Papers by Keyword: Surface Strength

Abstract: Paper presents the method for obtaining maximum contact pressure of Novikov gears. Described surface strength calculation method is based on Hertz theory of two bodies being in point contact. What’s more the influence of gear position errors on maximum contact stresses has been presented. Also the comparison of Hertz stresses for Novikov and involute gears has been made.

Abstract: In order to prepare the polyurethane with less reliance on the oil resources, natural, renewable castor oil was used as raw materials to replace the traditional oil type polyols. The castor oil-based waterborne polyurethane was synthesized by the reaction of toluene diisocyanate (TDI), castor oil (C.O.), dimethylol propionic acid (DMPA) and triethyl amine (TEA). The results revealed that the best paper surface strength properties could be obtained under the condition that the mole ratio of TDI to C.O. was 3.0, prepolymerization temperature was 75°C and dosage of hydrophilic chain extender DMPA was 12.1%. In addition, picking speed of paper surface sized by this emulsion increased 2.53 times compared to the unsized paper, from 0.81m/s to 2.86 m/s, Printing ink absorption value and PPS value reduced in a reasonable scope, 60 s Cobb value was below 30 g/m².

Abstract: Brittle materials in general and particularly glass are very sensitive to dynamic particles impacts of different nature. The ancient objects in glass (building, monuments) and some precious objects are subjected to atmospheric aggressions such as humidity, sand particles, hail,…etc.). Their surfaces are however, often exposed to severe climatic conditions in an environment where the sand wind is a daily phenomenon or beach wind. Many degradation processes due to erosion affect significantly surfaces of buildings that are part of the Cultural Heritage.

Abstract: AKD is an important internal size for paper pulp fiber. With recycled economy development, regenerated paper fiber becomes an important resource. In this paper, AKD is used as a modification aid by internal sizing method. It shows that the change of the dosage of AKD influences regenerated paper fiber Cobb value, but has no influence to paper surface strength. The proper pH value is from 7 to 9. The temperature has no influence to regenerated paper fiber Cobb value and paper surface strength. Appropriate modified starch is good for AKD modification fiber and increase of the surface strength of paper made from modified fiber by AKD. Amphoteric starch is better than cationic starch. Other added substances such as PEI, MPEI and PAE can improve the modification of paper fiber modified by AKD. So the adsorption of modified paper fiber decrease and the surface strength of paper modified fiber increase.

Abstract: Five offset papers were applied to analyze the influences of the linting and picking problem based on the measurement of paper moisture, tightness, fiber composition and fiber length. The results showed that under the same conditions of paper making with the same raw materials, the printing surface strength increased and linting and picking problem reduced when the paper moisture or tightness are appropriately increased. The paper made with wood materials has a better surface strength and printability than bamboo and straw. The paper which contain less tiny fibers and long fibers, but more medium fibers is less likely to cause the problem of linting and picking.

Abstract: This article studied on these factors which influences the surface strength of packing paper. Through a series of tests, a model has been found. This model could guide the adjustment about fiber composition and beating process. And then a pilot scale test about this model has been carried out in Henan. The conclusion indicated that surface strength, printability and other strength indexes have been improved by adjustment of fiber composition and beating process scientifically. The ratio of softwood pulp has been reduced from 28% to 23%~25%. And the surface strength has been increased from 0.8~1.2m/s to 1.5~1.8m/s. Furthermore, when the ratio of softwood pulp is 23% and chemical-mechancial pulp is 7%, the packing paper still has a good printability.

Abstract: Silicon nitride is a type of engineering ceramic which has been used in ball bearing and other rolling contact applications owing to its good fatigue life, high temperature strength and tribological performance. In this paper, the mechanical properties of Hot Isostatically Pressed (HIPed) and Sintered and Reaction Bonded Silion Nitride (SRBSN) have been studied. The elastic modulus and poisson’s ratio of three types of commerical grade HIPed silicon nitride, and ground SRBSN with three surface condidtions were measured using a Resonance Ultrasound Spectroscopy (RUS). The RUS measurement reveals the variation of elastic properties across different types of HIPed silicon nitride specimens. The surface strength of silicon nitride are studied using a C-sphere specimen, and the results show that SRBSN with three different surface finishing conditions show varied surface strength. The RUS and C-sphere techniques can potentially be used to sample the quality and consistency of ball bearing elements.