scholarly journals Investigation of joints from laser powder fusion processed and conventional material grades of 18MAR300 nickel maraging steel

2021 ◽  
Author(s):  
W. Tillmann ◽  
L. Wojarski ◽  
T. Henning
Keyword(s):  
Tensile Strength ◽  
Maraging Steel ◽  
Solid Material ◽  
High Volume ◽  
Heat Treatment Condition ◽  
Hybrid Joint ◽  
Hybrid Joints ◽  
Laser Systems ◽  
Conventional Material ◽  
The Individual

AbstractEven though the buildup rate of laser powder bed fusion processes (LPBF) has steadily increased in recent years by using more and more powerful laser systems, the production of large-volume parts is still extremely cost-intensive. Joining of an additively manufactured complex part to a high-volume part made of conventional material is a promising technology to enhance economics. Today, constructors have to select the most economical joining process with respect to the individual field of application. The aim of this research was to investigate the hybrid joint properties of LBPF and conventionally casted 18MAR300 nickel maraging steel depending on the manufacturing process and the heat treatment condition. Therefore, the microstructure and the strength of the hybrid joints manufactured by LPBF or vacuum brazing were examined and compared to solid material and joints of similar material. It was found that the vacuum-brazed hybrid joints using a 50.8-μm-thick AuNi18 foil provide a high tensile strength of 904 MPa which is sufficient for a broad field of application. Furthermore, the additively manufactured hybrid samples offered with 1998 MPa a tensile strength more than twice as high but showed a considerable impact of buildup failures to the strength in general.

scholarly journals DESIGN, OPTIMIZATION AND EVALUATION OF CETRIZINE DIHYDROCHLORIDE FAST DISSOLVING FILMS EMPLOYING STARCH TARTRATE–A NOVEL SUPERDISINTEGRANT

2019 ◽  
pp. 75-86
Author(s):  
R. SANTOSH KUMAR ◽  
ANNU KUMARI ◽  
B. KUSUMA LATHA ◽  
PRUDHVI RAJ
Keyword(s):  
Tensile Strength ◽  
Drug Dissolution ◽  
In Vitro Dissolution ◽  
Content Uniformity ◽  
Scanning Calorimetry ◽  
Disintegration Time ◽  
Folding Endurance ◽  
Contour Plots ◽  
The Individual

Objective: The aim of the current research is optimization, preparation and evaluation of starch tartrate (novel super disintegrant) and preparation of fast dissolving oral films of cetirizine dihydrochloride by employing starch tartrate. Methods: To check the drug excipient compatibility studies of the selected drug (Cetrizine dihydrochloride) and the prepared excipient i. e starch tartrate, different studies like FTIR (Fourier-transform infrared spectroscopy), DSC (Differential scanning calorimetry) and thin-layer chromatography (TLC) were carried out to find out whether there is any interaction between cetirizine dihydrochloride and starch tartrate. The solvent casting method was used for the preparation of fast dissolving films. The prepared films were then evaluated for thickness, folding endurance, content uniformity, tensile strength, percent elongation, in vitro disintegration time and in-vitro dissolution studies. Response surface plots and contour plots were also plotted to know the individual and combined effect of starch tartrate (A), croscarmellose sodium (B) and crospovidone (C) on disintegration time and drug dissolution efficiency in 10 min (dependent variables). Results: Films of all the formulations are of good quality, smooth and elegant by appearance. Drug content (100±5%), thickness (0.059 mm to 0.061 mm), the weight of films varies from 51.33 to 58.06 mg, folding endurance (52 to 67 times), tensile strength (10.25 to 12.08 N/mm2). Fast dissolving films were found to disintegrate between 34 to 69 sec. Percent dissolved in 5 min were found to be more in F1 formulation which confirms that starch tartrate was effective at 1%. Conclusion: From the research conducted, it was proved that starch tartrate can be used in the formulation of fast dissolving films of cetirizine dihydrochloride. The disintegration time of the films was increased with increase in concentration of super disintegrant.

scholarly journals Current practice and perceptions of safety protocols for the use of intraperitoneal chemotherapy in the operating room: results of the IP-OR international survey

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Daniel Clerc ◽  
Martin Hübner ◽  
K.R. Ashwin ◽  
S.P. Somashekhar ◽  
Beate Rau ◽  
...  
Keyword(s):  
Operating Room ◽  
Intraperitoneal Chemotherapy ◽  
Current Practice ◽  
High Volume ◽  
International Survey ◽  
Protection Measures ◽  
Team Members ◽  
Cleaning Staff ◽  
The Individual ◽  
Or Team

Abstract Objectives To assess the risk perception and the uptake of measures preventing environment-related risks in the operating room (OR) during hyperthermic intraperitoneal chemotherapy (HIPEC) and pressurized intraperitoneal aerosol chemotherapy (PIPAC). Methods A multicentric, international survey among OR teams in high-volume HIPEC and PIPAC centers: Surgeons (Surg), Scrub nurses (ScrubN), Anesthesiologists (Anest), Anesthesiology nurses (AnesthN), and OR Cleaning staff (CleanS). Scores extended from 0–10 (maximum). Results Ten centers in six countries participated in the study (response rate 100%). Two hundred and eleven responses from 68 Surg (32%), 49 ScrubN (23%), 45 Anest (21%), 31 AnesthN (15%), and 18 CleanS (9%) were gathered. Individual uptake of protection measures was 51.4%, similar among professions and between HIPEC and PIPAC. Perceived levels of protection were 7.57 vs. 7.17 for PIPAC and HIPEC, respectively (p<0.05), with Anesth scoring the lowest (6.81). Perceived contamination risk was 4.19 for HIPEC vs. 3.5 for PIPAC (p<0.01). Information level was lower for CleanS and Anesth for HIPEC and PIPAC procedures compared to all other responders (6.48 vs. 4.86, and 6.48 vs. 5.67, p<0.01). Willingness to obtain more information was 86%, the highest among CleanS (94%). Conclusions Experience with the current practice of safety protocols was similar during HIPEC and PIPAC. The individual uptake of protection measures was rather low. The safety perception was better for PIPAC, but the perceived level of protection remained relatively low. The willingness to obtain more information was high. Intensified, standardized training of all OR team members involved in HIPEC and PIPAC is meaningful.

Formabilities of C-Si-Al-Mn Transformation-Induced Plasticity-Aided Martensitic Sheet Steel

2016 ◽  
Vol 838-839 ◽  
pp. 546-551
Author(s):  
Junya Kobayashi ◽  
Yumenori Nakashima ◽  
Koh Ichi Sugimoto ◽  
Goroh Itoh
Keyword(s):  
Tensile Strength ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Lath Martensite ◽  
Sheet Steel ◽  
Void Formation ◽  
High Volume ◽  
Stress Concentrations ◽  
Transformation Induced Plasticity ◽  
Al Content

The substitution of Si with Al in 0.2%C-1.5%Si-1.25%Mn-0.2%Cr ultrahigh strength transformation-induced plasticity (TRIP)-aided martensitic (TM) sheet steel improves galvanization. The effect of Al content on the microstructure and formabilities of the TM steel was therefore investigated. Replacement of Si with Al maintained the high volume fraction of the retained austenite and the high stretch-formability and stretch-flangeability, whereas it decreased the tensile strength. Complex addition of Si and Al yielded the best formabilities with 1.5 GPa tensile strength grade. The superior formabilities of Si-Al bearing TM steel were attributed to the strain-induced transformation of the metastable retained austenite and the relatively soft lath-martensite structure matrix. The former leads to plastic relaxation of the localized stress concentrations, thus suppressing void formation.

scholarly journals Intra-individual physiological response of recreational runners to different training mesocycles: a randomized cross-over study

2020 ◽  
Vol 120 (12) ◽  
pp. 2705-2713
Author(s):  
Peter Düking ◽  
Hans-Christer Holmberg ◽  
Philipp Kunz ◽  
Robert Leppich ◽  
Billy Sperlich
Keyword(s):  
Interval Training ◽  
High Volume ◽  
Physiological Adaptation ◽  
Time To Exhaustion ◽  
High Intensity Interval Training ◽  
Recreational Runners ◽  
Uptake Velocity ◽  
And Performance ◽  
High Intensity Interval ◽  
The Individual

Abstract Purpose Pronounced differences in individual physiological adaptation may occur following various training mesocycles in runners. Here we aimed to assess the individual changes in performance and physiological adaptation of recreational runners performing mesocycles with different intensity, duration and frequency. Methods Employing a randomized cross-over design, the intra-individual physiological responses [i.e., peak ($${\dot{\text V}}{\text O}_{2 {\rm peak}}$$ V ˙ O 2 peak ) and submaximal ($${\dot{\text V}}{\text O}_{2 {\rm submax}}$$ V ˙ O 2 submax ) oxygen uptake, velocity at lactate thresholds (V2, V4)] and performance (time-to-exhaustion (TTE)) of 13 recreational runners who performed three 3-week sessions of high-intensity interval training (HIIT), high-volume low-intensity training (HVLIT) or more but shorter sessions of HVLIT (high-frequency training; HFT) were assessed. Results $${\dot{\text V}}{\text O}_{2 {\rm submax}}$$ V ˙ O 2 submax , V2, V4 and TTE were not altered by HIIT, HVLIT or HFT (p > 0.05). $${\dot{\text V}}{\text O}_{2 {\rm peak}}$$ V ˙ O 2 peak improved to the same extent following HVLIT (p = 0.045) and HFT (p = 0.02). The number of moderately negative responders was higher following HIIT (15.4%); and HFT (15.4%) than HVLIT (7.6%). The number of very positive responders was higher following HVLIT (38.5%) than HFT (23%) or HIIT (7.7%). 46% of the runners responded positively to two mesocycles, while 23% did not respond to any. Conclusion On a group level, none of the interventions altered $${\dot{\text V}}{\text O}_{2 {\rm submax}}$$ V ˙ O 2 submax , V2, V4 or TTE, while HVLIT and HFT improved $${\dot{\text V}}{\text O}_{2 {\rm peak}}$$ V ˙ O 2 peak . The mean adaptation index indicated similar numbers of positive, negative and non-responders to HIIT, HVLIT and HFT, but more very positive responders to HVLIT than HFT or HIIT. 46% responded positively to two mesocycles, while 23% did not respond to any. These findings indicate that the magnitude of responses to HIIT, HVLIT and HFT is highly individual and no pattern was apparent.

Estimation of Polymer Coating Scratch Tensile Strength by Nano-Indentation, Micro-Scratch Testing, and Finite Element Modeling

2005 ◽  
Author(s):  
Timothy C. Ovaert ◽  
B. R. Kim
Keyword(s):  
Finite Element ◽  
Tensile Strength ◽  
Layered Structure ◽  
Polymer Coating ◽  
Performance Testing ◽  
Indentation Load ◽  
Individual Layer ◽  
Plastic Properties ◽  
The Individual ◽  
Scratch Tests

In a previous paper, polymer coating viscoelastic/plastic properties were determined using nanoindentation and the finite element method. In this work, the individual layers, once characterized, were assembled into a multi-layered structure and subject to micro-scratch tests. These tests determined a critical scratch indentation load for the layered structure, as designated by the first appearance during scratching of visible surface layer tensile cracks. Scratch tests were carried out for three different conical scratch tip radii. The top-layer tensile strength of the layered structures was then estimated, utilizing the individual layer properties, the top layer friction coefficients, the micro-scratch test critical loads, and a finite element scratch model, for each scratch tip radius. The values of the top layer scratch tensile strengths were in good agreement for each of the three tip radii, as anticipated. The top-layer scratch tensile strengths may be utilized for further analysis and comparison of differences in gloss retention after gloss reduction experiments. The method may be used as a basis for coating selection, comparison, and performance testing in scratch-resistant polymer coating applications.

Effects of carbohydrate and branched-chain amino acid beverage ingestion during acute upper body resistance exercise on performance and postexercise hormone response

2018 ◽  
Vol 43 (5) ◽  
pp. 504-509 ◽  
Author(s):  
JohnEric W. Smith ◽  
Ben M. Krings ◽  
Brandon D. Shepherd ◽  
Hunter S. Waldman ◽  
Steven A. Basham ◽  
...  
Keyword(s):  
Resistance Exercise ◽  
High Volume ◽  
Upper Body ◽  
Double Blind ◽  
Body Resistance ◽  
Branched Chain ◽  
And Performance ◽  
The Individual ◽  
Double Blind Design ◽  
Experimental Trials

The purpose of this investigation was to examine the individual and combined effects of ingesting carbohydrates (CHO) and branched-chain amino acids (BCAA) during high-volume upper body resistance exercise (RE) on markers of catabolism and performance. Thirteen resistance-trained males completed 4 experimental trials with supplementation, ingesting beverages containing CHO, BCAA, CHO+BCAA, or placebo (PLA) in a randomized, double-blind design. The beverages were ingested in 118-mL servings 6 times during an ∼60-min RE session consisting of bench press, bent-over row, incline press, and close-grip row. Each RE was performed with 5 sets of repetitions at 65% 1-repetition maximum until volitional fatigue. Blood samples were collected at baseline, immediately postexercise, and 60 min postexercise to assess glucose and insulin. Cortisol was assessed immediately and at 60 min postexercise. No significant performance benefits were observed for any RE. CHO+BCAA (152.4 ± 71.4 ng/mL) resulted in the lowest cortisol levels, which was lower than BCAA and PLA (193.7 ± 88.5, 182.8 ± 67.5 ng/mL, p < 0.05), but not different from CHO (165 ± 76.5 ng/mL, p = 0.342). Postexercise insulin concentrations were significantly higher with CHO (4.79 ± 3.4 mU/L) compared with BCAA and PLA (3.7 ± 2.0, 3.5 ± 1.8 mU/L, p < 0.05), but not different from CHO+BCAA (4.3 ± 2.5 mU/L, p = 0.339). There was no treatment effect for glucose, but glucose significantly increased from baseline to immediately postexercise and significantly decreased at 60 min postexercise. Ingesting beverages containing CHO with or without BCAA during upper body resistance exercise may promote a more favorable postexercise less catabolic environment.

Experimental Study on Workability and Strength of Green High Performance Concrete with High Volume Fly Ash

2013 ◽  
Vol 859 ◽  
pp. 52-55 ◽  
Author(s):  
Yong Qiang Ma
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
High Performance ◽  
High Performance Concrete ◽  
High Volume ◽  
Ash Content ◽  
Splitting Tensile Strength ◽  
Binder Ratio ◽  
Water Binder Ratio

A great deal of experiments have been carried out in this study to reveal the effect of the water-binder ratio and fly ash content on the workability and strengths of GHPC (green high performance concrete). The workability of GHPC was evaluated by slump and slump flow. The strengths include compressive strength and splitting tensile strength. The results indicate that the increase of water-binder ratio can improve the workability of GHPC, however the strengths of GHPC were decreased with the increase of water-binder ratio. When the fly ash content is lower than 40%, the increase in fly ash content has positive effect on workability of GHPC, while the workability begins to decrease after the fly ash content is more than 40%. The addition of fly ash in GHPC has adverse effect on the strengths, and there is a tendency of decrease in the compressive strength and splitting tensile strength of GHPC with the increase of fly ash content.

Self-Healing Glass Fibres with Carbon Nanotube-Epoxy Nanocomposite Coating

2007 ◽  
Vol 334-335 ◽  
pp. 805-808 ◽  
Author(s):  
Naveed A. Siddiqui ◽  
Jang Kyo Kim ◽  
Farjaad Muzaffar ◽  
Arshad Munir
Keyword(s):  
Tensile Strength ◽  
Carbon Nanotube ◽  
Strength Distribution ◽  
Neat Epoxy ◽  
Self Healing ◽  
Stress Concentrations ◽  
Clear Trend ◽  
Epoxy Nanocomposite ◽  
Glass Fibres ◽  
The Individual

This paper reports a study based on a novel concept of ‘self-healing’ coatings applied onto the brittle fibre surface to reduce the stress concentrations and thus to improve the reinforcing efficiency in a composite. The individual E-glass fibres as well as rovings were coated with a carbon nanotube (CNT) reinforced epoxy composite. The tensile strengths were measured for the individual and bundle fibres, which were treated statistically to determine the Weibull parameters and thus to evaluate the notch sensitivity of the fibres with and without coating. The results indicate that the tensile strength of the individual fibre increased by 10% after coating with neat epoxy. Coating with epoxy nanocomposite containing 0.3wt% MWNT further improved the tensile strength. However, increasing the nanotube content was not necessarily beneficial due to the formation of nanotube agglomerates within the matrix. The tensile tests on fibre roving also showed a clear trend of beneficial effect of nanocomposite impregnation on tensile strength. The rovings impregnated with nanocomposite exhibited a more uniform strength distribution and higher strengths than those impregnated with neat epoxy. Changes in prevailing failure mechanisms influenced by the epoxy and nanocomposite coatings are identified.

Tensile Strength of Surface Treated PBO Fiber

2015 ◽  
Vol 815 ◽  
pp. 622-628 ◽  
Author(s):  
Gang Shi ◽  
Su Ju ◽  
Chun Fang Huang ◽  
Da Zhi Jiang ◽  
Jian Wei Zhang
Keyword(s):  
Tensile Strength ◽  
High Performance ◽  
Fiber Surface ◽  
Interface Energy ◽  
Plasma Modification ◽  
Interface Properties ◽  
Weibull Analysis ◽  
Combined Treatments ◽  
Pbo Fiber ◽  
The Individual

Poly p-phenylene benzobisoxazole (PBO) fiber is a kind of organic fiber with high performance, but the properties of the interface between PBO fiber and resin are poor, which limit its application in the field of composite materials. Therefore, the surface modification methods were employed to enhance the interface properties, which could damage the fiber. This article assessed the influence of plasma modification, γ-ray irradiation, coupling agent, acid treatment and combined treatments on the strength of PBO fiber filament, and investigated its tensile strength with Weibull analysis. Through observation of fiber surface by SEM，it can be found that some combined treatments caused less damage to PBO fiber compared to the individual treatments. This indicates that if combining the different treatments appropriately, the interface energy of PBO fiber will increase, with the excellent mechanical properties well retained

Microstructures and Tensile Properties of Maraging Steel Processed by Equal-Channel Angular Pressing

2010 ◽  
Vol 667-669 ◽  
pp. 421-426 ◽  
Author(s):  
M.X. Yang ◽  
Gang Yang ◽  
Zheng Dong Liu ◽  
Cun Yu Wang ◽  
C.X. Huang
Keyword(s):  
Tensile Strength ◽  
Tensile Properties ◽  
Maraging Steel ◽  
Equal Channel Angular Pressing ◽  
Room Temperature ◽  
Aging Treatment ◽  
Subsequent Aging ◽  
Microstructural Refinement ◽  
Angular Pressing ◽  
Narrow Bands

An 18Ni (C-250) maraging steel was successfully processed by equal channel angular pressing (ECAP) for a single pass at room temperature. Microstructural observations showed that the martensite laths of 18Ni maraging steel were elongated to more narrow bands with a width of 100-200 nm after ECAP deformation. After ageing treatment, many nano-sized precipitates distributed uniformly within the refined martensite lathes. In comparison with the tensile strength (1940 MPa) of general used steel (solution + aging treatment), the tensile strength of the sample processed by ECAP and subsequent aging treatment was enhanced for more than 100 MPa (above 2050 MPa). The enhancement of tensile properties was attributed to microstructural refinement and uniformly distributed nano-precipitates.

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