Production Of Tubes Research Articles

The Effect of Juniperus virginiana Essential Oil on Candida albicans Biofilm Formation

Candida albicans is one of the most important natural microbiotas in human. It is responsible for creating various types of candidiasis as opportunistic yeast. Biofilm formation is one of the pathogenic factors of Candida albicans that triggers infection from any surface on which it is formed. In this study, the effect of Juniperus virginiana essential oil (JVEO) on growth, germ tube production and biofilm formation against C. albicans ATCC 10231 was investigated. JVEO effectively inhibited C. albicans biofilm formation with a minimum inhibitory concentration (MBIC50) of <1250μg/ml. Moreover, it suppressed hyphal growth and germ tube and biofilm formation in that strain. Transcriptomic analysis carried out by qRT-PCR revealed that the expression of HWP1, ALS3 adhesion related genes and CPH1, CYR1, UME6, HGC1 and EED1 hypha formation and maintenance related genes were all suppressed by JVEO. Furthermore, in the cAMP-dependent protein kinase pathway, RAS1 was down regulated but EFG1 was not affected. These results suggest that JVEO may be a potential therapeutic treatment and control of Candida biofilm formation.

Non-conventional tube shapes for lifetime extend of solar external receivers

In this work, several novel tube shapes of solar tubular receivers that differ from the classical circular shape are analysed aiming to reduce the stresses of the receiver tubes, without penalizing its thermal efficiency. The analysis is performed using analytical thermal and mechanical models of the literature adapted for their use with non-circular tube shapes, verifying the assumptions made with FEM simulations due to the lack of experimental data available.Among the geometries studied, the results show that oval cross-section tubes improve the thermal efficiency of the receiver at the expense of increasing the stresses considerably. Ovoidal tubes show worse thermal and mechanical behaviour when the frontal part becomes peakier. Semicircle tubes reduce the stress by 10.9%, while keeping constant or even slightly improving the thermal performance. The last ones, increase the lifetime of the receiver and reduces the receiver costs if the manufacturing of the new geometries does no overpass 3.5 times the present price of production of the circular tubes. Therefore, the use of asymmetric cross-section tubes with low rear-front surface ratios, and smooth front surfaces can be considered a good alternative for substituting traditional circular cross-section tubes in central receivers.

A Statistical Approach in the Analysis of Geometrical Product Specification during the Cold Tube Drawing Process

Cold tube drawing provides higher accuracy compared to hot approaches. The process can be used to reduce the dimensions of tubes, and depending on the reduction size, the wall thickness of these may be subject to changes. In the process, any form of variability provoked by external factors is highly sensitive, given that the resulting tubes are often the final step in tube production. This paper focused on the evaluation of the influence of pre-tube factors on key variables after the drawing process, i.e., the final roundness, outer diameter, and wall thickness of the tubes. For these purposes, a factorial design with fixed factors was implemented. It was also a goal to investigate if the single-pass type of drawing would guarantee good statistical results potentially leading to significant time and financial reductions. The measurements were executed in the machine ZEISS CenterMax. The statistical analysis took place on Minitab 19. The results prove that most factors, and their interactions, significantly impacted the response variables, leading the authors to understand that a single-pass approach would not properly work under the conditions defined for the experimentation. These results also allow for reflection on the causes and necessary measures related to lubrication, technological heritage, and quality that would impact the results themselves.

Creative Strategies of Ural Pipe Companies: Between Technological Heroism and Memorialization

The paper investigates the development of concept of authenticity in industrial cities. The author analyzes the presentation strategies pursued by the key enterprises of the Ural tube industry, as embodied in material (urban planning and industrial complexes) and verbal (historical narrative) forms. For those plants established in the 1930–1940s, namely, Pervouralsk Novotrubny and Chelyabinsk Pipe Rolling Plants, the main strategy was technological heroism associated with unique projects and recent reindustrialization. In contrast to them, the Seversky Pipe Plant, which switched to the production of tube only in the 1960s, built a representation around historical continuity in relation to the “mining civilization” of the Urals by preserving the place of historical memory – the blast furnaces of the 19th century. The author concludes that the historical differences in the narratives about enterprises affect the practices of their positioning in the urban environment, and, consequently, the very concept of authenticity, which in turn is required for the successful formation of the experience economy.

Influence of the purity of water-oil emulsions on the degree of contamination of the surfaces of finned tubes of air coolers

The existing technologies for cleaning finned bimetallic tubes of air-cooling devices and methods for control the contamination of the surface of aluminum alloys are analyzed in order to identify the disadvantages of the cleaning methods used in the production of finned tubes. A quantitative rapid assessment of the finned surface cleaning is obtained. Keywords: finned surface, contamination, cleaning, alkaline solution, finned bimetallic pipes, air cooler, control. alex@bgutmo.ru

Development and Theoretical Justification of an Innovative Process for the Production of Seamless Bilayer Bimetallic Tubes 530, 550, 610, 630, 720, and 820 mm in Diameter with Various Combinations of Steels and Wall Thicknesses

Development and Theoretical Justification of an Innovative Process for the Production of Seamless Bilayer Bimetallic Tubes 530, 550, 610, 630, 720, and 820 mm in Diameter with Various Combinations of Steels and Wall Thicknesses

Effect of speed parameters of reduction on the resulting pipe profile accuracy

The problems associated with the deviation of the geometric parameters of hotdeformed seamless tubes, when they are obtained by continuous rolling on stretch reduction non-mandrel mills, are described. The study on the influence of the speed and deformation parameters of reduction on the accuracy of the obtained tube profile is carried out. The relationship between the value of the plastic tension coefficient and the stress-strain state of the tube billet during the reduction process was studied. The method of numerical simulation and practical assessment of the adequacy of the calculation was chosen as the research method. This method allows to make a deep analysis of the stressed and thermal state of the billet during processing, it also allows to determine the load parameters of tubes rolling and to visualize the results. A numerical model of the reduction process of the tube profile 93,17&times;12,45 mm made of steel grade TT309 is developed. As input parameters for numerical simulation, the settings of the current stretch reduction mill TPA 21/168 were taken. The range of reduction speed rates is taken in accordance with the rates used in the production of hot-deformed seamless tubes under the conditions of TPA 21/168. As a result of the study, the influence of the plastic tension coefficient on the intensity and distribution of the acting stresses in the deformation zones and in the space between stands is determined. The influence of the plastic tension coefficient on the accuracy of the obtained tube profile is determined. It is established that reduction modes with the coefficient of plastic tension in the range z = 0,55-0,65 contribute to the uniform distribution of stresses in the billet and to the increase of the accuracy of the tube profile.

A comparative study for production of germ tube in Candida albicans of various pulmonary samples, by different methods in a tertiary care hospital of south west Rajasthan

Background: Systemic candidiasis is associated with a high crude mortality rate, even with first line antifungal therapy. C. albicans is the predominant cause of invasive fungal diseases which is a serious public health issue. The main objective was to assess the reliability of different media for germ tube production in Candida albicans isolated from various clinically diagnosed pulmonary samples.Methods: All Candida isolates were identified and speciated by conventional methods such as Gram’s staining, germ tube test, chlamydospore formation on corn meal agar, sugar fermentation test, sugar assimilation test, and growth on Hi-chrome candida agar.Results: Out of 108 clinical isolates of Candida albicans, 5 different methods were used for germ tube production. Pooled human sera showed 93/108 (86.1%) was the most sensitive method wherein YEPD (yeast extract peptone dextrose) broth 91/108 (84.7%) was the reliable and easy method for detection of germ tube, followed by trypticase soy broth 81/108 (81.4%); peptone water 80/108 (74.7%) and 2% sucrose 71/108 (65.7%).Conclusions: YPED broth is found to be a better serum free substrate and subsequently for the presumptive differentiation of C. albicans from non-albicans candida (NAC), without the extensive time required for the preparation and testing of pooled human serum. Furthermore, this medium is commercially available, more stable, effective, and is not bio hazardous.

In-vitro cytokine production and nasopharyngeal microbiota composition in the early stage of COVID-19 infection.

BackgroundTo determine and compare nasopharyngeal microbiota (NM) composition, in vitro basal (Nil tube), provoked (Mitogen tube) production of cytokines at the early stage of COVID-19.MethodsThis cross-sectional study included 4 age and sex-matched study groups; group 1 (recovered COVID-19) (n = 26), group 2 (mild COVID-19) (n = 24), group 3 (severe COVID-19) (n = 25), and group 4 (healthy controls) (n = 25). The study parameters obtained from the COVID-19 (group 2, and 3) at the early phase of hospital admission.ResultsThe results from the reaserch deoicted that the Mean ± SD age was 53.09 ± 14.51 years. Some of the in vitro cytokines production was significantly different between the study groups. Some of the findinggs on cytokines depicted a significant differences between study groups were interleukin (IL)-1β Nil, IL-1β Mitogen, and their subtraction (i.e Mitogen-Nil). Regarding IL-10, and IL-17a levels, Mitogen, and Mitogen-Nil tube production levels were significantly different between the groups. Surprisingly, most of these measures were lowest in the severe COVID-19 patients’ group. Using discriminant analysis effect size (LEfSe), Taxa of NM with significant abundance was determined. About 20 taxa with an LDA score > 4 were identified as candidate biomarkers. Some of these taxa showed a significant correlation with IL-1β and IL-10 Mitogen and Mitogen- Nil levels (R > 0.3 or < -0.3, p < 0.05).ConclusionsThe findings of this perticular study regarting the early stage of COVID-19 showed that in vitro cytokines production, studies might be more useful than the ordinary cytokines' blood level measurement. Besides, the study identified some NM species that could be candidate biomarkers in managing this infection. However, further detailed studies are needed in these fields.

Treating Early Delayed Gastric Tube Emptying after Esophagectomy with Pneumatic Pyloric Dilation

Introduction: Endoscopic pneumatic pyloric balloon dilation is a treatment option for early postoperative delayed gastric tube emptying following esophageal resection. This study aimed to determine the safety and effectiveness of endoscopic balloon dilation. Methods: Between 2015 and 2018, patients with delayed gastric emptying 8–10 days after esophageal resection with gastric tube reconstruction due to esophageal carcinoma were considered for inclusion. Inclusion criteria were ≥1 of the following: nasogastric tube production ≥500 mL/24 h, ≥300 mL gastric retention, ≥50% gastric tube dilatation on X-ray, or nasogastric tube replacement. Patients were excluded on evidence of anastomotic leakage or reintervention. Success was defined as the ability to expand intake without needing to replace the nasogastric tube. Dilation was performed using a 30-mm Rigiflex balloon. Results: Fifteen patients underwent pyloric dilation, 12 according to the study protocol. Treatment was performed at a median of 12 days (IQR 9–15) postoperatively. Success was achieved in 58%. At 3 months, 8 patients progressed to exclusively oral intake. The remaining 4 patients had supplementary nightly enteral tube feeding. There were no adverse events. Conclusion: Endoscopic balloon dilation of the pylorus is a safe, feasible therapy for early postoperative delayed gastric emptying. With a success rate of 58%, a clinical trial is a necessary next step.

Fast Blob and Air Line Defects Detection for High Speed Glass Tube Production Lines.

During the production of pharmaceutical glass tubes, a machine-vision based inspection system can be utilized to perform the high-quality check required by the process. The necessity to improve detection accuracy, and increase production speed determines the need for fast solutions for defects detection. Solutions proposed in literature cannot be efficiently exploited due to specific factors that characterize the production process. In this work, we have derived an algorithm that does not change the detection quality compared to state-of-the-art proposals, but does determine a drastic reduction in the processing time. The algorithm utilizes an adaptive threshold based on the Sigma Rule to detect blobs, and applies a threshold to the variation of luminous intensity along a row to detect air lines. These solutions limit the detection effects due to the tube’s curvature, and rotation and vibration of the tube, which characterize glass tube production. The algorithm has been compared with state-of-the-art solutions. The results demonstrate that, with the algorithm proposed, the processing time of the detection phase is reduced by 86%, with an increase in throughput of 268%, achieving greater accuracy in detection. Performance is further improved by adopting Region of Interest reduction techniques. Moreover, we have developed a tuning procedure to determine the algorithm’s parameters in the production batch change. We assessed the performance of the algorithm in a real environment using the “certification” functionality of the machine. Furthermore, we observed that out of 1000 discarded tubes, nine should not have been discarded and a further seven should have been discarded.

Silver Nanoparticles Biosynthesized with Spruce Bark Extract-A Molecular Aggregate with Antifungal Activity against Candida Species.

Due to their high content of biomolecules, combined with silver’s well known antimicrobial potential, silver nanoparticles biosynthesized using spruce bark (AgNP SBEs) demonstrate antibacterial and antioxidant activity, making them a versatile option for developing new antimicrobial agents that might be used for medical treatment or as adjuvants for the classical agents. This study aims to analyze if silver nanoparticles (AgNPs) mediated by spruce bark extract (SBE) and silver salts (AgNP SBE Acetate, AgNP SBE Nitrate) presents antifungal activity against five different Candida spp., synergistic activity with fluconazole, and if they interact with some virulence factors of C. albicans. AgNP SBEs presented MICs (minimum inhibitory concentrations) for all the five tested Candida spp. AgNP SBEs inhibited the growth of C. parapsilosis, C. krusei, and C. guilliermondii, exerted synergistic activity with fluconazole for C. parapsilosis and C. guilliermondii, and inhibited biofilm production for C. albicans, C. auris, and C. guilliermondii. MICs of AgNP SBE Acetate significantly inhibited the production of germ tubes of C. albicans. The expression of C. albicans SAP2 gene was down-regulated by the short-time treatment with MICs of AgNP SBE Acetate, while ALS3 and HSP70 genes were up-regulated by the AgNPs MICs. These results emphasize the potential of using the AgNP SBEs as treatments/adjuvants options, not only against the redundant C. albicans but also for the non-albicans Candida species (which are not as frequently involved in human pathologies, but, sometimes, can be more aggressive).

In Vitro Antifungal Activity of Silver Nanoparticles Biosynthesized with Beech Bark Extract.

Biosynthesis is a green method for the synthesis of silver nanoparticles (AgNPs). This study aimed to assess the antifungal activity of two silver nanoparticle solutions, synthesized using beech bark extract (BBE) and acetate and nitrate silver salts (AgNP Acetate BBE and AgNP Nitrate BBE), their influence on biofilm production, their potential synergistic effects with fluconazole, on different Candida spp., and their influence on virulence factors of C. albicans (germ tube production, gene expression for ALS3, SAP2, HSP70). Both the AgNP BBEs presented different minimum inhibitory concentrations for all the studied Candida spp., but biofilm production was inhibited only for C. albicans and C. guilliermondii. The growth rates of all the studied Candida spp. were inhibited in the presence of both AgNP BBEs, except for C. auris. Synergistic activity was observed for C. parapsilosis and C. guilliermondii, for different combinations of fluconazole with both the AgNP BBEs. The germ tube production of C. albicans was slightly inhibited by the AgNP BBEs. Only AgNP Acetate BBE was able to down-regulate the expression of SAP2. Overall, we can conclude that, even if more studies are necessary, AgNPs synthesized with beech bark extract might be an interesting alternative to classic antifungal treatments.

Numerical Calculation About Influence of Crystallizer Structure on the Stress Evolution Process of Horizontal Continuous Casting of Copper Tubes

Abstract The horizontal continuous casting plays a key role in the production of inner grooved copper tubes. In order to improve the accuracy of the temperature field model of the copper tubes' horizontal continuous casting process, the model heat transfer coefficient was validated through temperature measurement experiment of graphite crystallizer. The finite element model of stress field evolution was established, based on considering the temperature and microstructure changes. It was found that tensile stress was generated in the outer layer of the casting billet and compressive stress was generated in the inner layer, when the casting billet entered the primary cooling zone. The paper investigated the mechanism of the liquid inlet number and shape on the microstructure and stress distribution after the casting billet was solidified. When the number of liquid inlets was 6, the ratio of the semimajor axis of ellipsoid to the short semiaxis was 3:2, and the backward tilt angle was 10 deg, the equivalent stress value of the casting billet was smaller, and the grains were dense and uniform. This paper promotes the research of horizontal continuous casting process and provides measurable reference for improving the quality of casting billet in the further.

Production of bacterial cellulose tubes for biomedical applications: Analysis of the effect of fermentation time on selected properties

Biosynthesis of bacterial cellulose (BC) in cylindrical oxygen permeable molds allows the production of hollow tubular structures of increasing interest for biomedical applications (artificial blood vessels, ureters, urethra, trachea, esophagus, etc.). In the current contribution a simple set-up is used to obtain BC tubes of predefined dimensions; and the effects of fermentation time on the water holding capacity, nanofibrils network architecture, specific surface area, chemical purity, thermal stability, mechanical properties, and cell adhesion, proliferation and migration of BC tubes are systematically analysed for the first time. The results reported highlight the role of culture time on key properties of the BC tubes produced, with significant differences arising from the denser and more compact fibril arrangements generated at longer fermentation intervals.

Online Cooling System and Improved Similar Self-adaptive Strategy for Hot-rolled Seamless Steel Tube

In conventional hot-rolled seamless steel tube production, the tube was air cooled to room temperature, and the enhancing of mechanical properties mainly depends on adding alloys elements and additional offline heat treatment. Control cooling was an effective method that can obviously enhance mechanical properties and widely used in hot-rolled strip and plate production lines. To realize control cooling process, an online control cooling equipment was introduced, which can implement the efficient and uniform cooling process for annular seamless tube. Meanwhile, the controller system was built to ensure online continuous cooling process quickly and stably. In order to guarantee precise temperature control, a temperature model based on energy balance and finite difference method was proposed. In addition, a self-adaptive strategy based on improved similar tube was obtained for temperature control, which builds the self-adaptive model combining constrained one pass clustering algorithm and kNN algorithm. Finally, the proposed online control cooling system and temperature model were applied in a PQF460 hot-rolled seamless steel tube production line, which greatly improved qualification rate whilst retaining a good control precision and stability.

ATI 690

Abstract ATI 690 is a nickel-chromium-iron alloy that is intended for the production of nuclear grade tube that meets the requirements outlined in ATI 690 Alloy TREX, ATI, 2012. This alloy exhibits excellent resistance to many corrosive aqueous media and high temperature atmospheres. In addition to its corrosion resistance, ATI 690 has high strength, good metallurgical stability, and favorable fabrication characteristics. This datasheet provides information on composition, physical properties, microstructure, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-771. Producer or source: ATI.

Study of the rollers geometry effects in rotary tube piercing and wear analyses of mandrel according to the finite element method

The rotary tube piercing (RTP) is the first process of making the seamless tube after producing the desired alloy ingot. There are several approaches to manufacture a seamless tube, but one of the most common types is RTP. This approach covers a wide range of processes that are categorized according to the number and shape of the rollers. On the other hand, each of these types has designed guides in the output and input of the piercing process. In this paper, a new design of the input guide for four types of rollers have been examined and simulated. Thus, four specimens including Diescher and Conical rollers were considered, with the different number of rollers. Results including torque, total force, mandrel wear, temperature distribution, and strain were extracted using FEM simulation. In order to the validation of simulation, the total force and oscillations of applied force within the process have been compared with the experimental results. The results obtained through this simulation, are more in line with the empirical results obtained from previous research. As well as, the FEM simulation confirmed the performance accuracy of the output and input guides of the RTP process. On the other hand, the results indicate that the three-roller Diescher type with 17° feed angle, has the most suitable arrangement for production of seamless tube.

Self-assembly of anthraquinone covalent organic frameworks as 1D superstructures for highly efficient CO2 electroreduction to CH4

The design of selective and efficient covalent organic frameworks (COFs) based electrocatalysts with tunable morphology for efficient CO2 reduction reaction (CO2RR) to CH4 is highly desirable. Here, two kinds of anthraquinone-based COFs (i.e., AAn-COF and OH-AAn-COF) with tunable 1D superstructures (e.g., nanofibers (NF) and hollow tubes (HT)) have been produced via Schiff-base condensation reaction. Interestingly, a rarely reported nanosheet-based self-template mechanism and a nanosheet-crimping mechanism have been demonstrated for the production of COF-based nanofibers and hollow tubes, respectively. Besides, the obtained COF-based superstructures can be post-modified with transition metals for efficient CO2RR. Specifically, AAn-COF-Cu (NF) and OH-AAn-COF-Cu (HT) exhibit superior faradaic-efficiency with CH4 (FECH4) of 77% (−128.1 mA cm−2, −0.9 V) and 61% (−99.5 mA cm−2, −1.0 V) in a flow-cell, respectively. Noteworthy, the achieved FECH4 of AAn-COF-Cu (NF) (77%) the is highest one among reported crystalline COFs. This work provides a general methodology in exploring morphology-controlled COFs for electrocatalytic CO2RR.

Analysis of the tube piercing process types in terms of final product properties

The rotary tube piercing (RTP) is the first process of making seamless tube after producing the desired alloy ingot. There are several ways to make a seamless tube, one of the most common being RTP. This approach covers a wide range of processes that are categorized according to the number and shape of the rollers. On the other hand, each of these types has designed guides in the output and input of the piercing process. In this article, a new design of input and output guide for all types of rollers have been examined and simulated. Thus, three specimens including Diescher and Conical rollers were considered with 3 and 2 numbers, respectively. Results including torque, total force, temperature distribution and strain were extracted using FEM simulation. The results obtained through simulation are more in line with the experimental results obtained from previous research. While showing the successful performance of the output and input guides of the RTP process, the results indicate that the 3-roller Diescher type RTP has the most suitable arrangement for seamless tube production.