This research aimed to enhance the column bioleaching recovery of uranium ore by Acidithiobacillus ferrooxidans.Seven factors were examined for their significance on bioleaching using a Plackett-Burman factorial desig...This research aimed to enhance the column bioleaching recovery of uranium ore by Acidithiobacillus ferrooxidans.Seven factors were examined for their significance on bioleaching using a Plackett-Burman factorial design.Four significant variables([Fe2+]initial,pH,aeration rate and inoculation percent)were selected for the optimization studies.The effect of these variables on uranium bioleaching was studied using a central composite design(CCD).The optimal values of the variables for the maximum uranium bioleaching recovery(90.27±0.98)%were as follows:[Fe2+]initial=2.89g/L,aeration rate420mL/min,pH1.45and inoculation6%(v/v).[Fe2+]initial was found to be the most effective parameter.The maximum uranium recovery from the predicted models was92.01%.This value was in agreement with the actual experimental value.The analysis of bioleaching residue of uranium ore under optimum conditions confirmed the formation of K-jarosite on the surface of minerals.By using optimal conditions,uranium bioleaching recovery is increased at column and jarosite precipitation is minimized.The kinetic model showed that uranium recovery has a direct relation with ferric ion concentration.展开更多
In a coupled laser system, the dynamics of the receiving laser is investigated when two separate transmitting lasers are injected into the receiving laser with different coupling strengths. It is shown that the phenom...In a coupled laser system, the dynamics of the receiving laser is investigated when two separate transmitting lasers are injected into the receiving laser with different coupling strengths. It is shown that the phenomenon of preference of chaotic synchronization appears under appropriate coupling conditions. The receiving laser will entrain the pulses of either one or both transmitting lasers when the coupling is strong while it keeps its own dynamics when the coupling is weak.展开更多
Spontaneous combustion(sponcom) is one of the issues of concern with the blasting gallery(BG) method of coal mining and has the potential to cause fires, and impact on production and safety, greenhouse gas(GHG) emissi...Spontaneous combustion(sponcom) is one of the issues of concern with the blasting gallery(BG) method of coal mining and has the potential to cause fires, and impact on production and safety, greenhouse gas(GHG) emissions and huge costs involved in controlling the aftermath situations. Some of the research attempts made to prevent and control coal mine fires and spontaneous combustion in thick seams worked with bord and pillar mining methods are presented in this paper. In the study, computational fluid dynamics(CFD) modelling techniques were used to simulate and assess the effects of various mining methods, layouts, designs, and different operational and ventilation parameters on the flow of goaf gases in BG panels. A wide range of parametric studies were conducted to develop proactive strategies to control and prevent ingress of oxygen into the goaf area preventing spontaneous combustion and mine fires.展开更多
Kant＇s Humanity Formula of the Categorical Imperative is arguably its most widely preferred formulation, having been defended as a moral principle and employed in the evaluation of particular moral problems by a numb...Kant＇s Humanity Formula of the Categorical Imperative is arguably its most widely preferred formulation, having been defended as a moral principle and employed in the evaluation of particular moral problems by a number of leading contemporary ethicists. For them and many other readers of Kant, the idea that we are not to treat persons as mere means to our own ends but are rather to respect their rational agency as intrinsically valuable holds great promise for qualifying as, in Kant＇s words, ＂the supreme principle of morality.＂ In the present paper I argue that the Humanity Formula cannot deliver on this promise. After setting forth three conditions of adequacy for any genuine supreme principle of morality, I argue that the Humanity Formula, on three textually grounded interpretations each of which has been advocated by a prominent Kantian ethicist, does not satisfy these conditions. Whichever of these textually grounded interpretations is taken, the Humanity Formula is open to compelling counterexamples.展开更多
We consider a behavioural model of an animal choosing between two activities, based on positive feedback, and exa- mine the effect of introducing cross inhibition between the motivations for the two activities. While ...We consider a behavioural model of an animal choosing between two activities, based on positive feedback, and exa- mine the effect of introducing cross inhibition between the motivations for the two activities. While cross-inhibition has pre- viously been included in models of decision making, the question of what benefit it may provide to an animal＇s activity selection behaviour has not previously been studied. In neuroscience and in collective behaviour cross-inhibition, and other equivalent means of coupling evidence-accumulating pathways, have been shown to approximate statistically-optimal decision-making and to adaptively break deadlock, thereby improving decision performance. Switching between activities is an ongoing decision process yet here we also find that cross-inhibition robustly improves its efficiency, by reducing the frequency of costly switches between behaviours .展开更多
基金the Tarbiat Modares University & Nuclear Science and Technology Research Institute for their financial support
文摘This research aimed to enhance the column bioleaching recovery of uranium ore by Acidithiobacillus ferrooxidans.Seven factors were examined for their significance on bioleaching using a Plackett-Burman factorial design.Four significant variables([Fe2+]initial,pH,aeration rate and inoculation percent)were selected for the optimization studies.The effect of these variables on uranium bioleaching was studied using a central composite design(CCD).The optimal values of the variables for the maximum uranium bioleaching recovery(90.27±0.98)%were as follows:[Fe2+]initial=2.89g/L,aeration rate420mL/min,pH1.45and inoculation6%(v/v).[Fe2+]initial was found to be the most effective parameter.The maximum uranium recovery from the predicted models was92.01%.This value was in agreement with the actual experimental value.The analysis of bioleaching residue of uranium ore under optimum conditions confirmed the formation of K-jarosite on the surface of minerals.By using optimal conditions,uranium bioleaching recovery is increased at column and jarosite precipitation is minimized.The kinetic model showed that uranium recovery has a direct relation with ferric ion concentration.
文摘In a coupled laser system, the dynamics of the receiving laser is investigated when two separate transmitting lasers are injected into the receiving laser with different coupling strengths. It is shown that the phenomenon of preference of chaotic synchronization appears under appropriate coupling conditions. The receiving laser will entrain the pulses of either one or both transmitting lasers when the coupling is strong while it keeps its own dynamics when the coupling is weak.
文摘Spontaneous combustion(sponcom) is one of the issues of concern with the blasting gallery(BG) method of coal mining and has the potential to cause fires, and impact on production and safety, greenhouse gas(GHG) emissions and huge costs involved in controlling the aftermath situations. Some of the research attempts made to prevent and control coal mine fires and spontaneous combustion in thick seams worked with bord and pillar mining methods are presented in this paper. In the study, computational fluid dynamics(CFD) modelling techniques were used to simulate and assess the effects of various mining methods, layouts, designs, and different operational and ventilation parameters on the flow of goaf gases in BG panels. A wide range of parametric studies were conducted to develop proactive strategies to control and prevent ingress of oxygen into the goaf area preventing spontaneous combustion and mine fires.
文摘Kant＇s Humanity Formula of the Categorical Imperative is arguably its most widely preferred formulation, having been defended as a moral principle and employed in the evaluation of particular moral problems by a number of leading contemporary ethicists. For them and many other readers of Kant, the idea that we are not to treat persons as mere means to our own ends but are rather to respect their rational agency as intrinsically valuable holds great promise for qualifying as, in Kant＇s words, ＂the supreme principle of morality.＂ In the present paper I argue that the Humanity Formula cannot deliver on this promise. After setting forth three conditions of adequacy for any genuine supreme principle of morality, I argue that the Humanity Formula, on three textually grounded interpretations each of which has been advocated by a prominent Kantian ethicist, does not satisfy these conditions. Whichever of these textually grounded interpretations is taken, the Humanity Formula is open to compelling counterexamples.
文摘We consider a behavioural model of an animal choosing between two activities, based on positive feedback, and exa- mine the effect of introducing cross inhibition between the motivations for the two activities. While cross-inhibition has pre- viously been included in models of decision making, the question of what benefit it may provide to an animal＇s activity selection behaviour has not previously been studied. In neuroscience and in collective behaviour cross-inhibition, and other equivalent means of coupling evidence-accumulating pathways, have been shown to approximate statistically-optimal decision-making and to adaptively break deadlock, thereby improving decision performance. Switching between activities is an ongoing decision process yet here we also find that cross-inhibition robustly improves its efficiency, by reducing the frequency of costly switches between behaviours .
