Pressure and angle of the seed-fertilizer drill press wheel on corn emergence

ABSTRACT In precision seed-fertilizer drills, the soil compaction mechanism is responsible for closing the furrow, pressing the soil over the seed. Among the available models, the most used is the V-type wheel system, with several options to regulate the wheel opening angle and pressure exerted on the soil. This study was carried out in the experimental area of the Federal University of Fronteira Sul - Campus Cerro Largo, in an clayey Red Latosol. Parameters related to corn emergence and the seedbed characteristics were evaluated at different regulations of opening angle and pressure of the compaction mechanism. The results indicate that mechanism regulations had no influence on emergence speed, emergence speed index and population of corn plants, under the studied conditions. However, the treatment with highest load and parallel alignment of the wheels caused lower values of elevated area and swelling. Treatments with 15° opening angle caused accumulation of soil in the center of the row, affecting the elevation height.

CT-Compatible Medical Drilling Stylet

This paper describes the design of a compact, lightweight CT-compatible, drill-press that is designed to be used in either a hand-held or stand-alone mode to assist with percutaneous bone based interventions. Previous medical drilling tools that have been developed have a metal structure and typically have one actuator for advancing the drill (feed) and another for rotating it (speed). After defining the device functional requirements and specifications, a deterministic design process was followed to generate several design concepts that were then evaluated based on their ability to satisfy the functional requirements. A final concept that uses a custom screw-spline to achieve helical motion of a shaft that is attached to a standard orthopedic drill was selected for prototyping. The design uses a single actuator to drive both the screw and spline nuts through two different gear ratios, resulting in a fixed ratio between the feed and speed. Apart from the motor which is placed away from the central drill axis, the device is largely made from plastic materials. A custom experimental setup was developed that enabled drilling into bone inside a CT scanner to be examined. Results showed that the device was successfully able to penetrate thick cortical bone and that its structure did not appreciably distort the medical images.

Improvement on the Manufacturing Process of the Dental Surgical Guide Made by a 5-Axis CNC Drill Press

Traditionally, three CT markers are attached to a surgical guide of dental implant surgery to correlate the implant positions in CT images and the drill positions of a drill press. To allow the drill press to know the positions of the CT markers, users need to use the press to probe the positions of them manually. This process is inaccurate and time-consuming. The objective of this research was to develop a new process to eliminate the traditional probing process. This new process uses two identical pairs of locating pins both in the plaster mold cavity and on the fixture of a CNC drill press, respectively. Since the position of the drill bit relative to the locating pins and the positions of the locating pins relative to the CT markers are designed by us, the drill press knows the positions of the CT markers without probing them. According to the preliminary evaluation results, the mean errors of the location and angle of the drilled holes were 0.696 mm and 1.23°, which indicate that this innovative idea presented in this paper is feasible and promising.

Recognition for Spindle Speeds of Drill Press Based on Sound Signals Produced from Drilling

Effects of running state and spindle speeds on the sound signals produced from a drill press are investigated. And the obtained sound signals by using of a sound level meter are analyzed in both time domain and frequency domain. It is evident that there is more high frequency energy for drilling sound signals with load than without load. And spindle speeds still affect their energy distribution of drilling sound signals. Using wavelet decomposition and wavelet packet decomposition, drilling sound signals are decomposed into a number of frequency bands. And energy percentages of the divided frequency bands are extracted to be the effective characteristics to recognize spindle speeds. Meanwhile, training error of different BP networks is compared to obtain the effective network for recognition spindle speeds. By using of the obtained network structure named 16-30-5, the study rate for training samples and the recognize rate for testing samples are all above 95%.

Penetrometer Measurement of Apple and Kiwifruit Firmness: Operator and Instrument Differences

Flesh firmness is a characteristic used to indicate fruit quality. Experimental design and data analysis are important when comparing devices that measure fruit firmness. We compared the Effegi penetrometer operated by hand, mounted in a drill press and then operated by hand, and mounted on a motorized drive and operated remotely; the hand-operated EPT pressure tester; the Instron with an Effegi probe; and a hand-operated prototype of the twist tester. Devices varied in operator differences and precision. Comparisons between devices were at the within-fruit level of variability and, therefore, more precise than comparisons where different device-operators used different fruit. We demonstrate statistical methods that are appropriate for making the comparisons of interest and discuss the possible cause of differences between operators and between devices. We also discuss how the mechanical properties of the devices may affect results and consider implications for their practical use. In this study, we found the precision of discrimination between soft and hard apples was best using the Instron in 1992, while the Instron and hand-held Effegi penetrometer were comparable in 1991. For kiwifruit, the hand-held Effegi penetrometer consistently gave the most precise measurements of softening in 1991, while the twist test was the most precise in 1992.