Design of a Novel Quantitative Powder Feeding Apparatus

2021 ◽  
Vol 45 (8) ◽  
pp. 657-666
Author(s):  
Yu-Ting Wu ◽  
Zhen Qin ◽  
Yunseung Lee ◽  
Sungki Lyu ◽  
Seoungho Back ◽  
...  
2020 ◽  
pp. 1-15
Author(s):  
Zhiwei Yuan ◽  
Wen Guo ◽  
Dan Lyu ◽  
Yuanlin Sun

Abstract The filter-feeding organ of some extinct brachiopods is supported by a skeletal apparatus called the brachidium. Although relatively well studied in Atrypida and Athyridida, the brachidial morphology is usually neglected in Spiriferida. To investigate the variations of brachidial morphology in Spiriferida, 65 species belonging to eight superfamilies were analyzed. Based on the presence/absence of the jugal processes and normal/modified primary lamellae of the spiralia, four types of brachidium are recognized. Type-I (with jugal processes) and Type-II (without jugal processes), both having normal primary lamellae, could give rise to each other by losing/re-evolving the jugal processes. Type-III, without jugal processes, originated from Type-II through evolution of the modified lateral-convex primary lamellae, and it subsequently gave rise to Type-IV by evolving the modified medial-convex primary lamellae. The evolution of brachidia within individual evolutionary lineages must be clarified because two or more types can be present within a single family. Type-III and Type-IV are closely associated with the prolongation of the crura, representing innovative modifications of the feeding apparatus in response to possible shift in the position of the mouth towards the anterior, allowing for more efficient feeding on particles entering the mantle cavity from the anterior gape. Meanwhile, the modified primary lamellae adjusted/regulated the feeding currents. The absence of spires in some taxa with Type-IV brachidium might suggest that they developed a similar lophophore to that in some extant brachiopods, which can extend out of the shell.


2012 ◽  
Vol 499 ◽  
pp. 114-119 ◽  
Author(s):  
Ming Di Wang ◽  
Shi Hong Shi ◽  
X.B. Liu ◽  
Cheng Fa Song ◽  
Li Ning Sun

Numerical simulation of laser cladding is the main research topics for many universities and academes, but all researchers used the Gaussian laser light source. Due to using inside-beam powder feeding for laser cladding, the laser is dispersed by the cone-shaped mirror, and then be focused by the annular mirror, the laser can be assumed as the light source of uniform intensity.In this paper,the temperature of powder during landing selected as the initial conditions, and adopting the life-and-death unit method, the moving point heat source and the uniform heat source are realized. In the thickness direction, using the small melt layer stacking method, a finite element model has been established, and layer unit is acted layer by layer, then a virtual reality laser cladding manu-facturing process is simulated. Calculated results show that the surface temperature of the cladding layer depends on the laser scanning speed, powder feed rate, defocus distance. As cladding layers increases, due to the heat conduction into the base too late, bath temperature will gradually increase. The highest temperature is not at the laser beam, but at the later point of the laser beam. In the clad-ding process, the temperature cooling rate of the cladding layer in high temperature section is great, and in the low-temperature, cooling rate is relatively small. These conclusions are also similar with the normal laser cladding. Finally, some experiments validate the simulation results. The trends of simulating temperature are fit to the actual temperature, and the temperature gradient can also ex-plain the actual shape of cross-section.


1993 ◽  
Vol 12 (2) ◽  
pp. 241-255 ◽  
Author(s):  
C. Giles Miller ◽  
Richard J. Aldridge

Abstract. Collections of discrete conodont elements from the Upper Whitcliffe Formation of the Welsh Borderland indicate a septimembrate plan for the feeding apparatus of Coryssognathus, comprising Pa, Pb, Pc, M, Sa/Sb, Sb and Sc elements. Each element is paired, and relative frequencies suggest that there was a total of 16 elements in the apparatus, including two indistinguishable pairs of Sc elements. Associated small coniform elements appear to represent discrete denticles of crown tissue that were sequentially incorporated into multidenticulate elements during ontogeny.


1986 ◽  
Vol 7 (3) ◽  
pp. 241-253 ◽  
Author(s):  
Kurt Kotrschal ◽  
David G. Lindquist
Keyword(s):  

1997 ◽  
Vol 48 (5) ◽  
pp. 401 ◽  
Author(s):  
Jesse D. Ronquillo ◽  
Toshio Saisho

Gravid females of Metapenaeopsis barbata spawned in the laboratory by natural means and the larvae were reared from hatching to postlarval stage at 27·0–29·8˚C and 33·5–34·5 g kg -1 salinity. The larvae metamorphosed into first postlarvae, with a survival rate of up to 98·4%, after about 10 days following hatching and subsistence on only an algal diet of Tetraselmis tetrathele and Chaetoceros gracilis. Six naupliar stages, three protozoeal stages, three mysis stages and the first postlarval stage are described and illustrated. On the basis of morphological characteristics, larval stages of M. barbata can be distinguished from similar stages of closely related species in the family Penaeidae. As inferred from the morphology of the larval feeding apparatus, M. barbata is still a filter-feeder even at the first postlarval stage.


Author(s):  
Shichao Zhu ◽  
Wenliang Chen ◽  
Xiaohong Zhan ◽  
Liping Ding ◽  
Junjie Zhou

Laser cladding repair is an advanced technology for repairing Invar alloy moulds; however, the influences of various processing parameters on the quality of the Invar alloy moulds have yet to be determined. To explore the optimisation of laser cladding repair parameters, analyses of the geometric features and microstructure of the cladding layer were conducted. First, the influences of different powder feeding rates and scanning speeds on the dilution rate of the substrate were investigated by establishing a mathematical model of the laser power attenuation. Next, the influences of the parameters on the geometric features of the cladding layer were analysed. Finally, the influences of the parameters on the microstructure of the cladding layer were evaluated. At a laser power of 2300 W, a scanning speed of 3 m/min, and a powder feeding rate of 9 g/min, the best results of the width, height, dilution rate, roughness, and contact angle of the cladding layer were obtained. The results of this study indicated that excellent metallurgical bonding occurred between the cladding layer and the interface layer, and that the intended geometric features and desired microstructure of the cladding layer were obtained.


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