Unused Tubes Research Articles

Evaluation of Internal Pressure Creep Rupture Life of Boiler Tube Using Miniature Tensile Creep Test

Abstract Many studies have been made for evaluating the creep rupture life of a boiler tube. The working stress of a tube under internal pressure is calculated mostly by the mean-diameter formula adopted in design for pressurized components. However, this stress is not always representative of a complex stress state under internal pressure. So, focusing on the representative stress, internal pressure and uniaxial creep tests were conducted using unused and 90,000-h used boiler tubes of Type 321 stainless steel in this study. A miniature specimen (1.5 mm in width, 1.5 mm in thickness, and 25 mm in length) for the uniaxial test was taken from the middle of the tube wall in the direction of the maximum principal stress. As a result, the mean-diameter formula did not present good agreement between internal pressure and uniaxial creep rupture lives. Hence, as an alternative stress, von Mises equivalent stress, which presents good correlation between uniaxial and multiaxial creep rupture properties, was chosen. The equivalent stress, σ*, at the middle of a tube wall was calculated using Rimrott’s solution to internal pressure creep of thick-walled tubes considering large deformation. Because σ* increases with creep strain under internal pressure, σ* at εθo = εθof / 2 (where, εθo and εθ0f are tangential and tangential rupture strains on the outer diameter, respectively) was employed as the representative stress. Consequently, this stress resulted in good agreement between both creep rupture lives for the unused tube. However, the internal pressure creep rupture life of the used tube was inconsistent with the uniaxial life, which was attributed to the existence of an outside layer due to exposure to combustion gas. Using a reduction rate of the rupture ductility of the layer, the internal pressure creep rupture life of the used tube was evaluated well with the unused tube.

The Effects of Long-Term Operation and High Temperature on Material Properties of Austenitic Stainless Steel Type 321H

Changes in mechanical properties of material as a result of service in different conditions can be provided by mechanical testing to assist the estimation of current internal situation of these materials, or the degree of deterioration may exist in furnaces serviced at high temperature and exceed their design life. Because of the rarity works on austenitic stainless steel material type AISI 321H, in this work, ultimate tensile strength, yield strength, elongation, hardness, and absorbed energy by impact are evaluated based on experimental data obtained from mechanical testing. Samples of tubes are extracted from furnace belong to hydrotreaterunit, also samples from un-used tube material are used to make comparisons between these properties. Tensile properties of stainless steel (AISI 321H) were decreased as temperature increases; the trend of properties decreasing for the samples of un-used tube material is the same for the ex-used material. The trend of stress-strain curve will not change due to elevated temperature exposure for long time of service, except the yield strength will be higher in this diagram. The yield strength increased under these conditions, but the ability of material which is elongated will decrease. Hardness and absorbed energy increased by 11.28 and 14% respectively when the material is aged for long time under effect of high temperature accompanied with creep effect.
 Keywords: Hardness, Impact, Mechanical Properties, Stainless Steel 321H, Mechanical Properties, Tensile Strength, Tube Furnace.

Deposition of mannose-binding lectin and ficolins and activation of the lectin pathway of complement on the surface of polyurethane tubing used for cardiopulmonary bypass.

The artificial surface used for cardiopulmonary bypass (CPB) is a crucial factor activating the complement system and thus contributing to the generation of a systemic inflammatory response. The activation of classical and alternative pathways on this artificial surface is well known. In contrast, lectin pathway (LP) activation has not been fully investigated, although noted during CPB in several studies. Moreover, we have recently proved the contribution of the LP to the generation of the systemic inflammatory response syndrome after pediatric cardiac surgery. The aim of this study was to assess LP-mediated complement activation on the surface of polyurethane CPB circuit tubing (noncoated Chalice ® ), used for CPB procedures in children with congenital heart disease. We found deposition of mannose-binding lectin, ficolin-1, -2, and -3 on the surface of unused tubing and on tubing used for CPB from a small minority of patients. Furthermore, we observed deposition of complement C4 activation products on tubing used for CPB and previously unused tubing after incubation with normal serum. The latter finding indicates LP activation in vitro on the polyurethane surface. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1202-1208, 2018.

A Cluster of Surgical Site Infections following Breast Augmentation and Face Lift Surgery.

Sir: Surgical site infections (SSIs) have been reported as the most common causes of readmission after plastic surgery.1 In July 2013, the U.S. Centers for Disease Control and Prevention and Missouri State Health Department investigated reports of 5 SSI cases following breast augmentation surgeries. The case-patients’ surgeries were performed at a single outpatient plastic surgery clinic (clinic A) during May–June 2013. An epidemiologic investigation was performed with the cooperation and support of the clinic and the surgeon who detected the cluster among his patients. We defined a case as a patient who had surgery at clinic A between May and July 2013, with subsequent signs or symptoms of SSI, which include any of the following: pain, redness, swelling, discharge at the wound, or unhealed wound. We identified 8 case-patient: 6 following breast augmentation using a solid implant and 2 following face lift surgery. The first case-patient had breast surgery in May 2013 and developed symptoms after 4–6 weeks. This case had Mycobacterium identified by polymerase chain reaction from a breast tissue sample; the remaining case-patients had negative microbiological testing. All case-patients experienced mild pain and tenderness, some discharge and delayed wound healing. All of the case-patients’ procedures were performed by the same surgeon. Cases seemed to occur after the surgeon switched, in April 2013, to a different lubricating gel product to assist with implant insertions. Review of clinic records showed that the clinic’s overall SSI rate was 0.2% (13 cases) during 12 months prior to this cluster. We reviewed the steps of a breast augmentation surgery with the surgeon and observed infection control practices at clinic A. Instead of using disposable implants or Food and Drug Administration (FDA)-approved resterilizable implants as sizers, actual single-use implants were reused by subjecting them to enzymatic cleansing and steam sterilization. Testing of one implant that had been reprocessed in this manner identified alpha Streptococcus and coagulase-negative Staphylococcus species. The aforementioned lubricating gel was used around the incision sites and on the sizers and implants. The gel was labeled bacteriostatic and as being intended to lubricate body orifices and facilitate entry of diagnostic and therapeutic devices. However, testing of only one available open unused tube of gel at U.S. Centers for Disease Control and Prevention did not identify mycobacteria or other pathogens. In response to the cluster, the surgeon temporarily discontinued breast augmentation surgery. When surgery was restarted, FDA-approved resterilizable implants were used as sizers, and the surgeon reverted to the previous brand of lubricating gel, which had similar labeling as the gel mentioned above. No new cases have been reported to date. Although a definitive mode of transmission was not determined, our investigation identified possible sources of infections and raised some important points for plastic surgeons to consider. Growth of bacteria from the tested sizer indicated one potential source of infection; reuse of single-use implants as sizers may be unsafe as this is neither approved by FDA nor recommended by the manufacturer. In addition, the use of lubricating gel directly on sterile tissues during operations represented another potential source of infection. These gel products are not indicated for that purpose; we are not aware of any lubricating gel products that are labeled for use on sterile surgical fields. The labeling of these gels may require clarification and greater specificity in this regard. In summary, we recommend that surgeons adhere carefully to manufacturer instructions, use only FDA-approved reusable or single-use sizers, and not use lubricating gel products on sterile tissues for placement of these devices.

Damage assessment of boiler tubes subjected to erosion and corrosion failures by non-invasive technique

Incompatible permanent strains in any engineering component are caused by the formation of residual stresses due to mechanical loading or thermal effect. They get generated or modified at every stage of the service life of the component. The stresses tend to increase due to the type of damage occurring in any engineering component such as fatigue, corrosion, erosion, or a synergistic effect under the influence of environmental conditions. The present investigation highlights about the residual stresses in a typical boiler tube component and the same is characterized by nondestructive methods viz., Magnetic Barkhausen Noise and X-ray Diffraction techniques to identify the type of damage such as corrosion and erosion have been discussed. The correlation of the stress data with respect to the hardness and microstructure of the in-service boiler tubes in comparison with an unused tube has been attempted. The result reveals that there is a considerable variation in the magnitude of the stress level as well as the hardness value in the damaged region compared to the unaffected location. Furthermore, it is seen that the microstructural features support the data. The damage assessment methodology thus serves as a tool to quantify the type and extent of damage of in-service tubes and forms a part of the quality assurance practice.

Endotracheal tube intraluminal diameter narrowing after mechanical ventilation: use of acoustic reflectometry

To quantify the incidence and degree of endotracheal tube intraluminal obstruction after mechanical ventilation and its relation to time of intubation. Prospective observational study. A 14-bed medical-surgical intensive care unit at a university-affiliated teaching hospital. Ninety-four endotracheal tubes used in 80 patients requiring mechanical ventilation for more than 12 h. Acoustic reflectometry was performed in every endotracheal tube after patient extubation to measure its volume reduction. The intraluminal volumes of used endotracheal tubes in mechanically ventilated patients were significantly lower than those of unused tubes of the same size (5.52+/-0.92 ml(3) versus 6.54+/-0.79 ml(3), p<0.05). The mean difference in endotracheal tube segment volumes was 15.2% (range 0-66%). Volume reduction was above 10% in 60.8% of the tubes. In 22% of endotracheal tubes the remaining inner diameter was less than 7 mm. Reduction below this figure was less frequent (9.3%) in tubes 8 mm or more (p<0.05). The percentage of endotracheal tube volume reduction was not associated with the duration of intubation (r=-0.09, p= n.s.) Peak pressure measured before extubation did not predict obstruction (r=0.11, p= n.s.). Inadvertent endotracheal tube obstruction was common in patients requiring mechanical ventilation and may be significant as early as at 24 h. Moderate obstruction in endotracheal tube lumens should be suspected in cases of difficulties in weaning, even in patients who were ventilated for less than 1 day.

Charles Henry Collins Baker: Biographical and Bibliographical Note

C harles Henry Collins Baker (1880-1959), art historian, painter, and art critic, was born on 24 January 1880 at Bay Hill in Ilminster, Somerset, the son of John Collins Baker, a solicitor, and Fanny Henrietta Remmett. In 1903 he married Muriel Isabella (1874/5-1956); they had one daughter, Phyllis. Collins Baker was educated at Berkhampstead and studied art at the Royal Academy Schools, London. He began his career as a landscape painter and exhibited in 1907 at the Royal Academy and from 1909 to 1916 at the New England Art Club, also serving as the club's honorary secretary from 1921 to 1925. His art works, signed C.H.C.B., can be found in the Manchester City Art Gallery, Leeds City Art Gallery, and Huddersfield Art Gallery. From 1932 to 1949 he was a senior research associate in British art at the Huntington. In 1911 he began his work as an art critic, contributing articles to The Outlook and Saturday Review; he also accepted an appointment as private assistant to Sir Charles Holroyd (1861-1917), director of the National Gallery, London, and was promoted to keeper in 1914. Early in his career at the National Gallery he wrote his most important book, Lely and the Stuart Portrait Painters (1912), a pioneering work in the study of British art. He continued as keeper under Holroyd's successor at the National Gallery, Charles John Holmes (1868-1936), who served as director from 1916 to 1928. Holmes later wrote, Baker's unselfish energy relieved me of more than half my labours, his dry, affectionate humour lightened all the rest, instinctive friendship being cemented by our common danger,' the bombardment of London during World War I. Holmes and Collins Baker supervised the movement of nine hundred of the gallery's best pictures to the unused Tube station in the Strand to keep them safe from air raids.2 Holmes

An in vitro study of silicone migration from intravenous fluid tubing.

Migration of particulate matter from plastic tubing and solid plastic implants has been documented in a number of studies, including some with the use of cardiac bypass, haemodialysis, and pump-assisted intravenous infusions. In order to ascertain whether silicone embolisation occurs when children have an Ivac 560 pump-assisted IV infusion, we passed 180 ml of pumped fluid through a microfilter and compared the scanning electron micrographs of those filters with unused filters and with others through which a similar volume had been passed without using the pump. The particles on the filters were analysed for their elemental content using energy-dispersive X-ray analysis. In addition, the appearance of the silicone tubing used in the pump over 3 and 72 h was assessed and compared to that of flow-only and unused tubing. More particles were found on the microfilter when fluid had been delivered via the pump than on those through which non-pumped fluid had passed or that were unused. Elemental silicon-containing particles were only found on the filter when a pump had been attached to the IV line. The flow-only and unused tubing were found to have adherent particles on the inner surface that were not seen once the tubing had been used for 3 h in the Ivac 560 pump. Also, after 72 h use, the silicone tubing had a deformed inner layer. The clinical significance of these findings is yet to be determined, but it does appear that silicone embolisation occurs during pump-assisted infusions in children.

Determination of the spatial distribution of trace elements in stainless steel by imaging microprobe secondary ion mass spectrometry

Imaging microprobe secondary ion mass spectrometry (SIMS) using a liquid metal ion source (LMIS) has been used to determine the spatial distribution of metal ions in stainless steel. This scanning ion microprobe is used to achieve high resolution chemical maps of the surface of a sample. For conductive samples such as stainless steel, the practical spatial resolution approaches 0.2 μm and the sensitivity varies with the ion of interest. We have obtained important information relating to the distribution of surface contaminants, segregation, and corrosion phenomena of the elements in these alloys. In this report we hope to demonstrate the usefulness of this important new technique by describing its capabilities and by reviewing data obtained from two separate studies involving stainless steel. Significant findings obtained in these mapping experiments were: • . Stainless steel 316 tubing, which had been found previously to be catalytically active, showed remarkable differences between the used and unused samples. Sodium, potassium, and hydrocarbons were found to exist in agglomerations (islands) in the unused tubing, but were very well distributed in the used tubing. • . A used stainless steel impeller was found to be inhomogeneous with respect to iron and chromium. The surface was entirely covered by chlorine, which is believed to be responsible for the corrosion. Water and elevated levels of chloride ion were found inside numerous scratches or fissures covering the surface. The unused stainless steel showed no signs of streaks or segregated metal regions, and was free from fissures.

End-Tidal CO2 Measurement in the Detection of Esophageal Intubation During Cardiac Arrest

Measurement of end-tidal carbon dioxide (ETco 2 ) has been used to detect accidental esophageal tube placement in noncardiac arrest situations. The purpose of our study was to determine whether ETco 2 measurement could distinguish tracheal from esophageal tube placement during closed-chest massage (CCM). Twelve large dogs were anesthetized, and endotracheal tubes were placed in both the trachea and the esophagus. Placement was verified by fiberoptic endoscopy. Ventricular fibrillation was induced by a 60-Hz discharge through a right ventricular pacemaker. After four minutes of cardiac arrest, CCM was initiated and continued for 20 minutes. The dogs were divided into two groups: Group A was ventilated through the tracheal tube, and group B was ventilated through the esophageal tube. Unused tubes were removed. ETco 2 was recorded continuously beginning two minutes before arrest until the end of the experiment. There were no significant between-group differences in mean arterial pressure, weight, blood loss, IV fluid volume administered, or prearrest arterial blood gases. ETco 2 differed significantly between the two groups throughout CCM ( P = .001). In group A, ETco 2 ranged from 13 to 34 mm Hg (median, 20 mm Hg). In group B, ETco 2 ranged from 2 to 11 mm Hg (median, 3 mm Hg). In this experimental model, measurement of ETco 2 reliably distinguished esophageal from tracheal intubation during cardiac arrest and CCM. If confirmed in human beings, this may prove to be a quick, reliable method of detecting esophageal intubation during cardiac arrest.

End-tidal CO 2 measurement in the detection of esophageal intubation during cardiac arrest

Measurement of end-tidal carbon dioxide (ETCO2) has been used to detect accidental esophageal tube placement in noncardiac arrest situations. The purpose of our study was to determine whether ETCO2 measurement could distinguish tracheal from esophageal tube placement during closed-chest massage (CCM). Twelve large dogs were anesthetized, and endotracheal tubes were placed in both the trachea and the esophagus. Placement was verified by fiberoptic endoscopy. Ventricular fibrillation was induced by a 60-Hz discharge through a right ventricular pacemaker. After four minutes of cardiac arrest, CCM was initiated and continued for 20 minutes. The dogs were divided into two groups: Group A was ventilated through the tracheal tube, and group B was ventilated through the esophageal tube. Unused tubes were removed. ETCO2 was recorded continuously beginning two minutes before arrest until the end of the experiment. There were no significant between-group differences in mean arterial pressure, weight, blood loss, IV fluid volume administered, or prearrest arterial blood gases. ETCO2 differed significantly between the two groups throughout CCM (P = .001). In group A, ETCO2 ranged from 13 to 34 mm Hg (median, 20 mm Hg). In group B, ETCO2 ranged from 2 to 11 mm Hg (median, 3 mm Hg). In this experimental model, measurement of ETCO2 reliably distinguished esophageal from tracheal intubation during cardiac arrest and CCM. If confirmed in human beings, this may prove to be a quick, reliable method of detecting esophageal intubation during cardiac arrest.

Scanning electron microscopy studies on surfaces from electrothermal atomic absorption spectrometry-V. Glassy carbon tubes

Morphological studies on the surfaces of glassy carbon tubes by scanning electron microscopy are presented for unused tubes and for those from various endurance experiments in electrothermal atomic absorption spectrometry. Surfaces of unused tubes may differ greatly depending on manufacturer and manufacturing date. Corrosion on the outer tube surface was largely independent of the matrix and exhibited a tooth-shaped morphology. Corrosive attack on the inner surface was found to depend much more on the matrix and its oxidizing power. For matrices which tended to recondense at the cooler tube ends erosion was more pronounced in these areas than in the hot center. The attack of high iron and lanthanum concentrations was found to be more severe than that of perchloric acid. Removal of the protective skin, which is responsible for the low reactivity of glassy carbon with oxygen, followed by penetration into and enlargement of the micropores was a frequently observed mechanism of attack. Clear evidence was found for catalytic graphitization, i.e. crystallization of the largely amorphous glassy carbon, in the presence of high masses of iron and lanthanum. The crystalline graphite gave rise to the formation of intercalation compounds which eventually resulted in preferential oxidation and vaporization of this carbon type.

Electron microscopic evaluation of bacterial adherence to polyvinyl chloride endotracheal tubes used in neonates.

Studies in adults suggest a possible association between pulmonary nosocomial infection and bacterial adherence to endotracheal tubes (ETT). Some strains of coagulase-negative Staphylococcus produce a mucoid extracellular material known as slime or glycocalyx that helps bacteria adhere to the surface of biomaterials. We examined by scanning and transmission electron microscope the surface of 29 polyvinyl ETT removed from neonatal patients, and ten unused ETT. Multiple surface irregularities were found in the unused tubes. These irregularities were most prominent in the tip and around the side hole. Amorphous material containing slime-producing bacteria was found on 29 ETT removed from patients. Tubes in place for longer times had greater areas of surface covered; the amorphous material was more concentrated in the areas where surface irregularities were most prominent. No clinical correlation with pulmonary nosocomial infection was established.

Corrosion studies with pixe

To investigate the possible causes of corrosion of some of the tooth paste tubes of a major international cosmetic product manufacturer, the elemental compositions of corroded and clean unused tubes were compared, using PIXE. It was observed that some of the corroded tubes contained much higher amounts of Ti, Fe, Ga and Zn than the clean tubes, while the concentrations of Cr and Ni showed no significant difference between the two types of tubes. Only certain regions of one of the tubes were found to contain higher concentrations of Cu. Those regions were badly corroded and had the highest concentrations of Ti, Fe, Ga and Zn, too. It is suggested that the presence of higher amounts of Ti, Fe, Ga and Zn, and especially of Cu, in the aluminium sheets used to manufacture the tooth paste tubes, may be one of the reasons for the corrosion of some of the tooth paste tubes.

Loss of Phthalic Acid Ester from Polyvinyl Chloride Tubing into Various Fluids

Migration of phthalic acid esters (PAE) from polyvinyl chloride (Tygon) tubing, approved for use with processed milk and milk products, was measured under conditions simulating normal daily use. Squares of tubing were soaking in water at 18, 44, and 72 C; milk at 38 C; aqueous solutions of two chlorinated alkaline cleaners at 62 C and use dilution; and three sanitizers at 24 C and use dilution. Each soaking solution was extracted using the AOAC Method for organochlorine pesticides and analyzed quantitatively for PAEs by gas liquid chromatography. Water at 72 C extracted greater amounts of PAEs than water at 18 or 44 C. Milk extracted the least amounts of PAEs; values were usually less than 1 ppb per day. Little difference was seen between the two chlorinated alkaline cleaners. Sanitizers, in general, extracted the greatest quantities of PAEs, averaging about 3 ppb per day. Leaching patterns of the individual sanitizers varied. Deformation tests were made on the used squares of tubing with a penetrometer. No change was found compared to samples of unused tubing (control), indicating longer use and greater PAE loss is necessary before tubing flexibility is affected.

A comprehensive safety shutter and collimator coupling for the Philips X-ray tube shield PW 1016

A set of safety shutters and collimator couplings for the Philips X-ray tube shield PW 1016 have been designed and made for use with (i) the Enraf-Nonius Weissenberg camera, (ii) the Charles Supper precession camera, (iii) the Philips Debye-Scherrer powder camera, (iv) the Nonius Guinier powder camera and (v) unused tube windows. The shutter couplings provide (i) a scatter shield around the filter disk, (ii) a scatter shield around the collimator face, (iii) a gravity and spring-loaded safety shutter over the direct beam, (iv) an electrical interlock to the shutter solenoid by camera movement, (v) a readily visible shutter knob, (vi) a fail-safe green lamp for indication that the electromagnetic shutter is closed and (vii) easy movement of the filter disk.