Polymer membranes with immobilized ligands are encouraging alternatives for the removal of toxic metal ions from aquatic waste streams, including industrial wastewater, in view of their high selectivity, stability, removal efficacy and low energy demands. In this study, polymer inclusion membranes (PIMs) based on cellulose triacetate, with a calix[4]pyrrole derivative as an ion carrier, were tested for their capability to dispose mercury (Hg(II)) ions from industrial wastewater. The impacts were assessed relative to carrier content, the quantity of plasticizer in the membrane, the hydrocholoric acid concentration in the source phase, and the character of the receiving phase on the performance of Hg(II) elimination. Optimally designed PIMs could be an interesting option for the industrial wastewater treatment due to the high removal efficiency of Hg(II) and great repeatability. To evaluate the performance of Hg(II) separation, we used the following parameters: the impact of the carrier concentration, the quantity of plasticizer in the membrane, the acidity of the source phase, the type of the strip phase and the feasibility of reusing the membrane.2) and sodium (NaCl) chlorides, hydrochloric acid (HCl) and potassium iodide (KI) provided by POCh  and organic chemicals, i.e., cellulose triacetate (CTA), o-nitrophenyl octyl ether (o-NPOE) and dichloromethane (DCM) obtained from Fluka , all of analytical grade, were used with no further cleansing. Double distillated water with a conductivity of 0.1 µS/cm was used to prepare aqueous solutions. Inorganic reagents, i.e., mercury   and by FT-IR spectrum obtained using Thermo Nicolet Nexus . The synthesis of ole (KP)  was desc1H NMR : 6.97 , 5.88 , 1.49 . 13C NMR : 29.10 (CH3), 35.19 (C(CH3)2), 102.83 (ArH), 138.43 (Ar).−1 responds to N-H stretching while a less intensive peak at 3105 cm−1 corresponds with =C-H stretching from an aromatic ring. The successive peaks at 2970, 2934 and 2870 cm−1 reflect C-H stretching bonds from methyl groups. Stretching bonds from pyrrole units and methyl groups indicate presence of meso-octamethylcalix[4]pyrrole. For pyrrole units, one strong and sharp peak at 3443 cm1H NMR, 13C NMR and FT-IR spectra are provided in The o-nitrophenyl octyl ether and meso-octamethylcalix[4]pyrrole as ion carrier. A glass ring with a diameter of 5.0 cm connected to a glass plate with a CTA glue-dichloromethane was filled with the predetermined volumes of CTA solution, plasticizer and carrier mixture and left overnight in room temperature to evaporate DCM. Wetting in cold water allowed for the detachment of the resultant membrane from the glass plate. The effective surface area of the CTA membrane was of 4.9 cm2, while its average thickness of 24 μm was determined (accuracy of 1.0 μm standard deviation over four readings) by an A2002M type digital ultrameter from Inco-Veritas.The PIMs were prepared according to the procedure previously described . The appZ values within the box cursor according to the following formula: iZ is the current z value, and N is the number of points within the box cursorsAtomic force microscopy (AFM)  was applied to determine the surface characteristics of polymer membranes, while the analysis of the pore characteristics was performed by the image processing program AFM NanoScope v.720 , which enabled the roughness (Ra) parameter to be calculated as the standard deviation of the The principle of operation of AFM consisted in measuring the magnitude of the static deflection of the lever during the sweep of the lever on the sample surface. The topography of the sample surface (change of the coordinate of the axis perpendicular to the sample surface) affects the angle of inclination of the lever and, thus, changes the intensity of illumination of the photodetector sectors. The compensation voltage changes are equivalent to the relative height of the roughness on the sample surface.Membrane samples were frozen in liquid nitrogen, which resulted in rapid fracturing and in a clean break of fracture image to observe the cross-section. The samples were fixed to metal stubs with conductive glue, with the fractured edge up, and then coated with gold by spraying, and they were examined by a 5 kV scanning electron microscope (SEM)  (Hitachi S4500) to analyze membrane morphology at the magnification of around 200 µm.3 of ultrapure water and shaken for 24 h. The mass losses were calculated as a difference between membranes weights before and after this procedure. The masses of membranes were also measured before and after mercury ions transport across PIMs.To investigate the stability of PIMs in terms of mass loss, which is related to leaching of the carrier and/or plasticizer, they were immersed in 100 cmThe measurement of the contact angle of membranes was carried out with the drop shape method using a Tracker tensiometer . Each membrane was placed on a level table, and then 3 µL of deionized water was dispensed onto the surface of the membrane. Afterward, the angle between the membrane surface and the tangent surface to the droplet at the point of contact with the membrane was examined with the help of a camera directed at the table. The contact angle was read after 300 s for the drop that was provided (the measurement was considered to be stabilized then).3) in hydrochloric acid media, whereas the role of aqueous receiving phase was performed by solutions of sodium chloride, potassium iodide or distilled water (50 cm3). Both source and receiving aqueous phases were synchronously stirred at 600 rpm, and aqueous phases were sampled periodically with the use of a sampling port with a syringe for analyzing Hg(II) concentrations. CX-731 Elmetron, a multifunctional pH-meter, was used to control the acidity of both aqueous phases, with a combined pH electrode, ERH-136, Hydromet, Poland. The experiment in terms of transport was performed at a room temperature (23–25 °C) in a two-compartment permeation cell described in our previous study , where tc is the metal ion concentration (mol/dm3) in the source phase at a given time, c0 is the initial Hg(II) concentration in the source phase (mol/dm3), k is the rate constant (s−1) and t is the transport time (s).The kinetics of the transport process through PIM was described by a first-order reaction with respect to metal ion concentrations :(2)ln versus time (2), whereas the permeability coefficient (P) was obtained from the following equation:V is the volume of aqueous source phase (m3), and A is the surface area of membrane (m2). The initial flux (J0) in (µmol/m2s) was determined as equal to the following.The sus time , as confRF), was calculated as follows.The removal efficiency of metal ions from the source phase, described by the recovery factor  was applied to measure the concentration of Hg(II) ions, the other metal ions concentrations were analyzed by flame atomic absorption spectrometry , whereas chloride and sulphate concentrations were analyzed by ion chromatography .The obtained values correspond to the average of duplicates with the standard deviation within 2%.o-NPOE), while concentrations of the carrier (KP) in the membrane ranged within 1–8 wt.% (0.01–0.30 M) based on the plasticizer’s volume. The main factors influencing the efficiency of Hg(II) ions separation during transport through PIMs include membrane composition and the selection of the right receiving phase . The eff3 groups. A suggested, the mercury–calix[4]pyrolle complex transported through the membrane is shown in The carrier is of substantial importance to facilitate the transport of Hg(II) ions through the membrane. This was certified with the results of blank experiments (in the absence of carrier), which proved insignificant flux across PIM to contain only the support and plasticizer. Therefore, within the membrane phase, the facilitated transport of mercury was conducted in the presence of the carrier (extractant) . The rem−3 µmol/m2s was obtained. Lower fluxes at higher carrier concentrations probably resulted from the saturation of membrane pores with metal complexes. An increase in the carrier content in the membrane resulted in a decrease in membranes permeability; thus, the value of initial Hg(II) ions flux was obtained probably due to an increase in the curve of the diffusion path of metal complexes caused by an increase in tortuosity factor in the plasticized membrane. The separation of mercury in the PIM was a 3-step process: (i) metal ions were transmitted from the source phase to the boundary layer of the membrane, (ii) the metal-extractant complex was formed at the source solution–PIM interface and (iii) the metal-carrier complex was transferred through PIM pyrrole as ion carrier. The porosity of the membrane is understood as the proportion of the liquid phase (plasticizer + solvent) on the membrane surface. The pores of the membrane in PIM are the inclusion of the liquid phase (the carrier solution in the plasticizer) into the CTA matrix, creating a transport route of various tortuosity. Thus, the degree of PIM porosity depends on the amount of plasticizer immobilized to the CTA matrix. Typically, such an inclusion has the shape of pores visible on the surface, which is confirmed by SEM and AFM photos for membranes containing The SEM images were made in order to observe the possible degradation of the surface and to determine the deposits produced after Hg(II) ion transport across PIM . − adducts or the metal–carrier complex formation. Evident changes in the membrane appearance after transport can be the effect of metal ion accumulation in the membrane phase [A comparison of surface microstructure shows the diversity of matrix materials of the membrane with calix[4]pyrrole derivative before and after the transport of Hg(II) ions across PIM. Crystalline structures of deposits observed in the membrane after the transport process are most probably the result of Hg(II)-calix[4]pyrrole-Clne phase . The SEMo-nitrophenyl octyl ether), as a representative of the phthalate esters group, is subject to hydrolysis, the extent of which increases with a pH increase or decrease and with longer contact times pyrrole derivative was of 25.26°. This value proves a hydrophilic character of the CTA membrane as no wetting contact angle above 90° was observed . The surThe investigation also included examining the influence of the concentration of hydrochloric acid in the source phase within the range of 0.01 ÷ 1.0 M on Hg(II) ions transported through PIM. Along with the increasing acidity in the source phase, the efficacy of mercury separation was increasing until reaching a maximum value of 91.8% at the HCl concentration of 0.1 M . The pH Among various properties, the greatest advantage of PIMs is the possibility of their reuse, which ensures its industrial usefulness . During What significantly affects the performance of mercury ions transport across PIMs can include the nature and composition of the receiving phase. With different strip agents, the percentage of transported Hg(II) ions under similar experimental conditions is listed in − adducts (included in the membrane phase) into the receiving phase.While applying 0.1 M NaCl as the receiving phase, the most effective Hg(II) ion transport through PIMs was reached compared to other strip agents. The sum of percentages of mercury ions in the source and receiving phases is not equal to 100; there can be some Hg(II) ions staying in the membrane, particularly when the stripping agent does not have enough tendency to release Hg ions completely from the Hg(II)-calix[4]pyrrole-Cl3, i.e., below the permissible value in treated wastewater in accordance with Polish legislation. Moreover, the RF values found for other constituents of wastewater were below 7%, which demonstrate the selectivity of the system for mercury ions , Pb(II), Zn(II), Cd(II) and Hg(II)), chloride and sulphate ions . Hg(II) ury ions .o-nitrophenyl octyl ether as the plasticizer. The highest Hg(II) ions separation efficacy of 91.8% was obtained at the concentration of HCl in the source phase of 0.1 M and when 0.1 M sodium chloride was used as the receiving agent. Moreover, the membrane was reusable and showed a good performance  in selectively removing mercury ions from the zinc smelting wastewater.The efficiency of mercury ion separation with the use of PIMs depends mainly on the acidity of the source phase, membrane’s elements (concentration of the carrier and plasticizer in the PIM) and selection of the appropriate receiving phase. The optimization of PIMs composition and selection of appropriate process parameters allow achieving their high efficiency and stability for the selective removal of mercury ions from industrial wastewater. The arrangement of the “optimal” PIM followed from our study was 19 wt.% of cellulose triacetate as the support, 4 wt.% of KP as the ion carrier and 77 wt.% of The separation of heavy metals in membrane processes with the use of PIMs can significantly improve the most technologically important operations of recovering metals from wastewater, thus solving the technical and economic problems of removing toxic pollutants from aqueous waste streams for the benefit of the natural environment.


Hybrid alkali-activated cements (HAACs), also known as cements with high percentages of alkali-activated supplementary materials, are alternative cements that combine the advantages of ordinary Portland cement (OPC) and alkali-activated systems. These cements are composed of a minimum of 70% precursor material and a maximum of 30% OPC mixed with an alkaline activator. This article evaluates the corrosion performance of reinforced HAAC concrete based on fly ash (FA) under exposure to chlorides . Its performance is compared with that of a binary alkali-activated cement (AAC) based on FA and granulated blast furnace slag (GBFS) . The tests performed on the concrete matrix correspond to the compressive strength and permeability to chloride ions. Using accelerated corrosion techniques (impressed voltage) and electrochemical tests after immersion in 3.5% NaCl, the progress of the corrosive process in the reinforcing steel is evaluated. The FA/OPC exhibit a better corrosion performance than the FA/GBFS concrete. At the end of the exposure to chlorides, the FA/OPC hybrid concrete presents the best performance, with a 49% lower corrosion rate than that of the FA/GBFS. Note that according to the polarization curves, the values of the proportionality constant B in the alkaline-activated concretes differ from the values recommended for concrete based on OPC. Howevermissions ,4,5. Formissions ,7.2O3 can be incorporated as an alternative to replace thermal curing [AAMs are produced through the chemical reaction of precursor material, an aluminosilicate source, and an alkaline activator. The precursor materials commonly used are fly ash (FA), metakaolin, natural pozzolans, granulated blast furnace slag (GBFS), and construction and demolition waste, among others ,9,10. Thl curing . From thl curing , and is l curing ,17.2O3 content not exceeding 10%, reactive silica content between 40% and 50%, and less than 5% loss on ignition (LOI)) [As mentioned above, FA is one of the most commonly used precursor materials for the production of AAMs. Regarding the use of FA in AAMs, certain specific characteristics have been recommended ) ,19. Howen (LOI)) , previouOne of the main durability problems faced by the components of civil infrastructure that has a great influence on their useful life is the corrosion of steel in reinforced concrete structures. To maintain the structures in a safe and functional state, high-cost repairs and maintenance are necessary. OPC-based concretes provide the necessary pH conditions to promote the passivation of the reinforcing steel; however, when they are exposed to chloride ions, the ions can diffuse through the cementitious matrix, and upon reaching a critical concentration, they can degrade the passive layer and initiate corrosive processes in the reinforcing steel that can result in a rapid deterioration of the structure ,22,23. Icorr), polarization resistance (Rp) and corrosion current (Icorr) for the steel embedded in the geopolymer concrete during the first three months showed that the passivation of the reinforcing steel was slightly lower than that of concrete made with OPC. Other studies have shown opposite results, stating that alkali-activated mortars or concretes based on FA have a protection similar to or better than that of reinforcing steels embedded in materials manufactured with OPC, achieving similar Icorr and Ecorr [Monticelli et al.  studied nd Ecorr ,30,31. Ond Ecorr ,32 evalund Ecorr  stated tnd Ecorr , who repcorr) lower than those of OPC concrete after 20 months of exposure to accelerated carbonation . Note that there are no reports on the corrosion performance of these hybrid concretes  in the presence of chlorides.Studies of these hybrid materials have mostly been carried out on pastes and mortars and focus on the mechanisms of hydration and the mechanical performance ,36,37,38This article evaluates the corrosion behaviour of the reinforcing steel of an HAAC based on FA  in the presence of chlorides. As a reference, binary AAC . To evaluate the corrosive process, two exposure methodologies were used: the accelerated technique known as impressed voltage and electrochemical tests , and Tafel slopes) after immersion in a 3.5% NaCl aqueous solution.To produce alkaline-activation systems, FA, GBFS and OPC for general use were used. The chemical compositions of the FA, GBFS, and OPC were determined with the X-ray fluorescence (XRF) technique using a Phillips MagiX-Pro PW-2440 spectrometer, and the results obtained are shown in The micrographs obtained by scanning electron microscopy (SEM) for each of the materials are presented in 2SiO3·nH2O with chemical composition of 32.34% SiO2, 11.81% Na2O and 55.85% H2O) and industrial grade sodium hydroxide  was used to obtain the appropriate molar ratios for each concrete produced.As an activator solution, a mixture of commercial sodium silicate  and relative humidity (RH) above 90%.To prepare the concretes, river sand with a fineness modulus of 3.1 and crushed gravel with a maximum particle size of 12.7 mm were used according to the ASTM specifications . Two typAcronal acrylic primer) was applied on the lateral face of the specimen to make this face impermeable to direct the entry of water. The tests were performed on cylindrical specimens (76.2 mm diameter and 152.4 mm height) at curing ages of 28 and 360 days. The values reported of compressive strength and resistance to water penetration correspond to the average of three specimens.The compressive strength tests were carried out according to the ASTM C39 standard using an ELE International testing machine with a capacity of 1500 kN at a speed of 1 mm/min until breakage. The resistance to water penetration (m) was evaluated following the standard procedure described in EMPA SIA 162/1  and ASTMCylindrical specimens 76.2 mm in diameter and 50 mm thick were used to evaluate chloride permeability. The test was carried out based on the ASTM C1202 standard . The val2. Several methods were used to determine the susceptibility to corrosion of structural steels in reinforced concrete:For the evaluation of the electrochemical behavior of the reinforcing steel embedded in the studied concretes, cylindrical samples with a diameter of 76.2 mm and a height of 152.4 mm were made. The structural steel bar (AISI 1020) was placed in the central part of the specimen. This reinforcement was covered with an anticorrosive epoxy film so that the exposure area was 100 mmImpressed voltage—The procedure was carried out based on the NT Build 356 standard , using a-Polarization curves (Tafel). At exposure times of 0, 180 and 360 days of exposure, the polarization curves were carried out to evaluate the electrochemical process and to determine by means of the Tafel slopes, the constant of proportionality B, according to Equation (1).a and βc correspond to the anodic and cathodic Tafel slopes, respectively.Immersion test—In this case, the reinforced concretes after curing for 28 days were exposed to two environments, immersion in drinking water and immersion in 3.5% NaCl aqueous solution, and the following tests were carried out to evaluate the corrosive process:-corr corrosion rate was calculated using the Stern-Geary equation Equation (2):Linear Polarization Resistance (LPR). Linear polarization resistance was determined at the end of each month of exposure, and the test was carried out for a total period of 12 months. The LPR test was performed following the ASTM G59 standard . The thrp corresponds to the linear polarization resistance. For the specific OPC, the recommended value B = 26 mV was used [A three-electrode electrochemical cell was used, where the working electrode corresponds to reinforcing steel, an Ag/AgCl reference electrode and a stainless-steel counter electrode located around the concrete. Overpotentials of −250 to +250 mV were applied. A Potentiostat/Galvanostat brand Autolab Instrument PGSTAT128N was used in the test.was used .7 s/m2. At 360 days of curing, the best behaviour is exhibited by the FA/GBFS concrete, which reaches a compressive strength of 62 MPa and a resistance to water penetration of 4.77 × 107 s/m2. On the other hand, the FA/OPC concrete exhibit compressive strengths of 41 MPa at 360 days of curing and a resistance to water penetration of 3.14 × 107 s/m2, surpassing by 100% the results obtained at the 28 days of curing.The compressive strength of the concretes FA/GBFS and FA/OPC at ages of 28 and 360 days of curing, as well as the resistance to water penetration (m), are included in In + and OH− [+ ions present in the pores of the material are expected to diffuse in the direction opposite that of the Cl− ions through the pore network, which can lead to a greater charge transfer during the test. Therefore, a greater ionic strength in the pore solution of the samples is expected to lead to higher charge values, which means that the values observed in the evaluated AACs could be higher than the chloride permeability in reality.In the interpretation of the data obtained by RCPT, it is important to take into account that this test is fundamentally a measure of the electrical conductivity of the concretes. Ionic transport depends to a large extent on the structure of the pore network in the cementitious matrix, while the electrical conductivity in the concrete is affected both by the structure of the pore network and by the chemical composition of the solutions in the pores ,54,55. I and OH− ,57,58. TTo analyze the corrosion susceptibility of the FA/GBFS and FA/OPC concretes, impressed voltage tests were carried out, through which the behavior against corrosion was rapidly evaluated. During the test, the electrical potential applied to the reinforcing bars attracts the negatively charged chloride ions from the aqueous solution of 3.5% NaCl to the concrete and towards the positively charged steel bars, thus initiating the diffusion process of chloride ions in the matrix and inducing the corrosive process . Due to + and OH− present in the pore solution of the alkaline activation concretes [oncretes ; coincidoncretes . The subThe FA/OPC concretes present a higher current intensity than the FA/GBFS at the appearance of the first crack, reaching values of 20 mA, as is presented in It is well known that the most reliable method for determining the degree of corrosion in reinforcing steel is a mass loss measurement. Therefore, to determine the mass loss of the corroded reinforcing steel, the concrete samples were transversely broken to extract the reinforcing bar. corr, the current density Icorr and the proportionality constant B were obtained by the extrapolation method from the polarization curves obtained in the Tafel test. These results are presented in corr values.+, OH−), this can cause a higher conductivity and therefore more negative potentials and higher corrosion densities. The electrical conductivity generated by these ions is related to moisture since it increases their mobility. Bastidas et al. [corr of mortars activated with FA in humid environments are more negative than those in dry environments. It is important to mention that the RH at which these tests were performed is on the order of 70% (corresponding to the atmospheric humidity of the region). Another factor mentioned in the literature that can affect the values of corrosion potentials and rates in alkaline activation systems is the pH of the pore solution; however, more studies are necessary to corroborate this effect [corr decrease, which indicates that the ionic conductivity is reduced. This behavior coincides with that observed in the impressed voltage test  and the cathodic curve (βc) Equation (1). The technical committee RILEM TC154 [corr calculations by means of the LPR technique for OPC concretes. According to corr by means of the LPR technique, the average of the B values obtained at exposure ages of 180 and 360 days of the FA/OPC and FA/GBFS concretes was calculated for the two environments evaluated. A B value of 14.6 mV ± 1.6 is obtained.The proportionality constant B was calculated from the slopes of the anodic curve . At the end of the exposure, the values of IThe visual inspection of the steels after exposure to chlorides for a period of 12 months does not reflect the severity of the conditions indicated by the results of the electrochemical measurements for the activated concretes, suggesting the need to modify the ranges used to evaluate the severity of corrosion in this type of concrete is needed.


China leads the world in the development and rollout of 5G network, yet less research has been done on the drivers of Chinese people’s adoption of 5G network, especially the specific role of national sentiments, such as the influence of patriotism on their attitude toward 5G network. The study obtained 804 effective online questionnaires from the respondents of various ages, genders, areas, and educational levels. The results based on the structural equation modeling (SEM) analysis showed that patriotism was an antecedent to Chinese users’ cognition of the conditions provided by the government and telecom operators and the extent that users were influenced by media and surrounding people, which in turn increased users’ expectations of the performance of 5G network and their confidence in adapting to 5G network, and resulted in an increased willingness to use 5G network. This research helps to understand the role of patriotism, which is an emotional factor, in stimulating Chinese users’ attitudes toward 5G network at the time when 5G network is putting into large-scale commercial use in China. Ad Hoc in Japan). Many countries have regarded the mobile communication industry as a strategic battlefield for establishing national competitive advantage. It is no exaggeration to say that whoever dominates 5G stands on the commanding heights of the future economy.Advances in information and communication technologies are fundamental to the future smart cities . The curThe Chinese government regards 5G as key to China’s economic development and the development of its technology industry. The 13th 5-Year Plan described 5G as a strategic emerging industry and a new economic growth point . The ChiThe impact of patriotism on user’s behavior is an important issue in user’s behavior research e.g., . The effThis study is based on three motivations: the need of the government to arouse the enthusiasm of the public, the need of operators to stimulate the purchasing sentiment of consumers, and the need to clarify the relationship between several variables in the unified theory of acceptance and use of technology (UTAUT) model. To be specific, many countries regard 5G as the key to building competitive advantages and standing at the commanding heights of the future economy. All levels of government must face the problems of how to grab 5G development opportunities through rapidly mobilizing the enthusiasm and self-confidence of the people of the country. Meanwhile, the competition in the 5G market will be far more intense than that in previous telecommunications markets. For the purpose of surviving and reaping rewards in this increasingly fierce market environment, operators must analyze consumers’ attitudes toward the 5G network environment from the perspective of their sentiments. In addition, the effect of the four predictive UTAUT factors on behavioral intention has usually been tested separately, and very few pieces of research have explored their inner correlations.With these motivations in mind, we aim to test the factors that influence Chinese peoples’ intention in adopting and purchasing 5G network based on integrating patriotism into the UTAUT model. This paper contributes to the following:1.Constructing a theoretical model that explains the drivers of Chinese people’s adoption of 5G network;2.Providing useful insights into the transformation of patriotism and national sentiments into user’s behavior intention;3.Distinguishing between predicted factors and affected factors of the UTAUT model in terms of the Chinese people’s attitude toward the 5G network;4.Helping governments and relevant departments to grasp user needs in the future of 5G evolution process.The existing studies on the use of communication technology mainly focused on the convergence and obedience of people to norms of social public behavior e.g.,  and percThe unified theory of acceptance and use of technology, proposed by The unified theory of acceptance and use of technology has been applied and tested in a variety of studies in the field of communication and information technology, including E-government systems and services , online H1: Chinese people’s perceived effort expectancy of using 5G (H1a), performance expectancy of 5G (H1b), and social influence (H1c) and facilitating conditions for 5G use (H1d) enhance their intention to use 5G.Patriotism represents an individual’s strong feeling of loyalty and attachment to his country without showing hostility toward other countries . A patriPatriotism is essentially a loyalty to the country, with an intense desire for the prosperity of the country. Subconsciously, Chinese people often associate patriotism with the rise of national brands and a strong national economy . The ChiH2: Chinese people’s patriotism enhances their intention to use 5G.Facilitating conditions is the users’ perception of the extent to which an organization or related infrastructure supports the usage of a technology , which iAs the Chinese people’s patriotism rises along with the gradual increase in national strength and economic prosperity, the people’s trust in the ability in laying out infrastructure of the government and the productive ability of enterprises is increasing. According to the 2019 Edelman Trust Barometer, a report released by Edelman, the world’s largest public relations enterprise, China leads the rest of the world in terms of the Chinese people’s trust in their government, enterprises, media, business, and non-governmental organizations . It is rPatriotism may lead the Chinese people to place more trust in the capacity and efficiency of the government and the involved enterprises in the planning and construction of 5G, may in turn increase the Chinese people’s recognition of the day-to-day benefits that 5G brings, and may improve their confidence in integrating 5G into their lives. Hence, we propose the following hypotheses:H3: Chinese patriotism enhances their perceived facilitating conditions for 5G.H4: Chinese perceived facilitating conditions for 5G enhance their perceived effort expectancy (H4a) and performance expectancy (H4b) of 5G.H5: Facilitating condition mediates the relationship between Chinese patriotism and perceived effort expectancy (H5a)/performance expectancy (H5b) of 5G.Numerous media reports about 5G have emerged since 2017. For example, reports have claimed that 5G’s high-speed and low-latency technology innovation will be interconnecting everything ; that thNational pride is one of the reasons why China attaches so much importance to 5G technology . WheneveSocial influence refers to the user’s perception that relatives, friends, colleagues, and acquaintances feel that he or she should use a certain technology and that the media advocates the use of certain products . This stNews about 5G or related enterprises is often seen on mass media and social media, and for the Chinese, 5G is a thing that is certain to enter everyone’s life in the near future. Across society, from government to business to media to individuals, everyone is discussing 5G . Word ofPatriotism may lead the Chinese people to be more influenced by the media’s promotion of China’s leading technology as well as by praise by the people around them for national enterprises such as Huawei. This in turn may increase the Chinese people’s recognition of the day-to-day benefits that 5G brings and may improve their confidence in integrating 5G into their lives. Hence, we propose our final hypotheses as follows.H6: Patriotism enhances the extent to which social influence affects Chinese users.H7: Social influence enhances Chinese perceived effort expectancy (H7a) and performance expectancy (H7b) of 5G.H8: Social influence mediates the relationship between Chinese patriotism and perceived effort expectancy (H8a)/performance expectancy (H8b) of 5G.The conceptual framework of this study is shown in This research utilizes online survey to collect the self-report data of Chinese users, for the purpose of understanding their perception of expectancy brought by 5G effectiveness and its related external environment as well as their willingness in purchase and use 5G network.Patriotism (α = 0.881) was adapted from n = 390) were young people between 18 and 32 years old, and one quarter of them (n = 204) were middle-aged people between 33 and 47 years. About four-fifth of respondents (n = 638) were well educated, with a college’s degree or above. More than one-third of respondents (n = 300) and one-quarter of them (n = 201) live in the first-tier and second-tier cities, respectively. Almost one-third of the respondents (n = 255) have experienced 5G network.The study was conducted on WJX, China’s largest non-proprietary online survey platform, during July and August in 2020. WJX has an e-panel comprised of more than 2.6 million members. To avoid repeats, respondents with the same computer/mobile phone can access the survey one time only. A total of 804 respondents, including 421 females and 383 males, completed the questionnaire. Almost half of the respondents (p = 0.006) and performance expectancy  have significant effect on Chinese users’ purchase and use intention of 5G network, supporting H1a and H1b. But contrary to H1c and H1d, neither social influence  nor facilitate conditions  could directly affect 5G usage intention.Structural equation modeling (SEM) approach by Mplus was used to test the proposed model . The modp = 0.000) and the extent to which social influence affects them . Meanwhile, patriotism could not directly affect Chinese usage intention of 5G , and H2 cannot be supported.Following, we tested the effects of patriotism on social influence and facilitation conditions. In support of H3 and H6, Chinese patriotism exerts significant effects on their perceived facilitating condition for 5G  and performance expectancy . Meanwhile, in support of H7, the extent to which social influence affects Chinese exerts positive effects on both effort expectancy  and performance expectancy . The results of the standardized model are shown in Then, we examined the effects of social influence and facilitating conditions on effort expectancy and performance expectancy separately. In support of H4, Chinese perceived facilitating conditions exert positive effects on both effort expectancy  and the 95% BC confidence interval of the mediation effect from patriotism to performance Expectancy via Facilitating Conditions did not include zero , in support of H5, that facilitating conditions mediates the relationship between patriotism and effort expectancy/performance expectancy.Mplus was utilized to implement the mediation effects test. Then, 5,000 bootstrap samples recommended by via social influence did not include zero  and the 95% BC confidence interval of the mediation effect from patriotism to effort expectancy via social influence did not include zero , in support of H8, that social influence mediates the relationship between patriotism and effort expectancy/performance expectancy. Likewise, the 95% BC confidence interval of the mediation effect from patriotism to effort expectancy Finally, this research tested whether there were significant differences in the hypothesized path model in respondents with/without experience of using 5G network, to help understand whether the proposed model could be used to understand the true intention of users when 5G is put into large-scale commercial use in China in the future.To compare these two groups, a multi-group analysis by Mplus was performed. In this analysis, each causal path was constrained equally across both groups at a time, and a model with each constrained path was compared with the completely unconstrained model. If the AIC and BIC values of the constrained model are significantly worse than that of the unconstrained model, the constrained path coefficients are identified as significantly different between the two groups . For AICThe results show that the fitting information of the SEM model with constrained regression coefficients  is lower than that of the model with unconstrained regression coefficients . It means that there is significant difference between people with/without 5G usage experience in terms of extent of the proposed model in explaining their 5G usage intention. It indicates that proposed model based on the perspective of the combination of UTAUT and patriotism is more suitable for the people who have real usage experience of 5G network.From the above analysis, we can draw the conclusion that the patriotism of Chinese people improves their perception of the facilitating conditions and social influence of 5G network. In addition, both social influence and facilitating conditions are drivers of Chinese people’s perceived performance expectancy and effort expectancy of using 5G network, and the latter two variables are predictors of their purchase and use intention toward 5G network.Further, social influence and facilitating conditions separately mediate the relationships between patriotism and performance expectancy/effort expectancy. This indicates that patriotism first enhances Chinese people’s perception of the facilitating conditions and the extent to which social influence affects them, in turn strengthening their expectations of the performance of 5G and of their ability to adapt to 5G network.This research shows that, in China, patriotism first affects people’s perception of government and enterprise capabilities and the extent to which they are influenced by the media and people around them. This in turn affects expectations of 5G’s function and expectations for adapting to 5G and ultimately affects 5G use intentions.The complete path from patriotism to purchase and use intention of 5G network, as verified in this research, provides a full understanding of how Chinese patriotism exerts an influence on the four drivers of UTAUT, which in turn leads to usage intention of 5G network. The mechanism can be explained as follows. Feelings of patriotism improve the trust that Chinese people have in the facilitating conditions provided by the government, technology enterprises, and telecom operators and enhance the extent to which people are influenced by media and surrounding people in terms of promoting 5G network and its related products. This in turn strengthens people’s confidence in adapting to the future 5G world and their trust in the performance of 5G network. Finally, people’s willingness to use 5G network is strongly based on their high expectancy.Patriotism is a strong feeling that has long been inherent to the Chinese nation. Specifically, for Chinese citizens who have suffered and persevered during the past 100 years, patriotism is a potent agent with the power to influence society and current events. The Chinese people’s strong expectation that 5G will deliver convenience and other benefits to their life and their confidence in their ability to integrate into a world where all things are connected by 5G are both inseparable from the patriotism and national pride inspired by the country’s strength and economic prosperity.Patriotism, which is complemented by national pride and a spirit of working for national advancement, makes Chinese people believe that the government and relevant institutions will successfully deploy 5G facilities nationwide. The strong social management capabilities of the country and the Chinese telecom operators enhance the Chinese people’s recognition of the stability and wide coverage of 5G as well as their confidence in its smooth usability.Patriotism also renders them more susceptible to promotion of 5G network in the media and by word-of-mouth. The 5G enterprises represented by Huawei often emphasize the struggle for national interest in its public relations strategies which greatly incites the patriotism of the people. For example, since the first half of 2019, the US-sponsored trade sanctions against Huawei have become one of the hottest topics on the Internet in the country of the whole network, one that has quickly stimulated the nationalist sentiments of the Chinese people and contributed to the improvement of Huawei’s local reputation .This paper presents new insights into the extent to which patriotism can be transformed into user intentions. Specifically, this paper uses empirical methods to verify the antecedent variables of 5G use intentions in China’s domestic environment, including patriotism and UTAUT. It embeds Chinese patriotism into the evaluation and perception of the functional utility and external environment of 5G in China, establishing a UTAUT-based use intention evaluation model, helping explore the factors affecting Chinese users’ use intention of the coming 5G networks, and providing a new perspective for research into 5G services.This study found that social influence and facilitating conditions can both be the drivers of the two aspects of expectancy. It indicates that, on the one hand, Chinese people’s expectation and estimation of an upcoming large-scale universal technology are boosted by their cognition of the capacity and effectiveness of the government and national enterprises, and on the other hand, the Chinese are easily influenced by the opinions of the people around them and also trust the media when considering the adoption of a technology that is closely related to all aspects of life. This is an innovative restructuring of the UTAUT, providing new evidence for future research based on this concept.This study collects empirical data on user’s perceptions of 5G in terms of government layout, corporate R&D, media promotion, operator building, and 5G usage intentions for understanding and predicting the future use of 5G networks in a large scale of people. The study provides decision-making references and data support for 5G use in various fields.In terms of facilitating conditions and social influence, operators can organize various activities to promote 5G technologies and related products in society, to introduce the functions of 5G networks, and to enable the public to fully understand the improvements in quality of life that 5G technologies may bring. Governments and operators can encourage people to recognize and adopt 5G network through word-of-mouth communication on media and in real life. At the same time, 5G R&D companies can strengthen cooperation with governments and telecom operators to expand the uses of 5G network, such as developing 5G-related technologies for education, medical care, old-age care, transportation, and other fields. In addition, industry R&D into 5G network can strengthen connections with 5G-related products and organizations, develop uses and products related to 5G in all aspects of life, and promote the accessibility of 5G technologies in various fields.The localization research carried out in this paper provides useful insights into the transformation of patriotism and national sentiment into consumer’s behavior intentions. Users’ willingness to adopt 5G technology and related products involves complex psychological behavior, which needs to be systematically researched in multiple dimensions. The future research could test more complex variables that may have effects in stimulating consumers in adopting and using network technology. In addition, with the large-scale commercialization of 5G networks in more and more countries, studies examining the relationship between patriotism and consumer’s purchase intentions or behaviors should consider the effects of brand characteristics , to obtain information on consumer attitudes that are more relevant to national markets.The data that support the findings of this study are available from the ZK, upon reasonable request.All authors listed have made a substantial, direct, and intellectual contribution to the work, and approved it for publication.


Calcium carbonate induced by microorganisms can quickly fill and cement sand particles, thereby effectively reducing the potential for the liquefaction of sand. This process could represent a new green approach to the liquefaction treatment of saturated sand and has good prospects for application. However, owing to the diversity of microbial activities and the heterogenous spatiotemporal distribution of bacterial nutrient seepage in sandy soil foundations, the resultant complex distribution of calcium carbonate deposition in a sandy soil foundation can lead to differences in solidification strength and improvement effect. To understand the influence of earthquake action on the liquefaction resistance of saturated sand treated by microorganisms, and to evaluate the effect of microbial technology on sand liquefaction prevention under dynamic load, this study simulated the dynamic stress conditions of saturated sand under shear waves, using the world′s first centrifuge shaking table (R500B), which realizes horizontal and vertical two-way vibration. On the basis of spatial heterogeneity of microbial mineralization after centrifuge shaking table tests, the effect of microbial strengthening on liquefied sand was analyzed, and the spatial distribution of calcium carbonate mineralization was examined. The results showed that the distribution of microorganisms in the solidified soil exhibited obvious spatial heterogeneity with a significant edge effect. Although microbial mineralization effectively improved the liquefaction resistance of saturated sand, a sudden change in the process of calcium carbonate deposition altered the cementation of the sand with depth. Moreover, the curing strength had obvious complexity and uncertainty that directly affected the shear stiffness of the soil under dynamic load, and this constitutes one of the reasons for the degradation of shear stiffness of sand during liquefaction. The derived conclusions could be used as a reference for engineering applications of microbial treatment of a liquefiable sandy soil foundation. Sand liquefaction induced by an earthquake is a common sudden geological event. It is one of the causes of potentially fatal earthquake-related damage, such as the uneven settlement of building foundations and structural damage. Research and engineering circles in China and internationally have long attached great importance to this phenomenon. With the 2008 Wenchuan earthquake in China, large-scale severe liquefaction occurred , wherebyA centrifuge shaking table can realistically simulate the stress conditions of a prototype stress field, accurately reproduce the dynamic response of the prototype under the actual stress conditions, overcome the influence of simplified assumptions on the soil properties in theoretical calculation, and reduce the problems of high cost and long testing times in prototype observation . ConsequThe microbial grouting method is an innovative approach that is mainly used to improve the shear strength and stiffness of sandy soil, using the growth, migration, and propagation of microorganisms in porous media. Different from calcium carbonate synthesized by using general chemical methods, calcium carbonate crystal particles formed by microorganisms are small, have different shapes, and have strong cementation and filling effects. They can cement loose sand particles into a unit with certain mechanical properties that can substantially increase the strength and bearing capacity of a soft sand foundation and reduce its permeability. The strength and reaction speed of microbial solidified sand are controllable, and application of the technique has the advantages of being rapid and efficient, using non-toxic products, and having a clear mechanism. Thus, it has become the leading technology used for treatment of liquefiable sand. Today, with increasing ecological awareness, microbial rock/soil modification technology demonstrates strong competitiveness .As a new type of foundation treatment technology, microbial grouting reinforcement has promoted advances in the field of soil strength solidification and modification ,26. HoweGS) of the sand is 2.61. The grading curve is shown in Cu) is 1.655.The sand used in the model testing was Jinjiang XiFeng standard sand. Sporosarcina pasteurii, which is a type of chemotrophic bacteria. The cells were rod-shaped, 2–3 µm in length, 0.5–1.5 µm in diameter, Gram-positive, and the spores were round.The bacterial strain used in the experiment was 600 of the bacterial solution was 2.293 on average, and the urease activity was 2.0 ms/min/cm on average. The nutrient used in the test was Ca(CH3COO)2.To prepare the microbial grouting fluid, optimized #136 medium was prepared by adding 20.0 g of yeast powder, 10.0 g of ammonium sulfate, and 1.0 mL of nickel chloride for every 1.0 L of water. Sodium hydroxide solution was added to adjust the pH of the medium to 9.0, and the medium was sterilized at 120 °C for 40 min. After inoculation, the bacterial culture was placed in a shaking incubator at 30 °C and shaken at 170 rpm for 24 h ,28,29,302. To ensure that the pore pressure did not dissipate too quickly during the vibration process, the time-similarity ratio under the action of seepage was close to the similarity ratio under the action of the dynamic force of 1/n, making the simulation results more accurate. The saturated solution used in the test was hydroxypropyl methyl cellulose, with a mass concentration of 0.48% and a viscosity of 30 times that of pure water.In the centrifugal simulation test, the time-similarity ratio under dynamic action was 1/n, and under the condition of the saturated sample, the time-similarity ratio in the seepage process was 1/nThe Lxj-4-450 large-scale geotechnical centrifuge model test machine and the R500B shaking table a of the The model box comprised a stacked ring model box constructed from aviation ultra-high-strength light aluminum alloy b, with a3COO)2 solution at a low concentration of 0.5 mol/L and then poured quickly into the sand sample. The microorganisms were then cultured in situ for 24 h in the sand sample. Subsequently, the nutrient salt of the mixed solution of Ca(CH3COO)2 and urea with the same concentration of 0.5 mol/L was added at a low speed.The bacterial solution with high biological activity after laboratory mutagenesis was mixed with Ca mg/L. The supernatant was poured out, and the flask was weighed again (M2) in grams. Finally, the remaining sandy soil was dissolved in 100 mL of dilute hydrochloric acid and shaken, and the Ca2+ concentration in the supernatant (C2) mg/L was determined after the reaction was completed. The calcium carbonate content of the sand was calculated according to the relation [c2 × 0.1 − C1 × (M2 − M1) × 0.001]/0.4.To determine the calcium carbonate content, a sample of sand was weighed and placed in an oven at 60 °C for 24 h. Then a 2 g sample of dried sand was placed into a 150 mL conical flask, and the total weight (M1) in grams was determined. Next, 100 mL of deionized water was poured into the conical flask, which was shaken, and then the CaThe inverse distance weighted spatial interpolation method ,32,33 waThe basic principle is as follows. Suppose a series of discrete points are distributed on a plane and the coordinate values are known to be Xi . Then U(x) can be interpolated by using the distance weighted value to satisfy the following relationship:The purpose of the interpolation step is to calculate the distance from the unknown point to all points, to calculate the weighting of each point, and then to calculate the value at the interpolation point according to Equation (1).The microbial determination results in the sample were calculated according to Equation (1), and the planar spatial distribution maps of the microorganisms in the sand layers at depths of 5, 10, 15, 20, 25, and 30 cm downward from the sand surface were drawn . The amplitude of the peaks and valleys shows the heterogenous distribution of the microorganisms in the sandy soil foundation. It can also be seen that the numbers of microorganisms in the 5 and 10 cm sand layers are notably higher than in the other layers. Similar to the discussion on the spatial heterogeneity of the microbial distribution, maps of the distribution of calcium carbonate were drawn . The pressure difference between the two also increased with the increasing depth during the grouting process. Moreover, the boreholes on the pipe used for distributing the grouting fluid were all buried 3 cm below the surface of the sand layer. Owing to the pressure of the peristaltic pump on the flow of grouting fluid in the pipe, the closer the pipe is to the surface of the sand foundation, the easier it is for the grouting fluid to flow out. Accordingly, the pressure immediately decreases after the fluid flows out, resulting in a greater concentration of the microbial grouting fluid in the upper surface layer in comparison with the middle and lower layers.A comparison of In terms of the biological reinforcement test, it is important to resolve the problem of consistency in the relative compactness of the falling sand layer in the model. It is also important to ensure uniformity of the methylcellulose saturated solution in the porous medium  because these affect the success or failure of the test.The medium-strengthening microbial reinforcement scheme substantially improves performance in the prevention of liquefaction of sand (for a foundation of approximately 9.6 m) and improves the shear stiffness of sand to a certain extent.3COO)2 is considered most suitable for the treatment of liquefied sand foundations.The type of calcium salt has an important influence on the microbial treatment of liquefied sand. Under the same conditions, Ca.Zeghal and Elgamal  proposed2.Microbial mineralization of saturated sand has obvious uneven distribution and a significant edge effect. The treatment effect would be further improved by reasonably adjusting the batch of microbial grouting, optimizing the length of the grouting pipe, and optimizing the distribution of the injection port on the basis of the actual status of the liquefiable sand in the engineering application.


Coal dust pollution poses a serious public health threat. This study aimed to investigate the feasibility of creating a coal dust suppressant using molasses, a byproduct of the sugar industry. We studied the effects of a molasses solution of varying concentrations  to 40%) on the moisture, bonding, and wind erosion properties of coal dust. Overall, the effectiveness of the molasses increased with their concentration, and it manifested itself in the following way: (1) the molasses improved the anti-evaporation ability of wet coal dust. For example, the evaporation mass of the coal dust wetted using a molasses solution decreased by 82.8%; (2) molasses effectively agglutinated coal dust; (3) molasses can effectively decrease the surface tension and increase the viscosity of the wetting solution. The surface tension of the molasses solution reached 41.37 mN/m and the viscosity increased to 6.79 mPa·s; (4) molasses can significantly suppress the wind erosion of deposited coal dust, with its wind erosion mass decreasing 99.1%; finally, (5) the effectiveness of molasses at suppressing coal dust was discussed at a molecular level. This study highlights the feasibility of a low-cost and environment-friendly dust suppressant in coal mines. The control of coal dust is of great significance in ensuring the occupational health and safety of coal workers. The rapid development of science and technology has become synonymous with improved living standards for many parts of the world, and these improved living standards have been accompanied by an increase in energy demand ,2,3. WitDust control technologies in underground coal mines can be divided into physical and chemical dust suppression . ChemicaIn recent years, numerous studies have been conducted to develop low-cost and environment-friendly chemical dust suppressants. Using plant extraction technology, Zhang et al.  developeThe use of industrial byproducts to prepare dust suppressants is an effective method for reducing the cost associated with developing chemical suppressants. Molasses is a by-product of sugar production and is produced worldwide ,19. ManyThe objective of this study was to explore the suppression characteristics of molasses solutions on hydrophobic coal dust (HCD). This objective was achieved in three ways: (1) the moisturizing and agglutination performance of molasses solution on the HCD was determined; (2) the properties of the molasses solution were tested with various concentrations; and (3) the dust suppression efficiency of molasses on the HCD was measured using wind erosion experiment. Finally, the suppression mechanism of molasses solution on coal dust was discussed, and methods were proposed to improve the preparation of molasses-based coal dust suppressants. This study is significant for the development of low-cost and environment-friendly dust suppressants in coal mines.(1)MolassesThe sugarcane molasses used in this study were purchased from Jinqianwan Molasses Co., Ltd. . The composition and content of sugarcane molasses are listed in (2)Coal dust sampleso) were tested following ISO 7404-1:2016 and ISO 7404-1:2016, respectively. The results are presented in Following GB/T 482-2008, the coal explored in this study was sampled from an underground mining site located in Datong City, Shanxi Province, China. The proximate contents of the coal samples were measured according to GB/T 212-2008. The maceral composition and vitrinite reflectance Evaporation parameters of the MWCDM g of MWCD was placed into a glass dish with an inner diameter of 8.0 cm (the mass of the dish is X g); next, the dish was exposed to a room temperature condition ; the mass of the dish was then tested per hour and recorded as nM , and the moisture evaporation mass could then be calculated following Equation (1). Subsequently, taking the time as the abscissa and the evaporation mass as the ordinate for drawing, the data were linearly fitted using the least square method, and the slope of the fitted linear is the evaporation rate (g/h).nm is the evaporation mass of the MWCD at time n (g); M is the mass of the MWCD before evaporation (g); nM is the total mass of the MWCD and dish (g), and X is the mass of the dish (g). First, the coal blocks sampled from the underground mining site were broken and milled using a ball mill machine. Coal particles with a size of less than 75 μm (200 mesh) were then screened. The coal dust was then mixed with the molasses solutions  at a 2:1 mass ratio. The two elements  were stirred slowly to ensure full mixing. Once this was complete, the MWCD sample was obtained. The evaporation parameters of the MWCD were measured as follows: (2)Moisturizing rate test for MDCD.tM is the mass of MDCD at time t (g); M0 is the mass of MDCD before moisturizing (g); ∞M is the maximum moisturizing mass of MDCD (g/g); and β is the evaporation rate parameter of MDCD. The MWCD was placed into a plastic dish with an inner diameter of 8 cm. The dish was then placed into an oven at a temperature of 100 ℃. The mass of the dish was measured per hour, and the mixed dry coal dust (MDCD) was obtained when the mass no longer changed. The plastic dish was then removed and the MDCD was placed into an oven, in which the temperature and relative humidity could be adjusted. The moisturizing parameters of the MDCD were measured at a temperature of 25 ℃ and various relative humidities . The mass of the dish was measured every 30 min for 4 h; after that, the maximum moisturizing mass (g) and moisturizing rate parameter were calculated according to the Weibull mode following Equations (2) and (3) : (2)Mt=MIn this study, to evaluate the agglutination performance of molasses solutions on coal dust, the maximum compressive strength of an MDCD block released from a plastic dish was tested, as shown in (1)Surface tension testsSurface tension has significant effects on both the evaporation characteristics and the wettability of the liquid . The pen(2)Contact angle testsWettability is an important parameter for evaluating the performance of coal dust suppressants because most coal dust is hydrophobic ,30,31, a(3)Viscosity testsViscosity is a key parameter that affects the agglutination and fluidity properties of a solution ,34, thus(4)Evaporation rate testsThe evaporation rate of the solution determines whether the solution can sustainably moisturize a substance ,36. TherAccording to , the supFor the wind erosion test, a fan was placed horizontally to the test sample, and the wind speed at the surface of the test sample was 5 m/s (the maximum wind speed in underground return roadway). This speed was controlled by adjusting the distance between the fan and the test sample. The test time was 5 min, and the mass of the test sample was measured before and after the wind erosion test, and the amount of airborne particulate matter (PM) with a particle size less than 10 μm (PM10) was counted during the test at 1 m behind the test sample using a particulate matter quantity tester (FULKE 985). From this test, the wind erosion mass (Δm) and the cumulative number of PM10 particles were obtained to characterize the suppression efficiency of the molasses solutions on coal dust. (1)Wind erosion massm0 and m1 are the masses of the test sample before and after the wind erosion test (g), respectively.The wind erosion mass (Δm) is a quantity that represents the mass of the test sample before and after the wind erosion test. The quantity can be calculated as follows: nP is the Δm reduction percentage of the molasses solution with a concentration of n (%) over that of pure water without molasses (%); and Δmn and Δmw are the wind erosion mass (g) of the molasses solution with a concentration of n and pure water, respectively. To analyze the suppression efficiency of molasses solution on the test samples, the Δm reduction percentage (P) of the molasses solution over that of pure water (0% molasses) was computed using Equation (5).(2)Cumulative number of PM10 particles.nC is the relative percentage of the cumulative number of PM10 in the test sample sprayed with the molasses solution with a concentration of n compared with that of the test sample sprayed with pure water (%); and cw and cn are the cumulative number of PM10 in the test sample sprayed with pure water and the molasses solution with the concentration of n, respectively. The FULKE 985 apparatus used in the wind erosion test can measure the number of particles in various sizes . To characterize the suppression efficiency of molasses solutions on coal dust, the relative percentage of the cumulative number of PM10 particles between the molasses solution and pure water was calculated using Equation (6).i is the number of particles with a particle size of i . Note that the cumulative number of PM10 particles is the total number of particles with sizes of 0.3, 0.5, 1.0, 2.0, 5.0, and 10.0 μm. It can be computed using Equation (7).(1)Evaporation parameters of the MWCDThe evaporation parameters of the MWCD, including the evaporation mass and evaporation rate, were measured, and the results are shown in (2)Moisturizing characteristics of the MDCDThe moisture characteristics of the MDCD were measured at various relative humidity values, and the results of the moisturizing mass variation with time are shown in 2) large than 0.90 in three relative humidities; second, in higher relative humidity, the molasses make a more apparent improvement in terms of their maximum moisturizing mass of coal dust. At 70% relative humidity, molasses had a limited effect on the maximum moisturizing mass of coal dust at concentrations less than 30%, whereas, at 90% relative humidity, molasses showed an apparent improvement in the maximum moisturizing mass of coal dust at low concentrations. Therefore, it can be concluded that molasses has a more significant improvement in the moisturizing ability of coal dust in a space with higher relative humidity. It can be observed from Within the context of suppressants, the moisturizing rate is a key parameter for assessing the performance of a material. As shown in In summary, the concentration of the molasses solution has a significant effect on both the maximum moisturizing mass and the moisturizing rate of the MDCD, and the relative humidity of the surrounding environment can improve the maximum moisturizing mass of the MDCD and had a limited influence on the moisturizing rate of the MDCD. The agglutination performance of a solution is highly related to the efficiency of the secondary flying of coal dust . Therefo2 = 0.99, and at 40% molasses concentration, the maximum pressure reached 171.21 N, which is 148.9 times that of pure water. These results indicate that the molasses solution has a significant agglutination effect on the coal dust. Therefore, molasses could be applicable in the field in terms of suppressing secondary-flying dust in coal mine roadways.The maximum pressure of the coal dust block b was meaTo fully understand the moisturizing and agglutination functions of molasses solutions on coal dust, the physical properties of molasses solutions with varying concentrations were measured, including surface tension, wettability, viscosity, and evaporation parameters. These results are detailly described in the following subsection. (1)Surface tension and wettability of molasses solutions2 = 0.92; the surface tension decreased to 41.37 mN/m at 40% molasses concentration, which reduced by 43.07% lower than that of pure water (0% molasses concentration). Owing to the hydrophobicity of most coal dust [oal dust , reducin(2)Viscosity of molasses solutions2 = 0.99; at 40% concentration, the viscosity of molasses solution reached 6.79 mPa·s, which is 5.43 times that of pure water. That is, adding molasses to water can increase the viscosity of the solution, which reduces its fluidity and spray properties. Therefore, the concentration should be controlled when preparing molasses-based coal dust suppressants to reduce their influence on solution viscosity. Viscosity is an important parameter that affects the fluidity and spray properties of liquid . The con(3)Evaporation parameters of molasses solutionsThe anti-evaporation characteristics of the dust suppressant solution are the key reasons for the enhanced water retention of dust. The evaporation parameters of the molasses solutions at room temperature are shown in To further analyze the effect of molasses concentration on the evaporation properties of the solution, as shown in 2 = 0.95, and the Δm values of the coal dust samples sprayed with 20% and 40% concentration molasses are 0.22 g and 0.02 g, which reduced 90.0% and 99.1% compared with that of pure water, respectively. This result indicates that molasses has a significant suppression effect on the wind erosion of coal dust, and its suppression efficiency largely depends on the molasses concentration. To investigate the suppression performance of molasses solution on the secondary flying of coal dust, in this section, a wind erosion test is conducted for coal dust sprayed with molasses solutions. 2 = 0.99. The PM10 number of the coal dust sample sprayed with 5% and 40% molasses solutions was reduced by 76.9% and 91.2%, respectively, compared with that of the coal dust sprayed with pure water. This result well verified the data shown in To reveal the effect of the moisturizing and agglutination parameters on the dust suppression efficiency, the wind erosion mass was used as the dust suppression parameter, and the relationships between the evaporation rate of the MWCD, the maximum moisturizing mass of the MDCD, and a maximum pressure of the agglutination coal block with the wind erosion mass were established and analyzed in this section. 2 = 0.77 and exponentially decreases with R2 = 0.99, respectively. That is, improving the moisturizing ability of coal dust has a positive effect on preventing wind erosion and the secondary flying of coal dust, but the effect is limited. Specifically, after the moisturizing performance of coal dust reaches a certain point, the suppression effect will not be improved by further enhancing the moisture ability. 2 = 0.96. This result indicates that the agglutination effect could directly affect the wind erosion resistance of coal dust, and the higher the maximum pressure, the stronger the bonding effect and the more significant the dust suppression efficiency. Based on the above results, we can conclude that the suppression effect of molasses on coal dust can be primarily attributed to enhancing the moisturizing and bonding properties of coal dust, and the bonding effect is the dominant factor. In this study, the feasibility of using molasses as a coal dust suppressant was evaluated through the lens of experiments. The results showed that molasses can significantly improve the moisturizing ability of coal dust and strongly bond coal particles. Through these two effects, the molasses solution has a remarkable suppression effect on the secondary flying of coal dust caused by wind erosion. In this section, we place our results within the context of published literature and discuss their implications.Molasses contain a lot of carbohydrates, such as sucrose, glucose, and fructose, among which the sucrose content can reach approximately 48.8% . SucroseIn addition, molasses also contains plenty of ash (approximately 13%) , which c2 and MgCl2 after water evaporation. CaCl2 and MgCl2 can form CaCl2·xH2O and MgCl2·xH2O, respectively, by absorbing moisture in the air [In addition, molasses contains a few metal ions, such as Ca, Mg, Na, and K, and trace chlorides , and the the air ,40. TherMolasses solutions exhibit significant agglutination properties for coal dust. As shown in As shown in In summary, in this study, we found that molasses could effectively improve the moisturizing and agglutination properties of coal dust. Under the action of these two characteristics, the molasses solution has significant wind erosion resistance to the deposited coal dust. At the same time, molasses solutions have some disadvantages in preventing coal dust, such as poor wettability and high viscosity. Therefore, the wettability and viscosity should be fully improved when developing a coal dust suppressant using molasses. (1)Molasses can improve the anti-evaporation ability of wet coal dust. The evaporation mass of the MWCD experienced three stages as the molasses concentration increased from 0% to 40%, and the evaporation mass decreased by 82.8% at 40% concentration than that at 0% concentration (pure water). (2)Molasses can enhance the moisturizing properties of coal dust. The moisturizing mass of the MDCD exponentially increased with an increase in molasses concentration, but the moisturizing rate was slightly influenced by the molasses concentration. (3)Molasses has a significant agglutination effect on coal dust. The bonding pressure of molasses solution on coal dust exponentially increases with the increasing of molasses concentration, and the maximum pressure of the coal dust block bonding by 40% molasses solution reached 171.21 N, which is 148.9 times that of the coal dust block bonding by pure water. (4)Molasses can effectively decrease the surface tension of a solution and increase its viscosity. At 40% concentration, the surface tension of the molasses solution reached 41.37 mN/m and the viscosity increased to 6.79 mPa·s. (5)Molasses can significantly suppress the wind erosion of deposited coal dust. The wind erosion mass of the deposited coal dust exponentially decreased with an increase in molasses concentration, and the wind erosion mass decreased by 99.1% at 40% concentration than that at 0% concentration (pure water).(6)The use of molasses to create a coal dust suppressant is highly feasible. However, the wettability of molasses solutions should be improved, and the viscosity of molasses solutions should be considered when developing molasses-based coal dust suppressants. The objective of this study was to investigate the suppression performance and mechanism of molasses solutions on coal dust at various concentrations. To achieve this objective, the moisturizing and agglutination of molasses on coal dust was tested, the physical properties of molasses solutions with different concentrations were measured, and the dust suppression efficiency of molasses on the deposited coal dust was investigated. Based on the above experiments, the suppression mechanism of molasses on coal dust is discussed, and the advantages and disadvantages of molasses in facilitating the creation of coal dust suppressants are analyzed. The following conclusions can be drawn:


Herein, a polycarbonate (PC) polymer is melt extruded together with titanium carbide (TiC) nano powder for the development of advanced nanocomposite materials in material extrusion (MEX) 3D printing. Raw material for the 3D printing process was prepared in filament form with a thermomechanical extrusion process and specimens were built to be tested according to international standards. A thorough mechanical characterization testing course  was conducted on the 3D printed specimens. The effect of the ceramic filler loading was also investigated. The nanocomposites’ thermal and stoichiometric properties were investigated with thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), energy-dispersive X-ray spectroscopy (EDS), and Raman respectively. The specimens’ 3D printing morphology, quality, and fracture mechanism were investigated with atomic force microscopy (AFM) and scanning electron microscopy (SEM) respectively. The results depicted that the addition of the filler decidedly enhances the mechanical response of the virgin polymer, without compromising properties such as its processability or its thermal stability. The highest improvement of 41.9% was reported for the 2 wt.% filler loading, making the nanocomposite suitable for applications requiring a high mechanical response in 3D printing, in which the matrix material cannot meet the design requirements. Additive manufacturing (AM), in which the 3D printing process belongs, is a technology with high potential for use as a manufacturing process, competing with conventional processes, with which nowadays they can be integrated . Among iPolycarbonate (PC) is a thermoplastic polymer used in several engineering applications, such as automotive, data storage, and construction, among others . Due to Metal carbides as additives induce advanced properties to the composites, hence they are popular materials used in various types of industrial applications, such as biomedical applications , energy In this work, for the first time, TiC was used as a filler for the reinforcement of the PC polymer in material extrusion 3D printing. The aim was to produce nanocomposites with enhanced mechanical properties from popular materials in industrial applications. The improved mechanical properties result in decreased parts segments, reduced weight, and material consumption, while, at the same time, exploiting the advantages and characteristics of 3D printing and expanding its use in more advanced industrial areas. Nanocomposites were prepared at various concentrations and tested with tensile, flexural, impact, microhardness, and dynamic mechanical analysis (DMA), according to international standards, to fully characterize their mechanical response. The effect of the filler loading was also investigated. Additionally, the nanocomposites were evaluated for their thermal and spectroscopic behavior and scanning electron microscopy (SEM) was employed for the investigation of the fracture mechanism in the fabricated specimens, while atomic force microscopy (AFM) evaluated the surface quality of the produced filament. In all cases studied, the filler had a positive effect on the mechanical response of the nanocomposites when compared to the pure matrix material, showing the potential of the studied nanocomposites for use in applications requiring an advanced mechanical response. The highest improvement of an enormous 41.9% was recorded in the tensile strength of 2 wt.% filler loading, which had overall the most enhanced performance.In 3, tensile stress at fracture 70.0 MPa, and elongation at fracture 110%. Titanium carbide (TiC) was procured from Nanographi  in nanopowder/nanoparticles form. The purity of the powder was 99.5+%, the size of the nanoparticles was (NPs) 33–55 nm, they had cubic shape, their true density was 4.5 gr/cm3, and their melting point was 3200 °C.The matrix material of this work was procured in pellet form from Styron Europe GmbH . The matrix material was PC polymer under the commercial name EMERGE (PC) 8430-15, produced by Trinseo S.A. . The PC grade, according to its technical datasheet, had a density of 1.20 g/cmFirst, materials  were dried in a laboratory oven (60 °C for 24 h) to remove any humidity from them. Then, the materials were mixed at four different filler loadings, i.e., 1.0 wt.%, 2.0 wt.%, 3.0 wt.%, and 6.0 wt.%. The mixture process was implemented in a glove box to restrain the spread of the powder in the room with a high-power blender. Each mixture was further dried, and then it was fed in a Noztek  single screw extruder. The produced filament was shredded to pellets in a 3devo  shredder. The pellets were then fed in a 3devo Composer  single screw extruder for 3D printing 1.75 mm diameter filament production. This extruder was equipped with a screw , with a special design for materials and additives mixing, according to the manufacturer, and it had four independent heating zones for better temperature adjustment in the extruder chamber. Temperatures were adjusted to each heating zone based on experiments conducted prior to the production of the filament of this work, and they were as follows: heating zones 1–3 (1 is closer to the nozzle) 200 °C, heat zone 4 240 °C. This process with the two extruders was followed to achieve as good dispersion of the filler in the polymer matrix as possible. Filament, which was the raw material for the 3D printing process that followed, was produced for each nanocomposite studied herein with this process. Filament with the pure PC material was also produced for the manufacturing of 3D printing specimens for comparison purposes.As mentioned above, the produced filament was the raw material for the manufacturing of the 3D printed specimens, which was implemented in an Intamsys Funmat HT  material extrusion 3D printer. The 3D printing parameters used were the same in all cases, and they were experimentally determined to ensure the processability of the materials before 3D printing the specimens that were tested in this work. The 3D printing parameters used are shown in Before the mechanical characterization of the prepared nanocomposites, their thermal and spectroscopic properties were investigated to determine characteristic parameters and to evaluate the stability of the nanocomposites. The thermal behavior of the nanocomposites was investigated with thermogravimetric analysis , while the spectroscopic investigation was conducted with Raman spectroscopy. TGA also verified that the temperatures used for the filament and the specimens’ production during the extrusion processes in this work did not compromise the thermal stability of the materials. The parameters for each test are shown in The quality of the produced filament was examined before the 3D printing of the specimens with it. During the filament extrusion process, the produced filament diameter was recorded by the 3devo Composer  extruder, and the produced graphs were inspected to ensure that the diameter was within acceptable deviation for the 3D printing process. Additionally, filament diameter was measured in random positions with a high-quality caliper. The strength of the filament was measured with tensile tests to evaluate its mechanical strength and provide quantitative information regarding the effect of the 3D printing process on the nanocomposites. Tests were conducted on an Imada MX2  tensile test apparatus, with custom-made grips for the fixture of filament in the machine for the tests. Finally, the surface roughness of the produced filament was measured with atomic force microscopy (AFM) on a MicroscopeSolver P47H Pro , and the resonant frequency was of 300 kHz. These measurements provided an indication of the filament extrusion quality, and the effect of the filler loading on the filament quality could be evaluated.For the evaluation of the mechanical performance of the produced nanocomposites in material extrusion 3D printing, as mentioned above, specimens were manufactured to be tested with various mechanical tests according to international standards. The tests conducted are presented in For the morphological characterization of the specimens, scanning electron microscopy (SEM) was employed. A JEOL JSM 6362LV  apparatus was used. Images were taken in high-vacuum mode (20 kV) at different magnification levels on the side surface of tensile specimens to evaluate the 3D printing quality in all filler loadings. The fracture mechanism on the tensile specimens was evaluated by taking images from the corresponding fracture surface of tensile test specimens from all materials prepared and tested in this work. In all cases, specimens were gold coated to avoid charging effects. Energy dispersive X-ray analysis (EDX) was also employed in the same apparatus to verify the basic elements in the nanocomposites. In this case, un-sputtered specimens were used.−1 and up to 3073 cm−1 (073 cm−1 . Based o3) values and their deviation calculated in the tensile and the flexural tests, respectively. Toughness is a value calculated as an integral of the stress-strain graph and provides an indication of the absorbed energy of the material during the tests. As it is shown, the addition of the filler increased the toughness in the tensile tests in all cases studied, with the highest value calculated in the 2 wt.% loading nanocomposite, which showed a 55.7% increase when compared to the pure PC material. The flexural toughness results followed the trend of the flexural test results, exhibiting the highest flexural toughness value at the 3 wt.% loading nanocomposite, with an increase of 14.6% when compared to the pure PC material.PC/TiC nanocomposites were prepared in this work for MEX 3D printing, and various tests were conducted for the mechanical characterization of the prepared materials. For loadings up to 3 wt.%, the addition of the filler had a positive impact on the mechanical response of the material compared to the pure PC polymer, with the 2 wt.% exhibiting the highest values in the tensile tests and an enormous 41.9% improvement compared to the matrix material, and the 3 wt.% had the highest values in the flexural tests, with 11.7% compared to the matrix material. In the highest filler loading studied of 6 wt.%, the mechanical performance of the material decreased, showing that this loading is plausibly approaching (but not reaching) a saturation threshold for the TiC filler in the PC polymer. The 6 wt.% is not the threshold, since at the tensile tests, the calculated value was still higher than the matrix material, but in most of the tests, the response of this specific loading was degraded compared to the rest of the materials studied. In the tensile tests of the 3D printed specimens, the pure PC exhibited lower tensile strength (53 MPa) than the nominal of the material, reported in its datasheet (60 MPa). Such differences are expected and can be attributed to the 3D printing process and differences in the experimental conditions. With the addition of the filler, the tensile strength of the nanocomposites reached the nominal tensile strength of the pure PC material and was higher than the pure material in the case of 2 wt.%, showing that the nanocomposites prepared in the work can exploit the advantages of 3D printing in applications requiring advanced mechanical performance. In literature, there is no similar study with PC material and TiC in AM or any other type of manufacturing process since this filler is mainly used as a reinforcement in metals, so the results of the study cannot be evaluated with literature. In metals, the reported reinforcement is similar to the results of this study .For the mechanical characterization of the nanocomposites developed in this work, specimens were 3D printed with a MEX process, so the effect of 3D printing in the nanocomposites was also considered, along with the effect of the filler loading. For the 3D printing of the specimens, the filament was fabricated with a thermomechanical extrusion process from raw materials (polymer and TiC nanoparticles) in powder form. The filament was also tested in the tensile experiment to qualitatively evaluate the effect of the 3D printing process on the material. The results followed the same trend as the tests on the 3D printed specimens, with an enhancement in the tensile strength in all loadings tested when compared to the matrix material. Still, results cannot be directly compared to the tensile tests on the 3D printed specimens, since the tensile tests on the filament were not following a standard.In all cases studied, the thermal stability of the matrix material was not affected by the addition of the filler, while the temperatures used for the filament extrusion and the manufacturing of the specimens were not close to the degradation temperatures of the matrix material and the nanocomposites. EDS confirmed the elements in the nanocomposites, while the SEM images revealed a very good 3D printing quality and a rather brittle fracture mechanism in most cases in the tensile tests. One critical parameter in the preparation of nanocomposites is the dispersion of the filler in the matrix material, to form a proper NPs network. In this work, a two-step process was followed to achieve as good a dispersion as possible, while agglomerations were observed mainly in the 6 wt.% loading nanocomposite in the SEM images. Additionally, in all tests conducted, the deviation between the results was within acceptable limits, with the filler significantly reinforcing the PC polymer, which is an indication of a well-distributed NPs network, as a result of a good dispersion of the filler in the matrix.−1), the C-H out-of-plane bending (700 cm−1), ν[O-(C=O)-O], ν(C-CH3), r(CH3), ν(ring) (883 cm−1), and the C-O-C stretching . There was a gradual increase versus concentration in the CH2vAS or C-H (2912 cm−1) and the C-H stretching (3071 cm−1). Furthermore, two new Raman peaks were identified in the Phenyl ring vibration (647 cm−1) and the C=O vibration (1740 cm−1). Lastly, the peaks of CH2vAS/C-H and CH/CH2 stretch modes remained constant. The described peaks are also shown in the following The comparison of the samples with the PC-clear showed that Raman peaks have the following changes. An increase in the PC-TiC samples is presented in the phenyl ring vibration , but the effect in the overall cost of the process is low. Additionally, such costs can be considerably decreased for industrial-scale use. As future work, different carbides can be used as fillers in the PC polymer, and additional properties of the prepared nanocomposites can be investigated based on the properties of the filler, which are induced in the matrix in the nanocomposites.