PENGARUH VARIASI KAPASITAS PEMANAS TERHADAP KONDISI SUHU DAN KELEMBABAN SERTA DURASI PEMANASAN PADA SCREENHOUSE BERBASIS EVAPORATIVE COOLING SYSTEM

The unpredictable weather changes in Indonesia cause various problems for the agricultural sector. One of which is the decline in productivity of farmers' crops up to 40% which is caused by non-optimal environmental conditions during the plant growth process. To be able to adapt to these conditions, it is necessary to have an optimal system of environmental conditioning for plant growth. In this research, a screenhouse temperature and humidity conditioning system was designed for the growth of tomato plants as a horticultural commodity with high potential and high economic value in Indonesia. The system design is modeled and tested through simulation on Vensim software by varying the furnace capacity by 4oC/hour, 6oC/hour, and 10oC/hour in order to see its effect on the internal screenhouse temperature and heating duration. Based on the simulation results of system design, the heating rate and duration for each furnace capacity variation are 4.74oC/hour (135 minutes per cycle), 6.9oC/hour (75 minutes per cycle), and 11.76oC/hour (45 minutes per cycle). The furnace capacity value of 10oC/hour is considered to be optimal and more energy efficient because it only requires a heating process for 180 minutes per day to maintain the screenhouse internal temperature in optimal temperature range for tomato plant growth, which is 18 - 24 oC with an offside value of ±0.5 oC. The stable cooling rate value for this system is in the range of 1 – 1.8oC/hour

RANCANG BANGUN ANTENA MONOPOLE MIKROSTRIP MENGGUNAKAN DEFECTED GROUND STRUCTURE BENTUK PERSEGI UNTUK OPTIMASI BANDWIDTH PADA APLIKASI KOMUNIKASI ULTRA-WIDEBAND

The development of UWB technology is very helpful in supporting high-speed data access. UWB offers a solution for large capacity for wide bandwidth. The frequency range for UWB systems between 3.1–10.6GHz will cause interference to wireless communication systems via wireless local area networks (WLANs) for IEEE 802.11a operating at 5.15–5.35GHz and 5.725–5.825GHz. This research aims to obtain a design of a rectangular printed monopole patch microstrip antenna and a slit using the Defected Ground Structure (DGS) technique to obtain bandwidth optimization on the UWB spectrum. For the implementation of the antenna design, the simulation method is used with the support of the RT/ Duroid substrate material. Realization of the design with the results of a manufactured antenna prototype with a minimalist size. The simulation and measurement results of the Absolute UWB bandwidth parameter at return loss < -10 dB (VSWR <2) the measurement value is 600MHz narrower than the simulation and for fractional bandwidth the measurement value is narrower by 0.21%. Resonance at the 5.2GHz frequency produces polarization with a gain value of 3.29dBi, omnidirectional and vertical polarization. As a prototype antenna to support the application of indoor wireless access communication devices that are low profile, compact with minimalist dimensions

KAJI EKSPERIMENTAL RETROFIT R404A DENGAN REFRIGERAN RAMAH LINGKUNGAN R290 PADA FREEZER

R404A refrigerant is still widely used as the working fluid in freezers with temperatures below -30°C. However, because of R404A’s high global warming potential (GWP) value, its use as a working fluid should be stopped immediately. One alternative is an environmentally friendly refrigerant, that is R290. In this study, the R404A refrigerant was replaced by R290 in a freezer that can reach -40°C. In the case of replacing a refrigerant with a different type, the reference used is the same charging volume in the system. The filling mass of R290 is the ratio of the density of R404A to R290 at its evaporation temperature, which is -40°C. The amount of R404A’s mass filling is 170 g, while the amount of R290’s mass filling is 62.9 g. Based on a 120-minutes testing, replacing R404A with R290 has resulted in the reduction of power input by 6.0%, as well as in the slight increase of its cooling capacity, which is 2.42%. As a result of the input power decrease and the cooling capacity increase, the COP in the freezer also increased, namely by 8.05%. More importantly, if a leak occurs in the refrigerant, the replacement of R404A with R290 can help reduce gas emissions that contribute to global warming. It is because the GWP value of R404A refrigerant, which is 3922, is replaced by the GWP value of R290 refrigerant, which is only 3

PERBAIKAN KEKERASAN DAN STRUKTUR MIKRO LOGAM KUNINGAN SEBAGAI BAHAN PROPELLER DENGAN METODE SHOT PEENING

Brass metal is widely used as a supporting equipment material, one of which is a propeller. The propeller itself is one component of the boat that rotates and produces thrust energy. The continuous use of propellers results in degradation or a decrease in quality and service life. The degradation of the propeller is affected by the hardness, toughness, and corrosion resistance of the working environment. To improve the quality of the propeller, shot peening treatment was carried out on its surface. Shot peening is a continuous shooting process with fine particles in the form of steel balls on the surface of the object. Shot peening can increase the density of the microstructure and produce compressive residual stress which causes the surface hardness to also increase. Shot peening is carried out with variations in duration of 2, 4, 6, 8, and 10 minutes, 100 mm shooting range, and 7 Bar firing pressure. The steel ball particles used have a hardness of 40-50 HRC and a diameter of 5 mm. The results of the hardness test showed an increase in the surface hardness of the spesimens for a duration of 2, 4, 6, 8, and 10 minutes, respectively 189, 294, 302, 324, 330, dan 341 HV. The microstructure of the spesimen after shot peening looks tighter and denser. The highest hardness value is 341 HV or an increase of 80% compared to raw material

Daftar Isi Volume 9 Nomor 1 Tahun 2023

Daftar Isi Volume 9 Nomor 1 Tahun 202

ANALISIS PENGARUH VARIASI TEKANAN GAS DAN PERSENTASE KETEBALAN LAPISAN BOUNDING DAN COATING PADA PROSES REBUILD-UP MATERIAL BAJA AISI 1045 DENGAN METODE ARC SPRAY TERHADAP TINGKAT KEREKATAN ANTAR LAPISAN

Each engine component has the durability that can decrease and wear due to continuous friction. The thermal spray method is an alternative that is used. The type of thermal spray that is found in the industry is Arc Spray. However, the peeling of the coating metal with the substrate is one of the problems. In this study, the variables that have contributed to the peeling of the coating layer were taken. The variables compared are the total thickness of the bounding and coating layers of 1 mm with a percentage of 50% : 50% and 30% : 70%. Another variation is gas pressure of 2 Bar, 3 Bar and 4 Bar in rebuild-up process of AISI 1045. Specimens with thickness percentage of 30% : 70% have significant difference in tensile strength value compared to the thickness percentage of 50% : 50% with an average difference of 5.02 MPa; 4.8975 MPa and 3.29 MPa in specimens with a gas pressure of 2 bar; 3 bars; 4 bars. The influences of thickness of bound and top coat have percentage effect 21.12% on each layer. As the gas pressure increases, the bonding value is higher because the higher gas, the smaller porosity which is proved by microstructural tests

DATA LOGGER DEBIT AIR DENGAN PROTOKOL M-BUS UNTUK APLIKASI CHILLER

The M-bus protocol is one of the communication protocols in the rapidly developing field of measurement. The protocol uses a pair of cables and can communicate with several measurement devices in two directions such as a flowmeter. In the chiller system, water circulation varies depending on the cooling load and set point of operation, consumption (electric power) and chiller efficiency, one of which can be calculated based on logging the flow of water that circulates over time, therefore the water discharge data logger becomes very important. This study aims to examine the water discharge data logger with the M-Bus protocol for chiller applications. The testing device includes a series of bench water meters as flowmeters (which water can be simulated circulated) equipped with an M-Bus pick-up sensor, M-Bus concentrator and logger, and software connected to a computer. Tests carried out with variations in water discharge based on the valve opening as a simulation of cooling load variations and see the results of recording from time to time on a computer. The display can be in the form of tables and graphs

PERANCANGAN 3D PRINTING CARTESIAN BERBASIS FUSED DEPOSITION MODELLING DENGAN UKURAN 200 X 200 X 200 mm

The technology  of adding manufacturing or 3D printing is one of the main issues in the concept of technology 4.0. The construction design of the 3D printing machine and the deflection of its construction significantly affect the accuracy of the dimension and shape the printed product. The study aims to obtain a construction design of a cartesian type 3 D printing machine based on fused deformation modelling, and to verify the maximum value of the deflection of the machine axis. The study method used VDI222, calculation analysis, and Finite Element Analysis (FEA) simulation using CAE Solidworks software to verify the strength and deflection of the machine design construction. The study results show the construction design of 3D printing machine has been obtained according to the requirement. The verified maximum deflection value is 0.036 mm, hence the maximum error in the dimensions and shape of the printed product for each layer will still be within the standard tolerance. In addition, its maximum deflection value is verified within the radial clearance value of each determined machine axis bearing

ANALISIS POTENSI SUMBER ENERGI ANGIN DI DESA SIMAN KABUPATEN LAMONGAN: ESTIMASI MENGGUNAKAN PEMODELAN SISTEM TURBIN ANGIN

Wind energy that can be utilized into electrical energy certainly requires sufficient wind speed so that the wind turbine can rotate and produce mechanical movement in the form of rotational torque which can then be converted into electrical energy. Before the application of the technology is carried out, this study is needed to examine the potential of wind energy produced in Siman Village, Lamongan Regency. To produce a power profile from wind energy sources, wind speed measurements are first carried out, followed by mechanical modeling and wind turbine electrical modeling. The maximum electric power generated from the simulation of electrical energy conversion using a wind turbine is 11.94 Watt with a maximum wind speed of 3.5 m/s. If converted in energy units, then in a day the wind energy that can be extracted into electrical energy is 286.56 Watt.h. When compared with the daily electrical energy needs in the household sector (9364 watt.h) the electrical energy generated through modeling is able to meet 3.1% of electricity needs in a day

SISTEM AKUISISI DATA TINGGI GELOMBANG LAUT BERBASIS IOT

Ocean wave height data is very much needed in the maritime world to support fishing activities, transportation, and coastal life. Ocean wave heights are easy to change so it is difficult to obtain measurement data, we need a system that is able to observe the behavior and changes in ocean wave height that is accurate and easy to monitor. The aim of this research is to design a data acquisition system for ocean wave height that is able to work with real time conditions and able be monitored at any time. The methods of this research is quantitative research using an experimental design. The system design consisted of field observations and literature studies, procurement of tools and materials, tool design, tool testing, and research data collection. Data collection techniques are carried out by testing sensors and displays on the application. The results showed that the Sea Wave Height Data Acquisition System that has been designed can work with an error percentage of 1.26% and has a very high level of measurement accuracy with an accuracy percentage of 98.74%. The results of the performance test of the Sea Wave Height Data Acquisition System that has been designed to be able to detect, collect, send, process, and display ocean wave height result data in real time