Numerical and experimental investigation of air pollutant dispersion in urban areas

Air pollution is predominantly an urban problem affecting residents living in or around cities. According to the 2014 report of the World Health Organization (WHO), air pollution is now the world’s largest single environmental health risk (WHO 2016). This problem is exacerbated by rapid global population growth (Wania, Bruse et al. 2012), and densely populated urban areas are hotspots of this high risk due to outdoor air pollutant exposure, which also affects indoor air quality. Despite the advancements in urban policies necessary for curtailing air pollutant emissions, it is vital to adopt appropriate strategies in urban planning to manage and reduce outdoor air pollution to minimise the negative impact on public health (Li, Shi et al. 2020). Natural ventilation in the built environment is associated with enhancing outdoor and indoor air quality due to its air pollutant mitigation capacity (Li, Ming et al. 2021). Therefore, natural ventilation capacity deserves special attention from a fundamental perspective, resulting in novel solutions for combating this global problem. This research project focuses on the underlying wind-structure interaction mechanisms involved in the air pollutant dispersion process around buildings. The effect of building cross-section shape and air pollutant density are investigated, and a new fundamental concept of air pollutant emission regions is introduced. The effect of building cross-section shape is further investigated in an idealised generic building cluster based on the fundamental flow structure. Additionally, mean and transient features of air pollutant dispersion based on both continuous air pollutant emission and stagnant air pollutants around a generic isolated building are explored in detail. Finally, two new indices based on air pollutant exposure time in a scaled model are proposed to capture full-scale air pollutant time integrated with air pollutant concentration

Visions of the daughters of Albion: the influence of Mary Wollstonecraft's life and career on William Blake

The present study discussed the influence of one of the eighteenth-century British women of color, the feminist Mary Wollstonecraft, on William Blake. By adopting a biographical and also a comparative approach, the authors tried to highlight the influences of Wollstonecraft's personal life, character, and career, chiefly her A Vindication of the Rights of Woman (1792), on one of William Blake's less-referred-to poems Visions of the Daughters of Albion (1793). The study will help readers to both know Wollstonecraft's prominence and also to grasp more of William Blake and his poetry. The authors also attempted to show that William Blake was part of the early feminism of the late eighteenth century

Aflatoxin contamination in wheat flour samples from Golestan province, Northeast of Iran

Background: Due to the high toxicity of aflatoxin and its effects on public health, determination of aflatoxin level in Wheat flour samples in the Golestan province, north of Iran was investigated. To examine the effect of seasonal changes, summer and winter sampling was performed with standard sampling methods. Methods: A total of 200 flour samples were collected from 25 factories. HPLC method with immunoaffinity chromatography was used to measure aflatoxin types (G2, G1, B2 and B1). Statistical analysis was performed by the Pearson correlation test, One-way ANOVA and multivariate regression analysis. Results: Mean total aflatoxin levels of samples were 0.82 and 1.99 ng/g in summer and winter, respectively. Aflatoxin B1 levels were detected in 3.1%, 7.4% over permissible limits by worldwide regulations in samples collected in summer and winter, respectively. Aflatoxins in winter were higher than summer. The highest frequency of aflatoxin contamination in winter was B2 (98%) and in summer G1 (51%). The relationship between humidity and rate of aflatoxin B1 and total aflatoxin was significant in winter. Results of multivariate regression were showed the strongest relationship with humidity and aflatoxin level. Despite the contamination of flour samples, there was no contamination higher than the standard limit of Iran Standard Institute. But it was significantly higher than similar studies from other regions. Conclusions: Therefore, with regard to negative impacts of aflatoxin on health, aflatoxin contamination should be considered in future programs. Decrease of aflatoxin contamination may be made practical through reducing wheat storage duration and controlling humidity

Fuel saving due to pinch analysis and heat recovery in a petrochemical company

Nowadays, decreasing the amount of natural resources and increasing the price of it, motivates to consider energy conservation as a main concern of many process industries, especially oil, refinery and petrochemical plants. Pinch Analysis (PA) is a powerful method for identifying and selecting technical solution to improve efficiencies and provide an optimum procedure for energy saving. This paper analyses, the effectiveness of applying PA to optimize energy consumption for a given set of process streams in a Petrochemical Company in Iran. In this study, firstly, the interested process streams have been selected, maximum heating and cooling load are computed, and then composite curves have been drawn - by Matlab code - which provides a visual profile of the availability of heating or cooling from the process streams. Secondly, the cost of recovered heat is computed in terms of fuel saving, which confirms applying PA could save significant amount of fuel expenses for the company. Finally, the corresponded Heat Exchanger Network (HEN) has been designed, and the investment costs for heat exchangers have been computed in order to find out payback time of the investment costs which is approximately 17 months for this case study

An Off-design Thermoeconomic Input-Output Analysis of a Natural Gas Combined Cycle Power Plant

In the current and forecasted energy scenario, Natural Gas Combined Cycle (NGCC) power plants are requested increasingly flexible operation. The continuous changes in the capacity factor of the power plants and the increasing number and steepness of ramp-ups could largely affect the thermodynamic and economic performance of the plants and undermine their competitiveness. In order for industrial operators to adopt competitive strategies to increase the flexibility of the power plants, the effect that off-design operation has on the cost structure of plant products needs to be addressed. Thermoeconomics provides tools and models to meet such objective. The study presents an application of Thermoeconomic Input-Output Analysis (TIOA) to a NGCC power plant subject to flexible operation in Italy. The on- and off-design performance of the plant is assessed, considering two load control mechanisms for off-design operation: Inlet Guide Vanes (IGVs) with constant Turbine Outlet Temperature (TOT) or constant Turbine Inlet Temperature (TIT). The Input-Output model is derived from a detailed off-design Thermodynamic model designed in Thermoflow Thermoflex™, and it is stand-alone: it computes the cost structure of the plant products and the Thermoeconomic performance indicators as continuous functions of the gas turbine load, independently from the Thermodynamic model. In the first place, the on- and off-design models of the plant are set up. Secondly, the detailed economic cost analysis is performed. Eventually, the stand-alone Input -Output model is derived: the Technical Coefficients and the Input Coefficients are computed from the fuels and products in the Thermodynamic model at different loads; by regression of the obtained values, continuous functions of the load are derived for each coefficient; finally, the stand-alone model is designed, including these functions in the Leontief Inverse matrix. The results provide an evaluation of the off-design performance of the power plant for the two control strategies, and a tool for the choice of the most efficient one. After specialised analysts set up and run the off-design Thermodynamic model, the power plant operators may perform production scenarios and predictions through the stand-alone Input-Output model independently. This may help abate barriers for industrial practitioners, given by the complexity, computational effort and difficult interpretation of off-design thermodynamic and cost models

Field Research, Research Design and the Tehran Bazaar

With the gradual opening of Iranian society in the second decade after the Islamic Revolution, a number of research centers and networks have been established. Scholarly interest in Iran has also been shifting from examining the causes of the Revolution to investigating its consequences. Scholars are increasingly conducting research based on archival analysis, in-depth interviewing, participant observation and survey analysis to investigate social transformations that have taken place in Iran

PRACTICAL APPROACHES FOR THE APPLICATION OF EXERGY COST THEORY TO ENERGY CONVERSION SYSTEMS

The Exergy Cost Theory (ECT) was proposed as a complete and formalized method to account for the exergy cost of system products, defining criteria for optimization and diagnosis purposes. In this paper, different practical approaches for the application of the Exergy Cost Analysis are presented and comparatively applied to the CGAM problem. An emphasis has been specially put on the possible approaches to define and to solve the system of exergy cost balances, including the definition of auxiliary relations and the reallocation of the exergy cost of residues. It is found that the definition of the functional diagram and the numerical solution of the system through Input-Output analysis seems to be preferable with respect to other approaches