bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of stereovision on a saddle-shaped membrane structure in aero-elastic wind tunnel test
Authors: Sun Xiaoying , Wu Hangzi , Shan Baohua
Published: March 2020

Some conventional measurements (e.g., accelerometer) are usually used to measure the aero-elastic responses of membrane structures in the field of civil engineering, which are usually measured by using contact sensors, and just one-dimensional data of a single point can be obtained. To deal with this disadvantage, a stereovision measurement is equipped after putting forward a series of algorithms. This newly formed measurement is adopted to measure the aero-elastic responses of a saddle-shaped membrane structure. Before measuring, a series of observations are carried out and discussed by considering the characteristic of the test model, wind tunnel, and interference from the inflow, which is merely mentioned in the previous research. Finally, the full field distribution of average displacement of membrane, under different wind directions and wind speeds, is given. The time history of full field displacement distribution is also presented as a gif file. This successful application implies that when adopting such a stereovision measurement system, it is necessary to optimize the installation of cameras. After an appropriate installation design, the proposed stereovision measurement will make up the disadvantages of conventional measurements and can obtain the full field aero-elastic responses of membrane structures.
A closer look at turbulence spreading: How bistability admits intermittent, propagating turbulence fronts
Authors: Heinonen R. A. , Diamond P. H.
Published: March 2020

In magnetic fusion plasmas, mounting evidence suggests the possibility of sustained turbulence below the linear stability threshold or more generally global turbulence bistability. The usual reduced models for turbulence spreading are unistable/supercritical and incompatible with this result. The older models also cannot realistically support fronts connecting laminar and turbulent domains. In this work, a minimal model for “subcritical” turbulence spreading is introduced and analyzed. The model may be viewed as phenomenological or derived directly by considering the effect of profile corrugations in an E × B staircase. The model, which is related to the FitzHugh–Nagumo system, supports the robust coexistence of multiple turbulence levels via bistability. We show that this model predicts stronger penetration of turbulence into a linearly stable region as well as the formation of intermittent turbulence fronts that resemble avalanches. We derive the critical size that a localized slug of turbulence must exceed in order to spread. Finally, we make a prediction of global hysteretic behavior associated with the bistability, which should be testable via experiment.
Study of magnetocaloric effect and critical exponents in polycrystalline La0.4Pr0.3Ba0.3MnO3 compound
Authors: Mazumdar Dipak , Das Kalipada , Das I.
Published: March 2020

Magnetic and magnetocaloric effects of the polycrystalline La0.4Pr0.3Ba0.3MnO3 (LPBMO) compound were extensively studied. The critical parameters were extracted from the magnetic isotherms data near the paramagnetic–ferromagnetic phase transition region. The values of the critical exponents were compared with the standard theoretically predicted universality classes of magnetism. Interestingly, the critical parameters exhibit anomalous nature compared to the standard models. Such a discrepancy was analyzed considering the effect of disorder present in the studied compound. Moreover, the material shows moderate values of the relative cooling power and refrigerant capacity. Additionally, we have also calculated the temperature-averaged entropy change and normalized refrigerant capacity for the studied LPBMO compound.
Setting the stage for theoretical x-ray spectra of the H2S molecule with multi-configurational quantum chemical calculations of the energy landscape
Authors: Ertan Emelie , Lundberg Marcus , Sørensen Lasse Kragh , Odelius Michael
Published: March 2020

In the H2S molecule, the interplay between different core levels can be investigated in great detail in relation to x-ray spectroscopy, which requires a theory for interpretation. Hence, valence and core excitations into the two antibonding molecular orbitals of the H2S molecule have been calculated within a multi-configurational wave function framework. Scanning along the S–H stretching coordinates, we derive potential energy surfaces and transition dipole moments involving the ground state and core and valence excited states. Both valence excitations and the S1s−1 and S2p−1 core excitations show pairs of dissociative and bound electronic states. These pairs of states are nearly degenerate in H2S at the ground state geometry. The close degeneracy together with conical intersections makes H2S an interesting target for x-ray spectroscopy involving ultra-fast dissociation influenced by non-adiabatic transitions and interference. For future investigations with x-ray absorption spectroscopy (XAS) and resonant inelastic x-ray scattering (RIXS), it is valuable to compare H2S with the water molecule, which exhibits state-selective gating to different vibrational modes [R. C. Couto et al., Nat. Commun. 8, 14165 (2017)] in its well-separated O1s−1 core excited states. The dense manifolds of the S2p−1 core excited states will complicate the analysis of Kα edge RIXS, but dynamical effects could be evaluated through detuning and by comparing with L edge XAS. In L edge RIXS, the dynamical effects will be more pronounced due to the longer lifetime of the S2p−1 core excited states compared to the S1s−1 core excited states.
Dinuclear Lanthanide(III) Complexes Showing Single-Molecule Magnet Behaviour and Optical Properties
Authors: Chen Ruo-Xi , Sun Ou , Xu Yuan-Yi , Qi Yue , Xie Bo-Yu , Gao Ting
Published: March 2020

Three dinuclear lanthanide(iii) complexes with an acetate bridge, which are synthesised by a Salen-type Schiff base and β-diketonate ligands, i.e. [Ln2L2(TTA)4(OAc)2]·CH2Cl2 (Ln=Eu (1), Gd (2), Dy (3); TTA=thenoyltrifluoroacetonate, H2L=N,N′-ethylenebis(salicylideneimine), are investigated. We obtained the structures of complexes 1–3 by X-ray crystallography. Notably, in terms of the structure of these complexes, what is intriguing is that the acetate groups link two Lniii ions, whereas the cadmium ions do not coordinate. Lanthanide-based luminescence is exhibited by complex 1, which exists in both the solid state and a methanol solution. Through magnetic analysis, it is found that a field-induced single-molecule magnet behaviour is exhibited by complex 3, and the energy barrier is shown to be Ueff=45.97K.
Seasonal variations in kissing and sexual activities among men who have sex with men in Melbourne, Australia: implications for seasonal sexually transmissible infection preventions and interventions
Authors: Chow Eric P. F. , Vodstrcil Lenka A. , Fairley Christopher K.
Published: March 2020

Background Previous studies have shown that there is a peak in sexually transmissible infection (STI) cases and sexual activities around summer, but there has been no study examining whether kissing also follows a similar seasonal pattern. The aim of this study was to examine the seasonal patterns of kissing and sex partners among gay, bisexual and other men who have sex with men (MSM). Methods: A short cross-sectional study was conducted among MSM attending the Melbourne Sexual Health Centre between March 2016 and February 2017. Participants were asked to report the number of kissing-only, sex-only and kissing-with-sex male partners in the last 3 months. The mean number of male partners was calculated and stratified by Australia’s seasons. The seasonal trend in the number of partners was assessed by negative binomial regression models. Results: In total, 4391 MSM were included in the analysis. The number of kissing-only and sex-only partners increased significantly from autumn to summer among MSM in Melbourne (Ptrend <0.001). MSM reported the highest number of male partners for kissing-only (mean: 4.91; 95% confidence intervals (CI): 4.78–5.04) and sex-only (mean: 1.91; 95% CI: 1.83–1.99) around summer compared with other seasons. However, the number of kissing-with-sex partners remained stable across seasons. Conclusions: The study data suggest that there is a peak in kissing-only and sex-only partners among MSM around summer and holiday seasons.
Localization of sterols and oxysterols in mouse brain reveals distinct spatial cholesterol metabolism
Authors: Yutuc Eylan , Angelini Roberto , Baumert Mark , Mast Natalia , Pikuleva Irina , Newton Jillian , Clench Malcolm R. , Skibinski David O. F. , Howell Owain W. , Wang Yuqin , Griffiths William J.
Published: March 2020

Dysregulated cholesterol metabolism is implicated in a number of neurological disorders. Many sterols, including cholesterol and its precursors and metabolites, are biologically active and important for proper brain function. However, spatial cholesterol metabolism in brain and the resulting sterol distributions are poorly defined. To better understand cholesterol metabolism in situ across the complex functional regions of brain, we have developed on-tissue enzyme-assisted derivatization in combination with microliquid extraction for surface analysis and liquid chromatography-mass spectrometry to locate sterols in tissue slices (10 µm) of mouse brain. The method provides sterolomic analysis at 400-µm spot diameter with a limit of quantification of 0.01 ng/mm
2
. It overcomes the limitations of previous mass spectrometry imaging techniques in analysis of low-abundance and difficult-to-ionize sterol molecules, allowing isomer differentiation and structure identification. Here we demonstrate the spatial distribution and quantification of multiple sterols involved in cholesterol metabolic pathways in wild-type and
cholesterol 24S-hydroxylase
knockout mouse brain. The technology described provides a powerful tool for future studies of spatial cholesterol metabolism in healthy and diseased tissues.
Programming colloidal bonding using DNA strand-displacement circuitry
Authors: Zhou Xiang , Yao Dongbao , Hua Wenqiang , Huang Ningdong , Chen Xiaowei , Li Liangbin , He Miao , Zhang Yunhan , Guo Yijun , Xiao Shiyan , Bian Fenggang , Liang Haojun
Published: March 2020

Significance

We developed an enthalpy-mediated strategy to control dynamic pathways in colloidal assembly by working at constant temperature, which provides a different option to circumvent metastability that normally causes disordered structures. Using this tractable approach allows colloidal bonding to be programmed for synchronization with colloid assembly, thereby realizing the optimal programmability of DNA-functionalized colloids. Moreover, the dynamic conversion of the colloidal identity can be easily achieved using this method, i.e., the conversion of colloid-A to colloid-B during colloidal assembly. This approach represents an important step for nanoscientists to manipulate colloidal bonds to create complex and functional nanoscale materials, just as chemists manipulate atomic bonds to synthesize complex and functional molecules.
Active volume regulation in adhered cells
Authors: Adar Ram M. , Safran Samuel A.
Published: March 2020

Significance

Living cells regulate their volume using a diverse set of mechanisms to maintain their structural and functional integrity. The most widely used mechanism to control cell volume is active ion transport. Recent experiments on adhered cells reveal that their volume is significantly reduced as their basal area is increased. Our physical theory includes electrostatics and cell activity to obtain the osmotic pressure within the cell. We predict a generic relation for how adhered cells regulate their volume in response to changes in their basal area. The theory is in agreement with the recent experiments on different cell types.
Robot-Mediated Interviews
Authors: Wood Luke Jai , Dautenhahn Kerstin , Rainer Austen , Robins Ben , Lehmann Hagen , Syrdal Dag Sverre
Published: March 2020

In recent years the possibility of using humanoid robots to perform interviews with children has been explored in
a number of studies. This paper details a study in which a potential real-world user trialled a Robot-Mediated Interviewing system
with children to establish if this approach could realistically be used in a real-world context. In this study a senior
educational psychologist used the humanoid robot Kaspar to interview ten primary school children about a video they had watched
prior to the interview. We conducted a pre and post interview with the educational psychologist before and after using the system
to establish how the system worked for him and the perceived potential for real-world applications. The educational psychologist
successfully used the system to interview the children and believed that principally using a small humanoid robot to interview
children could be useful in a real-world setting provided the system was developed further.
Final report of the CCEM-K2.2012 key comparison of resistance standards at 10 MΩ and 1 GΩ.
Authors: Sanchez Carlos , Wendler Kai
Published: March 2020

An international comparison of dc resistance at 10 MΩ and 1 GΩ was carried out under the framework of the Mutual Recognition Arrangement (MRA) of the Comité Consultatif d'Électricité et Magnétisme (CCEM). The comparison was piloted by the National Research Council of Canada (NRC) with the participation of 12 National Metrology Institutes (NMIs). Two 10 MΩ resistors (Measurements International, model 9331) and two 1 GΩ resistors (Measurements International, model 9331S) were used as travelling standards. Although the uncertainty at 10 MΩ was limited by the stability of the travelling standards, the comparison achieved a reduction in the uncertainties of the degrees of equivalence relative to the 2002 CCEM-K2 comparison, especially at 1 GΩ where the improvement was quite significant.

Main text

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Statistical method in quark combination model *
Authors: Yang Yang-Guang , Song Jun , Shao Feng-Lan , Liang Zuo-Tang , Wang Qun
Published: March 2020

We present a new method for solving the probability distribution for baryons, antibaryons, and mesons at the hadronization of the constituent quark and antiquark system. The hadronization is governed by the quark combination rule in the quark combination model developed by the Shandong Group. We employ the method of the generating function to derive the outcome of the quark combination rule, which is significantly simpler and easier to generalize than the original method. Furthermore, we use the formula of the quark combination rule and its generalization to study the property of the multiplicity distribution of net-protons. Taking a naive case of quark number fluctuations and correlations at hadronization, we calculate ratios of multiplicity cumulants of final-state net-protons and discuss the potential applicability of the quark combination model by studying hadronic multiplicity fluctuations and the underlying phase transition property in relativistic heavy-ion collisions.
Comparative study of the forward and backward methods for calculating jet properties in pp collisions at √s=7 TeV *
Authors: Yan Yu-Liang , Limphirat Ayut , Zhou Dai-Mei , Srisawad Pornrad , Yan Yupeng , Yang Chunbin , Cai Xu , Sa Ben-Hao
Published: March 2020

We propose a forward method based on PYTHIA6.4 to study the jet properties in ultra-relativistic pp collisions. In the forward method, the partonic initial states are first generated with PYTHIA6.4 and then hadronized in the Lund string fragmentation model, and finally the hadronic jets are constructed from the created hadrons. Jet properties calculated with the forward method for pp collisions at

=7 TeV are comparable to those calculated with the usual anti-

algorithm (backward method) in PYTHIA6.4. The comparison between the backward and forward methods may contribute to the understanding of the partonic origin of jets in the backward method.
Modeling the quasi-periodic oscillation of Swift J1644+57
Authors: Zheng Meng-Meng , Yi Shuang-Xi , Wang Fa-Yin , Zou Yuan-Chuan
Published: March 2020

A 200-second X-ray quasi-periodicity in the 2 – 8 keV band from Swift J1644+57 was found by Reis et al. From the onset time of quasi-periodic oscillation (QPO), we show that Swift J1644+57 is a plunging event. This QPO may be related to discrete clumps from the accretion disk falling into a supermassive black hole, then the outflow in the jet may be also discontinuous. We estimate the lifetime of clumps to be about several hundreds seconds and the fraction of clumpy ejecta to be about 30% from the QPO. The other possible model involves the interface between the inflow and jet magnetosphere in the magnetically choked accretion flow. Theory and numerical simulations indicate that a magnetic Rayleigh-Taylor and Kelvin-Helmholtz unstable magnetospheric interface can produce a jet-disk QPO mechanism. This event may be the first evidence of jet-disk QPO. From observations, the two models are comparable.
Super-resolution X-ray imaging with hybrid pixel detectors using electromagnetic source stepping
Authors: Dreier T. , Lundström U. , Bech M.
Published: March 2020

With increasing demand for high-resolution X-ray images, the super-resolution method allows to estimate a single high-resolution image from several low-resolution images. Hybrid pixel detectors provide high-quality and low-resolution images, which makes them particularly well suited for super-resolution. However, such detectors consist of a limited number of pixels at high cost. Applying super-resolution with hybrid pixel detectors shows that it is a viable method to obtain high-resolution images. The point-spread function of such detectors can be idealised to be 1 pixel, adding no blur into the image making such detectors the ideal choice for the application of super-resolution X-ray imaging. However, there are charge sharing effects between the pixels caused by the energy and impact position of incoming photons. Utilising an X-ray source, which allows magnetic stepping of the X-ray spot, several slightly shifted images can be obtained without requiring mechanical movements. Registering the shifts between individual images with sub-pixel precision allows to estimate a high-resolution image. With repeatable and equally spaced X-ray spot position patterns, sufficient information can be obtained with only a few images. In this paper, we present the application of super-resolution for X-ray imaging using a Pilatus 100K hybrid pixel detector from Dectris Ltd. and a prototype micro-focus X-ray source from Excillum AB. Moreover, we analyse the image quality for applications in X-ray radiography and tomography. Using a sufficient number of low-resolution images allows us to achieve an increase in resolution, without introducing significant blur or artefacts into the image. Here we quantify the effects on the quality of resulting super-resolution images using different methods of image interpolation, interpolation factors, shifts of the sample on the detector, and amount of low-resolution images.
The global distribution of seagrass meadows
Authors: McKenzie Len J , Nordlund Lina M , Jones Benjamin L , Cullen-Unsworth Leanne C , Roelfsema Chris , Unsworth Richard K F
Published: March 2020

Seagrass meadows globally are under pressure with worldwide loss and degradation, but there is a growing recognition of the global importance of seagrass ecosystem services, particularly as a major carbon sink and as fisheries habitat. Estimates of global seagrass spatial distribution differ greatly throughout the published literature, ranging from 177 000 to 600 000 km2 with models suggesting potential distribution an order of magnitude higher. The requirements of the Paris Climate Agreement by outlining National Determined Contributions (NDC’s) to reduce emissions is placing an increased global focus on the spatial extent, loss and restoration of seagrass meadows. Now more than ever there is a need to provide a more accurate and consistent measure of the global spatial distribution of seagrass. There is also a need to be able to assess the global spread of other seagrass ecosystem services and in their extension, the values of these services. In this study, by rationalising and updating a range of existing datasets of seagrass distribution around the globe, we have estimated with Moderate to High confidence the global seagrass area to date as 160 387 km2, but possibly 266 562 km2 with lower confidence. We break this global estimate down to a national level with a detailed analysis of the current state of mapped distribution and estimates of seagrass area per country. Accurate estimates, however, are challenged by large areas remaining unmapped and inconsistent measures being used. Through the examination of current global maps, we are able to propose a pathway forward for improving mapping of this important resource. More accurate measure of global #seagrass distribution, critical for assessing current state and trends
PI/NCC Carbon Membrane: Effect of Additives loading Towards Hydrogen Separation
Authors: Sazali N , Mamat R , Siregar J P , Gunawan T , Salleh W N W , Nordin N A H M
Published: March 2020

Incorporating thermally labile polymer-based additives is a facile and practical approach in developing superior carbon membranes. In this study, three different thermally labile polymers, microcrystalline cellulose (MCC), nanocrystalline cellulose (NCC), and polyvinylpyrrolidone (PVP), were introduced separately to P84-copolyimide (PI) solution as additive and their impact on membrane performance were investigated. Firstly, NCC was added as the membrane pore former for hydrogen gas (H2) separation. The addition of NCC significantly increased pore channels in the membrane, hence contributed to high gas permeance and selectivity. The tests involving pure H2 and N2 permeation were carried out at room temperature. Carbon membranes carbonized at a final temperature of 800°C with the heating rate of 3°C/min under Ar flow achieved the greatest H2/N2 selectivity of 434.68±1.39, hence proving the potential of NCC as a good additive.
ADVANCED IN CARBON MEMBRANE BY RELATING TO COATING-CARBONIZATION-CYCLES FOR OXYGEN PERFORMANCE
Authors: Sazali N , Salleh W N W , Ismail N H , Kumaran K , Othman M H D , Harun Z
Published: March 2020

This work discusses the creation and assessment of rounded carbon membrane arranged from P84 co-polyimide mixes with Nanocrystalline cellulose (NCC). In light of earlier examinations, it defined the theory that rounded carbon membrane execution can be controlled by controlling the carbonization parameters. The focal point of this investigation is to acquaint compelling dip-coating strategies with deliver superior rounded carbon membrane. In light of the result of this examination, the coating carbonization cycle (1, 2, 3, and multiple times) has been distinguished as real effect on the separation productivity. Gas separation performance and transport instrument of the carbon membranes were enough assessed by single gas permeation of O2, and N2. In this exploration, use of 2-cycles of coating carbonization has brought about carbon membrane with the most elevated selectivity and O2 penetrability which are 9.29±2.54 and 29.92±1.44 GPU, individually.
Growth and yield of Pleurotus ostreatus using sugarcane bagasse as an alternative substrate in Malaysia
Authors: Ahmad Zakil F , Muhammad Hassan K H , Mohd Sueb M S , Isha R
Published: March 2020

This paper looks at the feasibility of using sugarcane bagasse (SGB) for the cultivation of Pleurotus ostreatus (oyster mushrooms) as an alternative for rubber tree sawdust (RS). Three different compositions of oil palm trunk and rubber tree sawdust were studied with each composition having three replicates. A substrate containing only rubber tree sawdust acted as the control variable. The substrates were supplemented with 5% rice bran and 1.5% calcium carbonate. There are four steps involved in the cultivation of P. ostreatus which were bagging, sterilization, spawning and harvesting the substrates. The mycelia growth, spawn run, pin head formation, yield and biological efficiency were observed. The 100% composition of RS gave the best yield in terms of the mean height of stipe, which was 7.75cm. The mean fresh weight of sawdust was the highest with 50.4g with the number of fruiting bodies around 6. The least yield was recorded for 50% composition of substrates with a mean height of stipe 9.12cm. Among the substrates used, the RS showed the highest biological efficiency with 56.3% followed by 45.1% and 44.8% RS having mixed compositions of 25% and 50% SGB substrates, respectively. Hence, it is proven that in terms of quantity and quality, the unmixed substrates produced better edible mushrooms. However, the results obtained by SGB also showed a great potential as an alternative substrate for the cultivation of P. ostreatus when mixed with RS.
Effect of [emim][BF4] ionic liquid concentration on ionic liquid-polymeric membrane (ILPM) for CO2/CH4 separation
Authors: Mustafa M Z , Mukhtar H , Md Nordin N A H , Mannan H A
Published: March 2020

In the current study, polyethersulfone based (emim)[bf4] ionic liquid polymeric membranes (ILPMs) were synthesised for CO2 separation from CH4. Two weight percentages (10% and 20%) of (emim)[bf4] ionic liquid was added in the prepared doped solution; flat sheet dense membranes were synthesised by the dry phase inversion method. Field Emission Scanning Electron Microscope (FESEM) was used to analyse membranes morphology. Elemental composition of the membranes was examined using Energy Dispersive X-ray (EDX). Distribution of IL in the polymer matrix was observed with the help of mapping. The gas permeation experiments were performed at ambient room temperature and 4 bar pressure. All membranes showed dense and non-porous structure which depicted the good compatibility of polymer and ionic liquid. Presence of additional elements such as nitrogen and fluorine in PES/[emim] [bf4] membranes confirmed the presence of ionic liquid in the polymer. Mapping of fluorine element shown the uniform distribution of ionic liquid in the synthesised ILPMs. Membrane having ionic liquid 20 weight % showed a nearly 39-fold increase in CO2 gas permeability compared to pure polyethersulfone membrane and 2.31-fold increase in ideal selectivity of CO2/CH4. The synthesised ILPMs have immense potential for CO2 separation from natural gas.
Prediction of reservoir sedimentation using Soil Water Assessment Tool (SWAT) towards development of sustainable catchment management
Authors: Abdul Razad A Z , Sidek L M , Jung K , Rahman N F , Shamsuddin S H
Published: March 2020

Sedimentation is considered as one of the major deterioration of a lake or reservoir, resulted from the sediment yield process in the catchment. To control reservoir sedimentation, the most effective method is to control sediment production at sources. This studyis initiated to determine reservoir sedimentation using Soil and Water Assessment Tool (SWAT). Cameron Highlands is an active agricultural area is chosen as study area, where meteorological data from 1997 to 2012 were used to simulate stream flow and sediment load at main rivers feeding into Ringlet Reservoir. Sensitivity analyses were conducted to determine the most sensitive parameters towards flow and sediment load simulation. Calibration and validation were performed from 2001 to 2006 and 2010 to 2012 respectively. Model performance ranges from satisfactory to good, as indicated by R2.0.5, NSE > 0.5, PBIAS <+10% and RSR<0.7. Results are in the form of spatial distribution of flow, sediment load and sediment yield, which are useful to determine problematic sub-catchment to prompt for immediate sediment control measures.
Modelling of swine farm management for enhancement of biogas production and energy efficiency
Authors: Putmai N , Jarunglumlert T , Prommuak C , Pavasant P , Flood A E
Published: March 2020

A conventional all-in/all-out batch management, applied in most small to medium scale swine farming, often provides an inconsistent feed of wastewater for the biogas system, causing imbalance between the farm’s power requirement and its generation capacity. This study proposed two developed models that could be employed to ease this problem. In Model 1, the operation was divided into two batch intervals, while in Model 2, the operation used four separate batches. The developed models helped avoid an unnecessary long lag phase, allowing more stable anaerobic digestion performance, and a more evenly distributed amount of biogas being produced. Accordingly, the developed models more stably supplied energy for domestic use, achieving 36-44% reduction of the electricity expense, or a saving of 43,782 m3 biogas or 35,834 kWh equivalent compared with that of the conventional management. Moreover, excess biogas which occurred in the conventional management, up to 14,714 m3 or 12,043 kWh equivalent at the peak period, could be reduced by 79-100%, evaluated as a greenhouse gas reduction of 9,441 and 11,902 m3CO2eq by Models 1 and 2, respectively. This suggests that without additional investment, more profit could be attained from the significant reduction of operating cost by proper farm management.
Effect of Zeolite NaA additive on the absorption refrigeration unit
Authors: Badarullah B , Abdulrazik A , Nafsun A I
Published: March 2020

Absorption refrigeration has a potential to become among the most effective refrigeration unit due to low power consumption and eco-friendly benefits. However, the problem of relatively lower performance compared to the compressor refrigeration unit has increased the efforts for improvements including working fluid modification and addition of special additive. The purpose of this study was to investigate the effects by adding Zeolite NaA as an additive in the ammonia/water solution in the bench-scale absorption refrigeration system. The additive contains of certain chemicals such as sodium hydroxide, sodium aluminate and sodium metacilicate. The additive was added with different concentrations in the range of 0.2 mM to 0.001 M. From the experiment, the highest COP was calculated to be 6.3 with 0.001 M of additive, while the lowest cooling box temperature was recorded to be 20°C with 0.6 mM additive and 1.5 of COP. The ratio of ammonia and water solution was 30/70% by volume for the obtained result which could be subjected to further research.
Biogas production for electricity from fruit waste: a case study of Gemah Ripah biogas plant, Yogyakarta
Authors: Marendra F. , Pramudikto D.A. , Rahmada A. , Rimbawan H.J. , Cahyono R. B. , Ariyanto T.
Published: March 2020

Gemah ripah biogas (GRB) plant is the first biogas project in Indonesia that utilizes a 100% fruit waste as a feedstock. Now, the biogas has been operating for almost 9 years. To get objective performance study in the biogas plant existing, it important to analyze biogas production, electricity generation and energy and environmental benefits of the GRB plant. This paper presents a comprehensive analysis of the typical demonstration model in utilization of fruit waste. Regarding the observation, technically GRB has operated in appropriate function. GRB was designed for 4 T/day feed and supplies 148.5 kWh/day electricity. The further analysis exhibited that GRB project is required to be optimized for maximum energy and environmental benefits because biogas plant feed only 0.35 T/day (8% of feed design) and supplies electricity only 0.45 % of its supplies. For biogas quality, data showed that the biogas plant produces methane and carbon dioxide with average content of 59% and 37% which is already within a good standard. GRB need some of recommendation for maximum operation which is discussed in this article. Nevertheless, operating as an example of a sustainable renewable energy model, GRB can decrease of waste discharge to the landfill and utilization of waste at the source. The operation model of GRB plays an important role in reducing greenhouse, mitigating pollution and generating renewable energy.
Modeling of CO2-MEA absorption system in the packed column using Sulzer DX structured packing
Authors: Shahid Muhammad Zubair , Maulud Abdulhalim Shah , Azmi Bustam M , Suleman Humbul
Published: March 2020

The accurate design of a packed column is largely dependent upon the accurate calculation of the effective mass transfer area (ae
) of a packing. The experimental and the modelling study for the packed column with CO2-Monoethanolamine (MEA) system has been reported by employing Sulzer DX packing. The model validation results revealed that the modification in the available simple ae
correlations is necessary to attain the reliable results using Sulzer DX packing. Recently, a new simple ae
correlation suitable for Sulzer DX packing with MEA-CO2 system has been reported. Therefore, in the present study, the rate-based model is developed using the newly developed ae
correlation for the packed absorption column with Sulzer DX structured packing for CO2-MEA system. The model has been successfully validated with the experimental data. Overall results depict good accuracy (AAD < 15%) of predicted CO2 concentration profiles due to the reliable ae
calculations. However, the relative accuracy is low at high liquid flowrates (> 8 m3/m2h) due to the design limitations of the ae
correlation. Therefore, in this study, the adopted ae
mass transfer correlation is found suitable for the reliable modelling of the packed absorption column with Sulzer DX packing.
Product Distribution and Characteristic from Pyrolysis of Indonesia Palm Oil Residues
Authors: Cahyono R. B. , Adhityatama G. I. , Persada G.B. , Prasetya A. , Ariyanto T.
Published: March 2020

During the production, palm oil industry generated around 4 ton of dry biomass waste such empty fruit bunch (EFB), palm kernel shell (PKS), and palm oil fiber (PF) for each 1 ton of palm oil extracted. As main industry in Indonesia, palm oil industry offered not only the oil product but also biomass waste which was potential for clean energy sources. The utilization of those biomass residue is still limited due to lack of information related to conversion method as well as characteristic of various product. This research focuses on the product distribution and characterization of biomass pyrolysis especially PKS and PF. Pyrolysis experiments were conducted using both thermogravity (TG) method and stainless steel reactor at temperature range of 450–550°C. Based on the TG method that biomass was heated up until 1000°C in nitrogen atmosphere, PKS exhibited slower decomposition process rather than PF because of high value of hardness and fixed carbon. Two strong peaks were seen clearly which the first peak correspond to hemicellulose and lignin decomposition that proceed in the temperature range of 200 – 300°C. While, the second peak represented to cellulose and lignin decomposition that occurred in the temperature range of 300 – 500°C. Pyrolysis at higher temperature initiated smaller amount of solid product due to volatilization and higher ash content. The ash composed of several chemical such as Si, Al, Ca, Mn etc which would still remain in the solid product when temperature was increased. However, the fixed carbon and heating value enhanced significantly as increasing temperature. Clearly, based on the SEM images, the biochar hold better pore structure compared to raw material. In the pyrolysis process, the volatile matter moved to gas phases and create abundant vacant as pore structure in the solid product. These results offers opportunities of better utilization of palm oil residues not only energy conversion but also other area such as adsorbent, bio-fertilizer/soil conditioning.
Effect of storage condition on color, vitamin C content, polyphenol content and antioxidant activity in fresh soursop pulp (Annona muricata L.)
Authors: Tran N Y T , Nhan N P T , Thanh V T , Chinh N D , Tri D L , Nguyen D V , Vy T A , Truc T T , Thinh P V
Published: March 2020

Annona muricata Linn. (soursop) belongs to the Annonaceae family. This plant has been traditionally used for the treatment of various infectious and inflammatory diseases. In this study, the effect of storage conditions (room and cold condition) on Annona muricata nutrients was evaluated on the basis of color, vitamin C, polyphenol content and antioxidant activity (DPPH). The change in Lab* brightness (64.34 ± 4.18a, -4.61 ± 0.31a, 12.80 ± 0.57a for fresh sample) was negligible during the 10 day cooling process (66.22 ± 2.33ab, -0.58 ± 7.89a, 9.03 ± 0.85b). These criteria have not changed compared to the original sample after 2 days. The effect of room temperature on properties of Soursop was significant. After 8 and 10 days, it was impossible to quantify TAA, TPC and ABTS of the sample. The values of the two samples (8 and 10 days) at low temperatures were respectively 4.46 ± 0.35 and 3.27 ± 0.33 (TAA); 3.00 ± 0.05 and 2.64 ± 0.30 (TPC); 0.66 ± 0.01 and 0.69 ± 0.04 (free-radicals scavenging capacity). The appearance and morphology of the samples are also graphically described.
Optimization of Osmotic Dehydration Process for Aonla (Emblica officinalis Gaertn) Pieces with Salt Solution and Spices by Response Surface Methodology
Authors: Nagamaniammai G , Udhayaganga M , Swetha S , Ramasamy K
Published: March 2020

The optimization of osmotic dehydration process ofaonla(Emblica officinalisGaertn) slices in brine solution containing spices (cumin powder, fenugreek powder, fresh ginger extract) was carried out using response surface methodology. The independent process variables for osmotic dehydration are salt concentration in water (4-12%), spices concentration in the brine solution (39%), solution to fruit ratio (3-5) and duration of 60-90 minutes at room temperature. The osmotic dehydration process was optimized for maximum water loss, solute gain, overall acceptability and minimum acidity and vitamin C loss based on the RSM. The optimum conditions were predicted as 12% salt concentration, 7.09 % spices concentration, 4.30 solutions to fruit ratio and 84.15 minutes process time. Among the process variable, salt concentration, process duration and spices concentration have the most significant effect on water loss, solute gain, acidity and overall acceptability; process time has the most effect on vitamin-C loss and acidity whereas solution-to-fruit ratio had significantly lower effect on all the responses. Osmotically dehydratedaonlasamples were observed to be less in functional compounds compare to freshaonlasamples due to leaching out of minor compounds to hypertonic solution during osmotic dehydration process.
Effect of Torrefaction Conditions on Physicochemical Properties of Empty Fruit Bunches
Authors: Sukiran M A , Wan Daud W M A , Abnisa F , Nasrin A B , Loh S K
Published: March 2020

Empty fruit bunches (EFB) in current bulky form are low in energy density and highly moist making them unsuitable as a solid fuel. Pre-treatment of EFB via thermochemical process i.e. torrefaction is required in order to improve its energy density via reduction of moisture and oxygen contents, which eventually will lead to an increased calorific value (CV). This study investigated the effects of temperature (225 °C, 250 °C and 300 °C) and retention time (20, 40 and 60 min) on the torrefaction products distribution (solid, liquid and gas) and physicochemical properties including proximate and ultimate (elemental) compositions and energy content of torrefied EFB. The results indicated that an increased temperature and retention time led to lower mass of torrefied EFB yield. The highest yield (90.44%) was attainable after 20 min of torrefaction at the lowest deployed 225 °C. However, the CV of torrefied EFB increased with increasing temperature and retention time, reaching a maximum 25.73 MJ/kg at 300 °C for 60 min, i.e. up to 46% higher than its raw form. The resulting improved physicochemical properties indicated suitability of the torrefied EFB for bioenergy processes such as combustion, gasification, pyrolysis and peptization.
Synthesis and Enhancement of Thermal Conductivity of Surfactant Free MWCNTs-Jatropha Oil-based Nanofluid
Authors: Rehman W U , Mercian Z M A , Bhat A H , Guan B H , Sulaimon A A , Khan I U , Ullah H , Mukhtar A , Saqib S , Hameed A , Yasir M , Ahmad A
Published: March 2020

Thermal conductivity enhancement of multi-walled carbon nanotubes (MWCNTs) based nanofluids received the attention of many researchers due to its remarkable thermal properties. However, the synthesis of surfactant-free multi-walled carbon nanotubes based nanofluids with higher dispersion stability to maintain a trade-off between its dispersion stability and thermophysical properties is still a challenge. In this research, a surfactant-free multi-walled carbon nanotube and Jatropha seed oil-based nano-dispersion are prepared via one-step method and subjected to experimental determination of thermal conductivity within the temperature range of (25 °C - 65 °C) and nanoparticle volume fraction range of (0.2 wt.% - 0.8 wt.%). The prepared nanofluid found to be highly stable for long time and its thermal conductivity enhancement was found to be 6.76%.
Screening of extraction buffer concentration for protease extraction from the leaves of Syzygium polyanthum using full factorial design
Authors: Yahya Noorhafiza , Arshad Zatul Iffah Mohd , Mudalip Siti Kholijah Abdul , Sulaiman Siti Zubaidah , Man Rohaida Che , Shaarani Shalyda Md , Rahim Mohd Hairul Ab.
Published: March 2020

This study aimed to identify the factors that significantly affect the extraction of protease from the leaves of Syzygium polyanthum. The extraction of protease from the leaves of Syzigium polyanthum was studied at different concentration of substances in the extraction buffer. A 24 full factorial experimental design was performed. The effect of four independent operating factors including; A, the concentration of potassium phosphate (KPO4); B, the concentration of Triton X-100; C, the concentration of glycerol; and D, the concentration of dithiotreitol (DTT) on the protease activity were evaluated statistically. All regression models gave a good fit to the experimental data (R2 > 99%). The maximum protease activity was detected when the extraction was performed using 3.0 M KPO4, 1% Triton X-100, 80% glycerol and 1.5 M DTT. The results revealed that the concentration of KPO4, DTT, and their interaction were statistically significant to affect the protease activity. Thus, the results obtained from this study indicate that full factorial design is useful to screen the significant factors and minimise the number of experiments.
Removal of chemical oxygen demand (COD) and total suspended solid (TSS) using electrocoagulation process for treatment of oleochemical wastewater
Authors: Azli F A M , Azoddein A A M
Published: March 2020

Wastewater from oleochemical industry contains high concentration glycierin, chemical oxygen demand (COD) and total suspended solids (TSS) that can cause environmental pollution if discharged without proper treatment method. Currently, oleochemical industry used reverse osmosis membrane and submerged bed biofilm reactor to treat their wastewater. In this work, other method namely electrocoagulation treatment that capable to achieve a high removal of color, COD, biological oxygen demand (BOD) is employed. The objective of the study is to determine the optimum operating condition such as initial pH (6-9), applied current (4.0-8.0A), type of electrode (aluminium & stainless steel & and retention time (10 – 40 min) on degradation of COD and TSS in wastewater from an oleochemical industry using this process. The experimental results showed that the pollutant removal efficiencies of COD and TSS can be achieved at 62.64% and 66.12% respectively, of the initial concentration of parameters using aluminium electrode at the optimum conditions of pH 7.5, applied current 6 A and reaction time of 30 min. All the findings of the study revealed that treatment of oleochemical wastewater by electrocoagulation process at optimum conditions can be used as a treatment.
MHD free convection boundary layer flow near the lower stagnation point flow of a horizontal circular cylinder in ferrofluid
Authors: Yasin S H M , Mohamed M K A , Ismail Z , Salleh M Z
Published: March 2020

The present numerical solution is to theoretically investigate the magnetohydrodynamic (MHD) free convection boundary layer flow and the heat transfer of ferrofluid near the lower stagnation point of a horizontal circular cylinder. The conventional heat transfer of fluids such as water and oil is inherently the poor heat transfer performance. Nanofluid which is formed by magnetic nanoparticles is known as ferrofluid and has shown a particular achievement when the effect of external magnetic is applied. For this purpose, ferrofluid that contains magnetite, Fe3O4 and water are considered. The dimensional governing equations are transformed by using non-dimensional variables and non-similar transformations to form nonlinear partial differential equations. The numerical solution using the implicit finite difference scheme namely Keller-box method is used to solve the nonlinear partial differential equations. Numerical results on velocity and temperature distributions as well as the quantity of interest of pertinent parameters such as magnetic parameter and the volume fraction of ferroparticles parameter are discussed. It is noticeable that the reduced Nusselt number of ferrofluid decreases through the increase of magnetic parameter strength.
A significant review on different cooling agent during rapid cooling process of low carbon steel
Authors: Mohd Saaroni M A , Sazali N , Ghazali M F
Published: March 2020

Low carbon steel has been chosen as the engineering material in this project to research the comparison of the effects of cooling agent during rapid cooling process and to develop a mechanical data of low carbon steel after the heat treatment. This material has been chosen because it is mostly used for deep drawing of motor car bodies, motor cycle parts and other domestic applications where it need to involve the desired mechanical properties processes. Rapid cooling process or quenching is common process to obtain certain material properties such as increasing strength and hardness. This process is widely used in industry to obtain required properties of any application.
The effect of material on bipolar membrane fuel cell performance: A review
Authors: Daud S S , Norrdin M A , Jaafar J , Sudirman R
Published: March 2020

Bipolar membrane fuel cell (BPMFC) was firstly discovered in 2000 that composed of two-layered ionic conducting membranes. The importance of BPMC development is its ability to humidify the cell when operating at a high current density that eliminates the use of the external humidification system. It is able to self-humidify the cell because of water formation at the intermediate layer from the reaction of hydrogen ion (H+) with hydroxide ion (OH−). Up to now, there is no commercial bipolar membrane (BPM) in water formation configuration for the fuel cell humidifying purpose. Thus, the researcher had come out with a composition of proton exchange membrane with anion exchange membrane by the hotpressing method that allows them to carry the proton and anion simultaneously in a single cell. There are a few of polymeric-based PEM and AEM material had been selected for developing BPM such as Nafion, FumaPEM FAA3, quaternary ammonium polysulfone (QAPSF), and quaternary ammonium poly(phenylene)oxide (QAPPO). This review aims to determine the effect of material selection and design for developing BPM toward its performance in fuel cell based on published works. Besides, the potentialities of polymeric-based material are discussed, pointing out the main positive and negative effect of this BPM for fuel cell applications. As a case study, the use of different types of PEM and AEM material for BPM is particularly stressed, pointing out the main properties for its applications in BPMFC.