Design study: A 186 kW lightweight diesel aircraft engine

The design of an aircraft engine capable of developing 186 kW shaft power at a 7620 m altitude is described. The 186 kW design takes into account expected new developments in aircraft designs resulting in a reassessment of the power requirements at the cruise mode operation. Based on the results of this analysis a three phase technology development program is projected resulting in production dates of 1985, 1992, and 2000

Particle growth of nano-silica below the isoelectric point

Nano-silica is one of the most used nano-materials, and its use is rising 5.6% per year to reach a projected 2.8 million metric tons in 2016 with a value of $6.4 billion. The current production methods involve steps with high temperatures resulting in environmentally unfriendly and expensive process. The production of nano-silica by the dissolution of olivine is an interesting alternative to the existing commercial methods because of the good quality of the resulting silica and low energy requirements and CO2 emissions. Olivine nano-silica is produced in a very acidic environment, much more acidic than its isoelectric point. The particle growth of silica under these acidic conditions has only been studied by a few researchers. The main aim of this study is to clarify the mechanism and kinetics of the silica particle growth under these conditions. The silica particle growth was studied with Norwegian olivine in a vigorously stirred reactor at 20 °C with sulfuric acid. The concentration of hydrogen ions was determined at regular time intervals, from which the amount of silica produced was calculated. The silica particle size was measured with the Malvern ZS after passing the samples through a filter of 1 ¿m. The cluster size of olivine silica grows up to 420 nm after 4300 minutes of reaction at 20 ¿C in 2M H2SO4 solution. The mechanism of the growth of silica is likely due to the nucleation of primary particles and subsequent aggregation of these primary particles. Olivine nano-silica does not gel. This behaviour can be due to three reasons: 1) silica polymerizes fast at 90 ¿C in 3M H2SO4 solution, forming particles above 100 nm in a short time; 2) the concentration of small silica colloids is low; and 3) the vigorous mixing in the reactor to keep the olivine particles suspended

Particle growth of nano-silica below the isoelectric point

Nano-silica is one of the most used nano-materials, and its use is rising 5.6% per year to reach a projected 2.8 million metric tons in 2016 with a value of $6.4 billion. The current production methods involve steps with high temperatures resulting in environmentally unfriendly and expensive process. The production of nano-silica by the dissolution of olivine is an interesting alternative to the existing commercial methods because of the good quality of the resulting silica and low energy requirements and CO2 emissions. Olivine nano-silica is produced in a very acidic environment, much more acidic than its isoelectric point. The particle growth of silica under these acidic conditions has only been studied by a few researchers. The main aim of this study is to clarify the mechanism and kinetics of the silica particle growth under these conditions. The silica particle growth was studied with Norwegian olivine in a vigorously stirred reactor at 20 °C with sulfuric acid. The concentration of hydrogen ions was determined at regular time intervals, from which the amount of silica produced was calculated. The silica particle size was measured with the Malvern ZS after passing the samples through a filter of 1 ¿m. The cluster size of olivine silica grows up to 420 nm after 4300 minutes of reaction at 20 ¿C in 2M H2SO4 solution. The mechanism of the growth of silica is likely due to the nucleation of primary particles and subsequent aggregation of these primary particles. Olivine nano-silica does not gel. This behaviour can be due to three reasons: 1) silica polymerizes fast at 90 ¿C in 3M H2SO4 solution, forming particles above 100 nm in a short time; 2) the concentration of small silica colloids is low; and 3) the vigorous mixing in the reactor to keep the olivine particles suspended

Development of the particle and pore structure of silica below the isoelectric point

Nano-silica is one of the most used nano-materials, and its use is rising 5.6% per year to reach a projected 2.8 million metric tons in 2016 with a value of $6.4 billion. The current production methods involve steps with high temperatures resulting in environmentally unfriendly and expensive process. The production of nano-silica by the dissolution of olivine is an interesting alternative to the existing commercial methods because of the good quality of the resulting silica and low energy requirements and CO2 emissions. Olivine nano-silica is produced in a very acidic environment, much more acidic than the isoelectric point of the silica. The particle and pore structure development of silica under these acidic conditions has only been studied by a few researchers. The main aim of this study is to develop a model about the particle and pore formation of silica in very acidic environments. Nano-silicas prepared via the olivine route were analyzed to determine their pore structure and SSANMR. The pore structure was determined using the nitrogen physisorption, NMR and PALS (positron annihilation spectroscopy) techniques. The development of the nano-silica structure during the olivine process can be described by the following steps: 1) initially, soluble silica nucleates and primary particles of around 2 nm are formed; 2) the silica particles grow via a condensation route, forming linear chains; 3) as the growth continues, the silica particles keep increasing in size, resulting in 3D networks; and 4) with time, the aggregates become bigger and more compact. The final result of the olivine process is agglomerates as big as 20 ¿m. In addition, internal pores (also called closed pores) are developed with the reaction conversion degree as the result of condensation of two blocks of silica particles

Horizons in extension

INTRODUCTION Over 10% of the research capacity of the Eindhoven University is directed towards the field of Biomedical and Health-Care Technology. Being a University of Technology this covers activities in which technical knowledge and skills are applied to problems in health-care and biology. These activities are multidisciplinary in nature an therefore require cooperation between a variety of medical and technical scientists, medical clinicians, and Medical Technology (MT)-Industries. Development, selection and management of projects in these fields must include an attention for ethical, economical, organizational, and political aspects as well. A multidisciplinary project is directed towards a synergetical combination of several sources of knowledge, skills and information. Dealing with these combining activities over a time span of 15 years has proved to be a very demanding task. Furthermore it always requires good insight in the main characteristics of these contributing sources, and a judgement about their possibilities, as well as their impossibilities. Structuring communication processes in multidisciplinary set ups, towards common goals, requires attention to the specific areas as well as the finite "horizons" of the participating experts and parties concerned. Extension processes have to be included beyond these "horizons", carefully designed and guided during the entire progress of such a multidisciplinary project. The theoretical structure for Knowledge and Information Systems (KIS) of the Extension Science Department of the Wageningen University (Niels Roling et all 1989 [1]) provides a workable set up for the exchange of ideas and experiences on this topic. This paper focusses on the formulation of some generalities for extension in multidisciplinary activities and aims to project these on this theoretical framework, here referred to as N-KIS. MARKET-IN Generality 1 The effective management of knowledge and information is increasingly important for the continuity of organisations. However for many small organisations and for small industries in particular this is already becoming to difficult. The line of thoughts in the paper has to start by stressing the importance of KISmanagement as expressed in this statement. The knowledge transfer from university to (MT) industry is discussed briefly as a first case of extension activity. In doing so some marketing concepts are presented. Considering the need of small industries, as stated above, a University of Technology has much to offer. The university can provide knowledge products for a market consisting of industrial companies. In industry and trade it is well known that the continuity in the long run requires a strong "market-in" orientation, meaning that products must be developed that fit to real needs in the market and are based on careful research with respect to that. This truism, however, is often neglected and instead a so called "product-out" orientation is governing the product development policy, i.e. an attitude with a too strong belief in the product and a too strong disregard for the real needs of the market. Generality 2 University knowledge centres usually have a "product-out" orientation, and this has to change to a more "market-in" approach. The N-KIS-theoretical structure of Wageningen stresses a strong need for more "upstream" influence instead of a too dominant focus on "downstream" transfer of "on-the-shelf' knowledge products. This aspect of the N-KIS framework can not be stressed enough. Generality 2 expresses the same aspect using other concepts. Facilitating this upstream influence in the case University -(MT) Industry is initially taken care of by field research. Such a field exploration provides an example of market characterization for products of a knowledge centre. Since much of this approach may be projected on other fields, as well, the main findings are given in short terms The need for more knowledge in small industries (generality 1) was found to exist in the following topics, that are all generalities in themselves: -Increasing knowledge contents of products. -Increasing responsibilities for the products, which requires increasing care for product qualities. -Increasing costs of product development. -Faster obsolesence of production systems. -Reducing life cycles of products, causing the necessity of a higher rate of product innovations. -Reducing space for unsuccessful product innovations. -More care for the environment in solutions for technological problems. 3 -Increasing need for effective management in a strategic perspective Le. over longer periods and over a broad spectrum of product-market-technology combinations. In this survey of (MT)-industry characteristics were found affecting the capabilities for extending the knowledge and information system: -The finite capacity of the management and the large workload for mostly one, or a few persons, bearing the continuity of a small industry. -A dominating "short-term-orientation" caused by the necessity to fulfill short term goals continuously. -Specific knowledge, stored in a few persons, who also have a finite knowledge horizon, leading to weaknesses within the broadening spectrum of relevant knowledge on which the KIS of such a small industry should grow. -Limited financial means. A market for knowledge products has to be known very well for processes of knowledge transfer, even in much extended details as presented in this case. In order to enhance "upstream" effects substantially, a lot more has to be achieved. In most cases this is not realizable without compatible intermediaries. INTERMEDIARlES In the Wageningen theoretical frame work (N-KIS) much attention is given to the so called interfaces and linkage mechanisms. For example in most situations the "cultural distance" between research groups and target groups for extension is too big to bridge without such interfaces, Le. intermediaries. In the theoretical structure of the N-KIS this is believed to be one of the most important items. Moreover it provides a practical approach to the design of knowledge and information systems. Fig. 1 Good decision making regarding medical technology requires effective interactions between these domains In general more than two domains are involved in multidisciplinary projects. In the field of Medical Technology there always exist interactions between three general domains: Health-Care, Industry, University (see 4 Such a multidisciplinary project usually cannot function without effective intermediaries. It mostly needs a powerful "system integrator". The management or coordination of such a project must facilitate mutual extension processes. A joint KIS has to be built up around the goals of the project and incentives of the parties involved should be projected on the general aim of the project. Real cooperation only works when all participants are gaining enough to make it worthwhile to invest all the required extra effort in multidisciplinary set ups. An important finding in this respect is that this includes also the "system integrator" sometimes referred to as "system moderator". The fulfillment of the function of system integrator must be made beneficial, economical or otherwise. Generality 3 In designing a KIS the intermediaries do form key elements (as pointed out in the theoretical framework of Wageningen); each lOS needs a powerful "system integrator", mostly being the intermediary (or one of them); the function of "system integrator" has to be rewarding in itself. TIME HORIZONS The life cycle of any distinguished medical technology is presented i

Lightweight diesel engine designs for commuter type aircraft

Conceptual designs and performance of advanced technology lightweight diesel engines, suitable for commuter type aircraft power plants are defined. Two engines are discussed, a 1491 kW (2000 SHP) eight-cylinder engine and a 895 kW (1200 SHP) six-cylinder engine. High performance and related advanced technologies are proposed such as insulated cylinders, very high injection pressures and high compressor and turbine efficiencies. The description of each engine includes concept drawings, a performance analysis, and weight data. Fuel flow data are given for full and partial power up to 7620m altitude. The performance data are also extrapolated over a power range from 671 kW(900SHP) to 1864 kW (2500 SHP). The specific fuel consumption of the 1491 kW (2000 SHP) engine is 182 g/hWh (.299 lb/HPh) at cruise altitude, its weight 620 kg (1365 lb.) and specific weight .415 kg/kW (.683 lb/HP). The specific fuel consumption of the 895 kW (1200 SHP) engine is 187 g/hWh (.308 lb/HPh) at cruise altitude, its weight 465 kg (1025 lb.) and specific weight .520 kg/kW (.854 lb/HP)

A 150 and 300 kW lightweight diesel aircraft engine design study

The diesel engine was reinvestigated as an aircraft powerplant through design study conducted to arrive at engine configurations and applicable advanced technologies. Two engines are discussed, a 300 kW six-cylinder engine for twin engine general aviation aircraft and a 150 kW four-cylinder engine for single engine aircraft. Descriptions of each engine include concept drawings, a performance analysis, stress and weight data, and a cost study. This information was used to develop two airplane concepts, a six-place twin and a four-place single engine aircraft. The aircraft study consists of installation drawings, computer generated performance data, aircraft operating costs, and drawings of the resulting airplanes. The performance data show a vast improvement over current gasoline-powered aircraft

Constructive thinking and burnout among secondary school teachers

research articleThe present study investigated the relationship between Epstein’s (1998, Constructive thinking: The key to emotional intelligence. London: Praeger publisher.) components of constructive thinking and burnout as experienced by a sample of Dutch secondary school teachers. A postal questionnaire was sent to teachers from randomly selected secondary schools. The response rate was 54.1% (N = 433). Four components of constructive thinking significantly contributed to the explained variance in emotional exhaustion (17%), depersonalization (21%), and personal accomplishment (20%). The results of the study suggest that secondary school teachers’ maladaptive thinking processes prevent them from rational thinking during their work, which significantly contributes to the onset of burnout. Burnout intervention programs for teachers are likely to be more effective when the participator’s maladaptive thinking system is taken into consideration. This stems from the idea that personality factors are a probably easier point of departure to tackle burnout symptoms than organizational factors