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Environments, Volume 5, Issue 7 (July 2018)

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Cover Story (view full-size image) Environmental factors, such as light, could influence interactions between trace metals and [...] Read more.
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Open AccessArticle Characterization of Recycled Wood Chips, Syngas Yield, and Tar Formation in an Industrial Updraft Gasifier
Environments 2018, 5(7), 84; https://doi.org/10.3390/environments5070084
Received: 15 June 2018 / Revised: 16 July 2018 / Accepted: 20 July 2018 / Published: 22 July 2018
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Abstract
In this study, the moisture content, calorific value, and particle size of recycled wood chips were measured. The wood chips were used to fuel an 8.5 MWth updraft gasifier to produce syngas for combustion in a steam-producing boiler. In-situ syngas composition and
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In this study, the moisture content, calorific value, and particle size of recycled wood chips were measured. The wood chips were used to fuel an 8.5 MWth updraft gasifier to produce syngas for combustion in a steam-producing boiler. In-situ syngas composition and tar concentrations were measured and analyzed against biomass fuel properties. No efforts were made to adjust the properties of biomass or the routine operating conditions for the gasifier. A sampling device developed by CanmetENERGY-Ottawa (Ottawa, ON, Canada) was used to obtain syngas and tar samples. Wood chip samples fed to the gasifier were taken at the same time the gas was sampled. Results indicate that as the fuel moisture content increases from 20% to 35%, the production of CO drops along with a slight decrease in concentrations of H2 and CH4. Tar concentration increased slightly with increased moisture content and proportion of small fuel particles (3.15–6.3 mm). Based on the findings of this study, biomass fuel moisture content of 20% and particles larger than 6.3 mm (1/4″) are recommended for the industrial updraft gasifier in order to achieve a higher syngas quality and a lower tar concentration. Full article
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Open AccessArticle Pronounced Antagonism of Zinc and Arsenate on Toxicity to Barley Root Elongation in Soil
Environments 2018, 5(7), 83; https://doi.org/10.3390/environments5070083
Received: 17 May 2018 / Revised: 6 July 2018 / Accepted: 13 July 2018 / Published: 17 July 2018
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Abstract
Zinc (Zn) and arsenic (As) occur as mixed contaminants in soil and the interactions between them remain unclear. Here, we investigated a Zn2+ and H2AsO4 mixture interaction and their effects on plant growth. Three different soils were spiked
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Zinc (Zn) and arsenic (As) occur as mixed contaminants in soil and the interactions between them remain unclear. Here, we investigated a Zn2+ and H2AsO4 mixture interaction and their effects on plant growth. Three different soils were spiked with ZnCl2 and NaH2AsO4, each dosed singly or in combination. The soils were leached to remove excessive salt and were aged (>7 days), before toxicity testing using a 5-day root elongation of barley (Hordeum vulgare L.). In the single treatments, the 50% inhibitory effect concentrations in the soil (EC50, total measured concentration) were 2000–3800 mg Zn kg−1 and 96–620 mg As kg−1, depending on the soils. The mixture analyses based on the total concentrations showed overall and significant Zn–As antagonism in two soils, either based on the concentration addition (CA) or independent action (IA) model, whereas no significant interactions (either CA or IA) were found in one soil, which had the lowest content of Fe-oxides. The soil solution composition showed a decreased As concentration upon the addition of ZnCl2 at an equal soil As total concentration; however, the reverse was not found, in line with the cation–anion electrostatic interaction or formation of ternary surface complexes on Fe-oxides. The data revealed that the Zn–As antagonisms (total concentrations) are partially related to the increased Zn immobilizing As in soil. Full article
(This article belongs to the Special Issue Environmental Toxicology of Trace Metals)
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Open AccessArticle Oxidative Destruction of Organic Pollutants on the Polypropylene Fiber Modified by Nanodispersed Iron
Environments 2018, 5(7), 82; https://doi.org/10.3390/environments5070082
Received: 4 June 2018 / Revised: 9 July 2018 / Accepted: 11 July 2018 / Published: 16 July 2018
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Abstract
This study aims to solve the problem of deep destruction of organic pollutants in industrial effluents by creating new composite materials with prescribed functional properties. This paper researches the possibility of using composites based on a polypropylene fiber under conditions of photocatalytic degradation
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This study aims to solve the problem of deep destruction of organic pollutants in industrial effluents by creating new composite materials with prescribed functional properties. This paper researches the possibility of using composites based on a polypropylene fiber under conditions of photocatalytic degradation of organic pollutants in aqueous and aqueous-organic media. Dye that are water soluble (eosin, brilliant green, rhodamine C) and fat-soluble (blue, yellow and red) have been chosen as organic contaminants. Composites based on the polypropylene fiber have been obtained by introducing nanodispersed iron onto the surface of the initial polymer, using ion implantation and super high frequency irradiation methods. The obtained composites are characterized, and their photocatalytic activity is studied with respect to the pollutants under study in the conditions of the Fenton-like system and visible radiation. The results show that the obtained composite materials are effective catalysts for oxidative photodestruction of organic dyes in aqueous and aqueous-organic media, and their decolorization degree reaches 80–100%. Full article
(This article belongs to the Special Issue Advanced Oxidation Applications)
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Open AccessReview Combined Effects of Trace Metals and Light on Photosynthetic Microorganisms in Aquatic Environment
Environments 2018, 5(7), 81; https://doi.org/10.3390/environments5070081
Received: 14 June 2018 / Revised: 6 July 2018 / Accepted: 8 July 2018 / Published: 12 July 2018
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Abstract
In the present review, we critically examine the state-of-the-art of the research on combined effects of trace metals and light on photosynthetic microorganisms in aquatic environment. Light of different intensity and spectral composition affects the interactions between trace metals and photosynthetic microorganisms directly,
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In the present review, we critically examine the state-of-the-art of the research on combined effects of trace metals and light on photosynthetic microorganisms in aquatic environment. Light of different intensity and spectral composition affects the interactions between trace metals and photosynthetic microorganisms directly, by affecting vital cellular functions and metal toxicokinetics and toxicodynamics, and indirectly, by changing ambient medium characteristics. Light radiation and in particular, the ultraviolet radiation component (UVR) alters the structure and reactivity of dissolved organic matter in natural water, which in most of the cases decreases its metal binding capacity and enhances metal bioavailability. The increase of cellular metal concentrations is generally associated with increasing light intensity, however further studies are necessary to better understand the underlying mechanisms. Studies on the combined exposures of photosynthetic microorganisms to metals and UVR reveal antagonistic, additive or synergistic interactions depending on light intensity, spectral composition or light pre-exposure history. Among the light spectrum components, most of the research was performed with UVR, while the knowledge on the role of high-intensity visible light and environmentally relevant solar light radiation is still limited. The extent of combined effects also depends on the exposure sequence and duration, as well as the species-specific sensitivity of the tested microorganisms and the activation of stress defense responses. Full article
(This article belongs to the Special Issue Environmental Toxicology of Trace Metals)
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Open AccessArticle Empirical Study of the Quantization Induced Bias in Commercial Microwave Links’ Min/Max Attenuation Measurements for Rain Monitoring
Environments 2018, 5(7), 80; https://doi.org/10.3390/environments5070080
Received: 24 May 2018 / Revised: 1 July 2018 / Accepted: 9 July 2018 / Published: 11 July 2018
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Abstract
Commercial microwave links have a great potential to be used as sensors for rain. However, the use of commercial microwave links to monitor the rain depends heavily on the availability of the links’ attenuation measurements. The cellular operators which provide the majority of
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Commercial microwave links have a great potential to be used as sensors for rain. However, the use of commercial microwave links to monitor the rain depends heavily on the availability of the links’ attenuation measurements. The cellular operators which provide the majority of these measurements usually make use of the standard Network Management Systems (NMS), which log only a quantized version of the minimum and the maximum attenuation values (usually in 15-min intervals). The non-linear min/max transformation, in combination with the quantizer, which are implemented on the channel attenuation measurements, should be considered during the rain-estimation procedures. In this paper, we examine actual NMS produced attenuation measurements that are taken from two commercial microwave links during multiple rain events. Using observations from two rain gauges and a weather radar, we empirically demonstrate that the output of the NMS includes bias, which in turn interferes with the rain-estimation process. We show that the detection and the compensation of this bias have the potential to increase the microwave links’ rain-estimation accuracy considerably. Full article
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Open AccessArticle Fuel Treatments and Potential Fire Behavior in Peri-Urban Forests in Northern Greece
Environments 2018, 5(7), 79; https://doi.org/10.3390/environments5070079
Received: 6 June 2018 / Revised: 6 July 2018 / Accepted: 9 July 2018 / Published: 10 July 2018
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Abstract
The peri-urban and urban forests in Greece occupy a total area of 105.353 ha. In these vulnerable ecosystems, fire constitutes a natural disaster presenting particular challenges and specific difficulties. These include the high number of visitors as well as the forest characteristics, such
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The peri-urban and urban forests in Greece occupy a total area of 105.353 ha. In these vulnerable ecosystems, fire constitutes a natural disaster presenting particular challenges and specific difficulties. These include the high number of visitors as well as the forest characteristics, such as the presence of particularly flammable tree species and the high accumulation of combustible biomass, that make the on-start of fires more likely. The main purpose of the current research is to identify the optimum combination of silvicultural treatments to efficiently reduce potential severity of forest fires and to facilitate their successful suppression by firefighting crews. In order to simulate the basic fire environment of urban forests, two main experimental plots were established and several tree and topographical characteristics were measured. Additionally, a crown fire hazard modelling system (NEXUS) was used to simulate forest fire potential behavior before and after the adoption of the silvicultural treatments that altered critical characteristics of the forest fire environment. The results clearly show that specific silvicultural prescriptions altered the type of forest fire spreading potential, revealing the overall efficiency of preventing actions during forest management. Full article
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Open AccessArticle Seasonal Variation and Retention of Ammonium in Small Agricultural Streams in Central Thailand
Environments 2018, 5(7), 78; https://doi.org/10.3390/environments5070078
Received: 1 June 2018 / Revised: 28 June 2018 / Accepted: 3 July 2018 / Published: 5 July 2018
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Abstract
Elevated nutrient concentrations are of concern in many agricultural streams. This study observed seasonal variation of inorganic nitrogen concentrations in small drainage streams that receive discharge predominantly from three different types of agricultural practices, swine farms, aquaculture, and paddy fields, in the Tha
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Elevated nutrient concentrations are of concern in many agricultural streams. This study observed seasonal variation of inorganic nitrogen concentrations in small drainage streams that receive discharge predominantly from three different types of agricultural practices, swine farms, aquaculture, and paddy fields, in the Tha Chin River Basin in central Thailand. The drainage streams had high inorganic nitrogen concentrations, low dissolved oxygen concentrations (<3 mg L−1), and ammonium was the dominant form of inorganic nitrogen. The highest ammonium concentrations were observed in the drainage streams through swine farm areas, exceeding 4 mg L−1 throughout the year. In-stream ammonium retention was examined using pulse co-injections of ammonium and chloride in a drainage stream, and the effects of in-channel vegetation on ammonium retention were evaluated. This study showed that a considerable amount of ammonium was retained with the presence of in-channel vegetation. After vegetation removal, both the hydraulic and ammonium uptake length increased by >50 m, and the ammonium retention declined by approximately 50%. These results suggest that small agricultural streams experience a high concentration of inorganic nitrogen, similar or even more than larger streams, and that in-channel vegetation plays important role in nitrogen retention. The management of in-channel vegetation will have considerable effects on nitrogen transport. Full article
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Open AccessArticle Application of GIS-Based Multi-Criteria Decision Technique in Exploration of Suitable Site Options for Anaerobic Digestion of Food and Biodegradable Waste in Oita City, Japan
Environments 2018, 5(7), 77; https://doi.org/10.3390/environments5070077
Received: 30 May 2018 / Revised: 29 June 2018 / Accepted: 2 July 2018 / Published: 4 July 2018
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Abstract
Recently, the popularity of anaerobic digestion (AD) has been increasing, and selecting a site for AD is a complex process for both individuals and decision-makers. This process requires the selected site to fulfill all regulation requirements, simultaneously reducing environmental, sociocultural, technical, political, economic,
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Recently, the popularity of anaerobic digestion (AD) has been increasing, and selecting a site for AD is a complex process for both individuals and decision-makers. This process requires the selected site to fulfill all regulation requirements, simultaneously reducing environmental, sociocultural, technical, political, economic, and public health costs. A geographic-information-system-based multi-criteria decision analysis (GIS-MCDA) is presented in this study to evaluate and examine the suitability of the study area in order to propose a suitable site for an AD facility in Oita City, Japan. Multi-criteria evaluation (MCE) was used to standardize the map layers into fuzzy membership functions. The proximity variables were classified into seven factors and three constraint groups, specifically, environmental, sociocultural, and technical/economic criteria. The proximity and criteria maps were combined using weighted linear combination (WLC) techniques, and the resulting suitability map was evaluated on a grading scale of 0–255 B. The analytical hierarchy process (AHP) ranking analysis indicated that an area of about 13.36 km2 from the entire study area is the most suitable and that the remaining two options are still suitable for the intended purpose, but the entire decision will be entrusted to the decision-makers’ judgment. Full article
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Open AccessArticle Assessing the Potential for Small-Scale Aquaculture in Cambodia
Environments 2018, 5(7), 76; https://doi.org/10.3390/environments5070076
Received: 28 May 2018 / Revised: 24 June 2018 / Accepted: 26 June 2018 / Published: 29 June 2018
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Abstract
Fisheries in Cambodia play an important role in supporting household food security and livelihoods throughout the country. Inland fisheries production is largely dependent on numerous ecosystem services, particularly the floodwaters of the Tonle Sap Lake basin, which has been degraded from increased fishing
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Fisheries in Cambodia play an important role in supporting household food security and livelihoods throughout the country. Inland fisheries production is largely dependent on numerous ecosystem services, particularly the floodwaters of the Tonle Sap Lake basin, which has been degraded from increased fishing pressure because of population growth and a rising demand for fish. To address the dual problem of food insecurity and overfishing, an integrated food security and climate change program involved the promotion of small-scale aquaculture through semi-intensive pond management. The objective of this study is to examine perceptions of small-scale aquaculture by participants in this program in order to assess the potential for aquaculture to contribute to household food security and conservation of the Tonle Sap Lake ecosystem. Focus group discussions and a household survey were conducted among current and previous fish farmers. Results demonstrate that most farmers continue to practice small-scale aquaculture as a means to supplement household food availability and income. Numerous barriers to adoption of small-scale aquaculture were identified, including access to water, prices of commercial fish feed, selling price of fish in markets and concerns about profitability. Seasonal water scarcity is the most prominent challenge in promoting aquaculture technologies, so aquaculture development should be expanded in areas where there are abundant supplies of water, or where use of water storage techniques is feasible. Aquaculture technology appears to have the potential to contribute to food security, nutrition and household income and to the conservation of the wild fisheries of the Tonle Sap Lake. Full article
(This article belongs to the Special Issue Agricultural Ecosystem Services)
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Open AccessArticle Advancements in the Statistical Study, Modeling, and Simulation of Microwave-Links in Cellular Backhaul Networks
Environments 2018, 5(7), 75; https://doi.org/10.3390/environments5070075
Received: 3 June 2018 / Revised: 25 June 2018 / Accepted: 26 June 2018 / Published: 28 June 2018
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Abstract
While the effect of rainfall and other environmental phenomena on a link budget in microwave wireless communication has been well studied for network design, it has usually been done for each microwave-link separately. Recently, attenuation in multiple microwave-links is being used simultaneously for
[...] Read more.
While the effect of rainfall and other environmental phenomena on a link budget in microwave wireless communication has been well studied for network design, it has usually been done for each microwave-link separately. Recently, attenuation in multiple microwave-links is being used simultaneously for rainfall mapping over specific areas, and consequently, rain-induced attenuation fields can be constructed. Dedicated algorithms have been designed to relate attenuation in multiple microwave-links to its corresponding rain-field. Their performance depends significantly on the structure of the network. As the topology of a cellular microwave network (CMNs) is region-dependent, general theory for its effect on performance can only be developed statistically. In this paper we study the statistical nature of CMNs and lay the groundwork for such models based on empirical results. Full article
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Open AccessArticle Vertical Precipitation Estimation Using Microwave Links in Conjunction with Weather Radar
Environments 2018, 5(7), 74; https://doi.org/10.3390/environments5070074
Received: 29 May 2018 / Revised: 19 June 2018 / Accepted: 20 June 2018 / Published: 23 June 2018
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Abstract
When monitoring rain rates by weather radar in semi-arid regions and when measuring precipitation at an arid region; precipitation particles, rain, or snowflakes may evaporate before reaching the ground. This evaporation is regarded as the Virga phenomenon and may cause a false representation
[...] Read more.
When monitoring rain rates by weather radar in semi-arid regions and when measuring precipitation at an arid region; precipitation particles, rain, or snowflakes may evaporate before reaching the ground. This evaporation is regarded as the Virga phenomenon and may cause a false representation of the precipitation amount that actually reaches the ground. The Virga occurs naturally when the air below the cloud is relatively dry, and continues until humidity below the base of the cloud is high enough to decrease the evaporation. This paper suggests a method of combining near ground Commercial Microwave Links (CMLs) attenuation measurements, in conjunction with data from several weather radar beams, observing different heights, in order to produce estimates of the vertical profile of the rain-rate values and of the Cloud Base level (ClB). We propose an estimation method and demonstrate it using real-data measurements of two major storm events in the dead-sea area. We verify the validity of the estimation near ground by comparing the results with Rain Gauges’ (RGs) actual measurements in addition to comparing the estimated ClB with real ClB observations of a nearby weather station. While the storm events selected indeed show great evaporation, the suggested method provides excellent results, with a correlation of up to 0.9615, when correlated with real measurements of RGs of two storms from 2014 to 2016. Full article
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Open AccessArticle Capitalizing on Cellular Technology—Opportunities and Challenges for Near Ground Weather Monitoring
Environments 2018, 5(7), 73; https://doi.org/10.3390/environments5070073
Received: 8 May 2018 / Revised: 15 June 2018 / Accepted: 19 June 2018 / Published: 22 June 2018
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Abstract
The use of existing measurements from a commercial wireless communication system as virtual sensors for environmental monitoring has recently gained increasing attention. In particular, measurements of the signal level of commercial microwave links (CMLs) used in the backhaul communication network of cellular systems
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The use of existing measurements from a commercial wireless communication system as virtual sensors for environmental monitoring has recently gained increasing attention. In particular, measurements of the signal level of commercial microwave links (CMLs) used in the backhaul communication network of cellular systems are considered as opportunistic sensors for precipitation monitoring. Research results have demonstrated the feasibility of the suggested technique for the estimating and mapping of rain, as well as for monitoring other-than-rain phenomena. However, further advancement toward implementation and commercial use are heavily dependent on multidisciplinary collaborations: Communication and network engineers are needed to enable access to the existing measurements; signal processing experts can utilize the different data for improving the accuracy and the tempo-spatial resolution of the estimates; atmospheric scientists are responsible for the physical modeling; hydrologists, meteorologists, and others can contribute to the end uses; economists can indicate the potential benefits; etc. In this paper I will review state-of-the-art results and the open challenges, demonstrating the benefit to the public good from utilizing the opportunistic-sensing approach. I will also analyze the various obstacles on the way there. Full article
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