Inorganic Residues Research Articles

Mechanical Characterization of Home Compostable Biopolymer Composites Reinforced with Organic and Inorganic Residues for Single-Use Plastics

Mechanical Characterization of Home Compostable Biopolymer Composites Reinforced with Organic and Inorganic Residues for Single-Use Plastics

Optimized Border Irrigation Improved Nitrogen Accumulation, Translocation of Winter Wheat and Reduce Soil Nitrate Nitrogen Residue

We aimed to optimize field border length in the Huang-Huai-Hai Plain of China (HPC) to reduce soil inorganic nitrogen residues and increase nitrogen absorption and utilization by wheat plants using a traditional border irrigation system. In a two-year experiment (2017–2019) conducted in the HPC, four border lengths were tested: 20 m (L20), 30 m (L30), 40 m (L40), and 50 m (L50). Supplementary irrigation was implemented during jointing and anthesis stages, and control fields received treatment without irrigation. The results showed that, compared with irrigation of other border lengths, L40 irrigation significantly increased nitrogen transport in stems and leaves. In addition, L40 irrigation had the highest rate of grain nitrogen accumulation after anthesis. The risk of nitrate leaching to deep layers increased with increasing border length; however, L40 irrigation improved the plants’ capacity to absorb soil nitrogen, and the soil inorganic nitrogen residue was significantly lower than that with irrigation of other border lengths. Therefore, the grain yield and nitrogen fertilizer utilization under L40 irrigation were significantly higher than those under irrigation of other border lengths, and L40 was considered as the best border irrigation length.

Технологии и оборудование для плазменной утилизации медицинских отходов

В технологии переработки медицинских отходов, в том числе отходов, образующихся во время пандемии, основными общепринятыми способами являются термические, с использованием топливных или плазменных печей, для сжигания в кислородсодержащей среде или для пиролиза в восстановительной атмосфере с получением синтез-газа (H2 и CO), которые в дальнейшем можно использовать в химической промышленности или в качестве топлива. При этом непосредственное сжигание или пиролиз исходных твердых отходов, обеспечивающие газификацию их органических компонентов, обычно является лишь первой стадией общего технологического процесса. В целом он состоит из трех этапов. На втором этапе доводят до заданного состава газообразные продукты первого этапа, на третьем этапе обезвреживают неорганический остаток – золу, образование которой составляет до 20% несортированных медицинских отходов. Перспективным вариантом рассматриваемой технологии является использование электродуговых плазменных установок. По сравнению с неплазменными печами, даже использующими интенсивные газодинамические режимы работы, достигается ряд существенных преимуществ: уменьшение объема печи (при сохранении производительности сырья) и уменьшение объема уходящих газов примерно на порядок при повышении температуры в реакционной зоне печи до 2000–2300 °С.

Comparison Between Different Composite Resins Used for Clear Aligner Attachments: An In-Vitro Study

Attachments are specific features of clear aligner treatment designed to ensure the aligner’s retention and the predictability of tooth movements. The properties of composite resin used for their reproduction play a relevant role to preserve their integrity and shape over the time. Thus, the aim of the present evaluation was to compare the mechanical properties and the wear performance of two nanocomposite by means of mechanical and tribological tests. Twelve samples for both flowable nanocomposite (FNC) and conventional nanocomposite (CNC) were created. The two nanocomposites differ in terms of filler volume and viscosity of the mixture. The following tests were performed: thermal analysis and burning test; flat instrumented indentation test and a compression stress relaxation test; tribological analysis. Wear evaluation was performed by means of a contact probe surface profiler and a TayMap software for the 3D analysis. A customized step-sliding test was conducted to simulate the clinical application of materials with a polymethyl methacrylate (PMMA) ball used as counterpart. Wear evaluation of both resin surfaces and PMMA ball was performed. No differences were found in terms of polymeric nature and quantity of nanoparticles in the matrix. FNC showed lower density values (1.62 g/cm3 ± 0.02) and inorganic percentage residue (41%) than the CNC (respectively 1.95 g/cm3 ± 0.01 and 23%). Significant differences in terms of decrement of stress values, elastic modulus (1,114.12 ± 91.39 MPa), and stress relaxation rate (24.39% ± 3.23) were observed for the CNC when compared to the FNC (respectively, 835.04 ± 184.73 MPa and 40.19% ± 4.65). FNC showed higher values of dynamic friction coefficient (0.72 ± 0.017) and more worn and deeper profiles than the conventional ones. The step-sliding test with a PMMA ball confirmed a higher friction coefficient for FNC and a greater wear of the PMMA surfaces when used against flowable samples. Lower viscosity of FNC ensures a better adaptation during clinical attachment fabrication, whereas it has a negative impact on mechanical properties. CNC showed greater performance and resistance under mechanical stresses than the flowable ones, resulting in being more suitable for clinical needs.

Influence of putrefactive decay of the hoof horn in sheep on its biochemical and biomechanical properties and hemodynamics in sick animals

Sheep breeding is currently an intensively developing branch of animal husbandry. However, one of the limiting factors of its further economically viable development is the mass distribution in the conditions of large sheep-breeding farms with a non-walking technology for keeping purulent-necrotic and putrefactive lesions in the tissues of the distal part of the limbs. The etiology and pathogenesis of these pathologies is currently not fully scientifically substantiated and detailed. In this regard, we assessed the effect of putrefactive decay of the hoof horn in sheep on its biochemical and biomechanical properties, as well as on hemodynamics in diseased animals in comparison with clinically healthy ones. According to the results of the studies, it was determined that during the putrefactive decay of the hoof horn, the percentage of moisture was higher by 12.37%, and the inorganic residue (ash), fat, protein and sulfur was lower by 73.84%, 36.84%, 5.92 % and 3.82% than in its normal morpho-functional state, respectively. This, in turn, had an impact on the biomechanical properties of the hoof horn, namely, during its putrefactive decay, a decrease in compressive elasticity by 3.82%, tensile strength by 28.76%, resistance to repeated bending by 9.61% was recorded relative to similar biomechanical indicators in samples of the hoof horn obtained from clinically healthy sheep. At the same time, in the hemodynamics of diseased animals with putrefactive decay of the hoof cover, in a comparative aspect with similar hematological indicators in clinically healthy sheep, a decrease in the number of erythrocytes and platelets by 28.94% and 7.03%, a decrease in hemoglobin concentration and hematocrit value by 22.88 % and 8.80%, an increase in the number of leukocytes and erythrocyte sedimentation rate by 89.14% and 44.70%, respectively.

Binding affinity of aniline-substituted dodecaborates to cyclodextrins.

A new set of hybrid guest molecules bearing organic and inorganic residues have been studied for their recognition by cyclodextrins in aqueous solution. The guest molecules consist of nitroanilines linked through their amino group to the dodecahydrido-closo-dodecaborate cluster B12H122-, which serves as an anchor group. They show sizable affinity to cyclodextrins, and unexpected photophysical properties, with a very strong and low-energy charge-transfer band. The dodecaborate cluster increases the pKa of the anilines by 5.0 to 5.7 pH units, and the deprotonated forms of the o- and p-nitroaniline derivatives show strong charge transfer absorption bands in the visible part of the spectrum.

Synthesis and mechanical characterization of geopolymeric mortars derived from inorganic industrial waste from Peruvian informal mining

The geopolymeric mortars obtained by the chemical process of geopolymerization of waste from the Peruvian informal mining industry and subsequent addition of fine sand, were mechanically evaluated under ambient temperature and atmosphere conditions. The mechanical results found in the geopolymer mortars were compared with those found in conventional Portland cement mortars (control). The maximum uniaxial compressive stress values for the geopolymer mortars ranged from 7.5 to 27.1 MPa, with the best results when a binder:fine sand ratio of 1:2, molarity of the hardener solution of 20 M and a hardener solution:binder ratio of 0.6 was considered. The microstructure found for both types of mortars studied (control and geopolymeric) consisted of a continuous interconnected phase of binder (cement or geopolymerized inorganic mining residue) and a dispersed phase of small fine sand particles, located within the binder phase. The average real density and porosity of the geopolymeric materials studied were 2.71 g/cm3 and 27%, respectively.

Performance of non-thermal plasma reactor for removal of organic and inorganic chemical residues in aqueous media

In this work, the performance of an atmospheric air-assisted plasma reactor was evaluated for the oxidative degradation of azo (orange G and congo red) and non-azo (crystal violet, and coomassie brilliant blue) textile dyes and removal of hardness in an aqueous medium. Dye degradation efficiency was evaluated at different applied voltages (2–6 kV), pH (2.85–11.44), and initial dye concentrations (5–25 ppm). Nearly 99% degradation efficiency (at 5 ppm concentration) could be achieved in 30 min treatment time for all dyes. Degradation efficiency showed a direct relationship with applied voltage and an inverse relationship with the initial dye concentration. Moreover, higher degradation efficiencies were observed at neutral pH than in the acidic and alkaline ranges. The pseudo-first-order kinetic model exhibited a better correlation coefficient (R2 > 0.90) in explaining the degradation kinetics of dyes. The water hardness was dropped by 55.5% after 60 min of plasma treatment. Also, the crystalline structure and morphology of water samples containing salts before and after the treatments were analyzed using XRD and SEM. The average crystalline size of untreated and plasma-treated samples is calculated to be 197.9 nm and 98.1 nm respectively. The concentration of O3, OH., H2O2, NO2− and ROS species increased linearly with increasing treatment time. The energy yield and energy consumption for degradation and water hardness removal were ∼0.016 g kW/h and ∼0.3932 g kW/h, 1.08*107 J/L, and 2.16*106 J/L respectively. Moreover, atmospheric pressure gliding arc discharge-based air plasma discharge was computationally modeled and electrical characteristics such as electron density, electric potential, electron temperature, absolute electron flux and charged species (positive and negative) density were examined at different applied voltages. Overall, the atmospheric air-assistant cold plasma process shows promising potential for the removal of chemical residues in water.

Bentonite as an active natural filler for silicone leading to piezoelectric-like response material

Raw sodium bentonite (Bent) without preliminary treatments is incorporated as a filler in a silicone matrix, from 5 to 100 parts per hundred (pph), by weight, by simple mixing in solution. The mixtures are processed as films and stabilized by condensation crosslinking at room temperature. Besides being environmentally safe and non-toxic, bentonite is 30 times cheaper than polydimethylsiloxane (PDMS), so the cost price of composites can be reduced by over 40%. Studies on the effects of bentonite addition as filler on the properties of composites reveal that thermal stability is not significantly affected, while an increase in the amount of inorganic residue with an increase of Bent content is recorded. More importantly, the mechanical and dielectric properties are significantly influenced by the Bent content in the PDMS matrix. The Young's modulus increases, while the elongation decreases, indicating a stiffening of the material and a decrease in its elasticity as the Bent load increases. Most notably, the dielectric permittivity increases up to more than five times at 103 Hz by adding 100 pph Bent, while the dielectric losses remain acceptable, especially at high frequencies for all composites. Furthermore, the study of composite films through Piezoresponse Force Microscopy and piezoelectric testing system reveals an outstanding piezoelectric-like response for composites with a high Bent content. The wide-angle X-ray diffraction indicates an increase of the crystalline fraction - the main factor that influences the apparent piezoelectric coefficient - with increasing the Bent load.

Evaluation of organic and inorganic gunshot residues in various populations using LC-MS/MS

This work investigated the prevalence of organic and inorganic gunshot residue within two main subpopulations, 1) non-shooters, including groups with low- and high-risk of potentially containing GSR-like residues, and 2) individuals involved in a firing event (shooters, bystanders, and shooters performing post-shooting activities). The study analyzed over 400 samples via a liquid chromatography-mass spectrometry (LC-MS/MS) methodology with complexing agents. Exploratory statistical tools and machine learning algorithms (neural networks, NN) were used to evaluate the resulting mass spectral and quantitative data. This study observed lower occurrences of OGSR compounds in the non-shooter populations compared to IGSR analytes. The presence of GSR on authentic shooters versus other potential sources of false positives, such as bystanders and professions including police officers, agricultural workers, and mechanics, were further assessed by utilizing machine learning algorithms trained with the observed OGSR/IGSR traces. The probability of false negatives was also estimated with groups who performed regular activities after firing. Additionally, the low-risk background set allowed documentation of GSR occurrence in the general population. The probabilistic outputs of the neural network models were utilized to calculate likelihood ratios (LR) to measure the weight of the evidence. Using both the IGSR and OGSR profiles, the NN model’s accuracy ranged from 90 to 99%, depending on the subpopulation complexity. The log-LR histograms and Tippet plots show the method can discriminate between each sub-population and low rates of misleading evidence, suggesting that the proposed approach can be effectively used for a probabilistic interpretation of GSR evidence.

Thermogravimetric and Biological Studies of Organotin(IV) Complexes with 4-(Hydroxymethyl)piperidine-1-Carbodithioic Acid

Present studies were conducted to perform thermogravimetric characterization and biological activity investigations of organotin dithiocarbamates of general formulae R3SnL (R = n-Bu, 1; Ph, 2; Cy, 3), R2Sn(Cl)L (R = Me, 4; Ph, 5) and R2SnL2 (R = Me, 6) where L = 4-(hydroxymethyl)piperidine-1-carbodithioate. A novel procedure was also developed for the synthesis of product 2 by direct reflux of 4-(hydroxymethyl)piperidine-1-carbodithioic acid (HL) with triphenyltin(IV) hydroxide. HL was decomposed at low temperatures as compared to the metal complexes. The coordinated products were degraded leaving behind the tin or SnOCl inorganic residues. The products1-6 have shown excellent antimicrobial activities against the tested bacterial (Escherichia coli, Salmonella typhi, Staphylococcus aureus, and Bacillus subtilis) and fungal (Fusarium solani, Aspergillus niger, Alternaria solani, and Fusarium verticillioides) strains. The biological activities were found to depend upon the substitution pattern at the central tin atom.

Bullet contribution to inorganic residue on targets

Identifying the composition and the physical characteristics of the bullet that generated a specific hole in the victim's clothes or skin may be crucial in shooting incident reconstructions. In forensics, chemographic tests are routinely conducted to visualize lead, copper, or nitrite deposits around entrance holes with the aim of confirming a projectile impact or estimating the shooting distance. A quantitative chemical analysis of the particles collected from the periphery of an entrance hole is required for identifying the type of passing bullet. In real cases, such analysis would be affected by the possible cross-contributions of both inorganic residue from the discharged ammunition primer and metallic fragments from previous rounds projected from the gun barrel. The actual contribution of the sole bullet to the composition of the inorganic residue deposited on target is then hardly distinguishable. In the present study, the deposits left by three different copper/zinc jacketed bullets on targets were analysed by inductively coupled plasma optical emission spectrometry and by X-ray fluorescence spectrometry. To reduce any possible source of contamination, a heavy metal free primer mixture and a brand new pistol were used. Elements of interest were quantified varying the shooting distances with the aim of identifying different bullet contributions to the inorganic residue on targets.

Selective dry etching of UV-nanoimprinted resin passivation masks for area selective atomic layer deposition of aluminum oxide

To demonstrate area selective atomic layer deposition (ALD) using UV-nanoimprinted resin patterns as physical passivation masks, we investigated the removal of UV-cured resin films subjected to sequential mutual doses of trimethylaluminum (TMA) and H2O by using dry etching procedures. On the basis of the removal of a residual layer characteristic from imprint resin patterns by anisotropic oxygen reactive ion etching (O2 RIE), oxidatively etched UV-cured films were modified with TMA and H2O in an ALD-like cyclic manner. Atomic force microscopy and time-of-flight secondary ion mass spectrometry [time-of-flight secondary ion mass spectrometry (TOF-SIMS)] analysis suggested that the combination of physical Ar ion milling and subsequent chemical O2 RIE enabled the elimination of oxidized UV-cured resin masks modified with 5-cycle TMA doses. By contrast, Ar ion milling or O2 RIE left organic or inorganic residues on silicon surfaces, respectively. A TMA-modified hybridized resin layer was etched by physical Ar ion milling; subsequently, the organic residual resin layer was removed by chemical O2 RIE in the case of 5-cycle modification with TMA. The mapping image of Al+ visualized by TOF-SIMS suggested that line patterns of aluminum oxide were left selectively on unmasked silicon substrate surfaces by site-selective dry etching of TMA-modified imprint resin passivation masks with 500 nm linewidth.

Formic acid pulping process of rice straw for manufacturing of cellulosic fibers with silica

Emerging technology has the potential to develop entirely new approaches for producing cellulose fiber-based materials along with fuels and chemical raw materials like lignin and furfural. Rice straw is a rich source of cellulosic fibers and inorganic micronic-sized particles termed as ash. They can prove helpful in development of new or enhanced agricultural residue-based materials and products that offer cost effective substitutes for nonrenewable materials used in different domestic and industrial applications. Lignocellulose is an abundant material that is submicronic at the basic level. Rice straw is a fibrous lignocellulosic material obtained as agricultural residue, but it differs from most crop residues in its high content of silicon dioxide (SiO2). Ash content on a dry weight basis ranges from 13% to 20%, varying according to the state of conservation of the straw after harvest. The ash in rice straw has nearly 75% SiO2. The particle size analysis shows variation from few microns to hundreds of microns for inorganic residues left after burning at high temperatures above 550°C. Proximate analysis of rice straw shows that it contains 54% to 56% holocellulose and 15% to 18% lignin, both of which are natural biopolymers. The compound analysis shows the different compounds present in rice straw ash. Rice straw is available in hundreds of million tons in India and other Asian countries, so suitable technologies are required to convert rice straw from a biomass waste to useful bioproducts like pulp, paper, and paperboard. This research paper is intended to obtain pulp with fibers having inherent silica present in it to give high opacity paper and better bonding between fibers.

On the questioned presence of fluorine in inorganic gunshot residue. Case work experience and experimental evidences

According to the active ASTM E1588–20 Standard Practice for Gunshot Residue (GSR) Analysis, particles from lead-based primers classified as “characteristic of GSR” will have the chemical composition lead/antimony/barium. Further elements allowed to be incorporated into GSR are explicitly listed in the ASTM guideline. Fluorine is not considered a possible additional element as no common sources of F in shooting related activities have ever been documented. Moreover, presence of fluorine was demonstrated in GSR-similar particles produced by airbag deployments and the possibility to use F as a chemical marker to exclude any discharging of a firearm was consequently suggested. In authors’ case work experience, fluorine containing particles were found on stubs collected from victims’ clothes, discharged firearms and shooters’ hands. Adopting a “case by case” approach, a firearm-related fluorine origin was then sought. Fluorine-based protective lubricants, used both for guns and ammunition components, were experimentally confirmed as a possible source of F in GSR.

A study of the effect of working parameters and validation of SEM/EDS method for determination of elemental composition of commonly encountered GSR samples in shooting events in Kosovo.

Reliability of forensic evidences for presence of inorganic gunshot residue (iGSR) on a given surface strongly depends on the performance of scanning electron microscopy/energy dispersive X-ray spectrometry (SEM-EDS) method. This article presents the results from a study of the effect of SEM/EDS working parameters on the method performance and quality of iGSR data, as well as a development of a database of iGSR encountered in R Kosovo. The optimal working parameters of SEM/EDS were established by one-variable-at-a-time approach and the method was validated according to ASTM1588-10. The precision, trueness, and expanded uncertainty for PbBaSb particles were estimated and the method was assessed as a "fit for purpose" with a satisfactory performance (z-score<2). Expended uncertainty of quantification of GSR particles estimated by single laboratory and quality control approach was 6% (k=2). The validated SEM/EDS method was applied for identification of characteristic iGSR particles in samples from shooting events in Kosovo. The method was demonstrated to be capable of providing a legal proof for iGSR existence on a specific surface. The quality of the results was not influenced by the origin of iGSR. Five hundred fifty-five samples from 144 cases occurred during the last 3years were analyzed and 14% rate of positive results was found.

Bio-based and compostable polyesters in food contact: analysis of monomers and (in)organic fillers

ABSTRACT Polyesters labelled as bio-based or compostable are increasingly common among the ‘bioplastics’ in use as food contact materials (FCM). The knowledge of material composition is mandatory to predict potential leachable oligomers as well as to partly evaluate the correctness of the label ‘bioplastic’, which is used for promotional purposes. The composition of (bio)polyesters can be determined by alkaline hydrolysis of the entire material and subsequent analysis of the monomers via high-performance liquid chromatography with diode array detection and GC-MS detection. Thirty-three frequently used monomers (polycarboxylic acids, hydroxy carboxylic acids, polyols) including highly polar monomers such as lactic acid were analysed with detection limits below 10 g/kg of the material. Lactic acid enantiomer elucidation was performed using an enzyme assay. The content of non-hydrolysable residue was determined gravimetrically after hydrolysis, and the inorganic residue after washing. The composition of 12 polyesters mostly in food contact, labelled as bio-based or compostable and sampled from the market was elucidated recovering 92–101% of the total mass by summing up the determined monomers and non-polyester contents. Seven different monomers were detected in the 12 samples (up to four different monomers per sample), lactic acid being the most common (9 samples) with contents ranging from a minor component (about 11 mol%) up to the only monomer found in the material. The ratio of d- to l-lactic acid ranged from 0.3:99.7 to 4.7:95.3 (w/w). The non-hydrolysable (in)organic residue was quantified in amounts of up to 390 g/kg. Overall, the presented analytical protocol is a fundamental tool helping both to verify the appropriateness of labelling as biopolyesters as well as to predict potential leachables such as oligomers during an FCM risk assessment.

The implications of facility design and enabling policies on the economics of dry anaerobic digestion.

Diverting organic waste from landfills provides significant emissions benefits in addition to preserving landfill capacity and creating value-added energy and compost products. Dry anaerobic digestion (AD) is particularly attractive for managing the organic fraction of municipal solid waste because of its high-solids composition and minimal water requirements. This study utilizes empirical data from operational facilities in California in order to explore the key drivers of dry AD facility profitability, impacts of market forces, and the efficacy of policy incentives. The study finds that dry AD facilities can achieve meaningful economies of scale with organic waste intake amounts larger than 75,000 tonnes per year. Materials handling costs, including the disposal of inorganic residuals from contaminated waste streams and post-digester mass (digestate) management, are both the largest and the most uncertain facility costs. Facilities that utilize the biogas for vehicle fueling and earn associated fuel credits collect revenues that are 4-6x greater than those of facilities generating and selling electricity and 10-12x greater than facilities selling natural gas at market prices. The results suggest important facility design elements and enabling policies to support an increased scale of organic waste handling infrastructure.

Molybdenum in Gunshot Residue: Experimental Evidences and Detection Challenges in the Presence of Lead and Sulfur.

Inorganic gunshot residue (GSR) analysis is carried out by scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) in many forensic laboratories. Characteristic GSR often consists of lead–barium–antimony, commonly associated with sulfur. The strength of forensic GSR evidence increases when unusual elements are found in residues collected both from the suspect and from the discharged firearm. The presence of molybdenum in GSR, due to the use of MoS2 lubricants in firearms, is experimentally demonstrated here for the first time. The most intense molybdenum X-ray emissions are MoL peaks at 2.3 keV which overlap with PbM and SK families due to the poor resolution of EDS detectors. When Pb, S, and Mo are allegedly present in the same particle, the reliability of automatic EDS routines is at risk. Missing identifications or false detections and exclusions may then occur. Molybdenum should be considered as detected only if MoK emissions meet the peak-to-background ratio minimum requirements. A strategy to spot Mo-containing residues is described, based on the automated search of MoS2, using a new “Sulfur only” class added to the classification scheme, followed by careful manual review of all GSR particles at an acceleration voltage of 30 kV. Our proposal improves commonly adopted forensic procedures currently followed in casework.

Utilization of inorganic solid wastes in cementitious materials – A systematic literature review

Civil construction is an opportune way of using industrial by-products, leading to the reduction of consumption of natural resources. This paper is a systematic review of the literature, addressing the application of inorganic residues in cementitious composites. The Web of Science search was performed using keywords: Foundry Sand; Foundry Slag; Electric Arc Furnace Dust; Concrete Waste; Ceramic Waste; Glass Waste; Sugarcane Bagasse Ash; Bamboo Leaf Ash. A total of 107 papers were analyzed, and the effects of these residues in the mechanical properties, the optimal percentages for substitution, main applications and suggestions for future research are organized in this paper.