Deflagration-to-detonation transition process for spherical aluminum dust/epoxypropane mist/air mixtures in a large-scale experimental tube

The deflagration-to-detonation transitions (DDTs) for clouds of spherical aluminum dust (SAD) mixed with air or epoxypropane mist (EPM) and air were investigated in a 29.6-m-long experimental tube of 199 mm in diameter. The clouds formed through the injection of SAD and SAD/liquid epoxypropane samples into the experimental tube. Explosions of the SAD/air mixture were initiated using a 7-m-long EPM/air cloud explosion ignited by a 40-J electric spark. Explosions in SAD/EPM/air clouds were initiated using a 1...     

Pattern dynamics in cellular perception

By using a giant amoeboid cell of the Physarum plasmodium, changes in the intracellular distribution of chemical components are studied in relation to information processing in cell behavior. Various kinds of metabolites oscillate, and so the protoplasm should be a collection of chemical oscillators. Spatially, characteristic chemical patterns are self-organized for different cell shapes, and hence cell behavior. New phase waves propagate throughout the cell upon local stimulation, their direction being opposite for attraction and repulsion. Locomotion is inhibited when the coherence of the oscillators breaks. Thus, pattern dynamics is correlated with information processing in the amoeboid cell.     

Metabolite identification of the antimalarial piperaquine in vivo using liquid chromatography–high‐resolution mass spectrometry in combination with multiple data‐mining tools in tandem

Artemisinin‐based combination therapy is widely used for the treatment of uncomplicated Plasmodium falciparum malaria, and piperaquine (PQ) is one of important partner drugs. The pharmacokinetics of PQ is characterized by a low clearance and a large volume of distribution; however, metabolism of PQ has not been thoroughly investigated. In this work, the metabolite profiling of PQ in human and rat was studied using liquid chromatography tandem high‐resolution LTQ‐Orbitrap mass spectrometry (HRMS). The biological samples were pretreated by solid‐phase extraction. Data processes were carried out using multiple data‐mining techniques in tandem, i.e., isotope pattern filter followed by mass defect filter. A total of six metabolites (M1–M6) were identified for PQ in human (plasma and urine) and rat (plasma, urine and bile). Three reported metabolites were also found in this study, which included N‐oxidation (M1, M2) and carboxylic products (M3). The subsequent N‐oxidation of M3 resulted in a new metabolite M4 detected in urine and bile samples. A new metabolic pathway N‐dealkylation was found for PQ in human and rat, leading to two new metabolites (M5 and M6). This study demonstrated that LC‐HRMSⁿ in combination with multiple data‐mining techniques in tandem can be a valuable analytical strategy for rapid metabolite profiling of drugs. Copyright © 2016 John Wiley & Sons, Ltd.     

受限空间油气爆燃火焰形态

通过受限空间油气爆燃可视化实验发现，在不同初始油气体积分数下，爆燃火焰呈现出不同的表观特征，据此提出了受限空间油气爆燃的3种火焰形态，即光滑球形火焰、褶皱球形火焰和卷曲絮状火焰。分析了3种火焰形态的形成机理，并通过实验观测与理论分析，给出了区分3种火焰形态的临界条件。结合实验中采集到的关键参数，总结了不同的火焰形态下受限空间油气爆燃的反应产物、最大压力、升压速率、反应时间、火焰强度等关键参数的特征与变化规律。     

Deposition pattern of drying droplets

The drying of liquid droplets is a common daily life phenomenon that has long held a special interest in scientific research. When the droplet includes nonvolatile solutes, the evaporation of the solvent induces rich deposition patterns of solutes on the substrate. Understanding the formation mechanism of these patterns has important ramifications for technical applications,ranging from coating to inkjet printing to disease detection. This topical review addresses the development of physical understanding of tailoring the specific ring-like deposition patterns of drying droplets. We start with a brief introduction of the experimental techniques that are developed to control these patterns of sessile droplets. We then summarize the development of the corresponding theory. Particular attention herein is focused on advances and issues related to applying the Onsager variational principle (OVP) theory to the study of the deposition patterns of drying droplets. The main obstacle to conventional theory is the requirement of complex numerical solutions, but fortunately there has been recent groundbreaking progress due to the OVP theory. The advantage of the OVP theory is that it can be used as an approximation tool to reduce the high-order conventional hydrodynamic equations to first-order evolution equations,facilitating the analysis of soft matter dynamic problems. As such, OVP theory is now well poised to become a theory of choice for predicting deposition patterns of drying droplets.     

Multidimensional space groups: Tables and standards

The previous speakers have dealt with tangible physical objects; I am to deal with organizational and symbolic problems. The symbolic problems are of greater scientific importance, but I must begin with those of human organization and in particular with the structure of the International Union of Crystallography (acronym IUCr).     

Phase retrieval from fringe pattern with 1-D discrete wavelet transform

This paper proposes a novel method to obtain frequency modulation (FM) signals from a single fringe pattern for phase retrieval. First, a 1D discrete Meyer wavelet is employed to decompose the pattern image signal row by row and the soft-thresholding approach is applied to remove noise. The low frequency coefficients of the wavelet decomposition are then set to 0, and the signal is reconstructed. Moreover, the optimal wavelet decomposition level is adaptively determined using a cost function-based method. The reconstructed signal, which no longer contains a background component, is normalized using a nonlinear and piecewise normalization method. The proposed method is faster and more accurate than some other phase retrieval approaches, which is illustrated with two test cases.     

Free convection of a dusty‐gas flow along a semi‐infinite vertical cylinder

An analysis is performed to study the free convection of a dusty‐gas flow along a semi‐infinite isothermal vertical cylinder. The governing equations of the flow problem are transformed into non‐dimensional form and the resulting nonlinear, coupled parabolic partial differential equations have been solved numerically using an implicit finite difference scheme of Crank–Nicholson type. The flow variables such as gas–velocity, dust‐particle velocity and temperature, shearing stress and heat transfer coefficients are calculated numerically for various parameters occurring in the problem. It is observed that due to the presence of dust particles, the gas velocity is found to decrease. Copyright © 2009 John Wiley & Sons, Ltd.     

Gaussian pre-filtering for uncertainty minimization in digital image correlation using numerically-designed speckle patterns

This paper discusses the effect of pre-processing image blurring on the uncertainty of two-dimensional digital image correlation (DIC) measurements for the specific case of numerically-designed speckle patterns having particles with well-defined and consistent shape, size and spacing. Such patterns are more suitable for large measurement surfaces on large-scale specimens than traditional spray-painted random patterns without well-defined particles. The methodology consists of numerical simulations where Gaussian digital filters with varying standard deviation are applied to a reference speckle pattern. To simplify the pattern application process for large areas and increase contrast to reduce measurement uncertainty, the speckle shape, mean size and on-center spacing were selected to be representative of numerically-designed patterns that can be applied on large surfaces through different techniques (e.g., spray-painting through stencils). Such “designer patterns” are characterized by well-defined regions of non-zero frequency content and non-zero peaks, and are fundamentally different from typical spray-painted patterns whose frequency content exhibits near-zero peaks. The effect of blurring filters is examined for constant, linear, quadratic and cubic displacement fields. Maximum strains between ±250 and ±20,000 µε are simulated, thus covering a relevant range for structural materials subjected to service and ultimate stresses. The robustness of the simulation procedure is verified experimentally using a physical speckle pattern subjected to constant displacements. The stability of the relation between standard deviation of the Gaussian filter and measurement uncertainty is assessed for linear displacement fields at varying image noise levels, subset size, and frequency content of the speckle pattern. It is shown that bias error as well as measurement uncertainty are minimized through Gaussian pre-filtering. This finding does not apply to typical spray-painted patterns without well-defined particles, for which image blurring is only beneficial in reducing bias errors.     

Biochemical study for the effect of henna (Lawsonia inermis) on Escherichia coli

Leaf samples of Lawsonia inermis (Li) were examined for their antimicrobial potential. Broth extracts in different concentrations were prepared and bioassayed in vitro for the growth of Escherichia coli. The growth of E. coli pathogen was inhibited to various degrees by increasing the concentration of the herbal powder. In addition to the observed alterations which were detected electrophoretically in the protein pattern, were activities of the amylase enzyme and glycoprotein fractions. The protein pattern has one common band of Rf 0.47 and two characteristic bands of Rf 0.36 and Rf 0.42 for E. coli sample. The quantitative mutation was observed in the bacteria with different concentrations of L. inermis compared with the control. Some types of proteins in E. coli completely disappeared upon being S.I affected. The amylase pattern showed one common band with Rf 0.037 and two characteristic bands with Rf 0.18 and Rf 0.37 for E. coli sample. The obvious quantitative mutation observed in bacteria with different concentrations of L. inermis compared with E. coli. The glycoprotein pattern recorded one common band at R₁ with Rf 0.94 for E. coli sample and bacteria inoculated with different concentrations of L. inermis. These results confirmed the antibacterial activity of henna leaves and supported the traditional use of the plant in therapy of bacterial infections and disturbances that occurred at the biochemical level. The broth extract of the L. inermis leaves showed obvious antibacterial activity against E. coli.