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This paper is a comparative study between two African-American novels: Caucasia by Danzy Senna (1998) and Quicksand by Lenna Larsen(1928). It specifically discusses how their respective mixed-race protagonist re-appropriates the double-consciousness trope –a term originally coined by African-American scholar W. E. Du Bois to describe the existence of blacks in the United States. More specifically, I argue that Danzy Senna’s novel Caucasia transcends traditional notions of mixed-race identity found in Nella Larsen’s Quicksand. First, I establish that Helga, the mulatta protagonist of Quicksand is constructed to play the version of the double-consciousness which assumes that mixed people (black and white) in United States live with internalized racism. Next, I demonstrate that Caucasia challenges Quicksand by providing us with a mulatta protagonist who re-appropriates the notions of double-consciousness by making it instrumental to her own survival and birth-right to be mixed.

The themes of quest for racial identity in Nella Larsen’s Quicksand and the protagonist’s struggle with dual identity are the most commonly discussed topics in countless critical articles over the past twenty years. However, Larsen’s portrayal of Helga Crane’s struggle to find an identity as a woman of mixed race serves to demonstrate that her issue is mainly with how society is essentialist. The primary goal of Quicksand is to demonstrate the fluidity of identity. With the challenges that the protagonist faces in the story, Larsen vividly demonstrated that identity is relentlessly changing. The purpose of this paper is to illustrate that the reductionist nature of different forms of essentialism causes many people continuous suffering. In other words, Larsen deploys the mulatto figure as a useful critical tool to explore how society is immersed in essentializing categories of race, class, gender and sexuality.

The paper describes approaches to assessing geohazards and georisk of economic losses in Moscow. It is shown that for surface construction, the principle geohazards in Moscow are karst-suffosion sinkholes, land subsidence, landslides, and waterlogging. The subsurface construction is endangered by karstification and fracturing of limestone, decompaction, and swelling of clay, quicksand phenomena, and groundwater breakthrough to tunnels. The different procedures for the assessment of geological risk in Moscow have been suggested for already existing urban infrastructure and for future planned construction. For existing surface urban infrastructure, geological risk is considered to be an integral parameter of probable damage caused by geohazards and the anthropogenic load on the specific territories. The main aim of risk mapping in this case is outlining the territories, for which restrictions and prohibitions should be imposed for further urban engineering development. For future subsurface urban construction, the risk-analysis consists in assessing the impact of geohazards on the engineering structure by comparing the future expenditures for the construction and operation under different engineering geological conditions. The procedures of risk mapping elaborated for both approaches are described; the typification schemes are listed; and the relevant risk maps built for the Moscow territory are provided. The risk maps will help planners to compare and make alternative project decisions in order to minimize the cost in future economic expenditures. Both approaches are successfully approved in Moscow.

The Pumice sand is a bright colored butian type, containing foam made from glass-walled bubbles and usually referred to as silicate volcanic glass granules. This pumice sand can be used as a substitute for normal sand as fine aggregate in a mixture of concrete mix. Based on the characteristic test examination, it can be seen that in testing the characteristics of pumice sand to the specifications of normal sand in specific gravity testing and weight testing of quicksand obtained results that are smaller than the specifications of normal sand and absorption tests obtained results greater than specifications on normal sand. The results of the normal sand compressive strength at BN is 250.95 kg /cm2 while the results of the floating sand concrete compressive strength on BPA is 224, 965 kg /cm2. Based on the research it can be concluded that with the same quality of concrete, the quality of K-250 is different in comparison to the compressive strength of concrete in normal sand and pumice sand concrete shows almost the same results. Therefore, more in-depth research is needed regarding the use of pumice sand instead of normal sand in a mixture of concrete mix

Scholars have highlighted Nella Larsen’s textual interventions into aspects of Edith Wharton’s major works. The interventions, they claim, not only unmask Wharton’s pointed operations of erasure against people of color but, in some cases, showcase her racism. None of these works, however, devote critical analysis to the interventions staged in Wharton’s The Custom of the Country (1913), the novel that, I argue, is her most definitive statement on the role of market-based capitalism on the fate of Western civilization. Larsen’s Quicksand (1928) shares many of Custom’s thematic concerns. Though writing from different class and racial perspectives, both writers must account for the social developments that spilled over from the previous century to articulate their implications for their heroines in terms of marriage, family, work, divorce, sex, and race relations on a trans-Atlantic scale. However, given that Custom almost entirely elides the presence of people of color, assessing it alongside Quicksand animates the specter of colonialism that haunts the text, inviting us to remember why not all bodies, as M. Jacqui Alexander argues in “Not Just (Any) Body Can Be a Citizen,” can be imagined as naturalized citizen subjects within the rubric of modern capitalism. Keywords: Nella Larsen, Edith Wharton, colonialism, capitalism, motherhood, racism

The aim of this paper is to analyse why Helga Crane cannot reach happiness due to her mixed origins and, therefore, her binary identity. The protagonist of Quicksand is constantly in quest of her selfhood, yet she is unable to find her so-much-longed-for sense of belonging. Helga cannot reconcile her two sides; besides, she feels she has to fight against this racial ambiguity that hinders the possibility of feeling complete. Due to her racial consciousness, our heroine is incapable of striking a balance between her two selves and this is precisely what makes her feel extremely miserable. L'objectiu d'aquest article és analitzar per què l'Helga Crane no pot assolir la felicitat degut als seus orígens mixtos i, per tant, a la seva identitat binària. La protagonista de Quicksand està constantment a la recerca de la seva personalitat, tot i això, és incapaç de trobar el seu tan anhelat sentit de pertinença. L'Helga no pot reconciliar els seus dos costats; a més, sent que ha de lluitar contra aquesta ambigüitat racial que dificulta la possibilitat de sentir-se completa. A causa de la seva consciència racial, la nostra heroïna és incapaç d'aconseguir un equilibri entre els seus dos jos i això és precisament el que la fa sentir extremadament desgraciada. El objetivo de este artículo es analizar por qué Helga Crane no puede alcanzar la felicidad debido a sus orígenes mixtos y, por tanto, a su identidad binaria. La protagonista de Quicksand está constantemente en busca de su personalidad, sin embargo, es incapaz de encontrar su tan anhelado sentido de pertenencia. Helga no puede reconciliar sus dos lados; además, siente que tiene que luchar contra esta ambigüedad racial que dificulta la posibilidad de sentirse completa. Debido a su conciencia racial, nuestra heroína es incapaz de lograr un equilibrio entre sus dos yoes y esto es precisamente lo que la hace sentir extremadamente desgraciada.

The contact part between shaft wall and rock is affected by many factors, such as temperature, formation pressure and so on, in the commonly used freezing method in coal mine development through quicksand and water-rich strata. In order to confine the relationships between these factors and the compressive strength of the contact surface, the sandstone which contacts with the outer well wall was selected in this study to prepare a complex of sandstone and C40 concrete mortar. The factorial design of the multi-factors affecting the uniaxial compressive strength of the complex specimens based on the freeze-thaw cycles test, the uniaxial compression test and the statistical principle was used to study the interactive effect of various factors. Significant analysis was performed via analyzing the sample water content, the freezing temperature and the number of freeze-thaw cycles based on the factorial design principle. The results show that the uniaxial compressive strength (UCS) of the dry sandstone-concrete complex specimens is significantly higher than that of the water-saturated sandstone-concrete complex specimens. After freeze-thaw cycles, the UCS of both the dry sandstone-concrete complex specimens and water-saturated sandstone-concrete complex specimens decrease significantly. In addition, the significant effects of main effect and primary and secondary interaction on unconfined compressive strength were obtained, and the major interaction among the factors was synergistic interaction, and the minor interaction among the factors is non-interactive interaction and antagonism.

Self-compacting concrete (SCC) mix designs exhibit complexities in their mechanical properties due to composite nature of the material and the multitude and variety of factors that affect such properties. In this paper, a set of SCC mix designs are made using silica quicksand (as filler) instead of rock powder with other required materials. The tests of fresh concrete such as the slump flow, J-ring, V-funnel, L-box tests and the hardened concrete tests are investigated and considered. The tests results are shown that, a high quality has been achieved for SCC mixture contains the quicksand and silica fume contents with low lubricant admixture dosage. The research is embodied the use of a branch of Artificial Neural Networks (ANN) as a quick and reliable alternative to such experimental testing. Results show that the ANN technique can perform as a satisfactory alternative to experimental testing to provide speedy prediction of optimum silica quicksand content must be added prior to SCC mix design. As such, proposed method for the SCC mix design are limited in scope and are approximate at best as they must rely on the results of experimental tests, which are both costly and time-consuming to perform.

Sinkers are quicksand enthusiasts that crave the sensation of being trapped in deep mud while being sucked downward. Although humans have been interested in quicksand over the years (particularly through film), there remains a void of research into the meaning and value in the lives of those who engage in a recreational pursuit of quicksand, most notably the community of individuals who self-describe as sinkers. The purpose of this exploratory study was to examine if sinking can contribute to a participant’s understanding of history and natural resources at state parks. In order to obtain a better understanding of the effects, a qualitative study was conducted in the summer of 2016 at Stephen C. Foster State Park, a state park adjacent to Okefenokee Swamp. The researchers exercised grounded theory techniques and inductive content analysis to analyze interview data and compile coded text into four main categories: learning, enjoyment, traveling, and economic impact. Findings suggest that participants believed their knowledge of park history and natural resources increased through a recreational pursuit of quicksand.

Civil structures are often built on sands, which are widespread in the upper part of the geological section. These soils usually serve as a reliable basis for engineering structures, but under certain conditions can cause large complications and even endanger the life safety. Analysis and generalization of the construction experience allows us educe three groups of problems that need to be identified and addressed timely. Most of the problems are related to water-bearing sands. Water flows, breakthrough of pressure water and quicksand are very common phenomena that complicate the excavation of construction pits and the device of underground structures. To protect against groundwater is often used dewatering, which can disrupt the stability of the surrounding buildings in high-density urban development. The second group of problems is related to the process of suffusion. The most dangerous of its manifestations are suffusion failures, leading to emergency situations and sometimes to the destruction of structures. The third group of problems is caused by specific reaction of sands to dynamic impacts, in particular, by liquefaction of water-saturated sandy soils. The consequences of such a reaction can be very serious: the immersion of the structure in the ground, the uplift of piles or bridge supports, the float up of underground tanks, the uplift of liquefied soils from under the foundation until the formation of a building tilt or overturning of the structure.

The 1920s marked a fervent time for artistic and literary expression in the United States. Besides the famous authors of the decade, including F. Scott Fitzgerald, Ernest Hemingway, and William Faulkner, Anzia Yezierska and Nella Larsen, among other female writers, also managed to carve “a literary space” for their stories. Yezierska and Larsen depicted the struggles and tribulations of minority women during the fermenting 1920s, with a view to illustrating the impact of ethnicity and race on the individual female identity. Yezierska, a Jewish-American immigrant, and Larsen, a biracial American woman, share an interest in capturing the nuances of belonging to a particular community as an in-between subject. Therefore, this essay sets out to examine the intersections of gender, race, ethnicity, and choice in shaping individual identities in public and private in-between spaces in Yezierska’s Salome of the Tenements (1923) and Larsen’s Quicksand (1928).

A 2,250 mm whirlpool foundation pit is located in Donghai Island, Zhanjiang City, Guangdong Province, China. The layers of the island are composed of multi-aquifers and multi-aquitards (MAMA). The aquifers are intersected by partial aquitard lenses. A large confined aquifer is frequently interbedded and separated into several sub-confined aquifers by partial aquitards. In the 2,250 mm foundation pit, the water level of two confined aquifers was reduced to satisfy excavation requirements and prevent water inrush. Construction of the 32.55 m deep foundation pit encountered MAMA and potential defects of the diaphragm wall. The pumping wells in the second confined aquifer were used to reduce the water level to ensure the safety of bottom excavation. The pumping wells in the first confined aquifer were used to reduce the water level under emergency conditions to prevent potential water inrush and piping from the defects of the diaphragm wall. Field pumping tests and numerical simulations were performed to determine the risk of leakage and verify the capability of the pumping wells to reduce the water level. Quicksand occurred during shallow excavation because of leakage although the confined aquifer had been cut off and pumped for a long time. Three pumping wells were installed to reduce the water level. When the foundation pit was excavated to a depth of 24 m, water inrush occurred at the middle of the pit bottom although the water level of the dewatered aquifer had been reduced to below the excavation face. A 90 m deep borehole was found where the underlying confined aquifer below the first aquifer induced the water inrush. Although the upper water level was reduced, the high water level in the deep part still induced water inrush. The pumping wells in the second aquifer were all opened, and the water level of the underlying confined aquifer was reduced. After the water level was reduced to below the pit bottom, the borehole was filled, and the water inrush stopped. However, water inrush occurred on the cracks of the diaphragm wall as predicted. The pre-installed pumping wells were opened to control the water inrush. The deepest foundation pit on the island was constructed successfully after dealing with the water inrush and leakages.

To obtain a comprehensive understanding on sand production and main factors affecting sand production in unconsolidated quicksand oil reservoirs during their production stage, the sand production processes under different conditions have been modelled. The modelling experiment was carried out on unconsolidated sand formation model made of water washed white sand, clay (kaolinite) and distilled water, by using a newly developed sanding modelling apparatus. The effects of drag force acting on the formation and formation cementation on sand production were analysed. The experimental results show sand and oil production rates both increase with the rise of drag force acting on the formation and decrease with the increase of cement content, and the sand production rate even approaches zero at high cement content. The reservoir with higher pressure is more likely to produce sand during development due to higher drag force, and drag force and effective formation stress jointly affect oil production. Therefore, the sand production rate can be estimated according to clay content, and proper sanding prevention measures can be taken correspondingly. In some cases, sand production in oil reservoirs can be much greater than that in gas reservoirs. Key words: quicksand reservoir, sand production, oil recovery, clay content, cementation degree, drag force

Jinan City is located in Eastern China, where porous water and karst water are well developed. The geographic position, geological environment, and terrain of Jinan provide many springs, most of which are distributed in urban areas. When metro lines are constructed in Jinan, six types of stratum combinations are typically encountered. Dewatering needs to be considered to avoid the occurrence of water-inrushing, quicksand and piping hazards, which can change the groundwater seepage environment and reduce spring discharge. In addition, the existence of metro lines can block the recharge channels of karst water. The effects of a metro system are felt on springs in three zones: shallowly buried areas of limestone, deeply buried areas of limestone and spring discharge areas. This paper proposes countermeasures to mitigate the impacts of metro lines on groundwater seepage and to protect springs. These measures include waterproof curtains, dewatering on demand, groundwater head monitoring, artificial recharge, tunnel waterproofing, and groundwater flow path systems.

The current plant recording system of the Botanical Garden of the Faculty of Science is a system stuck in time with a faded historical background. Intensive archival research was conducted to reconstruct and review the entire history of the plant recording system in the Garden and the data available in it. This way the organizational history is preserved for future generations and the knowledge and data collected for this article, will facilitate the Garden’s plant recording system moving into the 21st century., Povijest sustava za bilježenje zbirki biljaka u Botaničkom vrtu Prirodoslovno-matematičkog fakulteta i postupci u upravljanju njime većinom su nepoznati i nezabilježeni. Provedeno je arhivističko istraživanje radi povijesne rekonstrukcije upravljanja sustavom za bilježenje biljaka i uvida u kvantitativnu i kvalitativnu količinu povijesnih podataka o našim zbirkama. Ovim radom čuvamo dio povijesti upravljanja Vrtom za buduće generacije, dok će rezultati prikupljeni istraživanjem usmjeriti daljnji razvoj sustava za bilježenje biljaka u našem Botaničkom vrtu.

Gain score methods have long been criticized and avoided in educational and psychological literature and research. Using a novel research design that allows researchers to know the true causal effect in the presence of real, not simulated, confounding, this article provides empirical evidence that gain score methods can outperform ANCOVA in a real educational setting. Prevalent uninformed criticism on gain score methods should be discredited.

In his 2006 award winning monograph In Search of Nella Larsen: A Biography of the Color Line, George Hutchinson shed new light not only on the biographical facts of Nella Larsen’s life as a biracial individual coming of age during an “era when ‘race’ trumped” all relationships, even those of family, but also on the effects these experiences had on her psychologically, especially on her ability to forge a relational life. Given her socially and psychically untenable subject position as the “too dark to pass” child in a white family and the sense of isolation and, ultimately, abandonment, that attended it, it’s little wonder that Larsen’s autobiographically-informed fictional narratives can be read as sites of relational failure. In this article, I locate the narrative absences at the center of Larsen’s first novel, Quicksand, and examine the manner in which they source the relational failures that render the protagonist, Helga Crane, incapable of fulfilling her promise as, in Deborah McDowell’s words, a “daring and unconventional heroine” (xi). Not only does the palimpsestic presence of the black paternal impede Helga’s quest for social legitimacy and place, the present absence of the white maternal, arguably a more critical lacuna, serves as the experiential and psychological source of Helga’s fundamental “lack somewhere”: her failure to develop a relational subjectivity.

The present paper reports the application of a 2-D coupled fluid-particle simulation model with no macroscopic assumptions to the seepage failure of saturated granular soils. The basic problem of the seepage failure of a horizontal ground with an embedded sheet pile, where the system size is set to be 200 × 100 mm and the average diameter of the soil particle is 550 μ m, is numerically investigated. Both the seepage flow and the motion of the soil particles are directly solved by coupling the lattice Boltzmann method and the discrete element method. The goal of this study is to confirm that the 2-D direct simulation can be performed on the scale of a model experiment with soil particles that correspond in size to that of real sand. As a result of the analysis, it is shown that a typical series of behavior for seepage failure, where boiling and heaving initially occur on the downstream side near the sheet pile and finally lead to quicksand, can be seamlessly reproduced. Comparing the cases with different initial void ratios, it is found that the deformation area and the rates of the failure process can be varied according to the packing state. By tracking the velocity of each soil particle, it is visually shown that seepage failure begins to occur in the corner areas of the sheet pile much earlier than the onset of quicksand. By focusing on the fluid force acting on that particle, it is seen that the relatively large values for the hydrodynamic forces are concentrated on the upstream side before the beginning of uplift. In addition, by a comparison with two theories for the critical hydraulic gradient, the current limitations and problems of the proposed method are also summarized.

Tidore Islands has the potential of natural resources in the form of the availability of plenty of floating sand. This study was conducted to determine the effect of the use of floating sand as a substitute for sand on the characteristics of asphalt concrete mix wear (HRS-WC). This study uses the methods of The Asphalt Institute, Indonesian National Standards (SNI), and General Specifications 2018-Section 6.3. Percentage variation used in replacement material is 15% of normal sand: quicksand 15%, normal sand 7.5% : 7.5% quicksand, normal sand 11.25% : 3.75% quicksand and sand floating 11.25% : normal sand 3.75%. For find out the Marshall characteristics of the HRS – WC (Hot Rolled Sheet-wearing course) mixture by using a substitute for floating sand aggregate. Results of testing marshall with sand floating 11.25% sand normally 3.75% indicates the value of the stability of the highest = 1361.43 on levels of bitumen 6%, sand normal 15% to the value of the stability of the highest = 1408.6 at the level of asphalt 5.5%, the highest stability value = 1435.9 at 7% asphalt content, the highest stability value = 1472.2 at 6.5% asphalt content, and the highest stability value = 1687.8 at 6% asphalt content. And the average value of stability is 1473,19.

One of the determining factors for the efficiency of the main gas lines in Yakutia is their interaction with complex geotechnical and operating conditions. The most complex structures are underwater crossings of pipelines across the water bodies. Underwater crossings are among the high-risk systems; they are the most critical. The terms of accident elimination at underwater crossings are much longer than those of similar damage on the linear section of pipeline. Besides, their repair during operation is comparable in complexity and cost to the construction of a new underwater passage. This article provides data on conducting monitoring studies of the state of the Hatassy-Pavlovsk MGL across the channel part of the river Lena, determination of the planned-high-altitude positions of two pipelines on the floodplain sections of the route, on channel processes that affect SSS of welded joints of the pipes and determine the operational reliability and durability of the MGL.The determination of riverbed deformations in the area of the underwater crossing of the main gas line (MGL) is one of the most important issues of the research. Changes in the characteristics of the river flow, safety and service reliability of the underwater crossing of MGL across the river Lena depend on the riverbed deformations. The quicksand disturbance along the course of the river Lena significantly affects the nature of ice drift and spring floods. Due to the erosion of bottom sediments and soil heaving on the coastal slopes of the Hatassky channel, as well as its shallowing, the underwater crossing of the gas pipeline is completely seized by freezing ice and soil of the coastal slopes and is tightly clamped. Studies have revealed the seasonal loosening of the surface pipeline and scour at its underwater part, wearing away of the riverbanks, as well as anthropogenic impact under changing climatic conditions.

This paper presents a comprehensive investigation into weathered granitic gneiss in Guangzhou, China, including its formation, grading, classification, and the geotechnical characteristics of different weathered states. The granitic weathering profiles are graded into five weathered states: fresh rock, slightly weathered, moderately weathered, highly weathered, and completely weathered. The fresh rock and the slightly weathered rock have good mechanical behaviour. The highly weathered granitic gneiss was found to possess a relatively higher permeability than the other weathered states, in which the fissure water is usually stored. Geotechnical characteristics of the weathered granitic gneiss that poses geohazards during excavation are identified, including: (1) uneven grain size distribution, (2) water softening of the residual soils, and 3) spherical weathered boulder. The following potential geohazards are identified: (1) quicksand and piping, (2) water–ground settlement or even collapse due to water softening, (3) trenching difficulties in a diaphragm wall, and (4) instability of the lattice columns. Countermeasures for preventing these geo-hazards are proposed, including (1) rate-controlled drilling of dewatering wells, (2) grouting in both sides of retaining walls, and (3) deep hole blasting of large-size residual gravel boulders. These measures has been demonstrated to be useful in construction of Zhongxin Station.

An Air cushion vehicle is a vehicle that flies like a plane but can float like a boat, can drive like a car but will traverse ditches and gullies as it is a flat terrain. An air cushion vehicle also sometimes called an air cushion vehicle because it can hover over or move across land or water surfaces while being held off from the surfaces by a cushion of air. A Hovercraft can travel over all types of surfaces including grass, mud, muskeg, sand, quicksand, water and ice .Hovercraft prefer gentle terrain although they are capable of climbing slopes up to 20%, depending upon surface characteristics. Modern Hovercrafts are used for many applications where people and equipment need to travel at speed over water but be able load and unload on land. For example they are used as passenger or freight carriers, as recreational machines and even use as warships. Hovercrafts are very exciting to fly and feeling of effortlessly traveling from land to water and back again is unique.

Behavioral economics lacks empirical evidence on some foundational empirical questions. We adapt standard elicitation methods to measure multiple behavioral factors per person in a representative U.S. sample, along with financial condition, cognitive skills, financial literacy, classical preferences and demographics. Individually, B-factors are prevalent, distinct from other decision inputs, and correlate negatively with financial outcomes in richly-conditioned regressions. Conditioning further on other B-factors does not change the results, validating common practice of modeling B-factors separately. Corrections for low task/survey effort modestly strengthen the results. Our findings provide bedrock empirical foundations for behavioral economics, and offer methodological guidance for research designs.

A quicksand disaster through a borehole occurred in Longde coal mine. A lot of aeolian sand, the volume of which is between 310,000 m3 and 380,000 m3, has submerged into the underground space in about 70.5 h. The volume flux of quicksand cannot be calculated accurately by the empirical method. Based on the method of fluid mechanics, an all-purpose computing method for quicksand disaster through a borehole was proposed. The result shows that the inrush volume of sand into underground space was between 310,000 m3 and 350,000 m3, which was consistent with the actual result. To apply and popularize this method, the impact laws of water yield properties of an aquifer on the volume flux were discussed. The all-purpose computing method can be suitably used for the volume flux calculation of quicksand disaster through the borehole.

The article presents the features of transformation and migration of petroleum products in the underground environment, which are determined by the physical and physicochemical properties of petroleum hydrocarbons (density, viscosity, solubility in water, etc.) and their enclosing soils (sorption capacity, humidity, etc.). The main processes of degradation of oil products in the soil stratum are considered. The influence of oil products on the change in oxidation-reduction and acid-alkaline conditions of the underground space, development of activity of various forms of microorganisms is shown. The change in the composition and properties of dispersive soils of various degrees of water saturation is experimentally studied. The analysis of the causes of the reservoir destruction used for storage of fuel oil is given. It was established that the development of microbial activity at its base led to the transition of sands to quicksands, and moraine loams to quasi-plastic varieties. Intensive gas formation of methane and its homologues, nitrogen, carbon dioxide, hydrogen in sands was recorded. Based on the analysis of the results of long-term monitoring of the effect of contamination of dispersive soils by oil products, their bearing capacity in the base of the structures has been reduced to 50% of the initial value. The role of microbial activity in the formation of an aggressive environment in relation to building materials is shown.