APLICATION OF REGRESSION ANALYSIS IN FEASIBILITY STUDIES OF CONSUMER CONNECTION TO DISTRICT HEATING SYSTEMS

Nowadays, both globally and in Europe, and nationally, there is a tendency to promote district heating systems to the detriment of individual ones to heat dwellings in urban areas. The need to develop the DHSs is indisputable considering the topicality of global warming, the depletion of the primary energy resources and the energy efficiency trend. This article presents the method of applying regression analysis in feasibility studies for the projects of new heat consumers connection to the district heating system (hereinafter – DHS) or previously disconnected consumers reconnection via individual heating points (hereinafter – IHP) when the necessary investments are to be borne by the DHS operator, and the thermal energy is produced in cogeneration. At the same time, it is demonstrated that there is a direct and linear correlation between fuel consumption and electricity and heat produced in cogeneration at CHP plant.

DEVELOPMENT OF IoT BASED SMART INVERTER FOR ENERGY METERING AND CONTROL

Insufficient power generation has facilitated the search for alternative power generation, as the world is gradually making the transition to renewable green energy sources as a replacement for fossil fuels and other conventional power generation methods that causes environmental pollution. One of these methods is the use of solar energy for electricity generation through the use of the photovoltaic solar inverter which harnesses the power from the sun to generate electricity. The inability of electricity distributors to provide enough and sustainable power supply for homes and businesses, coupled with the need to live a smart life has made humans sort for an easier control method of electricity generation and usage. Hence, this research presents a smart voice and mobile application control modular inverter integrated with a smart metered energy distribution system, which equally distributes power amongst the users for effective and smart energy usage. A test of applied load on the inverter as compared to normal electricity usage deduced an 8% error rate giving a 92% accuracy for the inverter. The mobile app was tested for both online and offline usage and a 67% accuracy was deduced as the overall accuracy of the software. This gives an inference that the system can be fully operated by a user in the luxury of their comfort. For smart meter monitoring and energy allocation, 93.33% and 96.8% accuracy and precision were achieved respectively. This research makes the usage of green energy more efficient with its feature which allows for equal distribution of energy. The system also helps prevent energy theft or misuse by providing only the proper user with alerts and administrative control.

ALGORITHM FOR SELF-TUNING THE PID CONTROLLER

An algorithm for self-tuning the PID controller to the second order systems is proposed in this paper. The proposed self-tuning procedure was developed according to the maximum stability degree criterion, the criterion that permits to achieve the high stability degree, good performance and robustness of the system. According to the proposed algorithm, the controller can be tuned according to the parameters that characterize the process and they can be determinate from the experimental response of the open loop system. To demonstrate the efficiency of proposed procedure of self-tuning the PID controller, the computer simulation was performed and the obtained results were compared with Haeri’s method, maximum stability degree method with iterations and parametrical optimization method. According to the developed algorithm, it was performed the control of the thermal regime in the oven.

GENERIC ALGORITHM SOLUTION IN ESTIMATION OF THE IRON ABSORPTION POTENTIAL FROM COMPLEX SCHOOL MEALS

New analytical tools to study iron bioavailability are proposed in this article. An algorithm was devised to predict dietary iron abortion from school meals based on the contents of dietary factors that have the ability to promote or inhibit heme or non-heme iron absorption. The highest absorption rate of iron from representative meals was observed in the presence of ascorbic acid (27,73%) or meat ingredients (27,70%), and the lowest absorption rate – in the presence of Ca (12,40%), tannins (5,83%) and polyphenols (5,36%). Relationships between quantities of total iron intake from foods (dialyzable iron, in vitro assay) and the value of nutritional factors in those are described as exponential equations allowing calculations at any stationary state. In elaborated formula the rate of iron absorbance can be predicted considering one, two or three nutritional factors at the same time. The results emphasize the fact that it is important to understand the meal composition for the correct estimation of iron bioavailability.

SOME PARTICULAR ASPECTS OF THE AUTOMOTIVE INDUSTRY CONNECTORS

Electrical connectors are very sensitive parts in an electronic system. The actual meaning of reliability and the problems associated with determining it, are often not right understood. The paper presents some particular aspects of the automotive industry connectors’ i.e. fretting, fretting corrosion prevention, aluminium connections. The performance factors governed by the operating conditions and design-technology factors determined by the manufacturing characteristics of a contact unit were analyzed.

THE INFLUENCE OF DEPENDENCES OF PSYCHOPHYSIOLOGICAL CHARACTERISTICS OF DRIVERS

The article analyzes the "man-machine-environment" system in relation to the psychophysiological characteristics of the driver - "human operator". The methods of diagnosing the psychophysiological characteristics of drivers were analyzed. The dependencies between the parameters of psychophysiological characteristics were established: complex visual-motor reaction and emotional stability (Pearson correlation coefficient r = -0.7), as well as the correlation between emotional stability and the level of perception of speed and distance (r = 0.5). The psychophysiological characteristics at different stages of the driving experience were revealed and practical recommendations were formulated for their development.

A CASE STUDY ABOUT DEGRADATION OF THE BUILDINGS AND THEIR BUILDINGELEMENTS AS A RESULT OF CLIMATE CHANGE

The article deals with the problems of climate change and global warming, extreme climate phenomena, which present risk factors for the national economy, including construction. The causes that lead to the occurrence of the construction degradation phenomena are diverse and may be specific to improper exploitation, but also as a consequence of extraordinary natural phenomena or results from the humanity’s interrelationship with the environment. The degradation of the constructions is manifested by the gradual loss of the physical and functional qualities that characterize the aptitude for their exploitation, the degradation process manifesting itself starting from the contact surfaces of the constructions with the environment. Urban planning and the design of adequate infrastructure play an important role in minimizing the impact of climate change and reducing the risk to the human environment. The undertaking's measures, which will consider the potential impact of climate change on buildings, will provide opportunities for new markets for climate change-resistant technologies, machinery, materials, and products

COMPARATIVE ASSESSMENT OF COMPETENCE LEVEL OF TRANSPORT SYSTEM EXPERTS

The paper deals with the comparative assessment of competence level of transport system experts. The high level of competence of the experts is the premise to ensure the quality of the expertise of the systems insufficiently formalized from a mathematical point of view and characterized with a high degree of uncertainty. Six factors for assessing the competence of transport system experts were summarized. The values of the priority vector of the competence factors were established with the application of the Saaty algorithm and scale in nine points by the method of comparisons in pairs. The value of the concordance ratio of the experts' opinion for the prioritization matrix was calculated. The comparative competence coefficient of the experts in transport systems was calculated and the hierarchy of experts was established according to the value of the nominal coefficient.

CYBER SECURITY STRATEGIES FOR HIGHER EDUCATION INSTITUTIONS

Due to the large volume of data they manage, Higher Education Institutions (HEIs) are perfect targets for cyber attackers. University networks are open in design, decentralized and multi-user, making them vulnerable to cyber-attacks. The purpose of this research paper was to identify which is the recommended cyber security strategy and how comprehensive are these studies, within HEIs. The method proposed by Kitchenham was used, focused on the information community. Thus, the following results can be communicated: researchers recommend their own security strategies, because the standards analysed in the papers are not oriented on HEIs, and require important adjustments to be implemented. Most scientific papers do not describe risk management process. The implementation phases are also insufficiently analysed. The functions that the strategy addressed by HEIs should fulfill include identification, protection and detection. The validation methods used in the preimplementation and post-implementation phases are case studies and surveys. Most researchers recommend as final cyber security strategy IT Governance and security policies. The field of research has proved to be very interesting, the researches could contribute to the creation of a comprehensive cybersecurity strategy, focused on the specifics of HEIs, efficient, easy to implement and cost-effective.

PHYSICOCHEMICAL CARACTERISTICS OF UNRIPE APPLES

Apple plays an important role in human health. The unripe apples, after physiological falls and the agricultural operation "regulation of the fruit load", are not used for food. The use of agricultural organic waste is a current problem. In the presented paper was approached the possibility of valorification on these unripe fruits to obtain natural products. Were studied the unripe apples of 4 varieties: Coredana, Golden Rezistent, Rewena and Reglindis. The fruits were harvested during development at 45th, 58th, 71st, 84th and 97th days after the full bloom. It was determined physico-chemical indices in fruits extracts. During the ripening of fruits, the diameter and mass increased continuously, the moisture content does not change significantly, but the pH values of the apple pulp increased nonessential. Dry matter content and total sugar increased considerably as the fruits were growing. There are unexpected increases in dry matter around the 84th day after the full bloom. The acidity decreased during the fruit development. Sensory evaluation was also effectuated. The results obtained provide informations regarding the optimal use of the unripe apple varieties researched in order to process and obtain different products (especially natural acidifiers).