Method development and validation for analysis of microencapsulated cyanidin-3-O-rutinoside in dairy samples containing juçara palm fruit by high-performance liquid chromatography

Euterpe edulis is a plant native of Brazil and popularly known as juçara. The aim of this study was to develop and validate an analytical method using high-performance liquid chromatography (HPLC) of juçara crude extracts (JCEs) and to evaluate dairy products containing free and microencapsulated extracts. The validated analytical method for JCE was performed using cyanidin-3-O-rutinoside (C3R – isolated and identified as major component from JCE) as a reference: linearity was obtained using ten concentrations between 25 and 250 μg mL⁻¹ (R² = 0.994); limits of detection and quantification were 19.04 μg mL⁻¹ and 57.7 μg mL⁻¹ respectively; accuracy (relative standard deviation) was <5%; recovery was 104.85 μg mL⁻¹; and the method is robust. Physicochemical analyses of the dairy products were evaluated using colour, pH, and concentration of anthocyanins using HPLC calculated as C3R over 21 days of storage. The pH remained stable until the end of the test. The colour and the concentration of anthocyanins remained stable for 9 days. C3R was isolated, the HPLC method was developed and validated, and the colour stability was not altered until 9 days. © 2023 Society of Chemical Industry.     

A Note on the GLA’s Choice of the Current Loser from the Perspective of Factorizability

Boersma’s (1997, 1998) Gradual Learning Algorithm (GLA) performs a sequence of slight re-rankings of the constraint set triggered by mistakes on the incoming stream of data. Data consist of underlying forms paired with the corresponding winner forms. At each iteration, the algorithm needs to complete the current data pair with a corresponding loser form. Tesar and Smolensky (Linguist Inq 29:229–268, 1998) suggest that this current loser should be set equal to the winner predicted by the current ranking. This paper develops a new argument for Tesar and Smolensky’s proposal, based on the GLA’s factorizability. The underlying typology often encodes non-interacting phonological processes, so that it factorizes into smaller typologies that encode a single process each. The GLA should be able to take advantage of this factorizability, in the sense that a run of the algorithm on the original typology should factorize into independent runs on the factor typologies. Factorizability of the GLA is guaranteed provided the current loser is set equal to the current prediction, providing new support for Tesar and Smolensky’s proposal.     

Sensorless adaptive output feedback control of wind energy systems with PMS generators

This paper addresses the problem of controlling wind energy conversion (WEC) systems involving permanent magnet synchronous generator (PMSG) fed by IGBT-based buck-to-buck rectifier–inverter. The prime control objective is to maximize wind energy extraction which cannot be achieved without letting the wind turbine rotor operate in variable-speed mode. Interestingly, the present study features the achievement of the above energetic goal without resorting to sensors of wind velocity, PMSG speed and load torque. To this end, an adaptive output-feedback control strategy devoid of any mechanical sensor is developed (called sensorless), based on the nonlinear model of the whole controlled system and only using electrical variables measurements. This control strategy involves: (i) a sensorless online reference-speed optimizer designed using the turbine power characteristic to meet the maximum power point tracking (MPPT) requirement; (ii) a nonlinear speed regulator designed by using the backstepping technique; (iii) a sensorless interconnected adaptive state observer providing online estimates of the rotor position as well as speed and load/turbine torque. The proposed output-feedback control strategy is backed by a formal analysis showing that all control objectives are actually achieved. Several simulations show that the control strategy enjoys additional robustness properties.     

Output feedback control of wind energy conversion system involving a doubly fed induction generator

This paper deals with the problem of controlling a wind energy conversion system (WECS) based on the doubly fed induction generator (DFIG), by IGBT‐based back‐to‐back rectifier‐inverter. The goal of control is to maximize wind energy extraction letting the wind turbine rotor operate in a variable‐speed mode. Interestingly, the present study features the achievement of the above energetic goal without resorting to sensors for wind velocity. The control strategy involves: (i) an output feedback non‐linear regulator designed by the backstepping technique and based on the use of a high gain observer; (ii) a sensorless online reference‐speed optimizer designed using the turbine power characteristic to achieve the maximum power point tracking (MPPT) requirement. It is formally shown that the proposed controller actually meets its control objectives. This theoretical result is confirmed by several simulations.     

A New Approach to the SCI Journal Citation Reports,a System for Evaluating Scientific Journals

The Science Citation Index, Journal Citation Reports (JCR), published by the Institute for Scientific Information (ISI) and designed to rank, evaluate, categorize and compare journals, is used in a wide scientific context as a tool for evaluating researchers and research work, through the use of just one of its indicators, the impact factor. With the aim of obtaining an overall and synthetic perspective of impact factor values, we studied the frequency distributions of this indicator using the box-plot method. Using this method we divided the journals listed in the JCR into five groups (low, lower central, upper central, high and extreme). These groups position the journal in relation to its competitors. Thus, the group designated as extreme contains the journals with high impact factors which are deemed to be prestigious by the scientific community. We used the JCR data from 1996 to determine these groups, firstly for all subject categories combined (all 4779 journals) and then for each of the 183 ISI subject categories. We then substituted the indicator value for each journal by the name of the group in which it was classified. The journal group may differ from one subject category to another. In this article, we present a guide for evaluating journals constructed as described above. It provides a comprehensive and synthetic view of two of the most used sections of the JCR. It makes it possible to make more accurate and complete judgements on and through the journals, and avoids an oversimplified view of the complex reality of the world of journals. It immediately reveals the scientific subject category where the journal is best positioned. Also, whereas it used to be difficult to make intra- and interdisciplinary comparisons, this is now possible without having to consult the different sections of the JCR. We construct this guide each year using indicators published in the JCR by the ISI.     

Influence of surface topography on the wear of hot forging dies

Forging processes are widely employed in the manufacture of consumer goods. The forging dies have machined cavities which usually are produced by high speed milling (HSM) with ball nose tools and, consequently, their final surfaces have a characteristic topography generated by the cutting conditions. The purpose of this study was to gain a better understanding of the correlation between the surface topography of a milled die and its wear during the hot forging process. To this end, dies were produced by milling process with four different types of topography, using distinct cutting conditions, and were tested by forging typical workpieces. The best tribological performance was achieved with the topography composed of micro cavities generated by high values of feed per tooth (f _z) and radial depth of cut (a _e) in the milling process, because it enabled the retention of a larger amount of lubricant, thus minimizing the adhesion of workpiece material on the die. Moreover, the use of high values of f _z and a _e reduced the production time of a die. Low values of f _z and a _e produced the opposite results, i.e., the worst tribological performance and the longest production time, indicating that their use should be avoided.     

The potential for self-sanitisation of faecal sludge by intrinsic ammonia

Faecal sludge has the potential to be used as a sustainable fertiliser in agriculture, but the sludge must be sanitised due to its content of pathogenic microorganisms. The intrinsic ammonia from the urine may be sufficient for sanitisation of the sludge if it is not too diluted by flush water or lost by ventilation. To evaluate the potential for this sanitisation method, inactivation of Enterococcus faecalis, Salmonella typhimurium and Ascaris suum eggs during treatment were assessed. The inactivation was studied at different storage temperatures (10–28 °C) and in several sludge mixes with different contents of urine, faeces and flush water, and with ammonia concentrations from 40 to 400 mM. All pathogens were inactivated by the ammonia, and ascaris eggs were the most persistent. Lower flush water volume and higher urine content favoured inactivation, mainly due to increased uncharged ammonia (NH₃) concentration. The lag phase in ascaris inactivation was shortened by increasing temperature and NH₃ concentration, while post-lag phase inactivation was not influenced by NH₃ concentration. Faecal sludge can be sanitised by airtight storage without the use of additives when flush water volumes are sufficiently low. For temperatures of 23–28 °C, a 3 log reduction of ascaris egg viability can be achieved within 1–6 months depending on ammonia concentration and temperature.     

An adaptive control strategy for wound rotor synchronous machines

This paper addresses the problem of controlling wound rotor synchronous motors in association with their power conversion components, i.e. AC/DC rectifiers and DC/AC inverters. Considering the whole association, ‘converter‐motor’ makes it possible to account, in addition to motor speed regulation, four other important control objectives such as power factor correction with respect to the supply net and DC link voltage regulation. To achieve these objectives, an adaptive control strategy is developed, based on a nonlinear model of the whole ‘converter‐motor’ association. Adaptation is motivated by the uncertain nature of some motor characteristics, especially the mechanical parameters. The closed‐loop system stability and performances are formally described using averaging theory. Copyright © 2012 John Wiley & Sons, Ltd.