Search results for: oxygen evolution reaction
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 5486

Search results for: oxygen evolution reaction

1586 Effects of Kolavironon Liver Oxidative Stress and Beta-Cell Damage in Streptozotocin-Induced Diabetic Rats

Authors: Omolola R. Ayepola, Nicole L. Brooks, Oluwafemi O. Oguntibeju

Abstract:

The liver plays an important role in the regulation of blood glucose and is a target organ of hyperglycaemia. Hyperglycemia plays a crucial role in the onset of various liver diseases and may culminate into hepatopathy if untreated. Alteration in antioxidant defense and increase in oxidative stress that results in tissue injury is characteristic of diabetes. We evaluated the protective effects of kolaviron-a biflavonoid complex, on hepatic antioxidants, lipid peroxidation and apoptosis in the liver of diabetic rats. To induce type I diabetes, rats were injected with streptozotocin intraperitoneally at a single dose of 50 mg/kg. Oral treatment of diabetic rats with kolaviron (100 mg/kg) started on the 6th day after diabetes induction and continued for 6 weeks (5 times weekly). Diabetic rats exhibited a significant increase in the peroxidation of hepatic lipids as observed from the elevated level of malondialdehyde (MDA) estimated by High-Performance Liquid Chromatography. In addition, Oxygen Radical Absorbance Capacity (ORAC), ratio of reduced to oxidized glutathione (GSH/GSSG) and catalase (CAT) activity was decreased in the liver of diabetic rats. TUNEL assay revealed increased apoptotic cell death in the liver of diabetic rats. Examination of Pancreatic beta-cells by immunohistochemical methods revealed beta cell degeneration and reduction in beta cell/ islet area in the diabetic controls. Kolaviron-treatment increased the area of insulin immunoreactive beta-cells significantly. Kolaviron attenuated lipid peroxidation and apoptosis in the liver of diabetic rats, increased CAT activity GSH levels and the resultant GSH: GSSG. The ORAC of kolaviron-treated diabetic liver was restored to near-normal values. Kolaviron protects the liver against oxidative and apoptotic damage induced by hyperglycemia. The antidiabetic effect of kolaviron may also be related to its beneficial effects on beta-cell function.

Keywords: diabetes mellitus, kolaviron, oxidative stress, liver, apoptosis

Procedia PDF Downloads 388
1585 Performance Evaluation of Routing Protocol in Cognitive Radio with Multi Technological Environment

Authors: M. Yosra, A. Mohamed, T. Sami

Abstract:

Over the past few years, mobile communication technologies have seen significant evolution. This fact promoted the implementation of many systems in a multi-technological setting. From one system to another, the Quality of Service (QoS) provided to mobile consumers gets better. The growing number of normalized standards extends the available services for each consumer, moreover, most of the available radio frequencies have already been allocated, such as 3G, Wifi, Wimax, and LTE. A study by the Federal Communications Commission (FCC) found that certain frequency bands are partially occupied in particular locations and times. So, the idea of Cognitive Radio (CR) is to share the spectrum between a primary user (PU) and a secondary user (SU). The main objective of this spectrum management is to achieve a maximum rate of exploitation of the radio spectrum. In general, the CR can greatly improve the quality of service (QoS) and improve the reliability of the link. The problem will reside in the possibility of proposing a technique to improve the reliability of the wireless link by using the CR with some routing protocols. However, users declared that the links were unreliable and that it was an incompatibility with QoS. In our case, we choose the QoS parameter "bandwidth" to perform a supervised classification. In this paper, we propose a comparative study between some routing protocols, taking into account the variation of different technologies on the existing spectral bandwidth like 3G, WIFI, WIMAX, and LTE. Due to the simulation results, we observe that LTE has significantly higher availability bandwidth compared with other technologies. The performance of the OLSR protocol is better than other on-demand routing protocols (DSR, AODV and DSDV), in LTE technology because of the proper receiving of packets, less packet drop and the throughput. Numerous simulations of routing protocols have been made using simulators such as NS3.

Keywords: cognitive radio, multi technology, network simulator (NS3), routing protocol

Procedia PDF Downloads 63
1584 Structural Health Monitoring Method Using Stresses Occurring on Bridge Bearings Under Temperature

Authors: T. Nishido, S. Fukumoto

Abstract:

The functions of movable bearings decline due to corrosion and sediments. As the result, they cannot move or rotate according to the behaviors of girders. Because of the constraints, the bending moments are generated by the horizontal reaction forces and the heights of girders. Under these conditions, the authors obtained the following results by analysis and experiment. Tensile stresses due to the moments occurred at temperature fluctuations. The large tensile stresses on concrete slabs around the bearings caused cracks. Even if concrete slabs are newly replaced, cracks will come out again with function declined bearings. The functional declines of bearings are generally found by using displacement gauges. However the method is not suitable for long-term measurements. We focused on the change in the strains at the bearings and the lower flanges near them at temperature fluctuations. It was found that their strains were particularly large when the movements of the bearings were constrained. Therefore, we developed a long-term health monitoring wireless system with FBG (Fiber Bragg Grating) sensors which were attached to bearings and lower flanges. The FBG sensors have the characteristics such as non-electrical influence, resistance to weather, and high strain sensitivity. Such characteristics are suitable for long-term measurements. The monitoring system was inexpensive because it was limited to the purpose of measuring strains and temperature. Engineers can monitor the behaviors of bearings in real time with the wireless system. If an office is away from bridge sites, the system will save traveling time and cost.

Keywords: bridge bearing, concrete slab,  FBG sensor, health monitoring

Procedia PDF Downloads 222
1583 Human and Environment Coevolution: The Chalcolithic Tell Settlements from Muntenia and Dobrogea, South-Eastern Romania

Authors: Constantin Haita

Abstract:

The chalcolithic tell settlements from south-eastern Romania, attributed to Gumelnița culture, are characterised by a well-defined surface, marked often by delimitation structures, a succession of many layers of construction, destruction, and rebuilding, and a well-structured area of occupation: built spaces, passage areas, waste zones. Settlements of tell type are located in the river valleys –on erosion remnants, alluvial bars or small islands, at the border of the valleys– on edges or prominences of Pleistocene terraces, lower Holocene terraces, and banks of lakes. This study integrates data on the geographical position, the morphological background, and the general stratigraphy of these important settlements. The correlation of the spatial distribution with the geomorphological units of each area of evolution creates an image of the natural landscape in which they occurred. The sedimentological researches achieved in the floodplain area of Balta Ialomiței showed important changes in the alluvial activity of Danube, after the Chalcolithic period (ca. 6500 - 6000 BP), to Iron Age and Middle Ages. The micromorphological analysis, consisting in thin section interpretation, at the microscopic scale, of sediments and soils in an undisturbed state, allowed the interpretation of the identified sedimentary facies, in terms of mode of formation and anthropic activities. Our studied cases reflect some distinct situations, correlating either with the geomorphological background or with the vertical development, the presence of delimiting structures and the internal organization. The characteristics of tells from this area bring significant information about the human habitation of Lower Danube in Prehistory.

Keywords: chalcolithic, micromorphology, Romania, sedimentology, tell settlements

Procedia PDF Downloads 149
1582 Effect of Sulphur Concentration on Microbial Population and Performance of a Methane Biofilter

Authors: Sonya Barzgar, J. Patrick, A. Hettiaratchi

Abstract:

Methane (CH4) is reputed as the second largest contributor to greenhouse effect with a global warming potential (GWP) of 34 related to carbon dioxide (CO2) over the 100-year horizon, so there is a growing interest in reducing the emissions of this gas. Methane biofiltration (MBF) is a cost effective technology for reducing low volume point source emissions of methane. In this technique, microbial oxidation of methane is carried out by methane-oxidizing bacteria (methanotrophs) which use methane as carbon and energy source. MBF uses a granular medium, such as soil or compost, to support the growth of methanotrophic bacteria responsible for converting methane to carbon dioxide (CO₂) and water (H₂O). Even though the biofiltration technique has been shown to be an efficient, practical and viable technology, the design and operational parameters, as well as the relevant microbial processes have not been investigated in depth. In particular, limited research has been done on the effects of sulphur on methane bio-oxidation. Since bacteria require a variety of nutrients for growth, to improve the performance of methane biofiltration, it is important to establish the input quantities of nutrients to be provided to the biofilter to ensure that nutrients are available to sustain the process. The study described in this paper was conducted with the aim of determining the influence of sulphur on methane elimination in a biofilter. In this study, a set of experimental measurements has been carried out to explore how the conversion of elemental sulphur could affect methane oxidation in terms of methanotrophs growth and system pH. Batch experiments with different concentrations of sulphur were performed while keeping the other parameters i.e. moisture content, methane concentration, oxygen level and also compost at their optimum level. The study revealed the tolerable limit of sulphur without any interference to the methane oxidation as well as the particular sulphur concentration leading to the greatest methane elimination capacity. Due to the sulphur oxidation, pH varies in a transient way which affects the microbial growth behavior. All methanotrophs are incapable of growth at pH values below 5.0 and thus apparently are unable to oxidize methane. Herein, the certain pH for the optimal growth of methanotrophic bacteria is obtained. Finally, monitoring methane concentration over time in the presence of sulphur is also presented for laboratory scale biofilters.

Keywords: global warming, methane biofiltration (MBF), methane oxidation, methanotrophs, pH, sulphur

Procedia PDF Downloads 238
1581 Generation of Charged Nanoparticles and Their Contribution to the Thin Film and Nanowire Growth during Chemical Vapour Deposition

Authors: Seung-Min Yang, Seong-Han Park, Sang-Hoon Lee, Seung-Wan Yoo, Chan-Soo Kim, Nong-Moon Hwang

Abstract:

The theory of charged nanoparticles suggested that in many Chemical Vapour Depositions (CVD) processes, Charged Nanoparticles (CNPs) are generated in the gas-phase and become a building block of thin films and nanowires. Recently, the nanoparticle-based crystallization has become a big issue since the growth of nanorods or crystals by the building block of nanoparticles was directly observed by transmission electron microscopy observations in the liquid cell. In an effort to confirm charged gas-phase nuclei, that might be generated under conventional processing conditions of thin films and nanowires during CVD, we performed an in-situ measurement using differential mobility analyser and particle beam mass spectrometer. The size distribution and number density of CNPs were affected by process parameters such as precursor flow rate and working temperature. It was shown that many films and nanostructures, which have been believed to grow by individual atoms or molecules, actually grow by the building blocks of such charged nuclei. The electrostatic interaction between CNPs and the growing surface induces the self-assembly into films and nanowires. In addition, the charge-enhanced atomic diffusion makes CNPs liquid-like quasi solid. As a result, CNPs tend to land epitaxial on the growing surface, which results in the growth of single crystalline nanowires with a smooth surface.

Keywords: chemical vapour deposition, charged nanoparticle, electrostatic force, nanostructure evolution, differential mobility analyser, particle beam mass spectrometer

Procedia PDF Downloads 453
1580 Detection of Leptospira interrogans in Kidney and Urine of water Buffalo and its Relationship with Histopathological and Serological Findings

Authors: M. R. Haji Hajikolaei, A. A. Nikvand, A. R. Ghadrdan, M. Ghorbanpoor, B. Mohammadian

Abstract:

This study was carried out on water buffalo for detection of Leptospira interrogans in kidney and urine and its relationship with serological findings. Blood, urine and kidney samples were taken immediately after slaughter from 353 water buffalos at Ahvaz abattoir in Khouzestan province, Iran. Sera were initially screened at serum dilution of 1:100 against seven live antigens of Leptospira interrogans: pomona, hardjo, ballum, icterohemorrhagiae, tarasovi, australis and grippotyphosa using the microscopic agglutination test (MAT) and sera with positive results were titrated against reacting antigens in serial twofold dilution from 1:100 to 1:800. The samples of kidney were embedded in paraffin wax and 5µm thick sections were stained routinely with Haematoxylin and Eosin (H&E). Polymerase chain reaction (PCR) examination was done on urine and kidney by using LipL32 gene primers. Antibodies against one or more serovars at dilution >:100 were detected in sera. The most frequent reactor was hardjo (56.2%), followed by pomona (52.3%), australis (9.8%), tarassovi (5.9%), grippotyphosa (4.5%) and icterohaemorrhagiae (3.9%). The L. interrogans were detected in 43 (12.2%) of examined buffaloes, so that 26 (8.2%) of kidney tissues, 14 (4.8%) of urine samples separately and 3 (0.84%) of both kidney and urine samples were positive in PCR. From 153 (43.3%) buffaloes with positive MAT, 24 cases were positive by PCR of kidney and/or urine samples, synchronously. Renal lesions such as interstitial nephritis, acute tubular necrosis (ATN), pyelonephritis, glomerolonephritis, renal fibrosis and hydronephrosis were found in 128 (36.3%) cases. Statistical analysis indicated that there was no significant association between results of MAT, PCR and interstitial nephritis.

Keywords: leptospiral infection, PCR, MAT, histopathology, river buffalo

Procedia PDF Downloads 332
1579 Strategies to Promote Entrepreneurship Among University Students: A Case Study from Al Akhawayn University

Authors: Sara atibi, Azzeddine Atibi, Salim Ahmed, Khadija El Kababi

Abstract:

The emergence of an entrepreneurial culture within academic institutions is increasingly seen as essential for preparing students for contemporary economic challenges. This study examines the effectiveness of educational programs and interventions aimed at promoting entrepreneurial spirit at Al Akhawayn University. The central issue explores the types of programs most efficient in instilling the necessary entrepreneurial skills and attitudes in students. The primary question about the ‘types of educational programs and interventions that are most effective in cultivating and reinforcing the entrepreneurial spirit among students at Al Akhawayn University' is broken down into sub-questions detailing the characteristics of current programs, factors influencing their success, the evolution of students' entrepreneurial skills, the role of teachers and mentors, best practices from other institutions, and the long-term impacts on graduates' entrepreneurial careers. To address this question, a mixed-methods approach, combining quantitative and qualitative methods, was adopted. Quantitative data collection includes questionnaires and surveys designed to evaluate students' attitudes, skills, and perceptions before and after participating in entrepreneurship programs. Simultaneously, semi-structured interviews, focus groups, and participant observations provide in-depth qualitative data on the experiences of students, teachers, and administrators. Quantitative data analysis employs descriptive and inferential statistical techniques, while qualitative analysis uses a thematic approach to identify key perceptions and experiences. This triangulation of data ensures robust and comprehensive results.

Keywords: student entrepreneurship, pedagogical interventions, Al Akhawayn university, entrepreneurial culture, entrepreneurial skills

Procedia PDF Downloads 33
1578 The Impact of Social Media on Urban E-planning: A Review of the Literature

Authors: Farnoosh Faal

Abstract:

The rapid growth of social media has brought significant changes to the field of urban e-planning. This study aims to review the existing literature on the impact of social media on urban e-planning processes. The study begins with a discussion of the evolution of social media and its role in urban e-planning. The review covers research on the use of social media for public engagement, citizen participation, stakeholder communication, decision-making, and monitoring and evaluation of urban e-planning initiatives. The findings suggest that social media has the potential to enhance public participation and improve decision-making in urban e-planning processes. Social media platforms such as Facebook, Twitter, and Instagram can provide a platform for citizens to engage with planners and policymakers, express their opinions, and provide feedback on planning proposals. Social media can also facilitate the collection and analysis of data, including real-time data, to inform urban e-planning decision-making. However, the literature also highlights some challenges associated with the use of social media in urban e-planning. These challenges include issues related to the representativeness of social media users, the quality of information obtained from social media, the potential for bias and manipulation of social media content, and the need for effective data management and analysis. The study concludes with recommendations for future research on the use of social media in urban e-planning. The recommendations include the need for further research on the impact of social media on equity and social justice in planning processes, the need for more research on effective strategies for engaging underrepresented groups, and the development of guidelines for the use of social media in urban e-planning processes. Overall, the study suggests that social media has the potential to transform urban e-planning processes but that careful consideration of the opportunities and challenges associated with its use is essential for effective and ethical planning practice.

Keywords: social media, Urban e-planning, public participation, citizen engagement

Procedia PDF Downloads 238
1577 Driver Take-Over Time When Resuming Control from Highly Automated Driving in Truck Platooning Scenarios

Authors: Bo Zhang, Ellen S. Wilschut, Dehlia M. C. Willemsen, Marieke H. Martens

Abstract:

With the rapid development of intelligent transportation systems, automated platooning of trucks is drawing increasing interest for its beneficial effects on safety, energy consumption and traffic flow efficiency. Nevertheless, one major challenge lies in the safe transition of control from the automated system back to the human drivers, especially when they have been inattentive after a long period of highly automated driving. In this study, we investigated driver take-over time after a system initiated request to leave the platooning system Virtual Tow Bar in a non-critical scenario. 22 professional truck drivers participated in the truck driving simulator experiment, and each was instructed to drive under three experimental conditions before the presentation of the take-over request (TOR): driver ready (drivers were instructed to monitor the road constantly), driver not-ready (drivers were provided with a tablet) and eye-shut. The results showed significantly longer take-over time in both driver not-ready and eye-shut conditions compared with the driver ready condition. Further analysis revealed hand movement time as the main factor causing long response time in the driver not-ready condition, while in the eye-shut condition, gaze reaction time also influenced the total take-over time largely. In addition to comparing the means, large individual differences can be found especially in two driver, not attentive conditions. The importance of a personalized driver readiness predictor for a safe transition is concluded.

Keywords: driving simulation, highly automated driving, take-over time, transition of control, truck platooning

Procedia PDF Downloads 253
1576 A Preliminary Study of the Reconstruction of Urban Residential Public Space in the Context of the “Top-down” Construction Model in China: Based on Research of TianZiFang District in Shanghai and Residential Space in Hangzhou

Authors: Wang Qiaowei, Gao Yujiang

Abstract:

With the economic growth and rapid urbanization after the reform and openness, some of China's fast-growing cities have demolished former dwellings and built modern residential quarters. The blind, incomplete reference to western modern cities and the one-off construction lacking feedback mechanism have intensified such phenomenon, causing the citizen gradually expanded their living scale with the popularization of car traffic, and the peer-to-peer lifestyle gradually settled. The construction of large-scale commercial centers has caused obstacles to small business around the residential areas, leading to space for residents' interaction has been compressed. At the same time, the advocated Central Business District (CBD) model even leads to the unsatisfactory reconstruction of many historical blocks such as the Hangzhou Southern Song Dynasty Imperial Street. However, the popularity of historical spaces such as Wuzhen and Hongcun also indicates the collective memory and needs of the street space for Chinese residents. The evolution of Shanghai TianZiFang also proves the importance of the motivation of space participants in space construction in the context of the “top-down” construction model in China. In fact, there are frequent occurrences of “reconstruction”, which may redefine the space, in various residential areas. If these activities can be selectively controlled and encouraged, it will be beneficial to activate the public space as well as the residents’ intercourse, so that the traditional Chinese street space can be reconstructed in the context of modern cities.

Keywords: rapid urbanization, traditional street space, space re-construction, bottom-up design

Procedia PDF Downloads 116
1575 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

Abstract:

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 249
1574 Dialectics of Modern Law: Perspectives and Strategies of Resistance from the Margins

Authors: Nisar Alungal Chungath

Abstract:

“No human being is illegal" has become a dictum strongly upheld in the context of global immigration and migration, highlighting the ethical and moral dimensions of how societies and governments treat individuals and communities who have crossed political borders or are living in a country without legal authorization. It seeks to shift the focus from categorizing human beings as illegal immigrants to recognizing their inherent human rights and the complexities of their circumstances. As a complex social phenomenon, law has been a crucial instrument in shaping, regulating and governing human societies and vice versa. The law has now become a humongous political project of the modern majoritarian regimes to democratically illegitimize and illegalize the unpopular sections and minorities. Drawing from the theoretical frameworks of dialectics, the paper explores the philosophical underpinnings of the historical evolution and dynamic nature of modern law. The paper employs a phenomenological approach to analyze the dialectical relations between individuals, societies, and legal systems, aiming to shed light on the ethical and political implications of these interactions. By examining the historical essence of law, its relationship with social and cultural norms, and the role of power dynamics, this article argues for constantly maintaining the dialectics of law—the dynamic interplay between legal norms, social practices, cultural values, and historical contexts through a philosophical and phenomenological lens, in order to bridge the gap between universal principles and particular contexts. The paper will shed light to the dialectics of the law in the context of instances of the legal persecutions of the modern secular democracies such as Citizenship Amendment Act-2019, India.

Keywords: phenomenology, dialectic, modern law, politics, resistance, margins

Procedia PDF Downloads 56
1573 Vascularized Adipose Tissue Engineering by Using Adipose ECM/Fibroin Hydrogel

Authors: Alisan Kayabolen, Dilek Keskin, Ferit Avcu, Andac Aykan, Fatih Zor, Aysen Tezcaner

Abstract:

Adipose tissue engineering is a promising field for regeneration of soft tissue defects. However, only very thin implants can be used in vivo since vascularization is still a problem for thick implants. Another problem is finding a biocompatible scaffold with good mechanical properties. In this study, the aim is to develop a thick vascularized adipose tissue that will integrate with the host, and perform its in vitro and in vivo characterizations. For this purpose, a hydrogel of decellularized adipose tissue (DAT) and fibroin was produced, and both endothelial cells and adipocytes that were differentiated from adipose derived stem cells were encapsulated in this hydrogel. Mixing DAT with fibroin allowed rapid gel formation by vortexing. It also provided to adjust mechanical strength by changing fibroin to DAT ratio. Based on compression tests, gels of DAT/fibroin ratio with similar mechanical properties to adipose tissue was selected for cell culture experiments. In vitro characterizations showed that DAT is not cytotoxic; on the contrary, it has many natural ECM components which provide biocompatibility and bioactivity. Subcutaneous implantation of hydrogels resulted with no immunogenic reaction or infection. Moreover, localized empty hydrogels gelled successfully around host vessel with required shape. Implantations of cell encapsulated hydrogels and histological analyses are under study. It is expected that endothelial cells inside the hydrogel will form a capillary network and they will bind to the host vessel passing through hydrogel.

Keywords: adipose tissue engineering, decellularization, encapsulation, hydrogel, vascularization

Procedia PDF Downloads 529
1572 Simulation and Controller Tunning in a Photo-Bioreactor Applying by Taguchi Method

Authors: Hosein Ghahremani, MohammadReza Khoshchehre, Pejman Hakemi

Abstract:

This study involves numerical simulations of a vertical plate-type photo-bioreactor to investigate the performance of Microalgae Spirulina and Control and optimization of parameters for the digital controller by Taguchi method that MATLAB software and Qualitek-4 has been made. Since the addition of parameters such as temperature, dissolved carbon dioxide, biomass, and ... Some new physical parameters such as light intensity and physiological conditions like photosynthetic efficiency and light inhibitors are involved in biological processes, control is facing many challenges. Not only facilitate the commercial production photo-bioreactor Microalgae as feed for aquaculture and food supplements are efficient systems but also as a possible platform for the production of active molecules such as antibiotics or innovative anti-tumor agents, carbon dioxide removal and removal of heavy metals from wastewater is used. Digital controller is designed for controlling the light bioreactor until Microalgae growth rate and carbon dioxide concentration inside the bioreactor is investigated. The optimal values of the controller parameters of the S/N and ANOVA analysis software Qualitek-4 obtained With Reaction curve, Cohen-Con and Ziegler-Nichols method were compared. The sum of the squared error obtained for each of the control methods mentioned, the Taguchi method as the best method for controlling the light intensity was selected photo-bioreactor. This method compared to control methods listed the higher stability and a shorter interval to be answered.

Keywords: photo-bioreactor, control and optimization, Light intensity, Taguchi method

Procedia PDF Downloads 395
1571 The Use of Mobile Phone as Enhancement to Mark Multiple Choice Objectives English Grammar and Literature Examination: An Exploratory Case Study of Preliminary National Diploma Students, Abdu Gusau Polytechnic, Talata Mafara, Zamfara State, Nigeria

Authors: T. Abdulkadir

Abstract:

Most often, marking and assessment of multiple choice kinds of examinations have been opined by many as a cumbersome and herculean task to accomplished manually in Nigeria. Usually this may be in obvious nexus to the fact that mass numbers of candidates were known to take the same examination simultaneously. Eventually, marking such a mammoth number of booklets dared and dread even the fastest paid examiners who often undertake the job with the resulting consequences of stress and boredom. This paper explores the evolution, as well as the set aim to envision and transcend marking the Multiple Choice Objectives- type examination into a thing of creative recreation, or perhaps a more relaxing activity via the use of the mobile phone. A more “pragmatic” dimension method was employed to achieve this work, rather than the formal “in-depth research” based approach due to the “novelty” of the mobile-smartphone e-Marking Scheme discovery. Moreover, being an evolutionary scheme, no recent academic work shares a direct same topic concept with the ‘use of cell phone as an e-marking technique’ was found online; thus, the dearth of even miscellaneous citations in this work. Additional future advancements are what steered the anticipatory motive of this paper which laid the fundamental proposition. However, the paper introduces for the first time the concept of mobile-smart phone e-marking, the steps to achieve it, as well as the merits and demerits of the technique all spelt out in the subsequent pages.

Keywords: cell phone, e-marking scheme (eMS), mobile phone, mobile-smart phone, multiple choice objectives (MCO), smartphone

Procedia PDF Downloads 263
1570 Culturable Diversity of Halophilic Bacteria in Chott Tinsilt, Algeria

Authors: Nesrine Lenchi, Salima Kebbouche-Gana, Laddada Belaid, Mohamed Lamine Khelfaoui, Mohamed Lamine Gana

Abstract:

Saline lakes are extreme hypersaline environments that are considered five to ten times saltier than seawater (150 – 300 g L-1 salt concentration). Hypersaline regions differ from each other in terms of salt concentration, chemical composition and geographical location, which determine the nature of inhabitant microorganisms. In order to explore the diversity of moderate and extreme halophiles Bacteria in Chott Tinsilt (East of Algeria), an isolation program was performed. In the first time, water samples were collected from the saltern during pre-salt harvesting phase. Salinity, pH and temperature of the sampling site were determined in situ. Chemical analysis of water sample indicated that Na +and Cl- were the most abundant ions. Isolates were obtained by plating out the samples in complex and synthetic media. In this study, seven halophiles cultures of Bacteria were isolated. Isolates were studied for Gram’s reaction, cell morphology and pigmentation. Enzymatic assays (oxidase, catalase, nitrate reductase and urease), and optimization of growth conditions were done. The results indicated that the salinity optima varied from 50 to 250 g L-1, whereas the optimum of temperature range from 25°C to 35°C. Molecular identification of the isolates was performed by sequencing the 16S rRNA gene. The results showed that these cultured isolates included members belonging to the Halomonas, Staphylococcus, Salinivibrio, Idiomarina, Halobacillus Thalassobacillus and Planococcus genera and what may represent a new bacterial genus.

Keywords: bacteria, Chott, halophilic, 16S rRNA

Procedia PDF Downloads 285
1569 Optimization of Tundish Geometry for Minimizing Dead Volume Using OpenFOAM

Authors: Prateek Singh, Dilshad Ahmad

Abstract:

Growing demand for high-quality steel products has inspired researchers to investigate the unit operations involved in the manufacturing of these products (slabs, rods, sheets, etc.). One such operation is tundish operation, in which a vessel (tundish) acts as a buffer of molten steel for the solidification operation in mold. It is observed that tundish also plays a crucial role in the quality and cleanliness of the steel produced, besides merely acting as a reservoir for the mold. It facilitates removal of dissolved oxygen (inclusions) from the molten steel thus improving its cleanliness. Inclusion removal can be enhanced by increasing the residence time of molten steel in the tundish by incorporation of flow modifiers like dams, weirs, turbo-pad, etc. These flow modifiers also help in reducing the dead or short circuit zones within the tundish which is significant for maintaining thermal and chemical homogeneity of molten steel. Thus, it becomes important to analyze the flow of molten steel in the tundish for different configuration of flow modifiers. In the present work, effect of varying positions and heights/depths of dam and weir on the dead volume in tundish is studied. Steady state thermal and flow profiles of molten steel within the tundish are obtained using OpenFOAM. Subsequently, Residence Time Distribution analysis is performed to obtain the percentage of dead volume in the tundish. Design of Experiment method is then used to configure different tundish geometries for varying positions and heights/depths of dam and weir, and dead volume for each tundish design is obtained. A second-degree polynomial with two-term interactions of independent variables to predict the dead volume in the tundish with positions and heights/depths of dam and weir as variables are computed using Multiple Linear Regression model. This polynomial is then used in an optimization framework to obtain the optimal tundish geometry for minimizing dead volume using Sequential Quadratic Programming optimization.

Keywords: design of experiments, multiple linear regression, OpenFOAM, residence time distribution, sequential quadratic programming optimization, steel, tundish

Procedia PDF Downloads 209
1568 Software Architecture Implications on Development Productivity: A Case of Malawi Point of Care Electronic Medical Records

Authors: Emmanuel Mkambankhani, Tiwonge Manda

Abstract:

Software platform architecture includes system components, their relationships, and design, as well as evolution principles. Software architecture and documentation affect a platform's customizability and openness to external innovators, thus affecting developer productivity. Malawi Point of Care (POC) Electronic Medical Records System (EMRS) follows some architectural design standards, but it lacks third-party innovators and is difficult to customize as compared to CommCare and District Health Information System 2 (DHIS2). Improving software architecture and documentation for the Malawi POC will increase productivity and third-party contributions. A conceptual framework based on Generativity and Boundary Resource Model (BRM) was used to compare the three platforms. Interviews, observations, and document analysis were used to collect primary and secondary data. Themes were found by analyzing qualitative and quantitative data, which led to the following results. Configurable, flexible, and cross-platform software platforms and the availability of interfaces (Boundary Resources) that let internal and external developers interact with the platform's core functionality, hence boosting developer productivity. Furthermore, documentation increases developer productivity, while its absence inhibits the use of resources. The study suggests that the architecture and openness of the Malawi POC EMR software platform will be improved by standardizing web application program interfaces (APIs) and making interfaces that can be changed by the user. In addition, increasing the availability of documentation and training will improve the use of boundary resources, thus improving internal and third-party development productivity.

Keywords: health systems, configurable platforms, software architecture, software documentation, software development productivity

Procedia PDF Downloads 88
1567 The Concentration of Selected Cosmogenic and Anthropogenic Radionuclides in the Ground Layer of the Atmosphere (Polar and Mid-Latitudes Regions)

Authors: A. Burakowska, M. Piotrowski, M. Kubicki, H. Trzaskowska, R. Sosnowiec, B. Myslek-Laurikainen

Abstract:

The most important source of atmospheric radioactivity are radionuclides generated as a result of the impact of primary and secondary cosmic radiation, with the nuclei of nitrogen oxygen and carbon in the upper troposphere and lower stratosphere. This creates about thirty radioisotopes of more than twenty elements. For organisms, the four of them are most important: ³H, ⁷Be, ²²Na, ¹⁴C. The natural radionuclides, which are present in Earth crust, also settle on dust and particles of water vapor. By this means, the derivatives of uranium and thorium, and long-life 40K get into the air. ¹³⁷Cs is the most widespread isotope, that is implemented by humans into the environment. To determine the concentration of radionuclides in the atmosphere, high volume air samplers were used, where the aerosol collection took place on a special filter fabric (Petrianov filter tissue FPP-15-1.5). In 2002 the high volume air sampler AZA-1000 was installed at the Polish Polar Observatory of the Polish Academy of Science in Hornsund, Spitsbergen (77°00’N, 15°33’E), designed to operate in all weather conditions of the cold polar region. Since 1991 (with short breaks) the ASS-500 air sampler has been working, which is located in Swider at the Kalinowski Geophysical Observatory of Geophysics Institute of the Polish Academy of Science (52°07’N, 21°15’E). The following results of radionuclides concentrations were obtained from both stations using gamma spectroscopy analysis: ⁷Be, ¹³⁷Cs, ¹³⁴Cs, ²¹⁰Pb, ⁴⁰K. For gamma spectroscopy analysis HPGe (High Purity Germanium) detector were used. These data were compared with each other. The preliminary results gave evidence that radioactivity measured in aerosols is not proportional to the amount of dust for both studied regions. Furthermore, the results indicate annual variability (seasonal fluctuations) as well as a decrease in the average activity of ⁷Be with increasing latitude. The content of ⁷Be in surface air also indicates the relationship with solar activity cycles.

Keywords: aerosols, air filters, atmospheric beryllium, environmental radionuclides, gamma spectroscopy, mid-latitude regions radionuclides, polar regions radionuclides, solar cycles

Procedia PDF Downloads 143
1566 Computer Simulation of Hydrogen Superfluidity through Binary Mixing

Authors: Sea Hoon Lim

Abstract:

A superfluid is a fluid of bosons that flows without resistance. In order to be a superfluid, a substance’s particles must behave like bosons, yet remain mobile enough to be considered a superfluid. Bosons are low-temperature particles that can be in all energy states at the same time. If bosons were to be cooled down, then the particles will all try to be on the lowest energy state, which is called the Bose Einstein condensation. The temperature when bosons start to matter is when the temperature has reached its critical temperature. For example, when Helium reaches its critical temperature of 2.17K, the liquid density drops and becomes a superfluid with zero viscosity. However, most materials will solidify -and thus not remain fluids- at temperatures well above the temperature at which they would otherwise become a superfluid. Only a few substances currently known to man are capable of at once remaining a fluid and manifesting boson statistics. The most well-known of these is helium and its isotopes. Because hydrogen is lighter than helium, and thus expected to manifest Bose statistics at higher temperatures than helium, one might expect hydrogen to also be a superfluid. As of today, however, no one has yet been able to produce a bulk, hydrogen superfluid. The reason why hydrogen did not form a superfluid in the past is its intermolecular interactions. As a result, hydrogen molecules are much more likely to crystallize than their helium counterparts. The key to creating a hydrogen superfluid is therefore finding a way to reduce the effect of the interactions among hydrogen molecules, postponing the solidification to lower temperature. In this work, we attempt via computer simulation to produce bulk superfluid hydrogen through binary mixing. Binary mixture is a technique of mixing two pure substances in order to avoid crystallization and enhance super fluidity. Our mixture here is KALJ H2. We then sample the partition function using this Path Integral Monte Carlo (PIMC), which is well-suited for the equilibrium properties of low-temperature bosons and captures not only the statistics but also the dynamics of Hydrogen. Via this sampling, we will then produce a time evolution of the substance and see if it exhibits superfluid properties.

Keywords: superfluidity, hydrogen, binary mixture, physics

Procedia PDF Downloads 317
1565 Isolation, Purification and Characterisation of Non-Digestible Oligosaccharides Derived from Extracellular Polysaccharide of Antarctic Fungus Thelebolus Sp. IITKGP-BT12

Authors: Abinaya Balasubramanian, Satyabrata Ghosh, Satyahari Dey

Abstract:

Non-Digestible Oligosaccharides(NDOs) are low molecular weight carbohydrates with degree of polymerization (DP) 3-20, that are delivered intact to the large intestine. NDOs are gaining attention as effective prebiotic molecules that facilitate prevention and treatment of several chronic diseases. Recently, NDOs are being obtained by cleaving complex polysaccharides as it results in high yield and also as the former tend to display greater bioactivity. Thelebolus sp. IITKGP BT-12, a recently identified psychrophilic, Ascomycetes fungus has been reported to produce a bioactive extracellular polysaccharide(EPS). The EPS has been proved to possess strong prebiotic activity and anti- proliferative effects. The current study is an attempt to identify and optimise the most suitable method for hydrolysis of the above mentioned novel EPS into NDOs, and further purify and characterise the same. Among physical, chemical and enzymatic methods, enzymatic hydrolysis was identified as the best method and the optimum hydrolysis conditions obtained using response surface methodology were: reaction time of 24h, β-(1,3) endo-glucanase concentration of 0.53U and substrate concentration of 10 mg/ml. The NDOs were purified using gel filtration chromatography and their molecular weights were determined using MALDI-TOF. The major fraction was found to have a DP of 7,8. The monomeric units of the NDOs were confirmed to be glucose using TLC and GCMS-MS analysis. The obtained oligosaccharides proved to be non-digestible when subjected to gastric acidity, salivary and pancreatic amylases and hence could serve as efficient prebiotics.

Keywords: characterisation, enzymatic hydrolysis, non-digestible oligosaccharides, response surface methodology

Procedia PDF Downloads 130
1564 Romantic Theory in Comparative Perspective: Schlegel’s Philosophy of History and the Spanish Question

Authors: Geena Kim

Abstract:

The Romantic movements in Spain and Germany served as turning points in European literary history, advancing cognitive-emotional ideals of the essential unity between literature, life, and the natural world in reaction against the rising tide of mechanization, urban growth, and industrial progress. This paper offers a comparative study of the literary-theoretic underpinnings of the Romantic movements in Spain and Germany, particularly with regard to the reception history of Schlegel’s Romantic philosophy of history. By far one of the better-known figures of the period, Schlegel has traditionally been considered one of the principal theorists of German Romanticism, one of the first to embrace and acknowledge the more radical changes that the movement brought forth. His well-studied contributions to the German Romanticism were certainly significant domestically, but their impact on comparatively less industrialized Spain have been largely neglected, a puzzling oversight in light of Schlegel’s extensive efforts in advocating for the dissemination of Spanish literature under the guise of a kind of pan-European Romanticism. Indeed, Schlegel’s somewhat problematically exoticizing view of Spain as the quintessential embodiment of the spirit of Romanticism was itself enormously influential on the genesis and growth of the Spanish Romantic theory. This was especially significant considering earlier, pre-Romantic tropes of the ‘black legend,’ by which means Spain was demonized with even cruder essentializing, nationalistic language. By comparing Schlegel’s theorizing around Spain with contributions to Romantic theory by Hispanophone writers, this paper sheds light on questions of linguistic identity and national influence from two alas infrequently compared contexts of European Romanticism.

Keywords: schlegel, Spanish romantic theory, German romanticism, romantic philosophy

Procedia PDF Downloads 190
1563 Water-Fluxed Melting and Back-Arc Extension in the Continental Arc: Evidence from I-Type Granites, Adakitic Rocks and High-Nb Basalts at the Western Margin of the Yangtze Block, South China

Authors: B. Huang, W. Wang, J. H. Zhao

Abstract:

The Neoproterozoic western margin of the Yangtze Block in South China preserves distinctive magmatic associations that record variable water contents and tectonic processes in continental arc settings. Systematic field investigation and detailed petrological studies reveal two distinct magmatic episodes: the Yuanmou Complex (811-802 Ma) and Jinping granites (750 Ma). Through thermodynamic modeling and geochemical analysis, this study demonstrates systematic variations in magma generation controlled by crustal water content at different depths. Phase equilibria modeling indicates the Jinping I-type granites formed through low water-fluxed melting at medium pressure (6-9 kbar), whereas contemporaneous adakitic rocks resulted from high water-flux partial melting of thickened lower crust at high pressure (9-12 kbar). High-Nb basalts in the Yuanmou Complex derived from metasomatized mantle wedge during slab rollback, indicating a back-arc extensional environment. The spatial and temporal relationships between these magmatic rocks constrain the evolution of water content and tectonic setting during continental arc development. Integrated geochemical and isotopic data demonstrate the control of water content on magma generation processes. These findings provide new insights into the mechanisms of crustal growth and reworking in continental arc settings.

Keywords: adakitic and high Nb mafic rocks, back-arc extension, continental Arc, water-fluxed melting

Procedia PDF Downloads 7
1562 Meditation Aided with 40 Hz Binaural Beats Enhances the Cognitive Function and Mood State

Authors: Rubina Shakya, Srijana Dangol, Dil Islam Mansur

Abstract:

The exposure of constant stress stimuli in our daily lives is causing deterioration of neural connectivity in the brain. Interestingly, the improvement in larger-scale neural communication has been argued to rely on brain rhythms, which might be sensitive to binaural beats of particular frequency bands. The theoretical idea behind neural entrainment is that the rhythmic oscillatory activity within and between different brain regions can enhance cognitive function and mood state. So, we aimed to investigate whether the binaural beats of 40 Hz could enhance the cognition and the mood stability of the medical students at Kathmandu University of age 18-25 years old, which possibly, in the long run, might help to enhance their work productivity. The participants were asked to focus on the auditory stimuli of binaural beats with 200 Hz on the right side and 240 Hz on the left side of the headset for 15 minutes, every alternative day of three consecutive weeks. The Stroop’s test and the Brunel Mood Scale (BRUMS) were applied to assess the cognitive function and the mood state, respectively. The binaural beats significantly decreased the reaction time for the incoherent component of Stroop’s test in both male and female participants. For the mood state, scores of all positive emotions except ‘Calmness’ were significantly increased in the case of males. Whereas, scores of all positive emotions except ‘Vigor’ were significantly increased in the case of females. The results suggested that the meditation aided by binaural beats of 40 Hz helps in improving cognition and mood states to some extent.

Keywords: binaural beats, cognitive function, gamma neural oscillation, mood states

Procedia PDF Downloads 141
1561 Understanding the Mechanisms of Salmonella typhimurium Resistance to Cannabidiol

Authors: Iddrisu Ibrahim, Joseph Atia Ayariga, Junhuan Xu, Daniel Abugri, Boakai Robertson, Olufemi S. Ajayi

Abstract:

The emergence of multidrug resistance poses a huge risk to public health globally. Yet these recalcitrant pathogens continue to rise in incidence rate, with resistance rates significantly outpacing the speed of antibiotic development. This, therefore, presents an aura of related health issues such as untreatable nosocomial infections arising from organ transplants and surgeries, as well as community-acquired infections that are related to people with compromised immunity, e.g., diabetic and HIV patients, etc. There is a global effort to fight multidrug-resistant pathogens spearheaded by the World Health Organization, thus calling for research into novel antimicrobial agents to fight multiple drug resistance. Previously, our laboratory demonstrated that Cannabidiol (CBD) was an effective antimicrobial against Salmonella typhimurium (S. typhimurium). However, we observed resistance development over time. To understand the mechanisms S. typhimurium uses to develop resistance to Cannabidiol (CBD), we studied the abundance of bacteria lipopolysaccharide (LPS) and membrane sterols of both susceptible and resistant S. typhimurium. Using real-time quantitative polymerase chain reaction (RT-qPCR), we also analyzed the expression of selected genes known for aiding resistance development in S. typhimurium. We discovered that there was a significantly higher expression of blaTEM, fimA, fimZ, and integrons in the CBD-resistant bacteria, and these were also accompanied by a shift in abundance in cell surface molecules such as lipopolysaccharide (LPS) and sterols.

Keywords: antimicrobials, resistance, cannabidiol, gram-negative bacteria, integrons, blaTEM, Fim, LPS, ergosterols

Procedia PDF Downloads 102
1560 Structural Evolution of Electrodeposited Ni Coating on Ti-6Al-4V Alloy during Heat Treatment

Authors: M. Abdoos, A. Amadeh, M. Adabi

Abstract:

In recent decades, the use of titanium and its alloys due to their high mechanical properties, light weight and their corrosion resistance has increased in military and industry applications. However, the poor surface properties can limit their widely usage. Many researches were carried out to improve their surface properties. The most effective technique is based on solid-state diffusion of elements that can form intermetallic compounds with the substrate. In the present work, inter-diffusion of nickel and titanium and formation of Ni-Ti intermetallic compounds in nickel-coated Ti-6Al-4V alloy have been studied. Initially, nickel was electrodeposited on the alloy using Watts bath at a current density of 20 mA/cm2 for 1 hour. The coated specimens were then heat treated in a tubular furnace under argon atmosphere at different temperatures near Ti β-transus to maximize the diffusion rate for various durations in order to improve the surface properties of the Ti-6Al-4V alloy. The effect of temperature and time on the thickness of diffusion layer and characteristics of intermetallic phases was studied by means of scanning electron microscope (SEM) equipped with energy dispersive X-ray spectrometer (EDS) and microhardness test. The results showed that a multilayer structure was formed after heat treatment: an outer layer of remaining nickel, an area of intermetallic layers with different compositions and solid solution of Ni-Ti. Three intermetallic layers was detected by EDS analysis, namely an outer layer with about 75 at.% Ni (Ni3Ti), an intermediate layer with 50 at.% Ni (NiTi) and finally an inner layer with 36 at.% Ni (NiTi2). It was also observed that the increase in time or temperature led to the formation of thicker intermetallic layers. Meanwhile, the microhardness of heat treated samples increased with formation of Ni-Ti intermetallics; however, its value depended on heat treatment parameters.

Keywords: heat treatment, microhardness, Ni coating, Ti-6Al-4V

Procedia PDF Downloads 435
1559 Hydrogen Production Through Thermocatalytic Decomposition of Methane Over Biochar

Authors: Seyed Mohamad Rasool Mirkarimi, David Chiaramonti, Samir Bensaid

Abstract:

Catalytic methane decomposition (CMD, reaction 4) is a one-step process for hydrogen production where carbon in the methane molecule is sequestered in the form of stable and higher-value carbon materials. Metallic catalysts and carbon-based catalysts are two major types of catalysts utilized for the CDM process. Although carbon-based catalysts have lower activity compared to metallic ones, they are less expensive and offer high thermal stability and strong resistance to chemical impurities such as sulfur. Also, it would require less costly separation methods as some of the carbon-based catalysts may not have an active metal component in them. Since the regeneration of metallic catalysts requires burning of the C on their surfaces, which emits CO/CO2, in some cases, using carbon-based catalysts would be recommended because regeneration can be completely avoided, and the catalyst can be directly used in other processes. This work focuses on the effect of biochar as a carbon-based catalyst for the conversion of methane into hydrogen and carbon. Biochar produced from the pyrolysis of poplar wood and activated biochar are used as catalysts for this process. In order to observe the impact of carbon-based catalysts on methane conversion, methane cracking in the absence and presence of catalysts for a gas stream with different levels of methane concentration should be performed. The results of these experiments prove conversion of methane in the absence of catalysts at 900 °C is negligible, whereas in the presence of biochar and activated biochar, significant growth has been observed. Comparing the results of the tests related to using char and activated char shows the enhancement obtained in BET surface area of the catalyst through activation leads to more than 10 vol.% methane conversion.

Keywords: hydrogen production, catalytic methane decomposition, biochar, activated biochar, carbon-based catalyts

Procedia PDF Downloads 82
1558 Autophagy Defects That Modify Human Immune Cell Metabolism and Promote Aging-Associated Inflammation

Authors: Grace McCambridge, Alanna Keady, Madhur Agrawal, Dequina Nicholas Alvarado, Barbara Nikolajczyk, Leena Panneerseelan-Bharath

Abstract:

Age is a non-modifiable risk factor for the inflammation that underlies pathologies such as type 2 diabetes mellitus (T2DM). Inflammation, as indicated by circulating cytokines, rises in aging, but mechanisms that promote this ‘inflammaging’ remain poorly defined. Furthermore, downstream consequences of inflammaging, including the development of an inflammatory profile that predicts comorbidities like T2DM, remain speculative. We tested the possibility that natural aging-associated changes in autophagy, a process that is compromised in both aging and T2DM, regulates inflammatory profiles in older subjects. Our data showed that circulating CD4⁺ T cells from older compared to younger subjects have (i) defects in autophagy; (ii) higher mitochondria accumulation; (iii) a failure to metabolically shift from oxidative phosphorylation to anaerobic glycolysis upon αCD3/CD28 activation; (iv) more reactive oxygen species (ROS) accumulation; and (v) a cytokine profile that recapitulates the Th17 profile that predicts T2DM. ROS scavenging in cells from older subjects restored mitochondrial mass and membrane potential (indicators of improved autophagy) and reduced Th17 cytokines to amounts made by T cells from younger subjects. Knock-down of the autophagy protein Atg3 in T cells from younger subjects increased mitochondrial accumulation and Th17 cytokines. To begin translating these findings to clinical practice, we showed that physiological concentrations of the diabetes drug metformin (100 µM) added in vitro enhanced autophagy, prevented mitochondria and ROS accumulation, increased anaerobic glycolysis, and decreased Th17 cytokines in activated CD4⁺ T cells from older subjects. Metformin therefore improves autophagy and multiple downstream pro-inflammatory mechanisms CD4⁺ T cells from older subjects. We conclude that autophagy improvement ameliorates the development of a T2DM-predictive Th17 profile in aging, and thus holds promise for delay or prevention of aging-associated metabolic decline.

Keywords: autophagy, mitochondrial turnover, ROS, glycolysis

Procedia PDF Downloads 166
1557 Mitigation of Lithium-ion Battery Thermal Runaway Propagation Through the Use of Phase Change Materials Containing Expanded Graphite

Authors: Jayson Cheyne, David Butler, Iain Bomphray

Abstract:

In recent years, lithium-ion batteries have been used increasingly for electric vehicles and large energy storage systems due to their high-power density and long lifespan. Despite this, thermal runaway remains a significant safety problem because of its uncontrollable and irreversible nature - which can lead to fires and explosions. In large-scale lithium-ion packs and modules, thermal runaway propagation between cells can escalate fire hazards and cause significant damage. Thus, safety measures are required to mitigate thermal runaway propagation. The current research explores composite phase change materials (PCM) containing expanded graphite (EG) for thermal runaway mitigation. PCMs are an area of significant interest for battery thermal management due to their ability to absorb substantial quantities of heat during phase change. Moreover, the introduction of EG can support heat transfer from the cells to the PCM (owing to its high thermal conductivity) and provide shape stability to the PCM during phase change. During the research, a thermal model was established for an array of 16 cylindrical cells to simulate heat dissipation with and without the composite PCM. Two conditions were modeled, including the behavior during charge/discharge cycles (i.e., throughout regular operation) and thermal runaway. Furthermore, parameters including cell spacing, composite PCM thickness, and EG weight percentage (WT%) were varied to establish the optimal material parameters for enabling thermal runaway mitigation and effective thermal management. Although numerical modeling is still ongoing, initial findings suggest that a 3mm PCM containing 15WT% EG can effectively suppress thermal runaway propagation while maintaining shape stability. The next step in the research is to validate the model through controlled experimental tests. Additionally, with the perceived fire safety concerns relating to PCM materials, fire safety tests, including UL-94 and Limiting Oxygen Index (LOI), shall be conducted to explore the flammability risk.

Keywords: battery safety, electric vehicles, phase change materials, thermal management, thermal runaway

Procedia PDF Downloads 145