bluuebunny/crossref_metadata_2025 huggingface dataset:
Designed Coastal Dike to Counter Natural Disaster of Big Waves at Toseho Village
Authors: Suyuti Suyuti , Misbah Zulkarnain K. , Ardhana Zhafirah M.
Published: May 2021

One of many cases of abrasion problemsin the coastal areais Toseho Village in South Oba subdistrict, North Maluku province. About thirty years ago, village residents have to evacuate to high land area due to abrasion damage that is caused by natural disaster of big waves from the pacific ocean. The abrasion progress is also triggered by deposit subsoil. By those problems, several families are still survived to stay because of living as fishermen, it is about 15 families. However, they do not have any construction to safeliving under attacking natural disasters. Therefore, this study is proposed a design method using empirical way to design a dike for countering the natural disaster in recovery area land. The tidal waves investigated by using Global Positioning System (GPS) and subsoil properties observed by practically way along the coastline of residential. The coastal dike has to design by considering stability criteria such as bearing capacity and factor of safety, which are conducted by several empirical equations. Finally, the results of field investigation for cross section about 30 meters on perpendicular direction to the coastline for along 483 meters are obtained different ground level average 2.0 meters at the coordinate of 0°20’57,91″U and 127°39’17,30″T. The subsoil identified as silty and sands materials at the ground surface, which is parameterof loose density. The simulation results of empirical way are obtained ultimate bearing capacity of the subsoil qu
of 31.2 t/m2, factor of safety for overturning Fs1 of 3.5 and factor of safety for sliding Fs2 of 1.8. Then, factor of safety for bearing capacity of subgrade Fs3 of 0.63, which is loaded by pressure at beneath the dike p of 49.74 t/m2.
Studied Internal Stability of Masonry Construction for the Fort Oranje Ternate
Authors: Suyuti Suyuti , Ibrahim Maulana , Imran
Published: May 2021

Based on information board data, the Fort Oranje Ternate founded in the year 1607. It was 412 years old, where Fort Oranje constructed by masonry with main materials of the coral river and coast marine with lime mortar. However, Fort Oranje at the south side was collapsed on August 24th, 2017. This research is to study the collapsing problem of the fort construction, authors were investigated in field and found a collapse area about 24 meters in length, and 5.7 meters in height. In visualization views show that fort construction failure due to internal stability indication. Therefore, to measure the physical and chemical parameters of Fort Oranje construction for calculation, authors are taken some mortar samples in the field, and bring it into laboratories. In which, mortar samples have to observe the quality by using a compression machine in Structure and material laboratory, chemical contents analyzed in the Chemical laboratory. Finally, the results of the compressive test machine for lime mortar are found on average about

σ
t
′

of 1.2 MPa and it is less than 19,9 MPa for normally mortar material with cement. Geometrical fort existing consisted of width at top b1
of 0.70 m, width at bottom b2
of 1.20 m, the total weight of masonry W of 108.3 kN. Then, soil fill parameters such as bulk density γs
of 17.2 ~ 19.2 kN/m3, internal friction φs
of 16.5°, cohesion c ≈ 0, and height hr
of 3.26 m. Finally, simulation results for height hk
= 3.26m ~ 3.9m are obtained factor of safety for overturning Fs1< 2.0, Meanwhile, a factor of safety for sliding Fs2 at the base are found Fs2 of 1.43 ~ 1.53. Moreover, Chemical content analyzed by XRF test method for the lime mortar sample is obtained by dominating Calcium Oxide (CaO) of 78.81%.
Corrugated Sheet Pile Analysis on Riverbank Retaining Wall Project in Factory Area of the Sukoraharjo Street
Authors: Triarso Arik , Risdianto Yogie
Published: May 2021

This retaining wall projects serves to hold the land close to the riverbank in the factory area of Sukoraharjo street, Malang. The height of the riverbank starting from the bottom of the river to the upper edge is around 7 m. The shape of sheet pile is determined using corrugated sheet pile. Calculation method using Plaxis 2D software. The stages of modeling in 2D Plaxis starts from determine the geometry of the soil profile and sheet pile. Then determine the input parameters of soil and sheet pile. After that determine the generate mesh opsi in the initial or existing geometry and conditions. After the procedure the calculation is done with the phases that have been determined. From the results of Plaxis 2D modeling and stability and strength analysis, that corrugated sheet pile type W - 500 Class B with a permanent permit moment of 299 kN m can be used as a retaining wall for riverbank with a height of 7 m in the factory area of Sukoraharjo street, Malang.. The depth of the corrugated sheet pile is embedded as deep as 7 m so that the total length of the sheet pile is 14 m. The safety factor value of the corrugated sheet pile stability is 2.98. This value is in accordance with the requirements of SNI 8460 - 2017.
Mathematical Model of Traffic Speed and Capacity in the Archipelago Base
Authors: Gaus A. , Muhammad T. Y. S. , Ambo U. S. H. , Liska N.
Published: May 2021

The transportation engineering developing who the application of the principal use planning, analysis and design to the disciplines comprising transportation: its vehicles, physical infrastructure, safety in travel, environment impacts and energy usage. The mathematical model in base archipelago was not much enough to research by transportation practiced. It had been of characteristic which different mainland. This paper using greenshields and greenberg models for approach real condition of the base archipelago. In the transportation involves working with the businessman, with industry, with citizen group, with elected officials, and with employes to the joint each segment of the public strip depended on at least one constructed facility. In this time there three components that included the discussion of the traffic of a microscop scale were flow, density and speed. At the greenshields model, the speed-density relationship show whose the value of speed higher than value of density lower with determination value 0,9755 where the curve of flow-density relationship show the value determination 0,8634 and for curva of flow-speed relationship showing whose maximum value of flow 1807 vehicles/hour at the value traffic speed 46 km/hour, traffic speed which at the lower or it the higher, so it condition given impact that the value of flow will going to low. on the other hand for greenberg model at speed-density relationship’s determination 0,9463, density-flow relationship show that the value minimum of density is 25 vehicles/km while value of flow is 1400 vehicles/hour and the relationship between flow-speed curve show that value maximum flow 1750 vehicles/hour with value speed 37. Base the value of each condition, so the greenshields model was better than greenberg model for this research. The mathematical model of the traffic flow which approach the real condition for the base archipelago was greenshields model.
Prototype of College Student Attendance Using Radio Frequency Identification (RFID) at Musamus University
Authors: Putra Nasra Pratama , Dolfi Loppies Stanly Hence , Zubaedah Reza
Published: May 2021

Student attendance in the classroom is one indicator for lecturers in learning activities. At Musamus University, student attendance has been managed digitally. The system is known as SIMAKAD. The weakness of SIMAKAD in doing attendance is in the process of entering data. Student attendance data can be inputted by the lecturer after completing the manual signature process by students. This can cause errors in entering data into the system. Whereas in the industrial revolution of the 4.0 era, the transformation of digital data in education was needed. For example, with the presence of Radio Frequency Identification (RFID) technology. The student attendance prototype using RFID was designed as a solution to solve problems in entering student attendance data at SIMAKAD. RFID technology can identify each student while attending college through reading the student TAG ID. By adding Internet of Things (IoT) capabilities, the results of reading student IDs will be sent directly through the internet and stored in a database server. The database can be directly used by lecturers as monitoring attendance of lectures. So no need to use manual absence.
Classification of Thesis Topics Based on Informatics Science Using SVM
Authors: Sari Rochman Eka Mala , Oktavia Suzanti Ika , Imamah  , Ali Syakur Muhammad , Anamisa Devie Rosa , Khozaimi Ach. , Rachmad Aeri
Published: May 2021

Thesis topic is an inseparable part in the world of tertiary education. Determining the thesis topic becomes a problem for students. The determination of the thesis topic leads to the trend of the topic in the development of computer science. The determination of the topic of thesis for students often ignores their ability to process. Ideally in determining the topic of the thesis, the record of student grades can be an important variable in deciding topics for students, where the student’s grade record is contained in the transcript. Therefore, this study uses the Support Vector Machine (SVM) method in recommending thesis topics by classifying selected subject groups that have been taken by students. The Support Vector Machine method is a classification method of supervision because it requires testing data and training data as a training process at the time of prediction. Support Vector Machine provides an optimal model, which provides a solution with a maximum margin to determine the distance of data to the hyperplane. The test results show an accuracy of 80%.
Implementation of Web Server Security Against Denial of Service (DoS) Attacks
Authors: Idhom Mohammad , Alit Ronggo , Fauzi Akhmad
Published: May 2021

Denial of Service (DoS) is one of the top cyber-attacks that grows exponentially attacking every company, agency, and organization with a percentage of 43%. This type of attack has the most damage to business operations and affects globally. By flooding the bandwidth or resources of a machine or system, attackers deny it so that legitimate users cannot access the service. The objectives of this study are: 1. Creating a security system on a web server against Denial of Service (DoS) attacks that are applied to containerization architecture. 2. Implementation of load balancing methods for securing the web server from Denial of Service (DoS) attacks. 3. Implementing the deployment process and monitoring the web server in the containerization architecture. The results of comparisons and testing of services carried out with denial of service attacks prove that the memory load used by a web server with containerization architecture is less than that of conventional web servers. Testing was also carried out on hardware performance, namely CPU. Conventional web servers are heavier by up to touching 0.00015% compared to web servers with the highest containerization architecture, only touching 0.00010%.
Phased-MIMO Radar : Angular resolution
Authors: Reza A , Muttaqin H , Miftachul U
Published: May 2021

Phased-MIMO is very suitable for multi-target detection such as radars for bird migration, radars for autonomous cars, fish radars and others. The problem is the ability of radar to distinguish the first target, the second target and the next target. This study reports the ability of Phased-MIMO radars to be able to distinguish two or more objects that are close known as angular resolution of radar.
Performances Combination Schemes AES-Turbo Code Based-on Keys Length
Authors: Kuswanto Dwi
Published: May 2021

In data communication the process of sending data in the form of information is susceptible to theft, destruction, modification or repetition of the data sent which causes information to be changed / corrupted according to the original data. One way to guarantee authenticity can be done by utilizing security techniques in the process of sending data, one of which is by using a combination of cryptographic and error correction techniques, namely AES and Turbo Code. This study aims to combine the two techniques and apply them to text data by evaluating based on the length of AES encryption keys. Performance results indicate that AES-Turbo cryptographic combination algorithms can work optimally at SNR greater than or equal to 15 dB, for the best test value for avalanche effects is 24.77 % at 256-bit key lengths and the testing data execution time with an average time of 9.19 seconds, the time required for decryption is longer than the time needed for encryption, and the longer the key the longer it takes for encryption and decryption. For selection of keys length of AES more efficiency and effectiveness that is by using 128-bit key.
An Empirical Study to Validate The Technology Acceptance Model (TAM) In Evaluating “Desa Digital” Applications
Authors: Andy Raditya , Dewi Alina C , As’adi M
Published: May 2021

The sustainability of Industry 4.0 has now entered into the tourism sector or Tourism 4.0. Where tourism in Indonesia is a potential thing but still not as expected. Previous research shows that the applied model has not yielded optimal results in predicting platform use, so one of the steps to further study the Desa Digital mobile application research is done with the variables used in this study: Perceived Ease of Use, Perceived Usefulness, Attitude Toward Use, Intention to Use, and Actual System Usage. The aim of this research is to know the technology acceptance variable using the Technology Acceptance Model (TAM) and evaluate it. The method used in this research is to use the Partial Least Square (PLS) method. The results showed that: (1) variables influencing the acceptance of the Technology Acceptance Model, namely: Perceived Ease of Use, Perceived Usefulness, Attitude Toward Use, Intention to Use and Actual System Usage, (2) constructs that affect the model namely Perceived Ease of Use Use and Perceived Usefulness for Attitude Toward Use, Attitude Toward Use for Intention to Use and Intention to Use for Actual System Usage.
E-readiness Measurement in the Virtual Application Learning
Authors: Wibawa Rindu Puspita , Wibawa Setya Chendra , Susanti Martini Dwi Endah , Sulistiyo Edy
Published: May 2021

Indonesia in the early 2020s was being rocked by the outbreak of Coronavirus Disease (Covid-19) which hit almost all parts of the world. Indonesia spontaneously implements a policy of learning from home (SFH) and working from home (WFH). Higher education during the WFH period needs to strengthen online learning. Universitas Negeri Surabaya has had e-learning developed using Moodle LMS and has been used as a form of learning called Vilearning Unesa (Vinesa). The research aims to measure the implementation readiness of Vinesa. This measurement needs to be done as an effort to support the successful development of e-learning. To know which factors are still weak and require improvement and which factors have been considered successful or strong in supporting the implementation of Vinesa. There are eight indicators used to measure the readiness of e-learning, namely the psychological readiness, sociological readiness, environmental readiness, human resource readiness, financial readiness, technological skill readiness, equipment readiness, and content readiness. However, this research focuses on one indicator that is directly related to students, namely content readiness. The research method used is qualitative research methods. The study began with a literature study on e-learning readiness. Then an indicator is set to be reduced to the items in the questionnaire. The object of research is students of Informatics in Universitas Negeri Surabaya.
Temperature Reduction to Enhancing Solar Panel Performance in Tropical Climate
Authors: Dasrun Deliana , Petrana Subhan , Wahab Iis Hamsir Ayub
Published: May 2021

The characteristics of climate in a region also influences the performance of solar panels, the characteristics are the intensity of solar irradiance, temperature, wind speed and humidity. An evaluation of the performance of solar panels needs to be done regarding the tropical climate in Indonesia. This evaluation is needed to determine how large the resulting energy production that will be used for the benefit of both technical and investment for Solar Power Plant. The purpose of this study was to examine the effect of wood powder composite board material in reducing the surface temperature of solar panels in order to increase the efficiency of energy conversion. The type of solar panel used is 50 Wp Polycrystalline. The results showed that the average of solar radiation is at 690 W/m2 resulting in an average current value of 1.8 A (with board dampers) and 1.68 A (without the board damper). While the average temperature of a solar panel without a damper is 36.4 ° C while the damping board drops to 34.6°C. Consequently increasing the output voltage level from 20,38 V to 20,55 V, This change also results in an increase in output Solar panel power on average from 47,8 Wp (without damper board) to 48,2 Wp (with damper board), with a reduction in power losses from 2,3 Wp to 1,8 Wp.
The SNR Performance of Cooperative Diversity in HF Skywave Communication Systems
Authors: Said Muhammad , Do Saiful , Abdullah
Published: May 2021

High Frequency (HF) communication systems uses the ionosphere to reflect signals from the source (S) to the destination (D) on earth. Variation of the height of the earth’s ionosphere layer causes the received signal also to fluctuate and affects the signal-to-noise ratio (SNR) at the destination. To maintain the SNR remains good value at the destination, cooperative communication system can be a solution. In cooperative communication system, all sources cooperate and coordinate with the relay (R) to improve the quality of the signal at the destination. In this communication system, the destination receives two signals, each derived from source and from relay. This paper divides the simulation observation time into 3 categories, namely midnight to dawn (00:00 and 04:00), morning to noon (08:00 and 12:00) and afternoon to evening (16:00 and 20: 00). In all categories of midnight to dawn, morning to noon and afternoon to evening, cooperative communication systems with maximal ratio combining (S - R - D) provide greater diversity gain than non cooperative communication systems (S - R - D).
Analysis of the Aircraft Guide Signal Interference in Mopah Airport
Authors: Corputty Roberto , Kaikatui R N , Muriani
Published: May 2021

Doppler Very High Omnidirectional Range(DVOR) is one of aviation navigation equipment which is in Mopah Airport which serves the best mamandu from and to the airport of destination. One recent years specifically the year 2018, there were complaints (criticism) of the pilot on beam interruption that caused it to equipment OBS (Omni-Bearing Selector) that there dipesawat not get an accurate azimuth as data information to the pilot could lead destination ground station where the airport is located. The method used is descriptive analysis method which describes the behavior of DVOR equipment, the environment around the equipment by using data that is processed by comparing the calculation parameters (antennas, transmit power, antenna gain, antenna sideband doppler effect, doppler effect) DVOR. The purpose of this research to know the influence of DVOR navigation equipment of the aircraft and determine the cause reception interference signals containing azimuth information to the pilot to find the destination airport. The result of the calculation parameters of the antenna with the speed of the sideband antenna 4147.7 feet per second to transmit power, gain and doppler effect that according to the standard equipment is the working frequency of 115.8 MHz to DVOR Mopah Airport so that the results obtained on the degree of 270-290 best get the signals radiated by the azimuth angle information is not accurate bearing caused by the emission of DVOR equipment obstructed by building new UPBU on Mopah Airport.
10 Segment Spiral Antenna to Measure Partial Discharge on High Voltage Equipment
Authors: Laksono Deni Tri , Laksono Dedi Tri , Ulum Miftachul , Oktavia Suzanti Ika
Published: May 2021

Electricity basically has become the main requirement for human beings on earth. Thus electrical reliability is the most important things so that electricity flow to consumers is not interrupted. The most electricity vital is substation, there are some disturbances that commonly occur in high voltage equipment in substation such as disruption due to old tool, interference due to human error, and natural disruption resulting in equipment damage. To minimize these disturbances we need a tool that can detect interference, namely sensors. One of disturbances in substations is Partial discharge. To find out a partial discharge in voltage equipment there are several ways such as measuring using a RC sensor detector and using an antenna. This study discusses partial discharge sensor that will detect the level of partial discharge that exists in high voltage equipment such as transformers, cables, GIS (Gas insulated switchgear) and others. Spiral antenna is the main topic in this research by making spiral antenna with 10 segments. The steps in making this antenna are firstly carried out design and simulation using CST 2018 software then implementing antenna on FR4 epoxy PCB. The antenna is tested for its characteristics based on several parameters such as VSWR, RL, and Bandwidth. This test is carried out using a VNA measurement tool. The test results show that this 10 segment spiral antenna produces a VSWR value of less than 2, an RL value of less than -15, and bandwidth included in signal frequency by partial discharge is around 300MHz - 3GHz.
A Study on the Use of Powder Zeolite as Backfill Material for Single Rod Grounding System
Authors: Sitorus H B H , Permata D , Wicaksono A
Published: May 2021

One way to reduce the value of grounding resistance is to replace the electrodes’ backfill material with other materials such as; gypsum, charcoal powder, and bentonite. In this paper we report the use of zeolite powder as a backfill material to bury the electrodes of the grounding system. The purpose of this research is to compare zeolite and pure soil to be used as a backfill material. The type of electrode used is a single rod electrode. The parameters measured were grounding resistance, rain intensity, moisture and pH of the backfill material. Measurements were taken every day for 30 days. It was found that zeolite as a backfill material is better than pure soil which is often used so far. It is seen that the resistance value of grounding system using rod that buried in zeolite as a backfill material is lower than a half of the resistance value of grounding system when using pure soil as a backfill material. From this research it was also found that the moisture of the backfill material was higher by using zeolite than pure soil.
Design of IoT-Based Smart Bins Integrated Monitoring System Using Blynk
Authors: Juwariyah T , Krisnawati L , Sulasminingsih S
Published: May 2021

Waste management has always been an important topic of studies. One of the efforts to handle waste in the Era of Industrial Revolution 4.0 was to start by designing a smart bin. The purpose of this study is to design an integrated monitoring system of several IoT-based smart bins. The hardware and software components used in system design were Wemos D1 Mini Pro Microcontroller, HC-SR04 ultrasonic sensor, DHT22 temperature-humidity sensor, Blynk and Arduino IDE. Blynk was used in building an integrated monitoring system for several garbage bins. In this study two samples were monitored through the Blynk application. The height value of the garbage was measured by an ultrasonic sensor while the humidity and temperature values were measured by the DHT22 sensor. In realtime, every measurement results of rubbish height, temperature and humidity were displayed by the Virtual Level of Blynk application on the smartphone. Graphical measurement results could also be displayed on Blynk.
Quality of drinking water sources in Sarmi Regency, Papua Province
Authors: Parlindungan J Y , Sumanik N B , Pongkendek J J , Rettob A L
Published: May 2021

In general, rivers in Sarmi still in their natural state. Those rivers have considerable discharge during the rainy season and decreased dramatically during the summer. Many rivers are used for domestic purposes such as bathing, washing and other needs in small amounts. Yet there is a river that is used on a large scale as a source of water for industrial activities. Of all the rivers which are the object of monitoring, there is no industry that directly generates large volumes of waste and channeled into the river. In some parts of the river, there are also residential areas, but there is no population growth that causes the expansion of settlements along the banks of these rivers. The sampling method used is grabbed samples. Some things to consider in the course of this sampling include: (1) Water samples taken are representative and reliable; (2) The volume of the sample taken in accordance with the minimum amount required. In general, any method of analysis used chemical parameters has limits specified rate. This is related to the power limitations of each method and measuring equipment used. In that regard, then the chemical analysis is often performed dilution or concentration, with the aim to improve measurement accuracy. The results of the study for water sources used by the community in the sarmi district of Papua Province showed that the values of the measurement results still meet the quality standards for first-class water quality Republic of Indonesia Government Regulation No. 82 of 2001, which is intended for drinking water, water recreation, freshwater fisheries, animal husbandry, and planting. Therefore this quality needs to be maintained by the community by protecting the environment and by the government as a partner by making regulations related to environmental preservation.
The Knowledge Inheritance System of Building Kombai Tribe’s Tree House in Boven Digoel
Authors: Hematang Y I P , Pamuttu D L
Published: May 2021

In the process of inheriting knowledge about building a Tree House, the Kombai Tribe in Boven Digoel applies a hereditary system in which the younger generation is directly involved in the construction of houses. The knowledge and skills to build a Tree House do not go through special training or education but are self-taught from parents to children. The process of building house also uses mutual cooperation system between residents within the village or between residents within one clan. But over time, it is known that there are some dilemmas or obstacles in passing down this knowledge. This dilemma then becomes an obstacle in preserving the Tree House. This study aims to determine the knowledge inheritance system of building the Tree House and what obstacles are experienced by the Kombai Tribe in preserving the Tree House in the city. This study uses an inductive approach with descriptive survey method.
Study of Utilization Plastic Waste as Basic Material for Boat Manufacturing Using Eco-green Design Concept
Authors: Noverdo S , Iswadi N , Reda R , Bambang S , Muayyad P.
Published: May 2021

The plastic waste problem has become a global problem and the effect on the environment is horrible.

Almost all countries make an effort to reduce their daily utilization. Environmental organizations and researchers are also performing research to find ways to recycle plastic waste. In this paper introduces the “Eco-green Design Concept” to utilize plastic waste (type 2) as fishing boat material. This concept will recycle 3 tonnes of plastic waste into the material of a fishing boat. In addition, the implementation element of eco-green design concept (design quality (D), Environmental Friendly (E), Eco-green Material (G)) into the design of fishing vessels has been successful. The concept does not only utilize type 2 plastic waste into the hull of the ship, but the design of the ship is made to have small resistance, good stability and has a large cargo area. And also has a machine that is environmentally friendly and does not cause pollution.
Steady State Simulation of a CO2 Heat pump system for Water Heating
Authors: Rais Sandi , Murayama Katrunori , Hasegawa Tatsuya
Published: May 2021

A steady state simulation model for a CO2 heat pump system was developed in order to evaluate system performance of water heating. A simple Macro Excel coding was develop to calculate the refrigerant condition in the heat pump pipe. The REFFPROP 8.0 also use to find initial value of the pressure, enthalpy and refrigerant characteristic. The Macro Excel and REFPROP 8.0 was developed by linked both programme because it provide a similar features. The simulation was compared with experimental data of a laboratory scale CO2 heat pump system. The pressure and temperature estimated by simulation were found to be approximately within 10% error between simulation and experiment. The COP obtained from the simulation was higher than that obtained by experiment and it was reduce as the effect of the mass flow rate of the refrigerant reduction for the performance analysis by the change of the closing angle of expansion valve.
Reducing Emissions CO, CO2, and HC, on Vehicles with Gasoline Fuel
Authors: Cipto  , Rahangmetan Klemens A , Sariman Farid , Parenden Daniel , Christian W Wullur
Published: May 2021

Merauke Regency is the largest regency in Papua with the highest fuel consumption by regency/city in Papua Province. The high fuel consumption is proportional to the emissions produced, so research on emissions absorbing media is needed to reduce emissions. Active charcoal has the ability to adsorption of emissions, one of the raw materials is plants. Bus wood (eucalyptus) which grows a lot in Merauke can be used as raw material for activated charcoal which is used as an absorber of emissions. Research with the title “application of eucalyptus charcoal as emission adsorbent to reduce vehicle exhaust emissions” processes wood logs into emission adsorbents, through carbonation and activation processes, then activated charcoal is applied to vehicle vehicles and subsequent emission tests, to determine emission reduction capabilities. Based on the results of emission tests, the use of activated charcoal as an emission adsorber can reduce emissions. 0.07% CO emissions decreased to 0.01%, HC emissions 84 ppm, decreased to 39 ppm, and 14.7% CO2 decreased 4.4%.
Effect of Holding Time and Cooling Media on Heat Treatment Process to Gear Motor Indopart Hardness
Authors: Rahangmetan Klemens A. , Cipto  , Wullur Christian W. , Parenden D , Sariman Farid
Published: May 2021

Industrial and technological advancements are growing rapidly, closely related to various machine tools, including the metal and construction industries. In the field of machinery many metal elements such as steel are involved. The progress of the metal industry has an important role, especially in the automotive world which uses a lot of metal materials. Therefore an attempt arises to change its mechanical properties in order to change the level of violence. This study aims to determine the level of medium carbon steel hardness (indopart gear motor), and determine the interaction between the two variables and determine the most optimal level of hardness. The method used in this study is the method of observation and literature on the fundamental theories, the sample used in this study is medium carbon steel (indopart gear motor) which is heat treated with a holding time of 60 minutes, 120 minutes and 180 minutes and with water, oil, diesel and air cooling media. Then hardness testing is done. Based on the results of the analysis of the data obtained there is a significant difference in the effect of the average cooling media on the level of violence, there is no significant difference in the effect on the average hardness between the holding time, there is a difference in the effect of the interaction between the holding time and the cooling media. The optimal treatment process is where the holding time is for 180 minutes using water media.
Effect of Ti/SiC Reinforcement on AA5083 Surface Composites Prepared by Friction Stir Processing
Authors: Rahman Ziyaur , Siddiquee Arshad Noor , Khan Zahid A.
Published: May 2021

Al alloys because of their desirable characteristic properties have made them predominant materials in lightweight design structures such as the aviation, automotive, and shipbuilding industry. However, their applications are limited due to their lower strength at higher operating temperature and difficulty in their welding. One of the alternatives to enhance the surface properties of aluminium alloys is coating metallic substrates. In the present experimental study, the effect on surface properties by introducing titanium and silicon carbide reinforcement into AA5083 alloy using friction stir processing (FSP) was investigated. Additionally, bead geometry such as the width of SZ, depth of SZ, and area of SZ in all the specimens were also analyzed. FSP was performed at different combinations of rotational speeds, traverse speeds, and shoulder diameter sizes using Taguchi L4 orthogonal array. Experimental results indicated that the highest value of hardness was observed at tool rotational speed of 355 rpm, traverse speed of 63 mm/min, and shoulder diameter size of 17 mm. Moreover, at such combination of process parameters, the lowest value of width to depth ratio was observed.
Pipe Stress Analysis of Pump System in Process Plant
Authors: Jha Akhilesh Kumar , Kennedy S , Jha Kamlesh Kumar
Published: May 2021

Every process and LNG plants operate many pumps and compressors in the processing unit. Performing the pump stress Analysis is immensely critical. The Pump’s high vibration on the process plant will seriously affect the pipe and equipment’s smooth operation. The resonance effect between pipe and equipment will create a severe additional desecration. Before installation or formal process, we need to perform static analysis, and dynamic analysis (modal, forced response analysis) is mandatory for the pump system. The pump vendor must perform a Pulsation analysis on the piping system for reciprocating machinery subject to pulsation flow. In this study, flexibility analysis of pump piping system as per process piping code B31.3 using CAESAR-II programming followed by placing of diverse pipe supports. The support type and position of the supports as per the output get from static and dynamic examination. By the software analysis of CAESAR II, the efficiency of pipe flexibility and expansion of the piping system’s natural frequency is authenticating by include more oriented and load-bearing support to the elbow and Valve, which prevents the resulting of resonance successfully. The stress analysis, modal analysis, pulsation analysis, and vibration analysis method proposed in this paper will increase the lifespan and operation reliability of pipe and equipment.
Analysis of flow stress and microstructure evolution of 9310 steel during the hot compression
Authors: He YuHui , Lu Shuang , Tang JinYuan , Zhang JiaJia
Published: May 2021

Due to the low-cost and high-strength of carburizing 9310 steel, it has become widely used in the manufacturing industry especially gears and shafts manufacturing. Hence, this paper investigates the hot deformation behavior and microstructure evolution of the 9310 steel under hot compression conditions. With the help of a combination of standard compression testing, optical microstructure and electron backscatter diffraction (EBSD) observation experiment, the dynamic recrystallization (DRX) and dynamic recovery (DRV) mechanisms of the 9310 steel under compressive stress were determined and the constitutive equation model was also identified. It was found that the peak stress level, steady flow stress, dislocation density and number of substructures of the alloy increases with the decreasing of deformation temperature and the increasing of strain rate. Conversely, the high angle grain boundary area becomes larger, the grain boundary forms a serrated shape and the DRX in the alloy occurs. This comprehensive characterization of stress and phase transformation could enable a precise control of the microstructures of 9310 steel, and hence its properties.
K-stability of log Fano hyperplane arrangements
Authors: Fujita Kento
Published: May 2021

In this article, we completely determine which log Fano hyperplane arrangements are uniformly K-stable, K-stable, K-polystable, K-semistable, or not.
Do flowers removed of either nectar or pollen attract fewer bumblebee pollinators? An experimental test in Impatiens oxyanthera
Authors: Li Deng-fei , Yan Xian-chun , Lin Yi , Wang Li , Wang Qiong
Published: May 2021

Pollen and nectar are the primary rewards offered by flowers to pollinators. In floral visitors of some plant species, pollen thieves and nectar robbers cause the reduction in pollen grain number and nectar volume, respectively. However, it remains unclear whether the absence of either of the two rewards in a given flower reduces its attraction to nectar- and pollen-collecting pollinators. We hypothesized that flowers removed of either nectar or pollen would attract fewer pollinators. We studied protandrous Impatiens oxyanthera, whose flowers provide bumblebee pollinators with both nectar and pollen in the male phase. We conducted floral reward manipulation experiments to explore how the removal of either nectar or pollen from flowers influences pollinator behaviour by comparing their visitation rates and visit duration. Compared with the control flowers, the flowers removed of pollen attracted significantly more bumblebee pollinators per 30 min, but the flowers removed of nectar or those removed of both pollen and nectar attracted significantly fewer bumblebee pollinators per 30 min. Moreover, the visit duration of bumblebee pollinators to control flowers or flowers removed of pollen was longer than that to flowers removed of nectar or those removed of both pollen and nectar. Our investigations indicated that compared with control flowers, the flowers removed of nectar attracted fewer bumblebee pollinators, supporting our hypothesis. However, our other hypothesis that pollen removal would reduce pollinator visits was not supported by our results. Instead, compared with control flowers, the flowers that contained only nectar attracted more bumblebee pollinators. Nectar seems to be the main reward, and bumblebee pollinators mainly used the absence of pollen as a visual signal to locate I. oxyanthera flowers with a potentially higher amount of nectar.
Fate of Fat Grafting In Vivo and In Vitro: Does the Suction-Assisted Lipectomy Device Matter?
Authors: Hsiao Hui-Yi , Lai Chao-Yi , Liu Jia-Wei , Yu Yuan-Yuan , Chang Frank Chun-Shin , Huang Jung-Ju
Published: May 2021

Background

Recently, there has been increasing research interest in identifying the effect of liposuction procedures on fat graft survival in order to clarify whether different harvest techniques affect the quality of fat grafts.

Objectives

The aim of this study was to investigate the effect of 2 liposuction methods on the survival and regeneration potential of grafted fat tissue. The proliferation and differentiation potentials of adipose-derived stem cells (ASCs) isolated by both methods was also investigated.

Methods

Fat grafts were collected from patients who underwent liposuction procedures by 2 different methods: traditional suction-assisted liposuction (TSAL) and vibration amplification of sound energy at resonance (VASER). One portion of the lipoaspirates was implanted into the subcutaneous layer of nu mice for 4 and 12 weeks. ASCs were isolated from the other portion of the lipoaspirate and subjected to proliferation and differentiation assays.

Results

Although in vivo fat grafting presented similar adipose tissue survival for the 2 different liposuction methods, more angiogenesis and less fibrosis was observed in the VASER group based on histologic evaluation. Furthermore, VASER-derived ASCs presented better quality in terms of cell differentiation capacity.

Conclusions

The in vivo study confirmed better graft angiogenesis with less inflammation, apoptosis, and scar formation in the VASER group. ASCs harvested with VASER exhibited increased differentiation capacity compared with those obtained by TSAL, and represent an excellent source for fat grafting and regenerative medicine.
Single-cell multi-omics sequencing: application trends, COVID-19, data analysis issues and prospects
Authors: Huo Lu , Jiao Li Jiao , Chen Ling , Yu Zuguo , Hutvagner Gyorgy , Li Jinyan
Published: May 2021

Single-cell sequencing is a biotechnology to sequence one layer of genomic information for individual cells in a tissue sample. For example, single-cell DNA sequencing is to sequence the DNA from every single cell. Increasing in complexity, single-cell multi-omics sequencing, or single-cell multimodal omics sequencing, is to profile in parallel multiple layers of omics information from a single cell. In practice, single-cell multi-omics sequencing actually detects multiple traits such as DNA, RNA, methylation information and/or protein profiles from the same cell for many individuals in a tissue sample. Multi-omics sequencing has been widely applied to systematically unravel interplay mechanisms of key components and pathways in cell. This survey overviews recent developments in single-cell multi-omics sequencing, and their applications to understand complex diseases in particular the COVID-19 pandemic. We also summarize machine learning and bioinformatics techniques used in the analysis of the intercorrelated multilayer heterogeneous data. We observed that variational inference and graph-based learning are popular approaches, and Seurat V3 is a commonly used tool to transfer the missing variables and labels. We also discussed two intensively studied issues relating to data consistency and diversity and commented on currently cared issues surrounding the error correction of data pairs and data imputation methods. The survey is concluded with some open questions and opportunities for this extraordinary field.
Climate instability causing the decline of a Neotropical savanna lizard population (Squamata: Tropiduridae)
Authors: Caetano Gabriel Henrique De Oliveira , Colli Guarino Rinaldi
Published: May 2021

Populations that evolved in predictable seasonal environments might not have mechanisms to deal with unpredictable climate change. Assessing whether these populations can cope with recent increases in climate extremes and variability can better inform conservation efforts. We investigated the effects of climate deviations and fire on the population dynamics of the lizard Tropidurus torquatus in the Cerrado of Brazil. We decomposed six climate variables into seasonal and non-seasonal components and assessed which factors, along with long- and short-term effects of fire, better accounted for variation in the survival and recruitment of a T. torquatus population monitored for 12 years. Survival was not associated with climate seasonality, and instead minor fluctuations were related to temperature extremes. Recruitment benefited from long-term fire effects and had a strong seasonal component accounting for most of the variation in the population. Climate deviations caused severe changes in the number of recruits each year, with an overall negative effect on population growth. Population growth was more sensitive to recruitment than to survival, resulting in a sharp population decline over the study period. Tropidurus torquatus, and perhaps other species that evolved in similar conditions, can mitigate the demographic effects of fire but lack mechanisms to deal with climate deviation occurring over relatively short periods.
Vascular histopathology and connective tissue ultrastructure in spontaneous coronary artery dissection: pathophysiological and clinical implications
Authors: Margaritis Marios , Saini Francesca , Baranowska-Clarke Ania A , Parsons Sarah , Vink Aryan , Budgeon Charley , Allcock Natalie , Wagner Bart E , Samani Nilesh J , von der Thüsen Jan , Robertus Jan Lukas , Sheppard Mary N , Adlam David
Published: May 2021

Aims 

Spontaneous coronary artery dissection (SCAD) is a cause of acute coronary syndromes and in rare cases sudden cardiac death (SCD). Connective tissue abnormalities, coronary inflammation, increased coronary vasa vasorum (VV) density, and coronary fibromuscular dysplasia have all been implicated in the pathophysiology of SCAD but have not previously been systematically assessed. We designed a study to investigate the coronary histological and dermal collagen ultrastructural findings in SCAD.

Methods and results

Thirty-six autopsy SCAD cases were compared with 359 SCAD survivors. Coronary and myocardial histology and immunohistochemistry were undertaken. Transmission electron microscopy (TEM) of dermal extracellular matrix (ECM) components of n = 31 SCAD survivors and n = 16 healthy volunteers were compared. Autopsy cases were more likely male (19% vs. 5%; P = 0.0004) with greater proximal left coronary involvement (56% vs. 18%; P < 0.0001) compared to SCAD survivors. N = 24 (66%) of cases showed no myocardial infarction on macro- or microscopic examination consistent with arrhythmogenic death. There was significantly (P < 0.001) higher inflammation in cases with delayed-onset death vs. sudden death and significantly more inflammation surrounding the dissected vs. non-dissected vessel segments. N = 17 (47%) cases showed limited intimal fibro-elastic thickening but no features of fibromuscular dysplasia and no endothelial or internal elastic lamina abnormalities. There were no differences in VV density between SCAD and control cases. TEM revealed no general ultrastructural differences in ECM components or markers of fibroblast metabolic activity.

Conclusions 

Assessment of SCD requires careful exclusion of SCAD, particularly in cases without myocardial necrosis. Peri-coronary inflammation in SCAD is distinct from vasculitides and likely a reaction to, rather than a cause for SCAD. Coronary fibromuscular dysplasia or increased VV density does not appear pathophysiologically important. Dermal connective tissue changes are not common in SCAD survivors.