Autor: Akhyar - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Hot Tearing, Parameters, and Mould Types for Observation – Review
Autorzy:: Akhyar
Tematy:: casting defects
pouring temperature
mould temperature
mould types
wady odlewnicze
temperatura wylewu
temperatura formy
typ form; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/2127511.pdf Link otwiera się w nowym oknie
Opis:: Hot tearing is a casting defect responsible for external and internal cracks on casting products. This irregular undesired formation is often observed during solidification and freezing. The solidification of molten metal also causes thermal contraction and shrinkage, indicating the occurrence of hot tearing when the alloy is restrained by the mould design. The parameters affecting this process include the pouring and mould temperatures, the chemical composition of the alloy, and the mould shape. Also, the factors affecting hot tearing susceptibility include pouring and mould temperatures, the grain refiner, as well as pouring speed. There are many methods of measuring the level of susceptibility to hot tearing, one of which is the thermal contraction evaluation during metal solidification, observed in cast products through several mould types. This paper discusses the hot tearing overview, the effect of pouring temperature, mould temperature, grain refiner, pouring speed on hot tearing, the type of mould, and criterion for hot tear observation.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Evaluation of the roundness quality of galvanized steel plate due to variations in cutting speed and nozzle diameter during the laser cutting
Autorzy:: Aulia, U.
Akhyar, Akhyar
Tematy:: roundness quality
cutting speed
nozzle diameter
galvanized steel plate
laser cutting
prędkość skrawania
stal ocynkowana
blacha stalowa ocynkowana
cięcie laserowe; Pokaż więcej
Wydawca:: Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Powiązania:: https://bibliotekanauki.pl/articles/59122398.pdf Link otwiera się w nowym oknie
Opis:: Purpose: Generally, laser cutting processes aim to cut materials with high accuracy, as well as precise and near-perfect sizes and results. The purpose of this study is to evaluate the roundness quality of the holes cut by laser cutting on galvanised steel plates; two variations are given, such as cutting speed and nozzle diameter. Design/methodology/approach: The type of laser used is a fibre laser. The material used is galvanized steel with a thickness of 3 mm with dimensions of 200 mm in length and 200 mm in width. A round profile is good if the distance between the points of the geometric shape is the same distance from the centre point. Findings: The measurement results show that the smallest radius deviation is with an average value of 20.08 mm at a nozzle diameter of 2.5 mm and a cutting speed of 3 m/min, close to the initial radius value of 20.00 mm. Research limitations/implications: During the laser cutting process, The best roundness quality is the combination of a nozzle diameter of 2.5 mm and a cutting speed of 3 m/min with a small deviation (the index deviation is 0.4%). At the same time, the biggest deviation in this experiment is the combination of parameters with a nozzle diameter of 3 mm and a cutting speed of 4 m/min (the maximum deviation value is 1%). Practical implications: The use of the proposed nozzle diameter and cutting speed approach is an important requirement for industrial applications with laser cutting to get the right product for its intended use. Originality/value: This article presents different nozzle diameters and cutting speeds to reveal the roundness quality due to these variations, where the roundness quality will be adapted for a particular application.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Impact of pouring temperature on the mechanical properties of Al5.9Cu1.9Mg alloy
Autorzy:: Akhyar, Akhyar
Iswanto, P.T.
Malau, V.
Tematy:: mechanical properties
Al-Cu-Mg alloy
casting metal
pouring temperature
właściwości mechaniczne
Stop Al-Cu-Mg
metal odlewniczy
temperatura odlewania; Pokaż więcej
Wydawca:: Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Powiązania:: https://bibliotekanauki.pl/articles/2201133.pdf Link otwiera się w nowym oknie
Opis:: Purpose: This experiment aims to determine the influence of pouring temperature on the hardness, impact energy, tensile strength, and changes in the microstructure of the Al-5.9Cu- 1.9Mg alloy. Design/methodology/approach: A total of three samples of aluminium alloy were heated to 688, 738, and 788°C, and poured into permanent moulds in form of plates at a constant temperature of 220°C. The cast products are machined according to testing standards for hardness, impact tests, and tensile strength. Findings: The results showed that the metal hardness and impact energy increased to 103 BHN and 7.48 J at 788°C, respectively, while the tensile strength rises as the temperatures decreases. Furthermore, the changes in the microstructure were affected, which indicated that all the properties of the aluminium alloy were influenced by the variations in temperature. Research limitations/implications: During the metal casting process, only three different pouring temperatures affected the properties of the metal alloy, therefore, there is a need for more variations. Practical implications: The proposed pouring temperature parameter is an important condition for industrial foundry applications to obtain the right product for use in a machining element. Originality/value: This research shows the influence of the difference in pouring temperatures on the properties of metal alloys due to casting, where they will be adapted for a particular use.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Oceanographic Factors as the Indicators for Shipyard Industry Development in Kutaraja Fishing Port: A Preliminary Study
Autorzy:: Rizwan, Thaib
Jalil, Zulkarnain
Akhyar, -
Husaini, -
Tematy:: shipyard
fishing port
Kutaraja Ocean
oceanography
sediment; Pokaż więcej
Wydawca:: Polskie Towarzystwo Inżynierii Ekologicznej
Powiązania:: https://bibliotekanauki.pl/articles/1955542.pdf Link otwiera się w nowym oknie
Opis:: Shipyard development in Kutaraja Fishing Port is important to improve the port performance. The studies related to shipyards are mainly focused on their productivity, facility layout, production capacity, and management and planning. Meanwhile, there are still limited studies related to the influence of oceanographic factors on shipyard development. This research aimed to identify the impact of oceanographic factors on shipyard industry development in Kutaraja fishing port. The research was conducted from December 2020 to March 2021. The data analyzed in this study were tide, wind, current, wave, bathymetry, and sediment composition. The tide, wind, current, and wave data were collected for the last three years from Meteorology, Climatology, and Geophysical Agency. The current moves from two directions, from northeast and northwest, towards the coastal areas around the eastern part of Kutaraja fishing port, closed to the breakwater. The current in the eastern part moves faster than in the western part, and the western part of the sampling area mostly has shallow waters. The highest tide occurs at 12:00 with a water height of -0.3855 meters, and the lowest tide was at 19:00 with a water height of -1.0485 meters. Fine sand dominated the sediment in the sampling area. The result indicates that oceanographic factors are essential to be incorporated as one of the indicators for shipyard development.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Modification of Constrained Rod Casting Mold for New Hot Tearing Measurement
Autorzy:: Malau, V.
Akhyar, H.
Iswanto, P. T.
Tematy:: hot tearing
CRCM-Horizontal
HTS formula
casting; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/355427.pdf Link otwiera się w nowym oknie
Opis:: Hot tearing severity was evaluated in this experiment by introducing a new apparatus called Constrained Rod Casting Modified Horizontal (CRCM-Horizontal). Six constraint bars with different lengths can produce hot tearing on the cast sample. Mold position was modified from vertical to horizontal and the shape was changed from a harp shape to a star shape, which allows for the liquid metal to feed into each rod cavity simultaneously. Hot tearing development was recorded along the bars by a digital camera. A new Hot Tearing Susceptibility ( HTS) formula was developed for quantitative investigation of hot tearing on a cast sample. The parameters of the HTS formula are bar length of cast sample (Li), tear severity (Ci) and location of hot tear (Pi). Footprint charts and hot tear scales are used to illustrate hot tearing severity. The experiment was conducted with Al-1.36Zn-1.19Si and Al-5.9Cu-1.9Mg alloys to investigate the sensibility of the apparatus and modification its operation.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Experimental Investigation of the Horizontal Axis Wind Turbine with NACA4418 Blade Length
Autorzy:: Maulana, Muhammad Ilham
Syuhada, Ahmad
Hasan, Akhyar
Tematy:: wind energy
horizontal wind turbine
blade length
shaft rotation; Pokaż więcej
Wydawca:: Polskie Towarzystwo Inżynierii Ekologicznej
Powiązania:: https://bibliotekanauki.pl/articles/59113864.pdf Link otwiera się w nowym oknie
Opis:: Wind energy is a clean valuable source of renewable electricity when used with specific characteristically turbines because of its inexhaustibility as well as abating the use of fossil fuels. However, studies are still needed to design wind turbines with better performance. Therefore, this study aims to analyse the effect of blade length on the shaft rotation of a small-scale HAWT (horizontal axis wind turbine). A small-scale HAWT with the NACA4418 blade length of 1.25, 1.50, and 1.75 m was tested using three different blades (3, 4, and 5 blades) at speeds between 3 and 8 m/s without generating load. The lengths affected the tip speed ratio in this condition, considering various counts. The results showed that the rotor stability of a 1.25 m blade length was better than others at 4–6 m/s, based on the produced TSR value. The CP of the wind turbine also began to change significantly at 5 m/s, with the five-blade system of 1.25 m having the best rotation at medium speeds compared to others at 1.50 and 1.75 m. The correct number of blade lengths is essential for optimal and efficient overall turbine performance.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Agricultural Droughts Monitoring of Aceh Besar Regency Rice Production Center, Aceh, Indonesia – Application Vegetation Conditions Index using Sentinel-2 Image Data
Autorzy:: Sugianto
Rusdi, Muhammad
Budi, Muhammad
Farhan, Ahmad
Akhyar
Tematy:: drought monitoring
VCI
vegetation condition index
sentinel-2A
vegetation health index; Pokaż więcej
Wydawca:: Polskie Towarzystwo Inżynierii Ekologicznej
Powiązania:: https://bibliotekanauki.pl/articles/2202332.pdf Link otwiera się w nowym oknie
Opis:: Monitoring the agricultural drought of paddy rice fields is a crucial aspect of preparing for proper action in maintaining food security in Indonesia. The Aceh Province is one of Indonesia’s national rice production centers, especially Aceh Besar Regency; it includes three central districts; Indrapuri, Kuta Cot Glie, and Seulimeum. Satellite-Sentinel 2A data have been tested to monitor the drought levels of around 2,803 Ha in the three districts in this study. This study aimed to determine the drought level in Indrapuri, Kuta Cot Glie, and Seulimeum districts, Aceh Besar Regency’s paddy rice fields using Sentinel-2A data imagery. The vegetation conditions index (VCI) of Sentinel-2 data was utilized to identify a vegetative drought level in the area for the 2018, 2019, 2020, 2021, and 2022 growing seasons. The vegetation inertia index is derived from the Normalized Difference Vegetation Index (NDVI). The results show that the VCI looked volatile, but the trendline increased by four percent, from 92.56 in July 2019 to 96.08 in July 2021. Most areas on the dates investigated found that the no drought category was still dominant. The designated data analyzed found that the June 2022 data tend to be distributed to the drought in extreme, severe, moderate, and mild increases compared to the previous data investigated. This figure shows an increasing drought in the study area, and the average drought index is in the category of mild drought. In addition, there has been a trendline decline in the value of NDVI in recent years, causing agricultural land for paddy rice fields to be slightly vulnerable to drought.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: The effect of heat input on tensile strength, Vickers hardness, and microstructure on DMW of AISI 1015 and 304L SS through the GMAW process
Autorzy:: Riswanda
Akhyar
Kadir, H.
Sugianto
Saragih, A. D.
Tematy:: dissimilar metal welding
DMW
SS 304L
AISI 1015
heat input
tensile strength
Vickers hardness; Pokaż więcej
Wydawca:: Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Powiązania:: https://bibliotekanauki.pl/articles/59122532.pdf Link otwiera się w nowym oknie
Opis:: Purpose: This experiment was to evaluate the effect of heat input on tensile strength, Vickers hardness, and microstructural observations. Design/methodology/approach: The materials welded are AISI 1015 and 304L SS, and the joining process is Gas Metal Arc Welding (GMAW). The filler electrode used is ER70S-6 with a diameter of 1.2 mm, and the workpiece size is 300 x 125 x 3 mm with a butt-joint connection. The variations in welding current applied are 120, 130, and 140 A. Meanwhile, the voltage and welding speed in the experiment were kept constant. Findings: The maximum tensile test index was 380.08 MPa, and the Vickers hardness index was 376.85 HV, with the maximum heat input being 0.5943 kJ/mm. The macro- and microstructure, as well as structural inspection of the welded joints, were observed in the experiment. The best heat input effect for the DMW technique between 304L SS and AISI 1015 is 0.5943 kJ/mm at a plate thickness of 3 mm. Research limitations/implications: Dissimilar Metal Welding (DMW) is widely applied in the power generation industry. Materials generally joined using the DMW technique are austenitic stainless steel (304L SS) and low carbon steel (AISI 1015). Practical implications: Using the proposed heat input approach is important for the dissimilar welding industry application to obtain the right product for its expected use. Originality/value: This paper presents the differences in heat input to reveal the weld properties by dissimilar welding processes, where the properties will be adapted for a particular use. Particularly in the application of dissimilar joints between 304L SS and AISI 1015 with a thickness of 3 mm, which requires an average tensile strength of around 380.08 MPa and an average yield strength of about 320.16 MPa, the heat input parameter can be recommended as 0.5943 kJ/mm.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Analysis of inhibiting factors in shipyards in classterizing shipyards on the Northen coastal of ACEH Indonesia using the fuzzy AHP method: a preliminary study
Autorzy:: Rizwan, T.
Chaliluddin, M. A.
Nuvus, H.
Arif, M.
Muchlis, Y.
Akhyar, A.
Tematy:: data analysis
environment protection
fishing vessels
natural convection
human resources
shipyard
fuzzy
analytical hierarchy process; Pokaż więcej
Wydawca:: Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Powiązania:: https://bibliotekanauki.pl/articles/59123281.pdf Link otwiera się w nowym oknie
Opis:: The fishing shipyard in Banda Aceh City is a privately owned shipyard and is managed in a family manner. The shipyard here is active in carrying out maintenance, repair and construction of new ships when there is demand from consumers. Shipyards in Banda Aceh City generally make ships made of wood. The problem that is currently being faced is that there are many abandoned ships due to lack of finance, natural resources, human resources and the environmental, this is an obstacle to the progress and development of shipyards. The purpose of this study is to determine the inhibiting factors that exist in shipyards in the city of Banda Aceh and find alternative solutions to these problems. The method used in this study is a survey method used to look at existing symptoms and collect data on factors related to research variables and then analyzed using the Fuzzy AHP method. The results of this study indicate that the financial inhibiting factor is the most influential factor in shipyards with a resulting value of 0.4635, the inhibiting factor of Natural Resources is worth 0.35675, the inhibiting factor of Human Resources is worth 0.2865 and the inhibiting factor from the environment is the inhibiting factor which is the lowest or less influential with a value of 0.14325. The alternative solutions to financial problems are capital loans and investments. An alternative for natural resources is the addition of a minimum stock to anticipate stock scarcity and delays in the delivery of materials and tools. The alternative for human resources is the existence of an office, organizational structure, and division of tasks as well as awareness of occupational health and safety. As for the alternatives for the environment, namely the need for buildings or installation of tarpaulins for areas where ships are built, good land management and studies of other natural impacts.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Characteristics of Hybrid Biopellet based on Oil Palm Wood and Natural Activated Charcoal as a Renewable Alternative Energy Source
Autorzy:: Mawardi, Indra
Razali, Mawardi
Zuhaimi, Zuhaimi
Ibrahim, Akhyar
Akadir, Zaini
Razak, Hanif
Nurlaili, Nurlaili
Ginting, Ariefin
Ismy, Adi Saputra
Syarif, Jenne
Tematy:: oil palm wood
hybrid biopellet
natural activated charcoal
alternative energy source; Pokaż więcej
Wydawca:: Polskie Towarzystwo Inżynierii Ekologicznej
Powiązania:: https://bibliotekanauki.pl/articles/59113750.pdf Link otwiera się w nowym oknie
Opis:: Oil palm wood is biomass waste with a high abundance of energy which has the potential to be used as a raw material in the production of biopellet as an alternative energy source. However, oil palm wood possesses low density and calorific value. This study aims to evaluate the characteristics of biopellet formed through the hybridization of oil palm wood and natural activated charcoal. The natural activated charcoal filler was made from coconut shell and tapioca starch was used as a binder at a ratio of 150 g. Hybrid biopellet were produced using a roller wood machine with varying amounts of natural activated charcoal content: 200 g, 300 g, and 400 g per kg of raw material. The quality of the hybrid biopellet was evaluated based on the SNI 8021-2014 standards, including density, moisture content, ash content, volatile matters, fixed carbon, and calorific value. The results show that the hybridization of natural activated charcoal significantly influences the quality of the biopellets. Overall, the characteristics of the hybrid biopellet have met the SNI 8021-2014 standards, except for the ash content. The HBC-400 hybrid biopellet type exhibited the highest quality, with a density of 0.886 g/cm3, moisture content of 7.33%, ash content of 2.22%, fixed carbon of 62.12%, and calorific value of 4822 Cal/g. Oil palm wood and natural activated charcoal-based hybrid biopellet have the potential to be used as a renewable alternative energy source.
Dostawca treści:: Biblioteka Nauki

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