Microalgal species selection for biodiesel production based on fuel properties derived from fatty acid profiles

Physical and chemical properties of biodiesel are influenced by structural features of the fatty acids, such as chain length, degree of unsaturation and branching of the carbon chain. This study investigated if microalgal fatty acid profiles are suitable for biodiesel characterization and species selection through Preference Ranking Organisation Method for Enrichment Evaluation (PROMETHEE) and Graphical Analysis for Interactive Assistance (GAIA) analysis. Fatty acid methyl ester (FAME) profiles were used to calculate the likely key chemical and physical properties of the biodiesel [cetane number (CN), iodine value (IV), cold filter plugging point, density, kinematic viscosity, higher heating value] of nine microalgal species (this study) and twelve species from the literature, selected for their suitability for cultivation in subtropical climates. An equal-parameter weighted (PROMETHEE-GAIA) ranked Nannochloropsis oculata, Extubocellulus sp. and Biddulphia sp. highest; the only species meeting the EN14214 and ASTM D6751-02 biodiesel standards, except for the double bond limit in the EN14214. Chlorella vulgaris outranked N. oculata when the twelve microalgae were included. Culture growth phase (stationary) and, to a lesser extent, nutrient provision affected CN and IV values of N. oculata due to lower eicosapentaenoic acid (EPA) contents. Application of a polyunsaturated fatty acid (PUFA) weighting to saturation led to a lower ranking of species exceeding the double bond EN14214 thresholds. In summary, CN, IV, C18:3 and double bond limits were the strongest drivers in equal biodiesel parameter-weighted PROMETHEE analysis.

Electropolishing of polycrystalline YBa2Cu3O7-δ to meet the need for sharp needle geometry

An electropolishing method has been developed for preparing sharp needles from polycrystalline YBa2Cu3O7-δ by modifying a recipe for TEM specimen preparation. The method is characterized by a polishing temperature of below 0°C, a non-acidic electrolyt and an even removal of the constituent phases. An approach was employed of combining I-V measurements for polishing process and microscopical observation of surface morphology in finding optimum polishing conditions. TEM evidenced that no preferential attack appeared to grain boundaries. X-ray diffractometry and electron diffraction implied that no change in oxygen content occurred during electropolishing. The sharpness of the tip was examined by field-ion microscopy.

Effects of PtO2 and CeO2 additives on the microstructures of the quenched melts of Y-Ba-Cu-O materials

The microstructures of the quenched melts of samples of Y123 and Y123+15-20 mol% Y211 with PtO2 and CeO2 additives have been examined with optical microscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectrometry (EDS) and X-ray Diffractometry (XRD). Significantly higher temperatures are required for the formation of dendritic or lamellar eutectic patterns throughout the samples with PtO2 and CeO2 additives as compared to samples without additives. The BaCuO2 (BCl) phase appears first in solid form and, instead of rapidly melting, is slowly dissolving or decomposing in the oxygen depleted melt. PtO2 and CeO2 additives slow down or shift to higher temperatures the dissolution or decomposition process of BCl. A larger fraction of BCl in solid form explains why samples with additives have higher viscosities and hence lower diffusivities than samples without additives. There is also a reduction in the Y solubility to about half the value in samples without additives. The mechanism that limits the Ostwald ripening of the Y211 particles is correlated to the morphology of the quenched partial melt. It is diffusion controlled for a finely mixed morphology and interface-controlled when the melt quenches into dendritic or lamellar eutectic patterns. The change in the morphology of the Y211 particles from blocky to acicular is related to an equivalent undercooling of the Y-Ba-Cu-O partial melt, particularly through the crystallization of BCl.

Galvanic Replacement of Semiconductor Phase I CuTCNQ Microrods with KAuBr4 to Fabricate CuTCNQ/Au Nanocomposites with Photocatalytic Properties

In this study, the reaction of semiconductor microrods of phase I copper 7,7,8,8-tetracyanoquinodimethane (CuTCNQ) with KAuBr4 in acetonitrile is reported. It was found that the reaction is redox in nature and proceeds via a galvanic replacement mechanism in which the surface of CuTCNQ is replaced with metallic gold nanoparticles. Given the slight solubility of CuTCNQ in acetonitrile, two competing reactions, namely CuTCNQ dissolution and the redox reaction with KAuBr4, were found to operate in parallel. An increase in the surface coverage of CuTCNQ microrods with gold nanoparticles occurred with an increased KAuBr4 concentration in acetonitrile, which also inhibited CuTCNQ dissolution. The reaction progress with time was monitored using UV−visible, FT-IR, and Raman spectroscopy as well as XRD and EDX analysis, and SEM imaging. The CuTCNQ/Au nanocomposites were investigated for their photocatalytic properties, wherein the destruction of Congo red, an organic dye, by simulated solar light was found dependent on the surface coverage of gold nanoparticles on the CuTCNQ microrods. This method of decorating CuTCNQ may open the possibility of modifying this and other metal-TCNQ charge transfer complexes with a host of other metals which may have significant applications.

Effect of Imidazolium-based Ionic Liquids on the nanoscale morphology of CuTCNQ (TCNQ= 7, 7, 8, 8-tetracyanoquinodimethane) metal-organic semiconductors

We demonstrate for the first time the ionic-liquid-mediated synthesis of nanostructured CuTCNQ by the simple immersion of copper in a solution of TCNQ where the viscosity of the medium significantly impacts the corrosion–crystallization process and the final morphology of the material.

Assessment of traffic noise level before and after freeway widening using traffic microsimulation and a refined classic noise prediction method

In this paper, a refined classic noise prediction method based on the VISSIM and FHWA noise prediction model is formulated to analyze the sound level contributed by traffic on the Nanjing Lukou airport connecting freeway before and after widening. The aim of this research is to (i) assess the traffic noise impact on the Nanjing University of Aeronautics and Astronautics (NUAA) campus before and after freeway widening, (ii) compare the prediction results with field data to test the accuracy of this method, (iii) analyze the relationship between traffic characteristics and sound level. The results indicate that the mean difference between model predictions and field measurements is acceptable. The traffic composition impact study indicates that buses (including mid-sizedtrucks) and heavy goods vehicles contribute a significant proportion of total noise power despite their low traffic volume. In addition, speed analysis offers an explanation for the minor differences in noise level across time periods. Future work will aim at reducing model error, by focusing on noise barrier analysis using the FEM/BEM method and modifying the vehicle noise emission equation by conducting field experimentation.

In vitro assessment of surface congruency and integration of chondrocytes at adjacent edges of micro-fabricated clefts on cartilage

Osteochondral grafts are common treatment options for joint focal defects due to their excellent functionality. However, the difficulty is matching the topography of host and graft(s) surfaces flush to one another. Incongruence could lead to disintegration particularly when the gap reaches subchondoral region. The aim of this study is therefore to investigate cell response to gap geometry when forming cartilage-cartilage bridge at the interface. The question is what would be the characteristics of such a gap if the cells could bridge across to fuse the edges? To answer this, osteochondral plugs devoid of host cells were prepared through enzymatic decellularization and artificial clefts of different sizes were created on the cartilage surface using laser ablation. High density pellets of heterologous chondrocytes were seeded on the defects and cultured with chondrogenic differentiation media for 35 days. The results showed that the behavior of chondrocytes was a function of gap topography. Depending on the distance of the edges two types of responses were generated. Resident cells surrounding distant edges demonstrated superficial attachment to one side whereas clefts of 150 to 250 µm width experienced cell migration and anchorage across the interface. The infiltration of chondrocytes into the gaps provided extra space for their proliferation and laying matrix; as the result faster filling of the initial void space was observed. On the other hand, distant and fit edges created an incomplete healing response due to the limited ability of differentiated chondrocytes to migrate and incorporate within the interface. It seems that the initial condition of the defects and the curvature profile of the adjacent edges were the prime determinants of the quality of repair; however, further studies to reveal the underlying mechanisms of cells adapting to and modifying the new environment would be of particular interest.

Co-creating knowledge online : approaches for community artists

Forming peer alliances to share and build knowledge is an important aspect of community arts practice, and these co-creation processes are increasingly being mediated by the internet. This paper offers guidance for practitioners who are interested in better utilising the internet to connect, share, and make new knowledge. It argues that new approaches are required to foster the organising activities that underpin online co-creation, building from the premise that people have become increasingly networked as individuals rather than in groups (Rainie and Wellman 2012: 6), and that these new ways of connecting enable new modes of peer-to-peer production and exchange. This position advocates that practitioners move beyond situating the internet as a platform for dissemination and a tool for co-creating media, to embrace its knowledge collaboration potential. Drawing on a design experiment I developed to promote online knowledge co-creation, this paper suggests three development phases – developing connections, developing ideas, and developing agility – to ground six methods. They are: switching and routing, engaging in small trades of ideas with networked individuals; organising, co-ordinating networked individuals and their data; beta-release, offering ‘beta’ artifacts as knowledge trades; beta-testing, trialing and modifying other peoples ‘beta’ ideas; adapting, responding to technological disruption; and, reconfiguring, embracing opportunities offered by technological disruption. These approaches position knowledge co-creation as another capability of the community artist, along with co-creating art and media.

Pharmacist, general practitioner, and nurse perceptions, experiences, and knowledge of medication dosage form modification

Background: People often modify oral solid dosage forms when they experience difficulty swallowing them. Modifying dosage forms may cause adverse effects to the patient, and the person undertaking the modification. Pharmacists are often the first point of contact for people in the general community seeking advice regarding medications. Nurses are at the forefront of administering medications to patients and are likely to be most directly affected by a patient’s swallowing ability, while general practitioners (GPs) are expected to consider swallowing abilities when prescribing medications. Objective: To compare the perspectives and experiences of GPs, pharmacists, and nurses regarding medication dosage form modification and their knowledge of medication modification. Method: Questionnaires tailored to each profession were posted to 630 GPs, and links to an online version were distributed to 2,090 pharmacists and 505 nurses. Results: When compared to pharmacists and GPs, nurses perceived that a greater proportion of the general community modified solid dosage forms. Pharmacists and GPs were most likely to consider allergies and medical history when deciding whether to prescribe or dispense a medicine, while nurses’ priorities were allergies and swallowing problems when administering medications. While nurses were more likely to ask their patients about their ability to swallow medications, most health professionals reported that patients “rarely” or “never” volunteered information about swallowing difficulties. The majority of health professionals would advise a patient to crush or split noncoated non-sustained-release tablets, and would consult colleagues or reference sources for sustained-release or coated tablets. Health professionals appeared to rely heavily upon the suffix attached to medication names (which suggest modified release properties) to identify potential problems associated with modifying medications. Conclusion: The different professional roles and responsibilities of GPs, pharmacists, and nurses are associated with different perspectives of, and experiences with, people modifying medications in the general community and knowledge about consequences of medication modification.

Effects of scaffold architecture on mechanical characteristics and osteoblast response to static and perfusion bioreactor cultures

Tissue engineering focuses on the repair and regeneration of tissues through the use of biodegradable scaffold systems that structurally support regions of injury whilst recruiting and/or stimulating cell populations to rebuild the target tissue. Within bone tissue engineering, the effects of scaffold architecture on cellular response have not been conclusively characterized in a controlled-density environment. We present a theoretical and practical assessment of the effects of polycaprolactone (PCL) scaffold architectural modifications on mechanical and flow characteristics as well as MC3T3-E1 preosteoblast cellular response in an in vitro static plate and custom-designed perfusion bioreactor model. Four scaffold architectures were contrasted, which varied in inter-layer lay-down angle and offset between layers, whilst maintaining a structural porosity of 60 ± 5%. We established that as layer angle was decreased (90° vs. 60°) and offset was introduced (0 vs. 0.5 between layers), structural stiffness, yield stress, strength, pore size and permeability decreased, whilst computational fluid dynamics-modeled wall shear stress was increased. Most significant effects were noted with layer offset. Seeding efficiencies in static culture were also dramatically increased due to offset (~45% to ~86%), with static culture exhibiting a much higher seeding efficiency than perfusion culture. Scaffold architecture had minimal effect on cell response in static culture. However, architecture influenced osteogenic differentiation in perfusion culture, likely by modifying the microfluidic environment.

Numerical study of lid-driven square cavity with heat generation using LBM

In this study, the mixed convection heat transfer and fluid flow behaviors in a lid-driven square cavity filled with high Prandtl number fluid (Pr = 5400, ν = 1.2×10-4 m2/s) at low Reynolds number is studied using thermal Lattice Boltzmann method (TLBM) where ν is the viscosity of the fluid. The LBM has built up on the D2Q9 model and the single relaxation time method called the Lattice-BGK (Bhatnagar-Gross-Krook) model. The effects of the variations of non dimensional mixed convection parameter called Richardson number(Ri) with and without heat generating source on the thermal and flow behavior of the fluid inside the cavity are investigated. The results are presented as velocity and temperature profiles as well as stream function and temperature contours for Ri ranging from 0.1 to 5.0 with other controlling parameters that present in this study. It is found that LBM has good potential to simulate mixed convection heat transfer and fluid flow problem. Finally the simulation results have been compared with the previous numerical and experimental results and it is found to be in good agreement.

Estimation of biodiesel properties from chemical composition – An artificial neural network (ANN) approach

Biodiesel, produced from renewable feedstock represents a more sustainable source of energy and will therefore play a significant role in providing the energy requirements for transportation in the near future. Chemically, all biodiesels are fatty acid methyl esters (FAME), produced from raw vegetable oil and animal fat. However, clear differences in chemical structure are apparent from one feedstock to the next in terms of chain length, degree of unsaturation, number of double bonds and double bond configuration-which all determine the fuel properties of biodiesel. In this study, prediction models were developed to estimate kinematic viscosity of biodiesel using an Artificial Neural Network (ANN) modelling technique. While developing the model, 27 parameters based on chemical composition commonly found in biodiesel were used as the input variables and kinematic viscosity of biodiesel was used as output variable. Necessary data to develop and simulate the network were collected from more than 120 published peer reviewed papers. The Neural Networks Toolbox of MatLab R2012a software was used to train, validate and simulate the ANN model on a personal computer. The network architecture and learning algorithm were optimised following a trial and error method to obtain the best prediction of the kinematic viscosity. The predictive performance of the model was determined by calculating the coefficient of determination (R2), root mean squared (RMS) and maximum average error percentage (MAEP) between predicted and experimental results. This study found high predictive accuracy of the ANN in predicting fuel properties of biodiesel and has demonstrated the ability of the ANN model to find a meaningful relationship between biodiesel chemical composition and fuel properties. Therefore the model developed in this study can be a useful tool to accurately predict biodiesel fuel properties instead of undertaking costly and time consuming experimental tests.

A comparison study on hydrogen sensing performance of MoO3 nanoplatelets coated with a thin layer of Ta2O5 or La2O3

There has been significant interest in developing metal oxide films with high surface area-to-volume ratio nanostructures particularly in substantially increasing the performance of Pt/oxide/semiconductor Schottky-diode gas sensors. While retaining the surface morphology of these devices, they can be further improved by modifying their nanostructured surface with a thin metal oxide layer. In this work, we analyse and compare the electrical and hydrogen-sensing properties of MoO3 nanoplatelets coated with a 4 nm layer of tantalum oxide (Ta2O5) or lanthanum oxide (La2O3). We explain in our study, that the presence of numerous defect traps at the surface (and the bulk) of the thin high-� layer causes a substantial trapping of charge during hydrogen adsorption. As a result, the interface between the Pt electrode and the thin oxide layer becomes highly polarised. Measurement results also show that the nanoplatelets coated with Ta2O5 can enable the device to be more sensitive (a larger voltage shift under hydrogen exposure) than those coated with La2O3.

Mixed venous oxygen saturation monitoring revisited : thoughts for critical care nursing practice

Background Less invasive methods of determining cardiac output are now readily available. Using indicator dilution technique, for example has made it easier to continuously measure cardiac output because it uses the existing intra-arterial line. Therefore gone is the need for a pulmonary artery floatation catheter and with it the ability to measure left atrial and left ventricular work indices as well the ability to monitor and measure a mixed venous saturation (SvO2). Purpose The aim of this paper is to put forward the notion that SvO2 provides valuable information about oxygen consumption and venous reserve; important measures in the critically ill to ensure oxygen supply meets cellular demand. In an attempt to portray this, a simplified example of the septic patient is offered to highlight the changing pathophysiological sequelae of the inflammatory process and its importance for monitoring SvO2. Relevance to clinical practice SvO2 monitoring, it could be argued, provides the gold standard for assessing arterial and venous oxygen indices in the critically ill. For the bedside ICU nurse the plethora of information inherent in SvO2 monitoring could provide them with important data that will assist in averting potential problems with oxygen delivery and consumption. However, it has been suggested that central venous saturation (ScvO2) might be an attractive alternative to SvO2 because of its less invasiveness and ease of obtaining a sample for analysis. There are problems with this approach and these are to do with where the catheter tip is sited and the nature of the venous admixture at this site. Studies have shown that ScvO2 is less accurate than SvO2 and should not be used as a sole guiding variable for decision-making. These studies have demonstrated that there is an unacceptably wide range in variance between ScvO2 and SvO2 and this is dependent on the presenting disease, in some cases SvO2 will be significantly lower than ScvO2. Conclusion Whilst newer technologies have been developed to continuously measure cardiac output, SvO2 monitoring is still an important adjunct to clinical decision-making in the ICU. Given the information that it provides, seeking alternatives such as ScvO2 or blood samples obtained from femorally placed central venous lines, can unnecessarily lead to inappropriate treatment being given or withheld. Instead when using ScvO2, trending of this variable should provide clinical determinates that are useable for the bedside ICU nurse, remembering that in most conditions SvO2 will be approximately 16% lower.

Impinging jet simulation of stationary downburst flow over topography

A non-translating, long duration thunderstorm downburst has been simulated experimentally and numerically by modelling a spatially stationary steady flow impinging air jet. Velocity profiles were shown to compare well with an upper-bound of velocity measurements reported for full-scale microbursts. Velocity speed-up over a range of topographic features in simulated downburst flow was also tested with comparisons made to previous work in a similar flow, and also boundary layer wind tunnel experiments. It was found that the amplification measured above the crest of topographic features in simulated downburst flow was up to 35% less than that observed in boundary layer flow for all shapes tested. From the computational standpoint we conclude that the Shear Stress Transport (SST) model performs the best from amongst a range of eddy-viscosity and second moment closures tested for modelling the impinging jet flow.