Ornamental potential of Schomburkgia crispa Lindl.

Orchids are one of the groups of plants with the greatest commercialization potential. They have floral characteristics highly valued in the sector of flowers and ornamental plants. However, exotics species are the most commercialized. The native species are still little explored for their ornamental potential. Thus, this work describes the vegetative and floral morphological characteristics of Schomburgkia crispa Lindl. aiming at evaluating its ornamental potential. For such, seven individuals were chosen. The quantitative characters were evaluated in all plants, totaling fifty pseudobulbs and eighty-eight flowers. During flowering, the most representative plant was chosen for the visual evaluation of its morphological features through photographs. A floral diagnosis sheet based on photos of fresh flowers was prepared by keeping the maximum level of morphological details. At the end of the experimental period, averages and standard deviations were calculated for each character evaluated. The species S. crispa presented, on average, plants 46.17 cm long, 31.50 cm wide, and with 88 cm of diameter. For flowering characters, the species presented in general 16.50 flowers per plant, 14.67 per flower stem, and 4.66 flowers opened per day, with an average durability of 32 days. Thus, we conclude that the species S. crispa has a great ornamental potential for use in ornamental horticulture.

Evaluation of the Cavitation Resistance of INCONEL 718, in Delivered and Respectively Heat Treated Condition

Inconel 718 is a very difficult metal for machining because of its high plasticity. Lately, more and more researchers are interested in using it for cavitation parts, such as the plugs and drawers of the valves. For this purpose, thermal volumetric treatments have been initiated to facilitate mechanical machining, aiming simultaneously to obtain good compression and cavitation resistance results. Therefore, this paper presents the results of cavitation erosion behavior and cavitation resistance of ICONEL 718, subjected to two thermal treatment regimes, differentiated by the duration (temperature 800 °C and residence times 5 hours, and respectively 10 hours). The assessment of the cavitation resistance provided by each heat treatment regime is based on the average durability cavitation parameter, as defined by K. Steller. The research is achieved by using the standard vibrator device with piezo - ceramic crystals from the Cavitation Laboratory of the Politechnica University of Timisoara.

Assessment of the Cavitation Resistance of Stainless Steel X5crni18-10, Subjected to Thermal Sensitization Based on Average Durability

Among the uses of stainless steel GX5CrNi18-10 one mentions the hydraulic machine blades and the rotors, which are highly susceptible to cavitation. To achieve a long life service under cavitation conditions, the pieces made of this steel are subjected to volumetric thermal treatments, which change the structure and mechanical properties. In this paper, one presents the results of the research concerning the behavior and the resistance to the cavitation erosion of the thermally sensitized GX5CrNi18-10 stainless steel, applying four different temperature regimes (two at 650°C and two at 750°C) and different durations (30 minutes and respectively 60 minutes). The results are presented in the form of cumulative mass loss curves M (t) and erosion rate v (t). The assessment of the cavitation resistance provided by each heat treatment regime is based on the average durability cavitation parameter, as defined by K. Steller. The research was conducted on the standard vibrator with piezo-ceramic crystals from the Cavitation Laboratory of the Politechnica University of Timisoara.

Оperational state of Myanmar cable-stayed bridge structures

The features of the Myanmar road network are briefly reviewed, the country’s bridge park, which includes about 500 bridges, is analyzed in more detail, examples of various types of bridge structures used in Myanmar (arched, hanging, frame, truss, adjustable, cable-stayed) are given. Particular attention is paid to cable-stayed bridges, data on their condition according to the results of surveys conducted jointly with Japanese specialists is given, characteristic defects and damage to the bridges are given, and the reasons for their appearance are indicated. It is noted that the average durability of Myanmar bridges is 30–35 years. In conclusion, the history of the construction of cable-stayed bridges in the USSR and Russia is briefly reviewed, the most famous cable-stayed bridges of Russia of various years of construction and their parameters are listed/ The disadvantages of cable-stayed bridges from the point of view of their resistance to wind loads are analyzed and it is shown that cable-stayed bridges with large spans have insufficient bearing capacity. The reasons for local and global cable-stayed bridge failures (physical, design, technological) are considered. It is concluded that in the case of large spans, suspension bridges have significant advantages over cable-stayed.

CALCULATION OF MULTI-BLADE CUTTING TOOL RELIABILITY

The process effectiveness of blade cutting is defined considerably with the prediction accuracy of cutting tool durability term. But, in spite of that cutting processes have a probabilistic character, in modern mechanical engineering there are used durability de-pendences describing only the dependence of an average period of blade cutting tool durability upon cutting modes without taking into account a stochastic nature of tool wear depending upon many factors. For ac-counting cutting process variability there are offered stochastic models of cutting tool failure, but they hold good for a cutting tool with one cutting edge and in the case with a multi-blade cutting tool they must be speci-fied. In the paper it is defined that at a fan wear model with the increase of the blade number the period of cutting tool durability decreases, as failure likelihood of even one blade increases because of the blade properties spread of one tool. The factor of a durability period variation decreases with the growth of the blade number because of the decrease of an average durability period decrease. In the case of a wear accumulation model the multi-blade tool reliability does not depend upon the blade number. The dependences of an average period of durability and a factor of variation at a complex model of wear are similar to the case with the fan model of wear, but their values will be higher. In the case of a destruction model the factor of multi-blade tool durability variation does not depend upon the blade number, but an average durability depends considerably upon the blade number, but the dependence appearance corresponds to the dependence of an average durability at a fan model of wear. The type of the dependence of durability average period upon on the blade number at a generalized model of failures is similar to the cases considered previously, and a kind of the dependence of a variation factor changes depending on model parameters