Muhammad Asif Khan, Muhammad Waseem Khan, Asima Siddique
The climate variations have lot of the financial, medical and economic consequences. Studies showed that climate plays the vital role in virus transmission. This study analyzed the impact of climate indicators on COVID-19 concerning Pakistan. The secondary data is used for analysis as obtained from world health organization, ministry of health Pakistan and Pakistan meteorological department. The results show that all the research variables like temperature maximum, temperature minimum, humidity, and wind flow are positively and significantly correlated to COVID-19. Findings show that temperature maximum, temperature minimum, and wind flow have the positive and significant association with COVID-19, while the humidity has a positive impact on COVID-19 transmission. The study show that minimum temperature is favorable for the virus transmission. Thus, the study provides significant results in reaching the decision and concluding the study.
{"title":"IS CLIMATE INDICATOR AFFECTS TRANSMISSION OF COVID-19 PANDEMIC: CLIMATIC IMPACTS ON COVID-19 TRANSMISSION","authors":"Muhammad Asif Khan, Muhammad Waseem Khan, Asima Siddique","doi":"10.51380/GUJR-37-01-04","DOIUrl":"https://doi.org/10.51380/GUJR-37-01-04","url":null,"abstract":"The climate variations have lot of the financial, medical and economic consequences. Studies showed that climate plays the vital role in virus transmission. This study analyzed the impact of climate indicators on COVID-19 concerning Pakistan. The secondary data is used for analysis as obtained from world health organization, ministry of health Pakistan and Pakistan meteorological department. The results show that all the research variables like temperature maximum, temperature minimum, humidity, and wind flow are positively and significantly correlated to COVID-19. Findings show that temperature maximum, temperature minimum, and wind flow have the positive and significant association with COVID-19, while the humidity has a positive impact on COVID-19 transmission. The study show that minimum temperature is favorable for the virus transmission. Thus, the study provides significant results in reaching the decision and concluding the study.","PeriodicalId":11002,"journal":{"name":"Day 1 Tue, March 23, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85428996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pakistan has been hosting Afghan refugees for almost four decades. These refugees are a burden on resources of country, hence Pakistan introduced repatriation of refugees with assistance of humanitarian organizations, but desired success not yet achieved. This study focused on "An analysis of economic factors influencing repatriation of the Afghan refugees from Pakistan”, therefore, utilized cross-sectional design to measure association between economic factors and expatriation. Study applied quantitative survey method to collect data through questionnaire. The simple random technique used to approach samples in population. Variables measured by the items selected from four different instruments. Data were analyzed with regression using SmartPLS. The results explored that productivity, labour market integration and access to shelter as indicators of economic factors for Afghan refugees in Pakistan are significantly associated with expatriation in presence of the mediating variable (economic well-being). Hence, a pull force of economic factors in Pakistan attracts them to stay in host country and avoid repatriation to homeland.
{"title":"AN ANALYSIS OF ECONOMIC FACTORS INFLUENCING REPATRIATION OF AFGHAN REFUGEES FROM PAKISTAN","authors":"U. Rehman, S. Abbas, Alamgeer Khan","doi":"10.51380/GUJR-37-01-02","DOIUrl":"https://doi.org/10.51380/GUJR-37-01-02","url":null,"abstract":"Pakistan has been hosting Afghan refugees for almost four decades. These refugees are a burden on resources of country, hence Pakistan introduced repatriation of refugees with assistance of humanitarian organizations, but desired success not yet achieved. This study focused on \"An analysis of economic factors influencing repatriation of the Afghan refugees from Pakistan”, therefore, utilized cross-sectional design to measure association between economic factors and expatriation. Study applied quantitative survey method to collect data through questionnaire. The simple random technique used to approach samples in population. Variables measured by the items selected from four different instruments. Data were analyzed with regression using SmartPLS. The results explored that productivity, labour market integration and access to shelter as indicators of economic factors for Afghan refugees in Pakistan are significantly associated with expatriation in presence of the mediating variable (economic well-being). Hence, a pull force of economic factors in Pakistan attracts them to stay in host country and avoid repatriation to homeland.","PeriodicalId":11002,"journal":{"name":"Day 1 Tue, March 23, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90490949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. M. M. Hashim, M. H. Yusoff, M. Arriffin, A. Mohamad, Tengku Ezharuddin Tengku Bidin, Dalila Gomes
The advancement of technology in this era has long profited the oil and gas industry by means of shrinking non-productive time (NPT) events and reducing drilling operational costs via real-time monitoring and intervention. Nevertheless, stuck pipe incidents have been a big concern and pain point for any drilling operations. Real-time monitoring with the aid of dynamic roadmaps of drilling parameters is useful in recognizing potential downhole issues but the initial stuck pipe symptoms are often minuscule in a short time frame hence it is a challenge to identify it in time. Wells Augmented Stuck Pipe Indicator (WASP) is a data-driven method leveraging historical drilling data and auxiliary engineering information to provide an impartial trend detection of impending stuck pipe incidents. WASP is a solution set to tackle the challenge. The solution is anchored on Machine Learning (ML) models which assess real-time drilling data and compute the risk of potential stuck pipe based on drilling activities, probable stuck pipe mechanisms, and operation time. The output of the analysis is built on a warning and alarm system that can be utilized by the engineers to refine and optimize the well construction activities; tackling the stuck pipe issue before it manifests. This solution is evaluated by comparing historical and real-time drilling parameters with the prediction data to generate an error analysis. On top of that, a confusion matrix is tabulated based on the analysis of warnings and alarms raised by the solution to rule out Type 1 and Type 2 errors. The WASP solution has demonstrated tolerably accurate predictions of drilling parameters with minimal warnings and alarms error. With the solution, the stuck pipe issue can be identified hours earlier before the actual stuck pipe was reported in the historical well. It is a powerful tool with the capability to pinpoint possible stuck pipe mechanisms for engineer's immediate analysis and intervention. Value creation from the WASP solution has been massive with a reduction in manhours of analysis, potential NPT events, and unexpected operational costs. Data-driven techniques are effective in preventing stuck pipe incidents and will be scalable to tackle other downhole issues such as loss of circulation, well control, and borehole instability.
{"title":"Performance Improvement of Wells Augmented Stuck Pipe Indicator via Model Evaluations","authors":"M. M. M. Hashim, M. H. Yusoff, M. Arriffin, A. Mohamad, Tengku Ezharuddin Tengku Bidin, Dalila Gomes","doi":"10.2523/IPTC-21455-MS","DOIUrl":"https://doi.org/10.2523/IPTC-21455-MS","url":null,"abstract":"\u0000 The advancement of technology in this era has long profited the oil and gas industry by means of shrinking non-productive time (NPT) events and reducing drilling operational costs via real-time monitoring and intervention. Nevertheless, stuck pipe incidents have been a big concern and pain point for any drilling operations. Real-time monitoring with the aid of dynamic roadmaps of drilling parameters is useful in recognizing potential downhole issues but the initial stuck pipe symptoms are often minuscule in a short time frame hence it is a challenge to identify it in time. Wells Augmented Stuck Pipe Indicator (WASP) is a data-driven method leveraging historical drilling data and auxiliary engineering information to provide an impartial trend detection of impending stuck pipe incidents. WASP is a solution set to tackle the challenge. The solution is anchored on Machine Learning (ML) models which assess real-time drilling data and compute the risk of potential stuck pipe based on drilling activities, probable stuck pipe mechanisms, and operation time. The output of the analysis is built on a warning and alarm system that can be utilized by the engineers to refine and optimize the well construction activities; tackling the stuck pipe issue before it manifests. This solution is evaluated by comparing historical and real-time drilling parameters with the prediction data to generate an error analysis. On top of that, a confusion matrix is tabulated based on the analysis of warnings and alarms raised by the solution to rule out Type 1 and Type 2 errors. The WASP solution has demonstrated tolerably accurate predictions of drilling parameters with minimal warnings and alarms error. With the solution, the stuck pipe issue can be identified hours earlier before the actual stuck pipe was reported in the historical well. It is a powerful tool with the capability to pinpoint possible stuck pipe mechanisms for engineer's immediate analysis and intervention. Value creation from the WASP solution has been massive with a reduction in manhours of analysis, potential NPT events, and unexpected operational costs. Data-driven techniques are effective in preventing stuck pipe incidents and will be scalable to tackle other downhole issues such as loss of circulation, well control, and borehole instability.","PeriodicalId":11002,"journal":{"name":"Day 1 Tue, March 23, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88610075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A 3D surface seismic data acquisition project was conducted simultaneously with 3D DAS-VSP data acquisition in one well in Jilin Oilfield of Northen China. The 3D surface seismic data acquisition project covered an area of 75 km2, and one borehole (DS32-3) and an armoured optical cable with high temperature single mode fiber were used to acquire the 3D DAS-VSP data simultaneously when the crew was acquiring the 3D surface seismic data. The simultaneously acquired 3D DAS-VSP data were used to extract formation velocity, deconvolution operator, absorption, attenuation (Q value), anisotropy parameters (η, δ, ε) as wel as enhanced the surface seismic data processing including velocity model calibration and modification, static correction, deconvolution, demultiple processing, high frequency restoration, anisotropic migration, and Q-compensation or Q-migration. In this project, anisotropic migration, Q-migration was conducted with the anisotropy parameters (η, δ, ε) data volume and enhanced Q-field data volume obtained from the joint inversion of both the near surface 3D Q-field data volume from uphole data and the mid-deep layer Q-field data volume from all available VSP data in the 3D surface seismic surveey area. The anosotropic migration and Q-migration results show much sharper and focussed faults and and clearer subsutface structure.
{"title":"Borehole-Driven 3D Surface Seismic Data Processing Using DAS-VSP Data","authors":"Gang Yu, W. Junjun, Yuanzhong Chen, Ximing Wang","doi":"10.2523/IPTC-21463-MS","DOIUrl":"https://doi.org/10.2523/IPTC-21463-MS","url":null,"abstract":"\u0000 A 3D surface seismic data acquisition project was conducted simultaneously with 3D DAS-VSP data acquisition in one well in Jilin Oilfield of Northen China. The 3D surface seismic data acquisition project covered an area of 75 km2, and one borehole (DS32-3) and an armoured optical cable with high temperature single mode fiber were used to acquire the 3D DAS-VSP data simultaneously when the crew was acquiring the 3D surface seismic data.\u0000 The simultaneously acquired 3D DAS-VSP data were used to extract formation velocity, deconvolution operator, absorption, attenuation (Q value), anisotropy parameters (η, δ, ε) as wel as enhanced the surface seismic data processing including velocity model calibration and modification, static correction, deconvolution, demultiple processing, high frequency restoration, anisotropic migration, and Q-compensation or Q-migration. In this project, anisotropic migration, Q-migration was conducted with the anisotropy parameters (η, δ, ε) data volume and enhanced Q-field data volume obtained from the joint inversion of both the near surface 3D Q-field data volume from uphole data and the mid-deep layer Q-field data volume from all available VSP data in the 3D surface seismic surveey area. The anosotropic migration and Q-migration results show much sharper and focussed faults and and clearer subsutface structure.","PeriodicalId":11002,"journal":{"name":"Day 1 Tue, March 23, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85740406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yeek Huey Ho, Ryan Guillory, A. Sinha, Rusli Din, R. Ranjan, R. Masoudi
As host authority for all hydrocarbon resources in Malaysia, Petroliam Nasional Berhad (PETRONAS) Malaysia Petroleum Management (MPM) has championed Asset Value Framing (AVF) since 2016 to facilitate identification of asset enhancing opportunities and to establish a roadmap for opportunity realization. This paper is the continuation of the previous paper (SPE-196486) which illustrated opportunity identification through AVF. In 2019, PETRONAS had embarked on benchmarking oil reservoirs for all Malaysian oil reservoirs which was used for the AVF process to improve economic recovery factor of an oil field and booking new contingent resources. This paper focuses on enhanced AVF approach to integrate subsurface, wells, surface and operations; coupled with recommended improvements to AVF process from lookback exercise, reservoir performance assessment, data analytic through reservoir benchmarking tool and assessment of analogue reservoirs. A case study will be shared from one of the largest oilfields in Sarawak wherein enhanced AVF approach was applied to unlock significant potential of which conventional techniques faced challenges in identifying opportunities. Field B consists of multi-layered depositional system with numerous fault-bounded accumulation areas. Benchmarking process was performed for each of reservoir units to estimate the potential recovery factor and degree of complexity. In reservoirs where current estimates of recovery factor were lower than the benchmark, these were screened to be considered for identification of new opportunities through AVF process. Additionally, benchmarking process was applied to evaluate optimal well spacing, need for secondary recovery and identification of potential challenges for future development planning. A paradigm shift was undertaken to AVF process itself whereby focused development plan was considered for the entire column of rock within every fault block - instead of chasing oil by reservoirs. This subsequently allowed an integrated approach to optimize well type and cost, infill and water injection well count, completion design and overall evacuation strategy. Application of reservoir benchmarking significantly improved the delivery of AVF process by identification of recovery gaps in the field and application of learnings from better performing reservoirs. This coupled with Enhanced AVF workflow approach of focused development plan has resulted a roadmap for Field B to achieve ultimate recovery factor of 40% through a number of potential development opportunities within the next few years. An enhanced AVF workflow coupled with benchmarking process has facilitated field potential evaluation within two months, leading to efficient decision making, resource accrual and value creation for all stakeholders. This workflow can be replicated to other fields, maximizing economic reserves, increasing asset value, and defining the development roadmap.
{"title":"Application of Enhanced Asset Value Framing AVF Approach to Unlock Significant Potential Value in Highly Compartmentalised and Stacked Reservoirs","authors":"Yeek Huey Ho, Ryan Guillory, A. Sinha, Rusli Din, R. Ranjan, R. Masoudi","doi":"10.2523/IPTC-21831-MS","DOIUrl":"https://doi.org/10.2523/IPTC-21831-MS","url":null,"abstract":"\u0000 As host authority for all hydrocarbon resources in Malaysia, Petroliam Nasional Berhad (PETRONAS) Malaysia Petroleum Management (MPM) has championed Asset Value Framing (AVF) since 2016 to facilitate identification of asset enhancing opportunities and to establish a roadmap for opportunity realization. This paper is the continuation of the previous paper (SPE-196486) which illustrated opportunity identification through AVF. In 2019, PETRONAS had embarked on benchmarking oil reservoirs for all Malaysian oil reservoirs which was used for the AVF process to improve economic recovery factor of an oil field and booking new contingent resources. This paper focuses on enhanced AVF approach to integrate subsurface, wells, surface and operations; coupled with recommended improvements to AVF process from lookback exercise, reservoir performance assessment, data analytic through reservoir benchmarking tool and assessment of analogue reservoirs. A case study will be shared from one of the largest oilfields in Sarawak wherein enhanced AVF approach was applied to unlock significant potential of which conventional techniques faced challenges in identifying opportunities.\u0000 Field B consists of multi-layered depositional system with numerous fault-bounded accumulation areas. Benchmarking process was performed for each of reservoir units to estimate the potential recovery factor and degree of complexity. In reservoirs where current estimates of recovery factor were lower than the benchmark, these were screened to be considered for identification of new opportunities through AVF process. Additionally, benchmarking process was applied to evaluate optimal well spacing, need for secondary recovery and identification of potential challenges for future development planning. A paradigm shift was undertaken to AVF process itself whereby focused development plan was considered for the entire column of rock within every fault block - instead of chasing oil by reservoirs. This subsequently allowed an integrated approach to optimize well type and cost, infill and water injection well count, completion design and overall evacuation strategy.\u0000 Application of reservoir benchmarking significantly improved the delivery of AVF process by identification of recovery gaps in the field and application of learnings from better performing reservoirs. This coupled with Enhanced AVF workflow approach of focused development plan has resulted a roadmap for Field B to achieve ultimate recovery factor of 40% through a number of potential development opportunities within the next few years.\u0000 An enhanced AVF workflow coupled with benchmarking process has facilitated field potential evaluation within two months, leading to efficient decision making, resource accrual and value creation for all stakeholders. This workflow can be replicated to other fields, maximizing economic reserves, increasing asset value, and defining the development roadmap.","PeriodicalId":11002,"journal":{"name":"Day 1 Tue, March 23, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83571900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. I. Azahree, F. Azuddin, S. S. Ali, M. H. Yakup, M. A. Mustafa, A. Widyanita, R. Kalita
A depleted gas field is selected as CO2 storage site for future high CO2 content gas field development in Malaysia. The reservoir selected is a carbonate buildup of middle to late Miocene age. This paper describes an integrated modeling approach to evaluate CO2 sequestration potential in depleted carbonate gas reservoir. Integrated dynamic-geochemical and dynamic-geomechanics coupled modeling is required to properly address the risks and uncertainties such as, effect of compaction and subsidence during post-production and injection. The main subsurface uncertainties for assessing the CO2 storage potential are (i) CO2 storage capacity due to higher abandonment pressure (ii) CO2 containment due to geomechanical risks (iii) change in reservoir properties due to reaction of reservoir rock with injected CO2. These uncertainties have been addressed by first building the compositional dynamic model adequately history matched to the production data, and then coupling with geomechanical model and geochemical module during the CO2 injection phase. This is to further study on the trapping mechanisms, caprock integrity, compaction-subsidence implication towards maximum storage capacity and injectivity. The initial standalone dynamic modeling poses few challenges to match the water production in the field due to presence of karsts, extent of a baffle zone between the aquifer and producing zones and uncertainty in the aquifer volume. The overall depletion should be matched, since the field abandonment pressure impacts the CO2 injectivity and storage capacity. A reasonably history matched coupled dynamic-geomechanical model is used as base case for simulating CO2 injection. The dynamic-geomechanical coupling is done with 8 stress steps based on critical pressure changes throughout production and CO2 injection phase. Overburden and reservoir properties has been mapped in Geomechanical grid and was run using two difference constitutive model; Mohr's Coulomb and Modified Cam Clay respectively. The results are then calibrated with real subsidence measurement at platform location. This coupled model has been used to predict the maximum CO2 injection rate of 100 MMscf/d/well and a storage capacity of 1.34 Tscf. The model allows to best design the injection program in terms of well location, target injection zone and surface facilities design. This coupled modeling study is used to mature the field as a viable storage site. The established workflow starting from static model to coupled model to forecasting can be replicated in other similar projects to ensure the subsurface robustness, reduce uncertainty and risk mitigation of the field for CO2 storage site.
{"title":"Integrated Coupled Modelling Study to Assess CO2 Sequestration Potential in a Depleted Gas Field","authors":"A. I. Azahree, F. Azuddin, S. S. Ali, M. H. Yakup, M. A. Mustafa, A. Widyanita, R. Kalita","doi":"10.2523/IPTC-21859-MS","DOIUrl":"https://doi.org/10.2523/IPTC-21859-MS","url":null,"abstract":"\u0000 A depleted gas field is selected as CO2 storage site for future high CO2 content gas field development in Malaysia. The reservoir selected is a carbonate buildup of middle to late Miocene age. This paper describes an integrated modeling approach to evaluate CO2 sequestration potential in depleted carbonate gas reservoir. Integrated dynamic-geochemical and dynamic-geomechanics coupled modeling is required to properly address the risks and uncertainties such as, effect of compaction and subsidence during post-production and injection. The main subsurface uncertainties for assessing the CO2 storage potential are (i) CO2 storage capacity due to higher abandonment pressure (ii) CO2 containment due to geomechanical risks (iii) change in reservoir properties due to reaction of reservoir rock with injected CO2. These uncertainties have been addressed by first building the compositional dynamic model adequately history matched to the production data, and then coupling with geomechanical model and geochemical module during the CO2 injection phase. This is to further study on the trapping mechanisms, caprock integrity, compaction-subsidence implication towards maximum storage capacity and injectivity. The initial standalone dynamic modeling poses few challenges to match the water production in the field due to presence of karsts, extent of a baffle zone between the aquifer and producing zones and uncertainty in the aquifer volume. The overall depletion should be matched, since the field abandonment pressure impacts the CO2 injectivity and storage capacity. A reasonably history matched coupled dynamic-geomechanical model is used as base case for simulating CO2 injection. The dynamic-geomechanical coupling is done with 8 stress steps based on critical pressure changes throughout production and CO2 injection phase. Overburden and reservoir properties has been mapped in Geomechanical grid and was run using two difference constitutive model; Mohr's Coulomb and Modified Cam Clay respectively. The results are then calibrated with real subsidence measurement at platform location. This coupled model has been used to predict the maximum CO2 injection rate of 100 MMscf/d/well and a storage capacity of 1.34 Tscf. The model allows to best design the injection program in terms of well location, target injection zone and surface facilities design. This coupled modeling study is used to mature the field as a viable storage site. The established workflow starting from static model to coupled model to forecasting can be replicated in other similar projects to ensure the subsurface robustness, reduce uncertainty and risk mitigation of the field for CO2 storage site.","PeriodicalId":11002,"journal":{"name":"Day 1 Tue, March 23, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85602279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-05DOI: 10.21475/AJCS.21.15.03.P2812
M. Rehman, Z. Singh, T. Khurshid, R. Malekipoor, V. Y. Tokala
Poor rind colour in cv. M7 Navel (Citrus sinensis L. Osbeck) at harvest time severely affects the profits of the growers in Western Australia. The effects of the preharvest spray application of different concentrations (0, 1.25, 2.5, 5.0 and 7.5 mM) of methyl jasmonate (MJ) on the rind colour development and fruit quality of M7 Navel were investigated at 6 or 3 weeks before anticipated harvest (WBAH) during 2015 and 2016. The preharvest spray application of MJ (5.0 or 7.5 mM) resulted in enhanced rind colour, reduced hue angle (ho) angle (55.7, 54.3) as well as increased citrus colour index (CCI) (11.0, 12.0) and total carotenoid levels (35.3, 58.3 mg kg-1) of flavedo, respectively in M7 Navel, during 2015 and 2016. During 2015, comparatively higher levels of total carotenoid (40.4 mg kg-1) were recorded when MJ was applied at 3 WBAH as a single spray. However, the time of MJ application did not influence hue angle (h°) and CCI. In 2015, all the preharvest MJ treatments except (1.25 mM) exhibited reduced fruit firmness. Furthermore, soluble solids concentration (SSC) in the fruit juice was reduced after MJ treatment. All the MJ treatments showed reduced levels of total sugars and organic acids in the juice, during 2015. In conclusion, MJ (5.0 or 7.5 mM) reduced h° but increased the total carotenoids levels and CCI in the flavedo of M7 Navel orange, when applied as a preharvest spray at 3 WBAH
{"title":"Preharvest spray application of methyl jasmonate promotes fruit colour and regulates quality in M7 Navel orange grown in a Mediterranean climate","authors":"M. Rehman, Z. Singh, T. Khurshid, R. Malekipoor, V. Y. Tokala","doi":"10.21475/AJCS.21.15.03.P2812","DOIUrl":"https://doi.org/10.21475/AJCS.21.15.03.P2812","url":null,"abstract":"Poor rind colour in cv. M7 Navel (Citrus sinensis L. Osbeck) at harvest time severely affects the profits of the growers in Western Australia. The effects of the preharvest spray application of different concentrations (0, 1.25, 2.5, 5.0 and 7.5 mM) of methyl jasmonate (MJ) on the rind colour development and fruit quality of M7 Navel were investigated at 6 or 3 weeks before anticipated harvest (WBAH) during 2015 and 2016. The preharvest spray application of MJ (5.0 or 7.5 mM) resulted in enhanced rind colour, reduced hue angle (ho) angle (55.7, 54.3) as well as increased citrus colour index (CCI) (11.0, 12.0) and total carotenoid levels (35.3, 58.3 mg kg-1) of flavedo, respectively in M7 Navel, during 2015 and 2016. During 2015, comparatively higher levels of total carotenoid (40.4 mg kg-1) were recorded when MJ was applied at 3 WBAH as a single spray. However, the time of MJ application did not influence hue angle (h°) and CCI. In 2015, all the preharvest MJ treatments except (1.25 mM) exhibited reduced fruit firmness. Furthermore, soluble solids concentration (SSC) in the fruit juice was reduced after MJ treatment. All the MJ treatments showed reduced levels of total sugars and organic acids in the juice, during 2015. In conclusion, MJ (5.0 or 7.5 mM) reduced h° but increased the total carotenoids levels and CCI in the flavedo of M7 Navel orange, when applied as a preharvest spray at 3 WBAH","PeriodicalId":11002,"journal":{"name":"Day 1 Tue, March 23, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80879578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-01DOI: 10.36263/nijest.2021.01.0263
P. Opute, I. Oboh
Clarias gariepinus juveniles of average weight, 17.57±1.95 g and an average length of 14.26±0.39 cm were exposed to environmentally relevant concentrations of 0 (control), 2.5, 25, 250, and 500 µg L-1 atrazine in a quality-controlled 28-day bioassay. Growth performance was assessed bi-weekly and fish samples were taken from different tanks to determine the relative growth rate, specific growth rate, feed conversion ratio, condition factor and behaviour. At the end of two weeks of exposure, the relative growth rate and the specific growth rate among exposed fish groups was found to reduce significantly (p<0.05) compared to the control, an indication of poor growth performance. The average specific growth rates (SGR) of control fish is 3.86±0.02 %/w at the end of the exposure duration while recording -0.64±0.09 in the 500 µg L-1 group. Feed conversion ratio increased significantly from control to the group with highest atrazine concentration. Condition factor (K) of fish among treatment groups showed significant decrease in values with increasing concentration of atrazine in a dose-dependent pattern. Atrazine exposure resulted in behavioural anomalies including erratic swimming, clinging to the water surface, loss of equilibrium, lethargy, and discolouration. The behavioural responses were found to be concentration-dependent. The length-weight relationships for both control and atrazine exposed fish exhibited positive allometric growth and significant relationships as depicted by the value of R2 (coefficient of determination) except in the fish group exposed to 500 µg L-1 atrazine which exhibited negative allometric growth. Findings from this study indicate interference with normal behaviour and growth performance of C. gariepinus juveniles with ecological implications in water bodies exposed to atrazine even at reduced concentrations.
将平均体重为17.57±1.95 g、平均体长为14.26±0.39 cm的Clarias gariepinus幼鱼暴露于环境相关浓度为0(对照)、2.5、25、250和500µg L-1的阿特拉津中进行28天的质量控制生物测定。每两周对生长性能进行评估，并从不同的鱼缸中取鱼样，以确定相对生长率、特定生长率、饲料系数、条件因子和行为。暴露2周后，与对照组相比，暴露组的相对生长率和特定生长率显著降低(p<0.05)，显示出较差的生长性能。对照鱼的平均特定生长率(SGR)在暴露时间结束时为3.86±0.02 %/w，而500µg L-1组为-0.64±0.09。从对照组到阿特拉津浓度最高组，饲料系数显著提高。各处理组鱼的条件因子(K)随阿特拉津浓度的增加呈剂量依赖性显著降低。接触阿特拉津会导致行为异常，包括不稳定的游泳、粘在水面上、失去平衡、嗜睡和变色。行为反应被发现是浓度依赖的。除了暴露于500 μ g L-1阿特拉津的鱼组表现出负异速生长外，对照组和暴露于阿特拉津的鱼的长度-重量关系均表现出正异速生长，并通过R2(决定系数)的值描述了显著的关系。本研究的结果表明，即使在低浓度的阿特拉津环境中，也会干扰加里滨鲟幼体的正常行为和生长性能，具有生态意义。
{"title":"Exposure to Atrazine Impairs Behaviour and Growth Performance in African Catfish, Clarias gariepinus (Burchell, 1822) Juveniles","authors":"P. Opute, I. Oboh","doi":"10.36263/nijest.2021.01.0263","DOIUrl":"https://doi.org/10.36263/nijest.2021.01.0263","url":null,"abstract":"Clarias gariepinus juveniles of average weight, 17.57±1.95 g and an average length of 14.26±0.39 cm were exposed to environmentally relevant concentrations of 0 (control), 2.5, 25, 250, and 500 µg L-1 atrazine in a quality-controlled 28-day bioassay. Growth performance was assessed bi-weekly and fish samples were taken from different tanks to determine the relative growth rate, specific growth rate, feed conversion ratio, condition factor and behaviour. At the end of two weeks of exposure, the relative growth rate and the specific growth rate among exposed fish groups was found to reduce significantly (p<0.05) compared to the control, an indication of poor growth performance. The average specific growth rates (SGR) of control fish is 3.86±0.02 %/w at the end of the exposure duration while recording -0.64±0.09 in the 500 µg L-1 group. Feed conversion ratio increased significantly from control to the group with highest atrazine concentration. Condition factor (K) of fish among treatment groups showed significant decrease in values with increasing concentration of atrazine in a dose-dependent pattern. Atrazine exposure resulted in behavioural anomalies including erratic swimming, clinging to the water surface, loss of equilibrium, lethargy, and discolouration. The behavioural responses were found to be concentration-dependent. The length-weight relationships for both control and atrazine exposed fish exhibited positive allometric growth and significant relationships as depicted by the value of R2 (coefficient of determination) except in the fish group exposed to 500 µg L-1 atrazine which exhibited negative allometric growth. Findings from this study indicate interference with normal behaviour and growth performance of C. gariepinus juveniles with ecological implications in water bodies exposed to atrazine even at reduced concentrations.","PeriodicalId":11002,"journal":{"name":"Day 1 Tue, March 23, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84781758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-03-01DOI: 10.36263/NIJEST.2021.01.0253
S. Ogunlade
he protection of ecosystem and preservation of biodiversity through the approach of geospatial technology was the aim of this research. The channel was monitoring the spatial transformation of the Federal University of Technology, Akure, Nigeria between year 2002 and year 2018 using Satellite Remote Sensing and Geographical Information System techniques. Landsat 7 Enhanced Thematic Mapper (ETM) plus of year 2002, Landsat 8 Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) of year 2014 and year 2018 all of 32m resolution were the satellite images obtained for the study. These images were processed with supervised maximum likelihood classification algorithm using ArcGIS 10.3 software. To validate the classification and ensure high accuracy, an accuracy assessment was performed using training samples from 60 points on each of the satellite imagery on a reference image from google earth combined with ground data collected on actual visitation to the study area to verify the true land-cover type existing on the site. The resultant images deemed fit for analyses were classified into built-up, thick vegetation, light vegetation and bare land, land cover classes. Microsoft Excel spreadsheet was used to perform land cover area calculations through which the land cover dynamics and the spatial expansion were identified. The result showed built-up (13.58%, 14.59%, 20.75%); thick vegetation (33.78%, 26.26%, 12.18%); Light vegetation (24.57%, 32.29%, 30.51%); Bare land (28.08%, 26.26%, 36.56%) for the three years respectively. A special focus was put on the general depletion of the (thick and light) vegetation of which trees are a major actor. These depletion were adduced to the positive transformation of other land cover classes through the underlining landuse. The study concluded that alteration, depletion and consequent disappearance of trees in the green ecosystem is a threat to environment’s sustainability and the protection of ecosystem and preservation of biodiversity. The study recommended the research as a tool to controlling the removal of trees and thick forest, growing more trees and plants among other factors to protect ecosystem and preserve biodiversity.
{"title":"Protection of Ecosystem and Preservation of Biodiversity: The Geospatial Technology Approach","authors":"S. Ogunlade","doi":"10.36263/NIJEST.2021.01.0253","DOIUrl":"https://doi.org/10.36263/NIJEST.2021.01.0253","url":null,"abstract":"he protection of ecosystem and preservation of biodiversity through the approach of geospatial technology was the aim of this research. The channel was monitoring the spatial transformation of the Federal University of Technology, Akure, Nigeria between year 2002 and year 2018 using Satellite Remote Sensing and Geographical Information System techniques. Landsat 7 Enhanced Thematic Mapper (ETM) plus of year 2002, Landsat 8 Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) of year 2014 and year 2018 all of 32m resolution were the satellite images obtained for the study. These images were processed with supervised maximum likelihood classification algorithm using ArcGIS 10.3 software. To validate the classification and ensure high accuracy, an accuracy assessment was performed using training samples from 60 points on each of the satellite imagery on a reference image from google earth combined with ground data collected on actual visitation to the study area to verify the true land-cover type existing on the site. The resultant images deemed fit for analyses were classified into built-up, thick vegetation, light vegetation and bare land, land cover classes. Microsoft Excel spreadsheet was used to perform land cover area calculations through which the land cover dynamics and the spatial expansion were identified. The result showed built-up (13.58%, 14.59%, 20.75%); thick vegetation (33.78%, 26.26%, 12.18%); Light vegetation (24.57%, 32.29%, 30.51%); Bare land (28.08%, 26.26%, 36.56%) for the three years respectively. A special focus was put on the general depletion of the (thick and light) vegetation of which trees are a major actor. These depletion were adduced to the positive transformation of other land cover classes through the underlining landuse. The study concluded that alteration, depletion and consequent disappearance of trees in the green ecosystem is a threat to environment’s sustainability and the protection of ecosystem and preservation of biodiversity. The study recommended the research as a tool to controlling the removal of trees and thick forest, growing more trees and plants among other factors to protect ecosystem and preserve biodiversity.","PeriodicalId":11002,"journal":{"name":"Day 1 Tue, March 23, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87884060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-01DOI: 10.36263/nijest.2021.01.0269
F. Ogbeide, J. Ehiorobo, O. Izinyon, I. Ilaboya
Time overrun of completed road projects awarded by the Niger Delta Development Commission (NDDC) in the Niger Delta Region of Nigeria from its inception in 2000 up to 2015 was studied. Out of 3315 roads awarded, only 1081 roads representing 31.65 percent were completed within the review period. The qualitative study was carried out on randomly selected completed 162 road projects for analysis, and a conceptual model of time series was developed. In developing the regression model, both dependent and independent variables were subjected to normality tests assessed by skewness coefficient, kurtosis value, Jarque-Bera test, residual probability plot, heteroscedasticity test and the variance inflation factor. Also, with knowledge of total road projects awarded by the Commission, it is now possible to predict proportions of roads experiencing schedule overruns.
{"title":"A Qualitative Study of Time Overrun of Completed Road Projects Awarded by the Niger Delta Development Commission in the Niger Delta Region of Nigeria","authors":"F. Ogbeide, J. Ehiorobo, O. Izinyon, I. Ilaboya","doi":"10.36263/nijest.2021.01.0269","DOIUrl":"https://doi.org/10.36263/nijest.2021.01.0269","url":null,"abstract":"Time overrun of completed road projects awarded by the Niger Delta Development Commission (NDDC) in the Niger Delta Region of Nigeria from its inception in 2000 up to 2015 was studied. Out of 3315 roads awarded, only 1081 roads representing 31.65 percent were completed within the review period. The qualitative study was carried out on randomly selected completed 162 road projects for analysis, and a conceptual model of time series was developed. In developing the regression model, both dependent and independent variables were subjected to normality tests assessed by skewness coefficient, kurtosis value, Jarque-Bera test, residual probability plot, heteroscedasticity test and the variance inflation factor. Also, with knowledge of total road projects awarded by the Commission, it is now possible to predict proportions of roads experiencing schedule overruns.","PeriodicalId":11002,"journal":{"name":"Day 1 Tue, March 23, 2021","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85346962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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