Analysis of rotating object using video tracker

The purpose of this paper is to show the use of video tracker to analyze circular motion. Measurement of circular motion such as angular velocity and angular acceleration is not easy to do observation and measurement directly. Through the video tracker tool, the analysis of speed and rotation acceleration becomes easier. The rotating object used as a research object is a spinner fidget. The initial velocity of the rotation depends on the pull of the finger on the spinner. The duration of rotating spinner fidget depends on the inertia and attenuation that occurs. Camera position and resolution of the camera greatly determine the data on the video tracker. The standard camera capability of 30 frames per second is less capable of capturing objects that rotate with high resolution.

Evaluation of performance of POAMA forecast system in predicting monthly precipitation over Indonesia

Hindcast produced by a model used in a numerical model-based seasonal prediction system is an essential part in the operational seasonal prediction system. This paper is aimed at evaluating the performance of POAMA model from the climatological aspect. The data used in this research are obtained from three variants of POAMA m24 model. The results show that the annual cycle of climatological rainfall averaged over Indonesia is well simulated by POAMA m24, although there is a dry bias in the rainy season and a wet bias in the dry season. From those three variants, m24b model has a relatively low variation of bias against lead-time compared with the m24a and m24c models due to the implementation of flux correction scheme in m24b model. However, the performance of POAMA m24 model with a resolution of T24 is inferior to CFSv2 with a resolution of T126 in simulating the spatial pattern of rainfall over Indonesia. Beside model resolution, convection scheme used in a model also has significant influence. This can be seen from the resemblance between the spatial pattern of total rainfall and that of convective rainfall. Thus, the horizontal resolution of a model and a suitable convection scheme for Indonesian region are the two factors that must form important consideration in the development of Indonesian seasonal prediction system.

The role of cooperative learning with team assisted individualization to improve the students’ self proficiency

The importance of learning mathematics can not be separated from its role in all aspects of life. This research aims to analyze the achievement of the students’ self-proficiency who are taught by using cooperative learning with Team Assisted Individualization (TAI) and conventional learning. Students need to possess self-proficiency ability well so that they could have confidence that they are capable of confronting and of solving their daily life problems in general or mathematical tasks in particular. The population in this research was students of Statistics study program at one of public universities in Makassar. The sampling technique used in this research was purposive sampling, while the instrument used was self-proficiency scale (SPr) which has been validated. The data were analyzed by using parametric and non-parametric statistics. The result of this research is that the achievement of the students’ self-proficiency who are taught by using cooperative learning with TAI is better than students who are taught by using conventional learning.

Effects of air pressure changes on gamma linear attenuation coefficient in the air

The measurements of gamma linear attenuation coefficient in the air at variance air pressure has been done. The measurements were performed to determine the effects of air pressure changes on gamma linear attenuation coefficient in the air. The measurements were used Co-60 as the gamma radiation source and LND 72 Geiger-Muller as the radiation detector in a room with 18oC room temperature and 68% air humidity. The linear attenuation coefficient value was calculated according to Lambert-Beer law. From the measurement, we obtained the attenuated gamma intensity in the air at air pressure variation. The unattenuated gamma intensity was determined by making a linear fit function of the attenuated gamma intensity data. From the calculation, It was found that the value of gamma linear attenuation coefficient in the air increases with the increasing of air pressure.

Application of threshold vector error correction model (TVECM) in describing adjustment of interest rate of working capital credit to BI rate movement

Knowledge about bank behavior in adjusting the interest rate to BI rate movement is important not only for debtors to make a decision to borrow money, but also for government to know whether BI rate as a monetary policy tool success in influencing the movement of interest rate. The approach used for analyzing the data in this paper is TVECM. The data used in this paper are interest rate of working capital credit of conventional bank and BI rate of January 2008–July 2016. Bank is more agressive in correcting the disequilibrium by increasing the interest rate of working capital credit than decreasing it. Interest rate of working capital credit is significantly adjusted by bank approximately 64.95% of its disequilibrium when the disequilibrium is lower than 0.96. When it is between 0.96 and 0.76, interest rate of working capital credit will be adjusted approximately 11.87% of its disequilibrium.When it is higher than 0.76, interest rate of working capital credit will be adjusted approximately 11.88% of its disequilibrium. Moderate interest rate of working capital credit based on BI rate consideration is between 1.74 BI rate –0.96 and 1.74 BI rate +0.76. According to the selection criteria values, TVECM is better than VECM and VAR in modeling relationship between BI rate and interest rate of working capital.

On precipitation of struvite (MgNH4PO4.6H2O)

Excessive input of N and P into water bodies causes eutrophication which leads to deterioration of aquatic evironments and has adverse effects naturally and economically. It is therefore urgent to remove N and P from wastewater prior to disposal into inland and coastal waters. Among the various removal methods, controlled struvite precipitation is preferred. Struvite (MgNH4PO4.6H2O) precipitates uncontrollably under the specific conditions producing a scale deposit causing persistent problems in industries and wastewater treatment plants. The scale deposit clogs the piping system and impair plant equipment. On the other hand, thanks to its composition and properties, struvite is a potential fertilizer. In medical field, struvite is a common component of kidney stones. A number of process parameters govern the struvite precipitation. This paper briefly presents these parameters: pH, molar ratios, temperature, mixing, and presence of foreign ions. pH level is considered as the most important variable affecting the precipitation of struvite and the pH level: 9.5 to 10.5 is seen as the optimum. For an effective precipitation the molar ratios of the struvite components, i.e. Mg:N:P should be at least unity. With regard to struvite solubility, the effect of temperature, in the range of 21oC to 49oC, is conflicting, which is probably due to different experimental conditions. Whilst agitation is not regarded as a decisive parameter, the influence of foreign ions, notably divalent metal ions, on struvite morphology and change of crystal phases is significant.

Antibacterial activity of the dregs of green tea leaves (Camellia sinensis L.) on Staphylococcus epidermidis as causes of acne

The dregs of green tea leaves have not been used until today, it is still considered as a waste that is not useful. It is known that the dregs of the green tea leaves contain Epigallocatechin-3-gallate (EGCG), which is quite high. EGCG has benefits as an antibacterial. The long-term goal of this research is the application of cosmetic preparation products from the dregs of green tea leaves that have effectiveness, stability and high economic value. The specific target of this research is to get the dose and concentration of the dregs of green tea leaves in a stable and effective way as anti-acne against Staphylococcus epidermidis (S. epidermidis). The search of the dregs of green tea leaves is by techniques of infundation of liquid fractions with ethyl acetate, identification of EGCG compound by using HPLC, antibiotics test against S. epidermidis was conducted by diffusion method. The results showed that the content of EGCG of the dregs of green tea leaves was 21.325% w/w, and the concentration of 1% of the dregs of green tea leaves can inhibit the growth of S. epidermidis well.

A simple parameterization for tsunami run-up prediction

The linear shallow-water approximation is commonly used to describe tsunami propagation, where the wave is assumed as a long surface gravity wave. The evolution of wave height during its propagation from offshore to onshore is a classic problem. When arriving at a shoreline, the increased wave height causes severe destruction on infrastructures and fatalities. This problem has then been an important issue within the context of disaster risk reduction as it gives rise to the importance of tsunami run-up prediction. Using maximum run-up data from past events, we tested the applicability of the Green’s law based on shoaling only to calculate run-ups and found that the basic Green’s law was in doubt. Then, we examined energy density conservation involving refraction effect but no dissipation and derived a simple formula for parameterizing run-up height. Detailed descriptions on factors affecting run-ups, such as complex bathymetry and topography are not yet considered in the current study. The aim of this study is therefore to determine whether the modified Green’s law is applicable for tsunami run-up prediction using local water depths as external parameters and ray spacing widths in the normal direction of wave fronts related to refraction. The results are consistent with the measured run-ups, where approximately 70% of total points of observations confirm the modified Green’s law with a reasonable accuracy.

Accurate local magnitude prediction for small to moderate earthquakes using rapid calculations of P-wave dominant period

This study examines mechanisms of rapid and accurate determination of local magnitude Mpd for small to moderate events that occurred in West Sulawesi and Central Sulawesi using direct procedures and calculations of the dominant period Td of P-waveforms. Secondary data were collected from Webdc3, comprising earthquake magnitudes in the regions of interest during 2008-2015 measured in MW. The study focuses on earthquake size estimates for local events as a parameter through simple evaluation of a linear equation relating Td to MW. For all the events considered, empirical formulas derived from the random data for estimating the size are, respectively, Mpd = (Td + 6.6799)/1.5199 for West Sulawesi and Mpd = (Td + 3.3648)/0.8464 for Central Sulawesi. Each was used to recalculate events in the two regions. The results were compared to the reference provided by the Global CMT catalog. The results are consistent with the reference having a standard deviation of up to 0.2, showing evidence of no significant difference in magnitude determination between the method proposed in the current study and that of the Global CMT. This suggests that rapid and accurate magnitude determination is best predicted by the empirical formula developed for each region in this study for future use of disaster risk reduction program.