Solventless synthesis of a Schiff base that forms highly fluorescent organic nanoparticles exhibiting aggregation-induced emission in aqueous media

A highly fluorescent solid state Schiff base compound (DBD) was synthesised using a green, solventless and fast approach in 30 sec. DBD shows almost no emission in THF solution, while it emits strong fluorescence in both dispersed nano-aggregates in the solution and as a powder, through a phenomenon known as aggregation-induced emission. Organic nanoparticles of DBD were prepared in aqueous solution using the nanoreprecipitation method with and without stabilizers. The nanoparticles exhibited strong, blue emission when the non-ionic surfactant, like triton X-100, was used as a stabilizer, and strong green emission when no surfactant or the cationic surfactant, like CTAB as a stabilizer was used. Using atomic force microscopy and dynamic light scattering, the sizes of the nanoparticles were found to be around 75 nm when prepared without surfactant, 50 nm when prepared using triton X-100, and 30 40 nm when prepared using CTAB. DBD nanoparticles show an emission maximum at 527 nm (pure green) in the cases of CTAB and no surfactant, while 400 nm emission is observed when triton X-100 is used. Finally, for practical applications, the new type of highly fluorescent organic nanoparticles (DBD) were chosen for on/off fluorescence switching nano sensor for detecting organic vapour.     

Complexation of furosemide with fulvic acid extracted from shilajit: a novel approach

The aim of the present work was to complex furosemide (FSM) with fulvic acid (FA) extracted from shilajit with the hope of having a better understanding of the complexation behavior. The effect of FA on the aqueous solubility, dissolution rate, and permeability of FSM was investigated. Different techniques, such as grinding, freeze drying, solvent evaporation, and so forth, were used for the preparation of the complex. The complexes were prepared in molar ratios of 1:1 and 1:2 FSM:FA and were evaluated for drug inclusion, solubility, differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, dissolution study, and permeation study. These methods confirm the formation of an amorphous inclusion complex of FSM with FA.     

Germania-based, sol-gel hybrid organic-inorganic coatings for capillary microextraction and gas chromatography

Germania-based, sol-gel hybrid organic-inorganic coatings were developed for capillary microextraction and gas chromatography (GC). Being an isostructural analogue of SiO2, GeO2 is compatible with the silica network. Because of this similarity, germania-based materials possess great potential for being used in the areas of chromatographic separation and sample preparation. These possibilities, however, remain practically unexplored. To our knowledge, this is the first instance that a germania-based hybrid sol-gel material is used as a sorbent in analytical sample preparation or chromatographic separation. Tetramethoxygermane was used as a precursor to create a sol-gel network via hydrolytic polycondensation reactions performed within a fused-silica capillary. The growing sol-gel germania network was simultaneously reacted with an organic ligand that contained sol-gel-active sites in its chemical structure. Three different sol-gel-active ligands were used: (a) hydroxy-terminated poly(dimethylsiloxane), (b) hydroxy-terminated poly(dimethyldiphenylsiloxane), and (c) 3-aminopropyltrimethoxysilane. Sol-gel germania-coated capillaries of desired polarity and extraction selectivity were prepared by using an appropriately selected sol-gel-active ligand in the sol solution. These capillaries were further used to extract trace concentrations of polycyclic aromatic hydrocarbons, aldehydes, ketones, alcohols, phenols, and free fatty acids from aqueous samples. The extracted solutes were further analyzed by GC-FID. The new germania-based coatings showed excellent stability under harsh operation conditions involving extreme pH values, high temperatures, and aggressive solvents. Our preliminary results also indicate that sol-gel hybrid germania coatings have the potential to offer great analytical performance as GC stationary phases.     

Efficacy of modified distillation sludge of rose (Rosa centifolia) petals for lead(II) and zinc(II) removal from aqueous solutions

Removal of lead(II) and zinc(II) from aqueous solutions was studied using chemically modified distillation sludge of rose (Rosa centifolia) petals by pretreatment with NaOH, Ca(OH)(2), Al(OH)(3), C(6)H(6), C(6)H(5)CHO and HgCl(2). The adsorption capacity of biomass was found to be significantly improved. NaOH pretreated biomass showed remarkable increase in sorption capacity. Maximum adsorption of both metal ions was observed at pH 5. When Freundlich and Langmuir isotherms were tested, the latter had a better fit with the experimental data. The overall adsorption process was best described by pseudo second order kinetics. The thermodynamic assessment of the metal ion-Rosa centifolia biomass system indicated the feasibility and spontaneous nature of the process and DeltaG degrees was evaluated as ranging from -26.9501 to -31.652 KJmol(-1) and -24.1905 to -29.8923KJmol(-1) for lead(II) and zinc(II) sorption, respectively, in the concentration range 10-640mgL(-1). Distribution coefficient (D) showed that the concentration of metal ions at the sorbent-water interface is higher than the concentration in the continuous aqueous phase. Maximum adsorption capacity of biomass tends to be in the order Pb(II) (87.74mgg(-1))>Zn(II) (73.8mgg(-1)) by NaOH pretreated biomass.     

Reactive power transfer allocation method with the application of artificial neural network

A novel method to identify the reactive power transfer between generators and load using modified nodal equations is proposed. On the basis of the solved load flow results, the method partitions the Y-bus matrix to decompose the current of the load buses as a function of the generators' current and voltage. Then it uses the load voltages from the load flow results and decomposed load currents to determine reactive power contribution from each generator to loads. The validation of the proposed methodology is demonstrated by using a simple 3-bus system and the 25-bus equivalent system of south Malaysia. Next part here focuses on creating an appropriate artificial neural network (ANN) to solve the same problem in a simpler and faster manner. The basic idea is to use supervised learning paradigm to train the ANN. Most commonly used feedforward architecture has been chosen for the proposed ANN reactive power transfer allocation technique. Almost all system variables obtained from load flow solutions are utilised as an input to the neural network. Moreover, tan-sigmoid activation functions are incorporated in the hidden layer to realise the nonlinear nature of the reactive power transfer allocation. The targets of the ANN corresponding to the previously developed reactive power transfer allocation method. The 25-bus equivalent system of south Malaysia is utilised as a test system to illustrate the effectiveness of the ANN output compared with that of the modified nodal equations method. The ANN output provides promising results in terms of accuracy and computation time.     

Role of urban greenway systems in planning residential communities: a case study from Egypt

Greenways have long played a significant role in the development of urban and sub-urban areas. They help mitigate the loss of “natural” space, often have scenic qualities, provide for recreation, education, a sense of well-being, and preservation of the natural habitat. This article explores the concept, history and development of urban greenways. The article illustrates the concept of linked parks and urban greenways in structuring urban and sub-urban developments while suggesting a methodological blueprint for their implementation in the planning process. A case study of a sub-urban development west of the city of Cairo, Egypt is presented to demonstrate the role of urban greenway systems in planning residential communities. An in-depth investigation of the planning process, context, approach, and development concept is followed by an overview of the rationale and significance of the method. The objective of this article is thus two-fold. First, to illustrate the concept of urban greenway systems in structuring communities; and second, to suggest a model for the integration and proper application of the concept of linked parks and urban greenway systems in planning residential communities. In conclusion, the article identifies a step-by-step procedure for integrating natural, recreational and cultural greenways and corridors in planning future residential developments.     

Thermochemical production of hydrogen from hydrogen sulfide with iodine thermochemical cycles

With the goal of eventually developing a replacement for the Claus process that also produces $H_2$, we have explored the possibility of decomposing hydrogen sulfide through a thermochemical cycle involving iodine. The thermochemical cycle under investigation leverages differences in temperature and reaction conditions to accomplish the unfavorable hydrogen sulfide decomposition to $H_2$ and elemental sulfur over two reaction steps, creating and then decomposing hydroiodic acid. This proposed process is similar to ideas put forth in the 1980s and 1990s by Kalina, Chakma, and Oosawa, but makes use of thermochemical hydrogen iodide decomposition methods and catalysts rather than electrochemical or photoelectrochemical methods.Process models describing a potential implementation of this thermochemical cycle were created. Motivated by the process model results, experimentation showed the possibility of using alternative solvents to dramatically decrease the energy requirements for the process. Further process modeling incorporated these alternative solvents and suggests that this theoretical hydrogen sulfide processing unit has favorable economic and environmental properties.     

Adsorptive potential of Acacia nilotica based adsorbent for chromium(VI) from an aqueous phase

The objective of this research was to enhance adsorption capacity of Acacia nilotica (keekar) sawdust for the abatement of chromium bearing wastewater and to investigate the effect of process parameters on adsorption capacity. The sawdust was activated by acid wash and functionalized subsequently with formaldehyde. Functionalization of activated sawdust raised its chromium removal efficiency of almost 10% as compared to its adsorption removal efficiency of HCl treated sawdust in a batch adsorption study. Adsorption kinetic data provided better fitting with pseudo second order model. Maximum adsorption capacity calculated through the best fitting Langmuir model was 6.34 mg·g^-1 and 8.2 mg·g^-1 for HCl treated and formaldehyde functionalized sawdust adsorbents, respectively. The adsorption of Cr(VI) was endothermic when studied by varying temperature from 20℃ to 50℃ for both activated and functionalized adsorbents.     

A Novel Auto-Scaling MPPT Algorithm based on Perturb and Observe Method for Photovoltaic Modules under Partial Shading Conditions

Maximum Power Point Tracking (MPPT) controller is required in a solar photovoltaic (PV) system to deliver the maximum power to load from PV module. This paper proposes a novel stepped MPPT method to realize a simple MPPT controller, which can track the real maximum power point (RMPP) even under partial shading conditions. The proposed algorithm is started by scanning the characteristic curve of the PV modules to detect the global maximum power point and then the algorithm will be switched to the conventional P&O algorithm to track the true maximum power point. The obtained simulation results, using Power electronic simulation software (PSIM), are compared with those found using the P&O method to confirm the performance of our proposed MPPT method even under non-uniform solar irradiation.     

Effect of Copper and Zirconium Addition on Properties of Fe-Co-Si-B-Nb Bulk Metallic Glasses

In this research work, iron-based bulk metallic glasses (BMGs) have been fabricated, characterized and compared with Fe-Si alloy. BMG alloys of composition ((Fe_0.6Co_0.4)_0.75B_0.20Si_0.05)₉₆Nb₄) were synthesized by suction casting technique using chilled copper die. Effect of copper and zirconium addition on magnetic, mechanical, thermal and electrochemical behavior of ((Fe_0.6Co_0.4)_0.75B_0.20Si_0.05)₉₆Nb₄ BMGs was investigated. Furthermore, effect of annealing on nano-crystallization and subsequently on magnetic and mechanical behavior was also analyzed. Amorphousness of structure was evidenced by XRD analysis and microscopic visualization, whereas nano-crystallization behavior was identified by peak broadening of XRD patterns. Magnetic properties, measured by vibrating sample magnetometer, were found to be improved for as-cast BMG alloys by copper addition and further enhanced by nano-crystallization after annealing. Mechanical properties were observed to be increased by zirconium addition while slightly declined by copper addition. Potentiodynamic polarization analysis manifested the positive role of zirconium in enhancing corrosion resistance of BMGs in acidic, basic and brine mediums. Moreover, mechanical properties and corrosion analysis results affirmed the superiority of BMG alloys over Fe-Si alloy.