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Artykuły w czasopismach na temat "CLOSITE 30 B"
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Osipovsky, V. M. "Closure of the fecal fistula by bowel evagination". Kazan medical journal 32, nr 7 (20.09.2021): 615. http://dx.doi.org/10.17816/kazmj80653.
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B-naya Cher va Maria, 57 years old, Russian, peasant woman, s. Svinogorsk, Yelabuga region, was admitted to the surgical department of Kosteneevskaya hospital on 20 / X 30 for a persistent non-healing fecal fistula in the left groin area.
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Moldenhauer, Julie S., Shelly Soni, Jillian Jatres, Juliana Gebb, Nahla Khalek, Christina Paidas Teefey, Mark P. Johnson i in. "Open Fetal Surgical Outcomes for Myelomeningocele Closure Stratified by Maternal Body Mass Index in a Large Single-Center Cohort". Fetal Diagnosis and Therapy 47, nr 12 (2020): 889–93. http://dx.doi.org/10.1159/000511781.
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<b><i>Background:</i></b> Open maternal-fetal surgery for in utero closure of myelomeningocele (MMC) has become an accepted treatment option for prenatally diagnosed open neural tube defects. Historically, this option has been limited to women with BMI < 35 due to concern for increasing complications in patients with obesity. <b><i>Objective:</i></b> The aim of this study was to evaluate maternal, obstetric, and fetal/neonatal outcomes stratified by maternal BMI classification in women who undergo open maternal-fetal surgery for fetal myelomeningocele (fMMC) closure. <b><i>Methods:</i></b> A single-center fMMC closure registry was queried for maternal demographics, preoperative factors, fetal surgery outcomes, delivery outcomes, and neonatal outcomes. Data were stratified based on maternal BMI: <30, 30–34.99, and ≥35–40, corresponding to normal weight/overweight, obesity class I, and obesity class II. Statistical analysis was performed using statistical software SAS v.9.4 (SAS Institute Inc., Cary, NC, USA). <b><i>Results:</i></b> A total of 264 patients were analyzed, including 196 (74.2%) with BMI <30, 54 (20.5%) with BMI 30–34.99, and 14 (5.3%) with BMI ≥ 35–40. Maternal demographics and preoperative characteristics were similar among the groups. Operative time increased with increasing BMI; otherwise, perioperative outcomes were similar among the groups. Obstetric and neonatal outcomes were similar among the groups. <b><i>Conclusion:</i></b> Increasing maternal BMI did not result in a negative impact on maternal, obstetric, and fetal/neonatal outcomes in a large cohort of patients undergoing open maternal-fetal surgery for fMMC closure. Further study is warranted to determine the generalizability of these results.
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Dr. Niaz Ali, Miss. Rafia Naz Ali i Miss. Johar Wajahat. "Education in Pakistan: Are the Articles 25A and 37(b) Closing the Gender Gap in KP Province?" Research Journal of Social Sciences and Economics Review (RJSSER) 2, nr 1 (7.03.2021): 30–35. http://dx.doi.org/10.36902/rjsser-vol2-iss1-2021(30-35).
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This study aims to analyze the effectiveness of articles 25A and 37(b) in closing the gender gap in Pakistan's KP province. This stated Article explains the right to free and compulsory education up to the secondary level. The literature review has shown that two types of factors can affect achieving the goals defined by articles 25A and 37(b). Article 25A provides constitutional efforts to provide free and compulsory education in the chapter of fundamental rights. Article 37(b) enjoined the respective institutions' obligation to remove illiteracy and provide free and compulsory education to the secondary level within the minimum possible period. Clause (f) of the same Article declares how the State will enable Pakistani citizens to participate in national life through education. These claims were named as "efforts." The efforts are under human control. Some factors act against these stated efforts, known as "circumstances," which are natural and out of human control, such as gender gaps, poverty, Pashtunwali culture, etc. In Pakistan, the "efforts" are made to achieve the stated Articles' targets. Still, no policy was developed to answer the "circumstances." This attitude extends hurdles in educating KP girls. Suggestions were made to eradicate these "circumstances" entirely or partially to the extent possible. If these "circumstances" were removed, the girls' ratio of gross enrolment rate would be at least at a high level as boys, and thus the vision explained by the stated Articles can be achieved.
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Mittal, Sushil, Harnam Singh, Gurpreet Singh, Anand Munghate, Anjna Garg i Manish Yadav. "A comparative study between single layer versus double layer closure in ileostomy reversal". Asian Journal of Medical Sciences 6, nr 2 (15.09.2014): 43–46. http://dx.doi.org/10.3126/ajms.v6i2.10080.
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Background: Ileal perforation peritonitis is a common surgical emergency in the Indian subcontinent and in tropical countries. Formation of an intestinal stoma is frequently a component of surgical intervention for diseases of the small bowel. The technique for stoma reversal has remained controversial is the use of either one or two layers of sutures for anastomosis.Methods: Sixty patients with ileostomy were taken for study .These patients divided in two groups A and B, 30 each. These patients were taken up for ileostomy closure in single layer (group A) (n-30) &double layer (group B) (n-30). Results: 60 Patients of ileostomy were studied, divided equally in 2 groups, A decreased intra operative time was seen in Group A when compared with Group B with no any significant comparative complication in these groups. Conclusion: Two-layer anastomosis for ileostomy closure offers no definite advantage over single layer anastomosis in terms of postoperative leak and other complications. Single layer ileostomy closure technique is safe, easy to perform and simply to taught. Considering duration of the anastomosis procedure and medical expenses single-layer intestinal anastomosis may prove the choice of procedure for most of the surgeons. DOI: http://dx.doi.org/10.3126/ajms.v6i2.10080Asian Journal of Medical Sciences Vol.6(2) 2015 44-47
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D., Euvalingam, i Sendhil Nathan. "Comparative study of wound sequlae in layer closure and retention closure of midline laparotomy". International Surgery Journal 6, nr 9 (28.08.2019): 3316. http://dx.doi.org/10.18203/2349-2902.isj20194072.
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Background: Layered closure of the abdomen has been considered to be ideal until recently however single layer mass (retention) closure technique, in which all the layers of the abdominal wall are closed in single layer is being increasingly used by surgeons. We conducted this study to analyze outcome measures in patients in whom wound closure was done by retention closure and layered closure.Methods: This was a prospective comparative study in which 60 patients undergoing elective or emergency laparotomy were included on the basis of a predefined inclusion and exclusion criteria. In 30 cases (50%) layer closure was done whereas in remaining 30 (50%) patients retention closure technique was used. Major outcome measures studied were time required for wound closure and post-operative complications.Results: Out of 60 studied cases there were 42 (70%) males and 18 (30%) females with M: F ratio of 1: 0.42.The time required for closure in layered suture group (group A) was 26.76±3.36 whereas in case of retention closure suturing it was 19.36±4.35. The difference was found to be statistically highly significant (p<0.0001). The complications rates were found to be statistically significantly higher in layer suturing (Group A) as compared to retention suture group (Group B).Conclusions: We conclude that retention suturing is preferable as compared to layered suturing in patients undergoing midline laparotomy in terms of time required for closure of wound and post-operative complication rates.
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Høg, E. "Tycho Astrometry from 30 Months of Satellite Mission". Symposium - International Astronomical Union 166 (1995): 61–68. http://dx.doi.org/10.1017/s007418090022785x.
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The Hipparcos satellite's star mapper gives photon counts in two spectral channels simultaneously, close to Johnson B and V. The transit times and the signal amplitudes for each star across two groups of four slits are derived and used for astrometry and photometry, respectively, and this constitutes the Tycho project. The present paper describes results of Tycho astrometric data processing, leading from the transit times to the astrometric parameters of the Tycho stars.Some 30 months of Tycho observations, i.e. about 80 percent of the Hipparcos-Tycho mission, have been used to produce a working catalogue of Tycho positions, proper motions and parallaxes of a million stars. The external errors of this preliminary catalogue have been determined by comparison of 98 000 stars common with a preliminary, but much more accurate Hipparcos catalogue. External systematic errors of positions and annual proper motions are less than 0.5 milliarcsecond (mas) and the accidental errors per star are about 30 mas rms at V = 10.5 mag, the median magnitude of the catalogue. It is concluded that a satisfactory accuracy has been achieved.
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Bordé, P., R. F. Díaz, O. Creevey, C. Damiani, H. Deeg, P. Klagyivik, G. Wuchterl i in. "Transiting exoplanets from the CoRoT space mission". Astronomy & Astrophysics 635 (marzec 2020): A122. http://dx.doi.org/10.1051/0004-6361/201732393.
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Aims. We report the discovery as well as the orbital and physical characterizations of two new transiting giant exoplanets, CoRoT-30 b and CoRoT-31 b, with the CoRoT space telescope. Methods. We analyzed two complementary data sets: photometric transit light curves measured by CoRoT, and radial velocity curves measured by the HARPS spectrometer. To derive the absolute masses and radii of the planets, we modeled the stars from available magnitudes and spectra. Results. We find that CoRoT-30 b is a warm Jupiter on a close-to-circular 9.06-day orbit around a G3V star with a semi-major axis of about 0.08 AU. It has a radius of 1.01 ± 0.08 RJ, a mass of 2.90 ± 0.22 MJ, and therefore a mean density of 3.45 ± 0.65 g cm−3. The hot Jupiter CoRoT-31 b is on a close-to-circular 4.63-day orbit around a G2 IV star with a semi-major axis of about 0.05 AU. It has a radius of 1.46 ± 0.30 RJ, a mass of 0.84 ± 0.34 MJ, and therefore a mean density of 0.33 ± 0.18 g cm−3. Conclusions. Neither system seems to support the claim that stars hosting planets are more depleted in lithium. The radii of both planets are close to that of Jupiter, but they differ in mass; CoRoT-30 b is ten times denser than CoRoT-31 b. The core of CoRoT-30 b would weigh between 15 and 75 Earth masses, whereas relatively weak constraints favor no core for CoRoT-31 b. In terms of evolution, the characteristics of CoRoT-31 b appear to be compatible with the high-eccentricity migration scenario, which is not the case for CoRoT-30 b. The angular momentum of CoRoT-31 b is currently too low for the planet to evolve toward synchronization of its orbital revolution with stellar rotation, and the planet will slowly spiral-in while its host star becomes a red giant. CoRoT-30 b is not synchronized either: it looses angular momentum owing to stellar winds and is expected reach steady state in about 2 Gyr. CoRoT-30 and 31, as a pair, are a truly remarkable example of diversity in systems with hot Jupiters.
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M., Devaprashanth, Srinivas N. M. i Akhihlandeshwari N. "Limberg flap versus primary closure in the treatment of pilonidal sinus: a randomised clinical study". International Surgery Journal 8, nr 8 (28.07.2021): 2388. http://dx.doi.org/10.18203/2349-2902.isj20213134.
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Background: Pilonidal sinus is a chronic disease usually involving the sacrococcygeal area. Various treatment modalities exist, yet few comparison studies exist to compare the efficacy of one modality over the other. Hence this randomized clinical study was undertaken as an attempt to compare the outcomes of pilonidal sinus following Limberg flap procedure and primary closure.Methods: 60 patients undergoing surgery for pilonidal sinus disease were considered for the study. 30 patients underwent excision and primary closure and 30 patients underwent Limberg flap repair. They were followed up for 1 year. Duration of hospital stay, duration of inability to work, postoperative infection, wound dehiscence, and postoperative recurrence in a follow up period were recorded. Descriptive statistics, chi- square tests and independent t-test are the statistical tools employed.Results: Mean age was 29.83±4.99 years. Male:female ratio was 5.66:1. The mean duration of hospitalization in group A was significantly less (p<0.05) than group B. The patients in group B returned early to routine work (21.56±3.92 days) as compared to 30.5±5.92 days in group A (p<0.05). 5 of 30 patients in group A and 2 of 30 in group B developed surgical site infection. (p>0.05. 4 patients developed wound dehiscence in group A only which was found to be statistically significant.Conclusions: Limberg flap in treatment of pilonidal sinus is associated with shorter hospitalization, early return to routine work and less wound dehiscence as compared with excision and primary closure. Wound infections are comparable with both the modalities.
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Ghaffar, Naeem, Muhammad Aslam Javed, Farooq Ahmad, Hina Khan, Muhammad Arshad i Kamran Khalid Khawaja. "Limberg Flap Versus Primary Midline Wound Closure in Treatment of Chronic Pilonidal Sinus Disease". Pakistan Journal of Medical and Health Sciences 16, nr 1 (18.01.2022): 219–20. http://dx.doi.org/10.53350/pjmhs22161219.
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Objective: Current study aims to compare the Limberg flap technique with primary midline wound closure to treat the chronic pilonidal sinus disease. Study design: A comparative study was done in Surgery Department Sir Ganga Ram Hospital Lahore from January 2020 to September 2021 Method: The sample size for the study is 60 patients who were regularly visiting the hospital due to PS disease. All the patients were divided into two groups A and B. Group A had 30 patients treated with the Limberg flap method and group B had 30 patients treated with primary midline wound closure. Before starting the treatment a brief description of the treatment was given to all patients and consent was signed from all participants. The final decision for treatment was decided by the team of senior surgeons as well as with help of the patient's own choice. Limberg flap and primary midline wound closure (PMC) were applied to patients who regularly followed the instruction for chronic pilonidal sinus treatment. Primary midline closure was applied on patients who had a cosmetic concern and did not have a recurrence problem. Results: Total 60 patients were divided into two groups, Group A (Limberg flap) had 30 patients in which 25 (83%) were males and 5 (16.6%) females. The mean age for this group was 25 ± 5.00 years. The patients without a previous history of pilonidal sinus disease (primary case) was 17 (56.6%) and the recurrence case was 13 (14.3%). Group B (primary midline wound closure) had 30 patients in which 18 (60%) were males and 12 (40%) females. The mean age for this group was 28 ± 3.00 years. The patient without a previous history of pilonidal sinus disease (primary case) was 28 (93.3%) and the recurrence case was 2 (6.6%). The comparison of 3rd-week outcomes shows that in group A 25 (83,3%) patients had painless walking, 23 (76.6%) patients start their routine work and 26 (86.6%) patients had treatment satisfaction. In group B 21 (70%) patients reported painless walking, 18 (60%) patients started their routine activity and 22 (73.3%) patients shows satisfaction with treatment. Conclusion: Hence we concluded that a better improvement percentage was measured high in group A (Limberg flap) than group B (PMC). Therefore limberg flap is better technique to treat the chronic pilonidal sinus disease. Keywords: chronic Pilonidal Sinus, primary midline wound closure (PMC), Limberg flap
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H. D., Hareesh, Thrishuli P. B. i Girish Kumar N. M. "Comparative study of delayed primary closure by shoelace technique versus conventional secondary suturing method in closure of fasciotomy wounds, done for spreading cellulitis with compartment syndrome". International Surgery Journal 7, nr 2 (27.01.2020): 471. http://dx.doi.org/10.18203/2349-2902.isj20200300.
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Background: Fasciotomy is a standard treatment for acute compartment syndrome. Historically, fasciotomy incisions were usually left open till oedema settles down. In literature, there is a wide range of wound closure techniques published, but none of them is deemed to be the best. In this study, focus is laid on whether delayed primary closure (DPC) by shoelace technique, is as effective as conventional secondary suturing, in closure of fasciotomy wounds, done for spreading cellulitis.Methods: All those patients who met below mentioned inclusion criteria and underwent fasciotomy, were allocated into 2 groups (A and B) where Group A consists of 30 patients undergoing conventional secondary suturing, whereas Group B consists of 30 patients undergoing DPC by shoelace technique for closure of fasciotomy wounds. Parameters such as duration of hospital stay, time taken for complete wound closure, local wound complications, hospital expenses, anaesthesia related complications between the two groups were compared.Results: Patients who underwent DPC for fasciotomy wound closure achieved wound closure ~7 days earlier with 5 days lesser hospital stay than that of those who underwent conventional secondary suturing. Average health care cost of Group B was significantly lower compared to Group A, but there was no statistically significant difference in incidence of wound infections between the two groups.Conclusions: DPC by shoelace technique, takes less time for wound closure and hence the need for nursing care and hospital stay is significantly reduced in comparison to the conventional secondary suturing method.
Rozprawy doktorskie na temat "CLOSITE 30 B"
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SHARMA, SUBHA. "STUDIES ON BIOACTIVE NANOCOMPOSITE SERICIN/PVA BLEND FILMS". Thesis, 2016. http://dspace.dtu.ac.in:8080/jspui/handle/repository/14623.
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The present study focuses on the preparation and characterization of bioactive nanocomposite sericin/ polyvinyl alcohol (PVA) blend films. Films were prepared by blending sericin and PVA by solvent casting method. Different blends were created by varying the concentrations of glutraldehyde (GA), glycerol as plasticizer, closite 30B as bioactive nanoclay and silver nitrate as antimicrobial bioactive material. Films were characterised for mechanical, structural, morphological, thermal, biodegradable and antimicrobial properties. Fourier Transform Infrared Spectroscopy (FTIR) of films revealed that GA chemically cross linked with sericin and PVA. Scanning electron microscopic (SEM) revealed that no phase separation in prepared films. These films show the antimicrobial activity against gram negative bacteria Neisseria. Such biodegradable blended films can be used for smart food packaging material.
Części książek na temat "CLOSITE 30 B"
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Taber, Douglass F. "The Fuwa Synthesis of Didemnaketal B". W Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0097.
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Didemnaketal B 3 may be an artifact of isolation, derived from didemnaketal C, in which one of the methyl esters is instead an ethylsulfonate. Nevertheless, it is B, not C, that is a potent inhibitor of HIV protease. Haruhiko Fuwa of Tohoku University has provided (Chem. Eur. J. 2014, 20, 1848) a detailed account of the synthesis of 3, including the necessary revision of the absolute configuration of seven of the stereogenic centers. A central feature of the modular synthesis of 3 was the cyclization of 1 to the thermodynamically most favorable diastereomer of the spiroketal 2. Three components were combined for the synthesis of 3. The upper sidechain was prepared from commercial citronellal 4. Reduction followed by protection and ozonolysis delivered the aldehyde 5, that was carried on to the alkyne 6. Hydroiodination using the method previously reported by the authors (OHL May 30, 2011) gave 7, that was oxidized to 8 and then to the ester 9. Lactone formation by ring-closing metathesis is difficult because of the substantial preference for the extended conformation of the ester. As illustrated by the conversion of 10 to 11, this can be overcome by complexation with a Lewis acid. Conjugate addition followed by phosphorylation completed the preparation of the enol phosphate 12. The third component of 3 was the lactone 15, prepared by deprotonation/kinetic protonation with 14 of 13. This was carried on to the sulfone 16, that was coupled with 17. Although the Julia–Kocienski reaction usually strongly favors the E alkene, in this case it was necessary to optimize both the base and the solvent. Sharpless asymmetric dihydroxylation followed by coupling with the enol phosphate 12 then completed the preparation of the diol 1. Addition of the ketene silyl acetal 18 to the aldehyde derived from 2 proceeded to give the undesired diastereomer 19. This was overcome by oxidation to the ketone followed by enantioselective reduction. The iodide 9 was added to the aldehyde 20 to give a 1.8:1 mixture of diastereomers, the major one of which was didemnaketal B 3. This full paper is worth reading in detail. The work reported underlines the importance of powerful protocols for carbon–carbon bond formation that maintain high diastereocontrol in stereochemically complex environments.
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Oriakhi, Christopher O. "Liquids and Solids". W Chemistry in Quantitative Language. Oxford University Press, 2009. http://dx.doi.org/10.1093/oso/9780195367997.003.0016.
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The atoms or molecules in a liquid have enough kinetic energy to partially overcome the forces of attraction between them. Therefore, they are in constant random motion (as in a gas) but they are still relatively close together. However, they are not as tightly packed, or as well ordered, as in a solid. There is not as much free space in a liquid as in a gas. The atoms or molecules may aggregate together to form chains or rings that readily move relative to one another; this gives a liquid its fluid (flow) properties. Liquids generally occur as compounds. For example, water, ethanol, and carbon tetrachloride are liquids at room temperature. However, a few elements are also liquids at room temperature: bromine, cesium, gallium, mercury, and rubidium. A liquid is characterized by the following physical properties: boiling point and freezing point, density, compressibility, surface tension, and viscosity. These properties of a liquid are greatly influenced by the strength of its intermolecular forces. In summary: • Liquids have definite volume but no definite shape. They take on the shape of their containers. • Liquids are characterized by low compressibility, low rigidity, and high density relative to gases. • Liquids diffuse through other liquids. • Liquids can vaporize into the space above them and produce a vapor pressure. Polar molecules possess an electric dipole moment, μ, defined as the product of the magnitude of the partial charges Q+ and Q− on the molecule and the distance r separating the charges. In mathematical terms, it is given by the equation: μ = Qr The unit for μ is debyes (D), and 1 D = 3.336×10−30 coulomb meter (C-m). No interatomic bonds are completely ionic. Knowing the dipole moment of a compound, though, lets us differentiate ionic from covalent bonds by calculating the percent ionic character for the bonds. The percent ionic character of a bond is found by comparing the measured dipole moment of the molecule of the type A−B with the calculated dipole moment for the 100% ionized compound A+B−.
Streszczenia konferencji na temat "CLOSITE 30 B"
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Papapetrou, Georghios Dorou, Chia Pei Chuen, Mohd Nur Adzizie Mahamad, Ros Aliza Md Rabi i Yong Han Seah. "FDP Simulation Studies for Green Fields Cluster Development in Less than 30 Days Utilizing Cloud Technologies". W ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/211415-ms.
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Abstract BD Cluster green fields development located offshore Sabah, Malaysia, consists of three multi-stacked turbidite fields, namely A, B and C, encompassing thick and thin bed sands. Due to the lack of existing infrastructure in close proximity, a wellhead platform (WHP) will be installed on top of Field A. Fields B and C will be developed with a respective 8 and 7km subsea tie back to this WHP. Gas will be exported from the WHP to Facility-1 situated 5km away, whereas oil from a single thin oil rim reservoir in Field A will be exported to Facility-2 50km away. The challenges faced by the Reservoir Engineering (RE) Team was delivering an extensive number of dynamic simulations while adhering to the Field Development Planning (FDP) submission deadline: 1) uncertainty analysis and probabilistic modelling for 9 models, 2) construction of coupled reservoir models 3) screening alternative oil and gas export routes, and 4) optimizing capex phasing by determining the optimum startup sequence of the fields. Delivering the FDP work on time with the limited software licenses and computing infrastructure available on-premise appeared to be a "bridge too far". The limitations were addressed by PETRONAS LiveFDP digital transformation initiative commenced in 2019, through deployment of digital cloud technologies and solutions with scalable High-Performance Computing (HPC) environment. A total of 9 geological models were delivered to REs for dynamic simulation studies. Probabilistic modelling was then employed to obtain the dynamic P10, P50 and P90 models for each field. The Reservoir Coupling facility and Extended Network option were used in the numerical simulator to couple the standalone models in order to honor the overall facility constraints and incorporate the pipeline effects. Utilizing the coupled network model, multiple studies including condensate banking, determining optimum field sequencing and export route scenario were performed. The FDP subsurface development simulation runs were completed within 1 month using HPC cloud solutions and workflows compared to 9 months if using on-premise infrastructure. It provided the necessary tools to allow the team: 1) accurately assess the impact of condensate banking on well productivity, 2) executed over 1200 cases for probabilistic modelling for the 9 models in 24 hours of simulation time, 3) reduced the number of wells derived from a previous study from 14 to 9 yielding a saving of ~US$115 million, 4) ~US$50 million savings as a result of capex phasing by optimizing the field start up sequence, and 5) US$130 million savings by establishing the lowest cost oil and gas export route scenario.
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Blanton, Paul S., i Allen C. Smith. "Response of Conventional Ring Closures of Drum Type Packages to Regulatory Drop Tests With Application to the 9974/9975 Package". W ASME 2002 Pressure Vessels and Piping Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/pvp2002-1617.
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DOT, DOE and NRC Type A and Type B radioactive material (RAM) transport packages routinely use industrial or military specification drums with conventional clamp ring closures as an overpack. Considerable testing has been performed on these type packages over the past 30 years. Observations from test data have resulted in various design changes and recommendations to the standard drum specification and use, enhancing the reliability of the overpack. Recently, performance of the 9975 conventional clamp ring closure design was questioned by the DOE Regulatory Authority. This paper highlights the observations of recent 9974 and 9975 package testing that led to redesign of the 9975, replacing the standard clamp ring closure with a bolted flange closure. In the course of this review and redesign effort, 18 package designs and approximately 100 Hypothetical Accident Condition (HAC) drops of various size and weight drum packages were evaluated. A trend was observed with respect to overpack lid failures for packages utilizing conventional ring closure. Based on this trend, a limit on the ratio of the internal weight to total package weight was identified, beyond which clamp ring closure failure may be expected.
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Mantha, S., L. Mongeau i T. Siegmund. "Dynamic Digital Image Correlation of a Dynamic Physical Model of the Vocal Folds". W ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-81457.
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An experimental study of the vibratory deformation of the human vocal folds was conducted. Experiments were performed using model vocal folds [1, 2], Fig. 1, made of silicone rubber implemented into an air supply system, Fig. 2. The material used to cast the model is an isotropic homogeneous material, [3] with a tangent modulus E=5 kPa at ε = 0, i.e. elastic properties similar to those of the human vocal fold cover [4]. The advantages of the use of model larynx systems over the use of excised larynges include easy accessibility to fundamental studies of the vocal fold vibration without invasive testing. Acoustic analysis of voice or electroglottography provide certain insight into voice production processes but optical techniques for the study of vocal fold vibrations have drawn considerable attention. Videoendoscopy, stroboscopy, high-speed photography, and kymography have shown to provide a visual impression of vocal fold dynamics but are limited in providing insight into the fundamental deformation processes of the vocal folds. Quantitative measures of deformation have been conducted through micro-suture techniques but are invasive and allows for measurements of only view image points. Laser triangulation is non-invasive but is limited to only one local measurement point. Here, digital image correlation technique with the software VIC 3D [5] is applied. For the experimental set-up see Fig. 2. The analysis consists of (1) stereo correlation to obtain in-plane displacements and (2) stereo triangulation step to obtain out-of-plane deformation. For the stereo correlation images of the object at two different stages of deformation are compared. A point in the image of the undeformed object is matched with the corresponding point in the deformed stage. “Subsets” of digital images are traced via their gray value distribution from the undeformed reference image to the deformed image. The uniqueness of the matching is enabled by the creation of a speckle pattern on the object’s surface. Here, a white pigment is mixed into the silicone rubber and subsequently black enamel paint is sprayed onto the superior surface of the vocal folds. The stereo triangulation requires two images of the object at each stage of deformation. These are obtained in a single CCD frame by placing a beam splitter in the optical axis between camera and object. These images provide a “left” and “right” view of the model larynx. Thus, the deformed shape of the vocal folds can be obtained. The method allows for noninvasive measurement of the full-field displacement fields. Images of the superior surface of the model larynx are obtained by the use of a high speed digital camera with a frame rate of 3000 frames per second allowing for more than 30 image frames for each vibration cycle. For the 3D digital image correlation analysis two images of the object are obtained for each time instance as a beam splitter is placed in the optical axis between the camera and the model larynx. Phonation frequencies and onset pressure are given in Fig. 3, showing that the model larynx behavior is close to actual physiological data. Figs 4(a) and (b) provide superior views of the model larynx at maximum glottal opening and at glottal closure, respectively. As one example of measured strain fields, Figs 5(a) and (b) depict the distributions of the transverse strain component, on the glottal surface in a contour plot on the deformed superior surface. The knowledge of the distribution of this strain component is relevant to the assessment of the impact of vocal fold collision on potential tissue damage. In the position of maximum opening the vocal folds are deformed by a combination of a bulging-type deformation and the opening movement. At this time instance, the transverse strains at the medial surface are found to be negative, an indication of Poisson’s deformation. During the closing stage, vocal folds collide and simultaneously a mode 3 vibration pattern emerges. Closure of the glottal opening is not complete and two incomplete closure areas are formed during the closure stage. These open areas are located at the anterior and posterior ends of the model larynx, see Fig. 4(b). The finding of this type of incomplete closure is agreement with both actual glottal measurements [6] and 3D finite element simulations of [7]. Transverse strains during that stage are now positive and considerably larger that during the opening stage. Finally, Fig. 6 depicts the time evolution of the out of plane displacements along the medial surface for the closing phase and Fig. 7 depicts the maximum values of the longitudinal strain (at the coronal section of the medial surface) in dependence of the flow rate. These examples of measurements indicate that the DIC method is promising for studies of vocal fold dynamics.
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Sobolev, Roman, Yuliya Frolova, Varuzhan Sarkisyan i Alla Kochetkova. "Study of the Oxidative Stability of Oleogels Structured with Beeswax Fractions". W 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/zbfu3245.
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Combining the beeswax fractions is an effective way of structuring edible oils. However, their effect on oleogel oxidative stability is still not studied. Thus, the study on the influence of beeswax and combinations of its fractions on the edible oleogels oxidation was the objective of this research.Four fractions of beeswax (A, B, C, D) were isolated using preparative flash-chromatography and characterized by TLC and HPLC-ELSD. Sunflower oil was used to prepare oleogels (at 90 °C for 30 minutes) with a 6% of gelator. The fatty acid composition was evaluated by GC. The samples were stored at 35°C for 20 days, monitoring the oxidation using: PV, AV, CDV, TOTOX, HS-SPME-GC-MS. The induction period was determined using the OXITEST reactor.We have shown that fraction A contained hydrocarbons ( >99%); B - monoesters ( >95%); C - wax esters ( >66%), alcohols ( >29%), and free fatty acids ( >4%); D - alcohols ( >49%), free fatty acids ( >40%) and wax esters ( >10%). Combinations of A+B, A+B+C, and A+B+D gelators were made using fractions in equal amounts. The fatty acid composition of freshly prepared oleogels and oil didn't differ (p >0.05). Sunflower oil had the best oxidative stability among all samples. The A+B-based oleogel had the highest oxidative stability among the oleogels. Hexanal is shown to be the main volatile organic compound formed during the oxidation of sunflower oil. The volatile compounds profile of the oleogels also included ketones, alcohols, and terpenes. Beeswax-based oleogel had the lowest induction period, which indicates the presence of prooxidant components. A close correlation was found between the oxidation rate of oleogels and the content of free fatty acids (r2=0.8195) in the gelator.This study shows that the use of beeswax fractions, compared to beeswax itself, results in fat-containing products with higher oxidation stability.
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Sterthaus, Jens, Viktor Ballheimer, Claus Bletzer, Konrad Linnemann, Marko Nehrig i Frank Wille. "Numerical Approach for Containment Assessment of Transport Packages Under Regulatory Thermal Test Conditions". W ASME 2014 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/pvp2014-28199.
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The requirements of the IAEA safety standards for Type B(U) packages include the thermal test as part of test sequences that represents accident conditions of transport. In comparison to mechanical tests, e.g., 9 m drop onto an unyielding target with short impact durations in a range of approximately 10 ms to 30 ms, the extended period of 30 min is defined in regulations for exposure of a package to a fire environment. Obviously, the required containment capability of the package has to be ensured not only after completing the test sequence but also over the course of the fire test scenario. Especially, deformations in the sealing area induced by the non-uniform thermal dilation of the package can affect the capability of the containment system. Consequently, thermo-mechanical analyses are required for the assessment. In this paper some aspects of finite element analysis (FEA) of transport packages with bolted closure systems under thermal loading are discussed. A generic FE model of a cask is applied to investigate the stress histories in the bolts, lid, and cask body as well as the deformations in the sealing area and the compression conditions of the gasket. Based on the parameter variations carried out, some recommendations in regard to modeling technique and results interpretation for such kind of analyses are finally given.
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Newman, James C., Justin W. Shaw, Balkrishna S. Annigeri i Brett M. Ziegler. "Fatigue and Crack Growth in 7050-T7451 Aluminum Alloy Under Constant- and Variable-Amplitude Loading". W ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-68502.
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The 7050 aluminum alloy is used in many aerospace structural applications. Previous studies have identified that fatigue cracks develop very rough crack-surface profiles, which cause very high crack-closure levels due to a combination of plasticity, roughness and debris. Previously, tests were conducted on compact, C(T), specimens to generate crack-growth data from threshold to near fracture over a wide range in stress ratios (R). New threshold testing methods, based on compression precracking, were used to generate the data in the near-threshold regime. The plasticity-induced crack-closure model, FASTRAN, was used to correlate the data over a wide range in stress ratios and crack-growth rates from threshold to near fracture. To account for the very high crack-closure levels, a very low constraint factor, like plane-stress conditions, had to be used in the model. In addition, the crack-opening loads were measured during these tests using a local strain-gage method to generate another ΔKeff-rate curve. These two curves differed only in the near-threshold regime. Herein, fatigue-crack-growth tests were conducted on C(T) specimens under spike overloads and simulated aircraft spectrum loading. Also, fatigue tests were conducted on single-edge-notch bend, SEN(B), specimens over a wide range in loading conditions (constant amplitude and three aircraft spectra). All specimens were machined from a single forged block of 7050-T7451. However, no residual stresses were measured in both the SEN(B) and C(T) specimens. Two European standard spectra were used, but modified to have only tension-tension loading. The purpose of this paper was to evaluate the two different effective stress-intensity factor curves for making crack-growth and fatigue-life predictions. Small-crack theory was used to make fatigue-life predictions using inclusion-particle sizes from the literature. Fatigue predictions on the SEN(B) specimens agreed fairly well (± 30%) using a 12-micrometer semi-circular initial flaw located at the semicircular-edge notch under all loading conditions, except the model was unconservative (factor of 3) on one of the severe aircraft spectra (Mini-TWIST+, Level 1). For the C(T) specimens subjected to single-spike overloads, the life-prediction code produced much more retardation than observed in the tests. However, the predicted crack-length-against-cycles under the Mini-Falstaff+ spectrum were only about 15% longer than the tests. The discrepancy under the single-spike overloads and the severe aircraft spectra was suspected to be caused by the low constraint factor and/or crack paths meandering around overload plastic zones. Ideally, a roughness-induced crack-closure model, in addition to the plasticity model, would be needed to obtain more reasonable results.
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Almomani, Abdulla Fawzi, Hazem Alhaj i Abdel-Hamid Ismail Mourad. "The Impact of Silicon Content on the Corrosion Resistance of Nickel-Molybdenum Alloy in High Concentration Sulfuric Acid Transport". W ASME 2021 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/pvp2021-62023.
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Abstract This failure case analysis highlights the impact of silicon content on the corrosion resistance of Ni-Mo alloy piping welding joints, known as Hastelloy B-2 (UNS N10665), in high concentration sulfuric acid (98 wt. % H2SO4) medium. A damaged piping weld joint is analyzed against an accelerated corrosion mechanism which was found to shorten the joints lifetime drastically. Superiority of B-2 alloys is largely attributed to the high concentration of molybdenum (26–30 wt. %) that gives its corrosion resistance to highly reducing acidic environments. However, certain deficiencies, such as short-range ordering (SRO) and intermediate phases formations (Ni4Mo transformation) in its metallurgical structure, in the as-welded conditions, was found to hinder its thermal stability. In this piping failure case analysis, close examination including optical assessment, X-ray fluorescence (XRF) spectrometry, and in-situ replication metallography were performed on a defected weld neck butt-fusion welding joint. XRF revealed a silicon content of almost four times (0.38% against 0.1%) the ASTM maximum requirements, which appears to have lowered the alloy’s thermal stability and increased its kinetics to rapid phase transformation (from α to β) along the grain boundaries. Extensive second phase precipitates were observed along the domain boundary interfaces in the microstructure, which is suggested to have resulted in Mo-depleted zones in the matrix. In this case analysis, the welding temperature (650–750°C) of NiMo alloys butt-joints along with the silicon content (0.1% to 0.3%) present were found as main contributors to the reduction of the welding corrosion resistance and hence to the shortening of the piping lifetime.
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Subramanian, S., P. Schani, E. Widener, P. Liston, J. Moss i V. Soorholtz. "A Selected Area Planar TEM (SAPTEM) Sample Preparation Procedure for Failure Analysis of Integrated Circuits". W ISTFA 1998. ASM International, 1998. http://dx.doi.org/10.31399/asm.cp.istfa1998p0131.
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Abstract A selected area planar TEM (SAPTEM) sample preparation technique for failure analysis of integrated circuits using a transmission electron microscope has been developed. The technique employs a combination of mechanical grinding, selective wet/dry chemical etching (if required) and a two step focused ion beam IIFIB) milling. The mechanical grinding steps include: (a) a backside grind to achieve a die thickness less than 30 µm, (b) the support half ring glue, and (c) a cross-section grind from one side to reach less than 35 pm to the failing site. A selective wet or dry chemical etch is applied before, between,, or after FIB thinning depending on the nature of problem and device components. The FIB milling steps involve: (is) a high ion current cross-sectional cut to reach as close as 5-8 µm to the area of interest (b) a final planar thinning with the ion beam parallel to the surface of the die. The plan view procedure offers unique geometric advantage over the cross-section method for failure analysis of problems that are limited to silicon or certain layers of the device. Iln the cross-sectional approach, a thin section (thickness less than 250 µm) of a device is available for failure analysis, whereas in the planar procedure a 20 µm2 area of any layer (thickness less than 250 µm) of the device is available. The above advantage has been successfully exploited to identify and solve the following prablems in fast static random access memories (FSRAM): (i) random gateoxide rupture that resulted in single bit failures, (ii) random dislocations from the buried contact trenching that caused single bit failures and general silicon defectivity (e.g. implant damage and spacer edge defects), and (iii) interracial reactions.
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EL-Bagory, Tarek M. A. A., Maher Y. A. Younan i Hossam E. M. Sallam. "Limit Load Determination and Material Characterization of Cracked Polyethylene Miter Pipe Bends". W ASME 2011 Pressure Vessels and Piping Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/pvp2011-57587.
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The quality of Natural Gas Piping Systems, NGPS, must be ensured against manufacturing defects. The main purpose of the present paper is to investigate the effect of loading mode and load angle (30°,45°, and 60°) on the limit load of miter pipe bends, MPB, under different crack depths a/W = 0 to 0.4 at a crosshead speed 500 mm/min. The geometry of cracked and un-cracked multi miter pipe bends are: pipe bend angle, α = 90°, pipe bend factor, h = 0.844, standard dimension ratio, SDR = 11, and three junctions, m = 3. The material of the investigated pipe is a high-density polyethylene, HDPE, which is commonly used in natural gas piping systems. The welds at the miter pipe junction are produced by butt-fusion welding. For all loading modes the limit load is obtained by the tangent intersection method, TI, from the load deflection curves produced by the specially designed and constructed testing machine at the laboratory. Tensile tests are conducted on specimens longitudinally extruded from the pipe with thickness, T = 10, 30 mm, at different crosshead speeds (5–500 mm/min), and different gauge lengths (G = 20, 25, and 50 mm) to determine the mechanical properties of welded and un-welded specimens. The fracture toughness is determined on the basis of elastic plastic fracture mechanics, EPFM. Curved three-point bend specimens, CTPB, are used. All specimens are provided with artificially pre-crack at the crack tip, a/W = 0.5. The effect of specimen thickness variation (B = 10, 15, 22.5, 30, 37.5, and 45mm) for welded and un-welded specimens is studied at room temperature (Ta = 23°C) and at different crosshead speeds, VC.H, ranging from 5 to 500 mm/min. The study reveals that increasing the crack depth leads to a decrease in the stiffness and limit load of MPB for both in-plane, and out-of-plane bending moment. In case of combined load (out-of-plane and in-plane opening; mode) higher load angles lead to an increase in the limit load. The highest limit load value occurs at a loading angle, φ = 60°. In case of combined load (out-of-plane and in-plane closing; mode) the limit load decreases with increasing load angles. On the other hand, higher limit load values are proved at a load angle, φ = 30°. For combined load opening case; higher values of limit load are obtained. The crosshead speed has a significant effect on the mechanical behavior of both welded and un-welded specimens. The fracture toughness, JIC, is greater for un-welded than welded specimen.
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Abdi, Frank, Saber DorMohammadi, Jalees Ahmad, Cody Godines, Gregory N. Morscher, Sung Choi, Rabih Mansour i Steve Gonczy. "Optimizing Ceramic Matrix Composite Interlaminar Fracture Toughness (Mode I) Wedge Test". W ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-58076.
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ASTM test standards for CMC’s Crack Growth Resistance (CGR) may exhibit a zig-zag (wavy) crack path pattern, and fiber bridging. The experimental parameters that may contribute to the difficulty can be summarized as: specimen width and thickness, interface coating thickness, mixed mode failure evolution, and interlaminar defects. Modes I crack growth resistances, GI were analytically determined at ambient temperature using wedge test, a modified double cantilever beam (DCB). Several Finite Element (FE) based Multi-scale modeling potential techniques were investigated: a) Multi-scale progressive failure analysis (MS-PFA); b) Virtual Crack Closure Technique (VCCT). Advantages and disadvantages of each were identified. The final modeling algorithm recommended was an integrated damage and fracture evolution methodology using combined MS-PFA and VCCT. The material tested in this study was a slurry-cast melt-infiltrated SiC/SiC composite with Tyranno ZMI fibers (Ube Industries, Kyoto, Japan) and a BN interphase. The fiber architecture consisted of eight plies of balanced 2-D woven five-harness satin. The total fiber volume fraction was about 30% with half of the fibers in the 0° direction and half in the 90° direction. All specimens had a nominal thickness of 4 mm. An alumina wedge with 18° head angle (2α) was used. In this method, a splitting force is created by inserting a vertically-moving wedge in a notch causing the arms to separate and forcing an interlaminar crack at the sharpest end of the notch The MS-PFA numerical model predicted the damage and fracture evolution and utilized the GENOA UMAT (User Material Subroutine) for Damage and FEM (Finite Element Model) stress intensity and LEFM (Linear elastic Fracture Model), Cohesive Model for Fracture. The analysis results (Fracture energy vs. crack length, Fracture energy vs. load, Fracture energy vs. crack opening displacement) matched the Mode I coupon tests and revealed the following key findings. Mode I-Wedge specimen exhibits: 1) failure mode is due to interlaminar tension (ILT) only in the interface section and a zig-zag pattern observed; 2) VCCT crack growth resistance is well matched to the test data; and 3) failure mode is a mixed mode behavior of Interlaminar tension (ILT) to interlaminar shear (ILS). The final Wedge test specimen configuration optimization includes the sensitivity of design parameters to CGR: a) wedge contact coefficient of friction; b) lever arms thickness, and c) inclined head angle, distance between the initial crack and wedge tip.