14 research outputs found
Comparison Of Fibers Properties Of Azadirachta Indica And Acacia Arabica Plant For Lightweight Composite Application
No full textIn this paper, the bark of Azadirachta Indica and Acacia Arabica plant is analysed for investigating and comparing. The aim is to investigate the potential use of these fibres as reinforcements in polymeric materials. The physicochemical properties of Azadirachta Indica fibres (AIFs) and Acacia Arabica fibres (AAFs) are examined by chemical constitutions, X-ray diffraction, thermogravimetry analysis, Fourier transform infrared spectroscopy analysis, and surface morphological analysis. AIF has a cellulose content of 68.42 wt.%, density of 740 kgm–3, crystallinity index of 65.04%; AAF has a cellulose content up to 68.1 wt.%, density equal to 1028 kgm–3 and crystallinity index of 51.72% respectively. The maximum peak temperature obtained in differential thermogravimetry (DTG) curve is 321.2°C for AIF, and 345.1°C for AAF. The physicochemical results confirm the structural application of AIF and AAF for several industrial fields
INSIGHTS INTO CORONA/CORONAVIRUS DISEASE 2019 PANDEMIC – OPINION VERSUS EVIDENCE
No full textThe pandemic of coronavirus disease 2019 (COVID-19) struck the globe in December 2019, killing lakhs of people and it is continuing in many countries to create havoc. There are lakhs of publications creating evidence about the management of the disease. After seeing thousands of cases, we formed opinions in each field of management and these findings may look more logical. We accept that our opinions differ subtly from the evidence. Regarding the transmission of the disease, it is spread from person to person through inhaled aerosols. If this is going to be 100% true, then the need for personal protective equipment covering the legs seems illogical. Povidone-iodine is antiviral and spreading the same as an ointment inside the nose must be effective to decrease viral load. The other antivirals with questionable efficiency like remdesivir are being used frequently, especially in the pulmonary phase. There are no clear-cut guidelines for primary contacts. Any protective drug intake could have decreased the transmission. It’s a simple logic that the act of sneezing will decrease the viral load. The practice of inhaling turmeric smoke to induce sneezing in the outdoor could have decreased the viral load. We opine that a lymphopenia of <15% can predict a worse outcome in the next 2 days. A computerized computed tomography scan of the chest is to be taken 7 days after the onset of symptoms as the disease usually enters the pulmonary phase only then. The date of onset of symptoms rather than the positive testing date should be considered for timeline management of the case. The undue tachycardia in the 1st week and desaturation below 92% in the 2nd week are the warning signs. The steroids are to be usually prescribed after the 5–6 days. The roles of psychiatric counseling and nutrition were largely underplayed
Exact transient analysis of a circulant queuing network
No full textAbstractCirculant matrices possess unusual and interesting properties. These properties have been exploited to obtain the transient solution in closed form for a circulant queuing network that models a distributed query processing system. The sojourn time of a customer in the circulant queuing network is determined. A semi-Markov generalisation of this network is also studied
Solving the Scheduling Problem in the Electrical Panel Board Manufacturing Industry Using a Hybrid Atomic Orbital Search Optimization Algorithm
No full textEfficient scheduling is critical for the success of any organization. Researchers have proposed numerous strategies for addressing various scheduling problems. The hybrid flow shop (HFS) scheduling is a complex and NP-hard problem that arises in many manufacturing and service industries. This work introduces an optimization technique that utilizes atomic orbitals to address issues in HFS scheduling. Our objective is to reduce makespan (Cmax). Makespan minimization is critical for improving productivity and resource utilization. The standard atomic orbital search optimization algorithm (AOSOA) is hybridized with constructive heuristics to enhance solution quality. The scheduling problem of an electrical panel board manufacturing industry is solved using the hybrid AOSOA (HAOSOA). The results were better than those previously reported. A variety of random test situations of varying sizes and configurations were devised to assess the efficacy of the suggested algorithm. The proposed algorithm’s outcomes were compared against well-known algorithms discussed in the literature. Friedman and Wilcoxon test results indicate that the proposed methodology improves the solution quality in each test instance compared to all the metaheuristics used for comparison. The performance of the proposed algorithm is also evaluated using benchmark problems from the literature. In the first test, the algorithm has a rank value of 1, indicating it performs better than each of the comparing algorithms. In the second test, it is able to find the best makespan for 65 of the 77 problems
Modelling in-plane behaviour of masonry shear walls through a predefined crack pattern at macro level
No full textThis thesis is a study towards in-plane behaviour of masonry shear walls modelled through a predefined crack pattern at macro level. The Semi-Lumped method, proposed by Messali (2015), is analysed in detail to confirm the consequences of the SLM assumptions. This is achieved via literature and numerical validations. The final part of the thesis contains a pilot study towards a combined procedure of the Semi-Lumped Method and the Sequentially linear analysis
Non-proportional loading in sequentially linear analysis for 3D stress states
No full text Sequentially linear analysis (SLA), a non-incremental-iterative approach towards finite element simulation of quasi-brittle materials, is based on sequentially identifying a critical integration point in the model, to reduce its strength and stiffness, and the associated critical load multiplier (λ crit ), to scale the linear analysis results. In this article, two novel methods are presented to enable SLA simulations for non-proportional loading situations in a three-dimensional fixed smeared crack framework. In the first approach, the cubic function in the load multiplier is analytically solved for real roots using trigonometric solutions or the Cardano method. In the second approach, the load multiplier is expressed as a function of the inclination of a potential damage plane and is deduced using a constrained optimization approach. The first method is preferred over the second for the validation studies due to computational efficiency and accuracy reasons. A three-point bending beam test, with and without prestress, and an RC slab tested in shear, with and without axial loads, are used as benchmarks. The proposed solution method shows good agreement with the experiments in terms of force-displacement curves and damage evolution. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Applied Mechanic
Dynamic Simulation and Validation of a Vent and Safety Valve for Cryogenic Flight Tanks
No full textAbstractHigh Thrust Cryogenic Rocket Stages entail the use of a Vent and Relief Valve which can cater to a higher discharge rate. The Vent function is called for during ground servicing operations like tank chilling and pressurant replenishment and during flight to take care of the decrease in ambient pressure and boil-off losses. The Relief function acts as a redundant feature to protect the tanks from catastrophic failure due to structural damage caused by over-pressurization. Nevertheless, this valve needs to be characterized for both these functions during ground tests. This paper describes the modelling of and experimentation on an Inverted Type Pilot Operated Vent and Safety Valve. A mathematical model for simulating the dynamic behavior of this tank-mounted valve is developed. For this, a set of non-linear, first order, coupled ordinary differential equations, based on laws of conservation of mass and energy, are derived using fixed control volume approach. The numerical solution of these equations is obtained using fourth order Runge-Kutta method. The pressure, temperature, flow rate, seat stress and lift thus obtained are plotted to find the characteristic parameters such as cracking pressure, full flow pressure, reseal pressure, opening and closing response, tank pressure decay rate and full flow rate. The valve performance is studied for the effect of main valve outlet orifice and the pilot valve outlet orifice using these simulations. These results are validated by comparing it to the test results
Development of Eco-Friendly Cutting Fluid for Machining of AISI 1010 Steel in Automotive Industry
No full textIn spite of better performance, the disposal of used petroleum-based cutting fluids threatens our environment. Thus, it is essential to develop eco-friendly cutting fluids for performing machining operations in industries. The main contribution of this paper is to develop an eco-friendly cutting fluid for the plain turning of AISI 1010 steel which is used in the automotive industry. In the present work, boric acid (H3BO3) was mixed with the neem seed. Neem seed oil is easily available in many countries including India. The effectiveness of the proposed cutting fluid was evaluated by conducting different tests as per the standards. The mean biodegradability value of the developed cutting fluid is 97% which is better than other cutting fluids. The average cutting force required by the proposed cutting fluid is only 127.2 N which is much less than the cutting force requirements of dry machining and conventional cutting fluids. The average surface roughness of the machined component using the proposed cutting fluid is 122.9 µm. The mean flank wear of the tool is only 289 µm. The flash point of the proposed cutting fluids is more than 250 °C which is better than the conventional cutting fluids. The fire point of the neem oil-based cutting fluids is 300 °C. The results of the stability test and the microhardness test revealed the effectiveness of the proposed cutting fluids. The results obtained in this work are superior to several other cutting fluids reported in the existing literature. Hence, it is suggested to replace the existing petroleum-based metal cutting fluid with this eco-friendly cutting fluid in the automotive industry in Hosur, India
Morpho-syntactic concept and contribution of Tholkaappiyar : a view from a different prism
No full textThe concept of morpho-syntax is defined as ‘the study of grammatical affixes or linguistic units that have both morphological and syntactic properties’. The author of Tholkaappiyam, the earliest written Tamil grammar of 300 B.C., explains this concept exhaustively in different chapters. This notion of modern Linguistics is to be added as one of the levels of language for research and teaching grammar as well. A per the author of the grammar, tense is a morpho-semantic feature, which is added to finite verbs. Tense marker attributes to the meaning of the sentence and not to the sentence structure. That was his concept and contribution to the field of Linguistics. Features like, metonymy, ambiguity, gerund formation, etc., in the grammar, support the concept proposed. Selected verses from Tholkaappiyam have been quoted for the sustenance of his view. Additionally, this article brings in another very important concept of ‘mid-fix’, which is a new contribution to the field
