Cover Image,Volume 69, Issue 3

The cover image is based on the Mini‐Review Well‐defined, environment‐friendly synthesis of polypeptides based on phosgene‐free transformation of amino acids into urethane derivatives and their applications by Takeshi Endo et al., https://doi.org/10.1002/pi.5952 . Cover image © Takeshi Endo Images.

     

Mechanical properties of polyethylene mixtures crystallized under high pressure

The mechanical properties of a medium molecular weight polyethylene (MMW‐PE) and an ultrahigh molecular weight PE (UHMW‐PE) binary mixture with different weight fractions crystallized from the melt at 0.1 and 450 MPa were studied. The tensile modulus, yield stress, and strain were obtained as a function of the weight fractions in the PE mixtures at 25 and 85°C. The tensile modulus in the sample crystallized at 0.1 MPa decreased from 1.5 GPa of pure MMW‐PE to about 0.4 GPa of pure UHMW‐PE with the UHMW‐PE content but it did not decrease with the UHMW‐PE in the sample crystallized at 450 MPa in testing at 25°C. A decreasing rate of the storage modulus E′ of UHMW‐PE in a dynamic measurement for the sample crystallized at 0.1 MPa with the temperature is larger than that of the sample crystallized at 450 MPa. These experimental facts are interpreted in relation to the molecular motion and crystallinity of the sample. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1962–1968, 2003     

EFFECT OF DEVELOPER PROPERTIES ON PRINT QUALITY

We investigated the dependence of the toner charge-to-mass ratio (q/m) in a two-component electrophotographic developer on the shaking time, toner concentration (T/C), carrier sizes, and the carrier core and the coating materials, as well as the resulting print qualities in terms of print density, background density, tone reproduction, resolution, and dot gain. Four different sizes of spherical ferrite carriers, four different carrier coating materials, and an irregular iron carrier were used with two types of toner: 14 um red toner (NP-4080) and 8 um cyan toner (CLC-500). The q/m measurement by the blow-off method showed that the red toner charge was positive while the cyan toner charge was negative with these carriers. The toner q/m values, which depended on the shaking time and decreased with the increasing T/C were much more affected by the larger carrier and the smaller toner. The carriers which yielded charges in the proper range produced better print qualities than did the other carriers that yielded a toner q/m     

A method of identifying latent human errors in work systems

Work system improvements are implemented in various manufacturing processes to prevent problems caused by human errors. However, they are almost always applied to problems which have already occurred. This paper examines a method of identifying latent human errors existing within the work systems beforehand. A procedure for applying failure mode and effect analysis to this identification problem was defined based on over 1000 empirical errors: a work system decomposition criterion and fundamental error modes for listing latent human errors, and then applied to three practical manufacturing processes in order to evaluate its effectiveness.     

Correlation between serum levels of alanine aminotransferase and ferritin in male blood donors with antibody to hepatitis C virus

Chronic hepatitis C has been demonstrated to be associated with hepatic iron overload, and the hypothesis that the disease activity of hepatitis C is associated with iron cytotoxicity was tested in male volunteer blood donors. Sera with either antibody to hepatitis C virus or hepatitis B surface antigen were selected for determination of ferritin concentration and alanine aminotransferase activity. A correlation between serum ferritin concentration (Y; microgram/l) and alanine aminotransferase activity (X; IU/l) was found in donors with antibody to hepatitis C (log Y = 0.65 x log X + 0.98, r = 0.53, and P < 0.01). The correlation was lower in donors with hepatitis B surface antigen (r = 0.37; P < 0.01). Hepatitis C virus infection probably induces time-dependent iron accumulation associated with the progression of disease activity, while hepatitis B virus infection results in a variety of iron loads with different clinical features. The high disease activity related to hyperferritinemia suggests the presence of iron-induced liver damage in donors with hepatitis C.     

Efficiency of repeated batch penicillin fermentation using two fermentors. Computer simulation and optimisation

Repeated batch operation using two fermentors (RBTF) to penicillin fermentation was demonstrated by computer simulation to improve productivity. Three operation modes were compared: chemostat, repeated batch operation using a single fermentor (RBSF) and RBTF; in each case account was made of the lag period before growth. The simulated fermentor performances were assessed on the basis of the penicillin productivity and concentration; the simulation was based on published batch fermentation data. It was shown that RBTF was superior to RBSF and chemostat. The advantage of RBTF increased as the lag period became greater.     

Characterization and electrochemical properties of CF4 plasma-treated boron-doped diamond surfaces

The effect of CF₄ plasma etching on diamond surfaces, with respect to treatment time, was investigated using scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electrochemical measurements. SEM observations and Raman spectra indicated an increase in surface roughening on a scale of 10–20 nm, and an increase in crystal defect density was apparent with treatment time in the range of 10 s to 30 min. In contrast, alteration of the diamond surface terminations from oxygen to fluorine was found to be rather rapid, with saturation of the F/C atomic ratio estimated from XPS analysis after treatment durations of 1 min and more. The redox kinetics of Fe(CN)₆^3−/4− was also found to be significantly modified after 10 s of CF₄ plasma treatment. This behavior shows that C–F terminations predominantly affect the redox kinetics compared to the effect on the surface roughness and crystal defects. The double-layer capacitance (C_dl) of the electrolyte/CF₄ plasma-treated boron-doped diamond interface was found to show a minimum value at 1 min of treatment. These results indicate that a short-duration CF₄ plasma treatment is effective for the fabrication of fluorine-terminated diamond surfaces without undesirable surface damage.     

A Nonvolatile Organic Memory Device Using ITO Surfaces Modified by Ag‐Nanodots

We report on a single‐layer organic memory device made of poly(N‐vinylcarbazole) embedded between an Al electrode and ITO modified with Ag nanodots (Ag‐NDs). Devices exhibit high ON/OFF switching ratios of 10⁴. This level of performance could be achieved by modifying the ITO electrodes with some Ag‐NDs that act as trapping sites, reducing the current in the OFF state. Temperature dependence of the electrical characteristics suggest that the current of the low‐resistance state can be attributed to Schottky charge tunnelling through low‐resistance pathways of Al particles in the polymer layer and that the high‐resistance state can be controlled by charge trapping by the Al particles and Ag‐NDs.     

Real-time measurement of pointing action by using DSP

This paper presents an approach of measuring in real-time the vector of finger that is pointing to an object. DSP is used in the operation processing unit in order to do the real-time processing. The steps include the extraction of flesh-colored regions from an image, the labeling of the flesh-colored regions, and the detection of two characteristic positions on the finger so that the direction that the finger is pointing at will be calculated. The entire process takes about 29 msec, which makes it possible to have the frame rate of 34 fps. With this frame rate, this measurement approach is considered real-time and promising to be merged into other application systems. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Electromagnetic shielding of HF lamps using wire structures:simulation and measurement

High-frequency (HF) operated lamps, such as HF fluorescent lamps, have several advantages over conventional ones but they contaminate the environment with their EM field emissions. The shielding of the electromagnetic emission should be realized without much effect on the emission of the light. Enclosing the lamps in a housing made of widely spaced thin wires could be an appropriate way to shield the electromagnetic field. The paper studies the effectiveness of some wire structures for shielding the electromagnetic emission from HF fluorescent lamps. An analytical study, method of moments (MoM), and measurements have been carried out to evaluate the strength of the near-field and the shielding effectiveness of the structures