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[en] Checking the quality of live steam is an essential prerequisite for a careful mode of operation of a saturated steam turbine. For this purpose a steam moisture measurement system has been developed and introduced into the nuclear industry. In this article, the principle of measurement, parameters of the steam moisture probe, electronic data processing, operating instructions, and economical advantages are briefly discussed
[en] The present study develops an environmental chamber for temperature and humidity control (THCS) in which the condenser is divided into two parts. By properly adjusting the fan speeds of the outer and inner condensers, an enclosed chamber can obtain net heating or cooling effect and the temperature and humidity can be directly controlled. The system dynamics of the THCS is first studied. The temperature response models, G 11(s) and G 12(s), are shown to be of a first order. The humidity response models, G 21(s) and G 22(s), are of second order with a zero. It is found that the multiple-input-multiple-output (MIMO) control system can be decoupled into a temperature and humidity control loops. A control system using a PI controller is designed and implemented on a PC with an 8051 microprocessor. It has experimentally been shown that the chamber temperature and humidity can be controlled to within ±0.1 deg. C and ±1% R.H., respectively. In the presence of a heat load disturbance, the controller can restore the THCS to operate at the setting values within a reasonable transient time
[en] Abstract Background: Relative humidity (RH) is one of the key environmental parameters in many experimental processes, and RH control is particularly important for in-situ synchrotron radiation experiments. However, there is no suitable commercial RH control equipment available for such experiments. Purpose: Based on the dynamic control of microcontroller, this study aims to develop an integrated set of numerically controlled (NC) RH control device, which can be conveniently loaded on the synchrotron radiation end-stations. Methods: A moisture channel and another dry air channel are connected to the sample chamber for humidification and dehumidification respectively. The dynamic equilibrium of RH at various values is controlled by the microcontroller using a fuzzy algorithm. Results: This device can hold the RH with an error of ± 1.0% at any set value from 20% to 94%. It also can increase the RH from 20% to 90% and decrease the RH from 90% to 20% with an error of ± 1.5% at a constant speed. Conclusion: This device can provide RH controlling environment with three switchable operation modes including RH holding, increasing and decreasing. It can meet various requirements of humidity control in kinds of synchrotron radiation in-situ experiments. (authors)
[en] Highlights: • Shrinkage of concrete is measured with various temperature and humidity conditions. • The fib MC2010 shrinkage model is accurate for low RH and high T conditions. • The fib MC2010 shrinkage model slightly underestimate for other conditions. • The fib MC2010 creep model conservatively predicts creep strains. - Abstract: Creep and shrinkage of concrete is influenced by many factors including relative humidity and temperature. The combined effect of low relative humidity (<20%) and high temperature (38 °C) on creep and shrinkage of concrete is uncertain as limited tests have been conducted in this domain. Also unknown is the ability of the fib MC2010 model code in predicting the shrinkage and creep at the environment. This paper presents the results of experiments conducted in which concrete was cast and exposed to the aforementioned environmental conditions. The shrinkage and creep behaviour of the concrete was observed for 110 days, and experimental results were compared with predicted values using fib MC2010 model code.
[en] A hydrophobic standard for calibrating radiation moisture gauges is described. This standard has little or no affinity for water and accordingly will not take up or give off water under ambient conditions of fluctuating humidity in such a manner as to change the hydrogen content presented to a nuclear gauge undergoing calibration. (O.T.)
[en] Laboratory methods (Greacen, 1981), as well as field methods (Watt and Jackson, 1981) for calibrating neutron moisture meters in stone-free soils have been described. None of these methods is practical in soils stony enough to prevent augering or repacking of the soil. This note describes a technique to calibrate neutron moisture meters in soils with stone content up to 60%. The slope of the relationship between neutron count ratio and soil water content of a neutron moisture meter varies by up to 10% for a range of Canterbury stony-soil types. This variation means that calibrations are site specific. The method of calibration is to measure the count ratio on an in situ soil and then to determine the volumetric moisture content of the measured soil.This is repeated over a range of soil moistures to derive a linear regression between soil moisture and count ratio
[en] Highlights: • A novel capacity controller for TEAC systems for improved indoor humidity control is developed. • The novel controller was developed by integrating two previous control algorithms. • Experimental controllability tests were carried out. • Improved control over indoor humidity levels and higher energy efficiency can be achieved. - Abstract: Using a multi-evaporator air conditioning (MEAC) system to correctly control indoor air temperatures only in a multi-room application is already a challenging and difficult task, let alone the control of both indoor air temperature and humidity. This is because in an MEAC system, a number of indoor units are connected to a common condensing unit. Hence, the interferences among operation parameters of different indoor units would make the desired control of an MEAC system hard to realize. Limited capacity control algorithms for MEAC systems have been developed, with most of them focusing only on the control of indoor air temperature, and no previous studies involving control of indoor air humidity using MEAC systems can be identified. In this paper, the development of a novel capacity controller for a three-evaporator air conditioning (TEAC) system for improved indoor air humidity control is reported. The novel controller was developed by integrating two previous control algorithms for a dual-evaporator air conditioning system for temperature control and for a single-evaporator air conditioning system for improved indoor humidity control. Experimental controllability tests were carried out and the controllability test results showed that, with the novel controller, improved control over indoor humidity levels and better energy efficiency for a TEAC system could be obtained as compared to the traditional On–Off controllers extensively used by MEAC systems.
[en] An Infra-Red camera has been used to reduce errors and to save time, cost and efforts for measurement of temperature distribution. Because allowable ranges of major factors that affect results of the measurement of the IR camera had not been established yet, this study has been performed to investigate the major factors and ranges for the effective measurement techniques. In this study, surface temperature, surrounding humidity, distance between the camera and the surface, incident angle, and emissivity of the surface have been considered as the major factors for the experimental setup. Especially, it has been observed that the results of the IR camera have been affected by the surface emissivity greatly.