[en] Preliminary data for the calibration of a neutron probe in deep alluvial soils for determining the humidity are reported. Comparisons of Neutron flow behaviour with the depth of the land are established. A characteristic curve of amount of detected neutrons according to the humidity percentage (from 50 to 100 % of the field humidity) is obtained

[en] After a brief summary of the applications and merits of portable nucleonic gauges in measuring the moisture content and density of soils, the theory and practice of the techniques involved is reviewed. Particular attention is paid to the proper methods to be employed in calibration and use of these instruments, and due emphasis is given to the practical and theoretical limitations of the techniques. (author)

[en] This study was carried out during the period from June 1995 to November 1996 supported by the International Atomic Energy Agency (IAEA) jointly with the Direction General de Energia Nuclear (DGEN) through the Agricultural Section. The objectives consisted on evaluating the effect of the incorporation of the organic residues of Bean (Phascolus vulgaris L.), MUCUNA (STIZOLOBIUM PRURITUM L.), vicia (Vicia sativa L.) and the stubble of maiz (Zea mays L.) all these compared with a witness in the yield of corn grain of the variety Don Marshall, expressed in kg/ha; to determine the calibration curve of the moisture gauge CPN 503 for the soils of Tecp ; to determine the indexes of consumption of moisture (kc) of corn and lastly to determine the soil moisture contents during the corn cultivation cycle (rainy season) and the beginning of the dry period. The response variables were: Content surface moisture (%), yield grain of corn (kg/ha), real evapotranspiration (Etr). The different valued treatments were: Witness (TO), stubble corn (B), bean (C), Mucuna (D) and Vicia (E); set up in an experimental design of random blocks with 4 repetitions. The moisture contents were determined by means of the use of the moisture gauge, taking in consideration the obtained calibration curve for each stratum, with the purpose to transform the gravimetric humidity in volumetric humidity, being obtained the higher values for the stratum 0-20 cm where the corn stubble was incorporated (B) with 20.11% and for the stratum 20-40 cm the best treatment it was where the organic residual of Vicia was incorporated measuring values of moisture of 25.97%. With regard to the yield corn of the variety Don Marshall (kg/ha), the best treatment was where the residual of Vicia was incorporated with a yield 4,595.13 kg/ha. The pluvial precipitation (PP) and evapotranspiration (ETP) during the cultivation cycle was 1,014.1 mm and 708.14 mm respectively. The values of moisture consumption indexes gives (kc) for the different fenological phases were: 0.982 in the vegetative phase, 1.076 in the phase of stigma formation, 0.902 in floraci, 0.973 during the crop formation, 0.733 in the phase of the grain maturation and 0.825 at the end of cultivation cycle (harvests)

[en] The correction factor on the density of soil at the determination of its moisture by neutron moisture gauges, which was proposed by authors, is experimentally confirmed. The correction factor makes it possible to construct the common graduate relation for the whole range of possible changes of the soil density. The use of the correction factor simplifies the interpretation of the readings of neutron moisture gauges.

[en] The measurement of water content in many materials by neutron is studied. The measurement has advantages of easy operation, speedy reaction with high sensitivity for continuous situ measurement

No abstract available

[en] The moisture content in the soil can be measured by a number of methods such as gravimetric (the primary method), TDR, soil moisture probe and neutron moderation. The aim of this paper is to obtain the moisture calibration curve using Neutron Moisture Gauge. In this study, the gravimetric method is used to measure soil moisture content directly. This data is used as a standard for the construction of calibration curve for the indirect methods such as neutron moderation. This calibration graph can be use to measure soil moisture content in-situ in the field by the neutron moisture gauge without soil samples taken for further laboratory analysis. (Author)

[en] The application of nuclear technique in civil engineering sector which emphasises on the in-situ density and moisture measurements of soil in road construction is discussed. The nuclear density-moisture gauge utilises both gamma-rays and neutrons for the determination of the density and moisture content, respectively. The knowledge on the density and moisture content will be used to evaluate the degree of compaction of the compacted layers. The technique offers not only a fast and non-destructive measurement but it is also accurate, economical and repeatable. A calibration equation which is stored in the built-in microprocessor is applicable for any type of soil. Corrections for the interferences from needless gamma-rays produced as a result of thermal neutrons interaction with certain nuclei for the density measurement and effects of hydrogen other than absorbed water for the moisture measurement are considered in the equation. This paper describes briefly the theory and the characteristics of the nuclear gauge and its application in road construction work

[en] Today thermal and mechanical properties are well-measured with common sensors like respectively PT100 sensors and vibrating wire sensors or new sensors like optical fiber sensors. On the other hand there is no reference sensor for the measurement of the concrete moisture. In this paper, we present our laboratory evaluation's protocol and first result for four different technologies of concrete moisture sensor based on our owner requirement. Specimens of porous mortar (E/C ∼ 0.8) with embedded sensor are placed into a temperature and humidity controlled climatic chamber. Then, different air relative humidity steps are enforced. Before each relative humidity change, stabilization of the mass of specimens is expected. The four technologies are based on: 1) capacity between two electrodes. The sensor is embedded in a porous Teflon cap. The sensor measures the humidity of air at equilibrium with concrete. Today it is the most common moisture sensor; 2) Elongation measurement of a calibrated nano porous material with a vibrating wire sensor. The sensor measures the hygroscopic volume change related to the humidity of the surrounding concrete. This sensor called Hydravib has been developed by Cementys S.A.S.; 3) Time Domain Reflectometry (TDR). The sensor measures an Electro Magnetic Wave time propagation in the concrete and this one is a function of the concrete permittivity; 4) gas permeability measurement of the ambient concrete. The sensor measures a pressure drop through a porous stainless filter. This study evaluates the capacities of four sensor technologies to indirectly measure one key parameter of concrete structure: the moisture concrete. Capacitive sensor does not seem to fulfill our requirements. Hydravib presents sensitivity to the moisture concrete evolution but it needs more development and a nano porous material calibration. Finally TDR and Pulse sensors present very promising results

[en] Equipment for direct soil water content measurements varies widely, and is available from many manufacturers. Ordinarily such equipment consists of devices for taking soil samples, devices for determining the volume of soil excavated (if volume is not determined directly by using a volumetric sampling device), containers for retaining and transporting the samples without loss of water, ovens for drying the samples, and scales for weighing the samples. Sampling equipment for mass basis water contents (θ_m, g g^-1) may be as simple as a shovel, scoop or tube to be thrust into the soil. Since volume is not a consideration for θ_m, the exact volume of the sampling equipment is not a concern, nor is any sample compaction or dilation. Equipment for volumetric water content (θ_v, m³ m^-3) determination is of known dimensions, and typically consists of tubes or cylinders with a bevelled cutting edge to ease insertion of the sampler into the soil. There are many different samplers, each with its own advantages and disadvantages