The valorization of aluminum dross for Al recovery was performed via its mixing with metallic copper to produce Al-Cu alloys. This approach was with the intention of establishing a new smelting process to treat the dross with Cu scrap use. To evaluate the high temperature interaction of the materials, the wettability of a Cu-containing aluminum alloy with the non-metallic components of the dross was studied by the sessile drop method. It was found that the wetting was weak via temperature changes at 973–1373 K, and consequently no proper metal separation occurred. To better separate the metallic and non-metallic phases with larger density differences, a higher Cu portion was considered to obtain a significantly denser metallic phase, and it was found that partial separation of the Al in an Al-Cu alloy is possible. The complete separation of the metallic components of the dross was, however, experienced by the dross and copper melting with the addition of pre-melted calcium aluminate slags at elevated temperatures. It was found that Al-Cu alloys were produced and separated from the adjacent slags, and the aluminum oxide of the dross ended up in the slag phase. Moreover, the characteristics of the produced slags depend on the process charge. Pure nitrides ,10. The nitrides . Generalnitrides ,7.2O3 i.e., around 75% Al, and below 5% of salts [Aluminum White Dross (AWD) forms during the primary production of aluminum and contains a high percentage of Al and Alof salts . Aluminuof salts ,14,15,16of salts . Aluminuof salts . The recYθ  was studied to obtain a proper understanding about the mechanisms of high-temperature interaction between liquid aluminum alloys with the non-metallic components of the AWD. A full understanding of this mechanism will allow for the effective separation of the metallic phase from the Al dross material (mainly oxide phases), which may contribute to more effective recycling of aluminum dross. The wetting and spreading behavior of liquid aluminum alloy on a surface of solid Al dross substrate is an important phenomenon that should be considered for improving the recycling of aluminum dross. Generally, the wetting of a solid by a liquid depends on the involving interfacial tensions between the three involved phases: solid/vapor (SV), solid/liquid (SL), and liquid/vapor (LV) . A valueθY  is an idterfaces . Consequterfaces :σsv − σsA detailed description of Young’s equation, the sessile drop method, and corresponding testing procedures are reviewed and available in Refs. ,23.The materials preparation and applied methodology are described as follows.The substrate for the wettability tests was performed from a commercial AWD  with a particle size below 1 mm. AWD was first collected from the skimmed dross over the surface of molten primary Al and an Al-Si-Mn alloy . To directly extract a representative Al dross sample, a special 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. The aluminum dross was subsequently subjected to a ball milling, and a detailed description of this procedure is reviewed in Refs. ,7. After2O3 synthetic-slag flux was added. Two different slag compositions were initially prepared: CaO/Al2O3 = 2 (experiment 2) and CaO/Al2O3 = 4 (experiment 3) via mixing pure CaO and Al2O3 powders (above 99% purity level), and then melting them in a top-open induction furnace at 1873 K in a graphite crucible  for 1 h. For the AWD melting trials, metallic Cu (99.99%) particles were added with sizes of 1–5 mm, and the charge mixture details are given in The above AWD was used for the melting tests; however, a particle size of 2–10 mm was used. In experiment 1, only the dross particles and Cu particles were mixed, with no flux addition. In experiments 2 and 3, a CaO-AlThe wettability experiment of the Al-Si-Cu/Al dross couple was carried out by the classical Sessile Drop (SD) method combined with a newly introduced Capillary Purification (CP) procedure  was introduced to the chamber to suppress the evaporation from the Al-Si-Cu alloy. During the experiments, the Al-Si-Cu/Al dross couple images were recorded by a high-speed digital CCD camera  at 50 frames per second, and then the images were processed to measure the change of contact angle values over time and to analyze the related wetting kinetics by using ASTRA 2 software. After the high temperature tests, the solidified couple was removed from the chamber and subjected to a structural characterization of the prepared cross sections by using the Zeiss Ultra 55 Scanning Electron Microscope , coupled with energy-dispersive X-ray spectroscopy .After placing the alloy/substrate couple inside the chamber, gases were evacuated using Scroll  and turbo-molecular pumps . When pressure inside the chamber reached the value of about 1 × 10e 1373 K . At a teIn experiment 1, Al dross was mixed with pure Cu in the mass proportions of 40% and 60%, respectively. The mixture was charged into an alumina crucible and then in a graphite crucible, as schematically shown in The mixture in the crucible was subjected to annealing at a temperature of 1373 K for 30 min in a top-open induction furnace  described elsewhere [2O3 synthetic slags . After melting, the furnace power was turned off and, consequently, the molten components solidified. The metal was much heavier than the slag and it sunk down to the crucible’s bottom, as schematically illustrated in The obtained results are presented and discussed as follows.2 phase in these areas. The presence of a second dominant phase consisting of the Cu and Al elements was also found for the light grey phase that was analyzed by EDS analysis at four areas 2, 4  from the remaining non-metallic part. It was previously observed that melting of separated Al-rich particles of the dross does not yield the complete separation of the Al . Obvious2O3 slag flux was used to dissolve the non-metallic portion of the dross into a co-existing slag. These approaches were based on the results of wetting trials in The melting of separated Al-rich particles of the dross was performed in two approaches via changing the physical properties in the system for both the metallic portion and the non-metallic portion. Therefore, melting was performed by Cu metal addition to change the overall metal composition significantly and to a high Cu-containing alloy. Moreover, additional CaO-AlConsidering the macro views of the broken crucible after remelting, the division of the sample into two areas is possible, namely the area of the agglomerated part on top and the complete remelted part on the bottom. The percentage masses of the agglomerated and melted parts were determined to be about 44% to 56%, respectively. The induction melting of the mixture of Al dross with pure Cu contributed to homogenizing the structure of the completely remelted part, which consisted mainly of a metallic matrix of the copper-aluminum phase containing an average of 91 wt.% Cu and 7wt.% Al  with areas 1 to 3 in 2O3 synthetic slags and Cu indicated that, in experiments 2 and 3, two complete separable metal and slag phases were obtained, as shown in To overcome the challenges in metal separation through the simple induction melting described in 3Cu4 phase. The microstructural analysis of the dark grey phase revealed that it was composed of an average of 54.7 wt.% Cu and 42.4 wt.% Al , which is anticipated in the slag.The results of elemental analysis of the produced slags indicated that in both cases the dominant phases were calcium aluminates b,d. In e2O3 = 2 , the che2O3 = 2 b, which  diagram ,49. Thes2O3 = 4  is used. When CaO is used in the melting process, the Aloduction ,51.The temperature change in the range of 973–1373 K did not affect the wettability of the Al-Si-Cu alloy/Al dross system; the couple was a non-wettable system with a contact angle in the range of 125–130 degrees.The melting of Al white dross and Cu particles yielded (I) an agglomerated fraction of metal and oxide in which the metallic droplets encapsulated in the oxide layer and (II) a completely melted/separated Cu-Al alloy settled under the agglomerated portion.The addition of an oxide flux  into the dross and copper mixture led to the complete separation of the metallic and non-metallic components of the dross.2O3 ratio and they can easily be engineered.In flux-assisted melting of dross and copper, the characteristics of the produced slag depend on the added flux properties and it was found that the phases in produced slag are dependent on the CaO/AlThe applied experimental procedure in the present study can be applied to characterize Al dross through the separation of metallic components into a Cu-Al alloy and non-metallic components into a slag phase.A process for Al dross and Cu slag valorization was introduced, which is sustainable and provides onsite recycling of Al from the dross.The Al recovery from white dross by the remelting with the addition of Cu with and without oxide flux addition was studied. Moreover, the wettability of Al dross by Al-Cu-Si alloy was experimentally investigated. The main conclusions of the present work can be summarized as:


The thickness of the silica shell and the morphology of the as obtained core@shell nanoparticles were studied by modifying the polar phase/surfactant ratio (ω), as well as the quantity and the insertion phase  of the tetraethylorthosilicate (TEOS) precursor, the quantity of ammonia and the reaction temperature. The morphology of the nanoparticles was monitored by transmission electron microscopy (TEM/HRTEM) while their composition probed by combined elemental analyses, thermogravimetry and EDX analyses. We report that not only the particle size can be controlled but also the size of the silica shell, allowing for interesting perspectives in post-synthetic modification of the shell. The evolution of the spin crossover properties associated with the change in morphology was investigated by variable temperature optical and magnetic measurements.Spin crossover (SCO) iron (II) 1,2,4-triazole-based coordination compounds in the form of composite SCO@SiO Microemulsion 1: an aqueous solution of Fe(BF4)2·6H2O (211 mg in 0.5 mL H2O) was added drop by drop and under vigorous agitation to a mixture Triton X-100 (1.8 mL), hexanol (1.8 mL) and cyclohexane (7.5 mL). Microemulsion 2: an aqueous solution of 1,2,4-triazole (131 mg in 0.5 mL H2O) was added drop by drop and under vigorous agitation to a mixture Triton X-100 (1.8 mL), hexanol (1.8 mL) and cyclohexane (7.5 mL). After 15 min, the two clear microemulsions were quickly combined and stirred overnight at room temperature. The mixture was washed with ethanol and diethyl ether and nanoparticles were collected by centrifugation at 4000 rpm during 5 min.Synthesis of [Fe(Htrz)2(trz)](BF4)@SiO2 nanoparticles (2–18) with a similar procedure to sample 1, while modifying the quantity  and the insertion phase of TEOS, the quantity of ammonia (25%), the ω ratio ([H20]/[Triton X-100]) and the reaction temperature following We obtained the syntheses of (BF4)·0.2H2O sample 1 synthesized without TEOS shows nanoparticles with platelet-like morphology with average length of ~155 nm and width of ~43 nm (The TEM image of the reference (BF4) bulk sample, particularly with vibrational modes at 1536 and 1497 cm−1, which can be attributed to the stretching deformation of the protonated and unprotonated triazole ligands, respectively [2 are hidden by those of the complex.Increasing the quantity of TEOS slightly increased the amount of SiOarticles . Bright-articles  10]. Th. Th2 in ca shell ,31. Therca shell . The simtroscopy . Clearlyectively . On the 2, which varies with the size of the particles. This result agrees well with the assumption that the TEOS molecules are located near the surfactant at the interface of reverse micelles. Similarly to the synthetic route A, a limited increase of the silica shell thickness was obtained while the quantity of TEOS increased.The same series of experiment with increasing concentration of TEOS was realized while introducing the TEOS silica source in the aqueous phase in order to check if such a strategy permits us to increase the thickness of the shell of silica around the spin-crossover nanoparticles. As for synthetic route A, synthetic route B emphasizes the decrease in the size of nanoparticles with the increase in the quantity of TEOS . On the 2 shell thickness of the spin crossover nanoparticles. In the same experimental conditions as samples 2 and 8 , TEOS was introduced also either in the independent starting microemulsion (synthetic route C) or directly in the final microemulsion following the micellar exchange (synthetic route D). In The next study consisted in probing in more detail the influence of the TEOS insertion phase on the morphology of the obtained nanoparticles. We have already seen that the insertion of the TEOS in the polar or apolar phases has no significant influence on the size and SiOIn order to try to increase more significantly the thickness of the silica shell, ammonia was added, as catalyst for the hydrolysis of TEOS, directly in the final microemulsion and after the addition of the silica precursor. In fact, ammonia was added after the micellar exchange and the addition of TEOS in order to avoid the destruction/oxidation of the spin crossover complex. Indeed, tentative experiments while introducing the ammonia in the starting microemulsion or in the final microemulsion but before the TEOS addition, resulted in the destabilization of the SCO core. The thin shell of silica formed after the TEOS addition (during 15 min) seems to be sufficient to protect the spin crossover core from the ammonia. It is also interesting to notice that the addition of ammonia induces an increase in the pH in the microemulsion from 4.5 to 8.2 amount is evidenced from the elemental and EDX analyses, which indicate for samples 15 and 18 a %Si versus %Fe of ca. 49% and 62%, respectively, for an assembly of nanoparticles; see 2 around 1160, 1095, 955, 800 and 470 cm−1, appear on the infrared spectrum and characteristic bands attributed to the SCO complex can be also observed . As shown in rved see . The inc2 shell of ca. 13 nm. Moreover, as expected and already reported by the group of Coronado BF4@SiO2 nanoparticles with lengths ranging from 250 to 20 nm while modifying well-known experimental parameters such as the temperature and the water-to-surfactant ratio. In the context of changing the nucleation and growth processes during the particle’s formation, the increase in temperature from 273 to 333 K led to a significant increase of the length of nanoparticles from ca. 100 nm to ca. 250 nm, while the decrease in ω from 10 to 5 led to a decrease of the length of nanoparticles from ca. 75 nm to ca. 20 nm. More surprisingly, we demonstrated that the quantity of TEOS and its insertion phase have a significant influence on the size of the spin crossover nanoparticles but a rather low effect on the thickness of the silica shell. In particular, a clear decrease in the length of nanoparticles was observed while increasing the quantity of TEOS from 155 nm without TEOS to 40 nm for 4 eq of TEOS. Such results tend to consider that the silica precursor localized in contact with the surfactant at the interface of the polar and apolar phases could modify the size of the micelles. On the other hand, a clear increase in the silica shell up to ca. 13 nm was obtained using ammonia as a catalyst for the hydrolysis and the condensation of TEOS. Spin-crossover properties probed by magnetic and optical measurements are similar with the previously reported bulk and nanoparticles samples. Only an increase in the residual fraction can be estimated from the magnetic measurements for the smallest (20 nm) nanoparticles. Finally, we reported that not only can the particle size be controlled but also the size of the silica shell. This possibility opens interesting perspectives according to targeted applications, since a thin shell can allow a strong interaction between the core and the molecules that can be grafted on the silica, while a thick shell can play the role of protection of the core and can also modify the mechanical properties of the composite materials.In conclusion, using a reverse-micelle technique, we obtained a series of core@shell type [Fe(H-trz)


Because few well-preserved hydrothermal chimneys have been found in terrestrial sedimentary rocks, research on paleo-thermal vents in geological history is relatively sparse. In this study, we present our original discovery of “hydrothermal chimneys” from the Chang 7 source rocks of the Triassic Yanchang Formation in the Ordos Basin, China, and provide the best evidence for deciphering hydrothermal activity preserved in the geological record . Three possible chimney samples  were collected for this study; they were interbedded with mudstones and oil shales, indicative of a deep-lake sedimentary environment. All three samples consist mainly of anhydrite, pyrite, and dolomite with the formation of mineral zoning across the walls of these structures, suggesting a sulfate-dominated stage and a carbonate-sulfide replacement stage. Moreover, their in situ geochemistry is characterized by high Eu, U, Th, Sr, Mn and U/Th ratios, which are typical indicators of hydrothermal vents. In addition, their S isotopes range from 7.89% to 10.88%, near the values of magma sulfur, implying a possible magmatic trigger for these hydrothermal vents. All this evidence shows that the Triassic sedimentary rocks of the Ordos Basin probably contain hydrothermal chimneys. Comparing ancient hydrothermal chimneys to modern hydrothermal chimneys, we should note the important implications of ancient chimneys; their formation mechanism may have been related to oil production, and they are possible indicators for future oil investigations. Further, they have great significance for studying the hydrothermal properties of primary dolomite. Based on the research results of different hydrothermal chimneys, scientists have classified them into 3 categories according to temperature and mineral composition: "black chimney", "white chimney" and "silicon chimney"4. Over the years, research on the cause and growth mechanism of hydrothermal chimneys has received attention from the international academic community. Reconstructing the formation environment and growth mechanism of the chimney body according to the different structural compositions of the chimney body is one of the important aspects. The development of related research also involves many topics, such as deep sea material circulation, energy transfer, the genesis of mineral deposits and even the origin of life6. However. The amount of research on hydrothermal chimneys in modern lakes is relatively low, and there is even less research on lacustrine hydrothermal chimneys in geological history. The reason is that although they are important specimens for studying hydrothermal mineralization and activity and extreme environments throughout geological history, ancient hydrothermal chimneys are easily destroyed during the burial process, and it is difficult to find complete samples. Fortunately, abundant samples of hydrothermal chimneys from the Chang 7 section of the Triassic Yanchang Formation in the Ordos Basin were recently discovered by our team. Their tubular shapes and inner and outer walls are fully developed, so they are particularly valuable. They have opened up a new way to study the structural characteristics and growth history of hydrothermal chimneys in continental basins in the Late Triassic. and provide an excellent opportunity for the comparative study of modern and ancient hydrothermal chimneys.A submarine hydrothermal chimney is a tubular structure formed by the eruption of hydrothermal fluid on the seabed. Its structure and chemical composition are closely related to the properties of the hydrothermal fluid from which the chimney body formed. In the wall of a chimney with a thickness of 1 to 3 cm, there are very large geochemical, thermal and mineral combination gradients. A chimney contains rich information about the properties of hydrothermal fluids and mineralization temperatures and records the growth process and growth history of the chimney body8 have also confirmed the occurrence of hydrothermal activity during the deposition of the source rocks. Based on research about modern hydrothermal deposition and submarine black chimneys, we study the morphology, material composition, structure, mineral characteristics, geochemical characteristics and formation stages of hydrothermal chimneys, and we compare them with chimney samples from modern ocean floors and continental hydrothermal activity and discuss their geological significance.High-quality source rocks have been developed in the Chang 7 Member of the Upper Triassic Yanchang Formation on the southern margin of the Ordos Basin. Previous studies4 km29. Its periphery is surrounded by Cenozoic fault basins. The western part of the basin is a tectonic thrust belt and the Liupan Mountains, and the southern part is the Weihe Basin and the Weibei uplift. The Jinxi flexural belt is located in the eastern part of the basin. The northern part of the basin is adjacent to the Yimeng uplift and the Hetao Basin uplift. The overall contours of the basin form a roughly north–south rectangle , pyrite (FeS2) 2) with textures matching those in mineralogically similar black plume particulate assemblages. Within chimney walls, a pyrrhotite-free sulfide and carbonate assemblage of coarser, more euhedral FeS2 (pyrite and/or marcasite), dolomites and calcites is present. These sulfides and carbonates often replace anhydrite outward along crystallographic planes in the sulfate  Fig. d and dolS2) Fig. 2) with tS2) Fig. 2) with tS2) Fig. 2) with tS2) Fig. 2) with tS2) Fig. 2) with tFrom the bottom layer to the top layer, the researcher collected 11 samples of mudstone, 4 samples of argillaceous siltstone, and 20 samples of hydrothermal sedimentary rock from the Chang 7–1 section of the Yanchang Formation of the Triassic in the Zh22 well, with a total of 35 samples, in which hydrothermal chimneys were found in samples 1551.6, 15,516.-2 and 1574.4. During the sampling process, the influence of the mechanical differentiation on sediment composition and the tendency of sampling differences are minimized or eliminated. The sample collection and processing are described: ① Three samples about hydrothermal chimney were ground into ordinary rock flakes. After observing the sedimentary structure of the rock specimen and the composition, microstructure and fluorescence characteristics of the mineral under the microscope, the samples with complete morphology were selected to be made into electron probe sheets and SEM samples to determine the main elements, mineral components and microscopic mineral structure. ② The geochemical composition of pyrite particles, coarse-grained dolomite and coarse-grained calcite was further analysed with LA-ICP-MS. Since the laser beam spot of this method is 36 μm, which is much larger than that of micro-crystalline minerals and secondary enlarged mineral particles, only coarse-grained mineral particles can be analysed. ③ For the preparation of SEM samples, according to the needs of the experiment, a cube of 0.5 × 0.5 × 0.5 cm was made. The surface structure of the 6 sections was intact and was not damaged. It was used after being sputtered with gold for conductive treatment. After completing the above work, the rock samples were selected according to the characteristics of the samples and the research needs for the main and trace elements, scanning electron microscopy and other tests.238U + , while keeping the ThO+/Th+ ratio below 0.5% and the U+/Th+ ratio close to 1 for the reference glass 10.A total of 48 sets of data were completed for in situ trace element and rare earth element experiments, which were completed at the State Key Laboratory of Continental Dynamics, Northwest University. using an Agilent 7500 ICP-MS instrument attached to a 193 nm excimer laser ablation system (Geolas 2005). All measurements were performed in time-resolved mode with helium as the carrier gas. The carrier flow was optimized to obtain the maximum signal intensity for -8A, beam spot 1-5 μm) and an X-ray energy spectrometer  to analyse the main elemental constituents and contents of the different compositions of hydrothermal minerals, such as iron dolomite and pyrite.The main element was tested using a JXA-8100 electron probe system  and the control sample .The mineral characteristics and structure of the rock samples were observed using SEM  and an environmental SEM . The observation range is approximately 1 cm34S/32S ratio of the standard sample and the sample point was obtained by direct test, and the δ34SCDT value was calculated by the external standard correction (SSB method). The standards used were the international sulphide standard NBS-123 sphalerite and the laboratory internal standard WS-1 pyrite .Sulphur isotope analysis of pyrite was completed at the State Key Laboratory of Continental Dynamics, Northwest University. The laser ablation system was manufactured by Resso, model RESOlution S-155. The ArF excimer laser generator produces a 193 nm deep ultraviolet beam that is focused on the sulphide surface by a homogenized optical path. The diameter of the laser beam spot is generally 33 μm, the ablation frequency is 10 Hz, and the ablation is performed for 40 s. The high-purity helium gas is used as a carrier gas and mixed with argon gas and nitrogen gas to enter the mass spectrometer. The multi-receiver plasma mass spectrometer was manufactured by the Nu Instrument Corporation using the model Nu Plasma II. The The experimental analysis of electron probe, major elements, trace elements, rare earth elements and in-situ S isotope of the hydrothermal chimney samples in the study area has been completed. The specific experimental results are as follows:2, Al2O3, FeO and CaO are the four most abundant elements. In this study, 19 positions of the hydrothermal channel were selected to complete the electron probe test. The results are shown in the Table 2 contents of points 7 and 8 were 57.255% and 58.108%, respectively, and the remaining positions contained almost no SiO2. The Al2O3 content of points 7 and 8 were 34.92% and 33.91%, respectively, and the remaining positions had very small contents of Al2O3, ranging from 0.003% to 0.09%. The FeO contents of points 2 and 4 were 48.754% and 45.756%, respectively, and the remaining positions had very small contents of Al2O3, ranging from 0.86% to 3.298%. The CaO contents at points 1, 5, 6 and 9 were 55.696%, 55.355%, 60.486% and 58.097%, respectively, and the CaO content in the remaining positions was small. Other major elements, such as MgO, Na2O, K2O, MnO, TiO2 and P2O5, were rare. Except for point 3, the content of SrO was 0.052% to 0.846%, and the average content was 0.412. In the first four positions of sample 1551.6–2  seawater sulphur, usually characterized by a large positive value; (3) sedimentary sulphur, in which the sulphur isotopic composition varies greatly (− 40 ‰ ~ 50 ‰); and (4) mixed sulphur, involving the mixing of two or more different sources of sulphur, in which the level of the sulphur isotope is usually determined by the sulphur isotope composition and mixing11. A fifth source of sulphur includes the sulphur reduction of hydrogen sulphide and sulphur compounds by bacteria, which is generally less than -5‰. Petrological observations show that the Chang 7 high-quality source rocks have the characteristics of anomalous pyrite enrichment, with different morphologies, including octahedron self-crystals, irregular microcrystalline aggregates with framboidal filling, and large framboidal morphologies. This shows that during the Chang 7 sedimentary period, the sulphate supply required for pyrite formation was sufficient. The sulphur isotope data of pyrite in the source rocks of the Zh22 well are shown in Table 33Sv-CDT values of the 33 points ranged from 1.50 to 5.30, with an average of 4.883. The δ34Sv-CDT value ranged from 7.89 to 10.88, with an average of 9.591. The sulphur isotope characteristics of pyrite and raspberry pyrite in the Chang 7 high-quality source rock, the consistency of the sulphur isotopes of the pyrite in the longitudinal direction of the Chang 7 high-quality hydrocarbon source, and the similar sulphur isotope composition characteristics of tuff, aggregate pyrite and raspberry pyrite, reflect that sulphur compounds in hydrothermal activity at the bottom of the lake may be one of the important sources of sulphur.Traditional S, Pb isotope analysis mostly uses single mineral powder samples . It is difficult to guarantee the purity of single mineral particles, and it is difficult to separate the single mineral samples formed under different genesis. Simultaneously, it is difficult to finely distinguish the ring bands formed under different conditions for the sulphides of the developmental ring structure, so that the test results are often indicating multi-sources. Mixed values result in multiple solutions. NanoSIMS is capable of in situ micro-analysis of micron-sized pyrite. It can accurately analyse single mineral particles without destroying the particle structure and has high spatial resolution, which replaces the shortcomings of traditional analytical methods. There are four main sources of sulphur on the earth: (1) mantle sulphur (magma sulphur), δ12. Through comparative studies, the mineral composition and structure of the hydrothermal chimneys in this paper are very similar to those reported in previous studies on modern continental and oceanic hydrothermal chimneys. ① The channels of the hydrothermal chimneys found in the study area are similar in appearance to the drainage structure of the sedimentary rocks, but the two are essentially different. The drainage structure is mostly found in fine sandstone and black mudstone. The planes form irregular polygons, similar to the cracks on a turtle shell. The cracks formed by the drainage structure are limited to the layer and the irregular mesh structure. The sandstone in the lower part of the vertical section is liquefied, and the upper mudstone is located within fine veins and finally penetrates to the top surface of the mudstone to complete the discharge  × 10 triangle14 -MnO/TiO2 diagram15 -MnO/TiO2 discrimination diagram of the sediment  of a few centimeters to tens of centimeters in size, corresponding to the small-scale chimneys and their top nozzles in modern submarine chimneys. This is also a common feature of hydrothermal activity zones in other parts of the world 22. From the morphological comparison perspective, the Ordos Basin retains relatively complete paleo-hydrothermal nozzles, which are columnar with bifurcated channels. This arrangement is related to the low-temperature hydrothermal migration rate and the geothermal gradient in the continental rift. From the horizontal bedding developed in the oil shale in the study area, the hydrodynamic conditions at the bottom of the lake were weak. Hydrothermal chimneys are quickly buried and preserved by sediments after the growth and eruption stop. These are the reasons why hydrothermal chimneys of different scales are widely retained in this area with different enrichments.Modern black chimney research in the ocean shows that with the waning and end of hydrothermal activity and the effect of seawater dynamics, the black chimney body undergoes continuous erosion and disintegration; in addition, unstable components are dissolved, and eventually, a sulfide deposit is formed. In contrast to the long history of geology, the life span of a black chimney on the ocean floor after its formation is generally short, which is only a part of the sulfide depositional formation process18 have suggested that hydrothermal activity promotes the formation of high-quality source rocks. Hydrothermal activity not only provides thermal energy to promote the maturation of hydrocarbons but also causes the convection and circulation of water, bringing bacteria and minerals from the bottom of the lake to the surface water body, thereby promoting algae reproduction and increasing biological productivity. These conditions promote the formation of high-quality source rocks in the Ordos Basin(Fig. 23, the Escanaba Trough24, and the Okinawa Trough25. These findings provide a ‘natural laboratory’26 that not only sheds light on the petroleum generation process and the behavior of petroleum in high-temperature fluids but also provides a new perspective for the study of hydrocarbon organic matter sources and genesis. The study of hydrothermal chimneys in lacustrine oil shale will help deepen understanding of the development mechanism of source rocks in continental basins and lay a foundation for further research on lacustrine hydrothermal petroleum.The target layer with the hydrothermal chimneys is located in the Chang 7 section of the Triassic Yanchang Formation in the Ordos Basin and is a high-quality source rock in the study area. The traditional view is that this set of high-quality source rocks is a dark mudstone of the deep lake facies, which is related only to normal lake deposition. Some researchersasinFig. . In addiThe petrology, mineral assemblage, structure, geochemistry and isotopic characteristics of the samples show that there are lacustrine hydrothermal chimneys in the Chang 7 member of the Triassic Yanchang Formation in the Ordos Basin.The formation of the hydrothermal chimneys involved two stages and the formation of mineral zoning across the walls of these structures throughout two major growth phases: a sulfate-dominated stage and a carbonate and sulfide replacement stage. In the second stage, the hydrothermal fluid migrating outward from the center of the chimney dissolved and replaced anhydrite with carbonate and sulfide minerals.In the Late Triassic, the lake in the Ordos Basin had a great water depth, weak hydrodynamic conditions at the bottom of the lake, and an anoxic environment. The hydrothermal chimneys were quickly buried and preserved by sediments after the growth and eruption stopped. The hydrothermal chimneys are distributed in the black rock series in the center of the lake basin, which is a high-quality source rock. The study of hydrothermal chimneys in high-quality source rocks has provided new context for further understanding the development of petroleum.


Three major factors affecting productive performance of laying hens are BW, flock uniformity, and GIT development at the initiation of the laying period. Various feeding management practices to restrict feed intake of broiler breeders during the rearing phase to optimize BW for reproductive performance can improve BW uniformity. Hence, the feed restriction methods used for broiler breeders might be used to improve flock uniformity and the GIT development of laying hens. The objective of the study was to investigate the effects of energy-restricted feeding and switching to ad libitum feeding on the performance, uniformity, and development of Rugao layer breeders at the initiation of the laying period. Moderate energy restriction from 8 to 18 weeks of age and switching to ad libitum feeding can stimulate the development of the GIT and improve BW uniformity of layer breeders. Improved ECR was observed overall in the experiment. In addition, the BW of layer breeders recovered after the pullets were switched to ad libitum feeding for 3 weeks. These results provide a theoretical basis for the application of energy-restricted feeding in young layer breeders, which may have important practical importance for layer breeders because a better rearing cycle can be advantageous to production performance.n) content  from 8 to 18 weeks of age. The daily amount of feed was restricted to the absolute quantity of the diet consumed by laying hens fed 2850 kcal AMEn per kg diet ad libitum (control). From 18 to 21 weeks of age, all hens were fed a basal diet ad libitum. The body weight (BW) of the laying pullets decreased linearly with increasing energy restriction (p < 0.001) but recovered within 3 weeks of ad libitum feeding (p = 0.290). A gradual increase in the degree of energy restriction resulted in a gradual decrease in average daily weight gain (ADG) and a gradual increase in the feed conversion ratio (FCR) and energy conversion ratio (ECR) from 8 to 18 weeks of age . In contrast, the ADG and ADFI  gradually increased, while the FCR and ECR  gradually improved from 18 to 21 weeks of age. From 8 to 21 weeks of age, ECR improved (p = 0.005) with an increasing degree of energy restriction. The energy-restricted feeding for 6 weeks to the end of the trial improved BW uniformity (p < 0.05). The relative length and circumference of tarsus , and the relative weights and lengths of the small intestine, duodenum, jejunum, ileum, and caeca increased linearly  with increasing energy restriction at 18 weeks of age. After switching to ad libitum feeding for 3 weeks, the relative weights and lengths of the small intestine, duodenum, and jejunum of laying pullets increased linearly with increasing energy restriction . In conclusion, moderate energy restriction  from 8 to 18 weeks of age and switching to ad libitum feeding from 18 to 21 weeks of age can be used to improve BW uniformity and stimulate the development of the duodenum and jejunum of native layer breeders at the initiation of the laying period without compromising BW.The aim of this study was to assess the effects of energy-restricted feeding during rearing on the performance, uniformity, and development of layer breeders at the initiation of the laying period. A total of 2400 8-week-old Rugao layer breeders were randomly assigned to one of five groups (480 pullets per group) with eight replicates and were fed one of five diets that were nutritionally equal with the exception of apparent metabolizable energy corrected for nitrogen (AME The rearing period is one of the most important stages in the life of a laying hen and any mistakes made during this period cannot be corrected or adjusted during the subsequent laying period . The devPoor flock uniformity before the start of the laying period prevents maximum production because of suboptimal performance of both overweight and underweight hens . Low, asThe Rugao laying hen was approved as the national cultivated laying hen breed of China by the National Examination and Approval Committee of Domestic Animal and Poultry Breeds in 2009. It is typically used as the female parent of Suqin blue-eggshell chickens, which was approved as a crossbreeding system in 2013. The average BW of a Rugao laying hen is about 1.1 and 1.7 kg at 18 and 52 weeks of age, respectively . ConsequThe hypothesis tested in this study was that energy-restricted feeding in the earlier rearing period might improve flock uniformity of young layer breeders, but adversely affect BW. Also, ad libitum feeding can allow layer breeders to achieve the target weight and improve development of the GIT because of the higher feed and nutrient intake required for compensatory growth. The objective of the study was to investigate the effects of energy-restricted feeding and switching to ad libitum feeding on the performance, uniformity, and development of Rugao layer breeders at the initiation of the laying period.n values were 2850, 2750, 2650, 2550, and 2450 kcal/kg, respectively (n per kg diet (control). The amount of feed offered to the laying hens in the other groups was restricted to the absolute quantity of the diet consumed by the pullets in the control group. From 18 to 21 weeks of age, all experimental laying hens were switched to a basal diet  with eight replicates of 60 pullets each. From 8 to 18 weeks of age, the laying hens were fed one of five diets that were nutritionally equal except for apparent metabolizable energy corrected for nitrogen (AMEn) content. The calculated AMEectively . Feed wasal diet  formulatSamples of diets were ground to pass through a 40-mesh sieve and immediately frozen and stored at −20 °C for further analysis. The moisture contents of the diets were determined by oven-drying . Gross eThis trial was carried out at the Poultry Institute of the Chinese Academy of Agricultural Sciences  from July to October 2019. From 8 to 18 weeks of age, each replicate of 60 hens was randomly assigned to 20 cages of three hens each. From 18 to 21 weeks of age, all hens were transferred to a laying house and caged individually at a constant temperature of 24 ± 3 °C and relative humidity of 65–75%. Light exposure was limited to 8 h from 8 to 18 weeks of age and then increased by 1 h per week until the end of the experiment. One cage remained empty, and a chipboard was inserted into the feeders between the different replicate cages to prevent hens in one replicate from eating the feed of another. All animal handing protocols were approved by the Animal Care and Use Committee of the Poultry Institute (SYXK(Su)IACUC 2012-0029). Cage-side observations, which included recording any changes in clinical condition or behavior, were made at least twice per day throughout the study period.Individual BW and feed intake by replicate were measured on a weekly basis, and when mortality was recorded, the pullets were weighed. The average daily weight gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) were determined by period and cumulatively from these data. FCR is expressed as grams of feed consumed per gram of BW gain. In addition, the average daily energy intake (ADEI), expressed as kcal AMEn consumed per day, and the energy conversion ratio (ECR), expressed as kcal calculated AMEn per g BW gain, were also estimated by period and cumulatively.The pullets were weighed individually at weekly intervals and BW uniformity was determined by replicates, as described by Peak et al.  and GuzmAt 18 and 21 weeks of age, the tarsus length of all birds was measured with a digital caliper and the tarsus circumference was measured (at the midpoint of the bone) three times with a cotton thread, which was measured with a ruler with a precision of 1 mm. The relative values were calculated as a ratio to live BW.At 18 and 21 weeks of age, after fasting for 12 h, four birds from each replicate were killed by exsanguination and subjected to full postmortem examinations. The breast meat , thigh meat (including the thigh and drumstick), abdominal fat, head, wing, foot, heart, liver, spleen, lung, and kidney were weighed (paired organs were weighed together), and the ratios of weight to live BW were calculated.Afterward, the full proventriculus and gizzard were carefully excised, emptied of any digesta, cleaned, dried with desiccant paper, and weighed. Then, the number of papillae in the proventriculus was recorded. The relative values were calculated as the ratio to live BW. The length of each intestinal segment was measured using a flexible tape on a glass surface to prevent inadvertent stretching, as described by Lu et al. . The lenp ≤ 0.05.All data analyses were conducted using SPSS for Windows, version 16.0 . One-way analysis of variance followed by Duncan’s multiple comparison test was used to identify differences in means among treatments. Regression curve estimation was also used to determine linear and quadratic responses of hens to different energy restrictions. Differences were reported where p < 0.001, p < 0.001), and similar significant differences in BW were also observed after the switch to ad libitum feeding for the first and second weeks . There was no significant difference in BW among the groups after 3 weeks of the switch to ad libitum feeding (p = 0.290).The effects of energy-restricted feeding and switching to ad libitum feeding on the BW of the laying hens are presented in p < 0.001, p < 0.001), 13 to 18 , and 8 to 18 weeks of age . In contrast, a gradual increase in ADG and ADFI , and a gradual improvement in the FCR (p < 0.001) were observed from 18 to 21 weeks of age. The ADFI of laying pullets in the more severe energy restriction groups increased linearly after the switch to ad libitum feeding for the first and second weeks , then gradually decreased to a normal level relative to that of the control group in the third week  with increasing energy restriction from 8 to 18 weeks of age, whereas no differences were detected in ADG (p = 0.180) and mortality (p = 0.972).No treatment-related adverse clinical signs were observed. As shown in p < 0.001), 13 to 18 (p < 0.001), and 8 to 18 weeks of age (p < 0.001), and the ECR increased linearly from 8 to 13 (p < 0.001) and 8 to 18 weeks of age (p = 0.008) with increasing degree of energy restriction (p < 0.001), whereas the ECR improved linearly (p < 0.001) as the energy restriction levels increased from 8 to 18 weeks of age. From 8 to 21 weeks of age, a gradual increase in the degree of energy restriction from 8 to 18 weeks of age was associated with a gradual decrease in ADEI and a gradual improvement in ECR .The ADEI decreased linearly from 8 to 13 (triction . In contp > 0.05) were observed in the BW uniformity of pullets administered different energy restriction levels until 14 weeks of age. The BW uniformity was significantly improved from energy-restricted feeding for 6 weeks to the end of the trial (p < 0.05).The effects of energy-restricted feeding and switching to ad libitum feeding on the BW uniformity of the laying hens are presented in p > 0.05, p = 0.005), and the relative length and circumference of the tarsus increased linearly  with increasing energy restriction from 8 to 18 weeks of age. There was no statistically significant change in tarsus development after the laying pullets were switched to ad libitum feeding for 3 weeks.After 10 weeks of energy-restricted feeding, no statistically significant changes were observed in absolute tarsus length . However, there were no statistically significant changes in the carcass and visceral organ development after the laying pullets were switched to ad libitum feeding for 3 weeks.After 10 weeks of energy-restricted feeding, no statistically significant changes were observed in the carcass and visceral organ development , while the proventriculus papilla (PP) index tended to increase linearly (p = 0.066) with increasing energy restriction at 18 weeks of age  occurred with an increase in the degree of energy restriction at 18 weeks of age . Implementation of these commercial strategies can improve flock uniformity of laying hens. Available data on the influence of energy-restricted feeding during the rearing phases on flock uniformity of laying pullets are very limited for comparison with the results of the present study. In broiler breeders, qualitative diet dilution and skip-a-day management did little to increase flock uniformity relative to controls during the most intense period of feed restriction (7 to 19 weeks of age), but skip-a-day treatment, compared with qualitative dilution treatment, improved flock uniformity at 22 weeks of age . de BeerIn the current study, a gradual increase in the degree of energy restriction was associated with a gradual increase in the relative tarsus length and circumference, and a gradual decrease in the absolute tarsus circumference at 18 weeks of age, but no significant difference in tarsus development in pullets was observed at 21 weeks of age (after the switch to ad libitum feeding for 3 weeks). The tarsus length and circumference have been used to predict the growth and future size of birds ,7,29,30.In the current study, after 10 weeks of energy-restricted feeding, no statistically significant changes were observed in the carcass and visceral organ development with the exceptions of abdominal fat and liver (at 18 weeks of age). In addition, no statistically significant changes in the carcass and visceral organ development were observed after the switch to ad libitum feeding for 3 weeks. The results of this experiment are consistent with those of many studies of broilers. For example, Urdaneta-Rincon and Leeson  reportedn content, and the ADFI of laying pullets among the dietary groups remained the same from 8 to 18 weeks of age. Consequently, energy-restricted feeding from 8 to 18 weeks of age might stimulate the development and physiology of the GIT, thus improving nutrient digestibility to meet maintenance requirements. After the switch to a basal diet, the ADFI of laying pullets in the more severe energy restriction groups increased linearly after the switch for the first and second weeks, then gradually decreased to a normal level relative to that of the control group in the 3rd week, resulting in greater relative weights and lengths of the small intestine, duodenum, and jejunum. However, the differences in ADFI among the treatments were probably too small to produce any marked difference in the sizes of the proventriculus, gizzard, and other gut segments of the laying pullets. The potential beneficial effects of energy-restricted feeding from 8 to 18 weeks of age on the size and development of the GIT might not be long-lasting and may gradually disappear after feeding a common commercial layer diet.The relative weights and lengths of all gut segments, with the exception of the rectum, increased and the PP index tended to increase linearly with increasing energy restriction at 18 weeks of age. The number of papilla-like projections in the proventriculus is a measure of the proventriculus trait because each papilla can digest protein via the secretion of gastric juices . After tn/kg) from 8 to 18 weeks of age and switching to ad libitum feeding can stimulate the development of the GIT and improve BW uniformity of layer breeders, as flock uniformity was improved by energy-restricted feeding for 6 weeks to the end of the trial . Improved ECR was observed overall in the experiment. In addition, the BW of layer breeders recovered after the pullets were switched to ad libitum feeding for 3 weeks. Furthermore, these results provide a theoretical basis for the application of energy-restricted feeding in young laying pullets, which may have important practical importance for layer breeders because a better rearing cycle can be advantageous to production performance.The findings of the present study revealed that moderate energy restriction (down to 85.97% of ad libitum intake, 2450 vs. 2850 kcal AME


Construction of dams for hydroelectric power requires significant quantities of soil and rock, which are often extracted in borrow pits from adjacent regions. Although the effects of dams on stream processes has received significant attention, the effects of borrow pits has not. The main objective of this study was to analyze the geomorphological and sedimentological aspects of two second-order streams, one of which was directly affected by the borrow pit located upstream of its source (Pedra Branca stream). Flow rates were measured and cross-sections of 600m stretches in both streams were monitored over a hydrological year. At the same time, sediments from the bed of the channels and soils on their banks had their physical and chemical characteristics evaluated. Streams sediments differed in their chemical and organic matter composition. The mean particle size of the sediment particles was different between the reference and degraded streams. The water flow was very similar to both streams, only varying along the seasonal seasons. However, the fluvial channels presented great geomorphological differentiation, mainly downstream, due to the location of the Pedra Branca stream and its proximity to the borrow pit. Despite the great importance for the production of clean electric energy, the construction of hydroelectric plants promotes persistent impacts that affect structural and functional aspects of the adjacent aquatic habitats. Borrow pits used for the construction of projects become large sources of sediment for aquatic environments, affecting the drainage network of the hydrographic basin and the balance of river erosion, transport and deposition processes. The results show the need to review the intervention protocols in borrow pits and the environmental legislation that regulates their rehabilitation. The 20th century was marked by the construction of large hydroelectric plants in response to the demand for cheaper and cleaner energy  and hundThe negative impacts on water resources resulting from the construction of a hydroelectric plant are well studied and relatively well known ,9. HowevIn hydrographic basins where vegetation has been suppressed and the surface layers of soil have been removed, significant changes in the water cycle occur, with a reduction in infiltration rates and increased runoff . In manyStreams and rivers, like all geomorphological systems, are in a metastable dynamic balance . This baThis paper aims to describe the impacts of the borrow pits on hydrographic basins under their influence, an aspect that has not yet been explored in the assessment of the impacts of the construction of reservoirs in Brazil. Almost always, the effects caused by the borrow pits are neglected. The lack of cause and effect studies in the borrow pits promotes the lack of better defined protocols to mitigate the impacts that are caused by them. In this context, the main goal of the present study was to evaluate the impacts on the hydro-sedimentary balance of the Pedra Branca stream, whose source region was used as a soil borrow pit for the construction of the Emborcação reservoir . The following predictions were tested: (i) the erosive processes, strongly enhanced by the stripping and removal of soil from the borrow pit, promoted changes in the liquid discharge and in the sediments of the Pedra Branca stream; (ii) variations in the dynamic balance of the impacted stream, especially in the rainy season, lead to changes in its geomorphology; (iii) in response to hydro-sedimentological changes, there will be a change in the physical and chemical composition of the river sediments.The study site corresponds to a borrow pit from which soil was removed for the construction of the Emborcação Hydroelectric Plant (Teodomiro Santiago Reservoir). The degraded area (DA) resulting from the borrow pit covers an area of approximately 220 ha, and is located in the district of Pedra Branca, Catalão, GO (18° 26’0.00 "S and 47° 56’57.41" W). The DA includes areas with exposed soil (without any type of vegetation cover), with remnants of native forest , and vast portions with grasses. The DA has 19.5% of its area remaining from preserved forest, located within the limits of the studied area. Of the remaining 80.5%, 15.5% have grass vegetation and 65% have exposed soil; 76.7% of this is composed of the remaining B horizon and 23.3% of the C horizon. In the study region, the soil originally found was a red dystrophic oxisol, derived from migmatitic orthogneisses . The DA During a rehabilitation project carried out in the DA between 2001 and 2002, structures were built to collect and control rainwater drainage. The source and part of the bed of the Pedra Branca stream (degraded stream—DS), which was found partially silted , are alsThe region’s climate is predominantly Aw , with drFor the creation of hypsometric and use and occupation maps of the sub-basins of the studied streams, there were used images that were obtained by the sensors on board the satellites Sentinel-2 and ALOS (Advanced Land Observing Satellite), with spatial resolution of 10m and 12.5m, respectively. The images captured by Sentinel-2 provided the mapping of land use and facilitated the detailing of the physiognomy of rivers in the study area. The image captured by the PALSAR sensor (Phased Array L-band Synthetic Aperture Radar), on board ALOS, allowed to delimit the areas of the hydrographic sub-basins, as well as to develop a digital elevation model (DEM). The maps were made using the ArcGis 10.3 software.3/s), the slope of the RS and DS channels (m) and the granulometric and geochemical composition of the sediments.Three field campaigns were carried out over a hydrological year, in order to characterize the beginning of the dry season (May/19), the end of the dry season (September/19) and the end of the rainy season (March/20). Five points were defined along a stretch of 600 m in each stream (RS and DS) for river characterization and sampling. The length of the stretch was defined by the area where the stream was subjected only to the impact caused by the DA, that is, before the stream entered private rural properties, where it would be subject to other impacts, such as damming and grazing cattle. For the characterization, data on the physical and chemical conditions of the environments were obtained, including the liquid flow (m®) and the depth (m) measured with a level ruler. The measurements were made according to the width of the sampled section, ranging from 3–7 measurement points in the transversal direction per sampling point [3/s), the number of instantaneous speed measurements varied according to the depths found. Thus, following the methodology proposed by [To calculate the average flow of the channels in the cross sections, the instantaneous speed (m/s) was measured using a flow probe , measuring tape and a crosshair. Boards were built in the cross sections of the channels based on the slope data, for the monitoring of the seasonal variations. For the characterization of the contribution of the DA soil in the constitution of the DS sediment, soil samples from the DA area, from the bottom sediment of the channel bed and of the outcropping soil were collected. Sediment samples from the channel bed and soil from the banks were obtained every 50 m in the studied streams, totaling nine samples per stream. The DA soil was sampled in 23 equidistant points, distant about 300 m from the riverbed of the DS.2+) and magnesium (Mg2+) and exchangeable aluminum (Al3+), were benchmarked by Extractor: KCl -1 mol/L; potential acidity (H + Al) were benchmarked by Calcium Acetate Extractor 0.5 mol/L—pH 7.0. The exchangeable bases (SB) and organic matter (OM) were determined through C.Org x 1.724 -Walkley-Black.The samples of the sediment and soil (300g) were removed (first 20 cm depth) with the aid of a plastic shovel. In laboratory, the samples were dried in an oven at 40° C , and anaGeneralized linear models (GLM) were constructed to test whether there was a difference between the flow of RS and DS. The GLMs had flow variables as explanatory variables and streams and seasonal seasons of the study period as explanatory variables. A generalized linear model (GLM) was also used to test whether there was a significant difference between the average particle size of the sediments and the soils of the two streams. The GLM had the particle size as a response variable of the sediment and the soil and the streams as an explanatory variable. To determine the difference between the categories, a contrast analysis was performed.A principal component analysis (PCA) was carried out using the R “vegan” package , with da2 and 454.04 m2, respectively (+ (135.56 mg/dm3 in RS and 44.55 in DS) and P (5.63 mg/dm3 in RS and 0.90 mg/dm3 in DS). Concentrations of CA2+ were higher in DS sediments, due liming process in the DA. Sediments from RS tends to be richer in phosphorous (5.63 mg/dm3average) in relation to DS (0.90 mg/dm3), while organic matter contents of the sediments were similar in RS (0.50 dag/Kg) and in DS (0.74 dag/Kg). Slightly finer-grained sediment was dominant in RS (average 0.70 mm mean particle size soil) in relation to DS (0.48 mm mean particle size soil) (The Pedra Branca stream (degraded stream—DS) and the reference stream (RS) had similar regional geomorphological characteristics. The stretches had altimetry varying between 667 and 758 m (RS) and 618 and 715 m (DS), with average slopes of 9.1% (RS) and 9.7% (DS). The areas of its sub-basins are 334.12 mectively . Despiteze soil) .3/s) followed the precipitation patterns registered in the Catalão rainy season, being higher at the end of the rainy season  and calcium ions  and calcium ions (Ca2+). The DA soil still has a positive relationship with exchangeable aluminum (Al3+) and potential acidity  in relation to the chemical composition of the sediments of the streams and the soil of the degraded area (DA), showed a clear separation between the RS and DS sediments and a similarity between the DA soil and the sediment of DS. The first axis explains 49.37% of the variation, while the second axis explains 22.64%. RS presents a greater contribution of the element phosphorus (P) in its sediment and a negative relationship with potassium (K) and magnesium  cause a similar behavior of the net flow during the seasonal seasons. The great discrepancy between the two streams is in the use and occupation of their sub-basins. Despite presenting narrow riparian forests and both being inserted in an agro-pastoral region, the Pedra Branca (DS) stream has most of its headland located in the DA. This area, despite having been submitted to a restoration project, is deforested and with exposed soil (predominantly horizon C). As a consequence, the soil compaction in the area is much higher than the adjacent native forest areas , favorinThere is an intimate connection between lotic environments and rainfall –44. The Different hydrogeomorphological conditions were found in the reference (RS) and degraded (DS) streams. RS is in a more preserved condition, with high heterogeneity in the substrate of its bed. The DS is silted up over the entire length of the studied section, with a high level of substrate homogenization and with sediment bars, whose system energy during the rainy season was unable to remove ,46. ThesIt is interesting to note that the mean diameter of the sediment was significantly different between RS and DS. The DS presents much finer particles than those present in RS, with sizes similar to the remaining soil found in the DA by . This coRivers and small streams are among the natural resources that are most affected by environmental degradation processes ,54. ManyTo mitigate the scenario found in the Pedra Branca stream, it would be extremely urgent the restauration of the forest cover of the borrow pit area. With the restructuring of the vegetation cover and resulting restructuring of the soil, the erosion processes and the contribution of sediments to the stream bed would decrease. Another important short-term action would be the installation of sediment collectors in the drainage networks as well as their maintenance. Much of the rainwater is dumped into the Pedra Branca stream, as well as all the sediment transported by them. It would be necessary that these structures could trap part of the sediment transported avoiding the critical sedimentation of the Pedra Branca streambed.S1 Data(XLSX)Click here for additional data file.


Chitosan is a naturally occurring polysaccharide derived from chitin with a wide range of uses. Phthalocyanines are macroheterocyclic compounds that have a number of useful properties such as coloring and catalytic and antioxidant activity. Phthalocyanines are able to immobilize on chitosan, forming complexes with new useful properties. In this work, we evaluated the ability of phthalocyanines to increase the thermal stability of chitosan. Chitosan (CS) forms complexes with copper(II)-(CuPc) and cobalt(II)-(CoPc) tetrasulphophthalocyanines. The processes of destruction of chitosan (CS) and its complexes with sulphophthalocyanines CuPc and CoPc in oxidizing and inert atmospheres have been studied. It was established that, regardless of the atmosphere composition, the first chemical reactions taking place in the studied systems are elimination reactions. The latter ones in the case of chitosan and complex CS-CuPc lead to the formation of spatially crosslinked polymer structures, and it causes the release of CuPc from the polymer complex. It was found that in the case of CS-CoPc elimination reactions did not lead to the formation of crosslinked polymer structures but caused the destruction of the pyranose rings with a partial release of CoPc. Metallophthalocyanines showed antioxidant properties in the composition of complexes with chitosan, increasing the temperature of the beginning of glycosidic bond cleavage reaction by 30–35 °C in comparison with the similar characteristics for chitosan. Among the factors determining the stability of complexes of phthalocyanines with metal ions, the geometric correspondence of the covalent radius of the metal cation and the diameter of the reaction cavity of the macro ring are of great importance. They determine the efficiency of the formation of σ- and π-coordination bonds . For example, the diameter of the phthalocyanine reaction center is about 2.8 Å [Phthalocyanines are aromatic macroheterocyclic compounds capable of forming internal salts with almost all metals of the Periodic system. In this case, the aromatic phthalocyanine macrocycle is an equatorial ligand. Stable intracomplex of phthalocyanines salts with metal ions arises due to the formation of four equivalent σ -bonds N ->M  formed in the reaction between the superoxide anion and the yellow dye (NBT2+) [3+/ferricyanide complex to the ferrous form in the tested samples with reductants (antioxidants). The Fe2+ was then monitored by measuring the formation of Perl’s Prussian blue at 700 nm. Judging by numerous data [Recently, publications began to appear in the scientific literature that have reported on the diametrically opposite properties of MPc—their antioxidant ability ,20,21,22 (NBT2+) ; (3) accous data ,20,21,22Chitosan is one of the natural polymers that are currently being widely studied. Chitosan is a biodegradable polymer, and therefore it is very popular in terms of green chemistry . New matTherefore, the aim of this work was to study the effect of metal complexes of sulphosubstituted phthalocyanines on the process of thermal oxidative destruction of chitosan on air and compare the results obtained with destruction in an inert atmosphere. At the first stage of the work, it is necessary to obtain polymer complexes of chitosan with phthalocyanines. Due to the fact that the studied chitosan and phthalocyanines are water-soluble, the complexes were obtained by mixing solutions of chitosan and phthalocyanine and subsequent drying on air. The thermochemical study of chitosan was carried out using TG/DTG, c-DTA, and mass spectrometric analysis. The obtained new fundamental knowledge can be useful for future applications using chitosan-phthalocyanine complexes.−4; α = 0.885 [1H NMR spectroscopy described in [1 H NMR spectra were recorded with an Avance III (Bruker) NMR spectrometer (500.17 MHz) using a 2% DCl solution in D2O as solvent. The degree of deacetylation of the sample used in the work was 94%. pH of chitosan solution was 6.5.Herein we used chitosan hydrochloride  from cra = 0.885 . The degribed in . 1 H NMR−1.Copper(II)tetrasulphophthalocyanine and cobalt(II)tetrasulphophthalocyanine  were syn−5 M and 0.02 mass% of chitosan.Crystalline samples of polymer complexes of chitosan with metallophthalocyanines were obtained by evaporating solutions with a concentration of sulphophthalocyanines 6.4 × 10DMF with a purity greater than 99%, ethanol 98% and chloroform with a purity of 99.5% were used as received from Sigma Aldrich without further purification.UV-Vis spectra of solutions were registered using AvaSpec-2048 spectrophotometer , in 1 cm quartz cuvettes at 25 °C. AvaLight-DHS was used as light source.−1 in a dynamic atmosphere air with a gas flow rate of 30 mL·min−1 from room temperature to 600–700 °C. The accuracy of measuring the mass of the sample amounted 1 × 10−7 g. The supplied software allows the semi-quantitative determination of thermal effects using the c-DTA curve. c-DTA is the calculated differential thermal analysis (DTA) curve. The c-DTA signal is evaluated as the difference between the temperature-time curve with the test sample and the temperature-time curve without the sample (baseline with an empty crucible). Despite the low sensitivity of the c-DTA signal, compared to the DSC signal, it can be used to identify thermal effects in the process of thermal and thermooxidative decomposition of the samples [For thermogravimetric analysis a thermo-microbalance TG 209 F1  was used. Powdered samples (4–7 mg) were placed in platinum crucibles and heated at a rate of 10 °C·min samples .−1).Mass spectrometric analysis was carried out using a STA 409 CD thermoanalytical unit  equipped with a mass spectrometer with a QMG 422 skimmer system . This unit provided thermogravimetric and DSC measurements with simultaneous recording of mass spectra of the thermal decomposition products. The samples were heated at atmospheric pressure in a stream of dry ultrapure argon  at 150 °C for 1 h. The approach is rather interesting, but we failed to achieve 100% monomerization of MPc within this complex. Possible reasons are either a change in the conformation of the natural polymer in the DES medium (choline chloride: urea in a molar ratio of 2:1), or weak retention and migration of CuPc in the composition of the polymer. The only type of bond between synthesized copper(II) phthalocyanine and chitosan is a very weak donor—acceptor bond of the Cu←NH2 of chitosan group, if any. Cu2+ (3d9), in addition to the formation of σ-bonds with the phthalocyanine macrocycle, can form inverse native π-bonds of metal ion→phthalocyanine, and this leads to an extremely low coordination ability. In addition, the authors of [There are various approaches to obtaining chitosan complexes with phthalocyanines. For example, in , the abithors of  did not thors of ,34, with−5 M) has an electronic absorption spectrum typical of MPc in the monomeric state (namely the Q-band) is clearly resolved with a maximum at 667 nm and vibrational satellite at 599 nm (−5 M) in the initial solution is partially dimerized, since in addition to the absorption of the monomer (λ = 657 nm), absorption by dimeric structures (632 nm) is also recorded. The addition of chitosan to the phthalocyanine solution leads to an increase in the proportion of dimeric structures in both cases. The spectral changes  were determined from the TG/DTG curves and are presented in In As can be seen from The next stage after dehydration is the beginning of the process of thermooxidative degradation of the polymer and its complexes with MPc. The interpretation of the chemistry of the thermal oxidation process, in contrast to pyrolysis, is more complicated, since the use of an atmosphere of air excludes the possibility of recording mass spectra of gaseous products, and the analysis of the IR spectra of samples heated to certain temperatures is complicated due to the ambiguity of spectral changes. Therefore, it makes sense to establish the general and distinctive features of the destruction of CS, CoPc, CS-CoPc, CuPc and CS-CuPc in air obtained in this work and the thermal decomposition of the same samples in argon obtained in the previous work  Figure .2) to which the DTG curves in argon and air change symbatically coincide  . In this2 in the polymer will disorder the packaging of the polymer chains, and disrupt the network of hydrogen bonds between the aminogroups of neighboring macromolecules. The complexation of chitosan with CuPc prevents the occurrence of radical processes associated with the breaking of the glycosidic bond. Thus, CuPc in the composition of the polymer complex of CS-CuPc exhibits antioxidant properties.Thus, to summarize the observations, one can say that the complexation of chitosan with CuPc promotes the processes of deamination, deacetylation and dehydration, probably due to the facilitation of the removal of gaseous products, since large dimeric structures (CuPc)Judging by the TG curves , the desEvaluation of the solubility of the initial CS-CoPc complex and the one heated to a temperature of 225 °C in water, acidified water, chloroform, ethyl alcohol, and DMF showed that the dark blue polymer complex is highly soluble in water and insoluble in organic solvents. As in the case of the initial CS-CuPc complex, CS-CoPc not subject to heating is rather resistant to extraction, and only a partial transition of CoPc to DMF is detected . Heated 2+ ion in the phthalocyanine to additional coordination on the electron-donating atoms of the polymer , and the absence of spatially cross-linked polymer structures will not render steric hindrances for the implementation of the indicated donor-acceptor interaction.A lower degree of extraction of CoPc compared to CuPc is probably due to the ability of the CoThus, summarizing the data obtained, it can be concluded that the presence of CoPc in the polymer in an oxidizing and inert atmosphere has practically no effect on the temperature at the start of deamination, deacetylation and dehydration of the polymer, but unlike chitosan and CS-CuPc, these elimination reactions do not lead to the formation of crosslinked polymer structures, but cause a collapse of the structure of chitosan and destruction of the pyranose rings. CoPc effectively prevents the occurrence of free radical processes, inactivating randomly generated radicals and thereby breaking the chain.2 2 immobilized in the polymer contribute to the elimination reactions due to the better removal of volatile degradation products. The reactions of deamination, intermolecular dehydration, and accidental cleavage of glycosidic bonds lead to the formation of crosslinked polymer structures in the case of chitosan and CS-CuPc. In the latter case it results in the release of CuPc up to T = 225 °C.CoPc in the CSCoPc complex has a different effect on thermally induced reactions. The chemistry of the processes of destruction of CSCoPc in argon and air are similar up to a temperature of 342 °C. The destruction of CSCoPc, as well as CS, begins from the stage of cleavage of glycosidic bonds. Further, as for CS, the deamination and dehydration reactions of CSCoPc begin when 171 °C is reached. The monomeric and dimeric forms of CoPc immobilized in the polymer do not affect the temperature at which the elimination reactions begin, but at the same time they prevent the formation of crosslinked polymer structures and the release rate of CoPc remains low. It was found that the effect of both metallosulphophthalocyanines on the thermal oxidation of CS is manifested in an increase in the temperature of the onset of polymer-radical reactions by 30–35 °C, associated with the rupture of glycosidic bonds, and this fact can be considered as confirmation of our hypothesis about the antioxidant activity of phthalocyanines.The information obtained may be in demand in the development of technological processes for the preparation of immobilized catalysts, graphite-like structures and fibers during thermo- and thermo-oxidative action on polysaccharides.


We studied the effects of adding Y on the microstructure, mechanical properties and wear properties of ZCuSn10Pb10, and clarified the underlying mechanism by microstructure characterization through SEM, EDS and XRD. No new phase was detected after the addition of Y up to 0.2 wt.%, but an enrichment of Y in the Pb phase was found. The Pb particles were refined significantly after the addition of Y, which resulted from the compositional undercooling for the Cu dendrite where the Pb particles solidified, and the highest refinement efficiency was reached when the content of Y was 0.15 wt.%. The hardness of the alloy was improved due to the refinement of the microstructure. The fine Pb particles between the dendrite branches acted as solid lubricant, which was smeared on the entire surface during a friction and wear experiment, thus increasing wear resistance and reducing the coefficient of friction. Bronze is a copper-based alloy, with tin (Sn), lead (Pb) and zinc (Zn) as alloying elements . BronzesWear resistance and low coefficient of friction are some of the most important characteristics required for sliding bearings because one of the main mechanisms of wear is abrasive wear associated with sliding friction on the contact surface between the neck and the bushing. Without a lubrication film, direct contact between components can cause dry friction, which can lead to the wear and tear of bearings ,11.In lead-tin bronze, the microstructure consists of α-Cu solid solution, α-δ eutectoid ,12 and lThe addition of rare-earth elements can purify Cu melts and improve microstructure, thereby improving the mechanical and other physical and chemical properties of Cu . Adding Pure copper, pure zinc, pure lead, pure tin, pure nickel and copper-yttrium master alloy were used to prepare the Cu-10Sn-10Pb-1.75Zn-2Ni-xY (x = 0–0.2) . The pure copper and pure nickel were melted in a resistance furnace at 1150 °C, then the copper-yttrium alloy was added to the crucible, which was followed by pure zinc, pure lead and pure tin. The melt was then stirred with a graphite stick for composition homogenization. The melt with the temperature of 1150 °C was cast into a metal mold preheated to 250 °C, as shown in Tensile test specimens with the dimensions shown in The specimen for metallographic characterization was cut from the cast piece, as shown in Samples for the phase composition analysis with the dimensions of 15 mm × 10 mm × 10 mm were cut from the same place as those for microstructure analysis, as shown in #. The speed of low oil lubrication was 1500 r/min with a test force load of 250 N and test time of 120 min. Before the test, all specimens were treated with the same procedure to ensure identical surface condition for all specimens: they were ground by silicon carbide paper, polished and cleaned in the ultrasonic cleaner for 5 min. The friction and wear results were the average of three tests. The sample and steel ring were cleaned with acetone using an ultrasonic cleaner after the test, then the specimens were weighed with an electronic analytical balance. The weight was measured five times and the wear rate was calculated as follows:Φ, wear rate; m1, weight before wear experiment (g); m2, weight after wear experiment (g); ρ, density (g/cm3); F, test force (N); v, rotation speed (m/s); t, test time (s).The friction test was carried out on an MRH-3A type high-speed ring block wear test machine ; a schematic diagram of the friction and wear test mode is shown in The densities of the as-cast ZCuSn10Pb10 alloys were measured using the Archimedes method by immersing the samples in double-distilled water. The density of each alloy was the average of at least five measurements.There was no apparent change in the tensile strength of the ZCuSn10Pb10 alloy with increasing Y addition when the standard deviation of the experimental results were taken into account; as shown in To investigate the origin of the evolution of the mechanical properties and friction and wear properties of the alloy with increasing Y content, the microstructure of the alloys was studied. 2 and 51–150 µm2 first increased and then decreased as the Y content increased. The refinement effect of the lead particles can be rationalized by the refinement of the dendrite. The finer structure divided the lead-containing liquid into smaller compartments, which refined the lead particles. However, when the Y content reached 0.2%, the lead particles coarsened. This may have resulted from the more developed Cu dendritic structure; the long dendritic branches may have contacted with each other earlier during cooling and formed larger compartments for the Pb-containing liquid phase that solidified into larger Pb particles. With excessive addition of Y, the temperature for the solidification of the Pb particles might also change and result in coarser Pb particles [articles . HoweverThe SEM results in To study the phase composition of the alloys with different Y content and identify the Y-containing Pb-rich phase, the XRD analysis was carried out and the results are shown in The results above show that the effect of Y on the friction and wear properties depends on the microstructure evolution of the alloy with increasing Y addition. Both the hard matrix and the soft second phases evolved after adding Y. The refinement of the dendritic Cu structure and solution of Y strengthened the Cu matrix, leading to better load-bearing capacity. The addition of Y not only led to fine and homogeneously distributed Pb particles, but also reduced its strength, facilitating the formation of lead film during the friction and wear tests. All these changes in the microstructure help to preserve a good lubrication film on the interface. Since the refinement efficiency on both Cu dendrite and Pb particles peaked at a Y content of 0.15%, the ZCuSn10Pb10 alloy with 0.15% Y displayed the best friction and wear properties.The effects of adding Y on the microstructure, mechanical properties and friction and wear properties of the ZCuSn10Pb10 alloy were studied, and the influencing mechanism of the Y on the alloy was clarified. The following conclusions are drawn:Both the hardness and strength of the alloy first increased and then decreased with the increasing content Y, and the highest hardness and strength was reached when the content of Y was 0.15%.Y refined both the dendritic structure and lead particles of the alloy, and the addition of 0.15% Y showed the highest refinement efficiency of lead particles.No new phase formed after the addition of Y up to 0.2%. Y dissolved inside Pb, which increased the resistance of Pb to be worn off during the friction and wear test, and improved the friction and wear properties of the alloy.


Background: Since the novel coronavirus disease (COVID-19) has been a worldwide pandemic, the early surveillance and public health emergency disposal are considered crucial to curb this emerging infectious disease. However, studies of COVID-19 on this topic in China are relatively few.Methods: A case-comparison study was conducted using a set of six key time nodes to form a reference framework for evaluating early surveillance and public health emergency disposal between H7N9 avian influenza (2013) in Shanghai and COVID-19 in Wuhan, China.Findings: A report to the local Center for Disease Control and Prevention, China, for the first hospitalized patient was sent after 6 and 20 days for H7N9 avian influenza and COVID-19, respectively. In contrast, the pathogen was identified faster in the case of COVID-19 than in the case of H7N9 avian influenza (12 vs. 31 days). The government response to COVID-19 was 10 days later than that to avian influenza. The entire process of early surveillance and public health emergency disposal lasted 5 days longer in COVID-19 than in H7N9 avian influenza (46 vs. 41 days).Conclusions: The identification of the unknown pathogen improved in China between the outbreaks of avian influenza and COVID-19. The longer emergency disposal period in the case of COVID-19 could be attributed to the government's slower response to the epidemic. Improving public health emergency management could lessen the adverse social effects of emerging infectious diseases and public health crisis in the future. In the past 20 years, China has experienced several public health crises due to infectious disease outbreaks, such as severe acute respiratory syndrome in 2003, H1N1 swine influenza in 2009, and H7N9 avian influenza in 2013, seriously impacting health, economy, and global security , 5. In lCOVID-19 and H7N9 avian influenza are two emerging infectious diseases that share similar characteristics , such asIn this study, we aimed to conduct a retrospective study to compare the COVID-19 in Wuhan with the well-controlled H7N9 avian influenza (2013) in Shanghai, China, which should include the contents of the detection of the case, the initiation of emergency response, and etc. With the detailed comparison, the study would be able to summarize the lessons and propose measures to better improve the immediate responses to emergent public health events.http://en.nhc.gov.cn/), Chinese Center for Disease Control and Prevention (CDC) (http://www.chinacdc.cn/en/), Health Commission of Hubei Province, and Wuhan Municipal Health Commission], and credible media reports in China . Data regarding H7N9 avian influenza in Shanghai, China, were obtained from our published literature  scan and an abnormality in their son's CT scan as well. The next day, the hospital reported four abnormal CT findings to the local CDC including another case  in Shanghai and COVID-19 (2019) in Wuhan was 6 and 20 days, respectively.The local CDC conducted an epidemiological survey and sampling at 4:00 a.m. on February 26, 2013 and informed the hospital at 10:30 a.m. that adenovirus, syncytial virus, Legionella, H1N1, highly pathogenic avian influenza virus, Mycoplasma, and seasonal influenza virus tested negative. The hospital subsequently sent the samples to the P3 Laboratory of Shanghai Public Health Clinical Center. On March 22, the Shanghai Public Health Clinical Center preliminarily confirmed the pathogen as a new type of avian influenza virus. On March 29, 2013, the National CDC isolated a new type of avian influenza virus from samples collected from patients.The local CDC was unable to identify the pathogen on December 26, 2019 and subsequently sent the samples to various testing institutions, including Shanghai Public Health Clinical Center and the Chinese Academy of Sciences (Wuhan Virus Institute). Various testing institutions had identified the novel coronavirus and the complete genome sequence between December 30, 2019 and January 5, 2020 . On JanuHence, the time taken to identify the pathogen in the cases of H7N9 (2013) in Shanghai and COVID-19 (2019) in Wuhan was 31 and 12 days, respectively.On March 31, 2013, the National Health Administration confirmed that the pathogen was a new type of avian influenza virus. On April 2, 2013, the government of Shanghai launched a level-three response  to public health emergencies.On January 8, 2020, the National Health Administration confirmed that the pathogen was a novel coronavirus. On January 22, 2020, the government of Hubei Province launched a level-two response  to public health emergencies .Hence, the time taken by the government to respond in the cases of H7N9 (2013) in Shanghai and COVID-19 (2019) in Wuhan City was 4 and 14 days, respectively.We compared the government's emergency response process between outbreaks of Shanghai H7N9 avian influenza in 2013 and Wuhan COVID-19 in 2019. The time taken from the detection of the first case to the implementation of public health emergency response was 41 and 46 days for H7N9 avian influenza and COVID-19, respectively. The hospital to CDC reporting period was 14 days slower in the case of COVID-19 than in the case of H7N9 avian influenza. The time taken to identify the pathogen was 19 days faster in the case of COVID-19 than in the case of H7N9 avian influenza. Lastly, the time taken by the government to respond was 10 days slower in the case of COVID-19 than in the case of H7N9 avian influenza .To the best of our knowledge, this was one of the few studies conducted in China to compare the strengths and weaknesses of public health emergency disposal between COVID-19 and H7N9 avian influenza. In this case-comparative study, the time taken to detect unknown pathogens had improved between the outbreaks of H7N9 avian influenza and COVID-19, whereas the time taken for hospitals to report a case to the local CDC and the government's emergency response was significantly increased.In this study, we mainly investigated three crucial periods that influence the efficiency of emergency management of public health crises. During the emergency response process for H7N9 avian influenza (2013) in Shanghai, the maximum time was taken to technically identify and recheck the pathogen. The technical identification of pathogen took 24 days and the rechecking took 7 days, which accounted for 76% of the whole emergency process. In contrast, the time taken to technically identify and recheck the pathogen in the case of COVID-19 was reduced to just 12 days, accounting for 24% of the whole emergency process.Laboratory identification was 19 days faster in the case of COVID-19 than in the case of H7N9 avian influenza, whereas the total disposal time was 5 days longer in the case of COVID-19 than in the case of H7N9 avian influenza. This could be attributed to the decrease in the reporting periods of certain hospitals and the increase in responding periods of the local governments. The time taken by the hospital to report a case to the local CDC was 14 days longer during COVID-19 than during H7N9 avian influenza . Furthermore, the response period of the local government launching emergency management was 14 days during COVID-19, which was 10 days longer than that during H7N9 avian influenza. Combining the hospital to CDC reporting period and government response period of H7N9 avian influenza with the pathogen identification period of COVID-19 would result in the entire epidemic control taking <22 days. Moreover, Hubei Province could thus launch an emergency response on December 30, suggesting that approximately 27 cases of COVID-19 would be detected in Hubei Province and the number of close contacts would be approximately 1350 by early March 2020. The Wuhan Municipal Infectious Diseases Hospital alone had 350 beds, which was sufficient to handle the full admission. Subsequently, the local CDC also had sufficient capabilities to screen and isolate most of the patients in close contacts with the infected patients.The 5-day longer emergency period during COVID-19 could possibly be attributed to the hospital to CDC reporting period and government response period constrained by the following objective conditions: (1) At the beginning stage of the epidemic, H7N9 appeared a larger threat. The interval between the first identified case and the first reported death was only 7 days . For COVID-19, this interval was 32 days instead. On January 9, local medical institutions and disease control departments were instructed to speed up and implement isolation and precautionary measures  in 2009 respectively. The study found that the emergency response time of the COVID-19 epidemic (46 days) was 18 days longer than that of H1N1 (28 days). The speed of hospital reporting, pathogen identification, and government decision-making of COVID-19 were all slower than those during HIN1 in particular. In the ongoing progress of the epidemic, the peak onset of H1N1 was about 4 weeks later than COVID-19, and the epidemic curve of H1N1 was flatter, which might be related to the timely emergency response of the HIN1 epidemic. The other study which compared the emergency response time between the SARS epidemic (127 days) and COVID-19, found that the latter was 81 days shorter. The hospital report time of these two epidemics was similar, but the pathogen detection time of SARS was more than 3 months longer than that of COVID-19, which reflected the level of pathogen detection in China has been greatly improved these years. After then, in following research, we will summarize the correlation between disposal time in different epidemics and their spread speed, attempt to explore the standard of emergency response procedures and their time constraints, so as to provide a reference for public health emergency response in the future.This study has several potential limitations. First, the assessment coverage was at the city level; thus, comparison between the national level and the grassroots level was not assessed in this study. The grassroots level is the first gateway of public health emergency, and the effective measures and emergency responses taken by the grassroot level are considered important. Second, we used six-time nodes to evaluate the process of the government's emergency response, which is relatively limited when evaluating the possibility of an epidemic of major infectious diseases. Third, the data were based on China's official and authoritative reports, coupled with retrospective studies, which inevitably had information bias. Considering all these limitations, the findings should be interpreted with caution before additional studies are conducted.The identification of the unknown pathogen has significantly improved in China between the outbreaks of H7N9 avian influenza and COVID-19. However, the speed of the hospital reporting an emerging infectious disease and the speed of the government decision-making were slow in COVID-19 epidemic, which might be one of the vital factors for widespread COVID-19 cases. These issues need to be addressed urgently to prepare for public emergencies to prevent and control future epidemics of emerging infectious diseases in China and the world.The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding author/s.TZ, QW, and LL designed the project, processed and analyzed the data, and wrote the manuscript. YW, GB, and RD edited the manuscript. All authors revised the draft.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. 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