193 research outputs found

    Catalytic depolymerisation of isolated lignin to fine chemicals: part 2 – process optimisation

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    The depolymerisation of an ammonia treated lignin to alkylphenols over a Pt/alumina catalyst was investigated under a range of process parameters including, pressure, mass of lignin, solvent and gas atmosphere. The depolymerisation was shown to be under kinetic control and orders of reaction in hydrogen and lignin were determined as 0.4 and 0 respectively. Hydrogen was shown to be necessary under our reaction conditions as when helium was used as the gas atmosphere poor conversion was obtained. A clear solvent effect was observed with 100% methanol being more effective than 100% water or any combination of the two with a yield of alkylphenols >40% with a selectivity of >40% to substituted 4-propyl-2,6-dimethoxyphenol compounds. This high yield using methanol as a solvent was thought to be due to the ability of the methanol to inhibit re-polymerisation. IPA/water was also found to be an effective solvent combination with a yield of alkylphenols of >20%. The depolymerisation reaction was also studied over Rh/alumina and Ir/alumina catalysts. The rhodium catalyst was found to be the most active on a weight basis being slightly more active than platinum, however on a molar basis the platinum was much more active

    Comparing flow cytometry with culture-based methods for microbial monitoring and as a diagnostic tool for assessing drinking water treatment processes

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    Flow cytometry (FCM) and the ability to measure both total and intact cell populations through DNA staining methodologies has rapidly gained attention and consideration across the water sector in the past decade. In this study, water quality monitoring was undertaken over three years across 213 drinking water treatment works (WTW) in the Scottish Water region (Total n = 39,340). Samples subject to routine regulatory microbial analysis using culture-based methods were also analysed using FCM. In addition to final treated water, the bacterial content in raw water was measured over a one-year period. Three WTW were studied in further detail using on-site inter-stage sampling and analysis with FCM. It was demonstrated that there was no clear link between FCM data and the coliform samples taken for regulatory monitoring. The disinfectant Ct value (Ct = mg·min/L) was the driving factor in determining final water cell viability and the proportion of intact cells (intact/total cells) and the frequency of coliform detections in the water leaving the WTW. However, the free chlorine residual, without consideration of treatment time, was shown to have little impact on coliform detections or cell counts. Amongst the three treatment trains monitored in detail, the membrane filtration WTW showed the greatest log removal and robustness in terms of final water intact cell counts. Flow cytometry was shown to provide insights into the bacteriological quality of water that adds significant value over and above that provided by traditional bacterial monitoring

    HIRAYA

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    Hiraya is a sole proprietorship business founded in February 2020 by Jan Marc Portal, an ABM student in DLSU-SHS. Its mission is to provide the community with pouch bags that feature sustainability, affordability, and durability, promoting the Philippines’ indigenous designs using locally sourced materials such as Abaca and cotton canvas. Hiraya’s vision is to create a convenient and practical experience for the general lifestyle of the people by catering local products. The owner formed a business venture with his co-students in the ABM Strand, namely: Aeriel Punzalan (operations), Jarvis Servino (financial), Katriona Ureta (marketing), Jin Ha Kim (human resource), and Jiro Mhaye Salayo (advertising). The officers possess individual skills related to their departments, such as leadership, project management, and marketing, contributing to the development of Hiraya. The business took the opportunity to sell products through the online platform, reaching millennials and Gen-Z as its target market. The business’s location was strategically placed in Laguna. The venture considers itself to be different from its competitors as it features an accented Abaca design inspired by local Kalinga tattoo artists in its products. In terms of the initial capital, the business had invested Php 31,500 to operate. The capital was able to produce 120 bags, costing Php 349 each (39.6% mark-up). Once the break-even is reached, Hiraya intends to diversify its products by putting another Php 27,488 for capital. Hiraya plans to continually expand in the future to remain true to its cause in helping indigenous people as part of its social responsibility

    Protecting children from secondhand smoke: a mixed-methods feasibility study of a novel smoke-free home intervention

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    Background: Globally, 40 % of children under 14 years are regularly exposed to secondhand smoke (SHS), typically in their homes. There is limited evidence of the effectiveness of interventions to reduce children’s SHS exposure,and so the aim of this study was to test the feasibility and acceptability of a novel intervention to help parents and carers (caregivers) to reduce their children’s exposure to SHS at home. Methods: A novel multi-component intervention to support caregivers to reduce their children’s SHS exposure athome was tested in a two-phase feasibility study. The 12-week intensive intervention delivered in the homeconsisted of three components: behavioural support, nicotine replacement therapy (NRT) for temporary abstinenceand feedback on levels of SHS exposure in the form of children’s salivary cotinine (phase 1) or home air quality (PM2.5) (phase 2). Participants were caregivers who smoked inside their homes and had at least one child under the age of 5 years living with them the majority of the time. Mixed-methods were used to explore the acceptability and feasibility of the intervention as well as processes, particularly around recruitment and retention, for an exploratory efficacy trial. Results: Twelve caregivers completed the study, all received personalised feedback on SHS exposure and behavioural support to help them to make their homes smoke-free and the majority at least tried NRT. Saliva cotinine results were variable in phase 1, and therefore, measures of PM2.5 were used for feedback in phase 2.Behavioural support was well received with personalised feedback reported as being the key motivator for initiating and maintaining behaviour change. Conclusions: Recruiting disadvantaged caregivers was labour intensive, but once recruited, this novel intervention was both feasible and acceptable in supporting caregivers to reduce their children’s exposure to SHS at home. It is appropriate to test the efficacy of this novel intervention in an exploratory randomised controlled trial

    Optical tweezers for the study of microbubble dynamics in ultrasound

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    2005/2006Optical tweezers enable for non-destructive, contact-free manipulation of ultrasound contrast agent (UCA) microbubbles, which are used in medical imaging for enhancing the echogenicity of the blood pool and to quantify organ perfusion. Understanding the dynamics of ultrasound-driven contrast agent microbubbles from a fundamental physical standpoint is a first step for exploiting their acoustical properties and to develop new diagnostic and therapeutic applications. However, experiments on bubble dynamics presently suffer from a lack of control on bubble position, because of buoyancy, microstreaming and bubble clustering. In this respect, optical tweezers can be used to study UCA microbubbles under controlled and repeatable conditions, by positioning them away from interfaces and from neighboring bubbles. In addition, an ultra-high speed imaging system is required to record the dynamics of UCA microbubbles in ultrasound, as their oscillations occur on the nanoseconds timescale. In this thesis, optical tweezers and an ultra-high speed camera are integrated into an experimental setup to control the boundary conditions and record the oscillations of the microbubbles. Optical tweezers are commonly obtained by focusing a laser beam through a microscope objective, as the high intensity gradient in the focal region causes dielectric microparticles to be attracted in the focus. In the special case of microbubbles, which exhibit a lower refractive index than the surrounding liquid, the opposite situation arises: they are pushed away from the region of maximum intensity. Nevertheless, microbubbles can be trapped in the dark core of a donut-shaped trap, which can be obtained e.g. by focusing a Laguerre-Gaussian beam. In our setup, a Gaussian beam is converted to a Laguerre-Gaussian mode by using diffractive optical elements implemented on a spatial light modulator. This allows to trap and manipulate single or multiple microbubbles, and to control the distance from interfaces as well as the bubbleto- bubble distance. The “Brandaris 128” ultra-high speed camera is used, in combination with the optical tweezers, to recorded the bubble oscillations at a frame rate of 15 million frames per second. The influence of a rigid wall on the resonance frequency and oscillation amplitude was experimentally investigated. An experimental phospholipid-coated agent (BR-14, Bracco Research S.A., Geneva, Switzerland) was used throughout the experiments. A resonance frequency curve was recorded for the same bubble positioned at the wall and at controlled distance from the wall. The experiments show a drop in the resonance frequency for the bubble close to the ii Abstract wall, as expected from the theoretical models. These results are highly relevant for molecular imaging applications, where the response of targeted microbubbles needs to be discriminated from that of freely flowing ones. We also quantify the bubble-to-bubble interaction, in two ways: first, we compare the change of the radial oscillations of one bubble with and without a neighboring bubble. Second, we resolve the change in distance between two bubbles during ultrasonic insonation. This results from an acoustical, generally attractive, interaction force between the bubbles, termed secondary Bjerknes force. To understand this rich two-bubble dynamics, we couple a recent single-bubble model, accounting for both gas and monolayer properties with a model quantifying the mutual interaction of bubbles in their translation and oscillations. Experiments where optical tweezers are used as a force sensor to measure the binding force in an antigen-antibody complex at the single molecule level are also presented. In the future, the possibility of combining optical micromanipulation with the force-sensing capabilities of optical tweezers will open the way to a new class of experiments which will give us a deeper insight into fundamental bubble phenomena and find direct application to new ultrasound-assisted targeting strategies.XIX Ciclo197

    Accelerated discovery of thermoelectric materials::combinatorial facility and high-throughput measurement of thermoelectric power factor

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    A series of processes have been developed to facilitate the rapid discovery of new promising thermoelectric alloys. A novel combinatorial facility where elements are wire-fed and laser-melted was designed and constructed. Different sample compositions can be achieved by feeding different element wires at specific rates. The composition of all the samples prepared was tested by energy dispersive X-ray spectroscopy (EDS). Then, their thermoelectric properties (power factor) at room temperature were screened in a specially designed new high-throughput setup. After the screening, the thermoelectric properties can be mapped with the possibility of identifying compositional trends. As a proof-of-concept, a promising thermoelectric ternary system, Al–Fe–Ti, has been identified, demonstrating the capability of this accelerated approach
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