Influence of Traditional Wood Surface Modification Methods on Changes in Aesthetic and Resistance Properties

For ages, furniture makers have been using various methods to accelerate the natural process of wood aging, in order to achieve a more sophisticated colour and to provide a uniform appearance for furniture parts replaced during restoration. Nowadays, wood aging is popular due to its aesthetic value associated with naturally aged wood, which can be enjoyed in conjunction with favourable mechanical properties of contemporary wood. Methods of wood surface modification used in wood aging can be divided into mechanical ones, consisting in changing the structure of wooden surfaces (eg. sanding, brushing, paint rubbing or structuring with chisel or other tools) and chemical ones, involving the use of chemical substances to change the colour of wood (eg. greying; application of lye, paint or wood stain; and ammonia fuming). The purpose of our study was to determine the influence of traditional wood modification techniques used in furniture-making − such as: structuring, whitewashing, rubbing, greying, dyeing with potassium permanganate solution and ammonia fuming − on the aesthetic and resistance properties of wooden surfaces (colour, gloss, roughness, abrasion resistance and resistance to scratches). Tests were performed on wood species most frequently used in Poland to produce artificially weathered wood: Scots pine (Pinus sylvestris L.) and common oak (Quercus Sp).

An Improved Ion Chromatographic Method for Fast and Sensitive Determination of Hexavalent Chromium and Total Chromium Using Conductivity Detection

Chromium exists in its two stable oxidation states including trivalent chromium (Cr (III)) and hexavalent chromium (Cr (VI)) in natural waters. Chromium is an essential micronutrient in the trivalent form; however, the hexavalent form of chromium is considered to be a carcinogen. It is important to determine the chromium content along with speciation. There are a number of methods available for chromium determination. Speciation of chromium is essential to know the exact composition of chromium. Ion exchange chromatography is one of the techniques used to determine Cr (VI). The proposed method can be used to perform the speciation of Cr (III) and Cr (VI). It is a two-step process: first Cr (VI) is determined, followed by total chromium determination by treating the sample with potassium permanganate solution to oxidize the Cr (III) present in the sample to Cr (VI) and determining it as Cr (VI). Conductivity detector is used for the detection. Addition of potassium permanganate solution to the ground water samples for oxidizing the Cr (III) to Cr (VI) is the newly adopted sample preparation technique. The effect of potassium permanganate oxidation is studied in detail in the proposed method. This method can be used for chromium speciation in river water and ground water samples.

Effect of Oxidizing Decontamination Process on Corrosion Property of 304L Stainless Steel

Corrosion behaviors of 304L stainless steel (SS) and 304L SS with oxides film (preoxidation 304L SS) in 1 g/L potassium permanganate solution of various pH values were investigated by using mass loss, electrochemical measurement and scanning electron microscope (SEM) observation. The results showed that mass loss of 304L SS increases with the increase of sodium hydroxide or nitric acid concentration in 1 g/L potassium permanganate solution. The polarization curves of 304L SS in potassium permanganate solution show that passive zones are destroyed more easily in acid potassium permanganate solution than alkaline potassium permanganate solution. The corrosion ability of acid potassium permanganate (NP) decontamination solution used for 304L SS is more aggressive than alkaline potassium permanganate (AP) solution. The oxide film on the surface of preoxidation 304L SS can be removed completely in two oxidation reduction decontamination cycles, oxidizing solution of which comprised 0.4g/L sodium hydroxide and 1g/L potassium permanganate. The 304L SS and preoxidation 304L SS performed alkaline oxidation reduction decontamination of 3 cycles were reoxidation. The micromorphology of reoxidation specimens was similar to preoxidation 304L SS. Therefore the chemical decontamination of alkaline oxidizing and acid reducing steps had no negative effect on corrosion of 304L SS and reoxidation of 304L SS carried out decontamination.

Some Observations on Thin Layer Chromatography Technique

The present study is to report the various problems faced during TLC methodology. Although used regularly some technical aspects must be kept in mind to get better and uniform results. During our experiments with TLC methods we came across some problems and here these aspects of TLC methodology are being highlighted. It is suggested that the solvent use as mobile phase should also be used for extraction of any particular phytochemical. TLC plates should be 3 to 4 mm thick, to be dried for at least 72 hrs. It is also suggested that potassium permanganate solution gives better clarity in visualizing the spots