BackgroundFine needle aspiration cytology (FNAC) is the gold standard for detecting thyroid nodules. It is a costefficient approach that affords prompt and accurate evaluation. It is crucial in deciding to treat patients with suspected malignancy of thyroid nodules that might have thyroid surgery. According to findings in cytology, patients may be observed when the cytology is benign, and surgery can be performed if the cytology is malignant, which leads to a reduction in the incidence of unneeded surgery. AimThe current study aims to assess the concordance between FNAC of thyroid nodules with final histopathology and identify the different types of detected thyroid lesions. MethodologyA retrospective record-based study reviewed the medical files of all patients presenting to the Armed Forces Hospital, Southern region, with suspected thyroid nodules from April 2018 to January 2020. Data were extracted using pre-structured data extraction sheet to avoid inconsistency. Data extracted included patients' demographic data, swelling laterality, size, ultrasound, and histopathological findings. ResultsThe baseline characteristics of studied samples in the present study: Forty-seven samples had a mean age of 44.27 (SD=±13.5) years, and 85.1% were female gender. The study showed that 12.5% of benign samples were lymphocytic in histopathology, 25% suspicious for follicular neoplasm samples were benign multi-nodular goiter in histopathology, and all 100% of samples suspicious for malignancy were malignant in final histopathology. ConclusionsThe current study showed that the malignancy rate of the examined nodules was not uncommon in FNAC and histopathology. Where papillary carcinoma was the most detected malignancy, the diagnosis of malignancy using FNAC is a cost-efficient approach that affords prompt and accurate evaluation. Once diagnosed, these cases should be subjected to surgery.
Abstract-In high pressure laminar explosions, special behavior may exist called instability at negative Markstein numbers. This behavior will cause pressure oscillations and will have certain effects on burning velocities of the fuel mixture. Flame winkling begins to appear as a results of Darrieus-Landau, D-L, instabilities and thermal-diffusive effects at higher pecelt number (as critical value is exceeded). Consequently an increase of burning rate will take place. This increase is capable of creating a pressure waves strong enough, if aligned non-orthogonally to parts of the flame surface, which result in further wrinkling from the Taylor instability along with vorticity generation. In this work, an iso-octane mixtures were ignited at two diametrically opposite sparks close to the wall of the bomb at higher pressure in the later stages of combustion. An advantage of this technique is to allow for instabilities to take place and to view the two flames structures through a central window. More details about this method are found in [1]. This method was also applied to investigate instabilities effect on turbulent flames.Keyword-Hydrocarbon Fuel, Flames, Emissions, Combustion, Carbon Oxides. [5][6][7] that Laminar spherical flames can become unstable above a critical Peclet number (the flame radius, r, normalized by the flame thickness, δ l ). These instabilities become manifest as flame wrinkling over a range of wavelengths. As a results, the laminar burning velocity, will be influenced and hard to evaluate experimentally. High Peclet number, Pe can increase at high pressures, (as in engines) due to the smaller flame thickness values of, δ l . Also, it was found that as pressures increase the strain rate Markstein number, Ma sr decreases [5,6,8,9]. The associated instabilities with these flames cause a continually increasing burning velocity. This work reports a study for iso-octane -air explosion at an equivalence ratio, =1.6. The initial conditions were 0.5 MPa and 358 K. With the emphasis on unstable flames. The mentioned method above was advantageous in that Peclet numbers were maximized by large flame radii and small flame thicknesses I. INTRODUCTION It was shown from Theoretical studies [2-4] and experimental researches II.SPECIFIC OBJECTIVES The purpose of conducting this investigation is to study the structure of unstable flames, Bothe laminar and turbulent flames at high pressures and temperatures at late stages of combustion process where values of pressure, P, and temperature, T, will be high. These instabilities will start to develop when cells evolution start to appear on flame surface area and begin division. Also, the effects of such instabilities on the burning rates enhancement for laminar and turbulent spherical flames at certain conditions have been investigated. III.EXPERIMENTAL A 385.6 mm diameter spherical stainless steel bomb had three pairs of orthogonal windows of 150 mm diameter was used. The inside radius of the sphere, Ro , was 192.78 mm. The vessel and the used mixture (isooctane-...
The combustion process in hydrocarbon fuels, involves complicated chemical reactions associated with bond braking, radicals production and heat generation which are responsible for flames initiation. The conditions, such as pressure, temperature and mixture strength, make a strong influence on combustion. This paper reports an investigation of combustion characteristics of premixed propane/air flames and the effects of initial conditions on heat production rates, emissions (combustion products) and final equilibrium pressure and temperature values. Different mixtures concentrations were used in this study, including lean, stoichiometric and rich (φ = 0.8, 1.0, 1.2), subject to different pressures and temperatures ranging from 5-40 bars and 350-600 K, respectively. The elevated pressures and temperatures values were deliberately selected in this study to have more data available in the literature to fill in the gap in research and also to cover conditions that are similar to those in engines, in an attempt to have a better understanding on how to control emissions from these engines which is a major concern nowadays. Results show that rich mixture of propane fuel produces the highest rate for carbon monoxide (CO) with slight increase as pressure and temperature increase, where the stoichiometric mixture produces the highest rate of carbon dioxide (CO 2). It was noted that this type of emission decreases with the increase of pressure and temperature. On the other hand, nitric acid (NO) was found to be the highest for the lean mixture with sharp increase as pressure and temperature increase. Finally, the combustion heat (Q) is extracted from each mixture which plotted against pressure and it was also found that rich mixture of this fuel produces the highest and increases sharply with increased pressures and temperatures.
BackgroundThyroid nodules are well-defined regions of aberrant echogenicity within the thyroid parenchyma that are radiologically distinct from the normal thyroid gland. The most common incidental finding in imaging scans that include the neck is a thyroid nodule. Rarely are thyroid nodules cancerous, as the majority are benign. AimThe current study aims to assess the concordance between ultrasound (US) of thyroid nodules and final histopathology results to identify the different types of detected thyroid lesions. MethodologyA retrospective study reviewed the medical files of all patients presenting to the Armed Forces Hospital, Southern Region, with suspected thyroid nodules from April 2018 to January 2020. Data were extracted using pre-structured proforma to avoid inconsistency. Data extracted included patient demographic, swelling laterality, size, and US and histopathological findings. ResultsIn the present study, 47 samples had a mean age of 44.27 (SD = ±13.5) years, 85.1% were of the female gender, the majority (85.1%) had multiple nodules, 38.3% were with Thyroid Imaging Reporting and Data System (TI-RADS) TR4 US score, and the median size of the nodule on US was 3 cm with a range of 0.6 to 14 cm. The study showed that 10% of TR1 samples were lymphocytic in histopathology, 66.7% of TR3 samples were benign multinodular goiter in histopathology, and 55.6% of samples of TR4 were malignant in histopathology. ConclusionsThe current study showed that the malignancy rate of the examined nodules was not uncommon both by US and histopathology, where papillary carcinoma was the most detected malignancy. The study showed a satisfactory agreement rate between TI-RADS classification by US sonography and histopathological reporting, where TR4 and TR5 by the US were mainly categorized as pre-malignant/malignant lesions by histopathology.
An estimation of combustion products (pollutants) which include CO, CO 2 and NO mole fraction are reported in this paper for premixed methane/air flames. Different mixtures were used in this study, including lean, stoichiometric and rich subjected to varying degrees of pressures and temperatures ranging from 5 -40 bars and 350 -600 K, respectively. In this work, computer software was used to calculate the produced emissions species as well as the final (adiabatic) temperatures for each mixture. Results show that rich mixture of methane fuel produces the highest rate for carbon monoxide (CO) with slight increase as pressure and temperature increase. Where the stoichiometric mixture produces the highest rate of carbon dioxide (CO 2 ). Results showed that this type of emission decreases with the increase of pressure and temperature. On the other hand, nitric acid (NO) was found to be the highest for the lean mixture with sharp increase as pressure and temperature increase. Finally, the combustion heat (Q) for each mixture where plotted against pressure and it was found that the rich mixture of methane produced the highest rates. Results also showed that combustion heat increases sharply with increased pressures and temperatures.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.