Cellulosic materials Sample Clauses

Cellulosic materials. The effect of exposure of acidic volatiles on paper degradation was explored in detail, by the University of Natural Resources and Life Sciences, Vienna, to finally generate practically valid guidelines for conservation of cultural heritage objects consisting of cellulose (Figure 3). In order to simulate cellulose degradation by acids, the conventional ageing in closed vessels had to be modified and a better understanding on how to perform an accelerated aging for paper has been established. Ten different species of papers were aged naturally (room temperature) and under accelerated (elevated temperature) conditions in presence of different concentrations of acetic and formic acid. Evaluation of paper degradation induced was carried out by measuring the molar mass distribution and keto/aldehyde contents using size-exclusion chromatography with MALLS/RI and selective fluorescence labeling – a special technique which is able to report even small changes to the cellulose molecule and hence able to judge the stability of the most important polymer in paper - cellulose. This approach allows to measure the velocity (speed) of cellulose degradation, i.e. how fast a cellulose chain is split under the conditions applied. The longer the cellulose chains on the molecular level are the stronger the overall polymer is. Chain length can hence be directly correlated to the stability of the paper or textile. The faster the cellulose molecules (polymer chains) are cleaved the faster the material deteriorates. Hence, the speed of degradation is an useful measure to analyze the stability in the presence of e.g. organic acids. Figure 3: Schematic presentation of the effect of acetic acid on paper. The rate of cellulose chain scission, as mentioned above a sensitive measure to analyze cellulose stability, could be determined as a function of acidic vapour concentration at different aging periods and different temperatures. The rate of degradation obtained is directly proportional to the concentration of acetic acid vapour – a parameter analyzed by the MEMORI dosimeter. Acetic and formic acid are able to accelerate cellulose degradation even at low concentration (>1.5 mg/m3) levels of acid vapour. The results from the different exposure types, tested in order to get reliable results, imply that hydrolysis of cellulose in presence of acidic vapour is not only dependent on the concentration of acid in the vapour, but also on the amount of acid in the paper after reaching an equil...
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Related to Cellulosic materials

  • Recycled Materials Xxxxxxx County encourages the use of products made of recycled materials and shall give preference in purchasing to products made of recycled materials if the products meet applicable specifications as to quantity and quality. Xxxxxxx County will be the sole judge in determining product preference application.

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  • FABRICATION Making up data or results and recording or reporting them.

  • Manufacturing (a) The Supplier shall without limitation be responsible, at no additional cost to the Purchaser, for: sourcing and procuring all raw materials for the Products; obtaining all necessary approvals, permits and licenses for the manufacturing of the Products; providing sufficient qualified staff and workers to perform the obligations under this Purchase Agreement; implementing and maintaining effective inventory and production control procedures with respect to the Products; and handling other matters as reasonably requested by the Purchaser from time to time.

  • Biological Samples If so specified in the Protocol, Institution and Principal Investigator may collect and provide to Sponsor or its designee Biological Samples (“Biological Samples”). 12.2.

  • Customer Materials 12.1 The Supplier including any of its employees, agents, consultants, contractors and any third party shall:

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  • Recyclable Materials “Recyclable Materials” means Solid Waste consisting of any material 371 which retains useful properties and can be reclaimed after the production or consumption process.

  • Products Products available under this Contract are limited to Software, including Software as a Service, products and related products as specified in Appendix C, Pricing Index. Vendor may incorporate changes to their product offering; however, any changes must be within the scope of products awarded based on the posting described in Section 1.B above. Vendor may not add a manufacturer’s product line which was not included in the Vendor’s response to the solicitation described in Section 1.B above.

  • Consumables During the design phase, Purchaser may participate in the selection of suppliers of consumables of the Supplier. In such case, the choice regarding the final selection of the said suppliers shall be mutually agreed between the Parties. Two suppliers shall be identified and selected for each type of consumables.

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