Varistors are commonly used elements which protect power supply networks against high-voltage surges or lightning. Therefore, quality and endurance of these elements is important to avoid losses when an expensive laboratory equipment would not be protected from random overvoltages. Additionally, excessive leakage currents generate serious costs due to high energy consumption. The paper presents shortly properties of varistors that comprized different ZnO grain types and can have various quality which changes continuously during exploitation (due to exposition to overheating and overvoltage pulses). Therefore, it is important to monitor varistors during their ageing (causing changes within their microstructures). A few methods of varistor property diagnosis were considered and compared with the methods currently applied in laboratory or industry applications. A new measurement (diagnostic) system that can monitor varistors during ageing and can be widely applied in power networks is presented. The proposed system fulfills requirements of the industrial customers which demand various methods for power line protection. The proposed system can be simply developed into a more advanced wireless diagnostic system of long power supply lines.

This article focuses on the study of the influence of remelting and subsequent natural and artificial ageing on the structure of recycled AlSi9Cu3 alloy with increased iron content. The assessed changes in eutectic silicon and iron-based intermetallic phases were carried out using optical and scanning electron microscopy. The degradation of the eutectic silicon morphology due to remelting occurred only at the highest numbers of remelting. The effect of remelting the investigated alloy, which is accompanied by a gradual increase in wt. % Fe, began to manifest significantly through a change in the length of the ferric phases after the fourth remelting. As expected, the artificial ageing process has proven to be more effective than natural ageing. It has led to a change in the eutectic silicon morphology and has been beneficial in reducing the lengths of adverse ferric phases. The use of alloys with higher numbers of remelting, or with greater “contamination”, for the manufacture of shape-challenging castings is possible when using a suitable method of eliminating the negative factors of the remelting process. The results of our investigation show a suitable method of the above elimination the application of heat treatment T5 – via artificial ageing.

The present paper is comparing the results of research studies carried out for three road acoustic screens of different design and different number of damping layers. For the tests, we selected timber or steel screens with a traditional multilayer structure and also one innovative type of simplified design. With respect to particular panels, their sound absorption properties were investigated in the reverberation chamber after they had been subjected to simulated weathering. In the process, two screens were subjected to the aging tests of 50–500 cycles in a special climatic chamber, and the innovative screens were subjected to 1000 cycles. The procedure was repeated every 50 or 100 cycles in order to obtain the changes of acoustic characteristics. The changes taking place in the absorbing material were also investigated with the use of scanning electron microscopy method (SEM). Basing on the obtained results and on the statistical analysis, the capability to maintain acoustic properties by the panels during their service life in natural conditions was estimated. For that purpose, linear statistical models were worked out, which were then applied to estimate the value of the single number sound absorption coefficient after successive aging cycles as well as the predicted time periods of acoustic class changes.

Hard bitumens are used in the construction industry primarily in it’s unmodified form, for instance for the production of the so-called traditional roofing felt. Due to the low price of these types of membranes, the use of a popular but expensive modifying agent, SBS copolymer, is not justified economically. Research carried out by the authors has shown that chemical organic compounds belonging to a group of imidazolines may potentially be used as much cheaper bitumen modifier. It was demonstrated that a new type of modifier based on oleic imidazoline, developed by the authors, has a significant impact on improving the physical properties of bitumen. The use of this modifier results in a significant increase in the bitumen plasticity range, both before and after laboratory ageing .In addition, there was a considerable increase of bitumen’s resistance to aging. Its use can help improve the quality and durability of popular waterproofing products manufactured with the use of hard bitumen.

Assessing the level of metallurgical and foundry technology in prehistoric times requires the examination of raw material finds, including elongated ingots, which served as semi-finished products ready for further processing. It is rare to find such raw material directly at production settlements, but Wicina in western Poland is an exception. During the Hallstatt period (800-450 BC), this area, situated along the middle Oder River, benefited from its favorable location in the heart of the Central European Urnfield cultures and developed networks for raw material exchange and bronze foundry production. Numerous remnants of casting activities, such as clay casting molds, casting systems, and raw materials, have been discovered at the Wicina settlement. This article aims to provide an archaeometallurgical interpretation of raw material management and utilization by prehistoric communities during the Early Iron Age. To achieve this, a collection of 31 ingots from the defensive settlement in Wicina, along with two contemporary deposits from Bieszków and Kumiałtowice, both found within a 20 km radius of the stronghold, were studied. Investigations were conducted using a range of methods, including optical microscopy(OM), scanning electron microscopy (SE M), energy-dispersive X-ray spectroscopy (SE M-EDS), X-ray fluorescence spectroscopy (ED-XRF), powder X-ray diffraction (PXRD), AAS and ICP-OES spectrometer. The significance of ingots is examined in the context of increasing social complexity and the rising popularity of bronze products, which necessitated diversified production and a demand for raw materials with different properties and, consequently, different chemical compositions.

The most important parameters which predetermine mechanical properties of a material in aspects of suitability for castings to machinery components are: tensile strength (Rm), elongation (A5, hardness (HB) and impact strength (KCV). Heat treatment of aluminum alloys is performed to increase mechanical properties of the alloys mainly. The paper comprises a testing work concerning effect of heat treatment process consisting of solution heat treatment and natural ageing on mechanical properties and structure of AlZn10Si7MgCu alloy moulded in metal moulds. Investigated alloy was melted in an electric resistance furnace. Run of crystallization was presented with use of thermal-derivative method (ATD). This method was also implemented to determination of heat treatment temperature ranges of the alloy. Performed investigations have enabled determination of heat treatment parameters’ range, which conditions suitable mechanical properties of the investigated alloy. Further investigations will be connected with determination of optimal parameters of T6 heat treatment of the investigated alloy and their effect on change of structure and mechanical/technological properties of the investigated alloy.

Samples of CdTe single crystals which are used as radiation detectors were periodically measured during a long time interval with different values of an applied voltage. The samples were also periodically exposed during long time periods to high temperatures of 390 K and to rapid changes of temperature from 300 K to 390 K. After 1.5 years of measurements we observed ageing of the samples which resulted in deterioration of their transport characteristics. The resistance of the samples increased significantly and current-voltage characteristics were unstable in time. Noise spectroscopy showed that low frequency noise can be used for detection of CdTe sample ageing as its spectral density increases significantly comparing to the 1/f noise of a high quality sample

The paper presents the microscopic and mechanoacoustic study of degradation processes of the porcelain material C 130 type.

This kind of material is used in the production of the most durable and reliable electrotechnical elements. Raw material composition of the studied porcelain was modified. This had an impact on the inner properties, cohesion and – in consequence – on operational properties of the material.

Using mechanical-acoustic and microscopic methods of testing of small-size samples that were subjected to compression, it was possible to distinguish successive stages of degradation of the porcelain structure. These stages were generally typical of the porcelain materials. In the authors’ opinion, they are connected to the ageing process happening over many years of work under operating conditions.

Optimization of composition and technological properties – important during technological processes – resulted in a slight decrease in inner cohesion of the porcelain. When compared to the reference material – typical domestic C 130 material, mechanical strength was somewhat lower. Carried out investigations proved that resistance of the investigated material to the ageing degradation process – during long term operation – also decreased. The improvement of technological parameters and the reduction in the number of defective elements occurred simultaneously with some decrease in the operational parameters of the material. To restore their initial high level, further work is needed to optimize the raw material composition of the porcelain.

In the era of an aging society, age friendly cities planning is gaining in importance. Due to the low mobility of these people, it is important to plan their immediate living environment, ensuring access to facilities and areas that meet the basic needs of this special group of urban space users. The paper analyzes the potential accessibility of older people to green areas, sports and recreation facilities, service and commercial facilities, culture and health care facilities, and public transport stops, in order to delimit problem areas characterized by functional and spatial deficits in this area. In addition, the level and quality of accessibility of older people to the abovementioned elements of development.

What do biological powerhouses look like? How do they work? Why does generating a single “dose of energy” demand a highly complicated process? Why do seeds age? Answers to all these questions are to be found in one of the most complex cellular organelles: the mitochondrion.

Studying ancient human DNA can help us better understand the early histories of states and nations – says Prof. Marek Figlerowicz from the PAS Institute of Bioorganic Chemistry in Poznań.

The variety of forms of Medieval landscapes reflects the political and social situation of European territories in the period between the fifth and the fifteenth century. From a contemporary point of view, we are dealing with a number of distinct types of landscape objects in European areas, such as 1. Medieval fortresses (castles); 2. residential settlements, including cities, towns and villages; 3. abbeys and smaller monasteries; 4. churches in open landscapes and pilgrimage centres; 5. areas of agriculture; 6. garden compositions; 7. specifically Polish relics of the past such as early-Medieval gords.

The aim of this article is to draw attention to the growing phenomenon of working in retirement in the light of active and successful aging concepts. The change in attitudes towards aging, work and retirement among Poles can be seen as a kind of social process that has been ongoing since the early 1990s. Nowadays, more and more people of retirement age, anxious to remain active and independent for as long as possible, are delaying the moment of professional deactivation. The article presents the partial findings of research conducted by the author. The purpose of the qualitative study ”Attitudes towards retirement and type of reflexivity as determinants of positive aging” was to characterize the motivations for career continuation and the benefits of prolonged professional activity among people over 60. The findings—concerning participants considered professionals (n = 20) according to the International Standard Classification of Occupations ISCO-08—suggest that continuing one’s career after reaching retirement age can be considered one of the strategies for achieving successful aging.

This article is devoted to the subject of age and the elderly in the Middle Ages, and the manner of viewing elderly people in those times. The author uses Jan Długosz’s Annals, books 9–12, as his basic source. His analysis concentrates on the following questions: Whom did the Polish historian consider worthy of remembrance in his Annals? How did he describe those figures? What words did he use to describe the phenomenon of age or aging? The author analyses the Latin terms used to describe specific older persons, and also presents the perceptions of older women, older men, and elderly people as a group. An attempt is made to answer the question of whether old age was a period of well-being and prosperity in medieval times.

Local and Regional Policy in the Light of Depopulation – Example of Silesian Voivodeship. Decreasing number of population along with demographic ageing create significant developing challenges in the labour market, in housing, social infrastructure, education and in many other areas. This applies in particular to the areas in which significant intensification of depopulation is already observed or expected to occur. Therefore, it should be considered when local and regional policies are being created, and it should be reflected in development strategies formulated for each area. The goal of the article is to determine whether the formulated development strategies reflect the real needs arising from the observed social processes and how precisely they reflect local and regional policies. This problem is illustrated by the example of the Silesia Voivodeship.

Changes in the size and the age structure of a population have a great impact on an economy, especially on national savings and capital flows. Poland’s population, although still relatively young when compared to other developed countries, is expected to experience accelerated ageing and decline in forthcoming decades. In this paper, we assess the effects of these processes for Polish economy. Using an open-economy OLG model with demographic shocks and a variable retirement age, we simulate dynamics of real interest rates, main macro aggregates as well as net foreign assets to GDP. We show that rapid ageing will reduce the interest rate gap between Poland and the developed countries by 1.3-2 p.p. We also document a strong positive relationship between interest rates and the retirement age and find that the decline in the interest rate in Poland is primarily driven by the surviving probability shock

A crucial feature in health monitoring of already existing structures is to be seen particularly in identifying their topical internal structural parameters and controlling their remaining bearing capacity in the course of ageing processes. This is commonly carried out by measuring the deformations/strains caused by test-loading and calculating the parameters on the basis of the metered data.

In the case of elastic response of materials, the information on the parameters is directly related to the time of measurement; in the case of visco-elastic response, however, the history of the time-depending structural response during the period between initial loading and initiating the test-measurements is generally unknown. The problem exists, then, to separate the superimposed strains due to the existing state and to the test-load. For solving the problem, at first the relevant relations between stress/strain and the visco-elastic parameters are considered. Then a procedure will be described how to determine the strain state owing to the test-load only and to calculate the relevant parameters as functions of time. According to the principle of time-shift invariance, the results describe the time-depending response of the viscoelastic material, no matter at which time the loads are applied.

The presented method will be illustrated by two simple but instructive examples.

Searching and exploring the motives of continuing in the profession may be an important objective of efforts undertaken by researchers and people directly responsible for the organization and quality of work. Identifying the needs and expectations of the employee is an important element of her/his adaptation in the work environment. Because the age of life is one of the factors affecting the perception of the world and work, in this article motives of continuing professional activity in group of special educators are described in the age of life context.

The chief purpose of this study is to investigate the process of adsorption of heavy metals in sands containing microplastics due to aging and bacterial culture. For this purpose, first, the experiment’s conditions were determined by reviewing previous studies and examining the effects of factors on the duration of bacterial culture and UV radiation. Finally, the test conditions were determined as follows: 25 g of adsorbent in 250 ml solution containing 50 mg/l of lead, cadmium, copper, zinc, chromium, and nickel, 750 micrograms of microplastic, bacterial culture time two days, aging time with UV light 14 days. Results of the study show that the addition of virgin microplastics has little effected on increasing the adsorbent strength, except in the case of nickel whichreduces adsorption strength. The aging process increases the absorption of all studied metals by up to 60%. Bacterial culture without an aging process reduces the absorption of nickel and cadmium. Simultaneous use of bacterial culture and aging increases the adsorption power by up to 80% for all metals.

Humidity is probably the most important abiotic factor influencing life cycles, distribution, survival, and population dynamics of stored product pests. Although most of these pests can complete their life cycles in any given relative humidity, their prolonged development time, as well as decreased emergence rate and fecundity, have been well documented in several previous studies. In the present study, we evaluated the changes in energetic substances (lipids, soluble carbohydrates, glycogen, and proteins) accumulated in different life stages of larvae and adults of Tribolium castaneum in response to different relative humidity levels (5, 12, 22, 30, 45, and 65%). The results showed that young larvae were more susceptible to low relative humidity levels and desiccation stress. Larvae tended to accumulate higher proportions of lipids during earlier stages while their energy content shifted towards proteins with an increase in their age. Adult beetles experienced a significant decrease in their protein content immediately after they initiated reproduction. The importance of these fluctuations in the biology of the red flour beetles was discussed in detail.

Room temperature vulcanized (RTV) silicone rubber is widely used to prevent pollution flashover with its excellent hydrophobicity and hydrophobicity transfer. However, RTV coatings are at the risk of deterioration and failure in heavily polluted operating environment. In this paper, RTV coated insulators with different suspension heights operating in coal ash polluted areaswere sampled. Pollution degree, pollution composition and aging degree of coatings were tested. The result shows that the insoluble pollution contains Al(OH)3 filler precipitated from RTV coating, which indicates the aging of the RTV coating. The top surface coating is more affected by ultraviolet and rainwater than the bottom surface resulting in more serious degradation. As the pollution degree of the lower phase insulator is heavier than that of the upper phase insulator, the erosion effect of pollution on the RTV coating is more intense. The fillers and rubber molecules of RTV continuously precipitate into the pollution layer, leading to further aging. Therefore, the overall aging degree of the lower insulator coating is more serious than that of the upper insulator coating.

The stance of mysticism on language is located in the field of tensions between the fundamental inability to express the essence of God through the medium of language and the imperative, or the need, to talk about it. In the space betwixt and between, there extends mystic silence as a paradoxical, but effective way of communication and insight. Depending on individual mystics, whose selection from the Middle Ages to the Baroque is presented in the text, silence receives also various additional aspects.

This study aims to explore the effects of age across adult groups on selected aspects of language learning. To achieve the aim, a study was conducted at the Open University of University of Warsaw. It focuses on reasons for taking up learning, relative importance of individual skills, major difficulties, individual goals, emotions and self-assessed ability to learn. The assumption that adults represent a single age group is questioned and the results are interpreted in terms of practical implications for course design.

APNB (alkaline phenolic no bake), widely known as Alphaset is one of the major sand binder systems used in foundries to make molds and cores without application of heat or gas. This is a two part system comprising of a phenol-formaldehyde resin in alkaline medium as binder and range of esters of dibasic acids and/or polyhydric alcohols as hardeners.

Resin performance varies depending upon formulations. Major variables in formulations are mole ratio of phenol: formaldehyde, total alkali content, ratio of two alkalis (NaOH & KOH) and molecular weight of polymers i.e. chain length.

In present work, one mole ratio of phenol & formaldehyde has been chosen to prepare 8 resins with following details.

Table 1.

Physical and chemical properties of eight (fresh) resins, A to H

Properties	A	B	C	D	E	F	G	H
Viscosity at 30°C (mPs-a)	56	47	66	51	39	44	49	52
Na (%)	5.94	3.21	5.94	3.21	nil	2.73	nil	2.73
K (%)	nil	3.31	nil	3.31	7.18	3.87	7.18	3.87
Molecular weight	Low	Low	High	High	Low	Low	High	High
Gel Time at 121°C, mt-sec	27-0	29-30	24-0	30-0	30-0	27-30	26-30	26-0
Moisture (%)	52.43	52.42	53.01	53.75	55.58	54.12	51.61	54.03
Non-volatile Content (%)	48.74	47.25	49.10	49.35	47.63	47.32	48.06	48.29
Specific Gravity	1.182	1.177	1.183	1.180	1.172	1.184	1.178	1.188
Free Phenol (%)	0.47	0.42	0.44	0.43	0.37	0.27	0.41	0.20

Properties of these 8 formulations have been studied for strength and viscosity over a period of 12 weeks in 4 week interval.

Attempt has been made to develop a simple test for simulating hot & retained strength of molds in laboratory. Process followed for chasing hot and retained strength is described under clause 2.

With more and more understanding of the chemistry of alphaset system in last three & half decades it has been possible to identify role of variables contributing towards specific properties vis a vis developing tailor made formulations to fulfill requirements of individual foundries right from mold making to de coring.