A real-time approach for automatic defect detection from PCBs based on SURF features and morphological operations

Multimedia Tools and Applications - This paper presents an automatic inspection approach for Printed Circuit Boards (PCBs) with accurate determination of the fault location and identification of...     

High-pressure steam curing of high-slag cement. II. Strength of cement-sand mixes

The strength of dense high-slag cement-sand mixes autoclaved at 180 lbf/in², and of certain aerated mixes autoclaved at pressures ranging from 120 to 210 lbf/in², has been determined. It was found that maximum strengths were developed in an autoclaving period of 5 h at 180 lbf/in², and that longer periods, as well as higher autoclaving pressures, yielded lower strengths. The maximum strength values obtained for compacted 1: 3 (w/w) mixes were 425 kg/cm² in the absence of fine quartz, and 510 kg/cm² in the presence of suitable addition of fine quartz. The corresponding values for Portland cement mixes were, respectively, 330 and 460 kg/cm² for a heating period of 5 h, and 360 and 505 kg/cm² for a period of 6 h.     

The potential use of alkaline protease from Streptomyces albidoflavus as an eco-friendly wool modifier

The main task of this study is to search for the proper conditions of the enzymatic treatment using an alkaline bacterial protease, as an eco-friendly option, to improve some performance properties and dyeability of grey wool fabric with acid dyes. The efficiency of the enzymatic treatment has been improved by prewashing in the presence of a nonionic wetting agent alone and in combination with H₂O₂. The enhancement in wool performance properties as well as in the extent of post-acid dyeing is determined by pretreatment regime, enzyme dosage, as well as enzymatic treatment conditions. For modified wool fabric samples, as the weight loss increases, the nitrogen content decreases, the whiteness index as well as the dyeability with the acid dye improves compared with the prewashed fabric samples. Proper conditions for maximising the efficiency of enzymatic treatment along with attaining better performance properties and minimal wool damage are: prewashing in the presence of a nonionic surfactant along with H₂O₂ followed by enzymatic treatment using the enzyme dosage (3?ml/g fabric), pH (9), incubation time (45?min), temperature (40?°C), LR (1/20) and rotational speed (40?rpm). The enzyme inactivation was performed at 100?°C for 5?min, followed by thoroughly rinsing, neutralising and air-drying before testing. SEM images also provide evidence that pretreatment of the wool substrate enhanced the proteolysis of cuticle layers, their degradation and potential removal by the subsequent protease treatment.     

Study of the rate of liquid–solid mass transfer controlled processes in helical tubes under turbulent flow conditions

The liquid–solid mass transfer behaviour of helical tubes was studied by the diffusion controlled dissolution of copper tubes in acidified dichromate. Variables studied were solution velocity, tube diameter, coil diameter and physical properties of the solution. The effect of drag reducing polymers on the rate of mass transfer in the helical tubes was also studied. The blank solution mass transfer data were correlated for the conditions 850 < Sc < 1322; 6000 < Re < 23,400 and 5 < d_c/d < 25 by the equation.

Sh=0.107Sc0.33Re0.68$Sh=0.107S{c}^{0.33}R{e}^{0.68}$

Safeguarded use of the implicit restarted lanczos technique for solving non-linear structural eigensystems

This paper presents a new algorithm for evaluating the eigenvalues and their corresponding eigenvectors for large-scale non-linear eigensystems in structural dynamics. The algorithm is based on solving a sequence of algebraic eigenproblems and updating the parameter λ. The implicitly restarted Lanczos method had been determined to be well suited for solving the linear eigenproblems that arise in this context. A zero-finder approach that uses rational interpolation to approximate the generalized eigenvalues has been developed to update λ. The methodology of the new algorithm developed here is designed to evaluate a subset of the parametrized non-linear eigencurves at specific values of λ. Numerical experiments show that the new eigensolution technique is superior to existing approaches for large-scale problems and competitive for small-size problems. The main emphasis of this contribution is the derivation and analysis of this scheme for non-linear structural eigensystems.     

Low-endurance fatigue of an aluminium alloy and a stainless steel in plane bending at ambient and elevated temperatures

Flat uniform specimens were cyclically bent over formers. At room temperature two strain ratios were used, R = −1 and 0, i.e. reversed symmetrical and asymmetrical strains, respectively, the strain ratio being defined as the ratio of the minimum to the maximum strain in a cycle. The increase in the value of the strain ratio was found to decrease the fatigue life of the aluminium alloy and to increase it for the stainless steel. For room temperature tests and at R = −1, the bending moment at maximum strain was found to increase in the early part of the test and was then followed by a decrease until fracture occurred, whilst for R = 0 a continuous decrease occurred throughout the tests. The effect of test temperature on fatigue life was found to be considerable and throughout the tests at elevated temperature the cyclic bending moment decreased.     

A green approach for modification and functionalization of wool fabric using bio- and nano-technologies

In the present work, we propose a green and sustainable strategy for eco-friendly surface modification of wool structure using biosynthesized kerationlytic proteases, from C4-ITA-EGY, Streptomyces harbinensis S11-ITA-EGY and Streptomyces carpaticus S33-ITA-EGY, followed by subsequent environmentally sound functionalization of the bio-treated substrates using ZnONPs, ZrO₂NPs, ascorbic acid and vanillin, individually, to provide durable antibacterial as well as UV-protection properties. Both surface modification changes and the extent of functionalization of the final products were characterized by SEM, EDX, antibacterial efficacy, UV-blocking ability, loss in weight, nitrogen content and durability to washing analysis. The obtained data reveal that the developed green wool fabrics exhibit outstanding durable antibacterial activity and UV-blocking ability for fabricating multi-functional textile products that can be utilized in a wide range of sustainable protective textiles, irrespective of the used post-finishing formulation ingredients. The results also show that both modification and functionalization processes are governed by the type of enzyme and kind of active material respectively. Moreover, the biosynthesized kerationlytic proteases could be accessibly used to remove protein-based stains like blood and egg.

Graphical abstract

     

Some Geometric Invariants of Pseudo-Spherical Evolutes in the Hyperbolic 3-Space

In this paper, we study the pseudo-spherical evolutes of curves in three dimensional hyperbolic space. We use techniques from singularity theory to investigate the singularities of pseudo-spherical evolutes and establish some relationships between singularities of these curves and geometric invariants of curves under the action of the Lorentz group. Besides, we defray with illustration some computational examples in support our main results.     

A simulation as a service cloud middleware

Many seemingly simple questions that individual users face in their daily lives may actually require substantial number of computing resources to identify the right answers. For example, a user may want to determine the right thermostat settings for different rooms of a house based on a tolerance range such that the energy consumption and costs can be maximally reduced while still offering comfortable temperatures in the house. Such answers can be determined through simulations. However, some simulation models as in this example are stochastic, which require the execution of a large number of simulation tasks and aggregation of results to ascertain if the outcomes lie within specified confidence intervals. Some other simulation models, such as the study of traffic conditions using simulations may need multiple instances to be executed for a number of different parameters. Cloud computing has opened up new avenues for individuals and organizations with limited resources to obtain answers to problems that hitherto required expensive and computationally-intensive resources. This paper presents SIMaaS, which is a cloud-based Simulation-as-a-Service to address these challenges. We demonstrate how lightweight solutions using Linux containers (e.g., Docker) are better suited to support such services instead of heavyweight hypervisor-based solutions, which are shown to incur substantial overhead in provisioning virtual machines on-demand. Empirical results validating our claims are presented in the context of two case studies.