The Development of Electronic Practicum Modules at Electronic Course for Physics Education Program

This study aimed to design a practicum module in electronics courses. The researcher initially carried out the developed module to analyze the level of validity and students’ responses to the electronic practicum module that the researcher had created. The module developed was validated by two experts. The subjects of this research were students of the Physics Education Program at the Muhammadiyah University of Makassar in the odd semester in the academic year of 2019/2020. This research employed a Research and Development (R&D) design. The development was carried out using the 4D model with four stages: Define, Design, Develop and Disseminate proposed by Thiagarajan. The results showed that the expert assessment of the electronic practicum module that had been developed using the Gregory test closeness model obtained a strong relevance level because it had an internal consistency coefficient of 100% and was declared to meet the eligibility criteria (valid). The percentages of students’ responses in the three indicators (interested in using the module, easy to understand the module content and easy-to-understand module language) were 83%, 81 %, and 81%, respectively. Based on the description above, it can be concluded that the electronic practicum module developed is declared valid, and students respond well to the use of the electronics practicum module.

The role of perceived organizational support in work-leisure conflict

In this study, it is aimed to examine the effect of perceived organizational support of employees on the level of work-leisure conflict. The working group of the research consists of the personnel of the Ministry of Youth and Sports, who are working in Ankara. In addition to the personal information form, the “Work-Leisure Conflict Scale” and “Perceived Organizational Support Scale” were used in the data collection phase of the research. T-test for comparing the total scores obtained from the scales with the variables of regular activity participation, daily leisure time sufficient; Descriptive statistics were used to determine the scores obtained from the scales, Pearson Moment Correlation Test and Regression Analysis research were used to determine the relationship between the variables. For this study, the internal consistency coefficient for WLC was determined as .95, and the internal consistency coefficient for POS was determined as .90. The findings show that the participants showed an average WLC level, on the other hand, they had POS scores above the average. On the other hand, it was found that there were significant differences between the participants' daily leisure time, regular activity participation variables, and WLC and POS levels, there was a negative and low-level relationship between WLC and POS (r1=-.231, p<.01). It has been determined that POS affects WLC. The findings reveal important data to draw attention to the perceived organizational support of employees in reducing work-leisure conflict. ​Extended English summary is in the end of Full Text PDF (TURKISH) file. Özet Çalışmada işgörenlerin algılanan örgütsel desteğin iş-serbest zaman çatışma düzeyine etkisinin incelenmesi amaçlanmıştır. Araştırmanın çalışma grubunu, Ankara ilinde görevlerini sürdürmekte olan Gençlik ve Spor Bakanlığı personeli oluşturmaktadır. Araştırmada veri toplama aşamasında kişisel bilgi formunun yanı sıra “İş-Serbest Zaman Çatışma Ölçeği” ile “Algılanan Örgütsel Destek Ölçeği” kullanılmıştır. Ölçeklerden elde edilen toplam puanların düzenli etkinlik katılımı, günlük serbest zaman süresinin yeterli görülme değişkenleri ile karşılaştırılmasında T-testi; ölçeklerden elde edilen puanların belirlenmesinde betimsel istatistikler, değişkenler arasındaki ilişkinin belirlenebilmesi için Pearson Momentler Çarpımı Korelasyonu Testi ve Regresyon Analizi araştırma kullanılmıştır. Bu çalışma için İSZÇ için iç tutarlılık katsayısı .95, AÖD için iç tutarlılık katsayısı .90 olarak belirlenmiştir. Elde edilen bulgular katılımcıların ortalama İSZÇ düzeyi gösterdikleri, buna karşılık ortalamanın üzerinde AÖD puanları ortaya koyduklarını göstermektedir. Diğer yandan katılımcıların günlük serbest zaman süresi, düzenli etkinlik katılımı değişkenleriyle İSZÇ ve AÖD düzeyleri arasında anlamlı farklılıklar olduğu, İSZÇ ve AÖD arasında negatif yönlü ve düşük düzeyde bir ilişkinin olduğu ve (r1=-.231, p<.01). AÖD’nin İSZÇ’yi etkilediği belirlenmiştir. Bulgular işgörenlerin iş serbest zaman çatışmasını azaltmada algılanan örgütsel desteğe dikkat çekmek üzere önemli veriler ortaya koymaktadır.

Physicochemical Properties and Digestion Resistance of Acetylated Starch Obtained from Annealed Starch

One of the examples of physical starch modifications is the retention of a starch suspension in water having a temperature slightly lower than the pasting temperature (annealing). The aim of this study was to investigate the effect of the annealing process performed at various temperatures as the first stage of starch modification. The annealed starch preparations were then esterified using acetic acid anhydride. Finally, the annealed and acetylated starch preparations were determined for their properties. The annealing of starch before acetylation triggered changes in the properties of the modified preparations. It contributed to a higher degree of starch substitution with acetic acid residues and to the increased swelling power of starch. Both these properties were also affected by the annealing temperature. The highest resistance to amylolysis was found in the case of the starch preparation annealed at 53.5 °C and acetylated. The double modification involving annealing and acetylation processes increased the onset and end pasting temperatures compared to the acetylation alone. Similar observations were made for the consistency coefficient and yield point.

Study of Some Hydraulic Parameters of A solar-Powered Drip Irrigation System

An experiment was carried out in Al-Rifai District - Dhi Qar Governorate, to study the effect of the distance between drippers and their discharge on friction losses, coefficient of variation, and emission consistency of the drip irrigation system. Spiral drippers with a design discharge of 4 and 8 L.hr"1. While the emitters were installed at distances of 20, 40, 60 (cm). The actual discharge of the droplets was measured and the friction losses, emission consistency coefficient, and discharge variance ratio were calculated. The results showed that the distance between the emitters 60 cm gave the lowest percentage of friction losses, which amounted to 0.165, 0.204 (m) for drippers with design drainage of 4, 8 L.hr-1. The best values of the emission consistency coefficient and the variance ratio in the emitters discharge were 95.44 and 28.41% when using the 8L.hr-1 and the distance between the emitters is 60 cm, respectively.

Comprehensive Effect of the Time and Water-Cement Ratio on the Rheological Properties of Power-Law Cement Grouts

The rheological properties of cement grouts are significantly affected by the changes of the time and the water-cement ratio, which determine the diffusion state of grouts in rocks and soils and influence the outcome of projects. In this study, Portland cement grouts with water-cement ratios of 0.50, 0.55, 0.60, 0.65, 0.70, and 0.75 at six moments, including 0 minutes, 5 minutes, 10 minutes, 20 minutes, 30 minutes, and 60 minutes, were evaluated to figure out the comprehensive effect of the time and the water-cement ratio on the rheological properties of power-law cement grouts. The results showed that the water-cement ratio had a great influence on both the consistency coefficient and the rheological index of the power-law cement grouts. The former appeared to have a downward trend with the increase of the water-cement ratio, and the latter appeared to have an upward trend. There was a rising tendency between the time and the consistency coefficient, while the rheological index was less affected by time. The difference between its maximum and minimum values was within 5%. Combined with the perspectives of statistical theory, practical applicability, and accuracy, the exponential model was the optimal model for showing the relationship between the comprehensive effects of the time, water-cement ratio, and consistency coefficient of the power-law cement grouts. The linear model was the optimal model of the rheological index based on the comprehensive effect of time and the water-cement ratio. Based on this, a power-law rheological equation with consideration of the comprehensive effect of time and water-cement ratio was established. The research results could not only improve the rheological theory of power-law cement grouts but also provide technical support for engineering practice.

Rheological and Nutritional Characterization of Sweet Corn By-Product (Cob) to Develop a Functional Ingredient Applied in Dressings

In this study, a flour from corn cob (central core of the maize ear, stage R4) was obtained through three treatments. The three flours obtained were characterized by bromatological analysis, yield, and granulometry. Additional dressing-type oil in water (O/W) emulsions were developed, varying the formulation by incorporating distinct amounts of corn cob flour. The formulations' stability was evaluated over a period of 21 days, determining the particle size, creaming index, coalescence rate, consistency coefficient (k), and flow behavior indices (n). Results have shown significant differences in protein, fat, and carbohydrate content in the flour, depending on the cooking treatment. A good percentage of grinding yield was obtained (98%), in addition to several fractions by granulometry (60, 120, 250 MESH), showing differences in their nutritional content. Finally, the particle size of O/W emulsions developed varied among formulations. The combination of 0.6% of xanthan gum (XG) and corn cob flour showed major stability in average droplet size. No significant differences were observed in the coalescence rate values for the three formulations. Still, significant differences in the creaming index were evidenced in those formulations without XG or corn cob flour. The results regarding the consistency coefficient (k) and flow behavior indices (n) suggest a possible synergy between XG and flour of corn cob for enhancing the viscosity and pseudoplasticity of dressings in a concentration-dependent manner.

Simulation Analysis of Gas Bubble Formation and Escape in Non-Newtonian Drilling Fluids

In this study, the formation and escape movements of a bubble injected in non-Newtonian drilling fluid through a pore were numerically simulated using a volume of fluid method. The pattern of a single bubble and the pressure and velocity fields of the surrounding liquid phase during the bubble formation were analyzed and compared with experimental results; based on the comparison, the formation and escape properties of the bubble were further studied. In particular, the effects of static shear force, consistency coefficient, and flow behavior index on the growth and escape time of the bubble were analyzed. The results show that, owing to the effect of velocity on the viscosity of a non-Newtonian drilling fluid, the escape time and volume of the bubble increase with an increase in static shear force, consistency coefficient, and flow behavior index. Among the three parameters, the flow behavior index has the greatest effect. This is because the shear disturbance of a bubble to its surrounding fluid during its growth and escape, caused by the shear thinning of a yield-power-law fluid, reduces the fluid viscosity. The shear thinning decreases, and the resistance to the bubble increases as the flow behavior index approaches 1, leading to larger bubble formation times and separation volumes. An empirical formula for predicting the equivalent radius of bubbles considering the liquid yield stress, inertial force, viscous force, and surface tension is established. The average error of predicting the equivalent radius of detached bubble is 0.80%, which can provide a reference for the better study of bubble migration and flow pattern in non-Newtonian fluid.

A Rheological Model for Evaluating the Behavior of Shear Thickening of Highly Flowable Mortar

Neither the modified Bingham model nor the Herschel–Bulkley model can be used to characterize and calculate the performance of shear thickening of highly flowable mortar because of their incalculability of the rheological parameters. A new exponential rheological model was established to solve the characterization and calculation of shear thickening of the lubrication layer (highly flowable mortar) during the pumping of concrete in this paper. This new exponential rheological model has three rheological parameters, namely, yield stress, consistency coefficient, and consistency exponent. They can quantitatively describe the yield stress, differential viscosity, and shear thickening degree of highly flowable mortar. The calculating results of the rheological parameters of the newly established model for the mortars with different compositions showed that the consistency exponent of mortar decreased with the increase of its sand-binder ratio or the dosage of fly ash in the binder. This indicates that the shear thickening degree of mortar decreases. The consistency exponent of mortar initially decreases and subsequently increases with the increase in silica fume content or the dosage of the superplasticizer. It illustrates that the degree of the shear thickening of mortar initially decreased and subsequently increased. These varying patterns were confirmed by the rheological experiment of mortars.

The influence of incubation temperature and starter culture type on physical properties of ayran

In this study, the effects of the incubation temperature and type of starter culture on the physical properties, including graininess and visual roughness, of ayran were determined. Ayran samples were produced from milk inoculated with two different starter cultures (Yo-Mix 410, Yo-Mix 883) and incubated at temperatures of 37 or 45°C, and then stored at 4°C for 15 days. As incubation temperature decreased the number and perimeter of grains and syneresis decreased and the amount of exopolysaccharide (EPS) increased in ayran samples. The high amount of EPS resulted in low syneresis value, the number and perimeter of grains and visual roughness in ayran samples. The apparent viscosity and consistency coefficient values of ayran samples produced from milk incubated at 37°C were higher than those from milk incubated at 45°C. The Power law model was found more satisfactory to describe flow behaviour of all ayran samples. The rheological properties of ayran samples changed with measurement temperature. As the measurement temperature increased from 5°C to 15°C, the apparent viscosity and consistency coefficient values of ayran samples were significantly decreased. The activation energy values for apparent viscosity of ayran samples varied depending on the incubation temperature, type of starter culture and storage period.