Crystal Ball Software Research Articles

Spatial analysis and probabilistic risk assessment of exposure to fluoride in drinking water using GIS and Monte Carlo simulation.

Prevalence of fluorosis is a worldwide public health problem especially in many states of India. It is necessary to find out the fluoride endemic areas to adopt remedial measures to the people on the risk of fluorosis. The target goals of this research were to assess (a) the exposure of fluoride concentration; (b) probabilistic risk assessment, sensitivity analysis, and uncertainty through intake of groundwater among population of Agra City (infants, children and adults) by Crystal Ball software; and (c) spatial distribution of HQ and fluoride concentration. A total of sixty samples from standing tube wells/hand pumps were gathered from selected and identified fluoride prevalent areas in Agra City. The concentration of fluoride scrutinized was obtained to be ranging from 1.32 to 4.60 mg/L with mean value of 2.36 in Agra City, and more than 91% of samples investigated surpassed the allowable level set for fluoride concentration in potable water 1.5 mg/L, although 9% of the samples were well within the drinking water guidelines (0.5-1.5 mg/L). The hazard quotient (HQ) was obtained to an enormous difference in the exposure dose in infants (1.66-3.91), children (1.87-4.4), and adults (0.92-2.16), correspondingly. The non-carcinogenic HQ values in the group of infants, children, and more than 90% of adults were higher than those of the safety level (i.e., HQ >1). Consequently, the non-carcinogenic risks (HQ level) of fluoride vary from the most to the least: children, infant, and adults, respectively. With 87.41% certainty, the results indicated that the HQ values are between 1 and 3.42. So, infant is the most vulnerable group to fluoride consumption in study area. Uncertainty analysis results indicated that the children group's HQ level was between 1 and 1.90 with 38.48% certainty. To avoid further worsening of the situation as far as health is concerned, remedial actions like alternate sources of water supply and appropriate treatment of water need to be adopted besides required medical attention to affected people.

Time Above All Else: Pharmacodynamic Analysis of Β-Lactams in Critically Ill Patients

Background: Despite the development of new β-lactam agents, gram-negative resistance continues to be an increasing concern in the healthcare setting. The understanding and optimizing antimicrobial pharmacokinetics and pharmacodynamics are essential to enhance activity of appropriate therapy, improve clinical outcomes, and reduce the development of resistance. Methods: A pharmacodynamic analysis was performed for 4 β-lactams (aztreonam, cefepime, piperacillin/tazobactam, and meropenem) and 14 dosage regimens as either intermittent bolus (IB) or prolonged infusion (PI) against 7 gram-negative pathogens: Klebsiella pneumoniae, K. oxytoca, Escherichia coli, Enterobacter cloacae, E. aerogenes, Acinetobacter baumannii, and Pseudomonas aeruginosa. Unit-specific minimum inhibitory concentration (MIC) distribution data were generated using antibiogram data over a decade for 4 intensive care units within our institution: medical ICU, cardiovascular ICU, surgical ICU, and neurosurgical ICU. Published pharmacokinetic parameter estimates in critically ill patients, combined with this MIC distribution data, were utilized to perform Monte Carlo simulations for each antimicrobial regimen. The percentage of time for which the unbound concentration of antibiotic remained above the MIC (ƒT>MIC) was utilized as the pharmacodynamic target for each agent: 40% ƒT>MIC for meropenem, 50% ƒT>MIC for piperacillin/tazobactam, 60% ƒT>MIC for aztreonam, and 70% ƒT>MIC for cefepime. Regimens were modeled using Oracle Crystal Ball software to determine the likelihood of achieving >90% probability of target attainment (PTA). Because resistance rates were significantly higher for P. aeruginosa and A. baumannii, cumulative PTAs for K. pneumoniae, K. oxytoca, E. coli, E. cloacae, and E. aerogenes were analyzed separately to determine the relative PTA for Enterobacterales in each ICU. Results: No intermittent infusion regimens of piperacillin/tazobactam, aztreonam, or cefepime achieved >90% PTA for any organism. Piperacillin/tazobactam 4.5 g infused over 4 hours (PI q6h) and aztreonam 2 g PI q6h failed to achieve adequate PTA for Enterobacterales with only 84% and 85% PTA, respectively. For Enterobacterales, the only regimens to achieve >90% PTA included cefepime 2 g infused over 3 hours (PI q8h) and meropenem 1g IB q8h with 95% and 99% PTA, respectively. Meropenem 2 g PI q8h was the only regimen capable of achieving >90% PTA for both A. baumannii and P. aeruginosa with 97% and 92% PTA, respectively. Conclusions: Although utilization of high doses and prolonged infusions dramatically improve the pharmacodynamics of β-lactam therapy, the only regimen capable of achieving adequate PTA for all organisms analyzed was meropenem 2g PI q8h. To reduce carbapenem use, combination therapy may be considered for critically ill patients receiving aztreonam, cefepime, or piperacillin/tazobactam for empiric treatment of gram-negative infections.Funding: NoDisclosures: None

Effective moisture diffusivity of Sierrathrissaleonensis cracker: optimization, sensitivity and uncertainty analyses

Sierrathrissaleonensis (SL) is a low valued fish in Nigeria because of its small size and availability of fleshy alternatives. Therefore, an alternative utilization of SL is crucial. In this study, SL was used to produce fish cracker (SLC). The SLC, being an intermediate product was dried to achieve moisture stability. During drying process, the influence of drying factors (oven air velocity, sample thickness and oven temperature) on the effective moisture diffusivity (EMD) of SLC was investigated using response surface methodology (RSM) in Design Expert software. The uncertainty of the result and the sensitivity analyses of the drying factors to the variations of EMD were conducted using Monte Carlo simulation in oracle crystal ball (OCB) software. Results showed that fish cracker could be successfully developed with SL. The initial moisture content (d.b) of the SLC was 149.23%. Increment in oven drying temperature and oven air velocity increased the EMD of the SLC while increment in SLC sample thickness decreased the EMD of the SLC. The model developed had an R2 value of 0.9865. Model terms were significant at 5% confidence level. The theoretical optimum drying condition given by RSM showed that SLC should be processed at oven air velocity, SLC sample thickness and oven temperature of 3 m/s, 3 mm and 60°C, respectively to give an EMD of 2.75E-08. The validated SLC optimum drying condition was 2.69E-008. The certainty of achieving the experimental data range was 99.831%. The EMD of SLC drying process had +80.4%, -16.2% and +3.4% sensitivity to oven temperature, sample thickness and air velocity, respectively. These results are useful for the economic utilization of SL and will also assist in energy economics and product standardization during drying processing of SLC.

Analysis based on Monte Carlo simulation: How effective is tigecycline in routine antimicrobial therapy?

This paper aims to assess the efficacy of tigecycline in the treatment of several different infections from a pharmacokinetic/pharmacodynamic (PK/PD) perspective. The minimum inhibitory concentration (MIC) test strip test was used to determine the MICs of clinical isolates of tigecycline. A 5,000-subjects simulation was performed by Crystal Ball software to calculate the probability of achieving the required PK/PD exposure. The use of standard tigecycline dosing is predicted to have a good clinical outcome for patients suffering from complicated skin and skin structure infection (cSSSI) with MICs≤0.25mg×L-1, patients suffering from complicated intra-abdominal infection (cIAI) with MICs≤1mg×L-1, and patients suffering from hospital-acquired pneumonia (HAP) with MICs≤0.5mg×L-1. Generally, Gram-positive bacteria are highly sensitive to tigecycline, while Gram-negative bacteria are less sensitive: for patients with HAP and cIAI, the tolerable outcome was achieved using the standard regimen for most Gram-negative pathogens; the desired outcomes could be obtained for the increased-dose treatment; with increasing dose (100 mg every 12 hours), the average cumulative fractions of response (CFRs) markedly increased from 38.18 to 56.21% for cSSSI patients. When tigecycline, a standard regimen, was used to treat carbapenem-resistant Klebsiella pneumoniae (CRKP) and carbapenem-resistant Enterobacter spp. (CRE) infections, the cumulative response scores were 4.96-66.39% and 13.14-95.18%, respectively, and the CFRs of the increased dose also increased correspondingly. Currently, the standard dose of tigecycline is feasible in the treatment of common bacterial infections, and PK/PD indexes are needed to optimize the regimens for refractory carbapenem-resistant bacterial infections.

A Truck Allocation Optimization Model in Open Pit Mining to Minimize Investment and Transportation Costs

In this research we developed an optimization model to determine truck allocation in open pit mining. The objective function is to minimize a total cost consists of investment and transportation costs. Investment cost is the purchase price of truck in early mining project according to the number of truck needed in each route. The transportation cost consists of fix cost for operators’ wages and variable cost in the form of fuel cost of trucks and shovels. The selection of truck types with different specifications is an important factor in the continuity of materials transportation by considering the costs incurred The model is solved using Oracle Crystal Ball Software for 5000 iterations. The result of optimization shows that Truck 75570 is selected to transport for route 1 and Route 4, Truck 75174 is selected to transport for Route 2, Truck 772 is selected to transport for Route 3, Truck 777F is selected to transport for Route 5, and Truck 7547 is selected to transport for Route 6. The total cost resulted from the optimization is IDR 295,783,073,068.69.

An integrated optimization model of production plan in a large steel manufacturing company

ABSTRACT A large steel company needs to improve its efficiency by integrating the decision making from suppliers to buyers. Therefore, an optimization model is required to determine simultaneously the optimal raw material allocation, liquid steel allocation subject to maintenance schedule, and coils allocation from Hot Strip Mill (HSM) to five sub divisions under HSM. The model is aimed at maximizing total profit with several constraints such as production capacity at each sub division, maintenance cost, and inventory balance. We use the operation research methodology to solve the problem, start with problem definition, model development, find optimal solution, and sensitivity analysis. The model was solved using the Oracle Crystal Ball software. Sensitivity analysis results show that the objective function is sensitive to the changes of maintenance cost, raw material price, and product selling price. The allocation of coil, liquid steel, and the amount of raw material orders are sensitive to the maintenance cost and product selling price.

Aquatic life criteria & human health ambient water quality criteria derivations and probabilistic risk assessments of 7 benzenes in China

The benzenes have attracted worldwide attention due to their high biological toxicity in the environment. In this study, using species sensitivity distribution method to derive the aquatic life criteria of 7 benzenes (carbazole, 1,3-Dichlorobenzene, 1,4-Dichlorobenzene, 1,2,4-Trichlorobenzene, phenol, 2,4-Dichlorophenol and nitrobenzene), then risk quotient method (RQ), potentially affected fraction (PAF) method and joint probability curve (JPC) method were applied for multilevel ecological risk assessment for 7 benzenes in Tai Lake Basin. In addition, the human health ambient water quality criteria (AWQC) of 7 benzenes were derived according to USEPA guidelines, and the probability distributions of human health AWQC for 7 benzenes in China were simulated by Monte Carlo simulation combined with crystal ball software. Finally, the health risks of 7 benzenes in Tai Lake were assessed by RQ method assisted by Monte Carlo simulation. The results showed that nitrobenzene had the maximum aquatic life criteria value, followed by phenol, chlorobenzenes, 2,4-Dichlorophenol and carbazole. All recommended human health AWQC values of 7 benzenes were found at a position of 27th-55th percentiles in the output criteria distributions, indicating that recommended national human health AWQC values could provide effective protection for most of the population in China. Furthermore, the consumption of aquatic products was found to be the most influential parameter of human health AWQC for benzenes with higher Kow values. The risk assessments showed that noncarcinogenic 2,4-Dichlorophenol had potential ecological risk, carcinogenic carbazole and 1,2,4-Trichlorobenzene had significant human health risk in Tai Lake.

Techno-economic and uncertainty analyses of heat- and ultrasound-assisted extraction technologies for the production of crude anthocyanins powder from Hibiscus sabdariffa calyx

This study designed, techno-economically analyzed and compared the heat-assisted extraction (HAE)- and ultrasound-assisted extraction (UAE)-technology-based processes (HAE-tBP and UAE-tBP) for the production of crude anthocyanins powder (CAnysP) from Hibiscus sabdariffa calyx (HSC) with the assistance of SuperPro Designer software. Both the base cases and industrial setups of 600 L extractor capacities for HAE- and UAE-tBPs were analyzed and compared. When building the process flowsheets, peculiarities of the technicalities of both HAE and UAE extractors were taken into consideration. Materials and energy demands, production costs and unit production cost (UPC) of CAnysP were the parameters used for process analysis. Uncertainty and sensitivity analyses were conducted for the process with least CAnysP UPC using Monte Carlo simulations in Oracle Crystal Ball software. The HAE-tBP recorded the highest number of batches of 5278 per annum. HSC of 15.551 kg was required to produce 7.433 and 10.022 kg/batch CAnysP by 600 L extractor setup of HAE- and UAE-tBPs, respectively. The UAE-tBP achieved lower CAnysP UPC (164.28 US$/kg) compared with HAE-tBP (176.31 US$/kg) with 80.08% certainty. Out of the variables considered for sensitivity analysis of UAE-tBP UPC, ultrasound treatment time contributed the highest (+62%), while anthocyanins recovery contributed the least (+0.2%) to the variance in UPC.

Health risk assessment and heavy metal accumulation in fish species (Clarias gariepinus and Sarotherodon melanotheron) from industrially polluted Ogun and Eleyele Rivers, Nigeria.

Ogun and Eleyele Rivers are in the Western part of Nigeria with a potential risk of heavy metal pollution because of many industrial wastes channeling through their courses. Therefore, in this study, the concentration of heavy metals and the possible human health risk of consuming Clarias gariepinus and Sarotherodon melanotheron collected from industrially polluted Ogun and Eleyele Rivers in Nigeria were evaluated. The concentration of arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), manganese (Mn), nickel (Ni), and lead (Pb) in tissues (gill, muscle, and liver) of fish was measured using Atomic Absorption Spectroscopy (AAS) and compared with the maximum permissible. The Estimated Daily Intake (EDI), Targeted Hazard Quotient (THQ), and Carcinogenic Risk (CR) of the metals were estimated for the determination of human health risk. Probabilistic predictions of the health risk were performed with Oracle Crystal Ball software. Results of this study showed that the dry weight concentrations of the metals in the gills, liver, and muscle of the two fish species from the two sites were well below the permissible limits set by the joint FAO/WHO Expert Committee. Only the EDI for arsenic in gills of C. gariepinus obtained from the Ogun River exceeded the set limit. The THQ was >1 for As in the gills and liver of C. gariepinus and S. melanotheron obtained from the Ogun river suggesting non-carcinogenic risk to the consumers. The carcinogenic risk above 10-6 obtained for As, Cd, and Ni in the tissues of the two fish species suggested cancer risk to the consumers of fish from the two rivers. Consequent to our observation, consumption of fish from the study site presents some public health concerns. Therefore, this study advises routine heavy metal monitoring of fish along these rivers to implement regulatory standards by the government environmental health management agencies.

Improving the assessment of the environmental and economic efficiency of measures

The purpose of the study is to improve methods for improving the regulatory and methodological framework for assessing the environmental and economic effectiveness of land reclamation investment projects. The research methodology is based on the Monte Carlo method, which corresponds to international standards, the theory and algorithms of innovative methods for determining risks, as well as the ability to provide the user with information about the content of risk assessment operations and ensure that their preferences are taken into account in the calculation process. Currently, many tools have been developed for automating risk analysis procedures, including those performed by the Monte Carlo method, which are described in various studies with varying degrees of completeness. The analysis of priority methods of assessing the risks of achieving the projected economic indicators of project solutions is performed and the prospects of the simulation method for practical use in the field of land reclamation are shown. The results of the risk assessment of environmental and economic efficiency of anti-filtration coatings of hydraulic structures of irrigation systems performed by the Monte Carlo method in the environment of the Crystal Ball software product are presented, and the need to improve the reliability of the predicted results of the effectiveness of the designed measures is established. Future research is risk assessment of profitability of the designed activities promote the development of existing and formation of new theories to justify the feasibility of implementation of reclamation investment projects.

Health risk assessment of polycyclic aromatic hydrocarbons via dietary intake of leafy vegetables

ABSTRACT The 16 US-EPA priority polycyclic aromatic hydrocarbons (PAHs) can reach to potentially hazardous levels in leafy vegetables as studies suggest. In this study, the 16 PAHs were quantified in samples of lettuce, cabbage, celery and spinach collected from Tehran central fruit and vegetable market in summer and winter using gas chromatography mass spectrometry (GC-MS). The results indicated the dominance of low molecular weight PAHs (LPAHs) in all vegetables. With respect to total mean concentration, the vegetables were ordered as follows: lettuce (51.61 µg/kg) > cabbage (28.13 µg/kg)> spinach (24.85 µg/kg) > celery (9.98 µg/kg). Isomeric ratios and principal component analysis (PCA) suggested diesel and gasoline vehicles, petroleum and coke ovens as the sources of pollution. No statistically significant difference was found between summer and winter regarding the total mean concentrations of 16 PAHs in the vegetables. The estimated combined lifetime average daily dose (LADD) was 3.36E-6 (mg/kg/day) and the estimated excess lifetime cancer risk (ELCR) upper confidence limit (P95%), using Monte Carlo Simulation (MCS) in Oracle Crystal Ball software, was 3.88E-5, indicating low cancer risk. Assessment of target hazard quotient (HQ) showed no possible adverse health effect. Sensitivity analysis showed exposure duration, Benzo[a]pyrene equivalent concentration (BaPeq) and body weight (BW) as the most influential parameters.

Investigation of seasonal variation and probabilistic risk assessment of BTEX emission in municipal solid waste transfer station

ABSTRACT The municipal solid waste transfer stations (MSWTSs) affects both the environment and human health. The present study aimed to investigatethe Concentrations of BTEX (benzene, toluene, ethylbenzene and xylene) the important group of VOCs, in the ambient air of municipal solid waste transfer station (MSWTS) of Hamadan city and to estimate stochastic cancer and non-cancer risk for inhalation exposure to BTEX compounds by Crystal Ball software. The average produced amount of solid waste in Hamadan in 2109 has been estimated to be over 150,000 tons. The solid waste mostly consisted of a complex mixture containing kitchen/food waste (56.85%), consumed plastics (11.33%), paper (2.88%), glass (1.20%) and other materials (27.74%), which collected from households and commercial areas. The findings revealed that BETX concentration in the ambient air of MSWTS in summer is higher as compared to the spring season. The 95% percentile lifetime cancer risk (LCR) value for benzene was estimated to be 8 × 10−4, which is higher than the recommended standards (10−6). The obtained 95% percentile hazard quotient (HQ) value for xylene was found to be higher than the suggested value of 1. Also, the total cumulative value of the 95th percentile HQs for (toluene, ethylbenzene and xylene) TEX was obtained to be about 3.39, which is higher than the acceptable value of HQ. The results of sensitivity analysis for LCR of benzene and HQs of TEX disclosed that the parameter of pollutants concentration has the highest effect on risk’s variance. According to the values of cancer and non-cancer risk assessment, that were higher than safe levels and the major contribution of pollutant concentration in sensitivity analysis, it is concluded that the implementation and development of technical and engineering control measures must be regarded as an essential target to reduce workers exposure to the pollutants and to decrease the concentration of the pollutant in the ambient air of MSWTS.

A high spatiotemporal resolution anthropogenic VOC emission inventory for Qingdao City in 2016 and its ozone formation potential analysis

Accurate and gridded emission inventories are crucial for better air quality modeling and air pollution policy making. As the economic center of the Shandong province and part of the first batch of open coastal cities in China, Qingdao has been frequently plagued by volatile organic compound (VOC) pollution along with its rapid economic development and urbanization in recent years. In this study, a high spatiotemporal resolution VOC emission inventory for Qingdao was established for the year 2016 using updated source-specific emission factors and the latest activity data for different sources. The anthropogenic sources considered in this study are classified into seven major sources and 46 subcategories. The results indicated that a total of 151.5 kt of VOCs were emitted in Qingdao in 2016. The three largest emission sources, industrial process, on-road mobile, and solvent use sources accounted for 49.9% 20.1%, and 14.1% of the total VOC emissions, respectively. Spatially, the Huangdao District (57.9 kt), the Chengyang District (15.4 kt), and Pingdu City (15.1 kt) were the top three emitters of VOCs. The high concentration of VOCs was mainly distributed in the central areas of Qingdao city and the emissions distribution was highly consistent with its road network. The maximum monthly VOC emissions occurred in June (14.4 kt) and the minimum monthly VOC emissions occurred mainly in February (9.5 kt). The uncertainties in the emission inventory were quantified using a Monte Carlo simulation provided by the Oracle Crystal Ball software. There exist relatively high uncertainties in the on-road mobile (-84.79%, 252.07%), biomass burning (-65.38%, 134.77%) and industrial process (-36.08%, 133.62%) sources. For the complicated species and different reaction rates of ozone formation, the control of the amount of VOCs emitted and the highly reactive VOCs are equally important. Based on the emissions of individual VOC species and the corresponding maximum incremental reactivity (MIR), the ozone formation potential (OFP) profiles of Qingdao City were constructed. The results indicated that alkenes/alkynes and aromatics contributed the most to the OFP and that m/p-xylene, ethylene, propylene, formaldehyde, toluene, trans-2-butene, cis-2-butene, 1-butene, o-xylene, and 1-pentene were the top 10 individual VOC species contributing to the OFP. The contribution of industrial process and on-road mobile sources accounted for 37.5% and 24.5% of the total OFP in Qingdao City, respectively. Both the large VOC emission and OFP indicate that the focus of VOC emission control should be on industrial process and on-road mobile sources in Qingdao City.

Aplicação do método de Monte Carlo para previsão do índice de Overall Equipment Effectiveness de uma máquina produtora de celulose

A aplicação da simulação nas organizações traz diversas vantagens, desde um entendimento dos seus sistemas e processos, até perspectivas quanto às estratégias e próximos passos, pois permite projetar cenários e desenvolver planos de ação, a baixo custo. Nesse contexto, identificou-se a oportunidade de continuar um estudo referente ao indicador de eficiência global do equipamento, Overall Equipment Effectiveness (OEE), em uma indústria produtora de papel e celulose. Portanto, foram realizadas simulações de Monte Carlo, a partir de dados históricos de natureza quantitativa, referente ao funcionamento de uma máquina - que apresenta OEE médio atual de 65.08% e capacidade teórica para produzir 624 toneladas de celulose em 24 horas de operação. O objetivo foi verificar a viabilidade deste equipamento atingir o nível de 85% no índice de OEE, considerado de Classe Mundial, e entender quais variáveis e parâmetros mais impactam a eficiência deste indicador, por meio de simulações de Monte Carlo, realizadas no software Crystal Ball. Como resultado, foram realizadas 50.000 iterações e constatou-se que a probabilidade do equipamento atingir um OEE de nível mundial foi de apenas 0.009%. Verificou-se também, a partir do gráfico de sensibilidade, que os parâmetros que mais interferem na eficiência desse índice são o Desempenho (54.7%) e a Disponibilidade (31.9%) da máquina. Conclui-se que, a partir da geração de um volume robusto de dados, a simulação permitiu avaliar a interação de diferentes variáveis presentes na linha de produção e seus impactos em indicadores relevantes da empresa, sem a necessidade de realizar qualquer alteração prévia no ambiente de trabalho. Portanto, pode ser aplicada como importante ferramenta para estudos de viabilidade, análise de performance e tomada de decisões nas empresas.

Cost-effectiveness of CHOP in treating DLBCL in Malawi.

6644 Background: DLBCL is common in Africa, and often curable, but treatment costs and cost-effectiveness are key considerations. WHO defines extremely cost-effective interventions as having an incremental cost-effectiveness ratio (ICER) < GDP per capita. Methods: We used a decision tree model to conduct a cost-effectiveness and budget impact analysis from a health systems perspective in Malawi (2017 GDP per capita $340). Comparisons were made between CHOP vs. palliative care with diagnosis (PC+D), and palliative care without diagnosis (PC-D). Microcosting and clinical outcomes were derived from published prospective data. Costs reflect treatment and 2 years of follow-up. Outcomes reflect a lifetime time horizon. Life expectancies were derived from UNdata, and disability-adjusted life year (DALY) weights from the Global Burden of Disease Study. Costs were analyzed in 2017 US $, and costs and outcomes were discounted at 3% annually. Annual estimates for new DLBCL cases (n=161) were used as input incidence. Probablistic sensitivity analysis was conducted using Crystal Ball software over 1000 simulations. Results: For the base case, the ICER of CHOP versus PC+D is $150/DALY averted, and versus PC-D is $200/DALY averted (Table). The ICER was stable across a wide range of sensitivity analyses. The ICER varied most across the range of progression-free survival estimates ($117-209), and range of costs for CHOP plus follow-up ($71-308). CHOP was extremely cost-effective by the WHO definition in 99% of simulations versus PC+D, and 94% of simulations versus PC-D. In the base case, total annual cost of DLBCL treatment with CHOP in Malawi was $306,221. Conclusions: This is one of the first rigorous cost-effectiveness and budget impact analyses for cancer treatment in a low-income country. CHOP is extremely cost-effective compared to palliative care, with ~$300,000 needed annually to treat all DLBCL cases in Malawi. These findings merit external validation, and support continued regional investments in cancer care. [Table: see text]

Durability of Concrete Bridge Structure under Marine Environment

ABSTRACT Cai, J.; Dong, F., and Luo, Z., 2018. Durability of concrete bridge structure under marine environment. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 429–435. Coconut Creek (Florida), ISSN 0749-0208. According to the known erosion mechanism of chloride ion on concrete structure and the mechanism of steel corrosion, the evaluation index system and fuzzy comprehensive evaluation factor set for studying the durability of concrete bridge structure are established, and the durability evaluation model of concrete bridge structure under the environment of chloride ion erosion. Taking into account the uncertainty of the main parameters in the life assessment model, based on the Monte Carlo principle, the random simulation of concrete members is carried out by using Crystal Ball software. The results of random simulation show that the thickness of protective layer and the concentration of chloride ion are the imp...

Simulation Model for Stock of Building Materials Developed with Crystal Ball Software Use

The article presents a simulation model of the inventory with two variables developed using the Crystal Ball software. This model is designed for the purpose of optimization of logistics processes related to the organization of supply and storage of construction materials used in the production process. The result of the model, we get information about what reserve should be basic to the whole process took place without interference. Not always, however, it is possible to create initial stock of this size. Using the Crystal Ball software, it can be obtained information, what is the probability to avoid downtime for different levels of initial reserves. The model is based on the classical model developed by Jaworski Professor of the Warsaw University of Technology. In the new model two variables will be considered. The first variable is the amount of depreciation. In the classical model it is described discreetly. Based on historical data, determines the probability with which will be observed the consumption plan and the probability of default and excess of norm of consumption of this material. The second variable take into account the amount of planned delivery. In the same way as in the case of the size of the depreciation in the classical model this variable was described discreetly. As before, the author recommends a definition based on historical data probability of compliance with the required value of delivery probability and delivery more or less than planned. In the presented model we also consider the possibility of describing random variables using other than the discrete graphics and the empirical probabilities. This procedure allows for the approximation of modelling methods for people who do not have the appropriate set of historical data and would like to use it to minimize the risk of organizational problems. The article shows what results are achieved through the use of the software Crystal Ball, and how they can be used in the organization of the construction investment process.

Quantifying the uncertainty in the ultimate recoverable oil reserves using the Monte Carlo simulation techniques from ‘OWA’ Marginal Field, Onshore Niger Delta, Nigeria

A review on the development of marginal oil fields in Nigeria has now become an important strategic issue if it is to remain amongst the top producers in the global market, and these fields are vast, available all over the Niger Delta. One of the factors that makes a field marginal is the size of its reserves. Stochastic estimation gives a certainty in terms of the possible number of outcomes within the range of input parameters. In this work, four (4) deviated wells and 3D seismic volume (362 inlines and 401 traces) were interpreted for the evaluation of the field. The petrophysical evaluations were interpreted using the Power Log software and the Seismic, Geographix and Petrel softwares. Stochastic reserve estimation was done using Monte Carlo sampling techniques and subjected to uncertainty quantification using the Crystal Ball software by varying distributions and measuring sensitivity impact on the overall reserves. The production profile was predicted based on some assumptions and history matching which result in the overall Expected Ultimate Recovery (EUR). The petrophysical analysis shows the reservoirs to be within the unconsolidated continental Benin Formation denoted as ‘Intra-Benin’ sands, an unconventional reservoir as supposed the normal reservoir rocks within the Agbada Formation. This indicated high porosity (0.28), water resistivity (7 Ω∙m), and water saturation and also inferred Heavy Oil (low API). Nine hydrocarbon sands were identified but only three (B1, D and E), representing shallow, mid and deep reservoirs were further evaluated. 1P and 2P reserve estimates were 4.8 MMBO and 5.7 MMBO for B1; 15.2 MMMscf and 16.4 MMMscf for D; 8.4 MMMscf and 8.8 MMMscf for E respectively. The Monte Carlo simulation of 1,000,000 trials with mainly triangular distribution assumption generated P10, P50, P90 were 6.5 MMBO, 5.6 MMBO and 4.4 MMBO for B1; 17.5 MMMscf, 13.7 MMMscf and 10.8 MMMscf for D; 10.4 MMMscf, 8 MMMscf and 6.1 MMMscf for E respectively. The sensitivity impact of the input parameters were estimated and ranked, and the coefficient of variability ranges within 15% to 20% for the reservoirs indicating that there is a very low level uncertainty of reserve estimation around the P10, P50 and P90 percentiles which could be positive for investment decisions. ‘OWA’ marginal field reflects a typical low reserve (EUR) category found within the Niger Delta basin.

Life cycle assessment and optimization analysis of different LNG usage scenarios

This paper aims to compare the environmental impacts of LNG in different life cycle stages and for various usages by applying life cycle assessment (LCA). According to different usage processes, we set three scenarios including S1-hydrogen production, S2-electricity generation, and S3-vehicle fuel to evaluate their environmental impacts. Furthermore, in order to satisfy better city development, an optimization analysis was made to identify the optimal distribution structure of LNG. The environmental impact analysis of LNG was conducted using life cycle assessment and CML2001 method. LCA was performed based on the ISO 14040 standard using GaBi 5.0 software. Four impact categories (i.e., global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), and photochemical ozone creation potential (POCP)) were considered. Sensitivity analysis was also made by means of GaBi 5.0 software. Crystal Ball software was applied to make the optimization analysis for different LNG usage scenarios. The minimum environmental impact factor was taken as the objective function to confirm the optimal distribution structure of LNG. The LCA results indicate that the environmental impacts of the gasification and usage stages far outweigh that of the transportation stage, and the highest environmental impact category for each scenario is GWP. The largest contribution factor to GWP of S1 is the production supply of imported electricity, whereas the largest contribution factor to GWP of S2 and S3 is the emissions. The optimization analysis indicate that when imported LNG is allocated 25% for hydrogen production, 73% for electricity generation and 2% for vehicle fuel, the GWP and cost of the total LNG usage are both minimum. Environmental analysis on different LNG usage scenarios allows the identification and selection of comprehensive LNG usage plans with the minimum environment impacts and lowest cost. For different LNG usage scenarios, the GWP of LNG used for vehicle fuel is the highest and for hydrogen production is the lowest. The production supply of imported electricity and the emissions are the two largest contribution factors to LCA results as well as the sensitivity analysis results of the three scenarios. The optimization analysis method and results can provide technology reference for scientific urban planning of LNG application and allocation.

Exploring the uncertainty in capacity estimation at roundabouts

PurposeIn gap-acceptance theory the critical and the follow-up headways have a significant role in determining roundabout entry capacities which in turn depend on circulating flow rates under a specified arrival headway distribution. Calculation considers single mean values of the gap-acceptance parameters, neglecting the inherent variations in these random variables and providing a single value of entry capacity. The purpose of this paper is to derive the entry capacity distribution which accounts for the variations of the contributing (random) variables and suggest how to consider this issue in the operational analysis of the roundabouts.MethodsWe performed a Monte Carlo simulation to get the distribution of entry capacity and found Crystal Ball software effective for performing the random sampling from the probability density functions of each contributing parameter. A steady-state model of capacity was used for performing many runs; in each run, the values of each contributing parameter were randomly drawn from the corresponding distributions.ResultsThe paper presents the first simulations and the entry capacity distributions at roundabouts, once the probability distributions of the headways were assumed. The results of the analysis were expressed probabilistically, meaning that the probability distributions of capacity rather than the simple point estimates were obtained.ConclusionsComparing the capacity values based on a meta-analytic estimation of critical and follow-up headways and the capacity functions based on the probability distributions of the model parameters, more insights in developing an appropriate approach to capacity estimation at roundabouts can be gained.