Auswahl der wissenschaftlichen Literatur zum Thema „WVP“

Water vapour permeability (WVP) is a key parameter for the sustainable thermal conditioning of buildings. The study of the WVP in concrete with supplementary cementitious materials (SCMs) allows for the design of structures with improved durability and sustainability. To our knowledge, there is insufficient experimental data in the literature regarding the WVP of concrete with SCMs. WVP tests were made on concrete mixes containing ground granulated blast-furnace slag (GGBFS) and limestone powder (LP) as a partial replacement for ordinary Portland cement, and of concrete mixes containing pozzolanic cement (NP). Results from three moisture gradients show that GGBFS induces the greatest reduction in WVP, followed by the NP. LP shows a diluting effect of the binder, which could be compensated by GGBFS in the ternary blend. From the comparison between the WVP and the capillary sorption rate, the influence of the SCMs on the connectivity of the smallest pores is assessed.

PurposeUnlike other materials, textiles associate with aesthetic and mechanical properties such as flexibility and removability that allow them to be deployed or folded as required and which make them good candidates for clothing and furnishing but also, eventually, for other applications such as building. Actually, the clothing should ensure appropriate heat and mass transfers between the human body and its environment in order to maintain the thermo-physiological comfort. For that, it is important to determine water vapor permeability (WVP) of textile. Several normalized procedures with variants depending on the nature of the tested material exist to measure the WVP. One of the methods used is the “dish method” described by the British Standard (BS 7209). The purpose of this paper is to determine the influence of the test parameters on the WVP measurements.Design/methodology/approachConsequently, WVP of different textiles was measured while varying several parameters like: nature of fabrics, air layer thickness, vapor pressure gradient and air velocity.FindingsA decrease in the WVP values was observed with an increase in the air layer thickness and the number of textile layers. On the other side, an increase in the water pressure gradient induces an increase in the WVP value. Finally, it was also observed that air velocity has an impact on the WVP measurements.Originality/valueIn addition to intrinsic properties of fabrics, i.e., nature of fiber, woven structure, the influence of the several extrinsic properties, i.e., the influence of the air layer thickness, the number of textile layers, the vapor pressure gradient and the air velocity, on the WVP were investigated. Some researchers have already investigated the impact of these parameters on the WVP measurement separately. However, this study presents a difference from other studies that it takes into account the influence of the both intrinsic and extrinsic properties on WVP. In addition to these, this work combine several extrinsic properties which are presented separately during other studies. The first time, in this study the influence of the air velocity on WVP was investigated. Results on both hydrophilic and hydrophobic fabrics showed a great variation in the results when varying the location of the cups inside the climatic chamber. This is the reason why future studies look at studying more deeply the effect of air velocity on the WVP properties on different types of fabrics by connecting WVP values with air velocity values. It is also planned to make tests with the rotation device and by fixing the value of the temperature and RH. The objective will be to obtain reliable values that do not take into account the effect of air velocity.

Abstract Composite mean fields and probability distribution functions (PDFs) of rain rate, cloud type and cover, cloud-top temperature, surface wind velocity, and water vapor path (WVP) are constructed using satellite observations of midlatitude cyclones from four oceanic regions (i.e., the North Pacific, South Pacific, North Atlantic, and South Atlantic). Reanalysis surface pressure fields are used to ascertain the locations of the cyclone centers, onto which the satellite fields are interpolated to give a database of ∼1500 cyclones from a two-year period (2003–04). Cyclones are categorized by their strength, defined here using surface wind speed, and by their WVP, and it is found that these two measures can explain a considerable amount of the intercyclone variability of other key variables. Composite cyclones from each of the four ocean basins exhibit similar spatial structure for a given strength and WVP. A set of nine composites is constructed from the database using three strength and three WVP ranges and is used to demonstrate that the mean column relative humidity of these systems varies only slightly (0.58–0.62) for a doubling in WVP (or equivalently a 7-K rise in sea surface temperature) and a 50% increase in cyclone strength. However, cyclone-mean rain rate increases markedly with both cyclone strength and WVP, behavior that is explained with a simple warm conveyor belt model. Systemwide high cloud fraction (tops above 440 hPa) increases from 0.23 to 0.31 as cyclone strength increases by 50%, but does not vary systematically with WVP. It is suggested that the composite fields constitute useful diagnostics for evaluating the behavior of large-scale numerical models, and may provide insight into how precipitation and clouds in midlatitude cyclones respond under a changed climate.

The goal of this study was to investigate the effect of differences in water vapor permeability (WVP) of outdoor jackets on moisture management, subjective perceptions and physiological parameters under conditions typically encountered in outdoor sports. Four outdoor jackets differing only in their WVP were compared in a repeated measures study. A total of 19 subjects (nine females) were tested in a climatic chamber at 10℃ and 40% relative humidity. The protocol consisted of 15 min of rest, 50 min of treadmill running at 60% of the individual maximal running velocity, and 15 min of passive recovery. We found that jackets featuring greater WVP helped to reduce relative humidity underneath the jacket, resulting in less sweat residue in the clothing system and drier skin during exercise and rest. Subjects were also able to perceive the differences in the microclimate and reported feeling more comfortable and drier in the more permeable jackets. However, WVP did not have a significant effect on oxygen consumption, heart rate, tympanic temperature, overall loss of subjects’ body mass or on perceived exertion. It can be concluded that outdoor jackets with higher WVP benefit moisture management during submaximal exercise in cool temperatures by reducing relative humidity in the clothing system mostly during rest periods. This effect leads to a drier skin which favors perceived comfort and might reduce the after-chill effect. However, WVP of outdoor jackets neither significantly affects physiological responses nor perceived exertion during submaximal exercise in a cool environment.

Production of Polylactic acid (PLA)/Polycaprolactone (PCL) bionanocomposite films with various ratios was done by adding nanocrystalline celullose (NCC) from oil palm empty fruit bunches (OPEFB) as a filler. The aim of the research was to find out the effect of PLA/PCL ratio on film thickness, transparency of bionanocomposite films and water vapor permeability or WVP of the film bionanocomposite with addition of the 3% NCC. The PLA/PCL ratio are 1.0/0.0; 0.8/0.2; 0.6/0.4; 0.5/0.5; 0.4/0.6; 0.2/0.8; and 0.0/1.0, prepared with solvent casting method. Characterization of PLA/PCL bionanocomposites film performed was thickness, transparency test and water vapor permeability (WVP) test. The thickness of bionanocomposites film produced were around are about 0.036-0.053 mm, results show that the lower PLA/PCL ratio the thicker film obtained. The highest value of film transparency was obtained at a ratio of 1.0 / 0.0 (81.4% at a wavelength of 550 nm), the smaller the PLA / PCL ratio, the lower the value of transparency. The WVP value of PLA/PCL bionanocomposite films gives a lower value than the WVP value of pure PLA film and pure PCL film. The best WVP was obtained at a PLA/PCL ratio of 0.8/0.2 which was 1.49x10-16kg.m/(m2.s.Pa).

The aim of the present work was to investigate the moisture sensitivity of soy protein isolate (SPI) films blending with poly (vinyl alcohol) (PVA) plasticized by glycerol. Water vapor permeability (WVP) was measured based on the contents of PVA and glycerol in films. WVP values of various SPI/PVA films with/without glycerol were in the range of 8.25 and 10.9 g mm/m2 h kPa. The results showed that WVP values decreased with the increasing content of PVA. Moreover, XRD tests confirmed that the glycerol would insert into the macromolecular blending structure and destroy the crystalline of blends, and the crosslinkage between glycerol molecules and SPI reduced the interstitial spaces in protein matrix, thus allowing for decreasing diffusion rate of water molecules through the films.

In this paper, gelatin-based films were prepared by mixing gelatin with glycerol, and microbial transglutaminase (mTG) which was used as cross linking agent. The result of SEM confirmed that a dense network structure was formed after mTG treatment comparing to the native. The effect of mTG on water barrier property of films was investigated by measuring the water vapor permeability (WVP). The results showed that the concentration of gelatin has a significant influence on the water barrier property of gelatin-based film which was treated with mTG. The WVP value of the films decreased sharply after enzymatic cross-linking when gelatin concentration increased to 8%, while no evident change of the WVP can be found when the gelatin concentrations was lower than 8%.

The Vitrification Test Rig (VTR) is a full scale non-active waste vitrification plant (WVP), that replicates the lines used for immobilising highly active reprocessing waste at Sellafield in the UK. In the high level waste (HLW) vitrification process, liquid HLW is dried in a rotating tube furnace then mixed with an alkali borosilicate glass frit. This mixture is heated to form a homogeneous product glass that is poured, cooled and stored in steel canisters. The primary function of the VTR is to trial and develop methods to increase the efficiency of high level waste processing at the active WVP. Efficiency gains are mainly achieved by increasing the rate at which the immobilised product is created and by increasing the ratio of HLW to glass frit in the product. The VTR has also been used to investigate the chemistry of various process additions and conditions, the effects of potential fault scenarios, and the processing of dilute waste streams that will be received by WVP in the future. All of these areas have the potential to improve processing efficiency through the optimisation of process conditions and the minimisation of unplanned plant outages. This paper discusses several VTR campaigns that have led to overall improvements of WVP operation.

The present study was to investigate the film forming properties of tilapia skin gelatin as affected by the addition of 2%, 5% Arabic gum or pectin (g/g gelatin), as well as 1%, 2% glutaraldehyde (GTA) (g/g gelatin) in an attempt to improve gelatin film properties. Tensile strength (TS) and transparency of gelatin film were improved 36.6% and 30.3% by the addition of Arabic gum, respectively, while the water vapor permeability (WVP) was not affected. The addition of pectin had less effect on the film tensile strength and transparency, but led to 41.7% of increase in WVP. Tensile strength and WVP of gelatin-arabic gum composite film cross-linked with 2% GTA were better than those of 1% GTA cross-linked composite film, though the extensibility and transparency were slightly weak. The FTIR spectra of gelatin films showed that both Arabic gum and pectin formed cross-linkages with gelatin protein molecules, while GTA facilitated the formation of intermolecular bonds, resulting in more stable films.

Films were prepared from a renewable and biodegradable forest biorefinery product, spruceO-acetyl-galactoglucomannans (GGMs), crosslinked with glyoxal. For the first time, cohesive and self-standing films were obtained from GGM without the addition of polyol plasticizer. In addition, glyoxal-crosslinked films were prepared using sorbitol at 10, 20, 30, and 40% (wt.-% of GGM). Glyoxal clearly strengthened the GGM matrix, as detected by tensile testing and dynamic mechanical analysis. The elongation at break of films slightly increased, and Young's modulus decreased with increasing sorbitol content. Interestingly, the tensile strength of films was constant with the increased plasticizer content. The effect of sorbitol on water sorption and water vapor permeability (WVP) depended on relative humidity (RH). At low RH, the addition of sorbitol significantly decreased the WVP of films. The glyoxal-crosslinked GGM films containing 20% sorbitol exhibited the lowest oxygen permeability (OP) and WVP of the studied films and showed satisfactory mechanical performance.

Executive summary Today, packaging has gained a significant role in the food industry as well as other industries. Paper substrates that have been coated in some ways are typically used to make packaging. The amount and type of pigment used in the formulation determine whether this coating is a pigment coating or a barrier coating. Critical pigment volume concentration (CPVC) is the optimum spot when the pigments are packed as densely as possible, and the binder fills the air gaps. When the amount of pigment in a coating is less than CPVC, a barrier coating is formed, although when the amount of pigment in the coating is greater than CPVC, a pigment coating is formed. Pigment coating adds optical properties to a package, such as improved printability. And chemical protection is primarily provided for water, water vapour, fats, and gases in the case of the barrier coating. Chemical protection against these substances means, for food packaging, that the shelf life of the product will be extended, among other things. The role of packaging in society is expected to grow as barrier coatings on packaging continue to improve. The use of nanoclay in barrier coatings is investigated in this laboratory study. Two latexes are tested with nanoclay, with latex chosen based on its glass transition temperature (Tg). The hypothesis was that a latex with a higher Tg would have more properties like brittleness and orderly structure in its amorphous structure than the other latex. Latex with a lower Tg, on the other hand, would have more elasticity, be more ductile, and have a lower degree of ordered structure in its amorphous structure. Latex with a higher Tg was referred to as Hard latex and was composed of Styrene-butadiene, while latex with a lower Tg was referred to as Soft latex and was composed of Polyolefin dispersion, although it is unorthodox to call it latex. Previous research has found that the addition of Bentonite nanoclay can improve the mechanical and barrier properties of barrier coatings. Bentonite was therefore chosen as the nanoclay for this study due to having a higher aspect ratio, is flaky and can improve desired properties. The coating was applied as a dispersion coating using a lab-scale rod coater. The substrate for this study was BillerudKorsnäs FibreForm with a grammage of 150 g/m2.In order to find the optimum rod for the coating, three different rods were tested during screening test 1. The rods tested were based on the desired coating weight and thickness, a red rod with a wet film thickness of 12 μm was chosen. The nanoclay content of the latex formulation was investigated to determine the optimal level for improved barrier properties. In screening test 2, the concentrations examined were 2/4/8 w/w% nanoclay in each latex, and 0 w/w% to compare the difference with Hard/Soft latex to see if there are any benefits of nanoclay. For both latexes, the addition of 2/4 w/w% nanoclay resulted in more pinholes as well as a poor water vapour transmission rate and permeability. The results of screening test 2 showed that adding 8 w/w% nanoclay to both latexes improved the water vapour transmission rate, water vapour permeability, and pinholes test when compared to the other concentrations of nanoclay. In the water vapour transmission rate and pinholes test, however, 0 percent nanoclay performed similarly 8 w/w% for each latex formulation. The selected formulation for further study was 8 w/w% nanoclay with Hard/Soft latex.  Water vapour was the most important barrier property to investigate since barrier coatings were intended for food packaging. For the intended food packaging, it was sought that the barrier could be stretched with 3.8/6.7/10.4%-stretch and then characterized by water vapour transmission rate to be able to see the differences before and after stretching. Stretching with tensile tester were performed on a barrier coated FibreForm, first in the machine direction (MD), then in cross-direction (CD). Hydroforming with shaped bubbles was used for the second method of stretching with various bubbles. Stretching in MD + CD, and hydroforming bubbles were done according to the desired %-stretching. Characterization of the coating was done by water vapour transmission rate (WVTR) for all coatings, pinholes test for hydroformed coatings, water vapour permeability (WVP) and scanning electron microscopy (SEM) on tensile-stretched coatings. The performance of Soft latex with an 8 w/w% formulation stretched in MD then CD and characterized by water vapour transmission rate was significantly unchanged despite stretching up to 10.4%. This is thought to be because nanoclay, as the literature suggests, has created a better barrier against water vapour. The mean WVTR of 10.4%-stretching in MD then CD was 5.5 g/m2/day, compared to 5.5 g/m2/day for the unstretched barrier.  SEM images of both stretched and non-stretched coatings show that the dispersion of nanoclay is poor, as there are islands of polymer and nanoclay bulk. The poor dispersion of nanoclay in the matrix was due to the lack of polar groups in the backbone of Soft latex (Polyolefin) and also being hydrophobic, as opposed to Bentonite, which is hydrophilic. Despite poor nanoclay dispersion and a stretch of 10.4% in MD + CD, resulting in reduced barrier thickness, WVP improved from 289 g* /m2/day (pre-stress) to 191 g* /m2/day (10.4%-stretch), giving the impression of some reorientation of nanoclay in the polymer matrix. A crack was also visible in SEM images, near the boundary layer between the barrier and the substrate, on an unstretched coating, which is thought to be caused by the difference in the boundary layer and adhesive forces, that has occurred during drying. Cracks are not visible on the stretched barriers, even though it was expected. With increased stretching of hydroforming substrates coated with Soft latex formulation, the performance of water vapour transmission rate was significantly worse. The reason for this is thought to be that the barrier was damaged during hydroforming due to friction during pressing and shaping, as the hydroforming was done on the barrier side. The pinhole test revealed clearly degraded performance with a large number of pinholes. This could indicate that the barrier has been stretched beyond its capacity or has been damaged. There was no correlation found between stretching in tensile tester and hydroforming.  Hard latex with an 8 w/w% formulation stretched in MD then CD and characterized by water vapour transmission rate could be stated to have significantly improved performance despite stretching up to 10.4%. The mean-WVTR of 10.4%-stretching in MD then CD was 11.3 g/m2/day, compared to 16.4 g/m2/day for the unstretched barrier. According to SEM images, the reason for this is that nanoclay was very well dispersed in the matrix and that there has seemingly been a slight reorientation of nanoclay with increased stretch. Furthermore, SEM images show that the thickness was reduced, yet despite this, mean-WVP improved from 1094 g* /m2/day (pre-stress) to 419 g* /m2/day (10.4%-stretch), indicating reorientation of nanoclay and thus improved stretchability.These SEM images show cracks at the boundary layer between the barrier and the substrate for both unstretched and 10.4%-stretched barriers in the Hard latex formulation. The cracks are seemingly stopped by nanoclay in the matrix, according to the stress concentration effect, where the crack moves around nanoclay and not through nanoclay. Hydroforming of barrier coated Hard latex formulation showed a deterioration of water vapour transmission rate with increased stretching. The mean WVTR of hydroforming with 10.4%-stretching was 30.6 g/m2/day. It is not thought that pressing during hydroforming damaged the Hard latex barrier as much, which can be confirmed by the pinholes test. Pinholes test demonstrated good performance and comparable to an unstretched barrier. Because comparisons between the different polymers were impractical, it was not possible to state if the glass transition temperature was important for the improvement seen by stretching in the tensile tester. But it can be argued that Hard latex has a more structured and rigid structure, allowing for a greater degree of reorientation. Soft latex, on the other hand, has less stiffness and thus less reorientation. The result of this study is that when stretching is done in both tensile testing and hydroforming, 8 w/w% nanoclay (bentonite) with Hard latex (styrene-butadiene) can be used advantageously in FibreForm packaging if stretchability is desired while maintaining barrier properties against water vapor.
Sammanfattning Idag har förpackningar fått en betydande roll i matindustrin såväl som andra industrier. Vid bestrykning på förpackningar och papperssubstrat så är det vanligt med pigment- eller barriärbestrykning. Vid pigmentbestrykning så tillförs optiska egenskaper till förpackningen, såsom exempelvis förbättrad tryckbarhet. Vid barriärbestrykning tillförs huvudsakligen kemisk skydd mot exempelvis vatten, vattenånga, fetter eller gaser, och innebär för matförpackningar bland annat att hållbarheten blir längre för livsmedlet. Genom fortsatt utveckling av barriärbestrykningar på förpackningar så förväntas även förpackningens roll i samhället att bli större. I denna laborativa studie undersöks möjligheterna kring töjbara barriärer på papperssubstrat, med fokus på vattenångaresistans.  De formuleringar som togs fram bestod av en latex med låg glasövergångstemperatur (Tg), kallad Soft latex med implementerad nanolera samt en latex med en Tg kallad Hard latex med implementerad nanolera. Soft latex var en Polyolefin dispersion med Tg -30°C, och Hard latex var en Styren-butadien latex med Tg = 0°C. 8 w/w% nanolera var den halt som bedömdes ge förbättringar i de mekaniska samt barriäregenskaper som eftersöktes för de båda latex. För denna studie valdes Bentonit som nanolera, på grund av dess plana samt dess fjälliga (flaky) struktur.  Töjbarheten hos de framtagna barriärformuleringarna testades med töjning i dragprov först i maskin-riktning (MD) och sedan tvär-riktning (CD) samt töjning med hydroforming, med töjning på 3,8/6,7/10,4% för respektive metod. Efter töjning av respektive metod bestämdes överföringshastigheten av vattenångpermabilitet (WVTR) genom barriären. En jämförelse gjordes mellan töjning i dragprov och hydroforming för att få en ökad förståelse kring WVTR-prestationen beroende på metod av töjning.  Soft latex visade en oförändrad vattenångaresistans efter 10,4%-töjning i dragprovaren. Detta tros bero på att nanoleran försvårar vattenångan att genomträngas trots töjning. Vid elektronmikroskop (SEM) kunde det ses att dispersionen av nanolera med Soft latex inte var bra, och därför var inte förbättringarna lika tydliga. Den sämre dispersionen av nanolera i matrisen beror på att Polyolefin saknar polära grupper i dess ryggrad (backbone) samt är väldigt hydrofobt, till skillnad från Bentonit som är hydrofilt. Trots sämre dispersion av nanolera och en töjning på 10,4% i MD + CD, så förbättrades vattenånga permeabiliteten (WVP).För hydroforming var prestationen av Soft latexformuleringen gällande WVTR dåliga, och vid Pinholes test fanns det uppenbara pinholes.  Hard latex visade en tydlig förbättring av WVTR efter 10,4%-töjning i dragprovaren, som tros bero på en omorientering av nanoleran i polymer matrisen vid töjning, vilket kan bekräftas av elektronmikroskop (SEM) där viss omorientering är synlig. Dessutom sågs en tydlig förbättring i WVP trots en lägre barriärtjocklek.För hydroforming var WVTR-värdena liknande till endast Hard latex och 0% nanolera.  Vid töjning var jämförelser beroende på de olika glasövergångstemperaturerna hos polymererna inte möjlig, och därför inte heller möjligt att konstatera ifall glasövergångstemperaturen var viktig för den förbättring som setts trots töjning i dragprovare. Men det kan hävdas att Hard latex har en mer strukturerad och stel struktur, vilket möjliggör en större grad av omorientering. Soft latex däremot, är mindre styvt och mindre ordnat, därav åstadkoms en mindre omorientering.  Resultaten av denna studie är att när stretching görs i både dragprovning och hydroformning, kan 8 w/w% nanoclay (bentonit) med Hard latex (styren-butadien) vara fördelaktig i FibreForm-förpackning om töjbarhet önskas samtidigt som barriäregenskaperna mot vattenånga bibehålls.

Problema – daug agentų technologiją nagrinėjančių straipsnių ir kitų rašto darbų, tačiau mažai sukurtų realių programų, naudojančių ją. Neaiškus agentų technologijos panaudojimas ir pritaikymas mobiliojoje komercijoje, nedidelis susidomėjimas iš verslo pusės. Neaiški padėtis agentų platformos rinkoje. Darbo tikslas – agentų technologijos panaudojimo mobiliosios komercijos kontekste analizė. Spręsti uždaviniai: - agentų platformų kokybinę ir kiekybinę analizė; - mobiliosios komercijos sistemos modelio sukūrimas; - modelio realizavimas suprogramuojant sistemą. Darbo metodai – agentų platformų kokybinė (literatūros analizė) ir kiekybinė analizė (atlikti programiniai testai), prototipo realizavimas. Išvados. Mobiliosios komercijos sistemos prototipu, sukurtu naudojant agentų technologiją, parodyta, kad pati agentų technologija yra gyvybinga ir jos atsisakyta per anksti. Sukurtas sistemos prototipas gali būti panaudotas praktikoje ir atnešti naudą.
Main problem – there is a lot of work done which studies agent technology. But taken in comparison, there is much less real software created using this technology. Not obvious use of agent technology leads to a little or even no attention from business. Furthermore, not clear situation in agent platforms market reduces it drastically. Work objective – analysis of agent technology use in mobile commerce context. Solved problems: - Qualitative and quantative analysis of agent platforms. - Creation of mobile commerce system model. - Model implementation. Conclusion. With creation of mobile commerce system prototype, which uses agent technology, it is shown that agent technology is viable and this technology should not be rejected to early. Created system prototype can be used in practise. One can benefit from using it.

Gemeinsamer Workshop von Universitaetsrechenzentrum und Professur "Rechnernetze und verteilte Systeme" der Fakultaet fuer Informatik der TU Chemnitz. Workshop-Thema: Mobilitaet Der Vortrag stellt die Software wapsh/htsh vor. Damit ist ist der Zugang zu einer Shell auf einer Unix-Maschine über einen Web- oder WAP-Browser möglich. Es wird untersucht, ob und wie diese Software für den Einsatz im URZ zur "mobile system administration" geeignet ist.

Es wird ein einfacher Berechnungsansatz für ein Baukastensystem aus Kastenprofilen verschiedener Querschnittsabmessungen erarbeitet. Diese Profile bestehen aus WVC (Wood Veneer Composites, Holzfurnierlagenverbundwerkstoffen). Der Ansatz bildet den statischen Lastfall und das Ermüdungsverhalten unter schwellende Dreipunktbiegung ab. Am Beispiel eines ausgewählten Strukturbauteils aus handelsüblichen Birkensperrholz wird der Berechnungsansatz konkretisiert und durch Versuche evaluiert. Aufbauend auf dem Kraft-Verformungsverhalten der analysierten Einzelbauteile und der kapillarporösen Struktur des Holzes wird bei dem Berechnungsansatz auf eine Analyse der Spannungen verzichtet. Stattdessen wird als Berechnungskriterium die kritische Normaldehnung in der Randfaser der Strukturbauteile genutzt. Weiterhin wird eine Methode vorgestellt um mittels niederzyklischen Ermüdungsversuchs (LCF, ca. 1e+03 Lastwechsel) den „Knickpunkt“ der Zeitfestigkeitslinie eines einstufigen Ermüdungsversuchs bei hohen Lastspielzahlen (HCF, 1e+06 bis 1e+07 Lastwechsel) für diese Strukturbauteile zu bestimmen
It was developed a simple approach for the calculation of a modular construction system for box sections (profile structures) of different cross-sectional dimensions. These profile structures consists of WVC (Wood Veneer Composites). The approach maps the static load case and the fatigue behavior under pulsating three-point bending. By using a structural component made from commercial birch plywood, the calculation approach is specified and verified. Based on the force-deformation behavior of the analyzed single components in connection with the capillary-porous structure of the wood, the calculation approach dispense on an analysis of the tensions. Instead, a criterion, which calculates the critical normal strain in the outer fibers of the structural components, is used. Furthermore, a method of a low-cycle fatigue test (LCF, abbr. 1e+03 cycles) is presented. This method detects the “knee point" of the fatigue limit line for the profiles. That point is usually determined by the use of a high-cycle fatigue tests (HCF, 1e+06 until 1e+07 cycles)

Syftet med denna studie var att ta reda på hur avkodning, stavning och motivation kan påverkas av 6 veckors träning med WIP intensivprogram. WIP är en multikomponent träning där tyngdpunkten ligger på kopplingen mellan fonem-grafem, läsflyt och läsförståelsestrategier. Omfattningen av WIP intensivprogram är 12 veckor men vi ville undersöka vilken effekt det kunde ge efter halva tiden. Studien var en form av ett kvasi-experiment då en grupp fick en särskild lästräningsmetod och en annan grupp fick en vanlig lästräning i klassrummet.   Urvalet gjordes genom att samtliga elever i årskurs 3 och 4 på forskarnas egna skolor, fick göra testet Ordkedjor. De elever som hade ett staninevärde mellan 1 - 3 på det testet fick göra ytterligare ett test Lilla Duvan. De elever som låg under den kritiska gränsen, som är 79 poäng för årskurs 3, lottades in i en interventionsgrupp eller en jämförelsegrupp.   Interventionen gjordes en- till- en, 30 min/dag, 4 dagar/vecka under 6 veckor. På grund av tidsbrist fanns bara möjlighet till att ha små grupper, 6 stycken i interventionsgruppen och 6 stycken i jämförelsegruppen. Det fanns en medvetenhet om att det var på gränsen till för ett litet urval.   Studiens empiri samlades in genom både en kvantitativ ansats, en intervention, och en kvalitativ ansats genom semistrukturerade intervjuer.   Resultatet visar på att träningen med WIP under 6 veckor ger liten effekt på elevers avkodnings- och stavningsförmåga. Eleverna i interventionsgruppen var motiverade till att lästräna med metoden. Vid intervjuerna framkom att eleverna var övervägande positivt inställda till metoden.

Thesis (M.S.)--West Virginia University, 1999.
Title from document title page. Document formatted into pages; contains v, 245 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 114-115).

Durch die Entwicklung der vorgestellten modularen Bauweise ist es möglich, Maschinengestelle aus Holzfurnierlagenverbundwerkstoff (WVC) einfach herzustellen und technisch sinnvoll einzusetzen. Die modulare Bauweise kann sowohl für statische als auch dynamische Beanspruchungen im Allge-meinen Maschinenbau angewendet werden. In einem Baukastensystem werden Maschinenteile aus WVC durch geeignete Verbindungsmittel lösbar zusammengesetzt. Damit ist es möglich, eine hohe Flexibilität in der späteren Nutzung mit einer hohen Variantenvielfalt des Aufbaus durch entsprechend verschiedene Bauteile zu kombinieren. Im Vortrag werden die verschiedenen Belastungen des Holzverbundes im Maschinenaufbau charakte-risiert und auf Probleme bei der Konstruktion eingegangen. Abschließend werden Ergebnisse zu Dau-eruntersuchungen der Verbindungstechnik und des gesamten Maschinenaufbaus vorgestellt und diskutiert
The development of the presented modular construction allows to manufacture wood veneer compos-ite (WVC) machine racks easily in a technical reasonable way. The modular construction can be used for both static and dynamic loading conditions in mechanical engineering. In the modular construction system the WVC machine components are connected detachable with adequate fasteners. This leads to high flexibility during the construction and assembly process of machine components. In the current presentation the different loading conditions of WVC profiles are characterized and the problems during construction described. Finally the results of the long term testing of the connection technique are presented and the complete machine system is discussed

In the U.K., High Level Waste from reprocessing operations is vitrified at the Sellafield Waste Vitrification Plant (WVP). A small number of the nuclides present in the waste have the potential to volatilize during vitrification. In order to prevent release of any radionuclides to the environment it is important to understand the mechanisms by which volatilization may occur and to have suitable controls in place. One element of particular concern is ruthenium, formed during the fission of nuclear fuel, which has the potential to form gaseous species such as RuO4 during the vitrification process and whose behavior must therefore be understood in order to underpin the safe operation of WVP.

This work addresses the use of several signal processing tools as a means for the monitoring and the diagnosis of assembly faults in internal combustion (i.c) engines through the cold test technology. Firstly, an approach based on the use of symmetrized dot patterns for the visual characterization of vibration signatures is proposed. This method is applied in order to obtain reliable thresholds for the pass/fail decision after the cold test. Secondly, the fault identification is discussed on the basis of the cyclostationary modeling of the signals. First of all, first-order cyclostationarity is exploited through the analysis of the Time Synchronous Average (TSA). Subsequently, second-order cyclostationarity is developed by means of the mean instantaneous power, Wigner-Ville Distribution (WVD) and Wigner-Ville Spectrum (WVS). Finally, the Continuous Wavelet Transform (CWT) is presented and compared with the Wigner Ville Distribution. In order to show the effectiveness and the limitations of the above-mentioned techniques, tests were carried out for a number of different faults. In this paper the results relative to a specific fault are shown as example.

In this study, drop test reliabilities of wafer level packages (WLP) are investigated. Failure mechanism, crack map and crack initiation location are presented. Failure rates of six groups defined by JEDEC are examined through both drop test experiment and finite element (FE) analysis with ANSYS software. Effects of component placement, PCB design, WLP structures, array size, pitch, and solder alloy are studied through drop test experiment per JESD22-B111 and finite element modeling. It is found that the primary failure mechanism of WLP drop test failures is fracture of intermetallic compound (IMC) at WLP side. During the drop test, solder joints at outer columns experience most stress and will fracture first. And the corner balls always fail first. The crack initiates at inner side of solder joint and propagates to the opposite side. When JEDEC recommended PCB is used for WLP drop test, the corner components fail first. This is different from the findings from BGA packages. It is confirmed that the dominant failure rate of corner WLP components is mainly due to the effect of mounting screws, rather than the intrinsic drop test reliability of WLP. Therefore, it is not appropriate to judge the drop test reliability of WLP with the drop test data for the corner components. Instead, middle component drop test data represent intrinsic shock resistance of WLP, and they should be used to represent the drop test performance of WLP. Drop test DOE results showed that WLP structure and material make visible difference. Non-soldermask defined (NSMD) PCB pad designs result in better drop reliability than SMD pads. With a given ball array, WLP with smaller pitch has worse drop reliability. As array size increases from 6×6 to 10×10 and 12×12, the drop test performance drops significantly. In addition, choice of solder alloy makes visible difference for WLP.

Water Jet Peening (WJP) has been widely applied to Japanese nuclear power plants since 1999 in order to mitigate stress corrosion cracking (SCC) generation on SCC susceptible material used their reactors as an approved mechanical mitigation technique against SCC [1]. Laboratory data shows that WJP has an effect to mitigate or suppress shallow crack propagation if the achieved compression depth is deeper than the crack, and that WJP has no adverse effect on pre-existing cracks on the mitigated surface, such as crack propagation during WJP treatment or acceleration effect after its treatment [2]. However, there was no field experience of applying WJP on cracked surfaces of operating reactor internals since we removed the crack(s) as the practice in Japan was to remove the crack prior to WJP implementation. When observed crack can be left as is according to its profile, it is required to perform the crack sizing periodically by Ultrasonic Testing in order to monitor its propagation. In order to apply WJP on the cracked surface, additional testing was needed to clarify that no adverse effect on UT sizing capability after WJP will be observed. The Japan Atomic Power Company (JAPC) and Hitachi-GE Nuclear Energy, Ltd. (HGNE) have performed several tests about this UT crack sizing test before and after WJP treatment and other related test before its field application.

We conduct a randomized controlled trial in Mexico City to determine willingness to pay (WTP) for SMS air quality alerts and to study the effects of air quality alerts, reminders, and a reusable N95 mask on air pollution information and avoidance behavior. At baseline, we elicit WTP for the alerts service after revealing whether the household will receive an N95 mask and participant compensation, but before revealing whether they will receive alert or reminder services. While we observe no significant impact of mask provision on WTP, higher compensation increases WTP, suggesting a possible cash-on-hand constraint. The perception of high pollution days prior to the survey is positively correlated with WTP, but the presence of actual high pollution days is not correlated with WTP. Follow-up survey data demonstrate that the alerts treatment increases reporting of receiving air pollution information via SMS, a high pollution day in the past week, and staying indoors on the most recent perceived high pollution day. However, we observe no significant effect on the ability to correctly identify which specific days had high pollution. Similarly, households that received an N95 mask are more likely to report utilizing a mask with filter in the past two weeks, but we observe no effect on using a filter mask on the specific days with high particulate matter. Although we nd that air quality alerts increased the salience of air quality and avoidance behavior, these results illustrate the difficulty that information treatments face in overcoming perceptions to effectively reduce exposure to air pollution.