Preliminary Modeling Research Articles

DNA Interaction with Coordination Compounds of Cd(II)containing 1,10-Phenanthroline.

The experimental study of the DNA interaction with three cadmium coordination compounds [Cd(phen)3](CH3CO2)2, [Cd(phen)2(H2O)2](CH3CO2)2, and [Cd2(phen)4(H2O)2](CH3CO2)4 was carried out using spectrophotometry, viscosity, and dynamic light scattering methods. The role of the solution ionic strength (concentration of NaCl) was analyzed. All compounds can penetrate (fully or partly) to the major or minor DNA grooves. It was shown that, in addition to the important role of electrostatic interactions in the formation of the complex, intercalation of the 1,10-phenanthroline ligand occurs for compounds [Cd(phen)2(H2O)2](CH3CO2)2 and [Cd2(phen)4(H2O)2](CH3CO2)4. Compound [Cd(phen)3](CH3CO2)2 binds to DNA externally. The coordination bond between cadmium and DNA was formed in DNA complexes with [Cd2(phen)4(H2O)2](CH3CO2)4. Preliminary computer modeling of the DNA interaction with the compounds used was performed.

Gravity Investigation to Characterize Enceladus's Ocean and Interior

A key objective for the future exploration of the icy moon Enceladus is the characterization of the habitable conditions in its internal ocean. Radio science instrumentation on board a spacecraft in a low-altitude orbit about Enceladus would enable gravity measurements that are fundamental to providing constraints on its internal structure. We present here the concept of operations and expected results of the gravity investigation for a New Frontiers–class mission. Numerical simulations are carried out to determine the gravity field in spherical harmonics to degree and order 30 and the Love number k 2 and its phase. By combining Enceladus’s shape measured by Cassini and the geophysical constraints obtained through the processing of the simulated radio science data, a Bayesian inference network is used for the interior model inversion. Our results indicate that the gravity investigation would enable tight constraints on core radius and density, ocean depth and density, and ice shell rigidity. By assuming a high core rigidity and a preliminary modeling of dissipation in the ice shell, our interior model inversion also yields information on the ice shell viscosity. Further data on the hydrosphere properties might be gathered through optical navigation data by accurately measuring Enceladus’s orientation model.

Characterization of electromigration-induced short-range stress development in Al(0.25 at. % Cu) conductor line

Scanning x-ray microbeam topography and fluorescence experiments were conducted in situ to study the electromigration behavior of a 0.5 μm thick, 10 μm wide, and 200 μm long Al(0.25 at. % Cu) conductor line with 1.5 μm-thick SiO2 passivation on a single crystal Si substrate. The strain sensitivity of x-ray topography measurement allowed detailed examination of the electromigration-induced stress distribution and evolution in the conductor line in response to the depletion of Cu solute early in the electromigration process. Upon electromigration at 0.4 MA/cm2 and 303 °C, a short-range stress gradient was quickly induced by Al migration in the Cu-depleted cathode region to counteract further Al flow. The stress gradient was fully developed during the 5.3 h incubation time, extending over the critical Blech length of about 66 μm from the cathode end. Plastic deformation then occurred at the downstream end of the Cu-depleted region. The preferential electromigration of Cu did not cause detectable stress change outside the Cu-depleted region, except for the significant stress development from the Al2Cu precipitation at the anode end which appeared to initiate the fracture in the passivation. Preliminary finite difference modeling was undertaken to simulate the experimental observations, from which important parameters dictating electromigration in Al(Cu) line were extracted: an apparent effective valence of −5.6 and −1.9 for Cu and Al in Al(Cu), respectively, and a critical Cu concentration of 0.16 at. % above which Al grain boundary diffusion is effectively blocked.

Investigation of low‐disturbance seismic retrofit method for steel column bases using curved members

AbstractSeismic retrofit has always been a very important subject in recent years. However, typical retrofit techniques such as load‐resisting systems, damper devices, and seismic isolation systems will cause considerable disturbances to the structural system, such as increased force demand, and the building's occupants will need to be temporarily relocated during the construction. A design of the low‐disturbance retrofit method for steel column bases that uses the advantages of the curved member has been proposed in the study to improve seismic performance and reduce the mentioned demerits above. The basic mechanism of the curved member retrofit system was first analytically evaluated by preliminary modeling, followed by a parametric study to verify the effective shape. Four curved member specimens were tested with variations in fabrication processes and boundary conditions. Several aspects, including overall behavior, strength backbones, and deformation shapes of the specimens, were examined upon measured responses. The hysteretic performance of the curved member retrofit system is verified to achieve a stable cyclic behavior with limited strength degradation. A set of physical equations for estimating the lateral loads were established and verified by developing numerical models with a good agreement that enabled them to accurately represent the measured responses in the test.

Heat transfer intensification in compact tubular reactors with cellular internals: A pilot-scale assessment of highly conductive packed-POCS with skin applied to the Fischer-Tropsch synthesis

Heat management poses severe constraints when designing non-adiabatic multi-tubular packed-bed reactors for strongly exothermic or endothermic catalytic processes. The exploitation of conduction in the solid matrix of engineered continuous internals (e.g., honeycomb monoliths, open-cell foams, periodic open-cell structures) as a heat transfer mechanism alternative, or possibly additional, to fluid-phase convection, is a promising strategy to relax some of these constraints, offering new opportunities for the intensification of catalytic reactors. Preliminary experimental data and modelling studies show that this is particularly true for compact-scale applications, when conductive internals are packed with catalyst micro-pellets. In this work, through pilot-scale testing, we show that overall heat transfer coefficients as high as 1300 W/m2/K can be achieved in periodic open-cell structures (POCS) made of a highly conductive aluminium alloy, 3D printed with an external continuous skin and packed with 300–400 μm catalyst micro-pellets. To this aim, a Fischer-Tropsch experimental campaign has been carried out in a pilot-scale rig, using an established 20 wt% Co/Al2O3 catalyst formulation and a tubular reactor (28.80 mm I.D., 20 cm catalyst bed length) externally cooled with an isothermal diathermic oil. Thanks to the outstanding heat transfer properties of the packed-POCS reactor, by progressively increasing the oil temperature from 180 °C to 225 °C, once-through CO conversions as high as 70 % have been measured at gas hourly space velocities exceeding 4000 cm3(STP)/h/gcat, resulting in C5+ yields in excess of 0.35 g/h/gcat, with a CH4 selectivity always below 15 %. Such performances, made possible by the intensified heat management granted by the adopted reactor internals, are among the best ever reported for a compact-scale Fischer-Tropsch tubular reactor.

Mitigation of Discharged Capacity Decay and Volume Variation in Vanadium Redox Flow Batteries By Modifying Electrolytes Composition

Vanadium redox flow battery (VRFB) is a promising technology for energy storage because of its independent energy to power ratio and long cycle life. However, VRFB commercialization is still hindered by some technological issues, among which the electrolyte imbalance caused by the undesired vanadium-ions and water transport through the membrane. These phenomena result in battery capacity loss, that can be recovered with periodic re-balancing procedures, thus increasing operating and maintenance costs.In the literature different studies have been dedicated to the analysis of ions and water crossover. In particular, Oh et al [1] evidenced that water and vanadium ions transport across the separator are strictly related. Shin et al [2] tried experimentally to mitigate water imbalance through a modified preparation of the electrolytes; however, the proposed mitigations were experimentally verified for just one charge-discharge cycle.In this work, combining experimental and modelling activity, the evolution of discharged capacity and electrolyte volume were first investigated and then mitigated modifying electrolytes composition for hundreds of cycles. In addition, to increase the validity of the obtained results, three different Solvay® membranes were tested: E98-05 (EW 980, thickness 50 mm), E87-05 (EW 870, thickness 50 mm) and E98-09 (EW 980, thickness 90 mm). Cycles with fixed cut-off voltages at 0.1 A cm-2 were performed in a 25 cm2 cell employing carbon felt electrodes (Sigracell® GFD 2.5 EA thermal activated).Adopting commercial electrolyte, the discharged capacity of the battery dramatically decreased in its first phase of operations, while electrolytes volume continuously varied until the end of the test, as reported in figure 1B for E98-05. This behaviour was showed by all the three different membranes, regardless their thickness or equivalent weight. Thanks to a preliminary modelling analysis with a 1D VRFB physical model, the causes of the initial capacity decay were fully understood and three different mitigation strategies obtained through the modification of electrolyte preparation were proposed and experimentally validated.The first one consisted in the reduction of the initial proton concentration difference between anolyte and catholyte, obtained by increasing the acid molarity at negative side. This led to the mitigation of the initial capacity decay. The second one consisted in the increase of the proton concentration in both the catholyte and anolyte, obtained by increasing their acid molarity. This led to the mitigation of the initial capacity decay and the reduction of the electrolyte volume variation in time.The third mitigation strategy combined the beneficial effect of reducing the initial proton concentration difference between anolyte and catholyte and the one of increasing the proton concentrations in both the electrolytes. The results were promising: as can be seen in figure 1, with E98-05 the initial capacity decay was completely mitigated and no volume variation was experienced in more than 200 cycles. The effectiveness of this mitigation strategy was experimentally validated successfully also with E98-09 and E87-05. Figure 1 - charge-discharge cycle with E98-05 using modified electrolytes: A) discharged capacity; B) electrolyte volume variation.

JWST/NIRSpec Observations of the Coldest Known Brown Dwarf* *Based on observations made with the NASA/ESA/CSA James Webb Space Telescope.

We present 1–5 μm spectroscopy of the coldest known brown dwarf, WISE J085510.83−071442.5 (WISE 0855), performed with the Near-Infrared Spectrograph (NIRSpec) on board the James Webb Space Telescope (JWST). NIRSpec has dramatically improved the measurement of the spectral energy distribution (SED) of WISE 0855 in terms of wavelength coverage, signal-to-noise ratios, and spectral resolution. We have performed preliminary modeling of the NIRSpec data using the ATMO 2020 models of cloudless atmospheres, arriving at a best-fitting model that has T eff = 285 K. That temperature is ∼20 K higher than the value derived by combining our luminosity estimate with evolutionary models (i.e., the radius in the model fit to the SED is somewhat smaller than expected from evolutionary models). Through comparisons to the model spectra, we detect absorption in the fundamental band of CO, which is consistent with an earlier detection in a ground-based spectrum and indicates the presence of vertical mixing. Although PH3 is expected in Y dwarfs that experience vertical mixing, it is not detected in WISE 0855. Previous ground-based M-band spectroscopy of WISE 0855 has been cited for evidence of H2O ice clouds, but we find that the NIRSpec data in that wavelength range are matched well by our cloudless model. Thus, clear evidence of H2O ice clouds in WISE 0855 has not been identified yet, but it may still be present in the NIRSpec data. The physical properties of WISE 0855, including the presence of H2O clouds, can be better constrained by more detailed fitting with both cloudless and cloudy models and the incorporation of unpublished 5–28 μm data from the Mid-infrared Instrument on JWST.

RESEARCH OF AUDIO AND VIDEO TRAFFIC THE CHARACTERISTICS IN LOW-BANDWIDTH RADIO COMMUNICATION NETWORKS

The construction of mass service systems, namely automated control systems, requires preliminary analysis and modeling of traffic in their communication networks. Mathematical models of various types of traffic have been developed for public networks, which allows to estimate the necessary functional characteristics of equipment for building a communication network, depending on the number of users. Low-bandwidth communication networks, which are built on the basis of ultra high frequency and very high frequency (UHF/VHF) radio stations, are distinguished by low speed, high delay and jitter of data transmission. To work in such communication networks, special data transmission protocols are adapted and developed. In this paper, a study of the characteristics of audio and video traffic in low-bandwidth communication networks is carried out, which are built on the basis of UHF/VHF radio stations, which will allow creating a software implementation of simulated traffic modeling for the further determination of the services availability at the stage of planning and designing the communication system. Two personal computers and two modern RF‑7850M-HH UHF/VHF radio stations were used to study the characteristics of audio traffic. The radio stations worked in three operating modes: narrowband mode with a fixed carrier frequency FF, narrowband mode with pseudo-random adjustment of the operating frequency QL1A, and wideband mode ANW2C. The voice was transmitted in digital mode using the built-in MELP 2400 codec, and the "iperf-v2.0.5" software was used to determine the characteristics of the audio traffic on personal computers connected to these radio stations. Two personal computers, two modern RF‑7850M‑HH UHF/VHF radio stations, a video encoder and a video camera were used to study video traffic characteristics. The radio stations operated in ANW2C broadband mode. To evaluate the characteristics of the video traffic, the Wireshark software was used on a personal computer, with the help of which the video broadcast from the video encoder was presented. It was found that voice transmission in low-speed communication networks based on UHF/VHF radio stations occupies a bandwidth of 2 Kbit/s - 2.5 Kbit/s, and when voice and data are simultaneously transmitted in radio stations, data buffering and jitter increase. The resolution, bitrate, FPS, and necessary bandwidth of video traffic that can be transmitted via UHF/VHF radio communication channels are determined. Based on the conducted research, recommendations are provided for the transmission of video traffic through low-bandwidth communication channels.

Modeling of analytical, preparative and industrial scale counter-current chromatography separations

Analytical, preparative and industrial scale counter-current chromatography (CCC) processes differ in the volumes of the loaded solution of components to be separated and in the design of the equipment. Preliminary mathematical modeling is necessary for selection of the optimal design and operation mode of these CCC separations. This study aims to compare simulations of CCC separations at different scales, using an exact description based on the model of equilibrium cells and a much simpler approximate solution based on the Gaussian distribution. Equations for modeling CCC separations of different scales and examples of simulation these separations are presented. It is shown that the discrepancy between the two simulations increases with an increase in the volume of the loaded solution of the components and a decrease in the number of equilibrium cells of a CCC device. In analytical and preparative separations, which are based on complex centrifugal devices, and relatively small sample volumes are injected, approximate equations can be used to simulate various options of CCC separation. In industrial-scale CCC separations, large volumes of the solution of components may be loaded, and as we have proposed previously, these separations can be based on a cascade of mixer-settler extractors. In this case, a more accurate mathematical description based on the cell model equations should be used for modeling.

BORS/BJR TRAVELLING FELLOWSHIP: IMAGE-DRIVEN SUBJECT-SPECIFIC SPINE MODELS: DEVELOPING A NOVEL TOOL TO MEASURE IN VIVO LOADING

AbstractObjectivesSpinal disorders such as back pain incur a substantial societal and economic burden. Unfortunately, there is lack of understanding and treatment of these disorders are further impeded by the inability to assess spinal forces in vivo. The aim of this project is to address this challenge by developing and testing a novel image-driven approach that will assess the forces in an individual's spine in vivo by incorporating information acquired from multimodal imaging (magnetic resonance imaging (MRI) and biplane X-rays) in a subject-specific model.MethodsMagnetic resonance and biplane X-ray imaging are used to capture information about the anatomy, tissues, and motion of an individual's spine as they perform a range of everyday activities. This information is then utilised in a subject-specific computational model based on the finite element method to predict the forces in their spine. The project is also utilising novel machine learning algorithms and in vitro, six-axis mechanical testing on human, porcine and bovine samples to develop and test the modelling methods rigorously.Results & DiscussionMRI sequences have been identified that provide high-quality image data and information on different tissue types which will be used to predict subject-specific disc properties. In-vivo protocols to capture motion analysis, EMG muscle activity, and video X-rays of the spine have been designed with planned data collection of 15 healthy volunteers. Preliminary modelling work has evaluated potential machine learning approaches and quantified the sensitivity of the models developed to material properties.ConclusionThe development and testing of these image-driven subject-specific spine models will provide a new tool for determining forces in the spine. It will also provide new tools for measuring and modelling spine movement and quantifying the properties of the spinal tissues.AcknowledgmentsFunding from the EPSRC: EP/V036602/1 (Meakin, Holsgrove & Javadi) and EP/V032275/1 (Holt & Williams).Declaration of Interest(b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Results of Remote Monitoring of Methane Concentration in the Air of Western Siberia Using the On-board Infrared Lidar Complex

The description of the developed infrared on-board differential absorption lidar for measuring methane content in the air was presented. The lidar was installed on board of aircraft-laboratory Tu-134 "Optic". Flight tests of the developed lidar and experimental measurements of methane concentration along the vertical routing were carried out in the summer atmosphere of mid-latitudes. Lidar measurements of methane content in the air were analyzed. They were compared with local measurements from the gas analyser installed on board of aircraftlaboratory and the results of preliminary numerical modelling. It was concluded that the on-board lidar can measure methane concentration within background values in the mid-latitude summer atmosphere.

Multi-block approach for the characterization and discrimination of Italian chickpeas landraces

An untargeted characterization was carried out to attempt the geographical discrimination of three high-valued Italian chickpeas (Cicer arietinum L.), harvested in 2019 in three traditional and relatively close production areas: Navelli (Abruzzo, Central Italy), Cicerale (Campania, South Italy), and Valentano (Lazio, Central Italy). The present study aimed to develop and validate a potentially non-destructive and routine-compatible method for the geographical traceability of chickpea landraces of high traditional value. The outer part of 146 kernels belonging to the three varieties was analysed by Attenuated Total Reflectance-Fourier Transform-Mid Infrared (ATR-FT-MIR) and FT-Near Infrared (NIR) spectroscopies. Eventually, each sample was cut in two, and the cross-sections (the internal and external parts) were analysed by the two spectroscopic techniques. Spectral information was organized in four data blocks (MIRout, MIRin, NIRout, and NIRin), and single-block Partial Least Squares-Linear Discriminant Analysis (PLS-LDA) was applied. Accurate results were obtained from the single-block-processing of the spectroscopic profiles for the outer kernel part (MIRout and NIRout) that, combined with interesting outcomes from a preliminary class modelling approach suggest the real possibility of implementing a non-destructive authentication method. Notwithstanding, Sequential and Orthogonalized (SO)-PLS-LDA and SO-Covariance selection (Covsel)-LDA were applied to interpret better the information in the four collected data blocks. In this context, VIP (Variable Importance in Projection) analysis was performed to identify the significant variables, leading to a direct chemical interpretation of the classification models.

An experimental study on the measurement of gas diffusivities in un-saturated clay based materials

Gas migration in porous media in the context of nuclear waste disposal is dominated by diffusion. The availability of abundant data on diffusion coefficients of different gases in many clay based materials such as Boom Clay, Opalinus Clay and Callovo-Oxfordian Clays provides a good overview of the rates of gas transport through these different clay rocks [1]. Such formations are being considered as potential host rocks for the disposal of high and intermediate level radioactive wastes across Europe. Diffusion coefficients have been studied with particular interest due to the unavoidable gas generation phase in the nuclear waste repository [2]. However, all the diffusion measurements performed so far have been under fully saturated conditions, with little experimental data on gas diffusivities in partially saturated conditions, which have been hypothesized to exist during the early part of the life cycle of the repository [3]. The objective of the current study is to provide an overview of the effect of desaturation on the rate of diffusive transport of gases in partially saturated clay based materials.
 The experimental methodology is based on the double through diffusion setup used in previous studies to measure gas diffusivities in saturated clays [1]. However, the setup is modified so as to keep a fixed level of unsaturation in the clay sample. This is done by employing the vapour equilibrium technique, using oversaturated salt solutions in both upstream and downstream reservoirs to maintain a constant relative humidity in the entire setup [4].
 Preliminary pore network modelling has already shown that the gas diffusivity increases with a decrease in water saturation of the clay material. However, the predicted trend also suggests that this increase is only marginal and should not normally exceed an order of magnitude. This is shown in the figure below.
 All the diffusion measurements are carried out on synthetic clay samples of dimensions 3.8 cm (diameter) and 2 cm (height). In Table 1, the Sw stands for water saturation. The compositions of the synthetic clay samples (60% clay, 20% sand, 20% silt) have been adjusted so as to most closely mimic the mineralogical compostion of Boom Clay. Synthetic samples are used instead of natural samples like Boom Clay because of their better physical response to drying than Boom Clay.
 The selected control variable to lower the saturation of the material is suction, which is imposed by changing the relative humidity of the environment using oversaturated salt solutions [4]. Suction can be kept constant given constant ambient temperature and pressure. Thus, the clay sample is conditioned at a certain suction, which in turn leads to desaturation in the range of 70-100% of total saturation depending on the level of suction. For this study, the saturation range has been fixed in between 70-100% of total saturation. This range has been chosen because of what is expected in a real life nuclear waste repository. The first measured diffusion coefficients in two partially saturated samples are shown in Table 1. The initial measurements of gas diffusion coefficients in unsaturated synthetic clays show that the increase in diffusivity of helium is higher than that of argon. Helium is the second lightest known element and has an extremely small molecular size and hence the impact of desaturation on helium diffusivity could be more pronounced than the same for heavier gases.

Design and analysis of an axial turbine for high-temperature organic Rankine cycle

The organic Rankine cycle (ORC) system is of great importance to achieving the effective exploitation of waste energy. As the essential component of the ORC system, the expander is directly related to the performance and structure size of the ORC system, which deserves to be studied in detail. A single-stage axial turbine with a U-shaped volute is presented for the high-temperature ORC system in this paper. Based on preliminary design and modeling, the turbine aerodynamic performance under design and off-design conditions is investigated in numerical simulation. Results show that the turbine efficiency is 77% with a pressure ratio of 4.78 at the design point and the turbine efficiency can still be maintained above 70% as the pressure ratio reaches 6. It can be concluded that low Reynolds number flow and negative incidence angle are the main reasons for low turbine efficiency under the low pressure ratio, while the shock wave becomes the key factor influencing turbine efficiency under the high pressure ratio. In addition, blade profile optimization and shock wave management is the primary way to maintain high turbine efficiency under a high pressure ratio. Results indicate that the turbine proposed in this paper is proven suitable for high-temperature ORC systems and the relevant research has a certain guiding value for the efficient and compact single-stage axial turbine design.

NUMERICAL MODELLING OF TSUNAMIS GENERATED BY GRANULAR LANDSLIDES IN OPENFOAM

Landslide-generated tsunamis are a relevant source of hazard for coastal areas. In this paper, the preliminary modelling results of tsunamis generated by deformable landslides by using computational fluid dynamics (CFD) methods, in OpenFOAM, is presented. The numerical approach presented here consists in modelling the granular material by using a Coulomb viscoplastic rheology. This numerical model is applied to reproduce three literature benchmark cases (2D submerged, 2D and 3D subaerial, respectively). Some preliminary qualitative and quantitative numerical results, compared to the experimental ones, are presented in the paper.

Preliminary Modeling of Coupled Motion Response for Floating Crane and Suspended Module by Using Boundary Element Approach and Empirical Model

Preliminary Modeling of Coupled Motion Response for Floating Crane and Suspended Module by Using Boundary Element Approach and Empirical Model

Analysisof Riskof Self-Ignition Grain Products During Storage

The paper analyzes the risk of spontaneous combustion of grain products during storage. It has been established that there is an annual increase in the number of fires at grain elevators. The article presents a method for early detection of a fire hazardous state of a grain embankment, in which, by means of preliminary laboratory modeling, the construction of experimental dependences of the temperature of a grain embankment on time is provided. It is shown that due to this, the accuracy of predicting the critical characteristics of a grain embankment increases. It has been experimentally proved that preliminary laboratory identification of the parameters of the law of temperature change and the construction of a diagram of the dependence of the temperature of a grain embankment on time allows in production conditions to determine in advance the time to reach a risky temperature value.

AAE-DSVDD: A one-class classification model for VPN traffic identification

Virtual Private Network(VPN) can provide a concealed transmission channel for communication and protect the privacy of users. However, it also brings hidden dangers to cybersecurity with its wide application. Malicious behavior or harmful information can be transmitted secretly through VPN tunnels to avoid firewall censorship. Therefore, VPN traffic identification is an important part of ensure cybersecurity. Although many efforts have been made for VPN traffic identification, existing methods mainly focus on supervised learning models. In this paper, we propose an one-class classification model called AAE-DSVDD for VPN traffic identification. First, we introduce Adversarial AutoEncoder(AAE) for preliminary modeling of VPN traffic. AAE can match the aggregated posterior distribution of the hidden layer to an arbitrary prior distribution. It associates the samples with a normal distribution in the hidden space. Secondly, We implement representation learning for VPN traffic via Deep Support Vector Data Description(DSVDD). A standardized method is designed to match the output distribution of DSVDD with the aggregated posterior distribution of AAE. It alleviates the hypersphere collapse problem of DSVDD and improves identification performance. Finally, we verify the abilities of the AAE-DSVDD model on the public dataset ISCXVPN. Compared with other one-class models, AAE-DSVDD achieved the best identification ability for VPN traffic identification. It also improves the recognition ability when identifying strange classes that are not included in the training data.

Concept Of Community-Based Tourism Development In Situ Tandon Ciater

Sustainable development must embrace the three basic principles of ecological sustainability, social and cultural sustainability, and economic sustainability for both present and future generations. The community must participate in the implementation of tourism in their area, because this involves economic, social and cultural issues of the community as well as the conservation of the nature in which they live. One of the concepts of sustainable tourism development that is oriented towards community empowerment is Community Based Tourism (CBT) which is a critical idea from conventional tourism development which often ignores rights and does not involve the community in the process. The research method used is descriptive qualitative with data collection techniques through the stages of observation, interviews and focus group discussions and documentation. Research activities consist of preliminary studies, conceptual modeling, validation and revision, and model testing. Data analysis uses an interactive analytical model from Miles and Huberman which allows data analysis when researchers are in the field or after returning from the field. This research resulted in a development concept based on community empowerment through three stages of development: (1) tourism destination development program, (2) tourism marketing development program, (3) partnership development program.

OGLE-2019-BLG-0825: Constraints on the Source System and Effect on Binary-lens Parameters Arising from a Five-day Xallarap Effect in a Candidate Planetary Microlensing Event

We present an analysis of microlensing event OGLE-2019-BLG-0825. This event was identified as a planetary candidate by preliminary modeling. We find that significant residuals from the best-fit static binary-lens model exist and a xallarap effect can fit the residuals very well and significantly improves χ 2 values. On the other hand, by including the xallarap effect in our models, we find that binary-lens parameters such as mass ratio, q, and separation, s, cannot be constrained well. However, we also find that the parameters for the source system such as the orbital period and semimajor axis are consistent between all the models we analyzed. We therefore constrain the properties of the source system better than the properties of the lens system. The source system comprises a G-type main-sequence star orbited by a brown dwarf with a period of P ∼ 5 days. This analysis is the first to demonstrate that the xallarap effect does affect binary-lens parameters in planetary events. It would not be common for the presence or absence of the xallarap effect to affect lens parameters in events with long orbital periods of the source system or events with transits to caustics, but in other cases, such as this event, the xallarap effect can affect binary-lens parameters.