Yellow Clay Research Articles

Valorization of wood sawdust in making porous clay brick

This paper studies the application of a variety of sawdust materials in the production of lightweight insulating bricks. First, the mineralogical and chemical composition of clays was determined. Next, ceramic bricks were fabricated with different quantities of materials (3 to 6 and 9 wt. % for sawdust, 65 wt. % for grey clay, 24 to 27 and 30 wt. % for yellow clay and 2 wt. % of tuff). These bricks were fired at 800 and 950°C. The effect of adding this sawdust on the technological behaviour of the brick was assessed by drying and firing shrinkage, water absorption, porosity, bulk density and compressive strength. The results have shown that the optimum sintering temperature is 950°C. Below this temperature, at 950°C, increased open porosity was observed, which decreased the compressive strength of the bricks. Based on the results obtained, the optimum amounts of waste were 9 wt. % sawdust of eucalyptus, 24 wt. % shaping moisture and 1.6 particle size diameter. These percentages produced bricks whose mechanical properties were suitable for use as secondary raw materials in ceramic brick production. Key words: Clay brick, absorption, porosity, sawdust, mechanical properties.

Utilizing the algicidal activity of aminoclay as a practical treatment for toxic red tides

In recent decades, harmful algal blooms (HABs) – commonly known as red tides – have increasingly impacted human health, caused significant economic losses to fisheries and damaged coastal environments and ecosystems. Here, we demonstrate a method to control and suppress HABs through selective algal lysis. The approach harnesses the algicidal effects of aminoclays, which are comprised of a high density of primary amine groups covalently bonded by metal cation backbones. Positively charged colloidals of aminoclays induce cell lysis in HABs within several minutes exposure but have negligible impact on non-harmful phytoplankton, zooplankton and farmed fish. This selective lysis is due to the ammonium characteristics of the aminoclay and the electrostatic attraction between the clay nanoparticles and the algal cells. In contrast, yellow loess clay, a recognized treatment for HABs, causes algal flocs with little cell lysis. Thus, the aminoclay loading can be effective for the mitigation of HABs.

Archaeological excavations at Gamzigrad - Romuliana in 2007-2008

Archaeological excavations at Gamzigrad - Romuliana in 2007-2008

해양퇴적층에서 적조생물(Cochlodinium polykrikoides)의 혐기성 분해과정 중 황토가 휘발성 지방산 생성에 미치는 영향

The formation of volatile fatty acids(VFAs) and changes in pH, oxidation and reduction potential(Eh) and acid volatile sulfide(AVS) with the addition of yellow clay were investigated using microcosm systems to examine the effects of yellow clay dispersion on the anaerobic decomposition of Cochlodinium polykrikoides in marine sediments. The acetate concentration reached a maximum by day 4 and was 1.2-1.8 fold less in the sample treated with yellow clay compared to the untreated sample (224-270 vs. 333 uM). The formate concentration reached a maximum by day 1 and was 1.3-2.8 fold less in the sample treated with yellow clay compared to the untreated sample (202-439 vs. 563 uM). The propionate concentration reached a maximum by day 2 and was 1.5-1.8 fold less in the sample treated with yellow clay compared to the untreated sample (32.6 vs. 57.2 uM). After the amounts of acetate, formate and propionate peaked the levels dropped dramatically due to the utilization by sulfate reducing bacteria. The Eh of the samples treated with yellow clay was similar to the untreated sample on day 0 but was higher in the sample treated with yellow clay(140-206 mV) from days 4 to 17. AVS started to form on day 3 and this was sustained until day 6, and 1.2-2.2 fold less was produced in the sample treated with yellow clay compared to the untreated sample (40.2-69.3 vs. 83.2-93.8 mg/L). Accordingly, during the anaerobic decomposition of C. polykrikoides in marine sediments, yellow clay dispersal seems to suppress the reduction state of Eh and the formation of volatile fatty acids(acetate, formate and propionate) used as an energy source by sulfate reducing bacteria, indicating that this process controls the production of hydrogen sulfide that negatively affects marine organisms and the marine sediment environment.

Lystrup Østergård – En værkstedsplads fra yngre stenalder

Lystrup Østergård – En værkstedsplads fra yngre stenalder

FAILURE PROCESS ANALYSIS OF CARSINGTON DAM USING EXTENDED FINITE ELEMENT METHOD

Previous studies ignored the possible contribution of the yellow clay interlayer to the failure mechanism of Carsington earth dam, and these studies were mainly based on conventional finite element method, which can neither describe discontinuous displacement field such as shear band visually, nor be able to investigate the formation of shear band and the evolution of the mechanics behavior of soils. In this paper, a self-developed simulation system for the evolution of shear band in soil based on the extended finite element method is applied to simulate the failure process of Carsington dam. The results show that the simulation system is able to trace the path and evolution of shear band in the central core of Carsington dam, and reveales the failure mechanism of Carsington dam reasonably, which proves the applicability of this simulation system in complicated structures and stress conditions.

Antibacterial Effect of some Mineral Clays In Vitro

Background:- The use of geological mineral clay to heal bacterial infections has been evident, since the earliest recorded history, and specific clay minerals may prove valuable in the treatment of bacterial diseases, including infections for which there are no effective antibiotics, such as multi-drug resistant infections. Objectives:- The aim of this study is to identify new inhibitory agents in an era when bacterial antibiotic resistance continues to challenge human health and the availability of new antimicrobial compounds is limited. Materials and methods:- Two bacterial isolates were taken from patient with different infections (UTI, skin infection). The two isolates were used to study the antibacterial effect of four types of mineral clays (gray clay, yellow clay, white clay, and pink clay). Result:- Three types of clays (white clay, gray clay, and yellow clay,) have an antibacterial effect against Staphylococcus aureus that was isolated from skin infection. And have no effect against Pseudomonas aeruginosa that was isolated from patient with UTI. On the other hand, pink mineral clay explained an antibacterial effect against Pseudomonas aeruginosa, and has low effect against Staphylococcus aureus. Conclusions:- Our results indicated that mineral clay could provide an alternative treatment against numerous human bacterial infections.

Sintering and characterisation of ceramics containing paper sludge, glass cullet and different types of clayey materials

The present paper reports on the sintering behaviour of several ceramics prepared using a previously selected mixture of incinerated paper mill sludge and glass cullet in the ratio 60/40 which was blended with 10, 20, 30 and 40wt.% of three different natural materials. The three natural products were: a red quartzitic clay, a yellow quartzitic clay and a kaolin. All mixtures were blended by attrition milling and dried; powders were sieved, pressed into specimens and fired for 1h at temperatures ranging from 1040 to 1140°C. The resulting materials were characterized by water absorption, shrinkage, crystallographic composition, microstructure and physico-mechanical properties. It was observed that materials containing kaolin display the best overall behaviour independently of the quantity of kaolin introduced. Conversely the optimal sintering temperature, and consequently the best properties of the materials prepared using red or yellow clay were measured on products fired at temperatures above 1080°C; materials and temperatures are affected by the amount of clay added.

Biserica evanghelică din Saschiz, jud. Mureş. Cercetări arheologice (I)

Localitatea Saschiz (Keisd, Sászkézd vára) se află în partea de sud-est a Transilvaniei, în zona de colonizare săsească, originile sale medievale fiind de căutat în secolele XI– XII. Prima menţiune documentară datează din 1309, iar în secolele XIV– XV era o localitate de importanţă regională, comparabilă în multe situaţii cu Sighişoara. Biserica evanghelică a fost construită în stil gotic târziu în intervalul 1493– 1525, originalitatea ei fiind dată de proiectul arhitectural care a inclus de la început componentele necesare unei duble funcţiuni, biserică şi în acelaşi timp fortificaţie care poate asigura refugiul şi apărarea eficientă a locuitorilor în cazul unui pericol neaşteptat. Biserica este alcătuită dintr-o sală de dimensiuni mari, un cor alungit încheiat cu o absidă poligonală şi o sacristie pe partea de nord, alipită corului şi supraetajată, astfel încât din exterior are aspectul unui mic turn – toate acestea suprapuse de un etaj de apărare ieşit în consolă şi sprijinit pe contraforturi. Un turn fortificat este amplasat pe latura de nord, la cca 10 m distanţă de biserică. Cercetarea arheologică s-a derulat în contextul deschiderii unui şantier de restaurare în intervalul 1999– 2010, fiind concentrată pe suprafeţe relativ restrânse în exteriorul bisericii, în interiorul turnului şi în interiorul corului. Articolul prezintă cercetările efectuate asupra bisericii, urmând ca investigaţiile din zona turnului, cimitirul şi materialele arheologice descoperite să fie publicate ulterior. Cercetarea arheologică a stabilit că biserica formată din navă, cor alungit încheiat cu absidă pentagonală şi sacristie pe latura de nord, a fost construită într-o singură etapă, inclusiv contraforturile fiind prevăzute în proiectul iniţial. În jurul bisericii s-a dezvoltat un cimitir din care au fost cercetate peste 30 de morminte. Deşi săpăturile au fost relativ restrânse, putem concluziona că nu a existat un lăcaş de cult mai vechi pe acelaşi amplasament. Niciun fel de vestigii care să poată fi legate de o astfel de etapă nu au fost identificate, prin vestigii înţelegând ruine, depuneri stratigrafice, cimitir aferent sau artefacte care să poată documenta o astfel de prezenţă. Literatura de specialitate mai veche a susţinut constant o astfel de evoluţie, în care vechea biserică a comunităţii săseşti, probabil o bazilică din secolul al XII-lea, a fost suprapusă mai mult sau mai puţin direct de biserica sală fortificată de la sfârşitul secolului al XV-lea. O astfel de teorie a fost susţinută de prezenţa unui mic lapidariu în interiorul bisericii, de refolosirea unor pietre profilate în clădirea gotică, şi desigur de faptul că în mod firesc lucrurile au evoluat în acest fel în majoritatea comunităţilor săseşti din sudul Transilvaniei, între bisericile din diferite etape conservându-se o continuitate spaţială. La Saschiz realităţile constatate arheologic nu confirmă însă un astfel de scenariu, fiind evident faptul că biserica romanică a funcţionat pe un alt amplasament, împreună cu cimitirul aferent, rămas probabil până la Reformă cimitir principal al comunităţii.

Correção granulométrica de solos para aplicações em estradas florestais: estudo de caso com solos da CENIBRA

Este artigo apresenta um procedimento para estudo do comportamento mecânico de três solos oriundos da empresa CENIBRA S. A., localizada na cidade de Belo Oriente, Minas Gerais, Brasil, para fins de emprego em revestimento primário, reforço de subleito e sub-base de estradas florestais, classificados como argila amarela, argila vermelha e areia. Empregou-se, nesta investigação, a técnica de estabilização mecânica de solos com correção granulométrica. O programa de ensaios de laboratório englobou o uso de várias composições percentuais de solos, com base na mistura entre dois deles, de modo a obter um produto final eficiente para aplicações nas estradas florestais da CENIBRA S. A. Trabalhou-se com os percentuais de 60, 70 e 80% de areia e de 20, 30 e 40% das argilas nas composições das misturas, compactando estas na energia do ensaio Proctor Modificado. A melhor resposta mecânica foi obtida pela mistura de 80% de areia e 20% de argila amarela, com capacidade de carga representada pelo ISC de 63%.

Paleoseismic evidence and repeat time of large earthquakes at three sites along the Longmenshan fault zone

In historical records, no earthquake of magnitude comparable with that of the Wenchuan Mw 7.9 earthquake has ever been reported in Chengdu and Longmenshan regions. It is important, therefore, to assess if there is any evidence of prior large earthquakes in the recent geological record. In order to explore this problem, 3 trenches were excavated separately at 3 sites along the surface rupture zones in the middle segment of the Beichuan–Yingxiu Fault and Jiangyou–Guanxian Fault of the Longmenshan fault zone, and the offsets of geomorphic surfaces were measured in the trenches. The basic facts of recurrence of large earthquake on the seismogenic fault of the Wenchuan earthquake are demonstrated in this paper on the basis of the accumulated deformation amounts of old and young geomorphic surfaces as well as the paleoearthquake events revealed in the trenches. The document that at Leigu along the Beichuan–Yingxiu Fault, at Bailu along the Jiangyou–Guanxian Fault, and Xiaoyudong on a NW-trending fault, the height of fault scarp on the second terrace has a multiple relationship to that on the first terrace after the Wenchuan earthquake of 12, May. The elevation difference of the marker horizon (the yellow sandy clay bed) of the second terrace revealed in the trenches on both sides of the fault is nearly twice (or three times larger in Bailu) of that produced by the Wenchuan earthquake. These observations suggest the occurrences of paleoearthquake events with surface deformation comparable to that produced by the Wenchuan Mw 7.9 earthquake. According to the dating data and the fact that there is no such slip of comparable paleoearthquakes in the 2300-year-long historic literature in Longmenshan region, we suggest that the penultimate event occurred between 2300 a BP and 3300 a BP.

Holocene sedimentary record from Lake Tutira: A template for upland watershed erosion proximal to the Waipaoa Sedimentary System, northeastern New Zealand

A Holocene lake record from northeastern New Zealand provides a detailed record of environmental controls on upper watershed sedimentation, and is proximal to the Waipaoa MARGINS Source-to-Sink focus site. In that context, Lake Tutira in Hawke's Bay was cored in 2003 to recover a complete sedimentary record since the lake's formation ca 7.2 ka. The 27.14 m-long core contains alternating lithotypes that are sedimentary responses to lacustrine organic accumulation, normal to severe rainfalls, earthquakes and volcanism. A diatom allochthonous ranking scheme, pollen counts, and C and N percentages were used to identify intra-lake and watershed-derived storm deposits and modes of lithotype deposition. The lithotypes and depositional modes are: tephras (volcanic airfall); organic-rich mud (algal-rich lake sedimentation); massive to weakly graded, brown silty clay beds (homogenites and redeposited lake sediments); grey, graded sandy mud beds (intense storm-delivered sediment); and, thin yellow clay layers (run-off from small storms). Using 12 tephras and 3 radiocarbon ages to provide a chronology, the long-term sedimentation rate is ca 3.3 mm/year, which increases to > 10 mm/year following European colonisation. Storm beds occur in response to rainfall events, with no obvious correlation to El Niño-Southern Oscillation polarity or strength. Moreover, no single climate index appears to correlate strongly with the historic rainfall event record. Having characterised and identified storm-beds over the lake's history, a hindcast relationship implies that around 53 pre-historic storms occurred with a magnitude similar to the severe Cyclone Bola event of 1988, plus 7 potentially larger storm events. Despite the prominence of storm beds, a summation of the total percent thickness as an indication of the relative modes of emplacement for each lithotype shows that proportionally, the balance of intra-lake versus storm sources preserved in the lake bed is 69% and 26%, respectively. As well as storms, lake sedimentation is strongly influenced by earthquakes that destabilize the terrigenous, sediment-laden lake margins to generate homogenites, represented by the brown silty clay beds. These deposits tend to be thicker after a hiatus in seismic activity and after sustained periods of lake-margin loading, as inferred from the occurrence of thick graded storm beds. Comparison with marine records on the adjacent continental margin suggests that more terrestrial events are captured in the lake record, due to: (i) close hillslope–lake connectivity, with little intervening storage of sediment compared with the Waipaoa sedimentary system; and, (ii) the preservation of event stratigraphy at Tutira compared to its reduced preservation in the dynamic marine environment. Only major storms such as Cyclone Bola leave an imprint traceable to the ocean, whereas identifiable sedimentary responses to individual earthquakes are localized, although through landscape preconditioning and sediment production they contribute to the overall high terrigenous input to the ocean. In contrast, low-frequency, high magnitude perturbations (volcanic eruptions, European deforestation) are preserved through the Source-to-Sink sedimentary system, consistent with earlier hypotheses.

The K/Pg boundary at Brazos-River, Texas, USA — An approach by marine palynology

Two cores and one outcrop section from the Cretaceous/Palaeogen (K/Pg) boundary interval at the Brazos-River area, Texas, USA, have been high resolution sampled and analysed fully quantitatively by marine palynology. The results have been compared and integrated with data from micropalaeontology, sedimentology and isotope-geochemistry from the same sections. Within all three sections, the K/Pg boundary, defined as the base of the P0 foraminifera zone and the onset of a negative carbon isotope anomaly, closely corresponds to the appearance of lowermost Danian organic-walled dinocysts. Based on various palynological proxies as well as on sedimentologic features, a sequence stratigraphic subdivision of the sections is proposed. From a synopsis of all three sections, a long term, punctuated drop of relative sea-level is indicated, starting at about the top of the Upper Cretaceous CF2 foraminifera zone and reaching a minimum within the upper P1a zone of the Lower Palaeogene. This is followed by a prominent transgression starting within the P1a/P1b boundary interval. The “event deposit” (ED), a siliciclastic unit located well below the base of the P0 foraminifera zone in the present sections, most probably represents a combination of both episodic relative sea-level fall and lag deposit due to initial transgression. It is preceded by significant fluctuations of climatic boundary conditions, with cool climates correlating to heavier δ 13C values and increased p/g ratio of dinocysts, suggestive of higher marine primary productivity. Across the K/Pg boundary, a prominent increase and spike of the warm–temperate waters dinocysts fraction is documented, represented mainly by Trithyrodinium evittii, which is accompanied by climatic warming and an episodic relative sea-level rise. Thus, prominent paleo-environmental changes and sea-level fluctuations precede and coincide with the K/Pg boundary proper. These data are inconsistent with a single “catastrophic” impact as the cause for the K/Pg boundary event, but suggest relative longer term environmental stress as finally leading to End-Cretaceous crisis of the biosphere. Between the ED and the K/Pg boundary proper, the gradual increase to peak abundance in trilete spores demonstrates a significant time lag between these two horizons. According to the distinct distribution of this peak abundance, it cannot be excluded that an impact/tsunami event is related to the lower portion of the ED. In contrast, no significant changes within most palynologic proxies are documented across the yellow clay layer below the ED documented within one of the sections and recently suggested as the original Chicxulub impact ejecta horizon. This questions the impact origin of this horizon or, at least, suggests only little consequences of this event on the ecosystem.

전산화 공정을 이용한 조류제거

The blue-green algae which caused odor problem in the tap water are difficult to precipitate in sedimentation basin and clogged the filter void rapidly. The studies of this paper were not only oxidation, coagulation and sedimentation processes for effectively removing blue-green algae but yellow clay and polyamine for verification as coagulants aids. The results of this research are summarized as follows: Higher ozone dose(C) and longer contact time(T) were needed for a high degree of removing blue-green algae efficiency. the removal rate of blue-green algae was proportional to the <TEX>$C\times T$</TEX> value. The removal percent of chlorophyll-a by sedimentation and filter without pre-ozonation was about 75% but 1 mg/L pre-ozonation could increase the removal percent of chlorophyll-a to 99% and more pre-ozonation could remove completely. Though the removal efficiency of turbidity could increased by high dose of chlorination, the dissolved organic carbon was increased. More chlorine dose from 4 to 10 mg/L dissolved organic carbon was decreased. Using yellow clay as coagulant aids increased density of floc so the settling velocity of floc become rising but polyamine could not increase settling velocity of floc though it could formated large floc.

Kinetics and thermodynamics studies for the removal of Co2+ and Cs+ from aqueous solution by sand and clay soils

The adsorption parameters of local yellow sand and clay towards cobalt and cesium were investigated by batch equilibration technique. The influences of equilibration time, initial metal concentration, solution pH, volume of aqueous solution to weight of adsorbent ratio and temperature have been studied and discussed. Cobalt and cesium removal from 0.1 M sodium chloride solution were quantitatively evaluated using Langmuir and Freundlich isotherm models. The two tested models fit the data reasonably well. The maximum removal capacity of clay was found to be greater than that of yellow sand for both ions and the mean free energy in all cases in the range corresponding to ion exchange mechanism. The values of the first order rate constants, the rate constants of intraparticle transport and the particle diffusion coefficients for cobalt and cesium ions were determined from the graphical representation of the proposed models. The removal studies were also performed at different temperatures to obtain the thermodynamic parameters of the process.

Mechanism for the rapid motion of the Qianjiangping landslide during reactivation by the first impoundment of the Three Gorges Dam reservoir, China

The first impoundment of the Three Gorges Dam reservoir in China started from a water surface elevation of 95 m on June 1, 2003 and reached 135 m on June 15, 2003. Shortly after the water level reached 135 m, many slopes began to deform and some landslides occurred. The Qianjiangping landslide is the largest one; it occurred on the early morning of July 14, 2003 and caused great loss of lives and property. Field investigation revealed that, although failure occurred after the reservoir reached 135 m, the stability of the slope was already reduced by preexisting sheared bedding planes. To study the mechanism of the rapid motion of this reactivated landslide, two soil samples were taken from a yellow clay layer and a black silt layer in the sliding zone, respectively, and a series of ring shear tests were conducted on the samples. One series of ring shear tests simulates the creep deformation behavior, while the other series simulates different shear rates. Conclusions drawn from analysis of the ring shear tests indicate that the mechanism of the rapid motion of the reactivated landslide was caused by the rate effect of the black silt layer during the motion phase after the creep failure. The yellow clay layer did not play any important role in the rapid motion in the 2003 event.

From Byzantine to post-Byzantine art: the painting technique of St Stephen's wall paintings at Meteora, Greece

The old katholikon of St Stephen's monastery at the Meteora (site of the most important complex of monasteries in Greece after Mount Athos) is decorated with wall paintings that date from the beginning of 17th century. In terms of style, the artistic ensemble is altogether characteristic of the period. The painting technique has been examined by means of μRaman and μFTIR spectroscopies, gas chromatography–mass spectroscopy (GC/MS), optical microscopy (OM) and scanning electron microscopy (SEM). Prior to the commencement of restoration treatment, and in order to optimise its effect, it was considered prudent to identify the materials and ascertain the techniques that had been used to apply the plaster and the paint layers. It was noted that whereas the ariccio consists of yellow clay and straw, the intonaco contained calcite. The painter's palette is made up of eight pigments: calcite, carbon black, yellow ochre, haematite, green earth, cinnabar, smalt and malachite. The stratigraphy and the scale of the shades differ significantly from those in works of the Palaeologan period (1261–1453) – indicative both of evolution in Byzantine iconography as a result of gradually changing religious and social circumstances, and of the skill and vision of the painter. In addition, some decay products, such as gypsum, were detected. In that they conceal important artistic details, this necessitates proper consolidation, cleaning and conservation treatment in order to restore to some degree the original splendour of the wall paintings.

Evaluation of Clay Added Nonwovens as Filter in Waste Landfill

In this, study, the yellow clays were added to the nonwoven geotextiles to improve the removal effects of the toxic and organic components of the leachate solutions which are very dangerous to the men's health. 4 types of functional nonwoven geotextiles were manufactured with the different composition of yellow clays. We applied these functional nonwoven geotextiles to the waste landfill fields as a filtration material of leachate solutions and tested tensile properties before/after application. Chemical and biological resistances of these nonwoven geotextiles were also evaluated and the amounts of absorptions of toxic and organic components were compared to the simply manufactured polyester nonwoven geotextiles.

Effect of yellow clay on respiration and phytoplankton uptake of bivalves

Yellow clay dispersion has been applied to mitigate red tides in Korea since 1995. The present study documents the effect on physiology of two marine bivalves by examinations of clay uptake, respiration, and clearance rate (CR) of animals after the treatment of yellow clay. The amount of clay in gills and inside cavities of shellfish was increased with time, and the inside of the shellfish filled with clay in 2 h. The ejection of the accumulated clay wasevident from as early as 30 min after removal from clay pools. Animals removed from the clay pool discharged all observable clay by 6 h. Within 30 min, CR decreased quickly and returned to the level of the untreated control groups within 2 h.

Enhancement of insulating properties of brick clay by renewable agricultural wastes

The use of agricultural wastes (byproducts) in various segments of brick and tile industry is increasing continuously. These additives, which are previously mixed into the raw or compound clay, start to ignite during the firing process, providing extra thermal energy inside the product and decreasing the required external energy need. Besides this effect, the combustion of additives increases the porosity of the final product resulting in enhanced thermal insulation properties. In this paper the effect of some common agricultural wastes (sawdust, rice-peel and seed-shell) on the thermal properties of brick clay products was investigated. The brick samples were prepared from the mixture of the yellow and gray clay in the ratio of 4:1, water content was between 15.57-16.67 wt.% and the pore-forming additives in concentrations 0, 4 and 7 wt.%. To measure the steady state thermal conductivity of the clay mixtures, samples with dimensions of 300?300?50 mm were prepared. Drying and firing were performed using the industrial partner?s standard procedures. Precise thermal conductivity data was measured, using a RAPID?K type static thermal conductivity instrument. The results showed that increasing the quantity of agricultural byproducts in the clay mixture significantly decreases the thermal conductivity of the final products, while only a minor reduction in the mechanical strength was observed. It was found that the most efficient byproduct additive was the sunflower seed-shell. With the addition of only 7 wt.% seed-shell to the basic clay the thermal conductivity decreased from 0,27 W/m?K to 0,17 W/m?K (i.e. ~36%).