Adaptive non-linear speed control of induction motors

In this paper we present two adaptive non-linear speed control algorithms for induction motors. They employ input-output linearization techniques for the motor model in the stator fixed reference frame. The first control algorithm directly tracks speed and rotor flux. The second is designed using torque and rotor flux tracking and is extended for speed control. A key point is that this algorithm ensures exact current limitation in the known parameter case. The adaptation based on Lyapunov design can cope with rotor and stator resistance variations. Significant simulations using sampled controllers are presented emphasizing adaptation and current limitation effects.     

Attachment style and relationship satisfaction: Test of a self-disclosure explanation.

[Correction Notice: An erratum for this article was reported in Vol 30(2) of Canadian Journal of Behavioural Science/Revue canadienne des sciences du comportement (see record 2009-19933-001). Some figures were inadvertently omitted in two tables. The correct tables are provided in the erratum.] Explored a self-disclosure explanation for why those with a secure attachment style report greater relationship satisfaction than those with insecure attachment styles. Ss were 99 17–36 yr old students who were in ongoing relationships and who had different attachment styles. Ss were compared in terms of the self-disclosures they directed toward their partner vs a stranger, using questionnaire and behavioural measures. Behavioural self-disclosure was assessed by having Ss give talks on different topics, while anticipating that either their current partner or an opposite-sex stranger would later hear it. Results show that Ss with a secure attachment style disclosed more intimately to their partners than to strangers; whereas those with insecure attachment styles did not. Moreover, secures disclosed more personal facts to their partners than to strangers and were also perceived as more comfortable while self-disclosing to partners than to strangers. Finally, support for the hypothesis that self-disclosure mediates the relation between attachment style and relationship satisfaction was found on one component of self-disclosure, facilitative disclosure, a component which included both reported self-disclosure to one's partner and self-rated ability to elicit disclosure from others. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chronic dissection of the thoracic aorta in a patient with tuberculous pleuro-pericarditis

The production of mycotoxins by Alternaria alternata in cellulosic ceiling tiles was examined with thin-layer chromatography and high-performance liquid chromatography procedures. Alternariol and alternariol monomethyl ether were found in ceiling tile extracts, whereas extracts of control rice cultures of all three isolates produced these mycotoxins plus altenuene and altertoxin I. Extensive fungal growth and mycotoxin production occurred in the ceiling tiles at relative humidities of 84-89% and 97%.     

Ethnicity and perceived discrimination in Toronto: Another look at the personal/group discrimination discrepancy.

Perceptions of personal and group discrimination in 5 domains (jobs, pay, loans, promotions, and clubs) were investigated via telephone interviews with 902 respondents from different ethnic groups in Toronto. The reported analyses concern 6 ethnic groups, representing "visible," racial minorities (Blacks, Chinese, and South Asians) as well as White minorities (Italians, Jews, and Portuguese). The personal/group discrimination discrepancy (i.e., perceiving greater discrimination toward one's group than oneself personally) was observed to varying extent across all domains and ethnic groups, though with some exceptions. Visible minorities perceived greater discrimination toward their group than did White minorities, especially in the economic domains of jobs, pay, and promotions. Among visible minorities, Black respondents perceived higher levels of group and personal discrimination than most other ethnic groups across domains, followed in turn by Chinese and South Asian respondents. By contrast, White minority group members perceived considerably less group or personal discrimination than members of visible minorities, except for Jewish respondents who reported greater group discrimination in joining clubs than any other ethnic group. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Symptom subtypes in persons institutionalized with schizophrenia: Comparison of demographics, outcome and functional skills.

Using a formula based on the concept by N. C. Andreasen (see record 1982-29376-001) and N. C. Andreasen and S. Olsen (see record 1982-30452-001) of classifying subtypes into positive, negative, and mixed schizophrenia, 312 persons institutionalized with Diagnostic and Statistical Manual of Mental Disorders (DSM-III) schizophrenia were retrospectively examined. 59 Ss were classified into the positive symptom subtype, 33 into the negative symptom subtype, and 220 into the mixed symptom subtype. Symptom subtypes were compared on traditional demographic and outcome indicators, as well as on a dimension critical to rehabilitation (i.e., measures of degree of assistance necessary to perform functional skills). No significant differences were found among the subtypes on demographic items and traditional indicators of outcome such as level of vocational functioning or independent living. However, on measures of degree of assistance necessary to perform functional skills, significant differences were found among the symptom subtypes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The leaching of copper from sulphur activated chalcopyrite with cupric sulphate in nitrile-water mixtures

If chalcopyrite is roasted with sulphur at 400–450°C pyrite and idaite or bornite are produced. Bornite plus pyrite are also prepared by roasting a 1:1 mixture of chalcopyrite and covellite. These copper-iron sulphides were leached with acidified aqueous cupric sulphate solutions containing acetonitrile or hydracrylonitrile and the results are compared with leaching with acidified cupric chloride in brine. The nitrile route has the advantage of a less corrosive sulphate medium for subsequent copper recovery processes.Bornite appears to be the most attractive product from the roasting of sulphur and chalcopyrite because much of its copper can be readily leached. Iron reports to the solution only in the latter stages of extraction. Up to 80% of the copper in this bornite is leached with CuSO₄/RCN/H₂O at 60°C. Copper is recovered from the resulting cuprous sulphate solution by electrowinning with inert anode. The products are copper cathodes and cupric sulphate, which is recycled. The leach residue may be used to reactivate further chalcopyrite or is leached of its copper by established routes.     

Electrically pumped circular-grating surface-emitting DBR laser onInGaAs strained single-quantum-well structure

The authors demonstrate the fabrication and room temperature operation of an electrically pumped circular-grating surface-emitting distributed-Bragg-reflector laser. An InGaAs/GaAs single quantum well (SQW) graded-index separate confinement heterostructure (GRINSCH) structure was grown by one-step molecular beam epitaxy (MBE). Circular gratings were defined by focused ion beam lithography. The lasing wavelength was 942 nm, and the threshold current was 280 mA. This is the first demonstration of these lasers with no epitaxial regrowth     

Transmission of step functions by loop antennas

The characteristics of pulses received by an antenna when it is placed in the field of another antenna excited with step functions are studied. The transmitting and receiving antennas are rectangular loops loaded at their midpoint with a resistance to avoid ringing. The received pulses computed on the basis of an elementary radiation integral compare well with measurements.