Wall Decay Coefficient Estimation in a Real-Life Drinking Water Distribution Network

Water Resources Management - Injection of chlorine as a disinfectant and the correct prediction of the residual amount in water distribution networks are key points and important principles in the...     

Simultaneous determination of pyruvate and acetate levels in xanthan biopolymer by infrared spectroscopy: effect of spectral pre-processing for solid-state analysis

A rapid, direct, and reagent-free procedure based on solid-state Fourier transform infrared spectroscopy (FT-IR) coupled with partial least squares (PLS) data analysis has been developed for simultaneous determination of pyruvate and acetate levels in a microbial xanthan biopolymer. The influences of various spectral pre-processing procedures were studied in order to eliminate effects caused by sample preparation. It was determined that the combination of first derivative and orthogonal signal correction pre-processing contributes to a significant increase in the predictive performance of PLS-1 regression models. By employing the wavenumber region 1320–1350 cm⁻¹ for pyruvate determination and 1500–1600 cm⁻¹ for acetate determination, the root mean square error of cross-validation (RMSECV) for pyruvate and acetate contents were obtained 0.13% and 0.29% w/w, respectively. Results of the proposed procedure for different real samples and those obtained by their reference methods were compared.     

Optimization and implementation of multimode piezoelectric shuntdamping systems

Piezoelectric transducer (PZT) patches can be attached to a structure in order to reduce vibration. The PZT patches essentially convert vibrational mechanical energy into electrical energy. The electrical energy can be dissipated via an electrical impedance. Currently, impedance designs require experimental tuning of resistive circuit elements to provide optimal performance. A systematic method is presented for determining the resistance values by minimizing the H₂ norm of the damped system. After the design process, shunt circuits are normally implemented using discrete resistors, virtual inductors and Riordian gyrators. The difficulty in constructing the shunt circuits and achieving reasonable performance has been an ongoing and unaddressed problem in shunt damping. A new approach to implementing piezoelectric shunt circuits is presented. A synthetic impedance, consisting of a voltage controlled current source and a digital signal processor system, is used to synthesize the terminal impedance of a shunt network. A two-mode shunt circuit is designed and implemented for an experimental simply supported beam. The second and third structural modes of the beam are reduced in magnitude by 22 and 18 dB     

Tribological Challenges in Micromechanical Systems

Despite much progress in surface micromachining technology, adhesion, friction and wear remain key issues, severely limiting the realization and reliability of many microelectromechanical systems (MEMS) devices. In this article, we focus on the use of molecularly thin organic films as release and anti-stiction coatings for MEMS. The various classes of organic films explored for MEMS are reviewed here, followed by a discussion of the current limitations and areas for improvements for this coating technology.     

Precision current and charge amplifiers for driving highly capacitive piezoelectric loads

Piezoelectric transducers are known to be highly capacitive loads that exhibit less hysteresis when driven with current or charge rather than voltage. Compliance feedback current and charge amplifiers are introduced. A secondary output voltage feedback loop is employed to prevent DC charging of capacitive loads and to compensate for any voltage or current offsets in the driver circuit. Low frequency bandwidths in the milliHertz range can be achieved.     

Community’s evaluation of organizational legitimacy: Formation and reconsideration

With the aim of delving into the legitimacy formation mechanisms used by communities to make judgements about project organizations, this research studied the local community and surrounding environment of four oil extraction projects located in three developing countries. The results of the cross-case analysis suggest that communities' negative perceptions from government and media can influence their judgement of organizational behaviour. Additionally, this research proposes that local communities' anticipation of the consequences of protesting against the organization can make them decide not to take any action. According to institutional theory, when community individuals arrive at a legitimacy verdict about an organization, their future perceptions will mainly be influenced by this decision rather than conscious consideration of the conditions. Accordingly, this research recommends that organizations aiming to recover their reputation need to adopt compensation activities with a substantial influence on the improvement of conditions. It is only in such conditions that communities will consciously evaluate organizational legitimacy. Trivial changes in organizational behaviour will only result in adding new evidences in support of the illegitimacy of organizations.     

Turkish diasporic responses to the Taksim Square protests: Legacy media and social media uses in Belgium,the Netherlands and Germany

Based on an offline and online survey of 967 people of Turkish origin living in these countries, we test how legacy and social media have influenced the participation of the members of the Turkish diaspora in Belgium, Germany and the Netherlands in the mid-2013 protests in Turkey’s social movement referred to as Gezi Park. This study also investigates how living in Europe can influence the behavior and attitudes of the sampled individuals from the Turkish Diaspora of Germany, Belgium and Netherlands during the period when the Gezi Park demonstration took place. Our results make it clear that social media were used by those who supported the protest movement, while those who opposed the protest movement primarily used or followed traditional sources of media, including Turkish and European television. Furthermore, supporters amongst the diaspora for the Gezi-protests were primarily active in accruing social capital through bonding and social networking among those who belong to the Turkish diaspora under the guise of the Gezi Park protests. Finally, a significant number of the supporters of the protests in the three countries took part in several different means of supporting the movement, including: disseminating awareness about the Gezi protests through social media, engaging in meetings, and in some cases, even severing contact with friends and acquaintances who did not share their support for the protest movement.     

An Improved Estimation of the Angstrom–Prescott Radiation Coefficients for the FAO56 Penman–Monteith Evapotranspiration Method

The FAO56 Penman–Monteith (FAO56-PM) method is known as the standard method for estimating reference evapotranspiration (ET₀) in a variety of climate types. Global solar radiation (R_s) is one of the essential inputs of this model, which is usually estimated from the Angstrom–Prescott (AP) method. The major drawback of the FAO56 pre-defined AP coefficients application is that the AP coefficients might need local calibration, to estimate ET₀ accurately. The aim of this study is to compare the effect of the FAO56 pre-defined AP coefficients (i.e. a and b) and the locally calibrated ones, on estimating daily ET₀ in 15 sites over Iran. Using long-term (1980–2007) experimental global solar radiation data (R_s), new locally calibrated (a) and (b) coefficients are suggested and new ET₀ values are determined accordingly. It was found that the range of the calibrated AP coefficients (a, b) are climate dependent and locally different from those of recommended by the FAO56-PM method. Estimated ET₀ at daily scale, improved up to 72.7 % when the calibrated AP coefficients were applied instead of FAO56 pre-defined AP coefficients. Based on the results, applying the FAO56 pre-defined AP coefficients (i.e. a?=?0.25 and b?=?0.50) in northern subtropical-humid and southern hot climates caused larger ET₀ errors. By contrast, the least ET₀ errors were found in cool arid and cool semi-arid inland climates, locating about 1,330 above sea level. The correlations between the calibrated AP coefficients and geographical factors are also discussed in this research.     

A new cerium (III) ion selective electrode based on 2,9-dihydroxy-1,10-diphenoxy-4,7-dithia decane, a novel synthetic ligand

In the present study, a novel electrode based on 2,9-dihydroxy-1,10-diphenoxy-4,7-dithiadecane (DHDPDTD) that is selective to cerium (III) cations was evaluated electrochemically, and a Nerenstian slope (19.3 ± 1 mV decade⁻¹) over a concentration range of 1.0 × 10⁻⁸–1.0 × 10⁻¹ M and a detection limit of 2.1 × 10⁻⁹ M were observed. The proposed electrochemical sensor displayed a rapid response time of 10 s, improved selectivity towards Ce (III) cations in the presence of alkali, alkaline earth, transition and heavy metal cations, and could be used in a pH range of 5.0–8.0. Additionally, the proposed sensor was used as an indicator in the potentiometric titration of fluoride and the determination of F⁻ ions in real samples.