Mathematical notation in formal specification: too difficult forthe masses?

The phrase “not much mathematics required” can imply a variety of skill levels. When this phrase is applied to computer scientists, software engineers, and clients in the area of formal specification, the word “much” can be widely misinterpreted with disastrous consequences. A small experiment in reading specifications revealed that students already trained in discrete mathematics and the specification notation performed very poorly; much worse than could reasonably be expected if formal methods proponents are to be believed     

Surfactants as replacements for natural lipids in bread baked from defatted wheat flour

Petroleum ether (PE) extracted 1.00% total free lipids (0.70% nonpolar and 0.30% polar) and 2-propanol (PrOH) extracted 1.36% total free and bound lipids (0.73% nonpolar and 0.63% polar) from wheat flour; the lipid fractions were characterized by thin layer chromatography. PE- or PrOH-defatted flours were baked after reconstitution with total, nonpolar, or polar wheat flour lipids; or with equivalent amounts of nonionic sucrose monopalmitate (SMP), ethoxylated monoglycerides (EMG) — each with a hydrophile-lipophile balance (HLB) of 14.0 or anionic sodium stearoyl-2-lactylate (SSL) — with an HLB value of 9.0. Defatted flours supplemented with surfactants alone or in combination with wheat flour lipids were used in bread with no-shortening and with 3%-shortening. The importance of the polar flour lipids in breadmaking was verified. The lipids in wheat flour were essential for maximizing the beneficial effects of shortening on breadmaking quality. Nonionic SMP or EMG completely replaced both PE-extractable wheat flour free total lipids ( or their non-polar or polar fractions) and 3% shortening; nonionic surfactants with high HLB were better than the anionic SSL for replacing free flour lipids. No surfactant completely replaced unfractionated PrOH-extracted lipids (free + bound) and shortening or total polar flour lipids (free + bound). All surfactants, especially anionic SSL, added with PrOH-extracted polar lipids improved the overall bread-making properties of the PrOH-defatted flour both in the absence and in the presence of shortening. Presented at the AOCS Meeting, New York, May 1977     

Engaging with Marginalised Groups in Public Open Space Research: The Potential of Collaboration and Combined Methods

This paper discusses methodological dilemmas that were encountered, and strategies used to overcome them, in the Viewfinder project that was undertaken in 2004 in Sheffield, UK. The project investigated refugees’ perceptions and experiences of urban public open space in the UK. Through partnership with a 12-week, accredited photography training course and visits to public open spaces, the research combined visual, experiential, participatory and longitudinal approaches. This paper discusses the success of these in relation to three aims: (1) generating a research situation of open communication; (2) collaborating with non-academic partners; and (3) creating mutual benefit. The research identifies methodological techniques that have potential for engaging marginalised groups in landscape and planning research and in consultation practice.     

Data Processing for City Planning

In city planning, data-processing machines permit the rapid handling and summarization of data in housing, renewal, land use, transportation, and basic urban research. Electronic computers. specifically, are exciting because they offer a means of solving complex city planning problems, especially in forecasting land use and travel demand.

For most planning operations punched card data processing is superior to other processes. The functions of these machines are described herein and three examples of data processing are elaborated on. In future years, planning techniques may have to be altered considerably to take advantage of the potentials of data processing.     

The housing project,spatial experimentation and legal transformation in mid-twentieth century New York City

It is on the grounds of ‘eminent domain’ and in the context of the great urban transformations that the city of New York underwent through the twentieth century that so much criticism is launched at urban actors such as Robert Moses. Blight often constituted the ground of legitimacy for the use of eminent domain. Blight is often condemned for its definitional ambiguity by both legal and urban historians. Yet if it is considered at the intersection of urban spatial reasoning’s experimentation with the size of the neighbourhood in relation to the housing project, and at the point where it collides with legal argument and jurisprudential challenge around the notion of public benefit, it is possible to see an incredible productivity at work in the notion of blight. This paper argues that it is in fact the instrumentality of this definitional ambiguity that galvanises a broad and diverse dispute around housing. Rather than simply reflecting legal change, here the typological and diagrammatic spatial experimentation at work in the coming-into-form of the housing project can be seen iteratively to nudge transformation in legal and constitutional definition. This suggests a quite different kind of directed and specific material politics than that typically attributed to architecture’s disciplinary skill set.     

A NOVEL PASSIVE DUAL ENERGY RECOVERY SNUBBER FOR HIGH POWER GTO CONVERTERS

A novel passive dual energy recovery snubber circuit is presented where energy trapped in the snubber inductor and capacitor is recovered into the both DC rail and load, without any active devices or resistors. The maximum over-shoot voltage on the switch is fixed, peak switch current is low, circuit reset is fast and the operational range of load current is wide. This circuit is suitable for use in high frequency, single ended power gate turn-off (GTO) thyrister choppers. Main design equations, some simulations and practical results are included.     

Combustion of oil palm stone in a pilot-scale fluidised bed reactor

Biomass is being generated in vast amounts from oil palm plantations particularly in developing countries such as Malaysia, Thailand and Indonesia. Oil palm stone (OPS) is currently considered a waste material and has not previously been considered for energy purposes. The main objective of this study was to investigate the thermochemical conversion of OPS in a pilot-scale fluidised bed combustor. The net heating value of OPS was 24.93 MJ/kg. The effect of primary air flowrate and initial bed temperature were the main parameters investigated. The bed and bed's surface temperature were found to decrease as the primary air flowrate increased. In all tests CO emissions were less than 0.2%. The emissions of SO₂ and HCl ranged from 0.02 ppm to 0.05 ppm, significantly below the permitted levels set by legislation. Stable combustion was observed at a bed temperature of 950 °C. The most abundant elements found in the ash were Al, Ca, Fe, K, Mg, Mn, P, S and Si. However, due to the temperature regime used in the study fouling would not be an issue.     

Numerical Optimization of an Active Voltage Controller for High-Power IGBT Converters

Feedback control of insulated gate bipolar transistors (IGBTs) in the active region can be used to regulate the device switching trajectory. This facilitates series connection of devices without the use of external snubber networks. Control must be achieved across the full active region of the IGBT and must balance a number of conflicting system goals including diode recovery. To date, the choice of control parameters has been a largely empirical process. This paper uses accurate device models and formalized optimization procedures to evaluate IGBT active voltage controllers. A detailed optimization for the control of IGBT turn-on is presented in this paper