Paving Stone Research Articles

Frictional behaviour of a polyurethane rubber sliding on concrete: Analysis of a slip and fall accident

A slip and fall accident which caused a severe ankle injury occurred when a 37 year old, 140 lb female stepped from the forecourt of a shopping centre onto the first of a series of paving stones laid across a bed of bushes. The first paving stone was 0.168 m below the level of the forecourt and not horizontal. Careful friction measurements using the accident shoes showed that the friction coefficient between a heel and the paving stone was 0.35 “ 0.05 when testing started. A transient effect caused the coefficient to increase to 0.55 - 0.05 during the first few tests. The effect of the paving stone slope was to reduce the effective friction coefficient by 0.12 so that the effective coefficient experienced by the accident victim at the time of the accident was 0.23 - 0.05. This is comparable to the friction coefficient experienced by the driver of a vehicle who applies the brakes while driving on a horizontal sheet of ice. In a lawsuit filed by the accident victim's attorney it is claimed that the manageme...

Moving from Coming Out to Intimacy

Abstract Straight adolescents go through a long period of training for intimacy. The developmental steps are well-worn-beginning with mixed gender group activities and school contacts, moving to dating and going steady. A lesbian or gay adolescent, particularly if he or she is aware of being “different,” generally does not have such a road map to follow and heterosexual models of dating are ill equipped to manage the special hurdles that a gay or lesbian individual must surmount to gain social/sexual intimacy. A therapist can pave the path to intimacy by effective therapeutic intervention early in the first phases of moving out of the stage of gay identity formation into gay socialization. The first paving stone can be laid by educating the patient about the process. A variety of myths about one's desirability and suitability for a gay relationship grow out of the fact that the availability of suitable partners is severely curtailed by minority status and closeting. These myths routinely stigmatize lesbia...

The effect of a lactic acid bacterial inoculant on maize silage

Maize silage is an important forage in South Africa and it is often made without the use of any additives. Very little information on the fermentation dynamics of maize silage under local conditions is presently available. The aim of this study was to determine if the adding of a lactic acid bacterial inoculant to maize at ensiling will improve the fermentation dynamics of maize silage and to determine the effect of the inoculant on the intake and growth of lambs. Maize was harvested at the hard dough stage with a Feraboli 930 silage chopper and ensiled with or without the addition of a lactic acid bacterial inoculant in 18 laboratory silos for each treatment. Silos were 1.5 l glass jars, equipped with a special lid with springs which enables gas release only. The fermentation dynamics during ensiling was determined by opening three silos on day 1, 2, 4, 10 and 95 of ensiling. The adding of the inoculant to maize at ensiling did not result in a more rapid drop in pH and higher levels of lactic acid. For the intake and growth study maize was ensiled in thirty 210 l drums lined with a plastic bags for each treatment. The material was compacted, the bags were closed and a concrete paving stone (20 kg) was placed on top of the bag. The intake and growth of South African Mutton Merino lambs fed inoculated and untreated maize silage was determined. 2 groups of 14 lambs weighing 26.4±1.9 and 26.4±1.6 kg were randomly allocated to the control and the inoculant treatment, respectively. The average daily gain of lambs fed a diet consisting of either 60% control or inoculated maize silage over a growth period of 60 days was 239±26 and 255±44 g day −1, respectively. The feed conversion efficiencies were 4.94 and 4.93 kg DM feed kg −1 live weight gain for lambs fed the control and inoculated silage diets, respectively. Although the laboratory study showed very little effect of adding a lactic acid bacterial inoculant to maize at ensiling, lambs tended to consume more of the inoculated silage.