Numerical and experimental investigation of melting of ice involving natural convection

Two‐dimensional transient melting of ice in a rectangular enclosure was numerically and experimentally investigated. Natural convection in the liquid phase due to the temperature dependency of water density was considered in the numerical model. The implicit finite difference method with fixed staggered grid approach was utilized. The SIMPLER algorithm was followed for the solution of pressure and velocity fields in the liquid phase. The prediction of the model was found to be satisfactory through preliminary experimentation. Copyright © 2002 John Wiley & Sons, Ltd.     

Controlled Distribution of Solid Catalysts into Two Immiscible Liquid Phases – Synthesis and Catalytic Applications

Photometathesis of C₃H₆ proceeded on the sprayed MoO₃ catalyst under UV irradiation with wavelength <290 nm. The photoactivity on the spray catalyst was 20-fold higher than that on the commercial MoO₃. The X-ray diffraction (XRD) results showed the anisotropic growth of the crystal in the spray catalyst. The edge-rich structure was formed in the bulk molybdenum oxide by spray reaction technique.     

Infantile spasms as the initial symptom of biotinidase deficiency

Two patients with biotinidase deficiency had diagnoses of infantile spasms made at 1 month of age. Biotinidase deficiency may be seen early in the neonatal period without the characteristic findings such as alopecia and seborrheic dermatitis. This diagnosis should be considered in patients with infantile spasms.     

Pregnancy after transfer of embryos which were generated from in-vitro matured oocytes

In-vitro maturation of human oocytes is an important technique in assisted reproduction due to its potential for reducing the use of fertility drugs. We offered this technique as an alternative to cancelling the cycle to a patient who was at risk of ovarian hyperstimulation syndrome (OHSS) after treatment with gonadotrophin-releasing hormone analogue (GnRHa) and human menopausal gonadotrophin (HMG). The patient had 40 visible antral follicles with a maximum diameter of 13 mm and an oestradiol concentration of 14,000 pmol/l on cycle day 12. Immature oocytes were aspirated transvaginally under ultrasound guidance. Ten cumulus-enclosed oocytes were harvested and nine of them completed nuclear maturation to metaphase II after 48 h in culture. By 18 h after an intracytoplasmic sperm injection (ICSI) procedure, seven of these metaphase II stage oocytes displayed two distinct pronuclei and two polar bodies. All fertilized oocytes but one underwent cleaveage; four of these were transferred 2 days later. Endometrial priming was initiated with 8 mg oestradiol valerate daily from the day of oocyte retrieval and 50 mg progesterone was injected i.m. daily starting 2 days after that. A single intrauterine sac was seen containing one fetus with positive fetal heart beat on ultrasound at 7 weeks of gestation. Unfortunately, the pregnancy ended at 24 weeks shortly after premature rupture of membranes; a live healthy-looking girl was delivered who died 18 days later.     

Effects of composition, texture and diagenesis on porosity, permeability and oil recovery in a sandstone reservoir

Relationship among depositional texture, composition, diagenesis, porosity, permeability, initial water saturations and residual oil saturations have been investigated in a set of sandstone samples from a North American oil reservor. Pointcount, compositional and textural data obtained from thin sections were used.Grain size, sorting and mineralogy are closely interrelated. As grain size increases, sorting decreases and the proportion of readily soluble detrial grains increases.The type and extent of diagenetic alteration is related to grain size. Silica cement as overgrowths is more common in finer-grained sandstones with abundant monocrystalline quartz, whereas carbonate cement is more common in coarsergrained sandstones. Carbonate dissolution is extensive in some intervals in the reservoir.Sandstone samples were subdivided into tow subgroups in which relationshiops among grain size, porosity and permeability are significantly different: Sandstones with less than 13% porosity are strongly influenced by carbonate cement which controls porosity and permeability, independently of variations of grain size and sorting. Sandstones having porosity greater than 13% have undergone extensive carbonate dissolution, and coarse-grained sandstones have more secondary porosity than the finer-grained due to dissolution of unstable constituents. Both porosity and permeability are positively correlated with grain size in these samples.Initial (connate) water saturation increases with grain size because of the strong correlation between increasing grain size and polycrystalline grains which have intra-grain microporosity. Increasing heterogeneity with increasing grain size is thought to contribute to higher residual oil saturations in coarser-grained, more poorly sorted sandstones. A decrease in oil recovery efficiency with increasing grain size and permeability may be predicted for other sandstone reservoir rocks deposited in similar types of environments.     

A note on histamine levels in Turkish style fermented sausages

The histamine contents of Turkish style fermented sausages were determined on 46 samples of five different brands obtained from retail stores in Van in Turkey. Histamine was found in all samples in the range 19.64-87.47 mg/kg (mean 32.13 mg/kg). Histamine levels in the brands differed significantly (P<0.01). The results suggest that the histamine levels in the sausages were not hazardous in terms of public health although they may be a potential risk to sensitive individuals.     

A novel approach to degree-hour calculation: Indoor and outdoor reference temperature based degree-hour calculation

This paper presents a novel approach to temperature probability density distribution and function. Probability density functions and frequency are successfully used in wind speed and solar energy analyses in literature. This study applies these data to temperature data analysis. The present model is developed using the indoor and outdoor temperature as a parameter. Outdoor temperature distribution is crucial for the calculation of monthly and total degree-hour. In this paper, using past weather data, the outdoor temperature probability density functions are modeled for four cities in different regions in Turkey via a new computer program. The main advantage of this approach is to allow us to determine heating and cooling loads with respect to different indoor and outdoor temperatures.     

The fabrication of exfoliated graphite sheet-based air cathodes and gel electrolyte for metal-air batteries

In this paper, we demonstrate that activated carbon (AC) and manganese dioxide (MnO₂) coated exfoliated graphite sheets are a promising cathode for metal-air batteries. A simple and effective method is developed to exfoliate the graphite sheets and to load a catalyst onto their surfaces. Several low-cost, environmentally friendly air cathodes are fabricated, and their performances are tested by constructing Al-air b`atteries whose electrolyte 6 M NaOH, including ZnO inhibitor, is gelled by adding a cost-effective water retainer. The experimental results show that this new Al-air battery has a good discharge performance. In particular one of the new cathodes containing 50 wt% AC and 50 wt% MnO₂ produces a capacity of 311 mAh/g at a constant current discharge of 1.56 mA. Finally, future research directions are discussed for the further usage of the fabricated cathodes.