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AbstractBACKGROUNDEnzymatic hydrolysis of cellulose in lignocellulosic materials suffers from slow reaction rates due to limited access to enzyme adsorption sites and to the high crystallinity of the cellulose. In this study, an attempt was made to facilitate enzymatic hydrolysis by pretreatment of cellulosic materials using the ionic liquid (IL) 1‐allyl‐3‐methylimidazolium formate ([Amim][HCO2]) under mild reaction conditions. The effect of the IL was compared with that of thermochemical pretreatment under acidic conditions.RESULTSThe lignocellulosic substrates investigated were native and thermochemically pretreated Norway spruce and sugarcane bagasse. Microcrystalline cellulose (Avicel) was included for comparison. The IL treatments were performed in the temperature range 45–120 °C and, after regeneration and washing of the cellulosic substrates, enzymatic saccharification was carried out at 45 °C for 72 h. After 12 h of hydrolysis, the glucose yields from regenerated native spruce and sugarcane bagasse were up to nine times higher than for the corresponding untreated substrates. The results also show positive effects of pretreatment using [Amim][HCO2] on the hydrolysis of xylan and mannan.ConclusionThe present work demonstrates that both native wood and agricultural residues are readily soluble in [Amim][HCO2] under gentle conditions, and that pretreatment with ionic liquids such as [Amim][HCO2] warrants further attention as a potential alternative to conventional pretreatment techniques. © 2013 Society of Chemical Industry

Several efforts have been directed lately towards the endogenisation of transport modes competition in Energy/Economy/Environment/Engineering (E4) models. TIMES-DKEMS is a novel methodology paving the way for applying elasticities of substitution to incorporate transport modal shift into TIMES (The Integrated MARKAL-EFOM System) models. Substitution elasticities are defined for four transport demand aggregates, each corresponding to a different distance range class. Within an aggregate, modal demands can adjust their levels according to the defined substitution elasticity and in response to changes of their shadow prices relative to a reference case. The total volume of the transport demand over the aggregate is conserved and modal shift potentials are implemented to guarantee realistic dynamics. The behavior of TIMES-DKEMS is tested under an arbitrary environmental policy, an increasingly stringent bound on CO2 emissions. Modal shares are compared with the standard version of TIMES-DK. Results show that in 2050, 11% of car mobility demand is substituted by more efficient and less costly modes such as train and coach. A sensitivity analysis on the values of substitution elasticities indicates that higher absolute values correspond to larger modal shift. Finally, other model constraints, such as mode-specific travel patterns, interact with the substitution mechanism resulting in a modal shift containment.

PurposeThe purpose of this paper is to establish a methodological framework to address key issues in electricity distribution network development. The paper defines subtasks in the strategy process and presents key elements in the strategy work and long‐term network planning. The results are illustrated by a case network.Design/methodology/approachThe paper describes the methodology for cost and reliability analyses in the strategy work. The focus is on techno‐economic feasibility of certain network development technologies in the network strategy and the surveys are linked to economic regulation, specifically to reliability of supply and allowed return. The study addresses the stages of strategic decision making and compilation of investment strategies.FindingsThe strategic planning concept and methods are applicable in practice; the results have proven valuable in the long‐term business development and in discussions with the company owners. Outage costs are an essential element in the economic regulation of the business, reliability being a key driver in network planning.Research limitations/implicationsThere is no universal solution to strategic decision making, but each development task is highly case specific. This is due to diverging operating environments and targets set by the company owners; these issues strongly influence the strategy process.Practical implicationsThe work illustrates strategic planning in an actual distribution company and shows how the methodology can be applied to the strategic network development. Nevertheless, the results cannot be generalised as such, but each network has to be considered individually.Originality/valueThe proposed concept can be applied to the long‐term development of distribution networks. The results are internationally applicable, yet diverging regulatory models call for specific methodology in each country.

In this paper, the results of the energy efficiency and power loss measurements of a 16 kVA customer-end inverter (CEI) unit are analyzed. The CEI is part of the low-voltage dc (LVDC) distribution network. The efficiency of the CEI power conversion significantly affects the energy efficiency of the LVDC distribution network and the electricity supply chain. The efficiency of the CEI and its components is measured by applying calorimetric and electrical input-output methods. The power loss measurement results are analyzed, and the power loss mechanisms are described. The efficiency optimization goals are discussed and set.

The objective of the present research concerns the competitive photocatalytic oxidation (PCO) and adsorption of steroid estrogens (SEs) on titanium dioxide in presence of urea. The results showed the indifference of SEs towards the presence of urea in concentrations characteristic for the domestic sewage. The selective PCO of SEs appeared to be feasible in alkaline media, in which the PCO exhibited the highest efficiency. Ethanol used for hydrophobic SEs dissolution in water appeared to be interfering with the PCO.

The most PCMs with high energy storage density have an unacceptably low heat conductivity and hence internal heat transfer enhancement techniques such as fins or other metal structures are required in latent heat thermal storage (LHTS) applications. Previous work has concentrated on numerical and experimental examination in determining the influence of the fins in melting phase change material. This paper presents a simplified analytical model based on a quasi-linear, transient, thin-fin equation which predicts the solid–liquid interface location and temperature distribution of the fin in the melting process with a constant imposed end-wall temperature. The analytical results are compared to the numerical results and they show good agreement. Due to the assumptions made in the model, the speed of the solid–liquid interface during the melting process is slightly too slow.

The significant benefits of preemptive arc-flash protection and the online condition monitoring of electrical equipment are quite well known. Our continuing research focuses on the development of new advanced sensor technologies that are cost-effective, reliable, and efficient for the early detection of faults in order to predict impending arc-flash occurrences in mediumvoltage and low-voltage switchgear and controlgear. More extensive and detailed measurements regarding significant defects that lead to an arc-flash event have been completed since the original work in Part I was completed. A more detailed analysis of the results of this additional testing is presented in this paper. It has been documented that the two major noncontact causes that lead to an arc-flash event in switchgear are insulation degradation and thermal stresses. This paper covers the detailed measurement results under both of these conditions. New sensor technologies for both the partial discharge measurement and the thermal detection are introduced and evaluated. An effective signal processing technique, which is needed for extracting the essential indication of a developing fault, is also presented. Finally, this paper outlines how a preemptive arc detection system can be connected to protection, the programmable logic controller, or the supervisory control and data acquisition.