A Linear Control Theory Analysis of Transverse Coherent Bunch Instabilities Feedback Systems (The Control Theory Approach to Hill's Equation)

There is an on-going effort to build a feedback system for transverse coherent bunch instabilities for ALS [1,2,3]. The beam dynamics issues were already addressed in the conceptual design report [ 4] and more detailed studies have been earned out [5]. On-going work is the development of a general simulation code including the full 6-dirnensional dynamics for coherent bunch instabilities (by using Taylor series maps) as well as related feedback systems [6]. Recently, there has been some confusion about how to choose the gain matrix in the feedback loop. In particular, the current analytical formulas were found (from numerical simulations by D. Briggs using the newly developed simulation code) to only be valid if ak = 0 at the kicker. This motivated us to perform a more careful design study of the transverse feedback system based on linear control theory. This paper presents the general formulas for tuning the system. Also, by a careful analytical study of the performance of the system, based on linear accelerator theory combined with linear control theory for sampled systems, we discovered that the performance of the system can be dramatically improved by slightly changing one of the two coefficients in the gain matrix

Innovations in Monitoring Vital Events:Mobile Phone SMS Support to Improve Coverage of Birth and Death Registration: A Scalable Solution

Civil Registration (CR) of births and deaths is an essential component of any health information system.\ud Globally, across low income countries, CR suffers from unacceptably poor quality coverage. This Health\ud Information Systems Knowledge Hub (HIS Hub) working paper summarises and reports the results, conclusions and outlook from a small six-month project that investigated the potential of introducing a mobile phone step into the routine CR system in a rural district in Tanzania. The project developed a computer application that could receive SMS messages—from existing basic mobile phones of community-based CR officers—and feed them directly to the District Registrar’s office and computer. The message contained the details from the birth or death notification form. The system provided instant access to notifications and automatic feedback to the Village Executive Officer (VEO) if the family that experienced the birth or death event failed to register the event for certification. It also prompted the VEO to follow up with the family by conducting a questionnaire, administered by mobile phone, to determine and communicate the reasons for the non-registration. The District Civil Registrar was also able to monitor trends in these notifications via a user-friendly webbased browser and dashboard. The system was tested for six months and validated against an independent prospective household surveillance system that monitors pregnancies, births and deaths in the same period. In summary, the findings showed that the routine CR system notified only 28% of total births in the period. Adding the SMS step increased this to 51% of births. The routine CR system notified only 2.1% of deaths in the period. Adding the SMS step increased this to 14% of deaths. The SMS step therefore made significant improvements in the notification step (and modest improvements in the registration step) of routine CR. However, both notifications and registrations still fell well short of reality at community level. The most important finding of this pilot is that the current CR system in at least the study district, and likely in most of rural Tanzania, is essentially unable to provide adequate registration coverage for births and deaths, and that coverage is so low that even log order improvements are insufficient to lift it to satisfactory levels (in excess of 90%). This, as yet, says nothing regarding the quality of the data. No overwhelming reason is provided by families for the low reporting rate, suggesting that the problems are highly systemic and will need a radical redesign of CR processes to solve. To the extent that similar problems prevail in other low-income countries, it is clear that whatever these processes will be, some form of scalable real-time mobile communication such as SMS will greatly facilitate coverage levels. This pilot shows\ud that such technology is feasible. But these results also emphasise the need for an end-to-end overhaul of the\ud architecture and processes of how CR systems are built and integrated into the information fabric of a country. Small incremental technical fixes will not suffice\u

Comparisons of Current Practices of Computer Use and Training by Industry Type of Small Businesses in the Portland Area

The problem was to determine what are the current computer uses, and training practices for small businesses in the Portland area. Comparisons were made by industry type

Specific Impulse and Mass Flow Rate Error

Specific impulse is defined in words in many ways. Very early in any text on rocket propulsion a phrase similar to .specific impulse is the thrust force per unit propellant weight flow per second. will be found.(2) It is only after seeing the mathematics written down does the definition mean something physically to scientists and engineers responsible for either measuring it or using someone.s value for it

Language switching in a digital library; does it make a difference if the default language is set to Maori?

In this paper we investigate the effect of default interface language on usage patterns of the Niupepa digital library (a collection of historic Māori language newspapers), by switching the default interface language between Māori and English in alternate weeks. Transaction analysis of the Niupepa collection logs indicates that changing default language affects the length of user sessions and the number of actions within sessions, and that the English language interface was used most frequently

Optical Detection of Formaldehyde

The potential for buildup .of formaldehyde in closed space environments poses a direct health hazard to personnel. The National Aeronautic Space Agency (NASA) has established a maximum permitted concentration of 0.04 ppm for 7 to 180 days for all space craft. Early detection is critical to ensure that formaldehyde levels do not accumulate. above these limits. New sensor technologies are needed to enable real time,in situ detection in a compact and reusable form factor. Addressing this need,research into the use of reactive fluorescent dyes which reversibly bind to formaldehyde (liquid or gas) has been conducted to support the development of a formaldehyde.sensor. In the presence of formaldehyde the dyes' characteristic fluorescence peaks shift providing the basis for an optical detection. Dye responses to formaldehyde exposure were characterized; demonstrating the optical detection of formaldehyde in under 10 seconds and down to concentrations of 0.5 ppm. To .incorporate the dye .in.an optical sensor device requires. a means of containing and manipulating the dye. Multiple form factors using two dissimilar s~bstrates were considered to determine a suitable configuration. A prototype sensor was demonstrated and considerations for a field able sensor were presented. This research provides a necessary first step toward the development of a compact, reusable; real time optical formaldehyde sensor suitable for use in the U.S. space program

Hydraulic Analysis of Surcharged Storm Sewer Systems

Surcharge in a storm sewer system is the condition in which an entire sewer section is submerged and the pipe is flowing full under pressure. Flow in a surcharged storm sewer is essentially slowly varying unsteady pipe flow and methods for analyzing this type of flow are investigated. In this report the governing equations for unsteady fluid flow in pressurized storm sewers are presented. From these governing equations three numerical models are developed using various assumptions and simplifications. These flow models are applied to several example storm sewer systems under surcharge conditions. Plots of hydraulic grade and flow throughout the sewer network are presented in order to evaluate the ability of each model to accurately analyze surcharged storm sewer systems. Computer programs are developed for each of the models considered and these programs are presented and documented in the Appendix of this report