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To meet the increasing demands of precision agricultural and environmental management, more abundant and accurate information is needed to describe soil organic carbon (SOC) vertical variation. Based on 923 soil profiles (collected at the depths of 0–15, 15–30, 30–60, 60–90, 90–120, and 120–150 cm) in the central area of Changhua County, Taiwan, the distribution curve of the SOC content of each profile was fitted by the equal-area spline model, and it was possible to obtain the SOC content at all depths. Taking the 0–5 cm (L1), 5–10 cm (L2), and 10–15 cm (L3) sub-layers as examples, their SOC contents and stocks were compared to the mean values of the average 5-cm-thick sub-layers (Lm) derived from the value of the 0–15 cm layer. The results indicated that the SOC contents and stocks both reduced with increasing soil depths. The mean SOC contents of L1, L2, and L3 were 22.1, 21.0, and 18.7 g·kg−1, respectively, with significant variation, and the values of L2 and L3 were 5.0% and 15.4% lower than that of L1. Similarly, the mean SOC stocks were 1.29, 1.25, and 1.16 kg·m−2 of the L1, L2, and L3 layers, also with significant variation, and the values of L2 and L3 were 4.0% and 10.1% lower than that of L1. Meanwhile, it was found that the SOC content and stock of Lm were both close to the corresponding values in L2, but were significantly different to that of L1 and L3. Furthermore, the interpolation contours of the SOC contents and stocks in L1, L2, and L3 by digital soil mapping also presented regular variation with increasing soil depths, while the contours of Lm had nearly identical patterns to that of L2. The results demonstrate that the typically used mean SOC contents with certain thicknesses calculated from the sampling layer can only approximately inflect the SOC situation at intermediate depths, but the SOC content in the upper and lower parts within the sampling layer varies greatly. Therefore, the actual distribution of SOC varies gradually depending on the soil depth. This study indicates that the combination of the equal-area spline model and digital soil mapping can greatly enrich the current soil SOC database and provide more abundant and accurate SOC content and stock information for precision agricultural and environmental management based on legacy soil database.

ABSTRACTThe goal of this study was to analyse the combustion characteristics and emissions of Jatropha curcas biodiesel (JCB) when run in a diesel engine. Jatropha curcas oil was used to produce Jatropha curcas biodiesel (JCB) through a transesterification process. The major fuel properties of JCB, including the acid value, kinematic viscosity, flash point, gross heating value, and iodine value, were determined and compared with that of soybean biodiesel (SBM), sunflower seed biodiesel (SFM), mackerel fish oil biodiesel (MB), and premium diesel (D). JCB had a higher density, acid value, kinematic viscosity, iodine value and flash point, but a lower gross heating value, than D. JCB was then used to analyze combustion characteristics, CO, CO2, NO, NOx, SO2, and particulate matter (PM), under varied engine speeds and varied engine loads. The experimental results show CO2 concentration increased with increasing engine loads for all fuels. Engine trials on D exhibited better combustion efficiency at lower engine loads (0 kW–4 kW) but engine trials on JCB exhibited better combustion efficiency for higher engine loads (5 kW– 8 kW). JCB emitted more NO and NOx on a loaded engine. Engine trials on JCB emitted higher PM concentration when the engine was not loaded, while engine trials on MB produced higher PM concentration when the engine was loaded. The estimated CO2 emissions for JCB, MB, and D are 9221.3, 9617.2, and 10185.0 g (gal fuel)–1, respectively.

To cope with global warming and environmental protection in recent years, the requirements for clean energy are enhancing, and the installation of wind power, as one of such energy, is increasing in various countries. Nevertheless, the connection of wind blades and support blades often break when wind turbine are running. To avoid such a problem in the design stage or the successive reinforcement through proper methods has become an urgent problem in engineering. Commercial software, Solidworks Simulation, is used for simulating stress distribution and the patch reinforcement design in this paper. The analyses show that the maximum stress of the original design not being reinforced with patches has exceeded the tensile strength of the material and result in the breaks and damage of the entire structure. Using composite patches to reinforce the interface of wind blades and the supportive structure could effectively reduce the maximum stress and the displacement of deformation. Moreover, patches could effectively reduce the maximum stress that the optimal reinforcement should take a larger fillet into account.

This research enhances the previous control method by utilizing an embedded controller (EC) to create a fuzzy logic controller (FLC) to reduce the power consumption of a notebook or netbook and to lengthen the battery life. Our control methods are all written in assembly language, so that there is no need to rely on any high-level application program for the FLC. Thus our design has greater efficiency and accelerates the pace of operations. We add a CPU throttle function in connection with the FLC to control the clock frequency of the CPU. This design reduces power consumption and lengthens battery life. The low-power embedded controller in a notebook is a device to assist the onboard power management system which consists of the cooling fan, the keyboard, the LCD backlight brightness and the battery recharging functions. By using the fuzzy control rule as a replacement of the default method, the fan speed becomes variable so as to maintain a certain range of temperature of the mobile computer. The LCD backlight brightness is adjusted and based on the keystroke frequency or the touchpad controlled by the FLC of our design.

Abstract In this study, two types of the counter electrode were designed and fabricated for the dye-sensitized solar cell (DSSC): (1) one had a layer of SWCNT/Ag on the FTO-glass (Fluorine doped tin oxide, SnO 2 :F) substrate; (2) the other had a layer Ag sandwiched between a layer of SWCNT and the FTO-glass substrate. This study also examined the effects of the mass ratio of SWCNT to Ag-paste, the surfactant (such as TOAB), the type of FTO-glass substrate, and the sintering temperature of preparing the counter electrode on the short-circuit photocurrent and the open-circuit photovoltage of the DSSC. At a fixed sintering temperature of 150 °C and a fixed FTO-glass substrate of 8 Ω/sq, this film of SWCNT markedly increased the short-circuit photocurrent from 227.3 μA (conventional DSSC without a layer of SWCNT) to 1033.5 μA (DSSC with a layer of SWCNT/Ag). Most importantly, at a fixed FTO-glass substrate of 8 Ω/sq, this study shows that the short-circuit photocurrent of the DSSC with a layer Ag sandwiched between a layer of SWCNT and the FTO-glass substrate of the counter electrode (2565 μA) substantially exceeds that of DSSC with a thin film of platinum on the FTO-glass substrate of the counter electrode (1263.7 μA).

This study developed a model that examined the relationship between undergraduate students’ beliefs, norms and pro-environment behavioral intentions in the context of global climate change (GCC). The model was further evaluated to determine whether latent variables, such as sustainability value, environmental concern, social norms, perceived risk, pro-environmental attitude, as defined by the theory of planned behavior and value-belief-norm theory, significantly influenced students’ intentions towards pro-environmental behavior. The research model was empirically tested using data collected form 275 undergraduate students. Empirical results found support for four interaction effects of personality traits and the related latent variables of environmental attitude, including sustainability value, social norms, environmental concern and perceived risk. The impact of undergraduate students’ environmental attitudes was moderated by personality traits. The findings of this research offer policy makers and enterprises better understandings of undergraduate students’ attitudes and behavioral intentions towards GCC and promote the visibility of this issue.

The aim of this paper is to investigate the threshold effect of foreign direct investment (FDI) on environmental degradation. In empirical analysis, FDI and environmental degradation are jointly determined under the given threshold variable and other exogenous variables. Using carbon dioxide (CO2) emissions per capita as a proxy for environmental degradation, the results show that increasing FDI worsens CO2 emissions after a threshold level of corruption has been reached. Our results demonstrate that increasing FDI will increase CO2 emissions when the degree of corruptibility is relatively high. The study suggests that further FDI and improved environmental quality are competing rather than compatible objectives in high-corruption countries and are compatible rather than competing objectives in low-corruption countries. Higher trade liberalization in low-corruption countries could contribute to negative environmental consequences because of the increased output or economic activity which results from increased trade. The robustness estimation confirms the evidence that pollution and economic development increase together up to a certain income level, after which the trend reverses.

This study analyzes transient turbulent modeling of three-dimensional multiple dimpled fin array using large eddy simulation (LES). The Navier–Stokes equations as well as the energy equation were constructed by the finite volume method and then discretized to form algebraic equations, which were solved by semi-implicit method for pressure-linked equation (SIMPLE). The solutions of temperature and velocity were obtained by iterating computation until it converged within each step. This simulation places nine fins on the bottom surface of a channel and changes the height of the dimple (0.4, 0.8, and 1.2 mm) with three different levels of Reynolds number (Re) (3500, 5000, and 6500) to investigate the temperature and flow field without gravity in forced convection. The results indicate that the dimpled fin array can generate vortices between the convex/concave dimples and the fin base and increase the influences of the height of the dimple on the flow field around the fin array. The averaged time-mean of the Nusselt number (Nu) for the dimple height of 0.8 mm is higher than that of the no-dimple case up to 14.4%, while the averaged time-mean Nu for the dimple height of 1.2 mm is lower than that of the no-dimple case up to 11.6%.