Thermal Window Research Articles

3D-Printable Ionogels Based on Protic Ionic Liquids for Energy Applications

In light of the well-known challenges regarding the global energy economy and climate issues fuel cells are widely discussed for their benefits and potential applications in the future. One of the main problems of PEM-fuel cells is that Nafion®-membranes have a limited application temperature window of ≤ 80 °C at ambient pressure due to dehydration and corresponding loss of conductivity at higher temperatures. [1] As a result there is a significant need for new membranes of a precise and defined size and geometry exhibiting significant ion mobilities far above 100 °C.Based on their highly useful properties like thermal stability, non-flammability, and high ionic conductivities ionic liquids (ILs) are promising components in energy devices such as batteries, solar cells or fuel cells. For proper function of, for example, fuel cell membranes, it is, however, necessary to immobilize the ILs in a polymer matrix, resulting in ionogels (IGs) combining the characteristics of the respective IL with e. g. the mechanical stability of the polymer. [2] The combination of 3D-printing with suitable polymer scaffolds and suitable ILs enables the design of membrane materials with precisely controlled sizes, shapes and geometries along with the necessary electrochemical performance. [3]The aim of this work therefore is the synthesis and characterization of protic amine-based ILs for proton conduction. All compounds are ILs at room temperature. Their ionic conductivities range between 10-2 – 10-4 S/cm. Moreover, with wide electrochemical and thermal stability windows (ΔE up to 3 V, Tg around -90 °C and Td over 200 °C) these ILs are promising for ion transport in fuel cell membranes above 100 °C. The corresponding transparent and flexible IGs display promising thermal and mechanical stability and reach ionic conductivities of up to 10-3 S/cm at elevated temperatures. Moreover, this study also demonstrates that the IGs can be obtained and structured using 3D-printing; this clearly enables the design of many materials with different requirements by simply adapting the size and shape.[1] A. Martinelli, A. Matic, P. Jacobsson, L. Börjesson, A. Fernicola, S. Panero, B. Scrosati, H. Ohno, J. Phys. Chem. B, 2007, 111, 12462.[2] Y.-S. Ye, J. Rick, B.-J. Hwang, J. Mater. Chem. A, 2013, 1, 2719.[3] K. Zehbe, A. Lange, A. Taubert, Sustainable Energy Fuels, submitted.

Casting methods for the production of rotationally symmetric copper bimetals

ABSTRACT Multiple-material products are characterised by a complex property profile which is achieved by combining the particular advantages of at least two different materials. Bimetal casting is an energy- and material-efficient technology for the production of multi-metallic objects. This paper describes the development of a semi-continuous casting process for the formation of a rotationally symmetric bimetal with a cohesive bonding character at the interface of a copper–tin alloy (CuSn6) and pure copper (Cu99.5). Initial experiments are conducted by static casting to evaluate the thermal process window. Based on the results of the initial experiments, a vertical semi-continuous compound casting process is developed. A stable cohesive bond between the joining partners is accomplished by forming a solid solution at the interface. This paper is part of a Thematic Issue on Copper and its Alloys.

The roles of acclimation and behaviour in buffering climate change impacts along elevational gradients.

The vulnerability of species to climate change is jointly influenced by geographic phenotypic variation, acclimation and behavioural thermoregulation. The importance of interactions between these factors, however, remains poorly understood. We demonstrate how advances in mechanistic niche modelling can be used to integrate and assess the influence of these sources of uncertainty in forecasts of climate change impacts. We explored geographic variation in thermal tolerance (i.e. maximum and minimum thermal limits) and its potential for acclimation in juvenile European common frogs Rana temporaria along elevational gradients. Furthermore, we employed a mechanistic niche model (NicheMapR) to assess the relative contributions of phenotypic variation, acclimation and thermoregulation in determining the impacts of climate change on thermal safety margins and activity windows. Our analyses revealed that high-elevation populations had slightly wider tolerance ranges driven by increases in heat tolerance but lower potential for acclimation. Plausibly, wider thermal fluctuations at high elevations favour more tolerant but less plastic phenotypes, thus reducing the risk of encountering stressful temperatures during unpredictable extreme events. Biophysical models of thermal exposure indicated that observed phenotypic and plastic differences provide limited protection from changing climates. Indeed, the risk of reaching body temperatures beyond the species' thermal tolerance range was similar across elevations. In contrast, the ability to seek cooler retreat sites through behavioural adjustments played an essential role in buffering populations from thermal extremes predicted under climate change. Predicted climate change also altered current activity windows, but high-elevation populations were predicted to remain more temporally constrained than lowland populations. Our results demonstrate that elevational variation in thermal tolerances and acclimation capacity might be insufficient to buffer temperate amphibians from predicted climate change; instead, behavioural thermoregulation may be the only effective mechanism to avoid thermal stress under future climates.

A Cognitive-Driven Building Renovation for Improving Energy Efficiency: The Experience of the ELISIR Project

In the last few years, the technology re-evolution has deeply transformed several aspects of everyday life. For sure, one technology with a strong impact is the so-called Internet of Things (IoT). The IoT paradigm made it possible to break down the data barrier between the vertical domains on which the traditional information and communication technology (ICT) world was organized. Recently, the designers of home automation systems have begun looking to the IoT paradigm to ease the deployment of systems that are able to collect data from different plants. Such a situation has driven further evolution from the traditional automation system, where logic is defined by the programmer or by the user, to a cognitive system that is able to learn from the user’ habits regarding what should be the best configuration of plants. Several countries are funding renovations of public and private buildings for improving energy efficiency. Generally, such renovations are only focusing on the structure of the building and of its energy performance (e.g., the thermal envelope, window units, air-conditioning plants, and renewable generators) and largely ignoring the use of intelligent devices. On the contrary, scientific literature and practice have demonstrated that the wider use of IoT sensors, as well as distributed and remote intelligence, is fundamental to optimize energy consumption. This research work aimed to identify issues due the application of cognitive solutions during the renovation phase of buildings. In particular, the paper presents a cognitive architecture to support the operation and management phases of buildings, thanks to the massive digitalization of the entire supply chain of the construction sector from the single building element to the entire construction process. Such an architecture is capable of combining data from the IoT sensors and actuators of smart objects installed during the renovation phase, as well as legacy building automation systems. As an indication of the capability of the proposed solution, an intelligent window device was developed and validated. Within the Energy, Life Styled, and Seismic Innovation for Regenerated Buildings (ELISIR) project, window units are equipped with sensors to monitor indoor and outdoor condition behaviours of users. In addition, windows are able to react to changes in the environment by means of actuators that enable motorized opening and shading. Thanks to the cognitive layer designed in the project, the window is able to automatically define the best rules for opening and shading by using the local controller to satisfy user’s habits and energy efficiency targets. The cognitive layer defines the appropriate rules for opening and shading using the decision tree algorithm applied to the data generated by the sensors in order to infer users’ preferences. For this research, two prototypes of the window units were installed in two offices of Politecnico di Milano, Italy. The accuracy of this algorithm to classify the users’ behaviour and preferences was found to be around 90%, considering an observation interval of two months.

Well-defined high molecular weight polyglycolide-b-poly(L-)lactide-b-polyglycolide triblock copolymers: synthesis, characterization and microstructural analysis

Block copolymerization is already a proven technique to manipulate the properties of polymeric materials. Herein, our work presents a facile synthesis of high molecular weight polyglycolide-b-poly(L-)lactide-b-polyglycolide (b-PLLGA) triblock copolymers by ring-opening polymerization (ROP) in bulk at considerably low temperature. A series of ABA-type triblock copolymers was successfully prepared and microstructural properties were thoroughly investigated against random copolymers of poly(L-lactide-co-glycolide) (r-PLLGA). This synthesis method led to the preparation of high molecular weight b-PLLGAs with highly defined chain microstructure and an intrinsic viscosity [η] was obtained as high as 1.62 dl/g when [M]:[I] was [1]:[1000]. The investigations revealed that the prepared copolymers are in block type chain microstructure, having exclusive thermal transitions and sequence/segment properties. DSC analysis revealed that two glass (Tg) transitions and two melt transitions (Tm) exclusively associated to PGA block and PLLA block. Results were further confirmed by homosequenses of –LLLL- and -GGGG- from 13C-NMR spectroscopy. Tensile results revealed that b-PLLGA have higher tensile strength and Young’s modulus as compared to r-PLLGA. Moreover, b-PLLGAs are more thermally stable and have a wider thermal processing window.

A Thermally Induced Perovskite Crystal Control Strategy for Efficient and Photostable Wide‐Bandgap Perovskite Solar Cells

Wide‐bandgap perovskite solar cells (WBG PSCs) have gained attention as promising tandem partners for silicon solar cells due to their complementary absorption, superb open‐circuit voltage, and an easy solution process. Recently, both their performance and stability have been improved by compositional engineering or defect passivation strategies, due to the modulation of perovskite crystal size and reduction of crystal defects. Herein, a report on the thermally induced phase control (TIPC) strategy is provided, which enables efficient and photostable WBG PSCs without compositional engineering by exploring a thermal annealing process window (100–175 °C and 3–60 min) of the WBG perovskite films. Within this window, a key annealing regime is found that produces preferred crystal orientations of lead iodide and the WBG perovskite, suppressing phase segregation and reducing charge recombination in the perovskites. The WBG PSCs (composition of FA0.75MA0.15Cs0.1PbI2Br and Eg of 1.73 eV) optimized by TIPC exhibit an excellent power conversion efficiency (PCE) of 18.60% and improved operational stability, maintaining >90% of the maximum PCE (during maximum power point tracking) without encapsulation after 12 h of operation (air mass 1.5 global irradiation in ambient air conditions) or after 500 h of operation (white light‐emitting diode irradiation (100 mW cm−2) in N2 conditions).

Functional histology of the skin in the subterranean African giant mole-rat: thermal windows are determined solely by pelage characteristics.

Excavation of burrows is an extremely physically demanding activity producing a large amount of metabolic heat. Dissipation of its surplus is crucial to avoid the risk of overheating, but in subterranean mammals it is complicated due to the absence of notable body extremities and high humidity in their burrows. IR-thermography in a previous study on two species of African mole-rats revealed that body heat was dissipated mainly through the ventral body part, which is notably less furred. Here, we analyzed the dorsal and ventral skin morphology, to test if dermal characteristics could contribute to higher heat dissipation through the ventral body part. The thickness of the epidermis and dermis and the presence, extent and connectivity of fat tissue in the dermis were examined using routine histological methods, while vascular density was evaluated using fluorescent dye and confocal microscopy in the giant mole-rat Fukomys mechowii. As in other hitherto studied subterranean mammals, no subcutaneous adipose tissue was found. All examined skin characteristics were very similar for both dorsal and ventral regions: relative content of adipose tissue in the dermis (14.4 ± 3.7% dorsally and 11.0 ± 4.0% ventrally), connectivity of dermal fat (98.5 ± 2.8% and 95.5 ± 6.8%), vascular density (26.5 ± 3.3% and 22.7 ± 2.3%). Absence of large differences in measured characteristics between particular body regions indicates that the thermal windows are determined mainly by the pelage characteristics.

Designing metamaterials with quantum annealing and factorization machines

Complexity of materials designed by machine learning is currently limited by the inefficiency of classical computers. We show how quantum annealing can be incorporated into automated materials discovery and conduct a proof-of-principle study on designing complex thermofunctional metamaterials consisting of SiO2, SiC, and Poly(methyl methacrylate). Empirical computing time of our quantum-classical hybrid algorithm involving a factorization machine, a rigorous coupled wave analysis, and a D-Wave 2000Q quantum annealer was insensitive to the problem size, while a classical counterpart experienced rapid increase. Our method was used to design complex structures of wavelength selective radiators showing much better concordance with the thermal atmospheric transparency window in comparison to existing human-designed alternatives. Our result shows that quantum annealing provides scientists gigantic computational power that may change how materials are designed.

Developmental cost theory predicts thermal environment and vulnerability to global warming.

Metazoans must develop from zygotes to feeding organisms. In doing so, developing offspring consume up to 60% of the energy provided by their parent. The cost of development depends on two rates: metabolic rate, which determines the rate that energy is used; and developmental rate, which determines the length of the developmental period. Both development and metabolism are highly temperature-dependent such that developmental costs should be sensitive to the local thermal environment. Here, we develop, parameterize and test developmental cost theory, a physiologically explicit theory that reveals that ectotherms have narrow thermal windows in which developmental costs are minimized (Topt). Our developmental cost theory-derived estimates of Topt predict the natural thermal environment of 71 species across seven phyla remarkably well (R2 ~0.83). Developmental cost theory predicts that costs of development are much more sensitive to small changes in temperature than classic measures such as survival. Warming-driven changes to developmental costs are predicted to strongly affect population replenishment and developmental cost theory provides a mechanistic foundation for determining which species are most at risk. Developmental cost theory predicts that tropical aquatic species and most non-nesting terrestrial species are likely to incur the greatest increase in developmental costs from future warming.

The Neural Engine: A Reprogrammable Low Power Platform for Closed-Loop Optogenetics.

Brain-machine Interfaces (BMI) hold great potential for treating neurological disorders such as epilepsy. Technological progress is allowing for a shift from open-loop, pacemaker-class, intervention towards fully closed-loop neural control systems. Low power programmable processing systems are therefore required which can operate within the thermal window of 2° C for medical implants and maintain long battery life. In this work, we have developed a low power neural engine with an optimized set of algorithms which can operate under a power cycling domain. We have integrated our system with a custom-designed brain implant chip and demonstrated the operational applicability to the closed-loop modulating neural activities in in-vitro and in-vivo brain tissues: the local field potentials can be modulated at required central frequency ranges. Also, both a freely-moving non-human primate (24-hour) and a rodent (1-hour) in-vivo experiments were performed to show system reliable recording performance. The overall system consumes only 2.93mA during operation with a biological recording frequency 50Hz sampling rate (the lifespan is approximately 56 hours). A library of algorithms has been implemented in terms of detection, suppression and optical intervention to allow for exploratory applications in different neurological disorders. Thermal experiments demonstrated that operation creates minimal heating as well as battery performance exceeding 24 hours on a freely moving rodent. Therefore, this technology shows great capabilities for both neuroscience in-vitro/in-vivo applications and medical implantable processing units.

Metabolic responses of adult lion\u2019s paw scallops Nodipecten subnodosus exposed to acute hyperthermia in relation to seasonal reproductive effort

In marine ectotherms, reproduction is an energetically expensive process that affects their thermal window tolerance. For most species, the impacts of hyperthermia during gametogenesis have still not been addressed. Our aim was to assess the metabolic response of adult Nodipecten subnodosus scallops to thermal challenges at early development (spring) and advanced gonad maturation (summer). Scallops collected in both seasons were exposed to acute hyperthermia (26 and 30 °C, 24 h), maintaining a group of scallops at acclimation temperature (22 °C) as a control condition. During the summer, relatively low activity of hexokinase (HK), as well as low levels of ATP and GTP were found in the adductor muscle, suggesting a shift in energy investment for reproduction, although arginine phosphate (ArgP) levels were higher in summer scallops. Hyperthermia (30 °C) induced an increased energy expenditure reflected by a transitory enhanced oxygen consumption (VO2) and relatively high activities of HK and arginine kinase (AK). Moreover, a slight decrease in adenylic energy charge (AEC) was partially compensated by a decrease in ArgP. An increase in nucleotide by-products inosine monophosphate (IMP) and hypoxanthine (HX) indicated a thermal stress at 30 °C. Some of the responses to acute hyperthermia were more pronounced at advanced maturation stages (summer scallops), indicating a possible lack of energy balance, with possible implications in animals challenged to global warming scenario.

How does Spix's yellow-toothed cavy (Galea spixii Wagler, 1831) face the thermal challenges of the Brazilian tropical dry forest?

The aim of this work was to investigate the thermal biology of the Spix's yellow-toothed cavy (Galea spixii) from the hot and dry environment of the Brazilian Caatinga by infrared thermography and biophysical equations. We monitored the rectal temperature, as well as the non-evaporative (radiative and convective pathways) and evaporative heat exchanges of males and females. The mean rectal temperature of females and males was 37.58±0.02 and 37.47±0.02°C, respectively. We identified thermal windows by infrared thermography. The surface temperatures and the long-wave radiation heat exchanges were higher in the periocular, preocular, pinnae and vibrissae regions, in that order. The surface temperature of the periocular and preocular regions correlated positively with rectal temperature. Convective heat exchange was insignificant for thermoregulation by G. spixii. Evaporative heat loss increased when the thermal environment inhibited the radiative pathway. Females showed higher evaporative thermolysis than males at times of greater thermal challenge, suggesting a lower tolerance to heat stress. Therefore, infrared thermography identified the thermal windows, which represented the first line of defense against overheating in G. spixii. The periocular and preocular surface temperatures could be used as predictors of the thermal state of G. spixii.

Developmental trap or demographic bonanza? Opposing consequences of earlier phenology in a changing climate for a multivoltine butterfly.

A rapidly changing climate has the potential to interfere with the timing of environmental cues that ectothermic organisms rely on to initiate and regulate life history events. Short-lived ectotherms that exhibit plasticity in their life history could increase the number of generations per year under warming climate. If many individuals successfully complete an additional generation, the population experiences an additional opportunity to grow, and a warming climate could lead to a demographic bonanza. However, these plastic responses could become maladaptive in temperate regions, where a warmer climate could trigger a developmental pathway that cannot be completed within the growing season, referred to as a developmental trap. Here we incorporated detailed demography into commonly used photothermal models to evaluate these demographic consequences of phenological shifts due to a warming climate on the formerly widespread, multivoltine butterfly (Pieris oleracea). Using species-specific temperature- and photoperiod-sensitive vital rates, we estimated the number of generations per year and population growth rate over the set of climate conditions experienced during the past 38years. We predicted that populations in the southern portion of its range have added a fourth generation in recent years, resulting in higher annual population growth rates (demographic bonanzas). We predicted that populations in the Northeast United States have experienced developmental traps, where increases in the thermal window initially caused mortality of the final generation and reduced growth rates. These populations may recover if more growing degree days are added to the year. Our framework for incorporating detailed demography into commonly used photothermal models demonstrates the importance of using both demography and phenology to predict consequences of phenological shifts.

Thermal performance of the European flat oyster, Ostrea edulis (Linnaeus, 1758)—explaining ecological findings under climate change

Climate change challenges marine organisms by constraining their temperature-dependent scope for performance, fitness, and survival. According to the concept of Oxygen and Capacity Limited Thermal Tolerance (OCLTT), the overall thermal performance curve relates to an organism’s aerobic power budget, its overall aerobic scope for growth, exercise, reproduction, and other performances. We hypothesize that physiological principles shaping tolerance in extant ecosystems have also been operative during climatic changes in the distant past. To compare response patterns in extant fauna and their palaeo-relatives, we started here by studying the metabolic background of performance in the European flat oyster Ostrea edulis at organismic and cellular levels, focusing on the acute thermal window and the metabolic changes towards upper lethal temperatures. We investigated the response of the oysters (pre-acclimated at 12 °C) to a short-term warming protocol (by 2 °C every 48 h) from 14 to 36 °C which we identified as the lethal temperature. At the organismic level, heart and filtration rates were recorded. Gill metabolites were studied by 1H NMR spectroscopy to address thermal responses at the cellular level. Feeding activity by O. edulis (assessed by the filtration rates) was highest between 18 and 24 °C when overall energy expenditure (indicated by heart rate as a proxy for routine metabolic rate) was moderate. We conclude that this range reflects the thermal optimum of this species. Beyond 26 °C, the gill tissue of O. edulis became partly anaerobic, and cardiac dysfunction (arrhythmia) developed at 28 °C followed by an Arrhenius break point (30 °C). This mirrors performance constraints and indicates a wide temperature range of passive tolerance which may be a long-standing characteristic of ostreids supporting survival in extreme environments as well as during past and present climate oscillations.

Effect of acclimation temperature on thermoregulatory behaviour, thermal tolerance and respiratory metabolism of Lutjanus guttatus and the response of heat shock protein 70 ( Hsp70 ) and lactate dehydrogenase ( Ldh‐a ) genes

This study evaluated the effect of different environmental temperatures in the physiology of Lutjanus guttatus juveniles by analysing their thermoregulatory behaviour, thermal tolerance, oxygen consumption rates and thermal metabolic scope. Jointly, the effect of acclimation and critical temperatures on heat shock protein 70 (Hsp70) and lactate dehydrogenase (Ldh-a) gene expressions were also analysed using acclimation temperatures of 20, 23, 26, 29 and 32°C. The results showed that the final preferred temperature in juvenile snapper was 26°C with a thermal window of 336.5°C2, which was related to an optimal temperature for their physiology determined by the routine metabolic rate and thermal metabolic scope. At temperatures from 20 to 26°C, the routine metabolic rate and Hsp70 and Ldh-a genes had the lowest values related to a basal expression level. At acclimation temperatures from 29 to 32°C and after critical thermal maximum (CTmax) limit, the relative expression of Hsp70 and Ldh-a genes increased significantly, but the main response at CTmax was the upregulation of Hsp70 gene.

LCCO<sub>2</sub> AND THERMAL ENVIRONMENT OF LIVING ROOM MODEL FOR PASSIVE SOLAR HOUSE WITH THERMAL MASS

Introduction: Considering the relationship between the environmental load and the environmental quality is very important in design of the ecological housing. Moreover, the importance of study from the viewpoint of lifecycle is increasing. This study aims to clarify relations between LCCO2 and thermal environment in passive solar house with thermal mass. Method: Firstly, the settings for the model of living room with various combinations of window and thermal mass are assumed. The models are mainly based on wooden structure with the wide frontage facing south to gain solar heat. The supposed site is in suburb area of Tokyo, Japan. Three variations of the south window are set by size and position of opening and depth of eaves. Besides, four compositional variations of thermal mass to store solar heat are set by position and amount of reinforced concrete element. Consequently, the twelve models are set for following investigations. Secondly, the amount of embodied CO2 for each model is calculated by LCA tool offered by the Architectural Institute of Japan. Thirdly, the amount of operating CO2 emitted from the air-conditioning load is calculated by the Solar Designer which is a thermal environment simulation tool. Furthermore, the qualities of thermal environment focusing on the change of room temperature on sunny day in winter and summer are investigated by considering the Degree・Hour (D・H) which integrates the fluctuation of room temperature. Finally, the amount of LCCO2 is calculated by combining the embodied and operating CO2, and then, the relationships between LCCO2 and thermal environment quality by D・H are clarified. Results: 1) The model AS which has the smallest thermal mass and window indicates the smallest embodied CO2. On the other hand, the model CL which has the second largest thermal mass and the largest window shows the largest embodied CO2. These are regarded by differences for the repairing cycle of element. 2) The models of A, B and C which have larger thermal mass tend to indicate smaller operating CO2 according to reduction of window size. However, only the model D with the largest thermal mass shows a different tendency that indicates smallest operating CO2 in the case with medium window size. 3) The room temperature’s change tends to become smaller along with increase of thermal mass. However, the model DS which has largest thermal mass and smallest window shows minimum D・H in winter which is a stable environment in low temperature. 4) For the relations between LCCO2 and thermal environment, the models AS, BM, CM and DL which have different combinations of thermal mass and window size indicate smaller LCCO2 with an appropriate D・H combination in winter and summer. Especially, the model AS and DL have contrastive difference for the passive design strategy regarding with the less or more thermal mass and the smaller or larger window for solar gain, in addition to their differences for the combination of embodied CO2 and operating CO2. This result means a “trade-off” relations between LCCO2 and thermal environment and shows alternatives for design regarding the balance of thermal mass and window with proper combination of environmental load and quality.

Transparent thermal insulation silica aerogels.

Silica aerogels have received much attention due to their unique nanoporous networks, which consist of nanoscale connective silica particles and high-volume nanoscale pores. This lightweight superinsulation solid materials are synthesized by a ‘sol–gel’ process involving precursor preparation, gelation, aging and drying. By controlling their synthesis and processing, silica aerogels demonstrate good thermal and acoustic insulation, mechanical strength and optical transparency. In recent years, incorporating transparent and thermal insulation silica aerogels in energy-saving windows is of great interest for both scientific and technological applications. This review introduces the basic principles of thermal and optical properties of silica aerogels and highlights their tunability via synthetic and processing control. In addition, the use of silica aerogels in transparent thermal insulation windows is discussed.

Heat dissipation capacity influences reproductive performance in an aerial insectivore.

Climatic warming is predicted to increase the frequency of extreme weather events, which may reduce an individual's capacity for sustained activity because of thermal limits. We tested whether the risk of overheating may limit parental provisioning of an aerial insectivorous bird in population decline. For many seasonally breeding birds, parents are thought to operate close to an energetic ceiling during the 2-3 week chick-rearing period. The factors determining the ceiling remain unknown, although it may be set by an individual's capacity to dissipate body heat (the heat dissipation limitation hypothesis). Over two breeding seasons we experimentally trimmed the ventral feathers of female tree swallows (Tachycineta bicolor) to provide a thermal window. We then monitored maternal and paternal provisioning rates, nestling growth rates and fledging success. We found the effect of our experimental treatment was context dependent. Females with an enhanced capacity to dissipate heat fed their nestlings at higher rates than controls when conditions were hot, but the reverse was true under cool conditions. Control females and their mates both reduced foraging under hot conditions. In contrast, male partners of trimmed females maintained a constant feeding rate across temperatures, suggesting attempts to match the feeding rate of their partners. On average, nestlings of trimmed females were heavier than controls, but did not have a higher probability of fledging. We suggest that removal of a thermal constraint allowed females to increase provisioning rates, but additionally provided nestlings with a thermal advantage via increased heat transfer during maternal brooding. Our data provide support for the heat dissipation limitation hypothesis and suggest that depending on temperature, heat dissipation capacity can influence reproductive success in aerial insectivores.

Corrigendum to “Numerical and experimental studies on the energy performance of thermal mass windows”

Corrigendum to “Numerical and experimental studies on the energy performance of thermal mass windows”

Low-Temperature Plasma-Assisted Growth of Core–Shell GeSn Nanowires with 30% Sn

We report on the growth of Sn-catalyzed GeSn nanowires (NWs) having a GeSn core and a c-Ge shell in the presence of germane plasma at substrate temperatures (TS) below the GeSn eutectic temperature (TE), containing an exceptional Sn concentration of 30 at. % in their core. The differences between the NWs produced at TS above and below TE of the GeSn alloy are highlighted. Two types of NW growth process are identified: the previously reported in-plane solid–liquid–solid (IPSLS) process for TS ≥ TE and a plasma-assisted IPSLS (PA-IPSLS) method taking place at TS < TE; the crucial role of plasma in providing the energy necessary to melt the Sn catalyst at substrate temperatures lower than TE is discussed. The thermal activation window for each method is determined. The PA-IPSLS process is shown to provide an efficient strategy for the growth of crystalline GeSn NWs with a high Sn incorporation in a growth duration of less than 3 min.