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The Characterization Methods of Natural Fibers (Cellulose Fibers) as Reinforcement for Polymer Matrix Composites: A Review : Natural Fibers Characterization
No full textThe interest in using natural fibers as reinforcement in polymer matrix composites is increasing, driven by their abundant availability, biodegradability, and significantly lower production costs compared to synthetic fibers. The cellulose content in natural fibers has a significant impact on the mechanical properties and thermal stability of the fibers, ultimately affecting the mechanical strength of the composites. To enhance the cellulose content in the fibers, one approach is to use alkali treatment with a NaOH solution on the fibers. To evaluate the effectiveness of the chemical treatment and study the physical and mechanical characteristics of the fibers, as well as to assess the potential and feasibility of the fibers as reinforcement in polymer matrix composites, a series of characterizations or tests on the fibers needs to be conducted. This review article will discuss in depth the methods of characterizing natural fibers and the influence of their physical and mechanical properties on composite strength. This article is expected to provide a positive contribution to the development of polymer matrix composite materials reinforced with natural fibers
STABILISASI TANAH LEMPUNG LUNAK MENGGUNAKAN KALSIT DAN RCC 15 DALAM PENINGKATAN NILAI CBR UNSOAKED
Full text linkSoft clay soil, which is often found in coastal and lowland areas of Indonesia, has characteristics such as low bearing capacity, high plasticity, and easy to subside under load, making it a challenge in infrastructure projects. Various soil stabilization methods have been developed, one of which is the use of chemical stabilizers. This study examines the use of Calcite (CaCO3) and Spent Catalyst RCC 15 as stabilization materials to improve the quality of soft clay soil. Calcite is known to reduce plasticity and increase soil bearing capacity, while Spent Catalyst RCC 15, as industrial waste, has the potential to improve soil structure and increase soil stability. Tests were conducted in the laboratory by mixing 6% Calcite and variations of Spent Catalyst RCC 15 (0%, 4%, and 8%) in soil samples from Cililin, West Java. The test results showed that the combination of Calcite and Spent Catalyst RCC 15 significantly increased the California Bearing Ratio (CBR) value of the soil, which means increasing the soil bearing capacity. The higher the percentage of Spent Catalyst RCC 15, the higher the CBR value obtained, indicating the effectiveness of this combination of stabilization materials in improving soft clay soil. These findings indicate the potential for an economical and sustainable solution to address soft clay soil problems in Indonesia and support more environmentally friendly industrial waste management
EVALUASI EFEKTIVITAS BAKTERI BACILLUS MEGATERIUM SEBAGAI MATERIAL INJEKSI SELFHEALING UNTUK PERBAIKAN RETAK BETON
Full text linkConcrete deterioration is a significant problem in the construction industry, which can reduce the service life and structural performance of buildings. Conventional repair methods, such as the use of epoxy and other bonding materials, are commonly used to improve the durability of concrete, but often rely on synthetic materials that are not environmentally friendly. This study focuses on the use of Bacillus megaterium bacteria combined with epoxy as a self-healing injection material, offering an environmentally friendly and sustainable solution to overcome concrete cracking. This study explores the potential of Bacillus megaterium to biologically repair concrete structures by adding the bacteria to epoxy at concentrations of 5%, 10%, 15%, 20%, and 25%. Concrete blocks measuring 100 mm x 100 mm x 500 mm were tested using flexural strength, ultrasonic wave velocity (UPV), and scanning electron microscopy (SEM) tests to assess the effectiveness of the repair. The results showed that at a concentration of 15%, Bacillus megaterium increased the flexural strength by 12.19% of the initial strength and the UPV velocity reached 3.19 km/s, which was almost equivalent to normal concrete. SEM analysis showed the formation of calcium carbonate deposits on the cracks, indicating the success of the self-healing process. This study shows that the application of Bacillus megaterium in epoxy provides an environmentally friendly alternative to conventional concrete repair methods, reduces dependence on synthetic chemicals, and extends the service life of concrete infrastructure. This innovation contributes to the development of more sustainable and efficient construction practices in civil engineering
Challenges and Solutions in Hydropower: Analyzing Francis Turbine Performance and Operational Dynamics
Full text linkThis paper addresses the global challenge of sustainable energy, exploring alternatives to dwindling fossil fuels and rising CO2. While renewables like solar and wind offer potential, they face geographical and intermittent limitations. Thermal and nuclear energies are discouraged due to severe environmental and health impacts. Hydropower emerges as a highly reliable and favored global solution, harnessing energy from flowing water, tides, and dams. It's the most prevalent renewable source for electricity, offering consistent, dependable, and emission-free supply. The Francis turbine is crucial to hydropower, known for its high efficiency. Its spiral casing, runner, and guide vanes efficiently convert water's energy into electricity. Water flows from a reservoir to the turbine, where guide vanes regulate entry to the runner, driving a generator. Our analysis reveals key factors affecting hydropower performance: energy source, guide vane opening, servomotor performance, and governor control system. Sediment accumulation at the inlet causes head loss, reducing optimal output. Misaligned guide vane openings can drop rotational speed, leading to suboptimal load. Servomotor issues like wear also require maintenance. A 5% speed drop setting effectively manages water pressure and flow, enabling smooth load escalation
ANALISIS KARAKTERISTIK PARKIR DI RUMAH SAKIT PANTI RAHAYU βYAKKUMβ PURWODADI GROBOGAN: ANALISIS KARAKTERISTIK PARKIR DI RUMAH SAKIT PANTI RAHAYU βYAKKUMβ PURWODADI GROBOGAN
No full textPanti Rahayu βYakkumβ Hospital Purwodadi has provided three parking spaces that are still within the hospital complex. In the parking area, it is currently unknown what the characteristics of parking and how much parking space is needed. This study aims to determine the characteristics of parking, capacity, and the need for existing parking spaces. The research method used is the observation method and literature study. This study was conducted for 3 days, namely Saturday, Sunday, and Monday, starting at 08.00 β 20.00 (12 hours) with a recorded time interval of 15 minutes. The results obtained were 602 vehicles for the highest parking volume for motorcycles and 156 vehicles for cars, the highest parking accumulation for motorcycles was 469 vehicles and 120 vehicles for cars, the parking index for cars was 122.45%, while for motorcycles it was 87.99%, the average duration of parking for motorcycles and passenger cars was 2.5 hours/vehicle and for parking turnover it had the same parking turnover rate between motorcycles and cars, The parking capacity for motorcycles is 1 vehicle, while for cars it is 3 vehicles. The total capacity for motorcycles is 533 SRP, while the capacity for cars is 49 SRP. However, when viewed from the highest incoming vehicle volume, the parking capacity is insufficient to meet the parking needs of patients, visitors and hospital employees. Researchers recommend that Panti Rahayu βYakkumβ Hospital Purwodadi add parking space or build a multi-story building parking lot
Influence of Service Quality on Customer Satisfaction at the Intan Grosir Passo Store Ambon
Full text linkThis study aims to analyze the influence of service quality on customer satisfaction at the Intan Grosir Passo Store. The underlying phenomenon is the persistent problems in the service dimension, such as late delivery of goods, slow responses to customer complaints, lack of employee knowledge regarding products, and untidy merchandise display. These conditions impact the storeβs sales fluctuations and potentially lower customer satisfaction levels. Therefore, this study focused on consumers who have shopped at the Intan Grosir Passo Store with the aim of determining the extent of the influence of service quality on customer satisfaction.Β The results of the regression test show the equation Y = 0.470X + e, with a coefficient of determination (RΒ²) of 0.589, which means that 58.9% of the variation in customer satisfaction can be explained by service quality, while the remaining 41.1% is influenced by other factors outside this study. The t-test produces a t-count value of 7.375> t-table 2.024 with a significance of 0.000 <0.05, so the hypothesis is accepted. Thus, service quality is proven to have a positive and significant effect on customer satisfaction at the Intan Grosir Passo Store
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Penelitian ini bertujuan untuk menganalisis pengaruh kualitas pelayanan terhadap kepuasan pelanggan pada Toko Intan Grosir Passo. Fenomena yang menjadi latar belakang adalah masih ditemukannya permasalahan dalam dimensi pelayanan seperti keterlambatan pengantaran barang, respon yang lambat terhadap keluhan pelanggan, kurangnya pengetahuan karyawan terkait produk, hingga penataan barang yang kurang rapi. Kondisi ini berdampak pada fluktuasi penjualan toko serta berpotensi menurunkan tingkat kepuasan pelanggan. Oleh karena itu, penelitian ini difokuskan pada konsumen yang pernah berbelanja di Toko Intan Grosir Passo dengan tujuan untuk mengetahui seberapa besar pengaruh kualitas pelayanan terhadap kepuasan pelanggan. Β Hasil uji regresi menunjukkan persamaan Y = 0,470X + e, dengan nilai koefisien determinasi (RΒ²) sebesar 0,589 yang berarti 58,9% variasi kepuasan pelanggan dapat dijelaskan oleh kualitas pelayanan, sedangkan sisanya 41,1% dipengaruhi oleh faktor lain di luar penelitian ini. Uji t menghasilkan nilai t-hitung 7,375 > t-tabel 2,024 dengan signifikansi 0,000 < 0,05, sehingga hipotesis diterima. Dengan demikian, kualitas pelayanan terbukti berpengaruh positif dan signifikan terhadap kepuasan pelanggan pada Toko Intan Grosir Passo
Determinants of Environmental Quality Index (EQI) in Indonesia in 2018-2022
Full text linkThe environment is a critical issue in sustainable development in Indonesia, with significant variations in environmental quality between regions. This study seeks to examine the influence of the Regional Government Budget, COVID-19 (as a dummy variable), Gross Regional Domestic Product (GRDP), and the Human Development Index (HDI) on the Environmental Quality Index (EQI) in Indonesia. The data for this study were obtained from BPSβStatistics Indonesia and the Ministry of Environment and Forestry, covering the period from 2018 to 2022. The analysis employs multiple linear regression using panel data. Panel model testing indicates that the fixed effects model with cross-sectional lag provides the best fit. The results show that, collectively, all variables have a significant influence on Indonesia's Environmental Quality Index (EQI). Individually, the Regional Government Budget for environmental purposes, the COVID-19 dummy variable, and the Human Development Index (HDI) have a significant positive impact on EQI. In contrast, Gross Regional Domestic Product (GRDP) has a significant negative effect. These findings highlight the need for comprehensive macro-socioeconomic policies to sustain and enhance environmental quality in Indonesia
Design of an Electrical Power Monitoring and Alert System Based on Internet of Things (IoT) for Chicken Coops
Full text link- The reliability of the electricity supply is a vital factor in ensuring the sustainability of modern poultry farming systems.Power outages or electrical disturbances can disrupt ventilation, heating, and lighting systems, resulting in decreased productivityon poultry farms. This study aims to design an Internet of Things (IoT)-based power supply detection and early warning system tomonitor electrical conditions in real-time and provide automatic notifications to farmers. The system was developed using aZMPT101B voltage sensor, an ACS712 current sensor, and a NodeMCU ESP8266 microcontroller, all of which are connected tothe Blynk platform for notification delivery. The research employed a prototyping approach, consisting of five stages: communication, planning, design, construction, and implementation. Testing was conducted in a closed poultry house located inWonolopo, Mijen, Semarang City. The results showed that the system was able to detect power disturbances with an accuracy rateof 97.6% and a notification response time of less than 3 seconds. The system proved effective in providing early warnings to farmers and enhancing the operational safety of electricity-based poultry farms
PENGARUH TOTAL HUTANG PERUSAHAAN, NILAI PENERBITAN DAN PERINGKAT PENERBITAN SUKUK TERHADAP RETURN SAHAM
Full text linkPenelitian ini bertujuan untuk menganalisis pengaruh penerbitan sukuk terhadap return saham perusahaan di Indonesia, dengan variabel independen berupa total hutang perusahaan, nilai dan rating penerbitan. Perusahaan menerbitkan sukuk sebagai alternatif pembiayaan yang diharapkan dapat meningkatkan kinerja dan aktivitas perusahaan, sehingga investor akan tertarik untuk melakukan investasi. Penelitian ini menggunakan metode deskriptif kuantitatif, dengan data sekunder berjumlah 49 sampel. Regresi linier berganda digunakan untuk menguji return saham atas penerbitan sukuk. Hasil penelitian menunjukkan bahwa total hutang perusahaan berpengaruh negatif signifikan terhadap return saham perusahaan, nilai penerbitan sukuk tidak berpengaruh positif tidak signifikan terhadap return saham perusahaan, peringkat sukuk berpengaruh positif signifikan terhadap return saham perusahaan, semua variabel independen secara bersama memiliki pengaruh signifikan terhadap variabel dependen
Analisis Sistem Pembangkit Listrik Tenaga Surya Untuk Pompa Air di Kelurahan Terong Dlingo Bantul dalam Kegiatan Pemberdayaan Masyarakat Oleh Mahasiswa
Full text linkNaskah ini memaparkan analisis sistem Pembangkit Listrik Tenaga Surya untuk Pengelola Air Bersih/PAB di Kalurahan Terong Dlingo Bantul sebagai mitra produktif yang berperan penting dalam mendistribusikan air bersih untuk kebutuhan rumah tangga. Air yang dikelola memiliki sumber dengan lokasi di bawah jalan raya dengan elevasi tinggi 40 m. Air dinaikkan menggunakan pompa submersibel 2 HP kapasitas 10 m3/jam, untuk dapat didistribusikan kepada masyarakat. Selama ini pompa menggunakan tenaga listrik dari PLN, dikarenakan daya yang besar maka biaya listrik juga besar. Untuk mengurangi biaya membeli listrik, maka dibangun PLTS untuk mengurangi ketergantungan biaya listrik yang besar. Untuk itu dilakukan analisis kebutuhan komponen utama yang diperlukan membangun PLTS sesuai dengan beban daya pompa tersebut. Hasil analisis dapat ditentukan kebutuhan komponen PLTS antara lain panel surya 600 Wp sejumlah 4 buah, Solar charge controller/SCC dengan beban arus lebih besar atau sama dengan 80 A, Baterai dengan tegangan 12 V kapasitas 200 Ah berjumlah 4 buah dan Inverter dengan tegangan inout 24V DC daya nominal 5.000 VA dan beban arus listrik minimal 70A. Dengan adanya PLTS ini diharapkan masyarakat Kalurahan Terong dapat menikmati kebutuhan air bersih dengan biaya yang lebih ringan