Frequency response of thin film heads with longitudinal andtransverse anisotropy

A transmission surface model (TSM) that analyzes the conduction of flux by rotation and wall motion is reported. It has been used to quantitatively compare the predicted performance of thin-film heads with longitudinal and transverse magnetic anisotropy. The TSM analysis predicts that a transversely oriented type of thin-film head can be operated at much higher frequencies than a longitudinally oriented head. In addition, its group delay dispersion is much less. Finally, its susceptibility to wall pinning is an order of magnitude less. Therefore, it is concluded that the traditional aversion of head designers to the longitudinal orientation is justified for frequencies above several megahertz     

Supported Gold Nanoparticles‐Catalyzed Microwave‐Assisted Hydration of Nitriles to Amides under Base‐Free Conditions

Polystyrene‐supported gold (Au@PS) nanoparticles were synthesized by the reduction deposition approach and well characterized by UV‐visible, XRD, TEM, SAED, EDX, and XPS studies. The Au@PS was applied as catalyst for the hydration of nitriles to amides in water under microwave irradiation. Several functionalized aromatic, heterocyclic and aliphatic nitriles were found to be active for synthesis of the corresponding amides where no activation of water by base, ligand and support is needed. Easy recovery, negligible leaching and recyclability for up to eight runs are added advantages of the catalyst under water‐mediated reaction conditions.

     

Class I alleles of the bovine major histocompatibility system and their association with economic traits

A total of 179 Holstein cows from the Agriculture Canada Research Branch herd at Ottawa and 271 progeny-tested Canadian Holstein bulls were typed for 37 lymphocyte antigens. Each antigen appears to be controlled by a distinct, codominant allele of the bovine lymphocyte antigen (BoLA)-A locus, which is a class I locus of the bovine major histocompatibility system. Only 10 and 16 alleles were present in Holstein cows and bulls, respectively. The association between bovine lymphocyte antigens and economically important traits was examined in gene substitution models. Separate models were used for the cow and bull data. The substitution of the W6.1 allele for the W10 allele was associated with increased protein yield in the milk in both analyses. The results were also consistent with a previous report that the presence of the W10 allele was associated with increased fat percentage compared with some, but not all, of the other alleles. However, more research is necessary to confirm these findings and to determine the biological mechanisms underlying these associations.     

Identification of FOPDT and SOPDT process dynamics using closed loop test

In this paper, identification of stable and unstable first order, second order overdamped and underdamped process dynamics with time delay is presented. Relay with hysteresis is used to induce a limit cycle output and using this information, unknown process model parameters are estimated. State space based generalized analytical expressions are derived to achieve accurate results. To show the performance of the proposed method expressions are also derived for systems with a zero. In real time systems, measurement noise is an important issue during identification of process dynamics. A relay with hysteresis reduces the effect of measurement noise, in addition a new multiloop control strategy is proposed to recover the original limit cycle. Simulation results are included to validate the effectiveness of the proposed method.     

Genetics of growth, feed intake, and milk yield in Holstein cattle.

Heritabilities, genetic and phenotypic correlations among growth, forage consumption, and BW changes of heifers and feed consumption, BW changes, and yields of first lactation cows were estimated. Data were from 1266 Holstein progeny of 74 sires born from 1972 to 1985 at three Agriculture Canada research herds. Heavier heifers at 26 wk consumed more feed from 26 to 34 wk than smaller heifers but gained the same BW. The BW gain and feed consumption heritabilities were .17 and .23, respectively; genetic correlation was .44, and phenotypic correlation was .27. During first lactation, feed intake from 8 to 16 wk and measures of milk yield are very tightly intercorrelated both phenotypically and genetically (.78 to .98). Precalving BW gain and BW at calving were genetically uncorrelated with measures of milk yield (-.09 to +.05). Loss of BW during the first 8 wk of first lactation was moderately heritable (.29) and correlated genetically and phenotypically with measures of milk yield in early lactation (.32 to .39) and feed consumption (.26). From 8 to 16 wk, average BW changes were small and had low heritability and weak phenotypic correlations with measures of milk yield or feed intake. The BW at 26 wk and BW gain from 26 to 34 wk were very poor indicators of early first lactation milk yield. Heifer feed intake was weakly correlated phenotypically (-.07 to .16) but moderately genetically correlated (.17 to .23) with early first lactation milk yield and feed consumption.     

The steady-state kinetics of parallel reaction networks

The conventional kinetic analysis of an overall reaction (OR) is limited to a single sequential pathway of molecular steps at a time, based either on the general quasi-steady state (QSS) approach of Bodenstein, or on the much simpler but limited Langmuir–Hinshelwood–Hougen–Watson (LHHW) approach based on assuming a single rate-determining step (RDS), the remaining being quasi-equilibrated (QE). We recently described a new algebraic methodology for deriving the QSS rate expression for a reaction sequence, which allowed interpretation of the final result in an Ohm's law form, i.e., OR rate=OR motive force/OR resistance of an equivalent electric circuit, where the consecutive mechanistic steps represent resistors in series. Here, we propose a similar Ohm's law form of QSS rate for a reaction system involving parallel pathways, whose equivalent electrical circuit derives directly from the reaction route (RR) Graph of its mechanism, as proposed earlier by us. The results are exact for a reaction network with mechanistic steps linear in intermediates concentrations, while they are approximate, albeit accurate, for non-linear step kinetics. We further show how the LHHW methodology, combined with the concept of intermediate reaction might be utilized to obtain the step resistances involved. For illustration, we utilize the relatively simple examples of: (1) the gas-phase hydrogen–bromine non-catalytic reaction (non-linear kinetics), and (2) zeolite catalyzed N₂O decomposition reaction (linear kinetics). However, the approach is useful for more complex non-catalytic, catalytic and enzymatic reactions networks as well.     

Morphology Controlled Magnesium Ethoxide: Influence of Reaction Parameters and Magnesium Characteristics

Controlled reaction of magnesium with ethanol was found to produce morphological magnesium ethoxide. The scanning electron microscopy studies indicate that particles of magnesium ethoxide grow on the surface of magnesium granules and are detached from the surface as a result of shearing and collisions during the reaction. Particle characteristics of magnesium show influence on the kinetics of the reaction as well as morphological characteristics of magnesium ethoxide. Impact of other process parameter variations on the magnesium ethoxide particle characteristics is also studied. The reaction rate, agitation speed, and type of agitator show influence on the product characteristics, whereas no influence of change in reaction pressure is observed.     

Frequency planning and synthesizer architectures for multiband OFDM UWB radios

This work presents an analysis on frequency planning and synthesis for multiband (MB) orthogonal frequency-division multiplexing (OFDM) ultra-wideband (UWB) radios operating in the range of 3.1-10.6 GHz. The most important specifications for the frequency synthesizer in an MB-OFDM UWB transceiver are provided. A synthesizer architecture for an existing frequency plan is introduced along with a discussion on its performance and implementation. An alternative frequency plan and its corresponding synthesizer architecture are also proposed. It is shown how this modified frequency plan leads to a significant simplification in the synthesizer realization. The feasible performance of both synthesizer architectures is evaluated through macromodel simulations using realistic models for the building blocks. Finally, system-level simulation results showing the impact of synthesizer spurs on the bit error rate performance of an MB-OFDM UWB receiver in the presence of interferers are provided. The presented results and discussion provide valuable insight for the implementation of a 3.1-10.6-GHz UWB synthesizer.     

Aggregation in sensor networks: an energy–accuracy trade-off

Wireless ad hoc sensor networks (WASNs) are in need of the study of useful applications that will help the researchers view them as distributed physically coupled systems, a collective that estimates the physical environment, and not just energy-limited ad hoc networks. We develop this perspective using a large and interesting class of WASN applications called aggregation applications. In particular, we consider the challenging periodic aggregation problem where the WASN provides the user with periodic estimates of the environment, as opposed to simpler and previously studied snapshot aggregation problems. In periodic aggregation our approach allows the spatial–temporal correlation among values sensed at the various nodes to be exploited towards energy-efficient estimation of the aggregated value of interest. Our approach also creates a system level energy vs. accuracy knob whereby the more the estimation error that the user can tolerate, the less is the energy consumed. We present a distributed estimation algorithm that can be applied to explore the energy–accuracy subspace for a subclass of periodic aggregation problems, and present extensive simulation results that validate our approach. The resulting algorithm, apart from being more flexible in the energy–accuracy subspace and more robust, can also bring considerable energy savings for a typical accuracy requirement (fivefold decrease in energy consumption for 5% estimation error) compared to repeated snapshot aggregations.