Rolling Ability Research Articles

Dynamic lateral adhesion force of water droplets on microstructured hydrophobic surfaces

This study investigates the change of the dynamic lateral adhesion forces of water droplets on microstructured surfaces by varying their hydrophobicities. While hydrophobic surfaces showed significant asymmetry in advancing-to-receding profiles, superhydrophobic surfaces did not. As a result, hydrophobic surfaces required greater moving forces at the moment of change of the moving direction than superhydrophobic surfaces. In addition, lateral adhesion forces measured from hydrophobic surfaces were much higher than those from superhydrophobic surfaces. In the present experimental conditions, water droplets did not roll on the surfaces with lateral adhesion forces larger than 21mgf. These results support the possibility that the rolling ability of a water droplet on a surface can be evaluated by measuring the lateral adhesion force.

Environmental influence on preterm and term infants over rolling movement.

Introduction: Lifelong constant changes occur in the complexity and quality of the execution of motor actions, characterizing the motor development. External (environmental) factors may act positively or negatively in the course of some motor slill, such as the ability of rolling. Objective: It is about an analytical cross-sectional study aimed to analyze the positioning of the cradle of preterm and terms infants relating to the rolling movement. Method: It is about an analytical cross-sectional study. The sample comprised 27 infants of both genders, divided into two groups (G1 and G2). G1 was composed of 8 premature infants included in a motor stimulation project and G2 was composed of 19 term infants enrolled in a nursery school. A questionnaire was sent to parents / caretakers and later a practical assessment was held in which the rolling motion was stimulated with rattles, three times for each side (left / right), observing the presence or absence of facilitation in this action. Results: It was found that in both groups, most of the cradles were placed with one of the sides against the wall and the statistical analysis of the data indicated a significant correlation to the placement of the cradle in space and the ease of rolling for preterm infants (p<0.05) and terms infants (p<0.01), while the stimulation was performed by the study researcher. Conclusion: Therefore, it was possible to conclude that there was an ease of rolling to the contralateral side of the wall, i.e. to the side of largest environmental stimulus, which emphasizes the importance of a sensory-rich environment in the course of a proper infant development.

The influence of heat treatment and deep rolling on the mechanical properties and integrity of AISI 1060 steel

This work addresses the influence of distinct microstructures and deep rolling parameters on the behaviour of AISI 1060 steel. For this purpose, the work material was initially subjected to subcritical and full annealing as well as to hardening through quenching and tempering. The specimens were subsequently deep rolled under different rolling pressures and numbers of passes. The findings indicate that plastic deformation increases with rolling pressure and number of passes due to more intense cold working and that under identical deep rolling conditions the fully annealed material presents more severe deformation than the subcritically annealed samples. Moreover, the ability of deep rolling to increase surface hardness decreases with the elevation of the hardness of the original material. The values of the yield and ultimate tensile strength were affected in different manners by deep rolling depending on work material condition and the tensile residual stresses observed after turning were converted into compressive values by deep rolling. Finally, the elevation of rolling pressure and number of passes presented distinct effects on the microhardness distribution beneath the surface depending on the work material condition.

Effect of particle morphology and size on roll compaction of Ti-based powders

Titanium and blended titanium alloy powders with varying particle morphologies and particle sizes were investigated for their rolling behaviours. The rolling behaviour was evaluated by measuring the density and thickness of strips produced by varying the roll gap size. The study was carried out to determine if the CSIR-Ti powder produced using the newly developed CSIR process could be successfully used in direct powder rolling and compare its rolling ability to that of potentially competing powders that are already commercially available. Three commercially available powders of different morphologies were investigated together with the new CSIR-Ti powder. Powder compressibility, flowability, particle morphology and particle size were determined. Direct powder rolling was carried out using a 55mm roll diameter rolling mill by varying the roll gap size. Densities and thicknesses of the rolled strips were measured for every roll gap size used. Results indicate that the rolling behaviour varies with changes in morphology. Spongy and angular shaped powders were successfully rolled to dense strips with no visible defects. Spongy powders achieved higher densities than angular powders. The strip thicknesses decreased as the densities increased for all powders. Spherical powders produced strips that disintegrated as they emerged at the exit zone. Alloying Ti with Al–V master alloy powder significantly altered the rolling behaviour of the Ti powders.

Dynamic rolling analysis of triangular-bipyramid robot

SUMMARYIn this paper a rolling robot resembling the shape of a triangular-bipyramid is proposed. The robot has three degrees of freedom and is formed by connecting two tripod mechanisms with three spherical joints. By kinematic analysis, the robot can be viewed as a planar four-bar linkage. Further, its dynamic rolling ability is discussed by Zero Moment Point (ZMP) analysis. We show that the robot has the capability to roll, adjust its step length, and switch rolling directions. These functions are verified by a series of simulations with a CAD (computer-aided design) model and experiments with a prototype.

Homing of Neural Stem Cells From the Venous Compartment Into a Brain Infarct Does Not Involve Conventional Interactions With Vascular Endothelium

Human neural stem cells (hNSCs) hold great potential for treatment of a wide variety of neurodegenerative and neurotraumatic conditions. Heretofore, administration has been through intracranial injection or implantation of cells. Because neural stem cells are capable of migrating to the injured brain from the intravascular space, it seemed feasible to administer them intravenously if their ability to circumvent the blood-brain barrier was enhanced. In the present studies, we found that interactions of hNSCs in vitro on the luminal surface of human umbilical vein endothelial cells was enhanced following enforced expression of cutaneous lymphocyte antigen on cell surface moieties by incubation of hNSCs with fucosyltransferase VI and GDP-fucose (fhNSCs). Interestingly, ex vivo fucosylation of hNSCs not only did not improve the cells homing into the brain injured by stroke following intravenous administration but also increased mortality of rats compared with the nonfucosylated hNSC group. Efforts to explain these unexpected findings using a three-dimensional flow chamber device revealed that transmigration of fhNSCs (under conditions of physiological shear stress) mediated by stromal cell-derived factor 1α was significantly decreased compared with controls. Further analysis revealed that hNSCs poorly withstand physiological shear stress, and their ability is further decreased following fucosylation. In addition, fhNSCs demonstrated a higher frequency of cellular aggregate formation as well as a tendency for removal of fucose from the cell surface. In summary, our findings suggest that the behavior of hNSCs in circulation is different from that observed with other cell types and that, at least for stroke, intravenous administration is a suboptimal route, even when the in vitro rolling ability of hNSCs is optimized by enforced fucosylation.

Infant rolling abilities – the same or different 20 years after the back to sleep campaign?

AimTo compare the order and age of emergence of rolling prone to supine and supine to prone before the introduction of back to sleep guidelines and 20years after their introduction. MethodsThe original normative data for the Alberta Infant Motor Scale (AIMS) were collected just prior to the introduction of back to sleep guidelines in 1992. Currently these norms are being re-evaluated. Data of rolling patterns of infants 36weeks of age or younger from the original sample (n=1114) and the contemporary sample (n=351) were evaluated to compare the sequence of appearance of prone to supine and supine to prone rolls (proportion of infants passing each roll) and the ages of emergence (estimated age when 50% of infants passed each roll). ResultsThe sequence of emergence and estimated age of appearance of both rolling directions were similar between the two time periods. ConclusionThe introduction of the supine sleep position to reduce the prevalence of Sudden Infant Death Syndrome (SIDS) has not altered the timing or sequence of infant rolling abilities. This information is valuable to health care providers involved in the surveillance of infants’ development. Original normative age estimates for these two motor abilities are still appropriate.

Populational-genetic analysis of phenotype frequency of two qualitative properties of the tongue of the population of Zivinice

The objectives of this research were to establish the recessive phenotype frequency of the(in)ability of tongue rolling (fr) and frequency of the(in)ability of tongue folding. The data were collected by means of direct analysis and interviews with pupils from 5th to 8th grade. The research was conducted in rural and urban areas of Zivinice Municipality (OS Zivinice and OS Basigovci). The sample comprised 438 persons of both sexes (202 boys and 236 girls) 11-16 years of age. 197 respondents were from urban and 241 from rural area. The analysis of the obtained results showed that the phenotype frequency of the (in)ability of tongue rolling in Zivinice Municipality is 20,30% with relative frequency of recessive allele qr=0,45, while in the Basigovci area the phenotype frequency of the(in)ability of tongue rolling is 41,90%, with relative frequency of recessive allele qr=0,64. The phenotype frequency of the(in)ability of tongue folding in Zivinice is 32,48%, relative frequency of recessive allele qu=0,56, while the incidence of same phenotipe in Basigovci is 44,81%, and relative frequency of recessive allele is qu=0,66. The analysis of the results in Živinice Municipality show that the frequency of recessive allele is not different from the one found in the previous researeches in the regions of B&H and has approximate value of the frequency of reccesive allele from Gradačac qr=0,55.

Abrasive rolling effects on material removal and surface finish in chemical mechanical polishing analyzed by molecular dynamics simulation

In an abrasive chemical mechanical polishing (CMP) process, materials were considered to be removed by abrasive sliding and rolling. Abrasive sliding has been investigated by many molecular dynamics (MD) studies; while abrasive rolling was usually considered to be negligible and therefore was rarely investigated. In this paper, an MD simulation was used to study the effects of abrasive rolling on material removal and surface finish in the CMP process. As the silica particle rolled across the silicon substrate, some atoms of the substrate were dragged out from their original positions and adhered to the silica particle, leaving some atomic vacancies on the substrate surface. Meanwhile, a high quality surface could be obtained. During the abrasive rolling process, the influencing factors of material removal, e.g., external down force and driving force, were also discussed. Finally, MD simulations were carried out to examine the effects of abrasive sliding on material removal under the same external down force as abrasive rolling. The results showed that the ability of abrasive rolling to remove material on the atomic scale was not notably inferior to that of abrasive sliding. Therefore, it can be proposed that both abrasive sliding and rolling play important roles in material removal in the abrasive CMP of the silicon substrate.

Genetics of Morpho-Physiological Traits in Segregating Populations of Interspecific Hybrid Rice Under Stress and Non-Stress Conditions

Drought is one of the major constraints for rice (Oryza sativa L.) production in the rainfed ecologies in Sub-Saharan Africa. The objectives of this study were to investigate the genetic effects of morpho-physiological traits controlling drought-stress tolerance. Five Oryza glaberrima genotypes, four interspecific inbred lines, two interspecific hybrids, and two O. sativa lines and their progenies from a North Carolina II mating design were evaluated at ICRISAT in Mali under drought and fully irrigated conditions in 8 × 8 lattice designs. Data were collected on morpho-physiological traits, such as plant height, leaf rolling and stress recovery ability. General combining ability (GCA) effects for females and males were significant for all traits. Female GCA and specific combining ability (SCA) effects were significant for tiller number, plant height, and specific leaf dry weight. Heritability estimates based on variance ratios ranged from 47% to 67% for plant height, leaf area, specific leaf dry weight, and SPAD (chlorophyll); these were not significant for tiller number, which was controlled by overdominance. Heritability estimates based on regression were significant and ranged from 22% to 72% for drought-tolerance scores and leaf rolling scores. Highly significant positive relationships were observed between F3 and F4 generations for drought tolerance and leaf-rolling scores in all the populations examined. Both additive and non-additive genetic affects were important in controlling morpho-physiological traits; hence breeding procedures that exploit both GCA and SCA should be considered to improve drought tolerance in this rice germplasm.

Photosynthesis performance of non-rolling and flag leaf rolling wheat genotypes during temperature stress

The objective of this study is to determine the potential of photosynthesis for the detection of heat stress in three wheat genotypes ‘Grekum 476’, ‘Otan’ and ‘Alba’, which are known to differ in their leaf rolling ability. The results of measurements of gas-exchange, stomatal conductance and pigment determination indicate that the use of a temperature of 40 °C allows to distinguish the non-rolling and leaf rolling wheat genotypes in their photosynthetic responses to heat stress.High temperature acclimation by the leaf rolling wheat genotypes caused marked changes in the pigment composition and function of the photosynthetic apparatus. Thus, stomatal regulation (changes in gH 2 O values), the changes in WUE and modification of the photosynthetic pigment apparatus as well as the up-rolling of the flag leaf at a higher irradiance are essential factors that contribute to avoid heat and drought conditions as well as photoinhibition of the photosynthetic apparatus in major parts of the leaf. The two most leaf ...

Texture evolution and magnetostriction in rolled (Fe 81Ga 19) 99Nb 1 alloy

The addition of Nb could improve rolling ability of Fe 81Ga 19 alloy during rolling process. The (Fe 81Ga 19) 99Nb 1 sheet with thickness of 0.6 mm was prepared by conventional hot rolling, warm rolling and cold rolling and its magnetostriction effects were studied. It demonstrates that the magnetostriction of the sheet is closely related to rolled texture, and the recrystallization texture depends on heat treatment process. The {1 1 1} 〈 u v w 〉 and near {0 0 1}〈1 1 0〉 rolling-textures are major in the rolled sheet, and the magnetostriction λ ∥ only is about 26 ppm. A near {0 1 1}〈1 0 0〉 texture and a {0 0 1}〈1 0 0〉 texture were formed in the recrystallized sheets which were quenched into water after 2 h annealing at 1250 °C and 1300 °C, and their magnetostriction (3/2) λ RD are around 106 ppm and 134 ppm, respectively.

Prediction of Discharge Destination After Stroke Using the Motor Assessment Scale on Admission: A Prospective, Multisite Study

Brauer SG, Bew PG, Kuys SS, Lynch MR, Morrison G. Prediction of discharge destination after stroke using the Motor Assessment Scale on admission: a prospective, multisite study. Objective To determine if admission functional status, measured with the Motor Assessment Scale (MAS), was predictive of discharge destination to home or residential aged care in patients with stroke undergoing rehabilitation. Design Cohort study. Setting Inpatient rehabilitation units. Participants Adults (N=566) diagnosed with stroke undergoing inpatient physiotherapy at one of 15 units in Australia. Intervention Multidisciplinary rehabilitation. Main Outcome Measure Discharge home versus residential aged care. Results Prestroke residential status, gait ability measured with the MAS (MAS-5), rolling ability (MAS-1), and age were able to correctly predict 99% of patients with stroke discharged home and 33.3% discharged to residential aged care facilities, producing an accuracy of 87.3%. Odds ratios indicate that for every 1-point increase in MAS-5 (gait), subjects were 1.66 times more likely to go home (95% confidence interval [CI], 1.28–2.27; P<.001). Similarly, for every 1-point increase in MAS-1 (rolling), subjects were 1.28 times more likely to go home (95% CI, 1.11–1.49; P<.01). Conclusions Two items of the MAS assessed on admission to rehabilitation—gait and rolling—in conjunction with basic demographic information of age and prestroke residential status, were highly predictive of discharge from rehabilitation to home.

Flexural Fracture Strength, Fracture Locations, and Monte Carlo Predictions for a Silicon Nitride by Ten U.S. Laboratories

The work reported was conducted to provide a basis for a number of structural ceramic mechanical property standardization activities in the United States, Germany, Japan, and Sweden. A comparison of key property values of a commercial silicon nitride determined in a number of laboratories was a major objective. The work reported was conducted by 10 U.S. laboratories on GN‐10 silicon nitride, and represented the U.S. work within an International Energy Agency program including the United States, Germany, Japan, and Sweden. Fracture location analyses showed that fracture location within the inner span often was not a linear function of location within the span. Some of this behavior was explained by random sampling effects based upon simulation predictions, but some was apparently dependent upon friction within the fixtures in spite of efforts to minimize it. Flexural strengths were measured at 25° and 1250°C in air and were analyzed using the two‐parameter Weibull model in terms of m and σΘ using both linear regression (LR) and maximum likelihood (ML) methods. Under the measurement conditions for the 10 room‐temperature strength sets, the value of the ML estimator for m varied by as much as 36%, while the value for the σΘ parameter estimator varied only 3.3%. The LR estimator for m varied by about 54%. For the high‐temperature specimens, the ML estimator for m varied by 48% while the LR estimator varied by 38%. Ranked fracture location analysis showed that the high‐temperature fracture locations were more random than those in the room‐temperature specimens, and was probably due to friction in the high‐temperature fixtures. There was little pin rolling ability in many of the high‐temperature fixtures used. Monte Carlo and one‐way analysis‐of‐variance (ANOVA) methods provided insight into the consistency of the strength values. Monte Carlo predictions showed that for room‐temperature strength, the maximum likelihood estimator m for all 10 laboratories fit within the 10% and 90% confidence bounds for 30 specimen sets. The dispersion of the high‐temperature data was such that the m estimator satisfied the model only at the 1% and 99% confidence levels for the 15 specimen sets. ANOVA results showed that for the room‐temperature flexural strength, data from all 10 laboratories were not distinguishable for this evaluator at the 95% confidence level and that scatter within individual data sets was a larger effect than was the variation between the data sets. For the high‐temperature data, the results from one laboratory were clearly outside the allowable range at this confidence level.

The Effects of Protein Content of Flour and Emulsifiers on Tanoor Bread Quality

Abstract Emulsifiers (SSL, GMS-90, DATEM, S-570, S-1170, S-1670, P-1670) with three concentrations (0·25%, 0·50%, 0·75%) and three flour types (soft red winter wheat flour with 9·7% protein, hard red winter wheat flour with 11·2% protein, and hard red spring wheat flour with 14·2% protein) were used to evaluate their effects on tanoor bread quality. For baking breads, an air impingement oven was used. The low and high protein flours were not suitable for this bread because breads made from high protein flour had significantly lower scores for crust smoothness, uniformity of thickness and crumb appearance, but higher scores for area index, first-day rolling, first- and second-day tearing. The low protein flours produced breads with light crust colour and significantly lower scores for rolling, and first- and second-day tearing quality characteristics. Rolling and tearing qualities were improved when high concentrations of emulsifiers were used with low protein flour. The results of this study indicate that optimum tanoor bread was produced from moderate protein flour (11·2%). Emulsifiers improved first- and second-day tearing, and first-day rolling ability, but reduced the score for crust smoothness. Sucrose esters P-1670, S-1670 and S-1170 gave breads with higher overall scores compared to the other emulsifiers studied, but with darker crust colours. Shelf life stability indicated that P-1670, S-1670 and S-1170 at 0·50% concentration improved tearing but not rolling ability characteristics after five days storage at room temperature.

Tongue Rolling in the Classroom

Tongue rolling, the ability to shape the tongue into a longitudinal trough, is a trait that is commonly used in the classroom as an example of human inheritance. This polymorphic trait is easily determined and its mode of inheritance is presumed to be simple. According to Sturtevant (1940), who first described the inheritance of tongue rolling, the ability to do so is due to a pair of alleles. The ability to roll one's tongue is dominant to the inability to do so. According to this hypothesis, children of tongue rollers can be found to be unable to roll their tongue, but children of nonrollers should always be non-rollers. This was found to be untrue in our classes. From the pedigrees of hundreds of students, we found a few tongueroller students whose parents were unable to roll their tongue and students whose parents were tongue rollers but whose own parents were non-rollers. Intrigued by these results we surveyed the literature that revealed that the ability of tongue rolling is far from being a simple Mendelian trait. Though Hsu (1948) and Garhes (1952) confirmed Sturtevant's original hypothesis, a few researchers had doubts. Matlock (1952) studying 33 pairs of identical twins observed seven pairs who were discordant. From these observations he had to conclude that tongue rolling is not entirely hereditary. Reedy, Szczes, and Downs (1971) compared 193 pairs of identical and fraternal twins. They concluded that the data were inconsistent with the hypothesis of chance fluctuations and that the ability to roll one's tongue was strongly influenced by hereditary factors. However, Martin (1975) from a comparable study that included 47 identical and fraternal twins did not find any statistical evidence for greater concordance in identical twins. He concluded that there was no evidence for a genetic basis for tongue rolling. We decided to pool the data of Matlock, Reedy, Szczes, and Downs and Martin (table 1). The Chi Square of the pooled data is 1.89. Because the probability is greater than 5 percent, we have to conclude that there is no evidence for a greater concordance in identical twins. This can be further confirmed by another statistical test, which estimates the differences between the proportions of concordance in the fraternal and identical twins by calculating the con-

Relation of Kinesthetic Perception to a Selected Motor Skill for Elementary School Children

Abstract The purposes of this study were (a) to determine whether or not selected measures of kinesthesis, involving arm positioning, were related to measures of accuracy in ball rolling, and (b) to discover whether or not there were any differences between elementary school boys and girls in kinesthetic measures and in ball rolling ability measures. Forty-seven first and second grade boys and girls were tested on four arm positioning measures and two ball rolling measures. The results of the study indicated that: (a) there is no significant relationship between ball rolling and positional measures of kinesthesis; (b) there are no real differences between boys and girls in their ability to accurately repeat positional measures of kinesthesis; and (c) boys are significantly superior to girls in their ability to manipulate accurately large and small balls, as measured by the tests used in this study.