Crystallization and thermal stability of polypropylene/multi-wall carbon nanotube nanocomposites

Polypropylene (PP)/multi-wall carbon nanotube (MWCNT) nanocomposites were prepared via a melt compounding method using a twin-screw extruder. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to study the crystallization and thermal stability of the nanocomposites. The DSC analysis results revealed that the existence of MWCNTs in a PP matrix, which acted as a nucleating agent enhancing the crystallization process of PP matrix. This behaviour was manifested by an increase in the crystallization temperature and crystallinity index of the nanocomposites. Additionally, the TGA results showed that the addition of MWCNTs dramatically increased the thermal stability of the PP/MWCNT nanocomposites. Generally, MWCNT type C-70P showed improved crystallization and better thermal stability of the nanocomposites compared to type C-150P.     

Analysis of regional environment and regional innovation strategy based on cybernetics

In this paper, based on the perspective of carbon emissions, the regional environment and regional innovation strategies were analyzed by using cybernetics. The main idea was to calibrate the diesel engine simulation model with predictive function based on the data collected from the bench test, and then according to the simulation model, the genetic algorithm was applied to optimize the EGR parameters and fuel injection parameters with the target of emission generation and output torque. First of all, the combustion process and emission performance of diesel engine with internal exhaust re-circulation were studied by genetic algorithm, and the genetic algorithm model was constructed. Then, the genetic algorithm program was written based on Matlab. In addition, taking the NOx emission as the target, and the Soot emission and the output torque of the original machine as constraints, through the joint simulation of Matlab and GT-Power, the EGR parameters and fuel injection parameters of the 10% to 50% load conditions were optimized at the speed of 1500 r/min and 2000 r/min. Finally, the validity of this method was verified and analyzed.     

Magnetic properties of Mn-doped armchair ZnO nanotubes: a Monte Carlo study

The magnetic properties of a Mn-doped armchair ZnO nanotube have been studied using Monte Carlo simulation. The variation of zero-field-cooled and field-cooled magnetisation with reduced temperatures for different values of the dilution x (where x is the Mn concentration: Zn_1?xMn_xO) are given. The freezing temperatures and magnetisation vs. crystal field are calculated for different dilutions x. Finally, the hysteresis loops for different dilutions and temperatures are given for a fixed reduced temperature and crystal field. Superparamagnetic behaviour is observed for small values of x and low temperatures.     

One-step synthesis of bulk quantities of graphene from graphite by femtosecond laser ablation under ambient conditions

Bulk synthesis of few-layer graphene (FLG) for industrial applications still remains a challenge for researchers. Here, we report a very simple technique for bulk synthesis of FLG by femtosecond laser ablation of graphite powder suspended in ethanol without the requirement of a controlled environment. Graphite powder, with an average particle size <20 μm, was suspended uniformly in ethanol and ablated at room temperature using fs pulses (wavelength ~800 nm and an input beam diameter ~8 mm) followed by ultrasonication to obtain FLG with a lateral size of ~1 μm. Raman spectroscopy and high-resolution transmission electron microscopy data confirmed the nature and morphology of the FLG. The quality and number of layers in the FLG could be controlled by tuning the laser parameters.     

Investigations of the optical and EPR spectra for VO2+ in NaHC2O4 · H2O single crystals

Theoretical calculations of the optical absorption and electron paramagnetic resonance (EPR) spectra of VO²⁺ in NaHC₂O₄?·?H₂O single crystals were performed using the complete diagonalization energy matrix method (CDM) and the perturbation theory method (PTM) for the 3d ¹ electronic configuration. The calculated results are in good agreement with experimental results. The negative signs of hyperfine structure constants A _∥ and A _⊥ for VO²⁺ in NaHC₂O₄·H₂O single crystals are suggested from the calculations. Comparison of the two calculation methods indicates that the PTM is a good approximation of CDM and that both theoretical methods are valid in interpretation of the optical and EPR spectra for VO²⁺ ions in NaHC₂O₄?·?H₂O crystals.     

Sailing for New Atlantis

Several academic traditions have addressed epistemological objectivity and/or partisanship in the study of technoscientific controversies. On the one hand, positivist and relativist scholars agree that the political commitments of the social researcher should not impinge on scientific enquiry, while on the other hand, feminist and Marxist scholars not only take stands in diverse technoscientific debates, but even claim their agendas to be more credible than those of orthodox scientists. Such perspectives stress that all research is partisan in one way or another because it involves questions of who controls, manipulates, and establishes decisions, facts, and knowledge. With this in mind, it is possible to identify different forms of partisan research including capture by participants, de facto and overt partisanship, and mercenary scholarship. These different forms of partisan scholarship are characterised by differences in the motives underlying epistemological choices of research topic and method, personal commitments to the fields studied, use of research findings in controversies, and positioning of results in wider debates. Two examples help to illustrate partisan scholarship: first, a study of new technologies for managing climate change (carbon dioxide capture and storage); and second, the construction of the new underground metro system in Athens and its accommodation of accessibility standards. Both cases entail partisan positions and raise similar concerns about the orthodox epistemological assumptions underpinning sociotechnical systems, especially when it comes to technoscientific controversies. Supporting STS partisan scholarship, therefore, enables greater social and democratic engagement with technoscientific development.     

Inhibition of endogenous carbon monoxide production induces transient retention losses in the day-old chick when trained using a single trial passive avoidance learning task

Carbon monoxide (CO) is most often thought of as an exogenous toxin rather than as a possible endogenous nootrope. However, a limited number of studies have suggested that CO is necessary in memory processing for at least some tasks. While nitric oxide (NO) and CO are known activators of guanylyl cyclase (GC), only the effect of NO on GC has been extensively investigated as a mechanism underlying memory processing. The aim of the present study was to determine if inhibition of CO production would have an effect on memory processing. Using chicks trained on a single trial passive avoidance task, inhibition of CO production using zinc (II) deuteroporphyrin IX 2,4-bis ethylene glycol (ZnBG; 5 microM) resulted in two transient retention losses occurring at around 40 and 130 min post-training. The timing of these transient retention losses was similar to those observed following inhibition of GC, using the same species and task in a previous study. This supports the notion that CO is necessary in memory processing for this task and may act through a GC-dependent mechanism. As ZnBG also directly inhibits GC or nitric oxide synthase (NOS) at high concentrations, a second experiment was carried-out to confirm the specificity of ZnBG for heme oxygenase (HO) at the concentration used. The action of ZnBG was challenged with the HO agonist hemin (100 microM) and the transient deficits were abolished. This confirmed that the action of ZnBG on memory was through a CO-related mechanism rather than directly on GC or NOS. In this way the specificity of ZnBG (5 microM) for HO could be confirmed. The results support a role for endogenous CO in memory processing, possibly through activation of GC. In addition, the transient retention losses observed following administration of ZnBG suggest that CO may be necessary for memory retrieval and not formation as previously thought.     

Subjective and physiological responses to the 35% carbon dioxide challenge in healthy and non-clinical control populations: a meta-analysis and systematic review

Background/Rationale: The carbon dioxide (CO₂) challenge has been reliably used in laboratory settings as a panicogen in clinical populations. However, the magnitude of these effects on healthy and non-clinical control populations are not clear. The aim of this meta-analysis and systematic review is to provide quantitative estimates of those effects. Specifically, the current paper will evaluate the relative efficacy of the CO₂ challenge in eliciting both subjective and physiological arousal in healthy and non-clinical control populations.

Method: A total of 16 articles with 35 independent samples were included in the meta-analysis, while 37 studies with 74 independent samples were included in the systematic review.

Results: Both the meta-analysis and systematic review found the CO₂ challenge to elicit an increase in subjective distress via self-reported anxiety and fear. Physiological responses via blood pressure and heart rate were heterogeneous in studies sampled, with no significant changes observed across studies. Moderator analyses revealed the variations in findings may be attributed to participant screening and invasive sampling.

Discussion: Findings highlight the CO₂ challenge as a useful tool in the provocation of subjective distress. Implications for both the use of the CO₂ challenge and its anticipated effects in healthy and non-clinical control populations are discussed.