7,850 research outputs found
The significance of wing end configuration in airfoil design for civil aviation aircraft
Lift-dependent induced drag in commercial aviation aircraft is discussed, with emphasis on the necessary compromises between wing and configuration modifications which better lift performance and the weight gains accompanying such modifications. Triangular, rectangular and elliptical configurations for wing ends are considered; attention is also given to airfoil designs incorporating winglets. Water tunnel tests of several configurations are reported. In addition, applications of wing and modifications to advanced technology commercial aviation aircraft and the Airbus A-300 are mentioned
The Aerodynamic Optimization of Wings at Subsonic Speeds and the Influence of Wingtip Design
Some of the objectives of modern aircraft development are related to the achievement of reduced fuel consumption and aircraft noise. This investigation is mainly concerned with the aerodynamic aspects of aircraft development, i.e., reduction of induced drag. New studies of wing design, and in particular wing tips, are considered. Induced drag is important since, in cruising flight, it accounts for approximately one-third of the entire drag for the aircraft, and one-half while climbing. A survey is presented for the wing geometries and wing tip designs studied, and theoretical investigations of different planar wings with systematically varied wing tip forms are conducted. Attention is also paid to a theoretical study of some planar and nonplanar wings and their comparison with experimental data
The 2009 social balance sheet
The impact of the economic recession on employment is reflected in the information gleaned from social balance sheets filed for the year 2009. Staff numbers were down by 1.2 p.c. compared with 31 December 2008, which is more than double the average annual decline. As evidence of the use that firms have made of the various flexibility instruments available to help reduce the volume of labour, part-time employment increased in 2009, at the expense of full-time jobs, mainly because of the shift from full-time work schedules towards shorter working hours. Job losses took a proportionally higher toll on men than on women, and manual workers have been affected more than employees or management staff. Large enterprises had to face more staff cuts than SMEs. Among the different branches of activity, job losses were the heaviest in industry, followed by the financial services and insurance sector. Some job creation was still observed in certain branches, including health and social work. Workers affected by temporary lay-offs for economic reasons and by the crisis measures remain on their employer’s staff register, which has tended to limit the drop in the number of workers in employment, while the volume of hours worked, which is directly influenced by these measures, felt considerably in 2009. Combined with this decline, the increase with 3.8 p.c. of the average hourly labour costs led to an increase in staff costs of barely half a percentage point. Despite a rise in the number of training firms, budgets for both formal and informal training were revised downwards in 2009. In all, firms devoted 1.63 p.c. of staff costs to training their workers, compared with 1.72 p.c. a year earlier, a contraction that reflects the pro-cyclical nature of this expenditure. By contrast, participation rates among workers were higher, except where informal training was concerned.employment, staff costs, training, working hours, employment contract, full-time, part-time, skills, temporary worker
The 2010 social balance sheet
The economic recovery which followed the Great Recession of 2008 was reflected in a 0.5 % average increase in the workforce according to the social balance sheets used for the analysis of the year 2010. That expansion gathered pace during the year to 1 %, pointing to the usual time lag between the revival of activity and the actual recruitment of new staff. The growth in the number of temporary workers was particularly strong, as was the rise in the number of agency staff. SMEs proved considerably more dynamic than large firms in terms of job creation. At regional level, the expansion of employment was stronger in Wallonia than in Brussels and Flanders. In Wallonia, almost all branches of activity contributed to the job creation, but the health and social work branch accounted for the largest share. In Brussels, it was mainly the information and communication branch and the health sector that supported the employment growth. In Flanders, the contraction of employment in trade and transport, information and communication, and especially industry was counterbalanced by the expansion in the health sector. In 2010, firms invested more in formal and informal training for their workers, who also participated in such training in greater numbers. Conversely, both the amount spent and the number of participants were in decline in the case of initial training (alternating study and work experience) – which remains marginal. Firms operating in more than one Region are considerably larger than the average and proportionately more numerous to report training activities in their social balance sheet. Moreover, there are evident differences in training policy between firms located exclusively in Brussels, Flanders or Wallonia. The health and social work branch, which has been growing steadily for a number of years, was analysed separately. Over half of the workers in this sector, of whom 80 % are female, work part-time. The percentage of temporary contracts is above the average, and substitution contracts account for a third of them. Conversely, agency work is less common. The level of staff costs varies considerably within this branch, while remaining below the average. Finally, workers in the health and social work branch have broad access to training, but the training provided is less expensive and of shorter duration than in other branches of activity.employment, health and social work, social balance sheet, staff costs, training, employment contract, full-time, part-time, temporary worker
The Europe 2020 strategy
The Europe 2020 strategy lays the foundations for “smart, sustainable and inclusive” growth for the decade to come. Alongside this, a three-pronged monitoring mechanism – incorporating fiscal, macroeconomic and thematic surveillance – has been put in place to coordinate and supervise policies. It is in the context of the thematic analysis that the commitments made by Member States in favour of the Europe 2020 strategy are examined and their progress measured. The national reform programmes filed each year with the European Commission effectively contain the conversion of the five key European targets – with regard to employment, innovation, education, sustainable development and social inclusion – into national objectives and also the steps that the countries are intending to implement in order to advance along these different paths. The new model of governance – still in progress – was implemented for the first time in 2011, during what has been named the European Semester. The impetus was provided by the Annual Growth Survey carried out in January by the European Commission, which served as a basis for the endorsement of the priorities for fiscal consolidation and structural reforms by the European Council meeting held in the spring. In April, the Member States compiled their national reform programme and their stability or convergence programme. The Commission examined them in May and the European Council approved specific recommendations to each country in June, with the aim of strengthening the cohesion of the national policies planned in the budgets that are to be adopted by Member Sates during the following months, referred to as the National Semester. The mobilisation of countries in favour of the Europe 2020 strategy is proving insufficient in a certain number of fields. As far as the labour market is concerned, assuming that the commitments made by the Member States are honoured, the European strategic target of arriving at an overall employment rate of 75 % by 2020 would not be achieved, since there would be a shortfall of at least 1 percentage point. In the field of research and innovation, the share of GDP taken up by gross domestic expenditure on R&D would remain below the 3 % targeted by the EU. With regard to energy, sharing the effort between the Member States should ensure the achievement of the objectives for reducing greenhouse gas emissions (by 20 % compared to the level of 1990) and raising the share of renewable energy (to reach 20 % of final consumption of energy in 2020) contained in the climate and energy package. Energy efficiency should in turn grow by 20 % within the EU ; however, the efforts set out in the national reform programmes are not directly comparable between the countries. The education targets aimed at lowering the school drop-out rate to a level below 10 % and increasing the share of persons between 30 and 34 years of age with tertiary education to at least 40 % would not be honoured either. Lastly, with regard to social cohesion, the Member States are free to choose their national objectives on the basis of the indicators that they deem most appropriate depending on their own situation, in order to make their contribution to the European target of reducing the number of persons at risk of poverty and/or social exclusion by at least 20 million between now and 2020.country recommendations, surveillance, EU 2020, European Semester, governance, integrated guidelines, national reform programme, national targets
A study of various synthetic routes to produce a halogen-labeled traction fluid
Several synthetic routes were studied for the synthesis of the compound 1, 1, 3-trimethyl-1, 3-dicyclohexyl-2 chloropropane. This halogen-labeled fluid would be of use in the study of high traction lubricants under elastohydrodynamic lubrication conditions using infrared emission spectroscopy. The synthetic routes included: dimerization of alpha-methylstyrene, methanol addition to alpha-methylstyrene, a Wittig reaction, and an organometallic approach. Because of steric hindrance and competing reactions, none of these routes were successful
Recent commodity price developments : causes and effects
In the past few years, constant price increases have attracted much attention to commodity markets. The nominal prices of oil and most metals reached record levels, and their real prices reached the highest level in many years. The recent price surge was due mainly to a strong increase in demand for commodities. This can be attributed to the strong economic growth of the past few years and to the integration of a substantial part of the world population into the global economy and international trade. The price increase was also partly the result of supply side developments, such as the scarcity of spare production and refining capacity. This made the oil price sensitive to every event that had a negative influence on the oil supply, such as the recurrent geopolitical tensions. In recent years, economic growth and inflation in the oil-importing countries have been fairly resistant to the sharp increase in commodity prices, largely thanks to the changes in the monetary policy framework in comparison to the seventies, structural changes in the developed countries, the effect of globalisation and the favourable economic environment. Financial markets expect oil prices to remain at high levels in the short- and medium term. Moreover, according to the International Energy Agency and other observers, high oil prices are also expected to persist in the long term. Metal prices are forecast to ease from their current high levels, mainly as a result of supply side flexibility, as extra capacity can be added quite quickly. In view of the major economic impact of oil prices and the increasing concern about the effect of energy consumption on climate change, the government has an important role in the energy debate. Over the last couple of years there have been some initiatives to establish a common European energy and climate policy.commodity markets, energy, metals, oil, OPEC.
The social balance sheet 2006
According to the 2006 social balance sheets of Belgian enterprises, employment on average increased by 1.3 p.c. between 2005 and 2006. It expanded mainly in small and medium-sized enterprises while remaining unchanged in large companies. Employment grew in all branches of activity except in industry. A marked rise was recorded in the number of part-time workers, too. Consequently, the part-time employment rate increased again, the rise being especially strong for the male workforce. Staff movements were larger than in 2005, but net recruitment fell to only half of the previous year’s level. A strong increase in the staff turnover rate was observed in some industrial branches. Hourly labour costs rose by an average of 3.1 p.c. between 2005 and 2006, to 33.1 euro. Their level differs significantly between enterprises according to their branch of activity and their size. Labour costs are higher in enterprises operating in several regions than in single-region firms. In the latter, hourly labour costs are weaker in Wallonia than in the two other regions. Performance in the field of training still fell well short of the targets of 1.9 p.c. in 2006 for the financial effort indicator and 50 p.c. by 2010 for the employee participation rate. The first indicator, that is, the training budget as a percentage of staff costs, was estimated at 1.2 p.c. in 2006. There was a further but small increase in the rate of employee participation in training : only 36.4 p.c. of workers had access to training in 2006. In Wallonia, the percentage of training firms is lower and the indicators calculated solely for training firms remain systematically weaker than in Brussels and Flanders. Finally, the Belgian results of the Continuing Vocational Training Survey (CVTS) for 2005 were compared with those of the social balance sheets. The proportion of training firms is far higher in CVTS, probably because of the intensive follow-up provided to firms involved in the survey. On the other hand, the worker participation rate and the time spent on training as a percentage of working hours are similar in both statistics. As for the financial effort indicator, the results are very different, respectively 1.6 p.c. in CVTS and 1.3 p.c. in the social balance sheets, while they were quite similar in 1999 when the previous survey was carried out.employment, staff costs, training, working hours, employment contract, full-time, part-time, skills, temporary worker
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