Material with unique metallurgical properties such as Titanium, Haynes-25, Molybdenum, Columbium C-103, hardened steels, and other superalloys was developed to meet the demands of extreme applications in aerospace, automobile, and nuclear... more
Material with unique metallurgical properties such as Titanium, Haynes-25, Molybdenum, Columbium C-103, hardened steels, and other superalloys was developed to meet the demands of extreme applications in aerospace, automobile, and nuclear reactor industries. Machining these materials using a conventional machining process is a challenging task. Electrical discharge machining (EDM) is one of the most suitable non-conventional processes to achieve precise quality components with optimum tooling cost. EDM process becomes a natural choice for machining of superalloys; its low machining removal rate and poor surface quality have been the key problems restricting its development. To overcome these drawbacks, the nanopowder suspended dielectric oil is used, which increases its conductive strength and increases the discharge gap between the tool and workpiece. This newly developed material removal process is called Powder Mixed Electrical Discharge Machining (PMEDM). This paper presents the review work done to improve the performance characteristics of machining like MRR, TWR, EWR, SR, Microhardness, and SCD for different Machining parameters. This paper also reviewed the industrial and academic work performed by various researchers from the origin to the development of PMEDM over the past decades. The research findings with major challenges along with the future scope have also been paved out.
Reports are available that most rural communities in Akwa Ibom State have limited access to safe drinking water, and the few drinking water sources they have are usually heavily polluted. The aim of this study was to assess access to safe... more
Reports are available that most rural communities in Akwa Ibom State have limited access to safe drinking water, and the few drinking water sources they have are usually heavily polluted. The aim of this study was to assess access to safe drinking water and the water quality of rural upland and coastal communities of Akwa Ibom State. With a cross-sectional design, 420 respondents were selected and administered questionnaires to obtain information on water sources and water supply facilities, followed by physicochemical and bacteriological analyses of the water sources of the communities using standard procedures. Two-way analysis of variance (ANOVA) was used to determine differences in means of the water qualities between coastal and upland water sources and between rainy and dry seasons. The statistical analysis was done using SPSS version 20. Result shows that respondents in upland (83.33%) and coastal (58.10%) communities obtained water from improved water sources, 16.67% and 41.90% respectively obtained from unimproved sources. The physical parameters were either below or within the accepted standards in both dry and rainy seasons in the communities. There was no significant difference (P>0.05) between upland and coastal water samples. The general pattern of metal concentration in dry season followed the sequence: Hg<Pb<Cd<As<Mn<Fe<Cr, while in the rainy season, it was Hg<Cd<Pb<As<Mn<Fe<Cr. This indicates that in both dry and rainy seasons the concentration of mercury is the least, and chromium is the highest. In the dry and rainy seasons, viable bacterial count, and total coliform were high. In particular, faecal coliform count ranged from 1.02 ± 0.14 ×10 2 cfu/100ml in the dry season to 0.41 ± 0.10 ×10 2 cfu/100ml in the rainy season, all above the recommended standards. It is concluded that access to water sources and the quality of the water are not adequate and calls for water treatment in the home.
The present investigation on MIG welding machine performed on bright Mild Steel is conducted to establish the influence of welding current, welding voltage and weld speed on hardness and surface quality. The... more
The present investigation on MIG welding machine performed on bright Mild Steel is conducted to establish the influence of welding current, welding voltage and weld speed on hardness and surface quality. The experimental results concluded that hardness is mainly influenced by welding voltage followed by welding current and least by welding speed. In the case of surface quality assessed by SEM, it was found that each parameter has great influence on the quality of surface produced.
The study evaluated the physic-chemical and heavy metal content of River Olosun in Ibadan Metropolis, Oyo State. Surface water samples were collected upstream and downstream of River Olosun and analyzed using standard methods. Result of... more
The study evaluated the physic-chemical and heavy metal content of River Olosun in Ibadan Metropolis, Oyo State. Surface water samples were collected upstream and downstream of River Olosun and analyzed using standard methods. Result of principal components analysis (PCA) extracted two latent (2) components at both upstream and downstream responsible for the pollution of the river. The latent components explained 95 – 98% of the total variance in the water parameter data set. PCA result revealed that chromium (Cr) and iron (Fe) were the most impacted water properties upstream, while iron (Fe) and zinc (Zn) were mostly affected by the numerous human activities within and around the river’s catchment. The study indicated that River Olosun had High level of chemical and organic pollution.
As a developing country, industrialization is rapidly growing up in Bangladesh. Most of the cases, the industrialization process don’t considering any impact on environmental body. In this study, the impact of unplanned industrialization... more
As a developing country, industrialization is rapidly growing up in Bangladesh. Most of the cases, the industrialization process don’t considering any impact on environmental body. In this study, the impact of unplanned industrialization on the surface water is the main focus. In between several resources, the water quality of the Sitalakhya River is our study area. Quality of the Sitalakhya River water is getting polluted day by day through industrial effluents and household wastewater, lube oil and oil spillage around the operation of river ports. The Sitalakhya river water quality analysis is considered between 1975 to 2018, qualitative and quantitative results for pH, DO and BOD were analyzed and also trends of these parameters were also analyzed. Day by day river water quality going far away from EQS value, which is significantly harmful to flora fauna. In this circumstance, industrial effluent and other environmental impacts from unplanned industrialization is main goal of thi...
Laboratory experiments were carried out to investigate electrocoagulation (EC) of Ghrib Dam’s water (Algeria) in batch using aluminium and iron electrodes without addition of chemicals, without pH modifi cation, and without agitation. The... more
Laboratory experiments were carried out to investigate electrocoagulation (EC) of Ghrib Dam’s water (Algeria) in batch using aluminium and iron electrodes without addition of chemicals, without pH modifi cation, and without agitation. The optimal conditions are an applied voltage of direct current of 8 V and a current density 74 A m−2 (0.35 A ) during 45 min for both electrodes. The microbial pollution is completely removed by essentially electrical field whereas conductivity and turbidity are reduced at 27 and 85% respectively for Fe electrodes and 22 and 97% for Al electrodes by metallic cations. These results prove that water treatment by EC using Al electrodes (flotation) for low turbid water (7 NTU) is more convenient than Fe electrodes (sedimentation) for both turbidity and organic matter removal. A new parameter to be taken in consideration for EC reactor design the ratio r active volume on reactor volume which is full of water is introduced where the active volume is the active surface multiplied by the distance between the electrodes.
Variation in water temperature has been identified as a trigger for initiation of spawning for several species of fish. In this paper, the development and verification of a model for predicting temporal patterns of spawning based on... more
Variation in water temperature has been identified as a trigger for initiation of spawning for several species of fish. In this paper, the development and verification of a model for predicting temporal patterns of spawning based on temperature variation is presented. The model is based on assuming a normally distributed temperature trigger for initiation of spawning over the spawning fish population. The model has been applied to observed egg concentrations, a proxy for spawning activity, of two species of anadromous fish: striped bass (Morone saxitalis) and American shad (Alosa sapidissima) in the San Francisco Bay and Delta. The model was able to successfully reproduce the observed temporal patterns of spawning. Parameter estimation was performed based on four years of data by employing a Bayesian approach. Time-series water temperature data and observed egg concentrations in historic datasets was used to estimate the model parameters for each fish species, and it was found that the model is capable of capturing the observed egg concentrations (i.e., spawning trends) in all years of the historic dataset using the same set of parameters. The mean optimum spawning temperature was 18.0⁰C for striped bass, and 20.8⁰C for American Shad, which is consistent with biological studies. Application of the model to predict the effects of climate change suggests that future conditions will result in an increase in the duration of the spawning season both species, as well progressively earlier dates of peak spawning.
The potential effect of canopy cover on the quality of River Offin which serves as drinking water for communities including Hwediem, Mprim and Boanim in the Mampong Municipality of the Ashanti region of Ghana was studied. These... more
The potential effect of canopy cover on the quality of River Offin which serves as drinking water for communities including Hwediem, Mprim and Boanim in the Mampong Municipality of the Ashanti region of Ghana was studied. These communities exemplify Ghanaian farming communities. Often, rural farmers do not have access to clean water. Using the part of the river serving these communities as a test case, we assessed the quality of water along a gradient of three different levels of canopy cover (closed, semi-closed and open canopy) where residents frequently access water. Physico-chemical tests showed that, the level of most of the physical and chemical properties of the water under all three different canopy covers was within the acceptable limits set by the World Health Organization. There was low turbidity where the canopy was closed resulting in relatively lower faecal coliforms. Total dissolved solids were also less where canopy cover was closed. Therefore, the general water quality could be potentially improved by planting trees along the river to form canopy.
Stormwater runoff management is challenging in a highly urbanised tropical environment due to the unique space constraints and tropical climate conditions. A modular bioretention tree (MBT) with a small footprint and a reduced on-site... more
Stormwater runoff management is challenging in a highly urbanised tropical environment due to the unique space constraints and tropical climate conditions. A modular bioretention tree (MBT) with a small footprint and a reduced on-site installation time was explored for application in a tropical environment. Tree species used in the pilot studies were Talipariti tiliaceum (TT1) and Sterculia macrophylla (TT2). Both of the MBTs could effectively remove total suspended solids (TSS), total phosphorus (TP), zinc, copper, cadmium, and lead with removal efficiencies of greater than 90%. Total nitrogen (TN) removal was noted to be significantly higher in the wet period compared to the dry period (p < 0.05). Variation in TN removal between TT1 and TT2 were attributed to the nitrogen uptake and the root formation of the trees species. A field study MBT using Talipariti tiliaceum had a very clean effluent quality, with average TSS, TP, and TN effluent EMC of 4.8 mg/L, 0.04 mg/L, and 0.27 mg...
As a developing country, industrialization is rapidly growing up in Bangladesh. Most of the cases, the industrialization process don't considering any impact on environmental body. In this study, the impact of unplanned industrialization... more
As a developing country, industrialization is rapidly growing up in Bangladesh. Most of the cases, the industrialization process don't considering any impact on environmental body. In this study, the impact of unplanned industrialization on the surface water is the main focus. In between several resources, the water quality of the Sitalakhya River is our study area. Quality of the Sitalakhya River water is getting polluted day by day through industrial effluents and household wastewater, lube oil and oil spillage around the operation of river ports. The Sitalakhya river water quality analysis is considered between 1975 to 2018, qualitative and quantitative results for pH, DO and BOD were analyzed and also trends of these parameters were also analyzed. Day by day river water quality going far away from EQS value, which is significantly harmful to flora fauna. In this circumstance, industrial effluent and other environmental impacts from unplanned industrialization is main goal of this study. This study shows, how unplanned industrialization can damage an environmental system which is very harmful to our entire ecological cycle. If cannot control this unplanned industrialization, water body will damage and all related ecosystem will be effected.
Stormwater runoff management is challenging in a highly urbanised tropical environment due to the unique space constraints and tropical climate conditions. A modular bioretention tree (MBT) with a small footprint and a reduced on-site... more
Stormwater runoff management is challenging in a highly urbanised tropical environment due to the unique space constraints and tropical climate conditions. A modular bioretention tree (MBT) with a small footprint and a reduced on-site installation time was explored for application in a tropical environment. Tree species used in the pilot studies were Talipariti tiliaceum (TT1) and Sterculia macrophylla (TT2). Both of the MBTs could effectively remove total suspended solids (TSS), total phosphorus (TP), zinc, copper, cadmium, and lead with removal efficiencies of greater than 90%. Total nitrogen (TN) removal was noted to be significantly higher in the wet period compared to the dry period (p < 0.05). Variation in TN removal between TT1 and TT2 were attributed to the nitrogen uptake and the root formation of the trees species. A field study MBT using Talipariti tiliaceum had a very clean effluent quality, with average TSS, TP, and TN effluent EMC of 4.8 mg/L, 0.04 mg/L, and 0.27 mg/L, respectively. Key environmental factors were also investigated to study their impact on the performance of BMT. It was found that the initial pollutant concentration, the dissolved fraction of influent pollutants, and soil moisture affect the performance of the MBT. Based on the results from this study, the MBT demonstrates good capability in the improvement of stormwater runoff quality
Intro: In Canada, Giardia and Cryptosporidium are the main etiologic agents of waterborne outbreaks and related illness. It has been predicted that climate change will lead to rises in temperature and increases in severity and frequency... more
Intro: In Canada, Giardia and Cryptosporidium are the main etiologic agents of waterborne outbreaks and related illness. It has been predicted that climate change will lead to rises in temperature and increases in severity and frequency of rainfall events and droughts. Therefore, it is important to understand the impacts of these variables on the presence and distribution of Cryptosporidium and Giardia in raw water sources. Objective: The objective of this study is to: a) compare the distribution of Cryptosporidium and Giardia at two sites on the North Saskatchewan River - intakes of E.L. Smith and Rossdale Water Treatment Plants in Edmonton- between 2012 and 2014 (n=21); b) determine if various chemical, physical or biological water quality variables are significantly correlated with Cryptosporidium and Giardia presence in surface water; and c)construct a multivariate regression model to predict presence of Cryptosporidium and Giardia in the North Saskatchewan River when possible. Methods: The enumeration of Cryptosporidium and Giardia was performed using US EPA Method 1623. The collection of physical and chemical water quality variables was performed using Standard Methods, while climactic data was collected from the Environment Canada site. Correlations were determined using Spearman correlations and other non-parametric statistical tests. Results: Results indicate that there was no statistically significant difference between concentrations of Cryptosporidium at the two plant intakes (p =0.06), but there was a statistically significant difference for Giardia concentrations (p = 0.03). Mean number of Cryptosporidium and Giardia at the Rossdale water treatment plant were 6.73 ± 1.09 and 40.00 ±7.42, respectively. Mean number of Cryptosporidium and Giardia at the E. L. Smith water treatment plant were 9.88 ± 2.24 and 33.78 ± 8.94, respectively. The results also show a clear seasonal trend, with protozoan concentrations being highest in the summer time in both years (June-August). Spearman correlations showed a strong positive correlation between Cryptosporidium and Giardia numbers at each site (Rossdale p = <0.0001; Smith p = 0.008). Temperature was positively correlated with both Cryptosporidium and Giardia at both sites with p-values < 0.007. While rainfall and turbidity showed no relationships with Cryptosporidium or Giardia at Rossdale, turbidity showed a strong trend with Cryptosporidium concentrations but not Giardia at EL Smith (p <0.0001). Total coliforms correlated with Cryptosporidium (p = 0.0010) and E. coli (p = 0.0103) at Rossdale but neither correlated with Giardia, and the same trend was not observed at EL Smith. Finally, there was a negative statistically significant relationship between nitrate and Cryptosporidium and Giardia concentrations at both sites, which was much stronger with Giardia than with Cryptosporidium. Relevance: Understanding the prevalence of pathogens in natural ecosystems and the factors that impact their distribution are important factors in development of sound management strategies that limit risk and protect public health. This study elucidates different relationships between potentially pathogenic protozoa and various commonly-monitored water quality variables that could aid in monitoring and predicting source water quality.
Intro: In Canada, Giardia and Cryptosporidium are the main etiologic agents of waterborne outbreaks and related illness. It has been predicted that climate change will lead to rises in temperature and increases in severity and frequency... more
Intro: In Canada, Giardia and Cryptosporidium are the main etiologic agents of waterborne outbreaks and related illness. It has been predicted that climate change will lead to rises in temperature and increases in severity and frequency of rainfall events and droughts. Therefore, it is important to understand the impacts of these variables on the presence and distribution of Cryptosporidium and Giardia in raw water sources. Objective: The objective of this study is to: a) compare the distribution of Cryptosporidium and Giardia at two sites on the North Saskatchewan River - intakes of E.L. Smith and Rossdale Water Treatment Plants in Edmonton- between 2012 and 2014; b) determine if various chemical, physical or biological water quality variables are significantly correlated with Cryptosporidium and Giardia presence in surface water; and c)construct a multivariate regression model to predict presence of Cryptosporidium and Giardia in the North Saskatchewan River when possible. Methods...
ABSTRACT A hydrological routing study for Abu Zirig Marsh was carried out to estimate the hydrological state within the marsh for the Present and future conditions of the marsh. The water surface elevation, area and storage within the... more
ABSTRACT A hydrological routing study for Abu Zirig Marsh was carried out to estimate the hydrological state within the marsh for the Present and future conditions of the marsh. The water surface elevation, area and storage within the marsh at the present and for the future conditions were estimated and the effect of uncontrolling outlets on the hydrological and water quality state of the marsh at the present conditions was specified. The salt mass balance equation was used to estimate the inflow and outflow discharges that required for reducing the effect of evapotranspiration on the water quality and flashing out the accumulated mass of salts and then improving the marsh water quality. This equation was applied on the future conditions of the marsh and inflow and outflow discharges that required for this purposes were estimated. The results of the hydrological routing for the present conditions showed that the maximum water surface area is 79 km 2 which occur during Spring. While it is between 34 to 43 km 2 during Summer and Autumn and it can not be increased during these months since the outlet of the marsh is uncontrolled. The TDS concentration within the marsh increases during the months of high evapotranspiration although the inflow increases during these months. For the future conditions, the inflow discharges required to sustain the restoration requirements must be increased to decrease the deterioration in the marsh water quality. These discharges increase with the increase in the marsh area during the months of high evapotranspiration values.
