Time Evolution of the Droplet Size Distribution in Dropwise Condensation

Droplet growth processes during dropwise condensation are simulated with a help of computer. We focus on instantaneous and time-averaged characteristics of droplet size distributions. Based on simulation results, shift of a single peak from small to large size is a significant characteristic for the instantaneous distribution before the first departure. Once condensing surface was refreshed time and again by shedding droplets, then coexistence, shift and combination of multiple peaks is the dominant feature. This indicates that the instantaneous droplet size distribution highly depends on growth time and target area. The findings can explain why different distribution characteristics were reported in experiments. Different from the instantaneous distribution, time-averaged size distributions for coalesced droplets follow a power-law style due to a collaboration of coalescence events and re-nucleation behaviors. However, the size range for the power-law distributions were affected by nucleation density. This requires an appropriate usage of the empirical or fractal model to predict theoretically heat transfer rate of dropwise condensation. The present work provides a comprehensive understanding of the instantaneous and time-averaged characteristics of droplet size distributions.

Internet – the First Source of (dis)Information

The Internet is the first medium in which controlling the content has become difficult or even impossible. One of its reasons is the fact that the Internet users – who so far were only passive recipients of media messages – have gained the possibility to create and distribute their own messages. Thus, they have become active participants of the participatory culture, in which it is difficult to distinguish between professional and amateur content. The boundaries between private and public domains have become blurred. The distribution of forces shaping public opinion has changed, because the content comes from large media corporations and nonprofessional creators alike. The Internet message is characterized by instantaneous distribution, the ease of editing and modifying its content, and vagueness of authorship. These features make the Internet particularly susceptible to disinformation purposefully aimed at manipulating its users. The fact that every activity undertaken by the Internet users is recorded and analysed is also conducive to manipulation attempts, as the data obtained this way are used to shape their opinions and influence their decisions. The aim of the article is to undertake a discourse on information and disinformation on the Internet in the context of the development of new digital communication tools. The article provides the examples of information manipulation, which could happen only in such an interactive and multimedia medium as the Internet.

On the added mass in a viscous incompressible fluid

It is proved that at the same instantaneous distribution of the flow velocity of a viscous incompressible fluid, the forces acting on a body moving with acceleration differ from forces acting on the body moving with constant velocity by a vector, which is equal to the added masses tensor multiplied by the acceleration vector. The tensor of the added masses coincides with the tensor calculated for potential flows with the same geometry of the body and surrounding surfaces, and does not depend either on viscosity or on the distribution of vorticity in the flow space. While the force corresponding to the motion with constant velocity depends on the history of movement.

WHAT IT TAKES TO INNOVATE: THE EXPERIENCE OF PRODUCING AN ONLINE, REAL-TIME CASE STUDY

The case method can be classified as a type of experiential learning because students treat the problem in the case as if it were real and immediate. Until the Internet there was no practical way for cases to actually be real and immediate. The Internet makes possible instantaneous distribution of cases, and it makes possible their creation in real time. This article describes a recent attempt to use the Internet to bring business reality to business courses, and to facilitate communication among instructors, students, and the case company. It explores the challenges and difficulties involved in producing a new type of case study, and it assesses the feasibility of doing so on a regular basis. The goal of the author is to stimulate a dialog about how the Internet can be used to move forward all of our teaching methods, but especially the one that is prominent in schools of business: the case method.

Interactive Storytelling and Experiential Learning

The author looks at the recent drivers that have changed the ways authors and audiences share stories, first by looking at the landscape in art and entertainment, and then by analyzing how these drivers are affecting education. Inspired by his own work as a film and new media producer and his recent foray into educational media, the author isolates four different factors for consideration: (a) the falling price and rising accessibility of digital image acquisition, (b) the Internet as a cheap and instantaneous distribution platform, (c) the evolving ways in which audiences are accessing and consuming content, and (d) increased interactivity between storyteller and audience. By analyzing both the entertainment and education industries, the author predicts that storytelling—a dormant educational tool through much of the 20th century—will become a centerpiece of future educational models. Furthermore, he asserts that storytelling itself must radically change to accommodate this new discourse.

Skewness as measure of the invariance of instantaneous renormalized drop diameter distributions – Part 1: Convective vs. stratiform precipitation

We investigate the variability of the shape of the renormalized drop diameter instantaneous distribution using of the third order central moment: the skewness. Disdrometer data, collected at Darwin Australia, are considered either as whole or as divided in convective and stratiform precipitation intervals. We show that in all cases the distribution of the skewness is strongly peaked around 0.64. This allows to identify a most common distribution of renormalized drop diameters and two main variations, one with larger and one with smaller skewness. The distributions shapes are independent from the stratiform vs. convective classification.

Skewness as measure of the invariance of instantaneous renormalized drop diameter distributions – Part 1: Convective vs. stratiform precipitation

We investigate the variability of the instantaneous distribution shape of the renormalized drop diameter making use of the third order central moment: the skewness. Disdrometer data, collected at Darwin Australia, are considered either as whole or as divided in convective and stratiform precipitation intervals. We show that in all cases the distribution of the skewness is strongly peaked around 0.64. This allows to identify a most common distribution of renormalized drop diameters and two main variations, one with larger and one with smaller skewness. The distributions' shapes are independent from the stratiform vs. convective classification.

NON-UNIFORM MIXING OF QUANTUM WALK ON CYCLES

A classical lazy random walk on cycles is known to mix with the uniform distribution. In contrast, we show that a continuous-time quantum walk on cycles exhibits strong non-uniform mixing properties. First, we prove that the instantaneous distribution of a quantum walk on most even-length cycles is never uniform. More specifically, we prove that a quantum walk on a cycle Cnis not instantaneous uniform mixing, whenever n satisfies either: (a) n = 2u, for u ≥ 3; or (b) n = 2uq, for u ≥ 1 and q ≡ 3 (mod 4). Second, we prove that the average distribution of a quantum walk on any Abelian circulant graph is never uniform. As a corollary, the average distribution of a quantum walk on any standard circulant graph, such as the cycles, complete graphs, and even hypercubes, is never uniform. Nevertheless, we show that the average distribution of a quantum walk on the cycle Cnis O(1/n)-uniform.