The measurements of autonomy and technology for task svstems design

Numerous experiments in job enlargement, direct worker participation and autonomous workgroups have been reported. However, little cumulative knowledge has been gained through a lack of conceptual and theoretical bases. Moreover, worker autonomy and technology, the major variables in those experiments either were measured by questioning workers and supervisors and are consequently modified by their perception, or were measured in a very broad fashion.

In the present work more objective and specific measures for technology and autonomy, which can link job design research and experiments with job design practice, were developed and validated. Automony and technology are of course multidimensional concepts. Relevant aspects for job design are derived from a model for task related decision making which shows that the degree of worker autonomy is contingent on task technology and worker characteristics.

Technology is measured by cycle time, task repetitiveness, task skill level, disturbance level of a task and the disruption potential of a task system, through observation. A distinction is made between autonomy in regulation, which keeps the process on target by counteracting disturbances and autonomy in control which specifies targets. Measures for both types of autonomy are developed. The measures of technology and autonomy were tested in a sample consisting of 411 work stations in industry and proved to be effective and efficient for job design purposes.     

Quantification of structural changes in acute inflammation by fractal dimension,angular second moment and correlation

The aim of the study was to examine alteration and possible application of fractal dimension, angular second moment, and correlation for quantification of structural changes in acutely inflamed tissue. Acute inflammation was induced by injection of turpentine oil into the right and left hind limb muscles of mice, whereas control animals received intramuscular saline injection. After 12 h, animals were anesthetised and treated muscles collected. The tissue was stained by hematoxylin and eosin, digital micrographs produced, enabling determination of fractal dimension of the cells, angular second moment and correlation of studied tissue. Histopathological analysis showed presence of inflammatory infiltrate and tissue damage in inflammatory group, whereas tissue structure in control group was preserved, devoid of inflammatory infiltrate. Fractal dimension of the cells, angular second moment and correlation of treated tissue in inflammatory group decreased in comparison to the control group. In this study, we were first to observe and report that fractal dimension of the cells, angular second moment, and correlation were reduced in acutely inflamed tissue, indicating loss of overall complexity of the cells in the tissue, the tissue uniformity and structure regularity. Fractal dimension, angular second moment and correlation could be useful methods for quantification of structural changes in acute inflammation.     

Response of real-time black carbon mass instruments to mini-CAST soot

Soot is a climate forcer and a dangerous air pollutant that has been increasingly regulated. In aviation, regulatory measurements of soot mass concentration in the exhaust of aircraft turbine engines are to be based on measurements of black carbon (BC) calibrated to elemental carbon (EC) content of diffusion flame soot. The calibration soot must currently meet only one criterion: minimum EC to total carbon (TC) ratio of 0.8. However, not including soot properties other than the EC/TC ratio may potentially lead to discrepancies between different BC measurements. We studied the response of two instruments, the AVL Micro-Soot Sensor (MSS) and the Artium Laser-Induced Incandescence 300 (LII), to soot from two miniature combustion aerosol standard (mini-CAST) burners. By changing the air-fuel ratio, premixing nitrogen into the fuel, and using a catalytic stripper to remove volatile compounds, we produced a wide range of particle morphologies and EC contents. As the EC content decreased, both the instruments underreported the EC mass, but the LII diverged more severely. Upon closer investigation of eight conditions with EC/TC > 0.8, the LII underreporting was found independent of primary particle size, but increased with decreasing geometric mean diameter of the soot agglomerates. As the geometric mean diameter decreased from 160 nm to 50 nm, the differences between the LII and MSS increased from 15% to 50%. The results suggest that in addition to EC content, calibration procedures for the regulatory BC measurements may need to take particle size distributions into account.

© 2016 American Association for Aerosol Research     

Synthese von 6-(pyrid-4-yl)-substituierten Pyrido[: 3-d]pyrimidinen und 1,8-Naphthyridinen

Synthesis of 6-(4-pyridinyI)-substituted Pyrido[2,3-d]pyrimidines and 1,8-Naphthyridinms A series of new 6-(4-pyridinyl)-substituted pyrido-[2,3-d]pyrimidines 2 – 4 and 1,8-naphthyridines 6 , respectively, is described. Cyclisation of 2-amino-5-(4-pyridinyl)-pyridinm-3-carboxamide 1a with diethyl oxalate gives the pyrido-[2,3-d]pyrimidinm 2a . Alkylation of( 2a ) yields the 3-ethylaminoxyrido[2,3-d]pyrimidine derivative 2b . Saponification of 2a , b gives the corresponding carboxylic acids 3a , b , which are decarboxylated by heating above the melting point to give 4a , b . The 2-amino-5-(4-pyridinyl)-pyridinm carboxylic acid derivatives 1 b – e react with ethylmalonylchloridm and diethyl malonate to afford the 1,8-naphthyridines 6b – e . The 1-oxide 7 in a similar reaction gives 8 and the oxdiazole( 9 ) which is converted by ring transformation to the 1,8-naphthyridine 10 .     

GEOSTATIONARY STATION-KEEPING BY ION THRUSTERS: GENETIC ALGORITHMS OPTIMIZATION

The orbital control of geostationary satellites requires the periodic execution of manoeuvres for gravitational and solar radiation perturbation compensation. To maintain a fine control of the satellite position, it is usually sufficient to perform orbit corrections every two weeks, firing chemical thrusters. The operational load for the manoeuvre's planning and execution is usually quite low. Innovative technologies for station-keeping are available now, based on high efficiency ion thrusters, which allow a significant propellant saving. They are included in Artemis, a telecommunications satellite developed by the European Space Agency. When low acceleration ion thrusters are adopted, a near continuous orbit control is required; the resulting long firing arcs can be in conflict with some operational or technical constraints. The station-keeping planning is a critical process, since it is not based on periodic impulsive manoeuvres, but rather on quasi-continuous firings. Furthermore the orbit control should be planned more on a seasonal or a yearly cycle rather than on short weekly cycles. Since each manoeuvre is defined by its start time and duration, the total number of parameters involved in a station-keeping optimization process amounts to several tens. The presence of many variables and logical constraints makes the use of classical optimization methods quite complex. The model proposed here is based on genetic algorithms, which allows the convergence to an optimum solution through successive iterations, in which a random set of solutions is progressively selected on the basis of a factor of merit tailored to the target. This paper presents some innovative concepts for station-keeping optimization when ion propulsion is adopted for orbital control; furthermore, the general properties of genetic algorithms are discussed, together with the results obtained in the specific station-keeping application.     

Bench-scale processing of amaranth seed for oil

Amaranth seed (Amaranthus hypochondriacus cv. K432) was processed to obtain oil, reported to be a promising source of squalene. The amaranth seed was ground using a stone mill, then separated into oil-rich embryonic tissue (or “bran”) and starchy perisperm. Amaranth bran was much more stable than rice bran when free fatty acid (FFA) content and peroxide value were monitored. Milling at a gap of 0.755 mm did not result in excessive damage to the starch in the perisperm fraction and yielded a bran fraction that contained more than three-fourths of the oil and a starchy fraction consisting of more than two-thirds of the seed weight. The bran particles were too fine for effective bench-scale extraction of the oil. Consequently the bran was extruded into collects prior to extraction. Two extrusion settings were evaluated regarding the rate of moisture injection, while the bran feed rates were constant. There was no significant difference in appearance or size between the two dried collets. Collets were extracted with hexane using an Armfield Extraction/Desolventizing Unit (Model FT 29, Armfield, Ltd., Hampshire, England). Oil recovery averaged 97.7 and 80.0%, respectively. Oil was extracted at high yield from the bran when the bran was extruded into collets. Oil can be obtained as a coproduct of amaranth starch by milling and separating the fractions of amaranth seed. Milling, extrusion, and extraction did not decrease significantly the squalene content in amaranth oil, but increased FFA content and peroxide value and changed tocopherol content of the oil.