A consistent Thermodynamic Model for Solid Liquid Equilibrium (SLE) and Vapor Liquid Equilibrium (VLE) in Aqueous Amine Solutions

AbstractTwo thermodynamic models (NRTL/UNIQUAC) were tested to model the SLE and VLE of the aqueous piperazine system. The reported 6 species in solid and liquid phases were represented successfully together with the estimated standard enthalpies and Gibbs energy of formation. The earlier reported experimental data for different SLE and VLE were found to be very useful for this work. The models consistently represent the experimental data. However, efforts are still needed to improve the model and a direct measurement of the solution heat capacity will reduce the number of fitted parameters

The Influence of Influencers on Consumer Purchase Intention on the Instagram Social Media Platform

Endorsement merupakan salah satu jenis pemasaran yang menggunakan influencer untuk mengiklankan suatu produk atau layanan dengan memanfaatkan ketenaran dalam sebuah platform media sosial. Penelitian ini menganalisis pengaruh sumber komunikasi, kredibilitas dan daya tarik terhadap nilai iklan dan sikap konsumen yang pada akhirnya mempengaruhi niat pembelian. Pengambilan data dalam penelitian ini menggunakan metode kuantitatif yaitu teknik convenience sampling dengan menyebarkan kuesioner melalui google form kepada 180 responden yang memiliki kriteria berusia 16 tahun ke atas dan merupakan pengguna platform Instagram yang mengikuti akun Fadil Jaidi. Lebih lanjut, penelitian ini melakukan pengolahan data dengan menggunakan aplikasi SPSS dan PLS-SEM (SmartPLS). Hasil penelitian ini menunjukkan bahwa sumber komunikasi, kredibilitas dan daya tarik berpengaruh signifikan terhadap nilai iklan dan sikap konsmuen. Kemudian, nilai iklan dan sikap konsumen berpengaruh signifikan terhadap niat beli

Analisis Faktor: Validitas Konstruk Instrumen Penilaian Keterampilan Berpikir Kritis

Abstrak - Berpikir kritis merupakan keterampilan berpikir yang melibatkan proses bernalar dan berpikir reflektif yang tidak dapat diamati secara langsung, sehingga membutuhkan suatu instrumen penilaian tersendiri. Instrumen penilaian yang dapat digunakan untuk mengukur keterampilan berpikir kritis harus valid. Validitas suatu instrumen dapat diketahui dengan menggunakan validitas konstruk. Penelitian ini bertujuan untuk mengaplikasikan analisis faktor untuk menentukan validitas konstruk instrumen penilaian keterampilan berpikir kritis. Instrumen penilaian dikembangkan berdasar 4 faktor keterampilan berpikir kritis, yaitu penjelasan, analisis, simpulan, dan evaluasi. Instrumen penilaian mencakup materi gerak lurus dan gerak parabola yang diujicobakan sebanyak dua kali pada siswa SMA di Kabupaten Banyumas. Analisis faktor yang digunakan adalah analisis faktor dengan pengujian One-Sample Kolmogrov-Smirnov Test, uji asumsi KMO, Anti-Image Correlation, komunalitas, dan Total Variance Explained. Uji coba pertama dilakukan pada 109 siswa dengan hasil analisis menunjukkan bahwa dari 40 butir soal yang diuji terpilih 12 butir soal yang membentuk 4 faktor yang sesuai dengan faktor pada kajian teoritis dan nilai muatan faktor terbesar terdapat pada butir 7.1 sebesar 0,760 dan terkecil butir 10.4 sebesar 0,560. Uji coba kedua dilakukan pada 136 siswa dengan hasil analisis menunjukkan bahwa dari 12 butir soal yang sudah dipilih membentuk 4 faktor yang menguatkan hasil uji coba pertama dengan nilai muatan faktor terbesar terdapat pada butir 7.1 sebesar 0,884 dan terkecil butir 5.2 sebesar 0,443. Berdasarkan hasil tersebut maka instrumen penilaian keterampilan berpikir kritis yang terdiri dari 12 butir soal adalah valid ditinjau dari validitas konstruk

Prediction of N2O Solubility in Alkanolamine Solutions from the Excess Volume Property

AbstractThe CO2 solubility is very important property when establishing thermodynamic models for the VLE. In order to obtain the CO2 solubility the normal procedure is to use the N2O analogy as the CO2 solubility cannot be directly measured. This calls for a rather extensive experimental program. In this work a simple and less laborious model was developed based on the excess molar volumes to estimate the excess Henry's constant. This method only requires density data and the N2O solubility into pure solvents (Water/Alkanolamine). The model works well to represent experimental data for different temperatures and concentrations

CO2 capture using highly viscous amine blends in nonporous membrane contactors

New amine blends have shown a promising potential to reduce the energy penalty for CO2 capture in post combustion, making the deployment of carbon capture technologies one-step closer. However, their application at the industrial scale is threaten by their high volatility. Non-porous membrane contactors offer a viable solution to properly control amine emissions from these absorbents. In the present work, the CO2 capture performance of non-porous membrane contactors using new amine blends as liquid phase was investigated in a temperature range typical for the absorption step (25–60 °C). Different amine blends with promising features in terms of cycling capacity and regeneration energy requirement were selected as liquid absorbents. Thin composite membranes fabricated by coating a perfluoropolymer on the top of a porous polypropylene layer were used as the interface between the gas and the liquid. At room temperature, membrane contactors using new absorbents exhibit a lower CO2 mass transfer coefficient compared to the benchmark (30 wt% MEA), possibly due to the high viscosity of these liquids. The modelling analysis suggests that the liquid boundary layer dominates the mass transfer resistance in the temperature range up to 40 °C, but at higher temperatures, the decrease of the solvent viscosity makes the mass transfer dominated by the membrane phase. Interestingly, the new amine blends show better performance compared to the benchmark at higher CO2 concentrations in feed gas, highlighting a good potential to capture CO2 from concentrated flue gas from steel/cement industry or to upgrade biogas

Study on carbamate stability in the Amp/CO2/H2O system from 13C-NMR spectroscopy

AbstractQualitative and quantitative 13C NMR studies were performed on 30 wt % aqueous solution of 2-amino-2-methyl-1-propanol (AMP) with different amount of CO2 at 25 °C. The results suggested that the main species in this system are: AMP/AMPH+, AMPCO2− and HCO3−/CO32−. The carbamate was observed at low loading and the carbamate stability constant was calculated based only on the experimental species concentration from NMR analysis. Based on the liquid phase speciation from NMR, the carbamate stability constant on mol fraction basis was found to be about 0.47 at 25 °C

A systematic procedure for process energy evaluation for post combustion CO2 capture: Case study of two novel strong bicarbonate-forming solvents

Process simulation is used for energetic evaluation of two novel strong bicarbonate forming solvents for post combustion CO2 capture, intended for coal- and natural gas based exhaust streams. An evaluation framework has been developed where process energy sinks are coupled to process energy balances based on the basic principles of a thermal heat engine. This procedure enables coupling of detailed solvent properties, such as reaction enthalpy, VLE, and kinetics, with the overall process operation, while accounting for the magnitude of the energy sinks in the process. The method identifies areas where there may be room for potential improvement, shows how the fundamental chemical properties of the solvents give rise to the overall capture potential, and highlights interdependencies between major energy sinks in the process. This framework is then used to clarify where heat is spent in the process for two novel solvent systems: activated 2-Piperidineethanol (2-PPE) and 1-(2-Hydroxyethyl)pyrrolidine (1-(2HE)PRLD). These novel solvents are compared with a base case of MEA and Cesar1. Activated 2-Piperidineethanol showed the best performance for the process setup evaluated in this work. The regenerative efficiency parameter for this solvent is 66% with an optimum specific reboiler duty of 2.78 MJ/kg CO2 removed; a 22% reduction compared to MEA in the coal case. Furthermore, the solvent seems to be sufficiently fast to be used in an industrial absorber and is a promising system for post combustion CO2 capture. This results in a power plant specific energy penalty for avoided CO2 of 0.27 kWhel/kg CO2. The evaluation framework can also identify the potential for additional energy improvements by economizing configurations for improved internal heat distribution.acceptedVersio

Understanding precipitation in amino acid salt systems at process conditions

Rapid screening experiment has been used to acquire first-hand information on the precipitation characteristics of 14 aqueous amino acid salt systems. Absorption tests at 40°C have shown that at high concentrations, amino acid salt systems forms precipitate in the presence of CO2 resulting to 2 or 3 solid-liquid phase formation. Potassium salt of the amino acid salts generally showed better reaction kinetics than their sodium salt counterparts. 5m’ KSar and 4.3m’ KPro showed significantly higher reaction kinetics while 5m’ KSar, 5m’ KAla, 4.5m’ KSer, 5m’ KL-Ala were observed to have an upward shift in absorption rate at some point during absorption resulting to increased loading. Application of the conventional stripping process in the screening test, i.e. heating up the absorption solution to 80oC showed poor desorption characteristics for the precipitating amino acid salt solutions. Qualitative 13C NMR studies was used to identify the chemical species in the phases, 3-phase in 5m’ KSar and 2-phase in 4.5m’ KSer. The NMR results show that each phase contains HCO3 -/CO32- and carbamate fractions at varying degree.publishedVersio

Ketepatan dan Kecukupan Profilaksis Venous Thromboembolism berdasar Pedoman American College of Chest Physicians di Ruang Rawat Intensif Rumah Sakit DR. Hasan Sadikin Bandung Periode Januari–Desember 2016

Pasien sakit kritis adalah pasien dengan kondisi mengancam nyawa yang membutuhkan penanganan khusus di ruang rawat intensif (intensive care unit; ICU). Hampir semua pasien kritis yang dirawat di ICU memiliki beberapa faktor risiko yang meningkatkan venous thromboembolism (VTE). Venous thromboembolism merupakan komplikasi yang tersembunyi pada pasien sakit kritis yang dapat meningkatkan angka morbiditas dan mortalitas. Venous thromboembolism dapat dicegah dengan tromboprofilaksis yang sesuai dan adekuat. Pedoman pencegahan VTE dikembangkan dalam beberapa dekade salah satunya oleh American College of Chest Physicians (ACCP). Tujuan penelitian ini mengetahui kepatuhan berdasar ketepatan dan kecukupan pemberian tromboprofilaksis terhadap pedoman ACCP. Penelitian deskiripsi observasional retrospektif dilakukan pada Oktober–Desember 2018 terhadap 284 pasien yang dirawat di Unit Perawatan Intensif Rumah Sakit Dr. Hasan Sadikin Bandung periode Januari–Desember 2016. Secara keseluruhan proporsi pasien di ICU yang mendapatkan tromboprofilaksis, yaitu 36,1%. Angka kepatuhan pemberian profilaksis VTE di ICU berdasar pedoman ACCP adalah 21,5%. Pemberian profilaksis VTE yang tidak adekuat terdapat pada 12,4% pasien, sedangkan pemberian profilaksis yang tidak sesuai terdapat pada 2,2% pasien. Simpulan, kepatuhan pemberian tromboprofilaksis terhadap pedoman yang diterbitkan ACCP masih rendah. Adequacy and Accuracy of Venous Thromboembolism Prophylaxis based on American College of Chest Physicians Guideline at Intensive Care Unit of Dr. Hasan Sadikin General Hospital BandungCritically ill patients are patients with life-threatening conditions that require special treatment in the intensive care unit. Almost all critical patients admitted to the ICU have several risk factors that increase the occurrence of Venous thromboembolism (VTE). Venous thromboembolism is a hidden complication in critically ill patients that can increase morbidity and mortality. Venous thromboembolism can be prevented with appropriate and adequate thromboprophylaxis. Several thromboprophylaxis guidelines have been developed during the last decades, including the American College of Chest Physicians (ACCP) guideline. The purpose of this study was to determine the compliance to ACCP guideline by measuring the the accuracy and adequacy of thromboprophylaxis. This retrospective observational descriptive study was conducted from October–December 2018 on 284 patients treated in the Intensive Care Unit of Dr. Hasan Sadikin General Hospital Bandung. The overall proportion of patients in ICU who received thromboprophylaxis was 36.1%. The compliance rate of VTE prophylaxis in ICU based on ACCP guideline was 21.5%. Inadequate VTE prophylaxis was seen in 12.4% of patients while inappropriate prophylaxis was identified in 2.2% of patients. Hence, the compliance to standards on thromboprophylaxis based on the ACCP guideline is still low in this hospital. Pasien sakit kritis adalah pasien dengan kondisi mengancam nyawa yang membutuhkan penanganan khusus di ruang rawat intensif (intensive care unit; ICU). Hampir semua pasien kritis yang dirawat di ICU memiliki beberapa faktor risiko yang meningkatkan venous thromboembolism (VTE). Venous thromboembolism merupakan komplikasi yang tersembunyi pada pasien sakit kritis yang dapat meningkatkan angka morbiditas dan mortalitas. Venous thromboembolism dapat dicegah dengan tromboprofilaksis yang sesuai dan adekuat. Pedoman pencegahan VTE dikembangkan dalam beberapa dekade salah satunya oleh American College of Chest Physicians (ACCP). Tujuan penelitian ini mengetahui kepatuhan berdasar ketepatan dan kecukupan pemberian tromboprofilaksis terhadap pedoman ACCP. Penelitian deskiripsi observasional retrospektif dilakukan pada Oktober–Desember 2018 terhadap 284 pasien yang dirawat di Unit Perawatan Intensif Rumah Sakit Dr. Hasan Sadikin Bandung periode Januari–Desember 2016. Secara keseluruhan proporsi pasien di ICU yang mendapatkan tromboprofilaksis, yaitu 36,1%. Angka kepatuhan pemberian profilaksis VTE di ICU berdasar pedoman ACCP adalah 21,5%. Pemberian profilaksis VTE yang tidak adekuat terdapat pada 12,4% pasien, sedangkan pemberian profilaksis yang tidak sesuai terdapat pada 2,2% pasien. Simpulan, kepatuhan pemberian tromboprofilaksis terhadap pedoman yang diterbitkan ACCP masih rendah