Reference Conditions Research Articles

Analysis of changes in temperature and precipitation in South American countries and ecoregions: comparison between reference conditions and three representative concentration pathways for 2050

Analysis of changes in temperature and precipitation in South American countries and ecoregions: comparison between reference conditions and three representative concentration pathways for 2050

IPEM code of practice for proton therapy dosimetry based on the NPL primary standard proton calorimeter calibration service.

Internationally, reference dosimetry for clinical proton beams largely follows the guidelines published by the International Atomic Energy Agency (IAEA TRS-398 Rev. 1, 2024). This approach yields a relative standard uncertainty of 1.7% (k=1) on the absorbed dose to water determined under reference conditions. The new IPEM code of practice presented here, enables the relative standard uncertainty on the absorbed dose to water measured under reference conditions to be reduced to 1.0% (k=1). This improvement is based on the absorbed dose to water calibration service for proton beams provided by the National Physical Laboratory (NPL), the UK's primary standards laboratory. This significantly reduced uncertainty is achieved through the use of a primary standard level graphite calorimeter to derive absorbed dose to water directly in the clinical department's beam. This eliminates the need for beam quality correction factors (k_(Q,Q_0 )) as required by the IAEA TRS-398 approach. The portable primary standard level graphite calorimeter, developed over a number of years at the NPL, is sufficiently robust to be useable in the proton beams of clinical facilities both in the UK and overseas.
The new code of practice involves performing reference dosimetry measurements directly traceable to the primary standard level graphite calorimeter in a clinical proton beam. Calibration of an ionisation chamber is performed in the centre of a standard test volume (STV) of dose, defined here to be a 10 x 10 x 10 cm volume in water, centred at a depth of 15 cm. Further STVs at reduced and increased depths are also utilised. The designated ionisation chambers are Roos-type plane-parallel chambers.
This article provides all the necessary background material, formalism, and specifications of reference conditions required to implement reference dosimetry according to this new code of practice. The Annexes provide a detailed review of ion recombination and how this should be assessed (Annex A1) and detailed work instructions for creating and delivering the standard test volumes (Annex A2).&#xD.

Energy Performance Study of a Data Center Combined Cooling System Integrated with Heat Storage and Waste Heat Recovery System

The energy efficiency of data centers has become an urgent problem as it is enjoying rapid development. This study proposes an integrated energy system involving a data center with different renewable energy sources and waste heat recovery, which can consider the partial and unsteady working load of data center. A dynamic and sophisticated system simulation model is established, which can provide both reliable and fast evaluations but also allow flexible extension of additional components. It is found that the free natural resource cooling system can cover about 28% of cooling demand. Compared to the reference condition, the proposed energy system achieves significant energy-saving benefits, with an energy-saving rate of 16.4%. The system COP increases from 3.88 to 4.64, and the PUE decreases from 1.36 to 1.30, resulting in a 23.45% reduction in electricity expenses. By integrating a waste heat recovery system, the heat pump can absorb approximately 3.57 million kWh of heat from the data center, providing approximately 4.587 million kWh of heating energy for users. The rooftop PV system generates approximately 370,000 kWh of electricity annually, covering approximately 8% of the total electricity consumption of the data center. This study can offer a new channel for the energy efficiency enhancement of data centers.

Clamping Force Estimation for Electro-Mechanical Brake Based on Friction Torque Fusion Approach

Electromechanical brakes (EMB) are anticipated to become the standard brake system in the future, gaining favor among researchers and automobile manufacturers due to their numerous advantages. However, to achieve cost competitiveness, expensive load cells used to measure the clamping force on the disc must be replaced with a clamping force estimation algorithm. To do this, an algorithm is first developed to estimate the pad contact point, which represents the point of contact between the pad and the disc, to determine where the clamping force occurs. Subsequently, this paper proposes a novel Kalman filter approach utilizing friction torque fusion for clamping force estimation. Specifically, the estimation performance is enhanced by incorporating both dynamic and static friction torque models. The proposed estimation algorithm is validated by comparing its results with the actual clamping force measured using a load cell sensor. Furthermore, experimental tests are conducted to confirm whether the proposed estimation algorithm maintains its performance under various control reference conditions, and overall, the estimation error was within about 5% in this paper.

A comparative analysis of image harmonization techniques in mitigating differences in CT acquisition and reconstruction.

The study aims to systematically characterize the effect of CT parameter variations on images and lung radiomic and deep features, and to evaluate the ability of different image harmonization methods to mitigate the observed variations. A retrospective in-house sinogram dataset of 100 low-dose chest CT scans was reconstructed by varying radiation dose (100%, 25%, 10%) and reconstruction kernels (smooth, medium, sharp). A set of image processing, convolutional neural network (CNNs), and generative adversarial network-based (GANs) methods were trained to harmonize all image conditions to a reference condition (100% dose, medium kernel). Harmonized scans were evaluated for image similarity using peak signal-to-noise ratio (PSNR), structural similarity index measure (SSIM), and learned perceptual image patch similarity (LPIPS), and for the reproducibility of radiomic and deep features using concordance correlation coefficient (CCC). CNNs consistently yielded higher image similarity metrics amongst others; for Sharp/10%, which exhibited the poorest visual similarity, PSNR increased from a mean ± CI of 17.763 ± 0.492 to 31.925 ± 0.571, SSIM from 0.219 ± 0.009 to 0.754 ± 0.017, and LPIPS decreased from 0.490 ± 0.005 to 0.275 ± 0.016. Texture-based radiomic features exhibited a greater degree of variability across conditions, i.e. a CCC of 0.500 ± 0.332, compared to intensity-based features (0.972 ± 0.045). GANs achieved the highest CCC (0.969 ± 0.009 for radiomic and 0.841 ± 0.070 for deep features) amongst others. Convolutional neural networks are suitable if downstream applications necessitate visual interpretation of images, whereas generative adversarial networks are better alternatives for generating reproducible quantitative image features needed for machine learning applications. Understanding the efficacy of harmonization in addressing multi-parameter variability is crucial for optimizing diagnostic accuracy and a critical step toward building generalizable models suitable for clinical use.

Ray Tracing of Aluminum Nitride as Anti-Reflective Coating on Silicon for Photovoltaic Devices

III-nitride materials have attracted wide interests for optoelectronic and electronic applications due to their unique and tunable semiconducting and optical properties. Aluminum nitride (AlN) exhibits an ultra-wide bandgap of 6.2[Formula: see text]eV and wide transparency window from ultraviolet to mid-infrared, making it a promising candidate as an anti-reflective coating (ARC) material on silicon for photovoltaic (PV) devices. In this work, ray tracing is utilized to investigate the optical properties of AlN ARC on 150[Formula: see text][Formula: see text]m-thick c-Si absorber. AlN with thicknesses of 60–90[Formula: see text]nm are studied and the effects towards light absorption (within 300–1200[Formula: see text]nm wavelength region) and short-circuit current density ([Formula: see text] of the solar cell are analyzed. In the ray tracing, planar c-Si absorber without an ARC is used as a reference. The reference condition exhibits weighted average reflection (WAR) of 39.8% within the 300–1200[Formula: see text]nm wavelength region with [Formula: see text] of 25.49[Formula: see text]mA/cm2. AlN with 80[Formula: see text]nm is found to be the optimum ARC thickness, which leads to the enhanced broadband absorption with WAR of 19.7% within the spectral region. This thickness represents the highest [Formula: see text] achieved in this work (35.71[Formula: see text]mA/cm[Formula: see text].

Reduction in EEG theta power as a potential marker for spatial disorientation during flight

During flight, spatial disorientation (SD) commonly occurs when a pilot’s perception conflicts with the aircraft’s actual motion, attitude, or position. A prevalent form of SD is the somatogyral illusion, which is elicited by constant speed rotation and causes a false perception of motion in the opposite direction when the rotation ceases. This research aimed to investigate changes in brain activity that occur when experiencing a somatogyral illusion by simulating conditions closely mimicking flight conditions to gain insight into how to better manage this illusion during flight. In the study, 23 volunteers were isolated from external stimuli to promote somatogyral illusion induction while seated in a Barany (rotating) chair. The study employed electroencephalogram (EEG) and eye-tracking glasses to monitor brain activity and eye movements, respectively. Participants reported their perceived motion direction using a joystick, allowing us to compare a reference condition to that of the illusion. Results indicate a significant decrease (34%) in theta power (4–7.5 Hz) over the left frontal region during the illusion, complemented by the occurrence of nystagmus in 72% of the trials. These findings align with previous studies linking SD and theta band changes, suggesting implications for EEG-based identification of SD in flight.

The effect of environmental factors on transepithelial potential in a model Amazonian teleost, the tambaqui (Colossoma macropomum): Implications for sodium balance in harsh environments.

The tambaqui (Colossoma macropomum, G. Cuvier 1818) thrives both in the ion-poor waters of the Amazon and in commercial aquaculture. In both, environmental conditions can be harsh due to low ion levels, occasional high salt challenges (in aquaculture), low pH, extreme PO2 levels (hypoxia and hyperoxia), high PCO2 levels (hypercapnia), high ammonia levels (in aquaculture), and high and low temperatures. Ion transport across the gill is affected by active transport processes, passive diffusive permeability, ion concentrations (the chemical gradient), and transepithelial potential (TEP, the electrical gradient). The latter is a very important indicator of ionoregulatory status but is rarely measured. Using normoxic, normocapnic, ion-poor, low-dissolved organic carbon (DOC) well water (27°C, pH 7.0) as the acclimation and reference condition, we first confirmed that the strongly negative TEP (-22.3 mV inside relative to the external water) is a simple diffusion potential. We then evaluated the effects on TEP of more complex waters from the Rio Negro (strong hyperpolarization) and Rio Solimões (no significant change). Additionally, we have quantified significant effects of acute, realistic changes in environmental conditions-low pH (depolarization), hypercapnia (depolarization), hypoxia (depolarization), hyperoxia (hyperpolarization), elevated NaCl concentrations (depolarization), and elevated NH4Cl concentrations (depolarization). The TEP responses help explain many of the changes in net Na+ flux rates reported in the literature. We have also shown marked effects of temperature on TEP and unidirectional Na+ flux rates (hyperpolarization and decreased fluxes at 21°C, depolarization and increased fluxes at 33°C) with no changes in net Na+ flux rates. Calculations based on the Nernst equation demonstrate the importance of the TEP changes in maintaining net Na+ balance.

Design proposal for an ionisation chamber as a secondary standard for eye lens dosimetry

We propose a system to directly measure Hp (3) quantity both in calibration conditions at laboratories and at arbitrary conditions at irradiation facilities. A commercial ionisation chamber is inserted in a spherical phantom of PMMA such that the system achieves a relatively constant response in terms of Hp (3) and matches the requirements for a secondary standard for Hp (3) quantity. The Hp (3) ionisation chamber was characterized in a dosimetry calibration laboratory under reference conditions and then, as a proof of concept, it was also tested in a work place field at an interventional cardiology department from a hospital. The design method and the measurement results are presented.

Integrating ecosystem reference conditions and vulnerability to identify ecological restoration priority areas

ABSTRACT Ecological restoration, as a component of sustainable development, can mitigate ecosystem degradation and improve ecological diversity. Accurate identification of ecological restoration priority areas (ERPAs) is essential for developing restoration practice. However, few studies have considered both ecosystem reference conditions and vulnerability during ecological restoration. In this study, a comprehensive framework of ERPA identification was developed by integrating ecosystem reference conditions and vulnerability. Using the Jialing River Basin (JRB), a representative basin of the Yangtze River, as a case study, our results revealed that under average climate conditions, the areas with high values of ecosystem reference conditions were mostly in the eastern and southeastern mountainous areas of the JRB, whereas the potential areas for ecological restoration were concentrated in the central northern and southern basin. Additionally, regions with high ecosystem vulnerability were found in the northern mountainous areas and southern urban areas and were scattered along major tributaries. Overall, the identified ERPAs were predominantly in the central northern and southern urban areas, with some scattered areas in the central basin, accounting for 9.61% of the JRB. Consequently, the JRB can be divided into four regions with targeted management strategies to address ecosystem degradation and implement restoration activities. Moreover, we suggest that the proposed framework for identifying ERPAs is used for clarifying restoration objectives, assessing the ecological baseline, and offering a scientific reference for large-scale ecological restoration efforts.

Electrode Montage for Bilateral Cervical Vestibular-Evoked Myogenic Potential Testing.

Cervical vestibular-evoked myogenic potentials (cVEMPs) are predominantly ipsilateral, myogenic responses originating from saccular activation. Some individuals have contralateral-crossed cVEMP responses with monaural air-conducted stimulation (ACS) which can contaminate cVEMP responses with bilateral stimulation. While the origin of the contralateral-crossed response is under debate, its presence has implications for cVEMP testing with midline bone conduction vibration (BCV). The purpose of this study was to determine the origin of the contralateral-crossed cVEMP response. It was hypothesized that the crossed response is due to electrode contamination and would disappear with a modified electrode montage. This is a cross-sectional research study. Fifteen healthy participants (30 ears; mean age: 27.4 19-39; 10 females). Participants completed cVEMP testing using three stimulation methods (monoaural ACS, binaural ACS, and midline BCV) and two electrode montages (sternum reference and Fp reference). In the monoaural ACS with sternum reference condition, 53.3% ears had contralateral-crossed cVEMP responses that were in-phase with the ipsilateral response for all but three ears. Whereas in the monoaural ACS with Fp reference condition, 3% had a contralateral-crossed cVEMP response. ACS and BCV cVEMP corrected amplitudes were significantly larger in the sternum reference conditions, which is attributed to artificial enhancement from the in-phase contralateral-crossed responses. The significant reduction of contralateral-crossed responses in the Fp reference condition suggests that the contralateral-crossed cVEMP response is due to reference electrode contamination and may be a more appropriate reference placement when completing cVEMPs with midline BCV.

Optimizing Type Well Construction: A New Approach for Scaling in Multiply Fractured Horizontal Wells

This paper outlines a straightforward method to standardize production histories from analog wells to common reference conditions, including average permeability in the stimulated reservoir volume, fracture half-length, stage spacing, and lateral length. The scaling technique addresses variations among analog wells in a region, crucial for constructing representative type wells and reducing uncertainty in statistical analyses. Grounded in well-established analytical solutions for constant bottom hole pressure production and transient linear flow in multiply fractured horizontal wells, the study introduces the "A-root k" analysis for estimating average fracture length and a depth of investigation equation for average permeability in the stimulated reservoir volume. Scaling involves expressing transient linear flow variables in dimensionless terms, enabling the normalization of rate-time profiles to selected reference conditions. Averaged scaled profiles yield mean, P90, P50, and P10 type wells, which can be further rescaled to design conditions for undrilled wells. The workflow, demonstrated with field examples, facilitates type well construction at desired probability levels from analog wells grouped into a few bins based on scaled production profile similarities. This approach proves effective, typically requiring one or two bins for a given resource play area.

Magnetic field quality conversion factors experimentally measured in clinical MR-linac beams for seven MR-compatible ionization chamber models.

The purpose of this work was to experimentally quantify MR-compatible ionization chamber response for 1.5T Elekta Unity and 0.35T ViewRay MRIdian MR-linac systems through the determination of the magnetic field quality conversion factor, kB,Q. Seven MR-compatible ionization chamber models from Standard Imaging and PTW were evaluated. Both the quality conversion factor kQ and the magnetic field quality conversion factor kB,Q were experimentally determined through a cross-calibration method. Specifically, the ratio of absorbed dose measured with a reference A1SL chamber under reference conditions to corrected output measured with each test chamber at the same point of measurement allowed for the determination of kB,Q. The angular dependence of the magnetic field quality conversion factor for MR-compatible chamber models was assessed for the 1.5T Elekta Unity system by measuring kB,Q with the chamber axis and magnetic field direction aligned at cardinal angles (0°, 90°, 180°, 270°). Beam quality conversion (kQ) factors for MR-compatible ionization chambers measured in a standard linac beam showed an average percent difference of -0.09±0.18% compared to computed kQ values for their conventional chamber versions. Similarly, magnetic field quality conversion (kB,Q) factors for corresponding MR and non-MR ionization chamber models measured using the same cross-calibration technique demonstrated average percent differences of -0.1±0.3% and 0.0±0.2% for the Elekta Unity and ViewRay MRIdian, respectively. Investigation of the angular dependence of this correction factor demonstrated identical chamber response for equivalent MR-compatible and conventional chamber models. This work provides critical experimental validation of MR-compatible ionization chamber performance, with a direct comparison of measured kB,Q values to corresponding conventional chamber models demonstrating nearly equivalent chamber response. kB,Q values determined using our experimental method will serve as an important reference for upcoming MR-linac reference dosimetry protocols and ultimately represent an important step towards accurate output calibration of MR-linac systems.

A Contribution to Define Indicators to Assess Sustainability

Objective: The work proposes a procedure to assess indicators related to key aspects of sustainability of organizations through an integrated procedure that includes the comparison of results and policies of various organizations to contribute to meeting the desired international requirements for sustainability. Theoretical benchmark: The literature review emphasizes that the contribution of organizations is fundamental to achieving the regional objectives of territorial development with regard to territorial planning and socio-environmental management towards sustainability. Method: The methodology used is based on bibliographic review to diagnose the current situation of organizational sustainability, characterize the models adopted by different organizations, performing benchmarking based on the results and processes to identify good sustainability practices. Results and conclusion: Based on the results of benchmarking the organization can set the methodological approach to quantify the sustainability indicators, which is best suited to their profile in relation to their activities, products and services. Implications of the research: Critical factors for organizational sustainability were identified, and one proposes a systematic approach to assess the indicators and make recommendations for corrective action and continuous improvement regarding reference condition (starting condition). Originality/value: The work contributes to clarifying what organizations need to do in practice to contribute to sustainable development.

Impacts of LULC and climate change on runoff and sediment production for the Puyango-Tumbes basin (Ecuador-Peru)

Climate change will cause alterations in the hydrological cycle, a topic of great relevance to the scientific community due to its impacts on water resources. Investigating changes in hydrological characteristics at the watershed level in the context of climate change is fundamental for developing mitigation and adaptation strategies against extreme hydrological events. This study aimed to analyze the impacts of climate change on flow and sediment production in the Puyango-Tumbes watershed. Projected climate data from CMIP6 were used, corrected through a bias adjustment process to minimize discrepancies between model data and historical observations, ensuring a more accurate representation of climate behavior. The analysis combined two representative climate change scenarios (SSP2-4.5 and SSP5-8.5) with two land use and land cover (LULC) scenarios: (a) an optimistic scenario with reduced anthropogenic effects (LULC_1985) and (b) a pessimistic scenario reflecting future impacts (LULC_2015). The SWAT model estimated future flow and sediment production for two periods (2035-2065 and 2070-2100), following model calibration and validation against the reference period 1981-2015 at three hydrometric stations: Pindo, Puyango, and El Tigre, located in Ecuador and Peru. The simulations revealed a significant increase in sediment generation under the pessimistic scenario SSP5-8.5, followed by SSP2-4.5, while lower sediment yields were observed in the optimistic scenarios. Even in the best-case scenario (optimistic SSP2-4.5), sediment yields remained substantially higher than the reference conditions. Additionally, higher flows were anticipated in some scenarios, with the El Tigre station in the lower watershed being the most affected area. These findings underscore the high probability of more frequent flooding events due to increased sediment yields and flow variability. The results highlight the urgent need for implementing adaptation measures, such as improved land use management and hydrological infrastructure, to enhance social resilience and mitigate the impacts of climate change in the watershed.

A novel 3D-printed clamping interface for the tensile testing of biological specimens

A novel 3D-printed clamping interface was designed to address challenges associated with the tensile testing of soft biological tissues, particularly specimen slippage and failure at the grips. To improve specimen adherence, four contact patterns, based on retrograde teeth, serrated, atraumatic wavy teeth, and flower patterns, were added to the interface surface. A smooth transition was considered to diminish the likelihood of transverse cutting of specimens. The 3D-printed clamping interface was produced using additive manufacturing. We performed tensile tests on porcine skin specimens considering the original serrated jaw faces (reference condition), the jaw faces with sandpaper, and the 3D-printed clamping interface with and without contact patterns. The maximum force supported by the specimens (before slippage or failure), for each test condition, was compared using statistical analysis (statistical level of p < 0.05). Compared to the reference condition (148.50 ± 31.71 N), we observed significant improvements for the 3D-printed clamping interface with the retrograde teeth (247.41 ± 31.17 N, p ≤ 0.001) and flower (220.40 ± 19.86 N, p = 0.004) contact patterns. In the reference condition, failure mostly occurred at the grips. The use of the 3D-printed clamping interface reduced the spreading of the fibers, promoting failure within the gauge section. Additionally, we observed a reduction in tissue damage at the grips for the flower and atraumatic wavy teeth conditions. In conclusion, the proposed 3D-printed clamping interface significantly improved the adherence of the porcine skin specimens while promoting failure within the gauge section. This approach can be easily customized to the available grips, has a low-cost and fast production, and uses easily accessible technology.

Effect of Refrigeration on Alzheimer’s Disease Biomarker Measurements in Plasma

AbstractBackgroundMobile phlebotomy is an attractive option for the study of Alzheimer’s disease (AD) in rural and underserved populations, but logistics of collecting, and shipping these samples outside clinical settings can introduce additional sources of variability. Knowledge is limited on the impact of field collection on blood‐based Alzheimer’s disease biomarkers, especially protein stability when dry ice is not available during shipping. Our study looks into the effects of holding plasma samples under refrigeration prior to freezing on AD biomarker concentrations compared to samples that were frozen within one hour of collection as is standard practice.MethodWe used plasma samples from 30 participants (58‐93 yo, mean age = 72.23, SD = 7.31; 18 females, 12 males) from the Wisconsin Registry for Alzheimer’s Prevention and the Wisconsin Alzheimer’s Disease Center, with aliquots from each of them undergoing three different treatments: a reference condition frozen immediately at ‐80°C, and two treatments involving refrigeration at 2‐8°C for either 48 or 72 hours before freezing. We measured the concentration of five AD blood biomarkers (ALZpath pTau217, GFAP, NfL, Aβ40, and Aβ42) using the Quanterix HD‐X platform. Finally, we evaluated biomarker stability by comparing refrigeration treatments to the aliquots frozen immediately, via repeated measures ANOVAs and ICC analysis.ResultWe found consistent concentrations of pTau217 [F(1.78, 44.49) = 0.16, p = .829; ICC(3,3) = 0.987, p &lt; 0.001], NfL [F(1.45, 39.14) = 2.84, p = .086; ICC(3,3) = 0.992, p &lt; .001], and GFAP [F(1.63, 43.89) = 1.66, p = .205; ICC(3,3) = 0.996, p &lt; 0.001] for up to 72 hours of refrigeration. However, both Aβ42 and Aβ40 levels in plasma significantly declined after refrigeration [Aβ40: F(1.22, 33.07) = 27.38, p &lt; 0.001; ICC(3,3) = 0.537, p &lt; .001; Aβ42: F(1.16, 31.34) = 15.35, p &lt; .001; ICC(3,3) = 0.713, p &lt; .001].ConclusionOur results highlight the sensitivity of plasma Ab to the storage conditions, and show pTau217, GFAP, NfL as candidates to study when ideal handling conditions for plasma samples are not easily accessible. Their resilience under refrigeration can provide flexibility to access more remote communities and increase representation in AD research.

Cumulative effects of climate change and land use on the ecological status of Scandinavian lakes show contrasted interactions in different ecoregions: the role of pre-disturbance conditions in assessing ecological status

In this study, we used subfossil chironomids to assess temporal changes in lake ecological status over the last ca. 100 years in 30 lakes spread across different ecoregions in Sweden. By comparing Benthic Quality Index values and their temporal trends, we aimed to quantify the cumulative effects of climate change and land use on lakes and unravel how their effects may vary regionally. Results indicate that land use is the overarching driver of ecological changes in impacted lakes, in line with earlier studies showing that local pressures often suppress climate change effects on freshwaters. Furthermore, the known positive co-tolerance of chironomid species to temperature and eutrophication (e.g., cold stenotherm species also being indicators of oligotrophic condition, and conversely) was anticipated to induce antagonistic effects. However, the cumulative effects of climate change and land use differ across the landscape, being synergistic in the boreal forest ecoregion and antagonistic in the mixed forest ecoregion. We suggest that the pre-disturbance conditions (i.e., species composition and pressure sensitivities) play a key role in regulating the interactions between multiple pressures in freshwaters. Overall, this finding is encouraging as it implies that restoration of lakes that focuses on the most impactful pressure (e.g., nutrient loadings from agricultural fields and urban areas) remains a plausible restoration measure despite lake warming. Results also show that the net effect of climate change on the ecological status of the reference lakes varied regionally, being more pronounced in northern lakes due to the predominance of many cold water species which are more prone to disappear in response to small variations in temperature. As reference conditions are seldom revised, it is of fundamental importance to question whether the existing reference conditions are still applicable or need to be revised due to ongoing and future climate change.

Investigation on thermal response of high temperature heat pipe under thermal mismatch conditions

As an efficient and reliable passive heat transfer equipment, high temperature heat pipes (HTHPs) plays an important role in HTHP solid state reactor system. HTHPs often encounter thermal mismatch in reactor applications, which will lead to capillary action, entrainment, and other characteristics, resulting in HTHP failure due to heat transfer limits. In this paper, the thermal response test of liquid metal HTHP under thermal mismatch conditions is studied, and the simulation test platform of HTHP mismatch is designed and built to measure the important physical parameters. The test results show that the heat transfer performance of the HTHP is the best under the condition of horizontal inclination of 60°, and the condenser power is 5.66 kW. This condition is selected as the reference condition for the transient condition test. When the HTHP experienced a transient power increase, the middle of the evaporator section, as the part with the largest heat flux of heating power, appeared a severe overheating phenomenon. The wall temperature of the evaporator section soared from 750 ℃ to 1050 ℃ in a short time, and the heating rate reached 18.9 ℃/min, which affected the smooth operation of the HTHP. When the HTHP encounters an inclination angle transient increase condition, the entrainment phenomenon is more severe, the temperature fluctuation of the condenser section is intensified, and the heat transfer of the HTHP is in an unstable state. When the HTHP encounters an inclination angle transient decrease condition, the temperature rise of the evaporator section is less than 10 ℃, the temperature at the end of the condenser section is increased, and the start-up performance of the HTHP is improved. In summary, this paper obtains the thermal response rule of HTHPs under thermal mismatch conditions through experimental research, which provides support for the safe application of HTHPs for special equipment.

Proposal for an Intelligent Methodology to Manage Energy in Buildings and Detect Anomalies as a Compass Towards Zero Energy Buildings (ZEB)

This work aims to advance the optimisation of the efficiency of thermal installations in buildings, contributing to the achievement of Zero Energy Buildings (ZEB) in the context of maintenance and operation. This is achieved through an innovative proposal that merges machine learning techniques with thermoeconomics to perform diagnoses in building thermal systems and identify cost overruns generated by intrinsic anomalies in the components and quantify their induced effects on the rest of the components. To date, the few contributions combining these techniques have been limited to industrial applications and cost calculation, without addressing their application to building thermal systems, both from a dynamic perspective and for maintenance purposes. Research using Physics-Informed Neural Networks, PINNs, in this area is even scarcer, which underlines the complexity of defining a suitable methodology. Thus, the proposal integrates PINNs with a thermoeconomic diagnosis based on characteristic curves, allowing the comparison of the current operating condition with an anomaly-free reference condition to assess the existence of anomalies and their effects. For this reason, reference models are generated for the first time with PINNs, which represents a break with the conventional maintenance approaches used by professionals in the sector. Therefore, this methodology incorporates techniques that require specialised knowledge in thermodynamic and informatics areas, which motivates the present work to be focused on the exhaustive description of the methodology and to highlight the importance of continuing to explore lines of research in this unexplored field.