bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic and Static Characterization of Bio-Cemented Soils
Authors: Khan Z. , Mehrabi R. , Atefi-Monfared K. , Cascante G. 
Published: September 2022

ABSTRACT:
Microbially induced calcite precipitation (MICP) is a ground improvement technique where the metabolic activities of bacteria are utilized to produce calcium carbonate precipitants at the grain contacts or within the pore spaces, enhancing bonding between the soil particles thus generating artificially cemented rocks with improved stiffness/strength properties. A key challenge in practical implementation of this technology is determining the percentage of the produced bio-cement and characterization of the resulting weakly consolidated rocks. Non-destructive techniques (NDT) are ideal for monitoring the percentage of the produced bio-cement, which is of a non-uniform and heterogenic nature, as well as the characteristics of the bio-induced cemented rock. In this study, we have conducted a series of controlled laboratory column tests where various bio-cemented samples were produced. NDT experiments including S-wave velocity measurements were taken along samples to determine bio-cementation and characterize the enhanced strength properties. Advanced signal processing techniques were conducted to interpret the findings. Results were compared against unconfined compressive tests (UCS). Findings provide a novel insight into utilization of NDT and interpretation of the results for charactering weakly consolidated rocks.

1. INTRODUCTION
Microbiological-induced calcite precipitation (MICP) is a ground improvement technique that utilizes ureolytic microorganisms capable of hydrolyzing urea to generate calcium carbonate minerals, referred to as bio-cement (Stocks-Fisher et al. 1999). The resulting enhanced engineering properties in soils treated through MICP are governed by the distribution of bio-cement at the pore-scale, which is heterogeneous and complex in nature. When the produced bio-cement is precipitated at the soil particle contacts, it can enhance bonding between soil particles thus improve shear stiffness and shear strength, compressibility and dilatancy tendencies, and liquefaction resistance (e.g., DeJong et al., 2006; Martinez and DeJong, 2009; Montoya and DeJong 2015). The hydraulic characteristics of bio-treated soils however are found to be mainly impacted by the percentage of the bio-cement produced in the pores (pore filling).
Analysis of Transparent Gelatin as a Reservoir Analogue for Hydraulic Fracturing Laboratory Experiments
Authors: Michael A. 
Published: September 2022

ABSTRACT:
Gelatin was often used as a reservoir analogue material to model hydraulic fracturing in brittle, hydrocarbon-filled rock formations, with its transparency allowing direct, visual observation of the fracture growth. Nevertheless, not many studies elaborate on the scalability of laboratory experiments where gelatin was used in comparison to actual field-scale hydraulic fracture treatments. Model laws from the literature derived to relate lab-scale physical models displaying hydraulic fracture growth to the prototype parameters are used to assess the representation of elastic deformation, crack formation energy, treatment time, and confining stress environment, honoring the governing laws of fluid-driven fracture propagation in linearly elastic media. In this work, the lab-scale parameters of an experimental study on gelatin blocks of 7-to-8%-by-weight concentration are assessed against typical slickwater and crosslinked gel fracture treatment parameters from the Barnett Shale as part of a dimensional scaling evaluation. The analysis shows the gelatin reservoir analogue scaling better against crosslinked gel compared to slickwater field operations, with the laboratory conditions accentuating Mode I fracture toughness over viscous fluid effects, compared to the field. Subsequently, a set of laboratory parameters is proposed at a higher gelatin concentration (18-to-19%-by-weight), yielding improved scalability against field operations, minimizing the difference between the lab-scale and the corresponding field-scale values of each dimensionless group, within the constraints of the available laboratory equipment. Finally, the implications of the absence of leakoff in experiments on gelatin specimens is discussed and comparisons are made between gelatin and other transparent lab-scale reservoir analogues.

1. INTRODUCTION
Analogue experimental work is –bar none– a fundamental branch of scientific method. Selecting the appropriate analogue material, which satisfies a set of criteria determining whether a candidate analogue material can be considered a laboratory version of the natural counterpart is one of the biggest challenges when developing an experimental study. This paper elaborates on the scalability of transparent gelatin as a reservoir analogue in hydraulic fracturing block experiments.
Osmotic Ion Concentration Control of Steady-State Subcritical Fracture Growth in Shale
Authors: Nguyen Hoang T. , Bažant P. Zdenek 
Published: September 2022

ABSTRACT:
The mechanism of formation of natural cracks in sedimentary rocks in the geologic past is an important problem in hydraulic fracturing. Why are the natural cracks roughly parallel and equidistant, and why is the spacing in the order of 10 cm rather than 1 cm or 100 cm? Fracture mechanics alone cannot answer these questions. Here it is proposed that fracture mechanics must be coupled with the diffusion of solute ions (Na+ and Cl− are considered here), driven by an osmotic pressure gradient. Parallel equidistant cracks are considered to be subcritical and governed by the Charles-Evans law. The evolution in solute concentration also affects the solvent pressure in the pores and cracks, altering the resistance to frictional sliding. Only steady-state propagation and periodic cracks are studied. An analytical solution of the crack spacing as a function of the properties of the rock as well as the solvent and solute, and the imposed far-field deformation is obtained. Finally, the stability of the growth of parallel cracks is proven by examining the second variation of free energy. Stability of the periodic growth state is also considered.

1 INTRODUCTION
The deep layers of sedimentary rocks such as shale and sandstone are usually intersected by systems of nearly parallel natural cracks either filled by mineral deposits or closed by creep over a million year life span. Their spacing is roughly uniform and is on the order of 0.1 m (rather than 1 m or 0.01m). These cracks likely play an important role in hydraulic fracturing for gas or oil recovery (aka fracking, fraccing or frac) (Rahimi-Aghdam et al., 2019, e.g.). Therefore, understanding the mechanism of their formation in the distant geologic past is of interest.
What controls the spacing of the nearly parallel cracks in shale? According to the fracture mechanics alone, the crack spacing is arbitrary. If propagating parallel equidistant cracks are in a critical state, stability analysis shows that many cracks would have to stop growing, causing a great increase of their average spacing, which was obviously not the case (Bažant et al., 2014).
The Impact of Strain Amplitude on Young's Modulus in Water-Saturated Sandstone
Authors: Mews K. S. , Holt R. M. , Lozovyi S. 
Published: September 2022

ABSTRACT:
Strain amplitude, frequency, stress conditions, and fluid saturation influence the stiffness response of rocks. In order to quantify the effect of frequency and strain amplitude, we performed low-frequency measurements on fully saturated Bentheimer sandstone samples to measure the dynamic stiffness at seismic frequencies (0.5 – 143 Hz) with strain amplitudes ranging from 10−7 to 10−5 . In order to quantify the effect of pressure, we increased the effective stress subsequently. The results show that Young’s modulus decreases with increasing strain amplitude even in the seismic-frequency range. The applied wave-stress signal contains the first harmonic at the central frequency, but the measured wave strain rate spectrum contains higher-order harmonics indicating hysteresis in the stress-strain response. The increased signal at higher-order harmonics is only captured for higher strain amplitudes. The general trend shows a decreasing signal with increasing order of harmonics. Remarkable is that the 3rd harmonic indicates a stronger signal than the 2nd harmonic and the 5th harmonic a stronger signal than the 4th. Understanding non-linearities and non-elastic mechanisms and their dependency on the strain amplitude for saturated samples are fundamental for the link between dynamic and static properties of reservoir rocks.

1 INTRODUCTION
It is well known that some materials show an extreme non-linear response. Studies on those non-linear effects, even for small strains, started several decades ago (Winkler et al., 1979), revealed as non-linear stress-strain, harmonic generation, non-linear attenuation, and resonant peak shift. It was found that frequency, stress, strain amplitude, and fluid saturation affect non-linearity the most (Tutuncu et al., 1998).
Van Den Abeele and Johnson (1996) found from experimental studies on Berea sandstone that non-linearity exists even on strains as small as 10−7 . The higher-order harmonic generation shows that odd harmonics dominate the even harmonics (Van Den Abeele and Johnson, 1996; Johnson and Rasolofosaon, 1996; Johnson and Rasolofosaon, 1996; Saltiel et al., 2017). Though these acoustic measurements were performed on frequencies in the kHz region (Van Den Abeele and Johnson, 1996; Johnson and Rasolofosaon, 1996). It is, however, rare to find a non-linearity description of higher-order harmonics for seismic frequency measurements (Rivière et al., 2016).
Flexible and Accessible 4D Subsurface Visualization Using a Web-Based Platform
Authors: Pratt M. J. , Knox H. A. , Johnson T. C. , Kneafsey T. J. 
Published: September 2022

ABSTRACT:
4D subsurface visualization using a web platform can provide improved communication, education and outreach to non-experts and stakeholders. It allows for the improved understanding of complex relationships and interactions that occur in inaccessible locations where many experimental testbeds exist. The use of a web-based visualization tool lessens the cognitive impact further by reducing the need of specialized software. Users can define their own exploration of a 3D or 4D scene, adding and removing data as needed, and they are able to make informed decisions based on accurate model visualizations, while providing a collaborative tool that can be accessed on any platform using a browser window. Here we show the tool with example geophysical data collected from the EGS Collab project that includes borehole logs and preliminary conductivity model results. The tool is also able to point to real time streams to display up-to-the-second data as an experiment is ongoing. This level of latency can also provide operators with essential information that can direct an experiment’s progress. Additionally, this tool can leverage augmented and virtual reality (AR, VR) capabilities of certain mobile devices and head-mounted displays, providing further engaging visualization possibilities.

1. INTRODUCTION & BACKGROUND
Three and 4D visualization is an appropriate and intuitive way to represent subsurface geophysical data. The regions of study are always inaccessible so visualization will always be required to represent collected subsurface information.
However, data visualization within the geosciences is often limited to 2D slices, static views of 3D representations flattened onto a 2D plane for publication, or a predefined camera path around a 3D structure of interest. These visuals are limiting and are often misunderstood, requiring the observer to reconstruct the 3D structures often with a lack of depth cues such as occlusion or perspective distortion.
Geophysical interpretation often requires the overlap of disparate datasets to glean the full understanding of the processes that are playing out. Visualization tools must be able to synthesize a variety of data types and formats and display them in an intuitive way to be effective. A 4D representation is the most true-to-life and therefore requires the least spatial reasoning when presented well. Furthermore, the spatial relationships between complex 3D shapes are much more intuitively understood when visualized in 3D. There is less onus on the viewer to reconstruct the 3D scene from dimension reduced cross-sections that are often used due to the current prevalence of 2D platforms such as screens and documents.
Yuk Belajar PKn Menjadi Sebuah "Alat" Bagi Guru PKn Dalam Mengembangkan Cara Mengajar dan Belajar Peserta Didik Di Era Pandemi
Authors: Rahmi Desi Afianti 
Published: September 2022

Tujuan program kegiatan Yuk Belajar PKn ini yaitu untuk mengembangkan cara mengajar dan belajar peserta didik di era pandemi dan sebagai "alat" bantu bagi guru PKn dalam mencapai pembelajaran terbaik dan efektif bagi pembelajaran dalam jaringan (online) dan luar jaringan (offline) bagi pesera didik kelas XII SMAN 1 Tamansari Bogor. Program kegiatan ini dilakukan dengan terintegrasi antara Youtube dan Google Classroom sebagai wadah untuk mudah mengaksesnya. Fitur yang diberikan Yuk Belajar PKn (yang sudah terintegrasi dengan Google Classroom) bagi siswa: Video Pembelajaran, Materi PKn dalam Powerpoint, Rangkuman dan berbagai quiz evaluasi yang bisa diakses kapanpun di manapun. Cara belajar menggunakan Yuk Belajar PKn yang sudah terintegrasi: Minggu pertama (Siswa diberikan materi berupa Video, Ppt dan rangkuman. Minggu kedua adalah melanjutkan sub pematerian sampai sub pematerian anggap selesai. Minggu ketiga adalah Ulangan harian, karena sudah mendapatkan materi yang mudah diakses. Minggu keempat adalah pengulangan, sehingga siswa lebih nyaman dalam mengakses materi pembelajaran.
Interaction of Grassland Ecosystem with Livelihood and Wildlife Sustainability: Tanzanian Perspectives
Authors: Yoram Kavana Pius , Kija Bukombe John , Kija Hamza , Nindi Stephen , Nkwabi Ally , Lipende Iddi , Maijo Simula , Naftali Baraka , M. Kakengi Victor , Ntalwila Janemary , Ndimuligo Sood , Fyumagwa Robert 
Published: September 2022

In Tanzania, pure grasslands cover is estimated to be 60,381 km2, about 6.8% of the total land area, and is distributed in different parts. These grasslands are diverse in dominant grass species depending on rainfall, soil type, altitude, and management or grazing system. They support livestock and wildlife distributed in different eco-tomes and habitats of the country. The potential of grasslands for the livelihood of rural people is explicit from the fact that local people depend solely on natural production to satisfy their needs for animal products. Analysis of grazing lands indicated that livestock population, production of meat, and milk from grasslands increased. But the wildlife population, when considered in terms of livestock equivalent units (Large Herbivore Units) showed a declining trend. The contribution of grasslands to the total volume of meat produced in the country showed a declining state, while milk production showed a slight increase. This situation entails a need to evaluate the grasslands of Tanzania to ascertain their potential for supporting people’s livestock, wildlife, and livelihood. This study concluded that more research is needed to establish the possibility of grasslands to keep large numbers of grazing herbivores for sustainable livestock and wildlife production.
Gut Microbiota and Inflammatory Bowel Disease
Authors: Vakili Bahareh , Shoaei Parisa , Esfandiari Zahra , Davar Siadat Seyed 
Published: September 2022

Inflammatory bowel disease (IBD) is a chronic and relapsing inflammatory disorder that includes Crohn’s disease and ulcerative colitis. Ulcerative colitis involves the distal colon, proximal colon, and cecum and can lead to ulcerations and bleeding. Crohn’s disease appears as patched lesions in the gastrointestinal tract and inflammation, stenosis, or fistulas. IBD affects millions of people worldwide and has been associated with high morbidity and mortality. Our intestine is colonized by trillions of microorganisms (including bacteria, viruses, fungi, and protozoa), which constitutes the microbiota. Reduction of bacteria with anti-inflammatory capacities and increase of bacteria with inflammatory capacities are observed in patients with IBD when compared with healthy individuals. Microbial balance is needed for the development of a healthy gut and a symbiotic microbiota without problems. Any disturbance in that balance leads to dysbiosis and the host may become more susceptible to disease. Some alteration in the microbiome is protective or causative; thus, we selectively will review IBD disease, pathogenesis, and potential roles of some members of microbiota in IBD. In this chapter, we also explain the therapeutic approaches targeting microbiota (probiotics, prebiotics, postbiotics) and the relationship between gut microbiota imbalance, and how defects in this dysbiosis can lead to disease.
Future Particle Accelerators
Authors: Resta López Javier 
Published: September 2022

Particle accelerators have enabled forefront research in high energy physics and other research areas for more than half a century. Accelerators have directly contributed to 26 Nobel Prizes in Physics since 1939 as well as another 20 Nobel Prizes in Chemistry, Medicine and Physics with X-rays. Although high energy physics has been the main driving force for the development of the particle accelerators, accelerator facilities have continually been expanding applications in many areas of research and technology. For instance, active areas of accelerator applications include radiotherapy to treat cancer, production of short-lived medical isotopes, synchrotron light sources, free-electron lasers, beam lithography for microcircuits, thin-film technology and radiation processing of food. Currently, the largest and most powerful accelerator is the Large Hadron Collider (LHC) at CERN, which accelerates protons to multi-TeV energies in a 27 km high-vacuum ring. To go beyond the maximum capabilities of the LHC, the next generation of circular and linear particle colliders under consideration, based on radiofrequency acceleration, will require multi-billion investment, kilometric infrastructure and massive power consumption. These factors pose serious challenges in an increasingly resource-limited world. Therefore, it is important to look for alternative and sustainable acceleration techniques. This chapter pays special attention to novel accelerator techniques to overcome present acceleration limitations towards more compact and cost-effective long-term future accelerators.
Comparative Study on Predicting Ship Maneuvering in Waves Using a Quasi-Steady Method and a Time Domain Approach
Authors: Zhang Wei , Cheng Jie , Li Xuan , He Guanghua 
Published: September 2022

_
Numerical prediction of ship maneuvering in waves was considered in this article. The wave drift loads, computed using the potential flow theory, were added into the mathematical modeling group (MMG) equations to account for the effect of waves on the ship maneuvering. Two numerical methods were tested for dealing with the coupled maneuvering-seakeeping problem, namely a time domain approach and a quasi-steady method. For the former approach, a time domain seakeeping computation was conducted that parallels to the maneuvering simulation. For the later one, it is assumed that at each time of the maneuvering process, the wave-ship interaction is in a time harmonic status and, therefore, the wave drift loads could be evaluated using a frequency domain computation. Turning maneuvers of the S-175 container ship in regular waves were numerically tested. The results of the quasi-steady method and the time domain approach show good agreements, which proved the validity of the quasi-steady assumption. The wave drift loads during the turning process were also presented, demonstrating the significant effect of the added resistance on the maneuvering prediction, in contrast to the less remarkable effects of the lateral wave drift force and the wave drift yaw moment.

Introduction
Ship maneuverability is typically predicted under calm water condition. This provides valuable information at the ship design stage. However, an actual seagoing ship usually maneuvers in waves. To reliably assess a ship’s navigation safety and total performance in a seaway, it is deemed important to understand the maneuvering behavior of a ship in waves.
Indeed, ship maneuverability in waves has been increasingly investigated in recent years. Although the physical experiment is still regarded as the most reliable way to investigate ship maneuverability in waves, there are more and more studies providing practical mathematical models of ship maneuvering prediction. Generally, a mathematical model that is suitable for investigating the maneuvering of a ship in waves has to encapsulate the traditional theories of calm water maneuvering and forward-speed seakeeping.
Lack of a genetic cline and temporal genetic stability in an introduced barnacle along the Pacific coast of Japan
Authors: Yorisue Takefumi 
Published: September 2022

Background
Large numbers of exotic marine species have been introduced worldwide. Monitoring of introduced species is important to reveal mechanisms underlying their establishment and expansion. Balanus glandula is a common intertidal barnacle native to the northeastern Pacific. However, this species has been introduced to Japan, South America, South Africa, and Europe. While a latitudinal genetic cline is well known in its native range, it is unclear whether such a genetic cline occurs in introduced areas. Twenty years have passed since it was first identified in Japan and its distribution now ranges from temperate to subarctic regions.

Methods
In the present study, we examined genotypes of cytochrome oxidase subunit I (COI) of mitochondrial (mt)-DNA and elongation factor 1a (EF1) across the distribution of B. glandula in Japan at high and mid intertidal zones.

Results
At all sampling sites, native northern genotypes are abundant and I did not detect significant effects of latitude, tide levels, or their interaction on genotypic frequencies. Further, I did not detect any change of genotype composition between data collected during a study in 2004 and samples in the present study collected in 2019. Data from the present study offer an important baseline for future monitoring of this species and supply valuable insights into the mechanisms of establishment and expansion of introduced marine species generally.