Physics Commons^™

Effective Two- And Three-Body Interactions Between Dressed Impurities In A Tilted Double-Well Potential, F. Theel, A. G. Volosniev, D. Diplaris, F. Brauneis, S. I. Mistakidis, P. Schmelcher

Physics Faculty Research & Creative Works

We explore the impact and scaling of effective interactions between two and three impurity atoms, induced by a bosonic medium, on their density distributions. To facilitate the detection of mediated interactions, we propose a setup where impurities are trapped in a tilted double-well potential, while the medium is confined to a ring. The tilt of the potential breaks the spatial inversion symmetry allowing us to exploit the population of the energetically elevated well as a probe of induced interactions. For two impurities, the interaction with the medium reduces the impurity population at the energetically elevated well, which we interpret as …

Bound Deuteron-Antideuteron System (Deuteronium): Leading Radiative And Internal-Structure Corrections To Bound-State Energies, Gregory S. Adkins, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

We evaluate the energy levels of the deuteronium bound system, which consists of a deuteron and an antideuteron, with a special emphasis on states with nonvanishing orbital angular momenta. The excited atomic bound states of deuteronium constitute probes for the understanding of higher-order quantum electrodynamic corrections for spin-1 particles in a bound system where the typical field strength of the binding Coulomb field (at a distance of the generalized Bohr radius) exceeds Schwinger's critical field strength. For states with nonvanishing angular momenta, effects due to the internal structure of the deuteron and virtual annihilation contributions are highly suppressed. Relevant transitions …

Meshless Discrete Velocity Boltzmann Model For Porous Media Flow, Amandine Maidenberg

Doctoral Dissertations and Master's Theses

This dissertation explores the combination of two sophisticated techniques for addressing computational fluid dynamics: the discrete velocity Boltzmann equation (DVBE) and the localized collocation meshless model with upwinding (U-LCMM). The DVBE is a high-level model that describes the foundations of transport phenomena by addressing the microscale motions of particles themselves and the effect of their aggregate behaviors on continuum principles. This equation integrates multiple scales of phenomena; while it can be used for fluid flow at Navier-Stokes scales, it can also resolve fine features that can only be described at the molecular level. This type of model is necessary for …

Active Measurement Of A Micron-Order Gap Under High-Speed And High-Temperature Conditions, Andrew Becker

Doctoral Dissertations and Master's Theses

The hypersonic regime poses numerous challenges that researchers face in the development of hypersonic flight vehicles. Due to their excellent thermomechanical properties, ultra-high-temperature ceramics (UHTCs) have risen as a promising solution to act as a protective barrier between the harsh environment and surface materials of these flight bodies. The mechanical operation of a portable hypersonic simulation device was developed in-house and tested at Argonne National Laboratories (ANL) to gather in-situ material response of prospective UHTC samples when exposed to a hypersonic regime. An edge detection-based algorithm was developed and used in LabVIEW to monitor the health and operation of the …

Study Of The Ic 443 Region With The Hawc Observatory, R. Alfaro, C. Alvarez, M. Araya, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, S. Groetsch, P. Hüntemeyer, M. Najafi, R. Turner, Et. Al

Michigan Tech Publications

Supernova remnants are one potential source class considered a PeVatron (i.e., capable of accelerating cosmic rays above PeV energies). The shock fronts produced after the explosion of the supernova are ideal regions for particle acceleration. IC 443 is a supernova remnant that has been studied extensively at different wavelengths. Using 2966 days of gamma-ray data from the High Altitude Water Cherenkov (HAWC) observatory, we study the emission of IC 443 with the objective of finding signatures of cosmic-ray acceleration at the PeV scale. Using a maximum likelihood method, we find a point source located at (α=94.°42, δ=22.°35) that we associate …

Analytical Solutions For Transitional Flow Around Hydrometeors: Implications For Particle Dynamics And Atmospheric Modeling, Ahmad Talaei, Timothy J. Garrett

Physics Student Research

Accurate modeling of hydrometeor dynamics is critical for advancing weather and climate predictions. However, this remains a long-standing challenge in atmospheric science, particularly within the transitional Reynolds number regime, due to the lack of analytical solutions to the Navier–Stokes equations. This study presents two analytical solutions for two-dimensional, incompressible, and viscous flow around a sphere, addressing the gap between low and high Reynolds number regimes. The first framework, an extension of classical expansion methods using hypergeometric, provides a direct analytical relation that characterizes separation angle across the transitional regime. To address post- separation dynamics, a second formulation based on a …

Competition Of Light-And Phonon-Dressing In Microwave-Dressed Bose Polarons, G. M. Koutentakis, S. I. Mistakidis, F. Grusdt, H. R. Sadeghpour, P. Schmelcher

Physics Faculty Research & Creative Works

We theoretically investigate the stationary properties of a spin-1/2 impurity immersed in a one-dimensional confined Bose gas. In particular, we consider coherently coupled spin states with an external field, where only one spin component interacts with the bath, enabling light dressing of the impurity and spin-dependent bath-impurity interactions. Through detailed comparisons with ab-initio many-body simulations, we demonstrate that the composite system is accurately described by a simplified effective Hamiltonian. The latter builds upon previously developed effective potential approaches in the absence of light dressing. It can be used to extract the impurity energy, residue, effective mass, and anharmonicity induced by …

Gravitational Perturbations And Quantum Field Interactions In Modified Spacetime Backgrounds, Abhishek Rout

Theses and Dissertations

This dissertation presents a study of gravitational perturbations and quantum field dynamics in modified spacetime backgrounds. The research is motivated by the quest to understand how quantum fields behave in curved spacetimes, particularly when extensions to general relativity, such as Chern--Simons modifications, are introduced.

The first part examines quantum field interactions with oscillating solitonic backgrounds, inspired by breather-type solutions of the sine--Gordon equation. Fermion bound states are shown to undergo destabilization due to the oscillatory background, leading to particle production and flux propagation to infinity. These results highlight the challenges of maintaining localized fermionic states in time-dependent topological backgrounds.

The …

Tess Light Curves And Period Changes In Low-Mass Eclipsing Binary Bb Persei, Marek Wolf, Petr Zasche, Miloslav Zejda, Martin Mašek, Andrej Mudray, Hana Kučáková, Waldemar Ogłoza, Jaroslav Merc, Jan Kára, Vojtěch Dienstbier

Physics & Astronomy Faculty Publications

We present a detailed analysis of the low-mass detached eclipsing binary system BB Persei, which contains two K-type stars in a circular orbit with a short period of 0.4856 d. We used light curves from the Transiting Exoplanet Survey Satellite (Tess), which observed BB Per in five sectors, to determine its photometric properties and a precise orbital ephemeris. The solution of the Tess light curve in Phoebe results in a detached configuration, where the temperature of the primary component was fixed to T 1 = 5 300 K according to Lamost, which gives us T 2 = 5 050 ± …

Six New Doubly Eclipsing Quadruples In A 2+2 Architecture, Petr Zasche, Hana Kučáková, Jan Kára, Jaroslav Merc, Z. Henzl, Martin Mašek, L. Červinka, Vojtěch Dienstbier

Physics & Astronomy Faculty Publications

The study presents a confirmation of six quadruples with two sets of eclipses that have the 2+2 architecture. These so-called doubly eclipsing systems still present a quite rare group of stars. We collected all available photometric data and carried out a detailed analysis of them. In addition to the precise TESS photometry used to model the light curves for both inner eclipsing binaries, photometric survey data were also used, and more than 100 nights of our own dedicated observations were carried out. These were mainly used for the detection of the long-term evolution of orbital periods. Thanks to these data, …

Construction, Optimization, And Characterization Of An Undergraduate Cold Cathode Table-Top Electron Accelerator For Radiation Physics Education, Caitlin Balmer, Mason Skeath, Mehran M. Zaini, Peter Zencak, Erin M. Craig

Journal of the Symposium of University Research and Creative Expression

Project Mentor(s): Mehran Zaini, PhD; Peter Zencak

Rising cancer cases spurred advancements in radiation therapy modalities, including electron accelerators. In this report, descriptive and diagnostic analysis was utilized to develop and characterize a functional, low energy cold cathode table-top electron accelerator for radiation physics experimentation in Central Washington University’s (CWU) undergraduate radiation lab. The device features a tungsten cathode (TC), brass anode, and copper Faraday Cup (FC) in a vacuum, enclosed by blue-tinted polyvinyl chloride (PVC). TC electron emission was facilitated by applied electric fields from input voltages of 1000 V to 5000 V. FC collected electron current in the …

Synthesis Of Nitrogen-Enriched 3d Graphene Foam For Electrochemical Sensing Of Hydrogen Peroxide (H₂O₂), Bhargavi Dronavalli, Madhava Rao Vallabhaneni, Jatla Murali Prakash, Deepti Kolli, Dandamudi Srilaxmi

Karbala International Journal of Modern Science

In this work, A simple hydrothermal process was utilized to create 3D-foam-type Nitrogen-doped graphene (NDG). The synthesized material was characterized using a range of physicochemical characterization techniques. These techniques confirm that nitrogen is successfully incorporated into the carbon network, resulting in NDG. Cyclic voltammetry (CV) investigation demonstrated that NDG-modified glassy carbon electrode (NDG/GCE) displayed finite charge transfer properties against typical redox systems. NDG/GCE is identified as a simple, facile, and efficient electrocatalyst material for the estimation of hydrogen peroxide (H₂O₂). From CV analysis, it is revealed that NDG/GCE can produce a signal for electrochemical quantification of …

Plasmonic Nanoparticle Integration On Fiber Optic: Role Of Organic Linker And Functionalization Length In Refractive Index Sensing, Shela Ilmiyah, Mohamad Syahadi, Muflikhah Muflikhah, Yuwana Pradana, Zainul Arifin Iman Supardi, Iwan Darmadi, Lia Aprilia

Makara Journal of Science

Nanoplasmonic fiber optic sensors leverage the optical fiber’s inherent compactness and surface sensitivity via evanescent-field interactions with the localized surface plasmon resonance of the metallic nanoparticles. One of the popular approaches is self-assembly owing to its relatively low cost. Despite its low cost, the self-assembly technique has low reproducibility and exhibits low sensitivity because of low nanoplasmonic coverage on the fiber optic surface. In this study, several fabrication techniques were explored to assess the refractive index sensitivity by comparing three common organosilanes, i.e., (3-Aminopropyl)triethoxysilane (APTES), (3-Aminopropyl)trimethoxysilane, and (3-Mercaptopropyl)trimethoxysilane. Comparative analyses assessed the anchoring efficiency of the three silanes, sensor reproducibility, …

Hawc, Veritas, Fermi-Lat, And Xmm-Newton Follow-Up Observations Of The Unidentified Ultra-High-Energy Gamma-Ray Source Lhaaso J2108+5157, C. B. Adams, P. Bangale, W. Benbow, J. H. Buckley, Y. Chen, J. L. Christiansen, S. Groetsch, P. Hüntemeyer, M. Najafi, R. Turner, X. Wang, Et. Al

Michigan Tech Publications

We report observations of the ultra-high-energy gamma-ray source LHAASO J2108+5157, utilizing VERITAS, HAWC, Fermi-LAT, and XMM-Newton. VERITAS has collected ∼40 hr of data that we used to set ULs to the emission above 200 GeV. The HAWC data, collected over ∼2400 days, reveal emission between 3 and 146 TeV, with a significance of 7.5σ, favoring an extended source model. The best-fit spectrum measured by HAWC is characterized by a simple power law with a spectral index of 2.45 ± 0.11stat. Fermi-LAT analysis finds a point source with a very soft spectrum in the LHAASO J2108+5157 region, consistent with the 4FGL-DR3 …

Synthesis And Characterization Of Fe-Zn Bimetallic Nanoparticles Via Two-Step Laser Ablation And Their Antibacterial Activity, Hudhaifa M. Mohammed, Sahar Naji Rashid

Karbala International Journal of Modern Science

In this study, Nd: YAG laser at a wavelength of (1064 nm), energies of (300 and 400 mJ), and a pulse repetition rate of (3 Hz) was used to synthesize metallic nanoparticles from iron and zinc individually using a one-step pulsed laser ablation approach, followed by the two-step synthesis of bimetallic nanoparticles. The physical properties of the synthesized nanoparticles were then investigated using UV-visible (UV-Vis), X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and energy-dispersive X-ray (EDX) techniques. The results of characterization of the obtained NPs confirmed the formation of core-shell nanocomposites, as evidenced by the increased absorbance intensity of …

Effect Of Varying Chitosan Molecular Weights On The Morphology And Physical Characteristics Of Pva/Chitosan Composite Hydrogels, Yuan Alfinsyah Sihombing, Halida Rahmi Luthfianti, William Xaveriano Waresindo, Marathur Rodhiyah, Nur’Aini Nafisah, Dian Ahmad Hapidin, Dhewa Edikresnha, Khairurrijal Khairurrijal

Makara Journal of Science

We employed the innovative freeze–thaw method to investigate the effect of chitosan (CS) molecular weights incorporated into polyvinyl alcohol on the morphology and physical characteristics of the hydrogel. This study aimed to unravel the intricate relationships between CS molecular weight variations, CS concentration, and the number of freeze–thaw cycles (4 or 6 cycles) on hydrogel swelling degree and weight loss. Incorporating CS improved the hydrogel structure and enhanced its porosity, resulting in remarkable increases in swelling degree ranging from 2 to 6 times the initial weight. Higher molecular weight CS (310,000–375,000 Da) exhibited a lower swelling degree than medium molecular …

Modeling-Based Prediction Of Current Oscillation With The Josephson Frequency In Voltage-Biased Phase-Slip Center Filaments, Armen Gulian

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this article, we demonstrate that the voltage-biased phase-slip center (PSC) can act as a direct equivalent (not merely an analogy) of the Josephson effect in Josephson junctions (JJs). We analyze the behavior of PSCs in the case when a constant voltage V is applied to the superconducting filament. The analysis is performed using finite element modeling on the basis of time-dependent Ginzburg–Landau (TDGL) equations. It reveals that the current in the filament oscillates with the Josephson frequency ω = 2eV/h. This fact may have important corollaries in practice.

Solutions For Linear Fractional Differential Equations With Multiple Constraints Using Fractional B-Poly Bases, Md. Habibur Rahman, Muhammad I. Bhatti, Nicholas Dimakis

Physics & Astronomy Faculty Publications

This study presents an innovative numerical method for solving linear fractional differential equations (LFDEs) using modified Bernstein polynomial bases. The proposed approach effectively addresses the challenges posed by the nonlocal nature of fractional derivatives, providing a robust framework for handling multiple initial and boundary value constraints. By integrating the LFDEs and approximating the solutions with modified fractional-order Bernstein polynomials, we derive operational matrices to solve the resulting system numerically. The method’s accuracy is validated through several examples, showing excellent agreement between numerical and exact solutions. Comparative analysis with existing data further confirms the reliability of the approach, with absolute errors …

Enhancing Science Learning Outcomes With Sitaya Miniature Media: A Quantitative Study Of Elementary Education, Gilang Kripsiyadi Praramdana, Hamdan Hamdan, Agus Gunawan, Fauziah Dwi Hijriani

Jurnal Pendidikan Sains

This study investigates the impact of SITAYA Miniature media on the learning outcomes of grade VI students in science subjects at SDN 2 Darma. Conventional teaching methods, often less engaging for students, were identified as a significant factor contributing to low academic performance. The study employed a quantitative research approach, with a randomized sample of 43 students divided into an experimental group (24 students) and a control group (19 students). Pretest and posttest data were collected using a structured test instrument, and statistical analyses, including normality, homogeneity, t-tests, and N-Gain tests, were conducted to assess the effectiveness of SITAYA Miniature …

Beta Particles Impact On The Optical Properties Of Tio₂ Thin Films, Farah S. Dakhil, Hassan M.Jaber Al-Ta’Ii

Al-Bahir

TiO₂ is a semiconductor with a wide band gap and is utilized in various applications, including photovoltaics, solar cells, and photocatalysis. In this work, TiO₂ thin films were fabricated using the doctor blade technique and deposited onto glass substrates. The purpose of the study was to investigate how beta irradiation affected the optical properties of the TiO₂ films. The produced samples' absorbance and photon energy were the main subjects of the measurements. While the samples exposed to beta rays for 30, 60, and 90 minutes had direct band gaps of 3.87 eV, 3.75 eV, and 3.66 eV, …

Eng- Semicon: Understanding Nanoscale Heat Transport In Wide- And Ultrawide Bandgap Semiconductors Using Novel Deep Ultraviolet Tools, Joshua Lee Knobloch

Funded Research Records

No abstract provided.

Click-Ready Gold Nanoparticles From Aqueous Mechanochemistry: 2-Propynylamine As A Reducing Agent And Surface Ligand, Amber L. Garcia, Brian S. Mitchell, Amanda Reusch, Mark J. Fink, Juan P. Hinestroza, Yelin Ko, Julie P. Vanegas

Physics & Astronomy Faculty Publications

We report a rapid aqueous method for synthesizing monodisperse gold nanoparticles (AuNPs), employing 2-propynylamine as both an intrinsic reducing agent and a surface-stabilizing ligand. This self-mediated process—achieved in a single step—yields spherical AuNPs with an average diameter of 4.0 ± 1.0 nm and a well-defined localized surface plasmon resonance band centered at 520 nm. Acting as a bifunctional molecule, 2-propynylamine simultaneously reduces HAuCl4·3H2O to elemental gold and passivates the nanoparticle surface through coordination via the amine group, while preserving a terminal alkyne (–C≡CH) functionality. This reactive moiety remains exposed and chemically accessible, enabling post-synthetic modification through Cu(I)-catalyzed azide–alkyne cycloaddition. Control …

Correlation Of Radon Gas Concentrations And Associated Radiological Risks In Soil Using Ssntds With Gis And Spss At Najaf Governorate, Iraq, Rafal Mohamed Abdulsada, Lubna A. Alasadi

Al-Bahir

All human beings are affected by soil directly or indirectly. This study focuses on the effect of radon gas and related radiological risks using SSNTDs, specifically CR-39 detectors, in eighty secondary schools in Najaf and Kufa cities, Najaf Governorate, Iraq. As we recognize the importance of soil and its strong connection to humans, the study focused on areas where public and private schools were built, where students are present, and the potential for radiation risks to affect students' health. The results show that the average concentrations of C, C_Rn were 64.329±59.149 Bq / m³ and 3150.699±2897.036 Bq / …

Green Synthesis Of Copper And Silver Nanostructured Particles From Eremurus Plant Extract And Comparison Of Their Optical Properties And Antibacterial Activities, Doaa Ayad Kamil, Ali F. Al-Rawaf, Mohammed Yarub Hani, H.H. Obeed, Tabarek Falah Deindee, Mohammed Ridha Shaeed

Karbala International Journal of Modern Science

In the present investigation, silver (Ag) and copper (Cu) nanostructured particles were synthesized from Eremurus plant by means of an environmentally benign methodology in which plant extracts served as both reducing and stabilizing agents. The resultant nanostructured particles were subjected to characterization techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDXS). XRD analysis confirmed development of Ag nanostructured particles with face-centered cubic (fcc) structure and also Cu nanostructured particles with cubic form. Moreover, the average crystallite dimensions obtained for Ag and Cu were 18.3 nm and 65.7 nm, …

Fabrication And Characterization Of Epoxy Resin Co-Doped With 2,5-Diphenyloxazole And Cerium Fluoride Nanoparticles For Radiation Detection, Akapong Phunpueok, Jaruwan Seangrit, Sarawut Jaiyen, Krittiya Sreebunpeng, Wuttichai Chaiphaksa, Kewalee Nilgumhang, Voranuch Thongpool

Karbala International Journal of Modern Science

This paper presents the fabrication and characterization of a plastic scintillator prepared from epoxy resin doped with 2,5-diphenyloxazole (PPO) and cerium fluoride nanoparticles (CeF₃ NPs) for radiation detection. The CeF₃ NPs were prepared by a chemical process and examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM); it was found that the prepared particles were true CeF₃ NPs with an average particle size of approximately 17 nm. The CeF₃ NPs were co-doped with PPO into epoxy resin and formed into a plastic scintillator of 3 cm in diameter and 2 cm in length. Analysis of …

Hybrid Path Planner For Centralized Multi-Robotic Long-Vehicle Based On Adaptive Dimensionality And Grey Wolf Algorithm, Noor Kadhim Ayoob, Ali Hadi Hasan

Karbala International Journal of Modern Science

The present robot planning methods pay no attention to the impact of the robot's size and the space it occupies in the environment on path planning. This paper presents a centralized hybrid method to plan optimal paths for multiple robotic long vehicles (RLVs) competing with each other to reach one common goal, taking into account the space that must be available to the RLV at each step to avoid narrow spaces that are too small to pass through. The environment analysis for each RLV is improved by assigning constant weight to the obstacles and calculating two new parameters: safety (SF) …

Unified Study Of The Classical Hall Effect, Carter J. Reed, Javier E. Hasbun, Wyatt E. Ackerman, L Ajith Desilva

Georgia Journal of Science

Germanium (Ge) samples with different doping types, acceptors (p-type) and donors (n-type), were studied to investigate charge carrier behavior. Carrier concentrations were found to be 1.16×10^21 m^(-3) for the p-type sample and 7.337×10^20 m^(-3) for the n-type sample. These experiments were conducted for the standard Hall effect (Hall voltage versus low magnetic field (B) values) as well as conductivity and Hall voltage versus temperature for different B-fields. The measurements versus temperature at zero-field allow us to obtain band gap ( Eg). While we investigate the conductivities for n-type and p-type doped samples, we also study the conductivity of an undoped …

Influence Of Variable Climate On Mechanical Properties Of Composite Materials: An Experimental Study, Alexandra Tazhibaeva, Safaa M.R.H. Hussein, Mikhail Kuznetsov, Farid Shakirzyanov, Nikita Kharin, Igor Muravyev, Timur Agliullin, Gulshat Saleeva, Victor Mitryakin, Oleg Morozov, Oskar Sachenkov

Karbala International Journal of Modern Science

This study investigates the degradation of carbon fiber-reinforced plastic composites, fabricated via non-autoclave molding, under tropical climatic conditions across three regions over three years. Forty specimens (10 control, 30 exposed) with 2x2 twill weave and 0°/90° fiber orientation were subjected to tensile and compressive testing, microscopy, and X-ray computed tomography. Control specimens established baseline properties, while exposed specimens underwent three-year weathering. Statistical and principal component analyses revealed significant mechanical degradation, with tensile strength decreasing by up to 16.1% (p

Impact Of Plasma-Activated Water On Breast Cancer Cell Viability, Maryam G. Jasim, Hammad R. Humud

Karbala International Journal of Modern Science

Plasma-activated water (PAW) was generated using a dielectric barrier discharge (DBD) plasma system operating with a 1:1 mixture of nitrogen and argon gases to evaluate its cytotoxic effects on MCF-7 breast cancer cells. Water samples were divided into five groups: 0 minutes (control), 5, 10, 15, and 20 minutes of plasma exposure. The resulting PAW was applied to cultured cells, and cell viability was assessed 24- and 48-hour post-treatment. Viability was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results showed an apparent time-dependent increase in cytotoxicity. At 24 hours, cell mortality rates were 1.9%, 40.7%, 48.1%, 53.6%, …

Engineered Biochar-Attapulgite Clay Composite: A Novel Slow-Release Phosphorus Fertilizer, Harleen Kaur, Gurwinder Singh, Marjana Yeasmin, Kavitha Ramadass, Puspamitra Panigrahi, Alan Larson, Ranjit Pati, Dane Lamb, Bo Zheng, Ehsan Tavakkoli, Lukas Van Zwieten, Ajayan Vinu

Michigan Tech Publications

Sustainable agricultural practices are in high demand, and the development of innovative materials for slow nutrient release holds utmost importance. Phosphorus (P) stratification limits plant P availability in no-till farming systems. To address this, a nano composite-based P fertilizer to release nutrients in the root zone following surface soil application is constructed. The nanocomposite fertilizers (BAP-SRFs) were formed by a combination of different amounts of biochar (BC), attapulgite clay (ATP) and KH2PO4, followed by a high-temperature treatment (500 °C). XANES analysis revealed the enrichment of the surface with carbon (C), oxygen (O) and P-containing functional groups, and the bond formation …