Complete kinetic model for esterification reaction of lauric acid with glycerol to synthesize glycerol monolaurate

Glycerol monolaurate(GML)is a widely used industrial chemical with excellent emulsification and antibacterial effect.The direct esterification of glycerol with lauric acid is the main method to synthesize GML.In this work,the kinetic process of direct esterification was systematically studied using p-toluenesulfonic acid as catalyst.A complete kinetic model of consecutive esterification reaction has been established,and the kinetic equation of acid catalysis was deduced.The isomerization reactions of GML and glycerol dilaurate were investigated.It was found that the reaction was an equilibrium reaction and the reaction rate was faster than the esterification reaction.The kinetic equations of the consecutive esterification reaction were obtained by experiments as k_(1)=(276+92261Xcat)exp(-37720/RT)and k_(2)=(80+4413Xcat)exp(-32240/RT).The kinetic results are beneficial to the optimization of operating conditions and reactor design in GML production process.

Tannins from Canarium album with potent antioxidant activity

The contents of total phenolics and extractable condensed tannins in the leaves, twigs and stem bark of Canarium album were determined. The structural heterogeneity of condensed tannins from stem bark was characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry （MALDI-TOF MS） and nuclear magnetic resonance （NMR） analyses The results show the predominance of signals representative of procyanidins and prodelphinidins. In addition, epicatechin and epigallocatechin polymers with galloylated procyanidin or prodelphinidin were also observed. The tannins were screened for their potential antioxidant activities using l,l-diphenyl-2-picrylhydrazyl （DPPH） and ferric reducing/antioxidant power （FRAP） model systems. Tannins extracted from leaves, twigs and stem bark all showed a very good DPPH radical scavenging activity and ferric reducing power.

Geology and mineralization of the Sanshandao supergiant gold deposit(1200 t)in the Jiaodong Peninsula,China:A review

The Jiaodong Peninsula in Shandong Province,China is the world’s third-largest gold metallogenic area,with cumulative proven gold resources exceeding 5000 t.Over the past few years,breakthroughs have been made in deep prospecting at a depth of 500‒2000 m,particularly in the Sanshandao area where a huge deep gold orebody was identified.Based on previous studies and the latest prospecting progress achieved by the project team of this study,the following results are summarized.(1)3D geological modeling results based on deep drilling core data reveal that the Sanshandao gold orefield,which was previously considered to consist of several independent deposits,is a supergiant deposit with gold resources of more than 1200 t(including 470 t under the sea area).The length of the major orebody is nearly 8 km,with a greatest depth of 2312 m below sea level and a maximum length of more than 3 km along their dip direction.(2)Thick gold orebodies in the Sanshandao gold deposit mainly occur in the specific sections of the ore-controlling fault where the fault plane changes from steeply to gently inclined,forming a stepped metallogenic model from shallow to deep level.The reason for this strong structural control on mineralization forms is that when ore-forming fluids migrated along faults,the pressure of fluids greatly fluctuated in fault sections where the fault dip angle changed.Since the solubility of gold in the ore-forming fluid is sensitive to fluid pressure,these sections along the fault plane serve as the target areas for deep prospecting.(3)Thermal uplifting-extensional structures provide thermodynamic conditions,migration pathways,and deposition spaces for gold mineralization.Meanwhile,the changes in mantle properties induced the transformation of the geochemical properties of the lower crust and magmatic rocks.This further led to the reactivation of ore-forming elements,which provided rich materials for gold mineralization.(4)It can be concluded from previous research results that the gold mineralization in the Jiaodong gold deposits occurred at about 120 Ma,which was superimposed by nonferrous metals mineralization at 118‒111 Ma.The fluids were dominated by primary mantle water or magmatic water.Metamorphic water occurred in the early stage of the gold mineralization,while the fluid composition was dominated by meteoric water in the late stage.The S,Pb,and Sr isotopic compositions of the ores are similar to those of ore-hosting rocks,indicating that the ore-forming materials mainly derive from crustal materials,with the minor addition of mantle-derived materials.The gold deposits in the Jiaodong Peninsula were formed in an extensional tectonic environment during the transformation of the physical and chemical properties of the lithospheric mantle,which is different from typical orogenic gold deposits.Thus,it is proposed that they are named“Jiaodong-type”gold deposits.

Geology and mineralization of the Dayin’gezhuang supergiant gold deposit(180 t)in the Jiaodong Peninsula,China:A review

The Dayin’gezhuang gold deposit is located in the central part of the Zhaoping Fault metallogenic belt in the Jiaodong gold province-the world’s third-largest gold metallogenic area.It is a typical successful case of prospecting at a depth of 500-2000 m in recent years,with cumulative proven gold resources exceeding 180 t.The main orebodies(No.1 and No.2 orebody)generally have a pitch direction of NNE and a plunge direction of NEE.As the ore-controlling fault,the Zhaoping Fault is a shovel-shaped stepped fault,with its dip angle presenting stepped high-to-low transitions at the elevation of -2000-0 m.The gold mineralization enrichment area is mainly distributed in the step parts where the fault plane changes from steeply to gently,forming a stepped metallogenic pattern from shallow to deep.It can be concluded from previous studies that the gold mineralization of the Dayin’gezhuang gold deposit occurred at about 120 Ma.The ore-forming fluids were H_(2)O-CO_(2)-NaCl-type hydrothermal solutions with a medium-low temperature and medium-low salinity.The H-O isotopic characteristics indicate that the fluids in the early ore-forming stage were possibly magmatic water or mantle water and that meteoric water gradually entered the ore-forming fluids in the late ore-forming stage.The S and Pb isotopes indicate that the ore-forming materials mainly originate from the lower crust and contain a small quantity of mantle-derived components.The comprehensive analysis shows that the Dayin’gezhuang gold deposit was formed by thermal uplifting-extensional tectonism.The strong crust-mantle interactions,large-scale magmatism,and the material exchange arising from the transformation from adakitic granites to arc granites and from the ancient lower crust to the juvenile lower crust during the Early Cretaceous provided abundant fluids and material sources for mineralization.Moreover,the detachment faults formed by the rapid magmatic uplift and the extensional tectonism created favorable temperature and pressure conditions and space for fluid accumulation and gold precipitation and mineralization.

Computational fluid dynamic simulation of gas-liquid flow in rotating packed bed:A review

The rotating packed bed(RPB)has been widely used in gas-liquid flow systems as a process intensification device,exhibiting excellent mass transfer enhancement characteristics.However,the complex internal structure and the high-speed rotation of the rotor in RPB bring significant challenges to study the intensification mechanism by experiment methods.In the past two decades,Computational fluid dynamics(CFD)has been gradually applied to simulate the hydrodynamics and mass transfer characteristics in RPB and instruct the reactor design.This article covers the development of the CFD simulation of gasliquid flow in RPB.Firstly,the improvement of the simulation method in the aspect of mathematical models,geometric models,and solving methods is introduced.Secondly,new progress of CFD simulation about hydrodynamic and mass transfer characteristics in RPB is reviewed,including pressure drop,velocity distribution,flow pattern,and concentration distribution,etc.Some new phenomena such as the end effect area with the maximum turbulent have been revealed by this works.In addition,the exploration of developing new reactor structures by CFD simulation is introduced and it is proved that such new structures are competitive to different applications.The defects of current research and future development directions are also discussed at last.

High-gravity-assisted engineering of Ni_(2)P/g-C_(3)N_(4) nanocomposites with enhanced photocatalytic performance

Graphitic carbon nitride(g-C_(3)N_(4)) with transition metal phosphides has been studied extensively as potential photocatalysts for hydrogen evolution.However,in-situ approaches to realize intimate interfacial contacts have rarely been reported.In this study,Ni_(2)P nanoparticlesdecorated g-C_(3)N_(4)photocatalysts were prepared via liquid exfoliation of g-C_(3)N_(4) followed by in-situ loading of Ni_(2)P nanoparticles in a rotating packed bed(RPB) reactor.The optimized Ni_(2)P/g-C_(3)N_(4) exhibits high performance in visible-light-driven(λ > 420 nm) hydrogen evolution(~561 μmol g-1h-1),which is 103 times higher than that of pristine g-C_(3)N_(4).The superior photocatalytic performance and durability originate from the robust interfacial structure.Therefore,a Z-scheme route with enhanced transfer of photoinduced electron was proposed,and Ni_(2)P/gC_(3)N_(4) composites with smaller bandgaps than those of g-C_(3)N_(4) were realized.Due to the intensified mass transfer and mixing of RPB reactor,the adsorption and nucleation processes of Ni_(2)P on g-C_(3)N_(4) were enhanced,enabling scalable solar light-driven H_(2) production.

Isolated pancreatic injury caused by abdominal massage:A case report

BACKGROUND Regular abdominal massage can be used to treat digestive symptoms such as bloating and constipation and is reported to reduce abdominal discomfort,improve digestive function,and increase the quality of life,without serious adverse effects.Isolated pancreatic injury is rare,and most often occurs during severe trauma such as steering wheel impact injury.To our knowledge,pancreatic injury caused by massage has not yet been reported in the literature.CASE SUMMARY A 57-year-old woman was referred to our hospital for acute abdominal pain and transient syncope.On examination,she had low hemoglobin concentration and a high white blood cell count and neutrophil percentage.Plain computed tomography of the abdomen revealed a substantial hemorrhage in the abdominal cavity.A large amount of exudate in the pancreatic area was considered a hematoma.Preoperative diagnosis was difficult.Her hemoglobin and blood pressure did not rise even after blood.We suspected progressive bleeding in the abdominal cavity and urgently performed exploratory laparotomy.During the operation,the pancreas was confirmed to be ruptured;hence,spleen-preserving pancreatic body and tail resection were performed.A pancreatic fistula was found on the 15th d after the operation,and the patient was discharged with a drainage tube on the 24th d after active treatment.Subsequently,it was discovered that the patient had undergone a vigorous abdominal massage the day before the abdominal pain began.To our knowledge,this is the first report of isolated pancreatic injury and massive abdominal hemorrhage caused by abdominal massage.CONCLUSION Our findings indicate that any action that increases intra-abdominal pressure may cause internal organ damage.We also review similar cases reported in the literature.

Excitation-wavelength-dependent THz wave modulation via external bias electric field

A theoretical model was proposed to describe the effects of external bias electric field on terahertz(THz)generated in air plasma.The model predicted that for a plasma in a bias electric field,the amplification effect of the THz wave intensity increases with the increase of the excitation laser wavelength.We experimentally observed the relationship between the THz enhancement effect and the electric field strength at different wavelengths.Experimental results showed a good agreement with the model predictions.These results enhance our understanding of the physical mechanism by which femtosecond lasers excite air to generate THz and extend the practical applications of THz generation and modulation.

Chemical probe systems for assessing liquid–liquid mixing efficiencies of reactors

Liquid-liquid mixing,including homogeneous and heterogeneous mixing,widely exists in the chemical industry.How to quantitatively characterize the mixing performance is important for reactor assessment and development.As a convenient and direct method for mixing characterization,the chemical probe method uses some special test reactions to characterize the mixing results.Here,the working principle and selection requirements of this method are introduced,and some common chemical probe systems for homogeneous and heterogeneous mixing processes are reviewed.The characteristics and applications of these systems are illustrated.Finally,the development of the new system is proposed.

First records of Triatoma rubrofasciata(De Geer,1773)(Hemiptera,Reduviidae)in Foshan,Guangdong Province,Southern China

Background:Triatomines,also known as kissing bugs,which are found throughout the world and especially in Latin America,are well known natural vectors that transmit American trypanosomiasis,also called Chagas disease.In China,the presence of two species of Triatoma(Triatoma rubrofasciata and T.sinica)was recorded in the past.Due to the growing population and the increasing risk of the global spread of Chagas disease,triatomines became a potential public health nuisance,and in 2016,we started monitoring triatomine activities in southern China.Methods:Triatomine specimens were collected by the National Institute of Parasitic Diseases,Chinese Center for Disease Control and Prevention,and identified by their morphological characteristics under a dissecting microscope.In addition to morphological analysis,the genomic DNA of the specimens was extracted,and the mitochondrial 16S rRNA,the cytochrome b(CytB)gene and the nuclear ribosomal 28S rRNA gene were PCRamplified to analyze and confirm the species genetically.Results:One female adult insect and one male adult insect were collected in a dwelling in the rural area of Shunde County,Foshan City,Guangdong Province,China(22°42′44.63″N,113°08′45.34″E).The results from the morphological and genetic analyses indicated that these triatomines were T.rubrofasciata.Conclusions:This is the first time that the occurrence of T.rubrofasciata has been confirmed in Foshan City,Guangdong Province in southern China.Further studies are needed to reach a clearer understanding of the ecology of this species of triatomine,since it has been found to be naturally infected by Trypanosoma cruzi and T.conorhini and there is evidence of its domiciliation capabilities.

Weakened maize phenological response to climate warming in China over 1981‒2018 due to cultivar shifts

Assessing climate change impacts on crop phenology is essential for developing adaptation options.To better understand crop response and adaptation to climate change,there is an urgent need to investigate whether the impacts weakens and how crops responds to recent climate warming,as well as the roles of different drivers in crop phenology change.Here,we analyzed the spatiotemporal changes in maize phenology and the underlying mechanisms over 1981–2018 using up-to-date 6106 phenological observations at 327 agro-meteorological stations in China.We found that during 1981–2018 maize sowing and maturity dates were generally delayed by 0.6 and 1.2 d per decade,respectively,whereas heading date was advanced by 0.9 d per decade.Maize phenology was most negatively correlated with rising minimum temperature(night-time warming),followed by maximum(daytime)temperature,and least by mean temperature.The trends in maize phenology and the correlation between growth periods and temperature generally declined from 1981 to 1999 to 2000–2018 for both spring and summer maize,although climate warming during growth period did not slow down.The phenological response to temperature weakened mainly owing to agricultural managements,especially cultivar shifts.Climate change shortened growth period by 3.4 and 1.7 d per decade but cultivar shifts prolonged it by 4.5 and 2.1 d per decade for spring and summer maize,respectively.Our study highlights that maize phenology is more sensitive to night-time warming than daytime warming,and cultivar shifts far outweigh climate change.These findings foster the understanding of spatiotemporal dynamics of maize phenology and its drivers,which can benefit to develop effective climate change adaptation options for different regions.

Improvement in the weldability of molybdenum alloy by pre-welding solid carburising

Molybdenum(Mo), with its high chemical stability and resistance to neutron irradiation, has wide application prospects in the nuclear industry;however, the embrittlement of welded Mo joints limits its further application. In this study, the brittleness of the welded joints of Mo alloy was reduced and their strength was enhanced by adding carbon to the fusion zone(FZ) during laser welding. In the FZ of the Mo joints, carbon mainly existed as Mo_(2)C, and some free C atoms, and MoC and MoOxC yphases were also present. The distribution of Mo_(2)C directly influenced the bonding strength of the grain boundaries.As Mo_(2)C was dispersedly distributed as particles or discontinuous lines at the grain boundaries of Mo,it improved the resistance of the grain boundaries to the propagation of cracks and thereby increasing their strength. However, the Mo_(2)C phases distributed in a reticular pattern at the grain boundaries of Mo provided channels that enabled cracks to rapidly propagate, thereby reducing the resistance of the grain boundaries to crack propagation and weakening their strength. The emergence of the MoOxC yphase reduced the weakening effect of free oxygen atoms on the strength of grain boundaries of Mo.