Monitoring the development of microcracks in reinforced concrete caused by sustained loading and chloride induced corrosion

Chloride-induced corrosion of steel in reinforced concrete structures is one of the main problems affecting their durability and it has been studied for decades, but most of them have focused on concrete without cracking or not subjected to any structural load. In fact, concrete structures are subjected to various types of loads, which lead to cracking when the tensile stress in concrete exceeds its tensile strength. Cracking could increase transport properties of concrete and accelerate the ingress of harmful substances (Cl ^-, O₂, H₂ O, CO₂). This could initiate and accelerate different types of deterioration processes in concrete, including corrosion of steel reinforcement. The expansive products generated by the deterioration processes themselves can initiate cracking. The success of concrete patch repairs can also influence microcracking at the interface as well as the patch repair itself. Therefore, monitoring the development of microcracking in reinforced concrete members is extremely useful to assess the defects and deterioration in concrete structures. In this paper, concrete beams made using 4 different mixes were subjected to three levels of sustained lateral loading (0%, 50% and 100% of the load that can induce a crack with width of 0.1mmon the tension surface of beams - F _0.1) and weekly cycles of wetting (1 day)/drying (6 days) with chloride solution. The development of microcracking on the surface of concrete was monitored using the Autoclam Permeability System at every two weeks for 60 weeks. The ultrasonic pulse velocity of the concrete was also measured along the beam by using the indirect method during the test period. The results indicated that the Autoclam Permeability System was able to detect the development of microcracks caused by both sustained loading and chloride induced corrosion of steel in concrete. However, this was not the case with the ultrasonic method used in the work (indirect method applied along the beam); it was sensitive to microcracking caused by sustained loading but not due to corrosion. © 2014 Taylor & Francis Group.

An Integrated Toolkit for the Conservation of Stone-Built Heritage

Rapid in situ diagnosis of damage is a key issue in the preservation of stone-built cultural heritage. This is evident in the increasing number of congresses, workshops and publications dealing with this issue. With this increased activity has come, however, the realisation that for many culturally significant artefacts it is not possible either to remove samples for analysis or to affix surface markers for measurement. It is for this reason that there has been a growth of interest in non-destructive and minimally invasive techniques for characterising internal and external stone condition. With this interest has come the realisation that no single technique can adequately encompass the wide variety of parameters to be assessed or provide the range of information required to identify appropriate conservation. In this paper we describe a strategy to address these problems through the development of an integrated `tool kit' of measurement and analytical techniques aimed specifically at linking object-specific research to appropriate intervention. The strategy is based initially upon the acquisition of accurate three-dimensional models of stone-built heritage at different scales using a combination of millimetre accurate LiDAR and sub-millimetre accurate Object Scanning that can be exported into a GIS or directly into CAD. These are currently used to overlay information on stone characteristics obtained through a combination of Ground Penetrating Radar, Surface Permeametry, Colorimetry and X-ray Fluorescence, but the possibility exists for adding to this array of techniques as appropriate. In addition to the integrated three-dimensional data array provided by superimposition upon Digital Terrain Models, there is the capability of accurate re-measurement to show patterns of surface loss and changes in material condition over time. Thus it is possible to both record and base-line condition and to identify areas that require either preventive maintenance or more significant pre-emptive intervention. In pursuit of these goals the authors are developing, through a UK Government supported collaboration between University Researchers and Conservation Architects, commercially viable protocols for damage diagnosis, condition monitoring and eventually mechanisms for prioritizing repairs to stone-built heritage. The understanding is, however, that such strategies are not age-constrained and can ultimately be applied to structures of any age.

DNA mismatch repair and the DNA damage response to ionizing radiation:making sense of apparently conflicting data

The DNA mismatch repair (MMR) pathway detects and repairs DNA replication errors. While DNA MMR-proficiency is known to play a key role in the sensitivity to a number of DNA damaging agents, its role in the cytotoxicity of ionizing radiation (IR) is less well characterized. Available literature to date is conflicting regarding the influence of MMR status on radiosensitivity, and this has arisen as a subject of controversy in the field. The aim of this paper is to provide the first comprehensive overview of the experimental data linking MMR proteins and the DNA damage response to IR. A PubMed search was conducted using the key words "DNA mismatch repair" and "ionizing radiation". Relevant articles and their references were reviewed for their association between DNA MMR and IR. Recent data suggest that radiation dose and the type of DNA damage induced may dictate the involvement of the MMR system in the cellular response to IR. In particular, the literature supports a role for the MMR system in DNA damage recognition, cell cycle arrest, DNA repair and apoptosis. In this review we discuss our current understanding of the impact of MMR status on the cellular response to radiation in mammalian cells gained from past and present studies and attempt to provide an explanation for how MMR may determine the response to radiation.

Talking book repair group : history in Columbia, S.C. : fifty years of service, 1960 - 2010

This book gives the history of the South Carolina Chapter 61 of the Telephone Pioneers of America from 1960-2010. These volunteers repair talking book machines for the South Carolina State Library Talking Book Services.

Manutenção preditiva e pró-activa: filosofias alternativas ou complementares: estudo de caso

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Mecânica Ramo Manutenção e Produção

Evaluation of Bond Retainage in Portland Cement Concrete Overlays Using Infrared Thermography and Ground Penetrating Radar, HR-537, Final Report, 1989

When concrete deterioration begins to occur in highway pavement, repairs become necessary to assure the rider safety, extend its useful life and restore its riding qualities. One rehabilitation technique used to restore the pavement to acceptable highway standards is to apply a thin portland cement concrete (PCC) overlay to the existing pavement. First, any necessary repairs are made to the existing pavement, the surface is then prepared, and the PCC overlay is applied. Brice Petrides-Donohue, Inc. (Donohue) was retained by the Iowa Department of Transportation (IDOT) to evaluate the present condition with respect to debonding of the PCC overlay at fifteen sites on Interstate 80 and State Highway 141 throughout the State of Iowa. This was accomplished by conducting an infrared thermographic and ground penetrating radar survey of these sites which were selected by the Iowa Department of Transportation. The fifteen selected sites were all two lanes wide and one-tenth of a mile long, for a total of three lane miles or 190,080 square feet. The selected sites are as follows: On Interstate 80 Eastbound, from milepost 35.25 to 35.35, milepost 36.00 to 36.10, milepost 37.00 to 37.10, milepost 38.00 to 38.10 and milepost 39.00 to 39.10, on State Highway 141 from milepost 134.00 to 134.10, milepost 134.90 to milepost 135.00, milepost 135.90 to 136.00, milepost 137.00 to 137.10 and milepost 138.00 to 138.10, and on Interstate 80 Westbound from milepost 184.00 to 184.10, milepost 185.00 to 185.10, milepost 186.00 to 186.10, milepost 187.00 to 187.10, and from milepost 188.00 to 188.10.

A systematic review of the surgical treatment of large incisional hernia.

PURPOSE: Incisional hernia (IH) is one of the most frequent postoperative complications. Of all patients undergoing IH repair, a vast amount have a hernia which can be defined as a large incisional hernia (LIH). The aim of this study is to identify the preferred technique for LIH repair. METHODS: A systematic review of the literature was performed and studies describing patients with IH with a diameter of 10 cm or a surface of 100 cm2 or more were included. Recurrence hazards per year were calculated for all techniques using a generalized linear model. RESULTS: Fifty-five articles were included, containing 3,945 LIH repairs. Mesh reinforced techniques displayed better recurrence rates and hazards than techniques without mesh reinforcement. Of all the mesh techniques, sublay repair, sandwich technique with sublay mesh and aponeuroplasty with intraperitoneal mesh displayed the best results (recurrence rates of <3.6%, recurrence hazard <0.5% per year). Wound complications were frequent and most often seen after complex LIH repair. CONCLUSIONS: The use of mesh during LIH repair displayed the best recurrence rates and hazards. If possible mesh in sublay position should be used in cases of LIH repair.

Wakeman Burritt fonds, 1807-1814

Wakeman Burritt (1785-1847) was a merchant and ship owner who conducted his business in New York, New Orleans, LA, Charleston, SC, and the West Indies. Despite the difficulties that the Embargo Act of 1807 and the War of 1812 posed to trade and commerce, Burritt managed to run a successful business, dealing in commodities such as foodstuffs, cloth, cotton, and soap. He owned three ships, the Brig Cannon, Brig Eunice and Brig Sampson. In 1809, he married Grace Burr (1787-1874). Together they had at least one child, Francis Burritt (1811-1861).

Wakeman Burritt Fonds

Fonds consists of correspondence between Wakeman Burritt and his business associates, as well as receipts and documents concerning the shipping vessels Brig Cannon, Brig Eunice, Brig Sampson, and several other vessels. Reference is made in some documents to the effects of politics on commerce, most notably the Embargo Act of 1807 and the War of 1812. The correspondence consists of 53 letters, 40 of the letters being addressed to Wakeman Burritt, with the remaining 13 letters being retained copies of letters written by Burritt to Samuel Cannon. There are also 17 letters written to Burritt by LeGrand Cannon of Norwalk, CT. The remaining letters to Burritt consist of two letters from his wife Grace Burritt, and other business associates, including Thomas Andrews, Stephen Arnold, Ezra Burr, Talcott Burr, Talmon Burr, Wm. M. Betty & Co., Samuel Cannon, Edward Jessup, Hugh Knox, Jonathan Meigs, Samuel Morehouse, Stephen Morehouse, W & B St. John, Oliver Sherman, Anthony Stow, and Ogden Richards Weldon. The shipping vessel material includes 52 documents concerning Brig Eunice, 27 documents for Brig Sampson, 14 documents for Brig Cannon, and 18 miscellaneous documents for vessels such as the Schooners Maria, Hope, Nassau, and Henry, Sloops Fox and Sally, and the Brig Diana and Emeline. The documents include receipts for piloting into port, for wharfage, and for supplies and repairs, as well as lists of disbursements, freight lists, and payments made to men working on the ships.

Receipt to S.D. Woodruff from P. Cougle

Receipt to S.D. Woodruff from P. Cougle for repairs to clothing, Nov. 3, 1845.

Receipt to S.D. Woodruff from P. Cougle

Receipt to S.D. Woodruff from P. Cougle for repairs to clothing, May 16, 1846.

Receipt to Mr. S.D. Woodruff from Peter Cougle

Receipt to Mr. S.D. Woodruff from Peter Cougle for repairs to clothing, Nov. 12, 1846.

Receipt to Mr. S.D. Woodruff from P. Cougle

Receipt to Mr. S.D. Woodruff from P. Cougle for repairs to clothing, July 29, 1848.

Receipt to S.D. Woodruff from T. Healey

Receipt to S.D. Woodruff from T. Healey of St. Catharines, dealers in Boots, Shoes, Rubbers and Gaiters regarding shoes and shoe repairs, Jan. 1, 1876.

Letter - Holmes' Burglar Alarm, Telegraph Company to S.D. Woodruff

Letter to S.D. Woodruff from the Holmes’ Burglar Alarm, Telegraph Company of New York stating that they will send a Mr. Whittaker over to make repairs or changes. There is a partial envelope included with this letter, Feb. 8, 1881.