ABOUT FORM LIBIT AND METHODS DETERMINATION PARAMETER WIND THREADS OF THE BASE ON LIBIT-WARPING DRUM

Considered determination form wind of the threads libit on libit-thread base drum and thickness of rolling with consideration of the machine construction and forms of thread rolls of libits. Samples are provided for determining the scope and thickness of libit rolls. KEYWORDS: fabric, avrov fabric, avrband, libit, libit reels, roll layers, libit thread base, libit wrapping roll, cylindrical roll, breaking of roll–reels, segment, sector, libit scope.

Apoderus coryli (L.) – a Biologically Little Known Species of the Attelabidae (Coleoptera)

Hazel-leaf roller weevil (Apoderus coryli /L./) is a noteworthy species from the perspective of biology and forestry; it belongs to the family Attelabidae. Its occurrence, development and harmfulness were studied in surroundings of Brno city in 2011 and 2012. Imagoes of the first generation and those of not very numerous second generation are observed to winter in the area under study. From the beginning of May to the end of July they occur on the host woody plants (mainly on Carpinus betulus and Corylus avellana). The males and females consume on average 21 and 33 cm2 of leaves, respectively. The fertilized females cut into the leaf blade in an original manner, and bite into the main and side leaf veins. They fold the withering part of the blade lengthwise to the adaxial face first, and then forming the folded blade into a short cylindrical roll. In the initial phase of rolling, the females lay up on average 1.0 egg into the leaf rolls on C. betulus (1.2 on C. avellana). In total, they make around 30 rolls. The larvae emerge on average within 10 days. In the course of 3 to 4 weeks, they pass through two instars only and damage on average 4 cm2 of leaves. This work describes the occurrence and development of the beetles of the first and second generation. It provides an assessment of the mortality of the individual development stages of A. coryli within the rolls. It was demonstrated that rolling of the leaves causes on average 9 times more damage to the trees than maturation feeding of the beetles.

Design and Fabrication of a Roller Imprinting Device for Microfluidic Device Manufacturing

Microfluidic devices are gaining popularity in a variety of applications, ranging from molecular biology to bio-defense. However, the widespread adoption of this technology is constrained by the lack of efficient and cost-effective manufacturing processes. This paper focuses on the roller imprinting process, which is being developed to rapidly and inexpensively fabricate micro-fluidic devices. In this process, a cylindrical roll with raised features on its surface creates imprints by rolling over a fixed workpiece substrate and mechanically deforming it. Roller imprinting aims to replace processes that were developed for laboratory scale prototyping which tend to not be scalable and have high equipment requirements and overheads. We discuss the limitations of PDMS soft lithography in large-scale manufacture of microfluidic devices. We also discuss the design, fabrication, and testing of a simple roller imprinting device. This imprinter has been developed based on the principles of precision machine design and is implemented using a three-axis machine tool for actuation and position measurement. A framework for the micro-machining of precision imprint rolls is also presented.

Response and analysis of multi-degree-of-freedom cylindrical roll grinding system

The dynamic response of a roll grinding system with non-constant delay is investigated on the basis of a non-linear multidegree-of-freedom (MDOF) model. A delay effect originates from shape error regeneration on the surface of the roll, and the delay varies with the rotational speed of the roll. A five-degree-of-freedom (5DOF) system is considered. Two equations describe the vibration response of the roll in rotating coordinates, and the other three express the rotational rigid-body vibration system of the roll, the grindstone and its motor. Rotational speed controllers of drives are introduced. In order to obtain the non-constant time delay and the delayed total penetration of the grindstone, a two-step cubic interpolation method is applied. Numerical results are presented, discussed and compared with different cases. Time domain responses are used to illustrate the stability of the system with grinding parameters.