An Indicator Based Assessment for Water Resources Management in Gediz River Basin,Turkey

In this study, a water resources management model that facilitates indicator-based decisions with respect to environmental, social and economic dimensions is developed for the Gediz River Basin in Turkey. The basic input of the proposed model is the quantity of surface water that is greatly allocated to irrigation purposes; therefore, supply and demand interrelations in agricultural water use constitute the main focus of the study. The model has been applied under three different hydro-meteorological scenarios that reflect baseline as well as better and worse conditions of water supply and demand, not only to reach an assessment of water budget, but also to evaluate the impacts of proposed management alternatives under different conditions. The Water Evaluation and Planning (WEAP) software is used as a simulation and evaluation tool to assess the performance of possible management alternatives, which is measured by nine proposed indicators. The results of the study have indicated that the Gediz River Basin is quite sensitive to drought conditions, and the agricultural sector is significantly affected by irrigation deficits that increase sharply in drought periods. Even if the optimistic scenario is assumed to occur, it is not possible to observe a significant improvement in the water budget; however, the negative impacts of climate change can possibly exacerbate the water crisis. The indicators also verified that, efficient water management is crucial to ensure the sustainable use of water resources with respect to environmental, social and economic dimensions.     

A numerical simulation study for the human passive thermal system

The objective of this study is to create a dynamic model representing a transient three-dimensional passive thermal model of the human body. The model is a multi-segmental, multi-layered representation of the human body with spatial subdivisions which simulates the heat transfer phenomena within the body and at its surface. In order to represent the mechanisms of heat transfer within the body, energy balance equations including conduction with adjacent tissue, heat storage, metabolic heat generation, and convective heat transfer due to the blood flow in the capillaries are taken into consideration for each tissue. The present model of the passive system accounts for the geometric and anatomic characteristics of the human body and considers the thermo-physical and the basal physiological properties of tissue materials. It is assumed that the body is exposed to combination of the convection, evaporation and radiation which are taken into account as boundary conditions when solving the passive thermal system equation. The model is capable of predicting human body temperature in any given environmental conditions. Finite difference solution scheme is used to find out the temperature distribution of human body. The results are compared with the experimental data of previous studies present in the literature. Consequently, the numerical results of present model show good agreement with the experimental data.     

Thermally curable main-chain benzoxazine prepolymers via polycondensation route

Polybenzoxazines are addition-cure thermosetting polymers exhibiting versatility in a wide range of applications due to their good mechanical properties, dimensional stability, chemical resistivity, flame resistance property phenolic or epoxy resins have myriad applications in diverse fields starting from commodity materials to high technology aerospace industries. In this paper, we present synthetic strategies to incorporate thermally curable benzoxazine functionality into polymers as main-chain fashion in order to further improve various properties. The strategies successfully employed including monomer synthesis and polycondensation routes like Mannich reaction, click chemistry, hydrosilylations, and coupling reactions. The structure–property relationships of the cured materials have also been presented and discussed.     

Isolation of some active compounds from Origanum vulgare L. ssp. vulgare and determination of their genotoxic potentials

Origanum vulgare L. (oregano) is a flavoring herb widely used around the world. In the present study, crude extract of O. vulgare L. (oregano) and its petroleum ether, chloroform, ethyl acetate, n-butanol, water fractions were prepared in order to isolate and investigate antimutagenic compounds from the active extract through the bacterial genotoxicity assay guided fractionation procedures. The methanol extract and its n-butanol fraction showed significant antimutagenic activity. In the end of sub-fractionation process of the n-butanol extract, luteolin 7-O-glucuronide and luteolin 7-O-xyloside were isolated. These compounds showed significant antimutagenic activity against 9-Aminoacridine and N-Methyl-N′-nitro-N-nitrosoguanidine mutagenicity. The inhibition rates ranged from 22.1% (luteolin 7-O-xyloside: Salmonella typhimurium TA1537 – 0.4 mM/plate) to 67.8% (luteolin 7-O-glucuronide: S. typhimurium TA1537 – 0.8 μM/plate). In conclusion, the results revealed that luteolin 7-O-glucuronide and luteolin 7-O-xyloside are two of the antimutagenic compounds of O. vulgare L. ssp. vulgare.     

Synthesis and Characterization of Polyacetylene with Side-chain Thiophene Functionality

A new polyacetylene derivative with electroactive thiophene substituent, namely poly(2-methylbut-2-enyl thiophene-3-carboxylate) was synthesized and characterized. For this purpose, novel acetylene monomer was synthesized by the reaction of 3-thiophenecarboxylic acid with propargyl bromide and polymerized with a Rh catalyst to give the corresponding polymer. The chemical structure of the polymer was characterized to comprise the conjugated backbone and electroactive thiophene side group. UV spectral changes of the polymer with temperature were also studied. The polymer exhibited better thermal stability than the unsubstituted polyacetylenes.     

Linear eddy mixing based tabulation and artificial neural networks for large eddy simulations of turbulent flames

A large eddy simulation (LES) sub-grid model is developed based on the artificial neural network (ANN) approach to calculate the species instantaneous reaction rates for multi-step, multi-species chemical kinetics mechanisms. The proposed methodology depends on training the ANNs off-line on a thermo-chemical database representative of the actual composition and turbulence (but not the actual geometrical problem) of interest, and later using them to replace the stiff ODE solver (direct integration (DI)) to calculate the reaction rates in the sub-grid. The thermo-chemical database is tabulated with respect to the thermodynamic state vector without any reduction in the number of state variables. The thermo-chemistry is evolved by stand-alone linear eddy mixing (LEM) model simulations under both premixed and non-premixed conditions, where the unsteady interaction of turbulence with chemical kinetics is included as a part of the training database. The proposed methodology is tested in LES and in stand-alone LEM studies of three distinct test cases with different reduced mechanisms and conditions. LES of premixed flame–turbulence–vortex interaction provides direct comparison of the proposed ANN method against DI and ANNs trained on thermo-chemical database created using another type of tabulation method. It is shown that the ANN trained on the LEM database can capture the correct flame physics with accuracy comparable to DI, which cannot be achieved by ANN trained on a laminar premix flame database. A priori evaluation of the ANN generality within and outside its training domain is carried out using stand-alone LEM simulations as well. Results in general are satisfactory, and it is shown that the ANN provides considerable amount of memory saving and speed-up with reasonable and reliable accuracy. The speed-up is strongly affected by the stiffness of the reduced mechanism used for the computations, whereas the memory saving is considerable regardless.     

Patient‐specific phosphorus mobilization clearance during nocturnal and short daily hemodialysis

The kinetics of plasma phosphorus during different hemodialysis (HD) modalities are incompletely understood. We recently demonstrated that a pseudo one‐compartment kinetic model including phosphorus mobilization from various body compartments into extracellular fluids can describe intradialytic and postdialytic rebound kinetics of plasma phosphorus during conventional and short 2‐hour HD treatments. In this model, individual patient differences in phosphorus kinetics were characterized by a single parameter, the phosphorus mobilization clearance (K_M). In this report we determined K_M in patients treated by in‐center nocturnal HD (ICNHD) and short daily HD (SDHD) with low dialyzer phosphate clearance. In the ICNHD study, eight patients underwent 8‐hour HD treatments where intradialytic and postdialytic plasma samples were collected; K_M values were determined by nonlinear regression of plasma concentration as a function of time. In the SDHD study, five patients were studied during 28 treatments for approximately 3 hours. Here, K_M was calculated using only predialytic and postdialytic plasma phosphorus concentrations. Dialyzer phosphate clearances were 134 ± 20 (mean ± SD) and 95 ± 16 mL/min during ICNHD and SDHD, respectively. K_M values for the respective therapies were 124 ± 83 and 103 ± 33 mL/min, comparable to those determined previously during conventional and short HD treatments of 98 ± 44 mL/min. When results from ICNHD, SDHD, and previous HD modalities were combined, K_M was directly correlated with postdialytic body weight (r = 0.38, P = 0.025) and inversely correlated with predialytic phosphorus concentration (r = ?0.47, P = 0.005). These findings suggest that phosphorus kinetics during various HD modalities can be described by a pseudo one‐compartment model.     

Synthesis and characterization of thermally curable polyacetylenes by polymerization of propargyl benzoxazine using rhodium catalyst

A novel acetylene monomer containing benzoxazine group was synthesized and polymerized with [(norbornadiene)rhodium(I) chloride]₂ ([(nbd)RhCl]₂) to give the corresponding polymer. The effect of triethylamine as co-catalyst in the polymerization was investigated. The spectral and thermal analyses confirmed the presence of benzoxazine functionality in the resulting polymer. It is shown that polyacetylene containing benzoxazine side groups undergoes irreversible cis–trans isomerization and thermally activated curing in the absence of any catalyst forming polyacetylene thermoset with high thermal stability.     

Nanoscale Origins of Nonlinear Behavior in Ferroic Thin Films

The nonlinear response of a ferroic to an applied field has been studied through the phenomenological Rayleigh Law for over a hundred years. Yet, despite this, the fundamental physical mechanisms at the nanoscale that lead to macroscopic Rayleigh behavior have remained largely elusive, and experimental evidence at small length scales is limited. Here, it is shown using a combination of scanning probe techniques and phase field modeling, that nanoscale piezoelectric response in prototypical Pb(Zr,Ti)O₃ films appears to follow a distinctly non‐Rayleigh regime. Through statistical analysis, it is found that an averaging of local responses can lead directly to Rayleigh‐like behavior of the strain on a macroscale. Phase‐field modeling confirms the twist of the ferroelastic interface is key in enhancing piezoelectric response. The studies shed light on the nanoscale origins of nonlinear behavior in disordered ferroics.