WorldCat Identities

Harper, S. A.

Overview
Works: 12 works in 13 publications in 2 languages and 27 library holdings
Genres: History 
Roles: Composer, Author
Classifications: HE244.Z7, 380.5094282
Publication Timeline
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Most widely held works by S. A Harper
Information for self-reliance and development : a policy framework for libraries and allied information agencies for Namibia( Book )

2 editions published in 1997 in English and held by 15 WorldCat member libraries worldwide

Inventar der Akten des kaiserlichen Bezirksamts Warmbad, 1899-1915 by S. A Harper( Book )

1 edition published in 1973 in Afrikaans and held by 2 WorldCat member libraries worldwide

Inventar der Akten des kaiserlichen Distriktsamts Zessfontein by S. A Harper( Book )

1 edition published in 1974 in Afrikaans and held by 1 WorldCat member library worldwide

Inventar der Akten des kaiserlichen Bezirksamts Swakopmund, 1892-1912 by S. A Harper( Book )

1 edition published in 1975 in Afrikaans and held by 1 WorldCat member library worldwide

IMPROVED PULSED PHOSPHORS( Book )

1 edition published in 1966 in English and held by 1 WorldCat member library worldwide

Astudy was made of electroluminescent (EL) materials and procedures for the purpose of evaluating and improving their performance under pulsed excitation conditions. Zinc sulfide and zinc sulfoselenide powder phosphors in plastic dielectric mediums were studied under pulsed excitations in the form of sinusoidal ac bursts, rectangular dc pulses and dc bursts (groups of high frequency dc pulses). Optimum values of the integrated light output while maintaining adequate arcing strengths of the EL layers are given below for a duty cycle of 0.1%. The repetition rate was constant at 30 pulses or bursts per second. Excitation with 150 kc bursts yielded integrated light outputs of about 10 ft .L. while the maintenance (hours to one-half of initial brightness) was 1300 and 3500 hours for two different phosphors. About 5 ft. L. of integrated brightness was obtained from dc pulsed excitation and maintenance values of several thousands of hours. Measurements with dc bursts indicated 7 to 8 ft. L. as the optimum values of the output with this method of excitation. (Author)
The Dynamics of Salt Marsh Development in South-East Lincolnshire by S. A Harper( Book )

1 edition published in 1976 in English and held by 1 WorldCat member library worldwide

IMPROVED ELECTROLUMINESCENT PHOSPHORS( Book )

1 edition published in 1964 in English and held by 1 WorldCat member library worldwide

The report describes the reeresults ofo of sstudies on the pererformannce characteristics of electroluminescent (EL) zinc sulfoselenide phosphor powders in plastic dielectrics. The objective of the investigation was to develop phosphors which yielded exceptional brightness under pulsing conditions as well as improved performance under continuous excitation at both high and low voltages. Phosphors were evaluated under short bursts of AC (pulsed) excitation with the frequency within the pulse varying from 20-100kc. About 5000 ft. L. of brightness was obtained during pulse intervals and maximum bursts were measured close to 10,000 ft. L. Under continuous excitation at 420 cps, three selected phosphors emitting in the green-yellow, light yellow and deep yellow region displayed initial brightneessssentthgiightnesses of about 97, 60 and 33 ft. L. The maintenance (hours to one-half of initial brightness) of these same layers was about 2200, 4500, and 8000 hours respectively. Phosphors were also evaluated in thin low voltage layers at 25 and 50 volts. At 1500 cps, the brightnesses varied from 2.5 to 24 ft. L. while the maintenance was in the range of 150 to 500 hours. (Author)
Inventar der Akten des kaiserlichen Bezirksamtes Karibib, 1894-1915 by S. A Harper( Book )

1 edition published in 1974 in Afrikaans and held by 1 WorldCat member library worldwide

Inventar der Akten des kaiserlichen Distriktsamts Gobabis, 1898-1915 by S. A Harper( Book )

1 edition published in 1974 in Afrikaans and held by 1 WorldCat member library worldwide

Inventar der Akten des kaiserlichen Distriktsamts Maltahöne, 1894-1915 by S. A Harper( Book )

1 edition published in 1974 in Afrikaans and held by 1 WorldCat member library worldwide

Transport and industry in South Yorkshire by Paul Henry Abell( Book )

1 edition published in 1977 in English and held by 1 WorldCat member library worldwide

Inventar der Akten des kaiserlichen Bezirksamts Omaruru, 1894-1915 by S. A Harper( Book )

1 edition published in 1974 in Afrikaans and held by 1 WorldCat member library worldwide

 
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Audience level: 0.85 (from 0.77 for Informatio ... to 0.99 for IMPROVED E ...)

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