Energy Measurements Research Articles

Inverse source problem for multi-term time-fractional diffusion equation with nonlocal boundary conditions

<abstract><p>In this paper, we consider an inverse source problem with nonlocal boundary conditions for the heat equation involving multi-term time-fractional derivatives. We determine a source term independent of the space variable, and the temperature distribution from the energy measurement. We reduce the solution of the inverse problem to finding solutions to two problems. The well-posedness of each problem is shown using the generalized Fourier method.</p></abstract>

ANALISA PENGGANTIAN KWH METER BERMASALAH TERHADAP EFEKTIFITAS KWH JUAL

Abstract. kWh Meter is a tool used to measure and record the use of electrical energy consumed by customers. However, there are still problematic that occur in the kWh meter caused by several factors such as jammed kWh, blurry kWh and old kWh. This problematic affects the measurement of electrical energy in the kWh meter installed on the customer. The average use of the kWh before being replaced with the average usage after being replaced shows an increase. This shows that there is an anomaly in the changed kWh meter. This Final Report will discuss this matter. The methodology used in this Final Report is the literature method, the observation method, as well as the consultation and discussion method. The author collects data by seeking information from books, articles, internet, and journals related to titles that can support the progress of this final report. The author also made direct observations on objects in the field located in the PT. PLN (Persero) ULP Muara Enim. Then the author conducted discussions with supervisors and PLN staff. The conclusion that can be drawn from this Final Report is that there is an increase in the value of kWh after replacing the problematic kWh meter, which previously the average usage was only 3,282 kWh then after replacing the average usage increased to 4,011 kWh, so there is a difference in the average usage of 729 kWh. The replacement of jammed and blurry kWh meters increases the effectiveness of selling kWh by 22.21%. So there is difference in costs which is a loss that in charge of PT. PLN of Rp. 904.328/month.

ЕФЕКТ АНОМАЛЬНО СИЛЬНОГО ПОГЛИНАННЯ ЕЛЕКТРОМАГНІТНОГО ВИПРОМІНЮВАННЯ ТОНКИМИ ПРОВІДНИКОВИМИ ВОЛОКНАМИ

Subject and Purpose. The effect of abnormally strong interaction of electromagnetic radiation with fine conductive fibers is сonsidered. Metal, semiconductor, or graphite fibers can heavily absorb electromagnetic radiation provided the fiber diameter is several hundred times smaller than the radiation wavelength. For the most effective transfer of radiation energy, a proper ratio of the radiation wavelength, fiber refractive index, and fiber diameter is sought. Methods and Methodology. The diffraction problem of a cylinder whose diameter is much smaller than the incident wavelength is treated. The formulas to compute the radiation absorption efficiency have a series appearance. The series coefficients depend on the diameter of the cylinder, its refractive index, and the wavelength. With the cylinder diameter much smaller than the wavelength, these coefficients can be series expanded in the small parameter, and it should suffice to take into account only the first term. The findings are experimentally verified by measurements of the microwave radiation energy transmitted to a fine graphite fiber. Results. Relationships have been determined of the fiber diameter, fiber conductivity, and wavelength when the effect of the electromagnetic radiation absorption was at its strongest. The experiment showed that even unfocused, an 8 mm wave beam transmitted more than 10% of the energy to a graphite fiber of a 12 μm diameter. The size of the fiber area struck by the beam was 300 times smaller than the beam cross-section. Conclusions. Conductive fibers of a cross-sectional diameter much smaller than the incident radiation wavelength strongly absorb this radiation. The absorption is at its strongest when the radiation wavelength in the fiber substance is approximately 10 times larger than the cross-sectional diameter of the fiber. The effect of the anomalously strong absorption of electromagnetic radiation can be used to transfer the electromagnetic radiation energy to fine-fiber targets no matter whether the radiation beam is focused or not. Also, this effect can be of use for making protective screens in the microwave region.

Особенности формирования слоя положительного заряда при модификации изделий в струе высокочастотного ёмкостного разряда в условиях динамического вакуума

The paper presents a physical description of the formation of a layer of positive charge around the body, during processing in a high-frequency capacitive (HF) discharge, due to which a directed flow of ions arises that bombard the surface of the body being processed. With the help of holographic measurements, the presence of a layer, which differs from the plasma of an RF discharge, is demonstrated around a body placed in an RF plasma. The theoretical substantiation of holographic measurements, plasma potentials, measurements of ion energy and ion current density on the surface of the treated body is presented.

Reaction rate constant: a theoretical description from local temperature.

Application of various descriptors based on electron density and its associated quantities to quantify chemical reactivity within the conceptual density functional theory has recently come into spotlight. Among others and particularly relevant to our study, local temperature based on electron density as well as kinetic energy density, as a measure of the kinetic energy of an electron moving in the Kohn-Sham potential of systems, should be mentioned. In this work, we propose to use the local temperature for describing the reaction rate constant, where our main idea originates from the point that the smaller the local temperature at the reaction center, the easier the electron removal, leading to a larger rate constant. On the basis of theoretical considerations, it is proved that the rate constant variations caused by the substituent effects can well be proportional to the local temperature at the reaction center. In order to numerically validate our proposed approach, we have taken the phenol derivatives with the available experimental rate constants of their O-methylation reaction as working models. The reason for this choice is that one of the most versatile approaches for labeling biologically active compounds with the 11C nuclide for positron emission tomography (PET) is methylation by methyl iodide including 11C nuclide, [11C]MeI, where methylation of phenolic oxygen with [11C]MeI is utilized to label some important tracers for PET studies. Our results unveil that the local temperature changes at the reaction center of the aforementioned reaction are reasonably correlated with the rate constant variations. Hopefully, incorporating the proposed correlations between the local temperature and the kinetics data into a computer control algorithm not only provides a simple tool for predicting the rate constant of the O-methylation reaction for other substituted phenols, but also, as a part of the chemical artificial intelligence, the optimum [11C]MeI labeling conditions for a wide variety of phenol derivatives can be controlled.

Evaluation of the mean excitation energies of gaseous and liquid argon

Current and future experiments need to know the stopping power of liquid argon. It is used directly in calibration, where commonly the minimum-ionizing portion of muon tracks is used as a standard candle. Similarly, muon range is used as a measure of muon energy. More broadly, the stopping power figures into the simulation of all charged particles, and so uncertainty propagates widely throughout data analysis of all sorts. The main parameter that controls stopping power is the mean excitation energy, or I-value. Direct experimental information for argon's I-value come primarily from measurements of gaseous argon, with a very limited amount of information from solid argon, and none from liquid argon. A powerful source of indirect information is also available from oscillator strength distribution calculations. We perform a new calculation and find that from oscillator strength information alone, the I-value of gaseous argon is (187 ± 5) eV. In combination with the direct measurements and other calculations, we recommend (187 ± 4) eV for gaseous argon. For liquid argon, we evaluate the difference in central value and uncertainty incurred by the difference of phase and recommend (197 ± 7) eV. All uncertainties are given to 68% C.L.

Proton Beam Range and Charge Verification Using Multilayer Faraday Collector.

A daily quality assurance (QA) check in proton therapy is ensuring that the range of each proton beam energy in water is accurate to 1 mm. This is important for ensuring that the tumor is adequately irradiated while minimizing damage to surrounding healthy tissue. It is also important to verify the total charge collected against the beam model. This work proposes a time-efficient method for verifying the range and total charge of proton beams at different energies using a multilayer Faraday collector (MLFC). We used an MLFC-128-250 MeV comprising 128 layers of thin copper foils separated by thin insulating KaptonTM layers. Protons passing through the collector induce a charge on the metallic foils, which is integrated and measured by a multichannel electrometer. The charge deposition on the foils provides information about the beam range. Our results show that the proton beam range obtained using MLFC correlates closely with the range obtained from commissioning water tank measurements for all proton energies. Upon applying a range calibration factor, the maximum deviation is 0.4 g/cm2. The MLFC range showed no dependence on the number of monitor units and the source-to-surface distance. Range measurements collected over multiple weeks exhibited stability. The total charge collected agrees closely with the theoretical charge from the treatment planning system beam model for low- and mid-range energies. We have calibrated and commissioned the use of the MLFC to easily verify range and total charge of proton beams. This tool will improve the workflow efficiency of the proton QA.

Measurement of Turbulent Kinetic Energy in Hypertrophic Cardiomyopathy Using Triple-velocity Encoding 4D Flow MR Imaging.

The turbulent kinetic energy (TKE) estimation based on 4D flow MRI has been currently developed and can be used to estimate the pressure gradient. The objective of this study was to validate the clinical value of 4D flow-based TKE measurement in patients with hypertrophic cardiomyopathy (HCM). From April 2018 to March 2019, we recruited 28 patients with HCM. Based on echocardiography, they were divided into obstructed HCM (HOCM) and non-obstructed HCM (HNCM). Triple-velocity encoding 4D flow MRI was performed. The volume-of-interest from the left ventricle to the aortic arch was drawn semi-automatically. We defined peak turbulent kinetic energy (TKEpeak) as the highest TKE phase in all cardiac phases. TKEpeak was significantly higher in HOCM than in HNCM (14.83 ± 3.91 vs. 7.11 ± 3.60 mJ, P < 0.001). TKEpeak was significantly higher in patients with systolic anterior movement (SAM) than in those without SAM (15.60 ± 3.96 vs. 7.44 ± 3.29 mJ, P < 0.001). Left ventricular (LV) mass increased proportionally with TKEpeak (P = 0.012, r = 0.466). When only the asymptomatic patients were extracted, a stronger correlation was observed (P = 0.001, r = 0.842). TKE measurement based on 4D flow MRI can detect the flow alteration induced by systolic flow jet and LV outflow tract geometry, such as SAM in patients with HOCM. The elevated TKE is correlated with increasing LV mass. This indicates that increasing cardiac load, by pressure loss due to turbulence, induces progression of LV hypertrophy, which leads to a worse prognosis.

Research advances in antimatter

The asymmetric origin of matter and antimatter in the universe is an important unsolved mystery in science today. In this paper, we briefly review the history of antimatter research and the recent international hotspots of related research. This paper focuses on the advances in antimatter research made in recent years at the large-scale international RHIC-STAR experiment at the Relativistic Heavy Ion Collider, including the discovery of the first antimatter hypernucleus (anti-hypertriton), antimatter helium 4 and antihyperhydrogen 4, the first measurements of antiproton interactions, and the precise measurements of the mass and binding energy of the hypertriton and anti-hypertriton. The antimatter hypertriton nucleus, composed of an antiproton, an antineutron, and an anti-Λ hyperon, is the first anti-hypernucleu to be discovered, extending the three-dimensional nuclide map from the anti-strange quark degree of freedom. Antimatter Helium 4 is the heaviest stable antimatter nucleus yet discovered. Anti-hyperhydrogen 4, just discovered in 2024, is composed of an antiproton, two antineutrons, and an anti-Λ hyperon, and is the heaviest antimatter hypernucleus to date. Equivalence to the proton-proton interaction was established by measurements of the antiproton-antiproton interaction. At the same time, precise measurements of the mass of hypertriton and anti-hypertriton nuclei confirmed the equivalence of matter and antimatter. And these also fully demonstrate that the CPT symmetry is also valid for antimatter nuclei. Measurements of the binding energy of the hypertriton nucleus indicate that the interaction between Λ and the nucleus of the hypertriton (the deuterium nucleus) is strong, which differs from the earlier common belief that the hypertriton nucleus is a weakly bound system. Furthermore, we discuss different physical mechanisms for the production of (anti) light nuclei, mainly including thermal, coalescence and relativistic kinetic models. Finally, we also present recent results from antihydrogen atom experiments at CERN, antimatter space probes, etc., and discuss the implications of these advances for understanding the structure of matter. Overall, the existing studies of antimatter nuclei and atoms have not yet provided clear evidence for the asymmetric origin of matter and antimatter in the universe, which can help further improve the accuracy of various measurements in antimatter research. Of course, other efforts in this direction in nuclear and particle physics are well expected.

Optimal Energy Storage System Selection: A Decision Support Framework

This study enhances the domain of optimum energy storage system selection by offering a complete decision support framework that incorporates technical, economic, and environmental factors. The technical investigation examines energy and power density measurements, which demonstrate the exceptional volumetric energy storage capacities of lithium-ion batteries at 250 Wh/L. This highlights their appropriateness for applications that prioritize compactness. Lead-acid batteries are a cost-effective option that have a lower energy density of 80 Wh/L. This makes them particularly advantageous in situations where volume limitations are not as important. Flow batteries and supercapacitors are positioned in the middle, with flow batteries offering a well-balanced profile of energy and power density, while supercapacitors excel in applications that need fast charging and discharging. An in-depth evaluation of the startup costs and ongoing expenditures is conducted to thoroughly assess the economic feasibility of adopting an energy storage system. Although lithium-ion batteries have a higher upfront cost of $100,000, they demonstrate a well-balanced economic profile by offering a significant 66% decrease in operating expenditures compared to lead-acid batteries. Lead-acid batteries, which have an initial price tag of $60,000, demonstrate cost-effectiveness but result in higher ongoing costs. Flow batteries and supercapacitors are positioned as premium alternatives, with respective beginning prices of $150,000 and $200,000. Environmental sustainability is a fundamental factor that is assessed via life cycle analysis. Lithiumion batteries, while very efficient, give rise to problems over resource depletion and environmental damage linked to mining activities. Lead-acid batteries, due to their recyclability, provide a more ecologically sound alternative. Flow batteries, which use readily available and environmentally safe components, are very compatible with objectives aimed at promoting sustainability. Supercapacitors, which often use ecologically friendly materials, have potential in reducing negative environmental impacts. MultiCriteria Decision Analysis (MCDA) is used to integrate technical, economic, and environmental assessments. Lithium-ion batteries are considered the most favorable choice due to their exceptional technical performance and economic viability. Lead-acid batteries have a strong market position due to their cost-efficiency and ecofriendliness. Flow batteries and supercapacitors, while they have distinct benefits, are only suitable for certain applications. The stability of the framework is shown by sensitivity analysis, which identifies energy density and beginning costs as crucial factors. Engaging stakeholders helps confirm the framework’s usefulness, ensuring that it can be practically used and remains relevant in guiding well-informed choices in the ever-changing field of energy storage technologies. This study provides vital insights into the discussion on sustainable and efficient energy solutions, presenting a clear plan for decision-makers to navigate the intricacies of selecting energy storage systems.

Photovoltaics Efficiency on Automatic Fish Feeding Distributors Device Using Internet of Things

Renewable energy is crucial for facilitating the shift towards a more sustainable society. It plays a significant role in establishing a clean energy system, mitigating greenhouse gas emissions, and enhancing the well-being of both current and future generations. The study included field observation and data analysis approaches. The study utilized IoT-based automatic fish feed spreaders, photovoltaic units, batteries, SCC (solar charge controller), Android phones, thermometers, multimeter tester, LCDs, ultrasonic sensors, and a microcontroller circuit. This study aims to acquire power, electrical energy, and efficiency measurements from solar systems employed in an Internet of Things (IoT) enabled automatic fish feeder apparatus. The results show that the power consumption needed to operate the IoT-based automatic fish feeder gadget is 48.75 watts. The peak of solar irradiance was recorded at 12.00 WIT, averaging 900.27 W/m2. The lowest intensity was at 09.00 WIT, averaging 422.78 W/m2. Photovoltaics can produce electrical power at 22.75 watts per hour, leading to a daily electrical energy output of 159.25 Wh. The highest photovoltaics efficiency was 16.37% with 465.3 W/m2 of solar irradiance, 30.7°C of temperature and 2.144 m/s of wind speed. The temperature and wind speed has significantly affected on photovoltaics efficiency.

An assessment of fertilizer spraying drones based on hesitancy fuzzy similarity measures for sustainable green development

This research proposes a new similarity measure on hesitancy fuzzy graphs. The similarity measures are crucial concepts to explore the closeness between fuzzy graphs. The available imprecise and inconsistent data were more effectively handled by fuzzy similarity measures and intuitionistic fuzzy similarity measures. With time in decision-making theory, a complex frame of the background that occurs cannot be specified entirely by these fuzzy graphs but generalized fuzzy graphs like the hesitancy fuzzy graph can handle such a situation efficiently. The applicability of Hesitancy Fuzzy Graph (HFG) attracted the researchers to generalize ranking order based on the working procedures I, II of Xu’s approach and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) approach. For this purpose, we first define hesitancy fuzzy preference relations, Laplacian energy, and similarity measures in these HFG. The decision-making technique is then proposed in which a weighting technique is developed by building an optimal model based on the proposed Laplacian energy and similarity measure under a hesitancy fuzzy environment. This research studies the decision-making problem in which the preference information given by the experts takes the form of Hesitancy Fuzzy Preference Relations (HFPRs) and the information about experts’ weights are completely unknown. This research utilizes the hesitancy fuzzy weighted averaging operator to aggregate all individual HFPRs into a collective HFPR. Then, based on the degree of similarity between the individual HFPRs and the collective ones, we develop an approach to determine the experts’ weights. Moreover, based on HFPRs, in which the similarity measures between the collective preference relation and hesitancy fuzzy ideal solution are used to rank the given alternatives. We provide an illustrative numerical example to illustrate the mentioned approach and also we compare the aggregate results of the two techniques.

Dynamics of self-hybridized exciton–polaritons in 2D halide perovskites

Excitons, bound electron–hole pairs, in two-dimensional hybrid organic inorganic perovskites (2D HOIPs) are capable of forming hybrid light-matter states known as exciton-polaritons (E–Ps) when the excitonic medium is confined in an optical cavity. In the case of 2D HOIPs, they can self-hybridize into E–Ps at specific thicknesses of the HOIP crystals that form a resonant optical cavity with the excitons. However, the fundamental properties of these self-hybridized E–Ps in 2D HOIPs, including their role in ultrafast energy and/or charge transfer at interfaces, remain unclear. Here, we demonstrate that >0.5 µm thick 2D HOIP crystals on Au substrates are capable of supporting multiple-orders of self-hybridized E–P modes. These E–Ps have high Q factors (>100) and modulate the optical dispersion for the crystal to enhance sub-gap absorption and emission. Through varying excitation energy and ultrafast measurements, we also confirm energy transfer from higher energy E–Ps to lower energy E–Ps. Finally, we also demonstrate that E–Ps are capable of charge transport and transfer at interfaces. Our findings provide new insights into charge and energy transfer in E–Ps opening new opportunities towards their manipulation for polaritonic devices.

Assessment of energy gain in SPV Tree structure with bifacial PV modules in Rajasthan

With the rising use of renewable energy generation sources, there is a need for dependable and sustainable measuring techniques to monitor and measure the performance of the energy sources. Existing guidelines and standards for measurement of performance of PV modules are specified only for monofacial PV modules, in which the measurement of irradiance falling on the PV module is irrespective of the ground-clearance or mounting height up to a certain extent. With reference to techno-commercial aspects, the pitch in a ground-mounted power plant is set based on how optimum energy generation can be obtained with minimum land utilization. In case of bifacial PV modules, generation gain can be achieved by varying the ground-clearance/mounting height of the modules as the energy generation depends on the irradiance on both front as well as back side of the module. In this research study, the authors have compared field measurements of energy gained by varying the ground-clearance of bifacial PV modules by using bifacial PV modules in a novel structure of SPV Tree. The simulation and practical results show that the energy gain increases up to 3.5% in Marigold SPV Tree structure as the mounting height is 4 m, contrary to a conventional ground-mounted structure with mounting height 0.5 m from the ground.

Research on the Characteristics of Photovoltaic, Storage, Direct-Current and Flexibility System for Flue-Cured Tobacco Room in Chongqing

With the implementation of China’s “Carbon Peaking and Carbon Neutrality Goals” policy, the efficient utilization technology of green energy such as solar energy has been further promoted and popularized. However, research on PSDF (Photovoltaic, Storage, Direct-Current, Flexibility) buildings is still in the demonstration construction stage, and there is still limited research on its application in the heating system of flue-cured tobacco room. This paper discusses the photovoltaic energy scenarios in Chongqing area and reviews the progress of research on solar energy-assisted heating systems in flue-cured tobacco production. It analyses the transient changes in the thermal-humidity load of the flue-cured tobacco room. Based on the direct proportionality of thermal-humidity load and heating equipment power, it provides flexibility indicators for measuring the flexible power system of the flue-cured tobacco room. Furthermore, it proposes technical measures for energy saving and carbon reduction in flue-cured tobacco room, providing a technical route for the early realization of low-carbon flue-cured tobacco.

Elucidating gas-surface interactions relevant to atmospheric particle growth using combined temperature programmed desorption and temperature-dependent uptake.

Understanding growth mechanisms for particles in air is fundamental to developing a predictive capability for their impacts on human health, visibility, and climate. In the case of highly viscous semi-solid or solid particles, the likelihood of impinging gases being taken up to grow the particle will be influenced by the initial uptake coefficient and by the residence time of the adsorbed gas on the surface. Here, a new approach that combines Knudsen cell capabilities for gas uptake measurements with temperature programmed desorption (TPD) for binding energy measurements of gases is described. The application of this unique capability to the uptake of organic gases on silica demonstrates its utility and the combination of thermodynamic and kinetic data that can be obtained. Lower limits to the initial net uptake coefficients at 170 K are (3.0 ± 0.6) × 10-3, (4.9 ± 0.6) × 10-3 and (4.3 ± 0.8) × 10-3 for benzene, 1-chloropentane, and methanol, respectively, and are reported here for the first time. The uptake data demonstrated that the ideal gas lattice model was appropriate, which informed the analysis of the TPD data. From the thermal desorption measurements, desorption energies of 34.6 ± 2.5, 45.8 ± 5.5, and 40.0 ± 5.6 kJ mol-1 (errors are 1σ) are obtained for benzene, 1-chloropentane, and methanol, respectively, and show good agreement with previously reported measurements. A multiphase kinetics model was applied to quantify uptake, desorption, and diffusion through the particle multilayers and hence extract desorption kinetics. Implications for uptake of organics on silica surfaces in the atmosphere and the utility of this system for determining relationships between residence times of organic gases and particle surfaces of varying composition are discussed in the context of developing quantitative predictions for growth of aerosol particles in air.

On-Device Deep Learning: Survey on Techniques Improving Energy Efficiency of DNNs.

Providing high-quality predictions is no longer the sole goal for neural networks. As we live in an increasingly interconnected world, these models need to match the constraints of resource-limited devices powering the Internet of Things (IoT) and embedded systems. Moreover, in the era of climate change, reducing the carbon footprint of neural networks is a critical step for green artificial intelligence, which is no longer an aspiration but a major need. Enhancing the energy efficiency of neural networks, in both training and inference phases, became a predominant research topic in the field. Training optimization has grown in interest recently but remains challenging, as it involves changes in the learning procedure that can impact the prediction quality significantly. This article presents a study on the most popular techniques aiming to reduce the energy consumption of neural networks' training. We first propose a classification of the methods before discussing and comparing the different categories. In addition, we outline some energy measurement techniques. We discuss the limitations identified during our study as well as some interesting directions, such as neuromorphic and reservoir computing (RC).

Hybrid bio-nanoporous peptide loaded-polymer platforms with anticancer and antibacterial activities.

In this study, hybrid bio-nanoporous peptides loaded onto poly(N-isopropylacrylamide-co-butylacrylate) (pNIPAM-co-BA) coatings were designed and obtained via matrix-assisted pulsed laser evaporation (MAPLE) technique. The incorporation of cationic peptides magainin (MG) and melittin (Mel) and their combination was tailored to target synergistic anticancer and antibacterial activities with low toxicity on normal mammalian cells. Atomic force microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy as well as contact angle and surface energy measurements revealed the successful and functional incorporation of both the peptides within porous polymeric nanolayers as well as surface modifications (i.e. variation in the pore size diameter, surface roughness, and wettability) after Mel, MG or Mel-MG incorporation compared to pNIPAM-co-BA. In vitro testing revealed the impairment of biofilm formation on all the hybrid coatings while testing with S. aureus, E. coli and P. aeruginosa. Moreover, MG was shown to modulate the effect of Mel in the combined Mel-MG extract formulation released via pNIPAM-platforms, thus significantly reducing cancer cell proliferation through apoptosis/necrosis as revealed by flow cytometry analysis performed in vitro on HEK293T, A375, B16F1 and B16F10 cells. To the best of our knowledge, Mel-MG combination entrapped in the pNIPAM-co-BA copolymer has not yet been reported as a new promising candidate with anticancer and antibacterial properties for improved utility in the biomedical field. Mel-MG incorporation compared to pNIPAM-co-BA in in vitro testing revealed the impairment of biofilm formation in all the hybrid formulations.

Exceptionally dense and resilient critically jammed polydisperse disk packings.

Understanding the way disordered particle packings transition between jammed (rigid) and unjammed (fluid) states is of both great practical importance and strong fundamental interest. The values of critical packing fraction (and other state variables) at the jamming transition are protocol dependent. Here, we demonstrate that this variability can be systematically traced to structural measures of packing, as well as to energy measures inside the jammed regime. A novel generalized simultaneous particle swap algorithm constructs overjammed states of desired energy, which upon decompression lead to predictable critical packing fractions. Thus, for a given set of particle sizes, states with extraordinarily high critical packing fractions can be found efficiently, which sustain substantial shear strain and preserve their special structure over the entire jammed domain. The close relation revealed here between the energy landscape of overjammed soft-particle packings and the behavior near the jamming transition points towards new ways of understanding and constructing disordered materials with exceptional properties.

Photocatalytic activity of a 2D copper porphyrin metal-organic framework for visible light overall water splitting.

A 2D copper tetrakis(4-carboxyphenyl)porphyrin metal-organic framework has been prepared and used as a photocatalyst for overall water splitting, measuring under visible light irradiation (λ > 450 nm) under one sun power conditions a H2 production rate of 120 μmolH2 gcatalyst -1 h-1 that is among the highest ever reported. While the 2D Cu porphyrin MOF undergoes substantial degradation in 3 h upon UV irradiation (320-380 nm) in the presence of air, it appears to be photostable under the conditions of the overall water splitting and visible light exposure, exhibiting similar temporal profiles for H2 and O2 evolution. Photocurrent experiments and band energy measurements indicate that the photocatalytic efficiency derives from an efficient charge separation in the visible region (apparent electron charge extraction efficiency at 540 nm of 0.1%) and adequate alignment of the redox potential of the conduction (-0.59 V vs. NHE) and valence (+1.48 V vs. NHE) bands for water splitting.