Electrochemical fatigue crack treatment

Fatigue is responsible for at least 50% of all mechanical and 90% of all metallic failures. Fatigue cracks often start at stress concentrations, and without timely and appropriate remediation, tend to exhibit relatively fast propagation that leads to property damage and sometimes serious accidents. The objective of this research was to develop a new method of fatigue crack treatment in steel structures and estimate its efficiency and limitations. The method was based on placing fatigue cracks under compression by depositing nickel onto the surfaces of the cracks. The proposed method was applied to ASTM E399 compact-tension specimens machined from ASTM A36 steel. This study found that the method was able to arrest fatigue crack propagation. Fatigue crack arrest period varied from 2,000 to 30,000 cycles. The fatigue life of the specimens was extended for up to 55,000 cycles. In many cases the re-initiation life of fatigue cracks after treatment was similar to the crack initiation life obtained from the V-shaped starter notches. A power law relationship was developed that successfully correlates the fatigue crack arrest life and the stress intensity factor range applied for post-treatment load cycling. Fatigue crack packing with nickel resulted in significant reduction of stress concentration factors of the cracks. Spectroscopic analysis confirmed the presence of nickel in electrochemically treated fatigue cracks. The amount of nickel deposited was found to be non-uniform along the length of the cracks. This study found that an elastic finite element analysis (FEA) supported the notion of compressive stresses being developed at the crack tip and of a significant reduction in the stress concentration factor of the fatigue crack due to application of this treatment method. FEA has also supported the expectation that increasing the dosage of crack packing material would tend to result in a longer crack re-initiation period. The proposed method of electrochemical fatigue crack treatment was found to be beneficial in terms of improved corrosion resistance of treated specimens as long as the treatment was uniform and continuous. The average general corrosion rate of nickel-plated ASTM A36 steel specimens that were uncracked was 80% lower than that of the non-plated cases. The discontinuous deposition observed within cracks was expected to promote localized corrosion of the A36 base metal. Future work will examine the use of deposition candidates with less of a tendency toward dissimilar metal corrosion

The effects of an elevated pre-test heart rate on a cardiovascular test

This study investigated the effects of an elevated Pre-Test Heart Rate (PTHR) on the results of the Physical Working Capacity Maximum (PWC max) test and Steady State Heart Rates (SSHR) during the two workloads that are used to predict PWC max. Fifteen subjects (ages 18-33 yrs, height 169.38 +/- 9.77 cm, body mass 68.43 +/- 12.53 kg, percent body fat 22.27 +/- 7.40 %) participated in the study. PTHR was elevated using three methods prior to the administration of the PWC max test and the results compared to a criterion PWC max test that was completed after the subject was completely at rest. The three methods of elevating the PTHR were Exercise [EXER], Caffeine [CF], and Cold Pressor [CP]. The dependent measures were PWC max and the SSHRs of two workloads. The mean PWC max and standard deviation during the resting condition was 1368.73 +/- 587.7 kilogram meters (kgm) and the averages for the resting conditions were; EXER-1358.8 +/- 590.8 kgm, CF-1369.8 +/- 478.1 kgm, and CP-1308.2 +/- 486.1 kgm. (Abstract shortened by UMI.)

The Capital and Centers of Slovene Literature

Geografske analize ugotavljajo raznovrstnost glavnih mest, njihovo premičnost in nestalnost. Za zgodovino slovenske književnosti je značilno ločeno obstajanje glavnega mesta države in glavnega mesta nacionalne književnosti, imenovano literarna prestolnica. Ta se je v zgodovini oblikovala počasi, zaradi družbenopolitičnih razmer pa so poleg nje nastala v drugih delno slovenskih ali popolnoma tujih mestih tudi manjša središča slovenske književnosti. Med prestolnico nacionalne književnosti in njenimi središči obstajajo različna literarna razmerja, ki so posledica političnih procesov

Mobile Surveying of Cadastral Borders During the Adjudication of Parcel Boundaries

In this paper the mobile method of surveying cadastral border with mobile GIS applications is represented. Adjudication of parcel boundaries with presented method consists from next steps. In office geodetic expert transfers geodetic data into the field computer. In the field total station is placed to the most appropriate position. The total station is then connected to the field computer. By measuring cadastral border points that are identical to border points on cadastral map, the position of total station is obtained. By obtaining total stations position, the positional accuracy of total station is also obtained. With the positional accuracy of total station we can estimate the relative positional accuracy of cadastral map. When the position of total station is fixed, the transfer of cadastral border can be carried out. Main advantage of mobile method compared to classical method is that the field can be visited only once. In this paper the results of measurements on test field and on the actual cadastral case are presented. At the same time we carried out the same task with classical method of surveying cadastral borders during the adjudication of parcel boundaries, so that the comparison of two methods can be made

Prestolnica in središča slovenske književnosti

Geografske analize ugotavljajo raznovrstnost glavnih mest, njihovo premičnost in nestalnost. Za zgodovino slovenske književnosti je značilno ločeno obstajanje glavnega mesta države in glavnega mesta nacionalne književnosti, imenovano literarna prestolnica. Ta se je v zgodovini oblikovala počasi, zaradi družbenopolitičnih razmer pa so poleg nje nastala v drugih delno slovenskih ali popolnoma tujih mestih tudi manjša središča slovenske književnosti. Med prestolnico nacionalne književnosti in njenimi središči obstajajo različna literarna razmerja, ki so posledica političnih procesov

The aesthetic and cultural pursuits of patients with stroke

peer-reviewedTables to accompany this article on second fileGOAL: There has been an increasing interest in the arts in healthcare, with a suggestion that the arts and aesthetics can augment patient outcomes in stroke and other illnesses. Designing such programmes requires better knowledge of the artistic, aesthetic and cultural pursuits of people affected by stroke. The aim of this study was to obtain the insights of this group about the profile of arts and aesthetics activities in their lives as well as the influence of stroke on these aspects. MATERIALS AND METHODS: Patients attending a stroke service were administered questions adapted from the Irish Arts Council’s 2006 questionnaire on participation in aesthetics and cultural pursuits, Information was also collected on stroke type and present functional and cognitive status. Thirty-eight patients were interviewed. Of these, twenty were inpatients in hospital at the time of the interview and eighteen were interviewed in an outpatient setting. FINDINGS: Popular activities included mainstream cinema, listening to music, dancing, attending plays or musicals and being outdoors. Many patients ceased these activities after their stroke, mostly due to health issues and inaccessibility. The majority of patients valued the importance of the arts in the healthcare setting. CONCLUSION: This study gives a perspective for the first time on the aesthetic and cultural pursuits of stroke patients prior to their stroke. It portrays a wide variety of cultural and leisure activities, and the cessation of these post-stroke. It revealed the restrictions patients felt on gaining access to leisure pursuits both while in hospital and following discharge.Acceptedpeer-reviewe