Flexible management of hydropower plants would contribute to a secure electricity supply

A study by the UPV/EHU-University of the Basque Country and BC3 explores ways of ensuring power supply in a future without nuclear and coal-fired stations

UNIVERSITY OF THE BASQUE COUNTRY

IMAGE: THE POSSIBILITIES OFFERED BY HYDRAULIC ENERGY TO ENSURE SECURITY OF ELECTRICITY SUPPLY ARE BEING STUDIED IN DEPTH. view more 

CREDIT: DIEGO CERVO / STOCKFRESH

Researchers from the UPV/EHU's Institute of Public Economics and BC3, the Basque Centre for Climate Change, have been cooperating for several years on the study and projection of so-called security of electricity supply in Spain. The country is regarded as an "electricity island" owing to its scant interconnection with neighbouring countries. This feature underlies the projections of the country's power demand, generation capacity, and supply over the coming decades. Drawing on these projections the researchers evaluate the degree of security of supply and assess how it will change in response to the sources of electricity that are gradually abandoned or promoted. The scientific journal Energy has recently published the second article relating to this study in which another two BC3 researchers have taken part.

Starting from known values of power consumption and generation the group of researchers developed a model to project the evolution of these two variables in 2020, 2030, 2040 and 2050. "Other authors have made projections of electricity consumption and reckon that it will grow one decade after another, a bit more than 1% per year. With respect to electricity sources, for the next 10 years the projections indicate that coal and nuclear will undergo a sizeable reduction, and by 2040 these two technologies will cease operation," said José Manuel Chamorro-Gómez, from the UPV/EHU's Institute of Public Economics. The former loss in generation capacity will be offset by an increase in renewables. Further, "the capacity of all the renewable plants due to come into operation will be greater than the one now available of non-renewable generation, but everything seems to suggest that the security of supply will nonetheless be affected", added the researcher.

By their very nature, renewable power sources are intermittent, uncertain, and non-dispatchable. All of these features impinge on the system and increase the risk that a fraction of demand will not be met by the available sources, which renders the supply less secure. "Right now, the existing system does not guarantee 100% of supply in any scenario, but in our models we have seen that the potentially unmet fraction will be much bigger in the future, and supply shortages will be more frequent," said the researcher.

In this study they explored thoroughly the possibilities offered by a source of renewable energy that lends itself to a more flexible management, namely hydropower. "Hydro plants can be adjusted by the people in charge of operating them; the flow of water to the turbine can be regulated at any moment, which, no doubt, would partly alleviate the risk of a supply shortage. Furthermore, hydro stations with reversible turbines play a dual purpose: in addition to increasing power generation at times of higher demand, when this is lower the turbine can be used to pump water upwards to the reservoir (by using electricity); this way, water can be stored and used later on to generate electricity once more when demand increases again. According to our results, that would alleviate, to a certain extent, the risk of being unable to meet demand when it surges," he argued.

However, the authors also refer to the environmental aspects that have to be taken into account when addressing and planning the use and operation of hydro stations. "From the viewpoint of power generation, water is obviously a resource, but this resource is of course in a context. The impact that power plants and reservoirs have on river basins is undeniable. So the administrations or policy makers above the station operators have to set the rules of the game, and these rules need to be clear in terms of ecological flows, discharge frequencies and other parameters," said Chamorro.

Besides the resource of hydro plants, the researcher listed another series of measures that could be adopted to fully address demand, thus guaranteeing security of supply. "Firstly, much research is being conducted on electricity storage. If you can come up with a system in which, say, you store the electricity generated by the wind during a period of low demand, you will have a way of using it when needed. Or you can encourage consumers to use their household appliances during non-peak hours when the price of electricity is lower. Furthermore, electric vehicles could feed their charge into the grid at a given moment to supplement supply. Progress is being made in different aspects to achieve a system in which demand peaks are met as fully as possible," he concluded.

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Additional information

José Manuel Chamorro-Gómez, a member of the UPV/EHU's Institute of Public Economics, and Luis María Abadie-Muñoz, researcher at the Basque Centre for Climate Change (BC3), keep a close cooperation from long ago in studies about energy and climate economics. Sébastien Huclin and Dirk-Jan van de Ven, two experts in hydraulic resources at BC3, collaborated in their latest piece of work.

Fuel from disused tyres

Research from the UPV/EHU-University of the Basque Country is seeking a solution for used tyres by means of catalytic pyrolysis

UNIVERSITY OF THE BASQUE COUNTRY

 

Used tyres pose a serious environmental risk owing to the damage that may be caused when they are stored in the environment. They are emerging in ever greater numbers from one year to the next in developed countries so revalorizing them is a subject that is attracting great interest and is being spurred on by the increasingly stringent regulations in terms of their management.

"Pyrolysis is a hugely interesting alternative when it comes to revalorizing tyre materials in order to obtain alternative fuels and petrochemical products with high added value. In this context, pyrolysis involves degrading the rubber of the tyre by applying heat in the absence of oxygen. The products and their yield depend on the conditions in which the pyrolysis is carried out," said Miriam Arabiourrutia-Gallastegui, lecturer in the UPV/EHU's PROCAT-VARES (Catalytic Processes-Waste Valorization) group.

In a paper recently published in the journal Renewable and Sustainable Energy Reviews, the research group analysed the most important advantages in valorizing used tyres using catalytic pyrolysis. "The main interest in valorizing tyre waste by pyrolysis is based on the potential of the products obtained: gas, liquid and a solid known as char. The yield and composition of each of them depend on the pyrolysis conditions," said Arabiourrutia.

"Liquid is the main product obtained in catalytic pyrolysis. This liquid is basically what is of the greatest interest because it could be used as fuel if it were to be incorporated, for example, into a refinery. Its composition is complex and includes compounds of different types (aromatics, paraffins, olefins and naphthenes), plus sulphur compounds that limit its direct use as a fuel. So the interest in catalytic pyrolysis tends to be linked to the improvement in the properties or yield of this part. So with respect to catalytic pyrolysis great interest has been placed in the production of chemical products, such as aromatic compounds (benzene, toluene, etc.), because they have commercial applications," explained the UPV/EHU researcher.

"Pyrolysis gases can also be used as fuel to produce energy. Finally, char is the solid left behind that is not degraded and mainly comprises the carbon black present in the tyre; carbon black is the compound that provides the tyre with its anti-abrasive properties. The possible activation of char for use as activated carbon is being explored; it could be reused as carbon black in the manufacture of tyres," Arabiourrutia added.

"In the process we used and based on the use of the conical spouted bed reactor, catalytic pyrolysis has certain, very specific conditions: the time the gases generated remain in the reactor is short and that promotes a series of reactions which, for example, lead to the production of a high yield of the liquid part. We have also seen that, more than anything, this process enables the liquid product obtained to be used in refineries to obtain fuel," stressed Miriam Arabiourrutia-Gallastegui.

As the researcher pointed out, "thanks to all these pieces of work we are gradually adjusting and improving the pyrolysis process to try and bring about a distribution of products with a more suitable composition with a view to their potential application as fuel or raw material to obtain compounds of interest".

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Additional information

The PROCAT-VARES group is involved in proposals, progress and innovation in processes of interest in terms of energy and the environment. The aim is to develop lines of research that are a benchmark on an international level in Chemical Reaction Engineering, are highly topical and focus on sustainable development. This activity involves training researchers and technologists, transferring knowledge to the international scientific and technological community in the form of publications, and collaborating with the industrial sector in matters combining subjects of academic, technological, social and industrial interest.

'Roaming reactions' study to shed new light on atmospheric molecules

UNIVERSITY OF NEW SOUTH WALES

 

A detailed study of roaming reactions - where atoms of compounds split off and orbit other atoms to form unexpected new compounds - could enable scientists to make much more accurate predictions about molecules in the atmosphere, including models of climate change, urban pollution and ozone depletion.

In a paper published today in the journal Science, a team of researchers from UNSW Sydney, University of Sydney, Emory University and Cornell University showed in unprecedented detail exactly what happens during roaming reactions of chemical compounds.

Professor Scott Kable, an atmospheric scientist who is also the head of UNSW's School of Chemistry, likens the study to lifting the hood on roaming reactions and seeing for the first time how the parts fit together. He says the study will give scientists new tools to understand the machinations of reactions in the atmosphere.

"Chemical reactions, where atoms are rearranged to make new substances, are occurring all the time in our atmosphere as a result of natural emission from plants and animals as well as human activity," Prof Kable says.

"Many of the key reactions in the atmosphere that contribute to photochemical smog and the production of carbon dioxide are initiated by sunlight, which can split molecules apart.

"For a long time, scientists thought these reactions happened in a simple way, that sunlight was absorbed and then the molecule explodes, sending atoms in different directions.

"But, in the last few years it was found that, where the energy from the sun was only just enough to break a chemical bond, the fragments perform an intimate dance before exchanging atoms and creating new, unanticipated, chemical products - known as roaming reactions.

"Our research shows these 'roaming' reactions exhibit unusual and unexpected features."

Prof Kable says in an experiment detailed in the paper, the researchers looked at the roaming reaction in formaldehyde (CH2O) and were surprised to see instead, two quite distinct signals, "which we could interpret as two distinct roaming mechanisms".

Professor Joel Bowman, who oversaw simulations of the roaming reactions at Emory University in the US, observed that that "detailed modelling of these reactions not only agree with the experimental findings, they provide insight into the motion of the atoms during the reaction". Simulations of the experiment were also carried out at Cornell University (US).

Professor Meredith Jordan from University of Sydney says the experiments and theory results suggest roaming reactions straddle the classical and quantum worlds of physics and chemistry.

"Analysing the results with the incredible detail in both experiments and simulations allowed us to understand the quantum mechanical nature of roaming reactions. We expect these characteristics to be present in all roaming reactions," she says.

The results of this study will provide theoreticians with the data needed to hone their theories, which in turn will allow scientists to accurately predict the outcomes of sunlight-initiated reactions in the atmosphere.

Prof Kable says the study could also benefit scientists working in the areas of combustion and astrophysics, who use complex models to describe how molecules interact with each other in gaseous form.

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The paper, titled "Rotational resonances in the H2CO roaming reaction are revealed by detailed correlations" is published online by the journal Science. It can be accessed at https://science.sciencemag.org/content/early/2020/08/05/science.abc4088

First record of invasive shell-boring worm in the Wadden Sea means trouble for oyster

ROYAL NETHERLANDS INSTITUTE FOR SEA RESEARCH

 

IMAGE: MUD BLISTERS CAUSED BY POLYDORA WEBSTERI. view more 

CREDIT: DAGMAR LACKSCHEWITZ

In October 2014, the suspicion arose that the parasite worm Polydora websteri had found its way to the Wadden Sea. Following years of research, that suspicion has now been confirmed: the worm, that likely originates from the Asian Pacific, has arrived in European waters. Researchers from the German Alfred Wegener Institute (AWI) and the Royal Netherlands Institute for Sea Research (NIOZ), confirm in a publication in Marine Biodiversity, that they have found the shell-borer in oysters near Sylt and Texel and speculate that it is likely to have spread much further.

'Trouble maker' leaves oyster unsellable

The worm Polydora websteri is a known 'trouble maker' that causes mud blisters as it bores its way through an oyster's shell, leaving the oyster vulnerable for predators in the wild, and unsellable on the market. Thieltges: 'The worm manoeuvres between the inner and outer world of the oyster. It isn't strictly speaking a parasite as it leaves the oyster's body in peace, but by attacking its shell, it drains the energy of the oyster that now needs to focus on its repair.' Wild populations of Pacific oysters, exotic species that were themselves introduced to the Wadden Sea ecosystem in the 1970s and '80s, have till now been rather safe from predators. The worm might change this. The oysters might be weakened and their shell softened, making them easier prey for crabs and birds. On the long-term, this could mean a shift in the ecosystem.

While the worm might form a big threat to aquaculture farming, it is also likely that aquaculture itself acted as the primary vector of introduction. NIOZ researcher and co-author David Thieltges: 'A large part of the invasive species in the marine ecosystem arrive with the import of commercial species and the transfer of farmed specimens between aquaculture sites.' The worm's favourite host, the Pacific oyster, is traded and cultured globally. By moving the oyster, the worm, though not -intended, becomes an international traveller as well. The researchers, including Thieltges and AWI-scientist Andreas Waser, found the first Polydora websteri in the direct vicinity of an oyster farm that imports juvenile oysters from a nursery in southern Ireland. Their travel path illustrates the global character of the trade. Thieltges and Waser: 'This site of the first record was also the site with the highest infestation. We suspect that the arrival of the worm in the northern Wadden Sea may be related to the oyster imports.'

Polydora websteri drilling mud blisters in a Pacific oyster.

Here to stay and to be reckoned with

Once introduced, the further spread of invasive species can continue either via dispersal of larval stages or human-aided secondary vectors such as fouling on ship hulls. This may explain that the worm was also found during sampling at the Mokbaai on Texel, an island without oyster farms. Thieltges underlines, that it is unlikely that the worms found near Texel came from Sylt. 'That they made their way from Sylt to Texel, along almost 500 kilometres of coastline, seems rather unlikely. We think there might be a different origin.'

An option would be that larval stages of the worms found in the Dutch Wadden Sea came from Zeeland where there is commercial oyster aquaculture. However, the team still needs to investigate whether the worm is already present in Zeeland as well.' Thieltges: 'Sampling at other places in the Netherlands and in Europe together with genetic research is now needed to establish the origin and distribution of the worm. We don't know its exact origins yet, but we know that it's here and that it is very likely to keep extending its range.'

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COVID-19: The long road to recovery

UNIVERSITY OF LEEDS

Researchers have identified a pattern of longer-term symptoms likely to be experienced by people who were hospitalised with the COVID-19 infection.

They include fatigue, breathlessness, psychological distress - including problems with concentration and memory - and a general decline in quality of life.

Some patients, particularly those who had been in intensive care, had symptoms associated with cases of PTSD (post-traumatic stress disorder).

The findings provide the first detailed insight into problems facing patients recovering from COVID-19 in the UK.

Dr Manoj Sivan, Associate Clinical Professor at the University of Leeds and a Consultant in Rehabilitation Medicine at Leeds General Infirmary, supervised the research project. He said: "COVID-19 is a new illness and we have very little information on longer term problems in individuals after discharge from hospital."

"The emerging evidence is that for some, the road to recovery may take months and it is vital specialist rehabilitation is on hand to support them. This research gives an important insight into patient needs, and that will help shape services in the community."

The findings - Post-discharge symptoms and rehabilitation needs in survivors of COVID-19 infection: a cross-sectional evaluation - have been published in the Journal of Medical Virology.

Dr Stephen Halpin, Senior Research Fellow at the University of Leeds and Consultant with Leeds Teachings Hospitals NHS Trust, said: "This research follows our previous work of predicting COVID-19 patients' long-term needs based on previous coronavirus outbreaks of SARS in 2002 and MERS in 2012. The health problems are similar but on a larger scale given the number of people affected."

The research team - involving multidisciplinary specialists from the University of Leeds, Leeds Teaching Hospitals NHS Trust, Leeds Community Healthcare NHS Trust and Leeds Beckett University - followed 100 people recovering from COVID-19, four-to-eight weeks after being discharged from hospital in Leeds.

The COVID-19 survivors were divided into two groups: those who had become critically ill and needed intensive care - 32 people were in this category; and those who were treated on a ward without needing intensive care - 68 people were in this category.

Patients were contacted by a member of the hospital's rehabilitation team and asked a series of questions about their recovery and symptoms they were still experiencing.

Results

The most prevalent symptom was fatigue. More than 60 percent of people who had been treated on a ward reported fatigue, and one-third of them described it as moderate or severe. For patients who had been in intensive care, 72 percent reported fatigue. Of those, more than half said it was moderate or severe.

The second most common symptom was breathlessness. People in both groups said they had feelings of breathlessness which had not existed before they contracted COVID-19. This was higher in the group that had been the most ill, the intensive care group versus those who had been treated in a ward - 65.6 percent versus 42.6 percent.

The third most prevalent symptoms were neuropsychological. The research survey found that almost one quarter of the people who had been on a ward and just under a half of the people who had been in intensive care had some of the symptoms of PTSD.

Writing in the paper, the researchers said: "PTSD symptoms are a well-recognised component of post- intensive care unit syndrome caused by a variety of factors including fear of dying, invasive treatment, pain, delirium, inability to communicate, weakness, immobility, and sensory problems and sleep deprivation."

More than two-thirds (68.8 percent) of patients in the intensive care group and just under half (45.6 percent) of the other group said their overall quality of life had deteriorated.

The researchers say the rehabilitation needs of patients who did not require hospital care need to be further investigated and they are working on understanding this in future research.

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New study sheds light on evolution of hell ants from 100 million years ago

CHINESE ACADEMY OF SCIENCES HEADQUARTERS

IMAGE: PHYLOGENY AND CEPHALIC HOMOLOGY OF HELL ANTS AND MODERN LINEAGES. view more 

CREDIT: NIGPAS

Ants are the most successful social insects and play an important role in modern terrestrial ecosystems. The origin and early evolution of ants have attracted lots of attention.

Among the earliest fossil ants known, haidomyrmecine "hell ants" from Cretaceous amber reveal an ancient and dramatic early burst radiation of adaptive forms.

Hell ants possessed bizarre scythe-like mouthparts along with a striking array of horn-like cephalic projections. But how did this type of ant evolve? This question was long a mystery.

Now, however, an international research team co-led by Prof. WANG Bo from the Nanjing Institute of Geology and Palaeontology (NIGPAS) of the Chinese Academy of Sciences has confirmed the special trap-jaw predation mechanism of hell ants, providing new insights into their evolution.

The study was published in Current Biology on August 6.

The research team conducted morphological and anatomical analysis of the heads of all hell ants in the amber specimens, in combination with a special predator specimen, and confirmed the "trap-jaw" predation mechanism adopted by hell ants from their morphological and functional aspects.

The scientists reported an instance of fossilized predation that provides direct evidence for the function of dorsoventrally expanded mandibles and elaborate horns.

Their findings confirmed the hypothesis that hell ants captured other arthropods between mandible and horn in a manner that could only be achieved by articulating their mouthparts in an axial plane perpendicular to that of modern ants.

The head capsule and mandibles of hell ants are uniquely integrated as a consequence of this predatory mode and covary across species, while no evidence has been found of such modular integration in extant ant groups.

The results of this study suggest an extinct early burst adaptive radiation into morphospace that was unoccupied by any living taxon. This radiation was triggered by an innovation in mouthpart movement and subsequent modular covariation between mandible and horn.

The new results also suggest that hell ant cephalic integration - analogous to the vertebrate skull - triggered a pathway for an ancient adaptive radiation and expansion into morphospace unoccupied by any living taxon.

New fossil discovery shows how ancient 'hell ants' hunted with headgear

In a 99-million-year-old preserved amber fossil, researchers get a detailed glimpse into how 'Hell Ants' hunted with scythe-like mandibles and horn appendages

NEW JERSEY INSTITUTE OF TECHNOLOGY

 

IMAGE: RESEARCHERS DISCOVER A WORKER OF THE HELL ANT CERATOMYRMEX ELLENBERGERI GRASPING A NYMPH OF CAPUTORAPTOR ELEGANS (ALIENOPTERA) PRESERVED IN AMBER DATED TO ~99 MA. view more 

CREDIT: NJIT, CHINESE ACADEMY OF SCIENCES AND UNIVERSITY OF RENNES, FRANCE

In findings published Aug. 6 in the journal Current Biology, researchers from New Jersey Institute of Technology (NJIT), Chinese Academy of Sciences and University of Rennes in France have unveiled a stunning 99-million-year-old fossil pristinely preserving an enigmatic insect predator from the Cretaceous Period -- a 'hell ant' (haidomyrmecine) -- as it embraced its unsuspecting final victim, an extinct relative of the cockroach known as Caputoraptor elegans.

The ancient encounter, locked in amber recovered from Myanmar, offers a detailed glimpse at a newly identified prehistoric ant species Ceratomyrmex ellenbergeri, and presents some of the first direct evidence showing how it and other hell ants once used their killer features -- snapping their bizarre, but deadly, scythe-like mandibles in a vertical motion to pin prey against their horn-like appendages.

Researchers say the rare fossil demonstrating the hell ant's feeding mode offers a possible evolutionary explanation for its unusual morphology and highlights a key difference between some of the earliest ant relatives and their modern counterparts, which today uniformly feature mouthparts that grasp by moving together laterally. The hell ant lineage, along with their striking predatory traits, are suspected to have vanished along with many other early ant groups during periods of ecological change around the Cretaceous-Paleogene extinction event 65 million years ago.

"Fossilized behavior is exceedingly rare, predation especially so. As paleontologists, we speculate about the function of ancient adaptations using available evidence, but to see an extinct predator caught in the act of capturing its prey is invaluable," said Phillip Barden, assistant professor at NJIT's Department of Biological Sciences and lead author of the study. "This fossilized predation confirms our hypothesis for how hell ant mouthparts worked ... The only way for prey to be captured in such an arrangement is for the ant mouthparts to move up and downward in a direction unlike that of all living ants and nearly all insects."

"Since the first hell ant was unearthed about a hundred years ago, it's been a mystery as to why these extinct animals are so distinct from the ants we have today," Barden added. "This fossil reveals the mechanism behind what we might call an 'evolutionary experiment,' and although we see numerous such experiments in the fossil record, we often don't have a clear picture of the evolutionary pathway that led to them."

Driving Diversity of Hell Ants & Their Headgear

Barden's team suggests that adaptations for prey-capture likely explain the rich diversity of mandibles and horns observed in the 16 species of hell ants identified to date. Some taxa with unarmed, elongate horns such as Ceratomyrmex apparently grasped prey externally, while other hell ants such as Linguamyrmex vladi, or "Vlad the Impaler" discovered by Barden and colleagues in 2017, was thought to have used a metal-reinforced horn on its head to impale prey -- a trait potentially used to feed on the internal liquid (hemolymph) of insects.

Barden says the earliest hell ant ancestors would have first gained the ability to move their mouthparts vertically. This, in turn, would functionally integrate the mouthparts and head in a way that was unique to this extinct lineage.

"Integration is a powerful shaping force in evolutionary biology ... when anatomical parts function together for the first time, this opens up new evolutionary trajectories as the two features evolve in concert," explained Barden. "The consequences of this innovation in mouthpart movement with the hell ants are remarkable. While no modern ants have horns of any kind, some species of hell ant possess horns coated with serrated teeth, and others like Vlad are suspected to have reinforced its horn with metal to prevent its own bite from impaling itself."

To explore further, the researchers compared the head and mouthpart morphology of Ceratomyrmex and several other hell ant species (such as head, horn and mandible size) with similar datasets of living and fossil ant species. The team also conducted a phylogenetic analysis to reconstruct evolutionary relationships among both Cretaceous and modern ants. The team's analyses confirmed that hell ants belong to one of the earliest branches of the ant evolutionary tree and are each other's closest relatives. Moreover, the relationship between mandible and head morphology is unique in hell ants compared to living lineages as a result of their specialized prey-capture behavior. The analyses also demonstrated that elongated horns evolved twice in hell ants.

While the fossil has finally provided Barden's lab with firmer answers as to how this long-lost class of ant predators functioned and found success for nearly 20 million years, questions persist such as what led these and other lineages to go extinct while modern ants flourished into the ubiquitous insects we know today. Barden's team is now seeking to describe species from new fossil deposits to learn more about how extinction impacts groups differentially.

"Over 99% of all species that have ever lived have gone extinct," said Barden. "As our planet undergoes its sixth mass extinction event, it's important that we work to understand extinct diversity and what might allow certain lineages to persist while others drop out. I think fossil insects are a reminder that even something as ubiquitous and familiar as ants have undergone extinction."

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Barden et al., Specialized Predation Drives Aberrant Morphological Integration and Diversity in the Earliest Ants, Current Biology (2020), https://doi.org/10.1016/j.cub.2020.06.106

Researchers: What's in oilfield wastewater matters for injection-induced earthquakes

VIRGINIA TECH

 

IMAGE: IN THIS APRIL 2019 PHOTO, ASSISTANT PROFESSOR RYAN POLLYEA (STANDING) TEACHES UNDERGRADUATE STUDENTS ABOUT PERMEABILITY IN THE LAB SECTION OF GROUNDWATER HYDROLOGY (GEOS 4804). view more 

CREDIT: VIRGINIA TECH

A team of geoscience researchers in the Virginia Tech College of Science has developed a new theory to explain how and why injection-induced earthquakes continue to occur even when injection rates decline.

Experts have known since the 1960s that when oilfield wastewater is pumped into the ground with deep injection wells, earthquakes can occur. Over the past decade, injection-induced earthquakes have become regular occurrences throughout oil and gas basins worldwide, particularly in the central United States, and potentially in China and Canada, as well.

Oil and gas production are often accompanied by highly brackish groundwater, also known as oilfield brine. These fluids can be five to six times saltier than seawater, so they are toxic to terrestrial ecosystems and have little beneficial use. As a result, oilfield brine is considered to be a waste product that is disposed of by pumping it back into deep geologic formations.

When fluids are pumped into deep injection wells, they alter the naturally occurring fluid pressure in deep geologic formations. These fluid pressure changes can destabilize faults, leading to earthquakes, such as the damaging magnitude-5.8 event in Pawnee, Oklahoma, in September 2016.

Among the more vexing scientific questions about injection-induced earthquakes is why they seem to be getting deeper in such places as Oklahoma and Kansas, where injection rates have been declining due to a combination of earthquake mitigation measures and declining oil and gas production.

In a study published Aug. 5 in Energy & Environmental Science, Ryan M. Pollyea, assistant professor in the Department of Geosciences, and a team of student researchers proposed a new theory that the wastewater itself plays an important role in the processes that cause injection-induced earthquakes.

"We know that earthquakes are getting deeper in Oklahoma," said Pollyea, who directs the Computational Geofluids Lab at Virginia Tech, "so we're trying to figure out what conditions make this possible. Our research suggests that it's caused by combination of the geology, natural fluids in the basement rocks, and the wastewater itself."

Although researchers have known for decades that deep fluid injections can trigger earthquakes, Pollyea said previous research misses some consequential details about how they occur. Specifically, he pointed out that oilfield brine has much different properties, like density and viscosity, than pure water, and these differences affect the processes that cause fluid pressure to trigger earthquakes.

"The basic idea is that oilfield brine has a lot of dissolved solid material, which makes the wastewater heavier than naturally occurring fluids in deep geologic formations," said Richard S. Jayne, a co-author of the study and former Ph.D. student at Virginia Tech who is now a research hydrogeologist at Sandia National Laboratory, "so the dense wastewater sinks, increases fluid pressure, and causes deeper earthquakes than would be predicted if the fluids have the same material properties."

Using supercomputers at Virginia Tech's Advanced Research Computing division, Pollyea and his team tested their idea by producing more than 100 models of oilfield wastewater disposal using various combinations of geologic properties, wastewater temperature, and wastewater density. With this computational approach, the team isolated both the conditions and physical processes that alter fluid pressure in the geologic formations.

"We found that there are really two different processes that drive fluid pressure deep into the basement, where earthquakes occur," saids Pollyea. "The first is called pressure diffusion, which occurs when wastewater is forced into geologic formations that are already full of water. This process has been known for a long time, but the second process occurs when high-density wastewater sinks and pushes lower density fluids out of the way."

According to this new theory, the density difference between wastewater and deep basement fluids is much more important for induced earthquake occurrence than was previously known. "This is one of the areas that has been neglected in induced-seismicity research," said Megan Brown, an assistant professor of geology who specializes in fluid triggered seismicity at Northern Illinois University and was not involved in this study. "Density-driven pressure transients are an intuitive consequence of a density differential between injected fluids and formation fluids."

Although earthquake occurrence has been decreasing in the central U.S. since the peak years of 2014 and 2015, this new theory not only explains why earthquakes are getting deeper in Oklahoma, but it also explains why several magnitude-5+ earthquakes struck Oklahoma in 2016, when injection rates were decreasing state wide.

"One fascinating aspect of our study is that sinking wastewater plumes do not require pumping to migrate deeper underground," said Pollyea, "in fact, they'll continue sinking under their own weight for decades after injections cease, and our study shows that the wastewater doesn't have to be much heavier for this to occur."

In terms of earthquake mitigation and regulatory practices, this study has far-reaching implications: The research team pointed out that high-density brines occur throughout many oil and gas basins in the U.S. But they also argued that using this study in practice requires much more information about the fluids. "This study emphasizes the need for site-specific data and increased sampling," said Brown, because "density differences as a driving factor of near-field pressure transients may also lead to pre-injection mitigation actions."

Pollyea said that his research team is continuing to work on their new theory for the hydrogeologic processes that cause induced earthquakes. "We're really interested to know how our ideas about fluid chemistry affect regionally expansive injection operations in places like Oklahoma and Texas," said Pollyea. "And one of our recent M.S. graduates, Graydon Konzen (a study co-author), has done some exciting new work in this area."

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In addition to Konzen and Jayne, Pollyea's team included Virginia Tech Ph.D. candidate Hao Wu, along with Department of Geosciences undergraduate students Cameron R. Chambers and Jordan A. Pritchard, both of whom received their bachelor's degrees in May 2020.

Funding for this study came from the United States Geological Survey, Earthquake Hazards Program.

Disclaimer: The views and conclusions contained in this study are those of the authors and should not be interpreted as representing the opinions or polices of the U.S. Geological Survey. Mention of trade names or commercial products does not constitute endorsement by the U.S. Geological Survey.

Research explores the impacts of mobile phones for Maasai women

VIRGINIA TECH

 

IMAGE: RESEARCHERS CONDUCT A GROUP INTERVIEW ABOUT MOBILE PHONE USE AND EMPOWERMENT WITH MAASAI WOMEN IN NORTHERN TANZANIA IN 2018. STANDING, LEFT TO RIGHT: RESEARCH ASSISTANT FELISTA TERTA, LEAD RESEARCHER KELLY... view more 

CREDIT: VIRGINIA TECH

Mobile phones have the power to change the lives of women living in remote communities by reducing barriers to information and increasing access to local economies. However, the introduction of new technologies can hamper efforts to empower women by increasing disparities in power dynamics.

Video:https://www.youtube.com/watch?time_continue=1&v=YOgYpR5cb5w&feature=emb_logo

Associate Professor Timothy Baird of the College of Natural Resources and Environment and Kelly Summers, who earned a master's degree in geography from Virginia Tech in 2019, led a National Science Foundation-funded study examining the impact that mobile phones are having in Maasai communities in Tanzania. Their findings, published in the Journal of Rural Studies, reveal crucial insights into the ways that technology impacts social dynamics in a distinct community in Africa.

A nomadic people adapt to a changing world

The Maasai are an ethnic group of approximately 2 million people, living primarily in Kenya and Tanzania. As one of a number of indigenous groups in Africa to practice pastoralism, which involves the rearing of livestock, the Maasai have traditionally been nomadic, traversing the continent's Great Rift Valley to find grazing land for their animals.

This way of life, which has sustained Maasai for centuries, is evolving rapidly with the widespread expansion of western society and the ideas and technologies that come with it.

"Maasai are moving into a world some might call 'modern,'" noted Baird, a faculty member in the Department of Geography who has been researching Maasai communities since 2005. "Already there are aspects of our own 'western' lives that are evident in their lives. For example, several developments in Maasai society, from the growth of formal education to the spread of organized religion, have led to changes in the traditional structures that shape Maasai lives. From my vantage, mobile phones have been a kind of steroid for accelerating those changes."

For a population that herds livestock across wide stretches of wild savanna, mobile phones are a boon to their economy and life. But few studies have investigated how this new technology is impacting the lives of women in Maasai communities, which are traditionally patriarchal. In family units where men exert significant control, often over multiple wives, it is important to understand how phones have impacted gender dynamics.

"As a man, it's difficult -- and really not appropriate -- for me to have meetings with individual women or groups of women," Baird explained. "Maasai men may be quite uncomfortable with such a setup, and Maasai women may have no experience engaging with a man who is not a relative. So I needed help."

Enter Kelly Summers, who received bachelor's degrees in natural resources conservation and in forestry from Virginia Tech in 2014.

"While I was serving as an agriculture Extension agent with the Peace Corps in Tanzania, I read an article about Tim's research and reached out to him about doing graduate work in Tanzania," said Summers, who is currently working as an environmental protection specialist for the U.S. Environmental Protection Agency. "Because I had experience interacting with women while living in and traveling to remote communities in Tanzania, it was a good fit."

Summers, working with collaborators, including Maria Elisa Christie, director of women and gender in international development for Virginia Tech's Center for International Research, Education, and Development, was able to conduct interviews with Maasai women, trying to puzzle out the difficult question of what women's empowerment might look like in a cultural context bounded by traditions but also stimulated by an expanding world.

"I don't want to paint a monolithic picture of a whole group of people," Summers said. "All of the women I spoke with had multiple identities within their communities: some women owned businesses, and some took on the work of tending to livestock. They were mothers and wives. Some were teachers and some were active in churches. There are a range of identities, and phones impact those identities for better or worse, or both."

Understanding the contexts of empowerment

To understand how a new technology like mobile phones could potentially support women's empowerment, it was important for researchers to understand what empowerment would look like within the specific contexts of Maasai life.

"To unpack this idea of empowerment, we had to characterize our terms and then look for examples of those characterizations," Baird said. "We had to ask: what are the aspects of your social world, what are the physical materials, and what are your own personal assets that allow you to make decisions and then act on those decisions. From that, we could develop more targeted questions about issues that embody empowerment and the factors that promote or obstruct it."

For Maasai women, the barriers to using mobile phones to gain empowerment vary: from access to reliable electricity to technological fluency and literacy, to having the financial resources to pay for data, their ability to use phones is shaped by a broad array of issues that are themselves in a state of radical flux. The study results show that some concerns are unique to Maasai communities, while others seem universal.

"One observation we made was that Maasai women are very much addicted to their phones," Summers explained. "If they can't get a charge or they can't purchase minutes, the feeling they have is very similar to our own anxiety when our phones lose power. We all want to communicate, we all want to be in a community, and phones are becoming a major tool to do that among Maasai women. Those who don't have access to a phone very much feel that they're missing out."

To work around some of the challenges pertaining to access, Maasai women have found cooperative solutions. Baird and Summers cite the important role that informal village community banks play in allowing women to develop business relationships with other women outside their family units, increasing the women's economic autonomy.

While mobile phones are a positive motivator in seeking these burgeoning opportunities, the authors stressed that mobile phones can also reinforce inequalities. For Maasai women, who typically have multiple roles within family and community structures, mobile phones can simultaneously empower an individual in one role while disempowering her in another.

"The same power dynamics that already existed are now playing out with phones," Baird said. "We found that men, the traditional gatekeepers in this society, are the ones who often control women's phones. They can use them as a reward or a punishment, a carrot or a stick."

Summers added that one of their findings is that Maasai men and women used phones differently: "Men will use their phones to talk to people outside their immediate social circle, but women will primarily talk to people they already know: mothers and sisters and other people in their family unit. They are rarely using their phones to reach out to new people."

While mobile phones can be used in ways that empower women, the researchers stress that it is more realistic to view this technology as a new arena where tensions between traditional cultural norms and the growing aspirations to engage in a broadly interconnected world continue to play out. Future efforts aimed at using mobile technologies to advance women's empowerment need to better understand what empowerment would look like within the specific contexts of a distinct culture, and what consequences -- positive and negative -- are risked when new technologies take root.

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What will our cities look like after COVID-19?

UNIVERSITY OF BRITISH COLUMBIA

 

IMAGE: UBC URBAN PLANNING LECTURER ERICK VILLAGOMEZ view more 

CREDIT: UBC

The past few months have been a highly unusual time as people sheltered in place to prevent the spread of COVID-19. Schools, streets and stadiums fell silent, tourist hot spots became ghost towns, and sidewalk traffic largely consisted of grocery and food deliveries.

In an article published this week in Cities & Health, UBC planning experts Jordi Honey-Rosés and Erick Villagomez analyzed the implications of these changes on city planning and space design. Alongside other scholars from Chile, China, Mexico, India and Spain, they looked at the measures taken by major cities to cope with the pandemic, and how those efforts transformed and continue to transform urban life.

The researchers say the pandemic is transforming city building, design, energy flows, mobility patterns, housing preferences, green spaces and transportation systems. Many of these changes may be temporary, while others may be permanent.

"In some cases, cities are accelerating the implementation of changes they had in the works already, such as rolling out planned bicycle infrastructure, street calming projects or sidewalk re-designs. In other cases, planners and neighbours are making things up as they go along, experimenting, testing and relying on low-cost interventions," said Honey-Rosés, an associate professor in the School of Community and Regional Planning at UBC.

Erick Villagomez, a part-time lecturer at the school, noted the drop in pedestrian traffic associated with commercial activity during COVID-19. According to the most recent Google Mobility Report, mobility associated with retail and recreation across Canada still sits at about 17 per cent below January-February median levels.

"Although this rate continues to rise slowly, the reduced pedestrian traffic to-date has already had strong effects on many local businesses, many of which have had to close their doors indefinitely. This trend will likely continue until a viable solution to the pandemic is found," said Villagomez.

Over the longer term, the researchers see further changes taking place, with cities likely looking to implement low-cost and temporary street calming and pedestrianization projects. "Streets might need to be re-designed. With online shopping and home food delivery having taken off, there is huge demand for curbside street parking, not only to meet new delivery needs, but also to free space for pedestrians," said Honey-Rosés.

They add that the look and feel of cities that rely on tourism will change, both in negative and positive ways. Businesses may continue to struggle, but there is an increased interest in building a stronger pedestrian-friendly environment. In Toronto, for example, the City accelerated plans to install cycling infrastructure along the popular Danforth Avenue as a part of COVID-19 relief plans.

As well, there is now a greater appreciation of the importance of providing easily accessible opportunities for the enjoyment of nature and a diversity of recreation activities. Cities may revisit the potential of unused spaces such as brownfield sites and building rooftops, citing the staggering amount of rooftops that are underused in many cities and could be converted into rooftop gardens.

Over time, the researchers say our sense of place and space may be permanently transformed. "Public space might still be a place for social interaction, but it may be more difficult for the spontaneous and informal. The pandemic may limit our ability to develop new relationships, especially among strangers," said Honey-Rosés.

On the positive side, the pandemic has given us an unprecedented opportunity to examine the links between urban planning, public space and wellbeing, he added. "Our future city is not preordained, but will be the result of specific decisions about public space. We hope citizens will talk to their leaders and come together with planning and policy professionals to build healthier cities during this crisis and beyond."

Villagomez, who has written extensively about the implications of transforming cities to meet the standard six-foot social distancing protocols, notes that the everyday spaces we inhabit have been shaped by millennia based on dimensions that are much smaller--three to four feet being the most common.

"Right now, people are attempting to adapt systems, behaviours and built spaces based on three-to-four-foot distances to the larger social-distancing dimensions. The results have been very interesting, showing a lot of creativity and innovation. But it's also already evident that cities cannot and will not fully change in every respect to allow six-foot distancing. This will continue to evolve as restrictions change," Villagomez added.

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"The impact of COVID-19 on public space: an early review of the emerging questions - design, perceptions and inequities" was published in Cities & Health and can be accessed at https://www.tandfonline.com/doi/full/10.1080/23748834.2020.1780074