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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Monolithic and composite Li-#alpha#-sialon ceramics

Yu, Zhengbo January 2000 (has links)
No description available.

Reinforcement of concrete elements with modified polymers

Gowripalan, N. January 1987 (has links)
No description available.

Preparation and properties of oriented glass-filled thermoplastics

Curtis, A. C. January 1987 (has links)
No description available.

Laboratory and field studies of the textile reinforcement of earthfills

DuBois, D. D. January 1981 (has links)
No description available.

Sandwich action in foam filled masonry cavity walls

White, Kevin Andrew January 1998 (has links)
No description available.

Neuronal activity related to novelty, familiarity and reinforcement

Wilson, F. A. W. January 1985 (has links)
No description available.

Bonus reinforcement in a sheltered workshop : using a multiple baseline technique

O'Brien, Robert A., 1930- January 1974 (has links)
This thesis explored an applied behavioral analysis of bonus reinforcement in the Henry County Retarded Children’s Association Sheltered Workshop at New Castle, Indiana, using a multiple baseline technique. This technique has particular value when the behavior studied appears irreversible or when reversing is undesirable. Using this technique a number of responses are identified and measured over time, allowing changes to be evaluated.The techniques making up a particular behavioral application must be completely described and identified. Procedural descriptions require considerable detail about all possible contingencies in the experiment. The theoretical importance of a value is not sought after, but rather specifically its power in altering behavior enough to be socially important.A behavioral change may have generality if it proves durable over a period of time, if it appears in a wide variety of different environments, or if it spreads to a wide variety of related behaviors. If it is effective in changing behavior in one setting it may easily be repeated in other settings and thus accomplish generalization.The present study proposed that if a S receives reinforcement in one work situation that the behavior generated will carry over into other work and social situations by generalization.It was concluded from the study using the multiple baseline design that the bonus treatment was effective in increasing production overall and that generalization did occur.

The interaction of deprivation and delay of reinforcement under a fixed ratio schedule of responding

Hilgert, Larry D. January 1975 (has links)
Motivation is an important factor in psychology, and much attention, therefore, has been devoted to the study of drives. Interaction of deprivation (hunger drive) and delay of reinforcement was studied in an operant framework in this experiment.Four male Sprague Dawley rats at approximately 250 days of age served as subjects in this experiment. The rats were exposed to a series of conditions within a counter-balanced design. The four conditions were: (a) 85 percent adjusted body weight with no delay; (b) 85 percent adjusted body weight with a 10 second delay; (a) 75 percent adjusted body weight with no delay; and (d) 75 percent adjusted body weight paired with a 10 second delay of reinforcement.Two major conclusions were made from this study. The independent variables may have individually influenced performance, and interaction between deprivation and a signaled delay also occurred when the two were placed in the same environment. Experimental evidence also suggested that discrimination of the delay was not as accurate at higher levels of deprivation.I would like to thank Gary F. Meunier, PhD., who served as chairman of this thesis committee, for his cooperation and assistance in the completion of this thesis. A special thanks also goes to Jerry Ulman, PhD. and Arno Wittig, PhD., whose advice as committee members was invaluable.

Ergonomi vid armeringsarbeten : En studie om möjliga förbättringar i arbetsmiljön vid armeringsarbeten

Engström, Anders, Gustavsson, Jalmar January 2014 (has links)
Injuries and sick-leave is a common feature for reinforcement workers today. This is mainlydue to the fact that reinforcement work is done in an exposed environment with many stressfactors and highly repetitive work. These operations are often carried out in unsuitableworking positions, these positions creates a major burden on the bones and joints and causesmicro- damages on muscles. With repetitive work these injuries are not given time to healproperly and will gradually become worse.The body will not be able to handle the stress of working in a work environment such as thisand musculoskeletal disorders can be a result of this. The injury will make itself known aspain in the musculoskeletal system and causes reduced movability; the injured worker willtherefore not be able to perform the same work tasks as before. The worst case scenario willbe long sick-leave that result in early retirement of the employee.In the current situation early retirement is something that affects 630 construction workers andthere is nothing to suggest that reinforcement workers would be under-represented in thiscategory, on the contrary. This issue will become worse now that the next generation ofreinforcement workers will have a lower basic physics than those before them. Therefore theyare more sensitive to just stress related injury such as musculoskeletal disorders. That is whyit is important now more than ever to find the problem areas and identify them. Failure to doso can lead to reinforcement workers not being able to work until their full retirement age. Itis in the employees, the company and the state's interest to ensure that all workers are able towork to full retirement age when sick leave results in high costs for all parties.The authors have therefore investigated if the use of precut and bent reinforcement and extraservices improve working conditions in the construction site. The authors have alsoinvestigated how the reinforcement process should be designed to prevent work-relatedinjuries and aids that are available at the workplace. To investigate this, the authors startedwith a literature study that included reinforcement, ergonomics and work-related injuries.When the authors felt that they had a sufficient foundation was Thomas Eriksson at CelsaSteel Service contacted and site visits booked. Workplace observations were carried outaccording to the PATH method with complementary interviews.The authors have concluded that the workplace provides aids so that work can be performedin an ergonomic way. However the reinforcement workers choose themselves to perform thework without the aids provided because they say that some aids slow them down. The authorshave perceived a low level of knowledge about ergonomics among the reinforcement workers,this leads to that the workers don’t consider the consequences of bad ergonomic which resultin improper work execution and work-related injuries. The authors also concluded that ahigher degree of prefabrication of reinforcement used results to improve the workingenvironment, even the use of extra services such as color-marked reinforcement, color-sortedreinforcement and timed deliveries contribute to a better work environment. / Skador och sjukskrivningar är ett vanligt inslag i armeringsmontörer arbetsmiljö. Detta berorfrämst på att armeringsarbeten utförs i en utsatt arbetsmiljö med många belastningsfaktoreroch mycket repetitivt arbete. Dessa arbetsmoment utförs ofta i olämpliga arbetsställningar,ställningarna skapar stora belastningar på skelett och leder samt orsakar mikro skador imusklerna. Vid repetitivt arbete ges inte skadorna tid nog för att läka ordentligt utan förvärrasmed tiden.Vid långvarigt arbete i en arbetsmiljö som detta orkar inte kroppen med, detta gör sig märkthos den skadedrabbade genom smärtor i rörelseorganen. När någon drabbas av enbelastningsskada kan det leda till att montören behöver begränsa sina arbetsuppgifter, i värstafall kan det resultera i långa sjukskrivningar och förtidspension för den anställda.I dagsläget går årligen cirka 630 byggnadsarbetare i förtidspension, det finns inget som tyderpå att armeringsmontörer skulle vara underrepresenterade i denna kategori snarare tvärtom.Nu när nästkommande generation kommer ut i arbetslivet blir det viktigare att finna enlösning på detta problem då denna generation har en 10 % sämre grundfysik än tidigare. Ominte detta görs kan de leda till att inga armeringsmontörer kommer klara av att arbeta tillspensions ålder. Det ligger i den anställda, företaget och statens intresse att se till att alla klararav att arbeta till full pensionsålder då sjukskrivningar och förtidspension leder till högakostnader för samtliga parter.Författarna har därför undersökt om användningen av iläggningsfärdig armering ochmervärdestjänster förbättrar arbetsmiljön på arbetsplatsen, författarna har även undersökt hurarmeringsprocessen bör vara utformad för att undvika arbetskador och om hjälpmedel somfinns tillgängliga på arbetsplatsen används. För att undersöka detta började författarna meden litteraturstudie där de fördjupade sig bland annat i armering, ergonomi och arbetsskador.När författarna ansåg att de hade en tillräcklig grund att stå på kontaktades Thomas Erikssonpå Celsa Steel Service och platsbesök bokades, på arbetsplatserna utfördes observationerenligt PATH metoden med kompletterade interjuver.Författarna har kommit fram till att arbetsplatser tillhandahåller hjälpmedel så att arbetet kanbli utfört på ett ergonomiskt sätt. Dock så väljer montörerna själva att utföra arbetet utan vissahjälpmedel som de anser medför ett långsammare arbetsutförande. Författarna har uppfattaten låg kunskap om ergonomi bland armeringsmontörerna vilket leder till att montörerna tarkonsekvenserna allt för lättsinnigt och som följd uteblir ”korrekt” arbetsutförande. Författarnahar även kommit fram till att desto högre prefabricerings grad av armering som användsförbättras arbetsmiljön för montörerna, även förekomsten av mervärdestjänster bidrar till enförbättrad arbetsmiljö.

Observation of the behavior of rats running to reward and nonreward in an alleyway

Kello, John Edward, 1946- 01 February 2017 (has links)
The first experiment sought specifically to determine whether variations in rats' overall run time in the alleyway reflect variations in the vigor of a single response, running (Hullian S-R view), or variations in the frequency of running relative to other, competing, behaviors, and not in the vigor of running ("response-competition" view). More broadly, the goal was a detailed descriptive account of the alleyway behavior of individual rats under a variety of typical experimental conditions. Six 23-hr. hungry rats were run for 75 trials in an alleyway to various amounts of reward, and the amount was shifted at several stages of training. Also, an environmental stimulus change was introduced during training. Six 23-hr. thirsty rats were run under comparable conditions. Overall run time was recorded and each trial was video-taped. Each run was then classified as a competing behavior trial (subject ceases forward progress after entering alleyway), an accessory behavior trial(subject shows some additional behavior while running forward, but no full competing behavior), or a direct run trial (only running occurs). The primary results were: (1) the decrease in run time in acquisition for each subject was due mainly to an orderly decrease in the amount of competing and accessory behavior, but the vigor of running also increased; (2) large changes in run time with other manipulations (differences in amount of reward in acquisition, shifts in amount of reward, extra stimulus, and proximity to reward) also reflected changes in amount of competing and accessory behavior, and smaller changes in the vigor of running; (3) the behavior of the thirsty rats was qualitatively the same as the behavior of the hungry rats, but was less affected by reward. The thirsty rats ran slower and showed more overall variability and more competing and accessory behavior than the hungry ones. The main implication of these results is that the alleyway is a multiple-response, selective-learning situation in which running both increases in vigor and gradually replaces other behaviors. The second experiment examined the structure of behavior in extinction to determine whether the increase in run time with non-reward reflects a return of competing and accessory behavior in the absence of selection for running. Secondary questions, not critical to a selective-learning view of the alleyway, were: (1) Would the addition of extra stimuli in acquisition which encourages competing behavior delay the return of high levels of competing behavior in extinction? (2) Does partial reinforcement in acquisition, which does retard extinction, do so through an increase in competing behavior in acquisition? Ten 23-hr, hungry rats were run in the alleyway to continuous reward (CRF), continuous reward with extra stimuli (CRF-S), or partial reward (PRF), for 59 trials. All were then run for at least 18 non-rewarded trials in extinction. The primary results were: (1) extinction following continuously rewarded acquisition did reflect a great return of competing and accessory behavior, of the same form as early in acquisition, consistent with the view of the alleyway as a selective-learning situation; (2) CRF-S rats showed slightly greater resistance to extinction than CRF rats; (3) the great resistance to extinction of the PRF rats was not a function of high levels of competing and accessory behavior in acquisition; (4) the PRF subjects showed much competing and accessory behavior and slow running in latter parts of the alleyway, and some continuously rewarded subjects showed similar behavior. This, plus observations in both experiments of recurrent behavior sequences across subjects and periods of atypically long run times for several subjects, suggests that an individual rat's behavior is not entirely independent of the behavior of other subjects run concurrently, though the mechanism underlying these interactions is not understood. / This thesis was digitized as part of a project begun in 2014 to increase the number of Duke psychology theses available online. The digitization project was spearheaded by Ciara Healy.

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