Production Of Flakes Research Articles

Electrochemical Studies on CO2 Reduction at Liquid Gainsn Alloy Electrodes

The electrochemical reduction of CO2 (CO2RR) offers a sustainable technology for converting CO2 into valuable products when using electricity generated from renewable sources. Application-oriented research is currently focused mainly on the electrolysis of CO2 to hydrogen-rich fuels or chemical feedstock materials. In contrast our project aims to form solid carbon or carbon rich products (e.g. oxalate), which can finally be disposed in geological repositories. This negative emission technology is developed for a long-term and thereby sustainable CO2 removal from the global CO2 cycle 1. The continuous electrochemical formation of solid carbon from CO2 has so far only been reported on liquid GaInSn-M alloys (M: Ce, V) in water-containing DMF 2,3. Liquid electrodes have the advantage over solid electrodes that solid products do not adhere at the interface and therefore deactivate the catalytic properties of the electrode (coking effect). In first experiments, we studied GaInSn without additional metal alloying in DMF/H2O/ TBAPF6 electrolyte and got differing results to the previously published data. In our experiments, even pure GaInSn shows a significant activity for CO2RR to carbon monoxide and formic acid accompanied by lower quantities of H2. The product distribution (faradaic efficiencies) depends strongly on the water content in the DMF electrolyte. The production rate of CO increases significantly even with small amounts of water. First DFT simulations of the CO2RR provide possible explanations of this effect. Furthermore, it was observed that, depending on the applied cathodic potential, metallic nano particles are released from the GaInSn surface into the organic electrolyte (expulsion effect) which indicates a possible change in the surface composition during CO2 electrolysis 4. In accordance with the literature, our findings confirm the production of carbon flakes from CO2 on cerium modified GaInSn. However, we observe it even independently from the addition of water to the DMF electrolyte. DFT calculations enable us to conclude that the high affinity of cerium to oxygen is responsible for the change in product selectivity, as it can extract oxygen from CO2.1: May, M. M. and Rehfeld, Earth Syst. Dynam., 10, 1–7.doi.org/10.5194/esd-10-1-2019, 2019.2: Dorna Esrafilzadeh, NATURE COMMUNICATIONS | (2019) 10:865.doi.org/10.1038/s41467-019-08824-83: Mehmood Irfan, J. Mat. Chem. A, Issue 27, 2023doi.org/10.1039/D3TA01379K4: Mahroo Baharfar, Chemistry of Materials 2022 34 (23), 10761-10771doi.org/10.1038/s41467-019-08824-8 Figure 1

Liquid-Phase Fabrication of Janus 2D Materials: Defect-Rich MoS2 Ultrathin Layers Asymmetrically Decorated with Au Nanoparticles.

Asymmetrically decorated nanoparticles (NPs), also known as "Janus nanoparticles", possess at least two differently functionalized surfaces. This coexistence results in novel features that surpass the inherited benefits of the initial counterparts. Despite significant advances in spherical morphologies, research on Janus two-dimensional (2D) materials is limited, as fabrication strategies primarily focus on dry deposition techniques. To produce Janus 2D materials in large quantities, solution-based techniques are proposed. However, this approach remains largely unexplored for 2D materials other than graphene and its derivatives, and it yields Janus 2D materials in very low amounts. This study develops a liquid-phase fabrication strategy for the asymmetric decoration of MoS2 ultrathin layers with gold nanoparticles. This approach builds on previous advances in the asymmetric functionalization of spherical nanoparticles, using SiO2 microbeads as a masking template. Interestingly, the photoluminescence (PL) spectrum of the processed material is unusually dominated by the B exciton emission. The reported versatile method has proven to be scalable, enabling the production of 2D Janus flakes in appreciable quantities, whether as 1T or 2H-polytypes. Overall, the novel synthetic strategy is highly adaptable and can be extended to a variety of other 2D materials and functionalizing agents.

Accelerating Optimal Synthesis of Atomically Thin MoS2: A Constrained Bayesian Optimization Guided Brachistochrone Approach

AbstractA machine learning (ML) guided approach is presented for the accelerated optimization of chemical vapor deposition (CVD) synthesis of 2D materials toward the highest quality, starting from low‐quality or unsuccessful synthesis conditions. Using 26 sets of these synthesis conditions as the initial training dataset, our method systematically guides experimental synthesis towards optoelectronic‐grade monolayer MoS2 flakes. A‐exciton linewidth (σA) as narrow as 38 meV could be achieved in 2D MoS2 flakes after only an additional 35 trials (reflecting 15% of the full factorial design dataset for training purposes). In practical terms, this reflects a decrease of the possible experimental time to optimize the parameters from up to one year to about two months. This remarkable efficiency was achieved by formulating a constrained sequencing optimization problem solved via a combination of constraint learning and Bayesian Optimization with the narrowness of σA as the single target metric. By employing graph‐based semi‐supervised learning with data acquired through a multi‐criteria sampling method, the constraint model effectively delineates and refines the feasible design space for monolayer flake production. Additionally, the Gaussian Process regression effectively captures the relationships between synthesis parameters and outcomes, offering high predictive capability along with a measure of prediction uncertainty. This method is scalable to a higher number of synthesis parameters and target metrics and is transferrable to other materials and types of reactors. This study envisions that this method will be fundamental for CVD and similar techniques in the future.

Experimental comparison of the effects of the two designed probes for exfoliation of graphene by sonication.

In the present research, comparative simulation and experimental investigation were carried out for two different probes to improve the efficiency and quality of few-layer graphene utilizing liquid-phase exfoliation. Two differently designed shaped probes are fabricated for this study, i.e., a simple probe and a stepped probe. The acoustic pressure distribution in the vessel is simulated for both probes at different output powers. In the experiment, both probes exfoliate graphite powder in a mixture of deionized water and ethanol. Different sonication times and output power were studied for different pulse modes. The graphene layers were characterized using Ultraviolet-visible spectroscopy (UV‒Vis), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Raman Microscope. The simulation shows that the total displacement on the tip of the stepped probe is 5.7% greater than that of the simple probe. Also, the pressure difference produced by the stepped probe is 9.15 × 106 pa compared to the pressure difference of the simple probe which is 8.23 × 106 pa. Consequently, the stepped probe was more effective in exfoliating graphene. The experimental results show that the absorbance peak in the stepped probe is approximately 32% greater than the absorbance peak in the simple probe with the same output power. Also, the graphene with better quality is produced with the stepped probe compared to the simple probe, which verifies the simulation findings. Additionally, the optimum output power, pulse duration, and sonication time to produce graphene with less time and energy consumption are obtained. The best graphene flakes were obtained via sonication with a pulse duration of 0.7 s, an output power of 282 W, and a sonication time of 45 min using a stepped probe. UV-Vis., SEM and TEM analysis show increases in quantity and quality of the exfoliated flakes. These results are approved by the peak ratio of I2D/IG around 1 in Raman spectra revealed the production of the few-layer graphene by the simple probe and the bilayer graphene by the stepped probe. So, this method is suitable for the production of graphene flakes from graphite in suitable quantity and quality.

The emergence of large flake-based Acheulian technology: perspective from the highland site-complex of Melka Wakena, Ethiopia

Isaac GL (1969) proposed that Large Cutting Tools (LCTs) made on large flake blanks detached from giant/boulder cores are the key technological variable that distinguishes the Acheulian from the Oldowan. The production of large flake blanks was initially observed in the earliest records of the Acheulian technology in Africa ca. 1.75 Ma, subsequently becoming a technological feature of many sites across eastern Africa. Still, the mode and tempo of evolution of the large flake-based Acheulian technology remains poorly understood. Here we report on the large flake-based Acheulian assemblage at locality MW5 in the Melka Wakena site-complex, chronologically constrained between 1.37 and 1.34 Ma. At the site-complex level we note that aspects related to small flake production remain relatively unchanged since ~ 1.6 Ma. Secondary modification of small flakes by retouch remained marginal and there is only a slight increase in the frequency of structured reduction of cores, compared to the earlier 1.6 Ma assemblage. In contrast, the MW5 lithic assemblages inform of the diachronic shift of lithic techno-economy into a large flake-based LCTs technology. This shift is characterized by: (1) A highly selective use of a specific raw material (glassy ignimbrite) for the production of large flake blanks; (2) transport of prepared large flake blanks from relatively distant sources into the sites as part of a spatially and temporally fragmented reduction sequence; (3) improved know-how of large flake production, (4) the introduction of the Kombewa technology; (5) a unified technological concept for the production of handaxes and cleavers, diverging only in the specific decisions determining their final shape parameters. Taken together, these trends indicate changes in techno-economic strategies related to LCT production, including higher levels of pre-planning in the raw material acquisition stage and higher investment in controlling the morphometric properties of the artifacts.

Assessing the Role of Early “Large Cutting Tools” in Flake Production: an Experimental Comparison of Early Acheulean Handaxe and Oldowan Core Manufacture

ABSTRACT The Acheulean has long been defined by its characteristic large bifacial implements (“Large Cutting Tools”), which appear from its very beginning. While experimental work attests to the usefulness of these tools in heavy-duty cutting tasks, the morphology of these experimental tools is often very different to Early Acheulean forms, with use-wear confirmation of their deployment at this time extremely patchy. This leaves open the potential for other explanations of biface innovation, including that they evolved as a specialized core form. Here, a dedicated methodology for the comparison of Oldowan-like cores and Early Acheulean-like bifaces is presented, alongside a preliminary analysis of changes to core morphology throughout the knapping process. The results highlight some key differences in the metric variables under consideration, that may have implications for later analysis of flake morphology. This paper also serves to discuss potential limitations of the method that could be addressed in future replications.

An Actualistic Experimental Study of Giant Quartzite Core Reduction Strategies: Implications for Large Flake Blank Production and Handaxe Manufacture at Amanzi Springs, South Africa

ABSTRACT The later Acheulian assemblages (ca. 534–< 390 ka) from Amanzi Springs in South Africa show a preferential selection for large flake blanks when undertaking large cutting tool manufacture. However, due to the small number of giant cores from the site, we have limited insight into the technical preparation of quartzite raw material packages for large flake production. Here, we present an actualistic experimental study to better understand these procedures at the site and to gain perspective on how knappers may have reduced quartzite boulders of differing internal qualities. Our results highlight the influence of raw material constraints and how the overall morphology of quartzite boulders in turn impacts giant core reduction sequences and large flake blank morphologies. Finally, the experimental study exemplifies the need for high levels of knapping expertise to deal with tough, heterogeneous quartzite varieties.

Beyond Large-Shaped Tools: Technological Innovations and Continuities at the Late Early Pleistocene Assemblage of El Barranc de la Boella (Tarragona, Spain)

The emergence of the mode 2 technocomplex, traditionally characterized by the development of large cutting tools (LCTs) or standardized large-shaped tools, has also implied a range of new technological behaviours. These include enhanced raw material management, more sophisticated knapping strategies, and transport patterns, among other innovations. Unit II of the localities of La Mina, El Forn, and Pit 1 in El Barranc de la Boella (Tarragona, Spain) — dating back to between 0.99–0.78 million years ago — contains the oldest mode 2 assemblages in the European subcontinent and represents an exceptional opportunity to examine the technological features associated with the appearance of LCTs in Europe and to provide clues to shed light to different hypotheses about their appearance. The presence of functionally diverse but environmentally similar localities enables a study of behavioural flexibility and technological variation, marking a critical contribution to understanding early human technological evolution. Our research focuses on the technological behaviours of hominins in unit II of Pit 1, La Mina, and El Forn at Barranc de la Boella, examining five keys technological aspects such as (1) raw material management, (2) core reduction sequences, (3) reduction intensity, (4) large flake production, and (5) the spatiotemporal integrity of reduction sequences. We compare these behaviours with those observed in mode 1 (~ 1.8–0.9 Ma) and early Middle Pleistocene (~ 0.78–0.6 Ma) assemblages across western Europe. Our findings reveal significant advancements and anticipatory behaviours at El Barranc de la Boella, such as the use of procedural templates for core reduction strategies and the production of large-shaped tools governed by principles of gestural economy, and also the existence of different reduction sequences in different raw materials according to specific purposes. The technological behaviours observed at El Barranc de la Boella seem to be more indicative of population dispersals rather than local evolutionary developments from mode 1 technologies. The non-linear evolution of core knapping strategies, along with the variability in large-shaped tool types, suggests multiple waves of hominin dispersals into Europe during this crucial period. We propose that El Barranc de la Boella may represent an early dispersal of the Acheulean from Africa around 1.4 million years ago, potentially connected to assemblages such as ‘Ubeidiya. This study underscores the complexity of lithic technology during this period and contributes significantly to our understanding of the complex emergence and adoption of new technological behaviours in European early mode 2 assemblages, extending beyond the mere appearance of LCTs.

When is a handaxe a planned-axe? exploring morphological variability in the Acheulean.

The handaxe is an iconic stone tool form used to define and symbolise both the Acheulean and the wider Palaeolithic. There has long been debate around the extent of its morphological variability between sites, and the role that extrinsic factors (especially raw material, blank type, and the extent of resharpening) have played in driving this variability, but there has been a lack of high-resolution examinations of these factors in the same study. In this paper, we present a 2D geometric morphometric analysis of 1097 handaxes from across Africa, the Levant, and western Europe to examine the patterning of this variability and what it can tell us about hominin behaviour. We replicate the findings of previous studies, that handaxe shape varies significantly between sites and entire continental regions, but we find no evidence for raw material, blank type, or resharpening in determining this pattern. What we do find, however, is that markers of reduction trajectory vary substantially between sites, suggesting that handaxes were deployed differently according to hominin need at a given site. We argue this is reflective of a continuum of reduction strategies, from those focused on the maintenance of a sharp cutting edge (i.e. direct use in cutting activities), to those focused on maintaining tip shapes, and perhaps a corresponding production of flakes. Implications for hominin behavioural flexibility are discussed.

Raw Materials and Lithic Production During the Early Magdalenian in Cantabrian Spain: Cova Rosa (Ribadesella, Asturias)

The lithic assemblage studied here comes from Cova Rosa, one of the main Upper Palaeolithic sites in Asturias (northern Spain). The remains were found in Layer B5, which was excavated by F. Jordá Cerdá and A. Gómez Fuentes in 1978 and are associated with an osseous assemblage and archaeozoological remains. This occupation has been dated by radiocarbon to about 16,400 BP (ca. 19.8–19.6 ka cal BP), corresponding to Archaic/Lower Magdalenian. The present study combines the determination of the raw materials and the identification of the production systems to achieve an understanding of the management of lithic resources by hunter-gatherer groups in the Late Pleistocene. The sourcing of mostly local materials (mainly Piloña flint), the wide variety of rock types of diverse provenances (up to 10 types), and the presence of well-represented lithological tracers (Flysch, Chalosse) turn Cova Rosa into an important case for studying different lithic raw material procurement models. The predominance of microlaminar production and the variability in the exploitation strategies used to obtain backed tools, as well as the poor standardisation of flake production, follow the dynamics observed in other occupations of similar chronology in a wide geographical area that includes Cantabrian Spain and south-west France.

Newly discovered stone age site of Ulaan khanan :

The Kherlen River, which headwaters from the mountains of Khan Khentii, streams through the territory of three provinces of Mongolia: Khentii, Tuv, and Dornod. Most of the archaeological sites found in its basin exhibit characteristics of the Neolithic period, and mainly consist of in situ stone tools dispersed on the surface. The mixing of prehistoric artifacts from different periods in a certain place is undoubtedly related to the unique climatic conditions of Mongolia and the geology of the Kherlen River basin. In this article, we discuss the site of Ulaan Khanan, located about 21 km south of the Kherlen River in the Bayankhutag soum area of Khentii Province. The stone artifacts from this site are suggested as belonging to two different periods: The Paleolithic and Neolithic. The Paleolithic artifacts include points, scrapers, retouched blades, and different types of lithic blanks (mainly blades and flakes). Conversely, the Neolithic artifacts conform to knapping methods involving the reduction of narrow-faced and wedge-shaped cores, including a single micro-core as well as polyhedral and cylindrical cores. The lithic assemblage(s) described here consists of a few tool types, such as points, scrapers, burins, combination tools, and retouched blades, and show evidence of reduction sequences primarily aimed at blade and flake production.

Production of Mg thin flakes with enhanced hydrogen storage performance

Flake-like particles are interesting materials for the preparation of alloys and homogeneous nanocomposites, they also have potential use as hydrogen storage materials. However, limited information is available regarding the synthesis of pure magnesium with flake-like morphology. In this study, the successful production of Mg flakes was conducted using a cost-effective and simple method, such as high energy ball milling. Various milling parameters, including different milling times and process control agents, were tested. Optimal conditions led to the formation of coarse flakes with ∼1.72 μm thickness, while a two-step milling process produced thinner flakes with submicron thickness (∼242 nm). Ductilization of the material and a significant reduction in crystal size during the milling process were observed via X-ray diffraction. Isothermal kinetic tests at 350 °C and 20 bar revealed improved hydrogen storage performance for both coarse and thin flakes compared to pristine Mg. Coarse flakes achieved capacities of 4.1 wt% in 60 min while thin flakes reached 4.6 wt% in 6 min, compared to 3.4 wt% achieved in 100 min by pristine Mg. The improved behavior of thin flake-shaped Mg was maintained at 300 °C and 20 bar, with 4.5 wt% of hydrogen absorbed in 6 min. Even at lower testing pressures (10 bar) higher capacities were achieved at the expense of slower kinetics. These findings suggest that thin flake-shaped Mg is a suitable material with enhanced performance for hydrogen storage applications.

Phenomenon of Early Upper Palaeolithic Bladelet Assemblages in the Altai Mountains

Purpose. The present study is devoted to the analysis, systematization, verification and generalization of data on “Aurignacian-like” bladelet assemblages of the Early Upper Palaeolithic of the Altai. In the regional context, this luminous phenomenon is considered the main component of the technocomplex of the Ust-Karakolian cultural tradition and even a cultural marker.Results. The study was based on the analysis of archaeological material from known Early Upper Palaeolithic sites in the region, published and archival data containing information on the chronology, stratigraphy and planography of the industries. As a result, the data on the bladelet component of the Ust-Karakolian complexes from Altai, their industrial and spatial contexts have been updated and supplemented. Materials from the Ust-Karakol-1 (excavation 1, horizon B) and Anui-2 (excavation 2, horizon B) sites were found to be the reference for preservation and information of this industrial group. In both cases, the bladelet strategy dominates the assemblage, clearly standing out against the back-ground of non-specialized blade and flake production. The age of the industry was determined to be around 37–34 thousand cal. BP using previously published and new radiocarbon dating data.Conclusion. According to the obtained data, the main problems of identification and research of the Ust-Karakolian sites in Altai are related to the peculiarities of the conditions of their formation. They were determined by the processes of active slope formation, which led to deformation, fragmentation or complete destruction of the original archaeological structures.

Sustainable graphene production for solution-processed microsupercapacitors and multipurpose flexible electronics

The growing demand for portable and wearable electronics, Internet of Things microdevices, and wireless sensor networks has led to the development of miniaturized energy storage devices, such as microsupercapacitors (mSCs). With excellent electrical conductivity and high surface area in a layered structure, graphene materials are ideal for mSCs, but current manufacturing methods still hinder their widespread integration. Here, we propose a sustainable approach for the rapid and eco-friendly production of few-layer graphene flakes based on the exfoliation of graphite in water by a combination of high-shear mixing and a high-pressure airless spray. An all-carbon composite paste with high electrical conductivity and tunable viscosity was designed to fabricate planar, interdigitated mSCs on polyethylene terephthalate (PET). The flexible, metal-free mSCs achieved a Coulombic efficiency close to 100%, with areal and volumetric capacitances of 6.16 mF cm−2 and 2.46 F cm−3, respectively. The maximum energy density exceeds 200 μWh cm−3 with 91.5% capacitance retention after 10000 galvanostatic chargedischarge cycles. The mSCs retain the same performance when subjected to a wide bending range and can be easily modularized to adjust the voltage and capacitance outputs. Finally, high-performance coatings for electromagnetic interference shielding and wearable strain sensors are also fabricated to demonstrate the multipurpose applicability of the graphene-based paste.

Millukmungee 1: Stone artefacts and occupation at the junction of the Buchan and Snowy Rivers, GunaiKurnai Country, East Gippsland (Victoria, Australia)

Recent excavations at Millukmungee 1, a limestone rock shelter along the upper bank of the Buchan River in GunaiKurnai Country (southeastern Australia), uncovered archaeological evidence of Mid- to Late Holocene occupation spanning c. 5000 years. Here we report on the stone artefacts and faunal remains, especially in light of a paucity of published details on artefact types and technologies for this part of southeast Australia. Results indicate that this part of the site was occupied only rarely from 5590–5050 cal BP (the uncertainty range for the oldest artefact from the excavation) to 2340–2030 cal BP. During this period, most of the artefacts were made from silcrete, quartz, chert, and quartzite. Small backed artefacts are present during this phase, all dating between 4570–1940 cal BP. A single, much larger backed artefact (elouera) dates to later, ≤290 cal BP. After 1960 cal BP, activities focussed on the production of flakes from locally available quartz and, to a lesser extent, hornfels; large pebbles obtained from the nearby Buchan River channel were flaked during this period. Occupation ceased with the onset of settler colonialism in the mid-1800s CE.

Adaptions of hunter-gatherers before Younger Dryas in Gobi Desert, northwest China: Flexible technological strategies in Pigeon Mountain Locality 10

The role of Oasis-based economies was pivotal for Hunter-gatherers in the Gobi Desert following the Last Glacial Maximum. Despite this significance, there has been a lack of systematic technological studies on lithic assemblages to investigate the technological strategies employed by hunter-gatherers for desert adaptation. In this study, we conducted a lithic analysis based on new excavations at Pigeon Mountain Locality 10 (QG10), focusing on archaeological remains from CL3 and CL2 dating back to 13.7–11.7 ka cal BP. Our findings reveal that the lithic technology employed reflects a flexible strategy, characterized by expedient flake production, the versatility of flake cores, and a diverse array of microblade cores and tools. Notably, we observed an expedient organizational strategy in microblade production, involving minimal investment in pre-shaping microblade cores and reduced depletion in core rejuvenation. Additionally, there was a heightened use of local quartzite raw materials, indicating enhanced flexibility, possibly influenced by the relatively dry and cold environmental changes during that period.

PHYSICAL CHARACTERISTICS OF KEPOK BANANA BUD (Musa paradisiaca Linn.) FLAKES WITH VARIATIONS OF MOCAF FLOUR

Yellow Kepok banana buds (KBB) are well-known for their high dietary fiber content and prospective use as functional food additives. High fiber consumption has been linked to diabetes prevention. The production of flakes derived from KBB has the potential to facilitate individuals in incorporating high-fiber food items into their daily diets. Nevertheless, the utilization of just Yellow KBB flour yields flakes that are deemed undesirable by consumers due to their firm consistency and deep hue. The substitution of Yellow KBB flour with a combination of wheat flour and mocaf has the potential to enhance the physical characteristics of the resulting flakes. The objective of this study is to assess the physical attributes of flakes derived from KBB. This particular flake was produced using a series of five distinct formulations. The present study employed a completely randomized design (CRD) with three replications. The formulas consist the proportions of wheat flour (WF), mocaf flour (MF), and Yellow Kepok banana bud (KBB). The following are the five ratios: (100%:0%:0%), (50%:50%:0%), (50%:37.5%:12.5%), (50%:25%:25%), and (50%:37.5%:12.5%). The water absorption, swelling ability, texture, and color of flakes produced from wheat, mocaf, and KBB flour were examined. The F2 sample, consisting of a composition of 50% wheat flour, 37.5% mocaf flour, and 12.5% yellow KBB flour, exhibited the highest water absorption value (63.19%) among all the samples. In addition to this, F2 can be characterized as a specimen exhibiting a relatively low level of hardness (1.63 N) and a correspondingly low fracture value (2.08 N). The F2 flakes had a much higher brightness value (37.06) in comparison to the other samples used yellow KBB flour.

Efficient simulation of bitter gourd drying in active solar dryer: A state-of-the-art model

Greenhouse drying system is used to dry agricultural products or low-temperature thermal drying using a greenhouse structure. In this paper, an experimental and simulation study is carried out to evaluate the drying performances of an active solar greenhouse dryer using COMSOL Multiphysics. The experimental setup includes a compact thermal storage-based greenhouse dryer (1.5 m × 1.0 m x 0.5 m) equipped with a black gravel-covered Aluminium jacket and 35 kg of paraffin wax for heat retention which is located on the floor of the dryer. The experiments were conducted in Ranchi, India (23.34 °N, 85.30 °E) under clear sky conditions in the month of May. The amount of solar radiation (global solar radiation) varied from (630 W/m2 to 1052 W/m2) with an average of 936 W/m2, ambient air temperature (30.2 °C–38.2 °C), air relative humidity (31.6 %–34.6 %), and wind speed (0.9–1.0 m/s). The inside dryer temperature, humidity, wind speed, and floor temperature were also measured every hour. The average values of these parameters were 59.1 °C, 30.2 %, 0.91 m/s, and 69.1 °C, respectively. The FE (finite element) modelling finds out the maximum temperature in drying products, floor and dryer's outlet is 55.3 °C,72.4 °C and 67.4 °C, respectively at 13:00 h. The proposed dryer costs 19633.50 INR with an embodied energy of 1358.01 kW h. The proposed dryer has a break-even period of 1.87 years, and its lifespan is 35 years. During this time, the net CO2 emission was found to be 21.45 tonnes, and the earned carbon credit varies from 1505.01 to 30030.00 INR. The result shows that the drying efficiency is 42.52 %, reducing the initial moisture content from 88.64 % to 2.28 % within five consecutive hours. The energy and exergy efficiencies of the dryer are found to be 61.84 % and 56 % respectively. The system is a viable, sustainable choice for the large-scale production of bitter gourd flakes.

First Assessment of a Pebble Tool Industry in the Pesqueiro River Valley, Upper Uruguay River Basin, Southern Brazil

Abstract This article presents the first findings of a topographic survey plotting the location of archaeological material and of a technological study of the lithic industry at the SC-CHA-030 open-air archaeological site along the Pesqueiro riverbank, located in the upper course of the Uruguay River Basin in southwestern Brazil. We analyzed raw material selection and the production of shaped/façonnage tools (unifacial, bifacial, and trihedral) associated with the production (debitage) of cortical and semi-cortical flakes that were then transformed into tools by simple retouch. From the geoarchaeological point of view, the spatial distribution pattern of the material is meaningful in the context of the geomorphic transition between foothills and alluvial plain. Our study of technological behavior and the formation of archaeological sites finds that raw material and shaped pebble tools are a crucial aspect of the industries on the Paraná Basaltic Plateau of southern Brazil.

Intensive processing reduces quality of grains: a triangulation of three assessment methods

ABSTRACT The presented study evaluated different manufacturing procedures of breakfast cereals in view of their ability to preserve the natural quality of the raw material, as this is recommended by the EU Regulation 2018/848 for organic farming and the Demeter guidelines. From four crops (spelt, buckwheat, rice and quinoa), different products were manufactured: flakes, roasted flakes from cooked grains, extrudates from dough, and puffed grains. The samples (in total n = 18) were analysed for positive (thiamine, folate, lysine) and negative (acrylamide) health-related constituents, delayed fluorescence by Fluorescence Excitation Spectroscopy (FES) and food-induced emotions by the EmpathicFoodTest (EFT). The results showed that the four crops reacted similarly to the manufacturing processes, but the sensitivity of the crop was different for the health-related constituents, with spelt and rice showing greater sensitivity with respect to acrylamide formation and thiamine loss, than buckwheat and quinoa (though differences at the individual crop level were not statistically verified). The different assessment methods led to largely consistent evaluations of the processing methods: after extrusion, puffing and roasting flakes, significant quality losses were observed. Depending on the parameter of the test method, the classification of the degradation due to processing differed slightly: lysine degradation was significantly higher in puffed products (especially in rice and spelt) and acrylamide concentration was high (> 200 µg kg-1) in roasted and puffed spelt. The methods EFT and FES rated extruded samples particularly unfavourably. The least harmful process in all parameters was the production of flakes.