bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low‐Level Ice Clouds–Ice Fog
Authors: Gultepe Ismail 
Published: December 2019

Abstract
Ice clouds play an important role in the hydrological cycle and climate change, and their impact on water and heat cycle is crucial depending on their macro‐ and microphysical properties. As ice fog, it also affects weather conditions such as visibility.

Ice clouds and ice fog usually form at cold temperatures (
T
< 0 °C), and their nucleation processes usually take place at
T
< −5 °C. They occur extensively at colder
T
. They are usually composed of only ice crystals although mixed‐phase particle can be found down to −40 °C, and below that
T
, droplets can freeze up spontaneously. The development of ice clouds needs some level of dynamical activity, e.g. updrafts and thermal instabilities in a lifting moist air layer. Ice fog is composed of many small particles and has less water content compared to ice clouds. Its impact on economy and on Earth's heat budget is still not understood properly.
In situ
observation of ice cloud and their monitoring using remote‐sensing platforms such as radar, LiDAR, and satellites can improve their predictions and help develop algorithms to retrieve their physical properties.

In this article, the physical properties of ice cloud and ice fog are summarized using
in situ
and remote‐sensing observations, also focusing on the prediction issues related to forecast and climate models.
Groundwater Modeling
Authors: Holzbecher Ekkehard 
Published: December 2019

AbstractComputer models nowadays have become part of the common toolbox used in groundwater studies, concerning subsurface flow and transport processes. Analytical and numerical models are developed as solutions of differential equations, which are derived from basic principles and conservation laws. There are different finite discretization techniques to implement approximate solutions for differential equations and boundary conditions on a computer. Current modeling software, used by modelers for their work, not only includes solvers for equations but also various tools for pre‐ and postprocessing. The connections with other software, for surface water, for multispecies, for multiphysics, geo‐information systems, optimization, or parameter estimation are the current frontier of further development.
Water‐Jetting Drilling Technologies
Authors: Jacobs James A. 
Published: December 2019

Abstract

Water‐jet drilling or jetting has been used as a drilling method in both the developing world for water supply projects and in the United States for
in situ
remediation of hydrocarbons, chlorinated solvents, and metals. For the developing world, low‐cost, large diameter jetting is used for digging water supply wells. The technology only requires hand tools, such as wrenches, a water pump (electric, solar‐powered, fuel powered), flexible hoses with swivels, water source (in plastic‐lined pit or drums, for example), and a drill bit with pipe. Gravel pack for the well filter and polyvinyl chloride (PVC) pipe (screen and blank) are needed to complete the jetted well. For remediation, small diameter, high‐pressure (700 kPa or about 100 psi) 1–2 cm diameter drill wands are sued to pierce into the subsurface and deliver remediation chemicals into the soil and groundwater to treat a variety of contaminants.
Construction Sites: Stormwater Impacts from Runoff Water
Authors: Jacobs James A. 
Published: December 2019

Abstract
Construction sites can use industry best management practices (BMPs) to reduce turbidity in the stormwater runoff water which, if left untreated, can affect surface water. Groundwater can also be impacted from contaminated runoff water which infiltrates into the subsurface reaching shallow aquifers. Besides total suspended solids (TSS), runoff water from construction sites can solubilize petroleum hydrocarbons, chlorinated solvents, agricultural chemicals (such as pesticides, herbicides, and insecticides), nitrates, metals, as well as other contaminants. Fortunately, erosion control designs, employee training, and stormwater runoff prevention by BMPs can reduce the environmental impacts from water derived from construction sites. Snow and ice melting can create stormwater impacts by transporting sand, grit, and other traction compounds. Commonly used deicing compounds and the ubiquitous road salt are toxic to most freshwater aquatic life, and the impacts for shallow groundwater resources can be large. The rate of snow and ice melt can increase greatly on a warm day well above freezing, creating surface flooding and rapid subsurface infiltration. This article is an updated version of an earlier article from 2005.
Eutrophication and Nutrient Fluxes in Mediterranean Coastal Lagoons
Authors: Padedda Bachisio M. , Pulina Silvia , Satta Cecilia T. , Lugliè Antonella , Magni Paolo 
Published: December 2019

AbstractIn this article, we provide a general overview of eutrophication in aquatic ecosystems, with a focus on the Mediterranean Sea and two Sardinian lagoons (western Mediterranean Sea, Italy), as case studies. In the Cabras Lagoon, we assessed the nutrient budget and fluxes using the biogeochemical Land–Ocean Interaction Coastal Zone model. High nutrient and chlorophyll‐aconcentrations indicated eutrophic conditions, summer being the most critical season as related to the decrease in riverine water supply, the increase in water evaporation and a concurrent isolation of the lagoon from the adjacent sea. In the Calich Lagoon, the eutrophic conditions, assessed during 2008–2015, seemed to be attenuated by a good water exchange with the sea, yet potential harmful phytoplankton species were found. Overall, the present study shows how Mediterranean coastal lagoons are strongly influenced by both terrestrial and marine ecosystems. Eutrophication is one of the main forms of environmental degradation of aquatic ecosystems, and in coastal lagoons, this is the consequence of multiple pressures, which have led to significant losses of major ecosystem goods and services, such as aquaculture, fishery, and tourism. Good practices and landscape management are urgently needed to prevent further deterioration of these sensible ecosystems.
The Oceans: Ocean Circulation, Upwelling, and ENSO
Authors: Maurice Patricia A. 
Published: December 2019

Abstract
Water covers about 71% of the Earth's surface, and the oceans represent by far and away the largest reservoir of water. The oceans produce more than half of the oxygen in the atmosphere. They also take up carbon from the atmosphere, playing a huge role in the carbon cycle. The oceans strongly affect climate and weather patterns. This article is meant to serve as a brief introduction to the oceans, focusing primarily on ocean chemistry, ocean circulation, and the El Niño Southern Oscillation (ENSO). Other articles in the Encyclopedia cover many topics related to the oceans in much greater detail.
Chemical Kinetics in Environmental Systems
Authors: Maurice Patricia A. 
Published: December 2019

AbstractThe surface of the Earth is highly dynamic due to the influx of energy from the Sun coupled with radiogenic heat flow from the Earth's interior. This energy flux drives chemical reactions and helps to keep many environments and processes from attaining equilibrium. While many investigations of aqueous (geo)chemistry have focused on describing equilibrium conditions, it is also important to understand the rates of reactions, which is the realm of kinetics. This article provides a brief introduction to chemical kinetics in environmental systems as a backdrop for many of the other articles in the Encyclopedia dealing with topics such as microbial reactions, water treatment, acid mine drainage, etc. The focus here is on fundamental kinetic theory with some applications to topics such as mineral dissolution and adsorption. This article is drawn heavily from P. Maurice's 2009 book onEnvironmental Surfaces and Interfaces from the Nanoscale to the Global Scale, but substantially updated and expanded.
Pipe Failure Prediction with Consideration of Climate Change
Authors: Demissie Gizachew , Tesfamariam Solomon , Dibike Yonas , Sadiq Rehan 
Published: December 2019

AbstractRapidly changing climate combined with aging and deterioration of water supply system pipes present a significant challenge to most water utilities. Water transmission and distribution pipes are most often susceptible to the risk of failure because of their spatial diversity and inaccessibility with limited information available to understand their deterioration process. This article provides a modeling approach, Bayesian Model Averaging (BMA), for using climate projections in conjunction with other operational, physical, and environmental factors to predict/forecast cast iron (CI) pipe failure rates in the city of Calgary. The data from the city of Calgary, which constitutes operational factors, pipe physical attributes, and soil properties, and a statistically downscaled climate data from the Coupled Model Intercomparison Project phase 5 (CMIP5) are used for the demonstration of the developed BMA model. The result of parameter identification shows that the climatic parameters are found to be less sensitive; however, a significant change in sensitivity over time was exhibited during 1956–2014. The model results showed that there is a decrease in the failure rate for all CI pipes. However, the highest failure rate is expected for smaller‐diameter pipes compared to medium‐ and larger‐diameter pipes.
Use of
XAS
for Studies of Aqueous and Surface Geochemistry
Authors: Werellapatha Kalpani 
Published: December 2019

Abstract

X‐ray absorption spectroscopy (XAS) uses synchrotron X‐rays to provide local electronic, magnetic, and structural information about an element by exciting its core‐electrons either to the empty/nearly empty bound orbitals above the Fermi energy or to the continuum. Being element specific and sensitive to near neighbors, it provides a good contrast between different elements. Not requiring long‐range order makes it applicable to many disordered and dilute systems. Further, samples can be measured in environmental conditions and
in situ
, supporting investigations in aqueous and surface geochemistry. This article gives brief insights into basic theory of XAS spectroscopy, measurement methods, data analysis techniques and some instances of use of XAS in surface and aqueous geochemistry for beginner‐level students in various disciplines.
Crop Evapotranspiration
Authors: Todorović Mladen 
Published: December 2019

Abstract
Evapotranspiration is a process referring to water transfer from the land to the atmosphere by evaporation, from the soil surface, and by transpiration, through the vegetation. It is a complex process of great relevance for the hydrological balance at different scales. Nevertheless, it is difficult to measure and estimate; hence, almost all evapotranspiration data contains errors. The main biophysical principles of evapotranspiration are described together with the most relevant methods for measurement and estimation. Particular attention is given to crop evapotranspiration used in irrigation scheduling and agricultural water management. The estimation of crop evapotranspiration is presented following the two‐step approach based on crop coefficient and reference evapotranspiration. The concept of reference evapotranspiration is expounded by means of the Penman–Monteith approach that combines surface energy balance and aerodynamic principles of the process. The indicative data of crop coefficient and length of crop growing stages are reported in tables for most relevant agricultural crops and the world growing regions. A detailed description of calculation procedures for the estimation of reference and crop evapotranspiration is presented together with the methods to improve crop coefficient estimate under specific growing conditions. Finally, numerical examples of reference and crop evapotranspiration are given in Appendix 1.
Chemical Signaling in Aquatic Ecosystems
Authors: Lunsford Elias T. , Jenkins Karin , Ferrer Ryan P. 
Published: December 2019

AbstractChemical information mediates many of the biotic relationships that shape aquatic communities. Mate attractants and courtship pheromones determine successful reproductive encounters. Conspecific and environmental chemical cues influence the distribution of settling larvae and the ability of organisms to navigate across great distances to suitable habitat. Allelopathic agents can determine winners and losers in competition over resources, while signals transmitted between mutualists facilitate cooperation. Substances emitted from predators and prey provide early warnings of imminent threats to prey, while guiding predators to their next meal. Each of these individual interactions contributes to the dynamic nature of populations and communities in aquatic ecosystems. In this article, we provide an overview of the roles of chemistry and fluid dynamics in chemical ecology, and highlight several ecological interactions and life history events that are significantly affected by chemical cues, signals, and defenses. We offer examples from the literature that emphasize a multidisciplinary approach, when possible, and include promising future directions for research in large‐scale aquatic chemical ecology.
Unregulated Disinfection By‐Products: Spatiotemporal Variation in Water Distribution Networks
Authors: Chhipi‐Shrestha Gyan , Pokhrel Sarin R. , Kaur Manjot , Proulx Francois , Rodriguez Manuel J. 
Published: December 2019

Abstract
Residual disinfectants react with various natural organic matter in distribution networks (DNs) to form disinfection by‐products (DBPs), which are a public health concern. The regulated DBPs in various jurisdictions are trihalomethanes, haloacetic acids, bromate, and chlorate, which are mostly associated with chlorine. Owing to this, several alternative disinfectants, such as chloramines, ozone, and chlorine dioxide are also used. Although the use of alternate disinfectants has reduced the formation of regulated DBPs, these disinfectants have gathered much attention by introducing another cluster of DBPs known as unregulated DBPs (U‐DBPs). Many U‐DBPs are potentially toxic, mutagenic, and/or carcinogenic. This study reviews the models for predicting the spatiotemporal variation of U‐DBPs and analyzes their variability in DNs in the provinces of Quebec, and Newfoundland and Labrador, Canada. The findings show that limited predictive models are available for U‐DBPs compared to regulated DBPs. The concentrations of haloacetonitriles, chloropicrin, and haloketones significantly differed along the DNs based on the distance traveled and/or residence time. Similarly, temporal variability was significant in different seasons and in various weeks in summer but not significant by days from Monday to Friday. The formation of U‐DBPs can be controlled by source water protection, use of advanced treatment, alternative disinfectants, etc.
Groundwater Governance
Authors: Molle François , Closas Alvar 
Published: December 2019

AbstractGroundwater resources are being increasingly exploited around the world and patterns of overexploitation are widely observed. Long seen as the remit of hydrologists, groundwater is now understood as a key and politically disputed resource that supports domestic use, livelihoods, and high‐value commercial farming, as well as many wetlands and other groundwater‐dependant ecosystems. The governance of groundwater is complex due to its invisible and elusive nature, its fluctuating exchanges with surface water bodies, the diffuse nature of abstraction points, and the lack of state control over the individual initiatives that often arise in response to water shortages. Governance based on community‐, state‐, or market‐centered arrangements has tended to perform poorly. Comanagement shows some potential but is so far limited to specific physical‐cum‐political environments.
Vinyl Chloride in Groundwater: Chemical Behavior and Treatment
Authors: Jacobs James A. 
Published: December 2019

AbstractVinyl chloride (VC) is manufactured chlorinated solvent and is a chemical intermediate used in manufacturing of other items. VC is not a final product but is used to make polyvinyl chloride (PVC) plastic and vinyl products, including PVC pipes, packaging products, and wire and cable coatings as well as plastic furniture, vehicle upholstery and parts, house products, and wall coverings. VC has historically been used as a refrigerant but is no longer used for that purpose. Besides being a highly volatile and flammable liquid, human health exposure to VC is primarily through inhalation of VC‐contaminated air or ingestion of VC‐containing water or food. VC‐production workers may have dermal exposure through working with the chlorinated solvent. Liver toxicity and cancerous tumors are associated with VC which is a known human carcinogen. The U.S. Environmental Protection Agency (U.S. EPA) maximum contaminant level (MCL) for vinyl chloride is 2 μg L−1or 2 parts per billion (ppb), which is lower than the associated tetrachloroethylene (PCE) and trichloroethylene (TCE) MCL of 5 μg L−1or 5 ppb.
Life Cycle for Groundwater Remediation Projects
Authors: Jacobs James A. 
Published: December 2019

Abstract
During the past few decades, the groundwater remediation project life cycle has been used in many countries to characterize the status of an environmental remediation project. If groundwater or soil contamination is suspected, a general process from assessment to closure occurs. Although the timing and specific activities may vary from site to site, a general phased process occurs. Environmental evaluations of potential leakage or spillage of hazardous substances into the subsurface generally consist of four phases (Phase I through Phase IV), which are described in this article.
In Situ
Bioremediation of Groundwater: Process Limitations
Authors: Vance David B. , Jacobs James A. 
Published: December 2019

Abstract
This article deals with bioremediation of hydrocarbon contaminants in groundwater. Two types of hydrocarbons are addressed: petroleum hydrocarbons and complex chlorinated hydrocarbons. Factors that must be optimized for successful bioremediation are discussed in detail.
Phytoremediation Enhancement of Natural Attenuation Processes
Authors: Vance David B. , Jacobs James A. 
Published: December 2019

Abstract

Phytoremediation is the use of living green plants for
in situ
remediation of contaminants using what is in essence enhanced natural attenuation for soil and groundwater cleanup. There are a variety of phytoremediation methods, some having multiple names: phytostabilization, rhizodegradation (phytostimulation, rhizosphere bioremediation, or plant‐assisted bioremediation), rhizofiltration (contaminant uptake), phytodegradation (phytotransformation), phytovolatilization, and phytoaccumulation (phytoextraction or hyperaccumulation). Various types of plants can be used in phytoremediation, including poplar trees, alfalfa, black locust, Indian mustard, fescue grass, crested wheatgrass, and Canada wild rye. This article reviews phytoremediation methods as applied to organic contaminants and heavy metals.
MassiveMIMOFundamentals
Authors: Ngo Hien Quoc 
Published: December 2019

AbstractMassive multiple‐input and multiple‐output (MIMO) is a scalable version of multiuser MIMO where the base stations are equipped with many antennas. It provides very high array gain and multiplexing gain and, hence, offers huge spectral and energy efficiency. In addition, by exploiting favorable propagation and channel hardening properties, simple linear processing can obtain nearly optimal performance that makes massive MIMO easy to implement in practice. Therefore, massive MIMO has gained significant research attention over the past 10 years and became one of the key technologies for fifth‐generation (5G) networks and beyond. Very recently, a massive MIMO system with 64‐antenna base station has been commercially deployed for 5G. In this article, we present a comprehensive overview of state‐of‐the‐art research on massive MIMO. Fundamental aspects of this system will be discussed in detail. The discussion will serve as a good roadmap for start‐up and consequently motivate researchers from both industry and academia to work in this area. First, we provide the basic transmission protocol of massive MIMO system under time‐division duplex operation. Then, the derivations of spectral efficiency using the well‐known “use‐and‐then‐forget bounding” technique in massive MIMO are reviewed. Duplexing operations, favorable propagation, channel hardening, and pilot contamination are also detailed. Finally, we conclude with a range of important topics and future directions.
Core and Transport Network Slicing
Authors: Querio Roberto , Di Giglio Andrea , Madella Mario , Moggio Fabrizio , Boldi Mauro 
Published: December 2019

AbstractA specific feature of the 5G systems is the ability to serve very different industry needs by satisfying their specific requirements in a single network. A wide range of services can be simultaneously offered by the same 5G network, thanks to the deployment logical end‐to‐end network slices on a common infrastructure. All the domains of a telecommunication network, i.e. access, transport and core network, are touched upon by the architectural solution to support end‐to‐end network slicing (of which core and transport are covered in this article). Each of the mentioned domains evolved in the last few years to define and provide the key technologies enablers, described in the article, to reach the level of dynamicity and flexibility promised by 5G network slicing. Management and orchestration layer also needed to evolve in order to support the features necessary to integrate the core and transport network domains to provide a real end‐to‐end architecture.
Service Chaining Using Software‐Defined Networks
Authors: Petroulakis Nikolaos , Fysarakis Konstantinos , Miaoudakis Andreas , Ramantas Konstantinos , Chatziadam Panos , Verikoukis Christos 
Published: December 2019

AbstractThe innovative capabilities of 5G technologies, such as software‐defined networking (SDN) and network function virtualization (NFV), open up a variety of possibilities for improved and novel service provisioning. Nevertheless, technologies such as SDN expand the attack surface of the communication infrastructure, thus necessitating the introduction of additional security mechanisms. These major changes affect various domains, such as industrial and healthcare environments, where smart deployments gradually become a reality. Motivated by the above, this article highlights the benefit of leveraging the flexibility of SDN/NFV‐enabled networks to deploy enhanced, reactive networking functions to provide security and performance guarantees, via the use of service function chaining (SFC). To this extent, an implementation of a reactive security framework is presented. The application of such a framework in two use cases is also presented: The first use case is in a wind park, which is a good example of an industrial application relying on a network with strict performance, security, and reliability requirements. The second use case is related to ambient‐assisted living, a domain promising significant improvements in the health and well‐being of elderly populations, but which also comes with intrinsic security, safety, and privacy concerns.