Open Face Research Articles

A Supramolecular‐Nanocage‐Based Framework Stabilized by π‐π Stacking Interactions with Enhanced Photocatalysis

Abstractπ frameworks, defined as a type of porous supramolecular materials weaved from conjugated molecular units by π‐π stacking interactions, provide a new direction in photocatalysis. However, such examples are rarely reported. Herein, we report a supramolecular‐nanocage‐based π framework constructed from a photoactive Cu(I) complex unit. Structurally, 24 Cu(I) complex units stack together through π‐π stacking interactions, forming a truncated octahedral nanocage with sodalite topology. The inner diameter of the nanocage is 2.8 nm. By sharing four open faces, each nanocage connects with four equivalent ones, forming a 3D porous π framework (π‐2). π‐2 shows good thermal and chemical stability, which can adsorb CO2, iodine, and methyl orange molecules. More importantly, π‐2 can serve as a photocatalyst for hydrogen evolution reaction. With ultrafine Pt subnanometer particles (0.9±0.1 nm) incorporated into the nanocages as a co‐catalyst, the hydrogen evolution rate reaches a record‐high value of 524012 μmol/gPt/h in the absence of any additional photosensitizers. The high photocatalytic activity can be ascribed to the ultrafine size of the Pt particles, as well as the fast electron transfer from π‐2 to the highly active Pt upon illumination. π‐2 represents the unique stable supramolecular‐cage‐based π framework with excellent photocatalytic activity.

A Supramolecular-Nanocage-Based Framework Stabilized by π-π Stacking Interactions with Enhanced Photocatalysis.

π frameworks, defined as a type of porous supramolecular materials weaved from conjugated molecular units by π-π stacking interactions, provide a new direction in photocatalysis. However, such examples are rarely reported. Herein, we report a supramolecular-nanocage-based π framework constructed from a photoactive Cu(I) complex unit. Structurally, 24 Cu(I) complex units stack together through π-π stacking interactions, forming a truncated octahedral nanocage with sodalite topology. The inner diameter of the nanocage is 2.8 nm. By sharing four open faces, each nanocage connects with four equivalent ones, forming a 3D porous π framework (π-2). π-2 shows good thermal and chemical stability, which can adsorb CO2, iodine, and methyl orange molecules. More importantly, π-2 can serve as a photocatalyst for hydrogen evolution reaction. With ultrafine Pt subnanometer particles (0.9±0.1 nm) incorporated into the nanocages as a co-catalyst, the hydrogen evolution rate reaches a record-high value of 524012 μmol/gPt/h in the absence of any additional photosensitizers. The high photocatalytic activity can be ascribed to the ultrafine size of the Pt particles, as well as the fast electron transfer from π-2 to the highly active Pt upon illumination. π-2 represents the unique stable supramolecular-cage-based π framework with excellent photocatalytic activity.

A New Family of Solids: The Infinite Kepler-Poinsot Polyhedra

The so-called Platonic solids have fascinated mathematicians and artists for over 2000 years. It is astonishing that there are only five cases of regular polyhedra, that is, of polyhedra in which regular polygons form the same spatial angles between them in each vertex. In 1619, Kepler added the small and great stellated dodecahedron to this list, but he allowed intersecting faces. Poinsot did so too, in 1809, and discovered the great dodecahedron and great icosahedron. In 20th century, Coxeter and Petrie added three more regular polyhedra, using infinitely repeating elements, based on the truncated tetrahedron, the cube and the truncated octahedron. The principle of intersecting faces, typical for the Kepler-Poinsot solids, can be combined with the Coxeter-Petrie generalization to the infinite case. Thus, a new regular polyhedron was discovered, based on the cubohemioctahedron but without its square faces. Placed side by side and on top of each other, identical regular hexagons meet in each vertex, always with the same spatial angle. There are 8 of them in each vertex, and so it is not a compound of twice two polyhedra with 4 hexagons in each vertex. The dual of this {6, 8} polyhedron of infinite Kepler-Poinsot type is indeed a {8, 6} polyhedron of infinite Kepler-Poinsot type, if two overlapping squares are considered as one 8/4 octagonal star. Kepler-Poinsot solids are difficult to interpret, with their intersecting faces, and this infinite case is even more difficult to grasp. The present paper tries to solve this using open faces so that one can see through the solids.

Pnictogen Bonding at the Core of a Carbene-Stiborane-Gold Complex: Impact on Structure and Reactivity.

Our interest in the design of ambiphilic ligands and their coordination to gold has led us to synthesize an indazol-3-ylidene gold chloride complex functionalized at the 4-position of the indazole backbone by a stibine functionality. The antimony center of this new complex cleanly reacts with o-chloranil to afford the corresponding stiborane derivative. Structural analysis indicates that the stiborane coordination environment is best described as a distorted square pyramid whose open face is oriented toward the gold center, allowing for the formation of a long donor-acceptor, or pnictogen, Au → Sb bonding interaction. The presence of this interaction, which has been probed computationally, is also manifested in the enhanced catalytic activity of this complex in the cyclization of N-propargyl-4-fluorobenzamide.

Visual-Preserving Mesh Repair.

Mesh repair is a long-standing challenge in computer graphics and related fields. Converting defective meshes into watertight manifold meshes can greatly benefit downstream applications such as geometric processing, simulation, fabrication, learning, and synthesis. In this work, by assuming the model is visually correct, we first introduce three visual measures for visibility, orientation, and openness, based on ray-tracing. We then present a novel mesh repair framework incorporating visual measures with several critical steps, i.e., open surface closing, face reorientation, and global optimization, to effectively repair meshes with defects (e.g., gaps, holes, self-intersections, degenerate elements, and inconsistent orientations) and preserve visual appearances. Our method reduces unnecessary mesh complexity without compromising geometric accuracy or visual quality while preserving input attributes such as UV coordinates for rendering. We evaluate our approach on hundreds of models randomly selected from ShapeNet and Thingi10K, demonstrating its effectiveness and robustness compared to existing approaches.

Hydroxyl on Stepped Copper and its Interaction with Water.

We describe the hydroxyl and mixed hydroxyl-water structures formed on a stepped copper surface following the reaction of adsorbed O with water at a low temperature and compare them to the structures found previously on plane copper surfaces. Thermal desorption profiles, STM, and low-energy electron diffraction show that water reacts with O at temperatures below 130 K on Cu(511). Two well-defined phases appear as the OH/H2O layer is heated to desorb excess water, a 1OH:1H2O phase and a pure OH phase. The 1OH:1H2O structure consists of 1D chains binding across two adjacent copper steps, with a double period along the step. Electronic structure calculations show that the structure has a zigzag chain of water along the terrace, stabilized by hydrogen bonds to OH groups adsorbed in the step bridge sites. This structure binds OH in its favored site and is similar to the structure observed on other open faces of Cu and Ni, suggesting that this structural arrangement may be common on other surfaces that have steps or rows of close packed metal atoms. The hydroxyl/water chains decompose at 210 K to leave OH adsorbed in the Cu step bridge site, with some forming H-bonded trimers that bridge between two Cu steps. Heating the surface causes hydroxyl to disproportionate near 300 K, desorbing water to leave chemisorbed O.

Assessment of BFX cup version in a three-dimensional model simulating the ventrodorsal radiographic view.

To measure truncated face and open face versions of the biological fixation (BFX) cup in a three-dimensional (3D) model simulating the ventrodorsal radiographic projection with different cup and pelvis positions. Computer simulation. Simulated ventrodorsal views were generated in silico using 3D models of a BFX cup and a medium-sized canine pelvis. Truncated face and open face versions of the BFX cup were defined and measured with various angles of cup version, cup inclination, and pelvic extension. Truncated face version was different from and underestimated open face version by 12° to 22° (p < .001). Open face version varied with inclination while truncated face version was unaffected by inclination. Open face version was dependent on the degree of pelvic extension while truncated face version was unaffected. Open face version differed from truncated face version. Changes in open face version were not consistently matched by a change in truncated face version. The open face of the cup may be excessively retroverted without this being reflected by truncated face retroversion as seen on a ventrodorsal radiographic view. However, in this study, BFX cups placed with truncated face version and inclination in the normal range and an ALO of 45° yielded predictable open face version.

The Impact of Scenario Planning in Managing Complexity Strategy: The Mediating Role of Strategic Flexibility: An Applied Study of the Opinions of a Sample of Managers of the General Company for Construction Contracting in Baghdad

The aim of this study was to examine the impact of scenario planning on managing complexity strategy and investigate whether strategic flexibility acts as a mediator between scenario planning and complexity strategy. The study was conducted on a sample of 75 employees from the General Company for Construction Contracting in Baghdad out of a study population of 400 employees. The data was collected through a questionnaire that was distributed to various department managers in the company. The study aimed to test several hypotheses and sub-hypotheses related to the relationship between the study variables. The study results indicate that there is a positive relationship between scenario planning and complexity strategy, although it is only partial. The study also found that strategic flexibility partially mediates the relationship between scenario planning and complexity strategy. Therefore, scenario planning can enhance complexity strategy, but strategic flexibility plays a crucial role in mediating this relationship. The study recommends that cognitive skills of the scenario drafting team should be developed, particularly in the areas of induction and deduction, to facilitate the identification of pre-determined factors and the formulation of flexible assumptions for scenarios. Additionally, the study suggests expanding the scope of competitive flexibility and productivity in the face of intense betting, globalization and openness, as well as achieving a competitive position aligned with the company's objectives based on the structure of complexity theory.

Variation in soil organic carbon with structural composition of mangrove species in the Sundarbans

The world's biggest continual mangrove swampy land is the Sundarbans Mangrove Forest, which is crucial to both the terrestrial and marine carbon cycles. While numerous studies have focused on organic carbon variations within this ecosystem, few have explored the interaction between carbon stocks and the structural composition of mangrove species. This study sought to investigate the connection between soil organic carbon accumulation and functional attributes of vegetation (DBH, basal area). This study was carried out on four vegetative and two non-vegetative plots in three different sites within the oligohaline zone. Based on species Iv, the Karamjol area was prevalent by Heritiera fomes (Iv =139.3). In contrast, the Ghagramari area was predominated by Avicennia officinalis (IV =105.1). Accumulation of TBC, Avicennia officinalis presented the highest, despite having a smaller number of individuals within the study area. 1 m soil core was pulled out from each subplot of each main plot by using a one-meter-long open face peat auger. The forest areas exhibited maximum soil organic carbon accumulation, which was significantly (p < 0.01) higher than non-vegetative areas. Moreover, the mean soil C/N ratios in the Karamjol area (13.4±0.2) and Ghagramari area (13.2± 0.2) were significantly (p < 0.01) greater than those in the non-vegetative area (12.3±0.1). These findings suggest that regardless of the dominant species, species richness, or size (tall or dwarf) of the mangroves, a particular quantity of organic carbon is captured within the mangrove soil. Thus, when making future decisions, it is crucial to repute the role of the Sundarbans mangrove in the accumulation of organic and biomass carbon, which can directly affect mitigating global warming.

Enhancing security and privacy in smart agriculture: A novel homomorphic signcryption system

Technology driven Smart Agriculture is transforming modern day farming practices through digital tools and real-time data analysis. It monitors plant health in both soil and soilless cultivation, promoting environmentally responsible practices by utilizing integrated sensors and precision methods. Despite the significant potential benefits, challenges persist in ensuring data security in the smart agriculture frameworks. The existing research has explored various mechanisms to cater these issues, yet these solutions susceptible to known attacks i.e., Confidentiality, Authentication, Privacy preservation. Notably, the available schemes in open literature face performance deficiencies due to an overreliance on Rivest-Shamir-Adleman (RSA), bilinear pairing, and elliptic curve (EC). To comprehensively address these challenges, this study presents a novel approach via employing homomorphic Signcryption based on Hyper-Elliptic Curves (HEC). Our HEC based Signcryption technique enhances security with lower computational cost and communication overhead as compared to the existing techniques. Furthermore, our solution provides the best performance in terms of efficiency, addressing the privacy preservation issues with conformance to the (Confidentiality, Integrity, and Availability) CIA triad. For proof of concept and correctness, we have validated the results in Scyther tool, with the assurance that proposed scheme is correct, verified, and resistant against known set of attacks. The proposed scheme achieves a remarkable reduction in both computational and communication costs around 95.08 % and 89.28 % respectively, enhancing practicality and suitability for real-world implementation. Thus, making it a suitable candidate for employing in smart agriculture environments, encompassing both soil and soilless cultivation scenarios. This research contributes a robust, secure, cost effective, and efficient solution to the challenges posed by the evolving landscape of agriculture, paving the way for enhanced data protection and system resilience in smart agriculture systems.

2390: Evaluation and implementation of open face masks with surface-guided radiotherapy (SGRT)

2390: Evaluation and implementation of open face masks with surface-guided radiotherapy (SGRT)

Tools for studying of facial identification and authentication

One of the most common and popular among biometric techniques is biometry of face. Currently, a large number of information systems have been created using these techniques. Thus, there is a problem of studying the methods of machine face recognition during the training of relevant specialists. The aim of the work is to develop a software tools for studying the mechanism of biometric face authentication. Face is static biometry methodic. For implementation in the developed tools the method of comparison on key points was chosen. The main stages of comparing faces are: finding a face in a photo, formation of key points, normalization, formation of segments, formation of relations, comparison of ratios. A high-level cross-platform programming language C++ with the use of additional libraries was chosen to develop the software of the tools. An open face database was used to work with the tools. The tools have a demonstration nature. During its use, you can explore and study all the components of the process of biometric identifi-cation and authentication of the user by face: demonstration of the process of finding of key points on the face, forming of distances between points, calculating of their ratios and their comparison; comparison of etalon and candidate photos during the procedure of identification and authentication and response. Examples of the main processing stages of the complex and the corresponding screen forms (windows) are given. The com-position of the tools and software are developed in the work, the main examples and stages of its work are given. It is shown that the tools can be used in the educational process, for example in laboratory or practical classes.

Effect of laser treatment on strength of moisture-degraded epoxy adhesive joints and microscopic observation of treated surface

ABSTRACT We examined the effect of laser processing surface treatment on the mechanical strength of adhesion. In addition to laser processing, double cantilever beam (DCB) and lap joint (LJ) specimens were prepared using an epoxy adhesive on aluminum plates that underwent acid etching, sandblasting, and acetone wiping. The open face method was employed to accelerate moisture degradation, and the tensile-shear strength and energy release rate of the specimens were measured. Laser processing resulted in remarkably high values of the measured energy release rate, even when the adhesive deteriorated. To examine the reason for the high strength, we performed a detailed fracture surface analysis and electron microscopic observation of the adhesive interface. When the interface of the fractured surface was observed, the laser treated surface was densely formed with fine filamentous protrusions that held the adhesive well. These filaments exhibited high oxidation resistance and achieved strong adhesion even when the adhesive and adherend deteriorated because of moisture. The laser treated adherend surface exhibited two strong anchoring effects owing to a significant increase in the surface area and the microfilamentous structure on the surface. However, the type of surface treatment did not have a significant effect on the LJ adhesion strength.

The influence of helmet certification in motorcycle helmets protective performance

The convenience of online shopping has increased access to a vast array of helmet options and deals for motorcyclists. However, the e-commerce enables an influx of unverified and potentially hazardous helmets lacking the rigorous quality control into the market, hence, placing unaware bargain seekers at risk. The non-certified variants questions in terms of impact protection abilities because they visually look similar to certified helmets. This study compared certified full face and open face helmets against their non-certified counterparts by analysing injury predictor metrics. Using a test rig simulating 5.58 ± 0.29 m/s impacts, an anthropomorphic test device wearing both helmet types and certification statuses measured peak resultant linear and angular accelerations, head injury criterion alongside brain injury criteria scores. The data revealed comparable side and rear impact performance between non-certified and certified helmets. However, frontal impacts exposed deficiencies without certification. The non-certified full face helmets registered over twice the peak linear acceleration of certified while open face types still exceeded certified by 40% in frontal impacts. Additionally, non-certified full face helmets indicated up to 100% predicted concussion risks in side and frontal crashes based on the angular accelerations. The poorer frontal impact and elevated injury odds demonstrate certification's key safety advantages that certification should not be ignored while it still providing more protection than no helmet. However, individual needs to carefully select helmets due to performance differences of helmets. Riders should ultimately prioritize proven protection given the severe consequences of head trauma though non-certified may suffice for some low-risk environments.

Impacts on Urban VOCs and PM2.5 during a Wildfire Episode

This study focuses on the impact of wildfire smoke emissions on regional, urban air quality during a wildfire event. We measured volatile organic compounds (VOCs) and fine particulate matter (PM2.5) in the San Francisco Bay Area to assess air quality during a wildfire event and compared them to those in a later non-wildfire period. VOCs were collected using thermal desorption tubes and quantified using thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS). Elevated concentrations of VOCs such as 1,3,5-trimethylbenzene (0.33 ± 0.01 µg/m3), benzene (1.03 ± 0.02 µg/m3), toluene (2.15 ± 0.04 µg/m3), ethylbenzene (0.60 ± 0.02 µg/m3), and m, p-xylene (0.77 ± 0.07 µg/m3) were observed in the wildfire event. Compared with that in the non-wildfire season, the toluene concentration during the wildfire period was more than three times the non-wildfire concentration. Similarly, the benzene concentration during the wildfire was almost four times higher, and that of p, m-xylene was three times higher. The higher wildfire levels were statistically significant for sec-butylbenzene, 1,2,4-trimethylbenzene, n-propylbenzene, o-xylene, styrene, 1,3,5-trimethylbenzene, benzene, toluene, ethylbenzene, and p,m-xylene (p &lt; 0.00001). These higher VOC levels compared with those for the non-fire period may potentially pose a public health concern. Open face passive sampler (OFPS)-collected PM was analyzed using scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and revealed organic carbon tar balls. The highest daily average beta-attenuation-monitored PM2.5 during the fire period was 200 µg/m3 and the highest hourly average was 270 µg/m3. Monitoring gas phase species in addition to PM concentrations is useful during wildfire season to inform public health guidance.

196 Evaluation and implementation of open face masks with surface-guided radiotherapy (SGRT)

196 Evaluation and implementation of open face masks with surface-guided radiotherapy (SGRT)

Challenges Facing ODL Students when Conducting Research in Tanzania: A Case of Institute of Adult Education Regional Centres

This study examined challenges that Open and Distance Learning (ODL) students face when conducting research in the Institute of Adult Education Regional Centres, Tanzania. A quantitative research approach with descriptive cross-sectional survey design were used in this study. The sample of this study involved ODL diploma students who were in their final stage of the research project in 2018. Simple random sampling technique was employed to select a sample of 80 students. Data were collected through questionnaires. A validated instrument with a test–retest reliability coefficient of 0.84 was used to elicit responses from respondents. The instrument was validated to ensure its accuracy, relevance, and effectiveness in measuring what it intended to measure. Data were analysed using descriptive statistics using SPSS version 20.0software. The study found out that challenges faced by students when conducting research were of three categories: student-related challenges, supervisor-related challenges and institutional-related challenges. This study recommends that there is a need for regular workshops for research supervision to supervisors, motivating supervisors to attend and present papers at local and international conferences. Students should start planning in early enough on how to carry out the research studies. Meanwhile, adopting a COSTA model of supervision should be made as it provides a structured framework for effective supervision, facilitation, clearer communication, goal alignment and strategic planning. Keywords: Challenges, students, ODL, research, Tanzania

Performance study of a thermochemical energy storage reactor embedded with a microchannel tube heat exchanger for water heating

Thermochemical energy storage (TCES) provides a promising solution to addressing the mismatch between solar thermal production and heating demands in buildings. However, existing air-based open TCES systems face practical challenges in integrating with central water heating systems and controlling the supply temperature. To overcome these limitations, a novel water-based TCES-HEX-HRU system is proposed in this study, which integrates a water-to-air microchannel tube heat exchanger (HEX) and an air-to-air heat recovery unit (HRU). A comprehensive evaluation of the TCES-HEX-HRU system is conducted numerically using a COMSOL model, including a comparative assessment for different TCES system configurations. The results demonstrate that the TCES-HEX-HRU system achieves an overall thermal efficiency of 82.35 %, marking a substantial 69 percentage points improvement over the TCES-HEX system. Although slightly lower than the typical air-based TCES system without HEX and HRU by 15.44 percentage points, the TCES-HEX-HRU system can be a practically promising and viable choice for applications in central heating systems. Numerical investigations indicate that the thermal performance of the system is influenced by the inlet conditions of airflow and waterflow. Moreover, increasing the number of water channels in the HEX of the TCES-HEX-HRU system enhances heat transfer but reduces the amount of heat released by TCES composite materials, resulting in a maximum overall thermal efficiency of 92.09 % with 35 channels and a peak outlet water temperature of 33.67 °C at with 30 channels. However, further increases in the number of channels lead to a decline in overall thermal efficiency and outlet water temperature. Changes in the width of water channels in the HEX have a minor impact on the highest outlet water temperature and overall thermal efficiency, while affecting the volume of the TCES composite materials.

Оценка степени воздействия виброакустических факторов производственной среды на работников горнодобывающей промышленности Арктической зоны

Assessment of occupational health risks for workers with basic mining occupations including those exposed to elevated levels of vibroacoustic factors remains a topical issue. Given that, the aim of this study was to assess degree of exposure to occupational vibroacoustic factors and its effects on mining industry workers in the Arctic zone using occupational risk as a basic criterion. Prior risk assessment relied on results of hygienic assessment of vibroacoustic factors according to data derived by the Special Assessment of Working Conditions (SAWC) and verified by instrumental research. Posterior risk quantification was performed using data on occupational incidence among workers over the last 10 years considering their numbers. Unacceptable prior occupational risks caused by exposure to noise were detected for all analyzed occupations. According to instrumental research, risks levels higher than those identified by SAWC were detected for open face miners and cargo handling machine operators. According to SAWC data, unacceptable prior occupational risks caused by exposure to vibration were identified only for cargo handling machine operators; additional instrumental research identified such levels of occupational risks for them as well but also for blast hole drillers. Occupational risk quantification established that unacceptable (above 1•10-3) levels of occupational risk caused by vibration disease (VD) and sensorineural hearing loss (SHL) were detected in all analyzed occupational groups. The highest risk levels caused by exposure to vibration were identified for such an occupational group as ‘cargo handling machine operators’ and ranked as ‘average’ (1.37•10-2). The highest risk levels caused by exposure to noise were identified for timbermen and were also ranked as ‘average’ (1.32•10-2). Results obtained by quantification of occupational health risks for mining industry workers in the Arctic zone refine results of prior assessment can be applied in planning activities aimed at mitigating health risks for workers caused by exposure to vibroacoustic factors.

Assessing degree of exposure to vibroacoustic occupational factors for mining industry workers in Аrctic zone

Assessment of occupational health risks for workers with basic mining occupations including those exposed to elevated levels of vibroacoustic factors remains a topical issue. Given that, the aim of this study was to assess degree of exposure to occupational vibroacoustic factors and its effects on mining industry workers in the Arctic zone using occupational risk as a basic criterion. Prior risk assessment relied on results of hygienic assessment of vibroacoustic factors according to data derived by the Special Assessment of Working Conditions (SAWC) and verified by instrumental research. Posterior risk quantification was performed using data on occupational incidence among workers over the last 10 years considering their numbers. Unacceptable prior occupational risks caused by exposure to noise were detected for all analyzed occupations. According to instrumental research, risks levels higher than those identified by SAWC were detected for open face miners and cargo handling machine operators. According to SAWC data, unacceptable prior occupational risks caused by exposure to vibration were identified only for cargo handling machine operators; additional instrumental research identified such levels of occupational risks for them as well but also for blast hole drillers. Occupational risk quantification established that unacceptable (above 1•10-3) levels of occupational risk caused by vibration disease (VD) and sensorineural hearing loss (SHL) were detected in all analyzed occupational groups. The highest risk levels caused by exposure to vibration were identified for such an occupational group as ‘cargo handling machine operators’ and ranked as ‘average’ (1.37•10-2). The highest risk levels caused by exposure to noise were identified for timbermen and were also ranked as ‘average’ (1.32•10-2). Results obtained by quantification of occupational health risks for mining industry workers in the Arctic zone refine results of prior assessment can be applied in planning activities aimed at mitigating health risks for workers caused by exposure to vibroacoustic factors.