Explore the vast range of titles available.

In this paper, the conjugate gradient method with a straightforward technique for obtaining the sensitivity coefficients is applied to solve the inverse transient radiative problems. Heat fluxes at different time steps serve as the measurement data to estimate the arbitrary distribution of absorption and/or scattering coefficients within one-dimensional variable index media. Transient variable discrete ordinates method is used to solve the transient radiative transfer equation and to obtain the time-resolved heat fluxes through the boundaries as desired values. To check the accuracy of conjugate gradient method, five different cases are investigated. The effects of random errors for measurement data on reconstruction accuracy are investigated. The results of inverse reconstruction show a good agreement with exact profiles for non-simultaneous or simultaneous estimation of absorption and scattering coefficients.

Catalytic activity of nano-flake ZnO for synthesis of quinoline derivatives and their related polyheterocycles under solventfree conditions has been studied. Nano-flake ZnO has been successfully synthesized by conventional heating of a solution approach using ZnOAc.2H2O and Urea. This method is simple, cost-effective, and environmentally benign and the catalyst can be reused for several times.

This paper presents an inverse analysis in one-dimensional ablation problem with the presence of a moving boundary to estimate the unknown applied heat flux at the surface of ablating materials. The estimated heat flux was used to obtain the location of moving front surface. The Sequential function specification method (SFSM) was implemented to minimize the least square objective function. Simulated temperature measurements at specific sensor positions inside the ablating materials were used in the inverse analysis. Due to the ill-posedness of the problem the number of future time steps was used as the regularizing parameter. We show that only a small number of future time steps is required to deal with the great nonlinearity of an inverse problem. The accuracy of applied inverse analysis was examined by functions containing sharp corners and discontinuities. Despite high nonlinearity, good estimations were obtained.

Nano-ZnO is reported as an extremely efficient heterogeneous catalyst for the synthesis of tetrahydrobenzo[b]pyrans. A three-component one-pot reaction of arylaldehydes, activated methylenes, and 1,3-diketones took place in water to afford the corresponding tetrahydrobenzo[b]pyrans in good to high yields in the presence of nano-ZnO. Furthermore, the catalyst could be reused for several times without any significant loss of its catalytic activity.

A new and environmentally benign method for the preparation of N-substituted pyrroles from one-pot condensation reaction of 2,5-dimethoxytetrahydrofuran with amines and diamines in the presence of nano sulfated titania under solvent-free conditions is presented. This new protocol features simple operation, easy availability, stability, and eco-friendliness of catalyst, as well as high to excellent yields of products. In addition, we report for the first time an alternative method for the synthesis of pyrroles from aromatic amines containing the β-lactam fragment using nano sulfated titania as catalyst.

An innovative route to preaper a number of variously substituted α-aminophosphonate is presented. The protocol avoids the use of any catalyst, organic solvents, and dry reaction conditions. The synthesis of α-aminophosphonates in the present study represents a three-component reaction in which no intermediate formation of either an imine or α-hydroxy phosphonate was observed.

In this work, an inverse forced convection–radiation boundary design problem for a two-dimensional channel with a forward and a backward-facing step is solved. In design problems, it is desired to provide uniform temperature and heat flux distribution over a design surface by obtaining the unknown temperature distribution over a heater surface. The flow is laminar, and the high-temperature gas is treated as an absorbing, emitting and isotropic scattering medium. The channel walls are considered to be diffuse-gray absorbers and emitters. The radiative transfer equation is solved by the discrete ordinates method. The conjugate gradient method which is based on an optimization technique is applied to solve the inverse problem. By the applied numerical method, the desired heat flux distribution over the design surface is very well reconstructed. Also, the effects of step inclination angle, scattering albedo and optical thickness on the solution of the present inverse problem are explored. It is found that by increasing in step inclination angle, scattering albedo and decreasing in the optical thickness, the total heat flux over the heater surface increases.

Sulfamic acid (SA) catalyses the nucleophilic opening of epoxide rings by amines leading to the efficient synthesis of ß-amino alcohols. The reaction works well with aromatic and aliphatic amines in short reaction times and in the absence of solvent. Exclusive trans stereoselectivity is observed for the ring opening of cyclohexene oxide. This method exhibits excellent regioselectivity for preferential nucleophilic attack at the less hindered position during the reaction with unsymmetrical epoxides.

Different long-term experiments were carried on chernozem (Debrecen) and loamy (Hajdúböszörmény) soils. They included the most important agrotechnical, biological (hybrid) and agroecological (crop year, soil) factors in maize production. This paper evaluated the results of polyfactorial long-term experiments. For the maize the most favourable crop rotation was winter wheat (in a tri-culture) with an N 60–120, P2O5 60–70, K2O and 90–110 kg ha−1, and a density of 75–90,000 plants ha−1. The different input levels of maize crop management systems can modify an adaptive capacity to ecological conditions and the resilience of agro-ecosystems. The optimalization of agrotechnical elements reduces the harmful climatic effects. The yields of maize varied between 2–11 t ha−1 in extensive and 10–15 t ha−1 in intensive crop management systems, respectively.