Evaluasi Desain Termal Kondensor Pltn Tipe Pwr Menggunakan Program Shell and Tube Heat Exchanger Design

The study was executed to get a quick calculation method for the design of equipment heat exchanger type shell and tube with a program shell and tube heat exchanger design. The purpose of this study was to obtain the results of the validation program shell and tube heat exchanger design of a condenser with power 4368.75 kW and the results of the evaluation program shell and tube heat exchanger design on the thermal design condensers nuclear power plant AP1000 PWR type. Input data into the program is done by inserting the parameters temperature, flow rate, physical properties and geometrical dimensions of the available designs of heat exchanger equipment specifications. Parameter for comparison of data can be obtained from the results of other calculations or experimental data. The results of comparison of the validation program shell and tube heat exchanger with condenser design calculations showed the highest difference found on Utube parameter equal to 1.3% lower than the design condition. This occurs because of differences in calculation between the program designed. The result evaluation of program shell and tube heat exchanger design toward the thermal design condensers nuclear power plant PWR type AP1000 obtained unknown parameters from the technical specifications

Perancangan dan Analisis Aliran Udara Sistem Ducting Cloud Kitchen dengan Metode Computational Fluid Dynamics

Cloud Kitchen is a commercial kitchen that serves food for delivery or takeaway without dine-in customers. Because the cloud kitchen consists of many kitchens, good air circulation is needed. The total volume of the 15 kitchen units in the cloud kitchen is 249.8 m3, so to meet commercial kitchen standards that have a minimum Air Change per Hour (ACH) value of 30 ACH, an air change of 4410 m3/h with a ducting system is required. From the simulation results, the air velocity distribution in the ducting ranges from 0 m/s to 92.426 m/s, while the pressure distribution in the ducting ranges from -578.824 Pa to 11639.58 Pa, and the distribution of air temperature in the ducting ranges from 49.8°C to 65.167°C. The chosen exhaust fan is a CKE brand centrifugal fan with type CKE DGB-4.5#-NO and an exhaust capacity of 5712–10562 m3/h

Pengaruh Nozzle Dan Pengaruh Variasi Nozzle Terhadap Mini Turbine

Utilizing hydrokinetic energy through water turbines is a promising solution for generating renewable electricity. Water turbines play a crucial role in converting the kinetic energy of water into mechanical energy that can be used to drive electrical generators. This research focuses on the optimal design of a nozzle for water turbines to enhance the performance of hydrokinetic energy. The main objective of this study is to design and analyse an efficient nozzle for water turbines. The nozzle has a critical function in directing the flow of water efficiently and increasing the flow velocity into the water turbine. In the nozzle design, various parameters such as nozzle shape, diameter, angle, and length are considered to achieve optimal performance. The results of this research demonstrate that an optimal nozzle design can significantly enhance the performance of hydrokinetic energy in water turbines. An efficient nozzle design can increase the flow velocity, thereby resulting in increased power output from the turbine. Moreover, the use of genetic algorithms in optimizing the nozzle design aids in efficiently obtaining an optimal design

Analisis Aliran Udara dan Kenyamanan Termal di Laboratorium Perpindahan Panas dan Massa menggunakan Metode Computational Fluid Dynamics (CFD)

Air circulation and thermal comfort are some of many factors that affects user’s behavior in indoor activity, particularly in learning activity. With appropriate air quality and thermal comfort, it is easier for students to focus on the learning process. In addition, better air circulation can also benefit to the health of the people inside the building, for instance, according to WHO (World Health Organization), appropriate airflow may reduce the spread of SARS-CoV-2 which lately has caused a COVID-19 pandemic. However, air circulation and distribution have not a concern yet due to existing room condition and advanced technology that is needed, in L 609 classroom and Heat & Mass Transfer Laboratory, in this research. CFD method implementation for this case is used to show existing air circulation condition and necessary recommendations to get better air circulation. CFD simulation is done 3 dimensionally with 44344 nodes tetrahedral mesh on 2 configuration room condition, which are classified based on air input from AC, door gap, and with or without window opening. Based on CFD simulation results, the 2nd configuration with window opening indicate the best configuration with air velocity around 0,8 m/s dan room temperature 295,8 – 302,1 K. With window opening, the air flow condition met the ANSI/ASHRAE 55 and hoped to reduce COVID-19 spreading

Tailoring surface codes for highly biased noise

The surface code, with a simple modification, exhibits ultra-high error correction thresholds when the noise is biased towards dephasing. Here, we identify features of the surface code responsible for these ultra-high thresholds. We provide strong evidence that the threshold error rate of the surface code tracks the hashing bound exactly for all biases, and show how to exploit these features to achieve significant improvement in logical failure rate. First, we consider the infinite bias limit, meaning pure dephasing. We prove that the error threshold of the modified surface code for pure dephasing noise is $50\%$, i.e., that all qubits are fully dephased, and this threshold can be achieved by a polynomial time decoding algorithm. We demonstrate that the sub-threshold behavior of the code depends critically on the precise shape and boundary conditions of the code. That is, for rectangular surface codes with standard rough/smooth open boundaries, it is controlled by the parameter $g=\gcd(j,k)$, where $j$ and $k$ are dimensions of the surface code lattice. We demonstrate a significant improvement in logical failure rate with pure dephasing for co-prime codes that have $g=1$, and closely-related rotated codes, which have a modified boundary. The effect is dramatic: the same logical failure rate achievable with a square surface code and $n$ physical qubits can be obtained with a co-prime or rotated surface code using only $O(\sqrt{n})$ physical qubits. Finally, we use approximate maximum likelihood decoding to demonstrate that this improvement persists for a general Pauli noise biased towards dephasing. In particular, comparing with a square surface code, we observe a significant improvement in logical failure rate against biased noise using a rotated surface code with approximately half the number of physical qubits.Comment: 18+4 pages, 24 figures; v2 includes additional coauthor (ASD) and new results on the performance of surface codes in the finite-bias regime, obtained with beveled surface codes and an improved tensor network decoder; v3 published versio

Analisis Kinerja Coolant Pada Radiator

This research learn about characteristic of radiator coolant effectiveness, which are influenced by flow rate, density, and fluid viscosity. Experimental method is used to get parameters: such as coolant temperature, air temperature and flow rate. This study use ɛ-NTU method to analyze the data. The results of coolant A, B, and water have effectiveness of 40%, 37%, and 36% respectively, it is caused by coolant A have the biggest Universal coefficient number and convection coefficient number are compared with coolant B and water

STUDY PERBANDING BIAYA PEMESINAN PADA PROSES DRILLING MENGGUNAKAN PAHAT HSS DAN KARBIDA

Pada proses pembuatan suatu produk, terdapat  beberapa hal penting yang perlu diperhatikan, seperti perhitungan waktu pemesinan, umur pahat serta biaya produksi.  Waktu pemesinan memberi pengaruh terhadap perhitungan biaya pemesinan.Perbedaan parameter potong merupakan salah satu faktor yang dapat mempengaruhi waktu pemesinan serta tingkat kecepatan keausan mata pahat. Semakin mata pahat cepat mengalami keausan maka mata pahat tersebut akan mengalami penggantian sehingga biaya pada mata pahat akan semakin tinggi, dan juga mempengaruhi biaya produksi. Tujuan dari penelitian ini adalah untuk mengetahui perbanding biaya produksi pada proses drilling dengan menggunakan dua jenis mata pahat yaitu HSS dan Karbida. Penelitian dilakukan dengan melakukan variasi parameter pemotongan dan pengamatan keausan yang terjadi pada kedua mata pahat dan mengukur waktu pemotongan yang dicapai, kemudian melakukan perhitungan biaya produksi dengan menggunakan persamaan biaya permesinan.Dari hasil penelitian dapat dinyatakan bahwa perbedaan parameter pemotongan sangat mempengaruhi waktu pemesinan serta biaya produksi. Pada jenis pahat HSS 1 sampai HSS 3 waktu pemesinan yang didapat 114,17 menit dengan biaya produksi Rp. 844.900, 103,36 menit dengan biaya produksi Rp. 935.200, 95,87 menit dengan biaya produksi Rp. 1.033.900 dan pada jenis pahat karbida 1 sampai karbida 3 waktu pemesinan yang diperoleh 109,18 menit dengan biaya produksi Rp. 1.052.900, 93,33 menit dengan biaya produksi Rp. 1.105.000, 80,8 menit dengan biaya produksi Rp. 1.169.500

CFD Investigation of Flow Over a Backward-facing Step using an RNG k-? Turbulence Model

Backward-facing step (BFS) is a benchmarked geometry for visualizing recirculation flow and validating turbulence models. Nowadays, numerical analysis with the CFD method has became more popular and has stimulated research involving CFD without avoiding the experimental method. In this paper, flow over a BFS was numerically investigated with an RNG k-? turbulence model to predict recirculating flow. BFS geometry refers to the geometry proposed by Kasagi & Matsunaga; it is three-dimensional, with inlet Re = 5.540. The paper aims to investigate the performance of the RNG k-? turbulence model over a BFS. Two important parameters were analayzed: the performance of the RNG k-? on the recirculation zone and on the reattachment length. Recirculation flow is presented by the x-velocity for Y = 17.4 mm and Y = 34.9 mm. In these Y-section, the RNG k-? is compared to the STD k-? and both models show the recirculation flow occurred from X = 0 mm to about X = 200 mm. The following results were obtained. The RNG k-? predicted a slightly higher x-velocity component than that predicted by the STD k-?. This result shows that the RNG k-? turbulence model is suitable for predicting recirculation flow on the BFS. The reattachment length was measured by non-dimensional X/h to the x-velocity component with the RNG k-? turbulence model. The analyzed data were taken from X/h = 4.5 to X/h = 10, on the x-velocity component from Y = 17.4 mm. The reattachment point was achieved at X/h = 7.22, close to that achieved by Kasagi & Matsunaga of X/h = 6.51

Analisis Pengaruh Karakteristik , Leverage dan GCG Perusahaan Manufaktur Sektor Basic Industry dan Chemical serta Consumer Goods yang Listing di BEI Periode 20130-2016 terhadap Tax Avoidance

The objective of the research is to observe the effect of characteristic, leverage and corporate governance to tax avoidance in manufacturing company listed in BEI from 2013-2016. Population in this research consists of 109 companies. The test of hypothesis in this research uses regression linier analysis. The result of this research shows that capital intensity and ROA have significant effect to tax avoidance, while size, leverage, sales growth, corporate governance don’t have significant effect to tax avoidance

Rancang Bangun Mesin Penghancur Kaleng Minuman Berbasis Sistem Pneumatik

Kaleng bekas sangatlah sulit untuk dapat didaur ulang dan dapat mencemarkan lingkungan. Dengan adanya pembuatan rancang bangun mesin penghancur kaleng minuman ini maka dapat mempermudah untuk melakukan pemindahan kaleng bekas menuju tempat daur ulang. Rancang bangun mesin ini dibuat dengan membentuk tempat untuk piston silinder pneumatik beserta dengan tempat kaleng. Pembentukan tersebut membutuhkan pelat L dan dihubungkan dengan menggunakan baut maupun dengan pengelasan. Hasil dari rancang bangun ini selain membentuk mesin penghancur kaleng minuman juga dilakukan pengujian ketahanan kerangka terhadap beban untuk menahan silinder pneumatik ketika sedang bekerja menggunakan simulasi untuk tegangan, perpindahan dan regangan untuk memastikan keamanan dari sisten yang dirancang. Simulasi membuktikan bahwa alat penghancur kaleng yang dirancang tetap dalam batas aman meskipun tekanan dari kompressor mencabai 0.8 Mpa