Energetic Impact Research Articles

The Multiple Functions of Common Microbial Carbon Polymers, Glycogen and PHB, during Stress Responses in the Non-Diazotrophic Cyanobacterium Synechocystis sp. PCC 6803.

Classical microbial carbon polymers such as glycogen and polyhydroxybutyrate (PHB) have a crucial impact as both a sink and a reserve under macronutrient stress conditions. Most microbial species exclusively synthesize and degrade either glycogen or PHB. A few bacteria such as the phototrophic model organism Synechocystis sp. PCC 6803 surprisingly produce both physico-chemically different polymers under conditions of high C to N ratios. For the first time, the function and interrelation of both carbon polymers in non-diazotrophic cyanobacteria are analyzed in a comparative physiological study of single- and double-knockout mutants (ΔglgC; ΔphaC; ΔglgC/ΔphaC), respectively. Most of the observed phenotypes are explicitly related to the knockout of glycogen synthesis, highlighting the metabolic, energetic, and structural impact of this process whenever cells switch from an active, photosynthetic ‘protein status’ to a dormant ‘glycogen status’. The carbon flux regulation into glycogen granules is apparently crucial for both phycobilisome degradation and thylakoid layer disassembly in the presence of light. In contrast, PHB synthesis is definitely not involved in this primary acclimation response. Moreover, the very weak interrelations between the two carbon-polymer syntheses indicate that the regulation and role of PHB synthesis in Synechocystis sp. PCC 6803 is different from glycogen synthesis.

Keeping Cool with Hot Stuff: Safe Collection, Transport and Recycling of Lithium Batteries

With advanced development, e.g. in the field of information technology, telecommunication and e-mobility, the use of lithium batteries is constantly growing and will continue to grow even more during the years to come. Due to their chemical composition and their high energy content, lithium batteries must be handled safely in order to avoid possible hazards. In the context of extended producer responsibility and the taking back of waste lithium batteries this poses a particular challenge for storage, transport and recycling processes. Objective: The strict regulatory framework in Europe sets high standards for the transport (ADR) and recycling (European Battery Directive) of waste lithium batteries. As Europe’s leading service provider for the taking back of used batteries GRS Batterien’s mission is to provide practical end-to-end solutions to its 170,000 collection points and to numerous business partners for logistic and recycling services. The aim is to sustain and further improve the proper, safe and compliant battery collection. Results: GRS Batterien has developed and implemented innovative processes and products to address the needs of all actors in the reverse supply chain for the taking back of used lithium batteries. As the first player in the market GRS Batterien introduced a special transport packaging and obtained the required approval from competent authorities, allowing the safe and compliant transport of damaged lithium batteries with a gross mass exceeding 500 g, independently of their type or chemistry. A proprietary calculation model is utilized to simulate the energetic and chemical impact of a thermal runaway based on a worst case scenario. Specially trained and equipped 3PL service providers are acting as qualified carriers for damaged and defective lithium batteries, applying a sophisticated quality control process. As a result, GRS Batterien is able to safely collect, ship and recycle lithium batteries of various types - from small portable batteries via batteries from e-bikes or gardening tools through to industrial batteries from electric vehicles or smart energy storage systems. Conclusions: During the recent few years GRS Batterien's innovations have significantly improved the collection, the transport and the recycling of lithium batteries. However, additional work will be necessary to further simplify the handling of used lithium batteries. GRS Batterien continues to facilitate improvements, e.g. with R&D activities to develop more efficient recycling technologies or with additional services in related areas.

The Painlevé paradox in contact mechanics

The 120-year old so-called Painleve paradox involves the loss of determinism in models of planar rigid bodies in point contact with a rigid surface, subject to Coulomb-like dry friction. The phenomenon occurs due to coupling between normal and rotational degrees-of-freedom such that the effective normal force becomes attractive rather than repulsive. Despite a rich literature, the forward evolution problem remains unsolved other than in certain restricted cases in 2D with single contact points. Various practical consequences of the theory are revisited, including models for robotic manipulators, and the strange behaviour of chalk when pushed rather than dragged across a blackboard. Reviewing recent theory, a general formulation is proposed, including a Poisson or energetic impact law. The general problem in 2D with a single point of contact is discussed and cases or inconsistency or indeterminacy enumerated. Strategies to resolve the paradox via contact regularisation are discussed from a dynamical systems point of view. By passing to the infinite stiffness limit and allowing impact without collision, inconsistent and indeterminate cases are shown to be resolvable for all open sets of conditions. However, two unavoidable ambiguities that can be reached in finite time are discussed in detail, so called dynamic jam and reverse chatter. A partial review is given of 2D cases with two points of contact showing how a greater complexity of inconsistency and indeterminacy can arise. Extension to fully three-dimensional analysis is briefly considered and shown to lead to further possible singularities. In conclusion, the ubiquity of the Painleve paradox is highlighted and open problems are discussed.

Crater production by energetic nanoparticle impact on Au nanofoams

Impact of energetic nanoparticles on solids produces craters on the surface. We use molecular dynamics simulations to compare crater production on a compact Au solid with that in a porous (foam) target. Our results show a complex picture: (i) At low impact velocities, the nanoparticles produce permanent craters in the foam while they cannot penetrate the compact target. (ii) With increasing velocity and/or projectile mass, the crater depth in the foam target increases less strongly than for the compact target. The plasticity-affected zone in the foam target is of similar size as in the compact target. Our results are relevant for the use of porous structures as shields against nanoparticle impact.

Atmospheric pressure gas chromatography quadrupole-time-of-flight mass spectrometry for simultaneous determination of fifteen organochlorine pesticides in soil and water

In this study, the application of atmospheric pressure gas chromatography quadrupole-time-of-flight mass spectrometry (APGC-QTOF-MS) has been investigated for simultaneous determination of fifteen organochlorine pesticides in soil and water. Soft ionization of atmospheric pressure gas chromatography was evaluated by comparing with traditional more energetic electron impact ionization (EI). APGC-QTOF-MS showed a sensitivity enhancement by approximately 7–305 times. The QuEChERs (Quick, Easy, Cheap, Effective, Rugged, and Safe) method was used to pretreat the soil samples and solid phase extraction (SPE) cleanup was used for water samples. Precision, accuracy and stability experiments were undertaken to evaluate the feasibility of the method. The results showed that the mean recoveries for all the pesticides from the soil samples were 70.3–118.9% with 0.4–18.3% intra-day relative standard deviations (RSD) and 1.0–15.6% inter-day RSD at 10, 50 and 500μg/L levels, while the mean recoveries of water samples were 70.0–118.0% with 1.1–17.8% intra-day RSD and 0.5–12.2% inter-day RSD at 0.1, 0.5 and 1.0μg/L levels. Excellent linearity (0.9931≦r2≤0.9999) was obtained for each pesticides in the soil and water matrix calibration curves within the range of 0.01–1.0mg/L. The limits of detection (LOD) for each of the 15 pesticides was less than 3.00μg/L, while the limit of quantification (LOQ) was less than 9.99μg/L in soil and water. Furthermore, the developed method was successfully applied to monitor the targeted pesticides in real soil and water samples.

Energetic and Economic Impact of Using Bioclimatic Design Technics and of Solar Water Preheating System Integration on Tertiary Building

In this paper, a real case study about energy efficiency improvement of the building of the Software and Services Development Companies' Space at the Technological Center of 'EL GHAZALA' is presented. On the one hand, this study aims to highlight the importance of the energetic and financial gains realized upon the respect of some bioclimatic design rules and solar water preheating system integration. It also aims to present the Tunisian thermal regulation limits. On the other hand, it provides a method for the design of glazed surfaces and overhangs or fins while introducing the way to use the SOLO and CLIP software for the energetic and financial gains calculation. In a first step, building thermal needs were studied, using the CLIP software, for two specific cases: a first case where the building is under the most common standard conditions in Tunisia and where only glazed surfaces dimensions and orientations are optimized; and a second case where higher performance materials and overhangs and fins are used. It came out that half of the thermal energy needs could be saved and low investment payback of about nine years could be reached. Another outcome is that Tunisian thermal regulation should be updated in order to further promote the use of more efficient building materials. Then, in a second step, the effect of solar water preheating system integration was studied using the SOLO software. It turned out that its integration could cover about 64% of the building's heating needs.

Comet 67P/Churyumov-Gerasimenko: Constraints on its origin from OSIRIS observations

One of the main aims of the ESA Rosetta mission is to study the origin of the solar system by exploring comet 67P/Churyumov-Gerasimenko at close range. In this paper we discuss the origin and evolution of comet 67P/Churyumov-Gerasimenko in relation to that of comets in general and in the framework of current solar system formation models. We use data from the OSIRIS scientific cameras as basic constraints. In particular, we discuss the overall bi-lobate shape and the presence of key geological features, such as layers and fractures. We also treat the problem of collisional evolution of comet nuclei by a particle-in-a-box calculation for an estimate of the probability of survival for 67P/Churyumov-Gerasimenko during the early epochs of the solar system. We argue that the two lobes of the 67P/Churyumov-Gerasimenko nucleus are derived from two distinct objects that have formed a contact binary via a gentle merger. The lobes are separate bodies, though sufficiently similar to have formed in the same environment. An estimate of the collisional rate in the primordial, trans-planetary disk shows that most comets of similar size to 67P/Churyumov-Gerasimenko are likely collisional fragments, although survival of primordial planetesimals cannot be excluded. A collisional origin of the contact binary is suggested, and the low bulk density of the aggregate and abundance of volatile species show that a very gentle merger must have occurred. We thus consider two main scenarios: the primordial accretion of planetesimals, and the re-accretion of fragments after an energetic impact onto a larger parent body. We point to the primordial signatures exhibited by 67P/Churyumov-Gerasimenko and other comet nuclei as critical tests of the collisional evolution.

Structural and Energetic Impact of Non-Natural 7-Deaza-8-Azaadenine and Its 7-Substituted Derivatives on H-Bonding Potential with Uracil in RNA Molecules.

Non-natural (synthetic) nucleobases, including 7-ethynyl- and 7-triazolyl-8-aza-7-deazaadenine, have been introduced in RNA molecules for targeted applications, and have been characterized experimentally. However, no theoretical characterization of the impact of these modifications on the structure and energetics of the corresponding H-bonded base pair is available. To fill this gap, we performed quantum mechanics calculations, starting with the analysis of the impact of the 8-aza-7-deaza modification of the adenine skeleton, and we moved then to analyze the impact of the specific substituents on the modified 8-aza-7-deazaadenine. Our analysis indicates that, despite of these severe structural modifications, the H-bonding properties of the modified base pair gratifyingly replicate those of the unmodified base pair. Similar behavior is predicted when the same skeleton modifications are applied to guanine when paired to cytosine. To stress further the H-bonding pairing in the modified adenine-uracil base pair, we explored the impact of strong electron donor and electron withdrawing substituents on the C7 position. Also in this case we found minimal impact on the base pair geometry and energy, confirming the validity of this modification strategy to functionalize RNAs without perturbing its stability and biological functionality.

A hybrid scheme for simulation of planar rigid bodies with impacts and friction using impact mappings

This paper introduces numerical techniques necessary for the implementation of impact maps derived from an energetic impact law for rigid-body impacts with friction at isolated contact points. In particular the work focuses on methodologies for long-term simulation with behaviours such as dynamic transitions and chatter. The methods are based on hybrid event-driven numerical solvers for ordinary differential equations together with system states to deal with the transitions. A slender rod impacting a periodically oscillating surface is used as an example to illustrate implementation and methods. The numerical scheme for the rod system is used to show how symmetry can play an important role in the presence of friction for long-term dynamics. This will show that surface oscillations with low frequencies tend to lead to periodic motions of the rod that are independent of friction. For higher frequencies however the periodic solutions are not that common and irregular motion ensues.

DNA sequencing with MspA: Molecular Dynamics simulations reveal free-energy differences between sequencing and non-sequencing mutants.

MspA has been identified as a promising candidate protein as a component of a nanopore-based DNA-sequencing device. However the wildtype protein must be engineered to incorporate all of the features desirable for an accurate and efficient device. In the present study we have utilized atomistic molecular dynamics to perform umbrella-sampling calculations to calculate the potential of mean force (PMF) profiles for translocation of the four DNA nucleotides through MspA. We show there is an energetic barrier to translocation of individual nucleotides through a mutant that closely resembles the wildtype protein, but not through a mutant engineered for the purpose of sequencing. Crucially we are able to quantify the change in free energy for mutating key residues. Thus providing a quantitative characterisation of the energetic impact of individual amino acid sidechains on nucleotide translocation through the pore of MspA.

Melting and mixing states of the Earth's mantle after the Moon-forming impact

The Earth's Moon is thought to have formed by an impact between the Earth and an impactor around 4.5 billion years ago. This impact could have been so energetic that it could have mixed and homogenized the Earth's mantle. However, this view appears to be inconsistent with geochemical studies that suggest that the Earth's mantle was not mixed by the impact. Another outcome of the impact is that this energetic impact melted the whole mantle, but the extent of mantle melting is not well understood even though it must have had a significant effect on the subsequent evolution of the Earth's interior and atmosphere. To understand the initial state of the Earth's mantle, we perform giant impact simulations using smoothed particle hydrodynamics (SPH) for three different models: (a) standard: a Mars-sized impactor hits the proto-Earth, (b) fast-spinning Earth: a small impactor hits a rapidly rotating proto-Earth, and (c) sub-Earths: two half Earth-sized planets collide. We use two types of equations of state (MgSiO3 liquid and forsterite) to describe the Earth's mantle. We find that the mantle remains unmixed in (a), but it may be mixed in (b) and (c). The extent of mixing is most extensive in (c). Therefore, (a) is most consistent and (c) may be least consistent with the preservation of the mantle heterogeneity, while (b) may fall between. We determine that the Earth's mantle becomes mostly molten by the impact in all of the models. The choice of the equation of state does not affect these outcomes. Additionally, our results indicate that entropy gains of the mantle materials by a giant impact cannot be predicted well by the Rankine–Hugoniot equations. Moreover, we show that the mantle can remain unmixed on a Moon-forming timescale if it does not become mixed by the impact.

Ultrafast physical sputtering of GaN by electrosprayed nanodroplet beams

GaN is a wide-bandgap semiconductor used for light-emitting diodes, laser diodes, UV detectors, power electronics, and microelectromechanic devices. Etching is a key step in the fabrication of these devices, but it is difficult and slow due to the chemical stability and the strong interatomic bonds that make GaN a superior material over the industry-standard Si. Reactive ion etching by high density plasmas, with a maximum etching rate of 1300nm/min, is the process of choice for GaN. This letter presents a novel and faster etching method based on the bombardment by electrosprayed nanodroplets. The energetic impact of these projectiles ejects atoms by physical sputtering and, under the non-optimized beams conditions employed in our research, demonstrates etching rates on GaN as high as 1745nm/min and sputtering yields in excess of 25 atoms per projectile’s molecule.

Impact of thymine glycol damage on DNA duplex energetics: Correlations with lesion-induced biochemical and structural consequences.

The magnitude and nature of lesion-induced energetic perturbations empirically correlate with mutagenicity/cytotoxicity profiles and can be predictive of lesion outcomes during polymerase-mediated replication in vitro. In this study, we assess the sequence and counterbase-dependent energetic impact of the Thymine glycol (Tg) lesion on a family of deoxyoligonucleotide duplexes. Tg damage arises from thymine and methyl-cytosine exposure to oxidizing agents or radiation-generated free-radicals. The Tg lesion blocks polymerase-mediated DNA replication in vitro and the unrepaired site elicits cytotoxic lethal consequences in vivo. Our combined calorimetric and spectroscopic characterization correlates Tg -induced energetic perturbations with biological and structural properties. Specifically, we incorporate a 5R-Tg isomer centered within the tridecanucleotide sequence 5'-GCGTACXCATGCG-3' (X = Tg or T) which is hybridized with the corresponding complementary sequence 5'-CGCATGNGTACGC-3' (N = A, G, T, C) to generate families of Tg -damaged (Tg ·N) and lesion-free (T·N) duplexes. We demonstrate that the magnitude and nature of the Tg destabilizing impact is dependent on counterbase identity (i.e., A ∼ G < T < C). The observation that a Tg lesion is less destabilizing when positioned opposite purines suggests that favorable counterbase stacking interactions may partially compensate lesion-induced perturbations. Moreover, the destabilizing energies of Tg ·N duplexes parallel their respective lesion-free T·N mismatch counterparts (i.e., G < T < C). Elucidation of Tg-induced destabilization relative to the corresponding undamaged mismatch energetics allows resolution of lesion-specific and sequence-dependent impacts. The Tg-induced energetic perturbations are consistent with its replication blocking properties and may serve as differential recognition elements for discrimination by the cellular repair machinery.

Nanoparticle release quantification during weak and intense dry dispersion of nanostructured powders

Currently, the characterisation of particle release from nanostructured powders is realised based on different release scenarios, which were typically designed to describe real powder handling processes. Most of these scenarios base on short term stress situations (e.g. drop down, mixing) and are thus accompanied with dynamic changes of the particle number concentration, which complicates both the process characterisation and the release characterisation. In this study, two continuous release processes for weak and intense dispersion of powder agglomerates were analysed based on considerations regarding energetic and instrumental impact.

Growth of Mn-doped ZnO thin films by rf-sputter deposition and lattice relaxation by energetic ion impact

We have grown Mn-doped ZnO (MZO) thin films on SiO2–glass, sapphire (Al2O3) and MgO (001) substrates for the substrate temperature (Ts) from room temperature (RT) to 550°C, by using a radio-frequency (rf)-magnetron sputter deposition (off-axis) method with a Zn1−xMnxO (x≈0.05) sintered target. X-ray diffraction (XRD) shows that MZO films are polycrystalline with hexagonal structure and have exceptionally a-axis predominant orientation for MgO at Ts above 400°C, (110) on r-plane-cut Al2O3 at Ts above 150°C and c-axis orientation otherwise. According to Rutherford backscattering spectroscopy (RBS) of 1.8MeV He ions, Mn/Zn is 6% and the composition is nearly stoichiometric. MZO films have high resistivity (∼1MΩcm) and paramagnetism. It is found that for MZO films on SiO2, the XRD intensity decreases with increasing the deviation of lattice parameter of thin films from the bulk value. Optical properties and observations of lattice relaxation and resistivity modification by energetic ion impact are also described.

Influence of Power Supply Energy Characteristics upon the Stability of MMA Process

The paper provides the results of experimental study of how the technological characteristics (amount of spatter, stability of the welding process) of manual metal arc welding (MMA) depend upon power supplies providing various kinds of energetic impact upon the electrode metal (inverter power supply, diode rectifier). It was established that inverter power supplies (as they reduce peak loading) provide better quality of welds (more stable process, lower amount of spatter) and this reduces the fabrication cost due to the reduction of deseaming operations, lower welding material consumption as well as improving the service reliability of the welding constructions.

Assessing the Energetic and Environmental Impacts of the Operation and Maintenance of Spanish Sewer Networks from a Life-Cycle Perspective

The environmental impacts resulting from sewer networks are best analysed from a life-cycle perspective to integrate the energy requirements into the infrastructure design. The energy requirements for pumping wastewater depend on the configuration of the city (e.g., climate, population, length of the sewer, topography, etc.). This study analyses and models the effect of such site-specific features on energy consumption and related effects in a sample of Spanish cities. The results show that the average annual energy used by sewers (6.4 kWh/capita and 0.014 kWh/m3 of water flow) must not be underestimated because they may require up to 50 % of the electricity needs of a typical treatment plant in terms of consumption per capita. In terms of Global Warming Potential, pumping results in an average of 2.3 kg CO2eq./capita. A significant positive relationship was demonstrated between the kWh consumed and the length of the sewer and between other factors such as the population and wastewater production. In addition, Atlantic cities can consume 5 times as much energy as Mediterranean or Subtropical regions. A similar trend was shown in coastal cities. Finally, a simple predictive model of the electricity consumption was presented that considers the analysed parameters.

Vocal performance affects metabolic rate in dolphins: implications for animals communicating in noisy environments.

Many animals produce louder, longer or more repetitious vocalizations to compensate for increases in environmental noise. Biological costs of increased vocal effort in response to noise, including energetic costs, remain empirically undefined in many taxa, particularly in marine mammals that rely on sound for fundamental biological functions in increasingly noisy habitats. For this investigation, we tested the hypothesis that an increase in vocal effort would result in an energetic cost to the signaler by experimentally measuring oxygen consumption during rest and a 2 min vocal period in dolphins that were trained to vary vocal loudness across trials. Vocal effort was quantified as the total acoustic energy of sounds produced. Metabolic rates during the vocal period were, on average, 1.2 and 1.5 times resting metabolic rate (RMR) in dolphin A and B, respectively. As vocal effort increased, we found that there was a significant increase in metabolic rate over RMR during the 2 min following sound production in both dolphins, and in total oxygen consumption (metabolic cost of sound production plus recovery costs) in the dolphin that showed a wider range of vocal effort across trials. Increases in vocal effort, as a consequence of increases in vocal amplitude, repetition rate and/or duration, are consistent with behavioral responses to noise in free-ranging animals. Here, we empirically demonstrate for the first time in a marine mammal, that these vocal modifications can have an energetic impact at the individual level and, importantly, these data provide a mechanistic foundation for evaluating biological consequences of vocal modification in noise-polluted habitats.

High-Throughput Quantification of the Impact of Different Osmolytes on the Thermal Stability of DNA

Small molecules (osmolytes) are known to either stabilize or destabilize proteins/nucleotides depending on the concentrations and/or solvent conditions. The presence of different molecules and ions in the surrounding medium affects the stability of DNA in solution. In this work, we have developed a High-Throughput method for quantifying the energetic impact of addition of various osmolytes on short DNA duplexes. Six 19-base pair, non-self-complementary duplex DNA oligomers along with a 16-base pair control duplex DNA, having varied GC-content (ranging from 16% to 79%), nearest neighbors and end sequences were used. We sampled thirteen different osmolytes that are common in humans and throughout nature by covering different chemical classes including, sugars, polyols, amino acids, and methylamines. Varying concentrations of these osmolytes (from 0.5 M up to 3.0 M) were examined for their effects on these duplexes. Experiments were performed in 384-well plates that were prepared using a robotic device, which was calibrated for the correct dispense volume for different components of the plate. Temperature-induced melting transitions monitored by fluorescence were measured for these duplexes and the Tm values along with the m-values and melting transition enthalpies were determined. Conventional approaches, including Circular Dichroism (CD) were used to verify the thermodynamic parameters. Osmolytes had varied effects on DNA stability, and the (de)stabilizing effect does not necessarily correlate with their effects on proteins. The m-values can drastically depend on the GC-content.

The Energetic Impact of the Lighting System in the Road Tunnels

The quantity of artificial light necessary in a road tunnel depends on the external luminance, the climatic conditions, the road surface wet or dry, the traffic speed, and the related safe driver stopping distance. The design of the lighting system takes into account these parameters, assuming critical conditions. This may result in very high electrical power demand. The authors, based on the experience acquired as a result of some designs made for Italian motorway tunnels, suggest a practical method to estimate the load demand and the annual energy cost for the proposed lighting system. It highlights the impact of the presence of a control system able to improve the safety and comfort for the drivers, avoiding the excesses of luminance and mitigating the energetic cost. The control has to operate and tune automatically the luminous flux emitted by the lighting system according to actual conditions given by the input signals of the external luminance, the climatic condition, and the traffic intensity.