The protection of Polish architectural heritage in the former eastern borderlands, accomplished through the conservation and technical securing of historical structures, constitutes one of the main programmes that are implemented by the Ministry of Culture and National Heritage. Currently, many Polish historical buildings in the former eastern borderlands are in a very bad technical condition. The load-bearing systems of these elements, as well as elements of their finish, require immediate emergency securing work. The basic steps that precede conservation work are emergency structural works, which guarantee the durability and stability of the entire historical substance. The specifics and complexity of the problem of the failure of historical buildings often demands an in-depth analysis of a series of factors that are difficult to measure and which are responsible for the cause and effect relationship during the early stage of the technical evaluation of a structure. The analyses of failures of numerous historical structures, for instance that were carried out by the authors, have become the inspiration for the search for effective methods of analysis that would allow for an in-depth analysis of the causes and effects of the failures in question. The DEMATEL method (Decision Making Trial and Evaluation Laboratory) that has been presented in this work, and its fuzzy extension, has lately become one of the more popular methods used in the cause-and-effect analysis of various phenomena. The authors demonstrated how this method works on the example of the evaluation and securing of the load-bearing system of the XVII Collegiate church of the Holy Trinity in the town of Olykha in the Volhynskiy Oblast, Ukraine.
The authors describe the program undertaken at the Warsaw University of Technology (WUT), aimed at developing mobile aerodynamic laboratories to be used for investigation into aerodynamic properties of airfoils or lightweight propulsion systems - in natural scale and in natural atmosphere. The enterprise was named the EB-program, and has both: research and educational aspects; in all phases of the program (i.e. design, manufacturing and testing) the WUT students are involved. As the result of work, three mobile aerodynamic laboratories were build: EB-1 - which was tested on the car roof, EB-2 - unique flying laboratory based on the PW-6 glider, and EB-3 - a new generation of flying wind tunnel to be used on the AOS-71 glider, which currently is under preparation to the flight tests. The authors present in detail the measurement systems and procedures supported by the Lab View software.
This paper concerns an approach to model the ledger-stand joints of modular scaffolds. Based on the analysis of the working range of the ledger (represented by a linear relationship between load and displacement), two models of the ledger-stand joint are analysed: first – with flexibility joints and second – with rigid joints and with a transition part of lower stiffness. Parameters are selected based on displacement measurements and numerical analyses of joints, then they are verified. On the basis of performed research, it can be stated that both methods of joint modelling recommended in this paper, can be applied in engineering practices.
The paper presents numerical and experimental research on glulam delamination in a double lap connection with predominant shear stresses. Laboratory tests and wide literature survey enabled to determine timber and glue joint parameters. Cohesive zone theory, generally used for epoxy matrix and fiber reinforced composites, was adopted to modelling glue layer delamination in glulam elements. Numerical models were validated with laboratory tests.
Reliable estimation of geotechnical parameters is often based on
reconstruction of a complete loading process of subsoil on a specimen in
laboratory tests. Unfortunately laboratory equipment available in many
laboratories is sometimes limited to just a triaxial apparatus
–
the use of which generates diffi culties whenever a non-axisymmetric
problem is analysed.
The author suggests two simple operations that may be done to improve the quality of simulation in triaxial tests. The fi rst one is based on the use of triaxial extension along the segments of the stress path p’-q-θ for which the Lode’s angle values are positive. The second one consists in a mod-ifi cation of the equivalent stress value in such a way that the current stress level in the specimen complies with results of FEM analysis.
The use of shredded tyre in civil engineering applications is a significant potential end use market. The reuse of tyre chips may not only address growing environmental and economic concerns, but also help to solve geotechnical problems associated with low shear strength. The purpose of this paper is to investigate the properties of tyre chips and tyre chips – sand mixture, and to find the mixture with the highest shear strength. In this study, an experimental testing program was undertaken using a large – scale triaxial apparatus with the goal of evaluating the optimum percentage of tyre chips in sand. The effects on shear strength of varying percentage of tyre chips and varying confining pressure were studied. Tyre chips content was suspected to have influence on stress – strain and volumetric strain behaviour of the mixture. Some tests were conducted to check the influence of number of used membranes, of saturation and compaction, on sample properties.
Introduction: Effective and safe anesthesia for rodents has long been a leading concern among biomedical researchers. Intraperitoneal injection constitutes an alternative to inhalant anesthesia.
Purpose: The aim of this study was to identify a safe, reliable, and effective anesthesia and postoperative analgesia protocol for laboratory rats exposed to painful procedures.
Material and methods: Twenty-seven female Wistar rats in an ongoing study that required surgery were randomized into groups for three different intraperitoneal anesthesia protocols and three different analgesia regimens. The anesthesia groups were (1) medetomidine + ketamine (MK), (2) ketamine + xylacine (KX), and (3) fentanyl + medetomidine (FM). Three analgesia groups were equally distributed among the anesthesia groups: (1) local mepivacaine + oral ibuprofen (MI), (2) oral tramadol + oral ibuprofen (TI), and (3) local tramadol + oral tramadol + oral ibuprofen (TTI). A core was assigned to measure anesthesia (0-3) and analgesia (0-2) effectiveness; the lower the score, the more effective the treatment.
Results: The mean MK score was 0.44 versus 2.00 for FM and 2.33 for KX. Mean score for analgesia on the first postoperative day was TTI (4.66) TI (9.13), and MI (10.14). Mean score 48 hours after surgery was TTI (3.4), TI (6.71), and MI (9.5). These differences were statistically significant.
Conclusion: MK was shown to be a reliable, safe, and effective method of anesthesia. The TTI analgesia regimen is strongly recommended in light of these results.
This paper presents the results of preliminary tests for estimating the modulus of elasticity of wooden beams from firs reinforced with PBO fiber mesh. The tests were carried out in the Materials Strength Laboratory at the Kielce University of Technology in Kielce, Poland with PN-EN 408:2004. The wooden elements were subjected to a four-point bending test with the aim of estimating the elastic modulus when bending, assuming the loading velocities of the loading forces of 5 mm/min. The obtained results show a significant increase in the load-bearing capacity of beams reinforced with PBO mesh.
Five years ago, the Act on the protection of animals used for scientific or educational purposes entered into force. It is the implementation of Directive 2010/63/ EU into the Polish legal system. During the work on the Directive, most scientists were convinced that the previous Act on animal experiments of 2005 was in line with the new EU law and only minor modifications would be necessary. Legislators, however, decided to create a completely new legal act. Already at the time of the Act's creation, the scientific community made many critical comments regarding the law. Significant discrepancies between the Directive and the proposed provisions of the Act were far more stringent, and in many places with imprecise provisions which could have resulted in difficulties in conducting research using animals. Unfortunately, most of the postulates of the scientific community were not considered at that time. What does the Act look like 5 years after its adoption? Instead of a transparent and balanced law modeled on the EU Directive, which provides real protection for experimental animals, while safeguarding the intellectual rights of animal testing units, a patch of underdeveloped, sometimes mutually exclusive provisions has been issued. Instead of raising the welfare of the animals used for research to a higher level, it significantly increased the costs of operating research units and increased bureaucracy. Instead of rationalizing the system of issuing consents for research, it has been weakened and entangled in administrative and legal disputes without the provision of basic administrative facilities. Instead of increasing the international mobility of scientists and technicians working with experimental animals, the implementation of the law created a training “system” that is not recognized in any other EU country. In the light of the 5-year experience of the scientific community and the expert part of the composition of local ethics committees, we postulate to introduce a number of significant changes to the act so that its amended version actually ensures animal protection, respect for researchers and returns to the current of European legislation.
A special Slag-Prop Cu database has been developed to archive data from laboratory and industrial tests related to post-reduction slags. In
order to enrich the data areas, it was decided to design a system for measuring the temperature of the liquid slag and its viscosity. Objectives
of research work are to gather information on the properties of post-slags such as the temperature of liquid slag and its viscosity. The
discussed issues are especially important in the foundry practice. Designed research stand and using of database applications can greatly
facilitate the work of metallurgists, foundrymen, technologists and scientists. The viscosity measurement was developed and presented
earlier. The author's analytical methodology was supplemented by a thyristor measuring system (described in the article). The system
temperature measurement can be performed simultaneously in 3 ways to reduce the measurement error. Measurement of the voltage mV -
using the Seebeck effect can be measured throughout the entire range of thermocouple resistance, up to 1300 °C. Direct temperature
measurement ⁰C - measurement only below 1000 ⁰C. Additional measurement - the measurement can also be read from the pyrometer set
above the bath. The temperature and the reading frequency depend on the device itself. The principle of measurement is that in a molten
metal / slag crucible, we put a N-type thermocouple. The thermocouples are hung by means of a tripod above the crucible and placed in a
crucible. The thermocouple is connected to a compensating line dedicated to this type of thermocouple. The cable is in turn connected to a
special multimeter that has the ability to connect to a computer and upload results. Temperature measurement can be performed
simultaneously in 3 ways to reduce the measurement error. The Sn-Pb alloy has been subjected to testing for proper operation of the device.
In this foot should be observed the supercooling of the liquid, which initiates the crystallization process and in which latent heat begins to
exude raising the temperature until the coagulation temperature is reached.
In recent years, many scientific and industrial centres in the world developed virtual reality systems or laboratories. At present, among the most advanced virtual reality systems are CAVE-type (Cave Automatic Virtual Environment) installations. Such systems usually consist of four, five, or six projection screens arranged in the form of a closed or hemi-closed space. The basic task of such systems is to ensure the effect of user “immersion” in the surrounding environment. The effect of user “immersion” into virtual reality in such systems is largely dependent on optical properties of the system, especially on quality of projection of three-dimensional images. In this paper, techniques of projection of three-dimensional (3D) images in CAVE-type virtual reality systems are analysed. The requirements of these techniques for such virtual reality systems are outlined. Based on the results of measurements performed in a unique CAVE-type virtual reality laboratory equipped with two different 3D projection techniques, named Immersive 3D Visualization Lab (I3DVL), that was recently opened at the Gdańsk University of Technology, the stereoscopic parameters and colour gamut of Infitec and Active Stereo stereoscopic projection techniques are examined and discussed. The obtained results enable to estimate the projection system quality for application in CAVE-type virtual reality installations.
This paper presents a design of a tracked in-pipe inspection mobile robot with an adaptive drive positioning system. The robot is intended to operate in circular and rectangular pipes and ducts, oriented horizontally and vertically. The paper covers a design process of a virtual prototype, focusing on track adaptation to work environment. A mathematical description of a kinematic model of the robot is presented. Operation of the prototype in pipes with a cross-section greater than 210 mm is described. Laboratory tests that validate the design and enable determination of energy consumption of the robot are presented.