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  • Open access
  • 54 Reads
Indoor Household Air Quality Assessment: The case of the use of low cost sensor

According to World Health Organisation (WHO) over 4 million people die world-wide in 2012. This was due to one of the indoor contributors - particulate matter (PM) of a diameter 2.5. The use of low-cost PM measurements is assisting individuals to take actions by providing personalized information on indoor concentrations in real time. The low-cost sensor – SentinAir used in this study was designed and developed by group of researchers from ENEA-Italian National Agency for New Technologies, Energy and Environment. Sustainable Development Department, Research Center of Brindisi, Italy. It measures PM (1, 2.5, 10), NO2, SO2, CO2, O3, temperature, and relative humidity. The aim of this study was to deploy the sensor into the indoor (kitchen) of a household with the view of assessing all the parameters over a period of thirty (30) days as a preliminary investigation measurement. The protocol of the sensor was strictly followed. The results (mean) depicted: PM 1 (17.80 µg/m3), PM 2.5 (25.21 µg/m3), PM 10 (27.61 µg/m3), CO2 (435.3 ppm), O3 (24.75 ppb), NO2 (66.52 ppb), SO2 (48.04 ppb), temperature (34.1 oC), and humidity (64 %). When these results were compared with the WHO and National Environmental Standards and Regulations Enforcement Agency (NESREA) it was observed that the PM2.5 and 10 were within the 24 h guideline values of 25 and 50 µg/m3 respectively. Although that of PM 2.5 may be a risk. There were significant influences of temperature and humidity on the pollutants. Food frying and baking generated the largest increase in PM, in the kitchen activity. Because the data is reproducible, it is recommended that this low-cost PM sensor be integrated into an indoor air-quality measurement network to assist individuals in managing their personal exposure.

  • Open access
  • 40 Reads
Optical Investigation of PVA/ PbTiO3 Composite for UV Protective Approaches Applications.
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A new-fangled polymer of poly(vinyl alcohol) (PVA) doped with various concentrations of lead(II) Titanate (PbTiO3, PT) is prepared using the casting technique method. The prepared samples are identified by Attenuated Total Reflection- Fourier Transform Infrared (ATR-FTIR). The peaks characterized to PVA at 3280, 2917, 1690, 1425, 1324, 1081, 839 cm-1 appeared, also the peak characterized to the presence of PbTiO3 appeared at 713 cm-1. The interaction between PVA and PbTiO3 was confirmed by observing the change in IR absorption intensity. Optical properties were determined by Urbach theory and direct transition theory. The absorption edge values and the band tail energies decrease with increasing PbTiO3. The values of direct and indirect band gaps decrease with increasing PbTiO3 contents, indicating a variance in internal states by increasing PbTiO3. Composite with 10 wt.% PbTiO3 is promising for UV protective applications.

  • Open access
  • 36 Reads
The 3D-Printed Low-Cost Delta Robot Oscar: Technology Overview and Benchmarking

Robotics is undoubtedly one of the most influential fields of modern technology in changing the very nature of our society. Parallel Delta-robots have for a long time been mainly focused on a niche market but compared to serial anthropomorphic robots they present several simplicity and improved dynamics features. Additive manufacturing and 3D-printing technologies have enabled rapid changes in robotic engineering as we classically know it, allowing for greater creativity and freedom in machine design innovation and maintenance. The effective benefits of far-reaching design freedom in terms of geometry, materials and manufacturing accessibility, are now starting to become apparent, answering many complex technical questions and scientific uncertainties that go beyond basic design and functional knowledge and that require engineering skills and scientific analysis. The Delta robot, as one of the most important industrialized parallel robots because of its simplicity, is considered in this work, covering an overview of multidisciplinary aspects of Delta robots, mechatronics design, interface software and virtualization technologies, and the benchmarking of the new 3D-printed and low-cost SMILE.TECH’s Delta robot Oscar.

  • Open access
  • 74 Reads
Manufacturing and Testing of 3D-Printed Polymer Isogrid Lattice Cylindrical Shell Structures

Additive manufacturing (AM) and 3D printing technologies are rapidly transforming structural and machine design engineering as we classically know it, enabling increased creativity and design freedom. Freely available and widely disseminated computer-aided design and manufacturing software, allied with the easily accessible and affordable commercial 3D printers and materials available these days, have fostered a boom in the number of users and potential applications for these technologies. This article will focus on the use of Fused Deposition Modeling technology (FDM) to manufacture by 3D printing polymer isogrid lattice cylindrical shell structures with equilateral triangular unit-cells. The 3D model of these structures is created parametrically and automatically in SolidWorks using VBA programming language. Several configurations of the lattice cylindrical shell are modeled, manufactured and tested, with the purpose of assessing compressive structural strength, stiffness and to investigate local buckling instability.

  • Open access
  • 63 Reads
Intelligent Networked Vehicle CAN Bus Network Real-time monitoring and active defense system

With the maturity of automotive intelligent network technology, the number of ECUs loaded on vehicles by different car manufacturers is increasing year by year. Anyone can access the inside of CAN bus through OBD-II, Bluetooth and other vehicle peripheral devices and cloud network to get ECU data or even forged data. The current attack detection and defense technology is mainly established in the offline intrusion detection method and post-event defense system, which is difficult to meet the real-time and security of the car driving.

For the real-time detection and defense mechanism of CAN bus, we propose a data-based anomaly detection algorithm to identify anomalous information and attack types. A real-time intrusion detection model is established according to different attack types to propose suitable encryption and authentication methods for CAN bus to achieve the purpose of active defense. The network environment of real vehicle CAN bus is simulated in CANoe software. It is able to detect the intrusion of five different attack types such as Replay and Flood. According to the attack model, the data anomalies are found in real time to eliminate unnecessary hidden dangers and meet the requirements of real-time defense in the vehicle driving.The joint experimental results of the CANoe software and the STM32F407 show that the type of attack can be effectively detected and a 99.8% defense rate is achieved out of 10,000 messages tested. The time required to perform one detection and defense is 2.25ms, which is much smaller than the time required to send and receive messages on the CAN bus (10ms). Therefore, it meets the requirements of CAN bus for real time, etc.

  • Open access
  • 79 Reads
A Real-Time Snore Detector Using Neural Networks and Selected Sound Features

Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS) is a chronic condition held responsible for a number of well-documented effects on patients’ health. It is linked to increased cardiovascular morbidity and mortality, including sudden heart death [1], while an estimated 4% and 2% of the male and female population respectively suffer from OSAHS. Interestingly enough, an estimated 85% of patients remain undiagnosed [2]. This underestimation poses an increased risk for individuals and society as a whole and is mainly due to polysomnography being the only method for OSAHS diagnosis currently trusted by doctors. Polysomnography is a time and resource-consuming procedure that monitors sleep with a multitude of specialized sensors and equipment and is performed in dedicated sleep laboratories or hospital care clinics. As such, most of the suffering population remains unscreened and, hence, undiagnosed.

Screening the disease’s symptoms at home could be used as an alternative approach in order to alert individuals that potentially suffer from OSAHS without compromising their everyday routine. Since snoring is usually linked to OSAHS, developing a snore detector is appealing as an enabling technology for screening OSAHS at home using ubiquitous equipment like commodity microphones (included in, e.g., smartphones). Within the context of the APNEA research project [3], we developed a snore detection tool and herein present our approach and selection of specific sound features that discriminate snoring vs. environmental sounds, as well as the performance of the proposed tool. Furthermore, a Real-Time Snore Detector (RTSD) is built upon the snore detection tool and employed in whole-night sleep sound recordings resulting to a large dataset of snoring sound excerpts that are made freely available to the public. The RTSD may be used either as a stand-alone tool that offers insight to an individual’s sleep quality or as an independent component of OSAHS screening applications in future developments.

[1] Qaseem, A., et al., “Management of obstructive sleep apnea in adults: a clinical practice guideline from the American College of Physicians”, Annals of Internal Medicine, October 2013, DOI: 10.7326/0003-4819-159-7-201310010-00704.

[2] Pack, A. I., “Advances in sleep-disordered breathing”, American Journal of Respiratory and Critical Care Medicine, January 2006, DOI: 10.1164/rccm.200509-1478OE.

[3] APNEA Project: “Automatic pre-hospital and in-home screening of sleep apnea”, Operational Programme “Competitiveness, Entrepreneurship and Innovation”, website: (accessed on April, 01, 2021).

  • Open access
  • 101 Reads
Quality Analysis of a Demonstration 3D-Printed Tool Steel Part

3D-printed metal parts manufactured by laser powder bed fusion method are considered in this article. Uncertainties regarding the homogeneity of powder raw material properties and the obtained mechanical properties of the 3D printed parts using a tool steel are investigated. A demonstration tool steel part is characterized in terms of geometry and shape limitations, chemical composition, microstructure, roughness and hardness, with the purpose of assessing the material homogeneity, the effect of heat treatments and the mechanical performance of 3D printed parts that can be used for the production and replacement of critical mechanical components using conventional manufacturing processes.

  • Open access
  • 51 Reads
Preliminary Design and Validation of a 3D-Printed Continuously Variable Transmission for an Electric Vehicle Prototype

This paper aims to present the developments on the design of a new 3D-printed continuously variable transmission (CVT) developed for an electric vehicle prototype competing in Shell Eco-marathon electric battery category, a world-wide energy efficiency competition sponsored by Shell. The proposed system is composed of a polymeric conic pulley assembled in the motor axle and directly coupled to the rear tire of the vehicle. The conical shape allows to implement a continuous variation of the pulley diameter in contact with the tire. The motor with the pulley was mounted over a board with linear bearings, allowing the speed ratio to change by moving the board laterally. In the manufacturing process, additive manufacturing tools such as 3D printing by fused deposition modeling were used to simplify the manufacturing process reducing costs and time. A computational simulation model of the vehicle prototype with the CVT was also created in Matlab/Simulink environment and the simulated results were compared to experimental data acquired with the manufactured variable transmission. The designed powertrain allows mass reduction, better vehicle performance and increased speed range output using a simple and easily manufactured 3D-printed solution.

  • Open access
  • 66 Reads
Concise Review of Acoustic Guitar Modeling Technologies

Numerical modeling and simulation of multiphysics coupled systems is still a potentially fruitful field of research, even when it comes to intrinsically linear or linearized formulations. This is usually the case with computational models of vibroacoustics coupled systems, where it is not uncommon that the combined effect of many localized geometrical missmodeling with significant uncertainty in mechanical characterization of some materials - typical for organic fibers, for instance - propagates to large discrepancies in the natural frequencies and mode shapes obtained from ordinary finite element analysis. The main goal of this work is to compare two basic approaches for the modeling of stringed musical instruments in the frequency domain: finite element modal analysis and simplified lumped-parameters analytic modeling considering only the most influencing degrees-of-freedom (accordingly yielding the first few resonances). Thus, the focus here is to review some important references in this topic, including previous work from the authors which is expected to bring useful alternative ways of addressing some specific problems. Albeit restricted to the slowly varying structural behavior, simplified analytic models proved well capable of closely representing the dynamics of the lower frequency range, while still amenable to the identification of its parameters through simple routines relying on experimental data. On the other hand, properly updated finite element models allowed long-sought connections between physically relevant values and crucial subjective quality descriptors - essential pieces of musicians' and luthier's vocabulary - to be eventually found.

  • Open access
  • 75 Reads
Optical Chemosensors to measure specific markers in transformers insulating oil exploiting Molecularly Imprinted Polymers and Plasmonic Optical Fibers

2-FAL (2-furaldehyde) and 5HMF (5-(hydroxymethyl-furfural) are two main by-products of the thermal degradation of cellulose paper insulation of power transformers’ windings. The detection of these compounds in the insulating oil of transformers is essential to investigate the ageing of the oil-paper system in order to avoid failures. To this aim a non-conventional surface plasmon resonance (SPR) platform in plastic optical fiber (POF) has been proposed by our group for the detection of 2-FAL in transformer oil. Besides a biomimetic receptor has been introduced, i.e. a molecularly imprinted polymer (MIP), which gives a noticeable selectivity to the device and many advantages with respect to the biological counterparts. Here the study has been extended to the very similar compound 5-HMF, in order to better establish the selectivity of the device in the particular oil matrix considered. To this aim the analysis of the binding interactions of two furanic compounds with the molecularly imprinted polymer (MIP) has been performed. The high sensitivity and the low amount of binding MIP material required for the investigation are two advantageous aspects of the SPR method to investigate the interactions of 2-FAL and 5-HMF with MIPs. Tests have been carried out on the same SPR-MIP sensor exposed to different 5-HMF and 2-FAL concentrations in the insulating oil by recording the plasmon resonance wavelength shift with the concentration of the furanic compounds. The results show that the 2-FAL has a higher affinity than 5-HMF for the specific MIP, demonstrating the good selectivity of the MIP receptor even in the very complex matrix considered.