Measurement of wide frequency range structural microvibrations with a pocket digital camera and sub-pixel techniques

Analysis of vibrations and displacements is a hot topic in structural engineering. Although there is a wide variety of methods for vibration analysis, direct measurement of displacements in the mid and high frequency range is not well solved and accurate devices tend to be very expensive. Low-cost systems can be achieved by applying adequate image processing algorithms. In this paper, we propose the use of a commercial pocket digital camera, which is able to register more than 420 frames per second (fps) at low resolution, for accurate measuring of small vibrations and displacements. The method is based on tracking elliptical targets with sub-pixel accuracy. Our proposal is demonstrated at a 10 m distance with a spatial resolution of 0.15 mm. A practical application over a simple structure is given, and the main parameters of an attenuated movement of a steel column after an impulsive impact are determined with a spatial accuracy of 4 µm.

Daily pocket journal of John and Hannah Winthrop, 1766-1779

Small printed daily pocket journal repurposed by both John and Hannah between 1766 and 1779 to record household accounts including livestock pasturing, income received, and payments to servants, merchants, and tradesmen for food, livestock, clothing, linen, etc. Many of the pages are unused. The January-April pages contain account records from 1766-1779, one page in June has a few accounting notes from September 1779, the rest of June-November is empty, and three books are listed on a November page. The last three calendar pages contain lists of books in Hannah's handwriting dated 1773 and August 1768.

Fleets pocket almanack for the year of our Lord, 1790

Annotated and interleaved almanac in marble-paper covers with minimal annotations to the calendar pages, generally "S" and "J." The interleaved pages contain sporadic handwritten entries noting deaths in the community, and ministers whose sermons Pearson attended.

Fleets’ pocket almanack for the year of our Lord, 1793

Annotated and interleaved almanac in marble-paper covers with minimal annotations to the calendar pages, generally "JB" and "SB." The interleaved pages contain sporadic handwritten entries including notes about Pearson's recovery from a broken leg, farming and a diagram of planted apple trees, Harvard staff hirings, deaths in the community, ministers whose sermons he attended, and Bible citations.

A Pocket almanack for the year of our Lord, 1796

Annotated and interleaved almanac in marble-paper covers with minimal annotations to the calendar pages, generally "J" and "S." The interleaved pages contain sporadic handwritten entries including brief notes about deaths in the community, ministers whose sermons Pearson attended, Corporation meetings, and student examinations. There are entries noting the deaths of Harvard undergraduates Isaac Wellington (who drowned) and Francis Brigham (who died of a fever). The almanac is the version printed and sold in Boston by T. & J. Fleet.

Fleets’ register, and pocket almanack for the year of our Lord, 1799

Annotated and interleaved almanac in marble-paper covers with minimal annotations to the calendar pages, generally "Jun" and "Sen." The interleaved pages contain sporadic handwritten entries including brief notes about ministers whose sermons Pearson attended, Bible citations, and student examinations.

Relationships of pocket gophers of the genus Geomys from the Central and Northern Great Plains / by Lawrence R. Heaney and Robert M. Timm.

no.74 (1983)

C. Daily pocket journal of John and Hannah Winthrop, 1766-1779

Small printed daily pocket journal repurposed by both John and Hannah between 1766 and 1779 to record household accounts including livestock pasturing, income received, and payments to servants, merchants, and tradesmen for food, livestock, clothing, linen, etc. Many of the pages are unused. The January-April pages contain account records from 1766-1779, one page in June has a few accounting notes from September 1779, the rest of June-November is empty, and three books are listed on a November page. The last three calendar pages contain lists of books in Hannah's handwriting dated 1773 and August 1768.

An account of my quarter bills, charges &c from July 11th 1743 to July 13th 1748 at Harvard College

Handwritten account book kept while Storer was a student at Harvard College. The well-organized volume is arranged by expense type and then date and was updated periodically, usually quarterly. The information offers a glimpse at the expenses of a Harvard student and provides information about the larger community that supported student life. The precise entries indicate the lifelong habits of Storer as a careful and methodical financial manager that would prove so valuable when he served as Harvard's treasurer more than thirty years later. Storer documents accounts with the steward, butler, sweeper, glazier, barber, and lists these individuals by name. The volume also includes notes on expenses for boarding, transportation, wood, and pocket expenses. While most entries do not list specific purchases, Storer provides details on the cost of a Harvard Commencement in 1747 (including the cost of a diploma, money to the President, hiring a house, a boat, a woman, and "2 Negroes"), and a specific accounting of the different food purchased for the event; Storer also lists expenses for an 1748 "supper for the graduates."