Academic literature on the topic 'Series Iron Loss'

In a variety of motor models, the effects of iron-loss (ILS) on motor control accuracy and efficiency are generally ignored. This makes it difficult for the motor control system to obtain accurate control parameters (especially on high speed and low load conditions), and limits the improvement of motor control accuracy. This paper aims to clarify the influence of different ILS modeling and observation methods on motor control performance. Three equivalent models of motors with iron losses are compared. These models are: A parallel model, a series model and the simplified traditional model. Three tests are conducted to obtain the effect of ILS perturbation on ILS estimation results, and then to derive the sensitivity of the motor state and torque to the perturbation. These test conditions include: Ideal no-load, heavy-load, locked-rotor, and ILS perturbations during speed regulation. Simulation results show that the impedance and excitation characteristics of the series model and the parallel model are similar, and the traditional model has the best speed regulation smoothness. The ILS estimation errors of the series model is nearly constant and easy to compensate. For accurate ILS observation results, the series model can achieve better control accuracy.

The paper presents and experimentally verifies a testing method of friction pairs between various materials: steel-cast iron, cast iron-cast iron, and cast iron-ferodo. The applied methodology for the evaluation of tribological mating of a friction part allows for determining the time series of friction torque and mechanical power transmitted by a friction pair at slippage. Time series of parameters variability in the investigated friction process after the loss of contact are presented. In addition, relationships are presented that allow for determining the basic friction pair parameters: friction torque, friction coefficient, and mechanical power. This is a basis for determining the tribological load capacity of a friction pair whose measure has been assumed as the maximum value of torsional torque and mechanical power transmitted by the tested specimens.

This paper presents an online efficiency optimization method for the interior permanent magnet synchronous motor (IPMSM) drive system in an electric vehicle (EV). The proposed method considers accurately the total system losses including fundamental copper and iron losses, harmonic copper and iron losses, magnet loss, and inverter losses. Therefore, it has the capability to always guarantee maximum efficiency control. A highly trusted machine model is built using finite element analysis (FEA). This model considers accurately the magnetic saturation, spatial harmonics, and iron loss effect. The overall system efficiency is estimated online based on the accurate determination of system loss, and then the optimum current angle is defined online for the maximum efficiency per ampere (MEPA) control. A series of results is conducted to show the effectiveness and fidelity of proposed method. The results show the superior performance of proposed method over the conventional offline efficiency optimization methods.

<span>This paper presents an online efficiency optimization method for the interior permanent magnet synchronous motor (IPMSM) drive system in an electric vehicle (EV). The proposed method considers accurately the total system losses including fundamental copper and iron losses, harmonic copper and iron losses, magnet loss, and inverter losses. Therefore, it has the capability to always guarantee maximum efficiency control. A highly trusted machine model is built using finite element analysis (FEA). This model considers accurately the magnetic saturation, spatial harmonics, and iron loss effect. The overall system efficiency is estimated online based on the accurate determination of system loss, and then the optimum current angle is defined online for the maximum efficiency per ampere (MEPA) control. A series of results is conducted to show the effectiveness and fidelity of proposed method. The results show the superior performance of proposed method over the conventional offline efficiency optimization methods.</span>

Abstract. A one-dimensional model of the biogeochemistry and speciation of iron is coupled with the General Ocean Turbulence Model (GOTM) and a NPZD-type ecosystem model. The model is able to simulate the temporal patterns and vertical profiles of dissolved iron (dFe) in the upper ocean at the Bermuda Atlantic Time-series Study site reasonably well. Subsurface model profiles strongly depend on the parameter values chosen for the loss processes for iron, colloidal aggregation and scavenging onto particles. Current estimates for these parameters result in depletion of dFe. A high stability constant of iron-binding organic ligands is required to reproduce the observed degree of organic complexation below the mixed layer. A solubility of atmospherically deposited iron higher than 2% lead to dFe concentrations incompatible with observations. Despite neglecting ultraviolet radiation, the model produces diurnal variations and mean vertical profiles of H2O2 and iron species that are in good agreement with observations.

Abstract. A one-dimensional model of the biogeochemistry and speciation of iron is coupled with the General Ocean Turbulence Model (GOTM) and a NPZD-type ecosystem model. The model is able to simulate the temporal patterns and vertical profiles of dissolved iron (dFe) in the upper ocean at the Bermuda Atlantic Time-series Study site reasonably well. Subsurface model profiles strongly depend on the parameter values chosen for the loss processes for iron, colloidal aggregation and scavenging onto particles. Estimates for these parameters based on observations in particle-rich waters result in depletion of dFe. A high stability constant of iron-binding organic ligands is required to reproduce the observed degree of organic complexation below the mixed layer. The scavenging residence time for iron in the model is shortest in spring and summer, because of the larger abundance of particles, and increases with depth towards values on the order of a hundred years. A solubility of atmospherically deposited iron higher than 2% lead to dFe concentrations incompatible with observations. Despite neglecting ultraviolet radiation, the model produces diurnal variations and mean vertical profiles of H2O2 and iron species that are in good agreement with observations.

Purpose The losses incurred in ferromagnetic materials under PWM excitations must be predicted accurately to optimize the design of modern electrical machines. The purpose of this paper is to employ mathematical hysteresis models (i.e. classical Preisach model) to predict iron losses in electrical steels under PWM excitation without compromising the computational complexity of the model. Design/methodology/approach In this paper, a novel approach based on the dynamic inverse Preisach model is proposed to model the iron losses. The PWM magnetic flux density waveform is decomposed into its harmonic component using Fourier series and a weighted Everett function is computed based on these harmonic components. The Preisach model is applied for the given flux waveform and results are validated against the measurements. Findings The paper predicts the total iron loss by computing a weighted Everett function based on the harmonics present in PWM waveform. Moreover, it formulates the possibility of utilizing the classical Preisach model to predict iron losses under PWM excitation. Research limitations/implications The approach is still limited in terms of its application at high frequencies. This work may eventually lead toward the accurate prediction of iron loss under PWM excitation in electromagnetic machine design. Practical implications The paper provides a simple approach applying the Preisach model for the prediction of iron losses under PWM excitation. The proposed approach does not require additional experimental data beyond B-H loops measured under sinusoidal excitation. Originality/value A novel approach is presented to incorporate the frequency dependence into a static inverse Preisach model. The approach extends the ability of the static Preisach model to compute total iron loss under PWM excitation using a weighted Everett function.

Purpose Inductance, torque and iron loss are the key parameters of switched reluctance motors for belt-driven starter generators. This paper aims to present the analysis of a segmented rotor switched reluctance motor (SSRM) with three types of winding connections for hybrid electric vehicle applications by using a two-dimensional finite element method. Design/methodology/approach The rotor of the studied SSRM consists of a series of discrete segments, while the stator is made up of exciting and auxiliary teeth. First, the concept and structures of the different winding connections are introduced. Then, the magnetic flux path of the three types of winding connections for the SSRM is described. Second, the magnetic flux distributions in the three parts, i.e. the stator yoke, the stator tooth and the rotor segment, are described in detail to calculate the iron losses. Third, three SSRMs with the different winding arrangements are analyzed and compared to evaluate the distinct features of the studied SSRM. The analysis and comparison mainly include self-inductances, mutual inductances, phase currents, output torque and iron loss. Findings It is found that the self-inductances of the three types of winding connections are almost equal, and only the SSRM1 has a positive mutual inductance. In addition, the current waveforms of SSRM1 and SSRM2 are regular. However, it is irregular in SSRM3. It is shown that SSRM1 has better characteristics, such as higher output torque, high power density, lower torque ripple and iron loss. Originality/value This paper proposes and analyzes three novel winding connections for the SSRM to provide guidance for enhancing the output torque and reducing the iron loss to achieve high efficiency.

La obra Lengua y cultura persas para principiantes parte del conocimiento del alfabeto persa y de su sistema de escritura por parte del alumno para conducirle hasta el aprendizaje de la lengua persa. La adquisición de vocabulario, así como la enseñanza de la gramática esencial son otras de las bases sobre las que se asienta el libro. Junto con los contenidos teóricos esta obra alterna, además, una serie de ejercicios para que los alumnos vayan constantemente poniendo en práctica lo que se les va enseñando. Por último, los aspectos socioculturales, religiosos, históricos, gastronómicos, literarios y turísticos de Irán se entremezclan también con el aprendizaje de la lengua con el fin de que los alumnos logren adquirir unos conocimientos básicos y generales de la cultura persa.

Judith is Volume 40 in the acclaimed anchor Bible series of new book-by-book translations of the Old and New Testaments and Apocrypha. In the Apocrypha, Judith is the saint who murdered for her people. She offered herself to Holofernes, the Assyrian general sent by Nebuchadnezzar to destroy the Israelites. After she had charmed Holofernes with flattery and drink, Judith chopped of his head while he lay in a drunken stupor, thereby leaving his troops “headless” and in a state of total panic and confusion. Her victory was celebrated in song and brought peace to her land for years to come. In his illuminating new translation and commentary, Carey A. Moore considers the historicity of the story and explores the author’s true intent: Was it to describe actual events or to compose a fictitious story of other purposes? Was his concern more historical or theological? The story of Judith abounds in ironies. There is Judith, the beautiful woman who lived a stark, celibate existence after her husband’s death had left her a wealthy widow. Born into a sexist society with rigidly defined roles, Judith better “played the man” than did any of her male compatriots. There is Holofernes, the Assyrian conqueror, unable to defeat a small Israelite village after dozens of countries had fallen under his sword. Intent on seducing Judith, Holofernes instead lost his head to her. Perhaps the ultimate irony of all is the story of Judith itself: the timeless tale of a deeply religious woman who became revered not for her poverty but for an act of murder. Dr. Moore’s study of the canonicity of Judith brings perspective to the story’s varied acceptance among both Jews and Christians. It also notes the similarity between this work and the equally popular story of Esther; each woman, through different means, served her people through acts of bravery. The photographs and maps illustrating Judith include depictions of the story of Judith by such masters as Machiavelli, Botticelli, Caravaggio, and Donatello.

Judith is Volume 40 in the acclaimed anchor Bible series of new book-by-book translations of the Old and New Testaments and Apocrypha. In the Apocrypha, Judith is the saint who murdered for her people. She offered herself to Holofernes, the Assyrian general sent by Nebuchadnezzar to destroy the Israelites. After she had charmed Holofernes with flattery and drink, Judith chopped of his head while he lay in a drunken stupor, thereby leaving his troops “headless” and in a state of total panic and confusion. Her victory was celebrated in song and brought peace to her land for years to come. In his illuminating new translation and commentary, Carey A. Moore considers the historicity of the story and explores the author’s true intent: Was it to describe actual events or to compose a fictitious story of other purposes? Was his concern more historical or theological? The story of Judith abounds in ironies. There is Judith, the beautiful woman who lived a stark, celibate existence after her husband’s death had left her a wealthy widow. Born into a sexist society with rigidly defined roles, Judith better “played the man” than did any of her male compatriots. There is Holofernes, the Assyrian conqueror, unable to defeat a small Israelite village after dozens of countries had fallen under his sword. Intent on seducing Judith, Holofernes instead lost his head to her. Perhaps the ultimate irony of all is the story of Judith itself: the timeless tale of a deeply religious woman who became revered not for her poverty but for an act of murder. Dr. Moore’s study of the canonicity of Judith brings perspective to the story’s varied acceptance among both Jews and Christians. It also notes the similarity between this work and the equally popular story of Esther; each woman, through different means, served her people through acts of bravery. The photographs and maps illustrating Judith include depictions of the story of Judith by such masters as Machiavelli, Botticelli, Caravaggio, and Donatello.

AbstractSmall bowel imaging presents a challenge from the variety of clinical presentations and types of disease affecting a long organ. Emergency presentation most often involves suspicion of bowel obstruction, unexplained acute abdominal pain with or without signs of sepsis and overt obscure GI bleeding. Conversely non-emergency referrals relate to non-specific constitutional symptoms including weight loss, abdominal patient, and altered bowel habit suggesting malignancy or inflammatory bowel disease, while iron deficiency anaemia after negative colonoscopy and endoscopy indicates occult obscure GI bleeding. CT is the commonest and best-established method of evaluation, except in the setting of known inflammatory bowel disease where MRI or ultrasound are advantageous because they avoid radiation.The CT protocol must be tailored to the clinical situation. Oral preparation is avoided for acute imaging, with the main focus around prompt contrast enhanced scanning: acute obscure bleeding should include non-contrast, arterial and portal venous phases, while obstruction and acute abdominal pain needs portal venous phase assessment. Pre-contrast imaging allows assessment of intramural haemorrhage where there is prior clinical concern for intestinal ischaemia. Conversely non-urgent assessment allows oral luminal preparation with a neutral contrast such as polyethylene glycol or mannitol and enteric or portal venous phase contrast assessment depending on the indication.

Abstract This volume contributes to research on migration from Latvia, a country in Central Eastern Europe (CEE), following the fall of the Iron Curtain in 1991. The experience of independent Latvia with borders opening up to the world and more specifically to the West has turned out to be both a rewarding and wounding experience for communities in the country. On the rewarding side, individuals have gained liberty – an ability to travel the world freely, to see and live in the countries which were beyond the closed doors of the Soviet Union just some decades ago. This freedom, however, has also brought the sense of cost to the society – people are going abroad as if dissolving into other worlds, away from their small homeland. The context of decreasing birth rates and ageing in the country seems to amplify a feeling of loss which is supported by hard evidence. Research shows a worrying 17% decline in Latvia’s population between 2000 and 2013. One third of this is due to declining birth rates and two-thirds is caused by emigration (Hazans 2016). This situation has turned out to be hurtful experience for communities in Latvia causing a heightened sense of grief especially during the Great Recession which shook the country at the end of the first decade of the twenty-first century. By 2013 the feeling of crises even larger than the economic downturn came to a head in Latvian society, pushing the government for the first time in the history of independent Latvia to recognise the migration of the country’s nationals and to acknowledge diaspora politics as an important item on the national policy agenda.

AbstractA teenage girl’s journey of leaving her home in Iran to move to Canada with her family is shaped around a secret box of memories that needs to accompany the main character to her new home in Canada. The story focuses on themes of belonging, “home”, identity; and experiences of Iranian teenage women told through a simple tale of teenagehood in Iran. The teenage girl experiences an identity crisis that starts with the migration journey itself and as the family arrives in the Canadian airport for the very first time, new insights into their immigrant realities unfold.The story is called Things Lost, Things Not Lost, And the Ones That Were Found on The Way. It is a simple story of a family’s journey to Canada, and it begins when the family is leaving Tehran, ending when they arrive at Toronto’s Pearson International airport. Told in the voice of the family’s teenage daughter, it is a mix of imagination and experiences I personally have lived through. What I have tried to capture in this playful snapshot of a family’s journey are the feelings and emotions they experience before immigrating to a new country. These feelings of letting go are intertwined with meaningful pieces of identity and the journey is full of contradictions that mimic the paradoxes and the challenges immigrant families experience as they try to adapt to their new life, including changes in family dynamics and gender relations.

AbstractThis paper examines how self-designation among Afghan refugees and migrants is evolving. While terms such as muhājir, “refugee,” with a religious connotation, panāhenda, “refugee,” and mosāfer, “traveller,” were used by Afghans in the 1980s and 1990s, they no longer have the favour of younger people who might have grown up in Iran or Pakistan and often aspire to try their chance in the West. New generations tend to describe their situation with words such as āwāra, sargardān, dar-ba-dar, which generally convey the idea of “wandering,” “vagrancy,” “homelessness,” “lack of purpose.” This evolving terminology suggest that exile has lost the religious and political significance it might have had during the anti-Soviet jihad, on the one hand. It also can be interpreted as a quest for meaning in life, an assertion of agency in an effort to define their place in this world, on the other hand. Social media and blogs run by Afghans evoke an ontology of displacement and mobility, which ultimately elicits a form of cosmopolitanism from bellow and resonates with the social, political and economic unpredictability in Afghanistan.

The way in which Ono no Komachi’s personal collection (Komachishū) loosely shapes her “life” is believed to have been influenced not only by stories and legends that were orally transmitted soon after her death, but also by the image of flowering and decline depicted in her most celebrated poem, Hana no iro wa. Through an analysis of the textual lines of the collection, this paper aims to shed light on the significance of another renowned poem by Komachi, Wabinureba. This poem is pivotal in establishing one of the central themes of the Komachishū - Komachi’s later life of misery (ukimi) - and serves as inspiration for the chōka that narrates Komachi’s sad and uncertain existence following the loss of her partner. By examining the chōka, this contribution further argues that, as it was included in a previous 45-poem variant text of the Komachishū, it could have served as a potential framework for portraying Komachi's life as depicted in the expanded popular text (the 116-poem rufubon) of the collection.

Anaemia is a very common problem in low- and middle-income countries (LMICs): 27% of the world’s population or 1.93 billion people are affected by anaemia (2013) and more than 90% of people with anaemia live in the developing world. Preschool children and women of reproductive age are particularly affected by anaemia and more 60% of anaemia is caused by iron deficiency. Causes of anaemia in LMICs—this is often multifactorial, with causes including (1) nutritional deficiencies—iron, folate, vitamin B₁₂; (2) chronic infection—including malaria, tuberculosis, AIDS; (3) blood loss—hookworm, schistosomiasis; (4) protein–energy malnutrition; (5) malabsorption—for example, tropical sprue; (6) hereditary—for example, thalassaemias, haemoglobin variants, glucose-6-phosphate dehydrogenase deficiency. A series of vicious cycles exist in LMICs—maternal anaemia due to iron or folate deficiency and chronic malaria is associated with the birth of underweight infants who frequently have low iron stores, may also be folate deplete, and are usually anaemic from about 6 months of age. Such infants are prone to infection, particularly gastrointestinal, and may be further depleted of iron or folate by inappropriately prolonged breastfeeding or weaning onto an inadequate diet. They are exposed to hookworm infection as soon as they start to crawl, malaria becomes an important problem after 6 months, and in many populations the increasingly common haemoglobinopathies are a further cause of anaemia after the first few months of life.

Ship shaking can cause cargo PWP (pore water pressure) increasing, the prediction of PWP is helpful for navigation safety. This paper presents a machine learning method for PWP time series prediction learning. Source data of iron concentrate are collected from scaled model test, they are used to train a time series prediction model and test the accuracy and effective of our method. The proposed method is based on PSR (phase space reconstruction) and LSTM (Long Short-Term Memory) Network. A input matrix is constructed by phase space reconstruction technology and the prediction model can be learned by a specific Long Short-Term Memory Network. The single-step pore water pressure prediction model is achieved, when MSE loss function value is minimum, the R value 0.98 is maximum is better than the baseline R value 0.93. This result suggests that this PSR-LSTM is more effective than LSTM, it can be a complement for physical test and numerical simulation.

This chapter first surveys the diverse methods for melting and shaping iron. I then consider a series of case studies in which archaeological research has contributed to understanding the strategic choices of ironmasters as they confronted myriad contingencies and opportunities. Archaeologists explored early smelting activities in pueblos in New Mexico in the 1600s. Those activities were dwarfed by enterprises launched in British North America in the 1700s. Large-scale investments on the Saugus River in Massachusetts and in Trenton, New Jersey, were followed by more circumspect investments in Delaware, Maryland, and Pennsylvania. An early form of vertically integrated enterprise in an iron plantation in South Carolina, was exceeded by far-flung, interdependent networks of production at the Tredegar works of Virginia. The remarkable resilience of women in managing family-run iron plants played out in Ohio and Pennsylvania. Notable technological innovations were undertaken at iron manufacturers in Tennessee and New York. Class dynamics shaped the residential landscape of managers and workers in Michigan. Finally, a quest for accelerated water power to propel iron foundries in West Virginia cost little in capital and a staggering price in lives lost.

This final chapter analyzes the chemical logic in the tetrapyrrole biosynthetic pathway to heme B with focus on how the aminomethylpyrrole heterocycle of prophobilinogen is assembled and then utilized to build the tetrapyrrole macrocycles of heme and chlorphyll. Enzymatic steps include the formation of the porphobilinogen building block by aldol condensative dimerization of 4-aminolevulinate, its chain extension to the linear tetrapyrrole hydroxybilane, and its enzyme-directed cyclization to uroporphyrinogen III. Subsequently the tailoring of the macrocycle periphery involves loss of the six of the eight peripheral carboxylates as CO2, six-electron oxidation of the macrocycle to a 20 π-electron system and ferrous iron insertion to give heme B. The aminopyrrole framework of porphobilinogen serves both as electrophile via a C2 azafulvene form and as a nucleophile at C5. Fourteen of the starting 48.

This volume introduction analyzes a pervasive fantasy in American popular media: the desire to escape an “iron age” deemed materially and morally degraded in comparison with an idealized lost world that people hope somehow to recover. This idealized “golden age” is viewed with the painful longing of nostalgia and the sorrow of belatedness from the degraded “iron age” of the viewer’s present time, often accompanied by inquiry into how and why golden conditions no longer obtain. Self-proclaimed heirs to classical antiquity’s cultural patrimony adopted this myth with alacrity, and its deployment can be traced continuously throughout the classical tradition, including in popular media not conventionally associated with classicism. The introduction reviews key strands of golden-age discourse in ancient Greek and Roman texts, including views on human-divine relations, gender relations, and technological innovations; and modern receptions of historical societies as golden ages to be emulated, especially Periclean Athens, Thermopylae-era Sparta, and Augustan Rome. Case studies include the Vergilian concept of “Arcadia” as deployed in the sci-fi television series The 100 and “golden age thinking” as a psychological malady in Woody Allen’s Midnight in Paris.

Abstract The cyclic oxidation behavior of four commercial iron-base 800 series chromia-forming alloys was studied at 1000 °C in still air. Each thermal cycle consisted of one day at temperature followed by air-cooling to room temperature. Two different types of alloys were studied (800 and 800HT), with the alloys being supplied by two different producers. Although the alloys were of similar chemical composition, their variations in microstructure and minor constituent contents were apparently sufficiently different to cause marked differences in oxidation behavior. The 800HT alloys generally performed the worst, undergoing rapid weight-loss kinetics after a period of relatively protective oxidation. The time required for the commencement of rapid weight-loss kinetics depended significantly on the producer of the 800HT alloy. The oxidation behavior of the 800 alloys was also producer dependent, but not to the significant extent found for the 800HT alloys.

Abstract The corrosive effects of iron monosulfide particles deposited on carbon steel surfaces were investigated in a series of autoclave experiments. The H2S and CO2 partial pressures were varied in the range of 1-20 bar. Experiments were run at temperatures in the range of 10-120 °C. The test solutions consisted of high-salinity brine (100 g/L NaCl, 0.0025 m bicarbonate) and low-salinity condensed water (0.1 g/L NaCl). The duration of the tests was typically 14 days. Both weight loss corrosion and localized corrosion data were obtained. The entire surfaces of the exposed coupons were scanned with a 3D profilometer, obtaining detailed data on localized corrosion morphology, pit frequency and pit depths. The presence of FeS deposits was found to significantly increase both weight loss and local penetration rates in experiments with high H2S/CO2 partial pressures (20-25 bar total). The results are discussed on the background of available literature.

Abstract The nature of the iron sulfide films formed on steel surfaces during H2S/CO2 corrosion is a key parameter for pH stabilisation in sour gas pipelines, and will also affect the efficiency of corrosion inhibitors. On this background, a series of systematic experimental studies of iron sulfide corrosion film growth in aqueous H2S/CO2 environments have been initiated. This contribution presents results obtained in the initial stages of these studies using gravimetric (mass loss) methods, FE-SEM and EDS. X65 carbon steel samples were exposed to sour conditions for various periods of time up to 10 days. Evidence of iron sulfide layer formation governed by the parabolic film growth rate law was found for the test conditions reported, indicating that the corrosion and film growth rates in these cases were limited by the electronic conductivity of the film or mass transport, probably Fe2+ diffusion, across the corrosion film. Assessment of the films by SEM revealed that the morphology changes with exposure time within the range studied.

Abstract Understanding and controlling hydrogen sulfide (H2S) corrosion becomes increasingly important in the petroleum industry. Iron sulfide is formed on the internal pipeline surface as a corrosion product of carbon steel in an environment containing H2S. Some of the iron sulfide particles are suspended in the liquid phase or deposited at the bottom of a pipeline. Iron sulfide decreases the corrosion inhibition efficiency due to the adsorption of corrosion inhibitor on the surface of iron sulfide particles. The objectives of this study are to investigate the effect of iron sulfide on the efficiency of a corrosion inhibitor in a highly sour environment and to explore effective technical methodologies to study H2S corrosion and inhibition. Experiments were performed in a series of autoclaves with a total pressure of 896 kPa (538 kPa CO2, 290 kPa H2S, and 69 kPa water vapor). Iron sulfide effects were studied separately in two different cases: directly deposited on the steel surface or suspended in the test solution. In the experiments, weight loss was applied to study the corrosion inhibition efficiency. Corrosion product films/scales formed on the surface of the steel were analyzed by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDX).

Abstract The effect of CaCO3 saturation on sour corrosion was tested in a series of autoclave experiments. The main objective was to investigate a proposed mechanism where an inner layer of CaCO3 would form and reduce the protectiveness of iron sulfide layers. CaCO3 saturation ratios in the range of 0-4 were studied with two different gas compositions; 2.5 bar H2S + 2.5 bar CO2, and 0.05 bar H2S + 5 bar CO2. The temperature was 90°C and the salinity 100 g/L in all experiments. Weight loss corrsion rates were obtained, and the corrosion surfaces and corrosion products were analyzed with 3D profilometry and SEM/EDS. The presence of continuous calcic layers could not be observed in this study, but it was nevertheless found that the corrosion rates in solutions with dissolved calcium can be significantly higher than in calcium-free solution. The findings are relevant for the oil&gas industry as production rates of formation water typically will increase during mid/late life production, and several new field will produce formation water shortly after start-up.

Abstract Oilfield brine contains magnesium (Mg2+) and calcium (Ca2+) ions. Although carbon dioxide (CO2) corrosion of mild steel and its corrosion products has been extensively studied, the effect of Mg2+ and Ca2+ are frequently overlooked by researchers. Usually, a simple test electrolyte with various percentages of dissolved sodium chloride (NaCl) has been employed to study the mechanism of CO2 corrosion to avoiding complications relating to the water chemistry. The current paper is a continuation of a series of publications aimed at investigating the effect of water chemistries associated with Mg2+ and Ca2+ on the CO2 corrosion mechanism. A combination of electrochemical methods, weight loss technique, and surface characterization tools were employed over the course of long-term experiments with a controlled water chemistry and well-defined mass transfer conditions. The presence of Ca2+ in the electrolyte and the formation of a uniform calcium carbonate (CaCO3) layer on the steel surface facilitated precipitation of a protective iron carbonate (FeCO3) adjacent to the substrate. Localized corrosion was observed in the presence of high concentration of Mg2+ but was not detected in the simultaneous presence of Ca2+ and Mg2+ with a typical concentration ratio observed in oilfields (Ca2+/Mg2+=7).

Abstract The use of high strength American Petroleum Institute (API)(1) 5CT Q-125 Type 1 Cr-Mo steel tubing is planned for treated seawater injection wells for several deepwater projects. The API 5CT Q-125 Type 1 Cr-Mo steel tubing offers multimillion dollar savings per well, compared to the widely used Super Duplex 25 Cr (Unified Numbering system [UNS](2) S32760) tubing. Holding oxygen levels at an average of 10 ppb, with alarm and shut-in levels of 40 ppb, will maintain corrosion rates at an acceptable level for the life of the field. Several field case histories will be presented from operations in deepwater West Africa, where seawater floods have been in service for 7 to 9 years (or more) without failure. Corrosion rate calculations of the expected wall loss of the Cr-Mo steel tubing and connection were also made to ensure that sufficient mechanical properties remain intact for the life of the projects. The results of the 40-pin field caliper surveys from deepwater West Africa water injection wells will be presented. Carbon steel piping from a subsea water injection jumper retrieved from the field showed minimal corrosion after over 8 years and over 53 million bbls of injected seawater. The seawater treating process design consists of a series of course and fine filters, a 40-μ security filter, followed by the sulfate removal unit (SRU) membranes. A gas-stripping tower removes oxygen down to 40 ppb. Chemical treatment follows, removing oxygen to less than 10 ppb. The sulfate removal membrane is a nanofiltration system that rejects bacteria along with some chlorides and removes sulfate to less than 40 ppm. Multiple oxygen sensors prevent unplanned excursions and there is no bypass piping around the stripping tower or sulfate membrane equipment. Low levels of oxygen in solution are not thermodynamically favored in the presence of dissolved iron. Ionic equilibrium software was used to predict the equilibrium oxygen concentration as a function of dissolved iron in the seawater.

Abstract Laboratory examination of one of the first core debris samples removed from the Three Mile Island Unit 2 (TMI-2) reactor was performed as part of a series of in-depth evaluations of postaccident core damage. Sample analysis has given new information on the quenched high- temperature reaction products formed during the TMI-2 loss-of-coolant accident. The rapid exothermic steam corrosion of Zircaloy and stainless steel cladding and localized uranium dioxideZircaloy reactions are considered the main processes. The sample was removed from a depth of three inches below the top surface of the rubble bed along the axial centerline of the reactor. The debris was composed primarily of granular ceramic fragments, resolidified metallic and "lava rock-like" materials. About one-fourth of the particles contained up to 20% open porosity and appeared to be high temperature reaction products from portions of two or more core components. Uranium dioxide fuel pellet fragments, oxidized cladding, or combinations with reaction product material were also identified. The sample contained free-flowing particles ranging from 1 cm to less than 45 micrometers, with an average size of 2 mm. Debris material was mainly composed of uranium, zirconium, and iron. Nickel, chromium, silver, tin, aluminum, and indium were also present in smaller amounts. All of these elements were present in the original core materials. The observed results are discussed with respect to published analytical predictions.

Abstract High chromium white cast irons are used in a number of applications in alumina refineries where wear is a significant issue. However, recent case studies of failures of white irons in high temperature digestion have suggested that significant corrosion of these materials is occurring and this may be leading to accelerated wear rates. In this paper, the corrosion behavior of a series of high chromium (Cr) white irons in concentrated caustic solutions is studied in the laboratory at temperatures from up to 280°C. The morphology of the oxide films is studied along with corrosion rates measured using weight loss measurements, and this is correlated with compositional and microstructural variations in the white irons. The failure mechanisms of these white irons involve preferential corrosion of the matrix, particularly in circumstances where the matrix is pearlitic. Recommendations regarding the heat treatment and compositions of white irons for use in high temperature digestion are made.

Abstract The Admiral is moored in the Mississippi River at the St. Louis Arch. The river has logs, branches and other debris which travel downstream at about 12 mph (19 kph). An anode system had to be designed to withstand the impact of this debris. A series of high silicon iron button anodes was designed, with the anodes being fastened with through-hull fittings. This required a water tight stuffing, box arrangement within the hull for each anode since the work had to be done while the ship was in the water. Special attention was also paid to electronic interference with the sophisticated computer equipment on board; this included precautions in the rectifier circuitry and the use of automatic potential control to keep the hull at a constant potential.

En el ecosistema de innovación y emprendimiento de alto impacto en América Latina y el Caribe (ALC) vemos cómo emprendedores/as cuentan experiencias difíciles de su día a día para mantener o hacer crecer exitosamente sus emprendimientos. Estas presiones diarias suelen estar vinculadas a factores que comúnmente podemos ver y medir, como el factor financiero, el factor operativo y los factores de sostenibilidad o escalabilidad. Pero se puede ver y conocer poco sobre el impacto y las posibles consecuencias de estas presiones en la vida personal, familiar o cotidiana de los seres humanos detrás de los emprendimientos. Un factor invisible que es hora de visibilizar. Si queremos fortalecer el ecosistema emprendedor de la región e impulsar su gran capacidad innovadora, es necesario atender un factor invisible pero fundamental: el bienestar y la salud mental de emprendedores/as de alto impacto. Los emprendimientos de alto impacto son una parte esencial de las economías dinámicas de nuestros países. Sin embargo, en muchos casos, estos/as emprendedores/as enfrentan circunstancias y desafíos muy particulares de la región. A las presiones financieras y operativas cotidianas se suman contextos políticos, económicos y sociales muy cambiantes, así como recientemente los duros impactos por la pandemia del COVID-19. Esto ha generado un ambiente de alta tensión e incertidumbre en los emprendedores/as para poder mantener o hacer crecer sus iniciativas sin descuidar el compromiso laboral con sus equipos. El hecho que este desafío personal muchas veces parezca invisible y se suela enfrentar en solitario, por estigmas o prejuicios, hace que el sector de EAI sea “mucho más propenso a sufrir dolencias en bienestar y salud mental, como estados de ansiedad, fatiga, depresión o agotamiento generalizado (síndrome de burnout), en comparación con la población en general” (Endeavor, 2020). Con el objetivo de entender y visibilizar la situación del bienestar y la salud mental, específicamente en el ecosistema emprendedor de Alto Impacto en la región, esta investigación realizó un estudio de carácter exploratorio para identificar y entrevistar a un grupo diverso de emprendedores/as en varios países de ALC. Fundadores/as o colaboradores, de diverso género, en varios tipos de industrias, con emprendimientos en distintas etapas y con diverso alcance geográfico o de mercado aceptaron participar voluntariamente para compartir sus experiencias y opiniones. Desde esta exploración, que se enfoca puntualmente en analizar la situación actual de las personas participantes, creemos que es posible reflejar lo que potencialmente afecta a una mayor parte del ecosistema. Esto puede ayudar a visibilizar la importancia de atenderlo para quienes están detrás de los emprendimientos, pero también para quienes los incuban, los aceleran o invierten en ellos. Ayudar a potenciar buenas prácticas, financiar investigación y ofrecer programas o herramientas de acompañamiento especializado al ecosistema emprendedor de la región es fundamental. Entendiendo el momento que vive la región y buscando fortalecer el crecimiento del ecosistema, se debe impulsar estratégicamente un nuevo enfoque: si los/ as emprendedores/as están bien, los emprendimientos irán mejor.

Introducción En 2023 el Banco de la República celebra 100 años de su fundación. Este es un aniversario de gran significado, el cual ofrece la oportunidad de resaltar el aporte que el Banco ha hecho al desarrollo del país. Su trayectoria como garante de la estabilidad monetaria lo ha consolidado como la institución estatal independiente que genera mayor confianza entre los colombianos por su transparencia, capacidad de gestión y el cumplimiento efectivo de las funciones de banca central y culturales encomendadas en la Constitución y la Ley. En una fecha tan importante como esta, la Junta Directiva del Banco de la República (JDBR) hace un reconocimiento a las generaciones de directivos y funcionarios que con su compromiso y dedicación contribuyeron a engrandecer esta institución1. El mandato del Banco de la República se consolidó en la Asamblea Nacional Constituyente de 1991, para cuya integración los ciudadanos tuvieron la oportunidad de elegir a las setenta personas que tendrían como tarea redactar una nueva constitución. Los dirigentes de los tres movimientos políticos más votados fueron elegidos presidentes de la Asamblea, y esta presidencia tripartita reflejó la pluralidad y la necesidad de consenso entre las diferentes fuerzas políticas para sacar adelante la reforma. Entre los asuntos considerados, la Asamblea Nacional Constituyente le otorgó especial importancia a la estabilidad monetaria. Por esta razón decidió incluir el tema de banca central y dotar al Banco de la República de la autonomía necesaria para utilizar los instrumentos a su cargo sin injerencia de otras autoridades. El constituyente entendió que velar por la estabilidad de precios es un deber del Estado y que la entidad responsable de este cometido debe estar consagrada en la Constitución y contar con la capacidad técnica y autonomía institucional necesaria para adoptar las decisiones que considere pertinentes para alcanzar este objetivo fundamental, en coordinación con la política económica general. En particular, el artículo 373 estableció que “el Estado, por intermedio del Banco de la República, velará por el mantenimiento de la capacidad adquisitiva de la moneda”, disposición que coincidía con el esquema de banca central adoptado por países exitosos en el control de la inflación. En 1999, mediante sentencia 481, la Corte Constitucional indicó que “el deber de mantener la capacidad adquisitiva de la moneda no solo se predica de la autoridad monetaria, crediticia y cambiaria, esto es de la Junta del Banco de la República, sino también de quienes tienen responsabilidades en la formulación y ejecución de la política económica general del país” y que “la finalidad constitucional básica del Banco de la República es la protección de la moneda sana, pero esa autoridad debe tomar en consideración en sus decisiones los otros objetivos económicos de la intervención del Estado, como el pleno empleo, pues sus funciones deben coordinarse con la política económica general.” La reforma al Banco de la República concertada en la Constituyente de 1991 y en la Ley 31 de 1992 se puede resumir en los siguientes aspectos: i) asignó al Banco un mandato específico: mantener la capacidad adquisitiva de la moneda, en coordinación con la política económica general; ii) designó a la JDBR como autoridad monetaria, cambiaria y crediticia; iii) otorgó al Banco y a su Junta Directiva un importante grado de independencia frente al Gobierno; iv) prohibió al Banco otorgar crédito al sector privado distinto del financiero; v) estableció que para otorgar crédito al Gobierno se requería del voto unánime de su Junta Directiva, a menos que se trate de operaciones de mercado abierto; vi) determinó que el legislador, en ningún caso, podrá ordenar cupos de crédito a favor del Estado o de los particulares; vii) designó al Congreso, en representación de la sociedad, como principal destinatario del ejercicio de rendición de informes del Banco; y viii) delegó en el presidente de la República la función de inspección, vigilancia y control sobre el Banco de la República. Los miembros de la Asamblea Nacional Constituyente entendieron claramente que los beneficios de una inflación baja y estable se extienden a toda la sociedad y contribuyen al buen funcionamiento del sistema económico. Entre los más importantes cabe mencionar que una inflación baja promueve el uso eficiente de los recursos productivos, al permitir que los precios relativos guíen de mejor forma la asignación de recursos, lo cual promueve el crecimiento económico y aumenta el bienestar de la población. Igualmente, una inflación baja reduce la incertidumbre sobre la rentabilidad esperada de la inversión y sobre el precio futuro de los activos, lo que aumenta la confianza de los agentes económicos, facilita la financiación de largo plazo y estimula la inversión. Una inflación baja evita redistribuciones arbitrarias del ingreso y la riqueza, debido a que los estratos de ingresos bajos de la población no pueden protegerse de la inflación mediante la diversificación de sus activos, y concentran una elevada proporción de su ingreso en la compra de alimentos y otros bienes básicos, ítems que generalmente son los más afectados por los choques inflacionarios2. Por otra parte, una baja inflación facilita las negociaciones salariales, lo cual crea un buen clima laboral y reduce la volatilidad del nivel de empleo. Finalmente, una inflación baja contribuye a que el sistema de impuestos sea más transparente y equitativo, al evitar las distorsiones que la inflación introduce sobre el valor de los activos y de los ingresos que componen la base tributaria. Desde el punto de vista de la autoridad monetaria, uno de los beneficios más relevantes de una inflación baja es la credibilidad que los agentes económicos adquieren en la meta de inflación, lo que la convierte en un ancla nominal efectiva sobre el nivel de precios. Al recibir su mandato, y en uso de su autonomía, el Banco de la República empezó a anunciar metas puntuales de inflación anual a partir de 1992. Si bien en esta primera etapa las metas de inflación propuestas no se lograron cumplir de forma precisa, sí se consiguió imprimirle a la inflación una tendencia descendente, que la llevó desde un nivel del 32,4% en 1990 al 16,7% en 1998. Para aquella época la tasa de cambio se mantenía dentro de una banda, lo cual limitaba la efectividad de la política monetaria, que buscaba cumplir simultáneamente una meta de inflación y un objetivo de tasa de cambio. La crisis asiática se contagió a las economías emergentes y afectó de manera importante a la economía colombiana. La tasa de cambio presentó una fuerte presión a la depreciación al cerrarse el acceso al financiamiento externo en condiciones de un elevado desequilibrio externo. Lo anterior, junto con la falta de flexibilidad cambiaria, impidió hacer una política monetaria contracíclica, lo que condujo a una contracción del PIB del 4,2% en dicho año. En este contexto de desaceleración económica, la inflación anual se redujo al 9,2% a finales de 1999, situándose por debajo de la meta del 15% que se había fijado para ese año. Este episodio reveló plenamente lo costoso que podría ser, en términos de actividad económica, el tener simultáneamente metas para la inflación y para la tasa de cambio. Hacia finales de 1999 el Banco de la República anunció la adopción de un nuevo régimen de política monetaria que denominó Esquema de Inflación Objetivo. Este régimen, conocido internacionalmente como ‘Inflation Targeting,’ venía ganando creciente aceptación en países desarrollados, al haber sido adoptado a partir de 1991 por Nueva Zelanda, Canadá e Inglaterra, entre otros, logrando importantes avances en el manejo de la inflación, sin incurrir en costos en términos de actividad económica. En América Latina, Brasil y Chile también lo acogieron en 1999. En el caso colombiano, el último requisito pendiente por cumplir para adoptar dicho esquema de política era la flexibilidad de la tasa de cambio, la cual se materializó hacia septiembre de 1999, cuando la JDBR decidió abandonar las bandas cambiarias para permitir que la tasa de cambio se determinara libremente en el mercado. De forma coherente con el mandato constitucional, el objetivo fundamental de este nuevo esquema de política consistía en “el cumplimiento de una meta de inflación que contribuya a mantener un crecimiento del producto alrededor de su capacidad potencial”3. Dicha capacidad potencial se entendía como aquel crecimiento del PIB que la economía puede obtener si utiliza plenamente sus recursos productivos. Para cumplir este objetivo la política monetaria debe cumplir necesariamente un papel contracíclico en la economía. Ello porque cuando la actividad económica está por debajo de su potencial y existen recursos ociosos, la autoridad monetaria puede reducir la tasa de interés ante la ausencia de presiones inflacionarias para estimular por esa vía la economía y, de manera inversa, cuando el producto supera su capacidad potencial. Este principio de política, que está inmerso en los modelos para guiar la postura de política monetaria, hace que, en el mediano plazo, sean totalmente compatibles los objetivos del cumplimiento de la meta de inflación y de un nivel de actividad económica compatible con su capacidad productiva. Para alcanzar este propósito, en el esquema de inflación objetivo se utiliza la tasa de interés del mercado monetario (a la cual el banco central suministra liquidez primaria a los bancos comerciales), como el instrumento primordial de política. Con ello se sustituyó la cantidad de dinero como meta intermedia de política monetaria, que el Banco de la República, al igual que varios otros bancos centrales, utilizaron por mucho tiempo. En el caso colombiano, el objetivo del nuevo esquema de política monetaria implicaba, en términos prácticos, que la recuperación de la economía, luego de la contracción ocurrida en 1999, debía lograrse al tiempo que se cumplían las metas decrecientes de inflación establecidas por la JDBR. De manera notable este propósito se cumplió. En la primera mitad de la década del 2000 la actividad económica logró una recuperación importante, hasta alcanzar un crecimiento del 6,8% en 2006. Entretanto, la inflación fue descendiendo gradualmente, en línea con las metas de inflación. Fue así como la tasa de inflación se redujo desde el 9,2% en 1999 al 4,5% en 2006, cumpliendo con la meta de inflación establecida para ese año, mientras que el PIB alcanzó su nivel potencial. Después de lograrse este equilibrio en 2006, la inflación repuntó al 5,7% en 2007, por encima de la meta del 4% fijada para ese año, debido a que el crecimiento del PIB del 7,5% superó su capacidad potencial4. Luego de comprobarse la eficacia del esquema de inflación objetivo en sus primeros años de operación, este régimen de política continuó consolidándose a medida que la JDBR y el equipo técnico ganaron experiencia en su manejo y se incorporaron modelos económicos de última tecnología para diagnosticar el estado presente y futuro de la economía, y evaluar la persistencia de los desvíos de la inflación y sus expectativas con respecto a la meta de inflación. A partir de 2010 la JDBR estableció la meta de inflación anual de largo plazo del 3%, que continúa vigente en la actualidad. La menor inflación ha contribuido a crear un entorno macroeconómico más estable, que ha favorecido el crecimiento económico sostenido, la estabilidad financiera, el desarrollo del mercado de capitales y el funcionamiento de los sistemas de pagos. Gracias a ello se lograron reducciones en la prima por riesgo inflacionario y menores tasas de interés de los TES y de crédito. A su vez, la duración de la deuda interna pública aumentó de forma importante pasando de 2,27 años en diciembre de 2002 a 5,86 años en diciembre de 2022 y la profundización financiera, medida como el nivel de la cartera como porcentaje del PIB, pasó de cerca del 20% a mediados de la década de los noventa a valores superiores al 45% en años recientes, en un contexto saludable de los establecimientos de crédito. Los logros tangibles alcanzados por el Banco de la República en el manejo de la inflación al haber contado con la autonomía que le otorgó la Constitución para cumplir con el mandato de preservar el poder adquisitivo de la moneda, junto con los importantes beneficios que se derivaron del proceso de llevar la inflación a su meta de largo plazo, hacen que el reto que actualmente enfrenta la JDBR de retornar la inflación a la meta del 3% sea aún más exigente y apremiante. Como es bien conocido, a partir de 2021, y especialmente en 2022, la inflación en Colombia volvió a convertirse en un serio problema económico, con elevados costos de bienestar. El fenómeno inflacionario no ha sido exclusivo de Colombia y es así como muchos otros países desarrollados y emergentes han visto alejarse sus tasas de inflación de las metas propuestas por sus bancos centrales5. Las razones de este fenómeno se han analizado en los recientes Informes al Congreso, y en esta nueva entrega se profundiza al respecto con información actualizada. La sólida base institucional y técnica que soporta el esquema de inflación objetivo bajo el cual opera la estrategia de política monetaria le da a la JDBR los elementos necesarios para enfrentar con confianza este difícil reto. Al respecto, en su comunicado del 25 de noviembre la JDBR reiteró su compromiso con la meta de inflación del 3,0%, la cual prevé alcanzar hacia finales de 20246. La política monetaria continuará enfocada en cumplir este objetivo, al tiempo que velará por la sostenibilidad de la actividad económica, tal y como lo ordena la Constitución. Las encuestas a analistas llevadas a cabo en marzo mostraron un incremento importante (del 32,3% en enero al 48,5% en marzo) en el porcentaje de respuestas que sitúan las expectativas de inflación a dos años o más en un rango entre el 3% y 4%. Este es un indicativo claro de recuperación de credibilidad en la meta de inflación a mediano plazo, lo cual guarda coherencia con el anuncio de la JDBR de noviembre pasado. La moderación de la tendencia alcista de la inflación que se observó en enero, y especialmente en febrero, contribuirá a reforzar esta revisión de expectativas de inflación, y ayudará a cumplir los objetivos propuestos. Luego de registrarse una inflación del 5,6% a finales de 2021, la inflación mantuvo una tendencia alcista a lo largo de 2022 debido a las presiones inflacionarias tanto de origen externo, asociadas con las secuelas de la pandemia y las consecuencias del conflicto bélico en Ucrania, como de origen interno, resultantes de: el fortalecimiento de la demanda local; los procesos de indexación de precios estimulados por el aumento de las expectativas de inflación; las afectaciones a la producción de alimentos provocadas por el paro de mediados de 2021, y el traspaso de la depreciación a los precios. Los aumentos del salario mínimo del 10% en 2021 y del 16% en 2022, que en ambos casos superaron la inflación observada y el incremento de la productividad, acentuaron los procesos de indexación al haber establecido un elevado referente de ajuste nominal. De esta forma, la inflación total aumentó al 13,1% a finales 2022. La variación anual de alimentos, que subió del 17,2% al 27,8% entre esos dos años, fue el factor que más influyó en la aceleración del Índice de Precios al Consumidor (IPC). Otro rubro que contribuyó de manera importante a las alzas de precios fue el de regulados, cuya variación anual aumentó del 7,1% en diciembre de 2021 al 11,8% a finales de 2022. Por su parte, la medida de inflación básica sin alimentos ni regulados subió del 2,5% al 9,5% entre finales de 2021 y finales de 2022. El aumento sustancial de la inflación básica muestra que la presión inflacionaria se extendió a la mayoría de los rubros de la canasta familiar, lo cual es característico de procesos inflacionarios con una indexación de precios generalizada, como ocurre en Colombia. La política monetaria empezó a reaccionar tempranamente a estas presiones inflacionarias. Fue así como a partir de su sesión de septiembre de 2021 la JDBR inició un cambio progresivo de la postura de la política monetaria a partir del mínimo histórico del 1,75% de la tasa de interés de política al cual se había llegado para estimular la recuperación de la economía. Este proceso de ajuste prosiguió sin interrupción a lo largo de 2022 y hasta inicios de 2023, cuando la tasa de política monetaria alcanzó el 12,75% en enero pasado, con lo cual acumuló un incremento de 11 puntos porcentuales (pp). El público y los mercados se han mostrado sorprendidos de que la inflación continuara aumentando, a pesar de los significativos incrementos de la tasa de interés. Pero como lo ha explicado la JDBR en sus diversas comunicaciones, la política monetaria actúa con rezago. Así como en 2022 la actividad económica se recuperó hasta alcanzar un nivel superior al de prepandemia, impulsada, entre otros factores, por el estímulo monetario otorgado durante el período de pandemia y de los meses subsiguientes, así también los efectos de la actual política monetaria restrictiva se irán dando paulatinamente, lo que permite esperar que hacia finales de 2024 la tasa de inflación converja hacia el 3%, como es el propósito de la JDBR. Los resultados de la inflación en enero y febrero de este año mostraron incrementos marginales decrecientes (13 pb y 3 pb respectivamente), en comparación con la variación observada en diciembre (59 pb). Esto sugiere que se aproxima un punto de inflexión en la tendencia de la inflación. En otros países de América Latina, como Chile, Brasil, Perú y México, la inflación llegó a su techo y ha empezado a descender lentamente, aunque con algunos altibajos. Es previsible que en Colombia ocurra un proceso similar durante los próximos meses. El descenso previsto de la inflación en 2023 obedecerá, entre otros factores, a las menores presiones de costos externos por cuenta de la progresiva normalización de las cadenas de suministro, a la superación de los choques de oferta por razones de clima y por los bloqueos viales de años anteriores, lo que se reflejará en menores ajustes en los precios de los alimentos, como ya se observó en los primeros dos meses del año y, por supuesto, al efecto rezagado de la política monetaria. El proceso de convergencia de la inflación a la meta será gradual y se extenderá más allá de 2023. Dicho proceso se facilitará si se revierten las presiones a la devaluación, para lo cual resulta esencial que se continúe consolidando la sostenibilidad fiscal y se eviten mensajes en diferentes frentes de la política pública que generan incertidumbre y desconfianza. _______________________________________ 1 Este Informe al Congreso contiene el recuadro 1 que resume la trayectoria del Banco de la República en estos 100 años. Adicionalmente, con auspicio del Banco, varios libros que profundizan diversos aspectos de la historia de esta institución fueron publicados en años recientes. Véase, por ejemplo: Historia del Banco de la República 1923-2015; Tres banqueros centrales; Junta Directiva del Banco de la República: grandes episodios en 30 años de historia; Banco de la República : 90 años de la banca central en Colombia. 2 Es por ello que una menor inflación se ha reflejado en la reducción de la desigualdad del ingreso medida a través del coeficiente de Gini al pasar de 58,7 en 1998 a 51,3 en el año previo a la pandemia. 3 Véase Gómez Javier, Uribe José Darío, Vargas Hernando (2002). “The Implementation of Inflation Targeting in Colombia”. Borrador de Economía, núm. 202, marzo, disponible en: https://repositorio.banrep.gov.co/handle/20.500.12134/5220 4 Véase López-Enciso Enrique A.; Vargas-Herrera Hernando y Rodríguez-Niño Norberto (2016). “La estrategia de inflación objetivo en Colombia. Una visión histórica”, Borrador de Economía, núm. 952. https://repositorio.banrep.gov.co/handle/20.500.12134/6263 5 Según el FMI, la variación porcentual de los precios al consumidor entre 2021 y 2022 pasó del 3,1 % al 7,3 % para las economías avanzadas, y del 5,9 % al 9,9 % para las economías de mercados emergentes y en vías de desarrollo. 6 https://www.banrep.gov.co/es/noticias/junta-directiva-banco-republica-reitera-meta-inflacion-3