scholarly journals Effect of Flow State of Pure Aluminum and A380 Alloy on Porosity of High Pressure Die Castings

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4219
Author(s):  
Hanxue Cao ◽  
Chengcheng Wang ◽  
Junqi Che ◽  
Ziwei Luo ◽  
Luhan Wang ◽  
...  
Keyword(s):  
High Performance ◽  
Pure Aluminum ◽  
Injection Velocity ◽  
Flow State ◽  
Filling Process ◽  
Air Entrapment ◽  
A380 Alloy ◽  
Observation Position ◽  
The Difference ◽  
Die Castings

Air entrapment defects prevent the heat treatment from improving the mechanical properties of die castings, which limits the die casting of high-performance components. The flow pattern of the filling process is complicated and experimental analysis is difficult in thin-walled complex die castings. In this study, we constructed a shock absorption tower to observe in real-time the filling process of pure aluminum and A380 aluminum alloy at different fast injection speeds. The degree of breakup of pure aluminum was larger than that of A380 during the filling process, which caused the porosity of pure aluminum to be greater than that of the A380 at each observation position. Re-Oh diagrams explained the difference in porosity between the two metals. The porosity in different regions was closely related to the flow state of aluminum liquid. In addition to porosity measurements, we specifically analyzed the relationship between the porosity of the flowback zone, the final filling zone, and the near-tail zone of cylinder. At the same injection velocity, the porosity at flowback zone was greater than that at the final filling position, the porosity at final filling position was larger than that at the near-tail zone of cylinder, and the final filling position changed as the injection velocity changed.

scholarly journals The Mechanical Properties and Damage Evolution of UHPC Reinforced with Glass Fibers and High-Performance Polypropylene Fibers

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2455
Author(s):  
Jiayuan He ◽  
Weizhen Chen ◽  
Boshan Zhang ◽  
Jiangjiang Yu ◽  
Hang Liu
Keyword(s):  
Mechanical Properties ◽  
Glass Fiber ◽  
Damage Evolution ◽  
High Performance ◽  
High Performance Concrete ◽  
Glass Fibers ◽  
Ultra High Performance Concrete ◽  
Concrete Damaged Plasticity ◽  
The Difference ◽  
Experimental Values

Due to the sharp and corrosion-prone features of steel fibers, there is a demand for ultra-high-performance concrete (UHPC) reinforced with nonmetallic fibers. In this paper, glass fiber (GF) and the high-performance polypropylene (HPP) fiber were selected to prepare UHPC, and the effects of different fibers on the compressive, tensile and bending properties of UHPC were investigated, experimentally and numerically. Then, the damage evolution of UHPC was further studied numerically, adopting the concrete damaged plasticity (CDP) model. The difference between the simulation values and experimental values was within 5.0%, verifying the reliability of the numerical model. The results indicate that 2.0% fiber content in UHPC provides better mechanical properties. In addition, the glass fiber was more significant in strengthening the effect. Compared with HPP-UHPC, the compressive, tensile and flexural strength of GF-UHPC increased by about 20%, 30% and 40%, respectively. However, the flexural toughness indexes I5, I10 and I20 of HPP-UHPC were about 1.2, 2.0 and 3.8 times those of GF-UHPC, respectively, showing that the toughening effect of the HPP fiber is better.

scholarly journals A Modified KNN Algorithm for High-Performance Computing on FPGA of Real-Time m-QAM Demodulators

Electronics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 627
Author(s):  
David Marquez-Viloria ◽  
Luis Castano-Londono ◽  
Neil Guerrero-Gonzalez
Keyword(s):  
Real Time ◽  
High Performance ◽  
Interference Mitigation ◽  
Parallel Implementation ◽  
Computational Time ◽  
Successful Implementation ◽  
Interchannel Interference ◽  
The Difference ◽  
High Level ◽  
Performance Computing

A methodology for scalable and concurrent real-time implementation of highly recurrent algorithms is presented and experimentally validated using the AWS-FPGA. This paper presents a parallel implementation of a KNN algorithm focused on the m-QAM demodulators using high-level synthesis for fast prototyping, parameterization, and scalability of the design. The proposed design shows the successful implementation of the KNN algorithm for interchannel interference mitigation in a 3 × 16 Gbaud 16-QAM Nyquist WDM system. Additionally, we present a modified version of the KNN algorithm in which comparisons among data symbols are reduced by identifying the closest neighbor using the rule of the 8-connected clusters used for image processing. Real-time implementation of the modified KNN on a Xilinx Virtex UltraScale+ VU9P AWS-FPGA board was compared with the results obtained in previous work using the same data from the same experimental setup but offline DSP using Matlab. The results show that the difference is negligible below FEC limit. Additionally, the modified KNN shows a reduction of operations from 43 percent to 75 percent, depending on the symbol’s position in the constellation, achieving a reduction 47.25% reduction in total computational time for 100 K input symbols processed on 20 parallel cores compared to the KNN algorithm.

scholarly journals Fast Comparison of High-Precision Time Scales Using GNSS Receivers

2017 ◽  
Vol 2017 ◽  
pp. 1-4
Author(s):  
Vojtech Vigner ◽  
Jaroslav Roztocil
Keyword(s):  
Time Scales ◽  
Time Scale ◽  
High Performance ◽  
Data Format ◽  
Common View ◽  
Log Files ◽  
Gnss Receivers ◽  
Precision Time ◽  
The Common ◽  
The Difference

Comparison of high-performance time scales generated by atomic clocks in laboratories of time and frequency metrology is usually performed by means of the Common View method. Laboratories are equipped with specialized GNSS receivers which measure the difference between a local time scale and a time scale of the selected satellite. Every receiver generates log files in CGGTTS data format to record measured differences. In order to calculate time differences recorded by two receivers, it is necessary to obtain these logs from both receivers and process them. This paper deals with automation and speeding up of these processes.

Behavior of Unsteady Turbulent Starting Round Jets

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Neerav Abani ◽  
Jaal B. Ghandhi
Keyword(s):  
High Speed ◽  
Penetration Rate ◽  
Injection Rate ◽  
Injection Velocity ◽  
Time Varying ◽  
Velocity Change ◽  
Rate Of Penetration ◽  
Round Jets ◽  
The Difference ◽  
Sudden Decrease

Turbulent starting jets with time-varying injection velocities were investigated using high-speed schlieren imaging. Two solenoid-controlled injectors fed a common plenum upstream of an orifice; using different upstream pressures and actuation times, injection-rate profiles with a step increase or decrease in injection velocity were tested. The behavior of the jet was found to be different depending on the direction of the injection-velocity change. A step increase in injection velocity resulted in an increased rate of penetration relative to the steady-injection case, and a larger increase in injection velocity resulted in an earlier change in the tip-penetration rate. The step-increase data were found to be collapsed by scaling the time by a convective time scale based on the tip location at the time of the injection-velocity change and the difference in the injection velocities. A sudden decrease in injection velocity to zero was found to cause a deviation from the corresponding steady-pressure case at a time that was independent of the initial jet velocity, i.e., it was independent of the magnitude of the injection-velocity change. Two models for unsteady injection from the literature were tested and some deficiencies in the models were identified.

Evaluation of the Interference of Hemoglobin Variant J-Bangkok on Glycated Hemoglobin (HbA1c) Measurement by Five Different Methods

2017 ◽  
Vol 125 (10) ◽  
pp. 655-660
Author(s):  
Dong-Mei Wen ◽  
Sheng-Nan Xu ◽  
Wei-Jia Wang ◽  
Xiu-Ming Zhang ◽  
Ming-Huan Suo ◽  
...  
Keyword(s):  
High Performance ◽  
Glycated Hemoglobin ◽  
Clinical Laboratory ◽  
Hemoglobin Variant ◽  
Deming Regression ◽  
Significant Difference ◽  
The Difference ◽  
Immuno Assay ◽  
Hba1c Measurement ◽  
Significant Interference

Abstract Objective The interference of the hemoglobin variant (Hb J-Bangkok) was evaluated on 4 different glycated hemoglobin assays and compared with a reference immuno assay. Methods An overall test of coincidence of 2 least-squares linear regression lines was performed to determine whether the presence of Hb J-Bangkok caused a statistically significant difference in HbA1c results compared with a reference immuno assay. Statistical analysis was performed on the difference of the estimated average glucose calculated from HbA1c values and fasting plasma glucose in the Hb J-Bangkok variant group using the different detection systems. Deming regression analysis was used to determinate whether Hb J-Bangkok had a significant interference on HbA1c results using an HbA1c±10% relative bias at 6% and 9% HbA1c as evaluation limits. Results Turbidimetric inhibition immunoassay method, and enzymatic methods were not affected by Hb J-Bangkok. However, Hb J-Bangkok showed statistically significant interference to the two ion-exchange high-performance liquid chromatography methods. Conclusion When performing HbA1c tests, clinical laboratory personnel should identify the Hb variant and select the appropriate methods or use alternative indicators.

scholarly journals Quantitative Analysis of Fluorescence Detection Using a Smartphone Camera for a PCR Chip

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3917
Author(s):  
Jong-Dae Kim ◽  
Chan-Young Park ◽  
Yu-Seop Kim ◽  
Ji-Soo Hwang
Keyword(s):  
Quantitative Analysis ◽  
Fluorescence Detection ◽  
High Performance ◽  
Low Cost ◽  
Dna Amplification ◽  
Fluorescent Detection ◽  
Rt Pcr ◽  
Commercial System ◽  
Intensity Changes ◽  
The Difference

Most existing commercial real-time polymerase chain reaction (RT-PCR) instruments are bulky because they contain expensive fluorescent detection sensors or complex optical structures. In this paper, we propose an RT-PCR system using a camera module for smartphones that is an ultra small, high-performance and low-cost sensor for fluorescence detection. The proposed system provides stable DNA amplification. A quantitative analysis of fluorescence intensity changes shows the camera’s performance compared with that of commercial instruments. Changes in the performance between the experiments and the sets were also observed based on the threshold cycle values in a commercial RT-PCR system. The overall difference in the measured threshold cycles between the commercial system and the proposed camera was only 0.76 cycles, verifying the performance of the proposed system. The set calibration even reduced the difference to 0.41 cycles, which was less than the experimental variation in the commercial system, and there was no difference in performance.

Core-shell Cu@C@ZIF-8 composite: a high-performance electrode material for electrochemical sensing of nitrite with high selectivity and sensitivity

2021 ◽  
Author(s):  
Feng Gao ◽  
Xiaolong Tu ◽  
Yongfang Yu ◽  
Yansha Gao ◽  
Jin Zou ◽  
...  
Keyword(s):  
High Performance ◽  
High Selectivity ◽  
Limit Of Detection ◽  
Metal Organic Framework ◽  
High Sensitivity ◽  
Electrochemical Sensing ◽  
Core Shell ◽  
Zeolitic Imidazolate Framework ◽  
Sensing Platform ◽  
The Difference

Abstract Herein, an efficient electrochemical sensing platform is proposed for selective and sensitive detection of nitrite on the basis of Cu@C@Zeolitic imidazolate framework-8 (Cu@C@ZIF-8) heterostructure. Core-shell Cu@C@ZIF-8 composite was synthesized by pyrolysis of Cu-metal-organic framework@ZIF-8 (Cu-MOF@ZIF-8) in Ar atmosphere on account of the difference of thermal stability between Cu-MOF and ZIF-8. For the sensing system of Cu@C@ZIF-8, ZIF-8 with proper pore size allows nitrite diffuse through the shell, while big molecules cannot, which ensures high selectivity of the sensor. On the other hand, Cu@C as electrocatalyst promotes the oxidation of nitrite, thereby resulting high sensitivity of the sensor. Accordingly, the Cu@C@ZIF-8 based sensor presents excellent performance for nitrite detection, which achieves a wide linear response range of 0.1 µM to 300.0 µM, and a low limit of detection (LOD) of 0.033 µM. In addition, the Cu@C@ZIF-8 sensor possesses excellent stability and reproducibility, and was employed to quantify nitrite in sausage samples with recoveries of 95.45-104.80%.

scholarly journals A Review of the Challenge in Measuring Hemoglobin A1c

2009 ◽  
Vol 3 (3) ◽  
pp. 439-445 ◽  
Author(s):  
Cas Weykamp ◽  
W. Garry John ◽  
Andrea Mosca
Keyword(s):  
High Performance ◽  
Hemoglobin A1c ◽  
Consensus Statement ◽  
Clinical Chemistry ◽  
Metrological Traceability ◽  
International Diabetes Federation ◽  
The United States ◽  
Medical Laboratory ◽  
Patient Groups ◽  
The Difference

The attraction of the simple biochemical concept combined with a clinical requirement for a long-term marker of glycolic control in diabetes has made hemoglobin A1c (HbA1c) one of the most important assays undertaken in the medical laboratory. The diversity in the biochemistry of glycation, clinical requirements, and management demands has resulted in a broad range of methods being developed since HbA1c was described in the late 1960s. A range of analytic principles are used for the measurement of HbA1c. The charge difference between hemoglobin A0 and HbA1c has been widely utilized to separate these two fractions, most notably found these days in ion-exchange high-performance liquid chromatography systems; the difference in molecular structure (affinity chromatography and immunochemical methods) are becoming widely available. Different results found in different laboratories using a variety of HbA1c analyses resulted in the need for standardization, most notably in the United States, Japan, and Sweden. Designated comparison methods are now located in these three countries, but as they are arbitrarily chosen and have differences in specificity, results of these methods and the reference values and action limits of the methods differ and only harmonized HbA1c in specific geographic areas. A reference measurement system within the concept of metrological traceability is now globally accepted as the only valid analytic anchor. However, there is still discussion over the units to be reported. The consensus statement of the International Federation of Clinical Chemistry (IFCC), the American Diabetes Association, the International Diabetes Federation, and the European Association for the Study of Diabetes suggests reporting HbA1c in IFCC units (mmol/mol), National Glycohemoglobin Standardization Program units (%), and estimated average glucose (either in mg/dl or mmol/liter). The implementation of this consensus statement raised new questions, to be answered in a concerted action of clinicians, biochemists, external quality assessment organizers, patient groups, and manufacturers.

Differential intestinal deconjugation of taurine and glycine bile acid N-acyl amidates in rats

1992 ◽  
Vol 262 (2) ◽  
pp. G351-G358
Author(s):  
R. Zhang ◽  
S. Barnes ◽  
R. B. Diasio
Keyword(s):  
High Performance Liquid Chromatography ◽  
Small Intestine ◽  
Liquid Chromatography ◽  
Bile Acid ◽  
Chenodeoxycholic Acid ◽  
High Performance ◽  
Biliary Fistula ◽  
The Difference ◽  
The Stability ◽  
Rat Bile

Mechanisms responsible for the difference in the relative amounts of taurine- and glycine-conjugated bile acid N-acyl amidates (Tau/Gly ratio) are not fully understood. In the present study, the stability of taurine- and glycine-conjugated bile acid N-acyl amidates during intestinal transit and absorption was examined to investigate the contribution of intestinal deconjugation to the Tau/Gly ratio in rat bile. Radiolabeled chenodeoxycholic acid (CDC) and its N-acyl amidates with glycine (CDC-Gly) or taurine (CDC-Tau) were introduced into the lumen of the upper small intestine in the biliary fistula rats, and radioactive metabolites in bile, blood, urine, and tissues were identified and quantitated by high-performance liquid chromatography. Results indicated that 1) extensive deconjugation of CDC-Gly occurs during intestinal absorption; 2) CDC-Tau is recovered in bile largely intact; and 3) newly synthesized CDC-Tau and CDC-Gly are formed in a ratio of less than 2:1 after administration of [14C]-CDC. In summary, the present study demonstrates that resistance of taurine-conjugated bile acid N-acyl amidates to hydrolysis in the intestine, rather than a difference in synthesis of taurine- and glycine-conjugated N-acyl amidates in liver, may account for the high Tau/Gly ratio in rat bile.

The Transporting Mechanic of Slurry of Heavy Oil and Sand in Horizontal Wellbore

2012 ◽  
Vol 271-272 ◽  
pp. 641-644
Author(s):  
Deng Sheng Lei ◽  
Xiao Liang Huang ◽  
Chun Bi Xu
Keyword(s):  
Heavy Oil ◽  
Flow State ◽  
Conduit Flow ◽  
Drag Forces ◽  
Horizontal Wellbore ◽  
Sand Particles ◽  
The Difference

It is a special modality of solid-fluid conduit flow for the sand transporting procedure in wellbore. Under the action of heavy oil, because of the difference of the borehole location, the transporting mechanic of sand is not the same. For the vertical wellbore, sand particles are mainly dominated by the drag forces and carried out of the hole; however, for the horizontal wellbore, sand particles are under complex forces and show different flow state. In different flow state, the sand particles are controlled by different forces, the heavy oil’s sand transporting capacity is changed. This paper begins with the analysis of the stress of the sand particles, and deeply analyses the vertical and horizontal wellbore, the stress of sand particles in the heavy oil’s sand mixing flow procedure, and then study the heavy oil’s sand transporting capacity.

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