公路反光标线涂料

<正> 公路反光标线涂料是用以公路路面标线并能夜间反光的一种涂料。由于当代公路运输事业的发展,公路反光标线涂料在世界发达国家已到较为普遍的应用,并取得了提高车速,减少交通事故的明显效果。近几年来,随着我国公路运输事业的发展,路面反光标线涂料也已着手开发。 1 概述     

我国道路标线涂料的发展和应用

综述我国道路标线涂料的发展和应用概况，简要介绍新型道路标线涂料，提出了促进道路标线涂料发展的建议。     

德国、法国道路标线涂料的应用考察

介绍了德、法两国道路标线涂料的品种及应用 ,指出我国应开发符合国情的凸起结构型标线涂料、不沾污标线涂料等新型道路标线涂料系列。     

浅谈路面标线涂料质量的检验标准

<正> 随着我国公路交通运输事业的发展,交通流量急剧增加,人们对交通安全的设施提出了新的更高的要求。同时对路面标线涂料的质量也提出了更高的标准,以适应现代公路交通运输事业的发展。一、建立检验标准的必要性在我国,路面标线的大量使用还是近几年的事,《道路交通标线》的国家标准于86     

道路交通标线涂料的新动向

道路交通标线涂料发展的新动向是要求所划设的标线视认性更好,具有更多的警示功能,可以铺设彩色防滑路面,涂改原有的标线,环保的水性标线涂料,性能优良的双组分标线涂料,划线机的多功能化等。根据作者多年从事公路交通安全设施设计和标线涂料施工的经验以及国外考察的所见所闻,提出了道路交通标线合理设计和施工的建议,并提出要注意职工的健康安全管理。     

我国路面标线涂料的发展

我国的路面标线涂料主要是以Ｃ５ 石油树脂为基料的热熔型和以丙烯酸树脂为基料的常温溶剂型两种类型， 对两者的性能优劣作了分析比较， 并指出， 今后该涂料的高固体及水性化发展是必然趋势。     

铁路、公路涂料

一种水性长效反光道路交通标线涂料；我国道路标线涂料发展应用现状     

道路标线涂料的研究进展

综述了道路标线涂料的研究概况，介绍了道路标线的定义、分类以及各种类型道路标线涂料的国内外研究状况，并概述了热熔型道路标线涂料及其配方选择原则。简单介绍了几类双组分道路标线涂料，提出了抽出莲路标线涂料存在的一些问题。     

道路交通标线涂料的应用研究进展

快干型水性标线涂料技术绿色环保，具有持久的玻璃珠黏附力和优异的反光性，夜间辨识性高，经久耐磨，有助于提升道路安全，且施工效率高，综合成本较低，在标线材料应用中占据主导地位。本文总结了热熔型、溶剂型、水性和双组分四大类道路标线涂料的应用特点，重点介绍了水性标线涂料成膜物快干型丙烯酸乳胶及其技术要求，以及水性标线涂料在应用中存在的问题并分析了原因。     

热熔型路标漆施工与生产(Ⅱ)

5 热熔型标线涂料的施工 　　热熔型标线涂料是一种无溶剂的固体涂料,通过加热到180～220℃时熔化为黏稠的液体后,再通过施工机械涂覆或喷涂于路面而形成标线。其干燥机理不同于液体涂料靠溶剂或水的挥发干燥,而是冷凝固化干燥,所以该涂料的施工在施工机械及施工方法上都具有特殊性。     

Prediction of gas flow directions in gas assisted injection molding when cavities and runners are involved

In the prediction of gas flow-direction for gas-assisted injection molding (GAIM), the statement“Gas goes to the direction of the last area to fill with resin”, has been accepted as a correct one. When there exists more than one area to fill with resin, a mold design engineer for GAIM technologies has to determine to which direction gas goes that commercial software for GAIM (e.g., Moldflow) may be utilized for its mold design. However commercial software is generally expensive and is sometimes hard to become familiar with. As a rule of thumb, it is suggested that the resistance to the initial velocity of melt polymer at the nearest geometry to a gas injection point should be used as its criterion since gas goes in the direction of least resistance to initial resin-velocity. Neither the flow rate nor the resistance to flow rate can be a criterion in the prediction. Thus the statement“Gas goes to the direction of the least resistance to flow rates”, should be corrected to“More flow rate goes to the direction of the least resistance to flow rates.”, The rule of thumb suggested in this paper was verified by using commercial software, Moldflow, in the prediction of gas flow directions in GAIM under geometries where cavities and runners were involved. When the ratio of initial resin-velocity is so close to unity it is proposed as the adapted rule of thumb to calculate new emerging resin-velocities and resistances to resin-velocity at the first coming change of diameters in series of pipes and to compare those for upper and lower sides each other to predict the gas direction. Thus the judgment as to which point is the point where gas starts to choose a preferred direction is very important in the prediction.     

Consolidation of sand formation using freon'll gas hydrate

Freon 11 gas hydrate was used to block the pores of four size ranges of sand from 24 mesh to 60 mesh. A 50.8 mm deep bed of sand when thus “frozen” with hydrate could sustain a dfferential water pressure of at least 6895 kPa. A subcooling of about 5 to 6°C below its thermodynamic formation temperature was required to cause the hydrate to form such a plug. Once formed, the hydrate remained stable at temperatures up to its decomposition temperature. The time required for the hydrate crystal to grow to a size large enough to block the pores of the bed was about two hours. The amount of hydrate forming agent required to block the sand pores was found to be approximately that calculated from the ideal composition of the hydrate.     

Adhesives in construction: A contractor's viewpoint

The development of epoxy- and polyester-based adhesives has dramatically widened the scope of adhesive bonding in the civil engineering industry but the technology of the adhesives used has often been more appropriate to the workshop than to the construction site. There is a need for the suppliers of structural adhesives to recognize this and to develop compositions and application techniques more amenable to site use. It is equally necessary for the construction industry to make more effort to understand these materials, to take advantage of their outstanding properties, and hence to use them successfully for the construction and repair of concrete structures.     

Effect of autoxidation prior to deodorization on oxidative and flavor stability of soybean oil

Summary Oxidation prior to deodorization was shown to be detrimental to the flavor and oxidative stability of soybean oil. The increase in the nonvolatile carbonyl content of freshly deodorized oils was proportional to the peroxide value of the oils before deodorization. Rate of loss of flavor and oxidative stability of the oil were related to the extent of carbonyl development. All oils, whether or not they had been submitted to any known oxidation, contained some nonvolatile carbonyls. The loss in stability was not due to a loss of the antioxidant tocopherol. Oxidized soybean oil methyl esters were shown to develop nonvolatile carbonyl compounds upon heating at deodorization temperatures. The addition of isolated methyl ester peroxide decomposition products to deodorized soybean oil reduced its flavor and oxidative stability in proportion to the amount added. The results obtained were parallel and similar to those obtained by oxidizing soybean oil prior to deodorization. Flavor deterioration and undesirable flavors were typical of aging soybean oil whether or not the oils were oxidized before deodorization or whether an equivalent amount of nonvolatile thermal decomposition products was added to the oil. These oxidatively derived, nonvolatile carbonyl materials are believed to enter into the sequence of reactions that contribute to flavor instability and quality deterioration of soybean oil. The structure of these materials is not know. This work indicates the importance of minimizing autoxidation in soybean oil particularly before deodorization to insure good oxidative and flavor stability. Presented at fall meeting, American Oil Chemists’ Society, October 20–22, 1958, Chicago, Ill. This is a laboratory of the Northern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

Fracture of mica-reinforced polypropylene: Mica concentration effect

Concepts of post-yield fracture mechanics were used to characterize the crack initiation and propagation resistances of mica-reinforced polypropylene containing different mica concentrations. Although mica addition leads to an apparently brittle composite, the crack initiation resistance is slightly increased with mica concentration up to 10 percent by weight; and significant improvement in crack propagation performance was found for polypropylene reinforced by up to 20 percent of mica in comparison to that of virgin polypropylene. The debonding of the interface between mica flakes and the matrix leads to a micro-ductility ahead of the crack tip in which the matrix is able to pull-out from mica particles and to stretch. This micro-ductility also prevents the brittle, unstable crack propagation, which is due to the coalescence of voids in pure polypropylene. Above 20 percent of mica, the reduction of the effective amount of the matrix material results in a substantial drop in the resistance to crack growth of mica-reinforced polypropylene.     

Surface crosslinking of polyethylene and adhesive joint strength

Exposure of polyethylene film to UV radiation at wavelengths of ≤2537 Å is sufficient to induce surface crosslinking and to facilitate the formation of strong adhesive joints to these surfaces with conventional adhesives. Reduction of the vapor pressure in the reaction vessel to about 1 torr apparently maximizes the efficiency of the crosslinking process. Examination of the treated films which have been exposed for times necessary to form strong adhesive joints has revealed an absence of surface oxidation. It appears that crosslinking to improve the mechanical strength of the surface region of the polyethylene is sufficient to allow the formation of strong adhesive joints.     

SOME EXPERIMENTS ON THE FIRECRACKING OF TERRA COTTA1

Firecracking .—occurs on terra cotta under certain conditions and is characterized by the appearance of sharp, hair-line cracks extending into the body. The experiments were made by firing large typical pieces of terra cotta made from various clays and grogs and cooling them at different rates. The tendency to firecrack was observed after weathering. The absorption, porosity and transverse strength of the various bodies were determined. Rate of Cooling .—All bodies similar to those used in practice showed a tendency to firecrack when cooled rapidly and all were free from cracks when cooled slowly. The rate of cooling has a much greater effect on the tendency to firecrack than the composition or physical properties of the body. Effect of Clay .—Three of the four sandy clays showed a decided tendency to firecrack, due to the difference in the expansion and contraction behavior of sand and clay in heating and cooling. The sandy clays showed more tendency to firecrack than the non-sandy, vitrifying clays. The tendency of a clay to develop firecracks in a body depends to a very large extent upon the character of the clay itself, regardless of the impurities it contains. The presence of sandy material and the character of the clay appear to have a much greater effect on the tendency to firecrack than the absorption, porosity or transverse strength of the body. No relation was found to exist in these experiments between the porosity and transverse strength of a body and its tendency to firecrack. Effect of Grog .—The greatest tendency to firecrack was found on a body with all grog finer than 40-mesh, but a body with all grog coarser than 40-mesh did not appear to have much less tendency to firecrack than the average. Increase of grog reduced the tendency to firecrack. The kind or source of the grog used does not have as much effect on the tendency to frecrack as the size and amount. The kind of grog is of much less importance in this respect than the kind of clay.     

Long-term residual value of North Carolina and Queensland rock phosphates compared with triple superphosphate

The effectiveness of large single applications of North Carolina reactive rock phosphate, Queensland non-reactive rock phosphate, and Calciphos, were compared to the effectiveness of superphosphate in field experiments in south-western Australia for up to 11 years after application. As measured using plant yield, superphosphate was the most effective fertilizer in the year of application, and relative to freshly-applied superphosphate, the effectiveness of the superphosphate residues declined to be about 15 to 65% as effective in the year after application, and 5 to 20% as effective 9 to 10 years after application. Relative to freshly-applied superphosphate, all the rock phosphates were 10 to 30% as effective in the year of application, and the residues remained 2 to 20% as effective in the 10 years after application. The bicarbonate soil test reagent predicted a more gradual decrease in effectiveness of superphosphate of up to 70% 10 years after application. For rock phosphate, the reagent predicted effectiveness to be always lower than for superphosphate, being initially 2 to 11% as effective in the year after application, and from 10% to equally as effective 10 years later. Therefore rock phosphates are unlikely to be economic alternatives to superphosphate in the short or long term on most lateritic soils in south-western Australia.     

基于大数据分析的废旧塑料利用率算法

概述了我国废旧塑料再生利用现状及应用领域,通过大数据回归分析建立了废旧塑料利用率的算法模型,测算我国2009—2019年的废旧塑料利用率.2009—2014年,废旧塑料利用率从12.0％升至16.0％,2015—2019年略微下降.2009—2015年,塑料回收利用量持续增长,2016年,回收利用量有所下降,2017—...