Abstract: A new tool path planning method for 5-axis flank
milling of a globoidal indexing cam is developed in this paper. The
globoidal indexing cam is a practical transmission mechanism due
to its high transmission speed, accuracy and dynamic performance.
Machining the cam profile is a complex and precise task. The profile
surface of the globoidal cam is generated by the conjugate contact
motion of the roller. The generated complex profile surface is usually
machined by 5-axis point-milling method. The point-milling method
is time-consuming compared with flank milling. The tool path for
5-axis flank milling of globoidal cam is developed to improve the
cutting efficiency. The flank milling tool path is globally optimized
according to the minimum zone criterion, and high accuracy is
guaranteed. The computational example and cutting simulation finally
validate the developed method.
Abstract: In this paper, application of Sliding Mode Control (SMC) technique for an Active Magnetic Bearing (AMB) system with varying rotor speed is considered. The gyroscopic effect and mass imbalance inherited in the system is proportional to rotor speed in which this nonlinearity effect causes high system instability as the rotor speed increases. Transformation of the AMB dynamic model into regular system shows that these gyroscopic effect and imbalance lie in the mismatched part of the system. A H2-based sliding surface is designed which bound the mismatched parts. The solution of the surface parameter is obtained using Linear Matrix Inequality (LMI). The performance of the controller applied to the AMB model is demonstrated through simulation works under various system conditions.
Abstract: The effect of plant growth-promoting rhizobacteria
(PGPR) on seed germination, seedling growth and yield of field
grown maize were evaluated in three experiments. In these
experiments six bacterial strains include P.putida strain R-168,
P.fluorescens strain R-93, P.fluorescens DSM 50090, P.putida
DSM291, A.lipoferum DSM 1691, A.brasilense DSM 1690 were
used. Results of first study showed seed Inoculation significantly
enhanced seed germination and seedling vigour of maize. In second
experiment, leaf and shoot dry weight and also leaf surface area
significantly were increased by bacterial inoculation in both sterile
and non-sterile soil. The results showed that inoculation with
bacterial treatments had a more stimulating effect on growth and
development of plants in nonsterile than sterile soil. In the third
experiment, Inoculation of maize seeds with all bacterial strains
significantly increased plant height, 100 seed weight, number of seed
per ear and leaf area .The results also showed significant increase in
ear and shoot dry weight of maize.
Abstract: Production of hard-to-cut materials with uncoated carbide cutting tools in turning, not only cause tool life reduction but also, impairs the product surface roughness. In this paper, influence of hot machining method were studied and presented in two cases. Case1-Workpiece surface roughness quality with constant cutting parameter and 300 ºC initial workpiece surface temperature. Case 2- Tool temperature variation when cutting with two speeds 78.5 (m/min) and 51 (m/min). The workpiece material and tool used in this study were AISI 1060 steel (45HRC) and uncoated carbide TNNM 120408-SP10(SANDVIK Coromant) respectively. A gas flam heating source was used to preheating of the workpiece surface up to 300 ºC, causing reduction of yield stress about 15%. Results obtained experimentally, show that the method used can considerably improved surface quality of the workpiece.
Abstract: Two species of Physalis, P.angulataL. and P.
peruviana L. were used as models for comparative study to
understand the values of micro-morphological, -anatomical and
architectural characteristics of leaf for taxonomic purposes and
possibly breeding and commercial applications. Both speciespossess
amphistomaticleaves with 1-layer epidermis, 3-4-layer spongy
mesophyll andbicollateral bundle midrib. Palisade parenchyma cells
of P. angulatawere almost twice longer (65-75 μm) than the other
one. Type of stomata was similar as anomocyticbut stomatal
index(SI) at adaxial surface and abaxial surface of P. angulata were
less than of P. peruvianaas 3.57, 4.00 and6.25, 6.66 respectively.
Some leaf architectural characteristics such as leaf shape, order of
venationalsoprovided information of taxonomic significance
Abstract: The purpose of this work is to present the potential of
solar energy in Zarqa region. The solar radiation along year 2009 was
obtained from Pyranometer which measures the global radiation over
horizontal surfaces. Solar data in several different forms, over period
of 5 minutes, hour-by-hour, daily and monthly data radiation have
been presented. Briefly, the yearly global solar radiation in Zarqa is
7297.5 MJ/m2 (2027 kWh/m²) and the average annual solar radiation
per day is 20 MJ/m2 (5.5 Kwh/m2). More specifically, the average
annual solar radiation per day is 12.9 MJ/m2 (3.57 Kwh/m2) in winter
and 25 MJ/m2 (7 Kwh/m2) in summer.
Abstract: This paper presents a novel three-phase utility
frequency to high frequency soft switching power conversion circuit
with dual mode pulse width modulation and pulse density modulation
for high power induction heating applications as melting of steel and
non ferrous metals, annealing of metals, surface hardening of steel
and cast iron work pieces and hot water producers, steamers and
super heated steamers. This high frequency power conversion circuit
can operate from three-phase systems to produce high current for
high power induction heating applications under the principles of
ZVS and it can regulate its ac output power from the rated value to a
low power level. A dual mode modulation control scheme based on
high frequency PWM in synchronization with the utility frequency
positive and negative half cycles for the proposed high frequency
conversion circuit and utility frequency pulse density modulation is
produced to extend its soft switching operating range for wide ac
output power regulation. A dual packs heat exchanger assembly is
designed to be used in consumer and industrial fluid pipeline systems
and it is proved to be suitable for the hot water, steam and super
heated steam producers. Experiment and simulation results are given
in this paper to verify the operation principles of the proposed ac
conversion circuit and to evaluate its power regulation and
conversion efficiency. Also, the paper presents a mutual coupling
model of the induction heating load instead of equivalent transformer
circuit model.
Abstract: Homogeneous composites of alumina and zirconia
with a small amount of MgO (99%) were obtained for ZTA ceramic containing 0.05 wt% MgO in
1500 °C.
Abstract: Use of microemulsion in enhanced oil recovery has become more attractive in recent years because of its high level of extraction efficiency. Experimental investigations have been made on characterization of microemulsions of oil-brinesurfactant/ cosurfactant system for its use in enhanced oil recovery (EOR). Sodium dodecyl sulfate, propan-1-ol and heptane were selected as surfactant, cosurfactant and oil respectively for preparation of microemulsion. The effects of salinity on the relative phase volumes and solubilization parameters have also been studied. As salinity changes from low to high value, phase transition takes place from Winsor I to Winsor II via Winsor III. Suitable microemulsion composition has been selected based on its stability and ability to reduce interfacial tension. A series of flooding experiments have been performed using the selected microemulsion. The flooding experiments were performed in a core flooding apparatus using uniform sand pack. The core holder was tightly packed with uniform sands (60-100 mesh) and saturated with brines of different salinities. It was flooded with the brine at 25 psig and the absolute permeability was calculated from the flow rate of the through sand pack. The sand pack was then flooded with the crude oil at 800 psig to irreducible water saturation. The initial water saturation was determined on the basis of mass balance. Waterflooding was conducted by placing the coreholder horizontally at a constant injection pressure at 200 pisg. After water flooding, when water-cut reached above 95%, around 0.5 pore volume (PV) of the above microemulsion slug was injected followed by chasing water. The experiments were repeated using different composition of microemulsion slug. The additional recoveries were calculated by material balance. Encouraging results with additional recovery more than 20% of original oil in place above the conventional water flooding have been observed.
Abstract: When considering the development of constitutive
equations describing the behavior of materials under cyclic plastic
strains, different kinds of formulations can be adopted. The primary
intention of this study is to develop computer programming of
plasticity models to accurately predict the life of engineering
components. For this purpose, the energy or cyclic strain is computed
in multi-surface plasticity models in non-proportional loading and to
present their procedures and codes results.
Abstract: One of the most important parameters to develop and
manage urban areas is appropriate selection of land surface to
develop green spaces in these areas. In this study, in order to identify
the most appropriate sites and areas cultivated for ornamental species
in Jiroft, Landsat Enhanced Thematic Mapper Plus (ETM+) images
due to extract the most important effective climatic and adaphic
parameters for growth ornamental species were used. After geometric
and atmospheric corrections applied, to enhance accuracy of multi
spectral (XS) bands, the fusion of Landsat XS bands by IRS-1D
panchromatic band (PAN) was performed. After field sampling to
evaluate the correlation between different factors in surface soil
sampling location and different bands digital number (DN) of ETM+
sensor on the same points, correlation tables formed using the best
computational model and the map of physical and chemical
parameters of soil was produced. Then the accuracy of them was
investigated by using kappa coefficient. Finally, according to
produced maps, the best areas for cultivation of recommended
species were introduced.
Abstract: Occurrences of spurious crests on the troughs of large,
relatively steep second-order Stokes waves are anomalous and not an
inherent characteristic of real waves. Here, the effects of such
occurrences on the statistics described by the standard second-order
stochastic model are examined theoretically and by way of
simulations. Theoretical results and simulations indicate that when
spurious occurrences are sufficiently large, the standard model leads
to physically unrealistic surface features and inaccuracies in the
statistics of various surface features, in particular, the troughs and
thus zero-crossing heights of large waves. Whereas inaccuracies can
be fairly noticeable for long-crested waves in both deep and
shallower depths, they tend to become relatively insignificant in
directional waves.
Abstract: For decades, the defense business has been plagued by
not having a reliable, deterministic method to know when the Kalman
filter solution for passive ranging application is reliable for use by the
fighter pilot. This has made it hard to accurately assess when the
ranging solution can be used for situation awareness and weapons
use. To date, we have used ad hoc rules-of-thumb to assess when we
think the estimate of the Kalman filter standard deviation on range is
reliable. A reliable algorithm has been developed at BAE Systems
Electronics & Integrated Solutions that monitors the Kalman gain
matrix elements – and a patent is pending. The “settling" of the gain
matrix elements relates directly to when we can assess the time when
the passive ranging solution is within the 10 percent-of-truth value.
The focus of the paper is on surface-based passive ranging – but the
method is applicable to airborne targets as well.
Abstract: A registration framework for image-guided robotic
surgery is proposed for three emergency neurosurgical procedures,
namely Intracranial Pressure (ICP) Monitoring, External Ventricular
Drainage (EVD) and evacuation of a Chronic Subdural Haematoma
(CSDH). The registration paradigm uses CT and white light as
modalities. This paper presents two simulation studies for a
preliminary evaluation of the registration protocol: (1) The loci of the
Target Registration Error (TRE) in the patient-s axial, coronal and
sagittal views were simulated based on a Fiducial Localisation Error
(FLE) of 5 mm and (2) Simulation of the actual framework using
projected views from a surface rendered CT model to represent white
light images of the patient. Craniofacial features were employed as
the registration basis to map the CT space onto the simulated
intraoperative space. Photogrammetry experiments on an artificial
skull were also performed to benchmark the results obtained from the
second simulation. The results of both simulations show that the
proposed protocol can provide a 5mm accuracy for these
neurosurgical procedures.
Abstract: This work deals with problems of tool axis inclination angles in ball-end milling. Tool axis inclination angle contributes to improvement of functional surface properties (surface integrity - surface roughness, residual stress, micro hardness, etc.), decreasing cutting forces and improving production. By milling with ball-end milling tool, using standard way of cutting, when work piece and cutting tool contain right angle, we have zero cutting speed on edge. At this point cutting tool only pushes material into the work piece. Here we can observe the following undesirable effects - chip contraction, increasing of cutting temperature, increasing vibrations or creation of built-up edge. These effects have negative results – low quality of surface and decreasing of tool life (in the worse case even it is pinching out). These effects can be eliminated with the tilt of cutting tool or tilt of work piece.
Abstract: Although the STL (stereo lithography) file format is
widely used as a de facto industry standard in the rapid prototyping
industry due to its simplicity and ability to tessellation of almost all
surfaces, but there are always some defects and shortcoming in their
usage, which many of them are difficult to correct manually. In
processing the complex models, size of the file and its defects grow
extremely, therefore, correcting STL files become difficult. In this
paper through optimizing the exiting algorithms, size of the files and
memory usage of computers to process them will be reduced. In spite
of type and extent of the errors in STL files, the tail-to-head
searching method and analysis of the nearest distance between tails
and heads techniques were used. As a result STL models sliced
rapidly, and fully closed contours produced effectively and errorless.
Abstract: This study presents a systematic analysis of wetted region due to cooling of aluminum plate by water spray impingement with respect to different water flow rates, spray nozzle heights, and subcooling. Unlike jet impingement, the wetting is not commenced upon spray impingement and there is a delay in wetness of hot test surface. After initiation, the wetting (black zone) progresses gradually to cover all test plate and provides efficient cooling in nucleate boiling regime. Generally, spray cooling is found function of spray flow rate, spray-to-surface distance and water subcooling. Wetting delay is decreasing by increasing of spray flow rate until spray impact area is not become bigger that test surface. Otherwise, higher spray flow rate is not practically accelerated start of wetting. Very fast wetting due to spray cooling can be obtained by dense spray (high floe rate) discharged from adjacent nozzle to the test surface. Highly subcooling water spray also triggers earlier wetting of hot aluminum plate.
Abstract: Scale defects are common surface defects in hot steel rolling. The modelling of such defects is problematic and their causes are not straightforward. In this study, we investigated genetic algorithms in search for a mathematical solution to scale formation. For this research, a high-dimensional data set from hot steel rolling process was gathered. The synchronisation of the variables as well as the allocation of the measurements made on the steel strip were solved before the modelling phase.
Abstract: A major challenge in biomaterials research is the
regulation of protein adsorption which is a key factor for controlling
the subsequent cell adhesion at implant surfaces. The aim of the
present study was to control the adsorption of fibronectin (FN) and
the attachment of MG-63 osteoblasts with an electronic
nanostructure. Shallow doping line lattices with a period of 260 nm
were produced for this purpose by implantation of phosphorous in
silicon wafers. Protein coverage was determined after incubating the
substrate with FN by means of an immunostaining procedure and the
measurement of the fluorescence intensity with a TECAN analyzer.
We observed an increased amount of adsorbed FN on the
nanostructure compared to control substrates. MG-63 osteoblasts
were cultivated for 24h on FN-incubated substrates and their
morphology was assessed by SEM. Preferred orientation and
elongation of the cells in direction of the doping lattice lines was
observed on FN-coated nanostructures.
Abstract: Most of the drugs used for pharmaceutical purposes
are poorly water-soluble drugs. About 40% of all newly discovered
drugs are lipophilic and the numbers of lipophilic drugs seem to
increase more and more. Drug delivery systems such as
nanoparticles, micelles or liposomes are applied to improve their
solubility and thus their bioavailability. Besides various techniques of
solubilization, oil-in-water emulsions are often used to incorporate
lipophilic drugs into the oil phase. To stabilize emulsions surface
active substances (surfactants) are generally used. An alternative
method to avoid the application of surfactants was of great interest.
One possibility is to develop O/W-emulsion without any addition of
surface active agents or the so called “surfactant-free emulsion or
SFE”. The aim of this study was to develop and characterize SFE as a
drug carrier by varying the production conditions. Lidocaine base
was used as a model drug. The injection method was developed.
Effects of ultrasound as well as of temperature on the properties of
the emulsion were studied. Particle sizes and release were
determined. The long-term stability up to 30 days was performed.
The results showed that the surfactant-free O/W emulsions with
pharmaceutical oil as drug carrier can be produced.