Erroneous Calculations Research Articles

High throughput quantification of oil degradation using high-performance thin layer chromatography

India, the largest consumer of vegetable oil, generates massive amounts of wastewater during its production, adversely affecting the aquatic ecosystem. Various methods are used to degrade vegetable oils. Conventionally, oil degradation was quantified by measuring a sample’s end products, such as free fatty acid (FFA) or glycerol. None of these techniques measures intermediate compounds (monoglycerides or diglycerides), which leads to erroneous oil degradation calculations. We propose a high-performance thin-layer chromatography (HPTLC) based method to quantify the percentage degradation of soybean oil. The mobile phase consists of n-hexane, ethyl acetate, acetic acid (9:1:0.1, v/v/v) and spots scanned at 196 nm. Soybean oil in water (1%, v/v) degraded using immobilized lipase at 37 °C temperature, pH 7, and 180 rpm for 6 h. The change of bonds in FTIR qualitatively confirms the degradation of oil. The proposed method was validated by comparing the quantity of FFA obtained from the HPTLC chromatogram (22.62 ± 0.07%, w/w) with the data calculated from acid value (21.98 ± 0.56%, w/w). The percentage degradation was calculated as 45.67 ± 0.67 (w/w). The present study shows that the developed method is a consistent, precise, reproducible, accurate, and rapid analytical technique for quantifying degraded oil in water.

The Development of an IoT-Based Palm Solid Waste Counting System for Empty Fruit Bunches in the Palm Oil Industry

The recent application of palm empty fruit bunches as solid waste directly on soil or as organic fertilizer has enhanced palm farms. Moreover, the co-products of this palm oil mill constitute a dependable metric for assessing mill processing performance, specifically regarding quantity and weight. The quantity of palm empty fruit bunches is usually ascertained through manual counting using a hand counter during processing. The imprecision in calculating palm empty fruit bunches is a limitation of this method, as operators sometimes perform erroneous calculations, overlook quantities, and produce contradictory results for mill management. To address this issue, the sector requires enhanced execution of a monitoring and counting system methodology. The aim of this community service project is to create an empty fruit bunches count station using an IoTbased palm solid waste counting system for use in palm mills. The Ministry of Industry - Politeknik Teknologi Kimia Industri (PTKI) Medan will engage in and oversee the advancement of Industry 4.0 within the industrial sector. The initiative was executed at Tanah Gambus Estate in Batubara Regency, North Sumatra. Assistance was provided by a palm mill partner associated with PT. Socfin Indonesia. The implementation of the empty fruit bunches palm oil counting system was conducted efficiently, facilitating optimal operations, real–time online monitoring, uninterrupted functionality exceeding 24 hours daily, swift assessment of the empty fruit bunches volume, immediate identification of traditional counting inaccuracies by operators and management, and its station provides benefits to the palm industry.

Interpretation of the Calculation Problem of Power Loss in Long-distance Transmission Lines——Starting from the Serious Errors in Calculation Methods in High School Physics Textbooks

This article points out the erroneous calculations of power loss and voltage loss in long-distance transmission lines in high school physics textbooks; Based on the basic circuit structure of long-distance power transmission, provide a series of correct functional relationships between power transmission power, line loss power and loss voltage, transmission line current and transformer ratio, load resistance, transmission line resistance, and the relationship between power supply voltage and transmission voltage, and discuss related issues based on these functional relationships.

Evaluation of stopping power ratio of artificial breast implants for carbon-ion radiotherapy.

The number of patients requiring breast reconstruction with artificial implants has been increasing, and so is the use of carbon-ion radiotherapy (CIRT). Consequently, a growing number of patients with artificial breast implants are expected to undergo CIRT. Because artificial breasts are composed of a silicone polymer gel with a silicon-oxygen backbone, which differs significantly from human tissues, the stopping power ratio for carbon beams cannot be accurately converted from CT values using standard CT-to-stopping power ratio tables (CT-SP tables). Incorrect stopping power ratios can lead to significant problems in CIRT, including erroneous calculations of carbon beam range. To address this, we measured the CT values and stopping power ratios of three commercial artificial breasts using a 380MeV/u carbon beam. Our results revealed significant deviations from the CT-SP table values. For instance, calculations for treating lung cancer with incorrect stopping power ratios resulted in errors of approximately 5mm in range calculations, adversely affecting dose distribution to the target. Although further studies with various products are needed, it is crucial to conduct thorough patient consultations and develop treatment plans using accurate stopping power ratios.

Fast Optimization of the Net Present Value of Unconventional Wells Using Rapid Rate-Transient Analysis

Summary Decline-curve analysis (DCA) is the industry standard to predict hydrocarbon production to then estimate the net present value (NPV) of unconventional wells. Conventional DCA assumes the flowing bottomhole pressure (BHP) is constant. This is an unrealistic assumption for many unconventional wells that can lead to incorrect estimates of ultimate recovery and thus erroneous NPV calculations. This work illustrates the application of a novel technique that combines variable BHP conditions with decline-curve models [Rapid rate-transient analysis (RTA)] to estimate the NPV and select the optimal cluster spacing and number of fractures for a given well. We compare the results of DCA and Rapid RTA to estimate and optimize the cluster spacing for a tight oil and shale gas well. The Rapid RTA results show marked differences in terms of the shape and the optimal value of the NPV function from the simpler DCA method. For the two cases illustrated, DCA results are a direct consequence of the rate-time analysis failing to correctly detect the onset of boundary-dominated flow (BDF). In contrast, Rapid RTA correctly detects the onset of BDF and presents a defined maximum value of the NPV vs. cluster spacing (number of fractures) function. This optimal value is a trade-off between the fracture treatment cost, the speed of recovery of hydrocarbons, and the value of money with time (discount rate). The major contribution of this work is the implementation of the Rapid RTA technique allowing fast computation of pressure-rate-time analysis and NPV calculations with computational times comparable with DCA for optimizing fracture cluster spacing and the total number of fractures of unconventional wells. We have developed a web-based application to give readers a hands-on experience of this new technique and to analyze and optimize the NPV of unconventional wells.

Microfluidic flow sensor based on chronoamperometric measurements in a microchannel

Microfluidics explores the fluid behavior at micron scale and is therefore suited to applications that need precise manipulation of fluids at small length or volume scales. In a span of over two decades, microfluidics has become an essential tool for modern genome sequencing platforms, single-cell analysis and common diagnostic tests. Despite many successful applications, the field has various challenges: Fabrication processes are yet to transition to commercial materials, microfluidic systems are reliant on skilled operators, and supporting equipment. Technological innovations in automation are needed to enable easy to use, completely on-chip microfluidic systems. Sensors are a critical component of any automated system. Fluid and flow properties such as flow rate, pressure, temperature, viscosity are critical to applications in drug development, and material/chemical synthesis. The flow rate (μL/min or nL/min) predictions based on external (off-chip) flow measurements can lead to erroneous calculations. The present work explores a technique based on chronoamperometry to measure flow rates inside a microchannel. Chronoamperometry based redox cycling of aqueous NaCl was performed by using interdigitated electrodes (IDE). The sensor measures current transients (which are modulated by the flow rate of the solution) effected by redox reactions on surface of the electrodes. The sensor demonstrated a sensitivity of 0.016 (μL/min)−1 change in charge transfer per unit change in flow rate and 3σ resolution of 9.3 μL/min. The calibration curve is linear in the range 0 – 200 μL/min, with a limit of detection (LoD) of 5 μL/min, making it suitable for various microfluidics applications.

Comments on the erroneous calculations presented in the paper on “Dielectric and impedance spectroscopy of barium orthovanadate ceramics, J. Mater. Sci.: Mater. Electron. 24, 1608 (2013)”

Comments on the erroneous calculations presented in the paper on “Dielectric and impedance spectroscopy of barium orthovanadate ceramics, J. Mater. Sci.: Mater. Electron. 24, 1608 (2013)”

Чернышевский и Наполеон III

Introduction. The image of Napoleon III in philosophical thinking of Chernyshevsky is important for the characterization of ideological struggle in the nineteenth century. Theoretical analysis. From his student years, Chernyshevsky followed the political career of Louis Bonaparte, noted his successes and personal traits. During the Second Empire in France, Chernyshevsky criticized Bonapartism, put forward an explanation of the reasons for its temporary triumph. He mentioned the worship of the peasantry before the glory combined with a famous name, the fear of anarchy and the erroneous calculations of the warring camps. The article shows how Chernyshevsky’s analysis of Bonapartism is related to the theoretical principles proclaimed in his main philosophical works. Just as Chernyshevsky himself, Napoleon III tried to rely on the theory of progress, but at the same time he assigned an important role to the government in the process of moving of society towards a better future. His ideal is an empire symbolizing order and power. Conclusion. In fact, Chernyshevsky and Napoleon III defended two diametrically opposed concepts of progress. They disagreed, first of all, on the question of how the true interests of the nation should be understood. In the question of the vitality of the empire, Chernyshevsky obviously turned out to be right.

Are Si–C bonds formed in the environment and/or in technical microbiological systems?

Organosiloxanes are industrially produced worldwide in millions of tons per annum and are widely used by industry, professionals, and consumers. Some of these compounds are PBT (persistent, biaccumulative and toxic) or vPvB (very persistent and very bioaccumulative). If organosiloxanes react at all in the environment, Si–O bonds are hydrolyzed or Si–C bonds are oxidatively cleaved, to result finally in silica and carbon dioxide. In strong contrast and very unexpectedly, recently formation of new Si–CH3 bonds from siloxanes and methane by the action of microorganisms under mild ambient conditions was proposed (in landfills or digesters) and even reported (in a biotrickling filter, 30 °C). This is very surprising in view of the harsh conditions required in industrial Si–CH3 synthesis. Here, we scrutinized the pertinent papers, with the result that evidence put forward for Si–C bond formation from siloxanes and methane in technical microbiological systems is invalid, suggesting such reactions will not occur in the environment where they are even less favored by conditions. The claim of such reactions followed from erroneous calculations and misinterpretation of experimental results. We propose an alternative explanation of the experimental observations, i.e., the putative observation of such reactions was presumably due to confusion of two compounds, hexamethyldisiloxane and dimethylsilanediol, that elute at similar retention times from standard GC columns.

A Denoising Autoencoder for Improved Kikuchi Pattern Quality and Indexing in Electron Backscatter Diffraction

The rapid collection and indexing of electron diffraction patterns as produced via electron backscatter diffraction (EBSD) has enabled crystallographic orientation and structural determination, as well as additional property-determining strain and dislocation density information with increasing speed, resolution, and efficiency. Pattern indexing quality is reliant on the noise of the collected electron diffraction patterns, which is often convoluted by sample preparation and data collection parameters. EBSD acquisition is sensitive to many factors and thus can result in low confidence index (CI), poor image quality (IQ), and improper minimization of fit, which can result in noisy datasets and misrepresent the microstructure. In an attempt to enable both higher speed EBSD data collection and enable greater orientation fit accuracy with noisy datasets, an image denoising autoencoder was implemented to improve pattern quality. We show that EBSD data processed through the autoencoder results in a higher CI, IQ, and a more accurate degree of fit. In addition, using denoised datasets in HR-EBSD cross correlative strain analysis can result in reduced phantom strain from erroneous calculations due to the increased indexing accuracy and improved correspondence between collected and simulated patterns.

Retracted] CtBP1 interacts with SOX2 to promote the growth, migration and invasion of lung adenocarcinoma.

Following the publication of this paper, it was drawn to the Editors' attention by a concerned reader that, for the western blots showing the CtBP1 and SOX2 bands in Fig.5C on p.74, the data were in fact the same, but flipped horizontally; moreover, two pairs of overlapping data panels were identified comparing between the cell invasion and assay data images shown in Figs.3E and 6C, such that these were likely to have been derived from the same original sources even though they were intended to show the results from differently performed experiments; similarly, the 'shSOX2/24h' and 'shCtBP1/24 h' data panels in Fig.6B showing the results of differently performed scratch‑wound assay experiments appeared to be overlapping, albeit with one of the panels being slightly rotated relative to the other. Finally, there were erroneous calculations included for the CtBP1 expression data shown in TableIII. Given the large number of apparent errors that were made during the assembly of various of the figures and TableIII in this paper, the Editor of OncologyReports has decided that this paper should be retracted from the Journal due to an overall lack of confidence in the presented data. After contacting the authors, they accepted the decision to retract this paper. The Editor apologizes to the readership for any inconvenience caused. [Oncology Reports 42: 67‑78, 2019; DOI: 10.3892/or.2019.7142].

Systematic kinetic study of magnesium production using magnesium oxide and carbonic materials at different temperatures

The main goal of this study was to determine the industrially best reductant for reduction of magnesium oxide to magnesium with wood charcoal and petroleum coke (petcoke) each in molar ratio 1:1 and 1:2 (oxidant:reductant) at high temperatures. In this study, a new and reliable combination of mathematical modeling and discrete numerical optimization theory by presenting 18 “mathematical filters” not relying only on statistical quantities of fitting (contrary to many similar researches) was introduced. The purpose of these filters was the determination of correct kinetic equation and therefore, the corresponding rate coefficient from among 18 equations most used at present in the challenging field of solid state chemical kinetics. With assistance of a new and fundamental mathematical function and the obtained values of rate coefficients, the function of rate coefficient in temperature was attained. The activation energy was then calculated as a function of temperature using the general definition of activation energy and the determined function for rate coefficient. The comparison between different reducing agents in the different conditions and with relevant previous study was accomplished to determine the best reducing agent from industry standpoint. Also, the areas under experimental data were calculated numerically and utilized for method validation and comparison. It turned out finally that relying only on fitting quantities in the solid state chemical kinetics can readily lead to wrong conclusions about the correct kinetic equation and about the most suitable reducing agent. It is obvious that the erroneous calculations and wrong decisions in the laboratory scale become significant and paramount in industry and this reveals the significance of rigorous mathematical analysis.Graphical abstract

Evaluating evapotranspiration using data mining instead of physical-based model in remote sensing

Precise calculations for determining the water requirements of plants and the extent of evapotranspiration are crucial in determining the volume of water consumed for plant production. In order to estimate evapotranspiration over an extended area, different remote sensing algorithms require numerous climatological variables; however, climatological variable measurements cover only limited areas thus resulting into erroneous calculations over extended areas. The exploiting of both data mining and remote sensing technologies allows for the modeling of the evapotranspiration process. In this research, the physical-based SEBAL evapotranspiration algorithm was remodeled using M5 decision tree equations in GIS. The input variables of the M5 decision tree consisted of Albedo, emissivity, and Normalized Difference Water Index (NDWI) which were defined as absorbed light, transformed light, and plant moisture, respectively. After extracting the best equations in the M5 decision tree model for 8 April 2019, these equations were modeled in GIS using python scripts for 8 April 2019 and 3 April 2020, respectively. The calculated correlation coefficient (R2), mean absolute error (MAE), and root mean squared error (RMSE) for 8 April 2019 were 0.92, 0.54, and 0.42, respectively, and for 3 April 2020 were 0.95, 0.31, and 0.23 in order. Moreover, for the further evaluation of the model, a sensitivity analysis and an uncertainty analysis were carried out. The analysis revealed that evapotranspiration is more sensitive to Albedo than the two other model inputs, and when applying data mining techniques instead of SEBAL, the estimation of evapotranspiration has a lower accuracy.

Economic behavior and behavioral economics at times of COVID-19 pandemic

I am a behavioral economist, who is interested in both behavioral sciences and economic behavior. By the term “economic behavior” I refer to the calculative reasoned domain of economic analysis, whereas by “behavioral economics” I address aspects of human feelings, emotions and everything that is not captured by the “rational” paradigm. Evidently, erroneous calculations, as well as unhinged sentiments lead to economic losses, and every change in the economics of the world has both calculative and behavioral sides to it. In what follows, we examine these two sides of behavior in relation to the COVID-19 pandemic by drawing on contemporaneous data, forecasts, and images. Each side of behavior reveals distinctive insights, and intriguingly, not all outcomes count as loss. As we face this crisis, there is a clear environmental gain that we would be smart to preserve post pandemic.

Restoration of multiphase salt tectonic deformation using passive strain markers

AbstractSeveral salt basins globally have been subject to multiphase deformation. The geometry of structures formed within a salt sheet during an early phase of deformation can be concealed by overprinting during later deformation phases, impeding an informed investigation into the early drivers for salt flow. The layered Messinian Evaporites in the deep basins of the Eastern Mediterranean have undergone a Late Messinian phase of deformation, punctuated by truncation of the top of the deformation structures, followed by a Late Pliocene‐Recent phase of deformation. Seismic reflection data show that the Messinian Evaporites are internally dominated by contraction structures that verge basinward in the Late Pliocene‐Recent flow direction, with several apparent detachments. Planform linear trails of fluid escape pipes, documented in the North Levant Basin, that cross‐cut the Messinian Evaporites present natural passive markers for the internal flow kinematics of the salt sheet throughout the Late Pliocene‐Recent phase of deformation. Using the Couette (simple shear) strain profile implied by the fluid escape pipes, we remove the effects of the Late Pliocene‐Recent deformation through cross section and map restorations. The subsequent geometries are far simpler, with upright folds that are now vertically aligned. Once apparently detached structures are demonstrably connected through the Messinian Evaporites. The vergence of the present day intrasalt folds can be taken as an indicator for the Late Pliocene‐Recent flow direction and distinct deformation geometries that connect at various levels through the salt sequence once retro‐deformed can assist when interpreting the salt flow profile. The retro‐deformation is essential for how intra‐Messinian deformation and its drivers are interpreted going forward. Furthermore, simple shear deformation results in erroneous apparent percentage shortening calculations as line length is not conserved, obscuring the strain from the pre‐Pliocene deformational phase. The methodology employed here has important implications for all salt basins that have undergone multiphase deformation.

FUCOM-MOORA and FUCOM-MOOSRA: new MCDM-based knowledge-driven procedures for mineral potential mapping in greenfields

In this study, we present the application of two novel hybrid multiple-criteria decision-making (MCDM) techniques in the mineral potential mapping (MPM), namely FUCOM-MOORA and FUCOM-MOOSRA, as robust computational frameworks for MPM. These were applied to a set of exploration targeting criteria of skarn. The multi-objective optimization method on the basis of ratio analysis (MOORA) and the multi-objective optimization on the basis of simple ratio analysis (MOOSRA) approaches are used to prioritize and rank individual cells. What makes MOORA and MOOSRA more reliable compared to many other methods is the fact that the optimizations procedure is applied to calculate the prospectivity score of individual unit cells. This reduces the uncertainty stemming from erroneous mathematical calculations. The full consistency method (FUCOM), on the other hand, is useful for assigning weights to the spatial proxies. The FUCOM method, as a pairwise comparison method, reduces a large number of pairwise comparisons of similar and popular approaches such as analytic hierarchy process (AHP) with nleft( {n - 1} right)/2 and the best–worst method (BWM) with 2n - 3 number of pairwise comparisons with n - 1 which leads to a less time-consuming and more consistent performance compared with AHP and BWM. These were applied to a set of exploration targeting criteria of skarn iron deposits from Central Iran. Two potential maps were retrieved from the procedures applied, the comparison of which using correct classification rates and field checks revealed the superiority of FUCOM-MOOSRA over the FUCOM-MOORA.

Assessing Lava Flow Subpixel Surface Roughness and Particle Size Distribution for Improved Thermal Inertia Interpretations

Apparent thermal inertia (ATI) is a remote sensing-based thermophysical approximation used to estimate surface properties such as particle size or soil moisture, but is subject to oversimplifications if uniform surface materials are assumed. Geological surfaces realistically contain multiple types of materials that are represented by mixed pixels in a digital image that can dramatically affect the derived thermal response. Thus, the current surface uniformity assumption can lead to erroneous calculations. To define how these mixed particle size surfaces affect ATI, a multi-instrument, multi-spectral study was conducted at the North Coulee rhyolite flow, Mono Domes (California). This flow is compositionally homogenous with particle sizes ranging from silt size to boulders, making it an ideal location to understand the relationship between particle size distributions and ATI. Multispectral data from orbital sensors with increasing spatial resolutions were analyzed in combination with samples, GPS, and photogrammetry data collected in the field. The surface particle size characteristics divided into three broad categories (fine, moderate, and coarse) were mapped based on WorldView-2 visible data and field observations. Broad categories were validated using a 3-dimensional point cloud derived from structure-from-motion (SfM) methods using field photographs. The areal percentage of each category within an ATI pixel was derived to populate a lookup table (LUT) with the corresponding ATI values to quantify the effect of mixed pixels. Lower ATI values are dominated by fine particles (sand and dust) as expected, however, surfaces with the highest values were predominately moderate-sized cobbles. Pixels with a high areal percentage of coarse sizes display an intermediate ATI value, suggesting that either self-shadowing or trapping of fines lowers the ATI value. Alternatively, areas with a majority of moderate particle sizes have less shadowing and efficient vertical sorting of smaller material, as seen in field data, leaving a thermal derived response indicative of the dominating particle size. This study demonstrates how a uniform property assumption can cause erroneous derived thermal modeling, particularly over surfaces with a high percentage of boulders and large particle sizes. Future thermophysical studies of Earth or other planetary surfaces can greatly benefit from a multi-sensor approach combined with a higher spatial resolution visible dataset.

Glacial influence on late Pleistocene 10Be-derived paleo-erosion rates in the north-western Himalaya, India

Terrestrial cosmogenic nuclide concentrations in fluvial deposits allow estimation of paleo-erosion rates and reconstruction of the response of landscapes to climatic perturbations. In partly ice-covered landscapes, however, incorporation of subglacially-derived sediments that were shielded by ice from cosmic can lead to erroneous erosion rate calculations. Here, we combine in situ-produced 10Be-derived erosion rates, based on sand and pebbles from a fluvial fill terrace and the modern riverbed in the upper Yamuna catchment, with numerical ice flow modelling to quantify this bias. New luminescence and surface exposure ages suggest that aggradation of the exposed deposits occurred between 29.9 ± 2.5 ka and 14.8 ± 2.8 ka. During most of the deposition, glaciers probably covered ∼19% of the catchment. 10Be concentrations of terrace sand samples differ from those of pebble samples. We obtained the lowest erosion rates from quartzite pebbles, which stem from low elevations, and the highest erosion rates from crystalline pebbles, which stem from high elevations in the Yamuna catchment. We explain these different erosion rates by differences in the steepness of the source areas, an effect that prevails throughout the entire aggradation period despite significant former ice-cover. Sand samples, which are thought to be derived from all elevation parts of the catchment, however show lower 10Be concentrations during the aggradation compared to present-day. We argue that this difference is due to a substantial subglacial origin of the sand during the aggradation period, and not necessarily related to enhanced erosion. We conclude that aggradation of the valley fill in the Yamuna catchment is most likely due to reduced discharge, and only marginally related to higher erosion rates during the late Pleistocene.

RESEARCH OF MECHANOCHEMICAL CORROSION OF STEELS 20 AND 09G2S

Background During operation, many metal structures are under conditions of joint exposure to aggressive environments (natural and / or technological) and mechanical loads. Moreover, the damage caused by combined action of corrosion and stress is often more significant than by a simple «application» of damage caused by mechanical stress and the influence of an aggressive environment acting separately. Carrying out destructive tensile testing of equipment materials, there is a possibility of inaccurate results on the determination of the mechanical characteristics of this material in connection with the actual operation of the material in an aggressive environment. This, in turn, can lead to erroneous calculations of the tensile strength and resource of the equipment. In this regard, the study of the behavior of materials under the influence of various mechanical loads in aggressive environments, as well as the determination of the limiting state of a metal by measuring its electrode potential, are of particular relevance. Aims and Objectives Determination of the influence of a corrosive medium on the change in the mechanical properties of structural steels 09G2S and 20 using the tensile test as an example. Identification of the dependence of changes in the electrode potential of 09G2S and 20 steels on mechanical loads of various magnitudes. Methods For testing, the most common structural steels used at oil refineries and petrochemical plants - steel 20 and 09G2S - were selected. Tensile tests were carried out in accordance with State Standard 1497-84 «Metals. Tensile test methods». The aggressive environment was selected according to State Standard R 9.905-2007 (ISO 7384: 2001, ISO 11845: 1995) «Unified system of protection against corrosion and aging. Corrosion test methods. General requirements». Tensile tests of the samples were carried out on a tensile testing machine IR 5113-100 in accordance with the Equipment Operation Manual and using a corrosion-proof cell made of organic glass. Aggressive experimental medium was a 3 % aqueous solution of NaCl. Results As a result of tests, it was found that the mechanical properties of low-alloy steel 09G2S and carbon steel 20 deteriorate when exposed to an aggressive environment. So, for steel 20 samples, the tensile strength, on average, decreased by 8.8 %, and the time to rupture - by 4.24 %. For specimens made of 09G2S steel, the decrease in tensile strength in a corrosive medium was 23.1 %, and the time to rupture was reduced by 4.3 %. Measurement of electrode potentials during tensile tests showed that stress state can be predicted from changes in metal potential values.

Effect of feedback loops on the sustainability and resilience of human-ecosystems

There is a great concern about the current growing and indiscriminate human activity over the environment that supports us. Many researchers and strategists have predicted human and natural disasters based on assumptions linked to economic, social and environmental trends. Most of these events have either not happened, the impact was far less than projected or they may have been delayed several years. Such situations might have not been due to erroneous assumptions or calculations, but rather to the ability of ecosystems to recover and adapt following a stressful situation or a disruptive event, so called resilience. The mechanisms of how resilience works generally imply intrinsic complex feedback loops of the systems; such loops absorb the external impacts and distribute them through the different elements that conform the system. This work analyzes a social feedback loop in the dynamics of a human-ecosystem and its consequences in the search for sustainable governmental targets. The loop is derived from the uncertainties in the demographic parameters and is incorporated into a mass-based compartmental model of a human ecosystem with social inequity. The methodology has been applied to three different types of societies with different development levels, using five different governmental targets. As expected, it is clear that feedback loops affect the behavior of the system. Results show that the same government target provides different results for different societies. Societies with a higher level of development present a better economic-social-environmental performance when an environmental target is used, such as GHG emissions; on the other hand, the society with less development presents a better performance when the used target is related to the economics of the system. In order to achieve a sufficiently resilient and sustainable society, the choice of an accurate governmental target is crucial since the objectives act differently for each type of society. Results also show that decision variables have more variation in the first periods of the analysis being practically stable in the final years. Then, the initial years of the simulation analysis are the most important to stabilize the system. Therefore, in real-world societies, not only the choice of the objective is important, but also the feedback mechanisms. Those mechanisms have to be implemented as quickly as possible, in order to identify or avoid probable future catastrophic scenarios.