197 research outputs found
Effect of salicylic acid treatment on cadmium toxicity and leaf lipid composition in sunflower
The ameliorative effect of salicylic acid (SA) on cadmium (Cd) toxicity in sunflower plants was studied by investigating plant growth and fatty acid composition. Sunflower plants in two leaves stage were exposed to CdCl2 treatment (0, 50, 100, 150 and 200 µM) and then were treated with salicylic acid (0, 250 and 500 µM) as foliage spraying. One week after the last salicylic acid treatment,plants were harvested and growth parameters were measured . Oil of leaf was extracted in a Soxhlet system and fatty acid composition were measured by gas chromatography (GC). Statistical analyses showed excess Cd reduced growth parameters (fresh weight and length of stems and roots, fresh weight and number of leaves)and SA increased them compared with the control. Maximum reduction in these parameters was at 200 µmol Cd and 0µmol of SA. Cd caused a shift in fatty acids composition, resulting in a lower degree of their unsaturation and an increase in saturated fatty acids in sunflower leaves,whereas SA improved them. SA, particularly increased the percentage of linolenic acid and lowered that of palmitic acid by the same proportion. These results sugg membrane integrity due to lipids est that SA could be used as a potential growth regulator and a stabilizer ofprotection of cadmium-induced oxidative stress to improve plant resistance to Cd stres
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Characterization of shock waves in power ultrasound
© The Author(s), 2021. The application of cavitation-induced shock waves generated at low driving frequencies, known as power ultrasound, is essential for a wide range of fields, such as sonochemistry, lithotripsy, nanomaterials, emulsions and casting, to name but a few. In this paper, we present measurements of the shock wave pressures emitted by cavitating bubbles in water, under ultrasonic excitation produced by an immersed probe oscillating at 24 kHz. A broad-spectrum fibre-optic hydrophone calibrated in the range of 1–30 MHz was used for this purpose. Spectral analysis of the data reveals a consistent resonance peak at a very narrow range of frequencies (3.27–3.43 MHz). Results were confirmed using real-time analysis of high-speed recordings. By eliminating other possible sources, we propose that this new peak might be associated with shock wave emissions from collapsing bubbles. Spatial maps obtained by collating individual shock wave pressures highlight the effect of pressure shielding with increasing input power, attributed to a cloud of bubbles surrounding the probe. This work contributes towards the elucidation of the key properties of cavitation-driven shock waves and the underlying mechanisms, essential in controlling the effectiveness of the external processing conditions on various physical, chemical and biological systems.UK Engineering and Physical Sciences Research Council (EPSRC) through the UltraMelt2 (grants EP/R011001/1, EP/R011095/1 and EP/R011044/1) and EcoUltra2D (grants EP/R031401/1, EP/R031665/1, EP/R031819/1 and EP/R031975/1) projects
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Scale Up Design Study on Process Vessel Dimensions for Ultrasonic Processing of Water and Liquid Aluminium
UK Engineering and Physical Sciences Research Council (EPSRC) through the UltraMelt2 (grant EP/R011001/1, EP/R011095/1 and EP/R011044/1) and EcoUltra2D (grant EP/R031401/1, EP/R031665/1, EP/R031819/1, EP/ R031975/1) projects
Yoongoorrookoo
Since the momentous release of the Montecristi Constitution of
Ecuador in 2008, which recognised Nature, or Pacha Mama, as a
subject of rights, the rights of Nature movement across the world
has gained exponential momentum, with numerous jurisdictions
worldwide now recognising some form of legal subjectivity vested
upon Nature. In particular, since 2017, river personhood has
dominated news headlines around the world as one of the most
recognisable forms of Nature’s novel subjectivity. The emergence
of legal personhood for nature, however, has been far from
uncontroversial, and numerous critiques have been advanced
against the use of such a legal category – traditionally applied to
humans and their abstract creations (such as States and
corporations) – to the natural world, resulting in numerous calls for
an alternative category of legal personhood (one that some rights
of Nature advocates have termed an ‘environmental person’).
Against the backdrop of this emerging debate, this paper
acknowledges the work undertaken by the Martuwarra Fitzroy
River Council (Martuwarra Council), which was established in 2018
in the Kimberley region of Western Australia by six independent
Indigenous nations to preserve, promote and protect their
ancestral River from ongoing destructive ‘development’. The
Council believes it is time to recognise the pre-existing and
continuing legal authority of Indigenous law, or ‘First Law’, in
relation to the River, in order to preserve its integrity through a
process of legal decolonisation. First Law differs markedly from its
colonial counterpart, as its principles are not articulated in terms of
rules, policies and procedures, but rather through stories. This
paper, therefore, begins with a dialogical translation of one First
Law story relating to Yoongoorrookoo,1 the ancestral serpent being,2 to create a semantic bridge between two apparently distant
legal worldviews. A dialogical comparative analysis is then followed
to posit and explore the concept of an ‘ancestral person’ as a novel
comparative tool that may be able not only to capture the idea of
Nature as a legal subject, but also complex Indigenous worldviews
that see Nature – in this case instantiated in the Martuwarra – as
an ancestral being enmeshed in a relationship of interdependence
and guardianship between the human and the nonhuman world.
To instantiate and embody such relationships, the paper directly,
and somewhat provocatively, acknowledges the River itself, the
Martuwarra RiverOfLife, as the primary participant in such dialogue,
an embodied non-human co-author who began a conversation
then left to human writers to continue
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An eco-friendly solution for liquid phase exfoliation of graphite under optimised ultrasonication conditions
Data availability: The data that supports the findings of this study are available upon request from the corresponding author.Appendix A. Supplementary data: available online at: https://www.sciencedirect.com/science/article/pii/S0008622322011125?via%3Dihub#appsec1 .Copyright © 2023 The Authors. Ultrasonic assisted liquid phase exfoliation (ULPE) is a promising method for the large scale production of 2D materials. Currently, toxic solvents such as N-Methyl-2-pyrrolidone (NMP) are commonly used for the production of graphene. In this paper four solvents; three green solvents (water, ethanol and water/ethanol) plus NMP for comparison, were sonicated and examined in terms of their bubble dynamics and acoustic emissions. Advanced fundamental analysis was conducted using high-speed imaging synchronised with acoustic pressure measurements complemented by shadowgraphic photography of the emitted shockwaves, in order to determine a suitable eco-friendly solvent medium from a cavitation bubbles dynamics perspective. Thereafter, ULPE of graphite in the optimum solvent took place for 2 h under controlled ultrasonication parameters. The produced graphene samples were characterised by employing a series of techniques consisting of Ultraviolet–visible (UV–Vis) and Raman spectroscopy as well as transmission electron microscopy (TEM). A mixture of deionised water and ethanol was shown to produce a yield twice that of pure water, comprising of high quality few layer graphene (3–5 Ls) with an average area of ∼1.15 (μm)2 and stability of ∼78% for the duration of six months. This combination is a promising eco-friendly substitute for future commercial manufacturing of graphene.UK Engineering and Physical Sciences Research Council (EPSRC), to the project “Sustainable and industrially scalable ultrasonic liquid phase exfoliation technologies for manufacturing 2D advanced functional materials” (EcoUltra2D), with the grant nos. EP/R031665/1; EP/R031401/1; EP/R031819/1; EP/R031975/1
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Dual frequency ultrasonic cavitation in various liquids: High-speed imaging and acoustic pressure measurements
Data Availability: The data that support the findings of this study are available from the corresponding authors upon reasonable request.Supplementary material: See the supplementary material (https://www.scitation.org/doi/suppl/10.1063/5.0136469) for additional data acquisition, bubble dynamics calculations, and physical properties of investigated liquids.Copyright © 2023 Author(s). . Ultrasonic cavitation is used in various processes and applications, utilizing powerful shock waves and high-speed liquid jets generated by the collapsing bubbles. Typically, a single frequency source is used to produce the desired effects. However, optimization of the efficiency of ultrasound reactors is necessary to improve cavitation activity in specific applications such as for the exfoliation of two dimensional materials. This research takes the next step to investigate the effect of a dual frequency transducer system on the bubble dynamics, cavitation zone, pressure fields, acoustic spectra, and induced shock waves for four liquids with a range of physical properties. Using ultra-high-speed imaging and synchronized acoustic pressure measurements, the effect of ultrasonic dual frequencies on bubble dynamics was investigated. The addition of a high frequency transducer (1174 kHz) showed that the bubble fragments and satellite bubbles induced from a low frequency transducer (24 kHz) were able to extend their lifecycle and increase spatial distribution, thus, extending the boundaries of the cavitation zone. Furthermore, this combination of ultrasonic frequencies generated higher acoustic pressures (up to 180%) and enhanced the characteristic shock wave peak, indicating more bubble collapses and the generation of additional shock waves. The dual frequency system also enlarged the cavitation cloud size under the sonotrode. These observations specifically delineated the enhancement of cavitation activity using a dual frequency system pivotal for optimization of existing cavitation-based processing technologies.UK Engineering and Physical Sciences Research Council (EPSRC) to the project “Sustainable and industrially scalable ultrasonic liquid phase exfoliation technologies for manufacturing 2D advanced functional materials” (EcoUltra2D) with the Grant Nos. EP/R031665/1, EP/R031401/1, EP/R031819/1, and EP/R031975/1
Mechanical design and development of TES bolometer detector arrays for the Advanced ACTPol experiment
The next generation Advanced ACTPol (AdvACT) experiment is currently underway
and will consist of four Transition Edge Sensor (TES) bolometer arrays, with
three operating together, totaling ~5800 detectors on the sky. Building on
experience gained with the ACTPol detector arrays, AdvACT will utilize various
new technologies, including 150mm detector wafers equipped with multichroic
pixels, allowing for a more densely packed focal plane. Each set of detectors
includes a feedhorn array of stacked silicon wafers which form a spline profile
leading to each pixel. This is then followed by a waveguide interface plate,
detector wafer, back short cavity plate, and backshort cap. Each array is
housed in a custom designed structure manufactured from high purity copper and
then gold plated. In addition to the detector array assembly, the array package
also encloses cryogenic readout electronics. We present the full mechanical
design of the AdvACT high frequency (HF) detector array package along with a
detailed look at the detector array stack assemblies. This experiment will also
make use of extensive hardware and software previously developed for ACT, which
will be modified to incorporate the new AdvACT instruments. Therefore, we
discuss the integration of all AdvACT arrays with pre-existing ACTPol
infrastructure.Comment: 9 pages, 5 figures, SPIE Astronomical Telescopes and Instrumentation
conference proceeding
Cyber-physical energy systems modeling, test specification, and co-simulation based testing
The gradual deployment of intelligent and coordinated devices in the electrical power system needs careful investigation of the interactions between the various domains involved. Especially due to the coupling between ICT and power systems a holistic approach for testing and validating is required. Taking existing (quasi-) standardised smart grid system and test specification methods as a starting point, we are developing a holistic testing and validation approach that allows a very flexible way of assessing the system level aspects by various types of experiments (including virtual, real, and mixed lab settings). This paper describes the formal holistic test case specification method and applies it to a particular co-simulation experimental setup. The various building blocks of such a simulation (i.e., FMI, mosaik, domain-specific simulation federates) are covered in more detail. The presented method addresses most modeling and specification challenges in cyber-physical energy systems and is extensible for future additions such as uncertainty quantification
Topical Gene Electrotransfer to the Epidermis of Hairless Guinea Pig by Non-invasive Multielectrode Array
Topical gene delivery to the epidermis has the potential to be an effective therapy for skin disorders, cutaneous cancers, vaccinations and systemic metabolic diseases. Previously, we reported on a non-invasive multielectrode array (MEA) that efficiently delivered plasmid DNA and enhanced expression to the skin of several animal models by in vivo gene electrotransfer. Here, we characterized plasmid DNA delivery with the MEA in a hairless guinea pig model, which has a similar histology and structure to human skin. Significant elevation of gene expression up to 4 logs was achieved with intradermal DNA administration followed by topical non-invasive skin gene electrotransfer. This delivery produced gene expression in the skin of hairless guinea pig up to 12 to 15 days. Gene expression was observed exclusively in the epidermis. Skin gene electrotransfer with the MEA resulted in only minimal and mild skin changes. A low level of human Factor IX was detected in the plasma of hairless guinea pig after geneelectrotransfer with the MEA, although a significant increase of Factor IX was obtained in the skin of animals. These results suggest geneelectrotransfer with the MEA can be a safe, efficient, non-invasive skin delivery method for skin disorders, vaccinations and potential systemic diseases where low levels of gene products are sufficient
An Integrated Research Infrastructure for Validating Cyber-Physical Energy Systems
Renewables are key enablers in the plight to reduce greenhouse gas emissions
and cope with anthropogenic global warming. The intermittent nature and limited
storage capabilities of renewables culminate in new challenges that power
system operators have to deal with in order to regulate power quality and
ensure security of supply. At the same time, the increased availability of
advanced automation and communication technologies provides new opportunities
for the derivation of intelligent solutions to tackle the challenges. Previous
work has shown various new methods of operating highly interconnected power
grids, and their corresponding components, in a more effective way. As a
consequence of these developments, the traditional power system is being
transformed into a cyber-physical energy system, a smart grid. Previous and
ongoing research have tended to mainly focus on how specific aspects of smart
grids can be validated, but until there exists no integrated approach for the
analysis and evaluation of complex cyber-physical systems configurations. This
paper introduces integrated research infrastructure that provides methods and
tools for validating smart grid systems in a holistic, cyber-physical manner.
The corresponding concepts are currently being developed further in the
European project ERIGrid.Comment: 8th International Conference on Industrial Applications of Holonic
and Multi-Agent Systems (HoloMAS 2017
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