Search results for: energy efficiency measures
1432 The Use of Non-Parametric Bootstrap in Computing of Microbial Risk Assessment from Lettuce Consumption Irrigated with Contaminated Water by Sanitary Sewage in Infulene Valley
Authors: Mario Tauzene Afonso Matangue, Ivan Andres Sanchez Ortiz
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The Metropolitan area of Maputo (Mozambique Capital City) is located in semi-arid zone (800 mm annual rainfall) with 1101170 million inhabitants. On the west side, there are the flatlands of Infulene where the Mulauze River flows towards to the Indian Ocean, receiving at this site, the storm water contaminated with sanitary sewage from Maputo, transported through a concrete open channel. In Infulene, local communities grow salads crops such as tomato, onion, garlic, lettuce, and cabbage, which are then commercialized and consumed in several markets in Maputo City. Lettuce is the most daily consumed salad crop in different meals, generally in fast-foods, breakfasts, lunches, and dinners. However, the risk of infection by several pathogens due to the consumption of lettuce, using the Quantitative Microbial Risk Assessment (QMRA) tools, is still unknown since there are few studies or publications concerning to this matter in Mozambique. This work is aimed at determining the annual risk arising from the consumption of lettuce grown in Infulene valley, in Maputo, using QMRA tools. The exposure model was constructed upon the volume of contaminated water remaining in the lettuce leaves, the empirical relations between the number of pathogens and the indicator of microorganisms (E. coli), the consumption of lettuce (g) and reduction of pathogens (days). The reference pathogens were Vibrio cholerae, Cryptosporidium, norovirus, and Ascaris. The water quality samples (E. coli) were collected in the storm water channel from January 2016 to December 2018, comprising 65 samples, and the urban lettuce consumption data were collected through inquiry in Maputo Metropolis covering 350 persons. A non-parametric bootstrap was performed involving 10,000 iterations over the collected dataset, namely, water quality (E. coli) and lettuce consumption. The dose-response models were: Exponential for Cryptosporidium, Kummer Confluent hypergeomtric function (1F1) for Vibrio and Ascaris Gaussian hypergeometric function (2F1-(a,b;c;z) for norovirus. The annual infection risk estimates were performed using R 3.6.0 (CoreTeam) software by Monte Carlo (Latin hypercubes), a sampling technique involving 10,000 iterations. The annual infection risks values expressed by Median and the 95th percentile, per person per year (pppy) arising from the consumption of lettuce are as follows: Vibrio cholerae (1.00, 1.00), Cryptosporidium (3.91x10⁻³, 9.72x 10⁻³), nororvirus (5.22x10⁻¹, 9.99x10⁻¹) and Ascaris (2.59x10⁻¹, 9.65x10⁻¹). Thus, the consumption of the lettuce would result in greater risks than the tolerable levels ( < 10⁻³ pppy or 10⁻⁶ DALY) for all pathogens, and the Vibrio cholerae is the most virulent pathogens, according to the hit-single models followed by the Ascaris lumbricoides and norovirus. The sensitivity analysis carried out in this work pointed out that in the whole QMRA, the most important input variable was the reduction of pathogens (Spearman rank value was 0.69) between harvest and consumption followed by water quality (Spearman rank value was 0.69). The decision-makers (Mozambique Government) must strengthen the prevention measures related to pathogens reduction in lettuce (i.e., washing) and engage in wastewater treatment engineering.Keywords: annual infections risk, lettuce, non-parametric bootstrapping, quantitative microbial risk assessment tools
Procedia PDF Downloads 1241431 Transformation of Hexagonal Cells into Auxetic in Core Honeycomb Furniture Panels
Authors: Jerzy Smardzewski
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Structures with negative Poisson's ratios are called auxetic. They are characterized by better mechanical properties than conventional structures, especially shear strength, the ability to better absorb energy and increase strength during bending, especially in sandwich panels. Commonly used paper cores of cellular boards are made of hexagonal cells. With isotropic facings, these cells provide isotropic properties of the entire furniture board. Shelves made of such panels with a thickness similar to standard chipboards do not provide adequate stiffness and strength of the furniture. However, it is possible to transform the shape of hexagonal cells into polyhedral auxetic cells that improve the mechanical properties of the core. The work aimed to transform the hexagonal cells of the paper core into auxetic cells and determine their basic mechanical properties. Using numerical methods, it was decided to design the most favorable proportions of cells distinguished by the lowest Poisson's ratio and the highest modulus of linear elasticity. Standard cores for cellular boards commonly used to produce 34 mm thick furniture boards were used for the tests. Poisson's ratios, bending strength, and linear elasticity moduli were determined for such cores and boards. Then, the cells were transformed into auxetic structures, and analogous cellular boards were made for which mechanical properties were determined. The results of numerical simulations for which the variable parameters were the dimensions of the cell walls, wall inclination angles, and relative cell density were presented in the further part of the paper. Experimental tests and numerical simulations showed the beneficial effect of auxeticization on the mechanical quality of furniture panels. They allowed for the selection of the optimal shape of auxetic core cells.Keywords: auxetics, honeycomb, panels, simulation, experiment
Procedia PDF Downloads 161430 Modeling and Design of E-mode GaN High Electron Mobility Transistors
Authors: Samson Mil'shtein, Dhawal Asthana, Benjamin Sullivan
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The wide energy gap of GaN is the major parameter justifying the design and fabrication of high-power electronic components made of this material. However, the existence of a piezo-electrics in nature sheet charge at the AlGaN/GaN interface complicates the control of carrier injection into the intrinsic channel of GaN HEMTs (High Electron Mobility Transistors). As a result, most of the transistors created as R&D prototypes and all of the designs used for mass production are D-mode devices which introduce challenges in the design of integrated circuits. This research presents the design and modeling of an E-mode GaN HEMT with a very low turn-on voltage. The proposed device includes two critical elements allowing the transistor to achieve zero conductance across the channel when Vg = 0V. This is accomplished through the inclusion of an extremely thin, 2.5nm intrinsic Ga₀.₇₄Al₀.₂₆N spacer layer. The added spacer layer does not create piezoelectric strain but rather elastically follows the variations of the crystal structure of the adjacent GaN channel. The second important factor is the design of a gate metal with a high work function. The use of a metal gate with a work function (Ni in this research) greater than 5.3eV positioned on top of n-type doped (Nd=10¹⁷cm⁻³) Ga₀.₇₄Al₀.₂₆N creates the necessary built-in potential, which controls the injection of electrons into the intrinsic channel as the gate voltage is increased. The 5µm long transistor with a 0.18µm long gate and a channel width of 30µm operate at Vd=10V. At Vg =1V, the device reaches the maximum drain current of 0.6mA, which indicates a high current density. The presented device is operational at frequencies greater than 10GHz and exhibits a stable transconductance over the full range of operational gate voltages.Keywords: compound semiconductors, device modeling, enhancement mode HEMT, gallium nitride
Procedia PDF Downloads 2641429 Permeable Bio-Reactive Barriers to Tackle Petroleum Hydrocarbon Contamination in the Sub-Antarctic
Authors: Benjamin L. Freidman, Sally L. Gras, Ian Snape, Geoff W. Stevens, Kathryn A. Mumford
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Increasing transportation and storage of petroleum hydrocarbons in Antarctic and sub-Antarctic regions have resulted in frequent accidental spills. Migrating petroleum hydrocarbon spills can have a significant impact on terrestrial and marine ecosystems in cold regions, as harsh environmental conditions result in heightened sensitivity to pollution. This migration of contaminants has led to the development of Permeable Reactive Barriers (PRB) for application in cold regions. PRB’s are one of the most practical technologies for on-site or in-situ groundwater remediation in cold regions due to their minimal energy, monitoring and maintenance requirements. The Main Power House site has been used as a fuel storage and power generation area for the Macquarie Island research station since at least 1960. Soil analysis at the site has revealed Total Petroleum Hydrocarbon (TPH) (C9-C28) concentrations as high as 19,000 mg/kg soil. Groundwater TPH concentrations at this site can exceed 350 mg/L TPH. Ongoing migration of petroleum hydrocarbons into the neighbouring marine ecosystem resulted in the installation of a ‘funnel and gate’ PRB in November 2014. The ‘funnel and gate’ design successfully intercepted contaminated groundwater and analysis of TPH retention and biodegradation on PRB media are currently underway. Installation of the PRB facilitates research aimed at better understanding the contribution of particle attached biofilms to the remediation of groundwater systems. Bench-scale PRB system analysis at The University of Melbourne is currently examining the role biofilms play in petroleum hydrocarbon degradation, and how controlled release nutrient media can heighten the metabolic activity of biofilms in cold regions in the presence of low temperatures and low nutrient groundwater.Keywords: groundwater, petroleum, Macquarie island, funnel and gate
Procedia PDF Downloads 3631428 Process Improvement and Redesign of the Immuno Histology (IHC) Lab at MSKCC: A Lean and Ergonomic Study
Authors: Samantha Meyerholz
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MSKCC offers patients cutting edge cancer care with the highest quality standards. However, many patients and industry members do not realize that the operations of the Immunology Histology Lab (IHC) are the backbone for carrying out this mission. The IHC lab manufactures blocks and slides containing critical tissue samples that will be read by a Pathologist to diagnose and dictate a patient’s treatment course. The lab processes 200 requests daily, leading to the generation of approximately 2,000 slides and 1,100 blocks each day. Lab material is transported through labeling, cutting, staining and sorting manufacturing stations, while being managed by multiple techs throughout the space. The quality of the stain as well as wait times associated with processing requests, is directly associated with patients receiving rapid treatments and having a wider range of care options. This project aims to improve slide request turnaround time for rush and non-rush cases, while increasing the quality of each request filled (no missing slides or poorly stained items). Rush cases are to be filled in less than 24 hours, while standard cases are allotted a 48 hour time period. Reducing turnaround times enable patients to communicate sooner with their clinical team regarding their diagnosis, ultimately leading faster treatments and potentially better outcomes. Additional project goals included streamlining tech and material workflow, while reducing waste and increasing efficiency. This project followed a DMAIC structure with emphasis on lean and ergonomic principles that could be integrated into an evolving lab culture. Load times and batching processes were analyzed using process mapping, FMEA analysis, waste analysis, engineering observation, 5S and spaghetti diagramming. Reduction of lab technician movement as well as their body position at each workstation was of top concern to pathology leadership. With new equipment being brought into the lab to carry out workflow improvements, screen and tool placement was discussed with the techs in focus groups, to reduce variation and increase comfort throughout the workspace. 5S analysis was completed in two phases in the IHC lab, helping to drive solutions that reduced rework and tech motion. The IHC lab plans to continue utilizing these techniques to further reduce the time gap between tissue analysis and cancer care.Keywords: engineering, ergonomics, healthcare, lean
Procedia PDF Downloads 2251427 Diselenide-Linked Redox Stimuli-Responsive Methoxy Poly(Ethylene Glycol)-b-Poly(Lactide-Co-Glycolide) Micelles for the Delivery of Doxorubicin in Cancer Cells
Authors: Yihenew Simegniew Birhan, Hsieh Chih Tsai
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The recent advancements in synthetic chemistry and nanotechnology fostered the development of different nanocarriers for enhanced intracellular delivery of pharmaceutical agents to tumor cells. Polymeric micelles (PMs), characterized by small size, appreciable drug loading capacity (DLC), better accumulation in tumor tissue via enhanced permeability and retention (EPR) effect, and the ability to avoid detection and subsequent clearance by the mononuclear phagocyte (MNP) system, are convenient to improve the poor solubility, slow absorption and non-selective biodistribution of payloads embedded in their hydrophobic cores and hence, enhance the therapeutic efficacy of chemotherapeutic agents. Recently, redox-responsive polymeric micelles have gained significant attention for the delivery and controlled release of anticancer drugs in tumor cells. In this study, we synthesized redox-responsive diselenide bond containing amphiphilic polymer, Bi(mPEG-PLGA)-Se₂ from mPEG-PLGA, and 3,3'-diselanediyldipropanoic acid (DSeDPA) using DCC/DMAP as coupling agents. The successful synthesis of the copolymers was verified by different spectroscopic techniques. Above the critical micelle concentration, the amphiphilic copolymer, Bi(mPEG-PLGA)-Se₂, self-assembled into stable micelles. The DLS data indicated that the hydrodynamic diameter of the micelles (123.9 ± 0.85 nm) was suitable for extravasation into the tumor cells through the EPR effect. The drug loading content (DLC) and encapsulation efficiency (EE) of DOX-loaded micelles were found to be 6.61 wt% and 54.9%, respectively. The DOX-loaded micelles showed initial burst release accompanied by sustained release trend where 73.94% and 69.54% of encapsulated DOX was released upon treatment with 6mM GSH and 0.1% H₂O₂, respectively. The biocompatible nature of Bi(mPEG-PLGA)-Se₂ copolymer was confirmed by the cell viability study. In addition, the DOX-loaded micelles exhibited significant inhibition against HeLa cells (44.46%), at a maximum dose of 7.5 µg/mL. The fluorescent microscope images of HeLa cells treated with 3 µg/mL (equivalent DOX concentration) revealed efficient internalization and accumulation of DOX-loaded Bi(mPEG-PLGA)-Se₂ micelles in the cytosol of cancer cells. In conclusion, the intelligent, biocompatible, and the redox stimuli-responsive behavior of Bi(mPEG-PLGA)-Se₂ copolymer marked the potential applications of diselenide-linked mPEG-PLGA micelles for the delivery and on-demand release of chemotherapeutic agents in cancer cells.Keywords: anticancer drug delivery, diselenide bond, polymeric micelles, redox-responsive
Procedia PDF Downloads 1111426 FlameCens: Visualization of Expressive Deviations in Music Performance
Authors: Y. Trantafyllou, C. Alexandraki
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Music interpretation accounts to the way musicians shape their performance by deliberately deviating from composers’ intentions, which are commonly communicated via some form of music transcription, such as a music score. For transcribed and non-improvised music, music expression is manifested by introducing subtle deviations in tempo, dynamics and articulation during the evolution of performance. This paper presents an application, named FlameCens, which, given two recordings of the same piece of music, presumably performed by different musicians, allow visualising deviations in tempo and dynamics during playback. The application may also compare a certain performance to the music score of that piece (i.e. MIDI file), which may be thought of as an expression-neutral representation of that piece, hence depicting the expressive queues employed by certain performers. FlameCens uses the Dynamic Time Warping algorithm to compare two audio sequences, based on CENS (Chroma Energy distribution Normalized Statistics) audio features. Expressive deviations are illustrated in a moving flame, which is generated by an animation of particles. The length of the flame is mapped to deviations in dynamics, while the slope of the flame is mapped to tempo deviations so that faster tempo changes the slope to the right and slower tempo changes the slope to the left. Constant slope signifies no tempo deviation. The detected deviations in tempo and dynamics can be additionally recorded in a text file, which allows for offline investigation. Moreover, in the case of monophonic music, the color of particles is used to convey the pitch of the notes during performance. FlameCens has been implemented in Python and it is openly available via GitHub. The application has been experimentally validated for different music genres including classical, contemporary, jazz and popular music. These experiments revealed that FlameCens can be a valuable tool for music specialists (i.e. musicians or musicologists) to investigate the expressive performance strategies employed by different musicians, as well as for music audience to enhance their listening experience.Keywords: audio synchronization, computational music analysis, expressive music performance, information visualization
Procedia PDF Downloads 1331425 Adaptability of Steel-Framed Industrialized Building System
Authors: Alireza Taghdiri, Sara Ghanbarzade Ghomi
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Existing buildings are permanently subjected to change, continuously renovated and repaired in their long service life. Old buildings are destroyed and their material and components are recycled or reused for constructing new ones. In this process, importance of sustainability principles for building construction is obviously known and great significance must be attached to consumption of resources, resulting effects on the environment and economic costs. Utilization strategies for extending buildings service life and delay in destroying have positive effect on environment protection. In addition, simpler alterability or expandability of buildings’ structures and reducing energy and natural resources consumption have benefits for users, producers and environment. To solve these problems, by applying theories of open building, structural components of some conventional building systems have been analyzed and then, a new geometry adaptive building system is developed which can transform and support different imposed loads. In order to achieve this goal, various research methods and tools such as professional and scientific literatures review, comparative analysis, case study and computer simulation were applied and data interpretation was implemented using descriptive statistics and logical arguments. Therefore, hypothesis and proposed strategies were evaluated and an adaptable and reusable 2-dimensional building system was presented which can respond appropriately to dwellers and end-users needs and provide reusability of structural components of building system in new construction or function. Investigations showed that this incremental building system can be successfully applied in achieving the architectural design objectives and by small modifications on components and joints, it is easy to obtain different and adaptable load-optimized component alternatives for flexible spaces.Keywords: adaptability, durability, open building, service life, structural building system
Procedia PDF Downloads 3701424 Decarboxylation of Waste Coconut Oil and Comparison of Acid Values
Authors: Pabasara H. Gamage, Sisira K. Weliwegamage, Sameera R. Gunatilake, Hondamuni I. C De Silva, Parakrama Karunaratne
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Green diesel is an upcoming category of biofuels, which has more practical advantages than biodiesel. Production of green diesel involves production of hydrocarbons from various fatty acid sources. Though green diesel is chemically similar to fossil fuel hydrocarbons, it is more environmentally friendly. Decarboxylation of fatty acid sources is one of green diesel production methods and is less expensive and more energy efficient compared to hydrodeoxygenation. Free fatty acids (FFA), undergo decarboxylation readily than triglycerides. Waste coconut oil, which is a rich source of FFA, can be easily decarboxylated than other oils which have lower FFA contents. These free fatty acids can be converted to hydrocarbons by decarboxylation. Experiments were conducted to carry out decarboxylation of waste coconut oil in a high pressure hastealloy reactor (Toption Goup LTD), in the presence of soda lime and mixtures of soda lime and alumina. Acid value (AV) correlates to the amount of FFA available in a sample of oil. It can be shown that with the decreasing of AV, FFAs have converted to hydrocarbons. First, waste coconut oil was reacted with soda lime alone, at 150 °C, 200 °C, and 250 °C and 1.2 MPa pressure for 2 hours. AVs of products at different temperatures were compared. AV of products decreased with increasing temperature. Thereafter, different mixtures of soda lime and alumina (100% Soda lime, 1:1 soda lime and alumina and 100% alumina) were employed at temperatures 150 °C, 200 °C, and 250 °C and 1.2 MPa pressure. The lowest AV of 2.99±0.03 was obtained when 1:1 soda lime and alumina were employed at 250 °C. It can be concluded with respect to the AV that the amount of FFA decreased when decarboxylation temperature was increased. Soda lime:alumina 1:1 mixture showed the lowest AV among the compositions studied. These findings lead to formulate a method to successfully synthesize hydrocarbons by decarboxylating waste coconut oil in the presence of soda lime and alumina (1:1) at elevated tempertaures such as 250 °C.Keywords: acid value, free fatty acids, green diesel, high pressure reactor, waste coconut oil
Procedia PDF Downloads 3021423 In situ Real-Time Multivariate Analysis of Methanolysis Monitoring of Sunflower Oil Using FTIR
Authors: Pascal Mwenge, Tumisang Seodigeng
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The combination of world population and the third industrial revolution led to high demand for fuels. On the other hand, the decrease of global fossil 8fuels deposits and the environmental air pollution caused by these fuels has compounded the challenges the world faces due to its need for energy. Therefore, new forms of environmentally friendly and renewable fuels such as biodiesel are needed. The primary analytical techniques for methanolysis yield monitoring have been chromatography and spectroscopy, these methods have been proven reliable but are more demanding, costly and do not provide real-time monitoring. In this work, the in situ monitoring of biodiesel from sunflower oil using FTIR (Fourier Transform Infrared) has been studied; the study was performed using EasyMax Mettler Toledo reactor equipped with a DiComp (Diamond) probe. The quantitative monitoring of methanolysis was performed by building a quantitative model with multivariate calibration using iC Quant module from iC IR 7.0 software. 15 samples of known concentrations were used for the modelling which were taken in duplicate for model calibration and cross-validation, data were pre-processed using mean centering and variance scale, spectrum math square root and solvent subtraction. These pre-processing methods improved the performance indexes from 7.98 to 0.0096, 11.2 to 3.41, 6.32 to 2.72, 0.9416 to 0.9999, RMSEC, RMSECV, RMSEP and R2Cum, respectively. The R2 value of 1 (training), 0.9918 (test), 0.9946 (cross-validation) indicated the fitness of the model built. The model was tested against univariate model; small discrepancies were observed at low concentration due to unmodelled intermediates but were quite close at concentrations above 18%. The software eliminated the complexity of the Partial Least Square (PLS) chemometrics. It was concluded that the model obtained could be used to monitor methanol of sunflower oil at industrial and lab scale.Keywords: biodiesel, calibration, chemometrics, methanolysis, multivariate analysis, transesterification, FTIR
Procedia PDF Downloads 1511422 Audit Examining Maternity Assessment Suite Triage Compliance with Birmingham Symptom Specific Obstetric Triage System in a London Teaching Hospital
Authors: Sarah Atalla, Shubham Gupta, Kim Alipio, Tanya Maric
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Background: Chelsea and Westminster Hospital have introduced the Birmingham Symptom Specific Obstetric Triage System (BSOTS) for patients who present acutely to the Maternity Assessment Suite (MAS) to prioritise care by urgency. The primary objective was to evaluate whether BSOTS was used appropriately to assess patients (defined as a 90% threshold). The secondary objective was to assess whether patients were seen within their designated triaged timeframe (defined as a 90% threshold). Methodology: MAS records were retrospectively reviewed for a randomly selected one-week period of data from 2020 (21/09/2020 - 27/09/2020). 189 patients presented to MAS during this time. Data were collected on the presenting complaint, time of attendance (divided into four time categories), and triage colour code for the urgency of a review by a doctor (red: immediately, orange: within 15 minutes, yellow: within 1 hour, green: within 4 hours). The number of triage waiting times that were breached and the outcome of the attendance was noted. Results: 49% of patients presenting to MAS during this time period were triaged, which therefore did not meet the 90% target. 67% of patients who were triaged were seen within their allocated timeframe as designated by their triage colour code, which therefore did not meet the 90% target. The most frequent reason for patient attendance was reduced fetal movements (30.5% of attendances). The busiest time of day (when most patients presented) was between 06:01-12:00, and this was also when the highest number of patients were not triaged (26 patients or 54% of patients presenting in this time category). The most used triage category (59%) was the green colour code (to be seen by a doctor within 4 hours), followed by orange (24%), yellow (14%), and red (3%). 45% of triaged patients were admitted, whilst 55% were discharged. 62% of patients allocated to the green triage category were discharged, as compared to 56% of yellow category patients, 27% of orange category patients, and 50% of red category patients. The time of patient presentation to the hospital was also associated with the level of urgency and outcome. Patients presenting from 12:01 to 18:00 were more likely to be discharged (72% discharged) compared to 00:01-06:00 where only 12.5% of patients were discharged. Conclusion: The triage system for assessing the urgency of acutely presenting obstetric patients is only being effectively utilised for 49% of patients. There is potential for enhancing the employment of the triage system to enable further efficiency and boost the promotion of patient safety. It is noted that MAS was busiest at 06:01 - 12:00 when there was also the highest number of non-triaged patients – this highlights some areas where we can improve, including higher levels of staffing, better use of BSOTS to triage patients, and patient education.Keywords: birmingham, BSOTS, maternal, obstetric, pregnancy, specific, symptom, triage
Procedia PDF Downloads 1081421 Modelling of Damage as Hinges in Segmented Tunnels
Authors: Gelacio JuáRez-Luna, Daniel Enrique GonzáLez-RamíRez, Enrique Tenorio-Montero
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Frame elements coupled with springs elements are used for modelling the development of hinges in segmented tunnels, the spring elements modelled the rotational, transversal and axial failure. These spring elements are equipped with constitutive models to include independently the moment, shear force and axial force, respectively. These constitutive models are formulated based on damage mechanics and experimental test reported in the literature review. The mesh of the segmented tunnels was discretized in the software GID, and the nonlinear analyses were carried out in the finite element software ANSYS. These analyses provide the capacity curve of the primary and secondary lining of a segmented tunnel. Two numerical examples of segmented tunnels show the capability of the spring elements to release energy by the development of hinges. The first example is a segmental concrete lining discretized with frame elements loaded until hinges occurred in the lining. The second example is a tunnel with primary and secondary lining, discretized with a double ring frame model. The outer ring simulates the segmental concrete lining and the inner ring simulates the secondary cast-in-place concrete lining. Spring elements also modelled the joints between the segments in the circumferential direction and the ring joints, which connect parallel adjacent rings. The computed load vs displacement curves are congruent with numerical and experimental results reported in the literature review. It is shown that the modelling of a tunnel with primary and secondary lining with frame elements and springs provides reasonable results and save computational cost, comparing with 2D or 3D models equipped with smeared crack models.Keywords: damage, hinges, lining, tunnel
Procedia PDF Downloads 3941420 Water Droplet Impact on Vibrating Rigid Superhydrophobic Surfaces
Authors: Jingcheng Ma, Patricia B. Weisensee, Young H. Shin, Yujin Chang, Junjiao Tian, William P. King, Nenad Miljkovic
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Water droplet impact on surfaces is a ubiquitous phenomenon in both nature and industry. The transfer of mass, momentum and energy can be influenced by the time of contact between droplet and surface. In order to reduce the contact time, we study the influence of substrate motion prior to impact on the dynamics of droplet recoil. Using optical high speed imaging, we investigated the impact dynamics of macroscopic water droplets (~ 2mm) on rigid nanostructured superhydrophobic surfaces vibrating at 60 – 300 Hz and amplitudes of 0 – 3 mm. In addition, we studied the influence of the phase of the substrate at the moment of impact on total contact time. We demonstrate that substrate vibration can alter droplet dynamics, and decrease total contact time by as much as 50% compared to impact on stationary rigid superhydrophobic surfaces. Impact analysis revealed that the vibration frequency mainly affected the maximum contact time, while the amplitude of vibration had little direct effect on the contact time. Through mathematical modeling, we show that the oscillation amplitude influences the possibility density function of droplet impact at a given phase, and thus indirectly influences the average contact time. We also observed more vigorous droplet splashing and breakup during impact at larger amplitudes. Through semi-empirical mathematical modeling, we describe the relationship between contact time and vibration frequency, phase, and amplitude of the substrate. We also show that the maximum acceleration during the impact process is better suited as a threshold parameter for the onset of splashing than a Weber-number criterion. This study not only provides new insights into droplet impact physics on vibrating surfaces, but develops guidelines for the rational design of surfaces to achieve controllable droplet wetting in applications utilizing vibration.Keywords: contact time, impact dynamics, oscillation, pear-shape droplet
Procedia PDF Downloads 4551419 Simulation and Performance Evaluation of Transmission Lines with Shield Wire Segmentation against Atmospheric Discharges Using ATPDraw
Authors: Marcio S. da Silva, Jose Mauricio de B. Bezerra, Antonio E. de A. Nogueira
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This paper aims to make a performance analysis of shield wire transmission lines against atmospheric discharges when it is made the option of sectioning the shield wire and verify if the tolerability of the change. As a goal of this work, it was established to make complete modeling of a transmission line in the ATPDraw program with shield wire grounded in all the towers and in some towers. The methodology used to make the proposed evaluation was to choose an actual transmission line that served as a case study. From the choice of transmission line and verification of all its topology and materials, complete modeling of the line using the ATPDraw software was performed. Then several atmospheric discharges were simulated by striking the grounded shield wires in each tower. These simulations served to identify the behavior of the existing line against atmospheric discharges. After this first analysis, the same line was reconsidered with shield wire segmentation. The shielding wire segmentation technique aims to reduce induced losses in shield wires and is adopted in some transmission lines in Brazil. With the same conditions of atmospheric discharge the transmission line, this time with shield wire segmentation was again evaluated. The results obtained showed that it is possible to obtain similar performances against atmospheric discharges between a shield wired line in multiple towers and the same line with shield wire segmentation if some precautions are adopted as verification of the ground resistance of the wire segmented shield, adequacy of the maximum length of the segmented gap, evaluation of the separation length of the electrodes of the insulator spark, among others. As a conclusion, it is verified that since the correct assessment and adopted the correct criteria of adjustment a transmission line with shielded wire segmentation can perform very similar to the traditional use with multiple earths. This solution contributes in a very important way to the reduction of energy losses in transmission lines.Keywords: atmospheric discharges, ATPDraw, shield wire, transmission lines
Procedia PDF Downloads 1711418 Carbon Footprint of Road Project for Sustainable Development: Lessons Learnt from Traffic Management of a Developing Urban Centre
Authors: Sajjad Shukur Ullah, Syed Shujaa Safdar Gardezi
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Road infrastructure plays a vital role in the economic activities of any economy. Besides derived benefits from these facilities, the utilization of extensive energy resources, fuels, and materials results in a negative impact on the environment in terms of carbon footprint; carbon footprint is the overall amount of greenhouse gas (GHG) generated from any action. However, this aspect of environmental impact from road structure is not seriously considered during such developments, thus undermining a critical factor of sustainable development, which usually remains unaddressed, especially in developing countries. The current work investigates the carbon footprint impact of a small road project (0.8 km, dual carriageway) initiated for traffic management in an urban centre. Life cycle assessment (LCA) with boundary conditions of cradle to the site has been adopted. The only construction phase of the life cycle has been assessed at this stage. An impact of 10 ktons-CO2 (6260 ton-CO2/km) has been assessed. The rigid pavement dominated the contributions as compared to a flexible component. Among the structural elements, the underpass works shared the major portion. Among the materials, the concrete and steel utilized for various structural elements resulted in more than 90% of the impact. The earth-moving equipment was dominant in operational carbon. The results have highlighted that road infrastructure projects pose serious threats to the environment during their construction and which need to be considered during the approval stages. This work provides a guideline for supporting sustainable development that could only be ensured when such endeavours are properly assessed by industry professionals and decide various alternative environmental conscious solutions for the future.Keywords: construction waste management, kiloton, life cycle assessment, rigid pavement
Procedia PDF Downloads 1011417 Adhesive Bonded Joints Characterization and Crack Propagation in Composite Materials under Cyclic Impact Fatigue and Constant Amplitude Fatigue Loadings
Authors: Andres Bautista, Alicia Porras, Juan P. Casas, Maribel Silva
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The Colombian aeronautical industry has stimulated research in the mechanical behavior of materials under different loading conditions aircrafts are generally exposed during its operation. The Calima T-90 is the first military aircraft built in the country, used for primary flight training of Colombian Air Force Pilots, therefore, it may be exposed to adverse operating situations such as hard landings which cause impact loads on the aircraft that might produce the impact fatigue phenomenon. The Calima T-90 structure is mainly manufactured by composites materials generating assemblies and subassemblies of different components of it. The main method of bonding these components is by using adhesive joints. Each type of adhesive bond must be studied on its own since its performance depends on the conditions of the manufacturing process and operating characteristics. This study aims to characterize the typical adhesive joints of the aircraft under usual loads. To this purpose, the evaluation of the effect of adhesive thickness on the mechanical performance of the joint under quasi-static loading conditions, constant amplitude fatigue and cyclic impact fatigue using single lap-joint specimens will be performed. Additionally, using a double cantilever beam specimen, the influence of the thickness of the adhesive on the crack growth rate for mode I delamination failure, as a function of the critical energy release rate will be determined. Finally, an analysis of the fracture surface of the test specimens considering the mechanical interaction between the substrate (composite) and the adhesive, provide insights into the magnitude of the damage, the type of failure mechanism that occurs and its correlation with the way crack propagates under the proposed loading conditions.Keywords: adhesive, composites, crack propagation, fatigue
Procedia PDF Downloads 2071416 Studies on Distribution of the Doped Pr3+ Ions in the LaF3 Based Transparent Oxyfluoride Glass-Ceramic
Authors: Biswajit Pal, Amit Mallik, Anil K. Barik
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Current years have witnessed a phenomenal growth in the research on the rare earth-doped transparent host materials, the essential components in optoelectronics that meet up the increasing demand for fabrication of high quality optical devices especially in telecommunication system. The combination of low phonon energy (because of fluoride environment) and high chemical durability with superior mechanical stability (due to oxide environment) makes the oxyfluoride glass–ceramics the promising and useful materials in optoelectronics. The present work reports on the undoped and doped (1 mol% Pr2O3) glass ceramics of composition 16.52 Al2O3•1.5AlF3• 12.65LaF3•4.33Na2O•64.85 SiO2 (mol%), prepared by melting technique initially that follows annealation at 450 ºC for 1 h. The glass samples so obtained were heat treated at constant 600 ºC with a variation in heat treatment schedule (10- 80 h). TEM techniques were employed to structurally characterize the glass samples. Pr2O3 affects the phase separation in the glass and delays the onset of crystallization in the glass ceramic. The modified crystallization mechanism is established from the analysis of advanced STEM/EDXS results. The phase separated droplets after annealing turn into 10-20 nm of LaF3 nano crystals those upon scrutiny are found to be dotted with the doped Pr3+ ions within the crystals themselves. The EDXS results also suggest that the inner LaF3 crystal core is swallowed by an Al enriched layer that follows a Si enriched surrounding shell as the outer core. This greatly increases the viscosity in the periphery of the crystals that restricts further crystal growth to account for the formation of nano sized crystals.Keywords: advanced STEM/EDXS, crystallization mechanism, nano crystals, pr3+ ion doped glass and glass ceramic, structural characterization
Procedia PDF Downloads 1881415 Recent Progress in the Uncooled Mid-Infrared Lead Selenide Polycrystalline Photodetector
Authors: Hao Yang, Lei Chen, Ting Mei, Jianbang Zheng
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Currently, the uncooled PbSe photodetectors in the mid-infrared range (2-5μm) with sensitization technology extract more photoelectric response than traditional ones, and enable the room temperature (300K) photo-detection with high detectivity, which have attracted wide attentions in many fields. This technology generally contains the film fabrication with vapor phase deposition (VPD) and a sensitizing process with doping of oxygen and iodine. Many works presented in the recent years almost provide and high temperature activation method with oxygen/iodine vapor diffusion, which reveals that oxygen or iodine plays an important role in the sensitization of PbSe material. In this paper, we provide our latest experimental results and discussions in the stoichiometry of oxygen and iodine and its influence on the polycrystalline structure and photo-response. The experimental results revealed that crystal orientation was transformed from (200) to (420) by sensitization, and the responsivity of 5.42 A/W was gained by the optimal stoichiometry of oxygen and iodine with molecular density of I2 of ~1.51×1012 mm-3 and oxygen pressure of ~1Mpa. We verified that I2 plays a role in transporting oxygen into the lattice of crystal, which is actually not its major role. It is revealed that samples sensitized with iodine transform atomic proportion of Pb from 34.5% to 25.0% compared with samples without iodine from XPS data, which result in the proportion of about 1:1 between Pb and Se atoms by sublimation of PbI2 during sensitization process, and Pb/Se atomic proportion is controlled by I/O atomic proportion in the polycrystalline grains, which is very an important factor for improving responsivity of uncooled PbSe photodetector. Moreover, a novel sensitization and dopant activation method is proposed using oxygen ion implantation with low ion energy of < 500eV and beam current of ~120μA/cm2. These results may be helpful to understanding the sensitization mechanism of polycrystalline lead salt materials.Keywords: polycrystalline PbSe, sensitization, transport, stoichiometry
Procedia PDF Downloads 3521414 Formulation and Characterization of NaCS-PDMDAAC Capsules with Immobilized Chlorella vulgaris for Phycoremediation of Palm Oil Mill Effluent
Authors: Quin Emparan, Razif Harun, Dayang R. A. Biak, Rozita Omar, Michael K. Danquah
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Cultivation of immobilized microalgae cells is on the rise for biotechnological applications. In this study, cultivation of Chlorella vulgaris was carried out in the form of suspended free-cell and immobilized cells system. NaCS-PDMDAAC capsules were used to immobilize C. vulgaris. Initially, the synthesized NaCS with C. vulgaris culture were prepared at various concentration of 5- 20% (w/v) using a 6% hardening solution (PDMDAAC) to investigate the capsules' gel stability and suitability for microalgae cells growth. Then, the capsules produced from 15% NaCS with C. vulgaris culture were furthered investigated using 5%, 10%, and 15% (w/v) of PDMDAAC solution. The capsules' gel stability was evaluated through dissolution time and loss of uniform spherical shape of capsules, while suitability for microalgae cells growth was evaluated through the optical density of microalgae. In this study, the 15% NaCS-10% PDMDAAC capsules were found to be the most suitable to sustain the capsules' gel stability and microalgae cells growth in MLA. For that reason, the C. vulgaris immobilized in the 15% NaCS-10% PDMDAAC capsules were further characterized using physicochemical analysis in terms of morphological, carbon (C), hydrogen (H) and nitrogen (N), Fourier transform-infrared (FT-IR), scanning electron microscopy-energy dispersive X-ray (SEM-EDX), zeta potential and Brunauer-Emmet-Teller (BET) analyses. The results revealed that the presence of sulfonates in the synthesized NaCS and NaCS-PDMDAAC capsules without and with C. vulgaris proves that cellulose alcohol group was successfully bonded by sulfo group. Besides that, immobilized microalgae cells have a smaller cell size of 6.29 ± 1.09 µm and zeta potential of -11.93 ± 0.91 mV than suspended free-cells microalgae culture. It can be summarized that immobilization of C. vulgaris in the 15% NaCS-10% PDMDAAC capsules are relevant as a bioremediator for wastewater treatment purposes due to its suitable size of pore and capsules as well as structural and compositional properties.Keywords: biological capsules, immobilized cultivation, microalgae, physico-chemical analysis
Procedia PDF Downloads 1731413 Modeling of Bipolar Charge Transport through Nanocomposite Films for Energy Storage
Authors: Meng H. Lean, Wei-Ping L. Chu
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The effects of ferroelectric nanofiller size, shape, loading, and polarization, on bipolar charge injection, transport, and recombination through amorphous and semicrystalline polymers are studied. A 3D particle-in-cell model extends the classical electrical double layer representation to treat ferroelectric nanoparticles. Metal-polymer charge injection assumes Schottky emission and Fowler-Nordheim tunneling, migration through field-dependent Poole-Frenkel mobility, and recombination with Monte Carlo selection based on collision probability. A boundary integral equation method is used for solution of the Poisson equation coupled with a second-order predictor-corrector scheme for robust time integration of the equations of motion. The stability criterion of the explicit algorithm conforms to the Courant-Friedrichs-Levy limit. Trajectories for charge that make it through the film are curvilinear paths that meander through the interspaces. Results indicate that charge transport behavior depends on nanoparticle polarization with anti-parallel orientation showing the highest leakage conduction and lowest level of charge trapping in the interaction zone. Simulation prediction of a size range of 80 to 100 nm to minimize attachment and maximize conduction is validated by theory. Attached charge fractions go from 2.2% to 97% as nanofiller size is decreased from 150 nm to 60 nm. Computed conductivity of 0.4 x 1014 S/cm is in agreement with published data for plastics. Charge attachment is increased with spheroids due to the increase in surface area, and especially so for oblate spheroids showing the influence of larger cross-sections. Charge attachment to nanofillers and nanocrystallites increase with vol.% loading or degree of crystallinity, and saturate at about 40 vol.%.Keywords: nanocomposites, nanofillers, electrical double layer, bipolar charge transport
Procedia PDF Downloads 3591412 Film Dosimetry – An Asset for Collaboration Between Cancer Radiotherapy Centers at Established Institutions and Those Located in Low- and Middle-Income Countries
Authors: A. Fomujong, P. Mobit, A. Ndlovu, R. Teboh
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Purpose: Film’s unique qualities, such as tissue equivalence, high spatial resolution, near energy independence and comparatively less expensive dosimeter, ought to make it the preferred and widely used in radiotherapy centers in low and middle income countries (LMICs). This, however, is not always the case, as other factors that are often maybe taken for granted in advanced radiotherapy centers remain a challenge in LMICs. We explored the unique qualities of film dosimetry that can make it possible for one Institution to benefit from another’s protocols via collaboration. Methods: For simplicity, two Institutions were considered in this work. We used a single batch of films (EBT-XD) and established a calibration protocol, including scan protocols and calibration curves, using the radiotherapy delivery system at Institution A. We then proceeded and performed patient-specific QA for patients treated on system A (PSQA-A-A). Films from the same batch were then sent to a remote center for PSQA on radiotherapy delivery system B. Irradiations were done at Institution B and then returned to Institution A for processing and analysis (PSQA-B-A). The following points were taken into consideration throughout the process (a) A reference film was irradiated to a known dose on the same system irradiating the PSQA film. (b) For calibration, we utilized the one-scan protocol and maintained the same scan orientation of the calibration, PSQA and reference films. Results: Gamma index analysis using a dose threshold of 10% and 3%/2mm criteria showed a gamma passing rate of 99.8% and 100% for the PSQA-A-A and PSQA-B-A, respectively. Conclusion: This work demonstrates that one could use established film dosimetry protocols in one Institution, e.g., an advanced radiotherapy center and apply similar accuracies to irradiations performed at another institution, e.g., a center located in LMIC, which thus encourages collaboration between the two for worldwide patient benefits.Keywords: collaboration, film dosimetry, LMIC, radiotherapy, calibration
Procedia PDF Downloads 781411 Effect of Cryogenic Pre-stretching on the Room Temperature Tensile Behavior of AZ61 Magnesium Alloy and Dominant Grain Growth Mechanisms During Subsequent Annealing
Authors: Umer Masood Chaudry, Hafiz Muhammad Rehan Tariq, Chung-soo Kim, Tea-sung Jun
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This study explored the influence of pre-stretching temperature on the microstructural characteristics and deformation behavior of AZ61 magnesium alloy and its implications on grain growth during subsequent annealing. AZ61 alloy was stretched to 5% plastic strain along rolling (RD) and transverse direction (TD) at room (RT) and cryogenic temperature (-150 oC, CT) followed by annealing at 320 oC for 1 h to investigate the twinning and dislocation evolution and its consequent effect on the flow stress, plastic strain and strain hardening rate. Compared to RT-stretched samples, significant improvement in yield stress, strain hardening rate and moderate reduction in elongation to failure were witnessed for CT-stretched samples along RD and TD. The subsequent EBSD analysis revealed the increased fraction of fine {10-12} twins and nucleation of multiple {10-12} twin variants caused by higher local stress concentration at the grain boundaries in CT-stretched samples as manifested by the kernel average misorientation. This higher twin fraction and twin-twin interaction imposed the strengthening by restricting the mean free path of dislocations, leading to higher flow stress and strain hardening rate. During annealing of the RT/CT-stretched samples, the residual strain energy and twin boundaries were decreased due to static recovery, leading to a coarse-grained twin-free microstructure. Strain induced boundary migration (SBIM) was found to be the predominant mechanism governing the grain growth during annealing via movement of high angle grain boundaries.Keywords: magnesium, twinning, twinning variant selection, EBSD, cryogenic deformation
Procedia PDF Downloads 701410 Fragility Analysis of a Soft First-Story Building in Mexico City
Authors: Rene Jimenez, Sonia E. Ruiz, Miguel A. Orellana
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On 09/19/2017, a Mw = 7.1 intraslab earthquake occurred in Mexico causing the collapse of about 40 buildings. Many of these were 5- or 6-story buildings with soft first story; so, it is desirable to perform a structural fragility analysis of typical structures representative of those buildings and to propose a reliable structural solution. Here, a typical 5-story building constituted by regular R/C moment-resisting frames in the first story and confined masonry walls in the upper levels, similar to the collapsed structures on the 09/19/2017 Mexico earthquake, is analyzed. Three different structural solutions of the 5-story building are considered: S1) it is designed in accordance with the Mexico City Building Code-2004; S2) then, the column dimensions of the first story corresponding to S1 are reduced, and S3) viscous dampers are added at the first story of solution S2. A number of dynamic incremental analyses are performed for each structural solution, using a 3D structural model. The hysteretic behavior model of the masonry was calibrated with experiments performed at the Laboratory of Structures at UNAM. Ten seismic ground motions are used to excite the structures; they correspond to ground motions recorded in intermediate soil of Mexico City with a dominant period around 1s, where the structures are located. The fragility curves of the buildings are obtained for different values of the maximum inter-story drift demands. Results show that solutions S1 and S3 give place to similar probabilities of exceedance of a given value of inter-story drift for the same seismic intensity, and that solution S2 presents a higher probability of exceedance for the same seismic intensity and inter-story drift demand. Therefore, it is concluded that solution S3 (which corresponds to the building with soft first story and energy dissipation devices) can be a reliable solution from the structural point of view.Keywords: demand hazard analysis, fragility curves, incremental dynamic analyzes, soft-first story, structural capacity
Procedia PDF Downloads 1781409 BI- And Tri-Metallic Catalysts for Hydrogen Production from Hydrogen Iodide Decomposition
Authors: Sony, Ashok N. Bhaskarwar
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Production of hydrogen from a renewable raw material without any co-synthesis of harmful greenhouse gases is the current need for sustainable energy solutions. The sulfur-iodine (SI) thermochemical cycle, using intermediate chemicals, is an efficient process for producing hydrogen at a much lower temperature than that required for the direct splitting of water. No net byproduct forms in the cycle. Hydrogen iodide (HI) decomposition is a crucial reaction in this cycle, as the product, hydrogen, forms only in this step. It is an endothermic, reversible, and equilibrium-limited reaction. The theoretical equilibrium conversion at 550°C is just a meagre of 24%. There is a growing interest, therefore, in enhancing the HI conversion to near-equilibrium values at lower reaction temperatures and by possibly improving the rate. The reaction is relatively slow without a catalyst, and hence catalytic decomposition of HI has gained much significance. Bi-metallic Ni-Co, Ni-Mn, Co-Mn, and tri-metallic Ni-Co-Mn catalysts over zirconia support were tested for HI decomposition reaction. The catalysts were synthesized via a sol-gel process wherein Ni was 3wt% in all the samples, and Co and Mn had equal weight ratios in the Co-Mn catalyst. Powdered X-ray diffraction and Brunauer-Emmett-Teller surface area characterizations indicated the polycrystalline nature and well-developed mesoporous structure of all the samples. The experiments were performed in a vertical laboratory-scale packed bed reactor made of quartz, and HI (55 wt%) was fed along with nitrogen at a WHSV of 12.9 hr⁻¹. Blank experiments at 500°C for HI decomposition suggested conversion of less than 5%. The activities of all the different catalysts were checked at 550°C, and the highest conversion of 23.9% was obtained with the tri-metallic 3Ni-Co-Mn-ZrO₂ catalyst. The decreasing order of the performance of catalysts could be expressed as: 3Ni-Co-Mn-ZrO₂ > 3Ni-2Co-ZrO₂ > 3Ni-2Mn-ZrO₂ > 2.5Co-2.5Mn-ZrO₂. The tri-metallic catalyst remained active till 360 mins at 550°C without any observable drop in its activity/stability. Among the explored catalyst compositions, the tri-metallic catalyst certainly has a better performance for HI conversion when compared to the bi-metallic ones. Owing to their low costs and ease of preparation, these trimetallic catalysts could be used for large-scale hydrogen production.Keywords: sulfur-iodine cycle, hydrogen production, hydrogen iodide decomposition, bi-, and tri-metallic catalysts
Procedia PDF Downloads 1901408 Evaluation of Sequential Polymer Flooding in Multi-Layered Heterogeneous Reservoir
Authors: Panupong Lohrattanarungrot, Falan Srisuriyachai
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Polymer flooding is a well-known technique used for controlling mobility ratio in heterogeneous reservoirs, leading to improvement of sweep efficiency as well as wellbore profile. However, low injectivity of viscous polymer solution attenuates oil recovery rate and consecutively adds extra operating cost. An attempt of this study is to improve injectivity of polymer solution while maintaining recovery factor, enhancing effectiveness of polymer flooding method. This study is performed by using reservoir simulation program to modify conventional single polymer slug into sequential polymer flooding, emphasizing on increasing of injectivity and also reduction of polymer amount. Selection of operating conditions for single slug polymer including pre-injected water, polymer concentration and polymer slug size is firstly performed for a layered-heterogeneous reservoir with Lorenz coefficient (Lk) of 0.32. A selected single slug polymer flooding scheme is modified into sequential polymer flooding with reduction of polymer concentration in two different modes: Constant polymer mass and reduction of polymer mass. Effects of Residual Resistance Factor (RRF) is also evaluated. From simulation results, it is observed that first polymer slug with the highest concentration has the main function to buffer between displacing phase and reservoir oil. Moreover, part of polymer from this slug is also sacrificed for adsorption. Reduction of polymer concentration in the following slug prevents bypassing due to unfavorable mobility ratio. At the same time, following slugs with lower viscosity can be injected easily through formation, improving injectivity of the whole process. A sequential polymer flooding with reduction of polymer mass shows great benefit by reducing total production time and amount of polymer consumed up to 10% without any downside effect. The only advantage of using constant polymer mass is slightly increment of recovery factor (up to 1.4%) while total production time is almost the same. Increasing of residual resistance factor of polymer solution yields a benefit on mobility control by reducing effective permeability to water. Nevertheless, higher adsorption results in low injectivity, extending total production time. Modifying single polymer slug into sequence of reduced polymer concentration yields major benefits on reducing production time as well as polymer mass. With certain design of polymer flooding scheme, recovery factor can even be further increased. This study shows that application of sequential polymer flooding can be certainly applied to reservoir with high value of heterogeneity since it requires nothing complex for real implementation but just a proper design of polymer slug size and concentration.Keywords: polymer flooding, sequential, heterogeneous reservoir, residual resistance factor
Procedia PDF Downloads 4811407 R Statistical Software Applied in Reliability Analysis: Case Study of Diesel Generator Fans
Authors: Jelena Vucicevic
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Reliability analysis represents a very important task in different areas of work. In any industry, this is crucial for maintenance, efficiency, safety and monetary costs. There are ways to calculate reliability, unreliability, failure density and failure rate. This paper will try to introduce another way of calculating reliability by using R statistical software. R is a free software environment for statistical computing and graphics. It compiles and runs on a wide variety of UNIX platforms, Windows and MacOS. The R programming environment is a widely used open source system for statistical analysis and statistical programming. It includes thousands of functions for the implementation of both standard and new statistical methods. R does not limit user only to operation related only to these functions. This program has many benefits over other similar programs: it is free and, as an open source, constantly updated; it has built-in help system; the R language is easy to extend with user-written functions. The significance of the work is calculation of time to failure or reliability in a new way, using statistic. Another advantage of this calculation is that there is no need for technical details and it can be implemented in any part for which we need to know time to fail in order to have appropriate maintenance, but also to maximize usage and minimize costs. In this case, calculations have been made on diesel generator fans but the same principle can be applied to any other part. The data for this paper came from a field engineering study of the time to failure of diesel generator fans. The ultimate goal was to decide whether or not to replace the working fans with a higher quality fan to prevent future failures. Seventy generators were studied. For each one, the number of hours of running time from its first being put into service until fan failure or until the end of the study (whichever came first) was recorded. Dataset consists of two variables: hours and status. Hours show the time of each fan working and status shows the event: 1- failed, 0- censored data. Censored data represent cases when we cannot track the specific case, so it could fail or success. Gaining the result by using R was easy and quick. The program will take into consideration censored data and include this into the results. This is not so easy in hand calculation. For the purpose of the paper results from R program have been compared to hand calculations in two different cases: censored data taken as a failure and censored data taken as a success. In all three cases, results are significantly different. If user decides to use the R for further calculations, it will give more precise results with work on censored data than the hand calculation.Keywords: censored data, R statistical software, reliability analysis, time to failure
Procedia PDF Downloads 4021406 In Silico Exploration of Quinazoline Derivatives as EGFR Inhibitors for Lung Cancer: A Multi-Modal Approach Integrating QSAR-3D, ADMET, Molecular Docking, and Molecular Dynamics Analyses
Authors: Mohamed Moussaoui
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A series of thirty-one potential inhibitors targeting the epidermal growth factor receptor kinase (EGFR), derived from quinazoline, underwent 3D-QSAR analysis using CoMFA and CoMSIA methodologies. The training and test sets of quinazoline derivatives were utilized to construct and validate the QSAR models, respectively, with dataset alignment performed using the lowest energy conformer of the most active compound. The best-performing CoMFA and CoMSIA models demonstrated impressive determination coefficients, with R² values of 0.981 and 0.978, respectively, and Leave One Out cross-validation determination coefficients, Q², of 0.645 and 0.729, respectively. Furthermore, external validation using a test set of five compounds yielded predicted determination coefficients, R² test, of 0.929 and 0.909 for CoMFA and CoMSIA, respectively. Building upon these promising results, eighteen new compounds were designed and assessed for drug likeness and ADMET properties through in silico methods. Additionally, molecular docking studies were conducted to elucidate the binding interactions between the selected compounds and the enzyme. Detailed molecular dynamics simulations were performed to analyze the stability, conformational changes, and binding interactions of the quinazoline derivatives with the EGFR kinase. These simulations provided deeper insights into the dynamic behavior of the compounds within the active site. This comprehensive analysis enhances the understanding of quinazoline derivatives as potential anti-cancer agents and provides valuable insights for lead optimization in the early stages of drug discovery, particularly for developing highly potent anticancer therapeuticsKeywords: 3D-QSAR, CoMFA, CoMSIA, ADMET, molecular docking, quinazoline, molecular dynamic, egfr inhibitors, lung cancer, anticancer
Procedia PDF Downloads 521405 Effect of a Nutritional Supplement Containing Euterpe oleracea Mart., Inulin, Phaseolus vulgaris and Caralluma fimbriata in Persons with Metabolic Syndrome
Authors: Eduardo Cabrera-Rode, Janet Rodriguez, Aimee Alvarez, Ragmila Echevarria, Antonio D. Reyes, Ileana Cubas-Duenas, Silvia E. Turcios, Oscar Diaz-Diaz
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Obex is a nutritional supplement to help weight loss naturally. In addition, this supplement has a satiating effect that helps control the craving to eat between meals. The purpose of this study was to evaluate the effect of Obex in the metabolic syndrome (MS). This was an open label pilot study conducted in 30 patients with MS and ages between 29 and 60 years old. Participants received Obex, at a dose of one sachet before (30 to 45 minutes) the two main meals (lunch and dinner) daily (mean two sachets per day) for 3 months. The content of the sachets was dissolved in a glass of water or fruit juice. Obex ingredients: Açai (Euterpe oleracea Mart.) berry, inulin, Phaseolus vulgaris, Caralluma fimbriata, inositol, choline, arginine, ornitine, zinc sulfate, carnitine fumarate, methionine, calcium pantothenate, pyridoxine and folic acid. In addition to anthropometric measures and blood pressure, fasting plasma glucose, total cholesterol, triglycerides and HDL-cholesterol and insulin were determined. Insulin resistance was assessed by HOMA-IR index. Three indirect indexes were used to calculate insulin sensitivity [QUICKI index (Quantitative insulin sensitivity check index), Bennett index and Raynaud index]. Metabolic syndrome was defined according to the Joint Interim Statement (JIS) criteria. The JIS criteria require at least three of the following components: (1) abdominal obesity (waist circumference major or equal major or equal 94 cm for men or 80 cm for women), (2) triglycerides major or equal 1.7 mmol/L, (3) HDL cholesterol minor 1.03 mmol/L for men or minor 1.30 mmol/L for women, (4) systolic/diastolic blood pressure major or equal 130/85mmHg or use antihypertensive drugs, and (5) fasting plasma glucose major or equal 5.6 mmol/L or known treatment for diabetes. This study was approved by the Ethical and Research Committee of the National Institute of Endocrinology, Cuba and conducted according to the Declaration of Helsinki. Obex is registered as a food supplement in the National Institute of Nutrition and Food, Havana, Cuba. Written consent was obtained from all patients before the study. The clinical trial had been registered at ClinicalTrials.gov. After three months of treatment, 43.3% (13/30) of participants decreased the frequency of MS. Compared to baseline, Obex significantly reduced body weight, BMI, waist circumference, and waist/hip ratio and improved HDL-c (p<0.0001) and in addition to lowering blood pressure (p<0.05). After Obex intake, subjects also have shown a reduction in fasting plasma glucose (p<0.0001) and insulin sensitivity was enhanced (p=0.001). No adverse effects were seen in any of the participants during the study. In this pilot study, consumption of Obex decreased the prevalence of MS due to the improved selected components of the metabolic syndrome, indicating that further studies are warranted. Obex emerges as an effective and well tolerated treatment for preventing or delaying MS and therefore potential reduction of cardiovascular risk.Keywords: nutritional supplement, metabolic syndrome, weight loss, insulin resistance
Procedia PDF Downloads 3011404 The Effects of Nanoemulsions Based on Commercial Oils for the Quality of Vacuum-Packed Sea Bass at 2±2°C
Authors: Mustafa Durmuş, Yesim Ozogul, Esra Balıkcı, Saadet Gokdoğan, Fatih Ozogul, Ali Rıza Köşker, İlknur Yuvka
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Food scientists and researchers have paid attention to develop new ways for improving the nutritional value of foods. The application of nanotechnology techniques to the food industry may allow the modification of food texture, taste, sensory attributes, coloring strength, processability, and stability during shelf life of products. In this research, the effects of nanoemulsions based on commercial oils for vacuum-packed sea bass fillets stored at 2±2°C were investigated in terms of the sensory, chemical (total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA), peroxide value (PV) and free fatty acids (FFA), pH, water holding capacity (WHC)) and microbiological qualities (total anaerobic bacteria and total lactic acid bacteria). Physical properties of emulsions (viscosity, the particle size of droplet, thermodynamic stability, refractive index, and surface tension) were determined. Nanoemulsion preparation method was based on high energy principle, with ultrasonic homojenizator. Sensory analyses of raw fish showed that the demerit points of the control group were found higher than those of treated groups. The sensory score (odour, taste and texture) of the cooked fillets decreased with storage time, especially in the control. Results obtained from chemical and microbiological analyses also showed that nanoemulsions significantly (p<0.05) decreased the values of biochemical parameters and growth of bacteria during storage period, thus improving quality of vacuum-packed sea bass.Keywords: quality parameters, nanoemulsion, sea bass, shelf life, vacuum packing
Procedia PDF Downloads 4591403 Microstructure and Mechanical Properties of Low Alloy Steel with Double Austenitizing Tempering Heat Treatment
Authors: Jae-Ho Jang, Jung-Soo Kim, Byung-Jun Kim, Dae-Geun Nam, Uoo-Chang Jung, Yoon-Suk Choi
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Low alloy steels are widely used for pressure vessels, spent fuel storage, and steam generators required to withstand the internal pressure and prevent unexpected failure in nuclear power plants, which these may suffer embrittlement by high levels of radiation and heat for a long period. Therefore, it is important to improve mechanical properties of low alloy steels for the integrity of structure materials at an early stage of fabrication. Recently, it showed that a double austenitizing and tempering (DTA) process resulted in a significant improvement of strength and toughness by refinement of prior austenite grains. In this study, it was investigated that the mechanism of improving mechanical properties according to the change of microstructure by the second fully austenitizing temperature of the DAT process for low alloy steel required the structural integrity. Compared to conventional single austenitizing and tempering (SAT) process, the tensile elongation properties have improved about 5%, DBTTs have obtained result in reduction of about -65℃, and grain size has decreased by about 50% in the DAT process conditions. Grain refinement has crack propagation interference effect due to an increase of the grain boundaries and amount of energy absorption at low temperatures. The higher first austenitizing temperature in the DAT process, the more increase the spheroidized carbides and strengthening the effect of fine precipitates in the ferrite grain. The area ratio of the dimple in the transition area has increased by proportion to the effect of spheroidized carbides. This may the primary mechanisms that can improve low-temperature toughness and elongation while maintaining a similar hardness and strength.Keywords: double austenitizing, Ductile Brittle transition temperature, grain refinement, heat treatment, low alloy steel, low-temperature toughness
Procedia PDF Downloads 513