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Physico-chemical Characteristics of a Gold Mining Tailings Dam Wastewater

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Journal of Environmental Science and Engineering(A) 2013年第8期2卷 469-475页

作者： Mike Agbesi Acheampong jackson adiyiah Ebenezer David Okwaning Ansa Department of Chemical Engineering Kumasi Polytechnic Kumasi 854 Ghana Department of Field Operations Environmental Protection Agency Sunyani 1505 Ghana Department of Environmental Biology and Health Water Research Institute CSIR (Council for Scientific and Industrial Research) Aehimota Accra AH 38 Ghana

The study was conducted on the status of the quality of wastewater from the tailings dam of Central Africa Gold Limited in Bibiani, Ghana, to ascertain the level of contamination of the wastewater. The tailings dam stores process effluent from the gold extraction plant. Wastewater samples taken from the tailings dam were analyzed for physico-chemical characteristics. Arsenic, iron and cyanide were identified as the major pollutants in the tailings dam wastewater with average concentrations of 4.5, 25.2 and 11.1 mg.L1, respectively. Arsenic, iron and free CN （cyanide） concentrations in the process effluent exceeded the Ghana EPA discharge limits of 0.2, 2 and 0.2 ***, respectively. High conductivity, total dissolved solids, sulphate and ammonium were found in the wastewater studied. The tailings dam serves as a natural reservoir that removes most of the total suspended solids and the turbidity, resulting in the improvement in the aesthetic appeal of the wastewater. Nonetheless, arsenic, iron and cyanide concentrations were still high and hence the wastewater cannot be discharged into the environment without prior treatment.

关键词： Cyanide heavy metals physico-chemical characteristics gold mine wastewater tailings dam.

The Effect of Industrial Effluents on the Quality of Onukpawahe Stream, Tema-Ghana

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Journal of Environmental Science and Engineering(B) 2016年第10期5卷 457-475页

作者： Abdalla Abubakari Anyemedu Fredrick Oppong-Kyekyeku Donkor Emmanuel jackson adiyiah Nyantakyi Environmental Protection Agency (EPA) Accra M326 Ghana Department of Civil Engineering Kwame Nkrumah University of Science and Technology PMB Kumasi Ghana Environmental Protection Agency (EPA) Sunyani 1505 Brong-Ahafo Ghana

Industrial effluents discharged into surface water body present a high percent of pollution in Ghanaian streams and rivers. The current study assessed the effects of industrial effluent on the quality of Onukpawahe stream which receives industrial effluents from the Tema Metropolis. Effluent samples were collected from six （6） selected industries and the water samples were collected from sixteen （16） different locations on the Onukpawahe stream. Various physico-chemical parameters such as BOD, TDS, Conductivity, COD, pH, TSS, Turbidity, Temperature, Colour, Sulphate, Phosphate, Ammonia and Nitrate were analysed during the current investigation. The average values of all the physico-chemical parameters （except pH and DO） were all above the EPA sector specific effluent guidelines. It was established in the study that the industries have polluted the stream and have grievously compromised the quality of the Onukpawahe stream. The surface water and industrial effluent must be monitored by the authorities in order to prevent further degradation of the river quality.

关键词： Onukpawahe stream industrial effluent water quality physico-chemical parameters EPA limits.

Wastewater Quality Assessment of a Petroleum Refinery in Ghana

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Journal of Environmental Science and Engineering(B) 2013年第9期2卷 514-520页

作者： Frederick Kobina Nkrumah Mike Agbesi Acheampong Ebenezer David Okwaning Ansa jackson adiyiah Department of Chemical Engineering Kumasi Polytechnic Kumasi 854 Ghana CSIR Water Research Institute Aehimota Accra Ghana Department of Field Operations Environmental Protection Agency Sunyani Ghana

TOR （Tema oil refinery） is the only petroleum refinery in Ghana. To assess the quality of the wastewater, wastewater samples taken from three points of discharge into the treatment plant and the treated effluent were analyzed for physico-chemical characteristics. The levels of the pH, temperature, conductivity, COD （Chemical Oxygen Demand）, TDS （Total Dissolved Solids）, TSS （Total Suspended Solids） and phenol were assessed from January to June, 2011. The results obtained indicate varied levels of contaminants in both the untreated and treated wastewater. The average values of the treated effluent parameters analyzed were 38 ℃, 6,258 μ***-1, 314 mg-L-1, 115 mg.L-1, 2,689 mg-L-1 and 1 mg.L-1 for the temperature, conductivity, COD, TDS, TSS and phenol, respectively. The results suggest that both the raw wastewater and the treated effluent did not meet the discharge limit set by Ghana Environmental Protection Agency. Therefore, the treated effluent required additional treatment before it can be discharged into the environment. This suggests that the wastewater treatment plant of TOR is ineffective for the type of wastewater produced.

关键词： Industrial wastewater petroleum effluent pollutants Tema oil refinery Ghana.

Escherichia coil Removal in Tropical Oligotrophic and Eutrophic Lakes

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Journal of Environmental Science and Engineering(A) 2013年第12期2卷 719-724页

作者： Ebenezer David Okwaning Ansa Anthonia Helga Andoh Gloria Akosua Ansa jackson adiyiah MikeAgbesi Acheampong Water Research Institute Council for Scientific & Industrial Research Accra Ghana Department of Public Health University Hospital Accra Ghana Department of Field Operations Environmental Protection Agency Sunyani Ghana Department of Chemical Engineering Kumasi Polytechnic Kumasi Ghana

The mechanisms by which oligotrophic and eutrophic lakes rid itself of Escherichia coli or faecal coliforms are still not clearly understood. This study sought to review the various means by which E. coli or faecal coliforms are inactivated or removed in lakes. The review cited temperature, solar radiation, predation, starvation, attachment and sedimentation as key factors that aid the removal of E. coli in lakes. In eutrophic lakes additional factors such as the role of algal biomass may play a role due to increased pH and dissolved oxygen levels attributed to algal presence. Algal toxins or exudates may also play a role although this is still under debate. The interactive effect of two or more of these factors on E. coli inactivation and the relative importance of these mechanisms on E. coli removal are still not known. Areas for further research include the role of algae in sedimenting E. coli or faecal coliforms and the possible role of algal exudates on E. coli inactivation.

关键词： Predation sedimentation solar radiation starvation temperature.

Calcium channels caught in peripheral glia’s tug-of-war on axon regeneration in Drosophila

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Neural Regeneration Research 2025年第2期20卷 475-476页

作者： jackson Powell Tobias Steinschaden Rose Horowitz Yuanquan Song Raymond G.Perelman Center for Cellular and Molecular Therapeutics The Children’s Hospital of PhiladelphiaPhiladelphiaPAUSA The Neuroscience Graduate Group University of PennsylvaniaPhiladelphiaPAUSA Department of Pathology and Laboratory Medicine University of PennsylvaniaPhiladelphiaPAUSA Medical University of Vienna Center for Brain ResearchDepartment of NeuroimmunologyViennaAustria

Neural damage or degeneration is at the crux of many diseases,and treatment of these diseases will require the development of therapeutics to enhance and guide neural *** intrinsic and extrinsic factors dictate a neuron’s ability to regenerate,and the combination of these factors results in the great regenerative capacity of the peripheral nervous system(PNS)and the poor regenerative capacity of the central nervous system(CNS)following *** the core of a neuron’s function is its ability to relay electrochemical signals,and a neuron’s excitability is a key factor in its ability to *** works have focused on the changes in neuronal electrophysiological properties,firing patterns,and ion flux after injury,which differentially activate signaling pathways at the core of *** role of glia in neuron regeneration has long been studied.

关键词： degeneration firing system

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Piling up multidecker pyrgos[n]cages as antibacterial materials

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Science China Materials 2025年第01期 314-316页

作者： Miguel A.Liuzzi-Vaamonde jackson B.Lancaster Samantha A.Mason Yuanning Feng Department of Chemistry and Biochemistry The University of Oklahoma

The development of antibiotics is regarded as one of the most significant scientific advances in modern medicine. Before the commercialization of antibiotics, infectious diseases were catastrophic throughout history [1]. Penicillin was used to treat serious infections in the 1940s, but unfortunately, with the introduction of antibiotics came the emergence of antibiotic resistance [2,3]. Evolved and adapted methicillin-resistant Staphylococcus aureus (MRSA) strains are presently impacting community and healthcare systems across the globe [4].

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Concept of a Pitot Tube Able to Detect Blockage by Ice, Volcanic Ash, Sand and Insects, and to Clear the Tube

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Photonic Sensors 2015年第4期5卷 298-303页

作者： David A. jackson School of Physical Sciences Applied Optics Groups University of Kent UK

A conceptual coaxial Pitot tube （PT） has been developed using fiber optic sensors combined with actuators to monitor and maintain its correct operation under different environmental conditions. Experiments were performed showing that the dynamic and static tubes can be cleared of ice. It was also demonstrated that the dynamic tube could be cleared of dust and sand which was not the case for the static tube in the coaxial configuration. An approach was proposed to overcome this problem involving a conventional configuration where the static tube was operated independently orthogonal to the dynamic tube, and a second set of sensors and actuators was used. Sensors and associated actuators were developed for temperature and intensity for a linear PT. The aim of this work is to propose a solution for a problem that has caused the loss of the lives of many passengers and crew of aircraft. Resources were not available to test a full implementation of a PT incorporating the proposed modifications.

关键词： Pitot tube instrumentation FBG spectrometer pressure temperature optical intensity

Effect of distribution shape on the melting transition, local ordering,and dynamics in a model size-polydisperse two-dimensional fluid

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Chinese Physics B 2024年第7期33卷 419-428页

作者： jackson Pame Lenin SShagolsem Department of Physics National Institute of Technology ManipurImphalIndia

We study the effect of particle size polydispersity(δ) on the melting transition(T*), local ordering, solid–liquid coexistence phase and dynamics of two-dimensional Lennard–Jones fluids up to moderate polydispersity by means of computer simulations. The particle sizes are drawn at random from the Gaussian(G) and uniform(U) distribution *** these systems, we further consider two different kinds of particles, viz., particles having the same mass irrespective of size, and in the other case the mass of the particle scales with its size. It is observed that with increasing polydispersity,the value of T*initially increases due to improved packing efficiency(φ) followed by a decrease and terminates at δ ≈8%(U-system) and 14%(G-system) with no significant difference for both mass types. The interesting observation is that the particular value at which φ drops suddenly coincides with the peak of the heat capacity(CP) curve, indicating a transition. The quantification of local particle ordering through the hexatic order parameter(Q_6), Voronoi construction and pair correlation function reveals that the ordering decreases with increasing δ and T. Furthermore, the solid–liquid coexistence region for the G-system is shown to be comparatively wider in the T –δ plane phase diagram than that for the U system. Finally, the study of dynamics reveals that polydisperse systems relax faster compared to monodisperse systems;however, no significant qualitative differences, depending on the distribution type and mass polydispersity, are observed.

关键词： polydispersity ordering phase diagram dynamics

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Nanostructured grinding wheels for ultra-precision engineering applications

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Nanotechnology and Precision Engineering 2021年第3期4卷 63-75页

作者： M.J.jackson Integrated Studies College of Technology and AviationKansas State UniversitySalinaKansas 67401USA

Manufacturers face challenges when dealing with abrasives that lose roundness,wear excessively,and suffer from pitting of the surface of the grinding wheel that needs rectification using dressing *** abrasive grits manufactured by hybrid fusion processes and by sintering/extrusion/printing processes are found to reduce pitting quite *** phenomenon of wheel collapse is increasing and cycle times developed during the grinding of aerospace alloys are much smaller compared to using conventional *** paper reviews the phenomenon of wheel collapse induced by pitting and takes a critical look at the production and analysis of hybrid fused and printed/sintered abrasives.A mathematical analysis is carried out of the diffusion of primary and secondary phases due to mechanical and ultrasonic agitation with the aim of producing abrasive grits with improved strength and *** developments in extruded,printed,and sintered grits for use in precision grinding applications are critically *** paper concludes by explaining how such abrasives are used in practice by industrial manufacturers of high-precision products.

关键词： Nanotechnology Abrasives Alloys Finishing Grinding Machining

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