Supercapacitors: The Innovation of Energy Storage

In addition to the accelerated development of standard and novel types of rechargeable batteries, for electricity storage purposes, more and more attention has recently been paid to supercapacitors as a qualitatively new type of capacitor. A large number of teams and laboratories around the world are working on the development of supercapacitors, while their ever-improving performances enable wider use. The major challenges are to improve the parameters of supercapacitors, primarily energy density and operating voltage, as well as the miniaturization, optimization, energy efficiency, economy, and environmental acceptance. This chapter provides an overview of new techniques and technologies of supercapacitors that are changing the present and future of electricity storage, with special emphasis on self-powering sensor and transmitter systems. The latest achievements in the production, modeling, and characterization of supercapacitor elements (electrode materials, electrolytes, and supporting elements) whose parameters are optimized for long-term self-supply of low power consumers (low voltage, high energy density, and low leakage current, etc.) are considered

Identification of Degrading Effects in the Operation of Neighboring Photovoltaic Systems in Urban Environments

As photovoltaics technologies have emerged as one of the most promising renewable energy resources in urban environments, monitoring and maintaining of such systems have gained significance. In order to support reliable system operation during the projected in-field operation lifetime, effective strategies for identifying potential problems in photovoltaic systems operation are needed. In this paper, novel methods for the identification of degrading effects in the operation of neighboring photovoltaic systems are presented. The proposed methods are applicable for identifying panel aging properties, soiling effects, and the operation of photovoltaic systems under different shading scenarios. Since the proposed methods are based on the cross-correlation of the operation of neighboring systems, they are particularly suitable performance assessment in urban environments. The proposed identification methods are integrated according to the adopted fog computing model, providing a scalable solution capable of uniform integration into the distributed applications for monitoring and maintenance of photovoltaic systems in urban areas. The details regarding the implementation of the identification methods in the form of data processing services and service operation and dependencies are also provided in this paper. The identification methods, integration concept, and related service operation are verified through the presented case study

Developing Relative Humidity and Temperature Corrections for Low-Cost Sensors Using Machine Learning

Existing government air quality monitoring networks consist of static measurement stations, which are highly reliable and accurately measure a wide range of air pollutants, but they are very large, expensive and require significant amounts of maintenance. As a promising solution, low-cost sensors are being introduced as complementary, air quality monitoring stations. These sensors are, however, not reliable due to the lower accuracy, short life cycle and corresponding calibration issues. Recent studies have shown that low-cost sensors are affected by relative humidity and temperature. In this paper, we explore methods to additionally improve the calibration algorithms with the aim to increase the measurement accuracy considering the impact of temperature and humidity on the readings, by using machine learning. A detailed comparative analysis of linear regression, artificial neural network and random forest algorithms are presented, analyzing their performance on the measurements of CO, NO2 and PM10 particles, with promising results and an achieved R2 of 0.93–0.97, 0.82–0.94 and 0.73–0.89 dependent on the observed period of the year, respectively, for each pollutant. A comprehensive analysis and recommendations on how low-cost sensors could be used as complementary monitoring stations to the reference ones, to increase spatial and temporal measurement resolution, is provided

Building Low-Cost Sensing Infrastructure for Air Quality Monitoring in Urban Areas Based on Fog Computing

Because the number of air quality measurement stations governed by a public authority is limited, many methodologies have been developed in order to integrate low-cost sensors and to improve the spatial density of air quality measurements. However, at the large-scale level, the integration of a huge number of sensors brings many challenges. The volume, velocity and processing requirements regarding the management of the sensor life cycle and the operation of system services overcome the capabilities of the centralized cloud model. In this paper, we present the methodology and the architectural framework for building large-scale sensing infrastructure for air quality monitoring applicable in urban scenarios. The proposed tiered architectural solution based on the adopted fog computing model is capable of handling the processing requirements of a large-scale application, while at the same time sustaining real-time performance. Furthermore, the proposed methodology introduces the collection of methods for the management of edge-tier node operation through different phases of the node life cycle, including the methods for node commission, provision, fault detection and recovery. The related sensor-side processing is encapsulated in the form of microservices that reside on the different tiers of system architecture. The operation of system microservices and their collaboration was verified through the presented experimental case study

Voltage Controlled Power Characteristics of a Custom Made Laser Diode Assembly

Construction and characterization of a simple but flexible, low cost diode laser system for the excitation of carbon quantum dots as a treatment method for ocular cancers is reported. System was designed to deliver maximal amount of laser diode radiant flux to the eye of the test mice using optical cable. Detailed electronic circuit layouts of the laser diode voltage controller, supplying maximum 3 V of voltage with 20 mV resolutions, and functional description of all other components (optical cable delivery system and supporting console) are given. The system features visual signalization when the laser diode module is powered. Since the laser diode radiant flux is directly dependent on the input voltage, measurement was performed in order to obtain approximation function of this dependency. Purpose of this function is to eliminate radiant flux measurement before each experiment which requires controlled conditions.22nd Telecommunications Forum Telfor (TELFOR), Proceedings, Nov 25-27, 2014, Belgrade, Serbi

Voltage Controlled Power Characteristics of a Custom Made Laser Diode Assembly

Construction and characterization of a simple but flexible, low cost diode laser system for the excitation of carbon quantum dots as a treatment method for ocular cancers is reported. System was designed to deliver maximal amount of laser diode radiant flux to the eye of the test mice using optical cable. Detailed electronic circuit layouts of the laser diode voltage controller, supplying maximum 3 V of voltage with 20 mV resolutions, and functional description of all other components (optical cable delivery system and supporting console) are given. The system features visual signalization when the laser diode module is powered. Since the laser diode radiant flux is directly dependent on the input voltage, measurement was performed in order to obtain approximation function of this dependency. Purpose of this function is to eliminate radiant flux measurement before each experiment which requires controlled conditions.22nd Telecommunications Forum Telfor (TELFOR), Proceedings, Nov 25-27, 2014, Belgrade, Serbi

Attitudes of Serbian food producers with quality and safety control systems towards business environment

The implementation of quality and safety control systems, e.g. Hazard Analysis and Critical Control Point (HACCP), is becoming compulsory for all companies whose aim is to export products to world market and to the countries that are members of the World Trade Organisation (WTO). Food safety is one of the basic requirements for the placement of products into the EU1 market. Moreover, domestic consumers are increasingly aware of the importance of food safety and quality.Implementation of the new rules means companies will be faced with new challenges. From the companies’ perspectives the basic idea is that the state creates a competitive environment and clear rules for the business operation. There is a lack of research on the attitudes of food producers towards business environment in the Republic of Serbia. Therefore this paper presents partial results of research, the objective of which was to determine attitudes of producer companies regarding state regulations and the business climate. The research was conducted in the framework of the project TR31034 financed by the Serbian Ministry of Education and Scienc