Aeration performance of hydrodynamic flow regulators.

Hydrodynamic flow regulators are used in environmental engineering as a replacement for traditional flow throttling devices. They are extremely efficient, reliable and free from the common disadvantages of traditional devices. Recent research by the authors indicated that the atomization of a liquid by hydrodynamic flow regulators accelerates oxygenation and may be used for improving the quality of wastewater and stormwater. To date, an evaluation of the aeration capacity of a hydrodynamic flow regulator at the pilot scale or in a practical situation has not been presented in the literature. This study presents the experimental results of oxygen absorption tests for conventional and modified cylindrical hydrodynamic flow regulators (patent pending). These devices were tested in a closed-circuit experimental setup at the semi-commercial scale. The aeration efficiency of hydrodynamic flow regulators was assessed by means of the overall standard oxygen transfer coefficient (KLa(20), h⁻¹) and standard oxygen transfer rate (SOTR, gO2/h) for a wide range of tested configurations. The effect of flow rate and discharge mode on the aeration capacity of flow regulators was investigated. The values of KLa(20) for cylindrical hydrodynamic flow regulators obtained in the experiments were between 2.62 and 15.57 h⁻¹ while SOTR values ranged from 53 to 316 gO2/h. The modified discharge mode with two active outlets allowed for an increase in aeration efficiency of up to 15% compared to conventional designs.

Adsorption of methylene blue and Congo red from aqueous solution by activated carbon and carbon nanotubes.

This study was conducted to determine the adsorption removal of dyes by powdered activated carbon (PAC, Norit) and multi-walled carbon nanotubes (MWCNTs, Chinese Academy of Science) from an aqueous solution. Methylene blue (MB) and Congo red (CR) were selected as model compounds. The adsorbents tested have a high surface area (PAC 835 m(2)/g, MWCNTs 358 m(2)/g) and a well-developed porous structure which enabled the effective treatment of dye-contaminated waters and wastewaters. To evaluate the capacity of PAC and MWCNTs to adsorb dyes, a series of batch adsorption experiments was performed. Both adsorbents exhibited a high adsorptive capacity for MB and CR, and equilibrium data fitted well with the Langmuir model, with the maximum adsorption capacity up to 400 mg/g for MB and 500 mg/g for CR. The separation factor, RL, revealed the favorable nature of the adsorption process under experimental conditions. The kinetics of adsorption was studied at various initial dye concentrations and solution temperatures. The pseudo-second-order model was used for determining the adsorption kinetics of MB and CR. The data obtained show that adsorption of both dyes was rapid in the initial stage and followed by slower processing to reach the plateau. The uptake of dyes increased with contact time, irrespective of their initial concentration and solution temperature. However, changes in the solution temperature did not significantly influence dye removal.

[Reconstruction methods in skull base surgery]. / Metody rekonstrukcji w chirurgii podstawy czaszki.

Surgery for extensive skull base lesions inevitably creates multiple tissue defects that require reconstruction. In this paper reconstruction methods applied in 41 skull base surgery procedures are presented. Anterior cranial fossa was involved in 13 operations (4 malignant and 9 non-malignant tumours), middle and posterior cranial fossa in 28 (9 malignant and 19 non-malignant). As a rule all the defects were reconstructed in one stage, immediately after tumour removal. Titanium mesh was the only alloplastic material used to cover bone defects in 7 patients. Otherwise only autografts were used. Postoperatively in all the patients in whom excision and repair of dura was necessary, continuous lumbar drainage of cerebrospinal fluid was maintained for 4-6 days. In anterior cranial fossa area large pediculated, vascularized periosteal flap allowed for reliable separation of upper airways from intracranial cavity. Titanium mesh was used to cover orbital wall defects. In the area of middle cranial fossa and temporal bone the most important aspects of reconstruction were watertight closure of the dura, separation of the surgical cavity from nasopharynx with rotated temporalis muscle, and facial nerve reconstruction (the nerve was reconstructed in 7 cases). Additionally in 1 patient hypoglossal nerve was sutured end-to-end. In 2 patients the invaded segment of internal carotid artery was excised and replaced with prosthesis. In 13 patients the surgical procedure was performed in an area that was previously operated upon and/or irradiated. Delayed healing was seen in 6 cases, but none required additional procedures and the wounds were completely healed with local treatment. Reconstruction methods presented in this paper are relatively simple and do not necessitate modern materials. Even in extensive procedures proper wound healing and satisfactory cosmetic result were obtained.

[Continuation of care after partial surgery for laryngeal cancer]. / Opieka bez Konca po operacjach czesciowych z powodu raka krtani.

Removing of focus cancer in partial laryngectomy is going with the risk of local recurrence and the appearances of the next atypia cancer focus in the respiratory tract. Using of the new endoscopic methods can allow for total control in out patient department.

[Functional reconstruction after partial laryngectomy for laryngeal cancer]. / Czynnosciowa rekonstrukcja po operacjach czesciowych raka krtani.

Partial laryngectomy of larynx cancer are limited by difficulties in reconstruction at the same time the anatomical way of the upper respiratory tract with secure maintenances defence and phonation functions. Authors present their own way of reconstructive surgery which can allow to make good condition for the comfortable life.

[Complications after partial surgery for laryngeal cancer]. / Powiklania po operacjach czesciowych z powodu raka krtani.

We present 45 patients with laryngeal carcinoma after partial various type laryngectomy results in 1989-1995. Frequency occurrence complication was dependent on localisation and expations. The most often complications after operation are; dyspnea which needs tracheotomy done and nor radicality in histopathological example which press the surgeon to make total laryngectomy. Authors present the types of conservative and surgical treatment of anatomical and functional reconstruction of larynx.

[Multifocus or recurrent carcinoma adenoides cysticum]. / Wieloogniskowosc czy wznowa carcinoma adenoides cysticum.

Authors present the case of carcinoma adenoides cysticum, which was located in small salivary glands of palatum. After surgical treatment and radiotherapy during 3 years observation of the patient two new ca adenoides cysticum focus were noticed. It can give evidence of cancer multifocus of cancer recurrents.

[Multi-stage anatomical-functional reconstruction in surgical treatment of cancer of the mouth floor and tongue]. / Wieloetapowa anatomiczno-czynnosciowa rekonstrukcja w leczeniu chirurgicznym raka dna jamy ustnej i jezyka.

Authors present multistage surgical treatment of cancer disease with its radical dissection and anatomical reconstruction of risected tissue diminution and consecutive functional reconstruction of organs and tissue elements in later stage.

[Monitoring of a patient with nasal papilloma]. / Monitorowanie pacjenta z brodawczakiem nosa.

Papilloma of the nose requires radical, surgical procedure, because may occur of the recurrences and metaplasia. The lateral rhinotomy is the most recommended technique as good total and radical for excision of the tumor. We present 25 cases of papilloma treated in the Otolaryngological Department in Warsaw. The new methods of the pre-, intra- and post-operative evaluation using endoscopy, especially microscope endoscopy has been used. Endoscopy is also very valid methods for post-operative monitoring follow-up.

Synthesis of microspheres of triuranium octaoxide by simultaneous water and nitrate extraction from ascorbate-uranyl sols.

A new method for synthesis of uranium oxide microspheres (diameter <100 µm) has been developed. It is a variant of our patented Complex Sol-Gel Process, which has been used to synthesize high-quality powders of a wide variety of complex oxides. Starting uranyl-nitrate-ascorbate sols were prepared by addition of ascorbic acid to uranyl nitrate hexahydrate solution and alkalizing by aqueous ammonium hydroxide and then emulsified in 2-ethylhexanol-1 containing 1v/o SPAN-80. Drops of emulsion were firstly gelled by extraction of water by the solvent. Destruction of the microspheres during thermal treatment, owing to highly reactive components in the gels, requires modification of the gelation step by Double Extraction Process-simultaneously extraction of water and nitrates using Primene JMT, which completely eliminates these problem. Final step was calcination in air of obtained microspheres of gels to triuranium octaoxide.