Scaling Law for Electrospray Droplet Formation

There has been a lot of research on liquid atomization by means of electrospray, particularly because of its many practical applications. Nevertheless, full understanding and control of the electrospray mechanisms are still incomplete. An experimental setup was developed in order to investigate the frequency characteristics of droplet formation and ejection at the tip of Taylor's cone of aqueous electrosprays. Droplet formation and oscillations were monitored using a Kodak Ektapro high-speed camera. The frequency of droplet formation at the tip of the capillary needle was analyzed. Droplet frequency formation appears to exhibit three distinct regimes with an abrupt transition from one regime to another. Droplet formation was recorded at different needle-plate electrode distances. Based on the analysis of experimental data a scaling law for droplet formation was found.     

Comparative Experimental Study of Triboelectric Charging of Two Size Classes of Granular Plastics

The free fall triboelectrostatic separation is widely used for the selective sorting of plastics from granular industrial waste. The electric charge per mass ratio of the granules is a critical parameter influencing the purity of recycled plastics and the efficiency of the electrostatic separation process. The aim of the present study is to validate an experimental procedure for the optimization of the vibratory-type tribocharging device for granular plastics. This tribocharger is composed of a metal plate covered with a thin PET (polyethylene terephthalate) layer. The amplitude of the vibratory motion of the plate can be adjusted using a potentiometer. The length of the vibratory feeder, the flow rate, and the velocity, at which the granules move on its surface, are the variables that can be controlled in order to optimize the tribocharging process. As particle size is an important physical factor influencing the charging process, the study was focused on two size classes (1 to 2 mm and 2 to 5 mm) of ABS (acrylonitrile butadiene styrene) granules originating from the recycling process of waste electrical and electronic equipment. The optimum operating conditions, obtained by using the response surface modeling methodology, differ between the two size classes of granules. Both the length of the vibratory tray and the velocity of the granules on its surface have a significant effect on the outcome of the tribocharging process.     

Investigating the implications of extending synchronized sequencing in automotive supply chains: the case of suppliers in the European automotive sector

In recent years automakers have paid considerable attention to synchronizing supply chain material flow. Potential benefits associated with synchronization include stability in both demand and supply patterns, inventory reduction, elimination of demand amplification and better long-term planning. In major European production sites, the geographic proximity of suppliers to the vehicle assembly plants provided the motivation for examining the feasibility of extending the synchronized sequenced delivery of components upstream in the vehicle supply chain. The value stream used in the research concerned the seating systems at two major European production sites. The results of extending synchronized sequencing from the first to the second tier showed a reduction in demand amplification to negligible levels, achieved overall synchronization levels of 99–100% and considerably reduced overall pipeline inventory between the vehicle assembly plant and the second tier component supplier. The findings suggest how the geographic proximity of suppliers can be used to implement multi tier synchronized sequencing of components to improve supply chain performance. Based on the results of the study a series of recommendations are provided concerning the supply chain implications of multi tier synchronized sequencing.     

含Mo和Ta作为β稳定剂元素的Ti合金在牙科应用中的电化学行为

研究具有相同Mo质量分数（12%）的Ti12Mo和Ti60Ta合金以及当前常用的Cp-Ti金属生物材料在牙科应用中的电化学行为。采用电化学方法,在37°C下,研究样品在人工唾液以及加氟人工唾液（含0.1%F-）两种电化学媒质中的电化学性能,如开路电位、动电位极化曲线和电化学阻抗。在牙膏、牙科凝胶和牙科冲洗等方面,通常含有氟化物以防止龋齿和缓解牙齿敏感。观察在两种媒质中所有钛合金样品的电化学行为,结果表明：在两种电化学媒质中,Ti60Ta合金具有比Ti12Mo和Cp-Ti更优异的抗腐蚀性能。     

Technological, Economic, and Environmental Optimization of Aluminum Recycling

The four strategic directions (referring to the entire life cycle of aluminum) are as follows: production, primary use, recycling, and reuse. Thus, in this work, the following are analyzed and optimized: reducing greenhouse gas emissions from aluminum production, increasing energy efficiency in aluminum production, maximizing used-product collection, recycling, and reusing. According to the energetic balance at the gaseous environment level, the conductive transfer model is also analyzed through the finished elements method. Several principles of modeling and optimization are presented and analyzed: the principle of analogy, the principle of concepts, and the principle of hierarchization. Based on these principles, an original diagram model is designed together with the corresponding logic diagram. This article also presents and analyzes the main benefits of aluminum recycling and reuse. Recycling and reuse of aluminum have the main advantage that it requires only about 5% of energy consumed to produce it from bauxite. The aluminum recycling and production process causes the emission of pollutants such as dioxides and furans, hydrogen chloride, and particulate matter. To control these emissions, aluminum recyclers are required to comply with the National Emission Standards for Hazardous Air Pollutants for Secondary Aluminum Production. The results of technological, economic, and ecological optimization of aluminum recycling are based on the criteria function’s evaluation in the modeling system.     

World fertilizer nutrient reserves: a view to the future

The increasing need for food production in subtropical regions likely translates to a need for additional plant nutrients. As a consequence, knowledge of world fertilizer nutrient reserves is of particular relevance to sustainable agriculture in the subtropics. The stewardship responsibilities of agriculture include the wise use of the raw materials from which commercial fertilizers are produced. Development and implementation of fertilizer best management practices with focus on the 4Rs-right source, right rate, right time, right place-are timely not only for short-term economic and environmental reasons, but also for the wise stewardship of the non-renewable nutrient resources upon which food, feed, fiber, and fuel production depend.     

ATLeS-SN

As wireless sensor network platforms become increasingly more complex to design and optimize due to the multitude of interdependent parameters that must be considered, computer simulations have emerged as the primary solution to feasibly analyze the long-term effects of design changes within a deployed system. Although several successful wireless sensor network simulators have already been developed, to our knowledge, none provide the modularity necessary to model sensor nodes and/or environmental components at differing levels of abstraction. In this paper, we present the Arizona Transaction-Level Simulator for Sensor Networks (ATLeS-SN), which by virtue of its implementation language—SystemC—allows application developers to easily specify interchangeable component models in order to achieve the desired simulation correctness, performance, and scalability. We provide an overview of our proposed simulation framework and highlight its benefits using a sound ranging application.     

The use of dihydrazides as latent curing agents in diglycidyl ether of bisphenol A coatings

Dihydrazides of different structure were synthesized and tested as curing agents for DGEBA epoxy coatings. By calorimetric studies their latent characteristics were proved and the kinetics of the curing studied. The temperatures of activation are usually dependant on the melting point of the dihydrazide. The acceleration by base and Lewis acids was proved, but the latent character was diminished. FTIR/ATR allowed characterizing the final structures of the thermosets and confirming that the fully cured was achieved. The thermal stability of the materials and their thermomechanical characteristics were evaluated by TGA and DMTA, respectively. Mechanical properties of the thermosets were also determined.     

Absorbance and fluorometric sensing with capillary wells microplates

Detection and readout from small volume assays in microplates are a challenge. The capillary wells microplate approach [Ng et al., Appl. Phys. Lett. 93, 174105 (2008)] offers strong advantages in small liquid volume management. An adapted design is described and shown here to be able to detect, in a nonimaging manner, fluorescence and absorbance assays minus the error often associated with meniscus forming at the air-liquid interface. The presence of bubbles in liquid samples residing in microplate wells can cause inaccuracies. Pipetting errors, if not adequately managed, can result in misleading data and wrong interpretations of assay results; particularly in the context of high throughput screening. We show that the adapted design is also able to detect for bubbles and pipetting errors during actual assay runs to ensure accuracy in screening.