Inorganics distribution in bio oils and char produced by biomass fast pyrolysis: The key role of aerosols

Fast pyrolysis of biomass is a promising process for the preparation of bio-oil dedicated to energy production. Inorganic species originally present in biomass are known to induce problems such as bio-oil instability or deposits and fouling. However the mechanisms of inorganic species release during biomass pyrolysis into the raw bio-oils still remain unclear. The present work focuses on the determination of inorganic distribution in the products from wheat straw and beech wood fast pyrolysis performed in a fluidized bed. More specifically, the bio-oils are fractionated by using a series of condensers. The results show that more than 60 wt.% of the inorganic content of the overall bio-oil is contained in the aerosols. Several possible interpretations for this observation are discussed. It is likely that the inorganics are transported within the aerosols droplets and solid particles which are recovered in the bio-oils, either by mechano-chemical processes, or by entrainment of submicron intermediate liquid compound formed in the first steps of biomass fast pyrolysis.     

Milli-free flow electrophoresis: I. Fast prototyping of mFFE devices

We coin a term of milli-free flow electrophoresis (mFFE) to describe mid-scale FFE with flow rates intermediate to macro-FFE and micro-FFE (μFFE). Introduced decades ago, mFFE did not find practical applications. We revive mFFE, as we view it as a viable purification complement to continuous synthesis in capillary reactors with product flow rates of ～5 to 2000 μL/min, too small for macro-FFE but too large for μFFE. The development of the tandem of continuous synthesis/purification will require the production and evaluation of a large number of prototypes of mFFE devices. As the first step, we developed a fast (<24 h) and economical (～$10) method for prototyping mFFE devices using a robotic milling machine. mFFE prototypes are constructed from two machined matching poly(methyl methacrylate) (PMMA) substrates, which are bonded in 10 min using dichloromethane to provide a strong and irreversible seal. Using the developed prototyping technology, we designed and evaluated 25 prototypes of mFFE devices. By optimizing the feed rates and rotational speeds of the drills, the depth of the electrode channels, the dimensions of the entrance and exit reservoirs, the sample flow rate, and the diameter and position of the sample input, we were able to achieve indefinitely long operation of the device with cycles of alternating 15-min electrophoresis and 0.5-min regeneration (bubble removal). The test analytes, rhodamine B and fluorescein, were baseline resolved by mFFE for flow rates ranging from 10 to 600 μL/min. These results prove that our prototyping approach is suitable for the challenging task of multi-parameter optimization of mFFE devices.     

Hölder estimates for singular non-local parabolic equations

In this paper, we establish local Hölder estimate for non-negative solutions of the singular equation (M.P) below, for m in the range of exponents . Since we have trouble in finding the local energy inequality of v directly, we use the fact that the operator σ(−Δ) can be thought as the normal derivative of some extension v^? of v to the upper half space (Caffarelli and Silvestre, 2007 [5]), i.e., v is regarded as boundary value of v^? the solution of some local extension problem. Therefore, the local Hölder estimate of v can be obtained by the same regularity of v^?. In addition, it enables us to describe the behavior of solution of non-local fast diffusion equation near their extinction time.     

Fast and simultaneous determination of phenolic compounds and caffeine in teas, mate, instant coffee, soft drink and energetic drink by high-performance liquid chromatography using a fused-core column

A fast HPLC method with diode-array absorbance detector and fluorescence detector for the analysis of 19 phenolic acids, flavan-3-ols, flavones, flavonols and caffeine in different types of samples was developed. Using a C₁₈ reverse-phase fused-core column separation of all compounds was achieved in less than 5 min with an overall sample-to-sample time of 10 min. Evaluation of chromatographic performance revealed excellent reproducibility, resolution, selectivity and peak symmetry. Limits of detection for all analyzed compounds ranged from 0.5 to 211 μg L⁻¹, while limits of quantitation ranged between 1.5 and 704 μg L⁻¹. The developed method was used for the determination of analytes present in different samples, including teas (black, white, green), mate, coffee, cola soft drink and an energetic drink. Concentration of the analyzed compounds occurring in the samples ranged from 0.4 to 314 mg L⁻¹. Caffeine was the analyte found in higher concentrations in all samples. Phytochemical profiles of the samples were consistent with those reported in the literature.     

Fast and efficient size-based separations of polymers using ultra-high-pressure liquid chromatography

Ultra-high-pressure liquid chromatography (UHPLC) has great potential for the separations of both small molecules and polymers. However, the implementation of UHPLC for the analysis of macromolecules invokes several problems. First, to provide information on the molecular-weight distribution of a polymer, size-exclusion (SEC) columns with specific pore sizes are needed. Development of packing materials with large pore diameters and pore volumes which are mechanically stable at ultra-high-pressures is a technological challenge. Additionally, narrow-bore columns are typically used in UHPLC to minimize the problem of heat dissipation. Such columns pose stringent requirements on the extra-column dispersion, especially for large (slowly diffusing) molecules. Finally, UHPLC conditions generate high shear rates, which may affect polymer chains. The possibilities and limitations of UHPLC for size-based separations of polymers are addressed in the present study. We demonstrate the feasibility of conducting efficient and very fast size-based separations of polymers using conventional and wide-bore (4.6 mm I.D.) UHPLC columns. The wider columns allow minimization of the extra-column contribution to the observed peak widths down to an insignificant level. Reliable SEC separations of polymers with molecular weights up to ca. 50 kDa are achieved within less than 1 min at pressures of about 66 MPa. Due to the small particles used in UHPLC it is possible to separate high-molecular-weight polymers (50 kDa ≤ M(r) ≤ 1-3 MDa, upper limit depends on the flow rate) in the hydrodynamic-chromatography (HDC) mode. Very fast and efficient HDC separations are presented. For very large polymer molecules (typically larger than several MDa, depending on the flow rate) two chromatographic peaks are observed. This is attributed to the onset of molecular deformation at high shear rates and the simultaneous actions of hydrodynamic and slalom chromatography.     

Developing counter current chromatography to meet the needs of pharmaceutical discovery

Experiments have been carried out to evaluate Counter Current Chromatography (CCC) as an alternative purification technique to preparative Reverse Phase High Performance Liquid Chromatography (RP-HPLC) for small molecule pharmaceuticals. The major drawback of CCC is the extensive time required in selecting the solvents to perform the separation. This is equivalent to choosing both the stationary phase and the mobile phase at the same time. In RP-HPLC it is a simple matter of deciding on the gradient, most samples can be purified on a C18 column with a water:acetonitrile gradient. The majority of the initial work was based on a standard test set of commercially available compounds, developed within our group to evaluate the performance of the HPLC apparatus and the column prior to the start of work each day. The work carried out on CCC has shown that the technique offers similar capabilities and can be carried out using similar protocols to RP-HPLC. CCC also has some advantages over RP-HPLC and can be regarded as a valuable addition to the chromatography toolbox.     

Using multiple short-end injections to develop fast electrophoretic separations--applications in iodide analysis

The aim of this study was to develop a fast CE separation method by using multiple short-end injections in a capillary coated with quaternary ammonium chitosan (HACC), in order to determine the iodide content of pharmaceutical formulations. The BGE was composed of 20 mM tris(hydroxymethyl)aminomethane and 11 mM hydrochloric acid, at pH 8. The internal standard used was thiocyanate. Separations were performed in a fused silica capillary (32 cm total length, 8.5 cm effective length and 50 μm i.d.) coated with HACC and direct UV detection at 220 nm. EOF was modified by flushing the capillary with polymeric solution, resulting in a semi-permanent coating of controlled and stable EOF. The EOF was anodic at pH 8. Different strategies, using single and multiple injection short-end configurations, were studied to develop a CE method that resulted in a maximum number of iodide samples analyzed per hour: one plug and flush (Sflush) 35 samples/h, one plug without flush (SWflush) 76 samples/h, four plugs and flush (Mflush) 61 samples/h, and four plugs without flush (MWflush) 80 samples/h. Using the multiple injection configuration, it was possible to inject up to four plugs using spacer electrolytes with good separation efficiency and selectivity. The voltage application time needed to separate the eight peaks (iodide and thiocyanate) with MWflush was only 12s. The method was validated and samples were analyzed using MWflush. Good linearity (R(2)>0.999); a limit of detection 0.4 mg L(-1); intermediate precision better than 3.8% (peak area) and recovery in the range of 99-102% were obtained.     

An efficient technique for recovering responses of parameterized structural dynamic problems

In this article,an effective technique is developed to efficiently obtain the output responses of parameterized structural dynamic problems.This technique is based on the conception of reduced basis method and the usage of linear interpolation principle.The original problem is projected onto the reduced basis space by linear interpolation projection,and subsequently an associated interpolation matrix is generated.To ensure the largest nonsingularity,the interpolation matrix needs to go through a timenode choosing process,which is developed by applying the angle of vector spaces.As a part of this technique,error estimation is recommended for achieving the computational error bound.To ensure the successful performance of this technique,the offline-online computational procedures are conducted in practical engineering.Two numerical examples demonstrate the accuracy and efficiency of the presented method.     

FFT-based convolution algorithm for fast and precise numerical evaluating diffracted field by photon sieve

FFT-based convolution is proposed to numerical solve Fresnel–Kirchhoff integral in Fresnel regime carefully and in a very shorter time in comparison to direct solving convolution. To show its capability, the algorithm was implemented to evaluate amplitude of a diffracted plane wave at the focal plane of photon sieves with different focal lengths. The calculated amplitudes are completely the same calculated via convolving operation but has advantageous of taking very very shorter time. The calculation was also repeated using single-FFT algorithm that produce same result for all ranges either below or upper the sampling criteria and different results in comparison to the other two methods.     

How much information do we need?

Modern technology is succeeding in delivering more information to people at ever faster rates. Under traditional views of rational decision making where individuals should evaluate and combine all available evidence, more information will yield better decisions. But our minds are designed to work in environments where information is often costly and difficult to obtain, leading us to use simple fast and frugal heuristics when making many decisions. These heuristics typically ignore most of the available information and rely on only a few important cues. Yet they make choices that are accurate in their appropriate application domains, achieving ecological rationality through their fit to particular information structures. This paper presents four classes of simple heuristics that use limited information—recognition-based heuristics, one-reason decision mechanisms, multiple-cue elimination strategies, and quick sequential search mechanisms—applied to environments from stock market investment to judging intentions of other organisms to choosing a mate. The findings that ecological rationality can be achieved with limited information are also used to indicate how our mind’s design, relying on decision mechanisms tuned to specific environments, should be taken into account in our technology’s design, creating environments that can enable better decisions.