Drum Surface Research Articles

A study of pinna effect on head‐related transfer functions

For the sound localization, an interaural difference is important. To obtain the desired localization, it is necessary to use a head‐related transfer function (refer to HRTF), which is defined as the transfer function between a sound source and a surface of the ear drum. In our previous work, as far as in the case of reproducing the virtual sound source in the horizontal plane, it is confirmed to be capable of remarkable localization by using the numeric data calculated by a rigid sphere head model instead of a dummy head microphone. However, it is necessary to solve the problem of the front back confusion and the sound localization of the vertical plane. For that, it might be essential to add the pinna information to the rigid sphere model, to examine how each part of the pinna is related to the localization.

Iatrogenic cholesteatoma in children with OME in a training program

To report the occurrence of cholesteatoma following myringotomy and insertion of ventilating tube (VT) in a residency training program. Nine hundred and eighty-four children who were operated for grommet insertion with or without adenotonsillectomy during the year 1999-2003 were included in the study. Children were divided into two groups: group 1 (648 children) operated by residents and group 2 (305 children) operated by consultant. All procedures were carried out under general anesthesia using Ziess operating microscope. Shah ventilating tubes were used in most cases and Goody T tube in some others. Nine ears developed cholesteatoma, six with perforation and three with pearl cholesteatoma cyst and intact tympanic membrane. The rate of iatrogenic cholesteatoma occurrence was 0.62% when done by residents (group 1) and 0.33% when operated by consultants (group 2). The overall prevalence was 0.48%. Iatrogenic cholesteatoma occuring as a complication following VT insertion is not uncommon. It occurs more often following surgery done by inexperienced surgeons. Excessive manipulation may cause meatal wall and drum surface epithelium injury. This epithelium might be pushed with the VT into the middle ear.

Magnetic System With “Antiradial” Magnetization

It is known that the effective work of drum-type magnetic separators is determined only by those forces which act in the radial direction, since strongly keeping magnetic mix on the drum surface with their transportation to the output of magnetic product. The disadvantage of this magnet system is the insufficient value of the magnetic force component of field which acts on the magnetic particles in the direction of their precipitation on the drum surface. This system is used for slight magnet particles precipitation. Mathematical simulation and calculation of magnetic field with the antiradial magnetization shows an increase in the precipitant magnetic forces (by normal component of total magnetic force) by 10%-30% in comparison with the analogous in the sizes, known as magnetic system. Non-uniformity of magnetic field of induction on the surface is less to 1.3 and radial magnetic force to 1.7.

STUDY ON AIR PUMPING NOISE IN ROAD CAVITIES

Air-pumping noise generated by a road cavity is studied by an experiment using of an inner drum facility. To simple the problem, the road cavity is modeled as a cylindrical cavity which is processed on the drum surface, and acoustical wave is observed after a tire passed through the cavity. For the difference of the cavity size and the tire velocity, the characteristics of maximum sound pressure and averaging frequency are clarified. The fact that air-pumping noise by the cavity is reduced at the road with the porosity like the drainage asphalt pavement is verified experimentally.

Oxidation of soybean oil during storage of starch‐oil composites

AbstractThe oxidative deterioration of dry starch‐oil composites was investigated by chemical and sensory methods. The composites were stored at 37°C for 63 d, and changes in the hexanal content and odor attributes were monitored. Analysis of the extracted oil showed that the first run through the drum dryer presented higher hexanal concentrations than the subsequent runs. Starch‐oil composites from the first run though the drum dryer showed higher metal concentrations and higher odor ratings during storage time than the subsequent runs. There was a significant correlation between odor attributes and hexanal concentration in the first run. Since both the oxidation and the metal content were higher in the first run and decreased in further runs, we concluded that oxidation might have been induced by the presence of metal in the drum dryer. It is likely that during drum drying, the metal drum and knife surfaces became coated with soy oil, reducing both abrasion and metal contact with the product. Since many applications of the starch‐oil composite technology require drum drying, it will be necessary to take measures to minimize metal contamination of the product, perhaps by discarding the initial portion of product, which contains the most metal.

The effect of molecular weight and the linear velocity of drum surface on the properties of electrospun poly(ethylene terephthalate) nonwovens

In this study, we evaluated the effect of the molecular weight of the polymer on electrospun poly(ethylene terephthalate) (PET) nonwovens, and their mechanical properties as a function of the linear velocity of drum surface. Polymer solutions and electrospun PET nonwovens were characterized by means of viscometer, tensiometer, scanning electron microscope (SEM), wide angle X-ray diffraction measurement (WAXD) and universal testing machine (UTM). By keeping the uniform solution viscosity, regardless of molecular weight differences, electrospun PET nonwovens with similar average diameter could be obtained. In addition, the mechanical properties of the electrospun PET nonwovens were strongly dependent on the linear velocity of drum surface. From the results of the WAXD scan, it was found that the polymer took on a particular molecular orientation when the linear velocity of drum surface was increased. The peaks became more definite and apparent, evolving from an amorphous pattern at 0 m/min to peaks and signifying the presence of crystallinity at 45 m/min.

A Digital Motion Picture Restoration System for Film Archives

A new semi-automatic digital motion picture restoration system for film archives (DIMORF) is introduced, including all stages of restoration, such as scanning, processing and recording. The featured automatism is controlled by occasional operator interactions. All main components are designed and manufactured to meet the special needs of film archive specialists. The film scanner, as well as the laser recorder, reaches a resolution of 6K. The scanner contains a line camera and is able to scan the entire surface of the film, including perforation. The laser recorder, under construction at the time of this proposal, uses a rotating mirror to reflect light onto the film positioned on the inner surface of the recorder drum. The PC-based digital processing unit includes a standalone framework and has a plug-inbased modular interface ready for forthcoming restoration algorithms. Built-in film correction includes stabilization, de-flicker, blotch detection, scratch removal, de-noising, color manipulation, and de-fade effects. Interactive user-support and adaptive algorithms are designed to help semi-automatic operation and thus reduce manpower costs.

An electroelution apparatus for sequential transfer of sodium dodecyl sulfate-proteins into agarose and mass spectrometric identification of Li-Na-dodecyl sulfate-proteins from solubilized agarose.

Separated protein bands are sequentially electrophoresed into low melting agarose plugs distributed in an apparatus of original design along the surface of a plastic drum. The rotation of the drum is synchronized to migration of electrophoretic bands to receive each band individually. Agarose plugs are dissolved enzymatically for transfer into the mass spectrometer. One microL of the agarose solution containing 1 pmol of each of three lithium and natrium salts of dodecyl sulfate (Li-Na-DS)-proteins were applied to matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) without any prepurification. It yields a signal indistinguishable from that obtained in the absence of agarose.

Improvement of Corona Charging System for High Speed Electrophotography

For the purpose of improving the speed of the charging process of electrophotography, a new electrode system was investigated. The system consists of a blade electrode and a metal drum coated with a polymer film. The sharp edge of the blade electrode was retained perpendicularly for the drum surface by opening 2 to 6 mm gap. In order to prevent spark discharge, an 8 MΩ resistor was inserted between the blade and a dc high voltage source, and a glow-like discharge was observed in the space between the blade edge and the surface of the polymer film. As the discharge current obtained by the present electrode system was much higher than that obtained by a single wire corona charger, the charging speed attained by the present system was 7.2 times as fast as the case of the corona charging system.

Optimization of Drum Drying Parameters for Low Amylose Rice (KDML105) Starch and Flour

An attempt was made to study and model the effects of drum drying process variables on the physico–chemical properties of low amylose rice (KDML105) flour and starch. Drum surface temperature, holding time and solid content of the slurry were varied at three levels: 115–135°C, 14–84 s and 20–40%, w/w, respectively. The dependent variables were moisture content (MC), degree of gelatinization (DG), water absorption index (WAI), water solubility index (WSI) and pasting property. High solid content led to a decrease in DG, WAI and initial peak viscosity (IPV) and increase in WSI of dried samples. Longer holding time resulted in increased DG while surface temperature had no significant effect on all characteristics. Predictive correlations were developed using stepwise multiple linear regression to predict MC, DG, WAI, WSI, and IPV of dried products from drum drying variables.

Analysis of the dimensionless torque in cone drum false twisting mechanism

An investigation of the dimensionless torque in the newly developed cone drum twister texturing mechanism is reported. The cone drum twister is one of the outer surface contacting friction-twisting devices in false-twist texturing. In this cone drum twister, a filament yarn passes over the surface of the cone drum that rotates by the passing yarn without a special driving device. This research is composed of the theoretical analysis of the false twisting mechanism and the experimental analysis at room temperature. The equations have been derived which shows interrelationship of the conical angle of cone drum, the wrapping angle, the drag angle, and the yarn helix angle. Theoretical values of dimensionless torque were calculated and were compared with the experimental results. It is shown that, as the conical angle and the projected wrapping angle increased, the dimensionless torque also increased. But the conical angle was reached to 30.75°, the dimensionless torque decreased.

Tire Modeling for Vertical Properties Including Enveloping Properties Using Experimental Modal Parameters

Summary Tire modal parameters reflect the natural properties of the tire. This paper models tire performance using experimental tire modal parameters to calculate the static vertical tire stiffness on both drum and flat road surfaces and the distribution of vertical and shear forces. The model was used to investigate tire enveloping properties. In addition to the radial and tangential displacements, the rotational angular displacement of the contact element is considered. This study examined the obstacle’s effect on tire static vertical properties, the axle load responses under rectangle obstacles with a fixed axle height, and the effects of tire pressure on enveloping properties.

Improvement on the qualities of photosensitive members with cold sealing

Organic photo-conductor (OPC) drum used in a laser printer comprises photosensitive substrates including an anodized layer formed on the surface of an aluminum or aluminum alloy base. Hot sealing method has been dominantly used to seal the pores of anodized aluminum of OPC drum. Cold sealing procedure has been applied to enhance the sealing quality of OPC drum and the result showed that cold sealing method is more effective than hot sealing when the pore size is extremely small. As a result, defects such as spots on the printed images, smudges and cracks on the surface of OPC drum have been removed. Adhesion strength between photosensitive layers and the surface of anodized aluminum has greatly increased with improvement of sealing quality.

Results of surveys at United States pulp and paper mills for the presence of scales and precipitates containing naturally occurring radioactive material (NORM).

Field surveys were carried out at sixteen pulp and paper mills in the United States--seven kraft process, two sulfite process, and seven recycling process mills--for the presence of naturally occurring radioactive material (NORM) in precipitates and scales. NORM was detected at three of the kraft mills, one sulfite mill, and none of the recycling mills. At one of the kraft mills, the NORM was associated with a commercial aluminum sulfate ("alum") slurry used on the paper machines and in intake water treatment. The maximum activity level of this alum scale was 252,000 Bq kg(-1) (6,800 pCi g(-1)) 228Ra. At two kraft mills, NORM was associated with precipitates in the bleach plant. The measured NORM activity in samples of these scales was approximately 44,400 Bq kg(-1) (1,200 pCi g(-1)) 226Ra. Where NORM was detected at a sulfite mill, the NORM deposits were found adhering tightly to the surfaces of brownstock washers. Although samples were not removed for radionuclide analysis, survey readings at the drum surface were 26 nC kg(-1) h(-1) (100 microR h(-1)) with a scintillation counter and 2,200 cpm with a Geiger-Muller counter. At all mills, exposure rate measurements and risk assessment calculations indicated that it would be highly unlikely for any worker's annual exposure to exceed 1 mSv (100 mrem) (the Nuclear Regulatory Commission limit for untrained workers) due to exposure to these materials.

Modeling Electrophotographic Developer Flow with a Viscous Fluid Flow Model

In laser printers, the developing station forms toner images on the photoconductor drum surface. The primary concern for formation of stable toner images is obtaining smooth developer flow. Accordingly, observation of the developer flow at a free surface in an actual developing station has been carried out. For better flow optimization, developer flow details such as local flow velocity vectors and streamlines, not only at the free surface but also in the developer flow, should be clarified. A simulation method for optimizing the flow was examined. In the simulation method, a large calculation domain in the developing station is required. Therefore, viscous fluid analysis is employed to minimize the calculation load. Viscosity should be defined in terms of the developer particle flow. To do this, viscosity measurements were carried out. It was found that the developer flow should be non-Newtonian, whereby viscosity is proportional to the reciprocal of its shear rate. This means that shear stress in the developer flow should optimally be constant. This property was used to simulate the developer particle flow behavior successfully, even in three-dimensional models. Flow details in the developing station, on both large and small scales, could be observed.

Characterisation of the contact patch behaviour of an automobile tyre by physical testing

This paper describes an experimental investigation into the contact patch behaviour of an automobile tyre. The investigation aims to enhance understanding of tyre behaviour in the contact region with reference to the authors' need to validate advanced finite element simulations. Physical tests were carried out with an experimental rolling tyre on flat bed and rolling drum machines, each instrumented with a tri-axial stress transducer. Many plots giving the normal pressure and shear stress distributions under free-rolling and cornering (slip and camber angle) conditions are presented for a high friction surface. A comparison is made between the contact patch behaviour when the tyre is rolled on the horizontal (at 0.18 km/h) and drum (10 to 50 km/h) surfaces. The characteristics of the stress distributions are discussed and related to the actual physical behaviour of the tyre.

Influence of a mixing solvent with tetrahydrofuran and N,N‐dimethylformamide on electrospun poly(vinyl chloride) nonwoven mats

AbstractWe evaluated the effects of the solvent composition with respect to the solution concentration, applied electric field, and tip‐to‐collector distance on the morphology of electrospun poly(vinyl chloride) (PVC) fibers. The solvent volume ratio was strongly correlated with the diameter of the electrospun fibers with respect to the other processing parameters. Electrospun PVC fibers dissolved in tetrahydrofuran (THF) had diameters ranging from 500 nm to 6 μm; those dissolved in N,N‐dimethylformamide (DMF) had an average diameter of 200 nm. The diameters of the electrospun fibers were obtained from narrow to broad distributions with the solvent composition. Also, the diameters of fibers electrospun from a mixed solvent of THF and DMF were less than 1 μm. The mechanical properties of electrospun PVC nonwoven mats depended on the fiber orientation and linear velocity of the drum surface. With increasing linear velocity of the drum surface, electrospun PVC fibers were arranged toward the machine direction, and the dimensions of the spiral path were shorter. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2259–2268, 2002

Conjugate Heat Exchange of Cooled Polymer Films in Jet Pressing of Them Against a Drum

Conditions of heat exchange on the surface of a polymer film cooled on a drum in jet pressing of the film against the drum surface have been studied. The integral methods of thermal calculation of boundary layers have been employed and the contact thermal resistance between the film and the drum has been taken into account in developing a mathematical model. The local thermal characteristics of the films have been obtained. The influence of different parameters on heat‐exchange conditions has been investigated. Comparison of experimental and calculated data has shown their good agreement.

THERMAL CONDITIONS FOR THE PRODUCTION OF MULTILAYER POLYMERIC SHOCK-ABSORBING FILMS

Procedures for the production of multilayer shock-absorbing films specify the heating of one side of each polymeric film by irradiation to the plasticizing temperature, subsequent contact between the films, and their fusion one to the other [1, 2]. Equipment for the production of shock-proof metal based on a dual-layer polymeric film (Fig. 1) operates in the following manner. A single initial film 13 proceeds from unrolling device 12 onto the outer surface of drum 11 using roller 14, is heated to the molding temperature by the drum and infrared heater 10, is shaped under a vacuum in chamber 9, and approaches the point where it comes in contact with the drum and take-up roller 2. A second initial film 6 is directed from unrolling device 7 via guide roller 3 onto take-up roller 2, heated to the plasticizing temperature by guide roller and heater 8, and approaches the point where it comes in contact with the drum and roller 2. Here, both films are compressed and fused. As the drum continues to move, the fused films are cooled, and run together along guide roller 1 from the drum, forming finished product 4, which is wound into a roll by device 5. To avoid rejection, heating of the shock-absorbing film should be carried out in a manner such that the unheated side of the film in contact with the drum (mold) does not fuse to the latter, since in the opposite case, the film will adhere to the drum. The specifics of the film-heating process under consideration is manifested in the rigorous temperature dependence of the thermophysical properties of the polymeric material. In the temperature range of interest to us, the heat conduction and density of the polyethylene vary by 1‐20%, and the heat capacity by 3‐5 times. For calculation of the parameters of the process under consideration, it is therefore impossible to take advantage of familiar analytical solutions of the problem of the heating of a flat plate [3, 4], which are derived on the assumption of constant thermophysical properties of the plate material. The problem of the heating of the film was solved numerically. The heat-conduction equation, and the initial and boundary conditions assume the form

Performance of a double drum dryer for producing pregelatinized maize starches

The response of an industrial scale double drum dryer to variation of steam pressure, drums rotation speed and level (height) of the gelatinization pool between the drums is presented. To our knowledge, this is the first time that the gelatinization pool level is treated as an input variable. The output variables are the product's moisture content, mass flow rate and specific load (equivalent to the product's film thickness). The effect of the drum surface temperature and width of the gap between the drums on the behavior of the output variables is examined. A theoretical analysis is presented for the qualitative assessment of the basic process variables that control the film thickness of the product. The role of the thermal inertia of the drum wall to the response of the dryer is discussed. Changes in the thermal efficiency of the dryer are inferred from overall heat transfer coefficients.