A small mass transport of Ca and Mg into the metal phase was also observed, which was shown to be affected by the slag chemistry. The obtained results indicated that the valorization of both Al dross and FeMn slag in a single process for the production of Mn, Mn-Al, and Mn-Al-Si alloys is possible. Moreover, the energy balance for the process indicated that the energy consumption of the process to produce Mn-Al alloys via the proposed process is insignificant due to the highly exothermic reactions at high temperatures.The aluminothermic reduction process of manganese oxide from different slags by aluminum was investigated using pure Al and two types of industrial Al dross. Two types of MnO-containing slags were used: a synthetic highly pure CaO-MnO slag and an industrial high carbon ferromanganese slag. Mixtures of Al and slag with more Al than the stoichiometry were heated and interacted in an induction furnace up to 1873 K, yielding molten metal and slag products. The characterization of the produced metal and slag phases indicated that the complete reduction of MnO occurs via the aluminothermic process. Moreover, as the Al content in the charge was high, it also completely reduced SiO Aluminum is the most abundant metallic elements in the Earth’s crust, posing an excellent combination of chemical, mechanical, and physical properties which makes it suitable for many applications . Aluminu2O3, and SiO2 [Manganese is ranked as the 12th most abundant element in the Earth’s crust, is applied in the steel and aluminum industry, and in its elemental and alloy forms is used as an alloying element. The massive production of manganese is via the carbothermic reduction of Mn ores in submerged arc furnaces, which yields Mn ferroalloys such as high-carbon ferromanganese (HCFeMn) and silicomanganese, SiMn . In 2019and SiO2 . If HCFe2O3 particles obtained from the cathodes of discharged alkaline batteries. The authors have proven that the magnesium content of the base alloy is a very important factor in the aluminothermic reduction, since this element improves the wettability of aluminum on the Mn2O3 particles, which in turn supports solid/liquid reaction. Kavitha and McDermid [2O3 reaction product was relatively constant (3–4 nm) for all the reaction times investigated. Jiaxing et al. [2 by metallic Al particles through a thermite process, and studied the conversion of MnO2 to Mn2O3 and Mn3O4 using Differential Scanning Calorimetry (DSC) techniques. They have provided information about the heat generation due to the reactions at temperatures below 900 °C, but they have not produced metallic manganese in their experiments. Sarangi et al. [2 and Al powders using the Differential Thermal Analysis (DTA) technique and determined the heat generation due to aluminothermic reduction reactions, varying the MnO2/Al ratio. Based on the rate of heat generation in DTA experiments, they calculated the rate of the reduction reaction and further performed a kinetic study. Bhoi et al. [2 or manganese ore were applied as the manganese oxide source [A literature survey ,22,23,24McDermid  have invAs is mentioned above, the present work is focused on the high-temperature aluminothermic reduction process of MnO from synthetic and industrial HCFeMn slags by pure Al and two industrial AWDs. The main chemical reaction of the process at elevated temperatures can be written as:Obviously, the highly exothermic nature of this reaction is beneficial regarding the overall process energy consumption. Moreover, thermodynamic software (FactSage ver. 7.3.) is used to discuss the results and find the mass and energy balances.The materials preparation and applied methodology are described as follows.Two aluminum dross samples were collected from skimmed dross over the surface of molten primary Al and an Al-Si-Mn alloy . In order to directly extract a representative Al dross sample from the surface of the molten alloy, a special sampling tool was designed and developed. Initially, the sampling tool was introduced into a dross tub, and when the Al dross was skimmed from the reverberatory furnace into the tub in which the tool was positioned in, a portion of the hot dross was collected from the surface of the molten alloy by the sampling unit. The thickness of the dross layer collected for testing was in the range of 20–30 cm. The dross 1 (from the primary Al) was used in its original form, and the dross 2  was subjected to a mechanical ball milling at room temperature to separate the fine oxide and the inclusion of the dross and to obtain rich metallic Al-containing particles. After the mechanical treatment, the milled dross 2 was partitioned by sieving and a particle size of 1.25–2 mm was further used. The microstructures and characteristics of these dross samples were studied by the Zeiss Ultra 55 Scanning Electron Microscope , coupled with energy-dispersive X-ray spectroscopy (EDS) and X-Ray Diffraction (XRD) . The synthetic slag was made by mixing pure CaO and MnO (above 99% purity level) oxides, and then melting in a top open induction furnace at 1873 K in a graphite crucible to obtain a CaO 25 wt.%. Pure Al and the dross 1 particles (1–10 mm) were mixed with the synthetic slag. The dross 2 (1.25–2 mm) was mixed with the HCFeMn slag, whereas CaO was in addition added with masses of about 10% and 25%. The addition of Al reductants to reduce the synthetic slag was required two times for the reduction of all MnO in the slag, and the utilized mass of dross 1 was approximated 69 g, as it contains a significant amount of AlThe crucibles with the charge mixtures were put in an induction furnace and a thermocouple was put into the charge mixture to measure the temperature inside the crucible. Each crucible was heated at about a 293 K/min rate up to 1773 K and held for 30 min in a protective atmosphere (flow gas Ar 5.0 at a constant pressure of 1030 mbar). The temperature recordings indicated the reaction kinetics, and it was observed that, upon reaching the target temperature (1773 K) for a few minutes, the temperature in the crucible was rapidly increased to a maximum in the range of 1973–2073 K, indicating that an aluminothermic reaction (1) was rapidly taking place. After that, the temperature inside the crucible declined to the target temperature. Then, the furnace power was turned off and consequently the molten components solidified. The metal is much heavier than the slag and it sinks in the crucible, as schematically illustrated in The produced metal and slag were separated after breaking the crucibles, and metallography samples were produced from them via mounting in epoxy resin followed by grinding and metallographic polishing. The structure and chemical composition were characterized using a Zeiss Ultra 55 SEM coupled with EDS.The obtained results for the materials and products are presented and discussed as follows.2O3, AlN, and SiO2, and the rest is metallic Al and Si. Hence, in the utilized 1.25–2 mm particles, we may have the same compounds but in a smaller total amount of about 18%, as approximated by image analysis. Hence, the metallic portion of these particles is about 80%. The SEM microstructural study of dross 1 indicated that almost 2/3 of the material was metallic and the rest was aluminum oxide, and this was the basis for using more mass of dross 1 in experiment 2 compared to experiment 1 , and it was found that small amounts of metal exist in the slag in the form of tiny solidified metal droplets, as illustrated in 2O3 phase diagram, the slag contains a fine structure of 3Ca·Al2O3 and 12CaO·12Al2O3 phases.The small amount of oxygen can be due to the surface oxidation of the metal phase during the sample preparation, and smaller amount may be in the form of dissolved oxygen in the alloy. Regarding the binary Mn-Al phase diagram  and the 2O3 through the reaction in Equation (1), and its further reaction with the adjacent CaO. Accordingly, metallic Mn is produced, and if there is excess aluminum for Mn oxide reduction it yields a Mn-Al alloy.The equilibrium in the interacting system at the process temperature was studied by the FactSage thermodynamic software, version 7.3., using the FACT Oxid and FACT Lite databases ,29,30,31The microstructural characterization evaluation is in good agreement with the equilibrium calculations by FactSage  that sho2O3 and CaO·6Al2O3 phases and a small amount of Al2O3 phases, which is expected regarding the binary CaO-Al2O3 slag system, and it having a higher amount of Al2O3 in the system compared with exp. 1. Similar to exp. 1, in exp. 2 Mn-free calcium aluminate slag was produced again, indicating the complete conversion of MnO to metallic Mn. It is worth mentioning that we did not observe the dissolution/degradation of the alumina crucible, as the molten slag is enriched rapidly by Al2O3 and the retention time is short.The obtained metal in exp. 2 is richer in Mn compared to exp. 1, and this is due to the lower amount of metallic reactant in the utilized dross 1 than in our estimated metallic Al above, yielding less Al in the produced Mn metal. It is worth mentioning that investigating the slag phase indicated that there was no unreacted metallic Al left, showing the formation of completely molten phases at elevated temperatures, complete chemical reactions (1), and proper phase separation. The SEM study of the slag in exp. 2 indicated again a calcium-aluminate slag that contained significant amounts of CaO·2AlThe results for the interaction of Al dross with HCFeMn slag indicated that in both exps. 3 and 4 we obtain two separable metal and slag phases, as seen in 2 and MgO. This indicates that almost all the SiO2 in the FeMn slag  and (5).Comparing the compositions of Ca and Mg in the produced slags 3 and 4 indicates that more Ca has been transferred into the metal phase with increasing CaO in the charge. Meanwhile, the Mg in the metal phase has been decreased. This can be evaluated with regard to the slag thermochemistry and the effect of the CaO addition on the slag. When adding more CaO, as in exp. 4, this causes the increased chemical activity of the CaO in the slag and enhances the kinetics of reaction (4), yielding a metallic product with a higher Ca content. On the other hand, more CaO in the slag reduces the chemical activity of MgO due to the decreasing MgO concentration, which consequently decreases the MgO chemical activity. Hence, the extent of chemical reaction (5) is reduced and less Mg is transferred into the metal phase.The provided information in 2O3 and CaO·2Al2O3, with an overall chemical composition of 24 wt.% CaO-76 wt.% Al2O3. The slag 4 was found to consist of CaO·Al2O3 and 12CaO·7Al2O3 phases. Obviously, the addition of more lime has affected the characteristics of the produced slags and the form of the calcium-aluminate phases, as expected with regard to the CaO·Al2O3 binary phase diagram.The SEM/EDS analysis of the produced slags 3 and 4 indicated that they are calcium aluminate slags with minor impurities. It was found that slag 3 consists of two main phases of CaO·AlAs was previously mentioned, the produced metal has a low concentration of C, as shown in in 2 in the ferromanganese slag and also the amount of it. Meanwhile, it was indicated that there was a complete recovery of Mn and Si from the ferromanganese slag. Considering the results of this work and introducing a method for the aluminum dross and ferromanganese slag valorization, the process is shortly evaluated as follows.The present experimental work indicates that it is possible to use a portion of the added metallic Al (pure or in dross) to conduct the aluminothermic reduction, and the rest of the Al is distributed in the metallic product. Hence, Al recovery depends on the MnO and SiO2O3 and CaO can be used easily in different industries, such as the cement, steelmaking, and aluminum industry, to recover alumina [2O3 slag. Moreover, an upgraded Al dross, high in Al, was utilized to reduce industrial ferromanganese slag, and Mn-Al-Si alloys were obtained.The change of reactant materials from pure  to real industrial  materials indicates that it is possible to have a complete aluminothermic reduction process in both cases. Moreover, as a result of the reaction a complete manganese oxide reduction to metallic manganese was achieved in both cases, as illustrated in  alumina . In the 3 (considering insignificant volume changes due to mixing), which is larger than the measured densities of calcium aluminate slags, that are in the range of 2.5–2.8 kg/cm3 at 1600 °C [The applied process in this research is very flexible for recycling Al scrap, Al dross, etc., and producing valuable Mn and Mn-Al alloys. Obviously, the thermochemistry of the slag and metal system at elevated temperatures is very important, affecting the quality of the process products. In order to fully separate the reduced metal from the remaining slag, it is emphasized that the observed lab results are validated at a large scale. like the current ferromanganese process in which molten metal and slag are well separated due to their large density differences. A molten metal with 41%Al-32%Mn-22%Si-3%Fe and 2%Ca  and the amount of Al in the alloy varies. The calculations were completed using HSC Chemistry software version 7 for two cases—i.e., case 1, where all reactants are heated to the process temperature, and the heat generated by the reaction causes the temperature to rise in the reactor. For case 2, the enthalpy of the exothermic reaction (1) is completely utilized to heat up the charge as well. In case 2, it can be assumed that small amounts of the reactants are initially interact and then the rest of the charge is added so that the heat generated by the reactions is mostly utilized to heat up the more added cold charge to the reaction temperature. The latter case 2 is of course technology-dependent, and can be implemented in different ways in practice, which is beyond this study.The process energy consumption for the presented aluminothermic reduction is mainly for heating the reactant materials to the high temperatures for the chemical reaction (1) to proceed. When the reaction is started, it is self-propagating and will continue until process completion. Hence, depending on the added reactants, the composition of the produced metal varies, as outlined above. The process energy consumption is, hence, very dependent on the characteristics of the reactants and their amounts. As the Al dross is a complex material that contains metallic Al and non-metallic components such as AlAccording to The aluminothermic reduction of MnO-containing slags was studied through using pure Al and two types of white Al dross, and the following results were obtained.Pure Mn-Al alloys were obtained via the aluminothermic reduction of highly pure synthetic CaO-MnO slag by pure Al, and with Al dross from the primary Al production process.The composition of the Mn-Al metal and the corresponding slag depends on the charge compositions and amounts.Mn-Al-Si alloys were produced using upgraded industrial Al dross and industrial ferromanganese slag, and the metal composition is slightly dependent on additional flux (lime) addition. More Ca is transferred to the metal when the CaO content of slag is increased.The composition and microstructure of the produced slag are very dependent on the charge mixture and can be easily engineered.The outlined process is very flexible, and a variety of charge mixtures can be used.The energy consumption of the process is low and is slightly affected by the target metal composition and the applied technology in practice regarding the energy savings.


Transmission electron microscopy is used to observe the morphological changes in colloidal gold nanoparticles and aggregation behavior of CS2 added to the colloidal gold nanoparticles’ solution. Raman spectroscopic analysis is further used to characterize the peaks of CS2, Cad and CS2-Cad molecules. Absorption spectroscopy is used to estimate the colorimetric differences and diffuse reflectance spectra of the samples. The sensing analysis is performed systematically in the presence and absence of CS2. CS2 added colloidal gold nanoparticles colorimetric sensor detected the BAs with a limit of detection (LOD) value of 50.00 µM. Furthermore, the developed sensor has shown an LOD of 50.00 µM for the detection of multiple BAs at a single time. The observed differences in the colorimetric and absorption signals indicate that the structure of BAs is converted to the dithiocarbamate (DTC)-BA molecule, due to the chemical reactions between the amine groups of BAs and CS2. Significantly, the developed colorimetric sensor offers distinct features such as facile fabrication approach, on-site sensing strategy, rapid analysis, visual detection, cost-effective, possibility of mass production, availability to detect multiple BAs at a single time and appreciable sensitivity. The developed sensor can be effectively used as a promising and alternative on-site tool for the estimation of BAs.Meat is often wasted due to the perceived concerns of its shelf life and preservation. Specifically, in meat formation, biogenic amines (BAs) are the major agents to spoil them. Herein, we have developed a carbon disulfide (CS All these substances are released from the amino acids (AAs), as they are disassembled from the proteins present inside the foods [Over the past few years, consumption of high-quality meat and meat products has been increasing steeply on a large scale ,2. Howevmmonia NH and biogethane CH, sulfurohe foods ,6. Amonghe foods . Principhe foods ,9.A low concentration of BAs produced from various types of food is essential to take action on gastric acid output and thermoregulation of the body; on the other hand, a high concentration of BAs is toxic to the body, which causes food poisoning or converts them to strong carcinogens . EspeciaCurrently, analysis of BAs in various food products is performed through various conventional instruments, such as high-performance liquid chromatography (HPLC), gas chromatography (GC) and capillary electrophoresis. These instruments can potentially measure BAs qualitatively and quantitatively with very high sensitivity and selectivity, but the price of the measurements is very expensive, and professional skills are required for the analysis, in which these instruments demand long-time consumption from the extraction, preprocessing and analysis ,15,16,17Another strategic method for the detection of BAs is surface plasmon resonance (SPR), which utilizes the charge density oscillation effect that occurred on the surface of the thin metal film. Chemical and physical changes that occurred on the fixed samples of the thin metal film can be measured through the resonance angle or the reflectance produced by the reducing reflexibility. Moreover, surface plasma wave conversion can happen during the absorption of light energy on the surface of the thin metal film ,21,22. BFrom these inferences, we can ascertain that traditional BA sensing techniques are time-consuming, and they are not suitable for the rapid and on-site detection of BAs. Thus, rapid, precise, accurate, consumer-friendly, cost-effective and on-site detection of the food quality is of utmost necessity for the safety and wellbeing of mankind globally. Over the past few years, significant attention has been made to maintain the quality and freshness of meat by developing novel detection techniques. Among the various types of sensing strategies, colorimetric sensing has been designated as a potential strategy for the efficient detection of BAs in meat and meat products.In this regard, colorimetric sensors based on the localized surface plasmon resonance (LSPR) effect of colloidal golds are developed, and various types of BAs are further determined. Colloidal golds were synthesized through a reduction reaction of gold ions with citric acids as stabilizers, and the detection of BAs was possible with particle aggregation effects. Combination possibility between different types of separate BAs and colloidal gold was determined and reactivity between a mixture of BAs and colloidal gold was further confirmed. Therefore, plasma absorption-based colorimetric sensors are expected as next generation sensors in food nutrition fields to effectively detect various types of BAs under different conditions.4∙3H2O; ≥99.9%), carbon disulfide , cadaverine , 1.4-diaminobutane (putrescine (Put); C4H12N2, ≥99.9%), histamine , tyramine , L-Histidine , L-lysine , L-Arginine  and L-Glutamine  were purchased from Sigma-Aldrich Chemicals, USA. Trisodium citrate dihydrate  was purchased from Kanto chemicals, Japan. Ultrapure water with a resistivity of 18.2 MΩ.cm was used for all the experimental procures and analysis.Gold (III) chloride trihydrate -Cad. To interpret the interactions and for the functionalization of CS2 and colloidal gold solution, CS2 was initially diluted with double the concentration of the target molecule. Further, 500.0 µL of the diluted solution was mixed with an equal amount of colloidal gold with an optical density value of 1, then the colloidal mixture was stirred for 10 min, this functionalization resulted in the fabrication of colloidal gold nanoparticles-based colorimetric sensor.Considering the molar ratio of the particles, CS2. BA samples viz Cad, Put, Him and Trm were prepared in three different types of mixture samples, in which sample 1 consists of Cad, Put and Trm, sample 2 consists of Cad, Put and Him, and sample 3 consists of Cad, Him and Trm. All these samples were prepared in the concentration range of 1.0 to 1000.0 µM. For the activation of the sensor, 500.0 µL of each sensing solution and the prepared BAs samples were mixed and kept under stirring for 10 min, later the absorbance spectrum of the samples was measured to ascertain the aggregation behavior of the colloidal gold.For the colorimetric sensing of BAs in distilled water, colloidal gold nanoparticles’ solution was mixed with and without CS−1. Colorimetric differences and UV-vis diffuse reflectance spectra of the samples were measured using ultraviolet-visible (UV-vis) spectrophotometer  in the range of 300–800 nm.Transmission electron microscopy  images were used to study the morphological changes in the colloidal gold solution. Raman spectroscopic analyses were performed using a Raman spectrometer  in the range of 300–2000 cm2 and colloidal gold nanoparticles was described in 2 mixture resulted in the occurring of interactions between the colloidal gold nanoparticles, CS2 and BAs. All these molecules, with their associated molecular interactions, lead to the aggregation of colloidal gold nanoparticle solution. Under the visible light, the colloidal gold solution itself emitted strong red light, due to the LSPR effect. Absorption spectra of colloidal gold particles showed a red shift due to the aggregation of the particles or the peak shift effect when the surrounding refraction rates of chemical or biological particles were attached to the surface of the gold particles [2 to the colloidal gold solution, characteristic changes were not observed in the color, representing that molecular interactions of the CS2 and the colloidal gold solution did not undergo any changes and both the molecules were properly mixed. Finally, with the addition of the selected BAs to the colloidal gold/CS2 colorimetric sensor, the color of the sensing solution has been changed to blue, which indicated the aggregation mechanism of the colloidal gold solution. 2 solution upon the addition of CS2 and BAs. The reactions occurring in the colorimetric sensor could be ascertained based on the binding groups of the BAs. CS2 could not directly interfere with the colloidal gold solution, whereas colloidal gold/CS2 solution interfered with each other with the help of an amine group of BAs, which further lead to the formation of DTC. Generally, the binding group of BAs change from the amine group to DTC through the reaction with CS2. To lead the aggregation of colloidal gold nanoparticles for colorimetric sensing of BAs, two DTC molecules are required as CS2 could not directly bind to the colloidal gold nanoparticles. With the formation of DTC, the length of the molecules is increased, and the molecular interaction changes from electrostatic interaction between carboxyl and amine group to chemisorption between DTC and surface of colloidal gold nanoparticles [2 and BAs were further analyzed through obtained TEM analysis. The TEM image of the colloidal gold/CS2 solution , UV-vis spectroscopy analysis was performed by adding various concentrations of CS2 to the DTC-Cad  value was found to be 25.00 µM regardless of CS2. The observed differences in the colorimetric and absorption signals indicated that the structure of Cad was converted to the DTC-Cad molecule due to the chemical reactions between the amine groups of Cad and CS2. The formation of DTC-Cad resulted in the increase of the length of molecules and molecular interaction changes of the Cad binding group.In the case of colorimetric detection analysis of Cad in the presence and absence of CS2, Put showed the active section of the solution concentration between 50.00 and 500.00 µM with the colorimetric signals ranging from 44.37 to 72.03, whereas in the presence of CS2, an active section of the solution concentration ranged from 50.00 to 1000.00 µM with colorimetric signals ranging from 19.94 to 44.47. The LOD value for both the colloidal gold solutions was almost equal to 50.00 µM regardless of CS2. The representative colorimetric detection result of Put was similar to the Cad results. These similar phenomenologically resulted Cad and Put could be ascertained based on their chemical structures, as both the Put and Cad possess similar chemical structures. Put efficiently converted to DTC-Put, leading to the binding group transition. The colorimetric signals of Put were decreased when compared to Cad, due to the difference in the molecular length.2 were found to be apparent and distinctive, and the observed changes can be observed from the 2, the LOD value was found to be 5.00 µM; in this solution activation section was not clear, which depicted the dramatic increase in the colorimetric signals and peaks from 1.00 and 5.00 µM. This type of phenomenon was due to the relationship between the structure of Him and the colorimetric reaction process. Precisely, in Him two amine groups were combined with the colloidal gold suspension and attached to the imidazole ring [2, the LOD was increased to 10.00 µM with the expansion in the activation sites from 10.00 to 1000.00 µM with the colorimetric signals in the range from 11.17 to 60.02, which is quite similar to Cad and Put. This could be ascertained based on steric hindrance and the influence of the imidazole ring [2 was coupled with the amine group of His, this process can be the reason for getting a similar type of reaction to Cad and Put.In the presence of Him, colorimetric changes of the colloidal gold solution in the presence and absence of CSole ring . These sole ring . As both2, and the obtained findings were displayed in 2, LOD was found to be 250.00 µM and the colorimetric signal was increased from 250.00 to 500.00 µM. Nevertheless, the signal values were increased exceptionally at the same LOD value with the existence of CS2, this type of tendency could be due to the possibility of rapid π-π interactions and due to the increase of polarization differences in the benzene ring along with the structural change of amines through the CS2.Finally, the detection analysis of Trm was performed in the presence and absence of CS2 for the detection of BAs were confirmed through the absorption spectra analysis, the obtained spectra findings were illustrated in Changes in the plasmon spectrum of colloidal gold nanoparticles-based colorimetric sensors in the presence and absence of CSThe content of BAs generated by the decomposition of meat was gradually increasing based on the degree of decay concept, but the composition of BAs in the decomposed meat was changing either by the meat or with the changes in the environmental distribution ,36. Ther2, Cad, Put and Trm sample set showed LOD of 50.00 µM with signals of 8.95, whereas in the presence of CS2, signals showed a huge difference of up to 35.17 at the same limit of detection value The fabrication of the sensor is very simple.(ii)The developed colorimetric sensor detected the BAs within 10 min.(iii)The developed sensor can be efficiently used for the on-site analysis of BAs.(iv)The colorimetric sensor can be easily manufactured on the laboratory scale.(v)Mass production of the colorimetric sensor will be highly possible at the industrial scale.(vi)Notably, the developed sensor detects the multiple BAs at a single time.Compared to recently published reports , the fab2-based colorimetric sensor will bring novel insights and advancements for the fabrication of colorimetric sensors to detect various types of food pathogens.The developed sensor will be useful to detect BAs in various types of foods, particularly to detect the freshness of meat and meat products. Further, we anticipate that the developed colloidal gold/CS


The roughened plastic optical fiber (POF) taper assembled PPy films  were facilely prepared and bent U shape structure for testing ethanol gas at room temperature. The morphologies of the PPy films and the roughened POF taper were studied using electron microscopy. The effect of the three PPy films on the gas response was investigated and the results showed that the POF-PPy2 exhibited a high sensitivity of 5.08 × 10−5 dB/ppm. The detection limit of the sensor was 140 ppm and its response and recovery times were 5 s and 8 s, respectively. The results also showed that as the bending radius decreased, the response and recovery times gradually shortened, while the output power increased. In addition, the proposed sensor has advantages of a low cost and simple structure.The three polypyrrole (PPy) films with different mixture ratios, namely PPy1, PPy2, and PPy3, were synthesized by chemical oxidation with pyrrole and ferric chloride (FeCl Due to the high numerical aperture (NA), proper curvature, and secure processing, plastic optical fibers (POFs) have attracted significant attention from researchers and have been widely used in different applications such as gas detection, biomedical, and other fields ,2,3,4. T3), ammonium sulfate, and ammonium persulfate were used as oxidants to prepare PPy films [3 and pyrrole. Their experimental results showed that when methanol was used as a solution, the conductivity of PPy was the highest. The ratio of FeCl3 to pyrrole of 2.33:1 is expressed as follows:The PPy has the advantages of simple preparation methods and high conductivity ,20. The Py films ,22,23. MPy films  studied 3 to pyrrole on the morphology and gas sensitivity of PPy films; the ratio of FeCl3 to pyrrole was set to 5:1, 5:2, 2:1, and 1:1, respectively. The results showed that the PPy film had the highest sensitivity to the volatile organic compounds (VOCs) when the ratio was 5:1. In this study, the effect of the reactant ratio greater than 5:1 on the thickness and gas sensitivity of PPy films was studied.Using the configuration ratio based on the Equation (1), Qin et al.  synthesi3 to pyrrole of 5:1; 15:2; and 10:1. The PPy films were modified on the surface of the POF polished with sandpaper to form three sensitive probes, namely, POF-PPy1, POF-PPy2, and POF-PPy3. The sensitivity at different bending radii was also analyzed at room temperature (RT). The experimental results showed that the POF-PPy2 had a fast response and high sensitivity. The response and recovery times were 5 s and 8 s, respectively, when the concentration of the ethanol gas was 140 ppm, and the sensitivity was 5.08 × 10−5 dB/ppm. When the bending radius was 3 cm and the concentration of the ethanol gas was 1400 ppm, the response and recovery times of the proposed sensor were 15 s and 17 s, respectively.The PPy films were prepared using chemical oxidation, with the substance ratio of FeClThe V-number  characterizes the number of propagation modes in optical fiber ,29 and iessed as :(3)Vt=2πThe properties of the PPy film vary when in contact with ethanol due to environmental conditions. The schematic diagram of the proposed sensor is shown in PPy film . On the n states . The dopn states . With thn states ,33.3  was stored in a sealed container. All of the used chemicals were analytical-grade reagents and they were used without the need for extra processing.The pyrrole  was stored in a brown bottle and protected from the light. The FeCl3 powders having the weight of 0.1443 g, 0.2164 g, and 0.2885 g were used. A pipette took three pyrrole resolutions of 12 μL. As shown in 3 powders, respectively, and they were stirred evenly in the beaker. The pyrrole solutions were disposed of in the same manner as the FeCl3 solutions. The three FeCl3 solutions and pyrrole solutions were poured into three glass-culture dishes with a diameter of 8 cm and left to react at room temperature for 4 h. The three black-gray PPy films were formed on the surface, as shown in The three FeClA POF  with a length of 30 cm was used, which had a core of 980 μm and a fluorinated-polymer cladding of 10 μm. It was polished using 2000 mesh sandpaper at a distance of 2 cm in the middle of the fiber. The electron microscope controlled the processing depth. The roughened POF taper was cleaned with deionized water. The parameters of the fiber are presented in The experimental setup is shown in It can be seen from The micrographs of the three PPy films  observed under the 5-μm scale are shown in −5 dB/ppm.In order to study the effect of three reactant concentrations on the gas sensitivity of the prepared PPy films, the response and recovery time of the ethanol gas in the range of 0–3500 ppm of the three sensitive probes were measured at room temperature (RT). The response and recovery time of the proposed sensor were considered as time passed until the responses reached 99% of their respective values. The change in power was determined by the input power and output power reaching the gas detection value. The response time, recovery time, and power variation of the three sensitive probes at different ethanol concentrations are presented in Comparison of the proposed sensor and the previously reported ones is presented in A cladding POF taper was prepared using the heat-and-pull technique with a smooth surface; the surface was modified with the PPy2 film. The processing parameters were chosen as shown in The material properties determine the repeatability of a sensor. In order to evaluate the repeatability of the proposed sensor, three sensitive probes  were tested. As shown in In addition, it can be seen from The effect of the bending radius on the gas sensitivity was also measured. The POF-PPy1 was selected and bent it into a U-shaped mold of 3 cm to 10 cm. The effect of the bending radius on the response and recovery times at the gas concentration of 1400 ppm is displayed in essed as :(4)d=λ2π3 . The size of the PPy film is of the micron-order so that it can support the transmission of the light. When the POF taper was in contact with the PPy film, the adhesion helped the PPy film to attach closely to the fiber surface and the friction force of the roughened POF prevents the movement of the PPy film on the surface of the fiber. The proposed sensor was verified experimentally, and it was also compared with the related sensors. The experimental results revealed that the proposed sensor had excellent repeatability and response to the ethanol. The sensitivity to the ethanol was the highest among all the tested sensors, and it was 5.08 × 10−5 dB/ppm at the ratio of FeCl3 to pyrrole of 15:2. With the decrease of the bending radius of the optical fiber, the response and recovery times were shortened and the output power was increased. The additional advantages of the proposed POF-PPy sensor are that it is easy to fabricate and is inexpensive. In our future work, the PPy films will be applied to the detection of other gases to evaluate the performance of the proposed sensor further.In this work, PPy films were successfully polymerized by the chemical oxide, while the pyrrole content was much less than that of the FeCl


This review summarizes recent advances of doped TiO2-based photocatalysts used in hydrogen production and the degradation of organic pollutants in water. An intense scientific and practical interest in these processes is aroused by the fact that they aim to solve global problems of energy conservation and ecology.The growth of industrialization, which is forced to use non-renewable energy sources, leads to an increase in environmental pollution. Therefore, it is necessary not only to reduce the use of fossil fuels to meet energy needs but also to replace it with cleaner fuels. Production of hydrogen by splitting water is considered one of the most promising ways to use solar energy. TiO At present, hydrogen is regarded as the fuel of the future. Compared to carbon fuel, hydrogen is considered a renewable and environmentally friendly source of energy. There are various methods for producing hydrogen on an industrial scale. However, all known methods are characterized by high energy consumption, which makes the process of hydrogen production on a large scale disadvantageous. The production of hydrogen by photocatalytic water splitting is technologically simple, and the outcoming gases are environmentally friendly.2 is a wide-bandgap semiconductor. In nature, TiO2 is usually found in three different crystalline structures: rutile, anatase, and brookite. TiO2 in anatase form is the most widespread photocatalyst for hydrogen evolution [2-based electrode demonstrated the ability to split water under the influence of ultraviolet radiation [2), which is not consumed during the entire process, water, sunlight or ultraviolet radiation. During the absorption of light (≥TiOvolution . Howeveradiation . Photocaion (2)) ,5.(1)Ti2-based photocatalysts is based on their ability to discolor and completely decompose organic dyes contained in water. In addition, there are a number of works in which TiO2-based photocatalysts were used to neutralize harmful to the atmosphere gases [2-based photocatalysts to solve the main global problems associated with pollution of the environment and need for renewable energy [2 as a photocatalyst is commercially produced in powder form. The most common brand of TiO2 based photocatalyst are P-25 Degussa/Evonik, TiO2 nanofibers from Kertak, TiO2 Millennium PC-500, TiO2 Hombikat UV-100, Sigma Aldrich TiO2, TiO2 PK-10, and P90 Aeroxide.Another important application of TiOre gases ,7,8,9. Ce energy ,11. Curr2 based photocatalysts with significant advances. In this review, attention is also paid to the study on the mechanism of photocatalytic processes, factors affecting the activity of photocatalysts, and new techniques used to increase the activity of TiO2 based photocatalysts during the splitting of water with the evolution of hydrogen and decomposition of organic compounds utilized for water purification.This paper aims to provide a brief overview of articles published starting from 2017 on new research and developments of TiO2. In the case of recombination of charge carriers in a sufficiently fast interval (<0.1 ns), the photocatalytic activity of the semiconductor is not observed. For example, the lifetime of electron-hole pairs of ~250 ns (TiO2) is considered relatively long [The activity of photocatalysts strongly depends on the lifetime of photogenerated electron-hole pairs. An important role is played by the rate at which charge carriers can reach the surface of the photocatalysts. The results of spectroscopic studies show that the time intervals between redox reactions or recombination involving charge carriers are extremely short, resulting in a significant reduction of the photocatalytic activity of TiOely long . Thus, i2 nanoparticles have, generally, a higher photocatalytic activity [2 photocatalyst microparticles, the penetration depth of UV rays is limited and amounts to about ~100 nm. This means that the inner part of the TiO2 photocatalyst microparticle remains in a passive state. [2. This is one of the reasons for the increased interest in nanosized particles of TiO2.Compared to microparticles, TiOactivity ,14. Thise state. . Figure 2 and control it in the process of its obtaining.As shown in 2 in the visible region of the spectrum, the spectral region of its absorption should be expanded. There are several approaches for sensitizing TiO2 to visible light: doping with cationic and anionic elements or metal nanoparticles. Elements of the 3d- and 2p-groups are often used as additives to reduce the value of the bandgap of the photocatalyst [To increase the photoactivity of TiOcatalyst ,18.2 at the position of Ti4+ ions. Rare-earth, noble, and transition metal cations can be used [2, increases the redox potential of the formed radicals, and increases quantum efficiency by reducing the degree of recombination of electrons and holes. The nature and concentration of the dopant change the charge distribution on the TiO2 surface and affects the process of photo corrosion and photocatalytic activity [2 structure, which can act as charge recombination centers, this leading to a decrease in photocatalytic activity even under the influence of UV light.The essence of cationic doping is the introduction of metal cations into the crystal structure of TiO be used . Doping activity . However2 depending on the nature of metal-based dopants. According to the results of the study, it is found that doping does not significantly change the bandgap of rutile, while in the case of doping anatase with iron and chromium, its bandgap narrows significantly. As a result of doping with metals, the photocatalytic activity of anatase (A) increases in the following order: A < A/Co < A/Cu < A/Fe. In the case of rutile (R), its photocatalytic activity decreases in the following order: R > R/Co > R/Cu > R/Fe > R/Cr. According to the authors, the decrease in the photoactivity of TiO2 may be associated with the inhibitory effect of impurity cations.In , Kryzhit2 samples doped with nonmetallic elements  in the anionic positions of TiO2, demonstrate high photoactivity in the UV and visible regions of the solar spectrum [2 (O2p), which reduces the bandgap and shifts the absorption spectrum. The inclusion of carbon in TiO2 can also lead to the formation of carbon compounds on the surface of the photocatalyst, which acts as absorption centers of visible radiation [Over the past few years, it has been shown that TiOspectrum ,23. Amonspectrum ,25,26. Tadiation .2. Introduction of nitrogen into the TiO2 structure contributes to a significant shift of the absorption spectrum into the visible region of the solar spectrum, a change in the refractive index, an increase in hardness, electrical conductivity, elastic modulus, and photocatalytic activity in regard to visible light [2 [g1 (TiO2) > Eg2 (N-doped TiO2), thus contributing to the absorption of photons of light with lower energy.Doping with nitrogen atoms is the most popular way to improve the photocatalytic performance of TiOle light ,29. Uponlight [2 . As show2 is fluorine atoms [− and 1.4 Å for O2−). The increase in photocatalytic activity is mainly associated with an improvement in the degree of crystallinity of TiO2 due to doping with fluorine [2 [2 in comparison with amorphous TiO2 has significantly fewer defects, which reduce the possibility of recombination processes and contributes to the efficient movement of photogenerated charge carriers in the semiconductor. Since redox reactions occur on the surface of TiO2, one of the main requirements for photocatalysts is the presence of a developed specific surface area. However, the presence of a developed specific surface area implies a large number of defects in the structure and a low degree of crystallinity and, as a result, reduces photocatalytic activity. Therefore, to increase photocatalytic activity, it is important to find a balance between the above factors.Doping with nitrogen in the oxygen position is difficult since the ionic radius of nitrogen (1.71 Å) is much larger than that for oxygen (1.4 Å). Another auspicious element in the anionic positions of TiOne atoms . Unlike fluorine . It has orine [2 ,34. The 2 [2 can lead to the movement of electrons from the TiO2 structure to metal particles deposited on its surface. This helps to avoid the recombination of charge carriers, since the holes remain in the valence band of TiO2. This is also beneficial for avoiding the recombination of charge carriers since the holes remain in the valence band of TiO2. A number of conducted investigations indicate that the properties of these photocatalysts depend on the dispersion of metal particles [2 and prevent the absorption of photons, leading to a decrease in the efficiency of the photocatalyst.The application of metal nanoparticles is another alternative approach to the modification of photocatalysts. A review of the recent literature shows that metals  significantly increase the photocatalytic activity of TiO2 ,36,37. Tarticles ,39. Enhaarticles . Despite2 based photocatalysts with various morphologies in the form of nanowires, nanospheres, nanorods, nanotubes, and nanosheets [2 nanocomposites with different structures, as well as their photocatalytic characteristics.Hydrogen can be produced by using nanoscale TiOnosheets . Table 12 microspheres with Au and Pt metals increases the hydrogen evolution twice. In the case of using Au, the maximum hydrogen evolution was determined at 1.5 wt.% content of Au in the sample with the yield of hydrogen 1118 µmol h−1, while for Pt its optimal content in the sample was 0.27 wt.% with the yield of hydrogen 2125 µmol h−1. The excess of dopants may result in decrease of photocatalyst activity due to possible complete coverage of TiO2 surface, thus, hindering the light to be absorbed. A literature review also showed that the difference in the optimal ratio for each metal could be associated with the formation of recombination centers on the semiconductor surface by metal particles [P. Melián et al.  demonstrarticles ,52.2 production was found when using sacrificial agents acting as electron donors (hole scavengers) during photoreforming, in which the hydroxyl radical is consumed by the sacrificial agents. In general, there are two types of sacrificial reagents: organic and inorganic based electron donors. Among organic electron donors, the most effective are water–alcohol mixtures, in particular, methanol > ethanol > ethylene glycol > glycerol [A positive effect on the rate of Hglycerol ,57,58,59glycerol  showed tglycerol . Neverthconsumed .2/CuO nanocomposites containing different amount of Cu. The color of the obtained samples, depending on the concentration of Cu-TiO2/CuO (CUT) from 1 to 4 mol%  changes from light green to dark green . Nevertheless, this type of photocatalyst is effective only for hydrogen production, since it has shown low efficiency in the decomposition of organic dye and metal detoxification in water.The amount of dopant also has a significant effect on the efficiency of light absorption by the photocatalyst and on its photocatalytic activity. For example, Udayabhanu et al.  preparedrk green . To eval2 and Au/TiO2) results in increase of the rate of hydrogen production. However, the hydrogen generation rate for Au/TiO2 photocatalyst at the same light intensity is 18–21 times higher than that for pure TiO2. The explanation to this is that Au can limit charge carriers’ recombinations and, what is more, the visible light absorption of photocatalyst is enhanced by the localized surface plasmon resonance effect of Au nanosized particles. The influence of the light intensity (from 1 to 9 kW/m2) and the duration of exposure on the rate of hydrogen generation for Au/TiO2 nanoparticles with a concentration of 1 g/L is also shown in The photocatalyst efficiency is affected not only by the nature of the alloying element but also by its concentration. For example, X. Xing et al. in  demonstr2/SrTiO3-TiO2 in the form of nanotubes using a two-stage hydrothermal process . The ob2 with a thermostable phase.In practice, photocatalytic reactions are mainly carried out at room temperature. It is found that increasing temperature has a positive effect on the activity of some photocatalysts, which makes it relevant to develop new photocatalysts based on the anatase form of TiO2, in the doped form, is used.Organic dyes are used on a large scale in modern industries. Wastewater polluted with such substances subsequently leads to environmental problems ,67. This2-based photocatalyst [2-based photocatalyst, electrons move into the graphene structure. Based on the author’s results [2/graphene-based photocatalyst can be obtained by creating either a chemical bond between them or via the approach of their mechanically mixing [Graphene has a large specific surface area and electrical conductivity. The presence of such properties in graphene is of interest to scientists in the preparation of a graphene/nano-TiOcatalyst ,72,73. A results , it helpy mixing ,76. Due 2/graphene attract scientists’ attention not only as highly efficient photocatalysts due to light absorption in a wide range and charge separation, but also taking in account its high adsorption capacity to pollutants. However, TiO2/graphene-based composite produced by the hydrothermal method cannot serve as an effective photocatalyst. The reason is the agglomeration of graphene layers, which adversely affects the adsorption and photocatalytic properties. The solution to this problem is described in [2 [2/graphene based photocatalysts to remove various organic compounds (pollutants and dyes) from water.Composites based on TiOribed in , where ged in [2 ,79. Aero2-reduced graphene oxide (rGO), and aerogel based on TiO2-rGO  on methyl orange. As shown in tructure .A significant role during photocatalysis is played by the surface microstructure, which influences the mass transfer of degradable organic compounds by the diffusion to the surface of the photocatalyst. It is important to take into account the fact that the fluid flowing over the surface with protrusions meets more resistance from the side of the walls, compared to the fluid flowing through the flat surface. As a result, such protrusions can adversely affect the degradation efficiency of organic pollutants.2 doped with Fe2O3 is one of the best-known effective photocatalysts. Due to the narrow bandgap of Fe2O3 (2.2 eV), its doping leads to a redshift of the light response of the photocatalyst. The phenomenon of decreasing of photoactivity of TiO2 based photocatalyst doped with non-metals during heating, the high cost of some metals and the availability of Fe2O3 in large quantities increases the attractiveness of Fe2O3 over other dopants [2O3 nanoparticles, which served as a doping agent for obtaining the TiO2/graphene aerogel (GA) based photocatalyst with a 3D structure  was purified to 97.7% .TiO dopants . J.-J. Z dopants  used Fe2tructure . Due to to 97.7%  b. Fe3O4atalysis . For exaatalysis  presente2 photocatalysts, in which a combination of UV radiation, hydrodynamic cavitation, and ultrasound was applied. In another work, the use of N and Cu-doped TiO2@CNTs in sono-photocatalysis for purification of pharmaceutical wastewater is discussed [To increase the efficiency of the process of degradation of organic pollutants by photocatalysis, attempts have been made to combine radiation with ultrasonic cavitation. S. Rajoriya et al.  reportediscussed . The resThe great interest in the use of ultrasonic action during photocatalysis is justified by the enhancement of electronic excitations, which leads to an increase in the density of pairs of charged particles. Under the influence of ultrasound, the aggregate photocatalysts are dispersed, contributing to the rapid renewal and expansion of the boundaries of heterogeneous reactions, which improves the mass transfer and the course of chemical reactions ,97.2-based photocatalysts was collected and analyzed. The efficiency of TiO2 doping by various components, which significantly increases the photocatalytic activity, is shown. In addition, other factors, such as the bandgap, charge carrier recombination, the use of sacrificial agents, the size and type of photocatalyst structures, surface morphology, photocatalyst concentration in solution, radiation source power, etc., which can affect the photocatalysis were analyzed. Despite the reports of scientists on the development of effective photocatalysts capable of operating under sunlight, their use is still not economically viable. Therefore, due to the growth of environmental problems and the limited availability of hydrocarbon fuels, investigations in the field of hydrogen production by “artificial photosynthesis” will undoubtedly increase.In this review, information on the main mechanisms of water splitting and decomposition of organic compounds by TiO


The proposed DMQAS could provide complete and accurate microenvironment data and can be used to further improve the quality and safety management of sweet cherries during express logistics.The market demand for fresh sweet cherries in China has experienced continuous growth due to its rich nutritional value and unique taste. Nonetheless, the characteristics of fruits, transportation conditions and uneven distribution pose a huge obstacle in keeping high quality, especially in express logistics. This paper proposes dynamic monitoring and quality assessment system (DMQAS) to reduce the quality loss of sweet cherries in express logistics. The DMQAS was tested and evaluated in three typical express logistics scenarios with “Meizao” sweet cherries. The results showed that DMQAS could monitor the changes of critical micro-environmental parameters (temperature, relative humidity, O In adonsumers ,4,5. Theonsumers ,7. Accor by 2025 .Although the sweet cherries industry is very popular in China, several factors are limiting its further development. Firstly, sweet cherries have high water content, short shelf life, and are extremely perishable and deteriorated with a limited shelf life of 7–10 days after picking ,10. SecoAs the development of the Internet economy and e-commerce platforms such as Alibaba, JD, and Pinduoduo, in 2018, more than 1.3 billion tons of fresh agricultural products were sold online in china . The “PrThe sweet cherries are delivered to the consumers through express logistics, which effectively alleviates the problems of uneven planting distribution and off-site sales. However, owing to lower profits, it is unrealistic to realize the full cold chain transportation for most sweet cherries . In addiExpress companies often focus on timeliness and efficiency, while ignoring the importance of quality monitoring and management during the express logistics. If the postharvest quality management of fresh in-transit sweet cherry cannot be controlled well, a huge quality loss would be caused, seriously reaching a 20%–30% rot rate and furthering causing economic loss ,11. The Sensory evaluation was used to analyze the quality of food , while t2, CO2, and C2H4 content) during express logistics. Besides, a freshness prediction model of sweet cherries was established based on back propagation (BP) neural network. Combined with quality parameters , pH, and chromatic aberration), this system could provide a theoretical reference for the timely decision-making and management of express logistics processes by freshness prediction, which could reduce the quality loss in the express logistics of sweet cherries.This study aims to reduce the quality loss of fresh sweet cherries in the express logistics. To accomplish such goal, a dynamic monitoring and quality assessment system (DMQAS) based on multi-sensors technology was proposed, thereby monitoring the key parameters of the microenvironment  and power loss, the lithium battery can guarantee that the monitoring terminal could work for enough time (at least 180 h), which can meet most of the current express transportation time demands.The monitoring platform was based on the STC12C5A60S2 chip shown in , which i2, CO2 and C2H4 in the sweet cherry transportation microenvironment, and converts the analog signals into digital signals for easy interaction with the control platform. According to actual investigation and review of literature, the gas composition involved in the sweet cherry transportation process is complicated, but the three gases of O2, CO2 and C2H4 have the greatest impact on the quality of sweet cherry. Literature shows that O2 and CO2 concentrations may stimulate or reduce the respiration rate of fruit cells, CO2 in the microenvironment does not directly inhibit the production of ethylene but may bind with some metal containing enzymes  in the sweet cherries fruits and affect the physiological indicators of the fruit. O2 is necessary for ethylene production, which may be inhibited at low O2 concentrations [2H4 plays an important role in fruit ripening and aging, and it has high response characteristics even for non-respiratory fruits such as sweet cherry. However, according to previous studies, there is only a low level of the Period I in the process of ripening and senescence of non-respiratory climacteric fruits such as sweet cherry [2H4 content in the sweet cherry transportation microenvironment is very low, which requires high precision and resolution for the C2H4 sensor.The sensing acquisition hardware is responsible for real-time monitoring of temperature, relative humidity, Otrations . Consequtrations . As a plt cherry . Therefo2 concentration, the maximum absolute error was 0.08%vol; the CO2 sensor was tested under five groups of different CO2 concentration, and the maximum absolute error was 0.0132%; the C2H4 sensor was tested under four groups of different C2H4 concentration, and the maximum absolute error was 1.01%. It can be seen from the static characteristics (2H4 sensor is the highest reaching 161.37 V/%vol when compared with an O2 sensor (0.067 V/%vol) and CO2 sensor (0.16 V/%vol), which means the ethylene sensor could monitor the small fluctuations of ethylene content in the microenvironment.The gas sensors were tested and calibrated respectively after assembled. Through pre-experiment, the sensors were tested to check the input and output characteristics, to determine whether the errors were within the allowable range and provide a reference for subsequent data analysis. The sensors are tested and calibrated with standard gas at laboratory temperature of 25 °C and relative humidity of 30%. Test point parameters are shown in eristics  that: thThe software of the Monitoring terminal was edited by Keil Uvison4 software, and the development language was C language. The main working flow of the software as shown in Step 1: Initialization. The first step of the main program is an initialization, including initializing the clock, Electrically Erasable Programmable read only memory (EEPROM), main function, etc., in order to ensure that each unit works properly.Step 2: Data acquisition. By performing an interrupt operation, the main program sends a signal acquisition command to each sensor node, and the interrupt program begins execution. Through the main control chip, each device node starts collecting micro-environment signals by received a high potential. If the signal acquisition is completed, it returns directly to the main program; if the signal acquisition fails, the loop statement is executed, and the acquisition is performed again until the complete signal is acquired.Step 3: Data reception. After each sensor node collects the signal, it returns to the data buffer (RAM) through the data bus serial port, and the counter increases by one, program execution judgment function, actively judge whether there is data in the buffer, if there is, ready to read and process one by one;STC chip control software is used to read data directly.Step 4: Reading the data. The program automatically reads the unprocessed data from the receive buffer and stores it in read-only memory (ROM). The read counter increments by one. After the data is stored in ROM, users or staff can use a personal computer or laptop to read the data in the storage chip. Data cable is used to connect the universal serial bus (USB) module of computer and single chip microcomputer, and Step 5: After the data was sent to RAM and stored in ROM, the sensor node begins to sleep and waits for the next collection instruction cycle sent by the main control chip.The goal of the freshness prediction model is to establish the coupling relationship between gas content and the quality of sweet cherries. Consequently, the quality of sweet cherries can be quantified, which is more specific and intuitive . Since tA BP neural network is neural network using an error backpropagation training algorithm. It has a multi-layer feedforward network with a hidden layer, which provided a higher prediction accuracy, adaptability, and robustness compared with the traditional linear model . The bas2, CO2 and C2H4) in the sweet cherry microenvironment are considered as the input, and the output layer is the freshness of the sweet cherry. The freshness prediction model is formed by connecting a plurality of neurons by certain rules, and mainly includes an input layer, implicit layers (intermediate layers), and an output layer. The number of neurons in the input layer is the same as the dimension of the input data. The three gas contents , “tansig” and “logsig” functions were selected as transfer functions, and “trainrp” functions were selected as training functions for the freshness prediction model. The maximum iteration number was set as 1000, the learning rate was set as 0.001, the accuracy was set as 0.001, and other parameters were set as default values. In this study, a total of 9000 gas experimental data of sweet cherry during transportation were divided into two parts according to the ratio of 7:2. The first part was used to train the model, and the second part was used to testing.The MATLAB R2016b math software  was used for modeling. The construction and training results of the freshness prediction model are shown in The experiment was conducted in Yantai city, Shandong province. The Yantai area is the main production region and distribution center for sweet cherries in China . The “MeImmediately following their harvest by manual or mechanical, the fruits were sorted and graded to remove fruit damaged by disease and insects, and then immediately transported to the laboratory. The experiment was mainly divided into three groups: ambient temperature group (Group I), ice-added group (Group II) and pre-cooling group (Group III), as shown in A total of 66 kg of sweet cherries of the same size and maturity (90% maturity) were selected and divided into three groups: I, II, and III. For each group, the sweet cherries was divided into 11 independent portions, in which ten portions were used for the quality test while the eleventh portion was used for monitoring the critical micro-environmental parameters. The weight of each portion was controlled within 2 ± 0.02 kg. Group I was used to simulate ambient temperature transportation; group II was used to simulate the ice-added transportation (two 200 mL ice-bags were placed in each independent packages); Group III was used to simulate the pre-cooling transportation, which was placed in a refrigerated warehouse (temperature was 0–1 °C for the first 12 h). The acquisition frequency of sensors was 27 s/time, and the quality indicators were tested twice a day at 8 am and 5 pm, respectively.The hazard analysis and critical control point (HACCP) is a quality control system that ensures the quality and safety of food by identifying, evaluating, and controlling various hazards in food production, processing, sales, and consumption. It has been widely used in the food industry, especially in the cold chain logistics of fresh fruits or vegetables, meat and seafood ,45. The In order to evaluate the quality of fresh sweet cherries, critical quality indicators were selected, including chromatic aberration , hardness, pH, and soluble solid content (SSC). Ten random sweet cherries were measured twice a day at 8 am and 5 pm respectively. Detailed parameters of the measurement devices were shown in The chromatic aberration was measured by the CR-410 chromatic aberration analyzer . RH: Relative humidity. To reduce the error caused by uneven color on the surface of sweet cherries, the peaks on both sides and the middle position of the sweet cherries were measured, and then the three values were averaged to obtain the final value of the chromatic aberration . Among them, the values of the brightness L*, the red value a*, and the yellow value b* were directly obtained by measurement, but to integrate the effects of the three parameters, the value of the total chromatic aberration ΔE was calculated by the following formula :(3)ΔE=[. The peaks on both sides of the sweet cherry were measured, and the penetration speed was controlled at 0.5mm/s. The maximum value was not recorded until the peel of sweet cherries was punctured, then the average value of the two measurements was obtained.The pH was measured by Testo 205 (produced by Testo SE & Co. KgaA). Before measurement, the pH probe was washed with distilled water and cleaned with a dust-free paper, then the probe was stabbed into the two peaks of fruits, and the data was recorded after the displayed value was stable. The final value was the average value of the two measurements.The soluble solid content (SSC) was measured by a hand-held digital refractometer (manufactured by ATAGO Corporation). Before measurement, the prism part on the refractometer was washed with distilled water, then the dust-free paper was used to clean the remaining water, then 2–3 drops of juice were apply to the surface of the prism. The displayed value was recorded after stable. Each fruit was tested twice, and the final value is taken as the average of two measurements.Through the relevant literature and field research in Yantai City, a typical business flow  of sweet cherries in China was summarized and the hazard points, as well as corresponding control measures were analyzed based on Hazard Analysis and Critical Control Point (HACCP), the business flow and hazard analysis and critical control points could be seen in Step Ⅰ: Harvesting (production link). Sweet cherries generally ripen from May to July, and picking is usually carried on a sunny morning when the outdoor temperature is around 25 °C. The purpose is to keep the temperature of sweet cherries at a low level, thereby reducing the risks of quality deteriorates due to high temperature.Step Ⅱ: Sorting and grading (production link). After harvesting, the sweet cherries are sorted and graded by workers or machines within 2 h. The purpose is to remove fruits that are broken or damaged by pests and diseases, and put together fruits of the same size and maturity.Step Ⅲ: Packaging (production link). A certain weight of sweet cherries is put in a polystyrene foam plastic box and sealed with tape, and then waiting for the next step of processing or directly shipped to the local market for sale.Step Ⅳ (Model 1): Local sales (circulation link). In order to meet the needs of the local market, some sweet cherries are sold locally after packaging, which is usually completed within 1–2 h;Step Ⅳ (Model 2): Short-distance transportation (circulation link). To meet the needs of the surrounding market, sweet cherries are transported to the nearby towns through light-van for sale, which is generally completed within 3–5 h;Step Ⅳ (Model 3): Express transportation (circulation link). With the development of the Internet economy and express industry in China, online sales account for an increasing share in sweet cherry sales models. Sweet cherry is firstly packaged and then distributed to different cities through express logistics, which usually requires an average of 6–72 h. To ensure the taste of sweet cherries and reduce the quality loss during the transportation process, ice bags are usually added in the express package;Step Ⅳ (Model 4): Long-distance transportation (circulation link). Some sweet cherries are immediately sent to the cold storage for pre-cooling after packaging. The pre-cooling temperature is generally 0–1 °C and the pre-cooling time is around 12 h, which can fully dissipate the field heat, reduce the core temperature of fruits, slow down the respiration rate and extend the shelf life of sweet cherries. After the full pre-cooling, the sweet cherry is transported to distant cities by cold chain trucks immediately, and the transportation time generally no less than 72 h;Step Ⅴ: Terminal clients (consumption link). Terminal clients include wholesalers, retailers, and consumers. Lots of refrigerated shelves are used in wholesalers and retailers (mainly supermarkets) to ensure that the temperature and relative humidity are within an appropriate range for reducing quality loss. The express transportation mode directly delivers sweet cherries to consumers, completing the entire transportation chain structure.2, CO2 and C2H4), the quality of sweet cherries are changing constantly during transportation. The mechanism of quality changes in express logistics was analyzed in The sweet cherries are still a living organism after harvesting, which means respiration, transpiration and other metabolic activities are still going on ,48. UndeThe temperature and relative humidity have an important effect on the quality of sweet cherries in express logistics. During this process, temperature directly affects a series of physiological activities of sweet cherries, such as respiration (aerobic respiration and anaerobic respiration), transpiration, and biosynthesis activity (such as ethylene synthesis). The relative humidity directly affects the water loss and inhibits hydrolysis as well as reduces the respiration intensity of sweet cherries . The tem2 accumulation (20%), which showed by the increase in respiration rate (aerobic and anaerobic respiration), biosynthesis of fermentative volatile metabolites, and sensory perception of off-odors [The gas content in the express logistics microenvironment also has an important effect on the quality of sweet cherries. R. Cozzolino et al. (2019) found that in low oxygen microenvironment (about 1%), sweet cherries were sensitive to COff-odors . Althougff-odors .When the microenvironment is in a state of high oxygen and low carbon dioxide, the respiratory rate of sweet cherries is high. The oxygen in the microenvironment was consumed, and the carbohydrates and organic acids were converted into energy, carbon dioxide, and water by enzymatic reaction , which cThe changes of temperature and relative humidity in the microenvironment of sweet cherries in express logistics were shown in As can be seen from The relative humidity of the three groups reached 90% in a short period and then remained stable in the range of 90% to 98%. The ice-added group spent the longest time to reach 90% relative humidity, for about 6.8 h. The pre-cooling group showed the fastest speed, the relative humidity of the microenvironment had reached 90% after 2.2 h. The ascent speed of ambient temperature group was middle, the relative humidity reached 90% after 3.9 h. According to previous studies, the most suitable temperature and relative humidity for the storage of sweet cherries were 0–1 °C and 90–95% relative humidity. From the 2 content was gradually decreasing, the CO2 and C2H4 content were gradually increased. This phenomenon is closely related to the metabolism activities of sweet cherries (including aerobic and anaerobic respiration). The respiration activity of sweet cherries consumes the O2 and emits CO2 and C2H4 during the whole express transportation.The variation of gases content in the microenvironment of sweet cherries under three different express transportation modes is shown in 2 content, the O2 consumption rate of the ambient temperature treatment was the fastest (about 0.038%/min). In the S1 and S2 phase, the O2 content dropped rapidly. More specifically, the ice-added group showed a higher rate of O2 consumption than that of pre-cooling treatment in the S1 phase, while the rate was exactly the opposite in the S2 phase. The O2 content remained at a stable level .In terms of O2 content, the CO2 content in the ambient temperature group indicated the fastest increase compared with the other two groups. In the S1 phase, the growth rate of CO2 in the ice-added group (0.0104%/min) is greater than that in the pre-cooling group (0.0098%/min), while an opposite trend was presented in the S2 phase, which also corresponded to the consumption of O2 content. Finally, in the S3 phase, the CO2 content leveled off at 10.559%, 8.362% and 9.338% respectively.As for CO2H4 content after harvesting compared with climacteric fruits (such as apple and banana). The possible reason was that the O2 content in the sealed box was too low to continue the aerobic respiration of sweet cherries, and anaerobic respiration became the main mode of respiration to provide energy. When the O2 content in the microenvironment less than 1%, the rate of anaerobic respiration was accelerated, the content of ethanol and acetaldehyde in the fruit increased rapidly, and the flavor of the sweet cherry also decreased.In general, ethylene content maintained an upward trend during the experiment period, but the content and variation range was very small. The three experimental groups reached the maximum  in the late stage of the S2 phase, and then the ethylene content decreased slightly in the S3 phase. Since the sweet cherries are considered as non-climacteric fruits, and the respiration rate has been declining after harvesting, there is no obvious increase in CFrom the perspective of temperature and relative humidity changes, the pre-cooling treatment could more effectively suppress the temperature increase compared to the ambient treatment or ice-added treatment, although the high relative humidity could be caused at the same time. From the perspective of the changes of the three gases, when the transportation time is less than 10 h (about 600 min), the pre-cooling treatment has the most obvious inhibitory effect on the physiological metabolism (such as respiration) of sweet cherries; while the transportation time is greater than 10 h, adding ice packs in the express package may have a better effect. Since the changes in gas content were also affected by the temperature and relative humidity, the analysis from the perspective of the change of gas content was more guiding significant.The quality indicators change of sweet cherries during the express logistics could be seen in 2, CO2, and C2H4 content were used as the input of the prediction model. In total, 7000 sets of data were selected for training the prediction model, and the remaining 2000 sets of data were used for testing and evaluation of the predictive model. The predicted and actual values of freshness in three different express logistics conditions were obtained, and the absolute and relative errors between the predicted and true values were shown in According to the construction steps of the prediction model in section two, the OAs can be seen from 2, CO2, and C2H4) compared with the traditional monitoring system (only monitoring of temperature and relative humidity), the accuracy of each sensing unit was higher, response time and recovery time were shorter, and the DMQAS could accurately predict the freshness of sweet cherries through prediction model based on BP neural network, which could provide a reliable reference to stakeholders for decision-making and improving express logistics management. Overall, the quality loss rate decreased by 10%–15%, and the market price of fresh sweet cherries increased by about 50% (the market price increased from about 40 yuan/kg to 60 yuan/kg), which greatly reduced the quality and economy loss.The DMQAS were evaluated and discussed through questionnaires and interviews with stakeholders in the whole process, and relevant feedback was collected for promoting the improvement of DMQAS. After the questionnaire survey and interviews, it was found that the DMQAS could real-time accurately monitor critical parameters in the express logistics microenvironment of fresh sweet cherries. 2, CO2, and C2H4) in real-time during express logistics, and can also accurately predict the freshness of sweet cherries (the relative error can be controlled within 10%). Through the data analysis, it is found that the pre-cooling treatment is suitable for a short duration (<10 h) express logistics, and the ice-added treatment is more effective for a long duration (>10 h) express logistics. Combined with the quality parameters , the DMQAS could provide theoretical reference for timely decision-making and logistics management, the quality loss of the sweet cherry was reduced to 15% from 25%–30%, and the market price of sweet cherry increased from 40 yuan/kg up to 60 yuan/kg via evaluation.This paper presents dynamic monitoring and quality assessment system (DMQAS) based on multi-sensors, for reducing the quality loss of fresh sweet cherries in the express logistics. The system can monitor key micro-environmental parameters (temperature, relative humidity, OAlthough the DMQAS can meet the basic needs of the actual process, the sensors currently used are rigid and bulky, which may cause secondary damage to fruits. In the future, the DMQAS will integrate flexible micro-sensors, which could be adhered to the express packaging to achieve non-destructive monitoring. Future research will also focus on adding new sensing units to apply the DMQAS to other product logistics scenarios or adding dynamic real-time adjustment devices to achieve the function of remote real-time quality control.


Orthogonal test method was applied to analyze the strength properties of basalt-polypropylene mortar. The effect of basalt fiber length, polypropylene fiber length, basalt fiber volume content and polypropylene fiber volume content on the 28 d cube compressive strength and flexural strength were investigated. Test results show that comparing with flexural strength, the influence of basalt fiber length and polypropylene fiber length on compressive strength of mortar was greater than on flexural strength. The length of polypropylene fibers contributes the highest to the flexural strength. The effect of basalt fiber on mortar strength is the largest with 6 mm length and 4% content. Polypropylene fiber length has the greatest influence on the compressive strength of fiber mortar, followed by basalt fiber volume content. Volume content of polypropylene fiber has the greatest influence on flexural strength of fiber mortar, followed by polypropylene fiber length. According to the scoring of the efficacy coefficient method, the best ratio combination for compressive and flexural strength was the basalt fiber length of 9 mm, polypropylene fiber length of 6 mm, basalt fiber volume content of 4% and polypropylene fiber volume content of 4%. Compared with the blank samples, the 28 d compressive strength and 28 d flexural strength of the cement mortar samples were increased by 27.4% and 49% respectively. According to the test results, the properties of the fiber were analyzed and evaluated and the mechanism of fiber action and fiber microstructure were analyzed. Cement matrix composite is a kind of engineering material with cement as the cementing material . The whoAdding fiber into the matrix is an effective means to obviously improve the mechanical properties of cement matrix composite, especially the toughness. Therefore, a large number of scholars are paying increasing attention to fiber-reinforced cement matrix composite. Most of the research is aimed at a single variety or a single length of fiber but this can only focus on the enhancement of a certain performance ,6,7,8. RIn the research of hybrid fiber cement matrix composite, the most common one is mixing steel fiber and polypropylene fiber ,14,15,16The key to mixing fibers is the size and content of each fiber. Short fiber has a greater effect on strengthening concrete, while long fibers play a greater role in strengthening concrete toughness . The conIn this paper, the effect of basalt-polypropylene fiber on the 28 d performance of cement mortar was studied. Through orthogonal experiments, the influences of basalt fiber length, polypropylene fiber length, basalt fiber volume content and polypropylene fiber volume content on the compressive and flexural strength of cement mortar were respectively studied. The maximum influence unit of each influence factor on different indexes and the matching combination when the mechanical properties reach the optimum are obtained. Finally, the causes of fiber reinforced cement-based materials were further analyzed through fiber action mechanism and microscopic mechanism analysis.The cement adopts ordinary Portland cement with strength grade of 42.5 and its quality meets the requirements of the current national standard GB175-2007 “General Portland Cement”. The sand was common river sand with fineness modulus of 2.36. The mixing water was tap water from Chongqing area, which meets the quality requirement of water in the specification. The water-reducing agent was a polycarboxylic acid water-reducing agent with a water reducing rate of 26% produced by Shanghai Chenqi chemical technology co., Ltd. . The test fibers were chopped basalt fibers produced by Haining Anjie Compound Material Co., Ltd.  and bundled monofilament polypropylene fibers produced by Shanghai Chenqi Chemical Technology Co., Ltd. The physical and mechanical properties of the two fibers were shown in In order to explore the influence of basalt fiber length (A), polypropylene fiber length (B), basalt fiber volume content (C) and polypropylene fiber volume content (D) on the mechanical properties of cement mortar, the experiment adopts orthogonal test method and the factor-level was shown in 5) orthogonal table was selected, as shown in Orthogonal experiment was designed according to the selected factor-level and L16 °C and a relative humidity of more than 95%.Seventeen groups of test pieces were respectively made with the above mixture ratio and the arithmetic average value of three test pieces in each group was taken as the compressive strength or flexural strength of the test pieces. The compressive strength test adopts microcomputer-controlled full-automatic pressure testing machine, model YAD-2000 , pressure speed was 1.0 kN/s and the flexural strength test adopts DKZ-5000 electric flexural testing machine . When the difference between one of the maximum or minimum values of the three measured values and the intermediate value exceeds 15% of the intermediate value, the maximum value and the minimum value were eliminated together and the intermediate value was taken as the compressive strength or flexural strength value of the restructured specimen; If the difference between the two values and the intermediate value exceeds 15% of the intermediate value, the experimental results of this group of test pieces were invalid.The test results of 28 d compressive strength and flexural strength of basalt polypropylene fiber mortar were shown in The range analysis method was referred to as R method, which distributes the multi-factor and multi-level test evenly through fewer test times, so as to improve the test efficiency . It consjmy corresponding to m level in column factor j. jmK was the expected value of jmy, that is, the average value of jmy, jR was the range of the column j factor, same as, the difference between the maximum value and the minimum value of the index value at each level of the column j factor.Among them, j factor and the optimal level combination of each factor can be judged, that is, the optimal combination. The magnitude of jR can be used to judge the variation range of test indexes when the level of the factors in column j changes. The larger jR, the greater the influence of this factor on the test index and therefore the more important it is. Therefore, according to the size of the extremely poor jR, the primary and secondary factors can be judged.According to the size of According to the data in As can be seen from the data in Analytic Hierarchy Process (AHP) is a method of hierarchical analysis of complex problems . It comb(i)A), namely basalt fiber length (A(1)), polypropylene fiber length (A(2)), basalt fiber volume content (A(3)), polypropylene fiber volume content (A(4)) and the third layer was the factor level, namely each factor was divided into four levels. From left to right, let’s call that As shown in j of factor (i)A was denoted as ijK, which was called the effect of column j of factor (i)A on the test . The effect weight was calculated by Equations (4)–(7).The sum of the test data at the level of column A represents the horizontal layer which affects the test effect matrix; C represents the influence of factors on the experiment weight matrix. The influence weight of each factor level on the test index was calculated as: w = ASCT, it indicates the influence of various factors and levels on the test indexes [ indexes .Using this model computed the relative weighting of every factor level and the results was shown in As shown in According to the orthogonal test method, the 28 d compressive strength and flexural strength investigated are called indexes. The average strength of each factor at each level can be obtained from the visual analysis table, as shown in As can be seen from As can be seen from As can be seen from As can be seen from The range analysis method has been carried out previously but since the range analysis method cannot estimate the error in the test process and the test result determination and cannot distinguish the data fluctuation caused by the change of test conditions from the data fluctuation caused by the error, in order to make up for this shortcoming, the variance analysis method was adopted to distinguish the difference and error in the test result caused by the change of factor level. At the same time, the contribution rate analysis can further confirm the influence of factors on indicators . The resFrom From The efficacy coefficient method can comprehensively evaluate multi-objective problems. According to the orthogonal test results, the maximum and minimum values of 28 d compressive strength value and flexural strength value were selected as the satisfactory value and impermissible value of the efficacy coefficient method index evaluation system . The speAccording to the satisfactory value and impermissible value of each index, the efficiency coefficient value of each index was calculated and the formula is following:The results are shown in According to the calculation result of efficacy coefficient, the best performance for the compressive strength was specimen 12 and its ratio combination was A4B1C2D4; for the flexural strength, the best performance was specimen 14 and its ratio combination was A2B2C4D4. According to the comparison of the total efficacy coefficient values, the total efficacy coefficient score of test piece 14 was the highest, which was 95.38. Therefore, combining the three strength indexes, the best matching combination was A2B2C4D4. Compared with the blank test piece, the compressive strength of test piece 14 was increased by 27.04% and the flexural strength was increased by 49%.An appropriate amount of polypropylene fiber was mixed into cement mortar to form a uniform three-dimensional random support system, which can reduce segregation and bleeding of the mixture and the bridging effect of polypropylene fiber can also limit further crack propagation during cracking process. When the fiber content is too large, the fluidity of the mixture will decrease rapidly and the matrix will be hard to be compacted. Basalt fibers form a spatial grid structure inside the mixture structure, which plays a role on supporting aggregates, reducing segregation and bleeding of the mixture and can also inhibit the propagation of microcracks in the matrix through bridging. Due to the small diameter of basalt fibers, the fibers are easy to intertwine with each other during the dispersion process in cement mortar, resulting in “agglomeration”.Due to the large gap in diameter and elastic modulus between polypropylene fiber and basalt fiber, the two fibers can form a “gradation” when they were reasonably matched, thus forming a more uniform and dense spatial network structure in the mixture, weakening the unfavorable conditions in the mixing and forming process and limiting the generation and development of shrinkage microcracks and plastic settlement cracks in the hardening process. In the loading process, basalt fiber firstly limited the propagation of microcracks. As microcracks fuse and coalesce into larger cracks, the basalt was gradually pulled out. In this process, polypropylene fiber also gradually played the bridging and bearing role, which limited the further growth of the crack. Finally, the overall performance of the cement matrix was improved by the combination of the two fiber and produce a positive hybrid effect.The simultaneous incorporation of the two fibers into the cement matrix will increase the total amount of fibers, which may lead to poor workability of the mixture, thus reducing the compactness of the cement matrix. In addition, if the mixing content of polypropylene fiber and basalt fiber was unreasonable, the two fibers will affect each other in the mixing process, resulting in uneven fiber dispersion or intertwining, agglomeration and formation of more weak areas, thus greatly reducing the compactness of cement matrix, which will degrade its various mechanical performance indexes and produce negative hybrid effect.This paper summarizes the previous research results and analyzes the reasons for the strength of fiber-reinforced cement-based materials from the microstructure with the aid of Phenom scanning electron microscope (SEM). As can be seen from Through the analysis of orthogonal test results, it was found that the influence of each factors on 28 d compressive strength was the polypropylene fiber length > basalt fiber volume content > polypropylene fiber volume content > basalt fiber length; The effect on 28 d flexural strength was the basalt fiber volume content > polypropylene fiber length > basalt fiber length > polypropylene fiber volume content.When the basalt fiber length increased from 6 to 9 mm, the compressive strength of mortar specimens increased by 15.79% but when the basalt fiber length increased from 9 to 18 mm, the compressive strength of mortar specimens decreased by 7.88%. When the basalt fiber length increased from 6 to 9 mm, the flexural strength of mortar specimens increased by 1.86% but when the basalt fiber length increased from 9 to 18 mm, the flexural strength of mortar specimens decreased by 3.66%. Therefore, the best selection range of basalt fiber length can be determined to be 6–9 mm.When the length of polypropylene fiber increased from 3 to 6 mm, the compressive strength decreased by 19.93%, the length increased from 6 to 9 mm, the compressive strength increased by 19.50%, the length increased from 9 to 19 mm and the compressive strength decreased by 1.28%. When the length of polypropylene fiber increased from 3 to 9 mm, the flexural strength of mortar specimens increased by 4.57% but the length of polypropylene fiber increased from 9 to 19 mm and the flexural strength decreased by 0.96%. Thus, the optimal selection range of the length of polypropylene fiber was determined to be 6–9mm.When the volume content of basalt fiber increased from 1% to 3%, its compressive strength increased by 7.67% and the content of basalt fiber increased from 3% to 4%, its compressive strength decreased by 18.59%. The volume content of basalt fiber increased from 1% to 3%, the flexural strength of mortar specimens increased by 6.12%, while the content of basalt fiber increased by 4% but the flexural strength decreased by 4.13%. Thus, the optimal selection range of the content of basalt fiber was determined to be 2%–3%.The compressive strength of mortar specimens decreased by 9.76% when the polypropylene fiber content increased from 1% to 2% but the compressive strength of mortar specimens increased by 15.82% when the polypropylene fiber content increased from 2% to 4%. When the volume content of polypropylene fiber was increased by 2% from 1%, the flexural strength is increased by 2.53%, from 2% to 3%, the flexural strength is increased by 0.62%, from 3% to 4% but the compressive strength was decreased by 1.58%, the best selection range of the volume content of polypropylene fiber can be determined to be 2%–3%.The best combination of compressive strength was the basalt fiber length of 18 mm, polypropylene fiber length of 3 mm, basalt fiber content of 0.2% and polypropylene fiber content of 0.4. The best combination of flexural strength was the basalt fiber length of 9 mm, the polypropylene fiber length of 6mm, the basalt fiber content of 0.4% and the polypropylene fiber content of 0.4. According to the efficiency coefficient value, the best combination of comprehensive strength was that the basalt fiber length was 9 mm, the polypropylene fiber length was 6mm, the basalt fiber content was 0.4% and the polypropylene fiber content was 0.4%.After systematic analysis of basalt-polypropylene fiber mortar, the following conclusions were obtained: