35 research outputs found
Preliminary crystallographic studies of an extremely thermostable KDG aldolase from Sulfolobus solfataricus
The 2023 terahertz science and technology roadmap
Terahertz (THz) radiation encompasses a wide spectral range within the electromagnetic spectrum that extends from microwaves to the far infrared (100 GHz-∼30 THz). Within its frequency boundaries exist a broad variety of scientific disciplines that have presented, and continue to present, technical challenges to researchers. During the past 50 years, for instance, the demands of the scientific community have substantially evolved and with a need for advanced instrumentation to support radio astronomy, Earth observation, weather forecasting, security imaging, telecommunications, non-destructive device testing and much more. Furthermore, applications have required an emergence of technology from the laboratory environment to production-scale supply and in-the-field deployments ranging from harsh ground-based locations to deep space. In addressing these requirements, the research and development community has advanced related technology and bridged the transition between electronics and photonics that high frequency operation demands. The multidisciplinary nature of THz work was our stimulus for creating the 2017 THz Science and Technology Roadmap (Dhillon et al 2017 J. Phys. D: Appl. Phys. 50 043001). As one might envisage, though, there remains much to explore both scientifically and technically and the field has continued to develop and expand rapidly. It is timely, therefore, to revise our previous roadmap and in this 2023 version we both provide an update on key developments in established technical areas that have important scientific and public benefit, and highlight new and emerging areas that show particular promise. The developments that we describe thus span from fundamental scientific research, such as THz astronomy and the emergent area of THz quantum optics, to highly applied and commercially and societally impactful subjects that include 6G THz communications, medical imaging, and climate monitoring and prediction. Our Roadmap vision draws upon the expertise and perspective of multiple international specialists that together provide an overview of past developments and the likely challenges facing the field of THz science and technology in future decades. The document is written in a form that is accessible to policy makers who wish to gain an overview of the current state of the THz art, and for the non-specialist and curious who wish to understand available technology and challenges. A such, our experts deliver a ‘snapshot’ introduction to the current status of the field and provide suggestions for exciting future technical development directions. Ultimately, we intend the Roadmap to portray the advantages and benefits of the THz domain and to stimulate further exploration of the field in support of scientific research and commercial realisation
The 2023 terahertz science and technology roadmap
Terahertz (THz) radiation encompasses a wide spectral range within the electromagnetic spectrum that extends from microwaves to the far infrared (100 GHz–∼30 THz). Within its frequency boundaries exist a broad variety of scientific disciplines that have presented, and continue to present, technical challenges to researchers. During the past 50 years, for instance, the demands of the scientific community have substantially evolved and with a need for advanced instrumentation to support radio astronomy, Earth observation, weather forecasting, security imaging, telecommunications, non-destructive device testing and much more. Furthermore, applications have required an emergence of technology from the laboratory environment to production-scale supply and in-the-field deployments ranging from harsh ground-based locations to deep space. In addressing these requirements, the research and development community has advanced related technology and bridged the transition between electronics and photonics that high frequency operation demands. The multidisciplinary nature of THz work was our stimulus for creating the 2017 THz Science and Technology Roadmap (Dhillon et al 2017 J. Phys. D: Appl. Phys. 50 043001). As one might envisage, though, there remains much to explore both scientifically and technically and the field has continued to develop and expand rapidly. It is timely, therefore, to revise our previous roadmap and in this 2023 version we both provide an update on key developments in established technical areas that have important scientific and public benefit, and highlight new and emerging areas that show particular promise. The developments that we describe thus span from fundamental scientific research, such as THz astronomy and the emergent area of THz quantum optics, to highly applied and commercially and societally impactful subjects that include 6G THz communications, medical imaging, and climate monitoring and prediction. Our Roadmap vision draws upon the expertise and perspective of multiple international specialists that together provide an overview of past developments and the likely challenges facing the field of THz science and technology in future decades. The document is written in a form that is accessible to policy makers who wish to gain an overview of the current state of the THz art, and for the non-specialist and curious who wish to understand available technology and challenges. A such, our experts deliver a 'snapshot' introduction to the current status of the field and provide suggestions for exciting future technical development directions. Ultimately, we intend the Roadmap to portray the advantages and benefits of the THz domain and to stimulate further exploration of the field in support of scientific research and commercial realisation
Assessing and communicating risk with communities living on contaminated land.
The U.K. government has emphasized redeveloping derelict land for housing. As a result, tools for assessing brownfield sites are well developed. However, there are many potentially contaminated sites on which people live, often not to the people's knowledge. For these situations, statutory guidance for risk communication is underdeveloped and, in certain situations, inadequate. This paper illustrates limitations of current methods using a heavily populated site where levels of specific contaminants exceed statutory limits. The authors describe how residents were involved in the site assessment process and how the process may be improved, and propose a framework to incorporate risk communication into the contaminated-land use strategy
Evaluating fugacity models for trace components in landfill gas.
A fugacity approach was evaluated to reconcile loadings of vinyl chloride
(chloroethene), benzene, 1,3-butadiene and trichloroethylene in waste with
concentrations observed in landfill gas monitoring studies. An evaluative
environment derived from fictitious but realistic properties such as volume,
composition, and temperature, constructed with data from the Brogborough
landfill (UK) test cells was used to test a fugacity approach to generating the
source term for use in landfill gas risk assessment models (e.g. GasSim).
SOILVE, a dynamic Level II model adapted here for landfills, showed greatest
utility for benzene and 1,3-butadiene, modelled under anaerobic conditions over
a 10 year simulation. Modelled concentrations of these components (95 300 μg
m−3; 43 μg m−3) fell within measured ranges observed in gas from landfills (24
300–180 000 μg m−3; 20–70 μg m−3). This study highlights the need (i) for
representative and time-referenced biotransformation data; (ii) to evaluate the
partitioning characteristics of organic matter within waste systems and (iii)
for a better understanding of the role that gas extraction rate (flux) plays in
producing trace component concentration
Identifying source correlation parameters for hydrocarbon wastes using compound- specific isotope analysis.
A preliminary evaluation of compound-specific isotope analysis (CSIA) as a
novel, alternative method for identifying source correlation compounds in soils
contaminated with residual heavy or weathered petroleum wastes is presented.
Oil-contaminated soil microcosms were established using soil (sandy-loam, non-
carbonaceous gley) amended with ballast-, crude- or No.6 fuel oil. Microcosms
were periodically sampled over 256 days and δ13C values (which express the ratio
of 13C to 12C) determined at each time point for five n-alkanes and the
isoprenoid norpristane using gas chromatography–isotope ratio mass spectrometry
(GC-IRMS). Although some temporal variation was observed, no significant
temporal shifts in the δ13C values for the five n-alkanes were measured in all
three oils. Isoprenoid isotope ratios (δ13C) appeared to be least affected by
biotransformation, especially in the No.6 fuel oil. The research suggests that
the δ13C of isoprenoids such as norpristane, may be of use as source correlation
parameters. Compound-specific isotope analysis (CSIA) is a promising method for
identifying source correlation compounds in soils contaminated with heavy or
weathered petroleum
Assessing potential risk of heavy metal exposure from consumption of home-produced vegetables by urban populations
We performed a risk assessment of metal exposure to population subgroups living on, and growing food on, urban sites. We modeled uptake of cadmium, copper, nickel, lead, and zinc for a selection of commonly grown allotment and garden vegetables. Generalized linear cross-validation showed that final predictions of Cd, Cu, Ni, and Zn content of food crops were satisfactory, whereas the Pb uptake models were less robust. We used predicted concentrations of metals in the vegetables to assess the risk of exposure to human populations from homegrown food sources. Risks from other exposure pathways (consumption of commercially produced foodstuffs, dust inhalation, and soil ingestion) were also estimated. These models were applied to a geochemical database of an urban conurbation in the West Midlands, United Kingdom. Risk, defined as a "hazard index," was mapped for three population subgroups: average person, highly exposed person, and the highly exposed infant (assumed to be a 2-year-old child). The results showed that food grown on 92% of the urban area presented minimal risk to the average person subgroup. However, more vulnerable population subgroups (highly exposed person and the highly exposed infant) were subject to hazard index values greater than unity. This study highlights the importance of site-specific risk assessment and the "suitable for use" approach to urban redevelopment
A review of the abundance, behaviour and detection of clostridial pathogens in agricultural soils.
The soil is a reservoir for various clostridial pathogens, with agricultural soils representing a major source of contamination for overlying crops and grazing livestock. Understanding the prevalence and behaviour of pathogens in these soils is fundamental to ascertaining and mitigating the risk of disease from agroecosystems. This article reviews research pertaining to the overall distribution and abundance of clostridial pathogens in the soil while identifying possible environmental and soil factors influencing their behaviour. Large-scale soil screens have identified pathogens across the globe, although some Clostridium botulinum toxinotypes are more prevalent in certain geographic regions. Faecal inputs and organic waste amendments to the soil can elevate the levels of enteric clostridial pathogens in the soil and the subsequent disease risk, as highlighted by case–control studies. The ability of Clostridia to sporulate results in their long-term persistence post-introduction, increasing the time period for disease transmission. Regularly or permanently saturated soils may also enhance survival, or potentially facilitate the regrowth of some indigenous or introduced Clostridia. This is supported by the high prevalence of Clostridia in paddy soils, greater detection of pathogens in flooded soils, and the higher onset of some clostridial diseases in regions with poorly drained soils. Future research should elucidate soil types and environmental conditions which can enhance pathogen survival/regrowth. The adoption of molecular and sequencing technologies for future diagnostics can facilitate more sensitive detection and a higher resolution of pathogen typing, allowing a better understanding of pathogen population dynamics in farm soils and disease epidemiology
Optimising the biopiling of weathered hydrocarbons within a risk management framework.
Thirty years of research into petroleum microbiology and bioremediation have
bypassed an important observation – that many hydrocarbon contaminated sites
posing potential risks to human health harbour weathered, ‘mid-distillate’ or
heavy oils rather than ‘fresh product’ (Pollard, 2003). Ex-situ biopiling is an
important technology for treating soils contaminated with weathered
hydrocarbons. However, its performance continues to be represented by reference
to reductions in the hydrocarbon ‘load’ in the soils being treated, rather than
reductions in the risks posed by the hydrocarbon contamination (Owens and
Bourgouin, 2003; Tien et al., 1999). The absence of ‘risk’ from the vocabulary
of many operators and remediation projects reduces stakeholder (regulatory,
investor, landowner, and public) confidence in remediation technologies, and
subsequently limits the market potential of these technologies. Stakeholder
confidence in the biopiling of weathered hydrocarbons may be improved by
demonstrating process optimisation within a validated risk ma