A Screen Magnifier Using “High Level” Implementation Techniques

This paper presents the architecture of, and the techniques used to build, a screen magnifier for visually impaired people that uses the "high-level" features of the Microsoft Windows operating system. The magnifier uses information from the Desktop Window as its source and overlays this with a topmost, transparent, layered window that contains the magnified image. Issues concerning cursor enlargement, tooltip suppression, and focus tracking are discussed. A stable magnifier results that does not need to use the "dirty" low-level techniques that are typically used to build screen magnifiers. The only known problem of the magnifier is that it fails to suppress the original, unmagnified cursor of the few applications that use custom cursors     

An investigation into formatting and layout errors produced by blind word-processor users and an evaluation of prototype error prevention and correction techniques

This paper presents the results of an investigation into tools to support blind authors in the creation and checking of word processed documents. Eighty-nine documents produced by 14 blind authors are analyzed to determine and classify common types of layout and formatting errors. Based on the survey result, two prototype tools were developed to assist blind authors in the creation of documents: a letter creation wizard, which is used before the document is produced; and a format/layout checker that detects errors and presents them to the author after the document has been created. The results of a limited evaluation of the tools by 11 blind computer users are presented. A survey of word processor usage by these users is also presented and indicates that: authors have concerns about the appearance of the documents that they produce; many blind authors fail to use word processor tools such as spell checkers, grammar checkers and templates; and a significant number of blind people rely on sighted help for document creation or checking. The paper concludes that document formatting and layout is a problem for blind authors and that tools should be able to assist.     

A modified urea based NP fertilizer: urea-TSP-MAP combinations

Applying urea with acidic phosphate fertlizer increases urea fertilizer efficiency by reducing ammonia volatilization and toxicity to crop from urea hydrolysis. However, urea and triple superphosphate (TSP) are not recommended to be cogranulated because blends might become wet and sticky. Monoammonium phosphate (MAP) is a less acidic P source than TSP, but is compatible with urea. The objective of this study was to evaluate compound NP fertilizer products made from MAP and TSP combinations as P sources with urea. Fertilizer mixtures were pelletized from commercial urea, TSP and MAP with different N:P₂O₅ ratios and MAP/TSP combinations. Moisture changes during storage, pH of fertilizer solutions, and ammonia volatilization from surface applied fertilizer pellets were measured. Using MAP with TSP in urea-P mixtures reduced moisture increases during storage. Increasing MAP in urea-TSP-MAP combinations increased fertilizer solution pH by over 1 unit as the MAP/TSP-P₂O₅ ratio increased from 0/100 to 100/0. Adding MAP as 50% of P in urea-MAP-TSP mixtures at 3:1 and 1.5: (N:P₂O₅) ratios reduced ammonia loss from urea 50% to 60% compared to urea alone; and ammonia loss was similar to that of urea-TSP combinations. A urea-TSP-MAP fertilizer combination could make efficient use of urea-N by crops by reducing ammonia loss from urea hydrolysis.     

Controlling mouse pointer position using an infrared head-operated joystick.

This paper describes the motivation for and the design considerations of a low-cost head-operated joystick. The paper briefly summarizes the requirements of head-operated mouse pointer control for people with disabilities before discussing a set of technological approaches that can be used to satisfy these requirements. The paper focuses on the design of a head-operated joystick that uses infrared light emitting diodes (LED's) and photodetectors to determine head position, which is subsequently converted into signals that emulate a Microsoft mouse. There are two significant findings. The first is that, while nonideal device characteristics might appear to make the joystick difficult to use, users naturally compensate for nonlinearities, in a transparent manner, because of visual feedback of mouse pointer position. The second finding, from relatively informal, independent trials, indicates that disabled users prefer a head-operated device that has the characteristics of a joystick (a relative pointing device) to those of a mouse (an absolute pointing device).     

The influence of formula modifications and additives on ammonia loses from surface-applied urea-ammonium nitrate solutions

Urea-ammonium nitrate (UAN) solution fertilizers are subject to N loss through ammonia (NH₃) volatilization. This loss may be reduced by manipulation of the proportion of urea and by use of additives to reduce urea hydrolysis or increase fertilizer solution acidity. This research was design to study the effect of urea proportion in UAN solutions, added ammonium thiosulfate (ATS), and aquechem liquor (an industry by-product) on NH₃ loss from N solutions surface-applied to a range of agricultural soils.NH₃ volatilization from urea (U), ammonium nitrate (AN), and UAN solutions surface-applied on six eastern Canadian soils was investigated. Ammonia loss from urea solutions ranged from 23 to 55% of the applied N. Increased AN-N in UAN solutions caused a reduction of NH₃ loss greater than the reduction in urea. Less volatilization was observed with N solutions of higher acidity. This effect was more pronounced on a sandy soil than on clay soil.When ATS was added to UAN solution, a further reduction of NH₃ losses was observed. This reduction ranged from 12 to 23.5% in Dalhousie clay and Ste. Sophie sand soils, respectively. Addition of aquachem liquor (AqL) to the UAN solution did not consistently reduce NH₃ loss.Supported by a grant from the Natural Sciences and Engineering Research Council of Canada, and Nitrochem Inc., Canada.     

Automated Braille production from word-processed documents

This paper describes a novel method for automatically generating Braille documents from word-processed (Microsoft Word) documents. In particular it details how, by using the Word Object Model, the translation system can map the layout information (format) in the print document into an appropriate Braille equivalent     

A modified Perkins Brailler for text entry into windows applications

In this paper, we describe how a Perkins Brailler can be adapted so that it can function as a keyboard to a personal computer. The paper describes the earlier work of others and the hardware and software of our system and concludes with indications of how the system may be improved.     

Volatilization of ammonia from urea-ammonium nitrate solutions as influenced by organic and inorganic additives

Fertilizers containing urea can suffer from nitrogen (N) loss through ammonia volatilization, resulting in reduced effectiveness of the fertilizers. The loss of N may be reduced by use of organic or inorganic additives.Laboratory experiments were conducted on surface soil samples (0–15 cm) from two agricultural soils (St. Bernard and Ste. Sophie) to determine the impact of ammonium thiosulfate (ATS), boric acid, and a humic substance from leonardite, on NH₃ losses from surface-applied urea-ammonium nitrate (UAN) solutions. Experiments were carried out using moist soil samples in closed containers. Evolved NH₃ was carried out of the containers and trapped in boric acid solution using an ammonia-free humidified air flow.Total NH₃ losses in these experiments ranged from 12.1 to 21.3% of the N applied. The reduction in NH₃ volatilization (expressed as % of added N) due to additives ranged from 13.6 to 38.5% and 3 to 36.3% in St. Bernard and Ste. Sophie soils, respectively. More NH₃ volatilized from the boric acid or humic treated UAN solutions than from ATS-UAN solutions.Boric acid, ATS, and the humic substance, all significantly reduced urea hydrolysis in both soils in comparison to the untreated UAN solution. Further, the humic substance and boric acid treatment induced significant reduction in NO₃-formation. The results suggest that humic substance and to a lesser extent boric acid may function as urease and/or nitrification inhibitors. ATS treatment, particularly at higher levels increased NO₃-formation in both soils. The reason for this increase in nitrate formation is not clear.     

A screen magnifier using "high level" implementation techniques.

This paper presents the architecture of, and the techniques used to build, a screen magnifier for visually impaired people that uses the "high-level" features of the Microsoft Windows operating system. The magnifier uses information from the Desktop Window as its source and overlays this with a topmost, transparent, layered window that contains the magnified image. Issues concerning cursor enlargement, tooltip suppression, and focus tracking are discussed. A stable magnifier results that does not need to use the "dirty" low-level techniques that are typically used to build screen magnifiers. The only known problem of the magnifier is that it fails to suppress the original, unmagnified cursor of the few applications that use custom cursors.