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Stripping gas is generally used to improve hydrogen yields in fermentations. Since CO2 is relatively easy to separate from hydrogen it could be an interesting stripping gas. However, a higher partial CO2 pressure is accompanied with an increased CO2 uptake in the liquid, where it hydrolyses and induces an increased requirement of NaOH to maintain the pH. This enhances the osmotic pressure in the c
The increase in efficiency of RF power generation for future large accelerators is considered a high priority issue. The vast majority of the existing commercial high-power RF klystrons operates in the electronic efficiency range between 40% and 55%. Only a few klystrons available on the market are capable of operating with 65% efficiency or above. In this paper, a new method to achieve 90% RF pow
Our future built environment will not only consume energy, it will also produce (partly) its own energy need. Solar energy has been proven to be a valid strategy for producing on-site renewable energy. Planning for integrating solar energy in buildings involves many players and decision-making. In this article, a process map defining which decisions regarding solar energy needs to be discussed in
Energy security, climate change and air pollution are all motivations for further development of fuel cells. Still, technical problems relating to water management, continue to hinder the marketability of polymer electrolyte fuel cells (PEFCs). The impact of dynamic contact angle (CA) boundary conditions, according to the Kistler model, is evaluated in this paper with the VOF approach, focusing on
Biorefinery applications are receiving growing interest due to climatic and waste disposal issues and lack of petroleum resources. Jerusalem artichoke (Helianthus tuberosus L.) is suitable for biorefinery applications due to high biomass production and limited cultivation requirements. This paper focuses on the potential of Jerusalem artichoke as a biorefinery crop and the most viable products in
This report analyses the technical opportunities for a complete decarbonisation of the basic material industry in Sweden by 2050. From this assessment, the report discusses policy implications for the industry sector given the overall framework set by the ongoing international climate negotiations. Relying on current production systems and applying “end-of-pipe” solutions will be insufficient to
This study presents a survey of the most important techno-economic factors for the implementation of biorefineries based on agricultural residues, in the form of straw, and biochemical conversion into ethanol and biogas, together with production of electricity and heat. The paper suggests locations where the necessary conditions can be met in Sweden. The requirements identified are regional availa
Den här uppsatsen handlar om preventivt självförsvar och huruvida detta är tillåtet enligt folkrätten, särskilt med utgångspunkt i FN-stadgan. Preventivt självförsvar kan förklaras som rätten att slå till mot en fiende som planerar att angripa en själv, innan denna fiende hunnit genomföra sin attack. Idén om preventivt självförsvar inom folkrätt är inget nytt, ledare över hela världen har genom ti
Cell immobilization and co-culture techniques have gained attention due to its potential to obtain high volumetric hydrogen productivities (QH2). Chitosan retained biomass in the fermentation of co-cultures of Caldicellulosiruptor saccharolyticus and C. owensensis efficiently, up to a maximum dilution rate (D) of 0.9 h−1. Without chitosan, wash out of the co-culture occurred earlier, accompanied w
For district heating systems, prediction of the heat load is a very important topic for energy storage and optimized operation. For large and complex heating systems, most prediction models in previous publications only considered the influence of outdoor temperature, whereas the indoor temperature and thermal inertia of buildings were not included. For an energy-efficient residential building in
Heat transfer enhancement is of great importance for energy efficiency improvement. The utilization of spirally corrugated tubes is one of the efficient ways to strengthen heat transfer. In this article, based on a validated numerical model, the effects of geometric parameters of a six-start spirally corrugated tube, including the pitch p and the corrugation depth e, on the shell side heat transfe
The aim of this study is to develop a model capable of predicting the behavior of a district heating substation, including being able to distinguish datasets from well performing substations from datasets containing faults. The model developed in the study is based on machine learning algorithms and the model is trained on data from a Swedish district heating substation. A number of different mode
The idea of using the thermal mass of a building to maintain a more constant indoor climate is not new. This particular propertyof a building, including its exterior envelope, plays an important part in the reduction of peak power demands, which is becomingan increasingly urgent issue for the heating energy suppliers. The latest smart-grid technology creates new opportunities wherecommunication be
The need for new renewable products has enhanced the interest in cellulose and hemicellulose as raw material. The wood plant cell wall is a complex mixture of cellulose, hemicellulose, lignin and minor amounts of pectin, proteins and extractives. Several interactions between the compounds make them difficult to separate without modification. O-acetyl-galactoglucomannan (O-acetyl-GGM), the major he
The German “Energiewende” (energy transition) is meant to be a contract between generations. The rebuilding of the whole energy system is designed and financed today in order to safeguard our children and grandchildren against fundamental risks: the enormous economic, social and environmental costs of a fossil-nuclear energy system, the risks of the nuclear fuel-cycle and the impacts of climate ch
Lignocellulosic materials, such as wood, waste products from the forestry industry, agricultural residues and herbaceous crops, serve as an abundant and comparatively cheap feedstock with the potential to be used for large-scale ethanol production. However, the complex structure of lignocellulosic materials, the presence of various hexose and pentose sugars in hemicellulose, and the presence of va
This study is a part of a Nordic co-operative research project, Climate and Energy, funded by Nordic Energy Research and the Nordic energy sector. The project has the objective of a comprehensive assessment of the impact of climate change on Nordic renewable energy resources including hydropower, wind power, biofuels and solar energy. In this paper, the long term variability of precipitation, temp
Until recently, the methylotrophic yeasts, including Hansenula polymorpha, have not been considered as a potential producer of biofuels, particularly, ethanol from lignocellulosics. However it is already known that the thermotolerant methylotrophic yeast H. polymorpha is capable to ferment xylose, glucose and cellobiose, the main sugars of lignocellulosic hydrolysates, under elevated temperature.
The Swedish parliament has decided that by 2045, Sweden will not be a net emitter of greenhouse gases. There is also a goal to have a fossil fuel free transport sector by 2030. However, the transport sector is still dominated by fossil fuels and many efforts are needed to lower emissions. Sweden has a relatively high share of biofuels, around 20% of the energy use in domestictransportation. Howeve
This study examines renovation strategies among owners of rental housing in Sweden in response to European energy policies that promote deep renovation as a means to reduce carbon emissions from residential buildings. Case studies of eleven housing companies, seven public and three private, were designed with the aim to examine housing owners' attitudes and renovation strategies, and how policies
