Polyphenylene ethers with imide linking groups

Novel polyphenylene ethers with imide linking units are disclosed. These polymers incorporate the solvent and thermal resistance of polyimides and the processability of polyphenylene ethers. Improved physical properties over those of the prior art are obtained by incorporating meta linked ethers and/or polyphenylene oxides into the polymer backbone. A novel process for making polymers of this type is also disclosed. The process is unique in that the expected need of high process temperatures and/or special atmospheres are eliminated

Process of end-capping a polyimide system

A process of endcapping a polyimide system with an endcapping agent in order to achieve a controlled decrease in molecular weight and melt viscosity along with predictable fracture resistance of the molded products is disclosed. The uncapped system is formed by combining an equimolar ratio of 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfide dianhydride (BDSDA) and 1,-bis (aminophenoxy) benzene (APB) dissolved in bis (2-methoxyethyl)ether. The endcapped system is formed by dissolving APB in bis-(2-methoxyethyl)ether, adding the BDSDA. By varying the amount of endcapping from 0 to 4%, molecular weight is decreased from 13,900 to 8660. At a processing temperature of 250 C, there is a linear relationship between molecular weight and viscosity, with the viscosity decreasing by two orders of magnitude as the molecular weight decreased from 13,900 to 8660

A study of polymers containing silicon- nitrogen bonds progress report, nov. 4 - dec. 3, 1964

Polymers containing silicon-nitrogen bonds as liquid and plastic materials in space and aviation technolog

A study of polymers containing silicon- nitrogen bonds Annual summary report, May 4, 1965 - May 3, 1966

Polymers containing silicon-nitrogen bonds as elastomers with high thermal stability for aerospace application

Greenhouse Robot Navigation Using KLT Feature Tracking for Visual Odometry

A visual odometer was developed for an autonomous greenhouse sprayer to estimate vehicle translation and rotation relative to the world coordinate system during navigation. Digital images were taken from a CCD camera mounted on the robot. 7 x 7 pixel features were selected in the image using the KLT algorithm (Csetverikov, 2004). Features were tracked from image to image by finding the best 7 x 7 pixel match of the feature within a 25 x 25 pixel search box. By analyzing the movement of these features, vehicle rotation and translation were estimated. Five features were tracked with the odometer. Tests were run to verify the visual odometer’s accuracy during translation, rotation, and on various surfaces. The visual odometer ran at an average of 10 Hz during experimentation. Translation tests of the odometer in a lab environment gave an average error of 4.85 cm for a 30.5 cm forward translation and 12.4 cm average error for a 305 cm translation. Rotation tests of the odometer in a lab environment gave an average error of 1° for a 45° rotation and an 8° error for a 180° rotation about the vehicle z-axis. Tests completed on concrete, sand, and gravel demonstrated adaptability of the odometer on different ground surfaces that are common in greenhouses. The visual odometer was successfully integrated into a visual navigation system for intersection navigation of an autonomous greenhouse sprayer

Synthesis and characterization of a polyethersulfoneimide

Two similar polyimide systems were synthesized and characterized. The only structural difference was a sulfide linkage in the anhydride derived portion of the first system versus a sulfone linkage in the second. Their physical, mechanical, melt-flow and thermal properties were determined and also their resistance to some of the more common solvents. The flow properties of these polyimides indicate them to have potential for melt processability

Synthesis and characterization of a melt processable polyimide

A melt processable polyimide which contains sulfur and oxygen bridges between the aromatic rings (BDSDA/APB) was synthesized and characterized. Its physical, mechanical, thermal and flow properties were determined as was its resistance to some of the more commonly used solvents. The melt flow properties were measured for the temperature range 250 C - 350 C and under the conditions (stress/strain) encountered in commercial processes

Wagon-Based Silage Yield Mapping System

Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 7 (2005): Wagon-Based Silage Yield Mapping System by W. S. Lee, J. K. Schueller, T. F. Burk

A week-end off: the first extensive number-theoretical computation on the ENIAC

The first extensive number-theoretical computation run on the ENIAC, is reconstructed. The problem, computing the exponent of 2 modulo a prime, was set up on the ENIAC during a week-end in July 1946 by the number-theorist D.H. Lehmer, with help from his wife Emma and John Mauchly. Important aspects of the ENIAC's design are presented-and the reconstruction of the implementation of the problem on the ENIAC is discussed in its salient points

A Machine Vision Algorithm Combining Adaptive Segmentation and Shape Analysis for Orange Fruit Detection

 Over the last several years there has been a renewed interest in the automation of harvesting of fruits and vegetables. The two major challenges in the automation of harvesting are the recognition of the fruit and its detachment from the tree. This paper deals with fruit recognition and it presents the development of a machine vision algorithm for the recognition of orange fruits. The algorithm consists of segmentation, region labeling, size filtering, perimeter extraction and perimeter-based detection. In the segmentation of the fruit, the orange was enhanced by using the red chromaticity coefficient which enabled adaptive segmentation under variable outdoor illumination. The algorithm also included detection of fruits which are in clusters by using shape analysis techniques. Evaluation of the algorithm included images taken inside the canopy (varying lighting condition) and on the canopy surface. Results showed that more than 90% of the fruits visually recognized in the images were detected in the 110 images tested with a false detection rate of 4%. The proposed segmentation was able to deal with varying lighting condition and the perimeter-based detection method proved to be effective in detecting fruits in clusters. The development of this algorithm with its capability of detecting fruits in varying lighting condition and occlusion would enhance the overall performance of robotic fruit harvesting