David Rodríguez Salgado

A Quantitative Analysis of Cold Water for Human Consumption in Hospitals in Spain

An estimation of the water used for human consumption in hospitals is essential to determine possible savings and to fix criteria to improve the design of new water consumption models. The present work reports on cold water for human consumption (CWHC) in hospitals in Spain and determines the possible savings. In the period of 2005–2012, 80 Eco-Management and Audit Schemes (EMAS) from 20 hospitals were analysed. The results conclude that the average annual consumption of CWHC is 1.59 m3/m2 (with a standard deviation of 0.48 m3/m2), 195.85 m3/bed (standard deviation 70.07 m3/bed), or 53.69 m3/worker (standard deviation 16.64 m3/worker). The results demonstrate the possibility of saving 5,600,000 m3 of water per year. Assuming the cost of water as approximately 1.22 €/m3, annual savings are estimated as 6,832,000 €. Furthermore, 2,912 MWh of energy could be saved, and the emission of 22,400 annual tonnes of CO2 into the atmosphere could be avoided.

Contribution of Surface Finish Monitoring Signals in CNC Taper Turning

On-line monitoring systems eliminate the need for post-process evaluation, reduce production time and costs, and enhance automation of the process. The cutting forces, mechanical vibration and acoustic emission signals obtained using dynamometer, accelerometer, and acoustic emission sensors respectively have been extensively used to monitor several aspects of the cutting processes in automated machining operations. Notwithstanding, determining the optimum selection of on-line signals is crucial to enhancing system optimization requiring a low computational load yet effective prediction of cutting process parameters. This study assess the contribution of three types of signals for the on-line monitoring and diagnosis of the surface finish (Ra) in automated taper turning operations. Systems design were based on predictive models obtained from regression analysis and artificial neural networks, involving numerical parameters that characterize cutting force signals (Fx, Fy, Fz), mechanical vibration (ax, ay, az), and acoustic emission (EARMS).

Assessment of Energy Consumption in Spanish Hospitals

In this chapter, assessment of energy consumption in Spanish hospitals is analysed. The quantification of energy consumption in hospitals is essential to save energy and establish design criteria. Average energy consumption in hospitals in Spain adds up to about 20% of the total energy consumed in the service sector. The aim of this paper is to analyse and quantify the final average energy consumption in hospitals in Spain according to appropriate parameters, including built surface area, number of bed and number of employees. The results show that the average annual energy consumption in normal operation conditions in the hospitals under study can serve as a starting point for the development of indicators in order to quantify the exact consumption of energy. They can also help to set optimal hospital infrastructure through healthcare engineering.

Design of semi-rigid wearable devices based on skin strain analysis

Nowadays, both usability and comfort play a key role in the development of medical and wearable products. When designing any device that is in contact with the human body, the mechanical behaviour of the embraced soft tissue must be known. The unavoidable displacement of the soft tissue during motion may lead to discomfort adn, thus, the withdrawal of the wearable product. This work presents a new methodology to design and test a wearable device based on the measurement of the dynamic skin strain field. Furthermore, from this field, the anatomical lines with minimum strain (Lines of non extension, LoNEs) are calculated to design the structural parts of the wearable device. Whith this new criteria, the resulting product is not only optimized to reduce the friction in skin-device interface, but fully personalized to the patients morphology and motion. The methodology is applied to the design of an ankle-foot wearable orthosis for subjects with ankle dorsiflexors muscles weakness due to nervous system disorders. The results confirm that the use of LoNEs may benefit the design of products with a high interaction with the skin.

Reverse Engineering Applied to the Teaching of Computer Aided Manufacturing

One of the main shortcomings of individualized training in the use of computer aided design (CAD), and computer aided manufacturing (CAM) tools is that students lack a sound and broad understanding of the type of tools, and their specific and integrated applications in industrial manufacturing. This study aimed to design an integrated curricular training programme in computer aided tools for the design and manufacture of mechanical components based on reverse engineering techniques. By using real products that students can see and touch, a scanned copy is obtained for subsequent reconstruction into a virtual three-dimensional model using the software for optimizing the point cloud, meshing, and creating both the surface and solid. Once the virtual three-dimensional model has been obtained, it is exported to a solid modelling CAD (3D-CAD) software for modification according to the geometrical requirements. The next step is for students to manufacture a component using rapid prototyping techniques, which allow them to visualize, analyse, and inspect a component to optimize its design. The use of computer aided manufacturing software enables students to design and plan machining operations virtually to obtain a computer numeric control (CNC) program for the manufacture of a component with a CNC machine tool. Finally, students perform a quality control of the component by employing a range of measurement techniques. This training program is integrated into the subjects of the mechanical engineering degree, where students can work with these tools in line with an intergraded curriculum.

APLICACIÓN DE TECNOLOGÍAS DE PROTOTIPADO RÁPIDO EN LA FABRICACIÓN DE DISPOSITIVOS ORTOPROTÉSICOS

En este trabajo se presenta una revision de los diferentes metodos de prototipado rapido aplicados a la industria ortoprotesica. En concreto se analizan los procesos de fabricacion de ayudas ortotoprotesicas, dispositivos destinados bien a corregir una determinada patologia (ortesis) o bien a sustituir la funcionalidad de un segmento corporal perdido (protesis). Los metodos tradicionales de fabricacion de estos dispositivos se basan en la fabricacion artesanal, en la que las medidas se adquieren mediante moldes de escayola y la construccion se realiza de manera individual, ajustando sobre el cuerpo del cliente. Aunque esta industria ha incorporado herramientas de Diseno y Fabricacion Asistida por Ordenador (CAD-CAM), la verdadera revolucion viene de la mano de las tecnologias de prototipado rapido. Tecnicas como el Modelado por Deposicion de Fundido (FDM), Sinterizado Selectivo por Laser (SLS), Fabricacion de Objetos Laminados (FOL) e impresion 3D por inyeccion de polimero son algunas de las metodologias existentes en la industria de la fabricacion, que poco a poco se van incorporando al mercado de la Ingenieria de Rehabilitacion, especialidad en auge y con grandes expectativas de crecimiento. En este trabajo se analizan las diferentes metodologias existentes para la fabricacion aditiva de dispositivos funcionales destinados a la rehabilitacion (ayudas ortoprotesicas). Ademas se senala la importancia de incluir estas tecnicas de fabricacion en la industria de rehabilitacion.

A Tool Wear Monitoring System for Steel and Aluminium Alloys Based on the same Sensor Signals and Decision Strategy

This paper presents a tool wear monitoring system that uses the same signals and prediction strategy for monitoring the machining process of different materials, i.e., a steel and an aluminium alloy. It is an important requirement for a monitoring system to be applied in real applications. Experiments have been performed on a lathe over a range of different cutting conditions, and TiN coated tools were used. The monitoring signals used are the AC feed drive motor current and the cutting vibrations. The geometry tool parameters used as inputs are the tool angle and the radius. The performance of the proposed system was validated against different experiments. In particular, different tests were performed using different numbers of experiments obtaining a rmse for tool wear estimation of 17.63 μm and 13.45 μm for steel and aluminium alloys respectively.

Surface Roughness Obtained With And Without The Use Of A Mechanical Spindle Speeder In Milling: A Comparative Study

In this paper a comparative study between the surface roughness obtained in a milling process and in the same process using a mechanical spindle speeder with aluminum workpieces is presented. Mechanical spindle speeders are one of the cheapest solutions to upgrade a conventional machine tool to high‐speed machining. The two machining processes were made under the same cutting conditions, covering a wide range of the cutting conditions with all the experiments. The surface roughness (Ra) is the value measured to obtain the comparative between the two machining operations. It must be noted that when the cutting speed is low (less than 6000 rpm), independently of the feed rate, the surface roughness obtained with the spindle speeder is higher. Nevertheless, the surface roughness is less at higher values of the tool cutting speed when the spindle speeder is used for machining. As result, the optimal cutting conditions for the use of mechanical spindle speeders are determined.

A Time‐Domain Modal Parameter Identification for CNC Machine Tools Using Singular Spectrum Analysis (SSA)

Modal parameter identification of machine tool axis drives is conventionally achieved by first obtaining frequency response curves from experimental data and then implementing a curve fitting procedure. The principal shortcomings of this procedure are the inherent limitations of the Fourier Transform method, used in obtaining the frequency responses, especially when non‐stationary signals appear. As an alternative to the conventional method, a new time‐domain modal parameter identification technique based in Singular Spectrum Analysis (SSA) is proposed and applied to CNC machine tool axis drive using output‐data only.