753 research outputs found
Letter from H.K Lewis & Co. LTD to Dr. Alfred E. Cohn
No full textLetter from H.K Lewis & Co. LTD to Dr. Alfred E. Cohn, 1934
Alfred E. Cohn (1879-1957), physician, humanist, author, and bibliophile, was one of the first cardiologists in the United States. He was born in New York City and received an MD from the College of Physicians and Surgeons at Columbia University in 1904. Between 1907 and 1909 he studied in Freiburg, Vienna, and London. When he returned to the United States, Dr. Cohn joined the staff of Mount Sinai Hospital in New York. In 1911, he moved to the Rockefeller Hospital, bringing his electrocardiograph with him. He remained at Rockefeller for the rest of his career, retiring in 1944. Dr. Cohn took a leading role in organizations such as the New York Heart Association, New York Academy of Medicine, Veterans Administration, China Medical Board, Asia Institute, Sydenham Hospital, and the Committee for Displaced Foreign Scholars and Displaced Foreign Physicians.https://digitalcommons.rockefeller.edu/objects-tell-stories/1010/thumbnail.jp
Quantitative analysis of the effects of audio biofeedback on weight-bearing characteristics of persons with transtibial amputation during early prosthetic ambulation
No full textAuthor name used in this publication: Daniel H.K. ChowVersion of RecordPublishedVoR allowe
Electronic detonators - a technological update
No full textDevelopment of electronic detonator is a quantum leap towards digitization of mining industry and viewed as major technological advancement towards safety and productivity. The accuracy, flexibility and reliability offered by electronic detonators have provided blasting engineers with many option to optimize the timing designs for maximum benefits in the areas of ground vibration control and maximized fragmentation.
The paper discusses advancement in the field of initiation system and development of electronic detonator. Emphasis on the field application and safety aspect of electronic detonators vis-à-vis advancement over pyrotechnic composition has been also reviewed
CONTROLLED BLASTING TECHNIQUES FOR DEVELOPMENTOF ROAD INFRASTRUCTURES IN HILLY TERRAIN
Get PDFBlasting is a process of breaking the rock mass to excavate the ore and materials. Many open blasting operations are faced with the apparently conflicting requirements of providing large quantities of fragmented rock and of minimizing the amount of damage inflicted upon the surrounding slopes. A slope in strong hard rock is not necessarily stable, nor is a slope in weathered weak rock necessarily unstable. In some cases the reverse is true, depending on the geometry of joints and weak planes. Many slope failures in hard rock occur with no or very little warning. Detection and monitoring may not be feasible, or require sophisticated instruments and procedures that are not practical at some locations. An important element in avoiding catastrophes is to study the site geology for dangerous conditions, implement the types of blasting procedures that minimize failures, and evaluate the potential use of reinforcement or other mechanical stabilizing procedures. Apart from undesired profile of excavation, the conventional blasting damages the surrounding rock mass and structures like buildings, etc. These damages can be minimized by use of controlled blasting technique. The controlled blasting technique (CBT) is used to produce the desired stability of pit walls/slope. The CBT used for slopes is specifically termed as wall controlled blasting technique (WCBT). WCBT includes buffer blasting, trim blasting, line blasting and pre-splitting. Among these, the pre-splitting is the most commonly used technique. This technique has several advantages such as minimum damage from back-break, enhanced carrying capacity, higher structural stability and stable final pit walls or slope at the designed angle thus improving overall safety of wall/slop
Empirical and probabilistic analysis of blast-induced ground vibrations
No full textAn attempt has been made to include an additional blast design parameter, burden, in obtaining the vector peak particle velocity, VPPV. A large set of about 640 blast data pertaining to different rock types from ten different sites in India and Turkey has been collected from the literature. Analysis of these data has been carried out resulting in the proposal of an empirical model for peak particle velocity with due consideration to the burden along with monitoring distance and maximum charge per delay. The performance of the proposed model has been compared with existing models, and the proposed model has been found to serve the purpose of predicting VPPV with greater accuracy. Further, probabilistic analysis of VPPV has been conducted by performing Monte-Carlo (MC) simulation on proposed empirical model. Typical results corresponding to Chittorgarh limestone mines in India are presented. The input parameters namely monitoring distance and maximum charge per delay have been assumed as lognormally distributed random variables, while the burden has been assumed as discreet variable. The analysis of results of MC simulations revealed that output or the state variable, VPPV follows a lognormal distribution. It was possible to take into account the variability in the blast parameters and therefore to study its influence on VPPV
Delay precision in permitted copper delay detonators
No full textBlasting off-the-solid is the most commonly used method during development of galleries in bord and pillar method of underground coal mining. In this method, only P5 explosives are used with permitted delay detonators in accordance with the safety requirements stipulated by the regulatory bodies. Delay detonators made with pyrotechnic delay compositions have inherent scattering in their delay timings. It is desirable to use precise detonators to achieve better fragmentation, less vibration and noise. Overlapping of delay period is undesirable form production as well as safety point of view.
In order to assess delay accuracy of permitted detonators of a domestic manufacturer, randomly selected fifty nos. of detonators from the same batch of detonators which was found suitable for use in underground coal miens in respect of their incendivity, handling and electrical safety, performance and water resistance characteristics were evaluated. Overlapping possibilities amongst delay periods were evaluated by calculating Winzer index and graphical methods.
The findings reveal that significant scattering exist in all the delay periods. Scattering increases with higher delay periods. Overlapping possibilities between delay period 5 and 6 is found to be significantly high. Winzer index for the pair of delay period 5 and 6 is found to be very close to the threshold value for overlapping
Investigation of Delay Time Precision in Pyrotechnic Detonators
No full textDespite advancement of initiating devices, use of electrical detonators with pyrotechnic composition is common in Indian mining and construction industry. The cost benefit achieved by electrical detonators over shock tube initiation system and electronic detonators is huge. Delay detonators made with pyrotechnic delay compositions have inherent scattering in their delay timings. It is desirable to use precise detonators to achieve better fragmentation, less vibration and noise. Overlapping of delay period is undesirable from production as well as safety point of view.
In order to assess delay accuracy of electrical pyrotechnic detonators of a domestic manufacturer, randomly selected fifty units from each delay period (0 to 6) from the same batch of detonators that were found suitable for use in underground coal mines in respect of their incendivity, handling & electrical safety, performance and water resistance characteristics were evaluated. Overlapping possibilities amongst delay periods were evaluated by calculating Winzer index and graphical methods.
The findings reveal that significant scattering exist in all the delay periods. Scattering increases with higher delay periods. Overlapping possibilities between delay period 5 and 6 is found to be significantly high. Winzer index for the pair of delay period 5 and 6 is found to be very close to the threshold value for overlapping
Multimodal recognition of emotions
No full textThis thesis proposes algorithms and techniques to be used for automatic recognition of six prototypic emotion categories by computer programs, based on the recognition of facial expressions and emotion patterns in voice. Considering the applicability in real-life conditions, the research is carried in the context of devising person independent methods that should be robust to various factors given the specificity of the considered modalities. An immediate focus represents the development of audio-visual algorithms and their implementation in form of software applications for automatic recognition of emotions.MediamaticaElectrical Engineering, Mathematics and Computer Scienc
Mahatma Gandhi and the depressed classes
No full textBiennial Professor H.K. Barpujari endowment lectures(2005-06) delivered by the author at Kolkata during 21-22 February 2006
- …
