Utjecaj materijala za oblaganje na svojstva posmičnog zida od furnirske ploče

Wooden buildings are intensely preferred especially in earthquake regions due to their many advantages such as lightness, durability, environmental friendliness, insulation and aesthetics. Shear walls provide the lateral resistance needed for light-frame wood structures to withstand earthquake loads. When sheathed with wooden structural panels such as plywood, shear walls can be strong, stiff, and ductile. This study focuses on the effects of production factors (wood species, thickness of panels) of plywood and fibre direction of sheathing material on the racking performance of the shear wall. The displacement at ultimate load decreased with increasing the thickness of plywood panels. It was also concluded that the black pine plywood panels were the best sheathing materials for the shear walls among wood species in terms of ductility. Scots pine plywood panels are the best sheathing materials for the shear walls among wood species in terms of load carrying capacity. Moreover, it was found that the wall formed perpendicular to fibre direction of sheathing materials could carry more load than the wall formed parallel to fibre direction.U potresnim su područjima osobito zastupljene drvene građevine zbog njihovih brojnih prednosti kao što su lakoća, trajnost, ekološka prihvatljivost, izolacija i estetika. Posmični zidovi osiguravaju bočnu otpornost kako bi lagane drvene konstrukcije izdržale potresna opterećenja. Kada su obloženi drvenim strukturnim pločama kao što je furnirska ploča, posmični zidovi mogu biti jaki, kruti i duktilni. Ovo je istraživanje fokusirano na učinke proizvodnih čimbenika furnirske ploče (vrstu drva, debljinu ploče) te na smjer vlakanaca materijala za oblaganje na svojstva posmičnog zida. Pokazalo se da se s povećanjem debljine furnirske ploče smanjuje pomak pri krajnjem opterećenju. Također je zaključeno da su sa stajališta duktilnosti furnirske ploče od drva crnog bora bolji izbor za oblaganje posmičnih zidova nego furnirske ploče od ostalih istraživanih vrsta drva. Sa stajališta nosivosti, za oblaganje posmičnih zidova najboljima su se pokazale furnirske ploče od drva bijelog bora. Osim toga, utvrđeno je da zid formiran okomito na smjer vlakanaca materijala za oblaganje može nositi veće opterećenje nego zid formiran paralelno sa smjerom vlakanaca materijala za oblaganje

Predviđanje optimalne gustoće ekspandiranog polistirena za najbolje performanse toplinske izolacije polistirenske kompozitne iverice primjenom umjetne neuronske mreže

The objective of this study is to predict the optimum expanded polystyrene (EPS) densities for the best insulation properties of the particleboards manufactured with waste EPS instead of formaldehyde-based adhesives used in particleboard production with artificial neural network (ANN). For this purpose, the waste EPS particles of five different densities were used in the production of composite particleboards. The experimental dana used in the study were obtained from the previous study. Half of the beech, poplar, alder, pine and spruce chips were dried in a drying oven and the other half were naturally conditioned at room temperature, and then 18 mm thick three-layer composite particleboards were produced. The thermal conductivity of panels was determined according to ASTM C 518. The prediction model with the best performance and acceptable deviations was determined by using statistical and graphical comparisons between the experimental data and the prediction values obtained as a result of ANN analysis. Then, using this prediction model, the thermal conductivity coefficient values were estimated for the intermediate EPS densities that were not experimentally tested. According to the analysis findings, the thermal insulation performance for both beech and spruce polystyrene composite particleboards (PCP) panels increased with using of waste EPS foams with a density of 30 kg/m3. The lowest thermal conductivity values were obtained from the EPS waste foams with the density of 18, 13 and 22 kg/m3 for the PCP panels produced with poplar, alder and pine in the natural drying, respectively. In the technical drying, these values were found to be 15, 14 and 11-13 kg/m3, respectively. Technical drying showed much better thermal performance than natural drying while poplar indicated the best performance among the wood species.Cilj je ove studije primjenom umjetne neuronske mreže (ANN) predvidjeti optimalne gustoće ekspandiranog polistirena (EPS) radi postizanja najboljih izolacijskih svojstava iverice proizvedene s otpadnim EPS-om umjesto s ljepilom na bazi formaldehida, kakvo se rabi u proizvodnji iverice. Stoga je za proizvodnju iverice upotrijebljen otpadni EPS pet različitih gustoća. Eksperimentalni podatci primijenjeni u studiji dobiveni su prijašnjim istraživanjem. Jedna je polovica iverja bukovine, topolovine, johovine, borovine i smrekovine osušena u sušioniku, a druga je polovica iverja kondicionirana na sobnoj temperaturi. Od osušenoga i kondicioniranog iverja proizvedene su troslojne kompozitne iverice debljine 18 mm. Toplinska vodljivost ploča određena je metodom ASTM C 518. Predikcijski model najboljih svojstava i prihvatljivih devijacija određen je statističkom i grafičkom usporedbom eksperimentalnih podataka s vrijednostima predviđenima ANN analizom. Potom su primjenom predikcijskog modela procijenjeni koeficijenti toplinske vodljivosti za one gustoće ekspandiranog polistirena koje nisu eksperimentalno ispitane. Prema toj analizi, termoizolacijska svojstva polistirenske kompozitne iverice (PCP) od bukovine i smrekovine poboljšana su pjenom od otpadnog EPS-a gustoće 30 kg/m3. Najniže vrijednosti toplinske vodljivosti za polistirensku kompozitnu ivericu od prirodno osušene topolovine, johovine i borovine dobivene su uz uporabu pjene otpadnog ESP-a gustoće 18, 13 i 22 kg/m3. Za polistirensku kompozitnu ivericu od tehnički osušenog iverja te su vrijednosti bile 15, 14 i 11-13 kg/m3. Tehničkim sušenjem iverja postignuta su znatno bolja toplinska svojstva polistirenske kompozitne iverice nego prirodnim sušenjem, a topolovina je pokazala najbolja svojstva od svih ispitivanih vrsta drva

The effects of contract mechanisms between the government and private hospitals on the social utility

In this work, we deal with a real healthcare system, in which public and private hospitals with different characteristics co-exist. While public hospitals have lower costs, they also suffer from long waiting times, diminishing the perceived quality of care for patients. Conversely, private hospitals, with their higher fees, offer shorter waiting periods, resulting in a more favorable perception of quality. A balanced healthcare system could offer societal benefits. Pricing strategies greatly influence a patient's hospital selection. For instance, reduced fees in private hospitals attract more patients, consequently reducing overcrowding in public facilities and elevating the overall quality of services provided. This study aims to develop pricing models to foster a balanced and socially advantageous healthcare system. Within this system, private hospital pricing is determined through contract mechanisms with the government. Thus, we delve into the ramifications of various contract models between the government and private hospitals on social utility. Our findings underscore the communal advantages of contract mechanisms. Furthermore, we generalize the proposed models to be applicable to similar systems.info:eu-repo/semantics/publishedVersio

Comparison of thermal performances of plywood shear walls produced with different thermal insulation materials

Shear walls are one of the envelopes of light-frame wooden buildings where thermal insulation is most required. The thermal performance of shear walls can vary according to the type, properties and thickness of the wood and insulation materials used in their production. In this study, it was aimed to compare the thermal performances of plywood shear walls produced with different thermal insulation materials. For this aim, the archetype walls with properties similar to commonly used plywood shear walls were designed and produced for each thermal insulation material type and wood specie. The shear wall groups were formed by using Scots pine (Pinus sylvestris), black pine (Pinus nigra) and spruce (Picea orientalis) as wood species and cellulose, flax, felt, XPS, EPS, sheep’s, rock and glass wool as thermal insulation materials. Thermal conductivity of the shear wall groups was determined according to the ASTM C518-04 standard. Thermal resistance and other thermal performance parameters were calculated using the thermal conductivity values. As a result of the study, rock wool was the best thermal insulation material among the Scots pine shear wall groups while glass wool was the best thermal insulation material among the black pine and spruce shear wall groups. The shear walls produced with EPS foam boards indicated the worst thermal performance among all group

Oslobađanje formaldehida iz uslojene drvene ploče proizvedene od furnira obrađenih usporivačima gorenja i lijepljenih dvama tipovima urea-formaldehidnih ljepila

In the present study, it was aimed to investigate the formaldehyde release of plywood panels manufactured from beech, poplar, alder and scots pine veneers treated with 5 % aqueous solutions of commonly used fire retardants: zinc borate, boric acid, monoammonium phosphate and ammonium sulfate. Two types of urea formaldehyde (UF) resin with different free formaldehyde ratios (0.16 % and 0.20 %) in adhesive were used as adhesive. Formaldehyde release of plywood panels was determined according to fl ask method described in EN 717-3 standard. As a result of this study, it was found that formaldehyde release from panels produced by beech, poplar, alder and scots pine veneers treated with zinc borate and boric acid were higher than those of control panels, while lower formaldehyde release was obtained for panels treated with monoammonium phosphate and ammonium sulfate. This is valid for all four wood species. Treatment of monoammonium phosphate and ammonium sulfate caused considerable reduction in formaldehyde emission from manufactured plywood panels. In some usage areas, where high strength properties are not expected, plywood panels manufactured from veneers treated with monoammonium phosphate and ammonium sulfate may be used for reducing formaldehyde release.U radu je predstavljeno istraživanje oslobađanja formaldehida iz uslojenih drvenih ploča proizvedenih od furnira bukve, topole, johe i običnog bora tretiranih s 5 %-tnim vodenim otopinama najčešće upotrebljavanih usporivača gorenja: cinkova borata, borne kiseline, monoamonijeva fosfata i amonijeva sulfata. Za lijepljenje furnira upotrijebljene su dvije vrste urea-formaldehidnog ljepila (UF) različitog omjera slobodnih formaldehida (0,16 i 0,20 %) u njemu. Oslobađanje formaldehida iz uslojenih drvenih ploča određeno je perforatorskom metodom opisanom u standardu EN 717-3. Istraživanja su pokazala da je oslobađanje formaldehida iz uzoraka ploča proizvedenih od furnira bukve, topole, johe i običnog bora i tretiranih cinkovim boratom i bornom kiselinom veće nego iz kontrolnih uzoraka ploča, dok je za ploče tretirane monoamonijevim fosfatom i amonijevim sulfatom ustanovljena manja količina oslobođenog formaldehida. To vrijedi za sve četiri vrste drva. Tretiranje ploča monoamonijevim fosfatom i amonijevim sulfatom rezultirala je znatnim smanjenjem emisije formaldehida iz proizvedenih uslojenih drvenih ploča. Stoga se u nekim područjima uporabe u kojima se ne zahtijeva velika čvrstoća ploča mogu upotrebljavati ploče od uslojenog drva izrađene od furnira tretiranih monoamonijevim fosfatom i amonijevim sulfatom jer se iz njih oslobađaju manje količine formaldehida

On the efficacy of a novel optimized tuned mass damper for minimizing dynamic responses of cantilever beams

This study examines the optimal design of a tuned mass damper (TMD) in the frequency domain so that the dynamic response of cantilever beams can be decreased. Random vibration theory is applied to identify the mean square acceleration of the endpoint of a cantilever beam as the objective function to be reduced. In addition, to determine the optimal TMD coefficient of mass, stiffness, and damping, a differential evolution (DE) optimization algorithm is employed. The upper and lower limit values of these parameters are taken into account. A majority of the previous studies have concentrated on determining just the stiffness and damping parameters of TMD. Nonetheless, in this study there is also the optimization of TMD mass parameters to determine the mass quantity. In addition, there has been inefficient use of the stochastic DE optimization algorithm method for the optimization of TMD parameters in previous studies. Hence, to obtain optimal TMD parameters, this algorithm is precisely used on the objective function. Tests are carried out on the cantilever beam with the TMD system following this optimization method with harmonic base excitations that resonate the foremost modes of the beam and white noise excitation. The method proposed here is reasonably practical and successful regarding the optimal TMD design. When a TMD is designed appropriately, the response of the cantilever beam under dynamic interactions undergoes a considerable reduction

Utilization of Colemanite waste in Concrete Design

Waste material is formed in enormous quantities during the beneficiation of raw ore. These wastes can cause both economic loss and environmental pollution. Thus, in this study, the effect of CW obtained from Eti Mine Establishments Kütahya-Emet Boron Plants on the compressive strength and cylinder splitting tensile strength of concrete and its USAbility as a concrete admixture is investigated. The results found show that utilization of Colemanite Waste is possible when it is used as additive in concrete

The prevelance of human papillomavirus (HPV) genotypes detected by PCR in women with normal and abnormal cervico-vaginal cytology

Objectives: Cervical cancer is the second most common type of cancer for women worldwide with a great proportion proved to be related to human papillomavirus (HPV) infection. As infection with HPV is the strongest risk factor for cervical neoplasia, detection of HPV genotypes in cervical and vaginal specimens of women with normal and abnormal cytology seems to be of paramount importance in cervical cancer screening. The objective of the study is to evaluate the prevalence and HPV genotypes among women with normal or abnormal Pap smear tests. Material and methods: This retrospective study was conducted in a tertiary care university hospital in western Turkey. A total of 201 patients in whom both HPV typing and Pap test was performed between 2012 and 2016 in our obstetrics and gynecology department were enrolled in this study. Clinical and laboratory data were obtained for all participants. Cervical smears of the patients were classified by the Bethesda system and HPV analyses were done using the polymerase chain reaction (PCR) method. Results: This study included 201 women, 72 of whom had normal and 129 of whom had abnormal Pap smear results. HPV DNA was detected in 91 (45.2%) of the 201 investigated women. Out of 72 patients with normal cervico-vaginal cytology, HPV positivity was detected in 35 (49%) patients, whereas 33 (35%) patients out of 94 with ASCUS , 18 (62%) patients out of 29 with LSIL and 5 (83%) patients out of 6 with HSIL had HPV positivity. Out of 35 HPV positive women that had normal pap test results, 25 (75%) were found to have high risk HPV (HR-HPV) genotypes. In women with ASCUS, LSIL and HSIL, HR-HPV genotype rates were found to be 94%, 89% and 100% respectively. The most common identified HPV types were HPV58, HPV16, HPV31, HPV33, HPV11 and HPV35. Conclusions: The frequency of HPV infection was found to be higher in our study compared to previous reports. Moreover, although HR-HPV genotypes were also detected in patients with normal cervical cytology, a majority of patients with HR-HPV genotypes were associated with abnormal cervical smear cytology including high rates of atypical squamous cells of undetermined significance, low-grade squamous intraepithelial lesion, and high-grade squamous intraepithelial lesion

Utjecaj procesa sušenja furnira na tehnološka svojstva kompozitnih uslojenih drvnih ploča vezanih polistirenom

The aim of study was to determine the effect of veneer drying process on some technological properties of polystyrene composite plywood panels. For this reason, 2 mm-thick rotary cut veneers were obtained from beech (Fagus orientalis, Lipsky), Alder (Alnus glutinosa subsp. Barbata) and Scots pine (Pinus sylvestris L.) logs. The veneers obtained from three different wood species were divided into two groups to produce polystyrene composite plywood (PCP) and traditional plywood. While PCP was produced both air dried (at 20 °C) and oven dried (at 110 °C), the veneer sheets for production of traditional plywood were dried at 110 °C until reaching 7 % equilibrium moisture content. Two different types of polystyrene with high density (30 kg/m3) and low density (16 kg/m3) were used as bonding material for PCP panel production. The urea-formaldehyde adhesive was used as a bonding material for traditional plywood panels. Bonding shear strength, bending strength, modulus of elasticity and density of plywood and polystyrene composite plywood panels were investigated. It was found that the technological properties observed in the study of composite plywood panels manufactured with natural dried veneers gave similar results compared to those of composites produced with technical dried veneers.Cilj ovog istraživanja bio je utvrditi utjecaj procesa sušenja furnira na tehnološka svojstva kompozitnih uslojenih drvnih ploča vezanih polistirenom. Ljušteni furniri debljine 2 mm pripremljeni su od trupaca drva bukve (Fagus orientalis, Lipsky), drva johe (Alnus glutinosa subsp. Barbata) i drva običnog bora (Pinus sylvestris L.). Furniri od tri različite vrste drva podijeljeni su u dvije skupine kako bi se proizvela kompozitna uslojena ploča vezana polistirenom (PCP) i tradicionalna uslojena ploča. Za proizvodnju PCP ploča rabljeni su furniri sušeni na zraku (na 20 °C) i u sušioniku (na 110 °C), a za proizvodnju tradicionalne uslojene ploče upotrijebljeni su furniri sušeni pri 110 °C sve do postizanja ravnotežnog sadržaja vode od 7 %. Kao vezivo za PCP ploče uporabljene su dvije vrste polistirena – polistiren velike gustoće (30 kg/m3) i polistiren male gustoće (16 kg/m3). Za proizvodnju tradicionalne uslojene ploče kao vezivo je služilo urea-formaldehidno ljepilo. Istraživani su smična čvrstoća lijepljenog spoja, čvrstoća na savijanje, modul elastičnosti te gustoća uslojene i kompozitne uslojene ploče vezane polistirenom. Utvrđeno je da kompozitne uslojene drvne ploče proizvedene od prirodno sušenih furnira imaju slična promatrana tehnološka svojstva kao i kompoziti proizvedeni od tehnički sušenih furnira

Effects of plasma surface treatment on bending strength and modulus of elasticity of beech and poplar plywood

This is a study on the effect of plasma treatment with different gases and plasma intensity on the bending strength and modulus of elasticity of plywood manufactured from beech and poplar. Oxygen (O2) and ammonia (NH3) plasma were applied on the veneer sheets; two plasma intensities were applied on the veneers with 150 and 300 W in the plasma chamber during one minute. Phenol formaldehyde resin was applied on one surfaces of each veneer with approx. 160 g/m2. Bending strength and modulus of elasticity were determined according to EN 310.The effects of plasma surface treatment on chemical structure of the panels were determined with FTIR-ATR analysis. Bending strength of all tested panels slightly and partly increased without statistical significance when applying oxygen plasma. The effect of ammonia plasma treatment on bending strength and was determined by the wood species and the plasma intensity, and it was not uniform. Modulus of elasticity of the panels with oxygen plasma treatment showed in most cases improvement, whereas ammonia plasma pretreated veneers caused lower values compared to the control panels