The study aims to investigate the carbonated water erosion mechanism of lining concrete in tunnels traversing karst environment and enhance its resistance.In this study,dynamic carbonated water erosion was simulated t...The study aims to investigate the carbonated water erosion mechanism of lining concrete in tunnels traversing karst environment and enhance its resistance.In this study,dynamic carbonated water erosion was simulated to assess erosion depth,microstructure,phase migrations,and pore structure in various tunnel lining cement-based materials.Additionally,Ca^(2+)leaching was analyzed,and impact of Ca/Si molar ratio in hydration products on erosion resistance was discussed by thermodynamic calculations.The results indicate that carbonated water erosion caused rough and porous surface on specimens,with reduced portlandite and CaCO_(3) content,increased porosity,and an enlargement of pore size.The thermodynamic calculations indicate that the erosion is spontaneous,driven by physical dissolution and chemical reactions dominated by Gibbs free energy.And the erosion reactions proceed more spontaneously and extensively when Ca/Si molar ratio in hydration products was higher.Therefore,cement-based materials with higher portlandite content exhibit weaker erosion resistance.Model-building concrete,with C-S-H gel and portlandite as primary hydration products,has greater erosion susceptibility than shotcrete with ettringite as main hydration product.Moreover,adding silicon-rich mineral admixtures can enhance the erosion resistance.This research offers theory and tech insights to boost cement-based material resistance against carbonated water erosion in karst tunnel engineering.展开更多
A slurry-phase carbonation technique was utilized,employing argon oxygen decarburization slag(AOD slag)as a source of calcium and MgCl_(2) as a regulator for the crystal morphology of acicular aragonite.Subsequently,t...A slurry-phase carbonation technique was utilized,employing argon oxygen decarburization slag(AOD slag)as a source of calcium and MgCl_(2) as a regulator for the crystal morphology of acicular aragonite.Subsequently,the carbonated AOD slag,enriched with acicular aragonite,was employed in fabricating composite cementitious materials,followed by an analysis of their evolution in hydration heat,hydration products,and microscopic morphology.Additionally,it delved into the mechanism through which acicular aragonite enhances the stength of composite cementitious materials.Moreover,advanced simulation software for engineering and sciences(ABAQUS)was utilized to simulate the compressive performance of composite mortar with varying dosages of acicular aragonite.The findings demonstrate that the carbonated AOD slag,containing 83.4%acicular aragonite(with an average aspect ratio of 21.31),exhibited commendable compatibility with cement.Moderate integration of carbonated AOD slag facilitated the formation of calcium sulfoaluminate hydrate(AFt)phases.The acicular aragonite within the cementitious matrix showcased remarkable filling effects.As the dosage of carbonated AOD slag increased,flexural and compressive strengths of cement mortar initially rose before declining.Upon reaching a 6%cement inclusion of carbonated AOD slag,the various constituents of the cementitious material displayed optimal synergy.The numerical simulation results confirmed the experimental findings,demonstrating a favorable increase in compressive strength and flexural strength with the addition of acicular aragonite.The acicular aragonite strengthened the matrix by serving bridging and pull-out functions.展开更多
The crevice corrosion of the reinforcing steel in the carbonated simulated concrete pore solutions(SCPSs)containing 0.04 mol/L chloride was investigated.In comparison,the steel without crevice covered on its surface w...The crevice corrosion of the reinforcing steel in the carbonated simulated concrete pore solutions(SCPSs)containing 0.04 mol/L chloride was investigated.In comparison,the steel without crevice covered on its surface was also studied.Results showed that the crevice corrosion in the uncarbonated SCPS was not triggered and the steel remained passivity by suppressing the anodic dissolution in the crevice interior.As SCPS was carbonated to have pH values of 10.5 and 11.5,the crevice corrosion was easier to be activated than the widely reported pitting corrosion owing to the rapid oxygen depletion within the crevice,but the crevice corrosion damage might be alleviated to a certain extent due to the relative compact surface film formed inside the crevice.The further carbonation led to the activation dissolution of both the crevice interior and exterior,causing the more serious corrosion damage.Corrosion process of the crevice corrosion was systematically analyzed by combining the electrochemical measurement results and Evens polarization diagram.展开更多
Due to the limited hydration capacity,solidification/stabilization(S/S)with waste concrete powder(WCP)has a low strength.Carbonation can reduce carbon dioxide(CO_(2))emissions and improve strength of lead-contaminated...Due to the limited hydration capacity,solidification/stabilization(S/S)with waste concrete powder(WCP)has a low strength.Carbonation can reduce carbon dioxide(CO_(2))emissions and improve strength of lead-contaminated soil,but its mechanism and environmental behaviors are unclear.In light of this,a comprehensive study was conducted on the compressive strength,lead immobilization,conductivity characteristics,and carbonation mechanism of carbonated Pb-contaminated soils stabilized with WCP compared to calcining 600℃WCP.Results indicated that with carbonation,the compressive strength of the samples was significantly improved at the early stage(1 d),resulting in increased unconfined compressive strength(UCS)by 2.5-5.2 times due to the filling of pores by calcite.It negatively affected the lead immobilization capacity of highly doped(30%)samples,while this effect reversed after 3 d of carbonating due to the reduced alkaline environment.The lead immobilization capacity decreased after 28 d of carbonating due to the cracking of samples and the influence of a lower pH on the solubility of lead-carbonated hydroxide((PbCO_(3))_(2)Pb(OH)_(2)).The water evaporation(saturation<16.8%)led to dry shrinkage cracking and decreased UCS of the samples.Based on this finding,a conductivity model was developed for carbonated and cured samples,accurately predicting changes in saturation levels(R^(2)=0.98).A relationship between conductivity and UCS or lead immobilization capacity was proposed.This research proposed an innovative method for the reduction of CO_(2)emission as well as laid down a theoretical basis for the recovery of WCP and lead-contaminated soils through carbonation.展开更多
BACKGROUND The clinical effectiveness of magnetically controlled capsule endoscopy(MCE)is well established.However,problems,such as abdominal distension,insufficient gastric filling,and prolonged gastric retention tim...BACKGROUND The clinical effectiveness of magnetically controlled capsule endoscopy(MCE)is well established.However,problems,such as abdominal distension,insufficient gastric filling,and prolonged gastric retention time,persist with MCE gastric preparations.AIM To compare gastric filling using a carbonated soft drink with that using pure water during MCE.METHODS We performed an open-label randomised controlled trial at the Endoscopy Centre of Changhai Hospital in Shanghai.Patients aged 18-80 years,with or without gastrointestinal symptoms,scheduled for MCE were consecutively recruited.Those who provided informed consent were randomly assigned to the carbonated soft drink group(C group)or water group(W group)in a 1:1 ratio.For patients in the W group,1000 mL of water was ingested to distend the stomach,whereas for patients in the C group,550 mL of carbonated soft drink was provided,and patients were required to drink quickly while minimising burping.The primary endpoint was the number of patients with a gastric filling score of≥4 within 5 minutes after the capsule entered the stomach.RESULTS From December 3,2020 to May 17,2021,252 patients(141 men),aged 18-77 years,were assigned to the C(n=126)and W(n=126)groups.For the primary outcome,123 patients in the C group achieved a gastric filling score of≥4(97.62%vs 80.16%,P<0.0001).More patients in the C group had the highest gastric filling scores within the first 5 min(78.57%vs 29.37%,P<0.0001)and 10 minutes(54.76%vs 13.49%,P<0.0001)after the capsule entered the stomach.More patients in the W group required extra liquid for gastric refilling(1.59%vs 16.67%,P<0.0001).Transpyloric passage of the capsule under magnetic control was successfully performed in 43 patients in the C group(P<0.0001),accompanied by a shorter gastric transit time(53.27±53.83 minutes vs 71.12±52.19 minutes,P=0.001).CONCLUSION Carbonated soft drinks demonstrated superior and more sustained gastric filling compared with those of water alone,with the potential to promote gastric emptying.展开更多
The presence of heavy metals in soil negatively impacts its mechanical properties.Reactive MgO carbonation presents a promising approach to enhance the solidification of Pb-contaminated sandy soils.However,the mechani...The presence of heavy metals in soil negatively impacts its mechanical properties.Reactive MgO carbonation presents a promising approach to enhance the solidification of Pb-contaminated sandy soils.However,the mechanical properties and structural behavior of contaminated soils during carbonation can vary significantly due to differences in soil composition.This study examines the potential application and underlying mechanisms of reactive MgO carbonation in improving the mechanical properties of Pb-contaminated red clay.The findings demonstrate that Pb-contaminated red clay transitions from a plastic to a brittle state following reactive MgO carbonation.After 1 h of treatment,the strength of the red clay exceeded 3 MPa,even at high Pb^(2+)concentrations.The deformation modulus to unconfined compressive strength(UCS)ratio was calculated to be 37.761,with the failure strain primarily ranging from 1.5%to 4.0%.A strength prediction model for the reactive MgO-stabilized Pb-contaminated red clay was proposed,which showed good predictive accuracy.Furthermore,reactive MgO carbonation significantly reduced the Pb leaching concentration in the high-level Pb-contaminated soil to below 0.1 mg/L.Microscopic analysis revealed that an optimal amount of hydrated magnesium carbonates(HMCs)formed a stable and compact structure with the soil particles.However,long-term carbonation causes red clay particles to become sandy,and excessive HMCs can harm the soil structure.Therefore,to maximize the strength improvement while avoiding structural damage,the carbonation time should be controlled to 1 h.展开更多
Carbonated water injection(CWI)is a promising enhanced oil recovery(EOR)technology that has received much attention in co-optimizing CO_(2) storage and oil recovery.This study provides a comprehensive review of the fl...Carbonated water injection(CWI)is a promising enhanced oil recovery(EOR)technology that has received much attention in co-optimizing CO_(2) storage and oil recovery.This study provides a comprehensive review of the fluid system properties and the underlying changes in rock-fluid interactions that drive the CWI-EOR mechanisms.Previous research has indicated that CWI can enhance oil recovery by shifting reservoir wettability towards a more water-wet state and reducing interfacial tension(IFT).However,this study reveals that there is still room for discussion in this area.Notably,the potential of CWI to alter reservoir permeability has not yet been explored.The varying operational conditions of the CWI process,namely temperature,pressure,injection rate,salinity,and ionic composition,lead to different levels of oil recovery factors.Herein,we aim to meticulously analyze their impact on oil recovery performance and outline the optimal operational conditions.Pressure,for instance,positively influences oil recovery rate and CWI efficiency.On one hand,higher operating pressures enhance the effectiveness of CW due to increased CO_(2)solubility.On the other hand,gas exsolution events in depleted reservoirs provide additional energy for oil movement along gas growth pathways.However,CWI at high carbonation levels does not offer significant benefits over lower carbonation levels.Additionally,lower temperatures and injection rates correlate with higher recovery rates.Further optimization of solution chemistry is necessary to determine the maximum recovery rates under optimal conditions.Moreover,this review comprehensively covers laboratory experiments,numerical simulations,and field applications involving the CWI process.However,challenges such as pipeline corrosion,potential reservoir damage,and produced water treatment impact the further application of CWI in EOR technologies.These issues can affect the expected oil recovery rates,thereby reducing the economic returns of EOR projects.Finally,this review introduces current research trends and future development prospects based on recently published studies in the field of CWI.The conclusions of this study aid readers in better understanding the latest advancements in CWI technology and the strengths and limitations of the techniques used,providing directions for further development and application of CWI.展开更多
Carbonated recycled powder as cementitious auxiliary material can reduce carbon emissions and realize high-quality recycling of recycled concrete.In this paper,microscopic property of recycled powder with three carbon...Carbonated recycled powder as cementitious auxiliary material can reduce carbon emissions and realize high-quality recycling of recycled concrete.In this paper,microscopic property of recycled powder with three carbonation methods was tested through XRD and SEM,the mechanical property and microstructure of recycled powder mortar with three replacement rates were studied by ISO method and SEM,and the strengthening mechanism was analyzed.The results showed that the mechanical property of recycled powder mortar decreased with the increasing of replacement rate.It is suggested that the replacement rate of recycled powder should not exceed 20%.The strength index and activity index of carbonated recycled powder mortar were improved,in which the flexural strength was increased by 27.85%and compressive strength was increased by 20%at the maximum.Recycled powder can be quickly and completely carbonated,and the improvement effect of CH pre-soaking carbonation was the best.The activity index of carbonated recycled powder can meet the requirements of Grade II technical standard for recycled powder.Microscopic results revealed the activation mechanism of carbonated recycled powder such as surplus calcium source effect,alkaline polycondensation effect and carbonation enhancement effect.展开更多
Carbonated water injection(CWI)is known as an efficient technique for both CO2 storage and enhanced oil recovery(EOR).During CWI process,CO2 moves from the water phase into the oil phase and results in oil swelling.Th...Carbonated water injection(CWI)is known as an efficient technique for both CO2 storage and enhanced oil recovery(EOR).During CWI process,CO2 moves from the water phase into the oil phase and results in oil swelling.This mechanism is considered as a reason for EOR.Viscous fingering leading to early breakthrough and leaving a large proportion of reservoir un-swept is known as an unfavorable phenomenon during flooding trials.Generally,instability at the interface due to disturbances in porous medium promotes viscous fingering phenomenon.Connate water makes viscous fingers longer and more irregular consisting of large number of tributaries leading to the ultimate oil recovery reduction.Therefore,higher in-situ water content can worsen this condition.Besides,this water can play as a barrier between oil and gas phases and adversely affect the gas diffusion,which results in EOR reduction.On the other hand,from gas storage point of view,it should be noted that CO2 solubility is not the same in the water and oil phases.In this study for a specified water salinity,the effects of different connate water saturations(Swc)on the ultimate oil recovery and CO2 storage capacity during secondary CWI are being presented using carbonate rock samples from one of Iranian carbonate oil reservoir.The results showed higher oil recovery and CO2 storage in the case of lower connate water saturation,as 14%reduction of Swc resulted in 20%and 16%higher oil recovery and CO2 storage capacity,respectively.展开更多
The syntheses of nanosized carbonated hydroxyapatite （CHA） were performed by comparing dropwise and direct pouring of acetone solution of Ca（NO3）2·4H2O into mixture of （NH4）2HPO4 and NH4HCO3 at room tempera...The syntheses of nanosized carbonated hydroxyapatite （CHA） were performed by comparing dropwise and direct pouring of acetone solution of Ca（NO3）2·4H2O into mixture of （NH4）2HPO4 and NH4HCO3 at room temperature controlled at pH 11. Direct pouring method was later applied to study the increment of carbonate content in syntheses. The as-synthesized powders were characterized by various characterization techniques. The crystallographic results of the produced powders were obtained from X-ray diffraction analysis, whilst the carbonate content in the produced powders was determined by the CHNS/O elemental analyzer. Fourier transform infrared analysis confirmed that the CHA powders formed were B-type. Field emission scanning electron microscopy revealed that the powders were highly agglomerated in nanosized range and hence energy filtered transmission electron microscopy was employed to show elongated particles which decreased with increasing carbonate content.展开更多
The characteristics of reactive magnesia(MgO)-carbonated silt in respect to long-term stability have not been well understood in severely cold climate despite the usage of reactive MgO in enhancing the engineering per...The characteristics of reactive magnesia(MgO)-carbonated silt in respect to long-term stability have not been well understood in severely cold climate despite the usage of reactive MgO in enhancing the engineering performances.Under the binder content of 15%and initial water content of 25%,MgO-admixed silt specimens were carbonized for 3 h and 6 h and then subjected to different numbers of freezingthawing(F-T)cycles.After different F-T cycles,the physico-mechanical properties of MgO-carbonated silt were analyzed in comparison with Portland cement(PC)-stabilized silt through physical and unconfined compression tests.Besides,a series of micro tests on MgO-carbonated specimens was performed including X-ray diffraction(XRD),scanning electron microscopy(SEM)and mercury intrusion porosimetry(MIP)tests.The results demonstrate that both mass change ratio and moisture content of carbonated/stabilized silt decrease,and these values of MgO-carbonated silt are significantly lower while the density is higher compared to PC-stabilized silt.The strengths and moduli of MgO-carbonated silt are still two times higher than those of PC-stabilized specimens and the strength change ratio of keeps above0.8 after F-T cycles.There is no visible transformation between nesquehonite and dypingite/hydromagnesite,although the XRD peaks of nesquehonite decrease and the bonding and filling effects weaken slightly.After 6 and 10 F-T cycles,the pore-size characteristics changed from a unimodal distribution to a three-peak and bimodal distribution,respectively.The total,macro and large pore volumes increase obviously while the medium and small pore volumes decrease except for intra-aggregate pore.The findings show better F-T durability of MgO-carbonated silt,which would be helpful for facilitating the application of MgO carbonation in the soil treatment.展开更多
Most fractured carbonate oil reservoirs have oil-wet rocks.Therefore,the process of imbibing water from the fractures into the matrix is usually poor or basically does not exist due to negative capillary pressure.To a...Most fractured carbonate oil reservoirs have oil-wet rocks.Therefore,the process of imbibing water from the fractures into the matrix is usually poor or basically does not exist due to negative capillary pressure.To achieve appropriate ultimate oil recovery in these reservoirs,a water-based enhanced oil recovery method must be capable of altering the wettability of matrix blocks.Previous studies showed that carbonated water can alter wettability of carbonate oil-wet rocks toward less oil-wet or neutral wettability conditions,but the degree of modification is not high enough to allow water to imbibe spontaneously into the matrix blocks at an effective rate.In this study,we manipulated carbonated brine chemistry to enhance its wettability alteration features and hence to improve water imbibition rate and ultimate oil recovery upon spontaneous imbibition in dolomite rocks.First,the contact angle and interfacial tension(IFT)of brine/crude oil systems were measured for several synthetic brine samples with different compositions.Thereafter,two solutions with a significant difference in WAI(wettability alteration index)but approximately equal brine/oil IFT were chosen for spontaneous imbibition experiments.In the next step,spontaneous imbibition experiments at ambient and high pressures were conducted to evaluate the ability of carbonated smart water in enhancing the spontaneous imbibition rate and ultimate oil recovery in dolomite rocks.Experimental results showed that an appropriate adjustment of the imbibition brine(i.e.,carbonated smart water)chemistry improves imbibition rate of carbonated water in oil-wet dolomite rocks as well as the ultimate oil recovery.展开更多
Enhanced oil recovery(EOR)methods are mostly based on different phenomena taking place at the interfaces between fluid–fluid and rock–fluid phases.Over the last decade,carbonated water injection(CWI)has been conside...Enhanced oil recovery(EOR)methods are mostly based on different phenomena taking place at the interfaces between fluid–fluid and rock–fluid phases.Over the last decade,carbonated water injection(CWI)has been considered as one of the multi-objective EOR techniques to store CO2 in the hydrocarbon bearing formations as well as improving oil recovery efficiency.During CWI process,as the reservoir pressure declines,the dissolved CO2 in the oil phase evolves and gas nucleation phenomenon would occur.As a result,it can lead to oil saturation restoration and subsequently,oil displacement due to the hysteresis effect.At this condition,CO2 would act as insitu dissolved gas into the oil phase,and play the role of an artificial solution gas drive(SGD).In this study,the effect of SGD as an extra oil recovery mechanism after secondary and tertiary CWI(SCWI-TCWI)modes has been experimentally investigated in carbonate rocks using coreflood tests.The depressurization tests resulted in more than 25%and 18%of original oil in place(OOIP)because of the SGD after SCWI and TCWI tests,respectively.From the ultimate enhanced oil recovery point of view,the efficiency of SGD was observed to be more than one-third of that of CWI itself.Furthermore,the pressure drop data revealed that the system pressure depends more on the oil production pattern than water production.展开更多
The e ects of CO2 and salt type on the interfacial tension(IFT) between crude oil and carbonated brine(CB) have not been fully understood. This study focuses on measuring the dynamic IFT between acidic crude oil with ...The e ects of CO2 and salt type on the interfacial tension(IFT) between crude oil and carbonated brine(CB) have not been fully understood. This study focuses on measuring the dynamic IFT between acidic crude oil with a total acid number of 1.5 mg KOH/g and fully CO2-saturated aqueous solutions consisting of 15,000 ppm of KCl, NaCl, CaCl2 and MgCl2 at 30 °C and a wide range of pressures(500–4000 psi). The results of IFT measurements showed that solvation of CO2 into all the studied aqueous solutions led to an increase in IFT of acidic crude oil(i.e., comparison of IFT of crude oil/CB and crude oil/brine), while no significant e ect was observed for pressure. In contrast, the obtained results of studied salts indicated a positive e ect on the IFT reduction of acidic crude oil/carbonated water(CW)(i.e., comparison of IFT of crude oil/CB and crude oil/CW).展开更多
Hierarchically nanostructured porous carbonated hydroxyapatite coatings (HNPCs) on Ti6Al4V substrate were fabricated by a two-stage application route: fabrication of nacre coatings (NCs) on Ti6Al4V substrate by electr...Hierarchically nanostructured porous carbonated hydroxyapatite coatings (HNPCs) on Ti6Al4V substrate were fabricated by a two-stage application route: fabrication of nacre coatings (NCs) on Ti6Al4V substrate by electrophoretic technique, and conversion of NCs to HNPCs in a phosphate buffer solution (PBS) by microwave irradiation method. Their samples were characterized by using XRD, FT-IR, SEM, TEM, and N2 adsorption-desorption isotherms. The results show that the microwave irradiation technique improves obviously the conversion rate of NCs to HNPCs as compared with conventional method. After soaking the NCs in the PBS, calcium ions are released from the nacre particles and react with phosphate ions to form carbonated hydroxyapatite nanoparticles. These nanoparticles aggregate to form the plate-like carbonated apatite. The mesopores with a size of about 3.9 nm and macropores with the diameters of 1~4μm exist within and among the carbonated apatite plates, respectively. Simulated body fluid immersion tests reveal that the HNPCs have a good in vitro bioactivity.展开更多
Nanocrystal carbonated hydroxyapatite was prepared by lecithin-controlled chemical precipitation in synthetic body fluid （SBF）. The reactant was aged and heated at 850℃ for crystallization. The morphology and mic...Nanocrystal carbonated hydroxyapatite was prepared by lecithin-controlled chemical precipitation in synthetic body fluid （SBF）. The reactant was aged and heated at 850℃ for crystallization. The morphology and microstructure of the carbonated hydroxyapatite were investigated using transmission electron microscope （TEM）, X-ray diffraction （ XRD ） and FTIR. The experimental results demonstrate that the shapes of carbonated hydroxyapdtite particles display spheres with the average size of 20- 28 nm, and carbonated hydroxyapatite contained carbonate ions, similar to mineral of bone tissues.展开更多
Background: The consumption of carbonated beverages has been shown to increase the risk of developing metabolic syndrome. The associations between the consumption of carbonated beverages and left arterial dimension or...Background: The consumption of carbonated beverages has been shown to increase the risk of developing metabolic syndrome. The associations between the consumption of carbonated beverages and left arterial dimension or left ventricular mass are believed to be likely related to the greater body weight of carbonated beverage drinkers relative to non-drinkers. Nonetheless, little is known about the association between the consumption of carbonated beverages and out-of-hospital cardiac arrests (OHCAs) in Japan. Methods: We compared the age-adjusted incidence of OHCAs to the expenditures on various beverages per person between 2005 and 2011 in the 47 prefectures of Japan. Patients who suffered from OHCAs of cardiac and non-cardiac origin were enrolled in All-Japan Utstein Registry of the Fire and Disaster Management Agency. The expenditures on various beverages per person in the 47 prefectures in Japan were obtained from data published by the Ministry of Health, Labour and Welfare of Japan. Results: There were 797,422 cases of OHCA in the All-Japan Utstein registry between 2005 and 2011, including 11,831 cases who did not receive resuscitation. Among these 785,591 cases of OHCA, 435,064 (55.4%) were classified as cardiac origin and 350,527 (44.6%) were non-cardiac origin. Non-cardiac origin included cerebrovascular disease, respiratory disease, malignant tumor, and exogenous disease (4.8%, 6.1%, 3.5%, and 18.9%, respectively). The expenditures on carbonated beverages were significantly associated with OHCAs of cardiac origin (r = 0.30, p = 0.04), but not non-cardiac origin (r = -0.03, p = 0.8). Expenditures on other beverages, including green tea, tea, coffee, cocoa, fruit or vegetable juice, fermented milk beverage, milk beverage, and mineral water, were not significantly associated with OHCAs of cardiac origin. Conclusion: Carbonated beverage consumption was significantly and positively associated with OHCAs of cardiac origin in Japan, indicating that beverage habits might play a role in OHCAs of cardiac origin.展开更多
Erosion is one of serious oral health problems among Japanese children. Some dentists argue that brushing just after food/drink intake induces enamel abrasion. Objectives of this study were to evaluate amount of calci...Erosion is one of serious oral health problems among Japanese children. Some dentists argue that brushing just after food/drink intake induces enamel abrasion. Objectives of this study were to evaluate amount of calcium elution from bovine enamel due to single and short immersion into carbonated soft drink, to calculate depth of the eroded lesion, and to determine when to brush teeth after carbonated soft drink intake from the view point of preventing enamel abrasion. Four enamel specimens were made from each of eight bovine teeth. The specimens were covered by quick-cure resin except for enamel surfaces. The four specimens from each bovine tooth were classified into three, six, nine, and 12 minutes immersion (IM3, IM6, IM9, and IM12) groups and immersed separately in five mL of carbonated soft drink. After the immersion, the calcium concentration of the original drink and the drink samples were evaluated using atomic absorption spectrophotometry. The dimension of each enamel specimen was calculated using a planimeter. The amount of eluted calcium per unit area of the enamel specimen into each drink sample was obtained. The depth of the demineralized lesion was obtained by dividing the amount of calcium elution per unit area by the concentration of calcium in enamel and the specific gravity of enamel. The lesion depth of the IM3 group was significantly lower than those in the IM6, IM9, and IM12 groups. The mean lesion depth in the IM12 group which showed the deepest lesion depth was 0.21 μm. As conclusions, the erosive lesion depth due to intake of carbonated soft drink was much shallower than remineralized enamel surface of a white spot lesion which can be repaired in plaque fluid in a short time, suggesting such erosion hardly causes tooth wear, hence it was suggested that brushing teeth just after the intake was recommended.展开更多
An attempt was made to improve the adsorption capability of the normal sand to be used as adsorbent for phenol and cadmium This has been done by producing a coated sand media. The coating process was done using emulsi...An attempt was made to improve the adsorption capability of the normal sand to be used as adsorbent for phenol and cadmium This has been done by producing a coated sand media. The coating process was done using emulsion asphalt to convert the normal sand to carbonated sand by using chemical treatment with sulfuric acid. The production process involves mixing of the sand with asphalt and an acid, then subjecting the mix to a heating process. Different mixing ratios, heating temperatures and times （activation times） were tried to obtain the optimum conditions at which the highest removal efficiency is obtained. Three types of acids were tried acetic acid, phosphoric acid and sulfuric acid. It was found that the sulfuric acid requires the lowest activation time, hence selected for the production. The removal efficiency of the produced media was significantly affected by the temperature, mixing ratio and activation heating time. The results show that, the optimum conditions for the production process are 350 , （1：2：3） （Asphalt/acid/sand） and 52 min for temperature, mixing ratio and activation heating time respectively. The final product was tested and found effective as an adsorbent media for phenol and cadmium. The removal efficiencies of these two pollutants in a batch adsorber were found 82.42% and 86.67%, respectively. The X-R diffraction and FTIR spectra tests had proved this media as an adsorbent.展开更多
A set of measurements have been conducted, using gamma spectrometry technique, in order to determine the activity-level in some carbonated soft drinks. The obtained activity is about 0.18 ± 0.07 Bq/l for <sup&...A set of measurements have been conducted, using gamma spectrometry technique, in order to determine the activity-level in some carbonated soft drinks. The obtained activity is about 0.18 ± 0.07 Bq/l for <sup>137</sup>Cs, whereas it is less than 0.13, 0.18 and 4.51 Bq/l respectively for <sup>212</sup>Pb, <sup>214</sup>Pb and <sup>40</sup>K. The total average annual dose is about 3.49, 1.69 and 1.68 μSv/y respectively for 7 - 12, 12 - 17 and >17 years old person leading to a radiological risk about 0.142 for adolescent and adults. The obtained results show no significant radiation dose and radiation hazard on human health due to the consumption of these carbonated soft drinks.展开更多
基金Project(2021YJ059)supported by the Research Project of China Academy of Railway Sciences。
文摘The study aims to investigate the carbonated water erosion mechanism of lining concrete in tunnels traversing karst environment and enhance its resistance.In this study,dynamic carbonated water erosion was simulated to assess erosion depth,microstructure,phase migrations,and pore structure in various tunnel lining cement-based materials.Additionally,Ca^(2+)leaching was analyzed,and impact of Ca/Si molar ratio in hydration products on erosion resistance was discussed by thermodynamic calculations.The results indicate that carbonated water erosion caused rough and porous surface on specimens,with reduced portlandite and CaCO_(3) content,increased porosity,and an enlargement of pore size.The thermodynamic calculations indicate that the erosion is spontaneous,driven by physical dissolution and chemical reactions dominated by Gibbs free energy.And the erosion reactions proceed more spontaneously and extensively when Ca/Si molar ratio in hydration products was higher.Therefore,cement-based materials with higher portlandite content exhibit weaker erosion resistance.Model-building concrete,with C-S-H gel and portlandite as primary hydration products,has greater erosion susceptibility than shotcrete with ettringite as main hydration product.Moreover,adding silicon-rich mineral admixtures can enhance the erosion resistance.This research offers theory and tech insights to boost cement-based material resistance against carbonated water erosion in karst tunnel engineering.
基金the financial support from Innovative Research Group Project of Natural Science Foundation of Hebei Province(No.E2022209093)Central Guidance Local Science and Technology Development Fund Project of Hebei Province(No.236Z3803G)+1 种基金Scientific and Technological Project of Tangshan(No.23130205E)Youth Teacher Pre Research Fund Project of the School of Metallurgy and Energy(No.YJY20244373).
文摘A slurry-phase carbonation technique was utilized,employing argon oxygen decarburization slag(AOD slag)as a source of calcium and MgCl_(2) as a regulator for the crystal morphology of acicular aragonite.Subsequently,the carbonated AOD slag,enriched with acicular aragonite,was employed in fabricating composite cementitious materials,followed by an analysis of their evolution in hydration heat,hydration products,and microscopic morphology.Additionally,it delved into the mechanism through which acicular aragonite enhances the stength of composite cementitious materials.Moreover,advanced simulation software for engineering and sciences(ABAQUS)was utilized to simulate the compressive performance of composite mortar with varying dosages of acicular aragonite.The findings demonstrate that the carbonated AOD slag,containing 83.4%acicular aragonite(with an average aspect ratio of 21.31),exhibited commendable compatibility with cement.Moderate integration of carbonated AOD slag facilitated the formation of calcium sulfoaluminate hydrate(AFt)phases.The acicular aragonite within the cementitious matrix showcased remarkable filling effects.As the dosage of carbonated AOD slag increased,flexural and compressive strengths of cement mortar initially rose before declining.Upon reaching a 6%cement inclusion of carbonated AOD slag,the various constituents of the cementitious material displayed optimal synergy.The numerical simulation results confirmed the experimental findings,demonstrating a favorable increase in compressive strength and flexural strength with the addition of acicular aragonite.The acicular aragonite strengthened the matrix by serving bridging and pull-out functions.
基金supported by the Fundamental Research Program of Shanxi Province(Grant Nos.202203021222188 and 202303021211166)Scientific Research Fund of Taiyuan University of Science and Technology(Grant No.20222073)+1 种基金Award Fund for Outstanding Doctors in Shanxi Province(Grant No.20232047)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(Grant No.2022L280).
文摘The crevice corrosion of the reinforcing steel in the carbonated simulated concrete pore solutions(SCPSs)containing 0.04 mol/L chloride was investigated.In comparison,the steel without crevice covered on its surface was also studied.Results showed that the crevice corrosion in the uncarbonated SCPS was not triggered and the steel remained passivity by suppressing the anodic dissolution in the crevice interior.As SCPS was carbonated to have pH values of 10.5 and 11.5,the crevice corrosion was easier to be activated than the widely reported pitting corrosion owing to the rapid oxygen depletion within the crevice,but the crevice corrosion damage might be alleviated to a certain extent due to the relative compact surface film formed inside the crevice.The further carbonation led to the activation dissolution of both the crevice interior and exterior,causing the more serious corrosion damage.Corrosion process of the crevice corrosion was systematically analyzed by combining the electrochemical measurement results and Evens polarization diagram.
基金the National Natural Science Foundation of China(Grant Nos.42177163 and 42071080)the China Postdoctoral Science Foundation(Grant No.2022M723347).
文摘Due to the limited hydration capacity,solidification/stabilization(S/S)with waste concrete powder(WCP)has a low strength.Carbonation can reduce carbon dioxide(CO_(2))emissions and improve strength of lead-contaminated soil,but its mechanism and environmental behaviors are unclear.In light of this,a comprehensive study was conducted on the compressive strength,lead immobilization,conductivity characteristics,and carbonation mechanism of carbonated Pb-contaminated soils stabilized with WCP compared to calcining 600℃WCP.Results indicated that with carbonation,the compressive strength of the samples was significantly improved at the early stage(1 d),resulting in increased unconfined compressive strength(UCS)by 2.5-5.2 times due to the filling of pores by calcite.It negatively affected the lead immobilization capacity of highly doped(30%)samples,while this effect reversed after 3 d of carbonating due to the reduced alkaline environment.The lead immobilization capacity decreased after 28 d of carbonating due to the cracking of samples and the influence of a lower pH on the solubility of lead-carbonated hydroxide((PbCO_(3))_(2)Pb(OH)_(2)).The water evaporation(saturation<16.8%)led to dry shrinkage cracking and decreased UCS of the samples.Based on this finding,a conductivity model was developed for carbonated and cured samples,accurately predicting changes in saturation levels(R^(2)=0.98).A relationship between conductivity and UCS or lead immobilization capacity was proposed.This research proposed an innovative method for the reduction of CO_(2)emission as well as laid down a theoretical basis for the recovery of WCP and lead-contaminated soils through carbonation.
基金Supported by Shanghai Municipal Hospital Emerging Frontier Technology Joint Project,No.SHDC12019105Shanghai Science and Technology Development Funds,No.24YF2758200National Natural Science Foundation of China,No.82100699.
文摘BACKGROUND The clinical effectiveness of magnetically controlled capsule endoscopy(MCE)is well established.However,problems,such as abdominal distension,insufficient gastric filling,and prolonged gastric retention time,persist with MCE gastric preparations.AIM To compare gastric filling using a carbonated soft drink with that using pure water during MCE.METHODS We performed an open-label randomised controlled trial at the Endoscopy Centre of Changhai Hospital in Shanghai.Patients aged 18-80 years,with or without gastrointestinal symptoms,scheduled for MCE were consecutively recruited.Those who provided informed consent were randomly assigned to the carbonated soft drink group(C group)or water group(W group)in a 1:1 ratio.For patients in the W group,1000 mL of water was ingested to distend the stomach,whereas for patients in the C group,550 mL of carbonated soft drink was provided,and patients were required to drink quickly while minimising burping.The primary endpoint was the number of patients with a gastric filling score of≥4 within 5 minutes after the capsule entered the stomach.RESULTS From December 3,2020 to May 17,2021,252 patients(141 men),aged 18-77 years,were assigned to the C(n=126)and W(n=126)groups.For the primary outcome,123 patients in the C group achieved a gastric filling score of≥4(97.62%vs 80.16%,P<0.0001).More patients in the C group had the highest gastric filling scores within the first 5 min(78.57%vs 29.37%,P<0.0001)and 10 minutes(54.76%vs 13.49%,P<0.0001)after the capsule entered the stomach.More patients in the W group required extra liquid for gastric refilling(1.59%vs 16.67%,P<0.0001).Transpyloric passage of the capsule under magnetic control was successfully performed in 43 patients in the C group(P<0.0001),accompanied by a shorter gastric transit time(53.27±53.83 minutes vs 71.12±52.19 minutes,P=0.001).CONCLUSION Carbonated soft drinks demonstrated superior and more sustained gastric filling compared with those of water alone,with the potential to promote gastric emptying.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFC3707900)the National Natural Science Foundation of China(Grant Nos.42030710 and 42472337).
文摘The presence of heavy metals in soil negatively impacts its mechanical properties.Reactive MgO carbonation presents a promising approach to enhance the solidification of Pb-contaminated sandy soils.However,the mechanical properties and structural behavior of contaminated soils during carbonation can vary significantly due to differences in soil composition.This study examines the potential application and underlying mechanisms of reactive MgO carbonation in improving the mechanical properties of Pb-contaminated red clay.The findings demonstrate that Pb-contaminated red clay transitions from a plastic to a brittle state following reactive MgO carbonation.After 1 h of treatment,the strength of the red clay exceeded 3 MPa,even at high Pb^(2+)concentrations.The deformation modulus to unconfined compressive strength(UCS)ratio was calculated to be 37.761,with the failure strain primarily ranging from 1.5%to 4.0%.A strength prediction model for the reactive MgO-stabilized Pb-contaminated red clay was proposed,which showed good predictive accuracy.Furthermore,reactive MgO carbonation significantly reduced the Pb leaching concentration in the high-level Pb-contaminated soil to below 0.1 mg/L.Microscopic analysis revealed that an optimal amount of hydrated magnesium carbonates(HMCs)formed a stable and compact structure with the soil particles.However,long-term carbonation causes red clay particles to become sandy,and excessive HMCs can harm the soil structure.Therefore,to maximize the strength improvement while avoiding structural damage,the carbonation time should be controlled to 1 h.
基金supported by National Key Research and Development Program of China(Grant No.2023YFB4104200)Liaoning Foundation Research Projects for Application(Grant No.2023JH2/101300005)National Natural Science Foundation of China(Grant No.51976024,52076030)。
文摘Carbonated water injection(CWI)is a promising enhanced oil recovery(EOR)technology that has received much attention in co-optimizing CO_(2) storage and oil recovery.This study provides a comprehensive review of the fluid system properties and the underlying changes in rock-fluid interactions that drive the CWI-EOR mechanisms.Previous research has indicated that CWI can enhance oil recovery by shifting reservoir wettability towards a more water-wet state and reducing interfacial tension(IFT).However,this study reveals that there is still room for discussion in this area.Notably,the potential of CWI to alter reservoir permeability has not yet been explored.The varying operational conditions of the CWI process,namely temperature,pressure,injection rate,salinity,and ionic composition,lead to different levels of oil recovery factors.Herein,we aim to meticulously analyze their impact on oil recovery performance and outline the optimal operational conditions.Pressure,for instance,positively influences oil recovery rate and CWI efficiency.On one hand,higher operating pressures enhance the effectiveness of CW due to increased CO_(2)solubility.On the other hand,gas exsolution events in depleted reservoirs provide additional energy for oil movement along gas growth pathways.However,CWI at high carbonation levels does not offer significant benefits over lower carbonation levels.Additionally,lower temperatures and injection rates correlate with higher recovery rates.Further optimization of solution chemistry is necessary to determine the maximum recovery rates under optimal conditions.Moreover,this review comprehensively covers laboratory experiments,numerical simulations,and field applications involving the CWI process.However,challenges such as pipeline corrosion,potential reservoir damage,and produced water treatment impact the further application of CWI in EOR technologies.These issues can affect the expected oil recovery rates,thereby reducing the economic returns of EOR projects.Finally,this review introduces current research trends and future development prospects based on recently published studies in the field of CWI.The conclusions of this study aid readers in better understanding the latest advancements in CWI technology and the strengths and limitations of the techniques used,providing directions for further development and application of CWI.
基金Funded by Joint Funds of the National Natural Science Foundation of China(No.U1904188)Jiangxi Provincial Department of Education Science and Technology Project(Nos.GJJ171079,GJJ181023 and GJJ181022)。
文摘Carbonated recycled powder as cementitious auxiliary material can reduce carbon emissions and realize high-quality recycling of recycled concrete.In this paper,microscopic property of recycled powder with three carbonation methods was tested through XRD and SEM,the mechanical property and microstructure of recycled powder mortar with three replacement rates were studied by ISO method and SEM,and the strengthening mechanism was analyzed.The results showed that the mechanical property of recycled powder mortar decreased with the increasing of replacement rate.It is suggested that the replacement rate of recycled powder should not exceed 20%.The strength index and activity index of carbonated recycled powder mortar were improved,in which the flexural strength was increased by 27.85%and compressive strength was increased by 20%at the maximum.Recycled powder can be quickly and completely carbonated,and the improvement effect of CH pre-soaking carbonation was the best.The activity index of carbonated recycled powder can meet the requirements of Grade II technical standard for recycled powder.Microscopic results revealed the activation mechanism of carbonated recycled powder such as surplus calcium source effect,alkaline polycondensation effect and carbonation enhancement effect.
文摘Carbonated water injection(CWI)is known as an efficient technique for both CO2 storage and enhanced oil recovery(EOR).During CWI process,CO2 moves from the water phase into the oil phase and results in oil swelling.This mechanism is considered as a reason for EOR.Viscous fingering leading to early breakthrough and leaving a large proportion of reservoir un-swept is known as an unfavorable phenomenon during flooding trials.Generally,instability at the interface due to disturbances in porous medium promotes viscous fingering phenomenon.Connate water makes viscous fingers longer and more irregular consisting of large number of tributaries leading to the ultimate oil recovery reduction.Therefore,higher in-situ water content can worsen this condition.Besides,this water can play as a barrier between oil and gas phases and adversely affect the gas diffusion,which results in EOR reduction.On the other hand,from gas storage point of view,it should be noted that CO2 solubility is not the same in the water and oil phases.In this study for a specified water salinity,the effects of different connate water saturations(Swc)on the ultimate oil recovery and CO2 storage capacity during secondary CWI are being presented using carbonate rock samples from one of Iranian carbonate oil reservoir.The results showed higher oil recovery and CO2 storage in the case of lower connate water saturation,as 14%reduction of Swc resulted in 20%and 16%higher oil recovery and CO2 storage capacity,respectively.
基金Universiti Sains Malaysia for the USM FellowshipUSM-RU-PGRS(8033006)for the financial support
文摘The syntheses of nanosized carbonated hydroxyapatite （CHA） were performed by comparing dropwise and direct pouring of acetone solution of Ca（NO3）2·4H2O into mixture of （NH4）2HPO4 and NH4HCO3 at room temperature controlled at pH 11. Direct pouring method was later applied to study the increment of carbonate content in syntheses. The as-synthesized powders were characterized by various characterization techniques. The crystallographic results of the produced powders were obtained from X-ray diffraction analysis, whilst the carbonate content in the produced powders was determined by the CHNS/O elemental analyzer. Fourier transform infrared analysis confirmed that the CHA powders formed were B-type. Field emission scanning electron microscopy revealed that the powders were highly agglomerated in nanosized range and hence energy filtered transmission electron microscopy was employed to show elongated particles which decreased with increasing carbonate content.
基金the support of the National Natural Science Foundation of China(Grant Nos.41902286 and 41972269)Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences(Grant No.Z019026)。
文摘The characteristics of reactive magnesia(MgO)-carbonated silt in respect to long-term stability have not been well understood in severely cold climate despite the usage of reactive MgO in enhancing the engineering performances.Under the binder content of 15%and initial water content of 25%,MgO-admixed silt specimens were carbonized for 3 h and 6 h and then subjected to different numbers of freezingthawing(F-T)cycles.After different F-T cycles,the physico-mechanical properties of MgO-carbonated silt were analyzed in comparison with Portland cement(PC)-stabilized silt through physical and unconfined compression tests.Besides,a series of micro tests on MgO-carbonated specimens was performed including X-ray diffraction(XRD),scanning electron microscopy(SEM)and mercury intrusion porosimetry(MIP)tests.The results demonstrate that both mass change ratio and moisture content of carbonated/stabilized silt decrease,and these values of MgO-carbonated silt are significantly lower while the density is higher compared to PC-stabilized silt.The strengths and moduli of MgO-carbonated silt are still two times higher than those of PC-stabilized specimens and the strength change ratio of keeps above0.8 after F-T cycles.There is no visible transformation between nesquehonite and dypingite/hydromagnesite,although the XRD peaks of nesquehonite decrease and the bonding and filling effects weaken slightly.After 6 and 10 F-T cycles,the pore-size characteristics changed from a unimodal distribution to a three-peak and bimodal distribution,respectively.The total,macro and large pore volumes increase obviously while the medium and small pore volumes decrease except for intra-aggregate pore.The findings show better F-T durability of MgO-carbonated silt,which would be helpful for facilitating the application of MgO carbonation in the soil treatment.
基金financial support from National Iranian South Oil Company(NISOC)
文摘Most fractured carbonate oil reservoirs have oil-wet rocks.Therefore,the process of imbibing water from the fractures into the matrix is usually poor or basically does not exist due to negative capillary pressure.To achieve appropriate ultimate oil recovery in these reservoirs,a water-based enhanced oil recovery method must be capable of altering the wettability of matrix blocks.Previous studies showed that carbonated water can alter wettability of carbonate oil-wet rocks toward less oil-wet or neutral wettability conditions,but the degree of modification is not high enough to allow water to imbibe spontaneously into the matrix blocks at an effective rate.In this study,we manipulated carbonated brine chemistry to enhance its wettability alteration features and hence to improve water imbibition rate and ultimate oil recovery upon spontaneous imbibition in dolomite rocks.First,the contact angle and interfacial tension(IFT)of brine/crude oil systems were measured for several synthetic brine samples with different compositions.Thereafter,two solutions with a significant difference in WAI(wettability alteration index)but approximately equal brine/oil IFT were chosen for spontaneous imbibition experiments.In the next step,spontaneous imbibition experiments at ambient and high pressures were conducted to evaluate the ability of carbonated smart water in enhancing the spontaneous imbibition rate and ultimate oil recovery in dolomite rocks.Experimental results showed that an appropriate adjustment of the imbibition brine(i.e.,carbonated smart water)chemistry improves imbibition rate of carbonated water in oil-wet dolomite rocks as well as the ultimate oil recovery.
文摘Enhanced oil recovery(EOR)methods are mostly based on different phenomena taking place at the interfaces between fluid–fluid and rock–fluid phases.Over the last decade,carbonated water injection(CWI)has been considered as one of the multi-objective EOR techniques to store CO2 in the hydrocarbon bearing formations as well as improving oil recovery efficiency.During CWI process,as the reservoir pressure declines,the dissolved CO2 in the oil phase evolves and gas nucleation phenomenon would occur.As a result,it can lead to oil saturation restoration and subsequently,oil displacement due to the hysteresis effect.At this condition,CO2 would act as insitu dissolved gas into the oil phase,and play the role of an artificial solution gas drive(SGD).In this study,the effect of SGD as an extra oil recovery mechanism after secondary and tertiary CWI(SCWI-TCWI)modes has been experimentally investigated in carbonate rocks using coreflood tests.The depressurization tests resulted in more than 25%and 18%of original oil in place(OOIP)because of the SGD after SCWI and TCWI tests,respectively.From the ultimate enhanced oil recovery point of view,the efficiency of SGD was observed to be more than one-third of that of CWI itself.Furthermore,the pressure drop data revealed that the system pressure depends more on the oil production pattern than water production.
文摘The e ects of CO2 and salt type on the interfacial tension(IFT) between crude oil and carbonated brine(CB) have not been fully understood. This study focuses on measuring the dynamic IFT between acidic crude oil with a total acid number of 1.5 mg KOH/g and fully CO2-saturated aqueous solutions consisting of 15,000 ppm of KCl, NaCl, CaCl2 and MgCl2 at 30 °C and a wide range of pressures(500–4000 psi). The results of IFT measurements showed that solvation of CO2 into all the studied aqueous solutions led to an increase in IFT of acidic crude oil(i.e., comparison of IFT of crude oil/CB and crude oil/brine), while no significant e ect was observed for pressure. In contrast, the obtained results of studied salts indicated a positive e ect on the IFT reduction of acidic crude oil/carbonated water(CW)(i.e., comparison of IFT of crude oil/CB and crude oil/CW).
基金Supported by National Natural Science Foundation of China (No.51002095)Innovation Foundation of Shanghai Education Committee (No.11YZ86)
文摘Hierarchically nanostructured porous carbonated hydroxyapatite coatings (HNPCs) on Ti6Al4V substrate were fabricated by a two-stage application route: fabrication of nacre coatings (NCs) on Ti6Al4V substrate by electrophoretic technique, and conversion of NCs to HNPCs in a phosphate buffer solution (PBS) by microwave irradiation method. Their samples were characterized by using XRD, FT-IR, SEM, TEM, and N2 adsorption-desorption isotherms. The results show that the microwave irradiation technique improves obviously the conversion rate of NCs to HNPCs as compared with conventional method. After soaking the NCs in the PBS, calcium ions are released from the nacre particles and react with phosphate ions to form carbonated hydroxyapatite nanoparticles. These nanoparticles aggregate to form the plate-like carbonated apatite. The mesopores with a size of about 3.9 nm and macropores with the diameters of 1~4μm exist within and among the carbonated apatite plates, respectively. Simulated body fluid immersion tests reveal that the HNPCs have a good in vitro bioactivity.
文摘Nanocrystal carbonated hydroxyapatite was prepared by lecithin-controlled chemical precipitation in synthetic body fluid （SBF）. The reactant was aged and heated at 850℃ for crystallization. The morphology and microstructure of the carbonated hydroxyapatite were investigated using transmission electron microscope （TEM）, X-ray diffraction （ XRD ） and FTIR. The experimental results demonstrate that the shapes of carbonated hydroxyapdtite particles display spheres with the average size of 20- 28 nm, and carbonated hydroxyapatite contained carbonate ions, similar to mineral of bone tissues.
文摘Background: The consumption of carbonated beverages has been shown to increase the risk of developing metabolic syndrome. The associations between the consumption of carbonated beverages and left arterial dimension or left ventricular mass are believed to be likely related to the greater body weight of carbonated beverage drinkers relative to non-drinkers. Nonetheless, little is known about the association between the consumption of carbonated beverages and out-of-hospital cardiac arrests (OHCAs) in Japan. Methods: We compared the age-adjusted incidence of OHCAs to the expenditures on various beverages per person between 2005 and 2011 in the 47 prefectures of Japan. Patients who suffered from OHCAs of cardiac and non-cardiac origin were enrolled in All-Japan Utstein Registry of the Fire and Disaster Management Agency. The expenditures on various beverages per person in the 47 prefectures in Japan were obtained from data published by the Ministry of Health, Labour and Welfare of Japan. Results: There were 797,422 cases of OHCA in the All-Japan Utstein registry between 2005 and 2011, including 11,831 cases who did not receive resuscitation. Among these 785,591 cases of OHCA, 435,064 (55.4%) were classified as cardiac origin and 350,527 (44.6%) were non-cardiac origin. Non-cardiac origin included cerebrovascular disease, respiratory disease, malignant tumor, and exogenous disease (4.8%, 6.1%, 3.5%, and 18.9%, respectively). The expenditures on carbonated beverages were significantly associated with OHCAs of cardiac origin (r = 0.30, p = 0.04), but not non-cardiac origin (r = -0.03, p = 0.8). Expenditures on other beverages, including green tea, tea, coffee, cocoa, fruit or vegetable juice, fermented milk beverage, milk beverage, and mineral water, were not significantly associated with OHCAs of cardiac origin. Conclusion: Carbonated beverage consumption was significantly and positively associated with OHCAs of cardiac origin in Japan, indicating that beverage habits might play a role in OHCAs of cardiac origin.
文摘Erosion is one of serious oral health problems among Japanese children. Some dentists argue that brushing just after food/drink intake induces enamel abrasion. Objectives of this study were to evaluate amount of calcium elution from bovine enamel due to single and short immersion into carbonated soft drink, to calculate depth of the eroded lesion, and to determine when to brush teeth after carbonated soft drink intake from the view point of preventing enamel abrasion. Four enamel specimens were made from each of eight bovine teeth. The specimens were covered by quick-cure resin except for enamel surfaces. The four specimens from each bovine tooth were classified into three, six, nine, and 12 minutes immersion (IM3, IM6, IM9, and IM12) groups and immersed separately in five mL of carbonated soft drink. After the immersion, the calcium concentration of the original drink and the drink samples were evaluated using atomic absorption spectrophotometry. The dimension of each enamel specimen was calculated using a planimeter. The amount of eluted calcium per unit area of the enamel specimen into each drink sample was obtained. The depth of the demineralized lesion was obtained by dividing the amount of calcium elution per unit area by the concentration of calcium in enamel and the specific gravity of enamel. The lesion depth of the IM3 group was significantly lower than those in the IM6, IM9, and IM12 groups. The mean lesion depth in the IM12 group which showed the deepest lesion depth was 0.21 μm. As conclusions, the erosive lesion depth due to intake of carbonated soft drink was much shallower than remineralized enamel surface of a white spot lesion which can be repaired in plaque fluid in a short time, suggesting such erosion hardly causes tooth wear, hence it was suggested that brushing teeth just after the intake was recommended.
文摘An attempt was made to improve the adsorption capability of the normal sand to be used as adsorbent for phenol and cadmium This has been done by producing a coated sand media. The coating process was done using emulsion asphalt to convert the normal sand to carbonated sand by using chemical treatment with sulfuric acid. The production process involves mixing of the sand with asphalt and an acid, then subjecting the mix to a heating process. Different mixing ratios, heating temperatures and times （activation times） were tried to obtain the optimum conditions at which the highest removal efficiency is obtained. Three types of acids were tried acetic acid, phosphoric acid and sulfuric acid. It was found that the sulfuric acid requires the lowest activation time, hence selected for the production. The removal efficiency of the produced media was significantly affected by the temperature, mixing ratio and activation heating time. The results show that, the optimum conditions for the production process are 350 , （1：2：3） （Asphalt/acid/sand） and 52 min for temperature, mixing ratio and activation heating time respectively. The final product was tested and found effective as an adsorbent media for phenol and cadmium. The removal efficiencies of these two pollutants in a batch adsorber were found 82.42% and 86.67%, respectively. The X-R diffraction and FTIR spectra tests had proved this media as an adsorbent.
文摘A set of measurements have been conducted, using gamma spectrometry technique, in order to determine the activity-level in some carbonated soft drinks. The obtained activity is about 0.18 ± 0.07 Bq/l for <sup>137</sup>Cs, whereas it is less than 0.13, 0.18 and 4.51 Bq/l respectively for <sup>212</sup>Pb, <sup>214</sup>Pb and <sup>40</sup>K. The total average annual dose is about 3.49, 1.69 and 1.68 μSv/y respectively for 7 - 12, 12 - 17 and >17 years old person leading to a radiological risk about 0.142 for adolescent and adults. The obtained results show no significant radiation dose and radiation hazard on human health due to the consumption of these carbonated soft drinks.
