Excess Sources Research Articles

Stabilizing the nanostructure of Pre-lithiated LiF nanoparticles modified SnO2@graphite nanosheets as a high performance anode material for lithium ions batteries

Graphite nanosheets coated by LiF/SnO2 composites are designed to obtain a lithium ion anode material with excellent performance. LiF nanoparticles play a significant role in improving the electrochemical performance by inhibiting electrolyte decomposition and providing excess Li sources during cycling. The obtained LiF@SnO2@C electrode shows an outstanding capacity of 951.9 mAhg−1 at 0.2 Ag-1 after 370 cycles and excellent long cycling performance of 650.0 mAhg−1 at 1.0 Ag-1 after 930 cycles. First-principles calculations demonstrate that F-doped SnO2 (−2211.8 eV) has a lower free energy compared to SnO2 (−1937.4 eV), resulting in a robust composite architecture that gives rise to high cycling stability.

Potential Diffusion of Renewables-Based DH Assessment through Clustering and Mapping: A Case Study in Milano

This work aims at developing a methodology for the assessment of district heating (DH) potential through the mapping of energy demand and waste heat sources. The presented method is then applied to the Metropolitan City of Milano as a case study in order to investigate the current and, especially, the future sustainability of DH with the foreseen building refurbishment and consequent heat demand reduction. The first step is the identification of the areas the most interesting from a heat density and an economic point of view through a clustering algorithm, in which lies the main novelty of the work. The potential is then assessed by investigating their synergy with the available heat sources, which are mapped and analyzed in terms of recoverable thermal energy and costs. In future scenarios with foreseen heat demand reduction, low-temperature networks and excess heat sources are considered, such as metro stations and datacenters, together with the conventional sources, such as thermoelectric plants. The outcomes prove that lower heat demand corresponds to higher network costs with consequently reduced district heating potential but also prove that the properties of low-temperature district heating can potentially compensate for the drop in its cost-effectiveness. Another interesting finding is that the renovation of buildings in an area should be not performed evenly but with criteria; for instance, in synergy with DH diffusion.

Limited Efficacy of Mifepristone Due to Poor Tolerance: A Clinical Challenge in Managing Cortisol Excess

A 53-year male with incidental bilateral adrenal masses along with symptoms of proximal muscle weakness, anxiety, and depression. Past medical history of uric acid nephrolithiasis, hypertension, hyperlipidemia, type 2 diabetes mellitus, anxiety, and depression. A right adrenal mass of 2.8cm and a left adrenal mass of 1.5cm both of <10 HU on non-enhancing CT. Hormonal activity workup was ordered which showed cortisol levels of 4.7mcg/dL on 1mg ONDST suggestive of autonomous cortisol excess and workup for primary hyperaldosteronism was negative. On follow up CT adrenal masses remained stable, but the patient underwent the annual hormonal workup for incidentaloma with 1mg ONDST and found with cortisol 4.5mcg/dL, eventually repeated with 2-day LDDST which showed no suppression of cortisol with levels at 4.5 mcg/dL confirming the diagnosis of autonomous cortisol excess. ACTH found to be suppressed at 3.1pg/dL (7.2–63.3 pg/dL) which helped confirm the diagnosis of non-ACTH dependent autonomous cortisol excess. Referred to surgery evaluation due to complications associated with cortisol excess as osteoporosis and uncontrolled hyperglycemia however surgical intervention was deferred until the source of cortisol excess could be identified within the bilateral adrenal masses and it was recommended to continue with medical therapy.As the cortisol excess source cannot be identified by localizing procedures and despite adequate medical therapy and stable adrenal masses on imaging, patient persisted with uncontrolled DM/hypertension and worsening BMD in the spine and hip with surgery not being an option. The patient was started on glucocorticoid receptor antagonist mifepristone in which upon reevaluation weakness and fatigue were noticeable along with hypokalemia of 3.1mmol/L after 2 weeks of therapy that was eventually replaced but 2 weeks later the patient discontinued therapy as he could not tolerate side effects related to adrenal insufficiency associated with mifepristone, such as weakness, fatigue, and dependence of potassium supplementation due to hypokalemia.This effect is physiologically important, because cortisol binds as avidly as aldosterone to the mineralocorticoid receptor, and the plasma cortisol concentration is approximately 100-fold higher than the plasma aldosterone concentration and it can lead to hypokalemia by the mechanism of apparent mineralocorticoid excess. Also, as mifepristone blocks cortisol action, the levels of ACTH and cortisol increase so high that hormonal measurement cannot be used to judge either therapeutic efficacy or adrenal insufficiency, we must go based on signs and symptoms.

Tunable multiwavelength optical comb enabledRoF‐OFDM‐PONwith wavelength multiplex

AbstractWe propose a hybrid full duplex passive optical network with fusion of wavelength‐division‐multiplexing and orthogonal frequency‐division multiplexing (WDM‐OFDM) for a radio‐over‐fiber (RoF) system application. The key of the system is a tunable optical frequency comb (OFC) embedded cascading modulators and a parameter mixer. Moreover, 23 frequency components with 0.6 dB flatness generated by the OFC are used as light sources for each WDM channel. We utilize a 7.5 GHz OFDM wired signal and a 12.5 GHz OFDM wireless signal for downstream transmission and 10 Gb/s OOK (on–off keyed) signals for upstream traffic. Using polarization multiplexing technique, we extract a central optical carrier to bear the upstream signal so that no excess optical source is introduced into the ONU. Thus, the intricacy and costs of system are diminished. Moreover, successful transmission has been demonstrated since the bit error rates of the downstream and upstream signals are always under the adopted forward error correction limit. Furthermore, the proposed system can enhance power budget and reduce cost, which has a promising prospect for future wireless communication.

Lipid composition of the microbial mat from a hypersaline environment (Vermelha Lagoon, Rio de Janeiro, Brazil)

ABSTRACTThis study determines organic-matter (OM) composition in the different color layers of a stratified hypersaline microbial mat and verifies the hypothesis that each layer includes a distinct group of lipids. The relation of precursor lipids from the microbial mat to the hydrocarbon composition in fossil records was also evaluated. To that end, the composition was studied of glycolipids (GLs), phospholipids (PLs), and “neutral” lipids (NLs, including hydrocarbons, n-alkanols, sterols, hopanols, free fatty acids, and wax esters) in four different color layers (A–D; depth intervals: up to 0.5 cm, 0.5–1.0 cm, 1.5–3.0 cm, and 3.0–6.0 cm, respectively) of a stratified hypersaline mat from the Vermelha Lagoon, Rio de Janeiro, Brazil.Microscopic characterization revealed the presence of 16 cyanobacterial morphospecies, with predominance of Microcoleus chthonoplastes. The notable prevalence of saturated straight-chain fatty acids (FAs), n-16:0 and n-18:0 and their monounsaturated counterparts, n-16:1 and n-18:1 in all three lipid fractions (GLs, PLs, and NLs), associated with the domination of n-C17 alkane and n-C17:1 alkene among the hydrocarbons confirmed the main imprint of cyanobacteria. The composition of the studied lipid classes implies the contribution of sulfate-reducing bacteria such as Desulfomicrobium sp. strain, purple sulfur bacteria, as well as the possible input of Geobacter spp. and Desulfovibrio spp., particularly in the deeper layers.The notable decrease in total extractable lipids (TELs) yield from layers A to D indicates that lipid synthesis is far more intense by photosynthesizing cyanobacteria than by anaerobic microorganisms. The content of PLs was uniform and low (&amp;lt; 5%) in all layers, implying their extremely quick degradation. GLs, followed by NLs, were the most abundant in all layers indicating the medium, which is characterized by carbon source excess and limited nitrogen source, which regulates microorganism growth. The upper layers, A (green) and B (reddish-brown) differ from those lower, C (dark brown greenish) and D (brown) according to the NLs/GLs ratio, which is higher in the former.The lipid compositions reveal distinctions between the individual layers in the microbial mat. The observed layers clearly differ according to the amount of high-molecular-weight (C22–C31) n-alkanes and long-chain (C21–C30) n-alkanols, the content of phytol, bishomohopanol, tetrahymanol, C27–C29 sterols, the stanol/stenol ratio in the neutral lipid fraction, as well as the content of branched (iso and anteiso) FAs and w9/w7 FA ratio in the GLs fraction. The mentioned parameters imply a greater contribution of sulfate-reducing and purple sulfur bacteria to layer B, higher impact of photosynthetic red algae in upper layers A and B, the elevated contribution of marine ciliate species, feeding on bacteria to layers B and C, as well as the increment of anoxygenic phototrophic and heterotrophic bacteria to layer D. The greatest capability for the synthesis of hydrocarbons is observed in layer B.The composition of lipid classes in the microbial mat showed a significant relationship with the most important biomarkers' fingerprints in the source rocks extracts and petroleum derived from the carbonate hypersaline environments, including the distribution of n-alkanes, a high abundance of phytane and gammacerane, as well as a distribution of C27–C29 regular steranes. Therefore, these results offer an insight into the transformation of microbial OM during the sedimentation processes in a hypersaline environment and its contribution to the fossil record.

Utilizing excess heat through a wholesale day ahead heat market – The DARKO model

District heating has already proven to be a suitable solution for the decarbonisation of the most energy intensive energy sector in Europe, heating and cooling. However, to achieve this, it needs to incorporate renewable and sustainable energy sources into the generation mix which is still dominated by fossil fuels in many countries. Alongside traditional renewables like solar thermal, geothermal and biomass, excess heat from the industrial and service sector has a high untapped potential. Nonetheless, to utilize it in district heating, third party access must be granted. For that reason, a wholesale day ahead heat market has been modelled in this study and validated on a case study in the city of Sisak in Croatia. The idea was twofold: to evaluate the functionality of such a heat market and its effect on the existing system, as well as to analyse the integration of high and low temperature excess heat sources in different conditions, including the use of thermal storage, as well as the competition with low-cost renewables, i.e. solar thermal. The results have shown that the introduction of a wholesale day ahead heat market would ensure the positive total welfare in all the scenarios. The benefit for the demand side and the total welfare would increase even more if excess heat sources are integrated in the system and especially if they are combined with a thermal storage to increase their capacity factor, which would also decrease the competing effect of solar thermal. Finally, it was shown that low temperature excess heat is not feasible in the high temperature district heating and the transfer to the 4th generation district heating is required to feasibly utilise low temperature sources.

Highly Flexible, Stretchable, and Self-Powered Strain-Temperature Dual Sensor Based on Free-Standing PEDOT:PSS/Carbon Nanocoils-Poly(vinyl) Alcohol Films.

The wearable and self-powered sensors with multiple functions are urgently needed for energy saving devices, economical convenience, and artificial human skins. It is a meaningful idea to convert excess heat sources into power supplies for wearable sensors. In this report, we have fabricated a series of free-standing self-powered temperature-strain dual sensors based on poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS)/carbon nanocoils (CNCs)-poly(vinyl) alcohol composite films by a simple drop casting method. The Seebeck coefficients of the composite films were measured to be 19 μV/K. The sensor, with the addition of CNCs, showed a superior sensing performance to that without CNCs. PEDOT:PSS is used to provide a thermoelectric power to detect temperature changes and strain deformations. The minimum detect limit for the temperature difference was 0.3 K. Under a constant temperature gradient of 30 K, strains from 1 to 10% were detected without any external power supply. The films can be easily made into an array to detect the temperature of the fingers and motions of the wrist by attaching it to the human wrist directly. For the first time, due to the independent action of the thermoelectric material and strain sensing material, the thermoelectric voltage which is generated by a constant temperature difference is maintained under different strains. This kind of free-standing self-powered multifunctional sensors has great application prospects in the fields of healthcare and artificial intelligence in the future.

Completeness of the Gaia-verse – IV. The astrometry spread function of Gaia DR2

ABSTRACT Gaia Data Release 2 (DR2) published positions, parallaxes, and proper motions for an unprecedented 1331 909 727 sources, revolutionizing the field of Galactic dynamics. We complement this data with the astrometry spread function (ASF), the expected uncertainty in the measured positions, proper motions, and parallax for a non-accelerating point source. The ASF is a Gaussian function for which we construct the 5D astrometric covariance matrix as a function of position on the sky and apparent magnitude using the Gaia DR2 scanning law and demonstrate excellent agreement with the observed data. This can be used to answer the question ‘What astrometric covariance would Gaia have published if my star was a non-accelerating point source?’. The ASF will enable characterization of binary systems, exoplanet orbits, astrometric microlensing events, and extended sources that add an excess astrometric noise to the expected astrometry uncertainty. By using the ASF to estimate the unit weight error of Gaia DR2 sources, we demonstrate that the ASF indeed provides a direct probe of the excess source noise. We use the ASF to estimate the contribution to the selection function of the Gaia astrometric sample from a cut on astrometric_sigma5d_max showing high completeness for G &amp;lt; 20 dropping to ${\lt} 1{{\ \rm per\ cent}}$ in underscanned regions of the sky for G = 21. We have added an ASF module to the python package scanninglaw (https://github.com/gaiaverse/scanninglaw) through which users can access the ASF.

Exploring a link between the Middle Eocene Climatic Optimum and Neotethys continental arc flare-up

Abstract. The Middle Eocene Climatic Optimum (MECO), a ∼500 kyr episode of global warming that initiated at ∼ 40.5 Ma, is postulated to be driven by a net increase in volcanic carbon input, but a direct source has not been identified. Here we show, based on new and previously published radiometric ages of volcanic rocks, that the interval spanning the MECO corresponds to a massive increase in continental arc volcanism in Iran and Azerbaijan. Ages of Eocene igneous rocks in all volcanic provinces of Iran cluster around 40 Ma, very close to the peak warming phase of the MECO. Based on the spatial extent and volume of the volcanic rocks as well as the carbonaceous lithology in which they are emplaced, we estimate the total amount of CO2 that could have been released at this time corresponds to between 1052 and 12 565 Pg carbon. This is compatible with the estimated carbon release during the MECO. Although the uncertainty in both individual ages, and the spread in the compilation of ages, is larger than the duration of the MECO, a flare-up in Neotethys subduction zone volcanism represents a plausible excess carbon source responsible for MECO warming.

Surface-Modified Highly Biocompatible Bacterial-poly(3-hydroxybutyrate-co-4-hydroxybutyrate): A Review on the Promising Next-Generation Biomaterial.

Polyhydroxyalkanoates (PHAs) are bacteria derived bio-based polymers that are synthesised under limited conditions of nutritional elements with excess carbon sources. Among the members of PHAs, poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [(P(3HB-co-4HB)] emerges as an attractive biomaterial to be applied in medical applications owing to its desirable mechanical and physical properties, non-genotoxicity and biocompatibility eliciting appropriate host tissue responses. The tailorable physical and chemical properties and easy surface functionalisation of P(3HB-co-4HB) increase its practicality to be developed as functional medical substitutes. However, its applicability is sometimes limited due to its hydrophobic nature due to fewer bio-recognition sites. In this review, we demonstrate how surface modifications of PHAs, mainly P(3HB-co-4HB), will overcome these limitations and facilitate their use in diverse medical applications. The integration of nanotechnology has drastically enhanced the functionality of P(3HB-co-4HB) biomaterials for application in complex biological environments of the human body. The design of versatile P(3HB-co-4HB) materials with surface modifications promise a non-cytotoxic and biocompatible material without inducing severe inflammatory responses for enhanced effective alternatives in healthcare biotechnology. The enticing work carried out with P(3HB-co-4HB) promises to be one of the next-generation materials in biomedicines which will facilitate translation into the clinic in the future.

Geological storage capacity for green excess energy readily available in Germany

Abstract. Energy supply in Germany is subject to a profound change. The present paper addresses the German potential of storing excess energy from renewable power sources in the geological subsurface. Wind and solar electricity can be transformed into hydrogen, and with carbon dioxide subsequently into methane. When needed, electricity is regained in a gas turbine power plant combusting the methane. Here, we are taking into account the actual German storage capacity for natural gas and show that the outlined technology is ready for operation and economically competitive. The current potential for combined storage of methane and carbon dioxide allows to store around 80 TWh renewable excess energy. This is far more than required to date and estimated to provide the entire coverage in 2050.

Unconventional Excess Heat Sources for District Heating in a National Energy System Context

District heating (DH) is an important technology in future smart energy systems as it allows for an efficient implementation of various renewable energy sources. As DH develops towards lower temperatures and renewable electricity production increases, new types of heat sources become relevant. Thus, the aim of this article is to assess the potential for utilizing four unconventional excess heat (UEH) sources in DH systems, namely: Data centers, wastewater treatment, metros and service sector buildings. The main method used to assess the UEH potentials is an energy system analysis focusing on the availability and economic feasibility of utilizing the UEH sources in national contexts. The analysis consists of 2015 and 2050 scenarios for Germany, Spain and France. The results show a potential for utilizing the UEH potentials in all three countries, both in 2015 and 2050 systems. The potentials are highest in the 2050 scenarios, primarily due to larger DH shares. Furthermore, the potentials are limited by competition with other heat supply sources, conjunction with heat demands and feasible heat pump operation. In conclusion, the four UEH sources could impact the local DH systems, but in a national energy system context they are expected to play a minor role.

Multi-objective optimization for an integrated renewable, power-to-gas and solid oxide fuel cell/gas turbine hybrid system in microgrid

Power-to-gas (P2G) using excess renewable sources is an effective method to reduce renewable curtailment issues in microgrid system. The produced hydrogen is versatile green fuel for different energy sectors, such as electricity, heat and mobility. In recent researches, fuel cell-based system is considered as a promising technology to consume hydrogen (H2) generated from P2G due to high efficiency and cleanness. However, its economic and thermodynamic adaptability when coupled with intermittent renewable sources remains an open question to be addressed carefully. One of the major challenges in optimizing such system is to simultaneously capture the intraday and seasonal variation of renewable sources & load, as well as the internal thermodynamic process of critical components in appropriate modeling detail. This paper presents a multi-energy system for microgrid in which a wind-powered P2G is coupled with a detailed thermoeconomic model of solid oxide fuel cell/gas turbine (SOFC/GT) hybrid system. A two-level multi-objective optimization of planning and operation together is proposed. For system planning, the optimal balance between the least wind curtailment rate and total life cycle cost (LCC) is determined. To facilitate the coordinate operation of system components, a power management strategy is proposed in response to fluctuations of wind power and electricity load with considerations of multiple thermodynamic safety criteria. Results show that in the selected case, the multi-energy system operates with low wind curtailment rate of 0.63% and high renewable penetration level of 90.1%. The optimized LCC of multi-energy system is £2,468,093 with wind power accounting for 68.35% of total capital investment. With the power management strategy applied, the SOFC/GT could operate under the maximum electrical efficiency of 67.1% with safety constraints satisfied, making up only half investment cost of P2G. To capture seasonal variations, both winter and summer scenarios are detailly analyzed, sensitivity analysis is also carried out to evaluate the interaction between capacities of MES components.

Towards highly efficient electrochemical CO2 reduction: Cell designs, membranes and electrocatalysts

An increase in atmospheric CO2 concentration is directly associated with the rising concerns of climate change and energy issues. The development of effective technologies for capture and utilization of atmospheric CO2 is required to mitigate these global challenges. Electrochemical CO2 reduction (eCO2R) is one of the most promising approaches for the conversion of excess renewable energy sources into storable fuels and value-added chemicals. This field has recently advanced enormously with impressive research achievements aiming at bringing the technology on the brink of commercial realization. Herein, we present a comprehensive review analyzing the recent progress and opportunities of using different cell designs with the main focus on membrane-based flow cells for eCO2R, along with the required system-level strategies for optimal engineering to enhance electrocatalytic selectivity and efficiency. Research advance on the use of different polymer electrolyte membranes for CO2 electrolyzers is updated. Main achievements in new catalyst discoveries are assessed in terms of activity, selectivity, stability together with CO2R reaction kinetics. This was supported by the analysis of the computational studies performed to devise the effective catalyst design routes and to understand the pathways for CO2Rs. The interactive effect of the design of reactors and gas diffusion electrodes with catalysts is analyzed for different operating conditions (like pH, temperature and pressure) of CO2 electrolyzers. Finally, an outlook on future research directions in terms of material and process design for a breakthrough in eCO2R technologies is provided.

Atmospheric residence times and excess of unsupported 210Po in aerosol samples from the Kuwait bay-northern gulf

The concentration of cosmogenic radionuclide 7Be and the naturally occurring radionuclide 222Rn and its progenies 210Pb, 210Po, and 214Pb were measured in the ground surface air in the urban area of the northern Arabian Gulf close to Kuwait Bay. A high-volume air sampler connected with a five-stage cascade impactor was used to collect approximately 1800 cubic meter weekly for a period of one year. The concentrations of 210Pb and 210Po varied from 0.35 to 1.65 mBq m−3 and from 0.23 to 3.2 mBq m−3, respectively; the 210Po/210Pb activity ratio was close to one. The average concentration of 7Be was 6.24 mBq m−3, ranging from 3 to 10 mBq m−3. The temporal variations of 210Pb, 210Po and 7Be showed maximum concentrations of 210Po and 7Be in occurred summer months. The observed excess of 210Po concentrations can be attributed to the local and long-range transport of suspended dust with 210Pb and 210Po in radioactive equilibrium state, oil industry emissions, local resuspended dust and the sea-salt-aerosols from the Arabian Gulf. The range of the residence time estimation using the 222Rn/210Pb and 214Pb/210Pb activity ratio methods ranged from three to five days. Moreover, the estimated residence time by the application of 7Be from the activity median aerodynamic diameter method was 4.2 days. The method of using the 210Po/210Pb activity ratio was invalid because of the excess 210Po sources of anthropogenic origin. Therefore, extensive accurate diurnal measurements of 214Pb and 222Rn can be applied in hot arid regions for better aerosols residence time estimation.

Recycle of silicon slurry cutting waste to prepare high purity SiC by salt-assisted carbothermic reduction

A technological route for recycling silicon slurry cutting waste (SSCW) as silicon source to prepare high purity silicon carbide as well as reducing the industry cost and avoiding the environmental pollution aroused by the waste was explored. The effect of Fe2O3, NaCl addition and smelting temperature on production of high quality SiC were studied. The existence of Fe element acts like a catalyst and contributes to the synthesis of SiC at relatively low temperatures (1550 °C). The excess of Fe element in the SSCW, however, would inhibit further improvement of the purity of the SiC product since Fe element would remain in the final product as Si–Fe alloy. Slight addition of salt was also verified to be positive for the improvement of SiC yield and purity. SiC product with a purity of more than 93 wt% was obtained after acid leaching for the removal of Fe impurity and under the optimized conditions as NaCl addition of 7 wt% and smelting temperature of 1850 °C. The thermodynamic analysis shows that a series of intermediate gas products (CO, SiO, SiO2) have been generated and taken an important role in the synthesis of SiC and excess carbon source is necessary for promoting the utilization of the SSCW since it can efficiently contribute to the formation of SiC and the intermediate products namely SiO and CO. The nucleation mechanism analysis indicates that both the original size and morphology of the carbon source and SiC particles have great influence on the forming particle size and morphology of the generated SiC since both can act as a nucleation center for a certain amount of SiC which is verified by the SEM analysis.

Blind Measurement of Receiver System Noise.

Tightly packaged receivers pose a challenge for noise measurements. Their only outputs are often diagnostic or benchmark information-"user data" that result from unknown processing. These include data rate test results, signal-to-noise ratio estimated by the receiver, and so on. Some of these are important gauges of communication viability that may be enshrined in performance and conformance specifications. Engineers can estimate these parameters based on standards and simplified system models, but there are few means to validate against physical measurements. We propose here a set of measurement techniques to complement and support models of system noise. The approach is founded on a semiparametric model of the noise response of a full-stack receiver. We probe this response experimentally by systematically perturbing signals and excess noise levels at the receiver input. The resulting technique is blind to protocol and implementation details. We introduce the design and implementation of some novel test capabilities required for these tests: a precision programmable excess noise source and a highly directive programmable attenuator. We also introduce a regression procedure to estimate system noise (or NF) from the controlled input conditions and summary statistics of the user data output. We also estimate uncertainty in the measurement by combining traditional methods with a Monte Carlo method that propagates random errors through the regression. Case studies demonstrate the measurement with consumer wireless networking and geolocation equipment. These include verification by repeatability testing and cross-comparison against Y-factor measurements.

Tectonic stress controls saucer-shaped sill geometry and emplacement mechanism

AbstractSaucer-shaped sills are common in sedimentary basins worldwide. The saucer shape relates to asymmetric sill-tip stress distributions during intrusion caused by bending of the overburden. Most saucer-shaped sill models are constructed using a magma-analogue excess source pressure (Po) to drive host-rock failure, but without tectonic stress. Here we present axisymmetric finite-element simulations of radially propagating sills for a range of tectonic stress (σr) conditions, from horizontal tension (σr &amp;lt; 0) to horizontal compression (0 &amp;lt; σr). Response to σr falls into four regimes, based on sill geometry and failure mode of the host rock. The regimes are considered in terms of the ratio of tectonic stress versus magma source pressure R = σr/Po: (I) initially seeded sills transition to a dike during horizontal extension (R &amp;lt; 0); (II) with R increasing from 0 towards 1 (compressive σr), sill base length increases and sill incline decreases; (III) where 1 &amp;lt; R &amp;lt; 2, sill base length relatively decreases and sill incline increases; and (IV) where R &amp;gt; 2, sills grow as inclined sheets. Sills in regimes I–III grow dominantly by tensile failure of the host rock, whereas sills in regime IV grow by shear failure of the host rock. Varying σr achieves a range of sill geometries that match natural sill profiles. Tectonic stress therefore represents a primary control on saucer-shaped sill geometry and emplacement mechanism.

Optimization of volume-limited thermal energy storage in non-continuous processes

Due to the nature of non-continuous processes, heat recovery through direct heat integration is limited. Thermal energy storage (TES) is usually employed for indirect heat transfer, provided excess heat sources and sinks are available. Such processes may have brief peaks in energy demand, necessitating large TES. However, practical space constraints often limit maximal storage volumes, restricting the potential for heat recovery. This paper aims to develop a linear programming optimization model to determine the storage integration solutions which maximize heat recovery per batch for volume-limited sensible stratified storage. Indirect source and sink profiles are used to determine maximum process heat recovery and subsequently the initial TES capacity. The results produce a process-specific capacity limitation chart of batch-wise maximal heat recovery, allowing generation of optimal storage loading and unloading profiles. The optimization model was applied to two case studies. The resulting capacity limitation chart shows that a stratified storage, with a volume of total 96m3 is needed to achieve 100% of the trageted direct and indirect heat recovery. Approximately 60% heat recovery can already be achieved by using only a 4m3 storage. The model is extended to a fixed temperature variable mass storage with multiple VSUs.

The effect of different parameters of the excess heat source on the levelized cost of excess heat

In areas with higher heat demand densities, district heating is the most logical way of achieving heat sector decarbonisation aims, especially when renewable energy or highly efficient cogeneration is used. However, excess heat from industry is also recognized as a valuable source with the high potential for utilization. It increases the economic and environmental viability of the system due to the low operation, investment and conventional energy costs. The main goal of this work was to define the effect of the main factors influencing the levelized cost of excess heat. The paper provided the feasibility of excess heat utilization in different district heating configurations, including solar collectors, cogeneration, peak load boilers, heat pumps and heat storages, showing that its overall utilization can be much lower than the expected 100% of the overall availability depending on the configuration. Furthermore, temperature levels of the excess heat source have been considered in the analysis to show changes in levelized cost of excess heat with different temperatures and the necessary preconditions for its utilization. It has been concluded that it is necessary to reduce the supply temperature of district heating in order to make the low temperature excess heat sources feasible.