Discrimination between Bacillus and Alicyclobacillus Isolates in Apple Juice by Fourier Transform Infrared Spectroscopy and Multivariate Analysis

Alicyclobacillus is a causative agent of spoilage in pasteurized and heat‐treated apple juice products. Differentiating between this genus and the closely related Bacillus is crucially important. In this study, Fourier transform infrared spectroscopy (FT‐IR) was used to identify and discriminate between 4 Alicyclobacillus strains and 4 Bacillus isolates inoculated individually into apple juice. Loading plots over the range of 1350 and 1700 cm^?1 reflected the most distinctive biochemical features of Bacillus and Alicyclobacillus. Multivariate statistical methods (for example, principal component analysis and soft independent modeling of class analogy) were used to analyze the spectral data. Distinctive separation of spectral samples was observed. This study demonstrates that FT‐IR spectroscopy in combination with multivariate analysis could serve as a rapid and effective tool for fruit juice industry to differentiate between Bacillus and Alicyclobacillus and to distinguish between species belonging to these 2 genera.     

Method to Measure the Force to Pull and to Break Pin Bones of Fish

A texture measurement device was modified to measure the force required to pull pin bones from King salmon (Oncorhynchus tshawytscha), snapper (Pagrus auratus), and kahawai (Arripis trutta). Pulled bones were also subjected to tension to measure the breaking force. For all fish, the pulling force depended on the size of the fish, and on the length of the pin bone (P < 0.05). In general, larger fish required greater pulling force to remove pin bones. For example, fresh small salmon (about 1500 g whole) required 600 g on average to pull pin bones, and large fish (about 3700 g whole) required 850 g. Longer bones required greater pulling force. The breaking force followed the same trend. In general, the breaking force was greater than the pulling force. This allows the removal of the bones without breaking them. There was no statistically significant (P > 0.05) difference between the forces (both pulling and breaking) from fresh and frozen/thawed samples, although in general frozen/thawed samples required less force to pull. With the quantification of pulling and breaking forces for pin bones, it is possible to design and build better, “more intelligent” pin bone removal equipment.     

Network coding for MPR-based flooding in ad hoc wireless networks under mobility conditions

We propose a novel distributed coding scheme for broadcast over mobile ad hoc networks. In this scheme, we combine MPR technique with network coding. Only multipoint relay (MPR) nodes perform coding using a rateless code. Rather than waiting for a large number of encoded packets to be received before MPR nodes could decode and resend coded packets, we design a new degree distribution that enables the nodes to start decoding even when small number of encoded packets are received. Thus, we decrease the delay introduced at the intermediate nodes. The main advantage of using a rateless code for encoding instead of using a random linear combination of the previously received packets is to reduce significantly the encoding and decoding complexities. We provide a performance evaluation using a simulation to demonstrate the efficiency of our code even under mobility condition.     

Modeling the Power Output of Piezoelectric Energy Harvesters

Design of experiments and multiphysics analyses were used to develop a parametric model for a d ₃₃-based cantilever. The analysis revealed that the most significant parameters influencing the resonant frequency are the supporting layer thickness, piezoelectric layer thickness, and cantilever length. On the other hand, the most important factors affecting the charge output are the piezoelectric thickness and the interdigitated electrode dimensions. The accuracy of the developed model was confirmed and showed less than 1% estimation error compared with a commercial simulation package. To estimate the power delivered to a load, the electric current output from the piezoelectric generator was calculated. A circuit model was built and used to estimate the power delivered to a load, which compared favorably to experimentally published power data on actual cantilevers of similar dimensions.     

Growth and production of a short rotation coppice culture of poplar. II. Clonal and year-to-year differences in leaf and petiole characteristics and stand leaf area index

Twelve different poplar (Populus) clones, belonging to different species and interspecific hybrids were studied during the first and second growing seasons of the second rotation of a high density coppice culture. Leaf size, leaf area, leaf nitrogen and specific leaf area (SLA) were examined at two different canopy levels, together with petiole length and petiole diameter. Leaves in the upper canopy layer were larger, heavier and had a lower SLA. They also had longer and thicker petioles, as well as a higher nitrogen concentration per unit dry weight than lower canopy leaves. Significant clonal variation was observed in leaf and petiole characteristics in both growing seasons. Leaf area index (LAI), scaled-up from allometric relationships, showed significant clonal variation in the two growing seasons, and increased for all clones in the second growing season. LAI increment was related to a significantly increased diameter of all shoots. Our study demonstrates (i) that light significantly affects leaf and petiolar characteristics, and nitrogen concentrations of foliage elements, and (ii) that year-to-year differences in foliar characteristics are related to stand aging rather than to increased shading due to larger LAI.     

An analytical model for silicon MIS/IL solar cells to optimize cell parameters through thermal annealing

A model has been developed which simulates the effect of cell parameters in order to optimize them by controlling the fabrication conditions, namely, annealing time and annealing temperature. Calculation of the efficiency as a function of surface states density D_it, positive fixed oxide charge density Q_f and mobile charge density Q_m, that depend on anealing conditions are carried out. A compromise between D_it and Q_m for different anealing temperatures for high performance cells has been investigated.     

Measurement of the parameters of nanometer films by optical and microwave methods

It is demonstrated that the thickness and the electrical characteristics of thin insulator and metal films in layered structures can be determined from the reflection and transmission spectra of optical and microwave radiation interacting with these films. Measurements of the refractive index of SnO₂ films in the range of thicknesses 40 nm to 2.8 μm and the electrical conductivity of Cr films deposited on ceramic substrates are reported.     

Mobile ad hoc network broadcasting: A multi‐criteria approach

Nodes in a computer network often require a copy of a message to be delivered to every node in the network. The network layer can provide such a service, referred to as network‐wide broadcast routing or simply ‘broadcasting’. Broadcasting has many applications, including its role as a service to many routing protocols. In a mobile ad hoc network (MANET), simplistic broadcast schemes (such as flooding) inundate the network with redundancy, contention, collision, and unnecessary use of energy resources. This can prevent broadcasts from achieving their primary objective of maximizing delivery ratio, while also considering secondary objectives, such as balancing energy resources or reducing the network's burden on congested or busy nodes. As a solution, we propose multiple‐criteria broadcasting (MCB). In MCB, the source of each broadcast specifies the importance assigned to broadcast objectives. Network nodes use these priorities, along with local and neighbor knowledge of distributed factors, to broadcast in accordance with the objective priorities attributed to the message. Using ns2, the performance of MCB is evaluated and compared to that of other broadcast protocols. To present knowledge, MCB constitutes the first reconfigurable, multi‐objective approach to broadcasting. Copyright © 2010 John Wiley & Sons, Ltd.     

Influence of Ion Induced Local Coulomb Field and Polarity on Charge Generation and Efficiency in Poly(3‐Hexylthiophene)‐Based Solid‐State Dye‐Sensitized Solar Cells

Dye‐sensitized solar cells (DSSC) are a realistic option for converting light to electrical energy. Hybrid architectures offer a vast materials library for device optimization, including a variety of metal oxides, organic and inorganic sensitizers, molecular, polymeric and electrolytic hole‐transporter materials. In order to further improve the efficiency of solid‐state dye‐sensitized solar cells, recent attention has focused on using light absorbing polymers such as poly(3‐hexylthiophene) (P3HT), to replace the more commonly used “transparent” 2,2′,7,7′‐tetrakis‐(N,N‐di‐p‐methoxyphenyl‐amine)9,9′spiro‐bifluorene (spiro‐OMeTAD), in order to enhance the light absorption within thin films. As is the case with spiro‐OMeTAD based solid‐state DSSC, the P3HT‐based devices improve significantly with the addition of lithium bis(trifluoromethylsulfonyl)imide salts (Li‐TFSI), although the precise role of these additives has not yet been clarified in solid‐state DSCs. Here, we present a thorough study on the effect of Li‐TFSI in P3HT based solid‐state DSSC incorporating an indolene‐based organic sensitizer termed D102. Employing ultrafast transient absorption and cw‐emission spectroscopy together with electronic measurements, we demonstrate a fine tuning of the energetic landscape of the active cell components by the local Coulomb field induced by the ions. This increases the charge transfer nature of the excited state on the dye, significantly accelerating electron injection into the TiO₂. We demonstrate that this ionic influence on the excited state energy is the primary reason for enhanced charge generation with the addition of ionic additives. The deepening of the relative position of the TiO₂ conduction band, which has previously been thought to be the cause for enhanced charge generation in dye sensitized solar cells with the addition of lithium salts, appears to be of minor importance in this system.