Thermophilic and mesophilic temperature phase anaerobic codigestion (TPAcD) compared with single-stage co-digestion of sewage sludge and sugar beet pulp lixiviation

The performance of temperature phase anaerobic co-digestion (TPAcD) for sewage sludge and sugar beet pulp lixiviation (using the process of exchanging the digesting substrate between spatially separated thermophilic and mesophilic digesters) was tested and compared to both single-stage mesophilic and thermophilic anaerobic co-digestion. Two Hydraulic Retention Times (HRT) were studied in the thermophilic stage of anaerobic digestion in two temperature phases, maintaining the optimum time of the mesophilic stage at 10 days, obtained as such in single-stage anaerobic co-digestion. In this way, we obtained the advantages of both temperature regimes. Volatile solids removal efficiency from the TPAcD system depended on the sludge exchange rate, but fell within the 72.6e64.6% range. This was higher than the value of 46.8% obtained with single-stage thermophilic digestion and that of 40.5% obtained with mesophilic digestion. The specific methane yield was 424e468 ml CH4 per gram of volatile solids removed, similar to that of single-stage mesophilic anaerobic digestion. The increase in microbial activity inside the reactor was directly proportional to the organic loading rate (OLR) (or inversely proportional to the HRT) and inversely proportional to the size of the microbial population in single-stage anaerobic co-digestion systems

Robust high-accuracy high-speed continuous-time CMOS current comparator

The authors present a CMOS current comparator which employs nonlinear negative feedback to obtain high-accuracy (down to 1.5pA) and high-speed for low input currents (8ns at 50nA). The new structure features a speed improvement of more than two orders of magnitude for a 1 nA input current, when compared to the fastest reported to date

A mismatch-insensitive high-accuracy high-speed continuous-time current comparator in low voltage CMOS

This paper presents a CMOS current comparator which employs nonlinear feedback to obtain high-accuracy (down to 1.5 pA) and high-speed for low input currents (8 ns@50 nA). This structure is much faster for low currents (below 10 /spl mu/A) than other previous nonlinear feedback comparators. Particularly, when compared to the fastest current comparator reported up to now, the new one operates at more that 100 times faster for a 1 nA current, with smaller area occupation and similar power consumption. In addition, the new comparator is virtually insensitive to mismatch and capable of operating with supply voltages as low as 1 V

Gestión administrativa de los servicios públicos en la Municipalidad Distrital de Comas, 2019

La presente investigación titulada “Gestión administrativa de los servicios públicos en la municipalidad distrital de comas, 2019.” tuvo como objetivo general analizar cómo es la gestión administrativa del distrito de comas, 2019. Como parte del análisis de los datos en el desarrollo de la presente investigación, se siguió el procedimiento de categorización, cuyo paradigma de la investigación fue interpretativo, enfoque cualitativo, diseño fenomenológico, donde el escenario de estudio fue la Municipalidad de Comas, 2019. En el procedimiento de recolección de datos se utilizaron como técnicas a la entrevista y análisis normas y fuentes documentales, cuyos instrumentos fueron la guía de preguntas de entrevista y fichas de análisis. En el análisis de los datos se emplearon métodos descriptivos, analíticos, y método inductivo. Se concluye que la gestión administrativa de los servicios públicos del distrito, avanza a paso lento y deficiente ya que no cubre la demanda de los usuarios, puesto que no cuenta con suficiente personal profesional capacitado ni con presupuesto adecuado para prestar servicio al vecino Comeño

Mind the gap of leadership : the gender mentoring program of the Building Engineering School

In order to enhance women's leadership, a Gender Mentoring Program (GMP) was implemented at the Escuela Técnica Superior de Edificación (ETSEM) from the Technical University of Madrid (UPM), during the academic year 2014-2015. This paper evaluates the GMP experience highlighting the advantages and barriers found during its implementation and giving remedial actions for the following years. The analysis carried out was mainly performed using the questionnaires answered in the sessions and the satisfaction surveys completed by all participants regarding different aspects of the GMP. Results show a high dropout rate as only 50% of the mentees completed the GMP and attended to all the sessions. 100% of them considered that the support given by the mentors was the most valued item of the Program. Moreover, 36% of mentees were very satisfied with the knowledge and the leadership experience gained, and 41% would recommend participating in the GMP. In general, the overall assessment of the Mentoring is very positive since 100% of respondents rated it above 4 (out of 5). Finally, giving ECTS credits to the mentees and reducing the duration of the program ? finishing all the training sessions in September and therefore avoiding the exams period in December?, are some of the remedial actions planned to be implemented next course in order to keep up students? participation and decrease their dropout rate

A SIMULINK Block Set for the High-Level Simulation of Multistandard Radio Receivers

This paper describes a SIMULINK block set for the behavioral simulation of RF receivers. Building blocks are modeled including their main circuit-level non idealities. These models are incorporated into the SIMULINK environment making an extensive use of C-coded S-functions and reducing the number of library block elements. This approach reduces the simulation time while keeping high accuracy, what makes the proposed toolbox very appropriate to be combined with an optimizer for the automated high-level synthesis of radio receivers. As a case study, a direct-conversion receiver intended for 4G telecom systems is modeled and simulated using the proposed toolbox.This work has been supported by the Spanish Ministry of Science and Education (with support from the European Regional Development Fund) under contract TEC2004-01752/MIC.Peer reviewe

A novel low-voltage reconfigurable ΣΔ modulator for 4G wireless receivers

Trabajo presentado al 23rd DCIS celebrado en Grenoble (Francia) del 12 al 14 de noviembre de 2008.This paper presents a new adaptable cascade ΣΔ modulator architecture for low-voltage multi-standard applications. It uses two reconfiguration strategies: a programmable global resonation and a variable loop-filter order. These techniques are properly combined in a novel topology that allows to increase the effective resolution in a given bandwidth, whereas keeping relaxed output swing requirements and high robustness to mismatch and to non-linearities of the amplifiers. Time-domain simulations including the main circuit-level non-idealities are shown to demonstrate the benefits of the presented modulator when it is configured to cope with the requirements of GSM, UMTS, WLAN and Wi-Max.This work has been supported by the Spanish Ministry of Science and Education (with support from the European Regional Development Fund) under contract TEC2007-67247-C02-01/MIC and the Andalusian (Regional) Ministry of Innovation, Science and Enterprise under contract TIC-2532.Peer Reviewe

A novel low-voltage reconfigurable ΣΔ modulator for 4G wireless receivers

This paper presents a new adaptable cascade ΣΔ modulator architecture fo r low-voltage multi-stan- dard applications. It uses two reconfiguration strategies: a programmable global resonation and a variable loop-filter order. These techniques are properly com- bined in a novel topology that allows to increase the effec- tive resolution in a given bandwidth, whereas keeping relaxed output swing requirements and high robustness to mismatch and to non-linearities of the amplifiers. Time-domain simulations incl uding the main circuit-level non-idealities are shown to demonstrate the benefits of the presented modulator when it is configured to cope with the requirements of GSM, UMTS, WLAN and Wi-Max.España, Ministerio de Educación y Ciencia TEC2007-67247-C02-01/MICEspaña, Ministerio de Innovación, Ciencia y Empresa, Junta de Andalucía TIC-253

CMOS SPADs selection, modeling and characterization towards image sensors implementation

The selection, modeling and characterization of Single Photon Avalanche Diodes (SPADs) are presented. Working with the standard 180nm UMC CMOS process, different SPAD structures are proposed in combination with several quenching circuits in order to compare their relative performances. Various configurations for the active region and the prevention of the premature edge breakdown are tested, looking for a miniaturization of the devices to implement image sensor arrays without loses in their performance

Characterization-Based Modeling of Retriggering and Afterpulsing for Passively Quenched CMOS SPADs

The current trend in the design of systems based on CMOS SPADs is to adopt smaller technological nodes, allowing the co-integration of additional electronics for the implementation of complex digital systems on chip. Due to their simplicity, a way to reduce the area occupied by the integrated electronics is the use of passive quenching circuits (PQCs) instead of active (AQCs) or mixed (MQCs) ones. However, the recharge phase in PQCs is slower, so the device can be retriggered before this phase ends. This paper studies the phenomena of afterpulsing and retriggering, depending on the characteristics of the SPADs and the working conditions. In order to do that, a test chip containing SPADs of different size has been characterized in several operating environments. A mathematical model has been proposed for fitting afterpulsing phenomenon. It is shown that retriggering can be also described in terms of this model, suggesting that it is linked to carriers trapped in the shallow levels of the semiconductor and that should be taken into account when considering the total amount of afterpulsing events.Junta de Andalucía TIC 233