Research on a small-noise reduction method based on EMD and its application in pipeline leakage detection

The noise included in pipeline pressure signal is a small noise whose energy takes a small proportion of pressure signal and is concentrated on high frequency components. However, it will influence pipeline leakage identification and even cause false alarms. Thus, a small-noise reduction method based on EMD (SNR-EMD) is proposed to remove small noise from pressure signal. EMD is applied for extracting the mean envelope of the signal. Then, small fluctuations around the mean envelope are considered to be small noises. Meanwhile, end effect of SNR-EMD is restrained by extrema mirror extension (EME). The results of simulation studies with SNR-EMD show that the larger the noisy signal's signal-to-noise ratio (SNR) is, the better noise reduction effect becomes. And SNR-EMD considered as a low-pass filter removes or reduces the high frequency components. Furthermore, superiorities of SNR-EMD are verified by comparison studies with wavelet packet transform (WPT) and singular value decomposition (SVD). Finally, a case study of leakage identification shows that SNR-EMD can improve the performance of leakage identification and reduce the possibility of false alarms, which makes much easier and further effective to distinguish the leakage mode from other modes after removing noise from pressure signal.     

Achieving SDG 6: water resources sustainability in Caribbean Small Island Developing States through improved water governance

Scientific findings confirm that Small Island Developing States (SIDS) in the Caribbean are experiencing droughts and sea level rises that are contributing to saline intrusion of underground aquifers and surface water sources. This paper, using Trinidad as a case study, analyses water governance challenges in meeting Sustainable Development Goal (SDG) 6, which addresses the sustainability of water resources. Interviews were conducted with professionals from multi‐disciplinary backgrounds. Also, data provided by the water agency were analysed to evaluate water governance practices. The main contribution of this paper is the generation of a blend of policies, good practices and tools to confront growing threats to water security and to attain sustainable development in Caribbean SIDS in an era of climate change and increasing non‐climatic stressors. The paper concludes that economic, environmental and human resources, reformed administrative and legislative systems, and technological tools are fundamental to achieving good water governance. Moreover, an array of complementary policies and technologies is needed to resolve water governance issues. However, political will to implement sustainable water resources management is the greatest challenge in attaining SDG 6.     

China's small coal mine policy in the 2000s: A case study of trusteeship and consolidation

China has been trying to improve the safety and environmental performances of small coal mines (SCMs) in 2000s through measures of trusteeship and consolidation. The question whether such policy and practice can sustain small scale mining is interesting academically and important practically for China and the world. This paper finds that the Chinese SCM policy has been switched from encouragement to restriction for legal SCMs and from privatization to nationalization in some provinces in the past 10 years. Legal SCMs face pressure to be expanded continuously and to be absorbed or consolidated by large coal mines, which often are state owned. Unexpectedly, financial resources may not be a big constraint nowadays due to availability of private equity investment resources. The paper argues that both the trusteeship and consolidation approaches may only be able to sustain SCMs in the short run. A more sustainable measure is to establish a stable, transparent and inclusive legal and fiscal framework. This paper concludes that those trusteeship approaches may be applicable to restructuring small scale mines in other countries; however, the consolidation practice in China's is unique and thus may not be applicable to others.     

Gemstone mining as a development cluster: A study of Brazil’s emerald mines

For many centuries, emeralds have bejeweled the rich and famous all over the world. Emeralds have also made many millionaires overnight, sometimes by chance, as in some of the cases reported in this study. On the other hand, even though emerald mining has brought some economic benefits, many of these have remained at the top of the production chain. In many cases mining activities have caused a number of negative social and environmental impacts locally. Working conditions in small mines are very poor in general: with bad ventilation, high temperatures, long working hours, lack of safety, informal working contracts and no health or life insurance. Environmental impacts can be significant, such as widespread deforestation, erosion of abandoned mines, and soil and water pollution in streams. The economic and social public benefits can be minimal. Even when taxes on gem mining are relatively low, much of the mining local activity is informal and the high value-added formal activities take place outside the mining regions. This study aims to understand the dynamics of emerald mining and its impact on local development using the concept of clusters. The research analyzes three case studies in Brazil: Campos Verdes/Santa Terezinha (Goias state), Nova Era/Itabira (Minas Gerais state) and Carnaiba/Campo Formoso (Bahia state). Emerald mining regions attract many migrants, increasing the demand for public services (infrastructure, health, education, etc.), but local governments are unable to provide for them because the activity produces little tax revenue. In the end, there is a growing mismatch between demand and supply of public services, leading to a series of social and environmental problems. However, working with the concept of cluster can help to shed light on policies to improve the local benefits of gem mining, by organizing the miners and their supporting organizations to allow investments that bring long term benefits locally.     

中小锅炉烟道式旋流喷淋脱硫装置

本文通过对某市4t/h燃煤锅炉烟气除尘脱硫系统技术改造工程实例的介绍,结合干法除尘和湿法脱硫工艺流程,介绍了一种新型的烟道式脱硫装置及脱硫效果。     

JMarinas: A simple tool for the environmentally sound management of small marinas

A novel index for the preliminary evaluation of the distribution of pollutants in the harbor environment (Small Marinas Pollution Risk) is proposed. An associated Environmental Decision Support System (JMarinas) has been developed which implements the Multiple Attribute Decision Making theory (MADM) and uses the harbor’s map as geographical support for computations. The MADM matrix is built considering various attributes of the marina and is calculated using both qualitative and quantitative data.     

Qualitative modeling and monitoring of selected ecosystem functions

This paper proposes three qualitative models that were applied for modeling of Small Water Cycle violation in ecosystem of Trebon region, South Bohemia. SWC refers to the behavior of the local ecosystem (e.g., the Trebon region), in which the volume of water that comes into the ecosystem is evaporated and falls back into this system. SWC is characterized by early morning dues and frequent small rain precipitation. In the Trebon Biosphere Reserve characterized by wetlands, forests and agriculture land, the evaporated water rises quickly inside the zone and does not have time to recondense before it is transported outside the ecosystem to the distant mountains, where it condenses spontaneously in the rising air streams.The essential pre-model for developing our qualitative models is the database model implemented in the MS SQL environment. The data in this model were collected for last five years and contain information about SWC violation and about the landscape stability development. The database system is used for standard reports, for correlating digital and graphic runs from associated meteorological stations, and for computing the evapotranspiration at the points where the stations are located and also at approximate inter-points.In parallel, and in addition to this standard use of the database model, the data was applied in the development of qualitative models (state model, model for the detection of unexpected situations and matroid model). This transformation and compression of the data was done with help of experienced experts and with the help of special mathematical operations. Qualitative models introduced in this paper overcome experience with quantitative models namely in these items: (1) They provide compression of information contained in large volumes of numerical data. (2) On the contrary of individual quantitative modeling qualitative models enable to describe the function and properties of the whole ecosystem. (3) Conclusions from qualitative models are in many cases better than are the generalizations of results from quantitative models.The first goal of the paper is to model situations associated with violations of the Small Water Cycle (SWC) in this ecosystem, and to contribute to acceptable solutions. The second goal of the paper is to investigate temporary models for the stability of the landscape development and to propose qualitative models for software support for integrated environmental modeling.     

Residual levels and health risk of polycyclic aromatic hydrocarbons in freshwater fishes from Lake Small Bai-Yang-Dian, Northern China

The residual levels of polycyclic aromatic hydrocarbons (PAHs) in the liver, brain, gill and muscle tissues of four common edible freshwater fish species including crucian carp, snakehead fish, grass carp and silver carp collected from Lake Small Bai-Yang-Dian in northern China were measured by GC-MS. The distribution and composition pattern of PAHs in the fish tissues, and the effects of lipid contents in fish tissues and the octanol-water partition coefficient (Kow) of PAHs congeners on them were analyzed. The human health risk of PAHs though fish consumptions was estimated. The following results were obtained: (1) The average residual levels of total PAHs (PAH₁₆) on wet weight base in the different tissues of each fish species ranged from 4.764 to 144.254 ng/g ww. The differences in the average residual levels on wet weight base for PAH₁₆ within four fish species were not statistically significant (P > 0.05); however, these within four fish tissues were statistically significant (P < 0.01). (2) There were very similar distribution patterns of PAH congeners among both the fish tissues and the fish species, as indicated by statistically significant positive interrelationships (R = 0.58-0.97, P < 0.01 or P < 0.05). Low molecular weight (LMW) PAHs predominated the distribution in the fish tissues, accounting for 89.97% of total PAHs. Phe was the most dominant component, according for 37.79% of total PAHs, followed by Ant (18.59%), Flo (12.59%), Nap (10.79%), Fla (9.82%) and Pyr (6.43%). (3) The PAHs residues and distribution in the fish tissues are dependent on both the Kow of PAH congeners and the lipid contents in the fish tissues. There was a significant positive relationship (R = 0.7116, P < 0.0001) between lipid contents and PAHs residual levels. The statistically significant negative relationships (P < 0.05) were found between LogKow and log-transformed PAHs contents on wet weight base for all fish tissues except for the muscle tissue of snakehead fish, the brain and liver tissues of crucian carp. (4) The risk levels of total PAHs were lower than 10⁻⁵ for the muscle tissues of four studied fish species and for the brain tissues of grass carp and snakehead fish; while these were higher than 10⁻⁵ for the brain tissues of crucian carp and silver carp. The risk levels of total PAHs in the liver tissues of four studied fish species except for snakehead fish exceeded 10⁻⁵ for 2-4.5 times. However, the potency equivalent concentration (PEC) of total PAHs in four studied fish tissues were still lower than the maximum permissible BaP limits for crops and baked meat and for plants in the national criterions. The distributions of PAH congeners in fish were well simulated by a level III fugacity model, especially for low molecule weight PAHs.     

Activity of root voles (Microtus oeconomus) under snow: social encounters synchronize individual activity rhythms

Microtine rodents usually display short-term activity rhythms synchronized by light. Social interactions have also been suggested to act as a zeitgeber, entraining individual activity, but evidence supporting this is scarce. In areas with a permanent snow cover during winter, small rodents spend most of the time in the subnivean space, between the snow cover and the ground, where they most likely are unaffected by otherwise dominating photoperiodic cues. The subnivean space, however, is fragmented, and this limits movement and may isolate individuals living just a few meters apart. These conditions provide excellent opportunities to test for the existence of social synchronization. During two winters, I experimentally decreased the subnivean fragmentation by placing out a network of corrugated aluminium sheets on the ground before snowfall, thus increasing the potential for movement and social interaction within the subnivean space. Other areas were left as controls. Intensive PIT-tag monitoring in the subnivean system provided individual activity data of root voles (Microtus oeconomus) without disturbing normal activity. The data revealed that microtines under snow displayed a free-running activity rhythm and that the activity was evenly distributed throughout the 24-h day, indicating a lack of photo-entrainment. Despite this lack of light, interacting individuals were synchronous, and pairwise synchrony decreased with decreasing potential for social interactions. These results suggest that social interactions indeed entrain microtine activity. Several possible adaptive advantages of the synchrony of microtine rodent activity have been proposed, and these theories are discussed in light of the result presented.