Search results for: high relative accuracy
16161 Aerodynamic Design of a Light Long Range Blended Wing Body Unmanned Vehicle
Authors: Halison da Silva Pereira, Ciro Sobrinho Campolina Martins, Vitor Mainenti Leal Lopes
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Long range performance is a goal for aircraft configuration optimization. Blended Wing Body (BWB) is presented in many works of literature as the most aerodynamically efficient design for a fixed-wing aircraft. Because of its high weight to thrust ratio, BWB is the ideal configuration for many Unmanned Aerial Vehicle (UAV) missions on geomatics applications. In this work, a BWB aerodynamic design for typical light geomatics payload is presented. Aerodynamic non-dimensional coefficients are predicted using low Reynolds number computational techniques (3D Panel Method) and wing parameters like aspect ratio, taper ratio, wing twist and sweep are optimized for high cruise performance and flight quality. The methodology of this work is a summary of tailless aircraft wing design and its application, with appropriate computational schemes, to light UAV subjected to low Reynolds number flows leads to conclusions like the higher performance and flight quality of thicker airfoils in the airframe body and the benefits of using aerodynamic twist rather than just geometric.Keywords: blended wing body, low Reynolds number, panel method, UAV
Procedia PDF Downloads 59016160 A Comparative Analysis of the Indoor Thermal Environment of a Room with and without Transitional Space or Threshold in Traditional Row Houses Adjacent to a Narrow Alley 'Rupchan Lane' in Old Dhaka, Bangladesh
Authors: Fatema Tasmia, Brishti Majumder, Atiqur Rahman
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Attaining appropriate thermal comfort conditions in a place where the climate is hot and humid can be perplexing. Especially, when it resides at a congested place like old Dhaka Bangladesh, the provision of giving cross ventilation and building with proper orientation is quite difficult. This paper aims to investigate the indoor thermal environment of a room with and without transitional space or threshold in traditional row houses adjacent to a narrow alley of old Dhaka through field measurements. Transitional spaces are the part of buildings which are used for semi-outdoor household activities, social gathering and it is also proved to provide an indoor thermal effect. The field study was conducted by collecting thermal data (temperature, humidity and airflow) respectively, among the outdoor narrow alley, transitional space and adjacent indoor. This east-west elongated alley has an average width of 2.13 meter (varies from 1.5 to 2.6 meter) holding row houses on both sides. Among different aspects of thermal environment, the study of this paper is based on the analysis of temperature of corresponding cases. Other aspects and their variables were considered as constant (especially material) for accuracy and avoidance of confusion. This study focuses on the outcome that can ultimately contribute to the configuration of row houses with transitional spaces and in its relation to the adjacent outdoor space while achieving thermal comfort.Keywords: alley, Old-Dhaka, row houses, temperature, thermal comfort, threshold, transitional space
Procedia PDF Downloads 19216159 Valence and Arousal-Based Sentiment Analysis: A Comparative Study
Authors: Usama Shahid, Muhammad Zunnurain Hussain
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This research paper presents a comprehensive analysis of a sentiment analysis approach that employs valence and arousal as its foundational pillars, in comparison to traditional techniques. Sentiment analysis is an indispensable task in natural language processing that involves the extraction of opinions and emotions from textual data. The valence and arousal dimensions, representing the intensity and positivity/negativity of emotions, respectively, enable the creation of four quadrants, each representing a specific emotional state. The study seeks to determine the impact of utilizing these quadrants to identify distinct emotional states on the accuracy and efficiency of sentiment analysis, in comparison to traditional techniques. The results reveal that the valence and arousal-based approach outperforms other approaches, particularly in identifying nuanced emotions that may be missed by conventional methods. The study's findings are crucial for applications such as social media monitoring and market research, where the accurate classification of emotions and opinions is paramount. Overall, this research highlights the potential of using valence and arousal as a framework for sentiment analysis and offers invaluable insights into the benefits of incorporating specific types of emotions into the analysis. These findings have significant implications for researchers and practitioners in the field of natural language processing, as they provide a basis for the development of more accurate and effective sentiment analysis tools.Keywords: sentiment analysis, valence and arousal, emotional states, natural language processing, machine learning, text analysis, sentiment classification, opinion mining
Procedia PDF Downloads 10516158 Comprehensive Feature Extraction for Optimized Condition Assessment of Fuel Pumps
Authors: Ugochukwu Ejike Akpudo, Jank-Wook Hur
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The increasing demand for improved productivity, maintainability, and reliability has prompted rapidly increasing research studies on the emerging condition-based maintenance concept- Prognostics and health management (PHM). Varieties of fuel pumps serve critical functions in several hydraulic systems; hence, their failure can have daunting effects on productivity, safety, etc. The need for condition monitoring and assessment of these pumps cannot be overemphasized, and this has led to the uproar in research studies on standard feature extraction techniques for optimized condition assessment of fuel pumps. By extracting time-based, frequency-based and the more robust time-frequency based features from these vibrational signals, a more comprehensive feature assessment (and selection) can be achieved for a more accurate and reliable condition assessment of these pumps. With the aid of emerging deep classification and regression algorithms like the locally linear embedding (LLE), we propose a method for comprehensive condition assessment of electromagnetic fuel pumps (EMFPs). Results show that the LLE as a comprehensive feature extraction technique yields better feature fusion/dimensionality reduction results for condition assessment of EMFPs against the use of single features. Also, unlike other feature fusion techniques, its capabilities as a fault classification technique were explored, and the results show an acceptable accuracy level using standard performance metrics for evaluation.Keywords: electromagnetic fuel pumps, comprehensive feature extraction, condition assessment, locally linear embedding, feature fusion
Procedia PDF Downloads 12216157 The Effect of Acute Toxicity and Thyroid Hormone Treatments on Hormonal Changes during Embryogenesis of Acipenser persicus
Authors: Samaneh Nazeri, Bagher Mojazi Amiri, Hamid Farahmand
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Production of high quality fish eggs with reasonable hatching rate makes a success in aquaculture industries. It is influenced by the environmental stimulators and inhibitors. Diazinon is a widely-used pesticide in Golestan province (Southern Caspian Sea, North of Iran) which is washed to the aquatic environment (3 mg/L in the river). It is little known about the effect of this pesticide on the embryogenesis of sturgeon fish, the valuable species of the Caspian Sea. Hormonal content of the egg is an important factor to guaranty the successful passes of embryonic stages. In this study, the fate of Persian sturgeon embryo to 24, 48, 72, and 96-hours exposure of diazinon (LC50 dose) was tested. Also, the effect of thyroid hormones (T3 and T4) on these embryos was tested concurrently or separately with diazinon LC 50 dose. Fertilized eggs are exposed to T3 (low dose: 1 ng/ml, high dose: 10 ng/ml), T4 (low dose: 1 ng/ml, high dose: 10 ng/ml). Six eggs were randomly selected from each treatment (with three replicates) in five developmental stages (two cell- division, neural, heart present, heart beaten, and hatched larvae). The possibility of changing T3, T4, and cortisol contents of the embryos were determined in all treated groups and in every mentioned embryonic stage. The hatching rate in treated groups was assayed at the end of the embryogenesis to clarify the effect of thyroid hormones and diazinon. The results indicated significant differences in thyroid hormone contents, but no significant differences were recognized in cortisol levels at various early life stages of embryos. There was also significant difference in thyroid hormones in (T3, T4) + diazinon treated embryos (P˂0.05), while no significant difference between control and treatments in cortisol levels was observed. The highest hatching rate was recorded in HT3 treatment, while the lowest hatching rate was recorded for diazinon LC50 treatment. The result confirmed that Persian sturgeon embryo is less sensitive to diazinon compared to teleost embryos, and thyroid hormones may increase hatching rate even in the presence of diazinon.Keywords: Persian sturgeon, diazinon, thyroid hormones, cortisol, embryo
Procedia PDF Downloads 30616156 Transcriptomic Analysis of Fragrant Rice Reveals the Involvement of Post-transcriptional Regulation in Response to Zn Foliar Application
Authors: Muhammad Imran, Sarfraz Shafiq, Xiangru Tang
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Alternative splicing (AS) is an important post-transcriptional regulatory mechanism to generate transcripts variability and proteome diversity in plants. Fragrant rice (Oryza sativa L.) has a high economic and nutritional value, and the application of micronutrients regulate 2-acetyl-1-pyrroline (2-AP) production, which is responsible for aroma in fragrant rice. However, no systematic investigation of AS events in response to micronutrients (Zn) has been performed in fragrant rice. Furthermore, the post-transcriptional regulation of genes involved in 2-AP biosynthesis is also not known. In this study, a comprehensive analysis of AS events under two gradients of Zn treatment in two different fragrant rice cultivars (Meixiangzhan-2 and Xiangyaxiangzhan) was performed. A total of 386 and 598 significant AS events were found in Meixiangzhan-2 treated with low and high doses of Zn, respectively. In Xiangyaxiangzhan, a total of 449 and 598 significant AS events were found in low and high doses of Zn, respectively. Go analysis indicated that these genes were highly enriched in physiological processes, metabolism, and cellular process in both cultivars. However, genotype and dose-dependent AS events were also detected in both cultivars. By comparing differential AS (DAS) events with differentially expressed genes (DEGs), we found a weak overlap among DAS and DEGs in both fragrant rice cultivars, indicating that only a few genes are post-transcriptionally regulated in response to Zn treatment. We further report that Zn differentially regulates the expression of 2-AP biosynthesis-related genes in both cultivars, and Zn treatment altered the editing frequency of SNPs in the genes involved in 2-AP biosynthesis. Finally, we showed that epigenetic modifications associated with active gene transcription are generally enriched over 2-AP biosynthesis-related genes. Taken together, our results provide evidence of the post-transcriptional gene regulation in fragrant rice in response to Zn treatment and highlight that the 2-AP biosynthesis pathway may also be post-transcriptionally regulated through epigenetic modifications. These findings will serve as a cornerstone for further investigation to understand the molecular mechanisms of 2-AP biosynthesis in fragrant rice.Keywords: fragrant rice, 2-acetyl-1-pyrroline, gene expression, zinc, alternative splicing, SNPs
Procedia PDF Downloads 11716155 Investigation of Unusually High Ultrasonic Signal Attenuation in Water Observed in Various Combinations of Pairs of Lead Zirconate Titanate Pb(ZrxTi1-x)O3 (PZT) Piezoelectric Ceramics Positioned Adjacent to One Another Separated by an Intermediate Gap
Authors: S. M. Mabandla, P. Loveday, C. Gomes, D. T. Maiga, T. T. Phadi
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Lead zirconate titanate (PZT) piezoelectric ceramics are widely used in ultrasonic applications due to their ability to effectively convert electrical energy into mechanical vibrations and vice versa. This paper presents a study on the behaviour of various combinations of pairs of PZT piezoelectric ceramic materials positioned adjacent to each other with an intermediate gap submerged in water, where one piezoelectric ceramic material is excited by a cyclic electric field with constant frequency and amplitude displacement. The transmitted ultrasonic sound propagates through the medium and is received by the PZT ceramic at the other end, the ultrasonic sound signal amplitude displacement experiences attenuation during propagation due to acoustic impedance. The investigation focuses on understanding the causes of extremely high amplitude displacement attenuation that have been observed in various combinations of piezoelectric ceramic pairs that are submerged in water arranged in a manner stipulated earlier. by examining various combinations of pairs of these piezoelectric ceramics, their physical, electrical, and acoustic properties, and behaviour and attributing them to the observed significant signal attenuation. The experimental setup involves exciting one piezoelectric ceramic material at one end with a burst square cyclic electric field signal of constant frequency, which generates a burst of ultrasonic sound that propagates through the water medium to the adjacent piezoelectric ceramic at the other end. Mechanical vibrations of a PZT piezoelectric ceramic are measured using a double-beam laser Doppler vibrometer to mimic the incident ultrasonic waves generated and received ultrasonic waves on the other end due to mechanical vibrations of a PZT. The measured ultrasonic sound wave signals are continuously compared to the applied cyclic electric field at both ends. The impedance matching networks are continuously tuned at both ends to eliminate electromechanical impedance mismatch to improve ultrasonic transmission and reception. The study delves into various physical, electrical, and acoustic properties of the PZT piezoelectric ceramics, such as the electromechanical coupling factor, acoustic coupling, and elasticity, among others. These properties are analyzed to identify potential factors contributing to the unusually high acoustic impedance in the water medium between the ceramics. Additionally, impedance-matching networks are investigated at both ends to offset the high signal attenuation and improve overall system performance. The findings will be reported in this paper.Keywords: acoustic impedance, impedance mismatch, piezoelectric ceramics, ultrasonic sound
Procedia PDF Downloads 8216154 Roles of Lysine-63-Linked Ubiquitination in Cell Decision Fate between Cell Proliferation and Apoptosis
Authors: Chargui Abderrahman, Nehdi Afef , BelaïD Amine , Djerbi Nadir, Tauc Michel, Hofman Paul, Mograbi Baharia, El May MichèLe
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K63-linked ubiquitination — i.e. conjugation of a chain of ubiquitins (Ub) linked through lys63 — has emerged as a key mechanism regulating signalling transduction pathways. Although critical, very little information is currently available about how subversion of K63 ubiquitination might contribute to cancers and inflammatory diseases. The present study provides the first evidence that Cadmium (Cd), a widespread environmental carcinogen and toxicant, is a powerful activator of K63 ubiquitination. Indeed, Cd induces accumulation of K63 polyUb proteins. Importantly, Cd-induced ubiquitination does not stem on oxidative damage or proteasome impairment. Rather, we demonstrate that Cd not only activates K63 ubiquitination but also amplifies their accumulation by overloading the capacity of autophagy pathway. At molecular level, Cd-induced ubiquitination is correlated with stabilization of HIF-1 and the activation of NF-B, two transcription factors. Strikingly, prolonged cell exposure to high Cd concentrations induces an exaggerated K63 ubiquitination that fosters aggresome formation, thus precluding these proteins from interacting with their downstream nuclear targets. We therefore propose that the aberrant activation of K63 ubiquitination by the carcinogen Cadmium could promote cell proliferation and inflammation at low levels while high levels committed cell to death.Keywords: cadmium, environmental exposure, Lysine-63-ubiquitination, kidney, apoptosis, proliferation, autophagy
Procedia PDF Downloads 21416153 Effects of Tiliacora triandra Leaf Water Extract in High-Fat Diet Leaf Water
Authors: Urarat Nanna, Jarinyaporn Naowaboot
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Tiliacora triandra (T. triandra) is traditional Southeast Asian medicine and widely used in the cuisines of northeast Thailand and Laos. It has been used as antipyretic, detoxication agent, antiinflammation. But the activity of T. triandra leaf water extract (TTW) in the regulation of metabolic syndrome is still little known. In this study, we evaluated the effects of TTW in high-fat diet (HFD)-induced obese mice. Male ICR mice were induced to be obese by HFD feeding (45 kcal% lard fat) for 12 weeks. During the last 6 weeks of diet feeding, the obese mice were treated with TTW at 250 and 500 mg/kg/day. The biochemical parameters and histology analysis were measured at the end of treatment period. After 6 weeks of TTW treatment, the hyperglycemia, hyperinsulinemia, hyperleptinemia and hyperlipidemia were significantly decreased. Hepatic lipid accumulation and adipocyte hypertrophy were also reduced. Serum adiponectin was increased in TTW-treated obese mice. TTW treatment could reduce the malondialdehyde in serum and liver tissue. Furthermore, the elevated serum inflammatory cytokines, tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 were reduced (MCP-1) by TTW. These results suggest that T. triandra leaf is a beneficial plant in alleviating hyperglycemia, hyperlipidemia, oxidative stress and inflammation in the obese condition induced by HFD.Keywords: Tiliacora triandra, insulin resistance, hyperlipidemia, oxidative stress
Procedia PDF Downloads 21716152 Preparation of Zno/Ag Nanocomposite and Coating on Polymers for Anti-Infection Biomaterial Application
Authors: Babak Sadeghi, Parisa Ghayomipour
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ZnO/Ag nanocomposites coated with polyvinyl chloride (PVC) were prepared by chemical reduction method, for anti-infection biomaterial application. There is a growing interest in attempts in using biomolecular as the templates to grow inorganic nanocomposites in controlled morphology and structure. By optimizing the experiment conditions, we successfully fabricated high yield of ZnO/Ag nanocomposite with full coverage of high-density polyvinyl chloride (PVC) coating. More importantly, ZnO/Ag nanocomposites were shown to significantly inhibit the growth of S. aureus in solution. It was further shown that ZnO/Ag nanocomposites induced thiol depletion that caused death of S. aureus. The coatings were fully characterized using techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Most importantly, compared to uncoated metals, the coatings on PVC promoted healthy antibacterial activity. Importantly, compared to ZnO-Ag -uncoated PVC, the ZnO/Ag nanocomposites coated was approximately triplet more effective in preventing bacteria attachment. The result of Thermal Gravimetric Analysis (TGA) indicates that, the ZnO/Ag nanocomposites are chemically stable in the temperature range from 50 to 900 ºC. This result, for the first time, demonstrates the potential of using ZnO/Ag nanocomposites as a coating material for numerous anti-bacterial applications.Keywords: nanocomposites, antibacterial activity, scanning electron microscopy (SEM), x-ray diffraction (XRD)
Procedia PDF Downloads 47716151 Development of Non-Point Pollutants Removal Equipments Using Media with Bacillus sp.
Authors: Han-Seul Lee, Min-Koo Kang, Sang-Ill Lee
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This study was conducted to reduce runoff by rainwater infiltration facility using attached growth with Bacillus sp., which are reported to remove nitrogen and phosphorus, as well as organic matter effectively. This study was investigated non-point pollutants removal efficiency of organic, nitrogen, and phosphorus in column using the media attached growth with Bacillus sp. To compare attached growth with bacillus sp. and detached media, two columns filled with perlite, zeolite, vermiculite, pumice, peat-moss was installed. In A column (attached growth with bacillus sp.), in case of infiltration velocity 30 mm/hr in high concentration of influent, it showed the removal efficiency (after aging term) is SS (suspended solid) 85.8±1.2 %, T-P (total phosphorus) 67.0±8.1 %, T-N (total nitrogen) 66.0±4.9 %, COD (chemical oxygen demand) 73.6±2.9 %, NH4+-N 72.7±3.0 %. In B column (detached media), in case of infiltration velocity 30 mm/hr in high concentration of influent, it showed the removal efficiency (after aging term) is SS 86.0±2.2 %, T-P 62.5±11.3 %, T-N 53.3±3.9 %, COD 34.6±3.7 %, NH4+-N 61.5±2.8 %. Removal efficiency of A column is better than B column. As the result from this study, using media with Bacillus sp. can improve an effective removal of non-point source pollutants.Keywords: non-point source pollutants, Bacillus sp., rainwater, infiltration facility
Procedia PDF Downloads 33016150 Integrating Eucalyptus Bark Valorization and Enzymatic Biopolymer Recovery for the Sustainable Production of Polyhydroxybutyrate
Authors: João Matias, T. Rodrigues, C.A.V. Torres, S. Marques, F. Gírio, M.A.M. Reis, F. Freitas
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To evaluate the potential of eucalyptus bark enzymatic hydrolysate as a sole feedstock to produce the bioplastic polyhydroxybutyrate, P(3HB), by Burkholderia thailandensis DSM 13276, three hydrolysate samples with distinct physical and chemical characteristics were analyzed and used in bioreactor cultivation assays to assess how substrate variability impacts P(3HB) production and properties. High glucose concentrations (>80 g/L) and elevated molar C/N ratios (160.7), associated with high ammonium content (0.73 g/L), promoted cell growth (CDW = 9.48 g/L) at the expense of P(3HB) accumulation (19 wt%). In contrast, lower glucose levels (~20 g/L) and reduced C/N ratios (41.5) enhanced P(3HB) accumulation (60 wt%), yielding 4.6 g/L of polymer with a volumetric productivity of 1.36 g/(L•day) and a sugar-to-polymer conversion yield of 0.19 g/g. P(3HB) was extracted using both enzymatic and solvent-based methods. The enzymatic method, employing Alcalase under mild conditions, achieved 96% recovery efficiency with exceptional purity (100 ± 3%), producing fine P(3HB) granules, while the chloroform-based method yielded aggregated clumps due to the fast precipitation of the biopolymer in cold ethanol. FTIR analysis confirmed the chemical structure of P(3HB) in all samples, with characteristic peaks for C–H and C=O stretching vibrations closely matching literature-reported spectra. The extracted biopolymer had molecular weight values between 2.77×10⁵ and 6.30×10⁵ Da, with polydispersity indices between 1.57 and 2.10. The thermal analysis showed that the produced P(3HB) exhibited melting temperatures of 170-175 ºC, and degradation temperatures between 280 ºC and 297 ºC, all aligning with commercial P(3HB) standards. These findings highlight eucalyptus bark as a cost-effective and sustainable feedstock to produce the bioplastic P(3HB), particularly when substrate composition is optimized. The study underscores the feasibility of integrating renewable feedstocks with green recovery methods, namely, enzymatic extraction, to develop high-quality bioplastics and advancing in the goals of a circular bioeconomy.Keywords: alcalase, burkholderia thailandensis DSM 13276, eucalyptus bark, Polyhydroxybutyrate
Procedia PDF Downloads 016149 Revisiting the Historical Narratives of the Old Churches in Albay, Bikol Region, Philippines
Authors: Ruby Ann L. Ayo
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As cultural heritage reflects the historical origin of a certain group of people, it reveals their customs, traits, beliefs, practices and even values they hold on for years. One of the tangible examples of cultural heritage is the physical structures including the old churches. The study looked-into the existing historical narratives of the century Old Catholic churches in the Province of Albay, Bikol Region, Philippines: NuestraSeñora de Salvacion in Joroan, Tiwi, Albay; the Our Lady of the Gate in Daraga, Albay; the San Juan de Bautista in Tabaco City and the St. John the Baptist in Camalig, Albay. The historical narratives were analysed in terms of validity and reliability of the secondary documents with reference to the elements of history revealing consistency and adequacy of historical facts. The contents were examined using a modified Checklist of Historical Documents. The historical narratives were likewise submitted to the content expert for validation as regards historical authenticity and accuracy. The contents of the narratives were scrutinized according to the following codes: (1.1) the Patron Saints;(1.2) factors that paved to their constructions; (1.3) the people responsible for their constructions; (1.4) the misconceptions about their constructions; and (1.5) their contributions to Bikol heritage. Based on the codes, themes were identified as: (2.1) Marian Devotees and Christ-centered Patron Saints; (2.2) geographical, socio-political and cultural factors; (2.3) church and government officials; (2.4) misconceptions on the dates of constructions and original sites; and (2.5) popular pilgrim sites and well-admired architectural designs.Keywords: historical narratives, old churches, cultural heritage, historical validity and reliability, elements of history
Procedia PDF Downloads 30116148 A Mixed Integer Programming Model for Optimizing the Layout of an Emergency Department
Authors: Farhood Rismanchian, Seong Hyeon Park, Young Hoon Lee
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During the recent years, demand for healthcare services has dramatically increased. As the demand for healthcare services increases, so does the necessity of constructing new healthcare buildings and redesigning and renovating existing ones. Increasing demands necessitate the use of optimization techniques to improve the overall service efficiency in healthcare settings. However, high complexity of care processes remains the major challenge to accomplish this goal. This study proposes a method based on process mining results to address the high complexity of care processes and to find the optimal layout of the various medical centers in an emergency department. ProM framework is used to discover clinical pathway patterns and relationship between activities. Sequence clustering plug-in is used to remove infrequent events and to derive the process model in the form of Markov chain. The process mining results served as an input for the next phase which consists of the development of the optimization model. Comparison of the current ED design with the one obtained from the proposed method indicated that a carefully designed layout can significantly decrease the distances that patients must travel.Keywords: Mixed Integer programming, Facility layout problem, Process Mining, Healthcare Operation Management
Procedia PDF Downloads 34516147 Lightweight Concrete Fracture Energy Derived by Inverse Analysis
Authors: Minho Kwon, Seonghyeok Lee, Wooyoung Jung
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In recent years, with increase of construction of skyscraper structures, the study of concrete materials to improve their weight and performance has been emerging as a key of research area. Typically, the concrete structures has disadvantage of increasing the weight due to its mass in comparison to the strength of the materials. Therefore, in order to improve such problems, the light-weight aggregate concrete and high strength concrete materials have been studied during the past decades. On the other hand, the study of light-weight aggregate concrete materials has lack of data in comparison to the concrete structure using high strength materials, relatively. Consequently, this study presents the performance characteristics of light-weight aggregate concrete materials due to the material properties and strength. Also, this study conducted the experimental tests with respect to normal and lightweight aggregate materials, in order to indentify the tensile crack failure of the concrete structures. As a result, the Crack Mouth Opening Displacement (CMOD) from the experimental tests was constructed and the fracture energy using inverse problem analysis was developed from the force-CMOD relationship in this study, respectively.Keywords: lightweight aggregate concrete, crack mouth opening displacement, inverse analysis, fracture energy
Procedia PDF Downloads 36116146 Assortative Education and Working Arrangement among Married Couples in Indonesia
Authors: Ratu Khabiba, Qisha Quarina
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This study aims to analyse the effect of married couples’ assortative educational attainments on the division of economic activities among themselves in the household. This study contributes to the literature on women’s participation in employment, especially among married women, to see whether the traditional values about gender roles in the household still continue to shape the employment participation among married women in Indonesia, despite increasing women’s human capital through education. This study utilizes the Indonesian National Socioeconomic Survey (SUSENAS) 2016 and estimates the results using the multinomial logit model. Our results show that compared to high-educated educational homogamy couples, educational heterogamy couples, especially hypergamy, have a higher probability of being a single-worker type. Moreover, the high-educated educational homogamy couples have the highest probability of being a dual-worker type. Thus, we found evidence that the traditional values of gender role segregation seem to still play a significant role in married women’s employment decision in Indonesia, particularly for couples’ with educational heterogamy and low-educated educational homogamy couples.Keywords: assortative education, dual-worker, hypergamy, homogamy, traditional values, women labor participation
Procedia PDF Downloads 12616145 Catalytic Pyrolysis of Sewage Sludge for Upgrading Bio-Oil Quality Using Sludge-Based Activated Char as an Alternative to HZSM5
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Due to the concerns about the depletion of fossil fuel sources and the deteriorating environment, the attempt to investigate the production of renewable energy will play a crucial role as a potential to alleviate the dependency on mineral fuels. In this respect, biofuels are measured as a vital nominee for national energy security and energy sustainability. Sewage sludge (SS), as an alternative source of renewable energy with a complex composition, is a major waste generated during wastewater treatment. Stricter legislation is continuously refining the requirements for the level of removal of various pollutants in treated water, causing continuous growth of sludge production, which has become a global challenge. In general, there are two main procedures for dealing with SS: incineration and landfill. However, there are a variety of limitations in these options (e.g., production of greenhouse gases and restrictive environmental regulations) in regard to negative social and economic impacts. Pyrolysis is a feasible and cost-effective technology that can simultaneously tackle boundaries concerning the current disposal routes while retrieving bioenergy. Pyrolysis of SS has drawn vigorous interest in research due to the ability of high mass yield of pyrolytic liquid production. Nonetheless, the presence of high molecular weight hydrocarbons and oxygenated- and nitrogenated compounds poses a considerable challenge. In this context, catalytic pyrolysis is another attainable route in order to upgrade the bio-oil quality. Among different catalysts (i.e., zeolites) studied for sewage sludge pyrolysis, activated chars are eco-friendly and low-cost alternatives. The beneficial features comprise comparatively large surface area, long-term stability, and enriched surface functional groups. In light of these premises, this research attempts to investigate the catalytic pyrolysis of sewage sludge with a high-performance sludge-based activated char in contrast to HZSM5 from a theoretical and experimental point of view.Keywords: catalytic pyrolysis, sewage sludge, char, HZSM5, bio-oil.
Procedia PDF Downloads 5616144 Fatigue Influence on the Residual Stress State in Shot Peened Duplex Stainless Steel
Authors: P. D. Pedrosa, J. M. A. Rebello, M. P. Cindra Fonseca
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Duplex stainless steels (DSS) exhibit a biphasic microstructure consisting of austenite and delta ferrite. Their high resistance to oxidation, and corrosion, even in H2S containing environments, allied to low cost when compared to conventional stainless steel, are some properties which make this material very attractive for several industrial applications. However, several of these industrial applications imposes cyclic loading to the equipments and in consequence fatigue damage needs to be a concern. A well-known way of improving the fatigue life of a component is by introducing compressive residual stress in its surface. Shot peening is an industrial working process which brings the material directly beneath component surface in a high mechanical compressive state, so inhibiting fatigue crack initiation. However, one must take into account the fact that the cyclic loading itself can reduce and even suppress these residual stresses, thus having undesirable consequences in the process of improving fatigue life by the introduction of compressive residual stresses. In the present work, shot peening was used to introduce residual stresses in several DSS samples. These were thereafter submitted to three different fatigue regimes: low, medium and high cycle fatigue. The evolution of the residual stress during loading were then examined on both surface and subsurface of the samples. It was used the DSS UNS S31803, with microstructure composed of 49% austenite and 51% ferrite. The treatment of shot peening was accomplished by the application of blasting in two Almen intensities of 0.25 and 0.39A. The residual stresses were measured by X-ray diffraction using the double exposure method and a portable equipment with CrK radiation and the (211) diffracting plane for the austenite phase and the (220) plane for the ferrite phase. It is known that residual stresses may arise when two regions of the same material experienced different degrees of plastic deformation. When these regions are separated in respect to each other on a scale that is large compared to the material's microstructure they are called macro stresses. In contrast, microstresses can largely vary over distances which are small comparable to the scale of the material's microstructure and must balance zero between the phases present. In the present work, special attention will be paid to the measurement of residual microstresses. Residual stress measurements were carried out in test pieces submitted to low, medium and high-cycle fatigue, in both longitudinal and transverse direction of the test pieces. It was found that after shot peening, the residual microstress is tensile in the austenite and compressive in the ferrite phases. It was hypothesized that the hardening behavior of the austenite after shot peening was probably due to its higher nitrogen content. Fatigue cycling can effectively change this stress state but this effect was found to be dependent of the shot peening intensity was well as the fatigue range.Keywords: residual stresses, fatigue, duplex steel, shot peening
Procedia PDF Downloads 23416143 Suitability of the Sport Motivation Scale–II for Use in Jr. High Physical Education: A Confirmatory Factor Analysis
Authors: Keven A. Prusak, William F. Christensen, Zack Beddoes
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Background: For more than a decade, the Sport Motivation Scale (SMS) has been used to measure contextual motivation across a variety of sporting and physical education (PE) settings but not without criticism as to its tenability. Consequently, a new version of the sport motivation scale (SMS-II) was created to address certain weakness of the original SMS. Purpose: The purpose of this study is to assess the suitability of the SMS-II in the secondary PE setting. Methods: Three hundred and twenty (204 females, and 116 males; grades 7-9) completed the 18-item, six-subscale SMS-II at the end of a required PE class. Factor means, standard deviations, and correlations were calculated and further examined via confirmatory factor analysis (CFA). Model parameters were estimated maximum likelihood function. Results: Results indicate that participants held generally positive perceptions toward PE as a context (more so for males than females). Reliability analysis yielded adequate alphas (rα = 0.71 to 0.87, Mα = 0.78) with the exception of the AM subscale (αAM = .64). Correlation analysis indicated some support for the SIMPLEX pattern, but distal ends of the motivation continuum displayed no relationship. CFA yielded robust fit indices to the proposed structure of the SMS-II for PE. A small but significant variance across genders was noted and discussed. Conclusions: In all, the SMS-II suitably accesses PE context-specific motivational indices within Jr. High PE.Keywords: motivation, self-determination theory, physical education, confirmatory factor analysis
Procedia PDF Downloads 33416142 Assessment of cellulase and xylanase Production by chryseobacterium sp. Isolated from Decaying Biomass in Alice, Eastern Cape, South Africa
Authors: A. Nkohla, U. Nwodo, L. V. Mabinya, A. I. Okoh
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A potential source for low-cost production of value added products is the utilization of lignocellulosic materials. However, the huddle needing breaching would be the dismantlement of the complex lignocellulosic structure as to free sugar base therein. the current lignocellosic material treatment process is expensive and not eco-friendly hence, the advocacy for enzyme based technique which is both cheap and eco-friendly is highly imperative. Consequently, this study aimed at the screening of cellulose and xylan degrading bacterial strain isolated from decaying sawdust samples. This isolate showed high activity for cellulase and xylanase when grown on carboxymethyl cellulose and birtchwood xylan as the sole carbon source respectively. The 16S rDNA nucleotide sequence of the isolate showed 98% similarity with that of Chryseobacterium taichungense thus, it was identified as a Chryseobacterium sp. Optimum culture conditions for cellulase and xylanase production were medium pH 6, incubation temperature of 25 °C at 50 rpm and medium pH 6, incubation temperature of 25 °C at 150 rpm respectively. The high enzyme activity obtained from this bacterial strain portends it as a good candidate for industrial use in the degradation of complex biomass for value added products.Keywords: lignocellulosic material, chryseobacterium sp., submerged fermentation, cellulase, xylanase
Procedia PDF Downloads 31516141 A Boundary-Fitted Nested Grid Model for Modeling Tsunami Propagation of 2004 Indonesian Tsunami along Southern Thailand
Authors: Fazlul Karim, Esa Al-Islam
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Many problems in oceanography and environmental sciences require the solution of shallow water equations on physical domains having curvilinear coastlines and abrupt changes of ocean depth near the shore. Finite-difference technique for the shallow water equations representing the boundary as stair step may give inaccurate results near the coastline where results are of greatest interest for various applications. This suggests the use of methods which are capable of incorporating the irregular boundary in coastal belts. At the same time, large velocity gradient is expected near the beach and islands as water depth vary abruptly near the coast. A nested numerical scheme with fine resolution is the best resort to enhance the numerical accuracy with the least grid numbers for the region of interests where the velocity changes rapidly and which is unnecessary for the away of the region. This paper describes the development of a boundary fitted nested grid (BFNG) model to compute tsunami propagation of 2004 Indonesian tsunami in Southern Thailand coastal waters. In this paper, we develop a numerical model employing the shallow water nested model and an orthogonal boundary fitted grid to investigate the tsunami impact on the Southern Thailand due to the Indonesian tsunami of 2004. Comparisons of water surface elevation obtained from numerical simulations and field measurements are made.Keywords: Indonesian tsunami of 2004, Boundary-fitted nested grid model, Southern Thailand, finite difference method
Procedia PDF Downloads 44616140 From Equations to Structures: Linking Abstract Algebra and High-School Algebra for Secondary School Teachers
Authors: J. Shamash
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The high-school curriculum in algebra deals mainly with the solution of different types of equations. However, modern algebra has a completely different viewpoint and is concerned with algebraic structures and operations. A question then arises: What might be the relevance and contribution of an abstract algebra course for developing expertise and mathematical perspective in secondary school mathematics instruction? This is the focus of this paper. The course Algebra: From Equations to Structures is a carefully designed abstract algebra course for Israeli secondary school mathematics teachers. The course provides an introduction to algebraic structures and modern abstract algebra, and links abstract algebra to the high-school curriculum in algebra. It follows the historical attempts of mathematicians to solve polynomial equations of higher degrees, attempts which resulted in the development of group theory and field theory by Galois and Abel. In other words, algebraic structures grew out of a need to solve certain problems, and proved to be a much more fruitful way of viewing them. This theorems in both group theory and field theory. Along the historical ‘journey’, many other major results in algebra in the past 150 years are introduced, and recent directions that current research in algebra is taking are highlighted. This course is part of a unique master’s program – the Rothschild-Weizmann Program – offered by the Weizmann Institute of Science, especially designed for practicing Israeli secondary school teachers. A major component of the program comprises mathematical studies tailored for the students at the program. The rationale and structure of the course Algebra: From Equations to Structures are described, and its relevance to teaching school algebra is examined by analyzing three kinds of data sources. The first are position papers written by the participating teachers regarding the relevance of advanced mathematics studies to expertise in classroom instruction. The second data source are didactic materials designed by the participating teachers in which they connected the mathematics learned in the mathematics courses to the school curriculum and teaching. The third date source are final projects carried out by the teachers based on material learned in the course.Keywords: abstract algebra , linking abstract algebra and school mathematics, school algebra, secondary school mathematics, teacher professional development
Procedia PDF Downloads 14916139 Participation in IAEA Proficiency Test to Analyse Cobalt, Strontium and Caesium in Seawater Using Direct Counting and Radiochemical Techniques
Authors: S. Visetpotjanakit, C. Khrautongkieo
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Radiation monitoring in the environment and foodstuffs is one of the main responsibilities of Office of Atoms for Peace (OAP) as the nuclear regulatory body of Thailand. The main goal of the OAP is to assure the safety of the Thai people and environment from any radiological incidents. Various radioanalytical methods have been developed to monitor radiation and radionuclides in the environmental and foodstuff samples. To validate our analytical performance, several proficiency test exercises from the International Atomic Energy Agency (IAEA) have been performed. Here, the results of a proficiency test exercise referred to as the Proficiency Test for Tritium, Cobalt, Strontium and Caesium Isotopes in Seawater 2017 (IAEA-RML-2017-01) are presented. All radionuclides excepting ³H were analysed using various radioanalytical methods, i.e. direct gamma-ray counting for determining ⁶⁰Co, ¹³⁴Cs and ¹³⁷Cs and developed radiochemical techniques for analysing ¹³⁴Cs, ¹³⁷Cs using AMP pre-concentration technique and 90Sr using di-(2-ethylhexyl) phosphoric acid (HDEHP) liquid extraction technique. The analysis results were submitted to IAEA. All results passed IAEA criteria, i.e. accuracy, precision and trueness and obtained ‘Accepted’ statuses. These confirm the data quality from the OAP environmental radiation laboratory to monitor radiation in the environment.Keywords: international atomic energy agency, proficiency test, radiation monitoring, seawater
Procedia PDF Downloads 17716138 Chemical Composition, Petrology and P-T Conditions of Ti-Mg-Biotites within Syenitic Rocks from the Lar Igneous Suite, East of Iran
Authors: Sasan Ghafaribijar, Javad Hakimi, Mohsen Arvin, Peyman Tahernezhad
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The Lar Igneous Suite (LIS), east of Iran, is part of post collisional alkaline magmatism related to Late Cretaceous- mid Eocene Sistan suture zone. The suite consists of a wide variety of igneous rocks, from volcanic to intrusive and hypabissal rocks such as tuffs, trachyte, monzonite, syenites and lamprophyres. Syenitic rocks which mainly occur in a giant ring dike and stocks, are shoshonitic to potassic-ultrapotassic (K2O/Na2O > 2 wt.%; MgO > 3 wt.%; K2O > 3 wt.%) in composition and are also associated with Cu-Mo mineralization. In this study, chemical composition of biotites within the Lar syenites (LS) is determined by electron microprobe analysis. The results show that LS biotites are Ti-Mg-biotites (phlogopite) which contain relatively high Ti and Mg, and low Fe concentrations. The Mg/(Fe2++ Mg) ratio in these biotites range between 0.56 and 0.73 that represent their transitionally chemical evolution. TiO2 content in these biotites is high and in the range of 3.0-5.4 wt.%. These chemical characteristics indicate that the LS biotites are primary and have been crystallized directly from magma. The investigations also demonstrate that the LS biotites have crystallized from a magma of orogenic nature. Temperature and pressure are the most significant factors controlling Mg and Ti content in the LS biotites, respectively. The results show that the LS biotites crystallized at temperatures (T) between 800 to 842 °C and pressures (P) between 0.99 to 1.44 kbar. These conditions are indicative of a crystallization depth of 3.26-4.74 km.Keywords: sistan suture zone, Lar Igneous Suite, zahedan, syenite, biotite
Procedia PDF Downloads 13916137 Reducing Greenhouse Gass Emissions by Recyclable Material Bank Project of Universities in Central Region of Thailand
Authors: Ronbanchob Apiratikul
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This research studied recycled waste by the Recyclable Material Bank Project of 4 universities in the central region of Thailand for the evaluation of reducing greenhouse gas emissions compared with landfilling activity during July 2012 to June 2013. The results showed that the projects collected total amount of recyclable wastes of about 911,984.80 kilograms. Office paper had the largest amount among these recycled wastes (50.68% of total recycled waste). Groups of recycled waste can be prioritized from high to low according to their amount as paper, plastic, glass, mixed recyclables, and metal, respectively. The project reduced greenhouse gas emissions equivalent to about 2814.969 metric tons of carbon dioxide. The most significant recycled waste that affects the reduction of greenhouse gas emissions is office paper which is 70.16% of total reduced greenhouse gasses emission. According to amount of reduced greenhouse gasses emission, groups of recycled waste can be prioritized from high to low significances as paper, plastic, metals, mixed recyclables, and glass, respectively.Keywords: recycling, garbage bank, waste management, recyclable wastes, greenhouse gases
Procedia PDF Downloads 42916136 Patient Safety Culture in Brazilian Hospitals from Nurse's Team Perspective
Authors: Carmen Silvia Gabriel, Dsniele Bernardi da Costa, Andrea Bernardes, Sabrina Elias Mikael, Daniele da Silva Ramos
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The goal of this quantitative study is to investigate patient safety culture from the perspective of professional from the hospital nursing team.It was conducted in two Brazilian hospitals,.The sample included 282 nurses Data collection occurred in 2013, through the questionnaire Hospital Survey on Patient Safety Culture.Based on the assessment of the dimensions is stressed that, in the dimension teamwork across hospital units, 69.4% of professionals agree that when a lot of work needs to be done quickly, they work together as a team; about the dimension supervisor/ manager expectations and actions promoting safety, 70.2% agree that their supervisor overlooks patient safety problems.Related to organizational learning and continuous improvement, 56.5% agree that there is evaluation of the effectiveness of the changes after its implementation.On hospital management support for patient safety, 52.8% refer that the actions of hospital management show that patient safety is a top priority.On the overall perception of patient safety, 57.2% disagree that patient safety is never compromised due to higher amount of work to be completed.In what refers to feedback and communication about error, 57.7% refer that always and usually receive such information. Relative to communication openness, 42.9% said they never or rarely feel free to question the decisions / actions of their superiors.On frequency of event reporting, 64.7% said often and always notify events with no damages to patients..About teamwork across hospital units is noted similarity between the percentages of agreement and disagreement, as on the item there is a good cooperation among hospital units that need to work together, that indicates 41.4% and 40.5% respectively.Related to adequacy of professionals, 77.8 % disagree on the existence of sufficient amount of employees to do the job, 52.4% agree that shift changes are problematic for patients. On nonpunitive response to errors, 71.7% indicate that when an event is reported it seems that the focus is on the person.On the patient safety grade of the institution, 41.6 % classified it as very good. it is concluded that there are positive points in the safety culture, and some weaknesses as a punitive culture and impaired patient safety due to work overload .Keywords: quality of health care, health services evaluation, safety culture, patient safety, nursing team
Procedia PDF Downloads 30316135 Fe Modified Tin Oxide Thin Film Based Matrix for Reagentless Uric Acid Biosensing
Authors: Kashima Arora, Monika Tomar, Vinay Gupta
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Biosensors have found potential applications ranging from environmental testing and biowarfare agent detection to clinical testing, health care, and cell analysis. This is driven in part by the desire to decrease the cost of health care and to obtain precise information more quickly about the health status of patient by the development of various biosensors, which has become increasingly prevalent in clinical testing and point of care testing for a wide range of biological elements. Uric acid is an important byproduct in human body and a number of pathological disorders are related to its high concentration in human body. In past few years, rapid growth in the development of new materials and improvements in sensing techniques have led to the evolution of advanced biosensors. In this context, metal oxide thin film based matrices due to their bio compatible nature, strong adsorption ability, high isoelectric point (IEP) and abundance in nature have become the materials of choice for recent technological advances in biotechnology. In the past few years, wide band-gap metal oxide semiconductors including ZnO, SnO₂ and CeO₂ have gained much attention as a matrix for immobilization of various biomolecules. Tin oxide (SnO₂), wide band gap semiconductor (Eg =3.87 eV), despite having multifunctional properties for broad range of applications including transparent electronics, gas sensors, acoustic devices, UV photodetectors, etc., it has not been explored much for biosensing purpose. To realize a high performance miniaturized biomolecular electronic device, rf sputtering technique is considered to be the most promising for the reproducible growth of good quality thin films, controlled surface morphology and desired film crystallization with improved electron transfer property. Recently, iron oxide and its composites have been widely used as matrix for biosensing application which exploits the electron communication feature of Fe, for the detection of various analytes using urea, hemoglobin, glucose, phenol, L-lactate, H₂O₂, etc. However, to the authors’ knowledge, no work is being reported on modifying the electronic properties of SnO₂ by implanting with suitable metal (Fe) to induce the redox couple in it and utilizing it for reagentless detection of uric acid. In present study, Fe implanted SnO₂ based matrix has been utilized for reagentless uric acid biosensor. Implantation of Fe into SnO₂ matrix is confirmed by energy-dispersive X-Ray spectroscopy (EDX) analysis. Electrochemical techniques have been used to study the response characteristics of Fe modified SnO₂ matrix before and after uricase immobilization. The developed uric acid biosensor exhibits a high sensitivity to about 0.21 mA/mM and a linear variation in current response over concentration range from 0.05 to 1.0 mM of uric acid besides high shelf life (~20 weeks). The Michaelis-Menten kinetic parameter (Km) is found to be relatively very low (0.23 mM), which indicates high affinity of the fabricated bioelectrode towards uric acid (analyte). Also, the presence of other interferents present in human serum has negligible effect on the performance of biosensor. Hence, obtained results highlight the importance of implanted Fe:SnO₂ thin film as an attractive matrix for realization of reagentless biosensors towards uric acid.Keywords: Fe implanted tin oxide, reagentless uric acid biosensor, rf sputtering, thin film
Procedia PDF Downloads 18616134 Mitigating Nitrous Oxide Production from Nitritation/Denitritation: Treatment of Centrate from Pig Manure Co-Digestion as a Model
Authors: Lai Peng, Cristina Pintucci, Dries Seuntjens, José Carvajal-Arroyo, Siegfried Vlaeminck
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Economic incentives drive the implementation of short-cut nitrogen removal processes such as nitritation/denitritation (Nit/DNit) to manage nitrogen in waste streams devoid of biodegradable organic carbon. However, as any biological nitrogen removal process, the potent greenhouse gas nitrous oxide (N2O) could be emitted from Nit/DNit. Challenges remain in understanding the fundamental mechanisms and development of engineered mitigation strategies for N2O production. To provide answers, this work focuses on manure as a model, the biggest wasted nitrogen mass flow through our economies. A sequencing batch reactor (SBR; 4.5 L) was used treating the centrate (centrifuge supernatant; 2.0 ± 0.11 g N/L of ammonium) from an anaerobic digester processing mainly pig manure, supplemented with a co-substrate. Glycerin was used as external carbon source, a by-product of vegetable oil. Out-selection of nitrite oxidizing bacteria (NOB) was targeted using a combination of low dissolved oxygen (DO) levels (down to 0.5 mg O2/L), high temperature (35ºC) and relatively high free ammonia (FA) (initially 10 mg NH3-N/L). After reaching steady state, the process was able to remove 100% of ammonium with minimum nitrite and nitrate in the effluent, at a reasonably high nitrogen loading rate (0.4 g N/L/d). Substantial N2O emissions (over 15% of the nitrogen loading) were observed at the baseline operational condition, which were even increased under nitrite accumulation and a low organic carbon to nitrogen ratio. Yet, higher DO (~2.2 mg O2/L) lowered aerobic N2O emissions and weakened the dependency of N2O on nitrite concentration, suggesting a shift of N2O production pathway at elevated DO levels. Limiting the greenhouse gas emissions (environmental protection) from such a system could be substantially minimized by increasing the external carbon dosage (a cost factor), but also through the implementation of an intermittent aeration and feeding strategy. Promising steps forward have been presented in this abstract, yet at the conference the insights of ongoing experiments will also be shared.Keywords: mitigation, nitrous oxide, nitritation/denitritation, pig manure
Procedia PDF Downloads 25216133 Gaits Stability Analysis for a Pneumatic Quadruped Robot Using Reinforcement Learning
Authors: Soofiyan Atar, Adil Shaikh, Sahil Rajpurkar, Pragnesh Bhalala, Aniket Desai, Irfan Siddavatam
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Deep reinforcement learning (deep RL) algorithms leverage the symbolic power of complex controllers by automating it by mapping sensory inputs to low-level actions. Deep RL eliminates the complex robot dynamics with minimal engineering. Deep RL provides high-risk involvement by directly implementing it in real-world scenarios and also high sensitivity towards hyperparameters. Tuning of hyperparameters on a pneumatic quadruped robot becomes very expensive through trial-and-error learning. This paper presents an automated learning control for a pneumatic quadruped robot using sample efficient deep Q learning, enabling minimal tuning and very few trials to learn the neural network. Long training hours may degrade the pneumatic cylinder due to jerk actions originated through stochastic weights. We applied this method to the pneumatic quadruped robot, which resulted in a hopping gait. In our process, we eliminated the use of a simulator and acquired a stable gait. This approach evolves so that the resultant gait matures more sturdy towards any stochastic changes in the environment. We further show that our algorithm performed very well as compared to programmed gait using robot dynamics.Keywords: model-based reinforcement learning, gait stability, supervised learning, pneumatic quadruped
Procedia PDF Downloads 31916132 Research of the Rotation Magnetic Field Current Driven Effect on Pulsed Plasmoid Acceleration of Electric Propulsion
Authors: X. F. Sun, X. D. Wen, L. J. Liu, C. C. Wu, Y. H. Jia
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The field reversed closed magnetic field configuration plasmoid has a potential for large thrust and high power propulsion missions such as deep space exploration due to its high plasma density and larger azimuthal current, which will be a most competitive program for the next generation electric propulsion technology. Moreover, without the electrodes, it also has a long lifetime. Thus, the research on this electric propulsion technology is quite necessary. The plasmoid will be formatted and accelerated by applying a rotation magnetic field (RMF) method. And, the essence of this technology lies on the generation of the azimuthal electron currents driven by RMF. Therefore, the effect of RMF current on the plasmoid acceleration efficiency is a concerned problem. In the paper, the influences of the penetration process of RMF in plasma, the relations of frequency and amplitude of input RF power with current strength and the RMF antenna configuration on the plasmoid acceleration efficiency will be given by a two-fluid numerical simulation method. The results show that the radio-frequency and input power have remarkable influence on the formation and acceleration of plasmoid. These results will provide useful advice for the development, and optimized designing of field reversed configuration plasmoid thruster.Keywords: rotation magnetic field, current driven, plasma penetration, electric propulsion
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