bluuebunny/crossref_metadata_2025 huggingface dataset:
A Study of Geometrical Effects on Permeability Estimation in Three-dimensional Fractures Using the Lattice Boltzmann Method
Authors: Fatimah Az-Zahra  , Irwan Ary Dharmawan
Published: October 2023

This study investigates the effect of geometry on permeability estimation in three-dimensional fractures using the Lattice Boltzmann Method. Fractures have irregular and complex shapes, which can significantly impact their permeability. Anisotropy of permeability is important as it indicates the influence of changes in fracture orientation on the flow and transport properties of fluids. To examine the relationship between permeability and fracture geometry, we generated three-dimensional fracture geometries using fractal Brownian motion with a Hurst exponent to describe the roughness on the fracture surface. The fractures in this study have varying mean aperture, ranging from narrow to wide, with surface roughness that can be either uniform or non-uniform. The Lattice Boltzmann Method was performed to calculate permeability and investigate the relationship between permeability and geometric parameters of fractures, such as mean aperture and surface roughness. Our results were in good agreement with previous studies on two-dimensional fractures. We found a clear relationship between permeability and mean aperture. Both in uniform and non-uniform geometry have the same trend as the mean aperture increased, permeability generally increased, while rougher surface roughness permeability generally decreased but in non-uniform geometry the data on the graph appears more random and irregular. We extended our investigation to real fractures by digital rock portal data. The analysis revealed that the geometry of the real fractures closely resembled non-uniform geometry, and the permeability exhibited anisotropic behaviour. In addition, the anisotropy of permeability and computation time were also investigated; and it was found that both can be influenced by the three-dimensional fracture geometry.
KLASIFIKASI KEMATANGAN TOMAT DENGAN MODEL WARNA YANG BERBEDA MENGGUNAKAN LINEAR DISKRIMINAN ANALISIS (LDA)
Authors: Astrianda Nica , Maghfirah Hayatun , Mohamad Fatma Susilawati
Published: October 2023

AbstractQuality of fruits depend heavily on the right time of plucking plus the right stage of ripeness to ensure its highest quality before selling. Tomatoes are one of the fruits that have a relatively fast maturity process. So that the classification of  tomato maturity has an  important role to reduce the risk of spoilage of tomato. Color is one of the attributes that can be used to identify the ripeness of tomato and it is one of the most distinctive characteristic of the fruits and vegetables that grow in tropical climates. In this study, the goal is to classify tomatoes maturity using color based predominant images. Linear Discriminant Analysis (LDA) is used to classify the ripeness classes based on three color models (HSV, YCbCr and CIElab). Comparisons are made between these color models for system accuracy and running time. For the highest accuracy of 95% achieved with a running time of 3,425 seconds with the CIElab color model, and a low of 67% with a running time of 3,526 seconds using the YcbCr color model, and 85% with the fastest system running time of 3,253 seconds obtained by the HSV color model.Keywords:Keywords: Linear Discriminant Analysis, HSV, YCbCr, CIELab, ripeness,  Tomatoes __________________________ AbstrakKualitas buah sangat bergantung pada waktu yang tepat untuk memetik ditambah tahap kematangan yang tepat untuk memastikan kualitas tertinggi sebelum dijual. Tomat adalah salah satu buah yang memiliki proses kematangan yang relatif cepat. Sehingga klasifikasi kematangan tomat memiliki peran penting untuk mengurangi resiko pembusukan tomat. Warna adalah salah satu atribut yang dapat digunakan untuk mengidentifikasi kematangan tomat dan itu adalah salah satu karakteristik yang paling khas dari buah-buahan dan sayuran yang tumbuh di iklim tropis. Dalam penelitian ini, tujuannya adalah untuk mengklasifikasikan kematangan tomat menggunakan gambar dominan berbasis warna. Linear Discriminant Analysis (LDA) digunakan untuk mengklasifikasikan Tingkat kematangan berdasarkan  tiga model warna berbeda yaitu  HSV, YCbCr dan CIElab. Perbandingan dibuat antara model warna ini untuk akurasi dan running time sistem. Untuk akurasi  tertinggi 95% dicapai dengan running time 3.425 detik dengan menggunakan model warna CIElab, dan terendah 67% dengan running time 3.526 detik menggunakan model warna YcbCr, dan 85% dengan running time sistem tercepat 3.253 detik diperoleh oleh model warna HSV.Kata Kunci:Kata kunci: Analisis Diskriminan Linier, HSV, YCbCr, CIELab, kematangan, Tomat
Evaluation of the Application of Sales Tax Incentives on Luxury Goods to Motor Vehicle Sales During the Covid-19 Pandemic At Pt Hasjrat Abadi Manado Tendean Branch
Authors: R. UMBOH William , SABIJONO Harijanto , SUWETJA I Gede
Published: October 2023

The Sales Tax on Luxury Goods incentive is a policy implemented by the Government which is a stimulus for the community's economy to increase and help restore the country's economy. This study aims to determine whether applying Sales Tax incentives on Luxury Goods on Motor Vehicles during the COVID-19 Pandemic affects Motor Vehicle Sales at PT Hasjrat Abadi Manado Tendean Branch. This research is descriptive qualitative research with the data used as primary data obtained from sources or informants. The results showed that the Sales Tax Incentive on Luxury Goods affects Motor Vehicle Sales at PT Hasjrat Abadi Manado Tendean Branch. This can be seen in the percentage increase in Motor Vehicle Sales of 112% for the first, 30% for the second, and 49% for the third period. Based on the data and discussion, a conclusion can be obtained that applying Sales Tax incentives on Luxury Goods during the COVID-19 period at PT Hasjrat Abadi Manado Tendean Branch is by applicable regulations and provisions.
Tax Planning Analysis on Corporate Income Tax Article 25 At PT Unoson Manado
Authors: KARLOS Sharon Ester Hermien , WANGKAR Anneke , PANGERAPAN Sonny
Published: October 2023

Tax planning is to minimize the tax burden and implement tax compliance, such as calculating, paying, and reporting the tax payable correctly and punctually. PT Unoson Manado received the SP2DK for the fiscal year 2020 with several findings, including the underpayment of Corporate Income Tax. It is caused by the error of calculating the tax burden. This research will determine whether the tax planning could prevent the calculation error in the subsequent fiscal years. The research design used in this research is qualitative with a descriptive approach. The result of this research shows that there are several things on the fiscal income statement of PT Unoson Manado for the year 2020, such as the costs are not fully specified, there is a difference in the calculation between the commercial depreciation and fiscal depreciation, and analyzing on the applicable tax regulations has not been thoroughly done. Therefore, doing the tax planning with its steps and reconciliation can prevent the calculation error in the subsequent fiscal years.
Formulating Mass-loss Rates for Sun-like Stars: A Hybrid Model Approach
Authors: Shoda Munehito , Cranmer Steven R. , Toriumi Shin
Published: October 2023

We observe an enhanced stellar wind mass-loss rate from low-mass stars exhibiting higher X-ray flux. This trend, however, does not align with the Sun, where no evident correlation between X-ray flux and mass-loss rate is present. To reconcile these observations, we propose a hybrid model for the stellar wind from solar-type stars, incorporating both Alfvén wave dynamics and flux emergence-driven interchange reconnection, an increasingly studied concept guided by the latest heliospheric observations. For establishing a mass-loss rate scaling law, we perform a series of magnetohydrodynamic simulations across varied magnetic activities. Through a parameter survey concerning the surface (unsigned) magnetic flux (Φsurf) and the open-to-surface magnetic flux ratio (ξ
open = Φopen/Φsurf), we derive a scaling law of the mass-loss rate given by

M

̇

w

/

M

̇

w
,
⊙

=

Φ

surf

/

Φ

⊙

surf

0.52

ξ

open

/

ξ

⊙

open

0.86

, where

M

̇

w
,
⊙

=
2.0
×

10

−
14

M

⊙

yr

−
1

,

Φ

⊙

surf

=
3.0
×

10

23

Mx

, and

ξ

⊙

open

=
0.2

. By comparing cases with and without flux emergence, we find that the increase in the mass-loss rate with the surface magnetic flux can be attributed to the influence of flux emergence. Our scaling law demonstrates an agreement with solar wind observations spanning 40 yr, exhibiting superior performance when compared to X-ray-based estimations. Our findings suggest that flux emergence may play a significant role in the stellar winds of low-mass stars, particularly those originating from magnetically active stars.
Statistical Signatures of Nanoflare Activity. III. Evidence of Enhanced Nanoflaring Rates in Fully Convective stars as Observed by the NGTS
Authors: Grant S. D. T. , Jess D. B. , Dillon C. J. , Mathioudakis M. , Watson C. A. , Jackman J. A. G. , Jackson D. G. , Wheatley P. J. , Goad M. R. , Casewell S. L. , Anderson D. R. , Burleigh M. R. , West R. G. , Vines J. I.
Published: October 2023

Previous examinations of fully convective M-dwarf stars have highlighted enhanced rates of nanoflare activity on these distant stellar sources. However, the specific role the convective boundary, which is believed to be present for spectral types earlier than M2.5V, plays on the observed nanoflare rates is not yet known. Here, we utilize a combination of statistical and Fourier techniques to examine M-dwarf stellar lightcurves that lie on either side of the convective boundary. We find that fully convective M2.5V (and later subtypes) stars have greatly enhanced nanoflare rates compared with their pre-dynamo mode-transition counterparts. Specifically, we derive a flaring power-law index in the region of 3.00 ± 0.20, alongside a decay timescale of 200 ± 100 s for M2.5V and M3V stars, matching those seen in prior observations of similar stellar subtypes. Interestingly, M4V stars exhibit longer decay timescales of 450 ± 50 s, along with an increased power-law index of 3.10 ± 0.18, suggesting an interplay between the rate of nanoflare occurrence and the intrinsic plasma parameters, e.g., the underlying Lundquist number. In contrast, partially convective (i.e., earlier subtypes from M0V to M2V) M-dwarf stars exhibit very weak nanoflare activity, which is not easily identifiable using statistical or Fourier techniques. This suggests that fully convective stellar atmospheres favor small-scale magnetic reconnection, leading to implications for the flare-energy budgets of these stars. Understanding why small-scale reconnection is enhanced in fully convective atmospheres may help solve questions relating to the dynamo behavior of these stellar sources.
Hidden Companions to Intermediate-mass Stars. XII. Discovery of a 1.8 M
⊙, 1.3 au Companion to Delta Serpentis A*
Authors: Waisberg Idel , Klein Ygal , Katz Boaz
Published: October 2023

Delta Serpentis is a nearby 4″ visual binary (A+B) that has accrued a number of astrometric anomalies. Here we show that the primary component is actually a close binary based on a VLTI/GRAVITY archival interferometric observation. The newly discovered companion has a K band flux ratio of 33% at a projected separation ρ = 23.9 mas ↔ 1.3 au. Through isochrone fitting we find somewhat evolved 1.2 Gyr old M
Aa = 1.98 M
⊙, M
Ab = 1.80 M
⊙ and M
B = 1.88 M
⊙ stars. Delta Ser joins a growing list of intermediate mass hierarchical multiples and may be a progenitor of a rather rare system of three white dwarfs.
OSIRIS-APEX: An OSIRIS-REx Extended Mission to Asteroid Apophis
Authors: DellaGiustina Daniella N. , Nolan Michael C. , Polit Anjani T. , Moreau Michael C. , Golish Dathon R. , Simon Amy A. , Adam Coralie D. , Antreasian Peter G. , Ballouz Ronald-Louis , Barnouin Olivier S. , Becker Kris J. , Bennett Carina A. , Binzel Richard P. , Bos Brent J. , Burns Richard , Castro Nayessda , Chesley Steven R. , Christensen Philip R. , Crombie M. Katherine , Daly Michael G. , Daly R. Terik , Enos Heather L. , Farnocchia Davide , Freund Kasper Sandra , Garcia Rose , Getzandanner Kenneth M. , Guzewich Scott D. , Haberle Christopher W. , Haltigin Timothy , Hamilton Victoria E. , Harshman Karl , Hatten Noble , Hughes Kyle M. , Jawin Erica R. , Kaplan Hannah H. , Lauretta Dante S. , Leonard Jason M. , Levine Andrew H. , Liounis Andrew J. , May Christian W. , Mayorga Laura C. , Nguyen Lillian , Quick Lynnae C. , Reuter Dennis C. , Rivera-Valentín Edgard , Rizk Bashar , Roper Heather L. , Ryan Andrew J. , Sutter Brian , Westermann Mathilde M. , Wibben Daniel R. , Williams Bobby G. , Williams Kenneth , Wolner C. W. V.
Published: October 2023

The Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) spacecraft mission characterized and collected a sample from asteroid (101955) Bennu. After the OSIRIS-REx Sample Return Capsule released to Earth’s surface in 2023 September, the spacecraft diverted into a new orbit that encounters asteroid (99942) Apophis in 2029, enabling a second mission with the same unique capabilities: OSIRIS–Apophis Explorer (APEX). On 2029 April 13, the 340 m diameter Apophis will draw within ∼32,000 km of Earth’s surface, less than 1/10 the lunar distance. Apophis will be the largest object to approach Earth this closely in recorded history. This rare planetary encounter will alter Apophis’s orbit, will subject it to tidal forces that change its spin state, and may seismically disturb its surface. APEX will distantly observe Apophis during the Earth encounter and capture its evolution in real time, revealing the consequences of an asteroid undergoing tidal disturbance by a major planet. Beginning in 2029 July, the spacecraft’s instrument suite will begin providing high-resolution data of this “stony” asteroid—advancing knowledge of these objects and their connection to meteorites. Near the mission’s end, APEX will use its thrusters to excavate regolith, a technique demonstrated at Bennu. Observations before, during, and after excavation will provide insight into the subsurface and material properties of stony asteroids. Furthermore, Apophis’s material and structure have critical implications for planetary defense.
Milestone MS32 The design and prototype of a workflow integrating Wikidata into validation and linking
Authors: Dillen Mathias , Plank Andreas
Published: October 2023

In this task, the aim is to develop a workflow that should facilitate the linking process of collector name strings to PIDs for those collectors. Such a workflow should help scale up the number of links being made, make the process more efficient and should take advantage as much as possible of existing work and infrastructures, so as not to reinvent the wheel. As such, the work can be roughly split into a few subtasks:- Make existing linking workflows more easily implementable in other contexts and by other infrastructures. This includes finding ways for such workflows to produce links that can easily be published, i.e. in a standardised format compatible with existing infrastructure. The suitability of different infrastructures for making established links available should also be assessed.- Establish, document and improve the comprehensiveness, findability and interoperability of the content in PID-minting resources, in particular Wikidata as it can be edited openly.- Refine the decision making process of establishing links, by implementing and improving the methods that can be used to validate potential links.

In this document, the focus lies on linking people. We will propose a workflow to 'roundtrip' links established through the Bionomia platform back to the collections holding the attributed specimens, as well as making them available for use by other BiCIKL infrastructures. We will also refine existing automated linking workflows and pilot the new functionalities on the (botanical) collections of the task partners. These refinements will be influenced by an assessment of the current state of Wikidata, investigated through shape expressions constructed from commonly used queries and from Wikidata records which have been linked in previous efforts such as the Botany Pilot, Bionomia and published specimen data to GBIF.
Methods and techniques for increasing the safety and efficacy of pulmonary vein isolation in patients with atrial fibrillation
Authors: Dzhinsov Krasimir R.
Published: October 2023

The most common type of sustained arrhythmia is atrial fibrillation (AF). Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation for atrial fibrillation, which has emerged as the primary therapeutic strategy for atrial fibrillation patients. Unfortunately, about one-third of patients experience recurrent atrial arrhythmias after the procedure.

The leading cause of AF recurrence after PVI, especially during the first year, is reconnection of the pulmonary veins. There are different techniques and methods that could increase the efficacy of the procedure by making durable pulmonary vein isolation.

A literature search was conducted using the terms atrial fibrillation, ablation, pulmonary vein isolation, and durable PVI in the PubMed, Scopus, and Web of Science databases. Durable pulmonary vein isolation could be achieved by avoiding gaps in the ablation line and PV reconnections using pharmacological testing, waiting time, various indexes based on data from the electroanatomical mapping system, and special ablation catheters. Furthermore, detecting the gaps in the ablation line in the end of the procedure using different pacing and mapping techniques and application of additional energy to close those gaps could increase the success rate of the procedure.

Most commonly, AF recurrence after PVI is due to PV reconnections caused by gaps in the ablation line. To achieve safer and more effective PVI, the procedure has to be standardized and operator-independent with reproducible success rate and safety profile.
Diabetes mellitus as a risk factor and comorbidity in gout
Authors: Rotaru Larisa , Groppa Liliana , Russu Eugeniu , Chișlari Lia , Codreanu Cătălin , Spinei Larisa , Arnaut Oleg , Cornea Cornelia
Published: October 2023

Introduction: Metabolic disorders are a public health issue because of the complications they cause, but they are also a major risk factor for the onset of gout.

Aim: The current study set out to demonstrate clinically how the clinical-paraclinical evaluation methodology had advanced as well as to assess comorbidity in gout patients using diabetes mellitus (DM). We also wanted to examine the pancreatic dysfunction in gout patients of different ages (by assessing the glucose and glycolated Hb analyses).

Materials and methods: Two hundred gout patients (mean age, men 60±8.0 years, women 63±9.0 years) were included in a descriptive, cross-sectional study. The diagnosis of gout was made according to the classification criteria for gout according to ACR and EULAR 2015. The raw data were analyzed using SPSS v. 26.0.

Results: In the study, type 2 diabetes mellitus (DM2) was encountered with a comparable frequency among both middle-aged and elderly patients (33.8% and 41.8%, respectively, p=0.26). In only 15% of cases, DM2 preceded the development of gout (in 3% with the beginning and 12% with late onset), while the developmental age of the DM2 prior to gout was comparable (50.9±2.8 years in age group 1 and 55.1±6.9 years in age group 2). We found that elderly people experience gout much more frequently (up to 41%) when DM2 is present. However, DM2 is not considered a predictor of gout.

Conclusions: In gout patients under the age of 59 inclusive, the mean age at diabetes onset is significantly lower than the age (37.49.6 years) at which diabetes develops in the general population. Early onset of diabetes is associated with early development of gout.
Traumatic head injuries in Moldova: a cross-sectional analysis of medical registry data
Authors: Cociu Svetlana , Hamann Cara J. , Cebanu Serghei , Cazacu-Stratu Angela , Coman Mădălina Adina , Peek-Asa Corinne
Published: October 2023

Aim: The aims of this study were to evaluate the demographics and crash profiles of road traffic-related traumatic brain injury (TBI) patients treated at two emergency departments in the Republic of Moldova, and to identify areas for prevention.

Materials and methods: A prospective study was conducted using data from the medical records of a pilot TBI registry from the emergency departments of two large hospitals in Moldova. The study sample included patients with TBI related to road traffic mechanisms from March 1 to August 31, 2019.

Results: During the study period, 368 patients were included in the TBI registry, with 113 (30.7%) of them having TBIs caused by traffic. Children under the age of 18 (44.2%), people aged 30-49 (18.6%), and males (71.7%) were the largest proportions of the road traffic-related TBI patient population. Most (78.8%) of the TBI injuries occurred in a transportation area (street, road, highway, etc.), among children under age of 18, while walking (36.7%) or riding in a passenger vehicle (68.4%). Pedestrians (42.5%) accounted for the most cases, followed by passengers (33.6%) and drivers (23.9%). Over two-thirds of all cases were tested for alcohol. Most cases were in June (20.4%) and between 2 pm and 6 pm (29.2%) within the research period.

Conclusions: This is the first study to examine the road traffic-related traumatic brain injuries in the Republic of Moldova, which underlines the high burden of injuries among males, children, and the middle-aged population. Results from this study will help to support the development of a country’s national TBI registry and can argue for the running of comprehensive measures in road injury prevention targeted to the most affected populations
The year in cardiovascular medicine 2022: the top 10 papers in cardiovascular imaging
Authors: Bucciarelli-Ducci Chiara , Ajmone-Marsan Nina
Published: October 2023

The year in cardiovascular medicine 2022: the top 10 papers in cardiovascular imaging
Complete mitochondrial genome of the abyssal coral Abyssoprimnoa gemina Cairns, 2015 (Octocorallia, Primnoidae) from the Clarion-Clipperton Zone, Pacific Ocean
Authors: Gastineau Romain , Dąbek Przemysław , Mianowicz Kamila , Stoyanova Valcana , Krawcewicz Artur , Abramowski Tomasz
Published: October 2023

The Clarion-Clipperton Zone (CCZ) in the tropical East Pacific is a region of interest for deep-sea mining due to its underwater deposits of polymetallic nodules containing economically important metals such as nickel, copper, and cobalt. It is also a region of extensive baseline studies aiming to describe the state of the environment, including the biodiversity of the benthic fauna. An abundant component of the abyssal plain ecosystem consists of sessile fauna which encrusts polymetallic nodules and are vulnerable to potential impacts arising from exploitation activities, particularly removal of substrate. Therefore, this fauna is often considered to have key species whose genetic connectivity should be studied to assess their ecological resilience. One such species is Abyssoprimnoa gemina Cairns, 2015, a deep-sea coral from the CCZ whose presence in the Interoceanmetal Joint Organization (IOM) claim area has been confirmed during samplings. In this study, we used next-generation sequencing (NGS) to obtain the 18S nuclear rRNA gene and the complete mitochondrial genome of A. gemina from IOM exploration area. The mitogenome is 18,825 bp long and encodes for 14 protein coding genes, 2 rRNAs, and a single tRNA. The two phylogeny reconstructions derived from these data confirm previous studies and display A. gemina within a highly supported cluster of seven species whose mitogenomes are all colinear and of comparable size. This study also demonstrates the suitability of NGS for DNA barcoding of the benthic megafauna of the CCZ, which could become part of the IOM protocol for the assessment of population diversity and genetic connectivity in its claim area.
The Effect of Environmental Albedo on the Energy Use of a Selected House in Amman-Jordan
Authors: Alrwashdeh Saad S.
Published: October 2023

I explore the effect that albedo has on the amount of solar energy collected as well as the effectiveness of various building materials used in Jordan's varied construction industry. Albedo, which is the reflection of incoming radiation by surfaces, is of crucial relevance in minimizing the damage that solar radiation may do to building components like windows. The construction sector in Jordan is a substantial contributor to the overall level of energy consumption in the country because of the wide variety of building types, purposes and technologies found there. The findings of this research show that substances with greater albedo values produce the best results in terms of energy gains. These findings are supported by in-depth albedo value analyses and provide useful insights that may be used to improve building design and construction methods in Jordan, which will eventually lead to increased energy efficiency and sustainability within the construction sector.
A comprehensive review of nature-based solutions: current status and future research
Authors: Fu Hongpeng
Published: October 2023

Climate change and the rapid development of cities have brought considerable challenges to the sustainable development of urban and rural areas, and using nature-based solutions to strengthen ecosystems' resilience and response capacity has become a consensus strategy. Natural solutions are the collective name for all solutions that increase the city's resilience while benefiting the environment and humanity. To deepen the theoretical research and practical development of NBS, I reviewed 87 papers on NBS through the Web of Science database. The study found that NBS-related research mostly focuses on five aspects: Concept of ideas, applied technology, implementation guidelines, performance evaluation and platform building. Currently, the emphasis is predominantly on ideas and platform development in developed countries. While the other three domains were also explored, they primarily adhere to conventional methodologies and content within the NBS context. While NBS research covered many areas and boasts an integrative, collaborative approach, it remained fragmented and lacked a cohesive system. On this basis, I proposed a systematic framework to strengthen the systematicity of the NBS system, give full play to the unique advantages of NBS as a comprehensive concept and promote the specific implementation and development of NBS. I examined NBS's progression and benefits, providing a thorough insight into its significance in sustainable urban development. The research introduced a cohesive framework by elucidating NBS's foundational concepts guiding subsequent inquiries. Such findings are pivotal for facilitating informed strategies and enhancing resilience to climate adversities, underscoring a comprehensive approach to sustainability.
Analysis of soliton phenomena in (2+1)-dimensional Nizhnik-Novikov-Veselov model via a modified analytical technique
Authors: Noor Saima , Alshehry Azzh Saad , Khan Asfandyar , Khan Imran
Published: October 2023

The present research applies an improved version of the modified Extended Direct Algebraic Method (mEDAM) called $ r $+mEDAM to examine soliton phenomena in a notable mathematical model, namely the (2+1)-dimensional Nizhnik-Novikov-Veselov Model (NNVM), which possesses potential applications in exponentially localized structure interactions. The generalized hyperbolic and trigonometric functions are used to disclose a variety of soliton solutions, including kinks, anti-kink, bell-shaped and periodic soliton. Some 3D graphs are plotted for visual representations of these solutions which highlight their adaptability. The results provide a basis for practical usage and expansions to related mathematical models or physical systems. They also expand our understanding of the NNVM's dynamics, providing insights into its behavior and prospective applications.
Eisenstein field BCH codes construction and decoding
Authors: Sajjad Muhammad , Shah Tariq , Xin Qin , Almutairi Bander
Published: October 2023

First, we will go through the theory behind the Eisenstein field (EF) and its extension field. In contrast, we provide a detailed framework for building BCH codes over the EF in the second stage. BCH codes over the EF are decoded using the Berlekamp-Massey algorithm (BMA) in this article. We investigate the error-correcting capabilities of these codes and provide expressions for minimal distance. We provide researchers and engineers creating and implementing robust error-correcting codes for digital communication systems with detailed information on building, decoding and performance assessment.
Topological characteristic factors and nilsystems
Authors: Glasner Eli , Huang Wen , Shao Song , Weiss Benjamin , Ye Xiangdong
Published: October 2023

We prove that the maximal infinite step pro-nilfactor

X_\infty

of a minimal dynamical system

(X,T)

is the topological characteristic factor in a certain sense. Namely, we show that by an almost one-to-one modification of

\pi:X \rightarrow X_\infty

, the induced open extension

\pi^{*}:X^{*} \rightarrow X^*_\infty

has the following property: for

x

in a dense

G_\delta

subset of

X^*

, the orbit closure

L_x=\overline{\mathcal{O}}((x,\ldots,x),\allowbreak T\times\nobreak T^2\times\nobreak \cdots \times T^d)

is

(\pi^*)^{(d)}

-saturated, i.e.,

L_x=((\pi^*)^{(d)})^{-1}(\pi^*)^{(d)}(L_x)

. Using results derived from the above fact, we are able to answer several open questions: (1) if

(X,T^k)

is minimal for some

k\ge 2

, then for any

d\in \mathbb{N}

and any

0\le j<k

there is a sequence

\{n_i\}

of

\mathbb{Z}

with

n_i\equiv j\ (\text{mod}\ k)

such that

T^{n_i}x\rightarrow x, T^{2n_i}x\rightarrow x, \ldots, T^{dn_i}x\rightarrow x

for

x

in a dense

G_\delta

subset of

X

; (2) if

(X,T)

is totally minimal, then

\{T^{n^2}x:n\in\mathbb{Z}\}

is dense in

X

for

x

in a dense

G_\delta

subset of

X

; (3) for any

d\in\mathbb{N}

and any minimal t.d.s. which is an open extension of its maximal distal factor,

\mathbf{RP}^{[d]}=\mathbf{AP}^{[d]}

, where the former is the regionally proximal relation of order

d

and the latter is the regionally proximal relation of order

d

along arithmetic progressions.
Using Analysis of the Ring Pack and Piston to Optimize Oil Consumption of Current and Future Engines
Authors: Jay Alastair , Ballard Helen , Ocerin Meñica Olatz , Larralde Yoller Aitor , Barcena Ortiz de Urbina Javier
Published: October 2023

Engine manufacturers are increasingly concerned about oil consumption due to its implications for operating costs, emissions, and durability in both diesel and natural gas-powered engines. As future engines aim for low or near-zero emissions while utilizing low/zero carbon fuels, lubricant oil consumption will play a critical role in achieving decarbonization and emissions targets. Hydrogen-fuelled engines, in particular, will be more vulnerable to oil droplet and oil ash-based pre-ignition. Traditionally, the influence of key design parameters on oil consumption has been determined during the validation phase of an engine development program, which entails extensive testbed hours and time-consuming hardware iterations. As a result, development programs may be unable to optimize oil consumption due to cost and time constraints. The need to reduce oil consumption, along with these constraints, has prompted the adoption of more efficient development approaches, such as using virtual models to evaluate numerous design parameters before hardware implementation. In this paper, we discuss the development of an analytical method, designed to optimize oil consumption by analyzing ring pack & gas dynamics, and oil transport mechanisms for a Guascor Power E-Series gas engine. This method involved identifying the primary predicted factors contributing to oil consumption, isolating oil transport mechanisms for each piston ring, and subsequently developing and testing a series of design modifications to eliminate or improve oil origins. The optimization results indicated that a significant reduction in oil consumption could be achieved by altering specific details of the piston and ring pack design, while maintaining oil films for durability.
Evaluating Thermal Performance of Electric Motor with Hybrid Approach of 1D LPTN Model and 3D CHT Analysis
Authors: Deshmukh Shardul , Patil Uday
Published: October 2023

Electric Vehicles is the new trend in automotive industry and differentiator is electric motors which are taking over a conventional internal combustion engine. One of the major challenges with electric vehicles is the efficiency of E-drives, which is mainly affected by motor operating temperatures. Temperature affects the motor characteristics (torque vs speed), which could result in motor underperform or even fail to perform. Hence, it is critical to develop and design a methodology which can accurately predict the electric motor thermal behaviour in advance or try different iterations before getting in to a detailed and extensive analysis. The correct identification of temperatures inside the motor at different drive cycles, has always been a challenge. Experimental validation of motors gives accurate temperature measurements, but it has dependencies on prototypes which costs heavily, and feedback is not available at design stage. Another way is to have detailed 3D Simulations at early stage of design, but it is time consuming for model building and solving which delays the design phase. To solve this, a combined hybrid method of 1D Lumped Parameter Thermal Network (LPTN) approach and 3D Conjugate heat transfer (CHT) approach is proposed. In the proposed approach, detailed multidisciplinary discretized 1D LPTN model method is developed to predict temperature distribution for input drive cycles. 1D LPTN model has fidelity to analyse any drive cycle and incorporate electromagnetic, mechanical and friction generated heat losses which gives reasonably accurate temperature identification at faster solving rates. After identifying the worst cases based on 1D analysis, detailed 3D CHT finite element analysis is used to understand the temperature sweeps, rises and hot spots on the motor components at shortlisted drive cycle cases. This hybrid (1D LPTN and 3D CHT) approach, will help in early design stage by predicting motor temperatures quickly and efficiently, which saves product development time. In this Hybrid approach, the 1D and 3D thermal models are optimised and then validated with test data to establish the method.
Experimental Comparison of a Rotary Valvetrain on the Performance and Emissions of a Light Duty Spark Ignition Engine
Authors: Gainey Brian , Vaseleniuck Darrick , Cordier Dan , Garrett Norman
Published: October 2023

Rotary valve technology can provide increased flow area and higher discharge coefficients than conventional poppet valves for internal combustion engines. This increase in intake charging efficiency can improve the power density of four-stroke internal combustion engines, particularly at high engine speeds, where flow is choked through conventional poppet valves.

In this work, the valvetrain of a light duty single cylinder spark ignition engine was replaced with a rotary valve train. The impact of this valvetrain conversion on performance and emissions was evaluated by comparing spark timing sweeps with lambda ranging from 0.8 to 1.1 at wide open throttle. The results indicated that the rotary valvetrain increased the amount of air trapped at intake valve closing and resulted in a significantly faster burn duration than the conventional valvetrain. Additionally, the spark to CA10 burn duration of the rotary valvetrain was highly sensitive to spark timing, which was not true of the baseline engine, nor is it true of conventional spark ignition engines in general.

The explanation behind this rapid combustion and high combustion duration sensitivity to spark time is related to the large amount of tumble induced by the flow through the rotary valve, which is unabated axially downward unlike with a poppet valve. Thus, the rotary valve showed not only improved power density, but more rapid combustion. However, the rotary valve does introduce channels which appear to have negatively impacted unburned hydrocarbon emissions. To complete the study, a load sweep was performed at 3300 rpm, demonstrating that there was a slight brake specific NOx benefit to the rotary valvetrain despite producing higher unburned hydrocarbons, particularly at part load operation.
High-Load Engine Simulation of Renewable Diesel Fuel Using A Reduced Mechanism
Authors: Cung Khanh , Jha Prabhat Ranjan , Briggs Thomas , Smith Edward , Michlberger Alexander , Abidin Zainal , Bitsis Chris
Published: October 2023

According to the Annual Energy Outlook 2022 (AEO2022) report, almost 30% of the transport sector will still use internal combustion engines (ICE) until 2050. The transportation sector has been actively seeking different methods to reduce the CO2 emissions footprint of fossil fuels. The use of lower carbon-intensity fuels such as Renewable Diesel (RD) can enable a pathway to decarbonize the transport industry. This suggests the need for experimental or advanced numerical studies of RD to gain an understanding of its combustion and emissions performance.

This work presents a numerical modeling approach to study the combustion and emissions of RD. The numerical model utilized the development of a reduced chemical kinetic mechanism for RD’s fuel chemistry. The final reduced mechanism for RD consists of 139 species and 721 reactions, which significantly shortened the computational time from using the detailed mechanism. Both zero-dimensional (0D) and three-dimensional (3D) computational fluid dynamics (CFD) simulations showed comparable auto-ignition chemistry of RD between reduced and detailed mechanisms. Moreover, the reduced mechanism was successfully validated with the collected single-cylinder engine (SCE) experiment on both combustion and emissions performance. The characteristics uniquely associated with RD compared to conventional diesel were also relatively well captured. Results from CFD simulation showed significantly lower soot emissions with RD compared to diesel, which was in agreement with the engine experimental findings. All simulations were carried out under a high engine load condition (19 bar gIMEP at 1200 RPM). This study shows CFD results for the simulation of RD fuel at both stock and high compression ratio (CR=17:1 and CR=22:1) combustions systems. The currently developed model can be used to guide further development of the combustion system using RD fuel.
Analysis of Hydrogen Combustion in a Commercial Vehicle Engine Using 1D Simulation and Subsequent CFD Simulation
Authors: Wintergoller Dmitrij , Dafis Aristidis , Rottengruber Hermann
Published: October 2023

To meet emission targets, alternative fuels are increasingly vital in reducing exhaust emissions. One effective and cost-efficient method to achieve sustainable emission reductions is through hydrogen (H2) operated modern combustion engines. In line with the energy transformation, similar to Germany’s “Energiewende”, industries need CO2-neutral solutions, with special importance in the mobility sector. Hydrogen, as a carbon-free fuel, presents a viable alternative to conventional options and has been subject to extensive scientific research.

The development of hydrogen combustion engines is still in the conceptualization phase. This study focuses on a direct-injection (DI) combustion engine from a commercial vehicle converted from diesel DI-compression ignition (CI) to hydrogen DI-spark ignition (SI) operation. The main objectives were to validate simulation models using 1D and 3D simulation software and to conduct a comprehensive analysis of engine operation. The 1D simulation utilized a predictive combustion model, offering the advantage of analyzing operating points not covered by available measurements. The 3D simulation employed a chemical mechanism describing the reaction kinetics of hydrogen combustion in air.

GT-Power, a commercial software, was used for preliminary 1D analysis, forming the foundation for subsequent 3D CFD simulations in AVL FIRE®. The study aimed to analyze mixture formation, temperature distribution, and emissions formation. The paper presents the outcomes of this initial investigation, focusing on essential findings and derived conclusions while addressing potential difficulties and barriers. The study aims to provide a robust groundwork for future projects in this domain.
Evaluating the Impact of Oil Viscoelasticity on Bearing Friction
Authors: Michlberger Alexander , Bachu Pruthvi , Bitsis Daniel Christopher , Pashkoviski Eugene , Qureshi Farrukh , Patterson Reid , Halley Scott
Published: October 2023

In this work, a novel bearing test rig was used to evaluate the impact of oil viscoelasticity on friction torque and oil film thickness in a hydrodynamic journal bearing. The test rig used an electric motor to rotate a test journal, while a hydraulic actuator applied radial load to the connecting rod bearing. Lubrication of the journal bearing was accomplished via a series of axial and radial drillings in the test shaft and journal, replicating oil delivery in a conventional engine crankshaft. Journal bearing inserts from a commercial, medium duty diesel engine (Cummins ISB) were used. Oil film thickness was measured using high precision eddy current sensors. Oil film thickness measurements were taken at two locations, allowing for calculation of minimum oil film thickness. A high-precision, in-line torque meter was used to measure friction torque. Four test oils were prepared and evaluated. The first was a monograde, Newtonian oil, while the remaining three oils were multigrade oils having varying levels of viscoelasticity. Importantly, each test oil was carefully blended to ensure similar kinematic and high temperature high shear viscosities, isolating viscoelasticity as the only variable. Viscoelasticity was quantified as Trouton ratio (ratio of extensional to shear viscosity), and ranged from approximately 64 to 162, for the viscoelastic oils. Results for bearing friction and oil film thickness are presented at various operating speeds and loads. All multigrade oils were observed to produce lower friction torque compared to the monograde baseline. Among the multigrade oils, minimum oil film thickness was observed to increase with increasing viscoelasticity. However, only a single multigrade oil (highest viscoelasticity) resulted in a larger minimum oil film thickness compared to the monograde baseline.
Ammonia Emissions from Combustion in Gasoline Engines
Authors: Bajwa Abdullah , Shankar Varun , Leach Felix
Published: October 2023

Forthcoming worldwide emissions regulations will start regulating ammonia emissions from light duty vehicles. At present, most light duty vehicles are powered by gasoline spark ignition engines. Sources of ammonia emission from such engines can be in-cylinder reactions (i.e. combustion) or downstream reactions across aftertreatment devices, particularly three-way catalysts. The latter has been known to be a major source of ammonia emissions from gasoline vehicles and has been extensively investigated. The former (combustion), less so, and thus is the subject of this work. A two-zone thermodynamic spark ignition engine model with a comprehensive chemical kinetics framework (C3MechV3.3 mechanism), after being validated against experimental ammonia emissions data, is used to study ammonia formation during combustion. Reaction pathways responsible for its generation are analysed and the effects of changing the following engine operational and combustion parameters are explored: engine load, start of combustion, combustion duration, fuel-air equivalence ratio, and exhaust gas recirculation fraction.

Ammonia production was found to be slower than that of other major pollutant species - starting late during the heat release stage, peaking around the time when the cylinder pressures and temperatures were at their highest, and having a late, prolonged production stage after the end of heat release. Ammonia concentrations did not ‘freeze’ until late into the expansion process. Initial ammonia production was driven by three body elementary reactions involving hydrogen radicals produced from the fuel oxidation/reduction, and the late-stage production was dominated by H2O reactions with amino radicals. The net effect of these production pathways on ammonia emissions in response to changes in engine operation was non-monotonic and depended on the dominant pathway at the particular thermal conditions. However, overall trends suggested that emissions increased when engine load increased, combustion duration shortened, combustion timing advanced, fuel-air mixture became richer and exhaust gas recirculation fraction decreased.
Simulation and On-Road Testing of VTS on a Heavy Duty Diesel Engine Truck
Authors: Iddum Vivek , Bair John , Chahal Iqbal Singh , Mason Paul , Ghantasala Muralidhar K.
Published: October 2023

Estimated engine torque is an important parameter used by automotive systems for automated transmission and clutch control. Heavy-duty engine and transmission manufacturers widely use SAE J -1939 based ECU torque calculation based on mass air/fuel flow steady state maps created during calibration of the engine for this purpose. As an alternative, to enhance the accuracy of this important control variable, a virtual flywheel torque sensor (VFTS) was developed. It measures the engine torque based on the harmonics of the instantaneous flywheel speed signal. Initial dynamometer testing showed the VFTS estimated torque values exhibited a maximum inaccuracy of 12% of the actual measured torque over the range of conditions tested. In this paper we report the results of on road truck testing of the VFTS. A loaded heavy truck with a gross vehicle weight rating of 80,000 pounds was used. The performance of the VFTS was tested in different gears at full throttle in the diesel engine speed range of 1000 RPM to 1900 RPM. The accuracy of the VFTS sensor is found to vary with gear ratio, depending on the speed and road conditions. The VFTS showed better accuracy in higher gears than in lower gears. Further, an AMEsim truck drivetrain dynamic modelling was performed for comparing and analyzing the performance of the VFTS with test results under different load and speed conditions in different gears. These results showed good agreement between the simulation and experiment at full throttle in high gears.
Investigation of the Effect of Pre-Chamber Specifications on Pre-Chamber Jet Combustion Characteristics Using an Optically Accessible Engine
Authors: Chiba Takaaki , UGAJIN Taisei , Shinozaki Kaito , Tahara Ryota , Sugiyama Ryo , Iijima Akira
Published: October 2023

This study focused on a lean-burn regime using a pre-chamber for improving the efficiency of internal combustion engines. Combustion images were visualized using a two-stroke, single-cylinder, optically accessible engine fitted with a cylindrical pre-chamber. The L/D ratio of the pre-chamber length (L) to its diameter (D) and the diameter of the pre-chamber orifice were varied as parameters. Combustion characteristics were analyzed based on the visualized jet flow configuration and combustion chamber pressure measurements. The results revealed that the combustion duration tended to be longer with a smaller L/D ratio and that the coefficient of variation (COV) of the indicated mean effective pressure (IMEP) was smaller and more stable. With a smaller orifice diameter, the jet velocity was faster, and the flame development duration was shorter, but the combustion duration was longer; IMEP tended to be lower, but the COV of IMEP was smaller.