Simple Spreadsheet Calculations Research Articles

Modelling and Evaluation of Work Zone Queues: Istanbul Case Study

Road/lane closures due to maintenance works adversely affect the traffic conditions, causing delays in the various locations of the whole network. In Istanbul, Metropolitan Municipality charge the companies for the planned closure of the highways for a given time interval using simple spreadsheet calculations. These calculations include assumed capacity and speed values for each type of highway. In this paper, it is aimed to establish a methodology for the work zone evaluation that considers seasonality in demand and spatiotemporal variability in the flow and capacity. This goal will be achieved by observing and assessing the characteristics of İstanbul roadways and work zone areas. After the assessment, a traffic microsimulation software, namely PARAMICS, was used to simulate various road and work zone combinations to produce traffic data, including queue length, waiting times, vehicle speeds, flow and density of work zone section. Various machine-learning models were developed and their performance on test data will be analyzed. The selected model was used as a sub-model to estimate the expected delays, speeds and accelerations on different road types, different demands and lane closure combinations. A second sub-model used the delay, speed and acceleration values to estimate the total excess user cost due to road closure with determined delay-cost parameters.

Spreadsheet Calculation of Energy Based Method to Predict Temperature in Concrete Slabs

Under various fire scenarios, both heat transfer analysis and structural analysis are required to assess fire resistance of reinforced concrete member. For heat transfer analysis, Finite element method and Finite difference method are complicate for practical use. To simply predict temperature in concrete slab, the energy based method is a simplified FDM based on the predetermined temperature profile and the energy conservation. However, the method provides an inaccurate temperature prediction. To improve the prediction accuracy, this study reformulates the energy based method and investigates a suitable predetermined temperature profile. Furthermore, to facilitate design engineers, the method is proposed as a simple spreadsheet calculation. Through the empirical study of the FEM temperature profile, the exponent is found to be logarithmic proportional to the ratio of the lowest temperature to the highest in concrete slabs. The power function with variation of the exponent provides the better accurate temperature prediction. Comparing with FEM analysis and experimental results, the spreadsheet calculation is validated for temperature prediction of concrete slab under various fire loads.

Development and performance of new simplified method for soft soil with creep under multi-staged loading

In this paper, a new simplified method (de-coupled method) is presented for calculating consolidation settlements of a soft soil layer with creep under multi-staged loadings. All equations of this new simplified method are derived for a general multi-staged loading case. Different stress-states of the soil layer are considered. At the same time, a fully coupled finite element computer program with an Elastic Visco-Plastic (EVP) model and Hypothesis A method are used to calculate the consolidation settlements of the same soil layer with the same conditions. Then, the settlement results using this new simplified method are presented and compared with results from the finite element (FE) simulations and the Hypothesis A method. Based on the comparison, it is demonstrated that the new simplified method is much better than the Hypothesis A method. In addition, this new simplified method is used in the Berthierville test site subjected to three-staged loading. The comparison of calculated results and measured data demonstrates that the new simplified method is easy to use by simple spread-sheet calculation and has a good accuracy for the situations analyzed in this study.

Monitoring permeability potential of hot mix asphalt via binary aggregate packing principles correlated with Bailey ratios and porosity principles

Asphalt mix designs tend to optimise the load transfer via aggregate skeletons as main mechanism to provide rut resistance, often to the detriment of durability. Permeability, as a significant durability indicator, is more difficult to measure in the field than in the laboratory. Voids in the asphalt mix have a critical zone where an increase in voids is exponentially linked to permeability. This zone is where voids start to become increasingly interconnected. The aggregate grading envelope characteristics can provide an indication of the interconnectedness of the voids to enhance quality control. New rational Bailey Method Ratios (BMRs) were defined with contiguous aggregate fractions in the numerator and denominator. This allows also for porosity calculation using the Dominant Aggregate Size Range (DASR) method. The Binary Aggregate Packing (BAP) triangle porosity diagrams provide insight into the link between porosity and interconnected voids. The wall and the loosening effects create additional porosity (voids) with increased probability of interconnectedness. Clear threshold zones of interconnected voids can be determined with BAP coarse/fine mass ratios. The latter is the inverse of the rational BMRs. It allows for simple spreadsheet calculations of porosity and coarse/fine mass ratio as a screening tool for probable permeability via benchmark analysis. Reworked data sets demonstrated how the inverse of BMRs could show potential for interconnectedness of voids and, therefore, permeability propensity.

Well-Performance Calculations for Artificial-Lift Screening

This article, written by Special Publications Editor Adam Wilson, contains highlights of paper SPE 181344, “Well-Performance Calculations for Artificial-Lift Screening,” by P.A. Kefford, SPE, and M. Gaurav, Integrated Production Technologies, prepared for the 2016 SPE Annual Technical Conference and Exhibition, Dubai, 26–28 September. The paper has not been peer reviewed. Having the means to evaluate different forms of artificial lift efficiently early in the planning cycle significantly improves the ability to influence other planning decisions such as well count, well design, and facility capacities and to realize the potential benefits made available by new artificial-lift technologies. This paper focuses on a fit-for-purpose methodology to evaluate well-production performance for a wide range of artificial-lift techniques. Introduction In a typical artificial-lift selection process, the first stage, screening, involves considering a wide range of artificial-lift techniques and their suitability regarding fluid types, reservoir properties, and operating environment. Once a short list of feasible lift techniques is determined, a more-in-depth comparison of these options is undertaken by forecasting the performance over the life of the field. Options for generating such forecasts range from simple spreadsheet calculations to fully integrated asset models coupling detailed reservoir, well, and facilities models. The choice of forecasting technology depends largely on the field size and complexity. The next step is to perform an economic analysis to guide the ultimate selection of the preferred lift techniques. The economic analysis ac-counts for the capital and operational expenditure associated with each lift technique and uses the production profile to generate net-present-value estimates. The initial screening of artificial-lift technologies involves consideration of multiple criteria that will have varying degrees of significance depending on the specific reservoir properties and operating environment. Common artificial-lift screening criteria are Well productivity Operability Environmental effects Solids handling Well-design compatibility Flow assurance Reliability Gas handling Facilities requirements Power requirements Temperature limits Reservoir access Local knowledge/support New-technology risk Workover cost This paper focuses on the screening criteria related to a well’s hydraulic performance—namely, well productivity, gas-handling ability, and power requirements. Understanding what production rates are achievable with each lift technique in a particular environment, and knowing the interdependency these have with well count, well design, and facility capacities, is key to maximizing asset value. Equally important, quantifying how the free-gas volume entering artificial-lift equipment varies with drawdown and depth, and how this relates to the gas-handling capacity of the artificial-lift equipment, is necessary to ensure reliable operations without unduly constraining production. Finally, the power requirements have a direct effect on operational expenditures and, therefore, are important to quantify.

Substation Grounding Transfer of Potential Case Studies

Industrial substation grounding studies usually assume a simple isolated substation, follow the routine IEEE 80 design and analysis procedures using the software tools bundled with the power systems analysis suite of choice, and carry on with the rest of the project. However, there can be complications to substation grounding designs. This paper discusses two case studies where a ground fault in one substation generates a voltage which is transferred to other areas. The issues are assessed using common software tools supplemented with simple spreadsheet calculations. Some common limitations of the standard software tools, when applied to these more complex problems, are discussed in this paper, along with appropriate work-arounds. Mitigation methods are discussed.

Oil-recovery predictions for surfactant polymer flooding

There is increasing interest in surfactant–polymer (SP) flooding because of the need to increase oil production from depleted and water flooded reservoirs. Prediction of oil recovery from SP flooding, however, is complex and time consuming. Thus, a quick and easy method is needed to screen reservoirs for potential SP floods. This paper presents a scaling model that is capable of producing reasonable estimates of oil recovery for a SP flood using a simple spreadsheet calculation. The model is also useful for initial SP design. We present key dimensionless groups that control recovery for a SP flood. The proper physics for SP floods including the optimal salinity in the three-phase region and the trapping number for residual oil saturation determination has been incorporated. Based on these groups, a Box–Behnken experimental design is performed to generate response surface fits for oil recovery prediction at key dimensionless times. The response surfaces derived can be used to estimate the oil recovery potential for any given reservoir and are ideal for screening large databases of reservoirs to identify the most attractive chemical flooding candidates. The response function can also be used for proper design of key parameters for SP flooding. Our model will aid engineers to understand how key parameters affect oil recovery without performing time consuming chemical simulations. This is the first time that dimensionless groups for SP flooding have been derived comprehensively to obtain a response function of oil recovery as a function of dimensionless groups.

Exposure assessment in health assessments for hand-arm vibration syndrome

Assessing past cumulative vibration exposure is part of assessing the risk of hand-arm vibration syndrome (HAVS) in workers exposed to hand-arm vibration and invariably forms part of a medical assessment of such workers. To investigate the strength of relationships between the presence and severity of HAVS and different cumulative exposure metrics obtained from a self-reporting questionnaire. Cumulative exposure metrics were constructed from a tool-based questionnaire applied in a group of HAVS referrals and workplace field studies. These metrics included simple years of vibration exposure, cumulative total hours of all tool use and differing combinations of acceleration magnitudes for specific tools and their daily use, including the current frequency-weighting method contained in ISO 5349-1:2001. Use of simple years of exposure is a weak predictor of HAVS or its increasing severity. The calculation of cumulative hours across all vibrating tools used is a more powerful predictor. More complex calculations based on involving likely acceleration data for specific classes of tools, either frequency weighted or not, did not offer a clear further advantage in this dataset. This may be due to the uncertainty associated with workers' recall of their past tool usage or the variability between tools in the magnitude of their vibration emission. Assessing years of exposure or 'latency' in a worker should be replaced by cumulative hours of tool use. This can be readily obtained using a tool-pictogram-based self-reporting questionnaire and a simple spreadsheet calculation.

Managed-Pressure Drilling Using a Parasite Aerating String

Summary Drilling on top of the mesa in the Piceance basin presents a significant lost-circulation and stuck-pipe challenge to operators wanting to exploit the gas reserves in the area. Operators have experienced losses that exceed 4,000 bbl of mud when the intermediate section is drilled using conventional techniques. This is because of a combination of natural fractures and weak rock. Various strategies have been deployed to tackle the problems, including underbalanced-drilling (UBD) operations and directional casing while drilling. A new technique implemented by an operator in the Piceance basin is described in this paper; it involves acquiring real-time equivalent-circulating-density (ECD) data and control of mud weight in the annulus by use of direct air injection through a parasite aerating string (PAS). During the development stages of this new process, a real-time annular-pressure sensor was run in the bottomhole assembly (BHA) to gather diagnostic data. Analysis of the data shows conventional drilling practices often yield up to 3 lbm/gal variation in ECD exposed to the formation. The analysis also suggests that there is a fracture-reopening gradient of approximately 8.3 lbm/gal and that there are significant ECD variations during connections. The new strategy shows that these wells can be drilled with an ECD in the range of 5-7 lbm/gal using conventional water-based-mud systems. This strategy allows wells with a narrow mud-weight window to be drilled without significant mud loss to the formation. This approach avoids the use of complex multiphase models, and the downhole ECD can be displayed on the driller's console in real time from the data measured by the annular-pressure sensor and sent through the mud-pulse-telemetry measurement-while-drilling (MWD) tool. Alternatively, if an annular-pressure sensor is not included in the BHA, the downhole ECD can still be estimated accurately by use of a simple spreadsheet calculation (Scott 2009). This gives a measure of flexibility in deploying the technique to the wellsite. Expert personnel were used in the initial diagnostic stages to establish the procedures and validate the effectiveness of the technique. After that, they will not normally be required at the wellsite to manage the process in subsequent wells because the ECD data from the annular-pressure sensor can be understood by the driller, and the alternative spreadsheet solution, if used, can also be managed by the wellsite supervisor to calculate a reliable downhole ECD measurement. The ECD data enable the driller to control and keep the annular pressure within recommended limits, ensuring that lost circulation risk is reduced and wellbore stability is maintained. The alternative approach of using conventional well-design techniques would result in multiple casing strings and in cost overruns, while more-advanced techniques such as directional casing while drilling and UBD would require specialized equipment and crews. This new technique uses existing and common drilling technologies along with new software tools for geomechanics analysis and drilling surveillance to achieve a fit-for-purpose solution. This paper presents a risk-management technique using today's conventional technologies to successfully mitigate lost circulation risk in the Piceance basin.

A Simple Parametric Model for the Analysis of Cooled Gas Turbines

A natural gas fired gas turbine combined cycle power plant is the most efficient option for fossil fuel based electric power generation that is commercially available. Trade publications report that currently available technology is rated near 60% thermal efficiency. Research and development efforts are in place targeting even higher efficiencies in the next two decades. In the face of diminishing natural resources and increasing carbon dioxide emissions, leading to greenhouse gas effect and global warming, these efforts are even more critical today than in the last century. The main performance driver in a combined cycle power plant is the gas turbine. The basic thermodynamics of the gas turbine, described by the well-known Brayton cycle, dictates that the key design parameters that determine the gas turbine performance are the cycle pressure ratio and maximum cycle temperature at the turbine inlet. While performance calculations for an ideal gas turbine are straightforward with compact mathematical formulations, detailed engineering analysis of real machines with turbine hot gas path cooling requires complex models. Such models, requisite for detailed engineering design work, involve highly empirical heat transfer formulations embedded in a complex system of equations that are amenable only to numerical solutions. A cooled turbine modeling system incorporating all pertinent physical phenomena into compact formulations is developed and presented in this paper. The model is fully physics-based and amenable to simple spreadsheet calculations while illustrating the basic principles with sufficient accuracy and extreme qualitative rigor. This model is valuable not only as a teaching and training tool, it is also suitable to preliminary gas turbine combined cycle design calculations in narrowing down the field of feasible design options.

Optimierung forstlicher Produktion unter Beachtung von finanziellen Restriktionen | Optimisation of forest production under financial restrictions

The question of efficiency of resources bound in the silvicultural (biological) production of forest enterprises strikes a central topic of forest management. Using simple spreadsheet calculation models, this paper tries to explicate the relations between silvicultural treatments and economic evaluation criteria under financial restrictions. By means of actual examples, concerning thinning intensity and final harvest age under the restriction of maintenance of capital, practical silvicultural behaviour can be seen as compatible with the optimal economic solutions, determined by the model calculations. This leads to the conclusion that commonly practiced concepts of thinning intensity and productivity dependent harvest age can be interpreted as rational economic behaviour. With reference to such an economic optimum the consequences of changes in forest management, as they are often claimed for instance by directives of nature conservation, water protection etc., can be evaluated based on opportunity costs.

A Graded Approach to Flow and Transport Modeling to Support Decommissioning Activities at the Savannah River Site

A graded approach to flow and transport modeling has been used as a cost effective solution to evaluating potential groundwater risk in support of Deactivation and Decommissioning activities at the United States Department of Energy's Savannah River Site (SRS) in Aiken, South Carolina. This approach balances modeling complexity with potential risk and has been successfully used at SRS to reduce costs and accelerate schedule without compromising human health or the environment. The approach incorporates both simple spreadsheet calculations (i.e., screening models) and complex numerical modeling to evaluate the threat to human health posed by contaminants leaching from decommissioned concrete building slabs. Simple spreadsheet calculations were used to produce generic slab concentration limits for a suite of radiological and non-radiological contaminants for a chemical separations area at SRS. These limits, which are based upon the United States Environmental Protection Agency Soil Screening Guidance, were used to eliminate most building slabs from further risk assessment, thereby limiting the time and associated cost of the more rigorous assessment to higher risk facilities. Of the more than 58 facilities located in the area, to date only one slab has been found to have a contaminant concentration in excess of the area specific slab limit. For this slab, a more rigorous numerical modeling effort was undertaken which eliminated some of the simplifying and conservative assumptions inherent in the spreadsheet calculations. Results from the more sophisticated numerical model show that the remaining contaminant of concern would not likely impact groundwater above drinking water standards.

Quantitative Risk Assessment for Bovine Spongiform Encephalopathy in Low‐ or Zero‐Prevalence Countries: The Example of Norway

A predictive case-cohort model is applied to Norwegian data to analyze the interaction between challenge and stability factors for bovine spongiform encephalopathy (BSE) during the period 1980-2010. For each year, the BSE risk in cattle is estimated as the expected number of cases. The age distribution of expected cases as well as the relative impact of different challenges is estimated. The model consists of a simple, transparent, and practical deterministic spreadsheet calculation model, in which the following country-specific inputs are entered: (i) annual imports of live cattle and meat and bone meal, (ii) age distribution of native cattle, and (iii) estimated annual basic reproduction ratio (R(0)) for BSE. Results for Norway indicate that the highest risk of BSE cases was in 1989, when a total BSE risk of 0.13 cases per year was expected. After that date, the year-to-year decrease in risk ranged between 3% and 47%, except for a secondary peak in 1994 at 0.06 cases per year. The primary peak was almost entirely (99%) attributable to the importation of 11 cattle from the United Kingdom between 1982 and 1986. The secondary peak, in 1994, originated mainly from the recycling of the U.K. imported cattle (92%). In 2006, the remaining risk was 0.0003 cases per year, or 0.001 per million cows per year, with a maximal age-specific incidence of 0.03 cases per million per year in 10-year-old cattle. Only 15% of the cases were expected in imported cattle. The probability of having zero cases in Norway in 2006 was estimated to be 99.97%. The model and results are compared to previous risk assessments of Norway by the EU.

Evaluating a novel Test Site Analysis (TSA) bioassessment approach

AbstractWe compared the performance of Test Site Analysis (TSA) to 2 existing bioassessment methods: the BEnthic Assessment of SedimenT (BEAST), and the multimetric approach. In TSA, simple spreadsheet calculations are used to: 1) derive an overall multivariate measure of dissimilarity between a potentially impaired test site and a reference benchmark using a number of biological summary metrics, 2) classify each site as impaired, potentially impaired, or in reference condition with formal hypothesis tests, and 3) identify the metrics important in distinguishing a significantly impaired test site from the reference benchmark. We used data collected as part of the Fraser River Action Plan (British Columbia, Canada) to compare the biological condition of 15 potentially impaired test sites known to be exposed to agriculture, logging, or mining to the condition of 61 minimally disturbed reference sites with comparable habitat. When TSA was used, the false-positive (i.e., Type-1 error) and false-negative (i.e....

Simplified parameter identification for circular tunnels

A fundamental component of the observational method in tunneling is the use of monitoring data to assess the adequacy of the employed design. Monitoring data can also be used to calibrate numerical or analytical models. In this paper a simplified back-analysis procedure to calibrate models based on a statistical framework is examined. The method can be quickly used as a first degree approximation of the actual problem using simple spreadsheet calculations. (A) This paper was presented at Safety in the underground space - Proceedings of the ITA-AITES 2006 World Tunnel Congress and the 32nd ITA General Assembly, Seoul, Korea, 22-27 April 2006. For the covering abstract see ITRD E129148. Reprinted with permission from Elsevier.

NOAA HABITAT RECOVERY MODELS USING CELLULAR AUTOMATA TECHNIQUES1

ABSTRACT Models that predict characteristics of habitat recovery following disturbance are useful tools for ecological risk assessment as well as natural resource damage assessment. NOAA is evaluating the suitability of cellular automata as a single modeling framework for simulating several habitat types (seagrass, coral, rocky intertidal and marsh). The primary challenge is creating rules that reflect biological relationships and complexity. The desire for biological realism in the model is balanced by the need for simplicity in the defined relationships. Once the rules are defined, cellular automata models are straightforward to construct and modify during development. The cellular automata technique divides a domain into discrete cells with a finite number of states. For habitat models dominated or characterized by a single species (e.g. seagrass, coral or marsh), the cells are defined with two states: empty and occupied. For the multiple species models (e.g. rocky intertidal), the cells are either empty (bare rock) or occupied by one of four biological covers: Fucus, barnacles, mussels, or “other” (e.g., coralline algae or red algal turf). Probabilistic rules are generated for cell transitions from one state (or dominant species) to another. In cases where there is not spatial influence, the model can be collapsed into a simple spreadsheet calculation. Though some ecosystems recover in timescales shorter than decades, some of these ecosystems recover over time periods longer than a human lifespan. Thus simulation modeling is the only feasible means to provide reasonable guidance for their final recovery. Within this modeling system, the user can create an initial distribution of species, and then choose either to run the simulation from the initial beach, or to selectively empty cells to create a specific type of disturbance before running the simulation. The goal for this work is to both intuitively (graphically) (1) display tradeoffs from the use of different cleanup and restoration techniques and (2) to provide a defensible and quantitative recovery forecast for computing monetary damages against responsible parties.

Newsvendor Bounds and Heuristic for Optimal Policies in Serial Supply Chains

We consider the classic N-stage serial supply systems with linear costs and stationary random demands. There are deterministic transportation leadtimes between stages, and unsatisfied demands are backlogged. The optimal inventory policy for this system is known to be an echelon base-stock policy, which can be computed through minimizing N nested convex functions recursively. To identify the key determinants of the optimal policy, we develop a simple and surprisingly good heuristic. This method minimizes 2Nseparate newsvendor-type cost functions, each of which uses the original problem data only. These functions are lower and upper bounds for the echelon cost functions; their minimizers form bounds for the optimal echelon base-stock levels. The heuristic is the simple average of the solution bounds. In extensive numerical experiments, the average relative error of the heuristic is 0.24%, with the maximum error less than 1.5%. The bounds and the heuristic, which can be easily obtained by simple spreadsheet calculations, enhance the accessibility and implementability of the multiechelon inventory theory. More importantly, the closed-form expressions provide an analytical tool for us to gain insights into issues such as system bottlenecks, effects of system parameters, and coordination mechanisms in decentralized systems.

Modelling for the planning and management of bed capacities in hospitals

The internal dynamics of a hospital represent a complex non-linear structure. Planning and management of bed capacities must be evaluated within an environment of uncertainty, variability and limited resources. A common approach is to plan and manage capacities based on simple deterministic spreadsheet calculations. This paper demonstrates that these calculations typically do not provide the appropriate information and result in underestimating true bed requirements. More sophisticated, flexible and necessarily detailed capacity models are needed. The development and use of such a simulation model is presented in this paper. The modelling work, in conjunction with a major UK NHS Trust, considers various types of patient flows, at the individual patient level, and resulting bed needs over time. The consequence of changes in capacity planning policies and management of existing capacities can be readily examined. The work has highlighted the need for evaluating hospital bed capacities in light of both bed occupancies and refused admission rates. The relationship between occupancy and refusals is complex and often overlooked by hospital managers.

The use of vector calculus in calculating areas of geometrical shapes in shade or in direct sunlight

Many building services consultancies use commercial software to predict which surfaces of a building are in direct sunlight and which are in shade at any given time in the year. Such an approach can yield very satisfuctory results and a large number of 'pretty pictures'. However, it does not lend itself to an understanding of what the basic physical principles are behind such a calculation. Such an analysis is particularly useful in calculating the solar gain for the large glazed geometrical shapes particularly beloved of architects. This paper is an attempt to explain these principles and to enable simple spreadsheet calculations to be carried out. The work described was carried out as part of the environmental analysis and design of the Great Glasshouse at the National Botanic Garden of Wales, Llanarthne, Carmarthenshirew.

Electricity generation in the home: modelling of single-house domestic combined heat and power

Two models for predicting potential savings from a domestic combined heat and power unit are developed and compared. The first, a simple spreadsheet calculation based on heating times and energy bills, gives a basic indication of the benefits of domestic combined heat and power. The second predicts the electricity and heat demand profiles of homes based on building structure, weather information and house energy bills, and simulates the operation of the unit to enable the savings for different ratings and efficiencies to be predicted.