|About this Technical Note|
|This technical note was
written to fill an information gap in the shipboard
physical properties laboratory and to enhance effective
use, management, and maintenance of the physical
properties instrumentation and data. The timing of this
first release of the note is closely linked to the
completion of the new ODP database development (Janus
project), which allowed us to redefine data quality
standards and data acquisition and archiving
The objectives of the note are to:
In the "Introduction" chapter, the physical properties laboratory is introduced in the context of laboratory stations which are closely linked to the "core flow" (i.e., the processing of a core from the moment it arrives on deck to the moment it is archived in the ships refrigerator). General sampling procedures and strategies are also addressed in this section. Additional topics are brief overviews of the new data management and archiving system, measurement standards, and the use of physical units.
Each of the following chapters is dedicated to a particular physical property routinely measured on the ship at one or more laboratory stations. An introduction to the physical background is followed by considerations of environmental effects and the basic use of the data. Then, the one or more measurement systems used to measure the property are described, including equipment used, calibration and measurement principles and procedures, and performance. This particular organization of the bulk of information was chosen because continuing improvements in the laboratory will increasingly result in certain properties being measured at multiple stations. Redundant measurement systems provide the flexibility to better adapt to varying core material and to upgrade some systems without abandonning the old way of measurement.
Users need access to data specifications to understand how raw measurements are translated into the numbers provided by ODP. Therefore, each section covering a measurement system also presents the exact data model implemented in the new ODP database, queries available to the user for data retrieval, and algorithms used in the queries.
Each section covering a measurement system presents calibration and measurement procedures in a generic way, focusing on issues essential for maintaining the best data quality possible. Step-by-step tutorials for operating the data acquisition programs and instruments are not included here. The programs controlling the instrumentation evolve rapidly as new computer hardware and software become available, and user interfaces are improved almost continuously. In most cases, these upgrades do not affect the principles and data models presented here, but slightly modify the hands-on procedures. On-line help for running the programs exist at an increasing number of laboratory stations.
Much of the information compiled here summarizes the last four years of intensified hardware, software, and procedure development. It focuses on questions and issues that have come up repeatedly on many legs in regard to measurement and calibration principles, data quality, user-friendliness of programs, data access and data structure, environmental corrections, etc. However, this note is a snapshot of a moving target: the laboratory will continue to evolve and the level of information should be enhanced on a continuing basis. Both improvements in the laboratory and enhancements to this note can benefit from user input. In fact, one of the objectives of the note is to facilitate input by users who are encouraged to submit comments and suggestions at any time to the author or to other ODP personnel.