Photograph of Albert Stein

Portrait of Stein at approximately 40 years old

Photograph of Robert Mitchell Milton

Portrait of Milton at approximately 50 years old

Healthy Babies, cover

Cover of Healthy Babies, a promotional pamphlet created by the Hygeia Nursing Bottle Company Inc., Buffalo, NY. By the 1920s many companies sold infant feeding products. This nipple on this bottle was rubber.Title supplied by cataloge

Healthy Babies, first page

The first two pages of Healthy Babies, a promotional pamphlet created by the Hygeia Nursing Bottle Company Inc., Buffalo, NY. The makers claim that this bottle contains “no pockets or grooves for lurking germs.”Title supplied by cataloge

The safety margin and perceived safety of pedestrians at unmarked roadway

Many pedestrians cross out of crosswalks (i.e., unmarked roadway) in developing countries, but researches about their safety are under reported. This study explored safety related factors and their casual relations at unmarked roadway. Videos of 254 pedestrians' crossing process were analyzed objectively on safety and evaluated subjectively on perceived safety. The two safety indexes are consistent on important factors, with higher running frequency reduce safety while bigger group size increase safety. The two factors had contrary effect on pedestrian speed, which is positively related with safety. Higher looking frequency before crossing also enhance safety, partly by reducing running frequency and increasing going backwards with its planning nature. Longer waiting time before crossing can facilitate this planning behavior while at the same time leads to bigger group size. Buses are safer than cars, but they are not perceived as safer. In situations where only some vehicles yield, yielding ones bring danger due to sight blocking of unyielding ones in adjacent lanes. These findings can be applied to the design of intelligent transportation systems and the education of drivers and pedestrians to improve safety. (C) 2011 Elsevier Ltd. All rights reserved

Aerosol cluster impact and break-up : II. Atomic and Cluster Scale Models.

Understanding the interaction of aerosol particle clusters/flocs with surfaces is an area of interest for a number of processes in chemical, pharmaceutical, and powder manufacturing as well as in steam-tube rupture in nuclear power plants. Developing predictive capabilities for these applications involves coupled phenomena on multiple length and timescales from the process macroscopic scale ({approx}1m) to the multi-cluster interaction scale (1mm-0.1m) to the single cluster scale ({approx}1000 - 10000 particles) to the particle scale (10nm-10{micro}m) interactions, and on down to the sub-particle, atomic scale interactions. The focus of this report is on the single cluster scale; although work directed toward developing better models of particle-particle interactions by considering sub-particle scale interactions and phenomena is also described. In particular, results of mesoscale (i.e., particle to single cluster scale) discrete element method (DEM) simulations for aerosol cluster impact with rigid walls are presented. The particle-particle interaction model is based on JKR adhesion theory and is implemented as an enhancement to the granular package in the LAMMPS code. The theory behind the model is outlined and preliminary results are shown. Additionally, as mentioned, results from atomistic classical molecular dynamics simulations are also described as a means of developing higher fidelity models of particle-particle interactions. Ultimately, the results from these and other studies at various scales must be collated to provide systems level models with accurate 'sub-grid' information for design, analysis and control of the underlying systems processes

The red-light running behavior of electric bike riders and cyclists at urban intersections in China: An observational study

Electric bikes and regular bicycles play an important role in the urban transportation system of China. Red-light running is a type of highly dangerous behavior of two-wheeled riders. The main purpose of this study was to investigate the rate, associated factors, and behavior characteristics of two-wheelers' red-light running in China. A field observational study was conducted using two synchronized video cameras at three signalized intersections in Beijing. A total of 451 two-wheelers facing a red light (222 e-bike riders and 229 cyclists) were observed and analyzed. The results showed that 56% of the two-wheelers crossed the intersection against a red light. Age was found to be a significant variable for predicting red-light runners, with the young and middle-aged riders being more likely than the old ones to run against a red light. The logistic regression analysis also indicated that the probability of a rider running a red light was higher when she or he was alone, when there were fewer riders waiting, and when there were riders already crossing on red. Further analysis of crossing behavior revealed that the majority of red-light running occurred in the early and late stages of a red-light cycle. Two-wheelers' crossing behavior was categorized into three distinct types: law-obeying (44%), risk-taking (31%) and opportunistic (25%). Males were more likely to act in a risk-taking manner than females, and so were the young and middle-aged riders than the old ones. These findings provide valuable insights in understanding two-wheelers' red-light running behaviors, and their implications in improving road safety were discussed. (C) 2011 Elsevier Ltd. All rights reserved

Impact of cathode evaporation on a free-burning arc

A free-burning, high-intensity argon arc at atmospheric pressure was modelled during the evaporation of copper from the cathode. The effect of cathode evaporation on the temperature, mass flow, current flow and Cu concentration was studied for the entire plasma region. The copper evaporates from the tip of the cathode with an evaporation rate of 1 mg s-1. The copper vapour in the cathode region has a velocity of 210 m s-1 with a mass concentration of above 90% within 0.5 mm from the arc axis. The vapour passes from the cathode toward the anode with a slight diffusion in the argon plasma. Higher temperatures and current densities were calculated in the core of the arc caused by the cathode evaporation