The objective of this investigational analysis was to study the influence of process variables on the response during the drilling of LM6/B4C composite materials. Stir casting was employed to produce ...the LM6/B4C composites. A Vertical Machining Center (VMC) with a dynamometer was used to drill the holes and to record the thrust force. An L27 orthogonal array was used to carry out the experimental work. A grey relational analysis (GRA) was employed to perform optimization in order to attain the lowest Thrust Force (TF), Surface Roughness (SR) and Burr Height (BH). For minimal responses, the optimum levels of the process variables viz. the feed rate (F), spindle speed (S), drill material (D) and reinforcing percentage (R) were determined. The process variables in the drilling of the LM6/B4C composites were indeed optimized, according to confirmational investigations. The predicted Grey Relational Grade was 0.846, whereas the experimental GRG was 0.865, with a 2.2% error—indicating that the optimization process was valid.
Drilling is a very important hole making process. It is very much useful for assembly of parts. Incorporation of hard ceramic particles into the matrix of metallic composites made them difficult to ...machine. So, it becomes inevitable to optimize the drilling parameters. The foremost objective of this research work is to fabricate Hybrid Aluminium Matrix Composites(AMCs) of LM6/B4C/Fly Ash with 3%, 6% & 9% by weight percentages of both reinforcements, equally using stir casting technique. The next objective is drilling of composites with feed, speed, drill and percentage of reinforcement as input process parameters at three levels each by Taguchi’s Design of Experiments approach. The final objective is to optimize the drilling process parameters for achieving low thrust force, low surface roughness and minimum burr height using the multi-objective Grey Relational Analysis. Results reveal that drill material plays a major role, being closely followed by feed and speed.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Introduction: With modern advances, Ultrasonography (USG)- guided regional block techniques have improved nerve blockade with lesser drug usage and maximum safety for patient care. The widely ...appreciated outpatient surgical care has compelled us to apply the fastest and safest anaesthesia technique. For lower limb surgeries, USG-guided Sciatic Femoral Nerve Block (SFNB) is an emerging alternative to Spinal Anaesthesia (SA). Aim: To compare the safety and efficacy of both techniques in terms of haemodynamic stability, quality of block, and postoperative analgesia. Materials and Methods: A randomised double-blind study conducted at GCS Medical College, Hospital, and Research Centre, Ahmedabad, Gujarat, India, on 80 patients aged 18 to 70 years of either sex, with American Society of Anaesthesiology (ASA) Grade 1 to 3, undergoing below-knee surgeries was divided into two groups. Group A received USA with 1.5 mL hyperbaric inj. ropivacaine 0.75%, and Group B received USGguided SFB with inj. ropivacaine 0.5% 30 mL (15 mL for sciatic nerve and 15 mL for femoral nerve block). Preparation Time (PT), Surgical Anaesthesia Time (SAT), haemodynamic changes, quality of block, Longevity of Anaesthesia (LoA), time of first rescue analgesia, time of spontaneous urination, readiness to discharge, and patient satisfaction were recorded. The statistical analysis was carried out using Statistical Package for Social Sciences version 23.0 (SPSS Inc., Chicago II, USA). The p-value was derived by unpaired t-test and Chi-square test. Results: PT and SAT were higher in Group B (12.10±2.02 mins and 15.74±1.58 mins) than in Group A (6.15±1.12 mins and 8.23±1.45 mins). LoA time and time to first rescue analgesic were higher in Group B (284.10±54.44 mins and 265.71±33.69 mins) than in Group A (138.75±23.30 mins and 132.40±17.41 mins). Time to first spontaneous urination and readiness to discharge were shorter in Group B (136.42±18.40 mins and 158.39±10.78 mins) than in Group A (162.20±26.54 mins and 181.53±18.18 mins). Haemodynamic stability was excellent in both groups with no significant fluctuation. Motor blockade of Bromage 3 grade was achieved in 40 and 38 patients in Group A and B, respectively. The development of VAS score >3 was faster in Group A than in Group B (35 versus 2) at the end of three hours. No adverse events were observed in any patient. Conclusion: USG-guided SFB offers a safe and efficient alternative to Unilateral SA (USA) with satisfactory blockage, stable haemodynamics, and better postoperative analgesia for below-knee surgeries.
Due to their abrasive behaviour, metal matrix composites (MMCs) are difficult to machine, so it is necessary to develop a suitable technology for their efficient machining. The ultimate goal of the ...research is to study the impact of process variables such as reinforcement, drill type, speed and feed rate on the thrust force and burr height during AMCs drilling. Aluminium Matrix Composites were manufactured with LM6 aluminium alloy as matrix and B4C as reinforcement through the low cost stir casting process. Experiments were performed using L27 orthogonal array in a CNC Vertical Machining Centre equipped with cutting tool dynamometer to measure the thrust force and burr-height was measured using vision measuring system. Experimental results demonstrated that this strategy enhances the performance characteristics expected in the drilling phase.
The present research involves the opportunity of utilising the signal to noise (S/N) ratio analysis to set machining factors in the drilling of aluminium alloy LM6-Fly ash composites (AMCs). The ...purpose of this research is to understand, during drilling of AMCs, the consequences of variables, feed rate, spindle speed, drill material and amount of reinforcing material on surface roughness and burr height. AMCs are formed with LM6 (Al alloy) as continuous component via the stir casting process and fly ash as reinforced content. The Taguchi design strategy is a widely accepted method which is used to produce quality products that require minimum commitment. Likewise, the L27 orthogonal array is used for conducting experiments. The response table, response graphs and analysis of variance (ANOVA) illustrate the prospective atmosphere and the impacts of input process variables. Taguchi technique considerably enhances the drilling operation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Abstract
Neural networks are abstract structures modeled by the brain to store evidence in the form of spikes. When introduced in VLSI circuits, neural networks are supposed to have new computer ...processing methods and economically viable computer simulations. We suggest a novel set of training examples for neural nets spatial and temporal coding in this article. In just this procedure, going through the roof neuronal is programmed to promote analogue VLSI applications with resistor analogue memory, from which incredible energy consumption can be accomplished. Can also suggest many strategies to boost efficiency on a model training and prove that the proposed method’s SVM classifier is as high as it was for the retrained dataset’s province temporal coding Computational Intelligence algorithms. Incorporating the developed framework can even recommend very massive circuit boards. The frequency analogue circuits utilize intermittent processing to reimburse capacitance processes, unlike the traditional analogue voltage and current type circuitry being used compute-in-memory circuits. Even though connectors lacking operating amps can still be constructed, it can also be controlled with incredibly low energy consumption. Finally, the preservation of the designed highlights algorithms toward alterations from the system’s production phase and is inevitable in analogue VLSI deployment.
Increasing work efficiency, improving psychological health, decreasing turnover, turnover intention, and absenteeism may be dependent on organizational commitment of an employee. This study was ...carried out to identify the predictors of organizational commitment among university nursing faculty within Kathmandu Valley, Nepal.
A cross-sectional analytical study was conducted based on a sample of 197 nursing faculty selected from 18 nursing colleges affiliated to 5 universities in Kathmandu Valley by using a proportionate stratified random sampling technique. Structured questionnaires regarding socio-demographic information, perceived faculty developmental opportunity, job satisfaction, perceived organizational support, and organizational commitment were used for data collection. Double data entry and data cleaning were done by using Epi-data software; and data analysis was carried out with SPSS version 16 software. Binary regression analysis was used to identify the predictors of organizational commitment and the adjusted odds ratio (AOR) was also calculated.
The findings of this study showed that a majority of respondents had moderate level of organizational commitment (68%) followed by high level (29%) and low level (3%). This study also revealed that the nursing faculty who had a master's degree in nursing, a permanent appointment, and job satisfaction had a high level of organizational commitment. On the contrary, this study also revealed that the nursing faculty who were in the position of assistant instructor to assistant lecturer level and more than 5 years of work experience within same organization were less likely to have a high level of organizational commitment.
Nursing faculty within Kathmandu Valley have a moderate level of organizational commitment. The predictors of organizational commitment are higher education in nursing, position, type of appointment, current organizational tenure, and job satisfaction. Therefore, an organizational authority must pay attention to the modifiable predictors of organizational commitment to enhance organizational commitment of its nursing faculty. This will help to reduce faculty turnover, increase quality of teaching and student's satisfaction.
Thermoelectric (TE) devices can be used reversely as a heat pump for refrigeration (heat management) and mostly oxide materials are used in these devices. Metal oxide-based TE materials possess ...several advantages compared to metal chalcogenides. These materials can be employed, since they are environment-friendly and cost-effective. TE performance can be easily tuned and this can be achieved through composition and structure. In the present work, Na
0.77
CoO
2
/nano Co
3
O
4
composites are chosen. Although Na
x
CoO
2
possesses superior TE performance to other oxide-based materials, its application has been limited due to its instability in air. It decomposes into the insulating Co(OH)
2
and/or CoCO
3
by absorbing moisture and/or CO
2
from the ambient environment. Upon heating, both Co(OH)
2
and CoCO
3
decompose further into the insulating Co
3
O
4
and CoO. Therefore, it is important to explore the chemical stability of Na
x
CoO
2
. This study analyses the reasons for the chemical instability of Na
x
CoO
2
without impairing its TE properties. Na
0.77
CoO
2
was prepared by the solid-state synthesis method and the single phase was observed in XRD. Again XRD was taken after 15 days, to analyse the stability of the prepared sample. The peaks corresponding to Na
0
.
77
CoO
2
disappeared. The reasons for this instability were analysed and possible solutions are suggested.
The aim of this research work is to investigate the effect of the process parameters on the thrust force and burr height during the drilling of hybrid metal matrix composites. Stir casting was used ...to manufacture hybrid MMCs. Fly ash and boron carbide were the reinforcements used in the manufacture. Tests were carried out in a computer-controlled vertical machining center together with a cutting tool dynamometer to measure the thrust power. The experiments were conducted based on a L27 orthogonal array. Multi-response optimization was performed using grey relational analysis for obtaining minimum thrust force and minimum burr height. The optimum level of input factors namely feed, spindle speed, drill material and reinforcement percentage was defined for low thrust force and low burr height. Confirmation experiments showed that the drilling parameters in the drilling of hybrid metal matrix composites are precisely optimized.
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