Showing papers by "Sebelas Maret University published in 2014"

An Empirical Examination of Individual and System Characteristics on Enhancing E-Learning Acceptance.

Abstract: Due to the continued prevalence of e-learning underutilization in Indonesia’s higher education context, this study empirically examines individual and system characteristics believed to influence students’ acceptance of e-learning systems. The proposed research model is developed to examine the influence of five characteristics of the Technology Acceptance Model using the Structural Equation Modelling technique. This study found that both individual characteristics, computer self-efficacy and internet self-efficacy, play an important role, indirectly affecting perceived intention to use e-learning. The system characteristics including learning content and technology accessibility have been found to significantly influence learners’ acceptance behaviours. Both perceived ease of use and perceived usefulness were found to be significant predictors of perceived intention to use. Additionally, perceived usefulness was found to have more predictive power than perceived ease of use on behavioural intention to use. This study contributes to a better understanding of how to enhance e-learning acceptance through improvement in individual and system characteristics.

A high performance magnetorheological valve with a meandering flow path

Abstract: The huge developments in the field of magnetorheological (MR) fluid-based devices will have a great influence on the future of mechatronic applications due to the ease of interfacing between electronic controls and the mechanical components that they provide Among various MR fluid-based devices, an MR valve would be particularly significant for the development of other devices, if it could be successfully achieved One of the most challenging obstacles to MR valve development is the difficulty of achieving device miniaturization while, at the same time, improving the achievable performance This study demonstrates a novel design for an MR valve, using the meandering flow path approach in order to increase the effective area so that the MR fluid can be regulated within a small-sized valve The meandering flow path is formed by combining multiple annular, radial and orifice flow channels In order to analyze the valve performance, a mathematical model of the proposed MR valve is derived and combined with numerical simulation using the finite element method, with the intention of predicting the achievable pressure drop that can be generated by the valve The predicted MR valve performances are then experimentally evaluated using an oscillation-disturbed bypass hydraulic cylinder The simulation results show that the proposed MR valve design could yield substantial pressure drop improvement, which is confirmed by the experiment

Indonesian Men’s Perceptions of Violence Against Women

Abstract: This article explores male perceptions and attitudes toward violence against women in Indonesia. It analyzes interview data from Indonesian men collected as part of a large multimethod Australian government-funded project on masculinities and violence in two Asian countries. Reluctance to talk about violence against women was evident, and the accounts of those men who did respond referred to three justificatory discourses: denial, blaming the victim, and exonerating the male perpetrator. The findings support continuation of government and nongovernmental organization (NGO) projects aimed at both empowering women and reeducating men.

Numerical study on pulverized biochar injection in blast furnace

Abstract: 1) Research and Education Center of Carbon Resources, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka, 816-8580 Japan. 2) Department of Mechanical Engineering, Graduate School of Engineering, Sebelas Maret University, Jl. Ir. Sutami 36 A Surakarta, 57126 Indonesia. 3) Department of Chemical Engineering, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395 Japan. 4) Department of Petroleum and Mining Engineering, Shahjalal University of Science & Technology, Sylhet, 3114, Bangladesh. 5) Department of Materials Process Engineering, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395 Japan.

Exact solution of Dirac equation for Scarf potential with new tensor coupling potential for spin and pseudospin symmetries using Romanovski polynomials

Abstract: The bound state solutions of Dirac equations for a trigonometric Scarf potential with a new tensor potential under spin and pseudospin symmetry limits are investigated using Romanovski polynomials. The proposed new tensor potential is inspired by superpotential form in supersymmetric (SUSY) quantum mechanics. The Dirac equations with trigonometric Scarf potential coupled by a new tensor potential for the pseudospin and spin symmetries reduce to Schrodinger-type equations with a shape invariant potential since the proposed new tensor potential is similar to the superpotential of trigonometric Scarf potential. The relativistic wave functions are exactly obtained in terms of Romanovski polynomials and the relativistic energy equations are also exactly obtained in the approximation scheme of centrifugal term. The new tensor potential removes the degeneracies both for pseudospin and spin symmetries.

Cooperative inventory model for vendor-buyer system with unequal-sized shipment, defective items and carbon emission cost

Abstract: We develop an integrated inventory model for single-vendor single-buyer with deterministic demand. The vendor’s production process may be deteriorated during production run and results to some defective items. The defective probability is assumed to be uniformly distributed. The shipment from vendor to buyer is made in unequal size over multiple shipments. We also incorporate the carbon emission cost and investigate the environmental impact on the model. The results of the study show that adopting unequal-sized shipment policy in the model which considering defective items will result in lower carbon emission cost and total cost compared to an equal-sized policy. Furthermore, the increase in defective probability will lead to the increase of carbon emission cost.

Visible light photoelectrocatalytic degradation of rhodamine B using a dye-sensitised TiO2 electrode

Abstract: Titanium dioxide is a promising catalyst for application in the photodegradation of organic pollutants in water due to its powerful oxidising property and long-term photostability. This study presents the production of titanium dioxide using the sol-gel process, dye sensitisation of the TiO2 electrode, and the performance of that cell. Sensitisation of titanium dioxide was performed using a dye, i.e., Fe(II)-polypyridyl complexes. The photoelectrocatalytic degradation of rhodamine B (RB) using ITO/TiO2/dye as electrode was investigated via a series of potentials, from +1.0 V to −1.0 V, and at various pH and NaCl concentration values (ITO is indium tin oxide conductive glass). The photoelectrocatalytic degradation of RB was performed with a visible light lamp. The change in the absorbance of RB with various potentials indicated that the absorbance of RB in solution systems with the sensitised TiO2 electrodes decreased with increasing anodic potential bias. The degradation cell exhibited better performance when the positive anodic bias was applied. The pH values of RB in solution systems also influence the photoelectrodegradation process because of the different RB species present. NaCl concentration also affects the activity of RB photoelectrocatalytic degradation due to changes in the ionic strength character of the electrolyte.

Penerapan Model Problem Based Learning (Pbl) Pada Pembelajaran Hukum - Hukum Dasar Kimia Ditinjau Dari Aktivitas Dan Hasil Belajar Siswa Kelas X IPA SMA Negeri 2 Surakarta Tahun Pelajaran 2013/2014

Abstract: Telah dilakukan penelitian yang bertujuan untuk mengetahui aktivitas belajar ( visual, oral, writing, listening, mental, dan emotional ) dan hasil belajar (sikap, keterampilan, dan pengetahuan) siswa pada materi hukum-hukum dasar kimia dengan menerapkan model pembelajaran PBL yang dilengkapi LKS pada pelaksanaan Kurikulum 2013. Penelitian ini merupakan penelitian deskriptif kualitatif yang terdiri atas tahap orientasi, eksplorasi, dan member check . Subyek penelitian diambil dengan teknik purposive sampling yaitu siswa kelas X IPA 3 SMA Negeri 2 Surakarta tahun pelajaran 2013/2014 yang berjumlah 32 siswa. Sumber data berasal dari guru dan siswa. Data penelitian dikumpulkan melalui metode wawancara, observasi, angket, dokumentasi/arsip, dan tes. Teknik pengumpulan data dilakukan dengan tes (ranah pengetahuan) dan non tes (angket sikap dan aktivitas belajar). Berdasarkan hasil penelitian menunjukkan bahwa: 1) Proses belajar yang ditinjau dari aktivitas siswa ( visual, oral, writing, listening, mental, dan emotional ) dengan model PBL dilengkapi dengan LKS dalam penerapan kurikulum 2013 dikategorikan baik dengan dengan rata-rata 82,71 dan persentase ketercapaian sebesar 81,25%, 2) Hasil belajar siswa pada ranah pengetahuan, sikap, dan keterampilan siswa dengan model PBL dilengkapi dengan LKS dalam penerapan kurikulum 2013 dikategorikan baik dengan rata-rata nilai berturut-turut adalah 81; 83; dan 79, dan 3) Hasil belajar siswa pada ranah pengetahuan, sikap, dan keterampilan siswa dengan model PBL dilengkapi dengan LKS dikategorikan baik dengan persentase siswa yang mencapai kompetensi inti kurikulum 2013 berturut-turut adalah 78%, 81,24% dan 78,13%. Kata Kunci : deskriptif kualitatif, problem based learning (PBL), aktivitas belajar, hasil belajar

Social responsibility reporting of Islamic banks: evidence from Indonesia

Abstract: There is a growing global interest in social responsibility and sustainability across all sectors. Other than economic performance, stakeholders are now also concerned about the social and environmental impacts of corporations. Additionally, stakeholders are obtaining a higher salience level and expect organisations to operate sustainably. The banking sector has not been an exception, as banks can have significant impact on their customers, employees, and society in various ways. Given the intertwined links of Islam and ethical principles, it is expected that Islamic banks will show a high level of commitment towards social responsibility (SR) and ethical practices. The current study investigates this issue by examining the annual reports of three fully-fledged Islamic commercial banks in Indonesia over the period of 2007 to 2011. It was found that only two of the investigated banks had continuous improvement in their SR disclosure. Additionally, it was revealed that the highest disclosures have been for ‘corporate vision’ and ‘board of directors and top management’, while the lowest disclosures were evident for ‘environment’ and ‘product, services and fair dealing with supply chain’.

Optimization Parameters and Synthesis of Fluorine Doped Tin Oxide for Dye-Sensitized Solar Cells

Abstract: Transparent conductive oxide (TCO) is one of the important components in dye-sensitized solar cells. The main requirements of TCO for dye-sensitized solar cells are having a low electrical resistance and a high light transmittance. This study focuses on the synthesis of fluorine-doped tin oxide including its optimization. The synthesis of fluorine-doped tin oxide has been conducted under spray pyrolysis technique in which a precursor solution of SnCl2:F having concentration of 0.3, 0.5, 0.7, and 0.9 M. The spray pyrolysis was performed using a nebulizer with deposition time of 10 min. The glass substrate was heated at a temperature of 400, 450, and 500°C prior to deposition. The fluorine doped tin oxide was then measured the electrical resistivity for each area of ​​1 cm². Therefore, the mean and distribution of electrical resistivity of fluorine-doped tin oxide with an area of ​​10 x 10 cm then were predicted. In addition, the morphology and transmittance of fluorine-doped tin oxide are also examined. The optimization of the synthesis process of fluorine-doped tin oxide using spray pyrolysis was obtained at a concentration of 0.7 M with a sintering temperature of 400°C. The best fluorine-doped tin oxide has been also fabricated into the dye-sensitized solar cell and the performance has been studied.

Polypropylene/organoclay nanocomposites prepared using a Laboratory Mixing Extruder (LME): crystallization, thermal stability and dynamic mechanical properties

Abstract: Nanocomposites based on polypropylene and surface modified nanoclay (organoclay) masterbatch were prepared via melt blending using a Laboratory Mixing Extruder (LME). This work focused on the study of crystallization, thermal stability and dynamic mechanical properties of the nanocomposites. The effect of organoclay content (5, 10, and 15 wt.%) on non-isothermal and isothermal crystallization of the nanocomposites was studied by Differential Scanning Calorimetry (DSC). Thermal stability and dynamic mechanical properties of the nanocomposites were investigated by Thermogravimetric Analysis (TGA) and Dynamic Mechanical Analysis (DMA), respectively. The DSC results showed that the organoclay played an important role in the crystallization of nanocomposites by acting as “nucleating agent” (heterogeneous nucleation). It was confirmed by the appearance of second crystallization peak, which was attributed to crystallization process induced by heterogeneous nucleation of organoclay. There were also a crystallization temperature shift, a reduction in half-time crystallization (t 1/2), and an increase of crystallization kinetic constants of the nanocomposites. The TGA results showed that the addition of organoclay significantly increased the thermal stability of PP matrix, which was likely due to the characteristic and labyrinth effect of layered silicates/clays dispersed in PP matrix, and also the formation of multilayered carbonaceous–silicate char. A well-known Coats-Redfern method was used to evaluate the kinetic of thermal decomposition. Additionally, the stiffness characteristic of organoclay also greatly improved the dynamic mechanical properties (i.e. storage modulus, G′) of the nanocomposites. The DMA results demonstrated that the resistance and durability of PP/organoclay nanocomposites against applied stress and thermal were higher than the PP matrix.

Multiwall carbon nanotubes filled polypropylene nanocomposites: Rheological and electrical properties

Abstract: Two types of commercial multiwall carbon nanotubes (MWCNTs), Baytubes® C70P and C150P were incorporated into polypropylene (PP) using melt blending technique that employs a twin screw extruder (TSE) to prepare the nanocomposites of two different concentrations (1 and 3 wt%). Subsequently, American Society for Testing and Materials (ASTM) standard samples were prepared with an injection molding machine. The prepared nanocomposites were characterized by their rheological and electrical properties using a rheometer and a picoammeter/voltage source, respectively. The effect of different types of MWCNTs and loading percentage in rheological and electrical properties was investigated in detail. The rheological analysis demonstrated a considerable dependence of the melt rheological properties of the PP/MWCNTs nanocomposites on the MWCNTs loading. The storage modulus (G′), loss modulus (G″) and complex viscosity |η*| increased with increasing MWCNTs loading. In addition, type C70P exhibited superior rheological properties compared to C150P. In terms of electrical properties, the addition of MWCNTs in the PP matrix decreased the volume resistivity of the matrix in a manner, proportional to the MWCNTs loading. No significant difference in volume resistivity was observed between the MWCNTs types. POLYM. ENG. SCI., 54:1134–1143, 2014. © 2013 Society of Plastics Engineers

Dampak erupsi gunung merapi terhadap lahan dan upaya-upaya pemulihannya

Abstract: The eruption of Merapi mountain has primary and secondary hazard and may damage to the land. In detail, the hazards are land degradation is a loss of some or many of germplasm and changes in plant biodiversity. The others hazard including loss of water catchment areas, the destruction of forests, and even the closing of the water source, as well as the loss of water channels. The burried of soil and soil formation inhibition were caused by the repeated eruptions of Merapi, beside the loss of roads access to agricultural land and loss of land ownerships boundaries by the eruption and cool lava. Materials of eruption are sand and pyroclastic materials, as well as the nature of cementation require special techniques and technology to use the land as new farmland. Land restoration efforts can be done with the land management by reforestation on government-owned land for water catchment function, agroforestry forage grass based, grazing field on land owned by the village and residents, with the use of organic materials in the eruption sandy soil ameliorant.

Pengembangan game edukasi kimia berbasis role playing game (rpg) pada materi struktur atom sebagai media pembelajaran mandiri untuk siswa kelas x sma di kabupaten purworejo

Abstract: Penelitian ini bertujuan untuk mengetahui: 1) kualitas game edukasi kimia berbasis Role Playing Game (RPG) berdasarkan penilaian ahli materi, ahli media, guru mata pelajaran kimia, dan uji coba terhadap siswa kelas X. 2) respon guru dan siswa terhadap game edukasi kimia berbasis Role Playing Game (RPG) sebagai media pembelajaran mandiri. Metode penelitian yang digunakan adalah metode penelitian dan pengembangan (Research and Development ) yang mengacu model pengembangan Borg and Gall. Kesimpulannya adalah game edukasi kimia berbasis Role Playing Game (RPG) yang dikembangkan memenuhi kriteria baik sebagai pembelajaran kimia mandiri. Ahli materi memberikan skor baik (80,00%), ahli media memberikan skor baik (82,40%), guru memberikan sangat baik (84,09%), siswa pada uji lapangan awal memberikan skor baik (82,44%), pada uji coba lapangan siswa memberikan skor baik (82,67%), dan pada uji pelaksanaan lapangan siswa memberikan skor sangat baik (84,97%). Pada penilaian respon terhadap media, guru memberikan skor sangat baik (91%), siswa dalam uji lapangan awal memberikan skor sangat baik (89,58%), pada uji coba lapangan siswa memberikan skor sangat baik (89,58%), dan pada uji pelaksanaan lapangan siswa memberikan skor sangat baik (90,13%). Adapun dari penilaian secara kualitatif yang berupa komentar dan saran, secara garis besar baik dari validator, guru, dan siswa mengatakan bahwa game edukasi kimia berbasis Role Playing Game (RPG) pada materi struktur atom untuk siswa SMA kelas X sudah dikatakan baik. Kata Kunci: pengembangan game edukasi kimia, role playing game, struktur atom

Stabilitas Antosianin Ekstrak Daun Jati (Tectona Grandis) terhadap Perlakuan pH dan Suhu

Abstract: Pemanfaatan bahan alam seperti daun jati sebagai pewarna makanan menjadi salah satu alternatif dalam mengurangi penggunaan pewarna sintetik. Daun jati mengandung pigmen antosianin yang dapat memberikan warna merah. Pemanfaatan daun jati sebagai pewarna makanan masih sedikit. Padahal banyak penelitian yang menyebutkan bahwa daun jati memiliki khasiat seperti antibakteri, antitoksik, dan antioksidan. Dalam pengolahannya, makanan sering kali melalui proses pemanasan dan perubahan pH, dimana kedua faktor tersebut akan mempengaruhi stabilitas antosianin. Penelitian ini bertujuan untuk mengetahui stabilitas ekstrak pigmen antosianin daun jati pada berbagai perlakuan pengolahan pangan meliputi pH (3, 5, 7), dan suhu (750C, 1000C, 1210C) ditinjau dari total antosianin, aktivitas antioksidan, dan kualitas warna. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) yang terdiri dari satu faktor dengan perlakuan pH dan suhu. Data hasil analisis pada penelitian ini diuji secara statistik menggunakan sidik ragam ANOVA dengan SPSS. Jika terdapat perbedaan maka dilanjutkan dengan Duncan Mulitiple Range Test (DMRT) pada α = 0,05. Hasil penelitian yang diperoleh menunjukkan bahwa adanya perlakuan pH dan suhu mempengaruhi stabilitas ekstrak daun jati. Semakin tinggi nilai pH dan suhu, stabilitas ekstrak (ditinjau dari kadar total antosianin, aktivitas antioksidan dan kualitas warna) semakin menurun. Perlakuan yang paling menjaga stabilitas pigmen antosianin ekstrak daun jati adalah perlakuan pH 3 dan suhu 75 0C.

Semantic mapping relational to graph model

Abstract: Making data to be more connected is one of the goals of Semantic Technology. Therefore, relational data model as one of important data resource type, is needed to be mapped and converted to graph model. In this paper we focus in mapping and converting without semantically loss, by considering semantic abstraction of the real world, which has been ignored in some previous researches. As a graph schema model, it can be implemented in graph database or linked data in RDF/OWL format. This approach studies that relationship should be paid more attention in mapping and converting because, often be found a gap semantic abstraction during those processes. In our small experiment shows that our idea can map and convert relational model to graph model without semantically loss.

The Equivalence of Translated Songs Lyrics and their Effects - The Case of Translated Ecclesial Songs

Abstract: This study aimed at describing the equivalence of eclessial song lyrics, which belong to the content word, the meaning of the sentences and their effect on church songs. The method used in this study is descriptive and qualitative by using music, language, and interdiciline approach. The data collection method used questionnaires technique, interview, documents and content analysis. The data used are 5 documents of songs chosen purposively as the primary data. Based on the data being analyzed, the results of this study were: 1) The translated content word located in the same bars and equivalent was around 27.07%, the translated content word located in the same bars, but not equivalent was 18.34%, the translated content word located in the different bars, but equivalent was 11.79%, the translated content word located in the different bars and not equivalent was 2.62%, and the untranslated words were 4.17%. 2) The translation of equivalence beautiful lyrics showed the beauty of the song was equivalent at 17.02%, the beauty of the song was less equivalent at 29.78%, the beauty of the song was not equivalent of 61.70%. 3). The differences of structure caused the incorrect dictions or choice of words and missing words in the translated lyrics.

Effect of the Bucket and Nozzle Dimension on the Performance of a Pelton Water Turbine

Abstract: Pelton turbine is an engine that facilitates continuous power as a wheel or a rotor continually turns due to the pressure of fast moving water through the bucket, where a bucket receives water from the surging nozzle. The objective of this research is to investigate the highest efficiency among different types of Pelton turbine through the modification of bucket volume, bucket angle attack, nozzle needle seat ring, and nozzle needle tip. The experiment was conducted at Energy Conversion Laboratory of Sebelas Maret University. The comparative study among the different parameters shows that the value of maximum efficiency was 21.65%, which was obtained at 90° needle seat ring and 45° needle tip, and +15% bucket size and 92° angle of attack. It was gained likely due to the lightness of the +15% bucket compared to the standard bucket and the collision produced by the jet water in the middle of the bucket, in which the water loading occupied the large area on the surface of the bucket and promoted the increasing speed. It is expected that the result on the appropriate size and angle attack of bucket at specific nozzle seat ring and nozzle tip of this experiment can be manufactured commercially in the future for achieving maximum Pelton turbine efficiency.

Visible Light Photoelectrocatalytic Degradation of Rhodamine B Using Ti/TiO2-NiO Photoanode

Abstract: The method of Ti/TiO2-NiO photoelectrode prepared by using sol-gel method continued by calcination process was introduced. The prepared TiO2-NiO film was observed with XRD and TEM. The anatase-rutile TiO2 was mainly on the prepared TiO2-NiO composite surface electrode. In addition to NiO, the composite also formed NiTiO3 that increased with increasing calcination temperature. Photoelectrocatalytic degradation of Rhodamine B (RB) using this electrode was investigated, and anodic potential and pH were optimized. RB degradation was investigated under different conditions, and it showed that photoelectrocatalytic degradation could achieve efficient and complete mineralization of organic pollutant. Through comparison of the photoelectrocatalytic oxidation using the Ti/TiO2-NiO electrode operated by single photoanode with the Ti/TiO2-NiO electrode operated by several photoanode, it was found that the photoelectrocatalytic efficiency of that by series photoanodes was higher. Additionally, photoelectrocatalytic system was performed at the several different photoelectrodes, which verified the higher photocatalytic activity compared with the single photoelectrode.

The Persuasive Utterances in a Political Discourse (The Case Study of the Regent Election Campaign of Pasuruan, East Java-Indonesia)

Abstract: This article describes the result of the research study of persuasive utterances used by the campaign speakers of the Regent and vice Regent election at Pasuruan, East Java. The specific aim of the study is to describe the patterns, strategies and culture-social norms of persuasive utterances used in the political campaign based on the pragmatic perspective. Theoretically, persuasive utterances are defined as the ones to influence and convince the hearers to do the acts wanted by the speakers. Therefore, the utterance types can be categorized into 'directive-speech acts'. Having been pragmatically studied, however, the persuasive utterances which have been functioned as 'directive-speech acts', are not merely used in 'directives' but also in other speech-acts such as: assertive/representatives, commissives, expressives, and declaration. That's why, they can be classified into 'directives' in the form of direct utterances and 'directives' in the form of indirect utterances. Then, in this study direct utterances are categorized into 'directives' while indirect utterances are categorized into combination forms such as: assertive-directives, commissive-directives, expressive-directives, and declaration-directives. Besides reflecting the patterns, these speech-acts also reflected the strategies of utterances in which the norms of culture and social life of the local people can be described. These norms can be identified based on the utterance forms and strategies that the speakers used and also the attitudes or social behaviors that they showed, such as: politeness, the harmony of the team work, and their obedience to kiai or ulama (Moslem scholars) in determining their political wisdom. Thus, the persuasive utterances and persuasive acts produced by the speakers can be said to have an impact to the norms of positive and negative politeness of speakers and hearers.Keywords: Pragmatic study, Persuasive utterances, Directive speech-acts, Strategies of utterances, Political campaign, Norms of social life1. IntroductionThe back ground of the study is based on the impoliteness of political campaign events held by the political parties by the time of the General Election of the House of Representatives and the Head of Government (President, Governor, Regent and Mayor). The problems above were mostly seen from the deviation of campaign regulations or campaign ethics, such as distributing the media of campaign (the pictures of candidates) broadly before the time of campaign came.Referring to the background of the study, this research is categorized as "qualitative' in the form of "ethnography'. Related to the research design mentioned above, then the aims of the study are focused on the descriptions of the utterance patterns, strategies, and norms of culture and social life which were produced by each utterance such as: the politeness of utterances, the politeness of persuasive acts, and political culture behaved by the persuaders.To achieve the goal of the study, then the researcher analyzed 151 utterances of the total number of 460 utterances which were available in a data corpus. Those utterances were analyzed using techniques and approaches of the following dimensions: (1) dimension of pragmatic theories, (2) dimension of persuasion theories, and (3) dimension of social and culture theories.1.1 Dimension of Pragmatic Theories.Theoretically, this study cannot be separated from pragmatic theories argued by the linguists, such as Austin, the Britain linguist (1962) who argued the earliest speech-act theory. This theory was adopted from Malinowski's views (1923) which show that each utterance made by a speaker is an act. In this case, Malinowski argued that language was not only used as a means of saying the words but also doing the acts. Even, in a phatic communication, what a speaker says also produces an act. The other linguists who developed Malinowski's theory are Jacobson (1960), Searle (1969), and Kreidler (1998). …

Penerapan peer tutoring dilengkapi animasi macromedia flash dan handout untuk meningkatkan motivasi berprestasi dan prestasi belajar siswa kelas xi ipa 4 sman 6 surakarta tahun pelajaran 2013/2014 pada materi kelarutan dan hasil kali kelarutan

Abstract: Tujuan penelitian ini adalah untuk meningkatkan motivasi berprestasi dan prestasi belajar siswa kelas XI IPA 4 semester genap SMA Negeri 6 Surakarta tahun pelajaran 2013/2014 pada materi pokok Kelarutan dan Hasil Kali Kelarutan dengan penerapan pembelajaran Peer Tutoring dilengkapi animasi Macromedia Flash dan Handout . Penelitian ini merupakan Penelitian Tindakan Kelas ( Classroom Action Research ) yang dilaksanakan dalam dua siklus, dengan tiap siklus terdiri atas perencanaan, pelaksanaan, observasi dan refleksi. Subjek penelitian adalah siswa kelas XI IPA 4 SMA Negeri 6 Surakarta Tahun Pelajaran 2013/2014 yang berjumlah 24 siswa. Sumber data berasal dari guru dan siswa. Teknik pengumpulan data adalah dengan tes dan nontes (observasi, kajian dokumen dan angket). Analisis data menggunakan teknik analisis deskriptif kualitatif. Hasil penelitian menunjukan bahwa pembelajaran peer tutoring dilengkapi animasi macromedia flash dan handout dapat meningkatkan: (1) motivasi berprestasi siswa kelas XI IPA 4 SMA Negeri 6 Surakarta Tahun Pelajaran 2013/2014 pada materi kelarutan dan hasil kali kelarutan, pada siklus I diperoleh persentase pencapain motivasi berprestasi siswa sebesar 67% meningkat menjadi 92% pada siklus II (2) prestasi belajar dalam aspek kognitif maupun afektif siswa kelas XI IPA 4 SMA Negeri 6 Surakarta Tahun Pelajaran 2013/2014 pada materi kelarutan dan hasil kali kelarutan. Pada siklus I ketuntasan belajar siswa 58%, sedangkan pada siklus II mencapai 83%. Untuk aspek afektif pada siklus I persentase pencapaiannya sebesar 71% dan meningkat menjadi 100% pada siklus II.

Effect of Natural and Synthetic Dyes on the Performance of Dye-Sensitized Solar Cells Based on ZnO Nanorods Semiconductor

Abstract: The compatibility between natural dyes and semiconductors to produce a good performance of dye-sensitized solar cells plays an important role. The dyes from papaya leaves, mangosteen pericarps, beetroots, and N719 were investigated as sensitizers in the ZnO nanorods-based dye-sensitized solar cells. The ZnO film-coated fluorine-doped tin oxide glass substrates were prepared using a doctor blade method, followed by sintering at 450 °C. Meanwhile, the counter electrode contained of chemically deposited catalytic platinum coating. The working electrodes were first immersed in the N719 dye solution and the respective natural dye solutions at corresponding concentrations of 8 g/100 mL and 21 g/100 mL. The absorptance spectra of the dyes and dye-loaded semiconductor-working electrode were obtained by UV-Vis spectroscopy. In addition, the Fourier transform infrared spectroscopy was used to determine the characteristic functionalities of the dye molecules. Furthermore, N719-based DSSC displayed the highest efficiency (0.47%) whereas papaya leaf-based DSSC achieved the highest efficiency (0.17%) amongst the studied natural dye-based DSSCs. The improved efficiency noted in the natural dye-based DSSC was attributed to the increased current density value. The high absorptance and low electrical resistance of the DSSC loaded with papaya leaf-based dye (concentration: 8 g/100 mL) contributed to the high generated current density value. However, further studies are required to improve the fill factor properties of these solar cells that were < 33%.

Joint economic lot size (JELS) model for single-vendor single-buyer with variable production rate and partial backorder

Abstract: This paper presents joint economic lot size (JELS) models under stochastic demand for single-vendor single-buyer system by synchronising ordering, production and raw material procurement cycles. We consider variable production rate and partial backorder in the proposed model. An iterative procedure is employed to determine simultaneously safety factor, delivery lot size, delivery frequency, production batch, raw material lot size and production rate for minimising total cost. We investigate the behaviour of the model with the use of numerical analysis. Our study indicates that considering variable production rate in the model results in lower total cost compared to the case where the production rate is assumed to be fixed. Our study also shows that the increase in demand uncertainty leads to higher total costs, but the buyer absorbed most of the increase. In addition, we also show that the minimum total cost is obtained when the shortages are fully, rather than partially, backordered.

Pengembangan Instrumen Penilaian Two-Tier Multiple Choice Untuk Mengukur Keterampilan Berpikir Tingkat Tinggi (Higher Order Thinking Skills) Pada Materi Kelarutan Dan Hasil Kali Kelarutan Untuk Siswa Sma/Ma Kelas Xi

Abstract: Penelitian ini bertujuan untuk mengembangkan instrumen penilaian Two-tier Multiple Choice yang memiliki validitas, reliabilitas, tingkat kesukaran, daya pembeda dan indeks pengecoh yang memenuhi kriteria sebagai suatu soal yang baik dan mengembangkan instrumen Two-tier Multiple Choice pada materi kelarutan dan hasil kali kelarutan menjadi instrumen penilaian yang mampu mengukur keterampilan berpikir tingkat tinggi.Penelitian ini merupakan penelitian pengembangan yang terdiri dari analisis kebutuhan dan penelitian awal, perencanaan, pengembangan bentuk awal produk, revisi dan uji lapangan awal, revisi dan uji lapangan utama, dan revisi dan uji pelaksanaan lapangan. Subjek penelitian pada penelitian ini adalah siswa kelas XI IPA SMAN 1 Surakarta dan SMAN Sragen Bilingual Boarding School tahun ajaran 2013/2014. Data penelitian diperoleh melalui wawancara, tes dan angket.Berdasarkan hasil penelitian yang telah dilakukan kesimpulan yang didapatkan adalah instrumen penilaian Two-tier Multiple Choice yang dikembangkan dinyatakan layak dan memenuhi kriteria sebagai suatu soal yang baik dengan hasil validitas isi (CV) 1,00, memiliki reliabilitas tes rata-rata 0,92 yang tergolong sangat tinggi, memiliki tingkat kesukaran dengan persentase 4,1% (mudah), 79,2% (sedang), dan 16,7% (sukar), memiliki daya pembeda dengan persentase 18,7% (sangat baik), 39,6% (baik), 14,6% (cukup), 27,1% (jelek), dan memiliki indeks pengecoh dengan persentase 26,1% (sangat baik), 21,9% (baik), 30,2% (kurang), 18,2% (buruk), dan 3,6% (sangat buruk) dan instrumen Two-tier Multiple Choice untuk mengukur keterampilan berpikir tingkat tinggi pada materi kelarutan dan hasil kali kelarutan yang dikembangkan cukup mampu mengukur keterampilan berpikir tingkat tinggi dengan angka konsistensi 41,6%. Kata Kunci : Penelitian dan pengembangan (R&D), Two-tier multiple choice, Higher order thinking skills, kelarutan dan hasil kali kelarutan

High-efficiency plasma surface modification of graphite-encapsulated magnetic nanoparticles using a pulsed particle explosion technique

Abstract: A high-efficiency surface modification of graphite-encapsulated iron compounds magnetic nanoparticles using an inductively coupled radio-frequency plasma with a pulsed particle explosion technique was studied. A significant increase in N 1s peak intensity in the X-ray photoelectron spectroscopy spectra was obtained by applying a negative pulsed bias voltage of ?1 kV to the substrate stage for 15 s or less at a repetition frequency of 1 kHz and a duty ratio of 50% in ammonia plasma. The intensity of the N 1s peak and the N/C ratio of the nanoparticles treated in a pulsed particle explosion system were 3?4 times higher than those of the particles treated without bias. The amino group population of nanoparticles treated using the present technique was determined to be about 8.2 ? 104 molecules per nanoparticle, roughly four times higher than that of particles treated without bias. The dispersion of the plasma-treated nanoparticles was significantly improved compared with those of the untreated and treated particles in the nonbiasing system. The surface structure analysis by transmission electron microscopy showed no significant damage on the structure or morphology of the treated nanoparticles, indicating that the present technique is applicable to the high-efficiency surface modification of magnetic nanoparticles.