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Petroleum Geophysical Survey
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
A variety of commercial gravimeters are available. The principle of working of the gravity determination apparatus is either of a ‘spring elongation’ or ‘pendulum oscillation time period’ under the influence of gravitational force. Again, spring elongations (extension) or the time period of pendulum oscillation is not measured in absolute terms. Only the initial and final meter readings (number) are recorded on an already calibrated instrument. Gravity variation or anomaly is estimated with the help of elongation or time period recorded by the instrument. Two types of gravimeters, based on the above-mentioned principle, are the spring elongation balance and the pendulum torsion instrument. A third type of gravimeter is based on the combination of these two features.
Geophysical investigation techniques: gravity
Published in Ian Acworth, Investigating Groundwater, 2019
The instruments used for gravity measurement are called gravity meters or gravimeters. Gravity can be measured in the time domain to investigate temporal changes in gravity or in the space domain by moving a gravimeter about the country. The most widely available is a spring balance system in which a spring supports a mass as shown in the basic form in Figure 10.2. It is important to protect the spring from damage and changes in heat. In the CG-5 system (Scintrex Autograv – Figure 10.3), the spring is contained within two ovens held at a constant temperature.
Physics of the Globe
Published in Aurèle Parriaux, Geology, 2018
Gravimetry is both a theoretical discipline in academic geology and a geophysical technique for resource exploration (groundwater, minerals, etc.). We will first examine the method in general, then the applications that involve engineering.
Facility for aerosol monitoring instruments (ManDust): design and fabrication of a versatile diffuser tower with isokinetic sampling probes
Published in Instrumentation Science & Technology, 2023
Giang Hoang Nguyen, Hanh Hong Thi Phan, Thang Toan Vu, Hoa Thi Tran, Tung Son Tran, Trung Quang Nguyen, Nam Thanh Duong
For a calibration facility to be reliable, it must address the pros and cons of the calibrated instrument. There are three types of aerosol monitoring instruments commonly used: (a) reference gravimetric, (b) optical particle counter, and (c) oscillating microbalance, each with their own advantages and disadvantages. The reference gravimetric method is the basis for many outdoor monitoring techniques. The accuracy of this system varies depending on the ambient conditions[15,16] and cannot display short-term patterns. Optical particle counter is the most portable of the three as it is designed to be handheld, wearable, and provide real-time data. As the instrument relies on the refractive index of the aerosol to calculate the concentration, only particles that have similar refractive indexes of that during calibration are accurately counted and classified.[17,18]
Geotechnical parameter assessment of sediment deposit: A case study in Pasakha, Bhutan
Published in Cogent Engineering, 2021
Karma Tempa, Nimesh Chettri, Raju Sarkar, Sunil Saha, Lily Gurung, Tshering Dendup, Bhawani Shankar Nirola
Specific gravity is the ratio of the weight of a given volume of material to the weight of an equal volume of water (at 20°C). The specific gravity indicates how much heavier (or lighter) the material is than water according to IS: 2720 (Part 3- section 2)-1980. Specific gravity is an integral gravimetric property useful for determining various soil properties such as the void ratio, unit weight, degree of saturation and most importantly the porosity of the soil. It can also be used in wet analysis for determining particle size. Thus, specific gravity of soil should be precisely determined. The Pycnometer method was adopted for determining specific gravity of soil for fraction passing 4.75 mm I. S. sieve and results are presented in Table 5.
Characteristics of soil micro-and macro-arthropods and soil properties in Songnen Grassland of China during different periods of freeze–thaw season
Published in Chemistry and Ecology, 2019
Baogen Feng, Jiahui Tao, Yue Zheng, Xu Wang, Ping Guo
The diagonal method was used to collect 1 kg of soil samples in each sampling plot to measure the soil physicochemical properties and material contents in three periods. Soil pH and electrical conductivity (EC) were determined using a combined electrode (Accumet, AccupHast, Fisher Scientific). Soil moisture content was measured by the gravimetric method. After fresh soil inorganic nitrogen was extracted using 2.0 M KCl, ammonium and nitrate nitrogen were measured by the indophnol-blue dual wavelength ultraviolet spectrophotometry [26]. SOM was measured by the potassium dichromate volumetric method [27]. Urease activity was determined by the method of Kandeler and Gerber [28]. Protease activity was determined by the method of Watanabe and Hayano [29]. Invertase activity was analysed by 3,5-dinitrosalicylic acid colorimetry [30].