•High thermal conductivity phase change composite for thermal energy storage.•Hybrid HVAC/thermal energy storage with high-conductivity phase change composite.•Hybrid HVAC-TES for flexible resource ...to shave/shift on-peak power demand.•HVAC efficiency and optimized control strategies for smart grid applications.•HVAC-thermal storage system level modeling and simulation study using Aspen Plus®.
This paper evaluates the use of a phase change composite (PCC) material consisting of paraffin wax (n-Tetradecane) and expanded graphite as a potential storage medium for cold thermal energy storage (TES) systems to support air conditioning applications. The PCC-TES system is proposed to be integrated with the vapor compression refrigeration cycle of an air conditioning (AC) system. The use of this PCC material is novel because of its unique material and thermal characteristics as compared to ice or chilled water that are predominantly used in commercial TES systems for air cooling applications. The work of this paper proposed and tested a hypothesis, which suggests that integrating a conventional AC with a PCC-TES would result in significant benefits concerning compressor size, compressor efficiency, electricity consumed and CO2 emissions. The proposed integration would also contribute to reduce electricity demand during peak hours and reduce necessity to build more expensive power plants and distribution lines. To test the hypothesis, a simulation model in Aspen Plus® software was prepared. However, Aspen Plus® does not have a built-in library to predict PCC’s melting and solidification behaviors. Therefore, an analytical heat transfer model was written as a system of equations in Fortran code into Aspen Plus® calculation block to simulate the phase change behavior and associated characteristics. The overall simulation model, which was designed specifically for this research work, consists of two main parts that communicate with each other. The first part simulates the AC’s refrigeration loop using the built-in Aspen Plus® components and the second part implements the PCC heat transfer model written within the calculation block of Aspen Plus®. The simulation model was validated by crosschecking the calculated results with actual experimental data from an actual 4 kWh PCC-TES benchtop thermal storage system. Very good agreement was observed between the simulations and laboratory data. Simulated performance of the proposed integration between the AC and the PCC-TES indicated the potential to (1) downsize the compressor by 50%, (2) lower electrical consumption by the compressor by 30%, (3) lower CO2 emissions by 30%, and (4) double the compressor efficiency during off and mid peak hours. The present work is a conceptual design and optimization study and does not account for integration inefficiencies, energy losses, real-world operation complexity, and added capital cost of TES integration with AC systems.
Nigella sativa(N.sativa)(Family Ranunculaceae)is a widely used medicinal plant throughout the world.It is very popular in various traditional systems of medicine like Unani and Tibb,Ayurveda and ...Siddha.Seeds and oil have a long history of folklore usage in various systems of medicines and food.The seeds of N.saliva have been widely used in the treatment of different diseases and ailments.In Islamic literature,it is considered as one of the greatest forms of healing medicine.It has been recommended for using on regular basis in Tibb-e-Nabwi(Prophetic Medicine).It has been widely used as antihypertensive,liver tonics,diuretics,digestive,anti-diarrheal,appetite stimulant,analgesics,anti-bacterial and in skin disorders.Extensive studies on N.sativa have been carried out by various researchers and a wide spectrum of its pharmacological actions have been explored which may include antidiabetic,anticancer,immunomodulator,analgesic,antimicrobial,anti-inflammatory,spasmolytic,bronchodilator,hepato-protective,renal protective,gaslro-prolective,antioxidant properties,etc.Due to its miraculous power of healing,N.sativa has got the place among the top ranked evidence based herbal medicines.This is also revealed that most of the therapeutic,properties of this plant are due to the presence of thymoquinone which is major bioactive component of the essential oil.The present review is an effort to provide a detailed survey of the literature on scientific researches of pharmacognostical characteristics,chemical composition and pharmacological activities of the seeds of this plant.
Spiking neural networks (SNNs) are more energy- and resource-efficient than artificial neural networks (ANNs). However, supervised SNN learning is a challenging task due to non-differentiability of ...spikes and computation of complex terms. Moreover, the design of SNN learning engines is not an easy task due to limited hardware resources and tight energy constraints. In this article, a novel hardware-efficient SNN back-propagation scheme that offers fast convergence is proposed. The learning scheme does not require any complex operation such as error normalization and weight-threshold balancing, and can achieve an accuracy of around 97.5% on MNIST dataset using only 158,800 synapses. The multiplier-less inference engine trained using the proposed hard sigmoid SNN training (HaSiST) scheme can operate at a frequency of 135 MHz and consumes only 1.03 slice registers per synapse, 2.8 slice look-up tables, and can infer about 0.03Formula: see text features in a second, equivalent to 9.44 giga synaptic operations per second (GSOPS). The article also presents a high-speed, cost-efficient SNN training engine that consumes only 2.63 slice registers per synapse, 37.84 slice look-up tables per synapse, and can operate at a maximum computational frequency of around 50 MHz on a Virtex 6 FPGA.
The growing energy demand speed up the designing of competent photovoltaic materials. Herein, five zinc phthalocyanine-based donor materials
T1-T5
are designed by substituting various groups ...(isopropoxy, cyano, fluoro, methoxycarbonyl, and dicyanomethyl) around zinc phthalocyanine. B3LYP/6-31G (d,p) level density functional theory (DFT) was used to investigate the optoelectronic properties of five zinc phthalocyanine-based dyes
T1-T5
for dye-sensitized solar cells. The designed molecule
T1
shows maximum absorption wavelength (
λ
max
) in the absorption spectrum at 708.89 and 751.88 nm both in gaseous state and in
THF
(tetrahydrofuran) solvent. The
E
g
value of
T1
(1.86 eV) is less than reference
R
, indicating a greater charge transfer rate for
T1
among the molecules. The values of open-circuit voltages achieved with acceptor polymer PC
71
BM are higher than
R
except for
T1
and are 0.69 V, 1.95 V, 1.20 V, 1.44 V, and 1.84 V for
T1
,
T2
,
T3
,
T4
, and
T5
, respectively. The lower the reorganization energy, the higher the charge transfer for
T1
due to its lower hole mobility (0.06297 eV) than
R
. Thus, the designed
T1-T5
molecules are expected to exhibit superior performance in dye-sensitized solar cells.
We used a quantum chemical approach to investigate the optoelectronic properties of dyes
T1-T5
for dye-sensitized solar cells using DFT and TD-DFT computation. The newly designed molecules exhibited outstanding photovoltaic and optoelectronic properties.
Although antimicrobial resistance before the Covid-19 pandemic is a top priority for global public health, research is already ongoing on novel organic compounds with antimicrobial and antiviral ...properties in changing medical environments in connection with Covid 19. Thanks to the Biginelli reaction, which allows the synthesis of pyrimidine compounds, blockers of calcium channels, antibodies, antiviral, antimicrobial, anti-inflammatory, or antioxidant therapeutic compounds were investigated. In this paper, we aim to present Biginelli's synthesis, its therapeutic properties, and the structural–functional relationship in the test compounds that allows the synthesis of antimicrobial compounds. Both the DFT and TD-DFT computations of spectral data, molecular orbitals (HOMO, LUMO) analysis, and electrostatic potential (MEP) surfaces are carried out as an add-on to synthetic research. Hirshfeld surface analysis was also used to segregate the different intermolecular hydrogen bonds involved in the molecular packing strength. Natural Bond Orbital (NBO) investigation endorses the existence of intermolecular interactions mediated by lone pair, bonding, and anti-bonding orbitals. The dipole moment, linear polarizability, and first hyperpolarizabilities have been explored as molecular parameters. All findings based on DFT exhibit the best consistency with experimental findings, implying that synthesized molecules are highly stable. To better understand the binding mechanism of the SARS-CoV-2 Mpro, we performed molecular docking, molecular dynamics (MD) simulations, and binding free energy calculations.
Latent heat storage is one of the most efficient ways of storing thermal energy. Unlike the sensible heat storage method, the latent heat storage method provides much higher storage density, with a ...smaller temperature difference between storing and releasing heat. This paper reviews previous work on latent heat storage and provides an insight to recent efforts to develop new classes of phase change materials (PCMs) for use in energy storage. Three aspects have been the focus of this review: PCM materials, encapsulation and applications. There are large numbers of phase change materials that melt and solidify at a wide range of temperatures, making them attractive in a number of applications. Paraffin waxes are cheap and have moderate thermal energy storage density but low thermal conductivity and, hence, require large surface area. Hydrated salts have larger energy storage density and higher thermal conductivity but experience supercooling and phase segregation, and hence, their application requires the use of some nucleating and thickening agents. The main advantages of PCM encapsulation are providing large heat transfer area, reduction of the PCMs reactivity towards the outside environment and controlling the changes in volume of the storage materials as phase change occurs. The different applications in which the phase change method of heat storage can be applied are also reviewed in this paper. The problems associated with the application of PCMs with regards to the material and the methods used to contain them are also discussed.
Providing security to the citizens is one of the most important and complex task for the governments around the world which they have to deal with. Street crimes and theft are the biggest threats for ...the citizens and their belonging. In order to provide security, there is an urgent need of a system that is capable of identifying the criminal in the crowded area. This paper proposes a facial recognition system using Local Binary Patterns Histogram Face recognizer mounted on drone technology. The facial recognition capability is a key feature for a drone to have in order to find or identify the person within the crowd. With the inception of drone technology in the proposed system, we can use it as a surveillance drone as well through which it can cover more area as compared to the stationary system. As soon as the system identifies the desired person, it tags him and transmits the image along with the co-ordinates of the location to the concerned authorities using mounted global positioning system. Proposed system is capable of identifying the person with the accuracy of approximately 89.1%.
Summary
To address the growing demand for competent photovoltaic materials, the electronic structure, and optoelectronic properties of eight molecules X1 (thieno3,2‐bthiophene), X2 (5,5′‐bithiazole), ...X3 (2,2′‐bithiophene), X4 (furan), X5 (1H‐pyrrole), X6 (furo3,2‐bfuran), X7 (5‐(1H‐imidazol‐5‐yl)oxazole), X8 (3H,3′H‐4,4′‐biimidazole) designed via π‐spacer modification were investigated by extensive density functional theory (DFT) based calculations. The calculated HOMO‐LUMO energy (Eg) values of these designed molecules are less than alkoxy‐substituted benzothiadiazole and a rhodamine end group reference (R, Eg = 2.55 eV), whereas X8 shows the lowest (Eg = 2.17 eV) suggesting a greater charge transfer rate upon blending with donor polymer PTB7‐Th. The values of open‐circuit voltages for designed molecules are 2.30, 2.52, 2.23, 2.52, 2.37, 2.19, 2.53, and 2.18 V for X1‐X8, respectively, where X3, X6, and X8 shown lower voltages than the reference R (2.30 V). Similarly, the 0.13 eV difference of reorganization energy value of X1 compared to reference R, demonstrates higher charge transfer by X1 due to its lower hole mobility. The findings suggest potentially superior performance of organic solar cells (OSCs) fabricated with the designed molecules (X1‐X8).
We used a quantum chemical approach to address the growing demand for competent photovoltaic materials, with excellent electronic structure, and optoelectronic properties, eight molecules X1‐X8 were designed via π‐spacer modification and investigated using DFT and TD‐DFT computation. The newly designed molecules exhibited outstanding photovoltaic and optoelectronic properties.
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•The report compares the adsorption of small gaseous molecules including, N2O, NO2, NO, H2S, SO2, and SO3 onto the Be12O12, Mg12O12 & Ca12O12 nanocages within the density functional ...theory framework.•Our thermodynamic analysis reveals that the gaseous molecules strongly bind with C12O12 nanocage with the maximum interaction energy of ∼ 124 kcal/mol for SO3@Ca12O12.•The general trend of adsorption of small gaseous molecules onto the selected nanocages is as follows Ca12O12 > Mg12O12 > Be12O12.•These gaseous molecules cause a significant effect on the electronic behaviour of nanocages.
The gas sensing applications of nanocages find intense attention in environmental monitoring. In this research, the adsorption of nitrogen and sulfur-containing gaseous molecules i.e., N2O, NO2, NO, H2S, SO2, and SO3 on inorganic oxide nanocages are analyzed through DFT simulations. The adsorption of gaseous molecules with Be12O12, Mg12O12, and Ca12O12 is illustrated through the adsorption energies, optimized geometries, and electronic properties like HOMO-LUMO energies and NBO analysis. Our theoretical analysis indicates that the molecules strongly bind with the Ca12O12 nanocage. The adsorption energies of N2O@Ca12O12, NO2@Ca12O12, NO@Ca12O12, H2S@Ca12O12, SO2@Ca12O12 and SO3@Ca12O12 are −11.79, −46.53, −26.51, −50.26, −78.64 and −123.62 kcal/mol, respectively. Moreover, the HOMO-LUMO orbital analysis, density of state analysis (DOS), and natural bond orbital (NBO) analysis illustrate the significant impact of adsorption of these molecules on the electronic properties of respective nanocages, especially Ca12O12. Finally, it can be concluded that the Ca12O12 nanocage shows promising sensitivity towards the gaseous molecules which is followed by Mg12O12 and Be12O12.
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