IMPROVING STARTABILITY AND REDUCING EMISSIONS IN FLEXFUEL SPARK IGNITION DIRECT INJECTION VARIABLE CAM TIMING ENGINE

Experimental work and analysis was done to investigate engine startup robustness and emissions of a flex-fuel spark ignition (SI) direct injection (DI) engine. The vaporization and other characteristics of ethanol fuel blends present a challenge at engine startup. Strategies to reduce the enrichment requirements for the first engine startup cycle and emissions for the second and third fired cycle at 25°C ± 1°C engine and intake air temperature were investigated. Research work was conducted on a single cylinder SIDI engine with gasoline and E85 fuels, to study the effect on first fired cycle of engine startup. Piston configurations that included a compression ratio change (11 vs 15.5) and piston geometry change (flattop vs bowl) were tested, along with changes in intake cam timing (95,110,125) and fuel pressure (0.4 MPa vs 3 MPa). The goal was to replicate the engine speed, manifold pressure, fuel pressure and testing temperature from an engine startup trace for investigating the first fired cycle for the engine. Results showed bowl piston was able to enable lower equivalence ratio engine starts with gasoline fuel, while also showing lower IMEP at the same equivalence ratio compared to flat top piston. With E85, bowl piston showed reduced IMEP as compression ratio increased at the same equivalence ratio. A preference for constant intake valve timing across fuels seemed to indicate that flattop piston might be a good flex-fuel piston. Significant improvements were seen with higher CR bowl piston with high fuel pressure starts, but showed no improvement with low fuel pressures. Simulation work was conducted to analyze initial three cycles of engine startup in GT-POWER for the same set of hardware used in the experimentations. A steady state validated model was modified for startup conditions. The results of which allowed an understanding of the relative residual levels and IMEP at the test points in the cam phasing space. This allowed selecting additional test points that enable use of higher residual levels, eliminating those with smaller trapped mass incapable of producing required IMEP for proper engine turnover. The second phase of experimental testing results for 2nd and 3rd startup cycle revealed both E10 and E85 prefer the same SOI of 240°bTDC at second and third startup cycle for the flat top piston and high injection pressures. E85 fuel optimal cam timing for startup showed that it tolerates more residuals compared to E10 fuel. Higher internal residuals drives down the Ø requirement for both fuels up to their combustion stability limit, this is thought to be direct benefit to vaporization due to increased cycle start temperature. Benefits are shown for an advance IMOP and retarded EMOP strategy at engine startup. Overall the amount of residuals preferred by an engine for E10 fuel at startup is thought to be constant across engine speed, thus could enable easier selection of optimized cam positions across the startup speeds.

Tracking of industrial objects by using CAD models

In this paper we present a model-based approach for real-time camera pose estimation in industrial scenarios. The line model which is used for tracking is generated by rendering a polygonal model and extracting contours out of the rendered scene. By un-projecting a point on the contour with the depth value stored in the z-buffer, the 3D coordinates of the contour can be calculated. For establishing 2D/3D correspondences the 3D control points on the contour are projected into the image and a perpendicular search for gradient maxima for every point on the contour is performed. Multiple hypotheses of 2D image points corresponding to a 3D control point make the pose estimation robust against ambiguous edges in the image.

Rapid Surface Creation – Schnell zu anspruchsvollen CAD-Flächen mit Tebis

In der CAD-Welt existieren unterschiedliche Arten, wie Oberflächen beschrieben werden. Netze, auch Meshes genannt oder Polymaschen, sind aus einer Vielzahl ebener Dreiecke zusammengesetzt (bis zu mehreren Millionen). Sie stammen aus Digitalisiersystemen oder aus virtueller Modelliersoftware und werden üblicherweise im STL-Format ausgetauscht. Verwandt hierzu sind Netze, die aus Simulationssystemen kommen, beispielsweise zur Umformsimulation von Blechteilen.

Experience and attitudes towards CAM--a survey of internal and psychosomatic patients in a German university hospital

Complementary and alternative medicine (CAM) is popular in Germany. In a consecutive survey the experiences with CAM and the need for a CAM consultation among inpatients of the departments of cardiology (CL), gastroenterology (GE), oncology (OL) and psychosomatics (PS) of the University Hospital Freiburg (FUH) were questionned. Exclusion criteria were inability to understand the questions or a Karnofsky Index < 30%. Four hundred thirty-five patients were included. Three hundred and fifty patients, 100 each in the departments of CL, GE and OL, and 50 in PS answered the questionnaires. Eighty-five patients (20%) refused. Among the 350 patients 26% had previously visited a CAM physician and 19% had visited a CAM therapist (Heilpraktiker). Information about CAM was obtained mainly by television, radio and family members. Frequently used therapies for the current disease were physical training (21%), diet (19%), massage (19%), vitamins/trace elements (19%), herbs (13%), acupuncture (10%) and homeopathy (7%). The highest frequency of CAM use had PS patients, followed by GE, OL and CL patients. High effectivity (> or = 70%) for the current disease, rated on a scale of 4 degrees, had for CL patients physical exercise and massage, for GE patients herbal treatment and for OL patients diet. Physical exercise, diet, massage and herbal treatment generally had better ratings than homeopathy, acupuncture and vitamins. 65% would welcome a CAM center and 53% asked for a consultation about CAM at FUH. OL and GE patients had the strongest (58%), PS patients a lower (52%) and patients with cardiovascular diseases the lowest (43%) interest in a CAM consultation. Twenty-five percent believed, that CAM can help to cope better with their disease. Predictors for a positive attitude towards CAM were young age, aversion to chemical medications (Spearman correlation r = 0.22), desire to participate in therapeutic decisions (r = 0.29), motivation to change, if recommended, the life style (r = 0.31) and desire for a holistic treatment (r = 0.37).

Vorbereitung von CAD-Konstruktionsdaten für den RP-Einsatz – eine Schnittstellenproblematik

Während zunehmend Verfahrensverbesserungen der RP-Technologie Gegenstand aktueller Entwicklungen sind, ist die datentechnische Integration des RP-Prozesses in die CAx-Landschaft nach wie vor nicht ganz problemlos. Seit fast 20 Jahren stellt das STL-Format eine de facto Standardschnittstelle zu RP-Anwendungen dar.

Ermittlung optimaler Bauteilorientierung zur Verbesserung der Prozessplanung in der CAD/RP-Kette

Ein wesentlicher Einflussfaktor auf die Bauteilqualität und Prozessgüte bei der generativen Herstellung von Prototypen ist die Orientierung der Bauteile. So kann eine optimierte Ausrichtung den Treppenstufeneffekt (Staircasing) sowie den Curling-Effekt minimieren und somit die Oberflächenqualität bzw. die Bauteilgenauigkeit erhöhen oder die Berücksichtigung von Formtoleranzen (z.B. Rundheit) ermöglichen. Des Weiteren können verschiedene Bauteilausrichtungen unterschiedliche Ausführungen von Stützkonstruktionen bewirken und die Bauteilstabilität beeinflussen. Diese und ähnliche Wechselwirkungen gilt es bei der Auswahl einer geeigneten Bauteilorientierung für RP-Anwendungen zu berücksichtigen. Dieser Vortrag stellt ein generisches System vor, welches unter Berücksichtigung der genannten Einflussfaktoren sowie weiterer Effekte eine rechnergestützte Optimierung der Bauteilorientierung durchführt. Neben der weiterhin notwendigen Erfahrung der Anwender zur endgültigen Festlegung der fallabhängigen Bauteilausrichtung liefert das System Vorschläge auf Basis einer intensiven Geometrieanalyse, die eine entsprechende Datenaufbereitung im Rahmen der Prozessplanung unterstützen.

Prevalence of cam and pincer-type deformities on hip MRI in an asymptomatic young Swiss female population: a cross-sectional study

OBJECTIVES Femoroacetabular impingement is proposed to cause early osteoarthritis (OA) in the non-dysplastic hip. We previously reported on the prevalence of femoral deformities in a young asymptomatic male population. The aim of this study was to determine the prevalence of both femoral and acetabular types of impingement in young females. METHODS We conducted a population-based cross-sectional study of asymptomatic young females. All participants completed a set of questionnaires and underwent clinical examination of the hip. A random sample was subsequently invited to obtain magnetic resonance images (MRI) of the hip. All MRIs were read for cam-type deformities, increased acetabular depths, labral lesions, and impingement pits. Prevalence estimates of cam-type deformities and increased acetabular depths were estimated, and relationships between deformities and signs of joint damage were examined using logistic regression models. RESULTS The study included 283 subjects, and 80 asymptomatic females with a mean age of 19.3 years attended MRI. Fifteen showed some evidence of cam-type deformities, but none were scored to be definite. The overall prevalence was therefore 0% [95% confidence interval (95% CI) 0-5%]. The prevalence of increased acetabular depth was 10% (95% CI 5-19). No association was found between increased acetabular depth and decreased internal rotation of the hip. Increased acetabular depth was not associated with signs of labral damage. CONCLUSIONS Definite cam-type deformities in women are rare compared to men, whereas the prevalence of increased acetabular depth is higher, suggesting that femoroacetabular impingement has different gender-related biomechanical mechanisms.

Arthroscopic versus open cam resection in the treatment of femoroacetabular impingement

PURPOSE The purpose of this study was to evaluate if osseous correction of the femoral neck achieved arthroscopically is comparable to that achieved by surgical dislocation. METHODS We retrospectively analyzed all patients who were treated with hip arthroscopy or surgical dislocation for cam or mixed type femoroacetabular impingement (FAI) in our institution between 2006 and 2009. Inclusion criteria were complete clinical and radiologic documentation with standardized radiographs. Group 1 consisted of 66 patients (49 female patients, mean age 33.8 years) treated with hip arthroscopy. Group 2 consisted of 135 patients (91 male patients, mean age 31.2 years) treated with surgical hip dislocation. We compared the preoperative and postoperative alpha and gamma angles, as well as the triangular index. Mean follow-up was 16.7 months (range, 2 to 79 months). RESULTS In group 1, the mean alpha angle improved from 60.7° preoperatively to 47.8° postoperatively (P < .001) and the mean gamma angle improved from 47.3° to 44.5° (P < .001). Over time, the preoperative mean alpha angle increased from 56.3° in 2006 to 67.5° in 2009, whereas the postoperative mean alpha angle decreased from 51.2° in 2006 to 47.5° in 2009. In group 2, the mean alpha angle improved from 75.3° preoperatively to 44.8° postoperatively (P < .001), and the mean gamma angle improved from 65.1° to 52.2° (P < .001). Arthroscopic revision of intra-articular adhesions was performed in 4 patients (6.1%) in group 1 and 16 patients (12%) in group 2. Three patients (2.2%) in group 2 underwent revision for nonunion of the greater trochanter. CONCLUSIONS Osseous correction of cam-type FAI with hip arthroscopy is comparable to the correction achieved by surgical hip dislocation. There is a significant learning curve for hip arthroscopy, with postoperative osseous correction showing improved results with increasing surgical experience. LEVEL OF EVIDENCE Level III, retrospective comparative study.

Experimentally induced cam impingement in the sheep hip

Sheep hips have a natural non-spherical femoral head similar to a cam-type deformity in human beings. By performing an intertrochanteric varus osteotomy, cam-type femoro-acetabular impingement (FAI) during flexion can be created. We tested the hypotheses that macroscopic lesions of the articular cartilage and an increased Mankin score (MS) can be reproduced by an experimentally induced cam-type FAI in this ovine in vivo model. Furthermore, we hypothesized that the MS increases with longer ambulatory periods. Sixteen sheep underwent unilateral intertrochanteric varus osteotomy of the hip with the non-operated hip as a control. Four sheep were sacrificed after 14, 22, 30, and 38-weeks postoperatively. We evaluated macroscopic chondrolabral alterations, and recorded the MS, based on histochemical staining, for each ambulatory period. A significantly higher prevalence of macroscopic chondrolabral lesions was found in the impingement zone of the operated hips. The MS was significantly higher in the acetabular/femoral cartilage of the operated hips. Furthermore, these scores increased as the length of the ambulatory period increased. Cam-type FAI can be induced in an ovine in vivo model. Localized chondrolabral degeneration of the hip, similar to that seen in humans (Tannast et al., Clin Orthop Relat Res 2008; 466: 273-280; Beck et al., J Bone Joint Surg Br 2005; 87: 1012-1018), can be reproduced. This experimental sheep model can be used to study cam-type FAI.

The cam-type deformity - what is it: SCFE, osteophyte, or a new disease?

Cam-type deformity of the proximal femur is a risk factor for the development of cam-type femoroacetabular impingement and a prearthrotic condition of the hip. The etiology of cam-type deformity remains unclear. There are a number of causes of cam-type deformity including sequellae of slipped capital femoral epiphysis, Legg-Calvé-Perthes disease or Perthes-like deformities, postinfectious, and traumatic. However, the majority of cam-type deformities arise without any apparent preexisting hip disease. These "idiopathic" cam-type deformities likely represent a majority of cases, and show clear racial and sex differences, as well as developmental and genetic influences. Idiopathic cam-type deformity also seems to be a distinct entity from residual or silent slipped capital femoral epiphysis, as well as osteoarthritis-induced osteophytes. In this paper we examine the different pathogenetic aspects of the proximal femur that contribute to cam-type deformity and/or symptomatic cam-type femoroacetabular impingement.

Growth plate alteration precedes cam-type deformity in elite basketball players

BACKGROUND Vigorous sporting activity during the growth years is associated with an increased risk of having a cam-type deformity develop. The underlying cause of this osseous deformity is unclear. One may speculate whether this is caused by reactive bone apposition in the region of the anterosuperior head-neck junction or whether sports activity alters the shape of and growth in the growth plate. If the latter is true, then one would expect athletes to show an abnormal shape of the capital growth plate (specifically, the epiphyseal extension) before and/or after physeal closure. QUESTIONS/PURPOSES We therefore raised three questions: (1) Do adolescent basketball players show abnormal epiphyseal extension? (2) Does the epiphyseal extension differ before and after physeal closure? (3) Is abnormal epiphyseal extension associated with high alpha angles? METHODS We performed a case-control comparative analysis of young (age range, 9-22 years) male elite basketball athletes with age-matched nonathletes, substratified by whether they had open or closed physes. We measured epiphyseal extension on radial-sequence MRI cuts throughout the cranial hemisphere from 9 o'clock (posterior) to 3 o'clock (anterior). Epiphyseal extension was correlated to alpha angle measurements at the same points. RESULTS Epiphyseal extension was increased in all positions in the athletes compared with the control group. On average, athletes showed epiphyseal extension of 0.67 to 0.83 versus 0.53 to 0.71 in control subjects. In the control group epiphyseal extension was increased at all measurement points in hips after physeal closure compared with before physeal closure. In contrast, the subgroup of athletes with a closed growth plate only had increased epiphyseal extension at the 3 o'clock position compared with the athletes with an open [corrected] growth plate (0.64-0.70). We observed a correlation between an alpha angle greater than 55° and greater epiphyseal extension in the anterosuperior femoral head quadrant: the corresponding Spearman r values were 0.387 (all hips) and 0.285 (alpha angle>55°) for the aggregate anterosuperior quadrant. CONCLUSIONS These findings suggest that a cam-type abnormality in athletes is a consequence of an alteration of the growth plate rather than reactive bone formation. High-level sports activity during growth may be a new and distinct risk factor for a cam-type deformity.

Evaluating the prevalence, content and readability of complementary and alternative medicine (CAM) web pages on the internet.

Complementary and alternative medicine (CAM) use is growing rapidly. As CAM is relatively unregulated, it is important to evaluate the type and availability of CAM information. The goal of this study is to deter-mine the prevalence, content and readability of online CAM information based on searches for arthritis, diabetes and fibromyalgia using four common search engines. Fifty-eight of 599 web pages retrieved by a "condition search" (9.6%) were CAM-oriented. Of 216 CAM pages found by the "condition" and "condition + herbs" searches, 78% were authored by commercial organizations, whose pur-pose involved commerce 69% of the time and 52.3% had no references. Although 98% of the CAM information was intended for consumers, the mean read-ability was at grade level 11. We conclude that consumers searching the web for health information are likely to encounter consumer-oriented CAM advertising, which is difficult to read and is not supported by the conventional literature.