Extended Ultimate-Pit-Limit Methodology for Optimizing Surface-to-Underground Mining Transition in Metal Mines

The transition from surface mining to underground is a critical issue for metal mines. The commonly cited procedure cored by ultimate-pit-limit (UPL) methodology is restricted to maximize the profit from both surface and underground mining, due to the absence of the integration of the profit from either of them. Under the target for such maximization, this study proposes a new optimization approach, which directly relates the design of open-pit limit and underground stopes, by equalizing the marginal profit from either surface or underground mining. The variation of the crown pillar size is involved in this approach. The proposed approach is applied to the Dagushan iron mine, and results show the total profit increased from 3.79 billion CNYs (original design by conventional UPL methodology) to 4.17 billion CNYs (optimal design by the proposed approach), by 9.91%. Moreover, the marginal profit from surface and underground mining, as well as total profit, of all possible designs of surface-to-underground mining transition in Dagushan iron mine is calculated to validate the proposed approach. When the marginal profits satisfy the criterion of the proposed approach, the maximum value of the total profit appears, and this demonstrates the proposed approach is robust to maximize the total profit in surface-to-underground mining transition. This work contributes to existing literature studies primarily from practical aspect, by providing a unified approach to optimize the transition from surface to underground mining.

Algorithm to Estimate the Capacity Reserve of Existing Masonry Arch Railway Bridges

Most railway masonry arch bridges were designed according to codes that predate the 1950s; therefore, assessing their load-carrying capacity to comply with current codes is of the utmost importance. Nonetheless, acquiring the necessary information to conduct in-depth analyses is expensive and time consuming. In this article, we propose an expeditious procedure to conservatively assess the Load Rating Factor of masonry arch railway bridges based on a minimal set of information: the span, rise-to-span ratio, and design code. This method consists in applying the Static Theorem to determine the most conservative arch geometry compatible with the original design code; assuming this conservative geometrical configuration, the load rating factor, with respect to a different design load, is estimated. Using this algorithm, a parametric analysis was carried out to evaluate the Load Rating Factor of old arch bridges in respect of the modern freight load of the Trans-European Conventional Rail System, for different spans, rise-to-span ratios, and original design codes. The results are reported in easy-to-use charts, and summarized in simple, practical rules, which can help railway operators to rank their bridges based on capacity deficit.

Planted Roofs Over Buildings

Humans in addition with other factors have increased the environmental pollution of the planet. Many highly populated cities like Athens have problems with air quality due to the poor quality of construction, high temperatures in summer, noise, no existence of city plans, etc. The scope of this study is the investigation of urban towns' benefits using planted roofs. All types of planted roofs have many environmental, constructional, social, and financial benefits. The research suggests a method from the design, the study until the construction, using decision making, informing the citizens, and taking into account their opinion. The original design of buildings must have adopted an integrated energy strategy such as the solution of planted roofs so as to maximize the benefits to the environment and human beings. The research is specialized using a case study about a planted roof of an existing school building in Athens. The advantages and disadvantages of the usage are shown focusing on environmental, social, and construction aspects.

Operation and performance of the ATLAS semiconductor tracker in LHC Run 2

The semiconductor tracker (SCT) is one of the tracking systems for charged particles in the ATLAS detector. It consists of 4088 silicon strip sensor modules. During Run 2 (2015–2018) the Large Hadron Collider delivered an integrated luminosity of 156 fb-1 to the ATLAS experiment at a centre-of-mass proton-proton collision energy of 13 TeV. The instantaneous luminosity and pile-up conditions were far in excess of those assumed in the original design of the SCT detector. Due to improvements to the data acquisition system, the SCT operated stably throughout Run 2. It was available for 99.9% of the integrated luminosity and achieved a data-quality efficiency of 99.85%. Detailed studies have been made of the leakage current in SCT modules and the evolution of the full depletion voltage, which are used to study the impact of radiation damage to the modules.

DESIGN INNOVATION PROCESS RESPONDS TO UNMET NEEDS CREATED BY COVID-19

This article presents a recent case study of the development and bringing to market of a new product through the design process of the author, Dan Brown, Ph.D. (Brown Sr.), a product design practitioner and academic with over 40 years of innovation experience, and his son Brown Jr., a business entrepreneur. This case explores how they collaborated as an entrepreneurial team to design and commercialize a novel PPE face shield using Brown Sr.’s Differentiation by Design research process. The article focuses on how design creates value and competitive advantage in markets by examining a recent case study of successful new product development arising from the COVID-19 pandemic -- providing adequate personal protective equipment (PPE).When seeking advantage in the practice of innovation, there is a creative quest that product design and development practitioners must address through their design process. Truly innovative and competitive new products are rare, as their design efforts often fall short of the original design aims. Brown Sr.’s past research has revealed that this creative quest often appears at the intersection of the existing knowledge boundaries of the user as well as the many less prominent stakeholders in the new product experience.Often framed as unmet stakeholder needs, this knowledge boundary appears when existing practice knowledge proves inadequate, but the development objective remains. These knowledge gap opportunities appear through detailed research of the problem, existing solution benchmarks, and stakeholders. They can also appear when the designer-researcher looks for them specifically. Finding these knowledge gaps and creatively conceiving advantaged solutions into competitively advantaged spaces or white spaces is the goal of this design process.This Case shares successful marketplace outcomes with Brown Sr.’s past research cases resulting from their design and development approaches. With a combined quantitative and qualitative research focus, this autobiographical case study builds on the insights available to the researcher. Autobiographic cases provide unique access to rich quantitative evidence of the design narrative and marketing histories gained from an insider’s view of industry practice.Competitive advantage and its role in innovation in the real-world laboratory of the marketplace provide the context for researching the process of this design-focused strategy. The process starts with reframing the fundamental problem, which was, in this case, how to rapidly produce millions of face shields in a matter of months; the Browns teamed up to create a viable and scalable shield solution for the masses.

Value-Engineering Methodology for the Selection of an Optimal Bridge System

Maintaining and enhancing the functionality of the infrastructure at an affordable cost are major challenges for decision makers, particularly given the need to cope with growing societal and transportation demands. This study introduces a systematic multi-criteria value engineering (VE) approach for the selection of a sustainable bridge system. A thorough VE analysis for a proposed long-span bridge in New Jersey, USA was carried out as a pilot study. The function analysis system technique was used to develop logical relationships between the project’s functions. A detailed 100-year life-cycle cost analysis (LCCA) was conducted. The study developed and evaluated eight alternative designs for deck and superstructure systems against set VE criteria comprising constructability, maintenance strategies, and environmental impact. A relative value index was used as an unbiased measure for the selection of the optimal structural system. With total savings of approximately 21% of the original design ($132.5 million), steel plate girders with a high-performance lightweight steel grid deck system have proven to “outvalue” the other alternatives, including the preferred preliminary alternative (PPA). Design engineers and decision makers can use this methodology as a systematic and convenient guide for the selection of economical and sustainable bridge systems. As such, it is necessary to re-evaluate the current practices and policies used for this purpose.

Reducing the hydrodynamic force in the hydraulic distributor by modernizing the spool coupe parts

Due to a sharp change in the direction and velocity of the fluid flow in the hydraulic distributor, hydrodynamic forces arise. When positioning and holding the spool, the magnitude of the above forces determines the required control power. The aim of the article was to find an optimal constructive solution that would reduce the influence of hydrodynamic forces. In the article we have considered the theoretical foundations laid in the analytical solution of the problem of calculating the magnitude of the hydrodynamic force acting on the plunger of the spool. In addition, a numerical experiment was carried out using CAD Solidworks and the Flow Simulation application package and a comparison of the results obtained with the analytical solution of the problem. During the numerical experiment, it was found that by upgrading the spool sleeve, it is possible to reduce the value of the hydrodynamic force by 4.5 times, compared with the original design. At the same time, it was found that the modernization of the plunger does not further reduce the maximum hydrodynamic forces. The article highlights the economic benefits of reducing the required power to control the hydraulic distributor. The article may be of interest to both researchers whose research interests lie in the field of hydrodynamics, and manufacturers of hydraulics.

Analysis of the Causes of the Collapse of a Deep-Buried Large Cross-Section of Loess Tunnel and Evaluation of Treatment Measures

To address the problem of the collapse of the roof of the Bailuyuan tunnel during construction, the causes of collapse were analyzed, targeted treatment measures were proposed, and the effects of the treatment measures were evaluated through on-site monitoring and three-dimensional numerical simulations. The results showed that the particular characteristics of loess and the synergy of groundwater were the internal causes of the tunnel’s collapse as well as, to a certain extent, atmospheric precipitation. Therefore, the combination of multiple factors contributed to the tunnel’s collapse. Untimely monitoring and measurement, as well as the low initial support parameters, reflect a lack of human understanding of the collapse. Based on the analysis of the causes of the collapse, comprehensive treatment measures for inside and outside the tunnel are proposed, which are shown to be effective and to be capable of preventing the occurrence of further collapses. After the collapse treatment, the measured maximum settlement of the tunnel vault was 65.1 mm, the maximum horizontal convergence was 25 mm, the maximum surrounding rock pressure was 0.56 MPa, and the maximum stress on the steel arch frame was 54.34 MPa. Compared with the original design plan, the vertical stress, horizontal stress, and shear stress of the surrounding rock obtained from numerical simulation after the collapse treatment were greatly reduced, the reduction rate at the vault reached 50%, and the safety factors of the initial support positions after treatment met the specification requirements. The research results can provide engineering guidance for the design and construction of large-section tunnels crossing deep-loess strata, and they are of important engineering significance.

If Democracy Is Such a Smart Regime, Why Are Democracies Doing So Poorly at the Moment and How Can We Fix Them?

This chapter returns to the ideal of people’s power and argues that democracies as we know them are dubiously democratic. Most ordinary citizens, in the United States certainly but in other advanced democracies as well, have little deliberative input into the laws and policies that rule their lives. The chapter traces the problem to fundamental design mistakes made in the eighteenth century when elections, an oligarchic selection mechanism, rather than the traditional lot of Classical Athens, were privileged as the method for choosing representatives. This original design mistake explains in part why contemporary democracies are, and indeed have always been, dysfunctional. This chapter also makes the case for open democracy, a new paradigm of democracy that takes more seriously the core ideal of people’s power and in which elections are no longer a central institutional principle.