Dependence of drop speed on nozzle diameter, viscosity and drive amplitude in drop-on-demand ink-jet printing

Results of recent experiments and numerical simulations are presented, which have been used to establish empirical rules for the dependence of drop speed on nozzle diameter and drive amplitude for Newtonian and non-Newtonian fluids printed with a range of different ink-jet print-head technologies. Experiments were carried out with Xaar, MicroFab and Spectra Dimatix print heads and with solutions of polystyrene in diethyl phthalate as model fluids. These results are compared with predictions from recent numerical codes developed by collaborators in the University of Leeds, and from simple models for drop-on-demand fluid jetting resulting from physical law

How PEDOT:PSS solutions produce satellite-free inkjets

This work is sponsored by EPSRC grant number RG5560

Strategies for Developing Responsive Solid Waste Management in Seoul City : Institutional Arrangement

The solid waste problem surfaced with the industrialization in 1960' s in Seoul City. Before that time the solid waste was merely a trivial issue so that divisions such as Police Bureau, Social Affairs Bureau, and Health and Sanitary Bureau in the Metropolitan Government, which seem rather irrelevant, used to handle solid wastes as well as night soil in addition to their major duties. Citizens used to practice complete recycling according to the Korean tradition until 1950' s. The economic development in the Republic of Korea was accomplished mainly in the manufacturing industry, which resulted in the movement of rural population to urban areas. In 1988, the urban population reached to 78 per cent of the national total from 20 per cent three decades before. And the population is so centralized to the Capital Area that one fourth of the national total population live in Seoul City and 40 per cent in the Capital Area which includes Incheon City and Kyungki Province which holds many satelite cities of Seoul. This urbanization together with the change in life pattern accompanied by the industrialization suddenly brought forth the solid waste problem. The solid waste generation reached to the level of 2.83 kg/capita-day, which is the world's largest, and the City spent 73 billion wons to dispose 11 million tons of wastes in 1989. Since the waste dumping is getting very difficult due to limited space available, the solid waste became one of the main urban problems the City faces at the moment

Social Environmental Education toward Sustainable Development in the East Asian Region

The East Asia with China and India included is the most populous region in the world and its economy is growing very fast to become the world's greatest economic center in near future. Because of the rapid economic development and the high economic density in this region, environmental stresses have built up very rapidly in recent years. The trans boundary air pollution, water shortage, drinking water poisoning, fresh water and marine pollution, deforestation, climatic disasters, and other environmental problems are becoming serious threats to the wellbeing of peoples in this densely populated region. In other word, the East Asia has not been going toward sustainable society. This is well indicated in the ESI(Environmental Sustainability Index) reported by the World Economic Forum in 2005. Most of the East Asian countries ranked the bottom: North Korea ranked 146th among 146 countries evaluated, Taiwan 145th, China 133rd, South Korea 122nd, and India 101st

Policy Responses Towards Improving Solid Waste Management Seoul City

The Seoul City has been the capital city of the nation for about 600 years. However, the City experienced rapid growth only in recent years. The Republic of Korea remained an agricultural country until early 1960s. The rapid industrialization began with the First 5-year Economic Development Plan which started in 1962. The Seoul City grew very rapidly with the success of industrialization. The population of the City increased from 3,471 thousand in 1965 to 10,287 thousand in 1988, which occupies 23.9 per cent of the national total population. The annual population increase rate of the City during the time was 5. 07 per cent while the national average was 1. 66 per cent. As results of rapid industrialization and urbanization, the City faced with serious urban problems such as housing, traffic congestion, environmental pollution, and others. Among them, the solid waste management issue emerged as one of the most urgent urban problems in the City. Traditionally, Korean people did not produce any wastes to be dumped collectively: all wastes were recycled in principle. Wastes were either fed to livestocks or were utilized as fertilizer. However, the citizens could no more practice recycling as the composition of wastes changed and the City became congested. The Metropolitan Government organized a department responsible for managing solid wastes only in early 1960s

Environmental Management in Korea: an Emerging Role for Industry

Two decades ago, environmental management was primarily a concern of public interest groups, public administrators, natural resources managers and lawyers. The corporation's environmental management program, if it existed, was a staff function, focusing on the politics, the legal, economic and technical requirements of regulatory law, and on governmental relations. Environmental management now extends its reach into many functions of the business corporation, from the Executive Office on down. Today. environmental management is intertwined with international trade and marketing issues. Throughout the developed world, corporations are designing corporate environmental management programs to measure up to international standards following promulgation of ISO 14000 in 1996 of final standards by the International Organization for Standardization. This paper briefly reviews some of the major environmental problems in Korea, and the significant. well-publicized initiatives recently taken by four major chaebols (conglomerates) in declaring new priorities and funding for environmental management throughout their companies. Finally. some conclusions are drawn and questions raised about how effective these corporate environmental management programs will be

State of Air Pollution and Policy Issues in Seoul, Republic of Korea

The Republic of Korea has experienced severe environmental problems including air pollution because of the rapid urbanization and industrialization during the last three decades. The government has taken various countermeasures in order to solve the air pollution problems. The efforts to reduce the levels of sulfur dioxide(SO₂) and total suspended particulates (TSP) have been quite successful while nitorogen oxides and ozone (O₃) are emerging as more serious threats to the urban atmospheric environment due to the ever-increasing automobiles. The spacio-temporal analyses of the air quality using the monitoring data for the last ten years clearly revealed that the air quality changed with the urban development and countermeasure policies adopted. Future policy recommendations are made based on th analyses. As shown in Figure 1. the annual average levels of SO₂, TSP and CO decreased by 62%, 65% and 44%, respectively, over the last decade (1984-1993), while the oxidants' level (analysed as O₃) showed 63% increase during the same period. The level of NO₂ showed a slight increase in recent years

Promoting Public Participation and Environmental Education in the Republic of Korea

The industrialization in the Republic of Korea began only in early 1960's. The economic development has been based mainly on the export-oriented heavy-chemical industries. The development has been quite successful. But at the same time it brought severe environmental pollution problems, especially in industrial areas. There have been continual disputes between industrial firms and inhabitants over damages on agricultural and fishery products and on human health. In some areas it was hard to find solution so that the disputes ended up as removing the whole population from the problem areas such as in Ulsan, Onsan, and Yeocheon. Tens of thousand natives had to give up their hometown and occupation, which caused a serious social problem. The Government began to realize the seriousness of the environmental problems, and the Office of Environment was established in 1980 which was raised to the Ministry of Environment in 1990. However, the quality of the environment has not been improved much in spite of the Governmental intervention. It is probably because the Governmental policies have not been strong enough to keep up with the rapid industrialization while the public were not allowed to protest against or participate in governmental policies until democratization in 1987

Utilisation of Municipal Waste Water in Aerobic Composting of Solid Organic Waste of Bhubaneswar City

Approximately 600 tons of solid organic wastes and a huge bulk of sewage water are generated in Bhubaneswar city, Orissa, India daily endangering the urban environment. Solid wastes in windrows with sewage water inoculum decomposed faster compared to cow dung slurry and plain water treated wastes. C:N and C:P ratios declined relatively faster in sewage water treated windrows than cow dung slurry and water treated windrows during the experimental period of 45 days. The results indicated that the Bhubaneswar Municipal sewage water would be successfully utilised in solid waste composting

Oscillations of aqueous PEDOT:PSS fluid droplets and the properties of complex fluids in drop-on-demand inkjet printing

Shear-thinning aqueous poly(3,4-ethylenedioxythiophene): poly(styrene sulphonate) (PEDOT:PSS) fluids were studied under the conditions of drop-on-demand inkjet printing. Ligament retraction caused oscillation of the resulting drops, from which values of surface tension and viscosity were derived. Effective viscosities of <4 mPa s at drop oscillation frequencies of 13–33 kHz were consistent with conventional high-frequency rheometry, with only a small possible contribution from viscoelasticity with a relaxation time of about 6 μs. Strong evidence was found that the viscosity, reduced by shear-thinning in the printhead nozzle, recovered as the drop formed. The low viscosity values measured for the drops in flight were associated with the strong oscillation induced by ligament retraction, while for a weakly perturbed drop the viscosity remained high. Surface tension values in the presence of surfactant were significantly higher than the equilibrium values, and consistent with the surface age of the drops. [Graphical abstract - see article]This work was supported by EPSRC and a consortium of industrial partners (EPSRC Grant no. EP/H018913/1: Innovation in industrial inkjet technology). The high-speed camera and high power flash lamp were provided by the EPSRC Engineering Instrument Pool and we thank Adrian Walker for his help.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.jnnfm.2015.05.00