Showing papers by "Sebelas Maret University published in 2021"

Natural Fiber Reinforced Polymer in Automotive Application: A Systematic Literature Review

Abstract: Efforts to develop effective and innovative materials are increasingly being developed by researchers, especially in the development and utilization of NFRP (Natural Fiber Reinforced Polymer) in the automotive sector due to increased demand and increased ecological awareness. The purpose of this literature review article is to provide up-to-date information on the application of NFRP and plastic recycling in the automotive sector as well as consideration of selecting natural fibers for use as reinforcing composites in the automotive sector. This literature review focuses on the progress of the development of polymeric materials applied in the automotive field. Referring to defined inclusion and exclusion criteria, 30 articles in polymer composite studies published between 2015 and 2020 were selected for further investigation. The analysis of selected studies revealed that several leading car manufacturers have produced and developed products from NFRP or recycled plastics with natural fiber reinforcement because they are relatively cheap, lightweight, and able to reduce exhaust emissions. The great potential of using NFRP materials and recycled plastics in the automotive sector presents a future challenge, namely the increasing need for natural fiber in the long term which will certainly have an impact on ecosystems and biodiversity.

Internalisasi nilai-nilai luhur ajaran ki hajar dewantara dalam upaya pengembangan pendidikan budaya dan karakter bangsa

Abstract: ABSTRAK Ki Hajar Dewantara banyak meninggalkan nilai-nilai luhur. Nilai-nilai luhur tersebut amat relevan dengan pengembangan budaya Indonesia. Nilai-nilai luhur ajaran Ki Hajar Dewantara tersurat dan sangat bervariasi serta saling melengkapi antara satu dengan yang lain. Di dalam penelitian ini, dikaji internalisasi nilai-nilai luhur ajaran Ki Hajar Dewantara dalam upaya pengembangan pendidikan budaya dan karakter bangsa. Tujuan penelitian ini adalah 1) mendeskripsikan alasan-alasan mengapa perlu dilakukan internalisasi nilai-nilai luhur ajaran Ki Hajar Dewantara, 2) mengetahui kendala-kendala dalam pelaksanaan internalisasi nilai-nilai luhur ajaran Ki Hajar Dewantara, dan 3) menemukan strategi internalisasi nilai-nilai luhur ajaran Ki Hajar Dewantara dalam upaya pengembangan pendidikan budaya dan karakter bangsa. Penelitian ini menggunakan metode deskriptif dengan paradigma kualitatif. Teknik triangulasi digunakan untuk menjamin validitas data. Teknik analisis data menggunakan model analisis interaktif. Hasil penelitian menyimpulkan: 1) alasan-alasan mengapa perlu dilakukan internalisasi nilai-nilai luhur ajaran Ki Hajar Dewantara karena nilai-nilai ini bersumber dan sangat relevan dengan pendidikan budaya dan karakter bangsa, 2) kendala-kendala dalam pelaksanaan internalisasi nilai-nilai luhur ajaran Ki Hjar Dewantara dikelompokkan menjadi dua faktor yakni faktor internal dan eksternal, dan 3) strategi internalisasi nilai-nilai luhur ajaran Ki Hajar Dewantara dalam upaya pengembangan pendidikan budaya dan karakter bangsa dilakukan dengan strategi trilogi kepemimpinan. Kata kunci: internalisasi, Ki Hajar Dewantara, pendidikan budaya, pendidikan karakter ABSTRACT Ki Hajar Dewantara left many noble values which are well suited to Indonesian culture. The noble values of Ki Hajar Dewantara’s teachings as written in his works are varied and each complements the other. In this research will be studied the internalization of the noble values of Ki Hajar Dewantara’s teaching to developed culture education and nation character. The objective of this research are 1) to describe the reasons why it is necessary to internalize the noble values of Ki Hajar Dewantara’s teachings in the effort to developed culture education and nation character, 2) to find out the obstacles that arise from the internalization of the noble values of Ki Hajar Dewantara’s teachings in the effort to developed culture education and nation character, and 3) to find out how the internalization of the noble values of Ki Hajar Dewantara’s teachings in the effort to developed culture education and nation character. It used descriptive qualitative method. Triangulation technique was used to check the data validity. They were analyzed by using the interactive model of analysis. This research concluded were: 1) the reasons why it is necessary to internalize the noble values of Ki Hajar Dewantara’s teachings in the effort to developed culture education and nation character because the values is found from Indonesian surface, 2) the obstacles that arise from the internalization of the noble values of Ki Hajar Dewantara’s teachings in the effort to developed culture education and nation character are internal and external factors, and 3) how the internalization of the noble values of Ki Hajar Dewantara’s teachings in the effort to developed culture education and nation character with the leadership trilogies concept . Keywords: internalization, Ki Hajar Dewantara’s teaching, culture education, nation character.

Essential oils as growth-promoting additives on performance, nutrient digestibility, cecal microbes, and serum metabolites of broiler chickens: a meta-analysis.

Abstract: OBJECTIVE The purpose of this meta-analysis was to evaluate the effect of dietary essential oils (EOs) on productive performance, nutrient digestibility, and serum metabolite profiles of broiler chickens and to compare their effectiveness as growth-promoting additives against antibiotics. METHODS Peer-reviewed articles were retrieved from Web of Science, Science Direct, PubMed, and Google scholar and selected based on pre-determined criteria. A total of 41 articles containing 55 experiments with 163 treatment units were eligible for analyses. Data were subjected to a meta-analysis based on mixed model methodology considering the doses of EOs as fixed effects and the different studies as random effects. RESULTS Results showed a linear increase (p<0.001) on body weight gain (BWG) where Antibiotics (FCR) and average daily feed intake decreased (p<0.001) linearly with an increasing dose of EOs. Positive effects were observed on the increased (p<0.01) digestibility of dry matter, crude protein, ether extract, and cecal Lactobacillus while Escherichia coli (E. coli) population in the cecum decreased (p<0.001) linearly. There was a quadratic effect on the weight of gizzard (p<0.01), spleen (p<0.05), bursa of fabricius (p<0.001), and liver (p< 0.10) while carcass, abdominal fat, and pancreas increased (p<0.01) linearly. The dose of EOs linearly increased high density lipoprotein, glucose, protein, and globulin concentrations (p<0.01). In comparison to control and antibiotics, all type of EOs significantly reduced (p<0.001) FCR and tended to increase (p<0.1) BWG and final body weight. Cinnamaldehyde-compound was the only EOs type showing a tendency to increase (p<0.1) carcass weight, albumin, and protein of serum metabolites while this EOs together with EOs-Blend 1 decreased (p<0.01) E. coli population. Low density lipoprotein concentration decreased (p<0.05) with antibiotics and carvacrol-based compound when compared to the control group. CONCLUSION This evidence confirms that EOs are suitable to be used as growth promoters and their economical benefit appears to be promising.

Role of Cryogenic Cycling Rejuvenation on Flow Behavior of ZrCuAlNiAg Metallic Glass at Relaxation Temperature

Abstract: In this work, the effects of cryogenic cycling rejuvenation on the flow behavior of ZrCuAlNiAg metallic glass (MG) in the range of relaxation region from 0.7 up to 0.9 glass transition temperature (Tg) were investigated. For this purpose, nanoindentation and strain-rate jump tests were carried out to show the strain response of glassy alloy. According to the jump test, the increase in applied temperature leads to the rise in induced strain in both of as-cast and rejuvenated samples. It was also uncovered that the rejuvenated sample is sensitive to the higher strain rates leading to the significant overshoot in the flow stresses. In addition, the nanoindentation results indicated that the loading process induced a significant anelastic strain in the rejuvenated sample at 0.9Tg, demonstrating the possible formation and percolation of shear transformation zones (STZs) in the rejuvenated amorphous structure.

Performance comparison of TF-IDF and Word2Vec models for emotion text classification

Abstract: Emotion is the human feeling when communicating with other humans or reaction to everyday events. Emotion classification is needed to recognize human emotions from text. This study compare the performance of the TF-IDF and Word2Vec models to represent features in the emotional text classification. We use the support vector machine (SVM) and Multinomial Naive Bayes (MNB) methods for classification of emotional text on commuter line and transjakarta tweet data. The emotion classification in this study has two steps. The first step classifies data that contain emotion or no emotion. The second step classifies data that contain emotions into five types of emotions i.e. happy, angry, sad, scared, and surprised. This study used three scenarios, namely SVM with TF-IDF, SVM with Word2Vec, and MNB with TF-IDF. The SVM with TF-IDF method generate the highest accuracy compared to other methods in the first dan second steps classification, then followed by the MNB with TF-IDF, and the last is SVM with Word2Vec. Then, the evaluation using precision, recall, and F1-measure results that the SVM with TF-IDF provides the best overall method. This study shows TF-IDF modeling has better performance than Word2Vec modeling and this study improves classification performance results compared to previous studies.

Accurate and fast estimation for field-dependent nonlinear damping force of meandering valve-based magnetorheological damper using extreme learning machine method

Abstract: The application of artificial neural network (ANN) models in magnetorheological (MR) damper has gained interest in various studies because of the high accuracy in predicting the damping force, especially for control purposes. However, the existing neural network models have apparent drawbacks such as relatively long training time and the possibility to be trapped in local solutions. Therefore, this paper aims to propose a new method to deal with a highly nonlinear behavior of MR damper using an extreme learning machine (ELM) method. The ELM method is applied to a meandering valve-based MR damper for damping force prediction, which has been recently developed. A simulation scheme is selected with damping force as the output, and current, velocity, and displacement as the inputs. The simulations are then carried out based on fatigue dynamic tests data in various frequencies and currents. The training times for more than nineteen thousand data points using the ELM method with 10, 100, 1000 hidden neuron numbers are less than 1.70 s, which is faster than the conventional ANN. Based on 50 times training processes, the ELM and ANN models have comparable average accuracies with R2 values of more than 0.95. ELM also has shown less value R2 standard deviation showing its advantage to reduce the possibility of being trapped in local solution compared to the conventional ANN.

Carbon from Bagasse Activated with Water Vapor and Its Adsorption Performance for Methylene Blue

Abstract: This research work reports on the potential of bagasse, a solid waste from sugar factories, to produce activated-carbon (AC) as an adsorbent. The activation was conducted under 500, 600, and 700 °C using steam as the activation agent to produce AC500, AC600, and AC700, respectively. The prepared-materials were characterized to understand their elemental content, surface morphology, thermal properties, functional groups identification, surface area, and pore size. AC700 provided the highest surface area of 592.36 m2/g and indicated the contribution of mesopores distributes along 1.5–8.0 nm of pore size. Therefore, an adsorption test was conducted with AC700 as adsorbent. The results show that methylene blue (MB) adsorption reached equilibrium after 30 min of adsorption time. The adsorption isotherm applied to a monolayer Langmuir isotherm was fitted by linearization, resulting in a constant R2 of 0.999. The MB adsorption to AC700 favorably occurred, as proven by the Freundlich parameter 1/n of 0.881, which is less than 1. The Dubinin-Radushkevich isotherm confirmed that the adsorption proceeded through physical interaction with adsorption energy of 3.536 kJ/mol.

Factors Influencing Earnings Management in Railway Companies in Asia Pacific Region

Abstract: This study focuses on the factors that affect Earning Management in railway companies throughout the Asia Pacific, especially bonus plans, leverage, and government subsidies. These three factors are closely related to the characteristics possessed by the railway company. This research is quantitative using secondary data from the annual financial reports of railway companies in the Asia Pacific region from 2010 - 2019 with a sample size of 171 financial reports. The sampling technique was carried out using purposive sampling method. Modified Jones Model is used to measure earnings management. To test the hypothesis in this study using panel data regression analysis using the E-views 9 program. The results showed that the bonus plan has no effect on earning management. Leverage and government subsidies have a negative effect on earning management. Government subsidies have a positive effect on earnings management

Clarifying megaproject complexity in developing countries: A literature review and conceptual study:

Abstract: Complexity is considered one of the hallmarks of megaproject failure; however, no common definition of complexity in the megaproject context exists in contemporary literature; particularly in devel...

A Review: The Development of SiO2/C Anode Materials for Lithium-Ion Batteries

Abstract: Lithium-ion batteries are promising energy storage devices used in several sectors, such as transportation, electronic devices, energy, and industry. The anode is one of the main components of a lithium-ion battery that plays a vital role in the cycle and electrochemical performance of a lithium-ion battery, depending on the active material. Recently, SiO2 has garnered attention for use as an anode in lithium-ion batteries. SiO2 has a high specific capacity, good cycle stability, abundance, and low-cost processing. However, the high expansion and shrinkage of the SiO2 volume during lithiation/delithiation, low conductivity, and solid electrolyte interphase formation resulted in damage to the electrode structure and caused a decrease in SiO2 performance as an anode for a lithium-ion battery. The modified properties of SiO2 and the use of carbon materials as composites of SiO2 are effective strategies to overcome these problems. This review focuses on analyzing the role of various carbon materials in composite SiO2/C to enhance the performance of SiO2 materials.

Numerical solution strategy for natural convection problems in a triangular cavity using a direct meshless local Petrov-Galerkin method combined with an implicit artificial-compressibility model

Abstract: Thermal analysis of natural convection in a cavity is solved by numerical approach. The direct meshless local Petrov–Galerkin method combined with an implicit artificial-compressibility model is proposed here to simulate laminar natural convective heat transfer in triangular cavities. The spatial terms of the governing equation are discretized using the direct meshless local Petrov–Galerkin method with the Dirac function as the test function. The method uses an artificial-compressibility scheme to couple the pressure with the velocity components directly. The semi-algebraic system is solved using an implicit backward Euler pseudo-time method. Kovasznay flow problem is presented to examine the accuracy of proposed method. The validation of the obtained results by using experimental data is also provided, and four test problems — natural convection in an equilateral triangular cavity, a right-angled triangular cavity, an isosceles triangular cavity, and an irregular triangular cavity — are solved by using the proposed method. The numerical results obtained using the proposed method showed excellent agreement with those obtained using the conventional methods available in the literature.

The role of magnesium sulfate (MgSO4) in fetal neuroprotection.

Abstract: Prevention of neurologic disability associated with preterm birth is one of the major challenges in current perinatal medicine. Magnesium sulfate (MgSO4), the focus of this review has been proposed...

Exponential Smoothing on Modeling and Forecasting Multiple Seasonal Time Series: An Overview

Abstract: This paper presents the development process of the exponential smoothing (ES) model, starts with the traditional ES model and then focuses to the multiple seasonal ES model. This paper describes an...

Quality Of Physical Condition Of Youth Pencak Silat Athletes Reviewed From Speed, Power, and Strength

Abstract: The purpose of this study was to analyze the physical quality of youth pencak silat athletes in terms of speed, power and strength. The sample of this study was athletes Pencak silat category of young male and female numbered 40 people consisting of 20 male and 20 female. Sampling techniques use purposive samples because it considers the characteristics of age and gender. The quasi-experimental method with the quantitative approach used in this research, The constellation of this research is pretest-posttest one group design. Data analysis techniques use descriptive statistics and inferential statistics. Descriptive analysis aims to describe the characteristics of this research while inferential analysis using paired one sample test at a significant level ?= 0.05, overall data analysis used is SPSS program version 20.0. The results of this study showed that the quality of physical condition of athletes in the youth competition category is reviewed from speed, power, and strength in the good category. However, in this study, the need to further identify anthropometrics, and psychology athletes to determine the achievements of adolescent martial arts match categories according to gender characteristics.

Mapping the challenges in distance learning for students with disabilities during COVID-19 pandemic: survey of special education teachers

Abstract: The rapid spread of the Covid-19 virus has had an impact on various aspects of life, such as the economy, education, and socialisation. One of the social distancing policies in the field of education is the application of distance learning at the preschool, primary school, secondary school, special school, and college education levels. Its implementation has led to challenges for teachers, students, and parents, especially students with disabilities (SWD). The purpose of this study is to identify the challenges faced by the special education teachers (SETs) who have been providing distance learning for children with special needs during the Covid-19 pandemic. The study was conducted using a survey method by distributing questionnaires via Google Forms to 226 SETs in Indonesia. Data analysis was conducted using descriptive statistics. The results show that most of the SETs (66%) stated that they had faced barriers to distance learning that came from parents, students, and other teachers, as well as technical barriers. Accordin g to the SETs’ perceptions, some of the barriers that came from parents included lack of coordination and communication, limited use of mobile phones, and limited time for parents to accompany the students. The barriers coming from students were boredom and their lack of abilities. Furthermore, the barriers from the SETs themselves included difficulties in adapting material to online learning, difficulties in monitoring and evaluating student progress, and the lack of direction and coordination from schools. Other technical barriers were the frequent blackouts and insufficient internet signal.