Search results for: dual solutions

Authors: Hyun Chul Koag, Hyun-Sik Ahn

Abstract:

In this paper, we propose a design approach for the safety mechanism of an actuator used in a commercial vehicle’s EPS system. As the number of electric/electronic system in a vehicle increases, the importance of the functional safety has been receiving much attention. EPS(Electric Power Steering) systems for commercial vehicles require large power than passenger vehicles, and hence, dual motor can be applied to get more torque. We show how to formulate the development process for the design of hardware and software of an EPS system using dual motors. A lot of safety mechanisms for the processor, sensors, and memory have been suggested, however, those for actuators have not been fully researched. It is shown by metric analyses that the target ASIL(Automotive Safety Integrated Level) is satisfied in the point of view of hardware of EPS controller.

Keywords: safety mechanism, functional safety, commercial vehicles, electric power steering

Procedia PDF Downloads 359

Authors: Elena M. Kopteva, Pavlina Jaluvkova, Zdenek Stuchlik

Abstract:

In spite of the numerous attempts to close the discussion about the influence of cosmological expansion on local gravitationally bounded systems, this question arises in literature again and again and remains still far from its final resolution. Here one of the main problems is the problem of obtaining a physically adequate model of strongly gravitating object immersed in non-static cosmological background. Such objects are usually called ‘cosmological’ black holes and are of great interest in wide set of cosmological and astrophysical areas. In this work the set of new exact solutions of the Einstein equations is derived for the flat space that generalizes the known Lemaitre-Tolman-Bondi solution for the case of nonzero pressure. The solutions obtained are pretending to describe the black hole immersed in nonstatic cosmological background and give a possibility to investigate the hot problems concerning the effects of the cosmological expansion in gravitationally bounded systems, the structure formation in the early universe, black hole thermodynamics and other related problems. It is shown that each of the solutions obtained contains either the Reissner-Nordstrom or the Schwarzschild black hole in the central region of the space. It is demonstrated that the approach of the mass function use in solving of the Einstein equations allows clear physical interpretation of the resulting solutions, that is of much benefit to any their concrete application.

Keywords: exact solutions of the Einstein equations, cosmological black holes, generalized Lemaitre-Tolman-Bondi solutions, nonzero pressure

Procedia PDF Downloads 392

Authors: Arash Esmaeili, Zhibang Liu, Yang Xiang, Jimmy Yun, Lei Shao

Abstract:

A high pressure carbon dioxide (CO₂) absorption from a specific gas in a conventional column has been evaluated by the Aspen HYSYS simulator using a wide range of single absorbents and blended solutions to estimate the outlet CO₂ concentration, absorption efficiency and CO₂ loading to choose the most proper solution in terms of CO₂ capture for environmental concerns. The property package (Acid Gas-Chemical Solvent) which is compatible with all applied solutions for the simulation in this study, estimates the properties based on an electrolyte non-random two-liquid (E-NRTL) model for electrolyte thermodynamics and Peng-Robinson equation of state for the vapor and liquid hydrocarbon phases. Among all the investigated single amines as well as blended solutions, piperazine (PZ) and the mixture of piperazine and monoethanolamine (MEA) have been found as the most effective absorbents respectively for CO₂ absorption with high reactivity based on the simulated operational conditions.

Keywords: absorption, amine solutions, Aspen HYSYS, carbon dioxide, simulation

Procedia PDF Downloads 146

Authors: M. F. Haroun, T. A. Gulliver

Abstract:

In this paper, an encryption algorithm is proposed for real-time image encryption. The scheme employs a dual chaotic generator based on a three dimensional (3D) discrete Lorenz attractor. Encryption is achieved using non-autonomous modulation where the data is injected into the dynamics of the master chaotic generator. The second generator is used to permute the dynamics of the master generator using the same approach. Since the data stream can be regarded as a random source, the resulting permutations of the generator dynamics greatly increase the security of the transmitted signal. In addition, a technique is proposed to mitigate the error propagation due to the finite precision arithmetic of digital hardware. In particular, truncation and rounding errors are eliminated by employing an integer representation of the data which can easily be implemented. The simple hardware architecture of the algorithm makes it suitable for secure real-time applications.

Keywords: chaotic systems, image encryption, non-autonomous modulation, FPGA

Procedia PDF Downloads 482

Authors: Turan Çalban, Oral Laçin, Abdüsselam Kurtbaş

Abstract:

The experimental production methods Chevreul’s salt being a intermediate stage product for copper recovery were investigated by dealing with the articles written on this topic. Chevreul’s salt, Cu2SO3.CuSO3.2H2O, being a mixed valence copper sulphite compound has been obtained by using different methods and reagents. Chevreul’s salt has a intense brick-red color. It is a highly stable and expensive salt. The production of Chevreul’s salt plays a key role in hiydrometallurgy. In recent years, researchs on this compound have been intensified. Silva et al. reported that this salt is thermally stable up to 200oC. Çolak et al. precipitated the Chevreul’s salt by using ammonia and sulphur dioxide. Çalban et al. obtained at the optimum conditions by passing SO2 from leach solutions with NH3-(NH4)2SO4. Yeşiryurt and Çalban investigated the optimum precipitation conditions of Chevreul’s salt from synthetic CuSO4 solutions including Na2SO3. Çalban et al. achieved the precipitation of Chevreul’s salt at the optimum conditions by passing SO2 from synthetic CuSO4 solutions. Çalban et al. examined the precipitation conditions of Chevreul’s salt using (NH4)2SO3 from synthetic aqueous CuSO4 solutions. In light of these studies, it can be said that Chevreul’s salt can be produced practically from both a leach solutions including copper and synthetic CuSO4 solutions.

Keywords: Chevreul’s salt, ammonia, copper sulpfite, sodium sülfite, optimum conditions

Procedia PDF Downloads 246

Authors: Hussaini Doko Ibrahim, Hamilton Cyprian Chinwenyi, Henrietta Nkem Ude

Abstract:

In this paper, efforts were made to examine and compare the algorithmic iterative solutions of the conjugate gradient method as against other methods such as Gauss-Seidel and Jacobi approaches for solving systems of linear equations of the form Ax=b, where A is a real n×n symmetric and positive definite matrix. We performed algorithmic iterative steps and obtained analytical solutions of a typical 3×3 symmetric and positive definite matrix using the three methods described in this paper (Gauss-Seidel, Jacobi, and conjugate gradient methods), respectively. From the results obtained, we discovered that the conjugate gradient method converges faster to exact solutions in fewer iterative steps than the two other methods, which took many iterations, much time, and kept tending to the exact solutions.

Keywords: conjugate gradient, linear equations, symmetric and positive definite matrix, gauss-seidel, Jacobi, algorithm

Procedia PDF Downloads 119

Authors: S. Sivakumar, Ashwin Bala, S. Prithviraj, K. Panthala Rajakumaran, R. Pradeep, J. Udhayakumar

Abstract:

Studies reveal that acetylene gas derived from hydrolysis of calcium carbide has similar properties to that of diesel. However, the self-ignition temperature of acetylene gas is higher than that of diesel. Early investigations reveal that acetylene gas could be used as alternative fuel mode. In the present work, acetylene gas of 31/min were inducted and diesel was injected into the combustion chamber of a single cylinder air cooled diesel engine. It was observed that the higher calorific value of acetylene gas improves the brake thermal efficiency at full load conditions. The CO and HC emissions were higher at part load conditions as compared to conventional diesel. The Nox emission level was higher and smoke emission was lower during dual fuel mode under all operating conditions. It is concluded that dual fuel mode of acetylene gas and diesel improves the brake thermal efficiency and reduces smoke in diesel engine.

Keywords: acetylene gas, diesel engine, Nox emission, CO emission, HC emission

Procedia PDF Downloads 341

Authors: Yasuyuki Takahashi, Hirotaka Shimada, Takao Kanzaki

Abstract:

A Dual-detector SPECT system is widely by use of myocardial SPECT studies. With 180-degree (180°) acquisition, reconstructed images are distorted in the posterior wall of myocardium due to the lack of sufficient data of posterior projection. We hypothesized that quality of myocardial SPECT images can be improved by the addition of data acquisition of only a few posterior projections to ordinary 180° acquisition. The proposed acquisition method (180° plus acquisition methods) uses the dual-detector SPECT system with a pair of detector arranged in 90° perpendicular. Sampling angle was 5°, and the acquisition range was 180° from 45° right anterior oblique to 45° left posterior oblique. After the acquisition of 180°, the detector moved to additional acquisition position of reverse side once for 2 projections, twice for 4 projections, or 3 times for 6 projections. Since these acquisition methods cannot be done in the present system, actual data acquisition was done by 360° with a sampling angle of 5°, and projection data corresponding to above acquisition position were extracted for reconstruction. We underwent the phantom studies and a clinical study. SPECT images were compared by profile curve analysis and also quantitatively by contrast ratio. The distortion was improved by 180° plus method. Profile curve analysis showed increased of cardiac cavity. Analysis with contrast ratio revealed that SPECT images of the phantoms and the clinical study were improved from 180° acquisition by the present methods. The difference in the contrast was not clearly recognized between 180° plus 2 projections, 180° plus 4 projections, and 180° plus 6 projections. 180° plus 2 projections method may be feasible for myocardial SPECT because distortion of the image and the contrast were improved.

Keywords: 180° plus acquisition method, a few posterior projections, dual-detector SPECT system, myocardial SPECT

Procedia PDF Downloads 265

Authors: Dragos Ardeleanu, Silviu-Valentin Petre

Abstract:

Written to satisfy the needs of Western powers, classical geopolitics bore the stint of Eurocentrism. Both Mackinder’s heartland and Nicholas Spykman’s rimland were intellectual creations set for the purpose of the Anglophone nations dealing with Eurasia. However, while today’s world is moving towards multipolarity, other emerging regional actors are following their own interests using a different geospatial map. Such is the case of Iran which has developed an engagement pattern in Africa, directed mostly towards costal states, in order to break the rimland grip of Arab states and also the international pressure established against Tehran’s nascent nuclear program. Capitalizing on literature review and analysing statements from key public figures, our paper argues that Iranian African geopolitics displays a dual message: on the one hand, it uses tiers-mondiste rhetoric to garner the support of different coastal African states and, on the other hand, it employs Shiism to gain a foothold in strategic parts of the black continent.

Keywords: African geopolitics, Iran, Shiism, tiers-mondisme

Procedia PDF Downloads 177

Authors: Mehdi Asgarkhani

Abstract:

Today, investment on Information Technology (IT) solutions in most organizations is the largest component of capital expenditure. As capital investment on IT continues to grow, IT managers and strategists are expected to develop and put in practice effective decision making models (frameworks) that improve decision-making processes for the use of IT in organizations and optimize the investment on IT solutions. To be exact, there is an expectation that organizations not only maximize the benefits of adopting IT solutions but also avoid the many pitfalls that are associated with rapid introduction of technological change. Different organizations depending on size, complexity of solutions required and processes used for financial management and budgeting may use different techniques for managing strategic investment on IT solutions. Decision making processes for strategic use of IT within organizations are often referred to as IT Governance (or Corporate IT Governance). This paper examines IT governance - as a tool for best practice in decision making about IT strategies. Discussions in this paper represent phase I of a project which was initiated to investigate trends in strategic decision making on IT strategies. Phase I is concerned mainly with review of literature and a number of case studies, establishing that the practice of IT governance, depending on the complexity of IT solutions, organization's size and organization's stage of maturity, varies significantly – from informal approaches to sophisticated formal frameworks.

Keywords: IT governance, corporate governance, IT governance frameworks, IT governance components, aligning IT with business strategies

Procedia PDF Downloads 379

Authors: Stavros Poulopoulos, Aphrodite Tetorou, Constantine Philippopoulos

Abstract:

Day after day more pharmaceutical compounds that are not efficiently removed by conventional treatment methods are found in treated wastewaters and drinking waters. Due to their refractory nature, they escape conventional wastewater treatment facilities, and thus advanced oxidation processes have to be utilized to effectively eliminate them. In the present study, the removal of Ibuprofen from aqueous solutions containing the commercial drug Algofren (non-steroidal, anti-inflammatory) using UV irradiation, hydrogen peroxide, titanium dioxide and ferric ions was examined. All experiments were conducted in a batch photoreactor operated for 120 min. The main target was to select the most effective operating conditions for the mineralization of the solutions treated. The combination of Fe(III)/ H₂O₂/UV proved to be very efficient in terms of total organic carbon removal and ibuprofen conversion. For solutions containing 5 mg/L ibuprofen and initial total carbon 51.1 mg/L, complete mineralization was achieved by means of 2.2 ppm Fe(III) and 333 mg/L H₂O₂.

Keywords: pharmaceuticals, photocatalytic, photo-Fenton, TiO₂

Procedia PDF Downloads 119

Authors: Flavia Magliacani

Abstract:

The urbanization of the last decades and its resulting urban growth entail problems both for environmental and economic sustainability. From this perspective, sustainable settlement development requires a horizontal decrease in the existing urban structure in order to enhance its greater concentration. Hence, new stratifications of the city fabric and architectural strategies ensuring high-density settlement models are possible solutions. However, although increasing housing density is necessary, it is not sufficient. Guaranteeing the quality of living is, indeed, equally essential. In order to meet this objective, many other factors come to light, namely the relationship between private and public spaces, the proximity to services, the accessibility of public transport, the local lifestyle habits, and the social needs. Therefore, how to safeguard both quality and density in human habitats? The present paper attempts to answer the previous main research question by addressing several sub-questions: Which architectural types meet the dual need for urban density and housing quality? Which project criteria should be taken into consideration by good design practices? What principles are desirable for future planning? The research will analyse different architectural responses adopted in four European cities: Paris, Lion, Rotterdam, and Amsterdam. In particular, it will develop a qualitative and comparative study of two specific architectural solutions which integrate housing density and quality living. On the one hand, the so-called 'self-contained city' model, on the other hand, the French 'Habitat Dense Individualisé' one. The structure of the paper will be as follows: the first part will develop a qualitative evaluation of some case studies, emblematic examples of the two above said architectural models. The second part will focus on the comparison among the chosen case studies. Finally, some conclusions will be drawn. The methodological approach, therefore, combines qualitative and comparative research. Parameters will be defined in order to highlight potential and criticality of each model in light of an interdisciplinary view. In conclusion, the present paper aims at shading light on design approaches which ensure a right balance between density and quality of the urban living in contemporary European cities.

Keywords: density, future design, housing quality, human habitat

Procedia PDF Downloads 80

Authors: Muhammad Danish Khan, Imran Naeem, Mudassar Imran

Abstract:

In this article, we study time-space Fractional Advection-Dispersion (FADE) equation and time-space Fractional Whitham-Broer-Kaup (FWBK) equation that have a significant role in hydrology. We introduce suitable transformations to convert fractional order derivatives to integer order derivatives and as a result these equations transform into Partial Differential Equations (PDEs). Then the Lie symmetries and corresponding optimal systems of the resulting PDEs are derived. The symmetry reductions and exact independent solutions based on optimal system are investigated which constitute the exact solutions of original fractional differential equations.

Keywords: modified Riemann-Liouville fractional derivative, lie-symmetries, optimal system, invariant solutions

Procedia PDF Downloads 405

Authors: Sherine A. El Baradei

Abstract:

Global warming and climatic change are very important topics that are being studied and investigated nowadays as they have lots of diverse impacts on mankind, water quality, aquatic life, wildlife,…etc. Also, many water and hydraulics structures like dams and barrages are being built every day to satisfy water consumption needs, irrigation purposes and power generating purposes. Each of global warming and water structures alone has diversity of impacts on water quality and aquatic life in rivers. This research is investigating the dual combined effect of both water structures and global warming on the water quality and aquatic life through mathematical modeling. A case study of the Esna Barrage on the Nile River in Egypt is being studied. This research study is taking into account the effects of both seasons; namely, winter and summer and their effects on air and hence water temperature of the Nile reach under study. To do so, the study is conducted on the last 23 years to investigate the effect of global warming and climatic change on the studied river water. The mathematical model is then combining the dual effect of the Esna barrage and the global warming on the water quality; as well as, on aquatic life of the Nile reach under study. From the results of the mathematical model, it could be concluded that the dual effect of water structures and global warming is very negative on the water quality and the aquatic life in rivers upstream those structures.

Keywords: aquatic life, barrages, climatic change, dissolved oxygen, global warming, river, water quality, water structures

Procedia PDF Downloads 327

Authors: Rafikoddin Kazi

Abstract:

Almost all the major religions of the world condemn the transactions based on interest which promotes self-centered and materialistic thinking. Still, it is amazing to note that it has become the tradition of transaction at world level hence it is called traditional financial system. The main feature of this system is that it considers economic aspects of the transaction only. This system supports the economic development and not the welfare of humankind. However, it is worth mentioning the fact that, except Islamic financial system no other financial system stood in front of it as a viable alternative system. Although many countries have tried to create financial infrastructure and system, still the Malaysian Islamic financial system has got its own peculiarity. It has made tremendous progress in creating sound Islamic Financial system. However, the historical aspect of this country which has passed through Islamic and traditional financial system has got its own advantages and disadvantages. The advantageous factor is that, despite having mix and heterogeneous culture, it has succeeded in creating Islamic Financial System based on the dual legal system to satisfy the needs of multi-cultural factors. This fact has proved that Islamic Financial System does not need purely Muslim population. However, due to adoption of the dual legal system, several legal issues have been taken place. According to this system, the application of Islamic Law has been limited only up to some family and religious matters. The rest of the matters are being dealt with under the traditional laws, the principles and practices of which are different from that of the Islamic Legal System. The matter becomes all the more complicated when the cases are partially or simultaneously concerned with traditional vis-à-vis Islamic Laws as it requires expertise in both the legal systems. However, the educational principles and systems are different in respect of both the systems. To face this problem, Shariah Advisory Council has been established. But the Multiplicity of Shariah authorities without judicial power has created confusion at various levels. Therefore, some experts have stressed the need for improving, empowering the Islamic financial, legal system to make it more integrated and holistic. In view of the above, an endeavor has been made in this paper to throw some light on the matters related to the adoption of the dual legal system. The paper is conceptual in nature and the method adopted is the intensive survey of literature thereby all the information has been gathered from the secondary sources.

Keywords: Islamic financial system, Islamic legal system, Islamic capital market (ICM) , traditional financial system

Procedia PDF Downloads 167

Authors: Muhammad Sufian Jusoh, Mesliza Mohamed

Abstract:

In this paper, we investigate the existence of positive solutions for a Dirichlet second order boundary value problem by applying the Krasnosel'skii fixed point theorem on compression and expansion of cones.

Keywords: Krasnosel'skii fixed point theorem, positive solutions, Dirichlet boundary value problem, Dirichlet second order boundary problem

Procedia PDF Downloads 387

Authors: Yi-Jung Chen, Yunshi Liu

Abstract:

To explain how followers can perceive whether or not transformational leaders are authentic on the basis of their leadership behaviors based on value-based leadership theory, this study adopts the dual-focus model of transformational leadership and evaluates leaders’ corporate social responsibility values along with followers’ perceptions of leaders’ values. Using dyadic questionnaires, the final study sample consisted of 252 followers and 43 leaders at a private firm in Taiwan. Results show that followers perceive corporate social responsibility values of transformational leaders through their group-focused leadership behaviors because such group-focused leadership is in line with these values.

Keywords: authentic transformational leadership, corporate social responsibility value, value-based leadership theory, dual-focus leadership

Procedia PDF Downloads 280

Authors: Nadia Theuma

Abstract:

Climate change is a reality that has started to leave an impact on the physical environment as well as on the built environment, in particular built heritage. This paper explores the argument that climate change is also a trigger which can lead to identifying a number of creative solutions that can transform built heritage into sustainable buildings. Using the Maltese Islands, and in particular the city of Valletta which is also a World Heritage Site, this paper illustrates some of the innovative solutions that are being developed to make heritage buildings more sustainable and in doing so, mitigating the negative impacts of climate change. The paper looks in detail at the most notable initiatives being developed, their implementation and application, which at times is not easy considering the restrictions within protected built heritage areas and the positive impacts that they will have on visitor experience and overall sustainability of the Maltese tourism product. The paper will conclude by outlining how these solutions can be adapted to buildings with similar climatic conditions.

Keywords: built heritage, creative solutions, climate change, Maltese Islands

Procedia PDF Downloads 262

Authors: So Hyun Ahn, Geu Rim Seo, Byungsoo Shin, Kwang-Won Yu, Hyung Joo Suh, Sung Hee Han

Abstract:

We investigated the effects of GOS, lactulose and DuOligo in loperamide-induced constipation rat model. Dual-Oligo saccharide (DuOligo) was composed with galacto-oligosaccharide (GOS) and lactulose. GOS is an important dietary prebiotics that affects intestinal microbiota and barrier functions to have beneficial effect and lactulose is used as a laxative to treat constipation. To study the DuOligo, after adaptation period of four weeks of Spraque-Dawley rats, loperamide (5 mg/kg, twice per day) was injected to induce constipation for 1 week. DuOligo increased the fecal pellet amount, fecal weight, and water content of feces in rats with loperamide-induced constipation. DuOligo groups tended to produce more total fatty acid than that of observed for the control group. Gastrointestinal transit ratio and length and area of intestinal mucosa increased after treatment with DuOligo in loperamide-induced rats. These results showed that oral administration of DuOligo significantly modulated intestinal peristalsis.

Keywords: constipation, DuOligo, GOS, lactulose

Procedia PDF Downloads 388

Authors: S. Zenhari, M. R. Hematiyan, A. Khosravifard, M. R. Feizi

Abstract:

The boundary element method (BEM) and the method of fundamental solutions (MFS) are well-known fundamental solution-based methods for solving a variety of problems. Both methods are boundary-type techniques and can provide accurate results. In comparison to the finite element method (FEM), which is a domain-type method, the BEM and the MFS need less manual effort to solve a problem. The aim of this study is to compare the accuracy and reliability of the BEM and the MFS. This comparison is made for 2D potential and elasticity problems with different boundary and loading conditions. In the comparisons, both convex and concave domains are considered. Both linear and quadratic elements are employed for boundary element analysis of the examples. The discretization of the problem domain in the BEM, i.e., converting the boundary of the problem into boundary elements, is relatively simple; however, in the MFS, obtaining appropriate locations of collocation and source points needs more attention to obtain reliable solutions. The results obtained from the presented examples show that both methods lead to accurate solutions for convex domains, whereas the BEM is more suitable than the MFS for concave domains.

Keywords: boundary element method, method of fundamental solutions, elasticity, potential problem, convex domain, concave domain

Procedia PDF Downloads 62

Authors: Anneline Chetty

Abstract:

Innovation is not always born in a sterile lab or is not always about applications and technology. Innovative solutions to community challenges can be borne out of the creativity of community members. This was proven by Professor Anil Gupta who for more than two decades scoured rural India for its hidden innovations motivated by the belief that the most powerful ideas for fighting poverty and hardship will not come from corporate research labs, but from ordinary people struggling to survive. The Ethekwini Municipality is a city in South Africa which adopted a similar approach, recognising the innovativeness of youth (students and school pupils) in its area. The intention was to make the youth a part of the solution to challenges faced by the Municipality. In this regard, five areas were selected and five groups of students were identified. Each group was sent into the community to identify challenges and engage with community leaders as well as members. Each group was tasked to come with solutions to these challenges which were to be presented at an Innovation Summit. The presented solutions were judged and the winning solution would be implemented by the Municipality. This paper, documents the experience of the students as well as the kinds of solutions that were presented. The purpose is to highlight the importance of using the ingenious minds and creativity of youth and channel their energy into becoming part of society’s solutions as opposed to being the problem

Keywords: innovation, indigenous, entrepreneurship, community

Procedia PDF Downloads 372

Authors: Nike Jacobs, Elizelle Juanee Cilliers

Abstract:

In recent decades there has been an increasing strive towards broader sustainable planning practices. A wide range of literature suggests that nature-based solutions (including Green Infrastructure planning) may lead towards socio-economically and environmentally sustainable urban communities. Such research is however mainly based on practices from the Global North with very little reference to the Global South. This study argues that there is a need for Global North knowledge to be translated to Global South context, and interpreted within this unique environment, acknowledging historical and cultural differences between Global North and Global South, and ultimately providing unique solutions for the unique urban reality. This research primarily focuses on nature-based solutions for sustainable urban communities and considers a broad literature review on Global North knowledge regarding such, substantiated by an analysis of purposefully selected case studies. The investigation identifies best practices which could be translated and place such in the context of current Global South perspectives.

Keywords: global south, green infrastructure planning, nature-based solutions, sustainable urbanism, urban sustainability

Procedia PDF Downloads 223

Authors: N. Senu, I. A. Kasim, F. Ismail, N. Bachok

Abstract:

In this paper zero-dissipative explicit Runge-Kutta method is derived for solving second-order ordinary differential equations with periodical solutions. The phase-lag and dissipation properties for Runge-Kutta (RK) method are also discussed. The new method has algebraic order three with dissipation of order infinity. The numerical results for the new method are compared with existing method when solving the second-order differential equations with periodic solutions using constant step size.

Keywords: dissipation, oscillatory solutions, phase-lag, Runge-Kutta methods

Procedia PDF Downloads 377

Authors: Immanuel Darkwa

Abstract:

Climate change and environmental degradation are existential threats requiring urgent transnational action. The SDGs, as well as regional initiatives the like European Green Deal, as ambitious as they are, put an emphasis on innovatively tackling threats posed by climate change regionally. While co-creational approaches are being propagated, there is no reference blueprint for how potential solutions, particularly nature-based solutions, may be developed and implemented within urban-settings. Using a single case study in Zagreb, Croatia, this paper proposes a workshop-tool for a Living Lab as a Service model for sustainable Nature-Based-Thinking, Nature–Centred-Design and Nature based solutions. The approach is based on a co-creational methodology developed through literature synthesis, expert interviews, focus group discussions, surveys and synthesized through rigorous research analysis and participatory observation. The ensuing tool involves workshop-processes, tested with through-the-process identified stakeholders with distinctive roles and functions. The resulting framework proposes a Nature-Based-Centred-Thinking process tool involving ‘green’ routines supported by a focal unit and a collaborative network, and that allows for the development of nature-based solutions.

Keywords: living labs, nature-based solutions, nature- based design, innovation processes, innovation routines and tools

Procedia PDF Downloads 39

Authors: Jing Li, Li Jin, Fulin Wang, Jie Dong, Wenjiang Ding

Abstract:

Mg-Li dual-phase alloy exhibits better combination of yield strength and elongation than the Mg single-phase alloy. To exploit its deformation behavior, the deformation mechanisms of Mg-2Gd alloy with or without Li addition, i.e., Mg-6Li-2Gd and Mg-2Gd alloy, have been studied at both microscale and mesoscale. EBSD-assisted slip trace, twin trace, and texture evolution analysis show that the α-Mg phase of Mg-6Li-2Gd alloy exhibits different microscopic deformation mechanisms with the Mg-2Gd alloy, i.e., mainly prismatic slip in the former one, while basal slip, prismatic slip and extension twin in the latter one. Further Schmid factor analysis results attribute this different intra-phase deformation mechanisms to the higher critical resolved shear stress (CRSS) value of extension twin and lower ratio of CRSSprismatic /CRSSbasal in the α-Mg phase of Mg-6Li-2Gd alloy. Additionally, Li addition can induce dual-phase microstructure in the Mg-6Li-2Gd alloy, leading to the formation of hetero-deformation induced (HDI) stress at the mesoscale. This can be evidenced by the hysteresis loops appearing during the loading-unloading-reloading (LUR) tensile tests and the activation of multiple slip activity in the α-Mg phase neighboring β-Li phase. The Mg-6Li-2Gd alloy shows higher yield strength is due to the harder α-Mg phase arising from solid solution hardening of Li addition, as well asthe strengthening of soft β-Li phase by the HDI stress during yield stage. Since the strain hardening rate of Mg-6Li-2Gd alloy is lower than that of Mg-2Gd alloy after ~2% strain, which is partly due to the weak contribution of HDI stress, Mg-6Li-2Gd alloy shows no obvious increase of uniform elongation than the Mg-2Gd alloy.But since the β-Li phase is effective in blunting the crack tips, the Mg-6Li-2Gd alloy shows ununiform elongation, which, thus, leads to the higher total elongation than the Mg-2Gd alloy.

Keywords: Mg-Li-Gd dual-phase alloy, phase boundary, HDI stress, dislocation slip activity, mechanical properties

Procedia PDF Downloads 167

Authors: Zhijun Peng, Xiang Li, Dayou Li, Raouf Mobasheri, Abdel Aitouche

Abstract:

To implement carbon capture and storage (CCS) for eliminating carbon dioxide (CO₂) emissions, this paper describes a study on oxy-fuel combustion (OFC) with an ethanol-gasoline dual-fuel spark ignition (DFSI) engine under economical oxygen consumption at low and mid-high loads which was performed by 1D simulation. It is demonstrated that under OFC mode without other optimisation, brake mean effective pressure (BMEP) can meet the requirement at mid-high load, but it has a considerable decline at low load compared to conventional air combustion (CAC) mode. Moreover, there is a considerable deterioration in brake specific fuel consumption (BSFC) compared to that of CAC mode. A practical method is proposed to optimise the DFSI engine performance under OFC mode by changing intake charge components and utilising appropriate water injection (WI) strategies.

Keywords: oxy-fuel combustion, dual-fuel spark ignition engine, ethanol, gasoline, computer simulation

Procedia PDF Downloads 63

Authors: Ehsan Motamedian

Abstract:

Finding all optimal flux distributions of a metabolic model is an important challenge in systems biology. In this paper, a new algorithm is introduced to identify all alternate optimal solutions of a large scale metabolic network. The algorithm reduces the model to decrease computations for finding optimal solutions. The algorithm was implemented on the Escherichia coli metabolic model to find all optimal solutions for lactate and acetate production. There were more optimal flux distributions when acetate production was optimized. The model was reduced from 1076 to 80 variable fluxes for lactate while it was reduced to 91 variable fluxes for acetate. These 11 more variable fluxes resulted in about three times more optimal flux distributions. Variable fluxes were from 12 various metabolic pathways and most of them belonged to nucleotide salvage and extra cellular transport pathways.

Keywords: flux variability, metabolic network, mixed-integer linear programming, multiple optimal solutions

Procedia PDF Downloads 396

Authors: Maria Bercea, Monica Diana Olteanu

Abstract:

Investigation of polymer systems able to change inside of the body into networks represent an attractive approach, especially when there is a minimally invasive and patient friendly administration. Pharmaceutical formulations based on Pluronic F127 [poly (oxyethylene) (PEO) blocks (70%) and poly(oxypropylene) (PPO) blocks (30%)] present an excellent potential as drug delivery systems. The use of Pluronic F127 alone as gel-forming solution is limited by some characteristics, such as poor mechanical properties, short residence time, high permeability, etc. Investigation of the interactions between the natural and synthetic polymers and surfactants in solution is a subject of great interest from both scientific and practical point of view. As for example, formulations based on Pluronics and chitosan could be used to obtain dual phase transition hydrogels responsive to temperature and pH changes. In this study, different materials were prepared by using poly(vinyl alcohol), chitosan solutions mixed with aqueous solutions of Pluronic F127. The rheological properties of different formulations were investigated in temperature sweep experiments as well as at a constant temperature of 37oC for exploring in-situ gel formation in the human body conditions. In addition, some viscometric investigations were carried out in order to understand the interactions which determine the complex behaviour of these systems. Correlation between the thermodynamic and rheological parameters and phase separation phenomena observed for the investigated systems allowed the dissemination the constitutive response of polymeric materials at different external stimuli, such as temperature and pH. The rheological investigation demonstrated that the viscoelastic moduli of the hydrogels can be tuned depending on concentration of different components as well as pH and temperature conditions and cumulative contributions can be obtained.

Keywords: hydrogel, polymer mixture, stimuli responsive, biomedical applications

Procedia PDF Downloads 323

Authors: Narjes Tahmasbi

Abstract:

Burnout is considered a work-related syndrome made from a person’s recognition of a gap between expecting success in professional performance and less satisfying reality. Teaching, as one of the most stressful jobs in the world, creates a sense of burnout that disturbs the competency of teachers’ personal and professional features, and it can be dangerous for themselves as well as their students. Recently, there has been growing research on the different effects of burnout; however, it is necessary to investigate the causes of this issue, especially in universities. This study aims to investigate the causes and recommended solutions to burnout in the teaching careers of university professors. The participants of the study were 5 EFL university professors from an institution of higher education in Shiraz, Iran. The current study used a qualitative design. Data were obtained from an interview with all participants. The participants were asked to answer 8 questions that were made through a semi-instructional interview. The results of the interview with the participants indicated that there were 4 main reasons that cause burnout in teachers: lack of student motivation, environmental factors, interpersonal problems, and financial problems. Recommended solutions were different according to the different personalities, creativity, and experiences of participants. The discussion of each of the causes of burnout represents how these categories cause burnout, and the discussion of each of the solutions shows how a teacher can handle burnout.

Keywords: burnout, EFL teachers, reasons, solutions, work-related syndrome

Procedia PDF Downloads 50

Authors: Shashank Patidar, Sumit Kumar, Atul Srivastava, Suneet Singh

Abstract:

Present work is concerned with the numerical investigation of thermal response of biological tissues during laser-based photo-thermal therapy for destroying cancerous/abnormal cells with minimal damage to the surrounding normal cells. Light propagation through the biological sample is mathematically modelled by transient radiative transfer equation. In the present work, application of the Lattice Boltzmann Method is extended to analyze transport of short-pulse radiation in a participating medium.In order to determine the two-dimensional temperature distribution inside the tissue medium, the RTE has been coupled with Penne’s bio-heat transfer equation based on Fourier’s law by several researchers in last few years.

Keywords: lattice Boltzmann method, transient radiation transfer equation, dual phase lag model

Procedia PDF Downloads 322