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61.
Kensey Daly Shahryar K. Ahmad Matthew Bonnema Claire Beveridge Faisal Hossain Bart Nijssen Gordon Holtgrieve 《Lakes & Reservoirs: Research and Management》2020,25(2):133-142
Tonle Sap Lake in Cambodia is arguably the world's most productive freshwater ecosystems, as well as the dominant source of animal protein for the country. The rapid rise of hydropower schemes, deforestation, land development and climate change impacts in the Mekong River Basin, however, now represent serious concerns in regard to Tonle Sap Lake's ecological health and its role in future food security. To this end, the present study identifies significant recent warming of lake temperature and discusses how each of these anthropogenic perturbations in Tonle Sap's floodplain and the Mekong River Basin may be influencing this trend. The lake's dry season monthly average temperature increased by 0.03°C/year between 1988 and 2018, being largely in synchrony with warming trends of the local air temperature and upstream rivers. The impacts of deforestation and agriculture development in the lake's floodplain also exhibited a high correlation with an increased number of warm days observed in the lake, particularly in its southeast region (agriculture R2 = .61; deforestation R2 = .39). A total of 79 dams, resulting in 72 km3 of volumetric water capacity, were constructed between 2003 and 2018 in the Mekong River Basin. This dam development coincided with a decreasing trend in the number of dry season warm days per year in the lower Mekong River, while Tonle Sap Lake's number of dry season warm days continued to increase during this same period. The present study revealed that Tonle Sap Lake's temperature trends are highly influenced by temperature trends in the local climate, agriculture development and deforestation of the lake's watershed. Although there were no noticeable impacts observed from upstream dam development in the Mekong River Basin, local‐to‐regional agricultural and land management of the lake's watershed appear to be effective strategies for maintaining a stable thermal regime in the lake in order to facilitate maximum ecosystem health. 相似文献
62.
Drying of hot chilli using solar tunnel drier 总被引:3,自引:1,他引:3
A mixed mode type forced convection solar tunnel drier was used to dry hot red and green chillies under the tropical weather conditions of Bangladesh. The drier consisted of transparent plastic covered flat-plate collector and a drying tunnel connected in series to supply hot air directly into the drying tunnel using two fans operated by a photovoltaic module. The drier had a loading capacity of 80 kg of fresh chillies. Moisture content of red chilli was reduced from 2.85 to 0.05 kg kg−1 (db) in 20 h in solar tunnel drier and it took 32 h to reduce the moisture content to 0.09 and 0.40 kg kg−1 (db) in improved and conventional sun drying methods, respectively. In case of green chilli, about 0.06 kg kg−1 (db) moisture content was obtained from an initial moisture content of 7.6 kg kg−1 (db) in 22 h in solar tunnel drier and 35 h to reach the moisture content to 0.10 and 0.70 kg kg−1 (db) in improved and conventional sun drying methods, respectively. The use of a solar tunnel drier and blanching of sample led to a considerable reduction in drying time and dried products of better quality in terms of colour and pungency in comparison to products dried under the sun. The solar tunnel drier and blanching of chilli are recommended for drying of both red and green chillies. 相似文献
63.
The materials characterisation requirements for accurate yet practical simulation of daylighting in buildings is examined for a range of emerging and existing technologies which seek to raise the contribution of daylighting to overall lighting requirements. Algorithms based on underlying physical models can be established from analysis of data on bi-directional transmission and reflection. Demonstrations of effects in simulation relevant to glare, view and illuminance are given. 相似文献
64.
A range of point process models which are commonly used in spatial epidemiology applications for the increased incidence of disease are compared. The models considered vary from approximate methods to an exact method. The approximate methods include the Poisson process model and methods that are based on discretization of the study window. The exact method includes a marked point process model, i.e., the conditional logistic model. Apart from analyzing a real dataset (Lancashire larynx cancer data), a small simulation study is also carried out to examine the ability of these methods to recover known parameter values. The main results are as follows. In estimating the distance effect of larynx cancer incidences from the incinerator, the conditional logistic model and the binomial model for the discretized window perform relatively well. In explaining the spatial heterogeneity, the Poisson model (or the log Gaussian Cox process model) for the discretized window produces the best estimate. 相似文献
65.
Ali Kadkhodaie-Ilkhchi Hossain Rahimpour-Bonab Mohammadreza Rezaee 《Computers & Geosciences》2009,35(3):459-474
Total organic carbon (TOC) content present in reservoir rocks is one of the important parameters, which could be used for evaluation of residual production potential and geochemical characterization of hydrocarbon-bearing units. In general, organic-rich rocks are characterized by higher porosity, higher sonic transit time, lower density, higher γ-ray, and higher resistivity than other rocks. Current study suggests an improved and optimal model for TOC estimation by integration of intelligent systems and the concept of committee machine with an example from Kangan and Dalan Formations, in South Pars Gas Field, Iran. This committee machine with intelligent systems (CMIS) combines the results of TOC predicted from intelligent systems including fuzzy logic (FL), neuro-fuzzy (NF), and neural network (NN), each of them has a weight factor showing its contribution in overall prediction. The optimal combination of weights is derived by a genetic algorithm (GA). This method is illustrated using a case study. One hundred twenty-four data points including petrophysical data and measured TOC from three wells of South Pars Gas Field were divided into 87 training sets to build the CMIS model and 37 testing sets to evaluate the reliability of the developed model. The results show that the CMIS performs better than any one of the individual intelligent systems acting alone for predicting TOC. 相似文献
66.
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68.
Oil-water interfacial tension measurements are reported for systems of crude oils, distilled and salt water, and chemical dispersants, using the spinning drop technique. By varying the amount of dispersant and the volumetric ratio of water to oil it is possible to deduce an effective oil-water partition coefficient for the interfacial tension reducing species and to suggest a relationship between the extent of interfacial tension reduction and dispersant concentration. The implications of the results in assessing the mechanism and effectiveness of the chemical dispersion process are discussed. 相似文献
69.
S. M. Zakir Hossain 《化学工程与技术》2019,42(12):2594-2607
Biofuel production via microalgae is a promising and sustainable alternative to replace the typical fossil fuel that is the main contributor to the global warming. However, for a cost‐effective biofuel production, further advanced research is still needed for large‐scale operation. This article is a tutorial review on conversion processes of microalgae into biofuel, with emphasis on biochemical conversion. The following topics are discussed: (i) microalgae biomass and its composition, (ii) thermochemical conversion, (iii) chemical conversion, and (iv) biochemical conversion. In addition, various aspects of anaerobic digestion, digester designs, and effects of operating conditions on the production of methane, bioethanol, and biohydrogen are discussed. The general kinetics of biomass conversion into biofuel is presented. This study suggests, if that biomass contains less than 50 % moisture, then it is recommended to use the direct combustion method; otherwise, biochemical conversion is the most suitable process to biofuel production. 相似文献
70.
K. Raleva D. Vasileska A. Hossain S.-K. Yoo S. M. Goodnick 《Journal of Computational Electronics》2012,11(1):106-117
In this paper we present a study of self-heating effects in nanoscale SOI (Silicon-On-Insulator) devices and conventional
MOSFETs using an in-house electro-thermal particle-based device simulator. We first describe the key features of the electro-thermal
Monte Carlo device simulator (the two-dimensional (2D) and the three-dimensional version (3D) of the tool) and then we present
a series of representative simulation results that clearly illustrate the importance of self-heating in larger nanoscale devices
made in SOI technology. Our simulation results for planar SOI devices (using 2D version of the tool) show that in the smallest
devices considered, heat dissipation occurs in the contacts, not in the active channel region of the device. This is because
of two factors: pronounced velocity overshoot effect and the smaller thermal resistance of the buried oxide layer. We propose
methods in which heat can be effectively removed from the device by using silicon on diamond and silicon on AlN technologies.
To simulate self heating in nanowire transistors, the 2D simulator was extended to three spatial dimensions. We study the
interplay of Coulomb interactions due to the presence of a random trap at the source end of the channel in nanowire transistors,
the influence of a positive and a negative trap on the magnitude of the on-current and the role of the potential barrier at
the source end of the channel. Finally, we examine the importance of self-heating effects in conventional MOSFETs used for
low-power applications. We find that the average temperature increase obtained with our simulator of about 10 K is almost
identical to the value that has to be used in low-power circuit simulations. 相似文献