A search-based identification of variable microservices for enterprise SaaS

Recently, SaaS applications are developed as a composition of microservices that serve diverse tenants having similar but different requirements, and hence, can be developed as variability-intensive microservices. Manual identification of these microservices is difficult, time-consuming, and costly, since, they have to satisfy a set of quality metrics for several SaaS architecture configurations at the same time. In this paper, we tackle the multi-objective optimization problem of identifying variable microservices aiming optimal granularity (new metric proposed), commonality, and data convergence, with a search-based approach employing the MOEA/D algorithm. We empirically and experimentally evaluated the proposed method following the Goal-Question-Metric approach. The results show that the method is promising in identifying fully consistent, highly reusable, variable microservices with an acceptable multi-tenancy degree. Moreover, the identified microservices, although not structurally very similar to those identified by the expert architects, provide design quality measures (granularity, etc.) close to (and even better than) the experts.     

FSCVG: A Fuzzy Semi-Distributed Clustering Using Virtual Grids in WSN

Wireless Personal Communications - Wireless sensor network comprises of tiny devices which are powered by limited energy resources. Therefore, providing methods to reduce energy consumption is...     

Synthesis and Structural Characterization of Novel Nanostructured Aromatic Optically Active Poly(Ester–Amide)s Derived from S-tyrosine Containing Symmetric Diol and Aromatic Diacid Chlorides

In this study, at first N,N′-bis[2-(methyl-3-(4-hydroxyphenyl)propanoate)]terephthaldiamide, as a new chiral monomer based on tyrosine amino acid, was synthesized from the reaction of S-tyrosine methyl ester and terephthaloyl dichloride. Then novel nanostructured aromatic optically active and eco-friendly poly(ester–amide)s based on tyrosine amino acid were synthesized by the solution polycondensation of the new diol and a number of aromatic diacid chlorides. The resulting poly(ester–amide)s exhibited good yields, solubility, inherent viscosities, and thermal stability. All polymers were characterized by Fourier transform infrared, ¹H NMR, elemental analysis, and specific rotation. They were also studied by X-ray diffraction, thermogravimetric analysis, and field emission scanning electron microscopy.     

The effect of nanoliposomal formulations on Staphylococcus epidermidis biofilm

Objective: The aim of the present study was to assess the in vitro antimicrobial activities of nanoliposomal formulations loaded with vancomycin or/and rifampin against the biofilm formed by Staphylococcus epidermidis at 37?°C under aerobic condition.

Materials and methods: Liposomal formulations were prepared by dehydration-rehydration (DRV) method and characterized for size, zeta potential and encapsulation efficacy. The ability of different formulations on eradication of bacterial biofilm was assessed through optical density ratio (OD_r) and the results implicate higher survival rates of S. epidermidis on biofilm. Positive control was defined as an OD_r?=?1.0.

Results: The zeta potential of anionic, cationic and PEGylated liposomes was ?35?±?2, 35?±?1 and 27?±?2?mV whereas the mean sizes of these liposomal formulations were 145?±?4, 134?±?1 and 142?±?6?nm, respectively. Encapsulation efficacy of rifampin and vancomycin was more than 60% and about 25%, respectively. Cationic liposomal rifampin lowered the OD_r to 0.61 and was the most effective formulations against S. epidermidis biofilm (p?Conclusion: The results of this study showed that rifampin-loaded liposomes were effective against bacterial biofilm.     

Optimizing the electrospinning conditions of polysulfone membranes for water microfiltration applications

Polysulfone (PSU) is a popular material in microfiltration applications. In this study, the preparation of PSU membranes via electrospinning technology was investigated and optimized. Solutions with three different concentrations (15, 20 and 25 wt%) of PSU in dimethylformamide were electrospun at three different feed rates (1.5, 2.5 and 3.5 mL h^?1) and voltages (12.5, 15 and 18 kV). The morphologies of the samples were studied using SEM. The results showed that the samples prepared from a 15 wt% solution concentration have beads‐on‐string morphologies. As the solution concentration is increased to 20 and 25 wt%, the beads disappear and uniform fibers with average diameters ranging from 0.876 to 2.078 μm depending on the voltage and the feed rate are obtained. The optimum electrospinning conditions for the highest wettability with minimum operating pressure were predicted to be a solution concentration of 25 wt%, a feed rate of 3.5 mL h^?1 and a voltage of 18 kV. The prediction was verified by contact angle test measurements and filtration experiments. © 2019 Society of Chemical Industry     

Finite element modeling of the flow of a rubber compound through an axisymmetric die using the CEF viscoelastic constitutive equation

This work is devoted to the simulation of the flow of a high viscosity NR/SBR rubber compound through the die of a single screw extruder with axisymmetric geometry. An in-house developed computer code based on the use of continuous penalty finite element method was employed. Three constitutive equations including two generalized Newtonian models namely; power-law and Carreau and an explicit viscoelastic model named CEF (Criminale-Ericksen-Fillbey) were used to reflect the rheological behavior of the material. Using the parameters of the rheological models determined by a slit die rheometry technique, the flow of the compound was simulated through the die and results were compared with experimentally measured mass flow rates. It is shown that for high viscosity rubber compounds the use of generalized Newtonian models which do not take the normal stress in simple shear flow into consideration gives rise to significant errors in prediction of mass flow rates. On the other hand, comparing the simulations results using the CEF equation with experimental data revealed that this model is the best compromise between generalized Newtonian and full viscoelastic models which need high computational costs and effort. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Physicochemical Characteristics of Starch Component of Wheat Flours Obtained from Fourteen Iranian Wheat Cultivars

In this study, the differences in the physicochemical properties of starch component of fourteen Iranian wheat cultivars (Triticum aestivum L.) in terms of thermal, pasting and gel properties were studied. Positive correlations between the apparent amylose content and the gelatinization temperature (r = 0.8) and also the gel strength (r = 0.7) of different samples were established. There was no correlation between the amylose content and pasting properties. Moreover a positive relationship between the peak and final viscosities of different wheat flours (r = 0.8) was found. It was concluded that well selection of wheat cultivars is critical for production of high quality products. For this reason, all factors influencing the quality of wheat or flour should be studied carefully. Commonly yield, weight, protein content and quality have been mentioned as quality factors, however as this study indicated, the physicochemical properties of starch should also be considered as a quality criterion.     

A novel foam-like silane modified alumina scaffold coated with nano-hydroxyapatite–poly(ε-caprolactone fumarate) composite layer

Although alumina scaffolds with biodegradable polymer coating can overcome the limitations of conventional ceramic bone substitutes, the bioactivity potential of these scaffolds needs to be enhanced. In this study, the macroporous alumina scaffolds with the defined pore-channel interconnectivity were successfully prepared by the foam replication method. The average pore size of the scaffolds was in the range 200–900 μm with around 82% porosity. The average Young's modulus of alumina scaffolds was 2.8 GPa. Coating of nano-hydroxyapatite (nano-HA) in poly(ε-caprolactone fumarate) (PCLF) as a carrier on the surface of alumina scaffold was performed. The nano-HA powder was synthesized successfully by the sol–gel method. The crystallite and particle sizes of HA powders were in nano range and confirmed by the Scherrer equation from X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The PCLF was synthesized and characterized by fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). In order to make a chemical link between the alumina scaffolds and the coating, a silane coupling agent was used. The results showed that using of 1 g Methacryloxypropyl trimethoxysilane in 100 g solvent is sufficient for making a thin interface layer between the scaffold and the polymer. The coating process was performed by immersion of scaffolds in the solutions with different percents of nano-HA. The morphology and chemical structure of the coated scaffolds were investigated by SEM and FTIR. SEM images demonstrated that the scaffolds were constituted of interconnected and homogeneously distributed pores. Also, HA distribution and agglomerates on the surface of scaffolds were enhanced by increasing the nano-HA percent in the coating solutions.     

Advanced development in upstream of petroleum industry using nanotechnology

Nowadays, energy supply is one of the most important issues due to limitation of oil, gas and coal sources. Because of rapid population, civilization and energy consumption growth, the improved technologies to make optimal use of the sources, solving related problems and finding new energy sources are important. More than 10 years ago, nanotechnology as one of the most important technologies has also been applied to progress in the oil and gas industry (upstream, midstream and downstream). The experience of these years has shown that application of nanotechnology in the oil industry improves the exploration of crude oil and natural gas (underground or deep water), drilling and bringing the crude oil or raw natural gas to the surface, as well as transportation, storage, processing and purifying methods. Nanoparticles with high specific surface area, pore volume and small size show unique physical and chemical properties, which could be applied in several applications. In this regard, many researchers have been focused on various nanoparticles for upstream industries and studied their potential in oil exploration, drilling, production and enhanced oil recovery (EOR). Also, in downstream and midstream which involve refining of crude oil, processing and purifying of raw natural gas, transportation and storage of crude or refined petroleum products, the nanomaterials have been used to improve the quality of oil and make it appropriate for the environment. Lowering sulfur gasoline, enhancing the octane number and coating the transportation system are among the goals that have been achieved successfully using nanotechnology. In this work, various types of nanoparticles such as metallic, metal oxide, hybrid nanoparticles, carbon nanomaterials, nano-composites and their applications in oil upstream industry are reviewed. Also, their usage in different types of oil upstream processes is discussed.