Loose Grains Research Articles

Dolostone pulverization induced by coseismic rapid decompression of CO2-rich gas in nature (Matese, Apennines, Italy)

South Matese, Apennines, is a hydrothermally and seismically active extensional area characterized by CO2 outgassing and Mw≤7.1 earthquakes. There, meters-sized pockets of incohesive pulverized dolostone are hosted within Mesozoic carbonates at the hanging wall of seismically active normal faults. The aim of this paper is to understand the pulverization process. The pulverized dolostone is finely comminuted (down to a few microns), but primary structures, mainly bedding, are preserved. The grain size distribution is similar to that of previously studied pulverized rocks associated with active faults and dissimilar to that of carbonate cataclasites and fault gouges. The pulverized pockets are surrounded by zones (halos), in which the loose grains are cemented, in their original position, by microcrystalline calcite, resulting in a cemented micro-mosaic breccia. Stable isotopes from the cement are compatible with calcite precipitation from rapidly CO2-degassing shallow waters. Comparing our observations with results of laboratory experiments on carbonate pulverization through rapid decompression of pore-hosted CO2, the best explanation for the pulverized dolostone may lie on local accumulations of pressurized CO2-rich gas, suddenly decompressed during earthquakes. The limited permeability of the gas-saturated dolostone must have prevented a prompt escape of the gas from the rock, which was therefore anhydrously pulverized by the rapid expansion of the trapped gas. The sudden decompression must have suctioned bicarbonate-rich groundwaters, from which microcrystalline calcite rapidly precipitated, fossilizing the freshly pulverized dolostone. Calcite precipitation formed an impermeable shield around the pulverized pockets, which, therefore, remained internally uncemented. This process may have occurred over multiple cycles at depths shallower than the CO2 subcritical–supercritical boundary (ca. -800 m). Although hypothetical, the proposed mechanism is for the first time suggested for an active tectonic environment. The gas rapid decompression could have been triggered by coseismic processes (e.g., dynamic unloading or transient tensile pulses) previously proposed for the formation of other pulverized rocks. The presented case may improve our knowledge of possible chemical-physical processes connected with the subsurface storage of CO2 in seismically active areas.

Approach to fly in roadbed cobnstrction

Nowadays, filling sand is mainly used for roadbed construction. However, this material resource is gradually depleting. At the same time, sand has loose grain structure and small elastic modulus (E ≤ 40Mpa) therefore it fails to meet the technical requirements of roadbed construction. Consequently, roadbed is often embanked with alternative materials such as soil reinforced with inorganic binders, natural aggregates, and macadam. leading to high cost and environmental pollution. Therefore, it is important to determine a new type of roadbed material. This study presents several laboratory tests on the mechanical and physical properties of sand mixed with fly ash in order to find an appropriate mixture for roadbed construction. The test results show that the mixture of sand and fly ash, which contains an optimal ratio of sand/fly ash of 70%/30% with a dry volume value of 1.821g/cm³, not only meets the requirements for roadbed materials, but also utilizes more fly ash. When adopting Geopolymer technology where alkaline solution is added to reinforce sand-fly ash mixture with the ratio of sand/fly ash of 70%/30%, fly ash will be activated by the alkaline solution to produce gelatinous material through a series of reactions. The gelatinous material is characterized by the high-strength and the tightly-linked molecules. Apart from being a suitable material for roadbed construction, sand fly ash material can also be used as a foundation layer for pavement structure

Cryogenic ridges: a new speleothem type

Cryogenic cave carbonates have been described from several formerly or presently glaciated karst caves. In most of these occurrences, they precipitated as loose grains or aggregates with various morphologies and sizes. Here, we report on a new speleothem type (cryogenic ridges) identified in Sohodoalele Mici Cave (SW Romania) within a large chamber near the entrance shaft. This study was motivated by the presence of a network of calcite ridges over the stalactites’ surface and by the observation that during winter, these speleothems are covered by a thin ice layer. The higher δ18O (−3.5 to –1‰) and δ13C (0 to 7‰) values found in the calcite ridges relative to δ18O (–7.5 to –4‰) and δ13C (–9 to –2‰) values of calcite from the inner stalactite indicate that the ridges are of cryogenic origin and formed during relatively rapid carbonate precipitation associated with evaporative cooling and freezing of the water. Four U-series ages suggest that the stalactites with ridges formed during cold winters of the Holocene, when cave air temperatures dropped below freezing.

Combing the standing crops with preliminary separation of loose grains

SUBJECT OF THE STUDY: Is the process of preliminary separation of loose grains from combed grain heap on the slatted bottom of the feed elevator of a combine harvester.
 AIMS: Is an efficiency evaluation of the combed grain heap separation on the slatted bottom of the inclined chamber of a combine harvester in the field and to compare the degree of crushing of free grain depending on its supply to the threshing device or directly to the cleaning system.
 METHODS: All studies were carried out on winter wheat of the Moskovskaya 56 variety with a yield of 30 c/ha. Plant height varied within 0,60,9 m with a grain ripeness of at least 98% and a moisture content of 14%. The serial grain header ZHO-5 OZON manufactured by PJSC Penzmash was aggregated by the Niva-Effect combine harvester with a constant speed of 8 km/h and a stripping cylinder speed of 485 min-1. The field experiments were divided into two stages. The first series of experiments was devoted to evaluating the efficiency of preliminary separation of combed grain heap on the slatted bottom of the experimental feed elevator. During the second series of the experiment, grain was harvested with a serial feed elevator without its preliminary separation.
 RESULTS: According to the results of the first series of studies, it was found that the passage of loose grain through the holes of the slatted bottom of the inclined chamber is 91,6%. At the same time, grain crushing in the feed elevator did not exceed 0,5%, and in the bunker 1,75%. During the operation of the combine with a serial feed elevator without preliminary separation of the combed grain heap, the crushing of the bun-ker grain was within 5,25%.
 CONCLUSION: The practical implementation of such a technical solution makes it possible to 3 times the grain crushing in a bunker by the working bodies of the threshing machine.

The Results of the Combine Design Adaptation to Work with a Stripper Header

Introduction. A decrease of damaging loose grains by threshing tools when combing standing plants is an urgent scientific problem. The aim of the research is to develop a technical solution and experimentally confirm the possibility of loose grains pre-separation from the stripped grain heap before it enters the threshing chamber of the combine harvester. Materials and Methods. The most promising technical solution to minimize the damaging of loose grain is an inclined chamber containing an oblong-hole lattice bottom, under which inclined augers are mounted. The experimental studies had two stages. In the first series of experiments, in laboratory conditions there were determined the optimal sizes of the lattice bottom holes to ensure the maximum passage of loose grains. In the second series of experiments, the degrees of separating and damaging loose grains were evaluated in real field conditions. Results. According to the results of laboratory studies, it was found that the maximum passage of loose grains through the holes of the lattice bottom is 68.7% with the width of holes 8 mm and their length 160 mm. According to the results of field experiments, it was found that the average passage of loose grains through the holes of the lattice bottom is 90%. At the same time, damaging grains in the inclined chamber did not exceed 0.5%, and in the hopper 1.75%. Damaging grains in the bunker was in the range of 5.25% when the combine operated without pre-separation of the combed grain heap on the lattice bottom of the inclined chamber. Discussion and Conclusion. Pre-separation of loose grains from the combed heap makes it possible to reduce damaging grains at least three times, and also reduces the power consumed by the drive of the threshing machine by 11–12%.

КАЧЕСТВО УБОРКИ СОИ ЗЕРНОУБОРОЧНЫМИ КОМБАЙНАМИ

The assessment of the quality of soybean harvesting by grain harvesters was carried out in the farms of the Central Black Earth region. Combine harvesters RSM 161, Acros 595Plus, KZS-1218A were selected as objects of observation. Combines worked with headers of three types. These are a conventional grain header, a lowcut modified header, and a stock soybean header. When working with a conventional grain header, soybean losses behind the header reached 12.6%. Large losses limit the use of conventional grain headers in soybean harvesting. The headers upgraded for a low cut had losses of 2.1 ... 2.4%. Serial domestic soybean headers "Float Stream" allowed losses of 4 ... 8% under the observed conditions. This was a loss in loose grain, no loss in uncut beans. The main reason for the increased losses is the harvesting of dry, overripe crops. In other conditions, these headers may well work on harvesting soybeans with losses acceptable by agro-requirements. Losses behind the thresher for the observed combines were in the range of 1.4 ... 4.0%. The increased losses of soybean grain behind the threshing machine were due to the high rotational speed of the cleaning fan. Light grain was simply blown out. Crushing of bunker grain of combines varied within 3.6…10%. High crushing was observed in combines with increased speed of the threshing drum and insufficient clearance between the drum and the deck. The clogging of bunker grain on the observed combines was in the range of 0.8 ... 2.7%. Combines with a cleaning fan speed of 800 rpm showed less contamination of about 1%, but at the same time, grain losses increased up to 4% behind the combine thresher. As a result, the decisive influence on losses during soybean harvesting was confirmed by the type of header and technological adjustments of the combine.

Foraging Behaviour of Some Syrphid Flies on Mango

This study in on the foraging behaviour of syrphid flies belonging to the tribes Eristalini (Eristalinus arvorum, E. quinquestriatus and Mesembrius quadrivittatus) and Syrphini (Episyrphus balteatus). The foraging activity, rate and speed, loose pollen grains and abundance were evaluated at Jorhat during 2018 and 2019 on mango flowers var. Amrapali. These revealed that the peak period of visit was 1 000-1200 hr. The relative abundance of the syrphids was maximum (8.90 ± 0.22/5 min) at 1100-1200 hr and (7.07 ± 0.51/5 min) at 1200-1300 hr; it was minimum (2.40 ± 0.17 and 2.49 ± 0.09/5min) at 0700-0800 hr, respectively. The loose pollen grains adhering to them ranged from 1294.80 ± 60.82 to 1415.80 ± 110.80/forager. The maximum pollination index of 12.52 was obtained with the Eristalini, while it was 8.14 in Syrphini (2018); in 2019, it was 9.63 and 7.14, respectively. These syrphids visited flowers during midday with more activity, foraging rate and foraging speed.

Interaction mechanics model for screw‐drive wheel of granary robot traveling on the loose grain terrain

AbstractThe screw drive mechanism has excellent driving performance on soft terrain and it is a good application for granary robot traveling on the loose grain surface. The investigation on screw drive wheel‐terrain contact mechanics is necessary to predict the traveling performance of the novel Screw‐Drive Granary Robot. Because the motion of grain particles is extremely complex beneath the wheel in the space, shearing displacement is decomposed into the longitudinal and tangential shearing displacement in this paper, and the corresponding shearing stress is calculated separately. Then the screw‐drive wheel‐terrain contact mechanics theory based on terramechanics is established by integrating the normal stress and shearing stress. Through driving experiments on corn‐terrain, the slip sinkage is determined and the sinkage modeling is modified simultaneously considering both vertical load and slip to improve the accuracy of prediction. And the calculated total resistance and the bulldozing resistance show that there is a linear proportional coefficient between them and slope of the line is 2.74 in this case. Finally, the improved mathematical model for screw‐drive wheel is proposed, the average error of predicted resistive torque is 15.72% and the mean error of drawbar pull is 16.2%.

Evaluation of ad/desorption dynamics of S-PEEK/Zeolite composite coatings by T-LTJ method

In this work, the adsorption/desorption kinetics of a consolidated bed, for adsorption heat pumps application, coated with a new composite adsorbent material based on SAPO-34 zeolite in a matrix of sulfonated poly(ether-ether-ketone) was investigated. The heat exchanger was coated by drop casting with a composite zeolite/polymer mixture containing 90 wt% of SAPO-34 powder. The adsorption/desorption kinetic was investigated using the Thermal Large Temperature Jump method and compared with the same heat exchanger filled with loose grains of SAPO-34. The coated heat exchanger exhibits very high specific cooling capacity with a very fast adsorption kinetic. The characteristic times were approximately 39% lower compared to zeolite grains filled adsorber. Analogously, the obtained maximum specific power value was 85% higher than that of the uncoated one.

Method for Determining Grain Losses Behind the Combine Header and Thresher During Soybean Harvesting

It was noted that in waterlogged soil conditions, the existing methods for assessing field grain losses when harvesting soybeans using low-cut headers are not always suitable. (Research purpose) To improve the methodology for assessing soybean losses during harvesting in the waterlogged soil conditions, using the possibility of sampling them separately behind the header and thresher of the combine. (Materials and methods) The methodological approach was based on: the impact of crop heterogeneity; the principle of adequate accuracy in loss assessment, regardless of soil conditions during harvesting; accessibility, simplicity and minimal labor intensity of the method; the possibility of differentiating grain losses behind the header to identify their main sources. Three main loss zones were identified and the characteristics of their sources were considered. The authors presented a scheme for applying square metal frames with a 1-meter side length on crops and on a harvested field area after the passage of the combine. The authors described the sequence of laboratory and field assessment and formulae for determining natural grain losses, losses behind the header and their types, soybean losses behind the thresher and total losses behind the combine. (Results and discussion) A methodology for soybean loss assessment was developed and tested during the trial of the Case IH AF6140 combine with a New Holland 740CF-30DD(SF) header. It was found out that this combine meets all the norms for soybean grain losses at a combine speed of 6 kilometers per hour. Loose grains were revealed to be the largest share of losses behind the header. To further mitigate losses, it was proposed to control the number of reel revolutions. (Conclusions) We have developed a technical approach and an algorithm for grain loss assessment with the use of rigid metal frames, which ensures high reliability, efficiency and lower labor intensity when considering losses and calculating actual and permissible (from biological yield) values for the specific and relative soybean losses behind a header and combine harvester as a whole.

Deep learning and machine learning neural network approaches for multi class leather texture defect classification and segmentation

Modern leather industries are focused on producing high quality leather products for sustaining the market competitiveness. However, various leather defects are introduced during various stages of manufacturing process such as material handling, tanning and dyeing. Manual inspection of leather surfaces is subjective and inconsistent in nature; hence machine vision systems have been widely adopted for the automated inspection of leather defects. It is necessary develop suitable image processing algorithms for localize leather defects such as folding marks, growth marks, grain off, loose grain, and pinhole due to the ambiguous texture pattern and tiny nature in the localized regions of the leather. This paper presents deep learning neural network-based approach for automatic localization and classification of leather defects using a machine vision system. In this work, popular convolutional neural networks are trained using leather images of different leather defects and a class activation mapping technique is followed to locate the region of interest for the class of leather defect. Convolution neural networks such as Google net, Squeeze-net, RestNet are found to provide better accuracy of classification as compared with the state-of-the-art neural network architectures and the results are presented.Graphical

СРАВНИТЕЛЬНАЯ ВЕТЕРИНАРНО-САНИТАРНАЯ ОЦЕНКА РАЗЛИЧНЫХ ПРЕПАРАТИВНЫХ ФОРМ РОДЕНТИЦИДНЫХ ПРИМАНОК, ПРИМЕНЯЕМЫХ В ЖИВОТНОВОДЧЕСКИХ ОБЪЕКТАХ

The article presents a comparative veterinary and sanitary assessment of various preparative forms of rodenticidal baits for the control of synanthropic (mouse-like) rodents. The rodenticidal activity of deratization agents in the form of loose grain bait, paper bags, mineral and gelatin capsules were studied in laboratory conditions. New knowledge about the bait consumption by grey rats depending on their shape has been obtained. The variety of forms of rodenticides makes it possible to select the formulations of baits taking into account production features, natural and climatic characteristics and the availability of food resources at livestock facilities, as well as increase the attractiveness of the bait, prevent pollution of environmental objects with anticoagulant poisons and exclude possible poisoning of non-target animal species.

Pollinator diversity and foraging behavior of Apis mellifera Linnaeus and Apis cerana Fabricius on Chinese cabbage (Brassica rapa Linnaeus subspecies chinensis) grown under different farming systems

The present study was on pollinator diversity and foraging behavior of Apis mellifera Linnaeus and Apis cerana Fabricius on Chinese cabbage (Brassica rapa Linnaeus subspecies chinensis) grown under different farming systems. A total of 19 insects belonging to 16 genera under 7 families and 3 orders were recorded on Chinese cabbage. Among all insect visitors, A. mellifera (8.85 / 100 flowers) was the most dominant visitor. Significantly higher abundance was recorded in SPNF system followed by the control and CF system, respectively. The insect pollinators showed a positive correlation with temperature and a negative correlation with humidity. The average number of flowers visited by both foragers in one minute was significantly more in SPNF system followed by the control and CF system. The average time spent per flower by both foragers was significantly more in the CF system followed by the control and SPNF system. The number of loose pollen grains sticking to the body of insect pollinators recorded in SPNF system and CF system was statistically the same. Hence, it can be concluded that pollinators prefer SPNF system as compared to CF system and control. So, due to enhanced pollination in SPNF system, farmers may obtain more yields if they are consistent with the timely application of indigenous farm products.

Study on magnetic preparation of dual disk based on silica gel magneto-elastic abrasive particles

Magneto-elastic abrasive grains have magnetism, low elastic modulus and excellent abrasive performance, and have the characteristics of bonded abrasive grains and loose abrasive grains. The dual-disk magnetic preparation greatly improves the preparation quality and efficiency. Firstly, the magneto-elastic abrasive particles are introduced into the edge preparation of the dual-disk magnetic tool, and the preparation method of 4035 silica gel magneto-elastic abrasive particles is proposed. According to the microscopic characteristics of the magneto-elastic abrasive particles, the finite element software ABAQUS is used to establish the magneto-elastic abrasive particles. The meso-level representative volume element (RVE) model is built to analyze the stress and strain law of magneto-elastic abrasive particles under tension and compression. Secondly, an experimental platform for magnetic preparation of magneto-elastic abrasive particles with dual disks was built to analyze the force of magneto-elastic abrasive particles. Finally, Through the magnetic preparation experiment of the magneto-elastic abrasive dual-disk magnetic force, the influence of the disk rotation speed, abrasive particle size and relative magnetic permeability on the cutting edge wear is studied. And compared to the magnetic abrasive particles double-disk magnetic and drag finishing method, the magneto-elastic abrasive particle double-disk magnetic preparation method can obtain the maximum edge wear amount and the maximum surface roughness decreasing amplitude. The research results are of great significance to promote the progress of our country's magnetic high-efficiency processing and magneto-finishing processing technology.

Liquefaction in Palu: the cause of massive mudflows

The 7.5 Mw tectonic earthquake that hit Palu City on 28 September 2018 was followed by tsunami and liquefaction, triggered massive mudflows in Balaroa, Petobo, and Jono Oge areas. This study focuses on the generating factors of liquefaction such as the condition of soil lithology, depth of water table, the distance to the focal mechanism, and the thickness of soft sediment. Microtremor data, including the Horizontal Vertical Spectral Ratio (HVSR), geological condition, and borehole data, were examined to conduct the liquefaction analysis. The analysis results based on the microtremor data showed that the distribution of ground shear strain values in Palu City ranged from 0.75 × 10–4 to 2.56 × 10–4. The distribution of the locations of the liquefaction was correlated to the distribution of ground shear strain values. High ground shear strain values and a shallow groundwater level were discovered in Palu City valley, which indicates that liquefaction in Palu City will undoubtedly occur. The semi-empirical method confirmed that Balaroa, Petobo, and Jono Oge had undergone large-scale liquefaction at a maximum depth of 16 m below the ground level. The average peak of water runoff that generated the mudflow was estimated to be at 11.31 cm3/s. Since the soil has loose soil grain with high water content, the soil will turn into a massive amount of mud during the liquefaction.

Effect of Produced Sand Particles and Fines on Scale Inhibitor: A Review

Application of scale inhibitors in oil and gas production is aimed at mitigating scale blockage during production. Many experimental, mathematical, and numerical simulation modeling works have been carried out to evaluate behavior, performance, and interaction of the scale inhibitor chemicals within porous media in relation to their efficiency in solving scale problem. However, the mechanisms underpinning scale inhibitors performance are not well published. Some research works have shown theoretically that not all scale inhibitors pumped into the formation adsorb onto the formation rock. Some of the inhibitors may adsorb on produced loose sand grains or colloidal fine sand particles which float and flow within the pore spaces along with the scale inhibitor mostly in unconsolidated reservoirs This paper provides a review of research work on the effect of produced loose sand or colloidal fine particles flow on polyphosphonates and polyphosphinopolymer scale inhibitors performances during crude production.

ПОДБОР РЕЖИМА ЗАТИРАНИЯ ПРИ ПРИГОТОВЛЕНИИ ПИВНОГО СУСЛА С ИСПОЛЬЗОВАНИЕМ ПШЕНИЧНОГО СОЛОДА

In recent years, according to the sharp increase in the number of breweries and high competition on the consumer market, it is very important to extend the raw material base of the industry and the range of produced beer from the recommended raw materials. One of the ways to expand the raw material base of breweries is developing recommendations for the use of new zoned varieties of barley, in particular as well as the use of special malts, wheat malt, the development of new recipes and technologies for beer producing. As it is known, barley, wheat, rye, and malt produced from these cereal crops are processed to a greater extent at present. Along with traditional types of cereals, such cereals as amaranth, buckwheat, triticale, sorghum, oats, etc. are used. Among the listed alternative crops, wheat should be noted as the most promising type of cereal raw materials. Wheat (Triticum) is an herbaceous annual plant of the cereal family. Hard wheat (T. durum) and soft wheat (T. aestivum) are the most important. Both species are holo-grain, i.e., the grain is covered with fruiting and seed shells, fused and consisting of several layers of cells, and do not have flower (chaff) shells. At present time, high-yielding winter and spring wheat (T.aestivum) is mainly cultivated. This species has loose floury grains and rather low protein content. It should be noted that unmalted wheat is rarely used in brewing. This is because that the use of this cereal as unmalted material leads to significant deviations in the technological process, in particular, the filtration of wort and beer slows down, reduces the colloidal stability of the final product. At the same time, as a raw material for malt, wheat has some advantages over barley. The article deals with the effect of different amounts of wheat malt on the mashing process, the percentage of mashing and mashing modes of barley and wheat malt are selected experimentally.

Study on Microstructure and Properties of Aeronautical Nickel-Based Superalloy in Laser Directional Solidification

FFor the directional solidification repair of blade damage in an aviation turbine, a directional-growth repair layer on the surface of a nickel-based superalloy was prepared using an Nd:YAG laser. The microstructure of the directional-growth repair layer was investigated using scanning electron microscopy and transmission electron microscopy. Its phase composition and corrosion resistance were also analyzed and tested. The results indicate that the grains in the repair zone solidified in the same direction as the substrate and formed continuous columnar crystals, which were arranged in an orderly manner. A small number of secondary dendritic cells were dispersed in the transverse direction of the columnar crystals. The phase composition was mainly composed of the α′-based phase, β-precipitated strengthening phase, MC carbide, and interdendritic α′/β eutectic phase. The corrosion kinetic curve of the repair zone changed linearly. The oxide film was uniform and dense, and was mainly composed of continuous granular oxide. The corrosion kinetic curve of the substrate conformed to the parabolic law. The oxide film was composed of loose and bulky granular grains, which were stacked in the shape of regular polyhedra and distributed in the form of an island.

On the Influence of Microtopography on the Sliding Performance of Cross Country Skis

The sliding performance of cross country skis is mainly influenced by the ability of the ski base to minimize capillary forces and contact area. Whereas, the first condition depends on hydrophobicity, the second one is controlled by the ski grinding structure and the morphology of snow. In this contribution the results of sliding tests with five typical grinding structures will be presented and compared to calculations of the real area of contact. Surface topographies were measured and corresponding roughness features were analyzed by 3D optical microscopy. The measured ski base profiles and the measured grain size distribution of granular snow at −2°C were employed within a bearing model for a rough surface in contact with loose and freely-moving snow grains treated as ice spheres. For the five grinding structures, this model revealed a good correlation of the real area of contact between ski and snow with run times in lab-condition sliding tests. The results indicate that the snow-containing volume of the grinding structure is pivotal for tailoring the sliding behavior.

Zeolite NaY-Copper Composites Produced by Sintering Processes for Adsorption Heat Transformation—Technology, Structure and Performance

In adsorption heat pumps, the adsorbent is typically combined with heat conducting structures in order to ensure high power output. A new approach for the direct integration of zeolite granules into a copper structure made of short copper fibers is presented here. Zeolite NaY granules with two different grain sizes are coated with copper fibers and powder and sintered to larger structures. The sorption dynamics of these structures were measured and evaluated in terms of heat and mass transfer resistances and compared to the loose grain configuration of the same material. We found that the thermal conductivity of such a composite structure is approximately 10 times higher than the thermal conductivity of an adsorbent bed with NaY granules. Sorption equilibrium measurements with a volumetric method indicate that the maximum uptake is not altered by the manufacturing process. Furthermore, the impact of the adsorbent–metal structure on the total thermal mass of an adsorption heat exchanger is evaluated. The price of the superior thermal conductivity is a 40% higher thermal mass of the adsorption heat exchanger compared to the loose grain configuration.