ORCID Profile
0000-0003-0429-5355
Current Organisations
University of Engineering and Technology Lahore
,
University of Engineering and Technology
,
University of Pittsburgh
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: MDPI AG
Date: 28-04-2022
DOI: 10.3390/PR10050876
Abstract: Over the years, due to the surge in energy demand, the use of alternative fuels has emerged as an interesting area of research. In the current work, a comparative study was conducted by employing gasoline, 6% ethanol–gasoline (E6), and 12% ethanol–gasoline (E12) in a spark-ignition engine. Performance, emissions, and lube oil damage tests were conducted at a constant load by varying engine speed. E12 showed improved performance, i.e., 7.82% higher torque and 14.69% improved brake thermal efficiency (BTE) in comparison with neat gasoline. In addition, CO, CO2, HC, and NOx emissions were found to be minimal for E12. Furthermore, lubricating oil properties (kinematic viscosity, flash point, and total base number (TBN)) and wear debris (iron, aluminum, and copper) showed a visibly improved performance with gasoline compared to E6 and E12. The highest decline in kinematic viscosity of 27.87%, compared to fresh oil, was recorded for E12. Thus, the lube oil properties have to be modified according to the chemical properties of the alternative fuel.
Publisher: MDPI AG
Date: 20-08-2021
DOI: 10.3390/SU13169373
Abstract: The prevailing massive exploitation of conventional fuels has staked the energy accessibility to future generations. The gloomy peril of inflated demand and depleting fuel reservoirs in the energy sector has supposedly instigated the urgent need for reliable alternative fuels. These very issues have been addressed by introducing oxyhydrogen gas (HHO) in compression ignition (CI) engines in various flow rates with diesel for assessing brake-specific fuel consumption (BSFC) and brake thermal efficiency (BTE). The enrichment of neat diesel fuel with 10 dm3/min of HHO resulted in the most substantial decrease in BSFC and improved BTE at all test speeds in the range of 1000–2200 rpm. Moreover, an Artificial Intelligence (AI) approach was employed for designing an ANN performance-predicting model with an engine operating on HHO. The correlation coefficients (R) of BSFC and BTE given by the ANN predicting model were 0.99764 and 0.99902, respectively. The mean root errors (MRE) of both parameters (BSFC and BTE) were within the range of 1–3% while the root mean square errors (RMSE) were 0.0122 kg/kWh and 0.2768% for BSFC and BTE, respectively. In addition, ANN was coupled with the response surface methodology (RSM) technique for comprehending the in idual impact of design parameters and their statistical interactions governing the output parameters. The R2 values of RSM responses (BSFC and BTE) were near to 1 and MRE values were within the designated range. The comparative evaluation of ANN and RSM predicting models revealed that MRE and RMSE of RSM models are also well within the desired range but to be outrightly accurate and precise, the choice of ANN should be potentially endorsed. Thus, the combined use of ANN and RSM could be used effectively for reliable predictions and effective study of statistical interactions.
Publisher: MDPI AG
Date: 05-05-2023
DOI: 10.3390/SU15097601
Abstract: Growing environmental concerns over global warming and depleting fossil fuel reserves are compelling researchers to investigate green fuels such as alcoholic fuels that not only show the concrete decrement in emissions but also enhance engine performance. The current study emphasizes the influence of different alcoholic fuel blends in gasoline on engine performance and emissions for an engine speed ranging from 1200 to 4400 rpm. The obtained performance results demonstrate that the brake power and brake thermal efficiency (BTE) increased with an incrementing blend percentage of ethanol and methanol in gasoline (EM). The minimum brake specific fuel consumption (BSFC) was ascertained using pure gasoline followed by E2 and then E5M5. The NOx and CO2 emissions can be described in the decreasing order of E, EM and gasoline due to same trend of exhaust gas temperature (EGT). CO results were in reverse order of CO2. HC emissions were found in the increasing order of E, EM and pure gasoline. E10 performed better among all blends in terms of less exhaust emissions and engine performance. However, EM blended with gasoline significantly reduced NOx. E5M5 produced 1.9% lower NOx emission compared to E10 owing to 1.2% lower EGT. Moreover, greenhouse gases such as CO2, which is mainly responsible for global warming reducing by 1.1% in case E5M5 as compared to E10.
Publisher: MDPI AG
Date: 23-08-2022
DOI: 10.3390/SU141710485
Abstract: The lubrication phenomenon is used to reduce friction and wear between two rubbed surfaces, such as in engine and cutting processes. Different oils such as mineral oil and synthetic lubricant are being used for this purpose. With the passage of time, the demand of energy will get higher and natural resources and mineral lubricants will be diminished. Furthermore, biodegradation of mineral oil is too slow, and it remains on the surface of earth for a long period of time, creating atmospheric pollution. To overcome this problem, bio lubricants are being used to reduce wear and friction due to their high biodegradability. In order to increase the lubrication capacity of castor oil, a 1 wt. % concentration of MoS2 nanoparticles was added to the base oil. Moreover, to stabilize the additives, 2 wt. % gum arabic and 1 wt. % Oleic acid (OA) were also added. Then, multiple tests, such as of physicochemical properties, Fourier transform infrared (FTIR), and atomic absorption spectroscopy (AAS) of synthetic lubricant and conventional lubricant, were carried out before and after the operational running of 100 h on the diesel engine for each lubricant at 75% throttle, 2200 rpm, and 50% of total load. The results show that the behavior of newly prepared MoS2-based synthetic lubricant possessed higher characteristics in some physicochemical properties and was marginally lacking in other properties compared to shell lubricant. The flash point and specific gravity of synthetic lubricant were decreased compared to shell oil, with relative decreases of 0.27% and 1.15%, respectively. Ash and kinematic viscosity of 40 °C had a relative increase of 4.17% and 1.61%, respectively, and at a kinematic viscosity of 100 °C, the pour points and total base number (TBN) were relatively increased at 1.09%, 6.02%, and 1.38%, respectively, with respect to the properties of the shell lubricant. Moreover, this analysis evaluated that the reduction of wear and tear in synthetic lubricant regarding chromium (Cr), copper (Cu), and iron (Fe) was decreased by 21.12%, 3.39%, and 0.96%, respectively, but in the case of aluminum (Al) the wear and tear was marginally increased, at 1.17%, compared to shell lubricant. In the case of calcium (Ca) and zinc (Zn), the concentration was decreased by 3.59% and 17.41%, respectively. The FTIR analysis shows that all the peaks of the synthetic lubricant and shell lubricant were overlapping each other in the first three regions of the mid-IR spectra from 4000 to 1500 cm−1 and had the same functional groups—hydroxyl stretch (O-H), alkanes (C-H), carbonyls (C=O), aromatic amines (C-N), and alkyl halides (C-Br)—which were attached but fluctuating in the fingerprint region. The results show that shell lubricant can be replaced with MoS2-based synthetic lubricant because the latter has superior friction reduction and load-bearing capability and can compete favorably with commercial shell oil in wear protection when additivated with MoS2-based nanoparticles, and hence can be a good alternative for diesel engine oil.
Publisher: Elsevier BV
Date: 08-2011
DOI: 10.1038/JID.2011.115
Abstract: The majority of Merkel cell carcinomas (MCCs) are associated with the recently identified Merkel cell polyomavirus (MCV). However, as it is still unclear to which extent the presence of MCV impacts tumor characteristics or clinical outcome, we correlated the MCV status of tumor lesions obtained from 174 MCC patients including 38 MCC patients from Australia and 138 MCC patients from Germany with clinical characteristics, histomorphology, immunohistochemistry, and course of the disease. MCV DNA was present in 86% of MCCs and, in contrast to previous reports, no significant difference in MCV prevalence was present between Australian and German MCC cases. When patients were stratified according to their MCV status, only tumor localization (P=0.001), gender (P=0.024), and co-morbidity, i.e., frequency of patients with previous skin tumors (P=0.024), were significantly different factors. In contrast, year of birth and diagnosis, age at diagnosis, or histological type and features representing the oncogenic phenotype such as mitotic rate or expression of p16, p53, RB1, and Ki67 were not significantly different between MCV-positive and MCV-negative MCCs. MCV status also did not influence recurrence-free, overall, and MCC-specific survival significantly. In summary, although MCV-positive and MCV-negative MCCs may have different etiologies, these tumors have comparable clinical behaviors and prognosis.
No related grants have been discovered for Muhammad Usman.