IDENTIFIKASI DAN UPAYA YANG DILAKUKAN GURU DALAM MENGATASI HAMBATAN PELAKSANAAN PEMBELAJARAN RNIPS TERPADU DI MTSN MODEL BANDA ACEH

ABSTRAKKata Kunci: identifikasi, hambatan, pembelajaran, IPS terpaduPembelajaran IPS terpadu merupakan gabungan antara berbagai disiplin ilmu sosial, yang biasanya terdiri atas beberapa mata pelajaran seperti geografi, sosiologi, ekonomi, dan sejarah, maka dalam pelaksanaannya tidak lagi terpisah-pisah melainkan menjadi satu kesatuan. Kurangnya keefektifan guru dalam proses pembelajaran IPS terpadu yang meliputi beberapa disiplin ilmu dengan menggunakan guru tunggal, hal tersebut dikarenakan guru mengajar semua mata pelajaran yang terdapat dalam pembelajaran IPS terpadu. Penelitian ini mengangkat masalah apakah hambatan guru dalam pelaksanaan pembelajaran IPS terpadu di MTsN Model Banda Aceh dan upaya apa yang dilakukan guru untuk mengatasi hambatan pelaksanaan pembelajaran IPS terpadu di MTsN Model Banda Aceh. Tujuan penelitian adalah untuk mengidentifikasi hambatan dalam pelaksanaan pembelajaran IPS terpadu dan untuk mengetahui upaya apa yang dilakukan guru dalam mengatasi hambatan pelaksanaan pembelajaran IPS terpadu di MTsN Model Banda Aceh. Informan dalam penelitian adalah guru IPS terpadu yang berjumlah enam orang. Metode yang digunakan dalam penelitian adalah deskriptif kualitatif, data diperoleh dengan cara wawancara mendalam. Teknik analisis data menekankan penjelasan serta penguraian data melalui cerita tentang peristiwa yang telah diteliti. Hasil analisis data menunjukkan bahwa terdapat kendala yang dialami guru dalam pembelajaran IPS terpadu di MTsN Model Banda Aceh yaitu penguasaan materi, kurangnya waktu bertatap muka dalam pembelajaran, dan kurangnya minat belajar siswa terhadap mata pelajaran IPS. Upaya yang dilakukan guru bidang studi IPS terpadu untuk mengatasi masalah tersebut adalah lebih banyak membaca atau menambah referensi untuk bahan ajar, mencari bahan di internet dan sharing sesama guru mata pelajaran, penggunaan waktu seefektif mungkin, dan memberikan motivasi kepada siswa pada saat pembelajaran berlangsung yaitu dengan menerapkan berbagai macam model pembelajaran.Banda Ace

Oxygen permeability and improved stability of a permeable Zr-substituted perovskite membrane for air separation

Abstract Zr-substituted Ba 0.5 Sr 0.5 Co 0.8 Fe 0.1 Zr 0.1 O 3−δ (BSCFZO) powders for oxygen membrane were synthesized by the solid-state reaction (SSR) method. Oxygen permeation fluxes (J O 2 ) across the dense Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3−δ (BSCFO) and BSCFZO membrane disks were measured at 973-1123 K, and they increased as BSCFO (synthesized by improved EDTA-citric acid complexing method, ECC) > BSCFO (SSR) > BSCFZO. The reduced oxygen permeability of Zr-substituting BSCFZO material can be attributed primarily to the higher oxidation state of Zr cations than ones of iron cations, thus lead to the decrease in the oxygen vacancy concentration in BSCFO. Oxygen permeation measurements with different oxygen partial pressure gradients and membrane thicknesses demonstrate the bulk oxide ionic diffusion is the rate-limiting step for the BSCFZO membrane in the range of temperatures investigated (973-1123 K). The enhanced stability of BSCFZO demonstrated by the differential thermal analysis (DTA) and high-temperature X-ray diffraction (HT-XRD) characterizations, show that the structural stability can be improved when the Fe ions in the B-sites of BSCFO materials are substituted partially by Zr cations

The impact of different sentiment in investment decisions: evidence from China’s stock markets IPOs

In this study, we used data on China’s initial public offerings (IPOs), market volatility and macro environment before and after two stock crashes during 2006–2016 to investigate how different investor sentiment affects IPO first-day flipping. The empirical results show that the expected returns of allocated investors are affected by sentiment, with allocated investors having higher psychological expectations of future returns during an optimistic bull market and their optimism discouraging first-day flipping, while higher risk-free interest rate levels and rising broad market indices also discourage first-day flipping and tend to sell in the future. The pessimistic bear market during which allocated investors have lower psychological expectations of future returns, their pessimism will promote first-day flipping, and the increase in the risk-free rate level will also promote first-day flipping, which is the opposite of the optimistic bull market, indicating that their risk aversion has increased and they tend to sell on the same day. We also found an anomaly that the greater the decline in the broad market index during a pessimistic bear market, the more inclined the allocated investors are to sell in the future when the broad market index rises in an attempt to gain higher returns. These findings help explain and understand the impact of market and macro index fluctuations on investor behavior under different investor sentiments

Oxygen diffusion in oxide crystals - tracing new routes to identify the rate limiting step of oxygen permeation through perovskite membranes: Oxygen diffusion in oxide crystals - tracing new routes to identifythe rate limiting step of oxygen permeation through perovskitemembranes

Perovskites are known as mixed electric conductors because they show both electronic (via electron holes) and ionic (via oxygen vacancies) conductivity. Since the electron conductivity is orders of magnitude higher than the ionic one, oxygen vacancy bulk diffusion is regarded as the rate limiting step in oxygen permeation through perovskites. However, for thin perovskite layer the rate of this bulk diffusion process starts to compete with the so called surface reaction which represents the dissociative adand desorption of the oxygen molecule and the incorporation/release of the oxygen ions from the perovskite framework. The oxygen permeation flux through the perovskite membrane made of Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ (BSCF) has been measured as a function of both the temperature, membrane thickness and the oxygen pressure gradient across the membrane. A combined bulk diffusion/surface reaction model can be used to understand the mechanism of the oxygen transport. The limiting step of the oxygen transport was found to be the bulk oxygen ion diffusion coefficient (D i ) for the BSCF perovskite at temperatures above 700 ℃. Furthermore, the oxygen vacancy diffusion coefficient (D v) can be deduced from the dependence of the oxygen permeation flux on the oxygen pressure gradient provided that the oxygen vacancy δ are known. From permeation measurement on the BSCF membrane tube under study, is found to be between 2.82×10 -5 cm2/s at 900 ℃ and 0.82×10 -5 cm2/s at 700 ℃

One-pot synthesis of NiAl-CO3 LDH anti-corrosion coatings from CO2-saturated precursors

Anti-corrosive coatings based on layered double hydroxides (LDHs) have been considered as promising alternatives to conventional chromate-containing conversion coatings. Among various LDHs, carbonate-intercalated LDH coatings with a c-axis preferred orientation should be the optimum structure for protecting metals against corrosion. Herein we successfully prepared NiAl–CO3 LDH coatings on aluminium plates in one step. Particularly it was found that CO2 dissolved in the precursor solution exerted great influence on the microstructure and anti-corrosion capacity of prepared LDH coatings. Trace amounts of CO2 in the precursor solution led to the formation of ab-oriented 7 μm-thick LDH coatings, while preferentially c-oriented LDH coatings with an average thickness of 12 μm were formed from CO2-saturated precursor solutions. A DC polarization test demonstrated that preferentially c-oriented LDH coatings exhibited much higher anti-corrosion performance than ab-oriented LDH coatings possibly due to the decreased density of mesoscopic defects. Simultaneously, CO2, the green gas, was also positively utilized.Alexander von Humboldt FoundationNatural Science Foundation of China/21176231Natural Science Foundation of China/21361130018Natural Science Foundation of China/ 21476223CAS 100-talent programGZ 911/Sino-German Cooperation Group on Inorganic Membrane

Improvement of hydrothermal stability of zeolitic imidazolate frameworks

The metal-organic framework ZIF-8, which undergoes hydrolysis under hydrothermal conditions, is endowed with high water-resistance after a shell-ligand-exchange-reaction. The stabilized ZIF-8 retains its structural characteristics with improved application performances in adsorption and membrane separation. © 2013 The Royal Society of Chemistry

Roadmap for Sustainable Mixed Ionic‐Electronic Conducting Membranes

Mixed ionic‐electronic conducting (MIEC) membranes have gained growing interest recently for various promising environmental and energy applications, such as H₂ and O₂ production, CO₂ reduction, O₂ and H₂ separation, CO₂ separation, membrane reactors for production of chemicals, cathode development for solid oxide fuel cells, solar‐driven evaporation and energy‐saving regeneration as well as electrolyzer cells for power‐to‐X technologies. The purpose of this roadmap, written by international specialists in their fields, is to present a snapshot of the state‐of‐the‐art, and provide opinions on the future challenges and opportunities in this complex multidisciplinary research field. As the fundamentals of using MIEC membranes for various applications become increasingly challenging tasks, particularly in view of the growing interdisciplinary nature of this field, a better understanding of the underlying physical and chemical processes is also crucial to enable the career advancement of the next generation of researchers. As an integrated and combined article, it is hoped that this roadmap, covering all these aspects, will be informative to support further progress in academics as well as in the industry‐oriented research toward commercialization of MIEC membranes for different applications

Microstructural Engineering and Architectural Design of Metal-Organic Framework Membranes

In the past decade, a huge development in rational design, synthesis, and application of molecular sieve membranes, which typically included zeolites, metal-organic frameworks (MOFs), and graphene oxides, has been witnessed. Owing to high flexibility in both pore apertures and functionality, MOFs in the form of membranes have offered unprecedented opportunities for energy-efficient gas separations. Reports on the fabrication of wellintergrown MOF membranes first appeared in 2009. Since then there has been tremendous growth in this area along with an exponential increase of MOF-membrane-related publications. In order to compete with other separation and purification technologies, like cryogenic distillation, pressure swing adsorption, and chemical absorption, separation performance (including permeability, selectivity, and long-term stability) of molecular sieve membranes must be further improved in an attempt to reach an economically attractive region. Therefore, microstructural engineering and architectural design of MOF membranes at mesoscopic and microscopic levels become indispensable. This review summarizes some intriguing research that may potentially contribute to large-scale applications of MOF membranes in the future

Microstructural and Interfacial Designs of Oxygen-Permeable Membranes for Oxygen Separation and Reaction-Separation Coupling

Mixed ionic-electronic conducting oxygen-permeable membranes can rapidly separate oxygen from air with 100% selectivity and low energy consumption. Combining reaction and separation in an oxygen-permeable membrane reactor significantly simplifies the technological scheme and reduces the process energy consumption. Recently, materials design and mechanism investigations have provided insight into the microstructural and interfacial effects. The microstructures of the membrane surfaces and bulk are closely related to the interfacial oxygen exchange kinetics and bulk diffusion kinetics. Therefore, the permeability and stability of oxygen-permeable membranes with a single-phase structure and a dual-phase structure can be adjusted through their microstructural and interfacial designs. Here, recent advances in the development of oxygen permeation models that provide a deep understanding of the microstructural and interfacial effects, and strategies to simultaneously improve the permeability and stability through microstructural and interfacial design are discussed in detail. Then, based on the developed high-performance membranes, highly effective membrane reactors for process intensification and new technology developments are highlighted. The new membrane reactors will trigger innovations in natural gas conversion, ammonia synthesis, and hydrogen-related clean energy technologies. Future opportunities and challenges in the development of oxygen-permeable membranes for oxygen separation and reaction-separation coupling are also explored