Thermal destruction kinetics of Bacillus licheniformis spores in carrot juice extract as influenced by pH,type of acidifying agent and heating method

The combined effects of different heating methods (conventional (CH) vs. Ohmic (OH)), types of acidifying agent (citric vs malic acid) and pH levels (pH 4.5, 5.5 and 6.2) were investigated to study their influence on destruction kinetics of spores of Bacillus licheniformis. The ultimate aim to generate relevant kinetic data on an indicator microbial spore is useful for assessing the efficacy of thermal processes for acid or acidified low acid foods. Kinetic parameters were evaluated according to the first-order kinetic model. Temperature and pH showed a highly significant (p < 0.01) effect on the spore destruction kinetics. Ohmic heating showed marginally better rate of bacterial destruction than conventional heating. The overall range of D and z values were 1.1–11.2 min and 12.6–17 °C, respectively, depending up on the pH and temperature levels, method of heating as well as the type of acidulate used. The shortest D_97°C = 1.1 min was obtained at pH of 4.5 when citric acid was used as an acidifying agent in OH. No significant difference (p > 0.05) was observed with respect to D and z values between the two types of acidifying agents.     

Correlation between central receiver size and solar field using flat heliostats

In Central Receiver Systems (CRSs), thousands of heliostats track the sunrays and reflect beam radiation on to a receiver surface. The size of the reflected image and the extent of reflection from the heliostats are one of the important criteria that need to be taken into account while designing a receiver, since spillage losses may vary from 2 to 16% of the total losses. The present study aims to determine the size of an external cylindrical receiver, such that the rays reflected from all the heliostats in the field are intercepted. A dimensionless correlation with respect to tower height and receiver size (diameter and height) as a function of heliostat size and its position is discussed in the paper. This correlation could be used as a first-order approximation to estimate the receiver dimensions. When applied to the Ivanpah Solar Electricity Generating Station (ISEGS) plant, the correlation yields satisfactory estimation of receiver dimensions.     

Effect of shear deformation on interfacial stresses in plated beams subjected to arbitrary loading

Bonding a fibre reinforced polymer (FRP) composite or metallic plate to the soffit of a reinforced concrete (RC), timber or metallic beam can significantly increase its strength and other aspects of structural performance. These hybrid beams are often found to fail due to premature debonding of the plate from the original beam in a brittle manner. This has led to the development of many analytical solutions over the last two decades to quantify the interfacial shear and normal stresses between the adherends. The adherends are subjected to axial, bending and shear deformations. However, most analytical solutions have neglected the influence of shear deformation of the adherends. For the few solutions which consider this effect in an approximate manner, their applicability is limited to one or two specific load cases. This paper presents a general analytical solution for the interfacial stresses in plated beams under an arbitrary loading with the shear deformation of the adherends duly considered. The shear stress distribution is assumed to be parabolic through the depth of the adherends in predicting the interfacial shear stress and Timoshenko's beam theory is adopted in predicting interfacial normal stress to account for the shear deformation. The solution is applicable to a beam of arbitrary prismatic cross-section bonded symmetrically or asymmetrically with a thin or thick plate, both having linear elastic material properties. The effect of shear deformation is illustrated through an example beam. The influence of material and geometric parameters of the adherends and adhesive on the interfacial stress concentrations at the plate end is discussed.     

Optimization of Lithium Content and Sintering Aid for Maximized Li+ Conductivity and Density in Ta‐Doped Li7La3Zr2O12

Ta‐doped cubic phase Li₇La₃Zr₂O₁₂ (LLZ) lithium garnet received considerable attention in recent times as prospective electrolyte for all‐solid‐state lithium battery. Although the conductivity has been improved by stabilizing the cubic phase with the Ta⁵⁺ doping for Zr⁴⁺ in LLZ, the density of the pellet was found to be relatively poor with large amount of pores. In addition to the high Li⁺ conductivity, density is also an essential parameter for the successful application of LLZ as solid electrolyte membrane in all‐solid‐state lithium battery. Systematic investigations carried out through this work indicated that the optimal Li concentration of 6.4 (i.e., Li_6.4La₃Zr_1.4Ta_0.6O₁₂) is required to obtain phase pure, relatively dense and high Li⁺ conductive cubic phase in Li_7?xLa₃Zr_2?xTa_xO₁₂ solid solutions. Effort has been also made in this work to enhance the density and Li⁺ conductivity of Li_6.4La₃Zr_1.4Ta_0.6O₁₂ further through the Li₄SiO₄ addition. A maximized room‐temperature (33°C) total (bulk + grain boundary) Li⁺ conductivity of 3.7 × 10^?4 S/cm and maximized relative density of 94% was observed for Li_6.4La₃Zr_1.4Ta_0.6O₁₂ added with 1 wt% of Li₄SiO₄.     

Measurement and targeting of thermophysical properties of carrot and meat based alginate particles for thermal processing applications

The objective of the study was to investigate the thermo-physical properties of meat and carrot based alginate particles as influenced by the formulation variables. A response surface methodology (RSM) was used to study the effect of sodium alginate concentration, calcium chloride concentration and dipping time in the calcium chloride solution, at five levels each, on the thermo-physical properties of the fabricated particles (9 mm in diameter and 9 mm in height). Density was similar for all conditions. Increasing sodium alginate concentration resulted in a significant decrease in the heat capacity and thermal conductivity values. These changes were primarily attributed to the lowering of moisture content of the particles resulting from the treatment. Using RSM, optimum conditions for fabricating particles having similar thermo-physical properties to real foods were obtained as 5.3% and 4.9% sodium alginate, 2.2% calcium chloride and 14.2 and 36.0 h immersion in the calcium chloride solution for meat and carrot alginate particles, respectively.     

Object-oriented methodology for intersection simulation model under heterogeneous traffic conditions

In developing countries like India, the traffic on roads is highly heterogeneous in nature, with vehicles of widely varying static and dynamic characteristics. In this type of traffic, vehicles do not follow lane discipline and they move freely over the entire width of roadway based on availability of space. To study this type of complex traffic flow and associated vehicular interactions, simulation is considered as an effective tool. An object-oriented methodology (OOM) for heterogeneous traffic simulation is proposed in this paper with focus on mid-block and intersection flow modeling. The paper presents the basics and advanced features of object-oriented programming (OOP) in detail in the context of traffic flow. The sample C++ code is discussed in detail to demonstrate the implementation of OOP features, such as encapsulation, inheritance and polymorphism. The contribution of this research work is the development of software objects for various components such as vehicle, traffic, link and node. This software can be adopted for heterogeneous traffic simulation programs, in general.     

Microscopic initiation mechanisms in energetic material crystals

Abstract

The sensitivity to initiation of different crystalline polymorphic forms of the same energetic material is known to differ. Similarly single crystals of energetic materials such as PETN and nitromethane show a shock initiation sensitivity anisotropy. The crystal structure of the energetic materials is thus known to control the initiation sensitivity of the same. As will be described in this paper there is evidence to indicate that the orientation of the molecules surrounding a given molecule in the crystal lattice, influences the initial decomposition reaction of the molecule. Several microscopic mechanisms of initiation have been postulated. It is shown here that added to and above these mechanisms the crystal structure can be taken into account in a metastable intermolecular trigger reaction which explains the observed differences in initiation as a function of crystal structure.     

Carotenoproteins from lobster waste as a potential feed supplement for cultured salmonids

Lobster waste (including the head and hard carapace, viscera, mandibles and gills) contains approximately 54 μg/g total astaxanthin, 29% protein, 23% chitin, 34% ash and 2.2% crude fat on a dry weight basis. Trypsin from bovine pancreas was applied to facilitate the recovery of carotenoid pigments and protein as carotenoprotein complex, which was subsequently air‐dried to a stable powder form at 45°C and 15% relative humidity. The product obtained was found to contain 60% protein, 15% crude fat, 6% ash, 8% chitin and 295 μg/g total astaxanthin. Thus, the process achieved a substantial reduction in the levels of anti‐nutrients associated with lobster waste (i.e., ash and chitin) while elevating the levels of carotenoid pigments and essential nutrients such as protein and fat in the recovered product These characteristics of the final product suggest that it could be used as an inexpensive source of pigment and protein in diets of cultured salmonid species.     

EFFECT OF TEMPERATURE GRADIENT ON MOISTURE MIGRATION DURING MICROWAVE HEATING

ABSTRACT

The effect of temperature gradient on moisture migration during microwave heating of food materials was analyzed in this study. The analysis was performed using the finite element model developed and validated previously (Zhou et al., 1994b). Potato and bread were used as test materials. For high density food material (potato), temperature gradient effect on moisture migration was found to be negligible (less than 5%). For low density and porous food material (bread), percentage contribution of moisture movement due to temperature gradient was high (114%). However, the absolute difference of moisture content with and without considering temperature gradient effect was small for the microwave process studied, i.e., one-minute of microwave heating followed by three-minute of holding time period.     

Conflict detection during plan integration for multi-agent systems

This paper describes techniques developed for conflict detection during plan integration. Agents' intensions are represented with intended goal structure (IGS) and the E-PERT diagrams. Conflicts are classified as goal, plan, and belief conflicts. Before integrating individual plans and detecting plan conflicts, agents first detect and eliminate their goal conflicts by exchanging their IGS. Plan integration is done through merging individual E-PERT diagrams. Project estimation and review technique (PERT) diagrams have been used extensively in the systems analysis area since the 1980s to provide a global consistent view of parallel activities within a project. We extended the PERT diagrams for use in the plan integration activity within multi-agent systems (MAS). The E-PERT diagram contributes to maintain traceable temporal relations among agents' local scheduled actions. Combined with pattern matching, plan conflicts due to resource sharing, or conflicting conditions (i.e., postconditions of one action disabling preconditions of another action) can be detected. The conflict detection techniques are implemented in a sensible agent testbed to promote deployment and performance analysis.