Comparison of mechanical and optical properties of a newly marketed universal composite resin with contemporary universal composite resins: An in vitro study

The purpose of this study was to evaluate the surface roughness, microhardness, color change, and translucency of a newly marketed universal nanohybrid composite resin (CR) (G-aenial A'CHORD) comparing with four contemporary universal CRs including two nanofilled (Filtek and Estelite Asteria) and two nanohybrid CRs (Charisma Dimond and Neo Spectra ST HV in vitro). Sixty-five specimens (8.0 mm × 2.0 mm) were fabricated (n = 13, per group). After finishing and polishing, specimens were subjected to surface roughness and microhardness tests. Color and translucency of the specimens were evaluated at baseline and after darkening with coffee solution at day 1 and day 7. A representative specimen from each group was investigated under scanning electron microscopy (SEM). Data was analyzed statistically (p < .05). There were significant differences among the groups in terms of surface roughness, microhardness, color, and translucency. The surface roughness was recorded as: Charisma Diamond > Neo Spectra ST HV, Filtek > Estelite Asteria, G-aenial A'CHORD, whereas Vickers Hardness number was as: Filtek, Charisma Diamond > Neo Spectra ST HV > G-aenial A'CHORD, Estelite Asteria. Color change was as: Charisma Diamond > Neo Spectra ST HV, Filtek, G-aenial A'CHORD > Estelite Asteria and the translucency was as: Neo Spectra ST HV > G-aenial A'CHORD, Filtek > Estelite Asteria, Charisma Diamond. SEM examinations revealed smooth surfaces for G-aenial A'CHORD, Neo Spectra ST HV and Estelite Asteria. Mechanical and optical properties of universal composite resins with different compositions show variations.     

Effect of Steam Baking on Acrylamide Formation and Browning Kinetics of Cookies

Abstract: Effects of baking method and temperature on surface browning and acrylamide concentration of cookies were investigated. Cookies were baked in natural and forced convection and steam‐assisted hybrid ovens at 165, 180, and 195 °C and at different times. For all oven types, the acrlyamide concentration and surface color of cookies increased with increasing baking temperature. Significant correlation was observed between acrylamide formation and browning index, BI, which was calculated from Hunter L, a, and b color values, and it showed that the BI may be considered as a reliable indicator of acrylamide concentration in cookies. Acrylamide formation and browning index in cookies were considered as the first‐order reaction kinetics and the reaction rate constants, k, were in the range of 0.023 to 0.077 (min^?1) and 0.019 to 0.063 (min^?1), respectively. The effect of baking temperature on surface color and acrylamide concentration followed the Arrhenius type of equation, with activation energies for acrylamide concentration as 6.87 to 27.84 kJ/mol; for BI value as 19.54 to 35.36 kJ/mol, for all oven types. Steam‐assisted baking resulted in lower acrylamide concentration at 165 °C baking temperature and lower surface color for all temperatures. Steam‐assisted baking is recommended as a healthy way of cooking providing the reduction of harmful compounds such as acrylamide for bakery goods, at a minimal level, while keeping the physical quality. Practical Application: The kinetics of acrylamide formation and browning of cookies will possibly allow definition of optimum baking temperatures and times at convectional and steam‐assisted baking ovens. The kinetic model can be used by developing baking programs that can automatically control especially a new home‐scale steam‐assisted hybrid oven producing healthy products, for the use of domestic consumers.     

Spray Drying of Yogurt: Optimization of Process Conditions for Improving Viability and Other Quality Attributes

Plain yogurt was subjected to spray drying to determine the optimum processing conditions that yield maximum survival ratio of lactic acid bacteria, maximum overall sensory attributes, minimum color change, and acceptable moisture content. The inlet (150–180°C) and outlet air temperatures (60–90°C) and the feed temperature (4–30°C) were the independent factors. A pilot-scale spray dryer was used to conduct a set of drying experiments where the process conditions were selected according to central composite rotatable design (CCRD). The resulting yogurt powder at each condition was also subjected to the measurement of some physical properties (water activity, titratable acidity [lactic acid, %] and pH) to determine the effects of spray-drying conditions. The morphological structure of the powder was inspected by scanning electron microscopy (SEM) analysis. Optimization by the application of the desirability function method resulted in air inlet temperature of 171°C, air outlet temperature of 60.5°C, and feed temperature of 15°C as the optimum processing condition. The mathematical optimum condition was experimentally verified.     

A general framework for time-aware decision support systems

In this paper we present a general framework for time-aware decision support systems. The framework uses the state-of-the-art tOWL language for the representation of temporal knowledge and enables temporal reasoning over the information that is represented in a knowledge base. Our approach uses state-of-the-art Semantic Web technology for handling temporal data. Through such an approach, the designer of a system can focus on the application intelligence rather than enforcing/checking data related restrictions manually. Also, there is an increased support for reuse of temporal reasoning tools across applications. We illustrate the applicability of our framework by building a market recommendations aggregation system. This system automatically collects market recommendations from online sources and, based on the past performance of the analysts that issued a recommendation, generates an aggregated recommendation in the form of a buy, hold, or sell advice. We illustrate the flexibility of our proposed system by implementing multiple methods for the aggregation of market recommendations.     

Pilot plant study of desalination by direct contact heat transfer

A pilot plant was constructed to study desalination by direct contact liquid-liquid heat transfer. A refined mineral oil was used as the heat carrier.The system could be used successfully to produce fresh water while eliminating corrosion and wear to a large extent. Trace quantities of oil dissolved in the product water could be removed by adsorption over activated charcoal, which could subsequently be activated by live steam.The by-product brine has a high concentration offering greater value and less problems for disposal.     

Weighted Constraint Aggregation in Fuzzy Optimization

Many practical optimization problems are characterized by some flexibility in the problem constraints, where this flexibility can be exploited for additional trade-off between improving the objective function and satisfying the constraints. Fuzzy sets have proven to be a suitable representation for modeling this type of soft constraints. Conventionally, the fuzzy optimization problem in such a setting is defined as the simultaneous satisfaction of the constraints and the goals. No additional distinction is assumed to exist amongst the constraints and the goals. This paper proposes an extension of this model for satisfying the problem constraints and the goals, where preference for different constraints and goals can be specified by the decision-maker. The difference in the preference for the constraints is represented by a set of associated weight factors, which influence the nature of trade-off between improving the optimization objectives and satisfying various constraints. Simultaneous weighted satisfaction of various criteria is modeled by using the recently proposed weighted extensions of (Archimedean) fuzzy t-norms. The weighted satisfaction of the problem constraints and goals are demonstrated by using a simple fuzzy linear programming problem. The framework, however, is more general, and it can also be applied to fuzzy mathematical programming problems and multi-objective fuzzy optimization.     

Fuzzy arithmetic-based interpolative reasoning for nonlinear dynamic fuzzy systems

FAIR (fuzzy arithmetic-based interpolative reasoning)—a fuzzy reasoning scheme based on fuzzy arithmetic, is presented here. Linguistic rules of the Mamdani type, with fuzzy numbers as consequents, are used in an inference mechanism similar to that of a Takagi–Sugeno model. The inference result is a weighted sum of fuzzy numbers, calculated by means of the extension principle. Both fuzzy and crisp inputs and outputs can be used, and the chaining of rule bases is supported without increasing the spread of the output fuzzy sets in each step. This provides a setting for modeling dynamic fuzzy systems using fuzzy recursion. The matching in the rule antecedents is done by means of a compatibility measure that can be selected to suit the application at hand. Different compatibility measures can be used for different antecedent variables, and reasoning with sparse rule bases is supported. The application of FAIR to the modeling of a nonlinear dynamic system based on a combination of knowledge-driven and data-driven approaches is presented as an example.     

A regression-based approach for estimating preliminary dimensioning of reinforced concrete cantilever retaining walls

Structural and Multidisciplinary Optimization - The reinforced concrete cantilever retaining walls (RCCRWs) are among the most commonly used type of structures to support the soil in civil...     

Fuzzy optimization of slab production from mechanical stone properties

This paper aims to conduct slab production optimization by a flexible tool, which is fuzzy linear programming. There is a direct relationship between slab production and mechanical stone characteristics. In this process, the goal and its tolerance cannot be specified firstly due to a lack of knowledge. Therefore, the optimal system design problem for optimal slab production under soft constraints is constructed and solved in a fuzzy environment. The results show that fuzzy linear optimization is a convenient tool for optimizing slab production.     

Quantitative comparison of dynamic controllability between a reactive distillation column and a conventional multi-unit process

A comparison of the steady-state economic optimum designs of two alternative chemical processes was presented in a previous paper [Kaymak, D. B., & Luyben, W. L. (2004). A quantitative comparison of reactive distillation with conventional multi-unit reactor/column/recycle systems for different chemical equilibrium constants. Industrial & Engineering Chemistry Research, 43, 2493–2507]. A generic exothermic reversible reaction A + B ↔ C + D occurs in both flowsheets, which consist of a conventional multi-unit reactor/separator/recycle structure and a reactive distillation column. Results showed that the reactive distillation process is significantly less expensive than the conventional process for a wide range of the chemical equilibrium constant when there is no mismatch between the temperature favorable for reaction and the temperature favorable for vapor–liquid separation.

A reactive distillation column has fewer control degrees of freedom than a conventional multi-unit system. Therefore a reactive distillation column may have worse dynamic response than a conventional process. The purpose of this paper is to compare the dynamic controllability of these two alternative processes.

Three different chemical equilibrium constants are considered. Several control structures are developed for each flowsheet, and their effectiveness is evaluated. Disturbances in production rate and fresh feed compositions are considered.

The conventional multi-unit process provides significantly better control. The operability region is much larger, there is less variability in product quality and the dynamic responses are faster than those of the reactive column. Thus, these results demonstrate that there is a significant trade-off in this system between optimum economic steady-state design and dynamic controllability.