A polygonal curve is simplified to reduce its number of vertices, while maintaining similarity to its original shape. Numerous results have been published for vertex-restricted simplification, in ...which the vertices of the simplified curve are a subset of the vertices of the input curve. In curve-restricted simplification, i.e. when the vertices of the simplified curve are allowed to be placed on the edges of the input curve, the number of vertices may be much more reduced. In this paper, we present algorithms for computing curve-restricted simplifications of polygonal curves under the local Hausdorff distance measure.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
•Drought induces osmoregulation in fennel.•Exogenous proline enhances osmoregulation.•Genotypic variation exists in fennel’s response to proline.•Drought and exogenous proline increase fennel’s ...essential oil concentration.
Proline is an amino acid with pivotal role in plant responses to environmental constraints. Effects of its foliar application (20mM) on physiological functions of 12 fennel (Foeniculum vulgare Mill.) genotypes at the presence of different moisture conditions (non-stress control and drought stress) was studied in a 2-year field study. Drought led to notable increases in mean leaf polyphenol, proline and total soluble carbohydrates and essential oil concentrations, despite decreases in carotenoids and chlorophyll concentrations, leaf water potential, relative water content, plant above-ground dry mass and water use efficiency. Exogenous proline resulted in significant increases in mean carotenoids, polyphenol, chlorophyll, proline, total soluble carbohydrates and essential oil concentrations and relative water content, but it caused a decrease in leaf water potential. Proline amendment positively affected plant water relations, due mostly to enhancement in osmoregulation, as certain genotypes with greater mean leaf proline concentration and relative water content appeared to produce greater above-ground dry mass, when exposed to the external proline. Ameliorative effects of exogenous proline tended to be greater in drought-stressed plants, as it led to the enhancement of chlorophyll concentration and relative water content of fennel in drought conditions. Genotypes Urmia and Yazd were found to be able to withstand better against drought and benefit more from external proline. Our findings suggest that while indigenous proline is the most sensitive osmoticum in fennel’s response to drought, its external amendment may bring about improvements in water relations and osmoregulatory measure in this medicinal plant.
The hydrogen peroxide (H
O
) measurement is considered highly important in industrial wastewater quality assessment, environmental protection, and disease detection. Here, a simple high-performance ...paper-based sensor is proposed for rapid and in situ detection of H
O
. To this end, 3,3',5,5'-tetramethylbenzidine is embedded in the sensor to act as a color indicator, whose reaction with hydrogen peroxide is catalyzed by a silver nanozyme modified by sericin. The result of the reaction clarified by the appearance of blue color in the sensor detection zone is received by a portable scanner, while also calculating its intensity by image analysis software. This method is sensitive to hydrogen peroxide in the concentration range of 0.5‒240 mg/dL, providing a detection limit of 0.15 mg/dL. The ability of the sensor to determine glucose is also evaluated by adding a layer containing glucose oxidase enzyme to the sensor structure. A desirable response is obtained in the range of 1.0‒160 mg/dL, together with a detection limit of 0.37 mg/dL. Accordingly, the proposed sensor shows satisfactory results compared to clinical methods for monitoring the amount of glucose in biological samples such as serum and saliva.
This study used sodium sulfate decahydrate (Na2SO4.10H2O) with different masses as a PCM. Thermal conductivity was improved by using rigid blades and heated sinks instead of flexible blades behind ...the panel. The results show a positive effect of fixed blades and heatsinks on temperature parameters and panel efficiency. The test was performed in the radiation range of 800 W/m2 at an angle of 35° to the horizon. During the last 70 min of the test, the panel containing phase change material and fixed blades, even after the test was over, had the same temperature as the standard panel. The temperature difference was 11.5 °C compared to the standard panel. In addition, the maximum efficiency difference between the panel with the material of the phase change and the panel with a fixed blade of the phase-changing material with a conventional panel was 3.05% and 6.17%, respectively. Furthermore, mass analysis of PCM reveals that the melting point increases by 50% of the initial mass of the phase material, resulting in a maximum temperature difference of 7.5 °C on the panel surface, a maximum efficiency difference of 2.34%.
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•Analysis of the vegetation trends for different land cover types.•Determination of areas suitable for future restoration projects.•Reforestation, sand dunes and clay pits are the ...most favorable for restoration projects.•Assessment of the restoration areas according to topography and climatic type.
This study examines the trends in vegetation cover using the Growing Season NDVI (GSN) time series in moderate spatial resolution (250 m) over Khorasan Razavi province, in northeast Iran, during the period 2004–2015. The province is largely desert, with extra-arid, arid, and semi-arid de Martonne climate zones dominating, while rangelands, shrublands and deserts cover most areas, making it an ideal territory for monitoring vegetation trends and implement future restoration projects. Most parts of the province and land-cover classes show no trends in vegetation cover, but large decreasing trends occur in areas covered by sand dunes, previously reforested lands and clay pit areas. Trends in various land-cover types are also examined as functions of the climatic class and the Terrain Niche index (TNI), which is characteristic of the topography, revealing large decreasing trends in the extra-arid climatic zone. In addition, most of the areas exhibit Hurst exponent values around 0.5, implying stochastic time series without any consistency and a likelihood of random vegetation and land cover changes in the future. This study also aims to determine likely future vegetation status and the most favourable areas for restoration projects through analysis of two indexes (Future Restoration Dispersal Index, FRDI and Future Uncertainty Dispersal Index, FUDI). The results show that reforestation, sand dunes and clay pits areas are the most favourable for implementing restoration projects, while the spatial distribution of the potential restoration classes reveals that the southern and northeastern parts of Khorasan Razavi province are the most favourable areas for establishing environmental restoration activities in order to avoid further degradation of ecosystems.
One of the most important types of emerging micropollutants is the pharmaceutical micropollutant. Pharmaceutical micropollutants are usually identified in several environmental compartments, so the ...removal of pharmaceutical micropollutants is a global concern. This study aimed to remove diclofenac (DCF), ibuprofen (IBP), and naproxen (NPX) from the aqueous solution via cross-linked magnetic chitosan/activated biochar (CMCAB). Two independent factors—pH (4–8) and a concentration of emerging micropollutants (0.5–3 mg/L)—were monitored in this study. Adsorbent dosage (g/L) and adsorption time (h) were fixed at 1.6 and 1.5, respectively, based on the results of preliminary experiments. At a pH of 6.0 and an initial micropollutant (MP) concentration of 2.5 mg/L, 2.41 mg/L (96.4%) of DCF, 2.47 mg/L (98.8%) of IBP, and 2.38 mg/L (95.2%) of NPX were removed. Optimization was done by an artificial neural network (ANN), which proved to be reasonable at optimizing emerging micropollutant elimination by CMCAB as indicated by the high R2 values and reasonable mean square errors (MSE). Adsorption isotherm studies indicated that both Langmuir and Freundlich isotherms were able to explain micropollutant adsorption by CMCAB. Finally, desorption tests proved that cross-linked magnetic chitosan/activated biochar might be employed for at least eight adsorption-desorption cycles.
We study the problem of finding hotspots, i.e. regions, in which a moving entity spends a significant amount of time, for polygonal trajectories. The fastest exact algorithm, due to Gudmundsson, van ...Kreveld, and Staals (2013) finds an axis-parallel square hotspot of fixed side length in O(n2) for a trajectory with n edges. Limiting ourselves to the case in which the entity moves in a direction parallel either to the x or to the y-axis, we present an approximation algorithm with the time complexity O(n log3 n) and approximation factor 1/2.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Understanding the trends of reference evapotranspiration (ETo) and its influential meteorological variables due to climate change is required for studying the hydrological cycle, vegetation ...restoration, and regional agricultural production. Although several studies have evaluated these trends, they suffer from a number of drawbacks: (1) they used data series of less than 50 years; (2) they evaluated the individual impact of a few climatic variables on ETo, and thus could not represent the interactive effects of all forces driving trends of ETo; (3) they mostly studied trends of ETo and meteorological variables in similar climate regions; (4) they often did not eliminate the impact of serial correlations on the trends of ETo and meteorological variables; and finally (5) they did not study the extremum values of meteorological variables and ETo. This study overcame the abovementioned shortcomings by (1) analyzing the 50-year (1961–2010) annual trends of ETo and 12 meteorological variables from 18 study sites in contrasting climate types in Iran, (2) removing the effect of serial correlations on the trends analysis via the trend-free pre-whitening approach, (3) determining the most important meteorological variables that control the variations of ETo, and (4) evaluating the coincidence of annual extremum values of meteorological variables and ETo. The results showed that ETo and several meteorological variables (namely wind speed, vapor pressure deficit, cloudy days, minimum relative humidity, and mean, maximum and minimum air temperature) had significant trends at the confidence level of 95% in more than 50% of the study sites. These significant trends were indicative of climate change in many regions of Iran. It was also found that the wind speed (WS) had the most significant influence on the trend of ETo in most of the study sites, especially in the years with extremum values of ETo. In 83.3% of the study sites (i.e., all arid, Mediterranean and humid regions and 66.7% of semiarid regions), both ETo and WS reached their extremum values in the same year. The significant changes in ETo due to WS and other meteorological variables have made it necessary to optimize cropping patterns in Iran.
For a map that can be rotated, we consider the following problem. There are a number of feature points on the map, each having a geometric object as a label. The goal is to find the largest subset of ...these labels such that when the map is rotated and the labels remain vertical, no two labels in the subset intersect. We show that, even if the labels are vertical bars of zero width, this problem remains NP-hard, and present a polynomial approximation scheme for solving it. We also introduce a new variant of the problem for vertical labels of zero width, in which any label that does not appear in the output must be coalesced with a label that does. Coalescing a subset of the labels means to choose a representative among them and set its label height to the sum of the individual label heights.
The immiscibility of oil and alcohol is a severe issue in biodiesel production as it causes a low mass transfer rate and long reaction time. This problem can be overcome by incorporating the ...intensification method, which significantly increases the contact surface area of oil and alcohol through various techniques. In recent years, ultrasonic cavitation has emerged as one of the most effective ways for this purpose. However, it is still unclear whether this technology will provide the industry with an economically profitable process. This paper attempts to assess the potential of ultrasonic cavitation from a techno-economic viewpoint. Two plants based on the conventional mechanical stirring and ultrasonic cavitation processes were designed using Aspen HYSYS V8.4. Total investment, costs of products, net present value, and internal rate of return were used to compare the two processes together. The total investment in the ultrasonic cavitation process was lower than that of the mechanical stirring process by approximately 20.8%. Compared to the conventional process, using ultrasonic reactors also caused products’ costs to reduce by 5.2%. Owing to a positive net present value and an internal rate of return of 18.3%, the ultrasonic cavitation process was a better choice. Moreover, ultrasonic cavitation resulted in a meaningful decrease in both consumed energy and the production of wastes. The overall energy consumption was reduced by 6.9% when ultrasonic cavitation was employed. The amount of waste produced in the ultrasound-assisted process was one-fifth of that in the mechanical stirring process.
•Conventional mechanical stirrer & ultrasonic cavitation biodiesel production processes were designed.•Total capital investment, total product cost, net present value and internal rate of return were used to compare together.•The amount of total investment in the ultrasonic cavitation process was found to be lower than that of other by approximately 20.8%.•Using ultrasonic reactors also caused the costs of products to reduce by 5.2%.•Owing to a positive net present value, the ultrasonic cavitation process was a better choice.
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