Portal Jurnal Politeknik Negeri Semarang
Not a member yet
3817 research outputs found
Sort by
Rekayasa Mesin Batik Tulis Berbasis CNC dengan Canting Elektrik
Get PDFBatik adalah salah satu kerajinan tradisional khas Indonesia yang telah mendunia. Seni membatik umumnya dilakukan di atas selembar kain dengan menggunakan lilin khusus. Cara membatik secara umum adalah memberi motif pada kain dengan memberi malam cair di titik-titik secara manual dan membutuhkan waktu yang lama. Tujuan penelitian ini adalah merancang dan membuat Mesin Batik Tulis Berbasis CNC Dengan Canting Elektrik yang berguna bagi UMKM serta menguji kesesuaian corak dan kecepatan proses produksi. Metode yang digunakan adalah observasi, perancangan, pembuatan, pengujian serta melakukan perbaikan sesuai hasil terbaik dari setiap perlakuan. Mesin Batik Tulis Berbasis CNC Dengan Canting Elektrik yang kami rancang memiliki kelebihan pada proses tulis batik yang lebih stabil, cepat dan bisa digunakan pada motif yang sama dan berulang-ulang. Mesin ini memiliki keunggulan dapat menggabungkan berbagai macam desain sesuai corak dan motif sedangkan proses tulis batik manual mebutuhkan waktu yang lama dan factor kelelahan tenaga kerja yang menjadi kendalanya. Hasil rancangan dan pembuatan Mesin Batik Tulis Berbasis CNC Dengan Canting Elektrik dengan sumber input daya 12 volt, motor stepper nema 17, Artsoft Mach3 sebagai microcontroller, sistem pergerak sumbu X dan Y menggunakan belt ”“ pulley sedangkan sumbu Z menggunakan leadscrew. Dimensi mesin 900 x 640 x 320 (mm), work area 600 x 450 x 30 (mm). Dapat dijalankan dengan PC/laptop melalui software Mach3 dan Vetric Aspire sebagai CAD/ CAM. Hasil pengujian performa yang dilakukan, mesin dapat bekerja dengan baik sesuai dengan program corak yang direncanakan
Visualization of Two-Phase Flow Regime in Vertical Pipe Airlift pump
No full textAn airlift pump can be used to move from one location to another. The pump lifts liquid or solid particles from air bubbles through a vertical pipe. In this experiment, the airlift pump system was modified using a microbubble generator installed on the injector to produce air bubbles. Two injectors were installed with a swirl model. This study aims to visualise the flow pattern that forms in a vertical pipe when air bubbles lift water toward the endpoint. The flow pattern was observed by varying airspeed and water column h in the vertical pipe. The method in this study was carried out using a two-phase flow (air-water). An acrylic pipe with an inner diameter of 50 mm and a height of 327 cm was used in this study. The immersion ratios were set to 0.44, 0.50, 0.56, 0.62, and 0.68. Air was injected into the system through a compressor injector, and air release was controlled by an airflow meter. m ³/h, 1.5 m ³/h, 2 m ³/hour, 2.5 m ³/h, and 3 m ³/h. The flow pattern in the thriller pipe is captured using a video camera. The research results show that bubble, slug, churn, and annular flow patterns are formed owing to variations in the airflow injected into the system. The slug flow changed to an annular flow as the slug flow speed increased. The slug and churn flows lifted the water, and the annular flow reversed the buoyancy force of the slug and churn flows. This study concludes that the ratio of the water column height in the vertical pipe affects the driving force for lifting water to the separator. The greater the immersion ratio, the better is the pump performance. In addition, the influence of the injected airflow forms a flow pattern that can move water from the bottom to a certain height
PENERAPAN TEKNOLOGI BIODIGESTER SKALA RUMAH TANGGA SEBAGAI SARANA PENDUKUNG PRODUKSI SUSU KAMBING DI KUNCEN FARM MIJEN
Get PDFBiogas is an environmentally friendly alternative energy source that is widely developed in society. Livestock waste is a source of biogas that is easy to obtain and the installation of digestion is easy, making biogas used by the community as an alternative to LPG. Kuncen Farm is a livestock farmer group that has a business cultivating dairy goats, fattening goats (Jawarandu Goats) and breeding Etawa goats. So far, goat manure waste is still managed conventionally, where only organic fertilizer is used for community agricultural needs and only makes up 30-50% of the total manure waste. Goat waste that is not used ends up being simply collected, producing an unpleasant odor and disturbing the environment. Based on the problems faced by Kuncen Farm and the potential of goat manure waste as a source of biogas, the application of biodigester technology on a household scale is a solution to goat manure waste as well as being a supporting facility for goat milk production at Kuncen Farm. This biodigester technology is made from PE plastic and utilizes used items around the house that can be used, such as used bottles, used stoves, motorbike tire rubber, etc. The main product in the form of biogas is used as fuel in gas stoves for goat's milk production and the by-product can be used as liquid fertilizer or organic compost which has economic value. This biogas stove can replace LPG fuel for cooking goat's milk. Furthermore, this biodigester technology can be installed on each group member
THE ROLE OF BUDGETARY PARTICIPATION, CLARITY OF BUDGET OBJECTIVES IN IMPROVING MANAGERIAL PERFORMANCE WITH LEADERSHIP STYLE AS MODERATION: AN EMPIRICAL STUDY IN UNIVERSITY X
Get PDFThis research aims to evaluate the relationship between budgetary participation, clarity of budget objectives, and leadership style on managerial performance at the University X. The approach used is quantitative descriptive, with the collection of primary data through the distribution of online questionnaires to 47 respondents selected using purposive sampling.The data analysis tool used is Moderated Regression Analysis. The research findings indicate that budgetary participation and clarity of budget objectives have a positive impact on managerial performance. However, leadership style only reinforces the relationship between budgetary participation and managerial performance, while not significantly influencing the relationship between the clarity of budget objectives and managerial performance.These findings provide important insights that budgetary participation and clarity of budget objectives can be determinants of managerial performance, with leadership style playing a reinforcing role in this relationship. The implications of this research can be used as a basis for management to enhance performance by improving budgetary participation and clarity of budget objectives, taking into account the role of leadership style in this contex
JOB INTERVIEW ANXIETY IN ENGINEERING STUDENTS: CAUSES AND MITIGATION STRATEGIES
Get PDF Penelitian ini menyelidiki prevalensi dan penyebab kecemasan praktek wawancara kerja mahasiswa teknik di Politeknik Negeri Semarang. Survei ini melibatkan 290 mahasiswa dan menggunakan kuesioner terstruktur yang mencakup informasi demografis, pengukuran tingkat kecemasan, kecemasan terkait wawancara kerja, efektivitas sesi latihan, penyebab dan strategi mengatasi kecemasan. Hasil penelitian menunjukkan tingkat kecemasan umum ada di tingkat sedang, namun kecemasan meningkat saat praktek wawancara kerja. Sesi latihan secara signifikan mengurangi tingkat kecemasan dan meningkatkan percaya diri mahasiswa. Penyebab utama kecemasan termasuk kurangnya pengalaman mengikuti wawancara kerja, tekanan untuk dapat memenuhi ekspektasi, dan ketakutan terhadap pertanyaan yang tidak mampu dijawab. Studi ini menyoroti perlunya program dukungan yang komprehensif dari institusi pendidikan untuk mempersiapkan mahasiswa dalam menghadapi wawancara kerja sehingga dapat mengurangi kecemasan dan meningkatkan kesiapan mahasiswa ketika memasuki dunia kerja. Abstract This study investigates the prevalence and causes of job interview anxiety among engineering students at the State Polytechnic of Semarang (Polines). The survey, which included 290 students, utilized a structured questionnaire that addressed demographic information, general anxiety levels, specific job interview anxieties, the effectiveness of practice sessions, causes of anxiety, and coping strategies. The results reveal moderate levels of general anxiety among the students, with heightened anxiety specifically related to job interview preparation and the waiting period before interviews. Practice sessions and mock interviews significantly reduced anxiety levels and improved student confidence. Key causes of anxiety included lack of job interview experience, pressure to meet expectation, and fear of unanswerable questions. The study also highlights the need for comprehensive support programs from educational institutions to better prepare students for job interviews. It can help alleviate job interview anxiety and enhance students”™ transition into the workforce
Efek Sandblasting Terhadap Karakterisasi Pelapisan Coating 95MXC Pada Stainless Steel 304 Menggunakan Metode TWAS (Twin Wire Arc Spray)
Get PDFImpeller adalah komponen utama pompa sentrifugal yang sering mengalami kegagalan seperti erosi, korosi dan kavitasi. Untuk mencegah kegagalan tersebut, salah satu cara yang digunakan adalah memberikan pelapis dengan metode TWAS. Pada penelitian yang telah ada, coating dengan metode TWAS menjadi salah satu pilihan yang banyak digunakan, namun belum banyak penelitian yang membahas mengenai pengaruh pengulangan sandblasting pada coating metode TWAS. Penelitian ini bertujuan untuk mengetahui pengaruh pengulangan sandblasting pada impeller pompa berbahan baku stainless steel 304 dengan metode Twin Wire Arc Spray Coating dengan NiAl sebagai bond coat dan FeCrBSiMn sebagai top coat. Penelitian ini menggunakan spesimen tanpa diberikan pelapisan dan spesimen tebaik yakni yang diberi pelapisan dengan satu pengulangan sandblasting. Karakterisasi dilakukan untuk mengetahui kekasaran permukaan (ISO 8503), kekerasan lapisan (ASTM E384), coating (ASTM D4541), dan laju korosi (ASTM G102). Pengujian SEM dan analisis ImageJ dilakukan untuk mengetahui struktur lapisan. Hasil penelitian menunjukan sandblasting dengan satu pengulangan memiliki hasil kekasaran permukaan dan ketebalan lapisan terendah. Namun, memiliki hasil karakterisasi lapisan paling optimal dengan porositas dan unmelt terendah, kekerasan tertinggi dengan 1081.6 HV dengan coating yang sudah sesuai dengan standar yakni 14.5 MPa dan semakin banyak pengulangan sandblasting, semakin tinggi laju korosinya. Kesimpulan dari penelitian ini adalah satu pengulangan sandblasting dalam metode TWAS sudah memberikan kualitas terbaik yang dapat meningkatkan performa dan penggunaan impeller pompa
EVALUASI KAPASITAS BENDUNG UNTUK PERENCANAAN CHECKDAM SEBAGAI PENGENDALIAN SEDIMENTASI DI BENDUNG LOGUNG
Get PDFSedimentation that occurs in the Logung Weir in Kudus Regency can reduce the capacity of irrigation services. The conturmeisure for sediment by build a check dam or normalization. The methods used in this analysis include hydrological analysis using the Hec-HMS application to obtain a 50 year planned flood discharge, erosion rate analysis using the Universal Soil Loss Equation (USLE) method and sediment analysis using the Sediment Delivery Ratio (SDR) method. Furthermore, comparing the efficiency between normalization work and making check dams and their maintenance. Analysis of the amount of sediment in the Logung Dam catchment is 1.18 mm/year with a sedimentation rate of 0.27%, which is 4750.87 m ³/year. The sediment storage capacity at Logung Weir is 1,918.00 m ³, it is necessary to increase the storage capacity of 2,832.61 m ³. For scenario 1, normalization/dredging is carried out 3 times a year, with an operational cost of IDR 707,425,977.00/year. Within a period of 50 years the total cost that must be incurred is Rp. 155,503,120,928.41. Scenario 2 is the construction of a check dam at the upstream of Logung Weir, the location is suggested at Sta. 11+50. The cost required Rp. 4,171,067,132.16 for construction and annual dredging costs of Rp. 235,808,659.01. Within a period of 50 years the total costs to be incurred amounted to 56,005,440,774.97. Comparison of the 2 scenarios shows that a more efficient long-term value is the construction of check dams and their operations
Design and Simulation of Asynchronous Buck Converter using Fuzzy Logic Controller (FLC)
Get PDFCurrently, Indonesia's energy is running out andhas received serious attention so the Government targets thatby 2050 the role of renewable energy will be at least 31%. Thisencourages the production of various alternative energysources that are environmentally friendly and available, suchas solar power plants. However, solar intensity and a dynamicenvironment strongly influence the output power generated bysolar panels. So in this research, an asynchronous buckconverter design using MPPT will be made to track themaximum power point of solar panels with the fuzzy logiccontroller method which will be applied to Monocrystallinesolar panels with a capacity of 300WP. Fuzzy MPPT will adjustthe duty cycle by PWM Arduino Nano on the asynchronousbuck converter to keep reaching the maximum power point.The results show that the developed system can increase powerconversion efficiency and maintain output voltage stabilityunder various operational conditions. The implementation ofFLC as MPPT on Asynchronous Buck Converter successfullyoptimizes the power absorbed from solar panels, thussupporting the reduction of electrical energy consumption fromPLN in the Jakarta Global University student associationsecretariat building. This implementation is expected to be areference for the implementation of a smarter and moresustainable energy management system in the future
Analysis Of Solar Power Plants With A Capacity Of 100 Wp With Automatic Transfer Switch In The Energy Conversion Laboratory Of Semarang State Polytechnic
Get PDFSolar energy is one of the renewable energy sourcesby utilizing the sun as its energy source. The planning of thePLTS uses an on-grid system, the system is still connected tothe PLN network. The system is used as a backup forelectricity flow. The system will work automatically when thePLN electricity flow is cut off by utilizing the AutomaticTransfer Switch (ATS) control system. The PLTS was tested bymeasuring the voltage, current, and input and output powerfor 5 days from 09.00-15.00 WIB with data collection every 60minutes. Then calculations were made to determine theefficiency of the PLTS. Calculations were also made of theenergy produced by the panels needed and produced by thelights ideally and actually. The results of the DC voltage andDC current tests on average at a load of 70 Watts produced bythe solar panel were 12.7 V and 2.41 A with a data collectionperiod of 7 hours, producing energy of 214.3 Wh andproducing the highest efficiency of 7.9% and the lowest 4.84%
The Impact Of Coal And Nickel Shocks On Stock Volatility Throughout The Dynamic Era
Get PDFNumerous scholars have examined the relationship between stock returns and metal commodities, but there has been less emphasis on specific metal commodities such as coal and nickel. This study sought to investigate the correlation between coal and nickel price fluctuations and their impact on stock market volatility. The researchers employed the GARCH and EGARCH models for analysis. This study utilized data on coal price, nickel price, and two stock market indices in Indonesia, specifically LQ45 and IDX30, spanning from January 2020 to December 2023. The results indicate that there was no substantial correlation between coal shock and nickel shock on stock market volatility. The EGARCH model would be more suitable for prediction. The significance of this research lies in its discovery of the relationship between coal shock and nickel shock on stock return throughout a dynamic period