Contractor’s Financial Estimation based on Owner Payment Histories

A contractor’s financial viability is affected by late and incomplete payments from the owner. Late and incomplete payments lead to cash flow uncertainty, additional bank interest, and delays in paying creditors such as suppliers and subcontractors, and may lead to decreased project performance, and possible additional time and cost due to disputes. The paper presents a method for cash flow and present value analysis under uncertainty based on an owner’s payment history or estimated payment characteristics. The paper generalises existing modelling of uncertainty associated with late and incomplete owner payments to a range of claim types by the contractor, and different owner types. Aging contractor claims are analysed for claims submitted on a regular basis for amounts which may vary depending on project phasing. For each of the pre-identified typical owner payment practices, the estimated paid proportions of claims and the steady state distribution of payments in different age categories are established. A present value analysis assesses project viability from the contractor’s viewpoint. Actual project data are used to confirm the validity of the method. The intent of the paper is to assist contractors establish suitable allowances in their tender pricing, to choose a suitable claim/payment schedule and/or to adopt suitable administration practices to optimise cash flow. The paper gives a summary approach for contractors, providing them with a practical tool in cash flow planning, control and risk management

Emission and Cost Configurations in Earthmoving Operations

Brief introduction to the problem. The paper examines the influence of varying operation parameters such as equipment heterogeneity, payload, and travel times, on unit emissions and unit costs in earthmoving and like operations. The need to minimise cost and maximise production of earthmoving and like operations has led to such operations being heavily scrutinised. With environmental issues becoming more important, there is now a need to additionally scrutinise and minimise emissions. Cycle times and production were measured in a cut-and-fill case study operation; average fuel burn data are converted to idling and nonidling emission fractions; and queuing theory is used for the theoretical evaluation of production for varying operation parameters. It is demonstrated that the optimum fleet sizes in terms of minimum unit costs and minimum unit emissions coincide in earthmoving operations. The result is independent of any specific operational parameters. The paper concludes that the traditional way of undertaking earthmoving operations, namely configuring to give minimum unit costs, will also result in minimum unit emissions. And that configuring differently to that will lead to unnecessary emissions. The result carries over to quarrying and surface mining operations

Coherent generation of EPR-entangled light pulses mediated by a single trapped atom

We show that a single, trapped, laser-driven atom in a high-finesse optical cavity allows for the quantum-coherent generation of entangled light pulses on demand. Schemes for generating simultaneous and temporally separated pulse pairs are proposed. The mechanical effect of the laser excitation on the quantum motion of the cold trapped atom mediates the entangling interaction between two cavity modes and between the two subsequent pulses, respectively. The entanglement is of EPR-type, and its degree can be controlled through external parameters. At the end of the generation process the atom is decorrelated from the light field. Possible experimental implementations of the proposals are discussed.Comment: 11 pages, 4 figure

Contractor’s Financial Estimation based on Owner Payment Histories

A contractor’s financial viability is affected by late and incomplete payments from the owner. Late and incomplete payments lead to cash flow uncertainty, additional bank interest, and delays in paying creditors such as suppliers and subcontractors, and may lead to decreased project performance, and possible additional time and cost due to disputes. The paper presents a method for cash flow and present value analysis under uncertainty based on an owner’s payment history or estimated payment characteristics. The paper generalises existing modelling of uncertainty associated with late and incomplete owner payments to a range of claim types by the contractor, and different owner types. Aging contractor claims are analysed for claims submitted on a regular basis for amounts which may vary depending on project phasing. For each of the pre-identified typical owner payment practices, the estimated paid proportions of claims and the steady state distribution of payments in different age categories are established. A present value analysis assesses project viability from the contractor’s viewpoint. Actual project data are used to confirm the validity of the method. The intent of the paper is to assist contractors establish suitable allowances in their tender pricing, to choose a suitable claim/payment schedule and/or to adopt suitable administration practices to optimise cash flow. The paper gives a summary approach for contractors, providing them with a practical tool in cash flow planning, control and risk management

Valuing deliberate built-in flexibility in houses – exampled

People’s Housing requirements commonly transition over time, and there are financial, social and environmental impacts associated with altering and moving houses. With possible future alteration in mind, this paper looks at the viability of deliberately incorporating flexibility into houses at the time they are designed and built, as compared with no specifically incorporated flexibility (yet still possibly capable of being altered). A comparative analysis, rather than an absolute analysis, is outlined. The financial viability is performed as an options analysis, while the social and environmental matters are evaluated along life cycle assessment lines. As a case example, the paper considers the viability of incorporating deliberate two-storey flexibility into a single-storey house using Australian practices. It is shown on the case example that incorporating deliberate built-in flexibility can perform positively against all sustainability criteria – financial, social and environmental, separately or combined – however the generality of this conclusion remains to be proven

The effect on photochemical smog of converting the U.S. fleet of gasoline vehicles to modern diesel vehicles

With the increased use of particle traps and nitrogen oxide (NO_x) control devices to reduce air pollution, “modern” diesel vehicles are being encouraged over gasoline vehicles globally as a central method of slowing global warming. Data to date, though, suggest that the NO_2:NO ratio from modern diesel may exceed that of gasoline, and it is difficult to reduce diesel NO_x below gasoline NO_x without increasing particle emissions. Here, it is calculated that, unless the diesel NO_2:NO ratio and total NO_x are reduced to those of gasoline, modern diesel, which should have lower hydrocarbon (HC) and carbon monoxide (CO) emissions than gasoline, may still enhance photochemical smog at the surface and aloft, on average, over the U.S. relative to gasoline. The reason is that vehicle-produced smog in the U.S. depends more on NO_x and the NO_2:NO ratio than on HCs or CO. It is also found that vehicle NO_x controls may be more effective than NO_2:NO ratio controls at reducing ozone

Optimal outcome sharing with a consortium of contractors

Where a consortium of contractors is involved, there exist no guidelines in the literature on what the outcome sharing arrangement should be. The paper addresses this shortfall. It derives the optimal outcome sharing arrangement for risk-neutral and risk-averse contractors within the consortium, and between the consortium and a risk-neutral owner. Practitioners were engaged in a designed exercise in order to validate the paper’s propositions. The paper demonstrates that, at the optimum: the proportion of outcome sharing among contractors with the same risk-attitude should reflect the levels of their contributions; the proportion of outcome sharing among contractors with the same level of contribu­tion should be lower for contractors with higher levels of risk aversion; a consortium of risk-neutral contractors should receive or bear any favourable or adverse project outcome respectively; and the proportion of outcome sharing to a con­sortium of risk-averse contractors should reduce, and the fixed component of the consortium fee should increase, when the contractors become more risk-averse or the level of the project outcome uncertainty increases. The paper proposes an original solution to the optimal sharing problem in contracts with a consortium of contractors, thereby contributing to current practices in contracts management. First published online: 14 Sep 201

Emission and Cost Configurations in Earthmoving Operations

Brief introduction to the problem. The paper examines the influence of varying operation parameters such as equipment heterogeneity, payload, and travel times, on unit emissions and unit costs in earthmoving and like operations. The need to minimise cost and maximise production of earthmoving and like operations has led to such operations being heavily scrutinised. With environmental issues becoming more important, there is now a need to additionally scrutinise and minimise emissions. Cycle times and production were measured in a cut-and-fill case study operation; average fuel burn data are converted to idling and nonidling emission fractions; and queuing theory is used for the theoretical evaluation of production for varying operation parameters. It is demonstrated that the optimum fleet sizes in terms of minimum unit costs and minimum unit emissions coincide in earthmoving operations. The result is independent of any specific operational parameters. The paper concludes that the traditional way of undertaking earthmoving operations, namely configuring to give minimum unit costs, will also result in minimum unit emissions. And that configuring differently to that will lead to unnecessary emissions. The result carries over to quarrying and surface mining operations

Statistics of excitons in quantum dots and the resulting microcavity emission spectra

A theoretical investigation is presented of the statistics of excitons in quantum dots (QDs) of different sizes. A formalism is developed to build the exciton creation operator in a dot from the single exciton wavefunction and it is shown how this operator evolves from purely fermionic, in case of a small QD, to purely bosonic, in case of large QDs. Nonlinear optical emission spectra of semiconductor microcavities containing single QDs are found to exhibit a peculiar multiplet structure which reduces to Mollow triplet and Rabi doublet in fermionic and bosonic limits, respectively.Comment: Extensively expanded revision, 14 pages, 12 figures, submitted to Phys. Rev.

Urban planning as an enabler of urban health: Challenges and good practice in England following the 2012 planning and public health reforms

© 2019 The Authors This article synthesises the challenges faced by the English (urban) spatial planning system to become an enabler of urban health and explores some keys features of the evidence base, policy tools and policy implementation issues that urban planners need to be aware of to become health enablers. It draws on good practice identified in an Economic and Social Research Council (ESRC) seminar series involving over 500 academic researchers and practitioners between 2015 and 2017. A number of key recommendations emerged out of the project. First, planning and health agendas must align at the local level. Second, the evidence base of health priorities must be locally relevant. Third, robust tools can support the creation of frameworks for delivering health outcomes through planning. And finally, adequate resources are necessary to develop the capacity of key place-making stakeholders