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The evaporation of multiple sessile droplets is both scientifically interesting and practically important, occurring in many natural and industrial applications. Although there are simple analytic expressions to predict evaporation rates of single droplets, there are no such frameworks for general configurations of droplets of arbitrary size, contact angle or spacing. However, a recent theoretical contribution by Masoud, Howell & Stone (J. Fluid Mech., vol. 927, 2021, R4) shows how considerable insight can be gained into the evaporation of arbitrary configurations of droplets without having either to obtain the solution for the concentration of vapour in the atmosphere or to perform direct numerical simulations of the full problem. The theoretical predictions show excellent agreement with simulations for all configurations, only deviating by 25 % for the most confined droplets.

We consider the problem of adaptive observer design for systems in which the uncertainties are modelled by ill-conditioned regressors or/and unknown parameters of the model enter the equations nonlinearly. It is shown that both of these critical issues can be overcome in a unified yet simple way, provided that the usual requirement of global asymptotic stability of solutions of model-observer system is replaced with a weaker constraint of mere set-attractivity. The claim is illustrated with a particular adaptive observer design problem.

Induction of humoral responses to HIV at mucosal compartments without inflammation is important for vaccine design. We developed charged wax nanoparticles that efficiently adsorb protein antigens and are internalized by DC in the absence of inflammation. HIV-gp140-adsorbed nanoparticles induced stronger in vitro T-cell proliferation responses than antigen alone. Such responses were greatly enhanced when antigen was co-adsorbed with TLR ligands. Immunogenicity studies in mice showed that intradermal vaccination with HIV-gp140 antigen-adsorbed nanoparticles induced high levels of specific IgG. Importantly, intranasal immunization with HIV-gp140-adsorbed nanoparticles greatly enhanced serum and vaginal IgG and IgA responses. Our results show that HIV-gp140-carrying wax nanoparticles can induce strong cellular/humoral immune responses without inflammation and may be of potential use as effective mucosal adjuvants for HIV vaccine candidates.

We consider the problem of how to recover the state and parameter values of typical model neurons, such as Hindmarsh-Rose, FitzHugh-Nagumo, Morris-Lecar, from in-vitro measurements of membrane potentials. In control theory, in terms of observer design, model neurons qualify as locally observable. However, unlike most models traditionally addressed in control theory, no parameter-independent diffeomorphism exists, such that the original model equations can be transformed into adaptive canonic observer form. For a large class of model neurons, however, state and parameter reconstruction is possible nevertheless. We propose a method which, subject to mild conditions on the richness of the measured signal, allows model parameters and state variables to be reconstructed up to an equivalence class. © 2010 World Scientific Publishing Company.

We consider the problem of state and parameter estimation for a class of nonlinear oscillators defined as a system of coupled nonlinear ordinary differential equations. Observable variables are limited to a few components of state vector and an input signal. This class of systems describes a set of canonic models governing the dynamics of evoked potential in neural membranes, including Hodgkin-Huxley, Hindmarsh-Rose, FitzHugh-Nagumo, and Morris-Lecar models. We consider the problem of state and parameter reconstruction for these models within the classical framework of observer design. This framework offers computationally-efficient solutions to the problem of state and parameter reconstruction of a system of nonlinear differential equations, provided that these equations are in the so-called adaptive observer canonic form. We show that despite typical neural oscillators being locally observable they are not in the adaptive canonic observer form. Furthermore, we show that no parameter-independent diffeomorphism exists such that the original equations of these models can be transformed into the adaptive canonic observer form. We demonstrate, however, that for the class of Hindmarsh-Rose and FitzHugh-Nagumo models, parameter-dependent coordinate transformations can be used to render these systems into the adaptive observer canonical form. This allows reconstruction, at least partially and up to a (bi)linear transformation, of unknown state and parameter values with exponential rate of convergence. In order to avoid the problem of only partial reconstruction and at the same time to be able to deal with more general nonlinear models in which the unknown parameters enter the system nonlinearly, we present a new method for state and parameter reconstruction for these systems. The method combines advantages of standard Lyapunov-based design with more flexible design and analysis techniques based on the notions of positive invariance and small-gain theorems. We show that this flexibility allows to overcome ill-conditioning and non-uniqueness issues arising in this problem. Effectiveness of our method is illustrated with simple numerical examples.

Employee engagement in the UK remains stubbornly low. However, by identifying and proactively managing the key drivers of employee engagement, and creating a balanced and meaningful rewards framework, McDonald's in the UK have significantly enhanced the commitment and performance of their workforce.

Purpose – The purpose of this paper is to present a model for sustainable workplace flexibility developed and successfully implemented by McDonald's in the UK and first presented at the CIPD Annual Conference in October 2006Design/methodology/approach – The paper describes the four key organizational requirements if balanced, sustainable workplace flexibility is to be created which benefit both employees and employers alike. These requirements are illustrated with examples of how they have been implemented within McDonald's and presented in the context of McDonald's business model.Findings – Where possible an objective, third‐party assessment of the impact of McDonald's approach has been provided.Practical implications – Successful delivery of the four key organizational requirements will enable an organization to achieve sustainable workplace flexibility.Originality/value – This paper presents a proven, practical approach to delivering sustainable workplace flexibility. It will be of particular value to ...

Solvent relaxation NMR has been used to estimate the surface areas and wettability of various types of nanostructured carbon materials in a range of solvents including water, ethanol, and tetrahydrofuran. We illustrate the application of the technique through several short case studies using samples including nanocarbon blacks, graphene oxide, nanographites, and porous graphenes. The technique is shown to give a good measure of surface area, correlating well with conventional surface area estimates obtained by nitrogen adsorption, transmission electron microscopy, or light scattering for the non-porous samples. NMR relaxation has advantages in terms of speed of analysis and being able to use concentrated, wet, and opaque samples. For samples that are porous, two distinct surface areas can be estimated assuming the two environments ('inner' and 'outer') have the same surface chemistry, and that there is a slow exchange of solvent molecules between them. Furthermore, we show that differences in wettability and dispersability between samples dispersed in water, ethanol, and cyclopentanone can be observed, along with changes to the surface chemistry of the interface. Copyright © 2015 John WileySons, Ltd.

Background. Microfine zinc oxide and microfine titanium dioxide are particulate sunscreen ingredients that absorb broad-spectrum ultraviolet (UV) irradiation. Objective. We compare microfine zinc oxide and microfine titanium dioxide for their abilities to attenuate UVA radiation and their relative whiteness in cosmetic formulations. Methods. UVA attenuation was measured by diffuse reflectance spectroscopy on normal human skin in vivo. Whiteness was determined by reflectance density of dried coatings on a black background of the two particulates at varying concentrations. Results. Microfine zinc oxide demonstrates superior protection compared to microfine titanium dioxide in the UV spectrum between 340 and 380 nm. Microfine zinc oxide is less white than titanium dioxide at all concentrations. Conclusion. Microfine zinc oxide is superior to microfine titanium dioxide as a sunscreen ingredient. It is more protective against long-wave UVA and is less white at a given concentration.

• The article explores the current practice of outsourcing aspects of HR activity. • The extent, rationale for and nature of outsourcing within the HR function in 60 UK manufacturing companies are examined. • The implications of inadequate costings, lack of measurement of service levels and underestimation of the people and cultural aspects are discussed. • The significance of outsourcing for the practitioner role and concomitant skills is considered. • A five-stage framework to guide practitioner action is proposed. © 1997 John Wiley & Sons, Ltd.

Skin is constantly assaulted by sun exposure and terrestrial solar ultraviolet radiation (UVR) is a major factor deleterious to our health. The most reliable approach to sun protection is to cover up the skin by using a thin film of a topical sunscreen formulation containing active chemical ingredients that absorb, scatter or reflect the incident UVR to reduce the direct penetration and effect of UV exposure. Physical (particulate) actives are very stable and benign. From a regulatory perspective, zinc oxide and titanium dioxide are the only ones universally allowed as sunscreen actives. The development of sunscreen formulations containing ZnO and TiO2 requires knowledge of their optical properties as these dictate both the resulting aesthetics and the efficacy of the final sunscreen product and, thereby, acceptance by the user; these factors critically impact the economics of commercial sunscreen manufacturing and sales. The optical properties are uniquely related to the particle size (distribution) and particle morphology (e.g., surface area) of the two oxides. Precise measurement of these parameters is therefore a critical metric in formulating sunscreen products. X-ray disc centrifugation, acoustic attenuation spectroscopy and nuclear magnetic resonance relaxation are useful techniques that can be used to characterize fundamental properties of particulate suspensions at concentrations that are commercially relevant.

Background: Microfine zinc oxide (Z-Cote) is used as a transparent broad-spectrum sunblock to attenuate UV radiation (UVR), including UVA I (340-400 nm). Objective: Our purpose was to assess the suitability of microfine zinc oxide as a broad-spectrum photoprotective agent by examining those properties generally considered important in sunscreens: attenuation spectrum, sun protection factor (SPF) contribution, photostability, and photoreactivity. Methods: Attenuation spectrum was assessed by means of standard spectrophotometric methods. SPF contribution was evaluated according to Food and Drug Administration standards. Photostability was measured in vitro by assessing SPF before and after various doses of UVR. Photoreactivity was evaluated by subjecting a microfine zinc oxide/organic sunscreen formulation to escalating doses of UVR and determining the percentage of organic sunscreen remaining. Results: Microfine zinc oxide attenuates throughout the UVR spectrum, including UVA I. It is photostable and does not react with organic sunscreens under irradiation. Conclusion: Microfine zinc oxide is an effective and safe sunblock that provides broad-spectrum UV protection, including protection from long-wavelength UVA. (J Am Acad Dermatol 1999;40:85-90.)

The particle size and particle size distribution (PSD) of paints, inks etc. fundamentally affect coating performance. Small changes in the PSD can often dramatically alter product performance. Popular sizing methods based on laser light scattering and laser diffraction are fast, but have inherently low resolution. The Disc Centrifuge is a device which uses a rapidly spinning disc to determine the sedimentation time and, ultimately, the particle size of colloidal suspensions. This device requires no calibration since it relies on Stokes1 law for centrifugal sedimentation. Recent advances in disc centrifuge design and data analysis mean that these devices can now yield high resolution results in the size range 0.01 to tens of micrometres. The basics of the disc centrifuge are outlined and data are presented which illustrate the utility of the technique to latex and carbon black size analysis.