Radiation dose from dissolved radon in potable waters of the Bangalore environment,South India

Potable waters from various locations of the Bangalore environment were investigated for their ²²²Rn concentrations by the emanometry method. About 94 groundwater (borewell) samples were analysed for ²²²Rn concentrations and found to vary in the range 5.3–283.4 Bq L^?1 with a mean value of 87 Bq L^?1. Frequency distribution showed the ²²²Rn concentration in a large number of samples in the range of 0–50 Bq L^?1. From the measured concentrations, the effective doses (lung and stomach) for the population of the region were estimated. The effective dose was found to vary from 42.6 to 2280.2 µSv y^?1 with a mean value 702.5 µSv y^?1. The effect of boiling of water showed a drastic reduction in the ²²²Rn concentration. The results of the present investigation are systematically analysed, compared with the literature values and discussed.     

A novel ratiometric fluorescent Yb3+ sensor based on a N′-(1-oxoacenaphthylen-2(1H)-ylidene)furan-2-carbohydrazide as a suitable fluorophore

N′-(1-oxoacenaphthylen-2(1H)-ylidene)furan-2-carbohydrazide (L) was synthesized for the first time and used as a ratiometric fluorescent chemosensor for high selective recognition of Yb³⁺ ions in acetonitrile (MeCN) solution. The L–Yb³⁺ complexation quench the fluorescence of L at 420 nm and induces new fluorescent enhancement at 516 nm. Due to the formation of a 2:1 metal ligand complex in acetonitrile solution, the red shift of fluorescent emission spectrum occurred. The sensor shows a linear response toward Yb³⁺ ion concentration in the range of 3.3 × 10^? 7 M to 1.0 × 10^? 4 M with detection limit of 1.2 × 10^? 7 M. The fluorescent probe exhibits high selectivity for Yb³⁺ ion over the other common mono-, di-, and trivalent cations.     

Cooling Performance and Indoor Air Quality Characteristics of an Earth Air Tunnel Cooled Building

Most of the modern air-conditioned buildings have a low fresh air supply to reduce energy consumption. This results in a poor indoor air quality (IAQ) and a 30–200% higher sick building syndrome than that of a naturally ventilated building. Alternatively, energy-efficient and eco-friendly earth air tunnel system (EATS) provides a good IAQ because of the sufficient fresh air supply. This paper presents the cooling performance and IAQ characteristics of a sparsely occupied building supported with an EATS. The building was monitored for the concentration of fine and coarse particulate matter (PM), carbon dioxide (CO₂) and carbon monoxide (CO), temperature distribution and relative humidity (RH) in September and October 2012. The average PM₁₀, PM_2.5 and PM₁ concentrations were 6.77, 6.11 and 3.17 μg/m³ respectively when the EATS was operated. These are marginally higher compared to that when the EATS was not operated. The average indoor CO₂ level, air temperature and RH were 418 ppm, 26.5 °C and 58.2% respectively when the EATS was operated. The diurnal indoor CO₂ trend relates well with photosynthetic and anthropogenic activities in and around the building. The CO₂ and PM concentrations correlate well with indoor air temperature and RH with a time lag.     

Magneto-transport and Magnetic Susceptibility of SmFeAsO1−x F x (x=0.0 and 0.20)

We report superconductivity in the SmFeAsO_1?x F _x for the x=0.2 system being synthesized using the single step solid state reaction route. Rietveld analysis of room temperature X-ray diffraction (XRD) data shows the studied samples, SmFeAsO_1?x F _x with x=0.0 and x=0.2, are crystallized in a single phase tetragonal structure with space group P4/nmm. The resistivity measurement shows superconductivity for the x=0.20 sample with T _c (onset) ～51.7 K. The upper critical field, [H _c2(0)] is estimated ～3770 kOe by Ginzburg–Landau (GL) theory. Broadening of superconducting transition in magnetotransport is studied through thermally activated flux flow in an applied field up to 130 kOe. The flux flow activation energy (U/k _B ) is estimated ～1215 K for 1 kOe field. Magnetic measurements exhibited bulk superconductivity with lower critical field (H _c1) of ～1.2 kOe at 2 K. In the normal state, the paramagnetic nature of compound confirms no trace of magnetic impurity, which orders ferromagnetically. AC susceptibility measurements have been carried out for SmFeAsO_0.80F_0.20 sample at various amplitude and frequencies of applied AC drive field. The intergranular critical current density (J _c ) is estimated. Specific heat [C _p (T)] measurement showed an anomaly at around 140 K due to the SDW ordering of Fe, followed by another peak at 5 K corresponding to the antiferromagnetic (AFM) ordering of Sm⁺³ ions in the SmFeAsO compound. Interestingly, the change in entropy (marked by the C _p transition height) at 5 K for Sm⁺³ AFM ordering is heavily reduced in the case of the superconducting SmFeAsO_0.80F_0.20 sample.     

Predictions of crack propagation using a variational multiscale approach and its application to fracture in laminated fiber reinforced composites

Predictions of crack propagation is a valuable resource for ensuring structural integrity and damage tolerance of aerospace structures. Towards that end, a variational multiscale approach to predict mixed mode in-plane cohesive crack propagation is presented here. To demonstrate applicability and to provide validation of the finite element based predictive methodology, a comparative study of the numerical results with the corresponding experimental observations of crack propagation in laminated fiber reinforced composite panels is presented.     

Studies on electrodeposition and corrosion behaviour of a Ni–W–Co amorphous alloy

A ternary alloy Ni–W–Co was electrodeposited and operational parameters in relation to its corrosion resistance and deposition efficiency were optimized. A 2² full factorial design was successfully employed for experimental design analysis of the results. By means of response surface analysis, the statistical model identified the following operating conditions for obtaining corrosion resistant alloy: 60 mA/cm² current density, 70 °C temperature, 20 rpm cathode rotation and 8.0 pH. The alloy was deposited at 36% current efficiency, with an average composition of 70% Ni, 8% Co, 22% W and traces of boron and with E _corr −0.508 V and R _p 4.56 × 10⁴ Ohm. The deposit obtained under these conditions had an amorphous character and showed good adherence, high corrosion resistance and presence of nodules on its surface. Electrochemical corrosion tests verified that the Ni–W–Co alloy had better corrosion resistance than similarly electrodeposited Co–W amorphous alloy.     

A modelling framework to support design of complex engineering systems in early design stages

Production, assembly or logistic systems exist in widespread domains. It is agreed that more than 50% of life-cycle performance, costs and environmental impacts of such systems are due to those decisions that are made in their early design stages (Reich, Res Eng Design 28(4):411–419, https://doi.org/10.1007/s00163-017-0270-7, 2017). However, the large scale and multi-disciplinary essence of such systems make their design considerably challenging. Most of the design approaches follow a sequential approach such that the design in each lower level is finalized/frozen before proceeding to the next level. However, such approaches do not properly address the interaction between different design disciplines which may later lead to design inconsistencies. Therefore, this paper aimed to propose a modelling framework that allows having an integrated approach in the early design stages of such systems. To this end, first the framework prescribed developing an executable meta-architecture that can embody all the design requirements. Second, the framework describes the interconnections between the meta-architecture with certain supporting algorithms and optimization models. This allows generating and simulating different design alternatives and observing the impact of different design decisions on system integrated performance. Therefore, the proposed framework with its providing outcomes can be used to support the decision making in early design stages of such systems. The framework is applied in a real case study from the warehousing domain, which serves to show the practical application of the proposed framework.     

Removal of phenols from aqueous solutions by emulsion liquid membranes

The present study deals with the extraction of phenols from aqueous solutions by using the emulsion liquid membranes technique. Besides phenol, two derivatives of phenol, i.e., tyrosol (2-(4-hydroxyphenyl)ethanol) and p-coumaric acid (4-hydroxycinnamic acid), which are typical components of the effluents produced in olive oil plants, were selected as the target solutes. The effect of the composition of the organic phase on the removal of solutes was examined. The influence of pH of feed phase on the extraction of tyrosol and p-coumaric was tested for the membrane with Cyanex 923 as an extractant. The use of 2% Cyanex 923 allowed obtaining a very high extraction of phenols (97-99%) in 5-6 min of contact time for either single solute solutions or for their mixtures. The removal efficiency of phenol and p-coumaric acid attained equivalent values by using the system with 2% isodecanol, but the removal rate of tyrosol was found greatly reduced. The extraction of tyrosol and p-coumaric acid from their binary mixture was also analysed for different operating conditions like the volume ratio of feed phase to stripping phase (sodium hydroxide), the temperature and the initial concentration of solute in the feed phase.