The Residual Bolt Force and the Sealing Performance of Flanged Connections With Expanded PTFE Gaskets (Based on Test Results for One Year)

2012 ◽  
Author(s):  
Takashi Kobayashi ◽  
Taiki Hagiri ◽  
Kengou Nishiura ◽  
Masaaki Hiratsuka ◽  
Katsutoyo Itoi
Keyword(s):  
Thermal Expansion ◽  
Room Temperature ◽  
Early Stage ◽  
Thermal Characteristic ◽  
Temperature Dependency ◽  
Test Results ◽  
Viscoelastic Characteristic ◽  
Sealing Performance ◽  
One Year

It is known that bolt forces reduce significantly after tightening bolted flanged connections in which expanded PTFE gaskets are used. Bolts are often post-tightened in practice after initial tightening to compensate for the reduction of bolt forces. The viscoelastic characteristic of expanded PTFE gaskets is thought to be the main cause for the phenomenon. Some gasket users are not confident whether the bolt forces remain above a minimum required gasket load until next maintenance. However, the long term characteristics of the residual bolt forces and the sealing performance of flanged connections have not been clarified yet. In this study, using flanged connections with expanded PTFE gaskets, the reduction of bolt forces and the change in the sealing performance were measured at room temperature for one year. Based on the test results, the residual bolt force and the sealing performance were studied. It was clarified that bolt forces converges to a certain level at early stage within almost 1000 hours. After that, the bolt forces were significantly affected by the ambient temperature change. This is because the thermal expansion of PTFE material is high and also the thermal characteristic of PTFE material has a temperature dependency. It was confirmed that although the bolt force reduced significantly at early stage, it is maintained in long-term. The sealing performance was improved due to the increased compression of gasket.

Effects of Post-Tightening on the Residual Bolt Force and the Sealing Performance of Flanged Connections With PTFE Gaskets (Long Term Effects at Room Temperature)

2011 ◽  
Author(s):  
Taiki Hagiri ◽  
Takashi Kobayashi ◽  
Kengou Nishiura ◽  
Kazuaki Uchiyama
Keyword(s):  
Room Temperature ◽  
Test Results ◽  
Long Term Effects ◽  
Viscoelastic Characteristic ◽  
Sealing Performance ◽  
Nominal Size ◽  
Gasket Material

It is known that bolt forces reduce significantly after tightening bolted flanged connections in which expanded PTFE gaskets are used. Bolts are often post-tightened in practice after a while to compensate for the reduction of bolt forces. The viscoelastic characteristic of expanded PTFE gaskets is the main cause for the phenomenon. However, the long term effects of the post-tightening on the residual bolt forces and the sealing performance of flanged connections have not been clarified yet. In this study, two sets of flanged connections (2 inch in nominal size), in which PTFE gaskets were used, were prepared and tightened. One of the flanges was post-tightened after a designated time. The reduction of bolt forces and the change in the sealing performance were measured for about two months. The results were compared with those of flanges without post-tightening. Based on the test results, the effectiveness of post-tightening was discussed from the viewpoint of the residual bolt force and the sealing performance. It has been clarified that the effectiveness of post-tightening depends on gasket material and that post-tightening is effective for expanded PTFE gaskets.

Clinical features, treatment, and outcome of dogs with Coccidioides osteomyelitis

2022 ◽  
pp. 1-8
Author(s):  
Stephanie L. Shaver ◽  
Daniel S. Foy ◽  
Todd D. Carter
Keyword(s):  
Electronic Medical Records ◽  
Medical Records ◽  
Clinical Signs ◽  
Test Results ◽  
Serologic Test ◽  
Rapid Improvement ◽  
Radiographic Appearance ◽  
One Year ◽  
Positive Results

Abstract OBJECTIVE To describe signalment, clinical signs, serologic test results, treatment, and outcome of dogs with Coccidioides osteomyelitis (COM) and to compare those findings with findings for dogs with osteosarcoma (OSA). ANIMALS 14 dogs with COM and 16 dogs with OSA. PROCEDURES Data were retrospectively gathered from electronic medical records. RESULTS Dogs with COM were younger and weighed less than dogs with OSA. Six dogs with COM had appendicular lesions, 5 had axial lesions, and 3 had both appendicular and axial lesions; 9 had monostotic disease, and 5 had polyostotic disease. Axial lesions and nonadjacent polyostotic disease were more common in dogs with COM than in dogs with OSA, but radiographic appearance was not different between the 2 groups. Median IgG titer at diagnosis of COM was 1:48 and was significantly decreased after 6 and 12 months of treatment. Percentage of dogs with COM that had clinical signs was significantly decreased after 1, 3, 6, and 12 months of treatment. One year after initiation of treatment, 9 of 9 dogs were still receiving fluconazole and 8 of 9 dogs had positive results for serum IgG titer testing. CLINICAL RELEVANCE Dogs with COM typically had a rapid improvement in clinical signs after initiating treatment with fluconazole but required long-term antifungal treatment. Dogs with COM differed from dogs with OSA, but radiographic features had a great degree of overlap between groups, confounding the ability to make a diagnosis on the basis of diagnostic imaging alone.

ADDRESS (ADministration of DRotrecogin alfa [activated] in Early stage Severe Sepsis) long-term follow-up: One-year safety and efficacy evaluation*

2007 ◽  
Vol 35 (6) ◽  
pp. 1457-1463 ◽  
Author(s):  
Pierre-Francois Laterre ◽  
Edward Abraham ◽  
Jonathan M. Janes ◽  
Benjamin L. Trzaskoma ◽  
Nancy L. Correll ◽  
...  
Keyword(s):  
Severe Sepsis ◽  
Drotrecogin Alfa ◽  
Early Stage ◽  
Efficacy Evaluation ◽  
Safety And Efficacy ◽  
Drotrecogin Alfa Activated ◽  
Long Term Follow Up ◽  
One Year

The Effect of the Thermal Expansion Coefficient on the Sealing Performance of Pipe Flange Connections With NiTi Shape Memory Alloy Gaskets

2006 ◽  
Author(s):  
Yoshio Takagi ◽  
Teruhisa Tatsuoka ◽  
Toshiyuki Sawa
Keyword(s):  
Thermal Expansion ◽  
Shape Memory ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Research Council ◽  
Nickel Titanium ◽  
Niti Shape Memory Alloy ◽  
Ti Alloy ◽  
Sealing Performance

Due to the long-term durability and the excellent resistance to aging degradation, metal gaskets are expected to endure a longer life compared to conventional polymer gaskets. However, the nature of high elastic modulus of the metal reduces the sealing performance at interface. The authors have paid attention to the super elasticity of the shape memory alloys like Nickel-Titanium (Ni-Ti) alloy and evaluated its applicability to a gasket. In the process, leakage tests of the flange connections with Ni-Ti alloy gaskets were done and the sealing performance was evaluated with the new gasket constants and the tightness parameter proposed by PVRC (Pressure Vessel Research Council, ASME). The results revealed that Ni-Ti alloy gaskets showed a superior sealing performance to the conventional aluminum gasket. However, the thermal expansion coefficient of Ni-Ti alloy is smaller than that of stainless steel of which the flange is made. The increase in temperature of the flange like 20 °C to 40 °C accordingly induced a slight degradation of the sealing performance. In this paper, the effect of the change in temperature on the sealing performance of the pipe flange connections with Ni-Ti alloy gasket was numerically evaluated with the measured thermal expansion coefficient. Moreover, the effect of the clamped temperature on the sealing performance was evaluated taking into account the temperature dependence of the mechanical properties of Ni-Ti alloy.

Practical Evaluation of PTFE Thermal Behavior Using the Hot Blowout Thermal Cycling Test

2012 ◽  
Author(s):  
Anita R. Bausman ◽  
A. Fitzgerald (Jerry) Waterland
Keyword(s):  
Thermal Cycling ◽  
Compressive Load ◽  
Temperature Limit ◽  
Cycling Performance ◽  
Current Status ◽  
Test Results ◽  
Sealing Performance ◽  
Practical Evaluation ◽  
Bolted Flange

Differential thermal expansion between polytetrafluoroethylene (PTFE) gasket materials and metallic flange/bolt systems, combined with thermally influenced creep relaxation characteristics of all PTFEs, creates limitations in the ability of some PTFE gasket materials to provide long term, reliable sealing performance in process or thermal cycling applications. ASTM F-36 gasket recovery data is sometimes used to assess a gasket’s thermal cycling capabilities; however, it is a poor means of establishing suitability for cycling performance as it is a short duration, ambient temperature test that measures recovery, or springback, of the gasket after the compressive load has been completely released. In order to provide a direct qualification of thermal cycling performance and capabilities, the Hot Blowout Thermal Cycling (HOBTC) test was developed under the guidance of the PVRC (Pressure Vessel Research Council)Bolted Flange Connection Committee as part of the 1995 PTFE Gasket Protocol. The HOBTC test results provide a practically applicable temperature limit under which the tested material, typically a PTFE, can operate safely. In addition, test data reported graphically provide additional insight about the long term behavior of the PTFE material. This paper reviews the current status of the HOBTC test, in the process of being made into an ASTM standard, and practical application of test results to achieve reliable gasket performance.

scholarly journals Norwalk-Like Virus Sequences in Mineral Waters: One-Year Monitoring of Three Brands

2002 ◽  
Vol 68 (4) ◽  
pp. 1925-1931 ◽  
Author(s):  
Christian Beuret ◽  
Dorothe Kohler ◽  
Andreas Baumgartner ◽  
Thomas M. Lüthi
Keyword(s):  
Reverse Transcriptase ◽  
Water Samples ◽  
Room Temperature ◽  
Mineral Water ◽  
Mineral Waters ◽  
Long Term Stability ◽  
Test Sensitivity ◽  
Monitoring Study ◽  
One Year

ABSTRACT In a recent study, RNA with nucleotide sequeces specific for “Norwalk-like viruses” (NLV) was detected in 11 different brands of European mineral waters. To clarify this finding, a 1-year monitoring study was conducted. Samples of three European brands of mineral water without gas were monitored weekly by reverse transcriptase PCR using generic and genogroup-specific oligonucleotides. Additional analyses were performed to investigate a possible correlation between NLV sequence contamination and mineral water lot numbers, the long-term stability (persistence) of NLV sequences in mineral water, and the level of contamination. NLV sequences were detected in 53 of 159 samples analyzed (33%) and belonged entirely to genogroup II. Although all NLV strains identified were closely related, three mineral water brand-specific clusters could be identified for both primer systems by sequencing. Analyses of second samples from lots previously shown to be positive for NLV sequences gave corresponding results in 45 of 53 cases (85%) (within a six-pack). NLV persistence was tested by analyzing 10 positive samples after 6 and 12 months of storage in darkness at room temperature. After 6 months, all samples remained positive; after 12 months, 9 of 10 samples were still positive for NLV sequences. No NLV sequences could be detected by analysis of 0.1-liter aliquots of 53 samples shown to be positive by testing of 1-liter volumes. Based on this fact and a test sensitivity of approximately 10 viral units, levels of contamination in positive mineral water samples were estimated to be in the range of 10 to 100 genomic equivalents per liter.

scholarly journals Biologging of emperor penguins – attachment techniques and associated deployment performance

2021 ◽  
Author(s):  
Aymeric Houstin ◽  
Daniel P. Zitterbart ◽  
Alexander Winterl ◽  
Sebastian Richter ◽  
Víctor Planas-Bielsa ◽  
...  
Keyword(s):  
Early Stage ◽  
Weddell Sea ◽  
Emperor Penguin ◽  
Marine Animals ◽  
Emperor Penguins ◽  
Negative Impacts ◽  
One Year ◽  
Sea Area ◽  
The Three Rs

An increasing number of marine animals are equipped with biologgers, to study their physiology, behaviour and ecology, often for conservation purposes. To minimise the impacts of biologgers on the animals′ welfare, the Refinement principle from the Three Rs framework (Replacement, Reduction, Refinement) urges to continuously test and evaluate new and updated biologging protocols. Here, we propose alternative and promising techniques for emperor penguin (Aptenodytes forsteri ) capture and on–site logger deployment that aim to mitigate the potential negative impacts of logger deployment on these birds. We equipped adult emperor penguins for short–term (GPS, Time–Depth Recorder (TDR)) and long–term (i.e. planned for one year) deployments (ARGOS platforms, TDR), as well as juvenile emperor penguins for long-term deployments (ARGOS platforms) in the Weddell Sea area where they had not yet been studied. We describe and qualitatively evaluate our protocols for the attachment of biologgers on–site at the colony, the capture of the animals and the recovery of the devices after deployment. We report unprecedented recaptures of long–term equipped adult emperor penguins (50% of equipped individuals recaptured after 290 days). Our data demonstrate that the traditional technique of long–term attachment by gluing the biologgers directly to the back feathers is detrimental to the birds. It causes excessive feather breakage and the loss of the devices at an early stage. We therefore propose an alternative method of attachment for back–mounted devices. This technique led to successful year–round deployments on 37.5% of the equipped juveniles. Finally, we also disclose the first deployments of leg–bracelet mounted TDRs on emperor penguins. Our findings highlight the importance of monitoring potential impacts of biologger deployments on the animals and the need to remain critical towards established and new protocols.

Adjuvant (adj) bevacizumab (B) plus dose-dense (dd) doxorubicin/cyclophosphamide (AC) followed by nanoparticle albumin- bound paclitaxel (nab-p) in early stage breast cancer (BC) patients (pts): Cardiac safety

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 567-567 ◽  
Author(s):  
M. N. Dickler ◽  
T. Traina ◽  
K. Panageas ◽  
R. Steingart ◽  
C. Dang ◽  
...  
Keyword(s):  
Cardiac Death ◽  
Early Stage ◽  
Standard Of Care ◽  
Cardiac Monitoring ◽  
Cardiac Safety ◽  
Lv Dysfunction ◽  
Long Term Follow Up ◽  
One Year ◽  
Dose Dense

567 Background: Dose dense, q2 wk AC-paclitaxel (T) is superior to q3 wk therapy (Rx) (Citron, JCO 2003). The risk of congestive heart failure (CHF) with ddAC-T is not increased at <1%. In MBC, B improves PFS when added to T (Miller, SABCS 2005). It is unclear if doxorubicin plus B increases risk of CHF. Hence, we are testing the cardiac safety of ddAC-nab-p with concurrent B as adj therapy. Based upon the accepted cardiac event (CE) rate of ≤4% in trials with adj trastuzumab (an agent with known cardiac toxicity), we designed this study with similar monitoring & tolerability thresholds. The primary endpoint is cardiac safety, defined as discontinuation of B due to cardiac death from LV dysfunction or symptomatic CHF (dyspnea and LVEF<50%). Secondary endpoints: toxicity, disease-free & overall survival. Methods: Eligible pts have resected HER2(-) BC and normal LVEF. Rx consists of q2wk AC (60/600 mg/m2) ×4 then nab-p (260 mg/m2) x4 with pegfilgrastim on Day 2 plus B for one year (10mg/kg IV q2wk ×8 with chemoRx then B 15mg/kg q3wk); radiation & endocrine Rx per standard of care. MUGA obtained at baseline & mos. 2, 6, 9, 18. Pts with significant asymptomatic ↓LVEF during Rx may have B held per protocol. These pts are not counted as CEs but will have long-term cardiac monitoring. Accrual goal is 75 pts. If ≥3 CE (∼4.7%) or >1 cardiac death from LV dysfunction, B + ddAC-nab-p will not be considered safe. Results: 44 pts have enrolled, median (med) age 46.5 yrs (33–67). 28 pts have baseline & month 2 LVEF data: med baseline LVEF 68% (61–82), med LVEF at mo. 2 after ddAC+B 68% (53–75); 1 pt had an 18 point asymptomatic drop to 53% - B held but reinitiated in 4 wks with repeat LVEF 63%. 12 pts completed nab-p+B but none have reached the 6 mo. MUGA. Rx-related Gr 3/4 toxicity: neutropenia gr4 (6.8%), diarrhea gr3 (2.3%), hypertension gr3 (2.3%), neuropathy gr 3 (2.3%), fatigue gr 3 (2.3%), mucositis gr 3 (2.3%). 4 pts have withdrawn from study Rx, but only 1 due to toxicity including gr3 fatigue, mucositis & neuropathy. Conclusions: No LV dysfunction has been observed with B + ddAC-nab-p; this trial is on-going. Long-term follow-up and analysis of troponin, renin and circulating endothelial & tumor cells are planned. No significant financial relationships to disclose.

LONG-TERM PLANT-GROWING PERFORMANCE OF POROUS CONCRETE WITH VARYING AMOUNTS OF OYSTER SHELL AGGREGATE

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Itaru Horiguchi ◽  
Yoichi Mimura
Keyword(s):  
Oyster Shell ◽  
Crushed Stone ◽  
Summer Drought ◽  
Test Results ◽  
Porous Concrete ◽  
Hiroshima Prefecture ◽  
One Year

Oysters are produced in each district in Japan, and Hiroshima Prefecture is especially famous as a high producing district. Accordingly, the production of oysters has created oyster shells as a by-product. Oyster shell porous concrete (OyPoC) is porous concrete using crushed oyster shells as aggregates. In previous researches, it was found that OyPoC with finely crushed oyster shell had high plant-growing performance. However, all of the planting test periods were less than three months; the long-term plant-growing performance of OyPoC had not been clear. In this study, the plant-growing performance of OyPoC was investigated by conducting long-term planting tests over one year. OyPoC and hybrid porous concrete (HyPoC), which was combined with OyPoC and crushed stone porous concrete, were prepared for the planting tests. From the test results, the plant-growing performance of OyPoC was higher than that of HyPoC because OyPoC had much higher oyster shell aggregate than HyPoC. In contrast, there was a risk of the severe summer drought withering the grass on OyPoC and the watering in the summer was found to be important.

A Determination Method of Bolt Preload for Bolted Pipe Flange Connections With Metal Gaskets Under Internal Pressure

2015 ◽  
Author(s):  
Koji Kondo ◽  
Toshiyuki Sawa
Keyword(s):  
Internal Pressure ◽  
Room Temperature ◽  
Bolted Joints ◽  
Test Results ◽  
Bolt Preload ◽  
Sealing Performance ◽  
Bolted Flange ◽  
The Given ◽  
Outside Diameter ◽  
Better Than

FEM calculations and leakage experiments are carried out for bolted flanged connections with metal flat gaskets. It is found that the sealing performance of bolted flanged connections with raised face metal gaskets under internal pressure is improved significantly when the contact gasket stress reaches the gasket yield stress. In our FEM calculations it is demonstrated that the contact gasket stress at the outside diameter is bigger than that at the inside diameter due to the flange rotation. It is also found from the leakage test results and the FEM calculations that the sealing performance of the bolted flange connections with metal flat gasket is better than that of the metal gasket in platen device tests,. In addition, the contact stress in the joints with RTJ (ring type joint) gasket is examined and 4 stress peaks on the oval type and 8 peaks on the octagonal type are found. From the obtained results, a method for determining the bolt preloads in the bolted joints using flat metal gaskets and RTJ gaskets under internal pressure is proposed taking account the given allowable leak rate. Finally, the leak rates for bolted flanged connections tightened under internal pressure are compared with the experimental results. The new method can be proposed for determining the bolt preload for bolted flange connections with metal gaskets under internal pressure at room temperature.

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