Studies on influence of hydrogen and carbon monoxide concentration on reduction progression behavior of molybdenum oxide catalyst

Temperature programmed reduction (TPR) analysis was applied to investigate the chemical reduction progression behavior of molybdenum oxide (MoO₃) catalyst. The composition and morphology of the reduced phases were characterized by X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscopy (FE-SEM). The reduction progression of MoO₃ catalyst was attained with different reductant types and concentration (10% H₂/N₂, 10% and 20% CO/N₂ (%, v/v)). Two different modes of reduction process were applied. The first approach of reduction involved non-isothermal mode reduction up to 700 °C, while the second approach of reduction involved the isothermal mode reduction for 60 min at 700 °C. Hydrogen temperature programmed reduction (H₂-TPR) results showed the reduction progression of three-stage reduction of MoO₃ (Mo⁶⁺ → Mo⁵⁺ → Mo⁴⁺ → Mo⁰) with Mo⁵⁺ and Mo⁴⁺. XRD analysis confirmed the formation of Mo₄O₁₁ phase as an intermediate phase followed by MoO₂ phase. After 60 min of isothermal reduction, peaks of metallic molybdenum (Mo) appeared. Whereas, FESEM analysis showed porous crater-like structure on the surface cracks of MoO₂ layer which led to the growth of Mo phase. Meanwhile, the reduction of MoO₃ catalyst in 10% carbon monoxide (CO) showed the formation of unstable intermediate phase of Mo₉O₂₆ at the early stage of reduction. Furthermore, by increasing 20% CO led to the carburization of MoO₂ phase, resulted in the formation of Mo₂C rather than the formation of metallic Mo, as confirmed by XPS analysis. Therefore, the presented study shows that hydrogen gave better reducibility due to smaller molecular size, which contributed to high diffusion rate and achieved deeper penetration into the MoO₃ catalyst compared to carbon monoxide reductant. Hence, the reduction of MoO₃ in carbon monoxide atmosphere promoted the formation of Mo₂C which was in agreement with the thermodynamic assessment.     

The role of categories and spatial cuing in global-scale location estimates.

Seven independent groups estimated the location of North American cities using both spatial and numeric response modes and a variety of perceptual and memory supports. These supports included having location markers for each city color coded by nation and identified by name, giving participants the opportunity to see and update all their estimates throughout the task, and allowing them to respond directly on a map. No manipulation mitigated the influence of categories on the judgments, but some manipulations improved within-region ordinal accuracy. The data provide evidence that the city and regional levels are independent, spatial and numeric response modalities affect accuracy differently at the different levels, biases at the regional level have multiple sources, and accurate spatial cues improve estimates primarily by limiting the use of global landmarks to partition the response space. Results support J. Huttenlocher, L. V. Hedges, and S. Duncan's (1991) theory of spatial location estimates and extend it to the domain of real-world geography. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Microfluidic arrays for bioimprint of cancer cells

We report the development and characterization of a microfluidics-based bioimprint process using high-density microchannel arrays for cell-culture and polymer delivery. The tubeless PDMS arrays consist of multiple independent microchannels and allow for parallelized bioimprint via automated dispensing and passive pumping. Using the microchannels, a 400 nm thin test pattern was replicated into a methacrylate biopolymer to demonstrate process applicability. Bioimprints of cobalt chloride stimulated Ishikawa endometrial cancer cells exhibiting exocytosis-like pore structures were compared with controls using AFM to exemplify a process application. The devices can be used for high-throughput cell assays, cell developmental studies and the formation of phenotype-specific biomimetic scaffolds.     

Seeing versus imagining movement in depth.

Six undergraduate students participated in 2 experiments to determine whether the same mechanisms are activated during perception of real vs apparent motion. In Exp 1, Ss judged the quality of rigid motion between pairs of 3-dimensional drawings that differed by a rotation in depth. Rated quality of motion decreased with increasing angular disparity between the figures and with decreasing stimulus duration, regardless of whether the figures were vertical or oblique. In Exp 2, Ss participated in a mental rotation task using the same stimuli and angular disparities. Ss took longer to make decisions about obliquely aligned than vertically aligned stimuli. Results imply that perceived vs imagined movement through the same trajectory involves different processes. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Solvent-Aided Crystallization for Biodiesel Purification

The application of solvent-aided crystallization (SAC) is based on the addition of a solvent, here 1-butanol, to crude biodiesel to catalyze the purification process by separating biodiesel from contaminants via crystallization process. Response surface methodology was applied to optimize the process parameters of SAC, represented by biodiesel purity. The purified biodiesel was analyzed by means of gas chromatography-mass spectrometry for the composition of the present fatty acid methyl ester (FAME). Under the predicted optimum process conditions within the experimental ranges for the highest biodiesel purity, the predicted biodiesel purity was 99.375 %.     

Review on Progressive Freeze Concentration Designs

Progressive freeze concentration (PFC) is a process where only a large single ice crystal is formed in the system and grown on the cooling surface so that the separation between the ice crystal and the mother solution is very easy. This makes the system very simple and leads to a lower cost. The conventional setup of PFC produces ice with high purity but lower productivity than suspension freeze concentration (SFC). The volume of ice produced is also usually low. Hence, continued areas of the development for PFC system include the quest for improved productivity and better efficiency. Different kinds of design have been investigated, which are easy to operate and cost-effective besides the ability to obtain high quality of product and better efficiency of the system. The PFC system is recognized as a good alternative if high-quality products can be produced with higher productivity. In this article, previous researches on PFC designs were reviewed for the purpose of providing an understanding on methods of designing a PFC system and also to provide references for future application of PFC.     

Scientometric assessment of engineering in Malaysians universities

There is a world trend for Research Performance Evaluation (RPE), developing of new scientometric indices and examining of their application. Consequently, concerns and anomalies arise about the convergent validity and reliability of these indices for the decision making purposes. This is especially prevalent in the region/countries/disciplines having less or emerging trends of publishing and getting citations. The present scientometric study addresses usefulness of the most noted metric h-index along with other selected indicators in the field of Engineering in Malaysians universities. To understand, the role of this metric if any, we examined the functional correlation, predictive value and its relationship with national assessment criteria. Results report that this indicator has good potential to work alone, ease in use and robust to get a broader snapshot for positioning and performance evaluation. However, for better decision making purpose, this can be used for broader contextual peer assessment process along with other indicators. Its validity is further checked with two size independent institutional h-indices: h_G–H and h_m.     

Reasoning about geography.

To understand the nature and etiology of biases in geographical judgments, the authors asked people to estimate latitudes (Experiments 1 and 2) and longitudes (Experiments 3 and 4) of cities throughout the Old and New Worlds. They also examined how people's biased geographical judgments change after they receive accurate information ("seeds") about actual locations. Location profiles constructed from the pre- and postseeding location estimates conveyed detailed information about the representations underlying geography knowledge, including the subjective positioning and subregionalization of regions within continents; differential seeding effects revealed between-region dependencies. The findings implicate an important role for conceptual knowledge and plausible-reasoning processes in tasks that use subjective geographical information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Progressive Freeze Concentration for Volume Reduction of Produced Water and Biodiesel Wastewater

One way to conserve fresh water resources is by reusing water from wastewater. For instance, water can be removed from wastewater through formation of ice crystal layers by progressive freeze concentration (PFC). The application of PFC to remove water from produced water and biodiesel wastewater was assessed through the final concentration of concentrated wastewater and purity of melted ice crystals. No PFC study has been done on these applications. In order to evaluate the efficiency of PFC, the effective partition constant (K) and separation efficiency (S_E) were calculated for the effect of stirring rate and coolant temperature. The results demonstrate that PFC is a more practical method for produced water, as compared to biodiesel wastewater which is based on the value of low K and high S_E.