Approximate pole-placement controller using inverse plant dynamics for floor vibration control

PublishedThis is the final version of the article. Available from SPIE via the DOI in this record.Past research and field trials have demonstrated the viability of active vibration control (AVC) technologies for the mitigation of human induced vibrations in problematic floors. They make use of smaller units than their passive counterparts, provide quicker and more efficient control, can tackle multiple modes of vibration simultaneously and adaptability can be introduced to enhance their robustness. Predominantly single-input-single-output (SISO) and multi-SISO collocated sensor and actuator pairs have been utilized in direct output feedback schemes, for example, with direct velocity feedback (DVF). On-going studies have extended such past works to include model-based control approaches, for example, pole-placement (PP), which demonstrate increased flexibility of achieving desired vibration mitigation performances but for which stability issues must be adequately addressed. The work presented here is an extension to the pole-placement controller design using an algebraic approach that has been investigated in past studies. An approximate pole-placement controller formulated via the inversion of the floor dynamics, considered as minimum phase, is designed to achieve target closed-loop performances. Analytical studies and experimental tests are based on a laboratory structure and comparisons in vibration mitigation performances are made with a typical DVF control scheme with inner loop actuator compensation. It is shown that with minimal compensation, primarily in the form of notch filters and gain adjustment, the approximate pole-placement controller scheme is easily formulated and implemented and offers good vibration mitigation performance as well as the potential for isolation and control of specific target modes of vibration. Predicted attenuations of 22dB and 12dB in both the first and second vibration modes of the laboratory structure were also realized in the experimental studies for DVF and the approximate PP controller. © 2013 SPIE

Effect of Six Weeks of Oral \u3ci\u3eEchinacea purpurea\u3c/i\u3e Supplementation On Nitric Oxide Production

Echinacea purpurea, a purple coneflower plant of the compositae family (Asteraceae), is native to North America and commonly used as an herbal supplement to enhance immune function. Echinacea purpurea has been shown to stimulate macrophage activity which is a known stimulator of nitric oxide (NO) production. Echinacea purpurea supplementation (8,000 mg·d-1) in untrained (42.5 ± 1.6 mL·kg-1·min-1) males was shown to elicit a 63% increase (p \u3c 0.05) in serum erythropoietin (EPO) following two weeks of supplementation. This is supported in part by earlier findings which indicated that four weeks of Echinacea purpurea supplementation demonstrated a non-significant increase in maximal oxygen uptake (VO2max). It is plausible that Echinacea-induced EPO production may stimulate physiological responses independent of and/or in addition to erythropoiesis. There is also evidence suggesting EPO has vasculo-protective effects including the activation of endothelial nitric oxide synthase (eNOS). Based on these findings, a proposed non-hematological response to the Echinacea-induced increase in EPO could be enhanced NO production. The purpose of this investigation was to determine whether six weeks of oral Echinacea purpurea supplementation augmented NO production as a result of an Echinacea-induced increase in EPO and/or Echinacea-induced macrophage activity

An imbalance in progenitor cell populations reflects tumour progression in breast cancer primary culture models

Many factors influence breast cancer progression, including the ability of progenitor cells to sustain or increase net tumour cell numbers. Our aim was to define whether alterations in putative progenitor populations could predict clinicopathological factors of prognostic importance for cancer progression.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Developing a systematic method for extraction of microplastics in soils

Microplastics are an environmental issue of global concern. Although they have been found in a range of environments worldwide, their contamination in the terrestrial environment is poorly understood. The lack of standardised methods for their detection and quantification is a major obstacle for determining the risk they pose to soil environments. Here we present a systematic comparison of microplastic extraction methods from soils, taking into account the characteristics of the soil medium to determine the best methods for quantification. The efficiency of organic matter removal using hydrogen peroxide, potassium hydroxide and Fenton's reagent was measured. Soils with a range of particle size distribution and organic matter content were spiked with a variety of microplastic types. Density separation methods using sodium chloride, zinc chloride and canola oil were tested. Recovery efficiencies were calculated and the impact of the reagents on the microplastics was quantified using Attenuated Total Reflectance (ATR) Fourier Transform-Infrared (FTIR) spectroscopy. The optimal organic removal method was found to be hydrogen peroxide. The recovery efficiency of microplastics was variable across polymer types. Overall, canola oil was shown to be the optimal method for density separation, however, efficiency was dependent on the amount of organic matter in the soil. This outcome highlights the importance of including matrix-specific calibration in future studies considering a wide range of microplastic types, to avoid underestimation of microplastic contamination. We show here that methods for extracting microplastics from soils can be simple, cost-effective and widely applicable, which will enable the advancement of microplastic research in terrestrial environments

Developing a systematic method for extraction of microplastics in soils

Microplastics are an environmental issue of global concern. Although they have been found in a range of environments worldwide, their contamination in the terrestrial environment is poorly understood. The lack of standardised methods for their detection and quantification is a major obstacle for determining the risk they pose to soil environments. Here we present a systematic comparison of microplastic extraction methods from soils, taking into account the characteristics of the soil medium to determine the best methods for quantification. The efficiency of organic matter removal using hydrogen peroxide, potassium hydroxide and Fenton's reagent was measured. Soils with a range of particle size distribution and organic matter content were spiked with a variety of microplastic types. Density separation methods using sodium chloride, zinc chloride and canola oil were tested. Recovery efficiencies were calculated and the impact of the reagents on the microplastics was quantified using Attenuated Total Reflectance (ATR) Fourier Transform-Infrared (FTIR) spectroscopy. The optimal organic removal method was found to be hydrogen peroxide. The recovery efficiency of microplastics was variable across polymer types. Overall, canola oil was shown to be the optimal method for density separation, however, efficiency was dependent on the amount of organic matter in the soil. This outcome highlights the importance of including matrix-specific calibration in future studies considering a wide range of microplastic types, to avoid underestimation of microplastic contamination. We show here that methods for extracting microplastics from soils can be simple, cost-effective and widely applicable, which will enable the advancement of microplastic research in terrestrial environments

Cosmic flows in the nearby universe from Type Ia Supernovae

Peculiar velocities are one of the only probes of very large-scale mass density fluctuations in the nearby Universe. We present new "minimal variance" bulk flow measurements based upon the "First Amendment" compilation of 245 Type Ia supernovae (SNe) peculiar velocities and find a bulk flow of 249 +/- 76 km/s in the direction l= 319 +/- 18 deg, b = 7 +/- 14 deg. The SNe bulk flow is consistent with the expectations of \Lambda CDM. However, it is also marginally consistent with the bulk flow of a larger compilation of non-SNe peculiar velocities (Watkins, Feldman, & Hudson 2009). By comparing the SNe peculiar velocities to predictions of the IRAS Point Source Catalog Redshift survey (PSCz) galaxy density field, we find \Omega_{m}^{0.55} \sigma_{8,lin} = 0.40 +/- 0.07, which is in agreement with \Lambda CDM. However, we also show that the PSCz density field fails to account for 150 +/- 43 km/s of the SNe bulk motion.Comment: MNRAS in press, 9 pages, 4 figures, 4 table

A continental-scale validation of ecosystem service models

Faced with environmental degradation, governments worldwide are developing policies to safeguard ecosystem services (ES). Many ES models exist to support these policies, but they are generally poorly validated, especially at large scales, which undermines their credibility. To address this gap, we describe a study of multiple models of five ES, which we validate at an unprecedented scale against 1675 data points across sub-Saharan Africa. We find that potential ES (biophysical supply of carbon and water) are reasonably well predicted by the existing models. These potential ES models can also be used as inputs to new models for realised ES (use of charcoal, firewood, grazing resources and water), by adding information on human population density. We find that increasing model complexity can improve estimates of both potential and realised ES, suggesting that developing more detailed models of ES will be beneficial. Furthermore, in 85% of cases, human population density alone was as good or a better predictor of realised ES than ES models, suggesting that it is demand, rather than supply that is predominantly determining current patterns of ES use. Our study demonstrates the feasibility of ES model validation, even in data-deficient locations such as sub-Saharan Africa. Our work also shows the clear need for more work on the demand side of ES models, and the importance of model validation in providing a stronger base to support policies which seek to achieve sustainable development in support of human well-being

Attitudinal and Demographic Predictors of Measles-Mumps-Rubella Vaccine (MMR) Uptake during the UK Catch-Up Campaign 2008–09: Cross-Sectional Survey

Background and Objective Continued suboptimal measles-mumps-rubella (MMR) vaccine uptake has re-established measles epidemic risk, prompting a UK catch-up campaign in 2008–09 for children who missed MMR doses at scheduled age. Predictors of vaccine uptake during catch-ups are poorly understood, however evidence from routine schedule uptake suggests demographics and attitudes may be central. This work explored this hypothesis using a robust evidence-based measure. Design Cross-sectional self-administered questionnaire with objective behavioural outcome. Setting and Participants 365 UK parents, whose children were aged 5–18 years and had received <2 MMR doses before the 2008–09 UK catch-up started. Main Outcome Measures Parents' attitudes and demographics, parent-reported receipt of invitation to receive catch-up MMR dose(s), and catch-up MMR uptake according to child's medical record (receipt of MMR doses during year 1 of the catch-up). Results Perceived social desirability/benefit of MMR uptake (OR = 1.76, 95% CI = 1.09–2.87) and younger child age (OR = 0.78, 95% CI = 0.68–0.89) were the only independent predictors of catch-up MMR uptake in the sample overall. Uptake predictors differed by whether the child had received 0 MMR doses or 1 MMR dose before the catch-up. Receipt of catch-up invitation predicted uptake only in the 0 dose group (OR = 3.45, 95% CI = 1.18–10.05), whilst perceived social desirability/benefit of MMR uptake predicted uptake only in the 1 dose group (OR = 9.61, 95% CI = 2.57–35.97). Attitudes and demographics explained only 28% of MMR uptake in the 0 dose group compared with 61% in the 1 dose group. Conclusions Catch-up MMR invitations may effectively move children from 0 to 1 MMR doses (unimmunised to partially immunised), whilst attitudinal interventions highlighting social benefits of MMR may effectively move children from 1 to 2 MMR doses (partially to fully immunised). Older children may be best targeted through school-based programmes. A formal evaluation element should be incorporated into future catch-up campaigns to inform their continuing improvement

Simulation study of the link between molecular association and reentrant miscibility for a mixture of molecules with directional interactions

The reentrant liquid-liquid miscibility of a symmetrical mixture with highly directional bonding interactions is studied by Gibbs ensemble Monte Carlo simulation. The resulting closed loop of immiscibility and the corresponding lower critical solution temperature are shown to be a direct consequence of the dramatic increase in association between unlike components as the temperature is lowered. Our exact calculations for an off-lattice system with a well-defined anisotropic potential confirm the findings of previous theoretical studies.Dirección General de Investigación Científica y Técnica PB94-144