New approach for regulation of the internal recirculation flow rate by fuzzy logic in biological wastewater treatments.

The internal recirculation plays an important role on the different biological processes of wastewater treatment plants because it has a great influence on the concentration of pollutants, especially nutrients. Usually, the internal recirculation flow rate is kept fixed or manipulated by control techniques to maintain a fixed nitrate set-point in the last anoxic tank. This work proposes a new control strategy to manipulate the internal recirculation flow rate by applying a fuzzy controller. The proposed controller takes into account the effects of the internal recirculation flow rate on the inlet of the biological treatment and on the denitrification and nitrification processes with the aim of reducing violations of legally established limits of nitrogen and ammonia and also reducing operational costs. The proposed fuzzy controller is tested by simulation with the internationally known benchmark simulation model no. 2. The objective is to apply the proposed fuzzy controller in any control strategy, only replacing the manipulation of the internal recirculation flow rate, to improve the plant operation.Therefore, it has been implemented in five operation strategies from the literature, replacing their original internal recirculation flow rate control, and simulation results are compared with those of the original strategies. Results show improvements with the application of the proposed fuzzy controller of between 2.25 and 57.94% in reduction of total nitrogen limit violations, between 55.22 and 79.69% in reduction of ammonia limit violations and between 0.84 and 38.06% in cost reduction of pumping energy.

Fuzzy logic for plant-wide control of biological wastewater treatment process including greenhouse gas emissions.

The application of control strategies is increasingly used in wastewater treatment plants with the aim of improving effluent quality and reducing operating costs. Due to concerns about the progressive growth of greenhouse gas emissions (GHG), these are also currently being evaluated in wastewater treatment plants. The present article proposes a fuzzy controller for plant-wide control of the biological wastewater treatment process. Its design is based on 14 inputs and 6 outputs in order to reduce GHG emissions, nutrient concentration in the effluent and operational costs. The article explains and shows the effect of each one of the inputs and outputs of the fuzzy controller, as well as the relationship between them. Benchmark Simulation Model no 2 Gas is used for testing the proposed control strategy. The results of simulation results show that the fuzzy controller is able to reduce GHG emissions while improving, at the same time, the common criteria of effluent quality and operational costs.

Control strategies for nitrous oxide emissions reduction on wastewater treatment plants operation.

The present paper focused on reducing greenhouse gases emissions in wastewater treatment plants operation by application of suitable control strategies. Specifically, the objective is to reduce nitrous oxide emissions during the nitrification process. Incomplete nitrification in the aerobic tanks can lead to an accumulation of nitrite that triggers the nitrous oxide emissions. In order to avoid the peaks of nitrous oxide emissions, this paper proposes a cascade control configuration by manipulating the dissolved oxygen set-points in the aerobic tanks. This control strategy is combined with ammonia cascade control already applied in the literature. This is performed with the objective to take also into account effluent pollutants and operational costs. In addition, other greenhouse gases emissions sources are also evaluated. Results have been obtained by simulation, using a modified version of Benchmark Simulation Model no. 2, which takes into account greenhouse gases emissions. This is called Benchmark Simulation Model no. 2 Gas. The results show that the proposed control strategies are able to reduce by 29.86% of nitrous oxide emissions compared to the default control strategy, while maintaining a satisfactory trade-off between water quality and costs.

Can local corticosteroid injection in the retrocalcaneal bursa lead to rupture of the Achilles tendon and the medial head of the gastrocnemius muscle?

PURPOSE: The purpose of the study is to explain the cause-effect relationship in three patients who reported combined ruptures of the Achilles tendon and the gastrosoleus complex 6 months after they had received corticosteroids injections for the management of retrocalcaneal bursitis. METHODS: Three cryopreserved cadavers (three men, three left legs) were examined to assess the anatomic connection between the retrocalcaneal bursa and the Achilles tendon (distal and anterior fibers). Blue triptan medium contrast was injected. RESULTS: An unexpected connection between the retrocalcaneal bursa and the anterior fibers of the Achilles tendon was found in all instances. CONCLUSIONS: Local corticosteroid injection of the retrocalcaneal bursa may help the symptoms of retrocalcanear bursitis, but pose a risk of Achilles tendon rupture. This risk-benefit has to be taken into account when corticosteroid injections are prescribed to professional and high-level athletes.

[Discriminatory validity and association of the mini-mental test (MMSE) and the memory alteration test (M@T) with a neuropsychological battery in patients with amnestic mild cognitive impairment and Alzheimer's disease]. / Validez discriminativa y asociación del test minimental (MMSE) y del test de alteración de memoria (T@M) con una batería neuropsicológica en pacientes con deterioro cognitivo leve amnésico y enfermedad de Alzheimer.

AIMS: To establish the discriminatory validity of the mini-mental test (MMSE) and the memory alteration test (M@T) for the diagnosis of amnestic mild cognitive impairment (aMCI) and probable Alzheimer's disease (AD), and also to study the association between the results obtained in screening tests, a neuropsychological battery and a functional questionnaire in healthy persons and in patients with aMCI and AD. SUBJECTS AND METHODS: We evaluated 27 normal controls, 27 patients with aMCI and 35 patients with AD using the MMSE and a memory screening test, the M@T, a neuropsychological battery and a questionnaire on functional activities of daily living. Pearson correlation coefficients were used to evaluate the relations between the scores on the M@T and the MMSE and the neuropsychological tests. The area below the curve, the sensitivity and the specificity were calculated for the screening tests. RESULTS: In patients with aMCI, the scores on the M@T and the MMSE were strongly associated with the performance in the episodic memory tests in frontal tests and with the scores on the functional questionnaire, but not with tests that evaluated praxias and perceptive functions. In patients with AD, the scores on the M@T and the MMSE were associated with results in semantic memory, language, executive functions and praxias, but not with perceptive tests and functional questionnaires. CONCLUSIONS: In patients with aMCI and AD, the association between MMSE and M@T only correlate with some cognitive functions, without there being any association with other cognitive functions. Therefore, screening tests cannot be used as the only instrument for evaluating the cognitive status in patients with suspected dementia.

Central aponeurosis tears of the rectus femoris: practical sonographic prognosis.

OBJECTIVE: This study is a statistical analysis to establish whether a correlation exists between the level and degree of rectus femoris (RF) central tendon injury and the amount of time that an athlete is unable to participate subsequently, referred to as "sports participation absence" (SPA). DESIGN: Causal-comparative study. PATIENTS: 35 players from two high-level Spanish soccer teams with an injury to the central tendon of the RF based on clinical and ultrasound criteria. MAIN OUTCOME MEASURE: Ultrasound examination was performed with an 8-2 MHz linear multifrequency transducer. All studies included both longitudinal and transverse RF sections. RESULTS: At the proximal level the SPA time is 45.1 days when the injury length is 4.0 cm. This value increases by 5.3 days with each 1 cm increase in the length of injury. In the case of distal level injury, SPA time is 32.9 days when the injury length is 3.9 cm. This value increases by 3.4 days with each 1 cm increase. In the total representative sample, SPA time when the injury length is 4.2 cm corresponds to 39.1 days. This value increases by 4.2 days per length unit. CONCLUSIONS: RF central tendon injury at the proximal level is associated with a greater SPA time than at the distal level. Patients with a grade II injury have an SPA time longer than those with a grade I injury whether the injury is located proximal or distal.