China
Africa
Explore chapters and articles related to this topic
Drying of Agro Products
Published in B. K. Bala, Agro-Product Processing Technology, 2020
There are two general methods for determining the static equilibrium moisture content: (1) static method and (2) dynamic method. In the static method, the grain is allowed to come to equilibrium in still and moist air. Saturated salt or acid solution is normally used to maintain the relative humidity in this method. The dynamic method is quicker but complicated in design and instrumentation. In the dynamic method, the air is mechanically moved around the sample in a closed chamber containing a dew point apparatus or in a closed chamber containing either salt or acid solution. It is also important to measure moisture content as accurately as determining and maintaining relative humidity in the closed chamber. The dew point method is extensively used in the UK, whereas the chemical method of known relative humidity maintained by a saturated salt solution or acid solution is extensively used in the USA (static method).
Time Management
Published in Yan Tan, Large-Scale Construction Project Management, 2020
According to the point of time, which determines the impact of the delay, the analysis can be classified as prospective analysis which is undertaken prior to the delay event occurring and retrospective analysis which is performed after the delay event. The retrospective analysis can then be classified into the observation method and the modeling method. The observation method relies on the available programme, including baseline programme, As-Built programme and progress programme. While the static method simply compares the As-Planned programme with the As-Built programme the dynamic method involves comparing the programme change on a period by period basis. Unlike the observation approach, which merely reviews the programme, the model approach analyzes the programme activity in detail, and may add additional activity to demonstrate the delay events or subtract certain activities to investigate different scenarios. The additive model is based on a single baseline programme to add multiple delay events to analyze the impact as per the Impacted As-Planned analysis, or simulate with different scenarios as some window analyses do.
A novel approach for estimation of dynamic from static origin–destination matrices
Published in Transportation Letters, 2019
The proposed approach to estimate dynamic O–Ds entails subtracting the vehicles en-route from the next time interval static O–D matrix. In that sense, with a longer updating time interval, the average rate of uncompleted trips during one interval will be lower. At that point, the static O–D matrix computed by QueensOD will be rarelychanged by the dynamic method, and thus the benefits of a dynamic O–D is reduced. In the next simulation, we set the updating interval as 1 h. All the other settings are the same to the previous one. Figure 8(a) and (b) shows the comparisons of the simulated and observed traffic volumes at the five trailers with static and the dynamic O–D estimates. The slopes of the two scenarios are 1.0973 and 1.0928, respectively. Here, we also obtain better simulation results with the dynamic O–D method. But compared to the simulation with 10-min updating intervals, the results here are much worse, and the dynamic method is less effective at improving the simulation results for a 1-h interval. Table 4 shows the relative errors of traffic volumes at the five trailers before and after applying the dynamic estimation. We see with the dynamic method, the relative errors can be reduced by up to 13%. As expected, compared with the results for 10-min update interval, the benefits here are much smaller.
Modeling of transient conduction in building envelope assemblies: A review
Published in Science and Technology for the Built Environment, 2022
To utilize the CTS method, the building element’s total R-value or U-factor must be known, alongside a vector of CTS coefficients representing the thermal mass of the element. While the CTS of coefficients contains more variables than the thermal capacitance term of lumped capacitance method, this CTS vector can accurately simulate the effects of thermal mass compared to apparent thermal capacitance. This method also only requires a single computation of the CTS and can be utilized without the need for matrix inversion or iteration, unlike the finite element and finite difference methods. The one major downfall of the CTS method is the need for a vector of coefficients rather than a singular coefficient to represent thermal mass, similar to ISO 9869s dynamic method.
Seismic stability analysis of slope assuming log-spiral rupture surface using modified pseudo-dynamic method
Published in International Journal of Geotechnical Engineering, 2021
Let us consider a soil slope of height H, the failure surface of which is assumed to be log-spiral (QU in Figure 1). The slope is considered to be made up of ‘c–ϕ’ soil. It has been assumed that the occurrence of earthquake forces do not affect the basic soil parameters such as the cohesion of soil (c), internal friction angle of soil (ϕ) and the unit weight of the soil (γ). The present analysis is the evaluation of factor of safety of slope under the influence of weight of potential sliding mass and seismic inertia forces adopting modified pseudo-dynamic method based on visco-elastic behaviour of soil, which satisfies zero-stress boundary condition and considers soil amplification inherent to soil properties.