Calibration of pipeline ADC with pruned Volterra kernels

A Volterra model is used to calibrate a pipeline ADC simulated in Cadence Virtuoso using the STMicroelectronics CMOS 45 nm process. The ADC was designed to work at 50 MSps, but it is simulated at up to 125 MSps, proving that calibration using a Volterra model can significantly increase sampling frequency. Equivalent number of bits (ENOB) improves by 1-2.5 bits (6-15 dB) with 37101 model parameters. The complexity of the calibration algorithm is reduced using different lengths for each Volterra kernels and performing iterative pruning. System identification is performed by least squares techniques with a set of sinusoids at different frequencies spanning the whole Nyquist band. A comparison with simplified Volterra models proposed in the literature shows better performance for the pruned Volterra model with comparable complexity, improving linearity by as much as 1.5 bits more than the other techniques

A standardized comparison of peri-operative complications after minimally invasive esophagectomy: Ivor Lewis versus McKeown.

BACKGROUND: While our institutional approach to esophageal resection for cancer has traditionally favored a minimally invasive (MI) 3-hole, McKeown esophagectomy (MIE 3-hole) during the last five years several factors has determined a shift in our practice with an increasing number of minimally invasive Ivor Lewis (MIE IL) resections being performed. We compared peri-operative outcomes of the two procedures, hypothesizing that MIE IL would be less morbid in the peri-operative setting compared to MIE 3-hole. METHODS: Our institution\u27s IRB-approved esophageal database was queried to identify all patients who underwent totally MI esophagectomy (MIE IL vs. MIE 3-hole) from June 2011 to May 2016. Patient demographics, preoperative and peri-operative data, as well as post-operative complications were compared between the two groups. Post-operative complications were analyzed using the Clavien-Dindo classification system. RESULTS: There were 110 patients who underwent totally MI esophagectomy (MIE IL n = 49 [45%], MIE 3-hole n = 61 [55%]). The majority of patients were men (n = 91, 83%) with a median age of 62.5 (range 31-83). Preoperative risk stratifiers such as ECOG score, ASA, and Charlson Comorbidity Index were not significantly different between groups. Anastomotic leak rate was 2.0% in the MIE IL group compared to 6.6% in the MIE 3-hole group (p = 0.379). The rate of serious (Clavien-Dindo 3, 4, or 5) post-operative complications was significantly less in the MIE IL group (34.7 vs. 59.0%, p = 0.013). Serious pulmonary complications were not significantly different (16.3 vs. 26.2%, p = 0.251) between the two groups. CONCLUSIONS: In this cohort, totally MIE IL showed significantly less severe peri-operative morbidity than MIE 3-hole, but similar rates of serious pulmonary complications and anastomotic leaks. These findings confirm the safety of minimally invasive Ivor Lewis esophagectomies for esophageal cancer when oncologically and clinically appropriate. Minimally invasive McKeown esophagectomy remains a satisfactory and appropriate option when clinically indicated

Experimental calibration and validation of a simulation model for fault detection of HVAC systems and application to a case study

Automated fault detection and diagnostics (FDD) could provide a cornerstone for predictive maintenance of heating, ventilation and air-conditioning (HVAC) systems based on the development of simulation models able to accurately compare the faulty operation with respect to nominal conditions. In this paper, several experiments have been carried out for assessing the performance of the HVAC unit (nominal cooling/heating capacity of 5.0/5.0 kW) controlling the thermo-hygrometric comfort inside a 4.0 × 4.0 × 3.6 m test room at the Department of Architecture and Industrial Design of the University of Campania Luigi Vanvitelli (Italy); then, a detailed dynamic simulation model has been developed and validated by contrasting the predictions with the measured data. The model has also been used to analyze the dynamic variations of key parameters associated to faulty operation in comparison to normal performance, in order to identify simplified rules for detection of any non-optimal states of HVAC devices. Finally, the simulated performance of the HVAC unit has also been investigated while serving a typical Italian building office with and without the occurrence of typical faults with the main aim of assessing the impact of the faults on thermo-hygrometric comfort conditions as well as electric energy consumption

Preliminary symptoms assessment of typical faults related to the fans and humidifiers of HVAC systems based on experimental data collected during Italian summer and winter

The symptoms associated to the occurrence of typical faults in a heating, ventilation and air-conditioning (HVAC) system, including a single duct dual fan constant air volume air-handling unit, have been experimentally characterized. The operation of the HVAC unit with 3 artificially forced faults ((1) reduced velocity of the supply air fan, (2) reduced velocity of the return air fan, (3) the valve supplying the humidifier kept always closed) has been analysed and compared with that of healthy operation of the same plant under very similar boundary conditions (outside air temperature and initial indoor air temperature) during Italian summer and winter in order to preliminarily assess (i) the effects on the main operating parameters, and (ii) generate preliminary operation data to assist further research in fault detection and diagnosis of HVAC systems

Healthy and Faulty Experimental Performance of a Typical HVAC System under Italian Climatic Conditions: Artificial Neural Network-Based Model and Fault Impact Assessment

The heating, ventilation, and air conditioning (HVAC) system serving the test room of the SENS i-Lab of the Department of Architecture and Industrial Design of the University of Campania Luigi Vanvitelli (Aversa, south of Italy) has been experimentally investigated through a series of tests performed during both summer and winter under both normal and faulty scenarios. In particular, five distinct typical faults have been artificially implemented in the HVAC system and analyzed during transient and steady-state operation. An optimal artificial neural network-based system model has been created in the MATLAB platform and verified by contrasting the experimental data with the predictions of twenty-two different neural network architectures. The selected artificial neural network architecture has been coupled with a dynamic simulation model developed by using the TRaNsient SYStems (TRNSYS) software platform with the main aims of (i) making available an experimental dataset characterized by labeled normal and faulty data covering a wide range of operating and climatic conditions; (ii) providing an accurate simulation tool able to generate operation data for assisting further research in fault detection and diagnosis of HVAC units; and (iii) evaluating the impact of selected faults on occupant indoor thermo-hygrometric comfort, temporal trends of key operating system parameters, and electric energy consumptions

Preliminary Study to Develop an Alternative Method for the Non-targeted Determination of Xenobiotics in Food by Means of Ultra High Performance Liquid Chromatography Coupled to High Resolution and Accuracy Mass Spectrometry

This preliminary study describes the use of high resolution and accuracy mass spectrometry techniques combined with new generation chemical software products for detecting and identifying contaminants in food commodities. As a first step, the extracts of routine target analysis samples (obtained in our official laboratory responsible for food residues control) were acquired and processed with this method in order to search unknown and non-targeted contaminants in food. In order to verify the feasibility of the presented method, the research has been firstly addressed to untargeted pesticides and their metabolites in stone fruits commodities and tomatoes. The differential analysis carried with Compound Discoverer 2.0 between the investigated unknown sample and the blank matrix sample allowed to remove all the matrix molecular components; Aggregated Computational Toxicology Resource (ACToR) helped to understand and predict chemical interpretation of substances. The acquisition in FullScan-AIF and FullScanddMS2 allowed the clear detection and identification of isobaric compounds such as quinalphos and phoxim. In order to verify that the proposed method is suitable to the scope of application, the main points of SANTE/11813/2017 Document have been followed. The results demonstrate that no false positives and no false negatives have been detected from the analysis of samples spiked with pesticides at 0.010 and 0.10 mg kg−1. This preliminary study has been also tested with a Proficiency Test (EUPT-FV-SM08) and, according to EUPT-FV-SM08 Final Report, our laboratory has been included in the 67% (56) that clearly detected over 70% pesticides. Finally, this method has been extended to other matrices and contaminants

DYNAMIC SIMULATION OF A SOLAR HEATING AND COOLING SYSTEM INCLUDING A SEASONAL STORAGE SERVING A SMALL ITALIAN RESIDENTIAL DISTRICT

A centralized solar hybrid heating and cooling system satisfying the thermal, cooling and sanitary water demands of a typical Italian small district composed of six residential buildings situated in Naples (southern Italy) is modelled, simulated and analysed through the software TRNSYS over a period of 5 years. The plant is based on the operation of solar thermal collectors coupled with seasonal borehole storage; the solar field is also composed of photovoltaic solar panels connected with electric energy storage. An adsorption chiller powered by solar energy is adopted for cooling purposes, while a condensing boiler is used as an auxiliary unit. The performance of the proposed system has been assessed from energy, environmental and economic points of view and contrasted with the operation of a typical Italian heating and cooling plant, highlighting the following main results: saving of primary energy consumption up to 40.2%; (decrease of equivalent CO2 emissions up to 38.4%; reduction of operating costs up to 40.1%; and simple pay-back period of about 20 years

Molecular-dynamics calculations of thermodynamic properties of metastable alloys

In order to improve our current understanding of the microscopic structure of metastable alloys of immiscible elements such as Ag-Cu and Co-Cu, the Helmholtz free energy of several microstructures based on an fcc unit cell has been calculated and compared with that of a reference state. The microstructures considered for the free energy calculations at fixed volume are (1) a structure formed by alternating layers of fixed thickness of metal 1 and metal 2 separated by coherent interfaces; (2) an atomically disordered solid solution; (3) a structure comprising a random distribution of elemental cubic grains separated by coherent interfaces. Numerical results show that the Helmholtz free energy of structure (3) decreases with increasing grain size and that its value calculated for a sufficiently large grain size approaches the free energy of structure (1). Further molecular-dynamics simulations for the Ag-Cu system have allowed the calculation of the enthalpy at the equilibrium volume of several microstructures including some of those listed above. A comparison of the calculated values of the enthalpy with the heat release observed experimentally allows the advancement of an hypothesis concerning the reaction path and the structure of the equiatomic Ag-Cu alloy obtained by ball milling

Faulty Operation of Coils’ and Humidifier Valves in a Typical Air-Handling Unit: Experimental Impact Assessment of Indoor Comfort and Patterns of Operating Parameters under Mediterranean Climatic Conditions

Data-driven Automated Fault Detection and Diagnosis (AFDD) are recognized as one of the most promising options to improve the efficiency of Air-Handling Units (AHUs). In this study, the field operation of a typical single-duct dual-fan constant air volume AHU is investigated through a series of experiments carried out under Mediterranean (southern Italy) climatic conditions considering both fault-free and faulty scenarios. The AHU performances are analyzed while artificially introducing the following five different typical faults: (1) post-heating coil valve stuck at 100% (always open); (2) post-heating coil valve stuck at 0% (always closed); (3) cooling coil valve stuck at 100% (always open); (4) cooling coil valve stuck at 0% (always closed); (5) humidifier valve stuck at 0% (always closed). The measured faulty data are compared against the corresponding fault-free performance measured under the same boundary conditions with the aim of assessing the faults’ impact on both thermal/hygrometric indoor conditions, as well as patterns of 16 different key operating parameters. The results of this study can help building operators and facility engineers in identifying faults’ symptoms in typical AHUs and facilitate the related development of new AFDD tools