Block Volume Research Articles

Synthesis, Characteristics and Thermally Induced Self-Assembly of Silicon-Based Thermo/Photo-Responsive Block Copolymers Prepared from Monomer Bearing Paired Side-Chain Azo Mesogens Using RAFT Process

Novel silicon-based liquid crystalline (LC) monomer (CASPA) and corresponding Poly(MMA)-b-Poly(CASPA) diblock copolymers (DBCs) containing symmetric azobenzene mesogens in the side chain were successfully synthesized by coupling reaction and reversible addition-fragmentation chain transfer (RAFT) polymerization, respectively. Block copolymerization by RAFT proceeded with well-controlled manner in anisole solution involving new CASPA monomer, Poly(MMA)-RAFT macroinitiator and AIBN initiator, yielding Poly(MMA)-b-Poly(CASPA) DBCs with excellent control over molecular weights (Mw/Mn ≤ 1.39) and compositions. Chemical structures and properties of CASPA and Poly(MMA)-b-Poly(CASPA) were extensively studied using 1H NMR, FTIR, GPC, DSC, POM, AFM and GISAXS. The CASPA exhibited enantiotropic liquid crystallinity with nematic four-brush schlieren texture, while DBCs showed monotropic liquid crystallinity with batonnet textures of smectic A phase. All DBC films exhibited photochemical trans-cis isomerization and photoinduced phase transition from mesophase to isotropic phase under UV irradiation. Morphologies of DBC thin films under thermal annealing depended on volume ratio of building LC block relative to Poly(MMA) segment, DBC-2 containing approximately equal block volume fractions self-assembled into lamellar nanostructure with domain-spacing of 34 nm, whereas DBC-3 and DBC-4 possessing higher LC contents (65 wt% and 72 wt%) formed highly ordered hexagonal cylindrical nanostructures with domain-spacing ranging from 37 to 39 nm as evidence by AFM and GI-SAXS, conforming with the self-consistent field theory.

Analysis of Infiltration and Runoff Based on the Volume of Storage Spaces in Storage Permeable Blocks

Recent climate change has led to an increase in total rainfall in spite of a decrease in the number of rainy days. In addition, the increase in impervious surfaces due to urbanization has resulted in greater surface runoff, resulting in urban flooding and flash floods. To address this issue, low-impact development techniques have been introduced to improve water cycle health within watersheds. Permeable pavements, which serve as roadways while reducing impervious surfaces, have been introduced in new towns and development zones. However, most performance evaluations were based solely on the permeability coefficient of the pavement, with limited research on the water cycle performance of the entire permeable pavement system, including the subbase layer. Therefore, this study aims to analyze the effects of the porosity storage volume of joint-type permeable blocks with storage spaces under the same conditions for two types of permeable blocks. The results showed that increasing the porosity storage volume reduced the equilibrium runoff rate by 70%, and increased the runoff time delay by 2 to 2.5 times.

Estimation of Excavator-Automobile Complex Productivity at Changing of Engineering and Geological Conditions

In open pit mining of solid minerals, loading of rock mass from the face is usually carried out without moving the excavator until the dump truck is fully loaded. To ensure that the dump truck body is filled at maximum excavator productivity, the volume of rock mass in a single removed face block should correspond to the capacity of the body, taking into account the loosening of rock during excavation. The article considers the influence of such factors as the minimum radius of excavator digging at the level of its placement, the step of excavator movement, the coefficient of rock loosening during its removal from the massif when working in the mining face, on the volume of downhole block and the angles of excavator rotation for unloading, taking into account the safe operation of excavation-loading and transportation equipment. As an example, the excavator Komatsu PC1250 backhoe is considered when paired with a dump truck BELAZ 7531 (240 tons) when loading coal by top and bottom digging, with the dump truck below the level of the excavator from the side of the slope across the strike of the seam.

Anatomical assessments of injectate spread stratified by the volume of the intertransverse process block at the T2 level

BackgroundThis cadaveric study aimed to analyze injectate spread to target nerves during a single-injection, ultrasound-guided intertransverse process block.MethodsAn ultrasound-guided intertransverse process block with three different injectate volumes was administered to...

Semi-Automated rock block volume extraction from high-resolution 3D point clouds for enhanced rockfall hazard analysis

Rockfalls are critical landslide phenomena affecting human activities, with risk assessment based on hazard evaluation and potential impacts on exposed elements. Traditional methods for estimating unstable rock block volumes require direct measures often in hard-to-reach areas, hazardous, with time consuming approaches. This study introduces a semi-automatic method for estimating the most probable volume of the unstable blocks using open-source software (CloudCompare) to process 3D Point Cloud (PC) data obtained via Terrestrial Laser Scanning (TLS). The application area is a rock slope in a coastal sector of the northern Sicily (Italy) affected by frequent rockfalls phenomena. Both traditional field surveys and TLS were employed to characterize discontinuities and perform kinematic analyses. Volumes of already fallen blocks were directly measured, while unstable blocks were identified and volumetrically assessed using the PC-based procedure. Statistical analysis revealed that both created datasets conform to lognormal distributions; direct measurements show a better fit due to a larger sample size. Moreover, direct and indirect approaches were applied for recognition of main discontinuity sets influencing block detachment through planar sliding, toppling, and wedge failure. The proposed method offers a safer, more efficient alternative for rock mass characterization. Integration of traditional and remote sensing techniques facilitates accurate hazard evaluation, enhancing risk reduction strategies in vulnerable areas.

Analisis Kemampuan Berpikir Kritis dalam Menafsirkan Soal Cerita Matematika pada Siswa Kelas 5 SDN Sukaasih 1 Kabupaten Tangerang

Mathematics is a subject that requires high critical thinking skills to be able to understand problems. Especially for working on questions in story form. Therefore, this research aims to analyze the critical thinking abilities of class 5D students in interpreting mathematics story problems on block volume material. This research uses qualitative research with a descriptive approach. The subjects in this research were 15 students in class 5D at SDN Sukaasih 1. Data collection techniques use tests, interviews and documentation. from test results, interviews, and documentation. This research data analysis uses data reduction, data presentation, and drawing conclusions. The research results showed that out of a total of 15 students, 2 students had high critical thinking abilities, 2 students had moderate critical thinking abilities, and 11 students had low critical thinking abilities. Based on the research results, the researcher concluded that the critical thinking abilities of class 5D students at SDN Sukaasih 1 were in the low category. Therefore, the critical thinking skills of class 5D students at SDN Sukaasih 1 still need further training so that they can be improved.

Block Volume and Shape: Comparison of Calculation Methods and Investigation of Possible Relationships

Block Volume and Shape: Comparison of Calculation Methods and Investigation of Possible Relationships

Pengaruh Media Visual Tiga Dimensi terhadap Hasil Belajar Matematika pada Materi Volume Kubus dan Balok Kelas V SD

This research aims to determine the effect of three-dimensional visual media on mathematics learning outcomes in the volume of cubes and blocks for class V SD Negeri 060877 Medan. The type of research is quantitative research with quasi-experimental methods. The population in the study was all fifth grade students with a total of 45 students. The sample for this research was class VA totaling 22 students as the experimental class and class VB totaling 23 students as the control class. The data collection technique uses a mathematics learning outcomes test. The data analysis technique used is data description, trend testing, requirements testing, and hypothesis testing using the t-test. Based on the results of the t-test, there is a positive and significant influence on three-dimensional visual media on mathematics learning outcomes in the material volume of cubes and blocks for class V SD Negeri 060877 Medan with a value (tcount>ttable) namely (14.33>1.67) on significance level 5 percent. This means that three-dimensional visual media can influence mathematics learning outcomes in the volume of cubes and blocks.

A series of regression models to predict the weathering index of tropical granite rock mass

In the recent past, several weathering indicators have been developed to describe its state of weathering. The state of rock weathering is a useful indicator to estimate the integrity of tropically weathered rock material and mass which weatherability plays an important role in a tropical region. Through a ground assessment tool, the strength and durability of the rock mass could be estimated and complex or adopted to simplify the early prediction of the complex engineering parameter. This paper presents several models of the Weathering Index (WI) using selected significant parameters using statistical analysis. For this purpose, several sites have been chosen to represent granitic rock mass. Forty (40) numbers of samples were collected and tested comprising from four (4) sites in Malaysia. Several laboratory tests have been conducted such as Point Load Index (Is(50)), dry density, Slake Durability 1 (SD1), Slake Durability 2 (SD2) and moisture content. The field and laboratory data sets are used to determine the WI by using simple regression and MLR analysis Significant parameters found to be useful in determining the WI are selected namely SD1, dry density, Is(50), and block volume. These parameters were selected based on stepwise analysis using Statistical Package for the Social Sciences (SPSS). Following the models’ implementation, the models were evaluated and the best prediction model was selected after considering statistical coefficients, such as coefficient of determination (R2), variance account for (VAF), and root mean squared error (RMSE), as well as utilizing a straightforward ranking approach. The findings of this study could contribute to the more accurate prediction of WI using a more simplistic field and laboratory parameters. Therefore, the WI is useful during the initial stages and planning of rock excavation work and provides a good description of weathering grade and rock mass properties, which will affect excavatability in granitic areas.

Deep-Seated Landslide and Rockfalls Threatening the Village of Pietracamela in Central Italy: Deciphering Phenomena from Interferometric Synthetic Aperture Radar and Point Cloud Analysis

Landslides represent a major problem in human activities, especially in the proximity of cities or infrastructure. In this paper, we present the peculiar case of Pietracamela, Italy. Pietracamela is a small village located in the Central Apennines, a few kilometers north of the Gran Sasso Mountain. The peculiarity of the case study is the fact that the village is simultaneously affected by two different types of slope instabilities. The southwest sector, representing the historical part of the village, has been affected by large rockfalls generated from the “Capo le Vene” cliff located in the south of the village. The northeastern sector of the village represents the most recent urbanized area and is involved in a deep-seated landslide that, in the last decades, has damaged buildings and infrastructure. In this context, we have used two different types of remote sensing techniques to study the two phenomena. The rockfall area has been surveyed through the use of an Unmanned Aerial Vehicle (UAV) that allowed the definition of main joint sets and the volume of blocks associated with the most recent (2011) rockfall event. Three main joint sets have been highlighted, which are responsible for the failure of the “Capo le Vene” cliff. The volume of blocks that failed during the last rock failure in 2011 ranged from a few to 1500 m3. The deep-seated landslide has been studied by analyzing borehole data and 20 years of InSAR data from ERS1/2, ENVISAT, COSMO-SkyMed, and SENTINEL-1. It has been highlighted by InSAR analysis that the northeast sector of the village shows a perfectly linear displacement trend that generates movements up to about 230 mm (about 1 cm/year).

Ionic liquid mediated one-step perpendicular assembly in block copolymer thin films for ultrafiltration membrane applications

The rapid rise of oil and gas, petrochemical, food processing, and pharmaceutical industries has added a complex mixture of contaminants like oil, particulates, metals, and other organic compounds to wastewater. Multipurpose membranes with precise pore structure can offer a solution to this problem and block copolymers (BCP) can be used to achieve such structures. Achieving vertical assembly of BCP domains provides a perfect template for developing uniform through film channels for separation and transport of material, besides being useful for the rectification of defects in photolithography patterns. Producing such morphologies may require extensive film/substrate processing and is not always feasible for scale-up. With this article, we demonstrate a facile solution casting method to induce vertical domain assembly in as-cast diblock copolymer thin films in the presence of an ionic liquid (IL) additive that preferentially segregates to one block and neutralizes interfacial interactions. We also show the tunability of domain sizes by controlling the additive concentration. These vertically aligned morphologies are important for the development of next-generation lithographic techniques and form excellent templates for ultrafiltration membranes with uniform pore sizes. This article demonstrates how IL additives can be used to obtain stable non-equilibrium morphologies in as-cast BCP films and the effect of BCP molecular mass, block volume fractions, and IL content on self-assembly.

Rockfall susceptibility analysis of the “San Michele Arcangelo” historic trail (Central Italy) based on virtual outcrops and multiple propagation models

The “San Michele Arcangelo” historic trail (Aurunci Regional Park, central Italy), located along the southern slope of Mt. Altino, which is highly prone to rockfalls, is hiked every year by thousands of faithful on pilgrimage who are exposed to such kinds of instabilities. To contribute to a better understanding of the condition and evolution of such phenomena, providing a susceptibility scenario able to support the adoption of mitigation measures, a specific analysis was completed based on field and literature data. Three-dimensional virtual outcrop models were obtained through both photogrammetric and iPad Pro LiDAR surveys to derive geomechanical features of outcropping rocks and estimate potential detaching block volume. Possible mechanisms of detachment were then analyzed using the Markland test method. Susceptibility to rockfall propagation and block deposition was analyzed using GIS processing and rockfall propagation simulations based on deterministic/stochastic models. Such models consist of a combination of a deterministic algorithm able to simulate the physics of rockfall movement during propagation and a stochastic treatment of input parameters based on random sampling within defined interval. Two different rockfall simulations were compared in this study using the Rockyfor3D™ (ecorisQ Association) software and the newly developed RocFall3© (RocScience) code. The use of iPad Pro LiDAR survey provides accurate and high-resolution point clouds, with high speed of acquisition and real-time processing of data. Discontinuity sets identified from 3D models have represented the input for kinematic analyses of slopes, allowing to identify potential failure mechanisms among wedge and planar sliding or toppling. Rockfall simulations indicate the potential for rock blocks propagation and deposition over the whole study area. Comparing the results of rockfall simulations with the geomorphological map of the area it is evident the control exerted by the hydrographic network on rockfall propagation as demonstrated by the presence of screes and slope deposits along the main channels. Understanding the potential susceptibility to both propagation and deposition of rock blocks along the trail provides useful indication for the assessment of appropriate mitigation measures to realize for the safer touristic fruition of the site.

Worm‐like ordered mesoporous carbon from liquefied wood: Morphological manipulation by varying hydrothermal temperature

AbstractThe hydrothermal/soft templating method is an effective way to synthesize ordered mesoporous carbon (OMC), yet the mechanism of this strategy is not well illustrated. Herein, a hydrothermal temperature‐controlled approach is developed to precisely synthesize OMCs with well‐defined morphologies from liquefied wood (LW). As the hydrothermal temperature increases from 130 to 210°C, the hydrophilicity of the hydrophilic blocks decreases accompanied by the increase of the relative volume of the hydrophobic block, resulting in the packing parameter p of micelles changing from p ≤ 1/3 to 1/3 < p < 1/2, which transforms the micelle's structure from spherical to cylindrical. Additionally, accelerated nucleation occurred with the increased hydrothermal temperature. When the rate of nucleation is matched to the self‐assembly of the composite micelles, the composite micelles grow into worm‐like morphology and an ordered p6m mesostructure. This hydrothermal temperature‐controlled strategy provides a straightforward and effective approach for synthesizing OMCs with various morphologies from LW, addressing the previously insufficiently elucidated micelle formation mechanism in the hydrothermal/soft templating method.

A New Analytical Solution for Calculating Rock Block Volume

The study of rock slope stability and evolution suffers from many uncertainty factors related to block size and shape, and slope morphology. While nothing can be done to remove the aleatory component of these uncertainties, efforts in reducing the epistemic ones are desirable. This research aims to propose a new analytical solution for calculating rock block volume in the case of three discontinuity sets whose orientation and true spacing are known. Researchers and practitioners can take advantage of such a correct analytical formula thanks to its easiness of use: guidelines based on stereogram are provided in order to explain how to obtain the required input data. The correctness of the equation is demonstrated by comparing the results of the new solution applied to 12 theoretical blocks with those obtained with 3DEC (Itasca Consulting Group). Also, the differences with respect to results obtained with the well-known Palmstrøm’s formula are reported. The new methodology is applied to the case study of Elva valley road (Northern Italy), which is overhung by steep rocky cliffs and is subject to the consequences of frequent rockfall phenomena. The results are used to discuss the proposed method’s applicability: while it is evident that such a formula is not able to compete with the great potentiality of DFNs, this user-friendly tool can quickly and at no cost assess rock block volume in rockfall or rock slope stability studies.

Self‐assembly and degradation of photolabile diblock bottlebrushes

AbstractAqueous self‐assembly of amphiphilic block copolymers form diverse nanostructured morphologies depending on block volume fraction and solvophilicity. Stimuli‐responsive motifs have been combined with self‐assembled micelles to afford spatiotemporal, on‐demand encapsulation and payload release. However, the role of modular polymer architecture (i.e., bottlebrushes) in stimuli‐responsive aqueous self‐assembly is not fully understood. The synthesis, aqueous self‐assembly, and photoirradiation of photolabile, amphiphilic bottlebrush block copolymers is presented herein. Specifically, the efficient photoscission of o‐nitrobenzene motifs at the junction of a poly(norbornene o‐nitrobenzene polystyrene)‐block‐poly(norbornene polyethylene glycol) diblock bottlebrush side chain and backbone cleaved away hydrophobic polystyrene side chains and artificially increased the volume fraction of poly(ethylene glycol) (fPEG). In doing so, self‐assembled micelles readily degrade to micelle‐to‐micelle and micelle‐to‐aggregate structures after photoirradiation. Finally, this bottlebrush micelle system is used to demonstrate the efficient encapsulation and stimuli‐responsive release of Nile Red that is monitored by fluorescence spectroscopy and dynamic light scattering. The contribution of this work expands the utility of amphiphilic bottlebrush systems as highly efficient and responsive, hierarchically assembled nanomaterials.

Mechanisms of Block Instability at the Toe of a Slowly Deforming Rock Slope

Steep alpine rock slopes undergoing deformation may give rise to concurrent landslide hazards of different type and magnitude. The underlying mechanisms of instability are often challenging to investigate due to their inherent complexity; furthermore, they can occur on poorly accessible terrain, preventing the collection of data by means of traditional field techniques or even inhibiting awareness of hazards. This paper focuses upon one such case, in which a major transportation corridor running along the floor of the Aosta Valley (Western Italian Alps) is affected by significant—and until recently unknown—rockfall hazards promoted by a previously collapsed rockslide still deforming slowly at elevations almost 600 m above the road. In particular, two large discrete blocks (volume > 103 m3) lie precariously at the toe of the slide and could fall downslope at extremely rapid velocity. The design of countermeasures for the stabilization or removal of these blocks would require the assessment of their mechanical interaction with the bedrock and degree of internal fracturing (i.e., possible pervasive damage within the blocks). We perform this task by first exploring potential kinematic styles and damage patterns at failure according to a series of preliminary finite-element models. We then use detailed displacement measurements from remote sensing and in situ monitoring, in conjunction with repeat topographic surveying from a terrestrial laser scanner (TLS) and a drone laser scanner (DLS), to reconstruct the actual kinematics of the blocks. The results substantiate the hypothesis that instability is primarily controlled by transient degradation of friction on a through-going basal rupture surface. Development of a large tensile fracture in one of the two blocks is inferred to be conditioned by increased non-planarity of the slipping joint in comparison with the other block. We highlight that optimized integration of cutting-edge rock slope investigation tools can help address otherwise unresolved key aspects of complex instabilities in steep mountainous areas.

Effect of MgO and Al2O3 on High-temperature Stability Performance of High-alumina Cement

High-alumina cement has an important position in refractory materials with its good performance at high temperatures, but its disadvantages such as strength inversion and unstable transformation of hydration products have always limited its development. To clarify the working mechanism of high-alumina cement and improve its high temperature resistance, MgO and Al2O3 were added to the high-alumina cement paste. The optimal design method was used to determine the influence of each factor on the high temperature stability of the cement paste. The mix ratio of raw materials was optimized and the strength change patterns of the specimens under the optimal ratio were verified. From a microstructure perspective, the high temperature evolution of the hardened paste of high-alumina cement was explored using X-ray diffraction, scanning electron microscopy, thermogravimetry, and differential scanning calorimetry. The results show that the introduction of refractory powders, especially Al2O3, can significantly improve the volumetric stability of the cement paste at high temperatures. When the water-cement ratio is 0.20, the admixture of MgO is 5 % or 10 %, and Al2O3 is 20 %, the high temperature volume stability of the cement paste is the best. However, its corresponding mechanical strength is weakened to some extent with an increase in calcinating temperature. Moreover, the structure-property evolution process of cementite under high temperature calcinating conditions was verified by microstructural characterization, especially the influence of the powder on the volume and strength of the cement block at high temperatures. The results of this study can serve as a guide for the development of high-alumina cement and its cementing materials, as well as for the improvement of their properties.

Correlation of axial length with minimal effective volume of peribulbar block

Cataract remains the most common cause of blindness worldwide and surgery is the only option to get rid of a cataract. Good anaesthesia is an essential requirement for performing safe cataract surgery. Peribulbar block using regional anaesthetic is the most common technique of administrating anaesthesia for cataract extraction. The study aimed to know the relationship between the axial length and the minimal effective volume of the peribulbar block. The study was done in a hospital based in the rural area of Panipat. It was a cross-sectional study done on patients who underwent cataract surgery and met the inclusion and exclusion criteria of the study. The patients were divided into two groups based on axial length and were given peribulbar block using 2% lignocaine with 1500 IU of hyaluronidase of 6 ml and 8 ml. The subsequent doses of the block were given in those in which adequate response was not present. The study includes 100 patients divided into two groups. The patients in group 1 had axial lengths between 21-23.99 mm and the second group included patients with axial lengths of 24-26.99 mm. In group 1 the volume of peribulbar block given was higher than that in group 2. The maximum number of patients in group 1 (34) were given an 8 ml block and those in group 2 were given a 6 ml of block. The study had a p-value of 0.02. In our study, we found that axial length has a negative correlation with the volume of the peribulbar block. It was also seen that there was an increase in IOP with more amount of local anaesthetic used in the peribulbar block.

PENGGUNAAN MODEL CONTEXTUAL TEACHING AND LEARNING UNTUK MENINGKATKAN KEMAMPUAN PEMECAHAN MASALAH MATEMATIS SISWA SEKOLAH DASAR

This study was conducted with the aim of determining the effect of using the Contextual Teaching and Learning model in improving students' mathematical problem solving abilities. This research was carried out at SD N 1 Ujungpandan Welahan Jepara with the research subjects of 21 students on the volume of cubes and blocks for the 2022/2023 academic year. The research method used is classroom action research, which is carried out over two cycles, each cycle consisting of three meetings. This study also used data collection techniques of interviews, observations, tests, and documentation. Data analysis of this study used quantitative and qualitative. The results showed that in cycle I, students' mathematical problem-solving ability increased from precycle 38% to 71%. In cycle II, students' mathematical problem-solving ability also increased to 100%. This is because the teacher has related the material according to everyday life so that students are easier to solve the problem of cube and block volume. Thus, the use of the CTL model can improve the mathematical problem solving ability of grade V students of SD N 1 Ujungpandan.

Influence of uncertainties: A focus on block volume and shape assessment for rockfall analysis

Influence of uncertainties: A focus on block volume and shape assessment for rockfall analysis