bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental study on age and gender differences in microscopic movement characteristics of students*
Authors: Wang Jiayue , Boltes Maik , Seyfried Armin , Tordeux Antoine , Zhang Jun , Weng Wenguo
Published: July 2021

Campus security has aroused many concerns from the whole society. Stampede is one of the most frequent and influential accidents in campus. Studies on pedestrian dynamics especially focusing on students are essential for campus security, which are helpful to improve facility design and emergency evacuation strategy. In this paper, primary and middle school students were recruited to participate in the single-file experiments. The microscopic movement characteristics, including walking speed, headway, gait characteristics (step length, step frequency and swaying amplitude) and their relations were investigated. Age and gender differences in the headway-speed diagram and space requirements were analyzed by statistical tests. The results indicated that the impacts of age and gender were significant. There were three stages for the influence of gender on the headway-speed diagram for both age groups. The impacts on students’ space requirements were consistent for different age and gender groups. But the impacts of age and gender on free-flow speed were affected by each other. Due to the connection of walking speed and gait characteristics, the comparisons of gait characteristics between different ages and genders were performed to understand the corresponding differences in speed more deeply. The results showed that differences in step length and swaying amplitude between males and females were significant for both age groups. The effect of gender on step frequency was significant for primary students. But for middle school students, whether gender had significant impact on step frequency was not clear here because of the large P-value. Besides, the influence of age on gait characteristics changed with gender.
Lattice Boltzmann model for interface capturing of multiphase flows based on Allen–Cahn equation
Authors: Wang He , Tian Fang-Bao , Liu Xiang-Dong
Published: July 2021

A phase-field-based lattice Boltzmann model is proposed for the interface capturing of multi-phase flows based on the conservative Allen–Cahn equation (ACE). By adopting the improved form of a relaxation matrix and an equilibrium distribution function, the time derivative ∂t
(ϕ u
) induced by recovering the diffusion term in ACE is eliminated. The conducted Chapman–Enskog analysis demonstrates that the correct conservative ACE is recovered. Four benchmark cases including Zalesak’s disk rotation, vortex droplet, droplet impact on thin film, and Rayleigh–Taylor instability are investigated to validate the proposed model. The numerical results indicate that the proposed model can accurately describe the complex interface deformation.
Synthesis and thermoelectric properties of Bi-doped SnSe thin films*
Authors: Pang Jun , Zhang Xi , Shen Limeng , Xu Jiayin , Nie Ya , Xiang Gang
Published: July 2021

Bi doped n-type SnSe thin films were prepared by chemical vapor deposition (CVD) and their structure and thermoelectric properties were studied. The x-ray diffraction patterns, x-ray photoelectron spectroscopy, and microscopic images show that the prepared SnSe thin films were composed of pure SnSe crystals. The Seebeck coefficients of the Bi-doped SnSe were greatly improved compared to that of undoped SnSe thin films. Specifically, Sn0.99Bi0.01Se thin film exhibited a Seebeck coefficient of –905.8 μV⋅K−1 at 600 K, much higher than 285.5 μV⋅K−1 of undoped SnSe thin film. Further first-principles calculations reveal that the enhancement of the thermoelectric properties can be explained mainly by the Fermi level lifting and the carrier pockets increasing near the Fermi level due to Bi doping in the SnSe samples. Our results suggest the potentials of the Bi-doped SnSe thin films in thermoelectric applications.
Secondary electron emission yield from vertical graphene nanosheets by helicon plasma deposition
Authors: Jin Xue-Lian , Ji Pei-Yu , Zhuge Lan-Jian , Wu Xue-Mei , Jin Cheng-Gang
Published: July 2021

The secondary electron emission yields of materials depend on the geometries of their surface structures. In this paper, a method of depositing vertical graphene nanosheet (VGN) on the surface of the material is proposed, and the secondary electron emission (SEE) characteristics for the VGN structure are studied. The COMSOL simulation and the scanning electron microscope (SEM) image analysis are carried out to study the secondary electron yield (SEY). The effect of aspect ratio and packing density of VGN on SEY under normal incident condition are studied. The results show that the VGN structure has a good effect on suppressing SEE.
Analysis on diffusion-induced stress for multi-layer spherical core-shell electrodes in Li-ion batteries*
Authors: Yan Siyuan , Li Chuanwei , Qi Zhifeng , Xin Lipan , Li Linan , Wang Shibin , Wang Zhiyong
Published: July 2021

Silicon-based carbon composites are believed as promising anodes in the near future due to their outstanding specific capacity and relatively lower volume effect compared to pure silicon anodes. Herein, a multilayer spherical core–shell (M-SCS) electrode with a graphite framework prepared with Si@O-MCMB/C nanoparticles is developed, which aims to realize chemically/mechanically stability during the lithiation/delithiation process with high specific capacity. An electrochemical-/mechanical-coupling model for the M-SCS structure is established with various chemical/mechanical boundary conditions. The simulation of finite difference method (FDM) has been conducted based on the proposed coupling model, by which the diffusion-induced stress along both the radial and the circumferential directions is determined. Moreover, factors that influence the diffusion-induced stress of the M-SCS structure have been discussed and analyzed in detail.
Interrogation of optical Ramsey spectrum and stability study of an 87Sr optical lattice clock
Authors: Xia Jing-Jing , Lu Xiao-Tong , Chang Hong
Published: July 2021

The optical Ramsey spectrum is experimentally realized in an 87Sr optical lattice clock, and the measured linewidth agrees well with theoretical expectation. The coherence time between the clock laser and the atoms, which indicates the maximum free evolution period of using Ramsey detection to measure the atom-laser phase information, is determined as 340(23) ms by measuring the fringe contrasts of the Ramsey spectrum as a function of the free evolution period. Furthermore, with the same clock duty cycle of about 0.1, the clock stability is measured by using the Ramsey and Rabi spectra, respectively. The experimental and theoretical results show approximately the same stability as the two detection methods, which indicates that Ramsey detection cannot obviously improve the clock stability until the clock duty cycle is large enough. Thus, it is of great significance to choose the detection method of a specific clock.
Phase transition-induced superstructures of β-Sn films with atomic-scale thickness*
Authors: Lei Le , Cao Feiyue , Xing Shuya , Dong Haoyu , Guo Jianfeng , Gu Shangzhi , Geng Yanyan , Mi Shuo , Wu Hanxiang , Pang Fei , Xu Rui , Ji Wei , Cheng Zhihai
Published: July 2021

The ultrathin β-Sn(001) films have attracted tremendous attention owing to its topological superconductivity (TSC), which hosts Majorana bound state (MBSs) for quantum computation. Recently, β-Sn(001) thin films have been successfully fabricated via phase transition engineering. However, the understanding of structural phase transition of β-Sn(001) thin films is still elusive. Here, we report the direct growth of ultrathin β-Sn(001) films epitaxially on the highly oriented pyrolytic graphite (HOPG) substrate and the characterization of intricate structural-transition-induced superstructures. The morphology was obtained by using atomic force microscopy (AFM) and low-temperature scanning tunneling microscopy (STM), indicating a structure-related bilayer-by-bilayer growth mode. The ultrathin β-Sn film was made of multiple domains with various superstructures. Both high-symmetric and distorted superstructures were observed in the atomic-resolution STM images of these domains. The formation mechanism of these superstructures was further discussed based on the structural phase transition of β to α-Sn at the atomic-scale thickness. Our work not only brings a deep understanding of the structural phase transition of Sn film at the two-dimensional limit, but also paves a way to investigate their structure-sensitive topological properties.
Barrier or easy-flow channel: The role of grain boundary acting on vortex motion in type-II superconductors*
Authors: Liu Yu , Gou Xiao-Fan , Xue Feng
Published: July 2021

Grain boundaries (GBs), as extremely anisotropic pinning defects, have a strong impact on vortex motion in type-II superconductors, and further on the macro level dominates the superconductivity for example the critical current density. Many previous studies indicated that mostly GB plays the role of a strong barrier for vortex motion, while an easy-flow channel just under some certain conditions. In order to thoroughly make clear of the questions of what is exactly the role of GB on vortex motion and how it works, in this article we developed a large scale molecular dynamic model and revealed the action of GB on vortex motion in type-II superconductors. The most significant finding is that the role of GB on vortex motion can be changeable from a barrier to an easy-flow channel, and which is intrinsically determined by the competition effect correlated with its action on vortex between in the GB and no-GB regions. Such the competition effect essentially depends on the attributes of both the GB (described by the GB strength and angle θ) and no-GB pining regions (by the relative disorder strength α
p/α
v). Specifically, for a YBa2Cu3O7 – x
(YBCO) sample, to obtain a clear knowledge of vortex motion in GB region, we visualized the three typical trajectories of vortices during the three vortex movement stages. Further, in order to understand how GB results in the macro current-carrying property, corresponding to the current–voltage relation of the YBCO conductor, we obtained the average velocity vy
of vortices varying with their driving force, which is nearly identical with the previous observations.
Ultrabroadband mid-infrared emission from Cr2+:ZnSe-doped chalcogenide glasses prepared via hot uniaxial pressing and melt-quenching*
Authors: Xia Ke-Lun , Jia Guang , Gan Hao-Tian , Gui Yi-Ming , Zhang Xu-Sheng , Liu Zi-Jun , Shen Xiang
Published: July 2021

We reported an ultrabroadband mid-infrared (MIR) emission in the range of 1800 nm–3100 nm at room temperature (RT) from a Cr2+:ZnSe-doped chalcogenide glasses (ChGs) and studied the emission-dependent properties on the doping methods. A series of Cr2+:ZnSe/As40S57Se3 (in unit wt.%) glass-ceramics were prepared by hot uniaxial pressing (HUP) and melt-quenching methods, respectively. The glass-ceramics with MIR emission bands greater than 1000 nm were successfully prepared by both methods. The effects of matrix glass composition and grain doping concentration on the optical properties of the samples were studied. The occurrence state, morphology of the grains, and the microscopic elemental distributions were characterized using x-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive spectrometer (EDS) analyses.
Sensitivity enhancement via vacuum squeezed injection in Advanced Virgo
Authors: Angelo B D’
Published: July 2021

Modern gravitational-wave astronomy is based on the Michelson interferometer design, for which a key towards enhancement of the sensitivity is to reduce the noise which arises from different sources. As it was first proposed by Caves, injected squeezed states can be used to reduce the measurement shot noise, thus improving the sensitivity in the high-frequency band. This result was achieved with the German-British interferometer GEO600 in Hannover, and Advanced Virgo joined the third observational run on April 2019 with its operating source of squeezed vacuum producing an improvement in the high-frequency sensitivity up to 3 dB (the horizon for a Binary-Neutron Star detection increases by 2-4 Mpc).
Detection of Bacillus cereus genes responsible for diarrheal and emetic toxins
Authors: Saeed Ban M.S. , Abbas Basil A. , Al-Jadaan Shaker A.N.
Published: July 2021

Bacillus cereus isolated from different food sources. The diarrheal toxin genes such as cytK, hemolytic enterotoxin (hblA, hblC and hblD), non-hemolytic enterotoxin (nheA, nheB and nheC), bceT and entFM in addition to emetic toxin gene were detected by PCR. The cyt K gene was observed in 94.87 % of the isolates. entFM and emetic toxin gene were found very rare in all food samples at the percentage 2.56% and 7.69% respectively. Uncooked rice which has a highest number of bacterial isolation, also showed relatively high percentage of the cytK and bceT genes (90%). These two genes present in 100% of Bacillus cereus isolates in most food samples. Bacteria isolated from burger meat contain all investigated genes.
Automated supplier risk evaluation system
Authors: Schelegia E P , Fleşer T
Published: July 2021

One key aspect in the manufacturing process is the monitoring of the third-party suppliers, a potential disruption in this component would have an impact on the whole chain of manufacturing and potentially have risks in monetary aspects and reputation loss. Even though stated by contract delivery dates and the quality of the delivery content might vary in between shipments even with well-established providers due to technological changes of changes in the quality process. To minimize this risk and to partially take out the subjective human factor, the current paper proposes the implementation of an impartial observer system that based upon a set of key performance indicators will assign a trust rating to each third party. With the option of both human and machine input, the system can be used as an indicator of how reliable the business with a certain entity is and if the risks would be acceptable for a better price offer.
Protection against mechanical risks provided by gloves used by firefighters in intervention actions
Authors: Arvinte C , Hristian L , Burduhos-Nergis D P , Bernevig M A , Toma S L , Sandu I G , Bejinariu C
Published: July 2021

The safety of firefighters during the intervention is determined by the performance of the personal protective equipment used. The behaviour of the materials used in the manufacture of protective gloves under the action of risk factors has a significant influence on the degree of safety it provides to the user. This paper presents the conditions that must be met by materials used in the manufacture of protective gloves for firefighters and describes the results of tensile and abrasion resistance tests obtained in the case of a material on which a treatment has been applied, to increase protective capabilities.
Effect of fibre contents toward manufacturing defects and interfacial adhesion of Arenga Pinnata fibre reinforced fibreglass/kevlar hybrid composite in boat construction
Authors: Suriani M J , Ruzaidi C M , Wan Nik W B , Zulkifli F , Sapuan S M , Ilyas R A , Khalina A , AbuBakar A , Musapha R , Mohd Radzi F S
Published: July 2021

In recent years,Arenga Pinnatafibre has been found with great potential to be used as fibre reinforcement in material matrix composites. This study investigates the effect of fibre contents toward manufacturing defects and interfacial adhesion ofArenga Pinnatafibre reinforced Fiberglass/Kevlar hybrid composite material in boat construction. The composite testing coupons were prepared based on the volume fraction ofArenga Pinnatafibre which are 30%, 45%, 60%, and 75%. The long Arenga Pinnata fibre was placed and arranged into the mould by hand lay-up technique. The testing coupon have been arranged with a thickness of 5mm. Manufacturing defects and interfacial adhesion had determined by Scanning Electron Microscopy (SEM) techniques. The SEM results showed that specimen D (60%) of Arenga Pinnata exhibits the less manufacturing defects with a good interfacial and well bonding between the fibre and matrix among other testing specimens. Meanwhile, specimen E (75%) shows the highest manufacturing defects. As a conclusion, 60% ofArenga Pinnatafibre contents showed less manufacturing defects and exhibited good interfacial adhesion. SEM had significantly determined the manufacturing defects and interfacial adhesion ofArenga Pinnatafibre reinforced Fiberglass/ Kevlar hybrid composite material.
Study of temperature and stresses using finite element analysis in turning of C45 material
Authors: Țîțu A M , Pop A B , Sandu I G
Published: July 2021

Parts machined by high cutting speeds can often exhibit high fatigue strength, increased micro-hardness in the surface layers and plastic deformations, due to the tool cutting edge radius associated with the induced stresses. The changing of rake and clearance angles has an important influence on the chip formation, cutting forces, residual stresses, temperatures in both the workpiece and the tool. International research on the influence of geometric parameters of the tool on the entire cutting process, are of particular importance to understand this process development. The approach of this study, considers the parametric realization of the cutting tool profile - a coated TiC turning chisel, which will be used in the finite element simulation of the orthogonal turning process. Deform 2D application, which is a powerful simulation engine was chosen and allows the correct simulation of the cutting process in real machining conditions. Deform 2D enables the automatically meshing and remeshing generation and also the optimization whenever needed and wherever is required a high accuracy, thereby reducing the overall difficulty of the problem and the computational requirements. Using Lagrangian discretization, the machining process was simulated and made possible to observe and present a series of conclusions and own points of view regarding the temperature distribution at the tool tip and in the workpiece, the effective stresses distribution and the cutting force variation under the rake and clearance angles influences.
Soil respiration strongly offsets carbon uptake in Alaska and Northwest Canada
Authors: Watts Jennifer D , Natali Susan M , Minions Christina , Risk Dave , Arndt Kyle , Zona Donatella , Euskirchen Eugénie S , Rocha Adrian V , Sonnentag Oliver , Helbig Manuel , Kalhori Aram , Oechel Walt , Ikawa Hiroki , Ueyama Masahito , Suzuki Rikie , Kobayashi Hideki , Celis Gerardo , Schuur Edward A G , Humphreys Elyn , Kim Yongwon , Lee Bang-Yong , Goetz Scott , Madani Nima , Schiferl Luke D , Commane Roisin , Kimball John S , Liu Zhihua , Torn Margaret S , Potter Stefano , Wang Jonathan A , Jorgenson M Torre , Xiao Jingfeng , Li Xing , Edgar Colin
Published: July 2021

Soil respiration (i.e. from soils and roots) provides one of the largest global fluxes of carbon dioxide (CO2) to the atmosphere and is likely to increase with warming, yet the magnitude of soil respiration from rapidly thawing Arctic-boreal regions is not well understood. To address this knowledge gap, we first compiled a new CO2 flux database for permafrost-affected tundra and boreal ecosystems in Alaska and Northwest Canada. We then used the CO2 database, multi-sensor satellite imagery, and random forest models to assess the regional magnitude of soil respiration. The flux database includes a new Soil Respiration Station network of chamber-based fluxes, and fluxes from eddy covariance towers. Our site-level data, spanning September 2016 to August 2017, revealed that the largest soil respiration emissions occurred during the summer (June–August) and that summer fluxes were higher in boreal sites (1.87 ± 0.67 g CO2–C m−2 d−1) relative to tundra (0.94 ± 0.4 g CO2–C m−2 d−1). We also observed considerable emissions (boreal: 0.24 ± 0.2 g CO2–C m−2 d−1; tundra: 0.18 ± 0.16 g CO2–C m−2 d−1) from soils during the winter (November–March) despite frozen surface conditions. Our model estimates indicated an annual region-wide loss from soil respiration of 591 ± 120 Tg CO2–C during the 2016–2017 period. Summer months contributed to 58% of the regional soil respiration, winter months contributed to 15%, and the shoulder months contributed to 27%. In total, soil respiration offset 54% of annual gross primary productivity (GPP) across the study domain. We also found that in tundra environments, transitional tundra/boreal ecotones, and in landscapes recently affected by fire, soil respiration often exceeded GPP, resulting in a net annual source of CO2 to the atmosphere. As this region continues to warm, soil respiration may increasingly offset GPP, further amplifying global climate change.
DNA barcoding of Thrixspermum longipilosum based on Internal Transcribed Spacer 2 (ITS2) region
Authors: Rohimah S , Ratnasari T , Su’udi M
Published: July 2021

Thrixspermumis an orchid that has the characteristics of a very short flowering period. This is one of the obstacles in the conventional identification process that uses morphology, both vegetative and generative. For this reason, a molecular approach is needed as an alternative identification tool for theThrixspermumorchid. For molecular identification, CBOL recommends three markers, namelymatK, rbcL, andITS. In this study, onlyITS2was used sinceITShave been reported for its ability to discriminate plant sample up to species levels. The genomic DNA ofT. longipilosumwas isolated using the CTAB method with minor modification, then used as a template in PCR amplification. The amplicon resulted from the PCR reaction (± 450 bp in size) was purified and further determined using DNA sequencer. The results showed thatT. longipilosumhas a high homology level with its close relatives (per ident 94.07%-96.91%). From alignment analysis, theITS2sequence ofT. longipilosumshowing differences nucleotides located in sequences 3 (A→G), 55 (G/A→T), and 64 (A→G). Meanwhile, phylogenetic analysis showed thatT. longipilosumformed one cluster withT. linusii. This shows thatITS2are highly recommended as a molecular marker to determine the barcode of theT. longipilosum.
Preliminary Study on Social Stability Risk Assessment of Land Integrated Renovation Project: A Case Study of Shichuan River Project in Fuping
Authors: Zhou Hang , Xu Yan
Published: July 2021

Many uncertain factors in the construction of major projects may lead to social stability risk events. Taking the land integrated renovation project of Shichuan River (Urban Section) in Fuping as an example, this paper discusses the connotation of social stability risk in the land renovation project, and claims that during the construction and management of the land integrated renovation project of the Shichuan River (Urban Section) the risk of land acquisition and demolition and the risk of environmental damage are the more important risk factors in the identification of social stability risk.
Removal of ammonia in domestic wastewater by using multi soil layering
Authors: Wardani T A K , Sudarno  , Hardyanti N , Syafrudin  , Hadiwidodo M , Wardhana I W
Published: July 2021

Domestic wastewater is the primary source of river pollution. Every human activity in the house must produce waste. Domestic wastewater from the kitchen, bathing, and washing activities contains organic pollutants. The parameter tested was ammonia. In this study, Multi Soil Layering (MSL) was used as a processing method. This treatment serves to reduce ammonia levels in wastewater. This study aims to determine the removal of ammonia in greywater using the Multi Soil Layering System. Wastewater samples were taken in a residential area of Semarang. In this study, there are 2 stages, namely the preparation and implementation stages. In the seeding and acclimatization process, a batch reactor was used for 14-24 days running. The next stage is the process of running for 20 days with intermittent flow. Soil Mixture Box (SMB) is a mixture of andosol soil and activated charcoal (reactor A), andosol soil and apus bamboo (reactor B), and andosol soil, activated charcoal, and apus bamboo (reactor C). The results of domestic wastewater treatment using the MSL method respectively in the three reactors can remove ammonia by 49%, 51%, and 52%.
Learning transformation of the 21st century curriculum for prospective teacher in term of eco-literacy
Authors: Nadiroh N , Zulfa V , Yuliani S
Published: July 2021

The 6 C’s for the 21st century play an essential role in developing an independent learning curriculum in Indonesia: critical thinking, collaboration, communication, creativity, citizenship/culture, and character education/connectivity. This study explores the eco-literacy of prospective teachers in Universitas Negeri Jakarta, especially during the implementation of the 21st Century Curriculum in Indonesia. The method used in this research is a survey method. The results of the study show that critical thinking was the most challenging part of the 6C’s. Several factors lead to critical thinking becoming the most challenging part of achieving by the prospective teacher. Critical thinking skills include the ability to access, analyze, and synthesize information. A combination of these specific skills will lead to a professional critical thinker. So, this study supports relevant research and provides new empirical data that eco-literacy and critical thinking skills can be learned, trained, and mastered. Within eco-literacy and critical thinking, implementing the 21st-century curriculum in terms of environmental education will contribute to preserving the environment. Therefore, the implementation of eco-literacy must begin early.
The implementation of environmental education-based curriculum towards adiwiyata predicate school. Case study: an elementary school in Subang City, West Java, Indonesia
Authors: Anih E , Rachman I , Rohmawatiningsih W , Yayoi K
Published: July 2021

Getting the Adiwiyata predicate is one of the things that schools in Indonesia strive for. But not all schools quickly get this predicate. Preparation and school persistence must be severe to get the Adiwiyata predicate. Many points are assessed in the Adiwiyata program assessment, one of which is implementing curriculum and learning environmental education in schools, whether they are done or not. This study aims to analyze whether the school prepares itself to achieve the goal of being predicated Adiwiyata. This study distributed a questionnaire with 11 questions to principals and teachers of elementary schools in Subang City randomly in 5 districts in Subang. The questions were processed using the cluster analysis, and the level of readiness was analyzed at the point of environmental education-based curriculum implementation. It was found that there were still many schools that had not implemented the environmental education curriculum, both in an integrated manner and in independent subjects. Assistance is needed to carry out supporting learning activities for the Adiwiyata program assessment points. Keywords: environmental education curriculum, adiwiyata.
Instilling environmental literacy using Kamishibai cards in kindergartens
Authors: Susilana R , Dewi L , Rullyana G , Ardiansah  , Kodama Y , Rachman I
Published: July 2021

Environmental literacy is a person’s ability to understand and interpret environmental conditions. Based on the understanding and interpretation, the person can decide to maintain, restore, and improve environmental conditions. The goal of environmental literacy is to develop a generation having awareness of and care about the environment, knowledge, skills, attitudes, motivation, and commitment to work individually and collectively to find solutions to environmental problems. This important ability needs to be instilled from an early age because character education in children is long term. This study research uses the literature review method with data collected from books, official reports, organizational websites, and research reports published in national and international online journals. This study aims to examine and describe the steps in instilling early literacy in learning activities in Kindergarten using Kamishibai as learning media. The results of this literature analysis show that instilling environmental literacy using Kamishibai can be integrated in the 2013 Curriculum and can foster students’ awareness of their environment.
Deceleration of the development of city gas connections amidst the covid-19 pandemic in the metropolitan area
Authors: Prima A , Ridaliani O , Hamid A , Pramadika H , Sanusi H P , Rinanti A
Published: July 2021

The National Energy Policy captured the basis for renewable energy development in Indonesia and also specified a national target for the optimal energy mix. For these fundamental reasons, several unprecedented strategies, blueprints, and collaborations are to be explored in the long term. Apparently, one of the key objectives was to exploit natural gas as the primary and eco-friendly energy resource. This profitable gas was projected to significantly contribute a minimum of 22% of total energy toward enhancing economic growth. Approximately, 10 million city gas connections are required by 2025, in order to achieve the set goals. However, a gap exists between the initially planned city gas connections to the distribution network, and the realization during the Covid-19 pandemic in 2020. This global phenomenon poses a challenge to virtually all economic segments, including energy, as the demand plummeted drastically. Based on Indonesia’s National Energy Policy, the first proposed target was to develop 266,070 gas connections. The project was subsequently adjusted to 127,864. Surprisingly, the realization surpassed the new arrangement by over 6% or was about 135,286. However, the figures obviously comprehended 50.84% of the projects were stalled, contrary to the vision of constructing a minimum of 10 million city gas pipe connections in 2025. This study provided a profound description of the impact of the reduction in abovementioned development on the expected outcome, using the multivariable regression method. The results revealed 96.92% of data from the applied variables were able to describe the developed linear model.
Circular economy of bio compost from coffee waste to support sustainable development goals in alleviating poverty in communities around the Sidoarjo coffee industry
Authors: Bimantara K A , Alauddin S F N , Amalia N , Widialip N F , Citrasari N , Hariyanto S
Published: July 2021

In 2016-2021, coffee consumption in Indonesia was predicted to increase by 120,000 tons, impacting the increase of coffee waste. Several large coffee industries in Indonesia are located in Taman District, Sidoarjo Regency. The character of the coffee skin waste contains 44.87% organic C; N of 1.69%; P of 0.18%; K 2.49%, and C / N ratio 10-14. This value indicates that the waste can be used as compost because it meets the criteria in SNI 19-7030-2004 concerning Compost from Organic Waste. This narrative review aims to determine the circular economy of bio compost from the coffee industry solid waste to support SDGs point 1 in alleviating poverty in communities around the Sidoarjo coffee industry. The research results showed bio compost I and II is the alternative product in the circular economy (W11). The coffee waste, coffee ground, coffee skin, and coffee returned collects waste in the circular economy (W10). The raw material composition of Bio compost I such as 1.5 kg coffee ground: 1.35 kg of coffee returned:0.15 kg coffee skin+3mL of EM4 and Bio compost II such as 4.6 kg SCG’s:0. 4 kg coffee skin+5 ml EM4. In practice, the circular economy of bio compost I and II can involve Farmer Groups or Youth Organizations around the industry in Taman District, Sidoarjo Regency. Based on data 2020, the total members are 113 people, producing compost of 72,435.5 kg/month with a sales profit of IDR 36,217,750. This practice can support the first point of the SDGs, namely poverty alleviation for communities around the coffee industry. However, studies on the exact circular economy pattern of coffee waste in the Sidoarjo Regency are still needed.
School readiness in supporting child-friendly schools reviewed from noise aspect of the classroom in a primary public school in the new normal era
Authors: Syafrudie H A , Haryo A
Published: July 2021

Child-friendly school is an educational program organized by the government of the Republic of Indonesia to fulfill, guarantee and protect children’s rights. A child-friendly school program, ensuring schools can develop children’s interests, talents, and abilities, prepare children to be responsible, tolerant, respectful, and collaborative. One of the elements of a child-friendly school is from the aspect of school infrastructure it is a). rooms in school buildings are protected from glare and light reflection; b). spaces in school buildings are protected from noise; c). there is sufficient lighting in the classroom. The purpose of this study was to map the readiness of 12 schools that were about to participate in the Adiwiyata school competition, whether appropriate or not. The research was conducted in the Malang Regency Education Office, representing the areas of North Malang Regency, South Malang Regency, East Malang Regency, and West Malang Regency. Data obtained by taking direct measurements to the school using a sound meter. The data obtained were analyzed using descriptive statistics. The conclusion that can be drawn is that the schools proposed to participate in the National Adiwiyata program by the Malang District Education Office do not meet the criteria for child-friendly schools. Suggestions that can be submitted to the Malang Regency Education Office for schools with noise levels above the ideal threshold (55 dB) need to be reconsidered
Microplastic pollution in Deli River Medan
Authors: Harpah N , Ageng P , Addauwiyah R , Rizki A , Perdana Z , Suryati I , Leonardo R , Husin A , Faisal M
Published: July 2021

Microplastic is new pollution and made from a synthetic polymer. The Deli River is one of the main rivers in Medan city that flow on urban and suburban areas. This study has aims to identify the characteristics (shape and type), the quantity, and the microplastic correlation with the flow velocity. Sample collected at eight locations based on SNI 03-70160-2004 and preparation in the laboratory with organic digestion and density separation. The microplastic characterized identified with FTIR and microscopy, the quantity identified with microscopy. Analyze the relation tested by Kolmogorov-Smirnov Test and significance tested by Pearson Correlation at a 95% confidence level. The result showed that Deli River contains polyethylene, Polypropylene, and Polystyrene with film and fragment shape dominated. The average microplastic quantity on Deli River Water is 102 particles L-1. The amount of microplastic has a positive correlation with the flow velocity. Most of the microplastic on Deli River Water in Medan came from secondary microplastic.
Current development of cellulose-based biopolymer as an agent for enhancing oil recovery
Authors: Riswati S S , Setiati R , Kasmungin S , Fathaddin M T
Published: July 2021

It is widely accepted that the chemical enhanced oil recovery (EOR) technique, especially polymer flooding, has been successfully implemented and improves oil production in oilfields worldwide. Polymers are injected into the well to increase the viscosity of the displacing fluid. Most of the polymer flooding projects employ synthetic polymer, and the rest uses biopolymer. Considering the environmental concern, it is encouraging to select biopolymer as an EOR agent. This study focuses on the current status of the development of the cellulose-based biopolymer for EOR since cellulose is abundant organic material in nature. Hydroxyethylcellulose (HEC) and Carboxymethylcellulose (CMC) have been utilized in the oil industry, while cellulose nanocrystal (CNC) and cellulose nanofibril (CNF) are recently being introduced as potential EOR agents. The evidence from the previously published data shows that cellulose-based biopolymers can improve oil recovery and have distinct characteristics. This study is a preliminary attempt for further application of cellulose-based biopolymer in EOR.
Distribution pattern of e. coli and total coliform at Tanah Sareal District, Bogor City, Indonesia
Authors: Kairunnisa D , Hendrawan D I , Fachrul M F , Rinanti A
Published: July 2021

Escherichia coli bacteria and Total coliform in groundwater are often the leading cause of diarrhea cases. Some of the factors that cause groundwater pollution are the distance of the septic tank to the well, the presence of pollutants near the well, and poor construction. The purpose of this study was to determine the distribution pattern of E. coli and total coliform. The research was conducted in Tanah Sareal District, Bogor City. There are 11 wells monitored. Counting the number of E. coli and total coliform using APHA 9223 A method with Colilert’s IDEXX. The distribution pattern of E. coli bacteria and total coliform in shallow groundwater is supported by Geographic Information System (GIS) software that ArcGIS based on android. The result shows the number of E. coli 1 - >2500 MPN/100 ml and total coliform 3 - >2500 MPN/100 ml. The distribution of E. coli and total coliform toward to direction to the northwest is influenced by the distance of the well from the septic tank, the presence of pollutants, and population density.
Analysis of PM10 dispersion models from coal-fired power plant activities in North Sumatera by using CALPUFF
Authors: Suryati I , Zulkarnain R , Pratama A
Published: July 2021

Nearly 35% of electricity generation in the North Sumatra region comes from coal-fired steam power plants. The existence of coal-fired power plants also has a negative impact in the form of a decrease in ambient air quality. To determine the pollutant dispersing concentration from the chimney, it can be done by modelling the pollutant disperse pattern. This study uses the CALPUFF model because this model is non-steady state and follows variations in meteorological factors. The research location is in Pangkalan Susu coal-fired power plants with PM10 parameters. The research aims to calculate the concentration of PM10 with CALPUFF and to validate modelling. The results showed that the concentration of the PM10 model obtained was 0.07-0.86 μg/m3, and the observation was 12.77 - 56.45 μg/m3. The CALPUFF model show that the impact distribution area is in the direction of the wind direction of the wind rose and the affected area is in the southwest of the Pangkalan Susu coal-fired power plants. The model validation for d = 0.968, r = 0.922 and FB = 1.962, which means that the CALPUFF model is valid and can be applied to estimate the impact distribution area at Pangkalan Susu coal-fired power plants.
Microbiome analysis of medical mask waste as an early step to prevent environmental pollution due to unstandardized waste treatment strategies
Authors: Rozana K , Susanti E , Saputra I K , Ciptawati E , Kurniawan D T
Published: July 2021

The Covid-19 pandemic caused a large amount of medical mask waste to be buried in the environment. Medical masks are one of the categories of B3 waste that should require a special treatment process. In fact, in the current pandemic conditions, medical mask waste can be found along with household waste without special treatment and separation. Medical masks have the potential to contain pathogenic microbial populations that attack the human respiratory system. On the other hand, microbes themselves are a group of organisms that are susceptible to mutation. Management of medical mask waste that does not comply with B3 waste management standards will have an impact on the emergence of new problems in the future. The purpose of this study was to identify the distribution of microorganism populations in mask waste samples taken randomly from household waste disposal sites. The medical mask waste sample will then be isolated and identified to determine the medical mask waste sample’s microbiome variations. Based on the research results, it was found that 47% of the microorganisms detected were coliform microorganisms, 20% of other organisms were unidentified microorganisms, and the remaining 33% were pathogenic microorganisms.
Covid-19 is impact to air quality transformation based on Landsat: a case from Makassar City, Indonesia
Authors: Muhtar G A , Mariati H , Ridwan  , Hasanuddin  , Sandi R , Okviyani N
Published: July 2021

Makassar is city center in Eastern Indonesia, so that many sectors such as industry, services, settlements, education, trade, and transportation are developing rapidly. These various activities produce exhaust emissions, such as SO2(Sulfur Dioxide) and NOx (Nitrogen Oxide), which can be bad for health. Landsat is a measuring tool used to monitor air quality in a large area. The research objective was to measure changes in SO2and NOx using Landsat 8 OLI in Makassar City before covid (October 2019) and during covid (during PSBB/June 2020 and after PSBB/October 2020). Kruskal Test is used to analyze transformation difference significantly on SO2and NOx before the covid pandemic and during a covid pandemic. The result shows that SO2is higher before covid. That is 220 ppm in October 2019. While covid, it is 42 ppm on June 2020 and 98 ppm on October 2020. The same thing happened to NOx. NOx is higher before covid that is 177 μ/m3. But while covid, it is decreased. That is 173 μ/m3in June 2020 and 175 μ/m3in October 2020. Kruskal Test shows a significant difference between SO2and NOx before and during a covid pandemic.
The study of N:P ratio for estimating nutrient limitation at shallow lakes waters in Depok City West Java, Indonesia
Authors: Fachrul M F , Hendrawan D I , Rinanti A
Published: July 2021

This study aims to analyze the concentration of Nitrate and Phosphate, also the N:P ratio in waters of shallow lakes in Depok City, West Java Province, Indonesia using secondary data collected in 2017 and 2019. In an environment, nitrogen and phosphate sources are fertilizers and wastewater discharged from livestock facilities and sewage from residential areas, which discharge into lakes. The results analysis of nitrate concentration ranged from 0.06– 3.02mg/L and phosphate concentration from 0.004-0.18mg/L. The N:P ratio calculation is known that 8.00-68.00, the value shows that there has been an excessive addition of phosphate elements into the shallow lake waters. Therefore, it appears that the N element is a limiting element that affects the biological conditions of ecosystems such as phytoplankton communities, species composition which is likely to occur dominance of certain types. This situation is quite reasonable, considering that around the lakes are residential areas that discharge domestic wastewater that uses detergents into the lakes. Anthropogenic nitrogen and phosphorus supply to natural ecosystems in shallow lakes in Depok City that the average N:P ratio in 2017 is 40.65 and 2019 is 35.99.
Utilization of lignite coal as heavy metal adsorbent in chemistry laboratory wastewater
Authors: Suliestyah  , Astuti A D , Sari I P
Published: July 2021

Wastewater from Chemistry Laboratory contains heavy metals which need treatment before being discharged into the environment. This study investigates the treatment of chemistry laboratory wastewater using activated carbon. The activated carbon was made from lignite coal with ZnCl2 activation and carbonization was carried out at a temperature of 500°C for 2 hours. The highest iodine number is 1529.20 mg/g on activated carbon with a grain size of 80 mesh of coal and a composition of 40% ZnCl2-60% coal. Adsorption of Fe, Cr and Pb metals using activated carbon was carried out at 2 variations of initial concentrations. At an initial concentration of 75.8 ppm Fe, metal adsorption is 84%, while at an initial concentration of 37.9 ppm it is 87%. The adsorption of Cr metal is 44% at an initial concentration of 1.37 ppm, and it is 79% at an initial concentration of 0.69 ppm. The adsorption of Pb metal is 91% at an initial concentration of 11.2 ppm, and it is 91% at an initial concentration of 5.6 ppm. The results showed that activated carbon from lignite coal could adsorb Fe, Cr and Pb metals, and the initial concentration influenced the effectiveness of metal adsorption.
Drilling waste management using zero discharge technology with Drill Cutting Re-injection (DCRI) method for environmental preservation
Authors: Darajah M H , Karundeng I , Setiati R , Wastu A R R
Published: July 2021

The energy requirement level in Indonesia is quite high. The increasing oil and gas upstream industries to fulfil energy requirement in the future is highly connected with the escalation of wastes, especially drilling wastes. Drilling is one of the main operations in upstream oil and gas industries, which can harm the environment with its various types of wastes. The drilling process produces millions of barrels of wastes each year. However, with the industries being rapidly developed to fulfil national energy requirement, environmental-related regulations for drilling activities have been firmly tightened. Drilling and drilling mud system technology is more sophisticated and the majority of oil drilling companies are starting to adopt environmentally friendly drilling options. The objective of writing this article is to acknowledge the method of drilling waste processing by considering environmentally friendly aspect. Drill Cutting Re-Injection (DCRI) is one of the developing environmentally friendly processing techniques with zero discharge in oil and gas industries. With the utilization of the DCRI process, the companies can produce positive outcomes such as low environmental impact, low safety risks, low transportation problems, and economically cleaning responsibility.
Volumetric calculations for estimating reserves of oil and gas energy resources
Authors: Ardiyansyah M , Triany N , Setiati R , Koesmawardani W T
Published: July 2021

The energy requirement in Indonesia is relatively high. Areas with oil reserves in Indonesia are still available because the existing refineries only produce 60% to 70% of their total production capacity potential. Therefore, it is necessary to estimate potential reserves of existing oil and gas resources, both in exploration areas and in existing oil and gas fields. The oil and gas field evaluation aims to develop oil and gas fields and increase oil and gas production. One of the methods used is the volumetric calculation to estimate oil and gas reserves. This method is used when the available data is incomplete. This method can be used to determine the initial hydrocarbon in place. This method is carried out in the prospect area of the “R” field, South Sumatra, Indonesia. Using porosity, saturation, and formation volume factor from petrophysical data, and bulk volume calculated using the trapezoidal and pyramidal formula from the depth structure map data, initial hydrocarbons in place in prospect area can be estimated at 10.3 MMSTB for oil and 8.55 BSCF for gas. By estimating reserves, we can estimate the potential value of oil and gas resources to fulfill energy needs.