Standard Process Research Articles

Seismic imaging of deep‐seated gold deposit and host rocks through a reappraisal of legacy seismic data in the Fochville mining area, South Africa

AbstractReappraisal of legacy reflection seismic data has shown to deliver value in mineral exploration, particularly in brownfield settings. In this work, we demonstrate how the reappraisal and processing of legacy reflection seismic data can be advantageous in the mineral exploration industry. We use today's standard seismic processing tools to improve the imaging of deep and complex geological structures that host mineral deposits. The recovered and processed 25.3 km long legacy seismic profile in this study was acquired in 1983 by the Gold Division of Anglo‐American as part of the Witwatersrand Gold Fields exploration program. This study aims to improve the imaging of the Ventersdorp Contact Reef gold‐bearing horizon (termed reef), a world‐class gold deposit (2 m thick) situated at depths between ∼2400 and ∼4100 m below the ground surface near South Deep Gold Mine in Fochville, South Africa. The final processing results from the pre‐stack time and phase‐shift migration approaches clearly reveal a dipping reflection associated with the gold‐bearing horizon and major steeply dipping faults that crosscut and displace the deposit. The final results are integrated with borehole information, 1D synthetic modelling and aeromagnetic data to constrain the structural interpretation. In particular, 1D synthetic simulation and borehole data constrain the depth position of the gold deposit. The magnetic data provides additional constraints on the complex faulted blocks of the host rocks such as the intrusions that may have a direct impact on ore resources and evaluation. The mining companies, such as South Deep Gold Mine, operating closer to the seismic profiles can use this new structural information to update the current geological models and improve future mine planning and designs, thus providing some insight into the prospectivity of unmined ground.

Formal Security Analysis of the OpenID FAPI 2.0 Family of Protocols: Accompanying a Standardization Process

FAPI 2.0 is a suite of Web protocols developed by the OpenID Foundation’s FAPI Working Group (FAPI WG) for third-party data sharing and digital identity in high-risk environments. Even though the specifications are not completely finished, several important entities have started to adopt the FAPI 2.0 protocols, including Norway’s national HelseID, Australia’s Consumer Data Standards, as well as private companies like Authlete and Australia-based connectID; the predecessor FAPI 1.0 is in widespread use with millions of users. The FAPI WG asked us to accompany the standardization of the FAPI 2.0 protocols with a formal security analysis to proactively identify vulnerabilities before widespread deployment and to provide formal security guarantees for the standards. In this paper, we report on our analysis and findings. Our analysis is based on a detailed model of the Web infrastructure, the so-called Web Infrastructure Model (WIM), which we extend to be able to carry out our analysis of the FAPI 2.0 protocols including important extensions like FAPI-CIBA. Based on the (extended) WIM and formalizations of the security goals and attacker model laid out in the FAPI 2.0 specifications, we provide a formal model of the protocols and carry out a formal security analysis, revealing several attacks. We have worked with the FAPI WG to fix the protocols, resulting in several amendments to the specifications. With these changes in place, we have adjusted our protocol model and formally proved that the security properties hold true under the strong attacker model defined by the FAPI WG.

Paving the Way for SQIsign: Toward Efficient Deployment on 32-bit Embedded Devices

The threat of quantum computing has spurred research into post-quantum cryptography. SQIsign, a candidate submitted to the standardization process of the National Institute of Standards and Technology, is emerging as a promising isogeny-based signature scheme. This work aimed to enhance SQIsign’s practical deployment by optimizing its low-level arithmetic operations. Through hierarchical decomposition and performance profiling, we identified the ideal-to-isogeny translation, primarily involving elliptic curve operations, as the main bottleneck. We developed efficient 32-bit finite field arithmetic for elliptic curves, such as basic operations, like addition with carry, subtraction with borrow, and conditional move. We then implemented arithmetic operations in the Montgomery domain, and extended these to quadratic field extensions. Our implementation offers improved compatibility with 32-bit architectures and enables more fine-grained SIMD acceleration. Performance evaluations demonstrated the practicality in low-level operations. Our work has potential in easing the development of SQIsign in practice, making SQIsign more efficient and practical for real-world post-quantum cryptographic applications.

Development and Comparison of Model-Based and Data-Driven Approaches for the Prediction of the Mechanical Properties of Lattice Structures

AbstractLattice structures have great potential for several application fields ranging from medical and tissue engineering to aeronautical one. Their development is further speeded up by the continuing advances in additive manufacturing technologies that allow to overcome issues typical of standard processes and to propose tailored designs. However, the design of lattice structures is still challenging since their properties are considerably affected by numerous factors. The present paper aims to propose, discuss, and compare various modeling approaches to describe, understand, and predict the correlations between the mechanical properties and the void volume fraction of different types of lattice structures fabricated by fused deposition modeling 3D printing. Particularly, four approaches are proposed: (i) a simplified analytical model; (ii) a semi-empirical model combining analytical equations with experimental correction factors; (iii) an artificial neural network trained on experimental data; (iv) numerical simulations by finite element analyses. The comparison among the various approaches, and with experimental data, allows to identify the performances, advantages, and disadvantages of each approach, thus giving important guidelines for choosing the right design methodology based on the needs and available data.

A Modified Bleaching Method for Multiplex Immunofluorescence Staining of FFPE Tissue Sections.

Multiplex immunofluorescence (mIF) staining plays an important role in profiling biomarkers and allows investigation of co-relationships between multiple biomarkers in the same tissue section. The Cell DIVE mIF platform (Leica Microsystems) employs an alkaline solution of hydrogen peroxide as a fluorophore inactivation reagent in the sequential staining, imaging, and bleaching protocol for use on FFPE sections. Suboptimal bleaching efficiency, degradation of tissue structure, and loss of antigen immunogenicity occasionally are encountered with the standard bleaching process. To overcome these impediments, we adopted a modified photochemical bleaching method, which utilizes an intense LED light exposure concurrent with the application of hydrogen peroxide. Repeated stain/bleach rounds with different antibodies were performed on breast tissue and other tissue sections. Residual signal after conventional bleaching and the modified technique were compared and tissue integrity and antigen immunogenicity were assessed. The modified technique effectively eliminates fluorescence signal from previous staining rounds and produces consistent results for multiple rounds of staining and imaging. With the modified method, photochemical treatments did not destroy tissue sub-cellular contents, and the tissue antigenicity was well preserved during the entire mIF process. Overall processing time was reduced from 36 to 30 hours in an mIF procedure with 8 rounds. With the conventional method, tissue quality was highly degraded after 8 rounds. The new technique allows reduced turn-around time, provides reliable fluorophore removal in mIF with excellent maintenance of tissue integrity, facilitating studies of the co-localization of multiple biomarkers in tissues of interest.

Establishment of mouse alveolar macrophage extraction standard and its application in the evaluation of efficacy in lung metastasis of colorectal cancer

Introduction: Alveolar macrophages (AM) are involved in the development and progression of a variety of lung diseases. It is of great significance to explore the pathogenesis of diseases and evaluate the efficacy of drugs. However, there is no standard process for extracting primary AM. Nitidine chloride is an alkaloid extracted from Zanthoxylum nitidum (Roxb.) DC., which has an anti-tumour pharmacological effect. However, there is no evidence that nitidine chloride has a direct effect on CRC cell lung metastasis. The purpose of this study was to establish a standard for the extraction of primary AM from mice and to investigate the pharmacodynamics of nitidine chloride in mice with lung metastases to colorectal cancer. Methods: The standard for the extraction of mouse primary AM by lavage was established. Western blot and PCR were used to detect the regulatory mechanism of nitidine chloride in the treatment of lung metastasis in mice by macrophage phenotype and glycolysis level. Results: The results showed that sufficient quantity and quality of primary AM could be obtained by optimising extraction steps, and AM obtained by this method could accurately reflect disease progression. At the same time, nitidine chloride can effectively reduce colorectal cancer lung metastasis in mice. From the mechanism, nitidine chloride can inhibit the expression of M2 macrophage markers and the levels of mRNA and proteins of the glycolysis-limiting enzyme. Conclusions: Our results show that primary AM that accurately reflect disease and assess pharmacological effects can be obtained using our established criteria. The inhibitory effect of nitidine chloride on colorectal cancer lung metastasis may be attributed to its regulation of macrophage phenotype and glycolysis.

Finding Practical Parameters for Isogeny-based Cryptography

Isogeny-based schemes often come with special requirements on the field of definition of the involved elliptic curves. For instance, the efficiency of SQIsign, a promising candidate in the NIST signature standardisation process, requires a large power of two and a large smooth integer T to divide p 2 − 1 for its prime parameter p . We present two new methods that combine previous techniques for finding suitable primes: sieve-and-boost and XGCD-and-boost. We use these methods to find primes for the NIST submission of SQIsign. Furthermore, we show that our methods are flexible and can be adapted to find suitable parameters for other isogeny-based schemes such as AprèsSQI or POKE. For all three schemes, the parameters we present offer the best performance among all parameters proposed in the literature.

Reactions of Tetracyanoethylene with Aliphatic and Aromatic Amines and Hydrazines and Chemical Transformations of Tetracyanoethylene Derivatives

The significant synthetic potential and reactivity of tetracyanoethylene (TCNE) have captured the interest of numerous chemical communities. One of the most promising, readily achievable, yet least explored pathways for the reactivity of TCNE involves its interaction with arylamines. Typically, the reaction proceeds via tricyanovinylation (TCV); however, deviations from the standard chemical process have been observed in some instances. These include the formation of heterocyclic structures through tricyanovinyl intermediates, aliphatic dicarbonitriles through the cleavage of the C–C bond of a tetracyanoethyl substituent, complexation, and various pericyclic reactions. Therefore, the objective of this study is to review the diverse modes of interaction of TCNE with aromatic nitrogen-containing compounds and to focus the attention of the chemical community on the synthetic capabilities of this reagent, as well as the various biological and optical activities of the structures synthesized based on TCNE.

Techno-economic analysis and optimisation of Piperazine-based Post-combustion carbon capture and CO2 compression process for large-scale biomass-fired power plants through simulation

This study aims to investigate a cost-effective and energy-efficient amine-based post-combustion carbon capture (PCC) process for large-scale supercritical biomass-fired power plants (SC BFPP). Thus, we have quantified the energy and economic performance of the PCC process with different configurations and solvents. Three process configurations which included the standard configuration, the absorber intercooler (AIC) with the advanced flash stripper (AFS) and the AIC, AFS and side stream extraction (SSE) were simulated in Aspen Plus® V11 using 30 wt% and 40 wt% piperazine (PZ) as solvent. In addition to this, CO2 compression trains using the heat pump (HP) and supercritical CO2 cycle (s-CO2) were also simulated. Sensitivity analysis of the PCC process was carried out to investigate the impact of important parameters on the energy performance of the process. Furthermore, energy analysis shows that a minimum energy consumption of 2.78 GJ/tCO2 was achieved with the PCC process using 40 wt% PZ, a combination of the AIC, AFS and SSE for capture and s-CO2 for compression. This achieved a significant energy saving of 1.01 GJ/tCO2 compared with the standard PCC process using 30 wt% monoethanolamine that is used as the benchmark in this study. The economic analysis results showed that the minimum CO2 capture cost of 55.70 $/tCO2 was achieved using the AIC-AFS-SSE-sCO2 configuration and 40 wt% PZ as solvent. This represents a 19.5 % reduction in cost compared with the standard 40 wt% PZ process with a cost of 69.18 $/tCO2. The optimisation of the PZ-based PCC process was carried out to determine the optimal solvent concentration with the minimum carbon capture cost. It was found that the optimal PZ concentration for the PCC process based on standard and AFS configurations were 37.5 wt% and 32.5 wt%, respectively. The optimisation of the stripper pressure for the minimum carbon capture cost was conducted. As a result, compared with the standard PCC process using 40 wt% PZ, the energy consumption and CO2 capture cost of the optimised process at the suggested pressure of 7 bar were reduced by 41.6 % and 32.4 %, respectively.

On the Effect of Cooling Parameters on Solidification Structure in NdFeB Alloys

The elaboration of suitable NdFeB‐based permanent magnets is essential for high‐performance electrical machines in a number of applications. In this respect, the understanding of the relationship between heat transfer phenomena and the final solidified microstructure is the key to the control of the grain size and the improvement of the magnetic properties. The problem is even more acute with the emergence of new manufacturing processes, such as the laser powder bed fusion, where the cooling rates are much higher than those encountered in the standard strip casting process and where the microstructure can be considered as fixed from the fabrication step. The objective of the present work is to identify correlations between interstructural spacings in the solidified alloys and cooling conditions. This study is based on a methodology coupling experimental and numerical simulation approaches featuring three solidification processes: strip casting, arc melting, and laser fusion. The obtained results cover more than four orders of magnitude in terms of cooling rates R and allow to propose a reliable empirical relationship between the interstructural spacing λ and R of the form λ [μm] = 83 R [K s−1]−0.36. This relation can thus be used to estimate cooling rates from metallographic observations.

Acoustic insights into the corn extrusion process for enhanced quality control

In industrial extrusion processes, a solid material is pressed through a die to obtain products of the desired shape and dimension. Fluctuations in the process parameters have a significant impact on the product quality. In food extrusion, the expansion noise at the die can serve as an indicator of the stability of the process. This study employs microphones to characterize the corn extrusion process, focusing on correlating acoustic emissions with predefined process parameters such as feed intake and water content. Experimental data from laboratory and industrial settings reveal distinct domain shifts, yet consistent findings confirm the distinguishability of various extrusion process parameters by analyzing acoustic emissions. Employing machine learning models, including support vector machines and convolutional neural networks, in conjunction with audio features such as log Mel spectrograms, yields promising accuracies above 90\% in discriminating between standard and non-standard process parameters. The proposed acoustic quality control approach has the potential to enhance the stability of extrusion processes and contributes to the development of automated monitoring systems in the field of food extrusion. This ensures consistent quality and reduced waste, ultimately leading to significant cost savings in production.

Tertiary-Amine-Functional Poly(arylene ether)s for Acid-Gas Separations.

Competitive sorption enables the emergent phenomenon of enhanced CO2-based selectivities for gas separation membranes when using microporous polymers with primary amines. However, strong secondary forces in these polymers through hydrogen bonding results in low solvent solubility, precluding standard solution processing approaches to form these polymers into membrane films. Herein, we circumvent these manufacturing constraints while maintaining competitive-sorption enhancements by synthesizing eight representative microporous poly(arylene ether)s (PAEs) with tertiary amines. High-pressure H2S, CO2, and CH4 sorption isotherms were collected for these samples to demonstrate enhanced affinity for acid gases relative to the unfunctional control polymer. Although competitive sorption was observed for all samples, improvements were less pronounced than for primary-amine-functional analogs. For H2S-based separations, the benefits of competitive sorption offset decreases in selectivity due to plasticization. This detailed study helps to elucidate the role of tertiary amines for acid gas separations in solution-processable microporous PAEs.

Borel control and efficient numerical techniques to solve the Allen–Cahn equation governed by temporal multiplicative noise

In this manuscript, we investigate a stochastic version of the Allen–Cahn equation, which is a nonlinear partial differential equation from mathematical physics. The stochastic model considers temporal multiplicative noise in the form of the derivative of the standard Wiener process. The existence and the uniqueness of solutions for this stochastic model is established rigorously using the theory of distributions. As a corollary from these analytical results, some a priori optimal estimates for the solutions of this model are constructed. In this work, we develop reliable numerical schemes which possess similar features as those of the solutions for the analytical model. Moreover, we establish mathematically the von Neumann stability and the consistency for the schemes proposed in this paper. Both the analytical and numerical results derived in this work are computationally verified through some simulations.

Dancing to the same tune? EU and US approaches to standards setting in the global digital sector

ABSTRACT As both the European Union (EU) and the United States (US) construct their approaches to governing the digital economy in a global context, the role and influence of international organisations are being questioned. Specifically, the EU, traditionally a champion of multilateral regimes, has embarked on a strategy that tends toward a ‘digital sovereignty’ approach. However, the EU’s sovereigntist approach relies upon the power of multilateral regimes to ensure ‘managed interdependence’. This article focuses on the differences between the EU and the US regarding global standardisation processes and bodies. It argues that across the Atlantic, there is political agreement on how to manage standards development, but that policies to achieve this often diverge. This article focuses on some of the efforts of the EU-US Trade and Technology Council working group on standardization to show how this agreement on politics, but not policies, has emerged.

Silicon nitride shadowed selective area growth of low defect density vertical GaN mesas via plasma-assisted molecular beam epitaxy

Ion bombardment during inductively coupled plasma reactive-ion etching and ion-implantation introduces irreparable crystalline damage to gallium nitride (GaN) power devices, leading to early breakdown and high leakage current. To circumvent this, a bi-layer selective area growth mask was engineered to grow up to 3.0 µm thick epitaxy of GaN using plasma-assisted molecular beam epitaxy as an ion-damage-free alternative to standard epitaxial processing routes. The masks and regrown architectures are characterized via SEM, conductive-atomic force microscopy (AFM), x-ray photo electron spectroscopy, Raman, and cathodoluminescence. Mask deposition conditions were varied to modulate and minimize the stress induced during thermal cycling. The resulting mesas exhibit low leakage, attributed to naturally terminated sidewalls as measured by an innovative perpendicular AFM measurement of the regrown sidewall. The regrown sidewall exhibited RMS (root mean square) roughness of 1.50 (±0.34) nm and defect density of 1.36 × 106 (±1.11 × 106) cm−2. This work provides a method to eliminate defect-inducing steps from GaN vertical epitaxial processing and stands to enhance GaN as a material platform for high-efficiency power devices.

Micro-nanojauges design to monitor surface mechanical state during high temperature oxidation of metals with application to 17-4PH stainless steel

Determination of mechanical state of thermal oxide growing during high temperature oxidation is a challenge. Fabrication of nanogauges for monitoring during high temperature oxidation was presently investigated up to 1000 °C. Several materials were tested in terms of mechanical behaviour and maximum working temperature for gauges used as markers during thermal loading under air. The experimental determination of the optimized gauges material for high temperature oxidation was validated. SiO2 offers particularly interesting features for gauges to determine the mechanical state of metal/oxide system. In this article, a special attention has also been paid to two nano-fabrication processes, as well as their limits. The standard electron beam lithography process is well suited to build gauges for oxidation applications, and can be improved by use of reactive ion etching process. The gauges can eventually reach several micrometers height such that the oxidation layer does not cover the gauges during thermal loading for relevant monitoring at short oxidation times. To illustrate, an application to a 17-4PH stainless steel oxidized at 480 °C is proposed and stress kinetics are deduced and related to an advanced thermomechano-chemical model, as well as identification of the numerical values of different thermomechano-chemical parameters associated to mechanisms of growth or relaxation.

Terahertz photonic crystal fiber-based edible oil sensor: Performance evaluation and identification

This model introduced an innovative hollow-core optical waveguide with an octagonal core, specifically designed for rapid detection of various food oil contaminations is founded on the principles of Photonic Crystal Fiber (PCF). By analyzing the refractive index (RI) variations between pure and contaminated oil, we evaluate other essential optical parameters. The characteristics inherent to the suggested food oil sensor are examined using COMSOL Multiphysics v6.1, employing the Finite Element Method (FEM). Highly precise mesh components are included to provide optimal simulation accuracy. The outcomes from the suggested sensor model demonstrate exceptionally strong relative sensitivity of 98.52 % for castor oil, 98.46 % for sunflower oil, 98.41 % for mustard oil, 98.32 % for olive oil, and 98.03 % for coconut oil, all measured at 2 THz. Additionally, the simulation shows a very low confinement loss of 2.37 × 10−12 cm-1, a numerical aperture of 0.242, effective area of 1.1459 × 10–7 m², and effective material loss of 0.0038 cm-1 for castor oil under optimal structural circumstances. The straightforward design of the PCF in the sensor indicates that it can be implemented with ease, given these standard performance indicators. Therefore, it is anticipated that this sensor will open improved avenues for detection and identification of several distinct food oil contaminations. It can be produced using standard fabrication processes.

Establishing Triage Competencies and Verification Processes: A Survey Study

IntroductionAlthough the ED triage function is a critical means of ensuring patient safety, core competencies for ED triage are not well defined in the literature. The purpose of the study was to identify and validate emergency triage nursing competencies and to develop a competency verification process. MethodsA sample of 1181 emergency nurses evenly divided between roles with oversight of triage training and competency assessment (manager-level and staff nurses performing triage) completed an online survey evaluating competency elements that comprised the following in terms of frequency and importance, training modalities, and evaluation methods: expert assessment, clinical judgment, management of medical resources, communication, and timely decisions. ResultsBoth manager-level and triage nurses agreed on the importance of the identified competencies. Gaps in training and evaluation were reported by both staff nurses and manager-level nurses. Triage nurses reported less training offered and less competency evaluation compared with manager-level nurses. Triage nurses reported performing all competencies more frequently and at higher level of competency than manager-level nurses reporting on triage nurse performance. DiscussionThis study provides both a standard set of triage competencies and a method by which to evaluate them. Managers and educators might consider this standard to establish initial triage role competency and periodic competency assessment per institutional guidelines. The gap in perceived education and evaluation suggests that standard education and evaluation processes be adopted across emergency departments.

E-Waste Management Practices Through the Eyes of Responsible Departments at Malaysian Public Universities

Electronic and electrical waste (E-waste) has been identified as the fastest-growing waste stream in the world. In Malaysia, forecasts indicate that it will soon reach 24.5 million units of e-waste by the year 2025. Today, higher learning institutions also contribute to the rapidly growing threat of e-waste. Besides mobile phones, the usage of Information and Communication Technology (ICT) equipment at universities keeps increasing and contributes to the increased quantity of e-waste, while the handling and disposal methods of e-waste still need to be improved. The purpose of this paper is to examine the current e-waste management system as well as to investigate the critical challenges constraining e-waste management at public universities in Malaysia. By using a qualitative approach, a number of interview sessions have been conducted with the responsible departments at six established public universities in Malaysia. It has been found that currently only e-waste generated from used electric and electronic equipment (EEE) which have been declared as university assets are being managed by the responsible departments at the six universities. All six universities are using the standard process of handling their e-waste since every single process needs to comply with the requirements of the Ministry of Finance (MOF). This remains the main constraint to flexibility or improvement of the current system. The universities are also facing some challenges, among others, lack of awareness and knowledge on how to properly handle e-waste among university citizens, no clear sustainable policy at the university, lack of facilities within the university compound to support the proper practice of e-waste disposal as well as lack of education and related training provided to the campus citizens. This paper also provides some recommendations for the improvement of e-waste management towards sustainability and offers an agenda for future research.

Al(Si)/Al2O3 and NiAl(Si)/Al2O3 co-continuous composites obtained by low temperature Reactive Metal Penetration of dense silica preforms.

Interpenetrating network Al(Si)/Al2O3 composites, obtained by a reactive metal penetration process, where pure aluminum metal reacts with a dense amorphous silica preform, are an interesting class of metal/ceramic composites, with two continuous networks of metal (Al-Si alloy) and ceramic (Al2O3). These composites have high stiffness and hardness, while retaining acceptable toughness and good thermal and electrical conductivity, and can be used in wear or thermal management applications. A second infiltration step with nickel allows to substitute the Al(Si) alloy with an intermetallic, obtaining an interpenetrating network NiAl(Si)/Al2O3 composite, with very high hardness and melting point. While in the standard process the temperature for obtaining the Al(Si)/Al2O3 composites is in the 1100-1200 °C range, in this paper we studied instead the 700-1000 °C temperature range and its effect on the microstructure of the final NiAl(Si)/Al2O3 composite. After the first infiltration step, the microstructure of Al(Si)/Al2O3 composites depends on both temperature and time of the treatment. At 700-800 °C and for reaction time of 1-2 hours, the grain size is completely sub-micrometric. When temperature and time of reaction increase, islands with a coarser microstructure, of micrometric size, form, reaching a fully micrometric coarser microstructure at 1100-1200 °C. The islands formation is due to the transformation from transition aluminas, formed at low temperature and low reaction time, to α-alumina, while at high temperature α-alumina forms directly. In a second step, the Al(Si) metal network was replaced with an intermetallic one, by contacting the composite with liquid nickel, that reacted with the Al(Si) alloy forming an Al-Ni-Si intermetallic. The temperature and duration of the first infiltration step strongly influences not only the microstructure of the Al(Si)/Al2O3 composite but also of the final NiAl(Si)/Al2O3 one, that is finer when the first step (reaction of aluminum with silica) occurs at lower temperature.