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This study aims to overcome some problems of students’ speaking ability at the Second Grade Students of Senior High School 6 Bengkulu Tengah, Bengkulu, Indonesia by using gallery walk technique. The participants of this study were 30 students. The method used in this study was Classroom Action Research (CAR). This study was carried out in two cycles. Each cycle consisted of four meetings. Each cycle consisted of four stages-planning, action, observing and reflecting. The result of this study showed that the students’ speaking ability was improved after the action was given to the students. Besides, using gallery walk technique could motivate the students to speak up confidently and also could make the students became more active and enjoy in learning process at the classroom. Most of the students gradually gained good scores at the end of the cycle. The minimum score of Mastery Criterion- Kriteria Ketuntasan Minimal (KKM) of English subject was 71 (seventy-one). In cycle I, the result of the students’ score was failed, where the mean score of the students was 70.29 (poor). However, in cycle II, the result of the cycle showed that there was good improvement. The students’ mean score in this stage was 80.83 (very good). In conclusion, gallery walk technique could improve students’ speaking ability.

The research aimed to examine the intention of Generation Z when using e-wallet for payments and the influence of discounts towards using e-wallet in the time of pandemics. The research used the qualitative method with total data of 22 students, collected using in-depth interviews through WhatsApp free call. The result shows that discount gives an impact on Generation Z in choosing the e-wallet, but a long-term loyalty is not guaranteed. The finding demonstrates that there are other influential factors for Generation Z to choose e-Wallet, namely ease of use, interrelated apps with the e-wallet, the security system, and cashless society. The limitations of the research lie in the relatively small numbers of respondents. Due to pandemics with physical distancing requirements, the research only carries out on data collected from 22 students from Economics Faculty in the State University of Malang, Indonesia. However, the research provides an insightful analysis for digital payments industry as a reference. It is expected that fellow researchers and academicians use the research as a fundamental to further investigate digital payments, especially amongst Generation Z in Indonesia or other parts of the world.

Phenolic compounds such as kaempferol (1), quercetin (2), and methyl caffeate (3) have been isolated from the ethyl acetate extract of Kalanchoe prolifera (Crassulaceae). The chemical structure of isolated compounds 1-3 were elucidated on the basis of spectroscopic evidence (UV, IR, NMR) and comparison with those compound previouly reported. DOI: http://dx.doi.org/10.15408/jkv.v0i0.5037

One effort to increase self-esteem (self esteem) students in school is through the optimization of cooperative learning with models collaborate fun-n-pick and team game tournament. Where both models support each other, but remain separate and not become a new model. The purpose of this study was to explain whether the implementation of cooperative learning collaborative model of Fun-n-pick and team games tournament can meningkatkatkan esteem (self esteem) in Class VI SDN Putat Kidul 01 District Gondanglegi and describe the obstacles faced and the support it receives in implementing collaboration models fun-n-pick and team game tournament. Through action research by using two cycles of research and sixth grade students of Putat Kidul 01 Elementary School District Gondanglegi by the number of students 30 people as the subject. The tools used to collect data in the form of documentation and questionnaires. Sources of data obtained directly from students by actions in the classroom. The results showed that the implementation of cooperative learning collaborative model of Fun-N-Pick and team games tournament can meningkatkatkan esteem (self esteem) students in the school, and outline the obstacles in this study is found in the first cycle, but these barriers can be overcome and make an endorsement in implementing collaborative model of fun-n-pick and team game tournament.

Various species of Kalanchoe plants have been widely used as raw materials in traditional medicines. This study was the continuation of the researches on secondary metabolites from Indonesia Kalanchoe plants, focused on Kalanchoe blossfeldiana. Fresh K. blossfeldiana leaf was extracted with methanol at room temperature to obtain the concentrated extract. The concentrated methanol extract was dissolved in water and then partitioned successively with n-hexane and ethyl acetate. The methanol, n-hexane, ethyl acetate extracts were tested using antiplasmodial assay against Plasmodium falciparum 3D7. The IC50 of methanol, n-hexane, and ethyl acetate extract were 13.002; 2.807, and 11 nM, respectively. Ethyl acetate extract was separated by the combination of chromatography on silica and ODS. This process produced the yellow solid. The chemical structure of the compound was determined based on UV, IR, MS, 1H-NMR, and 13C-NMR analyses and the comparison of data obtained from the literature and identified as phenolic compound, namely 3,3',4',5,7-pentahydroxyflavone or quercetin (1), and displayed antiplasmodial activity with IC50 3.97x10-2 nM.

Sintesis fotokatalis ZnO-Al untuk degradasi fenol dan reduksi Cd(II) secara simultan telah dilakukan. Tahapan penelitian meliputi sintesis, karakterisasi ZnO-Al dan uji aktivitas pada degradasi fenol. Metode yang digunakan untuk sintesis fotokatalis ZnO-Al adalah metode sol-gel spray coating dan metode yang digunakan untuk degradasi adalah metode fotokatalisis. Hasil karakterisasi fotokatalis ZnO-Al menggunakan XRD menghasilkan kristal dengan ukuran 15,07 nm dan karakterisasi menggunakan DRS UV-Vis menunjukkan celah pita (Eg) sebesar 2,58 eV. Penurunan konsentrasi dari fenol dan Cd(II) secara simultan adalah lebih besar pada penggunaan fotokatalis ZnO-Al baik menggunakan sinar UV-C dan sinar tungsteen daripada fotokatalis ZnO.

Abstract: This study aims to determine the economic value of shallot cultivation offseason and in-season. It was conducted in Srigading Village, Sanden District, Bantul Regency on March to July 2017 using comparative study method. Sampling was chosen purposively for village and farmer groups. Samples of farmers taken using proportional sampling and snowball sampling method by 30 peoples. Statistical analysis using the t-test. The results of the study showed that off-season and in-season shallot farming was not significantly different and feasible economically. This is can be seen from the result of t-test of average shallot farmers income is t-count0,05, the result of average difference test of farmers profit is t-count0,05, while the result of average difference test of business feasibility (R/C ratio) on shallotcultivation is t-count0,05. While analysis of farming is average revenue of shallot farmers off-season Rp 20.471.149,3 and in-season Rp 18.081.789,6, average profit of shallot farmers offseason Rp 11.922.949,9 and in-season Rp 10.520.079,9, and average business feasibility (R/C ratio) of shallot farmers off-season 2,39 and in-season 2,33. Abstrak: Kajian ini bertujuan untuk mengetahui nilai ekonomi budidaya bawang merah lahan pasir pantai off season dan in season. Kajian dilakukan di Desa Srigading Kecamatan Sanden Kabupaten Bantul bulan Maret-Juli 2017 dengan menggunakan metode kajian komparatif. Pengambilan sampel dipilih secara purposive untuk tingkat desa dan kelompok tani. Sampel petani diambil secara proporsional sampling dan snowball sampling sebanyak 30 orang. Analisis statistik menggunakan uji-t. Hasil kajian menunjukkan bahwa secara ekonomi usahatani bawang merah off season dan in season tidak berbeda nyata dan layak diusahakan. Hal ini dilihat dari hasil uji beda rata-rata penerimaan petani bawang merah yaitu t-hitung0,05,hasil uji beda rata-rata keuntungan petani bawang merah adalah t-hitung0,05, dan hasil uji beda rata-rata kelayakan usaha (R/C ratio) budidaya bawang merah yaitu t-hitung0,05. Sedangkan hasil analisis usahatani yaitu penerimaan rata-rata petani bawang merah off season Rp 20.471.149,3 dan in season Rp 18.081.789,6, keuntungan rata-rata petani bawang merah off season Rp 11.922.949,9 dan in season Rp 10.520.079,9, dan kelayakan usaha (R/C ratio) rata-rata petani bawang merah off season 2,39 dan in season 2,33.

Pemupukan merupakan salah satu faktor penting dalam budidaya tanaman. Tanaman ubi jalar diketahui sangat respon terhadap pemupukan. Penelitian ini telah dilaksanakan di lahan penelitian Politeknik Negeri Jember pada bulan April sampai Agustus 2017. Tujuan penelitian ini adalah mengetahui pengaruh dosis pupuk P dan K serta interaksinya terhadap laju pertumbuhan dan produksi tanaman ubi jalar varietas Antin 3. Rancangan percobaan yang digunakan adalah Rancangan Acak Kelompok faktorial dengan 3 kali ulangan. Faktor pertama dosis pupuk TSP (P) terdiri dari 3 taraf yaitu : P1 (78 kg/ha), P2 (117 kg/ha) dan P3 (157 kg/ha). Faktor kedua dosis pupuk KCL (K) terdiri dari 3 taraf yaitu : K1 (150 kg/ha), K2 (300 kg/ha) dan K3 (450 kg/ha). Data hasil penelitian dianalisis secara statistik menurut uji F dan uji lanjut DMRT. Faktor tunggal dosis P dan K serta interaksinya memberikan pengaruh yang tidak nyata terhadap parameter jumlah cabang. Faktor tunggal dosis P memberikan pengaruh nyata terhadap parameter laju pertumbuhan tanaman, jumlah umbi per tanaman, panjang umbi per tanaman dan bobot umbi total per tanaman. Perlakuan terbaik yaitu P3 dengan dosis TSP 157 kg/ha. Faktor tunggal dosis K memberikan pengaruh nyata terhadap parameter laju pertumbuhan, jumlah umbi per tanaman dan bobot umbi total per tanaman. Perlakuan terbaik yaitu K3 dengan dosis 450kg/ha. Interaksi dosis P dan K memberikan pengaruh nyata terhadap parameter bobot umbi total per bedeng. Perlakuan P3K3 yaitu dosis TSP 157 kg/ha + KCl 450 kg/ ha memberikan hasil tertinggi yaitu 7,2 kg/ bedeng

The objectives of this research were to determine: 1) Students’ learning activities in social studies after using Question Student Have (QSH) in Cooperative Learning Model, 2) Students’ learning outcomes in social studies after using Question Student Have (QSH) in Cooperative Learning Model. The method used in this research is Classroom Action Research (CAR) with Stephen Kemmis and Mc. Taggart Model which consists of four stages, namely planning, implementation, observation and reflection. This study was conducted by the researcher in two cycles. Instruments used in this research are observational sheet, interview, and test in the last cycle. From the analysis of the data, the researcher found that there is an improvement in students’ learning outcomes. On the basic value, there was only 43,33% students who achieve the learning mastery. In the first cycle, the students who achieve the learning mastery were increased, it was about 30% from the basic value, it reached 73,33%. On the second cycle, the student who achieve the learning mastery were increased about 26,70% from the first cycle, become 100%. The same thing also happened to the students' learning activities. In the first cycle, students’ learning activities is 71,42% and on the second cycle, students’ learning activities were incrased about 21,43% from the first cycle, become 92,85%. Based on the analysis of data of this study it can be concluded that the use of Question Student Have (QSH) in Cooperative Learning Model can improve students’ learning outcomes and learning activities fourth grade students of SDN Saga V in social studies. Keywords: social studies learning outcomes, cooperative learning QSH type.

Research problem is the first thing to be found by researcher. Then, he should limit it clearly so that it can be easy to be understood. At this step, the researcher needs special formula to write the problems statement in the form of research questions which the answers of them are the research goals. Writing good research question formulation will provide convenience for researchers in conducting research process. Thus, it is essential to give appropriate criteria in formulating research questions. This article describes some criteria for writing the formulation of research questions along with examples

MODEL ESTIMASI WABAH DEMAM BERDARAH DAN PENANGANAN KADER JUMANTIK DI WILAYAH MALANG RAYA (KOTA MALANG, KABUPATEN MALANG DAN KOTA BATU) Estimation Model of DHF Epidemic and It’s Handling of Jumantik Cadre at Malang Raya Region (Malang City, Malang District and Batu City) Moh. Hartono(1), Yoyok Heru P.I(2), Arif Rahman Hakim(3), Elief Yuniarti(4) (1,2,3)Politeknik Negeri Malang(4)Paramedis Puskesmas Dinoyo MalangEmail: 1)hartono@polinema.ac.id ABSTRAK Studi tentang wabah DBD telah banyak dilaksanakan akan tetapi penelitian yang mengkombinasikan peramalan dan analisis multivariat yang berkaitan dengan penanganan DBD masih jarang dijadikan kajian. Penelitian ini mencoba mengkombinasikan kedua metode diatas dalam menekan wabah DBD khususnya di wilayah Malang Raya (meliputi Kota Malang, Kabupaten Malang dan Kota Batu). Sejauh ini kelemahan penanganan dari wabah DBD adalah masih kurang tepatnya waktu antisipasi dan cara penanganan pencegahan wabah DBD. Hasil yang diperoleh dari penelitian ini berupa model waktu antisipasi yang tepat dan cara penanganan mencegah berjangkitnya wabah DBD. Model peramalan dalam bentuk ARIMA musiman ( p , d , q ) ( P , D , Q )12 dengan berbagai variasi di setiap wilayah. Sedangkan hasil dari analisis multivariat yang melibatkan analisis faktor adalah terbentuknya 10 faktor baru yang berpengaruh terhadap kinerja Kader Jumantik. Diharapkan dengan kombinasi kedua metode ini dapat menjadi masukan bagi Pemerintah lokal khususnya di wilayah Malang Raya dalam menangani wabah DBD. Kata Kunci: Peramalan, Analisis Faktor dan Model ARIMA. ABSTRACT The study of an epidemic of Dengue Hemorrhagic Fever ( DHF ) has been widely implemented , however, research on the combination of forecasting and factors analysis related to the handling of DHF is still small even rarely studied . This study tries to combine both methods in suppressing the development of dengue epidemic especially in Malang region which covers an area of Malang City, Malang District and Batu City . So far, Weakness of handling DHF is less precisely of anticipation timing and how to deal with dengue disease . The results of this study in the form of input anticipation appropiate time and the right way in preventing and combating dengue disease . Forecasting models in the form of seasonal ARIMA ( p , d , q ) ( P , D , Q )12 with diverse variations of each region . While the results of the factor analysis formed 10 new factors that affect the performance of its duties Jumantik cadres. Hopefully with this combination can be input for each Local Government in dealing with an epidemic of dengue fever Keywords: Forecasting, Factor Analysis, ARIMA Model

Penelitian ini bertujuan untuk mengetahui karaketristik biodiesel yang dihasilkan dari minyak goreng bekas menggunakan katalis H-Zeolit dan KOH. Biodiesel dibuat dengan mereaksikan minyak goreng bekas dan metanol dalam perbandingan 4:1 (volum) dan suhu 60 oC. Biodiesel yang dihasilkan dengan menggunakan katalis KOH mempunyai densitas 0,85 g/mL dan viskositas 3,09 cSt. Senyawa kimia yang dominan dalam biodiesel adalah metil heksadekanoat (29.90% area), 9-octadecenoic acid (Z)-metil ester (55.80% area). Sedangkan biodiesel yang menggunakan katalis H-zeolit mempunyai densitas 0,78 g/mL dan viskositas 0,35 cSt. Senyawa kimianya adalah metil heksadekanoat (10,85% area) dan 9-octanoic acid (Z)-metil ester (11,97% area). Biodiesel menggunakan katalis KOH memenuhi syarat kualitas biodiesel menurut SNI.

Using a simple drop-casting technique, we successfully fabricated a sensitive electrochemical sensor based on the composite of reduced graphene oxide (RGO) and multiwalled carbon nanotubes (MWCNT) deposited on the surface of a glassy carbon electrode (GCE) for individual and simultaneous measurements of hydroquinone (HQ), dopamine (DA), and uric acid (UA). The nanocomposite of RGO/MWCNT was further characterized in terms of its structural properties, surface morphology, and topography using Raman, FT-IR spectroscopy, SEM, HRTEM, and AFM. Then, the proposed sensor for simultaneous measurement of HQ, DA, and UA based on RGO/MWCNT-modified GCE was investigated for its electrochemical behavior and electroanalytical performances using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). In addition, the composition ratio between RGO and MWCT was 1 : 1 showing the highest electrochemical response for simultaneous detection of HQ, DA, and UA. Owing to the synergistic effect between RGO and MWCNT leading to excellent conductivity properties, the proposed sensor exhibited improved electrochemical response at pH 7 toward the oxidation processes of HQ, DA, and UA on the surface of modified electrode. The proposed sensor demonstrated three well-defined anodic peaks of these analytes with their linear concentrations ranges of 3.0-150.0 μM for HQ, 4.0-100.0 μM for DA, and 2.0-70.0 μM for UA. The limit of detection values for the simultaneous detection of HQ, DA, and UA were found as follows 0.400 ± 0.014, 0.500 ± 0.006, and 0.300 ± 0.016 μM, respectively. The additional features of this proposed sensor are high reproducibility and stability for the simultaneous detection of HQ, DA, and UA with negligible interference effect from interferents such as Mg 2+ , K + , Cl - , ascorbic acid, and glucose. An acceptable percentage of recovery was also shown by this sensor for simultaneous measurements of HQ, DA, and UA using 6 samples of human urine. In summary, the RGO/MWCNT nanocomposite has been shown to be a promising platform for rapid, simple, and reliable determination of simultaneous measurements of HQ, DA, and UA in practical applications., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Thermal conductivity and adhesion strength effects were studied for thermal barrier coatings (TBCs) with different particle sizes, YSZ content, time, and temperature curing. The study involves three stages. The first step focuses on the characteristics of YSZ/polysilazane as the TBC, which is characterized using Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), X-Ray Diffraction (XRD), and Thermal Gravimetric Analysis (TGA). The second and third steps assess thermal conductivity and adhesion strength based on variables such as particle size, YSZ/polysilazane, time, and curing temperature. Results show that there was a synergistic effect between particle size-YSZ content and time-temperature curing to obtain specimens with good thermal properties. SB270/70 showed the lowest temperature compared to other specimens, up to 160 °C. Furthermore, YSZ/polysilazane thermal conductivity and adhesion properties could be enhanced by a prolonged curing time and higher temperature. This study emphasizes that the modification of particle size, YSZ content, time, and temperature curing is a promising strategy to improve the thermal properties of TBCs., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The utilization of adhesive compounds in bonding lightweight and high-performance composite structures, including carbon fiber reinforced polymer (CFRP) composites, has garnered significant attention from researchers. This study presents the novel application of Al 2 O 3 coated with TiO 2 as a thermal protective layer for CFRP substrate. Initially, the CFRP substrate underwent a protective treatment involving the application of Al 2 O 3 as a middle coat, followed by a further protective layer consisting of TiO 2 as a top coat. The deposition of TiO 2 onto an Al 2 O 3 -based thermal barrier coating (TBC) was carried out utilizing the flame spray method. The use of a TiO 2 coating as a top coat was employed to enhance protection and heat dispersion across the middle coat and substrate. In order to achieve sufficient adhesion between the CFRP substrate, an intermediate coat consisting of Al 2 O 3 with a Na 2 SiO 3 binder, the impact of varying nozzle distances on adhesion strength and pull-off test outcomes was investigated, with a nozzle distance of 180 mm yielding the highest adhesion strength. The thermal stability of a CFRP substrate was enhanced through the deposition of a layer of TiO 2 on Al 2 O 3 . The surface and cross-sectional morphologies of the composite were analyzed using a Scanning Electron Microscope (SEM). It was observed that the presence of a TBC on the composite surface effectively reduced the amount of heat that was transferred to the composite material. In order to assess the effectiveness of TBC on CFRP substrates, a series of experiments involving thermal torch and conductivity tests were undertaken. The interaction between the top and middle coats of a composite material results in enhanced mechanical properties, hence improving its thermal insulation capabilities. The artificially produced TBC coatings have the potential to function as adhesive materials, ensuring the sustained high performance of CFRP substrates., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

This study proposes the development of a spatio-temporal model with geographic weights containing elements of location, time and the correlation between the two. The spatio-temporal model is a spatial regression model that combines geographic information and time series simultaneously. The model can overcome the problem of spatial heterogeneity and spatial effects. The spatial temporal model used is the Geographically Weighted Panel Regression (GWPR) model with a within estimator. Therefore, it is necessary to determine the best geographic weighting with the optimal bandwidth value and the lowest Cross Validation (CV). The geographic weights used were the Gaussian kernel function, the Bisquare kernel function and the exponential kernel function. Estimation of spatio-temporal model parameters using Weighted Least Square (WLS). The GWPR model was applied to food security index data in 34 Indonesian provinces. The problem of food security is an important problem to be solved in Indonesia, one way is to find the factors that influence the food security index through spatio-temporal modeling. This study consists of data exploration, descriptive statistics, spatial mapping distribution, selection of geographic weights and GWPR modeling. The results showed that the spatio temporal statistical model of GWPR was more accurate with a good model of 92.78 % and a Root mean Square Error value of 3.41. Some highlights of the proposed approach are., Competing Interests: The authors devlare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier B.V.)

By-products from the non-ferrous industry are an environmental problem; however, their economic value is high if utilized elsewhere. For example, by-products that contain alkaline compounds can potentially sequestrate CO 2 through the mineral carbonation process. This review discusses the potential of these by-products for CO 2 reduction through mineral carbonation. The main by-products that are discussed are red mud from the alumina/aluminum industry and metallurgical slag from the copper, zinc, lead, and ferronickel industries. This review summarizes the CO 2 equivalent emissions generated by non-ferrous industries and various data about by-products from non-ferrous industries, such as their production quantities, mineralogy, and chemical composition. In terms of production quantities, by-products of non-ferrous industries are often more abundant than the main products (metals). In terms of mineralogy, by-products from the non-ferrous industry are silicate minerals. Nevertheless, non-ferrous industrial by-products have a relatively high content of alkaline compounds, which makes them potential feedstock for mineral carbonation. Theoretically, considering their maximum sequestration capacities (based on their oxide compositions and estimated masses), these by-products could be used in mineral carbonation to reduce CO 2 emissions. In addition, this review attempts to identify the difficulties encountered during the use of by-products from non-ferrous industries for mineral carbonation. This review estimated that the total CO 2 emissions from the non-ferrous industries could be reduced by up to 9-25%. This study will serve as an important reference, guiding future studies related to the mineral carbonation of by-products from non-ferrous industries., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Plant herbs specifically serai wangi (SW) and peppermint (PPM) are selected for its insect repellent properties as the use of chicken manure (CM) in anaerobic digestion (AD) potentially attract flies due to the digestate produced. Hence, the addition of SW and PPM in the AD system of CM could deter flies' infestation while producing biogas. Previous work has shown that AD of sawdust (SD) and CM with these plant herbs were able to produce biogas and reduce the flies attraction towards the digestate. However, the combination of SW and PPM for AD of CM has yet to be investigated. This work describes the effect of mixing SW and PPM on the co-AD of SDCM with respect to biogas production, methane yield and kinetic analysis. The mixture of SW and PPM was varied at different concentrations. The composition of methane in biogas was characterized every 10 days by using gas chromatography (GC) equipped with a thermal conductivity detector (TCD). The results suggest that co-AD of 10SW10PPM exhibited the highest biogas production (52.28 mL/g vs ) and methane yield (30.89 mL/g vs ), which the purity of methane increased by 18.52% as compared to SDCM. However, increasing the concentration of SW and PPM does not significantly improve the overall process. High R 2 (0.927-0.999), low RMSE (0.08-0.61) and low prediction error (<10.00%) were displayed by the modified Gompertz, logistic and Cone models. In contrast, Monod and Fitzhugh model is not preferred for the co-AD of SDCM with a mixture of SW and PM, as a high prediction error is obtained throughout the study. Increasing the dosage of PPM decreases the maximum cumulative methane yield, ranging from 31.76 to 7.01 mL/g vs for modified Gompertz and 89.56 to 19.31 mL/g vs for logistic model. The Modified Gompertz obtained a lag phase of 10.01-28.28 days while the logistic model obtained a lag phase of 37.29-52.48 days., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (© 2023 The Authors.)

Agricultural waste is considered a promising source for bacterial cellulose production. This study aims to observe the influence of TiO 2 nanoparticles and graphene on the characteristic of bacterial cellulose acetate-based nanocomposite membranes for bacterial filtration in waters. Bacterial cellulose was produced from the pineapple peel waste using fermentation process. High-pressure homogenization process was applied to reduce bacterial nanocellulose size and esterification process was carried out to produce cellulose acetate. Nanocomposite membranes were synthesized with reinforcement of TiO 2 nanoparticles 1 % and graphene nanopowder 1 %. The nanocomposite membrane was characterized using an FTIR, SEM, XRD, BET, tensile testing, and bacterial filtration effectiveness using the plate count method. The results showed that the main cellulose structure was identified at the diffraction angle 22° and the cellulose structure slightly changed at the peak of diffraction angles of 14° and 16°. In addition, the crystallinity of bacterial cellulose increased from 72.5 % to 75.9 %, and the functional group analysis showed that several peak shifts indicated a change in the functional group of membrane. Similarly, the surface morphology of membrane became rougher with the structure of mesoporous membrane. Moreover, adding TiO 2 and graphene increases crystallinity and bacterial filtration effectiveness of nanocomposite membrane., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Heru Suryanto reports financial support was provided by Universitas Negeri Malang. Heru Suryanto reports a relationship with Universitas Negeri Malang that includes: employment. All co-author is researchers who collaborate in Riset Kolaborasi Indonesia Program and I am as principal researcher in this project. All co-author has collected and analyzed the data according to their qualification and my recommendation., (Copyright © 2023 Elsevier B.V. All rights reserved.)

River water has become contaminated with numerous hazardous compounds due to the rapid rise in population and industry expansion. Due to unchecked population growth and the improper disposal of electroplating industrial waste, issues with river water filtration and the elimination of chromium contamination have developed. Various technologies have been developed to overcome these problems. One of the technologies that have been proposed until now is membrane technology. On the other hand, the waste from plastic bottles, which grows yearly and now weighs 381.73 million tons, can create thin films or layers. Therefore, there is a lot of potential in employing plastic bottle trash as a low-cost, sustainable, and eco-friendly membrane material. In this study, the immersion-precipitation phase inversion method was used in the membrane preparation process from plastic bottle waste by modifying fillers (zeolite-NaY) and additives (LiCl and PEG-400) to improve membrane performance. The effect of filler and additive modification on the fabricated membrane was studied for its performance in water purification and chromium ion contaminant removal. The results demonstrated that the modified LiCl membrane performed optimally for water purification and the removal of chromium ions, along with a reduction in turbidity to 1.42 NTU (from 400 NTU) and a 54.75% removal of chromium., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The presence of microplastics (MPs) in marine environments has become increasingly apparent. Owing to the lack of effective solid waste management, Indonesia is the second largest producer of ocean plastic waste after China. Currently, information about pollution of MPs in the sediments of East Surabaya, Indonesia, is not available, and this issue is addressed in this study for the first time. Sediment samples were collected from 16 sampling sites along urban and mangrove coastal areas. MPs were observed in most of the sampling sites, with abundances ranging from ND (not detected) to 598 items/kg. MP shapes constituted fragments (30%), foam (28%), granules (22%), and fibers (20%). The 500-1000 µm fraction was the dominant size of MPs. Polypropylene was the major polymer constituent, followed by high-density polyethylene and polyethylene. Findings from Spearman's correlation coefficients, principal component analysis, and hierarchical cluster analysis reveal that the spatial pattern of MPs is closely related to coastal characteristics and population density. MPs in different coastal regions were assessed by the polymer risk index. Results reveal that coastal areas in the Bulak district exhibit the highest risk. Our results confirm the prevalence of MPs as anthropogenic pollutants in East Surabaya and highlight the importance of management action and education on environmental protection for the mitigation of MP pollution.

As part of our project on exploring Indonesian medicinal plants for antidiabetic and anticancer agents, this study was conducted to investigate the total phenolic and flavonoid contents, and antioxidant, cytotoxic and antidiabetic properties of R. tomentosa leaf extracts. The antioxidant activity was tested using DPPH, ABTS, and FRAP methods. In vitro cytotoxic assay was performed against MCF-7, HeLa, A549, and B16 cancer cell lines. The in vitro antidiabetic testing was determined using α-glucosidase and α-amylase inhibitory evaluation, while STZ-induced diabetic rats were used for in vivo study. The highest values of total phenolic (191.97 ± 0.19 mg GAE g -1 ) and flavonoid (29.11 ± 0.05 mg QE g -1 ) contents were recorded in methanolic extract. This extract also showed the highest DPPH and ABTS activities with IC 50 values of 7.79 ± 0.03 and 4.03 ± 0.02 μg mL -1 , respectively, as well as the highest FRAP activity with a value of 64.05 ± 0.54 μM Fe 2+ g -1 . The methanol extract had cytotoxicity against MCF-7, HeLa, A549, and B16 cancer cell lines with IC 50 values of 123.49 ± 0.79, 28.28 ± 0.17, 168.88 ± 1.14, and 42.44 ± 0.18 μg mL -1 , respectively. In vitro antidiabetic evaluation indicated that the MeOH extract inhibited α-glucosidase and α-amylase with IC 50 values of 45.73 ± 1.06 and 41.31 ± 1.12 μg mL -1 , respectively. A dose of 400 mg kg -1 body weight of the MeOH extract reduced rats' blood glucose rate and serum blood glucose by 48.51% and 17.73%, respectively after 15 days of treatment. Taken together, these findings suggested that the methanolic extract of R. tomentosa leaves can be used as a potential source of antioxidant, cytotoxic, and antidiabetic agents., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

We report on the localization of the initially excited electronic state within the molecular framework of a series of [Ru(bpy) 2 dppz] 2+ derivatives (bpy:2,2'-bipyridine, dppz: dipyrido-phenazine) as sensitizers in NiO based photocathodes. The introduction of conjugated linkers with phenylene and triazole moieties in the bpy ligand sphere separates the NiO surface from the metal center and hence is considered to stabilize the charge separated state, which results from light-driven hole injection. However, introduction of the conjugated linkers also alters the localization of the excess electron density in the excited state within the ligand sphere and impacts the extent to which the charge-separated state is formed. The study emphasizes that tuning the ligand with the lowest-energy π* orbital distal or proximal to the NiO surface significantly affects the initial charge-separation and the solar cell performance. The stability of the charge-separated state correlates with the observed photocurrents in dye-sensitized solar cells. Furthermore, the study challenges the widely accepted concept that the introduction of extended anchoring groups, i.e. increasing Ru - NiO distance, stabilizes the charge-separated state and suppresses charge recombination at the metal-oxide molecule interface., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The integration of gallium nitride (GaN) nanowire light-emitting diodes (nanoLEDs) on flexible substrates offers opportunities for applications beyond rigid solid-state lighting (e.g., for wearable optoelectronics and bendable inorganic displays). Here, we report on a fast physical transfer route based on femtosecond laser lift-off ( fs -LLO) to realize wafer-scale top-down GaN nanoLED arrays on unconventional platforms. Combined with photolithography and hybrid etching processes, we successfully transferred GaN blue nanoLEDs from a full two-inch sapphire substrate onto a flexible copper (Cu) foil with a high nanowire density (~10 7 wires/cm 2 ), transfer yield (~99.5%), and reproducibility. Various nanoanalytical measurements were conducted to evaluate the performance and limitations of the fs -LLO technique as well as to gain insights into physical material properties such as strain relaxation and assess the maturity of the transfer process. This work could enable the easy recycling of native growth substrates and inspire the development of large-scale hybrid GaN nanowire optoelectronic devices by solely employing standard epitaxial LED wafers (i.e., customized LED wafers with additional embedded sacrificial materials and a complicated growth process are not required)., Competing Interests: Conflict of interestThe authors declare no competing interests., (© The Author(s) 2021.)

A conductive polymer (poly(p-phenylenevinylene), PPV) was covalently modified with Ru II complexes to develop an all-polymer photocathode as a conceptual alternative to dye-sensitized NiO, which is the current state-of-the-art photocathode in solar fuels research. Photocathodes require efficient light-induced charge-transfer processes and we investigated these processes within our photocathodes using spectroscopic and spectro-electrochemical techniques. Ultrafast hole-injection dynamics in the polymer were investigated by transient absorption spectroscopy and charge transfer at the electrode-electrolyte interface was examined with chopped-light chronoamperometry. Light-induced hole injection from the photosensitizers into the PPV backbone was observed within 10 ps and the resulting charge-separated state (CSS) recombined within ~ 5 ns. This is comparable to CSS lifetimes of conventional NiO-photocathodes. Chopped-light chronoamperometry indicates enhanced charge-transfer at the electrode-electrolyte interface upon sensitization of the PPV with the Ru II complexes and p-type behavior of the photocathode. The results presented here show that the polymer backbone behaves like classical molecularly sensitized NiO photocathodes and operates as a hole accepting semiconductor. This in turn demonstrates the feasibility of all-polymer photocathodes for application in solar energy conversion.

In a slow sand filter, a biological layer consisting of alluvial mud and various types of microorganisms grows and attaches to the sand media and forms a matrix called schmutzdecke . Changes to several factors, including the quality of raw water, filtration speed, and the addition of media, affect the performance of the slow sand filter unit in producing treated water. Geotextiles can be equipped to improve the performance of a slow sand filter in removing pollutants. The selection of several factors that affect slow sand filter performance can be used as a starting point for the engineering system to determine the best pattern of performance behavior. This approach was carried out by looking at the dynamic behavior patterns of slow sand filter system performance in treating raw water. This research has not yet been conducted extensively. The dynamic behavior pattern approach to the performance of the slow sand filter unit was used to obtain the behavior model for the schmutzdecke layer on the filter. The system dynamic approach focused on treatment scenarios that can determine the behavior of the slow sand filter system. Several factors were assessed, including temperature, turbidity, nutrient concentration, algal concentration, bacteria and dissolved oxygen. Model simulation results show that the comparison of C: N: P values affected the performance of the schmutzdecke layer in removing total coli. The slow sand filter unit was capable of producing treated water with a total amount of coli equal to 0 on the C: N: P values of 85: 5.59: 1.25, respectively, and a 9 cm geotextile thickness., (© 2020 The Author(s).)

Cassia alata or locally known as Ketepeng Cina (Indonesia) and Gelenggang (Malaysia) has been used as a traditional medicine to treat various diseases, especially skin diseases. In addition, C. alata has been reported to have potential anti allergic, anti inflammatory, antioxidant, anticancer, antidiabetic, and antifungal. Metabolite compounds that have been isolated from C. alata include flavones, flavonols, flavonoids glycosides, alatinon, alanonal and β-sitosterol-β-D-glucoside. The compounds have been isolated mainly from the leaves. Further identification is needed to discover the secondary metabolites from other parts of the plant such as seed, flower and bark which are reported to have potent antibacterial and antifungal activity. Therefore, this article highlights the secondary metabolites and biological activity of this plant which has been shown to have pharmacological properties against selected diseases., (© 2020 Published by Elsevier Ltd.)

Leakage is undesirable in water distribution networks, as leaky pipes are financially costly both to water utilities and consumers. The ability to detect, locate, and quantify leaks can significantly improve the service delivered. Optical fibre sensors (OFS) have previously demonstrated their capabilities in performing real-time and continuous monitoring of pipe strength leak detection. However, the challenge remains due to the high labour cost and time-consuming process for the installation of optical fibre sensors to existing buried pipelines. The aim of this paper is to evaluate the feasibility of a submersible optical fibre-based pressure sensor that can be deployed without rigid bonding to the pipeline. This paper presents a set of experiments conducted using the proposed sensing strategy for leak detection. The calibrated optical fibre device was used to monitor the internal water pressure in a pipe with simultaneous verification from a pressure gauge. Two different pressure-based leak detection methods were explored. These leak detection methods were based on hydrostatic and pressure transient responses of the optical fibre pressure sensor. Experimental results aided in evaluating the functionality, reliability, and robustness of the submersible optical fibre pressure sensor.

A series of thiocyanate-free bis(tridentate) ruthenium(II) complexes incorporating 1,2,3-triazole-derived NNN-, NCN-, and CNC-coordinating ligands has been employed for sensitizing ZnO photoanodes for dye-sensitized solar cells (DSSCs). Additionally, the first use of the TEMPO + /TEMPO (2,2,6,6-tetramethyl-piperidine-1-oxyl) redox mediator as a surrogate for the I 3 - /I - redox couple in ZnO nanostructured DSSCs is presented. Compared with I 3 - /I - -based electrolytes, shorter charge lifetimes and diffusion lengths were determined for the TEMPO + /TEMPO-based electrolyte. Nonetheless, similar power conversion efficiencies (PCEs) were achieved with both electrolytes for the RuNCN and RuCNC complexes, whereas higher PCEs are enabled by the iodine-free electrolyte in case of RuNNN. The combination of the molecular sensitizers and the TEMPO-based electrolyte exhibits relatively high external quantum efficiency (EQE) and promising PCEs, ranging from 4.48 to 1.47 %, which are-in part-comparable to that of ZnO-DSSCs with the benchmark N749 black dye. The TEMPO-based electrolyte also exhibits less absorption compared with its I 3 - /I - counterpart, a favorable feature for enhancing the light harvesting ability of the photoanode. Furthermore, the results show the effect of the dye-sensitization procedure on the PCE values: The use of ethanol as the solvent compared with methanol increases the DSSC's efficiency, which is attributed to improved chemisorption of the sensitizer onto the ZnO surface., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)