The performance of a BTES （borehole thermal energy storage） system is primarily governed by ground heat flux, soil thermal properties and groundwater conditions. However, the design of the heat exchanger used within...The performance of a BTES （borehole thermal energy storage） system is primarily governed by ground heat flux, soil thermal properties and groundwater conditions. However, the design of the heat exchanger used within the BTES system can also make a significant difference in the efficiency of the system. A thermal response test was carded out for a Kelix GHE （ground heat exchanger） system, the latest innovation in geothermal ground loop construction, on an Ecofarm in the town of Caledon East, Ontario, Canada. In addition, a verifying test was performed for a CEES （conventional earth energy system） located 6 m away from the Kelix GHE. The boreholes for these two different heat exchanger designs were drilled with the same diameter, to the same depth and were located in the same/identical geo-hydrological conditions. The response test provided the effective average of undisturbed ground temperature, geothermal properties including thermal conductivity, heat capacity and thermal resistance between the fluid and the borehole wall. The mathematical analysis method used for the response test is presented here. Results of the response test were verified, analyzed and are further discussed.展开更多
A novel experimental setup was developed to study the heat extraction of geothermal heat exchanger(GHE)in different operational modes under adiabatic and isothermal boundaries.The experimental setup consists of a sand...A novel experimental setup was developed to study the heat extraction of geothermal heat exchanger(GHE)in different operational modes under adiabatic and isothermal boundaries.The experimental setup consists of a sand trunk,a tailored water chiller,a natural cold source unit,two water boxes containing hot water and cool water,and a data acquisition system.The experimental results indicate that the volume flow rate of the entering water is a main factor affecting the heat extraction;furthermore,the heat extraction value per meter pipe decreases gradually along the heat extraction pipe and increases with the increase of the incoming water volume flow rate.Therefore,this novel experimental setup may be helpful to further study the operation performance of GHE in different types of soil.展开更多
This research aims to improve the efficiency in estimating the Hurst exponent in financial time series.A new procedure is developed based on equality in distribution and is applicable to the estimation methods of the ...This research aims to improve the efficiency in estimating the Hurst exponent in financial time series.A new procedure is developed based on equality in distribution and is applicable to the estimation methods of the Hurst exponent.We show how to use this new procedure with three of the most popular algorithms(generalized Hurst exponet,total triangles area,and fractal dimension)in the literature.Findings show that this new approach improves the accuracy of the original methods,mainly for longer series.The second contribution of this study is that we show how to use this methodology to test whether the series is self-similar,constructing a confidence interval for the Hurst exponent for which the series satisfies this property.Finally,we present an empirical application of this new procedure to stocks of the S&P500 index.Similar to previous contributions,we consider this to be relevant to financial literature,as it helps to avoid inappropriate interpretations of market efficiency that can lead to erroneous decisions not only by market participants but also by policymakers.展开更多
This paper investigates the impact of climate change on human health in Nigeria. The paper relies on secondary data, sourced from journals, government documents and private individuals. From these sources the paper di...This paper investigates the impact of climate change on human health in Nigeria. The paper relies on secondary data, sourced from journals, government documents and private individuals. From these sources the paper discovered that climate change poses a wide range of health risks to human health which include direct effects on human health resulting from increase in temperature and amplified air pollution that increase in temperature needs high incidence of vector-borne diseases such as malaria, dysentery and cholera among others. Climate change also leads to rising sea levels which contaminates coastal fresh water and makes low-lying areas vulnerable to flooding. Flooding results in frequent incidences of malaria, cholera, typhoid to mention but few. It also leads to the displacement of people and resource conflicts, e.g., land and water, and post-disaster mental health problem. Finally the paper suggests that after flooding, affected settlements should be fumigated before people pack tack in order to reduce the incidences of cholera, malaria and dysentery among others, and that to reduce the discharge of carbon into the atmosphere alternative source of energy to fuel wood, must be put in place by the government.展开更多
文摘The performance of a BTES （borehole thermal energy storage） system is primarily governed by ground heat flux, soil thermal properties and groundwater conditions. However, the design of the heat exchanger used within the BTES system can also make a significant difference in the efficiency of the system. A thermal response test was carded out for a Kelix GHE （ground heat exchanger） system, the latest innovation in geothermal ground loop construction, on an Ecofarm in the town of Caledon East, Ontario, Canada. In addition, a verifying test was performed for a CEES （conventional earth energy system） located 6 m away from the Kelix GHE. The boreholes for these two different heat exchanger designs were drilled with the same diameter, to the same depth and were located in the same/identical geo-hydrological conditions. The response test provided the effective average of undisturbed ground temperature, geothermal properties including thermal conductivity, heat capacity and thermal resistance between the fluid and the borehole wall. The mathematical analysis method used for the response test is presented here. Results of the response test were verified, analyzed and are further discussed.
基金Sponsored by the National Natural Science Foundation of China (Grant No. 50378024)
文摘A novel experimental setup was developed to study the heat extraction of geothermal heat exchanger(GHE)in different operational modes under adiabatic and isothermal boundaries.The experimental setup consists of a sand trunk,a tailored water chiller,a natural cold source unit,two water boxes containing hot water and cool water,and a data acquisition system.The experimental results indicate that the volume flow rate of the entering water is a main factor affecting the heat extraction;furthermore,the heat extraction value per meter pipe decreases gradually along the heat extraction pipe and increases with the increase of the incoming water volume flow rate.Therefore,this novel experimental setup may be helpful to further study the operation performance of GHE in different types of soil.
基金supported by grants PGC2018-101555-B-I00(Ministerio Español de Ciencia,Innovación y Universidades and FEDER),PID2021-127836NB-I00(Ministerio Español de Ciencia e Innovación and FEDER)and UAL18-FQM-B038-A(UAL/CECEU/FEDER).
文摘This research aims to improve the efficiency in estimating the Hurst exponent in financial time series.A new procedure is developed based on equality in distribution and is applicable to the estimation methods of the Hurst exponent.We show how to use this new procedure with three of the most popular algorithms(generalized Hurst exponet,total triangles area,and fractal dimension)in the literature.Findings show that this new approach improves the accuracy of the original methods,mainly for longer series.The second contribution of this study is that we show how to use this methodology to test whether the series is self-similar,constructing a confidence interval for the Hurst exponent for which the series satisfies this property.Finally,we present an empirical application of this new procedure to stocks of the S&P500 index.Similar to previous contributions,we consider this to be relevant to financial literature,as it helps to avoid inappropriate interpretations of market efficiency that can lead to erroneous decisions not only by market participants but also by policymakers.
文摘This paper investigates the impact of climate change on human health in Nigeria. The paper relies on secondary data, sourced from journals, government documents and private individuals. From these sources the paper discovered that climate change poses a wide range of health risks to human health which include direct effects on human health resulting from increase in temperature and amplified air pollution that increase in temperature needs high incidence of vector-borne diseases such as malaria, dysentery and cholera among others. Climate change also leads to rising sea levels which contaminates coastal fresh water and makes low-lying areas vulnerable to flooding. Flooding results in frequent incidences of malaria, cholera, typhoid to mention but few. It also leads to the displacement of people and resource conflicts, e.g., land and water, and post-disaster mental health problem. Finally the paper suggests that after flooding, affected settlements should be fumigated before people pack tack in order to reduce the incidences of cholera, malaria and dysentery among others, and that to reduce the discharge of carbon into the atmosphere alternative source of energy to fuel wood, must be put in place by the government.
