Hard Floor Research Articles

Rough handling, soil temperature, and root development in outplanted Sitka spruce and Douglas-fir

Sealed bags containing forty 2-year-old Sitka spruce (Piceasitchensis (Bong.) Carr.) transplants were dropped 1–15 times from a height of 3 m onto a hard floor. A single drop reduced root growth potential of the plants as measured by a 10-day test, although after 18 days' growth the effect was no longer detectable. Dropping the bags 5 or 15 times severely decreased root growth potential even in the 18-day test. The 15-drop treatment significantly depressed 1-year survival of samples planted in the nursery. Sitka spruce and Douglas-fir (Pseudotsugamenziesii fMirb.) Franco.) transplants dropped 10 times, together with control plants, were placed in root observation boxes with an air temperature of 8 °C and a soil temperature of 4, 8, 12, or 16 °C. At 4 °C soil temperature, little or no root growth was observed in either species. At the higher temperatures the total numbers of new roots formed in 10 days and the number of new roots greater than 1 cm in length formed in 18 days were generally greater in Sitka spruce than Douglas-fir. In both species, root growth was sharply reduced by the mechanical shock treatment. Dropping the trees also depressed mycorrhizal development and resulted in a significant lowering of predawn water potential in Douglas-fir.

Keratin proteins in human oral mucosa

We have examined the keratin proteins in normal human oral mucosa from 6 different regions including hard palate, buccal mucosa, tongue, gingiva and floor of the mouth. Urea-dithiothreitol extracts of EDTA separated epithelia were analysed by SDS-PAGE and immunoblotting. Eight samples from each region were investigated and showed very little individual variation in the keratin profile on Coomasie Blue-stained gels. The keratinizing hard palate and gingiva expressed identical patterns and resembled the pattern of epidermis from the flank region. The normally non-keratinizing buccal mucosa and the mucosa of the floor of the mouth expressed polypeptides distinctly different from those of the keratinizing epithelia and lacked the high molecular weight keratins. The dorsal surface of the tongue and the commissure region showed a pattern intermediate between keratinizing and non-keratinizing epithelia. The greater sensitivity of the immunoblotting technique revealed that the non-keratinizing epithelia synthesized one of the high molecular polypeptides and that the tongue produced all the bands found in keratinizing epithelia, but in very small quantities. There are, thus, distinct differences in the keratin expression of oral epithelia which are related to the pattern of keratinization assessed histologically.

Arthroscopic Assessment and Treatment of Dancers' Knee Injuries.

In brief: The author saw 16 dancers with a history of dance-related knee injuries that had defied conservative treatment. Arthroscopic examination revealed 15 meniscal tears and four cases of chondromalacia patellae. The meniscal tears were treated by partial arthroscopic meniscectomy and the chondromalacia patellae by shaving, drilling, and debridement of the patella. After surgery the results were rated by means of a physical examination and a patient questionnaire. The results were generally excellent, with 13 of the 16 dancers returning to a preoperative level of dance activity. However, the author stresses the importance of preventing injury by using correct dance technique, wearing knee pads during practice, and avoiding excessively hard floor surfaces.

The Tambourine Lady

NOW I LAY ME DOWN TO SLEEP ... there would be new shoes in the morning. New shoes and an old dress white as new. White and starched as angel wings and hair perfect as heat and grease could press it to her skull. There would be hands to hold as she rose up from the curb onto the one step which took you from Homewood Avenue, which was nowhere, to the door of the church wide as heaven. Hands she'd need to steady her across the threshold, the tall, red doors, from cement to the velvet cushioned wobble of God's purple carpet. Always unsteady as she passed to His world. Like that first step off the moving stairs in Kaufmann 's Department Store downtown when you think you might be falling and the hard cold floor rushing up to crack your knees and elbows. At the door of the church her mother's hand, the hands of Miss Goings in her soft white gloves to help her through. She might lose her breath, her heart would stutter but she wouldn't fall. Old Miss Goings in her starched nurse's uniform. Her hand was like petting a rabbit. Miz Goings smelling like Johnson's Baby Powder who'd say, My sweet girl or Bless you, Darling daughter or just Sugar so the wide doors did not swallow you or slam in your face. New shoes pinched your feet sometimes. Too big, too small, too much money, too ugly for anybody. The white ladies who sold them would stick any old thing on your feet and smile. But sometimes when her feet were in new shoes she couldn't feel them at all. She floated, unsure whether or not the shoes were still down there, stepping when she stepped, wondering if she'd lost them, brand new and costing money nobody has, lost them a long time ago because that's how they felt. Like the shoes didn't belong to her when they were new and shiny because she wasn't new and shiny like them. She was nobody, nowhere, dream ing about a little girl in new shoes she'd never own, shoes that wouldn't be down there if she looked to the end of the white socks at the ends

Measurement of strain rate behaviour in complete mandibular dentures

A major cause of fracture in complete lower dentures is due to the denture falling onto a hard floor. Impact failure has never been investigated in complete dentures and in a material which is strain rate dependent, a knowledge of the maximum strain and strain rate at failure is essential if laboratory tests are to evaluate materials in a realistic manner. The work described includes brittle lacquer studies to establish the strain pattern which occurs when a denture is dropped fm a height of 1 metre. This was used to orientate strain gauges and experimental dentures were then hit by a specially constructed ram driven at known velocities by a spring, whilst the strain was recorded on a storage oscilloscope. Photographs of the stored wave form were then used to establish the results at ram velocies equal to that of a denture falling 1 metre. Maximum strains were achieved of 11 × 10 3 microstrain and strain rates of 1.04 × 10 3 microstrain/ms. Laboratory impact machines for testing denture base materials should therefore be designed to achieve these figures.

The relationship in the response of ovaries of superovulated heifers

Pregnant Holstein–Friesian (HF) heifers were transported from central Europe (defined as temperate conditions) to north-eastern Brazil (defined as tropical, semiarid conditions). They were kept in open-sided pens with a hard floor, a roof for shade and sprinkled with water for 10 min every hour if ambient temperature exceeded 30°C. Their diet was balanced to meet nutritional requirements and they were fed twice daily. Control animals were randomly chosen first and second lactation animals located on a farm 25 km away and receiving similar management. Imported animals were superovulated in 1996 (n=63) and 1997 (n=96), compared to 38 and 45 cows in the control herd. The variates recorded were: the interval post-partum to first oestrus; changes in ovarian size and activity; responses to superovulation; and, embryo quality.The average daily milk yields of the imported cows were 20.0 and 23.3 l in 1996 and 1997, respectively compared to 22.1 l throughout the experiment for cows in the control herd.The post-partum anoestrus interval in the imported cows were 112.1±30.5 days in 1996 compared to 55.0±18.0, 48.2±12.0 and 42.6±10.7 days in 1997 for control cows. The size and functionality of the ovaries was lowest for the imported animals in 1996 but did not differ between other group–year combinations. These animals also had a lower superovulatory response in 1996 than control cows in terms of the number of ovulations (6.4±4.3 versus 13.6±5.9, P<0.05) and good quality embryos (1.2±0.9 versus 4.4±2.1, P<0.05). The two groups of cows did not differ in respect of these characters in the second year of the study.The imported cows had lower reproductive efficiency and responses to superovulation in their first year in their new environment. A period of approximately 1.5 years is required for full adaptation.

Mercury Vapor Exposure in the Dental Office—Does Carpeting Make a Difference?

Data from mercury vapor surveys of 1.064 rooms in dental offices show no difference in ambient breathing zone concentrations of mercury vapor between offices with hard floors and offices with carpets. Laboratory experiments show that either type of floor can be successfully treated to practically eliminate its contribution to employee mercury exposures. The most effective approach to controlling mercury vapor exposures is to prevent contamination of the air and working environment through the disciplined practice of effective mercury hygiene. We believe the dental profession should stress an exposure limit of 0.02 mg/cu m or less as a standard of good practice.

Performance of hemi-anechoic Rooms

Because the constructive and destructive interference between a source and its image formed by the ground plane obscures the conformity of the sound field with the inverse square law, we have used a carousel method to evaluate the performance of hemi-anechoic rooms (i.e., free field rooms with acoustically hard floors). Using the carousel method, the spatial variation of the SPL in hemi-anechoic rooms having the overall shape of a rectangular parallelepiped periodically fluctuates around a mean value. The amplitude of these spatial fluctuations is a function of the room wall acoustic properties and decreases as the carousel radius decreases and as the frequency and bandwidth increases. We take the rms value of these spatial fluctuations as a measure of the room performance. We conclude that the performance of hemi-anechoic rooms having thick, fibrous glass blankets on the walls and ceiling compares favorably with anechoic rooms having wedge-lined walls and ceiling. Furthermore, since the walls and ceiling of rooms having fibrous glass blankets can be represented by a partially absorbing plane of known surface impedance, the performance of such rooms can be predicted.

Where I Live

This world has a tall roof. Wind is its wall. This world has a hard floor? many have fallen. If I ever forgave you we could meet here; or we could start walking some morning and never come back. Our friends would forget us; without us the hawthorn hedge would smother the rose; the sound of our street would lull, but be almost the same. Dogs could inherit this town we once wanted to come back to again?

Computer‐controlled experiment for scaled indoor measurements of traffic noise propagation effects

A series of acoustic measurements have been completed, simulating traffic noise produced by automobiles and trucks. In order to provide controlled tests, scaled measurements were conducted in a large gymnasium using a 5:1 scale factor. An automated, computer‐controlled system was specially designed to complete the large number of measurements required. A remote‐controlled cart simulated the traffic vehicles. A digital computer controlled the tests, collected and processed the raw data for quicklook analysis, and recorded both the raw and processed results for detailed postrun analysis. Measurements were made simulating uniform terrain with the hard floor for infinite impedance terrain and covering the floor with carpet for finite impedance terrain. Sound field variations due to sound‐impeding barriers of various shapes were also measured. This paper presents an overview of the measurements conducted and the data collection‐processing systems, and illustrates some of the measured results. [Work jointly supported by the NCHRP and FHWA.]

Les sediments superficiels des Approches occidentales de la Manche

The part of the continental terrace stretching along a 250 km axis from the Western English Channel to the shelf edge is covered by a blanket of sediments ranging from fine sands to pebbles. Three terrigenous fringing areas are of Pleistocene origin: the periarmorican pebbly strip and the quartzitic sands located off Devon—Cornwall and near the shelf edge. The remainder is composed preponderantly of bioclastic sands, deposited through the Holocene and up to the present. The tidal currents, occasionally augmented by storm-induced oscillatory water movements, exert the main control on the distribution of the sediments. An evolutionary model starting from the Würmian low sea-level environment is proposed. It takes into account the specificity of the great sand-bank area in the southwest which was submerged whilst, onshore, subaerial and periglacial conditions led to the deposition of pebbles and, to a minor extent, of detritic sands south of England. The progression of the Holocene transgression triggered the productivity of the epifauna on the submerged, hard floor zones and modified the hydrodynamic conditions which, in turn, reacted upon the distribution of the organogenic debris. The velocity of the tidal currents is maximum (over 2 knots) around Brittany, keeping the pebbly area generally free of sedimentation of smaller particles. The distribution pattern of the bioclastic fraction (concerning mainly Bryozoa) enables one to consider a general axial transportation trending towards the SW which is corroborated by previous studies dealing with small-scale sedimentary features.

Some effects of environmental stress on the electret condenser microphone

Over the past several years improvements have been made in the basic design of electret condenser microphones. A thinner ,and tougher diaphragm and a new design of the diaphragm support have produced an exceptional resistance to mechanical and thermal shocks, During a mechanical shock test five microphones were let fall from a height of 2 m (6 ft, 7 in.) onto a hard floor (concrete covered with thin plastic tile). The sensitivities of these microphones changed between +0.1 and +1.4 dB. Two microphones were exposed to thermal shock by suddenly changing the ambient temperature from −40 to +25°C. Their sensitivity shifted +0.7 and +1.2 dB, respectively, and they were immediately covered by frost. Within 30 min they recovered to within 0.3 dB of initial sensitivity. These microphones have a temperature coefficient of sensitivity typically less than +0.01 dB/°C at frequencies below 2 kHz, and it remains less than +0.015 dB/°C through the frequency range up to 20 kHz. The inherent immunity to high humidity of electret microphones is further improved by using a better insulator material.

Experimental studies on environmental contamination with infected blood during haemodialysis.

To assess the relative importance of different postulated modes of spread of hepatitis B in dialysis units, blood charged with various tracer organisms was used in simulated haemodialysis runs in four laboratories, and the resulting contamination of equipment and environment was measured semi-quantitatively. Some airborne spread of the tracer organism occurred when tubing containing contaminated blood was needled as the "patient" went on and came off the dialyser. Virtually no small airborne particles could be demonstrated however in simulated emergencies in which a blood line was disconnected, or even when bottles of blood were dropped on to a hard floor from a height of 2 metres. Bacillus globigii spores from contaminated blood leaked in small numbers into the dialysing fluid through apparently intact coils. T3 phage, with a particle size of the same order as hepatitis B virus, passed in small quantities through the membrane of a Kiil dialyser from blood to dialysing fluid and also in the reverse direction when added to the header tank. A number of other dialysers were also permeable to phage. Visual assessment of the appropriate moment for inserting the venous line into the "patient" at the onset of dialysis was shown to be unreliable, as the displaced fluid from the end of the venous line was already contaminated before it contained visible red blood cells. Considerable contamination of exposed surfaces and of the buttons on the proportionating unit cabinet occurred. Minor visible splashing of blood was a common-place of the laboratory experiments and was shown to be also a common event during routine haemodialysis in two of the dialysis units taking part in the studies.

Avian oral pigmentation.

Inspections were made of the oral mucosae in three Lutino parakeets, six Bee Bee parrots, and four Ama­ zons (two Amazona aestiva, or blue-fronted, and two Amazona ochrocephala or yellow-fronte d). Sections of hard palate, tongue, and floor of the mouth were excised from the anesthetized birds, and duplicate specimens placed in 10% buffered neutral formalin. A portion of each specimen was processed for routine paraffin em­ bedding, while the other was treated for dopa enzyme reaction before processing and embedding. The paraffin blocks were cut at 6 microns, and the

Organogenic gradients in the study of neritic deposits of biological origin: The example of the western English Channel

Fixed epifauna lives on “hard floors” which are washed by strong currents; on the other hand, the endofauna needs loose sedimentary sea floors, which means that the currents must be weak enough to allow sedimentation. Analysis of neritic organogenic sediments with respect to the proportions of detritus formed from fixed epifauna and from the endofauna permits the determination of certain characteristics of the sedimentary environment.

Mechanical Shocks Produced on Hearing-Aid Transducers

When a hearing aid is dropped accidentally, damage may occur to the external plastic housing, any of the circuit elements contained within it. lead wires, transducers, etc. The shock amplitudes to which microphones and receivers (earphones) may be subjected in representative eyeglass and behind-the-ear hearing aids under such conditions have been measured by a simulated drop test. The peak shock amplitudes in selected orientations were unexpectedly high, ranging up to 7000 G in one hearing aid for the equivalent of a 30-in. drop on a hard floor. The lower peak acceleration for a 30-in. drop in the same orientation was the order of 100 G. The median value of peak shock amplitude for hearing aids measured was 2500 G for these conditions. Time durations of the impact pulses ranged from 96 to 335 μsec at the half-amplitude points for the simulated 30-in. drop. Representative data are given for simulated 15- and 30-in. drops from several impact directions. It is apparent from these observations that provision of satisfactory protection for shock in dropped instruments, while maintaining a degree of vibration isolation, presents a severe design problem to the hearing-aid engineer. A miniature ceramic accelerometer, which duplicated in weight and external geometry the transducer in the hearing aid, was mounted in the same way as the replaced transducer. The hearing aids were struck from 3 directions related to the position and orientation of the transducer in the hearing aid by a pendulum having mass appreciably greater than the hearing aid.

Motor co-ordination of pecking fowls

The skill of cocks and hens at pecking grain has been examined with a turntable apparatus and on hard and soft stationary floors. Each type of test gave results which could easily be repeated. There was considerable individuality in performance, which remained constant over a few weeks. In the course of a year the relative performance of 3 hens changed somewhat. Cautious trimming of the beak disrupted performance for a number of days. There was an inverse correlation between the area of the comb and both the rate and accuracy of pecking. Rate of pecking and accuracy were positively correlated. It is concluded that when a group of fowls is given a limited amount of grain, varying skill, as well as the social hierarchy, will make an important contribution to differences in consumption between individual birds.

Polybutadienes of Controlled Cis, Trans and Vinyl Structures

Abstract The physical properties of polybutadiene vulcanizates have been measured as a function of polymer microstructure. Although the over-all properties of any one polybutadiene are determined by the relative ratio of cis, trans and vinyl units in the polymer chain, marked changes in physical properties do not occur until a relatively pure configuration is approached or unless the raw polymer displays crystallinity. Thus, polybutadienes containing more than 85 per cent cis, trans or vinyl units are characteristically different from each other and the differences are accentuated as the isomeric forms approach 100 per cent of a given configuration. Polybutadiene of 95 per cent cis configuration displays very low heat generation and high resilience (equaling natural rubber in these properties) and excellent abrasion resistance. trans-Polybutadiene (90 per cent), a crystalline plastic in the raw state, becomes rubbery after vulcanization. Gum vulcanizates possess high tensile strength, and tread stocks display high modulus and tensile strength, high hardness and fair hysteresis properties. Vulcanizates of amorphous 94 per cent vinyl polybutadiene are characterized by fair tensile properties, low hysteresis, and poor low temperature properties. Crystalline syndiotactic polybutadiene, 70 per cent vinly, displays much higher gum and tread tensile strengths than its amorphous counterpart. Amorphous polybutadienes containing less than 70–80 per cent of any one configuration are generally similar in most properties, and resemble emulsion polybutadiene in many respects. The wide range of properties of the various polybutadienes makes them suitable for many applications. cis-Polybutadiene is an excellent tire rubber, which has given as much as 40 per cent greater abrasion resistance than natural rubber in passenger tire tests. Heavy duty 10:00 × 20 truck tires fabricated with a 1:1 blend of cis-polybutadiene and natural rubber in the treads have given slightly better abrasion ratings and lower running temperatures than control tires fabricated entirely from natural rubber. Amorphous 80 per cent cis-polybutadiene has been found to possess exceptionally good low temperature properties, far superior to present arctic-type unsaturated elastomers, trans-Polybutadienes by virtue of their high modulus, high tensile strength, and high hardness could be utilized in the preparation of hard rubber goods, floor tiles, and shoe soles. While none of these polybutadienes is yet available commercially, their unusual properties and potential applicability in many areas should lead to their manufacture in the future.

Maintenance of Hard Floor Coverings

The maintenance of hard floors has many aspects, but this paper will be restricted to telling how floors can best be cleaned, scrubbed, and waxed in order to maintain for them an attractive appearance.

The Mexican method of making hard lime floors

The variety and complexity in cloud marketplaces is growing, making it difficult for cloud consumers to choose cloud services from multiple providers in an economic and suitable way by taking into account multiple objectives and constraints. In this paper, we present an extension of CloudSim implementing cloud management functionality to enable the assessment of consumer-oriented brokering schemes. The underlying discrete-event simulation framework allows evaluating their performance in more realistic operating conditions in a repeatable manner. We integrate brokering mechanisms to support a multi-criteria location-aware selection of virtual machines in multi-cloud environments by implementing a greedy heuristic and two large neighborhood search metaheuristics. Based on microbenchmarks of real cloud offerings and a diverse set of scenarios and workloads, we conduct simulation experiments to assess the performance of our approaches. The results show that approximately 10 – 12% of the total costs can be saved by using a large neighborhood search approach compared to the greedy heuristic. Finally, we analyze and discuss the trade-off between costs and latency as well as the impact of region constraints, showing, e.g., that latency improvements often come at a high price and a greater regional flexibility can lead to latency improvements while solely optimizing costs. Using real data of cloud marketplaces, we show that the proposed CloudSim extension can support decision makers as a tool for assessing cloud portfolios and market dynamics.