59,505 research outputs found
Self-balancing beam permits safe, easy load handling under overhang
The use of a self-balancing I-beam with a counterweight and motor simplifies moving heavy loads that are inaccessible for cranes. The beam cannot be overloaded, as the counterweight will not balance the load, and thus acts as an automatic safety device
Recommended from our members
Do pride and prejudice stand in the way of persuasion? Embracing other disciplines for the advancement of advocacy teaching
This paper considers the importance of advocacy teachers adopting a multi-disciplinary approach to the teaching of advocacy and suggests how this can be acieved
Theoretical and experimental studies of atmospheric structure and dynamics, using high altitude chemical release, Radio meteor, and meteorological rocket network and other data
Data collected by the Georgia Tech Radio Meteor Wind Facility during the fall and winter of 1975 are analyzed indicating a relationship between lower thermospheric circulation at mid latitudes and polar stratospheric dynamics. Techniques of measurement of mixing processes in the upper atmosphere and the interpretation of those measurements are described along with a diffusion simulation program based on the Global Reference Atmosphere program
Reasonableness, Murder, and Modern Science
Originally titled “Is It Murder in Tennessee to Kill a Chimpanzee,” this article argues in some detail that typical legal definitions of “murder” as involving the intentional killing of “a reasonable being” would require classifying the intentional killing of chimpanzees as murder
Filtering device
An electrical filter for removing noise from a voice communications signal is reported; seven sample values of the signal are obtained continuously, updated and subjected to filtering. Filtering is accomplished by adding balanced, with respect to a mid-point sample, spaced pairs of the sampled values, and then multiplying each pair by a selected filter constant. The signal products thus obtained are summed to provide a filtered version of the original signal
Supersonic airplane design optimization method for aerodynamic performance and low sonic boom
This paper presents a new methodology for the optimization of supersonic airplane designs to meet the dual design objectives of low sonic boom and high aerodynamic performance. Two sets of design parameters are used on an existing High Speed Civil Transport (HSCT) configuration to maximize the aerodynamic performance and minimize the sonic boom under the flight track. One set of the parameters perturbs the camber line of the wing sections to maximize the lift-over-drag ratio (L/D). A preliminary optimization run yielded a 3.75 percent improvement in L/D over a baseline low-boom configuration. The other set of parameters modifies the fuselage area to achieve a target F-function. Starting from an initial configuration with strong bow, wing, and tail shocks, a modified design with a flat-top signature is obtained. The methods presented can easily incorporate other design variables and objective functions. Extensions to the present capability in progress are described
The relevance of specific csfs for stakeholders during ERP implementation: an empirical study from Oman
The success of ERP systems implementation is affected by the extent to which stakeholders have been prepared for the project activities and its outcomes. Stakeholders’ preparation needs change as the ERP implementation lifecycle progresses and varies across stakeholder groups. Therefore a dynamic model is needed for such preparation. However such a model needs to reflect the relevance of different CSFs to different stakeholder groups at different stages of the ERP implementation life-cycle. This study examines empirical evidence from a survey conducted in Omani organisations to determine what these individual CSFs are and how they are distributed across the ERP implementation life-cycle for different stakeholder groups. The CSFs included in the survey were derived from a structured review of literature. Purposive sampling was used to select respondents representing different ERP stakeholders groups, all respondents had both experience and knowledge of ERP implementations. The survey data are analysed and the distribution of relevant CSFs across the ERP lifecycle for the different stakeholder groups are presente
Theory of polyzwitterion conformations
Conformational characteristics of polyzwitterionic molecules in aqueous
solutions are investigated using the variational method. Analytical relations
are derived for the radius of gyration of a single polyzwitterionic chain as a
function of the chain length, electrostatic interaction strength, added salt
concentration, dipole moment and degree of ionization of the zwitterionic
monomers. In the absence of the small ions (counterions and coions) near the
polyzwitterionic chain, attractive dipole-dipole interactions are shown to
induce a collapse of the polyzwitterionic chain. However, in the presence of
the small ions, the radius of gyration is shown to be an interplay of the
screening of the electrostatic interactions and the counterion adsorption on
the zwitterionic sites. In addition to the well-known Debye-Huckel screening of
the charge-charge interactions, screening of the charge-dipole and
dipole-dipole interactions are found to play important roles in determining the
size of the chain. Functional forms for the screened charge-dipole and
dipole-dipole interaction potentials are presented. Furthermore, counterion
adsorption on the zwitterionic monomers is predicted to be asymmetric depending
on the nature of the added salt and the zwitterionic groups. Qualitative
remarks regarding the solubility of these molecules in aqueous solutions along
with the classical "anti-polyelectrolyte" effect (increase in the solubility in
water with the addition of salt) are presented.Comment: To be appeared in J. Chem. Phy
Theoretical and experimental investigations of upper atmosphere dynamics
A brief overview of the significant contributions made to the understanding of the dynamics of the Earth's upper atmosphere is presented, including the addition of winds and diffusion to the semi-empirical Global Reference Atmospheric Model developed for the design phase of the Space Shuttle, reviews of turbulence in the lower thermosphere, the dynamics of the equatorial mesopause, stratospheric warming effects on mesopause level dynamics, and the relevance of these studies to the proposed Middle Atmosphere Program (1982-85). A chronological bibliography, with abstracts of all papers published, is also included
- …