Concurrent Generation Research Articles

Method of Priority Order for Simultaneous Solar-Derived Power Usage at a Solar-Powered House and Neighborhood

An advantage of solar-powered houses is the concurrent generation and consumption of power. However, the simultaneous power consumption of a solar-powered house tends to be lower than its actual load consumption. We aim to design a multi-agent system for exchanging the power value information within a solar-powered house and neighborhood in order to maximize simultaneous solar-derived power usage. This study purposes a priority order to determine the simultaneous solar-derived power usage procedure. Using the measurement data of a next-generation solar-powered house on a sunny day, we evaluate the estimation result of the domestic power balance and analyze the time series of each of the power variabilities. From the result, the three types of power usage are classified, and the four phases of the power capacity allocation are defined. We clarify the specific calculation procedure and indicate the availability of simultaneous solar-derived power usage by finding the optimum combination of the power capacity and the usage volume per hour. Finally, we estimate that the total value of available simultaneous solar-derived power usage is approximately 80% of the capacity in the solar-powered house and four hypothetical neighborhood houses, contributing to a drastic reduction in surplus power.

Radical‐Cation Cascade to Aryltetralin Cyclic Ether Lignans Under Visible‐Light Photoredox Catalysis

AbstractThe development of concise, sustainable, and cost‐effective synthesis of aryltetralin lignans, bearing either a fused lactone or cyclic ether, is of significant medicinal importance. Reported is that in the presence of Fukuzumi's acridinium salt under blue LED irradiation, functionalized dicinnamyl ether derivatives are converted into aryltetralin cyclic ether lignans with concurrent generation of three stereocenters in good to high yields with up to 20:1 diastereoselectivity. Oxidation of an alkene to the radical cation is key to the success of this formal Diels–Alder reaction of electronically mismatched diene and dienophile. Applying this methodology, six natural products, aglacin B, aglacin C, sulabiroin A, sulabiroin B, gaultherin C, and isoshonanin, are synthesized in only two to three steps from readily available biomass‐derived monolignols. A revised structure is proposed for gaultherin C.

Radical‐Cation Cascade to Aryltetralin Cyclic Ether Lignans Under Visible‐Light Photoredox Catalysis

The development of concise, sustainable, and cost-effective synthesis of aryltetralin lignans, bearing either a fused lactone or cyclic ether, is of significant medicinal importance. Reported is that in the presence of Fukuzumi's acridinium salt under blue LED irradiation, functionalized dicinnamyl ether derivatives are converted into aryltetralin cyclic ether lignans with concurrent generation of three stereocenters in good to high yields with up to 20:1 diastereoselectivity. Oxidation of an alkene to the radical cation is key to the success of this formal Diels-Alder reaction of electronically mismatched diene and dienophile. Applying this methodology, six natural products, aglacin B, aglacin C, sulabiroin A, sulabiroin B, gaultherin C, and isoshonanin, are synthesized in only two to three steps from readily available biomass-derived monolignols. A revised structure is proposed for gaultherin C.

A Preliminary Conceptual Model of the Assessment Design Process utilized by MCAST Science-Subject Lecturers

The main purpose of this research study was the construction of a preliminary theoretical model that explores the interrelation of the knowledge, skills and beliefs that shape MCAST (Malta College of Arts, Science & Technology) lecturers’ approaches to assessment design. Educational research across many countries has demonstrated that assessment has a greater bearing on what students learn than teaching itself. Despite the large body of literature focusing on educational assessment, studies that attempt to explain the assessment design process through theoretical modelling are scanty. This research was intended to address that gap. A constructivist-driven grounded theory methodology was applied using multiple sources of data. Data was generated through recorded, semi-structured interviews with four MCAST science lecturers, selected purposefully from different academic backgrounds and with varying degrees of teaching experience. In addition, further data was collected from field observations and in-depth document analysis of assessment briefs. Through a process of concurrent data generation and analysis, a comprehensive analytical framework, grounded in the data, emerged. The assessment design process model resulted from the ‘actions/interactions and emotions’ domain of the analytical framework. It was subject to the ‘contextual conditions’ domain, which included the knowledge (assessment literacy), skills and beliefs of the participants. The latter directly influenced the ‘consequences/outcomes’ domain, the constructs of which were mostly derived from the analysis of assessment briefs which represented the end-product of the assessment design process itself. The findings of this study revealed that most of the participants’ approaches to assessment were rooted in the outmoded 20th-century dominant paradigm. These results concur with the findings of many other assessment-related research studies across the world that state that this paradigm still dominates the discourse in higher education assessment, despite the body of evidence pointing to more effective practices rooted in the espoused constructivist educational theories. These findings could thus be useful to formulate assessment improvement strategies which address the contextual conditions over which the organization has a degree of influence, and which in turn will have a cascade effect on the individuals’ assessment practices. The ideal outcome of such strategies would be the promotion of constructively aligned assessment practices and the prevalent adoption of ‘connected’ mental models amongst academic staff.

Uncovering Atomic‐Scale Stability and Reactivity in Engineered Zinc Oxide Electrocatalysts for Controllable Syngas Production

AbstractIn this study, scalable, flame spray synthesis is utilized to develop defective ZnO nanomaterials for the concurrent generation of H2 and CO during electrochemical CO2 reduction reactions (CO2RR). The designed ZnO achieves an H2/CO ratio of ≈1 with a large current density (j) of 40 mA cm−2 during long‐term continuous reaction at a cell voltage of 2.6 V. Through in situ atomic pair distribution function analysis, the remarkable stability of these ZnO structures is explored, addressing the knowledge gap in understanding the dynamics of oxide catalysts during CO2RR. Through optimization of synthesis conditions, ZnO facets are modulated which are shown to affect reaction selectivity, in agreement with theoretical calculations. These findings and insights on synthetic manipulation of active sites in defective metal‐oxides can be used as guidelines to develop active catalysts for syngas production for renewable power‐to‐X to generate a range of fuels and chemicals.

Wavelength‐Dependent Singlet Oxygen Generation in Luminescent Lanthanide Complexes with a Pyridine‐Bis(Carboxamide)‐Terthiophene Sensitizer

Lanthanide ion (LnIII ) complexes, [Ln(3Tcbx)2 ]3+ (LnIII =YbIII , NdIII , ErIII ) are isolated with a new pyridine-bis(carboxamide)-based ligand with a 2,2':5',2''-terthiophene pendant (3TCbx), and their resulting photophysical properties are explored. Upon excitation of the complexes at 490 nm, only LnIII emission is observed with efficiencies of 0.29 % at 976 nm for LnIII =YbIII and 0.16 % at 1053 nm for LnIII =NdIII . ErIII emission is observed but weak. Upon excitation at 400 nm, concurrent 1 O2 formation is seen, with efficiencies of 11 % for the YbIII and NdIII complexes and 13 % for the ErIII complex. Owing to the concurrent generation of 1 O2 , as expected, the efficiency of metal-centered emission decreases to 0.02 % for YbIII and 0.05 % for NdIII . The ability to control 1 O2 generation through the excitation wavelength indicates that the incorporation of 2,2':5',2''-terthiophene results in access to multiple sensitization pathways. These energy pathways are unraveled through transient absorption spectroscopy.

Agricultural waste-derived moisture-absorber for all-weather atmospheric water collection and electricity generation

Abstract Harvesting water and energy from ambient environment promises to relieve the worldwide fresh-water scarcity and energy shortage. The fabrication of well-designed materials for atmospheric water harvesting (AWH) requires highly-technical skills, hampering practical applications in isolated regions or after natural disasters. Herein, we report an efficient moisture absorber from waste corn stalk for AWH and for concurrent electricity generation. The sample can adsorb water at capacities of 0.46–1.84 kg kg−1 under relative humidity of 20%–80%. Moreover, with surface modification using commercial carbon ink, a corn stalk slice (3 cm × 1 cm × 0.2 cm) can output a stable open-circuit voltage of ~0.6 V in the air. Density functional theory calculations reveal that the oxygen groups in the carbon ink contribute to the power generation in the corn stalk. When connected in series, corn stalk slices can directly power an electronic calculator. This study contributes to the development of practical strategies to address issues in the water-waste-energy nexus.

Potentiality of petrochemical wastewater as substrate in microbial fuel cell

The petrochemical wastewater (PCW) from acrylic acid plant possesses very high chemical oxygen demand (COD) due to presence of acrylic acid along with other organic acids. The treatment of PCW by conventional methods is energy intensive. The treatment of PCW with concurrent power generation by employing microbial fuel cell (MFC) could be a potential alternative solving the problem of energy and environment. The goal of the present paper is to evaluate the viability of treating the wastewater using anaerobic sludge as biocatalyst in a dual- chamber MFC for simultaneous power generation and wastewater treatment. This study demonstrates that anaerobic sludge (AS) could work as a biocatalyst producing maximum power density of 0.75 W/m3at current density and open circuit voltage (OCV) of 412 mA/m2 and 0.45 V respectively using PCW with an initial COD of 45,000 mg/L. The COD removal efficiency and the columbic efficiency (CE) were found 40% and 13.11%, respectively. The mechanism of electron transfer in the anode was analyzed by cyclic voltammetry (CV) and the resistances across the electrode/biofilm/solution interface were investigated by employing impedance spectroscopy (EIS). The current work proves the capability of the MFC for the treatment of acrylic acid plant PCW using anaerobic sludge (AS) as biocatalyst.

A N260 Band 64 Channel Millimeter Wave Full-Digital Multi-Beam Array for 5G Massive MIMO Applications

In this paper, a 37-42.5GHz (N260 Band) 64 channel full-digital multi-beam array for 5G massive multiple input multiple output (MIMO) applications is developed. The multi-beam array is built on a time division duplexing (TDD) architecture in which the transmitter and receivers are independent and working separately to enable more flexible channel configuration and hardware distribution. The 64 antenna elements of the array are aligned in a way that 16 elements lie in the horizontal and 4 in the vertical direction to deliver higher beam resolution in the horizontal plane. By using cables of unequal lengths, the $16\times 4$ antenna elements are connected to a cluster of $8\times 8$ transmitters/receivers. The hardware design of the transmitters, receivers, antennas and other circuits is demonstrated, with excellent measured RF performance achieved. Furthermore, the calibration of the massive MIMO array is presented, and the influence of inequality of array feedlines on calibration accuracy in a wide bandwidth is analyzed and experimentally verified. Finally, experimental studies on single beam scanning, multiple concurrent beam generation and over-the-air (OTA) performance of the transmitting and receiving array have been done. Simulation and measurement results suggest that the array has an excellent beam-forming capability that supports beam steering and generation of multiple concurrent beams. The OTA test reveals that the array can provide high modulation and demodulation accuracy for communication.

Optimal Combined Heat and Power Economic Dispatch Using Stochastic Fractal Search Algorithm

Combined heat and power (CHP) generation is a valuable scheme for concurrent generation of electrical and thermal energies. The interdependency of power and heat productions in CHP units introduces complications and non-convexities in their modeling and optimization. This paper uses the stochastic fractal search (SFS) optimization technique to treat the highly non-linear CHP economic dispatch (CHPED) problem, where the objective is to minimize the total operation cost of both power and heat from generation units while fulfilling several operation interdependent limits and constraints. The CHPED problem has bounded feasible operation regions and many local minima. The SFS, which is a recent metaheuristic global optimization solver, outranks many current reputable solvers. Handling constraints of the CHPED is achieved by employing external penalty parameters, which penalize infeasible solution during the iterative process. To confirm the strength of this algorithm, it has been tested on two different test systems that are regularly used. The obtained outcomes are compared with former outcomes achieved by many different methods reported in literature of CHPED. The results of this work affirm that the SFS algorithm can achieve improved near-global solution and compare favorably with other commonly used global optimization techniques in terms of the quality of solution, handling of constraints and computation time.

Multiple strengthening mechanisms in high strength ultrafine-grained Al–Mg alloys

High strength has always been pursued in binary Al–Mg and 5xxx series Al alloys. However, these alloys usually provide medium strength due to lack of multiple strengthening methods. Here, this study reports on multiple strengthening effects existing in a binary ultrafine-grained (UFG) Al-7.5at.%Mg alloy prepared by mechanical alloying and hot extrusion. Different strengthening mechanisms, in particular, dispersoid strengthening and stacking fault strengthening, are analyzed and evaluated in terms of their respective contribution to the 511 MPa yield strength of the alloy. The strengthening analysis proves that the concurrent generation of nanoscale dispersoids and stacking faults (SFs) can be used as a new microstructural design in developing novel Al–Mg-based alloys with higher strength and enhanced ductility.

Electrochemical sequential reduction and oxidation facilitates the continual ambient temperature degradation of SF6 to nontoxic gaseous compounds

An efficient process for the degradation of the potent greenhouse gas, SF6, into non-toxic gaseous products at ambient temperature is still desirable. In this study, consistently generable homogeneous low/high-valent metal ions were used to degrade SF6 to non-toxic gaseous products at ambient temperature. Two homogenous electron mediators, [Ni(I)(CN)4]3− (Ni(I) low-valent) and AgSO4 or Ag(NO3)2 (Ag(II) high-valent), were generated concurrently using a membrane-divided electrolytic cell and quantified by measuring the ORP (oxidation/reduction potential) variations along with a potentiometric titration. The variation of electrogenerated Ni(I) from 6.3 mM to 4.1 mM and Ag(II) from 4.8 mM to 4.3 mM during the removal of SF6 evidenced their concurrent generation, and SF6 removal followed a mediated electrocatalytic reduction (MER) and mediated electrocatalytic oxidation (MEO) process. FTIR online gas analyzer confirmed that using the MER process only, approximately 92% of the SF6 in a gas mixture containing 5 ppm of SF6 at a 0.2 L min−1 flow rate had decomposed to OF2 (7 ppm), SOF2 (2 ppm), and SO2 (2.9 ppm). At the same time, the MER-treated gas passed into Ag(II) generated anolyte solution resulted in the complete removal of SF6, SOF2, OF2, and SO2 by the MEO process. Also, the absence of fluoride containing gases and SO2 gas in the exit gas from the MEO process and the presence of fluoride ions in the anolyte solution demonstrates the aqueous soluble products fluoride and sulfate ions formation. The possible consistent generation of homogenous electrocatalysts and their combined use in SF6 degradation at ambient temperatures is a practical technology that can be scaled up to a more practical level.

The morphological changes upon cryomilling of cellulose and concurrent generation of mechanoradicals

With mechanical input, chemical bonds in polymers can be broken. Recently, it was shown that reactive ends formed by homolytic cleavage, so-called mechanoradicals, can be used in driving further chemical reactions or in making new composite materials. Cellulose, the most abundant polymer on earth, can also be subjected to mechanical input via ball-milling to produce mechanoradicals. Despite many reports on morphological changes in cellulose upon milling, there is only a limited understanding on how these changes affect the mechanoradical production, i.e., in which domains of cellulose the bonds are broken to produce the mechanoradicals. Here we show, the effect of the initial morphology of cellulose (cotton or microcrystalline cellulose) and the mode of grinding (dry or solvent-assisted) on the amount of generated cellulose mechanoradicals. The morphological and the chemical changes taking place upon milling of cellulose are monitored by SEM, XRD, and ATR, and the number of mechanoradicals is determined by a first-time quantitative analysis of cellulose mechanoradicals using radical scavenger DPPH. Our findings can help in efficient mechanofunctionalization of cellulose and to make useful mechanochemical reactions of cellulose using mechanoradicals, which stand as a promising economic and environment-friendly alternative to the conventional solvent-assisted chemistry of cellulose.

Ambient-temperature catalytic degradation of aromatic compounds on iron oxide nanorods supported on carbon nanofiber sheet

Fe2O3 nanorods loaded on carbon nanofiber sheet (Fe2O3/CNF) was found to be active in degrading aromatic pollutants spontaneously under the dark and ambient conditions without using any chemical reagent or external energy to assist the degradation reaction. The removal of aromatic pollutants was not caused by adsorption but by oxidative degradation since the generation of degradation intermediates and products was observed. The Fe2O3/CNF exhibited selective degradation activities for aromatic-compounds. Degradation was induced by Fe2O3/CNF only, whereas neither iron oxide nor bare CNF alone exhibited any degradation activity. The degradation on the Fe2O3/CNF was enabled only in the presence of dissolved O2 of which reduction led to the generation of reactive oxygen species (ROS). It is proposed that electrons spontaneously transfer from aromatic-compound to O2 viaFe2O3/CNF with initiating the oxidative degradation and the concurrent ROS generation. The direct electron transfer from organic compound to Fe2O3/CNF, which lead to oxidative degradation.

Bio-electrochemical power generation in petrochemical wastewater fed microbial fuel cell

The petrochemical wastewater (PCW) from acrylic acid plants possesses a very high chemical oxygen demand (COD) due to the presence of acrylic acid along with other organic acids. The treatment of PCW by conventional aerobic and anaerobic methods is energy intensive. Therefore, the treatment of PCW with concurrent power generation by employing microbial fuel cell (MFC) could be a potential alternative to solve the energy and environmental issues. This study demonstrates the potentiality of PCW from acrylic acid plant with an initial COD of 45,000 mg L−1 generating maximum power density of 850 mW m−2 at a current density of 1500 mA m−2 using acclimatized anaerobic sludge (AS) as biocatalyst. The predominant microbes present in acclimatized AS were identified using Biolog GEN III analysis, which include the electrogenic genera namely Pseudomonas spp. and Bacillus spp. along with methanogenic archea Methanobacterium spp. The mechanism of electron transfer was elucidated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) which clearly demonstrated the natural metabolite-based electron transfer across the electrode/biofilm/solution interface. The abundance of the electron shuttle metabolites was increased with the microbial growth in the bulk solution as well as in the biofilm leading to a high power generation. The COD removal efficiency and the coulombic efficiency (CE) were found to be 40% and 21%, respectively after 11 days of operation using initial COD of 45,000 mg L−1. The low COD removal efficiency could drastically be increased to 82% when the initial COD of PCW was 5000 mg L−1 generating a power density of 150 mW m−2. The current work proves the feasibility of the MFC for the treatment of acrylic acid plant PCW using acclimatized anaerobic sludge (AS) as a biocatalyst.

Life cycle energy and environmental impacts of a solid oxide fuel cell micro-CHP system for residential application

Fuel cells are considered one of the key technologies to reach the ambitious European goal of a low carbon economy, by reducing CO2 emissions and limiting the production of other pollutants.The manuscript presents an assessment of the life cycle energy and environmental performances of a solid oxide fuel cell system for household applications using primary data from the manufacturing phase and experimental data for the start-up and operation phases.The Life Cycle Assessment methodology is applied, based on a functional unit of 1 MJ of exergy and includes the life cycle steps from the raw materials extraction to the maintenance.The results show a particular relevance of the operation stage on the impacts (about 98% of cumulative energy demand and more than 63% of about half of the examined environmental impacts), mainly due to the fuel supply and, focusing on climate change, to the CO2 emissions during the conversion of chemical energy into electricity. Manufacturing step is the main responsible of the remaining half of the impacts, with a contribution higher than 38%, mainly imputable to the stacks production. For almost half of the examined impact, a contribution of 20–30% is caused by the maintenance step, with a relevant contribution of the stacks and DC/DC booster substitutions.The analysis highlights that eco-design solutions of the assessed system can be traced in the improvement of the energy system efficiency and reduction of emissions during the operation, and in the increase of the durability of the system components, thus reducing the number of their substitutions. The results of a sensitivity analysis on the selection of the functional unit also clarified the importance of the recovery of the thermal energy generated by the fuel cells, in order to avoid concurrent energy generation from conventional sources.

Interface state degradation during AC positive bias temperature instability stress

The reliability of a bulk fin field-effect transistor (FinFET) with a high-k dielectric/metal-gate stack has been investigated by comparing the effects of DC and AC stresses. It is well known that the relaxation during the off-cycle of the AC stress decreases the Vth shift and enhances the device lifetime due to electron detrapping from the high-k dielectric. We found that the relaxation in the interface traps is significantly weaker than that of bulk traps during the unipolar and bipolar AC stresses. The weak recovery is attributed to the concurrent interface state generation during a positive-bias temperature instability (PBTI) stress. Eventually, the interface traps became a major source of the device drift (over 60%) at the high temperature of 400 K. This finding suggests that a new strategy is required to address the PBTI reliability focusing on the residual interface states as well as the bulk trapping, particularly at a high temperature.

Surfactant addition to enhance bioavailability of bilge water in single chamber microbial fuel cells (MFCs).

Effective remediation of bilge water, a shipboard oily liquid waste, is important for both commercial and military vessels due to the domestic and international regulations. In this study, bilge water was used as a substrate for exoelectrogenic bacteria and biodegradation of bilge water and concurrent electricity generation were investigated using Pseudomonas putida ATCC 49128 in single chamber microbial fuel cells (MFCs). To enhance bioavailability of the bilge water, two types of surfactants were added (100 ppm) into the oily wastewater containing 0.1% standard bilge mix (SBM) and their impacts on electricity production were evaluated under various conditions. Anionic surfactant (sodium dodecyl sulfate, SDS) addition increased soluble chemical oxygen demand (SCOD) by forming micelle, producing maximum power density of 225.3 ± 3.2 mW m-2. However, the MFC with nonionic surfactant (Triton X-100) produced only 2.3 ± 0.1 mW m-2 due to no enhancement on biodegradable SCOD. A high NaCl concentration (100-500 mM) adversely affected power production due to decrease in available SCOD caused by emulsion coalescence. This is a first study to use surfactants to enhance bioavailability of non-biodegradable oily wastewater in a single chamber MFC.

Transition Metal and Rare Earth Element Doped Zinc Oxide Nanowires for Optoelectronics

Even though intrinsic semiconductor nanowires have already extraordinary optical properties, doping with optically active impurities significantly expands the potpourri of optoelectronic applications, such as for nanowire lasers or single photon emitters. This feature article therefore supplies a snapshot of the most recent progress on the structural and optical properties of transition metal and rare earth element doped zinc oxide (ZnO) nanowires using ion beam doping. Here, ion implantation is advantageous, as concurrent defect generation and diffusion upon subsequent annealing allows the formation of defect complexes. This scenario is in many cases even inevitable for the optical activation of the intra‐shell luminescence of the implanted impurities, as density functional theory calculations demonstrate. Finally, this article also provides the optimum preparation conditions for intense optical activity and a review on the specific luminescence properties of various optical centers in ZnO nanowires.

Engineered Polymeric Micelles for Combinational Oxidation Anticancer Therapy through Concurrent HO-1 Inhibition and ROS Generation.

Cancer cells have a large amount of ROS (reactive oxygen species) because of disturbed ROS homeostasis. Cancer cells therefore undertake redox adaptation to drive proliferation in tumor environments and even survive during anticancer treatment by upregulating endogenous antioxidants. As one of antioxidant defense systems, heme oxygenase-1 (HO-1) acts as an essential role in tumor development by offering antioxidant bilirubin to protect cancer cells under stress conditions. It can be therefore reasoned that the combination of ROS generation and HO-1 inhibition would exert synergistic anticancer effects through the amplification of oxidative stress and provide a new opportunity for targeted anticancer therapy. To establish targeted anticancer therapy based on amplified oxidative stress, we developed molecularly engineered polymer, termed CZP, which incorporates ROS generating CA (cinnamaldehyde) and HO-1 inhibiting ZnPP (zinc protoporphyrin) in its backbone and could form stable micelles in aqueous solutions. CZP micelles not only elevated oxidative stress but also suppressed the expression of antioxidant HO-1, leading to apoptotic cell death. CZP micelles could also significantly suppress the tumor growth without body weight loss, tumor recurrence, and noticeable toxicity in organs. This study demonstrates that a combination of ROS generation and HO-1inhibition synergistically magnifies oxidative stress to kill cancer cells and oxidative stress amplifying CZP micelles may provide a promising strategy in anticancer treatment.