Artificial intelligence and machine learning applications in the project lifecycle of the construction industry: A comprehensive review.

The construction industry faces many challenges, including schedule and cost overruns, productivity constraints, and workforce shortages. Compared to other sectors, it lags in digitalization in every project phase. Artificial Intelligence (AI) and Machine Learning (ML) have emerged as transformative technologies revolutionizing the construction sector. However, a discernible gap persists in systematically categorizing the applications of these technologies throughout the various phases of the construction project life cycle. In response to this gap, this research aims to present a thorough assessment of the deployment of AI and ML across diverse phases in construction projects, with the ultimate goal of furnishing valuable insights for the effective integration of these intelligent systems within the construction sector. A thorough literature review was performed to identify AI and ML applications in the building sector. After scrutinizing the literature, the applications of AI and ML were presented based on a construction project life cycle. A critical review of existing literature on AI and ML applications in the building industry showed that AI and ML applications are more frequent in the planning and construction stages. Moreover, the opportunities for AI and ML applications in other stages were discussed based on the life cycle categorization and presented in this study. The practical contribution of the study lies in providing valuable insights for the effective integration of intelligent systems within the construction sector. Academically, the research contributes by conducting a thorough literature review, categorizing AI and ML applications based on the construction project life cycle, and identifying opportunities for their deployment in different stages.

Arene and functionalized arene based two dimensional organic-inorganic hybrid perovskites for photovoltaic applications.

Recently, two-dimensional organic-inorganic hybrid perovskites have attracted great attention for their outstanding performances in solar energy conversion devices. By using first principles calculations, we explored the structural, electronic and optical properties of recently synthesized (PEA)2 PbI4 and (PEA)2 SnI4 organic-inorganic hybrid perovskites to understand the photovoltaic performances of these systems. Our study reveals that both the perovskites are direct band gap semiconductors and possess desirable band gap for solar energy absorption. We have further extended our study to fluoro-, chloro-, and bromo-functionalized phenethylammonium (PEA) cations based [X(X = F, Cl, Br)PEA]2 A(A = Pb, Sn)I4 perovskite materials. The halogenated benzene moiety confers an ultrahydrophobic character and protects the perovskites from ambient moisture. The halogen functionalized perovskites remain direct band gap semiconductors and all the perovskites show very strong optical absorption (∼7 × 105 cm-1 ) across UV-visible region. We have further calculated the photo-conversion efficiency (PCE) of both arene and functionalized arene based perovskites. The halogen-functionalized PEA-based perovskites also exhibit high PCE as like pristine ones and finally achieve high PCE of up to 24.30%, making them competitive with other previously reported perovskite-based photovoltaic devices.

Common Defects Accelerate Charge Separation and Reduce Recombination in CNT/Molecule Composites: Atomistic Quantum Dynamics.

Carbon nanotubes (CNTs) are appealing candidates for solar and optoelectronic applications. Traditionally used as electron sinks, CNTs can also perform as electron donors, as exemplified by coupling with perylenediimide (PDI). To achieve high efficiencies, electron transfer (ET) should be fast, while subsequent charge recombination should be slow. Typically, defects are considered detrimental to material performance because they accelerate charge and energy losses. We demonstrate that, surprisingly, common CNT defects improve rather than deteriorate the performance. CNTs and other low dimensional materials accommodate moderate defects without creating deep traps. At the same time, charge redistribution caused by CNT defects creates an additional electrostatic potential that increases the CNT work function and lowers CNT energy levels relative to those of the acceptor species. Hence, the energy gap for the ET is decreased, while the gap for the charge recombination is increased. The effect is particularly important because charge acceptors tend to bind near defects due to enhanced chemical interactions. The time-domain simulation of the excited-state dynamics provides an atomistic picture of the observed phenomenon and characterizes in detail the electronic states, vibrational motions, inelastic and elastic electron-phonon interactions, and time scales of the charge separation and recombination processes. The findings should apply generally to low-dimensional materials, because they dissipate defect strain better than bulk semiconductors. Our calculations reveal that CNT performance is robust to common defects and that moderate defects are essential rather than detrimental for CNT application in energy, electronics, and related fields.

Half metallicity and ferromagnetism of vanadium nitride nanoribbons: a first-principles study.

Half metallic materials with intrinsic ferromagnetism are identified as the pillar of next generation spintronic devices. In search of new low-dimensional materials with these excellent properties, herein we systematically study the electronic and magnetic properties of edge dependent (armchair (ac) and zigzag (zz)) vanadium nitride nanoribbons (VNNRs) using density functional theory (DFT) based calculations. Both the ac and zz VNNRs show robust ferromagnetism and extensive half-metallicity with large band gaps (3.9-4.3 eV for ac and 2.5-3.0 eV for zz VNNRs) for the down spin channel. Interestingly, even with the application of uniaxial strain (both tensile and compressive) along the axis of the ribbons, VNNRs retain their extensive half metallicity with a large spin band gap and robust ferromagnetic behavior. Spin dependent electronic transport reveals the 100% spin filtering efficiency of nanoribbons, in both the free state and under applied strain, which support the robust half metallicity of VNNRs. Our study of VNNRs on a MoS2 substrate also shows half metallicity along with high stability, indicating the usage of MoS2 as a substrate for the synthesis of VNNRs. All these results guide the potential application of VNNRs in spintronic devices.

Structural rigidity accelerates quantum decoherence and extends carrier lifetime in porphyrin nanoballs: a time domain atomistic simulation.

Nonradiative electron-hole (e-h) recombination is the primary source of energy loss in photovoltaic cells and inevitably, it competes with the charge transfer process, leading to poor device performance. Therefore, much attention has to be paid for delaying such processes; increasing the excitonic lifetime may be a solution for this. Using the real-time, density functional tight-binding theory (DFTB) combined with nonadiabatic molecular dynamics (NAMD) simulations, we demonstrate the exciton relaxation phenomena of different metal-centered porphyrin nanoballs, which are supposed to be very important for the light-harvesting process. It has been revealed that the carrier recombination rate gradually decreases with the increase in the molecular stiffness by introducing metal-coordinating templating agents into the nanoball. Our simulation demonstrates that the lower atomic fluctuations lead to poorer electron-phonon nonadiabatic coupling in association with weak phonon modes and these as a whole are responsible for shorter quantum coherence and hence delayed recombination events. Our analysis is in good agreement with the recent experimental observation. By replacing the Zn metal center with a heavier Cd atom, a similar trend is observed; however, the rate slows down abruptly. The present simulation study provides the fundamental mechanism in detail behind the undesired energy loss during exciton recombination and suggests a rational design of impressive nanosystems for future device fabrication.

Periodically-ordered one and two dimensional CdTe QD superstructures: a path forward in photovoltaics.

By using the state-of-the-art theoretical method, we herein explore the potentiality of covalently linked periodically-ordered 1D chain, 2D hexagonal and square ordered superstructures of CdTe QDs in photovoltaics. One of the major factors that controls the photovoltaic efficiency is the electron-hole recombination which in turn depends on the spatial separation of these charge carriers. Our theoretical findings show that the HOMO and LUMO states are localized at two different ends of the assembled superstructures. This result indicates large spatial separation of photoexcited charge carriers which prolongs the carrier lifetime and thus reduces the chance of electron-hole recombination. We have also attached an acceptor fullerene molecule with the CdTe QD superstructure and studied the electronic structure of the composite system. The photoexcited electrons of the assembled QDs potentially transfer to the low energy lying conduction band of fullerene and show a large spatial charge separation. The assembled QD-fullerene composites exhibit a high photoconversion efficiency of 19.3%, opening up new possibilities for designing efficient solar energy harvesting devices based on assembled QDs.

Engineering the magnetic properties of PtSe2 monolayer through transition metal doping.

Using first-principles calculations, we have studied the energetic feasibility and magnetic properties of transition metal (TM) doped PtSe2 monolayers. Our study shows that TM doped PtSe2 layers with 6.25% doping exhibit versatile spintronic behaviour depending on the nature of the dopant TM atoms. Groups IVB and VIII10 TM doped PtSe2 layers are non magnetic semiconductors, while groups IIIB, VB, VIII8, VIII9, IB TM doped PtSe2 layers are half-metals and finally, groups VIB, VIIB and IIB TM doped PtSe2 layers are spin polarized semiconductors. The presence of half-metallic and magnetic semiconducting characteristics suggest that TM doped PtSe2 layers can be considered as a new kind of dilute magnetic semiconductor and thus have the promise to be used in spintronics. By studying the magnetic interactions between two TM dopants in PtSe2 monolayers for dopant concentration of 12.5% and dopant distance of 12.85 [Formula: see text], we have found that in particular, Fe and Ru doped PtSe2 systems are ferromagnetic half-metal having above-room-temperature Curie point of 422 and 379.9 K, respectively. By varying the dopant distance and concentration we have shown that the magnetic interaction is strongly dependent on dopant distance and concentration. Interestingly, the Curie temperature of TM doped PtSe2 layers is affected by the correlation effects on the TM d states and also spin-orbit coupling. We have also studied the magnetic properties of defect complex composed of one TM dopant and one Pt vacancy (TMPt + VPt) which shows novel magnetism.

Total syntheses of (+/-)-platencin and (-)-platencin.

The secondary metabolites platensimycin and platencin, isolated from the bacterial strain Streptomyces platensis, represent a novel class of natural products exhibiting unique and potent antibacterial activity. Platencin, though structurally similar to platensimycin, has been found to operate through a slightly different mechanism of action involving the dual inhibition of lipid elongation enzymes FabF and FabH. Both natural products exhibit strong, broad-spectrum, gram-positive antibacterial activity to key antibiotic resistant strains, including methicillin-resistant Staphylococcus aureus, vancomycin-intermediate S. aureus, and vancomycin-resistant Enterococcus faecium. Described herein are our synthetic efforts toward platencin, culminating in both racemic and asymmetric preparation of the natural product. The syntheses demonstrate the power of the cobalt-catalyzed asymmetric Diels-Alder reaction and the one-pot reductive rearrangement of [3.2.1] bicyclic ketones to [2.2.2] bicyclic olefins.

Design, synthesis and DNA-cleaving efficiency of photoswitchable dimeric azobenzene-based C2-symmetric enediynes.

Designed azobenzene-based enediyne-amino acid C(2)-symmetric hybrids have been synthesized and the role of amino acid linker in stabilizing the Z form has been demonstrated; DNA-binding and cleavage studies have established higher reactivity of the Z-isomers.

Benzofused N-substituted cyclic enediynes: activation and DNA-cleavage potential.

The effect of electron withdrawal on the reactivity of N-substituted cyclic enediynes has been studied. These were synthesized via an intramolecular Mitsunobu reaction. The electron withdrawing effect of the nitro groups or the positive charge on the free ammonium salts was found to lower the cyclization temperature for Bergman cyclization. The ammonium salts cleave ds-DNA at nanomolar concentrations.

Synthesis and reactivity of azobenzene-based bispropargyl sulfones: interesting comparison between cyclic and acyclic systems.

Azobenzene-based bispropargyl bissulfone 3 containing stable E-azo moiety has been synthesized. Upon irradiation with long wavelength UV it isomerized to the Z-form 4, which can be thermally reisomerized to the E-isomer. Reactivity towards isomerization to the allenic system as well as DNA-cleaving efficiency under basic conditions was found to be significantly lower as compared to the previously synthesized cyclic sulfones 1 and 2. This lowering of reactivity can be explained in terms of low conversion to the allenic form and hence the lower extent of alkylation of DNA-bases, the only possible DNA-cleavage pathway for 3 and 4.

Photoisomerization as a modulator of the DNA-cleaving efficiency of novel azo bispropargyl sulfones.

Novel azobenzene based bispropargyl sulfones have been prepared in the thermally stable E-form: irradiation with a high-pressure Hg lamp converted them to the Z-isomer which showed higher DNA-cleaving efficiency.

Photoisomerization as a trigger for Bergman cyclization: synthesis and reactivity of azoenediynes.

Cyclic enediynes 1a and 2a containing stable E-azo moiety (azoenediynes) have been synthesized. These compounds upon irradiation with long wavelength UV isomerize to the Z-compounds 1b and 2b, which can be thermally reisomerized to the Z compounds. Reactivity studies toward BC using DSC predictably indicate higher reactivity for the Z-isomers. Our studies may provide a novel way to modulate the reactivity of enediynes under thermal or photochemical conditions.

Dependence of reactivity of a novel 2,6-diamino pyridine-based enediyne on the extent of salt formation with external acids: a possible implication in pH based drug design.

A novel pyridine diamine-based cyclic enediyne 1 was synthesized by bis-N-alkylation of 2,6-bis-sulfonamido pyridine 6 followed by deprotection with thiophenol. A variety of salts 1a-c of the parent amine 1 were prepared. Thermal reactivity studies indicated a dependence of the reactivity upon the extent of salt formation. This observation may be useful in pH-based design of enediynes.