M. Atar, H. Keskin, S. Korkut and D.S. Korkut
The purpose of this paper is to investigate how impregnation with boron compounds affects the surface hardness of varnished wood materials.
Abstract
Purpose
The purpose of this paper is to investigate how impregnation with boron compounds affects the surface hardness of varnished wood materials.
Design/methodology/approach
Test samples were prepared from Scotch pine, Oriental spruce, and Uludag fir, which met the requirements of ASTM D 358.These samples were impregnated with boric acid (Ba) and borax (Bx) using a vacuum technique, according to ASTM D 1413 guidelines. After impregnation, surfaces were coated with cellulosic, synthetic, polyurethane, water‐based, acrylic, and acid‐hardening varnishes in accordance with ASTM D 3023 guidelines. Surface hardnesses of specimens after the varnishing process were determined, in accordance with ASTM D 4366 guidelines.
Findings
Surface hardness was greatest for samples of spruce treated with Ba and polyurethane varnish, and lowest for samples of Scotch pine treated with Bx and synthetic varnish. With regard to wood type, impregnation material, and varnish type, surface hardness was greatest for Oriental spruce impregnated with Ba and polyurethane varnish and lowest for Scotch pine impregnated with Ba and synthetic varnish. Thus, impregnation with boron compounds increased the surface hardness of the varnished wood.
Research limitations/implications
A protective coating (such as varnish) has limited resistance to external effects and the lifetime of the coating will be determined by the type and severity of conditions to which it is exposed.
Practical implications
Types of varnishes, wood materials, and impregnation chemicals affect surface hardness and can influence the usefulness of wood materials, where surface hardness values are important.
Originality/value
The study results reported in the paper help address the lack of research in this field and should be informative, in particular, for manufacturers and consumers in the furniture and decoration sector.
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Hakan Keskin, Musa Atar, Süleyman Korkut and Derya Sevim Korkut
The purpose of this paper is to determine the effect of Imersol Aqua impregnation of Scotch pine, Oriental spruce, and Uludağ fir on the surface adhesion strength of various types…
Abstract
Purpose
The purpose of this paper is to determine the effect of Imersol Aqua impregnation of Scotch pine, Oriental spruce, and Uludağ fir on the surface adhesion strength of various types of varnishes. The finding obtained would benefit the manufacturers of building materials and furniture, where the surface adhesion strength of water‐based varnishes is a concern.
Design/methodology/approach
For this purpose, test samples were prepared from Scotch pine, Oriental spruce, and Uludağ fir woods that met the requirements of ASTM D 358. The samples were impregnated with Imersol Aqua using short‐, medium‐, and long‐term immersion techniques according to ASTM D 1413 and the manufacturer's instructions. After impregnation, surfaces were coated with synthetic, acrylic, polyurethane, and water‐based varnishes in accordance with ASTM D 3023 standards. After the varnishing process, the adhesion strength of the samples was determined in accordance with ASTM D 4541.
Findings
It was also found that among the wood samples, the adhesion strength was highest in Scotch pine and lowest in Uludağ fir. The synthetic varnish produced the highest adhesion strength, whereas polyurethane and acrylic varnishes had the lowest adhesion strength. The adhesion strength was highest after medium‐term immersion and lowest after long‐term dipping. The highest adhesion strength (4.299 MPa) was produced by a combination of Scotch pine, medium‐duration immersion, and the use of a wood‐based varnish. The lowest adhesion strength (2.090 MPa) resulted from the combination of Uludağ fir, long‐term immersion, and a water‐based varnish.
Research limitations/implications
Impregnating woods using materials with appropriate water repellent, biotic, and abiotic effects before the application of varnishes and paints is important for long‐term protection against photochemical degradation, dimensional changes, biological factors, and fire.
Practical implications
The effect of a varnish on surface adhesion strength can determine the usefulness of the varnish.
Originality/value
Improving surface adhesion of some varnishes via medium‐term impregnation with Imersol Aqua impregnation should be used on Scotch pine, Oriental spruce, and Uludağ fir woods which could be used in the manufacturing of building materials and furniture, where the surface adhesion strength of water‐based varnishes is a concern.
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Shaikh Asad Ali Dilawary, Amir Motallebzadeh, Muhammad Afzal, Erdem Atar and Huseyin Cimenoglu
The purpose of the study is to examine the sliding wear performance of plasma transfer arc (PTA) deposited and laser surface melted (LSM) Mo modified Stellite 12 hardfacings under…
Abstract
Purpose
The purpose of the study is to examine the sliding wear performance of plasma transfer arc (PTA) deposited and laser surface melted (LSM) Mo modified Stellite 12 hardfacings under high contact stresses (i.e. >20 GPa).
Design/methodology/approach
For this purpose, after structural characterization, sliding wear tests have been conducted using sphero-conical diamond indenter as the counterface with different normal loads. The wear tracks formed on the hardfacings were examined by atomic force microscopy and scanning electron microscopy.
Findings
Both hardfacings showed severe wear (at high contact stress levels ranging from 24 to 41 GPa), which progressed by plastic deformation, although the wear resistance of LSMed hardfacings was better than the PTA hardfacings by a factor of two due to its near surface microstructure characterized as carbide-rich zone.
Originality/value
Sliding wear characterization of a promising 10 Wt.% Mo modified version of commercial Stellite 12 hardfacings (as reported previously by authors) was done in as PTA and LSMed states using nanomechanical test system. To the best of authors’ knowledge, no report is available in the open literature on such hardfacings under these testing conditions.
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THE twentieth Salon International de l'Aéronautique was held from June 26 to July 5, the stands being housed in a new permanent building at the south‐eastern extremity of the…
Abstract
THE twentieth Salon International de l'Aéronautique was held from June 26 to July 5, the stands being housed in a new permanent building at the south‐eastern extremity of the airport of le Bourget with the outside static aircraft part and runways nearby. Apart from being much more convenient for exhibitors and public, the new arrangement seems to coincide with a resurgence of confidence in the French aircraft industry. A number of interesting new prototypes were shown, and there are now more aircraft for which production orders have been placed, although usually only in moderate quantities.
The purpose of this paper is to determine the impacts of impregnation with Imersol Aqua to red colour tone (RCT) of some softwood materials and varnishes.
Abstract
Purpose
The purpose of this paper is to determine the impacts of impregnation with Imersol Aqua to red colour tone (RCT) of some softwood materials and varnishes.
Design/methodology/approach
For this purpose, test samples prepared from Scots pine (Pinus sylvestris Lipsky), Oriental spruce (Picea orientalis Link) and Uludağ fir (Abies Bornmülleriana Mattf.), which met the requirements of ASTM D 358, were impregnated with Imersol Aqua by short‐term, medium‐term and long‐term immersion techniques in accordance with ASTM D 1413 and producer's definition. After impregnation, surfaces were coated by synthetic, acrylic, water‐based and polyurathane varnishes in accordance with ASTM D 3023 standards. RCT values of samples after varnishing process were determined in accordance with ASTM D 2244.
Findings
It was found that RCT was the highest in Scots pine, long‐term dipping and synthetic varnish, and the lowest in Uludağ fir, short‐term dipping and water‐borne varnish. Considering the interaction of wood type, period of impregnation and type of varnish, RCT was the highest in pine, short term of dipping and acrylic varnish and the lowest in Oriental spruce, short term of dipping and synthetic varnish. So, impregnation process, impregnation period and varnishes applied during tests showed increasing impact for RCT value of Scots pine, Oriental spruce and Uludağ fir woods. This result must be taken into care in manufacture of wooden furniture and construction elements where RCT is important.
Research limitations/implications
The endurance of the protective coating (such as varnish) to external effects is limited and the lifetime of the coating is determined by the type and the severity of the effects to which it is exposed.
Practical implications
The impact of varnish type, wood material type and impregnation chemical on RCT can determine the usefulness of the massive wood materials where RCT values are important.
Originality/value
It is conjectured that especially for the manufacturers and consumers in the furniture, construction and decoration sector, the data obtained in this study will contribute to the making up of the deficiencies in the understanding of the subject.
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THE General Dynamics)'Grumman F‐111 fighter is noteworthy on many counts: first, and most important in the context of coverage of variable sweep types in this issue, the F‐111 is…
Abstract
THE General Dynamics)'Grumman F‐111 fighter is noteworthy on many counts: first, and most important in the context of coverage of variable sweep types in this issue, the F‐111 is the world's first variable sweep air‐craft to be designed and built for operational service. Second, the F‐111 represents the first successful attempt by the United States to design and build a multi‐mission aircraft suitable for service with both the United States Navy and the United States Air Force—obviously the F‐111 is not the first aircraft to become operational with more than one of the United States services (the McDonnell Phantom is currently in service with the U.S.A.F., the U.S. Navy and the U.S. Marines)—but it is the first to be designed from the initial concept to satisfy U.S.A.F. and U.S. Navy mission requirements. Thirdly, the existence of the F‐111 programme was directly responsible for the cancellation of the TSR‐2 programme because even though Britain's Government cur‐rently appear to be seeking an alternative replace‐ment for the cancelled TSR‐2 (in the form of an uprated Hawker Siddeley Buccaneer—designated the Buccaneer 2 Star—or an improved Dassault Mirage IV with two afterburning Rolls‐Royce Speys instead of the S.N.E.C.M.A. Atar turbo‐jets), it is doubtful if the TSR‐2 would ever have been cancelled had not the American Government offered Britain the opportunity of pur‐chasing the high‐performance multi‐mission F‐111 as a lower cost substitute. If the R.A.F. does re‐equip with the F‐111 instead of the TSR‐2 then in terms of performance, i.e. range, speed, weapons load, ability to survive at low level, ability to navigate to target in all weathers (day and night), ability to operate from short rudimentary airstrips and ferry range, the F‐111 should, with only mild reservations, fulfil all the mission profiles planned for the TSR‐2, and will offer attractive bonuses in addition. On the other hand, unless something approaching a complete redesign and rebuild of the Buccaneer or Mirage IV is carried out, neither aircraft can approach the performance of the TSR‐2.
WHEN talking about airbreathing engines it is now generally understood that they are either turbine engines when the maximum flight Mach number is subsonic or moderately…
Abstract
WHEN talking about airbreathing engines it is now generally understood that they are either turbine engines when the maximum flight Mach number is subsonic or moderately supersonic, or ramjets when the Mach number is definitely high. When trying to meet the propulsion requirements from take‐off to a high enough speed the joint use of both engine types has to be considered. In such case most people would think of the ramjet as taking over the propulsion task from the turbine engine when reaching a certain value of the flight Mach number, or more precisely of the air stagnation temperature, above which the turbine engine is no longer able to operate. The most elementary view is that of presenting it as a limitation in the engine structure, with improvements calling for the use of better materials. Bringing thermo‐dynamics into the picture shows that increased air stagnation temperature results in a deterioration in the cycle efficiency of the turbine engine proper and this may result in the specific fuel consumption of the turbojet becoming higher than that of the ramjet. Such a performance limitation can be shifted to higher Mach numbers while using increased turbine intake temperatures. The consideration of the aerodynamics of the internal flow brings out another type of limitation due to the difficulty of keeping the operating line of the turbojet over the flight profile far enough from the surge limit though within the range of good compresser efficiency. Variable geometry in the compressor and turbine stators may produce some improvement in this respect.
The paper discusses current trends and future developments in the study of people-urban environment relations, with an emphasis on the concept of diversity within the Gulf cities…
Abstract
The paper discusses current trends and future developments in the study of people-urban environment relations, with an emphasis on the concept of diversity within the Gulf cities. This is explored in relation to: theoretical approaches, urban public spaces, people's lifestyles, social groups and inclusive urban environments. Contemporary Gulf cities are providing unique examples for research on urban diversity. Its demographic structure is distinctive for a minimum of 50% expatriates in overall population. Gulf cities are obliged to cope with such a compelling fact. The challenge is to move away from indifference and bring about better acceptance of others. On the relationship; city spaces and culture, the paper argues that traditional markets must be envisioned as spaces for cultural expressions. Traditional markets are a rich display of products and talents and a great opportunity to share and meet with people from same culture and others. Using comparative analysis approach juxtapositioning the selected cases, the paper confronts questions like what does Gulf urban diversity mean in the present. In addition, is diversity in urban spaces only a challenge to be dealt with or is there also economic potential that can be taken advantage of? How do we ensure that Gulf cities are indeed spaces of tolerance? How to give visibility to the spaces of marginalized groups, as these spaces are often ignored or worse, eliminated? How to preserve or regain spaces in the city for the expression of traditional cultures of those migrating from other regions or countries? The paper explores the socioeconomic and cultural mechanisms that can encourage inclusive pluralism in the Gulf cities' open spaces.
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ONLY six weeks after its initial run the Olympus 593 B engine for the Concorde attained 33,000 lb. thrust without reheat, e highest figure achieved for a European turbo‐t. This…
Abstract
ONLY six weeks after its initial run the Olympus 593 B engine for the Concorde attained 33,000 lb. thrust without reheat, e highest figure achieved for a European turbo‐t. This news came just after the third anniversary the Anglo‐French Treaty of Collaboration gned in November 1962. For Bristol Siddeley d S.N.E.C.M.A., the British and French partners the Concorde engine programme, the three ears have been a period of considerable activity. When Concorde was first projected, the engine oposed was a developed version of the military lympus 320 for the TSR‐2, modified for civil peration. Like the earlier series of military lympus engines, the 320 was a two‐spool engine, ach compressor driven by a separate turbine, ith a cannular combustion chamber.
This study aims at presenting one of the most important problems of aeroplane design, Static Longitudinal Stability, in a possibly complete but easy way.