scholarly journals PENGEMBANGAN DESAIN PINTU MASUK BUBU LIPAT BERDASARKAN ASPEK TINGKAH LAKU RAJUNGAN

Author(s):  
Adi Susanto ◽  
Hery Sutrawan Nurdin ◽  
Ririn Irnawati ◽  
Mochammad Riyanto ◽  
Mohammad Ependi ◽  
...  

Blue swimming crab fishing using collapsible traps is widely used by fishermen because its caught live crabs and high selectivity. However, the passive fishing operation causes its low fishing productivity. The success of crabs fishing using folding traps is influenced by the suitability of the entrance design used. The size of the net and the inclination angle that are not by the crab's behavior will cause the crab to fail to be caught. This study aims to determine the more effective entrance design for catching crabs using the collapsible trap. The study was conducted in a laboratory using three mesh sizes, including 1.00, 1.25, and 1.50 inches with 30°, 40°, and 50° inclination angles. Each treatment combination uses different individual crabs. The study was conducted at night in an aquarium equipped with an infrared camera. Differences in mesh size and angle of inclination affect the crab's success rate and crawling speed in crossing the net field. The results showed that the highest percentage of crabs that successfully crossed the net field was obtained using a 1.25-inch mesh with an angle of 40°. The highest average crawling speed was also obtained at the same mesh size and angle of inclination. The use of a 1.25-inch mesh with an angle of 40° is expected to increase the effectiveness of catching crabs with folding traps.

2021 ◽  
Vol 10 (12) ◽  
pp. 2595
Author(s):  
Ryo Karakawa ◽  
Hidehiko Yoshimatsu ◽  
Keisuke Kamiya ◽  
Yuma Fuse ◽  
Tomoyuki Yano

Background: Lymphaticovenular anastomosis (LVA) is a challenging procedure and requires a sophisticated supermicrosurgical technique. The aim of this study was to evaluate and establish a discrete supermicrosurgical anastomosis method using the “suture-stent technique”. Methods: Forty-eight LVA sites of twenty patients with lower extremity lymphedema who had undergone LVA between July 2020 and January 2021 were included in this study. LVA was performed with the conventional technique or with the suture-stent technique. The patency of the anastomoses was evaluated using an infrared camera system intraoperatively. The success rate on the first try and the final success rate for each group were compared. Results: After full application of the exclusion criteria, 35 LVAs of 16 patients including 20 limbs were included in the analysis. The ratio of good patency findings after anastomosis in the suture-stent technique group was 100%. The incidences of leakage or occlusion on the first try were statistically greater in the conventional technique group (29.4%) than in the suture-stent technique group (0%) (p = 0.0191). All anastomoses achieved good patency in the final results. Conclusion: With its minimal risk of catching the back wall during the anastomosis, the suture-stent technique can be considered an optimal anastomosis option for LVA.


Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 200
Author(s):  
Zhongliang Feng ◽  
Xin Chen ◽  
Yu Fu ◽  
Shaoshuai Qing ◽  
Tongguan Xie

The joint arrangement in rock masses is the critical factor controlling the stability of rock structures in underground geotechnical engineering. In this study, the influence of the joint inclination angle on the mechanical behavior of jointed rock masses under uniaxial compression was investigated. Physical model laboratory experiments were conducted on jointed specimens with a single pre-existing flaw inclined at 0°, 30°, 45°, 60°, and 90° and on intact specimens. The acoustic emission (AE) signals were monitored during the loading process, which revealed that there is a correlation between the AE characteristics and the failure modes of the jointed specimens with different inclination angles. In addition, particle flow code (PFC) modeling was carried out to reproduce the phenomena observed in the physical experiments. According to the numerical results, the AE phenomenon was basically the same as that observed in the physical experiments. The response of the pre-existing joint mainly involved three stages: (I) the closing of the joint; (II) the strength mobilization of the joint; and (III) the reopening of the joint. Moreover, the response of the pre-existing joint was closely related to the joint’s inclination. As the joint inclination angle increased, the strength mobilization stage of the joint gradually shifted from the pre-peak stage of the stress–strain curve to the post-peak stage. In addition, the instantaneous drop in the average joint system aperture (aave) in the specimens with medium and high inclination angles corresponded to a rapid increase in the form of the pulse of the AE activity during the strength mobilization stage.


Author(s):  
Haibin Xuan ◽  
Jun Hu ◽  
Yong Yu ◽  
Jiaolong Zhang

Recently, numerous studies have been conducted to clarify the effects of corrugation wing on aerodynamic performances. The effects of the corrugation patterns and inclination angles were investigated using computational fluid dynamic method in gliding and hovering flight at Reynolds numbers of order 104. The instantaneous aerodynamic forces and the vorticity field around the wing models were provided to research the underlying mechanisms of aerodynamic effects of corrugated wing models. The findings can be concluded as follows: (1) the corrugation patterns have different effects on aerodynamic performance. The effect of noncamber corrugated wing is to decrease the lift and increase drag compared with a flat-plate when the angle of attack is less than 25° during gliding flight. The corrugated wing with a camber (corrug-2) after the valleys enhances the aerodynamic forces when angle of attack is higher than 35°. The valley inclination angle has limited effect on aerodynamic forces in gliding flight. (2) The lift forces of different corrugation patterns show significantly asymmetric during the upstroke and downstroke. The main reason leads to this phenomenon is the case that two sides of the corrugated wings are not symmetric around the pitching axis. The corrugated wing with only two valleys (corrug-1) changes the lift and drag very slightly. Corrug-2 produces larger peak during downstroke and smaller peak during upstroke. The increase in the inclination angle has limited effect on the aerodynamic forces. The possible reason for these small aerodynamic effects might be that the corrugated wings are smoothed by small vortices trapped in valleys. The main reason for the significant difference between plate and corrug-2 is that the recirculating vortices trapped in the saddle and hump reduce the pressure above the wing surface.


Author(s):  
Xiaoni Wu ◽  
Yean Khow Chow ◽  
Chun Fai Leung

Prediction of trajectory of drag anchor is important for the design and selection of drag anchor. Prediction based on yield envelope characterizing the anchor behavior under combined loading provides a promising method. However, the existing application of the yield envelope method ignores the effect of the fluke inclination angle by assuming a horizontally placed anchor fluke. This study aims to investigate the behavior of inclined fluke, which is the practical case during installation. The effects of the fluke inclination angle and embedment depth ratio on the anchor behavior in uniform clay under unidirectional loading and combined loading are investigated. It is found that the effect of the fluke inclination angle on the unidirectional capacity factors is mainly for anchor with embedment depth ratio less than 3. This results in the large difference of the size of the yield envelopes for fluke with same smaller embedment depth ratio but different fluke inclination angle, while the effect is minor on the shape of the yield envelope for such cases. However, there is large difference in the shape and size of the shallow yield envelopes for fluke with different embedment depth ratios and inclination angles.


2019 ◽  
Vol 488 (1) ◽  
pp. 572-589 ◽  
Author(s):  
James S Kuszlewicz ◽  
William J Chaplin ◽  
Thomas S H North ◽  
Will M Farr ◽  
Keaton J Bell ◽  
...  

Abstract The stellar inclination angle – the angle between the rotation axis of a star and our line of sight – provides valuable information in many different areas, from the characterization of the geometry of exoplanetary and eclipsing binary systems to the formation and evolution of those systems. We propose a method based on asteroseismology and a Bayesian hierarchical scheme for extracting the inclination angle of a single star. This hierarchical method therefore provides a means to both accurately and robustly extract inclination angles from red giant stars. We successfully apply this technique to an artificial data set with an underlying isotropic inclination angle distribution to verify the method. We also apply this technique to 123 red giant stars observed with Kepler. We also show the need for a selection function to account for possible population-level biases, which are not present in individual star-by-star cases, in order to extend the hierarchical method towards inferring underlying population inclination angle distributions.


2020 ◽  
Vol 12 (9) ◽  
pp. 168781402095988
Author(s):  
Pham Minh Duc ◽  
Le Hieu Giang ◽  
Mai Duc Dai ◽  
Do Tien Sy

The main purpose of this study is to investigate the influence of tool geometry (cutting edge angle, rake angle, and inclination angle) and to optimize tool wear and surface roughness in hard turning of AISI 1055 (52HRC) hardened steel by using TiN coated mixed ceramic inserts. The results show that the inclination angle is the major factor affecting the tool wear and the surface roughness in hard turning. With the increase in negative rake and inclination angles, the tool wear decreases, and the surface roughness increases. However, the surface roughness will decrease when the inclination angle increases to overpass a certain limit. This is a new and significant point in the research of the hard turning process. From this result, the large negative inclination angle (λ = −10°) should be applied to reduce the surface roughness and the tool wear simultaneously. With the optimal cutting tool angles in the research, the hard machining process is improved remarkably with decreases of surface roughness and tool wear 8.3% and 41.3%, respectively in comparison with the standard tool angles. And the proposed tool-post design approach brings an effective method to change the tool insert angles using standard tool-holders to improve hard or other difficult-to-cut materials turning quality.


Author(s):  
Taha Rezzag ◽  
Bassam A. Jubran

Abstract The present study numerically evaluates the influence of hole inclination angle with a hole imperfection on film cooling performance. Here, the hole imperfection due to laser percussion drilling is modelled as a half torus. Three hole inclination angles were investigated: 35°, 45° and 55°. Furthermore, every case was evaluated at three blowing ratios: 0.45, 0.90 and 1.25. Each case is compared to a baseline case where the hole imperfection is absent. The results indicate that the hole inclination angle has a strong influence on the film effectiveness performance when a hole imperfection is present. Centerline effectiveness plots reveal a maximum effectiveness deterioration of 89% for a blowing ratio of 0.90 in the vicinity of the hole exit. Dimensionless temperature contours show that the jet produced in the presence of an imperfection is much more compact causing the counter rotating vortex pair to be closer to each other. This enhances the jet to lift off from the plate.


Author(s):  
Wenlong Tian ◽  
Huang Zhang ◽  
Qianfeng Liu ◽  
Guang Hu ◽  
Wen He

Abstract We investigated a single droplet impinging on an inclined heated wall with different inclination angles. A high-speed camera was used to observe this impinging process at 10000 frames / second. The phenomena of the droplet spreading, shrinking, rebounding, boiling, break-up and splashing were observed. The effects of the wall temperature (Tw, 40–262 °C), the Weber number of the droplet (Wed, 0.66–589) and the wall inclination angle (α, 0–45.6°) on the spreading behavior of the droplet after impinging on the wall were analyzed. Energy conservation equation was used to analyze experimental results. The results show that increasing the inclination angle of the wall is beneficial to the forward spreading of the droplet along the wall, but not to the downward spreading. When α > 45.6°, the droplet will break through the flow resistance of the wall and slide down all the time. The increase of the wall temperature and the Weber number of the droplet is beneficial to the backward and forward spreading of the droplet. Increasing α, increasing Tw and decreasing Wed will promote the shrinking of the droplet after spreading. In addition, the experimental phenomenon also shows that the larger the wall inclination and the higher the wall temperature, the easier the droplet will break away from the wall.


Author(s):  
M. Ahmed ◽  
K. Lenard ◽  
I. Hassan ◽  
N. Esmail

A new theoretical investigation has been conducted for the prediction of the critical height at the onset of gas entrainment during single discharge from a stratified two-phase region through a branch installed on an inclined flat wall. Two models have been developed; a simplified point-sink model and a more-accurate finite-branch. The predicted critical height at the onset of gas entrainment was proven to be a function of Froude number (Fr) and density ratio of the interface fluids. The results of the predicted critical height at the onset of gas entrainment, at low values of Fr (<10), were found to be more accurate when using the finite-branch analysis compared to the results found using the pink-sink analysis. Whereas, with increasing Fr, the predicted values of both models converged to the same value. Furthermore, the point-sink analysis was demonstrated to be independent of wall inclination angle, while the finite-branch analysis showed a slight decrease in the value of the critical height with increasing wall inclination angle. Three different experimental data sets at wall inclination angles of zero, 45 and 90 degrees (i.e. side, inclined and bottom branches) were used in the following study for the comparisons between the experimental and theoretically predicted results. A good concurrence was illustrated between the experimental and theoretical values.


2011 ◽  
Vol 219-220 ◽  
pp. 633-637
Author(s):  
Li Xi Zhang ◽  
Shi Yuan Gao ◽  
Qing Yuan He ◽  
He Fei Zhang

It is studied the collected heat by collectors fixed on the outside wall of balconies when the shape and direction of balconies, and inclination angle of collectors are changed. Total heat collected by three walls of the rectangle balcony toward southeast or southwest is more than the one collected under other conditions. Total heat collected by rectangle balcony toward south would be increased when the inclination angles β of collectors are reduced. As β=70°, and the collectors were installed only on the south wall, to make water temperature above 60 °C in 150 L tank, extra energy needed is equivalent to 46.5 kg/a standard coal; if collectors were installed outside three walls of balcony, extra energy is not needed.


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