Infiltration sintering of WCu alloys from copper-coated tungsten composite powders for superior mechanical properties and arc-ablation resistance

W70Cu30(W-30 wt.% Cu) alloys were fabricated using cold pressing and infiltration sintering methods from two types of powders, i.e., mixed copper-tungsten (M-Cu-W) powders and our newly developed copper-coated tungsten composite (Cu@W) powders. Microstructure, mechanical and arc-ablation properties of the W70Cu30 alloys were investigated, and the mechanism of enhanced physical/mechanical properties and arc-erosion resistance of the W70Cu30 alloys was discussed. For the W70Cu30 alloys prepared using the Cu@W powders, their physical properties, including hardness, electrical conductivity and relative density were much better than those prepared from the M-Cu-W powders. The W70Cu30 alloys fabricated from the Cu@W powders were free of cracks, and showed homogenous distributions of W and Cu network structures. Whereas for the alloys prepared from the M-Cu-W powders, segregation of Cu was observed and the segregation size was about 40–100 μm. Characterization of arc-erosion morphologies of the W70Cu30 alloys prepared with the Cu@W powders revealed the occurrence of evaporation of Cu phase; whereas that of W70Cu30 alloys prepared with the M-Cu-W powders revealed the occurrence of the sputtering of Cu. After arc breakdown for 200 times, mass loss of alloys made using the mixed powders was twice as much as those made using the coated composite powders. Based on the experimental results and theoretical analysis, an arc breakdown mechanism of the WCu-C alloys using the composite powders was proposed which is attributed to the formation of a homogeneous Cu-Cu network structure to uniformly disperse arc energy and dissipate the generated heat, thus prolonging the service life of the WCu alloy contacts

Dopamine receptor signaling molecules are altered in elderly schizophrenic cortex

Alterations of molecules that mediate dopaminergic signal transduction have been found in schizophrenia, supporting the hypothesis of altered dopaminergic neurotransmission in this illness. To further explore this hypothesis, the authors measured transcript expression of three proteins involved in dopamine (DA) signaling in postmortem dorsolateral prefrontal and anterior cingulate cortex of elderly schizophrenic subjects and a comparison group. The transcript encoding calcyon, a protein that potentiates crosstalk between D1 DA receptors and G q/11 -linked receptors, was increased in schizophrenic prefrontal and cingulate cortex by 25%. Transcript levels of spinophilin, a protein enriched in dendritic spines that modulates excitatory neurotransmission, were increased 22% in dorsolateral prefrontal cortex but were unchanged in anterior cingulate cortex in schizophrenia. Levels of DARPP-32 mRNA, a downstream effector of dopaminergic neurotransmission, were similar in both groups for both cortical groups. These alterations in spinophilin and calcyon mRNA levels in schizophrenic prefrontal and cingulate cortex provide further evidence of altered dopaminergic neurotransmission in this illness. Synapse 60:271–279, 2006. © 2006 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55792/1/20292_ftp.pd

Supporting the Complex Social Lives of New Parents

One of the many challenges of becoming a parent is the shift in one’s social life. As HCI researchers have begun to investigate the intersection of sociotechnical system design and parenthood, they have also sought to understand how parents’ social lives can be best supported. We build on these strands of research through a qualitative study with new parents regarding the role of digital technologies in their social lives as they transition to parenthood. We demonstrate how sociotechnical systems are entangled in the ways new parents manage their relationships, build (or resist building) new friendships and ad hoc support systems, and navigate the vulnerabilities of parenthood. We discuss how systems designed for new parents can better support the vulnerabilities they internalize, the diverse friendships they desire, and the logistical challenges they experience. We conclude with recommendations for future design and research in this area

Greenhouse in Vaksala Eke

This project has been carried out on the behalf of IHUS and the aim was to find a solution to a greenhouse with an associated café on Vaksala Eke just north of Uppsala. This complex is intended to be self-sufficient on heat, electric power and crops. In the project we have created a greenhouse that fully supplies the café with crops during the summer, while during the winter the greenhouse only provides 8-16% of the café’s demand of crops. Six different scenarios were created to cover the heat demand of the greenhouse and the café. The following scenarios for the heat supply were considered: ground heat; solar thermal energy and ground heat; geothermal energy; solar thermal energy and geothermal energy; bioenergy; solar thermal energy and bioenergy. These six scenarios were compared to one another to obtain the most profitable system. The results showed that the scenario with the shortest payback period for heat generation, is the ground heat scenario. Photovoltaic solar panels is the only source of electric power examined for the small-scale operation on Vaksala Eke. All the scenarios, except for the scenarios with bioenergy, were fully self-sufficient on heat, on the other hand all the scenarios were self-sufficient on electricity over a year.Detta arbete har genomförts på uppdrag av IHUS och har gått ut på att ta fram en lösning för ett växthus med tillhörande café på Vaksala Eke, norr om Uppsala. Anläggningen avsågs att vara självförsörjande på energi och grödor. I projektet har det skapats ett växthus som förser caféet till 100% med grödor under sommaren och på vintern med 8-16%. Sex olika scenarier skapades vilka alla skulle täcka värmebehovet till växthuset och caféet. Följande scenarier för värmeförsörjningen undersöktes: jordvärme; solvärme och jordvärme; bergvärme; solvärme och bergvärme; bioenergi; solvärme och bioenergi. Dessa sex scenarier jämfördes för att ta fram det mest lönsamma systemet. Resultatet visar att scenariot med kortast återbetalningstid är det när värmetillförseln enbart kommer från jordvärme. Solceller bedömdes som det enda rimliga alternativet för den småskaliga verksamheten på Vaksala Eke varför endast denna elkraftkälla undersöktes. De scenarier som ej innehöll bioenergi blev helt självförsörjande på värme, och över ett år blev alla scenarier självförsörjande på elkraft

Energy and power quality mapping of a coater oven

The energy market is developing rapidly, with renewable energysources yearly winning market shares. To maintain this growth andto expand into the transport sector it must become cheaper and moreavailable to store electric energy. Lithium-ion batteries are oneof the most promising candidates for achieving this. But to producethese batteries large amounts of energy are needed. It is thereforecritical to minimise the power usage when constructing thesebatteries.The purpose of this master thesis was to map the energy usage of acoater oven and to locate weak spots in the process. It was done byanalysing the power usage and estimating the energy in the exhaustair being dispatched from the oven and other losses. The results highlighted that the coater oven’s existing heatexchanger was performing poorly and became worse with lower airtemperatures leaving the oven. It was also concluded that some ofthe equipment powering the oven was over-dimensioned and as aresult had a power factor much lower than optimal. This was leadingto an unnecessary high reactive power consumption. It was alsoshown that the oven at higher loads was able to produce morematerial per kWh, hence being the most energy efficient way ofoperating it.It can therefore be summarised that the best way of operating theoven is at higher loads. It is the most energy efficient option andis at the same time minimising the percentage of reactive powerusage, thereby also lowering some heat losses. It also comes withthe advantage of improving the efficiency of the heat exchanger, aheat exchanger performing at poorly levels and in need of a rework.

Who wants to work remotely? : A quantitative study that examines students' attitudes towards remote work

Studenter kommer idag ut på en förändrad arbetsmarknad där distansarbete är det nya normala. Syftet med denna studie är att undersöka eventuella samband mellan studenters attityd till distansarbete på sina framtida arbetsplatser och faktorerna kön, upplevelser av distansstudier och personlighet. Studien är en kvantitativ enkätstudie där urvalet består at universitetsstudenter. Resultatet visade på en statistiskt signifikant skillnad i attityd till distansarbete mellan könen. Därtill hittades ett positivt statistiskt signifikant samband mellan upplevelser av distansstudier och attityd till distansarbete. Inga statistiskt signifikanta samband hittades mellan attityd till distansarbete och personlighet. I linje med tidigare forskning fann denna studie att majoriteten av studenterna hade en positiv attityd till distansarbete såväl som att både män och kvinnor helst ville arbeta två datar i veckan på distans. Studiens slutsats är att tidigare upplevelser av distansstudier var den främsta förklaring till studenters attityd till distansarbete. Kvinnliga studenter hade en mer positiv attityd till distansarbete än manliga studenter och personlighet tycks inte vara avgörande för attityd till distansarbete.

Energy and power quality mapping of a coater oven

The energy market is developing rapidly, with renewable energysources yearly winning market shares. To maintain this growth andto expand into the transport sector it must become cheaper and moreavailable to store electric energy. Lithium-ion batteries are oneof the most promising candidates for achieving this. But to producethese batteries large amounts of energy are needed. It is thereforecritical to minimise the power usage when constructing thesebatteries.The purpose of this master thesis was to map the energy usage of acoater oven and to locate weak spots in the process. It was done byanalysing the power usage and estimating the energy in the exhaustair being dispatched from the oven and other losses. The results highlighted that the coater oven’s existing heatexchanger was performing poorly and became worse with lower airtemperatures leaving the oven. It was also concluded that some ofthe equipment powering the oven was over-dimensioned and as aresult had a power factor much lower than optimal. This was leadingto an unnecessary high reactive power consumption. It was alsoshown that the oven at higher loads was able to produce morematerial per kWh, hence being the most energy efficient way ofoperating it.It can therefore be summarised that the best way of operating theoven is at higher loads. It is the most energy efficient option andis at the same time minimising the percentage of reactive powerusage, thereby also lowering some heat losses. It also comes withthe advantage of improving the efficiency of the heat exchanger, aheat exchanger performing at poorly levels and in need of a rework.