Closed System Research Articles

SMART CADETS Prototype Design: Data-based RFID for Cadet Academic Hours Optimization Using ESP32 Microcontroller Media

This paper focuses on Palembang Aviation Polytechnic cadets as students are directed to be able to form better personalities through mental, character, and physical development. Palembang Aviation Polytechnic forms the character of cadets who are disciplined, firm, and punctual. Cadets are required to take part in 8 hours of active learning by the Palembang Aviation Polytechnic's Cadet Code of Conduct (PT3). For time efficiency and ease of monitoring cadets' compliance with compulsory education, a data-based RFID tool was designed using an Arduino as an open and close system controller when a cadet taps an RFID card. Cadets are required to tap the RFID card that each individual has to ensure that cadets arrive and leave on time during learning hours. The system will not transmit data if cadets arrive before the specified time. After that, the data will be distributed to a spreadsheet as material for assessing each cadet.

Probing the physics in the core boundary layers of the double-lined B-type binary KIC 4930889 from its gravito-inertial modes

Context. Stellar evolution models of B-type stars are still uncertain in terms of internal mixing properties, notably in the area between the convective core and the radiative envelope. This impacts age determination of such stars in addition to the computation of chemical yields produced at the end of their life. Aims. We investigated the thermal and chemical structure and rotation rate in the near-core boundary layer of the double-lined B-type binary KIC 4930889 from its four-year Kepler light curve, ground-based spectroscopy, and Gaia astrometry. Methods. We computed grids of 1D stellar structure and evolution models for different mixing profiles and prescriptions of the temperature gradient in the near-core region. We examined the preferred prescription and the near-core rotation rate using 22 prograde dipole modes detected by Kepler photometry of KIC 4930889. We employed a Mahalanobis distance merit function and considered various nested stellar model grids, rewarding goodness of fit but penalising model complexity. Results. We were able to constrain the near-core rotation rate of the pulsator to Ωrot = 0.73−0.06+0.02 d−1. Furthermore, we found a preference for either an exponentially decaying mixing profile in the near-core region or absence of additional near-core mixing, but found no preference among the various options for the temperature gradient in this region. The frequency (co)variances of our theoretical predictions are much larger than the errors on the observed frequencies. This forms the main limitation on further constraining the individual parameters of our models. A combination of spectroscopic, astrometric, binary, and asteroseismic information was used to achieve these constraints. Additionally, non-adiabatic pulsation computations of our best models indicate a need for opacity enhancements to accurately reproduce the observed mode excitation. Conclusions. The eccentric close binary system KIC 4930889 proves to be a promising target to investigate additional physics in close binaries by developing new modelling methods with the capacity to include the effect of tidal interactions for full exploitation of all detected oscillation modes.

Recovery of Phosphorus and Metals from the Ash of Sewage Sludge, Municipal Solid Waste, or Wood Biomass: A Review and Proposals for Further Use

This review provides an overview of methods to extract valuable resources from the ash fractions of sewage sludge, municipal solid waste, and wood biomass combustion. The resources addressed here include critical raw materials, such as phosphorus, base and precious metals, and rare earth elements for which it is increasingly important to tap into secondary sources in addition to the mining of primary raw materials. The extraction technologies prioritized in this review are based on recycled acids or excess renewable energy to achieve an optimum environmental profile for the extracted resources and provide benefits in the form of local industrial symbioses. The extraction methods cover all scarce and valuable chemical elements contained in the ashes above certain concentration limits. Another important part of this review is defining potential applications for the mineral residues remaining after extraction. Therefore, the aim of this review is to combine the knowledge of resource extraction technology from ashes with possible applications of mineral residues in construction and related sectors to fully close material cycle loops.

Ammonia water as a biobased fertiliser: Evaluating agronomic and environmental performance for Lactuca sativa compared to synthetic fertilisers

The European Union is actively promoting circular agriculture, aiming to reduce external inputs, close nutrient cycles, and minimise harmful emissions. This shift has spotlighted bio-based fertilisers (BBFs) as a potential substitute for energy-intensive and environmentally detrimental synthetic fertilisers. Nevertheless, research on resilience and eco-friendliness of BBFs remains limited. To address this, novel manure-derived BBF - ammonia water (AW) was examined in terms of agronomic (crop yield, nitrogen (N) fertiliser replacement value (NFRV)) and environmental (N2O, CO2, CH4, NH3) parameters in a lettuce pot cultivation. The AW had an initial alkaline pH of 11.2 (AWpHini), and another variant with pH adjusted to 5 (AWpH5) was tested for performance comparison against calcium ammonium nitrate (CAN). The agronomic efficiency was tested at three incremental N rates (30%, 60%, and 100% of crop N demand). AWpHini resulted in similar crop yield and N uptake compared to CAN for all N rates. NFRV for all N rates of AWphini exceeded 90%, however, significant reverse trend was noted for AWph5 (NFRV <90% for all rates) likely due to product's low pH affecting soil microbes. In terms of environmental performance, gaseous emissions for AWphini (52.2 CO2eq) showed significantly lower (p < 0.05) trend in comparison to CAN (120.2 CO2eq), AWph5 (114.1 CO2eq) and urea (101.3 CO2eq). The effect of acidification was observed in NH3 emissions, where AWpH5 resulted in significantly lower (p < 0.05) emissions compared to AWpHini. More research in real-world field conditions with different crops is needed to confirm ammonia water's potential as a synthetic nitrogen fertiliser replacement.

Buka Tutup Gorden Otomatis Dengan Penerapan Arudino Uno

The aim of carrying out this research is to make human work easier by using technological developments, namely the Arduino Uno, in the form of implementing an automatic curtain opening and closing system. The method used in this research is to design a program using the Arduino Uno application and design the tool, ending with testing the design results. From this research, an automatic curtain opening and closing system was produced which was controlled by the Arduino Uno program. With the development of this technology, it can make it easier for humans to control and manage without experiencing difficulties. As before, without this technology, opening and closing the curtains becomes difficult to reach because they are too high, making things uncomfortable. From this research, the output voltage from the Arduino Uno is produced with a range of 4.8 V-4.9 V.

Economic Benefits and Governance of Guiding Barrier Fishing Gear in White-Spotted Spinefoot Fish Fishing Activities (Siganus canaliculatus, Park 1797) In Bontang City Waters

Guiding barrier fishing gear has been used in recent years in the mangrove, seagrass, and coral ecosystem areas of Bontang City. In previous studies, the main target, white-spotted spinefoot fish, has depreciated and degraded as a result of overfishing. This study calculates the economic benefits and attempts to analyze the management policy of guiding barrier fishing gear to overcome the depreciation and degradation problems. To calculate the economic benefits, the fisheries production approach was used, while the policy analysis used the interpretive structural model technique. During the peak season of white-spotted spinefoot fish, the average fisherman earns up to IDR400,750 per day, with a minimum of IDR103,000 and a maximum of IDR1,904,000. The optimal fishing period is nine months, after which fishermen will stop fishing in Ramadan, August, and September. There are six guiding barrier fishing gear management policies, namely: 1) open and close systems at the installation site; 2) increase the mesh size used; 3) reduce the number; 4) moratorium on new installations; 5) limit the number of owners for each fisherman; and 6) regulate the distance between guiding barrier fishing gear. Of the six policy alternatives, the top priority is to increase the mesh size used.

A NEED ASSESSMENT OF ETHICS COURSE FOR PRIMARY CARE PHYSICIAN: PHYSICIANS' PERSPECTIVE IN YOGYAKARTA PROVINCE, INDONESIA

Background: Primary care physicians, as first-line doctors, deal with ethical cases that challenge them to make the best patient decisions. Helping primary care physicians to be more aware of ethical cases and the process of case decision-making will improve all stakeholder's needs. Physician standard opinion on the best decision for their patient will be the baseline of suited training for them.Methods: We conducted a mixed-method study to understand GP decisions regarding certain ethical cases. In the quantitative phase, we used and presented several standardized ethical cases with several "decisive" options followed by reason. For qualitative, in-depth guided interview was done with several physicians. The data was analyzed by close system coding. Results: We gained 36 responses from several physicians with 12 in-depth interviews. In the quantitative, we found that two questions related to communicating the mistake and the rural problem had the worst response, showed by highly unfavourable answers. The interview found that most physicians find it hard to decide on ethical cases, acknowledge religion as one aspect for making the decision, and expect a clear guideline that will help them make a firm decision regarding "difficult" dilemma cases. Conclusion: To avoid bad decision-making in ethical-related cases, the physician must take another training since low awareness of ethical cases will lead to unfavourable decisions regarding some dilemmas. Considering the methods and number of subjects in this research, the training should apply a specific strategy to all physicians.

Is the Direct Soil Application of Two-Phase Olive Mill Waste (Alperujo) Compatible with Soil Quality Protection?

In Spain and other Mediterranean countries, significant quantities of semi-solid olive mill waste are generated, which should be preferentially applied to agricultural soils to close nutrient cycles. However, two-phase olive mill waste (termed alperujo in Spanish) is known to pose risks to soil quality and plant production when applied to soil in large quantities. Alperujo has high contents of polyphenol substances, which can inhibit microbial growth and are also phytotoxic in nature. However, when applied in appropriate quantities and following specific methods, it is possible that the practice may not pose any risks, and this requires evaluation. As a waste management option, direct application of alperujo can supply plant nutrients and organic matter to degradation-prone Mediterranean soils. In order to validate this circular economy fertilization and soil protection strategy, an 18-month field experiment was undertaken, applying moderate quantities of alperujo on permanent crop groves throughout the Spanish region of Valencia. Eleven experimental parcels with permanent crops managed by farmers were identified to test two scenarios: a single application of 10 t/ha, and a second application of 10 t/ha after 10 months. Soil chemical parameters were assessed at 0, 6, 10, and 18 months. Soil organic carbon, total Kjeldahl nitrogen, pH, electrical conductivity, nitrates, and polyphenol contents were modified by alperujo application, but these effects were highly transient in nature, with generally no lasting effects after 4–6 months for either application scenario. Also, qualitative evaluations carried out by farmers revealed few effects, although some reductions in erosive processes and improvements in plant vigor were noted. As such, based on the measured parameters, it is concluded that the direct soil application of alperujo olive mill wastes at low application rates did not lead to any lasting detrimental effects on soil quality or compromise the productivity of permanent crops in this Mediterranean region.

Monitoring of Seasonal Under-Vine CO2 Effluxes in a Vineyard under Different Fertilization Practices

Soil CO2 efflux is a pivotal component of agro-ecosystem C budgets. It is considered a proxy indicator of biological activity and a descriptor of soil quality that is strongly linked to agricultural soil management. We investigated the effects of soil fertilization practices (organo-mineral (OMN) versus chemical (C)) on soil under-vine CO2 efflux (TSR) in an Italian rainfed vineyard (cv Chardonnay). The TSR was measured using the chamber technique as follows: a close multi-chamber system (prototype) was placed under a vine. Data (CO2, temperature, and moisture) were acquired hourly during two consecutive years (2021 and 2022) from flowering to berry ripening. Physical–hydrological soil parameters were determined, and the seasonal trends of the TSR, soil temperature, and soil moisture were assessed. The TSR measurements fluctuated for the 2021 season, ranging from 1.03 to 1.97 µmol CO2∙m−2∙s−1 for the C treatment, while for the OMN treatment, the TSR measurements ranged from 1.24 to 1.71 µmol CO2∙m−2∙s−1. Extreme weather conditions (2022) highlighted the differences between the two agronomical practices, and a decoupling was found between the TSR and the soil water content, with the TSR being controlled primarily by the soil temperature. At the daily scale, the findings showed that the TSR reached its minimum in the early morning hours (5:00–8:00). The results promote organic–mineral nutrition as an improved practice for soil carbon storage (restoration of the organic fraction) by reducing the TSR, permitting the preservation of soil quality and stabilizing the hydrological traits by preserving the biotic activities.

Modified Masses and Parallaxes of Close Binary Systems: HD 39438

We present the detailed fundamental stellar parameters of the close visual binary system HD 39438 for the first time. We used Al-Wardat’s method for analyzing binary and multiple stellar systems. The method implements Kurucz’s plane parallel model atmospheres to construct synthetic spectral energy distributions (SEDs) for both components of the system. It then combines the results of the spectroscopic analysis with the photometric analysis and compares them with the observed ones to construct the best synthetic SED for the combined system. The analysis gives the precise fundamental parameters of the individual components of the system. Based on the positions of the components of HD 39438 on the H-R diagram, and evolutionary and isochrone tracks, we found that the system belongs to the main sequence stars with masses of 1.24 and 0.98 solar masses for the components A and B, respectively, and age of 1.995 Gyr for both components. The main result of HD 39438 is new dynamical parallax, which is estimated to be 16.689 ± 0.03 mas.

Five Massive Contact Binaries with Twin Components in LMC

Massive contact binaries refer to the close binary systems in which the components have filled their respective Roche lobes and share a common envelope with early-type spectra. Twin binaries are a special type of binary system characterized by two components with nearly equal masses. The Magellanic Cloud, comprising the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud, is a fascinating galaxy that is distinct from the Milky Way. With its low metallicity, it serves as an ideal test bed for studying the formation and evolution of massive binaries and testing theoretical models. In this work, based on long-term observations with Optical Gravitational Lensing Experiment and MAssive Compact Halo Object in the LMC, we identified and performed comprehensive analyses of five massive twin contact binaries via the method of the light travel time effect and Wilson–Devinney code. The results show that all of these twin binaries are accompanied by low-mass third bodies. The third bodies have minimum masses ranging from 0.33 to 1.46 M ⊙. Their orbital periods range from 4.34 to 12.03 yr. The maximum distances between the third bodies and the central binary systems range from 6.7 to 11.4 au. Remarkably, four out of the five massive twins have evolved into deep-contact binaries, which indicates that all of them may have originated from Case A mass transfer. These results strongly suggest the significant influence of the third body in the formation and evolution of massive contact binaries and may hold the key to unraveling the origins of massive binaries.

Centrifugal Compressor Surge In Innovative Heat Pump - Part 1: Fluid Dynamic And Vibrational Analysis

Abstract In the current energy scenario, it is necessary to reduce fossil fuel consumption to achieve the far-sighted and stringent decarbonization goals. To date, heat is mainly produced through fossil fuels. Alternatively, electrically driven heat pumps can exploit renewable power to recover environmental and waste heat, offering energy efficient and environmentally friendly heating and cooling for applications ranging from domestic and commercial buildings to process industries. Centrifugal compressors are already used as prime movers of the working fluid in heat pumps, thanks to their industrial replicability, compact size, affordable costs, and good performance in terms of efficiency and low noise. However, they are subject to instabilities such as surge and stall like any other dynamic compressor and these phenomena develop quite differently than in classic open-loop systems such as gas turbines. In fact, such peculiarity is mainly due to the closed loop configuration with real gases in two-phase conditions, occurring in typical heat pump cycles. The aim of this paper is to experimentally investigate the behavior of a centrifugal compressor installed into an innovative close loop heat pump system under stable and unstable conditions from both vibrational and fluid-dynamic points of view. The impact of the main process parameters on the evolution of the instability is shown, highlighting how surge cycles change by varying system operating conditions. The experimental results shown in this paper can be a basis for the future development of validated mathematical models of closed loop heat pumps systems equipped with dynamic compressors.

Management of COVID-19 healthcare waste based on the circular economy hierarchy: A critical review.

The overall objective of this work was to conduct a critical literature review on the application of the circular economy (CE) hierarchy for the management of COVID-19 healthcare waste (HCW). To describe the problem created by COVID-19 HCW, first, the subsystems of the overall management system, including generation, segregation, classification, storage, collection, transport, treatment and disposal, were reviewed and briefly described. Then, the CE hierarchy using the 10R typology was adapted to the management of COVID-19 HCW and included the strategies Refuse, Reduce, Resell/Reuse, Repair, Reprocess, Refurbish, Remanufacture, Repurpose, Recycle and Recover (energy). Disposal was added as a sink of residues from the CE strategies. Using the detailed 10R CE hierarchy for COVID-19 HCW management is the novelty of this review. It was concluded that R-strategy selection depends on its position in the CE hierarchy and medical item criticality and value. Indicative HCW components, which can be managed by each R-strategy, were compiled, but creating value by recovering infectious downgraded materials contaminated with body fluids and tissues is not currently possible. Therefore, after applying the circular solutions, the end of pipe treatment and disposal would be necessary to close material cycles at the end of their life cycles. Addressing the risks, knowledge gaps and policy recommendations of this article may help to combat COVID-19 and future pandemics without creating environmental crises.

Structure and Chemical Composition Analysis of the Evolutionary Stages of a Primary Star with a Mass of Tipe Algol

Modeling using the STARS toolkit to analyze the structure and chemical composition of 2.24M⊙-mass Algol-type primary stars. Algol-type stars are close binary systems that experience the Algol paradox. The Algol paradox is a situation where a star with a smaller mass has evolved further than a star with a larger mass. The results of this modeling are (1) HR diagram (2) graph of stellar structure and (3) graph of stellar chemical composition as a function of radius.

CO2 Hydrogenation to CH3OH over Cu‐Based Catalysts: Primary and Side Reactions

AbstractCarbon dioxide (CO2) hydrogenation to methanol (CH3OH) is one of the most promising approaches to provide this platform chemical and to close carbon cycles. In this minireview, we systematically analyze primary and secondary reactions which can take place in this reaction over Cu‐based catalysts. In addition to repeatedly discussed reverse water gas shift reaction (RWGS) and CH3OH production directly from CO2, we consider decomposition, dehydration, dehydrogenation, and steam reforming of the desired alcohol. These reactions are usually ignored in the studies dealing with CO2 hydrogenation to CH3OH but can worsen the catalyst efficiency. Apart from the corresponding thermodynamic analysis, proposed reaction mechanisms and active sites are described and discussed. The effects of co‐fed water, CH3OH and methyl formate on catalyst performance are critically scrutinized, too. We also provide several criteria for unambiguous comparison of different catalysts in terms of CH3OH selectivity and their activity.

Visual Orbits and Alignments of Planet-hosting Binary Systems

Roughly half of Solar-type planet hosts have stellar companions, so understanding how these binary companions affect the formation and evolution of planets is an important component to understanding planetary systems overall. Measuring the dynamical properties of planet host binaries enables a valuable test of planet formation in multistar systems and requires knowledge of the binary orbital parameters. Using high-resolution imaging, we have measured the relative astrometry and visual orbits of 13 binary systems where one of the stars is known to host a transiting exoplanet. Our results indicate that the mutual inclination between the orbits of the binary hosts and the transiting planets are well aligned. Our results for close binary systems (a < 100 au) complement past work for wide planet host binaries from Gaia.

The vanishing threat: Stealthy malfunction of closed suction system

This case report presents a rare case of a mechanical ventilation leak that was initially missed by clinicians in a patient with a myxoedema coma. Despite all efforts to investigate the causes of the leak, including a bedside lung ultrasound and chest radiograph, the leak persisted. It was eventually discovered that the rhythmic inflation and deflation of the polythene covering the closed suction system was causing the leak. The closed suction system was replaced with a new one, and the tidal volume was restored, resulting in the resolution of the leak alarm. The volume leak alarm and low volume alarm are important indicators of potential problems during mechanical ventilation, and close suction system malfunction is a potential cause of volume leak that should be considered in mechanically ventilated patients. Regular monitoring and appropriate management of these alarms and potential causes can help prevent complications and optimize patient care. Keywords: Mechanical ventilation, volume leak alarm, closed suction system, and myxoedema coma.

Super-Eddington accretion as a possible scenario to form GW190425

ABSTRACT On 2019 April 25, the LIGO/Virgo Scientific Collaboration detected a compact binary coalescence, GW190425. Under the assumption of the binary neutron star (BNS), the total mass of $3.4^{+0.3}_{-0.1}\, \mathrm{M}_\odot$ lies five standard deviations away from the known Galactic population mean. In the standard common envelope scenario, the immediate progenitor of GW190425 is a close binary system composed of an NS and a He-rich star. With the detailed binary evolutionary modelling, we find that in order to reproduce GW190425-like events, super-Eddington accretion (e.g. $1,000\, \dot{M}_{\rm Edd}$) from a He-rich star onto the first-born NS with a typical mass of 1.33 M⊙ via stable Case BB mass transfer (MT) is necessarily required. Furthermore, the immediate progenitors should potentially have an initial mass of MZamsHe in a range of 3.0–3.5 M⊙ and an initial orbital period of Pinit from 0.08 d to 0.12 d, respectively. The corresponding mass accreted onto NSs via stable Case BB MT phase varies from $0.70\, \mathrm{M}_\odot$ to $0.77\, \mathrm{M}_\odot$. After the formation of the second-born NS, the BNSs are expected to be merged due to gravitational wave emission from ∼11 Myr to ∼190 Myr.

On the non-dissipative tidal evolution of the misalignment between spin and orbital angular momenta

ABSTRACT We extend our previous work on the evolution of close binary systems with misaligned orbital and spin angular momenta resulting from non-dissipative tidal interaction to include all physical effects contributing to apsidal motion. In addition to tidal distortion of the primary by the compact secondary, these include relativistic Einstein precession and the rotational distortion of the primary. The influence of the precession of the line of nodes is included. The dependence of the tidal torque on the apsidal angle $\hat{\varpi }$ couples the apsidal motion to the rate of evolution of the misalignment angle β which is found to oscillate. We provide analytical estimates for the oscillation amplitude Δβ over a wide range of parameter space confirmed by numerical integrations. This is found to be more significant near critical curves on which ${\mathrm{d}}{\hat{\varpi }} /{\mathrm{d}}t=0$ for a specified β. We find that to obtain 0.1 &amp;lt; Δβ &amp;lt; ∼1, the mass ratio q &amp;gt; ∼1, the initial eccentricity should be modest, $\cos \beta \lt 1/\sqrt{5},$ with cos β &amp;lt; 0 corresponding to retrograde rotation, initially, and the primary rotation rate should be sufficiently large. The extended discussion of apsidal motion and its coupled evolution to the misalignment angle given here has potential applications to close binaries with anomalous apsidal motion as well as transiting exoplanets such as warm Jupiters.

Search for particle acceleration in two massive Wolf–Rayet stars using uGMRT observations

ABSTRACT Large wind kinetic power of Wolf-Rayet (WR) stars make them ideal targets in low radio frequencies to search for non-thermal emission due to relativistic particle acceleration. In this paper, we present observations of two WR stars, WR 114 and WR 142, in Band 4 (550–950 MHz) and Band 5 (1050–1450 MHz) using the upgraded Giant Meterwave Radio Telescope. Neither star is detected in the observed frequency bands, nor extended emission associated with them. The upper limit to the free–free radio emission from the stellar wind enables us to constrain the mass-loss rate of WR 114 to $\lesssim \rm 10^{-5}\, M_{ \odot }\, yr^{-1}$; this is a factor three smaller than previously estimated using spectroscopic modelling. If we further assume that the WR stars are binaries, the non-detection of synchrotron emission from the putative wind collision region implies that the stars are either in very wide binary systems away from periastron, or that the stars are in close binary systems with an orbital separation &amp;lt;70 AU for WR 114 and &amp;lt;20 AU for WR 142. The non-detection of low-frequency radio emission from these two systems thus provides evidence that narrows their nature, though it does not rule them out as bona fide particle-accelerating colliding-wind binaries.