bluuebunny/crossref_metadata_2025 huggingface dataset:
Kajian In Vitro Kecernaan Fraksi Serat Hijauan Tropis pada Media Cairan Rumen Kambing
Authors: Hambakodu Marselinus , Kaka Alexander , Ina Yessy Tamu
Published: September 2020

ABSTRAKPenelitian ini bertujuan untuk mengevaluasi kecernaan NDF, kecernaan ADF dan kecernaan hemiselulosa pada hijauan pakan tropis secara in vitro. Materi yang digunakan dalam penelitian ini adalah 8 jenis pakan hijauan tropis dan cairan rumen kambing PE berfistula yang diberi pakan dengan kandungan PK 12% dan TDN 62%. Rancangan percobaan yang digunakan adalah rancangan acak lengkap 8 perlakuan pakan dan 3 ulangan. Perlakuan terdiri dari P1 = turi (Sesbania grandiflora), P2 = nangka (Artocarpus heterophyllus), P3 = pisang (Musa acuminate), P4 = mangga (Mangifera indica L.), P5 = gamal (Gliricidia sepium), P6 = mahoni (Swietenia mahagoni (L.) Jacq.), P7 = kaliandra (Calliandra calothyrsus) dan P8 = lamtoro (Leucaena leucocephala). Data dianalisis menggunakan ANOVA taraf 5%, dan dilanjutkan dengan uji Duncan. Hasil penelitian menunjukkan bahwa kecernaan NDF, kecernaan ADF, dan kecernaan hemiselulosa berbeda nyata (P<0,05). Hijauan pakan tropis lamtoro, kaliadra dan gamal memiliki kecernaan NDF, kecernaan ADF lebih tinggi dibandingkan turi, nangka, pisang, mangga, dan mahoni, namun kecernaan hemiselulosa kaliandra, manga dan lamtoro tertinggi. Kesimpulan, hijauan Leucaena leucocephala, Calliandra calothyrsus, dan Gliricidia sepium memiliki kecernaan NDF tertinggi (70,34%; 66,26% dan 62,29%), dan kecernaan ADF tertinggi (53,79%; 48,08%; dan 58,91%), namun kecernaan hemiselulosa tertinggi adalah Calliandra calothyrsus, Mangifera indica L, dan Leucaena leucocephala (18,18%; 17,80% dan 16,55%).Kata kunci: in vitro, hijauan tropis, kecernaan, serat ABSTRACTThis research was conducted to evaluate neutral detergent fiber digestibility, acid detergent fiber digestibility, and hemicellulose digestibility on tropical browse plants in vitro. The materials used in this research were 8 types of tropical forages and rumen fluid from Etawa Crossbreed goat fistulated with CP 12 % and 62 % TDN. The experimental design used was the completely randomized design of 8 feed treatments and 3 replications. Treatments consisted of P1 = Sesbania grandiflora, P2 = Artocarpus heterophyllus, P3 = Musa acuminata, P4 = Mangifera indica L., P5 = Gliricidia sepium, P6 = Swietenia mahagoni (L.) Jacq, P7 = Calliandra calothyrsus, and P8 = Leucaena leucocephala. Data were analyzed using ANOVA 5%, and continued by Duncan test. The results of the study showed that neutral detergent fiber digestibility, acid detergent fiber digestibility, hemicellulose digestibility were significantly (P<0.05). Tropical forages of Leucaena leucocephala and Gliricidia sepium were highest neutral detergent fiber digestibility (70,34% and 62,29%), and highest acid detergent fiber digestibility (57,14% and 58,91%), with hemicellulose digestibility (64,10% and 65,00%).Keywords: digestibility, fiber, tropical browse plants, in vitro
Aplikasi Pupuk Kompos Isi Rumen dalam Meningkatkan Produktivitas Rumput Gajah di Lahan Marginal
Authors: Hidayati Nurul , Agustina Desi Kurniati
Published: September 2020

ABSTRAKPupuk kompos isi rumen sapi masih belum banyak digunakan dalam pertanian utamanya penanaman Rumput gajah di lahan marginal. Oleh karena itu, penelitian ini bertujuan untuk mengetahui pengaruh pemberian pupuk kompos isi rumen terhadap pertumbuhan dan produksi rumput gajah di lahan marginal.  Penelitian ini merupakan penelitian eksperimen menggunakan Rancangan Acak Kelompok (RAK) dengan 6 perlakuan dan 3 ulangan. Perlakuan yang diberikan yaitu, P0: rumput gajah tanpa pemupukan, P1: rumput gajah diberikan pupuk NPK 500 kg/ha, P2: rumput gajah diberikan pupuk kompos isi rumen 1000 kg/ha, P3-P5 berturut-turut : rumput gajah diberikan pupuk NPK 500 kg/ha dan  pupuk kompos isi rumen 500 kg/ha, 750 kg/ha, dan 1000 kg/ha. Pengamatan dilakukan pada pertumbuhan, produksi, serta kandungan kimia Rumput gajah. Berdasarkan hasil penelitian pemberian pupuk kompos isi rumen sapi dapat meningkatkan pertumbuhan rumput gajah yaitu pada tinggi tanaman, jumlah daun dan lebar daun pada pengamatan minggu ke 5 dan ke 6, P<0.05. Rumput gajah yang diberi Perlakuan pupuk anorganik dan pupuk kompos Isi rumen (P3-P5) memiliki produksi lebih tinggi dibandingkan P1 dan P2. Kandungan serat kasar, protein kasar, N, P, dan K dan jumlah bakteri pada perakaran lebih tinggi pada rumput gajah yang diberi pupuk anorganik NPK dan pupuk kompos isi rumen.Kata kunci: isi rumen sapi, lahan marginal, pupuk kompos, rumput gajahABSTRACTThe compost fertilizer of cow’s rumen contains is still not widely used in agriculture yet, mainly the planting of elephant grass on marginal land. Therefore, the purpose of this study was to determine the effect of rumen content compost fertilizer on the growth and production of elephant grass in marginal land. This study used an experimental method using a randomized block design (RBD) with 6 treatments and 3 replications. The treatments given are, P0: elephant grass without fertilization, P1: elephant grass with NPK fertilizer 500kg/ha, P2: elephant grass with compost rumen content of 1000kg/ha, P3-P5 successively: Elephant grass with NPK fertilizer 500kg/ha and 500kg/ha, 750kg/ha, and 1000kg/ha of rumen compost fertilizer. Observations were made on the growth, production, and chemical content of elephant grass. The results of research, compost rumen content can increase the growth of elephant grass, namely on plant height, the number of leaves and leaf width at the 5th and 6th week of observation, P<0.05. Elephant grass treated with inorganic fertilizer and compost rumen content (P3-P5) has higher production than P1 and P2. The content of crude fiber, crude protein, NPK and number of bacteria in roots is higher in Elephant Grass which is given inorganic fertilizer and compost rumen fertilizer.Keywords: compost fertilizer, elephant grass, marginal land
The Effect of algan hemostatic agent (AHA) on wound healing
Authors: AKSOY Halil , SENER Azize , AKAKIN Dilek , ŞEN Ali , BİNGÖL AKPINAR Özlem , ÖZCAN Gül Sinemcan , ŞİMŞEK Ahmet Kaan , ŞEKERLER Turgut , GÜZEL Şevket Ergun , MİDİ Ahmet
Published: September 2020

Objective: The Algan Hemostatic Agent (AHA) is a novel herbal originated blood stopper. The aim of this study is to investigate the effect of AHA on wound healing on excisional wound model in rats.

Methods: In this study, 54 adult Wistar albino rats were used. Rats were divided into 3 groups (saline, Madecassol and AHA). Each group was then divided into 3 subgroups as 3rd, 7th and 14th days. Two wounds were created in the dorsal thoracic region of the rats. One of the lesions was used for histopathological examinations and the other for hydroxyproline measurement. In order to evaluate the wound healing, wound area were measured during the whole treatment period and animals were sacrificed at the end of 3rd, 7th and 14th days and tissue samples were taken for the determination of hydroxyproline levels.

Results: AHA treatment did not cause significantly difference in hydroxyproline level on days 3, 7, 14. The contraction percentage of wound area was higher in the AHA group on day 7 than control group. However, the difference was not statistically significant (p> 0.05). On days 3 and 14, no significant difference was detected in the contraction percentage of wound area between the control and AHA groups. AHA and Madecassol results of epidermis regeneration on the 14th day, neutrophil infiltration on the 7th day and edema on the 3rd, 7th and 14th days were different in terms of histopathological parameters compared to the control group.

Conclusion: Despite good histological findings, AHA did not significantly accelerate wound healing. but did not adversely affect on wound healing. AHA may be used safely on excisional wounds.
HUBUNGAN LAMA PENGGUNAAN INTRAUTERINE DEVICE DENGAN KADAR HEMOGLOBIN PADA AKSEPTOR KB IUD DI WILAYAH KERJA PUSKESMAS BANGKO TAHUN 2020
Authors: Revinovita Revinovita
Published: September 2020

Latar belakang : Menurut World Population Data Sheet 2016, Indonesia merupakan negara ke 4 di dunia dengan estimasi jumlah penduduk terbanyak. Salah satu program Pemerintah untuk mengantisipasi laju pertumbuhan penduduk di Indonesia adalah Metode Kontrasepsi Jangka Panjang (MKJP) yaitu Intrauterine Devices (IUD). Angka efektivitas yang tinggi antara 70% dan 90% setelah 1 tahun penggunaan. Efek samping yang sering timbul karena pemakaian AKDR dengan atau tanpa obat adalah peningkatan volume darah haid per siklus.Metode : Penelitian ini merupakan penelitian analitik dengan rancangan cross sectional.Tujuan Penelitian ini adalah untuk mengetahui hubungan lama penggunaan AKDR dengan kadar hemoglobin pada akseptor KB di wilayah kerja Puskesmas Bangko tahun 2020 dengan sampel 59 dari 117 akseptor IUD.Hasil : Berdasarkan hasil penelitian didapatkan dari 59 responden yang diteliti, 44 wanita PUS pengguna IUD pemakaian jangka panjang, terdapat sebanyak 32 (72,7%) responden yang anemia dan sebanyak 12 (27,3%) responden yang tidak anemia. Sedangkan dari 15 wanita PUS pengguna IUD pemakaian jangka pendek terdapat 5 (33,3%) responden yang anemia dan sebanyak 10 (66,7%) responden yang tidak anemia. Hasil analisis uji Chi Square diketahui nilai X2 hitung X2 tabel yaitu 7,397 3,841.Kesimpulan : Ada hubungan yang bermakna antara lama penggunaan IUD dengan kadar Hb pada akseptor KB IUD di wilayah kerja Puskesmas Bangko Tahun 2020. Diharapkan tenaga kesehatan melakukan pengecekan Hb pada awal pemasangan IUD dan pada saat kunjungan ulang akseptor serta memberikan tablet Fe pada akseptor Kb IUD jangka panjangKata kunci : Lama Penggunaan IUD, Kadar Haemoglobin.
From Old-Generation to Next-Generation Nematicides
Authors: Oka Yuji
Published: September 2020

The phaseout of methyl bromide and the ban on, or withdrawal of, other toxic soil fumigants and non-fumigant nematicides belonging to the organophosphate and carbamate groups are leading to changes in nematode-control strategies. Sustainable nematode-control methods are available and preferred, but not always effective enough, especially for cash crops in intensive agriculture. A few non-fumigant nematicides, which have a relatively high control efficacy with a low toxicity to non-target organisms, have been released to the market or are in the process of being registered for use. Fluensulfone, fluopyram, and fluazaindolizine are the three main and most promising next-generation nematicides. In this paper, several aspects of these non-fumigant nematicides are reviewed, along with a brief history and problems of old-generation nematicides.
Oxidative Stress and Inflammatory Modulation of Ca2+ Handling in Metabolic HFpEF-Related Left Atrial Cardiomyopathy
Authors: Bode David , Wen Yan , Hegemann Niklas , Primessnig Uwe , Parwani Abdul , Boldt Leif-Hendrik , M. Pieske Burkert , R. Heinzel Frank , Hohendanner Felix
Published: September 2020

Metabolic syndrome-mediated heart failure with preserved ejection fraction (HFpEF) is commonly accompanied by left atrial (LA) cardiomyopathy, significantly affecting morbidity and mortality. We evaluate the role of reactive oxygen species (ROS) and intrinsic inflammation (TNF-α, IL-10) related to dysfunctional Ca2+ homeostasis of LA cardiomyocytes in a rat model of metabolic HFpEF. ZFS-1 obese rats showed features of HFpEF and atrial cardiomyopathy in vivo: increased left ventricular (LV) mass, E/e’ and LA size and preserved LV ejection fraction. In vitro, LA cardiomyocytes exhibited more mitochondrial-fission (MitoTracker) and ROS-production (H2DCF). In wildtype (WT), pro-inflammatory TNF-α impaired cellular Ca2+ homeostasis, while anti-inflammatory IL-10 had no notable effect (confocal microscopy; Fluo-4). In HFpEF, TNF-α had no effect on Ca2+ homeostasis associated with decreased TNF-α receptor expression (western blot). In addition, IL-10 substantially improved Ca2+ release and reuptake, while IL-10 receptor-1 expression was unaltered. Oxidative stress in metabolic syndrome mediated LA cardiomyopathy was increased and anti-inflammatory treatment positively affected dysfunctional Ca2+ homeostasis. Our data indicates, that patients with HFpEF-related LA dysfunction might profit from IL-10 targeted therapy, which should be further explored in preclinical trials.
Effect of Urea-Formaldehyde (UF) with Waterborne Emulsion Microcapsules on Properties of Waterborne Acrylic Coatings Based on Coating Process for American Lime
Authors: Yan Xiaoxing , Zhao Wenting , Qian Xingyu
Published: September 2020

The purpose of this paper is to explore the effect of urea-formaldehyde (UF) with waterborne emulsion microcapsules on the optical, mechanical and aging resistance properties of waterborne coatings from the perspective of coating process. In this paper, the microcapsules were prepared with UF resin as the wall materials and waterborne emulsion as the core materials. Based on the coating process, the optical, mechanical and aging resistance properties of the waterborne acrylic coatings with microcapsules for American lime were tested. The good coating process is three layers of primer, two layers of topcoat, and adding microcapsules into primer. The results showed that the coating process had little effect on the color difference of the paint film with microcapsules, the gloss of the paint film prepared by the good coating process was basically not changed, and the mechanical properties of the paint film were good. At this time, the hardness grade of the paint film was 3H, the adhesion was grade 0, the impact resistance was 110.0 N·cm−2, and the elongation at break was 29.7%. The microcapsules added to the primer had better liquid resistance than those added to the topcoat. The paint film had good stability and aging resistance, and could inhibit the generation of microcracks to a certain extent. The paint film prepared by the good coating process had better comprehensive performance. This work provides a technical reference for self-healing of the waterborne coatings on American lime.
Evaluating the Cost Efficiency of Systems Engineering in Oil and Gas Projects
Authors: Glukhikh Igor Nikolaevich , Mozhchil Artyom Fedorovich , Pisarev Mikhail Olegovich , Arzykulov Otabek Anzor ugli , Nonieva Kristina Zakharovna
Published: September 2020

Studies of systems engineering applications have revealed that systems engineering (SE) has a high potential for transferring economically inefficient oil and gas projects into a profitable zone due to preserving the value created at the concept stage right up to the implementation stage. To implement any project, including an organizational one, the company must have an economic justification for innovation. Studies into the global experience of assessing SE efficiency based on projects of various types have revealed the lack of a universal assessment method; however, individual studies have potential to be used in developing a method for quantifying the value of SE in oil and gas projects. Considering this fact, we developed our own method and prototype to assess the economic effect from the introduction of SE into oil and gas projects. The method is based on a decision tree used to calculate the Net Present Value considering the probability of projects’ success and failure in terms of budget and deadlines. This allowed us to predict the effect from introducing SE to an oil company’s capital project. The results obtained demonstrated the model’s performance capability and its possible applications in project resource planning stages.
Effects of Experimental Agents Containing Tannic Acid or Chitosan on the Bacterial Biofilm Formation in Situ
Authors: Schestakow Anton , Hannig Matthias
Published: September 2020

Chitosan and tannic acid are known for their antibacterial properties. In the present in-situ study, their antibacterial and anti-adherent effects on biofilm formation on enamel were investigated. Six subjects carried upper jaw splints with bovine enamel specimens, allowing in-situ biofilm formation. During the two-day trial, subjects rinsed with experimental solutions that contained either chitosan, tannic acid (pH = 2.5), tannic acid (pH = 7) or hydrochloric acid. Water served as the negative and chlorhexidine as the positive control. Rinsing occurred four or five times following two different rinsing protocols to investigate both the immediate and long-lasting effects. After 48 h of intraoral exposure, the dental plaque was stained with LIVE/DEAD® BacLight, and fluorescence micrographs were evaluated by using the software ImageJ. The results were verified by scanning electron microscopy. Rinsing with chitosan resulted in little immediate antibacterial and anti-adherent effects but failed to show any long-lasting effect, while rinsing with tannic acid resulted in strong immediate and long-lasting effects. Except for a slightly lower antibacterial effect, the neutral solution of tannic acid was as good as the acidic solution. Hydrochloric acid showed neither an antibacterial nor an anti-adherent effect on dental biofilm formation. Experimental solutions containing tannic acid are promising anti-biofilm agents, irrespective of the pH values of the solutions. Chitosan, on the other hand, was not able to prevent biofilm formation.
Anti-Corrosive Coating of Carbon-Steel Assisted by Polymer-Camphorsulfonic Acid Embedded within Graphene
Authors: Zhai Yingying , Pan Kefeng , Zhang Ende
Published: September 2020

A novel, economic and environmentally friendly anticorrosion coating material for metals is introduced and investigated in this paper. For this purpose, camphor-sulfonic-acid/graphene-doped poly(o-toluidine) composites (MG/CSA@POT) were fabricated using in-situ polymerization with (NH4)2S2O8 as an oxidant. The structure and the morphology of MG/CSA@POT were analyzed using FTIR (Fourier-transform infrared spectroscopy), XRD (X-ray diffraction), and SEM (Scanning Electron Microscope). Multilayer graphene (MG)/CSA@POT-polyurethane composite coatings (MG/CSA@POT-WPU) were prepared on the surface of a carbon steel substrate by mixing MG/CSA@POT with waterborne polyurethane via blending. The corrosion performance of the MG/CSA@POT-WPU composite coatings in a 3.5% NaCl solution was studied with a corrosion electrochemical method. The results showed that 5-MG/CSA@POT-WPU had the best shielding effect on corrosive media and the lowest corrosion rate (1.02 × 10−6 mm/year) compared to other coatings while its inhibition efficiency reached 99.96%.
The Siegel–Klein Disk: Hilbert Geometry of the Siegel Disk Domain
Authors: Nielsen Frank
Published: September 2020

We study the Hilbert geometry induced by the Siegel disk domain, an open-bounded convex set of complex square matrices of operator norm strictly less than one. This Hilbert geometry yields a generalization of the Klein disk model of hyperbolic geometry, henceforth called the Siegel–Klein disk model to differentiate it from the classical Siegel upper plane and disk domains. In the Siegel–Klein disk, geodesics are by construction always unique and Euclidean straight, allowing one to design efficient geometric algorithms and data structures from computational geometry. For example, we show how to approximate the smallest enclosing ball of a set of complex square matrices in the Siegel disk domains: We compare two generalizations of the iterative core-set algorithm of Badoiu and Clarkson (BC) in the Siegel–Poincaré disk and in the Siegel–Klein disk: We demonstrate that geometric computing in the Siegel–Klein disk allows one (i) to bypass the time-costly recentering operations to the disk origin required at each iteration of the BC algorithm in the Siegel–Poincaré disk model, and (ii) to approximate fast and numerically the Siegel–Klein distance with guaranteed lower and upper bounds derived from nested Hilbert geometries.
The Concept, Technical System and Heat Transfer Analysis on Phase-Change Heat Storage Backfill for Exploitation of Geothermal Energy
Authors: Zhang Xiaoyan , Xu Muyan , Liu Li , Liu Lang , Wang Mei , Ji Haiwei , Song KI-IL
Published: September 2020

In view of high ground stress, high geothermal temperature, and thermal hazard during deep mineral resource exploitation, the concept of phase-change heat storage backfill was put forward in this study. Further, the corresponding technical system was constructed and the main content involved in technical system, which is the optimized proportion of the backfill slurry added with phase-change materials (PCMs), was examined. Moreover, we elaborated upon the collaborative optimization of a backfill body’s mechanical and thermal properties and the mutual cooperation on backfill mining, geothermal energy exploitation, and simultaneous stope cooling. The heat transfer behavior of a backfill body plays a key role in technology system. We numerically simulated the heat transfer among a backfill body, surrounding rock, and airflow in the heat storage process, as well as the heat transfer between backfill body and cold fluid during the heat release process. The temperature distribution of a backfill body at different heat storage/heat release times—i.e., the temperature distribution and its evolution—with heat transfer were revealed and analyzed. This study can provide theoretical guidance for a phase-change heat storage backfill, as it has an important significance for the collaborative exploitation of mineral resources and geothermal energy.
Investigation of Waste Biogas Flame Stability Under Oxygen or Hydrogen-Enriched Conditions
Authors: Striūgas Nerijus , Paulauskas Rolandas , Skvorčinskienė Raminta , Lisauskas Aurimas
Published: September 2020

Increasing production rates of the biomethane lead to increased generation of waste biogases. These gases should be utilized on-site to avoid pollutant emissions to the atmosphere. This study presents a flexible swirl burner (~100 kW) with an adiabatic chamber capable of burning unstable composition waste biogases. The main combustion parameters and chemiluminescence emission spectrums were examined by burning waste biogases containing from 5 to 30 vol% of CH4 in CO2 under air, O2-enriched atmosphere, or with the addition of hydrogen. The tested burner ensured stable combustion of waste biogases with CH4 content not less than 20 vol%. The addition of up to 5 vol% of H2 expanded flammability limits, and stable combustion of the mixtures with CH4 content of 15 vol% was achieved. The burner flexibility to work under O2-enriched air conditions showed more promising results, and the flammability limit was expanded up to 5 vol% of CH4 in CO2. However, the combustion under O2-enriched conditions led to increased NOx emissions (up to 1100 ppm). Besides, based on chemiluminescence emission spectrums, a linear correlation between the spectral intensity ratio of OH* and CH* (IOH*/ICH*) and CH4 content in CO2 was presented, which predicts blow-off limits burning waste biogases under different H2 or O2 enrichments.
Comparison between Hydrogen and Syngas Fuels in an Integrated Micro Gas Turbine/Solar Field with Storage
Authors: Cameretti Maria Cristina , Cappiello Alessandro , De Robbio Roberta , Tuccillo Raffaele
Published: September 2020

In recent years, the use of alternative fuels in thermal engine power plants has gained more and more attention, becoming of paramount importance to overcome the use of fuels from fossil sources and to reduce polluting emissions. The present work deals with the analysis of the response to two different gas fuels—i.e., hydrogen and a syngas from agriculture product—of a 30 kW micro gas turbine integrated with a solar field. The solar field included a thermal storage system to partially cover loading requests during night hours, reducing fuel demand. Additionally, a Heat Recovery Unit was included in the plant considered and the whole plant was simulated by Thermoflex® code. Thermodynamics analysis was performed on hour-to-hour basis, for a given day as well as for 12 months; subsequently, an evaluation of cogeneration efficiency as well as energy saving was made. The results are compared against plant performance achieved with conventional natural gas fueling. After analyzing the performance of the plant through a thermodynamic analysis, the study was complemented with CFD simulations of the combustor, to evaluate the combustion development and pollutant emissions formation, particularly of NOx, with the two fuels considered using Ansys-Fluent code, and a comparison was made.
A Simple Method to Validate Power Loss in Medium Voltage SiC MOSFETs and Schottky Diodes Operating in a Three-Phase Inverter
Authors: Rąbkowski Jacek , Skoneczny Hubert , Kopacz Rafał , Trochimiuk Przemysław , Wrona Grzegorz
Published: September 2020

This paper presents an original method of power loss validation in medium-voltage SiC MOSFET (metal–oxide–semiconductor field-effect transistor) modules of a three-phase inverter. The base of this method is a correct description of the on-state performance of the diodes and the transistors in a PWM (pulse width modulation)-controlled inverter phase leg. Combined electro-thermal calculations are applied to precisely estimate the losses in the power devices and then, to find the suitable circuit parameters of a test circuit to emulate these conditions. A simple square-wave-controlled half-bridge with an inductive load enables the electrical and thermal stresses comparable to these in the inverter, and moreover, provided equations that confirmed the possibility of balancing the load between the diodes and the transistors. The circuit with 3.3 kV SiC MOSFETs was tested to verify the impact of selected parameters on power losses with the main focus on duty ratio. The same module was applied, in addition to an inductive load (3 × 112 μH) and two sets of DC-link capacitors (750 μF), to validate a phase leg of a 220 kVA inverter. In spite of a significantly apparent power, the active power delivered from the DC supply settled around 1 kW, which was enough to emulate 390 W of losses in two transistors and diodes.
An Intelligent Automatic Adaptive Maximum Power Point Tracker for Photovoltaic Module Arrays
Authors: Chao Kuei-Hsiang , Lai Yu-Ju
Published: September 2020

In this study, a maximum power point tracker was developed for photovoltaic module arrays by using a teacher-learning-based optimization (TLBO) algorithm to control the photovoltaic system. When a photovoltaic module array is shaded, a conventional maximum power point tracker may obtain the local maximum power point rather than the global maximum power point. The tracker developed in this study was aimed at solving this problem. To prove the viability of the proposed method, a SANYO HIP 2717 photovoltaic module with diverse connection patterns and shading ratios was used. Thus, single-peak, double-peak, triple-peak, and multi-peak power–voltage characteristic curves of the photovoltaic module array were obtained. A simulation of maximum power point tracking (MPPT) was then performed with MATLAB software. With regard to practical testing, a boost converter was used as the hardware structure of the maximum power point tracker and a TMS320F2808 digital signal processor was selected to execute the rules for MPPT. The results of the practical tests verified that the proposed improved TLBO algorithm had a superior accuracy to existing TLBO algorithms. In addition, the proposed improved TLBO algorithm can shorten the tracking time to 1/2 or 1/4, so it can improve the efficiency of power generation by two to three percentage.
Multi-Agent Cooperation Based Reduced-Dimension Q(λ) Learning for Optimal Carbon-Energy Combined-Flow
Authors: Cao Huazhen , Gao Chong , He Xuan , Li Yang , Yu Tao
Published: September 2020

This paper builds an optimal carbon-energy combined-flow (OCECF) model to optimize the carbon emission and energy losses of power grids simultaneously. A novel multi-agent cooperative reduced-dimension Q(λ) (MCR-Q(λ)) is proposed for solving the model. Firstly, on the basis of the traditional single-objective Q(λ) algorithm, the solution space is reduced effectively to shrink the size of Q-value matrices. Then, based on the concept of ant cooperative cooperation, multi-agents are used to update the Q-value matrices iteratively, which can significantly improve the updating rate. The simulation in the IEEE 118-bus system indicates that the proposed technique can decrease the convergence speed by hundreds of times as compared with conventional Q(λ), keeping high global stability, which is very suitable for dynamic OCECF in a large and complex power grid compared with other algorithms.
NZEB Analyses by Means of Dynamic Simulation and Experimental Monitoring in Mediterranean Climate
Authors: Magrini Anna , Lentini Giorgia
Published: September 2020

The reduction of energy consumption in the building sector has promoted the spread of the NZEB (Nearly Zero Energy Building) model. A future target is represented by positive-energy buildings (PEB), which produce more energy than they consume. The study is centred on the examination of some peculiarities of NZEB through a case study and on the analysis of opportunities for further increase in energy performance, to trace the road that each designer should take, through an extensive evaluation of the potentials variations on the project that could lead to better results. The project assessments are developed through a dynamic simulation model and the data from the monitoring of the building’s performance are used to evaluate the actual energy saving conditions. The analyses demonstrate the importance of an accurate design of the envelope and technical building systems associated with a smart management of the control systems and the setting of the set points, for the optimal operation of the systems. Ambitious but feasible design choices and an accurate analysis of the possibility of increasing the energy performance of a NZEB can lead to reaching the PEB target and energy independence, enhancing the production of energy from renewable sources.
An Artificial Neural Network for the Low-Cost Prediction of Soot Emissions
Authors: Jadidi Mehdi , Kostic Stevan , Zimmer Leonardo , Dworkin Seth B.
Published: September 2020

Soot formation in combustion systems is a growing concern due to its adverse environmental and health effects. It is considered to be a tremendously complicated phenomenon which includes multiphase flow, thermodynamics, heat transfer, chemical kinetics, and particle dynamics. Although various numerical approaches have been developed for the detailed modeling of soot evolution, most industrial device simulations neglect or rudimentarily approximate soot formation due to its high computational cost. Developing accurate, easy to use, and computationally inexpensive numerical techniques to predict or estimate soot concentrations is a major objective of the combustion industry. In the present study, a supervised Artificial Neural Network (ANN) technique is applied to predict the soot concentration fields in ethylene/air laminar diffusion flames accurately with a low computational cost. To gather validated data, eight different flames with various equivalence ratios, inlet velocities, and burner geometries are modeled using the CoFlame code (a computational fluid dynamics (CFD) parallel combustion and soot model) and the Lagrangian histories of soot-containing fluid parcels are computed and stored. Then, an ANN model is developed and optimized using the Levenberg-Marquardt approach. Two different scenarios are introduced to validate the network performance; testing the prediction capabilities of the network for the same eight flames that are used to train the network, and for two new flames that are not within the training data set. It is shown that for both of these cases the ANN is able to predict the overall soot concentration field very well with a relatively low integrated error.
Real Drive Well-to-Wheel Energy Analysis of Conventional and Electrified Car Powertrains
Authors: Orecchini Fabio , Santiangeli Adriano , Zuccari Fabrizio
Published: September 2020

Reducing fuel consumption and global emissions in the automotive sector has been a main focus of vehicle technology development for long time. The most effective goal to achieve the overall sustainability objectives is to reduce the need for non-renewable and fossil resources. Five vehicles, two conventional ICE, two hybrid-electric, and one pure electric powertrain, are considered. Non-renewable primary energy consumption and CO2 emissions are calculated for each powertrain considered. All data—including calculated values—are based on the experimental measure of fuel consumption taken in real driving conditions. The data were recorded in an experimental campaign in Rome, Italy on urban, extra-urban streets, and highway on a total of 5400 km and 197 h of road acquisitions. The analysis shows significant reductions in non-renewable fossil fuel consumption and CO2 emissions of hybrid-electric powertrains compared to conventional ones (petrol and diesel engines). Furthermore, a supplementary and very interesting comparison analysis was made between the values of energy consumptions measured during the tests in real driving conditions and the values deriving from the NEDC and WLTP homologation cycles.
A Novel Cascaded Multilevel Converter Topology Based on Three-Phase Cells—CHB-SDC
Authors: Camargo Renner Sartório , Mayor Daniel Santamargarita , Miguel Alvar Mayor , Bueno Emilio José , Encarnação Lucas Frizera
Published: September 2020

This paper proposes a new cascaded multilevel converter topology based on three-phase H bridge cells with a common DC-link structure. The proposed multilevel converter topology main advantages, compared with literature renowned multilevel converters topologies, are discussed in the paper, such as modularity, construction, implementation cost, and DC voltage ripple mitigation. Despite presenting an elementary structure and easy implementation, the use of classic PWM switching strategies is not feasible for this topology, causing the appearance of several short-circuit states between its capacitors. Thus, a graph theory algorithm combined with a model predictive control is also proposed in this work to identify and avoid the new cascaded multilevel converter short-circuit switching states and, concomitantly, guaranteeing the converter output power quality. In order to validate the presented topology applicability, a low voltage synchronous static compensators (STATCOM) with an optimal switching vector model predictive control (OSV-MPC) is implemented in a hardware-in-the-loop platform. The real-time experimental results prove the proposed multilevel topology and the OSV-MPC control strategy effectiveness.
Proof-of-Concept of High-Pressure Torrefaction for Improvement of Pelletized Biomass Fuel Properties and Process Cost Reduction
Authors: Matyjewicz Bartosz , Świechowski Kacper , Koziel Jacek A. , Białowiec Andrzej
Published: September 2020

This paper provides a comprehensive description of the new approach to biomass torrefaction under high-pressure conditions. A new type of laboratory-scale high-pressure reactor was designed and built. The aim of the study was to compare the high-pressure torrefaction with conventional near atmospheric pressure torrefaction. Specifically, we investigated the torrefaction process influence on the fuel properties of wooden-pellet for two different pressure regimes up to 15 bar. All torrefaction processes were conducted at 300 °C, at 30 min of residence time. The initial analysis of the increased pressure impact on the torrefaction parameters: mass yields, energy densification ratio, energy yield, process energy consumption, the proximate analysis, high heating value, and energy needed to grind torrefied pellets was completed. The results show that high-pressure torrefaction needed up to six percent less energy, whereas energy densification in the pellet was ~12% higher compared to conventional torrefaction. The presence of pressure during torrefaction did not have an impact on the energy required for pellet grinding (p < 0.05).
Unidirectional DC/DC Converter with Voltage Inverter for Fast Charging of Electric Vehicle Batteries
Authors: Szymanski Jerzy Ryszard , Zurek-Mortka Marta , Wojciechowski Daniel , Poliakov Nikolai
Published: September 2020

The paper proposes the adaptation of the industrial plant’s power network to supply electric vehicle (EV) fast-charging converters (above 300 kW) using renewable energy sources (RESs). A 600 V DC microgrid was used to supply energy from RESs for the needs of variable speed motor drives and charging of EV batteries. It has been shown that it is possible to support the supply of drive voltage frequency converters (VFCs) and charging of EV batteries converters with renewable energy from a 600 V DC microgrid, which improves the power quality indicators in the power system. The possibility of implementing the fast EV batteries charging station to the industrial plant’s power system in such a way that the system energy demand is not increased has also been shown. The EV battery charging station using the drive converter has been presented, as well as the results of simulation and laboratory tests of the proposed solution.
Comparing Hydrogen Sulfide Removal Efficiency in a Field-Scale Digester Using Microaeration and Iron Filters
Authors: Huertas Joanna K. , Quipuzco Lawrence , Hassanein Amro , Lansing Stephanie
Published: September 2020

Biological desulfurization of biogas from a field-scale anaerobic digester in Peru was tested using air injection (microaeration) in separate duplicate vessels and chemical desulfurization using duplicate iron filters to compare hydrogen sulfide (H2S) reduction, feasibility, and cost. Microaeration was tested after biogas retention times of 2 and 4 h after a single injection of ambient air at 2 L/min. The microaeration vessels contained digester sludge to seed sulfur-oxidizing bacteria and facilitate H2S removal. The average H2S removal efficiency using iron filters was 32.91%, with a maximum of 70.21%. The average H2S removal efficiency by iron filters was significantly lower than microaeration after 2 and 4 h retention times (91.5% and 99.8%, respectively). The longer retention time (4 h) resulted in a higher average removal efficiency (99.8%) compared to 2 h (91.5%). The sulfur concentration in the microaeration treatment vessel was 493% higher after 50 days of treatments, indicating that the bacterial community present in the liquid phase of the vessels effectively sequestered the sulfur compounds from the biogas. The H2S removal cost for microaeration (2 h: $29/m3 H2S removed; and 4 h: $27/m3 H2S removed) was an order of magnitude lower than for the iron filter ($382/m3 H2S removed). In the small-scale anaerobic digestion system in Peru, microaeration was more efficient and cost effective for desulfurizing the biogas than the use of iron filters.
Study on the Influencing Factors of the Emulsion Stability of a Polymeric Surfactant Based on a New Emulsification Device
Authors: Wei Yusen , Xiong Youming , Guo Bumin , Yang Hongbin
Published: September 2020

Polymeric surfactant flooding is an effective method to improve oil recovery, and the stability of the emulsion is closely related to the effect of surfactant flooding. The preparation method for a surfactant-stabilized emulsion is relatively simple, and the emulsion produced by the existing device cannot simulate the real formation conditions. To better simulate the emulsification of polymeric surfactant during formation and to study the influencing factors of emulsion stability, a new sieve plate rotary emulsification device was used to prepare emulsions instead of the traditional high-speed shear emulsifier, and the stability of emulsions prepared by different methods was compared. The parameters of the device were optimized by determining the water content, particle size, and Turbiscan Stability Index TSI (stability parameter) of the emulsion. The factors affecting the stability of the emulsion were studied by using the optimized experimental device. The results showed that the optimized parameters of the sieve plate rotary emulsification device were 5 sieve plates, diameter of 1 mm, and emulsification time of 60 min. The stability of the emulsion prepared by the new device was better than that of the emulsion prepared by the traditional high-speed stirrer, which can be attributed to the more abundant contact and mix of oil and surfactant solution. Meanwhile, as the polymeric surfactant concentration, salinity, and water–oil ratio increased, the stability of the polymeric surfactant emulsion increased. The results of this study provide a theoretical basis and guidance for better simulation of polymeric surfactant migration and emulsification during formation.
A Local Protection and Local Action Strategy of DC Grid Fault Protection
Authors: Yu Jingqiu , Zhang Zheren , Xu Zheng
Published: September 2020

Fast detection and isolation of direct current (DC) faults are key issues for DC grids. Therefore, it is very necessary to study the fault protection principle for DC grids. This paper firstly presents the main difficulties in DC fault protection. Then, a local protection and local action strategy for isolating the DC faults is proposed. To illustrate the performance of the proposed protection strategy, a four-terminal DC grid with the hybrid high voltage direct current (HVDC) circuit breakers (HVDC CBs) is constructed in the time-domain simulation software PSCAD/EMTDC as the test system. The systematical comparison between the ordinary protection strategy and the proposed strategy is carried out. The protection selectivity of the proposed local detection and local action strategy is thoroughly studied through complete DC line fault scanning of the test system. The simulation results show that the proposed strategy is of high protection selectivity and speed. In addition, the current rating and the voltage of HVDC CB could be greatly reduced with the proposed strategy, which proves the economic benefits of the proposed strategy.
Optimization Model for the Long-Term Operation of an Interprovincial Hydropower Plant Incorporating Peak Shaving Demands
Authors: Cao Rui , Shen Jianjian , Cheng Chuntian , Wang Jian
Published: September 2020

The increasing peak-to-valley load difference in China pose a challenge to long-distance and large-capacity hydropower transmission via high-voltage direct current (HVDC) lines. Considering the peak shaving demands of load centers, an optimization model that maximizes the expected power generation revenue is proposed here for the long-term operation of an interprovincial hydropower plant. A simulation-based method was utilized to explore the relationships between long-term power generation and short-term peak shaving revenue in the model. This method generated representative daily load scenarios via cluster analysis and approximated the real-time electricity price of each load profile with the time-of-use price strategy. A mixed-integer linear programming model with HVDC transmission constraints was then established to obtain moving average (MA) price curves that bridged two time-coupled operations. The MA price curves were finally incorporated into the long-term optimization model to determine monthly generation schedules, and the inflow uncertainty was addressed by discretized inflow scenarios. The proposed model was evaluated based on the operation of the Xiluodu hydropower system in China during the drawdown season. The results revealed a trade-off between long-term energy production and short-term peak shaving revenue, and they demonstrated the revenue potential of interprovincial hydropower transmission while meeting peak shaving demands. A comparison with other long-term optimization methods demonstrated the effectiveness and reliability of the proposed model in maximizing power generation revenue.
Investigating the Formation of Submesoscale Structures along Mesoscale Fronts and Estimating Kinematic Quantities Using Lagrangian Drifters
Authors: Lodise John , Özgökmen Tamay , Gonçalves Rafael C. , Iskandarani Mohamed , Lund Björn , Horstmann Jochen , Poulain Pierre-Marie , Klymak Jody , Ryan Edward H. , Guigand Cedric
Published: September 2020

Much of the vertical transport near the surface of the ocean, which plays a critical role in the transport of dissolved nutrients and gases, is thought to be associated with ageostrophic submesoscale phenomena. Vertical velocities are challenging not only to model accurately, but also to measure because of how difficult they are to locate in the surface waters of the ocean. Using unique massive drifter releases during the Lagrangian Submesoscale Experiment (LASER) campaign in the Gulf of Mexico and the Coherent Lagrangian Pathways from the Surface Ocean to the Interior (CALYPSO) experiment in the Mediterranean Sea, we investigate the generation of submesoscale structures along two different mesoscale fronts. We use a novel method to project Lagrangian trajectories to Eulerian velocity fields, in order to calculate horizontal velocity gradients at the surface, which are used as a proxy for vertical transport. The velocity reconstruction uses a squared-exponential covariance function, which characterizes velocity correlations in horizontal space and time, and determines the scales of variation using the data itself. SST and towed CTD measurements support the findings revealed by the drifter data. Due to the production of a submesoscale instability eddy in the Gulf of Mexico, convergence magnitudes of up to ∼20 times the planetary vorticity, f, are observed, the value of which is almost 3 times larger than that found in the mesoscale dominated Western Mediterranean Sea.
The Role of Social Support in Participation Perspectives of Caregivers of Children with Intellectual Disabilities in India and South Africa
Authors: Dada Shakila , Bastable Kirsty , Halder Santoshi
Published: September 2020

Caregivers are an intrinsic component of the environment of children with intellectual disabilities. However, caregivers’ capacity to support children’s participation may be linked to the social support that they, as caregivers, receive. Social support may increase participation, educational, psychological, medical and financial opportunities. However, there is a lack of information on social support in middle-income countries. The current study described and compared the social support of caregivers of children with intellectual disabilities by using the Family Support Survey (FSS) in India and South Africa. The different types of social support were subsequently considered in relation to participation, using the Children’s Assessment of Participation and Enjoyment (CAPE). One hundred caregiver–child dyads from India and 123 from South Africa participated in this study. The data were analysed using non-parametric measures. Indian caregivers reported greater availability of more helpful support than did the South African caregivers. Social support was associated with children’s participation diversity (India) and intensity (South Africa). The child-/caregiver-reported participation data showed different associations with participation. Results from this study suggest that perceived social support of caregivers differs between countries and is associated with their child’s participation. These factors need to be considered when generalising results from different countries.