Unit Size Research Articles

Development of preferred sizes for building-integrated lighting units (BILUs)

Building-Integrated Lighting Unit (BILU) is a new type of LED lighting product that is organically integrated with building elements and components. To promote the digital design, standardized production, and assembly construction of new lighting forms, it is necessary to establish Preferred Sizes (PSs) of BILU that are coordinated with building modules. With the aim of reduction in quantity and strength in universality, PSs were selected from BILU modular arrays in this paper. Based on the preliminary survey, a set of target sizes involving building, furniture, and home decoration elements was established to cover all application scenarios of PSs. Through a traversal search of feasible splicing methods of all PSs, the distribution of alternative PSs was analyzed with their universality quantified. Then, multidimensional metrics of alternative PSs were established, including the average feasible scheme proportion and feasible PS proportion of Line-BILU, as well as the feasible coverage-rate proportion and average coverage rate of Surface-BILU. A weighted Euclidean distance method was applied in the multi-criterion decision-making, realizing a quantitative optimization of PSs in multiple scenarios and under multiple objectives. A total of nineteen Line-BILU preferred sizes and sixty-five Surface-BILU preferred sizes were finally obtained, with their feasibility and advantages validated based on existing modular coordination standards and actual lighting project examples. These results can provide data support for establishing product specifications and design standards of BILUs, promote building industrialization from the lighting perspective, and stimulate the sustainable construction of architectural lighting.

A Rome district transition towards optimal and sustainable heat and power generation

In this work, a specific district of Rome energy metabolism has been studied to reduce the carbon footprint of electric and thermal energy generation. Two scenarios were investigated, one “ex-ante” with the district as it was, fully dependent on the national grid for electricity and methane-fuelled boilers for heating. And an “ex-post” scenario with the buildings retrofitted with more efficient thermal insulation, LED lights, photovoltaic panels and trigeneration systems. The energy metabolism of the district was modelled in TRNSYS in both cases. For the ex-post scenario, the digital twin implemented a control logic for energy flows with several functionalities including prioritizing the power flow, setting rules and boundaries on the operation of the co-generators, preventing batteries from overcharging/discharging. The sizing of PV panels, batteries, and cogeneration units in the ex-post scenario was optimized in terms of both energy and economic performance using a Python library with the Non-dominated Sorting Genetic algorithm (NSGA-II). In the ex-post scenario, the optimal energy system delivers significant reductions in energy costs and CO2 emissions. The energy transition results in a decrease in purchased electricity of 68.2%, CO2 emissions by 56% and generation costs by 48.9%. The Levelized Cost Of Energy (LCOE) of the district is estimated to be 196 €/MWh.

Influence of discrete laser surface melting on scuffing resistance of W6Mo5Cr4V2 steel gear

The gear transmission system is advancing towards high-speed and heavy-duty applications. Among the main failure modes of the system, tooth surface scuffing due to increased tooth surface temperature has emerged as a prominent concern in mechanical transmission. Addressing the enhancement of gear scuffing resistance has thus become an urgent challenge in this field. This paper utilized discrete laser surface melting (DLSM) treatment to create discrete laser surface melted (DLSMed) units on the surface of W6Mo5Cr4V2 steel gears, resembling the radial ribs found on the surface of Limaria basilica. The paper investigated the size, hardness, residual austenite content, and residual stress of the DLSMed units at varying current intensities and laser frequencies. Microstructural observations were conducted on the DLSMed units, followed by gear scuffing experiments performed on the Forschungsstelle für Zahnräder und Getriebebau (FZG) testing machine. The experimental findings revealed that the change in laser frequency had a clearly weaker impact on the size of the DLSMed unit compared to current intensity. The DLSMed unit consisted of two parts: the melting zone (MZ) and the heat-affected zone (HAZ), with equiaxed and dendritic microstructures, respectively. Both zones exhibited refinement with increasing current intensity and laser frequency. Moreover, the microhardness of the DLSMed unit showed significant improvement compared to that of as-received gears. The scuffing resistance of DLSMed gears was found to be closely linked to their initial surface roughness. Residual stress formation in DLSMed gears was attributed to thermal stress and microstructural stress. The distribution pattern of DLSMed units had varying effects on the scuffing load-carrying capacity of DLSMed gears. Specifically, DLSMed gears with transverse distribution of DLSMed units demonstrated a 12.5% improvement in anti-scuffing performance compared to those with longitudinal distribution. Finally, this paper elucidated the mechanism through which DLSM enhances the scuffing resistance of W6Mo5Cr4V2 steel gears.

Intrapartum fetal monitoring practices in Norway: A population-based study

ObjectiveTo describe intrapartum fetal monitoring methods used in all births in Norway in 2019–2020, assess adherence to national guidelines, investigate variation by women’s risk status, and explore associations influencing monitoring practices. MethodsA nationwide population-based study. We collected data about all pregnancies with a gestational age ≥ 22 weeks during 2019–2020 from the Medical Birth Registry of Norway. We used descriptive analyses, stratified for risk status, to examine fetal monitoring methods used in all deliveries. Univariable and multivariable logistic regression models were used to determine factors associated with monitoring with cardiotocography (CTG) in low-risk, straightforward births. ResultsIn total, 14 285 (14%) deliveries were monitored with only intermittent auscultation (IA), 46214 (46%) with only CTG, and 33417 (34%) with IA and CTG combined. Four percent (2 067/50 533) of women with risk factors were monitored with IA only. Half (10589/21 282) of the low-risk women with straightforward births were monitored with CTG. Maternal and fetal characteristics, size of the birth unit and regional practices influenced use of CTG monitoring in this group. ConclusionsMost births are monitored with CTG only, or combined with IA. Half the women with low-risk pregnancies and straightforward births were monitored with CTG although national guidelines recommending IA.

Are the size of the organizational units and the type of activities of an information technology company associated to the level of work-related stress indicators? Results of an observational study in Italy

Are the size of the organizational units and the type of activities of an information technology company associated to the level of work-related stress indicators? Results of an observational study in Italy

Applications of Multi-Objective OPF Solutions with Optimal Placement of Multiple and Multi-Type FACTS Units to IEEE System: Comparison of Different Approaches

Optimal power flow (OPF) problem and its implications for power system stability and efficiency is investigated in this study. OPF, a restricted optimization query with non-linearity and non-convexity, is one of the most challenging and fascinating problems in the recent power system. Based on these parameters, researchers have been working hard over the past few decades to identify the best solutions to the OPF issue that maintain system stability. This work presents multi-objective OPF solutions utilizing Newton's technique with numerous multi-type FACTS units. First, the GA is applied to identify the perfect size and location of the FACTS units. Next, the generator and FACTS settings are optimized. In this instance, four scenarios are taken into consideration and three OFs are employed to see how the OFs affect the positioning and dimensions of FACTS devices. The OF is suggested to consider the reduction of both generation costs and transmission losses while also optimizing the power transfer capacity of designated corridors. A full analysis relating to the IEEE-30 bus system is presented and analyzed.

Electric field emission in GdNiO3 microflower

GdNiO3 microflowers were synthesized by hydrothermal method with unit sizes of about 2.2–3.5 μm and petal sizes of ∼75–100 nm. The X-ray diffraction pattern (XRD) and Raman spectra reveal an orthorhombic crystal structure with the space group Pbnm and various Raman active vibrational modes i.e., Ag, B1 g, B2 g associated with rare earth nickelates. The total density of states (TDOS) was calculated by density functional theory (DFT) study using a hybrid functional (HSE06) and the volume of TDOS near the Fermi level confirms the semiconducting nature of GdNiO3 with band gap ∼0.688 eV. The local bulk work function (φ) was estimated theoretically at ∼5.35 eV from DFT calculations which is one of the essential parameters for the field enhancement factor (β). Field emission current density (J) vs. applied electric field (E) divulges a low turn-on field (Eto)∼4.6 V/μm@1 μA/cm2 and a threshold field (Eth)∼5.2 V/μm@10 μA/cm2 respectively. The Fowler-Nordheim (F-N) model was introduced to calculate β ∼1637 and long-term field emission current stability was observed experimentally > 4 h at the preset values of current 2 μA and 10 μA, respectively. The easy preparedness, low turn-on field, and long-term current stability without significant decay suggest this material to be an efficient electron field emitting material in the rare-earth nickelates series.

Evolution of flight control systems and aerial photography in unmanned agricultural aircraft

The advancement of UAV technologies has enabled the automated capture of photos and videos, eliminating the need for manual intervention in flight control. (Research purpose) This research aims to conduct a retrospective analysis of the evolution offlight control systems and the development of aerial photography equipment for agricultural land, covering the period from the mid-19th century to present. (Materials and methods) A systematic literature review was conducted using the historical-analytical method. The paper examines original works by both domestic and international authors, including monographs, scientific journals, conference proceedings, museum exhibitions, photographic archives, and open-source software code. (Results and discussion) The paper identifies six distinct phases in the development of aerial photography and flight control systems. The classification is based on key innovations in camera types, control systems, and aircraft designs. Each phase highlights the predominant cameras, control systems, and aircraft utilized for agricultural applications. (Conclusions) Over the past 165 years, notable changes have occurred in aerial photography parameters, including the type of photographic material, image spatial and spectral resolution, camera weight and mounting, shutter types and their mechanisms, inertial control units, integrated GPS/GLONASS receivers, and light sensors. In terms of flight control systems for UAVs, significant developments over the last 106 years include variations in flight control types, the number offlight-stabilizing sensors, obstacle detection systems, size of the flight control units, flight modes, and takeoff/landing techniques, along with interfaces for attachments. It is anticipated that future intellectualization and miniaturization of flight control systems will not only boost UAV performance but also reduce the economic costs associated with the aerial monitoring of agricultural biological assets.

Optimal Placement and sizing of DG Units Using LCA Algorithm

The motivation of this paper is to present an approach that relies on the league championship algorithm (LCA) to determine the most effective number, placement, and size of distributed generations (DG) within distribution systems. The primary objective of this approach is to minimize the losses of the power system, as well as to enhance the voltage profiles and stability index of the voltage. The optimal location of the DG units is determined through the use of the Loss Sensitivity Factor (LSF), while the optimal size of the DG units is found through the use of LCA. The IEEE 33-bus and 69-bus radial distribution systems were both tested to validate the proposed method, and the results obtained from LCA were compared to those of other methods found in the literature. The simulated results have shown that the LCA method proposed in this paper is highly effective and performs exceptionally well when addressing the problem of optimal location and sizing of DG units in radial networks.

Grid-neutral hydrogen mobility: Dynamic modelling and techno-economic assessment of a renewable-powered hydrogen plant

The seasonally varying potential to produce electricity from renewable sources such as wind, PV and hydropower is a challenge for the continuous supply of hydrogen for transport and mobility. Seasonal storage of energy allows to avoid the use of grid electricity when it is scarce; storage systems can thus increase the resilience of the energy system. For grid-neutral and renewable hydrogen production, an electrolyser is considered together with a Power-to-Gas seasonal storage system, which consists of a methanation, the gas grid as intermediate storage and a steam reformer. As feed stream, electricity from an own photovoltaic (PV) system is considered, and for some cases additional electricity from the grid or from a wind turbine. The dynamic operation of the plant during a year is simulated. It is possible to safely supply fuel cell vehicles with hydrogen from the grid-neutral plant without using electricity when it is scarce and expensive. To supply 135 kgH2/day, unit sizes of 1 MW–2.9 MW for the PV system and 0.9 MW–2.6 MW for the electrolysis are required depending on the amount of available grid-electricity. The usage of grid-electricity increases the capacity factor of the electrolysis, which results in decreased unit sizes and in a better economic performance. Seasonal storage of energy is required, which results in an increased hydrogen production in summer of approximately 50% more than directly needed by the fuel cell vehicles. The overall efficiency from electricity to hydrogen is decreased due to the storage path by 10%-points to 56% based on the higher heating value. Assuming a cost-equivalent hydrogen price per driven kilometre in comparison to the actual diesel price and electricity costs of 10 Ct/kWhel from the grid, the revenues of the system are higher than the operating costs.

Evaluation of a portable, lightweight modular system to deliver high inspired oxygen to trauma casualties without the use of pressurised cylinders

IntroductionAdministering supplemental oxygen is a standard of care for trauma casualties to minimise the deleterious effects of hypoxaemia. Forward deployment of oxygen using pressurised cylinders is challenging, for example, logistics...

Nuclear engineering and design nuclear heat supply system for a small district heating reactor

Small Modular Reactors (SMRs) are currently considered to be a potential solution for decarbonizing the district heating sector. The LUT Heat Experimental Reactor (LUTHER) is a concept for a small modular nuclear heating plant that is being designed to meet the demands of Nordic district heating networks while also incorporating high safety standards. This paper presents an extension of the work pursued by LUT University by proposing a reactor module that allows for easy scaling of unit sizes ranging from 2 MW to 120 MW. The pressure tube assembly geometry, which has been developed specifically for the LUTHER reactor module, was analyzed by modeling two significantly different-sized variants that utilize this unique structure. The modular design of LUTHER enables complete factory-assembly and the use of standard road transport for unit sizes up to 120 MW. This design prioritizes high inherent safety, targeting for siting near population centers. The proposed heating reactor concept offers a viable means of decarbonizing the district heating sector by replacing existing combustion-based production with emissions-free nuclear heat.

Carbon emissions forecasting based on temporal graph transformer-based attentional neural network

In the field of electric carbon, the mapping relationship between carbon emission flow calculation and power flow calculation was studied by combining techniques such as current trajectory tracking, carbon flow trajectory analysis, power system flow calculation methods, and electric network analysis theory. By delving into the mechanism between these two factors, a better understanding of the correlation between them can be achieved. In addition, by using time series data, graph attention neural networks (GNN), distributed computing technology, and spatiotemporal computing engines, carbon emission fluctuations can be decomposed and a high-frequency “energy-electricity-carbon” integrated dynamic emission factor can be achieved. Through the spatiotemporal distribution patterns of this dynamic factor in multiple dimensions, the carbon emissions from key industries in cities can be accurately calculated. In this paper, the LSTM-GAT model is used as the core to construct a key carbon emission prediction model for cities. The study focuses on the power plant, chemical industry, steel, transportation industry, and construction industry, which are high energy-consuming industries with an annual electricity consumption of more than 100 million kWh in a major city of China. By analyzing the entire life cycle from power generation to electricity consumption and conducting current flow analysis, monthly, weekly, and daily carbon emission calculations were performed. Additionally, other factors such as the industrial development index, GDP, coverage area of power generation enterprises, regional population, size, and type of power-consuming units were included in the comprehensive calculation to build a measurement system. By conducting experiments and analyzing historical data, we have found that the LSTM-GAT model outperforms the single models of GCN, GAT, LSTM, GRU, and RNN in terms of lower error values and higher accuracy. The LSTM-GAT model is better suited for predicting carbon emissions and related indicators with an accuracy rate of 89.5%. Our predictions show that the carbon emissions will exhibit a slow growth trend in the future, while the carbon emission intensity will decrease. This information can provide a scientific basis for government decision-making.

Fitness consequences of variation in social group size are not population‐specific but are associated with access to food in the communally breeding rodent, Octodon degus

AbstractStudies that concurrently investigate the functional benefits of group living in multiple populations of the same species are rare. Over a 3‐year period (2014–2016), we examined two ecologically contrasting populations to test multiple hypotheses for the adaptive significance of group living in the communally breeding rodent Octodon degus. We quantified the size of social units (number of adults, number of adult females), edible vegetation at burrow systems, and per capita offspring weaned (PCOW) in each population. Contrary to expectations, we did not observe population‐specific associations between group size and edible vegetation or PCOW nor universal benefits of group living. In one population, PCOW increased in mid‐sized groups with more edible vegetation. However, this trend was not consistent across years. Notably, we observed a complete reproductive failure in one population during the first year of study, one that was characterized by low rainfall and no detectable edible vegetation. This result is important because reproductive failure occurred regardless of group size, suggesting that communal living may not buffer degus against the harshest of environmental conditions. Examining how social organization shapes individual reproductive success under extreme variation in food availability is an important step towards understanding how populations will respond to a changing climate.

Modification of a commercial fish feeder for use in small rearing ponds

AbstractObjectiveAutomatic feeders are commonly used in aquaculture, but the feed delivery pattern cannot be adjusted to accommodate a variety of rearing unit sizes. For those few feeders that can be adjusted, their use has been limited because of initial costs, availability, and other issues. This paper describes modification to a commercially available fish feeder (Texas Hunter Products 31.75‐kg [70‐lb] Lake and Pond Directional Fish Feeder) to effectively provide feed to different‐sized ponds.MethodsThis feeder has a 14‐m fish feed distribution pattern, making it unusable for smaller ponds. To reduce the distance of fish feed projected from the feeder, a resistor (rheostat) was installed in series with the fan motor.ResultThe rheostat reduced the power to the fan motor, thereby decreasing the feed projection distance. In addition, because the rheostat was adjustable, the resistance—and the resulting power to the fan motor—could be easily changed, making it possible for the same feeder to be used in different‐sized ponds while using approximately the same amount of power from the battery and solar panels.ConclusionThis modification was inexpensive and relatively easy to perform. The feeders reliably dispensed feed in a number of small ponds during an 8‐month evaluation period.

Dynamic model of a power-to-gas system: Role of hydrogen storage and management strategies

Tackling climate change requires a drastic decarbonization of the energy system through the introduction of renewable energy technologies. However, a greater penetration of intermittent renewables requires large-scale flexible energy storage. This need, combined with the growing interest in the use of hydrogen in mobility and industry, makes tangible the prospect of including this energy vector in our daily lives. However, the problems related to the development of dedicated infrastructures make its positioning in the market complex. In a transition phase, power-to-gas systems constitute an emerging solution that allows the use of existing structures for natural gas and, at the same time, solves the problem of hydrogen storage. In this study, a power-to-gas system producing synthetic methane from wind energy was modeled. Management strategies for both the electrolysis system and the hydrogen storage were implemented. In particular, the impact of the storage on the mitigation of the operating condition fluctuation of the methanation unit was analyzed. To verify the influence of the sizing of the subsystems over the system performance, a sensitivity analysis on the sizes of the methanation unit and hydrogen storage was carried out. The conducted sensitivity analysis suggested selecting the smallest size of the hydrogen storage and the size of the methanation unit equal to 80% of the electrolysis system nominal production to achieve good performances of the power-to-gas system. However, the sizing of the subsystems depends on the context in which the power-to-gas system is integrated (i.e., characteristics of wind source), the possibility to valorize the hydrogen surplus (i.e., proximity to hydrogen users), and the specific objective for which the system has been designed.

Expanding Affordable Middle Housing Options in Single-Family Neighborhoods

Problem, research strategy, and findings By examining the Residential Infill Project (RIP) in Portland (OR), this study addressed the ongoing debate on single-family zoning reform, focusing on the effectiveness of legalizing middle housing in expanding housing options in single-family neighborhoods. The analysis revealed a substantial increase in the proportion of middle housing in residential developments in single-family zones, from 13.4% before the RIP implementation to 44.7% in the 2 years after RIP’s adoption. Almost 40% of these post-RIP middle housing permit units were replacements for existing homes. Compared with single-family housing developments, middle housing projects were more likely to be in neighborhoods with greater density, better walkability, and lower income. The RIP broadened middle housing accessibility by allowing their development on non-corner lots, at greater distances to the city center, and in medium-density single-family zones. The RIP’s approach to regulating development density and building size significantly reduced the average size of middle housing units in single-family zones to less than half that of single-family homes. Given the strong correlation between home sizes and prices, it seems reasonable to infer that middle housing units have become considerably more affordable since the enactment of the RIP. Takeaway for practice Eliminating single-family zoning represents an initial step in expanding housing options in single-family neighborhoods. More comprehensive zoning reforms are essential for meaningful improvements in housing affordability and diversity. Cities must reassess and amend zoning codes, particularly development standards, to foster innovation in middle housing development and encourage developers to build smaller homes to lower housing costs.

Survival of biomass and waste power generation: A global overview

Biomass and waste power generation holds the promise to secure electricity supply for a growing population and mitigate global warming simultaneously. Along with the increasing commission and installation of biomass/waste power units (BWPUs) across the globe, some BWPUs failures have been observed, including the cancellation of planned/commissioned BWPUs and the termination of those in operation before reaching their natural retirement. While empirical evidence suggests that factors like feedstock accessibility and policy instruments might affect the feasibility and performance of BWPUs, there is a lack of comprehensive investigation about why some BWPUs failed at the global scale. To fill this knowledge gap, this study quantifies the hazard ratio of BWPUs via a parametric survival analysis using a panel dataset covering a total of 12,829 BWPUs (relying on woody, non-woody, and waste biomass as raw feedstocks) located in 164 countries/regions worldwide for the period of 2001–2021. The analytical results suggest that large unit size is conducive to BWPUs failure, while feedstock accessibility and the implementation of policy instruments (including Feed-in-Tariff and carbon pricing) could largely reduce the hazard ratio of BWPUs, with varying impacts on BWPUs at the planned/commissioned stage or the operation stage, located in developed or developing countries. Our findings not only shed additional light on the fate of BWPUs, which is crucial to enriching our understanding about the development of the bioenergy sector worldwide, but also provide salient empirical evidence for policy-making in terms of ensuring feedstock accessibility, overcoming diseconomies of scale, and making fiscal instruments available and transparent to boost the confidence of investors and entrepreneurs in support of BWPUs development.

Self-similar nesting strategy enables lattices achieve dual energy-absorbing plateaus

Inspired by natural self-similar nesting (SN) strategy, the basic truss unit simple cubic (SC), face centered cubic (FCC), and body centered cubic (BCC) were regenerated into novel architected SN units, aiming to achieve dual-plateaus and improved energy-absorbing capacity compared to basic truss units. Through compression experiments, finite element analysis, microstructure observation and theoretical calculation, the SN lattices were investigated to explore the influence of the nesting ratio on the compressive responses. The optimal nesting ratio was verified as 0.4 for the unit size of 8 mm and the relative density of 20%, enable SN-SC and SN-FCC achieve the stable and excellent energy absorption capabilities. Furthermore, the underlying mechanism of dual-plateau achieved by SN strategy was revealed that a SN unit can be zoned into a stronger region containing the nested core SC/FCC and a weaker region consisting of exterior nest SC/FCC and mediation BCC. The higher yield strength of the nested core SC/FCC compared to the exterior nest SC/FCC and BCC actually cause the second higher stress plateau and the better failure-resistance for the SN lattices. The improvement effect of SN strategy on SC and FCC units indicates that SN strategy has the potential to be applicable to various strut-based units.

Storm damage assessment of a port in the Southwestern Black Sea

This paper presents a comprehensive investigation of the storm damage at a commercial port located in the Southwestern Black Sea Region that occurred on January 18–19, 2018. One week after the event, a field survey was conducted at the port focusing on significantly damaged mound breakwaters and protection structures that failed at several sections. A numerical wave modeling study is carried out to estimate the wave characteristics at deep sea, nearshore, and inside the port to assess the observed damage during the field survey. Widely used numerical models WAVEWATCH III, SWAN, and SWASH are utilized using nested computational domains and calibrated based on satellite measurements. As a result, the significant wave height of the storm is estimated as 7.8 m with a peak period of 12.4 s near the port area, approaching mainly from the northwest direction. The damage mechanisms of the mound structures are discussed based on the field observations and the wave modeling studies. The insufficient seaside armor unit sizes and the orientation of the breakwaters are found to be the main reasons for the damage.