Loading Period Research Articles

The effect of blade skew on the interaction tones produced by a contra-rotating unmanned aerial vehicle rotor system

This paper investigates the effect of blade skew on the interaction tones produced by a contra-rotating unmanned aerial vehicle rotor system using computational, analytical, and experimental methods. Computational fluid dynamics simulations are used to predict the periodic unsteady loading on the blades of three sets of rotors with different amounts of skew. This loading data is used to predict the acoustic pressure time-history and the sound pressure levels of the interaction tones radiated from the rotor systems. The predictions are compared with experimental measurements and show good agreement. It is observed that the amplitude of prominent interaction tones decreases as the blade skew angle increases and that the overall A-weighted sound power level of the interaction tones radiated from the rotor systems decreases significantly as skew angle increases. It is shown that this reduction in noise level is in-part caused by the de-phasing of the acoustic pressure emitted from different radii along the blades of the rotor systems.

CuO/Co3O4 materials grown directly on nickel foam for high-performance supercapacitor electrode

Electrochemical deposition and successive ionic layer adsorption and reaction (SILAR) are two widely used techniques for preparing semiconductor materials. However, there is limited research on combining the two methods to prepare CuO and Co3O4 composites for supercapacitor applications. In this study, CuO/Co3O4 semiconductor composites with spherical (S–CuO/Co3O4) and wheat spike (W–CuO/Co3O4) morphologies were prepared on nickel foam substrate using a combination of electrochemical deposition and successive ion-layer adsorption. The composites were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, and field emission scanning electron microscopy to confirm their composition and morphology. The electrochemical properties of CuO/Co3O4 materials were investigated using CV, GCD, and EIS. The results show that the load cycle has a significant impact on the performance of CuO/Co3O4, with a load period of 10 cycles exhibiting the best electrochemical performance. A comparison also reveals that the performance of the W–CuO/Co3O4 electrode is better than that of the S–CuO/Co3O4 electrode. In particular, at 1 mA/cm2 current density, the specific capacity of the W–CuO/Co3O4-10 electrode is 86.0 mAh/g, which is larger compared to S–CuO/Co3O4-10 electrode (55.8 mAh/g). After 5000 cycles of galvanostatic charge/discharge, the capacitance retention rate of the W–CuO/Co3O4-10 electrode remains 76.9 %. In addition, two water-system symmetrical supercapacitors connected in series can light up the LED for 8 min and still maintain a certain brightness. Modifying the morphology of composites has a significant impact on improving the capacitive properties of composites. This study demonstrates that the prepared CuO/Co3O4 composite material has good application potential as electrode material for supercapacitors.

The Effects of Using a Trombe Wall Modified with a Phase Change Material, from the Perspective of a Building’s Life Cycle

The increasing costs related to the use of primary energy carriers, and greater social awareness related to the need for energy saving, necessitate the use of renewable energy sources, including solar radiation. The Trombe wall (thermal storage wall—TSW) is an indirect passive solar energy system solution, aimed at obtaining, storing, and transferring thermal energy into buildings. However, there is no comprehensive information on the impact of the use of such solutions on environmental performance in the life cycle of buildings, especially those located in temperate climates. The aim of this paper is therefore to determine the environmental impact of the construction of barriers using phase change materials (PCM) from the perspective of the life cycle of a model building conforming to the current Polish energy standard (EP < 70 kWh/(m2∙yr)). The subject of the research is the structure of a TSW using phase change materials and a reference wall with a maximum overall heat transfer coefficient of 0.2 W/m2K. A comprehensive computational model of a residential building located in Rzeszów, Poland, was created, taking into account the thermal parameters of the analyzed structure of the wall and its operation under real, specific climatic conditions, as well as the environmental characteristics. High-quality input data (based on real, long-term measurements) were used to conduct a Life Cycle Assessment of the analyzed variants. As a result, the energetic and environmental efficiency of the analyzed thermal storage wall, from the perspective of the whole building’s life cycle, were assessed. According to the analyzed data, a TSW modified with paraffin enables the reduction of the energy requirements for heating by 11.3%, and the payback period of the environmental load does not exceed 1 (GWP) and 5 (IMPACT2002+) years, which were lower than the monitored period of operation.

Assessment of body resonse on integral health indicators in seafarers at sea: cohort study

OBJECTIVE. To assess the influence of sea habitat conditions on a vessel on military seamen’s health according to integral health indicators using a computer program.
 MATERIALS AND METHODS. Before going to sea and after returning to the base there were measurements of weight and body length, chest circumference, lung capacity, leading hand strength, heart rate, systolic and diastolic pressure at rest, after the load and recovery period (Martinet test) as well as blood lymphocyte content. Physical development, nutritional status, index of functional changes, the state of general non-specific adaptive response and cognitive body functions were defined; integral health assessment was held using computer programs.
 RERESULTS. Initially 66,7% had increased nutrition, after returning – 62,0%; normal status - 37,0% and 40,7%, excessive nutrition – 48,1% and 44,4%, obesity of 1st degree – 11,1% and obesity of 2nd degree – 3,7%. The proportion of seafarers with physical development above average decreased by 18,5%, adaptive response - by 7,1% (р=0,001) and body functionality - by 11,5% (р=0,006). Cognitive mental functions did not change. Standard of health decreased by 16,7% (р=0,001).
 DISCUSSION. There was confirmed negative impact of living conditions on seafarers’ health. Somatometric and physiometric indices showed negative tendencies in physical development and functionality, nonspecific adaptive body response. Stress test revealed the deterioration of aerobic capacity.
 CONCLUSION. The use of algorithm for assessing morphofunctional indicators, cognitive functions and lymphocyte content with computer processing of the results allows to evaluate the health in professional activities of seafarers.

Crankshaft High-Cycle Bending Fatigue Experiment Design Method Based on Unscented Kalman Filtering and the Theory of Crack Propagation.

The high-cycle bending fatigue experiment is one of the most important necessary steps in guiding the crankshaft manufacturing process, especially for high-power engines. In this paper, an accelerated method was proposed to shorten the time period of this experiment. First, the loading period was quickened through the prediction of the residual fatigue life based on the unscented Kalman filtering algorithm approach and the crack growth speed. Then, the accuracy of the predictions was improved obviously based on the modified training section based on the theory of fracture mechanics. Finally, the fatigue limit load analysis result was proposed based on the predicted fatigue life and the modified SAFL (statistical analysis for the fatigue limit) method. The main conclusion proposed from this paper is that compared with the conventional training sections, the modified training sections based on the theory of fracture mechanics can obviously improve the accuracy of the remaining fatigue life prediction results, which makes this approach more suitable for the application. In addition, compared with the system's inherent natural frequency, the fatigue crack can save the experiment time more effectively and thus is superior to the former factor as the failure criterion parameter.

The psychophysiology of Mastermind: Characterizing response times and blinking in a high-stakes television game show.

Television game shows have proven to be a valuable resource for studying human behavior under conditions of high stress and high stakes. However, previous work has focused mostly on choices-ignoring much of the rich visual information that is available on screen. Here, we take a first step to extracting more of this information by investigating the response times and blinking of contestants in the BBC show Mastermind. In Mastermind, contestants answer rapid-fire quiz questions while a camera slowly zooms in on their faces. By labeling contestants' behavior and blinks from 25 episodes, we asked how accuracy, response times, and blinking varied over the course of the game. For accuracy and response times, we tested whether contestants responded more accurately and more slowly after an error-exhibiting the "post-error increase in accuracy" and "post-error slowing" which has been repeatedly observed in the lab. For blinking, we tested whether blink rates varied according to the cognitive demands of the game-decreasing during periods of cognitive load, such as when pondering a response, and increasing at event boundaries in the task, such as the start of a question. In contrast to the lab, evidence for post-error changes in accuracy and response time was weak, with only marginal effects observed. In line with the lab, blinking varied over the course of the game much as we predicted. Overall, our findings demonstrate the potential of extracting dynamic signals from game shows to study the psychophysiology of behavior in the real world.

Intracortical remodelling increases in highly loaded bone after exercise cessation.

Resorption within cortices of long bones removes excess mass and damaged tissue and increases during periods of reduced mechanical loading. Returning to high-intensity exercise may place bones at risk of failure due to increased porosity caused by bone resorption. We used point-projection X-ray microscopy images of bone slices from highly loaded (metacarpal, tibia) and minimally loaded (rib) bones from 12 racehorses, 6 that died during a period of high-intensity exercise and 6 that had a period of intense exercise followed by at least 35 days of rest prior to death, and measured intracortical canal cross-sectional area (Ca.Ar) and number (N.Ca) to infer remodelling activity across sites and exercise groups. Large canals that are the consequence of bone resorption (Ca.Ar >0.04 mm2 ) were 1.4× to 18.7× greater in number and area in the third metacarpal bone from rested than exercised animals (p = 0.005-0.008), but were similar in number and area in ribs from rested and exercised animals (p = 0.575-0.688). An intermediate relationship was present in the tibia, and when large canals and smaller canals that result from partial bony infilling (Ca.Ar >0.002 mm2 ) were considered together. The mechanostat may override targeted remodelling during periods of high mechanical load by enhancing bone formation, reducing resorption and suppressing turnover. Both systems may work synergistically in rest periods to remove excess and damaged tissue.

Incidence and related factors of antiviral drug resistance in HIV-infected pregnant and postpartum women in some areas of three western provinces of China from 2017 to 2019

Objective: To analyze the incidence and related factors of drug resistance in HIV-infected pregnant and postpartum women in some areas of three western provinces of China from 2017 to 2019. Methods: From April 2017 to April 2019, face-to-face questionnaires and blood sample testing were conducted in all health care institutions providing maternal and perinatal care and midwifery-assisted services in 7 prevention of mother-to-child transmissi project areas in Xinjiang, Yunnan and Guangxi provinces/autonomous regions. Information was collected during the perinatal period and viral load, CD4+T lymphocytes and drug resistance genes were detected at the same time. The multivariate logistic regression model was used to analyze the relationship between different factors and drug resistance in HIV-infected pregnant and postpartum women. Results: A total of 655 HIV-infected pregnant and postpartum women were included in this study. The incidence of drug resistance was 3.4% (22/655), all of whom were cross-drug resistant. The rate of low, moderate and high drug resistance was 2.1% (14/655), 1.2% (8/655) and 0.8% (5/655), respectively. The drug resistance rate in the people who had previously used antiviral drugs was 1.9% (8/418), and the drug resistance rate in the people who had not used drugs was 5.9% (14/237). The NNRTI drug resistance accounted for 2.8% (18/655) and the NRTI drug resistance rate was 2.5% (16/655). The multivariate logistic regression model showed that the risk of HIV resistance was lower in pregnant women who had previously used antiviral drugs (OR=0.32, 95%CI: 0.11-0.76). Conclusion: Strengthening the management of antiviral drug use and focusing on pregnant and postpartum women who have not previously used antiviral drugs can help reduce the occurrence of drug-resistant mutations. Personalized antiviral therapy should be considered to achieve viral inhibition effects in clinical practice.

Load forecasting for regional integrated energy system based on complementary ensemble empirical mode decomposition and multi-model fusion

The multiple loads of the Regional Integrated Energy System (RIES) possess characteristics of randomness and relatively higher complexity. The current forecasting methods struggle to effectively handle the non-stationary sequence of these multiple loads, leading to less accurate load forecasting. To address this problem, this paper proposes a multi-model fusion prediction method based on Complementary Ensemble Empirical Mode Decomposition (CEEMD), Genetic Algorithm-Long Short Term Memory (GA-LSTM), Radial Basis Fusion-Autoencoder (RBF-AE), and Particle Swarm Optimization-Support Vector Machine (PSO-SVM). First, the load sequence is decomposed into different frequency Intrinsic Mode Functions (IMFs) components using CEEMD. The IMFs components are then grouped based on their zero-crossing rate and Sample Entropy (SE), resulting in three distinct groups: high-, medium-, and low-frequency components. Next, the high-frequency load component, which exhibit strong randomness, are predicted using GA-LSTM. The medium-frequency load component, which have weaker randomness, are predicted using RBF-AE. The smooth and periodic low-frequency load component are predicted using PSO-SVM. The prediction results from these three models are reconstructed to obtain the final predictive value. Finally, experimental results confirm that the forecasting model can effectively handle non-stationary load sequences and demonstrate the highest level of forecasting accuracy.

Pharmacodynamic Biomarkers in Infants with Hemophilia A Receiving Emicizumab in HAVEN 7

Background: Emicizumab, a bispecific antibody that mimics the cofactor function of activated factor (F)VIII, demonstrated a favorable safety and efficacy profile in infants with severe hemophilia A (HA) without FVIII inhibitors in HAVEN 7 (NCT04431726; Pipe et al. Blood 2022, 140[S1]: 457-459). It is known that some coagulation factors including FIX and FX, the binding targets of emicizumab, have lower plasma levels during the first 6 months of life. This research investigates whether the developing coagulation system impacts the pharmacodynamics (PD) of emicizumab prophylaxis in infants with HA enrolled to HAVEN 7 from birth to ≤ 12 months of age. Methods: Informed consent from the parents/legally authorized representative and ethics approval were obtained. PD was assessed by activated partial thromboplastin time (aPTT), FVIII activity using a chromogenic assay containing human FIX and FX (considered FVIII-like activity), and by FXIa-triggered thrombin generation (TG) assay. Plasma antigen levels of FIX and FX were determined using immunoassays. Plasma samples from 110 healthy infants (HIs; n=42, 0-3 months old; n=68, >3-24 months old) collected separately were also measured to generate age matched reference ranges. Results: In HAVEN 7, PD biomarkers, and FIX and FX plasma levels were assessed in 55 participants during the first 52 weeks of emicizumab exposure (data cut-off May 22, 2023). At baseline, mean FVIII activity was <1 IU/dL, mean TG peak height was zero, and aPTT was prolonged as expected due to the deficiency of FVIII. By the first post-baseline visit (Week 3), aPTT was normalized to the age matched reference range in most participants and was then generally maintained in the normal range throughout the treatment period. Mean (SD) FVIII-like activity increased to 22.52 (6.05) U/dL at Week 5 after the four loading doses of emicizumab and was sustained at 21-26 U/dL thereafter. Mean (SD) TG peak height increased to 67.37 (27.21) nM at Week 5 and was sustained at 67-88 nM throughout the treatment period. Mean plasma FIX and FX concentrations were not affected by emicizumab treatment. The PD biomarkers, and FIX and FX plasma levels were also analyzed as a function of age group. The loading period (first 4 weeks) was excluded and only “steady state” measurements were considered for the PD markers. All measurements were considered for FIX and FX plasma levels. Mean (SD) FVIII-like activity of 18.14 (5.40) U/dL in the youngest participants (1-2 months old) increased to 23.57 (7.64) U/dL at 3-4 months old and was similar (23-28 U/dL) in the older age groups. Age did not have a significant impact on mean TG peak height. There was no age effect on aPTT. Mean (SD) plasma FIX and FX antigen concentrations were 4.40 (1.09) µg/mL and 6.24 (1.29) µg/mL in the <1 month old participants, increased progressively with age until about 9 months old, and then stayed around 9-10 µg/mL for both FIX and FX. Lower plasma levels of FIX and FX, as well as FVIII activity were also observed in the HIs ≤3 months vs. >3 months of age. There was no significant difference in TG between ≤ 3 months vs. >3 months of age in HIs. FVIII-like activity increased with increasing emicizumab concentrations in a linear fashion up to emicizumab concentrations of 100 µg/mL. Hence, the lower FVIII-like activity in the youngest participants could be partially explained by lower mean “steady state” trough emicizumab concentrations of 48.3 µg/mL at 1 month of age, which then increased to approx. 60 µg/mL at 4-5 months of age and older. TG peak height increased with increasing emicizumab concentrations but showed large variability. Lower FIX and FX plasma levels during the first 9 months of age may also have an impact on the PD results. Even though the levels were lower in the youngest participants, increases in FVIII-like activity and TG were seen at “steady state” emicizumab in all age groups as expected based on previous studies of emicizumab. The sample sizes were small in some of the age groups analyzed. Conclusions: FVIII-like activity and thrombin generation increased, and aPTT was normalized after starting emicizumab prophylaxis in HAVEN 7. Increase with age was seen on FVIII-like activity as well as FIX and FX levels. The PD profiles of emicizumab in infants with HA were consistent with those previously observed in older children and adults with HA. Hence, even with lower levels of FIX and FX observed at the youngest participants, emicizumab showed the expected PD response.

The use of bio-oil from biodiesel production for enhancing the bitumen healing

Road pavements are exposed to traffic and temperature effects that produce distress, mainly cracking that leads to pavement failure, after which rehabilitation actions are necessary to extend pavement life. Bio-rejuvenators have been used to recover the bitumen properties lost due to fatigue of the asphalt mixtures and ageing due to temperature variations and oxidation. Thus, this paper investigates the healing of bitumen modified with bio-oil derived from biodiesel production. One base bitumen in three different ageing stages (unaged, short and long-term ageing) was used for adding up to 3% of bio-oil to the bitumen. In addition to consistency and rheological tests to characterise the modified bitumen, fatigue resistance tests with and without rest periods were performed to assess the healing through three indexes, relating the complex shear modulus, the number of cycles to failure and the amount of damage, after a rest period. It was verified that the healing follows an exponential law with the rest period, but the number of cycles in each loading period decreases compared to the previous period. For a 15-minute rest period, the healing was limited to 26.9%, but the bio-oil contributed significantly to that restoration.

In vitro study design derived from an in vivo lifting task

AbstractBiomechanical properties of the spinal tissue constituents, especially in the intervertebral disc (IVD), contribute to disability and high costs. The IVD is considered to be one of the main etiologies of chronic low back pain. Changes in the biomechanical properties of the spine, especially in the IVD, are related to multiple factors such as type and duration of loading, recovery periods, osmosis, relaxation, and diffusion processes. To quantify spinal burden in vivo, various dose models have been developed in the context of ergonomics research. In our work both in vivo and in vitro studies were conducted to investigate the effects of loading and rest periods alteration on mechanical properties of the spine. A multibody simulation (MBS) was used to translate the collected motion data from the in vivo study into forces and moments as boundary conditions for the in vitro study. An in vitro spine test rig is used to apply axial compression forces and pure moment loading in flexion/extension direction to spinal segments according to the conditions that have been determined in the MBS. In this article, an approach is presented to coordinate the boundary conditions in vivo and in vitro in order to carry out a holistic investigation. In addition, it is shown why cyclic preconditioning seems to be a more suitable preparation of the samples compared to a constant one in this experimental context.

Finite element model updating of a plate type structure made of composite material using a network of PZT

Ambient vibrations are one of the most unpredicted, undesired, and uncontrolled destructive causes of sudden failure for many types of structural systems, predominantly those made of FRP thin plates. FRP thin plates may undergo dramatic collapse beneath the periodic ambient loads associated with frequencies, particularly those approaching natural frequencies. Much research has been done over the last few decades to enhance the structural damping behaviour capabilities of thin plates against ambient vibrations via several means and systems of active vibration control. Recent, exceptional advancements in the field of smart materials and their applications in the field of active vibration control have provided a viable alternative to conventional vibration control tools (sensors/actuators). For instance, the coupled properties inherited by PWAS were utilised to develop durable, compact, and efficient actuators/sensors. To minimize the influence of the disparity between the theoretical and actual dynamic structure performances, the numerical FEM has to be updated using real structural data. In the present study, a model update of the structural parameters of a smart beam is carried out by employing PWAS as smart vibration control tools (sensor/actuator) that have been previously installed on the substrate structure. A finite element model is developed to mimic this intelligent beam. Then, laboratory experiments are undertaken to determine system parameters, which are used to update the finite element model. Finally, optimization is done to minimize the FEM variance in the designated structure vibration response from the real one.

Increasing the Production of Electrical and Thermal Energy in Biogas Plants through the Optimal Addition of Agricultural Waste

The aim of the work is to increase the yield of biogas, and, accordingly, the generation of electrical and thermal energy in biogas plants by optimally adding agricultural production waste to cattle manure. To achieve the goals set, the following tasks were solved: the yield of biogas from cattle manure was determined with the addition of various volumes of organic waste during periodic loading of the digester; on the basis of the experimental data obtained, the unimodality interval was found for the maximum yield of biogas during the fermentation of cattle pus with the addition of organic waste; Using the dichotomy method, the optimal dosage volume of various types of organic wastes into the substrate for quasi-continuous loading of the digester was calculated. Experimental studies were carried out on a biogas laboratory plant with a useful volume of 30 liters in a mesophilic mode. The most significant result is the determination, using the dichotomy method, of the optimal volumes of organate, starch, flour, whey, wastewater from wineries, crude glycerin, fuse, soap stock and molasses to manure pus to increase the biogas yield. As a result of the research, the optimal dosage formulation of various types of organic waste was substantiated to intensify the fermentation of cattle manure. The significance of the research results lies in the fact that with the optimal addition of these cosubstrates to the digester using special dispensers, the biogas yield increases from 1.4 l/h. kg of dry organic matter and above.

Mathematical model of a railroad grain cargo ridesharing service in the form of coalitions in congestion games

The object of this study is the processes of transportation of grain cargoes based on the principles of ridesharing in railroad systems without observing the traffic schedule for freight trains. In order to study the influence of the model of railroad transportation of grain based on the principles of joint use on the operation of the railroad system, it is proposed to formalize this process under the conditions of the peak load period. It is proposed to formalize the transportation of grain using the ride-sharing service in the form of coalitions in congestion games. It is proposed to turn the game setup into a nonlinear optimization problem. As part of the research, mathematical modeling of the ride-sharing service of railroad transportation of grain cargoes was carried out. Adequacy of the mathematical model was proven. It was established that compliance with the traffic schedule leads to an increase in non-productive downtime of railroad cars after loading, which reduces incentives for the formation of coalitions by shippers. However, according to the results of the simulation, under the conditions of traffic according to the schedule, taking into account the coordination of the shippers and carrier, the transportation indicators are significantly improved. This encourages shippers to form coalitions. It was found that the average duration of shipment transportation decreased by 14.9 % from the indicator according to the scenario of the current transportation model – without observing the schedule. A feature of the results within the framework of the study is that the proposed mathematical model makes it possible to adequately simulate the ride-sharing service of grain transportation in the railroad system. The field of practical application of the results is the railroad industry. The conditions for the practical application of the research results are the importance of implementing digital platforms of aggregators for the coordination of shippers and carriers. Current research will contribute to devising the improvements for grain logistics in railroad transport.

Research on the 3D Reverse Time Migration Technique for Internal Defects Imaging and Sensor Settings of Pressure Pipelines.

Although pressure pipelines serve as a secure and energy-efficient means of transporting oil, gas, and chemicals, they are susceptible to fatigue cracks over extended periods of cyclic loading due to the challenging operational conditions. Their quality and efficiency directly affect the safe operation of the project. Therefore, a thorough and precise characterization approach towards pressure pipelines can proactively mitigate safety risks and yield substantial economic and societal benefits. At present, the current mainstream 2D ultrasound imaging technology faces challenges in fully visualizing the internal defects and topography of pressure pipelines. Reverse time migration (RTM), widely employed in geophysical exploration, has the capability to visualize intricate geological structures. In this paper, we introduced the RTM into the realm of ultrasonic non-destructive testing, and proposed a 3D ultrasonic RTM imaging method for internal defects and sensor settings of pressure pipelines. To accurately simulate the extrapolation of wave field in 3D pressure pipelines, we set the absorbing boundary and double free boundary in cylindrical coordinates. Subsequently, using the 3D ultrasonic RTM approach, we attained higher-precision 3D imaging of internal defects in the pressure pipelines through suppressing imaging artifacts. By comparing and analyzing the imaging results of different sensor settings, the design of the observation system is optimized to provide a basis for the imaging and interpretation of actual data. Both simulations and actual field data demonstrate that our approach delivers top-notch 3D imaging of pipeline defects (with an imaging range accuracy up to 97.85%). This method takes into consideration the complexities of multiple scattering and mode conversions occurring at the base of the defects as well as the optimal sensor settings.

Flow and deformation due to periodic loading in a soft porous material

Soft porous materials, such as biological tissues and soils, are exposed to periodic deformations in a variety of natural and industrial contexts. The detailed flow and mechanics of these deformations have not yet been systematically investigated. Here, we fill this gap by identifying and exploring the complete parameter space associated with periodic deformations in the context of a one-dimensional model problem. We use large-deformation poroelasticity to consider a wide range of loading periods and amplitudes. We identify two distinct mechanical regimes, distinguished by whether the loading period is slow or fast relative to the characteristic poroelastic timescale. We develop analytical solutions for slow loading at any amplitude and for infinitesimal amplitude at any period. We use these analytical solutions and a full numerical solution to explore the localisation of the deformation near the permeable boundary as the period decreases and the emergence of nonlinear effects as the amplitude increases. We show that large deformations lead to asymmetry between the loading and unloading phases of each cycle in terms of the distributions of porosity and fluid flux.

A study on how efficient measures for secondary district heating system performance can be encouraged by motivational tariffs

BackgroundDistrict Heating (DH) is a technology that provides heating and domestic hot water to buildings and is an important technology for supporting the European energy transition. As such the heating systems increasingly resort to renewable heat sources and waste heat, it is even more important that they operate in the most efficient way possible. DH companies have access to the primary network of which they can impact system performance. To maximize the efficiency of the system, however, it is important that the system at the building level, known as the secondary system, is also efficient; otherwise, overall system efficiency is reduced. To increase system efficiency, return temperatures from the secondary system into the primary system have been targeted through motivational tariffs. There is limited information on how to establish a motivational tariff that motivates the customer to improve both the primary and secondary systems, which is a gap that this paper aims to fill.ResultsIn this paper, the impacts of retrofit actions in secondary systems are assessed through simulations. The identified relevant refurbishment measures to lower the return temperature to the primary system are variable flow pumps, low-temperature radiators, parallel heat exchangers, and a pass-through DHW system. Apart from simulated refurbishments, we also identify that the secondary system sometimes generates excess heat, which is valuable to recover, especially during peak load periods for the primary system. Hence, motivational tariffs targeting secondary system efficiency should also encompass an incentive for the customer to make use of waste heat in the secondary circuit to lower peak demand for the DH system.ConclusionsTo date, the most commonly used parameters introduced to customers are linked to the flow of water through the customer’s asset and the bonus malus principle. The results from simulations show that DH companies can introduce additional parameters to support customers in guiding their secondary system to perform more efficiently. Increased overall system efficiency has a positive impact on both costs and emissions.

Examination of betahistine bioavailability in combination with the monoamine oxidase B inhibitor, selegiline, in humans-a non-randomized, single-sequence, two-period titration, open label single-center phase 1 study (PK-BeST).

Betahistine was registered in Europe in the 1970s and approved in more than 80 countries as a first-line treatment for Menière's disease. It has been administered to more than 150 million patients. However, according to a Cochrane systematic review of betahistine and recent meta-analyses, there is insufficient evidence to say whether betahistine has any effect in the currently approved dosages of up to 48 mg/d. A combination with the monoamine oxidase B (MAO-B) inhibitor, selegiline, may increase the bioavailability of betahistine to levels similar to the well-established combination of L-DOPA with carbidopa or benserazide in the treatment of Parkinson's disease. We investigated the effect of selegiline on betahistine pharmacokinetics and the safety of the combination in humans. In an investigator-initiated prospective, non-randomized, single-sequence, two-period titration, open label single-center phase 1 study, 15 healthy volunteers received three single oral dosages of betahistine (24, 48, and 96 mg in this sequence with at least 2 days' washout period) without and with selegiline (5 mg/d with a loading period of 7 days). Betahistine serum concentrations were measured over a period of 240 min at eight time points (area under the curve, AUC0-240 min). This trial is registered with EudraCT (2019-002610-39) and ClinicalTrials.gov. In all three single betahistine dosages, selegiline increased the betahistine bioavailability about 80- to 100-fold. For instance, the mean (±SD) of the area under curve for betahistine 48 mg alone was 0.64 (+/-0.47) h*ng/mL and for betahistine plus selegiline 53.28 (+/-37.49) h*ng/mL. The half-life time of around 30 min was largely unaffected, except for the 24 mg betahistine dosage. In total, 14 mild adverse events were documented. This phase 1 trial shows that the MAO-B inhibitor selegiline increases betahistine bioavailability by a factor of about 80 to 100. No safety concerns were detected. Whether the increased bioavailability has an impact on the preventive treatment of Menière's disease, acute vestibular syndrome, or post-BPPV residual dizziness has to be evaluated in placebo-controlled trials. https://clinicaltrials.gov/study/NCT05938517?intr=betahistine%20and%20selegiline&rank=1, identifier: NCT05938517.

Influence of the level of compliance with preventive maintenance therapy upon the prevalence of peri-implant diseases.

A study was made to evaluate peri-implant conditions in compliers and erratic compliers with peri-implant maintenance therapy (PIMT), and to assess the role of site-specific confounders. Erratic PIMT compliers (EC) were defined as presenting attendance<2×/year, while regular compliers (RC) attended≥2×/year. Generalized estimating equations (GEE) were employed to perform a multivariable multilevel analysis in which the peri-implant condition was established as dependent variable. Overall, 86 non-smoker patients (42 RC and 44 EC) attending the Department of Periodontology of the Universitat Internacional de Catalunya were recruited consecutively on a cross-sectional basis. The mean period of loading was 9.5year. An implant placed in an erratic patient has 88% higher probability of presenting peri-implant diseases versus RC. Furthermore, the probability of diagnosis of peri-implantitis was significantly higher in EC versus RC (odds ratio [OR] 5.26; p=0.009). Among other factors, history of periodontitis, non-hygienic prosthesis, period of implant loading, and modified plaque index (mPI) at implant level were shown to significantly increase the risk of peri-implantitis diagnosis. Although not associated with peri-implantitis diagnosis risk, keratinized mucosa (KM) width, and vestibular depth (VD) were significantly associated to plaque accumulation (mPI). Compliance with PIMT was found to be significantly associated with peri-implantcondition. In this sense, attending PIMT<2×/year may be ineffective to prevent peri-implantitis.