DRYINC RATES DURING HIGH TEMPERATURE DRYING OF YELLOW POPLAR

Experimental drying rates during high temperature drying of Yellow Poplar is analyzed to determine types of drying mechanism. Drying rate during the constant rate period and effective diffusivity during the falling rate periods were obtained at dryer temperatures ranging from 100°C to 150°C.

The drying curve shows three drying regimes: a constant-rate period, and two falling rate periods. The constant rate period, where the drying rate is a linear function of time, is controlled by the rate of heat transfer to the wood surface. Both falling rate periods show a drying rate which is a linear function of the square root of time. Floisture migration during the first falling rate is by simultaneous capillary action and liquid diffusion. while moisture'migration takes place by vapor diffusion during the second falling rate period. This occurs when the moisture content of the wood falls below the fiber saturation point. The effective diffusion coefficient during both periods is found to be constant.     

Subsynchronous resonance phenomena considering skin effects insolid iron rotor turbo-generators

The question of how the skin effects of the eddy current in the rotor of a synchronous generator influence the induction generation modes and the torsional interaction modes of the subsynchronous resonance (SSR) phenomena is addressed. The 3-D magnetic diffusion equation is solved in a round solid iron rotor to provide data for comparison and discussion purposes. The problem of representing skin depth, which is frequency dependent, in the time-domain stability analysis based on dx/dt=[A]x is examined     

Mediated transfer of attitudes.

Attitudes cannot only be acquired, but may also be transferred like verbal conditioned responses. This was shown by associating a nonsense syllable with the name of a tribe, then developing a favorable or unfavorable attitude towards the nonsense syllable and subsequently testing whether such an attitude had been transferred to the trible. 2 nonsen syllables and 2 names of tribes were chosen as stimuli in a counter-balanced, sensory preconditioning design, requiring 4 groups of 20 Ss. A notable feature was the use of probability learning during the conditioning period; the probability of occurrence of Good or Bad after a nonsense syllable being .85. Transfer, which was successful, was tested in 2 ways: by requiring Ss to choose 10 out of a mixed list of 20 favorable and unfavorable attributes for each tribe and by rating each tribe on a semantic differential scale of Good-Bad. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quasithermodynamic theory of He3 and He4 solutions

The conventional theory of nonideal solutions is modified on the basis of Gorter's hypothesis, and various properties of He³ and He⁴ solutions are investigated. The variation of -temperature with He³ concentration is explained adequately right up to the phase separation region. A comparison between the theoretical and experimental results for excess chemical potentials, excess entropy, and excess enthalpy is then carried out. In view of the recognized complex behavior of the solution in the region 1 to 2° K, the observed satisfactory agreement between theory and experiment may be regarded as a strong support for the assumptions made in our work.     

Assembly Lines with Overlapping Work Stations

Traditionally assembly line balancing problems have been examined under the assumption of serial work station design. Thus no pair of work stations could be simultaneously working on the same copy of a product. This paper presents two models for which this assumption is dropped. The algorithms developed for operational design of such assembly lines are presented along with sample problems to demonstrate the computational procedures and advantages of these models.     

铜引线键合中影响焊球硬度因素的研究

铜丝球焊由于其经济优势和优越的电气性能近来得到了普及,然而,在引线键合工艺中用铜丝取代金丝面临着一些技术上的挑战。多年来,IC芯片焊盘结构已经逐步适应了金丝球焊。铜在本质上比金硬度高,因此以铜线取代金线便引出了有关硬度的问题。研究了用25．4μm铜丝球焊中与键合机参数有关的铜焊球硬度特性。采用电子打火系统不同的电流和打火时间设置,用5％氢气和95％氮气组成的惰性保护气体形成了一个典型的25．4μm大小的铜焊球,研究了维氏硬度的焊球。用实验设计建立了第一和第二键合参数,进行了无空气焊球基本数据调整。通过改变电子打火系统参数。对硬度特性进行了进一步的测试。典型的键合球的大小和厚度的第一键合响应证实铜键合球的生产实力与电子打火系统的电流和打火时间有关．