On the Development of the Self Starting Double Multivariate Exponentially Weighted Moving Average And Covariance Control Chart

Control charts are an important element for monitoring production processes in a wide array of industries. A strong performing control chart is one that responds quickly to undesirable changes in a production process. This work demonstrates the expansion of Multivariate Exponentially Weighted Moving Average and Covariance (MEWMAC) control chart to be doubly weighted in efforts to improve performance by reducing out of control run lengths (ARL1) when changes occur in either the process mean vector or covariance matrix. Metric derivation and justification are provided. Simulations under different scenarios provide comparison of the new control chart mechanism to those already established in the literature. Conclusions and recommendations for future research are discussed

Optical Modelling of a Fresnel Mirror Field for the Development of a Spectral Splitting CPVT Collector

Concentrating photovoltaic thermal (CPVT) collectors could contribute to supply renewable mid-temperature heat and electricity simultaneously, e.g. for applications in the industrial sector. Although CPVT can be still seen as a niche technology, it has a high potential for the future. One of the technological challenges of CPVT are the contradictory temperature requirements within the receiver, as the thermal part should provide temperatures as high as possible, while the electrical part consisting of conventional PV cells shows best efficiency at low temperature. Therefore, this research work focuses on the development of a CPVT collector with integrated Spectral Splitting, which is an approach to overcome the discrepancy of internal temperature demands. The basis for the developed CPVT collector is a Fresnel mirror field consisting of 28 mirror stripes and providing a gross area of 13.34 m². The presented paper describes the optical modelling of this Fresnel mirror field, which was necessary before working on the receiver design in order to yield the dimensions of expected focus image on the receiver input plane. Furthermore, the resulting concentrated irradiance is a major parameter for calculating thermal and electrical efficiencies of the system, thus, this was another target for the modelling work. The optical model for the Fresnel mirror field was developed in MATLAB™ in a general way, as the number of mirrors and all geometric parameters are set as input variables. This makes it possible to use it not only for the available mirror field, but also for the design and optimisation of any other Fresnel mirror system. The model calculates the single mirror angles depending on the sun position and considers all four mechanisms of internal shading that are typical for such concentrators. Furthermore, the cosine losses in transversal and longitudinal direction are calculated. The results of the modelling are satisfying, as the experimental validation on the present mirror field was successful. The model provides comprehensive outcomes like the geometric efficiency depending on the sun´s elevation angle, the mean geometric efficiency at varying geometric parameters, local and mean irradiance in the receiver input plane, as well as mean irradiance and total solar input depending on time

Funding AIDS programmes in the era of shared responsibility:an analysis of domestic spending in 12 low-income and middle-income countries

Background As the incomes of many AIDS-burdened countries grow and donors’ budgets for helping to fi ght the disease tighten, national governments and external funding partners increasingly face the following question: what is the capacity of countries that are highly aff ected by AIDS to fi nance their responses from domestic sources, and how might this aff ect the level of donor support? In this study, we attempt to answer this question. Methods We propose metrics to estimate domestic AIDS fi nancing, using methods related to national prioritisation of health spending, disease burden, and economic growth. We apply these metrics to 12 countries in sub-Saharan Africa with a high prevalence of HIV/AIDS, generating scenarios of possible future domestic expenditure. We compare the results with total AIDS fi nancing requirements to calculate the size of the resulting funding gaps and implications for donors. Findings Nearly all 12 countries studied fall short of the proposed expenditure benchmarks. If they met these benchmarks fully, domestic spending on AIDS would increase by 2·5 times, from US$2·1 billion to$5·1 billion annually, covering 64% of estimated future funding requirements and leaving a gap of around a third of the total $7·9 billion needed. Although upper-middle-income countries, such as Botswana, Namibia, and South Africa, would become fi nancially self-reliant, lower-income countries, such as Mozambique and Ethiopia, would remain heavily dependent on donor funds. Interpretation The proposed metrics could be useful to stimulate further analysis and discussion around domestic spending on AIDS and corresponding donor contributions, and to structure fi nancial agreements between recipient country governments and donors. Coupled with improved resource tracking, such metrics could enhance transparency and accountability for effi cient use of money and maximise the eff ect of available funding to prevent HIV infections and save lives

Book reviews

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43643/1/11186_2004_Article_BF00160779.pd

BOOST -- A Satellite Mission to Test Lorentz Invariance Using High-Performance Optical Frequency References

BOOST (BOOst Symmetry Test) is a proposed satellite mission to search for violations of Lorentz invariance by comparing two optical frequency references. One is based on a long-term stable optical resonator and the other on a hyperfine transition in molecular iodine. This mission will allow to determine several parameters of the standard model extension in the electron sector up to two orders of magnitude better than with the current best experiments. Here, we will give an overview of the mission, the science case and the payload.Comment: 11 pages, 2 figures, accepted for publication in Phys. Rev.