EI Compendex Plus

This study investigates the removal of malachite green (MG) dye by adsorption process using as adsorbent a waste byproduct from lightweight composite brick production, composed of clay and 5 wt.% argan nut shell and designed as waste bricks (WB). Characterization of the adsorbent (WB) was conducted using several techniques such as XRD, XRF, FTIR, etc. Optimal conditions for the adsorption process of MG dye with WB were carried out, considering adsorbent dose (0.02–0.4 g/mL), pH (2–12), contact time (0–360 min), and MG dye concentration (20–210 mg/L). The obtained outcomes indicated that the optimal parameters for a dye concentration of 20 mg/L are an adsorbent dose of 0.15 g/mL, a pH of 10, and an adsorption time of 180 minutes. Furthermore, kinetic, isotherm, and thermodynamic adsorption have been evaluated. The results highlighted that the pseudo second-order and Langmuir model described accurately the adsorption process with an adsorption capacity of about 2.66 mg/g and 23.48 mg/g respectively. While the thermodynamic study conducted at four temperatures (298 K, 308 K, 318 K, 328 K) revealed that the adsorption process is spontaneous and endothermic in nature. Finally, a phytotoxicity test of malachite green dye solutions was carried out using wheat and lentil seeds confirming the treatment effectiveness of the adsorbent.

The paper describes a new approach to the assessment of symmetry in HBIM datasets on the example of the Tower of Gediminas in Vilnius (Lithuania). Symmetry is a principal component of the design and construction of ancient, medieval, Renaissance, and other epochs. The unified methodology involves the processing of LiDAR point clouds and applies to objects with a regular polygon cross-section. Proposed HBIM parameters introduce a uniform description of features of symmetry of historical buildings, which provides new insights into the original design of spatial relationships between the buildings’ architectural elements useful for professional conservators and renovators. The validation of the new approach involved well-established TLS and, taking into account the current development of drone technologies, ALS measurements. The obtained converging and similar estimates showed the applicability of both LiDAR technologies. Hence, the study proposes the introduction of the new symmetry parameters into the HBIM products and software.

In this study, the models for the DNA origami lattice will be investigated. Our aim is to theoretically explore the ways of constructing DNA origami. To achieve this goal the DNA origami structure, consisting of nanowires embedded in a host material, will be treated from the perspective of nanowire metamaterial. Surface plasmon polaritons propagating at the interface of air and DNA metamaterial are analyzed. The dispersion relation is attained using the transfer matrix technique and employing continuity conditions of electric fields and their derivatives at the boundary separating two regions. We have concluded that with numerous nanowires into the metamaterial unit, cell frequencies of surface plasmon polaritons are altered to higher frequencies. In this study, we have studied the effect of modifications of the metamaterial, allowing for the shift of the dispersion maps toward higher frequencies. It is possible to obtain the propagation of spoof plasmons mimicking the behavior of surface waves at lower frequencies. All the properties and parameters of the inorganic metamaterials are applicable to study the phenomenon of the organic substances.

The paper presents an experimental analysis of the full-scale phase change material (PCM) thermal energy storage (TES) prototype that is designed for use in domestic hot water preparation systems. The PCM-TES prototype is based on the external arrangement of organic PCM and a custom-made compact fin-and-tube type of heat exchanger. The prototype has been designed, constructed, and tested according to the Ecodesign Directive requirements for water heaters and hot water storage tanks. Several parameters have been analysed, including the heat transfer fluid (HTF) temperature and mass flow rate, heat transfer rate, accumulated and released energy, and quantity of domestic hot water (DHW) delivered. Additional attention was paid to the reliability and repeatability of the results. Experimental research allowed to determine the quantity and temperature of DHW at a constant mass flow rate of 0.1 kg/s. The prototype unit showed that it can deliver 99.1 l of hot water at 40 °C for up to 15 min and 39 s, while the use of lower temperature DHW (up to 37 °C) allows to increase the quantity of hot water delivered up to 156.2 l. Experimental results showed the viability of the prototype, areas for improvement and further possibilities for its optimization. Overall, the study results are relevant for developing latent heat thermal energy storage systems using fin-and-tube heat exchangers in tanks and the feasibility of integrating such systems into DHW systems.

Investigations of the influence of dolomite powder (formed in the production of dolomite crushed stone) on the properties of fired clay products are presented. To obtain samples, dolomite powder was introduced in amounts 10 – 30% into the molding bodies, the firing temperature of the products was equal to 1000°C, and the isothermal soaking time 1 h. The investigations showed that with the addition of 10 – 30% dolomite powder the density of the fired brick is equal to 1.75 g/cm3, the compressive strength 14 – 28 MPa, water absorption 15.3 – 19.7%, total porosity 31 – 40.4%, and durability (frost resistance) at least 25 cycles.

In recent years, fiber-reinforced polymeric (FRP) materials have become promising alternatives to steel because of their lightweight, electromagnetic transparency, and corrosion resistance. However, the unfavorable environment (elevated temperature and high humidity in particular) can affect the long-term mechanical performance of these materials. Therefore, this study utilizes the previously developed testing layout and analytical model to simulate and quantify these unfavorable effects in concrete beams reinforced with FRP composites. The explicit analytical model quantifies the flexural stiffness reduction expressed in the equivalent stresses acting on the tensile concrete. This approach does not require specifying the loading history that makes it feasible for the comparative analysis of the stiffness degradation of FRP-reinforced concrete via a series of repeated mechanical tests corresponding to continuous exposition to the harsh environment. This study considers the open atmosphere corresponding to the Nord Europe climatic region. In addition, after applying the service load, the reference specimens were kept under laboratory conditions. The latter samples provide the reference for quantifying the stiffness degradation and the repeated mechanical load effect expressed in the residual deflection of the test sample. Thus, this study reveals that the open environment specifically affected the stiffness decay in the external bonded reinforcement system. In contrast, this effect in the near-surface mounted reinforcement system was insignificant.

The La0.66Sr0.34MnO3 (LSMO) films with thickness 200–330 nm have been grown at 750 °C on lattice-mismatched (001)-plane oriented yttria-stabilized zirconia (YSZ) using radio frequency magnetron sputtering technique. The films demonstrated columnar growth structure characterized by coexistance of grains with the averaged diameter of about 50 nm and well defined crystallographic orientations of a pseudocubic LSMO lattice, namely, (001)LSMO[110]//(001)YSZ[100] and (110)LSMO[110;100]//(100)YSZ[100]. Alternating current (AC) magnetic susceptibility, χ(H) ∼ dM/dH, and magnetoresistance, MR(H), of the films were measured at 78 and 295 K with DC magnetic field (H) applied either in-plane or out-of-plane. Unusually sharp peaks at H = ±HSW and clearly defined switching behaviour have been indicated at 78 K in both the χ(H) and MR(H) plots. The HSW values were found to increase with the out-of-plane angle, α, according to the relationship HSW = HSW0/cosα (HSW0 = 4.0 and 1.4 kA/m at 78 and 295 K, respectively) while negligible variation of HSW has been indicated by varying direction of H in a film plane. The investigations revealed close correlation between χ(H) and low-field magnetoresistance. The observed angle-dependent peak-like χ(H) anomalies have been explained assuming magnetization reversal of the multigrain films governed by interparticle interaction and pinning of magnetic domains at grain boundaries. Unusual pit-like anomaly of the transverse biased susceptibility (TS) indicated at H = ±HSW has been explained in a framework of the TS theory developed for isolated uniaxal ferromagnetic particles assuming coexistance of grains with several fixed easy axis orientations in a film plane.

Nowadays, fibre reinforced polymer (FRP) reinforcements are considered as appropriate strengthening solution for reinforced concrete (RC) structures worldwide. FRP materials gained its popularity due to reduced labour cost, corrosion resistance, good compliance to aesthetical and design requirements. Generally, strengthening is required for structures with deflections and crack widths exceeding design limits, therefore FRP reinforcement needs pre-stressing. Unfortunately, there is a lack of such research and the behaviour of such structures is described on the basis of research data where RC elements worked with FRP reinforcement altogether from the start of loading. The behaviour of the structure will be different in practice. For the above reasons, a crack computation model was proposed, which allows to predict the development of the crack taking into account the influence of external load action and pre-tension of the FRP reinforcement. The proposed calculation model was validated by experimental data of the beams strengthened with different FRP reinforcements, taking into account effects of FRP pre-stressing and initial stress-strain state of concrete elements.

The depletion of fossil feedstock, climate change, and environmental pollution push the scientific and industrial communities to focus their researches and production on more ecological materials using sustainable approaches. The substitution of fossil feedstock by renewable substances from biomass is driven by the development of new materials having different molecular architectures with greater or new performance characteristics. Innovative development based on ideas of circular economy and cleaner production requires new solutions in the production of bio-based components for the polymers industry, which could generate more benefits for the economics and environment. Natural oils are sustainable, eco-friendly renewable resources that can be applied to synthesize a new class of precursors such as polyols that can be implemented in the production of different polymeric materials, such as polyurethanes. Polyurethanes are commonly derived by the reaction of low molecular weight polyols with isocyanates. Both of the raw materials used contain at least two or more functional groups per molecule, which result in the formation of branched, linear or cross-linked polyurethane products. Nowadays, bio-based polyurethane foams from various vegetable- or waste-based oils and natural fillers as reinforcement are of great importance in order to increase the renewable content of the resultant products. Therefore, the chapter reveals the advantages of natural oil-based and natural filler reinforced polyurethane foams with improved performance characteristics and application possibilities in the building industry.

The article examines tools, which may be used to assess service quality in aviation and to analyze service quality models. Many experts analyzing customer service state that a good customer service is one of the most important reasons for customer satisfaction and loyalty. This is particularly important in aviation customer service, because aviation services are subject to higher requirements due to the specifics of the service. In pursuit of the top-level customer service, refining customer needs and expectations becomes very important, because knowing customer expectations allows purposefully focusing the customer service process based on them and achieving high customer satisfaction. Also, the nature of customer service in aviation is different; here staff must be trained with more scrutiny and examples of specific situations.In order to investigate the quality of customer service, conducting a theoretical analysis of customer needs or service criteria alone is not sufficient. Customer service quality is perceived differently due to a variety of factors, thus service quality models are used to find out customer expectations or to identify service gaps, also helping to conduct analyses and to improve processes. The analysis of customer service models revealed that they have not been adapted for aviation due to the following: their focus on a single service factor, the lack of relationship between components, neglected role of employees in customer service, and the like.