Relay protection for lines being sleet-melted by the short-circuit method

"July 20, 1956.""Reprinted from Transactions of the American Institute of Electrical Engineers, vol. 74, December 1955.""Sleet formation on transmission lines was recognized as a serious operating problem as early as 1916 and shortly thereafter methods were devised to melt sleet. In recent years various ways have been presented for connecting lines and power sources to obtain the current necessary for sleet melting. Forced loading, phase shifting, and short circuiting are utilized extensively for this purpose. Problems of relay protection during sleet melting were not specifically presented in former papers. The purpose of this paper is to present the particular problem of protection under such conditions and to propose a means of detecting faults on lines being sleet-melted by the short-circuit method."--Page 1

Measuring equivalent circuits

"October 22, 1960.""Reprinted from Volume XXII, Proceedings of the American Power Conference.""The equivalent circuit is a familiar tool to power system engineers. Today's large interconnected power systems often are studied as electric networks in which part of the network is a simplified equivalent of the actual system. Such equivalents reduce the number of circuit elements needed to represent a part of the system which is not to be analyzed in detail, but must be accounted for as it affects the remainder. Sometimes it is found that commonly used equivalents do not correctly represent the actual network, and this is a serious problem in those studies where the size of the network compels the use of an equivalent. In this paper it will be shown that an equivalent which takes proper account of transformation ratios will give dependable results. A step-by-step procedure will be described for measuring such an equivalent without disturbing a network analyzer setup."--Page 753

Space allowance and the behaviour of captive southern hairy-nosed wombats (Lasiorhinus latifrons)

Captive southern hairy-nosed wombats (Lasiorhinus latifrons) often display indicators of substandard welfare, including aggression and stereotypical pacing. To determine if space availability influences the welfare of wombats, the behaviour of three groups of L. latifrons (n = 3) was studied in three different sized enclosures: small (S) (75.5 m2; the minimum space requirement for three wombats in Queensland, Australia), medium (M) (151 m2, twice the minimum space) and large (L) (224 m2, three times the minimum space) in a Latin Square design. Compared to wombats in larger enclosures, those in the small enclosure were observed to display more biting (S: 1.96; M: 0.42; L: 0.28, SED ± 0.56 counts / day, P = 0.01), retreat from conspecifics (S: 15.0; M: 9.9; L: 7.1 SED ± 2.66 counts / day, P = 0.03), and visual scanning (S: 52.8; M: 33.9; L: 28.8, SED ± 4.62 counts / day, P < 0.001); they also spent more time fenceline digging, which may represent attempts to escape (S: 0.78; M: 0.16; L: 0.24, SED ± 0.07 min / m / day, P < 0.0001). Those in the largest enclosure showed less self-directed grooming behaviour than those in the two smaller enclosures (S: 23.80; M: 24.08; L: 14.42, SED ± 3.22 counts / day, P = 0.02). It is concluded that small 2 enclosure size had a negative impact on the behaviour of wombat, and as a consequence, current 30 minimum space requirements for wombats in captivity should be reassessed

Differential responses of captive southern hairy-nosed wombats (Lasiorhinus latifrons) to the presence of faeces from different species and male and female conspecifics

The southern hairy-nosed wombat (Lasiorhinus latifrons) appears to use scent marking, including defaecation, for social communication in the wild. This premise assumes that the receiver wombat is able to distinguish between faeces from different sources. To examine this theory, four types of faeces (male wombat, female wombat, dingo and a plastic control) were placed into the enclosures of 12 captive wombats. Behaviour, inter-individual distance and enclosure use were recorded during the period of placement, as well as the period before and the period after. When faeces were present, the wombats used concealed locations more often than other periods (mean %: pre-treatment: 71.3, treatment: 75.6, post-treatment: 72.7; P < 0.05). During the same period they also reduced grazing (mean min/period: pre- treatment: 15.8, treatment: 6.9, post- treatment: 13.1; P = 0.0002) and walking 2 activity (mean min/period: pre- treatment: 85.2, treatment: 66.9, post- treatment: 78.2; P = 0.01), indicating an increased perception of risk. Wombats approached the dingo faeces 5.6 times per treatment period, which was greater than for the control (3.0; P = 0.004) or female wombat faeces (3.7; P = 0.049). They also avoided other wombats most when male wombat faeces were present (8.3 retreats/period) compared to the control (4.5; P = 0.02), or female wombat (4.3; P = 0.01). There was a residual effect of increased wombat avoidance the period after presentation of dingo faeces (9.6; P ≤ 0.05). It is concluded that the southern hairy-nosed wombat can differentiate between faeces from different species and sex of conspecifics, and that predator faeces and those from male conspecifics increase wombat avoidance behaviour either during or after presentation

Strength Reduction in Electrical and Elastic Networks

Particular aspects of problems ranging from dielectric breakdown to metal insu- lator transition can be studied using electrical o elastic networks. We present an expression for the mean breakdown strength of such networks.First, we intro- duce a method to evaluate the redistribution of current due to the removal of a finite number of elements from a hyper-cubic network of conducatances.It is used to determine the reduction of breakdown strength due to a fracture of size $\kappa$.Numerical analysis is used to show that the analogous reduction due to random removal of elements from electrical and elastic networks follow a similar form.One possible application, namely the use of bone density as a diagnostic tools for osteorosporosis,is discussed.Comment: one compressed file includes: 9 PostScrpt figures and a text fil

Chemical derivation to enhance the chemical/oxidative stability of resorcinol-formaldehyde (R-F) resin

Tank wastes at Hanford and SRS contain highly alkaline supernate solutions of conc. Na, K nitrates with large amounts of {sup 137}Cs. It is desirable to remove and concentrate the highly radioactive fraction for vitrification. One candidate ion exchange material for removing the radiocesium is R-F resin. This report summarizes studies into synthesis and characterization of 4-derivatized R-F resins prepared in pursuit of more chemically/oxidatively robust resin. 85% 4-fluororesorcinol/15% phenol formaldehyde resin appears to have good stability in alkaline solution, although there may be some nucleophilic displacement reaction during synthesis; further studies are needed

Clinical and pathologic characteristics of focal segmental glomerulosclerosis pathologic variants

Histologic variants of idiopathic focal segmental glomerulosclerosis (FSGS) may have prognostic value. A recent working classification system has distinguished five FSGS variants. We evaluated a cohort of adult patients with biopsy-proven FSGS diagnosed between March 1982 and July 2001 to determine if subtypes were associated with renal outcome. Renal biopsies were reviewed by two pathologists. Demographic and clinical data were obtained from charts. Outcomes were partial and complete remission of the nephrotic syndrome, and renal failure. The frequency of FSGS variants was: 3% cellular (=6), 11% collapsing (=22), 17% tip lesion (=34), 26% perihilar (=52), and 42% not otherwise specified (NOS) (=83). Collapsing FSGS affected younger and more often black patients. Black race was uncommon in tip variant. Collapsing and tip variants had higher proteinuria and lower serum albumin than perihilar and NOS variants. Better renal function and less severe tubulointerstitial injury were observed in patients with tip variant. These patients were more likely to receive steroids and more often achieved complete remission (50%). After a median follow-up of 1.8 years, 23% of patients were on dialysis and 28% had renal failure. Collapsing FSGS had worse 1-year (74%) and 3-year (33%) renal survival compared to other variants (overall cohort renal survival at 1 and 3 years: 86 and 67%). Different histologic variants of FSGS have substantial differences in clinical features at the time of biopsy diagnosis and substantial differences in renal outcomes

Combining series elastic actuation and magneto-rheological damping for the control of agile locomotion

All-terrain robot locomotion is an active topic of research. Search and rescue maneuvers and exploratory missions could benefit from robots with the abilities of real animals. However, technological barriers exist to ultimately achieving the actuation system, which is able to meet the exigent requirements of these robots. This paper describes the locomotioncontrol of a leg prototype, designed and developed to make a quadruped walk dynamically while exhibiting compliant interaction with the environment. The actuation system of the leg is based on the hybrid use of series elasticity and magneto-rheological dampers, which provide variable compliance for natural-looking motion and improved interaction with the ground. The locomotioncontrol architecture has been proposed to exploit natural leg dynamics in order to improve energy efficiency. Results show that the controller achieves a significant reduction in energy consumption during the leg swing phase thanks to the exploitation of inherent leg dynamics. Added to this, experiments with the real leg prototype show that the combined use of series elasticity and magneto-rheologicaldamping at the knee provide a 20 % reduction in the energy wasted in braking the knee during its extension in the leg stance phase

Professionalism, Golf Coaching and a Master of Science Degree: A commentary

As a point of reference I congratulate Simon Jenkins on tackling the issue of professionalism in coaching. As he points out coaching is not a profession, but this does not mean that coaching would not benefit from going through a professionalization process. As things stand I find that the stimulus article unpacks some critically important issues of professionalism, broadly within the context of golf coaching. However, I am not sure enough is made of understanding what professional (golf) coaching actually is nor how the development of a professional golf coach can be facilitated by a Master of Science Degree (M.Sc.). I will focus my commentary on these two issues