1,727 research outputs found
Malaria in Infancy
A CAJM article on malaria fever in small children in Africa of the 1950's.To the epidemiologist malaria in the infant is of two-fold interest. In highly "malarious" areas it is the first attacks, occurring during the early years of life, which build up a relative immunity at the cost of considerable death and disability. Secondly, the rate of infection in the infant serves as a useful yardstick of transmission and is widely used as a measure of the success of control.
The effects of malaria are extremely variable and are often more obvious in the areas where transmission is less intense
Object Permanence in the Raccoon (Procyon Lotor)
Two studies are conducted to test object permanence in infant and adult raccoons. The raccoon (Procyon lotor) is an omnivorous generalist known for its primate-like intelligence, but has never been given object permanence testing. In Study 1, infant raccoons (kits) of 12 and 16 weeks failed single visible displacement tasks conducted with either two or three cups as hiding places. Therefore, unlike other carnivores that have been tested, raccoon kits do not appear to have developed Stage V object permanence by the age of weaning or age of independence from the mother. Adult raccoons in Study 2 performed above chance on single visible displacements, but did not pass multiple visible displacements, invisible displacements, transpositions and rotations. These results suggest that the raccoon is limited to representing visible displacements, and is therefore a Stage V species
A critical survey of the materials and techniques of Charles Henry Sims RA (1873-1928) with special reference to egg tempera media and works of art on paper
This thesis collates and provides new knowledge about the working practices and dissemination of materials and techniques of a leading Edwardian painter. Charles Sims RA (1873-1928) represents a neglected body of British artists who were responding to and assimilating certain new tendencies within early modernism yet at the same time were conscious and respectful of traditional practices and training methods. The study makes consistent reference to the extensive studio archive at Northumbria University whose existence has provided a unique opportunity to map Sims’ own informal working notes and observations, against the retrospective account Picture Making (1934) by his son, and instrumental and technical analyses performed on some works.
The significance of this specific period in relation to the development of new materials and techniques, and the role instruction manuals and teaching played in developing Sims' stylistic and at times thematic approaches to practice are also discussed. Of particular interest are those which focus on drawing, watercolour and egg tempera techniques, media which perfectly suited Sims' temperament and arguably featured in and formed his best works.
The thesis also aims to compare Sims' working practices with those of his better known contemporaries such as Augustus John, Philip Wilson Steer, William Orpen (all from the Slade) as well as members of the Tempera Revival movement. by crossreferencing reports held in national and international collections with hitherto unseen material. As a consequence the research will have a much wider application beyond the field of conservation, and will illuminate early 20th century artistic inheritance and intent
The Development of the CONDUIT Advanced Control System Design and Evaluation Interface with a Case Study Application to an Advanced Fly by Wire Helicopter Design
This report details the development and use of CONDUIT (Control Designer's Unified Interface). CONDUIT is a design tool created at Ames Research Center for the purpose of evaluating and optimizing aircraft control systems against handling qualities. Three detailed design problems addressing the RASCAL UH-60A Black Hawk are included in this report to show the application of CONDUIT to helicopter control system design
Modern machine–made washi and the implications for contemporary conservation practice
Japanese paper, commonly known as washi, is an important commercial commodity and intrinsic to both Western and Eastern conservation techniques due to its strength, transparency and excellent ageing properties. With modern technology and the slow decline in hand-made papermaking, much of the paper produced in Japan today is machine made-essentially a hybrid of traditional Asian techniques and European influences. How this paper is made and the materials used in its construction are often a closely guarded secret for obvious commercial reasons. Newly developed sizing agents, chemical treatments and the substitution of high quality bast fibres for inferior wood furnishes, are a concern for the conservation profession in regards to possible changes to the papers long- term behaviour, and immediate physical alterations due to the fibres strong orientation towards the machine-grain direction. The article collates and compares the materials and methods used in producing hand and machine-made washi and considers the potential risks and benefits resulting from current innovations.
The study goes into the heart of paper production and distribution in Japan and as a consequence provides new knowledge to Western audiences. It also serves to clarify certain key technical terms which are currently open to a wide variety of interpretations
The development of Northumbria University collections, materials and conservation research archive
This paper discusses issues that are common to conservation archive collections in the UK. It focusses on Northumbria University, where a significant number of artworks on canvas and paper, diaries, sketchbooks, artist materials, technological and scientific outputs, reconstructions, samples, photographs and digital images have been amassed over several decades in support of education and research. Although this resource is available to students and scholars, physical access is impeded by the diversity of locations where each item is held and the dependencies retrieval and supervision has on staff time. Our concern is that this valuable resource is underused because of the lack of electronic records, and whilst a few noteworthy artworks and materials are internally recorded, none are linked to heritage or educational networks. We anticipate that Northumbria is just one amongst many organisations with similar issues and that it is possible to plan for a more unified system where conservation archives and related research outputs are linked to a wider network
Airflow to disperse refrigerant leaks from hydrocarbon refrigeration systems
Whilst R290 is currently used to a limited extent in room air conditioners there is a desire for wider application due to its excellent performance and negligible global warming potential. The product standard IEC 60335–2–40 specifies requirements to limit the allowable refrigerant charge in such a way that it obstructs the wider use of R290. Airflow of an indoor unit can be used to dilute a refrigerant leak, enabling substantially greater charge quantities to be used. A numerical model based on entrainment theory was developed and supported by analysing the behaviour of experimentally simulated releases under various conditions with indoor unit airflow. The work determines the minimum airflow rate necessary to prevent formation of a flammable concentration within the room. Further, the work includes determination of appropriate response time and leak rate to initiate airflow once a leak has begun. The developed methodology can equally be applied to commercial refrigeration units and other flammable refrigerants
Hydrocarbon refrigerant charge limits for quiescent rooms
Concentration measurements and analysis have been used to develop new methodology for estimating the allowable charge limit (ACL) of flammable refrigerants, particularly R290. Attention has been given to the impacts of construction and dimensional characteristics of the RACHP enclosures, in particular the size and position of the openings, on the concentrations exiting the enclosure. Analysis of the data has shown that these are critical aspects that influence floor concentration and/or safe allowable refrigerant charge limits. Formulae have been proposed to estimate layer-volume heights and ultimately ACL. The results illustrate that current standard's ACLs are overly restrictive, especially for certain types of RACHP equipment
Assessment of factors affecting R290 concentrations arising from leaks in room air conditioners.
Currently R290 is used to a small extent in room air conditioners, such as split, portable and window types.
Products are limited to relatively small cooling capacities due to refrigerant charge sizes being constrained to
around 300 – 400 g, on account of maximum charge formulae within standards IEC 60335-2-40, ISO 5149-1
and EN 378-1. This is especially challenging in warm countries where the cooling load is greater and charge
sizes need to be larger. Work is underway to improve maximum charge size determination methods for a given
room size. As a contribution to this on going process, further research has been carried out to understand the
factors that affect development of flammable concentrations within roomsin event of a leak. Parameters related
to the characteristics of room air conditioners and installations have been investigated experimentally by
measuring R290 concentrations from releases and selected findings are described
Minimum airflow rates to dilute R290 concentrations arising from leaks in room air conditioners
Currently R290 is used to a limited extent in room air conditioners, such as split, portable and window types.
The product standard IEC 60335-2-40 currently specifies requirements to limit the charge of flammable
refrigerants in such a way that it obstructs the wider use of R290. This is particularly challenging in warm
countries where the heat load is greater and thus charge sizes need to be larger for a given room size,
inferring higher concentrations in the event of a leak. Relying on the airflow of an indoor unit can be used to
dilute a refrigerant leak and thus prevent flammable concentrations forming, despite the charge quantity
being substantially greater than that currently permitted in the current standard. Research has been carried
out to determine the minimum airflow rate from an air conditioner necessary to achieve sufficient dilution. A
numerical model based on entrainment theory was developed and supported by experimentally analysing the
behaviour of releases under various conditions with RACS airflow
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