Auswahl der wissenschaftlichen Literatur zum Thema „Inflating gas“

BackgroundIn neonatal resuscitation, a ventilation device providing positive end-expiratory pressure (PEEP) is recommended. There is limited information about PEEP delivery in vivo, using different models of self-inflating bag (SIB) at different inflation rates and PEEP settings.MethodsWe compared PEEP delivery to intubated preterm lambs using four commonly available models of paired SIBs and PEEP valves, with a T-piece, with gas flow of 8 L/min. Peak inspiratory pressure inflations of 30 cmH2O, combined with set PEEP of 5, 7 and 10 cmH2O, were delivered at rates of 20, 40 and 60/min. These combinations were repeated without gas flow. We measured mean PEEP, maximum and minimum PEEP, and its difference (PEEP reduction).ResultsA total of 3288 inflations were analysed. The mean PEEP delivered by all SIBs was lower than set PEEP (P<0.001), although some differences were <0.5 cmH2O. In 55% of combinations, the presence of gas flow resulted in increased PEEP delivery (range difference 0.3–2 cmH2O). The mean PEEP was closer to set PEEP with faster inflation rates and higher set PEEPs. The mean (SD) PEEP reduction was 3.9 (1.6), 8.2 (1.8), 2 (0.6) and 1.1 (0.6) cmH2O with the four SIBs, whereas it was 0.5 (0.2) cmH2O with the T-piece.ConclusionsPEEP delivery with SIBs depends on the set PEEP, inflation rate, device model and gas flow. At recommended inflation rates of 60/min, some devices can deliver PEEP close to the set level, although the reduction in PEEP makes some SIBs potentially less effective for lung recruitment than a T-piece.

The Combibag self-inflating resuscitator incorporates an adult and a paediatric segment as well as a two-stage pressure limiting safety valve. The resuscitator is not without problems. A sizeable forward leak of gas can occur beyond the patient valve. The patient valve design is such that a spontaneously breathing patient draws his inspired gas entirely from room air. Problems can also occur with the valve either sticking or being blown forward off its seating, thereby making the resuscitator inoperable and dangerous. The use of a two-stage pressure-limiting safety valve should prevent unnecessary barotrauma but could well lead to unrecognised venting with inadequate ventilation when used by inexperienced personnel.

The effects of changing blood volume within the thoracoabdominal cavity (Vtab) have been studied in four male subjects trained in respiratory maneuvers. Subjects were studied lying supine in a pressure plethysmograph with inflatable fracture splints placed around both arms and legs. Changes in Vtab were produced by inflating the splints to 30 cmH2O. Thoracic gas volume (Vtg) measured by Boyle's law, and the change in chest wall volume (delta Vw), measured by anteroposterior magnetometers on rib cage and abdomen, were measured almost simultaneously and at two respiratory system volumes. The quantity of blood moved by splint inflation was estimated for each subject at both respiratory system volumes and varied between 215 and 752 ml. The chest wall increased 64 +/- 11.8% (mean +/- SD) of the increase in Vtab. Thus increases in thoracoabdominal blood volume increase Vw about twice the decrease in Vtg.

LED filament lamp has the characteristics of nearly 360° lighting angle, high brightness, and low energy consumption, turning it gradually into the best substitute for traditional incandescent lamps. At present, due to the limitations of heat dissipation, the development of high-power LED filament lamp is restricted. Helium is a rare gas with small density and high heat transfer coefficient. It can be used as a cooling and protective gas for LED filament lamp. In this paper, we investigated the effects of helium on the heat dissipation and luminescence performance of the A60 LED filament lamps by detecting the changes of junction temperature, color temperature, and luminous flux of different ratios helium inflating in the different power A60 LED filament lamps. Through the experiment, we found the most cost-effective ratio of helium gas in the A60 LED filament lamps without improving the lamp size and the filament diameter.

Heller, Hartmut, Gabi Fuchs, and Klaus-Dieter Schuster. Pulmonary diffusing capacities for oxygen-labeled CO2 and nitric oxide in rabbits. J. Appl. Physiol. 84(2): 606–611, 1998.—We determined the pulmonary diffusing capacity (Dl) for18O-labeled CO2(C18O2) and nitric oxide (NO) to estimate the membrane component of the respective gas conductances. Six anesthetized paralyzed rabbits were ventilated by a computerized ventilatory servo system. Single-breath maneuvers were automatically performed by inflating the lungs with gas mixtures containing 0.9% C18O2or 0.05% NO in nitrogen, with breath-holding periods ranging from 0 to 1 s for C18O2and from 2 to 8 s for NO. The alveolar partial pressures of C18O2and NO were determined by using respiratory mass spectrometry. Dl was calculated from gas exchange during inflation, breath hold, and deflation. We obtained values of 14.0 ± 1.1 and 2.2 ± 0.1 (mean value ± SD) ml ⋅ mmHg−1 ⋅ min−1for[Formula: see text]and Dl NO, respectively. The measured[Formula: see text]/Dl NOratio was one-half that of the theoretically predicted value according to Graham’s law (6.3 ± 0.5 vs. 12, respectively). Analyses of the several mechanisms influencing the determination of[Formula: see text]and Dl NOand their ratio are discussed. An underestimation of the membrane diffusing component for CO2 is considered the likely reason for the low[Formula: see text]/Dl NOratio obtained.

<b><i>Background:</i></b> Ventilation is the key intervention to resuscitate non-breathing newborns. Positive end-expiratory pressure (PEEP) may facilitate lung-liquid clearance and help establish functional residual capacity. <b><i>Objectives:</i></b> The aim of this study was to describe how mask leak and ventilation rates affect delivered PEEP and tidal volumes during newborn resuscitations using a self-inflating bag with an integrated PEEP valve. <b><i>Methods:</i></b> This was an observational study including near-term/term newborns who received bag-mask ventilation (BMV) with a new self-inflating bag with a novel 6 mbar PEEP valve, without external gas flow, between October 1, 2016 and June 30, 2018 in rural Tanzania. Helping Babies Breathe-trained midwives performed most of the resuscitations. Pressures and flow were continuously measured and recorded by resuscitation monitors. <b><i>Results:</i></b> In total, 198 newborns with a median gestation of 39 weeks (25th, 75th percentiles 37, 40) and birth weight of 3,100 g (2,580, 3,500) were included. The median delivered PEEP and expired (tidal) volume at different levels of mask leak were 6.0 mbar and 11.3 mL/kg at 0–20% mask leak, 5.5 mbar and 9.3 mL/kg at 20–40%, 5.2 mbar and 7.8 mL/kg at 40–60%, 4.6 mbar and 5.0 mL/kg at 60–80%, and 1.0 mbar and 0.6 mL/kg at 80–100% mask leak. A high ventilation rate (&#x3e;60/min) nearly halved expired volumes compared to &#x3c;60/min for 0–60% leak. The BMV rate had a negligible effect on peak inflation pressure (PIP) and PEEP. <b><i>Conclusions:</i></b> Mask leak up to 80% did not impair the provision of recommended PEEP or tidal volumes during BMV with a self-inflating bag. High or low ventilation rates did not significantly affect PIP or PEEP. Expired volumes were reduced at ventilation rates &#x3e;60/min.

The double sigmoidal nature of the mouse pressure-volume (PV) curve is well recognized but largely ignored. This study systematically examined the effect of inflating the mouse lung to 40 cm H2O transrespiratory pressure (Prs) in vivo. Adult BALB/c mice were anesthetized, tracheostomized, and mechanically ventilated. Thoracic gas volume was calculated using plethysmography and electrical stimulation of the intercostal muscles. Lung mechanics were tracked during inflation-deflation maneuvers using a modification of the forced oscillation technique. Inflation beyond 20 cm H2O caused a shift in subsequent PV curves with an increase in slope of the inflation limb and an increase in lung volume at 20 cm H2O. There was an overall decrease in tissue elastance and a fundamental change in its volume dependence. This apparent “softening” of the lung could be recovered by partial degassing of the lung or applying a negative transrespiratory pressure such that lung volume decreased below functional residual capacity. Allowing the lung to spontaneously recover revealed that the lung required ∼1 h of mechanical ventilation to return to the original state. We propose a number of possible mechanisms for these observations and suggest that they are most likely explained by the unfolding of alveolar septa and the subsequent redistribution of the fluid lining the alveoli at high transrespiratory pressure.

Background Manual ventilation is a key aspect that determines the efficiency of neonatal resuscitation and may be performed by specialists using different equipment and professionals. Objective To compare manual ventilation using T-piece resuscitator and self-inflating bag in an experimental model, with regard to gasometric and respiratory mechanical parameters. Methods Adult rabbits were submitted to 10 minutes of ventilation with each device operated by three groups of volunteers: physicians, physiotherapists, and nurses. We measured respiratory mechanics throughout the study as well as blood gas before and after ventilation, and we compared professionals' performance on each device. Results Compared with T-piece, animals ventilated with the self-inflating bag in the nurse group (n = 7) presented a greater minute volume (390 ± 108 vs. 766 ± 410 mL/min, p < 0.05) relative to the physiotherapist group (n = 7, 418 ± 192 vs. 886 ± 787 mL/min), and physician group (n = 7, 438 ± 206 vs. 705 ± 434 mL/min); similar results were found in the nurse, physiotherapist, and physician groups for respiratory alkalosis (7.40 ± 0.11 vs. 7.61 ± 0.02, p < 0.05; 7.37 ± 0.10 vs. 7.52 ± 0.23; and 7.36 ± 0.07 vs. 7.40 ± 0.18 mL/min, respectively), and hypocapnia (32.4 ± 6.9 vs. 23.4 ± 7.5 mm Hg, p < 0.05; 40.4 ± 10.8 vs. 28.0 ± 15.2 mm Hg; and 38.0 ± 13.8 vs. 42.6 ± 18.1 mm Hg, respectively). Conclusion Self-inflating bag resulted in hypocapnia and respiratory alkalosis in the nurse group, and ventilation using a T-piece resulted in a lower tidal and minute volume.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico
Durante o século XX, avanços teóricos e experimentais jogaramuma nova luz sobre o estudo da história e evolução do universo, a Cosmologia. A partir dos trabalhos de Edwin Hubble, a cosmologia moderna pôde ser vista como ciência. Mas foi nas últimas décadas, sobretudo, com o desenvolvimento da cosmologia de precisão e devido a uma melhor compreensão da natureza em seu nível mais fundamental, que a Cosmologia despertou maior interesse científico. Uma das fronteiras da área diz respeito ao universo muito jovem: modelos cosmológicos são baseados em uma teoria de gravitação; no entanto, o paradigma atual de teoria de gravitação, a Relatividade Geral de Einstein, quebra para regimes de energia acima da escala de Planck. Assim, para descrever o universo primitivo, quando a densidade de energia era muito alta, precisamos de uma nova teoria de gravitação. Uma teoria de gravitação capaz de lidar comos efeitos quânticos. Hoje nós temos uma candidata à tal teoria quântica de gravitação: Teoria de Cordas. Nesta dissertação, analisaremos um cenário cosmológico construído sobre Teoria de Cordas, o cenário cosmológico do gás de cordas, proposto originalmente por Robert Brandenberger e Cumrum Vafa. O cenário faz uso de simetrias e dualidades próprias de Teoria de Cordas e do fato de que um gás de cordas possui uma temperatura limitante para descrever o universo primordial e propôr respostas à questões abertas de cosmologia, como a formação da estrutura causal e a dimensionalidade do espaço-tempo. Uma das questões em aberto no cenário é a ocorrência ou não de inflação, uma era de crescimento exponencial do universo, que produz a estrutura causal observada experimentalmente e dilui relíquias produzidas no universo primordial para os níveis observados. Propondo uma interação entre as cordas do gás proporcional a seu acoplamento, estudamos a evolução resultante do universo e sob quais condições podemos ter umperíodo inflacionário

This diploma thesis is about thermomechanics of passenger car tires. The research part dealing with existing tire models is followed by the practical part. The practical part is based on the designs of thermomechanical models. The first model determines a dependence of temperature on the air pressure inside a tire when a temperature changes. The second thermomechanical model captures all the heat fluxes which affect a tire while a vehicle is in motion. The third thermomechanical model calculates temperatures of parts of the tire during driving tests. All models are programmed in MATLAB.

Inflationsmålets historia sträcker sig drygt 30 år tillbaka i tiden. En förutsägbar centralbank skapar möjligheter för marknadsaktörerna att sätta upp inflationsförväntningar i linje med det uppsatta målet som bidrar till att prisstegringstakten följer den önskade nivån. I dag har en stor majoritet av de mest ekonomiskt utvecklade länderna valt att införa ett inflationsmål som ett riktmärke för landets centralbank att rikta penningpolitiken mot. Samtidigt som inflationsnivåerna har sjunkit har också stora delar av länderna idag låga räntenivåer. Det innebär att centralbankens ammunition kan vara förbrukad ifall inflationen skulle behövas tryckas upp om inflationsnivån är under sitt mål. Syftet är att försöka förklara om inflationsmålet har haft någon betydelse avseende att minska inflationsvariansen samt om det även har haft en påverkan på BNP-gapet. För att undersöka inflationsmålets betydelse har vi undersökt flera ekonomiskt välutvecklade länder från inflationsmålets introduktion fram tills nu. Relevansen och legitimiteten i studien grundas på ett flertal tidigare studier. Studien ger en historisk överblick över inflationsnivån och dess stabilitet för länderna sedan 80-talet. Resultaten visar en stadig nedgång samt stabilisering på inflationen för samtliga länder. Däremot finner vi inga stöd för att det enbart skulle vara inflationsmålets förtjänst. Vi kan inte heller observera någon skillnad för BNP-gapet med eller utan inflationsmål. Även om vi inte kan hitta bevis på skillnader av att ha ett inflationsmål eller inte, så tror vi att det har haft en betydelse för de stabiliseringar som inflationen fått tack vare att aktörer lättare kan anpassa sina förväntningar mot målet.
The inflation target's history stretches back over 30 years. A predictable central bank creates opportunities for the market participants to set inflation expectations in line with what is set to be made at the price increase that follows the desired level. Today, a large majority of the most economically well-developed countries have chosen to introduce an inflation target as a benchmark for the country's central bank to target its monetary policy. At the same time as inflation levels have fallen, large proportion of the countries today also have low interest rates. This means that the central bank's ammunition can’t be used in case a rise of inflation is needed if the level of inflation is below its target. The purpose of the thesis is to explain whether the inflation target has had any significance in reducing the inflation variance and whether it has had an impact on the output-gap. To investigate the significance of the inflation target, we have examined several economically well-developed countries from the introduction of the inflation target until now. The relevance and legitimacy of the study is based on a number of previous studies in the field of inflation targeting. The study provides a historical overview of inflation levels and stability for countries since the 1980s. The results show a steady decline and stabilization of inflation for all countries. We find no support for it being solely the merit of the inflation target. Nor can we observe any difference for the GDP gap with or without inflation targets. Although we cannot find evidence of differences in having an inflation target or not, we believe that it has had an impact on the stabilizations that inflation has gained due to the fact that actors can more easily adjust their expectations to the target.

All over the world, the level of poverty is increasing. In South Africa it is mainly concentrated in rural areas and differs significantly from whether considering race, sex, provinces or community areas. This dissertation studies the relationship between poverty and inflation in Sharpeville by determining the impact of rising prices on the poor households in Sharpeville. The study focuses on three areas, namely the theoretical background of poverty and inflation, the impact of rising prices in expenditure patterns and the relationship to poverty. There are different approaches in defining poverty. Poverty can either be absolute or relative. For the purpose of this study, poverty is defined as absolute. Thus the study defines individuals as poor due to their inability to attain a minimum material standard of living. This minimal standard of living is normally referred to as the poverty line. Inflation may be defined in different ways. For the purpose of this dissertation, inflation is defined as the rise in the general price levels over a specific period of time. Changes in expenditure patterns are caused by an increase in inflation. This study uses the regression model to determine the impact of inflation on poverty in Sharpeville. According to the macroeconomic theory’s implication, the same level of inflation on the same basket of commodities has a different level of effect on each household. Accordingly, in this study, all households are assumed to be faced with the same inflation rate. Household size is positively related to poverty gap squared. This means that the more members there were in a household in Sharpeville the poorer they were. Households with the highest number of members were poorer than those with few members. Statistically, the null hypothesis that there is no relationship between household size and poverty gap is rejected, even at the 1% level of significance. EXPINFL is negatively related to poverty gap. The correlation matrix confirms the results in the regression analysis. The correlation coefficient between The relationship between poverty and inflation in Sharpeville Page EXPINFL and PGAP is -0.34467. Although it is relatively weak, the fact that there is a negative correlation confirms that inflation negatively affects poverty. Finally, the study recommends that government provides more job opportunities for the individuals without any source of income in Sharpeville. The government could also provide business funding to the unemployed individuals to enable them to start their own businesses. This would enable those individuals to create additional employment. In addition, measures should be introduced to determine the effect of inflation on those households who are not employed (that is, not receiving any form of income, not even through any form of grant), but do benefit from some form of feeding scheme administered by either government or non-profit organisations.
MCom, Economics, North-West University, Vaal Triangle Campus, 2012

Output gap belongs to standard indicators of inflationary pressures used in central banks. The aim of this paper is to find the answer to the question, whether we can consider output gap as a suitable indicator of inflation for the Czech economy. First hypothesis, which we analysed is that we can estimate output gap only with uncertainty. For confirmation or refutation of this hypothesis we used ten models of estimation of output gap. The second hypothesis is that output gap can be used as suitable indicator of inflation. For testing of this hypothesis we chose gap model from Coe, McDetmott (1997) -- with the level of output gap and the change (difference) of output gap. All tests confirmed, that central bank can use inflation as a useful indicator of inflation.

The purpose of this paper is to examine how a current-looking Taylor rule explains the setting of the repo rate by the Riksbank between 1995-2018 vis-à-vis a forward-looking Taylor rule. Furthermore, we investigate whether the explanatory power of these rules change after the financial crisis. The implied Taylor rates are calculated using our own estimates of the natural rate of interest. These rates are then plotted on a graph creating a span of uncertainty in which the repo rate can be set between. Finally, we regress the repo rate on the Taylor rates. In this way, we examine which rule is more in line with the repo rate. The results showed that a forward-looking Taylor rule based on a varying real interest rate is more in line with the repo rate than the current-looking rule, both for the period as a whole and after 2008. The explanatory power of both rules decreases in the period following 2008.

Le modèle cosmologique standard possède plusieurs lacunes pour une description pertinente de l'évolution de notre univers et de ses constituants. Tout d'abord, il laisse en suspens l'explication de l'origine de la matière noire et de l'énergie sombre. Ces composants, introduits ad hoc afin de satisfaire aux observations, représentent ensemble environ 95% du contenu en énergie de l'univers. Un second problème concerne l'indépendance d'échelle du modèle : quel que soit l'échelle du système considéré, il est attendu une dynamique et une géométrie identiques. Il est possible de se détourner du modèle standard et de s'intéresser à des cosmologies inhomogènes et à leur évolution moyenne. Selon ce formalisme, les inhomogénéités au sein d'une échelle influencent globalement la dynamique de cette dernière par un effet dit de rétroaction. Cette démarche très riche propose également une explication élégante au problème des constituants sombres : tous deux apparaissent comme une manifestation effective des inhomogénéités de distributions de matière et de géométrie. Cette thèse s'intéresse aux propriétés des modèles inhomogènes moyennés en relativité générale. Nous proposons dans un premier temps de décrire le comportement global des inhomogénéités selon une évolution de Chaplygin, et selon une évolution de Ginzburg-Landau. Nous montrons également l'instabilité gravitationnelle globale des solutions de Friedmann-Lemaître-Robertson-Walker. Cette classe de solutions est connue comme étant localement instable sous l'introduction de perturbations ; ici nous montrons qualitativement qu'elle ne fournit pas, en général, une approximation correcte en tant que fond physique. Nous présentons finalement une nouvelle théorie relativiste perturbative, pour laquelle les inhomogénéités scalaires évoluent autour d'un fond général, et non plus autour d'un fond de Friedmann-Lemaître-Robertson-Walker pré-défini. Cette nouvelle étude étend l'applicabilité des cosmologies inhomogènes, et pourrait éventuellement expliquer la formation des grandes structures sans recours à l'énergie noire

Inflationen har i många länder varit låg sedan finanskrisen 2008. I försök öka inflationstakten har centralbanker sänkt sina räntor till rekordlåga nivåer. I Danmark, Schweiz och Sverige har styrräntorna varit negativa. John B Taylor föreslog 1993 en makroekonomisk regel med syfte att kunna ge en prognos för styrräntan. Enligt Taylorregeln kan styrräntan förklaras av tidigare perioders inflationstakt och bruttonationalprodukt. Denna uppsats syftar till att undersöka Taylorregelns empiriska relevans i Danmark, Schweiz och Sverige under perioden 2000 till 2018. Två tester genomförs. Det första är att, med en linjär regressionsmodell, undersöka sambandet mellan styrränta, inflationsgap och BNP-gap. Det andra är ett Granger-kausalitetstest för att se om den implicerade kausaliteten i Taylorregeln stämmer. Granger-testet bygger på resultaten från en vektor autoregression. Resultaten i denna uppsats visar att det finns ett samband mellan inflationstakt och styrränta, men inte mellan BNP-gap och styrränta i de valda länderna under undersökningsperioden. Vidare visar resultaten att kausaliteten går från inflationsgap och BNP-gap mot styrränta, som Taylorregeln föreslår. Resultatet lyckas inte påvisa att negativa styrräntor skulle påverka Taylorregelns relevans.
The rate of inflation has been low in many countries since the financial crisis in 2008. In attempts to increase the inflation rate, central banks have lowered their interest rates to historically low levels. In Denmark, Switzerland and Sweden, the central banks key interest rates have been negative. In 1993, John B Taylor proposed a macroeconomic rule with the aim of providing a forecast for the key interest rate. According to the Taylor rule, the policy rate can be explained by the inflation rate and gross domestic product of previous periods. This paper aims to investigate the empirical relevance of the Taylor rule in Denmark, Switzerland and Sweden during the period 2000 to 2018. To do this, two tests are performed. The first is that, with a linear regression model, investigate the relationship between the key interest rate, the inflation gap and the GDP gap. The second is a Granger causality test to see if the implicit causality of the Taylor rule is correct. The Granger test is based on the results of a vector autoregression. The results of this paper show that there is a correlation between the rate of inflation and the key interest rate, but not between the GDP gap and the key interest rate in the selected countries during the investigation period. Furthermore, the results show that causality goes from the inflation gap and the GDP gap towards the key interest rate, as the Taylor rule suggests. The result does not suggest that negative key interest rates would affect the relevance of the Taylor rule.

By monetary policy decisions, central banks use output gap to keep macroeconomic variables at their natural levels. A substantial disadvantage of this variable is the fact that it is an unobservable variable which is very problematic to measure, although it is possible to estimate it with various methods of estimation. This thesis aims to find the most suitable method of estimation for Czech economy. Thirteen methods have been chosen for this aim: linear trend, quadratic trend, HP filter, band-pass filters, robust trend, univariate unobserved component model, two types of production function, two SVAR models, multivariate HP filter and multivariate unobserved component model. Own estimations have shown that estimated trajectories of unobservable states were not identical. For own selection of the most suitable method of estimation, quantitative (ability to forecast inflation ,a growth of product and data revisions by selected national and international organisations) and qualitative criterions (qualities of methods of estimation, transparency and easy application) have been selected, where emphasis was put on quantitative criterions. Results of this thesis will show that the most suitable method of estimation output gap for Czech economy is multivariate unobserved component model.

This paper presents dynamic results for spherical dielectric elastomer actuators subject to an inflating mechanical pressure and an applied voltage. Different equilibria modes arise during dynamic operation due to inertial effects. In previous work, the inertial effects have been studied for the limited case of a constant applied pressure during membrane deformation [1]. Here, novel results are presented in which the dynamic response of spherical dielectric elastomer actuators to a pressure-time loading history as well as a more realistic constant gas flow rate are considered. The results are calculated for both the damped and the zero-damped cases. The spherical membrane is assumed to follow the Mooney material model where various inflation modes arise depending on the material parameters. The range of Mooney material parameters considered, the driving pressure and the applied voltage all affect the dynamic response.

This paper updates on the recent development of the novel Solid State Inflation Balloon (SSIB), a simple, reliable, low-cost, non-propulsive deorbit mechanism for the full range of small satellites, defined by NASA as less than 180 kg. It aims to focus on the recent demonstration, for the first time, inflation of a ∼10 cm sized balloon in a vacuum chamber. Small satellites typically rely on aerodynamic drag to deorbit within the FAA’s 25 year requirements. The SSIB will enhance aerodynamic drag by inflating a balloon at the end-of-life of a satellite mission. This technology will provide a scalable and non-existing capability, low-cost deorbit, for applications in the full-range of smallsats, from CubeSats to MicroSats. The SSIB system is composed of three major components: a Micro-Electro-Mechanical Systems (MEMS) Solid-State Gas Generator (SSGG) chip, a balloon structure made of thin film compatible with space environment (i.e. Mylar, Kapton, or Teflon), and a sub-system package suitable for spacecraft integration. The SSGG is composed of a 2D addressable array of sodium azide (NaN3) crystals, confined by Su-8 wells, on a glass substrate. Current versions include 2×2 and 8×8 arrays designed for a full range of small satellites. Under each well is a resistive heater and when heated to above 350 °C, the NaN3 spontaneously decomposes to generate N2 gas in time scales on the order of 10 milliseconds. Each well is designed with a typical volume of 10–15 m3 to 10−6 m3 of NaN3 (i.e. 1,500 μm × 1,500 μm × 150 μm on the larger end of the spectrum). The SSIB system is low power (∼1 W per well for less than 10 seconds) and have low mass (∼100 grams, where mass is dominated by the size of the required balloon). Initial simulations have shown that the SSIB with balloons of 1 m2 cross-section can deorbit small satellites from above 1000 km well within 25 years.

The deployment of an airbag is most fatal and dangerous to a passenger when they are in an out of position (OOP) situation, with the airbag making contact before it is fully inflated. This can lead to severe, if not life threatening, injuries to the passenger. This situation is more commonly associated with small females and children who are positioned near to the airbag module, i.e. in an OOP load cases. The aim of this research is to assess the response of a Hybrid III 5th Percentile female anthropomorphic dummy positioned in a FMVSS 208 low risk static airbag deployment OOP load cases using a transient dynamic finite element program called LS-DYNA. The simulation considers the standard procedures utilised in the LS-DYNA, where assumptions such as uniform airbag pressure and temperature are made, along with a more recently developed procedure that takes into account the fluid-structure interaction between the inflating gas source and the airbag fabric, referred to as Arbitrary Lagrangain Eulerian (ALE) theory. Both simulations were compared to test data received by Jaguar, indicating satisfactory results in terms of correlation, with the more recently developed procedure, ALE theory, showing the greatest accuracy, both in terms of graphical and schematic comparison, especially in the very early stages of the inflation process. As a result, the new simulation procedure model was utilised to research into the effects of changing the designs of the airbag module.

In this paper we report on the current development of the Solid State Inflation Balloon (SSIB), a simple, reliable, low-cost, non-propulsive deorbit mechanism for the full range of small satellites (<180kg). Small satellites typically rely on aerodynamic drag to deorbit within the FAA’s 25 year requirements. The SSIB will enhance aerodynamic drag by inflating a balloon at the end-of-life of a satellite mission. This technology will provide a scalable and non-existing capability, low-cost deorbit, for applications in the full-range of smallsats, from CubeSats to MicroSats. The proposed SSIB system is composed of three major components: a Micro-Electro-Mechanical Systems (MEMS) Solid-State Gas Generator (SSGG) chip, a balloon structure made of thin metallized polyimide films such as Kapton® HN composed of multiple lenticular gores which will form a spherical balloon, and a subsystem package suitable for spacecraft integration. The SSGG is composed of a 2D addressable array of Sodium Azide (NaN3) crystals on a glass substrate. The crystals are contained in wells formed by a thick-film of epoxy polymer (SU-8). Under each well is a resistive heater that is selectively addressed using Metal-Insulator-Metal (MIM) diode networks. When heated to above 350 °C, the NaN3 spontaneously decomposes to generate N2 gas in time scales on the order of 10 milliseconds. Each well can be designed with a typical volume of 10−15 m3 to 10−6 m3 of NaN3. The SSIB system has built-in redundancy due to the fact that the SSGG is a scalable chip design and can incorporate as many gas generating wells as a mission may dictate. Additionally, the SSIB can mitigate balloon leaks by sequential deployment of additional gas wells and can thereby maintain the inflated state of the balloon. The SSIB system will be low power (< 1 W) and have low mass (mass is proportional to the size of the required balloon). Initial simulations have shown that the SSIB can deorbit small satellites from above 1000 km within 25 years.

Inspired by the characteristics of biological muscles, rubber muscle actuators (RMAs) are lightweight and compliant structures that deliver high power/weight ratios and are currently under investigation for use in soft robotics, prosthetics, and specialized aircraft. RMA actuation is accomplished by inflating the structure’s air bladder, which results in the contraction of the muscle. In this proceedings paper, we describe the use of gaseous products from enzymatically-catalyzed reactions to pressurize and drive the motion of RMAs. Specifically, this paper details the power envelope of RMAs driven by the urease-catalyzed production of CO2, under dynamic loading conditions. The use of enzymatically catalyzed, gas-producing reactions is advantageous for powering RMAs, as these systems may be self-regulating and self-regenerating. Reaction design parameters for sizing the gas source to RMA power requirements and power envelope results are reported for gas-powered actuator dynamics tested on a linear motion test assembly. The power response to increasing loads reflects the partial pressure over the reaction slurry; therefore, the chemistry and reactor scale affect the entire structure’s efficiency. We outline the reactor space-time design constraints that facilitate a tailored power response for urease catalyzed gas generation sources.

A method is outlined for determining the optimum operating conditions of a turbine-generator unit installed across a low-head irrigation structure for electrical power generation. For a given regulator’s characteristic, the unit’s rated power and design parameters are determined such that its cost-benefit ratio is minimum. The economical feasibility of the microhydro plant is studied by comparing its life-time cost to its life-time benefit. The benefit is determined by the cost of the corresponding energy generated through a diesel-driven generator set. The microhydro plant was found to be economically feasible over a wide range of inflation and interest rates.

1.1 Macroeconomic summary Economic recovery has consistently outperformed the technical staff’s expectations following a steep decline in activity in the second quarter of 2020. At the same time, total and core inflation rates have fallen and remain at low levels, suggesting that a significant element of the reactivation of Colombia’s economy has been related to recovery in potential GDP. This would support the technical staff’s diagnosis of weak aggregate demand and ample excess capacity. The most recently available data on 2020 growth suggests a contraction in economic activity of 6.8%, lower than estimates from January’s Monetary Policy Report (-7.2%). High-frequency indicators suggest that economic performance was significantly more dynamic than expected in January, despite mobility restrictions and quarantine measures. This has also come amid declines in total and core inflation, the latter of which was below January projections if controlling for certain relative price changes. This suggests that the unexpected strength of recent growth contains elements of demand, and that excess capacity, while significant, could be lower than previously estimated. Nevertheless, uncertainty over the measurement of excess capacity continues to be unusually high and marked both by variations in the way different economic sectors and spending components have been affected by the pandemic, and by uneven price behavior. The size of excess capacity, and in particular the evolution of the pandemic in forthcoming quarters, constitute substantial risks to the macroeconomic forecast presented in this report. Despite the unexpected strength of the recovery, the technical staff continues to project ample excess capacity that is expected to remain on the forecast horizon, alongside core inflation that will likely remain below the target. Domestic demand remains below 2019 levels amid unusually significant uncertainty over the size of excess capacity in the economy. High national unemployment (14.6% for February 2021) reflects a loose labor market, while observed total and core inflation continue to be below 2%. Inflationary pressures from the exchange rate are expected to continue to be low, with relatively little pass-through on inflation. This would be compatible with a negative output gap. Excess productive capacity and the expectation of core inflation below the 3% target on the forecast horizon provide a basis for an expansive monetary policy posture. The technical staff’s assessment of certain shocks and their expected effects on the economy, as well as the presence of several sources of uncertainty and related assumptions about their potential macroeconomic impacts, remain a feature of this report. The coronavirus pandemic, in particular, continues to affect the public health environment, and the reopening of Colombia’s economy remains incomplete. The technical staff’s assessment is that the COVID-19 shock has affected both aggregate demand and supply, but that the impact on demand has been deeper and more persistent. Given this persistence, the central forecast accounts for a gradual tightening of the output gap in the absence of new waves of contagion, and as vaccination campaigns progress. The central forecast continues to include an expected increase of total and core inflation rates in the second quarter of 2021, alongside the lapse of the temporary price relief measures put in place in 2020. Additional COVID-19 outbreaks (of uncertain duration and intensity) represent a significant risk factor that could affect these projections. Additionally, the forecast continues to include an upward trend in sovereign risk premiums, reflected by higher levels of public debt that in the wake of the pandemic are likely to persist on the forecast horizon, even in the context of a fiscal adjustment. At the same time, the projection accounts for the shortterm effects on private domestic demand from a fiscal adjustment along the lines of the one currently being proposed by the national government. This would be compatible with a gradual recovery of private domestic demand in 2022. The size and characteristics of the fiscal adjustment that is ultimately implemented, as well as the corresponding market response, represent another source of forecast uncertainty. Newly available information offers evidence of the potential for significant changes to the macroeconomic scenario, though without altering the general diagnosis described above. The most recent data on inflation, growth, fiscal policy, and international financial conditions suggests a more dynamic economy than previously expected. However, a third wave of the pandemic has delayed the re-opening of Colombia’s economy and brought with it a deceleration in economic activity. Detailed descriptions of these considerations and subsequent changes to the macroeconomic forecast are presented below. The expected annual decline in GDP (-0.3%) in the first quarter of 2021 appears to have been less pronounced than projected in January (-4.8%). Partial closures in January to address a second wave of COVID-19 appear to have had a less significant negative impact on the economy than previously estimated. This is reflected in figures related to mobility, energy demand, industry and retail sales, foreign trade, commercial transactions from selected banks, and the national statistics agency’s (DANE) economic tracking indicator (ISE). Output is now expected to have declined annually in the first quarter by 0.3%. Private consumption likely continued to recover, registering levels somewhat above those from the previous year, while public consumption likely increased significantly. While a recovery in investment in both housing and in other buildings and structures is expected, overall investment levels in this case likely continued to be low, and gross fixed capital formation is expected to continue to show significant annual declines. Imports likely recovered to again outpace exports, though both are expected to register significant annual declines. Economic activity that outpaced projections, an increase in oil prices and other export products, and an expected increase in public spending this year account for the upward revision to the 2021 growth forecast (from 4.6% with a range between 2% and 6% in January, to 6.0% with a range between 3% and 7% in April). As a result, the output gap is expected to be smaller and to tighten more rapidly than projected in the previous report, though it is still expected to remain in negative territory on the forecast horizon. Wide forecast intervals reflect the fact that the future evolution of the COVID-19 pandemic remains a significant source of uncertainty on these projections. The delay in the recovery of economic activity as a result of the resurgence of COVID-19 in the first quarter appears to have been less significant than projected in the January report. The central forecast scenario expects this improved performance to continue in 2021 alongside increased consumer and business confidence. Low real interest rates and an active credit supply would also support this dynamic, and the overall conditions would be expected to spur a recovery in consumption and investment. Increased growth in public spending and public works based on the national government’s spending plan (Plan Financiero del Gobierno) are other factors to consider. Additionally, an expected recovery in global demand and higher projected prices for oil and coffee would further contribute to improved external revenues and would favor investment, in particular in the oil sector. Given the above, the technical staff’s 2021 growth forecast has been revised upward from 4.6% in January (range from 2% to 6%) to 6.0% in April (range from 3% to 7%). These projections account for the potential for the third wave of COVID-19 to have a larger and more persistent effect on the economy than the previous wave, while also supposing that there will not be any additional significant waves of the pandemic and that mobility restrictions will be relaxed as a result. Economic growth in 2022 is expected to be 3%, with a range between 1% and 5%. This figure would be lower than projected in the January report (3.6% with a range between 2% and 6%), due to a higher base of comparison given the upward revision to expected GDP in 2021. This forecast also takes into account the likely effects on private demand of a fiscal adjustment of the size currently being proposed by the national government, and which would come into effect in 2022. Excess in productive capacity is now expected to be lower than estimated in January but continues to be significant and affected by high levels of uncertainty, as reflected in the wide forecast intervals. The possibility of new waves of the virus (of uncertain intensity and duration) represents a significant downward risk to projected GDP growth, and is signaled by the lower limits of the ranges provided in this report. Inflation (1.51%) and inflation excluding food and regulated items (0.94%) declined in March compared to December, continuing below the 3% target. The decline in inflation in this period was below projections, explained in large part by unanticipated increases in the costs of certain foods (3.92%) and regulated items (1.52%). An increase in international food and shipping prices, increased foreign demand for beef, and specific upward pressures on perishable food supplies appear to explain a lower-than-expected deceleration in the consumer price index (CPI) for foods. An unexpected increase in regulated items prices came amid unanticipated increases in international fuel prices, on some utilities rates, and for regulated education prices. The decline in annual inflation excluding food and regulated items between December and March was in line with projections from January, though this included downward pressure from a significant reduction in telecommunications rates due to the imminent entry of a new operator. When controlling for the effects of this relative price change, inflation excluding food and regulated items exceeds levels forecast in the previous report. Within this indicator of core inflation, the CPI for goods (1.05%) accelerated due to a reversion of the effects of the VAT-free day in November, which was largely accounted for in February, and possibly by the transmission of a recent depreciation of the peso on domestic prices for certain items (electric and household appliances). For their part, services prices decelerated and showed the lowest rate of annual growth (0.89%) among the large consumer baskets in the CPI. Within the services basket, the annual change in rental prices continued to decline, while those services that continue to experience the most significant restrictions on returning to normal operations (tourism, cinemas, nightlife, etc.) continued to register significant price declines. As previously mentioned, telephone rates also fell significantly due to increased competition in the market. Total inflation is expected to continue to be affected by ample excesses in productive capacity for the remainder of 2021 and 2022, though less so than projected in January. As a result, convergence to the inflation target is now expected to be somewhat faster than estimated in the previous report, assuming the absence of significant additional outbreaks of COVID-19. The technical staff’s year-end inflation projections for 2021 and 2022 have increased, suggesting figures around 3% due largely to variation in food and regulated items prices. The projection for inflation excluding food and regulated items also increased, but remains below 3%. Price relief measures on indirect taxes implemented in 2020 are expected to lapse in the second quarter of 2021, generating a one-off effect on prices and temporarily affecting inflation excluding food and regulated items. However, indexation to low levels of past inflation, weak demand, and ample excess productive capacity are expected to keep core inflation below the target, near 2.3% at the end of 2021 (previously 2.1%). The reversion in 2021 of the effects of some price relief measures on utility rates from 2020 should lead to an increase in the CPI for regulated items in the second half of this year. Annual price changes are now expected to be higher than estimated in the January report due to an increased expected path for fuel prices and unanticipated increases in regulated education prices. The projection for the CPI for foods has increased compared to the previous report, taking into account certain factors that were not anticipated in January (a less favorable agricultural cycle, increased pressure from international prices, and transport costs). Given the above, year-end annual inflation for 2021 and 2022 is now expected to be 3% and 2.8%, respectively, which would be above projections from January (2.3% and 2,7%). For its part, expected inflation based on analyst surveys suggests year-end inflation in 2021 and 2022 of 2.8% and 3.1%, respectively. There remains significant uncertainty surrounding the inflation forecasts included in this report due to several factors: 1) the evolution of the pandemic; 2) the difficulty in evaluating the size and persistence of excess productive capacity; 3) the timing and manner in which price relief measures will lapse; and 4) the future behavior of food prices. Projected 2021 growth in foreign demand (4.4% to 5.2%) and the supposed average oil price (USD 53 to USD 61 per Brent benchmark barrel) were both revised upward. An increase in long-term international interest rates has been reflected in a depreciation of the peso and could result in relatively tighter external financial conditions for emerging market economies, including Colombia. Average growth among Colombia’s trade partners was greater than expected in the fourth quarter of 2020. This, together with a sizable fiscal stimulus approved in the United States and the onset of a massive global vaccination campaign, largely explains the projected increase in foreign demand growth in 2021. The resilience of the goods market in the face of global crisis and an expected normalization in international trade are additional factors. These considerations and the expected continuation of a gradual reduction of mobility restrictions abroad suggest that Colombia’s trade partners could grow on average by 5.2% in 2021 and around 3.4% in 2022. The improved prospects for global economic growth have led to an increase in current and expected oil prices. Production interruptions due to a heavy winter, reduced inventories, and increased supply restrictions instituted by producing countries have also contributed to the increase. Meanwhile, market forecasts and recent Federal Reserve pronouncements suggest that the benchmark interest rate in the U.S. will remain stable for the next two years. Nevertheless, a significant increase in public spending in the country has fostered expectations for greater growth and inflation, as well as increased uncertainty over the moment in which a normalization of monetary policy might begin. This has been reflected in an increase in long-term interest rates. In this context, emerging market economies in the region, including Colombia, have registered increases in sovereign risk premiums and long-term domestic interest rates, and a depreciation of local currencies against the dollar. Recent outbreaks of COVID-19 in several of these economies; limits on vaccine supply and the slow pace of immunization campaigns in some countries; a significant increase in public debt; and tensions between the United States and China, among other factors, all add to a high level of uncertainty surrounding interest rate spreads, external financing conditions, and the future performance of risk premiums. The impact that this environment could have on the exchange rate and on domestic financing conditions represent risks to the macroeconomic and monetary policy forecasts. Domestic financial conditions continue to favor recovery in economic activity. The transmission of reductions to the policy interest rate on credit rates has been significant. The banking portfolio continues to recover amid circumstances that have affected both the supply and demand for loans, and in which some credit risks have materialized. Preferential and ordinary commercial interest rates have fallen to a similar degree as the benchmark interest rate. As is generally the case, this transmission has come at a slower pace for consumer credit rates, and has been further delayed in the case of mortgage rates. Commercial credit levels stabilized above pre-pandemic levels in March, following an increase resulting from significant liquidity requirements for businesses in the second quarter of 2020. The consumer credit portfolio continued to recover and has now surpassed February 2020 levels, though overall growth in the portfolio remains low. At the same time, portfolio projections and default indicators have increased, and credit establishment earnings have come down. Despite this, credit disbursements continue to recover and solvency indicators remain well above regulatory minimums. 1.2 Monetary policy decision In its meetings in March and April the BDBR left the benchmark interest rate unchanged at 1.75%.