Stability of Dye Dispersions in the Presence of Some Eco-Friendly Dispersing Agents

The stability of dye dispersions in the presence of ethoxylated sorbitan lauryl and oleyl esters were reported and compared with dye dispersions containing a conventional dispersing agent, i.e. naphthalene sulfonic acid methylene-bis sodium salt (NSAB). The optimum operating conditions obtained using a central composite design and stability of dye dispersions were evaluated by a turbidimetry method. Results showed that the dose of surfactants and the temperature of operation were important factors in preparing stable dye dispersions. Also, the best conditions for preparing dye dispersions were as follows: dose of surfactant 0.05 g, temperature 25 °C and time 5 min. In addition to, findings indicated that both of the used surfactants had better performance in dispersing the dyes in water. However, ethoxylated sorbitan oleate had better efficiency relative to other used dispersing agents. The performance of both sorbitan esters were compared with NSAB. The results indicated that they can create stable dye dispersions in aqueous media and have approximately the same effectiveness with NSAB. In this series, although oleate ester had a better performance than the laurate, the difference in performance of using dispersing agents was not significant. This finding was confirmed by the results of the particle size analysis of dye dispersions.     

Application of carbon nanostructures toward SO2 and SO3 adsorption: a comparison between pristine graphene and N-doped graphene by DFT calculations

We studied the adsorption of SO_x (x?=?2,3) molecules on the surface of pristine graphene (PG) and N-doped graphene (NDG) by density functional theory (DFT) calculations at the B3LYP/6-31G(d) level. We used Mulliken and NBO charge analysis to calculate the net charge transfer of adsorbed SO_x on pristine and defected graphene systems. Our calculations reveal much higher adsorption energy and higher net charge transfer by using NDG instead of pristine graphene. Furthermore, the density of state (DOS) graphs point to major orbital hybridization between the SO_x and NDG, while there is no evidence of hybridization by using pristine graphene. Based on our results, it is found that SO₂ and SO₃ molecules can be adsorbed on the surface of NDG physically and chemically with adsorption energies (E_ads) of ?27.5 and 65.2?kJ?mol^?1 (19.6 and 51.4?kJ?mol^?1 BSSE), respectively, while low adsorption energies were calculated in the case of using pristine graphene. So we introduced NDG as a sensitive adsorbent/sensor for detection of SO₂ and SO₃.     

Gaseous Mixtures Separation via Chemically-Activated Nano Silica-Modified Carbon Molecular Sieves

Silicon - The goal of this research was to study the efficiency of the silica-modified, highly selective synthesized carbon molecular sieves for nitrogen separation in the methane purification...     

Synthetic C-oligosaccharides mimic their natural, analogous immunodeterminants in binding to three monoclonal immunoglobulins

The binding of three monoclonal antigalactan immunoglobulins, IgAs X24, J539 and X44 to their natural haptens methyl beta-D-galactopyranosyl-(1-->6)-beta-D-galactopyranoside, and the corresponding tri- and tetrasaccharides, was compared to the binding of these immunoglobulins with the comparable C-linked oligosaccharide analogues 1-3. The near identity of affinities of the two sets of oligosaccharides indicated the absence of any hydrogen bond involvement by the intersaccharidic oxygen atoms in the natural immunodeterminants.     

Simulation of gas separation using partial element stage cut modeling of hollow fiber membrane modules

A mathematical model is developed to simulate a gas separation process using a hollow fiber membrane module. In particular, a new numerical technique is introduced based on flash calculation. Such analysis allows identifying the required membrane properties needed to reach module performance of interest. This model is validated for six different gas separation cases taken from literature. Then, the validated model is used to investigate the effect of O₂ and N₂ permeances on O₂ recovery and O₂ mole fraction in the permeate stream. A realistic two‐stage air enrichment process is also proposed for O₂ production using an industrial module with different fibers numbers. Moreover, this model is used to simulate a natural gas purification process using a single unit to determine the required membrane separation area and CH₄ loss. Finally, a two‐stage process is proposed to equally enhance CH₄ retentate mole fraction and decrease CH₄ loss. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1766–1777, 2018     

Coreless Fiber‐Based Whispering‐Gallery‐Mode Assisted Lasing from Colloidal Quantum Well Solids

Whispering gallery mode (WGM) resonators are shown to hold great promise to achieve high‐performance lasing using colloidal semiconductor nanocrystals (NCs) in solution phase. However, the low packing density of such colloidal gain media in the solution phase results in increased lasing thresholds and poor lasing stability in these WGM lasers. To address these issues, here optical gain in colloidal quantum wells (CQWs) is proposed and shown in the form of high‐density close‐packed solid films constructed around a coreless fiber incorporating the resulting whispering gallery modes to induce gain and waveguiding modes of the fiber to funnel and collect light. In this work, a practical method is presented to produce the first CQW‐WGM laser using an optical fiber as the WGM cavity platform operating at low thresholds of ≈188 µJ cm^?2 and ≈1.39 mJ cm^?2 under one‐ and two‐photon absorption pumped, respectively, accompanied with a record low waveguide loss coefficient of ≈7 cm^?1 and a high net modal gain coefficient of ≈485 cm^?1. The spectral characteristics of the proposed CQW‐WGM resonator are supported with a numerical model of full electromagnetic solution. This unique CQW‐WGM cavity architecture offers new opportunities to achieve simple high‐performance optical resonators for colloidal lasers.     

Groundwater Remediation through Pump-Treat-Inject Technology Using Optimum Control by Artificial Intelligence (OCAI)

Water Resources Management - Optimum Control by Artificial Intelligence (OCAI) is presented in this paper as a dynamic decision making algorithm for optimising pumpage schedule to remediate a...     

Simultaneous size and geometry optimization of steel trusses under dynamic excitations

During the past decades, the main focus of the research in steel truss optimization has been tailored towards optimal design under static loading conditions and limited work has been devoted to investigating the optimum structural design considering dynamic excitations. This study addresses the simultaneous size and geometry optimization problem of steel truss structures subjected to dynamic excitations. Using the well-known big bang-big crunch algorithm, the minimum-weight design of steel trusses is conducted under both periodic and non-periodic excitations. In the case of periodic excitations, in order to examine the effect of the exciting period of the dynamic load on the final results, the design instances are optimized under different exciting periods and the obtained results are compared. It is observed that by increasing the excitation period of the considered sinusoidal loading as well as the finite rise time of the non-periodic step force, the optimization results approach the minimum design weight obtained under the static loading counterpart. However, in the case of the studied rectangular periodic excitation, the results obtained do not approach the optimum design associated with the static loading case even for higher values of the exciting period.     

Evaluate and control service and transaction dependability of complex IoT systems

Observing and controlling the dependability of service provision of complex IoT systems is challenging. In practice, many organizations struggle to derive consumer needs related to quality and to observe and quantify the service provision in the context of the dynamic behavior of a complex distributed system. In this paper, we present an approach to define and evaluate the dependability of complex IoT systems. Our approach is an adaptation of the ISO/IEC 25040, an international standard for the evaluation process for system and software quality, which is part of the systems and software quality requirements and evaluation (SQuaRE) series. Our approach was designed and evaluated with action research in an industrial study at Robert Bosch GmbH. Based on the framework of the SQuaRE series, we integrated different elements of site reliability engineering (SRE) and combined them with distributed tracing as a promising measurement method. Our approach introduces the IoT transaction concept to reduce modeling and observation efforts while increasing operationalization to measure performance against dependability targets. Our adaption was effectively applied, consumer-centricity along different system stakeholders were enhanced, and negative consequences of organizational silos were reduced. This has improved the dependability evaluation of service provision to enable fast feedback cycles for service performance control and improvement.