A MILP Optimization Method for Building Seasonal Energy Storage: A Case Study for a Reversible Solid Oxide Cell and Hydrogen Storage System

A new method for the optimization of seasonal energy storage is presented and applied in a case study. The optimization method uses an interval halving approach to solve computationally demanding mixed integer linear programming (MILP) problems with both integer and non-integer operation variables (variables that vary from time step to time step in during energy storage system operation). The seasonal energy storage in the case study uses a reversible solid oxide cell (RSOC) to convert electricity generated by solar photovoltaic (PV) panels into hydrogen gas and to convert hydrogen gas back to electricity while also generating some heat. Both the case study results and the optimization method accuracy are examined and discussed in the paper. In the case study, the operation of the RSOC and hydrogen storage system is compared with the operation of a reference system without energy storage. The results of the study show that installing an RSOC and hydrogen storage system could increase the utilization of onsite renewable energy generation significantly. Overall, the optimization method presents a relatively accurate solution to the case study optimization problem and a sensibility analysis shows a clear and logical pattern

Challenges without the Classroom

The development of ITC has increased focus onto distance learning programs worldwide. Most universities today offer distance learning programs that are based on the Internet. This development represents a fundamental change in the very logic of being a university. It is no longer enough to rely on professor authority. How can one create a learning situation that enables the university to remain viable? In most western countries, the professors have dominated the learning processes at universities. Since the 50-ties, learning has been about learning-in, memorizing, and cram (Illeris, 2000) where professors most often decide what and when one could learn by providing the context and substance. In this perspective, the student has a role which is close to the one of a passive receiver, and s/he is mainly preoccupied with the problem of generating substance in memory most efficiently. Today, technology challenges our pedagogical reasoning in many ways. However, old pedagogical models often prevail. We see practices where lectures, notes and course information are published on the Internet, where ICT helps professor-student communication, and online based student tests. These attempts are based on old-time educational logic. There are fewer attempts to use ICT according to a different pedagogical perspective than the old professor authoritarian model. The purpose of this paper is to illuminate some challenges virtual students experience when facing a new ICT-based learning situation. We will try to explore and develop understandings of what it might mean to be a student when learning occurs within a virtual problem based learning landscape. When students are used to the traditional classroom, challenges appear in the twilight zone between two pedagogical practices. How do the students cope with challenges that a new virtual program demands, and what paradoxes and ambiguities appear when old learning processes do not work anymore? The present focus reflects an existential-phenomenological point of departure. This perspective is based on the philosophical writings of Søren Kierkegaard and Martin Heidegger (1927/1996; "Being and Time”), and the successors Hans-Georg Gadamer and Paul Ricoeur. The work is also inspired of the father of culturalism – Jerome Bruner (1996) and Wenger’s (1998) community of practice. Thompson (1997) is an inspiration through his initiator of hermeneutical endeavor within consumer research. The consequences of this perspective are that the student and his/her experiences and learning cannot be separated from the student’s existence. As for the subject matter, we cannot separate the student from his/her studying. Learning becomes a profoundly socio-cultural process which has to be studied according to the situation and context in which it appears. It is the heart of this project that the twilight zone between cultural roles might reveal some interesting knowledge about the introduction of ICT and its consequences. The socio-cultural conditions of present society set the context for the hermeneutic analysis of meanings and salient life concerns that learning experiences hold for time-pressured virtual students with high degree of responsibilities. An existential-phenomenological assumption is that individuals would tend to interpret their experiences within present socio-cultural framework. Due to its novel characteristics of the program, however, it is particularly interesting to investigate the role that virtual studying serves in the construction of reality and meaning. Furthermore, as it is assumed that experiences cannot be separated from who one is (being-in-the world), the process of human change during virtual studying is also expected to influence salient types of learning, the student’s work practice, and his/her private practice

Hantering av datamängder, programvaror och rådata vid SLU

En enkät skickades till forskare vid Sveriges lantbruksuniversitet (SLU) med frågor rörande deras hantering av forskningsdata, exempelvis vilka datatyper och mjukvaror de använder och hur stora datavolymer de hanterar, deras kunskaper om juridiska aspekter på datahantering och deras attityder till att göra data öppet tillgängliga. I rapporten diskuteras svaren på enkätfrågorna och deras implikationer för framtida arbete med datakurering vid universitetet

The immersion freezing behavior of ash particles from wood and brown coal burning

It is generally known that ash particles from coal combustion can trigger ice nucleation when they interact with water vapor and/or supercooled droplets. However, data on the ice nucleation of ash particles from different sources, including both anthropogenic and natural combustion processes, are still scarce. As fossil energy sources still fuel the largest proportion of electric power production worldwide, and biomass burning contributes significantly to the global aerosol loading, further data are needed to better assess the ice nucleating efficiency of ash particles. In the framework of this study, we found that ash particles from brown coal (i.e., lignite) burning are up to 2 orders of magnitude more ice active in the immersion mode below −32 °C than those from wood burning. Fly ash from a coal-fired power plant was shown to be the most efficient at nucleating ice. Furthermore, the influence of various particle generation methods on the freezing behavior was studied. For instance, particles were generated either by dispersion of dry sample material, or by atomization of ash–water suspensions, and then led into the Leipzig Aerosol Cloud Interaction Simulator (LACIS) where the immersion freezing behavior was examined. Whereas the immersion freezing behavior of ashes from wood burning was not affected by the particle generation method, it depended on the type of particle generation for ash from brown coal. It was also found that the common practice of treating prepared suspensions in an ultrasonic bath to avoid aggregation of particles led to an enhanced ice nucleation activity. The findings of this study suggest (a) that ash from brown coal burning may influence immersion freezing in clouds close to the source and (b) that the freezing behavior of ash particles may be altered by a change in sample preparation and/or particle generation

Luteinizing hormone and different genetic variants, as indicators of frailty in healthy elderly men

We investigated the possible clinical correlates between the serum LH concentration and characteristics of frailty and determined the presence and concentration of a genetic LH variant in an independently living population of elderly men. After exclusion of subjects with severe mobility problems and signs of dementia, 403 healthy men (aged 73-94 yr) were randomly selected from a population-based sample. Total testosterone (T), sex hormone-binding globulin (SHBG), and leptin were determined by RIA. Non-SHBG-bound T was calculated. LH and the presence of the genetic LH variant were measured using immunofluorometric assays. The characteristics of frailty were leg extensor strength using dynamometry, bone mineral density of total body and proximal femur, and body composition, including lean mass and fat mass, measured by dual energy x-ray absorptiometry. Disability was further assessed by the Modified Health Assessment Questionnaire and by a measure of physical performance. LH significantly increased with age and inversely correlated with T and non-SHBG-bound T. LH was inversely related to muscle strength and lean mass, and both relations were independent of T. LH was positively related to self-reported disability (Modified Health Assessment Questionnaire); 12.5% of the study population was heterozygous for the LH variant allele. T levels and the degree of frailty were not different in the wild-type LH group compared with the heterozygote LH variant group. A significant positive relation between LH and fat mass as well as leptin was only present in the heterozygote LH variant group. In conclusion, serum LH levels increases with age in independently living elderly men and correlates inversely with a variety of indicators of frailty. The observed relation between LH and frailty, independent of T, suggests that LH reflects serum androgen activity in a different way than T, possibly reflecting more closely the combined feedback effect of estrogen and androgen. A difference in biological response between the two LH forms is suggested, as a difference exists in the relation between LH and fat mass, respectively, and leptin in the heterozygote LH variant subjects vs. the wild-type LH subjects

Recommended practices for wind farm data collection and reliability assessment for O&M optimization

The paper provides a brief overview of the aims and main results of IEA Wind Task 33. IEA Wind Task 33 was an expert working group with a focus on data collection and reliability assessment for O & M optimization of wind turbines. The working group started in 2012 and finalized the work in 2016. The complete results of IEA Wind Task 33 are described in the expert group report on recommended practices for "Wind farm data collection and reliability assessment for O & M optimization" which will be published by IEA Wind in 2017. This paper briefly presents the background of the work, the recommended process to identify necessary data, and appropriate taxonomies structuring and harmonizing the collected entries. Finally, the paper summarizes the key findings and recommendations from the IEA Wind Task 33 work

A Review of Virtual Reality Based Training Simulators for Orthopaedic Surgery

This review presents current virtual reality based training simulators for hip, knee and other orthopaedic surgery, including elective and trauma surgical procedures. There have not been any reviews focussing on hip and knee orthopaedic simulators. A comparison of existing simulator features is provided to identify what is missing and what is required to improve upon current simulators. In total 11 total hip replacement pre-operative planning tools were analysed, plus 9 hip trauma fracture training simulators. Additionally 9 knee arthroscopy simulators and 8 other orthopaedic simulators were included for comparison. The findings are that for orthopaedic surgery simulators in general, there is increasing use of patient-specific virtual models which reduce the learning curve. Modelling is also being used for patient-specific implant design and manufacture. Simulators are being increasingly validated for assessment as well as training. There are very few training simulators available for hip replacement, yet more advanced virtual reality is being used for other procedures such as hip trauma and drilling. Training simulators for hip replacement and orthopaedic surgery in general lag behind other surgical procedures for which virtual reality has become more common. Further developments are required to bring hip replacement training simulation up to date with other procedures. This suggests there is a gap in the market for a new high fidelity hip replacement and resurfacing training simulator

Mutation update and genotype-phenotype correlations of novel and previously described mutations in TPM2 and TPM3 causing congenital myopathies

Mutations affecting skeletal muscle isoforms of the tropomyosin genes may cause nemaline myopathy, cap myopathy, core-rod myopathy, congenital fiber-type disproportion, distal arthrogryposes, and Escobar syndrome. We correlate the clinical picture of these diseases with novel (19) and previously reported (31) mutations of the TPM2 and TPM3 genes. Included are altogether 93 families: 53 with TPM2 mutations and 40 with TPM3 mutations. Thirty distinct pathogenic variants of TPM2 and 20 of TPM3 have been published or listed in the Leiden Open Variant Database (http://www.dmd.nl/). Most are heterozygous changes associated with autosomal-dominant disease. Patients with TPM2 mutations tended to present with milder symptoms than those with TPM3 mutations, DA being present only in the TPM2 group. Previous studies have shown that five of the mutations in TPM2 and one in TPM3 cause increased Ca2+ sensitivity resulting in a hypercontractile molecular phenotype. Patients with hypercontractile phenotype more often had contractures of the limb joints (18/19) and jaw (6/19) than those with nonhypercontractile ones (2/22 and 1/22), whereas patients with the non-hypercontractile molecular phenotype more often (19/22) had axial contractures than the hypercontractile group (7/19). Our in silico predictions show that most mutations affect tropomyosin–actin association or tropomyosin head-to-tail binding

Garden and landscape-scale correlates of moths of differing conservation status: significant effects of urbanization and habitat diversity

Moths are abundant and ubiquitous in vegetated terrestrial environments and are pollinators, important herbivores of wild plants, and food for birds, bats and rodents. In recent years, many once abundant and widespread species have shown sharp declines that have been cited by some as indicative of a widespread insect biodiversity crisis. Likely causes of these declines include agricultural intensification, light pollution, climate change, and urbanization; however, the real underlying cause(s) is still open to conjecture. We used data collected from the citizen science Garden Moth Scheme (GMS) to explore the spatial association between the abundance of 195 widespread British species of moth, and garden habitat and landscape features, to see if spatial habitat and landscape associations varied for species of differing conservation status. We found that associations with habitat and landscape composition were species-specific, but that there were consistent trends in species richness and total moth abundance. Gardens with more diverse and extensive microhabitats were associated with higher species richness and moth abundance; gardens near to the coast were associated with higher richness and moth abundance; and gardens in more urbanized locations were associated with lower species richness and moth abundance. The same trends were also found for species classified as increasing, declining and vulnerable under IUCN (World Conservation Union) criteria