arXiv subjects

David Munoz-Rodriguez

Publications and source records attributed to David Munoz-Rodriguez.

3 recordsLinked to original sources

arXiv2025

Thermochemical and elemental characterization of aromatic seed residues for solid biofuel applications in a circular economy context

This study investigates the energy valorization potential of 16 aromatic seed residues (ASW), a by-product generated after essential oil extraction from Mediterranean aromatic and medicinal plants. Driven by the increasing demand for natural bioactive ingredients and the expansion of aromatic crop production, large amounts of residual biomass remain underutilized. Their incorporation into thermochemical conversion routes aligns with circular economy strategies, offering opportunities for renewable energy generation, waste minimization, and the development of value-added bioenergy products. The objective of this work is to provide a comprehensive thermochemical, elemental, and structural assessment of ASW to determine their suitability for solid biofuel production (pellets, briquettes), pyrolysis for bio-oil generation, and biochar applications. The samples were analyzed under standardized ISO methodologies to ensure comparability and adherence to industrial fuel quality requirements.

physics.app-ph↗

arXiv2025

Innovation ARIMA models application to predict pressure variations in water supply networks with open-loop control. Case study in Noja (Cantabria, Spain)

Water utilities are increasingly concerned about losses, leaks, and illegal connections in their distribution networks. Pressure control is typically managed through pressure reducing valves with electrically controlled actuators based on predefined tables according to the pressure at the critical point control. This openloop control method lacks direct feedback between the PRV and CPC, making it challenging to distinguish whether pressure variations originate from normal head losses or abnormal network conditions. Unlike traditional applications of ARIMA focused on water demand forecasting, this study explores its novel use in pressure management within distribution networks, aiming to predict P3 pressure based on head losses across a defined hydraulic sector. To achieve this objective, a predictive model based on the Box-Jenkins methodology and its variations is implemented to analyse time series data. An action path is established to determine the optimal model ARIMA, ARMA, ARMAX, etc. which is subsequently validated using real operational data from Noja, a coastal town in northern Spain characterized by significant seasonal population fluctuations. By accurately forecasting CPC pressure, this system enhances the detection of anomalous patterns, enabling more efficient network pressure management. The study demonstrates the potential of advanced modelling techniques in optimizing water distribution networks, providing valuable insights to improve system efficiency, reliability, and sustainability in urban environments.

physics.app-ph↗

arXiv2025

Application of Time-Controlled Critical Point in Pressure Reducing Valves. A Case Study in North Spain

Potable water utilities are currently making great efforts to reduce leakage rates and assure long-term supply to the population due to the challenges of climate change, growing population and water shortage scenarios that have been on them over the last years. One of the most employed methods to reduce leakage includes the installation of pressurereducing valves along the water distribution network and the utilization of pressure management schemes. Pressure management includes different types of control models, which are applied according to the requirements of each site. The most advanced and sophisticated scheme is critical point control, which relies on a flow signal from a measuring device or online communication between the critical point and the valve. This paper proposes the utilization of a seasonal autoregressive integrated moving average, or the SARIMA model, to correlate pressure at the outlet of the valve and pressure on the critical point of the area supplied, aiming to set a fixed pressure in the critical point. The SARIMA model is developed according to historical data logged in the field and then validated. Later, the SARIMA model was tested on a real location in the village of Noja, Spain. The analysis of the field test results prove that the proposed model is feasible to be used since there is no significance difference between the target values set in the critical point and the real values measured in the field. The research proves that the SARIMA model can be used as an alternative for critical point control in water distribution networks when no flow signal is available or when communication between the critical point and the pressure reducing valve is not an option.

physics.app-ph↗