammad . . 70p. 30cm.

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Synthesis and Tribological Analysis of CuO and TiO2 Nanoparticles based Bio-lubricants /

By Waqas, Muhammad . . 70p. 30cm.

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Synthesis and Tribological Analysis of MoS2 and ZnO Nanoparticles Based Bio-Lubricants /

By Hanif, Muhammad Talha . . 62p. , Due to the increasing demand of conventional energy source, depletion of conventional energy source emphasized the world’s automotive industries to shift towards a renewable source of energy. The purpose of this study is to produce the TMP (Trimethylolpropane) based bio-lubricant (renewable energy source) from different feedstock of vegetable oils and analyze their physicochemical properties when nanoparticles were added to these bio-lubricants. In this work, cottonseed oil, rattan jot oil and waste cooking oil was converted to TMP based bio-lubricant by a two-step based catalyzed esterification. In first step biodiesel was produced from raw vegetable oil and in the second step TMP based bio-lubricant was produced in the presence of sodium methoxide as catalyst. Two types of nanoparticles (MoS2 and ZnO) were used to make the nanolubricants, and their effects on physicochemical properties of lubricants are investigated at one weight percent concentration of nanoparticles. The produced TMP based bio-lubricants from three feedstock oils have a viscosity index of 194,167 and 118 while flash points of produced bio-lubricants were found 175oC, 155oC and 150oC. Other physicochemical properties were also comparable with the commercial lubricants but there is a need to further increase the viscosity of bio-lubricants. With the addition of nanoparticles, the flash point, pour point, density and TAN increases while the viscosity of the nanolubricants was decreased. The addition of nanoparticles reduced the viscosity of two oil samples (CSO and WCO) significantly. A viscosity reduction of 30–40% was recorded for each type of nanoparticle. In case of RJO there was an increase in viscosity by 20-25%. Bio-lubricants fail to give positive results with ZnO nanoparticles while PAO show synergetic behaviors with ZnO nanoparticles. There is a need to check the nano lubricant’s tribological behavior that contains more than one nanoparticles. Due to the non-toxic nature of these lubricants, they can be used as primary lubricant in pharmaceutical industries. These can also be used in blended form with synthetic lubricants in IC engines. The viscosity of the bio-lubricant can also be improved by lowering the vacuum pump pressure. However, more work on improving the physicochemical properties of bio-lubricants is required before they can completely replace mineral oil-based lubricants. 30cm.

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Tribological analysis of Titanium Oxide (TiO₂) based BioLubricants at various operating conditions /

By Shah, Muhammad Usama Habib . . 80p. , Mechanical components operating under boundary lubrication experience high friction and wear which lead to energy losses and faster equipment damage. Traditionally, mineral oil–based lubricants have been used to overcome these issues but their declining availability and environmental impact have encouraged a shift toward renewable, eco-friendly bio-lubricants. While bio-lubricants are sustainable and biodegradable, their performance often declines at high temperatures and heavy loads due to lower thermal stability and inconsistent wear resistance. Using nanoparticles in bio-lubricants helps improve their performance by forming a protective film, lowering surface contact and maintaining stable friction behavior. Titanium dioxide (TiO₂) was chosen in this study for its chemical stability, low toxicity and ability to form protective tribofilms. Cottonseed Oil (CSO), Rattan Jot Oil (RJO), Waste Cooking Oil (WCO) and synthetic Polyalphaolefin (PAO) were tested with and without 1 wt% TiO₂ using a four-ball tribometer at 75°C and 100°C under 147N and 392N loads. The coefficient of friction (COF), wear scar diameter (WSD) and surface roughness were measured. Worn surface analyses were conducted using an Olympus DSX-1000 microscope. RJO+TiO₂ showed the best performance, achieving a 65% reduction in COF and 37.5% reduction in WSD at 100°C–147 N. CSO+TiO₂ also performed strongly, with a 62% reduction in WSD, while WCO+TiO₂ gave the worst results, with 111% higher WSD and 36% higher COF under 100°C–392 N due to nanoparticle agglomeration and unstable lubrication films. These results show that TiO₂ nanoparticles can significantly enhance the friction and wear performance of bio-lubricants, with RJO+TiO₂ emerging as the most reliable choice for high-load boundary lubrication applications. 30cm.

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