Steeping of Wheat at Various Temperatures – Effects on Physicochemical Characteristics of the Starch

Wheat prior to isolation of starch by wet-milling and a commercial starch sample were steeped at various temperatures (10° to 50°C.) in water. An extended steeping (72 h) increased the gelatinization temperature. In starches steeped for a limited period (24 h) a slight loss of amylose and decrease in solubility occurred as steeping temperatures increased. Water-binding capacities, however, remained virtually identical, decreased somewhat with higher steeping temperatures. The data show that time rather than temperature of steeping is critical in preserving native properties of wheat starch granules.     

Rapid thermal annealing of rare earth implanted ZnO epitaxial layers

Zinc oxide epilayers grown by metal organic vapour phase epitaxy on (0 0 0 1) sapphire substrates were doped with Praseodymium and Europium by ion implantation. The as-implanted samples were either annealed in air for 20 min in a tube furnace or rapid thermal annealing (RTA) was performed, for 2 min, in a nitrogen atmosphere. The samples were characterized by Rutherford Backscattering Spectrometry/Channelling and photoluminescence. The presented results indicate that in the as-implanted samples the majority of the rare earth (RE) ions are incorporated into substitutional Zn-sites. Furnace annealing at 1000 °C recovers the crystal quality of the samples but leads to an out-diffusion of the RE. RTA suppresses diffusion but lattice damage is not fully recovered at 1000 °C. More importantly, during RTA the RE ions are driven from the substitutional site and are now found mainly on random interstitial sites and no optical activation could be achieved.     

Complexities of operating in foreign property markets

The world is on the brink of an unprecedented growth-related ecological crisis that could well undermine prospects for global civilization. Nevertheless, the global community seems ‘in flight from thinking’ about the implications of the threat and unwilling to contemplate the policy remedies necessary to change the course of history. Biological and cultural factors combine to inhibit clear understanding and effective corrective action. Mainstream ‘solutions’ – hybrid cars, green buildings, smart growth, the new urbanism – are thus rooted in denial and delusional. These approaches do not address the fundamental problem of ‘overshoot’, but rather attempt to maintain the growth-bound status quo through efficiency gains and related technological ‘fixes’. This might actually worsen the situation. Achieving sustainability requires that such marginal reform give way to a complete rethink of society's relationship with nature. Developed societies need a new, more adaptive cultural mythology. The building sector arguably has greater material leverage in reducing the human ecological footprint than any other major industrial sector. Acceptance of the guidelines developed in this paper would revolutionize the industry and reorient it geographically. The question is: does the industry have the intellectual courage and practical momentum to assume a lead role in the sustainability campaign?

Le monde est au bord d'une crise écologique sans précédent, liée à la croissance, qui pourrait bien saper les perspectives d'avenir de la civilisation mondiale. Néanmoins, la communauté mondiale semble se refuser à penser aux implications de cette menace et ne pas se résoudre à envisager les remèdes politiques nécessaires pour modifier le cours de l'histoire. Les facteurs biologiques et culturels se conjuguent pour entraver une compréhension claire et la prise de mesures correctives efficaces. C'est la dénégation et l'illusion qui se trouvent ainsi être à l'origine des « solutions » dominantes – voitures hybrides, bâtiments verts, croissance intelligente, le nouvel urbanisme. Ces approches ne traitent pas du problème fondamental du « dépassement écologique » [des capacités productives de la Terre], mais tentent de maintenir le statu quo lié à la croissance grâce à des gains de rendement et aux « palliatifs » technologiques qui leur sont liés. Cela pourrait en fait aggraver la situation. Parvenir à un environnement durable nécessite qu'une réforme aussi minime cède le pas à une relation de la société à la nature totalement repensée. Les sociétés développées ont besoin d'une nouvelle mythologie culturelle, dotée d'une plus grande capacité d'adaptation. L'on peut soutenir que, s'agissant de réduire l'empreinte écologique de l'humanité, le secteur du bâtiment a une influence matérielle plus grande qu'aucun autre secteur industriel important. L'acceptation des directives développées dans cet article révolutionnerait l'industrie et la réorienterait géographiquement. La question est: l'industrie a-t-elle le courage intellectuel et le dynamisme pratique pour assumer un rôle leader dans la campagne en faveur d'un environnement durable?

Mots clés: comportement, cadre bâti, changement climatique, comportement cognitif, narrations culturelles, dépassement écologique, développement durable     

Inverter nonlinearity effects in high-frequency signal-injection-based sensorless control methods

An analysis of pulsewidth-modulation inverter nonlinearities influencing high-frequency carrier-signal voltage injection for saliency-tracking-based rotor/flux position estimation is presented in this paper. Distortion of the injected carrier voltage caused by the nonlinear behavior of the inverter has been reported to cause errors in the estimated rotor/flux position. Though a number of techniques have been developed to compensate for inverter nonlinearities, they have not been proven to be effective when a high-frequency low-magnitude voltage needs to be generated. Both the origins of the distortion as well as the requirements for compensation methods to be effective when producing such high-frequency voltages will be established in this paper.     

Impairments of manual tracking performance during spaceflight: more converging evidence from a 20-day space mission

Studies of human performance during spaceflight have consistently revealed degradations of manual tracking performance in space. The present investigation analysed these performance decrements in more detail by applying frequency-response analyses of tracking performance. It was hypothesized that tracking impairments result from two factors: at an early adaptation phase in space they primarily reflect effects of microgravity on human visuo-motor processes, whereas later into the mission they are also caused by impairments of attentional processes induced by cumulative workload and fatigue. In order to investigate this hypothesis, performance of one cosmonaut in a first-order unstable tracking task was repeatedly assessed before, during and after a 20-day space mission. Single-case statistical analyses revealed the following effects: tracking performance declined at the first assessment in space and in two later inflight sessions compared to pre-flight baseline. Whereas the early tracking decrement was mainly due to an increase of the effective time-delay during tracking and accompanied by only minor changes of mood or workload, one of the later inflight impairments was due to an increase of effective time-delay, a decreased tracking gain, and an increase of tracking remnant, and both were associated with considerably higher workload ratings. This pattern of effects supports the two-factor hypothesis.     

A rotor lamination design for surface permanent magnet retention athigh speeds

A major problem in the design and manufacturing of surface mounted permanent magnet machines is reliably holding the permanent magnets in place at high speeds. This paper evaluates a unique rotor lamination design for a high pole number, permanent magnet alternator. This buried magnet design, which is capable of reliably holding the permanent magnets in place at high speeds, offers both easier and cheaper assembly when compared with the methods currently used in surface mounted permanent magnet machines. Finite element analysis is used to compare the buried magnet design with equivalent surface mounted designs and shows that the performance of the alternator is not significantly affected by the iron over the magnets. Experimental results from a prototype alternator further corroborate the FEA and show that the design is capable of operating at high speeds with no other means of magnet retention. In addition, an improvement in the buried magnet design which can reduce the lamination complexity is suggested and examined     

Flux-based active filter controller

This paper presents a synchronous frame flux-based control method for a parallel active filter application. The flux-based controller directly implements the inverter switchings in the synchronous reference frame by a hysteresis rule-based carrier-less pulse-width modulation (PWM) strategy to achieve high current bandwidth. This paper addresses the issues and impact on parallel active filtering requirements for utility interface of commonly used harmonic front-ends. The synchronous frame flux-based controller provides additional insights for harmonic current compensation requirements. Simulation results provide the validation of the flux-based active filter controller to meet IEEE Standard 519 recommended harmonic standards for large rated nonlinear loads under balanced and unbalanced supply conditions