Simulations of NaCl Aggregation from Solution: Solvent Determines Topography of Free Energy Landscape

Patel, Lara A.; Kindt, James T.

doi:10.1002/jcc.25554

Cited by 16 publications

(13 citation statements)

References 74 publications

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“…The solute acts as scatterers in this measurement; that is, when the concentration of NaCl is high enough, ion clusters are created, and the effective cluster size also increases. [27,28]. We adjusted the NaCl concentration heuristically to acquire sufficient amplitude of flow signals.…”

Section: Measurements and Discussionmentioning

confidence: 99%

Image-Free Ultrasound Blood-Flow Monitoring Circuit System with Automatic Range-Gate Positioning Scheme: A Pilot Study

Park¹,

2021

Applied Sciences

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This work proposes a proof-of-concept ultrasound blood-flow-monitoring circuit system using a single-element transducer. The circuit system consists of a single-element ultrasonic transducer, an analog interface circuit, and a field-programmable gate array (FPGA). Since the system uses a single-element transducer, an ultrasound image cannot be reconstructed unless scanning with mechanical movement is used. An ultrasound blood-flow monitor basically needs to acquire a Doppler sample volume by positioning a range gate at a vessel region on a scanline. Most recent single-transducer-based ultrasound pulsed-wave Doppler devices rely on a manual adjustment of the range gate to acquire Doppler sample volumes. However, the manual adjustment of the range gate depends on the user’s experience, and it can be time consuming if a transducer is not properly positioned. Thus, automatic range-gate-positioning is more desirable for image-free pulsed-wave Doppler devices. This work proposes a circuit system which includes a new automatic range-gate-positioning scheme. It blindly tracks the position of a blood vessel on a scanline by using the accumulation of Doppler amplitude deviations and a hysteresis slicing function. The proposed range-gate-positioning scheme has been implemented in an FPGA for real-time operation and is based on addition-only computations, except for filter parts to reduce the complexity of computation in the hardware. The proposed blood-flow-monitoring circuit system has been implemented with discrete commercial chips for proof-of-concept purposes. It uses a center frequency of 2 MHz and a system-clock frequency of 20 MHz. The FPGA only utilizes 5.6% of slice look-up-tables (LUTs) for implementation of the range-gate-positioning scheme. For measurements, the circuit system was utilized to interrogate a customized flow phantom model, which included two vessel-mimicking channels. The circuit system successfully acquired Doppler sample volumes by positioning a range gate on a fluid channel. In addition, the estimated Doppler shift frequency shows a good agreement with the theoretical value.

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Section: Measurements and Discussionmentioning

confidence: 99%

Image-Free Ultrasound Blood-Flow Monitoring Circuit System with Automatic Range-Gate Positioning Scheme: A Pilot Study

Park¹,

2021

Applied Sciences

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“…For our purpose, selected micelle sizes (including 1,3,8,9,14,15,19,20,24,25,29,30,34,35,39,40,44,45,49,50,54,55,59, 60, 64, 65, 69, 70, 74, 75, 79, 80) were chosen to perform BAR analysis.…”

Section: Peach-bar Analysismentioning

confidence: 99%

“…3 Statistical thermodynamics shows that applying the law of mass action directly to simulations of small systems results in distortions to the size distribution and unimer concentration, 4 as has been confirmed recently in coarse-grained simulations of surfactants. 5 We have reported a new method to extract cluster free energy profiles and cluster size distributions from MD simulations of few clusters for several systems [6][7][8][9] including the zwitterionic surfactant octyl phosphocholine (OPC). 6 This method, dubbed "PEACH" standing for "Partition-enabled Analysis of Cluster Histograms," finds the globally optimized set of equilibrium association constants for all cluster sizes through an iterative fitting for the cluster size distributions observed in simulations.…”

Section: Introductionmentioning

confidence: 99%

Free energy of micellization of dodecyl phosphocholine (DPC) from molecular simulation: Hybrid PEACH‐BAR method

Zhang

Kindt

2021

J Comput Chem

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A new method to extract the free energy of aggregation versus aggregate size from molecular simulation data is proposed and applied to a united atom model of the zwitterionic surfactant dodecyl phosphocholine in water. This system's slow dissociation rate and low critical micelle concentration (CMC of approximately 1-2 mM) make extraction of cluster free energies directly from simulation results using the "partition-enabled analysis of cluster histogram" (PEACH) method impractical. The new approach applies PEACH to a model with weakened attractions between aggregants, which allows sampling of a continuous range of cluster sizes, then recovers the free energy of aggregation under the original fully-attractive force field using the BAR free energy difference method. PEACH-BAR results are compared with free energy differences calculated via umbrella sampling, and are used to make predictions of CMC, average cluster size, and SAXS scattering profiles that are in fair agreement with experiment.

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“…mengalami persaingan dengan proses Solvay. Diawal tahun 1800-an, penyelidikan dilakukan pada industri tersebut yaitu dilakukannya reaksi dekomposisi ganda antara NaCl (47)(48)(49)(50)(51)(52)(53)(54)(55) dengan NH 4 HCO 3 , namun tidak berhasil. Pada akhirnya Ernest solvay Belgia (1838 -1932) membawa perkembangan proses Solvay ini ketitik kesuksesan yaitu pada tahun1861 -1865.…”

Section: Pendahuluanunclassified

Natrium Karbonat : Termodinamika dan Transport Ion

Jumalia¹,

Zainul²

2019

Preprint

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Natrium Karbonat merupakan salah satu garam natrium dari asam karbonat yang bersifat higroskospis. Natrium Karbonat biasanya dapat digunakan dalam pembuatan kaca. Sintesis Natrium karbonat dapat dilakukan dengan proses Leblanc dan Solvay. Tujuan dari review ini untuk mengetahui termodinamika dan transport ion pada senyawa natrium karbonat. Metode yang digunakan yaitu studi literatur menggunakan endnote X7, pemodelan komputasi menggunakan ChemOffice 15.0, dan perhitungan matematis. Metode dengan studi literatur dapat dilihat pada fishbone. Metode menggunakan ChemOffice 15.0, pada minimize energy dihasilkan energi -271.9263 kcal/mol pada suhu optimum dengan bend nya yaitu 4.4521. Pada metode perhitungan matematis ada beberapa parameter transport ion yang dapat dihitung yaitu konduktivitas, viskositas, mobilitas ion, dan kecepatan hanyut. Parameter ini selain didapatkan dari perhitungan matematis juga dari data hasil review jurnal penelitian yang berkaitan. Hasil perhitungan pada konduktivitas yaitu 0,07905 x 10-8 mho/cm. Nilai viskositas natrium karbonat yaitu . Kelarutan natrium karbonat anhidrat pada suhu 20OC yaitu 2.533 g/cm3 .Sifat termokimia pada natrium karbonat ini yaitu Cp, So, ΔfHo ,ΔfG, masing-masing bernilai 109,2 J/mol·K; 136,4 J/mol·K; -1131 kJ/mol ; -1047,5 kJ/mol.

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Simulations of NaCl Aggregation from Solution: Solvent Determines Topography of Free Energy Landscape

Cited by 16 publications

References 74 publications

Image-Free Ultrasound Blood-Flow Monitoring Circuit System with Automatic Range-Gate Positioning Scheme: A Pilot Study

Image-Free Ultrasound Blood-Flow Monitoring Circuit System with Automatic Range-Gate Positioning Scheme: A Pilot Study

Free energy of micellization of dodecyl phosphocholine (DPC) from molecular simulation: Hybrid PEACH‐BAR method

Natrium Karbonat : Termodinamika dan Transport Ion

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