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1.
《文物保护研究》2013,58(3):169-173
Abstract

A complete summary of equations for leakage of enclosures is given, including vapour diffusion through still air in openings, and infiltration of air/vapour/particulate mixture. Stack pressure due to temperature and relative humidity difference drives most infiltration. Experiments confirmed the diffusion and infiltration equations for small and medium-size enclosures. Leakage for a carefully made display case with ordinary materials has been reduced to the microbarometric limit of about 0·03 of an air change per day. Simplified tables and charts of leakage are given for 0·1, 1·0 and 10m enclosures, as a function of crack width, hole width, and wall permeability.  相似文献   

2.
Abstract

The objective of the study presented here was to determine the socio-cultural factors that enhanced the use and transfer of scientific information among agricultural scientists in south eastern Nigeria. The implications of some of these factors for agricultural development are highlighted.

Structured questionnaires were distributed to a stratified random sample of 300 scientists. Two hundred and ten (210) questionnaires were mailed while 90 were self-administered. Two hundred and forty-five (81·6%) usable responses were received and analysed. Data were also generated from interviews with selected members of the stratified random sample. Analyses focused on social and cultural factors of (1) motivation, (2) computer appreciation, (3) choice of media for research communication, (4) recipients of research communications, and (5) scientists' activities considered for assessment and reward. Frequency counts were the presentation techniques used to elucidate results.

Results showed that scientists were motivated more in the use and transfer of scientific information by social factors of self-development (53·3%) and job security (12·9%) than by social factors of scientific problem solution (19·6%) and intellectual contribution (12·6%).

Cultural factors of development in information technology (36·8%), adequate and relevant information resources (12·6%) and previous information attitudes (24·5%) also influenced scientists. Although five types of recipient groups of research communications were identified, the study noted that there was a disproportionately inadequate diffusion of research communications to two important groups of “national planners” and “external aid bodies”, who plan and finance agricultural development. Only 5% of scientists sent research communications to national planners and only 3·7% of scientists sent research communications to external aid bodies.

Strategies for assessing other quantifiable elements of productivity by scientists outside journal publications and for diffusing adequate scientific information to national planners and external aid bodies are deemed necessary.  相似文献   

3.
《文物保护研究》2013,58(4):289-303
Abstract

A tube-type passive sampling method has been developed and assessed for the quantification of formaldehyde (methanal) vapours in indoor air. The sampler was designed for use in museums where test sites often include small enclosures with low air movement. The procedure involves collection of formaldehyde vapours in a Palmes diffusion tube containing a paper support impregnated with an acidified solution of 2,4-dinitrophenylhydrazine (2,4-DNPH). After sampling, quantification of the trapped F-DNPH is achieved by high performance liquid chromatography (HPLC) analysis with UV detection at 350nm. To validate the procedure, permeation devices were used to generate formaldehyde-containing atmospheres, 81–2975ppb, in a 20dm3 chamber so that experimentally derived sampling rates could be calculated and compared with the theoretical value. Three 2,4-DNPH solutions were investigated to obtain an efficient and stable trapping solution. Best results were achieved with a 27mg.ml?1 solution of 2,4-DNPH which contained 4·5%v/v orthophosphoric acid. At 55% RH, and with low airflow in the chamber, the experimentally derived sampling rate of 1·34 ± 0·17ml.min?1 was in good agreement with the theoretically derived sampling rate of 1·36ml.min?1 The passive sampling method was repeatable and reproducible with RSD (relative standard deviation) values below 7%for long-term exposures at low air velocities.  相似文献   

4.
《文物保护研究》2013,58(2):100-106
Abstract

The paper discusses the methodology adopted for and the results derived from a pilot project to conserve the lead and lead alloy communion tokens in the collections of St Andrews University. For the project a new conservation process, ‘potentiostatic reduction’, was developed, involving reduction of the tokens at ?1·2V vs. SCE (saturated calomel electrode) in 0·5M H2SO4, The aim of the pilot project was to test the effectiveness of the new process in tackling a largescale conservation problem by observing its effects on a wide range of tokens made of various alloys and suffering from varying degrees of corrosion. The results of the pilot project indicated that potentiostatic reduction is as effective as standard electrolytic reduction. Since the new technique greatly reduces the time required for the conservation of individual artifacts, there are substantial savings in conservation costs.  相似文献   

5.
《文物保护研究》2013,58(3):175-182
Abstract

The Perkin-Elmer infrared microspectrometer consists of a basic, double-beam spectrometer M 13, on which a microscopical system model 85 with reflecting optics can be mounted. The microspectrometer can be used only for single-beam measurements. Pressed in a KBr-pellet, with a radius of 0·5 mm, the amount of sample of a pure material can be decreased to 2 μg. A sample with different paint-layers can be embedded in a wax with little infrared absorption and can be cut with the help of a microtome in slices with a thickness of 20 μ. Every paint-layer can be measured separately by means of an adjustable diaphragm in the microscope. A sample area of 37·5 ? 500 μ is sufficient to obtain an identifiable spectrum.  相似文献   

6.
《文物保护研究》2013,58(3):93-106
Abstract

During 1977–78, a conservation project was undertaken by the Federal Government of Canada to preserve the weathered hull of the HD-4, an experimental hydrofoil craft built at the laboratorie of Alexander Graham Bell in Baddeck, Nova Scotia. After achieving a world marine speed record of 70·86 m.p.h. (114·01 km.p.h.) in 1919, the craft was beached on the shore of a salt water lake. Forty years’ exposure to severe weathering caused wood rot, metal corrosion and the disintegration of the canvas covering. Due to the deteriorated condition of the craft and the loss of most of the external structures, complete restoration was not desirable or practical. The aim of the project was therefore, to stabilize the wooden hull, while preserving its weathered appearance.  相似文献   

7.
《文物保护研究》2013,58(1):49-58
Abstract

Black weathering layers on stone often contain iron. This is particularly true for the Turonian sandstones which were used extensively in architecture and sculpture in Saxony. In order to obtain more knowledge about the oxidic iron phases, samples were collected in the city of Dresden. Mineralogical and analytical characterization was provided for the black layers and the supporting stone. Material originating from Cotta and Posta stone was submitted to Mössbauer spectroscopy. After ample comparisons of Mössbauer parameters and evaluation of infrared spectra it was concluded that the predominant neogenic iron phase is not iron(III) oxide hydrite (ferrihydrite) Fe2O3·1·8H2O or jarosite KFe3(SO4)2(OH)6 or goethite α-FeO(OH) but a defectively ordered precursor of this last compound, characterized by different environments of the iron(III) ions. By the reducing action of organic matter, magnetite Fe4O4 is formed and this contains up to 45% of the iron present in a black layer.  相似文献   

8.
《文物保护研究》2013,58(2):128-132
Abstract

The effect of low oxygen atmospheres on all life stages of the powderpost beetle, Lyctus brunneus (Stephens), was investigated. Artificial diet blocks infested with immature stages of Lyctus brunneus were exposed to a low oxygen atmosphere (0·4% oxygen, balance nitrogen) at 30°C and 70% RH for varying lengths of time. Mortality counts for immature stages were based on the relative number of adult beetles emerging from the treated and untreated diet blocks. One hundred percent mortality was observed for eggs, larvae and pupae exposed to low oxygen atmospheres for six, eight and 12 days, respectively. Adult beetles similarly exposed to low oxygen atmospheres all died within three days.  相似文献   

9.
ABSTRACT

Sandstone is a common sedimentary rock that is easily carved due to its weakly cemented fine grains and relatively low strength. Therefore, numerous large-scale grottoes in China are made of sandstone. However, these sandstone cultural heritage structures are often seriously damaged due to temperature and humidity changes, air pollution, biodeterioration, and repeated dissolution and crystallization of soluble salts. In general, it is imperative that a consolidant capable of providing cohesion by infilling pores between the stone grains is synthesized. In recent years, it has been reported that using organic consolidation materials for sandstone protection comes with various negative effects, such as a short lifetime, poor compatibility, and preservation damage. Using inorganic consolidation materials to protect sandstone seems to be one of the research trends for the future. Herein, this paper introduces a permeable, inorganic magnesium-based material (MMH solution) for silica sand consolidation. To assess this consolidant, the paper investigates the influence of varying molar ratios of MgO:MgCl2·6H2O:H2O on properties such as penetration depth, consolidation weight, colour variation, and compressive strength. The results demonstrate that the molar ratios of MgO:MgCl2·6H2O:H2O can significantly affect the consolidation performance. Additionally, it is believed that the MMH solution of MgO:MgCl2·6H2O:H2O?=?5:1:16 can be successfully used for the consolidation of silica sand, as the cubic specimens’ surface micrographs show good compatibility between the consolidation product and sand grains. Experiments (i.e. weight loss rate and mineralogical compositions analysis) are performed to evaluate the cubic specimens’ water resistance properties after being immersed in water. Furthermore, the consolidation material’s failure mechanism as a self-sacrificing material is preliminarily analyzed. Results indicate that MMH solution is a promising conservation material that shows great potential for consolidating severely weathered sandstone.  相似文献   

10.
《文物保护研究》2013,58(4):284-286
Abstract

The widespread occurrence of thecotrichite, Ca3(CH3COO)3Cl(NO3)2·7H2O, in the museum environment is explained theoretically by construction and examination of its phase diagram. Thecotrichite formation was simulated in the laboratory to identify the key factors involved in its production. This efflorescence occurs on porous limestone or calcareous artefacts such as pottery, stored in wooden cabinets that generate acetic acid vapour. Salt production depends on the moisture content of the object and the concentration of acetic acid in its surroundings. Furthermore, for thecotrichite to form the artefact must contain soluble chloride and nitrate salts.  相似文献   

11.
《文物保护研究》2013,58(3):148-152
Abstract

Mineralogical changes which occur during the reaction of copper(II) chloride with carbonate in aqueous solution have been investigated, and compared with those involving copper(I) chloride, nantokite, CuCI, and copper artifacts coated with malachite, CU2CO3(OH)2 The reactions observed and the products obtained are seen to have implications with respect to the use of aqueous sodium carbonate solutions to stabilize archaeological copper objects. The frequent observation of the mineralogically rare species chalconatronite, Na2Cu(CO3)2·3H2O, on the surface of treated objects is readily explained by known reaction chemistry. Its formation can be minimized by washing the object after treatment.  相似文献   

12.
《文物保护研究》2013,58(3):165-184
Abstract

This study investigates the effects of a selection of alkaline reagents, including solutions, pastes and soap gels, used to remove an artificially aged mastic film applied over a primed canvas. Surface changes were examined using visible light and scanning electron microscopy (SEM). Ammonia, whether in solution or gelled with hydroxypropylmethylcellulose (HPMC), required a pH of 10 or higher to remove varnish at an appreciable rate, whereas ammonia in wax paste worked at pH 9. Soap gels based on deoxycholic acid (DCA) were effective at pH 9·5. The rate of removal increases significantly with the addition of benzyl alcohol, while anthracene-9-carboxylic acid (A9C) and 9-fluorenone-4-carboxylic acid (9FOC) soap gels of pH 7·9 worked quickly without the addition of alcohol. Where reagents with a pH of more than 9 were used, some erosion of the priming was observed under SEM. Examination of the topography of residual varnish after treatment and Fourier transform infrared spectroscopy (FTIR) measurements provided evidence in support of models for the mode of action of reagents and soap gels on aged varnish. Ammonia, whether in solution, gel or paste, removes varnish by fracturing on a multi-molecular scale; soap gels not -specifically tailored to remove the varnish act similarly. A9C and 9FOC gels remove the varnish by thinning from the upper surface without fracturing.  相似文献   

13.
ABSTRACT

Chalconatronite, Na2[Cu(CO3)]2·3H2O, is formed as a corrosion product when copper alloys are exposed to sodium carbonate solutions in the air. This also happens when metals come into contact with corroding soda glass which forms alkaline surface films in reaction with humidity from clean air. More often, substantial amounts of formaldehyde are present indoors which react to formate via the Cannizzarro reaction and accumulate over time in the films. Twenty cases of chalconatronite (including two mentioned in the literature) are reported as occurring on heritage objects with glass in contact with copper alloys: Baroque reliquaries with set glass gems, enamel on metal (sixteenth century and a modern replica of intentionally unstable composition), Christmas tree glass baubles with wires, glass buttons with metal shanks, a glass figure with a wire support, miners’ lamps, and a glass framed daguerreotype. These confirmed identifications might help conservators in investigating similar cases to shed more light on the formation conditions.  相似文献   

14.
《文物保护研究》2013,58(3):161-171
Abstract

Four iron meteorite fragments and 13 archaeological iron objects were exposed to a lowpressure hydrogen plasma for up to two weeks in a pilot apparatus. In the experiment the objects acted as cathodes in a 600–1600V d.c. electrical field. While the chlorine-containing β-FeOOH, akaganeite, was present in all objects before the test, no akaganeite and no chlorides were present afterwards. The objects, including one meteorite which had been exposed for more than 5000 years to seawater, were found to be stable after the glow discharge treatment. The major mineral after treatment was identified as magnetite, and the objects generally assumed an iron-grey surface colour. No sputtering and no reduction to free iron took place under the test conditions, operating at or below 120°C and at pressures of O·4–1mb hydrogen.  相似文献   

15.
Abstract

Paul Kantor’s methodology for availability analysis was applied to measure the degree of success or failure of the users of the General Collection of Punjab University Main Library in getting their needed documents. The availability success rate in this library was found to be 41·3%. Measurement of different performance factors indicated that segmentation of the library collection, absence of appropriate records for tracking down searches, inadequate user skills and insufficient and incompatible acquisitions were among the most significant factors impeding the availability of wanted items. These results were then compared with similar studies conducted in the academic libraries of the United States based on the same measurement methodology. Significant differences were noted in the overall measure of availability as well as for the factors related to library, users and acquisition. Implications of the study were reviewed to propose corrective measures.  相似文献   

16.
《文物保护研究》2013,58(2):147-153
Abstract

The compound 5-amino-2-mercapto-1,3,4-thiadiazole (AMT) is utilized in the conservation of archaeological and artistic bronze artifacts, for their protection and for the removal of corrosion products. Many authors have discussed the utility and efficacy of this, but few have studied the products resulting from the reaction of AMT with bronze or with the corrosion products of bronze; this leaves the restorer with many doubts concerning the acceptability of this method. This paper discusses the study of products obtained from the reaction of AMT with synthesized corrosion products of bronze (malachite, paratacamite and brochantite) and with the commercial bronze alloy TM 23 (Cu 72%, Pb 15%, Zn 8% and Sn 5%). It was found that the film obtained from the direct reaction of AMT with the bronze alloy can be AMT itself, or the metallic complex Cu(C2H2N3S2)2·H2O if AMT is applied in a solution of an oxidizing acid. These results are expected to be of value to conservation scientists and restorers/ conservators concerned with the use of AMT for the conservation of bronze artifacts.  相似文献   

17.

A NIGHT AT THE OPERA: MEDIA REPRESENTATIONS OF OPERA edited by Jeremy Tambling (1994—$28.00, paper, ISBN 0–86196–466–7, 310 pp.)

RADIO & AUDIENCE ATTITUDES by Andrea Millwood Hargrave (1994—$20.00, paper, ISBN 0–86196–481–0, ISSN 0960–3999, 104 pp.)

DOING BUSINESS WITH OFTEL: A GUIDE FOR SUPPLIERS AND LARGE USERS OF TELECOMMUNICATIONS SERVICES TO HOW THE REGULATORY PROCESS WORKS AND HOW TO MAKE THE BEST OF IT (no date but 1994—£10.00, paper, 60 pp.)

THE UK TELECOMMUNICATIONS INDUSTRY: MARKET INFORMATION (February 1995—£10.00, paper, 31 pp.)

A FRAMEWORK FOR EFFECTIVE COMPETITION: A CONSULTATIVE DOCUMENT ON THE FUTURE OF INTERCONNECTION AND RELATED ISSUES (December 1994—no price given, paper, 71 pp.)

ANNUAL REPORT 1994 (1995—£14.10, paper, 150 pp.)

IDENTIFICATION, GENDER AND GENRE IN FILM: THE CASE OF SHAME by Stephen Crofts (Melbourne: Australian Film Institute, 1993).

SITES OF DIFFERENCE: CINEMATIC REPRESENTATIONS OF ABORIGINALITY AND GENDER by Karen Jennings (Melbourne: Australian Film Institute, 1993)

THE GOLDEN AGE OF AUSTRALIAN RADIO DRAMA, 1923–1960 by Richard Lane (Melbourne: Melbourne University Press, 1994—A$49.95, ISBN 0–552–84556–8, 397 pp.)  相似文献   

18.
James Duncan Jr.'s American Radio: Spring '77 Report (Gilmore Advertising, 200 Michigan Bldg., Kalamazoo, Mich. 49006—$37.00 with a university rate of $28.00, paper)

F. Earle Barcus' Commercial Children's Television on Weekends and Weekday Afternoons (Action for Children's Television, 46 Austin Street, Newtonville, Mass. 02160— $25.00, paper)

Elmo I. Ellis' Opportunities in Broadcasting (Skokie, Ill.: National Textbook Co., 1977—$5.50/3.95)  相似文献   

19.
Objective:The authors used an assessment rubric to measure medical students'' improvement in question formulation skills following a brief evidence-based practice (EBP) training session conducted by a health sciences librarian.Method:In a quasi-experimental designed study, students were assessed using a rubric on their pre-instructional skills in formulating answerable EBP questions, based on a clinical scenario. Following their training, they were assessed using the same scenario and rubric. Student pre- and post-test scores were compared using a paired t-test.Results:Students demonstrated statistically significant improvement in their question formulation skills on their post-instructional assessments. The average score for students on the pre-test was 45.5 (SD 11.1) and the average score on the post-test was 65.6 (SD 5.4) with an average increase of 20.1 points on the 70-point scale, p<0.001.Conclusion:The brief instructional session aided by the rubric improved students'' performance in question formulation skills.  相似文献   

20.
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