Evaluating system behavior through Dynamic Master Logic Diagram (DMLD) modeling

In this paper, the Dynamic Master Logic Diagram (DMLD) is introduced for representing full-scale time-dependent behavior and uncertain behavior of complex physical systems. Conceptually, the DMLD allows one to decompose a complex system hierarchically to model and to represent: (1) partial success/failure of the system, (2) full-scale logical, physical and fuzzy connectivity relations, (3) probabilistic, resolutional or linguistic uncertainty, (4) multiple-state system dynamics, and (5) floating threshold and transition effects. To demonstrate the technique, examples of using DMLD to model, to diagnose and to control dynamic behavior of a system are presented. A DMLD-based expert system building tool, called Dynamic Reliability Expert System (DREXs), is introduced to automate the DMLD modeling process.     

Enhanced chemical stability,chromatic properties and regeneration of betalains in Rivina humilis L. berry juice

Betalains are hydrophilic colorants containing chromophore betalamic acid. Owing to poor stability, its usage is limited to low acidic short shelf-life, and frozen foods. In this report, effect of metals (inorganic Se⁴⁺, Zn²⁺, and Cu²⁺) on stability of betalains in Rivina humilis L. berry juice (RBJ) was studied in presence of 10 and 40 μg metal/mL with/without ascorbic acid (AA; 0.25 and 0.5 g/100 mL). Se bleached RBJ betacyanins mildly, whereas Zn, and Cu bleached the pigments significantly. AA protected the pigments from metal-induced bleaching, and stabilizing effect of 0.25 g AA/100 mL was higher (P < 0.05) than 0.5 g AA/100 mL. AA (0.25 g/100 mL) + Se (40 μg/mL) enhanced (five-fold) the half-life time of betacyanins. RBJ betacyanins degraded up to 95% and 96% on treatment for 36 min at 90 °C and storage for 48 days at 25 °C, respectively, whereas only 15% pigment was lost on storage (5 °C, 90 days). AA (0.25 g/100 mL) + Se (40 μg/mL) regenerated the pigments on storage at 5 °C after thermal degradation. Color values of AA (0.25 g/100 mL) + Se (40 μg/mL) containing samples indicated an orange tinge, whereas other samples turned brown yellow after thermal treatment.     

Magnesium substitution in brushite cements

The use of magnesium-doped ceramics has been described to modify brushite cements and improve their biological behavior. However, few studies have analyzed the efficiency of this approach to induce magnesium substitution in brushite crystals. Mg-doped ceramics composed of Mg-substituted β-TCP, stanfieldite and/or farringtonite were reacted with primary monocalcium phosphate (MCP) in the presence of water. The cement setting reaction has resulted in the formation of brushite and newberyite within the cement matrix. Interestingly, the combination of SAED and EDX analyses of single crystal has indicated the occurrence of magnesium substitution within brushite crystals. Moreover, the effect of magnesium ions on the structure, and mechanical and setting properties of the new cements was characterized as well as the release of Ca^2 + and Mg^2 + ions. Further research would enhance the efficiency of the system to incorporate larger amounts of magnesium ions within brushite crystals.     

Numerical investigation of fluid flow and heat transfer around a solid circular cylinder utilizing nanofluid

In this study, flow-field and heat transfer through a copper–water nanofluid around circular cylinder has been numerically investigated. Governing equations containing continuity, N–S equation and energy equation have been developed in polar coordinate system. The equations have been numerically solved using a finite volume method over a staggered grid system. SIMPLE algorithm has been applied for solving the pressure linked equations. Reynolds and Peclet numbers (based on the cylinder diameter and the velocity of free stream) are within the range of 1 to 40. Furthermore, volume fraction of nanoparticles (φ) varies within the range of 0 to 0.05. Effective thermal conductivity and effective viscosity of nanofluid have been estimated by Hamilton–Crosser and Brinkman models, respectively. The effect of volume fraction of nanoparticles on the fluid flow and heat transfer characteristics are investigated. It is found that the vorticity, pressure coefficient, recirculation length are increased by the addition of nanoparticles into clear fluid. Moreover, the local and mean Nusselt numbers are enhanced due to adding nanoparticles into base fluid.     

A low power tunable Gm–C filter based on double CMOS inverters in 0.35?μm

In this article, an inverter based transconductor using double CMOS pair is proposed for implementation of a second order lowpass G_m?CC Filter. The proposed operational transconductance amplifier (OTA) and biquad filter are designed using standard 0.35???m CMOS technology. Simulation results demonstrate the central frequency tunability from 10?kHz to 2.8?MHz which is suitable for the wireless specifications of Bluetooth (650?kHz), CDMA 2000 (700?kHz) and Wideband CDMA (2.2?MHz) applications. The power consumption of the filter is 445?nW and 178???W at 10?kHz and 2.8?MHz from 3.3?V supply voltage, respectively. The active area occupied by the designed filter on the silicon is 215?×?720???m². The proposed approach guarantees the upper bound on THD to be ?40?dB for 300?mVpp signal swing. Employing the double CMOS pair in the inverters causes PSRR to reach 68.6?dB which is higher than similar works.     

A theoretical discussion on the foundation of Stone??s blind source separation

This paper discusses the theoretical foundation of Stone’s BSS (Stone in Neural Comput 13:1559–1574, 2001; Stone in Independent Component Analysis: A Tutorial Introduction, A Bradford Book, London, 2004), and it proposes a novel BSS approach based on second-order statistics of the responses of two different linear filters to source signals. The proposed approach which includes Stone’s BSS as a special case helps us to understand how generalized eigenvalue decomposition (GEVD) concludes separating vectors in Stone’s BSS. It obtains the separating vectors by simultaneous diagonalization of covariance matrices of two different linear filters responses to the mixtures. The two employed linear filters are selected dependent on source signals structures under the assumption that they have different responses to source signals. Here, two FIR filters with coefficients selected in an opposite probabilistic way have been suggested for the proposed BSS. The proposed BSS method has been compared with Stone’s BSS, SOBI and AMUSE over speech and image mixtures in different noise levels.     

Physicochemical Properties of Mammalian Gelatin in Relation to Membrane Process Requirement

In any of the membrane process application, understanding of the characteristics of the feed solution is essential in order to achieve desired level of separation performance. In this study, in an effort to substitute evaporation with membrane processes partially, experiments were carried out to investigate the physicochemical properties of gelatins, namely, molecular weight distribution, pH, viscosity, isoelectric point, and gel strength, which are, of foremost, important parameters in the characterization of gelatin. Two different mammalian gelatins, i.e. from bovine (type B) and porcine (type A) sources, were used in this study. The pH was significantly varied for all gelatins in the vicinity of 4.75–5.51 (±0.01). Experimental result revealed that both sources of mammalian gelatin contained components of different molecular weights with wide distribution ranging from 10 to 400 kDa. Analysis of the molecular weight distribution result also showed strong correlation between average molecular weight and gel strength of gelatin. The isoelectric points of gelatins from bovine were 4.60 ± 0.08 to 5.25 ± 0.43 and porcine gelatins were in the range of 7–9.3, which agreed well with the results obtained from other researchers. The high bloom strength mammalian gelatins were also significantly more viscous and thus, had a higher melting point.     

Ohmic‐assisted hydrodistillation of essential oils from Zataria multiflora Boiss (Shirazi thyme)

Ohmic‐assisted hydrodistillation (OAHD) is a combination of ohmic heating and distillation, and could be considered as a novel method for the extraction of essential oils. Major problems with traditional methods are long extraction time and lower purity of the extract. In this study, OAHD was applied as an economic and green technology for the extraction of essential oils from Zataria multiflora Boiss. (Shirazi thyme) aerial parts and the results were compared to those obtained from hydrodistillation (HD) as a conventional method. The results showed that OAHD method had the extraction time of 32.21 ± 2.59 min while this value was about 57.21 ± 2.33 min for hydrodistillation (HD). Scanning electron micrographs of thyme leaves showed a sudden eruption of essential oil glands and their surrounding area for OAHD samples. GC–MS analysis indicated that both methods of OAHD and HD can extract the same compounds.     

Technical appraisal of solar home systems in Bangladesh: A field investigation

Solar Home System (SHS) based rural electrification has experienced a considerable growth in Bangladesh since the start of the Rural Electrification and Renewable Energy Development Project (REREDP) in 2003. The initial target of 50,000 SHS installations in off-grid areas was achieved within 2.5 years, 3 years ahead of schedule. After achieving a revised target of 200,000 SHSs, ahead of schedule in early 2009, a new target of 1 million SHS installations by 2012 was set. The installation of about 0.5 million systems by March 2010 indicates that the current target may well be achieved before the deadline. The size of the SHS market and its impact on the regeneration of the rural economy make it necessary to investigate the quality and reliability of the installed SHSs, if the continued success of the initiative is to be maintained. This paper reports on the findings from a field-based technical appraisal of SHS installations in Bangladesh. Sixty geographically dispersed installation sites were visited. Physical characteristics of the SHSs and their system components were tested to ascertain compliance with and deviations from the approved specifications. Despite the overwhelming success of the REREDP project, the study revealed various shortcomings. Notable among these are: incompatible and sub-optimal component configurations, faulty installations and a lack of effective quality assurance mechanism. The findings are contextualized and the ways to address the identified shortcomings are discussed.     

Swing angle estimation for anti-sway overhead crane control using load cell

Overhead crane movement results in suspended load sway, which may cause dangers and damages. Common anti-sway methods are based on swing angle information. This paper presents a novel method that uses load cell sensors for swing angle estimation. According to our proposed method, a damping signal is generated and added to the speed reference in order to suppress the suspended load sway. Conventional methods of swing angle estimation are based on measurement by camera vision, acceleration, or some other type of sensor. Compared to conventional methods, the proposed method based on load cell is simpler to build and less sensitive to ambient conditions. The effectiveness of the method is verified by computer simulation.