bluuebunny/crossref_metadata_2025 huggingface dataset:
Suplementasi Hidrolisat Glukomanan Tepung Porang (Amorphophallus oncophillus) pada Produk Minuman Sinbiotik
Authors: Wirawati Chandra Utami , Nirmagustina Dwi Eva
Published: September 2022

Produk minuman sinbiotik merupakan kombinasi dari bakteri probiotik dan prebiotic yang dipercaya memberikan efek sinergis tidak hanya menghambat pertumbuhan mikroba pathogen dan meningkatkan pertumbuhan bakteri menguntungkan, akan tetapi juga berperan sebagai pangan fungsional. Penelitian ini bertujuan untuk mengkaji suplementasi hidrolisat glukomanan porang pada susu fermentasi. Rancangan penelitian yang diterapkan adalah Rancangan Acak kelompok Lengkap (RAKL) dengan kombinasi antara faktor konsentrasi hidrolisat glukomanan (0%, 0.5%, 1%, 1.5%) dan lama penyimpanan (0 hari, 30 hari, 60 hari) pada suhu 5oC. Peubah yang diamati adalah keasaman (pH), persen asam laktat, viskositas, viabilitas bakteri asam laktat (BAL) dan aktivitas antibakteri. Hasil penelitian menunjukkan bahwa suplementasi hidrolisat glukomanan porang menurunkan pH, akan tetapi meningkatkan total asam laktat dan viskositas  produk setelah penyimpanan 60 hari. Viabilitas bakteri asam laktat mengalami penurunan sebesar 4 siklus log selama penyimpanan, kecuali pada produk yang disuplementasi hidrolisat glukomanan 1% dan 1.5%.  Seluruh produk minuman sinbiotik memiliki aktivitas antibakteri terhadap mikroba pathogen yaitu E. coli ATCC 25922, S. aureus ATCC 25923, and S. Typhimurium ATCC 14028. Suplementasi hidrolisat glukomanan 1% dan lama penyimpanan 60 hari menghasilkan karakteristik minuman sinbiotik terbaik yaitu pH 3.45, total asam laktat 1.24%, viskositas 3.24 Cp, dan total BAL 8.69 CFU/g
The Diversity and Dominance of Weeds in Various Population Proportions of Intercropping Soybeans With Corn
Authors: Setiawan Agus Nugroho , Sarjiyah Sarjiyah , Rahmi Nur
Published: September 2022

Soybean is an important food crop for Indonesia after rice and corn. Soybean productivity in Indonesia is still low because most farmers use monoculture cropping patterns which has many weaknesses. Intercropping is an alternative to increase soybean productivity because it has many advantages. Soybeans can be intercropped with corn because the two plants have different physical characteristics, physiology and growth patterns. This research aimed to obtain information about the diversity and abundance of weeds in soybean and corn intercropping. The study was conducted using a single factor treatment design which will be arranged in a single plot field design, using Grobogan variety soybean and Bisma variety corn. The treatment was the proportion of soybean and corn populations which consisted of 4 proportions, i.e. 2:1, 3:1, 4:1, and 5:1, and monoculture soybeans were also planted as a control. Observations on weeds were carried out at the age of 2, 8, and 12 weeks after planting (before harvest) with vegetation analysis. The size of each sample is 0.5 m x 0.5 m with 15 sample plots/plots. The results showed that based on the summed dominance ratio (SDR) in the research area, 16 species of weeds were dominated by broadleaf weeds, with the dominant types of weeds being Phyllanthus urinaria L., Eleusine indica L., and Oryza sativa L. The results showed that based on the Summed Dominance Ratio (SDR) in soybean there were 16 species of weeds that were dominated by broadleaf weeds, with the dominant types of weeds being Phyllanthus urinaria L., Eleusine indica L., and Oryza. sativa L. Weeds growing on soybean intercropping with corn and soybean monoculture have a medium diversity index (H').
Factors Affecting The Smallholder Sugarcane Plantation Area
Authors: Jannah Eka Miftakhul , Rachmadhan Aditya Arief , Meidaliyantisyah Meidaliyantisyah , Hendra Jekvy
Published: September 2022

The decrease of the smallholder sugarcane area is the major problem for the Indonesian plantation white sugar industry. This study aims to analyze factors that affecting the decrease of the smallholder sugarcane area. This study uses a panel data econometric model; using cross-sectional data from five provinces of smallholder sugarcane base area (East Java, Central Java, Lampung, West Java, and Yogyakarta) with monthly time series from 2014 to 2018. Estimates use the generalized least square (GLS) method. The results showed that the decrease of the smallholder sugarcane area was significantly affected by: (1) the decrease of sugar factories that were actively operating, (2) the increase of labor wages in the estate crops sector, (3) land competition with corn commodities, and (4) the increase of residential areas due to growth of population. The opening of new sugar factories out of Java Island is an alternative to encourages land clearing for smallholder sugarcane areas.
Analisis Produksi dan Faktor Produksi Usaha Tani Terpadu Tanaman Padi dan Ternak Sapi di Nagari Taram Kecamatan Harau
Authors: Mukhlis Mukhlis , Hendriani Riva , Sari Regia Indah Kemala , Sari Nila
Published: September 2022

Pertanian Ramah Lingkungan dapat dikembangkan melalui sistem pertanian terpadu tanaman dan ternak. Adapun tujuan dari penelitian adalah untuk mengetahui gambaran produksi dan faktor produksi usaha tani terpadu tanaman padi dan ternak sapi. Penelitian ini menggunakan metode deskriptif, dimana dilakukan di Kabupaten Lima Puluh Kota tepatnya di Kecamatan Harau. Pemilihan daerah penelitian dilakukan dengan cara segaja. Penentuan sampel penelitian menggunakan metode pengambilan sampel bola salju. Pengumpulan data menggunakan metode wawancara menggunakan kuisioner untuk memperoleh data primer dan metode dokumentasi untuk memperoleh data sekunder. Metode analisis data menggunakan analisis deskriptif kualitatif dan kuantitatif menggunakan pendekatan teknik triangulasi yang menguji keabsahan data dengan metode, sumber, dan teori. Jumlah produksi padi yang dihasilkan oleh petani usaha tani terpadu tanaman padi dan ternak sapi di daerah penelitian berkisar antara 3.300 - 16.200 Kg. Namun rata-rata jumlah produksi padi yang dihasilkan adalah 6.940,88 Kg. Adapun faktor-faktor produksi dalam usaha tani padi usaha tani terpadu tanaman padi dan ternak sapi, meliputi: lahan sawah, kandang sapi, benih padi, bibit/bakalan ternak sapi, pupuk organik, pupuk anorganik, pakan ternak sapi, pestisida, obat dan vitamin ternak sapi, tenaga kerja dan modal.
Improving the efficiency of sanitation of urological catheters with various types of exposure to ultrasound emitters
Authors:   Omsk State Technical University, Novikov A. A. , Putintseva A. R. ,   Omsk State Technical University
Published: September 2022

The purpose of the article is to determine rational modes for safe and effective ultrasound exposure in order to sanitation urological catheters. It is shown that using an amplitude-modulated or pulsed power supply mode, it is possible to achieve an increase in amplitude, i.e. to improve the quality of cleaning and reduce heat generation. As a result, to technological solutions for the initiation of an ultrasonic emitter have been proposed.
Development of a mathematical model of magnetically controlled ferrovariometer control circuit
Authors:   Omsk State Transport University, Zaitsev V. V. , Fadeev K. S. ,   Omsk State Transport University, Avdeeva K. V. ,   Omsk State Transport University
Published: September 2022

The objective of this work is to develop a mathematical model for studying the magnetic control field of a magnetically controlled ferrovariometer in a linear approximation. This problem is solved on the basis of a plane-parallel model. The solution is based on the method of secondary sources. On the basis of the developed mathematical model, a program is compiled in a highlevel language that provides input of initial data and their printing, calculation of the coordinates of secondary sources and calculation of the initial approximate value of the associated currents, as well as iterative calculation of the system of equations with a given accuracy. The described method and program make it possible to obtain an approximate picture of the distribution of the control field in the design of a magnetically controlled ferrovariometer and in the surrounding space, if the design can be represented by a plane-parallel model. Based on the field calculation, it is possible to perform a parametric synthesis of the control circuit design and evaluate its interfering effect on the surrounding electrical circuits.
Improving the circuitry of high-precision high-speed acousto-optic laser interferometers of displacements with frequency matching of component blocks and double heterodyning at phototransformation stage
Authors:   Lavochkin Association, Leun E. V. , Shakhanov A. E. ,   Lavochkin Association, Samoilov S. Yu. ,   Lavochkin Association, Kolobov A. Yu. ,   Lavochkin Association
Published: September 2022

The article discusses the development of the circuitry of acousto-optic (AO) laser displacement interferometers (LDI) and the values of resolution and speed of controlled displacements achieved by them. The issues of frequency matching of blocks of AO LDI are discussed: AO modulator, photodetector device (FDD) and frequency generator. The features of phototransformation of the FDD under its illumination by three spatially combined optical streams are studied. Of these, two streams are of different frequencies, created as a result of diffraction in the AO modulator and are used to measure the phase shift from the controlled displacements of the object in the AO LDI. The third optical stream is amplitude-modulated with a frequency close to the difference frequency of the first two optical streams. This technique leads to a twofold transfer (double heterodination) of the phase shift from the offsets to the electrical signal of the difference frequency between the three optical streams. The schemes of AO LDI with a constant value of the frequency of the amplitude-modulated optical flow and with its auto-tuning are considered. The features of the use of cooled FDD in AO LDI are discussed.
A new approach to application of the method of measuring electric field strength by average value
Authors:   Omsk State Technical University, Tyukina L. V. , Biryukov S. V. ,   Omsk State Technical University, Tyukin A. V. ,   Siberian State Automobile and Highway University
Published: September 2022

The paper considers a new possibility of using the method of measuring the electric field strength by an average value in order to reduce the error from the inhomogeneity of the field and expand the spatial range of measurements. The studies carried out in the work allowed us to establish that when using the measurement method by the average value, there are always three values at each measurement step, two of which correspond to the two previous values of the EP intensity determined with errors opposite in sign, and the third corresponds to the average value of them. Therefore, in the work, it is proposed to measure the electric field strength at one point in space by two sensors with errors opposite in sign. At the same time, alternately determining at each step of averaging the average value of the EP intensity from the previously obtained and subsequent average values, bringing the measurement result closer to the true value. Based on the results of theoretical research, a new method is proposed — the "Measurement method with step-by-step averaging", which, without complicating the measurement process, makes it possible to reduce by two to three times the error in measuring the intensity of inhomogeneous electric fields in a wide spatial range compared with the measurement method by the average value.
Estimating efficiency of acoustic emission signal processing methods in implementation of polynomial digital filters
Authors:   ITMO University, Altay Ye. , Fedorov A. V. ,   ITMO University, Stepanova K. A. ,   ITMO University, Kuzivanov D. О. ,   ITMO University
Published: September 2022

The article presents a method for processing an acoustic emission (AE) signal to extract information and noise components from a noisy record. The method is based on digital filtering by polynomial models. To compensate for the introduced distortions by filters, a scheme for bidirectional processing of the AE signal is proposed. The operability of the filtering method for a noisy record is analyzed, and processing is evaluated on the basis of quantitative indicators. The evaluation results showed that the presented filtering method provides stability to the influencing noise and high accuracy of processing the AE signal recording when compared with the closest analogues.
Pursuit on the plane by objects moving away from the trajectory of defending object, with simulation of detection area
Authors:   Banzarov Buryat State University, Dubanov A. А. , Ausheev T. V. ,   East Siberia State University of Technology and Management
Published: September 2022

This article describes the model of pursuit of a single target by the method of chasing a group of objects. All objects participating in the pursuit model move with a constant modulo speed. The pursuing object moves along a certain trajectory and releases objects at specified intervals, the task of which is to overtake the target by the chase method. Released objects have restrictions on the curvature of the motion path. A single target, in turn, is tasked with overtaking the pursuer by the method of parallel approach. For each pursuing object, a detection area is formed. The detection area is formed by two beams. The object's velocity vector is the bisector of the angle formed by such rays. If the target enters the detection area, then the object begins the pursuit by the chase method. If the target leaves the detection area, then the object makes a uniform and rectilinear movement. The task is to implement a dynamic model of multiple group pursuit, where each object has its own tasks, which implements the chase method. The model is developed using computer mathematics systems. Based on the results of the research, animated images are created. As an example, where the model developed in the article could be in demand, the following can be given. There is considered the motion of a low-maneuverable object that is overtaking a faster target. As a means of protection, instead of releasing passive heat traps, it is proposed to drop a multitude of autonomously controlled weapons of destruction. From the analysis of the media, descriptions of such means of protection for aircraft have not been found. Modeling is carried out on a plane, there are no obstacles for modeling in space. The results of the research can be in demand in the design of unmanned aerial vehicles with elements of autonomous control and artificial intelligence.
The influence of lubricating coolant and processing modes on surface roughness during face milling of workpieces made of aluminum alloys
Authors:   Omsk State Technical University, Kisel A. G. , Makashin D. S. ,   Omsk State Technical University
Published: September 2022

Within the framework of these studies, experimental studies are carried out on the effect of using coolants of various types — synthetic «BIOSIL-S», semi-synthetic «SP3» and water-based «Smalta-4» — on the roughness of the machined surface of an aluminum billet during milling. The roughness of the machined surface is evaluated by the Ra parameter using a MarSurf PS1 portable profilometer. As a result of the research, it is found that coolants affect the quality of the resulting surface in different ways. The best surface quality is obtained at a cutting speed of V=283 m/min and a feed of S=0,02 mm/tooth using a BIOSIL-S coolant, which is due to rational cutting conditions and the physical properties of the coolant.
Investigation of the kinematics of mechatronic device drive based on a spatial mechanism
Authors:   Kazan National Research Technical University named after A. N. Tupolev – KAI, Khabibullin F. F. , Islamov R. T. ,   Kazan National Research Technical University named after A. N. Tupolev – KAI, Mustafaev T. A. ,   Kazan National Research Technical University named after A. N. Tupolev – KAI, Krymova V. N. ,   Kazan National Research Technical University named after A. N. Tupolev – KAI
Published: September 2022

In this paper, we consider the scheme of mechatronic device based on a spatial mechanism. The scheme is designed in such a way that the working elements are combined with the elements of the transmission mechanism — links. In the basis of design there are combined two basic modules with the discarding of the corresponding common links and the hinge, resulting in a new device. In addition, special attention is paid to values of absolute angular velocity and angular acceleration of a link for a particular point, also linear velocities and accelerations for each point of interest of a link from which the radius-vector and position of a point in space are determined. On the basis of the made calculations the scheme of an agitator with 4 links-blades, working bodies of which are combined with elements of a transfer mechanism, is proposed.
Simulation of dynamics of oscillations of manipulator using Lagrange equations of second order
Authors:   Omsk Tank-Automotive Engineering Institute, Shamutdinov A. H. , Lesnyak I. Yu. ,   Omsk State Technical University
Published: September 2022

The article discusses the main stages of compiling a dynamic model of manipulator oscillations, based on the method of mathematical modeling, the basis of which is the circuit design of the manipulator under study. A schematic solution of the manipulator has been compiled as a system in which an arbitrary vertical force Pz and moments Mx, My relative to the X and Y axes act on the working panel, elastic elements — springs, with known stiffness coefficients. On the basis of the equation of dynamics, in the form of Lagrange of the second order, a system of equations of oscillatory processes arising from external loads is compiled, natural frequencies of elastic oscillations of the manipulator are determined, and conclusions are drawn.
Designing technologies for life cycle of associated products and waste in process of preparing production of a new automotive component
Authors:   Naberezhnye Chelny Institute (branch) Kazan (Volga Region) Federal University, Safarova L. R. , Kasyanov S. V. ,   Naberezhnye Chelny Institute (branch) Kazan (Volga Region) Federal University, Safarov D. T. ,   Naberezhnye Chelny Institute (branch) Kazan (Volga Region) Federal University
Published: September 2022

The article presents an approach to minimizing the impact of automotive production on the natural environment, while minimizing the consumption of resources due to adequate planning of waste generation volumes in the workplace and the development of their life cycle processes at the stage of preparing the production of an automotive component. The algorithm of designing the manufacturing technology of automotive components with the development of processes for generating all types of associated products in the workplace is given. The blocks of calculation procedures are synchronized with the stages of preparation for the production of a new product in the automotive industry. A method of structuring the process has been developed, modeling of the content of intraoperative processes of creating a marketable product and the formation of time chains with subsequent planning for the removal of associated products, waste and emissions in the processes of functioning and maintenance of workplaces is carried out. Economic calculations are performed for decision-making by the engineering services of the enterprise.
Algorithm for diagnosing insulation of power transformers by acoustic method in conditions of temperature changes
Authors:   Omsk State Transport University, Kuznetsov A. A. , Kharlamov V. V. ,   Omsk State Transport University, Volchanina M. A. ,   Omsk State Transport University
Published: September 2022

The article presents an algorithm for processing data by the acoustic method of insulation power transformers. The article presents data processing of diagnosing by the acoustic method of power transformers. A feature of the power supply system of railway transport is the location of traction substations along the railway track. For diagnosing power transformers advisable to use portable systems based on acoustic monitoring of partial discharges due to their high mobility and ease of installation. To improve the reliability of diagnosis under the conditions of seasonal temperature changes proposed use a defect simulator and a differential method for measuring the parameters of partial discharges. The scheme of the experiment and the diagnostic algorithm are proposed. Expressions are given that describe the properties of transformer oil with temperature changes, and changes in signal parameters during the propagation of acoustic waves. The data of diagnostics obtained on a power transformer at positive and negative temperatures under conditions of development of an insulation defect accompanied by partial discharges are presented.
Determination of corrosion state of reinforced concrete structures by the parameters of color change in video image
Authors:   Omsk State Transport University, Kuznetsov A. A. , Ponomarev A. V. ,   Omsk State Transport University, Kuzmenko A. Yu. ,   Omsk State Transport University, Volchanin G. V. ,   Omsk State Transport University
Published: September 2022

The article shows one of the factors influencing the formation of corrosion of hollow reinforced concrete structures — leakage currents in insulators. The development of corrosion depends on the amount of electricity that has passed through the reinforced concrete. A method for controlling the corrosion state by changing the color parameters on the video image of the reinforced concrete surface is proposed. A full-scale experiment is carried out on samples simulating various degrees of corrosion, as well as on a sample with an unknown level of corrosion. The images are obtained using an industrial endoscope.
PERUBAHAN UNSUR HARA NITROGEN (N) DAN PHOSPHOR (P) TANAH GAMBUT DI LAHAN GAMBUT YANG DIPENGARUHI LAMA PENGOLAHAN LAHAN
Authors: Alhaddad Abdulmujib
Published: September 2022

Sejak 1987 petani memanfaatkan pukan ayam untuk meningkatkan ketersediaan  hara, sebelumnya mereka menggunakan limbah ternak babi. Keberadaan pukan ayam  diperlukan terutama agar sebagian kebutuhan hara makro dan mikro dapat dipenuhi.  Walaupun telah diketahui adanya perubahan sifat tanah gambut akibat penggunaan lahan untuk pertanian, tetapi jenis sifat-sifat tanah yang berubah dan besar perubahannya masih belum diketahui secara pasti. Penelitian bertujuan untuk mengetahui perubahan kandungan unsur Nitogen (N) dan Phosphor (P) tanah gambut yang dibudidayakan pada  praktek pengelolaan lahan gambut sejalan waktu pengelolaan. Penelitian ini dilakukan di lokasi lahan gambut Siantan, kota Pontianak pada bulan oktober hingga desember. Lahan gambut di Siantan diidentifikasi lama pengelolaannya, kemudian di kategorikan dalam empat(4) kelompok waktu pengolahan, yaitu tidak pernah diolah (TO), telah diolah kurang dari(<) 10 tahun (OLX), telah diolah selama 10-20 tahun (OLY), dan diolah selama 20-30tahun (OLZ). Pada setiap lahan pengelolaan dilakukan pengambilan contoh tanah dari delapan(8) titik  pengamatan yang berbeda untuk kemudian dilakukan pengukuran ketersediaan haranya. Pada setiap titik pengamatan diambil contoh tanah komposit dari lapisan 0-2 0cm, 20-40 cm dan 40-80 cm. Pada setiap titik pengamatan, diikuti dengan wawancara dengan petani pengelola lahan. Pengukuran ketersediaan Nitorgen dan Phosphor tanah gambut dilakukan dengan mengambil contoh tanah untuk keperluan analisis dilaboratorium. Analisis laboratorium dilakukan di Laboratorium Tanah Universitas Gadjah Mada. Hasil penelitian menunjukan Perbedaan karakteristik hara lahan gambut di Siantan akibat lama waktu pengolahan dan yang tidak diolah, hanya terjadi di lapisan olah 0-20cm dan lapisan 20-40cm. Perbedaan nyata antara lahan gambut yang tidak diolah dengan yang diolah terlihat pada karakteristik Nitrogen, Posphor. Perbedaan nyata pada Nitorgen dan Phosphor tanah di lahan gambut ini disebabkan pengolahan lahan yang intensif dengan masukan yang tinggi dari abu bakaran, busukan ikan dan kulit udang, kapur dan  pupuk urea. Secara umum lamanya waktu pengolahan tidak secara nyata memberikan perbedaan pada karakteristik lahan gambut Siantan. Pada lapisan 40-80cm pengaruh pengolahan dan lamanya waktu pengolahan tidak terlihat nyata pada Nitorgen dan Phosphor. Hal ini menunjukan pengaruh pengolahan lapisan atas sangat terbatas pengaruhnya pada lapisan yang lebih dalam. Tidak berbeda nyatanya pengaruh lamanya waktu pengolahan lahan gambut di Siantan, menunjukan adanya kestabilan keadaan hara pada lahan tersebut meskipun mendapat input hara yang intensif dalam waktu lama.
PENGARUH INOKULASI AZOTOBACTER DAN MIKORIZA ARBUSKULA TERHADAP PERTUMBUHAN BIBIT KARET
Authors: Maulidi Maulidi , Zulfita Dwi
Published: September 2022

Penelitian ini bertujuan mengetahui pengaruh inokulasi FMA, Azotobacter dan interaksinya terhadap pertumbuhan bibit karet serta mencari takaran FMA dan kepadatan Azotobacter yang terbaik terhadap pertumbuhan bibit karet. Penelitian ini dilaksanakan di kebun percobaan Fakultas Pertanian Untan Pontianak. Penelitian dilaksanakan dari Bulan Mei 2012 sampai dengan bulan Agustus 2012. Penelitian ini dilakukan dengan rancangan perlakuan faktorial 4 x 3 tata letak acak lengkap (CRD) dengan 3 ulangan.  Perlakuan Inokulasi Azotobacter terdiri dari 3 taraf yaitu Inokulasi A.chroococcum 2,5 x 103 CFU  mL-1 (k1), 5 x 103 CFU  mL-1 (k2), dan 10 x CFU  mL-1 pohon-1 (k3). Faktor inokulasi dengan Mikoriza Arbuskula (M) yang terdiri dari 4 taraf yaitu  tanpa inokulasi FMA (m­0), 2,5 g/polybag (m1), 5 g/polybag (m2) dan 10 g/polybag (m3). Percobaan diulang tiga kali. Variabel yang diamati dalam penelitian ini adalah kadar P dalam jaringan daun (%), luas daun (cm2), bobot kering daun (g) dan pertambahan panjang entris (cm). Hasil penelitian menunjukkan  bahwa inokulasi dengan berbagai takaran FMA meningkatkan pertumbuhan bibit karet. Inokulasi dengan FMA takaran 10 g/polybag meningkatkan pertumbuhan bibit karet yang terbaik. Inokulasi dengan Azotobacter juga dapat meningkatkan pertumbuhan bibit karet. Inokulasi dengan Azotobacter pada kepadatan  10 x 103 CFU mL-1bibit-1 cenderung menunjukkan pertumbuhan bibit karet yang terbaik. Tidak terjadi interaksi inokulasi  FMA dan Azotobacter dalam mempengaruhi pertumbuhan bibit karet.
Identification of single Ru(II) ions on ceria as a highly active catalyst for abatement of NOx pollutants
Authors: Khivantsev Konstantin , Jaegers Nicholas R. , Aleksandrov Hristiyan A. , Kovarik Libor , Engelhard Mark , Song Inhak , Tian Jinshu , Chen Linxiao , Meira Debora , Hernandez Xavier Isidro Pereira , Vayssilov Georgi N. , Wang Yong , Szanyi János
Published: September 2022

Atom trapping allows to prepare catalysts with atomically dispersed Ru ions Ru1O5 on (100) facets of ceria, as identified by EXAFS, infra-red spectroscopy and DFT calculations. This is a new class of ceria-based materials with Ru properties drastically different from the known M/ceria materials. They show excellent activity in industrially important catalytic NO oxidation reaction, a critical step that requires use of large loadings of expensive noble metals in diesel aftertreatment systems. Ru1/CeO2 catalysts are stable during continuous cycling, ramping and cooling as well as presence of moisture. Furthermore, Ru1/CeO2 shows unprecedentedly high NOx storage properties during cold start due to formation of stable Ru-NO complexes as well as high spill-over rate of NOx to the support. Only ~0.05 wt% of Ru is required to have excellent NOx storage. Single Ru ions forming Ru1O5 sites exhibit remarkably higher stability during calcination in air/steam up to 750 ºC in contrast to RuO2 nanoparticles that become volatile at temperature slightly above ambient. We clarify the location of Ru(II) ions on the ceria surface and experimentally identify mechanism of NO oxidation (as well as reactive storage) using DFT calculations and in-situ DRIFTS/Mass-spectroscopy measurements. Furthermore, we show the high reactivity of Ru1/CeO2 for NO reduction by CO: only 0.1-0.5 wt% of atomically dispersed Ru is sufficient to achieve high activity at low temperatures. With the aid of excitation-modulation in-situ infra-red measurements and XPS measurement, we uncover the individual elementary steps of NO reduction by CO on an atomically dispersed ceria-supported catalyst, highlighting the unique properties of Ru1/CeO2 catalyst and its propensity to form oxygen vacancies/Ce+3 sites that are critical for NO reduction even at low Ru loadings. Our study highlights the applicability of novel ceria-based single-atom catalysts to industrially relevant NO and CO abatement.
Open-Source Chromatographic Data Analysis for Reaction Optimization and Screening
Authors: Haas Christian P. , Lübbesmeyer Maximilian , Jin Edward H. , McDonald Matthew A. , Koscher Brent A. , Guimond Nicolas , Di Rocco Laura , Kayser Henning , Leweke Samuel , Niedenführ Sebastian , Nicholls Rachel , Greeves Emily , Barber David M. , Hillenbrand Julius , Volpin Giulio , Jensen Klavs F.
Published: September 2022

Automation and digitalization solutions in the field of small molecule synthesis face new challenges for chemical reaction analysis, especially in the field of high-performance liquid chromatography (HPLC). Chromatographic data remains locked in vendors’ hardware and software components limiting their potential in automated workflows and contradicting to FAIR data principles (findability, accessibility, interoperability, reuse), which enable chemometrics and data science applications. In this work, we present an open-source Python project called MOCCA (Multivariate Online Contextual Chromatographic Analysis) for the analysis of open-format HPLC–DAD (photodiode array detector) raw data. MOCCA provides a comprehensive set of data analysis features including a peak deconvolution routine which allows for automated deconvolution of known signals even if overlapped with signals of unexpected impurities or side products. We highlight the broad applicability of MOCCA in four studies: (i) a simulation study to validate MOCCA’s data analysis features; (ii) a reaction kinetics study on a Knoevenagel condensation reaction demonstrating MOCCA’s peak deconvolution feature; (iii) a closed-loop optimization study for the alkylation of 2-pyridone highlighting MOCCA’s potential to obviate the need for human control during data analysis; (iv) a well plate screening of categorical reaction parameters for a novel palladium-catalyzed cyanation of aryl halides employing O-protected cyanohydrins where MOCCA tracks all known and unknown signals. These studies emphasize how MOCCA enables its users to make data-based decisions in synthesis workflows with different degrees of automation by providing actionable analytics. By publishing MOCCA as a Python package together with this work, we envision an open-source community project for chromatographic data analysis with the potential of further advancing its scope and capabilities
GaTewAY : Graph theory based software for an automatic analyses of molecular conformers generated over time
Authors: bougueroua sana , Quessette Franck , Barth Dominique , Gaigeot Marie-Pierre
Published: September 2022

GaTewAY is a post-processing tool for molecular dynamics (MD) simulation databased on graph theoretical techniques. The main idea is to construct 2D graphs from the 3D structures. Then, GaTewAY identifies the conformations over time based on the dynamics of bonds and the isomorphism test. The use of graph theory methods/tools does not only provide a direct and fast methodology to identify conformers, but also allows following in time the interconversion reactions between the different conformers as shown by graphs of transitions. In this paper, we describe the methodology used to develop GaTeWAY. Then, we describe the code with its different modules. We present the inputs of GaTeWAY, the threshold values, the usage of the code and the main outputs. Our software has been tested and validated on DFT-MD and QM-MM trajectories of gas phase molecules and clusters. We will, in particular, illustrate results for peptides to have an idea about the outputs. The algorithm's transferability is further demonstrated on a more complex air/liquid water interface. We designed our algorithm so that it can be extended and consider any types of bonds/interactions and parameters; hence, GaTeWAY can be applied to any molecular system. Ongoing work aims to analyze reaction networks in clusters for catalysis. The results are promising. Another manuscript has just been submitted, which illustrates the performance of GateWAY for these systems.
Controlled dual functionalization of lignin generates unique properties in gelatin-based hydrogels
Authors: Bertella Stefania , Rana Vijay Kumar , Karami Peyman , Richter Lukasz , Stellacci Francesco , Pioletti Dominique , Luterbacher Jeremy
Published: September 2022

Uncontrolled side reactions during lignin fractionation lead to the loss of its chemical functionalities and the uncontrolled formation of unwanted structures. Because of these structural issues, functionalization steps are usually performed on residual active sites of isolated lignin in order to improve reactivity and/or miscibility towards other materials. Even with these additional steps, potential applications—especially high-performance applications—are generally substantially curtailed. In this work, we use aldehyde assisted fractionation (AAF) on this process with two multifunctional aldehydes to introduce multiple functionalities (aldehydes and carboxylic acids) on the lignin in a controlled way and in a single step from lignocellulosic biomass. We show that the quantity of the various functionalities can be easily monitored and tuned in order to impart different properties to the lignin in terms of reactivity and solubility. These bi-functional lignins were then employed in the fabrication of novel cross-linked gelatin-based hydrogels for soft tissue engineering. The resulting hydrogels showed enhanced and controllable mechanical (rheology, compressive and tensile), adhesive, temperature-resistant and self-healing properties but only when a bi-functional lignin was used. This work demonstrates the importance and potential of controlled multi-functionalization of lignin, opening the way for its use in high performance materials.
Computational study of the intercalation of NO2 between bilayer MoTe2
Authors: Szary Maciej Jan
Published: September 2022

Transition-metal dichalcogenide (TMD) layers have been a subject of widespread interest as chemical sensors with their sensitivity selectively enhanced depending on the number of layers. The effect has been linked to possible intercalation of species such as nitrogen dioxide (NO2). However, whether intercalation helps or even occurs remains speculative. Hence, this work investigates, employing density functional theory (DFT) calculations, the intercalation of NO2 between bilayers of molybdenum ditelluride (MoTe2), its energy, and the impact on charge transfer. The effects are confronted with the intercalation of nitrogen molecules (N2) and the equivalent adsorption of both species. The results show that the intercalation of NO2 can be energetically favorable for <0.4, 1.5–3.0, and >4.0 × 10^14 molecules/cm2 and that at low coverage, the molecule-sheet interactions are too weak to facilitate sufficient interlayer expansion, and thus the molecules dissociate. The dissociation and non-dissociative intercalation of NO2 enhance the per molecule charge transfer by 1110% and 256%, respectively, relative to adsorption. Hence, in all favorable cases, the intercalation should significantly enhance the response of the system. Furthermore, the results suggest that the evacuation of NO2 should be feasible, allowing MoTe2 recovery. In contrast, N2 intercalation is unfavorable, illustrating the selectivity of the process.
Box-Behnken Optimization and Theoretical Study for Copper Recovery from Scrap Laptop Computer Printed Circuit Board by Malonic Acid and Hydrogen Peroxide
Authors: Aderibigbe Abiodun , Olasupo Funbi , Odubola Deborah , Akintayo Temitope
Published: September 2022

Copper (Cu) is a major target in metal recovery during the recycling of scrap printed circuit boards (PCBs). Herein, we report on the optimization of parameters for the leaching of Cu from scrap PCB pieces by malonic acid and hydrogen peroxide (H2O2). Large PCBs obtained from scrap laptop computers were cut into smaller 2 cm by 2 cm pieces and de-epoxidized by NaOH treatment. The average Cu content in each PCB piece was determined by complete solubilization in aqua-regia and found to be (0.84±0.13) mg/g. An optimization study of three parameters including malonic acid concentration, H2O2 concentration, and contact time was carried out through the Box-Behnken design. Analysis of variance data revealed that the linear model was best fitted to the experimental data with R2 = 0.9591 and R2 (adjusted) = 0.8652, but the predictive power of the model was low with R2 (predicted) = 0.2298. The conditions at which the highest leaching efficiency of 51.3% was obtained were a malonic acid concentration of 0.5 M, a H2O2 concentration of 1.0 M, and a contact time of 75 min. The contact time was the most significant individual parameter that influenced the efficiency of Cu leached with a p-value of 0.001. Response surface plots revealed that high leaching efficiencies were observed at high malonic acid and H2O2 concentrations at prolonged contact time. Theoretical calculations show that the malonic acid prefers to coordinate with Cu in a 2:1 malonic acid: Cu ratio.
An Alternative Strategy for Spectral Tuning of Flavin-binding Fluorescent Proteins
Authors: Kabir Mohammad Pabel , Ouedraogo Daniel , Orozco-Gonzalez Yoelvis , Gadda Giovanni , Gozem Samer
Published: September 2022

iLOV is an engineered flavin-binding fluorescent protein (FbFP) with applications for in vivo cellular imaging. To expand the range of applications of FbFPs for multicolor imaging and FRET-based biosensing, it is desirable to understand how to modify their absorption and emission wavelengths (i.e., through spectral tuning). There is particular interest in developing FbFPs that absorb and emit light at longer wavelengths, which has proven challenging thus far. Existing spectral tuning strategies that do not involve chemical modification of the flavin cofactor have focused on placing positively charged amino acids near flavin’s C4a and N5 atoms. Guided by previously reported electrostatic spectral tunning maps (ESTMs) of the flavin cofactor and by quantum mechanical/molecular mechanical (QM/MM) calculations reported in this work, we suggest an alternative strategy: placing a negatively charged amino acid near flavin’s N1 atom. We predict that a single-point mutant, iLOV-Q430E, has a slightly red-shifted absorption and fluorescence maximum wavelength relative to iLOV. To validate our theoretical prediction, we experimentally expressed and purified iLOV-Q430E and measured its spectral properties. We found that the Q430E mutation in iLOV results in a slight change in absorption and a 4-8 nm redshift in the fluorescence relative to iLOV, in good agreement with the computational prediction. Molecular dynamics simulations showed that the carboxylate side chain of the glutamate in iLOV-Q430E points away from the flavin cofactor, which leads to a future expectation that further red-shifting may be achieved by bringing the side chain closer to the cofactor.
Valleytronic full configuration-interaction approach: An application to the excitation spectra of Si double-dot qubits
Authors: Yannouleas Constantine , Landman Uzi
Published: September 2022

A study of the influence of strong electron-electron interactions and Wigner-molecule (WM) formation on the spectra of 2e singlet-triplet double-dot Si qubits is presented based on a full configuration interaction (FCI) approach that incorporates the valley degree of freedom (VDOF) in the context of the continuous (effective mass) description of semiconductor materials. Our FCI solutions correspond to treating the VDOF as an isospin in addition to the regular spin. A major advantage of our treatment is its capability to assign to each energy curve in the qubit's spectrum a complete set of good quantum numbers for both the spin and the valley isospin. This allows for the interpretation of the Si double-dot spectra according to an underlying SU(4) ⊃ SU(2) × SU(2) group-chain organization. Considering parameters in the range of actual experimental situations, we demonstrate for the first time in a double-dot qubit that, in the (2,0) charge configuration and compared to the expected large, and dot-size determined, single-particle (orbital) energy gap, the strong e − e interactions drastically quench the spin-singlet−spin-triplet energy gap, E^⊕_ST, within the same valley, making it competitive to the small energy gap, E_V , between the two valleys. We present results for both the E^⊕_ST < E_V and E^⊕_ST > E_V cases, which have been reported to occur in different experimental qubit devices. In particular, we investigate the spectra as a function of detuning and demonstrate the strengthening of the all-important avoided crossings due to a lowering of the interdot barrier and/or the influence of valley-orbit coupling. We further demonstrate, as a function of an applied magnetic field, the emergence of avoided crossings in the (1,1) charge configuration due to the more general spin-valley coupling, in agreement with experiments. The valleytronic FCI method formulated and implemented in this paper, and demonstrated for the case of two electrons confined in a tunable double quantum dot, offers also a most effective tool for analyzing the spectra of Si qubits with more than two wells and/or more than two electrons, in field-free conditions, as well as under the influence of an applied magnetic field. Furthermore, it can also be straightforwardly extended to the case of bilayer graphene quantum dots.
Dispersion energy from the time-independent coupled-clusters polarization propagator
Authors: Zuchowski Piotr , Moszynski Robert
Published: September 2022

We present a new method of calculation of the dispersion energy in the second-order symmetry-adapted perturbation theory. Using the Longuet-Higgins integral and time-independent coupled-cluster response theory one shows that the general expression for the dispersion energy can be written in terms of cluster amplitudes and the excitation operators $\sigma$, which can be obtained by solving a linear equation. We introduced an approximate scheme dubbed CCPP2(T) for the dispersion energy accurate to the second order of intramonomer correlation, which includes certain classes to be summed to infinity. Assessment of the accuracy of the CCPP2(T) dispersion energy against the FCI dispersion for He$_2$ demonstrates its high accuracy. For more complex systems CCPP2(T) matches the accuracy of the best methods introduced for calculations of dispersion so far. The method can be extended to higher-order levels of excitations, providing a systematically improvable theory of dispersion interaction.
Engineering enzyme substrate scope complementarity for promiscuous cascade synthesis
Authors: McDonald Allwin D. , Bruffy Samantha K. , Kasat Aadhishre T. , Buller Andrew R.
Published: September 2022

Biocatalytic cascades are uniquely powerful for the efficient, asymmetric synthesis of bioactive compounds. The high specificity of enzymes can enable one-pot reactions where the substrates, intermediates, and products react only with the intended enzyme. However, this same specificity can hinder the substrate scope of biocatalytic cascades because each constituent enzyme requires complementary activity. Here, we implement a substrate multiplexed screening (SUMS) approach to improve the substrate scope overlap of a two-enzyme cascade via directed evolution. This cascade leverages an L-threonine transaldolase, ObiH, to produce a range of β-OH amino acids that are subsequently decarboxylated to produce chiral 1,2-amino alcohols. Crucially, for the success of this cascade, we engineered a tryptophan decarboxylase to act efficiently on β-OH amino acids while avoiding activity on L-threonine, which is needed for ObiH activity. We leverage this exquisite selectivity with matched substrate scopes to produce a variety of chiral 1,2-amino alcohols in a one-pot cascade from aldehydes or styrene oxides. This route constitutes a new disconnection for the synthesis of β-adrenergic receptor agonists and shows how SUMS can be used to guide the development of promiscuous, C-C bond forming cascades.
Control on dissipative kinetics reveals the entropically-dominated essence of interlocked molecular machines
Authors: Di Noja Simone , Garrido Marina , Gualandi Lorenzo , RAGAZZON GIULIO
Published: September 2022

The operation of nanomachines is fundamentally different from that of their macroscopic counterparts. In particular, the role of solvent is critical, yet rarely associated with machine functionality. Here we study a minimal model of one of the most advanced molecular machines, to gain control on its operation by engineering components and the employed solvent. Operation kinetics was modulated over more than four orders of magnitude, and could be fine-tuned. Leveraging solvent properties, it was possible to realize multiple cycles of the molecular machine operation while monitoring it. Our work expands the capabilities of acid-base powered molecular machines, contributing to the development of systems that leverage solvent properties to expand their functionality.