Daylight opening

Daylight opening n. The clearance between two platens of a molding press when in the open position. 

It is a disadvantage of all photomultipliers that the photocurrent is not completely proportional to the strength of illumination. Further, the photocurrent must not exceed 10 A or the photomultiplier becomes fatigued. Daylight switches are incorporated into some scanners for this reason in order to prevent over-illumination of the detector when the sample chamber is opened. 

Virtually no mnning cost Self-regulation (flow rate increases with heat load) Low maintenance cost Provides daylight when open (roof vent) Psychological appeal of clear sky (roof vent) Easy installation... 

A technique of press curing in which the moulds are serviced while the press is closed. For example, in a two daylight press operating on a 60 minute cure, the press will be opened at 30 minutes and the mould from platen 1 removed and replaced with another mould loaded with the moulding blank. At the end of a further 30 minutes the procedure is repeated for platen 2, and the cycle of operations continued. 

Optical detectors shall be used in more open configurations where ressure buildup due to the incipient explosion is limited. Optical etectors shall not be used where high dust concentrations limit the reliability of the suppression system. Both uv and ir detectors are available for optical detection. The use of daylight-sensitive sensors shall be avoided to avoid spurious activation. The sensor shall be mounted such that the angle of vision allows it to cover all the protected hazard area. The performance of an optical detector will also be affected by any obstacles within its vision, and this shall be overcome by the introduction of more detectors. Optical detectors shall be fitted with air shields to keep the optical lens clean. 

Photolysis at 254 nm of phenylbutazone (220) in aqueous solution raised to pH 8 to 9 with sodium hydroxide gave a mixture of ring-opened products. Reisch etal. identified samples of aniline, the malonamides (221) and (222) and the 2-oxohexanamide (225). When the solution was basified with diethylamine, the amino diamide (223) was produced in addition to (222) and (225). In methanol solution the malonamides (221) and (224) were obtained [132]. In an older study by Pawelczyk and Wachowiak, a 20% solution (pH 10.5) of phenylbutazone sodium was kept in a clear glass bottle in diffused daylight for 2 years. 

An important group of conjugated diene/triene systems are those in the vitamin D series. The key reactions in the commercial manufacture of vitamin D (and probably also in its formation in skin exposed to daylight) are a photochemical, conrotatory electrocydic ring-opening in the provitamin, and a thermal 1.7-shift of hydrogen in the previtamin so formed (2.23). High conversions to the vitamin are not normally possible because all three species absorb appreciably at the... 

Ring opening by photolysis also occurs in the oxadiazoline ring. Srivastava and Clapp109 noted that a simple rearrangement [Eq. (44)] of 4-/3-ethoxyethyl-3-methyl-5-p-nitrophenyl-l,2,4-oxadiazoline to a substituted amidine (50) took place on a bench top in ordinary daylight or... 

Easy is the descent of Avernus Night and day the portals of gloomy Dis stand open but to reverse your step and to win again the daylight—that s labour, that s hard work, Virgil, Aeneid, vi, 126. 

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