Suo - Mires and peat vol. 34 no. 2 | 1983
Käytännöllinen vedenpinnan mittauslaite.
English title: An audible buzzer apparatus for indicating water-table levels.
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The paper describes an apparatus for indicating the water level in ground water wells. It gives a sound signal whenever water completes the electrical circuit between the two leads of the probe. It is inexpensive and easy to use. The level of the water surface indicated by a piezoelectric buzzer thus leaving the user free to observe the depth scale.
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Mannerkoski,
Sähköposti:
ei.tietoa@nn.oo
Termogravimetrian kaytto kiinteiden polttoaineiden tutkimuksissa. Osa VIII. Massan ja lampötilan nostonopeuden vaikutus kineettisten suureiden arvoihin.
English title: The usability of thermogravimetry in fuel research. Part VIII. The effect of mass and temperature rate on the values of kinetic quantities in the thermogravimetry.
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We have investigated the influence of the sample mass and the temperature rate on the values of thermogravimetric quantities.
The substances used were powdered willow dust and calcium oxalate, since willow dust represents a relatively homogenous natural material whereas calcium oxalate is a very common reference material in thermogravimetric studies.
The temperature rate was varied from 0.5 °C • min-1 up to 100 °C • min-1 and the masses were ranging from 10 mg to 420 mg.
It is a widely adapted impression that a relatively large masses (several hundred milligrams) and a slow temperature rate (optimum 3 °C • min-1 give the best experimental repetition and correct results.
We conclude, however, that the variation in sample masses and in temperature rate in this experiment had no significant influence on. the kinetic quantities computed.
The deviations originate from the differences in the instrumental technique and this assesses a requirement for the improved instrumentation before the mathematical relationships between various quantities can be established.
Furthermore, the neglible small effect of the reaction order on the kinetic quantities was observed. This was rather surprising, because it was only partly expected due to the formulation of the basic expressions.
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Tummavuori,
Sähköposti:
ei.tietoa@nn.oo
- Venäläinen, Sähköposti: ei.tietoa@nn.oo
- Nyrönen, Sähköposti: ei.tietoa@nn.oo
Havaintoja auraus- ja kaivuriojien mitoista ja kunnosta soilla.
English title: The size and condition of ditches made by ploughs and tractor diggers in drained peatlands.
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Changes in the dimensions of ditches made by heavy ploughs or tractor diggers were followed during a 15 yearperiod after digging. The material consists of 102 experimental ditches (each 20 m in length) dug using either the plough or tractor digger method on four main site types. The results showed that the diminishing of the ditch dimensions was not significantly affected by the digging method, but rather by depth, water content and humification of peat.
Vegetation completely covers the peat surfaces of ditches after 15 years. The worst hindrances for water movement are shrubs (Salix, Betula pubescens, B. nana), but also sedges (Carex rostrata) and mosses (Polytrichum) lower the efficiency of ditches. The cleaning of ditches made by either methods seems necessary approximately 20 years after digging.
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Timonen,
Sähköposti:
ei.tietoa@nn.oo
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