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Modeling and Optimization of Friction Stir Welding Parameters for Joining Dissimilar Aluminum Alloys
Get PDFThe objectives of this work are to optimize the process parameters on the mechanical properties (ultimate tensile strength (UTS) and ductility) of dissimilar joints between AA5454 and AA7075 produced by friction stir welding and to determine which of them is significant by using Taguchi L16 optimization method. Seven parameters at two levels were selected in this study. The selected parameters are tool rotational speed, traverse speed, pin profile (based on taper angle), D/d ratio, tool tilt angle, plunge depth, and base metal location. Then, mathematical models are built as function of significant parameters/ interactions using Response Surface Methodology. The results of this work showed that the rotational speed, traverse speed, D/d ratio and plunge depth are significant parameters in determining UTS (Mean, Signal to noise ratio (S/N)) at different confidence levels, but pin profile, location of base metal and tool tilt angle are insignificant parameters at any confidence levels. The traverse speed has the highest contribution to the process for UTS about 18.577 % and 16.943 % for S/N ratio and mean, respectively. The accuracy of the models according to the UTS is 97.678 % and 99.56 %for mean and S/N ratio, respectively. The maximum joint efficiency, compared to the strength of the AA5454, is 85.3%
Study of Changes in Physical Parameters of compost and vermicompost of Eucalyptus leaf litters
Get PDFVermicompost and compost of leaf litter of Eucalyptus was studied in plastic bins in duplicate sets with two different proportions (100 % and 50 %). For vermicompost experiments, epigeic earthworm species Eisenia foetida and Eudrilus eugeniae were employed at 10-10 numbers each per vermicompost bins. Cattle dung was taken as control. During the entire process physical factors viz. temperature, pH, moisture content and biomass were measured and compaired. The results were reveal that initial temperature was 35°C ± 2°C in both vermicompost and compost leaf litter and after several weeks, it was set at minimum level. In 50 % leaf litter temperature was 2-3°C higher than 100 % leaf litter. pH of both vermicompost and compost mixtures were acidic in beginning phase while set at alkaline at final stage. Vermicompost had lower pH than compost. Moisture content of leaf litter also decreased in initial phase due to generation of metabolic heat but at later phase it was increased due to decreasing of metabolic heat. More changed was seen in 100 % leaf litter followed by 50 % and then cattle dung. Biomass of leaf litter was more decreased in 100 % waste then 50 % and cattle dung
Exergy Models and Tar Removal Techniques in Biomass Gasification
Get PDFQuest for higher conversion efficiency and reduced environmental impact has increased the focus on renewable energy sources. Biomass is a sustainable form of energy that can be used as an alternate of fossil fuels through biomass gasification. Gasification is one of the most used methods for converting biomass into syngas that is a usable form of energy. The biomass gasification serves as a promising process for energy production. However, uncertainty in process variables and formation of tar has been a challenge in efficient process design and operation. This paper contains literature review of different models used for gasification, tar removal techniques along with Fischer Tropsch reactions for conversion of biomass to liquid fuels. The paper shows circulating and bubbling fluidized bed gasifier as the most efficient model for tar removal and greater exergy efficiency
Moderating Effect of Confidence in Solving Problem and English Achievement on the Performance of Fourth Year Students in Physics
Get PDFThe study aimed to determine the influence of problem-solving confidence and English achievement on the performance of fourth year students in physics. Specifically, it sought to find out whether English achievement significantly moderate the effect of problem-solving confidence on the performance in physics. Descriptive- predictive design was utilized in the study. The study was carried out in F. Bangoy National High School to sixty fourth year students. Mean and moderated regression were used as tools in the analysis of data. Results revealed that the level of problem-solving confidence in physics was moderate; the level of academic achievement in English was proficient and the level of performance of fourth year students in physics was also proficient. Further, English achievement significantly moderates the effect of problem-solving confidence on the performance of fourth year students in physics. Therefore, it was recommended to strengthen the connection of learning English and problem-solving ability through activities that encourage students to analyze and think critically in order to arrive at a correct solution
Evaluation of Stiffness and Parametric Modelling of XY Flexure Mechanism for Precision Applications
Get PDFIn miniaturized scale electro-mechanical framework (MEMS) flexural instruments are generally utilized in light of their preferences, frictionless and wear less movement and high accuracy. Flexures rely upon material versatility for their usefulness. In flexure component, movement is created because of flexibility of the shaft from which it is made. One of the run of the mill favorable circumstances of flexural system is to increase exact twisting and adaptability to acquire movement wanted way. This paper manages outline, examination and displaying of XY flexure instrument which depends on twofold parallelogram flexure (DFM). The XY system exhibited has solid structure and it depends on twofold parallelogram flexure. Limited component model and investigation is completed in ANSYS 15. Static examination is done to discover constrain avoidance attributes of instrument. Parametric examination is utilized to improve outline parameters of flexure shaft. Limited component examination (FEA) result approves investigative outcomes of component
Anticancer Herbs for Improving the Quality of Life
Get PDFIn the world, there are many systems of traditional medicine. Cancer is the major public health burden both in developing and developed countries. Around 50% of existing medicines for cancer treatment have plants origin. Anticancer property of some plant extracts proven to be significantly effective in the treatment of cancer. Many herbs like sadabahar, turmeric, Kalonji, cannabis, garlic, flaxseed contain active components which may be effective in prevention and treatment of many cancers. The present review focuses on the evidence of health benefit of various herbs though recent human and animal studies.
Biological Control of Anthracnose Disease of Tomato Using Ethanolic Extracts of Azadirachta Indica and Nicotiana Tabacum
Get PDFTomato is a commercially important vegetable throughout the whole world and its availability all the year is grossly affected by anthracnose disease, hence, the need for an effective bio-control that is affordable and user friendly. This study therefore investigated the inhibitory effect of ethanol extracts of Azadirachta indica and Tabacum nicotianaon the mycelium growth of fungi associated with anthracnose disease of tomato. Tomatoes that showed black circular lesions with concentric ring and black spores were bought from Aleshinloye market in Ibadan; samples (3×3mm) from the sterilized margin of the lesion were inoculated on potato dextrose agar and observed for mycelium growth for five days. The obtained cultures were then sub cultured to obtain pure cultures which were introduced into healthy tomato fruits to confirm koch’s postulate. The in-vitro antifungal effects of ethanol extracts of Azadirachta indica and Nicotiana tabacum on isolated fungus causing anthracnose disease of tomato was investigated using agar dilution method. Based on cultural and microscopic characteristics of conidia, Colletotrichum coccodewas identified as organism causing anthracnose disease of tomato. The antifungal effect of the two ethanol plant extracts revealed that Azadirachta indica had the highest inhibitory effect of (45.00cm) at 100mg/ml and the least effect of (38.00cm) at 50mg/ml. Nicotiana tobacum equally had its highest inhibitory effect of (58.00cm) at 100mg/ml and lowest effect of (40.57cm) at 50mg/ml. This result also showed that Nicotiana tobacum had the highest inhibitory effect on Colletotrichum coccode than Azadirachta indica. Conclusively, the use of Tobacco and Neem plant extracts has antifungal activity against Colletotrichum which is responsible for Anthracnose disease of tomato. The plant could be a veritable and cheaper substitute for conventional drugs since the plant is easily obtainable and the extract can easily be made via a simple process of maceration or infusion
The Solar Flux and Sunspot Number; A Long-Trend Analysis
Get PDFWe investigate the nature of monthly sunspot numbers and solar flux F10.7 by employing the linear and multiple regression techniques. We observed a brilliant correlation between monthly mean sunspot number and F10.7. We observed that even in deep solar minimum there exist some magnetic activities. We obtained the coefficient of determination R2 to be 0.9533. We estimated the correlation coefficient for solar flux F10.7 and sunspot number to be 0.97. We extrapolated the F10.7 back to the year 1700 and observed a good correspondence between the modelled F10.7 and sunspot nature. We also found a very good correspondence between the modelled and observed solar flux F10.7
Antibiotic Susceptibility Profiles of Bacteria from Diabetic Foot Infections in Selected Teaching Hospitals in Southwestern Nigeria
Get PDFOne of the serious complications associated with diabetes is foot ulcer and this condition affects the quality of life in patients in all classes, races and ages. Chronic wounds are prone to colonization by wide array of microorganisms which could be extremely hazardous to patients if effective and timely therapeutic intervention is not made. This study was conducted to determine the antibiotic susceptibility profiles of bacteria from diabetic foot infections in southwestern Nigeria. Samples were collected from a total of 142 diabetic foot ulcer patients with moistened sterile cotton swabs. Nutrient agar, Mac-Conkey agar, blood agar and mannitol salt agar media were used for the isolation of total viable bacteria, Gram-negative non-spore forming lactose fermenters, fastidious bacteria and staphylococci, respectively. Morphological and biochemical characteristics of pure cultures were determined in accordance with standard laboratory criteria. API 20 E and API 20 NE were used for the confirmation of identity of the bacterial isolates. The disc diffusion technique was employed for the determination of antibiotic susceptibility of bacterial isolates in accordance with standard procedures. The antibiotics investigated included amikacin, amoxicillin, ampicillin, ceftazidime, cefazolin, ceftriaxone, chloramphenicol, ciprofloxacin, clindamycin, gentamicin, imipenem, linezolid, methicillin, netilmicin, ofloxacin, oxacillin, penicillin, piperacilin, sulfamethoxazole, trimethoprim and vancomycin. One hundred and seventy-seven isolates were encountered and these were characterized into eleven bacterial species. These included Staphylococcus aureus (22.03%), Pseudomonas aeruginosa (16.95%), Staphylococcus epidermidis (12.43%), Proteus mirabilis (8.48%), Klebsiella pneumoniae (7.91%), E. coli (7.35%), Staphylococcus saprophyticus (6.78%), Streptococcus pyogenes (5.65%), Morganella morganii (5.09%), Citrobacter freundii (4.52%) and Acinetobacter baumannii (2.83%). Gram-negative bacteria showed 76.99% susceptibility to the antibiotics while 22.85% was resistant. Gram-positive bacteria showed 93.75% susceptibility and 5.01% resistance to the antibiotics. This study revealed that there is no definite aetiologic bacterial agent for diabetic foot infections and many of the associated bacteria are sensitive to certain antibiotics
Infant Screening System Based on Cry Analysis
Get PDFAcoustical investigation of infant cries has been a clinical and research focus in the recent years. Findings of several studies reveal the importance of cry as a useful window for early detection of several diseases and communication difficulties such as hearing impairment, intellectual disabilities, cerebral palsy etc. This motivates us to use a minimal interface system that can automatically classify infant cries into normal and pathological with the help of state-of-the-art machine learning strategies. In this paper, we propose a software program for screening infants based on their cries. The proposed system is able to detect & classify infant cries into normal and pathological based on the acoustic input. To build and train the system, infant cries of normal and Low Birth Weight (LBW) newborn within 7 days of birth were considered. A pain induced cry elicited using the routine intramuscular immunization was recorded using a standard Olympus LS-100 recorder which was held about 10 centimetres away from the infant’s mouth. The acoustic correlates of these cries were used to build the software tool. Artificial Neural Network was employed to improve its functionality. Therefore, we propose a screening tool for further accessibility and large-scale implementation