Numerical Modeling of Flame Lift-Off Phenomenon and Calculation of Thermal Loads on a Methane Fuel Injector With Complex Geometry

A numerical study has been conducted to analyze a fuel injector with three in-line cylinder geometry that has been adopted as a model for investigating the combustion phenomenon in the 8-Foot High Temperature Tunnel (HTT) combustor at the NASA Langley Research Center. The primary objective here is to analyze the flame lift-off phenomenon in the three cylinder fuel injector geometry in two-dimensions. The fluid mechanics model used in the analysis includes time-averaged Navier-Stokes equations that are employed in conjunction with a two-equation k-$\epsilon$ model for predicting the effects of turbulence. Calculations were performed with three chemistry models, namely fast chemistry, one-step and two-step reaction kinetics. The coupled elliptic, non-linear, partial differential equations are solved by an existing quadratic upwind scheme. Predictions are made for the flame lift-off, injector surface temperature and thermal load resulting from the combustion phenomenon downstream of the fuel injector. Effects of fuel jet velocity, chemistry model, inlet turbulent intensity and oxygen enrichment on the flame lift-off phenomenon, and the thermal load on the fuel injector are analyzed by considering simultaneously combined convection (outside the cylinders) and conduction (inside the cylinders). Results indicate that as the fuel jet velocity is increased, the flame is transformed from a wrap around configuration to a clearly lifted flame configuration. Of the three chemistry models considered in the present study, only the two-step chemistry model predicts a clearly lifted flame. The results indicate that as the fuel injection velocity is increased the thermal load and peak surface temperature decreases sharply (as the flame gets detached from the injector surface). The effect of oxygen enrichment on the combustion process is very pronounced and causes the establishment of a wrap around flame even at higher injection velocities

The role of Islamic finance in enhancing financial inclusion in organization of Islamic cooperation (OIC) countries

The core principles of Islam lay great emphasis on social justice, inclusion, and sharing of resources between the haves and the have nots. Islamic finance addresses the issue of"financial inclusion"or"access to finance"from two directions -- one through promoting risk-sharing contracts that provide a viable alternative to conventional debt-based financing, and the other through specific instruments of redistribution of the wealth among the society. Use of risk-sharing financing instruments can offer Shariah-compliant microfinance, financing for small and medium enterprises, and micro-insurance to enhance access to finance. And redistributive instruments such as Zakah, Sadaqat, Waqf, and Qard-al-hassan complement risk-sharing instruments to target the poor sector of society to offer a comprehensive approach to eradicating poverty and to build a healthy and vibrant economy. Instruments offered by Islam have strong historical roots and have been applied throughout history in various Muslim communities. The paper identifies gaps currently existing in Organisation of Islamic Cooperation (OIC) countries on each front, that is, Shariah-compliant micro-finance and financing for small and medium enterprises and the state of traditional redistributive instruments. The paper concludes that Islam offers a rich set of instruments and unconventional approaches, which, if implemented in true spirit, can lead to reduced poverty and inequality in Muslim countries plagued by massive poverty. Therefore, policy makers in Muslim countries who are serious about enhancing access to finance or"financial inclusion"should exploit the potential of Islamic instruments to achieve this goal and focus on improving the regulatory and financial infrastructure to promote an enabling environment.Access to Finance,Debt Markets,Banks&Banking Reform,Emerging Markets,Islamic Finance

On financial liberalisation in LDCs : the case of Egypt, 1960-93

This thesis deals with the issue of financial development in Egypt at the sectoral, macroeconomic and household levels over the period 1960-93. The thesis is organised in ten chapters, including a summary of the main results in chapter (10). Chapter (1) provides an introduction of the topics treated in the thesis and an overview of the main developments in the Egyptian economy during the study period. Chapter (2) reviews the theoretical literature and empirical studies on the main issues concerning financial development. Chapters (3) and (4) derive stylised facts from the discussion of the evolution of the financial system in Egypt. Chapter (3) assesses the structure, regulation and performance of the banking sector. Chapter (4) focuses on the Egyptian securities market, exploring its development since its establishment in 1883. Further it analyses the performance of the market using the main published indicators and highlights the impediments to its progress. Chapter (5) is concerned with the growing role of Islamic finance in both the formal and informal sectors in Egypt. After constructing a model to illustrate the distinctive characteristics of Islamic banking, the chapter investigates the role of Islamic banks and Islamic branches of conventional banks. The chapter also provides an analysis of the Informal Islamic Investment Companies which flourished in Egypt during the 1980s. Chapter (6) analyses the causes, measures and impact of financial repression in Egypt over the period 1960-90. The findings of this chapter indicate that financing the budget deficit was the main reason for repressing the financial sector. The chapter discusses the impact of the different repressive methods used including inflation tax, interest rate ceilings, high reserve requirements, directed credit schemes, regulation on the portfolio composition of banks, and government ownership of financial intermediaries. The government revenues from particular repressive measures such as inflation tax, seigniorage and interest rate ceilings were estimated for the whole study period and were substantial by most international standards. There follows a discussion of the main consequences of financial repression including capital flight, money substitution, the excessive use of inflation hedges and the thriving of informal financial transactions. Chapter (7) presents an econometric analysis of the impact of the real interest rate on saving, investment and economic growth in Egypt. The results of this analysis indicate that the real interest rate had a positive impact on financial saving, possibly through a portfolio shift. However its impact on total saving, investment and economic growth was insignificant. Chapters (8) and (9) are concerned with the issue of the coexistence of formal and informal financial sectors in rural Egypt. The analysis is based on a survey, of 200 households undertaken by the author in four Egyptian villages in the Nile delta. The methodology adopted and the description of the surveyed region are reported in chapter (8). The findings provided in chapter (9) suggest that informal financial transactions in our sample can be classified as intermittent. There was no evidence of the existence of professional money lenders. Loans, with very few exceptions, were interest free. Most loans were undertaken without contract or collateral. However default cases were low thanks to societal governance. Moreover the chapter analyses the characteristics of RoSCA in Egypt and its role in financial intermediation. The determinants of formal and informal borrowing are estimated using Tobit analysis. The chapter concludes with a discussion of the implications of financial liberalisation on household credit decisions. This thesis highlights the importance of a liberalised financial system for economic development in Egypt. However it argues that financial liberalisation, on its own, is not a sufficient remedy for the problems encountered in the financial sector. Macroeconomic stability and prudential regulation are considered to be essential prerequisites for liberalisation. In addition the thesis strongly emphasises the need for the restructuring of the financial system and the ensuring of its compatibility with the cultural environment to enable the full realisation of the benefits of financial liberalisation

Digital transformation and localizing the Sustainable Development Goals (SDGs)

© 2019 Elsevier B.V. This paper examines how digital transformation can impact the localization and achievement of the Sustainable Development Goals (SDGs). We collect data on the progress made towards SDGs, existing e-governance and big data initiatives, as well as the state of localization in seven countries from different parts of the world. We find that localization allows governments to effectively tailor sustainable development strategies at the local level, which can be boosted with digital transformation. Localization requires local governments’ effective planning by ensuring that budgetary allocations reflect the priorities of local communities. Our main recommendations are that adequate data are necessary to identify and follow-up with decision makers, which requires a review of institutional competence in dealing with information and data and the use of digital transformation for this purpose. Appropriate funding for development programs and projects and effective application at the local level are also important. This requires policy makers to direct and encourage investments in the ‘The Digital Network Architecture’ (DNA) infrastructure and human capital. A key limitation lies in its sample of countries used with their own cultural and population features. However, our findings provide a good basis to analyse further case studies with more heterogeneous compositions as well as other practices of digital transformation

Los ODS como marco operativo para la respuesta y recuperación post COVID-19

Despite progress on a number of goals, the world was not moving fast enough towards achieving the Sustainable Development Goals in the pre-COVID era. The Decade of Action started with the hit of the COVID-19 crisis, which stressed the urgent need to tackle the root causes of vulnerabilities. This paper explores the roles of different critical actors towards achieving the sustainable development goals (SDGs), namely national governments; local and regional governments and local communities; and the business sector as well as the interactions among these actors that facilitate the implementation of the SDGs. The paper also discusses how the SDGs provide an operational framework for building back better during the response and recovery phases from the crisis and how the COVID-19 pandemic has changed the policy scene to reimagine the roles played by the different actors. Lastly, the paper elaborates on three critical factors that would shape the degree of progress in the next decade, namely dependable data, adequate finance and effective implementation of development policies.A pesar del progreso en una serie de objetivos, el mundo no avanzaba lo suficientemente rápido hacia el logro de los Objetivos de Desarrollo Sostenible en la era anterior a COVID. La Década de Acción comenzó con el impacto de la crisis de COVID-19, que enfatizó la urgente necesidad de abordar las causas profundas de las vulnerabilidades. Este documento explora los roles de diferentes actores críticos hacia el logro de los Objetivos de Desarrollo Sostenible (ODS), a saber, los gobiernos nacionales; gobiernos locales y regionales y comunidades locales; y el sector empresarial, así como las interacciones entre estos actores que facilitan la implementación de los ODS. El documento también analiza cómo los ODS proporcionan un marco operativo para reconstruir mejor durante las fases de respuesta y recuperación de la crisis y cómo la pandemia de COVID-19 ha cambiado el escenario de las políticas para reinventar los roles desempeñados por los diferentes actores. Por último, el documento desarrolla tres factores críticos que darían forma al grado de progreso en la próxima década, a saber, datos confiables, financiamiento adecuado y la implementación efectiva de políticas de desarrollo

Big Data Applications in Digital Marketing

Every year, a set of new trends arise that change the course of the digital marketing process and make it easier for marketers to do their work and save time continuously. One of the most critical new trends that have greatly influenced digital marketing and are expected to sustain its impact in the future is Big Data. This article aimed to outline the role of big data in digital marketing by discussing its various applications in digital marketing operations. This article was based on the systematic review methodology by reviewing the previous literature in the study area. The results obtained from the literature showed various applications of big data analytics in digital marketing, including (improving customer experience, measuring and analyzing competitors, innovation and product development....etc.). The article also discovered that companies regularly employ big data to improve the accuracy of different marketing decisions, such as enhancing customer knowledge, providing highly customized promotional content, increasing sales, and measuring the effectiveness of digital marketing campaigns. This article will provide a theoretical base for future researchers to conduct a field study on Turkish companies to examine to what extent they are using big data analytics in digital marketing

The SDGs as an Operational Framework for Post COVID-19 Response and Recovery

Despite progress on a number of goals, the world was not moving fast enough towards achieving the Sustainable Development Goals in the pre-COVID era. The Decade of Action started with the hit of the COVID-19 crisis, which stressed the urgent need to tack

The Roles of Primary Cilia in Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) is an inherited genetic disorder that results in progressive renal cyst formation with ultimate loss of renal function and other systemic disorders. These systemic disorders include abnormalities in cardiovascular, portal, pancreatic and gastrointestinal systems. ADPKD is considered to be among the ciliopathy diseases due to the association with abnormal primary cilia function. In order to understand the full course of primary cilia and its association with ADPKD, the structure, functions and role of primary cilia have been meticulously investigated. As a result, the focus on primary cilia has emerged to support the vital roles of primary cilia in ADPKD. The primary cilia have been shown to have not only a mechanosensory function but also a chemosensory function. Both structural and functional defects in primary cilia result in cystic kidney disease and vascular hypertension. Thus, the mechanosenory and chemosensory functions will be analyzed in regards to ADPKD

Computation of Flame Base Height of a Turbulent Diffusion Flame Resulting From a Methane Jet

This work summarizes numerical results for a diffusion flame formed from a cylindrical tube fuel injector, issuing a gaseous methane jet vertically in a quiescent atmosphere. The primary objective is to predict the flame base height and other flame characteristics as a function of the fuel jet velocity. A finite volume scheme is used to discretize the time-averaged Navier-Stokes equations for the reacting flow resulting from the turbulent fuel jet motion. The turbulent stresses, and heat and mass fluxes are computed from a Reynolds stress turbulence model. A chemical kinetics model involving two-step chemistry is employed for the oxidation of methane. The reaction rate is determined from a procedure which computes at each point the minimum (process limiting) rate from an Arrhenius (kinetically controlled) expression and the eddy dissipation (turbulent mixing controlled) model. The Reynolds stress model (RSM), in conjunction with the two-step kinetics and the eddy dissipation model, produces flame base height and other flame characteristics that are in good agreement with experimental results. Numerical results are also in agreement with the hypothesis of Van Quickenbourn and van Tiggelen concerning the stabilization mechanism of lifted diffusion flames. The present results show the existence of the condition of tangency, as postulated by Van Quickenbourn and Van Tiggelen, between the jet axial velocity and the flame velocity profiles at the flame base. Furthermore, the burnout rate calculations indicate a high degree of premixing of air and fuel upstream of flame base for moderate to high fuel jet velocity cases