Studying the rheology,optical clarity and surface tension of an acrylic/melamine automotive clearcoat loaded with different additives

Acrylic/melamine based automotive clearcoats were prepared by inclusion of functional and conventional additives. The conventional additives used were based on polysiloxane chains without any reactive groups. On the other hand, the functional additives were based on polyacrylate and polysiloxane backbones. The additives were added to the clearcoat formulations at different concentrations. Surface tension, optical properties and rheological behaviors of the clearcoats were studied by tensiometer, gonio-spectrophotometer, rheometric mechanical spectrometer (RMS) and Brookfield techniques. Results showed that addition of both conventional and functional additives reduced the surface tension of the clearcoat up to a certain value of the additive concentration. It was seen that functional additives could reduce surface tension much greater than the conventional ones. The coating clarity and transparency were not affected in presence of conventional additives. However, the functional additives, especially the one having higher molecular weight, reduced the coating transparency. The clearcoat viscosity was increased using functional additives. A shear thickening behavior of the clearcoats loaded with functional additives was seen. The conventional additives did not change the clearcoat viscosity. It was concluded that the additive functionality, molecular weight and chemical structure were influential parameters affecting the final properties.     

Analysis of the atomic force microscopy vibration behavior using the Timoshenko theory by multi‐scale method in the air environment

This article deals with the modeling and simulation of the vibration behavior of piezoelectric micro‐cantilever (MC) based on the Timoshenko theory and using multi‐scale (MTS) method in the air environment. In this regard, the results are compared with the previous literature, such as the finite element method and the MTS method. The analysis of the piezoelectric MC vibrating behavior is investigated in a dynamical mode including non‐contact and tapping modes. The dynamics of this system is affected by interferential forces between probe tip and sample surface, such as van der Waals, capillary, and contact forces. According to the results, the forces applied to the probe tip reduce the amplitude and the resonance frequency. The simulation of surface topography in non‐contact mode and tapping for rectangular and wedge‐shaped roughness in the air environment are presented. Various experiments have been conducted in Ara research Company using the atomic force microscopy device in the amplitude mode. In the NSC15 Cantilever, the first natural frequency is derived from the results of the MC simulation based on Timoshenko beam theory, the practical results are 295.85 and 296.12 kHz, and the error rate is 0.09; at higher natural frequencies, the error rate has been increased. The γ _f coefficient is a measure of the nonlinear effects on the system; the effect of the piezoelectric length and width on γ _f coefficient is also investigated.     

Stabilisation mechanism of various inulins and hydrocolloids: Milk–sour cherry juice mixture

Milk–fruit juice mixtures, such as the mainly acidic nutraceutical soft drinks, usually suffer from phase separation due to aggregation of caseins at low pH. In this study, short‐chain inulin (SCI), native inulin (NI), long‐chain inulin (LCI) and a combination of long‐ and short‐chain inulins (LCI:SCI) (MIX) in different ratios (20:80, 50:50 and 80:20) were added (up to 10% w/v) to a milk–sour cherry juice mixture and their stabilisation mechanisms investigated using rheological, microstructural and zeta potential observations. In addition, gum tragacanth (GT) and Persian gum (PG) as adsorbing and guar gum (GG) as nonadsorbing hydrocolloids were combined with inulin to enhance their stabilising properties. Finally, sensory analyses were carried out on the stabilised samples. According to our findings, LCI fully stabilised the mixture (8% w/v), while LCI: SCI and NI only reduced phase separation at very high concentrations, and SCI had no significant effect on the stabilisation. Moreover, no inulin aggregates and rheological changes were observed with SCI. However, LCI, LCI: SCI and NI formed inulin aggregates and the mixtures became even more viscous and thixotropic (LCI > LCI: SCL > NI). Based on these observations, it can be concluded that chain length and concentration are two important factors that affect the functionality of inulin. On the other hand, the combination of inulin with GT and PG did not have any pertinent effect on the stabilisation. However, the mixture of inulin and GG could stabilise the mixtures at certain ratios and concentrations. Furthermore, in mixtures containing GG and SCI, GG played the main role in the stabilisation by increasing the viscosity and forming gel network.     

A multi-criteria context-sensitive approach for social image collection summarization

Recent increase in the number of digital photos in the content sharing and social networking websites has created an endless demand for techniques to analyze, navigate, and summarize these images. In this paper, we focus on image collection summarization. Earlier methods in image collection summarization consider representativeness and diversity criteria while recent ones also consider other criteria such as image quality, aesthetic or appeal. In this paper, we propose a multi-criteria context-sensitive approach for social image collection summarization. In the proposed method, two different sets of features are combined while each one looks at different criteria for image collection summarization: social attractiveness features and semantic features. The first feature set considers different aspects that make an image appealing such as image quality, aesthetic, and emotion to create attractiveness score for input images while the second one covers semantic content of images and assigns semantic score to them. We use social network infrastructure to identify attractiveness features and domain ontology for extracting ontology features. The final summarization is provided by integrating the attractiveness and semantic features of input images. The experimental results on a collection of human generated summaries on a set of Flickr images demonstrate the effectiveness of the proposed image collection summarization approach.     

Electromagnetic Scattering From Multilayer Rough Surfaces With Arbitrary Dielectric Profiles for Remote Sensing of Subsurface Soil Moisture

Radar remote sensing of soil moisture content at low frequencies requires an accurate scattering model of realistic soils, which often involves multilayer rough surfaces and dielectric profiles. In this paper, a hybrid analytical/numerical solution to two-dimensional scattering from multilayer rough surfaces separated by arbitrary dielectric profiles based on the extended boundary condition method (EBCM) and scattering matrix technique is presented. The reflection and transmission matrices of rough interfaces are constructed using EBCM. The dielectric profiles are modeled as stacks of piecewise homogeneous dielectric thin layers, whose scattering matrices are computed by recursively cascading reflection and transmission matrices of individual dielectric interfaces. The interactions between the rough interfaces and stratified dielectric profiles are taken into account by applying the generalized scattering matrix technique. The scattering coefficients are obtained by combining the powers computed from the resulting Floquet modes of the overall system. The bistatic scattering coefficients are validated against existing analytical and numerical solutions. Field-collected soil moisture data are then used for numerical simulations to investigate the penetration capability at different frequencies and to address the potential of low-frequency radar systems in estimating deep soil moisture. In particular, soil moisture profiles during dry ground, wet ground, and wet subsurface layer conditions are examined. The results show that both backscattering coefficients and copolarized phase difference at low frequencies are sensitive to the roughness of subsurface interfaces and deep soil moisture. Also, much larger depth sensitivity can be achieved using copolarized phase difference than scattering coefficients     

Effects of preweaning total plane of milk intake and weaning age on intake,growth performance,and blood metabolites of dairy calves

The objective of this study was to evaluate the effects of preweaning total plane of milk intake and weaning age on intake, growth performance, and blood metabolites of dairy calves. A total of 48 Holstein calves (40 ± 1.6 kg of body weight) were used in a 2 × 2 factorial arrangement with the factors of weaning age (d 60 vs. 75) and the total plane of milk intake (medium vs. high) during the preweaning period. Calves were assigned to 1 of 4 treatments: (1) calves fed medium plane of milk (MPM) intake and weaned on d 60 of age (MPM-60d, 4 L/d of milk from d 3 to 10, 6 L/d of milk from d 11 to 55, and 3 L/d of milk from d 56 to 60 of age; total milk intake = 317 L), (2) calves fed MPM intake and weaned on d 75 of age (MPM-75d, 4 L/d of milk from d 3 to 10 and 4.5 L/d of milk from d 11 to 70 of age followed by feeding 2.25 L/d of milk from d 71 to 75 of age; total milk intake = 313 L), (3) calves fed high plane of milk (HPM) intake and weaned on d 60 of age (HPM-60d, 4 L/d of milk from d 3 to 10, 6 L/d of milk from d 11 to 20, and 8.5 L/d of milk from d 21 to 55 followed by feeding 4.25 L/d of milk from d 56 to 60 of age; total milk intake = ～411 L); and (4) calves fed HPM intake and weaned on d 75 (HPM-75d, 4 L/d of milk from d 3 to 10, and 6 L/d of milk from d 11 to 70 of age followed by feeding 3 L/d of milk from d 71 to 75 of age; total milk intake = 407 L) with no milk refusals. All of the calves were monitored up to d 90 of age. Regardless of weaning age, starter feed intake and dry matter intake (% of body weight) were lower in calves fed HPM compared with those receiving MPM. A tendency for the plane of milk intake × weaning age interaction was observed for metabolizable energy intake with the highest value was recorded with the HPM-75d calves. The lowest efficiency of metabolizable energy intake and average feed efficiency was observed in HPM-60d calves throughout the experimental period as compared with the other groups. An interaction was found between the total plane of milk intake and weaning age regarding effects on total average daily gain, average daily gain/metabolizable energy intake, feed efficiency, final body weight, and plasma β-hydroxybutyrate levels with the highest values measured in HPM-75d calves. Weaning on d 75 versus d 60 improved wither height and hip width, which tended to increase body length at the end of the trial. The results suggest that calves fed high amounts of milk during their preweaning period benefit from extending the time of weaning from 60 to 75 d of age based on average daily gain, feed efficiency, and final body weight.     

A Regioselective Approach to Synthesize Indolyl Diketone Derivatives via Magnetic Polymeric Copper-Catalyst

Catalysis Letters - In the present paper, an efficient Cu-catalyzed regioselective acylation of indoles with phenylglyoxals was developed which is the first example of indolyl diketones synthesis...     

Electrodeposition of nickel oxide nanoparticles on glassy carbon surfaces: application to the direct electron transfer of tyrosinase

This work describes the performance of a tyrosinase/nickel oxide nanoparticles/glassy carbon (Tyr/NiO NPs/GC) electrode. This electrode was prepared by first applying a NiO NPs electrochemical deposition onto the GC electrode surface and then tyrosinase immobilization was applied to the surface of electrodeposited NiO NPs. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) procedures demonstrated the existence of different NiO NP geometrical structures. These geometrical structures could lead to better immobilization of proteins on their surfaces. The copper containing enzyme tyrosinase successfully achieved electrical contact with the electrode because of the unique structural alignment of tyrosinase enzyme on the nanometer-scale nickel oxide surfaces. This method could be suitable for application to nanofabricated devices facilitating better performance. It was concluded that tyrosinase can be effectively applied to nanometer-scale nickel oxide surfaces.