Search results for: Harsh B. Desai
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 282

Search results for: Harsh B. Desai

102 Effects of Ascophyllum nodosum in Tomato in the Tropical Caribbean Climate: Effects and Molecular Insights into Mechanisms

Authors: Omar Ali, Adesh Ramsubhag, Jayaraj Jayaraman

Abstract:

Seaweed extracts have been reported as plant biostimulants which could be a safer, organic alternative to harsh pesticides. The incentive to use seaweed-based biostimulants is becoming paramount in sustainable agriculture. The current study, therefore, screened a commercial extract of A. nodosum in tomatoes, cultivated in Trinidad to showcase the multiple beneficial effects. Foliar treatment with an A. nodosum commercial extract led to significant increases in fruit yield and a significant reduction of incidence of bacterial spots and early blight diseases under both greenhouse and field conditions. Investigations were carried out to reveal the possible mechanisms of action of this biostimulant through defense enzyme assays and transcriptome profiling via RNA sequencing of tomato. Studies into disease control mechanisms by A. nodosum showed that the extract stimulated the activity of enzymes such as peroxidase, phenylalanine ammonia-lyase, chitinase, polyphenol oxidase, and β-1,3-glucanase. Additionally, the transcriptome survey revealed the upregulation and enrichment of genes responsible for the biosynthesis of growth hormones, defense enzymes, PR proteins and defense-related secondary metabolites, as well as genes involved in the nutrient mobilization, photosynthesis and primary and secondary metabolic pathways. The results of the transcriptome study also demonstrated the cross-talks between growth and defense responses, confirming the bioelicitor and biostimulant value of seaweed extracts in plants. These effects could potentially implicate the benefits of seaweed extract and validate its usage in sustainable crop production.

Keywords: A. nodosum, biostimulants, elicitor, enzymes, growth responses, seaweeds, tomato, transcriptome analysis

Procedia PDF Downloads 137
101 Performance Evaluation of Polyethyleneimine/Polyethylene Glycol Functionalized Reduced Graphene Oxide Membranes for Water Desalination via Forward Osmosis

Authors: Mohamed Edokali, Robert Menzel, David Harbottle, Ali Hassanpour

Abstract:

Forward osmosis (FO) process has stood out as an energy-efficient technology for water desalination and purification, although the practical application of FO for desalination still relies on RO-based Thin Film Composite (TFC) and Cellulose Triacetate (CTA) polymeric membranes which have a low performance. Recently, graphene oxide (GO) laminated membranes have been considered an ideal selection to overcome the bottleneck of the FO-polymeric membranes owing to their simple fabrication procedures, controllable thickness and pore size and high water permeability rates. However, the low stability of GO laminates in wet and harsh environments is still problematic. The recent developments of modified GO and hydrophobic reduced graphene oxide (rGO) membranes for FO desalination have demonstrated attempts to overcome the ongoing trade-off between desalination performance and stability, which is yet to be achieved prior to the practical implementation. In this study, acid-functionalized GO nanosheets cooperatively reduced and crosslinked by the hyperbranched polyethyleneimine (PEI) and polyethylene glycol (PEG) polymers, respectively, are applied for fabrication of the FO membrane, to enhance the membrane stability and performance, and compared with other functionalized rGO-FO membranes. PEI/PEG doped rGO membrane retained two compacted d-spacings (0.7 and 0.31 nm) compared to the acid-functionalized GO membrane alone (0.82 nm). Besides increasing the hydrophilicity, the coating layer of PEG onto the PEI-doped rGO membrane surface enhanced the structural integrity of the membrane chemically and mechanically. As a result of these synergetic effects, the PEI/PEG doped rGO membrane exhibited a water permeation of 7.7 LMH, salt rejection of 97.9 %, and reverse solute flux of 0.506 gMH at low flow rates in the FO desalination process.

Keywords: desalination, forward osmosis, membrane performance, polyethyleneimine, polyethylene glycol, reduced graphene oxide, stability

Procedia PDF Downloads 70
100 Chemical Composition and Nutritional Value of Leaves and Pods of Leucaena Leucocephala, Prosopis Laevigata and Acacia Farnesiana in a Xerophyllous Shrubland

Authors: Miguel Mellado, Cecilia Zapata

Abstract:

Goats can be exploited in harsh environments due to their capacity to adjust to limited quantity and quality forage sources. In these environments, leguminous trees can be used as supplementary feeds as foliage and fruits of these trees can contribute to maintain or improve production efficiency in ruminants. The objective of this study was to determine the nutritional value of three leguminous trees heavily selected by goats in a xerophyllous shrubland. Chemical composition and in vitro dry matter disappearance (IVDMD) of leaves and pods from leucaena (Leucaena leucocephala), mesquite (Prosopis laevigata) and huisache (Acacia farnesiana) is presented. Crude protein (CP) ranged from 17.3% for leaves of huisache to 21.9% for leucaena. The neutral detergent fiber (NDF) content ranged from 39.0 to 40.3 with no difference among fodder threes. Across tree species, mean IVDMD was 61.6% for pods and 52.2% for leaves. IVDMD for leaves was highest (P < 0.01) for leucaena (54.9%) and lowest for huisache (47.3%). Condensed tannins in an acetonic extract were highest for leaves of huisache (45.3 mg CE/g DM) and lowest for mesquite (25.9 mg CE/g DM). Pods and leaves of huisache presented the highest number of secondary metabolites, mainly related to hydrobenzoic acid and flavonols; leucaena and mesquite presented mainly flavonols and anthocyanins. It was concluded that leaves and pods of leucaena, mesquite and huisache constitute valuable forages for ruminant livestock due to its low fiber, high CP levels, moderate in vitro fermentation characteristics and high mineral content. Keywords: Fodder tree; ruminants; secondary metabolites; minerals; tannins

Keywords: fodder tree, ruminants, secondary metabolites, minerals, tannins

Procedia PDF Downloads 113
99 Activity-Based Safety Assessment of Real Estate Projects in Western India

Authors: Patel Parul, Harsh Ganvit

Abstract:

The construction industry is the second highest industry after agriculture provides employment in India. In developing countries like India, many construction projects are coming up to meet the demand. On the one hand, construction projects are increasing; on the other hand still, construction companies are struggling with many problems. One of the major problems is to ensure safe working conditions at the construction site. Due to a lack of safety awareness and ignorance of safety aspects, many fatal accidents are very common at the construction site in India. One of the key success factors for construction projects is “Accident-Free Construction Projects”. The construction projects can be divided into various categories like Infrastructure projects, industrial construction and real estate construction. Real estate projects are mainly comprised of commercial and residential projects. In the construction industry, private sectors play a huge role in urban and rural development and also contribute significantly to the growth of the nation. Infrastructure and Industrial projects are mainly executed by well-qualified construction contractors. For such projects, ensuring safety at construction projects is inevitable and probably one of the major clauses of contract documents as well. These projects are monitored from time to time by national agencies and researchers, too. However, Real estate projects are rarely monitored for safety aspects. No systematic contract system is followed for these projects. Safety is the most neglected aspect of these projects. In the current research projects, an attempt is made to carry out safety auditing for about 75 real estate projects. The objective of this work is to collect the activity-based safety survey of real estate projects in western India. The analysis of activity-based safety implementation for real estate projects is discussed in the present work. The activities are divided into three categories based on the data collected. The findings of this work will help local monitoring authorities to implement a safety management plan for real estate projects.

Keywords: construction safety, safety assessment, activity-based safety, real estate projects

Procedia PDF Downloads 22
98 Comparative Electrochemical Studies of Enzyme-Based and Enzyme-less Graphene Oxide-Based Nanocomposite as Glucose Biosensor

Authors: Chetna Tyagi. G. B. V. S. Lakshmi, Ambuj Tripathi, D. K. Avasthi

Abstract:

Graphene oxide provides a good host matrix for preparing nanocomposites due to the different functional groups attached to its edges and planes. Being biocompatible, it is used in therapeutic applications. As enzyme-based biosensor requires complicated enzyme purification procedure, high fabrication cost and special storage conditions, we need enzyme-less biosensors for use even in a harsh environment like high temperature, varying pH, etc. In this work, we have prepared both enzyme-based and enzyme-less graphene oxide-based biosensors for glucose detection using glucose-oxidase as enzyme and gold nanoparticles, respectively. These samples were characterized using X-ray diffraction, UV-visible spectroscopy, scanning electron microscopy, and transmission electron microscopy to confirm the successful synthesis of the working electrodes. Electrochemical measurements were performed for both the working electrodes using a 3-electrode electrochemical cell. Cyclic voltammetry curves showed the homogeneous transfer of electron on the electrodes in the scan range between -0.2V to 0.6V. The sensing measurements were performed using differential pulse voltammetry for the glucose concentration varying from 0.01 mM to 20 mM, and sensing was improved towards glucose in the presence of gold nanoparticles. Gold nanoparticles in graphene oxide nanocomposite played an important role in sensing glucose in the absence of enzyme, glucose oxidase, as evident from these measurements. The selectivity was tested by measuring the current response of the working electrode towards glucose in the presence of the other common interfering agents like cholesterol, ascorbic acid, citric acid, and urea. The enzyme-less working electrode also showed storage stability for up to 15 weeks, making it a suitable glucose biosensor.

Keywords: electrochemical, enzyme-less, glucose, gold nanoparticles, graphene oxide, nanocomposite

Procedia PDF Downloads 111
97 Surface Morphology and Wetting Behavior of the Aspidiotus spp. Scale Covers

Authors: Meril Kate Mariano, Billy Joel Almarinez Divina Amalin, Jose Isagani Janairo

Abstract:

The scale insects Aspidiotus destructor and Aspidiotus rigidus exhibit notable scale covers made of wax which provides protection against water loss and is capable to resist wetting, thus making them a desirable model for biomimetic designs. Their waxy covers enable them to infest mainly leaves of coconut trees despite the harsh wind and rain. This study aims to describe and compare the micro morphological characters on the surfaces of their scale covers consequently, how these micro structures affect their wetting properties. Scanning electron microscope was used for the surface characterization while an optical contact angle meter was employed in the wetting measurement. The scale cover of A. destructor is composed of multiple overlapping layers of wax that is arranged regularly while that of A. rigidus is composed of a uniform layer of wax with much more prominent wax ribbons irregularly arranged compared to the former. The protrusions found on the two organisms are formed by the wax ribbons that differ in arrangement with their height being A. destructor (3.57+1.29) < A. rigidus (4.23+1.22) and their density A. destructor (15+2.94) < A. rigidus (18.33+2.64). These morphological measurements could affect the contact angle (CA θ) measurement of A. destructor (102.66+9.78°) < A. rigidus (102.77 + 11.01°) wherein the assessment that the interaction of the liquid to the microstructures of the substrate is a large factor in the wetting properties of the insect scales is realized. The calculated surface free energy of A. destructor (38.47 mJ/m²) > A. rigidus (31.02 mJ/m²) shows inverse proportionality with the CA measurement. The dispersive interaction between the surface and liquid is more prevalent compared to the polar interaction for both Aspidiotus species, which was observed using the Fowkes method. The results of this study have possible applications to be a potential biomimetic design for various industries such as textiles and coatings.

Keywords: Aspidiotus spp., biomimetics, contact angle, surface characterization, wetting behavior

Procedia PDF Downloads 93
96 Environmental Degradation of Natural Resources in Broghil National Park in the High Mountains of Pakistan – Empirical Evidence From Local Community and Geoinformatics

Authors: Siddique Ullah Baig, Alisha Manzoor

Abstract:

The remotest, mountainous, and icy Broghil Valley is a high-profile protected area as a national park, which hosts one of the highest altitude permanent human settlements on the earth. This park hosts a distributed but diverse range of habitats. Due to a lack of infrastructures, higher altitudes, and harsh environmental conditions, poverty-stricken inhabitants mostly rely on its resources, causing ecological dis-balance. This study aims to investigate the environmental degradation of natural resources of the park based on empirical evidence from stakeholders and geoinformatics. The result shows that one-fourth of the park is a gently undulating basin dotted with water bodies / grass, and agricultural land and three fourth is entirely rugged with steep mountains and glaciers. There are virtually no forests as the arid cold tundra climate and high altitude prevent tree growth. Rapid three-decadal land cover changes have led to ecological disequilibrium of the park, narrowing the traditional diverse food base, decreasing the resilience of biodiversity and local livelihoods as crop-land has shifted towards fallow, alpine-grass to peat-land and snow/glacial ice area to bare-soil/rocks. The local community believes in exploiting whatever vegetation or organic material is available for use as food, fodder, and fuel. The permanent presence of the community and limited cost-effective options in the park will be a challenge forever to maintain undisturbed natural processes as the objective of a national park.

Keywords: Broghil National Park, natural resources, environmental degradation, land cover

Procedia PDF Downloads 38
95 Investigations of Bergy Bits and Ship Interactions in Extreme Waves Using Smoothed Particle Hydrodynamics

Authors: Mohammed Islam, Jungyong Wang, Dong Cheol Seo

Abstract:

The Smoothed Particle Hydrodynamics (SPH) method is a novel, meshless, and Lagrangian technique based numerical method that has shown promises to accurately predict the hydrodynamics of water and structure interactions in violent flow conditions. The main goal of this study is to build confidence on the versatility of the Smoothed Particle Hydrodynamics (SPH) based tool, to use it as a complementary tool to the physical model testing capabilities and support research need for the performance evaluation of ships and offshore platforms exposed to an extreme and harsh environment. In the current endeavor, an open-sourced SPH-based tool was used and validated for modeling and predictions of the hydrodynamic interactions of a 6-DOF ship and bergy bits. The study involved the modeling of a modern generic drillship and simplified bergy bits in floating and towing scenarios and in regular and irregular wave conditions. The predictions were validated using the model-scale measurements on a moored ship towed at multiple oblique angles approaching a floating bergy bit in waves. Overall, this study results in a thorough comparison between the model scale measurements and the prediction outcomes from the SPH tool for performance and accuracy. The SPH predicted ship motions and forces were primarily within ±5% of the measurements. The velocity and pressure distribution and wave characteristics over the free surface depicts realistic interactions of the wave, ship, and the bergy bit. This work identifies and presents several challenges in preparing the input file, particularly while defining the mass properties of complex geometry, the computational requirements, and the post-processing of the outcomes.

Keywords: SPH, ship and bergy bit, hydrodynamic interactions, model validation, physical model testing

Procedia PDF Downloads 110
94 Day Ahead and Intraday Electricity Demand Forecasting in Himachal Region using Machine Learning

Authors: Milan Joshi, Harsh Agrawal, Pallaw Mishra, Sanand Sule

Abstract:

Predicting electricity usage is a crucial aspect of organizing and controlling sustainable energy systems. The task of forecasting electricity load is intricate and requires a lot of effort due to the combined impact of social, economic, technical, environmental, and cultural factors on power consumption in communities. As a result, it is important to create strong models that can handle the significant non-linear and complex nature of the task. The objective of this study is to create and compare three machine learning techniques for predicting electricity load for both the day ahead and intraday, taking into account various factors such as meteorological data and social events including holidays and festivals. The proposed methods include a LightGBM, FBProphet, combination of FBProphet and LightGBM for day ahead and Motifs( Stumpy) based on Mueens algorithm for similarity search for intraday. We utilize these techniques to predict electricity usage during normal days and social events in the Himachal Region. We then assess their performance by measuring the MSE, RMSE, and MAPE values. The outcomes demonstrate that the combination of FBProphet and LightGBM method is the most accurate for day ahead and Motifs for intraday forecasting of electricity usage, surpassing other models in terms of MAPE, RMSE, and MSE. Moreover, the FBProphet - LightGBM approach proves to be highly effective in forecasting electricity load during social events, exhibiting precise day ahead predictions. In summary, our proposed electricity forecasting techniques display excellent performance in predicting electricity usage during normal days and special events in the Himachal Region.

Keywords: feature engineering, FBProphet, LightGBM, MASS, Motifs, MAPE

Procedia PDF Downloads 42
93 Silent Struggles: Unveiling Linguistic Insights into Poverty in Ancient Egypt

Authors: Hossam Mohammed Abdelfattah

Abstract:

In ancient Egypt, poverty, recognized as the foremost challenge, was extensively addressed in teachings, wisdom, and literary texts. These sources vividly depicted the suffering of a class deprived of life's pleasures. The ancient Egyptian language evolved to introduce terms reflecting poverty and hunger, underscoring the society's commitment to acknowledging and cautioning against this prevalent issue. Among the notable expressions, iwty.f emerged during the Middle Kingdom, symbolizing "the one without property" and signifying the destitute poor. iwty n.f traced back to the Pyramid Texts era, referred to "the one who has nothing" or simply, the poor. Another term, , iwty-sw emphasized the state of possessing nothing. rA-awy originating in the Middle Kingdom Period, initially meant "poverty and poor," expanding to signify poverty in various texts with the addition of the preposition "in," conveying strength given to the poor. During the First Intermediate Period, sny - mnt denoted going through a crisis or suffering, possibly referencing a widespread disease or plague. It encompassed meanings of sickness, pain, and anguish. The term .” sq-sn introduced in Middle Kingdom texts, conveyed the notion of becoming miserable. sp-Xsy . represented a temporal expression reflecting a period of misery or poverty, with Xsy ,indicating distress or misery. The term qsnt appearing in Middle Kingdom texts, held meanings of painful, difficult, harsh, miserable, emaciated, and in bad condition. Its feminine form, qsn denoted anxiety and turmoil. Finally, tp-qsn encapsulated the essence of misery and unhappiness. In essence, these expressions provide linguistic insights into the multifaceted experience of poverty in ancient Egypt, illustrating the society's keen awareness and efforts to address this pervasive challenge.

Keywords: poverty, poor, suffering, misery, painful, ancient Egypt

Procedia PDF Downloads 20
92 Heliport Remote Safeguard System Based on Real-Time Stereovision 3D Reconstruction Algorithm

Authors: Ł. Morawiński, C. Jasiński, M. Jurkiewicz, S. Bou Habib, M. Bondyra

Abstract:

With the development of optics, electronics, and computers, vision systems are increasingly used in various areas of life, science, and industry. Vision systems have a huge number of applications. They can be used in quality control, object detection, data reading, e.g., QR-code, etc. A large part of them is used for measurement purposes. Some of them make it possible to obtain a 3D reconstruction of the tested objects or measurement areas. 3D reconstruction algorithms are mostly based on creating depth maps from data that can be acquired from active or passive methods. Due to the specific appliance in airfield technology, only passive methods are applicable because of other existing systems working on the site, which can be blinded on most spectral levels. Furthermore, reconstruction is required to work long distances ranging from hundreds of meters to tens of kilometers with low loss of accuracy even with harsh conditions such as fog, rain, or snow. In response to those requirements, HRESS (Heliport REmote Safeguard System) was developed; which main part is a rotational head with a two-camera stereovision rig gathering images around the head in 360 degrees along with stereovision 3D reconstruction and point cloud combination. The sub-pixel analysis introduced in the HRESS system makes it possible to obtain an increased distance measurement resolution and accuracy of about 3% for distances over one kilometer. Ultimately, this leads to more accurate and reliable measurement data in the form of a point cloud. Moreover, the program algorithm introduces operations enabling the filtering of erroneously collected data in the point cloud. All activities from the programming, mechanical and optical side are aimed at obtaining the most accurate 3D reconstruction of the environment in the measurement area.

Keywords: airfield monitoring, artificial intelligence, stereovision, 3D reconstruction

Procedia PDF Downloads 94
91 Using Problem-Based Learning on Teaching Early Intervention for College Students

Authors: Chen-Ya Juan

Abstract:

In recent years, the increasing number of children with special needs has brought a lot of attention by many scholars and experts in education, which enforced the preschool teachers face the harsh challenge in the classroom. To protect the right of equal education for all children, enhance the quality of children learning, and take care of the needs of children with special needs, the special education paraprofessional becomes one of the future employment trends for students of the department of the early childhood care and education. Problem-based learning is a problem-oriented instruction, which is different from traditional instruction. The instructor first designed an ambiguous problem direction, following the basic knowledge of early intervention, students had to find clues to solve the problem defined by themselves. In the class, the total instruction included 20 hours, two hours per week. The primary purpose of this paper is to investigate the relationship of student academic scores, self-awareness, learning motivation, learning attitudes, and early intervention knowledge. A total of 105 college students participated in this study and 97 questionnaires were effective. The effective response rate was 90%. The student participants included 95 females and two males. The average age of the participants was 19 years old. The questionnaires included 125 questions divided into four major dimensions: (1) Self-awareness, (2) learning motivation, (3) learning attitudes, and (4) early intervention knowledge. The results indicated (1) the scores of self-awareness were 58%; the scores of the learning motivations was 64.9%; the scores of the learning attitudes was 55.3%. (2) After the instruction, the early intervention knowledge has been increased to 64.2% from 38.4%. (3) Student’s academic performance has positive relationship with self-awareness (p < 0.05; R = 0.506), learning motivation (p < 0.05; R = 0.487), learning attitudes (p < 0.05; R = 0.527). The results implied that although students had gained early intervention knowledge by using PBL instruction, students had medium scores on self-awareness and learning attitudes, medium high in learning motivations.

Keywords: college students, children with special needs, problem-based learning, learning motivation

Procedia PDF Downloads 123
90 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

Abstract:

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 325
89 Synthesis of Low-Cost Porous Silicon Carbide Foams from Renewable Sources

Authors: M. A. Bayona, E. M. Cordoba, V. R. Guiza

Abstract:

Highly porous carbon-based foams are used in a wide range of industrial applications, which include absorption, catalyst supports, thermal insulation, and biomaterials, among others. Particularly, silicon carbide (SiC) based foams have shown exceptional potential for catalyst support applications, due to their chemical inertness, large frontal area, low resistance to flow, low-pressure drop, as well as high resistance to temperature and corrosion. These properties allow the use of SiC foams in harsh environments with high durability. Commonly, SiC foams are fabricated from polysiloxane, SiC powders and phenolic resins, which can be costly or highly toxic to the environment. In this work, we propose a low-cost method for the fabrication of highly porous, three-dimensional SiC foams via template replica, using recycled polymeric sponges as sacrificial templates. A sucrose-based resin combined with a Si-containing pre-ceramic polymer was used as the precursor. Polymeric templates were impregnated with the precursor solution, followed by thermal treatment at 1500 °C under an inert atmosphere. Several synthesis parameters, such as viscosity and composition of the precursor solution (Si: Sucrose molar ratio), and the porosity of the template, were evaluated in terms of their effect on the morphology, composition and mechanical resistance of the resulting SiC foams. The synthesized composite foams exhibited a highly porous (50-90%) and interconnected structure, containing 30-90% SiC with a mechanical compressive strength between 0.01-0.1 MPa. The methodology employed here allowed the fabrication of foams with a varied concentration of SiC and with morphological and mechanical properties that contribute to the development of materials of high relevance in the industry, while using low-cost, renewable sources such as table sugar, and providing a recycling alternative for polymeric sponges.

Keywords: catalyst support, polymer replica technique, reticulated porous ceramics, silicon carbide

Procedia PDF Downloads 99
88 Generative Design Method for Cooled Additively Manufactured Gas Turbine Parts

Authors: Thomas Wimmer, Bernhard Weigand

Abstract:

The improvement of gas turbine efficiency is one of the main drivers of research and development in the gas turbine market. This has led to elevated gas turbine inlet temperatures beyond the melting point of the utilized materials. The turbine parts need to be actively cooled in order to withstand these harsh environments. However, the usage of compressor air as coolant decreases the overall gas turbine efficiency. Thus, coolant consumption needs to be minimized in order to gain the maximum advantage from higher turbine inlet temperatures. Therefore, sophisticated cooling designs for gas turbine parts aim to minimize coolant mass flow. New design space is accessible as additive manufacturing is maturing to industrial usage for the creation of hot gas flow path parts. By making use of this technology more efficient cooling schemes can be manufacture. In order to find such cooling schemes a generative design method is being developed. It generates cooling schemes randomly which adhere to a set of rules. These assure the sanity of the design. A huge amount of different cooling schemes are generated and implemented in a simulation environment where it is validated. Criteria for the fitness of the cooling schemes are coolant mass flow, maximum temperature and temperature gradients. This way the whole design space is sampled and a Pareto optimum front can be identified. This approach is applied to a flat plate, which resembles a simplified section of a hot gas flow path part. Realistic boundary conditions are applied and thermal barrier coating is accounted for in the simulation environment. The resulting cooling schemes are presented and compared to representative conventional cooling schemes. Further development of this method can give access to cooling schemes with an even better performance having higher complexity, which makes use of the available design space.

Keywords: additive manufacturing, cooling, gas turbine, heat transfer, heat transfer design, optimization

Procedia PDF Downloads 322
87 High Temperature Tolerance of Chironomus Sulfurosus and Its Molecular Mechanisms

Authors: Tettey Afi Pamela, Sotaro Fujii, Hidetoshi Saito, Kawaii Koichiro

Abstract:

Introduction: Organisms employ adaptive mechanisms when faced with any stressor or risk of being wiped out. This has made it possible for them to survive in harsh environmental conditions such as increasing temperature, low pH, and anoxia. Some of the mechanisms they utilize include the expression of heat shock proteins, synthesis of cryoprotectants, and anhydrobiosis. Heat shock proteins (HSPs) have been widely studied to determine their involvement in stress tolerance among various organism, of which chironomid species have been no exception. We examined the survival and expression of genes encoding five (5) heat shock proteins (HSP70, HSP67, HSP60, HSP27, and HSP23) from Chironomus sulfurosus larvae reared from 1st instar at 25°C, 30°C, 35°C, and 40°C. Results: The highest survival rate was recorded at 30°C, followed by 25°C, then 35°C. Only a small percentage of C. sulfurosus survived at 40°C (14.5%). With regards to HSPs expression, some HSPs responded to an increase in high temperature. The relative expression levels were lowest at 30°C for HSP70, HSP60, HSP27, and HSP23. At 25°C and 40°C, HSP70, HSP67, HSP60, HSP27, and HSP23 had the highest expression. At 35°C, all had the lowest expression. Discussion: The expression of heat shock proteins varies from one species to another. We designated the genes HSP 70, HSP 67, HSP 60, HSP 27, and HSP 23 genes based on transcriptome analysis of C. sulfurosus. Our study can be termed as a long-heat shock study as C. sulfurosus was reared from the first instar to the fourth instar, and this might have led to a continuous induction of HSPs at 25°C. 40°C had the lowest survival but highest HSPs expression as C. sulfurosus larvae had to utilize HSPs for sustenance. These results and future high-throughput studies at both the transcriptome and proteome level will improve the information needed to predict the future geographic distribution of these species within the context of global warming.

Keywords: chironomid, heat shock proteins, high temperature, heat shock protein expression

Procedia PDF Downloads 72
86 Faceless Women: The Blurred Image of Women in Film on and Off-Screen

Authors: Ana Sofia Torres Pereira

Abstract:

Till this day, women have been underrepresented and stereotyped both in TV and Cinema Screens all around the World. While women have been gaining a different status and finding their own voice in the work place and in society, what we see on-screen is still something different, something gender biased, something that does not show the multifaceted identities a woman might have. But why is this so? Why are we stuck on this shallow vision of women on-screen? According to several cinema industry studies, most film screenwriters in Hollywood are men. Women actually represent a very low percentage of screenwriters. So why is this relevant? Could the underrepresentation of women screenwriters in Hollywood be affecting the way women are written, and as a result, are depicted in film? Films are about stories, about people, and if these stories are continuously told through a man’s gaze, is that helping in the creation of a gender imbalance towards women? On the other hand, one of the reasons given for the low percentage of women screenwriters is: women are said to be better at writing specific genres, like dramas and comedies, and not as good writing thrillers and action films, so, as women seem to be limited in the genres they can write, they are undervalued and underrepresented as screenwriters. It seems the gender bias and stereotype isn’t saved exclusively for women on-screen, but also off-screen and behind the screen. So film appears to be a men’s world, on and off-screen, and since men seem to write the majority of scripts, it might be no wonder that women have been written in a specific way and depicted in a specific way on-screen. Also, since films are a mass communication medium, maybe this over-sexualization and stereotyping on-screen is indoctrinating our society into believing this bias is alive and well, and thus targeting women off-screen as well (ergo, screenwriters). What about at the very begging of film? In the Silent Movies and Early Talkies era, women dominated the screenwriting industry. They wrote every genre, and the majority of scripts were written by women, not men. So what about then? How were women depicted in films then? Did women screenwriters, in an era that was still very harsh on women, use their stories and their power to break stereotypes and show women in a different light, or did they carry on with the stereotype, did they continue it and standardize it? This papers aims to understand how important it is to have more working women screenwriters in order to break stereotypes regarding the image of women on and off-screen. How much can a screenwriter (male or female) influence our gaze on women (on and off-screen)?

Keywords: cinema, gender bias, stereotype, women on-screen, women screenwriters

Procedia PDF Downloads 318
85 Mixed Tetravalent Cs₂RuₘPt₁-ₘX₆ (X = Cl-, Br-) Based Vacancy-Ordered Halide Double Perovskites for Enhanced Solar Water Oxidation

Authors: Jigar Shaileshumar Halpati, Aravind Kumar Chandiran

Abstract:

Vacancy ordered double perovskites (VOPs) have been significantly attracting researchers due to their chemical structure diversity and interesting optoelectronic properties. Some VOPs have been recently reported to be suitable photoelectrodes for photoelectrochemical water-splitting reactions due to their high stability and panchromatic absorption. In this work, we systematically synthesized mixed tetravalent VOPs based on Cs₂RuₘPt₁-ₘX₆ (X = Cl-, Br-) and reported their structural, optical, electrochemical and photoelectrochemical properties. The structural characterization confirms that the mixed tetravalent site intermediates formed their own phases. The parent materials, as well as their intermediates, were found to be stable in ambient conditions for over 1 year and also showed incredible stability in harsh pH media ranging from pH 1 to pH 11. Moreover, these materials showed panchromatic absorption with onset up to 1000 nm depending upon the mixture stoichiometry. The extraordinary stability and excellent absorption properties make them suitable materials for photoelectrochemical water-splitting applications. PEC studies of these series of materials showed a high water oxidation photocurrent of 0.56 mA cm-² for Cs₂Ru₀.₅Pt₀.₅Cl₆. Fundamental investigation from photoelectrochemical reactions revealed that the intrinsic ruthenium-based VOP showed enhanced hole transfer to the electrolyte, while the intrinsic platinum-based VOP showed higher photovoltage. The mix of these end members at the tetravalent site showed a synergic effect of reduced charge transfer resistance from the material to the electrolyte and increased photovoltage, which led to increased PEC performance of the intermediate materials.

Keywords: solar water splitting, photo electrochemistry, photo absorbers, material characterization, device characterization, green hydrogen

Procedia PDF Downloads 39
84 An Audit to Look at the Management of Paediatric Peri Orbital Cellulitis in a District General Hospital, Emergency Department

Authors: Ruth Green, Samantha Milton, Rinal Desai

Abstract:

Background/Aims: Eye pain/swelling/redness is a common presentation to Barnet General Hospital (a district general hospital), pediatric emergency department, and is managed by both the pediatric and emergency teams. The management of each child differs dramatically depending on the healthcare professional who reviews them. There also appears to be confusion in diagnosis between periorbital cellulitis, pre-septal cellulitis, and orbital cellulitis. Pre septal cellulitis refers to an inflammation of the eyelids and soft tissue anterior to the orbital septum. In contrast, orbital cellulitis is a serious, rapidly progressive infection of soft tissues located posterior to the orbital septum. Pre-septal cellulitis is more prevalent and less serious than orbital cellulitis, although it may be part of a continuous spectrum if untreated. Pre-septal cellulitis should there be diagnosed and treated urgently to prevent spread to the septum. For the purpose of the audit, the term periorbital cellulitis has been used as an umbrella term for all spectrums of this infection. The audit aimed to look at, how as a whole, the department is diagnosing and managing orbital and pre-septal cellulitis. Gold Standard: Patients of the same age and diagnosis should be treated with the same medication, advice, and follow-up. Method: Data was collected retrospectively from pediatric patients ( < 18years) who attended the emergency department from June 2019 to February 2020 who had been coded as pre-septal cellulitis, periorbital cellulitis, orbital cellulitis, or eye pain/swelling/redness. Demographics, signs and symptoms, management, and follow-up were recorded for all patients with any of the diagnoses of pre-septal, periorbital, or orbital cellulitis. A Microsoft Excel spreadsheet was used to record the anonymised data. Results: There were vast discrepancies in the diagnosis, management, and follow-up of patients with periorbital cellulitis. Conclusion/Discussion: The audit concluded there is no uniform approach to managing periorbital cellulitis in Barnet General Hospital Paediatric Emergency Department. Healthcare professionals misdiagnosed conjunctivitis as periorbital cellulitis, and adequate steps did not appear to be documented on excluding red flag signs and symptoms of patients presenting. There was no consistency in follow-up, with some patients having timely phone reviews or clinical reviews for mild symptoms. Advice given by the staff was appropriate, and patients did return when symptoms got worse and were treated accordingly. Plan: Given the inconsistency, a gold standard care pathway or local easily accessible clinical guideline can be developed to help with the diagnosis and management of periorbital cellulitis. Along with this, a teaching session can be carried out for the staff of the pediatric team and emergency department to disseminate the teaching. Following the introduction of a guideline and teaching sessions, patients notes can be re-reviewed to check improvement in patient care.

Keywords: periorbital cellulitis, preseptal cellulitis, orbital cellulitis, erythematous eyelid

Procedia PDF Downloads 107
83 Vibro-Acoustic Modulation for Crack Detection in Windmill Blades

Authors: Abdullah Alnutayfat, Alexander Sutin

Abstract:

One of the most important types of renewable energy resources is wind energy which can be produced by wind turbines. The blades of the wind turbine are exposed to the pressure of the harsh environment, which causes a significant issue for the wind power industry in terms of the maintenance cost and failure of blades. One of the reliable methods for blade inspection is the vibroacoustic structural health monitoring (SHM) method which examines information obtained from the structural vibrations of the blade. However, all vibroacoustic SHM techniques are based on comparing the structural vibration of intact and damaged structures, which places a practical limit on their use. Methods for nonlinear vibroacoustic SHM are more sensitive to damage and cracking and do not need to be compared to data from the intact structure. This paper presents the Vibro-Acoustic Modulation (VAM) method based on the modulation of high-frequency (probe wave) by low-frequency loads (pump wave) produced by the blade rotation. The blade rotation alternates bending stress due to gravity, leading to crack size variations and variations in the blade resonance frequency. This method can be used with the classical SHM vibration method in which the blade is excited by piezoceramic actuator patches bonded to the blade and receives the vibration response from another piezoceramic sensor. The VAM modification of this method analyzes the spectra of the detected signal and their sideband components. We suggest the VAM model as the simple mechanical oscillator, where the parameters of the oscillator (resonance frequency and damping) are varied due to low-frequency blade rotation. This model uses the blade vibration parameters and crack influence on the blade resonance properties from previous research papers to predict the modulation index (MI).

Keywords: wind turbine blades, damaged detection, vibro-acoustic structural health monitoring, vibro-acoustic modulation

Procedia PDF Downloads 56
82 Traditional Ceramics Value in the Middle East

Authors: Abdelmessih Malak Sadek Labib

Abstract:

The Stability in harsh environments thanks to excellent electrical, mechanical and thermal properties is what ceramics are all about selected materials for many applications despite advent of new materials such as plastics and composites. However, ceramic materials have disadvantages, including brittleness. Fragility is often attributed to pottery strong covalent and ionic bonds in the ceramic body. There is still much to learn about brittle cracks in a attention to detail, hence the fragility of the ceramic and its catastrophic failure of a frequently studied topic, particularly in charging applications. One of the most commonly used ceramics for load-bearing applications such as veneers is porcelain. Porcelain is a type of traditional pottery. Traditional pottery consists mainly of three basic ingredients: clay, which gives plasticity; silica which maintains the shape and stability of the ceramic body over temperature high temperature; and feldspar affecting glazing. In traditional pottery, the inversion of quartz during cooling the process can create microcracks that act as a stress concentration centers. Consequently, subcritical crack growth is caused due to quartz inversion origins unpredictable catastrophic failure of the work of ceramic bodies when reloading. In the case of porcelain, however, this is what the mullite hypothesis says the strength of porcelain can be significantly increased with felt Interlocking of mullite needles in the ceramic body.in this way realistic assessment of the role of quartz and mullite Porcelain with a strength of is needed to grow stronger and smaller fragile porcelain. Currently,the lack of reports on Young's moduli in the literature leads to erroneous conclusions in this regard mechanical behavior of porcelain. Therefore, the current project uses the Young's modulus approach for the investigation the role of quartz and mullite on the mechanical strength of various porcelains, in addition to reducing particle size, flexural strength fractographic forces and techniques.

Keywords: materials, technical, ceramics, properties, thermal, stability, advantages

Procedia PDF Downloads 56
81 Effect of Oxidative Stress on Glutathione Reductase Activity of Escherichia coli Clinical Isolates from Patients with Urinary Tract Infection

Authors: Fariha Akhter Chowdhury, Sabrina Mahboob, Anamika Saha, Afrin Jahan, Mohammad Nurul Islam

Abstract:

Urinary tract infection (UTI) is frequently experienced by the female population where the prevalence increases with aging. Escherichia coli, one of the most common UTI causing organisms, retains glutathione defense mechanism that aids the organism to withstand the harsh physiological environment of urinary tract, host oxidative immune response and even to affect antibiotic-mediated cell death and the emergence of resistance. In this study, we aimed to investigate the glutathione reductase activity of uropathogenic E. coli (UPEC) by observing the reduced glutathione (GSH) level alteration under stressful condition. Urine samples of 58 patients with UTI were collected. Upon isolation and identification, 88% of the samples presented E. coli as UTI causing organism among which randomly selected isolates (n=9), obtained from urine samples of female patients, were considered for this study. E. coli isolates were grown under normal and stressful conditions where H₂O₂ was used as the stress-inducing agent. GSH level estimation of the isolates in both conditions was carried out based on the colorimetric measurement of 5,5'-dithio-bis (2-nitrobenzoic acid) (DTNB) and GSH reaction product using microplate reader assay. The GSH level of isolated E. coli sampled from adult patients decreased under stress compared to normal condition (p = 0.011). On the other hand, GSH production increased markedly in samples that were collected from elderly subjects (p = 0.024). A significant partial correlation between age and change of GSH level was found as well (p = 0.007). This study may help to reveal ways for better understanding of E. coli pathogenesis of UTI prevalence in elderly patients.

Keywords: Escherichia coli, glutathione reductase activity, oxidative stress, reduced glutathione (GSH), urinary tract infection (UTI)

Procedia PDF Downloads 298
80 Technological Developments to Reduce Wind Blade Turbine Levelized Cost of Energy

Authors: Pedro Miguel Cardoso Carneiro, Ricardo André Nunes Borges, João Pedro Soares Loureiro, Hermínio Maio Graça Fernandes

Abstract:

Wind energy has been exponentially growing over the last years and will allow countries to progress regarding the decarbonization objective. In parallel, the maintenance activities have also been increasing in consequence of ageing and deterioration of the wind farms. The time available for wind blade maintenance is given by the weather window that is based upon weather conditions. Most of the wind blade repair and maintenance activities require a narrow window of temperature and humidity. Due to this limitation, the current weather windows result only on approximately 35% days/year are used for maintenance, that takes place mostly during summertime. This limitation creates large economic losses in the energy production of the wind towers, since they can be inoperative or with the energy production output reduced for days or weeks due to existing damages. Another important aspect is that the maintenance costs are higher due to the high standby time and seasonality imposed on the technicians. To reduce the relevant maintenance costs of blades and energy loses some technological developments were carried out to significantly improve this reality. The focus of this activity was to develop a series of key developments to have in the near future a suspended access equipment that can operate in harsh conditions, wind rain, cold/hot environment. To this end we have identified key areas that need to be revised and require new solutions to be found; a habitat system, multi-configurable roof and floor, roof and floor interface to blade, secondary attachment solutions to the blade and to the tower. On this paper we will describe the advances produced during a national R&D project made in partnership with an end-user (Onrope) and a test center (ISQ).

Keywords: wind turbine maintenance, cost reduction, technological innovations, wind turbine blade

Procedia PDF Downloads 57
79 Multi-Functional Metal Oxides as Gas Sensors, Photo-Catalysts and Bactericides

Authors: Koyar Rane

Abstract:

Nano- to submicron size particles of narrow particle size distribution of semi-conducting TiO₂, ZnO, NiO, CuO, Fe₂O₃ have been synthesized by novel hydrazine method and tested for their gas sensing, photocatalytic and bactericidal activities and the behavior found to be enhanced when the oxides in the thin film forms, that obtained in a specially built spray pyrolysis reactor. Hydrazine method is novel in the sense, say, the UV absorption edge of the white pigment grade wide band gap (~3.2eV) TiO₂ and ZnO shifted to the visible region turning into yellowish particles, indicating modification occurring the band structure. The absorption in the visible region makes these oxides visible light sensitive photocatalysis in degrading pollutants, especially the organic dyes which otherwise increase the chemical oxygen demand of the drinking water, enabling the process feasible not under the harsh energetic UV radiation regime. The electromagnetic radiations on irradiation produce electron-hole pairs Semiconductor + hν → e⁻ + h⁺ The electron-hole pairs thus produced form Reactive Oxygen Species, ROS, on the surface of the semiconductors, O₂(adsorbed)+e⁻ → O₂• - superoxide ion OH-(surface)+h⁺ →•OH - Hydroxyl radical The ROS attack the organic material and micro-organisms. Our antibacterial studies indicate the metal oxides control the Biological Oxygen Demand (BOD) of drinking water which had beyond the safe level normally found in the municipal supply. Metal oxides in the thin film form show overall enhanced properties and the films are reusable. The results of the photodegradation and antibactericidal studies are discussed. Gas sensing studies too have been done to find the versatility of the multifunctional metal oxides.

Keywords: hydrazine method, visible light sensitive, photo-degradation of dyes, water/airborne pollutant

Procedia PDF Downloads 137
78 The Projection of Breaking Sexual Repression: Modern Women in Indian Fictions in Marathi

Authors: Suresh B. Shinde

Abstract:

The present paper examined the selective fictional works of the Indian writers in the Marathi language which reflects the gradual erosion of sexual repression of modern women characters. Furthermore, the study employed the attitudinal survey method to counter check the fictional reality of the Indian women in real life in the modern era. The Indian writers in an early stage from the pre and post-independence period pictured the women characters such as sexually suppressed and adherence to male sexual dominance. Gangadhar Gadgil a ‘Sahitya Akademi’ award winner writer in his story ‘Ek Manus’ shown that a husband, abnormally exploited her wife. G. A. Kulkarni a ‘Sahitya Akademi’ award winner writer shown that a young lady character suppressed her proposal of marriage with she loved due to the social pressure and conventions. Arvind Gokhale and Kamal Desai have also pictured lady characters who suppressed their sexual urges even they were highly educated. In the late 20th century and early 21st century, the trends of Marathi literature is dramatically changed accordingly the women fictions. Gouri Deshpande, the popular story writer, penetrates modern woman very clearly. Two lady characters are living happily together accepting revolts of society for a sexual relationship. Meghna Pethe, another well-known writer in her story, depicts a women character who was lived with her friend as live-in-relationship and enjoying the erotic sex. How so far, it was seen that the pre and post-independence women fictions are gradually changed regarding her sexually urges. This reality leads to design the survey research design in which 100 college girls and 100 middle-aged women were surveyed with sexual attitude scale and feminist identity test. It was hypothesized that the today's college girls would higher on sexual attitude and feminist identity than middle-aged women. Moreover, it was also assumed that sexual attitude and feminist identity would have a strong positive correlation. The obtained data analyzed through Students’ test and Pearson Product Moment Correlation (PPMC). The results reveal that the today's college girls are having a high level of sexual attitude and feminist identity than middle-aged women. Results also reveal that sexual attitude and feminist identity have a strongest positive correlation. How so far the survey research has provided the reality ground to the modern women in Indian fictions in Marathi literature. The findings of the research have been discussed accordingly the gender equality as well as psychological perspectives.

Keywords: sexual repression, women in Indian fictions, sexual attitude, feminist perspectives

Procedia PDF Downloads 306
77 Analysis of the Advent of Multinational Corporations in Developing Countries: Case Study of Nike Factories Expansion in Vietnam

Authors: Khue Do Phan

Abstract:

Nike has been confronted by the press with their harsh working conditions, underpayment and highly-labor intensive requirement to their manufacturing workers and hiring of underage workers in Vietnam, Nike's largest production center. To analyze this topic critically through an international relations perspective, theory of dependency will be used to criticize the notion of exploitation of resources from developed countries towards developing countries. Theory of economic liberalism will be used to support the notion private property, the free market and generally capitalism as beneficial to both developing and developed countries. Workers are mentally, physically and sexually abused in the factories. In addition to this, their working conditions consist of improper training, lack of safety equipment, exposure of chemicals (glues and pants), their average wage is below the minimum wage in their country; the workers have to work around 60 hours or more a week. Even Nike says that the conditions are regulated often to make sure the workers get a voice to have their work rights and safe working environment. The monitors come to analyze the factories but in the end talk to the employers, whom are the direct abusers to the employees. Health benefits are rarely granted to the employees; they are forced to pay their bills first then the company will reimburse them later. They would also get in trouble for using the bathroom, taking a lunch break or sick days off because this would mean it would decrease their hours of work, leading to an even lower wage and a really angry employer. Of course with the press criticizing Nike’s lack of respect for human rights and working rights, Nike has been working on policy making and implementation to deal with the abuses. Due to its large chains and a great number of outsourcing host countries, the changes that Nike wish or attempt to make have not be in effect as quickly nor spreading to all countries it holds accountable for in its outsourcing factories.

Keywords: dependency theory, economic liberalism, human rights, outsource

Procedia PDF Downloads 299
76 Transitioning Classroom Students to Working Learners: Lived Experiences of Senior High School Work Immersion Students

Authors: Rico Herrero

Abstract:

The study looked into the different lived experiences of senior high school to work immersion and how they were able to cope up in the transition stage from being classroom students into immersion students in work immersion site. The participants of the study were the ten senior high school students from Punta Integrated School. Using interview guide questions, the researchers motivated the participants to reveal their thoughts, feelings, and experiences in the interviews via video recording. The researchers utilized the qualitative research design, but the approach used was grounded theory. The findings revealed the participants’ lived experiences on how to cope or overcome the transition stage during the work immersion program. They unanimously responded to the interview questions. And based on the themes that emerged from the testimonies of the Senior High School students, the classroom learners benefited a lot from authentic learning opportunity of immersion program. Work immersion provides the students the opportunity to learn and develop their skills/ competencies related to the field of specialization. The hands-on training provides them simulation of work. They realized that theoretical learning in school is not enough to be equipped to work. Immersion program also provides venue for values and standard transformation. Senior High School students felt a high demand of self-confidence at the beginning of their race. Good thing, self-esteem of an individual helps bring out one’s potential at its best. Students find it challenging to get along with people in all ages. But, the endeavour absolutely helps them to grow maturely. Participants also realized that it’s not easy to deal with time pressure. Hence, the immersion program taught them to learn about time management. Part of the best training is to expose the learners to the harsh reality. Despite of the things that the school had taught them, still, students realized that they are not yet ready to deal with the demands of work. Furthermore, they also found out that they need to develop an interpersonal skill to improve their human relationships.

Keywords: grounded theory, lived experiences, senior high school, work immersion

Procedia PDF Downloads 121
75 Electronics Thermal Management Driven Design of an IP65-Rated Motor Inverter

Authors: Sachin Kamble, Raghothama Anekal, Shivakumar Bhavi

Abstract:

Thermal management of electronic components packaged inside an IP65 rated enclosure is of prime importance in industrial applications. Electrical enclosure protects the multiple board configurations such as inverter, power, controller board components, busbars, and various power dissipating components from harsh environments. Industrial environments often experience relatively warm ambient conditions, and the electronic components housed in the enclosure dissipate heat, due to which the enclosures and the components require thermal management as well as reduction of internal ambient temperatures. Design of Experiments based thermal simulation approach with MOSFET arrangement, Heat sink design, Enclosure Volume, Copper and Aluminum Spreader, Power density, and Printed Circuit Board (PCB) type were considered to optimize air temperature inside the IP65 enclosure to ensure conducive operating temperature for controller board and electronic components through the different modes of heat transfer viz. conduction, natural convection and radiation using Ansys ICEPAK. MOSFET’s with the parallel arrangement, IP65 enclosure molded heat sink with rectangular fins on both enclosures, specific enclosure volume to satisfy the power density, Copper spreader to conduct heat to the enclosure, optimized power density value and selecting Aluminum clad PCB which improves the heat transfer were the contributors towards achieving a conducive operating temperature inside the IP-65 rated Motor Inverter enclosure. A reduction of 52 ℃ was achieved in internal ambient temperature inside the IP65 enclosure between baseline and final design parameters, which met the operative temperature requirements of the electronic components inside the IP-65 rated Motor Inverter.

Keywords: Ansys ICEPAK, aluminium clad PCB, IP 65 enclosure, motor inverter, thermal simulation

Procedia PDF Downloads 98
74 Development of a Two-Step 'Green' Process for (-) Ambrafuran Production

Authors: Lucia Steenkamp, Chris V. D. Westhuyzen, Kgama Mathiba

Abstract:

Ambergris, and more specifically its oxidation product (–)-ambrafuran, is a scarce, valuable, and sought-after perfumery ingredient. The material is used as a fixative agent to stabilise perfumes in formulations by reducing the evaporation rate of volatile substances. Ambergris is a metabolic product of the sperm whale (Physeter macrocephatus L.), resulting from intestinal irritation. Chemically, (–)-ambrafuran is produced from the natural product sclareol in eight synthetic steps – in the process using harsh and often toxic chemicals to do so. An overall yield of no more than 76% can be achieved in some routes, but generally, this is lower. A new 'green' route has been developed in our laboratory in which sclareol, extracted from the Clary sage plant, is converted to (–)-ambrafuran in two steps with an overall yield in excess of 80%. The first step uses a microorganism, Hyphozyma roseoniger, to bioconvert sclareol to an intermediate diol using substrate concentrations up to 50g/L. The yield varies between 90 and 67% depending on the substrate concentration used. The purity of the diol product is 95%, and the diol is used without further purification in the next step. The intermediate diol is then cyclodehydrated to the final product (–)-ambrafuran using a zeolite, which is not harmful to the environment and is readily recycled. The yield of the product is 96%, and following a single recrystallization, the purity of the product is > 99.5%. A preliminary LC-MS study of the bioconversion identified several intermediates produced in the fermentation broth under oxygen-restricted conditions. Initially, a short-lived ketone is produced in equilibrium with a more stable pyranol, a key intermediate in the process. The latter is oxidised under Norrish type I cleavage conditions to yield an acetate, which is hydrolysed either chemically or under lipase action to afford the primary fermentation product, an intermediate diol. All the intermediates identified point to the likely CYP450 action as the key enzyme(s) in the mechanism. This invention is an exceptional example of how the power of biocatalysis, combined with a mild, benign chemical step, can be deployed to replace a total chemical synthesis of a specific chiral antipode of a commercially relevant material.

Keywords: ambrafuran, biocatalysis, fragrance, microorganism

Procedia PDF Downloads 176
73 The Molecular Analysis of Effect of Phytohormones and Spermidine on Tomato Growth under Biotic Stress

Authors: Rumana Keyani, Haleema Sadia, Asia Nosheen, Rabia Naz, Humaira Yasmin, Sidra Zahoor

Abstract:

Tomato is a significant crop of the world and is one of the staple foods of Pakistan. A vast number of plant pathogens from simple viruses to complex parasites cause diseases in tomatoes but fungal infection in our country is quite high. Sometimes the symptoms are too harsh destroying the crop altogether. Countries like our own with continuously increasing massive population and limited resources cannot afford such an economic loss. There is an array of morphological, genetic, biochemical and molecular processes involved in plant resistance mechanisms to biotic stress. The study of different metabolic pathways like Jasmonic acid (JA) pathways and most importantly signaling molecules like ROS/RNS and their redoxin enzymes i.e. TRX and NRX is crucial to disease management, contributing to healthy plant growth. So, improving tolerance in crop plants against biotic stresses is a dire need of our country and world as whole. In the current study, fungal pathogenic strains Alternaria solani and Rhizoctonia solani were used to inoculate tomatoes to check the defense responses of tomato plant against these pathogens at molecular as well as phenotypic level with jasmonic acid and spermidine pretreatment. All the growth parameters (root and shoot length, dry and weight root, shoot weight measured 7 days post-inoculation, exhibited that infection drastically declined the growth of the plant whereas jasmonic acid and spermidine assisted the plants to cope up with the infection. Thus, JA and Spermidine treatments maintained comparatively better growth factors. Antioxidant assays and expression analysis through real time quantitative PCR following time course experiment at 24, 48 and 72 hours intervals also exhibited that activation of JA defense genes and a polyamine Spermidine helps in mediating tomato responses against fungal infection when used alone but the two treatments combined mask the effect of each other.

Keywords: fungal infection, jasmonic acid defence, tomato, spermidine

Procedia PDF Downloads 96