Ammonium oxalate treatment, previously extensively studied on limestone in the laboratory, was applied to powdering historical stonework （limestone） situated on the shoreline in the Mediterranean Island of Malta. Th...Ammonium oxalate treatment, previously extensively studied on limestone in the laboratory, was applied to powdering historical stonework （limestone） situated on the shoreline in the Mediterranean Island of Malta. This paper presents the results obtained from onsite testing that aimed at evaluating the treatment in terms of its aesthetic performance, the depth of treatment, the mechanical properties of the consolidated stone and the influence on water transport. To this end, the testing program included colorimetry, DRMS （drilling resistance measurement system） and water absorption through the contact sponge method. This study is Part One of the final phase of a wider research program which included two previous phases progressing from treating this same very porous stone type in a laboratory-based controlled environment to uncontrolled site conditions, seeking to quantify this treatment＇s effectiveness in the field. Results showed that onsite consolidation was achieved and that although some changes in colour and water absorption were brought about by the treatment, these were within acceptable tolerance limits. Besides carrying out these treatments and evaluations directly on the coast, this study anticipates further studies which will look at rural and urban sites where the types and concentrations of salts are expected to be different.展开更多
A Geothermal Heat Pump (GHP) system is known to have enormous potential for building energy savings and the reduction of associated greenhouse gas emissions, due to its high Coefficient Of Performance (COP). The use o...A Geothermal Heat Pump (GHP) system is known to have enormous potential for building energy savings and the reduction of associated greenhouse gas emissions, due to its high Coefficient Of Performance (COP). The use of a GHP system in cold-climate regions is more attractive owing to its higher COP for heating compared to conventional heating devices, such as furnaces or boilers. Many factors, however, determine the operational performance of an existing GHP system, such as control strategy, part/full-load efficiency, the age of the system, defective parts, and whether or not regular maintenance services are provided. The omitting of any of these factors in design and operation stages could have significant impacts on the normal operation of GHP systems. Therefore, the objectives of this paper are to further investigate and study the existing GHP systems currently used in buildings located in cold-climate regions of the US, in terms of system operational performance, potential energy and energy cost savings, system cost information, the reasons for installing geothermal systems, current operating difficulties, and owner satisfaction to date. After the comprehensive investigation and in-depth analysis of 24 buildings, the results indicate that for these buildings, about 75% of the building owners are very satisfied with their GHP systems in terms of noise, cost, and indoor comfort. About 71% of the investigated GHP systems have not had serious operating difficulties, and about 85% of the respondents (building owners) would suggest this type of system to other people. Compared to the national median of energy use and energy cost of typical buildings of the same type nationwide, the overall performance of the actual GHP systems used in the cold-climate regions is slightly better, i.e. about 7.2% energy savings and 6.1% energy cost savings on average.展开更多
It is essential to determine the occurrence of emerging organic contaminants(EOCs),such as pharmaceuticals and personal care products(PPCPs),in the ambient environment to address growing public concerns.However,such a...It is essential to determine the occurrence of emerging organic contaminants(EOCs),such as pharmaceuticals and personal care products(PPCPs),in the ambient environment to address growing public concerns.However,such analysis is quite challenging due to the low trace level of such contaminants in water,which therefore requires several litres of water samples.In this study,a large volume solid phase extraction(LV-SPE)device was developed and evaluated for its performance in monitoring PPCPs as an example.Relatively good recoveries and reproducibility were obtained under specific operating conditions:a water sample volume of no more than 20 L,a flow rate not exceeding 120 mL/min,and a methanol elution volume of at least 30 mL.In addition,the results from the onsite enrichment approach using LV-SPE were compared with those from the conventional approach using a standard SPE device in the laboratory for real groundwater samples.Among the eight selected PPCPs(nalidixic acid,carbamazepine,bezafibrate,clofibric acid,sulfadiazine,sulfamethoxypyridazine,sulfamethazine and sulfamonomethoxine),LV-SPE approach detected more target compounds.While the detected concentrations were generally comparable,slightly higher concentrations were observed for carbamazepine,clofibric acid,sulfadiazine and sulfamethazine using the LV-SPE method.The developed LV-SPE device provides an alternative approach for trace analysis of PPCPs and may also be applicable for other emerging organic contaminants.展开更多
The feasibility of using anaerobic baffled reactor （ABR） as onsite wastewater treatment system was discussed. The ABR consisted of one sedimentation chamber and three up-flow chambers in series was experimented unde...The feasibility of using anaerobic baffled reactor （ABR） as onsite wastewater treatment system was discussed. The ABR consisted of one sedimentation chamber and three up-flow chambers in series was experimented under different peak flow factors （PFF of 1 to 6）, superficial gas velocities （between 0.6 and 3.1 cm/hr） and hydraulic retention times （HRT） （24, 36 and 48 hr）. Residence time distribution （RTD） analyses were carded out to investigate the hydraulic characteristics of the ABR. It was found that the PFF resulted in hydraulic dead space. The dead space did not exceed 13% at PFF of 1, 2 and 4 while there was 2-fold increase （26%） at PFF of 6. Superficial gas velocities did not result in more （biological） dead space. The mixing pattern of ABR tended to be a completely- mixed reactor when PFF increased. Superficial gas velocities did not affect mixing pattern. The effects of PFF on mixing pattern could be minimized by higher HRT （48 hr）. The tank-in-series （TIS） model （N = 4） was suitable to describe the hydraulic behaviour of the studied system. The HRT of 48 hr was able to maintain the mixing pattern under different flow patterns, introducing satisfactory hydraulic efficiency. Chemical oxygen demand （COD） and total suspended solids （TSS） removals under all flow patterns were achieved more than 85% and 90%, respectively. The standard deviation of effluent COD and TSS concentration did not exceed 15 mg/L.展开更多
A novel in-contact three-dimensional(3D)measuring device,called MultiCal,is proposed as a convenient,low-cost(less than US$5000),and robust facility for onsite kinematic calibration and online measurement of robot man...A novel in-contact three-dimensional(3D)measuring device,called MultiCal,is proposed as a convenient,low-cost(less than US$5000),and robust facility for onsite kinematic calibration and online measurement of robot manipulator accuracy.The device hasμm-level accuracy and can be easily embedded in robot cells.During the calibration procedure,the robot manipulator first moves automatically to multiple end-effector orientations with its tool center point(TCP)constrained on a fixed point by a 3D displacement measuring device(single point constraint),and the corresponding joint angles are recorded.Then,the measuring device is precisely mounted at different positions using a well-designed fixture,and the above measurement process is repeated to implement a multi-point constraint.The relative mounting positions are accurately measured and used as prior information to improve calibration accuracy and robustness.The results of theoretical analysis indicate that MultiCal reduces calibration accuracy by 10%to 20%in contrast to traditional non-contact 3D or six-dimensional(6D)measuring devices(such as laser trackers)when subject to the same level of artificial measurement noise.The results of a calibration experiment conducted on a Staubli TX90 robot show that MultiCal has only 7%to 14%lower calibration accuracy compared to a measuring arm with a laser scanner,and 21%to 30%lower time efficiency compared to a 6D binocular vision measuring system,yielding maximum and mean absolute position errors of 0.831 mm and 0.339 mm,respectively.展开更多
Typically, crude oil production in Nigeria always accompanied by surface production of associated gas. With little associated gas recovery facilities in place, majority of associated gas is continuously flared with fe...Typically, crude oil production in Nigeria always accompanied by surface production of associated gas. With little associated gas recovery facilities in place, majority of associated gas is continuously flared with few portions re-injected into the reservoir for enhance oil recovery (EOR). In addition to environmental hazards, wasting substantial amount of produced associated gas is deemed detrimental to a country currently generating less than 54% of its electric power requirement. Onsite power generation as one of the many means of utilization of associated gas has been conceived. Conversely, the availability and performance of the gas turbine engine for onsite associated gas utilization requires evaluation owing to variations in associated natural gas composition globally and the dependency of associated gas production on reservoirs and oil production activities. This paper presents an analytical investigation of gas turbine engine inspired by GE LMS100 frame engine for onsite utilization of associated gas in Nigeria. Gas turbine performance results are presented and performance parameters are compared against typical commercial natural gas grade.展开更多
This study was performed to evaluate the efficacy of the Demolizer? technology for the on-site sterilization of low vo-lumes of regulated medical waste. The objective was to demonstrate a minimum of 6 log10 reduction ...This study was performed to evaluate the efficacy of the Demolizer? technology for the on-site sterilization of low vo-lumes of regulated medical waste. The objective was to demonstrate a minimum of 6 log10 reduction of the dry heat sterilization process applied by the Demolizer? II system for the representative organisms, Staphylococcus aureus, Escherichia coli, Candida albicans, Mycobacterium phlei and Bacillus subtilis spores (formerly Bacillus subtilis) on simulated medical waste consistent with numerous regulatory standards for medical waste treatment. The system cycle was heat treatment at a minimum temperature of 350?F and held at or above this temperature for a minimum of 90 minutes. Upon completion of treatment, there was no evidence of growth in the bacterial species after treatment. Given the minimum detection level of 4 CFU/ml, the Demolizer? II system demonstrated a minimum sterilization efficacy of 6.6 log10 for both S. aureus and E. coli as representative gram-positive and gram-negative bacteria species. Candida albicans (6.7 log10 CFU/ml), Mycobacterium phlei (9.0 log10 CFU/ml) and Bacillus subtilis (6.3 log10 CFU/ml) were completely eliminated after sterilizing representative medical waste in the Demolizer? II system for 90 minutes at a minimum temperature of 350?F. Also, the Demolizer? II exceeded typical recognized standards for medical waste treatment of a 6 log10 reduction of Mycobacteria and a 4 log10 reduction of the appropriate Bacillus endospore.展开更多
文摘Ammonium oxalate treatment, previously extensively studied on limestone in the laboratory, was applied to powdering historical stonework （limestone） situated on the shoreline in the Mediterranean Island of Malta. This paper presents the results obtained from onsite testing that aimed at evaluating the treatment in terms of its aesthetic performance, the depth of treatment, the mechanical properties of the consolidated stone and the influence on water transport. To this end, the testing program included colorimetry, DRMS （drilling resistance measurement system） and water absorption through the contact sponge method. This study is Part One of the final phase of a wider research program which included two previous phases progressing from treating this same very porous stone type in a laboratory-based controlled environment to uncontrolled site conditions, seeking to quantify this treatment＇s effectiveness in the field. Results showed that onsite consolidation was achieved and that although some changes in colour and water absorption were brought about by the treatment, these were within acceptable tolerance limits. Besides carrying out these treatments and evaluations directly on the coast, this study anticipates further studies which will look at rural and urban sites where the types and concentrations of salts are expected to be different.
文摘A Geothermal Heat Pump (GHP) system is known to have enormous potential for building energy savings and the reduction of associated greenhouse gas emissions, due to its high Coefficient Of Performance (COP). The use of a GHP system in cold-climate regions is more attractive owing to its higher COP for heating compared to conventional heating devices, such as furnaces or boilers. Many factors, however, determine the operational performance of an existing GHP system, such as control strategy, part/full-load efficiency, the age of the system, defective parts, and whether or not regular maintenance services are provided. The omitting of any of these factors in design and operation stages could have significant impacts on the normal operation of GHP systems. Therefore, the objectives of this paper are to further investigate and study the existing GHP systems currently used in buildings located in cold-climate regions of the US, in terms of system operational performance, potential energy and energy cost savings, system cost information, the reasons for installing geothermal systems, current operating difficulties, and owner satisfaction to date. After the comprehensive investigation and in-depth analysis of 24 buildings, the results indicate that for these buildings, about 75% of the building owners are very satisfied with their GHP systems in terms of noise, cost, and indoor comfort. About 71% of the investigated GHP systems have not had serious operating difficulties, and about 85% of the respondents (building owners) would suggest this type of system to other people. Compared to the national median of energy use and energy cost of typical buildings of the same type nationwide, the overall performance of the actual GHP systems used in the cold-climate regions is slightly better, i.e. about 7.2% energy savings and 6.1% energy cost savings on average.
基金This research was financially supported by the Major Science and Technology Program for Water Pollution Control and Treatment in China(Grant No.2017ZX07202004).
文摘It is essential to determine the occurrence of emerging organic contaminants(EOCs),such as pharmaceuticals and personal care products(PPCPs),in the ambient environment to address growing public concerns.However,such analysis is quite challenging due to the low trace level of such contaminants in water,which therefore requires several litres of water samples.In this study,a large volume solid phase extraction(LV-SPE)device was developed and evaluated for its performance in monitoring PPCPs as an example.Relatively good recoveries and reproducibility were obtained under specific operating conditions:a water sample volume of no more than 20 L,a flow rate not exceeding 120 mL/min,and a methanol elution volume of at least 30 mL.In addition,the results from the onsite enrichment approach using LV-SPE were compared with those from the conventional approach using a standard SPE device in the laboratory for real groundwater samples.Among the eight selected PPCPs(nalidixic acid,carbamazepine,bezafibrate,clofibric acid,sulfadiazine,sulfamethoxypyridazine,sulfamethazine and sulfamonomethoxine),LV-SPE approach detected more target compounds.While the detected concentrations were generally comparable,slightly higher concentrations were observed for carbamazepine,clofibric acid,sulfadiazine and sulfamethazine using the LV-SPE method.The developed LV-SPE device provides an alternative approach for trace analysis of PPCPs and may also be applicable for other emerging organic contaminants.
基金supported by the Swiss National Centre of Competence in Research (NCCR) North-South:Research Partnerships for Mitigating Syndromes of Global Change, and the Swiss National Science Foundation and the Swiss Agency for Development and Cooperation
文摘The feasibility of using anaerobic baffled reactor （ABR） as onsite wastewater treatment system was discussed. The ABR consisted of one sedimentation chamber and three up-flow chambers in series was experimented under different peak flow factors （PFF of 1 to 6）, superficial gas velocities （between 0.6 and 3.1 cm/hr） and hydraulic retention times （HRT） （24, 36 and 48 hr）. Residence time distribution （RTD） analyses were carded out to investigate the hydraulic characteristics of the ABR. It was found that the PFF resulted in hydraulic dead space. The dead space did not exceed 13% at PFF of 1, 2 and 4 while there was 2-fold increase （26%） at PFF of 6. Superficial gas velocities did not result in more （biological） dead space. The mixing pattern of ABR tended to be a completely- mixed reactor when PFF increased. Superficial gas velocities did not affect mixing pattern. The effects of PFF on mixing pattern could be minimized by higher HRT （48 hr）. The tank-in-series （TIS） model （N = 4） was suitable to describe the hydraulic behaviour of the studied system. The HRT of 48 hr was able to maintain the mixing pattern under different flow patterns, introducing satisfactory hydraulic efficiency. Chemical oxygen demand （COD） and total suspended solids （TSS） removals under all flow patterns were achieved more than 85% and 90%, respectively. The standard deviation of effluent COD and TSS concentration did not exceed 15 mg/L.
基金Project supported by the Key R&D Program of Zhejiang Province,China(No.2022C04030)the National Key R&D Program of China(Nos.2020YFB1313300 and 2018AAA0102703)the National Natural Science Foundation of China(No.61836015)。
文摘A novel in-contact three-dimensional(3D)measuring device,called MultiCal,is proposed as a convenient,low-cost(less than US$5000),and robust facility for onsite kinematic calibration and online measurement of robot manipulator accuracy.The device hasμm-level accuracy and can be easily embedded in robot cells.During the calibration procedure,the robot manipulator first moves automatically to multiple end-effector orientations with its tool center point(TCP)constrained on a fixed point by a 3D displacement measuring device(single point constraint),and the corresponding joint angles are recorded.Then,the measuring device is precisely mounted at different positions using a well-designed fixture,and the above measurement process is repeated to implement a multi-point constraint.The relative mounting positions are accurately measured and used as prior information to improve calibration accuracy and robustness.The results of theoretical analysis indicate that MultiCal reduces calibration accuracy by 10%to 20%in contrast to traditional non-contact 3D or six-dimensional(6D)measuring devices(such as laser trackers)when subject to the same level of artificial measurement noise.The results of a calibration experiment conducted on a Staubli TX90 robot show that MultiCal has only 7%to 14%lower calibration accuracy compared to a measuring arm with a laser scanner,and 21%to 30%lower time efficiency compared to a 6D binocular vision measuring system,yielding maximum and mean absolute position errors of 0.831 mm and 0.339 mm,respectively.
文摘Typically, crude oil production in Nigeria always accompanied by surface production of associated gas. With little associated gas recovery facilities in place, majority of associated gas is continuously flared with few portions re-injected into the reservoir for enhance oil recovery (EOR). In addition to environmental hazards, wasting substantial amount of produced associated gas is deemed detrimental to a country currently generating less than 54% of its electric power requirement. Onsite power generation as one of the many means of utilization of associated gas has been conceived. Conversely, the availability and performance of the gas turbine engine for onsite associated gas utilization requires evaluation owing to variations in associated natural gas composition globally and the dependency of associated gas production on reservoirs and oil production activities. This paper presents an analytical investigation of gas turbine engine inspired by GE LMS100 frame engine for onsite utilization of associated gas in Nigeria. Gas turbine performance results are presented and performance parameters are compared against typical commercial natural gas grade.
文摘This study was performed to evaluate the efficacy of the Demolizer? technology for the on-site sterilization of low vo-lumes of regulated medical waste. The objective was to demonstrate a minimum of 6 log10 reduction of the dry heat sterilization process applied by the Demolizer? II system for the representative organisms, Staphylococcus aureus, Escherichia coli, Candida albicans, Mycobacterium phlei and Bacillus subtilis spores (formerly Bacillus subtilis) on simulated medical waste consistent with numerous regulatory standards for medical waste treatment. The system cycle was heat treatment at a minimum temperature of 350?F and held at or above this temperature for a minimum of 90 minutes. Upon completion of treatment, there was no evidence of growth in the bacterial species after treatment. Given the minimum detection level of 4 CFU/ml, the Demolizer? II system demonstrated a minimum sterilization efficacy of 6.6 log10 for both S. aureus and E. coli as representative gram-positive and gram-negative bacteria species. Candida albicans (6.7 log10 CFU/ml), Mycobacterium phlei (9.0 log10 CFU/ml) and Bacillus subtilis (6.3 log10 CFU/ml) were completely eliminated after sterilizing representative medical waste in the Demolizer? II system for 90 minutes at a minimum temperature of 350?F. Also, the Demolizer? II exceeded typical recognized standards for medical waste treatment of a 6 log10 reduction of Mycobacteria and a 4 log10 reduction of the appropriate Bacillus endospore.
