Case History Fitness-for-Service Assessment of Cyclic Catalytic Reformer Motor Operated Valves in the Petrochemical Industry

2011 ◽  
Author(s):  
Nick A. Carr ◽  
Kraig S. Shipley ◽  
David J. Dewees
Keyword(s):  
Ambient Temperature ◽  
Thermal Shock ◽  
Case History ◽  
Petrochemical Industry ◽  
Large Diameter ◽  
Catalyst Regeneration ◽  
Process Flow ◽  
Valve Body ◽  
Catalytic Reformer

Reactors of cyclic catalytic reformers require catalyst regeneration about every 7 days (∼50 cycles per year). To facilitate the in situ regeneration, large diameter motor operated valves (MOV) are used (typically Class 600 NPS 8 to NPS 16 API 600 gate block valves). Double block-n-bleed arrangements of the MOVs are used to assure isolation of the 350 psig 960°F process and regeneration media. The regeneration MOVs will be closed and in isolation for up to 4 days and can reach temperatures close to ambient depending on their distance from the process flow. Once the MOVs are swung open, the valve body quickly transitions from ambient temperature to 960°F over a matter of minutes. Such an extreme thermal shock has historically led to a number of cracks in the MOV valve bodies. With each unit having over 50 MOVs, it becomes expensive and time consuming to open every MOV at a scheduled turnaround, inspect, and repair any cracking noticed.

SEM of non-coated hepatocellular cytoskeleton of perfused livers

1984 ◽  
Vol 42 ◽  
pp. 306-307
Author(s):  
S.W. French ◽  
N.C. Benson ◽  
C. Davis-Scibienski
Keyword(s):  
Ambient Temperature ◽  
Critical Point ◽  
Protease Inhibitors ◽  
Metal Deposition ◽  
Heat Damage ◽  
Detergent Extraction ◽  
Cytoskeletal Elements ◽  
Triton X ◽  
Excised Tissue

Previous SEM studies of liver cytoskeletal elements have encountered technical difficulties such as variable metal coating and heat damage which occurs during metal deposition. The majority of studies involving evaluation of the cell cytoskeleton have been limited to cells which could be isolated, maintained in culture as a monolayer and thus easily extracted. Detergent extraction of excised tissue by immersion has often been unsatisfactory beyond the depth of several cells. These disadvantages have been avoided in the present study. Whole C3H mouse livers were perfused in situ with 0.5% Triton X-100 in a modified Jahn's buffer including protease inhibitors. Perfusion was continued for 1 to 2 hours at ambient temperature. The liver was then perfused with a 2% buffered gluteraldehyde solution. Liver samples including spontaneous tumors were then maintained in buffered gluteraldehyde for 2 hours. Samples were processed for SEM and TEM using the modified thicarbohydrazide procedure of Malich and Wilson, cryofractured, and critical point dried (CPD). Some samples were mechanically fractured after CPD.

scholarly journals Back Cover: In Situ Observation of Non‐Classical 2‐Norbornyl Cation in Confined Zeolites at Ambient Temperature (Angew. Chem. Int. Ed. 9/2021)

2021 ◽  
Vol 60 (9) ◽  
pp. 4952-4952
Author(s):  
Xiaomin Tang ◽  
Wei Chen ◽  
Xianfeng Yi ◽  
Zhiqiang Liu ◽  
Yao Xiao ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
In Situ Observation ◽  
Back Cover

scholarly journals Phase Transition and Coefficients of Thermal Expansion in Al2−xInxW3O12 (0.2 ≤ x ≤ 1)

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4021
Author(s):  
Andrés Esteban Cerón Cerón Cortés ◽  
Anja Dosen ◽  
Victoria L. Blair ◽  
Michel B. Johnson ◽  
Mary Anne White ◽  
...  
Keyword(s):  
Phase Transition ◽  
Thermal Expansion ◽  
Thermal Shock ◽  
Monoclinic Phase ◽  
Ceramic Materials ◽  
Precipitation Method ◽  
Scanning Calorimetry ◽  
Orthorhombic Crystal ◽  
Co Precipitation

Materials from theA2M3O12 family are known for their extensive chemical versatility while preserving the polyhedral-corner-shared orthorhombic crystal system, as well as for their consequent unusual thermal expansion, varying from negative and near-zero to slightly positive. The rarest are near-zero thermal expansion materials, which are of paramount importance in thermal shock resistance applications. Ceramic materials with chemistry Al2−xInxW3O12 (x = 0.2–1.0) were synthesized using a modified reverse-strike co-precipitation method and prepared into solid specimens using traditional ceramic sintering. The resulting materials were characterized by X-ray powder diffraction (ambient and in situ high temperatures), differential scanning calorimetry and dilatometry to delineate thermal expansion, phase transitions and crystal structures. It was found that the x = 0.2 composition had the lowest thermal expansion, 1.88 × 10−6 K−1, which was still higher than the end member Al2W3O12 for the chemical series. Furthermore, the AlInW3O12 was monoclinic phase at room temperature and transformed to the orthorhombic form at ca. 200 °C, in contrast with previous reports. Interestingly, the x = 0.2, x = 0.4 and x = 0.7 materials did not exhibit the expected orthorhombic-to-monoclinic phase transition as observed for the other compositions, and hence did not follow the expected Vegard-like relationship associated with the electronegativity rule. Overall, compositions within the Al2−xInxW3O12 family should not be considered candidates for high thermal shock applications that would require near-zero thermal expansion properties.

scholarly journals Avaliação de Tratamentos de Superação de Dormência em Sementes do Delonix regia (Boger ex Hook.) Raf coletadas no Horto Florestal Tote Garcia, Cuiabá, Mato Grosso

2017 ◽  
Vol 21 (1) ◽  
pp. 48
Author(s):  
Ana Carolina Amorim Marques ◽  
Osvaldo Borges Pinto Junior ◽  
Vera Lucia Lopes Vieira
Keyword(s):  
Ambient Temperature ◽  
Thermal Shock ◽  
Environmental Conditions ◽  
Economic Value ◽  
Mato Grosso ◽  
Delonix Regia ◽  
Breaking Dormancy ◽  
Manual Counting ◽  
The Family ◽  
Temperature Water

A árvore Delonix regia (flamboyant) pertence à família Fabaceae, subfamília Caesalpinioideae, originário da ilha de Madagascar. Tem potencial valor econômico ornamental, pois se trata de uma espécie extremamente florífera e exuberante, indicada para programas de arborização, como parques, praças e jardins, sendo inadequada para ruas e avenidas, devido a suas raízes serem caracterizadas como superficiais. Essa espécie exótica, adaptada as condições ambientais de clima tropical, tem porte de 10 – 12m de altura, de tronco volumoso, espesso, com raízes tabulares. Por apresentar características de dormência tegumentar, este trabalho teve objetivo de avaliar alguns tratamentos para superação de dormência das sementes do Delonix regia. O experimento foi do tipo quantitativo, em que as sementes foram submetidas a três tratamentos e uma testemunha, em um total de 4 tratamentos, com 75 sementes cada. A emergência foi observada in locu, por meio de contagem manual. Os tratamentos utilizados foram: escarificação mecânica com lixa (n° 120); imersão em água em temperatura ambiente por 72 horas, choque térmico com imersão das sementes em água a 80 ºC por 05 min e a testemunha em que não houve nenhuma intervenção. Observou-se que a escarificação mecânica e o choque térmico proporcionaram os melhores resultados para superação de dormência das sementes do Delonix regia.Palavras-chave: Paisagismo. Dormência. Emergência.AbstractThe tree Delonix regia (flamboyant) belongs to the family Fabaceae, subfamily Caesalpinioideae, originally from the island of Madagascar. It has the potential ornamental economic value, because it is an extremely floriferous and exuberant species suitable for reforestations programs such as parks,and gardens, being inappropriate for streets and avenues, because its roots are characterized as superficial. This exotic species, adapted to the environmental conditions of tropical climate, reaches size of 10-12 m tall, large trunk, dense with tabular roots. It is renowned for being an extremely floriferous and exuberant species. By presenting cutaneous numbness characteristics, the objective of this study was to evaluate some treatments to overcome dormancy of seeds Delonix regia. The experiment was the quantitative type, in which the seeds were subjectedto three treatments and a control, a total of 4 treatments with 75 seeds each. The emergence was observed in locus through manual counting. The treatments were mechanical scarification with sandpaper (#120); immersion in ambient temperature water for 72 hours, thermal shock deep soaking the seeds in water at 80 °C for 5 minutes and the control, which had no intervention. It was observed that the mechanical scarification and thermal shock provided the best results for breaking dormancy of seeds Delonix regia.Keywords: Landscaping. Emergency Seedling. Dormancy

Water Shut-Off Using an Inflatable Composite Sleeve Polymerised In-Situ. A Case History on Forties Delta

1998 ◽  
Author(s):  
J. Leighton ◽  
J.L. Saltel ◽  
J. Morrison ◽  
R. Welch ◽  
J. Pilla
Keyword(s):  
Case History

Vacuum steam treatment of Metrosideros polymorpha logs for eradication of Ceratocystis huliohia and C. lukuohia

Plant Disease ◽  
2021 ◽  
Author(s):  
Jennifer Juzwik ◽  
Marc A Hughes ◽  
Zhanghing Chen ◽  
Anna Yang ◽  
Lisa Keith ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Efficient Method ◽  
Plant Material ◽  
Large Diameter ◽  
Steam Treatment ◽  
Metrosideros Polymorpha ◽  
Forest Trees ◽  
Phytosanitary Treatment ◽  
C 30 ◽  
Time Required

A new and devastating disease, rapid ohia death (ROD), in Hawaii led to a state quarantine that regulates inter-island transport of ohia wood and plant material to prevent spread of the causal pathogens. Heat treatments of ohia logs in commercial trade were considered for phytosanitary treatment. Vacuum steam (VS) was evaluated for its ability to eradicate the pathogens, Ceratocystis lukuohia and/or C. huliohia, in main stem logs from ROD-affected forest trees. Replicate loads of three de-barked logs (24 to 43 cm diameter; 1.7 to 2.0 m long) were VS-treated at 56° C for 30 min (5 loads) or 60° C for 60 min (4 loads) at a sapwood depth equal to 70% of log radius. Percent isolation of Ceratocystis from VS and ambient temperature logs prior to treatment and summarized by source tree ranged from 12 to 66% and 6 to 31% based on carrot baiting assays of tissue taken from outer and inner sapwood, respectively. No viable Ceratocystis was detected in either sapwood locations for the 60° C/ 60 min schedule or for the inner locations for the 56° C/ 30 min schedule following treatment. Only one subsample (0.48%, n=208) of the latter schedule treatment yielded Ceratocystis. Time required for treatment ranged from 7.4 to 15 h for the 56° C/ 30 min schedule and from 8.6 to 19.2 h for the 60° C/ 60 min schedule. These results demonstrate VS is an effective and efficient method for treating large diameter ohia logs that mill owners and regulatory plant pathologists may consider for use in Hawaii.

Static Pressure-Volume Curves for the Lung of the Frog (Rana Pipiens)

1978 ◽  
Vol 76 (1) ◽  
pp. 149-165 ◽  
Author(s):  
G. M. HUGHES ◽  
G. A. VERGARA
Keyword(s):  
Volume Change ◽  
Rana Pipiens ◽  
Static Pressure ◽  
Large Diameter ◽  
The Difference ◽  
Isolated Lungs ◽  
Precise Role ◽  
Different Parts

1. Static pressure/volume curves have been determined for isolated frog lungs inflated with either air or saline. In both cases a hysteresis was present: the pressure required to produce unit change of volume being greater during inflation than deflation. 2. The pressure necessary for a given volume change was less for the saline-filled than the air-filled lungs. The difference between these curves is due to the surface tension at the air/lung interface. 3. Pressure/volume curves for air-filled lungs in situ were similar to curves for isolated lungs. However, a greater pressure was required for the same volume change during both inflation and deflation. 4. Compliance was calculated from different parts of air pressure/volume curves and gave values greater than those obtained using similar calculations for higher vertebrates. 5. These observations support other evidence for the presence of a surfactant in the lung lining of frogs in spite of the relatively large diameter of their ‘alveoli.’ The precise role of such a lining is uncertain and it is concluded that similar forces may be involved during the inflation and deflation of lungs of frogs and higher vertebrates in spite of differences in gross morphology.

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