In this brief, a dynamic model of a mobile wheeled inverted pendulum (MWIP) system is improved considering friction forces, and a nonlinear disturbance observer (NDO)-based dynamic surface controller ...is investigated to control the MWIP system. Using a coordinate transformation, this non-Class-I type underactuated system is presented as a semistrict feedback form, which is convenient for dynamic surface controller design. A dynamic surface controller together with an NDO is designed to stabilize the underactuated plant. The proposed approach can compensate the external disturbances and the model uncertainties to improve the system performance significantly. The stability of the closed-loop MWIP system is proved by Lyapunov theorem. Experiment results are presented to illustrate the feasibility and efficiency of the proposed method.
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•The first construction of “Four in One” fingerprint system to evaluate Cistanche Herba quality.•The first comparison and analysis of two kinds of Cistanche Herba quality.•The first ...development and interpretation of 12 characteristic parameters of the DSC curve.•The first exploitation and establishment DSC quantum fingerprint of Cistanche Herba.•Assessing medicine and food homology quality with SQFM by integrating four technologies.
Cistanche Herba, known as “Desert Ginseng”, is widely sought after as a medicine and food homology. Owing to the one-sided quality control of several markers, a comprehensive “Four in One” fingerprint quality evaluation system based on HPLC, UV, FTIR and DSC was developed to ensure safety and improve quality. Except for HPLC quantitative analysis of echinacoside (1.41–60.23 mg/g) and acteoside (0.13–14.71 mg/g), UV and FTIR spectral analyses, 12 characteristic parameters of the DSC curve were first developed. Particularly, HPLC fingerprints with UV, FTIR and DSC quantum fingerprints established by merging point method were integrated to evaluate the sample quality with systematically quantified fingerprint method. 45 samples (Cistanche deserticola: 26 batches, Cistanche tubulosa: 19 batches) were evaluated separately to retain their fingerprint characteristics, whose significant inter batch differences and grade differentiation were manifested. This study can provide a comprehensive, strict and objective evaluation strategy for Cistanche Herba and even other samples.
•Bacuri fat is a natural source of palmitic acid, applicable in lipid nanoparticles.•Amazon oils present high MUFA/PUFA content and good oxidative stability.•Amazon fats could be good substitutes for ...hydrogenated oils.•Amazon fat/oil blends have interesting FA profiles and good nutritional indexes.•The designed blends broaden the range of applications of Amazonian fats and oils.
Considering their diversity, this work evaluated physical properties of Amazonian fats/oils (murumuru, tucuma kernel, bacuri, pracaxi, patawa, and Brazil nut). Solid fat content (SFC) curves and crystallization/melting profiles were determined. We also explored the possibilities of combining these lipids into blends to improve their nutritional and technological aspects. Patawa, pracaxi, and Brazil nut oils presented high levels of mono- and polyunsaturated fatty acids, displaying low atherogenicity and thrombogenicity indexes (0.10 and 0.18; 0.23 and 0.70; 0.20 and 0.42), respectively. The SFC curves showed that murumuru fat could be used as a cocoa butter replacer, whereas bacuri fat was found to be a promising alternative to hydrogenated oils in shortenings and spreads formulations. The blends expanded fats’ melting ranges and enriched their fatty acid compositions from a nutritional standpoint. This work shows that these fats, oils and their blends may be suitable for developing new products in the food industry.
This article proposes a non-smooth funnel control (NSFC) strategy based on the extended state observer (ESO) for motor-drive servo systems with unknown dynamics. These unknown dynamics, including the ...modeling error, the external disturbances, and the non-linear friction, are considered as a lumped disturbance. For estimating the unknown states and the lumped disturbance, a non-linear bandwidth extended state observer (NLB-ESO) is developed. The NLB designed using the Gaussian function and the position observation error can deal with the "peaking value problem" caused by the high observer gains. Furthermore, a funnel error surface is proposed based on the non-smooth error transformation (NSET) and incorporated into the dynamic surface control design procedure, where the NSFC can prescribe the position tracking error in a funnel region with small steady-state error and overshoot and short adjustment time. The non-smooth funnel error surface also avoids the singular problem in controller design by selecting the non-smooth parameter. Moreover, the stability of the closed-loop control system with the NLB-ESO is guaranteed by the Lyapunov theory. Comparative simulations and experiments show that the proposed NSFC can prescribe the tracking error in a funnel and ensure better tracking performance.
In this paper, a neuroadaptive fault-tolerant tracking control method is proposed for a class of time-delay pure-feedback systems in the presence of external disturbances and actuation faults. The ...proposed controller can achieve prescribed transient and steady-state performance, despite uncertain time delays and output constraints as well as actuation faults. By combining a tangent barrier Lyapunov-Krasovskii function with the dynamic surface control technique, the neural network unit in the developed control scheme is able to take its action from the very beginning and play its learning/approximating role safely during the entire system operational envelope, leading to enhanced control performance without the danger of violating compact set precondition. Furthermore, prescribed transient performance and output constraints are strictly ensured in the presence of nonaffine uncertainties, external disturbances, and undetectable actuation faults. The control strategy is also validated by numerical simulation.
Differential scanning calorimetry (DSC) has become a popular tool to investigate thermal transitions in food ingredients such as gelatin. Upon heating commercial gelatin samples beyond glass ...transition (
T
g
) and melting (
T
m
) temperatures, a relatively large endothermic transition (
T
i
) can be observed. We have observed that both the peak temperature and the enthalpy of the
T
i
transition are influenced by the integrity of the seal of the DSC pans used for the analysis. This study shows that escape of moisture from the DSC pan appears to be responsible for this effect. The effect of different types of DSC pans, as well as technique of sealing them on the
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i
transition were evaluated using DSC, SDT, and TG–MS.
•Homonuclear Ln(III) complexes.•Schiff base ligand.•The crystal field effect.•Photoluminescence studies.
New Schiff base complexes Ln(NO3)3H2L (where: Ln=Gd (1), Tb (2), Dy (3), Ho (4) and Er (5), ...H2L=N,N′-bis(5-bromo-3-methoxysalicylidene)propylene-1,3-diamine have been synthesized and characterized using elemental analysis, FTIR spectroscopy, thermogravimetric methods (TG–DSC), magnetic measurements, UV–Vis and luminescence studies. The compounds 1–5 follow the Curie–Weiss law all through the investigated temperature range 1.8–300K. The 1 shows behavior characteristic for the well-isolated mononuclear system whereas the magnetic properties of 2–5 are dominated by the crystal field effect on the Ln(III) site, masking the magnetic interaction between the paramagnetic centers. The Tb(III) complex 2 emits the characteristic metal centered luminescence.
•Bis(4-carboxyanilinium) sulphate (B4-CASO4) a new organo-sulphate adduct of 4-amino benzoic acid, was synthesized and it was found to crystallise in the monoclinic space group, P21/c, z = 4, with ...two 4-carboxyanilinium cations and a sulphate anion in an asymmetric unit.•Vibration band assignment of B4-CASO4 was carried out by comparing its spectrum with that of the partially deuterated B4-CASO4 and the reported assignment of the parent compounds 4-ABA and H2SO4.•The intermolecular interaction topology has been quantitatively analysed using the computational tool of energy framework analysis and very high values of interaction energies are found for the hydrogen bonded anion-cation pairs in the crystal structure of B4-CASO4.
Bis(4-carboxyanilinium) sulphate (B4-CASO4), a new organo-sulphate adduct of 4-amino benzoic acid, was synthesized and characterized by single-crystal X-ray diffraction, DSC and FTIR. B4-CASO4 crystallises in the monoclinic space group, P21/c, Z = 4, with two 4-CA cations and a sulphate anion in an asymmetric unit. These cations, 4-CA was found to exist as a cyclic acid dimer. In B4-CASO4 crystal the 4-CA cations and sulphate anions are connected through a three-dimensional network of strong charge-assisted N–H…O and C–OH…O hydrogen bonds. The infrared vibrational frequencies of B4-CASO4 were assigned and comparison of the spectral features of 4-ABA and B4-CASO4 suggest presence of a stronger NH…O and C–OH…O hydrogen bond interactions in B4-CASO4. Using the computational tool of energy framework analysis, the intermolecular interaction topology has been quantitatively analysed. A very high values of interaction energies are found for the hydrogen bonded anion-cation pairs in the crystal structure of B4-CASO4. The DSC, IR and computational results corroborate well with the structural data of B4-CASO4.
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The use of bovine LF as ingredient in infant formulas to mimic human milk composition is of great interest for the food industry; however, thermal treatments may induce denaturation of LF, reducing ...its nutritional benefits. In this study, the effect of four salts, authorized as additives for infant formulas (potassium phosphate (PP), sodium phosphate (SP), potassium citrate (PC) and sodium citrate (SC)), in the thermal stability of bovine LF, was studied. The concentration of soluble LF after applying different thermal treatments (90 °C, 2min and 120 °C, 30s) was determined by UPLC, while the structural changes induced by the additives were studied by ζ-potential, CD and DSC analyses. The results evidenced that LF undergoes thermal denaturation under the tested conditions. The addition of SP, PC and SC led to more negative surface charges and promoted a greater degree of unfolding. Contrarily, the LF-PP blend presented a slightly acidic pH and neutral charge and showed the same unfolding degree than LF alone. Interestingly, PP induced partial re-naturation upon cooling. In addition, the results show that PP and SC do not prevent the denaturation of LF, but they inhibit aggregation, keeping a relatively large proportion of soluble LF after the application of heating treatments.
•Heating temperature has a negative impact on the thermal denaturation of LF.•Na phosphate, K and Na citrate led to more negative charges and promoted unfolding.•K phosphate led to acidic pH and neutral charge and did not affect LF unfolding.•The presence of K phosphate induced partial re-naturation of LF upon cooling.•K phosphate and Na citrate do not prevent denaturation, but inhibit aggregation of LF.
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