We explore the entanglement features of pure symmetric N-qubit states characterized by N-distinct spinors with a particular focus on the Greenberger-Horne-Zeilinger (GHZ) states and , an equal superposition of W and o...We explore the entanglement features of pure symmetric N-qubit states characterized by N-distinct spinors with a particular focus on the Greenberger-Horne-Zeilinger (GHZ) states and , an equal superposition of W and obverse W states. Along with a comparison of pairwise entanglement and monogamy properties, we explore the geometric information contained in them by constructing their canonical steering ellipsoids. We obtain the volume monogamy relations satisfied by states as a function of number of qubits and compare with the maximal monogamy property of GHZ states.展开更多
The study evaluated the effectiveness of honey dressings in healing recent skin wounds with soft tissue loss on limbs. Conducted over a year with 60 patients, results showed a significant reduction in wound size and e...The study evaluated the effectiveness of honey dressings in healing recent skin wounds with soft tissue loss on limbs. Conducted over a year with 60 patients, results showed a significant reduction in wound size and early healing, with complete recovery on average within 29 days. The study supports honey as a viable wound treatment.展开更多
Hippopotamus bites are rare in medical consultations, despite several studies exposing their aggressive character. A case of a hippopotamus bite on the shoulder of a fisherman has been reported. In addition to the ost...Hippopotamus bites are rare in medical consultations, despite several studies exposing their aggressive character. A case of a hippopotamus bite on the shoulder of a fisherman has been reported. In addition to the osteoarticular aspect representing a therapeutic problem, the infectious aspect was marked by sepsis, with a death in less than 48 hours. Based on this observation, a protocol for the initial management of large animal bites was submitted.展开更多
The distribution of the various organic and inorganic constituents and their influences on the combustion of coal has been comprehensively studied.However,the combustion characteristics of pulverized coal depend not o...The distribution of the various organic and inorganic constituents and their influences on the combustion of coal has been comprehensively studied.However,the combustion characteristics of pulverized coal depend not only on rank but also on the composition,distribution,and combination of the macerals.Unlike the proximate and ultimate analyses,determining the macerals in coal involves the use of sophisticated microscopic instrumentation and expertise.In this study,an attempt was made to predict the amount of macerals(vitrinite,inertinite,and liptinite)and total mineral matter from the Witbank Coalfields samples using the multiple input single output white-box artificial neural network(MISOWB-ANN),gene expression programming(GEP),multiple linear regression(MLR),and multiple nonlinear regression(MNLR).The predictive models obtained from the multiple soft computing models adopted are contrasted with one another using difference,efficiency,and composite statistical indicators to examine the appropriateness of the models.The MISOWB-ANN provides a more reliable predictive model than the other three models with the lowest difference and highest efficiency and composite statistical indicators.展开更多
The spontaneous combustion liability of coal can be determined by using different experimental techniques.These techniques are well-known in their application,but no certain test method has become a standard to prove ...The spontaneous combustion liability of coal can be determined by using different experimental techniques.These techniques are well-known in their application,but no certain test method has become a standard to prove the reliability of all of them.A general characterisation which included proximate and ultimate analyses,petrographic properties and spontaneous combustion tests(thermogravimetric analysis(TGA)and the Wits-Ehac tests)were conducted on fourteen coal and four coal-shale samples.The spontaneous combustion liability of these samples collected between coal seams(above and below)were predicted using the TGA and the Wits-Ehac tests.Six different heating rates(3,6,9,15,20 and 25C/min)were selected based on the deviation coefficient to obtain different derivative slopes and a liability index termed the TGspc index.This study found that coal and coal-shale undergo spontaneous combustion between coal seams when exposed to oxygen in the air.Their intrinsic properties and proneness towards spontaneous combustion differ considerably from one seam to the other.The Wits-Ehac test results agreed with the TGspc results to a certain extent and revealed the incidents of spontaneous combustion in the coal mines.展开更多
Objectives:The study aimed to evaluate quality of nephrolithometric nomograms to predict stone-free rates(SFRs)and complication rates(CRs)in case of minimally invasive percutaneous nephrolithotomy(PNL).In the last dec...Objectives:The study aimed to evaluate quality of nephrolithometric nomograms to predict stone-free rates(SFRs)and complication rates(CRs)in case of minimally invasive percutaneous nephrolithotomy(PNL).In the last decade,nomograms have been introduced to estimate the SFRs and CRs of PNL.However,no data are available regarding their reliability in case of utilization of miniaturized devices.Herein we present a prospective multicentric study to evaluate reliability of Guy’s stone score(GSS),the stone size,tract length,obstruction,number of involved calyces,and essence of stone(S.T.O.N.E.)nephrolithometry score and Clinical Research Office of the Endourological Society(CROES)score in patients treated with minimally invasive PNL.Methods:We evaluated SFRs and CRs of 222 adult patients treated with miniaturized PNL.Patients were considered stone-free if no residual fragments of any size at post-operative unenhanced computed tomography scan.Patients demographics,SFRs,and CRs were reported and analyzed.Performances of nomograms were evaluated with the area under the curve(AUC).Results:We included 222 patients,the AUCs of GSS,CROES score,and S.T.O.N.E.nephrolithometry score were 0.69(95%confidence interval[CI]0.61-0.78),0.64(95%CI 0.56-0.73),and 0.62(95%CI 0.52-0.71),respectively.Regarding SFRs,at multivariate binomial logistic regression,only the GSS had significance with an odds ratio of 0.53(95%CI 0.31e0.95,p=0.04).We did not find significant correlation with complications,with only a trend for GSS.Conclusion:This is the first study evaluating nomograms in miniaturized PNL.They still show good reliability;however,our data showed lower performances compared to standard PNL.We emphasize the need of further studies to confirm this trend.A dedicated nomogram for minimally invasive PNL may be necessary.展开更多
Hydrothermal carbonization(HTC)technologies for producing value-added carbonaceous material(hydrochar)from coal waste and sewage sludge(SS)waste might be a long-term recycling strategy for hydrogen storage application...Hydrothermal carbonization(HTC)technologies for producing value-added carbonaceous material(hydrochar)from coal waste and sewage sludge(SS)waste might be a long-term recycling strategy for hydrogen storage applications,cutting disposal costs and solving waste disposal difficulties.In this study,hydrochars(HC)with high carbon content were produced using a combination of optimal HTC(HTC and Co-HTC)and chemical activation of coal tailings(CT),coal slurry(CS),and a mixture of coal discard and sewage sludge(CB).At 850℃and 800℃,respectively,with a KOH/HC ratio of 4:1 and a residence time of 135 min,activated carbons(ACs)with the highest Brunauer–Emmett–Teller specific surface(S_(BET))of 2299.25 m^(2)g^(−1)and 2243.57 m^(2)g^(−1)were obtained.The hydrogen adsorption capability of the produced ACs was further studied using gas adsorption isotherms at 77 K.At 35 bars,the values of hydrogen adsorbed onto AC-HCT(AC obtained from HTC of CT),AC-HCS(AC obtained from HTC of CS),and AC-HCB(AC obtained from HTC of the blending of coal discard(CD)and SS)were approximately 6.12%,6.8%,and 6.57%in weight,respectively.Furthermore,the cost of producing synthetic ACs for hydrogen storage is equivalent to the cost of commercial carbons.Furthermore,the high proportion of carbon retained(>70%)in ACs synthesized by HTC from CD and SS precursors should restrict their potential carbon emissions.展开更多
The concentration of phosphate flotation concentrate with P2O5 grade lower than the commercially acceptable phosphate quality was upgraded in the use of tribo-electrostatic technique. The concentration of the flotatio...The concentration of phosphate flotation concentrate with P2O5 grade lower than the commercially acceptable phosphate quality was upgraded in the use of tribo-electrostatic technique. The concentration of the flotation concentrate stream was conducted under both triboelectrification and inductive charging mechanism. Mineralogical analysis reveals that the phosphate ore utilized was dominated mainly by fluorapatite, crandallite, wavellite, and with quartz as the major gangue mineral. Flotations concentrate of about 28.87% P2O5 was obtained from the reverse flotation technique, after conditioning the phosphate ore at 80% passing 150 lm under Lilafloat. Constant parameters such as à6 kV charging voltage, 25 kV separating voltage, inlet air, different charger rotary speed and splitter distances were investigated. Commercially accepted grade of 35.50% P2O5 was attained after the second stage of separation with a recovery of 12.26%, another phosphate product of 34.02% P2O5 and 85.19% was also recovered under the same condition. Single stage of separation also shows a significant increase in the grade of the product obtained, with 33.41% P2O5 and 84.07% recovery achievable. The practicability of tribo-electrostatic separation technique for upgrading flotation concentrates resulted in a significant increase in grade for <150 lm product that do not meet the viable grade.展开更多
Introduction: Neglected ankle fractures are common in our regions. Patients first consult traditional healers and it is when the signs persist that they consult the surgeon for a swollen and painful ankle. Initially w...Introduction: Neglected ankle fractures are common in our regions. Patients first consult traditional healers and it is when the signs persist that they consult the surgeon for a swollen and painful ankle. Initially we always performed anatomical repairs with osteosynthesis, but the majority of patients still complained of pain and disability. We wondered whether a primary arthrodesis would not be indicated in old ankle fractures to avoid disabling pain for patients. We therefore performed a series of arthrodesis on neglected post-traumatic ankles. The objective of our study was to describe the results of arthrodesis on an old post-traumatic ankle and to propose a therapeutic indication in the face of any neglected ankle fracture. Material and Method: This was a prospective study over 8 years between December 2012 and November 2020, involving 36 cases of neglected ankle fractures treated by arthrodesis using Meary’s technique. We used AOFAS (American Orthopedic Foot and Ankle Score) preoperatively and postoperatively for an objective assessment. Results: The average follow-up was 4.2 years and our results were satisfactory (94.4%) with an average AOFAS score ranging from 27.8 preoperatively to 76.7 postoperatively. The fusion rate was 97.2%. Discussion: Arthrodesis appears here as an important alternative in the treatment of neglected ankle fractures with significant trophic disorders.展开更多
Introduction: Neglected elbow dislocations are much more common in developing and underdeveloped countries. The main reason for the delay in diagnosis is that patients initially seek treatment from traditional healers...Introduction: Neglected elbow dislocations are much more common in developing and underdeveloped countries. The main reason for the delay in diagnosis is that patients initially seek treatment from traditional healers. These will immobilize the elbow in extension, which will lead to the retraction of the triceps muscle and collateral ligaments. Patients and Method: We carried out a prospective study over five years (2014-2019). The study involved patients with unreduced elbow dislocation older than 21 days. All patients with a dislocated fracture and those whose x-ray showed joint fusion were not included in the study. We collected 26 patients, 20 men and 6 women with an average age of 27.5 years (17 and 45 years). The average consultation time was 8.9 months (3 - 13). The approach was posterior about 8 cm above the olecranon and 2 cm below the olecranon, the ulnar nerve was identified and isolated. The triceps tendon was cut in a Z from its myotendin junction to the beak of the olecranon, and then lengthened. Results: The patients were reviewed after a mean follow-up of 24 months (12 - 36). The Mayo Clinic’s average elbow performance index was 77.1 (60 - 85), with 19 good and 6 average results. The mean flexion was 114°(100°- 135°) and the mean extension deficit was 31.15°(10°- 55°). The average range of motion was 82.5°(60°- 120°). We did not find a correlation between the duration of the lesion and functional recovery (p > 0.05). The Wilcoxon test showed that surgery significantly improved the overall range of motion of the elbow (p = 0.001). Discussion: Based on this study, open reduction with tendon lengthening should remain a treatment option regardless of the age and chronicity of the dislocation.展开更多
In this work, a theory based on the steady photoconductivity method, of a bifacial silicon solar cell under polychromatic illumination and a magnetic field effect, is presented. The resolution of the continuity equati...In this work, a theory based on the steady photoconductivity method, of a bifacial silicon solar cell under polychromatic illumination and a magnetic field effect, is presented. The resolution of the continuity equation in the base of the solar cell, allowed us to establish the expression of the minority carriers’ density from which the photoconductivity, the photocurrent density, the photovoltage and the solar output power as function of the junction recombination velocity and the applied magnetic field, were deduced. From I-V and P-V characteristics of the solar cell, optimal photovoltage and optimal photocurrent obtained at the maximum power point corresponding to a given operating point which is correlated to an optimal junction recombination velocity, were determined according to the magnetic field. By means of the relation between the photocurrent density and the photoconductivity, the junction electric field has been determined at a given optimal junction recombination velocity.展开更多
Emergency debridement has long been the standard of care for open fractures of the tibia as infection is an important complication. In developing countries, patients are admitted to teaching hospitals 6 to 24 hours af...Emergency debridement has long been the standard of care for open fractures of the tibia as infection is an important complication. In developing countries, patients are admitted to teaching hospitals 6 to 24 hours after their initial trauma. We sought to evaluate outcomes of nailing and correlations between the risk of infection and the delay in surgery. Materials and methods: Medical files of 48 men and 15 women with a combined total of 63 open fractures of the leg during a 12-year period were reviewed. The mean age was 29 years. Thirty-four type I and 29 type II open fractures according to the classification of Cauchoix and Duparc were treated with Küntscher nail after excision/debridement. Preoperative CRP was performed in 27 patients and in 22 cases it was positive. Twenty-six fractures were treated within a period of 6 to 24 hours, and a further 37 was operated on beyond 24 hours. The average waiting time before surgery was 2 days. Results: The infection was present in 11 patients (17.5%). We failed to establish any correlation between the time of treatment and the occurrence of infection for both type I and type II fractures treated during the same intervals with p = 0.244 (p > 0.05). But we established a correlation between the type of open fracture and the occurrence of infection with p = 0.01 (p < 0.05). There were 10 cases of infection among 22 cases of positive preoperative CRP. We couldn’t find a correlation between the positive value of the preoperative CRP and the occurrence of infection. Seven cases of infection were treated with appropriate antibiotherapy and early revision surgery. Four others cases complicated to bone infection (n = 2) and septic nonunion (n = 2). The average time of hospitalization was 22 days. The average time for fracture healing was 7 months. Conclusion: The rule of six hours is hardly applicable in our contexts. Our study showed no correlation between the preoperative period and the occurrence of infection.展开更多
Lacking in literature is the use of discard coal to produce activated carbon and in its subsequent use in the storage of natural gas. In this study, the characterization and gas storage evaluation of a largely porous ...Lacking in literature is the use of discard coal to produce activated carbon and in its subsequent use in the storage of natural gas. In this study, the characterization and gas storage evaluation of a largely porous activated carbon with large surface area synthesized from discard coal were investigated. Discard coals are waste material generated from coal beneficiation process. In developing the activated carbon, chemical activation route with the use of KOH reagent was applied. The effects of KOH/discard coal weight ratio (1:1, 2.5:1, 4:1), temperature (400-800 ℃) and particle size (0.15-0.25 mm, 0.25-0.5 mm, 0.5-1 mm) on the adsorptive properties of the activated carbon were methodically evaluated and optimized using response surface methodology. The synthesized activated carbon was characterized using BET, SEM/EDS, and XRD. The results showed that for each activation process, the surface area and pore volume of the resulting activated carbon increased with increased temperature and KOH/discard coal weight ratio. The maximum surface area of 1826.41 m2/g, pore volume of 1.252 cm^3/g and pore size of 2.77 nm were obtained at carbonization temperature of 800 ℃ and KOH/discard coal weight ratio of 4:1. Methane and nitrogen adsorption data at high pressure were fitted to Toth isotherm model with a predictive accuracy of about 99%. Adsorption parameters using the Toth model provides useful information in the design of adsorbed natural gas storage system. According to the requirements of adsorbent desired for natural gas storage, it could be stated that the synthesized activated carbon could well be applied for natural gas storage.展开更多
A Longi LGS 500 wet high intensity magnetic separator(WHIMS) was used to concentrate a fine, low grade South African hematite ore. The ore was prepared into different size fractions and was subjected to changes in pul...A Longi LGS 500 wet high intensity magnetic separator(WHIMS) was used to concentrate a fine, low grade South African hematite ore. The ore was prepared into different size fractions and was subjected to changes in pulp density, magnetic field intensity and pulsation frequency which followed a 33 full factorial matrix. The concentrate mass yield and Fe grade were selected as the dependent responses to the changes. The analysis of variance(ANOVA) shows that the variables investigated are significant to the material's response to magnetic separation. This significance was in the order of magnetic field intensity followed by pulsation frequency and then pulp density. It was also noted that a single stage magnetic separation has a potential to upgrade a feed( 75 lm and 40% Fe) to a 55% Fe grade, as the pulsation frequency increases. In addition, the model predictions and actual data were in good agreement, reporting regression coefficients within acceptable ranges.展开更多
The elemental composition of coal and biomass provides significant parameters used in the design of almost all energy conversion systems and projects.The laboratory tests to determine the elemental composition of coal...The elemental composition of coal and biomass provides significant parameters used in the design of almost all energy conversion systems and projects.The laboratory tests to determine the elemental composition of coal and biomass is time-consuming and costly.However,limited research has suggested that there is a correlation between parameters obtained from elemental and proximate analyses of these materials.In this study,some predictive models of the elemental composition of coal and biomass using soft computing and regression analyses have been developed.Thirty-one samples including parameters of elemental and proximate analyses were used during the analyses to develop multiple prediction models.Dependent variables for multiple prediction models were selected as carbon,hydrogen,and oxygen.Using volatile matter,fixed carbon,moisture and ash contents as independent variables,three different prediction models were developed for each dependent parameter using ANFIS,ANN,and MLR.In addition,a routine for selecting the best predictive model was suggested in the study.The reliability of the established models was tested by using various prediction performance indices and the models were found to be satisfactory.Therefore,the developed models can be used to determine the elemental composition of coal and biomass for practical purposes.展开更多
The fact that water requirements are a major problem for present and future developments in material beneficiation, and the construction of a new power plant in South Africa, forms the basis for the utilization of a R...The fact that water requirements are a major problem for present and future developments in material beneficiation, and the construction of a new power plant in South Africa, forms the basis for the utilization of a Rotary Triboelectrostatic Separator (RTS) for beneficiation of South African pulverized coal. The cleaning potential of Majuba and Koorfontein coal was first evaluated using kinetic froth flotation tests on the -177 μm coal fraction. The RTS tests were conducted under varied process parameters. Parameters such as applied separating voltage, air injection velocity, particle feed rate and splitter position were investigated. Two stage separation results show that the RTS reduced Majuba coal initially containing about 30% ash to a clean product of 14.30%, or 19.46%, ash at a combustible recovery of 15.10%, or 53.02%, respectively. Similar separation performance was also achieved with the Koorfontein coal. The mineral and organic compositions in the feed, after single stage and after the second stage separations were characterized using X-ray diffraction analysis. The results show a better separation for the second stage coal products.展开更多
There is an increasing global concern for adverse effects of inorganic fertilizer and pesticides applied to agricultural soils. This study investigated metal speciation in soil and health risk assessment of Jute mallo...There is an increasing global concern for adverse effects of inorganic fertilizer and pesticides applied to agricultural soils. This study investigated metal speciation in soil and health risk assessment of Jute mallow (Corchorus olitoriuos) from a farm settlement in Ikorodu, Lagos State. Soil samples were collected according to the set standard procedure, sequentially extracted and analyzed for selected heavy metals using standard methods. Results showed that chromium (Cr) was associated with reducible fraction (Fe-Mn) for top soil, while cadmium (Cd), manganese (Mn), and copper (Cu);lead (Pb) and nickel (Ni);and Cr were predominantly bound to carbonate, reducible and residual mineral components respectively for sub-soil. The results of Contamination Factor (CF), Contamination Degree (CD), Pollution Load Index (PLI) and Geoaccumulation Index (Igeo) showed that the soil samples were not polluted for all the investigated metals. The Cd level in the soil (13.54 ± 1.21 mg·kg﹣1) and vegetables (0.83 ± 0.05 mg·kg﹣1) were above the USEPA critical permissible limit of 3.0 mg·kg﹣1 and 0.1 - 1.2 mg·kg﹣1 respectively. The daily intake of estimated selected heavy metals from the vegetable ranged from 8.8 × 10﹣03 to 1.4 × 10﹣02 for adult and 3.8 × 10﹣03 to 1.1 × 10﹣02 for children while the Hazard Quotient (HQ) for adults ranged from 5.4 × 10﹣05 to 1.1 × 10﹣01 and that of children ranged from 8.3 × 10﹣03 to 1.4 × 10﹣02. The cancer risk (CR) values of heavy metals in the soil ranged from 1.02 × 10﹣11 to 9.90展开更多
文摘We explore the entanglement features of pure symmetric N-qubit states characterized by N-distinct spinors with a particular focus on the Greenberger-Horne-Zeilinger (GHZ) states and , an equal superposition of W and obverse W states. Along with a comparison of pairwise entanglement and monogamy properties, we explore the geometric information contained in them by constructing their canonical steering ellipsoids. We obtain the volume monogamy relations satisfied by states as a function of number of qubits and compare with the maximal monogamy property of GHZ states.
文摘The study evaluated the effectiveness of honey dressings in healing recent skin wounds with soft tissue loss on limbs. Conducted over a year with 60 patients, results showed a significant reduction in wound size and early healing, with complete recovery on average within 29 days. The study supports honey as a viable wound treatment.
文摘Hippopotamus bites are rare in medical consultations, despite several studies exposing their aggressive character. A case of a hippopotamus bite on the shoulder of a fisherman has been reported. In addition to the osteoarticular aspect representing a therapeutic problem, the infectious aspect was marked by sepsis, with a death in less than 48 hours. Based on this observation, a protocol for the initial management of large animal bites was submitted.
文摘The distribution of the various organic and inorganic constituents and their influences on the combustion of coal has been comprehensively studied.However,the combustion characteristics of pulverized coal depend not only on rank but also on the composition,distribution,and combination of the macerals.Unlike the proximate and ultimate analyses,determining the macerals in coal involves the use of sophisticated microscopic instrumentation and expertise.In this study,an attempt was made to predict the amount of macerals(vitrinite,inertinite,and liptinite)and total mineral matter from the Witbank Coalfields samples using the multiple input single output white-box artificial neural network(MISOWB-ANN),gene expression programming(GEP),multiple linear regression(MLR),and multiple nonlinear regression(MNLR).The predictive models obtained from the multiple soft computing models adopted are contrasted with one another using difference,efficiency,and composite statistical indicators to examine the appropriateness of the models.The MISOWB-ANN provides a more reliable predictive model than the other three models with the lowest difference and highest efficiency and composite statistical indicators.
文摘The spontaneous combustion liability of coal can be determined by using different experimental techniques.These techniques are well-known in their application,but no certain test method has become a standard to prove the reliability of all of them.A general characterisation which included proximate and ultimate analyses,petrographic properties and spontaneous combustion tests(thermogravimetric analysis(TGA)and the Wits-Ehac tests)were conducted on fourteen coal and four coal-shale samples.The spontaneous combustion liability of these samples collected between coal seams(above and below)were predicted using the TGA and the Wits-Ehac tests.Six different heating rates(3,6,9,15,20 and 25C/min)were selected based on the deviation coefficient to obtain different derivative slopes and a liability index termed the TGspc index.This study found that coal and coal-shale undergo spontaneous combustion between coal seams when exposed to oxygen in the air.Their intrinsic properties and proneness towards spontaneous combustion differ considerably from one seam to the other.The Wits-Ehac test results agreed with the TGspc results to a certain extent and revealed the incidents of spontaneous combustion in the coal mines.
文摘Objectives:The study aimed to evaluate quality of nephrolithometric nomograms to predict stone-free rates(SFRs)and complication rates(CRs)in case of minimally invasive percutaneous nephrolithotomy(PNL).In the last decade,nomograms have been introduced to estimate the SFRs and CRs of PNL.However,no data are available regarding their reliability in case of utilization of miniaturized devices.Herein we present a prospective multicentric study to evaluate reliability of Guy’s stone score(GSS),the stone size,tract length,obstruction,number of involved calyces,and essence of stone(S.T.O.N.E.)nephrolithometry score and Clinical Research Office of the Endourological Society(CROES)score in patients treated with minimally invasive PNL.Methods:We evaluated SFRs and CRs of 222 adult patients treated with miniaturized PNL.Patients were considered stone-free if no residual fragments of any size at post-operative unenhanced computed tomography scan.Patients demographics,SFRs,and CRs were reported and analyzed.Performances of nomograms were evaluated with the area under the curve(AUC).Results:We included 222 patients,the AUCs of GSS,CROES score,and S.T.O.N.E.nephrolithometry score were 0.69(95%confidence interval[CI]0.61-0.78),0.64(95%CI 0.56-0.73),and 0.62(95%CI 0.52-0.71),respectively.Regarding SFRs,at multivariate binomial logistic regression,only the GSS had significance with an odds ratio of 0.53(95%CI 0.31e0.95,p=0.04).We did not find significant correlation with complications,with only a trend for GSS.Conclusion:This is the first study evaluating nomograms in miniaturized PNL.They still show good reliability;however,our data showed lower performances compared to standard PNL.We emphasize the need of further studies to confirm this trend.A dedicated nomogram for minimally invasive PNL may be necessary.
文摘Hydrothermal carbonization(HTC)technologies for producing value-added carbonaceous material(hydrochar)from coal waste and sewage sludge(SS)waste might be a long-term recycling strategy for hydrogen storage applications,cutting disposal costs and solving waste disposal difficulties.In this study,hydrochars(HC)with high carbon content were produced using a combination of optimal HTC(HTC and Co-HTC)and chemical activation of coal tailings(CT),coal slurry(CS),and a mixture of coal discard and sewage sludge(CB).At 850℃and 800℃,respectively,with a KOH/HC ratio of 4:1 and a residence time of 135 min,activated carbons(ACs)with the highest Brunauer–Emmett–Teller specific surface(S_(BET))of 2299.25 m^(2)g^(−1)and 2243.57 m^(2)g^(−1)were obtained.The hydrogen adsorption capability of the produced ACs was further studied using gas adsorption isotherms at 77 K.At 35 bars,the values of hydrogen adsorbed onto AC-HCT(AC obtained from HTC of CT),AC-HCS(AC obtained from HTC of CS),and AC-HCB(AC obtained from HTC of the blending of coal discard(CD)and SS)were approximately 6.12%,6.8%,and 6.57%in weight,respectively.Furthermore,the cost of producing synthetic ACs for hydrogen storage is equivalent to the cost of commercial carbons.Furthermore,the high proportion of carbon retained(>70%)in ACs synthesized by HTC from CD and SS precursors should restrict their potential carbon emissions.
基金the financial support of the South African National Energy Research Institute(SANERI)the Mineral Processing Division, Mintek
文摘The concentration of phosphate flotation concentrate with P2O5 grade lower than the commercially acceptable phosphate quality was upgraded in the use of tribo-electrostatic technique. The concentration of the flotation concentrate stream was conducted under both triboelectrification and inductive charging mechanism. Mineralogical analysis reveals that the phosphate ore utilized was dominated mainly by fluorapatite, crandallite, wavellite, and with quartz as the major gangue mineral. Flotations concentrate of about 28.87% P2O5 was obtained from the reverse flotation technique, after conditioning the phosphate ore at 80% passing 150 lm under Lilafloat. Constant parameters such as à6 kV charging voltage, 25 kV separating voltage, inlet air, different charger rotary speed and splitter distances were investigated. Commercially accepted grade of 35.50% P2O5 was attained after the second stage of separation with a recovery of 12.26%, another phosphate product of 34.02% P2O5 and 85.19% was also recovered under the same condition. Single stage of separation also shows a significant increase in the grade of the product obtained, with 33.41% P2O5 and 84.07% recovery achievable. The practicability of tribo-electrostatic separation technique for upgrading flotation concentrates resulted in a significant increase in grade for <150 lm product that do not meet the viable grade.
文摘Introduction: Neglected ankle fractures are common in our regions. Patients first consult traditional healers and it is when the signs persist that they consult the surgeon for a swollen and painful ankle. Initially we always performed anatomical repairs with osteosynthesis, but the majority of patients still complained of pain and disability. We wondered whether a primary arthrodesis would not be indicated in old ankle fractures to avoid disabling pain for patients. We therefore performed a series of arthrodesis on neglected post-traumatic ankles. The objective of our study was to describe the results of arthrodesis on an old post-traumatic ankle and to propose a therapeutic indication in the face of any neglected ankle fracture. Material and Method: This was a prospective study over 8 years between December 2012 and November 2020, involving 36 cases of neglected ankle fractures treated by arthrodesis using Meary’s technique. We used AOFAS (American Orthopedic Foot and Ankle Score) preoperatively and postoperatively for an objective assessment. Results: The average follow-up was 4.2 years and our results were satisfactory (94.4%) with an average AOFAS score ranging from 27.8 preoperatively to 76.7 postoperatively. The fusion rate was 97.2%. Discussion: Arthrodesis appears here as an important alternative in the treatment of neglected ankle fractures with significant trophic disorders.
文摘Introduction: Neglected elbow dislocations are much more common in developing and underdeveloped countries. The main reason for the delay in diagnosis is that patients initially seek treatment from traditional healers. These will immobilize the elbow in extension, which will lead to the retraction of the triceps muscle and collateral ligaments. Patients and Method: We carried out a prospective study over five years (2014-2019). The study involved patients with unreduced elbow dislocation older than 21 days. All patients with a dislocated fracture and those whose x-ray showed joint fusion were not included in the study. We collected 26 patients, 20 men and 6 women with an average age of 27.5 years (17 and 45 years). The average consultation time was 8.9 months (3 - 13). The approach was posterior about 8 cm above the olecranon and 2 cm below the olecranon, the ulnar nerve was identified and isolated. The triceps tendon was cut in a Z from its myotendin junction to the beak of the olecranon, and then lengthened. Results: The patients were reviewed after a mean follow-up of 24 months (12 - 36). The Mayo Clinic’s average elbow performance index was 77.1 (60 - 85), with 19 good and 6 average results. The mean flexion was 114°(100°- 135°) and the mean extension deficit was 31.15°(10°- 55°). The average range of motion was 82.5°(60°- 120°). We did not find a correlation between the duration of the lesion and functional recovery (p > 0.05). The Wilcoxon test showed that surgery significantly improved the overall range of motion of the elbow (p = 0.001). Discussion: Based on this study, open reduction with tendon lengthening should remain a treatment option regardless of the age and chronicity of the dislocation.
文摘In this work, a theory based on the steady photoconductivity method, of a bifacial silicon solar cell under polychromatic illumination and a magnetic field effect, is presented. The resolution of the continuity equation in the base of the solar cell, allowed us to establish the expression of the minority carriers’ density from which the photoconductivity, the photocurrent density, the photovoltage and the solar output power as function of the junction recombination velocity and the applied magnetic field, were deduced. From I-V and P-V characteristics of the solar cell, optimal photovoltage and optimal photocurrent obtained at the maximum power point corresponding to a given operating point which is correlated to an optimal junction recombination velocity, were determined according to the magnetic field. By means of the relation between the photocurrent density and the photoconductivity, the junction electric field has been determined at a given optimal junction recombination velocity.
文摘Emergency debridement has long been the standard of care for open fractures of the tibia as infection is an important complication. In developing countries, patients are admitted to teaching hospitals 6 to 24 hours after their initial trauma. We sought to evaluate outcomes of nailing and correlations between the risk of infection and the delay in surgery. Materials and methods: Medical files of 48 men and 15 women with a combined total of 63 open fractures of the leg during a 12-year period were reviewed. The mean age was 29 years. Thirty-four type I and 29 type II open fractures according to the classification of Cauchoix and Duparc were treated with Küntscher nail after excision/debridement. Preoperative CRP was performed in 27 patients and in 22 cases it was positive. Twenty-six fractures were treated within a period of 6 to 24 hours, and a further 37 was operated on beyond 24 hours. The average waiting time before surgery was 2 days. Results: The infection was present in 11 patients (17.5%). We failed to establish any correlation between the time of treatment and the occurrence of infection for both type I and type II fractures treated during the same intervals with p = 0.244 (p > 0.05). But we established a correlation between the type of open fracture and the occurrence of infection with p = 0.01 (p < 0.05). There were 10 cases of infection among 22 cases of positive preoperative CRP. We couldn’t find a correlation between the positive value of the preoperative CRP and the occurrence of infection. Seven cases of infection were treated with appropriate antibiotherapy and early revision surgery. Four others cases complicated to bone infection (n = 2) and septic nonunion (n = 2). The average time of hospitalization was 22 days. The average time for fracture healing was 7 months. Conclusion: The rule of six hours is hardly applicable in our contexts. Our study showed no correlation between the preoperative period and the occurrence of infection.
文摘Lacking in literature is the use of discard coal to produce activated carbon and in its subsequent use in the storage of natural gas. In this study, the characterization and gas storage evaluation of a largely porous activated carbon with large surface area synthesized from discard coal were investigated. Discard coals are waste material generated from coal beneficiation process. In developing the activated carbon, chemical activation route with the use of KOH reagent was applied. The effects of KOH/discard coal weight ratio (1:1, 2.5:1, 4:1), temperature (400-800 ℃) and particle size (0.15-0.25 mm, 0.25-0.5 mm, 0.5-1 mm) on the adsorptive properties of the activated carbon were methodically evaluated and optimized using response surface methodology. The synthesized activated carbon was characterized using BET, SEM/EDS, and XRD. The results showed that for each activation process, the surface area and pore volume of the resulting activated carbon increased with increased temperature and KOH/discard coal weight ratio. The maximum surface area of 1826.41 m2/g, pore volume of 1.252 cm^3/g and pore size of 2.77 nm were obtained at carbonization temperature of 800 ℃ and KOH/discard coal weight ratio of 4:1. Methane and nitrogen adsorption data at high pressure were fitted to Toth isotherm model with a predictive accuracy of about 99%. Adsorption parameters using the Toth model provides useful information in the design of adsorbed natural gas storage system. According to the requirements of adsorbent desired for natural gas storage, it could be stated that the synthesized activated carbon could well be applied for natural gas storage.
基金NRF SARCh I Clean Coal Technology, Mintek – South Africa and the University of the Witwatersrand for making funds available for the research study
文摘A Longi LGS 500 wet high intensity magnetic separator(WHIMS) was used to concentrate a fine, low grade South African hematite ore. The ore was prepared into different size fractions and was subjected to changes in pulp density, magnetic field intensity and pulsation frequency which followed a 33 full factorial matrix. The concentrate mass yield and Fe grade were selected as the dependent responses to the changes. The analysis of variance(ANOVA) shows that the variables investigated are significant to the material's response to magnetic separation. This significance was in the order of magnetic field intensity followed by pulsation frequency and then pulp density. It was also noted that a single stage magnetic separation has a potential to upgrade a feed( 75 lm and 40% Fe) to a 55% Fe grade, as the pulsation frequency increases. In addition, the model predictions and actual data were in good agreement, reporting regression coefficients within acceptable ranges.
文摘The elemental composition of coal and biomass provides significant parameters used in the design of almost all energy conversion systems and projects.The laboratory tests to determine the elemental composition of coal and biomass is time-consuming and costly.However,limited research has suggested that there is a correlation between parameters obtained from elemental and proximate analyses of these materials.In this study,some predictive models of the elemental composition of coal and biomass using soft computing and regression analyses have been developed.Thirty-one samples including parameters of elemental and proximate analyses were used during the analyses to develop multiple prediction models.Dependent variables for multiple prediction models were selected as carbon,hydrogen,and oxygen.Using volatile matter,fixed carbon,moisture and ash contents as independent variables,three different prediction models were developed for each dependent parameter using ANFIS,ANN,and MLR.In addition,a routine for selecting the best predictive model was suggested in the study.The reliability of the established models was tested by using various prediction performance indices and the models were found to be satisfactory.Therefore,the developed models can be used to determine the elemental composition of coal and biomass for practical purposes.
基金the financial support of the South African National Energy Research Institute (SANERI)
文摘The fact that water requirements are a major problem for present and future developments in material beneficiation, and the construction of a new power plant in South Africa, forms the basis for the utilization of a Rotary Triboelectrostatic Separator (RTS) for beneficiation of South African pulverized coal. The cleaning potential of Majuba and Koorfontein coal was first evaluated using kinetic froth flotation tests on the -177 μm coal fraction. The RTS tests were conducted under varied process parameters. Parameters such as applied separating voltage, air injection velocity, particle feed rate and splitter position were investigated. Two stage separation results show that the RTS reduced Majuba coal initially containing about 30% ash to a clean product of 14.30%, or 19.46%, ash at a combustible recovery of 15.10%, or 53.02%, respectively. Similar separation performance was also achieved with the Koorfontein coal. The mineral and organic compositions in the feed, after single stage and after the second stage separations were characterized using X-ray diffraction analysis. The results show a better separation for the second stage coal products.
文摘There is an increasing global concern for adverse effects of inorganic fertilizer and pesticides applied to agricultural soils. This study investigated metal speciation in soil and health risk assessment of Jute mallow (Corchorus olitoriuos) from a farm settlement in Ikorodu, Lagos State. Soil samples were collected according to the set standard procedure, sequentially extracted and analyzed for selected heavy metals using standard methods. Results showed that chromium (Cr) was associated with reducible fraction (Fe-Mn) for top soil, while cadmium (Cd), manganese (Mn), and copper (Cu);lead (Pb) and nickel (Ni);and Cr were predominantly bound to carbonate, reducible and residual mineral components respectively for sub-soil. The results of Contamination Factor (CF), Contamination Degree (CD), Pollution Load Index (PLI) and Geoaccumulation Index (Igeo) showed that the soil samples were not polluted for all the investigated metals. The Cd level in the soil (13.54 ± 1.21 mg·kg﹣1) and vegetables (0.83 ± 0.05 mg·kg﹣1) were above the USEPA critical permissible limit of 3.0 mg·kg﹣1 and 0.1 - 1.2 mg·kg﹣1 respectively. The daily intake of estimated selected heavy metals from the vegetable ranged from 8.8 × 10﹣03 to 1.4 × 10﹣02 for adult and 3.8 × 10﹣03 to 1.1 × 10﹣02 for children while the Hazard Quotient (HQ) for adults ranged from 5.4 × 10﹣05 to 1.1 × 10﹣01 and that of children ranged from 8.3 × 10﹣03 to 1.4 × 10﹣02. The cancer risk (CR) values of heavy metals in the soil ranged from 1.02 × 10﹣11 to 9.90
