Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “assembly operations”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMedDate not supplied

Design of a work system considering the needs of aged workers.

The aim of this paper is to explore and present a proposal for a new work system for the aged worker. The method of research used to establish the system was to observe, record, and measure the actions of sitting workers performing assembly operations on electrical products. An evaluation index used in this study was obtained by measuring the motion time, cycle time per product, and the workload (CFF: Critical Flicker Fusion Frequency and Subjective Symptom of Fatigue). The results lead to the new work system being identified and to the reduction of handling motion of get and place work and the work load. It was determined that the system is adaptable for aged workers.

Aging↗
PubMed2003

Hand lacerations and job design characteristics in line-paced assembly.

This study investigated risk factors for laceration injuries among workers employed in line-paced manufacturing assembly operations. Most lacerations (76% of 576) occurred on the hands and fingers (grouped as "hand" lacerations). On average, 37% of surveyed workers reported at least one laceration to the hand in the preceding year, resulting in an overall hand laceration rate of 83 per 100 workers per year. An inverse relationship was found between level of job routinization and hand lacerations, with progressively higher rates of hand lacerations occurring among workers assigned to less routine (more variable) work patterns. Fabricated metal parts handling and job variability may be related to increased risk of hand lacerations in line-paced work environments where personal protective equipment is the primary strategy to control exposure to sharp objects.

Accidents, Occupational↗
PubMedDate not supplied

Using visual cues of contact to improve interactive manipulation of virtual objects in industrial assembly/maintenance simulations.

This paper describes a set of visual cues of contact designed to improve the interactive manipulation of virtual objects in industrial assembly/maintenance simulations. These visual cues display information of proximity, contact and effort between virtual objects when the user manipulates a part inside a digital mock-up. The set of visual cues encloses the apparition of glyphs (arrow, disk, or sphere) when the manipulated object is close or in contact with another part of the virtual environment. Light sources can also be added at the level of contact points. A filtering technique is proposed to decrease the number of glyphs displayed at the same time. Various effects--such as change in color, change in size, and deformation of shape- can be applied to the glyphs as a function of proximity with other objects or amplitude of the contact forces. A preliminary evaluation was conducted to gather the subjective preference of a group of participants during the simulation of an automotive assembly operation. The collected questionnaires showed that participants globally appreciated our visual cues of contact. The changes in color appeared to be preferred concerning the display of distances and proximity information. Size changes and deformation effects appeared to be preferred in terms of perception of contact forces between the parts. Last, light sources were selected to focus the attention of the user on the contact areas.

Journal Article↗
PubMed1998

Trends in rates of occupational fatal injuries in the United States (1983-92).

OBJECTIVES: An updated version of a national surveillance system of traumatic occupational fatalities was used to explore adjusted and unadjusted trends in rates of fatal injury. METHODS: Data from the national traumatic occupational fatalities surveillance system were combined with data on employment from the United States Bureau of Labor Statistics. Poisson regression was then used to examine trends in rates of occupational fatality injuries while controlling for demographic and workplace characteristics. RESULTS: Adjusted annual changes in rates of fatal injuries ranged from a decline of 6.2% for workers in technical and administrative support occupations--for example, health, science, and engineering technicians, pilots, computer programmers--to an increase of 1.6% in machine operators, assemblers, and inspectors. For industries, annual changes ranged from a decline of 5.3% for workers in public administration--for example, justice, public order, and safety workers--to an increase of 2.6% for workers in the wholesale trade. By comparison, the annual decline over all industries and occupations was 3.1%. In many industries and occupations, an effect modification of annual trends by the age of the worker was also found with the oldest workers experiencing either no decline or a significant increase in rates of fatal injuries. CONCLUSIONS: This general pattern of decline, adjusted for the effects of demographic characteristics of the worker population, is encouraging; however, increases in rates of fatal injuries found in particular industries and occupations, suggest appropriate targets for increased injury prevention efforts.

Accidents, Occupational↗
PubMed2005

[Occupational differences in exposure to hazardous work conditions].

BACKGROUND: Few studies have been aimed at describing organizational and psychosocial conditions of the Italian workforce by occupational group, and they have been mainly conducted within specific occupations. OBJECTIVES: The present study aimed at identifying specific groups of occupations which have unfavourable profiles from the point of view of exposure to specific organizational factors and psychosocial risks, and to physical, chemical and ergonomic risks, and analyzing their distribution by worker age. METHODS: The analysis was conducted on a sample of 4,195 workers in the Piedmont Region who were members of the CGIL Trade Union (Italian General Confederation of Labour), who answered a self-administered questionnaire in 2000, aimed at assessing chemical, physical, and ergonomic risks, accidents, and psychosocial factors connected with work organization and work tasks. Psychosocial risks were assessed via three scales aimed at measuring the degree of control, psychophysical demands, and worker satisfaction. The proportion of workers exposed to the above mentioned risks was analysed according to occupational group. This group was then compared with all other groups taken together, according to prevalence of high strain condition (combination of high demand and low control) and HSUR condition (High Strain Unfairly Rewarded; combination of high strain and low satisfaction). RESULTS: Among males aged 25-44 years, restricted to the occupation groups with more than ten workers in high strain condition, significantly higher proportions of stress were observed in leather workers and shoemakers, paper factory workers, rubber workers, crane and bridge crane operators, plastic workers, painters, transport drivers and carpenters. For many of these groups, excesses were confirmed for the HSUR condition. Among subjects aged over 44 years, a higher risk for high strain was confirmed in rubber workers, transport drivers and carpenters. In addition, machine tool operators, assembly line and mechanical workers in this age group were exposed to higher risk of stress. In younger women there was a significantly higher risk of both high strain and HSUR conditions in workers employed in the rubber, plastic and the food industries, and in machine tool workers. Such excess risk was confirmed in the latter three categories also among older women. In general, the proportion of male workers classified as working in high strain conditions decreased as age increased, while in women it remained stable. CONCLUSIONS: The study allowed evaluation of the differential impact of exposure to physical, chemical, and psychosocial risk factors among occupational groups, thus contributing to the identification and classification of exhausting jobs. The results further showed, particularly among men, a smaller proportion of older workers, compared to younger ones, exposed to harmful physical, chemical, ergonomic and psychosocial conditions, indicating a possible propensity of companies to adapt workplace conditions, organization and internal mobility to worker age.

Accidents, Occupational↗
PubMed1990

Occupational asthma due to alkyl cyanoacrylate.

A case of bronchial asthma induced by occupational exposure to alkyl cyanoacrylate, an adhesive, occurred in an assembly operation. Provocative exposure testing induced immediate and delayed asthmatic responses. Alkyl cyanoacrylate seemed to act as an allergen or as an irritant, resulting in the development of asthma.

Adhesives↗
PubMed1984

Allergic contact dermatitis from anaerobic acrylic sealants.

Three patients employed in electronic assembly operations had allergic contact dermatitis to polyethylene glycol (PEG) dimethacrylate, found in an anaerobic sealant. Clinical features in all three cases consisted of eczema localized predominantly on the distal parts of the fingers and the palmar aspects of fingertips; onycholysis developed in one patient. No cross reactions to methyl methacrylate were observed on patch testing. Guinea pig maximization testing with both the commercially available sealant and the active resin demonstrated that PEG dimethacrylate is a moderate skin sensitizer.

Acrylic Resins↗
PubMed2000

Assessment of exposure to manganese in welding operations during the assembly of heavy excavation machinery accessories.

Welder exposure to metals in various industrial sectors is poorly characterized. We had the opportunity to carry out an exploratory study to characterize manganese exposure in welding operations in a recently established Quebec factory that assembled accessories for heavy excavation machinery. Ten workers were sampled for total manganese for at least two consecutive days out of three followed by two consecutive days for respirable manganese (with a size selective sampler with a median cut-off of 4 microns), during a typical week in the summer of 1998. Parts being welded were characterized as large or small. Small parts were those being welded on tables during subassembly. Workers were divided into two groups according to the parts they were welding. Seventy-eight percent of the total manganese exposure levels of welding operations during the assembly of large accessories of heavy excavation machinery exceeded the manganese American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value (TLV) of 0.20 mg/m3 (GM 0.24 mg/m3, n = 14) while none exceeded the TLV during the assembly of small pieces (GM 0.06 mg/m3, n = 8). Welding operations during the assembly of large heavy excavation machinery accessories may pose a significant health hazard. Considering the importance of task-related variables affecting exposure among workers, further studies are needed to better characterize exposure determinants of welding operations during the assembly of heavy excavation machinery accessories.

Adult↗
PubMed1996

Cortico-thalamic interplay and the security of operation of neural assemblies and temporal chains in the cerebral cortex.

Much evidence suggests that the mammalian thalamus is not merely a set of nuclei relaying signals to the cerebral cortex, but is engaged in two-way interplay with it. Three important features constrain ideas about the nature of this interplay: (i) thalamic projection neurones lack local axon collaterals; (ii) most corticothalamic projections have very long axonal conduction time; (iii) in the waking state the membrane potential of thalamic projections cells appears to be poised just beneath threshold for firing. It is proposed that corticothalamo-cortical pathways represent connections between different cortical loci which have higher security than the direct cortico-cortical route. Thus each thalamo-cortical projection neurone can have a singular and pivotal role in the activation of one or more cortical neural assemblies. The long delays of cortico-thalamic conduction suggest that the cortico-thalamo-cortical loop also plays a crucial role in the operation of time-structured neural assemblies ('synfire chains'; Abeles), by providing a high-security link from one active node of the chain to nodes activated at a later time in the sequence. It is predicted that, in the waking animal, thalamic projection cells should have a response selectivity to complex percepts and concepts, conferred on them by the cortical assemblies in whose activation they participate.

Afferent Pathways↗
PubMed1994

[Microbiologic study of anterior chamber contents after cataract surgery].

The authors present an account of the results of cultivation of the contents of the anterior chamber at the end of cataract operations. Data assembled during 50 operations are evaluated. The material was cultivated on solid and liquid media. The assembled results indicate that only cultivation from the surgical wound or eye contents at the end of the operation can provide a reliable picture of the microbial population in case of inflammatory complications.

Anterior Chamber↗
PubMedDate not supplied

Bacterial secretome: the assembly manual and operating instructions (Review).

Bacterial protein secretion is a complex multi-stage reaction that is central to membrane and cell wall biosynthesis and essential for cell viability. An impressive array of experimental tools have been used to dissect this reaction into discreet sub-reactions. Synthesis of these data reveals a fascinating cascade of inter- and intra-molecular interactions that select, sort and target secretory polypeptides to the membrane and then spend metabolic energy to bias their vectorial movement across the membrane plane through a lipid-inaccessible proteinaceous environment. Transmembrane crossing is catalyzed by protein translocase, an astonishingly dynamic molecular machine. The unusual molecular features of the Sec pathway components allows a handful of proteins to catalyze the export of hundreds of secretory polypeptide substrates with astonishing fidelity. Knowledge of the molecular details of the secretion pathway allows us to rationally exploit these features in heterologous protein production biotechnologies and in the development of novel antibiotics.

Adenosine Triphosphatases↗
PubMed2003

Caveolin-1 contributes to assembly of store-operated Ca2+ influx channels by regulating plasma membrane localization of TRPC1.

TRPC1, a component of store-operated Ca2+ entry (SOCE) channels, is assembled in a complex with caveolin-1 (Cav1) and key Ca2+ signaling proteins. This study examines the role of Cav1 in the function of TRPC1. TRPC1 and Cav1 were colocalized in the plasma membrane region of human submandibular gland and Madin-Darby canine kidney cells. Full-length Cav1 bound to both the N and C termini of TRPC1. Amino acids 271-349, which includes a Cav1 binding motif (amino acids 322-349), was identified as the Cav1 binding domain in the TRPC1 N terminus. Deletion of amino acids 271-349 or 322-349 prevented plasma membrane localization of TRPC1. Importantly, TRPC1Delta271-349 induced a dominant suppression of SOCE and was associated with wild-type TRPC1. Although the role of the C-terminal Cav1 binding domain is not known, its deletion did not affect localization of TRPC1 (Singh, B. B., Liu, X., and Ambudkar, I. S. (2000) J. Biol. Chem. 275, 36483-36486). Further, expression of a truncated Cav1 (Cav1Delta51-169), but not full-length Cav1, similarly disrupted plasma membrane localization of endogenously and exogenously expressed TRPC1 in human submandibular gland and Madin-Darby canine kidney cells. Cav1Delta51-169 also suppressed thapsigarginand carbachol-stimulated Ca2+ influx and increased the detergent solubility of TRPC1, although plasma membrane lipid raft domains were not disrupted. These data demonstrate that plasma membrane localization of TRPC1 depends on an interaction between its N terminus and Cav1. Thus, our data suggest that Cav1 has an important role in the assembly of SOCE channel(s).

Amino Acid Sequence↗
PubMedDate not supplied

Metabolic assessments during extra-vehicular activity.

Extra-vehicular activity (EVA) has a significant role during extended space flights. It demonstrates that humans can survive and perform useful work outside the Orbital Space Stations (OSS) while wearing protective space suits (SS). When the International Space Station 'Alpha' (ISSA) is fully operational, EVA assembly, installation, maintenance and repair operations will become an everyday repetitive work activity in space. It needs new ergonomic evaluation of the work/rest schedule for an increasing of the labor amount per EVA hour. The metabolism assessment is a helpful method to control the productivity of the EVA astronaut and to optimize the work/rest regime. Three following methods were used in Russia to estimate real-time metabolic rates during EVA: 1. Oxygen consumption, computed from the pressure drop in a high pressure bottle per unit time (with actual thermodynamic oxygen properties under high pressure and oxygen leakage taken into account). 2. Carbon dioxide production, computed from CO2 concentration at the contaminant control cartridge and gas flow rate in the life support subsystem closed loop (nominal mode) or gas leakage in the SS open loop (emergency mode). 3. Heat removal, computed from the difference between the temperatures of coolant water or gas and its flow rate in a unit of time (with assumed humidity and wet oxygen state taken into account). Comparison of heat removal values with metabolic rates enables us to determine the thermal balance during an operative medical control of EVA at "Salyut-6", "Salyut-7" and "Mir" OSS. Complex analysis of metabolism, body temperature and heat rate supports a differential diagnosis between emotional and thermal components of stress during EVA. It gives a prognosis of human homeostasis during EVA. Available information has been acquired into an EVA data base which is an effective tool for ergonomical optimization.

Adult↗
PubMed2002

Myocardial infarction risk and occupational categories in Kaunas 25-64 year old men.

AIMS: To investigate the risk of a first time myocardial infarction (MI) among different occupational categories in 25-64 year old men in Kaunas, Lithuania, a country in a transition market economy. METHODS: Case-control study among men aged 25-64 who were residents in Kaunas between 1997 and 2000. First time, non-fatal MI cases (n = 448) were identified from the MI hospital register (International Classification of Diseases, 10th revision, code I21). Controls (n = 1777) were selected and matched on age, gender, and city district of residence. Information was obtained on occupation, smoking, hypertension, psychosocial, and behavioural factors. The International Standard Classification of Occupations (ISCO) was used to code for occupational categories. The relation between MI and occupational categories was evaluated by logistic regression analysis, adjusting for a number of selected risk factors. RESULTS: Legislators, senior officials, and managers (1st ISCO category) had a twofold increased risk for MI compared to craft and related trades workers (7th ISCO category) after adjustment for age, district, smoking, hypertension, obesity, stress, education, and employment duration. An increased risk for professionals (2nd ISCO category) and plant and machine operators and assemblers (8th ISCO category) was also observed. Employment duration in the last occupation for 20 years and more almost doubled the risk of MI in the whole population. We also found an increased risk for other traditional IHD risk factors such as smoking and arterial hypertension. CONCLUSIONS: Differences in first time MI risk among occupational categories were found. Legislators, senior officials, and managers (1st ISCO category), professionals (2nd ISCO category), and plant and machine operators and assemblers (8th ISCO category) were at an increased risk. Differences in psychosocial factors in transition market economy countries may contribute to observed results.

Adult↗