Predictive temperature control design for reaction calorimeter based on mechanism parameter model.

Isothermal control is the most basic and crucial function in the principle of a reaction calorimeter system and affects the speed and validity of the calorimetric experiment. However, the complex and uncertain working conditions in different reaction processes pose a challenge to the adaptability of temperature control algorithms. Aiming at the problem, a heat transfer model of the system is first established for temperature control design. From the simulation results, a prediction model based on equivalent mechanism parameters is determined for the control. Then, an integrated model predictive control (MPC) strategy is presented. To reduce the influence on the temperature control caused by the mismatch of the prediction model, a set of online parameter identification and adjustment methods is proposed. Simulations of the MPC control were implemented to analyze the control's performance. Experiments were also carried out to verify the advantages of the proposed strategy over the proportional-integral-derivative algorithm and demonstrate the role and efficiency of online identification. This control strategy can be applied to other laboratory-scale instruments with tank reactors.

Vibrating capacitive electrostatic potential sensor based on a double cantilever tuning fork.

In this work, a vibrating capacitive sensor utilizing dual cantilever tuning fork resonance for electrostatic potential modulation was designed and fabricated. Initially, an electrostatic induction model was established, and the principle of non-contact electrostatic potential measurement was analyzed to identify the key factors influencing the sensor's performance. Subsequently, the vibration mode of the tuning fork was simulated to determine the mechanical dimensions of the tuning fork and the driving frequency of the piezoelectric crystal. Additionally, the concept of enhancing the uniformity of the electric field near the sensor by employing a shield plate was proposed. Simultaneously, the optimal mechanical parameters of the shielding plate were determined through multi-physical field simulation to improve the sensor's linearity. Finally, a compact calibration device was designed to measure the key performance parameters of the non-contact electrostatic potential sensor. The results demonstrate that the sensor has a measurement range of -10 to 10 kV, a measurement accuracy better than ±3%, and a linearity of 0.46%. This work offers an alternative solution for non-contact potential measurement.

Reaction Analysis and Process Optimization with Online Infrared Data Based on Kinetic Modeling and Partial Least Squares Quantitation.

In-situ Fourier transform infrared (FT-IR) spectroscopy has been recognized as an important technology for online monitoring of chemical reactions. However, analysis of the real-time IR data for identification and quantification of uncertain reactants or intermediates is often ambiguous and difficult. Here, we propose an analysis algorithm based on reaction kinetic modeling and the chemometric method of partial least squares (PLS) to comprehensively and quantitatively study reaction processes. Concentration profiles and apparent kinetic parameters can be simultaneously calculated from the spectral data, without the demand of complicated analysis on characteristic absorbance peaks or tedious sampling efforts for multivariate modeling. Paal-Knorr reactions and glyoxylic acid synthesis reactions were selected as typical reactions to validate the algorithm. A lack of fit of the Paal-Knorr reaction spectra was less than 2.5% at various conditions, and the absolute errors between the predicted values and HPLC measurement of glyoxylic acid synthesis were less than 6% during the reaction process. Moreover, the reaction kinetic models extracted from FT-IR data were used to simulate reaction processes and optimize the conditions in order to maximize product yields, which proved that this analysis method could be used for process optimization.

Mechanism and kinetic study of Paal-Knorr reaction based on in-situ MIR monitoring.

An in-depth understanding of reaction processes is beneficial to the development and quality control of chemical products. In this work, the mechanism and kinetics of the Paal-Knorr reaction for pyrrole derivatives are thoroughly studied using in-situ Fourier transform infrared (FTIR) spectroscopy. The hemiacetal amine intermediate, reactants, and products were identified and quantified by the treatment of real-time infrared spectra via chemometrics method and two-dimensional correlation spectroscopy (2DCOS) technique. Based on the IR quantitative models, influences of operating conditions on reaction processes were investigated, and the reaction kinetic model was built with kinetic parameters of two rate-limiting reaction steps calculated. This approach of analysis on the in-situ FTIR data demonstrated the ability to extract useful information on reaction components, especially the intermediate spectrum, from the confounding real-time IR data. The in-situ FTIR monitoring combined with the IR analysis methods is proved as a powerful tool for revealing the reaction mechanism and kinetics.

Correction of nonlinearities in series structure-based resistance thermometry readouts.

Series structure-based resistance thermometry readouts offer several advantages for multi-point temperature measurements. However, because of the diversity of nonlinear error sources and differences among channels in such readouts, existing nonlinear error correction methods are ineffective. In view of this situation, a nonlinear error correction method based on error source analysis is proposed. The proposed method first determines the impacts of error sources by analyzing the circuit architecture. The contributions of the common-mode rejection ratio and the mismatch between positive and opposite exciting currents are then eliminated using resistance bridge calibrators. Finally, the residuals are fitted to various polynomial functions. The results of experiments show that correction based on the proposed method results in a maximum nonlinear readout error of 1.87 × 10-5, compared with 4.01 × 10-5 using the classical method. Thus, the proposed method of nonlinear error correction is effective for series structure-based resistance thermometry readout.

[Case-control study on three spinal rotation manipulations for the treatment of lumbar disc herniation].

OBJECTIVE: To evaluate the efficacy and safety of three different spinal rotation manipulations for the treatment of lumbar disc herniation. METHODS: From September 2011 to April 2013,180 patients diagnosed as lumbar disc herniation were randomly divided into seat fixed rotation group (A), lateral position rotation group (B) and supine position rotation group (C) by using a digital table. Finally 10 patients were excluded and dropped, 170 patients were included in the study. There were 57 patients in group A, 57 patients in group B and 56 patients in group C. Baseline demographic characteristics of patients, clinical findings and indexes of health status had no statistically differences among three groups (P > 0.05). The manipulation was performed every other day, and the treatment duration for all patients was 3 weeks. Body pain (BP), Physical function (PF) in SF-36, Oswestry Disability Index (ODI) and adverse reactions were observed statistically 6 weeks, 3 months, 6 months, one year and two years after finishing treatment. RESULTS: BP, PF scores in 3 groups were significantly improved and ODI scores were significantly lower than those before treatment and the differences were statistically significant (P < 0.05); However, there was no significant difference among three groups in the BP, PF and ODI scores (P > 0.05). There were no obvious and serious adverse reactions among these groups. CONCLUSION: Based on the theory of dislocation of bone joints in TCM, three kinds of spinal rotation manipulations can be used safely for the treatment of lumbar disc herniation, and the efficacy was similar.

Effect of a Traditional Chinese Medicine combined therapy on adolescent idiopathic scoliosis: a randomized controlled trial.

OBJECTIVE: To evaluate the effectiveness of a combined Traditional Chinese Medicine (TCM) therapy versus conventional treatment on adolescent idiopathic scoliosis. METHODS: One hundred twenty outpatients with mild and moderate adolescent idiopathic scoliosis were randomly divided into a TCM group (TCMG) and a brace group (CG). TCMG patients underwent Daoyin, Tuina, and acupotomology therapies. CG patients were treated with a Milwaukee brace. Each patient's Cobb angle was measured after 12 and 24 months of treatment, and pulmonary function was determined after 12 months of treatment. Average electromyogram (AEMG) ratio of the surface electromyogram was measured after 6 and 12 months of treatment and followed-up after 18 and 24 months. RESULTS: The Cobb angle significantly decreased in both groups after 12 months of treatment compared with before treatment (P< 0.05). The percentages of original Cobb angle in TCMG and CG were 51.4% and 47.8% (P > 0.05) after 12 months and 62.5% and 34.7% (P < 0.05) after 24 months, respectively. Pulmonary function significantly improved after 12 months in TCMG (P < 0.05) but significantly decreased in CG (P < 0.05). The AEMG ratio was significantly lower (P < 0.01) and tended to remain at 1 after stopping treatment in TCMG, but increased in CG (P < 0.05). CONCLUSION: TCM combined therapy can prevent the progression of scoliosis. The AEMG ratio is a promising index that could replace radiography in the evaluation of treatment effect and progression in scoliosis.

[Application of surface electromyography in the treatment of adolescent idiopathic scoliosis with traditional spinal balanced therapy].

OBJECTIVE: To evaluate the values of surface electromyography (sEMG) in the treatment of adolescent idiophathic scoliosis (AIS) with non-surgical therapy. METHODS: From October 2011 to May 2012, the data of 33 patients with AIS underwent traditional spinal balanced therapy were analyzed. There were 14 males and 19 females with an average age of (15.40 +/- 3.01) years,ranging in Cobb angle from 13 degrees to 40 degrees, course of disease more than 3 months. X-rays showed 21 cases were type C and 9 cases were type S. Preoperative and postoperative 6 months, Cobb angle, the ratio of averaged electromyography paramete (AEMG), security of treatment were observed. RESULTS: Thirty cases (90.9%) accomplished the treatment and detection. No harmful effects to vital sign was found and no fracture, dislocation, apopsychia, infection of pin hole was found. There was positive correlation between the ratio of AEMG and Cobb angle (P = 0.003). The ratio of AEMG decreased after treatment,and indicated the improvement of myosthenic otherness. CONCLUSION: sEMG can be used as a objective examination in evaluating difference of muscle electricity activity on both concaved and convex sides for patients of AIS, so it is a qualified objective examination for effectiveness evaluation and assessment aggravation risk, and has great value in clinic.

[Randomized controlled trial on manipulation for the treatment of cervical vertigo of high flow velocity type].

OBJECTIVE: To explore the effects of manipulation and traction combined with Nimodipine on the blood flow velocity of vertebrobasilar artery (VBA) in cervical vertigo of high flow velocity,and to evaluate clinical therapeutic effects between two methods. METHODS: From March 2008 to Feburary 2009,70 patients who were diagnosed as high flow velocity of cervical vertigo were randomly divided into treatment group (35 cases) and control group (35 cases). Among 70 patients, 32 were male and 38 were female. The age ranged from 21 to 45 years with an average of 37.6 years. The disease course ranged from one day to two years with an average of 12.6 days. Patients of the treatment group were treated with manipulation for total three weeks, three times once week. The patients in the control group were treated with traction (weight ranged from 5 to 6 kg, 20 minutes each time, once every other day) and Nimodipine for total three weeks (three times each day, and with a dose of 40 mg each time). After three weeks, the changes of flow velacity of VBI and score before and after treatment were observed using transcranil Doppler (TCD) and Evaluation Scale for Cervical Vertigo. After six weeks, the therapeutic effects were assessed. RESULTS: The mean velocity in left vertebral artery (LVA), right vertebral artery (RVA) and basilar artery (BA) were obviously lower than those before treatment in two groups (P < 0.01). The LVA, RVA and BA of the treatment group was lower than those of control group after 3 weeks (P < 0.01). There was significant difference in vertigo score after treatment between the two groups. The improvement rate of double-sides sign in X-ray image and the therapeutic effects of treatment group was superior to that of control group (P < 0.01). CONCLUSION: The effect of manipulation on flow velocity of VBA is superior to that of traction combined with Nimodipine, and there are better therapeutic effects in treating cervical vertigo of high flow velocity in comparison with traction combined with Nimodipine. But there are more higher demands for manipulation's application.