bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of the surface species in electrochemical promotion: ethylene oxidation over a Pt/YSZ catalyst
Authors: Toghan Arafat , Greiner Mark , Knop-Gericke Axel , Imbihl Ronald
Published: September 2021

In situNAP-XPS (near ambient pressure X-ray photoelectron spectroscopy) of the O 1s core level comparing electrochemically produced oxygen spillover with oxygen adsorbing from the gas phase on a Pt/YSZ catalyst at 0.25 mbar total pressure.
Structural evolution from the CdSSe alloy to the CdS/CdSe core/shell in Cd(S and Se) composite quantum dots and its impact on the performance of sensitized solar cells
Authors: Fang Junfei , Lv Wenlei , Lei Yilong , Deng Jianping , Zhang Pengchao , Huang Wendeng
Published: September 2021

The deposition process of CdS-CdSe composite QDs is realized by SILAR, which is a layer-by-layer (LbL) technique. One LbL cycle consists of the successive deposition of CdS and CdSe.
Bi- and trinuclear coinage metal complexes of a PNNP ligand featuring metallophilic interactions and an unusual charge separation
Authors: Dahlen Milena , Kehry Max , Lebedkin Sergei , Kappes Manfred M. , Klopper Wim , Roesky Peter W.
Published: September 2021

Homometallic bi- and trinuclear complexes of Cu, Ag and Au ligated by a tetradentate PNNP ligand are shown. Photoluminescence and theoretical studies revealed a MLCT character upon UV excitation and complemented this work.
A comparative study of honeycomb-like 2D π-conjugated metal–organic framework chemiresistors: conductivity and channels
Authors: Yao Ming-Shui , Wang Ping , Gu Yi-Fan , Koganezawa Tomoyuki , Ashitani Hirotaka , Kubota Yoshiki , Wang Zao-Ming , Fan Ze-Yu , Otake Ken-ichi , Kitagawa Susumu
Published: September 2021

Honeycomb-like 2D π-conjugated conductive metal–organic framework gas sensors with channel sizes <2 nm and broad conductivity range are studied with low conductivity facilitating response, multi-porosity and short channel resulting in fast speed.
Dinuclear gold(i) complexes with N-phosphanyl, N-heterocyclic carbene ligands: synthetic strategies, luminescence properties and anticancer activity
Authors: Trevisan Gianmarco , Vitali Valentina , Tubaro Cristina , Graiff Claudia , Marchenko Anatoliy , Koidan Georgyi , Hurieva Anastasiia N. , Kostyuk Aleksandr , Mauceri Matteo , Rizzolio Flavio , Accorsi Gianluca , Biffis Andrea
Published: September 2021

Novel dinuclear Au complexes with NHCP ligands have been prepared, exhibiting tuneable luminescence properties and in vitro anticancer activity, which were found to depend on complex charge and ligand substitution.
A ruthenium cis-dihydride with 2-phosphinophosphinine ligands catalyses the acceptorless dehydrogenation of benzyl alcohol
Authors: Trodden Elizabeth C. , Delve Matthew P. , Luz Christian , Newland Robert J. , Andresen John M. , Mansell Stephen M.
Published: September 2021

The first ruthenium dihydride stabilised with phosphinine ligands is described. Formed in situ, it was shown to catalyse the acceptorless dehydrogenation (AD) of benzyl alcohol to benzyl benzoate.
Facile synthesis ofcyclo-(P4tBu3)-containing oligo- and pnictaphosphanes
Authors: Eilrich Volker Jens , Grell Toni , Lönnecke Peter , Hey-Hawkins Evamarie
Published: September 2021

Activation of white phosphorus enables the facile synthesis of novel oligo- and pnictaphosphanes including the first examples of a tri-coordinate group 15 element with an EP3substructure.
Homogeneous hydrogenation of saturated bicarbonate slurry to formates using multiphase catalysis
Authors: Rebreyend Christophe , Pidko Evgeny A. , Filonenko Georgy A.
Published: September 2021

A highly efficient bicarbonate hydrogenation catalyst system based on ppm concentrations of a Ru-PNP pincer complex is presented. It allows converting supersaturated bicarbonate slurries to aqueous formate solutions up to 12 M in molarity.
Aerobic cross-dehydrogenative couplings of N-heteroarenes with toluene derivatives at room temperature
Authors: Wang Qiao-Lin , Huang Huawen , Sun Zhaozhao , Chen Yufeng , Deng Guo-Jun
Published: September 2021

The unique combination of photocatalysis, bromo radical mediation, and aerobic oxidation proved to be the key for successfully achieving the cross-dehydrogenative coupling reaction.
Recent progress in cellulose-based electrospun nanofibers as multifunctional materials
Authors: Zhang Yirong , Zhang Cunzhi , Wang Yixiang
Published: September 2021

The combination of the electrospinning technique and cellulose provides a promising approach to produce nanostructured porous materials with desirable properties, enabling value-added applications in a wide range of fields.
Formic acid and formate salts for chemical vapor deposition of copper on glass substrates at atmospheric pressure
Authors: Mokhtari Omid , Conti Fosca , Saccon Rodolfo , Bhogaraju Sri Krishna , Elger Gordon
Published: September 2021

Deposition of copper on glass slides is obtained at atmospheric pressure using copper microparticles and formic acid or copper formate.
Salicylazine activated plasmonic silver nanoprisms for identification of Fe(ii) and Fe(iii) from aqueous solutions
Authors: Singh Deovrat , Singh Raksha , Kumar Abhay , Singh Anurag Kumar , Yadav Minu , Upadhyay K. K.
Published: September 2021

Silver nanoprisms were synthesized using salicylazine as a reducing and capping agent and were used to identify Fe2+/Fe3+ from a few real samples.
Tailoring the mechanoresponsive release from silica nanocapsules
Authors: Uebel Fabian , Thérien-Aubin Héloïse , Landfester Katharina
Published: September 2021

We designed silica nanocapsules able to encapsulate and release cargo molecules upon the application of a mechanical stress. By tuning the architecture of the nanocapsules, the force required to induce the release was successfully controlled.
[Pd]-Catalyzed para-selective allylation of phenols: access to 4-[(E)-3-aryl/alkylprop-2-enyl]phenols
Authors: Chinnabattigalla Sreenivasulu , Choudhury Aditya , Gedu Satyanarayana
Published: September 2021

We present a highly regioselective [Pd]-catalyzed para-allylation of phenols using simple, inactivated allylic alcohols as allylating coupling partners. The efficacy of the present protocol was demonstrated by the direct synthesis of obtusastyrene and obtustyrene.
Numerical calculation and model experiment of a novel external buoy type wave energy converter for navigation lighted buoys numerical study of a novel wave energy converter
Authors: Huang Shuo , Liu Weiqi , Zhang Chao , Sheng Songwei , You Yage , Wang Zhenpeng , Wen Kaisheng
Published: September 2021

A novel external buoy type wave energy device with hydraulic conversion system used for navigation lighted buoys, named floating external double buoys wave energy device, is put forward and investigated by numerical calculations and model experiments. The hydrodynamic performance of the device under regular waves is numerically calculated based on linear potential flow theory and boundary element method. The generalized modal method is used to solve the hydrodynamic problems of multi‐buoy with hinged constraints. The model experiments are carried out in a 2D wave tank with a depth of 0.9 m. The wave height is set to 1/40 of the wavelength. The influence of wave period and damping loads on the hydrodynamic performance of the device is tested. The results of numerical calculations and model experiments have shown that the appropriate selection of hydraulic damping coefficient is of great significance to improve the capture width ratio of the device, and this device has good capture performance in a certain wave range, and it is expected to effectively solve the problem of continuous power supply for middle and small types of navigation lighted buoys.
Study of Pluto’s atmosphere based on 2020 stellar occultation light curve results
Authors: Poro Atila , Ahangarani Farahani Farzaneh , Bahraminasr Majid , Hadizadeh Maryam , Najafi Kodini Fatemeh , Rezaee Maryam , Seifi Gargari Mahsa
Published: September 2021

On 6 June 2020, Pluto’s stellar occultation was successfully observed at a ground-based observatory in Iran, and Pluto’s atmospheric parameters were investigated. We used an atmospheric model of Pluto, assuming a spherical and transparent pure N2 atmosphere. Using ray-tracing code, the stellar occultation light curve was satisfactorily fit to this model. We found that Pluto’s atmospheric pressure at the reference radius of 1215 km was 6.72 ± 0.48 μbar in June 2020. Our estimated pressure shows a continuation of the pressure increase trend observed since 1988 and does not confirm the rapid pressure decrease tentatively reported in 2019. The pressure evolution is consistent with a seasonal transport model. We conclude that the N2 sublimation process from Sputnik Planitia is continuing. This study’s result is shown on the diagram of the annual evolution of atmospheric pressure.
Regio- and Stereoselective Addition of Brønsted Acids to Yndiamides: Synthesis of N,O,N- and N,S,N-Trisubstituted Ketene Acetals
Authors: Anderson Edward A. , Garry Olivia L. , Mansfield Steven J.
Published: September 2021

Yndiamides, N,N-disubstituted alkynes, are versatile building blocks for the synthesis of nitrogen-containing organic molecules. Unlike ynamides, relatives that are inherently polarized by a single nitrogen substituent, their pseudo-symmetric nature renders regioselective reactions challenging. Here we report investigations into the regio­selective addition of Brønsted acids to non-symmetric yndiamides, a reaction that delivers N,O,N- and N,S,N-trisubstituted ketene acetals with excellent regio- and stereoselectivity.
Innovator Filgrastim versus Generic Filgrastim in Hematopoietic Stem Cell Transplantation Mobilization
Authors: Husian Sadik , Jeyaraman Preethi , Gupta S. K. , Rai Reeta , Pathak Sangeeta , Dayal Nitin , Naithani Rahul
Published: September 2021

Methods This is a retrospective study. G-CSF was administered in the dose of 10 μg/kg subcutaneous as a single dose for 4 days. On day 5, peripheral blood stem cell (PBSC) apheresis was performed using Haemonetics MCS plus or COBE Spectra apheresis machine through a double-lumen central venous catheter. Primary outcome parameters were the total number of CD34+ HSCs/kg of recipient weight mobilized in peripheral blood and the number of days required for neutrophil and platelets engraftment, respectively.

Objective We compared the effectiveness and safety of innovator filgrastim versus generic filgrastim in patients who underwent hematopoietic stem cell transplantation (HSCT).

Results A total of 91 stem cell mobilizations was analyzed. There were 58 normal healthy donors for allogeneic HSCT and 33 patients for autologous HSCT. There was no statistically significant difference among groups in terms of total collected CD34+ cells value (p = 0.609). The mean time to neutrophil engraftment was 13.7 days in the innovator group and 13.2 days in the Grafeel group (p = 0.518). The mean time to platelet engraftment was 16.2 days in the innovator group and 14.8 days in the generic group (p = 0.435). The patient who received generic filgrastim had more febrile episodes during the course of transplantation (p = 0.020).

Conclusion Generic filgrastim was found to be comparable to original filgrastim for peripheral blood stem cell mobilization in normal healthy donors for allogeneic HSCT and patients for autologous HSCT.
A Prospective Study of Taxane-Induced Neuropathy with Breast Cancer: Proper Assessment Tool for Taxane-Induced Neuropathy
Authors: Sohn Eun Hee , Lee Jin Sun , Jung Mi Sook , Kim Je Ryong
Published: September 2021

Background Many chemotherapeutic agents, especially taxanes, can induce peripheral neuropathy.

Aim To evaluate the clinical characteristics of taxane-induced neuropathy (TIN) and determine the proper assessment tool for TIN in patients with breast cancer.

Setting and Design Single-center, observational, prospective study.

Methods and Material Forty-three patients with breast cancer treated with taxanes were prospectively enrolled. The reduced version of the Total Neuropathy Score (TNSr) was performed at baseline and 3 months after enrollment. TIN was diagnosed if the difference between the baseline and 3-month TNSr was greater than 1. In patients with TIN, the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire— Chemotherapy-Induced Peripheral Neuropathy (20-item scale (EORTC-CIPN20) was also assessed 3 months after enrollment.

Results Thirty-seven out of 43 (86.0%) patients were diagnosed with TIN. Sensory symptoms (64.9%) were the most frequent abnormality, followed by autonomic symptoms (54.1%). No patients reported motor symptoms or motor weakness. The TNSr sensory symptom score positively correlated with that of the EORTC-CIPN20. Nerve conduction studies showed reduced nerve conduction velocities and amplitudes after taxane treatment compared to those before chemotherapy in all tested nerves; however, only three (8.1%) patients had sural sensory nerve action potential amplitude outside normal limits.

Conclusions TIN was predominantly sensory with normal nerve conduction studies which is the main feature of small fiber neuropathy. A combination scale comprising of a clinician-based scale and a patient-reported questionnaire and specialized tests for small nerve fibers should be considered as proper assessment tools to evaluate TIN.
International business studies: Are we really so uniquely complex?
Authors: Aguinis Herman , Gabriel Kelly P.
Published: September 2021

Articles in Journal of International Business Studies (JIBS) and elsewhere have argued that international business (IB) is a uniquely complex field. We offer an alternative perspective and evidence that IB is not so uniquely complex compared to organizational behavior, strategic management studies, and entrepreneurship. We argue that viewing IB as uniquely complex is likely a result of what a vast body of social psychology research has uncovered and labeled false uniqueness bias: the tendency for people to believe that they are unique compared to others. We discuss selective accessibility and focalism as underlying psychological mechanisms of this bias. We acknowledge advantages of claiming uniqueness, but argue that it is now more beneficial and realistic to highlight similarities. Doing so will allow IB to import and export theories and methods and thereby make IB borders even more permeable. In turn, increased permeability is likely to lead to further theoretical progress that will benefit IB research, practice, and its positive impact on organizations and society even further. To illustrate advantages of not exaggerating IB’s uniqueness, we use JIBS Decade Award winners as exemplars of studies that are admired and impactful precisely because of their focus on similarities rather than unique complexity.
Conjugation Approaches for Peptide-Mediated Delivery of Oligonucleotides Therapeutics
Authors: Patil Nitin A.
Published: September 2021

Oligonucleotide-based agents are versatile biomolecules that modulate gene expression. The last decade has seen the emergence of oligonucleotide-based tools for biochemical investigations. Importantly, several oligonucleotide-based drugs and vaccines are currently used for various therapeutic applications ranging from anti-inflammatory and anti-viral agents to those used in cardiovascular, ophthalmic, and neuro-muscular disorders. Despite a broad range of applications, achieving efficient oligonucleotide delivery remains a major limitation. A possible solution is to conjugate cell-penetrating peptides with oligonucleotides. This review provides an overview of chemical strategies used to synthesise peptide–oligonucleotide conjugates. The merits and liabilities of these strategies are discussed in the context of synthetic efficiency, and bio-reversible and -irreversible linkages.
Cadmium and arsenic provoke mostly distinct but partly overlapping responses in
Authors: Khan Allah Dad , Khan Muhammad Sayyar , Bangash Sajid Ali Khan , Naeem Kashif , Jalal Abdullah , Tayyab Muhammad
Published: September 2021

Among the toxic heavy metal(loid)s, cadmium (Cd) and arsenic (As) have devastating effects on crop productivity and human health. In plants, mechanisms of detoxification of Cd and As proceed via a glutathione (GSH) dependent common pathway, despite their different modes of toxicity. In this context, the present study aimed to investigate how the common detoxification mechanisms for Cd and As influence the physiological and biochemical responses of seedlings of an important plant used for phytoremediation purposes, Brassica juncea, under Cd and As stress. We demonstrated that Cd and As trigger mostly distinct, but partly overlapping, responses in B. juncea. Exposure of B. juncea seedlings to 100 μM Cd stress for 12 days in a hydroponic system led to a significant reduction in the growth of roots and shoots, and in total chlorophyll content. However, As stress caused a decline in root length only. High-performance liquid chromatography analyses revealed a significant increase in cysteine levels in roots and shoots in response to As stress compared with control and Cd-treated plants. Concomitant elevated sulfur content in response to As stress was observed in roots and shoots. In terms of GSH content, Cd and As triggered similar responses, with a significant decrease in GSH in roots, and non-significant changes in shoots, compared with untreated plants. Inductively coupled plasma-atomic emission spectroscopy revealed that under Cd stress, plants preferentially accumulated zinc (Zn) in the roots compared with iron (Fe) and manganese (Mn). Responses in roots under As and Cd stress were similar with respect to Fe accumulation but opposite in terms of Zn and Mn accumulation. Our data provide valuable insights for design of future strategies for sustainable plant growth on As and Cd polluted soils.
Exploiting the struggle for haem: a novel therapeutic approach against
Authors: Atto Brianna , Gell David , Tristram Stephen
Published: September 2021

Over the past decade, nontypeable Haemophilus influenzae (NTHi) has gained recognition as a major opportunistic pathogen of the respiratory tract that imposes a substantial global burden of disease, owing to a high rate of morbidity and ensuing complications. Further amplifying the global impact of NTHi infections is the increasing spectrum and prevalence of antibiotic resistance, leading to higher rates of treatment failure with first- and second-line antibiotics regimes. The threat of antibiotic resistance was recognised by the World Health Organization in 2017, listing NTHi as a priority pathogen for which new therapies are urgently needed. Despite significant efforts, there are currently no effective vaccine strategies available that can slow the growing burden of NTHi disease. Consequently, alternative preventative or therapeutic approaches that do not rely on antibiotic susceptibility or stable vaccine targets are becoming more attractive. The nutritional dependency for haem at all stages of NTHi pathogenesis exposes a vulnerability that may be exploited for the development of such therapies. This article will discuss the therapeutic potential of strategies that limit NTHi access to this vital nutrient, with particular focus on a novel bacteriotherapeutic approach under development.
‘The awesome power of yeast’ in Alzheimer’s disease research
Authors: Dhakal Sudip
Published: September 2021

The difficulties in performing experimental studies related to diseases of the human brain have fostered a range of disease models from highly expensive and complex animal models to simple, robust, unicellular yeast models. Yeast models have been used in numerous studies to understand Alzheimer’s disease (AD) pathogenesis and to search for drugs targeting AD. Thanks to the conservation of fundamental eukaryotic processes including ageing and the availability of appropriate technological platforms, budding yeast are a simple model eukaryote to assist with understanding human cell biology, offering a platform to study human diseases. This article aims to provide insights from yeast models on the contributions of amyloid beta, a causative agent in AD, and recent research findings on AD chemoprevention.
Neutrophil-specific gain-of-function mutations in Nlrp3 promote development of cryopyrin-associated periodic syndrome
Authors: Stackowicz Julien , Gaudenzio Nicolas , Serhan Nadine , Conde Eva , Godon Ophélie , Marichal Thomas , Starkl Philipp , Balbino Bianca , Roers Axel , Bruhns Pierre , Jönsson Friederike , Moguelet Philippe , Georgin-Lavialle Sophie , Broderick Lori , Hoffman Hal M. , Galli Stephen J. , Reber Laurent L.
Published: September 2021

Gain-of-function mutations in NLRP3 are responsible for a spectrum of autoinflammatory diseases collectively referred to as “cryopyrin-associated periodic syndromes” (CAPS). Treatment of CAPS patients with IL-1–targeted therapies is effective, confirming a central pathogenic role for IL-1β. However, the specific myeloid cell population(s) exhibiting inflammasome activity and sustained IL-1β production in CAPS remains elusive. Previous reports suggested an important role for mast cells (MCs) in this process. Here, we report that, in mice, gain-of-function mutations in Nlrp3 restricted to neutrophils, and to a lesser extent macrophages/dendritic cells, but not MCs, are sufficient to trigger severe CAPS. Furthermore, in patients with clinically established CAPS, we show that skin-infiltrating neutrophils represent a substantial biological source of IL-1β. Together, our data indicate that neutrophils, rather than MCs, can represent the main cellular drivers of CAPS pathology.
Tunable characteristics of porous silicon optical microcavities by energetic N ion beam interactions
Authors: Verma Chandra Prakash , Adnan Mohammad , Srivastava P , Asokan K , Kanjilal D , Vijaya Prakash G
Published: September 2021

The present study demonstrates the tuning of optical characteristics of porous silicon (PSi)-based microcavities by N ion beam interactions. These optical microcavities are prepared by using electrochemical etching of heavily doped p+-type Si. The PSi microcavities were exposed to N ions of 200 keV and 1 MeV at an optimized ion fluence of 1 × 1015 ions cm−2. A significant red-shifting of 32 ∼ 60 nm in the resonance cavity mode was observed due to ion interaction. The experimental results are in good agreement with the transfer matrix simulations. A substantial modification of the PSi microcavity surface states is visualized through Raman and x-ray photoelectron spectroscopy (XPS) techniques. The Raman spectral results show modifications from crystalline Si to nanostructured Si and subsequently to amorphous Si. The XPS indicates the modification of Si–Si and Si–O bonds and the formation of new Si–N bonds, implying the presence of Si3N4. These experimental observations, along with analytical simulations and transfer-matrix method microcavity modeling, conclusively support the realization of cavity tunability and substantial modification in the optical field intensity and photon confinement within the spacer layer of the microcavity. These results suggest that ion beams are the effective tool to produce wider tunable optical properties in microcavities with highly stable designer optical structures suitable for photonic applications.
Determination of uniaxial tensile strength of brittle materials using tubular samples
Authors: Guerrero-Miguel D J , Alvarez-Fernández M I , Prendes-Gero M B , González-Nicieza C
Published: September 2021

Tensile strength of brittle materials is usually obtained through Brazilian tests. It is accepted that failure is initiated at the centre of the sample and that it propagates through the material, creating a tensile failure plane along the vertical diameter or at the majority of it. Then, the tensile stress developed at the centre of the disc is considered as the tensile strength of the material tested. However, the stress state along the vertical diameter is always biaxial, even in the centre of the sample. This implies that the strength measured using such technique is not the uniaxial tensile strength. In this article, the expressions of the stress state supported by a tubular sample subjected to a novel device to determine the tensile strength of brittle materials are described. Besides, it is noticed that the failure plane contains points with the maximum uniaxial tensile strengths so the testing method is adequate to determine the uniaxial tensile strength of brittle materials.
Determination of thermal conductivity variation through Modified Transient Plane Source (MTPS), and its relationship with porosity variation on thermally treated Prada limestone
Authors: Martínez-Ibáñez V , Garrido M E , Hidalgo Signes C , Tomás R
Published: September 2021

In this research, the variation of thermal conductivity with temperature of a limestone and its relationship with porosity is studied. Samples from Prada formation, a lower Cretaceous limestone from the Catalan Pyrenees (Spain), obtained from the Tres Ponts road tunnel were subjected to temperatures of 105, 300, and 600 °C and then cooled at a slow rate by air-cooling to laboratory temperature. Open porosity tests were determined before and after heating to evaluate the porosity increase and the micro-cracks growth. Complementarity, thermal conductivity was measured in the rock samples before and after the application of a thermal treatment by means of C-Therm TCi device, a Modified Transient Plane Source (MTPS). This is a non-invasive, quick, and precise method, when compared with other steady-state laboratory alternatives, widely used to directly determine thermal properties of rock samples. A clear decrease in the thermal conductivity of above 10% was observed for samples heated at 600 °C, probably due to a dramatic increase in porosity. The obtained results could be of great interest for the incorporation of the effect of temperature on rock in numerical models, to evaluate the potential impacts induced by eventual fires developed inside the Tres Ponts tunnel.
Thermal shock-induced physical changes of granitic rocks of a radioactive waste disposal site
Authors: Németh A , Török Á
Published: September 2021

Medium-and low-level radioactive waste is stored in the subsurface galleries of a granitic formation in Southern Hungary. The main lithology is monzogranite. The present study focuses on the thermal behavior and characteristics of intact rocks and thermally exposed specimens. Cylindrical specimens were heated to 250°C, and 500°C in an electric oven in laboratory conditions. Physical properties (density, ultrasonic pulse velocity) and non-destructive strength tests such as Duroskop rebound value were measured on samples kept at 22°C and on samples exposed to heat. The test procedures followed the guidelines given in EN. Tests show that the bulk density was reduced after the 250 °C treatment but slightly increased due to additional heat up to 500 °C. The ultrasonic pulse velocity rapidly decreases with temperature from 22°C to 500°C. The Duroskop rebound values also show a negative correlation with temperature. Color changes are also observed since the grey specimens became increasingly brownish with increasing temperature. The test results demonstrate that with increasing temperature, the tested monzogranite becomes less dense, and micro-cracks reduce the surface strength.
Comparison of strength-based rock brittleness indices with the brittleness index measured via Yagiz’s approaches
Authors: Yermukhanbetov K , Yazitova A , Yagiz S
Published: September 2021

Rock brittleness is one of the most significant properties of rock having a major impact not only on the failure process of intact rock but also on the response of rock mass to rock excavation. In fact, the brittleness is a combination of rock properties including not only the uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS) but also density and porosity of rocks. Due to that, the brittleness should be examined very carefully for any excavation projects, i.e., mechanized excavation, drilling and blasting. The aim of this paper is to compare the strength-based brittleness indices with both the rock brittleness index (BIo), directly obtained via punch penetration test (PPT) and also estimated via Yagiz’s approach (BI1) as a function of strengths and density of rocks. For the aim, database including more than 45 tunnel cases are used to compute common rock brittleness indices (BI2, BI3, BI4), different combination of UCS and BTS. Further, these indices are compared with both BIo and BI1 as well as each other. It is found that the BIo and BI1 have a significant relations (ranging of determination coefficients (r2) from 0.69 to 0.88 with strength-based brittleness indices commonly used in practice. Also, based on findings, several rock brittleness classifications are also revised herein.
Frictional properties of natural and induced fractures in two types of shales
Authors: Bohloli Bahman , Smith Halvard , Sauvin Guillaume , Cerasi Pierre R.
Published: September 2021

This paper presents results of direct shear tests on two types of shales; Rurikfjellet from Svalbard, Arctic Norway and Draupne from Ling Depression, the North Sea. Rurikfjellet formation is part of a caprock system for the proposed CO2storage site at Svalbard. Draupne shale forms the caprock for deep hydrocarbon reservoirs and also the primary seal for Smeaheia, a candidate site for CO2storage in the North Sea. Four specimens from Rurikfjellet and one specimen from Draupne were tested. Results of the tests shows that the peak friction coefficient for fractures in Rurikfjellet specimens varies between 0.26 and 0.29 while the residual friction coefficient ranges from 0.19 to 0.25. For Draupne shale, peak and residual friction coefficients were equal; i.e. 0.25. Simulation of friction coefficient was performed using the Barton-Bandis model and showed relatively good results in the post-peak and residual parts. The results of these tests provide reliable input data to support analytical and numerical models for assessing stability of fractures and faults under various loading conditions.
Determination of the basic friction angle ϕb of joints using the field tilt test: results of various “fast” tests on outcrops
Authors: Jordá-Bordehore L , Alejano L , Tomás R , Loaiza S C , García M T , Galindo R Á , Pérez-Rey I , Riquelme-Guill A , Cano M , Borja-Bernal C P , Medinaceli Torrez R
Published: September 2021

The basic friction angle of rock joints is usually obtained from tilt tests, being the most common the laboratory tilt tests. This test has been standardized according to the ISRM. However, most of the times when calculating the shear strength of discontinuities, reference tables are used to obtain the basic friction value for the lithology under study. These tables omit some lithologies complicating the search of adequate references. An alternative, straightforward and economical way to obtain ϕb
is through the field tilt test, which is carried out by sliding two blocks aside a joint. It is a well-known test, but there are few references to its implementation. In this test, unlike the laboratory tilt test, the samples are not “polished” and it is necessary to evaluate the roughness of the joint and the normal component to the weight of the upper blocks. The idea is to calculate the term of ϕb
from the Barton-Bandis’ equation and include the tilt angle α. Various tilt-test measurements were carried out with field blocks on both sides of the same joint, considering different lithologies (granite, limestone, andesite, dacite, coal and slate) and block sizes, evaluating the ideal ranges of applicability of the test.
Descriptive and quantitative analysis of fracture systems in a carbonate rock mass complex
Authors: Gallas J , Backers T
Published: September 2021

The study area is located in the Franconian Alb in Southern Germany and is an Upper Jurassic, karstified and fractured, regularly bedded carbonate rock mass with thin marl interlayers. Structurally, these deposits are heterogeneous and a classification into structural types is striven for in this study. The structural classification is based on discontinuity and fault characteristics gained from field work. The study area is considered an analogue for Germanys most productive deep geothermal reservoir horizon in the South German Molasse Basin. The aim of the field study is to describe and quantitatively analyse the different structural types, and to optimize the scanline method for a specific geological setting to gain comprehensive information with regard to fracture permeability and rock mass behaviour. The structural types are described in terms of discontinuity orientation and density, rock strength, and fault characteristics. To optimize the scanline method for the field study additional discontinuity attributes were added. One of these accessory attributes, the existence of discontinuity lags, will be discussed. It occurs when vertical and sub-vertical fractures cross sedimentary layers and continue with a small horizontal displacement in the next sedimentary layer. The results of this study are used to improve derived fracture networks with respect to thermo-hydro-mechanical models in the geothermal sector. Following article discusses the first results of the above-mentioned field study.
Fracture density analysis at Stromboli Volcano, Italy: implications to flank stability
Authors: Alcock T , Vinciguerra S , Benson P , Vagnon F
Published: September 2021

Stromboli volcano has experienced four sector collapses over the past 13,000 years, resulting in the formation of the Sciara del Fuoco (SDF); a horseshoe-shaped flank collapse scarp where episodes of instability are continuously observed and recorded. A NE / SW striking rift zone across the SDF and the western sector of the island is inferred to be a potential weakness zone for further instability episodes. This study reports new data of fracture density using remote sensing imagery, across within and outside the rift zone, to identify areas of damage that could reduce the edifice strength and promote fracturing. Pleiades satellite data of 0.5 m resolution was processed to highlight 23635 distinct linear features, determine fracture density across the island, and identify key areas of macro-scale weakness on the volcano. These data suggest that the SW sector of the island, including the summit area and the slopes of SDF, have an average fracture density between 1.18 – 2.73 × 10−5m−2in contrast to the rest of the volcano that has an average fracture density of 4.56 × 10−6m−2. Analysis was also conducted on the orientation of fracture strikes across the volcanic edifice by analysing fracture data specifically associated with areas of intrusions and fissures: the NW / SE rift zone and the SDF. Preliminary results show that the average fracture strike ranged from between 030 – 047 NE/SW and thus broadly parallel to the inferred rift axis.
Acoustic emission and digital image correlation for damage evolution in brittle rocks under time-dependent tensile loading
Authors: Moradian Omid , Wu Rui , Li Ying , Leith Kerry , Loew Simon
Published: September 2021

Time-dependent rock deformation is considered to precede dynamic failure in many rock-engineering projects and natural geohazards. In order to understand long-term performance of brittle rocks, we gather mechanical load, strain, acoustic emission (AE) and digital image correlation (DIC) data to describe the evolution of damage and cracking in response to tensile loading during multi-stage relaxation experiments on inverted single edge notch bending (iSENB) specimens. The source locations of the AEs correspond to a process zone ahead and around the notch indicating the evolution of the microcracks. The results showed that the cracks first start aseismicaly under subcritical growth until 10mm from the tip of the notch and then they grow seismically by showing seismic signals in the form of acoustic emissions. It was observed that the process zone obtained by DIC is smaller than the cloud of the AE locations. This can be partially because DIC only shows surface deformation and partially because of the errors associated with the AE source locations such as ignoring anisotropic velocity, sampling rate, sensor locations, etc. Moment tensor analyses of the AE signals showed that both tensile and shear cracks are involved in the micro-scale although in the macroscopic scale the damage process is mostly considered as tensile. The results showed that microcracks start as tensile, and then continue as shear, especially at the end of the crack where the specimen experiences compression loading.
Discrete Element Modelling of Rock Creep in Deep Tunnels using Rate Process Theory
Authors: Gutiérrez-Ch J G , Senent S , Zeng P , Jimenez R
Published: September 2021

Rock creep behaviour is a key aspect of many engineering projects, such as deep tunnels in which squeezing problems could occur. Many theories have been published in the literature to reproduce rock creep behaviour; however, most of them are not able to capture the last phase of creep (i.e., tertiary creep, or the accelerating strains that occur prior to failure). In this work, the Distinct-Element Method (DEM) approach is employed, in conjunction with Rate Process Theory (RPT), to simulate the effect of rock creep in deep tunnels. To do that, the DEM models are constructed using particles, whose interactions are simulated with a hybrid mixture of the Flat Joint Contact Model (FJCM) and the Linear Model (LM) contact models; the RPT is implemented into DEM models using a Visual C++ function. Results show that the DEM plus RPT combination can suitably reproduce the tunnel convergences due to rock creep.
Geomechanical substantiation of the Oleniy Ruchey deposit underground mining in a protective pillar of the Niorkpakhk open pit
Authors: Zemtsovskii A V , Semenova I E
Published: September 2021

The location of significant volumes of the lower level reserves close to an open pit which produces the adjacent Niorkpakhk deposit considerably complicates underground mining of the Oleniy Ruchey rockburst-hazardous deposit. The progress of underground excavations into the under-pit space is permitted if the undermined rock thickness and open pit walls remain stable. 3D numerical studies of stress-strain state have indicated particularities in deformation such as increase in undermined thickness stability under high tectonic stresses. The parameters of safe mining of temporary inactive reserves were scientifically substantiated. The boundaries of maximal development of underground mining were determined. The stability of overlying rocks and open pit walls is maintained by forming an advance of overlying sublevels relative underlying ones under 45° angle and providing the monitoring for the undermined rock mass. The mining method in a protective pillar the authors propose allows increasing reserves of the first mining stage by 76.9% and avoiding decrease in production volumes when mining operations terminate.
The integrated usage of ground-based and satellite SAR, along with 3D structural modelling in Titania: creating a link between short and long - term slope stability hazard management
Authors: Botsialas K , Ravde V , Falomi A , Meloni F , Boldrini N , Bellotti F , Leoni L , Coli N
Published: September 2021

Mining is a high risk business and for every modern mining industry, the main aim of its open pit design is to create walls that will be stable for the life of the open pit, which in some cases may extend beyond the closure. As a result, any kind of instability should be manageable and if possible, it should not develop to instabilities. This paper focuses on 300.000 tons instability that began in 2008 and continues until today in Titania. The hazard associated with this instability was a constant threat for the continuation of the production and the safety of people and machinery. In order to manage the hazard in short- and long-term, it was evident that data from different sources should be combined and analyzed. Data from ground-based and satellite SAR were used to delineate the unstable area through a period of 10 years. At the same time advanced implicit modelling techniques were used to integrate borehole and surface structural data in a 3D structural model. This 2 stage workflow, led to a set of preventive and remedial measures that allowed the continuation of the production the last ten years and will ensure the continuation of the production for, at least, other ten years.
Considerations on the deformation of Ridracoli dam foundation based on the analysis of monitoring data
Authors: Lusini E , Boldini D , Graziani A
Published: September 2021

The behaviour of the Ridracoli arch-gravity dam in the 2002-2020 operation years has been analysed, by applying “statistical” models of increasing complexity to the time series of pendulum and long-base extensometer measurements. The modelling approach has proved robust. A satisfactory estimate of the reservoir load, thermal and irreversible drift components has been obtained for most of the instruments. As expected, the influence of temperature is lower for the instruments deeply embedded in the rock mass. The deformations recorded on the left and right bank of the dam have shown a minor influence of the anisotropic proprieties of the rock mass, well characterized by the mechanical tests performed at the time of dam construction.
Application of SBAS-DInSAR to monitoring landslides along the northern Black Sea coast in Bulgaria
Authors: Yamaguchi M , Yastika P E , Shimizu N , Milev N , Vrkljan I
Published: September 2021

The Black Sea coast of Bulgaria is well known as an active landslide area across which various landslides extend. Monitoring the real behavior of landslides has not often been conducted due to technical difficulties and cost issues, although it is essential to reveal the mechanism of these landslides and to solve the problems they cause. In this paper, SBAS-DInSAR is applied to monitor the landslide displacements along the northern Black Sea coast. The results are compared with the field observation results described in the official annual reports of landslides issued in Bulgaria and other published papers. It is found that the SBAS-DInSAR results show a good agreement with the actual behavior and verify its applicability for monitoring landslides in extensive areas along the northern Black Sea coast.
Review of U.S. subsidence monitoring using conventional and satellite based methods
Authors: Maleki H , McKenzie J
Published: September 2021

Tracking of surface deformations is typically achieved using periodic measurements of both vertical and horizontal deformations using conventional, Ground Positioning Satellite (GPS), and or photographic techniques. Within the last decade, satellite based methods have also found limited applications over some underground coal mines and commercial applications for open pit mines. In this paper, the authors will review the subsidence monitoring over one of the Colorado operations utilizing precise GPS measurements. This case study will address geologic setting, vertical and horizontal displacements, the influence of topography and gate pillar designs on surface subsidence and fracturing, upon longwall extraction of the Upper D Seam. In addition, we will review the potential use of satellite based, remote sensing methods. InSAR technologies are finding new interest in the U.S. mining industry for (1) investigating the utility of InSAR in discriminating different types of seismic events including underground explosions, natural earthquakes and mine collapses (2) tracking surface subsidence for satisfying permitting requirements and (3) potential use in the area of mine safety. The combination of satellite InSAR imaging and GPS measurements is suggested for enhancing the quality of ground movement analysis including assessment of horizontal deformations and effects on surface resources. Satellite data availability, and the improvements in interpretation and processing tools, are very promising.
A new parameter for TBM data analysis based on the experience of the Brenner Base Tunnel excavation
Authors: Heikal G , Erharter G H , Marcher T
Published: September 2021

Tunnel boring machine (TBM) operational data can be seen as a function of three main influences: the machinery of the TBM itself, the way the TBM is operated, and the excavated rockmass. Whereas the processing of TBM data must be done by computer-aided methods, the interpretation is typically done visually and is highly dependent on the user’s prior experience. One way is to inspect the raw data itself, and another is to inspect computed parameters (specific penetration, specific energy or torque ratio). Either way, the goal is to find distinctive patterns that indicate changes in the rock mass conditions, and therefore it is crucial to find parameters that bear as much information as possible. The goal of this paper is to introduce the new parameter “theoretical advance force” (FNtheo
) that was developed in the course of systematic analysis of TBM operational data from the exploratory tunnel Ahrental Pfons (part of the Brenner Base tunnel project). FNtheo
is back-calculated from the measured cutterhead torque and the measured penetration. The theoretical advance force shows very promising results with the data at hand, yielding more pronounced and well-defined patterns that correlate better with the encountered rockmass conditions than several other common parameters.
Spalling prediction by distortion strain energy
Authors: Alber M , Bartmann K
Published: September 2021

Spalling can be a serious threat to underground excavation works in hard, good quality rock masses at great depth. Spalling endangers drill & blast advance or TBM drives with severe damage of tunnel walls or the face. In mining the concern is about spalling at pillars and at the face. Research on spalling is mainly associated with the definition of Crack Initiation (CI) and Crack Damage (CD) stresses and the definition of the S-shaped spalling strength envelope. Particularly CI stress at low confining stress (σcc/σ3 < 0.05 and σ1/σ3 < 10) is important for defining spalling around an underground excavation in hard rock. We summarize 59 UCS tests and 197 triaxial tests (σ3 < 2.5 MPa) with sedimentary, magmatic, and metamorphic rocks, respectively, and defined robust CI and CD stresses. In this paper, we focus on the distortional strain energy at CI and CD stresses. From a rock mechanical point of view, crack initiation and crack damage are associated with stress (or strain) deviation. Analyses of the very well instrumented tests shows that for any rock type (saturated and dry) crack initiation (CI) occurs at 20% and crack damage (CD) at 75% of the distortion strain energy at failure. This approach was tested at the well-known case of spalling at the test tunnel in the AECL Underground Research Laboratory. Mechanical properties for the Lac du Bonnet granite were used to estimate distortional energy at CI and to model breakout depth and shape.
Rockfall hazard assessment of the Monte Gallo Oriented Nature Reserve area (Southern Italy)
Authors: Cafiso F , Cappadonia C , Ferraro R , Martinello C
Published: September 2021

The Monte Gallo area is a carbonate relief that develops a significant nature reserve and highly attracts tourism to the urbanized area of the City of Palermo (Southern Italy). The slopes are affected by several rockfall events, which have also caused death, injuries, material damage, and a strong social and economic impact. Here, a detailed geological and geotechnical study to assess the rockfall hazard relating to two sectors of the mount has been carried out. The hazard assessment at the slope scale was performed based on geological, geomorphological, geomechanical, and seismic analysis. Using both analytical and empirical methods and by means of different software, the reconstruction of the propagation areas for the eastern sector of the Mount was possible. Results were used to better understand the overall structure, characterize the rockfall source areas’ kinematics, and recognize the basic failure mechanisms. The obtained runout areas were compared with each other and with those of previous studies conducted in a neighboring area, as well as with the corresponding hazard area maps of the official cartography, which is being updated. It is expected to be supplemented with maps derived from empirical models.