Because of the uneven colour of black locust wood, different technologies are used to change the colour, the bestknown being chemical and thermal treatments. Some of them affect the mechanical properties of wood, such as elasticity modulus, strength, durability. This study aims to compare the physical and mechanical properties of black locust wood control samples and treated wood samples with ammonia hydroxide, in terms of density profile, colour values (CIE L*, a*, b*), mechanical properties of samples subjected to static bending, viscous-elastic properties (storage modulus (E’), loss modulus (E”) and damping (tanδ)). Two types of ammonia-fuming treatment were applied on samples: first treatment T1-5% concentration of ammonia hydroxide for 30 days; second treatment T2-10% concentration for 60 days. The results highlighted the following aspects: the overall colour change in the case of the second treatment is 27% in comparison with 7% recorded for the control samples; the lightness and yellowness values are the most affected by the second ammonia treatment of black locust wood. The density increased with almost 20% due to ammonium fuming (10% concentration/60 days); in case of static bending, the elastic modulus (MOE) tends to decrease with increasing the exposure time to ammonium, but the modulus of rupture (MOR) increases with almost 17% and the breaking force increases too, with almost 41%. In the case of dynamic mechanical analysis, the temperature leads to different viscous-elastic behaviour of each type of samples.

Abstract-The central idea of this paper is the modeling andimplementation of a real-time dc servomotor angular speed control system with an unknown bounded uncertainty using a sliding mode observer (SMO) control strategy. We prefer to use a SMO in our approach due to its great potential in fault detection and isolation (FDI) of the actuators and sensor faults subjected frequently to several failures due to an abnormal change in their operating conditions or parameters. We use for this purpose the most suitable real time implementation tool MATLAB/SIMULINK software package. It provides special features for real time implementation by its extensions RealTime Workshop (RTW) and the Real-Time Windows Target (RTWT). The novelty of our paper is to prove in an extensive simulation MATLAB/SIMULINK frame the real time implementation potential of a most recently sliding mode observer (SMO) control strategy applied to a particular case study, namely for a dc servomotor angular speed control system. The proposed real-time Sliding Mode Observer (SMO) consists of an embedded nonlinear Sliding Mode Observer (SMO) with the dc servomotor actuator in an integrated control system structure to estimate its angular speed and armature current and to implement the sliding mode control law.

The influence of the piston effect in subway tunnels depends on a train speed, the geometry of a tunnel and a train, the types of air flow caused by mechanical ventilation and other variable characteristics. Tables and graphs of changes in air flows generated by the effect of the piston are presented depending on the speed of a train and the degree of fill rate of a tunnel. It is noted that the piston effect is characterized by two phases. At the first stage, the piston effect and the processes of changing physical fields are non-stationary whereas at the second stage, the processes become stable. The speed of the circulation flow created by the piston effect, in accordance with the fill factor of a tunnel, is characterised by a linear relationship; the degree of its growth is directly proportional to the speed of a train. Based on the results from the present paper it is possible to calculate the velocity and consumption of an air flow in an underground space. The maximum value of air flow carried out by the piston effect does not exceed 90-100 m 3 /s. It corresponds to the stationary phase of motion, when the tunnel filling factor α = 0.35 and train speed is in the range of 40-45 km/h. Based on the obtained numerical simulation results, technological parameters for metro ventilation systems can be calculated more accurately.

The objective of this paper is to investigate the use of the 1-D wavelet analysis to extract several patterns from signals data sets collected from healthy and faulty input-output signals of control systems as a preliminary step in real-time implementation of fault detection diagnosis and isolation strategies. The 1-D wavelet analysis proved that is a useful tool for signals processing, design and analysis based on wavelet transforms found in a wide