Stream Types Research Articles

Effects of intermittent flow on biofilms are driven by stream characteristics rather than history of intermittency

Intermittent streams are found all over the world, however most studies focus on intermittency in hot, arid climates. As flow intermittency is expected to increase with climate change, it is important to understand how stream biofilms in temperate regions respond to these changing conditions. In this study, 20 different streams from around Austria were sampled under flowing and non-flowing conditions to evaluate the effect of intermittency on temperate stream biofilms. These streams encompassed two distinct stream types: fine-grained with high agricultural land use and coarse sediments from relatively pristine areas. Half of these streams were historically intermittent and half historically perennial. Samples were taken from all streams during the spring and fall, when the intermittent streams were flowing and dry, respectively. Subsets of the sediments were subjected to controlled drying to evaluate the effects of history of intermittency on the biofilms. Samples were analyzed for respiration, extracellular enzyme activities, and extracellular polysaccharides in the wet and dry sediments from the field, as well as the lab-dried sediments. This study found that lab-dried perennial sediments showed similar responses to the intermittent sediments, indicating that history of intermittency does not affect biofilm response to drought. This study also found that the effects of grain size, seasonal growth, and nutrient levels have a larger impact on the biofilms than moisture content and history of intermittency.

Analysis of Roadway Grade Estimations From Global Positioning Systems and Barometer Measurements

Roadway grade is used as an input variable for several highway analysis tasks, including evaluating curve margin-of-safety, applying safety prediction models, assessing the adequacy of sight distance, and maintaining state roadlog databases. However, collecting accurate grade data is often expensive owing to the need to obtain field measurements or review as-built plan sets. Agencies would benefit from the development of a method to compute roadway grade from an automated data collection system. This paper documents a comparison of roadway grade estimations computed from global positioning system (GPS) and barometric altimeter data streams obtained during test drives on highway segments of interest. To calibrate the estimation method, the authors obtained ground-truth grade measurements collected from the field and then modeled those measures as responses in a time series model with the two data stream types as explanatory variables. The authors found that for several applications, the elevation data obtained from GPS were adequate to obtain reasonable estimates, but such estimations could be improved with a supplemental data stream from a barometer.

First steps in the ecological flow determining for Latvian rivers

Abstract This study analyses the impact of small hydropower plants (HPP) on fish in three Latvian transboundary river basin districts. The MesoHABSIM habitat simulation model was applied to seven Latvian lowland rivers regulated by HPP, four of which belong to the salmonid river type and three to the cyprinid type. Daily stream flow time series for 1961–2018 were used for flow regime calculations in reference (unimpacted) and altered (impacted by HPP operation) flow conditions. Conditional habitat suitability model/criteria for fish were used to assess a potentially available habitat at different flow conditions. Brown trout (Salmo trutta) for salmonid rivers and chub (Squalius cephalus) for cyprinid rivers were selected as case examples to show habitat suitability for different stream types. The authors found significant differences in habitat availability for salmonid and cyprinid rivers, indicating that ecological flows must be calculated separately for fast- and slow-flowing rivers. This study is the first attempt in Latvia to set ecological flow values not only using hydrological calculations but also biological data as an indicator of ecological changes.

A new carbon nanotube modified by nano CaO2 for removal of chromate and phosphate from aqueous solutions

Chromate and phosphate simultaneously exist in several types of waste streams (e.g., leather tannery). Herein, we developed a new carbon nanotube (CNT) modified by the nano calcium peroxide particles in-situ formed for the treatment. The CNTs with different ratios were prepared and tested for the performance. The CNT (CNT-3) prepared by 0.5-M CaCl2 and 0.5-M H2O2 demonstrated the best performance. It had a total -O-O- group content of 5.24 ± 0.68 mmol/g, and was uniformly covered by synthesized particles with an average diameter of 20–50 nm. At a dosage of 200 mg/L, the removal efficiency of Cr(VI) and phosphate was achieved with the percentage of 81 and 99%, respectively, at a contact time of 120 min. The maximum phosphate adsorption capacity was 126.74 mg-P/g, much higher than that of many adsorbents such as the reported Ca-based, Zr-based and La-based adsorbents. Commonly existing anions (namely SO42-, CO32–, SiO32-, NO3–, and Cl-) showed negligible effects on the simultaneous removal of oxyanions. However, the presence of arsenite greatly decreased the treatment efficiencies for both oxyanions; that of fluoride had no effect on the reduction of Cr(VI), but decreased the adsorption of phosphate. Acidic condition (e.g., pH 3.0) was beneficial for the Cr(VI) removal, but caused the negative effect on the phosphate removal. The chemical and physical properties of CNT-3 were studied via several analytical approaches (e.g., BET, Zeta potential, FESEM-EDX, XRD and XPS). Cr(VI) was removed via chemical reduction to Cr(III) by H2O2 released from CaO2 on CNT-3; phosphate was adsorbed via chemical precipitation (forming hydroxyapatite (Ca10(PO4)6(OH)2)) due to the presence of calcium ion and electrostatic interaction. This research indicates CNT-3 has a great potential for treatment of wastewater containing chromate and/or phosphate oxyanions.

Synergistic action of laccase treatment and membrane filtration during removal of azo dyes in an enzymatic membrane reactor upgraded with electrospun fibers

Nowadays, the increasing amounts of dyes present in wastewaters and even water bodies is an emerging global problem. In this work we decided to fabricate new biosystems made of nanofiltration or ultrafiltration membranes combined with laccase entrapped between polystyrene electrospun fibers and apply them for decolorization of aqueous solutions of three azo dyes, C.I. Acid Yellow 23 (AY23), C.I. Direct Blue 71 (DB71) and C.I. Reactive Black 5 (RB5). Besides effective decolorization of the permeate stream, the biosystems also allowed removal of dyes from the retentate stream as a result of enzymatic action. The effect of pH and applied pressure on decolorization efficiencies was investigated, and pH 5 and pressure of 2 bar gave the highest removal efficiencies of 97% for AY23 and 100% for both DB71 and RB5 from permeate solutions while decolorization of retentate for RB5 reached 65% under these conditions. Almost 100% decolorization of all dyes was achieved after three consecutive enzyme membrane cycles. Decolorization was shown to be due to the synergistic action of membrane separation and bioconversion. The biocatalytic action also enabled significant reduction of permeate and retentate toxicity, which is one of the biggest environmental health issues for these types of streams.

Toward a New Type of Stream for Interactive Content

We describe a method of game streaming, the Geometry Pump Engine Group protocol, designed to address the limitations of video-based cloud gaming and command streaming approaches. It produces a true content stream of subassets with adaptive scalability and intelligent caching.

Environmental literacy affects riparian clean production near major waterways and tributaries

Although environmental illiteracy threatens the functioning of landscapes throughout the world, it is frequently ignored. The traditional wisdom assumes that suspicions will evaporate when the public and government authorities are provided with new information. Despite significant efforts to enhance riparian corridor output, limited data are available on the effect of environmental literacy metrics (ELMs) on clean production elements (CPEs) across various streams (e.g., main rivers and tributaries) within impoundments. This study examined such effects within the China Three Gorges Dam Reservoir area (TGDRA) by collecting 336 transects that assessed the breadth of effects on 58,000 km2 in 2019. The network visualization revealed 7234 papers published over the last 121 years, each of which focused on themes such as plant cover, regeneration, exotics, erosion, habitat, and stressors. The bar graph showed that the general public lacked understanding of environmental literacy (e.g., knowledge, attitudes, and behavior), which influenced plant cover elements most in tributary zones but had little direct effect on regeneration. Locals' environmental literacy had the greatest impact on CPEs, with Pearson correlation coefficients ranging from −0.69 <r < 0.96 in the main river zones. Moreover, public employees' environmental literacy had a stronger correlation with CPEs (−0.58 <r < 0.83) within the main river regions. Farming systems, exposed soil, dominant grass regeneration, and instream structures, including pollution, were among the most notable CPEs within the TGDRA. According to hierarchical approaches, CPEs and ELMs change substantially across stream types. CPEs and ELMs vary significantly around main rivers and tributaries, requiring efforts to raise the public understanding of the worldwide impacts of stream health on humans.

Assessing China’s potential for reducing primary copper demand and associated environmental impacts in the context of energy transition and “Zero waste” policies

To conserve resources and enhance the environmental performance, China has launched the “Zero waste” concept, focused on reutilization of solid waste and recovery of materials, including copper. Although several studies have assessed the copper demand and recycling, there is a lack of understanding on how different waste management options would potentially reduce primary copper demand and associated environmental impacts in China in the context of energy transition. This study addresses this gap in view of a transition to low-carbon energy system and the optimization of copper waste management combining MFA and LCA approaches. Six types of waste streams (C&DW, ELV, WEEE, IEW, MSW, ICW) are investigated in relation to various “Zero waste” strategies including reduction, reuse (repair, remanufacturing or refurbishment), recycling and transition from informal to formal waste management. Under present Chinese policies, reuse and recycling of copper containing products will lead to a somewhat lower dependency on primary copper in 2100 (11187Gg), as well as lower total GHG emissions (64869 Gg CO2-eq.) and cumulative energy demand (1.18x10^12 MJ). Maximizing such “Zero waste” options may lead to a further reduction, resulting in 65% potential reduction of primary copper demand, around 55% potential reduction of total GHG emissions and total cumulative energy demand in 2100. Several policy actions are proposed to provide insights into future waste management in China as well as some of the challenges involved.

Alpha and beta diversity and species co‐occurrence patterns in headwaters supporting rare intermittent‐stream specialists

Abstract Intermittent rivers are the focus of a burgeoning subdiscipline of freshwater science, driven by mounting recognition of their ubiquity, biodiversity, and climate sensitivity. However, our understanding of their ecology is hampered by a reliance on unstandardised diversity measures, an underrepresentation of certain stream types in metacommunity research and a reticence to acknowledge biotic interactions as a potentially fundamental driver of catchment‐scale patterns in assemblage composition. This study analysed both local‐ and catchment‐scale responses of invertebrates to flow intermittence and hydrological isolation in an understudied ecosystem type (low‐gradient, groundwater‐fed headwaters). We compared responses of conventional (taxonomic richness, Shannon diversity) and more robust (coverage‐adjusted Hill–Shannon) α‐diversity metrics to drying, and analysed changes in β‐diversity components as a function of hydrological and spatial distances between samples. We also inferred the influence of biotic interactions on metacommunity structure, using hierarchical species distribution modelling to capture species‐to‐species associations after accounting for hydrological variability and dispersal traits. The conventional and robust α‐diversity metrics exhibited broadly similar shifts, although richness overestimated the decline in α‐diversity with intermittence and the Shannon index failed to detect a significant interaction between flow duration and hydrological isolation. Decomposition of β‐diversity revealed a dominance of species turnover over nestedness along the flow gradient, a finding contrary to prevailing conceptual wisdom in intermittent river ecology and one we attribute to the climatic and geological context of our study. Even after accounting for differences in hydrological niche occupation, we discovered a significant propensity for species to co‐occur with others of similar conservation status, implying that competition/colonisation trade‐offs involving rare specialists and widespread generalists could underpin metacommunity assembly in some drying headwater networks. Our results suggest that enhancing aquatic habitat connectivity in headwaters harbouring intermittent‐stream specialists could be counterproductive, and conservation plans should instead look to safeguard isolated habitats serving as biotic refuges for rare species.

Hydrochemical Composition Characteristics and Control Factors of Xiaohuangni River Basin in the Upper Pearl River

In order to serve the water resources management of the Xiaohuangni River basin, this study explored the hydrochemical composition characteristics and ion sources of surface water in the basin. Samples of main stream and tributary river water and mine water were systematically collected. By means of a Piper diagram, Gibbs diagram, ion ratio coefficient, and mathematical statistical analysis, we analyzed the hydrochemical composition, spatial distribution characteristics, and main control factors of the Xiaohuangni River and evaluated the solute contribution rates of different sources. The results showed that the pH of the Xiaohuangni River basin ranged between 7.17 to 9.14, with an average of 8.00, which is generally considered weakly alkaline. Additionally, the total dissolved solids ranged between 154 mg·L-1 to 460 mg·L-1, with an average of 257.39 mg·L-1, which was equivalent to that of the main stream of the Xijiang River. The dominant cation was Ca2+, accounting for 69% of the total cations; the dominant anions were HCO3- and SO42-, accounting for 65% and 30% of the total anions, respectively. The main chemical type of the main stream was HCO3-Ca. Affected by mining activities, the tributaries transitioned from HCO3-Ca to HCO3·SO4-Ca and HCO3·SO4-Ca·Na type. River water solute was mainly controlled by the weathering of carbonate rock and silicate rock, with the participation of sulfuric and carbonic acid. The contribution rate of carbonate weathering to river water solute was 63%, and that of silicate weathering was 16.33%. Meanwhile, human activities contributed markedly to the dissolved solutes of the Xiaohuangni River basin, in which the contribution rate of mining activities was 13.4%, and the contribution rate of agricultural activities and domestic sewage was 4%.

Multi-scale threat assessment of riverine ecosystems in the Colorado River Basin

Freshwater ecosystems are facing a deepening biodiversity crisis. Developing robust indicators to assess ecological integrity across large spatial scales and identifying the specific threats and pathways of impairment are thus critically needed if we are to inform freshwater conservation strategies. Here we present the first comprehensive threat assessment across the Colorado River Basin – one of the largest and most endangered river basins in North America – using a spatial framework accounting for the wide range of human activities (land uses, transportation infrastructure, exploitative activities, water withdrawals), pathways (local footprint, overland runoff, upstream cumulative effects), and spatial extent of influence (valley bottom, catchment and river network) known to affect the ecological integrity of riverine ecosystems. We quantified and mapped 69 individual threat indices with geospatial tools for each permanent, ephemeral, and intermittent stream segment within the Basin, encompassing a total of >1,067,700 river kilometers. We further aggregated these indices into components of water quality (diffuse and point-source pollution), hydrology (flow regulation/uses and climate change), and physical system (connectivity and geomorphology). To demonstrate the potential of our framework to inform spatial planning decision processes, we examined the typical combinations of threats experienced by different hydrologic areas and stream segment types, identified candidate watersheds for habitat restoration and enhancement where hotspots of biodiversity and threat overlapped, and assessed the associations between threat indices and in situ measurements of ecological integrity describing a suite of biological (benthic macroinvertebrate, fish), chemical (total nitrogen load, water conductivity), hydrological (flow alteration) and physical indicators (streambed stability, instream habitat complexity). Our assessment highlights clear disparities in term of overall degree of threat that result from different combinations and contributions of individual stressors, with different priorities emerging for perennial versus intermittent or ephemeral stream segments, and between the upper and lower parts of the Basin. Importantly, we showed that our threat indices were generally correlated with biological, chemical, hydrological and physical indicators of ecological integrity they were intended to capture. In addition to its implications for the conservation and management of the highly imperiled Colorado River Basin, our case study illustrates how multi-faceted threat mapping can be used to assess the ecological integrity of riverine ecosystems in the absence of spatially extensive in situ measurements.

Preliminary evaluation of pressurized hot water extraction for the solubilization of valuable components from hospital kitchen wastes

An alternative to mitigate the environmental impact of food waste is the separation of valuable components. Due to the difficulty and heterogeneity of such wastes, the study of model systems allowing a regular and predictable production and composition was used. A mixture of pre- and post-consumption kitchen wastes from a hospital with an automated organic matter segregation and drying system (HKW) has been collected to obtain representative samples of the different diets prepared daily. The chemical characterization of streams revealed a variation in composition of the wastes depending on the menus. Those from dinner + breakfast (D + B) presented protein content in the range 42–54% of the dry weight and those form lunch + snack (L + S) in the range 19–33%, whereas the carbohydrate content was 52–65% in D + B and 47–53% in L + S waste streams. These values suggested the possibility of proposing a different valorization scheme for each type of stream. In this study, a green extraction process with pressurized hot water under microwave heating has been explored for the solubilization of the most abundant and valuable components, protein, and carbohydrates. The starch fractions recovered from the crude extract were proposed for the formulation of anti-freezing hydrogels suitable for 3D printing, and the possibilities of valorizing other fractions such as proteins as plant biostimulants are also discussed.Graphical abstract

Indeks Kemiskinan Multidimensi Global: Analisis Menurut Perspektif Maqasid Syariah (Global Multidimensional Povety Index: An Analysis According to Maqasid Syariah Perspectives)

Poverty is often associated with the issue of lack of income. However, when questions such as "do children get the education they deserve?", "does a family get the right health services?" and "does the community receive the clean water and electricity supply it needs?" cannot be answered well, then it is a sign that poverty still exists from a multidimensional view. This study applies library methods, textual and contextual analysis methods by taking into the five elements of Shariah Maqasid in the context of multidimensional poverty and extracted based on inductive, deductive, and comparative methods. The results of the study show that multidimensional poverty has a direct relationship to Maqasid Syariah. All dimensions of multidimensional poverty such as education, health, and living standards have their importance in preserving the five elements of Maqasid Syariah, namely religion, intellect, soul, lineage, and property. In the education aspect, achievement in this aspect must take into account both types of educational streams, namely fardu ain and fardu kifayah. In the health aspect, emphasis is given to the prevention of disease as well as a balanced diet by taking into the source of treatment and halal supply for both. While in the aspect of living standards, the accumulation of wealth serves as a pillar to build a more prosperous life, providing benefits to human beings, rewards, and favors given by Allah SWT to his servants and is a test in human life. This study is seen to contribute to improving the shortcomings that exist in the existing multidimensional poverty measurement through the application of poverty measurement elements based on the perspective of Maqasid Syariah as an added value in creating a comprehensive multidimensional poverty measurement as discussed by Islam.

What Does the Livable City Sound Like? Analyzing Public Communication in Vancouver, Canada

Background: Livability has suffered from lack of engagement with the sensory aspects of urban life.Analysis: This article offers a content and discourse analysis of the keywords sound, noise, and livability found in two types of public communication streams in Vancouver, British Columbia, Canada: local news media and public city planning documents.Conclusion and implications: The analysis finds a critical missing link between neoliberal discourses on “livability” and considerations of sound and noise as important aspects of the urban experience. We suggest ways in which public discourses shape this gap, and how public communication on sound can inform richer considerations of urban livability.

CFD investigation of shock boundary layer interaction in hypersonic flow and flow control using micro ramps

PurposeThis study aims to investigate the prevalence of shock boundary layer interaction (SBLI) in air-breathing intake system is highly undesirable since this leads to high pressure gradients, typical stream mutilation and pressure drop. A novel flow control mechanism is incorporated in this research holding an array configuration of passive flow control device (micro ramps [MR]) that is adapted to improve the boundary layer stability.Design/methodology/approachTwo geometric variants of the MR, namely, MR40 and MR80 is considered which reduce the pressure drop during SBLI. The incidence oblique shock wave angle of 34° is considered for the modelling. Large eddy simulation (LES) turbulence model was used with subgrid models of Wall modelled LES, Smagorinsky–Lilly to compute the unsteady effects of SBLI control using micro vortex generators. The unsteady results are compared with steady Reynold’s average Naviers–Stoke’s equation for calibrating the turbulence models.FindingsThe array configuration of MR80 reduces the pressure drop by 22% as compared with no ramp configuration and also reduces the flow distortion in hypersonic inlet. The most affected region of the MR is in the vicinity of center-line. Quantitative results prove that the upstream influence of the shock waves has been largely reduces by MR80 array configuration as compared to single MR80 pattern configuration. Different vortex structures found in the experiments was exclusively predicted using LES.Originality/valueThis paper substantiates the requirement of MR array configuration for transferring the momentum from free stream to the boundary layer and thereby energizing the boundary layer. This process of energization delays the flow separation in hypersonic flow.

“Listen to me” – a systematic literature review about learning from others’ failure narrations

The dedicated stream of learning from others’ failure has gained increasing attention in entrepreneurship education research and—because of the COVID-19 crisis—among practitioners. The emerging literature on entrepreneurship education addresses this important phenomenon but lacks specific theoretical underpinnings; its new approaches to and empirical inquiry are one-sided. Therefore, a systematic literature review is warranted to provide a more comprehensive view of learning from others’ entrepreneurial failures and to develop a research model. Unprecedentedly, the author explores the type of research streams and gaps that can be included in a research model for entrepreneurship education research in the area of learning from others’ failures. The model is based on a systematic literature review analyzing 257 articles, which were narrowed down to 25 empirical articles focusing on university students’ learning from the entrepreneurial failures of others. The author argues that the literature lacks a holistic understanding of learning from others’ failures, especially regarding identifying new theories or new combinations of theories, and using methods other than experimentation and questionnaires. Therefore, the author develops a research model to overcome most of these gaps and identify important avenues for future research.

Distributed Multi Criteria Routed for MPLS-TE Based on Machine Learning: Concept and Applications

MPLS-TE Networks are complex interacting systems, providers integrate absolutely the forwarding equivalent class involving in the dynamic routing algorithm "Dynamic Multi Criteria Routing", especially with network services such as an IPtv, a VPNs or a VoIP with the several types of video streaming and similar user applications, making its flagship technologies of tomorrow. Machine learning is very compatible for this kind of networks. In this paper, we first review how the main machine learning concepts can be integrated in communication networks and discuss concepts, supervised and unsupervised model suitable to the network, data and management strategies, and creating a new architecture of network controls and management tools. We then describe case studies networking in detail, anticipate anomalies at multiple network layers, covering predictive maintenance, descriptive network topology management, capacity optimization. Finally, we prove the importance of this work, and guess an overview of intelligent dynamic networks.

A New Method for Surface-to-Air Video Detection and Tracking of Airborne Vehicles

Detection process of airborne targets may be thought simple because of the incompatible nature of aircraft, choppers, UAVs, and drones regarding clear sky background. When changes in the background are considered, brightness variation of the sky complicates the process. Changes in the shapes and types of clouds add another challenge to the process. Tracking process directly depends on the detection process and type of the data stream. The practical systems used for video detection and tracking of airborne targets are manual, and manual structures have some drawbacks compared to automatic structures. For video surveillance, guidance, regional security, and defense applications in dense environments, automatic detection and tracking process may be an obligation rather than preference. In this study, an automatic detection and tracking algorithm for video streams of airborne targets is proposed. A land-based moving camera captures the video data, and not only the flying objects but probably also the camera are in motion. Although the detection and tracking of moving objects via moving sensors is a relatively arduous task, this is the prevalent case in real-life scenarios. Video detection and tracking systems have one or more moving video sensors, while one or more flying air vehicles are in operation area. The proposed algorithm includes an image processing stage for detection and a tracking stage for initiation and continuation. An assessment study has been conducted for the actual video data and found that the proposed method yields successful results for detection, track formation, and continuation processes.

Research on the Business Model of Live Stream Marketing on e-Commerce Platform

With the popularization of mobile Internet and the improvement of streaming media technology, live streaming marketing has become a popular marketing method. In China, live stream marketing helped e-commerce merchants earn more than 100 billion yuan in sales revenue in 2018. This study focuses on analysing the differences in business models of different types of live stream marketing. Using the method of case study, the paper adopts a business model canvas to study the process of value creation, value transfer and value acquisition of anchor-oriented live stream marketing and brand-oriented live stream marketing respectively, and carries out the comparative analysis. The results of the case study summarize and compare the characteristics of the two live stream marketing business models, which makes up for the deficiency of discussion on live broadcast marketing business models in existing studies and provides suggestions regarding how to choose live stream marketing types for e-commerce platform merchants.

E-COMMERCE LIVE STREAMING – AN EMERGING INDUSTRY IN CHINA AND A POTENTIAL FUTURE TREND IN THE WORLD

With the widespread use of the Internet, many industries have developed rapidly. The economy based on the Internet poses a significant threat to the traditional economy. Live streaming plus e-commerce, which is acknowledged as the current global economic status, is the result of combing live streaming and various industries through the Internet. E-commerce live streaming is one of the most essential types of online live streaming. In this article, it is defined as the live streaming of the e-commerce platform used by Key Opinion Leaders or product sellers through the built-in live streaming function of the platform to propagate goods, brands, events, etc. to achieve goals of brand exposure and product sales. Compared with the traditional economic model, the combined model of e-commerce and live streaming has its advantages and characteristics. This kind of marketing tool is now prevalent. However, there are many deficiencies in e-commerce live streaming that need to be improved since the development of e-commerce is immature and supervision of Internet use is ongoing.