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The discrete-time fault-tolerant control method for permanent magnet synchronous motors (PMSMs) is investigated for the first time in this paper based on adaptive fuzzy theory, where the designed controllers consider faults containing both loss of effectiveness and bias. Firstly, with the help of Euler method, the discrete-time model of PMSMs is obtained. Secondly, adaptive fuzzy theory is used to realize fault-tolerant control of PMSMs. Next, dynamic surface control is used to resolve the problems of “explosion of complexity” and noncausal in discrete-time systems caused by backstepping. It is proved that the proposed method can guarantee all signals and states in the closed-loop system are semi-global uniform ultimate bounded when the faults occur and the position tracking error can converge to a small neighborhood of the origin. Finally, simulation results show that the proposed control method has strong fault-tolerant performance and robustness.

In the pharmaceutical industry, processing granular materials is inevitable when manufacturing solid dosage forms, such as tablets, capsules, dry powder inhalants, vascular stent, or injectable solid compositions. As pharmaceutical industries make products that necessitate a significant (albeit controllable) risk to human health, a systematic, proactive, scientific, and risk-based approach has been adopted by health authorities (e.g., Food and Drug Administrative) for drug safety: Quality-by-Design (QbD). The QbD-based pharmaceutical development emphasizes the mechanistic understanding of input material properties and process dynamics to recognize how the formulation and process factors affect the final product. Once we have comprehensive material and process understanding, the manufacturing process is stable and predictable, the performance and safety of the final product can be predicted and ensured, the entire drug product development can run faster with less waste and cost. In the last decade, the pharmaceutical industries have grasped a world-wide transformation to continuous manufacturing technologies due to its capability of fast development, enhanced risk management, and improved quality control. The deep understanding of material behavior and process dynamics on the continuous manufacturing platform will be one of the primary focuses for the entire pharmaceutical industry in the next decades. By considering all of the above regulatory requirements and state-of-the-art pharmaceutical techniques, this dissertation is constructed toward unraveling the possible correlation between material properties, process parameters, and product performance, based on continuous manufacturing platform for solid dosage development. In each chapter, attempts have been made to investigate a) how the certain properties of an input material impact its process behavior and performance of output material or final product, b) how the certain process parameters alter process dynamics which further impact the performance of output material or final product, and c) how to design formulation and production methodology to enhance drug productivity or therapeutic performance. Four specific investigations are implemented: (1) The effect of twin-screw feeders on material properties is investigated to understand whether the post-feeder powder has the same properties as the pre-feeder one. The flowing behavior of fourteen pharmaceutical powders is characterized before and after feeder. it has been found that powder may behave more cohesively after passing through a twin-screw feeder due to electrostatic charge acquisition. Such behavior can only be discerned by performing the appropriate characterization method, which can be correlated with the tendency of powder electrostatic charging and its particle size, (2) API agglomeration behavior during the continuous process is investigated. A novel method for quantifying material agglomeration tendency is developed based on image analysis. It enables us to assess the risk of non-uniform products caused by ingredient agglomeration. In this work, it has been found that the powder is densified in the twin-screw feeder and then introduced as lumps to the downstream process, which generates difficulty for uniform mixing. Twenty-two pharmaceutical powders are examined and the capability is developed to assess ingredient agglomeration risk based on proper raw material characterization.(3) The existence of API agglomerates reduces content uniformity of the final product. we also explore how to design blending processes to diminish or even eliminate API agglomerates, which are generated due to feeder passage. A case study is performed in a continuous powder blending system, which consists of two feeders, a conical mill, and a tubular blender. Multiple blending protocols are implemented, involving different impeller rotational speed of blender, multiple levels of powder holdup in blender, with/without using the conical mill at multiple impeller speeds and screen size. It has been found that the API agglomerates can be significantly reduced when powder passes through an extensive number of blades (NOB) in a blender, or a conical mill is assembled(4) Improving the dissolution of poorly soluble drug products is a key challenge in drug product development. In this dissertation, a novel approach is invented to enhance the dissolution of poorly soluble drugs by applying the concept of the surface coating. A simple process, twin-screw extrusion at low process temperature, is performed that enables the melt-coating of API particles with a small amount of surfactant. Four case studies are conducted to evidence the practicality of the melt-coating methodology, in which the combinations of three BCS class II drugs and three surfactants are examined. Remarkably, the results support that the melt-coating technique significantly improves the dissolution of poorly soluble drugs.

Tablets is the most convenient way to take medication and 70% of the total medicines are dispensed in the form of tablets. The effectiveness of such dosage form depends on how the drug dissolves in the fluids of the gastrointestinal tract. The dissolution of tablets is dominated by two factors mainly: Wettability of the blends and disintegration of the tablets. The objective of this study consists of: A) Studying the wettability of pharmaceutical blends by droplet penetration method. B) Understanding of the Swelling of pharmaceutical tablets in contact with water. In droplet penetration section, blends of 90% Lactose, 9% APAP, 1% MgSt with varying shear level (0Rev, 160Rev, 640Rev and 1280Rev) were prepared as porous material. To characterize wettability of blends, the penetration profile of both water and silicone oil, which is the volume of droplet versus time, was plotted. The water penetration process consists of three phase: bouncing phase, waiting phase and penetrating phase. By reviewing the penetration model developed by Denesuk, a new method for dynamic contact angle calculation was developed. The results reveal that the wettability of blends decreases as the increasing of shear level. In tablets swelling section, formulations with varying percentage of Avicel and Lactose (80% Avicel-10% Lactose, 45% Avicel-45% Lactose and 10% Avicel-80% Lactose) were used to make tablets with different compaction force ranging from 4KN to 24KN. A experiment was designed to measure the swelling of tablets and mass of water uptake meantime. Both the swelling profile and the water uptake profile of tablets present two behaviors: linear and non-linear, which reveal two possible liquid uptake mechanisms: capillary penetration and particle swelling. Swelling rate and water uptake rate of tablets can be calculated from the swelling profile and water uptake profile. Both of them are non-monotonic with compaction and formulation.

China's atmospheric environment is seriously polluted in resent years. People's physical and mental health is strongly influenced by environmental pollution which can be represented as smog. In order to solve such a problem caused by long-term excessive emissions, source-directed measures should be taken. As a big coal consumer, power system's air pollution emission is large. “Reducing green house gas emission and saving energy” becomes the main challenge of power system's development. Power system environmental optimal dispatch containing air quality forecast is researched, neural network algorithm is used to predict urban air pollutant concentration and the concentration is transformed into atmospheric environment capacity by numerical method in this paper. The simulation results indicate that economic cost and environmental cost are fully considered and the total pollutant emissions significantly decrease.

Nanocrystalline MgAl 2 O 4 with average crystal sizes of about 100 nm were prepared by citrate sol–gel process at lower temperatures. The presence of small amounts of MgAl 2 O 4 as crystal seed could obviously accelerate the crystallization of MgAl 2 O 4 . The effects of the amount and the size of crystal seeds on the formation of MgAl 2 O 4 were investigated. The inceptive formation temperature of the MgAl 2 O 4 not containing any crystal seeds was 600 °C, while the specimen containing 1 wt.% MgAl 2 O 4 used as a crystal seed was 550 °C. The decrease in the inceptive formation temperature was due to MgAl 2 O 4 serving as a substrate for heterogeneous nucleation which accelerated nucleation. The amount and the size of crystal seeds showed little influence on the formation of MgAl 2 O 4 spinel. The prepared ultrafine MgAl 2 O 4 spinel were characterized by X-ray diffraction (XRD), differential thermal analysis and thermogravimetric (TG–DTA) and scanning electron microscopy (SEM).

Ultrafine MgAl{sub 2}O{sub 4} was synthesized by citrate sol-gel process. A model was presented to evaluate the concentration of species in a citric solution for preparing MgAl{sub 2}O{sub 4} ultrafine powder. The evaluated concentration of species can provide valuable information and help in selecting the optimal condition for preparation of MgAl{sub 2}O{sub 4} powder by citrate sol-gel process. The influence of molar ratio of cations, citric acid and pH on the formation of MgAl{sub 2}O{sub 4} was studied. The spinel precursor gel and the ultrafine MgAl{sub 2}O{sub 4} spinel were characterized by X-ray diffraction (XRD), differential thermal analysis, thermogravimetric (TG-DTA) and scanning electron microscope (SEM). The results show that the MgAl{sub 2}O{sub 4} spinel phase begins to form at 600 deg. C, and most of MgAl{sub 2}O{sub 4} crystals are spherical with a crystal size about 30-50 nm.