USU-IR Repositori Institusi Universitas Sumatera Utara
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Improving Energy Efficiency in Electric GoKart through the Implementation of a Regenerative Braking System
No full textThis study aims to analyze the improvement of energy efficiency in an electric go- kart through the implementation of a regenerative braking system. In conventional braking systems, the kinetic energy of the vehicle during deceleration is dissipated as friction, which is converted into heat, resulting in energy loss from the battery. Therefore, a regenerative braking system is applied to convert this kinetic energy into electrical energy and store it back into the battery.
The electric go-kart used in this study is equipped with a 4000 W BLDC motor, a Votol EM-150 controller, and a 72 V 39 Ah lithium-ion battery. Testing was conducted at speed variations of 30 km/h, 40 km/h, 50 km/h, and 60 km/h under both no-load and loaded conditions. The analyzed parameters include energy consumption, regenerated energy, and overall system energy efficiency. The experimental results indicate that the efficiency of regenerative braking increases with increasing vehicle speed. Under loaded conditions, the highest efficiency was achieved at a speed of 60 km/h with a value of 10.87%, while at 30 km/h the efficiency was only 7.46%. Meanwhile, under no-load conditions, the system demonstrated significantly better performance, achieving an efficiency of 94.59% at 60 km/h compared to 50% at 30 km/h. Based on these results, it can be concluded that the regenerative braking system operates most effectively at higher speeds, particularly under no-load conditions, due to the greater amount of kinetic energy available for regeneration. The implementation of this system has been proven to improve energy efficiency, reduce wasted energy, and potentially extend the driving range of the electric go- kart without increasing battery capacity.96 PagesSkripsi Sarjan
Diversity of Freshwater Fish Species in the Waters of the Sei Belumai River, Tanjung Morawa, Deli Serdang
No full textThe Belumai River is located in Tanjung Morawa District, Deli Serdang Regency, North Sumatra. Households living along the banks of the Belumai River use the river water directly and indirectly for daily needs such as drinking water, bathing, washing, and toilets, agriculture, freshwater fisheries, and water recreation (bathing). The purpose of this study was to determine the diversity of freshwater fish species found in the Sei Belumai River, Tanjung Morawa, and to determine how the diversity of freshwater fish species is influenced by the water quality of the Sei Belumai River. This research was conducted from October to December 2024. The results obtained a total of 109 fish species at each station, 8 species, 5 families, and 4 orders. Abundance (K) values ranged from 4.04 ind/m2 to 14.90 ind/m2. Diversity index values ranged from 0.93 to 1.66, evenness index from 0.63 to 0.85, and dominance index from 0.21 to 0.48. Principal component analysis values showed that clarity, pH, temperature, BOD, total nitrogen, current, and depth were negatively correlated with fish diversity and abundance. Meanwhile, TDS, DO, temperature, and phosphate showed a positive correlation with fish diversity and abundance. The correlation values and interpretation ranged from 0.162 to 976, with categories ranging from very weak to very strong.60 pagesSkripsi Sarjan
The Impact of Seawater Intrusion on The Characteristics of Bore Well and Conventional Well Water in Dusun 1 Village Pantai Cermin Kanan, North Sumatra
No full textSeawater intrusion is a serious threat to groundwater quality in many coastal areas,
particularly in Indonesia, an archipelagic country that is highly vulnerable to rising
sea levels and excessive groundwater extraction. This study aims to examine the
impact of seawater intrusion on the quality of borehole and conventional well water
in Dusun 1 Pantai Cermin Kanan Village, North Sumatra. Sampling was carried out
at five borehole well points (10–15 m deep), five conventional well points (4–12 m),
and seawater as a comparison. The measured parameters included electrical
conductivity (EC), pH, total dissolved solids (TDS), salinity (Na content), and
manganese (Mn) levels. The results show that borehole well water generally has
better quality with a near-neutral pH (6.58–7.27), low TDS (53–75 mg/L), and
moderate salinity (25–36 g/L). In contrast, conventional well water tends to be more
acidic (6.25–6.62), has higher TDS (74–105 mg/L), and at several points shows a
spike in salinity and very high Mn levels despite being more than 2,000 m from the
coastline. These findings indicate that seawater intrusion significantly affects
shallow, less-protected conventional wells, while deeper borehole wells, although
relatively safer, still show signs of saltwater seepage. This study emphasizes the
importance of regular management of groundwater extraction and improving well
construction standards to control seawater intrusion and protect the health of the
community and the agricultural sector in coastal areas68 PagesSkripsi Sarjan
The Effect of Using a Mixture of Cattle Faeces and Coffee Husks as Bokashi on the Productivity of Mini Elephant Grass (Pennisetum purpureum cv. Mott)
No full textThe availability of quality forage remains an issue in Indonesian livestock farming. Dwarf elephant grass (Pennisetum purpureum cv. Mott) was chosen because it has high productivity and nutritional content. This study aims to determine the effect of using cattle manure bokashi and coffee husk on the growth and productivity of dwarf elephant grass (Pennisetum purpureum cv. Mott). The research was conducted at the Experimental Field of the Faculty of Agriculture, Universitas Sumatera Utara, from May to August 2025. This research was conducted experimentally using a completely randomized design (CRD) with five treatments: P0 = Without cow manure bokashi and coffee husk fertilizer, P1 = Given cow manure bokashi and coffee husk fertilizer 200 g/polybag, P2 = Given cow manure bokashi and coffee husk fertilizer 400 g/polybag, P3 = Given cow manure bokashi and coffee husk fertilizer 600 g/polybag, P4 = Given cow manure bokashi and coffee husk fertilizer 800 g/polybag, each treatment had 4 replicates. The growing medium for mini elephant grass in this study was ultisol soil, which was chosen because it has low nutrient content, allowing the effects of bokashi fertiliser application to be clearly observed. The research parameters were plant height, leaf length, leaf width, number of tillers, fresh weight production, and dry weight. The bokashi mixture of cow manure and coffee husks in this study contained 5.78% K, 1.41% N, 0.70% P, 35.78% organic C, and 25.37% C/N. The results of the study showed a very significant effect on plant height, leaf length, leaf width, number of tillers, fresh weight production, and dry weight, where increases in each parameter were in line with the addition of bokashi dosage. The best combination was shown in treatment P2 with a bokashi fertiliser dose of cow manure and coffee husks of 400 g/polybag. This indicates that bokashi fertiliser made from cow manure and coffee husks is suitable for use as organic fertiliser to increase the productivity of mini elephant grass.69 PagesSkripsi Sarjan
The Perspective of Migrant Communities in Medan City and the Sihonongan Village Community in Paranginan District Regarding the Phenomenon of Marriages Between the Simatupang Clans (Sianturi-Siburian)
No full textThis study aims to understand the perspectives of the people of Medan City and Paranginan Village on the phenomenon of consanguineous marriage within the Simatupang (Sianturi-Siburian) clan. In Toba Batak customs, consanguineous marriage is traditionally considered a violation of the Dalihan Na Tolu kinship system, as it is viewed as marriage between people of the same descent or blood. Nevertheless, this practice is still found in certain communities, whether for reasons of love, limited partners, or close family ties. This study uses a descriptive qualitative approach, with data collection techniques through in-depth interviews and observations of the migrant community in Medan City and the community in Paranginan Village. The analysis was conducted using Emile Durkheim's sentiment theory, which explains that customary rules and prohibitions on consanguineous marriage are part of the social facts and collective sentiments that bind society. These social facts function to maintain social order and harmony, while collective sentiments form the basis for the emergence of solidarity among clan members. The results of the study indicate differences in perspectives on the prohibition on consanguineous marriage. Migrant communities in the city tend to maintain the prohibition as a symbol of respect for ancestors and traditional identity amidst a pluralistic modern life. In contrast, the Paranginan village community demonstrates a more adaptive attitude, continuing to hold traditional ceremonies as a form of social legitimacy, ensuring that consanguineous marriages remain accepted within the customary framework. This phenomenon demonstrates a shift in values and forms of social solidarity. Rural communities reflect mechanical solidarity, emphasizing togetherness, while urban communities demonstrate organic solidarity, affirming traditional identity amidst modernity. Thus, the phenomenon of consanguineous marriages in Toba Batak society is not simply a violation of customary law, but rather a manifestation of social and moral dynamics that demonstrate the community's efforts to balance tradition, identity, and social change within the Dalihan Na Tolu value system.Skripsi Sarjan
Inflammatory Markers and Diabetic Foot: Their Role in Type 2 Diabetes Patients at H. Adam Malik Hospital
No full textBackground
Diabetic foot is a severe complication of type 2 diabetes mellitus, resulting from chronic hyperglycemia, vascular disorders, neuropathy, and infection. Inflammatory markers such as C-Reactive Protein (CRP), Erythrocyte Sedimentation Rate (ESR), fibrinogen, and D-dimer reflect inflammation and coagulation that worsen diabetic foot conditions. However, data from the local population in Medan remain limited.
Methods
This cross-sectional study was conducted at H. Adam Malik General Hospital, Medan, between May and June 2025. The inclusion criteria in this study were patients over 18 years old, either newly or previously diagnosed with type 2 diabetes mellitus, with or without diabetic foot complications (grade II–V), who were hospitalized at Adam Malik Hospital. The exclusion criteria included patients with a history of other chronic diseases such as HIV, malignancies, autoimmune disorders, and other infections; patients taking anticoagulant drugs, NSAIDs, steroids, hormonal therapy, or immunomodulators; pregnant women; and patients with incomplete medical records. Demographic data, HbA1c levels, and concentrations of CRP, ESR, fibrinogen, and D-dimer were analyzed using appropriate statistical tests based on data distribution, with statistical significance set at p<0.05
Result
A total of 63 patients were included in the analysis. There was a significant association between body mass index (BMI) and diabetic foot (p<0.05) but no significant associations were found between age, sex, or HbA1c levels and the occurrence of diabetic foot. However,Levels of CRP, ESR, fibrinogen, and D-dimer were significantly higher in patients with diabetic foot compared to those without (p=0.001). CRP levels were also significantly associated with the severity of ulcers based on the Wagner classification.
Conclusion
Inflammatory markers including CRP, ESR, fibrinogen, and D-dimer were significantly elevated in patients with diabetic foot, with CRP emerging as the strongest predictor of wound severity. Monitoring these biomarkers is crucial for risk assessment and management of diabetic foot in patients with type 2 diabetes mellitus.108 PagesTesis Magiste
Pre-Design of a Plant for Producing Paraxylene from Toluene and Hydrogen Using The Tatoray Process with ZSM-5 Catalyst, Production Capacity of 200,000 Tons/Year
No full textThe preliminary design of a para-xylene production plant from toluene and
hydrogen has a production capacity of 200,000 tons per year and operates for 330
days annually. The raw materials required to achieve this production capacity are
150,793.710 kg/h of toluene and 9,893.075 kg/h of hydrogen. The overall process
in this plant design consists of three main stages, namely feed preparation, reaction,
and purification. In the feed preparation stage, the mixture of toluene and hydrogen
gases is passed through a compressor to increase the pressure to 24 atm and then
heated in a furnace to 425 °C before being fed into the reactor. In the reaction stage,
the disproportionation reaction takes place inside a fixed-bed multitube reactor
under conditions of 425 °C and 24 atm. The reaction employs ZSM-5 catalyst with
a total mass of 18,705.574 kg, distributed collectively within 1,091 reactor tubes.
In the purification stage, two distillation columns are used to separate toluene and
benzene from the xylene mixture, followed by an adsorption process to obtain high
purity para-xylene. The main product, para-xylene, is stored in a storage tank at 32
°C, while benzene and mixed xylene are stored at the same temperature as by
products, and toluene is recycled back to the reactor feed. The plant is planned to
be located in Cilegon City, Banten Province, Indonesia, specifically in Area G4,
Krakatau Industrial Estate Cilegon (KIEC), with a total land area of 6.680 m². The
company will operate as a Limited Liability Company (PT) using a line and staff
organizational structure, employing 196 workers. The economic evaluation of the
para-xylene production plant from toluene and hydrogen shows a total capital
investment of Rp7.787.925.224.416, total production cost of Rp7.045.094.570.500,
annual sales revenue of Rp8.810.798.334.147, and net profit after tax of
Rp1.363.476.446.288. The economic feasibility analysis yields a profit margin
(PM) of 15.48%, break-even point (BEP) of 48.08%, return on investment (ROI) of
17.51%, return on network (RON) of 35,02%, pay-out time (POT) of 5 years and 9
months, and an internal rate of return (IRR) of 16,658%. Therefore, the para-xylene
production plant from toluene and hydrogen via disproportionation process is
economically feasible to be established.591 PagesSkripsi Sarjan
Analysis of Factors Related to Farmers’ Decisions in Selling Bokar (People’s Rubber Processing Material) to Middlemen
No full textThis study aims to analyze the relationship between bokar prices,
production quantity, convenience, and family ties with farmers' decisions to sell
bokar to middlemen. The analytical method used in this study is the nonparametric Spearman’s Rank correlation test. The results showed that Bokar
price has a positive and significant relationship with farmers' decisions to sell to
middlemen, with a correlation coefficient of 0.623 and a significance level of 0.00.
Production quantity shows a correlation coefficient of 0.657 with a significance of
0.00, indicating a positive and significant relationship with a moderate level of
correlation. Convenience in the sales process also has a positive and significant
relationship with farmers' decisions, with a correlation value of 0.684 and a
significance of 0.00. Family ties also show a positive and significant relationship
with farmers’ decisions, with a correlation value of 0.701 and a significance level
of 0.00. These findings highlight the importance of government policies in
creating alternative, competitive marketing systems with stable prices, so that
farmers do not remain dependent on middlemen.78 PagesSkripsi Sarjan
Comparison of the Diagnostic Value of Calretinin and S100 as Immunohistochemical Markers in Establishing Hirschsprung Disease Diagnosis at RS Adam Malik Medan
No full textBackground: Hirschsprung Disease (HSCR) is a congenital disorder due to neural crest cell migration failure, causing ganglion cell absence in the distal bowel segment and functional obstruction with incidence 1:5000 live births, more common in males. Conventional HE histopathology as gold standard is often limited by immature ganglion cells or thin submucosa, requiring immunohistochemistry markers calretinin (negative in aganglionic segments) and S100 (highlights nerve trunk hypertrophy).
Methods: Observational analytic cross-sectional study on 64 patients <18 years with rectal HSCR biopsy at RS Adam Malik (2022-2025), consecutive sampling. HE, calretinin, and S100 slides evaluated by researcher and two pathologists; analysis included descriptive statistics, chi-square (p<0.05 significant).
Results: Of 64 subjects, 41 (64%) were male and 34 (53.1%) aged <1 year. HE+calretinin confirmed HSCR in 45 (70.3%) cases, HE+S100 in 55 (85.9%) cases (p=0.002). Calretinin showed sensitivity 97.7%, specificity 89.4%, AUC 0.89; S100 demonstrated sensitivity 78.1%, specificity 66.6%, AUC 0.88.
Conclusion: Calretinin exhibits superior diagnostic value (higher sensitivity/specificity) compared to S100, supporting its use as single cost-effective immunohistochemistry marker complementing HE for accurate HSCR diagnosis, particularly in neonates.54 PagesTesis Magiste
Comparison of the Boston Carpal Tunnel Syndrome Questionnaire Diagnostic Test with the Kamath and Stothard Questionnaire in Carpal Tunnel Syndrome Patients at Adam Malik Hospital, Medan
No full textBackground:: Accurate diagnosis of Carpal Tunnel Syndrome (CTS) is crucial
for appropriate treatment to improve patients' quality of life. However, not all
healthcare facilities have nerve conduction testing equipment, and the cost of
testing is high, resulting in many cases going undiagnosed. Given these
limitations, a questionnaire or instrument has been developed to assist clinicians
in diagnosing CTS.
Objective: To determine the diagnostic accuracy of the Boston Carpal Tunnel
Syndrome Questionnaire (BCTSQ) compared to the Kamath and Stothard
Questionnaire (KSQ) at Adam Malik Hospital in Medan.
Metode Penelitian: This study used an observational analytical design on 51
patients (67 hands were examined) with CTS at Adam Malik Hospital in Medan
who met the research criteria and were confirmed by nerve conduction
examination. Statistical analysis was then performed to assess sensitivity,
specificity, positive predictive value, negative predictive value, positive likelihood
ratio, negative likelihood ratio, accuracy, and AUC and ROC values.
Results: There were 51 research subjects, with the majority being female (66.7%).
The diagnostic test results for KSTK-B showed a sensitivity of 83.6%, specificity
of 66.7%, PPV of 92.0%, NPV of 47.0%, LR+ of 2.5, LR- of 0.25, accuracy of
80.5%, and AUC of 0.752. Meanwhile, KKS had a sensitivity of 87.2%, specificity
of 75.0%, PPV of 94.1%, NPV of 56.2%, LR+ of 3.49, LR- of 0.17, accuracy of
85.1%, and AUC of 0.811.
Conclusion: In this study, the Kamath and Stothard Questionnaire had better
sensitivity, specificity, PPV, NPV, LR+, LR-, accuracy, AUC value, and ROC
compared to the Boston Carpal Tunnel Syndrome Questionnaire in diagnosing
Carpal Tunnel Syndrome.
Keywords: Boston Carpal Tunnel Syndrome Questionnaire, Kamath and Stothard
Questionnaire, Nerve Conduction Study, Carpal Tunnel Syndrome.145 PagesTesis Magiste