Carbon fibres have been produced from hydroxypropyl-modified lignin(TcC)/bio-based polyamide 1010(PA1010)blended filaments.Two grades of PA1010,with different molecular weights and rheological properties,were used for...Carbon fibres have been produced from hydroxypropyl-modified lignin(TcC)/bio-based polyamide 1010(PA1010)blended filaments.Two grades of PA1010,with different molecular weights and rheological properties,were used for blending with TcC.An oxidative thermal stabilisation step was used prior to carbonisation in an inert atmosphere to prevent the fusion of the filaments during the latter step.Thermal stabilisation was not possible using a one-step stabilisation process reported in the literature for lignin and other lignin/synthetic polymer blends.As a consequence,a cyclic process involving an additional isothermal phase at a lower temperature than the precursor filaments’melting point,was introduced to increase the cross-linking reactions between the lignin and polyamide.Thermally stabilised filaments were characterised by DSC,TGA,TGA-FTIR,ATR,and SEM techniques.Polymer rheology and heating rate used during thermal stabilisation influenced the thermal stabilisation process and mechanical properties of the derived filaments.Thermally stabilised filaments using optimised conditions(heating in the air atmosphere at 0.25℃/min to 180℃;isothermal for 1 h,cooling back down to ambient at 5℃/min;heating to 250℃ at 0.25℃/min,isothermal for 2 h)could be successfully carbonised.Carbon fibres pro-duced had void-free morphologies and mechanical properties comparable to similarly thermally stabilised and carbonised polyacrylonitrile(PAN)filaments.展开更多
Biochar,a solid carbonaceous material produced by heating biomass in oxygen-free or low-oxygen conditions(pyrolysis),has been used in various applications,including wastewater treatment,carbon sequestration,and improv...Biochar,a solid carbonaceous material produced by heating biomass in oxygen-free or low-oxygen conditions(pyrolysis),has been used in various applications,including wastewater treatment,carbon sequestration,and improving soil fertility.However,very limited research has been performed to explore its feasibility to improve the expansive clay(EC)subgrade.In this study,fine-grained wood biochar derived from wood waste was used to stabilise and enhance the mechanical performance of the EC as road subgrade.A comprehensive series of geotechnical tests,including unconfined compressive strength(UCS),California bearing ratio(CBR),repeated load triaxial(RLT),and swelling-shrinkage tests,were conducted to investigate the engineering properties of expansive clay mixed with different contents of the fine-grained biochar(FGB)(i.e.0,1%,2%,3%,and 4%by weight of dry soil).Furthermore,X-ray diffraction(XRD),X-ray fluorescence(XRF),X-ray micro-CT,and thermogravimetric analysis(TGA)analyses were performed to study the microchemical modification of the EC-FGB mixtures.The results showed that adding FGB reduced the swelling and shrinkage potential while enhancing the mechanical properties of the EC.The micro-level analysis also supported the enhancement of the geotechnical performance of the EC resulting from the incorporation of FGB.According to the test results,2%FGB was considered the optimum content,increasing UCS,CBR,and resilient modulus by 31.1%,24.1%,and 31.5%,respectively,and decreasing the swell-shrinkage index by 7%.展开更多
This study aims to investigate the feasibility of deriving in situ horizontal stresses from the breakout width and depth using the analytical method.Twenty-three breakout data with different borehole sizes were collec...This study aims to investigate the feasibility of deriving in situ horizontal stresses from the breakout width and depth using the analytical method.Twenty-three breakout data with different borehole sizes were collected and three failure criteria were studied.Based on the Kirsch equations,relatively accurate major horizontal stress(sH)estimations from known minor horizontal stress(sh)were achieved with percentage errors ranging from 0.33%to 44.08%using the breakout width.The Mogi-Coulomb failure criterion(average error:13.1%)outperformed modified Wiebols-Cook(average error:19.09%)and modified Lade(average error:18.09%)failure criteria.However,none of the tested constitutive models could yield reasonable sh predictions from known sH using the same approach due to the analytical expression of the redistributed stress and the nature of the constitutive models.In consideration of this issue,the horizontal stress ratio(sH/sh)is suggested as an alternative input,which could estimate both sH and sh with the same level of accuracy.Moreover,the estimation accuracies for both large-scale and laboratory-scale breakouts are comparable,suggesting the applicability of this approach across different breakout sizes.For breakout depth,conformal mapping and complex variable method were used to calculate the stress concentration around the breakout tip,allowing the expression of redistributed stresses using binomials composed of sH and sh.Nevertheless,analysis of the breakout depth stabilisation mechanism indicates that additional parameters are required to utilise normalised breakout depth for stress estimation compared to breakout width.These parameters are challenging to obtain,especially under field conditions,meaning utilising normalised breakout depth analytically in practical applications faces significant challenges and remains infeasible at this stage.Nonetheless,the normalised breakout depth should still be considered a critical input for any empirical and statistical stress estimation method given its significant correlation with horizontal stresses.The outcome of this paper is expected to contribute valuable insights into the breakout stabilisation mechanisms and estimation of in situ stress magnitudes based on borehole breakout geometries.展开更多
High-density lipoproteins （HDLs） have been well established to protect against the development of atherosclerotic cardiovascular disease. It has become apparent that in addition to the promotion of reverse cholester...High-density lipoproteins （HDLs） have been well established to protect against the development of atherosclerotic cardiovascular disease. It has become apparent that in addition to the promotion of reverse cholesterol transport, HDLs possess a number of additional functional properties that may contribute to their beneficial influence on the arterial wall. A number of exciting therapeutic strategies have been developed that target HDL and its ability to protect against the development of atherosclerotic plaque. This paper will review how the promotion of the functional properties of HDL inhibits the formation of atherosclerotic plaque and stabilises lesions in patients with established disease.展开更多
Expansive soils are problematic due to the performances of their clay mineral constituent, which makes them exhibit the shrink-swell characteristics. The shrink-swell behaviours make expansive soils inappropriate for ...Expansive soils are problematic due to the performances of their clay mineral constituent, which makes them exhibit the shrink-swell characteristics. The shrink-swell behaviours make expansive soils inappropriate for direct engineering application in their natural form. In an attempt to make them more feasible for construction purposes, numerous materials and techniques have been used to stabilise the soil. In this study, the additives and techniques applied for stabilising expansive soils will be focused on,with respect to their efficiency in improving the engineering properties of the soils. Then we discussed the microstructural interaction, chemical process, economic implication, nanotechnology application, as well as waste reuse and sustainability. Some issues regarding the effective application of the emerging trends in expansive soil stabilisation were presented with three categories, namely geoenvironmental,standardisation and optimisation issues. Techniques like predictive modelling and exploring methods such as reliability-based design optimisation, response surface methodology, dimensional analysis, and artificial intelligence technology were also proposed in order to ensure that expansive soil stabilisation is efficient.展开更多
Portland cement has been widely used for stabilisation/solidification （S/S） treatment of contaminated soils. However, there is a dearth of literature on pH-dependent leaching of contaminants from cement-treated soil...Portland cement has been widely used for stabilisation/solidification （S/S） treatment of contaminated soils. However, there is a dearth of literature on pH-dependent leaching of contaminants from cement-treated soils. This study investigates the leachability of Cu, Pb, Ni, Zn and total petroleum hydrocarbons （TPH） from a mixed contaminated soil. A sandy soil was spiked with 3000 mg/kg each of Cd, Cu, Pb, Ni and Zn, and 10,000 mg/kg of diesel, and treated with ordinary Portland cement （CEM I）. Four different binder dosages, 5%, 10%, 15% and 20% （m/m） and different water contents ranging from 13%-19% dry weight were used in order to find a safe operating envelope for the treatment process. The pH-dependent leaching behaviour of the treated soil was monitored over an 84-day period using a 3-point acid neutralisation capacity （ANC） test. The monolithic leaching test was also conducted. Geotechnical properties such as unconfined compressive strength （UCS）, hydraulic conductivity and porosity were assessed over time. The treated soils recorded lower leachate concentrations of Ni and Zn compared to the untreated soil at the same pH depending on binder dosage. The binder had problems with Pb stabilisation and TPH leachability was independent of pH and binder dosage. The hydraulic conductivity of the mixes was generally of the order, 10-8 m/sec, while the porosity ranged from 26%--44%. The results of selected performance properties are compared with regulatory limits and the range of operating variables that lead to acceptable performance described.展开更多
Dislocations of the sternoclavicular joint(SCJ) occur with relative infrequency and can be classified into anterior and posterior dislocation, with the former being more common. The SCJ is inherently unstable due to i...Dislocations of the sternoclavicular joint(SCJ) occur with relative infrequency and can be classified into anterior and posterior dislocation, with the former being more common. The SCJ is inherently unstable due to its lack of articular contact and therefore relies on stability from surrounding ligamentous structures, such as the costoclavicular, interclavicular and capsular ligaments. The posterior capsule has been shown in several studies to be the most important structure in determining stability irrespective of the direction of injury. Posterior dislocation of the SCJ can be associated with life threatening complications such as neurovascular, tracheal and oesophageal injuries. Due to the high mortality associated with such complications, these injuries need to be recognised acutely and managed promptly. Investigations such as x-ray imaging are poor at delineating anatomy at the level of the mediastinum and therefore CT imaging has become the investigation of choice. Due to its rarity, the current guidance on how to manage acute and chronic dislocations is debatable. This analysis of historical and recent literature aims to determine guidance on current thinking regarding SCJ instability, including the use of the Stanmore triangle. The described methods of reduction for both anterior and posterior dislocations and the various surgical reconstructive techniques are also discussed.展开更多
The precise diagnosis of distal tibiofibular syndesmotic ligament injury is challenging and a distinction should be made between syndesmotic ligament disruption and real syndesmotic instability.This article summarizes...The precise diagnosis of distal tibiofibular syndesmotic ligament injury is challenging and a distinction should be made between syndesmotic ligament disruption and real syndesmotic instability.This article summarizes the available evidence in the light of the author’s opinion.Pre-operative radiographic assessment,standard radiographs,computed tomography scanning and magnetic resonance imaging are of limited value in detecting syndesmotic instability in acute ankle fractures but can be helpful in planning.Intra-operative stress testing,in the sagittal,coronal or exorotation direction,is more reliable in the diagnosis of syndesmotic instability of rotational ankle fractures.The Hook or Cotton test is more reliable than the exorotation stress test.The lateral view is more reliable than the AP mortise view because of the larger displacement in this direction.When the Hook test is used the force should be applied in the sagittal direction.A force of 100 N applied to the fibula seems to be appropriate.In the case of an unstable joint requiring syndesmotic stabilisation,the tibiofibular clear space would exceed 5 mm on the lateral stress test.When the surgeon is able to perform an ankle arthroscopy this technique is useful to detect syndesmotic injury and can guide anatomic reduction of the syndesmosis.Many guidelines formulated in this article are based on biomechanical and cadaveric studies and clinical correlation has to be established.展开更多
An innovative in-situ stabilisation treatment followed by ex-situ sediment composting was tested for its ability to treat and dispose of heavy-metal-polluted sediments in a river near the Chinese Pearl Delta. First, p...An innovative in-situ stabilisation treatment followed by ex-situ sediment composting was tested for its ability to treat and dispose of heavy-metal-polluted sediments in a river near the Chinese Pearl Delta. First, polluted sediments were treated in-situ to stabilise the heavy metals. Then the treated sediments were dredged, dewatered and sent for high temperature aerobic composting （HTAC） treatment. Finally, the compost products were used as a fertiliser for fiver bank plants. The stabilisation efficiency of heavy metals during the process was investigated and the results are as follows： （1） using in-situ stabilisation, the extraction concentrations of Cu, Zn and Pb were reduced by 65.0%, 82.2% and 90.0%, respectively, which are much lower than the national standard given in the Identification Standard for Hazardous Waste （GB5085.3-1996）; （2） chemical fraction analysis showed that heavy metals were further stabilized during the HTAC treatment; （3） the concentrations of Cu, Zn and Pb in rainwater leachate through the river bank met the level of class V in the Environmental Quality Standards for Surface Water in China （GB3838-2002）. Therefore, using this new process, the toxicities of heavy metals in sediments were reduced markedly.展开更多
Replacement of TiH2 as foaming agent by CaCO3（lime） and CaMg（CO3）2（dolomite） for AlMg4.5-and AlSi9Cu3-foams was investigated considering inluences on foaming capability and cellular structure.Precursor materials...Replacement of TiH2 as foaming agent by CaCO3（lime） and CaMg（CO3）2（dolomite） for AlMg4.5-and AlSi9Cu3-foams was investigated considering inluences on foaming capability and cellular structure.Precursor materials were produced from alloy chip and powder mixtures by means of the thixocasting process.AlSi9Cu3 variants showed expansion levels suffcient for commercial use.Variations in expansion observed when CaCO3 and CaMg（CO3）2 were compared as foaming agent are explained based on the course of decomposition.Improved performance of dolomite-based foams relies on formation of stabilizing MgO phases,which do not develop during decomposition of CaCO3 in Al-Si-Cu alloys展开更多
High phosphorus(P)saturation arising from historic P inputs to protected vegetable fields(PVFs)drives high P mobilisation to waterbodies.Amendment of soils with alum has shown potential in terms of fixing labile P and...High phosphorus(P)saturation arising from historic P inputs to protected vegetable fields(PVFs)drives high P mobilisation to waterbodies.Amendment of soils with alum has shown potential in terms of fixing labile P and protecting water quality.The present 15 month pot experiment investigated P stabilisation across single alum application(Alum-1 treatment,20 g alum/kg soil incorporated into soil before the maize was sown),alum split applications(Alum-4 treatment,5 g alum/kg soil incorporated into soil before each crop was sown i.e.4×5 g/kg)and soil only treatment(Control).Results showed that the Alum-1 treatment caused the strongest stabilisation of soil labile P after maize plant removal,whereas the P stabilisation effect was gradually weakened due to the transformation of soil non-labile P to labile P and the reduced active Al^(3+)in soil solution.For the Alum-4 treatment,soil labile P decreased gradually with each crop planting and was lower than the Alum-1 treatment at the end of the final crop removal,without any impairment on plant growth.The better P stabilisation at the end of Alum-4 treatment was closely correlated with a progressive supply of Al^(3+)and a gradual decrease of pH,which resulted in higher contents of poorlycrystalline Al,Fe and exchangeable Ca.These aspects were conducive to increasing the soil P stabilisation and phosphate sorption.In terms of management,growers in continuous cropping systems could utilise split alum applications as a strategy to alleviate P losses in high-P enriched calcareous soil.展开更多
The mechanical performances and water retention characteristics of clays,stabilised by partial substitution of cement with by-products and inclusion of a nanotechnology-based additive called RoadCem(RC),are studied in...The mechanical performances and water retention characteristics of clays,stabilised by partial substitution of cement with by-products and inclusion of a nanotechnology-based additive called RoadCem(RC),are studied in this research.The unconfined compression tests and one-dimensional oedometer swelling were performed after 7 d of curing to understand the influence of addition of 1%of RC material in the stabilised soils with the cement partially replaced by 49%,59%and 69%of ground granulated blast furnace slag(GBBS)or pulverised fuel ash(PFA).The moisture retention capacity of the stabilised clays was also explored using the soil-water retention curve(SWRC)from the measured suctions.Results confirmed an obvious effect of the use of RC with the obtained strength and swell properties of the stabilised clays suitable for road application at 50%replacement of cement.This outcome is associated with the in-depth and penetrating hydration of the cementitious materials by the RC and water which results in the production of needle-like matrix with interlocking filaments e a phenomenon referred to as the‘wrapping’effect.On the other hand,the SWRC used to describe the water holding capacity and corresponding swell mechanism of clays stabilised by a proportion of RC showed a satisfactory response.The moisture retention of the RC-modified clays was initially higher but reduced subsequently as the saturation level increased with decreasing suction.This phenomenon confirmed that clays stabilised by including the RC are water-proof in nature,thus ensuring reduced porosity and suction even at reduced water content.Overall,the stabilised clays with the combination of cement,GGBS and RC showed a better performance compared to those with the PFA included.展开更多
Olivine sand is a natural mineral,which,when added to soil,can improve the soil’s mechanical properties while also sequester carbon dioxide(CO2)from the surrounding environment.The originality of this paper stems fro...Olivine sand is a natural mineral,which,when added to soil,can improve the soil’s mechanical properties while also sequester carbon dioxide(CO2)from the surrounding environment.The originality of this paper stems from the novel two-stage approach.In the first stage,natural carbonation of olivine and carbonation of olivine treated soil under different CO2pressures and times were investigated.In this stage,the unconfined compression test was used as a tool to evaluate the strength performance.In the second stage,details of the installation and performance of carbonated olivine columns using a laboratory-scale model were investigated.In this respect,olivine was mixed with the natural soil using the auger and the columns were then carbonated with gaseous CO2.The unconfined compressive strengths of soil in the first stage increased by up to 120% compared to those of the natural untreated soil.The strength development was found to be proportional to the CO2pressure and carbonation period.Microstructural analyses indicated the presence of magnesite on the surface of carbonated olivinetreated soil,demonstrating that modified physical properties provided a stronger and stiffer matrix.The performance of the carbonated olivine-soil columns,in terms of ultimate bearing capacity,showed that the carbonation procedure occurred rapidly and yielded a bearing capacity value of 120 k Pa.Results of this study are of significance to the construction industry as the feasibility of carbonated olivine for strengthening and stabilizing soil is validated.Its applicability lies in a range of different geotechnical applications whilst also mitigates the global warming through the sequestration of CO2.展开更多
Objective:To evaluate the effect of ethylacetate fraction(Fr-Et) and methanolic fraction(FrMe) obtained from Cressa cretica L.(C.crelica) L on experimental models for bronchodilatory activity and mast cell stabilising...Objective:To evaluate the effect of ethylacetate fraction(Fr-Et) and methanolic fraction(FrMe) obtained from Cressa cretica L.(C.crelica) L on experimental models for bronchodilatory activity and mast cell stabilising activity.Methods:The effect of Fr-Et and Fr-Me were studied on acetylcholine and histamine aerosol-induced broncospasm using guinea pigs as experimental animals.Also,the effects of these fractions were evaluated on the isolated guinea pig tracheal preparations.Besides this mast cell degranulation effect was assessed using egg albumin and compound 48/80 on rat peritoneal mast cells.Results:Significant increase in nreconvulsion time was observed due to pretrealment with the fractions when guinea pigs were exposed to histamine and acetylcholine aerosol.Fr-Et and Fr-Me significantly increased the preconvulsion in a dose depended manner that suggestive of bronchodilating activity.Fr-Et and Fr-Me exhibited a significant concentration dependant relaxant effect on guinea pig trachea pre-contracted with CCh,K^+ and histamine.The results revealed that Fr-Et to be more potent than Fr-Me in relaxing histamine and K^+ and calcium induced contraction than CCh induced conlractions.Studies on the fractions in protecting mast cell degranulation,which were elicited by the egg albumin as well as synthetic compound 48/80 revealed both the fractions significantly protect the mast cell degranulation,which release mediators such as histamine and proinflammatory cytokines through various stimuli in a dose depended manner.Conclusions:Thus our study established the bronchodilator activity,and mast cell stabilizing activity which are important mediators that provoke or sustain in asthma.展开更多
Waste stabilisation pond system has been used more especially in developing countries for sewage treatment. The objective of this study was to investigate the hydraulic and performance efficiency of Palapye waste stab...Waste stabilisation pond system has been used more especially in developing countries for sewage treatment. The objective of this study was to investigate the hydraulic and performance efficiency of Palapye waste stabilisation ponds. The hydraulic efficiency was evaluated through drogue, pond geometry and sludge accumulation assessment. The performance efficiency was evaluated through periodic sampling and analysis of physiochemical and bacteriological parameters of individual units and of the system as a whole. Except for the maturation ponds, the depth of the anaerobic pond had reduced from 4 m to 0.45 m, for facultative ponds from 2.0 m to a range of 0.52 m - 0.91 m. The design hydraulic retention time of the system had reduced from 20 days to 7.1 days. The concentration of some physiochemical parameters in the effluent was 305 mg·L-1, 277 Nephelometric Turbidity Units (NTU), 204 mg·L-1, 156 mg·L-1, 110 mg·L-1, and 15 mg·L-1 being total suspended solids, turbidity, nitrates, chemical oxygen demand, biochemical oxygen demand and phosphate respectively. These values were more than the standard limits of the country. Effluent total coliforms concentration was 3.6 log units and within the threshold of 4.3 log units, faecal coliforms concentration was 3.5 log units, slightly higher than the threshold of 3 log units. Though Escherichia coli have no limits for discharge into other environments, the concentration in the effluent was reasonable at 2.5 log units and also within irrigation limit of 3 log counts. Palapye wastewater treatment system hydraulic efficiency is lower than the design criterion. The system was overall poor in physiochemical parameters removal but better in bacteriological removal.展开更多
This paper proposes a case study in the control of a heavy oil pyrolysis/cracking furnace with a newly extended U-model based pole placement controller(U-PPC). The major work of the paper includes: 1) establishing a c...This paper proposes a case study in the control of a heavy oil pyrolysis/cracking furnace with a newly extended U-model based pole placement controller(U-PPC). The major work of the paper includes: 1) establishing a control oriented nonlinear dynamic model with Naphtha cracking and thermal dynamics; 2) analysing a U-model(i.e., control oriented prototype) representation of various popular process model sets; 3)designing the new U-PPC to enhance the control performance in pole placement and stabilisation; 4) taking computational bench tests to demonstrate the control system design and performance with a user-friendly step by step procedure.展开更多
Compost has been used to stabilise lead (Pb) in soil. However, compost contains a high level of dissolved organic matter (DOM) which may make Pb bioavailable in plant and thereby limiting its effectiveness and applica...Compost has been used to stabilise lead (Pb) in soil. However, compost contains a high level of dissolved organic matter (DOM) which may make Pb bioavailable in plant and thereby limiting its effectiveness and application. Addition of biochar to compost can reduce this effect. Rice husk (RH) and Cashew nut shell (CNS) biochars and compost-modified biochars were used in comparison to compost for stabilizing Pb in lead smelting slag (LSS)-contaminated soil (Pb = 18,300 mg/kg) in Nigeria. Efficiency of Pb stabilisation in control and amended soils was assessed using CaCl2 batch leaching experiment and plant performance. In pot experiments, maize plant was grown on the contaminated soil and on soil treated with minimum and optimum doses of the amendments singly and in combination for 6 weeks. Agronomical and chemical parameters of the plants were measured. CaCl2-extractable Pb in the untreated soil was reduced from 60 mg/kg to 0.55 mg/kg in RHB amended soils and non-detectable in other amended soils. RH-biochar/compost increased plant height, number of leaf and leaf area more than the others. Similarly, at minimum rate, it reduced root and shoot Pb by 91% and 86.0% respectively. Compost-modified rice husk biocharstabilised Pb in lead smelting slag contaminated soil reduced Pb plant uptake and improved plant growth. Lead stabilisation through the use of rice husk biochar with compost may be a green method for remediation of lead smelting slag-contaminated soil.展开更多
Compressed stabilized earth blocks are the innovation of building materials replacing the earth blocks commonly called adobe. Common stabilizers (cement and lime) have been found to be expensive and harmful to the env...Compressed stabilized earth blocks are the innovation of building materials replacing the earth blocks commonly called adobe. Common stabilizers (cement and lime) have been found to be expensive and harmful to the environment. Finding a natural, available, environmentally friendly stabilizer is vital. The objective of this study was therefore to assess the effects of gum Arabic (GA) as binder on the durability properties of laterite blocks. Compressed laterite blocks were stabilized with 2% and 6% respectively as total percentage of binders in the blocks (cement and/or GA). The results showed that GA improved the abrasion and drop resistances of compressed blocks. It has been found that the abrasion resistance of compressed blocks increased with the increase of GA content and the decrease of cement content. For instance, the mass abraded away of blocks stabilized with cement only was reduced up to 95.18% when GA was used to partially replace cement. As for drop test, the higher the content of GA the higher the resistance of blocks to drop.展开更多
Two kinetic models were established for conservative estimates of photodegradation rates of contaminants under sunlight irradiation,in particular for wastewater stabilisation ponds and clarifiers in conventional waste...Two kinetic models were established for conservative estimates of photodegradation rates of contaminants under sunlight irradiation,in particular for wastewater stabilisation ponds and clarifiers in conventional wastewater treatment plants.These two models were designated for(1)contaminants with high photolytic rates or high photolytic quantum yields,whose photodegradation is unlikely to be enhanced by aquatic photosensitisers;and(2)contaminants withstanding direct photolysis in sunlit waters but subjected to indirect photolysis.The effortlessly intelligible prediction procedure involves sampling and analysis of real water samples,simulated solar experiments in the laboratory,and transfer of the laboratory results to realise water treatment using the prediction models.Although similar models have been widely used for laboratory studies,this paper provides a preliminary example of translating laboratory results to the photochemical fate of contaminants in real waters.展开更多
Certain impurities of zircon sands, especially alumina, titania, calcia and yttria cannot be completely re- moved in the production of fused zirconia and may have an influence on the corrosion resistance and other pro...Certain impurities of zircon sands, especially alumina, titania, calcia and yttria cannot be completely re- moved in the production of fused zirconia and may have an influence on the corrosion resistance and other product properties of refractories for continuous casting of steel. In this paper, we present our findings on how impurities in raw materials end up in different stabilised zirconia refractory grains, in particular calcia-, magnesia- and yttria-stabilised zirconia. The microstructure （and phase composition） is affected by both the raw materials and the fusion conditions （furnace type and cooling technology）.展开更多
文摘Carbon fibres have been produced from hydroxypropyl-modified lignin(TcC)/bio-based polyamide 1010(PA1010)blended filaments.Two grades of PA1010,with different molecular weights and rheological properties,were used for blending with TcC.An oxidative thermal stabilisation step was used prior to carbonisation in an inert atmosphere to prevent the fusion of the filaments during the latter step.Thermal stabilisation was not possible using a one-step stabilisation process reported in the literature for lignin and other lignin/synthetic polymer blends.As a consequence,a cyclic process involving an additional isothermal phase at a lower temperature than the precursor filaments’melting point,was introduced to increase the cross-linking reactions between the lignin and polyamide.Thermally stabilised filaments were characterised by DSC,TGA,TGA-FTIR,ATR,and SEM techniques.Polymer rheology and heating rate used during thermal stabilisation influenced the thermal stabilisation process and mechanical properties of the derived filaments.Thermally stabilised filaments using optimised conditions(heating in the air atmosphere at 0.25℃/min to 180℃;isothermal for 1 h,cooling back down to ambient at 5℃/min;heating to 250℃ at 0.25℃/min,isothermal for 2 h)could be successfully carbonised.Carbon fibres pro-duced had void-free morphologies and mechanical properties comparable to similarly thermally stabilised and carbonised polyacrylonitrile(PAN)filaments.
基金supported by the Australian Research Council Training Centre for Whole Life Design of Carbon Neutral Infrastructure(Grant No.IC230100015).
文摘Biochar,a solid carbonaceous material produced by heating biomass in oxygen-free or low-oxygen conditions(pyrolysis),has been used in various applications,including wastewater treatment,carbon sequestration,and improving soil fertility.However,very limited research has been performed to explore its feasibility to improve the expansive clay(EC)subgrade.In this study,fine-grained wood biochar derived from wood waste was used to stabilise and enhance the mechanical performance of the EC as road subgrade.A comprehensive series of geotechnical tests,including unconfined compressive strength(UCS),California bearing ratio(CBR),repeated load triaxial(RLT),and swelling-shrinkage tests,were conducted to investigate the engineering properties of expansive clay mixed with different contents of the fine-grained biochar(FGB)(i.e.0,1%,2%,3%,and 4%by weight of dry soil).Furthermore,X-ray diffraction(XRD),X-ray fluorescence(XRF),X-ray micro-CT,and thermogravimetric analysis(TGA)analyses were performed to study the microchemical modification of the EC-FGB mixtures.The results showed that adding FGB reduced the swelling and shrinkage potential while enhancing the mechanical properties of the EC.The micro-level analysis also supported the enhancement of the geotechnical performance of the EC resulting from the incorporation of FGB.According to the test results,2%FGB was considered the optimum content,increasing UCS,CBR,and resilient modulus by 31.1%,24.1%,and 31.5%,respectively,and decreasing the swell-shrinkage index by 7%.
基金funded by the Australian Coal Industry’s Research Program(ACARP,Grant No.C26063).
文摘This study aims to investigate the feasibility of deriving in situ horizontal stresses from the breakout width and depth using the analytical method.Twenty-three breakout data with different borehole sizes were collected and three failure criteria were studied.Based on the Kirsch equations,relatively accurate major horizontal stress(sH)estimations from known minor horizontal stress(sh)were achieved with percentage errors ranging from 0.33%to 44.08%using the breakout width.The Mogi-Coulomb failure criterion(average error:13.1%)outperformed modified Wiebols-Cook(average error:19.09%)and modified Lade(average error:18.09%)failure criteria.However,none of the tested constitutive models could yield reasonable sh predictions from known sH using the same approach due to the analytical expression of the redistributed stress and the nature of the constitutive models.In consideration of this issue,the horizontal stress ratio(sH/sh)is suggested as an alternative input,which could estimate both sH and sh with the same level of accuracy.Moreover,the estimation accuracies for both large-scale and laboratory-scale breakouts are comparable,suggesting the applicability of this approach across different breakout sizes.For breakout depth,conformal mapping and complex variable method were used to calculate the stress concentration around the breakout tip,allowing the expression of redistributed stresses using binomials composed of sH and sh.Nevertheless,analysis of the breakout depth stabilisation mechanism indicates that additional parameters are required to utilise normalised breakout depth for stress estimation compared to breakout width.These parameters are challenging to obtain,especially under field conditions,meaning utilising normalised breakout depth analytically in practical applications faces significant challenges and remains infeasible at this stage.Nonetheless,the normalised breakout depth should still be considered a critical input for any empirical and statistical stress estimation method given its significant correlation with horizontal stresses.The outcome of this paper is expected to contribute valuable insights into the breakout stabilisation mechanisms and estimation of in situ stress magnitudes based on borehole breakout geometries.
文摘High-density lipoproteins （HDLs） have been well established to protect against the development of atherosclerotic cardiovascular disease. It has become apparent that in addition to the promotion of reverse cholesterol transport, HDLs possess a number of additional functional properties that may contribute to their beneficial influence on the arterial wall. A number of exciting therapeutic strategies have been developed that target HDL and its ability to protect against the development of atherosclerotic plaque. This paper will review how the promotion of the functional properties of HDL inhibits the formation of atherosclerotic plaque and stabilises lesions in patients with established disease.
文摘Expansive soils are problematic due to the performances of their clay mineral constituent, which makes them exhibit the shrink-swell characteristics. The shrink-swell behaviours make expansive soils inappropriate for direct engineering application in their natural form. In an attempt to make them more feasible for construction purposes, numerous materials and techniques have been used to stabilise the soil. In this study, the additives and techniques applied for stabilising expansive soils will be focused on,with respect to their efficiency in improving the engineering properties of the soils. Then we discussed the microstructural interaction, chemical process, economic implication, nanotechnology application, as well as waste reuse and sustainability. Some issues regarding the effective application of the emerging trends in expansive soil stabilisation were presented with three categories, namely geoenvironmental,standardisation and optimisation issues. Techniques like predictive modelling and exploring methods such as reliability-based design optimisation, response surface methodology, dimensional analysis, and artificial intelligence technology were also proposed in order to ensure that expansive soil stabilisation is efficient.
基金support the ProCeSS project,which was conducted by a consortium of five universities,led by University College London,and 17 industrial partners,under the UK DIUS Technology Strategy Board (TP/3/WMM/6/I/15611)
文摘Portland cement has been widely used for stabilisation/solidification （S/S） treatment of contaminated soils. However, there is a dearth of literature on pH-dependent leaching of contaminants from cement-treated soils. This study investigates the leachability of Cu, Pb, Ni, Zn and total petroleum hydrocarbons （TPH） from a mixed contaminated soil. A sandy soil was spiked with 3000 mg/kg each of Cd, Cu, Pb, Ni and Zn, and 10,000 mg/kg of diesel, and treated with ordinary Portland cement （CEM I）. Four different binder dosages, 5%, 10%, 15% and 20% （m/m） and different water contents ranging from 13%-19% dry weight were used in order to find a safe operating envelope for the treatment process. The pH-dependent leaching behaviour of the treated soil was monitored over an 84-day period using a 3-point acid neutralisation capacity （ANC） test. The monolithic leaching test was also conducted. Geotechnical properties such as unconfined compressive strength （UCS）, hydraulic conductivity and porosity were assessed over time. The treated soils recorded lower leachate concentrations of Ni and Zn compared to the untreated soil at the same pH depending on binder dosage. The binder had problems with Pb stabilisation and TPH leachability was independent of pH and binder dosage. The hydraulic conductivity of the mixes was generally of the order, 10-8 m/sec, while the porosity ranged from 26%--44%. The results of selected performance properties are compared with regulatory limits and the range of operating variables that lead to acceptable performance described.
文摘Dislocations of the sternoclavicular joint(SCJ) occur with relative infrequency and can be classified into anterior and posterior dislocation, with the former being more common. The SCJ is inherently unstable due to its lack of articular contact and therefore relies on stability from surrounding ligamentous structures, such as the costoclavicular, interclavicular and capsular ligaments. The posterior capsule has been shown in several studies to be the most important structure in determining stability irrespective of the direction of injury. Posterior dislocation of the SCJ can be associated with life threatening complications such as neurovascular, tracheal and oesophageal injuries. Due to the high mortality associated with such complications, these injuries need to be recognised acutely and managed promptly. Investigations such as x-ray imaging are poor at delineating anatomy at the level of the mediastinum and therefore CT imaging has become the investigation of choice. Due to its rarity, the current guidance on how to manage acute and chronic dislocations is debatable. This analysis of historical and recent literature aims to determine guidance on current thinking regarding SCJ instability, including the use of the Stanmore triangle. The described methods of reduction for both anterior and posterior dislocations and the various surgical reconstructive techniques are also discussed.
文摘The precise diagnosis of distal tibiofibular syndesmotic ligament injury is challenging and a distinction should be made between syndesmotic ligament disruption and real syndesmotic instability.This article summarizes the available evidence in the light of the author’s opinion.Pre-operative radiographic assessment,standard radiographs,computed tomography scanning and magnetic resonance imaging are of limited value in detecting syndesmotic instability in acute ankle fractures but can be helpful in planning.Intra-operative stress testing,in the sagittal,coronal or exorotation direction,is more reliable in the diagnosis of syndesmotic instability of rotational ankle fractures.The Hook or Cotton test is more reliable than the exorotation stress test.The lateral view is more reliable than the AP mortise view because of the larger displacement in this direction.When the Hook test is used the force should be applied in the sagittal direction.A force of 100 N applied to the fibula seems to be appropriate.In the case of an unstable joint requiring syndesmotic stabilisation,the tibiofibular clear space would exceed 5 mm on the lateral stress test.When the surgeon is able to perform an ankle arthroscopy this technique is useful to detect syndesmotic injury and can guide anatomic reduction of the syndesmosis.Many guidelines formulated in this article are based on biomechanical and cadaveric studies and clinical correlation has to be established.
基金supported by the Scientific and Tech- nological Planning Project of Guangdong Province (No. 2003A3040404)the Guangdong & Hong Kong Tech- nology Cooperation Funding (No. 2006A36702001)
文摘An innovative in-situ stabilisation treatment followed by ex-situ sediment composting was tested for its ability to treat and dispose of heavy-metal-polluted sediments in a river near the Chinese Pearl Delta. First, polluted sediments were treated in-situ to stabilise the heavy metals. Then the treated sediments were dredged, dewatered and sent for high temperature aerobic composting （HTAC） treatment. Finally, the compost products were used as a fertiliser for fiver bank plants. The stabilisation efficiency of heavy metals during the process was investigated and the results are as follows： （1） using in-situ stabilisation, the extraction concentrations of Cu, Zn and Pb were reduced by 65.0%, 82.2% and 90.0%, respectively, which are much lower than the national standard given in the Identification Standard for Hazardous Waste （GB5085.3-1996）; （2） chemical fraction analysis showed that heavy metals were further stabilized during the HTAC treatment; （3） the concentrations of Cu, Zn and Pb in rainwater leachate through the river bank met the level of class V in the Environmental Quality Standards for Surface Water in China （GB3838-2002）. Therefore, using this new process, the toxicities of heavy metals in sediments were reduced markedly.
文摘Replacement of TiH2 as foaming agent by CaCO3（lime） and CaMg（CO3）2（dolomite） for AlMg4.5-and AlSi9Cu3-foams was investigated considering inluences on foaming capability and cellular structure.Precursor materials were produced from alloy chip and powder mixtures by means of the thixocasting process.AlSi9Cu3 variants showed expansion levels suffcient for commercial use.Variations in expansion observed when CaCO3 and CaMg（CO3）2 were compared as foaming agent are explained based on the course of decomposition.Improved performance of dolomite-based foams relies on formation of stabilizing MgO phases,which do not develop during decomposition of CaCO3 in Al-Si-Cu alloys
基金supported by the National Key Research and Development Program of China(No.2016YFD0801006)the China Agriculture Research System(No.CARS-23-B16)。
文摘High phosphorus(P)saturation arising from historic P inputs to protected vegetable fields(PVFs)drives high P mobilisation to waterbodies.Amendment of soils with alum has shown potential in terms of fixing labile P and protecting water quality.The present 15 month pot experiment investigated P stabilisation across single alum application(Alum-1 treatment,20 g alum/kg soil incorporated into soil before the maize was sown),alum split applications(Alum-4 treatment,5 g alum/kg soil incorporated into soil before each crop was sown i.e.4×5 g/kg)and soil only treatment(Control).Results showed that the Alum-1 treatment caused the strongest stabilisation of soil labile P after maize plant removal,whereas the P stabilisation effect was gradually weakened due to the transformation of soil non-labile P to labile P and the reduced active Al^(3+)in soil solution.For the Alum-4 treatment,soil labile P decreased gradually with each crop planting and was lower than the Alum-1 treatment at the end of the final crop removal,without any impairment on plant growth.The better P stabilisation at the end of Alum-4 treatment was closely correlated with a progressive supply of Al^(3+)and a gradual decrease of pH,which resulted in higher contents of poorlycrystalline Al,Fe and exchangeable Ca.These aspects were conducive to increasing the soil P stabilisation and phosphate sorption.In terms of management,growers in continuous cropping systems could utilise split alum applications as a strategy to alleviate P losses in high-P enriched calcareous soil.
文摘The mechanical performances and water retention characteristics of clays,stabilised by partial substitution of cement with by-products and inclusion of a nanotechnology-based additive called RoadCem(RC),are studied in this research.The unconfined compression tests and one-dimensional oedometer swelling were performed after 7 d of curing to understand the influence of addition of 1%of RC material in the stabilised soils with the cement partially replaced by 49%,59%and 69%of ground granulated blast furnace slag(GBBS)or pulverised fuel ash(PFA).The moisture retention capacity of the stabilised clays was also explored using the soil-water retention curve(SWRC)from the measured suctions.Results confirmed an obvious effect of the use of RC with the obtained strength and swell properties of the stabilised clays suitable for road application at 50%replacement of cement.This outcome is associated with the in-depth and penetrating hydration of the cementitious materials by the RC and water which results in the production of needle-like matrix with interlocking filaments e a phenomenon referred to as the‘wrapping’effect.On the other hand,the SWRC used to describe the water holding capacity and corresponding swell mechanism of clays stabilised by a proportion of RC showed a satisfactory response.The moisture retention of the RC-modified clays was initially higher but reduced subsequently as the saturation level increased with decreasing suction.This phenomenon confirmed that clays stabilised by including the RC are water-proof in nature,thus ensuring reduced porosity and suction even at reduced water content.Overall,the stabilised clays with the combination of cement,GGBS and RC showed a better performance compared to those with the PFA included.
基金The financial support from Fundamental Research Grant Scheme(FRGS)entitled“sustainable soil stabilisation by olivineits mechanisms”funded by Ministry of Higher Education,Malaysia and Universiti Putra Malaysia(Project ID 93474-135837)
文摘Olivine sand is a natural mineral,which,when added to soil,can improve the soil’s mechanical properties while also sequester carbon dioxide(CO2)from the surrounding environment.The originality of this paper stems from the novel two-stage approach.In the first stage,natural carbonation of olivine and carbonation of olivine treated soil under different CO2pressures and times were investigated.In this stage,the unconfined compression test was used as a tool to evaluate the strength performance.In the second stage,details of the installation and performance of carbonated olivine columns using a laboratory-scale model were investigated.In this respect,olivine was mixed with the natural soil using the auger and the columns were then carbonated with gaseous CO2.The unconfined compressive strengths of soil in the first stage increased by up to 120% compared to those of the natural untreated soil.The strength development was found to be proportional to the CO2pressure and carbonation period.Microstructural analyses indicated the presence of magnesite on the surface of carbonated olivinetreated soil,demonstrating that modified physical properties provided a stronger and stiffer matrix.The performance of the carbonated olivine-soil columns,in terms of ultimate bearing capacity,showed that the carbonation procedure occurred rapidly and yielded a bearing capacity value of 120 k Pa.Results of this study are of significance to the construction industry as the feasibility of carbonated olivine for strengthening and stabilizing soil is validated.Its applicability lies in a range of different geotechnical applications whilst also mitigates the global warming through the sequestration of CO2.
文摘Objective:To evaluate the effect of ethylacetate fraction(Fr-Et) and methanolic fraction(FrMe) obtained from Cressa cretica L.(C.crelica) L on experimental models for bronchodilatory activity and mast cell stabilising activity.Methods:The effect of Fr-Et and Fr-Me were studied on acetylcholine and histamine aerosol-induced broncospasm using guinea pigs as experimental animals.Also,the effects of these fractions were evaluated on the isolated guinea pig tracheal preparations.Besides this mast cell degranulation effect was assessed using egg albumin and compound 48/80 on rat peritoneal mast cells.Results:Significant increase in nreconvulsion time was observed due to pretrealment with the fractions when guinea pigs were exposed to histamine and acetylcholine aerosol.Fr-Et and Fr-Me significantly increased the preconvulsion in a dose depended manner that suggestive of bronchodilating activity.Fr-Et and Fr-Me exhibited a significant concentration dependant relaxant effect on guinea pig trachea pre-contracted with CCh,K^+ and histamine.The results revealed that Fr-Et to be more potent than Fr-Me in relaxing histamine and K^+ and calcium induced contraction than CCh induced conlractions.Studies on the fractions in protecting mast cell degranulation,which were elicited by the egg albumin as well as synthetic compound 48/80 revealed both the fractions significantly protect the mast cell degranulation,which release mediators such as histamine and proinflammatory cytokines through various stimuli in a dose depended manner.Conclusions:Thus our study established the bronchodilator activity,and mast cell stabilizing activity which are important mediators that provoke or sustain in asthma.
文摘Waste stabilisation pond system has been used more especially in developing countries for sewage treatment. The objective of this study was to investigate the hydraulic and performance efficiency of Palapye waste stabilisation ponds. The hydraulic efficiency was evaluated through drogue, pond geometry and sludge accumulation assessment. The performance efficiency was evaluated through periodic sampling and analysis of physiochemical and bacteriological parameters of individual units and of the system as a whole. Except for the maturation ponds, the depth of the anaerobic pond had reduced from 4 m to 0.45 m, for facultative ponds from 2.0 m to a range of 0.52 m - 0.91 m. The design hydraulic retention time of the system had reduced from 20 days to 7.1 days. The concentration of some physiochemical parameters in the effluent was 305 mg·L-1, 277 Nephelometric Turbidity Units (NTU), 204 mg·L-1, 156 mg·L-1, 110 mg·L-1, and 15 mg·L-1 being total suspended solids, turbidity, nitrates, chemical oxygen demand, biochemical oxygen demand and phosphate respectively. These values were more than the standard limits of the country. Effluent total coliforms concentration was 3.6 log units and within the threshold of 4.3 log units, faecal coliforms concentration was 3.5 log units, slightly higher than the threshold of 3 log units. Though Escherichia coli have no limits for discharge into other environments, the concentration in the effluent was reasonable at 2.5 log units and also within irrigation limit of 3 log counts. Palapye wastewater treatment system hydraulic efficiency is lower than the design criterion. The system was overall poor in physiochemical parameters removal but better in bacteriological removal.
基金partially supported by the National Natural Science Foundation of China(61273188,61473312)Taishan Scholar Construction Engineering Special Funding of Shandong
文摘This paper proposes a case study in the control of a heavy oil pyrolysis/cracking furnace with a newly extended U-model based pole placement controller(U-PPC). The major work of the paper includes: 1) establishing a control oriented nonlinear dynamic model with Naphtha cracking and thermal dynamics; 2) analysing a U-model(i.e., control oriented prototype) representation of various popular process model sets; 3)designing the new U-PPC to enhance the control performance in pole placement and stabilisation; 4) taking computational bench tests to demonstrate the control system design and performance with a user-friendly step by step procedure.
文摘Compost has been used to stabilise lead (Pb) in soil. However, compost contains a high level of dissolved organic matter (DOM) which may make Pb bioavailable in plant and thereby limiting its effectiveness and application. Addition of biochar to compost can reduce this effect. Rice husk (RH) and Cashew nut shell (CNS) biochars and compost-modified biochars were used in comparison to compost for stabilizing Pb in lead smelting slag (LSS)-contaminated soil (Pb = 18,300 mg/kg) in Nigeria. Efficiency of Pb stabilisation in control and amended soils was assessed using CaCl2 batch leaching experiment and plant performance. In pot experiments, maize plant was grown on the contaminated soil and on soil treated with minimum and optimum doses of the amendments singly and in combination for 6 weeks. Agronomical and chemical parameters of the plants were measured. CaCl2-extractable Pb in the untreated soil was reduced from 60 mg/kg to 0.55 mg/kg in RHB amended soils and non-detectable in other amended soils. RH-biochar/compost increased plant height, number of leaf and leaf area more than the others. Similarly, at minimum rate, it reduced root and shoot Pb by 91% and 86.0% respectively. Compost-modified rice husk biocharstabilised Pb in lead smelting slag contaminated soil reduced Pb plant uptake and improved plant growth. Lead stabilisation through the use of rice husk biochar with compost may be a green method for remediation of lead smelting slag-contaminated soil.
文摘Compressed stabilized earth blocks are the innovation of building materials replacing the earth blocks commonly called adobe. Common stabilizers (cement and lime) have been found to be expensive and harmful to the environment. Finding a natural, available, environmentally friendly stabilizer is vital. The objective of this study was therefore to assess the effects of gum Arabic (GA) as binder on the durability properties of laterite blocks. Compressed laterite blocks were stabilized with 2% and 6% respectively as total percentage of binders in the blocks (cement and/or GA). The results showed that GA improved the abrasion and drop resistances of compressed blocks. It has been found that the abrasion resistance of compressed blocks increased with the increase of GA content and the decrease of cement content. For instance, the mass abraded away of blocks stabilized with cement only was reduced up to 95.18% when GA was used to partially replace cement. As for drop test, the higher the content of GA the higher the resistance of blocks to drop.
文摘Two kinetic models were established for conservative estimates of photodegradation rates of contaminants under sunlight irradiation,in particular for wastewater stabilisation ponds and clarifiers in conventional wastewater treatment plants.These two models were designated for(1)contaminants with high photolytic rates or high photolytic quantum yields,whose photodegradation is unlikely to be enhanced by aquatic photosensitisers;and(2)contaminants withstanding direct photolysis in sunlit waters but subjected to indirect photolysis.The effortlessly intelligible prediction procedure involves sampling and analysis of real water samples,simulated solar experiments in the laboratory,and transfer of the laboratory results to realise water treatment using the prediction models.Although similar models have been widely used for laboratory studies,this paper provides a preliminary example of translating laboratory results to the photochemical fate of contaminants in real waters.
文摘Certain impurities of zircon sands, especially alumina, titania, calcia and yttria cannot be completely re- moved in the production of fused zirconia and may have an influence on the corrosion resistance and other product properties of refractories for continuous casting of steel. In this paper, we present our findings on how impurities in raw materials end up in different stabilised zirconia refractory grains, in particular calcia-, magnesia- and yttria-stabilised zirconia. The microstructure （and phase composition） is affected by both the raw materials and the fusion conditions （furnace type and cooling technology）.
