Academic literature on the topic 'Tool wear rate'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Tool wear rate.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Tool wear rate"
1
Zhang, Ziqi, Zhanqiang Liu, Xiaoping Ren, and Jinfu Zhao. "Prediction of Tool Wear Rate and Tool Wear during Dry Orthogonal Cutting of Inconel 718." Metals 13, no. 7 (2023): 1225. http://dx.doi.org/10.3390/met13071225.
Full textAbstract:
A new prediction method was proposed based on the positive feedback relationship between tool geometry and tool wear rate. Dry orthogonal cutting of Inconel 718 was used as a case study. Firstly, tool wear rate models and a tool wear prediction flowchart were proposed. Secondly, the evolution of the tool geometry during tool wear was analyzed considering the combined effect of tool crater wear and tool flank wear. Thirdly, the evolution of the cutting temperature, normal stress and tool–chip relative sliding velocity on the tool wear surface was studied, the evolution of the tool wear rate during tool wear was revealed. Finally, the evolution of the tool geometry and tool wear rate during tool wear were applied to the tool wear prediction method to accurately predict the tool wear. The prediction error of KT is less than 15% in comparison with the experimental results. The tool wear prediction method in this paper is helpful to improve the prediction accuracy of tool crater wear.
2
Meng, Xinxin, Youxi Lin, Shaowei Mi, and Pengyu Zhang. "The Study of Tool Wear Mechanism Considering the Tool–Chip Interface Temperature during Milling of Aluminum Alloy." Lubricants 11, no. 11 (2023): 471. http://dx.doi.org/10.3390/lubricants11110471.
Full textAbstract:
ADC12 aluminum alloy has been widely used in the aerospace, ship, and automotive fields because of its high specific strength, excellent die-casting performance, and wear resistance. Adhesion wear is the main wear mechanism of high-speed milling ADC12 aluminum alloy. The most important factor affecting adhesion wear is the tool–chip interface friction, which is directly manifested in the tool–chip interface temperature. Therefore, the temperature variation during the milling of aluminum alloy is analyzed using a temperature field model and infrared temperature measurement technology. Then, the tool wear morphology and the tool wear land width are observed using a scanning electron microscope. Finally, the tool wear mechanism considering the tool–chip interface temperature is discussed. The tool–chip interface temperature is related to the friction angle, tool–chip contact length, and friction force at the rake face, which increases first and then decreases as the cutting speed and feed rate increase. During the formation of the adhesive layer, the tool–chip interface temperature increases, the change rate of the cutting force and the tool wear rate increase, and adhesion, oxidation, and abrasive and delamination wear are generated on the tool surface. With the increase in temperature, the tool wear rate increases, the molten adhesive layer on the tool surface is accompanied by crack propagation, and adhesion wear, oxidation wear, and abrasive wear occur on the tool surface.
3
Parkash, Ved, and Deepak Kumar. "Effect of Powder Mixed Dielectric Medium on Tool Wear Rate in EDM." International Journal of Scientific Research 2, no. 2 (2012): 107–9. http://dx.doi.org/10.15373/22778179/feb2013/38.
Full text
4
Castro, Fernando Luiz, Denis Boing, and Rolf Bertrand Schroeter. "Tool Performance Assessment based on Three-Dimensional Tool Wear Rate." Procedia CIRP 77 (2018): 638–41. http://dx.doi.org/10.1016/j.procir.2018.08.188.
Full text
5
Xie, L. J., D. Zheng, C. Schmidt, and J. Schmidt. "Estimate of Tool Wear in Milling Operation Based on “Differential” Wear Rate Model." Applied Mechanics and Materials 10-12 (December 2007): 786–90. http://dx.doi.org/10.4028/www.scientific.net/amm.10-12.786.
Full textAbstract:
Many research show that in metal cutting process wear rate is dependent on the cutting process variables such as temperature at tool face, contact pressure (normal stress) and relative sliding velocity at tool/chip and tool/work interface; their relationship is described by “differential” wear rate model. Based on this “differential” wear rate model, a method to estimate tool wear in milling operation is proposed and the cutting process variables are predicted by performing chip formation analysis with FEM code ABAQUS/Explicit and heat transfer analysis with ABAQUS/Standard. The implementation is exemplified by estimating tool wear of carbide tools in milling of Ck45 work. Both progressive flank wear and crater wear profile are estimated.
6
Zhou, Zhi Min, Xiao Yan Li, Yuan Xin Qu, and Jian Na. "Tool Wear of Diamond Tools in Ultrasonic Vibration Turning Titanium Alloys." Applied Mechanics and Materials 229-231 (November 2012): 517–20. http://dx.doi.org/10.4028/www.scientific.net/amm.229-231.517.
Full textAbstract:
Titanium alloys, as difficult-to-cut materials, have poor machinability due to their superior mechanical properties, heat resistance and corrosion resistance. High cutting temperature and great cutting force that will greatly accelerate tool wear often occurs in titanium alloys cutting process. In this paper, an ultrasonic vibration turning method was used to lower diamond tool wear during TC4 titanium alloy turning process. Ultrasonic vibration turning tests were carried out with various cutting parameters. Experimental results indicated that there’s a significant reduction of the wear rate of diamond tools by means of ultrasonic vibration in TC4 turning process. For ultrasonic vibration turning, spindle speed, the amplitude and frequency of vibration of the tool are the greatest impact of tool wear, followed by feed rate, then the cutting depth.
7
Sagar, Chithajalu Kiran, Amrita Priyadarshini, Amit Kumar Gupta, and Devanshi Mathur. "Experimental investigation of tool wear characteristics and analytical prediction of tool life using a modified tool wear rate model while machining 90 tungsten heavy alloys." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 235, no. 1-2 (2020): 242–54. http://dx.doi.org/10.1177/0954405420933113.
Full textAbstract:
Tungsten heavy alloys are widely used in the manufacturing of weights for aircraft, missiles, boats and race cars; penetrators; radiation shielding; and radioisotope containers. Manufacturing these components needs machining as a secondary operation. Since tungsten heavy alloys are difficult to machine, the in-depth analysis of tool wear growth and mechanism during machining of these alloys becomes essential. Hence, this work focuses on the experimental study of flank wear growth and its effect on other machining outputs for two different tool geometries (−5° and 2° rake angles) during turning of 90 tungsten heavy alloys. The predominant wear mechanism was identified as adhesion based on scanning electron microscopic analysis. Finally, three commonly used analytical tool wear rate models and one newly proposed model (modified Zhao model) were utilized for the prediction of flank wear growth and tool life. It was observed that the modified Zhao model could predict tool flank wear fairly well within error percentage of 4%–7% and thus could be used as a benchmark while machining difficult-to-cut alloys.
8
Dureja, J. S., V. K. Gupta, V. S. Sharma, and M. Dogra. "Wear mechanisms of coated mixed-ceramic tools during finish hard turning of hot tool die steel." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 224, no. 1 (2009): 183–93. http://dx.doi.org/10.1243/09544062jmes1691.
Full textAbstract:
The present study aims to investigate the wear mechanisms of a TiN-coated mixed ceramic tool prevalent under different machining conditions during hard turning of hot tool die steel. The different wear mechanisms observed are abrasion wear at low cutting speed, low feed rate, and highest work piece hardness; formation of protective layer and built-up edge (BUE) resulting from tribochemical reactions between constituents of tool and work piece material at moderate speed. High temperature accompanied by high cutting speed resulted in the removal of the protective layer and suppressed the BUE formation. Hard carbide particles of work material at a higher feed rate severely gouged the tool flank land. Chipping and brittle fractures were observed at very low and high depth of cut. Adhesion of work piece material followed by plastic deformation and notching was clearly visible at low work piece hardness. The influence of cutting speed, feed rate, depth of cut, and work piece hardness on the progressive tool flank wear, and flank wear rate (VBr-μm/km) in the steady wear region was also analysed.
9
Dureja, J. S., V. K. Gupta, V. S. Sharma, and M. Dogra. "Wear mechanisms of TiN-coated CBN tool during finish hard turning of hot tool die steel." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 224, no. 4 (2009): 553–66. http://dx.doi.org/10.1243/09544054jem1664.
Full textAbstract:
The aim of the present investigation was to identify the wear mechanisms of TiN-coated CBN tools prevalent under different machining conditions during hard turning of hot tool die steel. The different wear mechanisms observed were abrasion wear at low cutting speed, low feed rate, and high workpiece hardness; formation of a transferred layer resulting from tribochemical reactions between constituents of the tool and workpiece material at high speed; and the formation of built-up edges at moderate cutting speed. Hard carbide particles of the work material at higher feed rate severely abraded the tool flank land, resulting in shallow grooves due to the detachment of CBN grains. At greater depth of cut, the built-up edges and transferred layer reduced friction and tool wear. Excessive adhesion of workpiece material followed by plastic deformation and notching were clearly visible at low workpiece hardness (47 HRC). The influence of cutting speed, feed rate, depth of cut, and workpiece hardness on the progressive tool flank wear, i.e. flank wear rate (VBr, μm/mm) in the steady wear region, was also analysed. The flank wear rate was observed to decrease with increase in cutting speed, depth of cut, and workpiece hardness, but after an initial decrease it increased with increase in feed rate.
10
Mudzaffar, Raqibah Najwa, Hanani Hani Mohd Khairy, Nur Khairunnisa Mohd Zaki, et al. "Comparative Study on the Performance of ZTA Cutting Tool with the Addition of Different Particle Size of MgO Additive." Materials Science Forum 1010 (September 2020): 181–86. http://dx.doi.org/10.4028/www.scientific.net/msf.1010.181.
Full textAbstract:
This paper investigated the performance of ZTA cutting tool with the addition of different particle size of MgO additive. Therefore, the objective of this research is to compare the effects of machining parameters on tool wears of ZTA cutting tools added with micro and nanoparticle of MgO. The experiments were conducted using BridgePort-Romi Powerpath CNC machine using a tool holder Sandvik Coromant (CoroTurn CCLNR 164D-4) to hold the cutting tools properly. The parameters are set up as cutting speeds used between range 354 to 472 m/min, feed rate from 0.1 to 0.5 mm/rev with a constant depth of cut of 0.2 mm. Three types of wear were analyzed which are flank wear, crater wear and tool chipping. Flank wear and crater wear images captured using measuring microscope (NIKON MM-400/L) and the crater wear areas are analyzed using MatLab programming software. Tool chipping is observed via SEM (JEOL JSM-5600). The experimental result shows that flank wear and crater wear increase when cutting speed and feed rate increase. ZMN cutting tool shows lower value of flank wear at 0.143 mm and 3.741 mm2 for crater wear than ZMM, 0.321 mm and 3.808 mm2 respectively. On the contrary, cutting speed did not affect the tool chipping severely as feed rate. Moreover, ZMN also shows that the tool breakage occurred severely than ZMM due to the high load on the tool nose.
Dissertations / Theses on the topic "Tool wear rate"
1
Huang, Yong. "Predictive modeling of tool wear rate with application to CBN hard turning." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/16395.
Full text
2
Ersvik, Erik, and Roj Khalid. "Milling in hardened steel - a study of tool wear in conventional- and dynamic milling." Thesis, Uppsala universitet, Tillämpad materialvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-255646.
Full textAbstract:
Milling is a commonly used machining process where a rotating cutter removes material from the workpiece. In recent years, attention has been turned towards so called dynamic milling methods which differ from the conventional way of milling. Dynamic milling normally uses, as opposed to the conventional way, more of the axial cutting edge, smaller radial depth of cut, significantly higher cutting speed and feed per tooth. The method has demonstrated potential to save both time and money under specific circumstances, for manufacturing companies.This thesis was conducted at ISCAR Sverige AB in Uppsala, Sweden. ISCAR Metalworking is a full service supplier of carbide cutting tools. The objective is to establish if there are benefits with dynamic milling methods with regard to material removal rate and lifetime of the tool by experimentally investigating and comparing tool wear that occur with conventional- and dynamic milling methods in hardened steels. Tools used were ISCAR’s MULTI-MASTER end mills, MM A and MM B, and the hardened steels were Hardox 600 and Dievar. Analysis was performed by using a USB-microscope, scanning electron microscope (SEM) and a Wyko-profilometer. The results of this study show that dynamic milling parameters can give several benefits regarding tool life and material removal rate. When machining in Hardox 600 and Dievar, both end mills were able to achieve a higher material removal rate and lifetime with dynamic parameters compared to more conventional ones. MM A outperformed MM B in Dievar, but the results were reversed in Hardox, MM B performed better. Results from the profilometry analysis showed that in Dievar, the dynamic parameters generated a smoother surface while the surface results from Hardox were more equivocal. The main conclusion was that milling with dynamic parameters is generally more advantageous and should be utilised, if possible.
3
Taylor, Matthew H. "Defining a Model for Tool Consumption Rate on Asphalt Reclamation Machines." BYU ScholarsArchive, 2006. https://scholarsarchive.byu.edu/etd/1293.
Full textAbstract:
Asphalt and concrete reclamation machines are used to cut roadways when a repair is required. The performance of these machines can affect the quality of road repairs, and cost/profitability for both contractors and governments. We believe that several performance characteristics in reclamation machines are governed by the placement and pattern of cutting picks on the cutter head. Previous studies, focused on mining and excavation applications, have shown strong correlation between placement and wear. The following study employs a screening experiment (observational study) to find significant contributors to tool wear, in applications of asphalt milling or reclamation. We have found that picks fail by two primary modes: tip breakage, and body abrasive wear. Results indicate that the circumferential spacing of a bit, relative to neighboring bits, has the strongest effect on tip breakage. We have also shown that bit skew angle has a large positive effect on body abrasive wear.
4
Bonilla, Hernández Ana Esther. "Analysis and direct optimization of cutting tool utilization in CAM." Licentiate thesis, Högskolan Väst, Forskningsmiljön produktionsteknik(PTW), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-8672.
Full textAbstract:
The search for increased productivity and cost reduction in machining can be interpreted as the desire to increase the material removal rate, MRR, and maximize the cutting tool utilization. The CNC process is complex and involves numerous limitations and parameters, ranging from tolerances to machinability. A well-managed preparation process creates the foundations for achieving a reduction in manufacturing errors and machining time. Along the preparation process of the NC-program, two different studies have been conducted and are presented in this thesis. One study examined the CAM programming preparation process from the Lean perspective. The other study includes an evaluation of how the cutting tools are used in terms of MRR and tool utilization. The material removal rate is defined as the product of three variables, namely the cutting speed, the feed and the depth of cut, which all constitute the cutting data. Tool life is the amount of time that a cutting tool can be used and is mainly dependent on the same variables. Two different combinations of cutting data might provide the same MRR, however the tool life will be different. Thereby the difficulty is to select the cutting data to maximize both MRR and cutting tool utilization. A model for the analysis and efficient selection of cutting data for maximal MRR and maximal tool utilization has been developed and is presented. The presented model shortens the time dedicated to the optimized cutting data selection and the needed iterations along the program development.
5
Aris, Najmil Faiz Mohamed. "Surfaces functionality of precision machined components : modelling, simulation, optimization and control." Thesis, Brunel University, 2008. http://bura.brunel.ac.uk/handle/2438/5092.
Full textAbstract:
This research develops an analytical scientific approach for investigating the high precision surface generation and the quantitative analysis of the effects of direct factors in precision machining. The research focuses on 3D surface characterization with particular reference to the turning process and associated surface generation. The most important issue for this research is surface functionality which is becoming important in the current engineering industry. The surface functionality should match with the characterization parameters of the machined surface, which can be expressed in formula form as proposed in chapter 4. Modelling and simulation are extensively used in the research. The modelling approach integrates the cutting forces model, thermal mode% vibration model, tool wear model, machining system response model and surface topography model. All of those models are integrated as a whole model. The physical model with such as direct inputs is formed. The major inputs to the model are tooling geometry and the process variables. The outputs from the modelling approach are cutting force, surface texture parameters, dimensional errors, residual stress and material removal rate. MATLAB and Simulink are used as tools to implement the modelling and simulation. According to the simulation results, it is found that the feed rate has the most profound effect on in surface generation. The influence of the vibrations between the cutting tool and the workpiece on the surface roughness may be minimised by the small feed rate and large tool nose radius. Surface functionality simulation has been developed to model and simulate the surface generation in precision turning. The surface functionality simulation model covers the material and tool wear as well. It shows that chip formation is resulted from cutting forces. Cutting trials are conducted to validate the modelling and simulation developed. There are positive results that show the agreement between the simulation and experimental results. The analysis of the results of turning trials and simulations are conducted in order to find out the effects of process variables and tooling characteristics on surface texture and topography and machining instability. From the research, it can be concluded that the investigation on modelling and simulation of precision surfaces generation in precision turning is performed well against the research objectives as proposed. Recommendations for future work are to improve the model parameters identification, including comprehensive tool wear, chip formation and using Neural Networks modelling in the engineering surface construction system.
6
Blom, Ricky J. "Production and evaluation of rapid tooling for electric discharge machining using electroforming and spray metal deposition techniques." Thesis, Queensland University of Technology, 2005. https://eprints.qut.edu.au/16014/1/Ricky_Blom_Thesis.pdf.
Full textAbstract:
To survive in today's manufacturing environments companies must push the standards of accuracy and speed to the highest levels possible. Electro Discharge Machining (EDM) has been used for over 50 years and recent developments have
seen the use of EDM become much more viable. The goal of this research is to produce and evaluate electrodes produced by different manufacturing methods.
The use of electroforming and spray-metal deposition has only recently become viable methods of producing usable rapid tooling components. The speed and accuracy as well as the cost of manufacture play a vital role in the tool and mould manufacturing process. Electroforming and spray-metal deposition offer an alternate option to traditional machining of electrodes.
Electroforming is one method of producing electrodes for EDM. The fact that electroforming can be used to produce multiple electrodes simultaneously gives it the advantage of saving on costs when multiple electrodes are needed. Spray-metal deposition offers another alternative that is much cheaper and relatively faster to manufacture.
The used of these non-traditional manufacturing methods in this research are compared to the performance of traditional solid electrodes in terms of machining time, material removal rate, tool wear rates and surface roughness at several standard machining settings.
The results of this research are presented in this thesis along with conclusions and comments on the performance of the different methods of electrode manufacture. The major findings of the research include the solid electrodes performed better than the electroformed electrodes in Material Removal Rate (MRR), Tool Wear Rate (TWR), and Surface Roughness (Ra) at all machine settings. However it was found that the production cost of the solid electrodes was six times that of the electroformed electrodes.
The production of spray metal electrodes was unsuccessful. The electrode shell walls were not an even thickness and the backing material broke through the shell making them unusable.
It is concluded that with further refinements and research, electroforming and spray metal processes will become an extremely competitive method in electrode manufacture and other rapid tooling processes.
7
Blom, Ricky J. "Production and Evaluation of Rapid Tooling for Electric Discharge Machining using Electroforming and Spray Metal Deposition Techniques." Queensland University of Technology, 2005. http://eprints.qut.edu.au/16014/.
Full textAbstract:
To survive in today's manufacturing environments companies must push the standards of accuracy and speed to the highest levels possible. Electro Discharge Machining (EDM) has been used for over 50 years and recent developments have seen the use of EDM become much more viable. The goal of this research is to produce and evaluate electrodes produced by different manufacturing methods. The use of electroforming and spray-metal deposition has only recently become viable methods of producing usable rapid tooling components. The speed and accuracy as well as the cost of manufacture play a vital role in the tool and mould manufacturing process. Electroforming and spray-metal deposition offer an alternate option to traditional machining of electrodes. Electroforming is one method of producing electrodes for EDM. The fact that electroforming can be used to produce multiple electrodes simultaneously gives it the advantage of saving on costs when multiple electrodes are needed. Spray-metal deposition offers another alternative that is much cheaper and relatively faster to manufacture. The used of these non-traditional manufacturing methods in this research are compared to the performance of traditional solid electrodes in terms of machining time, material removal rate, tool wear rates and surface roughness at several standard machining settings. The results of this research are presented in this thesis along with conclusions and comments on the performance of the different methods of electrode manufacture. The major findings of the research include the solid electrodes performed better than the electroformed electrodes in Material Removal Rate (MRR), Tool Wear Rate (TWR), and Surface Roughness (Ra) at all machine settings. However it was found that the production cost of the solid electrodes was six times that of the electroformed electrodes. The production of spray metal electrodes was unsuccessful. The electrode shell walls were not an even thickness and the backing material broke through the shell making them unusable. It is concluded that with further refinements and research, electroforming and spray metal processes will become an extremely competitive method in electrode manufacture and other rapid tooling processes.
8
Drda, David. "Technologické a ekonomické parametry řezného nástroje." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228639.
Full textAbstract:
Aim master´s thesis is analyzed technological and economical parameters of cutting tool. Firstly there are the parameters cutting tool, cutting wear, economical parameters and costs on running tools specified. In the conclusion there are reach technological and economical parameters of cutting tools analyzed and tested on practical sample. The sample is part of attachments in form programme on calculation in Excel, together with evaluation by means of graphs.
9
Dragan, Rodić. "Optimizacija procesa elektroerozivne obrade savremenih inženjerskih materijala." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2019. https://www.cris.uns.ac.rs/record.jsf?recordId=110508&source=NDLTD&language=en.
Full textAbstract:
Predmet istraživanja ove disertacije predstavlja unapređenje, modelovanje i optimizacija procesa elektroerozivne obrade (EDM) savremenih inženjerskih materijala. Prvo su predstavljene dve inovativne metode: EDM u dielektrikumu sa pomešanim prahom i EDM sa pomoćnom elektrodom, a zatim i njihova kombinacija. Za generisanje matematičkih modela primenjene su metodologija odzivne površine i alati veštačke inteligencije. U nastavku su postavljeni optimizacioni procesi određivanja ulaznih parametara sa jednom i više funkcija cilja koji su rešeni primenom klasičnih metoda optimizacije. U završnom osvrtu sprovedena je verifikacija dobijenih modela i optimalnih ulaznih parametara elektroerozivne obrade.<br>The subject of the research of this dissertation is the improvement, modeling and optimization of the electrical discharge machining (EDM) of advanced engineering materials. First, two innovation methods are presented: EDM in powder mixed dielectric fluid and EDM with assisted electrode and that their combination. The method of response surface and artificial intelligence tools were applied to generate mathematical models. The optimization problems of determining the input parameters with single and multiple target functions are solved by the application of classical optimization methods. Finally, verification of the obtained models and optimal input parameters of electrical discharge machining was carried out.
10
González, Páez Claudia Verónica. "Rendimiento, desgaste y abrasividad en excavación mecanizada de túneles en terrenos heterogéneos." Doctoral thesis, Universitat Politècnica de Catalunya, 2014. http://hdl.handle.net/10803/284200.
Full textAbstract:
Una base de datos de 33 km de registros de túnel de EPB en la zona de Barcelona se ha examinado en detalle desde el punto de vista de recambio de herramientas de corte y rendimiento de la excavación mecanizada. La base de datos incluye túneles en suelos blandos, en rocas medias y duras y en condiciones mixtas de roca y suelo. Los datos recabados incluyen registros de cambios de herramientas, operaciones de la maquina (avance, empuje, par, etc.) y propiedades geotécnicas, con un énfasis sistemático en mediciones de abrasividad de los diferentes materiales perforados. Para obtener una descripción homogénea de la abrasividad se realizaron mediciones de abrasividad del tipo LCPC en todos los materiales. Un resumen descriptivo de las principales tendencias reveladas por los datos se presenta en esta tesis. Las paradas de las máquinas durante la perforación se pueden clasificar entre aquellas debidas a un mantenimiento planificado y aquellas debidas a incidentes imprevistos. Los últimos pueden resultar ser decisivos cuando evaluamos el éxito de una perforación, aunque normalmente no son considerados en el proyecto. Uno de los aspectos más exigentes del mantenimiento desde el punto de vista operativo es el de las herramientas de corte, ya que su revisión y posible sustitución siempre implica paradas de la máquina, y como que a menudo es necesario tener acceso al frente, es con frecuencia una operación lenta y difícil. Por lo tanto, es deseable programar el mantenimiento de la cabeza de corte con la precisión máxima posible. Para llevar a cabo tal programación dos aspectos son necesarios: la identificación de ¿umbrales de desgaste¿ de las herramientas y un método que permita estimar el desgaste para cada herramienta como consecuencia de la operación. El objetivo de este estudio es investigar cómo enfrentarse a este problema cuando el medio es heterogéneo y la excavación es mecanizada mediante EPB. Se tiene en cuenta sistemáticamente la heterogeneidad geotécnica transversal y longitudinal. La heterogeneidad longitudinal se usa para segmentar la base de datos en unidades homogéneas. La heterogeneidad transversal (dentro de la sección) se estima por un conjunto de factores de impacto en la presente desarrollados FI. El concepto de energía específica (SE) fue aplicado para evaluar la eficiencia total de la excavación. Procedimientos anteriores para computar SE en excavaciones con TBM fueron adaptados a excavaciones con maquina EPB en modo cerrado. Se tienen en cuenta explícitamente el soporte del frente y el momento rotacional debido a la presión de la tierra. Varios métodos existentes para predecir la tasa de penetración y la vida útil de las herramientas se evalúan respecto a los resultados de la base de datos. Siempre que fuera necesario se realizaron recalibraciones de estos procedimientos. Basadas en un análisis sistemático de los resultados de la base de datos, se proponen nuevas relaciones de origen empírico para estimar la tasa de penetración a partir de otros parámetros operacionales y las propiedades del suelo promediadas por sección. La exactitud de algunas aproximaciones implicadas (concretamente el uso de un tiempo de vida útil equivalente) se ha encontrado razonable usando los resultados de una excavación con los datos que eran lo más exactos posibles. Las relaciones propuestas serian mayormente aplicables como puntos de partida en proyectos en los cuales la geología está compuesta de suelos y rocas blandas y donde son predominantes los frentes heterogéneos.<br>A database of 33 km of EPB tunnel records in the Barcelona area has been examined in detail from the point of view of cutting tool replacement and performance of the mechanized excavation. The database includes tunnels in soft soils, in hard and medium rocks and in mixed soil-rock conditions. Data gathered includes tool changing records, machine operation (advance, thrust, torque, etc.) and geotechnical properties, with a systematic emphasis on abrasivity measurements of the different materials perforated. To obtain a homogeneous description of abrasivity LCPC-type abrasive measurements were made in all the materials. A descriptive summary of the main trends revealed by the data is presented in this thesis.
Machine downtimes during perforation can be classified into those due to planned maintenance and those due to unforeseen incidents. The latter can turn out to be decisive when assessing the success of a perforation, even though they are not usually considered in the project. One of the most demanding aspects of maintenance from an operational point of view is that of the cutting tools, since their revision and possible substitution always involves machine stops and, since it is often necessary to have access to the face, this is frequently a slow and difficult operation. Thus, it is desirable to schedule the cutter head maintenance operations with the highest possible precision. To carry out such scheduling two aspects are necessary: the identification of ¿wear thresholds¿ of the tools and a method that allows estimating the wear for each tool as a result of the operation. The objective of this study is to investigate how to tackle this problem when the media is heterogeneous and the excavation is mechanized by EPB.
Transversal and longitudinal geotechnical heterogeneity is systematically accounted for. Longitudinal heterogeneity is used to segment the database in homogeneous units. Transversal (within section) heterogeneity is gauged by a set of newly developed impact factors FI.
The specific energy concept (SE) was applied to evaluate overall excavation efficiency. Previous procedures to compute SE in TBM drives were adapted to excavations by EPB machine in closed mode. Face support and rotational moment due to earth pressure at the front face are taken explicitly into account. Several existing methods to predict penetration rate and tool service life are evaluated against the database results. Recalibrations of these procedures were performed when required.
Based on a systematic analysis of the database results, new empirically based relations are proposed to estimate penetration rate from other operation parameters and section-averaged ground properties. The accuracy of some approximations involved (namely the use of an equivalent tool life time) has been found reasonable using the results of one drive were more exact computations were possible. The proposed relations would be mostly applicable as starting points in projects in which the geology is composed mostly of soils and soft rock and where the heterogeneous faces are predominant.
Books on the topic "Tool wear rate"
1
Dortans, Peter. Innovation Race. Murmann, 2021. http://dx.doi.org/10.59716/978-3-86774-691-5.
Full textAbstract:
Bahnen Sie sich Ihren Weg im FuE-Rennen! Das einzigartige Innovationsbuch der VDI/VDE Innovation + Technik GmbH. „Innovation Race“ zeigt anhand erfolgreicher Fallbeispiele, wie zukunftsorientierte Forschung für Innovationen in Unternehmen und Projekten konkret gelingen kann. Ein Buch voller Race Maps, in dem jeder Teilnehmer in Fallbeispielen seine Routenoptionen und seine Ziele absteckt. Hier findet der Leser die individuelle Topografie von Checkpoints, Tools und Strategien jedes Teilnehmers am Innovationsrennen. Die besondere Lesernavigation mit praxisnahen Strategien und Werkzeugen ist das Herzstück des Buches – und die Grundlage für die Ableitung allgemeingültiger Erfolgsprinzipien. Wer das Buch gelesen hat, ist in der Lage, selbst seine Roadmap kompetent zu erstellen und die entscheidenden Fragen des FuE-Managements zu beantworten: Welche Erfolgsprinzipien passen? Auf welche Checkpoints, Werkzeuge und Strategien kommt es an? Durch welche Topografie muss mein Unternehmen oder mein Projekt geführt werden? Herausgeber Peter Dortans zeigt gemeinsam mit FuE-Experten aus Wirtschaft und Forschung die Vielfalt von FuE, liefert mit allgemeingültigen Prinzipien aber auch übergeordnete Orientierung bei der Planung, Durchführung und Umsetzung von FuE-Vorhaben. Ein wegweisendes Werk, das die Essenz für nachhaltig erfolgreiches FuE-Management sichtbar macht.
2
Wade-Olson, Jeremiah. Punishing the Vulnerable. Praeger, 2019. http://dx.doi.org/10.5040/9798216003359.
Full textAbstract:
Few studies look at the treatment of those inside America’s prisons. Discussing race discrimination alongside gender, ethnic, and religious discrimination in contemporary American prisons, this book finds that correctional staff are swayed by stereotypes in their treatment of inmates The American Dream is that anyone who works hard enough can be successful. It is a dream premised on equal opportunity; however, millions of racial, ethnic, religious, and gender minorities have found their opportunities for success limited—even in prison. What accounts for the discriminatory treatment of people who are already imprisoned? Relying on national data and interviews conducted by the author, this book argues that American prisons are not a tool for justice but a tool for the persecution of the weak by the powerful. The book details how African American, American Indian, and Hispanic inmates receive harsher punishments, including solitary confinement, and fewer rehabilitative programs, such as substance abuse treatment and mental health counseling. It also examines other injustices, including how female inmates suffer from a lack of rehabilitative services, Muslim inmates are placed in solitary confinement for practicing their religious beliefs, American Indians are disproportionately punished, and undocumented immigrants are forced from prison to prison in the middle of the night.
3
Inder, Pam. Shirts, Shifts and Sheets of Fine Linen. Bloomsbury Publishing Plc, 2023. http://dx.doi.org/10.5040/9781350252998.
Full textAbstract:
Shirts, Shifts and Sheets of Fine Linen explores how the jobs of the ‘seamstress’ evolved in scope, and status, between 1600-1900. In the 17th and early 18th centuries, seamstressing was a trade for women who worked in linen and cotton, making men’s shirts, women’s chemises, underwear and baby linen; some of these seamstresses were consummate craftswomen, able to sew with stitches almost invisible to the naked eye. Few examples of their work survive, but those that do attest their skill. They took apprentices and generally made a good living by the standards of their time. However, as the ready-to-wear trade expanded in the 18th century, women who assembled these garments were also known as seamstresses, as were women employed by families to keep the household linen and in good order. By the 1840s, most seamstresses were outworkers for companies or entrepreneurs, paid unbelievably low rates per dozen for the garments they produced, notorious examples of downtrodden, exploited womenfolk. This book explores the seamstress’s change of status and the reasons for it, and hints at the resurgence of the trade today because so few 21st century women are now individually skilled at repairing and altering clothes.
4
McCallum, John. Poor Relief and the Church in Scotland, 1560-1650. Edinburgh University Press, 2018. http://dx.doi.org/10.3366/edinburgh/9781474427272.001.0001.
Full textAbstract:
This book analyses poor relief in the century or so after the Scottish Reformation of 1560. In doing so it challenges the assumption that Scottish poor relief was weak, informal and haphazard because it was run by the Protestant church rather than the state, as in England (all too often the yardstick against which Scotland is measured). Instead, the book explores the substantial welfare work carried out by Scottish parishes, and examines in detail how the system operated as well as those who benefitted from it. The rich but under-utilised parish records which are the focus of the study reveal not just the relief efforts themselves, but also provide a rare insight into the lives of poor Scots whom pre-modern historians often struggle to glimpse. The book will therefore appeal to a wide range of scholars of early modern Scotland, of poverty and its relief, and of the Reformation.
5
Ezra, Elizabeth, and Catherine Wheatley, eds. Shoe Reels. Edinburgh University Press, 2021. http://dx.doi.org/10.3366/edinburgh/9781474451406.001.0001.
Full textAbstract:
Shoe Reels examines the special relationship between shoes and cinema. The book considers the narrative and aesthetic functions of shoes, asking why they are so memorable, and what their wider cultural resonance might be. Written by experts from a range of disciplines, including film and television studies, philosophy, history, and fashion, this collection covers cinema from its origins to the present day, and spans a global range of films from the United States, Europe, Africa and Asia. Besides protecting the feet, shoes contribute to the performance of gender; they indicate aspects of personality, sexuality, race, ethnicity and social class; and they serve as tools of seduction. As objects designed for the body, shoes also affirm the materiality of individual bodies and the endurance of the human body itself when physical presence has been progressively de-emphasised, first with the advent of technical reproducibility (printing, photography, cinema, radio and the like), and now with the rise of digital technology in the virtual era. The very materiality of shoes—the fact that they are things—is what makes them ripe for analysis. Shoes humanise, setting people apart from non-human animals, but they can also serve to dehumanise. Objects par excellence of hyper-consumption, shoes are situated at the crossroads of sexual fetishism and commodity fetishism. Shoes are clearly more than just good to wear, then: to paraphrase Claude Lévi-Strauss, they are also good to think.
6
Fitzpatrick, Kevin M., and Matthew L. Spialek. Hurricane Harvey's Aftermath. NYU Press, 2020. http://dx.doi.org/10.18574/nyu/9781479800735.001.0001.
Full textAbstract:
Early June begins the Southern Hemisphere hurricane season. Stretching into November, it can often be a time of weary waiting and cautious optimism for coastal residents. Clear skies and calm seas can quickly give way to disaster. On August 27, 2017, a Category 4 hurricane (Harvey), targeting the Texas Gulf Coast and packing winds of over 130 miles per hour, wreaked havoc and created a path of destruction with bands of rain that seemingly went on forever. Lives were lost, neighborhoods devastated, resiliency cracked; yet people continued helping each other, and the recovery process began. Fitzpatrick and Spialek tell a complicated story of heartache, destruction, resiliency, recovery, and hope. Through over 300 interviews from Hurricane Harvey survivors living along the Texas Gulf Coast, their stories tell an all-too-familiar tale. Interviewing survivors with diverse displacement experiences, the authors create a narrative around who, what, where, and why residents sought refuge in shelters, hotels, and other alternative locations. Some residents have since moved back. Others have been rebuilding for months and even years. And there are some residents who will never return home. Their stories, circumstances, and insight into the recovery processes are all very different, yet intimately tied together through an understanding of how race and place come to define their experiences. This book tells survivors’ stories while emphasizing that who those survivors were and where they lived had a major impact on these tales of destruction, resiliency, and recovery.
7
McDonnell, Erin Metz. Patchwork Leviathan. Princeton University Press, 2020. http://dx.doi.org/10.23943/princeton/9780691197364.001.0001.
Full textAbstract:
Corruption and ineffectiveness are often expected of public servants in developing countries. However, some groups within these states are distinctly more effective and public oriented than the rest. Why? This book explains how a few spectacularly effective state organizations manage to thrive amid general institutional weakness and succeed against impressive odds. Drawing on the Hobbesian image of the state as Leviathan, the book argues that many seemingly weak states actually have a wide range of administrative capacities. Such states are in fact patchworks sewn loosely together from scarce resources into the semblance of unity. The book demonstrates that when the human, cognitive, and material resources of bureaucracy are rare, it is critically important how they are distributed. Too often, scarce bureaucratic resources are scattered throughout the state, yielding little effect. The book reveals how a sufficient concentration of resources clustered within particular pockets of a state can be transformative, enabling distinctively effective organizations to emerge from a sea of ineffectiveness. The book offers a comprehensive analysis of successful statecraft in institutionally challenging environments, drawing on cases from contemporary Ghana and Nigeria, mid-twentieth-century Kenya and Brazil, and China in the early twentieth century. The book explains how these highly effective pockets differ from the Western bureaucracies on which so much state and organizational theory is based, providing a fresh answer to why well-funded global capacity-building reforms fail—and how they can do better.
8
Ferro, Charles J., and Khai Ping Ng. Recommendations for management of high renal risk chronic kidney disease. Edited by David J. Goldsmith. Oxford University Press, 2015. http://dx.doi.org/10.1093/med/9780199592548.003.0099.
Full textAbstract:
Poorer renal function is associated with increasing morbidity and mortality. In the wider population this is mainly as a consequence of cardiovascular disease. Renal patients are more likely to progress to end-stage renal disease, but also have high cardiovascular risk. Aiming to reduce both progression of renal impairment and cardiovascular disease are not contradictory. Focusing on the management of high-risk patients with proteinuria and reduced glomerular filtration rates, it is recommended that blood pressure should be kept below 140/90, or 130/80 if proteinuria is > 1 g/24 h (protein:creatinine ratio (PCR) >100 mg/mmol or 0.9 g/g). These targets may be modified according to age and other factors. Angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor antagonists should form part of the therapy for patients with proteinuria > 0.5 g/24 h (PCR > 50 mg/mmol or 0.45 g/g). Use of ACEIs or angiotensin receptor blockers in patients with lower levels of proteinuria may be indicated in some patient groups even in the absence of hypertension, notably in diabetic nephropathy. Evidence that other agents that reduce proteinuria bring additional benefits is weak at present. The best studies of ‘dual-blockade’ with various combinations of ACEIs, ARBs, and renin inhibitors have shown additional hazard with little evidence of additional benefit. Hyperlipidaemia—regardless of lipid levels, statin therapy is indicated in secondary cardiovascular prevention, and in primary prevention where cardiovascular risk is high, noting that current risk estimation tools do not adequately account for the increased risk of patients with CKD. There is not substantial evidence that lipid lowering therapy impacts on average rates of loss of GFR in progressive CKD. Non-drug lifestyle interventions to reduce cardiovascular risk, including stopping smoking, are important for all. Acidosis—in more advanced CKD it is justified to treat acidosis with oral sodium bicarbonate. Diet—sodium restriction to < 100 mmol/day (6 g/day) and avoidance of excessive dietary protein are justified in early to moderate CKD. Recommendations to limit levels of protein to 0.8 g/kg body weight are suggested by some, but additional protective effects of this are likely to be slight in patients who are otherwise well managed. Low-protein diets may carry some risk. Lower-protein diets may however be used to prevent symptoms in advanced CKD not treated by dialysis.
Book chapters on the topic "Tool wear rate"
1
Sundriyal, Sanjay, Ravinder Singh Walia, and Vipin. "Powder Mixed Near Dry Electric Discharge Machining Parameter Optimization for Tool Wear Rate." In Lecture Notes on Multidisciplinary Industrial Engineering. Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-32-9471-4_1.
Full text
2
Kumar, Rakesh, Anand Pandey, Pooja Sharma, Ashish Goyal, and Satish Namdev. "Influence of Process Parameters on Tool Wear Rate for Rotary Cu Tool Electrode in Electrical Discharge Drilling." In Lecture Notes on Multidisciplinary Industrial Engineering. Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-4619-8_14.
Full text
3
Parashar, Vishal, Shubham Jain, and P. M. Mishra. "Optimization of Tool Wear Rate Using Artificial Intelligence–Based TLBO and Cuckoo Search Approach." In Artificial Intelligence, Internet of Things (IoT) and Smart Materials for Energy Applications. CRC Press, 2022. http://dx.doi.org/10.1201/9781003220176-2.
Full text
4
Thallapalli, Nagaveni, Vinay Kumar Goud Balne, and T. S. R. V. Padmalatha. "Modelling of Surface Roughness and Tool Wear Rate During Turning of AISI 202 Stainless Steel." In Learning and Analytics in Intelligent Systems. Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-24314-2_88.
Full text
5
Singh, Ranjit, Ravi Pratap Singh, and Rajeev Trehan. "Investigation of Machining Rate and Tool Wear in Processing of Fe-Based-SMA Through Sinking EDM." In Lecture Notes on Multidisciplinary Industrial Engineering. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-73495-4_30.
Full text
6
Quang, Nguyen Huu, Tran Thanh Hoang, Nguyen Huu Luan, et al. "Effects of EDM Parameters on Surface Roughness and Electrode Wear Rate When Processing SKD11 Tool Steel." In Advances in Engineering Research and Application. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92574-1_38.
Full text
7
Nandurkar, Santosh, Sachin Kulkarni, Tushar Hawal, Niranjan Pattar, and Nagaraj Kelageri. "Investigation of Effect of EDM Process Variables on Material Removal Rate and Tool Wear Rate in Machining of EN19 Steel Using Response Surface Methodology." In Lecture Notes in Mechanical Engineering. Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-2278-6_7.
Full text
8
Elias, Jiju V., S. Asams, and Jose Mathew. "Finite Element Simulation and Experimental Investigations to Predict Tool Flank Wear Rate During Microturning of Ti–6Al–4V Alloy." In Advances in Simulation, Product Design and Development. Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-32-9487-5_40.
Full text
9
Phan, Nguyen Huu, Vu Ngoc Pi, Nguyen Quoc Tuan, et al. "Tool Wear Rate Analysis of Uncoated and AlCrNi Coated Aluminum Electrode in EDM for Ti-6Al-4 V Titanium Alloy." In Advances in Engineering Research and Application. Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-64719-3_91.
Full text
10
Rouniyar, Arun Kumar, and Pragya Shandilya. "Analysis and Optimization of Tool Wear Rate in Magnetic Field-Assisted Powder-Mixed Electrical Discharge Machining of Al6061 Alloy Using TLBO." In Lecture Notes on Multidisciplinary Industrial Engineering. Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-32-9072-3_42.
Full textConference papers on the topic "Tool wear rate"
1
Kuttolamadom, Mathew, Parikshit Mehta, Laine Mears, and Thomas Kurfess. "The Correlation of Volumetric Tool Wear and Wear Rate of Machining Tools With the Material Removal Rate of Titanium Alloys." In ASME 2012 International Manufacturing Science and Engineering Conference collocated with the 40th North American Manufacturing Research Conference and in participation with the International Conference on Tribology Materials and Processing. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/msec2012-7338.
Full textAbstract:
The objective of this paper is to assess the correlation of volumetric tool wear (VTW) and wear rate of carbide tools on the material removal rate (MRR) of titanium alloys. A previously developed methodology for assessing the worn tool material volume is utilized for quantifying the VTW of carbide tools when machining Ti-6Al-4V. To capture the tool substrate response, controlled milling experiments are conducted at suitable corner points of the feed-speed design space for constant stock material removal volumes. For each case, the tool material volumes worn away, as well as the corresponding volumetric wear profile evolution in terms of a set of geometric coefficients are quantified — these are then related to the MRR. Further, the volumetric wear rate and the M-ratio (volume of stock removed to VTW), which is a measure of the cutting tool efficiency, are related to the MRR — these provide a tool-centered optimal MRR in terms of profitability. This work not only elevates tool wear from a 1-D to 3-D concept, but helps in assessing machining economics from a stock material removal efficiency perspective as well.
2
Srinivas, J., Rao Dukkipati, V. Sreebalaji, and K. Ramakotaih. "Tool-Wear Monitoring and Control." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-80799.
Full textAbstract:
This paper presents, a control methodology based on experimental data of the tool wear as a function of cutting variables. In automatic machine tools there is strong need to control the tool wear by adjustment of the cutting parameters. In this connection, a control system, which can adjust the cutting parameters for a desired wear rate, is necessary. A regression relation is also established between the flank-wear and the cutting parameters. An inversely trained neural network model, which supplies the modified values of the cutting parameters, is used as a controller. The results are shown in the form of tables and graphs.
3
Huang, Yong, and Steven Y. Liang. "CBN Tool Wear Modeling in Finish Hard Turning." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-42165.
Full textAbstract:
The cubic boron nitride (CBN) cutting tools are commonly used for single point turning of hardened materials. The wear behavior and tool life of CBN cutters are important issues in order for hard turning to be a viable technology in view of the high cost of CBN cutting tools and the cost of down-time for tool change. The objective of this study is to develop a methodology to model the rate of CBN tool wear on both the flank and rake faces. The model can serve both as a basis to guide the design of CBN tool geometry and to optimize cutting parameters in finish hard turning. First, the kinematics, stress distribution, and temperature variation on the tool flank and rake faces are formulated. Subsequently, the wear volume loss is modeled as functions of cutting temperature, stress, and other process information based on the consideration of main wear mechanisms of abrasion, adhesion, and diffusion. Then, flank/crater wear rates are predicted in terms of tool/work material properties and cutting configuration. Finally, based on the calibrated wear coefficients in independent tests, the proposed models are experimentally validated in finish turning hardened 52100 bearing steel using a low CBN content insert. The model predictions agree with the measurements in terms of the behavior of stable growths of wear land and crater. The adhesion is found to be the dominating wear mechanism over the range of cutting parameters examined.
4
Hanson, Craig, Xingbang Chen, Muhammad P. Jahan, Jianfeng Ma, and Gregory K. Arbuckle. "Investigating the Effect of Tool Coating on Cutting Forces and Tool Wear During Micro-Milling of Polycarbonate Glass." In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-87441.
Full textAbstract:
Polycarbonate glass is one of the most widely used materials in the optical industries for making impact resistance lenses. Besides optical applications, polycarbonate glass has found applications in automotive and biomedical industries. The objective of this study is to investigate the effect of tool coating on the reduction of tool wear and cutting forces during micro-milling of polycarbonate glass. Both numerical modeling and experimental investigation have been carried out to investigate the effectiveness of various tool coatings on the carbide tool in minimizing the cutting forces, and hence tool wear. A series of experiments were conducted using CNC micro-milling of polycarbonate glass by varying feed rate, depth of cut, and tool coating. The three types of cutting tools used in this study were uncoated, titanium nitride (TiN) coated, and titanium aluminum nitride (TiAlN) coated tungsten carbide tools. The cutting forces have been recorded using the Kistler force dynamometer and the tool wear were analyzed using scanning electron microscope (SEM). It was found that all tools had reduced instances of failure, chipping, and abrasion at a moderately higher feed rate and depth of cut. Both very low and high feed rate were found to result in comparatively higher tool wear. The cutting forces increased with an increase of depth of cut, except for the TiAlN coated tool in some instances. With the increase of feed rate, the cutting forces gradually increased or stayed relatively constant across all depths of cut. It was found that the TiAlN coated tool reduced the amount of tool wear and cutting force across all feed rates and depths of cut. There is also a critical depth of cut around 0.3–0.5 mm and feed rate around 576–768 mm/min that reduced the amount of tool wear for the micro-milling of polycarbonate glass. Finally, the numerical modeling and simulation results of cutting forces were found to be in good agreement with the experimental cutting forces and the validated FEM models were then used to predict the cutting forces for higher spindle speed.
5
Song, Xiaoqi, Yukio Takahashi, Tohru Ihara, and Weiming He. "Effects of the Size of Built-Up Layer on the Wear of Uncoated Cemented Carbide Tools in Dry Cutting of SUS304 Stainless Steel." In JSME 2020 Conference on Leading Edge Manufacturing/Materials and Processing. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/lemp2020-8549.
Full textAbstract:
Abstract Built-up layer (BUL) formed on the tool rake face during cutting has the tool protective effect. As BUL can change the shape of tool resulting in variation of rake angle and edge radius during cutting, it also has significant influences on the cutting phenomena such as tool wear, cutting forces and surface integrity. SUS304 stainless steel is very difficult to cut, leading to the rapid tool wear and poor surface quality. It also has a high tendency to form BUL during cutting due to its high work hardening rate and high chemical affinity. To actively and purposely utilize BUL, the effects of the size of BUL on the wear of uncoated cemented carbide tools in dry cutting of SUS304 were investigated using experimental and analytical methods in this study. The cutting parameters were chosen to induce the stable BUL formation. After cutting, the worn cutting tools were analyzed using the laser confocal microscopy and scanning electron microscopy. It was confirmed that BUL can reduce the tool flank wear rate in the steady-state wear when its height is equal to or less than the uncut chip thickness. The results also showed that BUL formed at cutting speed 40 m/min can not only reduce the tool flank wear rate but also induce a significant improvement in cutting forces and surface integrity. Meanwhile, using the obtained experimental results and proposed model, simulation was conducted to evaluate the effects of the size of BUL on the tool flank wear formation. It was confirmed that BUL, especially when its height is close to the uncut chip thickness, which reduces the real rake angle to negative, can reduce the normal stress on the tool flank face and lead to a decrease in the tool flank wear rate.
6
Afolalu, S. A., A. A. Abioye, J. O. Dirisu, I. P. Okokpujie, O. O. Ajayi, and O. R. Adetunji. "Investigation of wear land and rate of locally made HSS cutting tool." In 2018 6TH INTERNATIONAL CONFERENCE ON NANO AND MATERIALS SCIENCE: ICNMS 2018. Author(s), 2018. http://dx.doi.org/10.1063/1.5034332.
Full text
7
Das, Ranjan, Suhas S. Joshi, and Harish C. Barshilia. "Analytical Model of Progression of Flank Wear Land Width in Drilling." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-68134.
Full textAbstract:
In multi-point operations like drilling, cutting velocities and cutting edge geometries vary along cutting lips so is the rate of progression of flank wear. Analytical evaluation of flank wear land width in the case of complex tools has received a limited attention so far. This work evaluates progression of flank wear in orthogonal machining and adopts it to drilling. An abrasive flank wear has been modeled, wherein, cutting speed determines the rate of abrasion, and the feed rate determines the chip load. The model considers stress distribution along rake surfaces, and temperature dependent properties of tool and work materials. Assuming that the flank wear follows a typical wear progression as in a pin-on-disc test, the model evaluates cutting forces and the consequent abrasive wear rate for an orthogonal cutting. To adopt it to drilling, variation in cutting velocity and, dynamic variation in rake, shear and friction angles along the length of the cutting lips have been considered. Knowing the wear rate, the length of the worn out flank (VB) has been evaluated. The model captures progression of flank wear in zones I, II and III of a typical tool life plot. It marginally underestimates the wear in the rapid wear region and marginally overestimates it in the steady-state region.
8
Dlamini, Niniza S. P., Iakovos Sigalas, and Andreas Koursaris. "Cutting Tool Wear and Mechanisms of Chip Formation During High-Speed Machining of Compacted Graphite Iron." In ASME/STLE 2007 International Joint Tribology Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ijtc2007-44026.
Full textAbstract:
Cutting tool wear of polycrystalline cubic boron nitride (PcBN) tools was investigated in oblique turning experiments when machining compacted graphite iron at high cutting speeds, with the intention of elucidating the failure mechanisms of the cutting tools and presenting an analysis of the chip formation process. Dry finish turning experiments were conducted in a CNC lathe at cutting speeds in the range of 500–800m/min, at a feed rate of 0.05mm/rev and depth of cut of 0.2mm. Two different tool end-of-life criteria were used: a maximum flank wear scar size of 0.3mm (flank wear failure criterion) or loss of cutting edge due to rapid crater wear to a point where the cutting tool cannot machine with an acceptable surface finish (surface finish criterion). At high cutting speeds, the cutting tools failed prior to reaching the flank wear failure criterion due to rapid crater wear on the rake face of the cutting tools. Chip analysis, using SEM, revealed shear localized chips, with adiabatic shear bands produced in the primary and secondary shear zones.
9
Prabha, Rajesh, and J. Edwin Raja Dhas. "Fuzzy logic — A decision making tool for wear rate prediction in aluminum composite." In 2017 First International Conference on Recent Advances in Aerospace Engineering (ICRAAE). IEEE, 2017. http://dx.doi.org/10.1109/icraae.2017.8297230.
Full text
10
Guo, Kai, Bin Yang, Jie Sun, and Vinothkumar Sivalingam. "Investigation on the Tool Wear Model and Equivalent Tool Life in End Milling Titanium Alloy Ti6Al4V." In ASME 2018 13th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/msec2018-6505.
Full textAbstract:
Titanium alloys are widely utilized in aerospace thanks to their excellent combination of high-specific strength, fracture, corrosion resistance characteristics, etc. However, titanium alloys are difficult-to-machine materials. Tool wear is thus of great importance to understand and quantitatively predict tool life. In this study, the wear of coated carbide tool in milling Ti-6Al-4V alloy was assessed by characterization of the worn tool cutting edge. Furthermore, a tool wear model for end milling cutter is established with considering the joint effect of cutting speed and feed rate for characterizing tool wear process and predicting tool wear. Based on the proposed tool wear model equivalent tool life is put forward to evaluate cutting tool life under different cutting conditions. The modelling process of tool wear is given and discussed according to the specific conditions. Experimental work and validation are performed for coated carbide tool milling Ti-6Al-4V alloy.
Reports on the topic "Tool wear rate"
1
Diop, Ahmed. Country Diagnostic Study – Senegal. Islamic Development Bank Institute, 2021. http://dx.doi.org/10.55780/rp21003.
Full textAbstract:
The Country Diagnostic Study (CDS) for Senegal uses the Hausmann-Rodrik-Velasco growth diagnostics model to identify the binding constraints being faced in its quest for higher and more sustained economic growth and make recommendations to relax these constraints. Hence, the findings of the CDS can help the Islamic Development Bank in identifying areas where it can have a greater impact and provide an evidence-basis to support the development of the Member Country Partnership Strategy. After decades of subdued and highly volatile economic growth due to heavy dependence on primary commodities and low productivity, Senegal experienced an unprecedented growth acceleration from 2014 to 2019. However, there appeared to be a weak correlation between economic growth and jobs creation. In addition, about 90 percent of non-agricultural employment is estimated to be informal. The national poverty rate decreased by 5 percentage points between 2011 and 2018. Nonetheless, the absolute number of poor people has increased. Furthermore, regional disparities are persistent. Despite the country’s solid performance in the field of governance, further simplification and transparency of business procedures and regulations will be critical in addressing the challenge of informality. Efforts to address informality in the economy should also target the issue of access to finance through the design of financing mechanisms based on specific needs assessment and risk management tools. Senegal will also need to create the conditions for higher competitiveness and follow upgrading trajectories in global and regional value chains. In this respect, both physical and digital connectivity will be essential.
2
Butterweck, Gernot, Alberto Stabilini, Benno Bucher, et al. Aeroradiometric measurements in the framework of the swiss exercise ARM23. Paul Scherrer Institute, PSI, 2024. http://dx.doi.org/10.55402/psi:60054.
Full textAbstract:
The flights of the civil (ARM23c) and military (ARM23m) parts of the exercise were performedbetween June 19th and 23rd and between September 11th and September 15th,respectively. The measuring system RLL001 was employed for all measurements. As usual, during the civil exercise the environs of some of the Swiss nuclear power plants were screened, on behalf of the Swiss Nuclear Safety Inspectorate (ENSI). At the site of the nuclear power plant Gösgen (KKG) with its pressurized water reactor, the activation products of the primary coolant loop are kept in the well shielded reactor building, thus generating no elevated readings neither on the premises nor in the vicinity of the power plant. The nuclear power plant of Mühleberg (KKM) is now being decommissioned. During this phase, activated components are temporarily stored and processed on the plant premises. The dose rate produced by these components, easily detected and identified with the Swiss airborne gamma spectrometry system, is nevertheless very modest and closely monitored by the Swiss Nuclear Safety Inspectorate (ENSI). Search exercises for radionuclide sources were performed in both parts of ARM23. The operational software of the RLL systems was able to detect the radionuclide sources placed in military training areas. The Man-Made Gross-Count (MMGC) ratio demonstrated a good sensitivity for the identification of radionuclide sources. Nevertheless, a weak radionuclide source placed in the field of view of the helicopter (300 m x 300 m at a ground clearance of 100 m) together with a much stronger radionuclide source emitting higher energy photons was obscured due to Compton scattered photons and therefore could not be detected. Measurements of two teams using drones equipped with radiation monitors demonstrated that low flying drones (ground clearance below 10 m) can be a valuable and complementary tool to identify sources and to further reduce the target area to be searched with ground teams. An altitude profile over Lake Constance confirmed the already observed influence of airborne radon progeny on the determination of cosmic and background corrections. Background flights were performed over several Swiss regions. Besides attenuation effects of water bodies, variations of natural radionuclide content could be observed. A new flight strategy in alpine topography was tested near the Swiss mountain Chrüz. Following contour lines of the topography reduces the necessity for drastic flight altitude changes compared to the parallel line pattern normally used, but is much more challenging for the pilots.
3
Baumgartner, Franz, Cyril Allenspach, Ebrar Özkalay, et al. Performance of Partially Shaded PV Generators Operated by Optimized Power Electronics 2024. Edited by Ulrike Jahn. International Energy Agency Photovoltaic Power Systems Programme, 2024. https://doi.org/10.69766/leof5152.
Full textAbstract:
Inhomogeneous shading on the PV generator leads to disproportionately high losses. As the potential of PV generation on roofs or façades is to be increasingly utilised in the coming decades, these cases will occur more frequently. The aim here is to provide an overview of the challenges and state-of-the-art technical solutions for partial shading. Current developments in PV engineering show that maximum performance lies in the combination between optimised module placement, the use of modules that are tolerant of shading and optimised power electronics. Shortly after the discovery of the solar cell, blocking or bypass diodes were used to solve the inhomogeneous currents of groups of solar cells arranged in series or parallel wiring. Even today, they are still the most efficient and robust solution for the majority of common shading PV applications. Due to the very high rated outputs of the solar modules and the presence of only three bypass diodes, high temperatures can occur on a locally shaded solar cell. This forces heat outputs of up to 200W or 100W in the butterfly module connection through the associated activated bypass diode, which must be dissipated by the most shaded cell. If additional small-area defects occur in this affected solar cell, hotspot peak temperatures can occur, which can lead to permanent damage to the module or the risk of fire. However, in order to prevent a third of the module output being lost in this case, four or more bypass diodes are now used in so-called shadow-tolerant PV modules. With a higher number of bypass diodes per module area, it is also possible to selectively bypass smaller, less efficient areas of the module, which leads to an increase in the module yield. The hotspot effects can also be comprehensively and robustly prevented by the small number of solar cells per bypass diode, provided the bypass diode is properly designed. The first manufacturers are beginning to place these shade-tolerant PV modules on the markets. Today, planners can also select different power electronics systems for the next step in system integration towards grid feed-in, i.e. the connection of the individual modules in the string. This is the classic series connection of all modules in the string to the input of the DC/AC string inverter (SINV), which leads to the highest yields for weak and medium shading. This applies, for example, to light shading with a chimney or a ventilation pipe, where no more than one tenth of the modules in the string are reached by the shade at the same time during the six hours around midday, even when using standard modules with only three bypass diodes. (see Table 1) With medium to heavy shading, the widely used DC/DC converters directly on the PV module (MLPE), often also called power optimisers, can be used profitably. However, the combination of shade-tolerant PV modules with conventional SINVs can often deliver comparable annual yields. However, if the optimisers are also used behind each module even with weak shading (allMLPE), they deliver less yield in total than the simple SINV, as their own DC/DC losses then have a negative impact compared to simple connectors. This only becomes apparent if the MLPE manufacturers' data sheet claims of 99% efficiency are not viable. The published measurements carried out in independent laboratories over the last four years are listed in this report, which suggest that losses are around 2% higher. As the differences in yield between the power electronics variants SINV and MLPE are usually less than four per cent in annual yield for light to medium shading, the above-mentioned real MLPE efficiency at the specific operating points plays the decisive role in planning the most efficient system. However, as the commercial PV software planning tools currently use these MLPE manufacturer specifications which are over estimated, no meaningful system comparison can be expected for these shading categories. In this report the results of annual simulations performed by some sophisticated simulation tools that take these real MLPE losses into account are discussed.
4
Lehotay, Steven J., and Aviv Amirav. Fast, practical, and effective approach for the analysis of hazardous chemicals in the food supply. United States Department of Agriculture, 2007. http://dx.doi.org/10.32747/2007.7695587.bard.
Full textAbstract:
Background to the topic: For food safety and security reasons, hundreds of pesticides, veterinary drugs, and environmental pollutants should be monitored in the food supply, but current methods are too time-consuming, laborious, and expensive. As a result, only a tiny fraction of the food is tested for a limited number of contaminants. Original proposal objectives: Our main original goal was to develop fast, practical, and effective new approaches for the analysis of hazardous chemicals in the food supply. We proposed to extend the QuEChERS approach to more pesticides, veterinary drugs and pollutants, further develop GC-MS and LC-MS with SMB and combine QuEChERS with GC-SMB-MS and LC-SMB-EI-MS to provide the “ultimate” approach for the analysis of hazardous chemicals in food. Major conclusions, solutions and achievements: The original QuEChERS method was validated for more than 200 pesticide residues in a variety of food crops. For the few basic pesticides for which the method gave lower recoveries, an extensive solvent suitability study was conducted, and a buffering modification was made to improve results for difficult analytes. Furthermore, evaluation of the QuEChERS approach for fatty matrices, including olives and its oil, was performed. The QuEChERS concept was also extended to acrylamide analysis in foods. Other advanced techniques to improve speed, ease, and effectiveness of chemical residue analysis were also successfully developed and/or evaluated, which include: a simple and inexpensive solvent-in-silicone-tube extraction approach for highly sensitive detection of nonpolar pesticides in GC; ruggedness testing of low-pressure GC-MS for 3-fold faster separations; optimization and extensive evaluation of analyte protectants in GC-MS; and use of prototypical commercial automated direct sample introduction devices for GC-MS. GC-MS with SMB was further developed and combined with the Varian 1200 GCMS/ MS system, resulting in a new type of GC-MS with advanced capabilities. Careful attention was given to the subject of GC-MS sensitivity and its LOD for difficult to analyze samples such as thermally labile pesticides or those with weak or no molecular ions, and record low LOD were demonstrated and discussed. The new approach of electron ionization LC-MS with SMB was developed, its key components of sample vaporization nozzle and flythrough ion source were improved and was evaluated with a range of samples, including carbamate pesticides. A new method and software based on IAA were developed and tested on a range of pesticides in agricultural matrices. This IAA method and software in combination with GC-MS and SMB provide extremely high confidence in sample identification. A new type of comprehensive GCxGC (based on flow modulation) was uniquely combined with GC-MS with SMB, and we demonstrated improved pesticide separation and identification in complex agricultural matrices using this novel approach. An improved device for aroma sample collection and introduction (SnifProbe) was further developed and favorably compared with SPME for coffee aroma sampling. Implications, both scientific and agricultural: We succeeded in achieving significant improvements in the analysis of hazardous chemicals in the food supply, from easy sample preparation approaches, through sample analysis by advanced new types of GC-MS and LCMS techniques, all the way to improved data analysis by lowering LOD and providing greater confidence in chemical identification. As a result, the combination of the QuEChERS approach, new and superior instrumentation, and the novel monitoring methods that were developed will enable vastly reduced time and cost of analysis, increased analytical scope, and a higher monitoring rate. This provides better enforcement, an added impetus for farmers to use good agricultural practices, improved food safety and security, increased trade, and greater consumer confidence in the food supply.
5
Tabakovic, Momir, Stefan Savic, Andreas Türk, et al. Analysis of the Technological Innovation System for BIPV in Austria. Edited by Michiel Van Noord. International Energy Agency Photovoltaic Power Systems Programme, 2024. http://dx.doi.org/10.69766/aocp4683.
Full textAbstract:
This report analyses the Technological Innovation System (TIS) of Building Integrated Photovoltaics (BIPV) in Austria. The study’s scope is consistent with the IEA PVPS Task 15 report [1].The analysis aims to facilitate and support the innovation, development, and implementation of industrial solutions of BIPV technologies. In Austria, the use of BIPV is still a niche application and covers under 2% of all implemented PV systems [1]. BIPV technology in Austria has historically developed with the support of different public financial incentives, national and European. The history of BIPV is somehow tightened to the history of PV. The first BIPV prototypes were developed by PV companies in the framework of national or European research activities, with the first development and innovation projects starting around 2003. In general, it should be mentioned that in the last years, PV and BIPV companies have increased specialization in the production of BIPV, especially colored and semitransparent PV modules. In this regard, a wide range of variants are offered (printing, coating, films). The colored components are mainly purchased from glass companies or polymer film producers. Another trend in Austria is the production of transparent glass/glass modules for integration in facades, skylights, winter gardens, or courtyard roofing. In 2020, the government of Austria presented a program called EAG (Erneuerabre Ausbau Gesetz) or Renewable Expansion Act [3.3.1 Hard institutions]containing certain working points to be implemented by 2024. Some of the measures are directly or indirectly relevant to the BIPV development and installation. Such as the PV encapsulation films using interference pigment technology from Lenzing Plastics. This TIS assessed the BIPV market through eight functional areas and provided the following results: ⁃ The analysis of knowledge development showed that it can be classified as moderate. On the one hand, there are not enough training and further education opportunities in the field of BIPV available, but on the other hand, the PV manufacturers and research institutions are driving forward the development of knowledge in the field of BIPV. ⁃ Knowledge dissemination is well advanced internationally within the research community but insufficient at the practical, national level, particularly between the PV industry and the construction sector. Architects are demanding more information from PV manufacturers and suppliers, who share their information only irregularly with the architectural community. Usually, architects obtain this information from PV technology platforms through workshops, brochures, and projects. However, architects have to engage with it more extensively. The goal is to make BIPV more appealing to architects. Thus, we have to summarize that knowledge dissemination is inadequate/weak. ⁃ Entrepreneurial willingness to experiment can be classified as moderate. Overall, it can be said that there are four players in the Austrian BIPV market and a substantial number of newcomers and small innovative players who could take the role of innovation drivers. However, there are too few opportunities for highly specialized small companies. ⁃ Resource mobilization is well positioned financially and in terms of network services. However, and this is essential if we want to expand the BIPV market strongly, there is a lack of skilled personnel (human resources) to carry out the expansion, which is why this function is rated to only be moderate. ⁃ The scoring of social capital is weak. The connection where there is a lack of communication is between the (BI)PV planner and the architects. In most projects, the (BI)PV planner is not involved in the early stages of the building design process. In addition, conventional PV planners have no experience or are hesitant of planning BIPV systems. ⁃ The legitimacy is moderate, but as the acceptance of PV improves from year to year, the chance of better acceptance of PV integrated into the building, i.e., BIPV, also increases. However, there are still reservations and resistance towards individual, specific BIPV projects. This resistance could be reduced by increasing knowledge about the multifunctional possibilities of BIPV at the decision-maker and customer stage as well as by showing best practice examples - Guidance of the search is moderate, as there are no specific political targets for BIPV, but there are for PV. However, the government and relevant authorities aim to implement clean energy development positively and apply applicable policies and regulations. There is an increased subsidy for innovative PV solutions [2] which also includes BIPV. ⁃ It can be stated that the market formation of BIPV in Austria still offers room for improvement. When it comes to governmental-driven incentives and support for the BIPVmarket development, the missing technical standards (e.g., fire safety regulations) and the absence of regulatory obligations on renewable energies in the local building codes are the biggest weaknesses. The structural and functional analysis is followed by a coupled structural-functional analysis. This assessment will help identify weaknesses and strengths and recommend strategies that will enable the growth of BIPV from a niche market to a major market segment. The aim is for photovoltaics (PV) on buildings to be primarily designed as Building Integrated Photovoltaics (BIPV) to reduce additional costs. This, combined with the avoided costs for other components of the building, should result in cost parity with Building-Applied Photovoltaics (BAPV). It is also crucial to encourage all manufacturers of building envelope components to ensure that their products offer the dual benefit of serving as building components while also generating electricity. By doing so, such products can become standard in the industry. The transition from BAPV to BIPV was already analyzed in a 2015 BIPV brochure [2] from the Austrian Photovoltaics Technology Platform (TPPV), which discussed the advantages of an integrated solution versus an attached solution and outlined the necessary steps to make BIPV the standard for building PV. The recommendations are summarized as follows: i) It is important to involve (BI)PV in the early stages of the building planning process. ii) successful implementation projects must be made public through various channels to increase knowledge about BIPV technology and its possibilities (e.g., lighthouse projects in public buildings). iii) PV standards and construction codes have to be harmonized. iv) The Austrian government should stipulate the use of PV in the obligatory building specifications. v) Another recommendation would be to enact a law requiring every sealed area to be checked for dual use with (BI)PV. One positive development worth mentioning is the Climate Fund's Lighthouse call, which focuses specifically on integrated PV and offers higher grants for BIPV than the Renewable Expansion Act] , demonstrating increased interest and commitment to this technology. In addition, the TPPV Innovation Awards, which were awarded for the first time specifically for building-integrated PV and now include other topics of PV integration outside of buildings, are a sign that the industry is broadening its perspective and recognizing the importance of BIPV beyond traditional applications. These developments could help to further promote the acceptance and deployment of BIPV and drive innovation in this area. Nevertheless, it is important to consider the significantly higher costs of BIPV products, as well as the greatly increased planning effort that arises when PV becomes an integral building product.
6
Börjesson, Patrik, Maria Eggertsen, Lachlan Fetterplace, et al. Long-term effects of no-take zones in Swedish waters. Edited by Ulf Bergström, Charlotte Berkström, and Mattias Sköld. Department of Aquatic Resources, Swedish University of Agricultural Sciences, 2023. http://dx.doi.org/10.54612/a.10da2mgf51.
Full textAbstract:
Marine protected areas (MPAs) are increasingly established worldwide to protect and restore degraded ecosystems. However, the level of protection varies among MPAs and has been found to affect the outcome of the closure. In no-take zones (NTZs), no fishing or extraction of marine organisms is allowed. The EU Commission recently committed to protect 30% of European waters by 2030 through the updated Biodiversity Strategy. Importantly, one third of these 30% should be of strict protection. Exactly what is meant by strict protection is not entirely clear, but fishing would likely have to be fully or largely prohibited in these areas. This new target for strictly protected areas highlights the need to evaluate the ecological effects of NTZs, particularly in regions like northern Europe where such evaluations are scarce. The Swedish NTZs made up approximately two thirds of the total areal extent of NTZs in Europe a decade ago. Given that these areas have been closed for at least 10 years and can provide insights into long-term effects of NTZs on fish and ecosystems, they are of broad interest in light of the new 10% strict protection by 2030 commitment by EU member states. In total, eight NTZs in Swedish coastal and offshore waters were evaluated in the current report, with respect to primarily the responses of focal species for the conservation measure, but in some of the areas also ecosystem responses. Five of the NTZs were established in 2009-2011, as part of a government commission, while the other three had been established earlier. The results of the evaluations are presented in a synthesis and also in separate, more detailed chapters for each of the eight NTZs. Overall, the results suggest that NTZs can increase abundances and biomasses of fish and decapod crustaceans, given that the closed areas are strategically placed and of an appropriate size in relation to the life cycle of the focal species. A meta-regression of the effects on focal species of the NTZs showed that CPUE was on average 2.6 times higher after three years of protection, and 3.8 times higher than in the fished reference areas after six years of protection. The proportion of old and large individuals increased in most NTZs, and thereby also the reproductive potential of populations. The increase in abundance of large predatory fish also likely contributed to restoring ecosystem functions, such as top-down control. These effects appeared after a 5-year period and in many cases remained and continued to increase in the longer term (>10 years). In the two areas where cod was the focal species of the NTZs, positive responses were weak, likely as an effect of long-term past, and in the Kattegat still present, recruitment overfishing. In the Baltic Sea, predation by grey seal and cormorant was in some cases so high that it likely counteracted the positive effects of removing fisheries and led to stock declines in the NTZs. In most cases, the introduction of the NTZs has likely decreased the total fishing effort rather than displacing it to adjacent areas. In the Kattegat NTZ, however, the purpose was explicitly to displace an unselective coastal mixed bottom-trawl fishery targeting Norway lobster and flatfish to areas where the bycatches of mature cod were smaller. In two areas that were reopened to fishing after 5 years, the positive effects of the NTZs on fish stocks eroded quickly to pre-closure levels despite that the areas remained closed during the spawning period, highlighting that permanent closures may be necessary to maintain positive effects. We conclude from the Swedish case studies that NTZs may well function as a complement to other fisheries management measures, such as catch, effort and gear regulations. The experiences from the current evaluation show that NTZs can be an important tool for fisheries management especially for local coastal fish populations and areas with mixed fisheries, as well as in cases where there is a need to counteract adverse ecosystem effects of fishing. NTZs are also needed as reference for marine environmental management, and for understanding the effects of fishing on fish populations and other ecosystem components in relation to other pressures. MPAs where the protection of both fish and their habitats is combined may be an important instrument for ecosystembased management, where the recovery of large predatory fish may lead to a restoration of important ecosystem functions and contribute to improving decayed habitats. With the new Biodiversity Strategy, EUs level of ambition for marine conservation increases significantly, with the goal of 30% of coastal and marine waters protected by 2030, and, importantly, one third of these areas being strictly protected. From a conservation perspective, rare, sensitive and/or charismatic species or habitats are often in focus when designating MPAs, and displacement of fisheries is then considered an unwanted side effect. However, if the establishment of strictly protected areas also aims to rebuild fish stocks, these MPAs should be placed in heavily fished areas and designed to protect depleted populations by accounting for their home ranges to generate positive outcomes. Thus, extensive displacement of fisheries is required to reach benefits for depleted populations, and need to be accounted for e.g. by specific regulations outside the strictly protected areas. These new extensive EU goals for MPA establishment pose a challenge for management, but at the same time offer an opportunity to bridge the current gap between conservation and fisheries management.
7
The Experience of Latin America and the Caribbean in Urbanization: Knowledge Sharing Forum on Development Experiences: Comparative Experiences of Korea and Latin America and the Caribbean. Inter-American Development Bank, 2015. http://dx.doi.org/10.18235/0007004.
Full textAbstract:
The developing region that has experienced one of the greatest urban growth in the world is Latin America and the Caribbean (LAC). More than 80% of its population currently lives in cities and this figure is projected to reach 90% in 25 years. As part of this process, we can identify different urbanization trends across the region: slow growth rates of megacities due to lower levels of rural-urban migration and greater intra-city migration; high growth rates of mid-size cities; and urban footprints growing faster than populations. Therefore, this more contained growth in larger cities, the existence of a 'demographic bonus'in the next 30 years, and new poles of development in secondary cities offer new opportunities to grow in a more sustainable and equitable way while addressing existing challenges in cities. Rapid urban growth in the countries of LAC has posed a series of challenges that cities, especially intermediate cities, must address to ensure their sustainability in the coming years. Those challenges include limited mobility, poor urban planning, pollution, increased vulnerability to natural hazards, inequity, lack of compliance with labor and building regulations, unemployment, crime, and weak institutional and fiscal capacity, among others. These conditions undermine cities' sustainability and reduce the quality of life of their inhabitants. Given this context, the Bank has developed the Emerging and Sustainable Cities Initiative (ESCI) as a particular approach to help mid-size cities understand their challenges and address them in a more integrated way based upon a model of efficiency in planning and the use of resources that prioritizes sustainability and a higher quality of life for all citizens. The ESCI's action-oriented methodology prioritizes projects in critical areas for sustainability, promoting a better quality of life by strengthening planning, incorporating climate change features, and ensuring citizenship engagement. From the ESCI's experience in more than 20 cities in LAC, important lessons have been learned: introducing adaptation and mitigation measures is an opportunity to address environmental issues and limit the impact of climate change; urban economic development should be based on dense, compact, efficient cities, with mixed land use, and concrete actions to generate productive employment; planning should be considered a basic tool for sustainable urban development and growth; and finally, fiscal capacity should be strengthened with greater access to financial resources and connectivity. Cities that cannot provide an adequate quality of live and preserve physical and environmental assets for future generations will not be competitive. These cities will have a tough time attracting investments and generating productive jobs. As a result of ESCI's learning process, we have realized that it is necessary to examine in a more direct and detailed manner the competitiveness of a city proposing concrete actions to increase investments and to generate productive employment. Involving civil society in city planning and engaging the private sector in urban infrastructure services are also key ingredients of a competitive and successful city. As part of the Bank's knowledge dissemination series, this document exhibits the Latin American and Caribbean experience in terms of urbanization, the identification of the challenges posed by this trend, the IDB's approach to promote the sustainability of LAC mid-size urban centers, the lessons learned from how those challenges are being solved, and their impact on medium-term sustainability of cities and their quality of life.