弹性宽刃精车刀与细长轴的加工

介绍了自制弹性宽刃精车刀对细长轴进行加工,以及加工工艺和加工中要注意的若干问题.     

Supply-side inoperability input–output model (SIIM) for risk analysis in manufacturing systems

This paper proposes a methodological approach in risk analysis of interdependent manufacturing systems which is based on Ghosh model - a variation of the Leontief input-output model. The proposed approach is able to quantify the impact of supply perturbations in a manufacturing system in terms of cost-price increase in production output due to increase in prices of value-added input brought about by degraded supply resulting from natural or man-made disasters and sudden policy changes. Unlike demand-driven perturbation models presented in literature, the supply-driven inoperability input-output model (SIIM) appears to be more relevant particularly in make-to-order manufacturing systems as demand is usually pre-determined and production costs typically increase when prices of inputs increase. An actual case study was carried out in a furniture manufacturing firm in central Philippines and three scenarios were presented to illustrate the proposed approach: (1) a sudden log ban in the location of the supplier, (2) increase in labor costs and (3) metal shortage caused by severe weather condition. Results show that supply perturbation of upstream processes does not impact downstream processes as long as these processes remain independent of the perturbed upstream process as described in firm's system structure and topology. This also shows that the magnitude of impact of non-perturbed process depends on its nature of interdependence of the perturbed process. The proposed approach is highly relevant for manufacturing practitioners in formulating and implementing mitigation and adaptation policies.     

Book review

The goal of this study is to extend Rasmussen's framework for risk management to research organisations having to deal with reduced income from government funding and increased market orientation. One human factors research organisation was studied in detail. Using archival records, changes were studied over the period 1989–2010. The results showed an increase in income from market funding relative to government funding, and a decrease in written output. Predictions by stress–strain theory were confirmed in that during the first 5 years of the period under consideration, a linear relationship between the increase in market funding and written output was observed, whereas a nonlinear relationship was observed in the next 5–10 years, indicating a larger decrease in written output than would be expected. Generally, the results show that research organisations are adaptive systems that trade off resource allocation to either commercial activities or scientific activities, depending on incentive schemes.     

Assessing low-carbon energy technologies against sustainability and resilience criteria: results of a European experts survey

The aim of this article is the assessment of low-carbon energy technologies in Europe against a set of sustainability and resilience criteria. The assessment was based on a survey that was conducted among 40 European experts. Solar Photovoltaic was the technology that proved to achieve high performance against many criteria, whereas nuclear was assessed by the experts with relatively low performance against most of the criteria. Furthermore, it became evident that there is high degree of convergence between the experts, and therefore high degree of confidence, on specific aspects such as the high level of public resistance against Nuclear and the low stability of energy generation of wind onshore. The experts had major disagreements on the performance of carbon capture and storage (CCS) technologies against technological maturity and innovative ability criteria, which reveals a high degree of uncertainty on how CCS will be deployed in the future, pointing out a direction for future research.     

Layer-by-layer assembly of long-afterglow self-supporting thin films with dual-stimuli-responsive phosphorescence and antiforgery applications

The assembly of thin films (TFs) having long-lasting luminescence can be expected to play an important role in the development of new-generation smart sensors,anti-counterfeiting materials,and information-encryption systems.However,such films are limited compared with their powder and solution counterparts.In this study,by exploiting the self-organization of phosphors in the two-dimensional (2D) galleries between clay nanosheets,we developed a method for the ordered assembly of long-afterglow TFs by utilizing a hydrogen-bonding layer-by-layer (LBL) process.Compared with the pristine powder,the TFs exhibit high polarization and up-conversion room-temperature phosphorescence (RTP),as well as enhanced quantum yields and luminescence lifetimes,allowing them to be used as room-temperature phosphorescent sensors for humidity and oxygen.Moreover,modified day-based hybrids with multicolor RTP can serve as anti-counterfeiting marks and triple-mode 2D barcode displays.We anticipate that the LBL assembly process can be extended to the fabrication of other inorganic-organic room-temperature phosphorescent hybrids with smart luminescent sensor and antiforgery applications.     

Defining resilience for the US building industry

ABSTRACT

Initiatives to operationalize the concept of resilience in the building industry are rapidly emerging. The concept of resilience has introduced a way to explore solutions to some important problems in the building industry. However, much of the work that has taken place to date represents activities generally assigned to risk management, which is discussed as being inherently insufficient for sustaining the functions of the built environment under stresses. This commentary considers the opportunities and limitations for mainstreaming resilience into building industry processes and actors. Barriers include indeterminate analytical meaning, event and performance uncertainty, immature regulatory standards setting, and untested enterprise economics. Further, the multiple outcomes of recovery and the relationship between building recovery and adaptation are discussed and, along with economics of resilience investments, a research need highlighted. A simple heuristic is presented to illustrate the complement of resilience to risk management and advance the integration of resilience into existing industry workflows.     

Why underground space should be included in urban planning policy – And how this will enhance an urban underground future

Cities worldwide tend to overlook an invaluable asset that lies beneath their surfaces. Most cities and urban regions are unaware of the benefits underground space use has to offer, both for climate inflicted and spatial constraints: In many cities, infrastructure development is being outpaced by population growth. Climate change effects are requiring radical new approaches in terms of coping with for example excessive rainfall. The available space at the surface is rapidly being used up and the biggest danger is that built-up spaces are taking over the public green spaces of cities thereby threatening livability and quality of life. Urban underground space forms a societal asset, which is often unappreciated and underestimated in terms of the role it can play within dynamic city environments and associated challenges.This paper will explore the ways in which urban underground space can be optimally integrated into the dynamic urban context. It also explores the often contradictory functions that make underground space use complicated from a planner’s perspective. The first-come-first-served strategy of underground space use has left many cities wondering how they are going to cope with the self-inflicted “chaos” under the surface. The often mono-functional uses of the underground lead to sub-optimal space use. Most cities and urban regions are unaware of the benefits underground space use has to offer. In guiding the future use of urban underground space, a comprehensive policy framework guiding its development is lacking on which decisions can be based. This often leads to the non-sustainable use of this important asset. It will be argued that both vision and planning are needed to be able to make the best use of this underrated underground real estate.The authors will also debate that just understanding the potential of underground space is not enough. Realising its actual potential and facilitating its development will require a spatial dialogue between many stakeholders, including planners, engineers, developers and public decision makers.     

Design of a discrete-time output-feedback based repetitive-control system

This paper deals with the problem of designing a robust discrete output-feedback based repetitive-control system for a class of linear plants with periodic uncertainties. The periodicity of the repetitive-control system is exploited to establish a two-dimensional (2D) model that converts the design problem into a robust stabilization problem for a discrete 2D system. By employing Lyapunov stability theory and the singular-value decomposition of the output matrix, a linear-matrix-inequality (LMI) based stability condition is derived. The condition can be used directly to design the gains of the repetitive controller. Two tuning parameters in the LMI enable the preferential adjustment of control and learning. A numerical example illustrates the design procedure and demonstrates the validity of the method.     

Residualisation and resilience: public housing in Hong Kong

Public housing has been an important element in the welfare state and a substantial literature has analysed its origins and growth in different places. However, as it has matured and been redefined by privatisation and regeneration, debates have changed and increasingly been concerned with residualisation and decline. This paper outlines considerations affecting comparative analysis of public housing and presents new material related to explanations for the resilience of public housing in Hong Kong.     

Effects of Internal and External Connection of Electrodes in Diagonal Type Nonequilibrium Plasma MHD Generator

In this paper, by a two-dimensional analysis in the duct cross section perpendicular to the plasma flow, the authors investigate comparatively the current distribution, the electrical efficiency etc. in the diagonal type nonequilibrium plasma generator of the window frame construction and the one of the insulating sidewall. Their numerical computations are made for an example of the cesium-seeded helium in nonequilibrium ionization, where it is assumed that the ionization instability does not occur.

It is shown that the current in the generator duct of the diagonal conducting wall tends to flow uniformly in the cross section of the duct, and on the other hand, the current in the duct of the insulating sidewall does in its central part; thus the performance characteristics of the former becomes better than those of the latter. This tendency increases with the load factor and wall temperature of the generator. Also the generator characteristics are improved with increasing the inclination factor, and the electrode voltage drop decreases with the load factor.