Velocity ratio-cum-transfer matrix method for the evaluation of a muffler with mean flow

The paper deals with a method for the evaluation of exhaust muffers with mean flow. A new set of variables, convective pressure and convective mass velocity, have been defined to replace the acoustic variables. An expression for attenuation (insertion loss) of a muffler has been proposed in terms of convective terminal impedances and a velocity ratio, on the lines of the one existing for acoustic filters. In order to evaluate the velocity ratio in terms of convective variables, transfer matrices for various muffler elements have been derived from the basic relations of energy, mass and momentum. Finally, the velocity ratiocum-transfer matrix method is illustrated for a typical straight-through muffler.

Mean Flow Measurements in Turbulent Boundary Layers along Mildly Curved Surfaces

An experimental investigation of the mean flow characteristics of two-dimensional turbulent boundary layers over surfaces of mild longitudinal curvature is reported. The study covered both convex and concave walls of \d/Rw I « 0.013 (d being the boundary-layer thickness and Rw being the wall radius). It was found that, whereas the region close to the wall was not affected significantly by wall curvature, the outer region was very sensitive to even mild wall curvature. A detailed study of the wake region using present and other available data suggests a systematic effect of b/Rw on the wake structure. The paper also discusses in detail the effect of mild wall curvature on the boundary-layer development with particular emphasis on the difference in behavior of the boundary layer at short and long distances from the leading edge of the curved wall, an aspect which has not received sufficient attention in previous experimental investigations. An attempt has been made to explain this behavior from a consideration of the structure of turbulence in boundary layers over curved surfaces taken into account.

Method for evaluation of the acoustical impedance of a black box, with or without mean flow, measuring pressures at fixed positions

The transmission-line or the impedance-tube method for the measurement of the acoustic impedance of any termination involves a search for various minima and maxima of pressure. For this purpose, arrangement has to be made for the microphone to travel along the length of the impedance tube, and this complicates the design of the tube considerably. The present paper discusses a method which consists in evaluating the tube attenuation factor at any convenient frequency by making use of measured SPL's at two (or more) fixed locations with a rigid termination, calculating the tube attenuation factor and wave number at the required frequency of interest with or without mean flow (as applicable), and finally evaluating the impedance of the given termination by measuring and using SPL's at three (or more) fixed locations. Thus, the required impedance tube is considerably smaller in length, simpler in design, easier to manufacture, cheaper in cost and more convenient to use. The design of the tube is also discussed. Incidentally, it is also possible to evaluate the impedance at any low frequency without having to use a larger impedance tube.

Incorporating the interrelationship between primary and support processes in monitoring and optimising longwall coal mining efficiency

This thesis increased the researchers understanding of the relationship between operations and maintenance in underground longwall coal mines, using data from a Queensland underground coal mine. The thesis explores various relationships between recorded variables. Issues with human recorded data was uncovered, and results emphasised the significance of variables associated with conveyor operation to explain production.

Predictive technology and natural hazards: Risk for Australian planning authorities?

Purpose The object of this paper is to examine whether the improvements in technology that enhance community understanding of the frequency and severity of natural hazards also increased the risk of potential liability of planning authorities in negligence. In Australia, the National Strategy imposes a resilience based approach to disaster management and stresses that responsible land use planning can reduce or prevent the impact of natural hazards upon communities. Design/methodology/approach This paper analyses how the principles of negligence allocate responsibility for loss suffered by a landowner in a hazard prone area between the landowner and local government. Findings The analysis in this paper concludes that despite being able to establish a causal link between the loss suffered by a landowner and the approval of a local authority to build in a hazard prone area, it would be in the rarest of circumstances a negligence action may be proven. Research limitations/implications The focus of this paper is on planning policies and land development, not on the negligent provision of advice or information by the local authority. Practical implications This paper identifies the issues a landowner may face when seeking compensation from a local authority for loss suffered due to the occurrence of a natural hazard known or predicted to be possible in the area. Originality/value The paper establishes that as risk managers, local authorities must place reliance upon scientific modelling and predictive technology when determining planning processes in order to fulfil their responsibilities under the National Strategy and to limit any possible liability in negligence.

On plane-wave propagation in a uniform pipe in the presence of a mean flow and a temperature gradient

A theoretical study on the propagation of plane waves in the presence of a hot mean flow in a uniform pipe is presented. The temperature variation in the pipe is taken to be a linear temperature gradient along the axis. The theoretical studies include the formulation of a wave equation based on continuity, momentum, and state equation, and derivation of a general four-pole matrix, which is shown to yield the well-known transfer matrices for several other simpler cases.

U12-type Spliceosome: Localization and Effects of Splicing Efficiency on Gene Expression

The removal of non-coding sequences, introns, is an essential part of messenger RNA processing. In most metazoan organisms, the U12-type spliceosome processes a subset of introns containing highly conserved recognition sequences. U12-type introns constitute less than 0,5% of all introns and reside preferentially in genes related to information processing functions, as opposed to genes encoding for metabolic enzymes. It has previously been shown that the excision of U12-type introns is inefficient compared to that of U2-type introns, supporting the model that these introns could provide a rate-limiting control for gene expression. The low efficiency of U12-type splicing is believed to have important consequences to gene expression by limiting the production of mature mRNAs from genes containing U12-type introns. The inefficiency of U12-type splicing has been attributed to the low abundance of the components of the U12-type spliceosome in cells, but this hypothesis has not been proven. The aim of the first part of this work was to study the effect of the abundance of the spliceosomal snRNA components on splicing. Cells with a low abundance of the U12-type spliceosome were found to inefficiently process U12-type introns encoded by a transfected construct, but the expression levels of endogenous genes were not found to be affected by the abundance of the U12-type spliceosome. However, significant levels of endogenous unspliced U12-type intron-containing pre-mRNAs were detected in cells. Together these results support the idea that U12-type splicing may limit gene expression in some situations. The inefficiency of U12-type splicing has also promoted the idea that the U12-type spliceosome may control gene expression, limiting the mRNA levels of some U12-type intron-containing genes. While the identities of the primary target genes that contain U12-type introns are relatively well known, little has previously been known about the downstream genes and pathways potentially affected by the efficiency of U12-type intron processing. Here, the effects of U12-type splicing efficiency on a whole organism were studied in a Drosophila line with a mutation in an essential U12-type spliceosome component. Genes containing U12-type introns showed variable gene-specific responses to the splicing defect, which points to variation in the susceptibility of different genes to changes in splicing efficiency. Surprisingly, microarray screening revealed that metabolic genes were enriched among downstream effects, and that the phenotype could largely be attributed to one U12-type intron-containing mitochondrial gene. Gene expression control by the U12-type spliceosome could thus have widespread effects on metabolic functions in the organism. The subcellular localization of the U12-type spliceosome components was studied as a response to a recent dispute on the localization of the U12-type spliceosome. All components studied were found to be nuclear indicating that the processing of U12-type introns occurs within the nucleus, thus clarifying a question central to the field. The results suggest that the U12-type spliceosome can limit the expression of genes that contain U12-type introns in a gene-specific manner. Through its limiting role in pre-mRNA processing, the U12-type splicing activity can affect specific genetic pathways, which in the case of Drosophila are involved in metabolic functions.

Measuring tax efficiency: A tax optimality index

This paper introduces an index of tax optimality that measures the distance of some current tax structure from the optimal tax structure in the presence of public goods. This index is defined on the [0, 1] interval and measures the proportion of the optimal tax rates that will achieve the same welfare outcome as some arbitrarily given initial tax structure. We call this number the Tax Optimality Index. We also show how the basic methodology can be altered to derive a revenue equivalent uniform tax, which measures the tax burden implied by the public sector. A numerical example is used to illustrate the method developed, and extensions of the analysis to handle models with multiple households and nonlinear taxation structures are undertaken.

Country-scale carbon accounting of the vegetation and mineral soils of Finland

The increase in global temperature has been attributed to increased atmospheric concentrations of greenhouse gases (GHG), mainly that of CO2. The threat of severe and complex socio-economic and ecological implications of climate change have initiated an international process that aims to reduce emissions, to increase C sinks, and to protect existing C reservoirs. The famous Kyoto protocol is an offspring of this process. The Kyoto protocol and its accords state that signatory countries need to monitor their forest C pools, and to follow the guidelines set by the IPCC in the preparation, reporting and quality assessment of the C pool change estimates. The aims of this thesis were i) to estimate the changes in carbon stocks vegetation and soil in the forests in Finnish forests from 1922 to 2004, ii) to evaluate the applied methodology by using empirical data, iii) to assess the reliability of the estimates by means of uncertainty analysis, iv) to assess the effect of forest C sinks on the reliability of the entire national GHG inventory, and finally, v) to present an application of model-based stratification to a large-scale sampling design of soil C stock changes. The applied methodology builds on the forest inventory measured data (or modelled stand data), and uses statistical modelling to predict biomasses and litter productions, as well as a dynamic soil C model to predict the decomposition of litter. The mean vegetation C sink of Finnish forests from 1922 to 2004 was 3.3 Tg C a-1, and in soil was 0.7 Tg C a-1. Soil is slowly accumulating C as a consequence of increased growing stock and unsaturated soil C stocks in relation to current detritus input to soil that is higher than in the beginning of the period. Annual estimates of vegetation and soil C stock changes fluctuated considerably during the period, were frequently opposite (e.g. vegetation was a sink but soil was a source). The inclusion of vegetation sinks into the national GHG inventory of 2003 increased its uncertainty from between -4% and 9% to ± 19% (95% CI), and further inclusion of upland mineral soils increased it to ± 24%. The uncertainties of annual sinks can be reduced most efficiently by concentrating on the quality of the model input data. Despite the decreased precision of the national GHG inventory, the inclusion of uncertain sinks improves its accuracy due to the larger sectoral coverage of the inventory. If the national soil sink estimates were prepared by repeated soil sampling of model-stratified sample plots, the uncertainties would be accounted for in the stratum formation and sample allocation. Otherwise, the increases of sampling efficiency by stratification remain smaller. The highly variable and frequently opposite annual changes in ecosystem C pools imply the importance of full ecosystem C accounting. If forest C sink estimates will be used in practice average sink estimates seem a more reasonable basis than the annual estimates. This is due to the fact that annual forest sinks vary considerably and annual estimates are uncertain, and they have severe consequences for the reliability of the total national GHG balance. The estimation of average sinks should still be based on annual or even more frequent data due to the non-linear decomposition process that is influenced by the annual climate. The methodology used in this study to predict forest C sinks can be transferred to other countries with some modifications. The ultimate verification of sink estimates should be based on comparison to empirical data, in which case the model-based stratification presented in this study can serve to improve the efficiency of the sampling design.

Laboratory analyses for evaluation of platelet disorders and platelet concentrates

High quality of platelet analytics requires specialized knowledge and skills. It was applied to analyze platelet activation and aggregation responses in a prospective controlled study of patients with Finnish type of amyloidosis. The 20 patients with AGel amyloidosis displayed a delayed and more profound platelet shape change than healthy siblings and healthy volunteers, which may be related to altered fragmentation of mutated gelsolin during platelet activation. Alterations in platelet shape change have not been reported in association with platelet disorders. In the rare Bernard-Soulier syndrome with Asn45Ser mutation of glycoprotein (GP) IX, the diagnostic defect in the expression of GPIb-IX-V complex was characterized in seven Finnish patients, also an internationally exceptionally large patient series. When measuring thrombopoietin in serial samples of amniotic fluid and cord blood of 15 pregnant women with confirmed or suspected fetal alloimmune thrombocytopenia, the lower limit of detection could be extended. The results approved that thrombopoietin is present already in amniotic fluid. The application of various non-invasive means for diagnosing thrombocytopenia (TP) revealed that techniques for estimating the proportion of young, i.e. large platelets, such as direct measurement of reticulated platelets and the mean platelet size, would be useful for evaluating platelet kinetics in a given patient. Due to different kinetics between thrombopoietin and increase of young platelets in circulation, these measurements may have most predictive value when measured from simultaneous samples. Platelet autoantibodies were present not only in isolated autoimmune TP but also in patients without TP where disappearance of platelets might be compensated by increased production. The autoantibodies may also persist after TP has been cured. Simultaneous demonstration of increased young platelets (or increased mean platelet volume) in peripheral blood and the presence of platelet associated IgG specificities to major glycoproteins (GPIb-IX and GPIIb-IIIa) may be considered diagnostic for autoimmune TP. Measurement of a soluble marker as a sign of thrombin activation and proceeding deterioration of platelet components was applied to analyze the alterations under several stress factors (storage, transportation and lack of continuous shaking under controlled conditions) of platelet products. The GPV measured as a soluble factor in platelet storage medium showed good correlation with an array of other measurements commonly applied in characterization of stored platelets. The benefits of measuring soluble analyte in a quantitative assay were evident.

Kohti leikkaussalin tuloksellista toiminnanohjausta

Background: The aging population is placing increasing demands on surgical services, simultaneously with a decreasing supply of professional labor and a worsening economic situation. Under growing financial constraints, successful operating room management will be one of the key issues in the struggle for technical efficiency. This study focused on several issues affecting operating room efficiency. Materials and methods: The current formal operating room management in Finland and the use of performance metrics and information systems used to support this management were explored using a postal survey. We also studied the feasibility of a wireless patient tracking system as a tool for managing the process. The reliability of the system as well as the accuracy and precision of its automatically recorded time stamps were analyzed. The benefits of a separate anesthesia induction room in a prospective setting were compared with the traditional way of working, where anesthesia is induced in the operating room. Using computer simulation, several models of parallel processing for the operating room were compared with the traditional model with respect to cost-efficiency. Moreover, international differences in operating room times for two common procedures, laparoscopic cholecystectomy and open lung lobectomy, were investigated. Results: The managerial structure of Finnish operating units was not clearly defined. Operating room management information systems were found to be out-of-date, offering little support to online evaluation of the care process. Only about half of the information systems provided information in real time. Operating room performance was most often measured by the number of procedures in a time unit, operating room utilization, and turnover time. The wireless patient tracking system was found to be feasible for hospital use. Automatic documentation of the system facilitated patient flow management by increasing process transparency via more available and accurate data, while lessening work for staff. Any parallel work flow model was more cost-efficient than the traditional way of performing anesthesia induction in the operating room. Mean operating times for two common procedures differed by 50% among eight hospitals in different countries. Conclusions: The structure of daily operative management of an operating room warrants redefinition. Performance measures as well as information systems require updating. Parallel work flows are more cost-efficient than the traditional induction-in-room model.

Outcomes of ruptured abdominal aortic aneurysm

Ruptured abdominal aortic aneurysm (RAAA) is a life-threatening event, and without operative treatment the patient will die. The overall mortality can be as high as 80-90%; thus repair of RAAA should be attempted whenever feasible. The quality of life (QoL) has become an increasingly important outcome measure in vascular surgery. Aim of the study was to evaluate outcomes of RAAA and to find out predictors of mortality. In Helsinki and Uusimaa district 626 patients were identified to have RAAA in 1996-2004. Altogether 352 of them were admitted to Helsinki University Central Hospital (HUCH). Based on Finnvasc Registry, 836 RAAA patients underwent repair of RAAA in 1991-1999. The 30-day operative mortality, hospital and population-based mortality were assessed, and the effect of regional centralisation and improving in-hospital quality on the outcome of RAAA. QoL was evaluated by a RAND-36 questionnaire of survivors of RAAA. Quality-adjusted life years (QALYs), which measure length and QoL, were calculated using the EQ-5D index and estimation of life expectancy. The predictors of outcome after RAAA were assessed at admission and 48 hours after repair of RAAA. The 30-day operative mortality rate was 38% in HUCH and 44% nationwide, whereas the hospital mortality was 45% in HUCH. Population-based mortality was 69% in 1996-2004 and 56% in 2003-2004. After organisational changes were undertaken, the mortality decreased significantly at all levels. Among the survivors, the QoL was almost equal when compared with norms of age- and sex-matched controls; only physical functioning was slightly impaired. Successful repair of RAAA gave a mean of 4.1 (0-30.9) QALYs for all RAAA patients, although non-survivors were included. The preoperative Glasgow Aneurysm Score was an independent predictor of 30-day operative mortality after RAAA, and it also predicted the outcome at 48- hours for initial survivors of repair of RAAA. A high Glasgow Aneurysm Score and high age were associated with low numbers of QALYs to be achieved. Organ dysfunction measured by the Sequential Organ Failure Assessment (SOFA) score at 48 hours after repair of RAAA was the strongest predictor of death. In conclusion surgery of RAAA is a life-saving and cost-effective procedure. The centralisation of vascular emergencies improved the outcome of RAAA patients. The survivors had a good QoL after RAAA. Predictive models can be used on individual level only to provide supplementary information for clinical decision-making due to their moderate discriminatory value. These results support an active operation policy, as there is no reliable measure to predict the outcome after RAAA.

Spatial and vertical heterogeneities in aerosol properties over oceanic regions around India: Implications for radiative forcing

The influence of atmospheric aerosols on Earth's radiation budget and hence climate, though well recognized and extensively investigated in recent years, remains largely uncertain mainly because of the large spatio-temporal heterogeneity and the lack of data with adequate resolution. To characterize this diversity, a major multi-platform field campaign ICARB (Integrated Campaign for Aerosols, gases and Radiation Budget) was carried out during the pre-monsoon period of 2006 over the Indian landmass and surrounding oceans, which was the biggest such campaign ever conducted over this region. Based on the extensive and concurrent measurements of the optical and physical properties of atmospheric aerosols during ICARB, the spatial distribution of aerosol radiative forcing was estimated over the entire Bay of Bengal (BoB), northern Indian Ocean and Arabian Sea (AS) as well as large spatial variations within these regions. Besides being considerably lower than the mean values reported earlier for this region, our studies have revealed large differences in the forcing components between the BoB and the AS. While the regionally averaged aerosol-induced atmospheric forcing efficiency was 31 +/- 6 W m(-2) tau(-1) for the BoB, it was only similar to 18 +/- 7 W m(-2) tau(-1) for the AS. Airborne measurements revealed the presence of strong, elevated aerosol layers even over the oceans, leading to vertical structures in the atmospheric forcing, resulting in significant warming in the lower troposphere. These observations suggest serious climate implications and raise issues ranging from the impact of aerosols on vertical thermal structure of the atmospheric and hence cloud formation processes to monsoon circulation.

Outcome of singleton pregnancy after assisted reproductive treatment

Singleton pregnancies achieved by means of assisted reproductive treatment (ART) are associated with increased obstetric and neonatal risks in comparison with spontaneously conceived singleton pregnancies. The impact of infertility- and treatment-related factors on these risks is not properly understood. In addition, the psychological effects of infertility and its treatment on the experience of pregnancy have scarcely been studied. Thus, the aim of the present study was to evaluate the importance of infertility- and treatment-related factors on prediction of pregnancy outcome, obstetric and neonatal risks, fear-of-childbirth and pregnancy-related anxiety. The subjects consisted of infertile women who achieved a singleton pregnancy by means of in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI). The control groups comprised spontaneously conceiving women with singleton gestations. Early pregnancy outcome was assessed by means of assay of serum human chorionic gonadoptrophin (hCG) in single samples. Other outcome data were collected from patient records, national Health Registers and via prospective questionnaire surveys. Viable pregnancies were associated with significantly higher serum hCG levels 12 days after embryo transfer than non-viable pregnancies. Among singleton pregnancies, aetiological subgroup, treatment type or the number of transferred embryos did not impair the predictive value of single hCG assessment. According to the register-based data, age-, parity- and socioeconomic status- adjusted risks of gestational hypertension, preterm contractions and placenta praevia were more frequent in the ART pregnancies than in the control pregnancies. Significantly higher rates of induction of delivery and Caesarean section occurred in the ART group than in the control group. The risks of preterm birth and low birth weight (LBW) were increased after ART pregnancy. Duration or aetiology of infertility, treatment type (fresh or frozen IVF or ICSI) or rank of treatment did not contribute to the risks of preterm birth or LBW. In addition, the risks of preterm birth and LBW remained elevated in spite of of the number of transferred embryos. Although mean duration of pregnancy was shorter and mean birth weight lower in the ART pregnancies than in the control pregnancies, these differences were hardly of clinical significance. Fear-of-childbirth and pregnancy-related anxiety were equally common to women conceiving by means of ART, or spontaneously. Partnership of five to ten years appeared to be protective as regards severe fear-of-childbirth, whereas long preceding infertility (≥ seven years) had the opposite effect. In conclusion, an early hCG assessment maintained its good predictive value regardless of infertility- or patient-related factors. Further, we did not recognise any infertility- or patient-related factors that would expose infertile women to increased obstetric or neonatal risks. However, a long period of infertility was associated with severe fear-of-childbirth.

The incidence and outcome of severe sepsis in Finland : The Finnsepsis Study

Severe sepsis is associated with common occurrence, high costs of care and significant mortality. The incidence of severe sepsis has been reported to vary between 0.5/1000 and 3/1000 in different studies. The worldwide Severe Sepsis Campaign, guidelines and treatment protocols aim at decreasing severe sepsis associated high morbidity and mortality. Various mediators of inflammation, such as high mobility group box-1 protein (HMGB1) and vascular endothelial growth factor (VEGF), have been tested for severity of illness and outcome in severe sepsis. Long-term survival with quality of life (QOL) assessment is important outcome after severe sepsis. The objective of this study was to evaluate the incidence, severity of organ dysfunction and outcome of severe sepsis in intensive care treated patients in Finland (study I)). HMGB1 and VEGF were studied in predicting severity of illness, development and type of organ dysfunction and hospital mortality (studies II and III). The long-term outcome and quality of life were assessed and quality-adjusted life years and cost per one QALY were estimated (study IV). A total of 470 patients with severe sepsis were included in the Finnsepsis Study. Patients were treated in 24 Finnish intensive care units in a 4-month period from 1 November 2004 to 28 February 2005. The incidence of severe sepsis was 0.38 /1,000 in the adult population (95% confidence interval 0.34-0.41). Septic shock (77%), severe oxygenation impairment (71.4%) and acute renal failure (23.2%) were the most common organ failures. The ICU, hospital, one-year and two-year mortalities were 15.5%, 28.3%, 40.9% and 44.9% respectively. HMGB1 and VEGF were elevated in patients with severe sepsis. VEGF concentrations were lower in non-survivors than in survivors, but HMGB1 levels did not differ between patients. Neither HMGB1 nor VEGF were predictive of hospital mortality. The QOL was measured median 17 months after severe sepsis and QOL was lower than in reference population. The mean QALY was 15.2 years for a surviving patient and the cost for one QALY was 2,139 . The study showed that the incidence of severe sepsis is lower in Finland than in other countries. The short-term outcome is comparable with that in other countries, but long-term outcome is poor. HMGB1 and VEGF are not useful in predicting mortality in severe sepsis. The mean QALY for a surviving patient is 15.2 and as the cost for one QALY is reasonably low, the intensive care is cost-effective in patients with severe sepsis.