Urethane Foam Research Articles

A Study on Fire Hazards in Multiple Compartments with Lightweight Partition Walls

This paper presents the study of a fire risk to the backside of two miniatures of ISO 9705 2/5 using a lightweight partition for indoor space division and reproduction of the ISO 9705 test. An SGP partition, stud partition, glass wool panel, urethane foam panel, sandwich panel, and glass partition were selected as the test specimens, which are frequently used in construction. According to the ISO 9705 test standard, stabilization was achieved using a measuring device that recorded data before the ignition of a burner and continued recording for 120 s thereafter. After ignition was achieved, the power was increased to 300 kW for 600 s and then reduced to 100 kW for 600 s. The specimens were subsequently observed for 180 s, and the fire risk to the backside and the fire pattern of the wall unit were analyzed. Owing to the amount of heat generated by the ignition source, the maximum temperature of the backside was observed to be 67.7 ℃ for the SGP partition, 55.1 ℃ for the stud partition, 52.4 ℃ for the glass wool panel, 727.4 ℃ for the sandwich panel, 561 ℃ for the urethane foam panel, and 630.5 ℃ for the glass partition. In the cases of the sandwich and urethane foam panels, the explosion of flammable gas occurred by virtue of fusion of the interior materials. The reinforced glass was fractured owing to the temperature difference between the heat- and nonheat-responsive parts. Ultimately, the fire risk to the nearby section room was deemed to be high.

Performing Manufacturer Mitigates Risk by Using Performance Information Systems

A manufacturer initially approached the researchers to identify how to use the performance information of their high-performance urethane coating system to increase quality. The research project used the construction industry structure to identify owners who understood the high risk and transactions caused by low bid practices. Intelligent owners understood that value was delivered by expert contractors using high performance products rather than warranties. However, during the economic downturn, high performing contractors reverted to the low bid practices of using warranties to win work rather than performance. To create a high-performance environment, the manufacturer again approached the researchers to mitigate the risk caused by their warranties. The research identified that risk was not mitigated by warranties, but by transparency and performance information. A structure was developed that mitigated risk caused by a change in paradigm that resulted in a "win-win" result in a test case that involved the school district. As the system was installed, the performance of contractors increased, and the sprayed urethane foam contractors became the only roofing contractors at the school district to consistently maintain their installed roofs and mitigate the risk to the client at their own cost without using the manufacturer's warranty.

Using foam polyurethane sealers for strengthening of soils of a road bed of transport constructions

The article presents an overview of the methods of producing alternative building materials by strengthening soils with organic binders based on synthetic resins. Their use in road construction would meet the needs of construction organizations in high-quality building materials and ensure reliable operation of soil masses of subgrade road transport structures throughout estimated service life. The authors proposed a new, alternative method for soil stabilization using urethane foam sealants, which have proven themselves in civil engineering in the form of mounting foams. The paper describes a method for strengthening soil with sealants, its labor production technology, properties and physical and mechanical characteristics. The results of the trial experience of soil strengthening with polyurethane foam sealant are described and conclusions are made based on the work.

Flame retardant and mechanical properties of expandable graphite/polyurethane foam composites containing iron phosphonate dopamine‐coated cellulose

AbstractAdditive‐type flame retardants used in polyurethane foams (PUFs) have low compatibility with the matrix and have a large particle size which reduces the mechanical strength. To overcome this, cellulose‐based additive‐type flame retardants were prepared. Microcrystalline cellulose (MCC) was grinded to a suitable size to be applying as a reinforcement for urethane foam. The ground MCC was coated with the mussel‐derived adhesive protein, dopamine, and formed the iron phosphonate coordination network on the surface. It was confirmed that the modification proceeded well by structural analysis by Fourier‐transform infrared spectrometer and morphology analysis by scanning electron microscope. In the synthesis of PUF, expandable graphite (EG) was added to obtain high flame retardancy. The PUF mixed with 3 wt% of ground MCC‐based flame retardant and 12 wt% of EG (GCF3) was found to have an excellent limiting oxygen index (LOI) of 25.3%, while the LOI of pure PUF was 19.3%. In particular, the compressive strength of GCF3 was remarkably enhanced (21 wt%) compared with the PUF containing 15 wt% of EG. This study produced a new additive‐type flame retardant to improve mechanical strength. This provides a simple and comprehensive solution for PUF applications requiring high flame retardancy and mechanical strength.

Eliminating Fastener Thermal Bridging in Low Slope Roofs: Energy Efficiency Savings versus Installation Costs

Low-slope roofing assemblies include a wide range of insulation and single ply membrane attachment methods. Previous studies have shown that mechanical attachment using metal fasteners leads to significant thermal bridging and consequent loss of insulation value and reduction of long term thermal efficiency. This study calculates the costs associated with mechanical attachment in terms of lost insulation value, increased long-term energy costs, and the material and labor costs associated with installation of these common systems. Energy efficiency reductions using metal fasteners were modeled for eight US cities in a range of climate zones. From the data, it was possible to calculate target costs (labor plus materials) that would make adhered systems cost effective. There are many options available to adhere single ply roof system components, such as solvent-based adhesives and low-rise urethane foams, together with different application approaches such as broom, spray, and ribbon methods. The cost targets derived in this study can help optimize the use of such materials and application methods such that the thermal bridging due to fasteners could be substantially reduced or eliminated.

Effect of drilling parameters on natural fiber reinforced with chaired epoxy poly urethane foam composites using grey relational analysis

This modern trend of industrial development and technological update, composites have greater requirement in many structures to be built. Composites are replacing many materials that are being used traditionally for particular need, this is because of their exemplary properties they posses as a composite unit, as they are frequently used in many applications in many fields (automobiles, aerospace, building structures etc) so there is a incite starve to study about material behavior, efficient machining methods, machining parameters and mechanical properties of composites. There are many machining methods that are implied on composites, one of them is drilling; To drill a composite, the material behavior need to be understood and then drill the composites as they are heterogeneous mixture and materials used in composites has different properties as individual ,so this work is all about the study of drilling composites and their drilling parameters [feed rate (mm/min),speed of spindle(rpm),drill diameter] are imputed and later their influence on the thrust force and torque are analyzed. With the help of Taguchi technique, and Grey relational method multiple drill parameters are being optimized to ease the experiments. The enclosure of this experiment is that the diameter of drill bit has the major effect on the output characteristics

Influence of Sparse Contact Point and Finger Penetration in Object on Shape Recognition.

Making a virtual object shape recognizable using a haptic display is one of the major themes of haptic research. In previous works, multipoint haptic displays have been developed that had a high contact point density between the users' finger skin and the virtual object. However, the ideal contact point density that enables intuitive shape recognition has not been determined yet. Meanwhile, there is also a fundamental problem; that is, real fingers and virtual objects do penetrate, which cannot be solved with such wearable displays. This article investigated the influence of both contact point density and penetration on the shape recognition performance. We prepared a real testing environment where the user touched the real object, and where we could simulate both the sparse contact point and the penetration. Specifically, users' fingers wore thin film coated with glass particles and they touched the urethane foams that deformed flexibly. The result of experiments showed a broad trend where the sparseness of the contact and the softness of the object influenced the exploration time required to achieve recognition. In addition, the result suggested that the larger contact density could make up for the problem of penetration. We confirmed it by conducting two different tasks: (1) exploring the object surface with the index finger and (2) grasping the object surface with the thumb and the index finger.

A Study on the Review of Repair Methods and Repair Materials for the Prevention of Fire spread of Building Exterior Materials

국내의 경우 2018년도에 시행한 가연성 외장재 설치 건축물 현황조사결과 147,559동의 건축물이 이에 해당되는 것으로 조사되었으며, 상층부 및 인접건축물로의 화재확대사례는 연간 약 3,500건, 외장재에서 시작한 화재건수는 연간 약 1,500건 이상 발생하는 등 의정부 화재, 제천스포츠센터 화재와 같은 유사한 화재발생의 위험성이 내포되어 있다. 본 연구에서는 유사한 화재 재발방지를 위해 가연성 외장재가 시공된 건축물의 보수공법에 대해 조사하고 각 각의 보수재료 성능검증을 실시하였다. 보수방법의 경우 기존의 건축물 마감재를 제거한 뒤 보수재료로 보강하는 방법과 기존 마감재를 제거하지 않고 면고르기를 실시한 뒤 보수재료를 부착하는 방법을 제안했다. 또한 드라이비트 및 보수재료로서 방화석고보드, 미네랄 울, 경질우레탄 폼, 세라믹보드, ALC 패널 등 6가지 재료를 대상으로 콘 칼로리미터 시험을 실시하고 해당 재료들에 대한 기초 연소 성능을 조사하였다.In Korea, the results of a field survey on the construction of flammable exterior materials implemented in 2018 revealed that 14 7,559 buildings belong to this category. It was found that the fire spreading cases in upper and adjacent constructions are about 3,500 per year, the fires of starting in flammable exterior material are about 1,500 per year. In this study, we investigated the repair method of buildings constructed by flammable exterior material and conducted performance verification of each repair materials for prevention of similar fire. In the case of the repair method, a method of reinforcing with a repair material after removing the existing building finishing material and a method of attaching the repair material after performing the face finishing are proposed. In addition, we conducted cone calorimeter tests of 6 materials such as fireproof gypsum board, mineral wool, hard urethane foam, cera mic board and ALC panel as dryvit and repairing materials, and investigated basic combustion performance of that materials.

Study on the Characteristics of Conduction Heat Transfer According to the Heating Temperature of a Composite Wall in a Light-weight Partition

본 논문은 실내 공간구획에 사용되는 경량칸막이 복합벽체의 가열온도에 따른 이면부로의 전도 열전달 특성에 관한 연구이다. 경량칸막이 벽체로 일반적으로 사용되고 있는 복합재료로 구성된 스터드 칸막이, SGP 칸막이, 샌드위치 패널, 우레탄폼 패널, 그라스울 패널을 실험시료로 선정하고, 200 ℃, 300 ℃, 400 ℃, 500 ℃의 가열온도를 하단부 표면에 1800 s 동안 인가하여 상단부 표면인 이면부로의 전도 열전달 특성을 분석하였다. 실험결과 가열온도가 최대 500 ℃로 인가됨에 따라 최대 이면온도는 스터드 칸막이 51.6 ℃, SGP 칸막이 63.6 ℃, 샌드위치 패널 317.2 ℃, 우레탄폼 패널 124.9 ℃, 그라스울 패널 42.2 ℃로 측정되었다. 500 ℃에서의 최대 전도 열전달율은 스터드 칸막이 17.16 W, SGP 칸막이 18.39 W, 샌드위치 패널 136.65 W, 우레탄폼 패널 14.34 W, 그라스울 패널 5.57 W로 측정되었다.The paper reports the characteristics of conduction heat transfer to the backside part according to the heating temperature of a composite wall in a lightweight partition used for indoor space compartments. Stud partitions, SGP partitions, sandwich panels, urethane foam panels, and glass wool panels. which are generally used as light-weight partition walls, were selected as experiment samples, and the characteristics of conduction heat transfer to the backside part as the top surface were analyzed by applying heating temperatures of 200 ℃, 300 ℃, 400 ℃, and 500 ℃ to the bottom surface for 1800 s. According to the experimental results, the maximum backside temperatures at the maximum heating temperature of 500 ℃ was 51.6 ℃, 63.6 ℃, 317.2 ℃,124.9 ℃, and 42.2 ℃ for the stud partition, SGP partition, sandwich panel, urethane foam panel, and glass wool panel, respectively. The maximum conduction heat- transfer rates at 500 ℃ were 17.16 W, 18.39 W, 136.65 W, 14.34 W, and 5.57 W for the stud partition, SGP partition, sandwich panel, urethane foam, and glass wool panel, respectively.

Effect of cellular structure on deformation mechanism for urethane foam

Effect of cellular structure on deformation mechanism for urethane foam

Investigation of effects of urethane foam mattress hardness on skin and soft tissue deformation in the prone position using magnetic resonance imaging

AimIn operating rooms, the occurrence of pressure ulcers caused by being in the prone position is the highest among that of pressure ulcers caused by being in other surgical positions. Thus, we investigated effects of hardness and shape of urethane foam mattresses for preventing pressure ulcers during surgery performed with patients in the prone position. We aimed to elucidate how mattresses of variable hardness and shapes affect compression and displacement of the skin and soft tissues with external force in the prone position. Material and methodsWe assessed effects of two shapes [rectangular cube (RC) and trapezoid cube (TC)] and four degrees of hardness (50, 87.5, 175, and 262.5 N) in each shape. We performed magnetic resonance imaging (MRI) of the iliac crests with external force while participants reclined in the prone position on eight different mattresses. ResultsCompression of the skin and soft tissue was significantly higher with 87.5-, 175-, and 262.5-N mattresses than that with 50-N mattresses. Skin and soft tissue displacement was higher with TC mattress than that with RC mattress, and the extent of skin surface and internal soft tissue displacement was different. ConclusionsCompression of the skin and soft tissue depends on mattress hardness; however, a threshold value (175 N) for hardness exists, above which no further changes in the parameters were observed. Skin and soft tissue displacement does not depend on mattress hardness, but rather on its shape. Furthermore, mattress inclination increases skin surface displacement.

Experimental Direct Measurement of Clot-Capturing Ability of Stent Retrievers

Stent retrievers (SRs) can be used to perform mechanical thrombectomy for the treatment of acute major arterial occlusion. Recanalization is faster, and outcomes are better with treatment involving these devices than with internal treatment. Although several SRs are available, their clot-capturing abilities are unclear. Therefore in the present study, we numerically evaluated the clot-capturing abilities of SRs in an experimental vascular model. A sham clot (urethane foam) was fixed with sutures at the middle of a vascular model (polyvinyl chloride tube). One end of the tube was connected to a measuring instrument. From the other end, an SR was inserted and deployed over the sham clot. The delivery wire of the stent was then withdrawn at a constant velocity using an automatic withdrawal machine. The maximum frictional force before the stent left the clot was measured. Five stents (Trevo ProVue [2 sizes], Revive, and Solitaire [2 sizes]) and three stent-deployment techniques (standard, push-and-fluff, and wire-push techniques) were evaluated. The clot-capturing ability (maximum withdrawing force [N: newton]) was greater for large-diameter stents than for small-diameter stents (mean 0.39 ± 0.11 vs. 0.56 ± 0.18). For Trevo and Revive, the clot-capturing ability was highest with the push and fluff technique (mean 0.43 ± 0.05). For Solitaire, the ability was the highest with the simple wire-push technique (mean 0.705 ± 0.16). We successfully numerically evaluated the clot-capturing abilities of SRs. The clot-capturing ability differed among SRs and among stent-deployment techniques.

Using nano-attapulgite clay compounded hydrophilic urethane foams (AT/HUFs) as biofilm support enhances oil-refinery wastewater treatment in a biofilm membrane bioreactor

Petroleum refinery wastewater (PRW) treatments based on biofilm membrane bioreactor (BF-MBR) technology is an ideal approach and biofilm supporting material is a critical factor. In this study, BF-MBR with nano-attapulgite clay compounded hydrophilic urethane foams (AT/HUFs) as a biofilm support was used to treat PRW with a hydraulic retention time of 5 h. The removal rate of 500 mg/L chemical oxygen demand (COD), 15 mg/L NH4+ and 180 NTU of turbidity were 99.73%, 97.48% and 99.99%, which were 23%, 20%, and 6% higher than in the control bioreactor, respectively. These results were comparatively higher than that observed for the sequencing batch reactor (SBR). The death rate of the Spirodela polyrrhiza (L.) irrigated with BF-MBR-treated water was 4.44%, which was similar to that of the plants irrigated with tap water (3.33%) and SBR-treated water (5.56%), but significantly lower than that irrigated with raw water (84.44%). The counts demonstrated by qPCR for total bacteria, denitrifiers, nitrite oxidizing bacteria, ammonia oxidizing bacteria, and ammonia-oxidizing archaea were also higher in BF-MBR than those obtained by SBR. Moreover, the results of 16 s rRNA sequencing have demonstrated that the wastewater remediation microbes were enriched in AT/HUFs, e.g., Acidovorax can degrade polycyclic aromatic hydrocarbons, and Sulfuritalea is an efficient nitrite degrader. In summary, BF-MBR using AT/HUF as a biofilm support improves microbiome of the actived sludge and is reliable for oil-refinery wastewater treatment.

Evaluation of chemical-specific IgG antibodies in male workers from a urethane foam factory

BackgroundPlastic resins are complex chemicals that contain toluene diisocyanate (TDI) and/or trimellitic anhydride (TMA), which cause occupational allergies (OA), including respiratory allergies. Serum IgGs against TDI and TMA have been suggested as potential markers of the exposure status and as exploring cause of OA. Although TDI-specific IgG has been examined for suspected OA, TMA-specific IgG is not commonly evaluated in a urethane foam factory. This study therefore investigated both TDI- and TMA-specific IgGs in suspected OA patients and to evaluate the usefulness of the measurement of multiple chemical-specific IgG measurement for practical monitoring.MethodsBlood samples were collected from two male workers who developed respiratory allergies supposedly caused by occupational exposure to TDI and/or TMA for the presence of TDI- and TMA-specific IgGs. In addition, blood samples from 75 male workers from a urethane foam factory, along with 87 male control subjects, were collected in 2014 and tested for the same IgGs in 2014. The presence and levels of TDI- and TMA-specific serum IgGs were measured using dot blot assays.ResultsWe found that controls had mean concentrations of TDI- and TMA-specific IgGs of 0.98 and 2.10 μg/mL, respectively. In the two workers with respiratory allergies, the TDI-specific IgG concentrations were 15.6 and 9.51 μg/mL, and TMA-specific IgG concentrations were 4.56 and 14.4 μg/mL, which are clearly higher than those in controls. Mean concentrations of TDI- and TMA-specific IgGs in the factory workers were 1.89 and 2.41 μg/mL, respectively, and are significantly higher than those of the controls (P < 0.001 and P < 0.026 for TDI- and TMA-specific IgGs, respectively).ConclusionThe workers suspected of OA showed an evidently high level of TDI- and TMA-specific IgG, and these levels in workers at the urethane foam factory were also significantly higher than those in controls. In conclusion, the measurement of TDI- and TMA-specific IgG among workers using plastic resins is helpful to monitor their exposure status.

Directionally Antagonistic Graphene Oxide-Polyurethane Hybrid Aerogel as a Sound Absorber.

Innovative sound absorbers, the design of which is based on carbon nanotubes and graphene derivatives, could be used to make more efficient sound absorbing materials because of their excellent intrinsic mechanical and chemical properties. However, controlling the directional alignments of low-dimensional carbon nanomaterials, such as restacking, alignment, and dispersion, has been a challenging problem when developing sound absorbing forms. Herein, we present the directionally antagonistic graphene oxide-polyurethane hybrid aerogel we developed as a sound absorber, the physical properties of which differ according to the alignment of the microscopic graphene oxide sheets. This porous graphene sound absorber has a microporous hierarchical cellular structure with adjustable stiffness and improved sound absorption performance, thereby overcoming the restrictions of both geometric and function-orientated functions. Furthermore, by controlling the inner cell size and aligned structure of graphene oxide layers in this study, we achieved remarkable improvement of the sound absorption performance at low frequency. This improvement is attributed to multiple scattering of incident and reflection waves on the aligned porous surfaces, and air-viscous resistance damping inside interconnected structures between the urethane foam and the graphene oxide network. Two anisotropic sound absorbers based on the directionally antagonistic graphene oxide-polyurethane hybrid aerogels were fabricated. They show remarkable differences owing to the opposite alignment of graphene oxide layers inside the polyurethane foam and are expected to be appropriate for the engineering design of sound absorbers in consideration of the wave direction.

Development of Semi-Incombustible Composite Insulating Board Containing Pine Leaf Powder and Vermiculite

본 연구는 송엽분과 질석을 주 원료로 하여 건축용 및 선박용으로 적용될 수 있는 준불연 단열복합보드를 개발하고 불연성능, 준불연성능, 보드 전체의 열관류율을 평가하였다. 가연성 물질인 송엽분과 유연바인더의 비율에 따라 보드의 화재저항성능이 결정되었으며, 가연물질이 불포함된 보드의 경우 불연성능을 확보하였다. 송엽분 6%를 첨가한 보드는 준불연 성능을 확보할 수 있었으며, 그 이상의 송엽분이 포함되거나 가연성의 바인더가 첨가될 경우 준불연 성능을 확보할 수 없는 것으로 나타났다. 또한, 글래스울과 폴리우레탄 뿜칠을 단열층으로 하고 개발된 불연/준불연 보드를 이용하여 1차 마감한 복합벽체는 200 mm 두께에서 국내법규 상의 건축물 단열기준을 상회하여 만족하는 것으로 나타났다.A Semi-Incombustible Composite Insulation Board (SICIB) that can be applied to building construction and ships was developed. The SICIBs comprised of pine leaf powder, vermiculite. The incombustibility, semi-incombustibility, and U-factor of the developed SICIBs were measured. The incombustibility of the each SICIB was determined by the proportion of combustible flexible binder and pine leaf powder. SICIB satisfied the incombustibility test without a combustible flexible binder and pine leaf powder. In addition, SICIB with 6% of pine leaf ensured its semi-incombustible performance. A combustible flexible binder or pine leaf powder over 6% failed the fire-resistant performance of SICIB. In addition, SICIBs with incombustible/semi-incombustible finishing and a 200 mm insulating layer (glass wool and sprayed poly urethane foam) met the U-factor of an external wall for buildings described in the Korean building code.

Analysis of the Working Conditions of Fire Protection Systems in the Goyang Bus Terminal Building Fire

화재조사 결과를 토대로 고양종합터미널 건물 화재 시 소방시설 작동 실태를 분석하였다. 분석결과를 요약하면 다음과 같다. 첫째, 천장 우레탄폼에 불이 붙은 직후에 옥내소화전을 이용하여 진화할 수 있음에도 시도하지 않았다. 둘째, 지하1층 대수선공사 공간은 스프링클러 알람밸브를 잠가놓아 작동하지 않았지만, 지하2층과 지상1층, 지상2층, 지상3층은 스프링클러가 작동하여 지하1층 대수선공사 공간 이외의 층으로의 화재확산을 저지하였다. 셋째, 피난유도등은 정상 작동하였지만, 터미널 2층 대합실에서 승차장 쪽으로 통하는 출구(비상구)에 피난구유도등이 설치되어 있지 않아 터미널 2층에서 다수의 사상자가 발생하게 하는데 영향을 미쳤다. 넷째, 화재수신기에서 제연설비 배기 팬 제어반에 전기신호를 보냈지만 배기 팬의 제어반에서 수동으로 취급하여 터미널 2층 제연설비 배기 팬이 작동하지 않았다.This study analyzed the working conditions of the fire protection system in the Goyang Bus Terminal fire based on the fire investigation results. The results were as follows. First, extinguishing using an indoor fire hydrant was not attempted immediately after the fire burned the ceiling urethane foam. Second, a sprinkler alarm valve was turn off and did not work in the repair work space of the 1st basement. On the other hand, the sprinklers in the 2nd basement, 1st floor, 2nd floor, and 3rd floor worked and prevented the fire from moving to stories other than the 1st basement. Third, although an exit light worked normally, it was not installed in the exit from the waiting room in the 2nd floor to the bus stop. This resulted in many casualties. Fourth, although a fire receiver sent an electrical signal to the fan controller of the smoke control system, it was treated manually in the fan controller and the fan in the 2nd floor did not work.

Power performance analysis of a transparent DSSC BIPV window based on 2 year measurement data in a full-scale mock-up

Among transparent solar cells or modules, the DSSC (Dye-sensitized solar cell) has a relatively low production cost compared to silicon-based solar cells and provides a range of colors for building design. On the other hand, its commercialization has been limited by the low power generation efficiency and durability. Few studies have examined the power generation performance of a full scale DSSC module applied to actual buildings. In this study, a long-term performance test was conducted on vertical and inclined DSSC BIPV (Building Integrated Photovoltaic) windows applied to a full-scale mock-up facility to verify the power performance and power characteristics of transparent DSSC BIPV glazing under actual conditions over a 2 year period.The DSSC module was fabricated by the serial connection of nine 2.26Wp transparent DSSC sub-modules. The multi-layered DSSC BIPV glazing, which was composed of a “DSSC module (9mm)” + “air space (12 mm)” + “clear glass (5mm)” was joined to the curtain wall frame of the test cell facility.The unit size of the DSSC BIPV glazing was 0.975 m (W) × 0.965 m (H) and its maximum capacity was 20.34Wp. The size of the test cell facility was 3 m (W) × 3 m (H) × 9 m (D). The building is a container type insulated with 100 mm urethane foam. Four and two DSSC BIPV windows were installed on the vertical south wall and on the 30° sloped roof, respectively. Through the monitoring system, the power performance data of each DSSC BIPV windows and meteorological data were analyzed over a two year period (from 1st Jan. 2015 to 31st Dec. 2016).The 2 year data showed that the average daily power yield for each month of the vertical DSSC BIPV window ranged from 1.75 to 3.93 kWh/kWp·day (average 2.53 kWh/kWp·day), whereas that of the 30° sloped DSSC BIPV window ranged from 2.16 to 5.34 kWh/kWp·day (average 3.60 kWh/kWp·day).The operating power efficiency of the vertical DSSC BIPV window ranged from 2.65 to 4.14% with an average of 3.40%, whereas that of the sloped DSSC BIPV window was in the range of 2.64–3.63% with a mean of 3.01%. The power generation efficiency of the vertical plane BIPV window was higher than the sloped BIPV window. In contrast to the average daily power yield, the power efficiency of the vertical window was higher than that of the sloped window, which may be due to the higher efficiency of the DSSCs under overcast conditions. This is consistent with the power performance of the DSSC BIPV windows according to the sky conditions, which showed an increase in power efficiency with increasing cloud cover or decreasing solar intensity.

Low-velocity impact response of wood-strand sandwich panels and their components

AbstractProfiled hollow core sandwich panels (SPs) and their components (outer layers and core) were manufactured with ponderosa and lodgepole pine wood strands to determine the effects of low-velocity impact forces and to observe their energy absorption (EA) capacities and failure modes. An instrumented drop weight impact system was applied and the tests were performed by releasing the impact head from 500 mm for all the specimens while the impactors (IMPs) were equipped with hemispherical and flat head cylindrical heads. SPs with cavities filled with a rigid foam insulation material (SPfoam) were also tested to understand the change in EA behavior and failure mode. Failure modes induced by both IMPs to SPs were found to be splitting, perforating, penetrating, core crushing and debonding between the core and the outer layers. SPfoams absorbed 26% more energy than unfilled SPs. SPfoams with urethane foam suffer less severe failure modes than SPs. SPs in a ridge-loading configuration absorbed more impact energy than those in a valley-loading configuration, especially when impacted by a hemispherical IMP. Based on the results, it is evident that sandwich structure is more efficient than a solid panel concerning impact energy absorption, primarily due to a larger elastic section modulus of the core’s corrugated geometry.

Design and Evaluation of Glass/epoxy Composite Blade and Composite Tower Applied to Wind Turbine

In the study, the analysis and manufacturing of small class wind turbine blade was performed. In the structural design, firstly the loading conditions are defined through the load case analysis. The proposed structural configuration of blade has a sandwich type composite structure with the E-glass/Epoxy face sheets and the Urethane foam core for lightness, structural stability, low manufacturing cost and easy manufacturing process. And also, this work proposes a design procedure and results of tower for the small scale wind turbine systems. Structural analysis of blade including load cases, stress, deformation, buckling, vibration and fatigue life was performed using the finite element method, the load spectrum analysis and the Miner rule. Moreover, investigation on structural safety of tower was verified through structural analysis by FEM. The manufacturing of blade and tower was performed based on structural design. In order to investigate the designed structure, the structural tests were conducted and its results were compared with the calculated results. It is confirmed that the final proposed blade and tower meet the design requirements.