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Background: Coronary thrombosis is the key pathogenic mechanism of acute heart attack, including non-ST segment elevation (NSTEMI). Given that, the detection of reliable markers of hemostasis disorders is important in the process of optimizing the diagnosis of NSTEMI. Material and methods: The study was conducted on 54 patients with NSTEMI (average age 69.7±1.5 years). In 60% of cases, 3-vessel disease was noted; 56% of patients had ejection fraction >50%, and Killip class I of heart failure was revealed in 78% of patients. With the help of the STA-Liatest (France) equipment, the blood tests determined the following hemostasis markers: fibrin monomers (FM), thrombotic complex activity of factors II, VII and X. Additional markers like Procoag, the coagulation indicator dependent on circulating phospholipids or SPA, D-dimers, as well as factors C, S and antithrombin III were appreciated. The values of these markers determined by the same method in 20 healthy persons (control group) were used as normal values. Results: Circulating level of FM on admission was increased twice, while the values of Procoag and SPA were significantly decreased by 35.3% compared to the control. Factors C, S and antithrombin III were 54-80% of the control value range, and D-dimers were within the permissible values. In the acute phase of the heart attack, a deterioration of hemostasis indicators was noted, excepting the D-dimers. The levels of FM determined 24 and 72 hours after revascularization were consistently increased (up to 3.8 times) compared to the control, while Procoag and SPA decreased by 54-57%. Further reduction of factors C, S and antithrombin III accounted for 42-54% of normal indicators. After 5 days, an improvement in hemostasis markers was observed, but a significant difference still remained comparing to the control group. Conclusions: The hemostasis particularities discovered in patients with NSTEMI indicate the features of an activated prothrombotic status, and FM could be an important diagnostic marker of NSTEMI, due to its most significant deviation from the normal value (>100%). It can reliably reflect the thrombin level, which triggers the last enzymatic phase of thrombus formation.

Water injection in internal combustion engines is mainly used for additional cooling of the combustion chamber and knock suppression. The main advantages of the water injection are the potential for the enhancement of the performance of the engine. Studies conducted so far have aimed to track engine performance at maximum load and fuel consumption (brake-specific fuel consumption BSFC). Specialized literature is less consistent as regards to the injection of water at medium and low loads. This work monitors the effects of water injection at medium loads and the evolution processes of the four-strokes in the engine with and without water injection. A side-valve, air cooled natural aspirated engine with water and fuel injections in the intake manifold was used for this study. The work during expansion was increased, but this trend was reversed by the higher loads required during intake, compression and exhaust strokes, leading to a reduction in the indicated efficiency when water was injected.

The solubility of triclocarban in ultrapure water and in several natural aqueous solutions is influenced by several environmental factors. In this study the variation of temperature, pH, ionic strength and concentration of the organic matter over the solubility of triclocarban was analysed. The results show that the solubility of triclocarban increases by increasing the contact time, longer than the time of equilibrium and the temperature. It is less influenced by the variations of pH and strongly influenced by the variation of ionic strength and by the natural organic matter into the studied aqueous matrices.

The influence of the chemical composition of natural waters on triclocarban (TCC) sorption on pristine and irradiated multi-walled carbon nanotubes (MWCNTs) at different temperatures was studied. Natural waters have been characterized in terms of the concentrations of cations and anions, pH, and electric conductivity. The sorption process of TCC on MWCNTs is influenced by both the chemical composition of natural waters and the variation of the temperature. The adsorption capacity of TCC on pristine and irradiated MWCNTs in the studied natural waters increased by increasing the temperature. The increase of the concentration of monovalent cations (Na+ and K+) in natural waters determined a significant decrease of the adsorption capacity of TCC on both pristine and irradiated MWCNTs while the increase of the bivalent cations (Ca2+ and Mg2+) determined an easy increase adsorption capacity. Freundlich and Langmuir models were selected to describe the steady adsorption of the TCC on the pristine and irradiated MWCNTs.

Waste heat recovery from exhaust gas is one of the most convenient methods to save energy in internal combustion engine-driven vehicles. This paper aims to investigate a reduction in waste heat from the exhaust gas of an internal combustion engine of a serial Diesel–electric hybrid bus by recovering part of the heat and converting it into useful power with the help of a split-flow supercritical CO2 (sCO2) recompression Brayton cycle. It can recover 17.01 kW of the total 33.47 kW of waste heat contained in exhaust gas from a 151 kW internal combustion engine. The thermal efficiency of the cycle is 38.51%, and the net power of the cycle is 6.55 kW. The variation in the sCO2 temperature at the shutdown of the internal combustion engine is analyzed, and a slow drop followed by a sudden and then a slow drop is observed. After 80 s from stopping the engine, the temperature drops by (23–33)% depending on the tube thickness of the recovery heat exchanger. The performances (net power, thermal efficiency, and waste heat recovery efficiency) of the split-flow sCO2 recompression Brayton cycle are clearly superior to those of the steam Rankine cycle and the organic Rankine cycle (ORC) with cyclopentane as a working fluid. [ABSTRACT FROM AUTHOR]

Nanocomposite materials have seen increased adoption in a wide range of applications, with toxic gas detection, such as carbon monoxide (CO), being of particular interest for this review. Such sensors are usually characterized by the presence of CO absorption sites in their structures, with the Langmuir reaction model offering a good description of the reaction mechanism involved in capturing the gas. Among the reviewed sensors, those that combined polymers with carbonaceous materials showed improvements in their analytical parameters such as increased sensitivities, wider dynamic ranges, and faster response times. Moreover, it was observed that the CO reaction mechanism can differ when measured in mixtures with other gases as opposed to when it is detected in isolation, which leads to lower sensitivities to the target gas. To better understand such changes, we offer a complete description of carbon nanostructure-based chemosensors for the detection of CO from the sensing mechanism of each material to the water solution strategies for the composite nanomaterials and the choice of morphology for enhancing a layers’ conductivity. Then, a series of state-of-the-art resistive chemosensors that make use of nanocomposite materials is analyzed, with performance being assessed based on their detection range and sensitivity.

The paper analyses the behaviour of cereal straw briquettes in combustion at energy installations equipped with fixed grates for powers below 75 kW, intended for uses in the field of agriculture. A comparison was made with the combustion of sawdust briquettes. A wider involvement of the energy use of cereal straws, which are in large quantities in certain agricultural regimes, is envisaged. The research includes a new production of cereal straw briquettes from the Oltenia area, previous research being carried out with briquettes made in the agricultural area of North-Eastern Moldova. The use of cereal straw for energy purposes, however, collided with the final processes of combustion when the ash becomes adherent to the elements of the combustion plant, so this new approach will contribute to broadening the knowledge about this biofuel that represents a certain future. The work presented experimental combustion tests comparing the two fuels (cereal straw briquettes and wood sawdust respectively) at a 55 kW pilot plant, plant equipped with a fixed grill. [ABSTRACT FROM AUTHOR]

In this manuscript an improved sorbent based on modified exfoliated carbon nanoplatelets, applied in the removal of ammonium from aqueous samples, is presented. This sorbent showed better efficiency in comparison with the previous one obtained in our group for ammonium removal, the values of the maximum sorption capacity being improved from 10 to 12.04 mg/g. In terms of kinetics and sorption characteristic parameters, their values were also improved. Based on these results, a sorption mechanism was proposed, taking into account ion-exchange and chemisorption processes at the surface of the oxidized exfoliated carbon nanoplatelets. Future applications for simultaneous removal of other positive charged contaminants from natural waters might be possible.

In this work, we perform Bayesian inference tasks for the chemical master equation in the tensor-train format. The tensor-train approximation has been proven to be very efficient in representing high-dimensional data arising from the explicit representation of the chemical master equation solution. An additional advantage of representing the probability mass function in the tensor-train format is that parametric dependency can be easily incorporated by introducing a tensor product basis expansion in the parameter space. Time is treated as an additional dimension of the tensor and a linear system is derived to solve the chemical master equation in time. We exemplify the tensor-train method by performing inference tasks such as smoothing and parameter inference using the tensor-train framework. A very high compression ratio is observed for storing the probability mass function of the solution. Since all linear algebra operations are performed in the tensor-train format, a significant reduction in the computational time is observed as well. [ABSTRACT FROM AUTHOR]

In this work, fullerene (C60) was selected as a model carbon nanomaterial, humic acid (HA) as the model natural organic matter and bisphenol A (BPA), as a moderate hydrophobic organic contaminant. The effects of ionic strength, concentration of organic matter and of the pH over the adsorption of BPA on C60 were studied, as well as the competition between the BPA and the HA at the active sites of the C60. A possible adsorption mechanism was proposed as well as an attempt to study the sorption process in real environmental samples with characteristics alike to the optimum ones found in the synthetic samples studied.

Energy and economic performance of an organic Rankine cycle (ORC) system designed to recycle waste heat of a steam boiler was analysed. Optimisation of ORC system was performed by using the Cycle-Tempo software and the REFPROP program. The selected working fluid was R245fa. For the exhaust gases temperature of 163°C and mass flow rate of 11.83 kg/s, cooling water temperature of 20°C resulted a gross efficiency of 21.02% and a cost of 2987 €/kW, an electricity levelised cost of 102 €/kWh and a payback period of 5.5 years.

The aim of this paper is to provide a comprehensive overview of how electricity is produced from different sources and the electricity needs of the consumer. According to the Green Deal pact, the objective is to gradually reduce polluting emissions in the energy sector by 2050. In the meantime, the CO2 intensive thermal power plants (those using coal and heavy oil) will be closed and strategic investments in green energy sources will be pursued. This paper presents a detailed analysis of the profile of the Romanian electricity producer over a period of one year. Furthermore, this paper explores the possibility for the energy producer to adapt to consumer demand to reduce electricity imports, strategic locations for the installation of farms using renewable energy, and the current capacity of the national distribution system. This paper analyses electricity only quantitatively and not qualitatively, as well as the way the supplier follows consumers' need. The paper concludes on possible problems that may arise from the case of green energy. [ABSTRACT FROM AUTHOR]

The need for reducing fossil fuel consumption and greenhouse gas (GHG) emissions in internal combustion engines has raised the opportunity for the use of renewable energy sources. For the progressive replacement of fossil fuels like diesel, those derived from the sustainable management of forest resources may be a good option. In Portugal, pine trees (pinus pinaster) are among the most widely cultivated tree species. Turpentine can be extracted from their sap without harming the tree. Turpentine is known to be a good fuel with a lower viscosity than regular diesel but with a comparable caloric value, boiling point and ignition characteristics, although it is not widely used as a compression ignition fuel. Moreover, recent research has highlighted the possibility of substantially increasing the turpentine yield through biotechnology, bringing it closer to economic viability. The present study investigates the performance, pollutant emissions and fuel consumption of a 1.6 L four-cylinder direct-injection diesel engine operating with several blends of commercial diesel fuel and turpentine obtained from pine trees. The aim of this study was to assess whether it would be possible to maintain or even improve the performance, fuel consumption and GHG and pollutant emissions (HC, NOx, CO and PM) of the engine with the partial incorporation of this biofuel. Turpentine blends of up to 30% in substitution of regular diesel fuel were tested. The main novelties of the present work are related to (i) the careful testing of a still-insufficiently studied fuel that could gain economical attractiveness with the recent developments in yield improvement through biotechnology and (ii) the tests conducted under fixed engine load positions typical of road and highway conditions. The addition of this biofuel only slightly impacted the engine performance parameters. However, a slightly positive effect was observed in terms of torque, with an increase of up to 7.9% at low load for the 15T85D mixture and 6.8% at high load being observed. Power registered an increase of 9% for the 15T85D mixture at low speed and an increase of 5% for the 30T70D mixture at high speed when compared to the reference fuel (commercial diesel fuel). While the efficiency and fossil GHG emissions were improved with the incorporation of turpentine, it had a mixed effect on polluting emissions such as unburned hydrocarbons (HC) and smoke (PM) and a negative effect on nitrogen oxides (NOx). NOx emissions increased by 30% for high loads and 20% for low loads, mainly as an indirect effect of the improvement in the engine performance and not so much as a consequence of the marginally higher oxygen content of turpentine relative to commercial diesel fuel. [ABSTRACT FROM AUTHOR]

The low-enthalpy geothermal sources can be efficiently exploited for heat and power cogeneration by using the KCS-34 Kalina cycle systems. The maximum power for given heat source temperature and cooling temperature is obtained for a certain value of the ammonia-water solution concentration and turbine exit pressure. The Cycle-Tempo simulation software is a very useful tool to investigate variation of some cycle parameters in order to obtain the maximum energy efficiency. In this paper the performance of a KCS-34 Kalina cycle based CHP plant is investigated to exploit a geothermal source with 120°C temperature present in North-West of Romania. It was found that by using the heat and power cogeneration the energy efficiency can be increased from 16.76% to 57.86% in winter and to 33.44% in summer.

The municipal solid wastes (MSW) can be turned into resources through recycling and energy recovery. To obtain the maximum amount of energy, the appropriate technology must be applied to waste treatment. The composition and characteristics of municipal solid wastes are determinant for technologies choice for MSW in a city/region. Municipal authorities from the Galati city proposed a recovery rate of recyclable materials of 60% from MSW and treatment of the post-recycling MSW as follow: biodegradable fraction by anaerobic digestion and the combustible fraction by incineration or gasification. In this study traditional and innovative waste to energy technologies have been analysed and the potential of electrical energy of waste has been estimated. Results show that plasma gasification system of raw MSW coupled with gas turbine engine has almost the same electrical energy production (32.92 GWh/year) as conventional gasification of combustible material from MSW (17.21GWh/year) coupled with anaerobic digestion of organic fraction of MSW (11.65 GWh/year). By recovering and using the landfill gas from the Tirighina landfill, 6.68 GWh of electricity can be produced annually.

A thermodynamics study on exfoliated graphite nanoplatelets dispersed in tetrahydrofuran in comparison with activated carbon dispersed in same solvent was realised. The refractive index, speed of sound, and density of diluted mixed binary solutions of exfoliated graphite nanoplatelets and activated carbon in tetrahydrofuran were measured between 0 and 100 kg·m−3 with composition step of 20 kg·m−3 and at temperatures from 293.15 to 308.15 K and at normal pressure. The isentropic compressibility, acoustic impedance, specific refraction, relaxation strength, and space-filling factor have been evaluated for six concentrations, at four different temperatures for each system. The identified possible molecular interactions between the edges and the surface of exfoliated graphite nanoplatelets and tetrahydrofuran molecules, which include modifications in the structure of exfoliated nanostructured materials in tetrahydrofuran solvent and the influence of the temperature, and of the solute concentration have been calculated based on the obtained experimental values.

This article states the problems with the use of central heating stations, as well as the need to introduce individual heat points. As a result, the authors considered the issue of improving the energy efficiency of heat supply systems in Russian cities while replacing central heating stations with individual heat points. The beneficial effects of the activities are especially noted.

In this work, Sb (III) adsorption on oxidized exfoliated graphite nanoplatelets (ox-xGnP) was evaluated for the first time, to the best of our knowledge. The ox-xGnP were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), Brunauer⁻Emmet⁻Teller (BET) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM) equipped with energy-dispersive X-ray spectroscopy (EDX), and Zeta potential analysis. The adsorption parameters, such as pH and contact time, were optimized, and the best adsorption capacity obtained was 8.91 mg g−1 at pH = 7.0, 1.0 mg ox-xGnP/100 mL solution, T = 293 K, 1.0 mg L−1, Sb (III), 25 min contact time. The best correlation of the kinetic data was described by a pseudo-first-order kinetic model, with R2 = 0.999. The adsorption isotherms of Sb (III) onto ox-xGnP were best described by the Langmuir isotherm model. The thermodynamic parameters showed that the adsorption process was exothermic and spontaneous.

The influence of the chemical composition of natural waters on triclocarban (TCC) sorption on pristine and irradiated multi-walled carbon nanotubes (MWCNTs) at different temperatures was studied. Natural waters have been characterized in terms of the concentrations of cations and anions, pH, and electric conductivity. The sorption process of TCC on MWCNTs is influenced by both the chemical composition of natural waters and the variation of the temperature. The adsorption capacity of TCC on pristine and irradiated MWCNTs in the studied natural waters increased by increasing the temperature. The increase of the concentration of monovalent cations (Na+ and K+) in natural waters determined a significant decrease of the adsorption capacity of TCC on both pristine and irradiated MWCNTs while the increase of the bivalent cations (Ca2+ and Mg2+) determined an easy increase adsorption capacity. Freundlich and Langmuir models were selected to describe the steady adsorption of the TCC on the pristine and irradiated MWCNTs. [ABSTRACT FROM AUTHOR]

In spite of the tremendous advances in computing power and continuous improvements in simulation software made in recent decades, the accurate estimation of wind turbine performance using numerical methods remains challenging. Wind turbine aerodynamics, especially when operating outside of the design envelope, is highly complex: blade stall, laminar-to-turbulent boundary layer transition, rotational effects (lift augmentation near blade root), and tip losses are present. The scope of this research is to show that the classic Reynolds-Averaged Navier–Stokes (RANS) modeling approach, although extensively tried and tested, is not yet exhausted. The NREL Phase VI rotor was used as a basis for numerical methodology development, verification and validation. The numerical model results are compared in detail with the available measured data, both globally (turbine torque and thrust, and blade bending moment) and locally (pressure coefficient distributions and aerodynamic force coefficients at several locations on the blade) over the entire experimental wind speed range. Stall initiation and spread over the blade span are well captured by the model, and rotor performance is predicted with good accuracy. RANS still presents significant value for wind turbine engineering, with a great balance between accuracy and computational cost. The present work brings potential impact on all applications of wind turbines, especially targeting offshore wind energy extraction for which great development is expected in the near future. [ABSTRACT FROM AUTHOR]

One way to reduce the heat loss of the steam boiler is to reduce the blowdown rate and recover the heat from the purged water. Purging the boiler, although necessary, represents a loss of treated water and a loss of heat because the purged water is water brought to saturation. Blowdown recovery must be done according to the available users/consumers. The paper analyses the recovery of blowdown of a steam boiler of 420 t/h capacity by using a flash separator and a makeup water preheater. The flash steam is used for the feed water deaeration. The heat recovered from the blowdown can reach 97%, and the recovered water can reach 43%. [ABSTRACT FROM AUTHOR]

The solubility of triclocarban in ultrapure water and in several natural aqueous solutions is influenced by several environmental factors. In this study the variation of temperature, pH, ionic strength and concentration of the organic matter over the solubility of triclocarban was analysed. The results show that the solubility of triclocarban increases by increasing the contact time, longer than the time of equilibrium and the temperature. It is less influenced by the variations of pH and strongly influenced by the variation of ionic strength and by the natural organic matter into the studied aqueous matrices. [ABSTRACT FROM AUTHOR]

This article develops a data-driven magnetostatic finite-element (FE) solver that directly exploits the measured material data instead of a material curve constructed from it. The distances between the field solution and the measurement points are minimized while enforcing Maxwell’s equations. The minimization problem is solved by employing the Lagrange multiplier approach. The procedure wraps the FE method within an outer data-driven iteration. The method is capable of considering anisotropic materials and is adapted to deal with models featuring a combination of exact material knowledge and measured material data. Thereto, three approaches with an increasing level of intrusivity according to the FE formulation are proposed. The numerical results for a quadrupole-magnet model show that data-driven field simulation is feasible and affordable and overcomes the need of modeling the material law. [ABSTRACT FROM AUTHOR]

The energy, economic and environmental analysis of a solar heating system with seasonal heat storage integrated into a district heating system based on natural gas boiler was performed. The solar collector field has a surface area of 8720 m2 and the pit seasonal heat storage has a volume of 10000 m3. This system covers 79% of the total yearly heat demand of the 15 multifamily buildings with 1500 inhabitants. The total system investment cost (2974100 €) may be recovered in about 17 years. The environmental impact of solar heating system integration is the decrease of CO2 emission by 79%. [ABSTRACT FROM AUTHOR]

The sorption of triclocarban (TCC), in simulated environmental media on fullerene C60 was studied, by using humic acid as model natural organic matter and fullerene C60 non-irradiated and irradiated (weathered by mimicking environmental conditions). The effects of ionic strength, concentration of organic matter and of the pH over the adsorption of TCC on C60 were studied and a model for the adsorption mechanism was developed. [ABSTRACT FROM AUTHOR]