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Covid-19 entered Indonesia in March 2020, which had an extraordinary impact on all aspects of life. The real impact is the economic and social sectors. Various efforts and policies from the Indonesian government were made to suppress the increase in the rate of Covid-19 cases. The spread of Covid-19 cases in Indonesia has been evenly distributed in various provinces, one of which is East Java. East Java has 38 districts/cities, where the case of each district is different, there are green, yellow, red, and black zones. To find out the pattern of spread of each district/city zone, clustering is used. The method used in this study was to use the hybrid method of clustering with K-means and classification with its algorithm Decision Tree. The purpose of this study to prepare mitigation measures to inhibit the rate of spread of Covid-19 in East Java Province. The variables used include the number of positive, the number of dead, the number of recovered, the number of suspects, and the number of probable. With this grouped data, it is expected to help make the right decision in reducing the spread and minimizing the number of positive patients. Based on the results of the study, there will be cluster results, namely 7 very high-risk areas (C0), 1 high risk district (C1), 29 moderate risk districts (C2), and 1 low-risk district (C3). It also has a validity index level of 0.356 as measured by the Davies-Bouldin Index.

Coating film thickness is one of many important aspects in the development of Quartz Crystal Microbalance (QCM) for chemical sensors and biosensors. The coating layer is utilized as a matrix layer for the bio-sensitive molecule or as a sensitive layer. Also, the coating thickness is an important physical parameter, which determines the sensitivity and stability of the QCM sensor. Commonly for the thin film or glassy film, the Sauerbrey equation was used to calculate the film thickness. However, the method is inaccurate for a rubbery film. In this study, a non-destructive method was developed to measure the thickness of a transparent layer deposited on QCM using the interferometry method. This interferometry method uses the principle of coherent light interference between the initial laser beam and the one that has passed through a transparent layer. In this work polystyrene film which is known as a glassy film was used. The results of this study show that the interferometry method can be used to measure the thickness of the polystyrene layer deposited on the QCM sensor, as a non-destructive measurement method. These results are validated by calculations from the Sauerbrey equation, in calculating the thickness of polystyrene-based on changes in the frequency of the QCM sensor, which is 0.421 micrometers.

Ultraviolet Light Emitting Diode (UV LED) is becoming popular, especially during the Covid-19 pandemic. UV LED has a specific wavelength with relatively narrow bandwidth, especially the one that has a shorter wavelength. On the other hand, UV LED has advantages in its low power consumption, compact size, and longer lifetime. This work shows that a wider bandwidth can be elicited by combining multiple UV LED sources. We have measured several low-cost UV LED, which is used as a germicidal lamp using a portable spectrometer that can detect a wavelength from 200 nm to 850 nm. The combined UV LED spectrum light ranges from 254 nm UVC to 400 nm UVA. The light spectrum produced by the LED shows a form of the Gaussian distribution model. Some LEDs have a peak wavelength at UVC around 270nm, and LEDs have a peak wavelength around 400nm at UVA. We can conclude that the low-cost UV LED can be used as a light source for portable or field spectrometers for specific wavelength.

Banyuwangi is a district in East Java province in Indonesia which is known as the Rice Barn of East Java. Banyuwangi region is facing challenges such as population growth, increased consumption of rice, reduced agricultural land because there are several agricultural land used as non-agricultural land. Because of there are production it is not enough from objects with just one period, therefore the use of data panels is one solution because it considers the time period and objects needed to determine the factors that influence rice production. In this study the analysis to model panel data from rice production in Banyuwangi was Generalized Additive Mixed Model (GAMM) and Generalized Estimating Equation GEE. In general GAMM as a mixed model, contains random effects so that this model is very useful when inference about individual differences is a major interest. While GEE is a model used to provide the population averaged effect. GEE also has the feature of smoothing natural cubic spline and B-spline so that it can be called GEE (+ NS/BS) which aims to improve the goodness of fitting a model. In this study, we want to see the effect of the total rainfall, harvest area, and population density on rice production. we also develop GAMM in the form of web interface to make users easier to analyze data using GAMM through http://statslab-rshiny.fmipa.unej.ac.id/RProg/MSD/.

Spectrophotometer is modern analytical instrument for analysis the amount of substance based on the color change. However, for high school laboratory practice, only few schools had this instrument for chemical analysis. There are many studies reported the use of daily life electronic for colorimetric analysis such as smartphone, scanner and digital camera. This work demonstrated the used of document scanner for colorimetric glucose determination for easy learn the daily life instrument as analytical device. The color detection was based on the reaction of glucose with glucose oxidase enzyme to produce H2O2. The H2O2 was then reacted with TiOSO4 to produce yellow color. The color formation was captured with a document scanner and the digital image was analyzed using ImageJ software. The result of the used of document scanner showed Horwitz Ratio of 0.40, recovery of 98.4%, linear responses from 0.5 mM to 3.0 mM (r = 0,9989), limit of detection of 0.15 mM and limit of quantification of 0.40 mM.

Aluminium nanoparticles (Al NPs) have been synthesized using electrochemical method. The synthesis was conducted by electrolysis of aluminium metal in a sodium citrate solution as an electrolyte solution. Formation of Al NPs was investigated on the variation of potential (5-50 V), concentration of electrolyte solution (0.02-0.42 M), and electrolysis time (15-75 minutes). The obtained product was characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Energy Dispersive X-Ray (EDX), and UV-Vis Spectrophotometer. XRD pattern indicate that the obtained product was aluminium nanoparticles. The result show that the size of Al NPs were 56-63 nm with the Al compositions of 7.08%. The optimum condition was reached at 40 V with 0.18 M sodium citrate solution during 45 minutes electrolysis process. The plasmon band peak was found at 234 nm. In this condition Al Nps is more stable.

Unpredictable rainfall changes can affect human activities, such as in agriculture, aviation, shipping which depend on weather forecasts. Therefore, we need forecasting tools with high accuracy in predicting the rainfall in the future. This research focus on local forcasting of the rainfall at Jember in 2005 until 2016, from 77 rainfall stations. The rainfall here was not only related to the occurrence of the previous of its stations, but also related to others, it's called the spatial effect. The aim of this research is to apply the GSTAR model, to determine whether there are some correlations of spatial effect between one to another stations. The GSTAR model is an expansion of the space-time model that combines the time-related effects, the locations (stations) in a time series effects, and also the location it self. The GSTAR model will also be compared to the ARIMA model that completely ignores the independent variables. The forcested value of the ARIMA and of the GSTAR models then being combined using the ensemble forecasting technique. The averaging and stacking method of ensemble forecasting method here provide us the best model with higher acuracy model that has the smaller RMSE (Root Mean Square Error) value. Finally, with the best model we can offer a better local rainfall forecasting in Jember for the future.