Letteratura scientifica selezionata sul tema "Solution Process MoO3"
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Articoli di riviste sul tema "Solution Process MoO3"
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Wu, Jianfeng, Zhichao Chen, Xiaohong Xu, Peng Wei, Guobin Xie e Xinyi Zhang. "The Growth Process and Photocatalytic Properties of h-MoO3 and α-MoO3 under Different Conditions". Crystals 13, n. 4 (1 aprile 2023): 603. http://dx.doi.org/10.3390/cryst13040603.
Testo completoAbstract (sommario):
In this experiment, we investigated the effects of different reactions on the growth process and morphology of h-MoO3 and α-MoO3, and their optical properties and photocatalytic activities were also investigated. Orthogonal experiments were designed to investigate the effects of four influencing factors, namely the amount of ammonium molybdate tetrahydrate (AHM), the type of acid, the reaction temperature and the holding time, on the morphology of h-MoO3 by a microwave hydrothermal method. The phase and morphology were analyzed by using advanced physicochemical techniques. The XRD results showed that the samples produced by the microwave hydrothermal method had sharp diffraction peaks, high crystallinity and complete crystalline shape. AHM generates h-MoO3 in both hydrochloric and nitric acid environments. In particular, when the temperature rises to 200 °C, the generated h-MoO3 will be converted to α-MoO3 in a nitric acid environment, which will be generated in a sulfuric acid environment. Therefore, increasing the reaction temperature will result in the conversion of h-MoO3 to α-MoO3 in sulfuric acid solution. SEM results show that the sample prepared from hydrochloric acid solution has a complete hexagonal prism morphology, while the sample prepared from sulfuric acid solution presents a long fibrous morphology, and the sample prepared from nitric acid solution has many defects on the surface of the hexagonal prism morphology. Interestingly, sample A11 prepared in nitric acid solution showed a spherical structure. Since the generated A3, A6 and A9 samples are all stable phase α-MoO3, they have a wider band gap compared with other samples. Their particle size is up to the nanometer scale, so they have strong adsorption properties. The spherical sample A11 has excellent adsorption and photocatalytic activity.
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Maniruzzaman, Md, Rahim Abdur, Md Abdul Kuddus Sheikh, Son Singh e Jaegab Lee. "Conductive MoO3–PEDOT:PSS Composite Layer in MoO3/Au/MoO3–PEDOT:PSS Multilayer Electrode in ITO-Free Organic Solar Cells". Processes 11, n. 2 (16 febbraio 2023): 594. http://dx.doi.org/10.3390/pr11020594.
Testo completoAbstract (sommario):
The solution-processed and conductive MoO3–PEDOT:PSS (Mo–PPSS) composite layer in a MoO3/Au/MoO3–PEDOT:PSS (MoAu/Mo–PPSS) multilayer electrode in ITO-free organic solar cells (OSCs) was optimized in terms of electrical conductivity, interfacial contact quality, work function, and process wettability of the conductive composite thin film. The surface composition of the PEDOT:PSS film onto different electrodes was observed by using X-Ray Photoelectron Spectroscopy. The PEDOT:PSS-MoO3 composite protects the dissolution of individual MoO3 with PEDOT:PSS, which was confirmed by Auger Electron Spectroscopy. The UV-Visible spectroscopy showed that the photoactive layer of P3HT:PCBM absorbs in the wavelength range of 300–650 nm with the maximum absorption at 515 nm (2.40 eV). The device performance of 3.97% based on an MoAu/Mo–PPSS conductive composite electrode exhibited comparable enhancement and only 6% enhancement compared to an ITO-based electrode (3.91%). The enhancement of device efficiency was mainly due to relatively higher conductivity, a low work function of the conductive metal oxide-metal-metal oxide/polymer composite, and an enhancement of interfacial contact quality between the hole transport layer (HTL) and the mixed organic polymeric photoactive layer. These results indicate that the solution-processable Mo–PPSS conductive composite layer of the MoO3/Au multilayer electrode can replace the ITO-based electrode in the bulk of heterojunction organic photovoltaics (OPVs).
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BAI, SHOULI, SONG CHEN, YUAN TIAN, RUIXIAN LUO, DIANQING LI e AIFAN CHEN. "HYDROTHERMAL SYNTHESIS OF α-MoO3 NANORODS FOR NO2 DETECTION". International Journal of Nanoscience 11, n. 06 (dicembre 2012): 1240044. http://dx.doi.org/10.1142/s0219581x12400443.
Testo completoAbstract (sommario):
Thermodynamically stable molybdenum trioxide nanorods have been successfully synthesized by a simple hydrothermal process. The product exhibits high-quality, single-crystalline layered orthorhombic structure (α- MoO3 ), and aspect ratio over 20 by characterizations of X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and Fourier transform infrared (FT-IR). The growth mechanism of α- MoO3 nanorods can be understood by electroneutral and dehydration reaction, which is highly dependent on solution acidity and hydrothermal temperature. The sensing tests show that the sensor based on MoO3 nanorods exhibits high sensitivity to NO2 and is not interferred by CO and CH4 , which makes this kind sensor a competitive candidate for NO2 detection. The intrinsic sensing performance of MoO3 maybe arise from its nonstoichiometry of MoO3 owing to the presence of Mo5+ and oxygen vacancy in MoO3 lattice, which has been confirmed by X-ray photoelectron spectroscopy (XPS) analysis. The sensing mechanism of MoO3 for NO2 is also discussed.
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Zeng, Yi, Chaoping Liang, Yuanjun Sun, Na Wang, Xiangdong Ding e Jun Sun. "Effect of Mo Oxides on the Phase Composition and Characteristics of Mo-10Re Pre-Alloyed Powders Co-Reduced with NH4ReO4". Materials 16, n. 17 (30 agosto 2023): 5936. http://dx.doi.org/10.3390/ma16175936.
Testo completoAbstract (sommario):
Mo-Re pre-alloyed powders are crucial raw materials in fabricating Mo-Re alloys, and their properties can significantly impact the properties of the resulting alloys. The powders are usually produced by the co-reduction of a mixture of Mo and Re oxides. However, it remains unclear if the overall characteristics of the produced Mo-Re powders rely on the different combinations of the Mo and Re oxide precursors. Therefore, in this work, a comparative study is conducted on the co-reduction processes of different Mo oxides together with NH4ReO4, along with its influence on the size distribution and phase composition of the resulting Mo-10Re pre-alloyed powders. The results show that MoO3 is more promising than MoO2 as a precursor material. The powders fabricated using MoO3, when compared to MoO2, have a much more uniform size distribution, with a primary particle size ranging from 0.5–4 μm. In addition, it is also beneficial to achieve atomic-scale homogeneous mixing with Mo and Re elements and the formation of a solely Mo(Re) solid solution if MoO3 is used as a precursor oxide. In contrast, such desirable features were not identified when using the MoO2 route. The reason for this discrepancy may relate to whether Mo-O-Re metallurgical bonding has formed during the co-reduction process.
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Eliseeva, E. A., S. L. Berezina e I. G. Gorichev. "Kinetics of Molybdenum Trioxide Dissolution in the Alkaline Medium". Herald of the Bauman Moscow State Technical University. Series Natural Sciences, n. 2 (107) (aprile 2023): 98–109. http://dx.doi.org/10.18698/1812-3368-2023-2-98-109.
Testo completoAbstract (sommario):
The paper presents experimental study results of the MoO3 powder samples dissolution kinetics in the aqueous ammonia solution at various pH concentrations and values. Molybdenum ions concentration in the filtrate samples was determined spectrophotometrically. Kinetic characteristics were obtained, and kinetic parameters (specific dissolution rate, reaction order with respect to the H+ ion) were calculated. It was established that the dissolution rate was increasing in the ammonia solution concentration range of 0.02--1.26 mol/l, and with the growing pH it passed through the maximum. Taking into account the acid-base equilibria constants, the dissolution process was simulated, and its stage-by-stage nature was established. Fractional reaction order with respect to the H+ ions calculated from the curves plotted in the α--t/t0.5 coordinates (affine transformation method) indicated the adsorption mechanism of dissolution. It was shown that the MoO3 dissolution proceeded with formation of the intermediate adsorption complexes. Due to the HMoO4- low concentration in the MoO3 concentration within the studied pH range by the surface-active particle, on which groups of ions were adsorbed, the MoO4- could be considered. The results obtained are an addition to the data possessed on the molybdenum oxide phase and other transitional metals behavior. They could be applied in the practical applications associated with dissolving molybdenum in the alkaline electrolytes
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Du, Xiaoni, Xiaohong Wang, Yang Liu e Peizhong Feng. "Spray solution combustion synthesis of hollow porous MoO3 photocatalyst". Ceramics International 45, n. 9 (giugno 2019): 12599–601. http://dx.doi.org/10.1016/j.ceramint.2019.03.168.
Testo completo
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Dhanabal, Rengasamy, Dhanasekaran Naveena, Sivan Velmathi e Arumugam Chandra Bose. "Reduced Graphene Oxide Supported Molybdenum Oxide Hybrid Nanocomposites: High Performance Electrode Material for Supercapacitor and Photocatalytic Applications". Journal of Nanoscience and Nanotechnology 20, n. 7 (1 luglio 2020): 4035–46. http://dx.doi.org/10.1166/jnn.2020.17779.
Testo completoAbstract (sommario):
Using a simple solution based synthesis route, hexagonal MoO3 (h-MoO3) nanorods on reduced graphene oxide (RGO) sheets were prepared. The structure and morphology of resulting RGO-MoO3 nanocomposite were characterized using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). The optical property was studied using UV-Visible diffuse reflectance spectroscopy (UV-Vis DRS) and photoluminescence spectroscopy (PL). The RGO-MoO3 nanocomposites were used as an electrode for supercapacitor application and photocatalyst for photodegradation of methylene blue (MB) and rhodamine B (RhB) under visible light irradiation. We demonstrated that the RGO-MoO3 electrode is capable of delivering high specific capacitance of 134 F/g at current density of 1 A/g with outstanding cyclic stability for 2000 cycles. The RGOMoO3 photocatalyst degrades 95% of MB dye within 90 min, and a considerable recyclability up to 4 cycles was observed. The quenching effect of scavengers test confirms holes are main reactive species in the photocatalytic degradation of MB. Further, the charge transfer process between RGO and MoO3 was schematically demonstrated.
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Ioakeimidis, Apostolos, Alina Hauser, Michael Rossier, Flavio Linardi e Stelios A. Choulis. "High-performance non-fullerene acceptor inverted organic photovoltaics incorporating solution processed doped metal oxide hole selective contact". Applied Physics Letters 120, n. 23 (6 giugno 2022): 233301. http://dx.doi.org/10.1063/5.0091671.
Testo completoAbstract (sommario):
Inverted organic photovoltaics (OPVs) allow flexibility on designing a roll-to-roll production process of OPVs, providing technological opportunities. The OPV roll-to-roll production process demands thick and high-performance solution-based hole selective contacts. Here, we show that a solution processed antimony-doped tin oxide (ATO) hole selective contact produced by spray pyrolysis route exhibits exceptional optoelectronic properties and functionality within non-fullerene acceptor PM6:Y6:PC70BM inverted OPVs. The corresponding solution processed inverted OPVs provide high power conversion efficiency values when a thick hole selective contact of solution processed doped ATO is incorporated within the inverted OPV device structure and similar light stability to that achieved with the commonly used thermally evaporated MoO3 hole selective contact.
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Nagar, Mangey Ram, Rohit Ashok Kumar Yadav, Deepak Kumar Dubey e Jwo-Huei Jou. "Solution Process Feasible Highly Efficient Organic Light Emitting Diode with Hybrid Metal Oxide Based Hole Injection/Transport Layer". MRS Advances 4, n. 31-32 (2019): 1801–9. http://dx.doi.org/10.1557/adv.2019.300.
Testo completoAbstract (sommario):
ABSTRACTOrganic light emitting diodes (OLEDs) have drawn great attention owing to their potential applications in high-quality flat display panels and smart solid-state lighting. Over the last three decades, numerous approaches have been made on material design and device physics to achieve high-efficiency and long-lifespan. Herein, we report a novel tactic to employ solution-processed hybrid metal oxide, molybdenum trioxide-tungsten trioxide (MoO3:WO3), as an efficient and stable hole injection/transport (HIL/HTL) and electron blocking layer for efficient OLEDs. By using phosphorescent orange-red emitter tris(2-phenylquinoline)-iridium(III) Ir(2-phq)3, MoO3:WO3 HIL based OLED device exhibits a power efficiency of 27.7 lm W-1 and 22.9 lm W-1 at 100 and 1000 cd m-2, respectively, which are 89% and 157% higher than that of conventional OLED device consisting of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) as an HIL. Moreover, the resulted device also displays 1.6 times lower turn-on voltage and 3.0 time higher brightness as compare to other counter part. The higher device performances of OLED device may be attributed to robust hole transporting ability, balanced charge carrier in the recombination zone and non-acidic nature of designed HIL. Our results demonstrate that a novel alternative approach based on transition metal oxide hybrid HIL/HTL as a substitute to PEDOT:PSS for high-efficiency solution process OLEDs.
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Pacco, Antoine, Teppei Nakano, Shota Iwahata, Akihisa Iwasaki e Efrain Altamirano Sanchez. "Etching of molybdenum via a combination of low-temperature ozone oxidation and wet-chemical oxide dissolution". Journal of Vacuum Science & Technology A 41, n. 3 (maggio 2023): 032601. http://dx.doi.org/10.1116/6.0002404.
Testo completoAbstract (sommario):
Etching of molybdenum was demonstrated in two steps. Mo was first oxidized in an ozone gas ambient to form molybdenum oxide. It is shown that comparable oxide thicknesses can be obtained in ozone and oxygen but at lower temperatures for the former. Initial oxide growth is fast but then considerably slows down due to its diffusion-limited character. The metal-oxide thickness can be controlled by temperature and defines the amount of metal etch per cycle (EPC). XPS analysis showed that the thermally grown oxide is MoO3. In the second, wet-chemical step, MoO3 was dissolved selectively toward the Mo metal using an aqueous solution. The dissolution rate of amorphous MoO3 formed in O3 at temperatures below ∼230 °C is fast, but the dissolution of MoO3 formed at Tox > 230 °C was shown to be incomplete. Cross-section TEM showed a matrix of amorphous oxide with crystallized MoO3 islands, the latter more difficult to dissolve. However, the crystalline phase could be completely and selectively removed using a more concentrated NH4OH solution at an elevated temperature (70 °C). The EPC was determined for temperatures between 150 and 290 °C. The etch rates increased with temperature from 1–2 nm/cycle at 150 °C to 5–6 nm/cycle at 290 °C. This hybrid thermal-wet etching sequence is well suited for vertical and lateral recess etching as it shows a controlled and isotropic dissolution of polycrystalline Mo at the nanoscale. Furthermore, the process shows a progressive surface smoothening upon increasing the number of etching cycles.
Tesi sul tema "Solution Process MoO3"
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Richet, Marina. "Cellules photovoltaïques organiques sur substrat flexible avec électrode supérieure transparente". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0035.
Testo completoAbstract (sommario):
Une cellule photovoltaïque organique est constituée d’une couche photoabsorbante comprise entre deux électrodes dont l’une au moins est transparente. Généralement, les cellules sont illuminées au travers de l’électrode inférieure transparente d’oxyde d’indium dopé à l’étain (ITO). Néanmoins, de nombreuses applications comme l’automobile nécessitant un éclairage par le dessus du module, nous nous sommes intéressés à l'élaboration de cellules photovoltaïques sur substrat flexible, avec l'électrode inférieure opaque et l'électrode transparente déposée sur le dessus de la cellule. Deux types d'architectures ont été développés. Dans le premier cas, la cellule solaire organique finale a été entièrement déposée par des techniques de dépôt en voie liquide avec les deux électrodes en PEDOT:PSS imprimées par jet d’encre. Dans le second cas, les cellules ont été élaborées sur électrode d'argent avec une électrode supérieure transparente tricouche oxyde/métal/oxyde (MoO3/Ag/MoO3) évaporée thermiquement. Les cellules solaires organiques réalisées selon la seconde architecture ont été connectées en série afin de créer un module photovoltaïque organique. Ce dernier a permis d’alimenter et de faire briller une LEDAn organic solar cell is made of a photoactive layer sandwiched between two electrodes among which one at least is transparent. Usually, solar cells are illuminated through the tin-doped indium oxide (ITO) bottom transparent electrode. Nevertheless, many applications like automobile requiring illumination from above the module, we designed photovoltaic cells on a flexible substrate, with an opaque bottom electrode and a top transparent one. Two types of architectures were developed. At first, the final organic solar cell was fully deposited by solution-process with both electrodes made of ink-jet printed PEDOT:PSS. Then the cells were elaborated on a silver bottom electrode with a transparent evaporated oxide/metal/oxide (MoO3/Ag/MoO3) top electrode. The organic solar cells made according to the second structure were connected in series to create an organic photovoltaic module. It allowed to power and shine a white LED
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PILLAI, SRIRAJ. "INTERFACE LAYER MODIFICATIONS USING POLYELECTROLYTES FOR HIGH EFFICIENCY ORGANIC SOLAR CELL". Thesis, 2015. http://dspace.dtu.ac.in:8080/jspui/handle/repository/14307.
Testo completoAbstract (sommario):
Considering the present world energy consumption and the exponential growth in human population, the growing energy need has to be mollified by the use of renewable sources of energy such as solar energy. Development is necessary but not at the cost of the future generations. The need of the hour is sustainable development. Thus, concerns about global warming and diminishing fossil fuel reserves have accelerated the search for low cost sources of renewable energy. Organic photovoltaics (OPVs) could be one such source. The investigation in this thesis takes a step in this direction.
The solar cells investigated in this thesis are BHJ solar cells. Fabrication of such cells involve etching of the substrates, preparation of the active material and buffer layer solutions, cleaning of the substrates, coating and deposition of the materials over the substrate. Finally once these solar cells are fabricated, J-V characterization of these cells are carried out to determine the device parameters- power conversion efficiency (PCE), open circuit voltage (VOC), fill factor (FF) and short circuit current density (JSC).
In this thesis we have focused on the interface layers in conventional and inverted organic solar cells. In case of conventional devices, we have tried to replace PEDOT:PSS by MoO3 layer and whereas in case of inverted devices, we have applied a polyelectrolyte based approach for modifying the ZnO interface layer.
Herein, we have used solution based approach for MoO3 and demonstrated that PEDOT:PSS can be successfully replaced by solution processed MoO3. For the modification of interface layer in case of inverted devices we have used the combination of zinc oxide and polyelectrolyte viz. ZnO-PDADMAC and ZnO-PSS nanocomposite. Both of these combinations have shown remarkable increase in the device parameters such as- JSC and η. However, the Zno-PDADMAC nanocomposite has shown a huge increase of ~ 22 times in device efficiency. These results have been discussed in detail in this thesis.Dr. SURESH CHAND Dr. J.P. TIWARI (Chief Scientist, NPL, Delhi) (Scientist, NPL, Delhi) Dr. PAWAN KUMAR TYAGI (Asst. Professor, DTU, Delhi) DEPARTMENT OF APPLIED PHYSICS DELHI TECHNOLOGICAL UNIVERSITY, BAWANA ROAD, DELHI-110042 JULY-2013
Libri sul tema "Solution Process MoO3"
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Siniawer, Eiko Maruko. Discarding Cultures. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190240400.003.0017.
Testo completoAbstract (sommario):
This chapter analyzes the Japanese social critique of overconsumption by way of addressing how the issue of food waste was linked to broader concerns, such as environmental degradation and the low rate of national food self-sufficiency. It describes how bureaucrats, citizens, corporations, and social critics are mobilized to dissuade the consuming public from their tastes for convenience and disposability. Using examples from didactic materials, such as the conservationist cartoons of High Moon and children's books, the chapter reveals national anxieties around food issues and the recourse to nostalgia as a solution for contemporary waste. Critics sought to imbue consumers with the spirit of earlier times, when consumers respected whole foods, produced through the sweat of farmers and prepared with motherly love, rather than relying on processed convenience foods.
Capitoli di libri sul tema "Solution Process MoO3"
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Barak, Miri, e Abeer Watted. "Project-Based MOOC". In Digital Tools and Solutions for Inquiry-Based STEM Learning, 282–307. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-2525-7.ch011.
Testo completoAbstract (sommario):
This chapter describes a project-based massive open online course (MOOC) in nanotechnology and nanosensors that was offered in two languages: English and Arabic. A mixed methods research was conducted to examine the role of project-based learning in the process of knowledge construction and motivation to learn a MOOC. The study compared between three groups of science and engineering students: English MOOCers, Arabic MOOCers, and university students. Findings indicated positive attitudes about learning in a project-based MOOC, especially with relation to gaining work experience. Findings also indicated that in a project-based setting, MOOC participants were mostly driven by a desire to establish connections with peers, whereas university students were mostly motivated by their interest in the subject matter. Arabic MOOCers, who were less successful in solving ill-defined problems, narrowed the gap, and at the end of the course received similar grades in the final project.
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Muñoz-Merino, Pedro J., José A. Ruipérez-Valiente, Juan Luis Sanz Moreno e Carlos Delgado Kloos. "Assessment Activities in Massive Open On-Line Courses". In Furthering Higher Education Possibilities through Massive Open Online Courses, 165–92. IGI Global, 2015. http://dx.doi.org/10.4018/978-1-4666-8279-5.ch008.
Testo completoAbstract (sommario):
This chapter analyzes the different implications of the new MOOC paradigm in assessment activities, emphasizing the differences with respect to other non MOOC educational technology environments and giving an insight about the redesign of assessment activities for MOOCs. The chapter also compares the different assessment activities that are available in some of the most used MOOC platforms at present. In addition, the process of design of MOOC assessment activities is analyzed. Specific examples are given about how to design and create different types of assessment activities. The Genghis authoring tool as a solution for the creation of some types of exercises in the Khan Academy platform is presented. Finally, there is an analysis of the learning analytics features related to assessment activities that are present in MOOCs. Moreover, some guidelines are provided about how to interpret and take advantage of this information.
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Muñoz-Merino, Pedro J., José A. Ruipérez-Valiente, Juan Luis Sanz Moreno e Carlos Delgado Kloos. "Assessment Activities in Massive Open On-Line Courses". In Learning and Performance Assessment, 611–38. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-0420-8.ch029.
Testo completoAbstract (sommario):
This chapter analyzes the different implications of the new MOOC paradigm in assessment activities, emphasizing the differences with respect to other non MOOC educational technology environments and giving an insight about the redesign of assessment activities for MOOCs. The chapter also compares the different assessment activities that are available in some of the most used MOOC platforms at present. In addition, the process of design of MOOC assessment activities is analyzed. Specific examples are given about how to design and create different types of assessment activities. The Genghis authoring tool as a solution for the creation of some types of exercises in the Khan Academy platform is presented. Finally, there is an analysis of the learning analytics features related to assessment activities that are present in MOOCs. Moreover, some guidelines are provided about how to interpret and take advantage of this information.
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Housecroft, Catherine E. "Polyoxometallates of molybdenum and tungsten". In The Heavier d-Block Metals. Oxford University Press, 1999. http://dx.doi.org/10.1093/hesc/9780198501039.003.0008.
Testo completoAbstract (sommario):
This chapter highlights polyoxometallates in which bridging oxo ligands support the metal cluster framework. It discusses the formation of oxoanions of molybdenum and tungsten in a solution and describes how the condensation of [MoO4]2- gives a polyoxoanioin or polyoxometallate. It also analyzes the condensation processes of molybdates and tungstates which are highly pH dependent, including a reaction that takes place at pH=5. The chapter then reviews the process that involves the sharing of oxygen atoms between metal centres and concomitant changes in the coordination environments of the metal centres. It introduces a method of representing the structures of polyoxometallates, which is used to represent silicates.
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Skhephe, Melikhaya. "Teachers’ Readiness for e-Learning during the COVID-19 Pandemic, South Africa". In MOOC (Massive Open Online Courses). IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.101242.
Testo completoAbstract (sommario):
The event of the COVID-19 pandemic and the respective implementation of social distancing protocols resulted in a rapid transition to online teaching and learning for most education institutions around the world, independent of whether teachers were prepared. The Corona Virus Disease −19 (COVID-19) has interrupted educational processes worldwide. The impact of COVID-19 on the educational system has gained crucial relevance in research, with the intention of identifying a scientifically based solution to this problem. This study is based on the notion that, while the pandemic’s effect is broad, a unit-level analysis can provide some insight. As a result, this study thus investigated the teachers’ readiness for e-learning during the COVID-19 pandemic. A qualitative approach, in particular a case study research design was employed, with sampling consisting of six teachers being purposively and conveniently selected. The findings revealed that teachers do not understand what e-learning is all about and how it can be implemented within the classroom. Another finding was that classrooms do not promote e-learning. The researchers recommend that; education officials need to organize continuous e-learning workshops for teachers. Classrooms need to be redesigned in order to promote e-learning.
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Pyrhönen, Heta. "Reading Affects in Raymond Chandler’s The Big Sleep". In Criminal Moves, 60–76. Liverpool University Press, 2020. http://dx.doi.org/10.3828/liverpool/9781789620580.003.0004.
Testo completoAbstract (sommario):
This chapter challenges the idea that stock genres evoke stock emotions. In the case of crime fiction, the anticipated movement is from the uncertainty of an unsolved crime towards the certainty of resolution. In the case of Raymond Chandler’s The Big Sleep, however, Marlowe’s change of mood invites readers to notice that while they are immersed in the suspense of the text, and thus rushed along on the roller-coaster of end-orientation, they also process the characters’ feelings, which do not necessarily move in the same direction or at the same pace. The emotions displayed in The Big Sleep suggest that crime fiction has a far broader emotional range. The chapter draws on these reading affects to challenge the authority of the novel’s solution.
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Rovira, Maria Del Pilar, Maria Del Mar Vilalta, Francisca M. Torrens, Maria F. Abando, Irene Mestre e Margalida Canet. "The «Museum and Inclusive Fashion» Project. A Design for All Experience at the Balearic School of Art and Design". In Universal Design 2021: From Special to Mainstream Solutions. IOS Press, 2021. http://dx.doi.org/10.3233/shti210389.
Testo completoAbstract (sommario):
International regulations about Accessibility and Design for All are clear. They provide two guidelines to ensure equality, autonomy, and non-discrimination, such as Reasonable Accommodation and Universal Design (or Design for All). Reasonable Accommodation leads to Adapted Fashion, which adjusts clothing to the body (average clothes for the average consumer). Universal Design leads to Inclusive Fashion, which creates clothes for everybody even if you have a body issue. Design for All (or Universal Design) implies projecting from the beginning to the end of the design process based on inclusion. In this context, the Museum-Foundation Juan March in Palma was the starting point to conceive, develop and communicate a collaborative and transdisciplinary design project; it was designed under the principle of Universal Design. This transdisciplinary co-design project took place during the first semester of the 2019–2020 academic year with a third-year BA in Fashion Design students. They designed an inclusive ready-to-wear fashion micro-collection, which focused on sensitizing BA in Fashion Design students, promoting a change of attitude, and fostering a better understanding of the challenges clothing design process. Students were invited to complete two online questionnaires to collect data on the project. The first survey was used to assess alumni’s perception of acquisition, development, and/or consolidation of key competences in participating students and control groups. The second survey was used to assess alumni’s activity on the project among participating students. This project was aimed at sensitizing BA in Fashion Design students, promoting a change of attitude, and a better understanding of the challenges clothing design process. After visiting the museum, getting inspired by their artists and their works of art, creating a mood board, and drawing the first sketches, two groups were created to develop an inclusive, ready-to-wear fashion micro-collection. Each collection focused on a different users’ profile: one group worked with a model with achondroplasia (woman), and the other group worked with two wheelchair models (man, woman). Despite the mixed results, the main objectives of the project were reached. As members of a school community, students must learn about other realities that differ from their everyday environment. As members of a school of design, students must be aware of an important prospective market niche and expand their fields of action that must include Design for All. In any case, human diversity is the key concept to approach user-centred design in the twenty-first century. The «Museum and Inclusive Fashion» project was part of an ongoing academic research project funded by the Balearic Government (2017–2020). This article reflects the views only of the authors, and the Balearic Government cannot be held responsible for any use which may be made of the information contained therein.
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Deamer, David W. "Sources of Organic Compounds Required for Primitive Life". In Assembling Life. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190646387.003.0009.
Testo completoAbstract (sommario):
Carbon compounds on the early Earth were not the simple mixture previously referred to as a “prebiotic soup.” Instead, there was a continuing input of organic material synthesized by geochemical and photochemical reactions in the volcanic crust and atmosphere; organic compounds were also being delivered during late accretion by the infall of interplanetary dust particles (IDPs), impacting comets, and asteroid-sized bodies. Compounds from both sources (terrestrial and not) then underwent chemical processing by volcanism, photochemistry, and mineral-driven oxidation–reduction reactions. Some of these processes were synthetic reactions that led to increasing complexity, but this was balanced by other processes such as hydrolysis and pyrolysis that degraded organic material into simpler compounds or tar-like polymers. Because the atmosphere contained no molecular oxygen, the organic compounds that formed were relatively stable as a dilute solution in the global ocean, but were also dissolved in freshwater hydrothermal pools in contact with mineral surfaces of volcanic land masses. In either case, a process was required by which the organic compounds could become sufficiently concentrated to undergo chemical reactions. Questions to be addressed: What are plausible sources of organic compounds? What is their composition and abundance? How would organic material be chemically processed on the early Earth? How can dilute organic solutes become sufficiently concentrated to undergo chemical reactions? Chapter 1 described how virtually all of the carbon now circulating in the biosphere as organic and inorganic compounds was delivered during accretion of planetesimals as the Earth formed, and it is reasonable to assume that Mars had a similar addition of carbon compounds and water after it cooled from primary accretion. On the Earth, organic substances delivered during primary accretion would have been destroyed by the heat of impacts and the moon-forming event, so the carbon compounds necessary for the origin of life were necessarily added after the Earth had cooled sufficiently for a global ocean to appear.
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Kaplan, O., e J. S. Cohen. "Nuclear Magnetic Resonance Spectroscopy Studies of Cancer Cell Metabolism". In Biological NMR Spectroscopy. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195094688.003.0030.
Testo completoAbstract (sommario):
Nuclear magnetic resonance spectroscopy (NMR) is a powerful technique that provides information on biochemical status and physiological processes both in-vitro and in-vivo. The metabolism of intact cells and tissues can be studied in a continuous manner, and thus, NMR is a unique non-invasive research tool enabling detection of the metabolic changes as they occur (Cohen et al., 1983; Morris, 1988; Daly and Cohen, 1989). The first NMR study of cellular metabolism was done some 20 years ago, when Moon and Richards reported on the diphosphoglyceric acid (DPG) and pH shifts in erythrocytes (Moon, and Richards, 1973). NMR studies of metabolism of tumor cells were initiated by Navon et al. who investigated phosphorylated compounds in Ehrlich ascites cells (Navon etal., 1977). The choice of the element and isotope for a specific study of metabolism depends on its NMR properties, and the required data. The proton has the highest NMR sensitivity, and is the most abundant nucleus in biological molecules. However, this may cause difficulties in the interpretation and assignment of the 1H NMR spectrum. Moreover, since metabolic studies are usually performed in aqueous solutions, the huge signal from the water protons should be suppressed. Similarly, the wide signals arising from proteins and membrane components should be suppressed. These problems can be addressed now by several innovative NMR methods (Daniels et al., 1976; van Zijl and Cohen, 1992). The most widely used nucleus in NMR studies of metabolism has been 31p (see reviews Cohen (1988); Kaplan et al. (1992)). Phosphorous NMR spectroscopy can provide data on energy metabolism and substrate utilization, phospholipid pathways, precise intracellular pH, and membrane permeability and ion and water distribution. The spectrum is easy to interpret, but the number of compounds which are detectable is limited. Carbon NMR is also useful for NMR studies of metabolism since it is found in most biological compounds; however, 13C has a natural abundance of only 1.1%, and 13C enrichment is necessary. Other nuclei which are used less often in NMR studies of cellular metabolism are 23Na (Gupta et al., 1984), 19F (Malet-Martino, et al., 1986), and rarely 15N (Legerton et al., 1983) and 39K (Brophy et al., 1983).
Atti di convegni sul tema "Solution Process MoO3"
1
Junyu, You, Ampomah William e Sun Qian. "Optimization of Water-Alternating-CO2 Injection Field Operations Using a Machine-Learning-Assisted Workflow". In SPE Reservoir Simulation Conference. SPE, 2021. http://dx.doi.org/10.2118/203913-ms.
Testo completoAbstract (sommario):
Abstract This paper will present a robust workflow to address multi-objective optimization (MOO) of CO2-EOR-sequestration projects with a large number of operational control parameters. Farnsworth Unit (FWU) field, a mature oil reservoir undergoing CO2 alternating water injection (CO2-WAG) enhanced oil recovery (EOR), will be used as a field case to validate the proposed optimization protocol. The expected outcome of this work would be a repository of Pareto-optimal solutions of multiple objective functions, including oil recovery, carbon storage volume, and project economics. FWU's numerical model is employed to demonstrate the proposed optimization workflow. Since using MOO requires computationally intensive procedures, machine-learning-based proxies are introduced to substitute for the high-fidelity model, thus reducing the total computation overhead. The vector machine regression combined with the Gaussian kernel (Gaussian -SVR) is utilized to construct proxies. An iterative self-adjusting process prepares the training knowledgebase to develop robust proxies and minimizes computational time. The proxies’ hyperparameters will be optimally designed using Bayesian Optimization to achieve better generalization performance. Trained proxies will be coupled with Multi-objective Particle Swarm Optimization (MOPSO) protocol to construct the Pareto-front solution repository. The outcomes of this workflow will be a repository containing Pareto-optimal solutions of multiple objectives considered in the CO2-WAG project. The proposed optimization workflow will be compared with another established methodology employing a multi-layer neural network to validate its feasibility in handling MOO with a large number of parameters to control. Optimization parameters used include operational variables that might be used to control the CO2-WAG process, such as the duration of the water/gas injection period, producer bottomhole pressure (BHP) control, and water injection rate of each well included in the numerical model. It is proven that the workflow coupling Gaussian -SVR proxies and the iterative self-adjusting protocol is more computationally efficient. The MOO process is made more rapid by squeezing the size of the required training knowledgebase while maintaining the high accuracy of the optimized results. The outcomes of the optimization study show promising results in successfully establishing the solution repository considering multiple objective functions. Results are also verified by validating the Pareto fronts with simulation results using obtained optimized control parameters. The outcome from this work could provide field operators an opportunity to design a CO2-WAG project using as many inputs as possible from the reservoir models. The proposed work introduces a novel concept that couples Gaussian -SVR proxies with a self-adjusting protocol to increase the computational efficiency of the proposed workflow and to guarantee the high accuracy of the obtained optimized results. More importantly, the workflow can optimize a large number of control parameters used in a complex CO2-WAG process, which greatly extends its utility in solving large-scale multi-objective optimization problems in various projects with similar desired outcomes.
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Corneo, Andrea, Mauro Suardi, Lorenzo Lancia, Francesco Cannarile e Alessandra Fidanzi. "A Business-Oriented Feature Selection Method for Enhancing Machine Learning Based Digital Tools Adoption in the Energy Industry". In ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/211601-ms.
Testo completoAbstract (sommario):
Abstract Objectives/Scope To ensure that predictive models based on Machine Learning (ML) techniques can be fully exploited by energy plant operators, these should be trained on "actionable" features, i.e., a set of features that are explainable and on which operators can directly act to take mitigative and/or preventive actions. To this aim, we have developed a business-oriented feature selection approach which identifies actionable features while optimizing the model predictive capability at the same time. Methods, Procedures, Process We have developed a solution which frames the feature selection step as a Multi-Objective Optimization (MOO) problem which relies on genetic algorithms as search engine. The MOO returns a set of optimal feature subsets referred to as Pareto optimal front on which the best compromise solution in terms of model performance and ‘actionability’ must be chosen. For selecting an optimal solution from the Pareto optimal front, the TOPSIS method has been embraced which automatically ranks the candidate solutions based on their relative importance that the users assign to the two objectives to be optimized. Results, Observations, Conclusions The proposed methodology has been successfully applied to a real case study concerning cracking furnaces of a petrochemical plant. The optimized predictive model resulting from the application of the developed feature selection strategy has shown to be properly suited for plant operators allowing them to easily derive insights and properly take actions based on the model output. Further, due to the agnostic nature of the proposed methodology, this can be easily extended and applied to other Energy case studies where "actionability" is a driving key for the successful adoption of digital tools based on ML models. Novel/Additive Information To the best of Authors knowledge, the proposed approach which embeds the "actionability" property of a feature as criterium in the feature selection step and automates the process of selecting an optimal solution through the TOPSIS method, is novel from a methodological point of view in the field of machine learning applied to energy transition use cases.
3
Held, Stefan, Arne Hildenbrand, Anatoli Herdt e Georg Wachtmeister. "Multiobjective Metamodel-Based Design Optimization—A Review and Classification Approach Using the Example of Engine Development". In Automotive Technical Papers. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2023. http://dx.doi.org/10.4271/2023-01-5026.
Testo completoAbstract (sommario):
<div class="section abstract"><div class="htmlview paragraph">To cope with increasing, challenging requirements and shorter development cycles, more complex, often nonlinear, systems with high interactions have to be optimized in many fields of research, such as the energy sector. As this often goes beyond the classical parameter studies-based approach, systematic optimization approaches offer a key solution. In the context of the development of energy converters, like engines, such techniques are applied to enhance efficiency and enable optimal use of energy. This review provides a comprehensive overview of the field of optimization approaches, more precisely referred to as Metamodel-Based Design Optimization (MBDO). The MBDO approaches essentially comprise three main modules: the Design of Experiment (DoE), the Response Surface Modeling (RSM), and the Multiobjective Optimization (MoO), in varying compositions. Previous reviews primarily focused on a selection of these modules, whereas this novel review equally covers and structures the modules DoE, RSM, and MoO and their combination to MBDO approaches. Many examples of these modules and MBDO implementations and their interrelationship, strengths, and limitations are discussed in detail and supplemented with many exemplary methods, e.g., from engine development. Methods from previous reviews are collected and updated with recent approaches, e.g., including new machine learning methods used in this context. Moreover, this study presents a holistic, extended classification approach to structure any MBDO method. The classification, which is based on the existence, structure, and interactions of the modules DoE, RSM, and MoO, is applied to various MBDO approaches from the literature. One recent MBDO focus of research is the development of online adaptive approaches as these allow to use valuable information obtained during the optimization process to guide the DoE or MoO. Therefore, the online adaptivity, feedback loops, and strengths and limitations of MBDO approaches are a novel focus area of this review. Recommendations and requirements for future “Fully Online MBDO” approaches with enhanced adaptability and generalizability are derived.</div></div>
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Ternauciuc, Andrei, e Vlad Mihaescu. "USE OF SOCIAL MEDIA IN MOOC - INTEGRATION WITH THE MOODLE LCMS". In eLSE 2014. Editura Universitatii Nationale de Aparare "Carol I", 2014. http://dx.doi.org/10.12753/2066-026x-14-043.
Testo completoAbstract (sommario):
The aim of this paper is to study the impact social media has in the dissemination of online courses, as well as in the educational process itself, particularly with the integration of social media tools into the popular open-source Learning Content Management System Moodle. The authors offer practical examples, based on the experiment of using social media tools integrated into an existing course on a running Moodle platform. The concept of MOOC - Massive Online Open Courses - has gained popularity in the last years, along with new supporters, as well as active users. It represents a redefining of the direction mainstream eLearning is taking, both in content and in learning typologies. Online education is appreciated by students, as it allows them to study from wherever they want (provided they have an internet connection) and almost whenever they want as long as they respect the course assignment deadlines. Collaboration and discussion forums are tools that appeal to the student body, especially if we take into account the technologies the current students grew up with. Another widespread technology in day to day life has been social media, defined as the interaction of people by which they create, share and/or exchange information and ideas in virtual communities and online social networks. One can sort social media into collaborative projects (for instance, Wikipedia), blogs and microblogs (Twitter), content communities (Youtube), social networking sites (Facebook), virtual game worlds and virtual social worlds. The conclusions thus obtained form the basis for developing a strategy/guidebook for new and existing MOOC systems, with concrete solutions for any and all Moodle based online learning platforms.
5
Cyrus, Justin, Van Wagner e Joseph Kenrick. "Leveraging Autonomous Moon-Based Rovers for Multiple, Near-Term Applications in Field Operations". In SPE Annual Technical Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/215057-ms.
Testo completoAbstract (sommario):
Abstract Lunar Outpost is an advanced technology startup specializing in the development of sophisticated robotic platforms for both space and terrestrial applications. Recognizing the need for automated site inspection and observation in industries such as upstream oil and gas, Lunar Outpost has developed the ‘Hound’ rover—a terrestrial robot designed for monitoring and gathering operational measurements of various field assets, including wellheads, flowlines, separators, tanks, pump stations, and pipelines. This paper describes the research and development efforts behind the Hound rover, focusing on the discovery of end-user requirements to effectively address industry pain points. The development process involved extensive stakeholder engagement, allowing for the identification of critical needs and challenges faced by the industry. The resulting platform was designed to meet these requirements and underwent rigorous verification and validation processes to ensure its capability and effectiveness.The research findings informed key decisions regarding prototyping, design, and the implementation of various features and capabilities. Each of these elements underwent thorough verification or validation, confirming their alignment with the original needs expressed by industry stakeholders. By addressing these needs, the Hound rover offers a comprehensive solution for autonomous monitoring and observation in the oil and gas industry.Furthermore, a comparative analysis was conducted to assess the advantages and disadvantages of implementing the Hound rover compared to existing operational procedures and other robotic platforms in use today. This analysis highlights the cost-effectiveness, improved visit frequency, enhanced observation capabilities, and strengthened regulatory compliance offered by the Hound rover. By replacing traditional site visits with autonomous systems, operators can achieve significant cost reductions, increase operational efficiency, and ensure compliance with safety and environmental regulations.The development of the Hound rover represents a transformative opportunity for the oil and gas industry. It addresses critical pain points, improves operational efficiency, and enhances worker safety. The findings and insights from this research have broader implications for the use of autonomous robotic platforms in various industries. Continued research and development efforts can further optimize these platforms and expand their applications, driving advancements in the field of robotics and automation.
6
Fulton, Tom, Yusuf Arikan, Regan Miller, Jonathan Kent Longridge e Mike Campbell. "Design and Installation of Leading Edge, Practical and Economic Mooring Systems for Commercial Scale Floating Offshore Wind Energy". In Offshore Technology Conference. OTC, 2021. http://dx.doi.org/10.4043/31318-ms.
Testo completoAbstract (sommario):
Objectives/Scope As Floating Offshore Wind moves from demonstration and pilot projects to full commercial scale, there is a need for mooring systems to be practical and economic while providing safe and efficient stationkeeping for floating wind turbines. Mooring systems for floating offshore wind must be designed to meet the needs to provide a reliable stationkeeping system, satisfy turbine motions criteria for maximum energy production, accommodate electrical power transmission cables, allow for other marine users (e.g., fishing vessels, service vessels for inspections and maintenance, etc.) and be environmentally friendly. To be commercially viable, this must be done with an understanding of the need to moor 30 or more turbines in close proximity to one another with hundreds of mooring lines. To accomplish this, there is no one perfect mooring system for all projects. This paper will investigate multiple mooring solutions including various configurations and material types and will reveal both the technical and commercial benefits of the various systems. Methods, Procedures, Process Multiple mooring systems will be designed to accommodate a 15 MW floating wind turbine. An installation methodology will be developed, and the supply chain will be investigated to enable calculation of the total installed cost of each system. Results, Observations, Conclusions The stationkeeping performance of each system will be compared as well as the economics for a large scale commercial floating wind farm. While no one system will be the clear best for all projects, guidance will be given which can aid in the selection of practical and economic mooring systems. Novel/Additive Information The paper will investigate multiple viable mooring systems from the design, procurement, and installation viewpoint to develop total installed cost estimates. This will be done while evaluating these mooring systems for a large commercial size floating wind farm while addressing the need for the supply chain to deliver industrialized solutions to deal with the large scale.
7
Ziadat, John, Marius D. Ellingsen, Karim H. Muci-Küchler, Shaobo Huang e Cassandra M. Degen. "Using Practical Examples to Motivate the Study of Product Development and Systems Engineering Topics". In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-66764.
Testo completoAbstract (sommario):
Most undergraduate mechanical engineering curricula contain one or more courses that provide an introduction to the product design and development process. These courses include some topics that, without the proper motivation, may be perceived by students as being of low relevance. In addition, they also cover topics that may seem to be somewhat abstract and difficult to apply unless they are preceded by examples that clearly illustrate their practical value. The tasks of identifying customer needs and setting target specifications are typical examples of the first scenario described above. In general, engineering students have the notion that the activities of the detailed design phase are the ones that really matter and that those activities are the ones that determine the ultimate success of a product. They are so concerned with designing the physical components of the product correctly that they spend little time and effort in other steps that are necessary to make sure that they are designing the right product. The tasks of concept generation and defining the architecture of a product are good examples of the second scenario mentioned in the first paragraph. Most students quickly proceed to pick a concept that they think is viable without carefully exploring the entire solution space. In addition, when considering relatively complex products, many students don’t spend enough time considering aspects such as defining the interfaces between different components. As a result, student teams end up with a collection of components that are individually well-designed but integrate poorly, and the end product suffers accordingly. Short, introductory examples demonstrating the importance of tasks like the ones mentioned above were created in order to get the attention of students and spark their interest in learning about such topics. These presentations were also created with the intent that they would motivate students to apply what they had learned when designing their own product or system. Through the examples, which corresponded to real-world product development efforts, students were exposed to not just well-designed and well-made products or systems that turned out to be successful, but also to products or systems that failed in the marketplace or experienced significant problems because the designers failed to adequately perform a task such as identifying customer requirements. The latter clearly showcased the importance of such tasks and conveyed the fact that good technical design work can be rendered moot by failing to put the required effort into the early stages of the development of a product or system. This paper presents the general criteria used and the approach followed to select and develop short introductory examples for the topics of identifying customer needs, setting target specifications, concept generation, and systems architecture. It briefly describes the examples selected and presents the results of a pilot assessment that was conducted to evaluate the effectiveness of one of those examples.