Abundance of low energy (50-150 MeV) antiprotons in cosmic rays

The progress is presented of the nuclear emulsion experiment to determine abundance of low energy antiprotons in cosmic rays. No antiprotons have been detected so far at upper limit of p/p less than or similar to 4 x .0001 in the energy range 50 MeV to 15 MeV

Vacancy-mediated mechanism of nitrogen substitution in carbon nanotubes

Nitrogen substitution reaction in a graphene sheet and carbon nanotubes of different diameter are investigated using the generalized tight-binding molecular dynamics method. The formation of a vacancy in curved graphene sheet or a carbon nanotube is found to cause a curvature dependent local reconstruction of the surface. Our simulations and analysis show that vacancy mediated N substitution (rather than N chemisorption) is favored on the surface of nanotubes with diameter larger than 8 nm. This predicted value of the critical minimum diameter for N incorporation is confirmed by experimental results presented on nitrogen-doped multiwalled nanotubes with [approximate]5 at. % nitrogen prepared by the thermal chemical vapor deposition process

Tests on light gage steel diaphragms

This report supplements and extends the scope of Report No. 319, ;lStructural Performance of Light Gage Steel Diaphragms , by Dr. Larry D. Luttrell. Eleven static load tests were conducted on 22 gage narrow rib roof decks to investigate the effect of length of the diaphragm, type of welding, and diaphragm material tensile properties on the shear stiffness and strength of the diaphragm. The behavior of a diaphragm under reversed load at two different levels) one at 0.4 x ultimate static load and the other at 0.6 x ultimate static load was explored by conducting five tests. The tests at a high level of reversed load (0.6 x Pu) were motivated by the fact that during earthquakes and blasts structures are subjected to high levels of reversed load for a few cycles. Three static load tests were performed on standard corrugated diaphragms to supplement the tests done by Dr. Luttrell and reported in Report No. 319 so as to formulate the strength (Plf.) of a diaphragm without intermediate fasteners* as a function of its thickness. It is confirmed by the above investigations that the shear stiffness of a diaphragm is dependent mainly on the length of the diaphragm, and the type and spacing of fasteners. The strength of a diaphragm is seen to be dependent mainly on the thickness of the diaphragm, and the type and spacing of the • The definition is the same as in Report 319. fasteners. Five cycles of reversed load at +0.6 x ultimate load of an identical diaphragm under static load resulted in a maximum reduction of 25% in strength of the diaphragm

Design of I-shaped beams and columns with diaphragm bracing

Cold-formed steel panels often are used as wall sheathing, roof decking or floor decking in steel framed buildings or pre-engineered metal buildings. Diaphragms formed by interconnecting these panels have considerable in-plane shear resistance, and can be utilized as bracing against buckling for individual members of a steel frame. For wall columns the diaphragm may be either directly attached or connected to girts which in turn are connected to the columns. A procedure is presented for the design of I-section beams and columns with diaphragm or diaphragm-girt bracing. The procedure is based on the ultimate load capacity of fully braced members, utilizing a conservative estimate of the shear strength and shear rigidity of the diaphragm. Design examples are included. The utilization of existing wall, floor or roof diaphragms as bracing for individual beams and columns can eliminate the need for other types of bracing, and/or reduce required member sizes. Thus it contributes to economical design

In situ CCVD synthesis of carbon nanotubes within a commercial ceramic foam

Consolidated nanocomposite foams containing a large quantity of carbon nanotubes (CNTs) within millimetre-sized pores are prepared for the first time. A commercial ceramic foam is impregnated by a 60 g L21 slurry of a (Mg(12x)(Co0.75Mo0.25)xO solid solution (x = 0.01, 0.05, 0.1 and 0.2) powder in ethanol. Three successive impregnations led to deposits several tens of mm thick, with a good coverage of the commercial-ceramic pore walls but without closing the pores. The materials were submitted to a CCVD treatment in H2–CH4 atmosphere in order to synthesise the CNTs. When using attrition-milled powders, the carbon is mostly in the form of nanofibres or disordered carbon rather than CNTs. Using non-milled powders produces a less-compact deposit of catalytic material with a higher adherence to the walls of the ceramic foam. After CCVD, the carbon is mostly in the form of high-quality CNTs, as when using powder beds, their quantity being 2.5 times higher. The so-obtained consolidated nanocomposite materials show a multi-scale pore structuration

Design recommendations for diaphragm-braced beams, columns and wall-studs

INTRODUCTION Light gage steel panels are often used as wall sheathing, roof decking or floor covering in steel framed buildings. These panels carry loads normal to their plane by virtue of their bending strength. Also, diaphragms formed by interconnecting such panels can resist shear deformation in their plane. Because of this shear resisting capacity, diaphragms can be very effective in bracing columns and beams of a steel frame against lateral buckling and, thus, increase the load carrying capacity of these members. For wall columns, such diaphragm bracing may be either directly attached or connected to girts which in turn are connected to the columns. The ribs of the panels must be perpendicular to the members to which they are attached. These diaphragms as wall, roof or floor, must be present in any event, and therefore, are available at no extra cost. If properly utilized for bracing, they can lead to economical design of beams and columns. Research has been conducted at Cornell University since 1961* (1),(2),(3) to determine the increased load carrying capacities of beams and columns due to diaphragm or diaphragmgirt bracing. Based on the results of the investigation to date, recommendations are made in this report for the design of beams and columns considering the effect of diaphragm braci~g. * Superscripts in parentheses refer to the numbers in the References. Design criteria are given in Part 2; the general design procedure in Part 3, and the specific design formulae in Part 4 are illustrated by some practical examples in Part 5. The design procedure suggested herein is based on the ultimate load capacity of the beams or columns, utilizing a conservative estimate of the strength and rigidity of the diaphragm bracing. Effectiveness of diaphragm bracing or diaphragm-girt bracing in preventing lateral buckling of beams and columns depends on its two fundamental characteristics: (1) rigidity, and (2) strength. In general, it is not economical to provide anything less than fUll bracing, where full bracing is defined as bracing such that any increase in rigidity or strength of diaphragm will not cause any substantial increase in the load carrying capacity of the braced members. Therefore, the design procedure in this report is limited to only fullyli braced beams and columns. The procedure is based on analyses of I-section beams under uniform moment, and I-section columns under axial load. These analyses have been substantiated by tests of thirtyfive diaphragm-braced assemblies as reported in the references. Information regarding the load carrying capacities of beams and columns with less than full bracing can be obtained from Reference 3. The capacity of channel and Z-section beams SUbjected to uniform moment also is discussed in Reference 3. Cantilever beams and channel and Z-section beams subjected to loads in the plane of the web are currently under investigation. Light wall studs braced by wallboard on one or both faces are no different basically from columns braced by light steel diaphragms. In order to make the methods developed here applicable to such wall studs, the Appendix gives a few typical test values for diaphragm rigidity and strength of customary types of wallboard

Defluoridation technology based on activated alumina

In this paper the experiments related to the development of defluoridation unit at domestic level for a 3 mg/1 flouride water, using activated alumina are presented in detail. The design and other specifications of the defluoridation unit are given. Details regarding the field studies in a fluorosis - affected village nearby Gandhigram are also discussed

INFLUENCE OF STABILIZATION EXERCISES ON ARTICULAR CARTILAGE CHANGES IN DEGENERATIVE TIBIO- FEMORAL JOINT DISEASE- A PILOT STUDY

Objectives: To determine the effectiveness of knee joint stabilization exercises in minimizing articular cartilage degeneration and to examine theeffectiveness of knee joint stabilization exercises on decreasing pain, improving range of motion (ROM) and muscle strength.Methods: About 20 volunteer subjects (age 35-65 years) with primary osteoarthritis fulfilled the inclusion criteria given the knee stabilizationexercises for 8 weeks. Pain, muscle strength, functional outcome score, and serum cartilage oligomeric matrix protein (COMP) values were measuredpre- and post-intervention using visual analog scale, dynamometer, and ELISA test. Data were analyzed using a paired t-test with Statistical Packagefor the Social Sciences version 20 to find out the difference between the pre- and post-test.Results: The results of the study have shown that significant difference between pre- and post-test values of pain, ROM, muscle strength and functionaloutcome score with p<0.05, and there is statistical in significance in serum COMP value (p<0.05).Conclusion: Stabilization exercises of knee joint were shown to be beneficial for decreasing pain, improving ROM and muscle strength, and there wasno effect on articular cartilage changes in degenerative tibiofemoral joint disease.Keywords: Serum cartilage oligomeric matrix protein, Knee stabilization exercises, Proprioception exercises, Muscle strength. Â

Impact of oxygen plasma treatment on carrier transport and molecular adsorption in graphene

Impact of plasma treatment on graphene\u27s transport properties and interaction with gas molecules has been investigated with Raman, X-ray photoelectron spectroscopy, and Hall measurements. Experimental results indicate the formation of nanocrystalline domains and the enhanced fraction of adsorbed oxygen following oxygen plasma treatment, which correlates with a significant reduction in carrier mobility and an increase in carrier density. The oxygen plasma treated graphene was found to exhibit much stronger sensitivity toward NH3 molecules both in terms of magnitude and response rate, attributable to increased domain edges and oxygen adsorption related enhancement in p-type doping. The carrier mobility in plasma exposed graphene was modeled considering both ionized impurity and short-range scattering, which matched well with the experimentally observed mobility