Drop forging of gear wheel

Práce předkládá návrh technologie výroby ozubeného kola z kruhového přířezu jakosti 12 050. Na základě literární studie zápustkového kování a výpočtů byl navržen technologický postup výroby. Návrh zápustek bude proveden na základě příslušných norem, materiál zápustek bude ocel 19 552. Vzhledem k tvarové složitosti a rozměrům ozubeného kola budou použity tři operace. Na základě vypočtené kovací síly byl zvolen svislý kovací list LMZ 1600 A/S se jmenovitou sílou 16 MN. Vzhledem k použití lisu bude zápustka opatřena vyhazovačem.The project elaborated design of technology production of gear wheel from circular blanks of steel 12 050. Pursuant to of the literary pursuit a problem of the die forging and calculation was designed manufacturing process. Dies proposal will be based on relevant standards, materials die steel will be 19 552. Given the complexity of the shape and dimensions of the gear will be used in three operations. Based on the calculated forging force was chosen vertical forging sheet LMZ 1600 A/S with a nominal power of 16 MN. Due to the use of the press die is provided with an ejector.

Evidence-based commentary on the diagnosis, management, and further research of degenerative cervical spinal cord compression in the absence of clinical symptoms of myelopathy

ABSTRACT: Degenerative cervical myelopathy (DCM) represents the final consequence of a series of degenerative changes in the cervical spine, resulting in cervical spinal canal stenosis and mechanical stress on the cervical spinal cord. This process leads to subsequent pathophysiological processes in the spinal cord tissues. The primary mechanism of injury is degenerative compression of the cervical spinal cord, detectable by magnetic resonance imaging (MRI), serving as a hallmark for diagnosing DCM. However, the relative resilience of the cervical spinal cord to mechanical compression leads to clinical-radiological discordance, i.e., some individuals may exhibit MRI findings of DCC without the clinical signs and symptoms of myelopathy. This degenerative compression of the cervical spinal cord without clinical signs of myelopathy, potentially serving as a precursor to the development of DCM, remains a somewhat controversial topic. In this review article, we elaborate on and provide commentary on the terminology, epidemiology, natural course, diagnosis, predictive value, risks, and practical management of this condition—all of which are subjects of ongoing debate

HARDI-ZOOMit protocol improves specificity to microstructural changes in presymptomatic myelopathy

ABSTRACT: Diffusion magnetic resonance imaging (dMRI) proved promising in patients with non-myelopathic degenerative cervical cord compression (NMDCCC), i.e., without clinically manifested myelopathy. Aim of the study is to present a fast multi-shell HARDI-ZOOMit dMRI protocol and validate its usability to detect microstructural myelopathy in NMDCCC patients. In 7 young healthy volunteers, 13 age-comparable healthy controls, 18 patients with mild NMDCCC and 15 patients with severe NMDCCC, the protocol provided higher signal-to-noise ratio, enhanced visualization of white/gray matter structures in microstructural maps, improved dMRI metric reproducibility, preserved sensitivity (SE = 87.88%) and increased specificity (SP = 92.31%) of control-patient group differences when compared to DTI-RESOLVE protocol (SE = 87.88%, SP = 76.92%). Of the 56 tested microstructural parameters, HARDI-ZOOMit yielded significant patient-control differences in 19 parameters, whereas in DTI-RESOLVE data, differences were observed in 10 parameters, with mostly lower robustness. Novel marker the white-gray matter diffusivity gradient demonstrated the highest separation. HARDI-ZOOMit protocol detected larger number of crossing fibers (5–15% of voxels) with physiologically plausible orientations than DTI-RESOLVE protocol (0–8% of voxels). Crossings were detected in areas of dorsal horns and anterior white commissure. HARDI-ZOOMit protocol proved to be a sensitive and practical tool for clinical quantitative spinal cord imaging

Diffusion magnetic resonance imaging reveals tract‐specific microstructural correlates of electrophysiological impairments in non‐myelopathic and myelopathic spinal cord compression

ABSTRACT: Background and purpose: Non- myelopathic degenerative cervical spinal cord compres-sion (NMDC) frequently occurs throughout aging and may progress to potentially irre-versible degenerative cervical myelopathy (DCM). Whereas standard clinical magnetic resonance imaging (MRI) and electrophysiological measures assess compression sever-ity and neurological dysfunction, respectively, underlying microstructural deficits still have to be established in NMDC and DCM patients. The study aims to establish tract- specific diffusion MRI markers of electrophysiological deficits to predict the progression of asymptomatic NMDC to symptomatic DCM. Methods: High-resolution 3 T diffusion MRI was acquired for 103 NMDC and 21 DCM patients compared to 60 healthy controls to reveal diffusion alterations and relation-ships between tract-specific diffusion metrics and corresponding electrophysiological measures and compression severity. Relationship between the degree of DCM disability, assessed by the modified Japanese Orthopaedic Association scale, and tract-specific mi-crostructural changes in DCM patients was also explored. Results: The study identified diffusion-derived abnormalities in the gray matter, dor-sal and lateral tracts congruent with trans-synaptic degeneration and demyelination in chronic degenerative spinal cord compression with more profound alterations in DCM than NMDC. Diffusion metrics were affected in the C3-6 area as well as above the com-pression level at C3 with more profound rostral deficits in DCM than NMDC. Alterations in lateral motor and dorsal sensory tracts correlated with motor and sensory evoked po-tentials, respectively, whereas electromyography outcomes corresponded with gray mat-ter microstructure. DCM disability corresponded with microstructure alteration in lateral columns. Conclusions: Outcomes imply the necessity of high- resolution tract-specific diffusion MRI for monitoring degenerative spinal pathology in longitudinal studies

Czech Press, 1945-48

This paper is dedicated the study of the Cyech press between 1945-48. The autor deals with the new organization of the Czech press after the WW II. Political parties perceived the press as being national property, the subject of public interest. The privately-owned press was forbudden in 1945. Onlz political parties or special-interest organisation could publish daily newpapers and magazines. Rhe author describes the activities of Václav Kopecký - a communist who directed the Ministry of Information. The author characterizes the influence of this ministry on the organization of the Czech press

Television Serial "Synové a dcery Jakuba skláře" and its Reflection of more than 50 years of our History.

Author describes the circumstances of the shooting. He analyses the story and the characters in the serial. Using the newspapers reviews he illustrates the way of evaluation by the contemporary reviewers

The role of broadcasting media in the period 1968-1969

In the text, the authors study the activities of Czechoslovakian radio and television in the years 1968-1969. They describe how the media supported the politics of the Czechoslovakian Communist Party led by Alexander Dubček during the Prague spring. The authors analyse what form normalization took in both media

Content changes of Czech television series in 1989-2009

The text analyses content changes (types of main characters, change of the narativity) of Czech television series in 1989-2009