Penelitian ini bertujuan untuk menyelidiki pengaruh metode belajar Students Team Achievement Division (STAD) dan Self Directed Learning (SDL) terhadap peningkatan kemampuan keterampilan roll depan ...yang dilaksanakan dalam situasi pembelajaran normal dengan jumlah 12 kali pertemuan. Metode penelitian menggunakan quasi eksperimen dengan jumlah sampel 37 orang yang terdiri atas 19 orang sampel siswa dengan perlakuan gaya mengajar STAD dan 18 orang siswa mendapatkan perlakuan SDL. Data penelitian didapatkan dengan cara uji roll depan di awal dan akhir penelitian. Analisa deskriptif dan inferensial kemudian dilakukan untuk mendapatkan hasil uji rerata beda dari para sampel. Kesimpulan dari penelitian ini adalah terdapat perbedaan yang signifikan pada hasil akhir dan awal test keterampilan handstand melalui metode STAD dan SDL pada materi pembelajaran senam roll depan, dengan keunggulan pada gaya mengajar STAD yang lebih signifikan dibandingkan gaya mengajar SDL.
Roll-coating, also known as roll-to-roll coating or web coating is a continuous and high-speed method used in various industrial applications to apply a thin and uniform layer of material onto a ...substrate. This process is commonly employed in industries such as electronics, photovoltaic, printing, packaging, and other fields where precise and consistent coating is essential. Here we present an asymptotic analysis of forward roll coating over a rigid substrate for low Weissenberg number viscoelastic fluids. The analysis uses lubrication theory coupled with regular perturbation theory assuming a simplified Phan-Thien-Tanner (SPPT) constitutive equation and small values of the extensibility parameter ε. The analytical expressions of velocity fields, pressure gradient and pressure fields are obtained while the load carrying force, and power input are estimated by numerical solutions (4th order Runge-Kutta). Increases in both Wi and ε increases the pressure gradient in the nip region and increases in viscoelasticity reduce the overall force on the roll. Further, SPTT model predicts 14% lower pressure for
W
i
(
=
0.8
)
in the nip region when compared to Newtonian model.
The steady‐state laminar nonisothermal, incompressible viscoelastic fluid flows with the Jeffrey model between two counterrotating (same direction) rolls are studied analytically. The Jeffrey model ...is reduced to the Newtonian model after some appropriate modifications. The new dimensionless governing equations are acquired through suitable nondimensional values. The lubrication approximation theory is employed for the simplification of emerging equations. The exact expressions for pressure gradient, velocity, temperature, and flow rate are accomplished whereas some quantities of interest such as pressure, coating thickness, power transmitted by rolls to the fluid, and roll separation force are computed numerically by using a numerical method. The influence of emerging parameters such as the ratio of relaxation time to the retardation time λ
1 ${\lambda }_{1}$, magnetohydrodynamic (MHD) parameter M $M$ and Brinkman number B
r $Br$ on velocity profile, temperature profile, pressure gradient, pressure distribution, coating thickness, power input, and force of roll separation are presented numerically in a tabular way and specific outcomes are demonstrated graphically. The MHD acts as a regulatory parameter for various quantities of important interest, such as velocity, coating thickness, and temperature. It is worth noting that the coating thickness decreases as modified capillaries number is increased.
In this article, the rheological effects of an Oldroyd 8-constant fluid model in the presence and absence of magnetic force (MHD) are investigated while traveling between the two rolls rotates in the ...same direction. The governing equations of the fluid flow have been simplified using the lubrication approximation theory (LAT). Analytical solutions in the presence and absence of MHD are presented using (i) Adomian’s decomposition method (ADM), (ii) Homotopy analysis method (HAM), and numerical simulations are performed by (iii) the finite difference method. We present the results of our findings through various graphs and validate the numerical and analytical methods through detailed tables of error comparisons. It has been found that non-Newtonian and magnetic parameters have a significant impact on the velocity profiles, pressure gradient, pressure distribution, separation points, and coating thickness. The material parameters α1 (dilatant parameter) and α2 (pseudoplastic parameter) notably affect the velocity profile of the fluid flow between two rolls. Increasing α1 causes shear thickening and decreases the velocity profile, while increasing α2 results in shear thinning and increases the velocity profile due to diminished internal resistance. A relationship exists between the MHD parameter m and the flow velocity. The greater the MHD force, the higher the resistance in fluid flow, resulting in lower velocity. A reasonable agreement has been found between Newtonian fluid and Oldroyd 8-constant fluid, assuming all the non-Newtonian parameters to be zero. The results provided a comprehensive methodology for regulating the coating thickness by adjusting the modified Capillary’s number in the industry.
The aims this research to determine whether there is influence of upper extremity strength, lower extremity strength and motivation on forward roll of achievement learning. The type of this study is ...a correlational survey involving independent variables consisting of upper extremity strength, lower extremity strength and motivation while the dependent variable is forward roll of achievement learning. The research sample was 40 students from SMK Layoa Bantaeng who were taken by purposive random sampling. The research instrument was arm muscle strength test using push and pull dynamometer, leg muscle strength test using leg dynamometer, and motivational questionnaire as well as forward roll process instruments. The results showed that there was a significant effect of upper extremity strength on forward roll of achievement learning (p <0.05), there was a significant effect of lower extremity strength on forward roll of achievement learning <0.05), there was a significant effect of motivation on forward roll of achievement learning (p <0.05) and there is a significant effect together of upper extremity strength, lower extremity strength and motivation on forward roll of achievement learning (p <0.05).
► A mechanism for misting with dilute polymer solutions in forward roll coating is visualized with a high-speed camera. ► Misting has been related to elasticity of the solutions through their ...relaxation times. ► Misting was quantified by measuring drop size, count and mass concentration. ► As relaxation times rise: larger and fewer drops are produced; mass concentration of mist falls to a minimum and then rises. ► Slight elasticity suppresses misting whereas more of it aggravates.
Misting of liquids in forward roll coating is a problem under certain conditions. The relaxation time is known to influence misting but the fundamental mechanisms are not clear. A new mechanism for misting of dilute non-Newtonian liquids was proposed based on visualizations with a high-speed camera. With these liquids, filaments were created which sometimes transformed into beads-on-string structures and the beads were ejected as mist droplets when the structures broke. Misting was quantified by measuring sizes of the generated droplets, their count and mass concentration. The measurements were related to elasticity of the solutions through their relaxation times. Small levels of elasticity reduce the amount of misting, but higher levels lead to an increase.
Roll coating is a comparatively simple and common technology for coating of continuous substrates like paper, coils, or foils, where the fluid is metered through the gap between two rolls. Rolls ...wrapped with a deformable rubber layer enable a precise metering for low fluid amounts and lead additionally to higher process stability. Many efforts have been made to investigate the influencing factors of deformable roll coating by experimental and numerical methods. Beside configurations with positive gaps, which are comparable to rigid roll setups, negative gaps, where only the elasticity of the rubber layer prevents overlapping of the rolls, are of interest as such configurations enable thin liquid layers. The main influencing factors on the volume flow rate through the gap are viscosity, average velocity, effective radius, Young’s modulus, load or pre-set gap height, and partly rubber thickness, when an influence of the layer height is assumed. The dependency is often given in empirically or numerically based power law relationships. In contrast to this, in the present study, an analytically based solution is used to investigate the influencing factors in deformable roll coating with negative gaps. This continues the authors' previous work, in which the analytical solution was derived. As a result, a general agreement with numerical and experimental results from literature is found. Additionally, the analytical approach allows for the first time the ability to quantify further trends. The proposed power law exponent for the dimensionless load and elasticity numbers from literature cannot be considered as constant in the whole common application range of roll coating but remarkable trends appear. Additionally, a new criterion for the critical rubber cover thickness is developed analytically which describes the limit value of the negligible influence of the rubber cover thickness on the volume flow rate. The present investigation enables the explanation of different literature results and offers a more general view in the understanding of roll coating processes.
The flow of Newtonian fluids through the deformable nip of a high speed roll coater was experimentally studied. A digital video system was used for the observation of the formation, elongation and ...break-up of fluid filaments at the exit of the nip and to investigate how misting droplets are ejected to the surroundings. The pressure profile in the nip was obtained by a miniaturized piezoelectric transducer mounted on one of the coater rolls. Experimental results show that both film splitting and air entrainment into the nip can be responsible for misting occurrence when a low load is applied between the rolls. When a high load is applied, misting can be eliminated and a periodic flow is generated in the nip gap.
The objective of this study is to compare the general body measurements and shoulder shapes of Korean and American elderly women to supply basic data for the apparel design. The anthropometrics data ...was collected including both direct and indirect measurements of 283 women over the age of 55 in Korean and the American women. The statistical methods used for the analysis of measurement data are the T-test, Exploratory data analysis, ANOVA and Duncan-test respectively. The results of the T-test indicated that there is a significant difference in the 14 body measurement items except of waist circumference. The results of exploratory data analysis, an independent relationship between shoulder slope angle and forward shoulder roll of Korean women. On the other hand, there is a dependent relationship that the bigger shoulder slope and forward shoulder roll with wide cross back shoulder of American women. Comparison of mean among the three different age groups, aged 55?59 group shows significant differences in the value of difference between cross hack shoulders and horizontal shoulder width. This finding indicates that the wide and forward roll shoulder needs to special pattern making like ease amount and curvature for fit and comfort for women`s apparel.
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