Stresses

Rolling bearings are well precision, few cost but large amount used in all kinds of rotary machine. It takes long time for the human being to develop the bearing from the initial idea to the modern rolling bearing. The reason why bearing is used is that first it can transfer moment or force. Secondly and maybe more important is that it can be interchanged easily and conveniently when it's broken. In today's world maintenance of any machinery is very important in view of downtime of machinery. The bearing sector is one of the examples without which no single rotating machinery work. Production of bearing industries are of high value which leads to the aspects of bearing life & application in more demanding situations.

This research presents the design and performance test of stair climbing trolley. The aim of this project is developing a mechanism for easy transportation of heavy loads over stairs. The need for such a system arises from day-today requirements in our society. In this research, shaft diameter is calculated by using bending strength of the beam. Mild steel shaft is selected for design to obtain high strength. The length of shaft is 21 in and the calculated diameter of shaft is 0.75 in. Bearing No: 204 of single row angular contact ball bearing is selected. The design is based on the bearing that can be only efficient for 60 kg load with the speed of the normal human.

Conventional transmission system using single plate clutch has to perform 15 operations to shift from low speed to high speed, out of the 10 operations are clutch operations. Hence making clutch operations automatic will reduce human effort. The auto-disengagement single clutch employs only one set of compression springs instead of the usual two sets, with this arrangement it is possible to reduce the weights of the centrifugal members. This arrangement keeps the clutch in normally disengaged condition unlike the conventional clutch that is in engaged condition and has to be disengaged by manual Lever. In transmitting power from engine to gearbox, Clutch plate plays an important role. So in this paper we designed a single plate clutch by using empirical formulae. By using CATIA V5 we have created a model of single plate clutch and then imported in ANSYS workbench for analysis. We have conducted static structural analysis of clutch base and its friction plate with lining material as FTL 097. The results are compared for the maximum deformation and stresses.

This research presents the design and performance test of three roll metal bending machine (shaft design). The main purposes of this research are to construct a three roll metal bending machine and to do the performance tests. The aim of this project is to develop a portable metal bending machine to bend sheet into curves and the other curvature shapes. In this research, shaft diameter is calculated by using ASME code equation. Mild steel shaft is selected for design to obtain high strength. The estimated diameter of rotating shaft is 31.75mm and main shaft is 25.4mm. Pillow block bearing UCP205 is selected. The estimated value of Factor of Safety is 3.32. Therefore, the determination of research design is totally safe. As a lot of time is consumed when metal bending is made by hand, so using bending machine will save the waste time. The size of machine is small and it is convenient for portable work. No skill worker is required to operate the machine.

An engine basically is defined as a device which converts chemical energy of the fuel into heat energy and further into mechanical output. Based on classifications there are variety of engines based on the size, position of piston, and farther classification, consideration of various parameters is important so as for the efficient working of an engine. One of them being the heat dissipation. Heat dissipation is an important factor because overheating the engine may not just only reduce its overall performance but may develop thermal stresses, fatigue and over all reduce in the working life cycle of an engine. The paper tries to investigate the thermal distribution of a v8 turbo charge engine block and tries to analyze the cooling effect of air by CFD

The aim of this in vitro study was to evaluate the effect of implant position and edentulous span length on stresses around implants assisting claspless distal extension partial overdentures. Four bilateral mandibular distal extension acrylic models were constructed. Two implants were inserted in the distal extension ridges parallel to each other and perpendicular to the ridges. Based on the implant position, models were categorized into two groups: Group I, mesial implants position and Group II, distal implant position. Each group was subdivided into 2 subgroups according to the length of edentulous span: Subgroup a, long span and Subgroup b, short span. Four claspless partial overdentures were fabricated on the models and retained to the implants with ball-and-socket attachments. Three strain gauges were cemented to the acrylic resin at buccal, lingual, and distal sides of each implant. Static unilateral vertical load of 60N was applied in the central fossae of the first molar, and peri-implant stresses were measured on loading and nonloading sides. Distal implant placements recorded significantly higher peri-implant stresses than did mesial implant placements. Long saddle recorded significantly higher stresses than did short saddle. The greatest peri-implant stresses were recorded with distal placement and long saddle at the loading side. At loading and nonloading sides, the mesial placement with a short saddle recorded the lowest strain. For mandibular distal extension partial overdentures, a mesially placed implant combined with short saddle may be preferable to a distally placed implant combined with long saddle, as the former was associated with reduced peri-implant stresses.

Speed reducer is required in industrial as well as in some other areas such as in Agriculture area .In industrial area Conveyors, Packaging Machinery, Cranes/Hoist/Winches, Mixers/Agitators; lifting devices required the speed reduction. The Speed Reducer is used to maximize the speed reduction ratio. The conventional design of speed reducer is difficult to design and required more space. So that the simple and compact speed reducer which having easy design, easy of assembly and good for manufacturing tolerances is made. The shaft mounted speed reducer input and output shaft are parallel. In this speed reducer Internal gear ring and external gear which is mounted on driving shaft of motor eccentrically known as external wobble gear are used in speed reducer. The speed reduction ration we are getting is 1:14. By using CATIA V5 we have created a model of Internal Gear and External Wobble Gears and then imported in ANSYS workbench for analysis. We have conducted static structural analysis of both the gears by using ANSYS .The values of maximum stresses from structural analysis are compared with theoretical calculation.

The effect of vibration on soil compaction has gained a good reputation when consolidating an artificially improved foundation. The studies aimed at analyzing the effect of the deep vibration on the properties of the compacted water-saturated soil have made it possible to establish that vibration can be an effective means of consolidation speeding-up. Vibration contributes to the emergence of additional excess pressures in the pore water; the filtration rate due to the increased pressure gradient increases as well. Consolidation speeding-up (soil compaction by squeezing out the pore water) is quite relevant. It is clear that consolidation speeding-up of foundation water-saturated soil is extremely important in site preparation for reducing site preparation time up to a period of a short summer. The study focuses on the mechanism of deep vibration (longitudinal mechanical waves) having an effect on water-saturated soil consolidation. The mechanism is based on the changed physical state of the medium and takes into account its structure. Two soil models have been proposed. The first one-parameter soil model is called a “sandwich (layer- cake)”. The second two-parameter soil model is called a "loose sandwich". In here, the first model is a special case of the second one. Both parameters have simple physical significance. The study shows that according to the proposed mechanism, the effect of vibration on soil consolidation is reduced to redistribution of the relationship between the stress in soil skeleton and the pore pressure versus the value of "vibration pressure" in such a way that the pore pressure increases, nevertheless, cannot exceed the value of the external static load. The paper also presents the results of numerical calculations.

Abstract:
This investigation studied the effect of steel fibres on the developed stress in headed bars. One  concrete mix is used with a weight proportions of (1:1.7:3:0.45;cement:sand:gravel and water cement ratio respectively) and gave a minimum cylinder strength of 37.5 MPa. The variables included three bars sizes (10, 12 and 16 mm), embedment depths(50, 55, 60, 65, 95 and 100 mm,) three plane dimensions of a 10 mm thick square steel head (20×20, 25×25 and 30×30 mm) welded to the bars, and the steel fibres volume percentage (0.4,0.8 and 1.2). The steel fibres were of the Harex type with irregular cross section, 16 mm long and an equivalent aspect ratio of 19.64. The test results showed that the developed stress in the bars increased with the embedment depth and with the steel fibres percentage considerably, while the used dimensions of the square steel head does not affect the steel stress significantly. The failure mode of the concrete specimens was sudden and brittle while that of the  fibrous concrete specimens showed a gradual and ductile mode of failure.

This paper presented the structural behaviour of a Submerged Floating Tunnel (SFT) for the Seribu Archipelago crossing under environmental loadings using the different cable configurations. The SFT is a tubular structure submerged in the water at a fixed depth, which features several advantages from the structural, economic and environmental impact points of view. In particular, it seems to be a suitable system for waterway crossings in seismicity zones, because the interaction with the water provides additional damping and inertia to the structural motion. In order to evaluate the SFT structural response to seismic events, response spectrum analyses were carried out considering for a ground multi-support excitation. The different cable system configuration was considered in this investigation. The static and dynamic analyses were carried out to find out the best configuration among them. Although they could not lead to definitive conclusions, the results gave useful indications abo...

Salt stress significantly contributes to major losses in agricultural productivity worldwide. The sustainable approach for salinity-accrued toxicity has been explored. The use of plant growth regulators/phytohormones, mineral nutrients and other signaling molecules is one of the major approaches for reversing salt-induced toxicity in plants. Application of the signaling molecules such as nitric oxide (NO) and ethylene (ETH) and major mineral nutrient such as nitrogen (N) and sulfur (S) play significant roles in combatting the major consequences of salt stress impacts in plants. However, the literature available on gaseous signaling molecules (NO/ETH) or/and mineral nutrients (N/S) stands alone, and major insights into the role of NO or/and ETH along with N and S in plant-tolerance to salt remained unclear. Thus, this review aimed to (a) briefly overview salt stress and highlight salt-induced toxicity, (b) appraise the literature reporting potential mechanisms underlying the role of ...

A shear wall is a structural element used to resist horizontal forces parallel to the plane of the wall. Shear wall has highly in plane stiffness and strength which can be used simultaneously resisted large horizontal loads and support gravity loads. It is very necessary to determine effective, efficient and ideal location of shear wall. Shear wall are specially designed structure walls include in the building to resist horizontal forces that are includes in the plane of the wall due to wind, EQ and other forces. They are mainly a flexural member and usually provided in the high rise building to avoid the total collapse of the high rise building under seismic forces. In this research G+9 storey building is presented with some investigation which is analyzed by changing various location of shear wall for determining the optimum structural configuration of multistory building by changing shear wall location radially by analyzed and designed as a space frame system by computer aided software, subjected to lateral and gravity loading in accordance with IS provisions.

Abstract:  -  Seismic  analysis  of  a  multi-story  RC  frame  in  Khartoum  city  was  analyzed  under  moderate
earthquake loads as an application of seismic hazard,and in accordance with the seismic provisions proposed for
Sudan[1]to  investigate  the  performance  of  existing  buildings  if  exposed  to  seismic  loads.  The  frame  was
analyzed using  the response  spectrum method  to calculate  the seismic displacements and  stresses.The  results
obtained, clearly, showthat  the nodal displacements caused drifts  in excess of  approximately 2  to 3  times  the
allowable  drifts.  The  horizontal motion  has  a  greater  effect  on  the  axial  compression  loads  of  the  exterior
columns compared to the interior columns andthe compressive stresses in ground floor columns were about 1.2
to 2  times  the  tensile  stresses. The values of  shear  forces due  to L/C3  in beams B805, B806 and B807 were
found to be about four times the values due to L/C1.The maximum values of compressive and tensile stresses in
beams  are  approximately  equal.  Bending moments  in  beams  and  columns  due  to  seismic  excitation  showed
much larger values compared to that due to static loads.

Cadmium (Cd) is an environmental toxicant, capable of reducing mitochondrial ATP production and promoting the formation of reactive oxygen species (ROS) with resultant oxidative stress conditions. The ovary and testis are the primary gonads in which female gametes (oocytes) and male gametes (spermatozoa), estrogen and testosterone are produced. These organs are particularly susceptible to Cd cytotoxicity due to their high metabolic activities and high energy demands. In this review, epidemiological and experimental studies examining Cd toxicities in gonads are highlighted together with studies using zinc (Zn), selenium (Se), and natural substances to reduce the effects of Cd on follicular genesis and spermatogenesis. Higher blood concentrations of Cd ([Cd]b) were associated with longer time-to-pregnancy in a prospective cohort study. Cd excretion rate (ECd) as low as 0.8 μg/g creatinine was associated with reduced spermatozoa vitality, while Zn and Se may protect against spermatozoa...

A simulation study of the effect of shear stresses in non-reinforced and reinforced structures was carried in this work. Using the Finite Element Method and equations of elasticity, columns and concrete deck of a simple storey structure were subjected to plane strain conditions. The results showed that proper reinforcement causes stresses to be directed into the reinforcements with the resultant shear stresses in the steel reinforcements far below the yield stresses of the steels. In non-reinforced and insufficiently reinforced members it was observed that stresses were directed into the concrete itself with resultant transverse shear at critical joints of the structure. In the insufficiently reinforced member, the resultant shear of the concrete resulted in load transferred to the reinforcement itself with the resultant buckling of reinforcement and eventual collapse of structure.

We compared the ability of two bacterial strains, Paenibacillus polymyxa A26 and P. polymyxa A26Sfp, for biodegradation of naphthalene (NAP). The studies were performed under simulated laboratory conditions, in liquid medium and soil with different carbon sources, pH and salt contents. Changes in the luminescence inhibition of Aliivibrio fischeri, as an indicator of the baseline toxicity, were observed in degradation mixtures during 7 days of incubation. While both strains expressed the best growth and NAP degradation ability in the minimal salt medium containing sucrose and 5% NaCl at pH 7 and 8, the mutant strain remained effective even under extreme conditions. A26Sfp was found to be an efficient and potentially industrially important polycyclic aromatic hydrocarbon degradation strain. Its extracellular polysaccharide production is 30%, and glucan production is twice that of the wild type A 26. The surface tension reduction ability was ascertained as 25–30% increased emulsificati...