Multiplexing digital information using hyperchaotic optoelectronic oscillators with nonlinear time-delayed feedback loops

<div class="section abstract"><div class="htmlview paragraph">The tests related to the exhaust emissions from non-road vehicles are currently performed on a chassis dynamometer under the name of NRSC (ISO 8178) and NRTC. In light of the growing requirements related to the environment protection in transport the authors recommend determining the exhaust emissions through real vehicle operating conditions. The tests carried out under real operating conditions could be used for the process of optimization of future power trains of regular road vehicles and non-road vehicles. What is more, these tests should be taken into account in the works on the changes of the legislation related to the emission limits from combustion engines. The paper presents the results of the tests on the exhaust emissions from an agricultural harvester engine and a tractor engine in real operating conditions. The harvester operation during the test consisted in crops collection from the field and the tractor operation during the test consisted in plowing. The authors used SEMTECH DS, a portable exhaust emissions analyzer by SENSORS. Based on the obtained results an analysis of the exhaust emissions was performed in the aspect of selected engine operating parameters. The paper also presents an analysis determining the most frequently used range of engine loads and engine speeds. The obtained time density characteristics (distribution of engine speeds and loads in time) of the engines were juxtaposed to the engine measuring points of the exhaust emissions homologation test. The final part of the paper discusses the prospects and trends in further works on the exhaust emissions measurement under real operating conditions from vehicle and machinery used in agriculture as well as other vehicles of non-road application.</div></div>

A low cost, high rate, single communication channel at the SOLIS

Series Resistance Measurement of Solar PV Modules Using Mesh in Real Outdoor Condition

Polarization Mode Dispersion (PMD) plays a great role in high bit rate optical communication systems. This factor had been studied thoroughly in this article of optical layout simulation by (OptiSystem7.0). This simulation had revealed some interesting features of (PMD) relating its major parameters, i.e, (PMD coefficient(DPMD)), mean scattering section, and scattering section dispersion). An optimum values have found for the mentioned parameters were: DPMD= 2, mean scattering section=150, scattering section dispersion=110. The opportunity to study the influence of PMD on high bit rate network can be of a substantial benefits to engineer the optical communication network.

The main part of heating systems and domestic hot water systems are based on the natural gas boilers. Forincreasing the overall performance of such heating system the condensation gas boilers was developed and are used. Howevereven such type of boilers don't use all energy which is released from a fuel combustion. The main factors influencing thelowering of overall performance of condensation gas boilers in case of operation in real conditions are considered. Thestructure of the developed mathematical model allowing estimating the overall performance of condensation gas boilers(CGB) in the conditions of real operation is considered. Performace evaluation computer experiments of such CGB during aheating season for real weather conditions of two regions of Ukraine was made. Graphic dependences of temperatureconditions and heating system effectiveness change throughout a heating season are given. It was proved that normal CGBdoes not completely use all calorific value of fuel, thus, it isn't effective. It was also proved that the efficiency of such boilerssignificantly changes during a heating season depending on weather conditions and doesn't reach the greatest possible value.The possibility of increasing the efficiency of CGB due to hydraulic division of heating and condensation sections and use ofthe vapor-compression heat pump for deeper cooling of combustion gases and removing of the highest possible amount ofthermal energy from them are considered. The scheme of heat pump connection to the heating system with a convenient gasboiler and the separate condensation economizer allowing to cool combustion gases deeply below a dew point and to warm upthe return heat carrier before a boiler input is provided. The technological diagram of the year-round use of the heat pump forhot water heating after the end of heating season, without gas use is offered.

Influence of CeO2 nanoparticles in the stability of electrodeposited Ni anodes for alkaline electrolysers

We propose an efficient and fast bit-multiplexed encryption scheme exploiting hyperchaotic regimes of a single nonlinear oscillator with multiple time-delay feedback loops. Each data stream is encrypted by digitally modulating the values of the various time delays and decrypted using chaos synchronization and cross-correlation measurements. We have numerically applied our approach to an optoelectronic chaotic oscillator based on standard semiconductor lasers subjected to multiple feedbacks and have demonstrated successful data transmission and recovery between multiple users at several Gbits/s on a single communication channel.

The main object of this paper is to present the design and the results of an experimental test campaign on an innovative device for the exploitation of marine and river currents. All the work has been carried out at the Department of Aerospace Engineering of the University of Naples “Federico II” and the test campaign has been first performed in the naval towing tank belonging to Naval Department of same University and then in real condition in Messina Strait between Sicily island and mainland. This location is the only one in Italy suitable as test site with tidal current reaching a maximum speed of 3 m/s. The turbine's blade was first carefully designed with particular care for the cavitation problems. Two different series of experimental test in naval tanks aimed to optimize the general layout of the device and the tests performed in Messina Strait mainly aimed to confirm the feasibility of the system and to evaluate its response in real operating conditions. The tests have confirmed the good dynamic behavior of the whole system and its feasibility to be scaled up to real scale.

The paper presents the proposed proprietary M exhaust emission indicator, which is based on the assumption that CO2 emissions are a measure of the correctness of the combustion process. The measurements were performed using a farm tractor meeting the Tier 3 emission norm, operated in real conditions during plowing work. The tests were carried out for a given land section at three speeds In the analysis of test results, the net engine work was used, as it is carried out in the type approval procedures. When measuring in real operating conditions, the torque read from the OBD system is overstated because it takes into account the engine’s internal resistance. In the analysis of test results, the fuel consumption, emission indicators of gaseous compounds and particulates were determined, and the best conditions for conducting agricultural works were indicated in terms of their impact on the natural environment. The aim of the work is to verify the possibility of determining the emission index for an off-road vehicle and a comparative analysis of its values for various operating parameters of a farm tractor. On this basis, it was found that the lowest values of the M identity were recorded for the test characterized by a vehicle speed of 15 km/h.

For the design and optimization of wind turbine blades knowledge about the state of the boundary layers at the rotor is important since the energy yield strongly depends on this issue. Blades with an extended laminar boundary layer zone offer a higher energy yield. Owing to the complexity of the experimental setup, up to now most research on transition was conducted in wind tunnels and field measurements are rare. In the present study the aerodynamic boundary layer at a rotor blade is investigated while the turbine is working under real operating conditions in the atmosphere. Hence important effects such as the rotation of the rotor and the unsteady behavior of the inflow are taken into account. The blade is equipped with a hot film and pressure tubes in order to detect disturbances in the boundary layer and to gain information about the flow field. A preliminary analysis of the time signal and the calculated energy spectra of the hot film measurements leads to two results. First, it is possible to determine the state of the boundary layer (laminar or turbulent). Second, we assume that in case of a medium rotational speed transition following the Tollmien-Schlichting scenario occurs. This assumption has to be verified by comparison with further measurements.

Waste lube-oil based fuel characterization in real conditions. Case study: Bottom-trawl fishing vessel powered with medium speed diesel engine

Long-term Performance Analysis of CdTe PV module in real operating conditions

Urban runoff frequently carries elevated concentrations of heavy metals such as nickel (Ni), posing significant environmental and public-health risks. Sustainable Urban Drainage Systems (SUDS) offer a promising pathway to mitigate these impacts, particularly through the use of filter media that enhance water decontamination. This study evaluates Filtralite, a lightweight expanded clay aggregate, as a filtration medium for Ni removal, with special emphasis on the evolution of pH under prolonged operational conditions and on the influence of particle size on the material’s treatment capacity.The research was based on an 80-day experiment designed to simulate an accelerated weathering process similar to what occurs under real operating conditions when SUDS interact with rainfall. Four granulometric fractions (2 mm, 1 mm, 0.5 mm, and 0.25 mm) were tested under controlled, repeated washing cycles carried out statically: the Filtralite was kept submerged in beakers, and its water was replaced on an approximately daily basis throughout the 80-day period. The pH values of the effluent were systematically recorded and interpreted as a proxy for the material’s alkalinity-generating capacity—an essential driver of Ni removal from the contaminated solution.Results demonstrate a consistent granulometry-dependent pattern in pH evolution. Coarser fractions (2 and 1 mm) experienced a more rapid decline in alkalinity than finer ones: although initial effluent pH values exceeded 10, they dropped below the threshold required for efficient Ni precipitation (≈8.5–9) after only a few litres of cumulative washing. The 2 mm fraction dropped to pH 8–8.5 after approximately 8–10 L of equivalent runoff, suggesting a short effective lifespan in real SUDS applications. The 1 mm fraction exhibited a slower decline, maintaining pH > 9 for a longer period, but ultimately converging toward circumneutral values at extended washing volumes. In contrast, finer fractions (0.5 and 0.25 mm) preserved alkaline conditions throughout most of the experiment. The 0.5 mm material sustained pH values in the range 9–10 for the majority of the test, indicating a more stable and gradual release of alkaline species. The finest fraction (0.25 mm) provided the most robust performance: effluent pH consistently remained between 9.5 and 10 even under high cumulative washing volumes, reflecting the strong buffering capacity associated with its larger specific surface area.Overall, the findings confirm that Filtralite is an effective and sustainable medium for Ni removal in SUDS, although its long-term performance is highly sensitive to granulometry. Fine fractions provide a prolonged alkaline environment that enhances precipitation-driven removal. These results suggest that finer Filtralite may offer favourable characteristics for potential field applications, supporting more stable and efficient metal removal over extended periods. However, the reduced particle size also implies lower hydraulic conductivity compared to coarser fractions, which could limit infiltration performance in practical implementations. Validation under real operating conditions is therefore still required.

The compatibility of seal materials with the working fluid is crucial for the flawless, energy-saving, environmentally sustainable, and safe operation of any technical system. This is especially true for hydraulic systems operating under high operating pressure. The problem of materials compatibility comes into play when either a new type of seal material or a new type of fluid comes into use. The paper discusses the research findings regarding material compatibility testing of new high-tech ionic hydraulic fluids with commonly used seal materials. Due to the completely different chemical composition of these new fluids compared to the classical mineral-based oil, for these fluids, there are no standardized testing procedures. In these cases, we can only lean on the Standards that apply to classical fluids, which can lead to incorrect results. In the forefront of the paper is the discrepancy between the results obtained by the standardized test, and the test under real operating conditions. FKM, an excellent material for seals, proved to be the most suitable in the case of using ionic hydraulic fluid, according to a standardized test. However, it failed in the comparison test under real operating conditions, as the cylinder leaked. NBR seals proved to be a better solution.

The data from three solar thermal collector systems installed in dormitories of the University of Latvia in Riga are analysed in detail to obtain parameters that characterise the operation of such systems in real operation conditions in Riga, Latvia. All the systems were installed in 2019�2020 and the data for one full year is available for the study. The area and the power output for the observed solar thermal collectors are similar�63 m2 with 51 kW for each. The differences exist only in the orientation of the collectors depending on the building�s roof, tilt angle and the mounting combination (one or two rows). Each system is equipped with hot water accumulator tanks with a total volume of 3000 l to ensure hot water supply during peak demands (typically in the mornings). Analysis of the recorded data from the systems shows the actual energy produced with the help of solar thermal collector systems in real operation conditions. Calculations determine the actual energy production, which is estimated in the range of 320�380 kWh/m2 annually, or 395�470 kWh/kW per installed power output depending on the system�s spatial orientation. The most efficient is a south-east-oriented collector at a 25� tilt angle, reaching 50% efficiency (from available energy) during the summer days. The difference from the planned 500 kWh/m2 is explained due to higher cloudiness and the fact that the system is not even activated on cold days.