| 911. |
- Lawrence, Akvile, et al.
(författare)
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Effects of firm characteristics and energy management for improving energy efficiency in the pulp and paper industry
- 2018
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Ingår i: Energy. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0360-5442 .- 1873-6785. ; 153, s. 825-835
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Tidskriftsartikel (refereegranskat)abstract
- The Swedish pulp and paper industry (PPI) must increase energy efficiency to remain competitive on the global market, which has experienced entries from countries with cheaper energy and raw material supplies. Interactions among variables for energy use, production, energy management, electricity price and firm characteristics (FC), in different types of mills, i.e., pulp, paper and integrated mills, in Sweden from 2006 to 2015 indicate that correlations among the studied variables were different in different types of mills. This difference between types of mills seemed to originate partly from varying accessibility to production residue that could be used for energy. For all types of mills, variation of electricity prices did not correlate significantly with energy efficiency during the study period. The studied FC were firms age, number of employees, number of companies in company group, net sales and profit for the year. Energy efficiency was more affected by the variables characterizing energy and production compared to the variables representing FC. This study also suggested presence of possible discrepancies between FC that were perceived as barriers to energy management towards energy efficiency, according to previous studies, and what was shown by the data combining variables representing energy use, production and FC. (C) 2018 Elsevier Ltd. All rights reserved.
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| 912. |
- Lawrence, Akvile, 1976-, et al.
(författare)
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Effects of monetary investment, payback time and firm characteristics on electricity saving in energy-intensive industry
- 2019
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Ingår i: Applied Energy. - : Aldring og helse. - 0306-2619 .- 1872-9118. ; 240, s. 499-512
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Tidskriftsartikel (refereegranskat)abstract
- Our study looked at the extent to which firm characteristics such as total firm capital affect electricity saving in energy-intensive industry in Sweden from 2007 to 2015. Specifically, the most influential variables for systematic variation in electricity saving in the energy-intensive companies participating in Sweden’s voluntary programme for improving energy efficiency in energy-intensive industry (the PFE) were studied by analysing monetary investment, payback time and firm characteristics. Monetary investment and payback time influenced electricity savings during the PFE more than firm characteristics, with monetary investment being most influential. Nevertheless, the total systematic variation in firm characteristics may account for ∼16% of the systematic variation in electricity saving, where ∼74% (32 of 43) of the studied firm characteristics seemed to merit further investigation and where ∼49% (21 of 43) of firm characteristics appeared most influential. The most influential firm characteristics were total firm capital, stock turnover ratio, machinery, short-term liabilities per turnover ratio and goodwill. The overall results showed that firm characteristics can influence a firm’s energy-saving activities and indicated a tendency for more energy savings in companies that were financially weaker or had done less work to improve energy efficiency prior to the PFE.
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| 913. |
- Lawrence, Akvile, 1976-
(författare)
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Energy Management for Improved Energy Efficiency in the Pulp and Paper Industry : Success Factors for Strengthening Drivers and Overcoming Barriers
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Industrial energy efficiency improves the profit and competitive advantage of companies. The pulp and paper industry (PPI)being one of the five most energy-intensive industries uses 5.6% of global industrial energy, according to the InternationalEnergy Agency. It is one of the key sectors that is faced with the challenge of improving energy efficiency (EE). The PPI isnot less important in Sweden where it uses approximately 52% of the total industrial energy, employing more than 20000people and where improvement of the energy end-use by 1% corresponds to estimated savings of approximately 218 MSEKannually. Energy management (EnM) is a means for improving EE. However, despite research showing the possibility forannual improvement of the energy end-use by 5.5-19.4% by technical measures, EnM is not always used to its full potentialor often hardly implemented, resulting in an EE gap, i.e. the difference between the theoretical practically and cost-effectivelyachievable EE and actual EE. Why then does this EE gap exist? What are the drivers for and barriers to practicing EnM to itsfull potential and thus improving energy efficiency? What are the success factors for encouraging the drivers and overcomingthe barriers? What practical recommendations can be made that could lead to the improvement of energy efficiency? Afterextracting information from historical and current information using tools from multivariate data analysis (MDA), this PhDdissertation presents new knowledge that intends to contribute to overcome the challenges of improving energy efficiency inthe PPI. Specifically, international research primarily addressing EnM in the PPI showed that EnM in the PPI is perceived asEnM via technology, despite that EnM contains other aspects than EnM via technology, e.g. proactive EnM practices. Thisresult indicates the presence of a knowledge-gap on how to deploy EnM in the PPI. Studies on the PPI in Sweden showeddifferent EnM practices among the individual types of mills, i.e. pulp mills, paper mills and integrated-pulp and paper mills.Integrated mills seemed to measure the energy-related performance more than pulp mills and paper mills. However, the resultsalso suggested that the Swedish PPI worked continuously and regularly with EnM. Further, aside from the top ranked perceiveddrivers being economical and the barriers being organizational, knowledge related drivers and barriers were amongst the mostimportant. The results also showed that commonly only selected employees were trained in EnM, which indicated thatcommunication between the trained employees and operations personnel as well as the absorptive capacity for energy issuescould potentially be improved. Additionally, research showed that by using MDA, previously unstudied and unidentifiedconnections could be discovered. Namely, MDA showed that during the ten-year voluntary agreement policy program knownas PFE (Program for improved electricity efficiency in energy-intensive industry), less financially stable and less experiencedwith EnM companies tended to save electricity more than the more financially stable and more EnM experienced companies.Altogether, the success factors for EnM for improving energy efficiency could be summarized in the versatile 4M memorytool - The “4M for energy efficiency”: mind, measure, monitor and manage. The “4M for energy efficiency” suggests that allthe four “Ms” should be practiced simultaneously in order to maximize the achievement of goals of EnM.
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| 914. |
- Lawrence, Akvile, et al.
(författare)
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Specific Energy Consumption/Use (SEC) in Energy Management for Improving Energy Efficiency in Industry: Meaning, Usage and Differences
- 2019
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Ingår i: Energies. - : MDPI. - 1996-1073. ; 12:2
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Tidskriftsartikel (refereegranskat)abstract
- Although several research studies have adopted specific energy consumption (SEC) as an indicator of the progress of improved energy efficiency, publications are scarce on critical assessments when using SEC. Given the increasing importance of monitoring improved industrial energy efficiency and the rising popularity of SEC as an energy key performance indicator (e-KPI), an in-depth analysis and problematization on the pros and cons of using SEC would appear to be needed. The aim of this article is to analyse SEC critically in relation to industrial energy efficiency. By using SEC in the pulp and paper industry as an example, the results of this exploratory study show that although SEC is often used as an e-KPI in industry, the comparison is not always straightforward. Challenges emanate from a lack of information about how SEC is calculated. It is likely that SEC is an optimal e-KPI within the same study, when all deployed SECs are calculated in the same way, and with the same underlying assumptions. However, before comparing SEC with other studies, it is recommended that the assumptions on which calculations are based should be scrutinized in order to ensure the validity of the comparisons. The paper remains an important contribution in addition to the available handbooks.
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| 915. |
- Lei, Fuchuan, 1987, et al.
(författare)
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Self-injection-locked optical parametric oscillator based on microcombs
- 2024
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Ingår i: Optica. - 2334-2536. ; 11:3, s. 420-426
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Tidskriftsartikel (refereegranskat)abstract
- Narrow-linewidth yet tunable laser oscillators are one of the most important tools for precision metrology, optical atomic clocks, sensing, and quantum computing. Commonly used tunable coherent oscillators are based on stimulated emission or stimulated Brillouin scattering; as a result, the operating wavelength band is limited by the gain media. Based on nonlinear optical gain, optical parametric oscillators (OPOs) enable coherent signal generation within the whole transparency window of the medium used. However, the demonstration of OPO-basedHertz-level linewidth and tunable oscillators has remained elusive. Here, we present a tunable coherent oscillator based on a multimode coherent OPO in a high-Q microresonator, i.e., a microcomb. Single-mode coherent oscillation is realized through self-injection locking (SIL) of one selected comb line. We achieve coarse tuning up to 20 nm and an intrinsic linewidth down to sub- Hertz level, which is three orders of magnitude lower than the pump. Furthermore, we demonstrate that this scheme results in the repetition rate stabilization of the microcomb. These results open exciting possibilities for generating tunable coherent radiation where stimulated emission materials are difficult to obtain, and the stabilization of microcomb sources beyond the limits imposed by the thermorefractive noise in the cavity.
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| 916. |
- Lempesis, Vasileios, et al.
(författare)
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Hand fracture epidemiology and etiology in children - Time trends in Malmö, Sweden, during six decades
- 2019
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Ingår i: Journal of Orthopaedic Surgery and Research. - : Springer Science and Business Media LLC. - 1749-799X. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: The aim of this study was to describe hand fracture epidemiology/etiology in city children and describe time trend during six decades. Patients and methods: A single hospital serves the entire city population of 271,271 (year 2005). Through the hospital medical and radiological archives, we collected epidemiology and etiology data concerning pediatric (age < 16 years) hand fractures in city residents, treated during 2005-2006. We compared these data to previously collected data in in the same city during 12 evaluated periods from 1950/1955 to 1993-1994. We present period-specific crude and age- and gender-adjusted fracture incidence rates and group differences as incidence rate ratios (RR) with 95% confidence intervals (95% CI). Results: In 2005-2006, we identified 414 hand fractures (303 in boys and 111 in girls), 247 phalangeal fractures (60% of all hand fractures), 140 metacarpal/carpal fractures (except the scaphoid bone) (34%), and 27 scaphoid fractures (6%). The crude hand fracture rate in children was 448/100,000 person years (639/100,000 in boys and 247/100,000 in girls), with a 2.5 times higher age-adjusted incidence in boys than in girls. Compared to 1950/1955, the age and gender-adjusted hand fracture incidence was twice as high in 2005-2006 and more than twice as high in 1976-1979. Compared to 1976-1979, we found no significant difference in the age and gender-adjusted hand fracture incidence in 2005-2006. In 2005-2006, sports injuries explained 42%, fights 20%, and traffic accidents 13% of the hand fractures. In 1950/1955, sports injuries explained 27% of fractures, fights 10%, and traffic accidents 21%. Conclusions: The incidence of hand fractures in children was more than twice as high in the end of the 1970s compared to the 1950s, where after no significant change could be found. Also, fracture etiology has changed. New studies are needed, to adequately allocate health care resources and identify new fracture prone activities suitable for preventive measures. Level of evidence: III.
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| 917. |
- Lempesis, Vasileios, et al.
(författare)
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Time trends in pediatric fracture incidence in Sweden during the period 1950–2006
- 2017
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Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 1745-3682. ; 88:4, s. 440-445
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose — Pediatric fracture incidence may not be stable. We describe recent pediatric fracture epidemiology and etiology and compare this to earlier data. Patients and methods — The city of Malmö (population 271,271 in 2005) in Sweden is served by 1 hospital. Using the hospital diagnosis registry, medical charts, and the radiographic archive, we identified fractures in individuals <16 years that had occurred during 2005 and 2006. We also retrieved previously collected fracture data from between 1950 and 1994, from the hospital’s pediatric fracture database. We used official population data to estimate period-specific fracture incidence (the number of fractures per 105 person-years) and also age- and sex-adjusted incidence. Differences are reported as rate ratios (RRs) with 95% confidence intervals. Results — The pediatric fracture incidence during the period 2005–2006 was 1,832 per 105 person-years (2,359 in boys and 1,276 in girls), with an age-adjusted boy-to-girl ratio of 1.8 (1.6–2.1). Compared to the period 1993–1994, age-adjusted rates were unchanged (RR =0.9, 95% CI: 0.8–1.03) in 2005–2006, with lower rates in girls (RR =0.8, 95% CI: 0.7–0.99) but not in boys (RR =1.0, 95% CI: 0.9–1.1). We also found that the previously reported decrease in unadjusted incidence in Malmö from 1976–1979 to 1993–1994 was based on changes in demography, as the age-adjusted incidences were similar in the 2 periods (RR =1.0, 95% CI: 0.9–1.1). Interpretation — In Malmö, pediatric fracture incidence decreased from 1993–1994 to 2005–2006 in girls but not in boys. Changes in demography, and also other factors, influence the recent time trends.
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| 918. |
|
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| 919. |
- Lengyel, Tamas, 1986, et al.
(författare)
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Impact of Damping on 50 Gbps 4-PAM Modulation of 25G Class VCSELs
- 2017
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Ingår i: Optics InfoBase Conference Papers. - 2162-2701. - 9781943580231 ; , s. paper W3G.2-
-
Konferensbidrag (refereegranskat)abstract
- We investigate the effects of photon lifetime and damping of the modulation response on the quality of 50 Gbps 4-PAM signal generation with directly modulated 25G class VCSELs and identify the appropriate values for the K-factor.
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| 920. |
- Lengyel, Tamas, 1986, et al.
(författare)
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Impact of Damping on 50 Gbps 4-PAM Modulation of 25G Class VCSELs
- 2017
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Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 35:19, s. 4203-4209
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Tidskriftsartikel (refereegranskat)abstract
- We present an investigation into the effects of photon lifetime and the associated damping of the modulation response on 50 Gbps 4-PAM signal generation with directly modulated 25G class VCSELs. While 4-PAM benefits from higher slope efficiency and output power, it is shown that the greater impact of intensity noise and dynamic nonlinearities implies that a VCSEL with a longer photon lifetime and more damped response is needed when transitioning from existing 25 Gbps OOK to 50 Gbps 4-PAM using the 25G VCSEL technology.
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