9,868 research outputs found

    Influence of low-density polyethylene addition on coking pressure

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    Different amounts of low-density polyethylene (LDPE) were added to a bituminous coal used to produce metallurgical coke. The effect of the plastic waste on the carbonization process and more exactly, on the coking pressure were investigated. A movable wall oven at semi-pilot scale was used for measuring coking pressure generated. It was found that coking pressure increases for low LDPE addition levels (1-3 wt.%); however higher amounts of LDPE reduce coking pressure. To explain this behavior different blends of the coal and the residue were pyrolysed at three different temperatures (450, 500 and 600 C) in a Gray-King apparatus. The results show that LDPE causes a modification in the pyrolysis process and also influences the swelling process of the plastic stage. The increase of the coking pressure at low LDPE addition rates is associated with a less permeable coal plastic layer, which prevents the removal of the decomposition products and causes their retention in the semicoke matrix, evolving them in the post-plastic stage. Coking pressure decrease at high LDPE addition rates can be due to the charge shrinkage and the better permeability to the migration of oil components, which suggest a lower interaction between the coal and the LDPE. A delay in the degradation of LDPE is confirmed by the data provided by DRIFT and SEM

    Congruent and Incongruent Corticospinal Activations at the Level of Multiple Effectors

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    Motor resonance is defined as the subliminal activation of the motor system while observing actions performed by others. However, resonating with another person's actions is not always an appropriate response: In real life, people do not just imitate but rather respond in a suitable fashion. A growing body of neurophysiologic studies has demonstrated that motor resonance can be overridden by complementary motor responses (such as preparing a precision grip on a small object when seeing an open hand in sign of request). In this study, we investigated the relationship between congruent and incongruent corticospinal activations at the level of multiple effectors. The modulation of MEPs evoked by single-pulse TMS over the motor cortex was assessed in upper and lower limb muscles of participants observing a soccer player performing a penalty kick straight in their direction. Study results revealed a double dissociation: Seeing the soccer player kicking the ball triggered a motor resonance in the observer's lower limb, whereas the upper limb response afforded by the object was overridden. On the other hand, seeing the ball approaching the observers elicited a complementary motor activation in upper limbs while motor resonance in lower limbs disappeared. Control conditions showing lateral kicks, mimicked kicks, and a ball in penalty area were also included to test the motor coding of object affordances. Results point to a modulation of motor responses in different limbs over the course of action and in function of their relevance in different contexts. We contend that ecologically valid paradigms are nowadays needed to shed light on the motor system functioning in complex forms of interaction

    Relevance of the composition of municipal plastic wastes for metallurgical coke production

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    This study is concerned with the effects of the composition of mixed plastic wastes on the thermoplastic properties of coal, the generation of coking pressure and the quality of the resulting cokes in a movable wall oven at semipilot scale. The mixed plastic wastes were selected to cover a wide spectrum in the relative proportions of high- and low-density polyethylenes (HDPE and LDPE), polypropylene (PP), polystyrene (PS) and polyethylene terephthalate (PET). From the results it was deduced that the reduction in Gieseler fluidity in the coal blend is linked to the total amount of polyolefins in the waste. It was also found that these thermoplastics increase the pressure exerted against the wall in the course of the coking process and that coke quality is maintained or even improved. However, when the level of aromatic polymers such PS and PET are increased at the expense of polyolefins, the coking pressure decreases. Thus, the amount of aromatic polymers such as PS and PET in the waste is critical, not only for controlling Gieseler fluidity and coking pressure, but also for avoiding deterioration in coke quality (reactivity towards CO CRI and mechanical strength of the partially-gasified coke CSR). An amount of polyolefins in the waste lower than 65 wt.% for a secure coking pressure is established

    Does Inward Foreign Direct Investment Boost the Productivity of Domestic Firms?

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    Are there productivity spillovers from FDI to domestic firms, and, if so, how much should host countries be willing to pay to attract FDI? To examine these questions we use a plant-level panel covering U.K. manufacturing from 1973 through 1992. Across a wide range of specifications, we estimate a significantly positive correlation between a domestic plant's TFP and the foreign-affiliate share of activity in that plant's industry. This is consistent with positive FDI spillovers. We do not generally find significant effects on plant TFP of the foreign-affiliate share of activity in that plant's region. Typical estimates suggest that a 10 percentage-point increase in foreign presence in a U.K. industry raises the TFP of that industry's domestic plants by about 0.5 percent. We also use these estimates to calculate the per-job value of these spillovers. These calculated values appear to be less than per-job incentives governments have granted in recent high-profile cases, in some cases several times less.

    Does Inward Foreign Direct Investment Boost the Productivity of Domestic Firms?

    Get PDF
    Are there productivity spillovers from FDI to domestic firms, and, if so, how much should host countries be willing to pay to attract FDI? To examine these questions we use a plant-level panel covering U.K. manufacturing from 1973 through 1992. Across a wide range of specifications, we estimate a significantly positive correlation between a domestic plant's TFP and the foreign-affiliate share of activity in that plant's industry. This is consistent with positive FDI spillovers. We do not generally find significant effects on plant TFP of the foreign-affiliate share of activity in that plant's region. Typical estimates suggest that a 10 percentage-point increase in foreign presence in a U.K. industry raises the TFP of that industry's domestic plants by about 0.5 percent. We also use these estimates to calculate the per-job value of these spillovers. These calculated values appear to be less than per-job incentives governments have granted in recent high-profile cases, in some cases several times less.Multinational firms, Foreign direct investment, Productivity spillovers

    Predicting Youth Improvement in Community-Based Residential Settings with Practices Derived from the Evidence-Base.

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    Ph.D. Thesis. University of Hawaiʻi at Mānoa 2017
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