Spatial and temporal variability of soil water in drylands:plant water potential as a diagnostic tool

Arid and semi-arid regions are characterized by low rainfall and high potential evaporative demand. Here, water is the major limiting factor for plant growth and productivity. Soil and surface hydrology properties （e.g. field capacity, infikration rates） effectively control the water re-distribution in the ecosystem, a fact that is aggravated in arid environments. Information of the spatial and temporal accessibility of soil water in desert ecosystems is limited. The purpose of the studies is the application of plant water potential to estimate the spatial and temporal variations of soil water availability in different arid ecosystems of the Negev （Israel） and southern Morocco. As model plants the evergreen shrubs Retama raetam, Thymelaea hirsuta and trees （Acacia tortilis） were chosen. Seasonal and spatial variations of the pre-dawn water potential （ψpd） were examined as diagnostic tool to determine water availability on the landscape level. The seasonal differences in the pre-dawn water potential were less pronounced on the dune compared to the interdune. This showed a better water availability on the dune slope. Also in the investigated wadis systems spatial differences of the water potential could be detected and related to the vegetation pattern.

Carbon Replicas of Porous Concrete Obtained by Chemical Vapor Deposition—Some Aspects of the Synthesis Mechanism

In this contribution, the template assisted synthesis of porous carbons by chemical vapor deposition in porous concrete templates has been described for the first time. Porous concrete made templates can be obtained in almost any geometrical shape and are therefore attractive templates to prepare porous carbon monoliths. The carbon deposition process in porous concrete follows a three-stage-course consisting in an initial period, a period of fast carbon deposition and a period of slow carbon deposition. The carbon growth within the template pores occurs obviously plug-like from the inner to the outer sphere. Any continuous covering of the template pore walls by carbon could not be observed. In difference to porous concrete, the carbon deposition in silica gel is strongly accompanied by mass transfer limitations. For porous concrete, such strong effect has not been observed obviously due to its hierarchical pore system. The template materials have been loaded with carbon by chemical vapor deposition in a flow reactor. The process of the template pore filling has been characterized by the time dependence of the template mass gain. The materials have been characterized by means of X-ray tomography and nitrogen adsorption at 77 K, respectively.

Advanced Welding Technology for Highly Stressable Multi-Material Designs with Fiber-Reinforced Plastics and Metals

Organic sheets made out of fiber-reinforced thermoplastics are able to make a crucial contribution to increase the lightweight potential of a design. They show high specific strength- and stiffness properties, good damping characteristics and recycling capabilities, while being able to show a higher energy absorption capacity than comparable metal constructions. Nowadays, multi-material designs are an established way in the automotive industry to combine the benefits of metal and fiber-reinforced plastics. Currently used technologies for the joining of organic sheets and metals in large-scale production are mechanical joining technologies and adhesive technologies. Both techniques require large overlapping areas that are not required in the design of the part. Additionally, mechanical joining is usually combined with “fiber-destroying” pre-drilling and punching processes. This will disturb the force flux at the joining location by causing unwanted fiber- and inter-fiber failure and inducing critical notch stresses. Therefore, the multi-material design with fiber-reinforced thermoplastics and metals needs optimized joining techniques that don’t interrupt the force flux, so that higher loads can be induced and the full benefit of the FRP material can be used. This article focuses on the characterization of a new joining technology, based on the Cold Metal Transfer (CMT) welding process that allows joining of organic sheets and metals in a load path optimized way, with short cycle times. This is achieved by redirecting the fibers around the joining area by the insertion of a thin metal pin. The path of the fibers will be similar to paths of fibers inside structures found in nature, e.g. a knothole inside of a tree. As a result of the bionic fiber design of the joint, high joining strengths can be achieved. The increase of the joint strength compared to blind riveting was performed and proven with stainless steel and orthotropic reinforced composites in shear-tests based on the DIN EN ISO 14273. Every specimen joined with the new CMT Pin joining technology showed a higher strength than specimens joined with one blind rivet. Specimens joined with two or three pin rows show a higher strength than specimens joined with two blind rivets.

Analytical-Numerical Modeling Approach for Calculation of the Structural Distortions after Welding and Thermal Straightening

The analytic-numerical hybrid model for calculating welding distortions in large welded structures is presented. Objective of the analytical model is the calculation of the plastic strains and their distribution after welding and thermal straightening process. The consideration of the essential physical relations is put into discussion. Afterwards the obtained plastic strains by the analytical calculation are loaded on an elastic FE-model of the structure and the distortions of the whole structure are predicted. The consideration of welding and thermal straightening scenarios and the assembling stages is done by taking into account the intermediate variation of the strain state at every processing step. The model is intended to be used for solving industrial tasks, i.e. intending acceptable precision and calculation time as well as low simulation costs. The application of the model is demonstrated on structures with many welds and straightening spots.

Assessment of Past and Future Land Use/Land Cover Dynamics of the Old Kumasi Metropolitan Assembly and Atwima Nwabiagya Municipal Area, Ghana

Ghana like all countries in Sub-Saharan region of Africa have long been undergoing intense land use land cover changes (LULCC) which have given rise to extensive forest loss (deforestation and degradation), loss of arable land and land degradation. This study assessed the past LULCC in the Atwima Nwabiagya which contains the Barekese and Owabi Headworks) and the old Kumasi Local Assemblies’ areas in Ghana and projected the scenario in 2040 for business-as-usual (BAU). The synergies of satellite imagery of 1990, 2000, 2010 and 2020 were classified with an overall accuracy of 90%. Markov Cellular-Automata method was used to forecast the future LULC pattern after detecting main driving forces of LULCC. The findings showed an extensive increase in built up areas from 11% in 1990 to 39% in 2020 owing largely to 23% decrease in forest cover and 6% decrease in agricultural lands within the past 30 years (1990-2020). The projected LULC under the BAU scenario for 2040 showed built-up surge from 39% to 45% indicating additional forest loss from 43% in 2020 to 40% and decreasing agricultural land from 17% to 14%. The main driver for the LULCC is clearly anthropogenic driven as the human population in the study area keeps rising every censual year. This study exemplifies the fast-tracked forest loss, loss of arable land and challenges on ecosystem sustainability of the Barekese-Owabi-Kumasi landscape. The current and projected maps necessitate the apt implementation of suitable interventions such as reforestation, protection measures and policy decision in deliberate land use planning to mitigate further loss of forest cover and safeguard the Barekese and Owabi headworks.

Urbanization and Other Land Use Land Cover Change Assessment in the Greater Kumasi Area of Ghana

Urbanization posits the expression of urban expanse expansion due to population growth, rise in built-up areas, high population density and its correspondingly urban way of life. Unrestrained impetus of development and land use land cover change (LULCC) portent several issues such as unlawful urban sprawl, loss of agricultural land, forest loss and other associated complications. This study analyzed the dynamics of urbanization and other LULCC in Ghana’s Greater Kumasi area via Landsat images (TM 1986, OLI 2013 and OLI 2023) using ERDAS Imagine, Idrisi and ArcGIS software. Implementing supervised classification technique, the Maximum Likelihood Classifier (MLC) procedure was employed to categories the study area into five LULC classes. Accuracy assessment undertaken on the resultant LULC maps was deemed very satisfactory. The results from 1986-2023 pointed to an upsurge in a built-up extent as of 8% to 41%, a decrease in Closed Forest from 9% to 4%, another decrease in Open Forests from 64% to 33%, a slight increase from 16% to 20% in farmlands and a stable level of water share. Further analysis indicated that the study area had undergone LULCC within the periods 1986-2013 and 2013-2023 at 60% and 37% respectively. The findings showed uncontrolled urban sprawling along major roads and forest loss as deforestation outside protected areas and degradation in protected forest. The monitoring of urbanization and other LULCC is important for local, and national governments and other bodies charged with the implementation of programs and policies that manage and utilize natural resources. Development adapts to mitigate the effect on the environment.

杂砂岩碱集料反应特征

杂砂岩集料所含的石英组分是引起碱集料反应的主要活性来源,研究该集料中的石英溶出及其在碱溶液中的行为特征,结果发现:石英颗粒尺寸和相应的硅溶出速度之间存在着一定的相关性,即:石英颗粒尺寸越小,其比表面积越大,同等条件下相应的硅溶出速度越大;石英颗粒的结构特征变化规律与杂砂岩试样本身的碱活性大小之间不存在相关性。集料中的铝主要来源于γ-Al2O3纳米相、黑云母和白云母,其对溶液中硅溶出的影响机理不同。集料中的铝溶出生成铝硅酸盐从而引起溶液中溶出硅含量的降低,砂浆或混凝土碱集料反应膨胀率的大小与溶液中所谓的"自由硅"含量有关,即"自由硅"含量越大,同等条件下的碱集料反应膨胀越大。这些相关性对于实际工程应用非常重要,由此可望建立评价杂砂岩碱活性敏感性的直接测试方法。研究还发现通过添加高铝粉可抑制碱集料反应产生的膨胀。

Are Ni/and Ni5Fe1/biochar catalysts suitable for synthetic natural gas production?A comparison with g-Al2O3 supported catalysts

Among challenges implicit in the transition to the post-fossil fuel energetic model,the finite amount of resources available for the technological implementation of CO_(2) revalorizing processes arises as a central issue.The development of fully renewable catalytic systems with easier metal recovery strategies would promote the viability and sustainability of synthetic natural gas production circular routes.Taking Ni and NiFe catalysts supported over g-Al_(2)O_(3) oxide as reference materials,this work evaluates the potentiality of Ni and NiFe supported biochar catalysts for CO_(2) methanation.The development of competitive biochar catalysts was found dependent on the creation of basic sites on the catalyst surface.Displaying lower Turn Over Frequencies than Ni/Al catalyst,the absence of basic sites achieved over Ni/C catalyst was related to the depleted catalyst performances.For NiFe catalysts,analogous Ni_(5)Fe_(1) alloys were constituted over both alumina and biochar supports.The highest specific activity of the catalyst series,exhibited by the NiFe/C catalyst,was related to the development of surface basic sites along with weaker NiFe-C interactions,which resulted in increased Ni0:NiO surface populations under reaction conditions.In summary,the present work establishes biochar supports as a competitive material to consider within the future low-carbon energetic panorama.

Designing a Security Architecture for a P2P Video Conference System

More and more modern group oriented collaborativeapplications use the peer-to-peer(P2P)paradigm tobe independent of expensive infrastructures as theyare,for instance,provided for audio and video conferencesby H.323 systems.Decentralized collaborativeP2P solutions require appropriate mechanismsto protect group privacy and data integrity.A centralizedclient/server based video conference system canbe well shielded in a standard manner,whilst thereare no off-the-shelf approaches to secure a P2P videoconference up to now.The paper addresses this issueand presents a flexible security architecture.Usingthe BRAVIS system[4]as an example it shows howthe architecture can be embedded into a P2P videoconferencing system.

Use of Internet Technology for the Improvement of Execution Management in Geotechnical Engineering Projects

An internet-based information and monitoring platform for the specific requirements of geotechnical engineering projects is presented. The platform is based on a hybrid-model approach consisting of a model-based information management system and a resource management system, the latter also referred to as DCMS. Project key information can be accessed via the main user interface, the 'graphical navigator'. The graphical navigator provides also a direct access to additional information in the DCMS. Prompt reac-tion in exceptional situations as well as in daily work gets an extensive support. In practical applications it has been proven that this platform seems to be an adequate tool especially for risk assessment and management in geotechnical engineering projects. Components and advantages of the platform as well as ex periences from the applications are presented and discussed in the paper.

Dimension-Reduced Model for Deep-Water Waves

Starting from the 2D Euler equations for an incompressible potential flow, a dimension-reduced model describing deep-water surface waves is derived. Similar to the Shallow-Water case, the z-dependence of the dependent variables is found explicitly from the Laplace equation and a set of two one- dimensional equations in x for the surface velocity and the surface elevation remains. The model is nonlocal and can be formulated in conservative form, describing waves over an infinitely deep layer. Finally, numerical solutions are presented for several initial conditions. The side-band instability of Stokes waves and stable envelope solitons are obtained in agreement with other work. The conservation of the total energy is checked.

Impacts of Soil Additives on Crop Yield and C-Sequestration in Post Mine Substrates of Lusatia,Germany

Opencast lignite mining in the Lusatia region of Germany has resulted in large scale landscape disturbances, which require suitable recultivation techniques in order to promote plant growth and establishment in the remaining nutrient-poor substrates with low water-holding capacity. Thus, the effects of two commercial soil additives （CSA）, a hydrophilic polymer mixed with volcanic rock flour and bentonite （a-CSA）, and digester solids from biogas plants enriched with humic acids and bentonite （b-CSA）, on soil organic carbon （SOC） storage, plant yields and root biomass were assessed after cultivating perennial crops （Dactylis 9lornerata L.） in monoculture and Helianthus annuus L.-Brassica napus L. in crop rotation systems. The CSA were incorporated into the top 20 cm soil depth using a rotary spader. The results indicated that a-CSA led to a significant increase in plant yield during the first year, and improved root biomass in the following year. As a result, SOC stocks increased, especially in the 0 10 cm soil layer. No significant sequestration of additional SOC was observed on b-CSA-amended plots at the end of both years. Bulk density values decreased in all treatments under the monoculture system. It can be concluded that application of a-CSA enhanced soil water availability for plant uptake and consequently promoted plant growth and organic carbon sequestration. The relative enrichment of organic matter without effects on water-holding capacities of b-CSA treatments suggested that it was not suitable for rapid land reclamation.

Verification of Authentication Protocols for Epistemic Goals via SAT Compilation

This paper introduces a new methodology for epistemic logic, to analyze communication protocols that uses knowledge structures, a specific form of Kripke semantics over hostile networks. The paper particularly focuses on automatic verification of authentication protocols. Our approach is based on the actual definitions of a protocol, not on some difficultto-establish justifications. The proposed methodology is different from many previous approaches to automatic verification of security protocols in that it is justification-oriented instead of falsification-oriented, i.e., finding bugs in a protocol. The main idea is based on observations： separating a principal executing a run of protocol from the role in the protocol, and inferring a principal＇s knowledge from the local observations of the principal. And we show analytically and empirically that this model can be easily reduced to Satisfiability （SAT） problem and efficiently implemented by a modern SAT solver.

Attempting to document and rehabilitate Aleppo between 1994 and 2011: the ramifications of pre-conflict built heritage mismanagement and the effects of the scarcity of documentation on options available for post-conflict conservation

This paper examines several aspects of the attempt at rehabilitating Aleppo and the data available about the city prior to the start of the Syrian conflict in 2011.It discusses documentation,rehabilitation and conservation practices in Aleppo,focusing on the operations between 1994 and 2011 that were coordinated by several institutions managed primarily by the Directorate of the Old City of Aleppo(DOCA)and the Gesellschaft fur Technische Zusammenarbeit(GTZ).The analysis considers not only the old city,which is inscribed on the World Heritage List,but also other historic and culturally significant areas in Aleppo.This research primarily uses notes from other scholarly resources,statements by various relevant experts,and the reports and documents produced by the DOCA,the GTZ,and UNESCO to argue that some of the practices during that period were in part responsible for overlooking important aspects and places of the city's built heritage.The paper then explains the ramification of these approaches,which are still perceptible today,on the prospects for any future efforts to safeguard the city's built heritage.

Multi-material additive manufacturing-functionally graded materials by means of laser remelting during laser powder bed fusion

Many processes may be used for manufacturing functionally graded materials.Among them,additive manufacturing seems to be predestined due to near-net shape manufacturing of complex geometries combined with the possibility of applying different materials in one component.By adjusting the powder composition of the starting material layer by layer,a macroscopic and step-like gradient can be achieved.To further improve the step-like gradient,an enhancement of the in-situ mixing degree,which is limited according to the state of the art,is necessary.In this paper,a novel technique for an enhancement of the in-situ material mixing degree in the melt pool by applying laser remelting(LR)is described.The effect of layer-wise LR on the formation of the interface was investigated using pure copper and low-alloy steel in a laser powder bed fusion process.Subsequent cross-sectional selective electron microscopic analyses were carried out.By applying LR,the mixing degree was enhanced,and the reaction zone thickness between the materials was increased.Moreover,an additional copper and iron-based phase was formed in the interface,resulting in a smoother gradient of the chemical composition than the case without LR.The Marangoni convection flow and thermal diffusion are the driving forces for the observed effect.

Explainable artificial intelligence and interpretable machine learning for agricultural data analysis

Artificial intelligence and machine learning have been increasingly applied for prediction in agricultural science.However,many models are typically black boxes,meaning we cannot explain what the models learned from the data and the reasons behind predictions.To address this issue,I introduce an emerging subdomain of artificial intelligence,explainable artificial intelligence(XAI),and associated toolkits,interpretable machine learning.This study demonstrates the usefulness of several methods by applying them to an openly available dataset.The dataset includes the no-tillage effect on crop yield relative to conventional tillage and soil,climate,and management variables.Data analysis discovered that no-tillage management can increase maize crop yield where yield in conventional tillage is<5000 kg/ha and the maximum temperature is higher than 32°.These methods are useful to answer(i)which variables are important for prediction in regression/classification,(ii)which variable interactions are important for prediction,(iii)how important variables and their interactions are associated with the response variable,(iv)what are the reasons underlying a predicted value for a certain instance,and(v)whether different machine learning algorithms offer the same answer to these questions.I argue that the goodness of model fit is overly evaluated with model performance measures in the current practice,while these questions are unanswered.XAI and interpretable machine learning can enhance trust and explainability in AI.

Soil conditions and phylogenetic relatedness influence total community trait space during early plant succession

Aims the total space of traits covered by the members of plant com-munities is an important parameter of ecosystem functioning and complexity.We trace the variability of trait space during early plant succession and ask how trait space co-varies with phylogenetic community structure and soil conditions.Particularly,we are inter-ested in the small-scale variability in trait space and the influence of biotic and abiotic filters.Methods We use data on species richness and soil conditions from the first 7 years of initial succession of an artificial catchment in north-east-ern germany.total functional attribute diversity serves as a proxy to total trait space.Important Findingstotal trait space steadily increased during succession.We observed high small-scale variability in total trait space that was positively correlated with species richness and phylogenetic segregation and negatively correlated with total plant cover.trait space increased with soil carbonate content,while pH and the fraction of sandy material behaved indifferently.our results indicate that during early succession,habitat filtering processes gain importance leading to a lesser increase in trait space than expected from the increase in species richness alone.

Eigenvalue sensitivity analysis based on the transfer matrix method

For linear mechanical systems,the transfer matrix method is one of the most efficient modeling and analysis methods.However,in contrast to classical mod-eling strategies,the final eigenvalue problem is based on a matrix which is a highly nonlinear function of the eigenvalues.Therefore,classical strategies for sensitivity analysis of eigenvalues w.r.t.system parameters cannot be applied.The paper develops two specific strategies for this situation,a direct differentiation strategy and an adjoint variable method,where especially the latter is easy to use and applicable to arbitrarily complex chain or branched multibody systems.Like the system analysis itself,it is able to break down the sensitivity analysis of the overall system to analytically determinable derivatives of element transfer matrices and recursive formula which can be applied along the transfer path of the topology figure.Several examples of different complexity validate the proposed approach by comparing results to analytical calculations and numerical differentiation.The obtained procedure may support gradient‐based optimization and robust design by delivering exact sensitivities.

Reduced multibody system transfer matrix method using decoupled hinge equations

In the multibody system transfer matrix method(MSTMM),the transfer matrix of body elements may be directly obtained from kinematic and kinetic equations.However,regarding the transfer matrices of hinge elements,typically information of their outboard body is involved complicating modeling and even resulting in combinatorial problems w.r.t.various types of outboard body's output links.This problem may be resolved by formulating decoupled hinge equations and introducing the Riccati transformation in the new version of MSTMM called the reduced multibody system transfer matrix method in this paper.Systematic procedures for chain,tree,closed-loop,and arbitrary general systems are defined,respectively,to generate the overall system equations satisfying the boundary conditions of the system during the entire computational process.As a result,accumulation errors are avoided and computational stability is guaranteed even for huge systems with long chains as demonstrated by examples and comparison with commercial software automatic dynamic analysis of the mechanical system.