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[en] The concepts of the cities we know nowadays, and which we are accustomed to, change at a very rapid pace. The philosophy of their design is also changing. It will base on new standards, entering a completely different, futuristic dimension. This stage is related to changes in the perception of space, location and lack of belonging to definite, national or cultural structures. Cities of the future are cities primarily intelligent, zero-energetic, zero-waste, environmentally sustainable, self-sufficient in terms of both organic food production and symbiosis between the environment and industry. New cities will be able to have new organisational structures—either city states, or, apolitical, jigsaw-like structures that can change their position—like in the case of the city of Artisanopolis, designed as a floating city, close to the land, reminiscent of the legendary Atlantis. This paper is focused on the main issues connected with problems of the contemporary city planning. The purpose of the research was to identify existing technological solutions, whose aim is to use solar energy and urban greenery. The studies were based on literature related to future city development issues and futuristic projects of the architects and city planners. In the paper, the following issues have been verified: futuristic cities and districts, and original bionic buildings, both residential and industrial. The results of the analysis have been presented in a tabular form.
[en] High power tapered lasers are designed and fabricated. A one-dimensional photonic crystal structure in the vertical direction is adopted to narrow the far field divergence. The thickness of the defect layer and the photonic crystal layers are optimized by analyzing the optical field theoretically. For tapered lasers, the continuous-wave power is 7.3 W and the pulsed power is 17 W. A maximum wall-plug efficiency of 46% under continuous-wave operation and 49.3% in pulsed mode are obtained. The beam divergences are around 11° and 6° for the vertical and lateral directions, respectively. High beam qualities are also obtained with a vertical M2 value of 1.78 and a lateral M2 value of 1.62. As the current increases, the lateral M2 value increases gradually while the vertical M2 value remains around 2. (paper)
[en] The participation of renewables sources of energy in the Brazilian Energy generation mix is among the highest in the world. The Brazilian government has been striving to develop clean energy generation projects and to diversify the electricity matrix, which is strongly dependent of hydropower. This paper gives an overview of recent activities aimed at the development of nuclear power as effective option for collaborate with the diversification of the Brazilian energy mix, mitigate the impacts from climate change and democratize the population's access to electricity throughout a continental country territory.
[en] This study investigated trends in 35 years (1979–2013) temperature (maximum, Tmax and minimum, Tmin) and rainfall at annual and seasonal (pre-monsoon, monsoon, post-monsoon, and winter) scales for 31 grid points in a coastal arid region of India. Box-whisker plots of annual temperature and rainfall time series depict systematic spatial gradients. Trends were examined by applying eight tests, such as Kendall rank correlation (KRC), Spearman rank order correlation (SROC), Mann-Kendall (MK), four modified MK tests, and innovative trend analysis (ITA). Trend magnitudes were quantified by Sen’s slope estimator, and a new method was adopted to assess the significance of linear trends in MK-test statistics. It was found that the significant serial correlation is prominent in the annual and post-monsoon Tmax and Tmin, and pre-monsoon Tmin. The KRC and MK tests yielded similar results in close resemblance with the SROC test. The performance of two modified MK tests considering variance-correction approaches was found superior to the KRC, MK, modified MK with pre-whitening, and ITA tests. The performance of original MK test is poor due to the presence of serial correlation, whereas the ITA method is over-sensitive in identifying trends. Significantly increasing trends are more prominent in Tmin than Tmax. Further, both the annual and monsoon rainfall time series have a significantly increasing trend of 9 mm year−1. The sequential significance of linear trend in MK test-statistics is very strong (R2 ≥ 0.90) in the annual and pre-monsoon Tmin (90% grid points), and strong (R2 ≥ 0.75) in monsoon Tmax (68% grid points), monsoon, post-monsoon, and winter Tmin (respectively 65, 55, and 48% grid points), as well as in the annual and monsoon rainfalls (respectively 68 and 61% grid points). Finally, this study recommends use of variance-corrected MK test for the precise identification of trends. It is emphasized that the rising Tmax may hamper crop growth due to enhanced metabolic-activities and shortened crop-duration. Likewise, increased Tmin may result in lesser crop and biomass yields owing to the increased respiration.
[en] The fishing industry of the China is the largest in world which is usually believed to be facing overexploitation risk. In this condition, it becomes necessary to estimate stock status of fishery resources particularly having commercial importance. Thus, this study is the first time attempt to know whether Spanish mackerel, a major landed fishery resource in Shandong, China, is experiencing overexploitation or not by estimating its stock status. For this purpose, long data series, 2006-2016, comprised of catch and effort figures was statistically analyzed to know maximum sustainable yield (MSY) of this resource and its ongoing regime. In total, three surplus production models (SPMs) were used in this study, viz., Fox (FM), Schaefer (SM) and Pella-Tomlinson (PTM) with the help of two famous fishery statistical routines, viz., catch and effort data analysis (CEDA) and a stock production model incorporating covariates (ASPIC). For initial proportion (IP) 1, CEDA estimated MSY in a range between 41000-50000 t, whereas, ASPIC calculations remained between 44000-52000 t. Furthermore, results also showed that fishing mortality (F) is increasing while biomass (B) is swiftly decreasing. Based on the results it can be concluded that Spanish mackerel is facing the risk of overexploitation. Thus, it is recommended to make such policies which can conserve this fishery resource for future. (author)
[en] As a renewable carbon resource, biomass can be converted into polyols, aromatic hydrocarbons, alkanes, and other products by traditional catalytic liquefaction method, which has been widely used in production and life. The efficient development and utilization of biomass energy will play a very positive role in solving the problems of energy and ecological environment. A way of combining the plasma electrolysis with traditional catalytic liquefaction realizes the efficient liquefaction of sawdust, which provides a new liquefaction way for traditional biomass conversion. In this experiment, the effects of solution composition, catalyst content and power supply on solution resistance and liquefaction rate are analyzed. It is found that solution composition and catalyst content have a great influence on solution resistance. The results show that the liquefaction rate is highest and the resistance is smallest when the solution resistance is 500 Ω. The liquefaction rate is greatly affected by the solution temperature, and the solution temperature is determined by the output power between the two electrodes. The output power includes the heating power of the electric field and the discharge power of the plasma. We measure the electric potential field distribution in the solution and the plasma power. It is found that the output power between the two poles increases nonlinearly (from 0 to 270 W) with time. In two minutes, the electric field heating power increases from 0 to 105 W and then decreases to 70 W, while the plasma power increases from 0 to 200 W. It is well known that in the first 70 seconds of the experiment the electric field heating is dominant, and then the plasma heating turns into a main thermal source. In this paper, plasma electrolysis and traditional catalytic liquefaction are combined to achieve the efficient liquefaction of sawdust, which provides a new way for biomass liquefaction. (paper)
[en] Solar water disinfection (SODIS) is a simple, effective, sustainable and low cost treatment that uses solar radiation as a biocide to improve the microbiological quality of drinking water. It is based on the exposure of water in polyethylene terephthalate (PET) bottles to the sunlight during at least 6 h (SODIS Foundation). Several factors influence the SODIS efficacy such as temperature, radiation intensity, turbidity, dissolved oxygen and salts, organic matter, material and shape of the container and the exposure time (Nelson et al., 2018). This method is one of the World Health Organization recommended treatments of drinking water at household level in developing countries. Cryptosporidium is a genus of emerging waterborne protozoan parasites, which infectious form (the oocyst) is highly resistant to common water disinfectants such as chlorine and ozone (Robertson 2015). For this reason, this parasite causes important outbreaks in developed countries and it is a significant endemic factor in developing countries, being responsible for approximately 202,000 deaths in children under the age of 2 (Sow et al., 2016). The objective of the present study was to evaluate the individual effects of temperature and radiation intensity in the inactivation of Cryptosporidium by SODIS method.
[en] Hierarchical structure composites of loofah derived biomass carbon (PBC) decorated by aligned polyaniline (PANI) were successfully fabricated by simple carbonization and in situ oxidative polymerization. The morphology and structural of composites was studied. The microwave absorbing performance of aligned PANI/PBC was investigated in the frequency range of 2–18 GHz. The results indicated that aligned PANI/PBC with special structure possessed more distinct dielectric response characteristics and enhanced microwave absorbing performance. The minimum reflection loss (RL) value of aligned PANI/PBC was up to − 44.8 dB at 10.02 GHz and the effective absorption frequency width (RL < − 10 dB) is in the 5.58–18 GHz range with the thickness range of 1–3 mm. The excellent microwave absorbing performance of aligned PANI/PBC was mainly correlate with the multiple relaxation polarization, good impedance matching and the synergistic effect between PANI nanorods and PBC.
[en] The goal of this paper is to identify, for the first time, the role of solar production in driving silver prices. The empirical analysis makes use of the ARDL model and the combined cointegration. The results, spanning the period 1990–2016, document that stronger solar installed capacities, as well as higher gross electricity production from solar sources, lead to higher silver prices. The findings could be of great importance to silver suppliers and to energy policymakers and regulators, as well as to solar panel manufacturers.
[en] Based on the ability of some specific aquatic plants to concentrate metals in their roots, we propose an innovative biosorption system to clean up mining effluents. The system we propose represents an interesting solution to an important environmental problem, the decontamination of metal-polluted water and prevention of dispersal of metals into the environment. The solution presented is a form of ecological recycling of Zn, an essential primary metal in many industrial applications. Finally, the methodology developed is a sustainable way of managing the biomass from eradication or control of invasive plants.