Pulsed TEA CO2laser with an input energy density of 1.1 kJ/liter stabilized by a double preliminary discharge

1982 ◽  
Vol 12 (1) ◽  
pp. 92-93 ◽  
Author(s):  
Tho V Nguyen ◽  
Z Puzewicz
2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Liuliu Li ◽  
Fengqiang Gong

The elastic energy stored in deep rock in three-dimensional stress environment is the energy source of rockburst. To investigate the energy storage characteristics of deep rock under different confining pressures, a series of triaxial single-cyclic loading-unloading compression tests were conducted on red sandstone specimens under eight confining pressures. The input energy density, elastic energy density, and dissipative energy density of the specimen in axial, circumferential, and total directions can be obtained by the area diagram integration method. The results show that the input energy density in the axial direction accounts for the largest logarithmic proportion of the total input energy density, and the relationship between all energy density parameters and unloading level can be described by quadratic function. In the axial direction, there is a linear function relationship among elastic energy density, dissipative energy density, and input energy density. In the circumferential direction, there is a quadratic function relationship among elastic energy density, dissipative energy density, and input energy density. For the total energy density parameters of the rock specimen, the relationship among elastic energy density, dissipative energy density, and input energy density conforms to the quadratic function. According to the above correlation function, the elastic energy stored in deep rock under different confining pressures can be accurately obtained, which provides a foundation for studying the mechanism of rockburst under three-dimensional unloading from the energy perspective.


2013 ◽  
Vol 423-426 ◽  
pp. 833-836
Author(s):  
Zi Fu Li ◽  
Chun Yu Zhang ◽  
Liu Ju Qi ◽  
Xue Tong Sun

In this paper the effect of selective laser melting (SLM) input energy density on densification behavior and tensile strengths of commercially pure (CP) titanium was investigated. Fully dense and high strength SLM CP titanium has been obtained. A complex bone-compatible tetrakaidecahedron based porous structure has been successfully SLM-fabricated with optimized laser parameters.


2007 ◽  
Vol 551-552 ◽  
pp. 411-416 ◽  
Author(s):  
G. Wang ◽  
Kai Feng Zhang ◽  
Wen Bo Han ◽  
D.Z. Wu ◽  
C.W. Wang

The superplastic bulging capabilities of Ti-6Al-4V butt-welded plates with 0.8mm in thickness with high energy beam welding methods namely plasma arc welding (PAW), electron beam welding (EBW) and laser beam welding (LBW) are studied in virtue of superplastic bulging tests. Superplastic bulging tests are performed at the superplastic forming temperature 925°C under 1MPa gas pressure. The superplastic bulging capability is represented by the maximum relative bulging height h after fracture. Experimental results suggest that all of butt-welded plates with high energy beam welding methods possess good superplastic bulging capability. Among them, the maximum relative bulge height of LBW is the highest, that of EBW is slightly lower and that of PAW is the lowest. The higher the input energy density is, the bigger the bulge height will be. Furthermore their microstructure evolutions of various weld metals during superplastic bulging were systematically analyzed via metallographical tests. The relation between the microstructure of weld metal and its superplasticity is found. Metallographical analysis shows that the microstructure of Ti-6Al-4V weld metal with high energy beam welding methods is composed of fine acicular martensite. The higher the input energy density is, the finer the martensite structure will be. Upon heating, this martensite changes to a basketweave-like structure and upon bulging, the martensite structure have the trend of transforming to fine equiaxed grain. This can explained the reason why the Ti-6Al-4V butt-welded plates with high energy beam welding methods have excellent superplastic bulging capability.


2013 ◽  
Vol 711 ◽  
pp. 229-234 ◽  
Author(s):  
Tian Jiao Xiao ◽  
Yong Lun Song ◽  
Qiu Shi Hu ◽  
Chao Li

As to traditional single electrode free welding arc, changes about energy density of the ionizing region in the center of arc column is not obvious with current increases due to structural limitations. In this paper, we developed parallel multi-electrode arc discharge torch which is based on the mechanism of self-magnetic contraction effect in welding arc, the torch effectively improve energy density of ionization region in non-melting inert gas arc, which is proved by experiments, and we discussed, effect of the pulse input energy and pulse frequency to energy density of the arc with parallel multi-electrode torch. This study demonstrated the approach of improving the energy density of arc ionizing region by self-magnetic pinch effect is feasible.


Author(s):  
Douyan Wang ◽  
Takao Namihira ◽  
Sunao Katsuki ◽  
Hidenori Akiyama

AbstractNon-thermal plasma produced by pulsed power discharges in atmospheric pressure gases have been studied for the treatment of exhaust gases. In this paper, results are reported of short duration of tens of nanoseconds pulsed power applied to a mixture of nitric oxide (NO), nitrogen, oxygen, and water vapor, simulating flue gases to remove nitrogen oxide (NOx). The effects of the initial NO concentration and the pulsed repetition rate on the percentage of NO removal are reported. The results showed that all NO could be removed completely at different pulse repetition rates. NO removal ratio reached 100% at (3.2 ± 0.1) × 10


Symmetry ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 465
Author(s):  
Wei-yao Guo ◽  
Feng-hai Yu ◽  
Yue Qiu ◽  
Tong-bin Zhao ◽  
Yun-liang Tan

It is generally acknowledged that the failure of the layer-crack structure is closely related to rock bursts (a layer-crack structure means a coal or rock rib that is cut by fractures that are parallel or sub-parallel to the surface of the rib). Understanding the mechanical behavior of the layer-crack structure under cyclic loading is beneficial for rock burst mitigation. This study experimentally investigated the influence of the geometry of vertical fissure (i.e., width, length and number) on the mechanical properties of layer-crack rock specimens. The results show that the sensitivity of parameters with respect to the geometry of the fissure from strong to weak is the number, length and width. First, the peak stress under cyclic loading increases by approximately 7.82%–17.35%, thereby exerting an obvious strengthening effect. Second, the fissure geometry slightly affects the energy evolution of the layer-crack specimen, i.e., the input energy density, elastic energy density and dissipated energy density all gradually increase with the increase of the number of cycles. However, when approaching a specimen failure, the increasing rates from quick to slow are the dissipated energy, input energy and elastic energy. Third, the damage variable of the layer-crack specimen shows a concave increasing trend with the increase of the number of cycles. When the number of cycles is equal, the damage increases with the increase of the number of fissures, but it decreases with the increase of the fissure length. Fourth, AE events occur shortly before specimen failures, but rapidly increase near the specimen failures. The accumulated AE events that lead to specimen failures decrease with the increase in the number of fissures. These results can provide some basic data for the research of rock bursts related to the failures of layer-crack structures.


2020 ◽  
Vol 655 ◽  
pp. 185-198
Author(s):  
J Weil ◽  
WDP Duguid ◽  
F Juanes

Variation in the energy content of prey can drive the diet choice, growth and ultimate survival of consumers. In Pacific salmon species, obtaining sufficient energy for rapid growth during early marine residence is hypothesized to reduce the risk of size-selective mortality. In order to determine the energetic benefit of feeding choices for individuals, accurate estimates of energy density (ED) across prey groups are required. Frequently, a single species is assumed to be representative of a larger taxonomic group or related species. Further, single-point estimates are often assumed to be representative of a group across seasons, despite temporal variability. To test the validity of these practices, we sampled zooplankton prey of juvenile Chinook salmon to investigate fine-scale taxonomic and temporal differences in ED. Using a recently developed model to estimate the ED of organisms using percent ash-free dry weight, we compared energy content of several groups that are typically grouped together in growth studies. Decapod megalopae were more energy rich than zoeae and showed family-level variability in ED. Amphipods showed significant species-level variability in ED. Temporal differences were observed, but patterns were not consistent among groups. Bioenergetic model simulations showed that growth rate of juvenile Chinook salmon was almost identical when prey ED values were calculated on a fine scale or on a taxon-averaged coarse scale. However, single-species representative calculations of prey ED yielded highly variable output in growth depending on the representative species used. These results suggest that the latter approach may yield significantly biased results.


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