High Density Research Articles

Preliminary fabrication and analysis of a novel porous Cu-CNT composite for photothermal applications

Employing Chemical Vapor Deposition (CVD), we created and then investigated properties of a novel carbon-nanotube porous-copper composite (porous Cu-CNT composite). Field-Emission Scanning Electron Microscopy (FESEM) and Energy-Dispersive x-ray Spectroscopy (EDX) clearly revealed successful coating of CNTs, with its density increasing proportionally with the deposition time. In addition, Raman spectroscopy confirmed the constitution of the composite, which included oxygen, copper, and a high level of carbon. We also found out that the higher density of CNTs led to a significant improvement in light absorption in the visible spectrum, compared with the uncoated porous copper. This special property, combined with the porosity of the copper sample, as well as the exceptional thermal and optical properties of CNTs, makes the composite a highly promising candidate for photothermal applications.

Early-stage silver growth during sputter deposition on SiO2 and polystyrene – Comparison of biased DC magnetron sputtering, high-power impulse magnetron sputtering (HiPIMS) and bipolar HiPIMS

The integration of silver thin films into optoelectronic devices has gained much interest due to their exceptional properties in terms of conductivity and compatibility with flexible substrates. For this type of application, ultra-thin layers are desirable, because of their optical transparency. Standard direct current magnetron sputtering (DCMS) is known to lead to undesirable formation of islands at low effective film thicknesses on typical substrates like SiO2 or polystyrene (PS). Therefore, in this study, we explore high-power impulse magnetron sputtering (HiPIMS) with optional further acceleration of metal ions by biasing the substrate or an additional positive pulse (bipolar HiPIMS) for the fabrication of ultra-thin silver layers. The morphology and electrical properties of ultra-thin silver layers with selected effective thicknesses are characterized on SiO2 and PS substrates. The growth evolution of characteristic parameters is further investigated by in-situ grazing-incidence small-angle X-ray scattering (GISAXS). The results show that HiPIMS deposition yields films with a higher density of clusters than DCMS leading to a percolation threshold at lower effective film thicknesses. This effect is amplified by further ion acceleration. Thus, we suggest HiPIMS as a promising technique for fabricating ultra-thin, conductive layers on organic and oxide substrates.

The effect of forest structural complexity on tick-borne pathogens in questing ticks and small mammals

Forest management is increasingly focused on enhancing structural complexity. An increase in structural complexity is assumed to increase the abundance and diversity of fauna, including vertebrates. This faunal assemblage serves, in turn, as host community for a suite of vectors and their pathogens, so that structural complexity may cascade through a network of interactions in forest ecosystems. Here we use a network of 19 forest plots representing a gradient of structural complexity and dominant tree species (oak, beech, poplar) to test two hypotheses on the effect of structural complexity on the prevalence of tick-borne pathogens. Our first hypothesis is that tick densities will increase with increasing structural complexity, assuming that each life stage has higher chances of finding a suitable host. The second hypothesis is that the pathogen prevalence in ticks and small mammals decreases (cf. dilution hypothesis) or increases (cf. amplification hypothesis) with increasing structural complexity. These expectations are tested through a community-level analysis, looking at twelve pathogens: seven genospecies of Borrelia (B. afzelii, B. bavariensis, B. garinii, B. burgdorferi sensu stricto, B. spielmanii, B. valaisiana and B. miyamotoi), Babesia s.s., Babesia microti, Anaplasma phagocytophilum, Rickettsia helvetica and Spiroplasma ixodetes. We found that more structurally complex forests have a higher density of questing nymphs (in June and July, during the peak of nymph activity). We did not find a clear change in pathogen prevalence with increasing structural complexity in ticks, wood mice and bank vole; the effect was different for the different pathogens and between the different dominant tree species. No clear co-occurrence patterns of pathogens were found. The density of infected nymphs and thus the disease risk is higher in more complex forests. A potential solution is to focus on decreasing the human-tick interactions in forests instead of trying to decrease the number of questing ticks.

What drives wild boar density and population growth in Mediterranean environments?

Accurate prediction of fluctuations of wildlife local number of individuals is crucial for effective population management to minimise human-wildlife conflicts. Climate, habitat, food availability, and density dependence are among the main factors influencing mammalian population dynamics. In southern Europe, precipitation and temperature, particularly during summer have been suggested as key factors affecting wild boar (Sus scrofa L.). However, there is uncertainty regarding the role of these factors and the mechanisms driving population fluctuations. This study utilized long-term data of wild boar populations from 14 study sites collected for 23 years in Catalonia, Spain, to analyse the factors that drive population density and growth rate. Generalized Additive Mixed Models (GAMM) explained respectively, 94 % and 65 % of the density and growth rate variability. Spring precipitation in both current and previous year, female weight, and forest cover (particularly above 60 %) were directly associated with higher wild boar densities and population growth rates. The interaction between crop cover and total annual precipitation also played a significant role in determining population density. Higher densities were linked to lower population growth in the following year, likely due to a density-dependent process. These results suggest that the expected decrease in rainfall linked with global warming may limit the availability of natural resources and potentially slow wild boar population growth. Nevertheless, wild boar can exploit alternative anthropogenic food sources, potentially leading to an increase of human-wildlife conflicts. Therefore, incorporating management policies aimed at restricting wild boar access to human food sources is key for controlling their reproductive output. Additionally, landscape management strategies targeted at diminishing refuge and resource availability in regions experiencing high wild boar impact are essential for contributing to sustainable coexistence between wild boars and human populations.

STUDY OF PHYSICAL PROPERTIES MECHANICAL PROPERTIES AND THE DEVELOPMENT OF PARTICLEBOARD FROMDURIAN PEEL USING A COMPRESSION MOLDING PROCESS

This research is the process study of producing particleboard from durian peel using the compression molding process. These studies are the physical and mechanical properties of particleboard from durian peel. The results found that the flexural test and the tensile test of furniture material sheets from durian peels at a ratio of durian pulp to glue water were 1:0.2, 1:0.4, 1:0.6, 1:0.8, 1:1, and 1:1.5, respectively. A specimen with dimensions of width 50 x length 200 x thickness 10 millimeters was tested with a machine. The universal testing machine of six samples in each ratio. It shows that the mechanical strength values increased when the ratio of water mixed with glue increased. The durian pulp has a better adhesion. This results are in a higher density as the ratio increases and at the ratio of 1:1.5, it has the highest strength and an average flexural strength of 5.74 MPa but it has not yet passed the criteria set by TISI 876-2004 with a flexural strength of not less than 14 MPa for plywood sheets with a thickness exceeding 6.0-13.0 millimeters. It has an average tensile strength value perpendicular to the surface of 0.49 MPa, which passes the criteria set by TISI standard, with the tensile strength value perpendicular to the surface not less MPa. than 0.40 for plywood with a thickness of more than 6.0-13.0 millimeters. For the testing of the burning rate of particleboard made from durian peels, it was found that the burning rate decreased when the ratio of water mixed with glue increased due to the increasing density of the workpiece at a ratio of 1:1.5 and it can stop the combustion by itself.

Examining Teachers' Professional Relationships, Friendship, and Trust Networks via Social Network Analysis

In this study, Social Network Analysis method was used to determine the professional relationships, friendships and trust networks that teachers established with their colleagues. The study group of the research consists of 35 teachers working in a public secondary education institution in Aydın province. A three-question structured interview form developed by the researchers was used to determine teachers' social networks. Data analysis was carried out through the UCINET 6.0 program. When the findings regarding the positions of teachers in the professional relationship network, friendship network and trust network were examined, it was determined that the network structure with the highest number of connections was the friendship network (ties = 97), followed by the professional relationship (ties = 95) and the trust network (ties = 66). In all social networks, teachers with mathematics, guidance, literature and biology branches were found to be at the center of the network, acting as a bridge between other actors and providing information and resource flow. According to the findings, it was determined that the network with the highest density (dens. = 0.082), bilateral (dia. = 0.198) and triad (triad = 0.330) reciprocity rate was the friendship network. This study, which examines the professional relationships, friendships and trust networks that teachers establish with their colleagues, is thought to be important in revealing the relationships between teachers and analyzing the current situation.

STUDI KEANEKARAGAMAN MIKROALGA DI SUNGAI MARGASATWA RAGUNAN SEKITAR KANDANG BUAYA

Microalgae are microscopic unicellular organisms that have varying sizes, shapes, and types, have photosynthetic pigments, are photoautotrophic, and are found in aquatic environments. Microalgae have certain limits of tolerance to water chemical physics factors. The presence of microalgae in water can be used as an indicator of the state of the water. This study aims to identify the diversity of microalgae as an indicator of the water quality present in the river around the Ragunan Margasatwa crocodile cage. Sampling was done in the Ragunan Margasatwa Park river near the crocodile cage. Samples of macroalgae are visually identified and include morphology, color, shape, and other characteristics. Based on the observations, it can be concluded that the river ecosystems around the crocodile cages are under low ecosystem pressure. The diversity index generally has a range of values between 1.5 and 4, and lower values reflect increasing ecosystem instability. The lowest microalgae density was found at station 1, which is 120 ind/ml. Individuals with the highest density at station 2, the species Aphanothece sp. with a density value of 293.3 ind/mL.

The Short-Term Effect of Sleeve Gastrectomy on Blood Lipid Parameters and Emotional Appetite in Morbidly Obese Individuals

Background: Obesity is a public health problem that has an increasing effect all over the world and affects health in many ways. In cases where the BMI exceeds 40 kg/m2 or in individuals with a BMI of 35 kg/m2 and accompanying diseases, weight loss cannot be achieved, thus bariatric surgeries are applied. Methods: In this study, the relationship between blood lipid parameters and emotional appetite status in the pre-operative and early post-operative periods of individuals who underwent sleeve gastrectomy (n = 47) was investigated. Results: As a result of the study, total cholesterol, triglyceride, high density lipoprotein (HDL) cholesterol, and low density lipoprotein (LDL) cholesterol values of individuals in the early post-operative period were statistically significantly decreased (p< 0.001). It was found that there was a weak positive correlation between individuals' early post-operative total cholesterol and LDL cholesterol values, positive mood and state total scores, and negative emotion and state total scores (p

Correlation of Electrical Conductivity and Microstructure with the Band Gap of Oxysulfide Glass-Ceramics for Na-Ion Battery

In the present investigation, a glass-ceramics with the composition of xNa2S + (100–x)P2S5, where x = 40, 45, 50 and 55, were successfully synthesized by employing the melt-quenching method. Comprehensive characterization of the glass-ceramic samples was conducted using X-ray diffraction (XRD), UV-visible spectroscopy, impedance spectroscopy (IS) and field emission scanning electron microscopy (FE-SEM) techniques. The XRD analysis revealed the presence of three distinct phases, namely NaPO3, Na2S2O3 and Na3PS4, in all samples. Significantly, NaPO3 and Na2S2O3 exhibited an orthorhombic crystal structure, while Na3PS4 displayed a tetragonal crystal structure. The densities of the synthesized samples fell within the range of 2.24 to 2.35 g/cc, surpassing those of Li2S-based solid electrolytes commonly used in portable devices. The band gap of the materials varied from 2.99 to 3.60 eV. Significantly, an inverse relationship between Na2S content (modifier) and band gap was observed, indicating a decrease in band gaps with increasing Na2S content. This phenomenon is beneficial for enhancing ionic conductivity. At ambient temperature, samples with x values of 50 and 55 demonstrated remarkable conductivity on the order of 10-4 S cm-1. Overall, the synthesized glass ceramics exhibit promising features, such as higher density compared to conventional Li2S-based solid electrolytes and favourable band gap values, suggesting their potential application in enhancing ionic conductivity for various electronic devices.

Leaching characteristics of metals from recycled concrete aggregates (RCA) and reclaimed asphalt pavements (RAP)

Recycled concrete aggregates (RCA) and reclaimed asphalt pavements (RAP) are two construction waste products that are commonly used in the road construction industry. Besides many advantages, pollutants leaching from RCA and RAP are highlighted as the most concerning environmental issue. This study investigated metals leaching characteristics from RCA and RAP due to the variations in key influential factors of pH, dissolved organic carbon (DOC), compaction and liquid to solid ratio (L/S). The leaching tests for RCA and RAP were carried out separately and additionally, the standard leaching test was conducted as the benchmark for leaching investigations. Study outcomes revealed that the combined influences of factors are variable for RCA and RAP, while influences are also variable for individual metals. L/S ratios considerably affect the release of metals from RCA under saturated conditions, facilitating high metal concentrations in the leachate. On the other hand, acidic solutions are more favourable for leaching of metals from RAP. The influence of DOC in solution was minimal on the metal leachability. Interestingly, the increased degree of compaction with a higher density of materials presented the highest negative influence on metal leachability, suggesting that the metal leachability can significantly reduce, in particular when the RCA and RAP are used for the sub-base layers of road structure with a higher degree of compaction. However, the use of these recycled materials under field conditions should be further studied as there is an increasing concern of metal leaching from RCA and RAP with respect to recreational and drinking water thresholds.

Investigating the performance improvement of lithium-ion battery cooling process using copper fins and phase change materials (PCMs)

This study investigates utilizing phase change materials (PCMs) along with metallic fins for passive cooling of lithium-ion batteries. PCMs have low thermal conductivity, which is enhanced by incorporating copper or aluminum fins. Numerical simulations using ANSYS FLUENT's Solidification & Melting solver in an axisymmetric configuration are performed. PCM cooling outperforms air cooling, providing up to 15 °C lower maximum battery temperatures as long as PCM remains solid. The findings from the analysis of air cooling versus cooling with PCM demonstrate that the use of phase-change materials enhances battery cooling performance for a specific duration, provided that these materials do not fully liquefy. Adding fins further improves cooling for 0.2 mm thickness, 6 copper fins of 11.67 mm height give optimal performance with 8 °C lower peak temperatures than without fins. Copper fins outperform aluminum due to 60 % higher thermal conductivity but have 3X higher density. For longitudinal fins, 4 fins of 10 mm height perform better than 10 fins of 3 mm height. With high conductivity PCMs like paraffin wax (0.242 W/m.K), varying fin count has minimal impact as heat distributes rapidly. This study establishes guidelines for optimizing PCM-fin geometries and materials to maximize passive lithium-ion battery cooling performance.

Thin-Film Composite Membrane Compaction: Exploring the Interplay among Support Compressive Modulus, Structural Characteristics, and Overall Transport Efficiency.

Water scarcity has driven the demand for water production from unconventional sources and the reuse of industrial wastewater. Pressure-driven membranes, notably thin-film composite (TFC) membranes, stand as energy-efficient alternatives to the water scarcity challenge and various wastewater treatments. While pressure drives solvent movement, it concurrently triggers membrane compaction and flux deterioration. This necessitates a profound comprehension of the intricate interplay among compressive modulus, structural properties, and transport efficacy amid the compaction process. In this study, we present an all-encompassing compaction model for TFC membranes, applying authentic structural and mechanical variables, achieved by coupling viscoelasticity with Monte Carlo flux calculations based on the resistance-in-series model. Through validation against experimental data for multiple commercial membranes, we evaluated the influence of diverse physical parameters. We find that support polymers with a higher compressive modulus (lower compliance), supports with higher densities of "finger-like" pores, and "sponge-like" pores with optimum void fractions will be preferred to mitigate compaction. More importantly, we uncover a trade-off correlation between steady-state permeability and the modulus for identical support polymers displaying varying porosities. This model holds the potential as a valuable guide in shaping the design and optimization for further TFC applications and extending its utility to biological scaffolds and hydrogels with thin-film coatings in tissue engineering.

Low-Temperature Migration-Enhanced Epitaxial Growth of High-Quality (InAs)4(GaAs)3/Be-Doped InAlAs Quantum Wells for THz Applications

This investigation explores the structural and electronic properties of low-temperature-grown (InAs)4(GaAs)3/Be-doped InAlAs and InGaAs/Be-doped InAlAs multiple quantum wells (MQWs), utilizing migration-enhanced epitaxy (MEE) and conventional molecular beam epitaxy (MBE) growth mode. Through comprehensive characterization methods including transmission electron microscopy (TEM), Raman spectroscopy, atomic force microscopy (AFM), pump–probe transient reflectivity, and Hall effect measurements, the study reveals significant distinctions between the two types of MQWs. The (InAs)4(GaAs)3/Be-doped InAlAs MQWs grown via the MEE mode exhibit enhanced periodicity and interface quality over the InGaAs/Be-InAlAs MQWs grown through the conventional molecule beam epitaxy (MBE) mode, as evidenced by TEM. The AFM results indicate lower surface roughness for the (InAs)4(GaAs)3/Be-doped InAlAs MQWs by using the MEE mode. Raman spectroscopy reveals weaker disorder-activated modes in the (InAs)4(GaAs)3/Be-doped InAlAs MQWs by using the MEE mode. This originates from utilizing the (InAs)4(GaAs)3 short period superlattices rather than InGaAs, which suppresses the arbitrary distribution of Ga and In atoms during the InGaAs growth. Furthermore, pump–probe transient reflectivity measurements show shorter carrier lifetimes in the (InAs)4(GaAs)3/Be-doped InAlAs MQWs, attributed to a higher density of antisite defects. It is noteworthy that room temperature Hall measurements imply that the mobility of (InAs)4(GaAs)3/Be-doped InAlAs MQWs grown at a low temperature of 250 °C via the MEE mode is superior to that of InGaAs/Be-doped InAlAs MQWs grown in the conventional MBE growth mode, reaching 2230 cm2/V.s. The reason for the higher mobility of (InAs)4(GaAs)3/Be-doped InAlAs MQWs is that this short-period superlattice structure can effectively suppress alloy scattering caused by the arbitrary distribution of In and Ga atoms during the growth process of the InGaAs ternary alloy. These results exhibit the promise of the MEE growth approach for growing high-performance MQWs for advanced optoelectronic applications, notably for high-speed optoelectronic devices like THz photoconductive antennas.

Study on Water Splitting of the 214-Type Perovskite Oxides LnSrCoO4 (Ln = La, Pr, Sm, Eu, and Ga).

We present a study on the electrocatalysis of 214-type perovskite oxides LnSrCoO4 (Ln = La, Pr, Sm, Eu, and Ga) with semiconducting-like behavior synthesized using the sol-gel method. Among these five catalysts, PrSrCoO4 exhibits the optimal electrochemical performance in both the oxygen evolution reaction and the hydrogen evolution reaction, mainly due to its larger electrical conductivity, mass activity, and turnover frequency. Importantly, the weak dependency of LSV curves in a KOH solution with different pH values, revealing the adsorbate evolving mechanism in PrSrCoO4, and the density functional theory (DFT) calculations indicate that PrSrCoO4 has a smaller Gibbs free energy and a higher density of states near the Fermi level, which accelerates the electrochemical water splitting. The mutual substitution of different rare-earth elements will change the unit-cell parameters, regulate the electronic states of catalytic active site Co ions, and further affect their catalytic performance. Furthermore, the magnetic results indicate strong spin-orbit coupling in the electroactive sites of Co ions in SmSrCoO4 and EuSrCoO4, whereas the magnetic moments of Co ions in the other three catalysts mainly arise from the spin itself. Our experimental results expand the electrochemical applications of 214-type perovskite oxides and provide a good platform for a deeper understanding of their catalytic mechanisms.

Preliminary Envelope for Large Transport Aircrafts Operating with Non-Primary Fuels AVGAS, MOGAS and F76-Dieso

This study explores the operational implications and safety considerations of using non-primary fuels—AVGAS, MOGAS, and F76 Dieso—in military transport aircraft, against the backdrop of standard aviation fuels. Through an analysis of fuel properties such as vapor pressure, density, viscosity, freeze temperature, water solubility, and thermal conductivity, this work outlines the operational envelopes for the mentioned non-primary fuels, highlighting the temperature and altitude limitations inherent to their use. The evaluation underscores the necessity of relevant testing, certification, and adherence to operational guidelines and constrains to ensure aircraft safety and reliability when standard fuels are unavailable, and hence, non-primary fuels may be required in special missions under emergency. Key findings include the specific altitude and temperature limitations for AVGAS and MOGAS to prevent fuel freezing and boiling, as well as the operational challenges posed by F76 Dieso due to its higher density and viscosity. The study also addresses the importance of managing water content in the fuel system, the flammability range of the non-primary fuels, and the considerations for fuel mixing to maintain aircraft performance and safety standards. This analysis aims to enhance the understanding of non-primary fuel usage in military transport aircraft, providing insights for system design, performance assessment, and the development of operational procedures to support military aviation in diverse operational scenarios.

Linear interaction between replication and transcription shapes DNA break dynamics at recurrent DNA break Clusters

Recurrent DNA break clusters (RDCs) are replication-transcription collision hotspots; many are unique to neural progenitor cells. Through high-resolution replication sequencing and a capture-ligation assay in mouse neural progenitor cells experiencing replication stress, we unravel the replication features dictating RDC location and orientation. Most RDCs occur at the replication forks traversing timing transition regions (TTRs), where sparse replication origins connect unidirectional forks. Leftward-moving forks generate telomere-connected DNA double-strand breaks (DSBs), while rightward-moving forks lead to centromere-connected DSBs. Strand-specific mapping for DNA-bound RNA reveals co-transcriptional dual-strand DNA:RNA hybrids present at a higher density in RDC than in other actively transcribed long genes. In addition, mapping RNA polymerase activity uncovers that head-to-head interactions between replication and transcription machinery result in 60% DSB contribution to the head-on compared to 40% for co-directional. Taken together we reveal TTR as a fragile class and show how the linear interaction between transcription and replication impacts genome stability.

Study on the Molding Factors of Preparing High-Strength Laminated Bamboo Composites.

To promote the development of the 'Bamboo as a Substitute for Steel' proposal, rotary cut bamboo veneers were applied to prepare a kind of high-strength laminated bamboo composite, which was achieved through the hot press molding method in this study. Orthogonal experiments of L9 (33) were performed, with hot-pressing temperature, pressure, and time considered as three influencing factors. Physical properties like density and moisture content, and mechanical properties like modulus of rupture (MOR), modulus of elasticity (MOE), shear strength, and compressive strength were tested for the samples. It can be obtained from the results of range analysis and ANOVA that higher density and lower moisture content were correlated with higher mechanical strength. Within the selected range of tested factors, a hot-pressing temperature and time of 150 °C and 10 min can contribute to higher density and lower moisture content, and the combination of 150 °C and 50 MPa can produce greater mechanical strength. In the thickness direction, the laminated bamboo composites displayed a notable compressed structure.

Histology and chronological magnetic resonance images of congenital spinal deformity: An experimental study in mice model

BackgroundThe natural history of the congenital spinal deformity and its clinical magnitude vary widely in human species. However, we previously reported that the spinal deformities of congenital scoliosis mice did not progress throughout our observational period according to soft X-ray and MRI data. In this study, congenital vertebral and intervertebral malformations in mice were assessed via magnetic resonance (MR) and histological images.MethodsCongenital spinal anomalies were chronologically assessed via soft X-ray and 7 T MR imaging. MR images were compared to the histological images to validate the findings around the malformations.ResultsSoft X-ray images showed the gross alignment of the spine and the contour of the malformed vertebrae, with the growth plate and cortical bone visible as higher density lines, but could not be used to distinguish the existence of intervertebral structures. In contrast, MR images could be used to distinguish each structure, including the cortical bone, growth plate, cartilaginous end plate, and nucleus pulposus, by combining the signal changes on T1-weighted imaging (T1WI) and T2-weighted imaging (T2WI). The intervertebral structure adjacent to the malformed vertebrae also exhibited various abnormalities, such as growth plate and cartilaginous end plate irregularities, nucleus pulposus defects, and bone marrow formation. In the chronological observation, the thickness and shape of the malformed structures on T1WI did not change.ConclusionsSpinal malformations in mice were chronologically observed via 7 T MRI and histology. MR images could be used to distinguish the histological structures of normal and malformed mouse spines. Malformed vertebrae were accompanied by adjacent intervertebral structures that corresponded to the fully segmented structures observed in human congenital scoliosis, but the intervertebral conditions varied. This study suggested the importance of MRI and histological examinations of human congenital scoliosis patients with patterns other than nonsegmenting patterns, which may be used to predict the prognosis of patients with spinal deformities associated with malformed vertebrae.

Investigation of the performance and emissions of a diesel engine fuelled with bio-oil generated through microwave-assisted pyrolysis of a blend of hazelnut, walnut, and polyethylene terephthalate waste

New and renewable energy sources are the most important issue nowadays. Bio-oil which can replace fossil fuel is an alternative source of energy. In this study, the performance effects and emissions of bio-oil produced by microwave-assisted pyrolysis system (MAP) from the walnut shell (WS), hazelnut shell (HS), and polyethylene terephthalate (PET) waste mixtures on a single-cylinder diesel engine were investigated. For this purpose, WS, HS, and PET wastes were mixed in two different proportions and converted into pyrolytic oil in the MAP system at 700 watts of microwave power and a 30-minute retention time. Produced pyrolytic oils were converted into bio-oil as S1 (46.25% WS + 46.25% HS + 2.5% PET) and S2 (43.75% WS + 43.75% HS + 7.5% PET) through a 3-stage basic upgrading steps. Experimental results showed that MAP of mixed WS, HS, and PET resulted in high hydrocarbon content bio-oil. In the engine experiments, bio-oil was mixed with diesel at 10%, 20%, and 30% ratios by volume and used in a diesel engine at different Brake Mean Effective Pressure (BMEP) (1.4, 2, 2.7, and 3.4 bar). Engine performance has been found to be comparable to diesel at low blend percentages. At 3.4 bar BMEP, while the brake-specific fuel consumption (BSFC) of diesel was 712 g/kWh, it was obtained as 832 and 804 g/kWh at S1 and S2, respectively. However, when the emissions were evaluated in general, it was determined that the emission values increased with increasing bio-oil/diesel blend ratios due to the high viscosity, higher density, and low cetane number of bio-oil compared to diesel.

Evaluation of a heating protocol and stocking density impact on heatstressed fattening pigs

As climate change intensifies, heat stress mitigation for pigs becomes more important. Trials involving induced heat waves are useful to test several measures (e.g. reduced stocking density) at a faster rate, but only when accurately evaluated and validated. In the present study, we investigated the suitability of an artificial heating protocol at different pig weights (experiment 1). The impact of different stocking densities on fattening pigs during an artificial heat wave (experiment 2) was also investigated. Experiment 1: Forty 20-week-old pigs weighing 96.5 ± 7.3 kg (W100) and forty 17-week-old pigs weighing 72.7 ± 9.9 kg (W70) were housed in two compartments. An artificial heat wave (heat load) was induced for 3 days. During 3-day periods before, during and after the heat load, physiological parameters (respiration rate (RR), rectal temperature (Trectal), skin temperature (Tskin) and behavior) were measured and average daily feed intake was observed. Ambient temperature, relative humidity and temperature-humidity index (THI) were monitored. Experiment 2: A total of 150 fattening pigs were randomly divided into three treatment groups: SD1.3 (1.3 m2/pig), SD1.0 (1.0 m2/pig) and SD0.8 (0.8 m2/pig). All pens had a total pen surface of 4.88 m2, corresponding with 4, 5 and 6 fattening pigs in the SD1.3, SD1.0 and SD0.8 groups, respectively. The heat load was induced for 7 days on week 21. Respiration rate and Trectal were observed as in experiment 1. Average daily gain and average daily feed intake were also noted. During the heat load, THI reached ≥ 75 (78.4 (experiment 1) and 78.6 (experiment 2)), even when relative humidity decreased to ± 45%. Every physiological parameter showed significant increases during the heat load. The prolonged heating protocol in experiment 2 also provoked significant decreases in average daily feed intake (15%) and average daily gain (19%) for all groups. Weight within the studied range of 70–100 kg did not have a significant impact on any of the parameters. However, Tskin was affected by both weight and heat load (P < 0.05), where Tskin from W100 was always lower in comparison to W70. In addition, we found that 0.8 m2/pig doubled the increase of Trectal during the heat load, namely SD0.8 (0.22 °C) compared to SD1.0 (0.12 °C) (P = 0.033) and SD1.3 (0.13 °C) (P = 0.053). This suggests that pigs housed at higher densities are less able to regulate their internal heat production. However, RR and performances were not significantly affected by heat load in this experimental set-up. A stocking density of 1.0 m2/animal may be sufficient to mitigate some negative effects of heat stress.