Energy and Exergy Analyses of Rice Drying in a Novel Electric Stationary Bed Grain-Drying System with Internal Circulation of the Drying Medium

In our study, we developed a system to reduce both energy consumption and pollutant discharge during the drying process. We present a new technology, a stationary bed grain-drying test device based on the internal circulation of the drying medium (ICODM). A rice-drying experiment was carried out inside of it, and the influences of air temperature (AT) and air velocity (AV) on the energy and exergy efficiencies (EEE) as well as the improvement potential rate (IPR) and the sustainability index (SI) of the rice-drying process were studied. The following conclusions were obtained: when the rice was dried at a temperature of below 55 °C and an AV across the grain layer of 0.5 m/s, the average EEE during the drying process was 48.27–72.17% and 40.27–71.07%, respectively, demonstrating an increasing trend as the drying medium temperature increased. When the rice was dried using an AV across the grain layer in the range of 0.33–0.5 m/s and a temperature of 40 °C, the two values were 39.79–73.9% and 49.66–71.04%, respectively, demonstrating a decreasing trend as the drying medium flow velocity increased. IPR and SI were 4.1–8.5 J/s and 1.9–2.7, respectively, at a drying temperature of 30–55 °C and an AV of 0.33–0.5 m/s. These conclusions can provide helpful guidance for the optimization and control of the rice-drying process in terms of saving energy.

Runoff optimization and control for basin water allocation

The water distribution plan for the three major irrigation districts (Changma, Shuangta, and Huahai) in the Shule River Basin in the planned year was analyzed in this study in an effort to resolve the insufficient natural endowment of water resources and contradiction between supply and demand throughout the basin. Based on this plan, and under the condition of satisfying the scheduling constraints of cascade reservoirs, the minimum total water supply shortage in the watershed was taken as the main goal coupled with the cascade reservoir runoff optimization control coefficient. An optimized dispatch model of the reservoir group was established accordingly. The large system coordination decomposition algorithm was called to solve the model and obtain the water scheduling scheme of each reservoir. After the optimal regulation of runoff, the water demand of the three major irrigation areas of Changma, Shuangta, and Huahai in the planned year is greater than the available water resources of the Shule River and the Petroleum River. The total surface runoff water shortage is 66.01 million m3, which cannot be satisfied. Among the reservoirs, Shuangta has the highest water shortage quota of 43.503 million m3, followed by Chijinxia with a water deficit quota of 22.18 million m3, and finally by Changma with a minimum water shortage quota of 0.3277 million m3. The results of this work may provide technical support for water resource allocation and regulations, as well as for the efficient usage of the Shule River Basin.

Uncertainty Quantification for Additive Manufacturing Process Improvement: Recent Advances

This paper reviews the state of the art in applying uncertainty quantification (UQ) methods to additive manufacturing (AM). Physics-based as well as data-driven models are increasingly being developed and refined in order to support process optimization and control objectives in AM, in particular to maximize the quality and minimize the variability of the AM product. However, before using these models for decision-making, a fundamental question that needs to be answered is to what degree the models can be trusted, and consider the various uncertainty sources that affect their prediction. Uncertainty quantification (UQ) in AM is not trivial because of the complex multi-physics, multi-scale phenomena in the AM process. This article reviews the literature on UQ methodologies focusing on model uncertainty, discusses the corresponding activities of calibration, verification and validation, and examines their applications reported in the AM literature. The extension of current UQ methodologies to additive manufacturing needs to address multi-physics, multi-scale interactions, increasing presence of data-driven models, high cost of manufacturing, and complexity of measurements. The activities that need to be undertaken in order to implement verification, calibration, and validation for AM are discussed. Literature on using the results of UQ activities towards AM process optimization and control (thus supporting maximization of quality and minimization of variability) is also reviewed. Future research needs both in terms of UQ and decision-making in AM are outlined.

Optimization and Control of a Planar Three Degrees of Freedom Manipulator with Cable Actuation

The paper analyzes a planar three degrees of freedom manipulator with cable actuation. Such a system can be understood as a special type of hybrid parallel kinematic mechanism composed of the rigid serial chain and the additional auxiliary cable system. The advantage of the auxiliary cable mechanism is the ability to reconfigure the whole system. The fulfillment of sufficient prestressing is the constraint of the optimization process. Computed Torque Control with a cable force distribution algorithm is implemented. The control algorithm performance is examined on different trajectories, including non-smooth motion requests, and its robustness is tested by randomly generated errors of the model parameters in regulators. The results demonstrate that the optimized structure is capable of controlling the manipulator motion and keeping the cable prestressing within the given limits.

Investigating the dynamic characteristics of the hydrostatic bearing spindle system with active piezoelectric restrictors

Studies show that active control technology can improve system performance and meet the increasing industrial demand in diverse applications. In the present study, the dynamic characteristics of the bearing-spindle system based on active piezoelectric (PZT) restrictors, including the amplitude-frequency and phase-frequency characteristics are analyzed theoretically and experimentally. In the analysis, the influence of the pipeline model on the system characteristics is studied. Then the feasibility and effectiveness of the active control method are verified through experiments. It is demonstrated that the theoretical and experimental results are consistent. The present study is expected to provide a guideline for further investigations on the structural optimization and control law design for active hydrostatic oil-film bearing spindle systems.

Advancements in Optimization and Control Techniques for Intensifying Processes

Process Intensification (PI) is a vast and growing area in Chemical Engineering, which deals with the enhancement of current technology to enable improved efficiency; energy, cost, and environmental impact reduction; small size; and better integration with the other equipment. Since process intensification results in novel, but complex, systems, it is necessary to rely on optimization and control techniques that can cope with such new processes. Therefore, this review presents some advancements in the field of process intensification that are worthy of exploring in detail in the coming years. At the end, several important open questions that can be taken into consideration in the coming years are listed.