Enzyme‐Based Nanoscale Composites for Use as Active Decontamination Surfaces

Perhydrolase S54V (AcT) effectively catalyzes the perhydrolysis of propylene glycol diacetate (PGD) to generate peracetic acid (PAA). PAA is a potent oxidant used for sanitization and disinfection, with broad effectiveness against bacteria, yeasts, fungi, and spores. In this study, active and stable composites are developed by incorporating AcT–carbon nanotube conjugates into polymer and latex‐based paint. At a conjugate loading of 0.16% (w/v), the composite generated 11 mM PAA in 20 min, capable of killing more than 99% spores initially charged at 10⁶ colony‐forming units per milliliter.     

Sand Replacement Method for Determination of Shrinkage Limit of Fine-Grained Soils

Mercury is one of the many hazardous substances that has been recognized and banned by many natural codes of practice and governments. Because many laboratory works in research and practice require the use of mercury, safe alternative materials and procedures are being researched. One of the Atterberg limits dealing with volume stability of soils in the field is the shrinkage limit. The conventional method followed by many national codes of practice involves the use of mercury to measure the volume of dry soil pat. This paper proposes sand replacement method to determine the shrinkage limit of soils in the laboratory. This method uses sand of uniform gradation to determine the volume of dry soil pat. The proposed method is simple, safe, free from the limitations of the conventional mercury and wax methods, and eco-friendly. The shrinkage limit values obtained from the proposed sand replacement method compare very well with those from the mercury displacement method.     

A hybrid algorithm for a class of vehicle routing problems

In this work we propose a hybrid algorithm for a class of Vehicle Routing Problems with homogeneous fleet. A sequence of Set Partitioning (SP) models, with columns corresponding to routes found by a metaheuristic approach, are solved, not necessarily to optimality, using a Mixed Integer Programming (MIP) solver, that may interact with the metaheuristic during its execution. Moreover, we developed a reactive mechanism that dynamically controls the dimension of the SP models when dealing with large size instances. The algorithm was extensively tested on benchmark instances of the following Vechicle Routing Problem (VRP) variants: (i) Capacitated VRP; (ii) Asymmetric VRP; (iii) Open VRP; (iv) VRP with Simultaneous Pickup and Delivery; (v) VRP with Mixed Pickup and Delivery; (vi) Multi-depot VRP; (vii) Multi-depot VRP with Mixed Pickup and Delivery. The results obtained were quite competitive with those found by heuristics devoted to specific variants. A number of new best solutions were obtained.     

The biocompatibility of sulfobetaine engineered polymethylmethacrylate by surface entrapment technique

Sulfobetaine-modified polymethylmethacrylate (PMMA) systems were created by physically entrapping the zwitterionic species on the PMMA surface. The presence of the sulfobetaine molecules on these surfaces were verified by ATR–FTIR and SEM–EDAX analysis, while wettability of the films was investigated by dynamic contact angle measurements. The short-term (4 h) adhesion of two bacterial species (gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa) on these surfaces were studied. Mouse RAW 264.7 macrophage cells were used to assess the cell adhesion and inflammatory response by quantifying the expression levels of proinflammatory cytokines namely TNFα and IL1β by measuring their mRNA profiles in the cells using real-time polymerase chain reaction (RT-PCR) normalized to the house keeping gene GAPDH. Whilst mouse L-929 fibroblast cells were used to assess the propensity for the materials to support fibroblast cell adhesion. A decrease in the adhesion of S. aureus by 63% and P. aeruginosa by 49% was observed on sulfobetaine modified PMMA films after 4 h. In all the cases, sulfobetaine modified PMMA films reduced cellular adhesion events (*P < 0.05) with respect to the base materials, which could be linked to the reduced protein adsorption observed on these surfaces. The cellular inflammatory response was suppressed on sulfobetaine modified substrates as expression levels of pro-inflammatory cytokines (TNFα and IL1β) was found to be up regulated on bare PMMA, while it was significantly lower on sulfobetaine modified PMMA (**P < 0.001). Thus the sulfobetaine entrapment process can be applied on polymethylmethacrylate in order to achieve low biointeractions and reduced inflammatory host responses for various biomedical and biotechnological applications.     

Development and Performance Evaluation of Interlocking-Block Masonry

Accelerated mortarless masonry constructions have been developed or are being used in different countries with limited research studies. This paper discusses first the salient features of interlocking-block masonry and then the development of simple interlocking-concrete-block masonry systems, keeping in view the requirements of shape simplicity and ease of manufacture. Testing of wallettes under axial compression, eccentric compression (e∕t ratios of 0, t/6, and t/3), and flexural loading parallel and perpendicular to bed joints were carried out on dry-stacked specimens. Interlocking-block masonry results in relatively high efficiency factors in axial compression and eccentric-to-axial capacity ratio when compared with mortar bedded masonry. Unlike conventional masonry, the flexural capacity of interlocking-block masonry normal to the bed joint is higher than that parallel to the bed joint. A better interlocking mechanism of channel-shaped interlocking blocks, as compared to I-shaped blocks, leads to a relatively higher flexural capacity of the former.     

Analysis of thermodynamic scope engine simulation model empirical coefficients: Suitability assessment and tuning of conventional hydrocarbon fuel coefficients for bio syngas

The sensitivity of empirical correlations and coefficients of thermodynamic quasi and zero dimensional SI engine models to mixture thermo-chemistry and engine thermo-kinematic response variations is addressed. Mixture thermo-chemistry alterations, as in case engine operation with non-regular alternatives, and accompanying in-cylinder fluid flow and combustion dynamics perturbations induce variations in full cycle thermodynamic and process thermo-kinematic response with potential influence on empirical coefficients. As an example, producer gas and natural gas thermo-physical properties differ significantly, extending to thermo-kinematic response over a range of operating conditions. Literature indicates monotonous adoptions of conventional fuel coefficients for simulation studies with non-regular fuels and tuning efforts are directed at initial and boundary conditions, which are many times thermodynamically untenable. The current work evaluates the suitability of empirical correlations and coefficients tuned for conventional hydrocarbon fuels, for numerical simulation of producer gas fuelled operation. Producer gas specific coefficients are evolved, following a generic approach, wherever necessary.Assessment of producer gas thermo-physical properties indicates four times higher thermal conductivity of producer gas (40.0 mW/mK) compared to gasoline (11.2 mW/mK), attributed to the presence of hydrogen. The influence is on convective cooling which is reflected in about 32% cooling load as against 25% for spark ignited engines. In response, the Reynolds number power coefficient of convective heat transfer correlation nearly doubles from 0.35 to 0.76. Analysing laminar flame speed coefficients, the inability of CHEMKIN-III to accurately predict laminar flame speed of hydrogen containing gases requiring adoption of CHEMKIN-II is a key observation. Substantial deviations are also observed for apparent heat release profiles with extended terminal stage combustion duration for producer gas, attributed to enhanced convective cooling. Curve fit analysis evolves producer gas specific shape and efficiency coefficients of 0.71 and 2.23 as against 2.0 and 5.0 for conventional fuels. The terminal combustion duration also changes from 1.22 to 2.12 ms. Using tuned coefficients permits near concurrent evolution of simulation and experimental pressure and heat release profiles establishing the need for fuel specific coefficients.     

Structural,Electrical and Magnetic Behaviour of FeTe0.5Se0.5 Superconductor

We report the synthesis as well as structural and physical properties of the bulk polycrystalline FeTe and FeTe_0.5Se_0.5 compounds. These samples are synthesised by the solid state-reaction method via vacuum encapsulation. Both studied compounds are crystallized in a tetragonal phase with space group P4/nmm. The parent FeTe compound shows an anomaly in resistivity measurement at around 78 K, which is due to the structural change along with a magnetic phase transition. The superconductivity in the FeTe_0.5Se_0.5 sample at 13 K is confirmed by the resistivity measurements. DC magnetisation along with an isothermal (M–H) loop shows that FeTe_0.5Se_0.5 possesses bulk superconductivity. The upper critical field is estimated through resistivity ρ (T,H) measurements using Gingzburg–Landau (GL) theory and is above 50 T with 50 % resistivity drop criterion. The origin of the resistive transition broadening under magnetic field is investigated by thermally activated flux flow. The magnetic field dependence of the activation energy of the flux motion is discussed.     

A Bayesian Joint Mixture Framework for the Integration of Anatomical Information in Functional Image Reconstruction

We present a Bayesian joint mixture framework for integrating anatomical image intensity and region segmentation information into emission tomographic reconstruction in medical imaging. The joint mixture framework is particularly well suited for this problem and allows us to integrate additional available information such as anatomical region segmentation information into the Bayesian model. Since this information is independently available as opposed to being estimated, it acts as a good constraint on the joint mixture model. After specifying the joint mixture model, we combine it with the standard emission tomographic likelihood. The Bayesian posterior is a combination of this likelihood and the joint mixture prior. Since well known EM algorithms separately exist for both the emission tomography (ET) likelihood and the joint mixture prior, we have designed a novel EM² algorithm that comprises two EM algorithms—one for the likelihood and one for the prior. Despite being dove-tailed in this manner, the resulting EM² algorithm is an alternating descent algorithm that is guaranteed to converge to a local minimum of the negative log Bayesian posterior. Results are shown on synthetic images with bias/variance plots used to gauge performance. The EM² algorithm resulting from the joint mixture framework has the best bias/variance performance when compared with six other closely related algorithms that incorporate anatomical information to varying degrees.