Real Time Weed Detection using a Boosted Cascade of Simple Features

Weed detection is a crucial issue in precision agriculture. In computer vision, variety of techniques are developed to detect, identify and locate weeds in different cultures. In this article, we present a real-time new weed detection method, through an embedded monocular vision. Our approach is based on the use of a cascade of discriminative classifiers formed by the Haar-like features. The quality of the results determines the validity of our approach, and opens the way to new horizons in weed detection

Design of Controlled Pre-Split Blasting in a Hydroelectric Construction Project

Geologic conditions and design requirements around upstream Nachtigal Falls, in Cameroon, for the hydroelectric construction project on the Sanaga River dictated close control of blasting procedures with very precise geometry to obtain safe and economical excavation lines. Various techniques of pre-split blasting were used in the initial stage of all major excavations. Hole diameters for pre-splitting were 89 mm, and hole spacing ranged from 0.8 to 1m. Explosive charges varied from 1 to 7 kg per hole, and the detonating cord linear charge ranged from 12 to 60g. The contour blasting technique is aimed at controlling overbreak and improving remaining slope stability. Over-break or over-excavation needs to be controlled since its occurrence compromises the operations in terms of safety (instability in the remaining slope; loosening rocks that increase the risk for operational people; an irregular free face for subsequent blasting); and costs (need for reinforcement of the remaining rock structure through costly sustainment systems; increase in concrete volumes in civil works). This paper discusses in detail the design and field implementation of pre-split blasts successfully carried out to achieve clean vertical walls in moderately dipping, though complexly sheared and jointed gneiss. Based on the results of the experiments, we were able to design a pre-splitting pattern both experimentally and in a very cost-effective manner. It is felt that the methods developed on this project could have useful applications on other major construction projects. Doi: 10.28991/CEJ-2023-09-03-05 Full Text: PD

Etude expérimentale de l'ébullition libre de l'azote liquide en régime transitoire sur des rubans en laiton

Le phénomène d'ébullition libre est utilisé pour le refroidissement des parois dans plusieurs domaines tels que l'industrie pétrolière et la production d'énergie électrique. Pour quantifier les échanges thermiques, nous avons réalisé une étude expérimentale d'ébullition libre de l'azote liquide en régime transitoire sur un ruban en laiton en imposant la densité de flux. Les résultats montrent que l'ébullition débute avec un certain retard qui engendre des surchauffes pariétales importantes et que lors de son déclenchement, la température est fortement liée à la vitesse de chauffage et au temps d'attente entre la procédure préliminaire et l'échelon de flux imposé. Pour éviter une forte surchauffe au déclenchement de l'ébullition, il est possible de maintenir une température surfacique supérieure à une certaine limite. Il peut ainsi être recommandé de toujours dissiper un faible flux pour que la température surfacique soit suffisante afin de faciliter l'activation des sites de nucléation.Pool boiling phenomena is used for cooling surfaces in several fields such as petroleum industry and the electricity production. In order to quantify the heat exchange, we made an experimental study of the nitrogen pool boiling on a brass ribbon in transient conditions for a fixed flux density. The results show that boiling begins with a certain delay which generates important parietal overheating and, at the time of its release, the temperature is strongly related to the heating rate and the waiting period between the preliminary procedure and the imposed flux. To avoid the strong overheating with the onset nucleate boiling, it is possible to maintain a surface temperature higher than certain limit. Thus, It can be recommended always to dissipate a weak flux so that the surface temperature is sufficient in order to facilitate the activation of nucleation sites.NANCY1-SCD Sciences & Techniques (545782101) / SudocSudocFranceF

Experimental and statistical analysis of blast-induced ground vibrations (BIGV) prediction in Senegal’s quarry

Extractive industries often use explosives to destroy rocks, and productivity requirements tend to increase the charges of the explosives. The blasts induce vibrations, which result in a potential damage of the surrounding structures. Therefore, the prediction of vibrations should be described with accuracy, in order to ensure the safety of engineered structures. However, the prediction of vibrations’ levels remain a complicated issue, because it involves numerous parameters correlated to the quarry site

Experimental and statistical analysis of blast-induced ground vibrations ( BIGV

Extractive industries often use explosives to destroy rocks, and productivity requirements tend to increase the charges of the explosives. The blasts induce vibrations, which result in a potential damage of the surrounding structures. Therefore, the prediction of vibrations should be described with accuracy, in order to ensure the safety of engineered structures. However, the prediction of vibrations' levels remain a complicated issue, because it involves numerous parameters correlated to the quarry site. In this paper, statistical analysis based on the peak particle velocity (PPV) and the attenuation law has been carried out to assess the safety charges (Q) for different distances (R) between the blast and the considered structure to secure. Moreover, the experimental investigations were conducted on the quarry site of "Sococim", which is located on the south coast of Senegal. To ensure the safety of the "Conveyor belt" and "Panel 1 (Upper exploitation level)" sites, the PPV should be less than 10 mm/s. In fact, the attenuation model has been used to assess the safe charge weights of the explosive (Q) to be used at the "Conveyor belt" site and at the "Panel 1 (Upper exploitation level)" site. Therefore, the safe charge weights per delay (Q) were respectively 116 kg and 13.75 kg

Experimental and statistical analysis of blast-induced ground vibrations (BIGV) prediction in Senegal's quarry

Extractive industries often use explosives to destroy rocks, and productivity requirements tend to increase the charges of the explosives. The blasts induce vibrations, which result in a potential damage of the surrounding structures. Therefore, the prediction of vibrations should be described with accuracy, in order to ensure the safety of engineered structures. However, the prediction of vibrations' levels remain a complicated issue, because it involves numerous parameters correlated to the quarry site. In this paper, statistical analysis based on the peak particle velocity (PPV) and the attenuation law has been carried out to assess the safety charges (Q) for different distances (R) between the blast and the considered structure to secure. Moreover, the experimental investigations were conducted on the quarry site of "Sococim", which is located on the south coast of Senegal. To ensure the safety of the "Conveyor belt" and "Panel 1 (Upper exploitation level)" sites, the PPV should be less than 10 mm/s. In fact, the attenuation model has been used to assess the safe charge weights of the explosive (Q) to be used at the "Conveyor belt" site and at the "Panel 1 (Upper exploitation level)" site. Therefore, the safe charge weights per delay (Q) were respectively 116 kg and 13.75 kg