Work Conditions and Practices in Norwegian Fire Departments From 1950 Until Today: A Survey on Factors Potentially Influencing Carcinogen Exposure

Jakobsen, Jarle,Babigumira, Ronnie,Danielsen, Marie,Grimsrud, Tom K.,Olsen, Raymond,Rosting, Cecilie,Veierod, Marit B.,Kjaerheim, Kristina Occupational Safety and Health Research Institute 2020 Safety and health at work Vol.11 No.4

Background: Meta-analyses have shown firefighters to be at an increased risk of several cancer types. Occupational carcinogen exposure may explain these increased risks. This study aims to describe Norwegian fire departments' work conditions from 1950 until today, focusing on factors relevant for potential occupational carcinogen exposure. Methods: With the help of a reference group, we developed a questionnaire on topics related to occupational exposure to carcinogens for the period 1950-2018. Selected Norwegian fire departments provided department-specific responses. Results: Sixteen departments, providing fire services for 48% of the Norwegian population as of 2019 and mainly consisting of professional firefighters, responded to our questionnaire. The introduction of synthetic firefighting foams, more regular live fire training, the introduction of chemical diving, and a higher number of diesel-driven fire service vehicles were identified as changes thought to increase exposure to occupational carcinogens. Changes thought to decrease exposure included the switch from negative to positive pressure self-contained breathing apparatuses, the use of self-contained breathing apparatuses during all phases of firefighting, the use of ventilating fans during firefighting, increased attention to flammable materials used during live fire training, increased attention to handling and cleaning of turnout gear and other equipment, and installment of exhaust removal systems in apparatus bays. Conclusion: Norwegian fire departments' work conditions have seen several changes since 1950, and this could influence firefighters' occupational carcinogen exposure. A peak of carcinogen exposure may have occurred in the 1970s and 1980s before recent changes have reduced exposure.

Sensorless Control of Low-Cost Single-Phase Hybrid Switched Reluctance Motor Drive

Jakobsen, Uffe,Kaiyuan Lu,Rasmussen, Peter Omand,Dong-Hee Lee,Jin-Woo Ahn IEEE 2015 IEEE transactions on industry applications Vol.51 No.3

<P>This paper presents a sensorless-controlled, low-cost, low-power, and variable-speed drive system suitable for fan and pump applications. The main advantages of this drive system are the low system cost, simple converter structure, and simple but robust sensorless control technique. The drive motor is a special hybrid switched reluctance motor. The proposed sensorless control method beneficially utilizes the stator side PM field and its performance is motor parameter independent. The unique low-cost drive system solution, simple and robust sensorless control features of this drive system, is demonstrated in detail in this paper. Important design details for practical implementation of the sensorless control algorithm are included. The complete drive system performance is validated using a prototype drive system.</P>

Custom Processor for AC Motor Control implemented in Spartan 3E FPGA

Uffe Jakobsen,안진우(Jin-Woo Ahn) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.10

Motor control for small series some-times requires specialized control logic, requiring rewiring if new logic needs to be added. This paper describes a different approach to hardware and software co-design, namely designing a 32 bit softcore processor with an instruction set to fit the purpose of control of drives.. The designer can then choose between resource usage on the FPGA and speed in new ways. The approach is tested for two different motor types, synchronous and hybrid switched reluctance motors, using a Spartan 3E FPGA. The instruction set allows for higher code density than Texas MSP430 and Texas TMS320F2812 for field oriented control.

Service Experience of MAN B&W Two Stroke Diesel Engines

Stig Jakobsen 한국마린엔지니어링학회 2010 한국마린엔지니어링학회 학술대회 논문집 Vol.2010 No.10

Geographical and temporal patterns of interstate security competition: Global and regional evidence

Jo Jakobsen,Thomas Halvorsen 한국외국어대학교 국제지역연구센터 2019 International Area Studies Review Vol.22 No.3

This article tests what seems to be a reasonably widespread perception, namely, that the last few years have witnessed intensified interstate security competition in several of the world’s regions. Specifically, we investigate whether or not states’ military budgets tend to change as a function of changes to the armaments levels of neighbouring states, as the security dilemma model would suggest. We perform two empirical analyses. First, we specify a least square dummy variables model, whose results we map using standard geographic information system software. Our ‘hot spot’ analysis for the period 2008/2009–2014 suggests that action–reaction dynamics are present in the Middle East, Central and Southern Africa, and the South Caucasus. Neither South nor East or South East Asia is ridden by severe security competition. Europe generally forms a ‘cold spot’ region, indicating a lower-than-expected level of changes in arms spending. Second, our spatial lag model suggests the presence of action–reaction globally for the whole post-Cold War era, although results are still substantially driven by the last few years. Interstate security competition is now, apparently, an important element of international politics – albeit only in some regions. Our findings also reveal the potential for disarmament spirals.

Expression analyses of human cleft palate tissue suggest a role for osteopontin and immune related factors in palatal development

Linda P. Jakobsen,Rehannah Borup,Janni Vestergaard,Lars A. Larsen,Kasper Lage,Lisa Leth Maroun,Inger Kjaer,Carsten U. Niemann,Mikael Andersen,Mary A. Knudsen,Kjeld Møllgård,Niels Tommerup 생화학분자생물학회 2009 Experimental and molecular medicine Vol.41 No.2

Cleft lip and/or palate (CL/P) is a common congenital malformation with a complex etiology which is not fully elucidated yet. Epidemiological studies point to different etiologies in the cleft lip and palate subgroups, isolated cleft lip (CL), isolated cleft palate (CP) and combined cleft lip and palate (CLP). In order to understand the biological basis in these cleft lip and palate subgroups better we studied the expression profiles in human tissue from patients with CL/P. In each of the CL/P subgroups, samples were obtained from three patients and gene expression analysis was performed. Moreover, selected differentially expressed genes were analyzed by quantitative RT-PCR, and by immunohistochemical staining of craniofacial tissue from human embryos. Osteopontin (SPP1) and other immune related genes were significantly higher expressed in palate tissue from patients with CLP compared to CP and immunostaining in palatal shelves against SPP1, chemokine receptor 4 (CXCR4) and serglycin (PRG1) in human embryonic craniofacial tissue were positive, supporting a role for these genes in palatal development. However, gene expression profiles are subject to variations during growth and therefore we recommend that future gene expression in CL/P studies should use tissue from the correct embryonic time and place if possible, to overcome the biases in the presented study. Cleft lip and/or palate (CL/P) is a common congenital malformation with a complex etiology which is not fully elucidated yet. Epidemiological studies point to different etiologies in the cleft lip and palate subgroups, isolated cleft lip (CL), isolated cleft palate (CP) and combined cleft lip and palate (CLP). In order to understand the biological basis in these cleft lip and palate subgroups better we studied the expression profiles in human tissue from patients with CL/P. In each of the CL/P subgroups, samples were obtained from three patients and gene expression analysis was performed. Moreover, selected differentially expressed genes were analyzed by quantitative RT-PCR, and by immunohistochemical staining of craniofacial tissue from human embryos. Osteopontin (SPP1) and other immune related genes were significantly higher expressed in palate tissue from patients with CLP compared to CP and immunostaining in palatal shelves against SPP1, chemokine receptor 4 (CXCR4) and serglycin (PRG1) in human embryonic craniofacial tissue were positive, supporting a role for these genes in palatal development. However, gene expression profiles are subject to variations during growth and therefore we recommend that future gene expression in CL/P studies should use tissue from the correct embryonic time and place if possible, to overcome the biases in the presented study.

Two-Phase Interleaved Buck Converter with a new Digital Self-Oscillating Modulator

Lars T. Jakobsen,Michael A. E. Andersen 전력전자학회 2007 ICPE(ISPE)논문집 Vol.- No.-

This paper presents a new Digital Self-Oscillating Modulator (DiSOM) for DC/DC converters. The DiSOM modulator alllows the digital control algorithm to sample the output voltage at a sampling frequency higher than the converter switching frequency. This enables higher control loop bandwidth than for traditional digital PWM modulators given a certain switching frequency. A synchronised version of the DiSOM modulator is derived for interleaved converters. A prototype interleaved Buck converter for Point of Load applications has been designed and built to test the performance of DiSOM modulator. The DiSOM modulator and a digital control algorithm have been implemented in an FPGA. Experimental results show that the converter has a very fast transient response when a loadstep is applied to the output. For a loadstep of 50% of nominal output current the output voltage overshoot is less than 2.5% of the nominal output voltage and the settling time is just 8 switching periods.

Synthesis of covalent organic polymers for removing heavy metal ions with strong affinity

Dongah Ko,Mogens H. Jakobsen,Yuhoon Hwang,Cafer T. Yavuz,Henrik R. Andersen 대한환경공학회 2015 대한환경공학회 학술발표논문집 Vol.2015 No.10

Disulfide polymer grafted porous carbon composites for heavy metal removal from stormwater runoff

Ko, Dongah,Mines, Paul D.,Jakobsen, Mogens H.,Yavuz, Cafer T.,Hansen, Hans Chr. B.,Andersen, Henrik R. Elsevier 2018 Chemical engineering journal Vol.348 No.-

<P><B>Abstract</B></P> <P>The emerging concern of heavy metal pollution derived from stormwater runoff has triggered a demand for effective heavy metal sorbents. To be an effective sorbent, high affinity along with rapid sorption kinetics for environmental relevant concentrations of heavy metals is important. Herein, we have introduced a new composite suitable for trace metal concentration removal, which consists of cheap and common granular activated carbon covered with polymers containing soft bases, thiols, through acyl chlorination (DiS-AC). Material characterization demonstrated that the polymer was successfully grafted and grown onto the surface of the carbon substrate. The distribution coefficient for Cd<SUP>2+</SUP> bonding was 89·10<SUP>3</SUP> L/kg at a solution concentration of 0.35 mg/L, which is notably higher than sorption affinities for Cd<SUP>2+</SUP> seen in conventional sorbents. The sorption isotherm is well described by the Freundlich isotherm and within an hour, half of the initial trace (0.2 mg/L) concentration of Cd<SUP>2+</SUP> was removed by the DiS-AC at a sorbent loading of 2 g/L. Therefore, the novel material DiS-AC promises to be an ideal candidate for filters treating stormwater runoff.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The novel disulfide polymer grafted activated carbon composites were devised. </LI> <LI> Covalent bonds between disulfide polymer and carbon substrate have been proven. </LI> <LI> DiS-AC showed rapid kinetics on removing heavy metal in overall range of pH 6–8. </LI> <LI> DiS-AC showed high affinity towards even for trace amount of heavy metal in water. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Identification of flutter derivatives from full-scale ambient vibration measurements of the Clifton Suspension Bridge

Nikitas, Nikolaos,Macdonald, John H.G.,Jakobsen, Jasna B. Techno-Press 2011 Wind and Structures, An International Journal (WAS Vol.14 No.3

The estimated response of large-scale engineering structures to severe wind loads is prone to modelling uncertainties that can only ultimately be assessed by full-scale testing. To this end ambient vibration data from full-scale monitoring of the historic Clifton Suspension Bridge has been analysed using a combination of a frequency domain system identification method and a more elaborate stochastic identification technique. There is evidence of incipient coupling action between the first vertical and torsional modes in strong winds, providing unique full-scale data and making this an interesting case study. Flutter derivative estimation, which has rarely previously been attempted on full-scale data, was performed to provide deeper insight into the bridge aerodynamic behaviour, identifying trends towards flutter at higher wind speeds. It is shown that, as for other early suspension bridges with bluff cross-sections, single-degree-of-freedom flutter could potentially occur at wind speeds somewhat below requirements for modern designs. The analysis also demonstrates the viability of system identification techniques for extracting valuable results from full-scale data.