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Experimental Study of Persons with Disability, Wheelchairs, and Car Interaction
Driving a car independently significantly enhances the quality of life, particularly for individuals with mobility disabilities. Wheelchair users face several challenges when loading and unloading their wheelchairs into and from vehicles, hindering their personal transportation independently. The influence of wheelchair design on the wheelchair and car compatibility for self-loading and unloading hasn't been fully explored in the scientific literature; therefore, this study investigates the impact of various design features found in modern wheelchairs on their suitability for disabled drivers. Four types of wheelchairs were compared in this study; two participants with paraplegia, one male and one female, participated in the tests. Video recordings captured the procedures for getting in and out of the vehicle. Subsequent results analysis involved breaking down these procedures into steps and comparing them. The study demonstrated that times of independent entry into a car and loading of a wheelchair ranged from 48 to 74 seconds, while exiting the vehicle and loading a wheelchair phase took between 56 and 86 seconds. A key takeaway from this research is that dividing the wheelchair frame, the largest and heaviest component, into two parts facilitates loading and unloading processes. However, this may slightly increase the duration of these activities. Detaching the seat aids more individuals with limited upper body strength.
Chair Size Design Based on User Height
General principles derived from anatomical studies of human body sizes should be applied to chair designs. Chairs can be designed for a specific user or a particular group of users. Universal chairs for public spaces should be comfortable for the largest possible group of users and should not be adjustable, such as office chairs. However, the fundamental problem is that the anthropometric data available in the literature either come from many years ago and are out of date or do not provide a complete set of all the dimensional parameters of a sitting human body position. This article proposes a way to design chair dimensions solely based on the height range of the intended chair users. For this purpose, based on literature data, the main structural dimensions of the chair were assigned to the appropriate anthropometric body measurements. Furthermore, calculated average body proportions for the adult population overcome the incompleteness, outdated and burdensome access to anthropometric data and link the main chair design dimensions to one easily accessible anthropometric parameter: human height. This is achieved by seven equations describing the dimensional relations between the chair’s essential design dimensions and human height or even a height range. The result of the study is a method of determining the optimal functional dimensions of a chair for a chosen range of sizes of its future users based only on users’ height range. Limitations of the presented method: the calculated body proportions are correct only for people with a standard body proportion characteristic of adults, i.e., they exclude children and adolescents up to 20 years of age, seniors, and people with a body mass index exceeding 30.
Laboratory Assessment of Manual Wheelchair Propulsion
Self-propelled manual wheelchairs offer several advantages over electric wheelchairs, including promoting physical activity and requiring less maintenance due to their simple design. While theoretical analyses provide valuable insights, laboratory testing remains the most reliable method for evaluating and improving the efficiency of manual wheelchair drives. This article reviews and analyzes the laboratory methods for assessing the efficiency of wheelchair propulsion documented in the scientific literature: (1) A wheelchair dynamometer that replicates real-world driving scenarios, quantifies the wheelchair’s motion characteristics, and evaluates the physical exertion required for propulsion. (2) Simultaneous measurements of body position, motion, and upper limb EMG data to analyze biomechanics. (3) A method for determining the wheelchair’s trajectory based on data from the dynamometer. (4) Measurements of the dynamic center of mass (COM) of the human–wheelchair system to assess stability and efficiency; and (5) data analysis techniques for parameterizing large datasets and determining the COM. The key takeaways include the following: (1) manual wheelchairs offer benefits over electric ones but require customization to suit individual user biomechanics; (2) the necessity of laboratory-based ergometer testing for optimizing propulsion efficiency and safety; (3) the feasibility of replicating real-world driving scenarios in laboratory settings; and (4) the importance of efficient data analysis techniques for interpreting biomechanical studies.
Evacuation chairs: a survey to assess the state of the art and desirable features from the perspective of decision makers
The evacuation chair allows safe and efficient evacuation of people with disabilities or injuriesfrom buildings during emergencies. Therefore, evacuation chairs need to be effective in variousconditions of use. It is crucial to know how to choose the right evacuation chair and how tointegrate it effectively into a specific evacuation system. The article aims to identify expectations forevacuation chairs and to evaluate the level of familiarity with how they work of people organizingan evacuation system. This goal was pursued by surveying 41 people who plan and implementevacuation systems in buildings. The analysis of the research results shows a deficit in practicalknowledge concerning the operation of evacuation chairs; consequently, it justifies and suggeststhe need for further action in this area. The respondents chose the answer that seemed to be assafe as possible without having to go into details. They were unable to effectively define the rightexpectations for evacuation chairs. The training of chair use should include brake functioning,the role of the belt securing the head and a leg belt. Users have partially conflicting demands forthe chair, which shows a lack of established criteria, probably due to the lack of practical experiencein the use of emergency chairs. The decision-making model and the factors that affect purchaseshould be examined to determine their needs more precisely. The specific needs of all three groupsof users should be established, and potential antinomies between features should be recognizedand overcome. The study also suggests that future research should focus on the decision-makingprocess, ergonomic quality and measuring the impact of training on the actual effectiveness ofthe evacuation system. In addition, the study also highlights the need for in-depth research andconsideration of user needs in the design process.
Mycelium-Based Composites in Art, Architecture, and Interior Design: A Review
Mycelium-based composites (MBCs) have attracted growing attention due to their role in the development of eco-design methods. We concurrently analysed scientific publications, patent documents, and results of our own feasibility studies to identify the current design issues and technologies used. A literature inquiry in scientific and patent databases (WoS, Scopus, The Lens, Google Patents) pointed to 92 scientific publications and 212 patent documents. As a part of our own technological experiments, we have created several prototype products used in architectural interior design. Following the synthesis, these sources of knowledge can be concluded: 1. MBCs are inexpensive in production, ecological, and offer a high artistic value. Their weaknesses are insufficient load capacity, unfavourable water affinity, and unknown reliability. 2. The scientific literature shows that the material parameters of MBCs can be adjusted to certain needs, but there are almost infinite combinations: properties of the input biomaterials, characteristics of the fungi species, and possible parameters during the growth and subsequent processing of the MBCs. 3. The patent documents show the need for development: an effective method to increase the density and the search for technologies to obtain a more homogeneous internal structure of the composite material. 4. Our own experiments with the production of various everyday objects indicate that some disadvantages of MBCs can be considered advantages. Such an unexpected advantage is the interesting surface texture resulting from the natural inhomogeneity of the internal structure of MBCs, which can be controlled to some extent.
Podstawy CAD : Ćwiczenia w Autodesk Inventor
Niniejsza książka jest przewodnikiem do ćwiczeń z przedmiotu „Podstawy CAD”, prowadzonego na Wydziale Leśnym i Technologii Drewna Uniwersytetu Przyrodniczego w Poznaniu w ramach studiów pierwszego stopnia na kierunku technologia drewna. Przedstawiono w niej informacje dotyczące efektywnego korzystania z oprogramowania Autodesk Inventor Professional przez osoby rozpoczynające projektowanie za pomocą oprogramowania CAD. Książka zawiera krótkie wprowadzenie do tego programu, scenariusze dwunastu ćwiczeń, wskazówki dotyczące zasad tworzenia dokumentacji wykonawczej (rysunków technicznych) oraz zadania projektowe do samodzielnego rozwiązania. Zaproponowane scenariusze ćwiczeń obejmują projektowanie części i zespołów, opracowywanie typoszeregów wyrobów, tworzenie dokumentacji wykonawczej (w tym rysunków wykonawczych i złożeniowych) oraz wykonywanie instrukcji montażu. Uzupełnieniem są informacje dotyczące inżynierskich obliczeń wytrzymałościowych wykonywanych przy użyciu Inventora oraz automatyzacji działań podczas przygotowywania dokumentacji CAD. W publikacji skoncentrowano się na praktycznych aspektach korzystania z wybranego oprogramowania CAD.
Differences in employee motivation in wood-processing enterprises in selected countries of Central Europe
Quantifying the finest particles in dust fractions created during the sanding of untreated and thermally modified beech wood
This article deals with the fractionation of wood dust by sieve after sanding. Dust from untreated beechwood was compared to dust from thermally modified beechwood (at 200 °C for 3 h). The authors hypothesized that the thermal modification changes the particle size distributions of the dust sieve fractions and that all the dust sieve fractions contain the finest particles, which are suspendable in the air and are potentially respirable. To obtain dust for testing, both wood materials were sanded with P120 paper at a belt speed of 14.5 m/s and a pressure of 0.65 N/cm2. A set of sieves with aperture sizes of 25, 80, and 250 µm were used to separate the dust into sieve fractions with grain sizes less than 25 µm, 25 to 80 µm, 80 to 250 µm, and greater than 250 µm. The content of the finest particles in the fractions was measured via a laser particle sizer. Both dusts had similar particle size distributions. In addition, each investigated fraction of both dusts contained the finest particles, i.e., less than 10 µm. It follows that the laser analysis method may be necessary to correctly assess the occupational risk at a sanding.
Indentation Hardness and Elastic Recovery of Some Hardwood Species
The purpose of the study was to measure the Brinell hardness (HB) of six wood species and evaluate the ability to recover the depth of the imprint (self-re-deformation). Straight-grain clear samples of ash, beech, alder, birch, iroko, and linden wood were prepared. Measurements were made in the three main reference timber cross-sections: radial (R), tangential (T), and axial/longitudinal (L) and with two measuring loads of 30 kG and 100 kG (294.2 N and 980.7 N). The tested wood species could be classified into hard (ash, beech), medium-hard (alder, birch, iroko), and soft (linden) wood species. The HBs of each tested wood species differed in the cross-sections, i.e., side hardness (R, T) and end hardness (L). Higher HB values were obtained at 100 kG load in all species and all three cross-sections. The lowest influence of the measurement force value on the HB value was revealed for the soft wood species (linden: 107–118%). This influence was visible for the other five medium-hard and hard wood species, ranging from 125% to 176%. The percentage of temporary imprint in total imprint depth (x/H) varied from 12 to 33% (linden 12–18%—the lowest self-re-deformation ability; beech 25–33%—the highest self-re-deformation ability). The results of this study underline that the higher the density of the wood, the higher the Brinell hardness, and, simultaneously, the greater the measurement force used, the higher the Brinell hardness measured. The ability of self-re-deformation in wood’s R and T cross-sections depends on the wood density and the measuring force used. In contrast, this ability only depends on the wood density in the L cross-section. Those observations imply that the compaction of the cell structure during side compression is mainly non-destructive, while the longitudinal deformation of the cell structure (the buckling of cell walls and fracture of ends of the cells) is to a great degree destructive and irreversible. These results can be used in the construction and furniture sectors, especially when designing products and planning the woodworking of highly loaded wood floors and furniture elements.
Analyzing Joinery for Furniture Designed for Disassembly
End-users can design personalized furnishing products using remote web-based CAD systems. However, if these designs fail to incorporate design for disassembly (DfD) principles, the furniture’s subsequent repair, reconfiguration, recycling, and disposal can be significantly hindered. To address this drawback, this study supports DfD, a strategy that enables the creation of easily repairable, reusable, and recyclable furniture to reduce waste and environmental impact. Consequently, this review aims to classify and evaluate available furniture joinery systems for their suitability within DfD frameworks, ultimately promoting their implementation within CAD environments. To this end, various solutions were evaluated, including traditional joints, dowel/biscuit, hammered, directly screwed, snap-on, expandable, and cam/bolt fasteners. Based on a literature review and practical observations, the analyzed joinery systems were categorized into non-disassemblable, conditionally disassemblable, and fully disassemblable categories. Only the fully disassemblable solutions effectively align with DfD principles. The study postulates a preference for expandable and cam/bolt fasteners in furniture designs, noting that although snap-on fasteners can potentially support DfD, this outcome is not always ensured. To guarantee that the designed furniture adheres to the DfD principles, the following eight furniture design guidelines were formulated: develop web-accessible disassembly instructions, prioritize access to fast-wearing components, prioritize modularity, standardize parts in modules, label components, enable independent component removal, use materials that withstand repeated disassembly, and employ fully disassemblable joints.
Dimensional Solution of Wooden Chairs for the Adult Bariatric Population of Slovakia: Observational Study
Designing Innovative Assistive Technology Devices for Tourism
Active tourism improves human health and well-being regardless of age or disabilities. The paper analyses and describes current issues concerning the tourism of people with disabilities. The starting point is the currently insufficient availability of tourist offers for individuals with considerable motor dysfunctions. One of the causes for these limitations stems from deficiencies in transport means for people with disabilities. It was found that for a disabled passenger using public transport, it is crucial to consider its accessibility in the context of the entire transport system. Another cause is the limited popularity of innovative, atypical assistive equipment for people with disabilities. Those insights point out that novel assistive technologies need to be developed, as it is necessary to more effectively support the activity of people with disabilities in all areas of life, including tourism, as this enhances their social rehabilitation. This paper indicates the needs and describes and analyses examples of own original, innovative devices supporting the areas mentioned above of activity for people with disabilities. These analyses resulted in developing an algorithm to design innovative equipment, considerably expanding the tourism potential of people with motor disabilities. This design process focuses on the needs of people with disabilities and facilitates the development of novel classes of assistive technologies, thus promoting new areas of activity for all.
Effect of Low-Thermal Treatment on the Particle Size Distribution in Wood Dust after Milling
The thermal treatment of wood can improve the appearance of the wood product’s surface, its dimensional stability, and resistance to fungal attacks. However, the heat treatment changes the technological properties of wood, making it a new engineering material. This work investigates the effect of the low-thermal treatment of birch wood (Betula pendula Roth.), European beech wood (Fagus sylvatica L.), and alder wood (Alnus glutinosa L.) on the fine dust particles creation during woodworking. The samples of thermally treated wood with temperatures commonly used for the change of wood colour (105, 125, and 135 °C) were compared with reference samples made of natural wood. All 12 variants of the tested woods were milled using the 5-axis CNC machining center (20 mm diamond cutter, rotational speed 18,000 rev·min−1, the depth of cut 3 mm, feed rates of 2, 4 and 6 m∙min−1). A sieving analysis method allowed measuring the dust particle size distributions in all dust samples. The experiment’s result analysis points out that wood type, thermal treatment, and feed rate meaningfully affect the size distribution of dust particles. Compared to birch wood and beech wood, the milling of alder wood samples created a much higher content of the finest dust particles, with particle sizes smaller than 0.032 mm. Increased temperatures in thermal treatment increase the share of fine dust particles with sizes smaller than 0.125 mm, compared to wood in its natural state. Milling with a lower feed rate (2 m·min−1) creates finer dust than processing with higher feed rates (4 and 6 m·min−1). Generally, the milling of alder in a natural or thermally treated state is a source of fine dust particles, particularly at low feed speed-rate milling, compared to birch and beech wood. In general, these results indicate that the low temperature thermal treatment parameters attribute new technological properties to all thermally modified types of wood tested.
Economic Efficiency of Pine Wood Processing in Furniture Production
The wood industry faces challenges due to rising prices and limited wood availability, putting pressure on material efficiency in wood processing. This justifies the analysis of the relationship between efficiency and economy in pine wood processing. The study aimed to measure the impact of variations in the thickness of logs, changes in the technology of their further processing, and changes in prices of raw materials and products on the material efficiency in the context of large-scale production of furniture elements made of pinewood. The raw material input consisted of three categories of log sizes, from which the specialized purpose lumber was produced. The lumber was then processed into semi-finished furniture elements with three technologies: without detecting natural wood defects, with human detection, and with automatic detection. The study was conducted in Poland from 2020 to 2022. The material efficiencies in every stage of the analyzed wood processing and the cost efficiencies were calculated and analyzed based on the results obtained under real industrial conditions. The main findings are as follows: (1) when comparing the logs in the three tested diameter ranges (14–23 cm, 23–30 cm, and more than 30 cm), it can be observed that the overall material efficiency of sawing is in the range of 70%–85% and increases with the thickness of the log; (2) the share of 38 mm specialized sawn timber in the total amount of sawn timber was 41%–58% and increased with increasing log diameter; (3) the economic efficiency of the technological process is 170%–290%, based on the log size and the technology of further processing employed. The determining factor affecting cost efficiencies is unexpected changes in raw material prices and product demand in 2022. The findings suggest that while improvements in processing technology can boost efficiency, they cannot fully offset the rise in raw wood material prices.
Urządzenie do pomiaru przestrzeni manipulacji człowieka w zakresie sił i granicznych sięgów, sposób dokonywania pomiaru przestrzeni manipulacji człowieka w zakresie granicznych sięgów i sposób dokonywania pomiaru przestrzeni manipulacji człowieka w zakresie sił
Analysis of stress development during kiln drying of beech timber
AbstractBefore use, timber must have reduced moisture content. Kiln drying causes cracking risk. This study aims to evaluate the risk of cracking during the drying of beech wood samples using the response surface methodology. Additionally, we aim to develop an empirical model that describes critical tensile stress during the early drying stages and the air parameters commonly used in kiln-drying schedules for beech timber, specifically, the effects of dry-bulb temperature (DBT) and wet-bulb depression (WBD). Nine options of drying conditions were analyzed in the study according to the Central Composite Design assumptions; they were combinations of three options of DBT (30, 40, and 50 °C) and three options of WBD (4, 5, and 6 °C). During the experiments, tangential shrinkage of the wood samples was completely restrained with a load cell that measured generated tensile drying stresses. The results of the ANOVA analysis confirmed that the DBT is the only factor significantly influencing the tensile stress at failure (σf). The second-order effect between DBT and WBD has also been confirmed. The drying condition causing the highest risk of cracking was shown using the multiple contour plots of tensile stresses and the moisture content at failure (MCf). Reliability theory was used to predict the cracking risk of wood tissue. The analysis confirmed the dependence of the cracking risk of wood tissue on drying conditions. When DBT is equal to 30 °C, the cracking risk increases as the air relative humidity (RH) decreases. However, during the drying of beech wood samples at a temperature of 50 °C, decreasing the RH in a range corresponding to the increase of WBD from 4 to 6 °C reduces the cracking risk, which is indicated by the lower moisture content at failure (MCf) of the wood samples. Graphical Abstract
Enhancing Furniture Manufacturing with 3D Scanning
Product design and manufacturing leverage 3D scanning for various applications. This study aims to investigate the effectiveness of 3D scanning in furniture production by surveying the literature and showcasing four real-world case studies. The literature review reveals that 3D data acquired from real-world objects have applications in research, rapid prototyping, restoration, and preservation of antique furniture, optimizing CNC machining processes, and measuring furniture components for quality control. The case study descriptions demonstrated the circumstances, rationale, and methodology for 3D scanning. All the case studies analyzed stem from the collaboration between the Laboratory for Product Development and Design at the Faculty of Mechanical Engineering at the University of Sarajevo and various furniture production enterprises from Bosnia and Herzegovina. The conclusions highlight that 3D scanning in the furniture sector is advantageous for developing computer-aided design models from early-stage design prototypes, validating the dimensional accuracy of manufactured components by comparing with CAD models, safeguarding and reconstructing vintage furniture, and remanufacturing formerly produced goods that lack complete technical records (reverse engineering).
