Relative Density Values Research Articles

Non-wood forest products potency from community forest in Gempolan Village, Karanganyar Regency, Central Java

Non-wood forest products (NWFPs) are part of forest ecosystem and it has certain functions that support ecosystem sustainability. Utilization of NWFPs is a sustainable use or utilization of by-products from trees or other forest products. The present study aimed to obtain basic information on the NWFPs species that cultivated in Gempolan Village. Therefore, the species density, relative density, frequency, relative frequency, and important value index was calculated. In addition, the utilization of NWFPs species was described based on the interview. Field observation was conducted in 38 community forest by making plots 40 × 25 m2. Furthermore, interview was conducted with the owner of those community forests to obtain information on the NWFPs utilization. The results showed that community forest management in Gempolan Village applies an agroforestry system with a random mixture and alternate row-cropping pattern. NWFPs can be classified as their function, namely as food, medicinal plant, animal feed, and spices/condiments. Most of the NWFPs were only used to meet their own needs. NWFPs that produces from community forest in Gempolan Village was dominated by multi-purposes tree species (fruits) such as durian, avocado, jengkol, petai, pakel, sawo, melinjo, jackfruit, and breadfruit.

Compressive and tensile strength of aeolian sand stabilized with porcelain polishing waste and hydrated lime

The improvement of sandy soils by incorporating new stabilizing agents in a physical and/or chemical process has become the subject of many studies in recent decades. In addition, the use of industrial wastes in this process can bring significant benefits to the environment and savings in natural resources. This work aims to evaluate the implications of incorporating porcelain polishing waste (PPW) and hydrated lime on the mechanical properties of an aeolian dune sand from the city of Natal/RN. Tests of unconfined compressive strength and split tensile strength were performed on compacted soil specimens with different contents of PPW (10%, 20% and 30%), hydrated lime (3%, 5% and 7%) and relative densities (25%, 50% and 75%). To evaluate the effects of each factor, the Response Surface Methodology with Central Composite Design was used. The results have shown that all three factors have a positive effect on the response variables. The highest strengths were obtained in regions combining high values of relative density and PPW content and an optimum lime content was found. An inversely proportional correlation and good fit to the experimental data was obtained between the strength values and the porosity/binder index (η / Biv). The strength gains were attributed to densification of the soil structure and cementation of the particles by the compounds formed in the reaction between lime and PPW. The results also showed an increase in the strength with curing time, indicating a pozzolanic activity of the mixtures.

Interpretation of CPTu and SPT data about sandy soils in the Plovdiv region

CPTu (Piezocone Penetration Test) and Penetration tests – SPT (Standard Penetration Test) are the most used in situ tests in order to map a soil stratigraphy and determine the geotechnical parameters of construction soils. A comparison has been made between the relative density values obtained on the basis of the two types of field trials. The soils examined are classified according to well-established classification diagrams. The sandy soils are described in the range of dense to very dense. They have good strength and deformation characteristics – with a high friction angle and high Young’s modulus but the presence of a high level of groundwater is a prerequisite for their liquefaction under dynamic impacts.

Значимость нарушений ретинальной микроциркуляции как предикторов прогрессирования глаукомной оптической нейропатии

Purpose – to assess the significance of retinal microcirculation disorders in progression of glaucomatous optic neuropathy (GON). Material and methods. In this 2-year prospective study 85 patients (124 eyes) the vessel density of the superficial parafoveal plexus (VD parafovea) and peripapillary retina (VD ppr) were measured with optical coherence tomography angiography, peripheral resistance index (RI) and blood flow velocity of the posterior short ciliary arteries (PSCA) and the central retinal artery (CRA) were studied by color Doppler flow mapping method. The predictor properties of each indicator were calculated from the area under the ROC curve (AUC). Results. The results of the study revealed a high significance of the values of relative density of the superficial plexus vessels in the parafoveolar region (VD parafovea AUC 0.70 ± 0.07), and the relative density of the microvasculature of the optic nerve head (ONH) and peripapillary retina (VD ppr 0.715 ± 0.07) as predictors of the progression of GON. Keywords: primary open-angle glaucoma, glaucomatous optic neuropathy, ocular blood flow, optical coherence tomography angiography

Phyto-sociological survey of weeds in direct seeded rice (Oryza sativa L.)

Field observation was carried out at Melbhuvanagiri block, (Valayamadevi, Periyanarkunam, AgaraAlambadi and Periyakuppam villages), Cuddalore district during 2020 to determine the phytosociologicalcharacters of weeds in direct seeded rice fields. The composition of the weed species in the fields wasevaluated by randomly throwing 0.25 m2 quadrate in 10 different locations in each village. Frequency,density, abundance and their relative values were calculated. Highest relative frequency, relative density,relative abundance and importance value index was observed with Echinochloacolona (L.)Link amonggrasses, Cyperus difformisL. among sedges and Eclipta alba (L.) Hassk among broad leaved weeds in all theobserved villages of direct seeded rice fields. Diversity indices were worked out for each village, amongthem Periyanarkunam village recorded the highest diversity indices (Shannon index (H’) of 2.234, Simpsonindex (D) of 0.873 and Evenness index (E) of 2.070) in direct seeded rice. Hence weeds were prominent inPeriyanarkunam village than all the observation sites.

Enhancement of the Optical and Dielectric Properties at Low Frequency of (Sr1-xCax)5Ti4O13, (0 ≤ x ≤ 0.06) Structure Ceramics.

Low loss Ruddlesden-Popper (RP) series, i.e., (Sr1-xCax)5Ti4O13, 0.0 ≤ x ≤ 0.06, has been synthesized by a mixed oxide route. In this work, the substitution of Ca2+ cation in Sr5Ti4O13 sintered ceramics was chosen to enhance the structural, optical, and dielectric properties of the product. It was found that the Ca2+ content has significant effects on enhancing the dielectric properties as compared to Mn and glass additions. It was observed that the relative density, band gap energy, and dielectric loss (tangent loss) increase while relative permittivity decreases along with Ca2+ content. High relative density (96.7%), low porosity, and high band gap energy (2.241 eV) values were obtained in (Sr1-xCax)5Ti4O13, 0.0 ≤ x ≤ 0.06 sintered ceramics. These results will play a key role in the application of dielectric resonators.

Community Structure and Distribution of Coleoptera Soil IPM and Non IPM Upland Vegetable Agricultural Areas in Two Villages in Kabanjahe

The concept of Integrated Pest Management (IPM) is an effort developed by the government in order to reduce the use of pesticides in the agricultural sector. In the development of agriculture in Kabanjahe, both Non-IPM (Non Integrated Pest Management) and IPM (Integrated Pest Management), research is needed to determine the community structure and distribution of soil fauna, including soil coleoptera, and to determine the effect of soil physical and chemical factors on soil coleoptera community structure in the highland vegetable farming area of Kabanjahe district. Karo Regency. Determination of sampling points in this study was carried out using the "purposive random sampling" method, in two agricultural areas, in two villages, namely Sumber Mufakat and Gung Negri, Non-IPM agricultural land areas and IPM agricultural areas. While the active coleoptera sampling of the soil surface was carried out using the Pit Fall Trap method, and the Quadratic and Hand Sorting methods for Coleoptera that live in the soil. The results showed that the number of types and population density of coleopteran soil was more / higher in the area. IPM agriculture. The highest density and relative density values in the research area were the genus Callosoma for the IPM and Non-IPM lands of Sumber Mufakat Village and the IPM of Gung Negri Village, while for the Gung Negri Non-IPM land the genus Scapidium and the genus Tenebrio.

Effect of TiB2 particles on microstructure and mechanical properties of B4C–TiB2 ceramics prepared by hot pressing

B4C-20 wt% TiB2 ceramics were fabricated by hot pressing B4C and ball-milled TiB2 powder mixtures. The effects of the TiB2 particle size on the microstructure and mechanical properties were investigated. The results showed that the TiB2 particle size played an important role in the mechanical properties of the B4C–TiB2 ceramics. In addition, SiO2 introduced by ball milling was beneficial for densification but detrimental to the mechanical properties of the B4C–TiB2 ceramics. The typical values of relative density, hardness, flexural strength, and fracture toughness of the ceramics were 99.20%, 35.22 GPa, 765 MPa, and 7.69 MPa m1/2, respectively. The toughening mechanisms of the B4C–TiB2 ceramics were explained by crack deflection and crack branching. In this study, the effects of high pressure and temperature caused liquefying SiO2 to migrate to the surface of B4C–TiB2 and react with diffused carbon source in the graphite foil to form a 30 μm thick SiC layered structure, which improved the high-temperature oxidation resistance of the material. The unique SiC layered structure overcame the insufficient oxidation resistance of B4C and TiB2, thereby improving the oxidation resistance of the ceramics under high-temperature service conditions.

Abundance of invasive alien species of teklan (Ageratina riparia (Regel) R. M. King & H. Rob.: Asteraceae) on floor vegetation in “Eka Karya” Botanical Garden, Bali

Ageratina riparia is an invasive alien species that get a particular attention in “Eka Karya” Bali Botanical Garden. This study aims to determine the abundance of invasive alien species A. riparia on forest floor vegetation in “Eka Karya” Bali Botanical Garden, and the factors that influence its abundance. Ageratina riparia is an invasive herb that can disrupt the balance of the ecosystem. The advantages of this plant in reproducing and adapting to the environment, make this plant very easy to grow and develop in a habitat. The purposive sampling method was used with the plot that placed systematically. The research area divided into five research stations with 10 plots (2 x 2 m) for each station. Vegetation data were analyzed to determine the density, relative density, frequency, relative frequency, and important value index (INP), then completed with Shannon-Weiner diversity index (H'), dominancy index (C), evenness index (E) and visualization abundance of species A. riparia of with Non-metric Multi Dimensional Scaling (NMDS). Environmental data is calculated analyses in Detrended Correspondence Analysis (DCA). The results showed that A. riparia at station 1 (Kawasan Kepala Burung) had an INP of 62.50%, station 2 (Taman Usada) with an INP of 52.40%, station 3 (Taman Cyathea) with an INP of 89.09%, station 4 (middle open area) with an INP of 110.25%, and the highest is at station 5 (Taman Upacara Panca Yadnya) with an INP value of 118.92%. The presence of A. riparia can be influenced by all environmental factors measured such as air humidity, soil moisture, soil pH, air temperature and soil temperature, altitude, land slope, and light intensity.

Developing Predictive Models of Collapse Settlement and Coefficient of Stress Release of Sandy-Gravel Soil via Evolutionary Polynomial Regression

The collapse settlement of granular soil, which brings about considerable deformations, is an important issue in geotechnical engineering. Several factors are involved in this phenomenon, which makes it difficult to predict. The present study aimed to develop a model to predict the collapse settlement and coefficient of stress release of sandy gravel soil through evolutionary polynomial regression (EPR). To achieve this, a dataset containing 180 records obtained from a large-scale direct shear test was used. In this study, five models were developed with the secant hyperbolic, tangent hyperbolic, natural logarithm, exponential, and sinusoidal inner functions. Using sand content (SC), normal stress (σn), shear stress level (SL), and relative density (Dr) values, the models can predict the collapse settlement (∆H) and coefficient of stress release (CSR). The results indicated that the models developed with the exponential functions were the best models. With these models, the values of R2 for training, testing, and all data in the prediction of collapse settlement were 0.9759, 0.9759, and 0.9757, respectively, and the values of R2 in predicting the coefficient of stress release were 0.9833, 0.9820, and 0.9833, respectively. The sensitivity analysis also revealed that the sand content (SC) and relative density (Dr) parameters had the highest and lowest degrees of importance in predicting collapse settlement. In contrast, the Dr and SC parameters showed the highest and lowest degrees of importance in predicting the coefficient of stress release. Finally, the conducted parametric study showed that the developed models were in line with the results of previous studies.

Mangroves and the Sustainability of Longtail Shad Fish (Tenualosa macroura) in Riau Province Water, Indonesia

Mangroves are crucial to fisheries as nurseries; they can be used as spawning and feeding grounds for fish, including Longtail Shad fish (Tenualosa macroura). The objective of the study was to analyze the mangrove vegetation used as Longtail Shad fish spawning ground. It was carried out from January to May 2021, using a checkered line method with six sampling stations. Each station was placed in three transects with three plots for each transect. Density, relative density, frequency, relative frequency, dominance, relative dominance, and importance value index were included in the vegetation analysis. There were 13 true mangrove types and 1 mangrove associate type at the study locations. The highest mangrove density was found at Station 3 with 3300.48 Ind/Ha, categorized as good. The highest mangrove coverage was found at Station 2, with an exceptionally dense category (76.34%). The regression analysis revealed a substantial relationship between density and mangrove and the water salinity at a 0.002 significance value (<0.05). Based on the gut content analysis in establishing the fish's eating habits, the type of food consumed by the Longtail Shad fish was mostly mangrove litter, representing 44.66% of the total stomach contents. The result of the study clearly shows that mangroves are crucial for Longtail Shad fish. A good mangrove ecosystem will provide good water quality for the migration process of longtail shad fish and produce mangrove litter as fish food. Mangrove ecosystem management can support the management of Terubuk fisheries.

SDS SURFACTANT EFFECTS ON STABILITY AND THERMOPHYSICAL PROPERTIES OF Al2O3–WATER BASED NANOFLUIDS

Nanofluids have been considered as new potential heat transfer fluids, but there are controversial results about the stability and thermophysical properties of nanofluids in literature. In this experimental study, nanofluids at different aluminium oxide (Al2O3) volume fractions (0.3–1.1%) and sodium dodecyl sulfate (SDS) surfactant weight fractions (0.2–0.8%) were prepared by utilizing the two-step method. Stability of the obtained nanofluids was determined according to the sedimentation method, zeta potential and average particle size analysis. Density, viscosity and thermal conductivity of the nanofluids were measured experimentally from 298 K to 338 K. According to the results, the nanofluids prepared with 0.2% SDS began to collapse within a few minutes. However, it was observed that the stability of nanofluids prepared with 0.4% SDS, 0.6% SDS, and 0.8% SDS changed with the particle concentration. Besides, relative density values of nanofluids were found to be independent of temperature for each particle concentration. While relative viscosity of nanofluids increased with temperature, the highest relative thermal conductivity values of nanofluids with different weights of SDS were achieved at different temperatures. In general, relative thermal properties tend to increase with an increase in particle concentration. It has been observed that the stability and dispersion of nanofluids have a high effect on thermophysical properties.

Pengaruh Tinggi Muka Air Terhadap Deformasi Tanah Terlikuefaksi

Liquefaction occurs in saturated loose sandy soils that experience an increase in pore water pressure due to the propagation of earthquake waves to the ground surface. This phenomenon raises various questions such as how the groundwater level can affect the occurrence of liquefaction events at different earthquake strengths. The purpose of this study was to determine the effect of groundwater level on liquefaction-prone soils at different seismic peak acceleration values and the effect of relative density (Dr) values on liquefaction-prone soils with variations in groundwater level and earthquake acceleration. In this study, a sample of Jono Oge sand soil was used from the occurrence of liquefaction that met the gradation criteria. The soil was separated through the #8 sieve and retained #100. The modeling technique is carried out with several variables such as the ratio of groundwater level (Hw/Hs) of 25%, 50%, 75%, and 90%, relative density (Dr) 30%-40% and 40%-50%, and at different peak accelerations of 0.3g and 0.4g. The modeling test uses a sieve shaker for earthquake vibrations.. The results of the study show that the difference in groundwater level affects the subsidence of liquefied soil where the settlement will be accure greater in the ratio of the groundwater level (Hw/Hs) and the peak acceleration is greater and vice versa, the difference in relative density (Dr) also affects the magnitude of the the settlement where the lower the Dr value for Hw/Hs and the greater the peak acceleration, the greater the settlement will be occure.

INVESTIGATION OF THE LOAD-BEARING CAPACITY OF Co-Cr LATTICE STRUCTURES FABRICATED BY SELECTIVE LASER MELTING

Additively manufactured Co-Cr lattice structures are promising choices especially in medical applications. This study involves the designing and fabrication of a novel lattice structures with FCCZZ (face-centered cubic with exterior and interior vertical struts) unit cell topology. The manufacturability by selective laser melting (SLM) and the load-bearing capacity of this structure were examined by utilizing scanning electron microscope (SEM) observations and uniaxial compression tests. The samples with FCCZ (face-centered cubic with vertical struts) structures were also produced and analyzed for comparison. The designed lattice structures were successfully manufactured by SLM even though an approximately 1.5-2% increase in the theoretical relative density values was observed. The novel FCCZZ samples exhibited superior performance in terms of the load-bearing capacity compared to FCCZ samples by possessing 17% higher specific strength value.

Zr-bearing powder metallurgy binary Ti alloys: Fabrication and characterisation

Zirconium is an ideal alloying element to be added to titanium for biomedical applications due to its non-toxic behaviour and high solubility. In literature, binary Ti–Zr alloys have primarily been manufactured via casting, while powder metallurgy has been partly ignored even though of its intrinsic advantages. Moreover, the tensile properties of Ti–Zr alloys, and so their work hardening behaviour, has not been properly understood. Consequently, this study investigated the effects that lean additions of Zr have on the microstructure and properties of powder metallurgy binary Ti–Zr alloys produced by uniaxial pressing plus sintering. It is found that the incremental addition of Zr reduces the compressibility and enhances the densification, resulting in comparable relative density values for different Zr contents. The addition of Zr leads to the formation of a lamellar microstructure, which is progressively refined by further addition of Zr. Therefore, the tensile strength and hardness increase with the incremental addition of Zr, while the ductility initially increases and then decreases. Although the studied Ti–Zr alloys have similar work hardening, their actual behaviour is directly dictated by the microstructural features.

Vegetation analysis of 10 urban forests in the city of Banda Aceh, Indonesia

Abstract. Dharma W, Zakaria R. 2022. Vegetation analysis of 10 urban forests in the city of Banda Aceh, Indonesia. Biodiversitas 23: 4131-4137. The vegetation of urban forests is strongly influenced by the composition of trees planted in the forest area. In order to maintain its sustainability, complete vegetation data is needed as a basis for good urban forest management. The purpose of this study was to identify the species diversity of trees in 10 urban forests in the city of Banda Aceh. The study was conducted using the Cruising method with the count of all vegetation species found in urban forests in the city of Banda Aceh. Data analysis was done by the vegetation analysis method through the calculation of diversity index (H'), Relative Frequency (RF), Relative Density (RD), Relative Dominance (RB), and Importance Value Index (IVI). The results showed that the tree component of the area was composed of 50 tree species representing 2218 individuals. The highest IVI value was found in Samanea saman with an IVI value of 67.95, and the lowest was in Tamarindus indica species with an IVI value of 8.16. The diversity index in the observed urban forests was low, with the highest index in Tibang forest at only 0.37. In order to increase plant diversity in urban forests in the city of Banda Aceh, plant species enrichment is needed. It is expected to increase ecological functions in the surrounding environments.

Towards biomimetic, lattice-based, tendon and ligament metamaterial designs

The engineering of tendon and ligament tissue biocompatible restoration materials constitutes a long-standing engineering challenge, from the chemical, biological and mechanical compatibility analysis and design perspective. Their mechanics are inherently anisotropic, exceeding the potential limits of common, non-architected engineering materials. In the current contribution, the design of advanced material or “metamaterial” architectures that can emulate the mechanical properties observed in native tendon and ligament tissues is analytically, experimentally, and numerically investigated. To that scope, anisotropic metamaterial designs that are based on rectangular cuboid architectures with and without inner body-centered strengthening cores are considered. Thereupon, the metamaterial design specifications required for the approximation of the highly anisotropic tissue performance, namely of the characteristic normal, shear and Poisson's ratio attributes are studied. It is shown that certain strengthened, anisotropic body-centered cuboid lattice architectures allow for substantial effective metamaterial stiffness along the primal tissue loading direction, upon a rather low shear loading resistance. The previous mechanical attributes come along with Poisson's ratio values well above unity and moderate relative density values, furnishing a combination of material characteristics that is highly desirable in restoration praxis. The analytically and numerically guided anisotropic metamaterial performance is experimentally reproduced both for the case of uniaxial and shear loads, using a microfabrication stereolithography additive manufacturing technique. The obtained scanning electron microscopy images highlight the fabrication feasibility of the identified metamaterial architectures, in scales that are directly comparable with the ones reported for the natural tissues, having feature sizes in the range of some 10ths of micrometers and elastic attributes within the range of clinical observation.

Shade tree pattern of highland coffee plantation and coffee production in Aceh Tengah, Indonesia

Coffee is one commodity has high economics market that cultivated by farmer mainly in the high elevation area. The economics and ecological function of coffee plantations have to be worked in the area plantation, so formulation combination between coffee and forest tree is important. The research aimed to identify the tree species composition of a shade tree in a coffee plantation. Some plot sized 50 m x 50 m was distributed based on lands properties of farmers. Density, frequency, and tree spacing were measured to get basal area, relative density, relative frequency, and important value index. A more in-depth statistical analysis was performed using SPPS to determine the significance of the relationship between density and frequency with coffee productivity. The relationship between tree spacing planting, basal area, and shade trees’ density with Arabica coffee production is a strong enough relationship is the density variable. While the relationship between regular and disordered planting spacing variables with coffee production is strong. The relationship between basal area, density, and coffee production is very weak.

Mechanical attributes and wave propagation characteristics of TPMS lattice structures

The current work investigates the mechanical properties and wave propagation characteristics of sheet and solid type triply periodic minimal surface structures (TPMSs), including the gyroid, primitive, diamond, and IWP lattices over a broad range of relative density values. Their effective Young's and shear moduli, as well as their Poisson's ratio are characterized for relative densities in the range 0.15–0.6. It is found that higher-order polynomial expressions can robustly capture the entire metamaterial design space for both sheet and solid-type structures, with the mechanical performance of solid-type TPMS lattices to substantially differ from the corresponding sheet-type designs. The numerical results are experimentally verified using 3D-printed TPMS specimens. The static attributes are thereafter used to investigate the effect of the relative density and propagating direction on the long-wavelength wave characteristics of sheet and solid type TPMS lattices. It is found that the shear and longitudinal phase velocities differ the most and least in well-defined propagation directions with an in-plane angular difference of 45° for both sheet and solid-type TPMS lattices. Moreover, the primitive-type TPMS lattices are found to exhibit the highest anisotropy among the considered structures.

Linking regeneration niche to monodominance in biodiverse tropical forest landscapes

AbstractAimsAlthough monodominance has attracted the attention of ecologists for many decades, few studies have devoted attention to how abiotic factors could influence the occurrence of monodominant forest patches at the biome scale. Here, we assessed whether the occurrence of monodominant forest patches of Moquiniastrum polymorphum (Less.) G. Sancho (Asteraceae), an early‐successional tree species with wind‐dispersed seeds, could be predicted using optimum germination temperature and past deforestation. We also verified under what edaphic and climatic conditions the species could reach monodominance.LocationThe Atlantic Forest, Brazil.MethodsWe estimated optimum germination temperature across the species’ geographic range as a function of annual mean temperature based on the results of germination tests available in the literature. Past deforestation (a proxy for suitable habitat for the species’ dispersal and establishment) around monodominant forest patches was estimated by calculating the forest cover in 1985. We also modeled the upper limit of dominance (relative abundance) as a function of climatic and edaphic variables considered important for the species’ establishment.ResultsThe results showed that the probability of occurrence of monodominant forest patches is statistically null in places where germination can take more than 10 days and the landscape had more than 20% forest cover. Relative density values for the monodominant condition (&gt; 60%) occurred only in warmer regions with infertile soils and median precipitation conditions (ca. 1,075–1,700 mm per year) in the Atlantic Forest.ConclusionWe conclude that only under optimal conditions of germination and dispersal (i.e., regeneration niche) does monodominance occur. This highlights germination traits as an important mechanism for regulating monodominance. In addition, the approach used to predict regions with optimum germination temperature has further implications for understanding species abundance and distribution more generally.