Analysis of the Differences between Force Control and Feed Control Strategies during the Honing of Bores

AbstractHoning is a machining process that can economically produce very exact bores regarding form, geometry and surface quality. It is mainly used as the final finishing operation for ready made parts and typically conducted on the inner surface of a cylinder. Due to their specific surface structure which has a good ability to keep lubricants and a high wear resistance, honed parts usually serve as functional surfaces to guide moved parts. Today, the main fields for applications of honing technology can be found in most sectors of the metal working industry, e.g. the automotive industries, hydraulic and pneumatic manufacture and aircraft industries. During the long-stroke honing process the tool, equipped with one or several abrasive honing stones, is performing three overlaying movement components. These are a rotational movement, an oscillating stroke movement in axial direction and the radial feed movement of the honing stone. This feed movement is one of the decisive factors for the results of the honing process. It can be realized through feed control or, in a more recent approach, through force control strategies. By feed controlled honing, the position of the honing stone is changed in defined invariable steps in certain time intervals. In contrast, by force controlled honing the force of the honing stone against the wall of the workpiece is measured indirectly by a force sensor, which is located within the feed unit of the honing machine. A required force value is given and, if necessary, the honing stone is fed outwards to reach and maintain a constant cutting force throughout the honing process. This constant force is supposed to produce better results of the honing process in terms of geometric and form accuracy as well as surface structure. The presented research studies aim at improving process know-how to further increase the production accuracy and process repeatability. In a comparison between parts honed with the two different feeding strategies for the honing stone, force components and moments were analyzed and correlated to the phases of the process and several influencing parameters. In addition to the forces and moments measured during the honing process, the quality parameters of the honed parts have also been analyzed and compared

Darbo motyvacija ir savarankiškumas karjeroje kaip moterų subjektyvios sėkmės STEM karjeroje prediktoriai

The minority status of women in science, technology, engineering and mathematics (STEM) professions makes their successful career development difficult. Due to gender-specific challenges, career dissatisfaction contributes to women dropping out of STEM careers. Therefore, women’s subjective career success (SCS) is important to persist and progress in their STEM careers. This study analyzed the influence of different types of work motivation and the perceived career autonomy on SCS of women. Specifically, 318 women working in STEM professions in Germany completed a quantitative online questionnaire. Using an ordinary least squares regression for variables predicting SCS measured as career satisfaction, we found that an intrinsic work motivation positively affects women’s SCS. The perception of high career autonomy was related positively, and the perception of low career autonomy was related negatively to SCS. Unexpectedly, the findings also revealed the positive influence of income on women’s SCS. The findings show that intrinsic work motivation and high perceived autonomy are promoting factors for SCSs, which could also contribute to their retention in STEM professions.Mokslo, technologijų, inžinerijos ir matematikos (STEM) profesijose moterų yra mažuma, todėl moterims čia sunku siekti sėkmingos karjeros. Moterų nepasitenkinimas savo profesija kyla dėl su socialine lytimi susijusių problemų ir prisideda prie to, kad moterys nutraukia STEM veiklas. Todėl norinčioms išlikti ir tobulėti STEM profesijose moterims svarbi subjektyvi karjeros sėkmė (SKS). Šiame tyrime analizuojama įvairių darbo motyvacijos tipų ir savarankiškumo karjeroje įtaka moterų subjektyviai karjeros sėkmei. 318 STEM profesijose Vokiet­ijoje dirbančių moterų užpildė kiekybinį klausimyną internete. Naudodami įprastą mažiausiųjų kvadratų regresiją subjektyvią karjeros sėkmę (matuojamą pasitenkinimu karjera) prognozuojantiems kintamiesiems nustatėme, kad teigiamai moterų SKS prognozuoja vidinė darbo motyvacija. Didelis savarankiškumas karjeroje su SKS susijęs teigiamai, o mažas savarankiškumas karjeroje – neigiamai. Tyrimo rezultatai netikėtai atskleidė ir teigiamą pajamų įtaką moterų SKS. Rezultatai rodo, kad vidinė darbo motyvacija ir didelis savarankiškumas yra tie skatinantys SKS veiksniai, kurie taip pat galėtų prisidėti prie moterų išlaikymo STEM profesijose

eMZed: an open source framework in Python for rapid and interactive development of LC/MS data analysis workflows

Summary: The Python-based, open-source eMZed framework was developed for mass spectrometry (MS) users to create tailored workflows for liquid chromatography (LC)/MS data analysis. The goal was to establish a unique framework with comprehensive basic functionalities that are easy to apply and allow for the extension and modification of the framework in a straightforward manner. eMZed supports the iterative development and prototyping of individual evaluation strategies by providing a computing environment and tools for inspecting and modifying underlying LC/MS data. The framework specifically addresses non-expert programmers, as it requires only basic knowledge of Python and relies largely on existing successful open-source software, e.g. OpenMS. Availability: The framework eMZed and its documentation are freely available at http://emzed.biol.ethz.ch/. eMZed is published under the GPL 3.0 license, and an online discussion group is available at https://groups.google.com/group/emzed-users. Contact: [email protected] Supplementary information: Supplementary data are available at Bioinformatics onlin

Early Tube Feeding after Percutaneous Endoscopic Gastrostomy (PEG): An Observational Study.

This study investigated whether enteral nutrition by early tube feeding led to changes in clinical parameters compared to tube feeding after 24 h. Starting on 1 January 2021, and following the latest update of the ESPEN guidelines on enteral nutrition, patients with percutaneous endoscopic gastrostomy (PEG) received tube feeding 4 h after tube insertion. An observational study was conducted to analyze whether the new scheme affected patient complaints, complications, or hospitalization duration compared to the previous procedure of tube feeding starting after 24 h. Clinical patient records from one year before and one year after the introduction of the new scheme were examined. A total of 98 patients were included, and of those 47 received tube feeding 24 h after tube insertion, and 51 received tube feeding 4 h after tube insertion. The new scheme did not influence the frequency or severity of patient complaints or complications related to tube feeding (all p-values > 0.05). However, the study showed that the length of stay in hospital was significantly shorter when following the new scheme (p = 0.030). In this observational cohort study an earlier start of tube feeding did not produce any negative consequences but did reduce the duration of hospitalization. Therefore, an early start, as suggested in the recent ESPEN guidelines, is supported and recommended

Distribution of structure and lignin within growth rings of Norway spruce

A radial core from a Norway spruce (Picea abies (L.) Karst.) estimated to be about 107years old was cut from a board and was analyzed for density and microfibril angle (MFA). Furthermore, cell geometry, wall thickness and lignin distribution were analyzed on three selected growth rings in detail. Intra-ring differences in the density profiles are also true for cell wall thicknesses as well as radial and tangential lumen diameters. A higher MFA was found for earlywood with a slow decrease toward the latewood region. The lignin was found to remain rather constant throughout the growth rings, which suggests a constant chemical composition of the cell wall material within the growth ring. From the recorded datasets on a cellular level, it can be concluded that the main adaptation regarding structure-property relationships toward the optimization of water transport and mechanical stability is mainly achieved at the cell leve

Poly–adenosine diphosphate–ribose polymerase inhibition for myocardial protection: Pathophysiologic and physiologic considerations

Plantilles de l’Institut Barcelona Esports, de l’Institut Municipal del Paisatge Urbà i la Qualitat de Vida, de l’Institut Municipal d'Informàtica, de l’Institut Municipal d'Hisenda, de l’Institut Municipal d'Educació, de l’Institut Municipal de Mercats, de l’Institut Municipal de Serveis Socials i de l’Institut Municipal de Persones amb Discapacita

Microscopic studies on modified wall structure and lignin topochemistry in xylem fibres of poplar after wounding

Information about fine structure following wounding in differentiating xylem tissue is still scarce. This study provides information on cell wall modifications with special emphasis on lignin distribution in xylem fibres of poplar differentiating at the time of wounding. Samples were collected from wounded Populus spp. trees after response periods of up to twenty-three months and processed for microscopic analyses. General studies on the wall structure of wound-adjacent xylem fibres were carried out with light and transmission electron microscopy, whereas lignin distribution patterns of these cells were examined by UV-microspectrophotometry.Xylem fibres close to the wound and within a transition zone between differentiated xylem laid down prior to and tissue laid down after wounding developed a distinctively thicker secondary wall than normal fibres. These modified walls also showed a slightly higher lignin content, than normal and a heterogeneous lignin distribution in the middle lamella and the secondary wall.Wounding in poplar induces a modified wall structure and lignin topochemistry in xylem fibres differentiating at the time of wounding. It is assumed that this wound response is part of the compartmentalization process and therefore contributes to an increased resistance.

Comparing eye movements recorded by search coil and infrared eye tracking

Objective: The performance of a new video-based infrared eye tracker (IR) was compared to the magnetic search coil technique (SC). Since the IR offers interesting possibilities as a diagnostic tool in neuro-ophthalmology, it was investigated whether the new device has overcome shortcomings that were reported from former IR systems. Methods: Horizontal saccades were recorded using the IR and the SC. The IR allowed eye movement recordings at different sampling rates ranging from 250Hz to 1000Hz while the SC recorded at 1000Hz. Results/Conclusions: The results show that the IR and the SC were in good agreement and produced similar results. In contrast to other studies, the influence of the sampling rate of the IR was small. The saccade main-sequences did not show significant differences. The latency times observed for both systems were mainly in the short-latency rang

Biogeography of Italy revisited : genetic lineages confirm major phylogeographic patterns and a pre-Pleistocene origin of its biota

Warm-adapted species survived the cold stages of the past glacial-interglacial cycles in southern European peninsulas and recolonized major parts of Central and Northern Europe in the wake of postglacial warming. However, many of the genetic lineages which differentiated within these refugia predate even the Pleistocene. One of these refugia is the Italian Peninsula with its surrounding islands. In this meta-analysis, we compiled phylogeographic patterns of multiple species across this region. We transformed existing geographic information on 78 animal and plant species (with a total of 471 genetic lineages) within 17 predefined areas into presence/absence matrices. We elaborated three matrices: (i) only old lineages exclusively distinguished by deep splits, (ii) only young lineages distinguished by shallow (i.e. recent) splits, and (iii) presence/absence of the respective species. To infer biogeographic relationships between the predefined areas, we performed bootstrapped neighbour joining cluster analyses on these three matrices. In addition, we reviewed the geological history of Italy to identify causes of the observed biogeographic patterns. We found Sardinia and Corsica to be biogeographically closely linked with each other, and that they diverge strongly from all other regions. Sicily also diverges strongly from all other regions, while the intra-island differentiation was comparatively low. On the Italian mainland, Calabria exhibited the most pronounced biogeographic differentiation, often with several lineages present, resulting from old vicariance events within the region. Furthermore, southern Apulia and the Po Plain with adjoining areas of northern peninsular Italy displayed considerable distinctiveness. Admixture prevailed in the areas between these three regions. The ancient isolation of Sicily, as well as Sardinia plus Corsica, resulted in endemic lineages with only moderate recent exchange with adjacent mainland regions. Pronounced diversification occurs within the Italian Peninsula. The complex tectonic activities, such as shifting (micro)plates, submergence of major parts of peninsular Italy with the genesis of numerous Pliocene islands, in combination with the climatic cycles during the Pleistocene have most likely generated the current biogeographic pattern of species. Immigrations from the Balkan Peninsula into northern Italy partly accounted for the distinctiveness of this region