Friction and Lubrication Effects in Open Die Impact Forging

1975 ◽  
Vol 97 (1) ◽  
pp. 14-17 ◽  
Author(s):  
C. E. Cruff ◽  
C. C. Reynolds
Keyword(s):  
Reduction Curve ◽  
Available Energy ◽  
Forging Force ◽  
Friction And Lubrication

A horizontal forging machine, Impacter, was used to determine coefficients of friction under different conditions of forging 1020 steel and 2014 T-4 aluminum. Short cylinders were open die forged with repeated blows and the reduction of height determined for one to eight blows. The area under a calculated forging force versus reduction curve was related to available energy in the impellers so that a theoretical reduction for each blow could be determined for different coefficients of friction.

On-the-Fly Determination of Active Region Centers in Adaptive-Partitioning QM/MM

2020 ◽  
Author(s):  
Zenghui Yang
Keyword(s):  
Quantum Mechanics ◽  
Active Region ◽  
Molecular Mechanics ◽  
Active Regions ◽  
Available Energy ◽  
Adaptive Partitioning ◽  
Different Levels

Quantum mechanics/molecular mechanics (QM/MM) methods partition the system into active and environmental regions and treat them with different levels of theory, achieving accuracy and efficiency at the same time. Adaptive-partitioning (AP) QM/MM methods allow on-the-fly changes to the QM/MM partitioning of the system. Many of the available energy-based AP-QM/MM methods partition the system according to distances to pre-chosen centers of active regions. For such AP-QM/MM methods, I develop an adaptive-center (AC) method that allows on-the-fly determination of the centers of active regions according to general geometrical or potential-related criteria, extending the range of application of energy-based AP-QM/MM methods to systems where active regions may occur or vanish during the simulation.

Development of Pure Sine Wave Inversion System with Inbuilt Charging and Display Mechanisms

2018 ◽  
Vol 3 (2) ◽  
pp. 1-6
Author(s):  
Raji A. Abimbola
Keyword(s):  
Energy Demand ◽  
Noise Pollution ◽  
Sine Wave ◽  
Maintenance Cost ◽  
Air Conditioner ◽  
Health It ◽  
Power Generator ◽  
Available Energy ◽  
Wave Inversion ◽  
Running Cost

In recent years, Nigeria’s power generation output from all the available energy sources such as coal, natural gas, and water, is far from the expected number required to meet the energy demand of her teeming populace. This culminates in long hours of power outages frequently experienced in many parts of the country. However, there appears to be no end in sight to the problem. Alternatively, few citizens who can afford generator have wittingly resulted to the use of this device to supply power. Generator set has unavoidable disadvantages of high maintenance or running cost, noise pollution, and release of dangerous gases that pose danger to human lives. Evidently, that solution is risky and inadequate. Power inverter is an alternative and better means of generating electricity with little or no maintenance cost, environment or eco- friendly and poses no risk to human health. It is in that connection that we develop in this work 2KVA sine wave inversion system which produces sinusoidal A.C. signal required in homes for lightning and powering electronic gadgets like television, radio, refrigerator, Air conditioner etc. It is an improvement over square wave and modified sine wave inversion systems that generate digital approximations of A.C. signal. An interesting but new addition is the use of LCD display, interfaced with PIC16F688 microcontroller for showing the design specifications of the inverter.

scholarly journals Energy-Constrained Design of Joint NOMA-Diversity Schemes with Imperfect Interference Cancellation

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4194
Author(s):  
Fulvio Babich ◽  
Giulia Buttazzoni ◽  
Francesca Vatta ◽  
Massimiliano Comisso
Keyword(s):  
Interference Cancellation ◽  
Energy Levels ◽  
Random Access ◽  
Actual Performance ◽  
Available Energy ◽  
Fifth Generation ◽  
Code Modulation ◽  
Energy Constrained ◽  
The Relationship ◽  
The Internet Of Things

This study proposes a set of novel random access protocols combining Packet Repetition (PR) schemes, such as Contention Resolution Diversity Slotted Aloha (CRDSA) and Irregular Repetition SA (IRSA), with Non Orthogonal Multiple Access (NOMA). Differently from previous NOMA/CRDSA and NOMA/IRSA proposals, this work analytically derives the energy levels considering two realistic elements: the residual interference due to imperfect Interference Cancellation (IC), and the presence of requirements on the power spent for the transmission. More precisely, the energy-limited scenario is based on the relationship between the average available energy and the selected code modulation pair, thus being of specific interest for the implementation of the Internet of Things (IoT) technology in forthcoming fifth-generation (5G) systems. Moreover, a theoretical model based on the density evolution method is developed and numerically validated by extensive simulations to evaluate the limiting throughput and to explore the actual performance of different NOMA/PR schemes in energy-constrained scenarios.

scholarly journals Noni fruit’s water spot appearance on the second day of harvest: a trade-off between resistance and energy

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Tian Wu ◽  
Danyan Hu ◽  
Qingfen Wang
Keyword(s):  
Statistical Analysis ◽  
Molecular Level ◽  
Morinda Citrifolia ◽  
Transcriptome Data ◽  
Trade Off ◽  
Kegg Pathways ◽  
Available Energy ◽  
Climacteric Fruit ◽  
The Relationship ◽  
Insight Into

Abstract Background Noni (Morinda citrifolia Linn.) is a tropical tree that bears climacteric fruit. Previous observations and research have shown that the second day (2 d) after harvest is the most important demarcation point when the fruit has the same appearance as the freshly picked fruit (0 d); however, they are beginning to become water spot appearance. We performed a conjoint analysis of metabolome and transcriptome data for noni fruit of 0 d and 2 d to reveal what happened to the fruit at the molecular level. Genes and metabolites were annotated to KEGG pathways and the co-annotated KEGG pathways were used as a statistical analysis. Results We found 25 pathways that were significantly altered at both metabolic and transcriptional levels, including a total of 285 differentially expressed genes (DEGs) and 11 differential metabolites through an integrative analysis of transcriptomics and metabolomics. The energy metabolism and pathways originating from phenylalanine were disturbed the most. The upregulated resistance metabolites and genes implied the increase of resistance and energy consumption in the postharvest noni fruit. Most genes involved in glycolysis were downregulated, further limiting the available energy. This lack of energy led noni fruit to water spot appearance, a prelude to softening. The metabolites and genes related to the resistance and energy interacted and restricted each other to keep noni fruit seemingly hard within two days after harvest, but actually the softening was already unstoppable. Conclusions This study provides a new insight into the relationship between the metabolites and genes of noni fruit, as well as a foundation for further clarification of the post-ripening mechanism in noni fruit.

Excellent comprehensive energy storage capabilities achieved in linear polymer composites via inserting acrylic rubber dielectric elastomers

2021 ◽  
Author(s):  
Jie Chen ◽  
Yifei Wang ◽  
Weixing Chen
Keyword(s):  
Energy Storage ◽  
Energy Density ◽  
Polymer Composites ◽  
Linear Polymer ◽  
Dielectric Elastomers ◽  
Organic Film ◽  
Available Energy ◽  
Multilayer Composites ◽  
Potential Applications

Multilayer composites have the potential applications in organic film capacitors due to their excellent dielectric and breakdown characteristic. However, poor efficiency (η) and limited available energy density (Ue) of the...

On the time scales and structure of Lagrangian intermittency in homogeneous isotropic turbulence

2019 ◽  
Vol 867 ◽  
pp. 438-481 ◽  
Author(s):  
R. Watteaux ◽  
G. Sardina ◽  
L. Brandt ◽  
D. Iudicone
Keyword(s):  
Time Scales ◽  
Isotropic Turbulence ◽  
Flow Characteristics ◽  
Residence Times ◽  
Particle Trajectories ◽  
Local Flow ◽  
Available Energy ◽  
Homogeneous And Isotropic Turbulence ◽  
History Of ◽  
Optimum Manner

We present a study of Lagrangian intermittency and its characteristic time scales. Using the concepts of flying and diving residence times above and below a given threshold in the magnitude of turbulence quantities, we infer the time spectra of the Lagrangian temporal fluctuations of dissipation, acceleration and enstrophy by means of a direct numerical simulation in homogeneous and isotropic turbulence. We then relate these time scales, first, to the presence of extreme events in turbulence and, second, to the local flow characteristics. Analyses confirm the existence in turbulent quantities of holes mirroring bursts, both of which are at the core of what constitutes Lagrangian intermittency. It is shown that holes are associated with quiescent laminar regions of the flow. Moreover, Lagrangian holes occur over few Kolmogorov time scales while Lagrangian bursts happen over longer periods scaling with the global decorrelation time scale, hence showing that loss of the history of the turbulence quantities along particle trajectories in turbulence is not continuous. Such a characteristic partially explains why current Lagrangian stochastic models fail at reproducing our results. More generally, the Lagrangian dataset of residence times shown here represents another manner for qualifying the accuracy of models. We also deliver a theoretical approximation of mean residence times, which highlights the importance of the correlation between turbulence quantities and their time derivatives in setting temporal statistics. Finally, whether in a hole or a burst, the straining structure along particle trajectories always evolves self-similarly (in a statistical sense) from shearless two-dimensional to shear bi-axial configurations. We speculate that this latter configuration represents the optimum manner to dissipate locally the available energy.

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