specimen length
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Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7144
Author(s):  
Anatoly M. Bragov ◽  
Andrey K. Lomunov ◽  
Leonid A. Igumnov ◽  
Aleksandr A. Belov ◽  
Victor A. Eremeyev

Dynamic tests of fine-grained fired dioxide-zirconia ceramics under compression under uniaxial stress conditions were carried out. The influence of the specimen length on the obtained strength and deformation properties of ceramics is investigated. The thickness of the specimen has a significant impact on the course of the obtained dynamic stress–strain diagrams: short specimens have a much more sloping area of active loading branch. The main contribution to the modulus of the load branch resulting from tests of brittle porous media is made by the geometry of the specimens and the porosity of the material. When choosing the length of specimens for dynamic tests, the optimal geometry of the tested specimens is preferable in accordance with the Davies–Hunter criterion, when the contributions of axial and radial inertia are mutually compensated, and the contribution of the effects of friction in the resulting diagram is minimal. When choosing the geometry of specimens of brittle porous media, the structure of the material should be taken into account so that the size of the specimen (both length and diameter) exceeds the size of the internal fractions of the material by at least five times.


Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6025
Author(s):  
Maria Dimitriadi ◽  
Aikaterini Petropoulou ◽  
Konstantinos Masouras ◽  
Maria Zafiropoulou ◽  
Spiros Zinelis ◽  
...  

To improve the self-curing capacity and interfacial strength with dentine of dual-cured composite materials, touch-cure activators have been introduced. The aim of the study was to evaluate the effect of these activators on the hardness and conversion of dual-cured resin composite core build-up restoratives. The materials tested were Clearfil DC Core Plus (CF) and Gradia Core (GC) with the corresponding adhesives Clearfil S3 Bond Plus (for CF) and G-Premio Bond/G-Premio DCA activator (for GC). Disk-shaped specimens (n = 6/group) were prepared for the following groups: dual-cured, self-cured and self-cured in contact with the adhesive activators at the bottom surface. After a 3-week storage period (dark/dry/37 °C) the Martens hardness (HM) and degree of conversion (DC%) were determined for the previously mentioned groups and the top surfaces of groups in contact with the adhesives. A statistical analysis was performed by a one-way ANOVA and Holm–Sidak test per material and a Pearson’s correlation analysis (HM vs. DC%) at an α = 0.05. The self-cured specimens resulted in significantly lower HM and DC% values from the dual-cured group, as expected. However, in the presence of the adhesives with touch-cure activators, the conversion of the self-cured groups showed insignificant differences in HM and DC% from the dual-cured in both composite materials. The improvements on the bottom composite surfaces in contact with the adhesives did not extend to the entire specimen length. Nevertheless, improved interfacial curing may improve interfacial durability.


2021 ◽  
Vol 108 (Supplement_7) ◽  
Author(s):  
Shahab Hajibande ◽  
Mohammed Barghash ◽  
Asaf Khan ◽  
Baqar Ali

Abstract Aims Evaluating predictive significance of tumour size in patients undergoing curative colorectal cancer surgery. Methods Patients undergoing curative surgery (77.6% Laparoscopic) for colorectal cancer by a single surgeon between January 2013 and January 2020 inclusive. Linear/binary logistic regression analyses were modelled to assess whether colonic or rectal tumour size could predict R0 resection, specimen length, length >120mm, number of harvested lymph nodes, >12 harvested lymph nodes, number of positive lymph nodes, lymphocytic infiltration, venous invasion, and overall survival. Results Total of 192 patients (124 colon and 68 rectal cancers) were eligible. In colon cancer patients, tumour size was independent predictor of the number of harvested lymph nodes (P < 0.001), the number of positive lymph nodes (P = 0.001), and lymphocytic infiltration (P = 0.009). It did not predict R0 resection (P = 0.563), specimen length (P = 0.111), specimen length >120mm (P = 0.186), >12 harvested lymph nodes (P = 0.145), venous invasion (P = 0.103), 5-year overall survival (P = 0.543). Independent predictor in rectal cancers was the number of harvested lymph nodes (P < 0.001), and the number of positive lymph nodes (P < 0.001). It did not predict R0 resection (P = 0.108), specimen length (P = 0.774), specimen length >120mm (P = 0.405), >12 harvested lymph nodes (P = 0.069), lymphocytic infiltration (P = 0.912), venous invasion (P = 0.105), and 5-year overall survival (P = 0.413). Conclusions Current study results suggest tumour size alone may not have a significant predictive value in terms of oncological or survival outcomes in patients undergoing curative surgery for cancer of colon or rectum.


Author(s):  
Anugra Fikri Azmi ◽  
◽  
Yohanes Yohanes ◽  
Ridwan Ridwan Abdurrahman ◽  
◽  
...  

This research aims to investigate male-female chamfer angle effect on forging pressure, specimen length and the maximum tensile strength in splicing 6061 aluminum material, which used the rotary friction welding process. This research employed the analytical method to determine the timing of forging pressure as an initial reference to conduct the experimental study for the specimens test. The specimens were tested by varying the male-female chamfer angle, namely 0°, 15°, 30°, 45°, 60°. The results test were obtained the longest application of forging pressure at the male-female chamfer angle of 60° and the fastest application of forging pressure at the male-female chamfer angle of 15°. The change in length of the specimen during the welding process for each variation of the male-female chamfer angle varies due to the friction time different. The largest change in length was at the male-female chamfer angle of 15° and the smallest change in length at the male-female chamfer angle of 60°. The maximum tensile strength was obtained at the variation of male-female chamfer angle of 60° with a value of 226.47 MPa.


2021 ◽  
Author(s):  
Jueren Xie

Abstract Premium connection designs are typically evaluated and qualified to broadly adopted industry standards, such as ISO 13679 (2019) and API RP 5C5 (2017) procedures for testing casing and tubing connection in High Pressure and High Temperature (HPHT) wells up to temperatures of 180°C, and ISO/PAS 12835 (2013) for testing casing connection in thermal wells that experience temperatures from 180°C to 350°C. The primary focus of these qualification protocols is to evaluate the sealing capacity and structural integrity of the candidate connection design under loads representative of the conditions that the connection will experience through the well's life cycle. The test specimens consist of the coupling and the pipe segments on both sides of the coupling. While it may be desirable to evaluate test specimens with lengths equal to that of the field product to capture the temperature, pressure and mechanical loads on the specimen, it is advantageous to limit the length for purposes including handling and controlling the size and cost of the evaluation program. It has been observed that the test results can be affected by the specimen length, so the proper selection of specimen length is a key aspect of these evaluation programs. Current test protocols provide the requirement of a minimum unsupported length for allowing the tests to simulate the strain localization condition. On the other hand, if the unsupported length exceeds a critical value, the test specimens may experience lateral buckling, and preventing buckling adds complexity and cost to the test program. No guidelines have been given in the protocols on the maximum pup length requirement for preventing lateral buckling. Therefore, a better understanding of the impact of specimen length is warranted in order to achieve more reliable and accurate results from the testing program. This paper presents an investigation of the effect of specimen length on the structural integrity and sealability of premium connections based on Finite Element Analysis (FEA). Parametric FEA was completed to determine the impact of specimen length for several sizes of a generic premium connection design under API RP 5C5 (2017) HPHT well and ISO/PAS 12835 (2013) thermal well conditions. Based on the analysis results, recommendations are made to improve and enhance the guidelines for identifying a suitable specimen length for the test component of an evaluation program.


2020 ◽  
Vol 08 (07) ◽  
pp. E938-E943 ◽  
Author(s):  
Jose Nieto ◽  
Enad Dawod ◽  
Ameya Deshmukh ◽  
Eli Penn ◽  
Douglas Adler ◽  
...  

Abstract Background and study aims We compared the diagnostic yield and specimen adequacy in EUS-guided parenchymal biopsies between two types of EUS 19 G core needles. Patients and methods This is a retrospective study of 420 patients at two tertiary medical centers in Florida with unexplained abnormal liver associated tests were referred for EUS evaluation of biliary obstruction and pancreatic pathology. EUS-guided liver biopsy (EUS-LB) was performed at the same session after biliary obstruction was excluded. We compared intact specimen length (ISL), total specimen length (TSL), complete portal triads (CPT) and adverse events (AE). Welch’s T and Tukey tests were used for ISL, TSL and CPT. Results A total of 210 patients underwent EUS-LB using a Franseen needle, 210 patients using a fork-tip needle. Median patient age was 52 years (15.63) and 238 (56.7 %) were female. The fork-tip needle had a mean ISL of 2.7 (1.1 SD) cm, TSL of 6 cm (2.1 SD), and mean 19.5 CPT (8.5 SD) Abdominal pain occurred in 35 patients (17 %) post-procedure and was managed with supportive care. Two patients required intravenous (IV) narcotic administration. Subcapsular hematomas occurred in 1 (0.5 %) patients. The Franseen needle had a mean ISL of 3.1 cm (1.3 SD), TSL of 6.5 cm (2.6 SD), and mean of 24 CPT (8.8 SD). Abdominal pain occurred in four patients (2 %) post-procedure, which resolved in all patients after IV narcotic administration. Subcapsular hematomas occurred in 1 (0.5 %) and bile leak in 1(0.4 %) patients. Conclusions Use of the Franseen needle resulted in better liver core samples than that obtained with a fork-tip needle.


2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 690.1-690
Author(s):  
F. Muratore ◽  
L. Boiardi ◽  
A. Cavazza ◽  
T. Giacomo ◽  
R. Aldigeri ◽  
...  

Background:Temporal artery biopsy (TAB) showing inflammation is considered the gold standard for the diagnosis of giant cell arteritis (GCA). However, sampling error may lead to a negative TAB, and a negative TAB does not rule out GCA. The diagnostic sensitivity of TAB can be affected by the discontinuous character of the histopathologic changes (skip lesions) and by the length of specimens. The optimal TAB length and the optimal number of sections that need to be evaluated in order to avoid missing skip lesions are controversial.Objectives:To investigate the association between specimen length and number of section and the diagnostic yield of TAB for GCA.Methods:A pathologist with expertise in vasculitis and blinded to clinical data and final diagnosis reviewed all TABs performed for suspected GCA at our hospital between January 1991 and December 2012. The biopsies were routinely fixed in formalin and completely embedded in paraffin. Sections of 4 microns thickness were cut from paraffin blocks and stained with hematoxylin-eosin. TABs were classified into three categories: inadequate, when the biopsy did not sample the muscular artery; negative when the temporal artery was devoid of inflammation and positive when the temporal artery showed inflammation, arbitrarily defined as at least 1 aggregate of at least 15 inflammatory cells. The blocks of all the inadequate and negative biopsies were recut, and at least three further slides at deeper levels were stained with hematoxylin-eosin.Results:694 TABs were performed in the study period and were reviewed. 32 (4.6%) were classified as inadequate and were excluded from the analysis. Of the remaining 662 TABs [71% female; mean (SD) age, 73.2 (8.8) years], mean (SD) post fixation length was 6.63 (4.42) mm, and median number of sections evaluated was 3 (range 1-33). 382 (58%) TABs were classified as negative and 280 (42%) as positive. Compared with negative TAB, patients with positive TAB were older [mean age (SD) 74 (7.5) years vs 72 (9.6), p=0.009] and there was a trend for female predominance (75% vs 68%, p=0.077). Post fixation length of the specimens was significantly lower in negative compared with positive TAB [mean (SD) 6.37 (4.26) mm vs 6.99 (4.61) respectively, p=0.026]. Piecewise logistic regression identified 5 mm as the TAB length change point for diagnostic sensitivity. Compared with TAB length of <5 mm, age- and sex-adjusted odds ratio for positive TAB in samples ≥5 mm long were 1.536 (95% confidence interval, 1.108 to 2.130).The median (IQR) number of sections evaluated were 2 (1-3) for positive TAB and 4 (2-5) for negative TAB, p<0.0001. In 26/280 (9.3%) positive TABs, the first section was negative, and the inflammation was detected only in deeper sections (the positive section was the second in 14 TABs, the third in 9 and the fourth in 3). In all 26 cases, inflammation detected in deeper section was not transmural, but limited to adventitial or periadventitial small vessels.Conclusion:Our data confirm that a post fixation TAB length of at least 5 mm should be sufficient to make a histological diagnosis of inflamed temporal artery. According to our data, in order to avoid missing skip inflammatory lesions, at least 3 further sections at deeper levels should be cut and evaluated in all negative TABs.Disclosure of Interests:None declared


2020 ◽  
Vol 158 (3) ◽  
pp. S90-S91
Author(s):  
Trevor Wood ◽  
Karen Zaghiyan ◽  
Phil Fleshner

2020 ◽  
Vol 26 (Supplement_1) ◽  
pp. S56-S56
Author(s):  
Trevor Wood ◽  
Karen Zaghiyan ◽  
Phil Fleshner

Abstract Introduction Despite advances in medical management, including the use of biologic agents, up to 80% of Crohn’s patients (CD) ultimately require operative intervention. Additionally, these patients are at risk for additional operative intervention within their lifetime. Given the risk of short bowel syndrome secondary to multiple bowel resections, conservation of bowel length is of paramount importance. A common yet unproven belief in the gastroenterology community is that intensive preoperative medical therapy might reduce the length of bowel removed at surgery. In this study, we compared specimen length in CD patients treated or not treated with biologic agents before surgery. Objective To determine if there is an association between biologic use and reduced specimen length after bowel resection. Methods Prospectively generated clinical profiles on consecutive CD patients undergoing their first ileocolic or small bowel resection between November 1999 to July 2019 were reviewed. Patients were classified into 2 groups: Group A patients were treated with biologic agents at any time before surgery while Group B patients had never received a biologic agent. Specimen length was determined by review of pathology reports. In patients with multi-segment resections, the sum of the specimens was recorded. The means of the two groups were compared using Students t test. Results The study cohort of 392 patients had a mean age of 36.2 (SD 15.9) years and included 53% males. Group A included 247 (63%) patients and Group B included 145 (37%) patients. Groups were comparable in terms of background demographics with the exception of age, use of preoperative immunomodulator therapy, and medical intractability as an indication for surgery (p value 0.01, &lt;0.01, 0.02 respectively) The mean specimen length in Group A was 29.1cm compared to 29.9cm in the Group B (p=0.68). A subgroup analysis of ileocolic resections and small bowel resections was completed. Within the ileocolic group, there was no significant difference in length between groups with respect to the total specimen length (p=0.92), colonic portion (p=0.15), and small bowel portion (p=0.67). Analysis of small bowel resection specimens also found no difference in length between the groups (p=0.63). Conclusions The use of biologics in CD was not associated with reduced specimen length in ileocolic resections and in small bowel resections


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