The present study is based on a multidisciplinary approach carried out for the first time on
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, two varieties from the endemic and endangered medicinal species listed in the IUCN red ...list,
(L.) Link. Therefore, morphological, phytochemical, and genetic characterisations were carried out in the present work. Morphological characterisation was established based on 23 qualitative and quantitative characters describing the vegetative and floral parts. The phytochemical compounds were determined by UHPLC. Genetic characterisation of extracted DNA was subjected to PCR using two sets of universal primers, rbcL a-f/rbcL a-R and rpocL1-2/rpocL1-4, followed by sequencing analysis using the Sanger method. The results revealed a significant difference between the two varieties studied. Furthermore, phytochemical analysis of the studied extracts revealed a quantitative and qualitative variation in the chemical profile, as well as the presence of interesting compounds, including new compounds that have never been reported in
. The phylogenetic analysis of the DNA sequences indicated a similarity percentage of 91%. Based on the morphological characterisation and congruence with the phytochemical characterisation and molecular data, we can confirm that
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represent two different taxa.
The surface integrity of machined metal components is critical to their in-service functionality, longevity and overall performance. Surface defects induced by machining operations vary from the nano ...to macro scale, which cause microstructural, mechanical and chemical effects. Hence, they require advanced evaluation and post processing techniques. While surface integrity varies significantly across the range of machining processes, this paper explores the state-of-the-art of surface integrity research with an emphasis on their governing mechanisms and emerging evaluation approaches. In this review, removal mechanisms are grouped by their primary energy transfer mechanisms; mechanical, thermal and chemical based. Accordingly, the resultant multi-scale phenomena associated with metal machining are analyzed. The contribution of these material removal mechanisms to the workpiece surfaces/subsurface characteristics is reviewed. Post-processing options for the mitigation of induced surface defects are also discussed.
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•Machining-induced surface integrity significantly influences the in-service functional performance of advanced alloys.•Surface integrity is affected by the energy transfer mechanism, i.e. mechanical, thermal, chemical and their combination.•State-of-the-art research of surface integrity is discussed, with emphasis on emerging approaches for its evaluation.•Influence of different material removal mechanisms upon the workpiece surface/subsurface characteristics are explored.
•Comprehensive exploration and critique of aerogels as promising CO2-capture materials.•Perspectives on aerogels’ tunable surface chemistry and proper textural properties.•Focus on characterisation, ...process economics and performance.•Detailed outlook towards prospects for future CO2-capture deployment.
Recently, greenhouse gases - especially CO2 – have been released into the atmosphere in ever-increasing quantities through activities such as industrial emission and combustion. Owing to their high absorption capacities, they appear to be implicated causatively in observed increases in surface temperature and global climate changes. Between porous solid sorbents, aerogels have recently been considered as promising adsorbents for CO2 capture due to their tunable surface chemistry and proper textural properties. Currently, a variety of different aerogels are being developed at laboratory scale, and some of them have been taken to pilot production. In order to explore the commercialisation-feasibility of aerogels as CO2 capture adsorbents, more research needs to be done on low-cost materials and production processes, with low or controlled sorption of water as well as a good thermal regeneration capacity. In this review paper, different aspects of scientific investigations on CO2-sorption applications of aerogels have been studied. The review contains seven main sections: preparation, characterisation, modification of aerogels, literature studies on CO2-sorption performances, kinetic and thermodynamic models on CO2 adsorption, important factors on CO2 capture and outlook for future perspectives.
Laser scanning is an efficient approach for collecting rock mass point cloud scans to characterise structural discontinuities. However, developing computationally efficient and robust analytical ...workflows remains an open research problem. Existing semi-automated and automated approaches rely on point normals which are prone to mapping error when high variability exists in the local-support region. This study proposes a new automated algorithm that uses the spatial distribution of points on discontinuities to capture unique signatures in the form of sinusoidal waves. The discontinuities are then effectively characterised by clustering the amplitude and phase profiles of the sinusoidal waves. The presented amplitude and phase decomposition (APD) approach requires minimal pre-processing. Moreover, it can be applied directly to raw point clouds as filtering is inherently included through the fast Fourier transform (FFT) based decomposition of the signals. The method was evaluated on an underground tunnel dataset with exposed structural discontinuity planes. The efficacy of the developed approach was tested against manual segmentation using virtual compass plugin in open-source software (Cloud Compare), semi-automated open-source (discontinuity set extractor) and proprietary (Maptek PointStudio) software, and other automated algorithmic approaches based on point normal clustering and region growing. The APD approach produced the least error in estimating mean discontinuity dip angle and dip direction which was ±1.15° and ±1.39° with a dispersion error of ±2.24° and ±1.54°, respectively.
Oppositely charged polymer-surfactant systems are expected to interact with formation of coacervate complexes near composition of charge-neutrality. Such behaviour is widely used in formulated ...products (e.g. household and personal care), where the co-deposition of coacervates and active ingredients on various surfaces is triggered by dilution. A transition towards the use of more sustainable ingredients is currently ongoing as a response to the need of more environmentally conscious choices in production, albeit slowed down by the often more complex and not fully understood bulk and interfacial behaviour of new ingredients. In this work, mixtures of a medium-chain fatty acid (sodium decanoate) and two grades of bio-based cationic modified inulin were studied. The phase behaviour was determined in a wide composition matrix. The formation of coacervate complexes was observed for the mixture with the higher charge density polymer at a surfactant concentration of 1–3 wt%, close to the surfactant critical micellar concentration in pure water. Such behaviour was confirmed by DLS and SAXS data, suggesting surfactant-polymer complexation in a concentrated phase of packed micelles with a micelle-to-micelle distance of ∼4.5 nm. In situ ellipsometry and neutron reflectometry experiments were conducted to study the effect on surface deposition when diluting. The ellipsometry showed an adsorbed mass of ∼1.3–1.9 mg/m2, consistent with the deposition of a coacervate layer, and considerably higher than the neat, adsorbed polymer layer of ∼0.3 mg/m2. In the case of the neutron reflectometry experiments, dilution was performed before contact with the surface (pre-mixing), and no adsorption of coacervates was observed, but rather the adsorption of a polymer layer (0.49–0.85 mg/m2). The different results obtained with the different techniques highlight the kinetic nature of bulk coacervate formation and deposition, and the competition between these two phenomena. Maximal deposition can be achieved if one can control this time window either by tuning the composition of the system or the experimental set-up, to mimic the conditions of a specific application.
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The adsorption mechanisms of lead (Pb2+) on four biochars (SB produced from British hardwood at 600°C and three standard biochars produced from wheat straw pellets at 700°C (WSP700), rice husk at ...700°C (RH700) and soft wood pellets at 550°C (SWP550)) were characterised qualitatively and quantitatively, using a combination of chemical and micro-structural methods. Sequential extraction test results show that Pb2+ was predominantly adsorbed on SB (85.31%), WSP700 (75.61%) and RH700 (85.76%) as acidic soluble fraction, which was potentially bioavailable if applied in soil. The exchangeable fraction for SB, WSP700 and RH700 was low (1.38–4.29%) and their water soluble fraction was negligible (0–0.14%). Micro-structural analysis further investigated this fraction and confirmed the presence of cerussite (PbCO3) on SB and hydrocerussite (Pb3(CO3)2(OH)2) on WSP700, RH 700 and SWP550, suggesting a mechanism of surface precipitation for Pb2+ adsorption on the biochars. The percentages of Pb2+ in the form of PbCO3 on SB (82.24%) and Pb3(CO3)2(OH)2 on WSP700 (13.00%), RH 700 (19.19%) and SWP550 (29.70%) were quantified using thermogravimetric analysis (TGA). This study suggests that it is feasible to quantify different adsorption mechanisms of Pb2+ on biochars, which is important for the practical application of biochar in water and/or soil treatment.
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•Pb2+ mainly exists as acid soluble fraction (75.61–85.76%) on SB, WSP700 and RH700.•82.24% of total adsorbed Pb2+ exists as cerussite on SB.•13.00–29.70% of total adsorbed Pb2+ exists as hydrocerussite on rest three biochars.•The rest acidic soluble fraction for Pb2+ is likely adsorbed through cation-π interaction.•Using chemical and micro-structural methods to quantify adsorption mechanisms is feasible.
Choosing a suitable sample size in qualitative research is an area of conceptual debate and practical uncertainty. That sample size principles, guidelines and tools have been developed to enable ...researchers to set, and justify the acceptability of, their sample size is an indication that the issue constitutes an important marker of the quality of qualitative research. Nevertheless, research shows that sample size sufficiency reporting is often poor, if not absent, across a range of disciplinary fields.
A systematic analysis of single-interview-per-participant designs within three health-related journals from the disciplines of psychology, sociology and medicine, over a 15-year period, was conducted to examine whether and how sample sizes were justified and how sample size was characterised and discussed by authors. Data pertinent to sample size were extracted and analysed using qualitative and quantitative analytic techniques.
Our findings demonstrate that provision of sample size justifications in qualitative health research is limited; is not contingent on the number of interviews; and relates to the journal of publication. Defence of sample size was most frequently supported across all three journals with reference to the principle of saturation and to pragmatic considerations. Qualitative sample sizes were predominantly - and often without justification - characterised as insufficient (i.e., 'small') and discussed in the context of study limitations. Sample size insufficiency was seen to threaten the validity and generalizability of studies' results, with the latter being frequently conceived in nomothetic terms.
We recommend, firstly, that qualitative health researchers be more transparent about evaluations of their sample size sufficiency, situating these within broader and more encompassing assessments of data adequacy. Secondly, we invite researchers critically to consider how saturation parameters found in prior methodological studies and sample size community norms might best inform, and apply to, their own project and encourage that data adequacy is best appraised with reference to features that are intrinsic to the study at hand. Finally, those reviewing papers have a vital role in supporting and encouraging transparent study-specific reporting.
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