In this study, effects of adhesive and additive's type and ratio on burning characteristics of particleboard (PB) added glass wool (GW) and rock wool (RW) were researched. PB's furnish was derived from 50% Crimean pine, 30% Eastern Black Sea oak, 15% quaking aspen, and 5% residues of wood machining, and moisture content of furnish was 1.5 to 3%. Seventy PBs with 0.64 g/cm3 density, urea formaldehyde (UF)/melamine formaldehyde (MF) fixed amount, 14 mm thickness, 45x45 cm2 dimensions and 10%, 15%, 20% SW/GW additives were produced. The 150 oC pressing temperature with 25 kg/cm2 compression pressure was constant. Burning tests for determination of ignition time, flaming combustion temperature, flaming combustion duration, smoldering combustion duration, and mass loss during burning were made according to DIN4102 standards. According to the results of the tests, adhesive type did not affect ignition time and mass loss. While flaming combustion temperature of PB with UF was 19% higher, flaming combustion duration and smoldering combustion duration was 32% and 29% lower than those of PB with MF, respectively. While ignition time of PB with GW was 50% higher than that of PB with RW, changes in burning properties were similar for both PBs. An increase in the content of GW and RW affected burning properties of PB positively and an increase of ignition time up to 196% were obtained.
It is aimed to compare the bending strength and modulus of elasticity of end-grain (vertical strip) core blockboard, unlike the usual (lengthwise strip core) blockboard construction, with that of the traditional blockboard with the face-grain or edge-grain core construction. Oriental beech and black poplar woods are provided by taking care to avoid the grain irregularities and visible defects are used in the study. These timbers are used to obtain the core, top and bottom layers of the blockboard. PVAc mounting glue is used for bonding the layers together. According to the test data: The bending strength and modulus of elasticity of oriental beech blockboard are 39% and 26% higher respectively than that of end-grain core black poplar blockboards. If we evaluated by neglecting wood species, strip width was an effective factor in the bending strength and ineffective modulus of elasticity. In addition, the bending strength of the end-grain core oriental beech blockboard is 79 MPa and that of the end-grain core black poplar blockboard is 57 MPa, regardless of the width of the core strip. When these values are compared with the values of other engineered wood, the result is considered open to improvement and satisfactory.
Mechanical properties of wood composites made from multiple wood species (50% Crimean pine, 30% Eastern Black Sea oak, 15% quaking aspen, and 5% wood machining residues) were evaluated using various amount of glass wool (GW) and stone wool (SW) additives. A total of 70 experimental panels were produced with a target density of 640 kg/m3. The bending strength, modulus of elasticity, tensile strength parallel to the surface of boards, tensile strength perpendicular to the surface of boards (internal bond), and cutting (shear) strength parallel to the surface of boards were determined. After statistical analysis, the results indicated that the SW and GW additives decreased the bending strength and modulus of elasticity by 49% in almost all boards. The addition of SW resulted in a 6% reduction in the tensile strength parallel to the surface. Relative to SW, GW resulted in an additional 8% reduction in shear strength, a 3% reduction in the screw tensile strength perpendicular to the surface, and a 6% reduction in the tensile strength parallel to the surface. Thus, the SW and GW additives decreased all the selected mechanical properties of wood composites.
ABSTRACTIn this study, it was aimed to select the most suitable dowelled-leg-and-rail joint (DLRJ) type with multi-criteria decision-making (MCDM) techniques. For this purpose, five types of DLRJ with staggered-rail, flush-rail, lapped-rail, elevated-rail, and mitered-and-lapped-rail were selected as the decision-alternatives and 4-variables consisting of strength, cost, capacity and aesthetics were determined as the decision-criteria. To obtain data, sample tests for the strength values, a work-study analysis for the capacity and cost values, and a questionnaire were performed for the aesthetic superiority values of the joints. In prioritization of the decision criteria and selection and ranking of the alternatives, Criteria Importance through Intercriteria Correlation (CRITIC) + Additive Ratio Assessment (ARAS) hybrid method was used. According to the questionnaire, the most aesthetically pleasing joint was the DLRJ with flush-rail while the DLRJ with lapped-rail was the lowest priority joint type. According to the results of the CRITIC application, strength was the top priority criterion in the selection. The cost, the capacity and the aesthetics followed this respectively. According to the results of the ARAS application, the DLRJ with mitered-and-lapped-rail was optimal while the DLRJ with lapped rail was the last choice option. An increase in the number of criteria, the variables of criteria and the analysis values of these variables are effective factors in the results.KEYWORDS: Furniture jointsDecision variablePurchase decisionConsumer tendencyMCDMDecision aid systems AcknowledgementsThis research was produced from the preliminary data obtained within the scope of the doctoral thesis study that was supported by the Gazi University Scientific Research Projects Unit under grant the project numbered 07/2019-29.Disclosure statementNo potential conflict of interest was reported by the author(s).Declaration of interestsThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.Additional informationFundingThis work was supported by Gazi University: [Grant Number 07/2019-29].
In this study, it was aimed to determine whether or not the layer organizations were influential on the expansion in volume after keeping in water for 2 hours, on the bending strength and modulus of elasticity values of laminated veneer lumber (LVL). Austrian pine (Pinus nigra) (A) and Lombardy poplar (Populus nigra) (B) veneers with thicknesses of 3 mm were used for the production of laminated veneer lumber. A total of 110 test specimens with 8 different layer organizations were prepared by using polyvinyl acetate based (PVAc-D4) adhesive. Solid Austrian pine and Lombardy poplar woods in the same dimensions were used as control specimens. At the end of the tests; the bending strength and modulus of elasticity values of all the LVLs with different combinations were found to be higher compared to the control specimens. The strength characteristics of the LVL increase as the percentage of Austrian pine increases . Key Words: Lamination, Laminated Veneer Lumber (LVL), Bending Strength, Modulus of Elasticity, PVAc Adhesive.
Tuketicilerin ekonomik, sosyal ve kulturel acidan degisip gelismesiyle tuketim aliskanliklari da degismis, hedef pazar yaklasimindaki grubun ortak tercihlerini yansitan urun ozellikleri ile tatmin olmak yerine kendi bireysel beklentilerine uyumlandirilmis urun ozelliklerinden tatmin olmaya baslamistir. Bu durumda uretim sistemleri de degiserek hucresel, esnek veya yalin uretim sisteminden kisisellestirilmis urunlerin uretimini esas alan “kisiye ozel kutlesel uretim/ kutlesel uyarlama” uretim yontemine dayali “Cevik Uretim” sistemine dogru gecis yasanmaktadir. Tuketicilerin bireysel beklentilerine uyumlandirilmis cok farkli urunlerin uretime alinmasi, farkli uretim rotalarinin ortaya cikmasina, makineler arasindaki ara stoklarin artmasina, bazi makinelerin dar bogaz olusturup bazilarinin bos kalmasina, kucuk parti buyuklugu nedeniyle sik araliklarla ayar yapma zorunlulugunun ortaya cikmasina, uretim sureclerinin ve dolayisi ile teslim zamanlarinin uzamasina ve kalitesizlik maliyetlerinin artisina neden olmaktadir. Bu durumda, tuketici memnuniyeti acisindan cok cesitli urunlerin nispeten kucuk partiler halinde daha hizli ve daha dusuk maliyetle uretimini saglayacak makine/teknoloji secimi sorunu ortaya cikmaktadir. Makinelerin seciminde islevsel ozellikler, islevsel yeterliligine bagli islem kalitesi, kapasitesi, isletim maliyeti, denge, servis olanaklari, ekonomik kullanim omru gibi birbiriyle catisan cok sayida parametre olmasi nedeniyle makine secim problemi oldukca karmasik stratejik karar verme problemidir. Bu calismada panel ebatlama makinesi seciminde etkili olan faktorler ve bu faktorlerin onem dereceleri uzman goruslerine dayali olarak tayin edilmis ve cok olcutlu karar destek modeli ile bilgisayar ortaminda AHP (Analitik Hiyerarsi Prosesi) modeli kullanilarak sonuca ulasilmistir.
