An improved switching converter model

The nonlinear modeling and analysis of dc-dc converters in the continuous mode and discontinuous mode was done by averaging and discrete sampling techniques. A model was developed by combining these two techniques. This model, the discrete average model, accurately predicts the envelope of the output voltage and is easy to implement in circuit and state variable forms. The proposed model is shown to be dependent on the type of duty cycle control. The proper selection of the power stage model, between average and discrete average, is largely a function of the error processor in the feedback loop. The accuracy of the measurement data taken by a conventional technique is affected by the conditions at which the data is collected

Optical bistability in Er-Yb co-doped phosphate glass microspheres at room temperature

We experimentally demonstrate optical bistability in Er3+-Yb3+ phosphate glass microspheres at 295 K. Bistability is associated with both Er3+ fluorescence and lasing behavior, and chromatic switching. The chromatic switching results from an intrinsic mechanism exploiting the thermal coupling of closely-spaced energy levels, and occurs simultaneously with the intensity switching. A contrast ratio of 3.2 has been obtained for chromatic switching, and the intensity switching shows ratios of 2.4 for 550 nm and, 1.8 for the 660 nm fluorescence emissions, and 11 for the IR lasing at 1.5 um. Concurrent with these observations, we investigate a temperature dependent absorption of pump power which exhibits bistable behavior. The influences of the host matrix on lasing and fluorescence mechanisms are highlighted.Comment: 22 pages, 6 figure

“Availability is the poor cousin of marketing and pricing”: Qualitative study of stakeholders’ views on policy priorities around tobacco and alcohol availability

BackgroundReducing alcohol and tobacco availability is one potential way to reduce harm from these unhealthy commodities. This study explores key stakeholders’ views in relation to policy priorities and considerations for both alcohol and tobacco availability.MethodsWe conducted semi-structured interviews with 14 stakeholders from alcohol and/or tobacco third sector organizations, government, public health and licensing in Scotland. Interviews explored their views on alcohol/tobacco availability, including its place in the policy landscape and experiences in gaining support for policies. Data were analyzed using thematic analysis.ResultsStakeholders believed that alcohol and tobacco availability have not received as much policy attention as pricing and marketing. Stakeholders highlighted the importance of public support and having sufficient evidence to inform policy. Key considerations for future policies include: drawing on lessons from tobacco control policies to address alcohol availability, considering different aspects of availability (especially online availability), ensuring policies reflect their local context, considering the impact of policies on children, and managing retailers’ involvement in the policy process.ConclusionThis study highlights key considerations for policies to address alcohol and tobacco availability. There is a need for more research to consider retailers’ views and provide greater detail on specific policy suggestions

“Availability is the poor cousin of marketing and pricing”: qualitative study of stakeholders’ views on policy priorities around tobacco and alcohol availability

Background: Reducing alcohol and tobacco availability is one potential way to reduce harm from these unhealthy commodities. This study explores key stakeholders’ views in relation to policy priorities and considerations for both alcohol and tobacco availability. Methods: We conducted semi-structured interviews with 14 stakeholders from alcohol and/or tobacco third sector organizations, government, public health and licensing in Scotland. Interviews explored their views on alcohol/tobacco availability, including its place in the policy landscape and experiences in gaining support for policies. Data were analyzed using thematic analysis. Results: Stakeholders believed that alcohol and tobacco availability have not received as much policy attention as pricing and marketing. Stakeholders highlighted the importance of public support and having sufficient evidence to inform policy. Key considerations for future policies include: drawing on lessons from tobacco control policies to address alcohol availability, considering different aspects of availability (especially online availability), ensuring policies reflect their local context, considering the impact of policies on children, and managing retailers’ involvement in the policy process. Conclusion: This study highlights key considerations for policies to address alcohol and tobacco availability. There is a need for more research to consider retailers’ views and provide greater detail on specific policy suggestions.</p

Influence of vibrations on indentation and compression strength of sea ice

Indentation and compression strengths of floating sea ice subjected to vibrations is discussed. The experiments were performed on the land fast ice of the Van-Mijen Fjord in March of 2018 and 2019. The ice thickness was around 70 cm, and the ice salinity was 4-5 ppt. Vibrations were introduced in the ice by the vibration plate with weight of 400 kg before the tests during 10-15 min. The vibration plate was standing and vibrating on the ice surface. The spectrum of vibrations was recorded with accelerometers. Analysis of thin sections of ice was performed on the place of the field works. Indentation tests were performed with the original hydraulic rig on natural ice and ice subjected to the action of vibrating plate. It was discovered that stroke rates tests were higher in the tests performed on the ice subjected to vibrations. Uniaxial compression tests were also performed on ice cores taken from the natural ice and from the ice subjected to the vibrations. Uniaxial compression strength of ice cores taken from the ice subjected to vibrations was higher than in the tests with natural ice

Shortcomings in public health authorities’ videos on COVID-19: limited reach and a creative gap

Science Communication and Societ

A Monte Carlo based phase space model for quality assurance of intensity modulated radiotherapy incorporating leaf specific characteristics

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134797/1/mp3409.pd

The neighbourhood social environment and alcohol use among urban and rural Scottish adolescents

Funding for the Scottish Health Behaviour in School-aged Children was provided by NHS Scotland. This work was also supported by the 600th Anniversary Ph.D. Scholarship which was awarded to Gina Martin by the University of St Andrews.Objectives This research examined the relationship between neighbourhood social environmental characteristics and drinking outcomes among a sample of urban and rural adolescents. Methods From a sample of 1558 Scottish secondary schoolchildren, surveyed as part of the 2010 Health Behaviour in School-aged Children study, we modelled three drinking outcomes on a variety of neighbourhood conditions, including social cohesion, disorder, alcohol outlet density, deprivation, and urban/rurality. Nested and cross-classified multilevel logistic regressions were specified. Results An urban-to-rural gradient was found with non-urban adolescents exhibiting higher odds of having ever drank. Neighbourhood social cohesion related to having ever drank. Among drinkers, those living in accessible small towns had higher odds of weekly drinking and drunkenness compared to urban areas. Higher odds of drunkenness were also found in remote rural areas. Those residing in the least deprived areas had lower odds of weekly drinking. Conclusions In Scotland, inequalities exist in adolescent alcohol use by urban/rurality and neighbourhood social conditions. Findings support regional targeting of public health efforts to address inequalities. Future work is needed to develop and evaluate intervention and prevention approaches for neighbourhoods at risk.Publisher PDFPeer reviewe

Geographical differences in the financial impacts of different forms of tobacco licence fees on small retailers in Scotland

Objective Retailer licencing fees are a promising avenue to regulate tobacco availability. However, they face strong opposition from retailers and the tobacco industry, who argue significant financial impacts. This study compares the impacts of different forms of tobacco licence schemes on retailers’ profits in Scotland. Methods We calculated gross profits from tobacco sales in 179 convenience stores across Scotland using 1 099 697 electronic point-of-sale records from 16 weeks between 2019 and 2022. We estimated different fees using universal, volumetric and separate urban/rural schemes. We identified the point at which 50% of retailers would no longer make a gross profit on tobacco sales for each scheme and modelled the financial impact of 10 incremental fee levels. The financial impact was assessed based on changes in retailers’ tobacco gross profits. Differences by neighbourhood deprivation and urban/rural status were examined. Results The gross profit from tobacco per convenience store averaged £15 859/year. Profits were 2.29 times higher in urban (vs rural) areas and 1.59 times higher in high-deprivation (vs low-deprivation) areas, attributable to higher sales volumes. Tobacco gross profit decreased proportionally with increasing fee levels. Universal and urban/rural fees had greater gross profit reductions in rural and/or less deprived areas, where profits were lower, compared with volumetric fees. Conclusion The introduction of tobacco licence fees offers a potential opportunity for reducing the availability of tobacco retailers. The likely impact of a tobacco licence fee is sensitive to the type of licence scheme implemented, the level at which fees are set and the retailers’ location in relation to neighbourhood deprivation and rurality