Auswahl der wissenschaftlichen Literatur zum Thema „JIT leverans“

ABSTRACT: This paper uses a sample of 131 just-in-time (JIT) firms and their matched non-JIT firms obtained from Kinney and Wempe with 1977–1995 Compustat data to assess whether the relationship between JIT adoption and firm performance is endogenous. Results indicate a significant positive association between JIT adoption and firm performance and strongly indicate that the decision to adopt JIT is endogenous. We also show that asset productivity, sales growth, and leverage, are important in explaining the effect of JIT adoption on performance and that firm characteristics are an important contributor to unobserved heterogeneity. Furthermore, the econometric analyses in the form of both Wooldridge 2SLS and Heckman approaches suggest that the underlying relationship between JIT adoption and performance is much stronger after controlling for endogeneity and self-selection bias and that OLS estimates are indeed biased.

Investment in knowledge management (KM) programmes is often contentious due to the challenge of meeting the need for continuous and sustainable benefits realization. In KM, the word ‘sustainable’ describes how programmes of strategies to leverage organizational knowledge remain productive over time: that they deliver strategic value to the organization. The focus of this paper falls on the constructs of the governance of KM and on its leadership, in KM strategy devopment and implementation, including risk management, financial controls and transparent evaluation mechanisms for continuous benefits realization. This paper presents a KM governance model and explores its recent validation through six case studies of large, distributed, multinational organizations, and through these introduces the granular constructs of KM governance. Exploration of the impact of KM governance on developing and implementing KM programmes in each case study organization demonstrates that there is a clear nexus between strategic KM governance and benefits realized from those programmes.

The purpose of this study is to examine and analyze the mechanisms of corporate governance, leverage and the free cash flow against the accrual earning management on LQ45 and JII Indexes during the 2010-2015 period. The number of samples in the study is 144 companies in JII index and 121 companies in JII indexs. Sampling techniques using purposive sampling method. Methods of data analysis using multiple linear regression to test and prove the hypothesis of the study. Research results showed the proxy of corporate governance mechanism with institutional ownership, managerial ownership, the proportion of Board of Commissioners and the audit committee no effect to accrual earnings management.(prob value >0.05). The free cash flow and leverage have an effect significantly to accrual earning management (prob value <0.05). Meanwhile in JII index, they have the same results. Corporate governance also no effect to accrual earning management, but the free cash flow and leverage have an effect significantly to accrual earning management. Keywords: corporate governance, leverage, free cash flow, accrual earnings management

Organizational information technology (IT) needs are served through increasingly complex configurations of people, technologies, organizations, and shared information. Ideally, an organizational IT service is valuable for both the providers and users of systems and solutions. However, mutually beneficial outcomes may be difficult to achieve within the configurations through which IT services are delivered. We suggest that analyzing stakeholder interplay in IT service processes helps us to understand how information systems (IS) organizations can be leveraged to co-create business value. Through a qualitative empirical inquiry, we explore IT service realization in two case organizations. Through our analysis we find that value creation builds on orchestrated social action among the different stakeholder groups involved. Joint value creation in IT service processes hence calls for specific network leadership and resource integration capabilities from the IS organization. The paper enriches the current understanding of business value creation in IT services by infusing the service logic with traditional IT management perspectives. The findings highlight that the extent to which the IS organization can learn to facilitate the interaction between the essential actors in an ‘IT service system’ and leverage user-perceived value throughout the service process will ultimately determine its success or failure.

The purpose of this research is to find out the role of ISR disclosure as a moderator of the relationship between profitability and leverage on firm value in companies listed in JII for the 2014-2018 period. This research uses quantitative research using Moderated Regression Analysis (MRA). This study uses secondary data in the form of panel data on companies registered in JII for the 2014-2018 period. The populations in this study are all companies registered in JII during the 2014-2018 period. The sampling method is carried out by purposive sampling by using several criteria to obtain 15 companies used as research samples. The results of this study indicate that profitability and leverage affect the value of the company. The results of the Moderated Regression Analysis (MRA) analysis show that disclosure of the ISR is able to moderate the relationship between profitability and firm value but towards the negative. However, ISR disclosure is not able to moderate the relationship between leverage and firm value.

Studies for over 30 years have consistently indicated that enterprise-level Business-Information Technology (IT) alignment is a pervasive problem. While significant progress has been made to understand alignment, research on IT alignment is still plagued by several problems. First, most alignment models approach alignment as a static relationship in contrast to analyzing the scope and variance of activities through which the alignment is (or can be) attained. Second, most alignment models are not founded on strong theoretical foundations. Third, because of their static view, these models do not guide how organizations can improve alignment. This study addresses these weaknesses using a capability-based lens. It formulates and operationalizes a formative construct rooted in the theory of dynamic capabilities and defines the scope and nature of activities that contribute to alignment. The construct identifies six dimensions promoting alignment: (1) IT-Business Communications; (2) Use of Value Analytics; (3) Approaches to Collaborative Governance; (4) Nature of the affiliation/partnership; (5) Scope of IT initiatives; and (6) Development of IT Skills. The construct measures are validated in terms of their dimensionality, item pool sampling, and the nomological and predictive validity. The research uses Partial Least Squares (PLS) to statistically validate the construct using a dataset covering over 3000 global participants including nearly 400 Fortune 1000 companies. All construct dimensions contribute significantly to the level of alignment and the construct shows strong nomological and predictive validity by demonstrating a statistically significant impact on firm performance. Scholars can leverage this research to explore additional activity-based constructs of IT-business alignment.

The aim of this paper is to evaluate the capital structure and its determinants in consumer co- operatives in the Czech Republic. Consumer co-operatives are associated in the COOP Group, which is the largest retail network of food stores in the country. This analysis uses quantitative data from the financial statements for the years 2014 to 2018 from the database of information on Czech economic entities Albertina. Financial indicators, regression as well as correlation analysis are all used to analyse the data. This paper reveals that the leverage of the entire group is low, as more than two- thirds of the assets are financed by equity. Internal financing from retained profits is prevalent. From the results of multiple linear regression analysis is apparent that tangibility and total assets turnover both have a positive effect on leverage while liquidity and retained profits negative.

Dalam menghadapi perkembangan zaman yang semakin cepat pada sektor perekonomian di Indonesia membuat perusahan berfikir untuk menemukan cara agar nilai perusahaan yang ada saat ini bisa bermanfaat untuk masa yang akan datang. Penelitian ini dilakukan untuk menguji pengaruh profitabilitas, kebijakan hutang dan dol (Degree of Operating Leverage ) terhadap nilai perusahaan yang terdaftar di Jakarta Islamic index (JII) selama periode Juni 2016 – Mei 2019. Populasi penelitian ini adalah perusahaan yang terdaftar di Jakarta Islamic Index (JII).Pengambilan sampel ditentukan dengan menggunakan purposiv sampel. Terdapat 30 sampel dalam penelitian ini berdasarkan kriteria yang telah ditentukan. Berdasarkan penelitian yang telah dilakukan,hasil yang didapat menunjukkan bahwa profitabilitas,kebijakan hutang dan dol berpengaruh signifikan terhadap nilai perusahaan. Hasil penelitian ini dilakukan dengan pengujian regresi yang menunjukkan jika profitabilitas, kebijakan hutang dan dol semakin tinggi akan meningkatkan nilai perusahaan . Manfaat dari penelitian ini adalah sebagai salah satu pertimbangan investor dalam menentukan keputusan saat akan melakukan pengambilan keputusan investasi di suatu perusahaan.

Ericsson AB har en produktionsenhet i Gävle (Sverige), CDC Gävle. Denna enhet är indelad i två fabriker, Skolgången och Avaström. På Skolgången monteras WCDMA radiobasstationer (3G) och på Avaström GSM radiobasstationer (2G).

CDC Gävle har idag ett stort returflöde av emballage från inkommande monteringsmaterial. Det förekommer också många störningar i materialförsörjningen till monteringen. CDC Gävle har beslutat att på sikt ska allt material som idag finns på lager befinna sig på hubbar.

Syftet med examensarbetet var att undersöka påfyllnaden av monteringsmaterial till linan. Påfyllnad skulle ske direkt mot linan. Resultatet av arbetet blev en teoretisk försörjningsmodell som byggde på att materialet kom från hubbar. Försörjningsmodellen skulle ta hänsyn till nuvarande systemlandskap samt att det skulle ske på ett så kostnads- och utrymmeseffektivt sätt som möjligt. Den skulle också se över problemen med emballage och störningarna i materialflödet.

Arbetet skulle besvara följande centrala frågor:

• Hur bör materialet fördelas på hubbarna?

• Vilka lastbärare är lämpliga vid levereras till linan?

• Vilka förändringar kan komma att krävas av befintliga system, arbetsmetodik samt vilka krav ska ställas?

• Var och hur bör omplock av material ske?

• Hur kommer materialflödet att se ut från hubb till monteringslina?

Arbetet har bedrivits genom datainsamling på CDC Gävles olika anläggningar. Det genomfördes även ett flertalet studiebesök för att se hur andra producerande företag arbetade med liknande frågor. Under arbetsgången har det skett kontinuerliga litteraturstudier.

Författarna belyste och tog fram ett flertal parametrar som anses avgörande vid utformningen av en ny försörjningsmodell. CDC Gävle måste besluta hur dessa parametrar ska lösas innan en fullständig implementering av hubbar kan börja. Arbetet resulterade i en försörjningsmodell som är generell för både WCDMA och GSM. Arbetet tar också upp hur hubben bör arbeta, vilka funktioner den ska innehålla samt vart den bör lokaliseras. Vidare rekommenderas lämpliga lastbärare och vilka arbetssätt som är lämpliga för CDC Gävle.

Ett av de största problemen i arbetet var att ta hänsyn till de speciella materialflödena som CDC Gävle har, detta gällde bl a reklamation och enhetspackade artiklar. Den centrala parametern i hela försörjningsmodellen var frystiden. Frystiden är den tidsperiod från att kunden inte kan ändra sin order till ordern startas på monteringen. Om det inte existerar någon frystid kommer inte hubben hinna plocka fram och leverera det material som CDC Gävle behöver.

Författarna bedömer att det finns goda möjligheter att flytta befintliga lager till hubbar. Det bör dock genomföras ett flertal piloter med olika sorters material innan man går vidare.

Ericsson AB has a production unit in Gävle (Sweden), CDC Gävle. The unit is divided into two facilities, Skolgången and Avaström. WCDMA (3G) Radio Base Stations are assembled at Skolgången and GSM (2G) Radio Base Stations are assembled at Avaström.

Today CDC Gävle has a major return flow of packing from received assembly material. There also exist several disruptions in the material supply to the assembly. CDC Gävle has decided that in the long term all material, which today is stored in the warehouse, will be stored in hubs.

The purpose of the thesis work was to investigate the replenishment of material to the line. Replenishment was to be made directly to line. The result of the thesis work became a theoretical supply model that was based on the material arriving from hubs. The supply model had to consider the present system environment and also be as cost and area efficient as possible. It was also supposed to look at the problems with packing and disruptions within the material flow.

The thesis work was to answer the following essential questions:

• How should the material be allocated to the hubs?

• Which load-carriers are appropriate on delivery to the line?

• What changes could be required of the present systems, working methods and also what requirements are to be made?

• Where and how should the re-arrangement of material be done?

• What will the material flow look like from hub to assembly line?

The thesis work has been carried out by the collection of data at CDC Gävle’s different facilities. Several study visits were conducted to see how other producing companies worked with similar questions. During the work process there have been continuous literature studies.

The authors elucidated and compiled several parameters, which were considered crucial in the design of a new supply model. CDC Gävle must decide how these parameters will be solved before a full-scale implementation of hubs can begin. The result of the thesis work was a supply model, which is common to both WCDMA and GSM. The thesis work also covers how the hub should work, which functions it will contain and where it should be located. Further, more suitable load-carriers and ways of working for CDC Gävle are recommended.

One of the biggest problems was to take into consideration of the special material flows, which CDC Gävle has; amongst those concerned were the claims flow and the unit-packed articles. The essential parameter in the whole supply model was the frozen horizon. The frozen horizon is the time period from when a customer cannot change the order to when the order is started in the assembly. If there is no frozen horizon, the hub will not have enough time to take out and deliver the material, that CDC Gävle need. The authors’ opinion is that there are good possibilities of moving the present warehouse to hubs. However several pilots should be conducted with different kinds of materials before any further step is taken.

I delar av byggbranschen finns idag ett gemensamt problem som kan beskrivas med termen dålig framförhållning. Detta försvårar möjligheten att se bygglogistiken i ett helhetsperspektiv, både för leverantören och entreprenören, men tyvärr även för övriga aktörer inblandade i byggproduktionsprojekt. Att uppnå bra bygglogistik med ökad hänsyn till miljön kräver ett gott samarbete mellan samtliga parter. Bygglogistik är planering flera (många) veckor framåt, i byggbranschen är det vanligt att det uppkommer oväntade händelser som leder till att tidsplaner för olika delar i byggprojektet justeras. I dagsläget är det lite för ofta som justeringar sker ”i sista minuten”. Detta leder till dyrare frakter, svårigheter att klara av en bra leveransprecision vilket i sin tur påverkar effektiviteten i bygglogistiken negativt. Problemen som upptäckts för de olika processerna inom bygglogistiken på Cramo är beskrivna med åtgärdsförslag, rekommendationer för effektivisering/förbättring av bygglogistik under rubriken probleminventering. För detta arbete har faktainsamlingen omfattat metoderna i lean construction som JIT- Just in time och jämförelser mellan olika tilläggstjänsterna som används i byggbranschen idag. Även fakta om kommunikationssystemet, TMS, samt läran om transport och materialhantering har undersökts och analyserats. Fakta från intervjuerna som beskriver TMS, transport metoder och lösningar samt hur hantering av material sker och vad man har för mål i framtiden har redovisats i bakgrunden, resultatet samt i analysen. Bygglogistik är kortfattat en samlings ord för alla aktiviteter som leder till att rätt produkt ska vara på rätt plats vid rätt tillfälle. “Tänk efter före”(Sundin, 2019)
In the construction industry, there is a general industry problem that can be described by the term poor advance planning. This makes it difficult to see the construction logistics in a holistic perspective, both for the supplier and the contractor, but unfortunately also for other parties involved in construction production projects. Achieving good building logistics with consideration for the environment requires good cooperation between all parties. Building logistics is planning several (many) weeks ahead, in the construction industry it is common that unexpected events arise that lead to adjusting timetables for different parts of the construction project. At present, it is a little too often that adjustments are made "at the last minute". This leads to more expensive freight, difficulties in coping with a good delivery precision, which in turn negatively affects the efficiency of construction logistics. Problems that has been discovered for the different parts of the process within building logistics in CRAMO are presented with solutions, recommendation of efficiency/improvement for building logistics under the title problem inventory,”problem inventering”. In problem inventory, these are described while action proposals are presented later in the report during the analysis. For this work, the facts have included the methods in lean construction as JIT- Just in time and comparisons between various additional services used in the construction industry today. Facts about the communication system, TMS, and the doctrine of transport and material handling have also been investigated and analyzed. Facts from the interviews that describe TMS, transport methods and solutions as well as how material handling takes place and what one has for goals in the future have been reported in the background, the result and in the analysis. Building logistics is briefly a term for all activities that lead to the right product being in the right place at the right time. "Think ahead" (Sundin, 2019)

Totalkostnaden för inköp och leverans av material kan reduceras genom att analysera fler kostnadsposter än endast inköpspriset för materialet. Ett sätt att åstadkomma detta är att tillämpa en totalkostnadsanalys för materialet från inköp till dess att det används i produktionen på byggarbetsplatsen. Studien tillämpar en totalkostnadsanalys för att jämföra och utvärdera två olika leveransmetoder av gipsskivor till lägenhetsprojektet JM Ikon. Totalkostnadsanalysen appliceras på ett lägenhetsprojekt där gipsskivorna i nuläget har lyfts in under projektets stomskede med hjälp av lyftkran och hantverkare på plats. Alternativscenariot innebär JIT-leveranser till byggarbetsplatsen via Derome Bygg och Industri där materialet bärs in så nära monteringstillfället som möjligt av Svensk Bygglogistiks Logistikpatrull. Studiens resultat bygger på en fallstudie med både kvantitativa- och kvalitativa metoder. Frågeställningarna har besvarats genom insamling av primära och sekundära data genom litteratursökning, semistrukturerade intervjuer och historiskt dokumenterade data. De semistrukturerade intervjuerna har hållits med affärsområdeschefer, affärsutvecklingschefer, produktionschefer och platschefer i syfte att samla in kvantitativa data samt information om hur arbetet på byggarbetsplatsen fungerat. Totalkostnadsanalysens resultat visar på att alternativscenariot är det mest ekonomiskt lönsamma leveransalternativet för projektet JM Ikon med en kostnadsskillnad på 44 582 kr mellan nuläget och alternativscenariot. Känslighetsanalysens resultat stärker resultaten från totalkostnadsanalysen då en brytpunkt mellan alternativen inte gått att hitta. Oberoende av vilket alternativ som är mest ekonomiskt lönsamt bör valet av leveransmetod anpassas utefter byggets specifika förutsättningar och behov så som geografisk placering, typ av byggprojekt samt dess storlek. Totalkostnadsanalysen kan användas som ett underlag vid beslut om leveransmetod vid inköp av gips och som argument vilka kostnadsbesparingar som kan göras med alternativscenariot. För vidare studier inom ämnet rekommenderar författarna att utforma ett ramverk som kan anpassas baserat på ett byggprojekts unika förutsättningar. En mer utförlig totalkostnadsanalys där fler typer av material tas med hade givit en djupare analys av de kostnader som uppstår samt hur de påverkar totalkostnaden.

Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet

Inom byggindustrin är det svårt att skapa standardiserade logistikprocesser eftersom det vid varje nytt bygge även skapas en ny organisation. Förutsättningarna skiljer sig även mellan olika byggen, vilket försvårar ett förbättringsarbete. Skanska Väg och Anläggning Norr fick under 2017 uppdraget att bygga om Vasaplan i centrala Umeå, och i september 2018 stod projektet klart. Ombyggnationen var i det stora hela ett mycket lyckat projekt, men efter färdigställandet av projektet har problem angående materialtillgång identifierats. Syftet med arbetet är att undersöka hur leveranser till en byggarbetsplats kan optimeras samt hurvida ett mellanlager kan underlätta hanteringen av leveranserna till byggarbetsplatsen. En jämförelse har gjorts där det har undersökts ifall det är mer lönsamt att använda sig av lagerhållning, eller endast av JIT-leveranser. Förhoppningen är att arbetet kan bidra till att Skanska i framtiden får ett mer standardiserat tillvägagångssätt vid planering av leveranser till byggarbetsplats av material som kräver liknande lagerhållning och transport som granithällar. För att lösa detta har två matematiska modeller använts; Anläggningslokaliseringsproblemet (ALP) samt en matematisk modell som optimerar placering av material på en lageryta. Två stycken produktionsflödesmodeller, JIT och EOQ, har även använts i beräkningarna. Resultatet från produktionsflödesmodellerna, JIT och EOQ, visar att JIT-leveranser med hjälp av en omlastningscentral alltid är den mest kostnadseffektiva lösningen då lageryta är en direkt kostnad för Skanska. I de fall lager inte är en direkt utgift för Skanska så rekommenderar den matematiska modellen för ALP en optimal användning av de lager som är tillgängliga.
For every new construction project, a new organisation is created. It is therefore a challenge for the construction industry to create standardized logistic processes. In addition, different construction projects have different traits, which results in further challenges for improvement efforts for the construction logistic processes. In 2017 Skanska Väg och Anläggning Norr did the reconstruction of Vasaplan in the central of Umeå, and in September 2018 the reconstruction project was done. The reconstruction was in its entirety a very successful project, however when the project was finished problems regarding material supply were identified. The aim of this paper is to analyze how deliveries to a construction site can be optimized and whether storage spaces can aid in the handling of deliveries to the construction site. A comparison has been made between storing material and using JIT-deliveries. The hope is to help Skanska in developing a more standardized approach when it comes to planning the deliveries of materials that has similar storage and transport conditions as the slabs of granite used. To solve this two mathematical models have been used; Facility location problem and a mathematical model that optimizes the placement of materials in a storage space. Two production flow models, JIT and EOQ, were also used when performing the calculations. The result from the production flow models, JIT and EOQ, show that JIT deliveries are always the most cost effective solution when storage space is a direct cost for Skanska, when used together with a logistics center. However, when storing is no extra expense for Skanska, the mathematical model for the Facility location problem suggests a optimal use of the storage spaces that are available.

This concluding chapter argues that the decline of forces represented by Paul Robeson meant that forces symbolized by Claude Barnett, who were surely interested in Pan-Africanism but also were seeking profitable investments, meant they were conflicting with African leaders like Kwame Nkrumah who had a socialist orientation; this was bound to create waves. Moreover, it was bound to undermine Associated Negro Press's (ANP) role as an honest broker or even as a cynical promoter of Washington's policies, all of which was hastening the agency's demise. Part of the paradox of Jim Crow was that as it eroded at a time when the Robesons were in retreat and the Nkrumahs of the world were ascending, conflict was bound to arise between Africans and African Americans, thus eroding too the global leverage that had been so instrumental in collapsing Jim Crow in the first place.

This chapter uses black-on-black homicide reports from the Memphis Police Department in the Jim Crow era to reveal the complex interactions between the police and black Memphians. The police investigated these crimes extensively, especially in light of the white public’s outcries about crime rates. Yet, this was not a simple matter of white social control. African Americans aided the police in these efforts, providing information, collecting evidence, and acting as witnesses, not because they trusted the police to protect their neighborhoods, but because they did not. Their involvement allowed them to grasp some leverage in a system under which they otherwise had very little power.

Electrohydrodynamic jet (E-jet) printing is a recent technique for high resolution additive micromanufacturing. With high resolution comes sensitivity to small disturbances, which has kept this technique from reaching its industrial potential. Closed loop control of E-jet printing can overcome these disturbances, but it requires an improved understanding of ink droplet spreading on the substrate and a physical model to predict printed feature locations and geometries from process inputs and disturbances. This manuscript examines a model of ink droplet spreading that uses assumptions that are important to the e-jet process. Our model leverages previous energy balance models that were derived for larger length scale droplets. At the smaller length scale, we find that viscous losses are a significant portion of the energy budget and must be accounted for; this is in contrast to models at length scales two orders of magnitude larger. Our model predicts the droplet height, base radius and contact angle in time from an initial volume and E-jet printing control parameters. The model is validated with published droplet spreading data and new measurements of E-jet printed droplets of diameter 8 μm. The viscous friction calculated in the new model is found to be significant compared to surface energy.

Abstract The increased need to design higher performing aerodynamic shapes has led to design optimisation cycles requiring high-fidelity CFD models and high-dimensional parametrisation schemes. The computational cost of employing global search algorithms on such scenarios has typically been prohibitive for most academic and industrial environments. In this paper, a novel strategy is presented that leverages the capabilities of Artificial Neural Networks for regressing complex unstructured data, while coupling them with dimensionality reduction algorithms. This approach enables employing global-based optimisation methods on high-dimensional applications through a reduced computational cost. This methodology is demonstrated on the efficiency optimisation of a modern jet engine fan blade with constrained pressure ratio. The outcome is compared against a state-of-the-art adjoint-based approach. Results indicate the strategy proposed achieves comparable improvements to its adjoint counterpart with a reduced computational cost, and can scale better to multi-objective optimisation applications.

The control of tip leakage flow (TLF) through the clearance gap between the moving and stationary components of rotating machines is still a high-leverage area for improvement of stability and performance of aircraft engines. Losses in the form of flow separation, stall, and reduced rotor work efficiency are results of the tip leakage vortex (TLV) generated by interaction of the main flow and the tip leakage jet induced by the blade pressure difference. The effects are more detrimental in transonic compressors due to the interaction of shock-TLV. It has been previously shown that the use of slots and grooves in the casing over tip of the compressor blades, known as casing treatment, can substantially increase the stable flow range and therefore the safety of the system but generally with some efficiency penalties. This paper presents a numerical parametric study of tip clearance coupled with casing treatment for a transonic axial-flow compressor NASA Rotor 37. Compressor characteristics have been compared to the experimental results for smooth casing with a 0.356 mm tip clearance and show fairly good agreement. Casing treatments were found to be an effective means of reducing the negative effects of tip gap flow and vortex, resulting in improved performance and stability. The present work provides guidelines for improvement of steady-state performance of the transonic axial-flow compressors and improvement of the stable operating range of the system.

The field of consumer and power electronics is surging ahead with more sophisticated and powerful devices that are smaller and more capable than before. Proper and efficient thermal management of such devices is increasingly challenging when addressing requirements to reduce size, weight and cost (both manufacturing and operational) while enabling the overall system to operate at higher power densities. The current effort considers a typical power electronic module most often used to address DC to AC voltage conversion in larger distributed energy systems. Significant heat generation results from switching and conduction losses inherent in such a circuit, which can then cause a drop in the power processing capabilities or worse, the destruction of the device itself if not properly cooled. A nominal architecture for the circuit module is selected and a combined experimental and analytical study is performed to implement an integrated micro-cooling chip architecture that leverages single phase jet-impingement and vortex flow approaches. The micro-cooling chip array is a multi-laminate design that features localized fluidic cells ducted to bring coolant in and out of a heat exchanger section. The paper reports on the design of the multi-laminate micro-cooling chip module in terms of manufacturability and fluid dynamics of the coolant in combination with the power electronics module. Results from bench-scale testing done on a monolithic part fabricated using additive manufacturing process are reported and compared with analysis. The results provide an initial basis for further miniaturization of the power electronic module and insights to manufacturability using standard 3D printing approaches.

An aircraft crash in the Netherlands was caused by disintegration of a jet engine. Fractography showed that the chain of events started with stress corrosion cracking (SCC) of a pin attached to a lever arm of the compressor variable vane system. Such a lever arm-pin assembly costs only a few dollars. Investigation of hundreds of pins from the accident and a number of identical engines revealed that this was not an isolated case. Many pins exhibited various amounts of SCC. The failed pin in the accident engine happened to be the first fractured one. SCC requires the simultaneous presence of tensile stress, a corrosive environment and a susceptible material. In this case the stress was a residual stress arising from the production method. There was a clear correlation between the presence of salt deposits on the levers and SCC of the pins. It was shown that these deposits were able to reach the internal space between the pin and lever arm, thereby initiating SCC in this space. The corrosive environment in Western Europe explains why the problem manifested itself in the Netherlands at a relatively early stage in engine life. The main point is, however, that the manufacturer selected an SCC-prone material in the design stage. The solution has been to change the pin material.