TIME in Physics

Analysis of Caffeine Levels in Pacitan Speciality Coffee Using UV-Visible spectrophotometry

Yahya Efendi — 2025-03-10

The Indonesian community, particularly the people of Pacitan Regency, has a deep-rooted connection with coffee. Coffee is a beverage that is almost always served to guests as a customary offering. Pacitan Regency is known for its unique local coffee varieties, namely Kopi Tejo, Kopi Klethik, and Kopi Bima. Coffee contains caffeine, a group of methylxanthine compounds that occur naturally and are classified as xanthine derivatives, belonging to the alkaloid compound group. Caffeine in coffee provides various health benefits when consumed in moderate amounts. This study aimed to analyze the caffeine content in Pacitan’s traditional coffee varieties using UV-Visible spectrophotometry. The analysis revealed that Kopi Tejo contains 0.6040 mg of caffeine per gram, Kopi Klethik contains 0.5547 mg of caffeine per gram, and Kopi Bima contains 0.3213 mg of caffeine per gram.

Identifying Student Misconceptions in Thermodynamics Material

Dea Rahmadani — 2025-03-10

This study aims to identify students' misconceptions in studying thermodynamics. This test includes (1) identifying whether students have misconceptions or not, (2) determining the part of the material where students have misconceptions, and (3) revealing the factors that cause these misconceptions. This study uses a literature review method by analyzing 15 articles and theses as samples. Data were collected through collecting scientific articles and theses that have similar topics related to students' misconceptions in thermodynamics, which were then analyzed. The results of the study showed that several misconceptions were found related to the concepts of work, heat, and energy in the system, thermodynamic processes such as isobaric, isochoric, and isothermal, the laws of thermodynamics, and quantitative interpretations such as PV diagrams. The factors causing these misconceptions are in-depth understanding, abstract nature of the material, lack of practical experience, ineffective teaching methods, and the use of inaccurate textbooks. To overcome this problem, diagnostic methods such as three-level diagnostic tests, clinical interviews, and interactive teaching efforts are considered important in identifying and correcting misconceptions.

Utilization of Pineapple as Essential Oil for Respiratory Disorders: Case Study

Roni Permana — 2025-03-10

This study aims to examine the effectiveness of pineapple (Ananas comosus) Essential oil in alleviating mild respiratory disorders such as cough and shortness of breath. A quasi-experimental method was used, involving two groups: an experimental group receiving therapy with pineapple Essential oil and a control group receiving warm water without oil. The results showed a significant reduction in respiratory symptoms in the experimental group (p < 0.01), while no significant change was observed in the control group. The bromelain content and volatile compounds in pineapple play a role in reducing inflammation and helping to open the airways. These findings indicate that pineapple Essential oil has potential as a natural alternative therapy for mild respiratory problems.

Electric Lamp Light Intensity System Using Blynk Based Internet of Things

Asep Saepurohman — 2025-03-10

Internet of things (IoT) is a requirement that is being developed a lot in smart homes today. Currently, many technology developers create smart devices that can make human work easier. Smart home systems are one of them. In a smart home system, physical devices can communicate via the internet network or other near cable networks to monitor or control devices in a house or building. In order to be able to monitor or control the physical device is integrated with sensors and actuators. One implementation of a smart home is controlling the light intensity of the lights which can be adjusted using the sleader command on Blynk IoT which is installed on the smartphone. The aim of this research is for users to be able to control the light intensity of house lights by using the sleader command on the Blynk IoT application by house occupants. The method used in this research is IoT. IoT-based communication methods allow data exchange between devices. The result of this research is that a lighting control system can be built using Blynk IoT. A feature has been added to this system to control the electrical power that will enter the lamp, so that it can regulate the light intensity according to needs. The success of the system is influenced by the Blynk IoT response when giving a signal to the Node MCU 8266 and the DIMMER response when receiving a command signal from the NODE MCU8266.

Calibration and Signal Processing of MPU6050 Sensor to Improve Navigation Stability of Autonomous Underwater Vehicle (AUV)

Permono Adi Putro — 2025-03-10

A stable and accurate navigation system is crucial for the operation of Autonomous Underwater Vehicles (AUVs), especially in underwater environments where GPS signals are unavailable. This study aims to enhance AUV navigation performance by optimizing the use of a low-cost inertial sensor, the MPU6050, through calibration and signal processing techniques. The methodology includes reading raw data from accelerometer and gyroscope sensors, performing static calibration to reduce bias and noise, applying Fast Fourier Transform (FFT) for signal analysis, and implementing digital filters such as low-pass and high-pass filters. The raw data reveal significant deviations due to gyroscope bias and accelerometer noise. Static calibration effectively reduces systematic errors, although residual biases remain. FFT analysis identifies dominant frequency components in each axis, while digital filtering helps eliminate irrelevant frequency noise. Precision testing demonstrates that the sensor produces relatively stable data post-calibration, with the Z-axis showing higher deviation compared to the X and Y axes. The combination of calibration and signal processing methods significantly improves the data quality and reliability of the MPU6050 sensor. This research contributes to the development of more efficient and low-cost AUV navigation systems and supports the broader application of simple IMU sensors in underwater exploration and maritime technologies.