Much previous research has established that perceived ease of use is an important factor influencing user acceptance and usage behavior of information technologies. However, very little research has been conducted to understand how that perception forms and changes over time. The current work presents and tests an anchoring and adjustment-based theoretical model of the determinants of system-specific perceived ease of use. The model proposes control (internal and external--conceptualized as computer self-efficacy and facilitating conditions, respectively), intrinsic motivation (conceptualized as computer playfulness), and emotion (conceptualized as computer anxiety) as anchors that determine early perceptions about the ease of use of a new system. With increasing experience, it is expected that system-specific perceived ease of use, while still anchored to the general beliefs regarding computers and computer use, will adjust to reflect objective usability, perceptions of external control specific to the new system environment, and system-specific perceived enjoyment. The proposed model was tested in three different organizations among 246 employees using three measurements taken over a three-month period. The proposed model was strongly supported at all points of measurement, and explained up to 60% of the variance in system-specific perceived ease of use, which is twice as much as our current understanding. Important theoretical and practical implications of these findings are discussed.

/pdf/determinants-of-perceived-ease-of-use-integrating-control-10opxseq0g.pdf

Determinants of Perceived Ease of Use: Integrating Control, Intrinsic Motivation, and Emotion into the Technology Acceptance Model

As they travel through space, some light beams rotate. Such light beams have angular momentum. There are two particularly important ways in which a light beam can rotate: if every polarization vector rotates, the light has spin; if the phase structure rotates, the light has orbital angular momentum (OAM), which can be many times greater than the spin. Only in the past 20 years has it been realized that beams carrying OAM, which have an optical vortex along the axis, can be easily made in the laboratory. These light beams are able to spin microscopic objects, give rise to rotational frequency shifts, create new forms of imaging systems, and behave within nonlinear material to give new insights into quantum optics.

/pdf/orbital-angular-momentum-origins-behavior-and-applications-1sv8qfuhrs.pdf

Orbital angular momentum: origins, behavior and applications

Researchers interested in emotion have long struggled with the problem of how to elicit emotional responses in the laboratory. In this article, we summarise five years of work to develop a set of films that reliably elicit each of eight emotional states (amusement, anger, contentment, disgust, fear, neutral, sadness, and surprise). After evaluating over 250 films, we showed selected film clips to an ethnically diverse sample of 494 English-speaking subjects. We then chose the two best films for each of the eight target emotions based on the intensity and discreteness of subjects' responses to each film. We found that our set of 16 films successfully elicited amusement, anger, contentment. disgust, sadness, surprise, a relatively neutral state, and, to a lesser extent, fear. We compare this set of films with another set recently described by Philippot (1993), and indicate that detailed instructions for creating our set of film stimuli will be provided on request.

Emotion elicitation using films

Pain interrupts and demands attention. The authors review evidence for how and why this interruption of attention is achieved. The interruptive function of pain depends on the relationship between pain-related characteristics (e.g., the threat value of pain) and the characteristics of the environmental demands (e.g., emotional arousal). A model of the interruptive function of pain is developed that holds that pain is selected for action from within complex affective and motivational environments to urge escape. The implications of this model for research and therapy are outlined with an emphasis on the redefinition of chronic pain as chronic interruption.

https://interruptions.net/literature/Eccleston-PB99.pdf

Pain demands attention: a cognitive-affective model of the interruptive function of pain.

Recent news coverage on pricing portrays the importance of price fairness. This article conceptually integrates the theoretical foundations of fairness perceptions and summarizes empirical findings on price fairness. The authors identify research issues and gaps in existing knowledge on buyers’ perceptions of price fairness. The article concludes with guidelines for managerial practice.

The Price Is Unfair! A Conceptual Framework of Price Fairness Perceptions

An experimental investigation

Experimental work on undercooling and structure of tin-lead droplets emulsified in oil is described. The droplets, predominantly in the size range of 10 to 20 microns, were cooled at rates (just before nucleation) ranging from about 0.1 to 1 million K/s. The higher cooling rates were obtained by a newly developed technique of quenching the emulsified droplets in a cold liquid. Measured undercoolings (at the lower cooling rates) ranged up to about 100 K. Structures obtained depend strongly on undercooling, cooling rate before and after nucleation, and alloy composition. Droplets containing up to 5 wt pct Pb were apparently single phase when undercooled and rapidly quenched. Droplets in the composition range of about 25-90 wt pct Pb solidified dendritically, even at the most rapid quench rates employed, apparently because these alloys undercooled only slightly before nucleation of the primary phase.

Solidification of highly undercooled Sn-Pb alloy droplets

Aluminum-iron alloys with Fe contents of up to 8 wt pct were rapidly quenched from the melt using the planar-flow melt-spinning technique. Microstructural changes that occur across the thickness of melt-spun ribbons were investigated as a function of initial melt composition and ribbon thickness. A transition exhibiting a dramatic change in the cell spacing from a microcellular to a coarse cellular region was observed for all the alloys examined. For a given alloy, the volume fraction of the microcellular region decreases significantly with increasing ribbon thickness. A theoretical explanation for the observed behavior is presented in which the heat flow and solidification characteristics are related to the undercooling achieved before the onset of nucleation.

Solidification and microstructure analysis of rapidly solidified melt-spun Al-Fe alloys

Synthesis of TiC particulates and their segregation during solidification inIn Situ processed AI-TiC composites

In recent years, metal-matrix composite (MMC) processing techniques have evolved, whereby the reinforcing particulates are formed in situ in a molten alloy, and the melt containing the dispersions is cast into an ingot for subsequent fabrication into wrought products. One such approach involves the formation of TiC particulates in aluminum alloy matrices via a gas-molten metal reaction. In this approach, a carbon-bearing gas is introduced into a molten Al-Ti alloy, allowing Ti in the melt to react with the carbon released from the injected gas to form TiC. The volume fraction and the size of TiC particles are important parameters which influence the mechanical properties of these composites. Although it is reasonably clear that the volume fraction of the TiC particles is basically determined by the initial content of the Ti content of the melt, given a continuous supply of carbon during processing, the mechanisms responsible for controlling the TiC particle size are unclear. This communication is intended to present some recent results which provide some insight into the formation mechanisms.

M. G. Chu

Papers

An experimental investigation

Solidification of highly undercooled Sn-Pb alloy droplets

Solidification and microstructure analysis of rapidly solidified melt-spun Al-Fe alloys

Synthesis of TiC particulates and their segregation during solidification inIn Situ processed AI-TiC composites

Mechanism of TiC formation in Al/TiC in situ metal-matrix composites