Numerical Modeling of the Effects of Pore Characteristics on the Electric Breakdown of Rock for Plasma Pulse Geo Drilling

Drilling costs can be 80% of geothermal project investment, so decreasing these deep drilling costs substantially reduces overall project costs, contributing to less expensive geothermal electricity or heat generation. Plasma Pulse Geo Drilling (PPGD) is a contactless drilling technique that uses high-voltage pulses to fracture the rock without mechanical abrasion, which may reduce drilling costs by up to 90% of conventional mechanical rotary drilling costs. However, further development of PPGD requires a better understanding of the underlying fundamental physics, specifically the dielectric breakdown of rocks with pore fluids subjected to high-voltage pulses. This paper presents a numerical model to investigate the effects of the pore characteristics (i.e., pore fluid, shape, size, and pressure) on the occurrence of the local electric breakdown (i.e., plasma formation in the pore fluid) inside the granite pores and thus on PPGD efficiency. Investigated are: (i) two pore fluids, consisting of air (gas) or liquid water; (ii) three pore shapes, i.e., ellipses, circles, and squares; (iii) pore sizes ranging from 10 to 150 μm; (iv) pore pressures ranging from 0.1 to 2.5 MPa. The study shows how the investigated pore characteristics affect the local electric breakdown and, consequently, the PPGD process.

Building Information Modelling Technology in Mitigating Cost Overruns and change orders in Construction Projects

Variation order (VO) is one of the main issues faced by the construction industry in Jordan. Many researchers had investigated on the causes of VO and proposed procedures to minimize and control this issue; however, the VO is affecting the construction industry badly even at moment. Building Information Modeling (BIM) is a powerful management system that can make a significant difference in the project costs. However, BIM has not been examined as a tool to minimize the VO in Jordan. The main target of this study is to utilize BIM applications in reducing the effect of VO on the governmental projects in Jordan. In order to achieve this target, the researcher has designed a questionnaire to gather data related to VO causes and the BIM capability to solve this problem. The data collected from the questionnaires were analyzed statistically. The result from the analysis found that the consultant initiated the highest VO of 50% followed by the clients and the contractors of 20% and 10% unforeseen variation respectively. Moreover, it is found that BIM Design Applications, Facility Operations Simulation, Exploration Design Scenarios, BIM Design Detection and BIM Quantity Take-off and Cost Estimation were significantly capable of minimizing VO. The results show positive relationship with the application of BIM in minimizing VO in the construction industry in Jordan. © 2018. JASET, International Scholars and Researchers Association

Analisis Faktor Eksternal Yang Dominan Terhadap Biaya Overhead Proyek Konstruksi

ABSTRACTOverhead costs are one of the cost components that play an important role in the company's performance in maintaining good quality work. However, the overhead costs in a project are different and are influenced by several factors. One of the factors that influence it is the external factor of the project. The external factors of each project are different. This is because each project must adapt the workplace environment to certain functions, designs, and preferences. On that basis, to be able to better estimate the overhead in a project, further costs are needed for any external factors that affect construction overhead project costs, and a few percent of the direct costs of construction projects to anticipate the risks caused by overhead costs. . Data was collected through a structured questionnaire distributed to some people working in the construction sector from contractors in several regions in Indonesia. The analysis results obtained as many as 3 groups of external factors that affect construction project overhead costs, namely economic factors, legal factors, and sociocultural factors related to the COVID-19 pandemicABSTRAKBiaya overhead merupakan salah satu komponen biaya yang berperan dan berpengaruh penting terhadap kinerja perusahaan konstruksi dalam menjaga kualitas pekerjaan yang baik. Akan tetapi biaya overhead dalam suatu proyek berbeda-beda, dan dipengaruhi oleh beberapa faktor. Salah satu faktor yang mempengaruhinya ialah faktor eksternal proyek. Faktor eksternal dari setiap proyek berbeda-beda. Hal ini dikarenakan setiap proyek harus menyesuaikan lingkungan tempat kerja dengan fungsi, desain, serta prefensi tertentu. Atas dasar itu, untuk dapat lebih baik dalam mengestimasi biaya overhead dalam sebuah proyek maka diperlukan identifikasi lebih jauh terhadap faktor-faktor eksternal apa saja yang dominan berpengaruh terhadap biaya overhead proyek konstruksi, dan menyisihkan beberapa persen dari biaya langsung proyek konstruksi untuk mengantisipasi resiko yang disebabkan oleh biaya overhead. Data dikumpulkan melalui kuesioner terstruktur yang disebarkan kepada sejumlah orang yang bekerja di bidang konstruksi dari pihak kontraktor di beberapa wilayah di Indonesia. Dari hasil analisis diperoleh sebanyak 3 kelompok faktor eksternal yang dominan mempengaruhi biaya overhead proyek konstruksi, yaitu faktor ekonomi, faktor legal, dan faktor sosial-budaya yang juga berkenaan dengan adanya pandemi COVID-19.

Economic Contributions from Conserved Forests: Four Case Studies of the USDA Forest Service Forest Legacy Program

Privately-owned forests provide important environmental, economic, and cultural benefits to the general public. Resulting impacts from landownership changes and conversion of working forests to other land uses threaten these benefits. The USDA Forest Service Forest Legacy Program (FLP) permanently protects threatened private forests that are of environmental, cultural, and economic importance to the greater public while keeping land ownership and forest management at the private or local level. FLP provides grants to state agencies to purchase conservation easements on private forestlands or, less frequently, acquisition by public agencies. We employed IMPLAN’s input-output model of the 2016 economy to estimate how land protected by FLP in four regions of the United States contributes to the economy. FLP land adds tens of millions of dollars of value annually and supports thousands of jobs in the four study areas and, due to the permanent protection of these lands, they will continue to do so in perpetuity. Nonfederal partners contributed 34%–60% of total project costs, highlighting the importance of land conservation to multiple stakeholders and the ability to leverage federal resources. The permanent nature of FLP protection provides long-term security for the economic and cultural benefits these lands provide. Study Implications: The Forest Legacy Program (FLP) is administered by the USDA Forest Service to protect historic forest uses and intact working forest landscapes. This study quantified economic activities on FLP land in four areas to assess how these activities contribute to the economy of the multistate region in which the projects are located. The substantial economic contribution in natural resource industries suggests that permanent protection of forests provides economic and cultural benefits in perpetuity. This information illustrates the contributions of FLP to local economies and can be used to assess the value of the program and the potential for future funding.

The statistical sensitivity of highway project cost to geo-heterogeneity in the tropics

PurposeThe study is carried out to analytically reconnoiter geotechnical index properties of subgrade soils as key variables that shape the cost profile of road infrastructure projects in a tropical geographic setting with starkly heterogenous ground conditions.Design/methodology/approachUsing the Niger Delta region, as a point of reference, data on geotechnical index properties of subgrade soils at spatially dispersed locations for 61 completed highway projects are collated. Exploratory statistical tests were carried out to infer significant associations with final project costs before regression analysis. Regression analysis is principally deployed as an explanatory analytical tool, relevant to quantify the sensitivity of highway project costs to the individual and collective impact of geotechnical variables.FindingsSeveral parameters of expansivity and compressibility exhibited significantly strong associations with the final costs recorded on the highway projects. The statistical analysis further established a cause-effect relationship, whereby small changes in the geotechnical properties of sub-grade soils at project locations, would result in disproportionately large changes in the cost of road construction.Practical implicationsThe study findings provide insight into the sensitivity of road construction costs to geotechnical variables, which can serve as a useful input in financial risk analysis for development appraisal and the generation of location adjustment factors.Originality/valueThe study statistically demonstrates location-induced construction cost profiles, triggered in response to the spatial geotechnical variability and occurrence of problem subgrade soils in the humid tropics, which may be different from those traditionally established in studies of cold and temperate climate soils.

Renovation of Large-Panel Buildings: Peculiar Features in a Non-Capital Region

The period from 1957 to 1985 features mass industrial development — the construction of "Khrushchev-era buildings". Today, poor structural condition of these buildings represents an urgent challenge. The problem of "Khrushchev-era buildings" is especially urgent for the Irkutsk region due to specific climate conditions, materials used and mistakes made during their construction. Renovation in Irkutsk will allow honing the renovation techniques taking into account the seismic conditions of construction and a cold climate. The article deals with the development of a renovation standard project of a separate residential district in Irkutsk. The author's methodology is based on the content and sequence of stages of such a renovation. As a result, the authors have calculated project costs and profits and justified the conditions for obtaining commercial efficiency for a developer. It is shown that the renovation efficiency can be achieved when the area of residential buildings is doubled and more. Another prerequisite for successful renovation process is the recovery of expenses related to resettlement of citizens from demolished houses subsidized by the state buying out apartments for resettlement under programs of liquidation of dilapidated buildings. In conclusion, the authors point out advantages and drawbacks of the renovation for the population and municipal authorities.

Marine Energy Environmental Permitting and Compliance Costs

Costs to permit Marine Energy projects are poorly understood. In this paper we examine environmental compliance and permitting costs for 19 projects in the U.S., covering the last 2 decades. Guided discussions were conducted with developers over a 3-year period to obtain historical and ongoing project cost data relative to environmental studies (e.g., baseline or pre-project site characterization as well as post-installation effects monitoring), stakeholder outreach, and mitigation, as well as qualitative experience of the permitting process. Data are organized in categories of technology type, permitted capacity, pre- and post-installation, geographic location, and funding types. We also compare our findings with earlier logic models created for the Department of Energy (i.e., Reference Models). Environmental studies most commonly performed were for Fish and Fisheries, Noise, Marine Habitat/Benthic Studies and Marine Mammals. Studies for tidal projects were more expensive than those performed for wave projects and the range of reported project costs tended to be wider than ranges predicted by logic models. For eight projects reporting full project costs, from project start to FERC or USACE permit, the average amount for environmental permitting compliance was 14.6%.

Decision Framework to Balance Environmental, Technical, Logistical, and Economic Criteria When Designing Structures With Reused Components

The reuse of structural components in new buildings has great potential to reduce the environmental impacts of the construction sector but remains uncommon practice. An obstacle to its wider implementation is the lack of robust assessment methods and decision-making tools that consider the full spectrum of benefits and drawbacks. This paper proposes a multi-criteria decision framework that builds on a simulated set of design alternatives with varying ratios of reused and new structural components. A set of performance criteria is presented, addressing procurement risks, construction technique complexity, environmental impacts, and project costs. As the independent criterion evaluations often deliver conflicting results, a multi-criteria decision analysis helps identify the most appropriate solution. The design of a steel Pratt truss is used as a case study to demonstrate the applicability of the framework. Different alternatives with reuse rates above 65% are recommended for each preference scenario, reducing between 35 and 45% of adverse environmental impacts in comparison to an equivalent design made of new elements only. The study underpins the principle that there is no trivial and unique best option when designing with reused components. Multi-criteria decision analyses applied to structures with varying reuse rates constitute a promising tool to support decision-makers.

Fuzzy modelling and control of project cash flows

An analysis of the scientific literature on project cash flow control and fuzzy modelling shows that project cash flows are modelled using only basic approaches drawn from fuzzy theory, which may distort the credibility of the model. In this paper, we therefore propose to use the whole spectrum of fuzzy arithmetic, and to select operations that suit the nature of the cash flows in question, their dependencies and the preferences of the project manager. An analysis of the literature also shows that in practically all existing models of project costs and cash flow management, project costs and cash flows are treated at a very high level of generality (without considering the various types of project, factors influencing their variability and signals warning of imminent cash-related problems), and estimations are not updated on an ongoing basis throughout the duration of the project. The results of a survey performed with the participation of 100 project managers show that this simplistic view of project cash flows may be distorting, and cannot guarantee the development of an efficient project cost and cash flow control system. We propose an approach that at least partially compensates for these drawbacks: it differentiates between types of project cash flows and the factors and triggers affecting changes in cash flows. Two case studies are used for a an initial verification of the approach. The paper concludes with suggestions for further research perspectives.

Aplicación de la “Footprint Family” para la evaluación ambiental de edificios públicos en España. Estudio de caso: centro educativo

Within the commitments of the 2030 Agenda, the socio-economic objectives for a sustainable development of society as a whole, stand out, which propose minimizing the impact produced by all the activities of the Public Administration on the environment. Therefore, the creation and retrofitting of its infrastructures, needed for its operation and the services it provides, has a great impact. The goal of this work focuses on a methodological adaptation for the environmental evaluation of the works promoted by public organizations, quantifying and locating the sources of impact with the purpose of taking the measures to minimize them. For this, the footprint family, ecological, carbon, and water, are proposed as indicators, characterized by the simplicity of their message and the ease of their implementation in the construction sector, by controlling project costs. A case study is presented, the construction of an early childhood education center in the city of Madrid, for which the data needed for the calculation are presented and analyzed. The results reflect interesting information in terms of footprints, on the elements that must be controlled and improved in the project design, such as concrete and steel.