Sealed Windows Research Articles

Fiberoptic in-vessel viewing system for the International Thermonuclear Experimental Reactor

A viewing system was designed and a prototype realized for the in-vessel inspection of the International Thermonuclear Experimental Reactor. The viewing is based on the line scanning principle, and the system consists of ten identical units installed on top of the reactor at 36° intervals. Each device contains a laser, beam steering mirrors, and viewing probe with insertion mechanics. The probe has an outside diameter of 150 mm and a length of 14 m. The illumination design applies frequency-doubled Nd: yttrium–aluminum–garnet lasers whose beams are guided through hermetically sealed windows into the vacuum vessel. The diffuser optics creates a vertically oriented light stripe onto the vessel surface that is viewed by the imaging optics, consisting of 16 modules altogether covering horizontal and vertical field-of-views of 2° and 162°. The optical images are transferred to charge coupled device cameras via coherent fiber arrays. The multifocus design uses stacked fiber rows whose ends are assembled into different axial positions. The viewing probes rotate at a constant angular speed of 1°/s and pictures are taken at 0.01° intervals. The complete picture of the vessel interior is generated in 6 min producing 5.8×109 image pixels. The image processing and analysis of possible defects in the vessel surfaces are performed off-line after the viewing procedure. A full-scale prototype of the viewing probe was constructed to demonstrate the feasibility of the design. Its illumination optics utilizes a diffractive optics element that transforms the collimated input beam into a rectangular output lobe with uniform intensity. The prototype has horizontal and vertical imaging optics field-of-views of 2° and 12°. The test results showed that the prototype can take pictures of good quality applying a continuously rotating probe having an angular speed of 0.08°/s. Under optimum conditions, the minimum resolvable feature size at a 3 m distance is smaller than 1 mm, which satisfies the requirement specification. Further development is needed to increase the illumination power to improve the imaging speed and to develop linear fiber arrays that are compatible with the vacuum and high-flux radiation environment of the primary vacuum vessel.

Comparative thermal performance of new and old houses

The commitment to reduce energy consumption in buildings has focused attention on improving thermal insulation by employing measures such as the use of insulated cavity walls, double glazed sealed windows and insulated lofts. The energy consumption and thermal performance of two different types of house, an old and a new detached house are compared. Attention was focused on the living areas. The rate of air in-flow as determined by tracer gas, the air velocity and temperature distribution at two levels of 0.15 and 1.2 m were measured. The results show that in the new house the temperature difference between a seated person's head and ankle is more than 3 °C. This difference is increased when the central heating is switched on. In both houses the gap under the entrance door is large and contributes to a high internal air velocity. Despite the inadequacy of the installed air ventilator, the energy efficiency of the new house is demonstrated.

Prevalence of the sick building syndrome symptoms in office workers before and six months and three years after being exposed to a building with an improved ventilation system.

OBJECTIVE: The prevalence of symptoms associated with the sick building syndrome (SBS) has recently been shown to decrease by 40% to 50% among office workers six months after they were...

Prevalence of the sick building syndrome symptoms in office workers before and after being exposed to a building with an improved ventilation system.

To find if the prevalence of symptoms associated with sick building syndrome decreased among office workers after moving to a building with improved ventilation (after controlling for potential confounders). Workers in five buildings in 1991 all moved in 1992 into a single building with improved design, operation, and maintenance of the ventilation system. All buildings had sealed windows with mechanical ventilation, air conditioning, and humidification. Workers completed a self administered questionnaire during normal working hours in February 1991 and February 1992. The questionnaire encompassed symptoms of the eyes, nose and throat, respiratory system, skin, fatigue, headache, and difficulty concentrating, personal, psychosocial, and work related factors. During normal office hours of the same week environmental variables were measured. The study population comprised 1390 workers in 1991 and 1371 workers in 1992 who represented more than 80% of the eligible population. The prevalence of most symptoms decreased when workers moved to the new building: skin (54%), respiratory system (53%), nose and throat (46%), fatigue (44%), headache (37%), eyes (23%). These findings were all significant and remained generally similar after controlling for personal, psychosocial, and work related factors. Furthermore, more than 60% of workers symptomatic in 1991 were asymptomatic in 1992 for all types of symptoms. In contrast, less than 15% of workers were asymptomatic in 1991 but symptomatic in 1992 for all types of symptoms. In this study, the prevalence of most symptoms usually associated with the sick building syndrome decreased by 40% to 50% after workers were transferred to a building with an improved ventilation system. The results show that it is possible to diminish the prevalence of symptoms associated with the sick building syndrome among office workers occupying a building with mechanical ventilation, air conditioning, and sealed windows.

Rejuvenating an aging microfilm collection

Sleep is head of Serials Depar tment at Brock Univers i ty Library , St. Catharines, Ontario, Canada. T w e n t y f i v e years ago when Brock Universi ty was established, the l ibrary's Serials Department began to build a mic roform collection of serials backfile. By May 1988 this collection numbered 8,959 rolls. All were 35mm and non-sprocked film. In the early years only silver halide was purchased, but with shrinking budgets the cheaper vesicular or diazo film was acquired. The film was stored in supposedly near -opt imum conditions. The building was new with hermetically sealed windows and the Sixties' stateo f the -a r t heating, air condit ioning, and ventilation systems, but with no bui l t in humidi ty controls. In reality the building's air circulation, heating, and condit ioning developed a variety of problems over the years, and the adjustments made to lower the temperature to accommodate the national concern over energy conservation in the 1970s only acerbated the situation. Thus, the building in which the fi lm is housed never did meet even Francis Spreitzer's broad range tempera ture and /o r humidi ty standards: 50-70 degrees Fahrenhei t at relative humidi ty of 30-50 percent with no more than a 5 percent f luctuation over a 24-hour period. 1 The actual microf i lm cabinets are the standard steel cabinets with an enamel finish as recommended in Micro form Review ~ and purchased f rom a recognized supplier. The individual roll remains in the container, which is presumably ac idf ree , z provided by the fi lm manufacturer . To avoid the mismatching of a roll of one title with a box of another title, labels (which are not recommended) 4 initially were applied to the leaders to ident i fy the film, but in recent years f i lm marking pens have been used. In the cabinets the rolls are interfi led, regardless of fi lm type, in one alphabetical sequence for easy pa t ron / s ta f f use. The cabinets are situated near the microf i lm readers in the open stacks to

Thermal stresses in double-glazed windows

Using finite elements, the authors studied temperatures and thermal stresses in 1.41 m wide by 2.12 m high sealed double-glazed windows of 6-mm glass with a 12-mm air space between the panes. The purpose was to find factors significantly influencing thermal stresses. Three types of commercially used windows subject to winter conditions (day and night) were analysed: both panes clear glass; outer pane heat absorbing and inner clear; and outer clear with a metallic film on its room-side surface and inner clear. A sensitivity analysis included variations in size of window, gasket and sealant stiffnesses, frame absorption, solar heat flux, exterior air film conductance, and outdoor air temperatures (−5 and −25 °C). Further, the influence of horizontal and vertical shadows was studied. For the calculation of thermal stresses, the authors found that the windows could be analyzed pane by pane rather than as a three-dimensional structure. Solar radiation and particularly shadows had a major influence on thermal stress, while window size and aspect ratio did not. A case study in which the predicted temperatures were compared with those measured by Sasaki in 1974 showed good agreement and indicated that a simpler steady-state rather than transient thermal analysis gave a close estimate of the temperature difference between the centre and edges of panes for design against thermal breakage. Key words: window breakage, thermal stresses, glass temperatures, shadows, double-glazing, finite elements.

New outlook on window manufacture

Supaglide, a leading manufacturer of sealed unit double glazed aluminium windows and doors, is a good example of where automation of the sealant application process has been highly effective. Although not using robots, the production line is able to handle, at random, a complete variety of sizes of sealed units with varying internal cavities.

HeNe Parallel Plate Laser Development

A parallel plate format is used for fabricating “hard” sealed HeNe lasers. The new packaging geometry and construction process are suitable for large scale manufacturing. Cut plate, molded plate, and folded beam lasers have been built and tested. Several changes from conventional lasers, such as evaporated film cathode and anode, square cross section bore, glass sealed Brewster windows, and “soft” glass bore materials, are discussed. The power output capability, measurements of gain and loss parameters, and the reliability of these lasers are also considered.

Physisorptionsmessungen bei hohen temperaturen mit hilfe der IR-spektroskopie: Eine neue messzelle und ihre anwendung auf die adsorption von benzol auf γ-aluminiumoxid

A measuring cell was constructed with sealed Si windows and a very short pathlength of light in the gas phase. The cell allows pretreatment temperatures of the adsorbent of 1000 K and measuring temperatures up to 650 K. The cell was used to determine the adsorption isotherm of benzene on γ-alumina at 473 K.

Image Converter for Thermal Radiation*

The development of the phothermionic image converter is described, a device which reproduces scenes by virtue of differences in their thermal radiation. The method uses the principle of projecting a temperature image on a free multilayer film about 0.05 μ thick which contains a photosurface with thermally sensitive yield. Image conversion is achieved by probing the temperature distribution with a flying light spot and displaying synchronously the thermally modulated photocurrent on a monitor. Section 1 discusses the limits of temperature imaging. Under idealized shielding conditions, the relative temperature distributions in the image assume a very simple and general relationship to that of the object, e.g., are equal in radiation equilibrium. Practical heat exchange processes will present other signal limitations which, in combination with the random noise inherent in any conversion process, determine the system performance. Section 2 deals with the experimental work of searching for, and improving on, the phenomena on which the operation of the image converter is based. This includes theory and experiments on temperature sensitive photoelectric yields and on the electrical and optical properties of thin films. Certain components such as sealed crystal windows, cooled radiation shields, and free thin films had to be developed for the image tube. Several models were built and accommodated by suitable optical and electronic systems. When completed, the device had television bandwidth and motion portrayal capabilities and the ability to detect, or image, temperature differences of 10° to 50°C.

Mechanically sealed beryllium windows for permanently evacuated X-ray tubes

Mechanically sealed beryllium windows for permanently evacuated X-ray tubes