Search results for: marine diesel engine (two and four stroke)
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 2059

Search results for: marine diesel engine (two and four stroke)

1729 Solar-Thermal-Electric Stirling Engine-Powered System for Residential Units

Authors: Florian Misoc, Cyril Okhio, Joshua Tolbert, Nick Carlin, Thomas Ramey

Abstract:

This project is focused on designing a Stirling engine system for a solar-thermal-electrical system that can supply electric power to a single residential unit. Since Stirling engines are heat engines operating any available heat source, is notable for its ability to generate clean and reliable energy without emissions. Due to the need of finding alternative energy sources, the Stirling engines are making a comeback with the recent technologies, which include thermal energy conservation during the heat transfer process. Recent reviews show mounting evidence and positive test results that Stirling engines are able to produce constant energy supply that ranges from 5kW to 20kW. Solar Power source is one of the many uses for Stirling engines. Using solar energy to operate Stirling engines is an idea considered by many researchers, due to the ease of adaptability of the Stirling engine. In this project, the Stirling engine developed was designed and tested to operate from biomass source of energy, i.e., wood pellets stove, during low solar radiation, with good results. A 20% efficiency of the engine was estimated, and 18% efficiency was measured, making it suitable and appropriate for residential applications. The effort reported was aimed at exploring parameters necessary to design, build and test a ‘Solar Powered Stirling Engine (SPSE)’ using Water (H₂O) as the Heat Transfer medium, with Nitrogen as the working gas that can reach or exceed an efficiency of 20%. The main objectives of this work consisted in: converting a V-twin cylinder air compressor into an alpha-type Stirling engine, construct a Solar Water Heater, by using an automotive radiator as the high-temperature reservoir for the Stirling engine, and an array of fixed mirrors that concentrate the solar radiation on the automotive radiator/high-temperature reservoir. The low-temperature reservoir is the surrounding air at ambient temperature. This work has determined that a low-cost system is sufficiently efficient and reliable. Off-the-shelf components have been used and estimates of the ability of the Engine final design to meet the electricity needs of small residence have been determined.

Keywords: stirling engine, solar-thermal, power inverter, alternator

Procedia PDF Downloads 248
1728 Effect of Needle Height on Discharge Coefficient and Cavitation Number

Authors: Mohammadreza Nezamirad, Sepideh Amirahmadian, Nasim Sabetpour, Azadeh Yazdi, Amirmasoud Hamedi

Abstract:

Cavitation inside diesel injector nozzle is investigated using Reynolds-Stress-Navier Stokes equations. Schnerr-Sauer cavitation model is used for modeling cavitation inside diesel injector nozzle. The carrying fluid utilized in the current study is diesel fuel. The flow is verified at the beginning by comparing with the previous experimental data, and it was found that K-Epsilon turbulent model could lead to a better accuracy comparing to K-Omega turbulent model. Moreover, the mass flow rate obtained numerically is compared with the experimental value, and the discrepancy was found to be less than 5 percent which shows the accuracy of the current results. Finally, a real-size four-hole nozzle is investigated, and the flow inside it is visualized based on velocity profile, discharge coefficient, and cavitation number. It was found that the mesh density could be reduced significantly by utilizing periodic boundary conditions. Velocity contour at the mid nozzle showed that the maximum value of velocity occurs at the end of the needle before entering the orifice area. Last but not least, at the same boundary conditions, when different needle heights were utilized, it was found that as needle height increases with an increase in cavitation number, discharge coefficient increases, while the mentioned increases are more tangible at smaller values of needle heights.

Keywords: cavitation, diesel fuel, CFD, real size nozzle, mass flow rate

Procedia PDF Downloads 118
1727 MCERTL: Mutation-Based Correction Engine for Register-Transfer Level Designs

Authors: Khaled Salah

Abstract:

In this paper, we present MCERTL (mutation-based correction engine for RTL designs) as an automatic error correction technique based on mutation analysis. A mutation-based correction methodology is proposed to automatically fix the erroneous RTL designs. The proposed strategy combines the processes of mutation and assertion-based localization. The erroneous statements are mutated to produce possible fixes for the failed RTL code. A concurrent mutation engine is proposed to mitigate the computational cost of running sequential mutants operators. The proposed methodology is evaluated against some benchmarks. The experimental results demonstrate that our proposed method enables us to automatically locate and correct multiple bugs at reasonable time.

Keywords: bug localization, error correction, mutation, mutants

Procedia PDF Downloads 247
1726 Cost-Effective Mechatronic Gaming Device for Post-Stroke Hand Rehabilitation

Authors: A. Raj Kumar, S. Bilaloglu

Abstract:

Stroke is a leading cause of adult disability worldwide. We depend on our hands for our activities of daily living(ADL). Although many patients regain the ability to walk, they continue to experience long-term hand motor impairments. As the number of individuals with young stroke is increasing, there is a critical need for effective approaches for rehabilitation of hand function post-stroke. Motor relearning for dexterity requires task-specific kinesthetic, tactile and visual feedback. However, when a stroke results in both sensory and motor impairment, it becomes difficult to ascertain when and what type of sensory substitutions can facilitate motor relearning. In an ideal situation, real-time task-specific data on the ability to learn and data-driven feedback to assist such learning will greatly assist rehabilitation for dexterity. We have found that kinesthetic and tactile information from the unaffected hand can assist patients re-learn the use of optimal fingertip forces during a grasp and lift task. Measurement of fingertip grip force (GF), load forces (LF), their corresponding rates (GFR and LFR), and other metrics can be used to gauge the impairment level and progress during learning. Currently ATI mini force-torque sensors are used in research settings to measure and compute the LF, GF, and their rates while grasping objects of different weights and textures. Use of the ATI sensor is cost prohibitive for deployment in clinical or at-home rehabilitation. A cost effective mechatronic device is developed to quantify GF, LF, and their rates for stroke rehabilitation purposes using off-the-shelf components such as load cells, flexi-force sensors, and an Arduino UNO microcontroller. A salient feature of the device is its integration with an interactive gaming environment to render a highly engaging user experience. This paper elaborates the integration of kinesthetic and tactile sensing through computation of LF, GF and their corresponding rates in real time, information processing, and interactive interfacing through augmented reality for visual feedback.

Keywords: feedback, gaming, kinesthetic, rehabilitation, tactile

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1725 Efficacy of Botulinum Toxin in Alleviating Pain Syndrome in Stroke Patients with Upper Limb Spasticity

Authors: Akulov M. A., Zaharov V. O., Jurishhev P. E., Tomskij A. A.

Abstract:

Introduction: Spasticity is a severe consequence of stroke, leading to profound disability, decreased quality of life and decrease of rehabilitation efficacy [4]. Spasticity is often associated with pain syndrome, arising from joint damage of paretic limbs (postural arthropathy) or painful spasm of paretic limb muscles. It is generally accepted that injection of botulinum toxin into a cramped muscle leads to decrease of muscle tone and improves motion range in paretic limb, which is accompanied by pain alleviation. Study aim: To evaluate the change in pain syndrome intensity after incections of botulinum toxin A (Xeomin) in stroke patients with upper limb spasticity. Patients and methods. 21 patients aged 47-74 years were evaluated. Inclusion criteria were: acute stroke 4-7 months before the inclusion into the study, leading to spasticity of wrist and/or finger flexors, elbow flexor or forearm pronator, associated with severe pain syndrome. Patients received Xeomin as monotherapy 90-300 U, according to spasticity pattern. Efficacy evaluation was performed using Ashworth scale, disability assessment scale (DAS), caregiver burden scale and global treatment benefit assessment on weeks 2, 4, 8 and 12. Efficacy criterion was the decrease of pain syndrome by week 4 on PQLS and VAS. Results: The study revealed a significant improvement of measured indices after 4 weeks of treatment, which persisted until the 12 week of treatment. Xeomin is effective in reducing muscle tone of flexors of wrist, fingers and elbow, forearm pronators. By the 4th week of treatment we observed a significant improvement on DAS (р < 0,05), Ashworth scale (1-2 points) in all patients (р < 0,05), caregiver burden scale (р < 0,05). A significant decrease of pain syndrome by the 4th week of treatment on PQLS (р < 0,05) и VAS (р < 0,05) was observed. No adverse effect were registered. Conclusion: Xeomin is an effective treatment of pain syndrome in postural upper limb spasticity after stroke. Xeomin treatment leads to a significant improvement on PQLS and VAS.

Keywords: botulinum toxin, pain syndrome, spasticity, stroke

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1724 The Potential of Braking Energy Recuperation in a City Bus Diesel Engine in the Japanese JE05 Emission Test Cycle

Authors: Grzegorz Baranski, Piotr Kacejko, Konrad Pietrykowski, Mariusz Duk

Abstract:

This paper discusses a model of a bus-driving scheme. Rapid changes in speed result in a constantly changing kinetic energy accumulated in a bus mass and an increased fuel consumption due to hardly recuperated kinetic energy. The model is based on the results achieved from chassis dynamometer, airport and city street researches. The verified model was applied to simulate the mechanical energy recuperation during the Japanese JE05 Emission Test Cycle. The simulations were performed for several values of vehicle mass. The research results show that fuel economy is impacted by kinetic energy recuperation.

Keywords: heavy duty vehicle, city bus, Japanese JE05 test cycle, kinetic energy, simulations

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1723 Clinical Manifestations, Pathogenesis and Medical Treatment of Stroke Caused by Basic Mitochondrial Abnormalities (Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke-like Episodes, MELAS)

Authors: Wu Liching

Abstract:

Aim This case aims to discuss the pathogenesis, clinical manifestations and medical treatment of strokes caused by mitochondrial gene mutations. Methods Diagnosis of ischemic stroke caused by mitochondrial gene defect by means of "next-generation sequencing mitochondrial DNA gene variation detection", imaging examination, neurological examination, and medical history; this study took samples from the neurology ward of a medical center in northern Taiwan cases diagnosed with acute cerebral infarction as the research objects. Result This case is a 49-year-old married woman with a rare disease, mitochondrial gene mutation inducing ischemic stroke. She has severe hearing impairment and needs to use hearing aids, and has a history of diabetes. During the patient’s hospitalization, the blood test showed that serum Lactate: 7.72 mmol/L, Lactate (CSF) 5.9 mmol/L. Through the collection of relevant medical history, neurological evaluation showed changes in consciousness and cognition, slow response in language expression, and brain magnetic resonance imaging examination showed subacute bilateral temporal lobe infarction, which was an atypical type of stroke. The lineage DNA gene has m.3243A>G known pathogenic mutation point, and its heteroplasmic level is 24.6%. This pathogenic point is located in MITOMAP and recorded as Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke-like episodes (MELAS) , Leigh Syndrome and other disease-related pathogenic loci, this mutation is located in ClinVar and recorded as Pathogenic (dbSNP: rs199474657), so it is diagnosed as a case of stroke caused by a rare disease mitochondrial gene mutation. After medical treatment, there was no more seizure during hospitalization. After interventional rehabilitation, the patient's limb weakness, poor language function, and cognitive impairment have all improved significantly. Conclusion Mitochondrial disorders can also be associated with abnormalities in psychological, neurological, cerebral cortical function, and autonomic functions, as well as problems with internal medical diseases. Therefore, the differential diagnoses cover a wide range and are not easy to be diagnosed. After neurological evaluation, medical history collection, imaging and rare disease serological examination, atypical ischemic stroke caused by rare mitochondrial gene mutation was diagnosed. We hope that through this case, the diagnosis of rare disease mitochondrial gene variation leading to cerebral infarction will be more familiar to clinical medical staff, and this case report may help to improve the clinical diagnosis and treatment for patients with similar clinical symptoms in the future.

Keywords: acute stroke, MELAS, lactic acidosis, mitochondrial disorders

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1722 Mitigation of Offshore Piling Noise Effects on Marine Mammals

Authors: Waled A. Dawoud, Abdelazim M. Negm, Nasser M. Saleh

Abstract:

Offshore piling generates underwater sound at level high enough to cause physical damage or hearing impairment to the marine mammals. Several methods can be used to mitigate the effect of underwater noise from offshore pile driving on marine mammals which can be divided into three main approaches. The first approach is to keep the mammal out of the high-risk area by using aversive sound waves produced by acoustic mitigation devices such as playing-back of mammal's natural predator vocalization, alarm or distress sounds, and anthropogenic sound. The second approach is to reduce the amount of underwater noise from pile driving using noise mitigation techniques such as bubble curtains, isolation casing, and hydro-sound dampers. The third approach is to eliminate the overlap of underwater waves by using prolonged construction process. To investigate the effectiveness of different noise mitigation methods; a pile driven with 235 kJ rated energy diesel hammer near Jeddah Coast, Kingdom of Saudi Arabia was used. Using empirical sound exposure model based on Red Sea characteristics and limits of National Oceanic and Atmospheric Administration; it was found that the aversive sound waves should extend to 1.8 km around the pile location. Bubble curtains can reduce the behavioral disturbance area up to 28%; temporary threshold shift up to 36%; permanent threshold shift up to 50%; and physical injury up to 70%. Isolation casing can reduce the behavioral disturbance range up to 12%; temporary threshold shift up to 21%; permanent threshold shift up to 29%; and physical injury up to 46%. Hydro-sound dampers efficiency depends mainly on the used technology and it can reduce the behavioral disturbance range from 10% to 33%; temporary threshold shift from 18% to 25%; permanent threshold shift from 32% to 50%; and physical injury from 46% to 60%. To prolong the construction process, it was found that the single pile construction, use of soft start, and keep time between two successive hammer strikes more than 3 seconds are the most effective techniques.

Keywords: offshore pile driving, sound propagation models, noise effects on marine mammals, Underwater noise mitigation

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1721 Study and Evaluation of Occupational Health and Safety in Power Plant in Pakistan

Authors: Saira Iqbal

Abstract:

Occupational Health and Safety issues nowadays have become an important esteem in the context of Industrial Production. This study is designed to measure the workplace hazards at Kohinoor Energy Limited. Mainly focused hazards were Heat Stress, Noise Level, Light Level and Ergonomics. Measurements for parameters like Wet, Dry, Globe, WBGTi and RH% were taken directly by visiting the Study Area. The temperature in Degrees was recoded at Control Room and Engine Hall. Highest Temperature was recoded in Engine Hall which was about 380C. Efforts were made to record emissions of Noise Levels from the main area of concern like Engines in Engine hall, parking area, and mechanical workshop. Permissible level for measuring Noise is 85 and its Unit of Measurement is dB (A). In Engine Hall Noise was very high which was about 109.6 dB (A) and that level was exceeding the limits. Illumination Level was also recorded at different areas of Power Plant. The light level was though under permissible limits but in some areas like Engine Hall and Boiler Room, level of light was very low especially in Engine Hall where the level was 29 lx. Practices were performed for measuring hazards in context of ergonomics like extended reaching, deviated body postures, mechanical stress, and vibration exposures of the worker at different units of plants by just observing workers during working hours. Since KEL is ISO 8000 and 14000 certified, the researcher found no serious problems in the parameter Ergonomics however it was a common scenario that workers were reluctant to apply PPEs.

Keywords: workplace hazards, heat hazard, noise hazard, illumination, ergonomics

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1720 Stroke Rehabilitation via Electroencephalogram Sensors and an Articulated Robot

Authors: Winncy Du, Jeremy Nguyen, Harpinder Dhillon, Reinardus Justin Halim, Clayton Haske, Trent Hughes, Marissa Ortiz, Rozy Saini

Abstract:

Stroke often causes death or cerebro-vascular (CV) brain damage. Most patients with CV brain damage lost their motor control on their limbs. This paper focuses on developing a reliable, safe, and non-invasive EEG-based robot-assistant stroke rehabilitation system to help stroke survivors to rapidly restore their motor control functions for their limbs. An electroencephalogram (EEG) recording device (EPOC Headset) and was used to detect a patient’s brain activities. The EEG signals were then processed, classified, and interpreted to the motion intentions, and then converted to a series of robot motion commands. A six-axis articulated robot (AdeptSix 300) was employed to provide the intended motions based on these commends. To ensure the EEG device, the computer, and the robot can communicate to each other, an Arduino microcontroller is used to physically execute the programming codes to a series output pins’ status (HIGH or LOW). Then these “hardware” commends were sent to a 24 V relay to trigger the robot’s motion. A lookup table for various motion intensions and the associated EEG signal patterns were created (through training) and installed in the microcontroller. Thus, the motion intention can be direct determined by comparing the EEG patterns obtaibed from the patient with the look-up table’s EEG patterns; and the corresponding motion commends are sent to the robot to provide the intended motion without going through feature extraction and interpretation each time (a time-consuming process). For safety sake, an extender was designed and attached to the robot’s end effector to ensure the patient is beyond the robot’s workspace. The gripper is also designed to hold the patient’s limb. The test results of this rehabilitation system show that it can accurately interpret the patient’s motion intension and move the patient’s arm to the intended position.

Keywords: brain waves, EEG sensor, motion control, robot-assistant stroke rehabilitation

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1719 Cost Analysis of Hybrid Wind Energy Generating System Considering CO2 Emissions

Authors: M. A. Badr, M. N. El Kordy, A. N. Mohib, M. M. Ibrahim

Abstract:

The basic objective of the research is to study the effect of hybrid wind energy on the cost of generated electricity considering the cost of reduction CO2 emissions. The system consists of small wind turbine(s), storage battery bank and a diesel generator (W/D/B). Using an optimization software package, different system configurations are investigated to reach optimum configuration based on the net present cost (NPC) and cost of energy (COE) as economic optimization criteria. The cost of avoided CO2 is taken into consideration. The system is intended to supply the electrical load of a small community (gathering six families) in a remote Egyptian area. The investigated system is not connected to the electricity grid and may replace an existing conventional diesel powered electric supply system to reduce fuel consumption and CO2 emissions. The simulation results showed that W/D energy system is more economic than diesel alone. The estimated COE is 0.308$/kWh and extracting the cost of avoided CO2, the COE reached 0.226 $/kWh which is an external benefit of wind turbine, as there are no pollutant emissions through operational phase.

Keywords: hybrid wind turbine systems, remote areas electrification, simulation of hybrid energy systems, techno-economic study

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1718 Improving Medication Understanding, Use and Self-Efficacy among Stroke Patients: A Randomised Controlled Trial; Study Protocol

Authors: Jamunarani Appalasamy, Tha Kyi Kyi, Quek Kia Fatt, Joyce Pauline Joseph, Anuar Zaini M. Zain

Abstract:

Background: The Health Belief Theory had always been associated with chronic disease management. Various health behaviour concepts and perception branching from this Health Belief Theory had involved with medication understanding, use, and self-efficacy which directly link to medication adherence. In a previous quantitative and qualitative study, stroke patients in Malaysia were found to be strongly believing information obtained by various sources such as the internet and social communication. This action leads to lower perception of their stroke preventative medication benefit which in long-term creates non-adherence. Hence, this study intends to pilot an intervention which uses audio-visual concept incorporated with mHealth service to enhance learning and self-reflection among stroke patients to manage their disease. Methods/Design: Twenty patients will be allocated to a proposed intervention whereas another twenty patients are allocated to the usual treatment. The intervention involves a series of developed audio-visual videos sent via mobile phone which later await for responses and feedback from the receiver (patient) via SMS or recorded calls. The primary outcome would be the medication understanding, use and self-efficacy measured over two months pre and post intervention. Secondary outcome is measured from changes of blood parameters and other self-reported questionnaires. Discussion: This study shall also assess uptake/attrition, feasibility, and acceptability of this intervention. Trial Registration: NMRR-15-851-24737 (IIR)

Keywords: health belief, medication understanding, medication use, self-efficacy

Procedia PDF Downloads 186
1717 Voyage Analysis of a Marine Gas Turbine Engine Installed to Power and Propel an Ocean-Going Cruise Ship

Authors: Mathias U. Bonet, Pericles Pilidis, Georgios Doulgeris

Abstract:

A gas turbine-powered cruise Liner is scheduled to transport pilgrim passengers from Lagos-Nigeria to the Islamic port city of Jeddah in Saudi Arabia. Since the gas turbine is an air breathing machine, changes in the density and/or mass flow at the compressor inlet due to an encounter with variations in weather conditions induce negative effects on the performance of the power plant during the voyage. In practice, all deviations from the reference atmospheric conditions of 15 oC and 1.103 bar tend to affect the power output and other thermodynamic parameters of the gas turbine cycle. Therefore, this paper seeks to evaluate how a simple cycle marine gas turbine power plant would react under a variety of scenarios that may be encountered during a voyage as the ship sails across the Atlantic Ocean and the Mediterranean Sea before arriving at its designated port of discharge. It is also an assessment that focuses on the effect of varying aerodynamic and hydrodynamic conditions which deteriorate the efficient operation of the propulsion system due to an increase in resistance that results from some projected levels of the ship hull fouling. The investigated passenger ship is designed to run at a service speed of 22 knots and cover a distance of 5787 nautical miles. The performance evaluation consists of three separate voyages that cover a variety of weather conditions in winter, spring and summer seasons. Real-time daily temperatures and the sea states for the selected transit route were obtained and used to simulate the voyage under the aforementioned operating conditions. Changes in engine firing temperature, power output as well as the total fuel consumed per voyage including other performance variables were separately predicted under both calm and adverse weather conditions. The collated data were obtained online from the UK Meteorological Office as well as the UK Hydrographic Office websites, while adopting the Beaufort scale for determining the magnitude of sea waves resulting from rough weather situations. The simulation of the gas turbine performance and voyage analysis was effected through the use of an integrated Cranfield-University-developed computer code known as ‘Turbomatch’ and ‘Poseidon’. It is a project that is aimed at developing a method for predicting the off design behavior of the marine gas turbine when installed and operated as the main prime mover for both propulsion and powering of all other auxiliary services onboard a passenger cruise liner. Furthermore, it is a techno-economic and environmental assessment that seeks to enable the forecast of the marine gas turbine part and full load performance as it relates to the fuel requirement for a complete voyage.

Keywords: cruise ship, gas turbine, hull fouling, performance, propulsion, weather

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1716 Detailed Sensitive Detection of Impurities in Waste Engine Oils Using Laser Induced Breakdown Spectroscopy, Rotating Disk Electrode Optical Emission Spectroscopy and Surface Plasmon Resonance

Authors: Cherry Dhiman, Ayushi Paliwal, Mohd. Shahid Khan, M. N. Reddy, Vinay Gupta, Monika Tomar

Abstract:

The laser based high resolution spectroscopic experimental techniques such as Laser Induced Breakdown Spectroscopy (LIBS), Rotating Disk Electrode Optical Emission spectroscopy (RDE-OES) and Surface Plasmon Resonance (SPR) have been used for the study of composition and degradation analysis of used engine oils. Engine oils are mainly composed of aliphatic and aromatics compounds and its soot contains hazardous components in the form of fine, coarse and ultrafine particles consisting of wear metal elements. Such coarse particulates matter (PM) and toxic elements are extremely dangerous for human health that can cause respiratory and genetic disorder in humans. The combustible soot from thermal power plants, industry, aircrafts, ships and vehicles can lead to the environmental and climate destabilization. It contributes towards global pollution for land, water, air and global warming for environment. The detection of such toxicants in the form of elemental analysis is a very serious issue for the waste material management of various organic, inorganic hydrocarbons and radioactive waste elements. In view of such important points, the current study on used engine oils was performed. The fundamental characterization of engine oils was conducted by measuring water content and kinematic viscosity test that proves the crude analysis of the degradation of used engine oils samples. The microscopic quantitative and qualitative analysis was presented by RDE-OES technique which confirms the presence of elemental impurities of Pb, Al, Cu, Si, Fe, Cr, Na and Ba lines for used waste engine oil samples in few ppm. The presence of such elemental impurities was confirmed by LIBS spectral analysis at various transition levels of atomic line. The recorded transition line of Pb confirms the maximum degradation which was found in used engine oil sample no. 3 and 4. Apart from the basic tests, the calculations for dielectric constants and refractive index of the engine oils were performed via SPR analysis.

Keywords: surface plasmon resonance, laser-induced breakdown spectroscopy, ICCD spectrometer, engine oil

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1715 Critical Evaluation of Long Chain Hydrocarbons with Biofuel Potential from Marine Diatoms Isolated from the West Coast of India

Authors: Indira K., Valsamma Joseph, I. S. Bright

Abstract:

Introduction :Biofuels could replace fossil fuels and reduce our carbon footprint on the planet by technological advancements needed for sustainable and economic fuel production. Micro algae have proven to be a promising source to meet the current energy demand because of high lipid content and production of high biomass rapidly. Marine diatoms, which are key contributors in the biofuel sector and also play a significant role in primary productivity and ecology with high biodiversity and genetic and chemical diversity, are less well understood than other microalgae for producing hydrocarbons. Method :The marine diatom samples selected for hydrocarbon analysis were a total of eleven, out of which 9 samples were from the culture collection of NCAAH, and the remaining two of them were isolated by serial dilution method to get a pure culture from a mixed culture of microalgae obtained from the various cruise stations (350&357) FORV Sagar Sampada along the west coast of India. These diatoms were mass cultured in F/2 media, and the biomass harvested. The crude extract was obtained from the biomass by homogenising with n-hexane, and the hydrocarbons was further obtained by passing the crude extract through 500mg Bonna Agela SPE column and the quantitative analysis was done by GCHRMS analysis using HP-5 column and Helium gas was used as a carrier gas(1ml/min). The injector port temperature was 2400C, the detector temperature was 2500C, and the oven was initially kept at 600C for 1 minute and increased to 2200C at the rate of 60C per minute, and the analysis of a mixture of long chain hydrocarbons was done .Results:In the qualitative analysis done, the most potent hydrocarbon was found to be Psammodictyon Panduriforme (NCAAH-9) with a hydrocarbon mass of 37.27mg/g of the biomass and 2.1% of the total biomass 0f 1.395g and the other potent producer is Biddulphia(NCAAH 6) with hydrocarbon mass of 25.4mg/g of biomass and percentage of hydrocarbon is 1.03%. In the quantitative analysis by GCHRMS, the long chain hydrocarbons found in most of the marine diatoms were undecane, hexadecane, octadecane 3ethyl 5,2 ethyl butyl, Eicosane7hexyl, hexacosane, heptacosane, heneicosane, octadecane 3 methyl, triacontane. The exact mass of the long chain hydrocarbons in all the marine diatom samples was found to be Nonadecane 12C191H40, Tritriacontane,13-decyl-13-heptyl 12C501H102, Octadecane,3ethyl-5-(2-ethylbutyl 12C261H54, tetratetracontane 12C441H89, Eicosane, 7-hexyl 12C261H54. Conclusion:All the marine diatoms screened produced long chain hydrocarbons which can be used as diesel fuel with good cetane value example, hexadecane, undecane. All the long chain hydrocarbons can further undergo catalytic cracking to produce short chain alkanes which can give good octane values and can be used as gasoline. Optimisation of hydrocarbon production with the most potent marine diatom yielded long chain hydrocarbons of good fuel quality.

Keywords: biofuel, hydrocarbons, marine diatoms, screening

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1714 Screening for Antibacterial Activity of Fungi from Indian Marine Environments: A Possible Alternative for New Antibiotics for the Treatment of Skin Microbial Infections

Authors: Shivankar Agrawal, Sunil Kumar Deshmukh, Colin Barrow, Alok Adholeya

Abstract:

Millions of people worldwide are affected by infectious diseases caused by bacteria and fungi. Skin and skin structure infections (SSSI) represent a significant category of infectious disease. Unexpectedly, many pathogens have developed resistance towards current antibiotics and over the time this problem has become more and more serious. All these new problems necessitate the continuous search for novel and alternative antibiotics and antifungals. The aim of our research is the screening of extracts of marine fungi for their antibacterial activity against bacteria causing skin and wound infection in humans. A total of 40 marine samples were collected from west coast and Andaman Island of India and 35 morphologically different marine fungi were isolated using natural sea water medium. Among 35 marine fungi, eight isolates exhibited significant antimicrobial activity against human pathogens. In the course of systematic screening program for bioactive marine fungi, strain 'D5' was found to be most potent strain with MIC value of 1 mg/mL, which was morphologically identified as Simplicillium lamellicola. The effects of the most active crude extracts against their susceptible test microorganisms were also investigated by SEM analysis. Purification and characterization of crude extracts for identification of active lead molecule is under process. The results of diversity and antimicrobial activity have increased the scope of finding industrially important marine fungi from Indian marine environments and these organisms could be vital sources for the discovery of pharmaceutically useful molecules.

Keywords: antimicrobial activity, antibiotic, marine fungi, skin infections

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1713 Preliminary Design of an Aerodynamic Protection for the Scramjet Engine Inlet of the Brazilian Technological Demonstrator Scramjet 14-X S

Authors: Gustavo J. Costa, Felipe J. Costa, Bruno L. Coelho, Ronaldo L. Cardoso, Rafael O. Santos, Israel S. Rêgo, Marco A. S. Minucci, Antonio C. Oliveira, Paulo G. P. Toro

Abstract:

The Prof. Henry T. Nagamatsu Aerothermodynamics and Hipersonics Laboratory, of the Institute for Advanced Studies (IEAv) conducts research and development (R&D) of the Technological Demonstrator scramjet 14-X S, aiming atmospheric flight at 30 km altitude with the speed correspondent to Mach number 7, using scramjet technology providing hypersonic propulsion system based on supersonic combustion. Hypersonic aerospace vehicles with air-breathing supersonic propulsion system face extremal environments for super/hypersonic flights in terms of thermal and aerodynamic loads. Thus, it is necessary to use aerodynamic protection at the scramjet engine inlet to face the thermal and aerodynamic loads without compromising the efficiency of scramjet engine, taking into account: i) inlet design (boundary layer, oblique shockwave and reflected oblique shockwave); ii) wall temperature of the cowl and of the compression ramp; iii) supersonic flow into the combustion chamber. The aerodynamic protection of the scramjet engine inlet will act to prevent the engine unstart and match the predictions made by theoretical-analytical, numerical analysis and experimental research, during the atmospheric flight of the Technological Demonstrator scramjet 14-X S.

Keywords: 14-X, hypersonic, scramjet, supersonic combustion

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1712 Research on Steam Injection Technology of Extended Range Engine Cylinder for Waste Heat Recovery

Authors: Zhiyuan Jia, Xiuxiu Sun, Yong Chen, Liu Hai, Shuangqing Li

Abstract:

The engine cooling water and exhaust gas contain a large amount of available energy. In order to improve energy efficiency, a steam injection technology based on waste heat recovery is proposed. The models of cooling water waste heat utilization, exhaust gas waste heat utilization, and exhaust gas-cooling water waste heat utilization were constructed, and the effects of the three modes on the performance of steam injection were analyzed, and then the feasibility of in-cylinder water injection steam technology based on waste heat recovery was verified. The research results show that when the injection water flow rate is 0.10 kg/s and the temperature is 298 K, at a cooling water temperature of 363 K, the maximum temperature of the injection water heated by the cooling water can reach 314.5 K; at an exhaust gas temperature of 973 K and an exhaust gas flow rate of 0.12 kg/s, the maximum temperature of the injection water heated by the exhaust gas can reach 430 K; Under the condition of cooling water temperature of 363 K, exhaust gas temperature of 973 K and exhaust gas flow rate of 0.12 kg/s, after cooling water and exhaust gas heating, the maximum temperature of the injection water can reach 463 K. When the engine is 1200 rpm, the water injection volume is 30 mg, and the water injection time is 36°CA, the engine power increases by 2% and the fuel consumption is reduced by 2.6%.

Keywords: cooling water, exhaust gas, extended range engine, steam injection, waste heat recovery

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1711 Optimizing Availability of Marine Knowledge Repository with Cloud-Based Framework

Authors: Ahmad S. Mohd Noor, Emma A. Sirajudin, Nur F. Mat Zain

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Reliability is an important property for knowledge repository system. National Marine Bioinformatics System or NABTICS is a marine knowledge repository portal aimed to provide a baseline for marine biodiversity and a tool for researchers and developers. It is intended to be a large and growing online database and also a metadata system for inputs of research analysis. The trends of present large distributed systems such as Cloud computing are the delivery of computing as a service rather than a product. The goal of this research is to make NABTICS a system of greater availability by integrating it with Cloud based Neighbor Replication and Failure Recovery (NRFR). This can be achieved by implementation of NABTICS into distributed environment. As a result, the user can experience minimum downtime while using the system should the server is having a failure. Consequently the online database application is said to be highly available.

Keywords: cloud, availability, distributed system, marine repository, database replication

Procedia PDF Downloads 442
1710 Assessment of the Root Causes of Marine Debris Problem in Lagos State

Authors: Chibuzo Okoye Daniels, Gillian Glegg, Lynda Rodwell

Abstract:

The continuously growing quantity of very slow degrading litter deliberately discarded into the coastal waters around Lagos as marine debris is obvious. What is not known is how to tackle this problem to reduce its prevalence and impact on the environment, economy and community. To identify ways of tackling the marine debris problem two case study areas (Ikoyi and Victoria Islands of Lagos State) were used to assess the root causes, the threat posed by marine debris in the coastal waters around Lagos and the efficacy of current instruments, programmes and initiatives that address marine debris in the study areas. The following methods were used: (1) Self-completed questionnaires for households and businesses within the study areas; (2) Semi-structured interviews with key stakeholders; (3) Observational studies of waste management from collection to disposal and waste management facilities for waste originating from land and maritime sources; (4) Beach surveys and marine debris surveys on shorelines and ports; and (5) Fishing for marine debris. Results of this study identified the following root causes: (1) Indiscriminate human activities and behaviors, and lack of awareness on the part of the main stakeholders and the public of the potential consequences of their actions; (2) Poor solid waste management practices; (3) Lack of strict legal frameworks addressing waste and marine debris problem; and (4) Disposal of non-degradable wastes into domestic sewer system and open streets drains. To effectively tackle marine debris problem in the study areas, adequate, appropriate and cost effective solutions to the above mentioned root causes needs to be identified and effectively transferred for implementation in the study areas.

Keywords: marine debris problem, Lagos state, litter, coastal waters

Procedia PDF Downloads 343
1709 Effect of Nitrogen-Based Cryotherapy on the Calf Muscle Spasticity in Stroke Patients

Authors: Engi E. I. Sarhan, Usama M. Rashad, Ibrahim M. I. Hamoda, Mohammed K. Mohamed

Abstract:

Background: This study aimed to know the effect of nitrogen-based cryotherapy on the spasticity of calf muscle in stroke patients. Patients were selected from the outpatient clinic of Neurology, Al-Mansoura general hospital, Al-Mansoura University. Subjects and methods: Thirty Stroke Patients of both sexes ranged from 45 to 60 years old were divided randomly into two equal groups, a study group (A) received a nitrogen-based cryotherapy, a selective physical therapy program and ankle foot orthosis (AFO), while as patients in control group (B) received the same program and AFO only. The treatment duration was three times per week for four weeks for both groups. We assessed spasticity of calf muscle before and after treatment subjectively using modified Ashworth scale (MAS) and objectively via measuring H / M ratio on electromyography machine. We also assessed ankle dorsiflexion ROM objectively using two dimensions motion analysis (2D). Results: After treatment, there was a highly significant improvement in the study group compared to the control group regarding the score of MAS, no significant difference in the study group compared to the control group regarding the readings of H / M ratio, highly significant improvement in the study group compared to the control group regarding the 2D motion analysis findings. Conclusion: This modality considers effective in reducing spasticity in the calf muscle and improving ankle dorsiflexion of the affected limb.

Keywords: ankle foot orthosis, nitrogen-based cryotherapy, stroke, spasticity

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1708 Marine Litter and Microplastic Pollution in Mangrove Sediments in The Sea of Oman

Authors: Muna Al-Tarshi, Dobretsov Sergey, Wenresti Gallardo

Abstract:

Marine litter pollution is a global concern that has wide-ranging ecological, societal, and economic implications, along with potential health risks for humans. In Oman, inadequate solid waste management has led to the accumulation of litter in mangrove ecosystems. However, there is a dearth of information on marine litter and microplastic pollution in Omani mangroves, impeding the formulation of effective mitigation strategies. To address this knowledge gap, we conducted a comprehensive assessment of marine litter and microplastics in mangrove sediments in the Sea of Oman. Our study measured the average abundance of marine litter, which ranged from 0.83±1.03 to 19.42±8.52 items/m2. Notably, plastics constituted the majority of litter, accounting for 73-96% of all items, with soft plastics being the most prevalent. Furthermore, we investigated microplastic concentrations in the sediments, finding levels ranging from 6 to 256 pieces /kg. Among the studied areas, afforested mangroves in Al-Sawadi exhibited the highest average abundance of microplastics (27.52±5.32 pieces/ kg), while the Marine Protected Area Al Qurum had the lowest average abundance (0.60±1.12 pieces /kg). These findings significantly contribute to our understanding of marine litter and microplastic pollution in Omani mangroves. They provide valuable baseline data for future monitoring initiatives and the development of targeted management strategies. Urgent action is needed to implement effective waste management practices and interventions to protect the ecological integrity of mangrove ecosystems in Oman and mitigate the risks associated with marine litter and microplastics.

Keywords: microplastics, anthropogenic marine litter, ftir, polymer, khawr, mangrove, sediment

Procedia PDF Downloads 58
1707 A Top-down vs a Bottom-up Approach on Lower Extremity Motor Recovery and Balance Following Acute Stroke: A Randomized Clinical Trial

Authors: Vijaya Kumar, Vidayasagar Pagilla, Abraham Joshua, Rakshith Kedambadi, Prasanna Mithra

Abstract:

Background: Post stroke rehabilitation are aimed to accelerate for optimal sensorimotor recovery, functional gain and to reduce long-term dependency. Intensive physical therapy interventions can enhance this recovery as experience-dependent neural plastic changes either directly act at cortical neural networks or at distal peripheral level (muscular components). Neuromuscular Electrical Stimulation (NMES), a traditional bottom-up approach, mirror therapy (MT), a relatively new top down approach have found to be an effective adjuvant treatment methods for lower extremity motor and functional recovery in stroke rehabilitation. However there is a scarcity of evidence to compare their therapeutic gain in stroke recovery.Aim: To compare the efficacy of neuromuscular electrical stimulation (NMES) and mirror therapy (MT) in very early phase of post stroke rehabilitation addressed to lower extremity motor recovery and balance. Design: observer blinded Randomized Clinical Trial. Setting: Neurorehabilitation Unit, Department of Physical Therapy, Tertiary Care Hospitals. Subjects: 32 acute stroke subjects with first episode of unilateral stroke with hemiparesis, referred for rehabilitation (onset < 3 weeks), Brunnstorm lower extremity recovery stages ≥3 and MMSE score more than 24 were randomized into two group [Group A-NMES and Group B-MT]. Interventions: Both the groups received eclectic approach to remediate lower extremity recovery which includes treatment components of Roods, Bobath and Motor learning approaches for 30 minutes a day for 6 days. Following which Group A (N=16) received 30 minutes of surface NMES training for six major paretic muscle groups (gluteus maximus and medius,quadriceps, hamstrings, tibialis anterior and gastrocnemius). Group B (N=16) was administered with 30 minutes of mirror therapy sessions to facilitate lower extremity motor recovery. Outcome measures: Lower extremity motor recovery, balance and activities of daily life (ADLs) were measured by Fugyl Meyer Assessment (FMA-LE), Berg Balance Scale (BBS), Barthel Index (BI) before and after intervention. Results: Pre Post analysis of either group across the time revealed statistically significant improvement (p < 0.001) for all the outcome variables for the either group. All parameters of NMES had greater change scores compared to MT group as follows: FMA-LE (25.12±3.01 vs. 23.31±2.38), BBS (35.12±4.61 vs. 34.68±5.42) and BI (40.00±10.32 vs. 37.18±7.73). Between the groups comparison of pre post values showed no significance with FMA-LE (p=0.09), BBS (p=0.80) and BI (p=0.39) respectively. Conclusion: Though either groups had significant improvement (pre to post intervention), none of them were superior to other in lower extremity motor recovery and balance among acute stroke subjects. We conclude that eclectic approach is an effective treatment irrespective of NMES or MT as an adjunct.

Keywords: balance, motor recovery, mirror therapy, neuromuscular electrical stimulation, stroke

Procedia PDF Downloads 256
1706 Optimization of Slider Crank Mechanism Using Design of Experiments and Multi-Linear Regression

Authors: Galal Elkobrosy, Amr M. Abdelrazek, Bassuny M. Elsouhily, Mohamed E. Khidr

Abstract:

Crank shaft length, connecting rod length, crank angle, engine rpm, cylinder bore, mass of piston and compression ratio are the inputs that can control the performance of the slider crank mechanism and then its efficiency. Several combinations of these seven inputs are used and compared. The throughput engine torque predicted by the simulation is analyzed through two different regression models, with and without interaction terms, developed according to multi-linear regression using LU decomposition to solve system of algebraic equations. These models are validated. A regression model in seven inputs including their interaction terms lowered the polynomial degree from 3rd degree to 1st degree and suggested valid predictions and stable explanations.

Keywords: design of experiments, regression analysis, SI engine, statistical modeling

Procedia PDF Downloads 154
1705 Effect of Halo Protection Device on the Aerodynamic Performance of Formula Racecar

Authors: Mark Lin, Periklis Papadopoulos

Abstract:

This paper explores the aerodynamics of the formula racecar when a ‘halo’ driver-protection device is added to the chassis. The halo protection device was introduced at the start of the 2018 racing season as a safety measure against foreign object impacts that a driver may encounter when driving an open-wheel racecar. In the one-year since its introduction, the device has received wide acclaim for protecting the driver on two separate occasions. The benefit of such a safety device certainly cannot be disputed. However, by adding the halo device to a car, it changes the airflow around the vehicle, and most notably, to the engine air-intake and the rear wing. These negative effects in the air supply to the engine, and equally to the downforce created by the rear wing are studied in this paper using numerical technique, and the resulting CFD outputs are presented and discussed. Comparing racecar design prior to and after the introduction of the halo device, it is shown that the design of the air intake and the rear wing has not followed suit since the addition of the halo device. The reduction of engine intake mass flow due to the halo device is computed and presented for various speeds the car may be going. Because of the location of the halo device in relation to the air intake, airflow is directed away from the engine, making the engine perform less than optimal. The reduction is quantified in this paper to show the correspondence to reduce the engine output when compared to a similar car without the halo device. This paper shows that through aerodynamic arguments, the engine in a halo car will not receive unobstructed, clean airflow that a non-halo car does. Another negative effect is on the downforce created by the rear wing. Because the amount of downforce created by the rear wing is influenced by every component that comes before it, when a halo device is added upstream to the rear wing, airflow is obstructed, and less is available for making downforce. This reduction in downforce is especially dramatic as the speed is increased. This paper presents a graph of downforce over a range of speeds for a car with and without the halo device. Acknowledging that although driver safety is paramount, the negative effect of this safety device on the performance of the car should still be well understood so that any possible redesign to mitigate these negative effects can be taken into account in next year’s rules regulation.

Keywords: automotive aerodynamics, halo device, downforce. engine intake

Procedia PDF Downloads 80
1704 Catalytic Hydrothermal Decarboxylation of Lipid from Activated Sludge for Renewable Diesel Production

Authors: Ifeanyichukwu Edeh, Tim Overton, Steve Bowra

Abstract:

Currently biodiesel is produced from plant oils or animal’s fats by a liquid-phase catalysed transesterification process at low temperature. Although biodiesel is renewable and to a large extent sustainable, inherent properties such as poor cold flow, low oxidation stability, low cetane value restrict application to blends with fossil fuels. An alternative to biodiesel is renewable diesel produced by catalytic hydrotreating of oils and fats and is considered a drop in fuel because its properties are similar to petroleum diesel. In addition to developing alternative productions routes there is continued interest in reducing the cost of the feed stock, waste cooking oils and fats are increasingly used as the feedstocks due to low cost. However, use of oils and fat are highly adulterated resulting in high free fatty acid content which turn impacts on the efficiency of FAME production. Therefore, in light of the need to develop, alternative lipid feed stocks and related efficient catalysis the present study investigates the potential of producing renewable diesel from the lipids-extracted from activated sludge, a waste water treatment by-product, through catalytic hydrothermal decarboxylation. The microbial lipids were first extracted from the activated sludge using the Folch et al method before hydrothermal decarboxylation reactions were carried out using palladium (Pd/C) and platinum (Pt/C) on activated carbon as the catalysts in a batch reactor. The impact of three temperatures 290, 300, 330 °C and residence time between 30 min and 4hrs was assessed. At the end of the reaction, the products were recovered using organic solvents and characterized using gas chromatography (GC). The principle products of the reaction were pentadecane and heptadecane. The highest yields of pentadecane and heptadecane from lipid-extract were 23.23% and 15.21%, respectively. These yields were obtained at 290 °C and residence time 1h using Pt/C. To the best of our knowledge, the current work is the first investigation on the hydrothermal decarboxylation of lipid-extract from activated sludge.

Keywords: activated sludge, lipid, hydrothermal decarboxylation, renewable diesel

Procedia PDF Downloads 283
1703 A Study on Development Strategies of Marine Leisure Tourism Using AHP

Authors: Da-Hye Jang, Woo-Jeong Cho

Abstract:

Marine leisure tourism contributes greatly to the national economy in which the sea is located nearby and many countries are using marine tourism to create value added. The interest and investment of government and local governments on marine leisure tourism growing as a major trend of marine tourism is steadily increasing. But indiscriminate investment in marine leisure tourism such as duplicated business wastes limited resources. In other words, government and local governments need to select and concentrate on the goal they pursue by drawing priority on maritime leisure tourism policies. The purpose of this study is to analyze development strategies on supplier for marine leisure tourism and thus provide a comprehensive and rational framework for developing marine leisure tourism. In order to achieve the purpose, this study is to analyze priorities for each evaluation criterion of marine leisure tourism development policies using Analytic Hierarchy Process. In this study, a questionnaire was used as the survey tool and was developed based on the previous studies, government report, regional report, related thesis and literature for marine leisure tourism. The questionnaire was constructed by verifying the validity of contents from the expert group related to marine leisure tourism after conducting the first and second preliminary surveys. The AHP survey was conducted to experts (university professors, researchers, field specialists and related public officials) from April 6, 2018 to April 30, 2018 by visiting in person or e-mail. This study distributed 123 questionnaires and 68 valid questionnaires were used for data analysis. As a result, 4 factors with 12 detail strategies were analyzed using Excel. Extracted factors of development strategies of marine leisure tourism are consist of 4 factors such as infrastructure, popularization, law & system improvement and advancement. In conclusion, the results of the pairwise comparison of the four major factor on the first class were infrastructure, popularization, law & system improvement and advancement in order. Second, marine water front space maintenance had higher priority than marina facilities expansion and the establishment of marine leisure education center. Third, marine leisure safety·culture improvement had higher priority than strengthening experience·education program and the upkeep and open promotion event. Fourth, specialization·cluster of marine leisure tourism had higher priority than business support system of marine leisure tourism. Fifth, the revision of water-related leisure activities safety act had higher priority than an enactment of marine tourism promotion act and the foster of marina service industry. Finally, marine water front space maintenance was the most important development plan to boost marine leisure tourism.

Keywords: marine leisure tourism, marine leisure, marine tourism, analytic hierarchy process

Procedia PDF Downloads 131
1702 Biodiesel Production from Fruit Pulp of Cassia fistula L. Using Green Microalga Chlorella minutissima

Authors: Rajesh Chandra, Uttam K. Ghosh

Abstract:

This study demonstrates microalgal bio-diesel generation from a cheap, abundant, non-edible fruit pulp of Cassia fistula L. The Cassia fistula L. fruit pulp aqueous extract (CFAE) was utilized as a growth medium for cultivation of microalga Chlorella minutissima (C. minutissima). This microalga accumulated a high amount of lipids when cultivated with CFAE as a source of nutrition in comparison to BG-11 medium. Different concentrations (10, 20, 30, 40 and 50%) of CFAE diluted with distilled water were used to cultivate microalga. Effects of light intensity and photoperiod were also observed on biomass and lipid yield of microalga. Light intensity of 8000 lux with a photoperiod of 18 h resulted in maximum biomass and lipid yield of 1.28 ± 0.03 and 0.3968 ± 0.05 g/L, respectively when cultivated with 40% CFAE. Fatty acid methyl ester (FAME) profile of bio-diesel obtained shown the presence of myristic acid (C14:0), palmitic acid (C16:0), palmitoleic acid (C16:1), stearic acid (C18:0), linoleic acid (C18:2), linolenic acid (C18:3), arachidic acid (C20:0), and gondoic acid (C20:1), as major fatty acids. These facts reflect that the fruit pulp of Cassia fistula L. can be used for cultivation of C. minutissima.

Keywords: biomass, bio-diesel, Cassia fistula L., C. minutissima, GC-MS, lipid

Procedia PDF Downloads 128
1701 Numerical Studies on Bypass Thrust Augmentation Using Convective Heat Transfer in Turbofan Engine

Authors: R. Adwaith, J. Gopinath, Vasantha Kohila B., R. Chandru, Arul Prakash R.

Abstract:

The turbofan engine is a type of air breathing engine that is widely used in aircraft propulsion produces thrust mainly from the mass-flow of air bypassing the engine core. The present research has developed an effective method numerically by increasing the thrust generated from the bypass air. This thrust increase is brought about by heating the walls of the bypass valve from the combustion chamber using convective heat transfer method. It is achieved computationally by the use external heat to enhance the velocity of bypass air of turbofan engines. The bypass valves are either heated externally using multicell tube resistor which convert electricity generated by dynamos into heat or heat is transferred from the combustion chamber. This increases the temperature of the flow in the valves and thereby increase the velocity of the flow that enters the nozzle of the engine. As a result, mass-flow of air passing the core engine for producing more thrust can be significantly reduced thereby saving considerable amount of Jet fuel. Numerical analysis has been carried out on a scaled down version of a typical turbofan bypass valve, where the valve wall temperature has been increased to 700 Kelvin. It is observed from the analysis that, the exit velocity contributing to thrust has significantly increased by 10 % due to the heating of by-pass valve. The degree of optimum increase in the temperature, and the corresponding effect in the increase of jet velocity is calculated to determine the operating temperature range for efficient increase in velocity. The technique used in the research increases the thrust by using heated by-pass air without extracting much work from the fuel and thus improve the efficiency of existing turbofan engines. Dimensional analysis has been carried to prove the accuracy of the results obtained numerically.

Keywords: turbofan engine, bypass valve, multi-cell tube, convective heat transfer, thrust

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1700 NOx Prediction by Quasi-Dimensional Combustion Model of Hydrogen Enriched Compressed Natural Gas Engine

Authors: Anas Rao, Hao Duan, Fanhua Ma

Abstract:

The dependency on the fossil fuels can be minimized by using the hydrogen enriched compressed natural gas (HCNG) in the transportation vehicles. However, the NOx emissions of HCNG engines are significantly higher, and this turned to be its major drawback. Therefore, the study of NOx emission of HCNG engines is a very important area of research. In this context, the experiments have been performed at the different hydrogen percentage, ignition timing, air-fuel ratio, manifold-absolute pressure, load and engine speed. Afterwards, the simulation has been accomplished by the quasi-dimensional combustion model of HCNG engine. In order to investigate the NOx emission, the NO mechanism has been coupled to the quasi-dimensional combustion model of HCNG engine. The three NOx mechanism: the thermal NOx, prompt NOx and N2O mechanism have been used to predict NOx emission. For the validation purpose, NO curve has been transformed into NO packets based on the temperature difference of 100 K for the lean-burn and 60 K for stoichiometric condition. While, the width of the packet has been taken as the ratio of crank duration of the packet to the total burnt duration. The combustion chamber of the engine has been divided into three zones, with the zone equal to the product of summation of NO packets and space. In order to check the accuracy of the model, the percentage error of NOx emission has been evaluated, and it lies in the range of ±6% and ±10% for the lean-burn and stoichiometric conditions respectively. Finally, the percentage contribution of each NO formation has been evaluated.

Keywords: quasi-dimensional combustion , thermal NO, prompt NO, NO packet

Procedia PDF Downloads 223