This review summarizes the existing knowledge about the mechanical properties of bamboo scrimber(BS)in literature.According to literature reviews,the strength of BS under different load modes is affected by a series o...This review summarizes the existing knowledge about the mechanical properties of bamboo scrimber(BS)in literature.According to literature reviews,the strength of BS under different load modes is affected by a series of factors,such as the type of original bamboo,growth position,resin content,treatment method and density.Therefore,different production processes can be adopted according to different requirements,and bamboo scrimbers can also be classified accordingly.In addition,this review summarizes the changes in different factors considered by scholars in the research on the mechanical properties of BS,so that readers can have an overall understanding of the existing research and make more innovative and valuable research on this basis.This review provides and discusses the conclusive observations,the current research gaps and future research directions on the mechanical properties of BS.展开更多
Metallic thin films have attracted much attention owing to their unique mechanical properties,which are widely used in micro-/nano-devices.In this review,several key topics about the thin films in the micron to nano-s...Metallic thin films have attracted much attention owing to their unique mechanical properties,which are widely used in micro-/nano-devices.In this review,several key topics about the thin films in the micron to nano-scales are covered.First,the plastic deformation mechanisms in face-centered-cubic(FCC)metals,in particular the sizedependent deformation twinning at small scales,are discussed based on a deformation-mechanism map.Microstructural evolution is then briefly discussed from the perspective of the ratio of effective-to-internal stresses,while the stress-driven grain growth is discussed based on a twinning-mediated mechanism.The last section elucidates the size-dependent mechanical properties of metallic thin films,such as yield strength,ductility and mechanical fatigue behavior.展开更多
In Senegal, particularly in the Senegal River valley, agricultural mechanization remains limited, mainly due to a lack of agricultural equipment, a lack of expertise in agricultural machinery and an apprehension of th...In Senegal, particularly in the Senegal River valley, agricultural mechanization remains limited, mainly due to a lack of agricultural equipment, a lack of expertise in agricultural machinery and an apprehension of the consequences on soil quality. To better understand agricultural mechanization of rice cultivation, this survey study has been carried out in the Senegal river valley. Precisely, this work aimed to characterize farm machinery and its effects on soil and rice cultivation. A questionnaire was administered to 304 out of 1270 farmers, spread over 8 rice-growing areas, 4 of which are located in the Podor department, three in Dagana and one in Saint-Louis. The results showed that 99.3% of farmers used motorized equipment, with 95.7% using tractor and 3.6% a power tiller. Offset tillage, which is a shallow cultivation practice carried out to break up hard soil without turning it over, was most widespread among growers (95.4%). 78.3% of the valley’s farmers felt that the machinery used to carry out tillage operations was inefficient. According to the farmers, the main constraints on the use of agricultural machinery in the valley were: the upkeep and maintenance of equipment (57%), the lack of expertise in mechanization (31%), and issues adapting machinery to local conditions (12%). Those constraints have contributed to a drop in yields in recent years, the spread of weeds on cultivated plots and the gradual degradation of the soil in the area according to 78% of farmers.展开更多
This study conducted an in-depth analysis of the current tax preferential policies for small-scale individual businesses and compared them with similar policies both domestically and internationally,aiming to reveal t...This study conducted an in-depth analysis of the current tax preferential policies for small-scale individual businesses and compared them with similar policies both domestically and internationally,aiming to reveal the advantages and disadvantages of the current system.After examining the impact of these tax preferential policies on the economic status of individual business owners and the broader social economy,this article proposes a set of innovative tax preferential strategies based on theoretical foundations.By developing these innovative strategies and clarifying their implementation paths,the aim is to promote the sustainable and healthy development of small-scale individual businesses,thereby fostering comprehensive socio-economic progress.The conclusion of this study not only summarizes policy recommendations with practical significance but also provides theoretical support for the optimization and innovation of future related systems.展开更多
Cells,tissues,and organs are constantly subjected to the action of mechanical forces from the extracellular environment-and the nervous system is no exception.Cell-intrinsic properties such as membrane lipid compositi...Cells,tissues,and organs are constantly subjected to the action of mechanical forces from the extracellular environment-and the nervous system is no exception.Cell-intrinsic properties such as membrane lipid composition,abundance of mechanosensors,and cytoskeletal dynamics make cells more or less likely to sense these forces.Intrinsic and extrinsic cues are integrated by cells and this combined information determines the rate and dynamics of membrane protrusion growth or retraction(Yamada and Sixt,2019).Cell protrusions are extensions of the plasma membrane that play crucial roles in diverse contexts such as cell migration and neuronal synapse formation.In the nervous system,neurons are highly dynamic cells that can change the size and number of their pre-and postsynaptic elements(called synaptic boutons and dendritic spines,respectively),in response to changes in the levels of synaptic activity through a process called plasticity.Synaptic plasticity is a hallmark of the nervous system and is present throughout our lives,being required for functions like memory formation or the learning of new motor skills(Minegishi et al.,2023;Pillai and Franze,2024).展开更多
This paper provides analytical diagnosis of mechanical conditions of medical waste incinerators used for healthcare waste (HCW) treatment in Tanzania. The main features assessed were types of incinerators, features of...This paper provides analytical diagnosis of mechanical conditions of medical waste incinerators used for healthcare waste (HCW) treatment in Tanzania. The main features assessed were types of incinerators, features of incinerators and incinerator house. The assessment was conducted in three levels of health care facilities (HCFs), that is, Regional, district hospitals and health centers, existed in 26 regions of Tanzania. Questionnaires, interview and checklists were used as tools for data collection. It was observed that High-Tech incinerators are mainly used in regional hospitals, while district hospital and health center use both High-Tech and De-Montfort incinerators. About 60% of the incinerators have defective doors. More than 55% of incinerators are corroded in regional and district hospitals. The chimney, top plates and grate which are good condition are 55.6% and 60% in regional hospitals and health centers, respectively. The situation is below 50% in district hospitals. The leakage of the roof and loose structures were observed in district hospitals and health center to be more than 50% of the incinerator houses. On other hand, the performance of burners and incinerator housing cleanliness are generally good. It was concluded that the incinerators in the HCFs are in bad conditions, necessitating maintenance.展开更多
Despite many efforts over two decades of independence,Timor-Leste's cereal production and agricultural productivity have decreased dramatically,reflected by high food insecurity and rural poverty.This paper analys...Despite many efforts over two decades of independence,Timor-Leste's cereal production and agricultural productivity have decreased dramatically,reflected by high food insecurity and rural poverty.This paper analyses the country's current agricultural mechanization efforts to guide future actions that aim to stimulate growth through sustainable mechanization.We combined information from scientific publications,governmental and international cooperation communications,and data collected during field missions to assess the situation.Our study provides recommendations to reverse a failed tractorization campaign and presents a comprehensive overview of a strategy,in alignment with a proposed and renewed national agricultural mechanization policy,that would enable the modernization and sustainable intensification of current food production systems in a nutrition-sensitive,climate-smart,economically viable,and gender-inclusive fashion.The recommendations suggest a focus on scale-appropriate solutions that respond to upland smallholder farmers'capacities and consider good rural transport options,with the first steps to redirect the situation already taken through a technical cooperation program between FAO and the Ministry of Agriculture.Beyond this,a reform of the current government mechanization hire schemes is needed:integrated approaches,as found from business model analyses and training exercises during field missions,are needed,that entail context-specific solutions for targeted rural communities,with special attention given to participatory extension,inclusive co-validation of technologies,and private sector-led business model development around mechanization service delivery.Finally,the authors hope the presented way forward can serve as a roadmap for smallholder farmers and developing nations in similar conditions elsewhere in the world.展开更多
The depression mechanism of sulfite ions on sphalerite and Pb^(2+)activated sphalerite in the flotation separation of galena from sphalerite still lacked in-depth insight.Therefore,the depression mechanism of sulfite ...The depression mechanism of sulfite ions on sphalerite and Pb^(2+)activated sphalerite in the flotation separation of galena from sphalerite still lacked in-depth insight.Therefore,the depression mechanism of sulfite ions on sphalerite and Pb^(2+)activated sphalerite in the flotation separation of galena from sphalerite was further systematically investigated with experiments and density functional theory(DFT)calculations.The X-ray photoelectric spectroscopy(XPS)results,DFT calculation results,and frontier molecular orbital analysis indicated that sulfite ions were difficult to be adsorbed on sphalerite surface,suggesting that sulfite ions achieved depression effects on sphalerite through other non-adsorption mechanisms.First,the oxygen content in the surface of sphalerite treated with sulfite ions in creased,which enhanced the hydrophilicity of the sphalerite and further increased the difference in hydrophilicity between sphalerite and galena.Then,sulfite ions were chelated with lead ions to form PbSO_(3)in solution.The hydrophilic PbSO_(3)was more easily adsorbed on sphalerite than galena.The interaction between sulfite ions and lead ions could effectively inhibit the activation of sphalerite.In addition the UV spectrum showed that after adding sulfite ions,the peak of perxanthate in the sphalerite treated xanthate solution was significantly stronger than that in the galena with xanthate solution,indicating that xanthate interacted more readily with sulfite ions and oxygen mo lecules within the sphalerite system,leading to the formation of perxanthate.However,sulfite ions hardly depressed the flotation of ga lena and could promote the flotation of galena to some extent.This study deepened the understanding of the depression mechanism o sulfite ions on sphalerite and Pb^(2+)activated sphalerite.展开更多
The feasibility of manufacturing Ti-6Al-4V samples through a combination of laser-aided additive manufacturing with powder(LAAM_(p))and wire(LAAM_(w))was explored.A process study was first conducted to successfully ci...The feasibility of manufacturing Ti-6Al-4V samples through a combination of laser-aided additive manufacturing with powder(LAAM_(p))and wire(LAAM_(w))was explored.A process study was first conducted to successfully circumvent defects in Ti-6Al-4V deposits for LAAM_(p) and LAAM_(w),respectively.With the optimized process parameters,robust interfaces were achieved between powder/wire deposits and the forged substrate,as well as between powder and wire deposits.Microstructure characterization results revealed the epitaxial prior β grains in the deposited Ti-6Al-4V,wherein the powder deposit was dominated by a finerα′microstructure and the wire deposit was characterized by lamellar α phases.The mechanisms of microstructure formation and correlation with mechanical behavior were analyzed and discussed.The mechanical properties of the interfacial samples can meet the requirements of the relevant Aerospace Material Specifications(AMS 6932)even without post heat treatment.No fracture occurred within the interfacial area,further suggesting the robust interface.The findings of this study highlighted the feasibility of combining LAAM_(p) and LAAM_(w) in the direct manufacturing of Ti-6Al-4V parts in accordance with the required dimensional resolution and deposition rate,together with sound strength and ductility balance in the as-built condition.展开更多
A recent study by Wang et al,published in the World Journal of Psychiatry,provided preventative and therapeutic strategies for the comorbidity of obesity and depression.The gut-brain axis,which acts as a two-way commu...A recent study by Wang et al,published in the World Journal of Psychiatry,provided preventative and therapeutic strategies for the comorbidity of obesity and depression.The gut-brain axis,which acts as a two-way communication system between the gastrointestinal tract and the central nervous system,plays a pivotal role in the pathogenesis of these conditions.Evidence suggests that metabolic byproducts,such as short-chain fatty acids,lipopolysaccharide and bile acids,which are generated by the gut microbiota,along with neurotransmitters and inflammatory mediators within the gut-brain axis,modulate the host's metabolic processes,neuronal regulation,and immune responses through diverse mechanisms.The interaction between obesity and depression via the gut-brain axis involves disruptions in the gut microbiota balance,inflammatory immune responses,and alterations in the neuroendocrine system.Modulating the gut-brain axis,for example,through a ketogenic diet,the use of probiotics,and the supplementation of antioxidants,offers new remedial approaches for obesity and depression.Future research that explores the mechanisms of the gut-brain axis is needed to provide more evidence for clinical treatment.展开更多
Microstructure,texture,and mechanical properties of the extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy were investigated at different extrusion temperatures(260 and 320℃),extrusion ratios(10:1,15:1,and 30:1),and extrusi...Microstructure,texture,and mechanical properties of the extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy were investigated at different extrusion temperatures(260 and 320℃),extrusion ratios(10:1,15:1,and 30:1),and extrusion speeds(3 and 6 mm/s).The experimental results exhibited that the grain sizes after extrusion were much finer than that of the homogenized alloy,and the second phase showed streamline distribution along the extrusion direction(ED).With extrusion temperature increased from 260 to 320℃,the microstructure,texture,and mechanical properties of alloys changed slightly.The dynamic recrystallization(DRX)degree and grain sizes enhanced as the extrusion ratio increased from 10:1 to 30:1,and the strength gradually decreased but elongation(EL)increased.With the extrusion speed increased from 3 to 6 mm/s,the grain sizes and DRX degree increased significantly,and the samples presented the typical<2111>-<1123>rare-earth(RE)textures.The alloy extruded at 260℃ with extrusion ratio of 10:1 and extrusion speed of 3 mm/s showed the tensile yield strength(TYS)of 213 MPa and EL of 30.6%.After quantitatively analyzing the contribution of strengthening mechanisms,it was found that the grain boundary strengthening and dislocation strengthening played major roles among strengthening contributions.These results provide some guidelines for enlarging the industrial application of extruded Mg-RE alloy.展开更多
Ti-6Al-4Zr-2Sn-6Mo alloy is one of the most recent titanium alloys processed using powder bed fusion-laser beam(PBF-LB)technology.This alloy has the potential to replace Ti-6Al-4V in automotive and aerospace applicati...Ti-6Al-4Zr-2Sn-6Mo alloy is one of the most recent titanium alloys processed using powder bed fusion-laser beam(PBF-LB)technology.This alloy has the potential to replace Ti-6Al-4V in automotive and aerospace applications,given its superior mechanical properties,which are approximately 10%higher in terms of ultimate tensile strength(UTS)and yield strength after appropriate heat treatment.In as-built conditions,the alloy is characterized by the presence of soft orthorhombicα″martensite,necessitating a postprocessing heat treatment to decompose this phase and enhance the mechanical properties of the alloy.Usually,PBFed Ti6246 components undergo an annealing process that transforms theα″martensite into anα-βlamellar microstructure.The primary objective of this research was to develop a solution treatment and aging(STA)heat treatment tailored to the unique microstructure produced by the additive manufacturing process to achieve an ultrafine bilamellar microstructure reinforced by precipitation hardening.This study investigated the effects of various solution temperatures in theα-βfield(ranging from 800 to 875℃),cooling media(air and water),and aging time to determine the optimal heat treatment parameters for achieving the desired bilamellar microstructure.For each heat treatment condition,differentα-βmicrostructures were found,varying in terms of theα/βratio and the size of the primaryα-phase lamellae.Particular attention was given to how these factors were influenced by increases in solution temperature and how microhardness correlated with the percentage of the metastableβphase present after quenching.Tensile tests were performed on samples subjected to the most promising heat treatment parameters.A comparison with literature data revealed that the optimized STA treatment enhanced hardness and UTS by13%and 23%,respectively,compared with those of the annealed alloy.Fracture surface analyses were conducted to investigate fracture mechanisms.展开更多
The study by Yang et al presents a comprehensive investigation into the thera-peutic potential of curcumin for gastric cancer(GC).Using network pharma-cology,the researchers identified 48 curcumin-related genes,31 of ...The study by Yang et al presents a comprehensive investigation into the thera-peutic potential of curcumin for gastric cancer(GC).Using network pharma-cology,the researchers identified 48 curcumin-related genes,31 of which overlap with GC targets.Key genes,including ESR1,EGFR,CYP3A4,MAPK14,CYP1A2,and CYP2B6,are linked to poor survival in GC patients.Molecular docking con-firmed strong binding affinity of curcumin to these genes.In vitro experiments demonstrated that curcumin effectively inhibits the growth and proliferation of BGC-823,suggesting its therapeutic potential in GC through multiple targets and pathways.展开更多
The complex morphological,anatomical,physiological,and chemical mechanisms within the aging brain have been the hot topic of research for centuries.The aging process alters the brain structure that affects functions a...The complex morphological,anatomical,physiological,and chemical mechanisms within the aging brain have been the hot topic of research for centuries.The aging process alters the brain structure that affects functions and cognitions,but the worsening of such processes contributes to the pathogenesis of neurodegenerative disorders,such as Alzheimer's disease.Beyond these observable,mild morphological shifts,significant functional modifications in neurotransmission and neuronal activity critically influence the aging brain.Understanding these changes is important for maintaining cognitive health,especially given the increasing prevalence of age-related conditions that affect cognition.This review aims to explore the age-induced changes in brain plasticity and molecular processes,differentiating normal aging from the pathogenesis of Alzheimer's disease,thereby providing insights into predicting the risk of dementia,particularly Alzheimer's disease.展开更多
Small-scaled wind turbine is converted to mechanical power of windmill to electric power by generator. However almost all studies seems to have overlooked converting relation of mechanical & electric power. It the...Small-scaled wind turbine is converted to mechanical power of windmill to electric power by generator. However almost all studies seems to have overlooked converting relation of mechanical & electric power. It the reason for was very difficult establishing wind turbine system. In this paper, it is define equation of converting relation of mechanical & electric power. And it is verified by experimental methods. Defined equation will be used in developing electric devices such as inverter and controller in wind turbines. In addition this method can be used in the fields that utilize the rotational power into electrical power through generator.展开更多
The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious materials.Consequently,the true triaxial compressio...The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious materials.Consequently,the true triaxial compression tests,CT scanning,SEM,and EDS tests were conducted on cemented gangue backfill samples(CGBSs)with various carbon nanotube concentrations(P_(CNT))that satisfied fractal theory for the PSD of aggregates.The mechanical properties,energy dissipations,and failure mechanisms of the CGBSs under true triaxial compression were systematically analyzed.The results indicate that appropriate carbon nanotubes(CNTs)effectively enhance the mechanical properties and energy dissipations of CGBSs through micropore filling and microcrack bridging,and the optimal effect appears at P_(CNT)of 0.08wt%.Taking PSD fractal dimension(D)of 2.500 as an example,compared to that of CGBS without CNT,the peak strength(σ_(p)),axial peak strain(ε_(1,p)),elastic strain energy(Ue),and dissipated energy(U_(d))increased by 12.76%,29.60%,19.05%,and90.39%,respectively.However,excessive CNTs can reduce the mechanical properties of CGBSs due to CNT agglomeration,manifesting a decrease inρ_(p),ε_(1,p),and the volumetric strain increment(Δε_(v))when P_(CNT)increases from 0.08wt%to 0.12wt%.Moreover,the addition of CNTs improved the integrity of CGBS after macroscopic failure,and crack extension in CGBSs appeared in two modes:detour and pass through the aggregates.Theσ_(p)and U_(d)firstly increase and then decrease with increasing D,and porosity shows the opposite trend.Theε_(1,p)andΔε_(v)are negatively correlated with D,and CGBS with D=2.150 has the maximum deformation parameters(ε_(1,p)=0.05079,Δε_(v)=0.01990)due to the frictional slip effect caused by coarse aggregates.With increasing D,the failure modes of CGBSs are sequentially manifested as oblique shear failure,"Y-shaped"shear failure,and conjugate shear failure.展开更多
Regulated cell death is a form of cell death that is actively controlled by biomolecules.Several studies have shown that regulated cell death plays a key role after spinal cord injury.Pyroptosis and ferroptosis are ne...Regulated cell death is a form of cell death that is actively controlled by biomolecules.Several studies have shown that regulated cell death plays a key role after spinal cord injury.Pyroptosis and ferroptosis are newly discovered types of regulated cell deaths that have been shown to exacerbate inflammation and lead to cell death in damaged spinal cords.Autophagy,a complex form of cell death that is interconnected with various regulated cell death mechanisms,has garnered significant attention in the study of spinal cord injury.This injury triggers not only cell death but also cellular survival responses.Multiple signaling pathways play pivotal roles in influencing the processes of both deterioration and repair in spinal cord injury by regulating pyroptosis,ferroptosis,and autophagy.Therefore,this review aims to comprehensively examine the mechanisms underlying regulated cell deaths,the signaling pathways that modulate these mechanisms,and the potential therapeutic targets for spinal cord injury.Our analysis suggests that targeting the common regulatory signaling pathways of different regulated cell deaths could be a promising strategy to promote cell survival and enhance the repair of spinal cord injury.Moreover,a holistic approach that incorporates multiple regulated cell deaths and their regulatory pathways presents a promising multi-target therapeutic strategy for the management of spinal cord injury.展开更多
Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and petroleum.To achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emp...Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and petroleum.To achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emphasis on structural durability and monitoring is required.This study focuses on the mechanical vibrations that occur in rotary drilling systems,which have a substantial impact on the structural integrity of drilling equipment.The study specifically investigates axial,torsional,and lateral vibrations,which might lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency stick-slip.These events not only hinder the efficiency of drilling but also lead to exhaustion and harm to the system’s components since they are difficult to be detected and controlled in real time.The study investigates the dynamic interactions of these vibrations,specifically in their high-frequency modes,usingfield data obtained from measurement while drilling.Thefindings have demonstrated the effect of strong coupling between the high-frequency modes of these vibrations on drilling sys-tem performance.The obtained results highlight the importance of considering the interconnected impacts of these vibrations when designing and implementing robust control systems.Therefore,integrating these compo-nents can increase the durability of drill bits and drill strings,as well as improve the ability to monitor and detect damage.Moreover,by exploiting thesefindings,the assessment of structural resilience in rotary drilling systems can be enhanced.Furthermore,the study demonstrates the capacity of structural health monitoring to improve the quality,dependability,and efficiency of rotary drilling systems in the petroleum industry.展开更多
[Objectives]Current hybrid rice seed production mechanization and a new kind of hybrid rice seed production mechanization using Bentazone sensitive lethal genes for mechanized seed production technology are introduced...[Objectives]Current hybrid rice seed production mechanization and a new kind of hybrid rice seed production mechanization using Bentazone sensitive lethal genes for mechanized seed production technology are introduced in this paper.[Method]Sensitive Restorer Bentazone lethal dose of filtering,parental and seed weight are bred combinations of several aspects of the system described,and presented mechanized seed technology new research directions.[Results]The method of using Bentazone sensitive lethal genes for mechanized seed production technology is feasible,economic,seed production and combination advantages.[Conclusions] Using Bentazone sensitive lethal genes for mechanized seed production technology is the new study direction of mechanic production.展开更多
The small-scale drilling technique can be a fast and reliable method to estimate rock strength parameters. It needs to link the operational drilling parameters and strength properties of rock. The parameters such as b...The small-scale drilling technique can be a fast and reliable method to estimate rock strength parameters. It needs to link the operational drilling parameters and strength properties of rock. The parameters such as bit geometry, bit movement, contact frictions and crushed zone affect the estimated parameters.An analytical model considering operational drilling data and effective parameters can be used for these purposes. In this research, an analytical model was developed based on limit equilibrium of forces in a Tshaped drag bit considering the effective parameters such as bit geometry, crushed zone and contact frictions in drilling process. Based on the model, a method was used to estimate rock strength parameters such as cohesion, internal friction angle and uniaxial compressive strength of different rock types from operational drilling data. Some drilling tests were conducted by a portable and powerful drilling machine which was developed for this work. The obtained results for strength properties of different rock types from the drilling experiments based on the proposed model are in good agreement with the results of standard tests. Experimental results show that the contact friction between the cutting face and rock is close to that between bit end wearing face and rock due to the same bit material. In this case,the strength parameters, especially internal friction angle and cohesion, are estimated only by using a blunt bit drilling data and the bit bluntness does not affect the estimated results.展开更多
基金the National Natural Science Foundation of China(Nos.51878354&51308301)the Natural Science Foundation of Jiangsu Province(Nos.BK20181402&BK20130978)+2 种基金333 Talent High-Level Project of Jiangsu ProvinceQinglan Project of Jiangsu Higher Education Institutionsand the Ministry of Housing and Urban-Rural Science Project of Jiangsu Province under Grant(No.2021ZD10).
文摘This review summarizes the existing knowledge about the mechanical properties of bamboo scrimber(BS)in literature.According to literature reviews,the strength of BS under different load modes is affected by a series of factors,such as the type of original bamboo,growth position,resin content,treatment method and density.Therefore,different production processes can be adopted according to different requirements,and bamboo scrimbers can also be classified accordingly.In addition,this review summarizes the changes in different factors considered by scholars in the research on the mechanical properties of BS,so that readers can have an overall understanding of the existing research and make more innovative and valuable research on this basis.This review provides and discusses the conclusive observations,the current research gaps and future research directions on the mechanical properties of BS.
基金supported by the National Key Research and Development Program of China(2017YFA0700701,2017YFB0702301)the National Natural Science Foundation of China(Grant Nos.51621063,51722104,51625103,51790482,51761135031 and 51571157)+2 种基金the 111 Project 2.0 of China(BP2018008),the Fok Ying Tong Education Foundation(161096)the Shaanxi Province innovative talents promotion Projects(2018KJXX-004)the Fundamental Research Funds for the Central Universities.
文摘Metallic thin films have attracted much attention owing to their unique mechanical properties,which are widely used in micro-/nano-devices.In this review,several key topics about the thin films in the micron to nano-scales are covered.First,the plastic deformation mechanisms in face-centered-cubic(FCC)metals,in particular the sizedependent deformation twinning at small scales,are discussed based on a deformation-mechanism map.Microstructural evolution is then briefly discussed from the perspective of the ratio of effective-to-internal stresses,while the stress-driven grain growth is discussed based on a twinning-mediated mechanism.The last section elucidates the size-dependent mechanical properties of metallic thin films,such as yield strength,ductility and mechanical fatigue behavior.
文摘In Senegal, particularly in the Senegal River valley, agricultural mechanization remains limited, mainly due to a lack of agricultural equipment, a lack of expertise in agricultural machinery and an apprehension of the consequences on soil quality. To better understand agricultural mechanization of rice cultivation, this survey study has been carried out in the Senegal river valley. Precisely, this work aimed to characterize farm machinery and its effects on soil and rice cultivation. A questionnaire was administered to 304 out of 1270 farmers, spread over 8 rice-growing areas, 4 of which are located in the Podor department, three in Dagana and one in Saint-Louis. The results showed that 99.3% of farmers used motorized equipment, with 95.7% using tractor and 3.6% a power tiller. Offset tillage, which is a shallow cultivation practice carried out to break up hard soil without turning it over, was most widespread among growers (95.4%). 78.3% of the valley’s farmers felt that the machinery used to carry out tillage operations was inefficient. According to the farmers, the main constraints on the use of agricultural machinery in the valley were: the upkeep and maintenance of equipment (57%), the lack of expertise in mechanization (31%), and issues adapting machinery to local conditions (12%). Those constraints have contributed to a drop in yields in recent years, the spread of weeds on cultivated plots and the gradual degradation of the soil in the area according to 78% of farmers.
文摘This study conducted an in-depth analysis of the current tax preferential policies for small-scale individual businesses and compared them with similar policies both domestically and internationally,aiming to reveal the advantages and disadvantages of the current system.After examining the impact of these tax preferential policies on the economic status of individual business owners and the broader social economy,this article proposes a set of innovative tax preferential strategies based on theoretical foundations.By developing these innovative strategies and clarifying their implementation paths,the aim is to promote the sustainable and healthy development of small-scale individual businesses,thereby fostering comprehensive socio-economic progress.The conclusion of this study not only summarizes policy recommendations with practical significance but also provides theoretical support for the optimization and innovation of future related systems.
基金supported by PTDC-01778/2022-NeuroDev3D,iNOVA4Health(UIDB/04462/2020 and UIDP/04462/2020)LS4FUTURE(LA/P/0087/2020)。
文摘Cells,tissues,and organs are constantly subjected to the action of mechanical forces from the extracellular environment-and the nervous system is no exception.Cell-intrinsic properties such as membrane lipid composition,abundance of mechanosensors,and cytoskeletal dynamics make cells more or less likely to sense these forces.Intrinsic and extrinsic cues are integrated by cells and this combined information determines the rate and dynamics of membrane protrusion growth or retraction(Yamada and Sixt,2019).Cell protrusions are extensions of the plasma membrane that play crucial roles in diverse contexts such as cell migration and neuronal synapse formation.In the nervous system,neurons are highly dynamic cells that can change the size and number of their pre-and postsynaptic elements(called synaptic boutons and dendritic spines,respectively),in response to changes in the levels of synaptic activity through a process called plasticity.Synaptic plasticity is a hallmark of the nervous system and is present throughout our lives,being required for functions like memory formation or the learning of new motor skills(Minegishi et al.,2023;Pillai and Franze,2024).
文摘This paper provides analytical diagnosis of mechanical conditions of medical waste incinerators used for healthcare waste (HCW) treatment in Tanzania. The main features assessed were types of incinerators, features of incinerators and incinerator house. The assessment was conducted in three levels of health care facilities (HCFs), that is, Regional, district hospitals and health centers, existed in 26 regions of Tanzania. Questionnaires, interview and checklists were used as tools for data collection. It was observed that High-Tech incinerators are mainly used in regional hospitals, while district hospital and health center use both High-Tech and De-Montfort incinerators. About 60% of the incinerators have defective doors. More than 55% of incinerators are corroded in regional and district hospitals. The chimney, top plates and grate which are good condition are 55.6% and 60% in regional hospitals and health centers, respectively. The situation is below 50% in district hospitals. The leakage of the roof and loose structures were observed in district hospitals and health center to be more than 50% of the incinerator houses. On other hand, the performance of burners and incinerator housing cleanliness are generally good. It was concluded that the incinerators in the HCFs are in bad conditions, necessitating maintenance.
文摘Despite many efforts over two decades of independence,Timor-Leste's cereal production and agricultural productivity have decreased dramatically,reflected by high food insecurity and rural poverty.This paper analyses the country's current agricultural mechanization efforts to guide future actions that aim to stimulate growth through sustainable mechanization.We combined information from scientific publications,governmental and international cooperation communications,and data collected during field missions to assess the situation.Our study provides recommendations to reverse a failed tractorization campaign and presents a comprehensive overview of a strategy,in alignment with a proposed and renewed national agricultural mechanization policy,that would enable the modernization and sustainable intensification of current food production systems in a nutrition-sensitive,climate-smart,economically viable,and gender-inclusive fashion.The recommendations suggest a focus on scale-appropriate solutions that respond to upland smallholder farmers'capacities and consider good rural transport options,with the first steps to redirect the situation already taken through a technical cooperation program between FAO and the Ministry of Agriculture.Beyond this,a reform of the current government mechanization hire schemes is needed:integrated approaches,as found from business model analyses and training exercises during field missions,are needed,that entail context-specific solutions for targeted rural communities,with special attention given to participatory extension,inclusive co-validation of technologies,and private sector-led business model development around mechanization service delivery.Finally,the authors hope the presented way forward can serve as a roadmap for smallholder farmers and developing nations in similar conditions elsewhere in the world.
基金financially supported by the National Natural Science Foundation of China(No.52074356)Open Foundation of State Key Laboratory of Mineral Processing(No.BGRIMM-KJSKL-2023-06)+5 种基金the National Key R&D Program of China(No.2022YFC2904500)the Science and Technology Innovation Program of Hunan Province,China(No.2022RC1183)Changsha Science and Technology Project,China(Outstanding Innovative Youth Training Program)Innovation driven program of Central South University(No.2023CXQD002)National 111 Project(No.B14034)the Fundamental Research Funds for the Central Universities of Central South University Project(No.50621747)。
文摘The depression mechanism of sulfite ions on sphalerite and Pb^(2+)activated sphalerite in the flotation separation of galena from sphalerite still lacked in-depth insight.Therefore,the depression mechanism of sulfite ions on sphalerite and Pb^(2+)activated sphalerite in the flotation separation of galena from sphalerite was further systematically investigated with experiments and density functional theory(DFT)calculations.The X-ray photoelectric spectroscopy(XPS)results,DFT calculation results,and frontier molecular orbital analysis indicated that sulfite ions were difficult to be adsorbed on sphalerite surface,suggesting that sulfite ions achieved depression effects on sphalerite through other non-adsorption mechanisms.First,the oxygen content in the surface of sphalerite treated with sulfite ions in creased,which enhanced the hydrophilicity of the sphalerite and further increased the difference in hydrophilicity between sphalerite and galena.Then,sulfite ions were chelated with lead ions to form PbSO_(3)in solution.The hydrophilic PbSO_(3)was more easily adsorbed on sphalerite than galena.The interaction between sulfite ions and lead ions could effectively inhibit the activation of sphalerite.In addition the UV spectrum showed that after adding sulfite ions,the peak of perxanthate in the sphalerite treated xanthate solution was significantly stronger than that in the galena with xanthate solution,indicating that xanthate interacted more readily with sulfite ions and oxygen mo lecules within the sphalerite system,leading to the formation of perxanthate.However,sulfite ions hardly depressed the flotation of ga lena and could promote the flotation of galena to some extent.This study deepened the understanding of the depression mechanism o sulfite ions on sphalerite and Pb^(2+)activated sphalerite.
基金financially supported by the Agency for Science,Technology and Research(A*Star),Republic of Singapore,under the Aerospace Consortium Cycle 12“Characterization of the Effect of Wire and Powder Deposited Materials”(No.A1815a0078)。
文摘The feasibility of manufacturing Ti-6Al-4V samples through a combination of laser-aided additive manufacturing with powder(LAAM_(p))and wire(LAAM_(w))was explored.A process study was first conducted to successfully circumvent defects in Ti-6Al-4V deposits for LAAM_(p) and LAAM_(w),respectively.With the optimized process parameters,robust interfaces were achieved between powder/wire deposits and the forged substrate,as well as between powder and wire deposits.Microstructure characterization results revealed the epitaxial prior β grains in the deposited Ti-6Al-4V,wherein the powder deposit was dominated by a finerα′microstructure and the wire deposit was characterized by lamellar α phases.The mechanisms of microstructure formation and correlation with mechanical behavior were analyzed and discussed.The mechanical properties of the interfacial samples can meet the requirements of the relevant Aerospace Material Specifications(AMS 6932)even without post heat treatment.No fracture occurred within the interfacial area,further suggesting the robust interface.The findings of this study highlighted the feasibility of combining LAAM_(p) and LAAM_(w) in the direct manufacturing of Ti-6Al-4V parts in accordance with the required dimensional resolution and deposition rate,together with sound strength and ductility balance in the as-built condition.
文摘A recent study by Wang et al,published in the World Journal of Psychiatry,provided preventative and therapeutic strategies for the comorbidity of obesity and depression.The gut-brain axis,which acts as a two-way communication system between the gastrointestinal tract and the central nervous system,plays a pivotal role in the pathogenesis of these conditions.Evidence suggests that metabolic byproducts,such as short-chain fatty acids,lipopolysaccharide and bile acids,which are generated by the gut microbiota,along with neurotransmitters and inflammatory mediators within the gut-brain axis,modulate the host's metabolic processes,neuronal regulation,and immune responses through diverse mechanisms.The interaction between obesity and depression via the gut-brain axis involves disruptions in the gut microbiota balance,inflammatory immune responses,and alterations in the neuroendocrine system.Modulating the gut-brain axis,for example,through a ketogenic diet,the use of probiotics,and the supplementation of antioxidants,offers new remedial approaches for obesity and depression.Future research that explores the mechanisms of the gut-brain axis is needed to provide more evidence for clinical treatment.
基金supported by the National Science and Technology Major Project,China(No.2019-VI-0004-0118)the National Natural Science Foundation of China(No.51771152)the National Key R&D Program of China(No.2018YFB1106800)。
文摘Microstructure,texture,and mechanical properties of the extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy were investigated at different extrusion temperatures(260 and 320℃),extrusion ratios(10:1,15:1,and 30:1),and extrusion speeds(3 and 6 mm/s).The experimental results exhibited that the grain sizes after extrusion were much finer than that of the homogenized alloy,and the second phase showed streamline distribution along the extrusion direction(ED).With extrusion temperature increased from 260 to 320℃,the microstructure,texture,and mechanical properties of alloys changed slightly.The dynamic recrystallization(DRX)degree and grain sizes enhanced as the extrusion ratio increased from 10:1 to 30:1,and the strength gradually decreased but elongation(EL)increased.With the extrusion speed increased from 3 to 6 mm/s,the grain sizes and DRX degree increased significantly,and the samples presented the typical<2111>-<1123>rare-earth(RE)textures.The alloy extruded at 260℃ with extrusion ratio of 10:1 and extrusion speed of 3 mm/s showed the tensile yield strength(TYS)of 213 MPa and EL of 30.6%.After quantitatively analyzing the contribution of strengthening mechanisms,it was found that the grain boundary strengthening and dislocation strengthening played major roles among strengthening contributions.These results provide some guidelines for enlarging the industrial application of extruded Mg-RE alloy.
基金financed by the European Union-Next Generation EU(National Sustainable Mobility Center CN00000023,Italian Ministry of University and Research Decree n.1033-17/06/2022,Spoke 11-Innovative Materials&Lightweighting)。
文摘Ti-6Al-4Zr-2Sn-6Mo alloy is one of the most recent titanium alloys processed using powder bed fusion-laser beam(PBF-LB)technology.This alloy has the potential to replace Ti-6Al-4V in automotive and aerospace applications,given its superior mechanical properties,which are approximately 10%higher in terms of ultimate tensile strength(UTS)and yield strength after appropriate heat treatment.In as-built conditions,the alloy is characterized by the presence of soft orthorhombicα″martensite,necessitating a postprocessing heat treatment to decompose this phase and enhance the mechanical properties of the alloy.Usually,PBFed Ti6246 components undergo an annealing process that transforms theα″martensite into anα-βlamellar microstructure.The primary objective of this research was to develop a solution treatment and aging(STA)heat treatment tailored to the unique microstructure produced by the additive manufacturing process to achieve an ultrafine bilamellar microstructure reinforced by precipitation hardening.This study investigated the effects of various solution temperatures in theα-βfield(ranging from 800 to 875℃),cooling media(air and water),and aging time to determine the optimal heat treatment parameters for achieving the desired bilamellar microstructure.For each heat treatment condition,differentα-βmicrostructures were found,varying in terms of theα/βratio and the size of the primaryα-phase lamellae.Particular attention was given to how these factors were influenced by increases in solution temperature and how microhardness correlated with the percentage of the metastableβphase present after quenching.Tensile tests were performed on samples subjected to the most promising heat treatment parameters.A comparison with literature data revealed that the optimized STA treatment enhanced hardness and UTS by13%and 23%,respectively,compared with those of the annealed alloy.Fracture surface analyses were conducted to investigate fracture mechanisms.
基金Supported by The College Students’Innovation and Entrepreneurship Competition,No.2024cxcy504 and No.202410459164.
文摘The study by Yang et al presents a comprehensive investigation into the thera-peutic potential of curcumin for gastric cancer(GC).Using network pharma-cology,the researchers identified 48 curcumin-related genes,31 of which overlap with GC targets.Key genes,including ESR1,EGFR,CYP3A4,MAPK14,CYP1A2,and CYP2B6,are linked to poor survival in GC patients.Molecular docking con-firmed strong binding affinity of curcumin to these genes.In vitro experiments demonstrated that curcumin effectively inhibits the growth and proliferation of BGC-823,suggesting its therapeutic potential in GC through multiple targets and pathways.
文摘The complex morphological,anatomical,physiological,and chemical mechanisms within the aging brain have been the hot topic of research for centuries.The aging process alters the brain structure that affects functions and cognitions,but the worsening of such processes contributes to the pathogenesis of neurodegenerative disorders,such as Alzheimer's disease.Beyond these observable,mild morphological shifts,significant functional modifications in neurotransmission and neuronal activity critically influence the aging brain.Understanding these changes is important for maintaining cognitive health,especially given the increasing prevalence of age-related conditions that affect cognition.This review aims to explore the age-induced changes in brain plasticity and molecular processes,differentiating normal aging from the pathogenesis of Alzheimer's disease,thereby providing insights into predicting the risk of dementia,particularly Alzheimer's disease.
文摘Small-scaled wind turbine is converted to mechanical power of windmill to electric power by generator. However almost all studies seems to have overlooked converting relation of mechanical & electric power. It the reason for was very difficult establishing wind turbine system. In this paper, it is define equation of converting relation of mechanical & electric power. And it is verified by experimental methods. Defined equation will be used in developing electric devices such as inverter and controller in wind turbines. In addition this method can be used in the fields that utilize the rotational power into electrical power through generator.
基金financially supported by the National Natural Science Foundation of China(Nos.52174092,51904290,and 52374147)the Natural Science Foundation of Jiangsu Province,China(No.BK20220157)+2 种基金the Fundamental Research Funds for the Central Universities,China(No.2022YCPY0202)the National Key Research and Development Program of China(No.2023YFC3804204)the Major Program of Xinjiang Uygur Autonomous Region S cience and Technology(No.2023A01002)。
文摘The mechanical behavior of cemented gangue backfill materials(CGBMs)is closely related to particle size distribution(PSD)of aggregates and properties of cementitious materials.Consequently,the true triaxial compression tests,CT scanning,SEM,and EDS tests were conducted on cemented gangue backfill samples(CGBSs)with various carbon nanotube concentrations(P_(CNT))that satisfied fractal theory for the PSD of aggregates.The mechanical properties,energy dissipations,and failure mechanisms of the CGBSs under true triaxial compression were systematically analyzed.The results indicate that appropriate carbon nanotubes(CNTs)effectively enhance the mechanical properties and energy dissipations of CGBSs through micropore filling and microcrack bridging,and the optimal effect appears at P_(CNT)of 0.08wt%.Taking PSD fractal dimension(D)of 2.500 as an example,compared to that of CGBS without CNT,the peak strength(σ_(p)),axial peak strain(ε_(1,p)),elastic strain energy(Ue),and dissipated energy(U_(d))increased by 12.76%,29.60%,19.05%,and90.39%,respectively.However,excessive CNTs can reduce the mechanical properties of CGBSs due to CNT agglomeration,manifesting a decrease inρ_(p),ε_(1,p),and the volumetric strain increment(Δε_(v))when P_(CNT)increases from 0.08wt%to 0.12wt%.Moreover,the addition of CNTs improved the integrity of CGBS after macroscopic failure,and crack extension in CGBSs appeared in two modes:detour and pass through the aggregates.Theσ_(p)and U_(d)firstly increase and then decrease with increasing D,and porosity shows the opposite trend.Theε_(1,p)andΔε_(v)are negatively correlated with D,and CGBS with D=2.150 has the maximum deformation parameters(ε_(1,p)=0.05079,Δε_(v)=0.01990)due to the frictional slip effect caused by coarse aggregates.With increasing D,the failure modes of CGBSs are sequentially manifested as oblique shear failure,"Y-shaped"shear failure,and conjugate shear failure.
基金supported by the Natural Science Foundation of Fujian Province,No.2021J02035(to WX).
文摘Regulated cell death is a form of cell death that is actively controlled by biomolecules.Several studies have shown that regulated cell death plays a key role after spinal cord injury.Pyroptosis and ferroptosis are newly discovered types of regulated cell deaths that have been shown to exacerbate inflammation and lead to cell death in damaged spinal cords.Autophagy,a complex form of cell death that is interconnected with various regulated cell death mechanisms,has garnered significant attention in the study of spinal cord injury.This injury triggers not only cell death but also cellular survival responses.Multiple signaling pathways play pivotal roles in influencing the processes of both deterioration and repair in spinal cord injury by regulating pyroptosis,ferroptosis,and autophagy.Therefore,this review aims to comprehensively examine the mechanisms underlying regulated cell deaths,the signaling pathways that modulate these mechanisms,and the potential therapeutic targets for spinal cord injury.Our analysis suggests that targeting the common regulatory signaling pathways of different regulated cell deaths could be a promising strategy to promote cell survival and enhance the repair of spinal cord injury.Moreover,a holistic approach that incorporates multiple regulated cell deaths and their regulatory pathways presents a promising multi-target therapeutic strategy for the management of spinal cord injury.
文摘Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and petroleum.To achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emphasis on structural durability and monitoring is required.This study focuses on the mechanical vibrations that occur in rotary drilling systems,which have a substantial impact on the structural integrity of drilling equipment.The study specifically investigates axial,torsional,and lateral vibrations,which might lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency stick-slip.These events not only hinder the efficiency of drilling but also lead to exhaustion and harm to the system’s components since they are difficult to be detected and controlled in real time.The study investigates the dynamic interactions of these vibrations,specifically in their high-frequency modes,usingfield data obtained from measurement while drilling.Thefindings have demonstrated the effect of strong coupling between the high-frequency modes of these vibrations on drilling sys-tem performance.The obtained results highlight the importance of considering the interconnected impacts of these vibrations when designing and implementing robust control systems.Therefore,integrating these compo-nents can increase the durability of drill bits and drill strings,as well as improve the ability to monitor and detect damage.Moreover,by exploiting thesefindings,the assessment of structural resilience in rotary drilling systems can be enhanced.Furthermore,the study demonstrates the capacity of structural health monitoring to improve the quality,dependability,and efficiency of rotary drilling systems in the petroleum industry.
文摘[Objectives]Current hybrid rice seed production mechanization and a new kind of hybrid rice seed production mechanization using Bentazone sensitive lethal genes for mechanized seed production technology are introduced in this paper.[Method]Sensitive Restorer Bentazone lethal dose of filtering,parental and seed weight are bred combinations of several aspects of the system described,and presented mechanized seed technology new research directions.[Results]The method of using Bentazone sensitive lethal genes for mechanized seed production technology is feasible,economic,seed production and combination advantages.[Conclusions] Using Bentazone sensitive lethal genes for mechanized seed production technology is the new study direction of mechanic production.
文摘The small-scale drilling technique can be a fast and reliable method to estimate rock strength parameters. It needs to link the operational drilling parameters and strength properties of rock. The parameters such as bit geometry, bit movement, contact frictions and crushed zone affect the estimated parameters.An analytical model considering operational drilling data and effective parameters can be used for these purposes. In this research, an analytical model was developed based on limit equilibrium of forces in a Tshaped drag bit considering the effective parameters such as bit geometry, crushed zone and contact frictions in drilling process. Based on the model, a method was used to estimate rock strength parameters such as cohesion, internal friction angle and uniaxial compressive strength of different rock types from operational drilling data. Some drilling tests were conducted by a portable and powerful drilling machine which was developed for this work. The obtained results for strength properties of different rock types from the drilling experiments based on the proposed model are in good agreement with the results of standard tests. Experimental results show that the contact friction between the cutting face and rock is close to that between bit end wearing face and rock due to the same bit material. In this case,the strength parameters, especially internal friction angle and cohesion, are estimated only by using a blunt bit drilling data and the bit bluntness does not affect the estimated results.