Dependence of reaction kinetics and physical and mechanical properties on the reaction systems of acetylation II: physical and mechanical properties

Acetylation of wood was carried out in acetic anhydride only, acetic anhydride/xylene 1:1 (v/v), and acetic anhydride/pyridine 4:1 (v/v) solutions. The antishrink efficiency (ASE), hygroscopic properties, vibrational properties, and bending strength were compared among the three reaction solutions. The ASE was a simple function of weight gain (WG); the equilibrium moisture content at a given WG differed among the reaction solutions. Based on this fact and the results of repeated water soaking and oven-drying tests, it was found that the bulking effect was a major factor, and that decreased hygroscopicity contributes only slightly to the dimensional stabilization by acetylation. The difference in equilibrium moisture content among reaction solutions appears more significant in block samples than wood meal, probably due to the fiber-to-fiber bonds in the former. The tendencies for change in the specific Youngs modulus and the loss tangent differed among reaction solutions, whereas in the static bending test the difference was not marked.Part of this report was represented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002     

Influence of moisture content on the vibrational properties of hematoxylin-impregnated wood

The vibrational property of hematoxylinimpregnated wood was investigated from the aspect of moisture content dependence. The specific dynamic Young's modulus (E/) and loss tangent (tan) of hematoxylin-impregnated wood were determined in the relative humidity (RH) range of 0%–97%, and were compared with those of the untreated and some conventional chemically treated woods. The changes in theE/ and tan of wood with increasing RH were suppressed by acetylation and formaldehyde treatment because of a marked reduction in the hygroscopicity of the wood. Although the hematoxylin impregnation did not significantly affect the hygroscopicity of the wood, its influence onE/ and tan were similar to that of formaldehyde treatment at low RH and of acetylation at medium RH. It was supposed that at low to medium RH hematoxylin restrains the molecular motion of amorphous substances in the cell wall because of its bulkiness and rigidity. On the other hand, at high RH it seems to work as a plasticizer with adsorbed water molecules.     

Vertikalbewegungen Rickettsiose-kranker Larven vonAmphimallon solstitiale (LINNAEUS),Anomala dubia aenea (DE GEER) undMaladera brunnea (LINNAEUS)(Col., Lamellicornia)

Zusammenfassung DurchRickettsiella melolonthae (Krieg) PHILIP infizierte Maikäfer-Engerlinge wandern während des Spätherbstes und Winters im Freiland absterbend auf die Erdoberfläche. Als Begleitarten inMelolontha Larvenpopulationen kamen im Gebiet vor:Amphimallon solstitiale (L.),Anomala dubia aenea (DeG.) undMaladera brunnea (L.). MitR. melolonthae künstlich infiziert, zeigten sie im Orientierungsversuch die gleiche Aufwanderungstendenz wie kranke Maikäferengerlinge, am deutlichsten die vonM. brunnea. Auf dem Waldboden fanden sich kranke Larven dieser Art in einigen Fällen.

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Summary Larvae ofMelolontha spp. infested withRickettsiella melolonthae (Krieg) PHILIP move during October– January to the top of the soil where they eventually die. Larvae ofAmphimallon solstitiale (L.),Anomala dubia aenea (DeG.) andMaladera brunnea (L.) are susceptible forR. melolonthae, too. In experiments, artificially infested individuals showed a similar tendency to move upward. This was most pronounced inM. brunnea, of which some infested larvae were found on the forest floor.

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Résumé Larves du hanneton, infectées parRickettsiella melolonthae (Krieg) PHILIP, se rendent à la surface de la terre au fin de l'automme et dans l'hivers. Comme espèces accompagnant les populations larvaires deMelolontha nous avons trouvés:Amphimallon solstitiale (L.),Anomala dubia aenea (DeG.) etMaladera brunnea (L.). Ils out démonstré, après une infection artificielle avecR. melolonthae, la mème tendence dans les essais d'orientation comme les vers blancs malades deMelolontha. Le phé nomène etait le plus prononcé parmi les larves deMaladera. De cette espèce nous avons trouvés plusieurs larves malades à la surface de la terre en plein champs.

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Rickettsiella melolonthae (Krieg) Philip Melolontha- . . Melolontha- :Amphimallon solstitiale (L.),Anomala dubia aenea (De G.) Maladera brunnea (L.). R. melolonthae , Melolontha-, M. brunnea. .

     

Generationszahl der RübenfliegePegomyia hyoscyami betae Curt.

Summary During the years 1959–1961 the number of generations was followed in Spinach Leaf Miner (Pegomyia hyoscyami betae Curt.) in central Bohemia at 310 m above sea level and in the year 1961 in southern Bohemia at 450 m. The larvae and the eggs were studied on the leaves at regular 10–14 days' intervals by controlling each plant and images by means of a sweeping method. There have been acertained two generations in the year 1959 and three generations in the year 1961 in central Bohemia and two generations in the year 1961 in southern Bohemia. The occurence of every generation of larvae on the suggar-beet was separate and the previous and the consecutive generation did not overlop.The origin of the erroneous date on 6–7 generations of this species (Rambousek, Neuwirth, 1931) has been also cleared up in this article. This statement has been taken over by Sorauer (1953) from the Review of Applied Entomology (1931) and has been lately mentioned by many authors. F. Neuwirth gave a personal information, that the statement on 6–7 generations occurence of Spinach Leaf Miner has been found on the basis of theoretical calculation (from the lenght of one generation in spring and not on the basis of the facts found in natural conditions).

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Résumé En 1959–1961 le nombre des générations de la mouche de la betterave a été observé dans la Bohème Centrale á l'altitude de 310 m audessus de la mer et en 1961 dans le Sud de la Bohème á l'altitude de 450 m. Les larves et les oeufs ont été observé sur les feuilles dans les intervalles de 10–14 jours regulierement effectués sur chaque plante et imagines en particulier par le filet fauchior. En 1959 deux générations et en 1960 et 1961 trios géné rations dans la Bohéme Centrale, ainsi que en 1961 deux générations dans le Sud de la Boheme ont été constates. La prence de chaque génération des larves sur la betterave aété separée et les générations consecutives ne malaient pas presque jamais avec les précedents.Dans cet travail l'auteur a clarifié comment une donnée fautive sur 6–7 générations de cette espéce est survenu (Rambousek et Neuwirth, 1931). Cette donnée orginante de Review of Applied Entomology [1931] a été reprise par Sorauer (1953) et elle a été ensuite récemment mentionée par d'autres auteurs. Selon une déclaration personelle de Mr. F. Neuwirth les donées des 6–7 générations de la mouche de la betterave en Tschécoslovaquie ent été acquis par une évaluation théoretique (se basant sur la durée de la génération du printemps et non sur les resultats des observations réelles dans les conditions naturelles.

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1959–61 . (310 . ) 1961 . (450 . ). 10–14 , . 1959 . 2 , 1960 . — 3, 1961 . — 2 . , . , 6–7 (Rambousek, Neuwirth 1931). . . 6–7 , , .

     

Zum Auftreten einiger Laus- und Käferarfen an Jungkiefern

Summary Larvae ofErnobius spp. and adults ofBrachyderes incanus were serious pests of shoots ofPinus silvestris andP. contorta at several localities of Rhine valley and near Meppen/Ems.In the same areas aphids(Lachninae) and their predators were very abundant.Protolachnus agilis Kltb. became very harmful on young pines in experiment field cages where predators had been excluded.Pineus sp. was frequent in the field cages and in young pine plantations near Meppen.

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Résumé En divers endroits de la vallée du Rhin et près de Meppen/Emsland, des larves d'Ernobius spp. et des adultes deBrachydeles incanus furent observés comme étant de sérieux pour les jeunes pousses dePinus silvestris et deP. contorta.Dans les mêmes régions des pucerons(Lachninae) et leurs prédateurs étaient très abondants.Protolachnus agilis Kltb. divint très nuisible aux jeunes pins placés dans des cages expérimentales où les prédateurs avaient été enfermés.Pineus sp. é tait aussi abondant dans cages expérimentales et dans les plantations de jeunes pins près de Meppen.

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Meppen/Emsland Eronobius spp. Brachyderes incanus, Pinus silvestris P. contorta. (Lachninae) Protolachnus agilis Kltb. , - .Pineus sp. - Meppen.

     

Die neuesten Erkenntnisse der forstlichen Entomologie in der Tschechoslowakei

Summary Present development of forestry entomology in the SSRThis article gives an outline on the occurrence of the more important harmful forest insects in the SSR in the year 1950–1962 and on the results of their study. The Norway spruce suffered from the year 1954 notably byIps typographus L. The control was based on insecticides, studies included optimal density of natural regeneration at the mass propagation etc. It was found, for instance, that typical density borings in bark (151–300 borings per 1 sq.m. of bark) shows variation in the shortest distance between borings from 54–70 mm. Relation between density of borings and their distance indicates function y = a.x^–b, (constant a = 476,9 and constant b= 0,38). It was further found thatIps typographus L. shows even sister generations twice in a year (about 60%, eventually even 30% females of the preceding population). Sister laying is conditioned mainly climatically, i.e. also by the forest stand elevation above sea level. A secure control of further harmful species of Norway spruce,Trypodendron lineatum (Ol.) was carried out by extirpation of wintering beetles in soil, eventually by treating of round wood by emulsions on the HCH + DDT basis.Cephaleia abietis L. shows two diapause periods in a larval stage. For this reason, the development of this species lasts prevailingly two years (90% population). Swarming imagines are controlled by chemical aerosols (10% DDT in the dosis 4–8 kg/ha). On obtained from eggsTrichogramma cephalciae Hochm. et Mart. which cannot be grown on eggs of butterflies. Investigations found that the clean eating ofZeiraphera diniana Guen. begins at the density of 300 caterpillars per one meter of long branch. Chemical control (aerosol 10 l/ha) is recommended when feeding is repeated for three years. The mass propagation ofBupalus piniarinus L. appeared on the Scotch pine. The critical number amounts 400 caterpillars per one kg of needles.Hylobius abletis L. is controlled by insecticides in trap barks and by underground traps for concentration of egg laying. Oak was injuried mostly by the rollerTortrix viridana. The critical number is one caterpillar per one bud. Other, in the SSR new harmful insect of oakArchips crataegana (Hb.) showed the critical number 100 egg heaps on the stem to the height of 2 m. The eggs of the above mentioned species showedTrichogramma embryophagum cacoeciae March., which can easily be grown on butterfly eggs. Oak 60–200 years old was attacked byApethymus biaccatus (Gmel.) andA. abdominalis (Lep.). Silver fir was harmed mainly by the rollerChoristoneura murinana (Hb.). Also the critical number was found. Egg rearing gaveTrichogramma minutum Ril. Ash indicates new type of bark injuries caused probably by a representative of the genusLestes (Fig. 1.). Poplars are damaged by the species of the familyCerambycidae, further byCryptorrhynchus lapathi L. and by the species of the familyAegeridae. Saperda carcharias L. has in the Czechoslovak conditions a generation of three years. Eggs overwinter.Cryptorrhynchus lapathi L. has in the southern Moravia mostly (70% population) one year generation, the rest shows a generation of two years. Beech and hornbeaum were harmfully attacked byErannis aurantiaria Hb.) andColotois pennaria (L.). It is obvious that in the year 1950–1962 several species (Alchips crataegana (Hb.),Apethymus braccatus (Gmel.),A. abdominalis (Lep.) on oak,Erannis aurantiaria (Hb.) andColotois pennaria (L.) on. hornbeam and oak,Pachynematus scutellatus Htg. on Norway spruce etc.) previously not known as important forest injurious insect, appeared as calamity species. Further it is obvious that some harmful insects probably under the influence of changed structure and also forest stand microclimate are retreating whereas other species show mass outbreak. For this reason it is necessary to study the lawfulness of the propagation of the individual species.

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Résumé Les plus récentes expériences de l'entomologie en TchécoslovaquieLe travail contient un aperçu concernant la présence d'insectes nuisibles forestiers de certaine importance en Tchécoslovaquie au cours des années 1950–1962 ainsi que le résultat de leur recherche. Jusqu'à 1954 l'épicéa a été assaili surtout par l'Ips typogiaphus L. On cherche une solution de la défense au moyen des insecticides, la densité optimale d'attaque en cas de la reproduction excessive etc. Par exemple il a été constaté que lors de la densité typique de forage de l'écorce (151–300 forages par mètre carré d'écorce) leur distance ré ciproque varie de 54 à 70 mm. Le rapport entre la densité de forage et de leurs distances présente la forme de fonction y = a.x^–b, où la constante a = 476,9 et la constante b = 0,38. Ensuite il a été constaté qu'en ce qui concerne l'Ips typogiaphus L. existent même deux gé nérations-soeurs au cours de l'année (environ 60 % respectivement encore 30 % des femelles de la population pécédente). La production de pondaisonsoeur est soumis surtout au facteurs climatiques, c'est à dire même á l'altitude des peuplements. Contre un antre parasite de l'épicéa, leTrypodendron lineatum (Ol.), une certaine défense fut élaborée par l'extermination d'imagos hivernant dans le sol ou par le traitement de rondin par des émulsions sur la base HCH + DDT. En ce qui conceme laCephaleia abietis L. on a constaté deux phases de diapause en état de larve. C'est pourquoi le développement duparasite est en majorité biennal (90% de la population). II a été introduit une lutte chimique contre l'essaimage d'imagos par des aerosols (10% de DDT dans une dose de 4 à 8 kg par ha). On a réussi à faire sortir des oeufs de laTrichogramma cephalciae Hochm. et Mart. que l'on ne peut pas cultiver sur les oeufs de papillons. En ce qui concerne laZeiraphera diniana Guen. il fut constaté que la défoliation compléte a lieu par 300 chenilles sur une branche d'un métre de longueur. La lutte chimique est recommandée en cas d'attaque repétée au cours de trois ans. Sur des pins il fut constaté la multiplication de masse duBupalus piniarius L. où le chiffre critique et atteint par 400 chenilles sur un kg d'aiguilles. En ce qui concerne l'Hylobius abietis L. on élabora une manière de défense en utilisant des insecticides dans des pièges d'écorce et des pièges souterrains pour saisir les pondaisons. Sur le chêne c'était laTortrix viridana qui a causé les plus grands dé gâts. Le chiffre critique est exprimé par une chenille pour un bourgeon. En ce qui concerne l'ulté rieur parasite de chêne nouvellement apparu en Tchécoslovaquie, l'Archips crataegana (Hb.), le chiffre critique fut fixé par 100 agglomérations ovulaires sur le tronc jusqu'à 2 mètres de hauteur. On a obtenu laTrichogramma embryophagum cacoeciae March., qui peut être facilement cultivée sur les oeufs de papillons. Sur les chênes d'un âge de 60 à 200 sont apparus ensuite comme parasite desApethymus braccatus (Gmel.) et desApethymus abdominalis (Lep.). Sur le sapin apparaît surtout laChoristoneura murinana (Hb.). Un chiffre critique fut fixé. On a obtenu à partir des oeufs laTrichogramma minutum Ril. On a découvert sur le frêne un nouveau type de lésion de l'é corce provoqué vraisemblablement par la libellule g.Lestes (Fig. 1). Les capricornes, leCryptorrhynchus et lesSesia spp. sont nuisibles aux peupliers. En Tchécoslovaquie laSaperda carcharias L. a une géneration triennale. Les oeufs hivernent. LeCryptorrhynchus lapathi L. a en Moravie du Sud en majorité (70% de la population) une génération annuelle, le restant, biennale. Ensuite sur le hêtre et sur le charme a eu lieu l'apparition désastreuse de la chenille arpenteuseErannis aurantiaria (Hb.) et de laColotois pennaria (L.). Il en ressort donc qu'au cours des années 1950–52 plusieurs espèces ont fait une apparition désastreuse:Archips crataegana (Hb.),Apethymus biaccatus (Gmel.),Apethymus abdominalis (Lep.) sur le chêne,Erannis aurantiaria (Hb.) etColotois pennaria (L.) sur le charme et le hêtre, lePachynematus scutellatus Htg. sur l'épicéa et d'autres qui é taíent auparavent inconnus comme parasites considérables de la forêt.On peut en déduire qu'évidemment sous l'influence de la structure transformée et par consé quent du microclima des peuplements, certains parasites tendent à disparaître, tandis que d'autres insectes deviennent parasites désastreux. C'est pourquoi une recherche approfondie des lois de la reproduction en masse des différentes espèces est nécéssaire.

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- 1950–1962. . 1954. Ips typographus L. , , . . , (151–300 1 ² ) 54 70 . y = a x^–b, a = 476,9 b = 0,38. , Ips typographus L. ( 60%, 30% ). , . . . Trypodendron lineatum (01.) , HCH + DDT. Cephalia abietis (L.) , (90% ). (10% 4–8 (). Trichogramma cephalciae Hochhm. & Mart., . Zeiraphera diniana Guen. 300 1 . . . ( 10 /) . Bupalus piniarius L., 1 400 . Hylobius abietis L. . Tortrix viridana L. 1 1 . , ,Archips crataegana (Hb.) 100 2 . Trichogramma embryophagum cacoeciae March., . 60–200 Apethymus braccatus (Gmel.) Apethymus abdominalis (Lep.). Choristoneura murinana (Hb.). . Trichogramma minutum Ril. - Lestes (. 1). , .Saperda carcharias L. . .Cryptorrhynchus lapathi L. (70% ) , . Erannis aurantiaria (Hb.) Colotois pennaria (L.). , 1950–1962. (Archips crataegana (Hb.),Apethymus braccatus (Gmel.),Apethymus abdominalis (Lep.), Erannis aurantiaria (Hb.) Colotois pennaria (L.), Pachynematus scutellatus Htg. . .), . , , . .

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Herrn Prof. Dipl.-Ing. Dr. A. Pfeffer zum 60. Geburtstag gewidmet.     

Inwiefern könnten Fliegen eine Mittlerrolle bei der Tollwut(Lyssa)-Ausbreitung unter Wild- und Haussäugetieren spielen?

Zusammenfassung Reflexionen zu dem offenen Problem, inwieweit Imagines necrophager Dipteren, — deren Maden im Zentralnervensystem von an Tollwut(Lyssa) verendeten Wirbeltieren zur Entwicklung gelangten —, logischerweise als eventuelle direkte (durch Kontakt-Infektion) oder indirekte (z. B. als Beute von Fledermäusen) Vektoren dieser Virose verdächtigt werden könnten —?

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Summary Reflections belonging the open problem, how far imagines of necrophagous dipters, — if theirs maggots developed in the nervecentre-system of such vertebrats, which succumbed by lyssa —, logically are suspected, perhaps to be vectors of this virose, either directly (by contact-infection) or indirectly (for example to be prey to the bats) —?

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Résumé Rèflexions à ce propos de discuter le problème ouvert, jusqu'à quel point les individues volants des diptères necrophages, — dont mites se developpaient au milieu du système nerveux central de vertébrés, succombés par lyssa —, sont soupçonnés logiquement d'être peut-être des vectors de cette virose, ou directement (par mettre en contact infectieux) ou indirectement (par exemple d'être butin des chirotères) —?

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, , (Imagines), —, , (Lyssa) — ( ) ( ) .

     

Dimensional instability of cement bonded particleboard: Modelling CBPB as a composite of two materials

Previous papers have quantitatively indicated that the total movement of cement bonded particleboard (CBPB) is equal to the sum of the movement of its components. This paper examined the efficacy of the law of mixtures when applied to the movement of a wood-cement composite under internal swelling or shrinkage stresses. Abundant data generated in companion papers were first manipulated to develop the universal formulae for predicting the movement of components. In conjunction with previous numerical results from image analysis of the structure of CBPB, and the orientated elasticity and stress algorithms, the models for theoretically predicting mass and dimensional changes of CBPB were derived. Validation studies were conducted and these demonstrated an excellent agreement of the theoretical predictions with experimental data for both mass and dimensional changes of CBPB due to internal swelling or shrinkage stresses during adsorption and desorption. The success also implied that CBPB can be treated as a composite and its properties can be well derived by the law of mixtures even though CBPB is an unusual type of composite having a very high volume fraction of wood chips, but a very high mass fraction of cement paste.Notation E_RT Mean transverse modulus of elasticity of wood - E_L Longitudinal modulus of elasticity of wood - E_p Modulus of elasticity of cement paste - E_wa Modulus of elasticity of embedded wood chips at angle - E Modulus of elasticity of wood chips at direction - E Modulus of elasticity of wood chips at direction - G_LRT Mean transverse shear modulus of wood - L(T)_cp Length/width (thickness) change of CBPB at angle - L(T)_p Length (thickness) change of cement paste - m_pf Mass fraction of cement paste in unit mass of CBPB - m_wf Mass fraction of wood chips in unit mass of CBPB - M_cpj Mass change of CBPB at the various conditions tested - M_pj Mass change of cement paste at corresponding conditions - M_wj Mass change of wood chips at corresponding conditions - M(L; T)_w/P Mass, length or thickness changes of wood chips or cement paste at various conditions - t Duration of exposure - _LRT Mean transverse Poissons ratio of wood - V_pf Volume fraction of cement paste in unit mass of CBPB - V_wf Volume fraction of wood chip in unit mass of CBPB - _cp Density of CBPB - _k Density of wood chip or cement paste - _cp Overall stresses of CBPB at angle - _L Stress in the longitudinal direction of wood - _RT Mean stress in the transverse direction of wood - _p Stress of cement paste - _w Stress of the wood chips at angle - Stress of the wood chips at direction - Stress of the chip at direction - _cp Strain in CBPB - _p Strain of cement paste - _WL Strain in the length of wood chips - _WT Strain in the thickness of wood chips - _w Strain in wood chips - Angle between the longitudinal direction of wood chips and surfaces or edges of CBPB - Angle between wood chips and edges (length direction) of CBPB - Angle between wood chip and vertical coordinate - A, B, C Coefficients related to the feature of materials and exposure conditions The senior author wishes to thank Professor W.B. Banks of University of Wales, Bangor for his constructive discussions and assistance and the British Council for partly financial support.     

Use of trioxane for improvement of hygroscopic and acoustic properties of wood for musical instruments

Summary As a reagent source for the formalization of wood, trioxane was used instead of conventional paraformaldehyde. From preliminary experiments it became apparent that trioxane depolymerizes to formaldehyde by heating in the presence of some metallic salts. Formalization of wood with trioxane was carried out under the catalysis of sulfur dioxide (SO₂) along with these salts. The hygroscopic and acoustic properties were considerably improved by the treatment. Especially when the reaction was catalyzed by a combination of SO₂ and Fe₂(SO₄)₃, the antiswelling efficiency (ASE) reached nearly 70%, the specific dynamic Young's modulus (E/) in the radial direction increased about 20%, and the loss tangent (tan ) decreased about 30% and 50% in the longitudinal and radial directions, respectively. In this case, the modulus of rupture did not appreciably decrease in the radial direction. This is comparable to the most prominent results obtained so far by SO₂ catalyzed formalization with tetraoxane. It can be concluded that trioxane is very effective as a reagent source for formalization. The increase in acoustic converting efficiency, , of about twofold in the radial direction and decrease in hygroscopicity of more than 60% should not only enrich the sound volume of musical instruments but also stabilize their tone quality against humidity changes.     

Suitability of acetylated woods for clarinet reed

The density (), dynamic Young's modulus (E), loss tangent (tan_L) in the longitudinal (L) direction, and the dynamic shear modulus (G), loss tangent (tan_S) in the LT or LR (T, tangential; R, radial) plane of woods and cane (Arundo donax L.) in air-dried and wet conditions were measured. The acoustic converting efficiency (ACE), expressed by E/³/tan_L, and the factors of anisotropy, expressed byE/G and tan_S/tan_L, of woods were compared with those of the canes. Low-density coniferous woods had higher ACE values and were of a more anisotropic nature than the cane. These woods seemed appropriate for clarinet reed owing to their homogeneous cellular structure. The stability in vibrational properties and the anticreep properties of the woods were enhanced by the acetylation treatment. Professional clarinet players suggested that acetylated Glehn's spruce and sitka spruce were suitable for clarinet reeds.Part of this report was presented at the 48th annual meeting of the Japan Wood Research Society at Shizuoka, April 1998     

Biological performance of wood-based composites treated with a formulation of 3-iodo-2-propynyl butylcarbamate and silafluofen using supercritical carbon dioxide

Wood-based composites (medium density fiberboard, hardwood plywood, softwood plywood, particleboard, and oriented strand board) treated with a mixture formulation of 3-iodo-2-propynyl butylcarbamate (IPBC) and silafluofen using supercritical carbon dioxide as a carrier solvent were evaluated for their resistance to biological attack in a laboratory study. The formulation was pre-pared by mixing 10g of IPBC and 1g of silafluofen in ethanol solution (20ml). Treatments were conducted at 35°C/7.85MPa, 35°C/9.81MPa, and 55°C/11.77MPa with the direct introduction of 20ml of the formulation into the treatment vessel with a capacity of ca. 2000ml at a rate of 2ml/min. Laboratory tests indicated that the treatment conditions used significantly enhanced the resistance of the treated wood-based composites against fungal and termite attacks. Because no significant difference in efficacy against both biodegrading agents was noticed regardless of the treatment conditions, the treatment at 35°C/7.85MPa was thought to be the most economical in terms of energy consumption and performance of treated materials. However, the amount of biocides in a formulation must be carefully selected in accordance with the required treatment condition to ensure satisfactory performance of the treated wood-based composites against any biological agent.     

Hinweise zur Auswirkung biophysikalischer Umweltverhältnisse auf forstschädliche Insekten,untersucht insbesondere anLymantria monacha L.

Zusammenfassung Die Zentren des Schadauftretens verschiedener untersuchter forstschädlicher Insekten dürften nach zahlreichen Testungen Reizzonen umfassen, welche wieder als eine Kombination von elektrischen und magnetischen Feldern und durch diese freigelegte Metalleffekte erscheinen. Untersuchungen zur möglichen Wirksamkeit dieser Komponenten auf Vitalität und Fertilität vonLymantria monacha führten zu folgenden Ergebnissen. Es erscheint möglich, daß innerhalb von Reizzonen Sterblichkeit und Fruchtbarkeit vonLymantria monacha auch von niederfrequenten elektromagnetischen oder auch konstanten magnetischen oder elektrostatischen Feldern beeinflußt werden, die direkt oder auch über die Pflanze auf die Lebenskraft der Nonne von Wirksamkeit sind. Reizzonenbereich und Normalbereich zeigten hinsichtlich der Mortalität der Versuchstiere gegensätzliche Verhältnisse. Die Anfangsmortalität innerhalb von Reizzonen war gegenüber jener der Zuchten im Normalbereich erniedrigt, die Endmortalität vielfach erhöht. Futter aus Normalbereichen setzte in den Reizzonen, Reizzonenfutter im Normalbereich die Sterblichkeit herab und erhöhte im Normalbereich die Fruchtbarkeit. Im Normalbereich mit Normalfutter gezogene Nonnen wiesen die geringsten Zahlen an abgelegten Eiern auf, was sich besonders bei an Pflanzen eingebeutelten Tieren deutlich zeigte. Die wesentlich höhere Fruchtbarkeit von Nonnen an Pflanzen im Reizzonenbereich mag zusammen mit der hier erniedrigten Anfangsmortalität eine Erklärung zum gehäuften Auftreten vonLymantria monacha innerhalb von Reizzonen geben. Freigesetzte Metalleffekte könnten innerhalb von Reizzonen die Sterblichkeit aber auch die Fruchtbarkeit erhöhen.

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Summary The centres of damages by different forest insects, examined in this research, seem to be in zones of Earth radiations (Reizzonen), which again seem to be combinations of magnetic or electric fields and metal effects, set free by them. Examinations for possible influences of these components on vitality and fecundity ofLymantria monacha showed the following results: It seems possible, that inside of zones of earth radiations mortality and fecundity of this butterfly could be directed from magnetic or electric fields also of low frequency or electrostatic, which either directly or indirectly by the nutrients (plants) influence the vital power ofLymantria monacha. Zones of Earth radiations and normal zones showed different conditions in respect of the mortality. Mortality of larvae of first developmental stages inside of zones of Earth radiations was decreased, such of late stages increased contrary to larvae in normal zones. Plant-food of normal zones decreased the mortality of larvae in zones of Earth radiations and food of zones of Earth radiations decreased the mortality of those of normal zones and increased fecundity in the latter cases. Female butterflies reared in normal zones showed the lowest number of developed eggs, especially when reared encaged on living plants (spruce). The essentially higher fecundity ofLymantria monacha reared on plants inside of zones of Earth radiations together with the decreased mortality of first instar larvae there, may give an explantation for the increased population ofLymantria monacha inside of zones of Earth radiations. Metal effects set free inside of zones of Earth radiations could increase there the mortality but also the fecundity.

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Herrn Prof. Dipl.-Ing. Dr. ERWIN SCHIMITSCHEK zum 75. Geburtstag.

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A 1130 Wien XIII, Fasangasse 5-7, 1/8     

Changes in the physical and chemical properties of six Japanese softwoods caused by lengthy smoke-heating treatment

The effects of prolonged smoke-heating treatments on wood quality were investigated. Six Japanese softwoods were smoke-heated for 100 and 200h at a temperature of 75° ± 5°C, which was recorded inside the log. After smoke heating, wood quality, including moisture content, amounts of chemical components, relative degree of crystallinity (RDC) of cellulose, and sapwood color were examined. Moisture content decreased as a result of smoke heating, especially in sapwood, leading to a uniform distribution of moisture content within a log. Almost no difference was found in the amounts of chemical components between the control woods and the woods that were smoke-heated for 100h. However, in the wood that was smoke-heated for 200h, the amounts of holocellulose decreased, suggesting that thermal deterioration and/or degradation of hemicelluloses had occurred. We assume that the increase in RDC was caused by smoke heating with the crystallization of cellulose and/or thermal degradation of hemicelluloses. Almost no differences were found in sapwood color between the control woods and the woods that were smoke-heated for 100h. In the wood that was smoke-heated for 200h, however, L*decreased, whereas a* and b* increased. As a result, E*ab, showing the total color change, increased, resulting in a deeper color. These results suggest that thermal degradation of hemicelluloses was caused by smoke heating for over 100h. Therefore, smoke heating of softwood logs using a commercial-scale kiln should not exceed 100h.     

Defining competition vectors in a temperate alley cropping system in the midwestern USA: 2. Competition for water

A study was carried out in an alley cropping system in the Eastern Maize Belt of the United States with the objective of quantifying the competition for water between trees (black walnut (Juglans nigra L.) and red oak (Quercus rubra L.) and maize (Zea mays L.). Spatial and temporal variation in soil moisture, tree and maize rooting patterns, tree and maize water uptake, and maize leaf area expansion were determined in three treatments; barrier (polyethylene root barriers separating maize and tree roots), trench (trenching without a polyethylene barrier), and no barrier (control). Significant temporal variation in soil moisture was observed in both black walnut and red oak alley cropping systems. The barrier and trench treatments resulted in higher soil moisture in the maize alley and lower soil moisture in the tree row than the no barrier treatment. Uptake of water by maize was higher in the barrier than the no barrier treatment. However, tree water uptake was higher in the no barrier treatment than in the barrier treatment because tree roots utilized water from the maize alley. Maize leaf area was negatively impacted by water stress in the no barrier treatment. Quantification of rooting patterns revealed that maize and tree roots were concentrated in the top 30 cm soil layer where water fluctuations were greatest. The barrier and trench treatments successfully eliminated the belowground root competition between trees and maize and resulted in greater leaf area and higher grain yields than the no barrier treatment. Thus, competition for water rather than competition for light seems to be critical in defining the productivity and sustainability of this alley cropping system.This revised version was published online in November 2005 with corrections to the Cover Date.     

Two lignan rhamnosides from birch leaves

The extractives of shirakamba (Betula platyphylla Sukatchev var.japonica Hara) leaves were investigated. Two lignan glycosides were isolated, and their structures were elucidated to be 1-(4-hydroxy-3-methoxyphenyl)-2-[1-(3--l-rhamnopyranosyloxypropyl)-3-hydroxyphenoxy]-1,3-propanediol (I) and a new 2,3-dihydro-2-arylbenzofuran configuration neolignan,cis-2,3-dihydro-2-(4--l-rhamnopyranosyloxy-3-methoxyphenyl)-3-hydroxymethyl-7-hydroxy-5-benzofuranpropanol (II). These neolignan rhamnosides were newly found in shirakamba.     

Effect of impregnation on mechanosorption in wood and paper studied by dynamic mechanical analysis

The results of dynamic mechanical measurements in dual cantilever and uniaxial tension of untreated Scots pine veneer and unbleached sulphate paper under stepwise changes in the relative humidity of the surrounding atmosphere between 5% and 85% are compared to corresponding results for acetylated samples and samples treated by impregnation with poly(ethylene oxide) (PEO), glycerol or melamine formaldehyde resin. The treatments resulted in significant reductions in the transient mechanical losses associated with stepwise humidity changes. Although acetylation of wood and impregnation with PEO or glycerol both result in greatly improved dimensional stability with respect to humidity changes, the two types of treatment appear to be fundamentally different in terms of the models used here to interpret the results.We find that it is helpful to consider the dynamic process of moisture sorption/ desorption in these samples in terms of two coupled processes: the diffusion of moisture into or out of the sample, with a characteristic diffusion time given approximately by t^* = /16)h²/D where h is the sample thickness and D a characteristic diffusion constant for the moisture in the material, and the attachment/detachment of (clusters of) water molecules to binding sites in the samples, apparently with characteristic chemical relaxation times of the order of seconds or minutes. Clearly, when the sample thickness is quite small, 0.8 mm in our case, and the diffusion coefficient of the order of 50 × 10^–8 cm²/s, then the characteristic diffusion time is about 40 minutes, already for these small dimensions more than an order of magnitude larger than the characteristic chemical relaxation time. By varying the frequency of the dynamic mechanical measurements these characteristic processes for untreated and treated samples can be probed in some detail.     

Effect of collar insertion on soil respiration in a larch forest measured with a LI-6400 soil CO2 flux system

Little information is available on the effect of root cutting by the collar pre-insertion technique on soil respiration. In this study, we found that soil respiration rates decreased with increasing depth of collar insertion in both the with live roots intact and with live roots severed treatments, but the rate of decrease was substantially higher in the former. The cutting of roots, especially fine roots, may be responsible for this result.     

Studies on the synthesis and properties of terpene-phenol-aldehyde resin with a high softening point

Synthesis conditions of terpene-phenol-aldehyde resin with a high softening point were studied based on the reactions among-pinene, phenol, and formaldehyde. A suitable catalyst system and the best processing conditions were obtained by laboratory experiments. The influence of the raw materials ratios, reaction temperature, reaction time, and catalyst dose on the softening point, yield, and color of the synthesized resin was examined. The physical and chemical characteristics of the resin were determined: softening point 140°C (ball and ring method); color value 7 (Gardner); acid value (KOH mg/g) <1; bromine value (Br₂ mg/100g) <64; saponification value (KOH mg/g) <1; average molecular weight 830. The yield of resin was more than 85% (based on the total raw material).     

Manufacture and properties of low-density binderless particleboard from kenaf core

Low-density binderless particleboards from kenaf core were successfully developed using steam injection pressing. The target board density ranged from 0.10 to 0.30g/cm³, the steam pressure used was 1.0MPa, and the steam treatment times were 7 and 10min. The mechanical properties, dimensional stability, and thermal and sound insulation performances of the boards were investigated. The results showed that the low-density kenaf binderless particleboards had good mechanical properties and dimensional stability relative to their low board densities. The board of 0.20g/cm³ density with a 10-min treatment time produced the following values: modulus of rupture 1.1MPa, modulus of elasticity 0.3GPa, internal bond strength 0.10MPa, thickness swelling in 24h water immersion 6.6%, and water absorption 355%. The thermal conductivity of the low-density kenaf binderless particleboards showed values similar to those of insulation material (i.e., rock wool), and the sound absorption coefficient was high. In addition, the boards are free from formaldehyde emission. Kenaf core appears to be a potential raw material for low-density binderless panels suitable for sound absorption and thermally resistant interior products.Part of this report was presented at the 52th Annual Meeting of the Japan Wood Research Society, Gifu, Japan, April 2002     

Poisson’s ratios of an oriented strand board

In the assessment of the structural adequacy of oriented strand board (OSB) members by design calculation, the need for the boards Poissons ratios often becomes evident. However, mention of Poissons ratios as a relevant mechanical property is seldom made in wood-based panel test and design standards. The short-term principal Poissons ratios of a typical OSB has been determined from tension tests. Mean values of 0.23 and 0.16 have been obtained for the major and minor Poissons ratios, respectively. The experimentally determined Poissons ratios appear consistent with the values estimated from the panel shear and tension moduli of elasticity. Complementary values of the Poissons ratios in bending have been estimated from the bending moduli of elasticity and tension test results for the panel. Efficiency in the assessment of OSB by design calculation follows from knowledge of Poissons ratios. However, for this benefit to be realised in routine design, the Poissons ratios of structural grade OSB need to be available.