Volume 12 Number 1 (January )

Combined effects of ultrasound power and DO on nitrogen removal in a low-intensity ultrasound (LIU)-assisted sequencing batch biofilm reactor

Ultrasonication is a sustainable biophysical technology used in sludge treatment. Studies show it enhances microbial activity and pollutant removal from wastewater under optimal conditions. This study examines ultrasonic irradiation's effect on nitrogen removal efficiency and extracellular polymeric substances (EPS) formation in Sequencing Batch Biofilm Reactors (SBBRs). Four reactors with different ultrasonic powers (0 W, 180 W, 270 W, and 360 W) and dissolved oxygen (DO) concentrations were tested to explore the interaction between ultrasonic treatment and nitrogen transformation. Results show that moderate ultrasonic power (180 W and 270 W) significantly improves ammonia nitrogen and total nitrogen (TN) removal rates, reaching up to 99.4% and 91.7% at a 2 mg/L DO concentration. Higher power (360 W) increased EPS production, especially tightly bound EPS, enhancing biofilm stability and microbial protection, but did not improve nitrogen removal. Thus, balancing ultrasonic intensity and DO is crucial for optimal performance. Microbial analysis indicates ultrasonic treatment alters microbial diversity, promoting species and aiding nitrification and denitrification. This study shows that controlled ultrasonic irradiation can enhance SBBR efficiency by adjusting microbial activity and biofilm structure, improving wastewater treatment.

Application of Humic Acid and Mulch Dose on Corn (Zea mays L) Yield

Bama Wida Pratama, Luluk Sulistiyo Budi, Indah Rekyani Puspitawati

This research aims to determine whether there is an interaction between the use of humic acid and mulching on the growth and production of corn plants, the effect of humic acid on the growth and production of corn plants and the effect of the use of mulch or mulching on the growth and production of corn plants. This study used a Randomized Block Design (RAK) with 3 replications in Giripurno Village, Kawedanan District, Magetan Regency. The first factor studied was humic acid (A) consisting of 3 treatments, namely doses of 0 Kg / Hectare, 10 Kg / Hectare, 20 Kg / Hectare and the second factor was mulch (M) consisting of 3 treatments, namely without mulch, plastic mulch, straw mulch. The parameters observed included plant height, stem diameter, number of cobs, weight of wet cobs with husks, weight of wet corn cobs without husks, weight of 1000 grains, number of rows, number of seeds, dry weight without husks, weight of dry husked corn, number of leaves, leaf area. There is interaction with plants on the parameters of yield, namely the weight of wet cobs with husks, weight of 1000 grains, and number of rows because the nutrients in humic acid can provide benefits to the yield of corn plants. The absence of interaction on the parameters of plant height 53 HST, stem diameter, number of cobs, weight of wet cobs without husks, number of seeds, dry weight of whole cobs, weight of dry kernels, number of leaves, leaf area is caused by insufficient dosage and short sample observation time.

New Weighted Taylor Series for Water Wave Energy Loss and Littoral Current Analysis

Syawaluddin Hutahaean

This paper presents a more systematic formulation of the weighted Taylor series, resulting in a more accurate determination of the weighting coefficient. The weighted Taylor series is derived by truncating the Taylor series to the first order and assigning weighting coefficients to the first-order terms, which reflect the contribution of higher-order terms. The resulting weighted Taylor series is applied to the analysis of wave constant equations in deep water, including wavelength and wave period, which are primarily governed by the Kinematic Free Surface Boundary Condition. The input for these wave constant equations is the wave amplitude. Using these wave constant equations, a shoaling-breaking model is developed, accounting for wave energy loss. The lost wave energy is then utilized to derive the radiation current equation, which subsequently leads to the formulation of the littoral current equation.

Implementation of the K-Means Clustering Algorithm to Determine the Promotion Strategy of Institut Agama Kristen Negeri Tarutung

Frainskoy Rio Naibaho, Bambang TJ Hutagalung, Risden Anakampun

This research aims to determine the strategy for recruiting new students at IAKN Tarutung. Currently, competition between state and private universities in accepting new students is increasingly competitive. This is proven by the decreasing trend of prospective students registering at IAKN Tarutung, especially in the Cultural and Religious Tourism study program (as the research sample). Based on data from active students in The Cultural and Religious Tourism Study Program, the K-Means algorithm can be implemented to assist decision-making in determining effective promotional targets for the following year. The results of the research show that data processing for students from the classes of 2021, 2022, and 2023 shows different trends based on Criterion 1 (high school or equivalent vocational school graduates), Criterion 2 (student achievement at their school of origin), and Criterion 3 (community economic ability). Based on data from Criterion 1, criterion 2, and criterion 3, it is stated that promotional strategies must continue to be carried out in all high schools or equivalent vocational schools (public and private) and provide scholarships for prospective Cultural and Religious Tourism study program who are outstanding or economically disadvantaged.

Dengue Hospitalizations in the state of Pará over the last decade: An ecological study

Introduction: Dengue is an arboviral disease transmitted by the mosquito Aedes aegypti and represents a public health problem in tropical and subtropical countries, especially in regions with limited access to healthcare services. However, the literature lacks studies on dengue-related hospitalizations in Pará, which could support more effective health policies for controlling and reducing the disease in the state. Objectives: To evaluate the temporal trend and compare dengue hospitalizations in Pará with other states in the Northern Region, outlining the epidemiological profile. Methods: This is a descriptive ecological epidemiological study using data from the Hospital Information System (SIH) from 2014 to 2023, referring to hospitalizations due to dengue (ICD C32.1). The analyzed variables included year and month of care, number of hospitalizations, hospitalization rate per 100,000 inhabitants, sex, age, and type of care. Statistical analysis was performed using Simple Linear Regression, the Kruskal-Wallis test, and Dunn’s post-hoc test, using Statistics Kingdom software. Results: A total of 13,956 hospitalizations for dengue were recorded in Pará during the study period. A reduction trend of 2.88 hospitalizations per year was observed (p < 0.005, B1 = -2.88, 95% CI [-4.62, -1.14], R = -0.80). The Kruskal-Wallis test, followed by Dunn’s post-hoc test, showed that Pará did not present a significantly different hospitalization rate compared to the other states. In the epidemiological profile, females had a higher number of hospitalizations (n=7,201) compared to males (n=6,755). The adult hospitalization rate was 4.7 times higher than that of the elderly and 1.6 times higher than that of children and adolescents. Additionally, 92.9% of hospitalizations occurred on an emergency basis. Conclusion: Pará has shown a reduction in hospitalizations due to dengue over the years. Women and adults are the most affected, with the majority of hospitalizations occurring on an emergency basis. The results suggest that this decrease may be due to more effective preventive strategies, underreporting of cases, or reduced exposure to risk factors among the population of Pará. Future studies are needed to confirm these hypotheses and guide more targeted interventions.